diff --git a/.editorconfig b/.editorconfig
index 0fa425877232c..6d3f8a7f658e7 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -6,3 +6,6 @@ root = true
 indent_style = space
 indent_size = 2
 insert_final_newline = true
+
+[*.py]
+indent_size = 4
diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 20773c55c28cf..3cb1c9371896b 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -8,34 +8,35 @@
 
 # TODO: /.clang-format
 
-/.clang-tidy   @egorzhdan
+/.clang-tidy      @egorzhdan
 
-# TODO: /.dir-locals.el
+/.dir-locals.el   @al45tair
+/.editorconfig    @hamishknight
 # TODO: /.flake8
-# TODO: /.gitattributes
+/.gitattributes   @shahmishal
 
 # .github
 /.github/                                 @shahmishal
 /.github/CODEOWNERS                       @AnthonyLatsis @shahmishal
-/.github/ISSUE_TEMPLATE/                  @AnthonyLatsis @hborla @LucianoPAlmeida @shahmishal @xedin
-/.github/PULL_REQUEST_TEMPLATE.md         @AnthonyLatsis @hborla @LucianoPAlmeida @shahmishal @xedin
+/.github/ISSUE_TEMPLATE/                  @AnthonyLatsis @hborla @shahmishal @xedin
+/.github/PULL_REQUEST_TEMPLATE.md         @AnthonyLatsis @hborla @shahmishal @xedin
 
-# TODO: /.gitignore
+/.gitignore           @shahmishal
 # TODO: /.mailmap
 # TODO: /Brewfile
-# TODO: /CHANGELOG.md
+/CHANGELOG.md         @hborla
 # TODO: /CMakeLists.txt
-# TODO: /CODE_OF_CONDUCT.md
-# TODO: /CODE_OWNERS.TXT
-# TODO: /CONTRIBUTING.md
-# TODO: /LICENSE.txt
+/CODE_OF_CONDUCT.md   @swiftlang/core-team
+/CODE_OWNERS.TXT      @swiftlang/core-team
+/CONTRIBUTING.md      @AnthonyLatsis @xedin
+/LICENSE.txt          @swiftlang/core-team
 # TODO: /README.md
 
 # Runtimes
 /Runtimes/**/*.cmake                                    @etcwilde @compnerd @edymtt @justice-adams-apple
 /Runtimes/**/CMakeLists.txt                             @etcwilde @compnerd @edymtt @justice-adams-apple
 /Runtimes/Core/cmake/caches/Vendors/Apple/              @etcwilde @shahmishal @edymtt @justice-adams-apple
-/Runtimes/Core/cmake/modules/ExperimentalFeatures.cmake @tshortli @etcwilde @compnerd @edymtt @justice-adams-apple
+/Runtimes/*/cmake/modules/ExperimentalFeatures.cmake @tshortli @etcwilde @compnerd @edymtt @justice-adams-apple
 
 # SwiftCompilerSources
 /SwiftCompilerSources                     @eeckstein
@@ -60,7 +61,7 @@
 /docs/ABI/RegisterUsage.md                @al45tair
 /docs/CrossCompilationModel.md            @MaxDesiatov
 /docs/Generics                            @slavapestov
-/docs/HowToGuides/                        @AnthonyLatsis @LucianoPAlmeida @xedin
+/docs/HowToGuides/                        @AnthonyLatsis @xedin
 /docs/Optimizer*                          @eeckstein
 /docs/SIL*                                @jckarter
 /docs/Windows*                            @compnerd
@@ -81,11 +82,11 @@
 /include/swift/AST/DiagnosticsClangImporter.def    @zoecarver @egorzhdan @beccadax @ian-twilightcoder @Xazax-hun @j-hui @fahadnayyar @susmonteiro
 /include/swift/AST/DiagnosticsDriver.def           @artemcm
 /include/swift/AST/DiagnosticsFrontend.def         @artemcm @tshortli
-/include/swift/AST/DiagnosticsIDE.def              @ahoppen @bnbarham @hamishknight @rintaro
+/include/swift/AST/DiagnosticsIDE.def              @bnbarham @hamishknight @rintaro
 /include/swift/AST/DiagnosticsIRGen.def            @rjmccall
 /include/swift/AST/DiagnosticsModuleDiffer.def     @nkcsgexi
-/include/swift/AST/DiagnosticsParse.def            @ahoppen @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
-/include/swift/AST/DiagnosticsRefactoring.def      @ahoppen @bnbarham @hamishknight @rintaro
+/include/swift/AST/DiagnosticsParse.def            @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
+/include/swift/AST/DiagnosticsRefactoring.def      @bnbarham @hamishknight @rintaro
 /include/swift/AST/DiagnosticsSIL.def              @jckarter
 /include/swift/AST/Evaluator*                      @CodaFi @slavapestov
 /include/swift/Basic/                              @DougGregor
@@ -94,21 +95,21 @@
 /include/swift/DependencyScan                      @artemcm @cachemeifyoucan
 /include/swift/Driver*/                            @artemcm
 /include/swift/Frontend*/                          @artemcm @tshortli
-/include/swift/IDE/                                @ahoppen @bnbarham @hamishknight @rintaro
+/include/swift/IDE/                                @bnbarham @hamishknight @rintaro
 /include/swift/IRGen/                              @rjmccall
-/include/swift/Index/                              @ahoppen @bnbarham @hamishknight @rintaro
+/include/swift/Index/                              @bnbarham @hamishknight @rintaro
 /include/swift/Markup/                             @nkcsgexi
 /include/swift/Migrator/                           @nkcsgexi
 /include/swift/Option/*Options*                    @tshortli
-/include/swift/Parse/                              @ahoppen @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
+/include/swift/Parse/                              @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
 /include/swift/PrintAsClang                        @zoecarver @egorzhdan @Xazax-hun @j-hui @fahadnayyar @susmonteiro
-/include/swift/Refactoring                         @ahoppen @bnbarham @hamishknight @rintaro
+/include/swift/Refactoring                         @bnbarham @hamishknight @rintaro
 /include/swift/Runtime/                            @rjmccall @compnerd
 /include/swift/SIL/                                @jckarter
-/include/swift/SIL/*Coverage*                      @ahoppen @bnbarham @hamishknight @rintaro
+/include/swift/SIL/*Coverage*                      @bnbarham @hamishknight @rintaro
 /include/swift/SIL/*DebugInfo*                     @adrian-prantl
 /include/swift/SIL/SILDebug*                       @adrian-prantl
-/include/swift/SIL/SILProfiler.h                   @ahoppen @bnbarham @hamishknight @rintaro
+/include/swift/SIL/SILProfiler.h                   @bnbarham @hamishknight @rintaro
 /include/swift/SILOptimizer/                       @eeckstein
 /include/swift/SILOptimizer/Utils/Distributed*     @ktoso
 /include/swift/Sema/                               @hborla @slavapestov @xedin
@@ -133,7 +134,7 @@
 /lib/AST/Evaluator*                                 @CodaFi @slavapestov
 /lib/AST/ModuleLoader.cpp                           @artemcm
 /lib/AST/RequirementMachine/                        @slavapestov
-/lib/ASTGen/                                        @ahoppen @bnbarham @CodaFi @hamishknight @rintaro
+/lib/ASTGen/                                        @bnbarham @CodaFi @hamishknight @rintaro
 /lib/Basic/                                         @DougGregor
 /lib/Basic/Windows                                  @compnerd
 /lib/ClangImporter                                  @zoecarver @egorzhdan @beccadax @ian-twilightcoder @Xazax-hun @j-hui @fahadnayyar @susmonteiro
@@ -145,32 +146,34 @@
 /lib/DriverTool/sil_opt*                            @eeckstein
 /lib/DriverTool/swift_symbolgraph_extract_main.cpp  @QuietMisdreavus
 /lib/Frontend*/                                     @artemcm @tshortli
-/lib/IDE/                                           @ahoppen @bnbarham @hamishknight @rintaro
-/lib/IDETool/                                       @ahoppen @bnbarham @hamishknight @rintaro
+/lib/IDE/                                           @bnbarham @hamishknight @rintaro
+/lib/IDETool/                                       @bnbarham @hamishknight @rintaro
 /lib/IRGen/                                         @rjmccall
-/lib/IRGen/*Coverage*                               @ahoppen @bnbarham @hamishknight @rintaro
+/lib/IRGen/*Coverage*                               @bnbarham @hamishknight @rintaro
 /lib/IRGen/*Debug*                                  @adrian-prantl
 /lib/IRGen/*Distributed*                            @ktoso
-/lib/Index/                                         @ahoppen @bnbarham @hamishknight @rintaro
+/lib/Index/                                         @bnbarham @hamishknight @rintaro
 /lib/Macros/Sources/SwiftMacros/Swiftify*           @hnrklssn @Xazax-hun
 /lib/Markup/                                        @nkcsgexi
 /lib/Migrator/                                      @nkcsgexi
-/lib/Parse/                                         @ahoppen @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
+/lib/Parse/                                         @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
 /lib/PrintAsClang                                   @zoecarver @egorzhdan @Xazax-hun @j-hui @fahadnayyar @susmonteiro
-/lib/Refactoring/                                   @ahoppen @bnbarham @hamishknight @rintaro
+/lib/Refactoring/                                   @bnbarham @hamishknight @rintaro
 /lib/SIL/                                           @jckarter
 /lib/SIL/**/*DebugInfo*                             @adrian-prantl
-/lib/SIL/IR/*Coverage*                              @ahoppen @bnbarham @hamishknight @rintaro
+/lib/SIL/IR/*Coverage*                              @bnbarham @hamishknight @rintaro
 /lib/SIL/IR/SILDebug*                               @adrian-prantl
 /lib/SIL/IR/SILLocation*                            @adrian-prantl
-/lib/SIL/IR/SILProfiler.cpp                         @ahoppen @bnbarham @hamishknight @rintaro
-/lib/SILGen/                                        @jckarter
+/lib/SIL/IR/SILProfiler.cpp                         @bnbarham @hamishknight @rintaro
+/lib/SILGen/                                        @jckarter @kavon
+/lib/SILGen/*Availability*                          @tshortli
 /lib/SILGen/*Distributed*                           @ktoso
 /lib/SILOptimizer/                                  @eeckstein
 /lib/SILOptimizer/**/*DebugInfo*                    @adrian-prantl
 /lib/SILOptimizer/Mandatory/ConsumeOperator*        @kavon
 /lib/SILOptimizer/Mandatory/FlowIsolation.cpp       @kavon
 /lib/SILOptimizer/Mandatory/MoveOnly*               @kavon
+/lib/SILOptimizer/Mandatory/AddressLowering*        @kavon
 /lib/SILOptimizer/Utils/Distributed*                @ktoso
 /lib/Sema/                                          @hborla @slavapestov @xedin
 /lib/Sema/*Availability*                            @tshortli
@@ -195,11 +198,13 @@
 # stdlib
 /stdlib/                                  @swiftlang/standard-librarians
 /stdlib/private/*Runtime*/                @rjmccall
+/stdlib/private/DifferentiationUnittest/  @asl
 /stdlib/private/SwiftReflectionTest/      @slavapestov
 /stdlib/public/core/Swiftify*             @hnrklssn @Xazax-hun
 /stdlib/public/*Demangl*/                 @rjmccall
 /stdlib/public/Concurrency/               @ktoso
 /stdlib/public/Cxx/                       @zoecarver @egorzhdan @Xazax-hun @j-hui @fahadnayyar @susmonteiro
+/stdlib/public/Differentiation/           @asl
 /stdlib/public/Distributed/               @ktoso
 /stdlib/public/Observation/               @phausler
 /stdlib/public/RuntimeModule/             @al45tair @mikeash
@@ -212,7 +217,9 @@
 
 # test
 /test/*Demangl*/                                    @rjmccall
-/test/ASTGen/                                       @ahoppen @bnbarham @CodaFi @hamishknight @rintaro
+/test/Availability/                                 @tshortli
+/test/ASTGen/                                       @bnbarham @CodaFi @hamishknight @rintaro
+/test/AutoDiff/                                     @asl
 /test/Concurrency/                                  @ktoso
 /test/Constraints/                                  @hborla @xedin
 /test/DebugInfo/                                    @adrian-prantl
@@ -222,14 +229,14 @@
 /test/Frontend/                                     @artemcm @tshortli
 /test/Generics/                                     @hborla @slavapestov
 /test/Generics/inverse*                             @kavon
-/test/IDE/                                          @ahoppen @bnbarham @hamishknight @rintaro
-/test/IRGen/                                        @rjmccall
-/test/Index/                                        @ahoppen @bnbarham @hamishknight @rintaro
+/test/IDE/                                          @bnbarham @hamishknight @rintaro
+/test/IRGen/                                        @AnthonyLatsis @rjmccall
+/test/Index/                                        @bnbarham @hamishknight @rintaro
 /test/Interop/                                      @zoecarver @egorzhdan @Xazax-hun @j-hui @fahadnayyar @susmonteiro @hnrklssn
 /test/Macros/SwiftifyImport                         @hnrklssn @Xazax-hun
 /test/Migrator/                                     @nkcsgexi
-/test/Parse/                                        @ahoppen @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
-/test/Profiler                                      @ahoppen @bnbarham @hamishknight @rintaro
+/test/Parse/                                        @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
+/test/Profiler                                      @bnbarham @hamishknight @rintaro
 /test/Reflection/                                   @slavapestov
 /test/Runtime/                                      @rjmccall
 /test/SIL/                                          @jckarter
@@ -241,7 +248,7 @@
 /test/Sema/                                         @hborla @slavapestov @xedin
 /test/Sema/moveonly*                                @kavon
 /test/Serialization/                                @xymus
-/test/SourceKit/                                    @ahoppen @bnbarham @hamishknight @rintaro
+/test/SourceKit/                                    @bnbarham @hamishknight @rintaro
 /test/SymbolGraph/                                  @QuietMisdreavus
 /test/abi/                                          @swiftlang/standard-librarians
 /test/decl/                                         @hborla @slavapestov
@@ -249,7 +256,7 @@
 # FIXME: This file could have a dedicated directory.
 /test/decl/protocol/special/DistributedActor.swift  @ktoso
 /test/expr/                                         @hborla @slavapestov @xedin
-/test/refactoring/                                  @ahoppen @bnbarham @hamishknight @rintaro
+/test/refactoring/                                  @bnbarham @hamishknight @rintaro
 /test/sil*                                          @jckarter
 /test/sil-opt*                                      @eeckstein
 /test/stdlib/                                       @swiftlang/standard-librarians
@@ -259,13 +266,13 @@
 # tools
 # TODO: /tools
 /tools/*reflection/                                 @slavapestov
-/tools/SourceKit                                    @ahoppen @bnbarham @hamishknight @rintaro
+/tools/SourceKit                                    @bnbarham @hamishknight @rintaro
 /tools/driver/                                      @artemcm
 /tools/lldb-moduleimport-test/                      @adrian-prantl
 /tools/swift-demangle*                              @rjmccall
-/tools/swift-ide-test                               @ahoppen @bnbarham @hamishknight @rintaro
+/tools/swift-ide-test                               @bnbarham @hamishknight @rintaro
 /tools/swift-inspect                                @mikeash @al45tair @compnerd
-/tools/swift-refactor                               @ahoppen @bnbarham @hamishknight @rintaro
+/tools/swift-refactor                               @bnbarham @hamishknight @rintaro
 
 # unittests
 /unittests/*Demangl*/                     @rjmccall
@@ -273,11 +280,11 @@
 /unittests/AST/*Evaluator*                @CodaFi @slavapestov
 /unittests/DependencyScan/                @artemcm @cachemeifyoucan
 /unittests/Frontend*/                     @artemcm @tshortli
-/unittests/Parse/                         @ahoppen @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
+/unittests/Parse/                         @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
 /unittests/Reflection/                    @slavapestov
 /unittests/SIL/                           @jckarter
 /unittests/Sema/                          @hborla @xedin
-/unittests/SourceKit/                     @ahoppen @bnbarham @rintaro @hamishknight
+/unittests/SourceKit/                     @bnbarham @rintaro @hamishknight
 /unittests/runtime/                       @rjmccall
 
 # userdocs
@@ -285,24 +292,36 @@
 
 # utils
 /utils/*windows*                                              @compnerd
+/utils/availability-macros.def                                @swiftlang/standard-librarians
+/utils/build.ps1                                              @compnerd
+/utils/build_swift/                                           @etcwilde @justice-adams-apple @shahmishal
 /utils/generate-xcode                                         @hamishknight
-/utils/gyb_sourcekit_support/                                 @ahoppen @bnbarham @hamishknight @rintaro
-/utils/sourcekit_fuzzer/                                      @ahoppen @bnbarham @hamishknight @rintaro
+/utils/gen-unicode-data                                       @swiftlang/standard-librarians
+/utils/gyb                                                    @swiftlang/standard-librarians
+/utils/gyb_foundation_support.py                              @swiftlang/standard-librarians
+/utils/gyb_sourcekit_support/                                 @bnbarham @hamishknight @rintaro
+/utils/gyb_stdlib_support.py                                  @swiftlang/standard-librarians
+/utils/gyb.py                                                 @swiftlang/standard-librarians
+/utils/sourcekit_fuzzer/                                      @bnbarham @hamishknight @rintaro
 /utils/swift-xcodegen/                                        @hamishknight
-/utils/swift_build_support/products/earlyswiftsyntax.py       @ahoppen @bnbarham @hamishknight @rintaro
-/utils/swift_build_support/products/skstresstester.py         @ahoppen @bnbarham @hamishknight @rintaro
-/utils/swift_build_support/products/sourcekitlsp.py           @ahoppen @bnbarham @hamishknight @rintaro
-/utils/swift_build_support/products/swiftformat.py            @ahoppen @allevato @bnbarham @hamishknight @rintaro
-/utils/swift_build_support/products/swiftsyntax.py            @ahoppen @bnbarham @hamishknight @rintaro
-/utils/update-checkout*                                       @shahmishal
-/utils/update_checkout/                                       @shahmishal
+/utils/swift_build_support/                                   @etcwilde @justice-adams-apple @shahmishal
+/utils/swift_build_support/products/earlyswiftsyntax.py       @bnbarham @hamishknight @rintaro
+/utils/swift_build_support/products/skstresstester.py         @bnbarham @hamishknight @rintaro
+/utils/swift_build_support/products/sourcekitlsp.py           @bnbarham @hamishknight @rintaro
+/utils/swift_build_support/products/swiftformat.py            @allevato @bnbarham @hamishknight @rintaro
+/utils/swift_build_support/products/swiftsyntax.py            @bnbarham @hamishknight @rintaro
+/utils/swift_build_support/products/wasm*                     @bnbarham @MaxDesiatov @kateinoigakukun
+/utils/swift_build_support/products/wasi*                     @bnbarham @MaxDesiatov @kateinoigakukun
+/utils/update-checkout*                                       @etcwilde @justice-adams-apple @shahmishal
+/utils/update_checkout/                                       @etcwilde @justice-adams-apple @shahmishal
+/utils/update_checkout/update-checkout-config.json            @shahmishal
 /utils/vim/                                                   @compnerd
 
 # validation-test
 /validation-test/Driver/                  @artemcm
-/validation-test/IDE/                     @ahoppen @bnbarham @rintaro @hamishknight
+/validation-test/IDE/                     @bnbarham @rintaro @hamishknight
 /validation-test/IRGen/                   @rjmccall
-/validation-test/Parse/                   @ahoppen @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
+/validation-test/Parse/                   @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
 /validation-test/Reflection/              @slavapestov
 /validation-test/Runtime/                 @rjmccall
 /validation-test/SIL/                     @jckarter
diff --git a/.github/ISSUE_TEMPLATE/task.yml b/.github/ISSUE_TEMPLATE/task.yml
index c31a5e9b13306..64dd31ae65c95 100644
--- a/.github/ISSUE_TEMPLATE/task.yml
+++ b/.github/ISSUE_TEMPLATE/task.yml
@@ -18,7 +18,7 @@ body:
         This repository hosts the Swift compiler, the Swift standard library,
         the Swift runtime, SourceKit, and IDE support for the Swift language.
         It does *not* track feedback on Xcode and other closed source Apple
-        deeloper software such as SwiftUI and UIKit; please direct it to
+        developer software such as SwiftUI and UIKit; please direct it to
         [Feedback Assistant](https://developer.apple.com/bug-reporting)
         instead.
   - type: textarea
diff --git a/.gitignore b/.gitignore
index bd9bbcfcec8cb..f4cb9086f296c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -89,6 +89,8 @@ Runtimes/**/*.cpp
 Runtimes/**/*.c
 Runtimes/**/*.m
 Runtimes/**/*.mm
+Runtimes/**/*.S
+Runtimes/**/*.asm
 Runtimes/**/*.def
 Runtimes/**/*.gyb
 Runtimes/**/*.apinotes
@@ -97,3 +99,5 @@ Runtimes/**/*.inc
 Runtimes/**/*.json
 Runtimes/**/*.modulemap
 Runtimes/**/*.in
+!Runtimes/**/*.cmake.in
+!Runtimes/**/CMakeConfig.h.in
diff --git a/Brewfile b/Brewfile
index d965eb21aaefa..a3dbeb5aa8f4c 100644
--- a/Brewfile
+++ b/Brewfile
@@ -1,3 +1,2 @@
-brew "cmake"
 brew "ninja"
 brew "sccache"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d2bb92dd34743..7cc63bc9baf08 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,8 +3,195 @@
 > [!NOTE]
 > This is in reverse chronological order, so newer entries are added to the top.
 
+## Swift (next)
+
+* Concurrency-related APIs like `Task` and string-processing-related APIs like `Regex` can now be qualified by the name
+  `Swift`, just like other standard library APIs:
+  
+  ```swift
+  Swift.Task { ... }
+  func match(_ regex: Swift.Regex<(Substring)>) { ... }
+  ```
+  
+  The old `_Concurrency` and `_StringProcessing` names are still supported for backwards compatibility, and Embedded
+  Swift projects must still explicitly `import _Concurrency` to access concurrency APIs.
+
 ## Swift 6.2
 
+* [SE-0472][]:
+  Introduced new `Task.immediate` and `taskGroup.addImmediateTask` APIs, which allow a task to run "immediately" in the
+  calling context if its isolation is compatible with the enclosing one. This can be used to create tasks which execute 
+  without additional scheduling overhead, and allow for finer-grained control over where a task begins running.
+
+  The canonical example for using this new API is using an unstructured immediate task like this:
+  
+  ```swift
+  func synchronous() { // synchronous function
+  // executor / thread: "T1"
+  let task: Task<Void, Never> = Task.immediate {
+  // executor / thread: "T1"
+  guard keepRunning() else { return } // synchronous call (1)
+  
+      // executor / thread: "T1"
+      await noSuspension() // potential suspension point #1 // (2)
+      
+      // executor / thread: "T1"
+      await suspend() // potential suspension point #2 // (3), suspend, (5)
+      // executor / thread: "other"
+  }
+  
+  // (4) continue execution
+  // executor / thread: "T1"
+  }
+  ```
+
+* [SE-0471][]:
+  Actor and global actor annotated types may now declare a synchronous `isolated deinit`, which allows such deinitializer
+  to access actor isolated state while deinitializing the actor. This enables actor deinitializers to safely access
+  and shut down or close resources during an actors deinitialization, without explicitly resorting to unstructured 
+  concurrency tasks.
+
+  ```swift
+  class NonSendableAhmed { 
+    var state: Int = 0
+  }
+
+  @MainActor
+  class Maria {
+    let friend: NonSendableAhmed
+
+    init() {
+      self.friend = NonSendableAhmed()
+    }
+
+    init(sharingFriendOf otherMaria: Maria) {
+      // While the friend is non-Sendable, this initializer and
+      // and the otherMaria are isolated to the MainActor. That is,
+      // they share the same executor. So, it's OK for the non-Sendable value
+      // to cross between otherMaria and self.
+      self.friend = otherMaria.friend
+    }
+    
+    isolated deinit {
+      // Used to be a potential data race. Now, deinit is also
+      // isolated on the MainActor, so this code is perfectly
+      // correct.
+      friend.state += 1
+    }
+  }
+    
+  func example() async {
+    let m1 = await Maria()
+    let m2 = await Maria(sharingFriendOf: m1)
+    doSomething(m1, m2)
+  }
+  ```
+
+* [SE-0469][]:
+  Swift concurrency tasks (both unstructured and structured, via the TaskGroup `addTask` APIs) may now be given 
+  human-readable names, which can be used to support debugging and identifying tasks.
+
+  ```swift
+  let getUsers = Task("Get Users for \(accountID)") {
+    await users.get(accountID)
+  }
+  ```
+
+* [SE-0462][]:
+  Task priority escalation may now be explicitly caused to a `Task`, as well as reacted to using the new task priority escalation handlers:      
+
+  ```swift
+  // priority: low
+  // priority: high!
+  await withTaskPriorityEscalationHandler {
+  await work()
+  } onPriorityEscalated: { newPriority in // may not be triggered if ->high escalation happened before handler was installed
+  // do something
+  }
+  ```
+* [SE-0461][]:
+  Nonisolated asynchronous functions may now execute on the calling actor, when the upcoming feature `NonisolatedNonsendingByDefault`
+  is enabled, or when explicitly opted-into using the `nonisolated(nonsending)` keywords. This allows for fine grained control
+  over where nonisolated asynchronous functions execute, and allows for the default behavior of their execution to be changed
+  from always executing on the global concurrent pool, to the calling actor, which can yield noticeable performance improvements 
+  thanks to less executor hopping when nonisolated and isolated code is invoked in sequence. 
+  
+  This also allows for safely using asynchronous functions on non-sendable types from actors, like so:
+
+  ```swift
+  class NotSendable {
+    func performSync() { ... }
+
+    nonisolated(nonsending)
+    func performAsync() async { ... }
+  }
+
+  actor MyActor {
+    let x: NotSendable
+
+    func call() async {
+      x.performSync() // okay
+
+      await x.performAsync() // okay
+    }
+  }
+  ```
+
+* The Swift compiler no longer diagnoses references to declarations that are
+  potentially unavailable because the platform version might not be new enough
+  when those references occur inside of contexts that are also unavailable to
+  that platform. This addresses a long-standing nuisance for multi-platform
+  code. However, there is also a chance that existing source code may become
+  ambiguous as a result:
+
+  ```swift
+  struct A {}
+  struct B {}
+
+  func potentiallyAmbiguous(_: A) {}
+
+  @available(macOS 99, *)
+  func potentiallyAmbiguous(_: B) {}
+
+  @available(macOS, unavailable)
+  func unavailableOnMacOS() {
+    potentiallyAmbiguous(.init()) // error: ambiguous use of 'init()'
+  }
+  ```
+
+  Code that is now ambiguous as a result should likely be restructured since
+  disambiguation based on platform introduction alone has never been a reliable
+  strategy, given that the code would eventually become ambiguous anyways when
+  the deployment target is raised.
+
+* [SE-0470][]:
+  A protocol conformance can be isolated to a specific global actor, meaning that the conformance can only be used by code running on that actor. Isolated conformances are expressed by specifying the global actor on the conformance itself:
+
+  ```swift
+  protocol P {
+    func f()
+  }
+
+  @MainActor
+  class MyType: @MainActor P {
+    /*@MainActor*/ func f() {
+      // must be called on the main actor
+    }
+  }
+  ```
+
+  Swift will produce diagnostics if the conformance is directly accessed in code that isn't guaranteed to execute in the same global actor. For example:
+
+  ```swift
+  func acceptP<T: P>(_ value: T) { }
+
+  /*nonisolated*/ func useIsolatedConformance(myType: MyType) {
+    acceptP(myType) // error: main actor-isolated conformance of 'MyType' to 'P' cannot be used in nonisolated context
+  }
+  ```
+
+  To address such issues, only use an isolated conformance from code that executes on the same global actor.
+
 * [SE-0419][]:
   Introduced the new `Runtime` module, which contains a public API that can
   generate backtraces, presently supported on macOS and Linux.  Capturing a
@@ -392,7 +579,7 @@ And the module structure to support such applications looks like this:
 
 * [SE-0430][]:
 
-  Region Based Isolation is now extended to enable the application of an
+  Region-Based Isolation is now extended to enable the application of an
   explicit `sending` annotation to function parameters and results. A function
   parameter or result that is annotated with `sending` is required to be
   disconnected at the function boundary and thus possesses the capability of
@@ -430,7 +617,7 @@ And the module structure to support such applications looks like this:
   
   func useValue() {
     let x = NonSendableType()
-    let a = await MyActor(x) // Error without Region Based Isolation!
+    let a = await MyActor(x) // Error without Region-Based Isolation!
   }
   ```
 
@@ -10732,6 +10919,12 @@ using the `.dynamicType` member to retrieve the type of an expression should mig
 [SE-0442]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0442-allow-taskgroup-childtaskresult-type-to-be-inferred.md
 [SE-0444]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0444-member-import-visibility.md
 [SE-0458]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0458-strict-memory-safety.md
+[SE-0461]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0461-async-function-isolation.md
+[SE-0462]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0462-task-priority-escalation-apis.md
+[SE-0469]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0469-task-names.md
+[SE-0470]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0470-isolated-conformances.md
+[SE-0471]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0371-isolated-synchronous-deinit.md
+[SE-0472]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0472-task-start-synchronously-on-caller-context.md
 [#64927]: <https://github.com/apple/swift/issues/64927>
 [#42697]: <https://github.com/apple/swift/issues/42697>
 [#42728]: <https://github.com/apple/swift/issues/42728>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index fa5cf4d0661a9..9eb5c044bf96f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -336,6 +336,8 @@ set(SWIFT_COMPILER_VERSION "" CACHE STRING
     "The internal version of the Swift compiler")
 set(CLANG_COMPILER_VERSION "" CACHE STRING
     "The internal version of the Clang compiler")
+set(SWIFT_TOOLCHAIN_VERSION "" CACHE STRING
+    "The Swift compiler tag")
 
 option(SWIFT_DISABLE_DEAD_STRIPPING
       "Turn off Darwin-specific dead stripping for Swift host tools." FALSE)
@@ -462,6 +464,10 @@ option(SWIFT_STDLIB_ASSERTIONS
     "Enable internal checks for the Swift standard library (useful for debugging the library itself, does not affect checks required for safety)"
     "${SWIFT_STDLIB_ASSERTIONS_default}")
 
+option(SWIFT_STDLIB_ENABLE_STRICT_AVAILABILITY
+       "Enable strict availability; this will cause things to break at desk or in CI if the host OS is a lower version than some `@availability` annotations in the runtime code"
+       FALSE)
+
 option(SWIFT_BUILD_RUNTIME_WITH_HOST_COMPILER
        "Use the host compiler and not the internal clang to build the swift runtime"
        FALSE)
@@ -624,6 +630,17 @@ set(COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_WATCHOS "2.0")
 set(COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_XROS "1.0")
 set(COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_MACCATALYST "13.1")
 
+set(SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX "${SWIFT_DARWIN_DEPLOYMENT_VERSION_OSX}" CACHE STRING
+    "Deployment target version for building macOS tests")
+set(SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS "${SWIFT_DARWIN_DEPLOYMENT_VERSION_IOS}" CACHE STRING
+    "Deployment target version for building iOS tests")
+set(SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS "${SWIFT_DARWIN_DEPLOYMENT_VERSION_TVOS}" CACHE STRING
+    "Deployment target version for building tvOS tests")
+set(SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS "${SWIFT_DARWIN_DEPLOYMENT_VERSION_WATCHOS}" CACHE STRING
+    "Deployment target version for building watchOS tests")
+set(SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS "${SWIFT_DARWIN_DEPLOYMENT_VERSION_XROS}" CACHE STRING
+    "Deployment target version for building visionOS tests")
+
 #
 # User-configurable debugging options.
 #
@@ -818,6 +835,9 @@ elseif(UNIX)
   include(UnixCompileRules)
 endif()
 
+# Add any extra C++ compilation options that were passed down.
+add_compile_options($<$<COMPILE_LANGUAGE:CXX>:${SWIFT_EXTRA_CXX_FLAGS}>)
+
 if(CMAKE_C_COMPILER_ID MATCHES Clang)
   add_compile_options($<$<OR:$<COMPILE_LANGUAGE:C>,$<COMPILE_LANGUAGE:CXX>>:-Werror=gnu>)
 endif()
@@ -828,6 +848,19 @@ if(CMAKE_C_COMPILER_ID MATCHES Clang)
   add_compile_options($<$<COMPILE_LANGUAGE:CXX>:-Werror=c++98-compat-extra-semi>)
 endif()
 
+if(CMAKE_CXX_COMPILER_ID MATCHES Clang)
+  include(CheckCXXCompilerFlag)
+  # Check for '-fsized-deallocation', which we need in IRGen. Clang presumably
+  # adds this flag as a requirement for C++14+ to avoid a potential source
+  # compatibility issue with C++11 where the 2-parameter `operator delete` was
+  # used for placement deletion.
+  check_cxx_compiler_flag("-fsized-deallocation"
+    CXX_SUPPORTS_FSIZED_DEALLOCATION)
+  if(CXX_SUPPORTS_FSIZED_DEALLOCATION)
+    add_compile_options($<$<COMPILE_LANGUAGE:CXX>:-fsized-deallocation>)
+  endif()
+endif()
+
 option(SWIFT_BUILD_SWIFT_SYNTAX
   "Enable building swift syntax"
   FALSE)
@@ -868,12 +901,7 @@ include(CMakePushCheckState)
 
 # Print out path and version of any installed commands
 message(STATUS "CMake (${CMAKE_COMMAND}) Version: ${CMAKE_VERSION}")
-if(XCODE)
-  set(version_flag -version)
-else()
-  set(version_flag --version)
-endif()
-execute_process(COMMAND ${CMAKE_MAKE_PROGRAM} ${version_flag}
+execute_process(COMMAND ${CMAKE_MAKE_PROGRAM} --version
   OUTPUT_VARIABLE _CMAKE_MAKE_PROGRAM_VERSION
   OUTPUT_STRIP_TRAILING_WHITESPACE)
 message(STATUS "CMake Make Program (${CMAKE_MAKE_PROGRAM}) Version: ${_CMAKE_MAKE_PROGRAM_VERSION}")
@@ -1070,6 +1098,8 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   set(SWIFT_USE_LINKER_default "")
 elseif(DISTRO_NAME STREQUAL "Amazon Linux 2023")
   set(SWIFT_USE_LINKER_default "lld")
+elseif(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
+	set(SWIFT_USE_LINKER_default "lld")
 else()
   get_gold_version(gold_version)
   if(NOT gold_version)
@@ -1141,14 +1171,6 @@ endif()
 # Configure SDKs.
 #
 
-if(XCODE)
-  # FIXME: It used to be the case that Xcode would force
-  # -m${platform}-version-min flags that would conflict with those computed
-  # by build-script. version-min flags are deprecated in favor of -target since
-  # clang-11, so we might be able to undo this.
-  set(SWIFT_SDKS "OSX")
-endif()
-
 # FIXME: the parameters we specify in SWIFT_SDKS are lacking architecture specifics,
 # so we need to hard-code it. For example, the SDK for Android is just 'ANDROID',
 # and we have to specify SWIFT_SDK_ANDROID_ARCHITECTURES separately.
@@ -1404,8 +1426,9 @@ endif()
 
 if(SWIFT_BUILD_STDLIB OR SWIFT_BUILD_SDK_OVERLAY)
   message(STATUS "Building Swift standard library and overlays for SDKs: ${SWIFT_SDKS}")
-  message(STATUS "  Build type:       ${SWIFT_STDLIB_BUILD_TYPE}")
-  message(STATUS "  Assertions:       ${SWIFT_STDLIB_ASSERTIONS}")
+  message(STATUS "  Build type:               ${SWIFT_STDLIB_BUILD_TYPE}")
+  message(STATUS "  Assertions:               ${SWIFT_STDLIB_ASSERTIONS}")
+  message(STATUS "  Strict availability:      ${SWIFT_STDLIB_ENABLE_STRICT_AVAILABILITY}")
   message(STATUS "")
 
   message(STATUS "Building Swift runtime with:")
@@ -1590,22 +1613,6 @@ swift_install_in_component(FILES "LICENSE.txt"
                            DESTINATION "share/swift"
                            COMPONENT license)
 
-# Add a documentation target so that documentation shows up in the
-# Xcode project.
-if(XCODE)
-  add_custom_target(Documentation
-      SOURCES
-        README.md
-        docs)
-
-  file(GLOB SWIFT_TOPLEVEL_HEADERS
-      ${CMAKE_CURRENT_SOURCE_DIR}/include/swift${dir}/*.h
-      ${CMAKE_CURRENT_SOURCE_DIR}/include/swift${dir}/*.td
-      ${CMAKE_CURRENT_SOURCE_DIR}/include/swift${dir}/*.def)
-  add_custom_target(Miscellaneous
-      SOURCES ${SWIFT_TOPLEVEL_HEADERS})
-endif()
-
 # New standard library build
 option(SWIFT_ENABLE_NEW_RUNTIME_BUILD "Build Swift runtimes with new build system" OFF)
 if(SWIFT_ENABLE_NEW_RUNTIME_BUILD)
@@ -1633,6 +1640,12 @@ if(SWIFT_ENABLE_NEW_RUNTIME_BUILD)
         set(stdlib_deployment_version_flag -DCMAKE_OSX_DEPLOYMENT_TARGET=${SWIFT_SDK_${sdk}_DEPLOYMENT_VERSION})
       endif()
 
+      if(sdk STREQUAL "OSX" AND SWIFT_SDK_${sdk}_DEPLOYMENT_VERSION VERSION_LESS "10.15")
+        set(build_concurrency NO)
+      else()
+        set(build_concurrency YES)
+      endif()
+
       ExternalProject_Add("${stdlib_target}-core"
         SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/Runtimes/Core"
         # TODO: Add this once we're ready to start swapping out the libraries
@@ -1640,6 +1653,8 @@ if(SWIFT_ENABLE_NEW_RUNTIME_BUILD)
         # INSTALL_DIR "${CMAKE_BINARY_DIR}/"
 
         DEPENDS PopulateRuntimeSourceDir
+        # To ensure incremental builds work as expected
+        BUILD_ALWAYS 1
         CMAKE_ARGS
           -DCMAKE_INSTALL_LIBDIR:FILEPATH=lib
           # Compiler will see mismatched swift modules and fail initial checks
@@ -1658,19 +1673,20 @@ if(SWIFT_ENABLE_NEW_RUNTIME_BUILD)
           -DCMAKE_COLOR_DIAGNOSTICS:BOOLEAN=${CMAKE_COLOR_DIAGNOSTICS}
           -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
           -DSwiftCore_INSTALL_NESTED_SUBDIR=YES
-          -DSwiftCore_ENABLE_CONCURRENCY=YES)
+          -DSwiftCore_ENABLE_CONCURRENCY=${build_concurrency})
       if(NOT ${CMAKE_CROSSCOMPILING})
         add_dependencies("${stdlib_target}-core" swift-frontend)
       endif()
 
       ExternalProject_Get_Property("${stdlib_target}-core" INSTALL_DIR)
 
-      ExternalProject_Add("${stdlib_target}-StringProcessing"
-        SOURCE_DIR
-          "${CMAKE_CURRENT_SOURCE_DIR}/Runtimes/Supplemental/StringProcessing"
+      ExternalProject_Add("${stdlib_target}-Overlay"
+        SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/Runtimes/Overlay"
         DEPENDS "${stdlib_target}-core"
         INSTALL_DIR "${INSTALL_DIR}"
-        INSTALL_COMMAND "" # No install story set up yet
+        LIST_SEPARATOR "|"
+        # To ensure incremental builds work as expected
+        BUILD_ALWAYS 1
         CMAKE_ARGS
           -DBUILD_SHARED_LIBS=YES
           -DCMAKE_Swift_COMPILER_WORKS:BOOLEAN=YES
@@ -1683,7 +1699,32 @@ if(SWIFT_ENABLE_NEW_RUNTIME_BUILD)
           -DCMAKE_C_COMPILER_TARGET:STRING=${stdlib_target_triple}
           -DCMAKE_CXX_COMPILER_TARGET:STRING=${stdlib_target_triple}
           -DCMAKE_COLOR_DIAGNOSTICS:BOOLEAN=${CMAKE_COLOR_DIAGNOSTICS}
-          -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM})
+          -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
+          -DCMAKE_FIND_PACKAGE_PREFER_CONFIG=TRUE)
+
+      ExternalProject_Add("${stdlib_target}-Supplemental"
+        SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/Runtimes/Supplemental"
+        DEPENDS "${stdlib_target}-core" "${stdlib_target}-Overlay"
+        INSTALL_DIR "${INSTALL_DIR}"
+        INSTALL_COMMAND ""
+        LIST_SEPARATOR "|"
+        # To ensure incremental builds work as expected
+        BUILD_ALWAYS 1
+        CMAKE_ARGS
+          -DSwift_ENABLE_RUNTIMES=StringProcessing|Synchronization|Distributed|Observation
+          -DBUILD_SHARED_LIBS=YES
+          -DCMAKE_Swift_COMPILER_WORKS:BOOLEAN=YES
+          -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
+          -DCMAKE_INSTALL_PREFIX:FILEPATH=${INSTALL_DIR}
+          -DCMAKE_Swift_COMPILER:FILEPATH=$<IF:$<BOOL:${CMAKE_CROSSCOMPILING}>,${CMAKE_Swift_COMPILER},$<PATH:REPLACE_FILENAME,$<TARGET_FILE:swift-frontend>,swiftc>>
+          -DCMAKE_C_COMPILER:FILEPATH=${CMAKE_C_COMPILER}
+          -DCMAKE_CXX_COMPILER:FILEPATH=${CMAKE_CXX_COMPILER}
+          -DCMAKE_Swift_COMPILER_TARGET:STRING=${stdlib_target_triple}
+          -DCMAKE_C_COMPILER_TARGET:STRING=${stdlib_target_triple}
+          -DCMAKE_CXX_COMPILER_TARGET:STRING=${stdlib_target_triple}
+          -DCMAKE_COLOR_DIAGNOSTICS:BOOLEAN=${CMAKE_COLOR_DIAGNOSTICS}
+          -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
+          -DCMAKE_FIND_PACKAGE_PREFER_CONFIG=TRUE)
     endforeach()
   endforeach()
 endif()
diff --git a/README.md b/README.md
index 1f79f00830ff4..aa3222fbb1b40 100644
--- a/README.md
+++ b/README.md
@@ -5,39 +5,20 @@
 
 # Swift Programming Language
 
-
-| | **Architecture** | **Build** |
-|---|:---:|:---:|
-| **macOS**        | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-macos/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-macos)|
-| **Ubuntu 20.04** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04)|
-| **Ubuntu 20.04** | AArch64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04-aarch64/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04-aarch64)|
-| **Ubuntu 22.04** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04)|
-| **Ubuntu 22.04** | AArch64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04-aarch64/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04-aarch64)|
-| **Ubuntu 24.04** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-24_04/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubuntu-24_04)|
-| **Ubuntu 24.04** | AArch64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-24_04-aarch64/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubuntu-24_04-aarch64)|
-| **Amazon Linux 2** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-amazon-linux-2/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-amazon-linux-2)|
-| **Amazon Linux 2** | AArch64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-amazon-linux-2-aarch64/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-amazon-linux-2-aarch64)|
-| **Universal Base Image 9** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubi-9/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubi-9)|
-| **Debian 12** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-debian-12/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-debian-12)|
-| **Debian 12** | AArch64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-debian-12-aarch64/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-debian-12-aarch64)|
-| **Fedora 39** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-fedora-39/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-fedora-39)|
-| **Fedora 39** | AArch64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-fedora-39-aarch64/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-fedora-39-aarch64)|
-| **Windows 10** | x86_64 |[![Build Status](https://ci-external.swift.org/job/swift-main-windows-toolchain/lastCompletedBuild/badge/icon)](https://ci-external.swift.org/job/swift-main-windows-toolchain)|
-| **Windows 10** | ARM64 |[![Build Status](https://ci-external.swift.org/job/swift-main-windows-toolchain-arm64/lastCompletedBuild/badge/icon)](https://ci-external.swift.org/job/swift-main-windows-toolchain-arm64)|
-
-**Cross-Compilation Targets**
-
-| **Target** | **Build** |
-|:---:|:---:|
-| **wasm32-unknown-wasi** |[![Build Status](https://ci.swift.org/job/oss-swift-pr-test-crosscompile-wasm-ubuntu-20_04/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-pr-test-crosscompile-wasm-ubuntu-20_04)|
-
-**Swift Community-Hosted CI Platforms**
-
-| **OS** | **Architecture** | **Build** |
-|---|:---:|:---:|
-|**[Android](https://github.com/swiftlang/swift-community-hosted-continuous-integration/blob/main/nodes/x86_64_ubuntu_24_04_android.json)** | X86_64 |[![Build Status](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-24.04-android-build/lastCompletedBuild/badge/icon)](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-24.04-android-build)|
-|**[Android](https://github.com/swiftlang/swift-community-hosted-continuous-integration/blob/main/nodes/aarch64_ubuntu_24_04_android.json)** | AArch64 |[![Build Status](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-24.04-android-arm64/lastCompletedBuild/badge/icon)](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-24.04-android-arm64)|
-|**[Windows 2019 (VS 2019)](https://github.com/apple/swift-community-hosted-continuous-integration/blob/main/nodes/x86_64_windows_2019_VS2019.json)** | x86_64 | [![Build Status](https://ci-external.swift.org/job/oss-swift-windows-x86_64-vs2019/lastCompletedBuild/badge/icon)](https://ci-external.swift.org/job/oss-swift-windows-x86_64-vs2019)|
+| **OS** | **Status** |
+|---:|:---:|
+| macOS        | [![macOS Universal Build Status](https://ci.swift.org/job/oss-swift-package-macos/lastCompletedBuild/badge/icon?subject=universal)](https://ci.swift.org/job/oss-swift-package-macos)|
+| Ubuntu 20.04 | [![Ubuntu 20.04 x86_64 Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04/lastCompletedBuild/badge/icon?subject=x86_64)](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04) [![Ubuntu 20.04 aarch64 Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04-aarch64/lastCompletedBuild/badge/icon?subject=aarch64)](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04-aarch64)|
+| Ubuntu 22.04 | [![Ubuntu 22.04 x86_64 Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04/lastCompletedBuild/badge/icon?subject=x86_64)](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04) [![Ubuntu 22.04 aarch64 Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04-aarch64/lastCompletedBuild/badge/icon?subject=aarch64)](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04-aarch64)|
+| Ubuntu 24.04 | [![Ubuntu 24.04 x86_64 Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-24_04/lastCompletedBuild/badge/icon?subject=x86_64)](https://ci.swift.org/job/oss-swift-package-ubuntu-24_04) [![Ubuntu 24.04 aarch64 Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-24_04-aarch64/lastCompletedBuild/badge/icon?subject=aarch64)](https://ci.swift.org/job/oss-swift-package-ubuntu-24_04-aarch64)|
+| Amazon Linux 2 | [![Amazon Linux 2 x86_64 Build Status](https://ci.swift.org/job/oss-swift-package-amazon-linux-2/lastCompletedBuild/badge/icon?subject=x86_64)](https://ci.swift.org/job/oss-swift-package-amazon-linux-2) [![Amazon Linux 2 aarch64 Build Status](https://ci.swift.org/job/oss-swift-package-amazon-linux-2-aarch64/lastCompletedBuild/badge/icon?subject=aarch64)](https://ci.swift.org/job/oss-swift-package-amazon-linux-2-aarch64)|
+| Debian 12 | [![Debian 12 x86_64 Build Status](https://ci.swift.org/job/oss-swift-package-debian-12/lastCompletedBuild/badge/icon?subject=x86_64)](https://ci.swift.org/job/oss-swift-package-debian-12) [![Debian 12 aarch64 Build Status](https://ci.swift.org/job/oss-swift-package-debian-12-aarch64/lastCompletedBuild/badge/icon?subject=aarch64)](https://ci.swift.org/job/oss-swift-package-debian-12-aarch64)|
+| Windows 10 | [![Windows 10 x86_64 Build Status](https://ci-external.swift.org/job/swift-main-windows-toolchain/lastCompletedBuild/badge/icon?subject=x86_64)](https://ci-external.swift.org/job/swift-main-windows-toolchain) [![Windows 10 arm64 Build Status](https://ci-external.swift.org/job/swift-main-windows-toolchain-arm64/lastCompletedBuild/badge/icon?subject=arm64)](https://ci-external.swift.org/job/swift-main-windows-toolchain-arm64)|
+| Universal Base Image 9 | [![Universal Base Image 9 x86_64 Build Status](https://ci.swift.org/job/oss-swift-package-ubi-9/lastCompletedBuild/badge/icon?subject=x86_64)](https://ci.swift.org/job/oss-swift-package-ubi-9)|
+|**Cross-Compilation Targets**||
+| wasm32-unknown-wasi |[![wasm32-unknown-wasi Build Status](https://ci.swift.org/job/oss-swift-pr-test-crosscompile-wasm-ubuntu-20_04/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-pr-test-crosscompile-wasm-ubuntu-20_04)|
+|**Community-Hosted CI Platforms**||
+|[Android](https://github.com/swiftlang/swift-community-hosted-continuous-integration/blob/main/nodes/x86_64_ubuntu_24_04_android.json) | [![Android x86_64 Build Status](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-24.04-android-build/lastCompletedBuild/badge/icon?subject=x86_64)](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-24.04-android-build) [![Android aarch64 Build Status](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-24.04-android-arm64/lastCompletedBuild/badge/icon?subject=aarch64)](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-24.04-android-arm64)|
 
 ## Welcome to Swift
 
diff --git a/Runtimes/Core/CMakeLists.txt b/Runtimes/Core/CMakeLists.txt
index 3f1e73c9fa84b..a6428b6b425ab 100644
--- a/Runtimes/Core/CMakeLists.txt
+++ b/Runtimes/Core/CMakeLists.txt
@@ -21,15 +21,16 @@
 
 # TODO:
 # Platform support:
-#   - Work on/Verify cross-compiling
-#   - Work on/Verify Windows and Linux native builds
+#   - Work on/Verify Linux native builds
 # Embedded
 #   -- -Xfrontend -emit-empty-object-file
-# Catalyst Support
-#   -- Will need shadow invocations to generate swiftmodules for Swift parts
-# Install *.abi.json, swiftdoc, and swiftsourceinfo
 
 cmake_minimum_required(VERSION 3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
 
 set(CMAKE_C_VISIBILITY_PRESET "hidden")
 set(CMAKE_CXX_VISIBILITY_PRESET "hidden")
@@ -38,23 +39,16 @@ set(CMAKE_VISIBILITY_INLINES_HIDDEN YES)
 set(CMAKE_POSITION_INDEPENDENT_CODE YES)
 
 set(SwiftCore_CMAKE_MODULES_DIR "${CMAKE_SOURCE_DIR}/cmake/modules")
-list(APPEND CMAKE_MODULE_PATH ${SwiftCore_CMAKE_MODULES_DIR})
+list(APPEND CMAKE_MODULE_PATH
+  ${SwiftCore_CMAKE_MODULES_DIR}
+  "${CMAKE_SOURCE_DIR}/../cmake/modules")
 
 include(CMakeWorkarounds)
-# NOTE: always use the 3-component style as the expansion as
-# `${PROJECT_VERSION}` will not extend this to the complete form and this can
-# change the behaviour for comparison with non-SemVer compliant parsing. If
-# possible, use the 4-version component as that is used to differentiate the
-# builds of the runtime for Windows.
-if($ENV{BUILD_NUMBER})
-  # NOTE: SxS modules have a limit on each component being [0-65535].
-  # https://learn.microsoft.com/en-us/windows/win32/sbscs/assembly-versions
-  math(EXPR BUILD_NUMBER "$ENV{BUILD_NUMBER} % 65535")
-  set(BUILD_NUMBER ".${BUILD_NUMBER}")
-endif()
+
+include(SwiftProjectVersion)
 project(SwiftCore
   LANGUAGES C CXX Swift
-  VERSION 6.1.0${BUILD_NUMBER})
+  VERSION ${SWIFT_RUNTIME_VERSION})
 
 # The Swift standard library is not intended for use as a sub-library as part of
 # another project. It is tightly coupled with the compiler version.
@@ -78,14 +72,15 @@ set(SwiftCore_VENDOR_MODULE_DIR "${SwiftCore_CMAKE_MODULES_DIR}/vendor"
 include(GNUInstallDirs)
 include(CheckSymbolExists)
 include(CheckIncludeFileCXX)
-include(AvailabilityMacros)
 include(CompilerSettings)
 include(DefaultSettings)
 include(EmitSwiftInterface)
+include(InstallSwiftInterface)
 include(PlatformInfo)
 include(gyb)
 include(ResourceEmbedding)
 include(CatalystSupport)
+include(AvailabilityMacros)
 
 check_symbol_exists("asl_log" "asl.h" SwiftCore_HAS_ASL)
 check_symbol_exists("dladdr" "dlfcn.h" SwiftCore_HAS_DLADDR)
@@ -103,7 +98,6 @@ defaulted_option(SwiftCore_ENABLE_OBJC_INTEROP "Enable runtime ObjC interop")
 defaulted_option(SwiftCore_ENABLE_TYPE_PRINTING "Enable printing type names")
 defaulted_option(SwiftCore_ENABLE_VECTOR_TYPES "Enable vector support")
 defaulted_option(SwiftCore_ENABLE_REFLECTION "Enable runtime support for mirrors and reflection support")
-defaulted_option(SwiftCore_ENABLE_COMMANDLINE_SUPPORT "Enable command line argument support")
 defaulted_option(SwiftCore_ENABLE_RUNTIME_FUNCTION_COUNTERS "Enable runtime function counter support")
 defaulted_option(SwiftCore_ENABLE_STDIN "Enable functions that use stdin support")
 defaulted_option(SwiftCore_ENABLE_ENVIRONMENT "Enable environment variable support")
@@ -114,7 +108,9 @@ defaulted_option(SwiftCore_ENABLE_COMPACT_ABSOLUTE_FUNCTION_POINTERS "Resolve ab
 defaulted_option(SwiftCore_ENABLE_BACKDEPLOYMENT_SUPPORT "Add symbols for runtime backdeployment")
 defaulted_option(SwiftCore_ENABLE_STDLIB_TRACING "Enable tracing in the runtime. Assumes the presence of os_log(3) and the os_signpost(3) API.")
 defaulted_option(SwiftCore_ENABLE_CONCURRENCY "Enable Concurrency runtime support")
+defaulted_option(SwiftCore_ENABLE_REMOTE_MIRROR "Enable RemoteMirror runtime support")
 defaulted_set(SwiftCore_CONCURRENCY_GLOBAL_EXECUTOR STRING "Default Concurrency global executor implementation")
+option(SwiftCore_ENABLE_COMMANDLINE_SUPPORT "Enable command line argument support" ON)
 option(SwiftCore_ENABLE_UNICODE_DATA "Include unicode data in Swift runtimes" ON)
 option(SwiftCore_ENABLE_SHORT_MANGLING_LOOKUPS "Build with fast-path context descriptor lookups based on well-known short manglings." ON)
 option(SwiftCore_ENABLE_FILESYSTEM_SUPPORT "Build for systems that have a filesystem" ON)
@@ -125,6 +121,7 @@ defaulted_option(SwiftCore_ENABLE_BACKTRACING "Enable backtracing runtime suppor
 defaulted_set(SwiftCore_BACKTRACER_PATH STRING "Set a fixed path to the Swift backtracer")
 defaulted_option(SwiftCore_ENABLE_FATALERROR_BACKTRACE "Build stdlib fatalError with backtrace output")
 defaulted_option(SwiftCore_ENABLE_PRESPECIALIZATION "Enable generic metadata prespecialization")
+defaulted_option(SwiftCore_ENABLE_STRICT_AVAILABILITY "Enable strict availability; this will cause things to break at desk or in CI if the host OS is a lower version than some `@availability` annotations in the runtime code")
 
 option(SwiftCore_ENABLE_CLOBBER_FREED_OBJECTS "" OFF)
 option(SwiftCore_ENABLE_RUNTIME_LEAK_CHECKER "" OFF)
@@ -159,7 +156,7 @@ add_compile_definitions(
   $<$<BOOL:${SwiftCore_HAS_DARWIN_LIBMALLOC}>:-DSWIFT_STDLIB_HAS_DARWIN_LIBMALLOC> # Anything that includes include/swift/Runtime/Config.h
   $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_THREADING_${SwiftCore_THREADING_PACKAGE}>
   $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_RUNTIME_ENABLE_LEAK_CHECKER=$<BOOL:${SwiftCore_ENABLE_RUNTIME_LEAK_CHECKER}>>
-  $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_RUNTIME_CLOBBER_FREED_OBJECTS=$<BOOL:${SwiftCore_ENABLE_CLOBBER_FREED_OBJECTS}>>)
+  $<$<BOOL:${SwiftCore_ENABLE_CLOBBER_FREED_OBJECTS}>:-DSWIFT_RUNTIME_CLOBBER_FREED_OBJECTS>)
 
 add_compile_options(
   $<$<COMPILE_LANGUAGE:CXX>:-fno-rtti>
@@ -174,6 +171,8 @@ add_compile_options(
 # frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
 # a compromise, treat all linker warnings as errors.
 add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Android,Linux>:LINKER:-z,defs>)
 
 add_compile_options(
   $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>
@@ -190,7 +189,6 @@ add_compile_options(
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>"
   "$<$<COMPILE_LANGUAGE:Swift>:-no-link-objc-runtime>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enforce-exclusivity=unchecked>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-ossa-modules>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -empty-abi-descriptor>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
   "$<$<AND:$<NOT:$<BOOL:${SwiftCore_ENABLE_OBJC_INTEROP}>>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -disable-objc-interop>"
@@ -208,14 +206,20 @@ add_subdirectory(Demangling)
 add_subdirectory(Threading)
 add_subdirectory(runtime)
 add_subdirectory(stubs)
-add_subdirectory(CommandLineSupport)
 add_subdirectory(core)
+if(SwiftCore_ENABLE_COMMANDLINE_SUPPORT)
+  add_subdirectory(CommandLineSupport)
+endif()
 if(SwiftCore_ENABLE_ONONESUPPORT)
   add_subdirectory(SwiftOnoneSupport)
 endif()
 if(SwiftCore_ENABLE_CONCURRENCY)
   add_subdirectory(Concurrency)
 endif()
+if(SwiftCore_ENABLE_REMOTE_MIRROR)
+  add_subdirectory(RemoteInspection)
+  add_subdirectory(SwiftRemoteMirror)
+endif()
 
 # Inter-project install info
 export(EXPORT SwiftCoreTargets
diff --git a/Runtimes/Core/CommandLineSupport/CMakeLists.txt b/Runtimes/Core/CommandLineSupport/CMakeLists.txt
index fa53462384b44..df8dd70c135c7 100644
--- a/Runtimes/Core/CommandLineSupport/CMakeLists.txt
+++ b/Runtimes/Core/CommandLineSupport/CMakeLists.txt
@@ -1,17 +1,9 @@
-if(SwiftCore_ENABLE_COMMANDLINE_SUPPORT)
-  add_library(swiftCommandLineSupport STATIC CommandLine.cpp)
-  target_include_directories(swiftCommandLineSupport PRIVATE
-    "${SwiftCore_SWIFTC_SOURCE_DIR}/include"
-    "${PROJECT_BINARY_DIR}/include")
-  target_compile_definitions(swiftCommandLineSupport PUBLIC
-    -DSWIFT_STDLIB_HAS_COMMANDLINE)
-
-  target_link_libraries(swiftCommandLineSupport PRIVATE
-    swiftShims)
-
-  if(NOT BUILD_SHARED_LIBS)
-    install(TARGETS swiftCommandLineSupport
-      EXPORT SwiftCoreTargets
-      COMPONENT SwiftCore_runtime)
-  endif()
-endif()
+# TODO(etcwilde) migrate this into subdir subdirectory once the migration is
+# completed.
+target_sources(swiftCore PRIVATE
+  CommandLine.cpp)
+target_compile_definitions(swiftCore PUBLIC
+  -DSWIFT_STDLIB_HAS_COMMANDLINE)
+target_include_directories(swiftCore PRIVATE
+  "${SwiftCore_SWIFTC_SOURCE_DIR}/include"
+  "${PROJECT_BINARY_DIR}/include")
diff --git a/Runtimes/Core/Concurrency/CMakeLists.txt b/Runtimes/Core/Concurrency/CMakeLists.txt
index 8dd89783d7ac2..6ea008aecdd73 100644
--- a/Runtimes/Core/Concurrency/CMakeLists.txt
+++ b/Runtimes/Core/Concurrency/CMakeLists.txt
@@ -1,7 +1,8 @@
 add_subdirectory(InternalShims)
 
+gyb_expand(Task+init.swift.gyb Task+init.swift)
 gyb_expand(TaskGroup+addTask.swift.gyb TaskGroup+addTask.swift)
-gyb_expand(Task+startSynchronously.swift.gyb Task+startSynchronously.swift)
+gyb_expand(Task+immediate.swift.gyb Task+immediate.swift)
 
 add_library(swift_Concurrency
   Actor.cpp
@@ -12,9 +13,9 @@ add_library(swift_Concurrency
   EmbeddedSupport.cpp
   Error.cpp
   ExecutorBridge.cpp
+  ExecutorImpl.cpp
   ExecutorChecks.cpp
   GlobalExecutor.cpp
-  Setup.cpp
   Task.cpp
   TaskAlloc.cpp
   TaskGroup.cpp
@@ -23,7 +24,7 @@ add_library(swift_Concurrency
   ThreadingError.cpp
   TracingSignpost.cpp
   "${PROJECT_SOURCE_DIR}/CompatibilityOverride/CompatibilityOverride.cpp"
-  "${PROJECT_SOURCE_DIR}/linker-support/magic-symbols-for-install-name.c"
+  "./linker-support/magic-symbols-for-install-name.c"
   Actor.swift
   AsyncCompactMapSequence.swift
   AsyncDropFirstSequence.swift
@@ -69,7 +70,6 @@ add_library(swift_Concurrency
   Deque/Deque+UnsafeHandle.swift
   Deque/UnsafeMutableBufferPointer+Utilities.swift
   DiscardingTaskGroup.swift
-  DummyExecutor.swift
   Errors.swift
   Executor.swift
   ExecutorAssertions.swift
@@ -80,6 +80,8 @@ add_library(swift_Concurrency
   PartialAsyncTask.swift
   PlatformExecutorDarwin.swift
   PlatformExecutorLinux.swift
+  PlatformExecutorFreeBSD.swift
+  PlatformExecutorOpenBSD.swift
   PlatformExecutorWindows.swift
   PriorityQueue.swift
   SourceCompatibilityShims.swift
@@ -89,15 +91,23 @@ add_library(swift_Concurrency
   Task+TaskExecutor.swift
   TaskCancellation.swift
   TaskGroup.swift
-  TaskGroup+Embedded.swift
   TaskLocal.swift
   TaskSleep.swift
   TaskSleepDuration.swift
+  UnimplementedExecutor.swift
+  "${CMAKE_CURRENT_BINARY_DIR}/Task+init.swift"
   "${CMAKE_CURRENT_BINARY_DIR}/TaskGroup+addTask.swift"
-  "${CMAKE_CURRENT_BINARY_DIR}/Task+startSynchronously.swift")
+  "${CMAKE_CURRENT_BINARY_DIR}/Task+immediate.swift")
+
+if(APPLE)
+  target_sources(swift_Concurrency PRIVATE
+    CFExecutor.swift
+    CFExecutor.cpp)
+endif()
 
 include(${SwiftCore_CONCURRENCY_GLOBAL_EXECUTOR}.cmake)
 target_compile_definitions(swift_Concurrency PRIVATE
+  $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_RUNTIME>
   $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_TARGET_LIBRARY_NAME=swift_Concurrency>
   # NOTE: VS2017 <15.8 would round clamp alignment to alignof(max_align_t) which
   # was non-conformant. Indicate that we wish to use extended alignment.
@@ -108,6 +118,7 @@ target_compile_options(swift_Concurrency PRIVATE
   # NOTE: do not remove until `IsolatedAny` is on by default in all supported
   # compilers.
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature IsolatedAny>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Extern>"
   # NOTE: enable the async frame pointer on Darwin to faciliate debugging.
   $<$<AND:$<PLATFORM_ID:Darwin>,$<COMPILE_LANGUAGE:C,CXX>>:-fswift-async-fp=always>
   "$<$<AND:$<PLATFORM_ID:Darwin>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -swift-async-frame-pointer=always>"
@@ -118,10 +129,14 @@ target_include_directories(swift_Concurrency PRIVATE
   # FIXME: grant access to `runtime/CMakeConfig.h` which should be available
   # through the swiftRuntime target.
   "${PROJECT_BINARY_DIR}/include")
+# FIXME: Why is this not implicitly in the interface flags?
+target_include_directories(swift_Concurrency INTERFACE
+  "$<$<COMPILE_LANGUAGE:Swift>:$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>$<INSTALL_INTERFACE:$<INSTALL_PREFIX>/${SwiftCore_INSTALL_SWIFTMODULEDIR}>>")
 target_link_libraries(swift_Concurrency PRIVATE
   swiftShims
   swiftConcurrencyInternalShims
   $<$<BOOL:${BUILD_SHARED_LIBS}>:swiftThreading>
+  $<$<PLATFORM_ID:Android>:log>
   $<$<PLATFORM_ID:Windows>:Synchronization>
   $<$<PLATFORM_ID:Windows>:mincore>
   # Link to the runtime that we are just building.
@@ -129,6 +144,10 @@ target_link_libraries(swift_Concurrency PRIVATE
 set_target_properties(swift_Concurrency PROPERTIES
   Swift_MODULE_NAME _Concurrency
   LINKER_LANGUAGE CXX)
+if(NOT BUILD_SHARED_LIBS AND CMAKE_STATIC_LIBRARY_PREFIX_Swift)
+  set_target_properties(swift_Concurrency PROPERTIES
+    PREFIX ${CMAKE_STATIC_LIBRARY_PREFIX_Swift})
+endif()
 
 install(TARGETS swift_Concurrency
   EXPORT SwiftCoreTargets
@@ -138,3 +157,7 @@ install(TARGETS swift_Concurrency
   RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
 emit_swift_interface(swift_Concurrency)
 install_swift_interface(swift_Concurrency)
+
+# Configure plist creation for Darwin platforms.
+generate_plist(swift_Concurrency "${CMAKE_PROJECT_VERSION}" swift_Concurrency)
+embed_manifest(swift_Concurrency)
diff --git a/Runtimes/Core/Concurrency/dispatch.cmake b/Runtimes/Core/Concurrency/dispatch.cmake
index 4d04b582a3b4c..49dee81c3654d 100644
--- a/Runtimes/Core/Concurrency/dispatch.cmake
+++ b/Runtimes/Core/Concurrency/dispatch.cmake
@@ -1,12 +1,16 @@
 
 find_package(dispatch QUIET REQUIRED)
 
+check_symbol_exists("dispatch_async_swift_job" "dispatch/private.h"
+  SwiftConcurrency_HAS_DISPATCH_ASYNC_SWIFT_JOB)
+
 target_sources(swift_Concurrency PRIVATE
   DispatchGlobalExecutor.cpp
   DispatchExecutor.swift
   CFExecutor.swift
   ExecutorImpl.swift)
 target_compile_definitions(swift_Concurrency PRIVATE
+  $<$<BOOL:${SwiftConcurrency_HAS_DISPATCH_ASYNC_SWIFT_JOB}>:-DSwiftConcurrency_HAS_DISPATCH_ASYNC_SWIFT_JOB=1>
   $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_CONCURRENCY_USES_DISPATCH=1>)
 target_compile_options(swift_Concurrency PRIVATE
   $<$<COMPILE_LANGUAGE:Swift>:-DSWIFT_CONCURRENCY_USES_DISPATCH>
diff --git a/Runtimes/Core/Demangling/CMakeLists.txt b/Runtimes/Core/Demangling/CMakeLists.txt
index f246c29567366..0ade7ee08aa8f 100644
--- a/Runtimes/Core/Demangling/CMakeLists.txt
+++ b/Runtimes/Core/Demangling/CMakeLists.txt
@@ -21,7 +21,8 @@ target_compile_definitions(swiftDemangling PRIVATE
 # compiler, in order to avoid possible ODR violations if both are statically
 # linked into the same binary. (see also commit message for 5b1daa9055c99904c84862ecc313641fd9b26e63)
 target_compile_definitions(swiftDemangling PUBLIC
-    $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_INLINE_NAMESPACE=__runtime>)
+  -DSWIFT_RUNTIME
+  $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_INLINE_NAMESPACE=__runtime>)
 
 target_include_directories(swiftDemangling
   PRIVATE
diff --git a/Runtimes/Core/LLVMSupport/CMakeLists.txt b/Runtimes/Core/LLVMSupport/CMakeLists.txt
index 92e8f651da752..3374c94aa0ac2 100644
--- a/Runtimes/Core/LLVMSupport/CMakeLists.txt
+++ b/Runtimes/Core/LLVMSupport/CMakeLists.txt
@@ -5,9 +5,10 @@ add_library(swiftLLVMSupport OBJECT
   SmallPtrSet.cpp
   SmallVector.cpp
   StringRef.cpp)
-target_compile_options(swiftLLVMSupport
-  PRIVATE
-    $<$<BOOL:${SwiftCore_HAS_ASL}>:-DSWIFT_STDLIB_HAS_ASL>)
+target_compile_options(swiftLLVMSupport PRIVATE
+  $<$<BOOL:${SwiftCore_HAS_ASL}>:-DSWIFT_STDLIB_HAS_ASL>)
+target_link_libraries(swiftLLVMSupport PRIVATE
+  $<$<PLATFORM_ID:Android>:log>)
 
 if(NOT BUILD_SHARED_LIBS)
   install(TARGETS swiftLLVMSupport
diff --git a/Runtimes/Core/RemoteInspection/CMakeLists.txt b/Runtimes/Core/RemoteInspection/CMakeLists.txt
new file mode 100644
index 0000000000000..9e2e01290958a
--- /dev/null
+++ b/Runtimes/Core/RemoteInspection/CMakeLists.txt
@@ -0,0 +1,24 @@
+
+add_library(swiftRemoteInspection OBJECT
+  MetadataSource.cpp
+  TypeLowering.cpp
+  TypeRef.cpp
+  TypeRefBuilder.cpp)
+target_compile_definitions(swiftRemoteInspection PRIVATE
+  $<$<BOOL:${SwiftCore_ENABLE_REFLECTION}>:SWIFT_ENABLE_REFLECTION>)
+target_include_directories(swiftRemoteInspection PRIVATE
+  "${PROJECT_BINARY_DIR}/include"
+  "${SwiftCore_SWIFTC_SOURCE_DIR}/include")
+target_include_directories(swiftRemoteInspection PUBLIC
+  "$<BUILD_INTERFACE:${SwiftCore_SWIFTC_SOURCE_DIR}/include/swift/RemoteInspection/RuntimeHeaders>")
+target_link_libraries(swiftRemoteInspection PRIVATE
+  swiftDemangling
+  $<$<BOOL:${SwiftCore_ENABLE_CRASH_REPORTER_CLIENT}>:swiftDemanglingCR>
+  swiftLLVMSupport
+  swiftShims)
+
+if(NOT BUILD_SHARED_LIBS)
+  install(TARGETS swiftRemoteInspection
+    EXPORT SwiftCoreTargets
+    COMPONENT SwiftCore_runtime)
+endif()
diff --git a/Runtimes/Core/SwiftOnoneSupport/CMakeLists.txt b/Runtimes/Core/SwiftOnoneSupport/CMakeLists.txt
index 2ec1d95048f4c..41005c11d5b37 100644
--- a/Runtimes/Core/SwiftOnoneSupport/CMakeLists.txt
+++ b/Runtimes/Core/SwiftOnoneSupport/CMakeLists.txt
@@ -41,4 +41,5 @@ emit_swift_interface(swiftSwiftOnoneSupport)
 install_swift_interface(swiftSwiftOnoneSupport)
 
 # Configure plist creation for Darwin platforms.
-generate_plist("${CMAKE_PROJECT_NAME}" "${CMAKE_PROJECT_VERSION}" swiftSwiftOnoneSupport)
+generate_plist(swiftSwiftOnoneSupport "${CMAKE_PROJECT_VERSION}" swiftSwiftOnoneSupport)
+embed_manifest(swiftSwiftOnoneSupport)
diff --git a/Runtimes/Core/SwiftRemoteMirror/CMakeLists.txt b/Runtimes/Core/SwiftRemoteMirror/CMakeLists.txt
new file mode 100644
index 0000000000000..1b0341e55fb3d
--- /dev/null
+++ b/Runtimes/Core/SwiftRemoteMirror/CMakeLists.txt
@@ -0,0 +1,35 @@
+
+add_library(swiftRemoteMirror
+  SwiftRemoteMirror.cpp)
+target_compile_definitions(swiftRemoteMirror PUBLIC
+  $<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:swiftRemoteMirror_STATIC>)
+target_link_libraries(swiftRemoteMirror PRIVATE
+  swiftRemoteInspection)
+target_include_directories(swiftRemoteMirror PRIVATE
+  "${PROJECT_BINARY_DIR}/include"
+  "${SwiftCore_SWIFTC_SOURCE_DIR}/include")
+target_link_libraries(swiftRemoteMirror PRIVATE
+  # FIXME(compnerd) why is this required? These should be transitively applied
+  # from `swiftRemoteInspection`
+  swiftDemangling
+  $<$<BOOL:${SwiftCore_ENABLE_CRASH_REPORTER_CLIENT}>:swiftDemanglingCR>
+  swiftLLVMSupport
+  swiftShims)
+
+install(TARGETS swiftRemoteMirror
+    EXPORT SwiftCoreTargets
+    COMPONENT SwiftCore_runtime
+    ARCHIVE DESTINATION "${SwiftCore_INSTALL_LIBDIR}"
+    LIBRARY DESTINATION "${SwiftCore_INSTALL_LIBDIR}"
+    RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+install(FILES
+  ${SwiftCore_SWIFTC_SOURCE_DIR}/include/swift/SwiftRemoteMirror/MemoryReaderInterface.h
+  ${SwiftCore_SWIFTC_SOURCE_DIR}/include/swift/SwiftRemoteMirror/Platform.h
+  ${SwiftCore_SWIFTC_SOURCE_DIR}/include/swift/SwiftRemoteMirror/SwiftRemoteMirror.h
+  ${SwiftCore_SWIFTC_SOURCE_DIR}/include/swift/SwiftRemoteMirror/SwiftRemoteMirrorTypes.h
+  ${SwiftCore_SWIFTC_SOURCE_DIR}/include/swift/SwiftRemoteMirror/module.modulemap
+  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/swift/SwiftRemoteMirror")
+
+# Configure plist creation for Darwin platforms.
+generate_plist("${CMAKE_PROJECT_NAME}" "${CMAKE_PROJECT_VERSION}" swiftRemoteMirror)
+embed_manifest(swiftRemoteMirror)
diff --git a/Runtimes/Core/cmake/caches/Vendors/Apple/apple-common.cmake b/Runtimes/Core/cmake/caches/Vendors/Apple/apple-common.cmake
index 4a921adfa6b0c..abf1ecbb46827 100644
--- a/Runtimes/Core/cmake/caches/Vendors/Apple/apple-common.cmake
+++ b/Runtimes/Core/cmake/caches/Vendors/Apple/apple-common.cmake
@@ -12,6 +12,8 @@ set(SwiftCore_ENABLE_VECTOR_TYPES ON CACHE BOOL "")
 set(SwiftCore_ENABLE_RUNTIME_FUNCTION_COUNTERS ON CACHE BOOL "")
 set(SwiftCore_ENABLE_BACKDEPLOYMENT_SUPPORT ON CACHE BOOL "")
 set(SwiftCore_ENABLE_FILESYSTEM_SUPPORT ON CACHE BOOL "")
+set(SwiftCore_ENABLE_STRICT_AVAILABILITY ON CACHE BOOL "")
+
 set(SwiftCore_OPTIMIZATION_REMARKS "bitstream" CACHE STRING "")
 
 set(SwiftCore_INSTALL_NESTED_SUBDIR OFF CACHE BOOL "")
diff --git a/Runtimes/Core/cmake/interface/SwiftCoreConfig.cmake.in b/Runtimes/Core/cmake/interface/SwiftCoreConfig.cmake.in
index 40a5469e08589..f6e2f73333873 100644
--- a/Runtimes/Core/cmake/interface/SwiftCoreConfig.cmake.in
+++ b/Runtimes/Core/cmake/interface/SwiftCoreConfig.cmake.in
@@ -4,3 +4,5 @@ include("${CMAKE_CURRENT_LIST_DIR}/SwiftCoreTargets.cmake")
 set(SwiftCore_ENABLE_LIBRARY_EVOLUTION @SwiftCore_ENABLE_LIBRARY_EVOLUTION@)
 
 set(SwiftCore_ENABLE_VECTOR_TYPES @SwiftCore_ENABLE_VECTOR_TYPES@)
+
+set(SwiftCore_ENABLE_BACKDEPLOYMENT_SUPPORT @SwiftCore_ENABLE_BACKDEPLOYMENT_SUPPORT@)
diff --git a/Runtimes/Core/cmake/modules/AvailabilityMacros.cmake b/Runtimes/Core/cmake/modules/AvailabilityMacros.cmake
index b1dd4920c6b80..5f3f21985ef9e 100644
--- a/Runtimes/Core/cmake/modules/AvailabilityMacros.cmake
+++ b/Runtimes/Core/cmake/modules/AvailabilityMacros.cmake
@@ -1,5 +1,42 @@
-file(STRINGS "${SwiftCore_SWIFTC_SOURCE_DIR}/utils/availability-macros.def" availability_defs)
+configure_file("${SwiftCore_SWIFTC_SOURCE_DIR}/utils/availability-macros.def"
+               "${CMAKE_CURRENT_BINARY_DIR}/availability-macros.def"
+               COPYONLY)
+file(STRINGS "${CMAKE_CURRENT_BINARY_DIR}/availability-macros.def" availability_defs)
 list(FILTER availability_defs EXCLUDE REGEX "^\\s*(#.*)?$")
 foreach(def ${availability_defs})
-  add_compile_options("$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -define-availability -Xfrontend \"${def}\">")
+  list(APPEND availability_definitions "-Xfrontend -define-availability -Xfrontend \"${def}\"")
+
+  if("${def}" MATCHES "SwiftStdlib .*")
+    # For each SwiftStdlib x.y, also define StdlibDeploymentTarget x.y, which,
+    # will expand to the current `-target` platform if the macro defines a
+    # newer platform as its availability.
+    #
+    # There is a setting, SwiftCore_ENABLE_STRICT_AVAILABILITY, which if set
+    # ON will cause us to use the "proper" availability instead.
+    string(REPLACE "SwiftStdlib" "StdlibDeploymentTarget" current "${def}")
+    if(NOT SwiftCore_ENABLE_STRICT_AVAILABILITY AND SwiftCore_SWIFT_AVAILABILITY_PLATFORM)
+      if("${SwiftCore_SWIFT_AVAILABILITY_PLATFORM}" STREQUAL "macOS" AND "${SwiftCore_VARIANT_AVAILABILITY_PLATFORM}" STREQUAL "iOS")
+        string(REGEX MATCH "iOS ([0-9]+(\.[0-9]+)+)" ios_platform_version "${def}")
+        string(REGEX MATCH "[0-9]+(\.[0-9]+)+" ios_version "${ios_platform_version}")
+        string(REGEX MATCH "macOS ([0-9]+(\.[0-9]+)+)" macos_platform_version "${def}")
+        string(REGEX MATCH "[0-9]+(\.[0-9]+)+" macos_version "${macos_platform_version}")
+        if((NOT macos_version STREQUAL "9999" OR NOT ios_version STREQUAL "9999") AND (macos_version VERSION_GREATER CMAKE_OSX_DEPLOYMENT_TARGET OR ios_version VERSION_GREATER SwiftCore_VARIANT_DEPLOYMENT_VERSION))
+          string(REGEX REPLACE ":.*" ": macOS ${CMAKE_OSX_DEPLOYMENT_VERSION}, iOS ${SwiftCore_VARIANT_DEPLOYMENT_VERSION}" current "${current}")
+        endif()
+      else()
+        string(REGEX MATCH "${SwiftCore_SWIFT_AVAILABILITY_PLATFORM} ([0-9]+(\.[0-9]+)+)" platform_version "${def}")
+        string(REGEX MATCH "[0-9]+(\.[0-9]+)+" version "${platform_version}")
+        if(NOT version STREQUAL "9999" AND version VERSION_GREATER CMAKE_OSX_DEPLOYMENT_TARGET)
+          string(REGEX REPLACE ":.*" ":${SwiftCore_SWIFT_AVAILABILITY_PLATFORM} ${CMAKE_OSX_DEPLOYMENT_TARGET}" current "${current}")
+        endif()
+      endif()
+    endif()
+    list(APPEND availability_definitions "-Xfrontend -define-availability -Xfrontend \"${current}\"")
+  endif()
 endforeach()
+
+list(JOIN availability_definitions "\n" availability_definitions)
+file(GENERATE
+  OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/availability-macros.rsp"
+  CONTENT "${availability_definitions}")
+add_compile_options("$<$<COMPILE_LANGUAGE:Swift>:SHELL:${CMAKE_Swift_RESPONSE_FILE_FLAG}${CMAKE_CURRENT_BINARY_DIR}/availability-macros.rsp>")
diff --git a/Runtimes/Core/cmake/modules/CatalystSupport.cmake b/Runtimes/Core/cmake/modules/CatalystSupport.cmake
index 7f761007414ea..3e331b81ed9b5 100644
--- a/Runtimes/Core/cmake/modules/CatalystSupport.cmake
+++ b/Runtimes/Core/cmake/modules/CatalystSupport.cmake
@@ -34,5 +34,20 @@ if(SwiftCore_COMPILER_VARIANT_TARGET)
     set(SwiftCore_VARIANT_MODULE_TRIPLE "${module_triple}" CACHE STRING "Triple used for installed swift{module,interface} files for the target variant")
     mark_as_advanced(SwiftCore_VARIANT_MODULE_TRIPLE)
     message(CONFIGURE_LOG "Swift target variant module triple: ${module_triple}")
+
+    string(JSON triple GET "${target_info_json}" "target" "triple")
+    if(triple MATCHES "apple-([a-zA-Z]+)([0-9]+[.0-9]*)-macabi")
+      set(SwiftCore_VARIANT_DEPLOYMENT_VERSION "${CMAKE_MATCH_2}")
+      mark_as_advanced(SwiftCore_VARIANT_DEPLOYMENT_VERSION)
+      message(CONFIGURE_LOG "Swift target variant deployment version: ${SwiftCore_VARIANT_DEPLOYMENT_VERSION}")
+    endif()
+  endif()
+
+  if(SwiftCore_EXPERIMENTAL_EMIT_VARIANT_MODULE)
+    check_compiler_flag(Swift "-experimental-emit-variant-module" HAVE_Swift_EMIT_VARIANT_MODULE_FLAG)
+    if(HAVE_Swift_EMIT_VARIANT_MODULE_FLAG)
+    add_compile_options(
+        "$<$<COMPILE_LANGUAGE:Swift>:-experimental-emit-variant-module>")
+    endif()
   endif()
 endif()
diff --git a/Runtimes/Core/cmake/modules/DefaultSettings.cmake b/Runtimes/Core/cmake/modules/DefaultSettings.cmake
index e6fc1f5820ef0..e7a590054857f 100644
--- a/Runtimes/Core/cmake/modules/DefaultSettings.cmake
+++ b/Runtimes/Core/cmake/modules/DefaultSettings.cmake
@@ -6,11 +6,12 @@
 # the variable with `-DSwiftCore_*` on the commandline.
 
 set(SwiftCore_ENABLE_BACKTRACING_default OFF) # TODO: enable this by default
-set(SwiftCore_ENABLE_COMMANDLINE_SUPPORT_default OFF) # TODO: enable this by default
 
 set(SwiftCore_ENABLE_STDIN_default ON)
 set(SwiftCore_ENABLE_TYPE_PRINTING_default ON)
 
+set(SwiftCore_ENABLE_STRICT_AVAILABILITY_default OFF)
+
 set(SwiftCore_BACKTRACER_PATH_default "")
 
 # Provide a boolean option that a user can optionally enable.
@@ -20,7 +21,7 @@ macro(defaulted_option variable helptext)
   if(NOT DEFINED ${variable}_default)
     set(${variable}_default OFF)
   endif()
-  option(${variable} ${helptext} ${${variable}_default})
+  option(${variable} "${helptext}" ${${variable}_default})
 endmacro()
 
 # Create a defaulted cache entry
@@ -41,6 +42,7 @@ if(APPLE)
   set(SwiftCore_ENABLE_RUNTIME_OS_VERSIONING_default ON)
   set(SwiftCore_ENABLE_OVERRIDABLE_RETAIN_RELEASE_default ON)
   set(SwiftCore_ENABLE_CONCURRENCY_default NO)
+  set(SwiftCore_ENABLE_REMOTE_MIRROR_default NO)
   set(SwiftCore_THREADING_PACKAGE_default "DARWIN")
   set(SwiftCore_ENABLE_PRESPECIALIZATION_default ON)
   set(SwiftCore_CONCURRENCY_GLOBAL_EXECUTOR_default "dispatch")
@@ -48,9 +50,12 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL "WASM")
   set(SwiftCore_OBJECT_FORMAT_default "elf")
   set(SwiftCore_THREADING_PACKAGE_default "NONE")
   set(SwiftCore_ENABLE_CONCURRENCY_default NO)
+  set(SwiftCore_ENABLE_REMOTE_MIRROR_default NO)
   set(SwiftCore_CONCURRENCY_GLOBAL_EXECUTOR_default "none")
 elseif(LINUX OR ANDROID OR BSD)
   set(SwiftCore_OBJECT_FORMAT_default "elf")
+
+  set(SwiftCore_ENABLE_REFLECTION_default ON)
   set(SwiftCore_ENABLE_FATALERROR_BACKTRACE_default ON)
   if(LINUX)
     set(SwiftCore_THREADING_PACKAGE_default "LINUX")
@@ -59,15 +64,26 @@ elseif(LINUX OR ANDROID OR BSD)
     set(SwiftCore_THREADING_PACKAGE_default "PTHREADS")
   endif()
   set(SwiftCore_ENABLE_CONCURRENCY_default NO)
+  set(SwiftCore_ENABLE_REMOTE_MIRROR_default NO)
   set(SwiftCore_CONCURRENCY_GLOBAL_EXECUTOR_default "dispatch")
 elseif(WIN32)
   set(SwiftCore_OBJECT_FORMAT_default "coff")
+
+  set(SwiftCore_ENABLE_LIBRARY_EVOLUTION_default ${BUILD_SHARED_LIBS})
   set(SwiftCore_ENABLE_REFLECTION_default ON)
   set(SwiftCore_ENABLE_FATALERROR_BACKTRACE_default ON)
+  set(SwiftCore_ENABLE_OVERRIDABLE_RETAIN_RELEASE_default ON)
   set(SwiftCore_ENABLE_CONCURRENCY_default NO)
+  set(SwiftCore_ENABLE_REMOTE_MIRROR_default NO)
   set(SwiftCore_THREADING_PACKAGE_default "WIN32")
-  set(SwiftCore_ENABLE_PRESPECIALIZATION_default ON)
+  # FIXME(swiftlang/swift#84780) - generic prespecialization seems to cause
+  # errors
+  set(SwiftCore_ENABLE_PRESPECIALIZATION_default OFF)
   set(SwiftCore_CONCURRENCY_GLOBAL_EXECUTOR_default "dispatch")
+
+  set(SwiftCore_ENABLE_VECTOR_TYPES_default ON)
+  set(SwiftCore_ENABLE_FILESYSTEM_SUPPORT_default ON)
+  set(SwiftCore_INSTALL_NESTED_SUBDIR_default ON)
 endif()
 
 include("${SwiftCore_VENDOR_MODULE_DIR}/DefaultSettings.cmake" OPTIONAL)
diff --git a/Runtimes/Core/cmake/modules/DetectedPlatformInfo.cmake.in b/Runtimes/Core/cmake/modules/DetectedPlatformInfo.cmake.in
new file mode 100644
index 0000000000000..7833ade0e49ba
--- /dev/null
+++ b/Runtimes/Core/cmake/modules/DetectedPlatformInfo.cmake.in
@@ -0,0 +1,8 @@
+set(SwiftCore_SIZEOF_POINTER @SwiftCore_SIZEOF_POINTER@)
+set(SwiftCore_MODULE_TRIPLE @SwiftCore_MODULE_TRIPLE@)
+set(SwiftCore_PLATFORM_SUBIDR @SwiftCore_PLATFORM_SUBIDR@)
+set(SwiftCore_ARCH_SUBDIR @SwiftCore_ARCH_SUBDIR@)
+
+set(SwiftCore_SWIFT_AVAILABILITY_PLATFORM @SwiftCore_SWIFT_AVAILABILITY_PLATFORM@)
+
+set(SwiftCore_PLATFORM_INFO_SET 1)
diff --git a/Runtimes/Core/cmake/modules/EmitSwiftInterface.cmake b/Runtimes/Core/cmake/modules/EmitSwiftInterface.cmake
index 88cf2427a68f5..fc8f9c4c3eae2 100644
--- a/Runtimes/Core/cmake/modules/EmitSwiftInterface.cmake
+++ b/Runtimes/Core/cmake/modules/EmitSwiftInterface.cmake
@@ -8,66 +8,61 @@
 function(emit_swift_interface target)
   # Generate the target-variant binary swift module when performing zippered
   # build
+  # Clean this up once CMake has nested swiftmodules in the build directory:
+  # https://gitlab.kitware.com/cmake/cmake/-/merge_requests/10664
+  # https://cmake.org/cmake/help/git-stage/policy/CMP0195.html
+
+  # We can't expand the Swift_MODULE_NAME target property in a generator
+  # expression or it will fail saying that the target doesn't exist.
+  get_target_property(module_name ${target} Swift_MODULE_NAME)
+  if(NOT module_name)
+    set(module_name ${target})
+  endif()
+  set(module_directory "${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule")
+  # Account for an existing swiftmodule file
+  # generated with the previous logic
+  if(EXISTS "${module_directory}" AND NOT IS_DIRECTORY "${module_directory}")
+    message(STATUS "Removing regular file ${module_directory} to support nested swiftmodule generation")
+    file(REMOVE "${module_directory}")
+  endif()
+  target_compile_options(${target} PRIVATE
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-module-path ${module_directory}/${SwiftCore_MODULE_TRIPLE}.swiftmodule>")
+  set_property(TARGET "${target}" APPEND PROPERTY ADDITIONAL_CLEAN_FILES
+    "${module_directory}/${SwiftCore_MODULE_TRIPLE}.swiftmodule"
+    "${module_directory}/${SwiftCore_MODULE_TRIPLE}.swiftdoc"
+    "${module_directory}/${SwiftCore_MODULE_TRIPLE}.swiftsourceinfo")
   if(SwiftCore_VARIANT_MODULE_TRIPLE)
-    set(variant_module_tmp_dir "${CMAKE_CURRENT_BINARY_DIR}/${target}-${SwiftCore_VARIANT_MODULE_TRIPLE}")
-    file(MAKE_DIRECTORY "${variant_module_tmp_dir}")
     target_compile_options(${target} PRIVATE
-      "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-path ${variant_module_tmp_dir}/${target}.swiftmodule>")
+      "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-path ${module_directory}/${SwiftCore_VARIANT_MODULE_TRIPLE}.swiftmodule>")
+    set_property(TARGET "${target}" APPEND PROPERTY ADDITIONAL_CLEAN_FILES
+      "${module_directory}/${SwiftCore_VARIANT_MODULE_TRIPLE}.swiftmodule"
+      "${module_directory}/${SwiftCore_VARIANT_MODULE_TRIPLE}.swiftdoc"
+      "${module_directory}/${SwiftCore_VARIANT_MODULE_TRIPLE}.swiftsourceinfo")
   endif()
+  add_custom_command(OUTPUT "${module_directory}/${SwiftCore_MODULE_TRIPLE}.swiftmodule"
+    DEPENDS ${target})
+  target_sources(${target}
+    INTERFACE
+      $<BUILD_INTERFACE:${module_directory}/${SwiftCore_MODULE_TRIPLE}.swiftmodule>)
 
   # Generate textual swift interfaces is library-evolution is enabled
   if(SwiftCore_ENABLE_LIBRARY_EVOLUTION)
     target_compile_options(${target} PRIVATE
-      $<$<COMPILE_LANGUAGE:Swift>:-emit-module-interface-path$<SEMICOLON>${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftinterface>
-      $<$<COMPILE_LANGUAGE:Swift>:-emit-private-module-interface-path$<SEMICOLON>${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.private.swiftinterface>
-      $<$<COMPILE_LANGUAGE:Swift>:-library-level$<SEMICOLON>api>
-      $<$<COMPILE_LANGUAGE:Swift>:-Xfrontend$<SEMICOLON>-require-explicit-availability=ignore>)
-
-      # Emit catalyst swiftmodules and interfaces
-      if(SwiftCore_VARIANT_MODULE_TRIPLE)
-        target_compile_options(${target} PRIVATE
-          "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-interface-path ${variant_module_tmp_dir}/${target}.swiftinterface>"
-          "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-private-module-interface-path ${variant_module_tmp_dir}/${target}.private.swiftinterface>")
-      endif()
-  endif()
-endfunction()
-
-# Install the generated swift interface file for the target if library evolution
-# is enabled.
-function(install_swift_interface target)
-  # Install binary swift modules
-  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule"
-    RENAME "${SwiftCore_MODULE_TRIPLE}.swiftmodule"
-    DESTINATION "${SwiftCore_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule"
-    COMPONENT SwiftCore_development)
-  if(SwiftCore_VARIANT_MODULE_TRIPLE)
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${target}-${SwiftCore_VARIANT_MODULE_TRIPLE}/${target}.swiftmodule"
-      RENAME "${SwiftCore_VARIANT_MODULE_TRIPLE}.swiftmodule"
-      DESTINATION "${SwiftCore_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule"
-      COMPONENT SwiftCore_development)
-  endif()
-
-  # Install Swift interfaces if library-evolution is enabled
-  if(SwiftCore_ENABLE_LIBRARY_EVOLUTION)
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftinterface"
-      RENAME "${SwiftCore_MODULE_TRIPLE}.swiftinterface"
-      DESTINATION "${SwiftCore_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule"
-      COMPONENT SwiftCore_development)
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.private.swiftinterface"
-      RENAME "${SwiftCore_MODULE_TRIPLE}.private.swiftinterface"
-      DESTINATION "${SwiftCore_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule"
-      COMPONENT SwiftCore_development)
-
-    # Install catalyst interface files
+      $<$<COMPILE_LANGUAGE:Swift>:-emit-module-interface-path$<SEMICOLON>${module_directory}/${SwiftCore_MODULE_TRIPLE}.swiftinterface>
+      $<$<COMPILE_LANGUAGE:Swift>:-emit-private-module-interface-path$<SEMICOLON>${module_directory}/${SwiftCore_MODULE_TRIPLE}.private.swiftinterface>)
+    set_property(TARGET "${target}" APPEND PROPERTY ADDITIONAL_CLEAN_FILES
+      "${module_directory}/${SwiftCore_MODULE_TRIPLE}.swiftinterface"
+      "${module_directory}/${SwiftCore_MODULE_TRIPLE}.private.swiftinterface")
     if(SwiftCore_VARIANT_MODULE_TRIPLE)
-      install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${target}-${SwiftCore_VARIANT_MODULE_TRIPLE}/${target}.swiftinterface"
-        RENAME "${SwiftCore_VARIANT_MODULE_TRIPLE}.swiftinterface"
-        DESTINATION "${SwiftCore_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule"
-        COMPONENT SwiftCore_development)
-      install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${target}-${SwiftCore_VARIANT_MODULE_TRIPLE}/${target}.private.swiftinterface"
-        RENAME "${SwiftCore_VARIANT_MODULE_TRIPLE}.private.swiftinterface"
-        DESTINATION "${SwiftCore_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule"
-        COMPONENT SwiftCore_development)
+      target_compile_options(${target} PRIVATE
+        "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-interface-path ${module_directory}/${SwiftCore_VARIANT_MODULE_TRIPLE}.swiftinterface>"
+        "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-private-module-interface-path ${module_directory}/${SwiftCore_VARIANT_MODULE_TRIPLE}.private.swiftinterface>")
+      set_property(TARGET "${target}" APPEND PROPERTY ADDITIONAL_CLEAN_FILES
+        "${module_directory}/${SwiftCore_VARIANT_MODULE_TRIPLE}.swiftinterface"
+        "${module_directory}/${SwiftCore_VARIANT_MODULE_TRIPLE}.private.swiftinterface")
     endif()
+    target_compile_options(${target} PRIVATE
+      $<$<COMPILE_LANGUAGE:Swift>:-library-level$<SEMICOLON>api>
+      $<$<COMPILE_LANGUAGE:Swift>:-Xfrontend$<SEMICOLON>-require-explicit-availability=ignore>)
   endif()
 endfunction()
diff --git a/Runtimes/Core/cmake/modules/ExperimentalFeatures.cmake b/Runtimes/Core/cmake/modules/ExperimentalFeatures.cmake
index bc6b0bfd69ad1..d11fb6e8fcab3 100644
--- a/Runtimes/Core/cmake/modules/ExperimentalFeatures.cmake
+++ b/Runtimes/Core/cmake/modules/ExperimentalFeatures.cmake
@@ -4,10 +4,13 @@ add_compile_options(
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SE427NoInferenceOnExtension>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NonescapableTypes>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature InoutLifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependenceMutableAccessors>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature MemberImportVisibility>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature TypedThrows>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Macros>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature FreestandingMacros>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature BitwiseCopyable>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Extern>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature AllowUnsafeAttribute>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature ValueGenerics>")
diff --git a/Runtimes/Core/cmake/modules/InstallSwiftInterface.cmake b/Runtimes/Core/cmake/modules/InstallSwiftInterface.cmake
new file mode 100644
index 0000000000000..e246eba7d6a2c
--- /dev/null
+++ b/Runtimes/Core/cmake/modules/InstallSwiftInterface.cmake
@@ -0,0 +1,13 @@
+
+# Install the generated swift interface files for the target.
+function(install_swift_interface target)
+  # Swiftmodules are already in the directory structure
+  get_target_property(module_name ${target} Swift_MODULE_NAME)
+  if(NOT module_name)
+    set(module_name ${target})
+  endif()
+
+  install(DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule"
+    DESTINATION "${SwiftCore_INSTALL_SWIFTMODULEDIR}"
+    COMPONENT SwiftCore_development)
+endfunction()
diff --git a/Runtimes/Core/cmake/modules/PlatformInfo.cmake b/Runtimes/Core/cmake/modules/PlatformInfo.cmake
index 999d6b0595f1b..49ccc06aa4759 100644
--- a/Runtimes/Core/cmake/modules/PlatformInfo.cmake
+++ b/Runtimes/Core/cmake/modules/PlatformInfo.cmake
@@ -1,3 +1,9 @@
+include("${PROJECT_BINARY_DIR}/build/DetectedPlatformInfo.cmake" OPTIONAL)
+
+if(SwiftCore_PLATFORM_INFO_SET)
+  return()
+endif()
+
 if(NOT SwiftCore_SIZEOF_POINTER)
   set(SwiftCore_SIZEOF_POINTER "${CMAKE_SIZEOF_VOID_P}" CACHE STRING "Size of a pointer in bytes")
   message(CONFIGURE_LOG "Stdlib Pointer size: ${CMAKE_SIZEOF_VOID_P}")
@@ -36,3 +42,51 @@ if(NOT SwiftCore_ARCH_SUBDIR)
 
   message(CONFIGURE_LOG "Swift Arch: ${arch}")
 endif()
+
+# Note: *moduleTriple* doesn't have an "x" on the end of "macos"; just to be
+# safe, we support both cases here.
+set(availability_platform_macos "macOS")
+set(availaiblity_platform_macosx "macOS")
+set(availability_platform_ios "iOS")
+set(availability_platform_watchos "watchOS")
+set(availability_platform_tvos "tvOS")
+set(availability_platform_xros "visionOS")
+set(availability_platform_bridgeos "bridgeOS")
+
+if(NOT SwiftCore_SWIFT_AVAILABILITY_PLATFORM)
+  if(SwiftCore_MODULE_TRIPLE MATCHES ".*-([^-]+)-simulator$")
+    set(platform "${CMAKE_MATCH_1}")
+  elseif(SwiftCore_MODULE_TRIPLE MATCHES ".*-([^-]+)-msvc$")
+    set(platform "${CMAKE_MATCH_1}")
+  elseif(SwiftCore_MODULE_TRIPLE MATCHES ".*-([^-]+)$")
+    set(platform "${CMAKE_MATCH_1}")
+  else()
+    message(WARNING "Unable to extract platform name from triple ${SwiftCore_MODULE_TRIPLE}")
+  endif()
+
+  if(availability_platform_${platform})
+    set(SwiftCore_SWIFT_AVAILABILITY_PLATFORM "${availability_platform_${platform}}")
+  else()
+    set(SwiftCore_SWIFT_AVAILABILITY_PLATFORM "unknown")
+    message(WARNING "Unknown platform ${platform} for availability")
+  endif()
+endif()
+
+set(SwiftCore_VARIANT_AVAILABILITY_PLATFORM "none")
+if(SwiftCore_VARIANT_MODULE_TRIPLE)
+  if(SwiftCore_VARIANT_MODULE_TRIPLE MATCHES ".*-([^-]+)$")
+    set(platform "${CMAKE_MATCH_1}")
+  else()
+    message(FATAL_ERROR "Unable to extract platform name from triple ${SwiftCore_VARIANT_MODULE_TRIPLE}")
+  endif()
+
+  if(availability_platform_${platform})
+    set(SwiftCore_VARIANT_AVAILABILITY_PLATFORM "${availability_platform_${platform}}")
+  else()
+    message(WARNING "Unknown platform ${platform} for variant availability")
+  endif()
+endif()
+
+configure_file("${CMAKE_CURRENT_LIST_DIR}/DetectedPlatformInfo.cmake.in"
+  "${PROJECT_BINARY_DIR}/build/DetectedPlatformInfo.cmake"
+  @ONLY)
diff --git a/Runtimes/Core/core/CMakeLists.txt b/Runtimes/Core/core/CMakeLists.txt
index 20df62386e987..8dcd95ec870bc 100644
--- a/Runtimes/Core/core/CMakeLists.txt
+++ b/Runtimes/Core/core/CMakeLists.txt
@@ -154,6 +154,8 @@ add_library(swiftCore
   Span/RawSpan.swift
   Span/MutableSpan.swift
   Span/MutableRawSpan.swift
+  Span/OutputSpan.swift
+  Span/OutputRawSpan.swift
   StaticString.swift
   StaticPrint.swift
   Stride.swift
@@ -188,7 +190,6 @@ add_library(swiftCore
   StringWordBreaking.swift
   Substring.swift
   SwiftNativeNSArray.swift
-  SwiftSettings.swift
   TemporaryAllocation.swift
   ThreadLocalStorage.swift
   UIntBuffer.swift
@@ -208,6 +209,13 @@ add_library(swiftCore
   UnsafeRawPointer.swift
   UTFEncoding.swift
   UTF8.swift
+  UTF8EncodingError.swift
+  UTF8Span.swift
+  UTF8SpanBits.swift
+  UTF8SpanComparisons.swift
+  UTF8SpanFundamentals.swift
+  UTF8SpanInternalHelpers.swift
+  UTF8SpanIterators.swift
   UTF16.swift
   UTF32.swift
   Unicode.swift # ORDER DEPENDENCY: must follow new unicode support
@@ -253,13 +261,19 @@ if(NOT LINUX AND NOT ANDROID)
 endif()
 
 if(SwiftCore_ENABLE_COMMANDLINE_SUPPORT)
-  target_sources(swiftCore PRIVATE CommandLine.swift)
-  target_link_libraries(swiftCore PRIVATE swiftCommandLineSupport)
+  target_sources(swiftCore PRIVATE
+    CommandLine.swift)
 endif()
 
 if(SwiftCore_ENABLE_VECTOR_TYPES)
-  gyb_expand(SIMDConcreteOperations.swift.gyb
-    SIMDConcreteOperations.swift
+  gyb_expand(SIMDFloatConcreteOperations.swift.gyb
+    SIMDFloatConcreteOperations.swift
+    FLAGS "-DCMAKE_SIZEOF_VOID_P=${SwiftCore_SIZEOF_POINTER}")
+  gyb_expand(SIMDIntegerConcreteOperations.swift.gyb
+    SIMDIntegerConcreteOperations.swift
+    FLAGS "-DCMAKE_SIZEOF_VOID_P=${SwiftCore_SIZEOF_POINTER}")
+  gyb_expand(SIMDMaskConcreteOperations.swift.gyb
+    SIMDMaskConcreteOperations.swift
     FLAGS "-DCMAKE_SIZEOF_VOID_P=${SwiftCore_SIZEOF_POINTER}")
   gyb_expand(SIMDVectorTypes.swift.gyb
     SIMDVectorTypes.swift
@@ -267,13 +281,19 @@ if(SwiftCore_ENABLE_VECTOR_TYPES)
 
   target_sources(swiftCore PRIVATE
     SIMDVector.swift
-    "${CMAKE_CURRENT_BINARY_DIR}/SIMDConcreteOperations.swift"
+    "${CMAKE_CURRENT_BINARY_DIR}/SIMDFloatConcreteOperations.swift"
+    "${CMAKE_CURRENT_BINARY_DIR}/SIMDIntegerConcreteOperations.swift"
+    "${CMAKE_CURRENT_BINARY_DIR}/SIMDMaskConcreteOperations.swift"
     "${CMAKE_CURRENT_BINARY_DIR}/SIMDVectorTypes.swift")
 endif()
 
 set_target_properties(swiftCore PROPERTIES
   Swift_MODULE_NAME Swift
   LINKER_LANGUAGE CXX)
+if(NOT BUILD_SHARED_LIBS AND CMAKE_STATIC_LIBRARY_PREFIX_Swift)
+  set_target_properties(swiftCore PROPERTIES
+    PREFIX ${CMAKE_STATIC_LIBRARY_PREFIX_Swift})
+endif()
 
 target_compile_definitions(swiftCore
   PRIVATE
@@ -294,7 +314,8 @@ target_compile_options(swiftCore PRIVATE
   $<$<COMPILE_LANGUAGE:Swift>:-nostdimport>
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -group-info-path -Xfrontend ${CMAKE_CURRENT_SOURCE_DIR}/GroupInfo.json>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-objc-attr-requires-foundation-module>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -require-explicit-availability=ignore>")
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -require-explicit-availability=ignore>"
+  "$<$<AND:$<PLATFORM_ID:Darwin>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -previous-module-installname-map-file -Xfrontend ${CMAKE_CURRENT_SOURCE_DIR}/PreviousModuleInstallName.json>")
 if(NOT "${CMAKE_BUILD_TYPE}" STREQUAL "MinSizeRel")
   # Using these in MinSizeRel would result in a 15% increase in the binary size
   target_compile_options(swiftCore PRIVATE
@@ -315,7 +336,9 @@ target_link_libraries(swiftCore
     swiftThreading
     $<$<NOT:$<PLATFORM_ID:Darwin>>:swiftrt$<$<PLATFORM_ID:Windows>:T>>
   PUBLIC
-    swiftShims)
+    swiftShims
+  INTERFACE
+    swiftRuntimeCMakeConfig)
 
 string(TOLOWER "${SwiftCore_OBJECT_FORMAT}" SwiftCore_OBJECT_FORMAT_lc)
 if("${SwiftCore_OBJECT_FORMAT_lc}" STREQUAL "elf")
@@ -362,7 +385,7 @@ emit_swift_interface(swiftCore)
 install_swift_interface(swiftCore)
 
 # Configure plist creation for Darwin platforms.
-generate_plist("${CMAKE_PROJECT_NAME}" "${CMAKE_PROJECT_VERSION}" swiftCore)
+generate_plist(swiftCore "${CMAKE_PROJECT_VERSION}" swiftCore)
 embed_manifest(swiftCore)
 
 include("${SwiftCore_VENDOR_MODULE_DIR}/swiftCore.cmake" OPTIONAL)
diff --git a/Runtimes/Core/runtime/CMakeConfig.h.in b/Runtimes/Core/runtime/CMakeConfig.h.in
index 1aa1576a3bc4a..80d2e8b7d72ff 100644
--- a/Runtimes/Core/runtime/CMakeConfig.h.in
+++ b/Runtimes/Core/runtime/CMakeConfig.h.in
@@ -4,9 +4,6 @@
 #ifndef SWIFT_RUNTIME_CMAKECONFIG_H
 #define SWIFT_RUNTIME_CMAKECONFIG_H
 
-#cmakedefine01 SWIFT_BNI_OS_BUILD
-#cmakedefine01 SWIFT_BNI_XCODE_BUILD
-
 #define SWIFT_VERSION_MAJOR "@SwiftCore_VERSION_MAJOR@"
 #define SWIFT_VERSION_MINOR "@SwiftCore_VERSION_MINOR@"
 
diff --git a/Runtimes/Core/runtime/CMakeLists.txt b/Runtimes/Core/runtime/CMakeLists.txt
index bed1399425a1e..d226c7380fe71 100644
--- a/Runtimes/Core/runtime/CMakeLists.txt
+++ b/Runtimes/Core/runtime/CMakeLists.txt
@@ -1,19 +1,11 @@
-# TODO: clean this up so it's less Apple-specific.
-# Detect B&I builds.
-set(SWIFT_BNI_OS_BUILD FALSE)
-set(SWIFT_BNI_XCODE_BUILD FALSE)
-if(DEFINED ENV{RC_XBS})
-  if((NOT DEFINED ENV{RC_XCODE} OR NOT "$ENV{RC_XCODE}") AND (NOT DEFINED ENV{RC_PLAYGROUNDS} OR NOT "$ENV{RC_PLAYGROUNDS}"))
-    set(SWIFT_BNI_OS_BUILD TRUE)
-  else()
-    set(SWIFT_BNI_XCODE_BUILD TRUE)
-  endif()
-endif()
-
 configure_file("CMakeConfig.h.in"
   "${PROJECT_BINARY_DIR}/include/swift/Runtime/CMakeConfig.h"
   ESCAPE_QUOTES @ONLY)
 
+add_library(swiftRuntimeCMakeConfig INTERFACE)
+target_include_directories(swiftRuntimeCMakeConfig INTERFACE
+  $<$<COMPILE_LANGUAGE:C,CXX,Swift>:$<INSTALL_INTERFACE:$<INSTALL_PREFIX>/${CMAKE_INSTALL_INCLUDEDIR}>>)
+
 add_library(swiftRuntime OBJECT
     "${PROJECT_SOURCE_DIR}/CompatibilityOverride/CompatibilityOverride.cpp"
     AnyHashableSupport.cpp
@@ -144,6 +136,14 @@ if(SwiftCore_ENABLE_OBJC_INTEROP)
     ObjCRuntimeGetImageNameFromClass.mm)
 endif()
 
+install(FILES
+  "${PROJECT_BINARY_DIR}/include/swift/Runtime/CMakeConfig.h"
+  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/swift/Runtime"
+  COMPONENT SwiftCore_development)
+install(TARGETS swiftRuntimeCMakeConfig
+  EXPORT SwiftCoreTargets
+  COMPONENT SwiftCore_development)
+
 if(NOT BUILD_SHARED_LIBS)
   install(TARGETS swiftRuntime
     EXPORT SwiftCoreTargets
diff --git a/Runtimes/Overlay/Android/Android/CMakeLists.txt b/Runtimes/Overlay/Android/Android/CMakeLists.txt
new file mode 100644
index 0000000000000..2b6ffee693c3e
--- /dev/null
+++ b/Runtimes/Overlay/Android/Android/CMakeLists.txt
@@ -0,0 +1,31 @@
+
+gyb_expand(tgmath.swift.gyb tgmath.swift)
+
+add_library(swiftAndroid
+  tgmath.swift
+  Android.swift
+  Platform.swift
+  POSIXError.swift
+  TiocConstants.swift)
+set_target_properties(swiftAndroid PROPERTIES
+  Swift_MODULE_NAME Android)
+target_compile_definitions(swiftAndroid PRIVATE
+  $<$<BOOL:${SwiftOverlay_ENABLE_REFLECTION}>:SWIFT_ENABLE_REFLECTION>)
+target_link_libraries(swiftAndroid PUBLIC
+  SwiftAndroid)
+target_link_libraries(swiftAndroid PRIVATE
+  swiftCore)
+
+# FIXME: Why is this not implicitly in the interface flags?
+target_include_directories(swiftAndroid INTERFACE
+  "$<$<COMPILE_LANGUAGE:Swift>:$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>$<INSTALL_INTERFACE:$<INSTALL_PREFIX>/${SwiftCore_INSTALL_SWIFTMODULEDIR}>>")
+
+install(TARGETS swiftAndroid
+  EXPORT SwiftOverlayTargets
+  ARCHIVE DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swiftAndroid)
+install_swift_interface(swiftAndroid)
+
+embed_manifest(swiftAndroid)
diff --git a/Runtimes/Overlay/Android/CMakeLists.txt b/Runtimes/Overlay/Android/CMakeLists.txt
new file mode 100644
index 0000000000000..8642382b6efe5
--- /dev/null
+++ b/Runtimes/Overlay/Android/CMakeLists.txt
@@ -0,0 +1,4 @@
+
+add_subdirectory(clang)
+add_subdirectory(Android)
+add_subdirectory(Math)
diff --git a/Runtimes/Overlay/Android/Math/CMakeLists.txt b/Runtimes/Overlay/Android/Math/CMakeLists.txt
new file mode 100644
index 0000000000000..5e1d53a3ddff0
--- /dev/null
+++ b/Runtimes/Overlay/Android/Math/CMakeLists.txt
@@ -0,0 +1,18 @@
+
+add_library(swift_math
+  Math.swift)
+set_target_properties(swift_math PROPERTIES
+  Swift_MODULE_NAME math)
+target_link_libraries(swift_math PRIVATE
+  SwiftAndroid
+  swiftCore)
+
+install(TARGETS swift_math
+  EXPORT SwiftOverlayTargets
+  ARCHIVE DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swift_math)
+install_swift_interface(swift_math)
+
+embed_manifest(swift_math)
diff --git a/Runtimes/Overlay/Android/clang/CMakeLists.txt b/Runtimes/Overlay/Android/clang/CMakeLists.txt
new file mode 100644
index 0000000000000..2ca7b561b1f0c
--- /dev/null
+++ b/Runtimes/Overlay/Android/clang/CMakeLists.txt
@@ -0,0 +1,41 @@
+
+# FIXME: how do we determine the sysroot? `CMAKE_SYSROOT` does not contain the sysroot.
+file(CONFIGURE
+  OUTPUT android-ndk-overlay.yaml
+  CONTENT [[
+---
+version: 0
+case-sensitive: false
+use-external-names: false
+roots:
+  - name: "@CMAKE_ANDROID_NDK@/toolchains/llvm/prebuilt/windows-x86_64/sysroot/usr/include"
+    type: directory
+    contents:
+      - name: module.modulemap
+        type: file
+        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/android.modulemap"
+      - name: SwiftAndroidNDK.h
+        type: file
+        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/SwiftAndroidNDK.h"
+      - name: SwiftBionic.h
+        type: file
+        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/SwiftBionic.h"
+]]
+ESCAPE_QUOTES @ONLY NEWLINE_STYLE LF)
+
+add_library(SwiftAndroid INTERFACE)
+target_compile_options(SwiftAndroid INTERFACE
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xcc --sysroot=\"${CMAKE_ANDROID_NDK_TOOLCHAIN_UNIFIED}/sysroot\">"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-vfsoverlay ${CMAKE_CURRENT_BINARY_DIR}/android-ndk-overlay.yaml>")
+
+install(TARGETS SwiftAndroid
+  EXPORT SwiftOverlayTargets)
+install(FILES
+  android.modulemap
+  SwiftAndroidNDK.h
+  SwiftBionic.h
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/swift/${SwiftOverlay_PLATFORM_SUBDIR}/${SwiftOverlay_ARCH_SUBDIR})
+install(FILES
+  posix_filesystem.apinotes
+  spawn.apinotes
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/swift/apinotes)
diff --git a/Runtimes/Overlay/CMakeLists.txt b/Runtimes/Overlay/CMakeLists.txt
index 030a1c326587d..61afeb8f6459d 100644
--- a/Runtimes/Overlay/CMakeLists.txt
+++ b/Runtimes/Overlay/CMakeLists.txt
@@ -1,26 +1,29 @@
 
 cmake_minimum_required(VERSION 3.26...3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
 
 set(CMAKE_C_VISIBILITY_PRESET "hidden")
 set(CMAKE_CXX_VISIBILITY_PRESET "hidden")
 set(CMAKE_VISIBILITY_INLINES_HIDDEN YES)
 
-list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake/modules")
-
-# NOTE: always use the 3-component style as the expansion as
-# `${PROJECT_VERSION}` will not extend this to the complete form and this can
-# change the behaviour for comparison with non-SemVer compliant parsing. If
-# possible, use the 4-version component as that is used to differentiate the
-# builds of the runtime for Windows.
-if($ENV{BUILD_NUMBER})
-  # NOTE: SxS modules have a limit on each component being [0-65535].
-  # https://learn.microsoft.com/en-us/windows/win32/sbscs/assembly-versions
-  math(EXPR BUILD_NUMBER "$ENV{BUILD_NUMBER} % 65535")
-  set(BUILD_NUMBER ".${BUILD_NUMBER}")
+list(APPEND CMAKE_MODULE_PATH
+  "${CMAKE_SOURCE_DIR}/cmake/modules"
+  "${CMAKE_SOURCE_DIR}/../cmake/modules")
+
+if(POLICY CMP0157 AND CMAKE_Swift_COMPILER_USE_OLD_DRIVER)
+  cmake_policy(SET CMP0157 OLD)
 endif()
+
+include(SwiftProjectVersion)
 project(SwiftOverlay
   LANGUAGES C CXX Swift
-  VERSION 6.1.0${BUILD_NUMBER})
+  VERSION ${SWIFT_RUNTIME_VERSION})
+
+set(CMAKE_Swift_LANGUAGE_VERSION 5)
 
 find_package(SwiftCore)
 
@@ -30,26 +33,92 @@ set(SwiftOverlay_SWIFTC_SOURCE_DIR
   "${PROJECT_SOURCE_DIR}/../../"
   CACHE FILEPATH "Path to the root source directory of the Swift compiler")
 
+set(${PROJECT_NAME}_VENDOR_MODULE_DIR "${CMAKE_SOURCE_DIR}/cmake/modules/vendor"
+  CACHE FILEPATH "Location for private build system extension")
+
 include(GNUInstallDirs)
 
 include(gyb)
 include(AvailabilityMacros)
 include(DefaultSettings)
 include(EmitSwiftInterface)
+include(InstallSwiftInterface)
 include(PlatformInfo)
 include(ResourceEmbedding)
 
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/Settings.cmake" OPTIONAL)
+
 defaulted_option(SwiftOverlay_ENABLE_REFLECTION "Enable runtime support for mirrors and reflection support")
+defaulted_option(SwiftOverlay_ENABLE_CXX_INTEROP "Enable C++ Interop support overlays")
 
 option(SwiftOverlay_INSTALL_NESTED_SUBDIR "Install libraries under a platform and architecture subdirectory" ON)
 set(SwiftOverlay_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${SwiftOverlay_INSTALL_NESTED_SUBDIR}>:/${SwiftOverlay_PLATFORM_SUBDIR}/${SwiftOverlay_ARCH_SUBDIR}>")
 set(SwiftOverlay_INSTALL_SWIFTMODULEDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${SwiftOverlay_INSTALL_NESTED_SUBDIR}>:/${SwiftOverlay_PLATFORM_SUBDIR}>")
 
+option(SwiftOverlay_ENABLE_LIBRARY_EVOLUTION "Generate ABI resilient runtime libraries"
+  ${SwiftCore_ENABLE_LIBRARY_EVOLUTION})
+option(SwiftOverlay_ENABLE_BACKDEPLOYMENT_SUPPORT "Add symbols for runtime backdeployment"
+  ${SwiftCore_ENABLE_BACKDEPLOYMENT_SUPPORT})
+
+add_compile_definitions(
+  $<$<BOOL:${SwiftOverlay_ENABLE_BACKDEPLOYMENT_SUPPORT}>:SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT>)
+
 add_compile_options(
+  $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>
+  $<$<COMPILE_LANGUAGE:Swift>:-nostdlibimport>
+  $<$<COMPILE_LANGUAGE:Swift>:-strict-memory-safety>
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-lexical-lifetimes=false>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-concurrency-module-import>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>")
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enforce-exclusivity=unchecked>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
+
+include(ExperimentalFeatures)
+
+# LNK4049: symbol 'symbol' defined in 'filename.obj' is imported
+# LNK4286: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj'
+# LNK4217: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj' in function 'function'
+#
+# We cannot selectively filter the linker warnings as we do not use the MSVC
+# frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
+# a compromise, treat all linker warnings as errors.
+add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Android,Linux>:LINKER:-z,defs>)
+
+include(ExperimentalFeatures)
 
 add_subdirectory(clang)
+if(ANDROID)
+  add_subdirectory(Android)
+endif()
 if(WIN32)
   add_subdirectory(Windows)
 endif()
+
+if(SwiftOverlay_ENABLE_CXX_INTEROP)
+  add_subdirectory(Cxx)
+endif()
+
+# Inter-project install info
+export(EXPORT SwiftOverlayTargets
+  FILE "cmake/SwiftOverlay/SwiftOverlayTargets.cmake")
+install(EXPORT SwiftOverlayTargets
+  DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/SwiftOverlay"
+  FILE "SwiftOverlayTargets.cmake"
+  COMPONENT SwiftOverlayCMake)
+include(CMakePackageConfigHelpers)
+configure_package_config_file("${CMAKE_CURRENT_SOURCE_DIR}/cmake/interface/SwiftOverlayConfig.cmake.in"
+  "${CMAKE_CURRENT_BINARY_DIR}/cmake/SwiftOverlay/SwiftOverlayConfig.cmake"
+  INSTALL_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/SwiftOverlay")
+write_basic_package_version_file("${CMAKE_CURRENT_BINARY_DIR}/cmake/SwiftOverlay/SwiftOverlayConfigVersion.cmake"
+  VERSION "${PROJECT_VERSION}"
+  COMPATIBILITY ExactVersion)
+install(FILES
+  "${CMAKE_CURRENT_BINARY_DIR}/cmake/SwiftOverlay/SwiftOverlayConfig.cmake"
+  "${CMAKE_CURRENT_BINARY_DIR}/cmake/SwiftOverlay/SwiftOverlayConfigVersion.cmake"
+  DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/SwiftOverlay")
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/swiftOverlay.cmake" OPTIONAL)
diff --git a/Runtimes/Overlay/Cxx/CMakeLists.txt b/Runtimes/Overlay/Cxx/CMakeLists.txt
new file mode 100644
index 0000000000000..5f43f25409f7c
--- /dev/null
+++ b/Runtimes/Overlay/Cxx/CMakeLists.txt
@@ -0,0 +1,49 @@
+
+include(CheckSymbolExists)
+check_symbol_exists(_LIBCPP_VERSION "version" HAVE_LIBCPP_VERSION)
+check_symbol_exists(__GLIBCXX__ "version" HAVE___GLIBCXX__)
+
+if(NOT APPLE)
+  add_subdirectory(cxxshim)
+endif()
+if(HAVE___GLIBCXX__)
+  add_subdirectory(libstdcxx)
+endif()
+add_subdirectory(std)
+
+add_library(swiftCxx STATIC
+  CxxConvertibleToBool.swift
+  CxxConvertibleToCollection.swift
+  CxxDictionary.swift
+  CxxOptional.swift
+  CxxPair.swift
+  CxxRandomAccessCollection.swift
+  CxxSequence.swift
+  CxxSet.swift
+  CxxSpan.swift
+  CxxVector.swift
+  UnsafeCxxIterators.swift)
+set_target_properties(swiftCxx PROPERTIES
+  Swift_MODULE_NAME Cxx)
+target_compile_options(swiftCxx PRIVATE
+  "$<$<COMPILE_LANGUAGE:Swift>:-cxx-interoperability-mode=default>"
+  "$<$<COMPILE_LANGUAGE:Swift>:-warn-implicit-overrides>"
+  # This module should not pull in the C++ standard library, so we disable it
+  # explicitly.  For functionality that depends on the C++ stdlib, use C++
+  # stdlib overlay (`swiftstd` module).
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xcc -nostdinc++>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature AllowUnsafeAttribute>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature BuiltinModule>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Lifetimes>")
+target_link_libraries(swiftCxx PRIVATE
+  swiftCore)
+
+install(TARGETS swiftCxx
+  EXPORT SwiftOverlayTargets
+  ARCHIVE DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swiftCxx)
+install_swift_interface(swiftCxx)
+
+embed_manifest(swiftCxx)
diff --git a/Runtimes/Overlay/Cxx/cxxshim/CMakeLists.txt b/Runtimes/Overlay/Cxx/cxxshim/CMakeLists.txt
new file mode 100644
index 0000000000000..de0e8b1fa5b7c
--- /dev/null
+++ b/Runtimes/Overlay/Cxx/cxxshim/CMakeLists.txt
@@ -0,0 +1,17 @@
+
+add_library(cxxshim INTERFACE)
+target_compile_options(cxxshim INTERFACE
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xcc -fmodule-map-file=${CMAKE_CURRENT_SOURCE_DIR}/libcxxshim.modulemap>")
+target_include_directories(cxxshim INTERFACE
+  $<$<COMPILE_LANGUAGE:Swift>:$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>>)
+
+install(TARGETS cxxshim
+  EXPORT SwiftOverlayTargets
+  ARCHIVE DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+install(FILES
+  libcxxshim.h
+  libcxxshim.modulemap
+  libcxxstdlibshim.h
+  DESTINATION "${CMAKE_INSTALL_LIBDIR}/swift/${SwiftOverlay_PLATFORM_SUBDIR}")
diff --git a/Runtimes/Overlay/Cxx/libstdcxx/CMakeLists.txt b/Runtimes/Overlay/Cxx/libstdcxx/CMakeLists.txt
new file mode 100644
index 0000000000000..4050cd5be0efc
--- /dev/null
+++ b/Runtimes/Overlay/Cxx/libstdcxx/CMakeLists.txt
@@ -0,0 +1,16 @@
+
+add_library(libstdcxx INTERFACE)
+target_compile_options(libstdcxx INTERFACE
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xcc -fmodule-map-file=${CMAKE_CURRENT_SOURCE_DIR}/libstdcxx.modulemap>")
+target_include_directories(libstdcxx INTERFACE
+  $<$<COMPILE_LANGUAGE:Swift>:$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>>)
+
+install(TARGETS libstdcxx
+  EXPORT SwiftOverlayTargets
+  ARCHIVE DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+install(FILES
+  libstdcxx.h
+  libstdcxx.modulemap
+  DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}")
diff --git a/Runtimes/Overlay/Cxx/std/CMakeLists.txt b/Runtimes/Overlay/Cxx/std/CMakeLists.txt
new file mode 100644
index 0000000000000..7463b92290c8e
--- /dev/null
+++ b/Runtimes/Overlay/Cxx/std/CMakeLists.txt
@@ -0,0 +1,44 @@
+
+add_library(swiftCxxStdlib STATIC
+  std.swift
+  Chrono.swift
+  String.swift)
+set_target_properties(swiftCxxStdlib PROPERTIES
+  Swift_MODULE_NAME CxxStdlib)
+target_compile_options(swiftCxxStdlib PRIVATE
+  "-strict-memory-safety"
+  "-cxx-interoperability-mode=default"
+  "SHELL:-enable-experimental-feature AllowUnsafeAttribute"
+  "SHELL:-enable-experimental-feature Lifetimes"
+  # This flag is unnecessary when building with newer compilers that allow using
+  # C++ symbols in resilient overlays (see f4204568).
+  "SHELL:-enable-experimental-feature AssumeResilientCxxTypes"
+  # The varying modularization of the C++ standard library on different
+  # platforms makes it difficult to enable MemberImportVisibility for this
+  # module
+  "SHELL:-disable-upcoming-feature MemberImportVisibility"
+  "SHELL:-Xfrontend -module-interface-preserve-types-as-written")
+# NOTE: We need to setup the sysroot here as we need to ensure that we pick up
+# the module.map from the C++ runtime for the `std` (spelt `CxxStdlib`) import.
+target_compile_options(swiftCxxStdlib PRIVATE
+  "$<$<PLATFORM_ID:Android>:SHELL:-Xcc --sysroot -Xcc ${CMAKE_ANDROID_NDK_TOOLCHAIN_UNIFIED}/sysroot>")
+target_link_libraries(swiftCxxStdlib PRIVATE
+  $<$<BOOL:${HAVE___GLIBCXX__}>:libstdcxx>
+  $<$<NOT:$<PLATFORM_ID:Darwin>>:cxxshim>
+  swiftCxx
+  swiftCore
+  swift_Builtin_float
+  $<$<PLATFORM_ID:Android>:SwiftAndroid>
+  $<$<PLATFORM_ID:Windows>:ClangModules>)
+
+install(FILES std.apinotes
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/swift/apinotes)
+install(TARGETS swiftCxxStdlib
+  EXPORT SwiftOverlayTargets
+  ARCHIVE DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swiftCxxStdlib)
+install_swift_interface(swiftCxxStdlib)
+
+embed_manifest(swiftCxxStdlib)
diff --git a/Runtimes/Overlay/Windows/CRT/CMakeLists.txt b/Runtimes/Overlay/Windows/CRT/CMakeLists.txt
index 0c67c3f5fd683..d93e1efd30150 100644
--- a/Runtimes/Overlay/Windows/CRT/CMakeLists.txt
+++ b/Runtimes/Overlay/Windows/CRT/CMakeLists.txt
@@ -12,12 +12,19 @@ set_target_properties(swiftCRT PROPERTIES
 target_compile_definitions(swiftCRT PRIVATE
   $<$<BOOL:${SwiftOverlay_ENABLE_REFLECTION}>:SWIFT_ENABLE_REFLECTION>)
 target_compile_options(swiftCRT PRIVATE
+  "SHELL:-Xfrontend -disable-force-load-symbols"
   "SHELL:-Xcc -D_USE_MATH_DEFINES")
+target_link_libraries(swiftCRT PUBLIC
+  ClangModules)
 target_link_libraries(swiftCRT PRIVATE
-  ClangModules
   swiftCore)
 
+# FIXME: Why is this not implicitly in the interface flags?
+target_include_directories(swiftCRT INTERFACE
+  "$<$<COMPILE_LANGUAGE:Swift>:$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>$<INSTALL_INTERFACE:$<INSTALL_PREFIX>/${SwiftCore_INSTALL_SWIFTMODULEDIR}>>")
+
 install(TARGETS swiftCRT
+  EXPORT SwiftOverlayTargets
   ARCHIVE DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
   LIBRARY DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
   RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
diff --git a/Runtimes/Overlay/Windows/WinSDK/CMakeLists.txt b/Runtimes/Overlay/Windows/WinSDK/CMakeLists.txt
index 9140c71e0261f..954449a6a8b71 100644
--- a/Runtimes/Overlay/Windows/WinSDK/CMakeLists.txt
+++ b/Runtimes/Overlay/Windows/WinSDK/CMakeLists.txt
@@ -3,13 +3,21 @@ add_library(swiftWinSDK
   WinSDK.swift)
 set_target_properties(swiftWinSDK PROPERTIES
   Swift_MODULE_NAME WinSDK)
-target_compile_definitions(swiftCRT PRIVATE
+target_compile_definitions(swiftWinSDK PRIVATE
   $<$<BOOL:${SwiftOverlay_ENABLE_REFLECTION}>:SWIFT_ENABLE_REFLECTION>)
+target_compile_options(swiftWinSDK PRIVATE
+  "SHELL:-Xfrontend -disable-force-load-symbols")
+target_link_libraries(swiftWinSDK PUBLIC
+  ClangModules)
 target_link_libraries(swiftWinSDK PRIVATE
-  ClangModules
   swiftCore)
 
+# FIXME: Why is this not implicitly in the interface flags?
+target_include_directories(swiftWinSDK INTERFACE
+  "$<$<COMPILE_LANGUAGE:Swift>:$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>$<INSTALL_INTERFACE:$<INSTALL_PREFIX>/${SwiftCore_INSTALL_SWIFTMODULEDIR}>>")
+
 install(TARGETS swiftWinSDK
+  EXPORT SwiftOverlayTargets
   ARCHIVE DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
   LIBRARY DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
   RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
diff --git a/Runtimes/Overlay/Windows/clang/CMakeLists.txt b/Runtimes/Overlay/Windows/clang/CMakeLists.txt
index 8f2872d1c8ce1..1d88b8ed024ad 100644
--- a/Runtimes/Overlay/Windows/clang/CMakeLists.txt
+++ b/Runtimes/Overlay/Windows/clang/CMakeLists.txt
@@ -18,14 +18,20 @@ roots:
     contents:
       - name: module.modulemap
         type: file
-        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/winsdk.modulemap"
+        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/winsdk_um.modulemap"
+  - name: "@WindowsSdkDir@/Include/@WindowsSDKVersion@/shared"
+    type: directory
+    contents:
+      - name: module.modulemap
+        type: file
+        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/winsdk_shared.modulemap"
   - name: "@UniversalCRTSdkDir@/Include/@UCRTVersion@/ucrt"
     type: directory
     contents:
       - name: module.modulemap
         type: file
         external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/ucrt.modulemap"
-  - name: "@VCToolsInstallDir@include"
+  - name: "@VCToolsInstallDir@/include"
     type: directory
     contents:
       - name: module.modulemap
@@ -41,9 +47,12 @@ add_library(ClangModules INTERFACE)
 target_compile_options(ClangModules INTERFACE
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-vfsoverlay ${CMAKE_CURRENT_BINARY_DIR}/windows-sdk-overlay.yaml>")
 
+install(TARGETS ClangModules
+  EXPORT SwiftOverlayTargets)
 install(FILES
   ucrt.modulemap
   vcruntime.apinotes
   vcruntime.modulemap
-  winsdk.modulemap
+  winsdk_um.modulemap
+  winsdk_shared.modulemap
   DESTINATION ${CMAKE_INSTALL_DATAROOTDIR})
diff --git a/Runtimes/Overlay/clang/CMakeLists.txt b/Runtimes/Overlay/clang/CMakeLists.txt
index c1c91ad2ea126..3be1089f19847 100644
--- a/Runtimes/Overlay/clang/CMakeLists.txt
+++ b/Runtimes/Overlay/clang/CMakeLists.txt
@@ -1,3 +1,4 @@
+include(CatalystSupport)
 
 gyb_expand(float.swift.gyb float.swift)
 
@@ -7,12 +8,14 @@ add_library(swift_Builtin_float
 set_target_properties(swift_Builtin_float PROPERTIES
   Swift_MODULE_NAME _Builtin_float)
 target_compile_options(swift_Builtin_float PRIVATE
-  "$<$<PLATFORM_ID:Darwin>:SHELL:-Xfrontend -module-abi-name -Xfrontend Darwin>")
+  "$<$<AND:$<PLATFORM_ID:Darwin>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -module-abi-name -Xfrontend Darwin>"
+  $<$<COMPILE_LANGUAGE:Swift>:-autolink-force-load>)
 target_link_libraries(swift_Builtin_float PRIVATE
   $<$<PLATFORM_ID:Windows>:ClangModules>
   swiftCore)
 
 install(TARGETS swift_Builtin_float
+  EXPORT SwiftOverlayTargets
   ARCHIVE DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
   LIBRARY DESTINATION "${SwiftOverlay_INSTALL_LIBDIR}"
   RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/apple-common.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/apple-common.cmake
new file mode 100644
index 0000000000000..7d12600d66551
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/apple-common.cmake
@@ -0,0 +1,9 @@
+set(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+set(BUILD_SHARED_LIBS YES CACHE BOOL "")
+set(SwiftOverlay_INSTALL_NESTED_SUBDIR OFF CACHE BOOL "")
+set(SwiftOverlay_ENABLE_LIBRARY_EVOLUTION ON CACHE BOOL "")
+set(SwiftOverlay_ENABLE_BACKDEPLOYMENT_SUPPORT ON CACHE BOOL "")
+
+set(CMAKE_CXX_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_C_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_Swift_FLAGS_MINSIZEREL "-Osize -g" CACHE STRING "")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..ae24d97764daa
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
new file mode 100644
index 0000000000000..1abed5f91b6aa
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
new file mode 100644
index 0000000000000..67641eca76a51
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
@@ -0,0 +1,13 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR freestanding CACHE STRING "")
+set(CMAKE_BUILD_TYPE MinSizeRel CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
new file mode 100644
index 0000000000000..cb68431415894
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftOverlay_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftOverlay_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftOverlay_COMPILER_VARIANT_TARGET "arm64-apple-ios${SwiftOverlay_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..3fd83a015d1ea
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..d736e811590f5
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..4460ad2964b69
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
new file mode 100644
index 0000000000000..93f3f0b2d2de4
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
new file mode 100644
index 0000000000000..640e274535d9a
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64_32 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
new file mode 100644
index 0000000000000..b8f623468d603
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
new file mode 100644
index 0000000000000..64e842e8f9240
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftOverlay_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftOverlay_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftOverlay_COMPILER_VARIANT_TARGET "arm64e-apple-ios${SwiftOverlay_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
new file mode 100644
index 0000000000000..ddbe7c4371305
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-XROS.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
new file mode 100644
index 0000000000000..2c30d3335bb15
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR xros CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
new file mode 100644
index 0000000000000..ec5c239c808b0
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..a4cb83b667cc2
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
new file mode 100644
index 0000000000000..5e951ed23ef8a
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftOverlay_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftOverlay_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftOverlay_COMPILER_VARIANT_TARGET "x86_64-apple-ios${SwiftOverlay_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..7863d93d416bb
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..b6c469cfd6c65
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..2a206f8574844
--- /dev/null
+++ b/Runtimes/Overlay/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftOverlay_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftOverlay_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Overlay/cmake/interface/SwiftOverlayConfig.cmake.in b/Runtimes/Overlay/cmake/interface/SwiftOverlayConfig.cmake.in
new file mode 100644
index 0000000000000..eaabdc1972d67
--- /dev/null
+++ b/Runtimes/Overlay/cmake/interface/SwiftOverlayConfig.cmake.in
@@ -0,0 +1,4 @@
+@PACKAGE_INIT@
+include("${CMAKE_CURRENT_LIST_DIR}/SwiftOverlayTargets.cmake")
+
+set(SwiftOverlay_ENABLE_REFLECTION  @SwiftOverlay_ENABLE_REFLECTION@)
diff --git a/Runtimes/Overlay/cmake/modules/CatalystSupport.cmake b/Runtimes/Overlay/cmake/modules/CatalystSupport.cmake
new file mode 100644
index 0000000000000..69c341a1d58e6
--- /dev/null
+++ b/Runtimes/Overlay/cmake/modules/CatalystSupport.cmake
@@ -0,0 +1,48 @@
+include(CheckCompilerFlag)
+
+# Add flags for generating the zippered target variant in the build
+
+# Initialize `${PROJECT_NAME}_VARIANT_MODULE_TRIPLE` if the driver is able to emit
+# modules for the target variant.
+
+if(${PROJECT_NAME}_COMPILER_VARIANT_TARGET)
+  add_compile_options(
+    "$<$<COMPILE_LANGUAGE:C,CXX>:SHELL:-darwin-target-variant ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>"
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-target-variant ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>"
+
+    # TODO: Remove me once we have a driver with
+    #   https://github.com/swiftlang/swift-driver/pull/1803
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xclang-linker -darwin-target-variant -Xclang-linker ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>")
+
+  add_link_options(
+    "$<$<LINK_LANGUAGE:C,CXX>:SHELL:-darwin-target-variant ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>"
+    "$<$<LINK_LANGUAGE:Swift>:SHELL:-target-variant ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>"
+
+    # TODO: Remove me once we have a driver with
+    #   https://github.com/swiftlang/swift-driver/pull/1803
+    "$<$<LINK_LANGUAGE:Swift>:SHELL:-Xclang-linker -darwin-target-variant -Xclang-linker ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>")
+
+  # TODO: Once we are guaranteed to have a driver with the variant module path
+  #       support everywhere, we should integrate this into PlatformInfo.cmake
+  check_compiler_flag(Swift "-emit-variant-module-path ${CMAKE_CURRENT_BINARY_DIR}/CompilerID/variant.swiftmodule" HAVE_Swift_VARIANT_MODULE_PATH_FLAG)
+  if(HAVE_Swift_VARIANT_MODULE_PATH_FLAG)
+    # Get variant module triple
+    set(module_triple_command "${CMAKE_Swift_COMPILER}" -print-target-info -target ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET})
+    execute_process(COMMAND ${module_triple_command} OUTPUT_VARIABLE target_info_json)
+    message(CONFIGURE_LOG "Swift target variant info: ${target_info_json}")
+
+
+    string(JSON module_triple GET "${target_info_json}" "target" "moduleTriple")
+    set(${PROJECT_NAME}_VARIANT_MODULE_TRIPLE "${module_triple}" CACHE STRING "Triple used for installed swift{module,interface} files for the target variant")
+    mark_as_advanced(${PROJECT_NAME}_VARIANT_MODULE_TRIPLE)
+    message(CONFIGURE_LOG "Swift target variant module triple: ${module_triple}")
+  endif()
+
+  if(${PROJECT_NAME}_EXPERIMENTAL_EMIT_VARIANT_MODULE)
+    check_compiler_flag(Swift "-experimental-emit-variant-module" HAVE_Swift_EMIT_VARIANT_MODULE_FLAG)
+    if(HAVE_Swift_EMIT_VARIANT_MODULE_FLAG)
+    add_compile_options(
+        "$<$<COMPILE_LANGUAGE:Swift>:-experimental-emit-variant-module>")
+    endif()
+  endif()
+endif()
diff --git a/Runtimes/Overlay/cmake/modules/DefaultSettings.cmake b/Runtimes/Overlay/cmake/modules/DefaultSettings.cmake
index 1b9c4b6f991c9..259f24aa20a18 100644
--- a/Runtimes/Overlay/cmake/modules/DefaultSettings.cmake
+++ b/Runtimes/Overlay/cmake/modules/DefaultSettings.cmake
@@ -26,12 +26,16 @@ endmacro()
 
 if(APPLE)
   set(SwiftOverlay_ENABLE_REFLECTION_default ON)
+  set(SwiftOverlay_ENABLE_CXX_INTEROP_default OFF)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "WASM")
   set(SwiftOverlay_ENABLE_REFLECTION_default OFF)
+  set(SwiftOverlay_ENABLE_CXX_INTEROP_default OFF)
 elseif(LINUX OR ANDROID OR BSD)
   set(SwiftOverlay_ENABLE_REFLECTION_default OFF)
+  set(SwiftOverlay_ENABLE_CXX_INTEROP_default OFF)
 elseif(WIN32)
-  set(SwiftOverlay_ENABLE_REFLECTION_default OFF)
+  set(SwiftOverlay_ENABLE_REFLECTION_default ON)
+  set(SwiftOverlay_ENABLE_CXX_INTEROP_default OFF)
 endif()
 
 include("${SwiftOverlay_VENDOR_MODULE_DIR}/DefaultSettings.cmake" OPTIONAL)
diff --git a/Runtimes/Overlay/cmake/modules/EmitSwiftInterface.cmake b/Runtimes/Overlay/cmake/modules/EmitSwiftInterface.cmake
index 95aa11017794a..df4a7c51afef6 100644
--- a/Runtimes/Overlay/cmake/modules/EmitSwiftInterface.cmake
+++ b/Runtimes/Overlay/cmake/modules/EmitSwiftInterface.cmake
@@ -8,61 +8,61 @@
 function(emit_swift_interface target)
   # Generate the target-variant binary swift module when performing zippered
   # build
+  # Clean this up once CMake has nested swiftmodules in the build directory:
+  # https://gitlab.kitware.com/cmake/cmake/-/merge_requests/10664
+  # https://cmake.org/cmake/help/git-stage/policy/CMP0195.html
+
+  # We can't expand the Swift_MODULE_NAME target property in a generator
+  # expression or it will fail saying that the target doesn't exist.
+  get_target_property(module_name ${target} Swift_MODULE_NAME)
+  if(NOT module_name)
+    set(module_name ${target})
+  endif()
+  set(module_directory "${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule")
+  # Account for an existing swiftmodule file
+  # generated with the previous logic
+  if(EXISTS "${module_directory}" AND NOT IS_DIRECTORY "${module_directory}")
+    message(STATUS "Removing regular file '${module_directory}' to support nested swiftmodule generation")
+    file(REMOVE ${module_directory})
+  endif()
+  target_compile_options(${target} PRIVATE
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-module-path ${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.swiftmodule>")
+  set_property(TARGET "${target}" APPEND PROPERTY ADDITIONAL_CLEAN_FILES
+    "${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.swiftmodule"
+    "${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.swiftdoc"
+    "${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.swiftsourceinfo")
   if(SwiftOverlay_VARIANT_MODULE_TRIPLE)
-    set(variant_module_tmp_dir "${CMAKE_CURRENT_BINARY_DIR}/${target}-${SwiftOverlay_VARIANT_MODULE_TRIPLE}")
-    file(MAKE_DIRECTORY "${variant_module_tmp_dir}")
     target_compile_options(${target} PRIVATE
-      "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-path ${variant_module_tmp_dir}/${target}.swiftmodule>")
+      "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-path ${module_directory}/${SwiftOverlay_VARIANT_MODULE_TRIPLE}.swiftmodule>")
+    set_property(TARGET "${target}" APPEND PROPERTY ADDITIONAL_CLEAN_FILES
+      "${module_directory}/${SwiftOverlay_VARIANT_MODULE_TRIPLE}.swiftmodule"
+      "${module_directory}/${SwiftOverlay_VARIANT_MODULE_TRIPLE}.swiftdoc"
+      "${module_directory}/${SwiftOverlay_VARIANT_MODULE_TRIPLE}.swiftsourceinfo")
   endif()
+  add_custom_command(OUTPUT "${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.swiftmodule"
+    DEPENDS ${target})
+  target_sources(${target}
+    INTERFACE
+      $<BUILD_INTERFACE:${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.swiftmodule>)
 
   # Generate textual swift interfaces is library-evolution is enabled
   if(SwiftOverlay_ENABLE_LIBRARY_EVOLUTION)
     target_compile_options(${target} PRIVATE
-      $<$<COMPILE_LANGUAGE:Swift>:-emit-module-interface-path$<SEMICOLON>${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftinterface>
-      $<$<COMPILE_LANGUAGE:Swift>:-emit-private-module-interface-path$<SEMICOLON>${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.private.swiftinterface>
-      $<$<COMPILE_LANGUAGE:Swift>:-library-level$<SEMICOLON>api>
-      $<$<COMPILE_LANGUAGE:Swift>:-Xfrontend$<SEMICOLON>-require-explicit-availability=ignore>)
-
-      # Emit catalyst swiftmodules and interfaces
-      if(SwiftOverlay_VARIANT_MODULE_TRIPLE)
-        target_compile_options(${target} PRIVATE
-          "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-interface-path ${variant_module_tmp_dir}/${target}.swiftinterface>"
-          "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-private-module-interface-path ${variant_module_tmp_dir}/${target}.private.swiftinterface>")
-      endif()
-  endif()
-endfunction()
-
-# Install the generated swift interface file for the target if library evolution
-# is enabled.
-function(install_swift_interface target)
-  # Install binary swift modules
-  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule"
-    RENAME "${SwiftOverlay_MODULE_TRIPLE}.swiftmodule"
-    DESTINATION "${SwiftOverlay_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule")
-  if(SwiftOverlay_VARIANT_MODULE_TRIPLE)
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${target}-${SwiftOverlay_VARIANT_MODULE_TRIPLE}/${target}.swiftmodule"
-      RENAME "${SwiftOverlay_VARIANT_MODULE_TRIPLE}.swiftmodule"
-      DESTINATION "${SwiftOverlay_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule")
-  endif()
-
-  # Install Swift interfaces if library-evolution is enabled
-  if(SwiftOverlay_ENABLE_LIBRARY_EVOLUTION)
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftinterface"
-      RENAME "${SwiftOverlay_MODULE_TRIPLE}.swiftinterface"
-      DESTINATION "${SwiftOverlay_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule")
-
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.private.swiftinterface"
-      RENAME "${SwiftOverlay_MODULE_TRIPLE}.private.swiftinterface"
-      DESTINATION "${SwiftOverlay_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule")
-
-    # Install catalyst interface files
+      $<$<COMPILE_LANGUAGE:Swift>:-emit-module-interface-path$<SEMICOLON>${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.swiftinterface>
+      $<$<COMPILE_LANGUAGE:Swift>:-emit-private-module-interface-path$<SEMICOLON>${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.private.swiftinterface>)
+    set_property(TARGET "${target}" APPEND PROPERTY ADDITIONAL_CLEAN_FILES
+      "${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.swiftinterface"
+      "${module_directory}/${SwiftOverlay_MODULE_TRIPLE}.private.swiftinterface")
     if(SwiftOverlay_VARIANT_MODULE_TRIPLE)
-      install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${target}-${SwiftOverlay_VARIANT_MODULE_TRIPLE}/${target}.swiftinterface"
-        RENAME "${SwiftOverlay_VARIANT_MODULE_TRIPLE}.swiftinterface"
-        DESTINATION "${SwiftOverlay_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule")
-      install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${target}-${SwiftOverlay_VARIANT_MODULE_TRIPLE}/${target}.private.swiftinterface"
-        RENAME "${SwiftOverlay_VARIANT_MODULE_TRIPLE}.private.swiftinterface"
-        DESTINATION "${SwiftOverlay_INSTALL_SWIFTMODULEDIR}/$<TARGET_PROPERTY:${target},Swift_MODULE_NAME>.swiftmodule")
+      target_compile_options(${target} PRIVATE
+        "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-interface-path ${module_directory}/${SwiftOverlay_VARIANT_MODULE_TRIPLE}.swiftinterface>"
+        "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-private-module-interface-path ${module_directory}/${SwiftOverlay_VARIANT_MODULE_TRIPLE}.private.swiftinterface>")
+    set_property(TARGET "${target}" APPEND PROPERTY ADDITIONAL_CLEAN_FILES
+      "${module_directory}/${SwiftOverlay_VARIANT_MODULE_TRIPLE}.swiftinterface"
+      "${module_directory}/${SwiftOverlay_VARIANT_MODULE_TRIPLE}.private.swiftinterface")
     endif()
+    target_compile_options(${target} PRIVATE
+      $<$<COMPILE_LANGUAGE:Swift>:-library-level$<SEMICOLON>api>
+      $<$<COMPILE_LANGUAGE:Swift>:-Xfrontend$<SEMICOLON>-require-explicit-availability=ignore>)
   endif()
 endfunction()
diff --git a/Runtimes/Overlay/cmake/modules/ExperimentalFeatures.cmake b/Runtimes/Overlay/cmake/modules/ExperimentalFeatures.cmake
new file mode 100644
index 0000000000000..311630bac1ce4
--- /dev/null
+++ b/Runtimes/Overlay/cmake/modules/ExperimentalFeatures.cmake
@@ -0,0 +1,9 @@
+add_compile_options(
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NoncopyableGenerics2>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SuppressedAssociatedTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SE427NoInferenceOnExtension>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NonescapableTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature InoutLifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependenceMutableAccessors>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-upcoming-feature MemberImportVisibility>")
diff --git a/Runtimes/Overlay/cmake/modules/InstallSwiftInterface.cmake b/Runtimes/Overlay/cmake/modules/InstallSwiftInterface.cmake
new file mode 100644
index 0000000000000..8a7fbfe113c4b
--- /dev/null
+++ b/Runtimes/Overlay/cmake/modules/InstallSwiftInterface.cmake
@@ -0,0 +1,13 @@
+
+# Install the generated swift interface files for the target.
+function(install_swift_interface target)
+  # Swiftmodules are already in the directory structure
+  get_target_property(module_name ${target} Swift_MODULE_NAME)
+  if(NOT module_name)
+    set(module_name ${target})
+  endif()
+
+  install(DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule"
+    DESTINATION "${SwiftOverlay_INSTALL_SWIFTMODULEDIR}"
+    COMPONENT SwiftOverlay_development)
+endfunction()
diff --git a/Runtimes/Resync.cmake b/Runtimes/Resync.cmake
index 59d95df91d14e..92e08c7821d8c 100644
--- a/Runtimes/Resync.cmake
+++ b/Runtimes/Resync.cmake
@@ -56,6 +56,8 @@ function(copy_library_sources name from_prefix to_prefix)
     "${ARG_ROOT}/${from_prefix}/${name}/*.c"
     "${ARG_ROOT}/${from_prefix}/${name}/*.mm"
     "${ARG_ROOT}/${from_prefix}/${name}/*.m"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.S"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.asm"
     "${ARG_ROOT}/${from_prefix}/${name}/*.def"
     "${ARG_ROOT}/${from_prefix}/${name}/*.gyb"
     "${ARG_ROOT}/${from_prefix}/${name}/*.apinotes"
@@ -86,6 +88,8 @@ set(CoreLibs
   CommandLineSupport
   core
   SwiftOnoneSupport
+  RemoteInspection
+  SwiftRemoteMirror
   Concurrency
   Concurrency/InternalShims)
 
@@ -96,23 +100,71 @@ endforeach()
 message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Core/Info.plist.in")
 copy_files("" "Core" FILES "Info.plist.in")
 
+message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Supplemental/Distributed/Info.plist.in")
+copy_files("" "Supplemental/Distributed" FILES "Info.plist.in")
+
+message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Supplemental/Differentiation/Info.plist.in")
+copy_files("" "Supplemental/Differentiation" FILES "Info.plist.in")
+
+message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Supplemental/Observation/Info.plist.in")
+copy_files("" "Supplemental/Observation" FILES "Info.plist.in")
+
+message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Supplemental/StringProcessing/Info.plist.in")
+copy_files("" "Supplemental/StringProcessing" FILES "Info.plist.in")
+
+message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Supplemental/Synchronization/Info.plist.in")
+copy_files("" "Supplemental/Synchronization" FILES "Info.plist.in")
+
+message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Supplemental/Volatile/Info.plist.in")
+copy_files("" "Supplemental/Volatile" FILES "Info.plist.in")
+
+message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Supplemental/Runtime/Info.plist.in")
+copy_files("" "Supplemental/Runtime" FILES "Info.plist.in")
+
 # Platform Overlays
 
 # Copy magic linker symbols
-copy_library_sources("linker-support" "" "Overlay")
+copy_library_sources("linker-support" "public/ClangOverlays" "Overlay")
 
 message(STATUS "Clang[${StdlibSources}/public/ClangOverlays] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/clang")
 copy_files(public/ClangOverlays Overlay/clang FILES float.swift.gyb)
 
+copy_library_sources("Cxx" "public" "Overlay")
+
+# Android Overlay
+message(STATUS "Android modulemaps[${StdlibSources}/Platform] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Android/clang")
+copy_files(public/Platform Overlay/Android/clang
+  FILES
+    android.modulemap
+    posix_filesystem.apinotes
+    spawn.apinotes
+    SwiftAndroidNDK.h
+    SwiftBionic.h)
+
+message(STATUS "Android Android[${StdlibSources}/Platform] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Android/Android")
+copy_files(public/Platform Overlay/Android/Android
+  FILES
+    Android.swift
+    Platform.swift
+    POSIXError.swift
+    TiocConstants.swift
+    tgmath.swift.gyb)
+
+message(STATUS "Android Math[${StdlibSources}/Platform] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Android/Math")
+copy_files(public/Platform Overlay/Android/Math
+  FILES
+    Math.swift)
+
 # Windows Overlay
 message(STATUS "WinSDK[${StdlibSources}/public/Windows] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/WinSDK")
 copy_files(public/Windows Overlay/Windows/WinSDK FILES WinSDK.swift)
 
-message(STATUS "Windows Modulemaps[${StdlibSources}/Platform] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/clang")
+message(STATUS "Windows modulemaps[${StdlibSources}/Platform] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/clang")
 copy_files(public/Platform Overlay/Windows/clang
   FILES
     ucrt.modulemap
-    winsdk.modulemap
+    winsdk_um.modulemap
+    winsdk_shared.modulemap
     vcruntime.modulemap
     vcruntime.apinotes)
 
@@ -125,12 +177,6 @@ copy_files(public/Platform Overlay/Windows/CRT
     TiocConstants.swift
     tgmath.swift.gyb)
 
-# TODO: Add source directories for the platform overlays, supplemental
-# libraries, and test support libraries.
-
-# Supplemental Libraries
-
-# Copy StringProcessing, RegexParser, RegexBuilder
 if(NOT DEFINED StringProcessing_ROOT_DIR)
   find_path(StringProcessing_ROOT_DIR
     "swift-experimental-string-processing/Package.swift"
@@ -138,6 +184,14 @@ if(NOT DEFINED StringProcessing_ROOT_DIR)
 endif()
 message(STATUS "String Processing Root: ${StringProcessing_ROOT_DIR}")
 
+# Supplemental Libraries
+copy_library_sources(Differentiation "public" "Supplemental")
+copy_library_sources(Distributed "public" "Supplemental")
+copy_library_sources(Observation "public" "Supplemental")
+copy_library_sources(Synchronization "public" "Supplemental")
+copy_library_sources(Volatile "public" "Supplemental")
+copy_library_sources("" "public/RuntimeModule" "Supplemental/Runtime")
+
 copy_library_sources(_RegexParser "Sources" "Supplemental/StringProcessing"
   ROOT "${StringProcessing_ROOT_DIR}/swift-experimental-string-processing")
 copy_library_sources(_StringProcessing "Sources" "Supplemental/StringProcessing"
@@ -146,3 +200,6 @@ copy_library_sources(_CUnicode "Sources" "Supplemental/StringProcessing/_StringP
   ROOT "${StringProcessing_ROOT_DIR}/swift-experimental-string-processing")
 copy_library_sources(RegexBuilder "Sources" "Supplemental/StringProcessing"
   ROOT "${StringProcessing_ROOT_DIR}/swift-experimental-string-processing")
+
+copy_library_sources("linker-support" "" "Supplemental/Differentiation")
+copy_library_sources(include "" "Supplemental/Distributed")
diff --git a/Runtimes/Supplemental/CMakeLists.txt b/Runtimes/Supplemental/CMakeLists.txt
new file mode 100644
index 0000000000000..0b64b98c7c7e1
--- /dev/null
+++ b/Runtimes/Supplemental/CMakeLists.txt
@@ -0,0 +1,125 @@
+cmake_minimum_required(VERSION 3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
+
+project(SwiftRuntime LANGUAGES Swift C CXX)
+
+include(ExternalProject)
+include(GNUInstallDirs)
+
+set(SwiftRuntime_SWIFTC_SOURCE_DIR "${PROJECT_SOURCE_DIR}/../../")
+
+foreach(lib ${Swift_ENABLE_RUNTIMES})
+  string(TOLOWER ${lib} name)
+  set(SwiftRuntime_ENABLE_${name} YES)
+endforeach()
+
+if(SwiftCore_DIR)
+  set(SwiftCore_DIR_FLAG "-DSwiftCore_DIR=${SwiftCore_DIR}")
+endif()
+
+if(CMAKE_MAKE_PROGRAM)
+  set(MAKE_PROGRAM_FLAG "-DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}")
+endif()
+
+set(COMMON_OPTIONS
+  -DBUILD_SHARED_LIBS=${BUILD_SHARED_LIBS}
+  -DSwift_SDKROOT=${Swift_SDKROOT}
+  -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
+  -DCMAKE_INSTALL_LIBDIR=${CMAKE_INSTALL_LIBDIR}
+  -DCMAKE_INSTALL_NAME_DIR=${CMAKE_INSTALL_NAME_DIR}
+  -DCMAKE_BUILD_WITH_INSTALL_NAME_DIR=${CMAKE_BUILD_WITH_INSTALL_NAME_DIR}
+  -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
+  -DCMAKE_COLOR_DIAGNOSTICS=${CMAKE_COLOR_DIAGNOSTICS}
+  -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
+  -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
+  -DCMAKE_Swift_COMPILER=${CMAKE_Swift_COMPILER}
+  -DCMAKE_C_COMPILER_TARGET=${CMAKE_C_COMPILER_TARGET}
+  -DCMAKE_CXX_COMPILER_TARGET=${CMAKE_CXX_COMPILER_TARGET}
+  -DCMAKE_ASM_COMPILER_TARGET=${CMAKE_ASM_COMPILER_TARGET}
+  -DCMAKE_Swift_COMPILER_TARGET=${CMAKE_Swift_COMPILER_TARGET}
+  -DCMAKE_FIND_PACKAGE_PREFER_CONFIG=${CMAKE_FIND_PACKAGE_PREFER_CONFIG}
+  ${SwiftCore_DIR_FLAG}
+  ${MAKE_PROGRAM_FLAG})
+
+# StringProcessing
+if(SwiftRuntime_ENABLE_stringprocessing)
+  ExternalProject_Add(StringProcessing
+    PREFIX "StringProcessing"
+    SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/StringProcessing"
+    INSTALL_DIR "${CMAKE_INSTALL_PREFIX}"
+    INSTALL_COMMAND ""
+    # To ensure incremental builds work as expected
+    BUILD_ALWAYS 1
+    CMAKE_ARGS
+      ${COMMON_OPTIONS})
+endif()
+
+# Synchronization
+if(SwiftRuntime_ENABLE_synchronization)
+  ExternalProject_Add(Synchronization
+    PREFIX "Synchronization"
+    SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/Synchronization"
+    INSTALL_DIR "${CMAKE_INSTALL_PREFIX}"
+    INSTALL_COMMAND ""
+    # To ensure incremental builds work as expected
+    BUILD_ALWAYS 1
+    CMAKE_ARGS
+      ${COMMON_OPTIONS})
+endif()
+
+# Distributed
+if(SwiftRuntime_ENABLE_distributed)
+  ExternalProject_Add(Distributed
+    PREFIX "Distributed"
+    SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/Distributed"
+    INSTALL_DIR "${CMAKE_INSTALL_PREFIX}"
+    INSTALL_COMMAND ""
+    # To ensure incremental builds work as expected
+    BUILD_ALWAYS 1
+    CMAKE_ARGS
+      ${COMMON_OPTIONS})
+endif()
+
+
+# Differentiation
+if(SwiftRuntime_ENABLE_differentiation)
+  ExternalProject_Add(Differentiation
+    PREFIX "Differentiation"
+    SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/Differentiation"
+    INSTALL_DIR "${CMAKE_INSTALL_PREFIX}"
+    INSTALL_COMMAND ""
+    # To ensure incremental builds work as expected
+    BUILD_ALWAYS 1
+    CMAKE_ARGS
+      ${COMMON_OPTIONS})
+endif()
+
+# Observation
+if(SwiftRuntime_ENABLE_observation)
+  ExternalProject_Add(Observation
+    PREFIX "Observation"
+    SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/Observation"
+    INSTALL_DIR "${CMAKE_INSTALL_PREFIX}"
+    INSTALL_COMMAND ""
+    # To ensure incremental builds work as expected
+    BUILD_ALWAYS 1
+    CMAKE_ARGS
+      ${COMMON_OPTIONS})
+endif()
+
+# Runtime
+if(SwiftRuntime_ENABLE_runtime)
+  ExternalProject_Add(Runtime
+    PREFIX "Runtime"
+    SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/Runtime"
+    INSTALL_DIR "${CMAKE_INSTALL_PREFIX}"
+    INSTALL_COMMAND ""
+    # To ensure incremental builds work as expected
+    BUILD_ALWAYS 1
+    CMAKE_ARGS
+      ${COMMON_OPTIONS})
+endif()
diff --git a/Runtimes/Supplemental/Differentiation/CMakeLists.txt b/Runtimes/Supplemental/Differentiation/CMakeLists.txt
new file mode 100644
index 0000000000000..3e0b42124aeff
--- /dev/null
+++ b/Runtimes/Supplemental/Differentiation/CMakeLists.txt
@@ -0,0 +1,139 @@
+cmake_minimum_required(VERSION 3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
+
+if(POLICY CMP0157 AND CMAKE_Swift_COMPILER_USE_OLD_DRIVER)
+  cmake_policy(SET CMP0157 OLD)
+endif()
+
+list(APPEND CMAKE_MODULE_PATH
+  "${CMAKE_SOURCE_DIR}/../cmake/modules"
+  "${CMAKE_SOURCE_DIR}/../../cmake/modules")
+
+include(SwiftProjectVersion)
+project(SwiftDifferentiation
+  LANGUAGES Swift C
+  VERSION ${SWIFT_RUNTIME_VERSION})
+
+if(NOT PROJECT_IS_TOP_LEVEL)
+  message(SEND_ERROR "Swift Differentiation must build as a standalone project")
+endif()
+
+set(CMAKE_POSITION_INDEPENDENT_CODE YES)
+set(CMAKE_Swift_LANGUAGE_VERSION 5)
+
+set(${PROJECT_NAME}_SWIFTC_SOURCE_DIR
+  "${PROJECT_SOURCE_DIR}/../../../"
+  CACHE FILEPATH "Path to the root source directory of the Swift compiler")
+
+# Hook point for vendor-specific extensions to the build system
+# Allowed extension points:
+#   - DefaultSettings.cmake
+#   - Settings.cmake
+set(${PROJECT_NAME}_VENDOR_MODULE_DIR "${CMAKE_SOURCE_DIR}/../cmake/modules/vendor"
+  CACHE FILEPATH "Location for private build system extension")
+
+find_package(SwiftCore REQUIRED)
+find_package(SwiftOverlay REQUIRED)
+
+include(GNUInstallDirs)
+
+include(AvailabilityMacros)
+include(EmitSwiftInterface)
+include(InstallSwiftInterface)
+include(PlatformInfo)
+include(gyb)
+include(ResourceEmbedding)
+include(CatalystSupport)
+
+option(${PROJECT_NAME}_INSTALL_NESTED_SUBDIR "Install libraries under a platform and architecture subdirectory" ON)
+set(${PROJECT_NAME}_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}>" CACHE STRING "")
+set(${PROJECT_NAME}_INSTALL_SWIFTMODULEDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}>" CACHE STRING "")
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/Settings.cmake" OPTIONAL)
+
+option(${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION "Generate ABI resilient runtime libraries"
+  ${SwiftCore_ENABLE_LIBRARY_EVOLUTION})
+
+option(${PROJECT_NAME}_ENABLE_VECTOR_TYPES "Enable vector support"
+  ${SwiftCore_ENABLE_VECTOR_TYPES})
+
+
+add_compile_options(
+  $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>
+  $<$<COMPILE_LANGUAGE:Swift>:-nostdlibimport>
+  $<$<COMPILE_LANGUAGE:Swift>:-parse-stdlib>
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-library-level api>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NoncopyableGenerics2>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SuppressedAssociatedTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SE427NoInferenceOnExtension>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NonescapableTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature MemberImportVisibility>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enforce-exclusivity=unchecked>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
+  $<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>)
+
+# LNK4049: symbol 'symbol' defined in 'filename.obj' is imported
+# LNK4286: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj'
+# LNK4217: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj' in function 'function'
+#
+# We cannot selectively filter the linker warnings as we do not use the MSVC
+# frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
+# a compromise, treat all linker warnings as errors.
+# FIXME(#83444) - enable this once we fix DLL storage for
+# `_fatalErrorForwardModeDifferentiationDisabled`
+# add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Android,Linux>:LINKER:-z,defs>)
+
+if(SwiftDifferentiation_ENABLE_VECTOR_TYPES)
+  gyb_expand(SIMDDifferentiation.swift.gyb SIMDDifferentiation.swift)
+endif()
+gyb_expand(TgmathDerivatives.swift.gyb TgmathDerivatives.swift)
+gyb_expand(FloatingPointDifferentiation.swift.gyb
+  FloatingPointDifferentiation.swift)
+
+add_library(swift_Differentiation
+  AnyDifferentiable.swift
+  ArrayDifferentiation.swift
+  Differentiable.swift
+  DifferentialOperators.swift
+  DifferentiationUtilities.swift
+  OptionalDifferentiation.swift
+  $<$<BOOL:${${PROJECT_NAME}_ENABLE_VECTOR_TYPES}>:SIMDDifferentiation.swift>
+  TgmathDerivatives.swift
+  FloatingPointDifferentiation.swift
+  linker-support/magic-symbols-for-install-name.c)
+
+if(APPLE AND BUILD_SHARED_LIBS)
+  target_link_options(swift_Differentiation PRIVATE
+    "SHELL:-Xlinker -headerpad_max_install_names")
+endif()
+
+set_target_properties(swift_Differentiation PROPERTIES
+  Swift_MODULE_NAME _Differentiation)
+
+target_link_libraries(swift_Differentiation PRIVATE
+  swiftCore
+  $<$<PLATFORM_ID:Android>:swiftAndroid>
+  $<$<PLATFORM_ID:Windows>:swiftCRT>)
+
+
+install(TARGETS swift_Differentiation
+  EXPORT SwiftSupplementalTargets
+  COMPONENT ${PROJECT_NAME}_runtime
+  ARCHIVE DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swift_Differentiation)
+install_swift_interface(swift_Differentiation)
+
+# Configure plist creation for Darwin platforms.
+generate_plist(swift_Differentiation "${CMAKE_PROJECT_VERSION}" swift_Differentiation)
+embed_manifest(swift_Differentiation)
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/swift_Differentiation.cmake" OPTIONAL)
diff --git a/Runtimes/Supplemental/Distributed/CMakeLists.txt b/Runtimes/Supplemental/Distributed/CMakeLists.txt
new file mode 100644
index 0000000000000..bded5de9320fa
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/CMakeLists.txt
@@ -0,0 +1,157 @@
+cmake_minimum_required(VERSION 3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
+
+if(POLICY CMP0157 AND CMAKE_Swift_COMPILER_USE_OLD_DRIVER)
+  cmake_policy(SET CMP0157 OLD)
+endif()
+
+list(APPEND CMAKE_MODULE_PATH
+  "${CMAKE_SOURCE_DIR}/../cmake/modules"
+  "${CMAKE_SOURCE_DIR}/../../cmake/modules")
+
+include(LanguageVersions)
+include(SwiftProjectVersion)
+project(SwiftDistributed
+  LANGUAGES C CXX Swift
+  VERSION ${SWIFT_RUNTIME_VERSION})
+
+if(NOT PROJECT_IS_TOP_LEVEL)
+  message(SEND_ERROR "Swift Distributed must build as a standalone project")
+endif()
+
+set(CMAKE_POSITION_INDEPENDENT_CODE YES)
+
+set(CMAKE_C_VISIBILITY_PRESET "hidden")
+set(CMAKE_CXX_VISIBILITY_PRESET "hidden")
+set(CMAKE_VISIBILITY_INLINES_HIDDEN YES)
+
+set(${PROJECT_NAME}_SWIFTC_SOURCE_DIR
+  "${PROJECT_SOURCE_DIR}/../../../"
+  CACHE FILEPATH "Path to the root source directory of the Swift compiler")
+
+# Hook point for vendor-specific extensions to the build system
+# Allowed extension points:
+#   - DefaultSettings.cmake
+#   - Settings.cmake
+set(${PROJECT_NAME}_VENDOR_MODULE_DIR "${CMAKE_SOURCE_DIR}/../cmake/modules/vendor"
+  CACHE FILEPATH "Location for private build system extension")
+
+find_package(SwiftCore REQUIRED)
+find_package(SwiftOverlay REQUIRED)
+
+include(GNUInstallDirs)
+
+include(AvailabilityMacros)
+include(EmitSwiftInterface)
+include(InstallSwiftInterface)
+include(PlatformInfo)
+include(ResourceEmbedding)
+include(CatalystSupport)
+include(SwiftCallingConventions)
+
+option(${PROJECT_NAME}_INSTALL_NESTED_SUBDIR "Install libraries under a platform and architecture subdirectory" ON)
+set(${PROJECT_NAME}_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}>" CACHE STRING "")
+set(${PROJECT_NAME}_INSTALL_SWIFTMODULEDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}>" CACHE STRING "")
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/Settings.cmake" OPTIONAL)
+
+option(${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION "Generate ABI resilient runtime libraries"
+  ${SwiftCore_ENABLE_LIBRARY_EVOLUTION})
+
+option(${PROJECT_NAME}_ENABLE_PRESPECIALIZATION "Enable generic metadata prespecialization"
+  ${SwiftCore_ENABLE_PRESPECIALIZATION})
+
+add_compile_options(
+  $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>
+  $<$<COMPILE_LANGUAGE:Swift>:-nostdlibimport>
+  $<$<COMPILE_LANGUAGE:Swift>:-strict-memory-safety>
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NoncopyableGenerics2>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SuppressedAssociatedTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SE427NoInferenceOnExtension>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NonescapableTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature InoutLifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependenceMutableAccessors>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-upcoming-feature MemberImportVisibility>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enforce-exclusivity=unchecked>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-lexical-lifetimes=false>"
+  "$<$<COMPILE_LANGUAGE:Swift>:-warn-implicit-overrides>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
+
+# LNK4049: symbol 'symbol' defined in 'filename.obj' is imported
+# LNK4286: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj'
+# LNK4217: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj' in function 'function'
+#
+# We cannot selectively filter the linker warnings as we do not use the MSVC
+# frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
+# a compromise, treat all linker warnings as errors.
+add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Android,Linux>:LINKER:-z,defs>)
+
+add_library(swiftDistributed
+  DistributedActor.cpp
+  DistributedActor.swift
+  DistributedActorSystem.swift
+  DistributedAssertions.swift
+  DistributedDefaultExecutor.swift
+  DistributedMacros.swift
+  DistributedMetadata.swift
+  LocalTestingDistributedActorSystem.swift)
+
+set_target_properties(swiftDistributed PROPERTIES
+  Swift_MODULE_NAME Distributed)
+cmake_policy(GET CMP0157 Policy157Enabled)
+if(Policy157Enabled STREQUAL NEW)
+  set_target_properties(swiftDistributed PROPERTIES
+    LINKER_LANGUAGE CXX)
+endif()
+
+target_compile_definitions(swiftDistributed PRIVATE
+  $<$<COMPILE_LANGUAGE:C,CXX>:-DSWIFT_TARGET_LIBRARY_NAME=swiftDistributed>)
+target_compile_options(swiftDistributed PRIVATE
+  $<$<COMPILE_LANGUAGE:Swift>:-parse-stdlib>
+  $<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature AllowUnsafeAttribute>)
+
+if(APPLE AND BUILD_SHARED_LIBS)
+  target_link_options(swiftDistributed PRIVATE
+    "SHELL:-Xlinker -headerpad_max_install_names")
+endif()
+
+target_include_directories(swiftDistributed PRIVATE
+  # FIXME: Use of `swift/Runtime/...`, `swift/ABI/...`, and `swift/Demangling/...`
+  "${${PROJECT_NAME}_SWIFTC_SOURCE_DIR}/include"
+  # For `swift/runtime/CMakeConfig.h`, which should be generated
+  # by the Core build system.
+  "${${PROJECT_NAME}_PATH_TO_SWIFT_RUNTIME_HEADERS}"
+  # For llvm/support headers
+  "${PROJECT_SOURCE_DIR}/include")
+
+target_link_libraries(swiftDistributed PRIVATE
+  swiftShims
+  swiftCore
+  swift_Concurrency
+  swift_Builtin_float
+  $<$<PLATFORM_ID:Android>:swiftAndroid>
+  $<$<PLATFORM_ID:Windows>:swiftWinSDK>)
+
+install(TARGETS swiftDistributed
+  EXPORT SwiftDistributedTargets
+  COMPONENT ${PROJECT_NAME}_runtime
+  ARCHIVE DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swiftDistributed)
+install_swift_interface(swiftDistributed)
+
+# Configure plist creation for Darwin platforms.
+generate_plist(swiftDistributed "${CMAKE_PROJECT_VERSION}" swiftDistributed)
+embed_manifest(swiftDistributed)
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/swiftDistributed.cmake" OPTIONAL)
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/apple-common.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/apple-common.cmake
new file mode 100644
index 0000000000000..dd56f854c2593
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/apple-common.cmake
@@ -0,0 +1,7 @@
+set(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+set(BUILD_SHARED_LIBS YES CACHE BOOL "")
+set(SwiftDistributed_INSTALL_NESTED_SUBDIR OFF CACHE BOOL "")
+
+set(CMAKE_CXX_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_C_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_Swift_FLAGS_MINSIZEREL "-Osize -g" CACHE STRING "")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..40c066b36d36d
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
new file mode 100644
index 0000000000000..9c88909940f29
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
new file mode 100644
index 0000000000000..7ba1f319b733f
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
@@ -0,0 +1,14 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR freestanding CACHE STRING "")
+set(CMAKE_BUILD_TYPE MinSizeRel CACHE STRING "")
+set(SwiftDistributed_SINGLE_THREADED_MODE YES CACHE BOOL "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
new file mode 100644
index 0000000000000..040412a0a2c0f
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftDistributed_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftDistributed_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftDistributed_COMPILER_VARIANT_TARGET "arm64-apple-ios${SwiftDistributed_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..e631faa114542
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..659e8edd9fbfc
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..d1db08d6ae896
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
new file mode 100644
index 0000000000000..1dd20403ef33e
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
new file mode 100644
index 0000000000000..6d6cc83c1b25e
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64_32 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
new file mode 100644
index 0000000000000..d570fc0c249e4
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
new file mode 100644
index 0000000000000..bc5bc7f02f308
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftDistributed_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftDistributed_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftDistributed_COMPILER_VARIANT_TARGET "arm64e-apple-ios${SwiftDistributed_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
new file mode 100644
index 0000000000000..e8789681dd0e6
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-XROS.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
new file mode 100644
index 0000000000000..4bd9e5c555498
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR xros CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
new file mode 100644
index 0000000000000..34175778a6c22
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..66208927e0514
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
new file mode 100644
index 0000000000000..ec3cec9d72854
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftDistributed_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftDistributed_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftDistributed_COMPILER_VARIANT_TARGET "x86_64-apple-ios${SwiftDistributed_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..9be3fa6a6d8ec
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..c215b37455d42
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..15c21b7961e03
--- /dev/null
+++ b/Runtimes/Supplemental/Distributed/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftDistributed_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftDistributed_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/CMakeLists.txt b/Runtimes/Supplemental/Observation/CMakeLists.txt
new file mode 100644
index 0000000000000..98ce40a292f5e
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/CMakeLists.txt
@@ -0,0 +1,134 @@
+cmake_minimum_required(VERSION 3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
+
+if(POLICY CMP0157 AND CMAKE_Swift_COMPILER_USE_OLD_DRIVER)
+  cmake_policy(SET CMP0157 OLD)
+endif()
+
+list(APPEND CMAKE_MODULE_PATH
+  "${CMAKE_SOURCE_DIR}/../cmake/modules"
+  "${CMAKE_SOURCE_DIR}/../../cmake/modules")
+
+include(LanguageVersions)
+include(SwiftProjectVersion)
+project(SwiftObservation
+  LANGUAGES Swift CXX
+  VERSION ${SWIFT_RUNTIME_VERSION})
+
+if(NOT PROJECT_IS_TOP_LEVEL)
+  message(SEND_ERROR "Swift Observation must build as a standalone project")
+endif()
+
+set(CMAKE_POSITION_INDEPENDENT_CODE YES)
+
+set(${PROJECT_NAME}_SWIFTC_SOURCE_DIR
+  "${PROJECT_SOURCE_DIR}/../../../"
+  CACHE FILEPATH "Path to the root source directory of the Swift compiler")
+
+# Hook point for vendor-specific extensions to the build system
+# Allowed extension points:
+#   - DefaultSettings.cmake
+#   - Settings.cmake
+set(${PROJECT_NAME}_VENDOR_MODULE_DIR "${CMAKE_SOURCE_DIR}/../cmake/modules/vendor"
+  CACHE FILEPATH "Location for private build system extension")
+
+find_package(SwiftCore REQUIRED)
+find_package(SwiftOverlay REQUIRED)
+
+include(GNUInstallDirs)
+
+include(AvailabilityMacros)
+include(EmitSwiftInterface)
+include(InstallSwiftInterface)
+include(PlatformInfo)
+include(gyb)
+include(ResourceEmbedding)
+include(CatalystSupport)
+
+option(${PROJECT_NAME}_INSTALL_NESTED_SUBDIR "Install libraries under a platform and architecture subdirectory" ON)
+set(${PROJECT_NAME}_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}>" CACHE STRING "")
+set(${PROJECT_NAME}_INSTALL_SWIFTMODULEDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}>" CACHE STRING "")
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/Settings.cmake" OPTIONAL)
+
+option(${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION "Generate ABI resilient runtime libraries"
+  ${SwiftCore_ENABLE_LIBRARY_EVOLUTION})
+
+option(${PROJECT_NAME}_ENABLE_PRESPECIALIZATION "Enable generic metadata prespecialization"
+  ${SwiftCore_ENABLE_PRESPECIALIZATION})
+
+add_compile_options(
+  $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>
+  $<$<COMPILE_LANGUAGE:Swift>:-nostdlibimport>
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enforce-exclusivity=unchecked>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NoncopyableGenerics2>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SuppressedAssociatedTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SE427NoInferenceOnExtension>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NonescapableTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature InoutLifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependenceMutableAccessors>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-upcoming-feature MemberImportVisibility>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Macros>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature ExtensionMacros>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-lexical-lifetimes=false>"
+  "$<$<COMPILE_LANGUAGE:Swift>:-warn-implicit-overrides>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
+
+# LNK4049: symbol 'symbol' defined in 'filename.obj' is imported
+# LNK4286: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj'
+# LNK4217: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj' in function 'function'
+#
+# We cannot selectively filter the linker warnings as we do not use the MSVC
+# frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
+# a compromise, treat all linker warnings as errors.
+add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Android,Linux>:LINKER:-z,defs>)
+
+add_library(swiftObservation
+  Sources/Observation/Locking.swift
+  Sources/Observation/Observable.swift
+  Sources/Observation/ObservationRegistrar.swift
+  Sources/Observation/ObservationTracking.swift
+  Sources/Observation/Observations.swift
+  Sources/Observation/ThreadLocal.swift
+  Sources/Observation/ThreadLocal.cpp)
+set_target_properties(swiftObservation PROPERTIES
+  Swift_MODULE_NAME Observation)
+# FIXME: We should split out the parts that are needed by the runtime to avoid
+# pulling in headers from the compiler.
+target_include_directories(swiftObservation PRIVATE
+  "${${PROJECT_NAME}_SWIFTC_SOURCE_DIR}/include"
+  # For `swift/runtime/CMakeConfig.h`, which should be generated
+  # by the Core build system.
+  "${${PROJECT_NAME}_PATH_TO_SWIFT_RUNTIME_HEADERS}")
+target_link_libraries(swiftObservation PRIVATE
+  swiftShims
+  swiftCore
+  swift_Concurrency
+  $<$<PLATFORM_ID:Android>:swiftAndroid>
+  $<$<PLATFORM_ID:Linux>:swiftGlibc>
+  $<$<PLATFORM_ID:Windows>:swiftWinSDK>)
+
+install(TARGETS swiftObservation
+  EXPORT SwiftObservationTargets
+  COMPONENT ${PROJECT_NAME}_runtime
+  ARCHIVE DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swiftObservation)
+install_swift_interface(swiftObservation)
+
+# Configure plist creation for Darwin platforms.
+generate_plist(swiftObservation "${CMAKE_PROJECT_VERSION}" swiftObservation)
+embed_manifest(swiftObservation)
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/swiftObservation.cmake" OPTIONAL)
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/apple-common.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/apple-common.cmake
new file mode 100644
index 0000000000000..f037c7905ee3e
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/apple-common.cmake
@@ -0,0 +1,7 @@
+set(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+set(BUILD_SHARED_LIBS YES CACHE BOOL "")
+set(SwiftObservation_INSTALL_NESTED_SUBDIR OFF CACHE BOOL "")
+
+set(CMAKE_CXX_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_C_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_Swift_FLAGS_MINSIZEREL "-Osize -g" CACHE STRING "")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..50fd46931d8e7
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
new file mode 100644
index 0000000000000..2448ed4933479
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
new file mode 100644
index 0000000000000..c8d88765e5610
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
@@ -0,0 +1,14 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR freestanding CACHE STRING "")
+set(CMAKE_BUILD_TYPE MinSizeRel CACHE STRING "")
+set(SwiftObservation_SINGLE_THREADED_MODE YES CACHE BOOL "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
new file mode 100644
index 0000000000000..5506f080048a3
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftObservation_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftObservation_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftObservation_COMPILER_VARIANT_TARGET "arm64-apple-ios${SwiftObservation_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..a191012809e71
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..72dd460ceb151
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..ac200660e1315
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
new file mode 100644
index 0000000000000..64aa23c220f4c
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
new file mode 100644
index 0000000000000..4d085c3b74d53
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64_32 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
new file mode 100644
index 0000000000000..c46319a503423
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
new file mode 100644
index 0000000000000..2aa67902a3979
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftObservation_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftObservation_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftObservation_COMPILER_VARIANT_TARGET "arm64e-apple-ios${SwiftObservation_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
new file mode 100644
index 0000000000000..40d8ca3e36303
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-XROS.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
new file mode 100644
index 0000000000000..e5c3feef70c74
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR xros CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
new file mode 100644
index 0000000000000..2b84e565919f3
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..d4f7b5bc67a6f
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
new file mode 100644
index 0000000000000..3288b4627c585
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftObservation_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftObservation_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftObservation_COMPILER_VARIANT_TARGET "x86_64-apple-ios${SwiftObservation_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..00ae81dd841b5
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..d86c8c003a16c
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..27f23c542db4e
--- /dev/null
+++ b/Runtimes/Supplemental/Observation/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftObservation_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftObservation_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Readme.md b/Runtimes/Supplemental/Readme.md
new file mode 100644
index 0000000000000..693115cf39734
--- /dev/null
+++ b/Runtimes/Supplemental/Readme.md
@@ -0,0 +1,52 @@
+# Swift Supplemental Libraries
+
+The supplemental libraries are all libraries that are not one of the Core or
+overlay libraries. Each supplemental library builds as an independent project.
+
+The supplemental libraries are:
+ - CxxInterop
+ - Differentiation
+ - Distributed
+ - Observation
+ - StringProcessing
+ - Runtime
+ - Synchronization
+
+The top-level Supplemental CMakeLists supplies a super-build pattern for
+configuring and compiling each of the supplemental library projects through a
+single CMake invocation. The `Swift_ENABLE_RUNTIMES` CMake option enables the
+specified supplemental libraries. All libraries configured this way are built
+with the same compilers, against the same sysroot, with the same target triple
+and installed into the same location.
+
+## Super-Build
+
+Configuring each project independently is tedious. The Supplemental directory
+contains a Super-Build CMakeLists that invokes the build of each of the
+supplemental libraries in the appropriate order, simplifying the process of
+building each library.
+
+Important configuration variables:
+ - `Swift_ENABLE_RUNTIMES`: Used to configure which runtime libraries are built.
+
+The super-build forwards the following variables to each sub-project
+unconditionally:
+ - `BUILD_SHARED_LIBS`
+ - `CMAKE_BUILD_TYPE`
+ - `CMAKE_INSTALL_PREFIX`
+ - `CMAKE_COLOR_DIAGNOSTICS`
+ - `CMAKE_C_COMPILER`
+ - `CMAKE_C_COMPILER_TARGET`
+ - `CMAKE_CXX_COMPILER`
+ - `CMAKE_CXX_COMPILER_TARGET`
+ - `CMAKE_Swift_COMPILER`
+ - `CMAKE_Swift_COMPILER_TARGET`
+
+If set, the super-build forwards the following values to each sub-project:
+
+ - `SwiftCore_DIR`: Path to the SwiftCore build directory
+ - `CMAKE_MAKE_PROGRAM`: Path to `ninja`
+
+The super-build is for convenience. If more fine-grained control is desired for
+configuring a specific runtime library, you may configure that library
+independently.
diff --git a/Runtimes/Supplemental/Runtime/CMakeLists.txt b/Runtimes/Supplemental/Runtime/CMakeLists.txt
new file mode 100644
index 0000000000000..099fa4945bea2
--- /dev/null
+++ b/Runtimes/Supplemental/Runtime/CMakeLists.txt
@@ -0,0 +1,174 @@
+cmake_minimum_required(VERSION 3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
+
+if(POLICY CMP0157 AND CMAKE_Swift_COMPILER_USE_OLD_DRIVER)
+  cmake_policy(SET CMP0157 OLD)
+endif()
+
+list(APPEND CMAKE_MODULE_PATH
+  "${CMAKE_SOURCE_DIR}/../cmake/modules"
+  "${CMAKE_SOURCE_DIR}/../../cmake/modules")
+
+include(SwiftProjectVersion)
+project(SwiftRuntime
+  LANGUAGES Swift CXX
+  VERSION ${SWIFT_RUNTIME_VERSION})
+
+if(NOT PROJECT_IS_TOP_LEVEL)
+  message(SEND_ERROR "Swift Runtime must build as a standalone project")
+endif()
+
+include(AsmSupport)
+enable_asm_language()
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
+set(CMAKE_CXX_EXTENSIONS NO)
+set(CMAKE_POSITION_INDEPENDENT_CODE YES)
+
+set(${PROJECT_NAME}_SWIFTC_SOURCE_DIR
+  "${PROJECT_SOURCE_DIR}/../../../"
+  CACHE FILEPATH "Path to the root source directory of the Swift compiler")
+
+# Hook point for vendor-specific extensions to the build system
+# Allowed extension points:
+#   - DefaultSettings.cmake
+#   - Settings.cmake
+set(${PROJECT_NAME}_VENDOR_MODULE_DIR "${CMAKE_SOURCE_DIR}/../cmake/modules/vendor"
+  CACHE FILEPATH "Location for private build system extension")
+
+find_package(SwiftCore REQUIRED)
+find_package(SwiftOverlay REQUIRED)
+#find_package(SwiftDarwin)
+
+include(GNUInstallDirs)
+
+include(AvailabilityMacros)
+include(EmitSwiftInterface)
+include(InstallSwiftInterface)
+include(PlatformInfo)
+include(gyb)
+include(ResourceEmbedding)
+include(CatalystSupport)
+
+option(${PROJECT_NAME}_INSTALL_NESTED_SUBDIR "Install libraries under a platform and architecture subdirectory" ON)
+set(${PROJECT_NAME}_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}>" CACHE STRING "")
+set(${PROJECT_NAME}_INSTALL_SWIFTMODULEDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}>" CACHE STRING "")
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/Settings.cmake" OPTIONAL)
+
+option(${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION "Generate ABI resilient runtime libraries"
+  ${SwiftCore_ENABLE_LIBRARY_EVOLUTION})
+
+option(${PROJECT_NAME}_ENABLE_PRESPECIALIZATION "Enable generic metadata prespecialization"
+  ${SwiftCore_ENABLE_PRESPECIALIZATION})
+
+add_compile_options(
+  $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>
+  $<$<COMPILE_LANGUAGE:Swift>:-nostdlibimport>
+  $<$<COMPILE_LANGUAGE:Swift>:-parse-stdlib>
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-swift-version 5>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enforce-exclusivity=unchecked>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NoncopyableGenerics2>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SuppressedAssociatedTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SE427NoInferenceOnExtension>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NonescapableTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature InoutLifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependenceMutableAccessors>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-disable-upcoming-feature MemberImportVisibility>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-lexical-lifetimes=false>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-ossa-modules>"
+  "$<$<COMPILE_LANGUAGE:Swift>:-warn-implicit-overrides>"
+  "$<$<COMPILE_LANGUAGE:Swift>:-cxx-interoperability-mode=default>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -experimental-spi-only-imports>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
+
+# LNK4049: symbol 'symbol' defined in 'filename.obj' is imported
+# LNK4286: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj'
+# LNK4217: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj' in function 'function'
+#
+# We cannot selectively filter the linker warnings as we do not use the MSVC
+# frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
+# a compromise, treat all linker warnings as errors.
+add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Linux>:LINKER:-z,defs>)
+
+add_library(swiftRuntime
+  Address.swift
+  Backtrace.swift
+  Backtrace+Codable.swift
+  BacktraceFormatter.swift
+  Base64.swift
+  ByteSwapping.swift
+  CachingMemoryReader.swift
+  CompactBacktrace.swift
+  CompactImageMap.swift
+  Compression.swift
+  Context.swift
+  CoreSymbolication.swift
+  Dwarf.swift
+  EightByteBuffer.swift
+  Elf.swift
+  ElfImageCache.swift
+  FramePointerUnwinder.swift
+  Image.swift
+  ImageMap.swift
+  ImageMap+Darwin.swift
+  ImageMap+Linux.swift
+  ImageSource.swift
+  Libc.swift
+  LimitSequence.swift
+  MemoryReader.swift
+  OSReleaseScanner.swift
+  ProcMapsScanner.swift
+  Registers.swift
+  Runtime.swift
+  RichFrame.swift
+  SymbolicatedBacktrace.swift
+  Utils.swift
+  Win32Extras.cpp
+  get-cpu-context.${SWIFT_ASM_EXT})
+
+set_target_properties(swiftRuntime PROPERTIES
+  Swift_MODULE_NAME Runtime)
+target_compile_definitions(swiftRuntime PRIVATE
+  SWIFT_ASM_AVAILABLE)
+target_compile_options(swiftRuntime PRIVATE
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xcc -fmodule-map-file=${CMAKE_CURRENT_SOURCE_DIR}/modules/module.modulemap>")
+# FIXME: We should split out the parts that are needed by the runtime to avoid
+# pulling in headers from the compiler.
+target_include_directories(swiftRuntime PRIVATE
+  "${${PROJECT_NAME}_SWIFTC_SOURCE_DIR}/include")
+target_link_libraries(swiftRuntime PRIVATE
+  swiftShims
+  swiftCore
+  swift_Concurrency
+  swiftCxxStdlib
+  $<$<PLATFORM_ID:Android>:swiftAndroid>
+  #$<$<PLATFORM_ID:Darwin>:swiftDarwin>
+  $<$<PLATFORM_ID:Linux>:swiftGlibc>
+  $<$<PLATFORM_ID:Windows>:swiftWinSDK>)
+
+install(TARGETS swiftRuntime
+  EXPORT SwiftRuntimeTargets
+  COMPONENT ${PROJECT_NAME}_runtime
+  ARCHIVE DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swiftRuntime)
+install_swift_interface(swiftRuntime)
+
+# Configure plist creation for Darwin platforms.
+generate_plist(swiftRuntime "${CMAKE_PROJECT_VERSION}" swiftRuntime)
+embed_manifest(swiftRuntime)
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/SwiftRuntime.cmake" OPTIONAL)
diff --git a/Runtimes/Supplemental/StringProcessing/CMakeLists.txt b/Runtimes/Supplemental/StringProcessing/CMakeLists.txt
index 43d1e7890c208..709ba16918411 100644
--- a/Runtimes/Supplemental/StringProcessing/CMakeLists.txt
+++ b/Runtimes/Supplemental/StringProcessing/CMakeLists.txt
@@ -1,33 +1,74 @@
 cmake_minimum_required(VERSION 3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
 
-set(CMAKE_POSITION_INDEPENDENT_CODE YES)
+if(POLICY CMP0157 AND CMAKE_Swift_COMPILER_USE_OLD_DRIVER)
+  cmake_policy(SET CMP0157 OLD)
+endif()
 
-list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/../cmake/modules")
 
-if($ENV{BUILD_NUMBER})
-  math(EXPR BUILD_NUMBER "$ENV{BUILD_NUMBER} % 65535")
-  set(BUILD_NUMBER ".${BUILD_NUMBER}")
-endif()
+list(APPEND CMAKE_MODULE_PATH
+  "${CMAKE_SOURCE_DIR}/../cmake/modules"
+  "${CMAKE_SOURCE_DIR}/../../cmake/modules")
+
+include(LanguageVersions)
+include(SwiftProjectVersion)
 project(SwiftStringProcessing
   LANGUAGES Swift C
-  VERSION 6.1.0${BUILD_NUMBER})
+  VERSION ${SWIFT_RUNTIME_VERSION})
 
 if(NOT PROJECT_IS_TOP_LEVEL)
   message(FATAL_ERROR "Swift StringProcessing must build as a standalone project")
 endif()
 
+set(CMAKE_POSITION_INDEPENDENT_CODE YES)
+
 set(${PROJECT_NAME}_SWIFTC_SOURCE_DIR
   "${PROJECT_SOURCE_DIR}/../../../"
   CACHE FILEPATH "Path to the root source directory of the Swift compiler")
 
-find_package(SwiftCore)
+find_package(SwiftCore REQUIRED)
+
+include(GNUInstallDirs)
 
 include(AvailabilityMacros)
+include(EmitSwiftInterface)
+include(InstallSwiftInterface)
+include(PlatformInfo)
+include(ResourceEmbedding)
+
+option(${PROJECT_NAME}_INSTALL_NESTED_SUBDIR "Install libraries under a platform and architecture subdirectory" ON)
+set(${PROJECT_NAME}_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${PROJECT_NAME}_INSTALL_NESTED_SUBDIR>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}>")
+set(${PROJECT_NAME}_INSTALL_SWIFTMODULEDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${PROJECT_NAME}_INSTALL_NESTED_SUBDIR>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}>")
+
+option(${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION "Generate ABI resilient runtime libraries"
+  ${SwiftCore_ENABLE_LIBRARY_EVOLUTION})
+
+option(${PROJECT_NAME}_ENABLE_PRESPECIALIZATION "Enable generic metadata prespecialization"
+  ${SwiftCore_ENABLE_PRESPECIALIZATION})
 
 add_compile_options(
   $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>
   $<$<COMPILE_LANGUAGE:Swift>:-nostdlibimport>
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>")
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-concurrency-module-import>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>"
+  "$<$<COMPILE_LANGUAGE:Swift>:-warn-implicit-overrides>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
+
+# LNK4049: symbol 'symbol' defined in 'filename.obj' is imported
+# LNK4286: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj'
+# LNK4217: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj' in function 'function'
+#
+# We cannot selectively filter the linker warnings as we do not use the MSVC
+# frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
+# a compromise, treat all linker warnings as errors.
+add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Android,Linux>:LINKER:-z,defs>)
 
 add_subdirectory(_RegexParser)
 add_subdirectory(_StringProcessing)
diff --git a/Runtimes/Supplemental/StringProcessing/RegexBuilder/CMakeLists.txt b/Runtimes/Supplemental/StringProcessing/RegexBuilder/CMakeLists.txt
index c42a60778f9da..a76f8550d2bf5 100644
--- a/Runtimes/Supplemental/StringProcessing/RegexBuilder/CMakeLists.txt
+++ b/Runtimes/Supplemental/StringProcessing/RegexBuilder/CMakeLists.txt
@@ -13,3 +13,12 @@ target_link_libraries(swiftRegexBuilder PRIVATE
   swift_RegexParser
   swift_StringProcessing
   swiftCore)
+
+install(TARGETS swiftRegexBuilder
+  ARCHIVE DESTINATION "${SwiftStringProcessing_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftStringProcessing_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swiftRegexBuilder)
+install_swift_interface(swiftRegexBuilder)
+
+embed_manifest(swiftRegexBuilder)
diff --git a/Runtimes/Supplemental/StringProcessing/_RegexParser/CMakeLists.txt b/Runtimes/Supplemental/StringProcessing/_RegexParser/CMakeLists.txt
index 0285297831a70..0fed65de6ceb5 100644
--- a/Runtimes/Supplemental/StringProcessing/_RegexParser/CMakeLists.txt
+++ b/Runtimes/Supplemental/StringProcessing/_RegexParser/CMakeLists.txt
@@ -31,7 +31,17 @@ add_library(swift_RegexParser
   Utility/Errors.swift
   Utility/MissingUnicode.swift)
 
-target_link_libraries(swift_RegexParser PRIVATE swiftCore)
+target_link_libraries(swift_RegexParser PRIVATE
+  swiftCore)
 
 set_target_properties(swift_RegexParser PROPERTIES
   Swift_MODULE_NAME _RegexParser)
+
+install(TARGETS swift_RegexParser
+  ARCHIVE DESTINATION "${SwiftStringProcessing_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftStringProcessing_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swift_RegexParser)
+install_swift_interface(swift_RegexParser)
+
+embed_manifest(swift_RegexParser)
diff --git a/Runtimes/Supplemental/StringProcessing/_StringProcessing/CMakeLists.txt b/Runtimes/Supplemental/StringProcessing/_StringProcessing/CMakeLists.txt
index 81b3e408897d9..99a0420852532 100644
--- a/Runtimes/Supplemental/StringProcessing/_StringProcessing/CMakeLists.txt
+++ b/Runtimes/Supplemental/StringProcessing/_StringProcessing/CMakeLists.txt
@@ -78,3 +78,12 @@ set_target_properties(swift_StringProcessing PROPERTIES
 target_link_libraries(swift_StringProcessing PRIVATE
     swift_RegexParser
     swiftCore)
+
+install(TARGETS swift_StringProcessing
+  ARCHIVE DESTINATION "${SwiftStringProcessing_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftStringProcessing_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swift_StringProcessing)
+install_swift_interface(swift_StringProcessing)
+
+embed_manifest(swift_StringProcessing)
diff --git a/Runtimes/Supplemental/Synchronization/CMakeLists.txt b/Runtimes/Supplemental/Synchronization/CMakeLists.txt
new file mode 100644
index 0000000000000..2ab0500c53d94
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/CMakeLists.txt
@@ -0,0 +1,200 @@
+cmake_minimum_required(VERSION 3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
+
+if(POLICY CMP0157 AND CMAKE_Swift_COMPILER_USE_OLD_DRIVER)
+  cmake_policy(SET CMP0157 OLD)
+endif()
+
+list(APPEND CMAKE_MODULE_PATH
+  "${CMAKE_SOURCE_DIR}/../cmake/modules"
+  "${CMAKE_SOURCE_DIR}/../../cmake/modules")
+
+include(LanguageVersions)
+include(SwiftProjectVersion)
+project(SwiftSynchronization
+  LANGUAGES Swift
+  VERSION ${SWIFT_RUNTIME_VERSION})
+
+# FIXME(compnerd) this is a workaround for `GNUInstallDirs` which cannot be used
+# with a pure Swift project.
+enable_language(C)
+
+if(NOT PROJECT_IS_TOP_LEVEL)
+  message(SEND_ERROR "Swift Synchronization must build as a standalone project")
+endif()
+
+set(CMAKE_POSITION_INDEPENDENT_CODE YES)
+
+set(${PROJECT_NAME}_SWIFTC_SOURCE_DIR
+  "${PROJECT_SOURCE_DIR}/../../../"
+  CACHE FILEPATH "Path to the root source directory of the Swift compiler")
+
+# Hook point for vendor-specific extensions to the build system
+# Allowed extension points:
+#   - DefaultSettings.cmake
+#   - Settings.cmake
+set(${PROJECT_NAME}_VENDOR_MODULE_DIR "${CMAKE_SOURCE_DIR}/../cmake/modules/vendor"
+  CACHE FILEPATH "Location for private build system extension")
+
+find_package(SwiftCore REQUIRED)
+find_package(SwiftOverlay)
+
+include(GNUInstallDirs)
+
+include(AvailabilityMacros)
+include(EmitSwiftInterface)
+include(InstallSwiftInterface)
+include(PlatformInfo)
+include(gyb)
+include(ResourceEmbedding)
+include(CatalystSupport)
+
+option(${PROJECT_NAME}_INSTALL_NESTED_SUBDIR "Install libraries under a platform and architecture subdirectory" ON)
+set(${PROJECT_NAME}_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}>" CACHE STRING "")
+set(${PROJECT_NAME}_INSTALL_SWIFTMODULEDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}>" CACHE STRING "")
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/Settings.cmake" OPTIONAL)
+
+option(${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION "Generate ABI resilient runtime libraries"
+  ${SwiftCore_ENABLE_LIBRARY_EVOLUTION})
+
+option(${PROJECT_NAME}_ENABLE_PRESPECIALIZATION "Enable generic metadata prespecialization"
+  ${SwiftCore_ENABLE_PRESPECIALIZATION})
+
+option(${PROJECT_NAME}_SINGLE_THREADED_MODE "Build Synchronization assuming it will be used in an environment with only a single thread" OFF)
+
+add_compile_options(
+  $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>
+  $<$<COMPILE_LANGUAGE:Swift>:-nostdlibimport>
+  $<$<COMPILE_LANGUAGE:Swift>:-enable-builtin-module>
+  $<$<COMPILE_LANGUAGE:Swift>:-strict-memory-safety>
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NoncopyableGenerics2>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SuppressedAssociatedTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature SE427NoInferenceOnExtension>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature NonescapableTypes>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature InoutLifetimeDependence>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature LifetimeDependenceMutableAccessors>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-upcoming-feature MemberImportVisibility>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature RawLayout>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature StaticExclusiveOnly>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Extern>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-runtime-compatibility-version none>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-autolinking-runtime-compatibility-dynamic-replacements>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-autolinking-runtime-compatibility-concurrency>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-concurrency-module-import>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enforce-exclusivity=unchecked>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-lexical-lifetimes=false>"
+  "$<$<COMPILE_LANGUAGE:Swift>:-warn-implicit-overrides>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
+
+# LNK4049: symbol 'symbol' defined in 'filename.obj' is imported
+# LNK4286: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj'
+# LNK4217: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj' in function 'function'
+#
+# We cannot selectively filter the linker warnings as we do not use the MSVC
+# frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
+# a compromise, treat all linker warnings as errors.
+add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Android,Linux>:LINKER:-z,defs>)
+
+gyb_expand(Atomics/AtomicIntegers.swift.gyb Atomics/AtomicIntegers.swift)
+gyb_expand(Atomics/AtomicStorage.swift.gyb Atomics/AtomicStorage.swift)
+
+add_library(swiftSynchronization
+  Atomics/Atomic.swift
+  Atomics/AtomicBool.swift
+  Atomics/AtomicFloats.swift
+  Atomics/AtomicLazyReference.swift
+  Atomics/AtomicMemoryOrderings.swift
+  Atomics/AtomicOptional.swift
+  Atomics/AtomicPointers.swift
+  Atomics/AtomicRepresentable.swift
+  Atomics/WordPair.swift
+  Atomics/AtomicStorage.swift
+  Atomics/AtomicIntegers.swift
+  Cell.swift)
+
+# Determine Mutex definition
+if(${PROJECT_NAME}_SINGLE_THREADED_MODE)
+  target_sources(swiftSynchronization PRIVATE
+    Mutex/MutexUnavailable.swift)
+else()
+  target_sources(swiftSynchronization PRIVATE
+    Mutex/Mutex.swift
+    $<$<PLATFORM_ID:Darwin>:Mutex/DarwinImpl.swift>
+    $<$<PLATFORM_ID:Android,Linux>:Mutex/LinuxImpl.swift>
+    $<$<PLATFORM_ID:Android,WASI>:Mutex/SpinLoopHint.swift>
+    $<$<PLATFORM_ID:Windows>:Mutex/WindowsImpl.swift>)
+endif()
+
+set_target_properties(swiftSynchronization PROPERTIES
+  Swift_MODULE_NAME Synchronization)
+
+target_link_libraries(swiftSynchronization PRIVATE
+  swiftCore
+  $<$<PLATFORM_ID:Android>:swiftAndroid>
+  $<$<PLATFORM_ID:Darwin>:swiftDarwin>
+  $<$<PLATFORM_ID:Windows>:ClangModules>)
+
+if(WIN32 AND CMAKE_SYSTEM_PROCESSOR STREQUAL i686)
+  # FIXME(#83765) `-whole-module-optimization` should not be needed. However,
+  # without this, we will not properly optimize. On Windows i686 in particular,
+  # we observe the formation of `__atomic_load` calls rather than the expected
+  # native sequence.
+  cmake_policy(GET CMP0157 _PolicyCMP0157)
+  if(_PolicyCMP0157 STREQUAL NEW)
+    set_target_properties(swiftSynchronization PROPERTIES
+      Swift_COMPILATION_MODE wholemodule)
+  else()
+    target_compile_options(swiftSynchronization PRIVATE
+      $<$<COMPILE_LANGUAGE:Swift>:-whole-module-optimization>)
+  endif()
+
+  # WMO requires the early-swift-driver to be usable, which is not yet ready on
+  # Windows. Workaround this by creating an empty stub for swiftCore, removing
+  # the import library from the command line, and adding the library search path
+  # associated with it. Due to the autolink, we will still link against the
+  # library from the correct location but will also use an empty file for the
+  # additional input allowing us to perform the WMO.
+  if(CMAKE_Swift_COMPILER_USE_OLD_DRIVER)
+    get_target_property(_swiftCore_IMPORTED_IMPLIB_RELEASE swiftCore
+      IMPORTED_IMPLIB_RELEASE)
+    if(_swiftCore_IMPORTED_IMPLIB_RELEASE)
+      # Compute the library directory to allow us to find the import library by
+      # name.
+      get_filename_component(_swiftCore_IMPORTED_IMPLIB_RELEASE_DIRNAME
+        ${_swiftCore_IMPORTED_IMPLIB_RELEASE} DIRECTORY)
+      # Create a (empty) stub library
+      file(TOUCH "${CMAKE_CURRENT_BINARY_DIR}/swiftCoreStub.lib")
+      # Replace the import library with a stub to bypass the driver and frontend.
+      # Add the library search path to allow linking via autolinking.
+      set_target_properties(swiftCore PROPERTIES
+        IMPORTED_IMPLIB_RELEASE "${CMAKE_CURRENT_BINARY_DIR}/swiftCoreStub.lib"
+        INTERFACE_LINK_DIRECTORIES ${_swiftCore_IMPORTED_IMPLIB_RELEASE_DIRNAME})
+    endif()
+  endif()
+endif()
+
+install(TARGETS swiftSynchronization
+  EXPORT SwiftSynchronizationTargets
+  COMPONENT ${PROJECT_NAME}_runtime
+  ARCHIVE DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swiftSynchronization)
+install_swift_interface(swiftSynchronization)
+
+# Configure plist creation for Darwin platforms.
+generate_plist(swiftSynchronization "${CMAKE_PROJECT_VERSION}" swiftSynchronization)
+embed_manifest(swiftSynchronization)
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/swiftSynchronization.cmake" OPTIONAL)
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/apple-common.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/apple-common.cmake
new file mode 100644
index 0000000000000..045a720d448c1
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/apple-common.cmake
@@ -0,0 +1,7 @@
+set(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+set(BUILD_SHARED_LIBS YES CACHE BOOL "")
+set(SwiftSynchronization_INSTALL_NESTED_SUBDIR OFF CACHE BOOL "")
+
+set(CMAKE_CXX_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_C_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_Swift_FLAGS_MINSIZEREL "-Osize -g" CACHE STRING "")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..4ddb5b22db83d
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
new file mode 100644
index 0000000000000..767b7fb22d150
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
new file mode 100644
index 0000000000000..4f8d5724c2fe3
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
@@ -0,0 +1,14 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR freestanding CACHE STRING "")
+set(CMAKE_BUILD_TYPE MinSizeRel CACHE STRING "")
+set(SwiftSynchronization_SINGLE_THREADED_MODE YES CACHE BOOL "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
new file mode 100644
index 0000000000000..22e345648bd07
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftSynchronization_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftSynchronization_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftSynchronization_COMPILER_VARIANT_TARGET "arm64-apple-ios${SwiftSynchronization_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..f9856d3590382
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..e0c728b134474
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..827858a5faea2
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
new file mode 100644
index 0000000000000..2b5e04dac0611
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
new file mode 100644
index 0000000000000..f50e5881a1fc5
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64_32 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
new file mode 100644
index 0000000000000..4cb83abac73b4
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
new file mode 100644
index 0000000000000..fc55849dde75e
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftSynchronization_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftSynchronization_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftSynchronization_COMPILER_VARIANT_TARGET "arm64e-apple-ios${SwiftSynchronization_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
new file mode 100644
index 0000000000000..ee82d8970b384
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-XROS.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
new file mode 100644
index 0000000000000..bd57c6bafe351
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR xros CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
new file mode 100644
index 0000000000000..93dac83fdf3b3
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..5219f6e6e7571
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
new file mode 100644
index 0000000000000..8f0e265e9a99b
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftSynchronization_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftSynchronization_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftSynchronization_COMPILER_VARIANT_TARGET "x86_64-apple-ios${SwiftSynchronization_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..3c79d9826a06b
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..23f9cdcbc67e4
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..8758aa157c97f
--- /dev/null
+++ b/Runtimes/Supplemental/Synchronization/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftSynchronization_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftSynchronization_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/CMakeLists.txt b/Runtimes/Supplemental/Volatile/CMakeLists.txt
new file mode 100644
index 0000000000000..ad8fc2428852a
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/CMakeLists.txt
@@ -0,0 +1,106 @@
+cmake_minimum_required(VERSION 3.29)
+# TODO before requiring CMake 4.1 or later
+# and/or enforcing CMP0195, please check/update
+# the implementation  of `emit_swift_interface`
+# in `EmitSwiftInterface.cmake`
+# to ensure it keeps laying down nested swiftmodule folders
+
+if(POLICY CMP0157 AND CMAKE_Swift_COMPILER_USE_OLD_DRIVER)
+  cmake_policy(SET CMP0157 OLD)
+endif()
+
+list(APPEND CMAKE_MODULE_PATH
+  "${CMAKE_SOURCE_DIR}/../cmake/modules"
+  "${CMAKE_SOURCE_DIR}/../../cmake/modules")
+
+include(LanguageVersions)
+include(SwiftProjectVersion)
+project(SwiftVolatile
+  LANGUAGES Swift
+  VERSION ${SWIFT_RUNTIME_VERSION})
+
+# FIXME(compnerd) this is a workaround for `GNUInstallDirs` which cannot be used
+# with a pure Swift project.
+enable_language(C)
+
+if(NOT PROJECT_IS_TOP_LEVEL)
+  message(SEND_ERROR "Swift Observation must build as a standalone project")
+endif()
+
+set(${PROJECT_NAME}_SWIFTC_SOURCE_DIR
+  "${PROJECT_SOURCE_DIR}/../../../"
+  CACHE FILEPATH "Path to the root source directory of the Swift compiler")
+
+# Hook point for vendor-specific extensions to the build system
+# Allowed extension points:
+#   - DefaultSettings.cmake
+#   - Settings.cmake
+set(${PROJECT_NAME}_VENDOR_MODULE_DIR "${CMAKE_SOURCE_DIR}/../cmake/modules/vendor"
+  CACHE FILEPATH "Location for private build system extension")
+
+find_package(SwiftCore REQUIRED)
+find_package(SwiftOverlay REQUIRED)
+
+include(GNUInstallDirs)
+
+include(AvailabilityMacros)
+include(EmitSwiftInterface)
+include(InstallSwiftInterface)
+include(PlatformInfo)
+include(gyb)
+include(ResourceEmbedding)
+include(CatalystSupport)
+
+option(${PROJECT_NAME}_INSTALL_NESTED_SUBDIR "Install libraries under a platform and architecture subdirectory" ON)
+set(${PROJECT_NAME}_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}>" CACHE STRING "")
+set(${PROJECT_NAME}_INSTALL_SWIFTMODULEDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>$<$<BOOL:${${PROJECT_NAME}_INSTALL_NESTED_SUBDIR}>:/${${PROJECT_NAME}_PLATFORM_SUBDIR}>" CACHE STRING "")
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/Settings.cmake" OPTIONAL)
+
+option(${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION "Generate ABI resilient runtime libraries"
+  ${SwiftCore_ENABLE_LIBRARY_EVOLUTION})
+
+option(${PROJECT_NAME}_ENABLE_PRESPECIALIZATION "Enable generic metadata prespecialization"
+  ${SwiftCore_ENABLE_PRESPECIALIZATION})
+
+add_compile_options(
+  $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>
+  $<$<COMPILE_LANGUAGE:Swift>:-nostdlibimport>
+  $<$<COMPILE_LANGUAGE:Swift>:-strict-memory-safety>
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
+  "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
+
+# LNK4049: symbol 'symbol' defined in 'filename.obj' is imported
+# LNK4286: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj'
+# LNK4217: symbol 'symbol' defined in 'filename_1.obj' is imported by 'filename_2.obj' in function 'function'
+#
+# We cannot selectively filter the linker warnings as we do not use the MSVC
+# frontend and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
+# a compromise, treat all linker warnings as errors.
+add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Android,Linux>:LINKER:-z,defs>)
+
+add_library(swift_Volatile
+  Volatile.swift)
+set_target_properties(swift_Volatile PROPERTIES
+  Swift_MODULE_NAME _Volatile)
+target_compile_options(swift_Volatile PRIVATE
+  -parse-stdlib)
+target_link_libraries(swift_Volatile PRIVATE
+  swiftCore)
+
+install(TARGETS swift_Volatile
+  EXPORT SwiftVolatileTargets
+  COMPONENT ${PROJECT_NAME}_runtime
+  ARCHIVE DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${${PROJECT_NAME}_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swift_Volatile)
+install_swift_interface(swift_Volatile)
+
+# Configure plist creation for Darwin platforms.
+generate_plist(swift_Volatile "${CMAKE_PROJECT_VERSION}" swift_Volatile)
+embed_manifest(swift_Volatile)
+
+include("${${PROJECT_NAME}_VENDOR_MODULE_DIR}/swift_Volatile.cmake" OPTIONAL)
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/apple-common.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/apple-common.cmake
new file mode 100644
index 0000000000000..8fdc66eddff83
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/apple-common.cmake
@@ -0,0 +1,7 @@
+set(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+set(BUILD_SHARED_LIBS YES CACHE BOOL "")
+set(SwiftVolatile_INSTALL_NESTED_SUBDIR OFF CACHE BOOL "")
+
+set(CMAKE_CXX_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_C_FLAGS_MINSIZEREL "-Os -g -DNDEBUG" CACHE STRING "")
+set(CMAKE_Swift_FLAGS_MINSIZEREL "-Osize -g" CACHE STRING "")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..8771cb9bf5fe6
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
new file mode 100644
index 0000000000000..d83851da81a44
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
new file mode 100644
index 0000000000000..cb2e76889149a
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-BridgeOS.cmake
@@ -0,0 +1,14 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-bridgeos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR freestanding CACHE STRING "")
+set(CMAKE_BUILD_TYPE MinSizeRel CACHE STRING "")
+set(SwiftVolatile_SINGLE_THREADED_MODE YES CACHE BOOL "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
new file mode 100644
index 0000000000000..7ea72c039372d
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftVolatile_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftVolatile_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftVolatile_COMPILER_VARIANT_TARGET "arm64-apple-ios${SwiftVolatile_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..1471461a4c007
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..8a4a6ab9d9fc4
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..519dc9f6c83ab
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
new file mode 100644
index 0000000000000..651f8f38df426
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
new file mode 100644
index 0000000000000..6cda9a5a0fa61
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64_32-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64_32-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64_32 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
new file mode 100644
index 0000000000000..32da678fcf0de
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-AppleTVOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR appletvos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
new file mode 100644
index 0000000000000..f5439313dcf3e
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftVolatile_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftVolatile_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftVolatile_COMPILER_VARIANT_TARGET "arm64e-apple-ios${SwiftVolatile_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
new file mode 100644
index 0000000000000..defa080f4c3cc
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-WatchOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR watchos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-XROS.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
new file mode 100644
index 0000000000000..83eb8c7a43670
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-XROS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR xros CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
new file mode 100644
index 0000000000000..424a69d44353e
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/arm64e-iPhoneOS.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "arm64e-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR arm64e CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR iphoneos CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
new file mode 100644
index 0000000000000..88e8ee6f9e664
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-AppleTVOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-tvos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR appletvsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
new file mode 100644
index 0000000000000..b7f9c77ef530a
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-MacOSX.cmake
@@ -0,0 +1,18 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+if(NOT DEFINED SwiftVolatile_TARGET_VARIANT_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "SwiftVolatile_TARGET_VARIANT_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR macosx CACHE STRING "")
+
+set(SwiftVolatile_COMPILER_VARIANT_TARGET "x86_64-apple-ios${SwiftVolatile_TARGET_VARIANT_DEPLOYMENT_TARGET}-macabi" CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
new file mode 100644
index 0000000000000..65e3ae6791e05
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-WatchOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-watchos${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR watchsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
new file mode 100644
index 0000000000000..4f1ab9dc83d17
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-XROS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-xros${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR xrsimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
new file mode 100644
index 0000000000000..e17145f1df1ad
--- /dev/null
+++ b/Runtimes/Supplemental/Volatile/cmake/caches/Vendors/Apple/x86_64-iPhoneOS-simulator.cmake
@@ -0,0 +1,12 @@
+if(NOT DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+  message(SEND_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET not defined")
+endif()
+
+set(CMAKE_C_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_CXX_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+set(CMAKE_Swift_COMPILER_TARGET "x86_64-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}-simulator" CACHE STRING "")
+
+set(SwiftVolatile_ARCH_SUBDIR x86_64 CACHE STRING "")
+set(SwiftVolatile_PLATFORM_SUBDIR iphonesimulator CACHE STRING "")
+
+include("${CMAKE_CURRENT_LIST_DIR}/apple-common.cmake")
diff --git a/Runtimes/Supplemental/cmake/modules/AsmSupport.cmake b/Runtimes/Supplemental/cmake/modules/AsmSupport.cmake
new file mode 100644
index 0000000000000..b957afb6d2dd8
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/AsmSupport.cmake
@@ -0,0 +1,15 @@
+macro(enable_asm_language)
+  # On Windows, use MASM or MARMASM
+  set(SWIFT_ASM_DIALECT ASM)
+  set(SWIFT_ASM_EXT S)
+  if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
+    if(CMAKE_SYSTEM_PROCESSOR MATCHES "ARM64")
+      set(SWIFT_ASM_DIALECT ASM_MARMASM)
+    else()
+      set(SWIFT_ASM_DIALECT ASM_MASM)
+    endif()
+    set(SWIFT_ASM_EXT asm)
+  endif()
+
+  enable_language(${SWIFT_ASM_DIALECT})
+endmacro()
diff --git a/Runtimes/Supplemental/cmake/modules/CatalystSupport.cmake b/Runtimes/Supplemental/cmake/modules/CatalystSupport.cmake
new file mode 100644
index 0000000000000..69c341a1d58e6
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/CatalystSupport.cmake
@@ -0,0 +1,48 @@
+include(CheckCompilerFlag)
+
+# Add flags for generating the zippered target variant in the build
+
+# Initialize `${PROJECT_NAME}_VARIANT_MODULE_TRIPLE` if the driver is able to emit
+# modules for the target variant.
+
+if(${PROJECT_NAME}_COMPILER_VARIANT_TARGET)
+  add_compile_options(
+    "$<$<COMPILE_LANGUAGE:C,CXX>:SHELL:-darwin-target-variant ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>"
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-target-variant ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>"
+
+    # TODO: Remove me once we have a driver with
+    #   https://github.com/swiftlang/swift-driver/pull/1803
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xclang-linker -darwin-target-variant -Xclang-linker ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>")
+
+  add_link_options(
+    "$<$<LINK_LANGUAGE:C,CXX>:SHELL:-darwin-target-variant ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>"
+    "$<$<LINK_LANGUAGE:Swift>:SHELL:-target-variant ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>"
+
+    # TODO: Remove me once we have a driver with
+    #   https://github.com/swiftlang/swift-driver/pull/1803
+    "$<$<LINK_LANGUAGE:Swift>:SHELL:-Xclang-linker -darwin-target-variant -Xclang-linker ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET}>")
+
+  # TODO: Once we are guaranteed to have a driver with the variant module path
+  #       support everywhere, we should integrate this into PlatformInfo.cmake
+  check_compiler_flag(Swift "-emit-variant-module-path ${CMAKE_CURRENT_BINARY_DIR}/CompilerID/variant.swiftmodule" HAVE_Swift_VARIANT_MODULE_PATH_FLAG)
+  if(HAVE_Swift_VARIANT_MODULE_PATH_FLAG)
+    # Get variant module triple
+    set(module_triple_command "${CMAKE_Swift_COMPILER}" -print-target-info -target ${${PROJECT_NAME}_COMPILER_VARIANT_TARGET})
+    execute_process(COMMAND ${module_triple_command} OUTPUT_VARIABLE target_info_json)
+    message(CONFIGURE_LOG "Swift target variant info: ${target_info_json}")
+
+
+    string(JSON module_triple GET "${target_info_json}" "target" "moduleTriple")
+    set(${PROJECT_NAME}_VARIANT_MODULE_TRIPLE "${module_triple}" CACHE STRING "Triple used for installed swift{module,interface} files for the target variant")
+    mark_as_advanced(${PROJECT_NAME}_VARIANT_MODULE_TRIPLE)
+    message(CONFIGURE_LOG "Swift target variant module triple: ${module_triple}")
+  endif()
+
+  if(${PROJECT_NAME}_EXPERIMENTAL_EMIT_VARIANT_MODULE)
+    check_compiler_flag(Swift "-experimental-emit-variant-module" HAVE_Swift_EMIT_VARIANT_MODULE_FLAG)
+    if(HAVE_Swift_EMIT_VARIANT_MODULE_FLAG)
+    add_compile_options(
+        "$<$<COMPILE_LANGUAGE:Swift>:-experimental-emit-variant-module>")
+    endif()
+  endif()
+endif()
diff --git a/Runtimes/Supplemental/cmake/modules/EmitSwiftInterface.cmake b/Runtimes/Supplemental/cmake/modules/EmitSwiftInterface.cmake
new file mode 100644
index 0000000000000..8a3540dd55e07
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/EmitSwiftInterface.cmake
@@ -0,0 +1,54 @@
+# Generate and install swift interface files
+
+# TODO: CMake should learn how to model library evolution and generate this
+#       stuff automatically.
+
+
+# Generate a swift interface file for the target if library evolution is enabled
+function(emit_swift_interface target)
+  # Generate the target-variant binary swift module when performing zippered
+  # build
+  # Clean this up once CMake has nested swiftmodules in the build directory:
+  # https://gitlab.kitware.com/cmake/cmake/-/merge_requests/10664
+  # https://cmake.org/cmake/help/git-stage/policy/CMP0195.html
+
+  # We can't expand the Swift_MODULE_NAME target property in a generator
+  # expression or it will fail saying that the target doesn't exist.
+  get_target_property(module_name ${target} Swift_MODULE_NAME)
+  if(NOT module_name)
+    set(module_name ${target})
+  endif()
+  # Account for an existing swiftmodule file
+  # generated with the previous logic
+  if(EXISTS "${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule"
+     AND NOT IS_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule")
+    message(STATUS "Removing regular file ${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule to support nested swiftmodule generation")
+    file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule")
+  endif()
+  target_compile_options(${target} PRIVATE
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-module-path ${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule/${${PROJECT_NAME}_MODULE_TRIPLE}.swiftmodule>")
+  if(${PROJECT_NAME}_VARIANT_MODULE_TRIPLE)
+    target_compile_options(${target} PRIVATE
+      "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-path ${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule/${${PROJECT_NAME}_VARIANT_MODULE_TRIPLE}.swiftmodule>")
+  endif()
+  add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule/${${PROJECT_NAME}_MODULE_TRIPLE}.swiftmodule"
+    DEPENDS ${target})
+  target_sources(${target}
+    INTERFACE
+      $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule/${${PROJECT_NAME}_MODULE_TRIPLE}.swiftmodule>)
+
+  # Generate textual swift interfaces is library-evolution is enabled
+  if(${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION)
+    target_compile_options(${target} PRIVATE
+      $<$<COMPILE_LANGUAGE:Swift>:-emit-module-interface-path$<SEMICOLON>${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule/${${PROJECT_NAME}_MODULE_TRIPLE}.swiftinterface>
+      $<$<COMPILE_LANGUAGE:Swift>:-emit-private-module-interface-path$<SEMICOLON>${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule/${${PROJECT_NAME}_MODULE_TRIPLE}.private.swiftinterface>)
+    if(${PROJECT_NAME}_VARIANT_MODULE_TRIPLE)
+      target_compile_options(${target} PRIVATE
+        "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-module-interface-path ${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule/${${PROJECT_NAME}_VARIANT_MODULE_TRIPLE}.swiftinterface>"
+        "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-emit-variant-private-module-interface-path ${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule/${${PROJECT_NAME}_VARIANT_MODULE_TRIPLE}.private.swiftinterface>")
+    endif()
+    target_compile_options(${target} PRIVATE
+      $<$<COMPILE_LANGUAGE:Swift>:-library-level$<SEMICOLON>api>
+      $<$<COMPILE_LANGUAGE:Swift>:-Xfrontend$<SEMICOLON>-require-explicit-availability=ignore>)
+  endif()
+endfunction()
diff --git a/Runtimes/Supplemental/cmake/modules/FindSwiftCore.cmake b/Runtimes/Supplemental/cmake/modules/FindSwiftCore.cmake
new file mode 100644
index 0000000000000..98bfd4c6b6de3
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/FindSwiftCore.cmake
@@ -0,0 +1,304 @@
+#[=======================================================================[.rst:
+FindSwiftCore
+------------
+
+Find SwiftCore, deferring to SwiftCoreConfig.cmake when requested.
+This is meant to find the core library to be linked by the Supplemental libraries.
+
+Imported Targets
+^^^^^^^^^^^^^^^^
+
+The following :prop_tgt:`IMPORTED` TARGETS may be defined:
+
+ ``swiftCore``
+
+Hint Variables
+^^^^^^^^^^^^^^
+
+ ``SDKROOT`` (environment variable)
+   Set the path to the Swift SDK Root.
+   This only affects Windows builds.
+
+ ``Swift_SDKROOT``
+   Set the path to the Swift SDK installation.
+   This only affects Linux and Windows builds.
+   Apple builds always use the library provided by the SDK.
+
+ ``SwiftCore_USE_STATIC_LIBS``
+   Set to boolean true to find static libraries. If not
+   set explicitly this is inferred from the value of
+   `BUILD_SHARED_LIBS` and the current platform.
+
+ ``SwiftCore_INCLUDE_DIR_HINTS``
+   Additional paths to search the swiftmodules into. These
+   are prepended to the ones searched by this find module
+
+ ``SwiftCore_LIBRARY_HINTS``
+   Additional paths to search the libraries into. These
+   are prepended to the ones searched by this find module
+
+ ``SwiftShims_INCLUDE_DIR_HINTS``
+   Additional paths to search the shims into. These
+   are prepended to the ones searched by this find module
+
+ ``SwiftCore_NAMES``
+   Additional names for the Core library
+
+ ``SwiftOnoneSupport_NAMES``
+   Additional names for the SwiftOnoneSupport library
+
+ ``SwiftConcurrency_NAMES``
+   Additional names for the Swift_Concurrency library
+
+Result targets
+^^^^^^^^^^^^^^
+
+If no error is generated, the following targets are available to the users
+
+  * ``swiftCore``
+  * ``swiftSwiftOnoneSupport``
+  * ``swift_Concurrency``
+  * ``swiftShims``
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+The module may set the following variables if `SwiftCore_DIR` is not set.
+(although we suggest relying on the targets above instead)
+
+ ``SwiftCore_FOUND``
+   true if core was found
+
+ ``SwiftCore_INCLUDE_DIR``
+   the directory containing the Swift.swiftmodule folder
+
+ ``SwiftCore_LIBRARY``
+   path to the swiftCore library
+
+ ``SwiftOnoneSupport_INCLUDE_DIR``
+   the directory containing the SwiftOnoneSupport.swiftmodule folder
+
+ ``SwiftOnoneSupport_LIBRARY``
+   path to the SwiftOnoneSupport library
+
+ ``SwiftConcurrency_INCLUDE_DIR``
+   the directory containing the _Concurrency.swiftmodule folder
+
+ ``SwiftConcurrency_LIBRARY``
+   path to the swift_Concurrency library
+
+ ``SwiftShims_INCLUDE_DIR``
+   the directory containing the Swift shims directory
+   (i.e. .../usr/lib/swift, not .../usr/lib/swift/shims)
+
+#]=======================================================================]
+
+include_guard(GLOBAL)
+
+# If the SwiftCore_DIR_FLAG is specified, look there instead. The cmake-generated
+# config file is more accurate, but requires that the SDK has one available.
+if(SwiftCore_DIR)
+  if(SwiftCore_FIND_REQUIRED)
+    list(APPEND args REQUIRED)
+  endif()
+  if(SwiftCore_FIND_QUIETLY)
+    list(APPEND args QUIET)
+  endif()
+  find_package(SwiftCore NO_MODULE ${args})
+  return()
+endif()
+
+include(FindPackageHandleStandardArgs)
+include(PlatformInfo)
+
+# This was loosely modelled after other find modules
+# (namely FindGLEW), where the equivalent parameter
+# is not stored in cache (possibly because we want
+# the project importing it to be able to
+# it "immediately")
+if(NOT DEFINED SwiftCore_USE_STATIC_LIBS)
+  set(SwiftCore_USE_STATIC_LIBS OFF)
+  if(NOT BUILD_SHARED_LIBS AND NOT APPLE)
+    set(SwiftCore_USE_STATIC_LIBS ON)
+  endif()
+endif()
+
+if(APPLE)
+  list(APPEND SwiftCore_INCLUDE_DIR_HINTS
+    "${CMAKE_OSX_SYSROOT}/usr/lib/swift")
+  list(APPEND SwiftCore_LIBRARY_HINTS
+    "${CMAKE_OSX_SYSROOT}/usr/lib/swift")
+  list(APPEND SwiftShims_INCLUDE_DIR_HINTS
+    "${CMAKE_OSX_SYSROOT}/usr/lib/swift")
+  # When building for Apple platforms, SwiftCore always comes from within the
+  # SDK as a tbd for a shared library in the shared cache.
+  list(APPEND SwiftCore_NAMES libswiftCore.tbd)
+  list(APPEND SwiftOnoneSupport_NAMES libswiftSwiftOnoneSupport.tbd)
+  list(APPEND SwiftConcurrency_NAMES libswift_Concurrency.tbd)
+elseif(LINUX)
+  if (SwiftCore_USE_STATIC_LIBS)
+    list(APPEND SwiftCore_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/linux-static")
+    list(APPEND SwiftCore_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/linux-static")
+    list(APPEND SwiftShims_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static"
+      "${Swift_SDKROOT}/usr/lib/swift")
+    list(APPEND SwiftCore_NAMES libswiftCore.a)
+    list(APPEND SwiftOnoneSupport_NAMES libswiftSwiftOnoneSupport.a)
+    list(APPEND SwiftConcurrency_NAMES libswift_Concurrency.a)
+  else()
+    list(APPEND SwiftCore_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/linux")
+    list(APPEND SwiftCore_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/linux")
+    list(APPEND SwiftShims_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift")
+    list(APPEND SwiftCore_NAMES libswiftCore.so)
+    list(APPEND SwiftOnoneSupport_NAMES libswiftSwiftOnoneSupport.so)
+    list(APPEND SwiftConcurrency_NAMES libswift_Concurrency.so)
+  endif()
+elseif(WIN32)
+  list(APPEND SwiftCore_INCLUDE_DIR_HINTS
+    "${Swift_SDKROOT}/usr/lib/swift/windows"
+    "$ENV{SDKROOT}/usr/lib/swift/windows")
+  list(APPEND SwiftCore_LIBRARY_HINTS
+    "${Swift_SDKROOT}/usr/lib/swift/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}"
+    "${Swift_SDKROOT}/usr/lib/swift"
+    "$ENV{SDKROOT}/usr/lib/swift/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}"
+    "$ENV{SDKROOT}/usr/lib/swift")
+  list(APPEND SwiftShims_INCLUDE_DIR_HINTS
+    "${Swift_SDKROOT}/usr/lib/swift"
+    "$ENV{SDKROOT}/usr/lib/swift")
+  if (SwiftCore_USE_STATIC_LIBS)
+    list(APPEND SwiftCore_NAMES libswiftCore.lib)
+    list(APPEND SwiftOnoneSupport_NAMES libswiftSwiftOnoneSupport.lib)
+    list(APPEND SwiftConcurrency_NAMES libswift_Concurrency.lib)
+  else()
+    list(APPEND SwiftCore_NAMES swiftCore.lib)
+    list(APPEND SwiftOnoneSupport_NAMES swiftSwiftOnoneSupport.lib)
+    list(APPEND SwiftConcurrency_NAMES swift_Concurrency.lib)
+  endif()
+elseif(ANDROID)
+  if (SwiftCore_USE_STATIC_LIBS)
+    list(APPEND SwiftCore_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/android"
+      "$ENV{SDKROOT}/usr/lib/swift_static/android")
+    list(APPEND SwiftCore_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "${Swift_SDKROOT}/usr/lib/swift_static"
+      "$ENV{SDKROOT}/usr/lib/swift_static/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "$ENV{SDKROOT}/usr/lib/swift_static")
+    list(APPEND SwiftShims_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static")
+    list(APPEND SwiftCore_NAMES libswiftCore.a)
+    list(APPEND SwiftOnoneSupport_NAMES libswiftSwiftOnoneSupport.a)
+    list(APPEND SwiftConcurrency_NAMES libswift_Concurrency.a)
+  else()
+    list(APPEND SwiftCore_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/android"
+      "$ENV{SDKROOT}/usr/lib/swift/android")
+    list(APPEND SwiftCore_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "${Swift_SDKROOT}/usr/lib/swift"
+      "$ENV{SDKROOT}/usr/lib/swift/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "$ENV{SDKROOT}/usr/lib/swift")
+    list(APPEND SwiftShims_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift")
+    list(APPEND SwiftCore_NAMES libswiftCore.so)
+    list(APPEND SwiftOnoneSupport_NAMES libswiftSwiftOnoneSupport.so)
+    list(APPEND SwiftConcurrency_NAMES libswift_Concurrency.so)
+  endif()
+else()
+  message(FATAL_ERROR "FindSwiftCore.cmake module search not implemented for targeted platform\n"
+  " Build Core for your platform and set `SwiftCore_DIR` to"
+  " the directory containing SwiftCoreConfig.cmake\n")
+endif()
+
+find_path(SwiftCore_INCLUDE_DIR
+  "Swift.swiftmodule"
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${SwiftCore_INCLUDE_DIR_HINTS})
+find_library(SwiftCore_LIBRARY
+  NAMES
+    ${SwiftCore_NAMES}
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${SwiftCore_LIBRARY_HINTS})
+
+find_path(SwiftOnoneSupport_INCLUDE_DIR
+  "SwiftOnoneSupport.swiftmodule"
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${SwiftCore_INCLUDE_DIR_HINTS})
+find_library(SwiftOnoneSupport_LIBRARY
+  NAMES
+    ${SwiftOnoneSupport_NAMES}
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${SwiftCore_LIBRARY_HINTS})
+
+find_path(SwiftConcurrency_INCLUDE_DIR
+  "_Concurrency.swiftmodule"
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${SwiftCore_INCLUDE_DIR_HINTS})
+find_library(SwiftConcurrency_LIBRARY
+  NAMES
+    ${SwiftConcurrency_NAMES}
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${SwiftCore_LIBRARY_HINTS})
+
+if(SwiftCore_USE_STATIC_LIBS)
+  add_library(swiftCore STATIC IMPORTED GLOBAL)
+  add_library(swiftSwiftOnoneSupport STATIC IMPORTED GLOBAL)
+  add_library(swift_Concurrency STATIC IMPORTED GLOBAL)
+else()
+  add_library(swiftCore SHARED IMPORTED GLOBAL)
+  add_library(swiftSwiftOnoneSupport SHARED IMPORTED GLOBAL)
+  add_library(swift_Concurrency SHARED IMPORTED GLOBAL)
+endif()
+
+set_target_properties(swiftCore PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES "${SwiftCore_INCLUDE_DIR}")
+set_target_properties(swiftSwiftOnoneSupport PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES "${SwiftOnoneSupport_INCLUDE_DIR}")
+set_target_properties(swift_Concurrency PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES "${SwiftConcurrency_INCLUDE_DIR}")
+
+if(LINUX OR ANDROID)
+  set_target_properties(swiftCore PROPERTIES
+    IMPORTED_LOCATION "${SwiftCore_LIBRARY}")
+  set_target_properties(swiftSwiftOnoneSupport PROPERTIES
+    IMPORTED_LOCATION "${SwiftOnoneSupport_LIBRARY}")
+  set_target_properties(swift_Concurrency PROPERTIES
+    IMPORTED_LOCATION "${SwiftConcurrency_LIBRARY}")
+else()
+  set_target_properties(swiftCore PROPERTIES
+    IMPORTED_IMPLIB "${SwiftCore_LIBRARY}")
+  set_target_properties(swiftSwiftOnoneSupport PROPERTIES
+    IMPORTED_IMPLIB "${SwiftOnoneSupport_LIBRARY}")
+  set_target_properties(swift_Concurrency PROPERTIES
+    IMPORTED_IMPLIB "${SwiftConcurrency_LIBRARY}")
+endif()
+
+find_path(SwiftShims_INCLUDE_DIR "shims/module.modulemap" HINTS
+  ${SwiftShims_INCLUDE_DIR_HINTS})
+add_library(swiftShims INTERFACE IMPORTED GLOBAL)
+target_include_directories(swiftShims INTERFACE
+# This is needed for targets that import headers from
+# include/swift (e.g. include/swift/ABI/HeapObject.h)
+# that assumes the shims are located in `swift/shims`
+# relative path
+  "${SwiftShims_INCLUDE_DIR}/.."
+  "${SwiftShims_INCLUDE_DIR}/shims")
+target_compile_options(swiftShims INTERFACE
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xcc -fmodule-map-file=\"${SwiftShims_INCLUDE_DIR}/shims/module.modulemap\">")
+
+find_package_handle_standard_args(SwiftCore DEFAULT_MSG
+  SwiftCore_LIBRARY SwiftCore_INCLUDE_DIR
+  SwiftShims_INCLUDE_DIR
+  SwiftOnoneSupport_LIBRARY SwiftOnoneSupport_INCLUDE_DIR
+  SwiftConcurrency_LIBRARY SwiftConcurrency_INCLUDE_DIR)
diff --git a/Runtimes/Supplemental/cmake/modules/FindSwiftDarwin.cmake b/Runtimes/Supplemental/cmake/modules/FindSwiftDarwin.cmake
new file mode 100644
index 0000000000000..ca0bfbff0e6a6
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/FindSwiftDarwin.cmake
@@ -0,0 +1,70 @@
+#[=======================================================================[.rst:
+FindSwiftDarwin
+------------
+
+Find swiftDarwin in the underlying SDK (the only way we obtain such overlay).
+
+Imported Targets
+^^^^^^^^^^^^^^^^
+
+The following :prop_tgt:`IMPORTED` TARGETS may be defined:
+
+ ``swiftDarwin``
+
+#]=======================================================================]
+
+include_guard(GLOBAL)
+
+# This was loosely modelled after other find modules
+# (namely FindGLEW), where the equivalent parameter
+# is not stored in cache (possibly because we want
+# the project importing it to be able to use
+# it "immediately")
+if(NOT DEFINED SwiftDarwin_USE_STATIC_LIBS)
+  set(SwiftDarwin_USE_STATIC_LIBS OFF)
+endif()
+
+include(FindPackageHandleStandardArgs)
+include(PlatformInfo)
+
+if(NOT APPLE)
+  message(WARNING "Darwin is only produced on Apple platforms, so not attempting to search it here.")
+  return()
+endif()
+
+# Look in the SDK
+list(APPEND swiftDarwin_INCLUDE_DIR_HINTS
+  "${CMAKE_OSX_SYSROOT}/usr/lib/swift")
+list(APPEND swiftDarwin_LIBRARY_HINTS
+  "${CMAKE_OSX_SYSROOT}/usr/lib/swift")
+# When building for Apple platforms, swiftDarwin always comes from within the
+# SDK as a tbd for a shared library in the shared cache.
+list(APPEND swiftDarwin_NAMES libswiftDarwin.tbd)
+set(swiftDarwin_MODULE_NAME "Darwin.swiftmodule")
+
+find_path(swiftDarwin_INCLUDE_DIR
+  ${swiftDarwin_MODULE_NAME}
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${swiftDarwin_INCLUDE_DIR_HINTS})
+find_library(swiftDarwin_LIBRARY
+  NAMES
+    ${swiftDarwin_NAMES}
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${swiftDarwin_LIBRARY_HINTS})
+
+if(SwiftDarwin_USE_STATIC_LIBS)
+  add_library(swiftDarwin STATIC IMPORTED GLOBAL)
+else()
+  add_library(swiftDarwin SHARED IMPORTED GLOBAL)
+endif()
+
+target_include_directories(swiftDarwin INTERFACE
+  "${swiftDarwin_INCLUDE_DIR}")
+
+set_target_properties(swiftDarwin PROPERTIES
+  IMPORTED_IMPLIB "${swiftDarwin_LIBRARY}")
+
+find_package_handle_standard_args(SwiftDarwin DEFAULT_MSG
+  "swiftDarwin_LIBRARY" "swiftDarwin_INCLUDE_DIR")
diff --git a/Runtimes/Supplemental/cmake/modules/FindSwiftOverlay.cmake b/Runtimes/Supplemental/cmake/modules/FindSwiftOverlay.cmake
new file mode 100644
index 0000000000000..c40b41837ccf7
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/FindSwiftOverlay.cmake
@@ -0,0 +1,272 @@
+#[=======================================================================[.rst:
+FindSwiftOverlay
+------------
+
+Find SwiftOverlay, deferring to the associated SwiftOverlayConfig.cmake when requested.
+This is meant to find the platform overlays to be linked by the Supplemental libraries.
+
+Imported Targets
+^^^^^^^^^^^^^^^^
+
+The following :prop_tgt:`IMPORTED` TARGETS may be defined:
+
+ ``SwiftOverlay``
+
+Hint Variables
+^^^^^^^^^^^^^^
+
+ ``SDKROOT`` (environment variable)
+   Set the path to the Swift SDK Root.
+   This only affects Windows and Android builds.
+
+ ``Swift_SDKROOT``
+   Set the path to the Swift SDK installation.
+   This affects Linux, Android, and Windows builds.
+   Apple builds always use the overlay provided by the SDK.
+
+#]=======================================================================]
+
+include_guard(GLOBAL)
+
+# This was loosely modelled after other find modules
+# (namely FindGLEW), where the equivalent parameter
+# is not stored in cache (possibly because we want
+# the project importing it to be able to
+# it "immediately")
+if(NOT DEFINED SwiftOverlay_USE_STATIC_LIBS)
+  set(SwiftOverlay_USE_STATIC_LIBS OFF)
+  if(NOT BUILD_SHARED_LIBS AND NOT APPLE)
+    set(SwiftOverlay_USE_STATIC_LIBS ON)
+  endif()
+endif()
+
+if(SwiftOverlay_DIR)
+  if(${CMAKE_FIND_PACKAGE_NAME}_FIND_REQUIRED)
+    list(APPEND args REQUIRED)
+  endif()
+  if(${CMAKE_FIND_PACKAGE_NAME}_FIND_QUIETLY)
+    list(APPEND args QUIET)
+  endif()
+  find_package(SwiftOverlay CONFIG ${args})
+  return()
+endif()
+
+include(FindPackageHandleStandardArgs)
+include(PlatformInfo)
+
+if(APPLE)
+  # Darwin has its own dedicated find module,
+  # so that we can use it together with the CMake config file
+  # generated by the Overlay build system
+
+  list(APPEND swift_Builtin_float_INCLUDE_DIR_HINTS
+    "${CMAKE_OSX_SYSROOT}/usr/lib/swift")
+  list(APPEND swift_Builtin_float_LIBRARY_HINTS
+    "${CMAKE_OSX_SYSROOT}/usr/lib/swift")
+  list(APPEND swift_Builtin_float_NAMES libswift_Builtin_float.tbd)
+elseif(LINUX)
+  #ToDo(swiftlang/swift/issues/83014): Handle the static MUSL SDK case
+  list(APPEND OVERLAY_TARGET_NAMES "swiftGlibc")
+
+  # Look in the SDK
+  if (SwiftOverlay_USE_STATIC_LIBS)
+    list(APPEND swiftGlibc_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/linux")
+    list(APPEND swiftGlibc_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/linux")
+    list(APPEND swiftGlibc_NAMES libswiftGlibc.a)
+
+    list(APPEND swift_Builtin_float_INCLUDE_DIR_HINTS
+      "${CMAKE_OSX_SYSROOT}/usr/lib/swift_static/linux")
+    list(APPEND swift_Builtin_float_LIBRARY_HINTS
+      "${CMAKE_OSX_SYSROOT}/usr/lib/swift_static/linux")
+    list(APPEND swift_Builtin_float_NAMES libswift_Builtin_float.a)
+  else()
+    list(APPEND swiftGlibc_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/linux/")
+    list(APPEND swiftGlibc_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/linux")
+    list(APPEND swiftGlibc_NAMES libswiftGlibc.so)
+
+    list(APPEND swift_Builtin_float_INCLUDE_DIR_HINTS
+      "${CMAKE_OSX_SYSROOT}/usr/lib/swift/linux")
+    list(APPEND swift_Builtin_float_LIBRARY_HINTS
+      "${CMAKE_OSX_SYSROOT}/usr/lib/swift/linux")
+    list(APPEND swift_Builtin_float_NAMES libswift_Builtin_float.so)
+  endif()
+  set(swiftGlibc_MODULE_NAME "Glibc.swiftmodule")
+elseif(WIN32)
+  list(APPEND OVERLAY_TARGET_NAMES "swiftWinSDK")
+  list(APPEND OVERLAY_TARGET_NAMES "swiftCRT")
+
+  list(APPEND swiftWinSDK_INCLUDE_DIR_HINTS
+    "${Swift_SDKROOT}/usr/lib/swift/windows"
+    "$ENV{SDKROOT}/usr/lib/swift/windows")
+  list(APPEND swiftWinSDK_LIBRARY_HINTS
+    "${Swift_SDKROOT}/usr/lib/swift/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}"
+    "${Swift_SDKROOT}/usr/lib/swift"
+    "$ENV{SDKROOT}/usr/lib/swift/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}"
+    "$ENV{SDKROOT}/usr/lib/swift")
+
+  if(SwiftOverlay_USE_STATIC_LIBS)
+    list(APPEND swiftWinSDK_NAMES libswiftWinSDK.lib)
+  else()
+    list(APPEND swiftWinSDK_NAMES swiftWinSDK.lib)
+  endif()
+  list(APPEND swiftWinSDK_MODULE_NAME "WinSDK.swiftmodule")
+
+  list(APPEND swiftCRT_INCLUDE_DIR_HINTS
+    "${Swift_SDKROOT}/usr/lib/swift/windows"
+    "$ENV{SDKROOT}/usr/lib/swift/windows")
+  list(APPEND swiftCRT_LIBRARY_HINTS
+    "${Swift_SDKROOT}/usr/lib/swift/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}"
+    "${Swift_SDKROOT}/usr/lib/swift"
+    "$ENV{SDKROOT}/usr/lib/swift/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}"
+    "$ENV{SDKROOT}/usr/lib/swift")
+
+ if(SwiftOverlay_USE_STATIC_LIBS)
+    list(APPEND swiftCRT_NAMES libswiftCRT.lib)
+  else()
+    list(APPEND swiftCRT_NAMES swiftCRT.lib)
+  endif()
+  set(swiftCRT_MODULE_NAME "CRT.swiftmodule")
+
+  list(APPEND swift_Builtin_float_INCLUDE_DIR_HINTS
+    "${Swift_SDKROOT}/usr/lib/swift/windows"
+    "$ENV{SDKROOT}/usr/lib/swift/windows")
+  list(APPEND swift_Builtin_float_LIBRARY_HINTS
+    "${Swift_SDKROOT}/usr/lib/swift/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}"
+    "${Swift_SDKROOT}/usr/lib/swift"
+    "$ENV{SDKROOT}/usr/lib/swift/${${PROJECT_NAME}_PLATFORM_SUBDIR}/${${PROJECT_NAME}_ARCH_SUBDIR}"
+    "$ENV{SDKROOT}/usr/lib/swift")
+
+ if(SwiftOverlay_USE_STATIC_LIBS)
+    list(APPEND swift_Builtin_float_NAMES libswift_Builtin_float.lib)
+  else()
+    list(APPEND swift_Builtin_float_NAMES swift_Builtin_float.lib)
+  endif()
+elseif(ANDROID)
+  list(APPEND OVERLAY_TARGET_NAMES "swiftAndroid")
+
+  if (SwiftOverlay_USE_STATIC_LIBS)
+    list(APPEND swiftAndroid_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/android"
+      "$ENV{SDKROOT}/usr/lib/swift_static/android")
+    list(APPEND swiftAndroid_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "${Swift_SDKROOT}/usr/lib/swift_static"
+      "$ENV{SDKROOT}/usr/lib/swift_static/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "$ENV{SDKROOT}/usr/lib/swift_static")
+    list(APPEND swiftAndroid_NAMES libswiftAndroid.a)
+
+    list(APPEND swift_Builtin_float_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/android"
+      "$ENV{SDKROOT}/usr/lib/swift_static/android")
+    list(APPEND swift_Builtin_float_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift_static/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "${Swift_SDKROOT}/usr/lib/swift_static"
+      "$ENV{SDKROOT}/usr/lib/swift_static/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "$ENV{SDKROOT}/usr/lib/swift_static")
+    list(APPEND swift_Builtin_float_NAMES libswift_Builtin_float.a)
+  else()
+    list(APPEND swiftAndroid_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/android"
+      "$ENV{SDKROOT}/usr/lib/swift/android")
+    list(APPEND swiftAndroid_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "${Swift_SDKROOT}/usr/lib/swift"
+      "$ENV{SDKROOT}/usr/lib/swift/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "$ENV{SDKROOT}/usr/lib/swift")
+    list(APPEND swiftAndroid_NAMES libswiftAndroid.so)
+
+    list(APPEND swift_Builtin_float_INCLUDE_DIR_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/android"
+      "$ENV{SDKROOT}/usr/lib/swift/android")
+    list(APPEND swift_Builtin_float_LIBRARY_HINTS
+      "${Swift_SDKROOT}/usr/lib/swift/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "${Swift_SDKROOT}/usr/lib/swift"
+      "$ENV{SDKROOT}/usr/lib/swift/android/${${PROJECT_NAME}_ARCH_SUBDIR}"
+      "$ENV{SDKROOT}/usr/lib/swift")
+    list(APPEND swift_Builtin_float_NAMES libswift_Builtin_float.so)
+  endif()
+  set(swiftAndroid_MODULE_NAME "Android.swiftmodule")
+else()
+  message(FATAL_ERROR "FindSwiftOverlay.cmake module search not implemented for targeted platform\n"
+  " Build the Overlays for your platform and set the appropriate `SwiftOverlay_DIR` variable to"
+  " the directory containing SwiftOverlayConfig.cmake\n")
+endif()
+
+# Setup SwiftOverlay interface library and link it against the explicit
+# overlay targets
+add_library(SwiftOverlay INTERFACE)
+
+foreach(OVERLAY_TARGET ${OVERLAY_TARGET_NAMES})
+  find_path(${OVERLAY_TARGET}_INCLUDE_DIR
+    ${${OVERLAY_TARGET}_MODULE_NAME}
+    NO_CMAKE_FIND_ROOT_PATH
+    HINTS
+      ${${OVERLAY_TARGET}_INCLUDE_DIR_HINTS})
+  find_library(${OVERLAY_TARGET}_LIBRARY
+    NAMES
+      ${${OVERLAY_TARGET}_NAMES}
+    NO_CMAKE_FIND_ROOT_PATH
+    HINTS
+      ${${OVERLAY_TARGET}_LIBRARY_HINTS})
+
+  if(SwiftOverlay_USE_STATIC_LIBS)
+    add_library(${OVERLAY_TARGET} STATIC IMPORTED GLOBAL)
+  else()
+    add_library(${OVERLAY_TARGET} SHARED IMPORTED GLOBAL)
+  endif()
+
+  target_include_directories(${OVERLAY_TARGET} INTERFACE
+    "${${OVERLAY_TARGET}_INCLUDE_DIR}")
+
+  if(LINUX OR ANDROID)
+    set_target_properties(${OVERLAY_TARGET} PROPERTIES
+      IMPORTED_LOCATION "${${OVERLAY_TARGET}_LIBRARY}")
+  else()
+    set_target_properties(${OVERLAY_TARGET} PROPERTIES
+      IMPORTED_IMPLIB "${${OVERLAY_TARGET}_LIBRARY}")
+  endif()
+
+  target_link_libraries(SwiftOverlay INTERFACE
+      ${OVERLAY_TARGET})
+endforeach()
+
+find_path(swift_Builtin_float_INCLUDE_DIR
+  "_Builtin_float.swiftmodule"
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${swift_Builtin_float_INCLUDE_DIR_HINTS})
+find_library(swift_Builtin_float_LIBRARY
+  NAMES
+    ${swift_Builtin_float_NAMES}
+  NO_CMAKE_FIND_ROOT_PATH
+  HINTS
+    ${swift_Builtin_float_LIBRARY_HINTS})
+
+if(SwiftOverlay_USE_STATIC_LIBS)
+  add_library(swift_Builtin_float STATIC IMPORTED GLOBAL)
+else()
+  add_library(swift_Builtin_float SHARED IMPORTED GLOBAL)
+endif()
+
+target_include_directories(swift_Builtin_float INTERFACE
+  "${swift_Builtin_float_INCLUDE_DIR}")
+
+if(LINUX OR ANDROID)
+  set_target_properties(swift_Builtin_float PROPERTIES
+    IMPORTED_LOCATION "${swift_Builtin_float_LIBRARY}")
+else()
+  set_target_properties(swift_Builtin_float PROPERTIES
+    IMPORTED_IMPLIB "${swift_Builtin_float_LIBRARY}")
+endif()
+
+foreach(OVERLAY_TARGET ${OVERLAY_TARGET_NAMES})
+  list(APPEND vars_to_check "${OVERLAY_TARGET}_LIBRARY" "${OVERLAY_TARGET}_INCLUDE_DIR")
+endforeach()
+list(APPEND vars_to_check "swift_Builtin_float_LIBRARY" "swift_Builtin_float_INCLUDE_DIR")
+
+find_package_handle_standard_args(SwiftOverlay DEFAULT_MSG
+  ${vars_to_check})
diff --git a/Runtimes/Supplemental/cmake/modules/InstallSwiftInterface.cmake b/Runtimes/Supplemental/cmake/modules/InstallSwiftInterface.cmake
new file mode 100644
index 0000000000000..e8f5fb2021596
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/InstallSwiftInterface.cmake
@@ -0,0 +1,13 @@
+
+# Install the generated swift interface files for the target.
+function(install_swift_interface target)
+  # Swiftmodules are already in the directory structure
+  get_target_property(module_name ${target} Swift_MODULE_NAME)
+  if(NOT module_name)
+    set(module_name ${target})
+  endif()
+
+  install(DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/${module_name}.swiftmodule"
+    DESTINATION "${${PROJECT_NAME}_INSTALL_SWIFTMODULEDIR}"
+    COMPONENT ${PROJECT_NAME}_development)
+endfunction()
diff --git a/Runtimes/Supplemental/cmake/modules/LanguageVersions.cmake b/Runtimes/Supplemental/cmake/modules/LanguageVersions.cmake
new file mode 100644
index 0000000000000..706661f229ac3
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/LanguageVersions.cmake
@@ -0,0 +1,5 @@
+set(CMAKE_Swift_LANGUAGE_VERSION 5)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
+set(CMAKE_CXX_EXTENSIONS NO)
diff --git a/Runtimes/Supplemental/cmake/modules/PlatformInfo.cmake b/Runtimes/Supplemental/cmake/modules/PlatformInfo.cmake
new file mode 100644
index 0000000000000..b62a729bc8ffd
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/PlatformInfo.cmake
@@ -0,0 +1,40 @@
+include_guard(GLOBAL)
+
+if(NOT ${PROJECT_NAME}_SIZEOF_POINTER)
+  set(${PROJECT_NAME}_SIZEOF_POINTER "${CMAKE_SIZEOF_VOID_P}" CACHE STRING "Size of a pointer in bytes")
+  message(CONFIGURE_LOG "Stdlib Pointer size: ${CMAKE_SIZEOF_VOID_P}")
+  mark_as_advanced(${PROJECT_NAME}_SIZEOF_POINTER)
+endif()
+
+# TODO: This logic should migrate to CMake once CMake supports installing swiftmodules
+set(module_triple_command "${CMAKE_Swift_COMPILER}" -print-target-info)
+if(CMAKE_Swift_COMPILER_TARGET)
+  list(APPEND module_triple_command -target ${CMAKE_Swift_COMPILER_TARGET})
+endif()
+execute_process(COMMAND ${module_triple_command} OUTPUT_VARIABLE target_info_json)
+message(CONFIGURE_LOG "Swift target info: ${module_triple_command}\n"
+"${target_info_json}")
+
+if(NOT ${PROJECT_NAME}_MODULE_TRIPLE)
+  string(JSON module_triple GET "${target_info_json}" "target" "moduleTriple")
+  set(${PROJECT_NAME}_MODULE_TRIPLE "${module_triple}" CACHE STRING "Triple used for installed swift{doc,module,interface} files")
+  mark_as_advanced(${PROJECT_NAME}_MODULE_TRIPLE)
+
+  message(CONFIGURE_LOG "Swift module triple: ${module_triple}")
+endif()
+
+if(NOT ${PROJECT_NAME}_PLATFORM_SUBDIR)
+  string(JSON platform GET "${target_info_json}" "target" "platform")
+  set(${PROJECT_NAME}_PLATFORM_SUBDIR "${platform}" CACHE STRING "Platform name used for installed swift{doc,module,interface} files")
+  mark_as_advanced(${PROJECT_NAME}_PLATFORM_SUBDIR)
+
+  message(CONFIGURE_LOG "Swift platform: ${platform}")
+endif()
+
+if(NOT ${PROJECT_NAME}_ARCH_SUBDIR)
+  string(JSON arch GET "${target_info_json}" "target" "arch")
+  set(${PROJECT_NAME}_ARCH_SUBDIR "${arch}" CACHE STRING "Architecture used for setting the architecture subdirectory")
+  mark_as_advanced(${PROJECT_NAME}_ARCH_SUBDIR)
+
+  message(CONFIGURE_LOG "Swift Arch: ${arch}")
+endif()
diff --git a/Runtimes/Supplemental/cmake/modules/ResourceEmbedding.cmake b/Runtimes/Supplemental/cmake/modules/ResourceEmbedding.cmake
new file mode 100644
index 0000000000000..fe118f74da176
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/ResourceEmbedding.cmake
@@ -0,0 +1,70 @@
+function(generate_plist project_name project_version target)
+  set(PLIST_INFO_PLIST "Info.plist")
+  set(PLIST_INFO_NAME "${project_name}")
+
+  # Underscores aren't permitted in the bundle identifier.
+  string(REPLACE "_" "" PLIST_INFO_UTI "com.apple.dt.runtime.${PLIST_INFO_NAME}")
+  set(PLIST_INFO_VERSION "${project_version}")
+  set(PLIST_INFO_BUILD_VERSION "${project_version}")
+
+  set(PLIST_INFO_PLIST_OUT "${PLIST_INFO_PLIST}")
+  set(PLIST_INFO_PLIST_IN "${PROJECT_SOURCE_DIR}/${PLIST_INFO_PLIST}.in")
+
+  if(APPLE)
+    target_link_options(${target} PRIVATE
+      "SHELL:-Xlinker -sectcreate -Xlinker __TEXT -Xlinker __info_plist -Xlinker ${CMAKE_CURRENT_BINARY_DIR}/${PLIST_INFO_PLIST_OUT}")
+  endif()
+
+  configure_file(
+      "${PLIST_INFO_PLIST_IN}"
+      "${PLIST_INFO_PLIST_OUT}"
+      @ONLY
+      NEWLINE_STYLE UNIX)
+
+  set_property(TARGET ${target} APPEND PROPERTY LINK_DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/${PLIST_INFO_PLIST_OUT}")
+
+  # If Application Extensions are enabled, pass the linker flag marking
+  # the dylib as safe.
+  if (CXX_SUPPORTS_FAPPLICATION_EXTENSION AND (NOT DISABLE_APPLICATION_EXTENSION))
+    list(APPEND link_flags "-Wl,-application_extension")
+  endif()
+endfunction()
+
+# FIXME: it appears that `CMAKE_MT` evaluates to an empty string which prevents
+# the use of the variable. This aliases `MT` to `CMAKE_MT` and tries to fallback
+# to known spellings for the tool.
+if(WIN32 AND BUILD_SHARED_LIBS)
+  find_program(MT HINTS ${CMAKE_MT} NAMES mt llvm-mt REQUIRED)
+endif()
+
+function(embed_manifest target)
+  get_target_property(_EM_TARGET_TYPE ${target} TYPE)
+  if(NOT "${_EM_TARGET_TYPE}" MATCHES "SHARED_LIBRARY|EXECUTABLE")
+    return()
+  endif()
+
+  get_target_property(_EM_BINARY_DIR ${target} BINARY_DIR)
+  get_target_property(_EM_NAME ${target} NAME)
+
+  # Evaluate variables
+  file(CONFIGURE
+    OUTPUT ${_EM_BINARY_DIR}/${_EM_NAME}-${PROJECT_VERSION}.1.manifest.in
+    CONTENT [[<?xml version="1.0" encoding="utf-8" standalone="yes"?>
+<assembly manifestversion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1">
+  <assemblyIdentity
+    name="$<TARGET_NAME:@target@>"
+    processorArchitecture="@CMAKE_SYSTEM_PROCESSOR@"
+    type="win32"
+    version="@PROJECT_VERSION@" />
+  <file name="$<TARGET_FILE_NAME:@target@>" />
+</assembly>]])
+  # Evaluate generator expression
+  file(GENERATE
+    OUTPUT ${_EM_BINARY_DIR}/${_EM_NAME}-${PROJECT_VERSION}.1.manifest
+    INPUT ${_EM_BINARY_DIR}/${_EM_NAME}-${PROJECT_VERSION}.1.manifest.in)
+
+  if(WIN32)
+    add_custom_command(TARGET ${target} POST_BUILD
+      COMMAND "${MT}" -nologo -manifest "${_EM_BINARY_DIR}/${_EM_NAME}-${PROJECT_VERSION}.1.manifest" "-outputresource:$<TARGET_FILE:${target}>;#1")
+  endif()
+endfunction()
diff --git a/Runtimes/Supplemental/cmake/modules/SwiftCallingConventions.cmake b/Runtimes/Supplemental/cmake/modules/SwiftCallingConventions.cmake
new file mode 100644
index 0000000000000..ceb3145e10d41
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/SwiftCallingConventions.cmake
@@ -0,0 +1,28 @@
+include(CheckSourceCompiles)
+include(CheckCompilerFlag)
+
+check_source_compiles(CXX
+"#if !(__has_attribute(swiftcall) && \
+  __has_attribute(swift_context) && \
+  __has_attribute(swift_error_result) && \
+  __has_attribute(swift_indirect_result))
+#error CXX compiler must support Swift calling conventions
+#endif
+int main(void) { return 0; }"
+HAVE_SWIFTCALL)
+
+if(NOT HAVE_SWIFTCALL)
+  message(SEND_ERROR "CXX Compiler must support Swift calling conventions")
+endif()
+
+check_source_compiles(CXX
+"#if !(__has_attribute(swiftasynccall) && \
+  __has_attribute(swift_async_context))
+#error CXX compiler must support Swift async calling conventions
+#endif
+int main(void) { return 0; }"
+HAVE_SWIFT_ASYNC_CALL)
+
+if(NOT HAVE_SWIFT_ASYNC_CALL)
+  message(SEND_ERROR "CXX Compiler must support Swift async calling conventions")
+endif()
diff --git a/Runtimes/Supplemental/cmake/modules/gyb.cmake b/Runtimes/Supplemental/cmake/modules/gyb.cmake
new file mode 100644
index 0000000000000..c7d487d8f4e14
--- /dev/null
+++ b/Runtimes/Supplemental/cmake/modules/gyb.cmake
@@ -0,0 +1,47 @@
+find_package(Python3 REQUIRED COMPONENTS Interpreter)
+
+# Create a target to expand a gyb source
+# target_name: Name of the target
+# FLAGS  list of flags passed to gyb
+# DEPENDS list of dependencies
+# COMMENT Custom comment
+function(gyb_expand source output)
+  set(flags)
+  set(arguments)
+  set(multival_arguments FLAGS DEPENDS)
+  cmake_parse_arguments(GYB "${flags}" "${arguments}" "${multival_arguments}" ${ARGN})
+
+  get_filename_component(full_output_path ${output} ABSOLUTE BASE_DIR "${CMAKE_CURRENT_BINARY_DIR}")
+  get_filename_component(dir "${full_output_path}" DIRECTORY)
+  get_filename_component(fname "${full_output_path}" NAME)
+
+  file(READ "${source}" gyb_src)
+  string(REGEX MATCHALL "\\\$\{[\r\n\t ]*gyb.expand\\\([\r\n\t ]*[\'\"]([^\'\"]*)[\'\"]" gyb_expand_matches "${gyb_src}")
+  foreach(match ${gyb_expand_matches})
+    string(REGEX MATCH "[\'\"]\([^\'\"]*\)[\'\"]" gyb_dep "${match}")
+    list(APPEND gyb_expand_deps "${CMAKE_MATCH_1}")
+  endforeach()
+  list(REMOVE_DUPLICATES gyb_expand_deps)
+
+  set(utils_dir "${${PROJECT_NAME}_SWIFTC_SOURCE_DIR}/utils/")
+  set(gyb_tool "${utils_dir}/gyb")
+
+  # All the tidbits to track for changes
+  list(APPEND GYB_DEPENDS
+    "${source}"
+    "${utils_dir}/GYBUnicodeDataUtils.py"
+    "${utils_dir}/SwiftIntTypes.py"
+    "${utils_dir}/SwiftFloatingPointTypes.py"
+    "${utils_dir}/UnicodeData/GraphemeBreakProperty.txt"
+    "${utils_dir}/UnicodeData/GraphemeBreakTest.txt"
+    "${utils_dir}/gyb_stdlib_support.py")
+  add_custom_command(
+    OUTPUT  "${full_output_path}"
+    COMMAND "${CMAKE_COMMAND}" -E make_directory "${dir}"
+    COMMAND "${CMAKE_COMMAND}" -E env "$<TARGET_FILE:Python3::Interpreter>" "${gyb_tool}" ${GYB_FLAGS} -o "${full_output_path}.tmp" "${source}"
+    COMMAND "${CMAKE_COMMAND}" -E copy_if_different "${full_output_path}.tmp" "${full_output_path}"
+    COMMAND "${CMAKE_COMMAND}" -E remove "${full_output_path}.tmp"
+    DEPENDS ${gyb_tool} ${gyb_tool}.py ${GYB_DEPENDS} ${gyb_expand_deps}
+    COMMENT "Generating GYB source ${fname} from ${source}"
+    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}")
+endfunction()
diff --git a/Runtimes/cmake/modules/SwiftProjectVersion.cmake b/Runtimes/cmake/modules/SwiftProjectVersion.cmake
new file mode 100644
index 0000000000000..36b7ae6b2db63
--- /dev/null
+++ b/Runtimes/cmake/modules/SwiftProjectVersion.cmake
@@ -0,0 +1,23 @@
+# This module sets the Swift version number variable consistently across the
+# Swift runtime projects.
+
+## Result Variable
+#
+# ``SWIFT_RUNTIME_VERSION``
+#   The computed version number applied to apply to the project.
+#   If ``SWIFT_RUNTIME_VERSION`` is set prior to entering the module, the version
+#   is not modified.
+
+block(PROPAGATE SWIFT_RUNTIME_VERSION)
+  if(SWIFT_RUNTIME_VERSION)
+    return()
+  endif()
+
+  if($ENV{BUILD_NUMBER})
+    # Microsoft build numbers limit each version number component to [0 - 65535]
+    # https://learn.microsoft.com/en-us/windows/win32/sbscs/assembly-versions
+    math(EXPR BUILD_NUMBER "$ENV{BUILD_NUMBER} % 65535")
+    set(BUILD_NUMBER ".${BUILD_NUMBER}")
+  endif()
+  set(SWIFT_RUNTIME_VERSION 6.3.0${BUILD_NUMBER})
+endblock()
diff --git a/Runtimes/cmake/toolchains/Darwin.toolchain.cmake b/Runtimes/cmake/toolchains/Darwin.toolchain.cmake
new file mode 100644
index 0000000000000..1cc1ddea00f33
--- /dev/null
+++ b/Runtimes/cmake/toolchains/Darwin.toolchain.cmake
@@ -0,0 +1,106 @@
+# Toolchain configuration when compiling for Darwin Platforms
+set(CMAKE_SYSTEM_NAME Darwin)
+set(CMAKE_Swift_COMPILER_WORKS YES)
+set(CMAKE_C_COMPILER_WORKS YES)
+set(CMAKE_CXX_COMPILER_WORKS YES)
+
+find_program(XCRUN_EXECUTABLE NAMES "xcrun" REQUIRED)
+
+if(NOT CMAKE_OSX_SYSROOT)
+  if(NOT DEFINED ENV{SDKROOT})
+    message(FATAL_ERROR "`CMAKE_OSX_SYSROOT` and the 'SDKROOT' environment variable are not set")
+  endif()
+
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --show-sdk-path -sdk $ENV{SDKROOT}
+    OUTPUT_VARIABLE SDKROOT
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+  if(NOT EXISTS ${SDKROOT})
+    message(FATAL_ERROR "SDKROOT could not be detected!")
+  endif()
+
+  message(STATUS "Using SDKROOT: ${SDKROOT}")
+  set(CMAKE_OSX_SYSROOT "${SDKROOT}" CACHE FILEPATH "")
+endif()
+
+if(NOT CMAKE_C_COMPILER)
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find clang
+    OUTPUT_VARIABLE CMAKE_C_COMPILER
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using C compiler ${CMAKE_C_COMPILER}")
+endif()
+
+if(NOT CMAKE_CXX_COMPILER)
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find clang++
+    OUTPUT_VARIABLE CMAKE_CXX_COMPILER
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using CXX compiler ${CMAKE_CXX_COMPILER}")
+endif()
+
+if(NOT CMAKE_Swift_COMPILER)
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find swiftc
+    OUTPUT_VARIABLE CMAKE_Swift_COMPILER
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using Swift compiler ${CMAKE_Swift_COMPILER}")
+endif()
+
+if(NOT CMAKE_AR)
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find ar
+    OUTPUT_VARIABLE CMAKE_AR
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using ar ${CMAKE_AR}")
+endif()
+
+if(NOT CMAKE_RANLIB)
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find ranlib
+    OUTPUT_VARIABLE CMAKE_RANLIB
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using ranlib ${CMAKE_RANLIB}")
+endif()
+
+if(NOT CMAKE_STRIP)
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find strip
+    OUTPUT_VARIABLE CMAKE_STRIP
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using strip ${CMAKE_STRIP}")
+endif()
+
+if(NOT CMAKE_DSYMUTIL)
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find dsymutil
+    OUTPUT_VARIABLE CMAKE_DSYMUTIL
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using dsymutil ${CMAKE_DSYMUTIL}")
+endif()
+
+if(NOT CMAKE_LIBTOOL)
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find libtool
+   OUTPUT_VARIABLE CMAKE_LIBTOOL
+   ERROR_QUIET
+   OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using libtool ${CMAKE_LIBTOOL}")
+endif()
+
+if(NOT CMAKE_CODESIGN)
+  execute_process(COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find codesign
+   OUTPUT_VARIABLE CMAKE_CODESIGN
+   ERROR_QUIET
+   OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using codesign ${CMAKE_CODESIGN}")
+endif()
+
+if(NOT CMAKE_CODESIGN_ALLOCATE)
+  execute_process(
+    COMMAND "${XCRUN_EXECUTABLE}" --sdk ${CMAKE_OSX_SYSROOT} --find codesign_allocate
+    OUTPUT_VARIABLE CMAKE_CODESIGN_ALLOCATE
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  message(STATUS "Using codesign_allocate ${CMAKE_CODESIGN_ALLOCATE}")
+endif()
diff --git a/SwiftCompilerSources/CMakeLists.txt b/SwiftCompilerSources/CMakeLists.txt
index f38418922440c..f559638880537 100644
--- a/SwiftCompilerSources/CMakeLists.txt
+++ b/SwiftCompilerSources/CMakeLists.txt
@@ -6,6 +6,8 @@
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
+include(SwiftUtils)
+
 # Following function are needed as a workaround until it's possible to compile
 # swift code with cmake's builtin swift support.
 
@@ -101,19 +103,12 @@ function(add_swift_compiler_modules_library name)
   set(swift_compile_options
       "-color-diagnostics"
       "-Xfrontend" "-validate-tbd-against-ir=none"
-      "${cxx_interop_flag}"
+      "-cxx-interoperability-mode=default"
       "-Xfrontend" "-disable-target-os-checking"
       "-Xcc" "-std=c++17"
       "-Xcc" "-DCOMPILED_WITH_SWIFT" "-Xcc" "-DSWIFT_TARGET"
       "-Xcc" "-UIBOutlet" "-Xcc" "-UIBAction" "-Xcc" "-UIBInspectable")
 
-  # Prior to 5.9, we have to use the experimental flag for C++ interop.
-  if (CMAKE_Swift_COMPILER_VERSION VERSION_LESS 5.9)
-    list(APPEND swift_compile_options "-Xfrontend" "-enable-experimental-cxx-interop")
-  else()
-    list(APPEND swift_compile_options "-cxx-interoperability-mode=default")
-  endif()
-
   if (NOT BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS")
     if(SWIFT_MIN_RUNTIME_VERSION)
       list(APPEND swift_compile_options
@@ -128,10 +123,19 @@ function(add_swift_compiler_modules_library name)
     list(APPEND swift_compile_options "-Xfrontend" "-cxx-interop-use-opaque-pointer-for-moveonly")
   endif()
 
-  if(CMAKE_BUILD_TYPE STREQUAL "Debug")
+  is_build_type_with_debuginfo("${CMAKE_BUILD_TYPE}" debug)
+  if (debug)
     list(APPEND swift_compile_options "-g")
-  else()
-    list(APPEND swift_compile_options "-O" "-cross-module-optimization")
+  endif()
+
+  is_build_type_optimized("${CMAKE_BUILD_TYPE}" optimized)
+  if (optimized)
+    if("${CMAKE_BUILD_TYPE}" STREQUAL "MinSizeRel")
+      list(APPEND swift_compile_options "-Osize")
+    else()
+      list(APPEND swift_compile_options "-O")
+    endif()
+    list(APPEND swift_compile_options "-cross-module-optimization")
   endif()
 
   if(LLVM_ENABLE_ASSERTIONS)
@@ -202,6 +206,18 @@ function(add_swift_compiler_modules_library name)
 
     # Workaround for https://github.com/swiftlang/llvm-project/issues/7172
     list(APPEND swift_compile_options "-Xcc" "-Xclang" "-Xcc" "-fmodule-format=raw")
+
+  elseif(swift_exec_bin_dir MATCHES ".*/swiftly/bin")
+    # Detect and handle swiftly-managed hosts.
+    execute_process(COMMAND swiftly use --print-location
+      OUTPUT_VARIABLE swiftly_dir
+      ERROR_VARIABLE err)
+    if(err)
+      message(SEND_ERROR "Failed to find swiftly Swift compiler")
+    endif()
+    string(STRIP "${swiftly_dir}" swiftly_dir)
+
+    list(APPEND sdk_option "-I" "${swiftly_dir}/usr/lib" "-I" "${swiftly_dir}/usr/lib")
   else()
     list(APPEND sdk_option "-I" "${swift_exec_bin_dir}/../lib" "-I" "${sdk_path}/usr/lib")
   endif()
@@ -286,12 +302,6 @@ function(add_swift_compiler_modules_library name)
   endforeach()
 
   # Create a static library containing all module object files.
-  if (XCODE)
-    # Xcode does not compile libraries that contain only object files.
-    # Therefore, it fails to create the static library. As a workaround,
-    # we add an empty source file force_lib.c to the target.
-    set(all_obj_files force_lib.c ${all_obj_files})
-  endif()
   add_library(${name} STATIC ${all_obj_files})
   add_dependencies(${name} ${all_module_targets})
   set_target_properties(${name} PROPERTIES LINKER_LANGUAGE CXX)
@@ -341,7 +351,7 @@ else()
         message(FATAL_ERROR "The Swift compiler (${CMAKE_Swift_COMPILER}) differs from the Swift compiler in SWIFT_NATIVE_SWIFT_TOOLS_PATH (${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/swiftc).")
       endif()
 
-      set(min_supported_swift_version 5.8)
+      set(min_supported_swift_version 5.9)
       if(CMAKE_Swift_COMPILER_VERSION VERSION_LESS "${min_supported_swift_version}")
         message(FATAL_ERROR
             "Outdated Swift compiler: building with host tools requires Swift ${min_supported_swift_version} or newer. "
diff --git a/SwiftCompilerSources/Sources/AST/CMakeLists.txt b/SwiftCompilerSources/Sources/AST/CMakeLists.txt
index 63a8ec912e1d9..303857f3f98d7 100644
--- a/SwiftCompilerSources/Sources/AST/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/AST/CMakeLists.txt
@@ -12,6 +12,7 @@ add_swift_compiler_module(AST
   SOURCES
     Declarations.swift
     Conformance.swift
+    DiagnosticEngine.swift
     GenericSignature.swift
     Registration.swift
     SubstitutionMap.swift
diff --git a/SwiftCompilerSources/Sources/AST/Conformance.swift b/SwiftCompilerSources/Sources/AST/Conformance.swift
index 1d7510d9d217e..f67c942924c3d 100644
--- a/SwiftCompilerSources/Sources/AST/Conformance.swift
+++ b/SwiftCompilerSources/Sources/AST/Conformance.swift
@@ -17,7 +17,7 @@ import ASTBridging
 /// members to the type (or extension) members that provide the functionality for the concrete type.
 ///
 ///  TODO: Ideally, `Conformance` should be an enum
-public struct Conformance: CustomStringConvertible, NoReflectionChildren {
+public struct Conformance: CustomStringConvertible, Hashable, NoReflectionChildren {
   public let bridged: BridgedConformance
 
   public init(bridged: BridgedConformance) {
@@ -28,6 +28,14 @@ public struct Conformance: CustomStringConvertible, NoReflectionChildren {
     return String(taking: bridged.getDebugDescription())
   }
 
+  public func hash(into hasher: inout Hasher) {
+    hasher.combine(bridged.opaqueValue)
+  }
+
+  public static func ==(lhs: Conformance, rhs: Conformance) -> Bool {
+    lhs.bridged.opaqueValue == rhs.bridged.opaqueValue
+  }
+
   public var isConcrete: Bool { bridged.isConcrete() }
 
   public var isValid: Bool { bridged.isValid() }
@@ -37,7 +45,7 @@ public struct Conformance: CustomStringConvertible, NoReflectionChildren {
     return Type(bridged: bridged.getType())
   }
 
-  public var proto: ProtocolDecl {
+  public var `protocol`: ProtocolDecl {
     return bridged.getRequirement().getAs(ProtocolDecl.self)
   }
   public var isSpecialized: Bool {
diff --git a/SwiftCompilerSources/Sources/AST/Declarations.swift b/SwiftCompilerSources/Sources/AST/Declarations.swift
index b20349e6cde15..2041d32fd22de 100644
--- a/SwiftCompilerSources/Sources/AST/Declarations.swift
+++ b/SwiftCompilerSources/Sources/AST/Declarations.swift
@@ -23,6 +23,9 @@ public class Decl: CustomStringConvertible, Hashable {
   /// The module in which this declaration resides.
   public var parentModule: ModuleDecl { bridged.getModuleContext().getAs(ModuleDecl.self) }
 
+  /// The parent DeclContext if it is a Decl.
+  public var parent: Decl? { bridged.getParent().decl }
+
   // True if this declaration is imported from C/C++/ObjC.
   public var hasClangNode: Bool { bridged.hasClangNode() }
 
@@ -55,7 +58,9 @@ public class NominalTypeDecl: GenericTypeDecl {
   }
 }
 
-final public class EnumDecl: NominalTypeDecl {}
+final public class EnumDecl: NominalTypeDecl {
+  public var hasRawType: Bool { bridged.Enum_hasRawType() }
+}
 
 final public class StructDecl: NominalTypeDecl {
   public var hasUnreferenceableStorage: Bool { bridged.Struct_hasUnreferenceableStorage() }
@@ -69,7 +74,9 @@ final public class ClassDecl: NominalTypeDecl {
   }
 }
 
-final public class ProtocolDecl: NominalTypeDecl {}
+final public class ProtocolDecl: NominalTypeDecl {
+  public var requiresClass: Bool { bridged.ProtocolDecl_requiresClass() }
+}
 
 final public class BuiltinTupleDecl: NominalTypeDecl {}
 
@@ -109,7 +116,9 @@ final public class AccessorDecl: FuncDecl {}
 
 final public class MacroDecl: ValueDecl {}
 
-final public class EnumElementDecl: ValueDecl {}
+final public class EnumElementDecl: ValueDecl {
+  public var hasAssociatedValues: Bool { bridged.EnumElementDecl_hasAssociatedValues() }
+}
 
 final public class ExtensionDecl: Decl {}
 
@@ -117,6 +126,8 @@ final public class TopLevelCodeDecl: Decl {}
 
 final public class ImportDecl: Decl {}
 
+final public class UsingDecl: Decl {}
+
 final public class PrecedenceGroupDecl: Decl {}
 
 final public class MissingDecl: Decl {}
@@ -148,3 +159,9 @@ extension OptionalBridgedDeclObj {
   public var decl: Decl? { obj.getAs(Decl.self) }
   public func getAs<T: Decl>(_ declType: T.Type) -> T? { obj.getAs(T.self) }
 }
+
+extension Optional where Wrapped == Decl {
+  public var bridged: OptionalBridgedDeclObj {
+    OptionalBridgedDeclObj(self?.bridged.obj)
+  }
+}
diff --git a/SwiftCompilerSources/Sources/AST/DiagnosticEngine.swift b/SwiftCompilerSources/Sources/AST/DiagnosticEngine.swift
new file mode 100644
index 0000000000000..08ae4a83cafc6
--- /dev/null
+++ b/SwiftCompilerSources/Sources/AST/DiagnosticEngine.swift
@@ -0,0 +1,186 @@
+//===--- DiagnosticEngine.swift -------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import ASTBridging
+import Basic
+
+public typealias DiagID = swift.DiagID
+
+public protocol DiagnosticArgument {
+  func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void)
+}
+extension String: DiagnosticArgument {
+  public func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
+    _withBridgedStringRef { fn(BridgedDiagnosticArgument($0)) }
+  }
+}
+extension StringRef: DiagnosticArgument {
+  public func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
+    fn(BridgedDiagnosticArgument(_bridged))
+  }
+}
+extension Int: DiagnosticArgument {
+  public func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
+    fn(BridgedDiagnosticArgument(self))
+  }
+}
+extension Type: DiagnosticArgument {
+  public func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
+    fn(bridged.asDiagnosticArgument())
+  }
+}
+
+public struct DiagnosticFixIt {
+  let start: SourceLoc
+  let byteLength: Int
+  let text: String
+
+  init(start: SourceLoc, byteLength: Int, replacement text: String) {
+    self.start = start
+    self.byteLength = byteLength
+    self.text = text
+  }
+
+  func withBridgedDiagnosticFixIt(_ fn: (BridgedDiagnosticFixIt) -> Void) {
+    text._withBridgedStringRef { bridgedTextRef in
+      let bridgedDiagnosticFixIt = BridgedDiagnosticFixIt(
+        start.bridged, UInt32(byteLength),
+        bridgedTextRef)
+      fn(bridgedDiagnosticFixIt)
+    }
+  }
+}
+
+public struct DiagnosticEngine {
+  private let bridged: BridgedDiagnosticEngine
+
+  public init(bridged: BridgedDiagnosticEngine) {
+    self.bridged = bridged
+  }
+  init?(bridged: BridgedNullableDiagnosticEngine) {
+    guard let raw = bridged.raw else {
+      return nil
+    }
+    self.bridged = BridgedDiagnosticEngine(raw: raw)
+  }
+
+  public func diagnose(_ id: DiagID,
+                       _ args: [DiagnosticArgument],
+                       at position: SourceLoc?,
+                       highlight: CharSourceRange? = nil,
+                       fixIts: [DiagnosticFixIt] = []) {
+    let bridgedSourceLoc = position.bridgedLocation
+    let highlightStart: swift.SourceLoc
+    let highlightLength: UInt32
+    if let highlight = highlight {
+      highlightStart = highlight.start.bridged
+      highlightLength = highlight.byteLength
+    } else {
+      highlightStart = .init()
+      highlightLength = 0
+    }
+    var bridgedArgs: [BridgedDiagnosticArgument] = []
+    var bridgedFixIts: [BridgedDiagnosticFixIt] = []
+
+    // Build a higher-order function to wrap every 'withBridgedXXX { ... }'
+    // calls, so we don't escape anything from the closure. 'bridgedArgs' and
+    // 'bridgedFixIts' are temporary storage to store bridged values. So they
+    // should not be used after the closure is executed.
+ 
+    var closure: () -> Void = {
+      bridgedArgs.withBridgedArrayRef { bridgedArgsRef in
+        bridgedFixIts.withBridgedArrayRef { bridgedFixItsRef in
+          bridged.diagnose(at: bridgedSourceLoc, id, bridgedArgsRef,
+                           highlightAt: highlightStart,
+                           highlightLength: highlightLength,
+                           fixIts: bridgedFixItsRef)
+        }
+      }
+    }
+    // 'reversed()' because the closure should be wrapped in that order.
+    for arg in args.reversed() {
+      closure = { [closure, arg] in
+        arg._withBridgedDiagnosticArgument { bridgedArg in
+          bridgedArgs.append(bridgedArg)
+          closure()
+        }
+      }
+    }
+    // 'reversed()' because the closure should be wrapped in that order.
+    for fixIt in fixIts.reversed() {
+      closure = { [closure, fixIt] in
+        fixIt.withBridgedDiagnosticFixIt { bridgedFixIt in
+          bridgedFixIts.append(bridgedFixIt)
+          closure()
+        }
+      }
+    }
+
+    closure()
+  }
+
+  // FIXME: Remove this overload once https://github.com/swiftlang/swift/issues/82318 is fixed.
+  public func diagnose(
+    _ id: DiagID,
+    arguments args: [DiagnosticArgument],
+    at position: SourceLoc?,
+    highlight: CharSourceRange? = nil,
+    fixIts: [DiagnosticFixIt] = []
+  ) {
+    diagnose(id, args, at: position, highlight: highlight, fixIts: fixIts)
+  }
+
+  public func diagnose(_ id: DiagID,
+                       _ args: DiagnosticArgument...,
+                       at position: SourceLoc?,
+                       highlight: CharSourceRange? = nil,
+                       fixIts: DiagnosticFixIt...) {
+    diagnose(id, args, at: position, highlight: highlight, fixIts: fixIts)
+  }
+
+  public func diagnose<SourceLocation: ProvidingSourceLocation>(_ diagnostic: Diagnostic<SourceLocation>) {
+    let loc = diagnostic.location.getSourceLocation(diagnosticEngine: self)
+    diagnose(diagnostic.id, diagnostic.arguments, at: loc)
+  }
+
+  /// Loads the file at `path` and returns a `SourceLoc` pointing to `line` and `column` in the file.
+  /// Returns nil if the file cannot be loaded.
+  public func getLocationFromExternalSource(path: StringRef, line: Int, column: Int) -> SourceLoc? {
+    return SourceLoc(bridged: bridged.getLocationFromExternalSource(path: path._bridged, line: line, column: column))
+  }
+}
+
+/// Something which can provide a `SourceLoc` for diagnostics.
+public protocol ProvidingSourceLocation {
+  func getSourceLocation(diagnosticEngine: DiagnosticEngine) -> SourceLoc?
+}
+
+extension SourceLoc: ProvidingSourceLocation {
+  public func getSourceLocation(diagnosticEngine: DiagnosticEngine) -> SourceLoc? { self }
+}
+
+/// A utility struct which allows throwing a Diagnostic.
+public struct Diagnostic<SourceLocation: ProvidingSourceLocation> : Error {
+  public let id: DiagID
+  public let arguments: [DiagnosticArgument]
+  public let location: SourceLocation
+
+  public init(_ id: DiagID, _ arguments: DiagnosticArgument..., at location: SourceLocation) {
+    self.init(id, arguments, at: location)
+  }
+
+  public init(_ id: DiagID, _ arguments: [DiagnosticArgument], at location: SourceLocation) {
+    self.id = id
+    self.arguments = arguments
+    self.location = location
+  }
+}
diff --git a/SwiftCompilerSources/Sources/AST/GenericSignature.swift b/SwiftCompilerSources/Sources/AST/GenericSignature.swift
index e490a7ee6e828..64b858e9b4bd2 100644
--- a/SwiftCompilerSources/Sources/AST/GenericSignature.swift
+++ b/SwiftCompilerSources/Sources/AST/GenericSignature.swift
@@ -29,4 +29,10 @@ public struct GenericSignature: CustomStringConvertible, NoReflectionChildren {
   public var genericParameters: TypeArray {
     TypeArray(bridged: bridged.getGenericParams())
   }
+
+  public func mapTypeIntoContext(_ type: Type) -> Type {
+    Type(bridged: bridged.mapTypeIntoContext(type.bridged))
+  }
+
+  public var isEmpty: Bool { bridged.impl == nil }
 }
diff --git a/SwiftCompilerSources/Sources/AST/Registration.swift b/SwiftCompilerSources/Sources/AST/Registration.swift
index f1d09ebf4190d..6c4f62bf69cb7 100644
--- a/SwiftCompilerSources/Sources/AST/Registration.swift
+++ b/SwiftCompilerSources/Sources/AST/Registration.swift
@@ -36,6 +36,7 @@ public func registerAST() {
   registerDecl(ExtensionDecl.self)
   registerDecl(TopLevelCodeDecl.self)
   registerDecl(ImportDecl.self)
+  registerDecl(UsingDecl.self)
   registerDecl(PrecedenceGroupDecl.self)
   registerDecl(MissingDecl.self)
   registerDecl(MissingMemberDecl.self)
diff --git a/SwiftCompilerSources/Sources/AST/SubstitutionMap.swift b/SwiftCompilerSources/Sources/AST/SubstitutionMap.swift
index 494a55e35749d..c967fe543b1d6 100644
--- a/SwiftCompilerSources/Sources/AST/SubstitutionMap.swift
+++ b/SwiftCompilerSources/Sources/AST/SubstitutionMap.swift
@@ -68,7 +68,7 @@ public struct SubstitutionMap: CustomStringConvertible, NoReflectionChildren {
     TypeArray(bridged: bridged.getReplacementTypes())
   }
 
-  /// The single replacement type if it's guarnateed that the substitution map has a single replacement type.
+  /// The single replacement type if it's guaranteed that the substitution map has a single replacement type.
   public var replacementType: Type {
     assert(replacementTypes.count == 1)
     return replacementTypes[0]
diff --git a/SwiftCompilerSources/Sources/AST/Type.swift b/SwiftCompilerSources/Sources/AST/Type.swift
index 77d8646f9529c..c193387800f1a 100644
--- a/SwiftCompilerSources/Sources/AST/Type.swift
+++ b/SwiftCompilerSources/Sources/AST/Type.swift
@@ -14,7 +14,7 @@ import Basic
 import ASTBridging
 
 /// A Swift type.
-/// It is not necessarily canoncial, e.g. typealiases are not resolved.
+/// It is not necessarily canonical, e.g. typealiases are not resolved.
 public struct Type: TypeProperties, CustomStringConvertible, NoReflectionChildren {
   public enum TraitResult {
     case isNot
@@ -48,6 +48,10 @@ public struct Type: TypeProperties, CustomStringConvertible, NoReflectionChildre
 
   public var instanceTypeOfMetatype: Type { Type(bridged: bridged.getInstanceTypeOfMetatype()) }
 
+  public var staticTypeOfDynamicSelf: Type { Type(bridged: bridged.getStaticTypeOfDynamicSelf()) }
+
+  public var interfaceTypeOfArchetype: Type { Type(bridged: bridged.getInterfaceTypeOfArchetype()) }
+
   public var superClassType: Type? {
     precondition(isClass)
     let bridgedSuperClassTy = bridged.getSuperClassType()
@@ -62,10 +66,6 @@ public struct Type: TypeProperties, CustomStringConvertible, NoReflectionChildre
   public func subst(with substitutionMap: SubstitutionMap) -> Type {
     return Type(bridged: bridged.subst(substitutionMap.bridged))
   }
-
-  public func subst(type: Type, with targetType: Type) -> Type {
-    return Type(bridged: bridged.subst(type.bridged, targetType.bridged))
-  }
 }
 
 /// A Type that is statically known to be canonical.
@@ -86,10 +86,6 @@ public struct CanonicalType: TypeProperties, CustomStringConvertible, NoReflecti
   public func subst(with substitutionMap: SubstitutionMap) -> CanonicalType {
     return rawType.subst(with: substitutionMap).canonical
   }
-
-  public func subst(type: CanonicalType, with targetType: CanonicalType) -> CanonicalType {
-    return self.rawType.subst(type: type.rawType, with: targetType.rawType).canonical
-  }
 }
 
 /// Implements the common members of `AST.Type`, `AST.CanonicalType` and `SIL.Type`.
@@ -112,6 +108,7 @@ extension TypeProperties {
 
   public var isBuiltinFloat: Bool { rawType.bridged.isBuiltinFloat() }
   public var isBuiltinVector: Bool { rawType.bridged.isBuiltinVector() }
+  public var isBuiltinFixedArray: Bool { rawType.bridged.isBuiltinFixedArray() }
 
   public var isClass: Bool {
     if let nominal = nominal, nominal is ClassDecl {
@@ -136,14 +133,19 @@ extension TypeProperties {
 
   public var isTuple: Bool { rawType.bridged.isTuple() }
   public var isFunction: Bool { rawType.bridged.isFunction() }
+  public var isArchetype: Bool { rawType.bridged.isArchetype() }
   public var isExistentialArchetype: Bool { rawType.bridged.isExistentialArchetype() }
   public var isExistentialArchetypeWithError: Bool { rawType.bridged.isExistentialArchetypeWithError() }
+  public var isRootArchetype: Bool { rawType.interfaceTypeOfArchetype.isGenericTypeParameter }
+  public var isRootExistentialArchetype: Bool { isExistentialArchetype && isRootArchetype }
   public var isExistential: Bool { rawType.bridged.isExistential() }
   public var isClassExistential: Bool { rawType.bridged.isClassExistential() }
+  public var isGenericTypeParameter: Bool { rawType.bridged.isGenericTypeParam() }
   public var isUnownedStorageType: Bool { return rawType.bridged.isUnownedStorageType() }
   public var isMetatype: Bool { rawType.bridged.isMetatypeType() }
   public var isExistentialMetatype: Bool { rawType.bridged.isExistentialMetatypeType() }
   public var isDynamicSelf: Bool { rawType.bridged.isDynamicSelf()}
+  public var isBox: Bool { rawType.bridged.isBox() }
 
   /// True if this is the type which represents an integer literal used in a type position.
   /// For example `N` in `struct T<let N: Int> {}`
@@ -184,13 +186,33 @@ extension TypeProperties {
   public var hasArchetype: Bool { rawType.bridged.hasArchetype() }
   public var hasTypeParameter: Bool { rawType.bridged.hasTypeParameter() }
   public var hasLocalArchetype: Bool { rawType.bridged.hasLocalArchetype() }
+  public var hasDynamicSelf: Bool { rawType.bridged.hasDynamicSelf() }
   public var isEscapable: Bool { rawType.bridged.isEscapable() }
   public var isNoEscape: Bool { rawType.bridged.isNoEscape() }
+  public var isBuiltinType: Bool { rawType.bridged.isBuiltinType() }
+  public var archetypeRequiresClass: Bool { rawType.bridged.archetypeRequiresClass() }
 
   public var representationOfMetatype: AST.`Type`.MetatypeRepresentation {
     rawType.bridged.getRepresentationOfMetatype().representation
   }
 
+  public var builtinFixedArrayElementType: CanonicalType {
+    CanonicalType(bridged: rawType.bridged.getBuiltinFixedArrayElementType())
+  }
+  public var builtinFixedArraySizeType: CanonicalType {
+    CanonicalType(bridged: rawType.bridged.getBuiltinFixedArraySizeType())
+  }
+
+  /// Returns the value of an integer value type (see `isInteger`).
+  /// Returns nil if the value is not representable in an `Int`.
+  public var valueOfInteger: Int? {
+    let optionalInt = rawType.bridged.getValueOfIntegerType()
+    if optionalInt.hasValue {
+      return optionalInt.value
+    }
+    return nil
+  }
+
   /// Assumes this is a nominal type. Returns a substitution map that sends each
   /// generic parameter of the declaration's generic signature to the corresponding
   /// generic argument of this nominal type.
@@ -207,7 +229,7 @@ extension TypeProperties {
     rawType.bridged.getNominalOrBoundGenericNominal().getAs(NominalTypeDecl.self)
   }
 
-  /// Performas a global conformance lookup for this type for `protocol`.
+  /// Performs a global conformance lookup for this type for `protocol`.
   /// It checks conditional requirements.
   ///
   /// This type must be a contextualized type. It must not contain type parameters.
diff --git a/SwiftCompilerSources/Sources/Basic/SourceLoc.swift b/SwiftCompilerSources/Sources/Basic/SourceLoc.swift
index 7a631452b98a6..7eb37a720becb 100644
--- a/SwiftCompilerSources/Sources/Basic/SourceLoc.swift
+++ b/SwiftCompilerSources/Sources/Basic/SourceLoc.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
+// Copyright (c) 2022 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -12,26 +12,25 @@
 
 import BasicBridging
 
+/// Represents a location in source code.
+/// It is basically a pointer into a buffer of the loaded source file (managed by `DiagnosticEngine`).
+/// In contrast to just having a filename+line+column, this allows displaying the context around
+/// the location when printing diagnostics.
 public struct SourceLoc {
-  /// Points into a source file.
-  public let bridged: BridgedSourceLoc
+  public let bridged: swift.SourceLoc
 
-  public init?(bridged: BridgedSourceLoc) {
-    guard bridged.isValid else {
+  public init?(bridged: swift.SourceLoc) {
+    guard bridged.isValid() else {
       return nil
     }
     self.bridged = bridged
   }
 }
 
-extension SourceLoc {
-  public func advanced(by n: Int) -> SourceLoc {
-    SourceLoc(bridged: bridged.advanced(by: n))!
-  }
-}
-
-extension Optional where Wrapped == SourceLoc {
-  public var bridged: BridgedSourceLoc {
+extension Optional<SourceLoc> {
+  // TODO: This can go back to being 'bridged' once we upgrade to a toolchain
+  // where https://github.com/swiftlang/swift/issues/82609 is fixed.
+  public var bridgedLocation: swift.SourceLoc {
     self?.bridged ?? .init()
   }
 }
@@ -45,7 +44,7 @@ public struct CharSourceRange {
     self.byteLength = byteLength
   }
 
-  public init?(bridgedStart: BridgedSourceLoc, byteLength: UInt32) {
+  public init?(bridgedStart: swift.SourceLoc, byteLength: UInt32) {
     guard let start = SourceLoc(bridged: bridgedStart) else {
       return nil
     }
diff --git a/SwiftCompilerSources/Sources/Basic/Utils.swift b/SwiftCompilerSources/Sources/Basic/Utils.swift
index c68354e06c6b0..cff63254d5a32 100644
--- a/SwiftCompilerSources/Sources/Basic/Utils.swift
+++ b/SwiftCompilerSources/Sources/Basic/Utils.swift
@@ -79,11 +79,15 @@ public extension NoReflectionChildren {
 //                              StringRef
 //===----------------------------------------------------------------------===//
 
-public struct StringRef : CustomStringConvertible, NoReflectionChildren {
+public struct StringRef : CustomStringConvertible, NoReflectionChildren, ExpressibleByStringLiteral {
   public let _bridged: BridgedStringRef
 
   public init(bridged: BridgedStringRef) { self._bridged = bridged }
 
+  public init(stringLiteral: StaticString) {
+    self._bridged = BridgedStringRef(data: stringLiteral.utf8Start, count: stringLiteral.utf8CodeUnitCount)
+  }
+
   public var string: String { String(_bridged)  }
   public var description: String { string }
 
@@ -96,6 +100,20 @@ public struct StringRef : CustomStringConvertible, NoReflectionChildren {
     return buffer[index]
   }
 
+  public func startsWith(_ prefix: StaticString) -> Bool {
+    return prefix.withUTF8Buffer { (prefixBuffer: UnsafeBufferPointer<UInt8>) in
+      if count < prefixBuffer.count {
+        return false
+      }
+      let buffer = UnsafeBufferPointer<UInt8>(start: _bridged.data, count: prefixBuffer.count)
+      return buffer.elementsEqual(prefixBuffer, by: ==)
+    }
+  }
+
+  /// This overload is disfavored to make sure that it's only used for cases that don't involve literals, for that
+  /// `==(StringRef, StaticString) -> Bool` is preferred. Otherwise these overloads are
+  /// going to be ambiguous because both StringRef, StaticString conform to `ExpressibleByStringLiteral`.
+  @_disfavoredOverload
   public static func ==(lhs: StringRef, rhs: StringRef) -> Bool {
     let lhsBuffer = UnsafeBufferPointer<UInt8>(start: lhs._bridged.data, count: lhs.count)
     let rhsBuffer = UnsafeBufferPointer<UInt8>(start: rhs._bridged.data, count: rhs.count)
diff --git a/SwiftCompilerSources/Sources/Optimizer/Analysis/AliasAnalysis.swift b/SwiftCompilerSources/Sources/Optimizer/Analysis/AliasAnalysis.swift
index b238b39087af9..1f74f1d8b93ac 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Analysis/AliasAnalysis.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Analysis/AliasAnalysis.swift
@@ -15,7 +15,7 @@ import SIL
 
 extension FunctionPassContext {
   var aliasAnalysis: AliasAnalysis {
-    let bridgedAA = _bridged.getAliasAnalysis()
+    let bridgedAA = bridgedPassContext.getAliasAnalysis()
     return AliasAnalysis(bridged: bridgedAA, context: self)
   }
 }
@@ -97,8 +97,8 @@ struct AliasAnalysis {
         return false
       }
     }
-    // Finaly use escape info to check if one address "escapes" to the other address.
-    return v1.allContainedAddresss.canAddressAlias(with: v2.allContainedAddresss, context)
+    // Finally use escape info to check if one address "escapes" to the other address.
+    return v1.allContainedAddresses.canAddressAlias(with: v2.allContainedAddresses, context)
   }
 
   static func register() {
@@ -113,7 +113,7 @@ struct AliasAnalysis {
         bridgedAliasAnalysis.mutableCachePointer.assumingMemoryBound(to: Cache.self).deinitialize(count: 1)
       },
       // getMemEffectsFn
-      { (bridgedCtxt: BridgedPassContext,
+      { (bridgedCtxt: BridgedContext,
          bridgedAliasAnalysis: BridgedAliasAnalysis,
          bridgedAddr: BridgedValue,
          bridgedInst: BridgedInstruction) -> BridgedMemoryBehavior in
@@ -121,7 +121,7 @@ struct AliasAnalysis {
         return aa.getMemoryEffect(of: bridgedInst.instruction, on: bridgedAddr.value).bridged
       },
       // isObjReleasedFn
-      { (bridgedCtxt: BridgedPassContext,
+      { (bridgedCtxt: BridgedContext,
          bridgedAliasAnalysis: BridgedAliasAnalysis,
          bridgedObj: BridgedValue,
          bridgedInst: BridgedInstruction) -> Bool in
@@ -142,13 +142,13 @@ struct AliasAnalysis {
       },
 
       // isAddrVisibleFromObj
-      { (bridgedCtxt: BridgedPassContext,
+      { (bridgedCtxt: BridgedContext,
          bridgedAliasAnalysis: BridgedAliasAnalysis,
          bridgedAddr: BridgedValue,
          bridgedObj: BridgedValue) -> Bool in
         let context = FunctionPassContext(_bridged: bridgedCtxt)
         let aa = AliasAnalysis(bridged: bridgedAliasAnalysis, context: context)
-        let addr = bridgedAddr.value.allContainedAddresss
+        let addr = bridgedAddr.value.allContainedAddresses
 
         // This is similar to `canReferenceSameFieldFn`, except that all addresses of all objects are
         // considered which are transitively visible from `bridgedObj`.
@@ -159,7 +159,7 @@ struct AliasAnalysis {
       },
 
       // mayAliasFn
-      { (bridgedCtxt: BridgedPassContext,
+      { (bridgedCtxt: BridgedContext,
          bridgedAliasAnalysis: BridgedAliasAnalysis,
          bridgedLhs: BridgedValue,
          bridgedRhs: BridgedValue) -> Bool in
@@ -253,17 +253,26 @@ struct AliasAnalysis {
     case let storeBorrow as StoreBorrowInst:
       return memLoc.mayAlias(with: storeBorrow.destination, self) ? .init(write: true) : .noEffects
 
-    case let mdi as MarkDependenceInstruction:
+    case let mdi as MarkDependenceInst:
       if mdi.base.type.isAddress && memLoc.mayAlias(with: mdi.base, self) {
         return .init(read: true)
       }
       return .noEffects
 
+    case let mdai as MarkDependenceAddrInst:
+      if memLoc.mayAlias(with: mdai.address, self) {
+        return .init(read: true, write: true)
+      }
+      if mdai.base.type.isAddress && memLoc.mayAlias(with: mdai.base, self) {
+        return .init(read: true)
+      }
+      return .noEffects
+
     case let copy as SourceDestAddrInstruction:
       let mayRead = memLoc.mayAlias(with: copy.source, self)
       let mayWrite = memLoc.mayAlias(with: copy.destination, self)
-      var effects = SideEffects.Memory(read: mayRead, write: mayWrite || (mayRead && copy.isTakeOfSrc))
-      if !copy.isInitializationOfDest {
+      var effects = SideEffects.Memory(read: mayRead, write: mayWrite || (mayRead && copy.isTakeOfSource))
+      if !copy.isInitializationOfDestination {
         effects.merge(with: defaultEffects(of: copy, on: memLoc))
       }
       return effects
@@ -318,7 +327,8 @@ struct AliasAnalysis {
       return defaultEffects(of: endBorrow, on: memLoc)
 
     case let debugValue as DebugValueInst:
-      if debugValue.operand.value.type.isAddress && memLoc.mayAlias(with: debugValue.operand.value, self) {
+      let v = debugValue.operand.value
+      if v.type.isAddress, !(v is Undef), memLoc.mayAlias(with: v, self) {
         return .init(read: true)
       } else {
         return .noEffects
@@ -329,7 +339,7 @@ struct AliasAnalysis {
         return .noEffects
       }
       if destroy.isDeadEnd {
-        // We don't have to take deinit effects into acount for a `destroy_value [dead_end]`.
+        // We don't have to take deinit effects into account for a `destroy_value [dead_end]`.
         // Such destroys are lowered to no-ops and will not call any deinit.
         return .noEffects
       }
@@ -358,7 +368,7 @@ struct AliasAnalysis {
       return defaultEffects(of: endBorrow, on: memLoc)
     case .box, .class, .tail:
       // Check if the memLoc is "derived" from the begin_borrow, i.e. is an interior pointer.
-      var walker = FindBeginBorrowWalker(beginBorrow: endBorrow.borrow as! BorrowIntroducingInstruction)
+      var walker = FindBeginBorrowWalker(beginBorrow: endBorrow.borrow as! BeginBorrowInstruction)
       return walker.visitAccessStorageRoots(of: accessPath) ? .noEffects : .worstEffects
     }
   }
@@ -425,6 +435,11 @@ struct AliasAnalysis {
       }
       let callee = builtin.operands[1].value
       return context.calleeAnalysis.getSideEffects(ofCallee: callee).memory
+    case .PrepareInitialization, .ZeroInitializer:
+      if builtin.arguments.count == 1, memLoc.mayAlias(with: builtin.arguments[0], self) {
+        return .init(write: true)
+      }
+      return .noEffects
     default:
       return defaultEffects(of: builtin, on: memLoc)
     }
@@ -456,7 +471,7 @@ struct AliasAnalysis {
   }
 
   // To avoid quadratic complexity for large functions, we limit the amount of work that the EscapeUtils are
-  // allowed to to. This keeps the complexity linear.
+  // allowed to do. This keeps the complexity linear.
   //
   // This arbitrary limit is good enough for almost all functions. It lets
   // the EscapeUtils do several hundred up/down walks which is much more than needed in most cases.
@@ -466,14 +481,14 @@ struct AliasAnalysis {
       for _ in function.instructions { numInsts += 1 }
       cache.estimatedFunctionSize = numInsts
     }
-    return 1000000 / cache.estimatedFunctionSize!
+    return 1_000_000 / cache.estimatedFunctionSize!
   }
 
   /// Returns true if the `instruction` (which in general writes to memory) is immutable in a certain scope,
   /// defined by `address`.
   ///
   /// That means that even if we don't know anything about `instruction`, we can be sure
-  /// that `instruction` cannot write to `address`, if it's inside the addresse's scope.
+  /// that `instruction` cannot write to `address`, if it's inside the address's scope.
   /// An immutable scope is for example a read-only `begin_access`/`end_access` scope.
   /// Another example is a borrow scope of an immutable copy-on-write buffer.
   private func isImmutable(instruction: Instruction, inScopeOf address: Value) -> Bool {
@@ -613,6 +628,14 @@ private enum ImmutableScope {
       if beginAccess.isUnsafe {
         return nil
       }
+
+      // This is a workaround for a bug in the move-only checker: rdar://151841926.
+      // The move-only checker sometimes inserts destroy_addr within read-only static access scopes.
+      // TODO: remove this once the bug is fixed.
+      if beginAccess.isStatic {
+        return nil
+      }
+
       switch beginAccess.accessKind {
       case .read:
         self = .readAccess(beginAccess)
@@ -704,7 +727,7 @@ private enum ImmutableScope {
 }
 
 private struct FindBeginBorrowWalker : ValueUseDefWalker {
-  let beginBorrow: BorrowIntroducingInstruction
+  let beginBorrow: BeginBorrowInstruction
   var walkUpCache = WalkerCache<Path>()
 
   mutating func walkUp(value: Value, path: SmallProjectionPath) -> WalkResult {
@@ -774,7 +797,7 @@ private struct FullApplyEffectsVisitor : EscapeVisitorWithResult {
 
 // In contrast to a full apply, the effects of a partial_apply don't depend on the callee
 // (a partial_apply doesn't call anything, it just creates a thick function pointer).
-// The only effects come from capturing the arguments (either consuming or guaranteeed).
+// The only effects come from capturing the arguments (either consuming or guaranteed).
 private struct PartialApplyEffectsVisitor : EscapeVisitorWithResult {
   let partialApply: PartialApplyInst
   var result = SideEffects.Memory.noEffects
diff --git a/SwiftCompilerSources/Sources/Optimizer/Analysis/CMakeLists.txt b/SwiftCompilerSources/Sources/Optimizer/Analysis/CMakeLists.txt
index bedf3296a61df..4f95a146351ba 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Analysis/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/Optimizer/Analysis/CMakeLists.txt
@@ -9,6 +9,7 @@
 swift_compiler_sources(Optimizer
   AliasAnalysis.swift
   CalleeAnalysis.swift
+  LoopTree.swift
   DeadEndBlocksAnalysis.swift
   DominatorTree.swift
   PostDominatorTree.swift)
diff --git a/SwiftCompilerSources/Sources/Optimizer/Analysis/DominatorTree.swift b/SwiftCompilerSources/Sources/Optimizer/Analysis/DominatorTree.swift
index c7c106d879c08..132434c5eb028 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Analysis/DominatorTree.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Analysis/DominatorTree.swift
@@ -15,6 +15,31 @@ import OptimizerBridging
 
 struct DominatorTree {
   let bridged: BridgedDomTree
+  
+  func getChildren(of block: BasicBlock) -> DomChildren {
+    return DomChildren(bridgedDomTree: bridged, bb: block)
+  }
+}
+
+struct DomChildren: BridgedRandomAccessCollection {
+  private let bridgedDomTree: BridgedDomTree
+  private let block: BasicBlock
+  
+  let count: Int
+  
+  var startIndex: Int { return 0 }
+  var endIndex: Int { return count }
+  
+  init(bridgedDomTree: BridgedDomTree, bb: BasicBlock) {
+    self.bridgedDomTree = bridgedDomTree
+    self.block = bb
+    self.count = bridgedDomTree.getNumberOfChildren(bb.bridged)
+  }
+  
+  subscript(_ index: Int) -> BasicBlock {
+    assert(index >= startIndex && index < endIndex)
+    return bridgedDomTree.getChildAt(block.bridged, index).block
+  }
 }
 
 extension BasicBlock {
diff --git a/SwiftCompilerSources/Sources/Optimizer/Analysis/LoopTree.swift b/SwiftCompilerSources/Sources/Optimizer/Analysis/LoopTree.swift
new file mode 100644
index 0000000000000..aab4605926c3b
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/Analysis/LoopTree.swift
@@ -0,0 +1,213 @@
+//===--- LoopTree.swift ---------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+import OptimizerBridging
+
+/// Describes top level loops.
+struct LoopTree {
+  fileprivate let bridged: BridgedLoopTree
+  
+  let loops: TopLevelLoopArray
+  
+  init(bridged: BridgedLoopTree, context: FunctionPassContext) {
+    self.bridged = bridged
+    self.loops = TopLevelLoopArray(bridged)
+  }
+}
+
+/// Describes a loop with its children.
+struct Loop {
+  private let bridged: BridgedLoop
+  
+  let innerLoops: LoopArray
+  let loopBlocks: LoopBlocks
+  
+  var exitingAndLatchBlocks: some Sequence<BasicBlock> {
+    return header.predecessors.lazy
+      .filter { predecessor in
+        contains(block: predecessor) && !isLoopExiting(loopBlock: predecessor)
+      } + exitingBlocks
+  }
+  
+  /// Exit blocks of the loop.
+  ///
+  /// - Note: Some exit blocks will be duplicated if the loop has critical edges.
+  var exitBlocks: some Sequence<BasicBlock> {
+    return loopBlocks.lazy
+      .flatMap(\.successors)
+      .filter { !contains(block: $0) }
+  }
+  
+  var exitingBlocks: some Sequence<BasicBlock> {
+    return loopBlocks.lazy
+      .filter { isLoopExiting(loopBlock: $0) }
+  }
+  
+  init(bridged: BridgedLoop) {
+    self.bridged = bridged
+    self.innerLoops = LoopArray(bridged)
+    self.loopBlocks = LoopBlocks(bridged)
+  }
+  
+  var preheader: BasicBlock? {
+    bridged.getPreheader().block
+  }
+  
+  var header: BasicBlock {
+    bridged.getHeader().block
+  }
+  
+  /// Returns `true` if the loop has exactly one exit block.
+  var hasSingleExitBlock: Bool {
+    return exitBlocks.singleElement != nil
+  }
+  
+  var hasNoExitBlocks: Bool {
+    return exitBlocks.isEmpty
+  }
+  
+  private func isLoopExiting(loopBlock: BasicBlock) -> Bool {
+    return loopBlock.successors.contains { !contains(block: $0) }
+  }
+  
+  func getBlocksThatDominateAllExitingAndLatchBlocks(_ context: FunctionPassContext) -> [BasicBlock] {
+    var result: [BasicBlock] = []
+    var cachedExitingAndLatchBlocks = Stack<BasicBlock>(context)
+    var workList = BasicBlockWorklist(context)
+    defer {
+      cachedExitingAndLatchBlocks.deinitialize()
+      workList.deinitialize()
+    }
+    
+    cachedExitingAndLatchBlocks.append(contentsOf: exitingAndLatchBlocks)
+    workList.pushIfNotVisited(header)
+    
+    while let block = workList.pop() {
+      guard cachedExitingAndLatchBlocks.allSatisfy({ exitBlock in
+        return block.dominates(exitBlock, context.dominatorTree)
+      }) else {
+        continue
+      }
+      
+      result.append(block)
+      
+      workList.pushIfNotVisited(contentsOf: context.dominatorTree.getChildren(of: block))
+    }
+    
+    return result
+  }
+  
+  func contains(block: BasicBlock) -> Bool {
+    return bridged.contains(block.bridged)
+  }
+  
+  func splitCriticalExitingAndBackEdges(_ context: FunctionPassContext) {
+    for exitingOrLatchBlock in exitingAndLatchBlocks {
+      for (index, succesor) in exitingOrLatchBlock.successors.enumerated() where !contains(block: succesor) {
+        splitCriticalEdge(
+          from: exitingOrLatchBlock.terminator.parentBlock,
+          toEdgeIndex: index,
+          dominatorTree: context.dominatorTree,
+          loopTree: context.loopTree,
+          context
+        )
+      }
+    }
+  }
+}
+
+struct TopLevelLoopArray: BridgedRandomAccessCollection {
+  private let bridgedLoopTree: BridgedLoopTree
+  
+  let count: Int
+  
+  var startIndex: Int { return 0 }
+  var endIndex: Int { return count }
+  
+  init(_ bridgedLoopTree: BridgedLoopTree) {
+    self.bridgedLoopTree = bridgedLoopTree
+    self.count = bridgedLoopTree.getTopLevelLoopCount()
+  }
+  
+  subscript(_ index: Int) -> Loop {
+    assert(index >= startIndex && index < endIndex)
+    return Loop(bridged: bridgedLoopTree.getLoop(index))
+  }
+}
+
+struct LoopArray: BridgedRandomAccessCollection {
+  private let bridgedLoop: BridgedLoop
+  
+  let count: Int
+  
+  var startIndex: Int { return 0 }
+  var endIndex: Int { return count }
+  
+  init(_ bridgedLoop: BridgedLoop) {
+    self.bridgedLoop = bridgedLoop
+    self.count = bridgedLoop.getInnerLoopCount()
+  }
+  
+  subscript(_ index: Int) -> Loop {
+    assert(index >= startIndex && index < endIndex)
+    return Loop(bridged: bridgedLoop.getInnerLoop(index))
+  }
+}
+
+struct LoopBlocks: BridgedRandomAccessCollection {
+  private let bridgedLoop: BridgedLoop
+  
+  let count: Int
+  
+  var startIndex: Int { return 0 }
+  var endIndex: Int { return count }
+  
+  init(_ bridgedLoop: BridgedLoop) {
+    self.bridgedLoop = bridgedLoop
+    self.count = bridgedLoop.getBasicBlockCount()
+  }
+  
+  subscript(_ index: Int) -> BasicBlock {
+    assert(index >= startIndex && index < endIndex)
+    return bridgedLoop.getBasicBlock(index).block
+  }
+}
+
+func splitEdge(
+  from block: BasicBlock,
+  toEdgeIndex: Int,
+  dominatorTree: DominatorTree,
+  loopTree: LoopTree,
+  _ context: some MutatingContext
+) -> BasicBlock {
+  let result = loopTree.bridged.splitEdge(block.bridged, toEdgeIndex, dominatorTree.bridged).block
+  
+  context.notifyBranchesChanged()
+  return result
+}
+
+/// If the specified edge is critical, the function returns inserted block. Otherwise returns `nil`.
+@discardableResult
+func splitCriticalEdge(
+  from block: BasicBlock,
+  toEdgeIndex: Int,
+  dominatorTree: DominatorTree,
+  loopTree: LoopTree,
+  _ context: some MutatingContext
+) -> BasicBlock? {
+  guard block.isCriticalEdge(edgeIndex: toEdgeIndex) else {
+    return nil
+  }
+  
+  return splitEdge(from: block, toEdgeIndex: toEdgeIndex, dominatorTree: dominatorTree, loopTree: loopTree, context)
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/DataStructures/CMakeLists.txt b/SwiftCompilerSources/Sources/Optimizer/DataStructures/CMakeLists.txt
index 9cda577b95a84..f5e7afa317c82 100644
--- a/SwiftCompilerSources/Sources/Optimizer/DataStructures/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/Optimizer/DataStructures/CMakeLists.txt
@@ -7,11 +7,6 @@
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 swift_compiler_sources(Optimizer
-  BasicBlockRange.swift
   DeadEndBlocks.swift
   FunctionUses.swift
-  InstructionRange.swift
-  ReachableBlocks.swift
-  Set.swift
-  Stack.swift
-  Worklist.swift)
+  ReachableBlocks.swift)
diff --git a/SwiftCompilerSources/Sources/Optimizer/DataStructures/InstructionRange.swift b/SwiftCompilerSources/Sources/Optimizer/DataStructures/InstructionRange.swift
deleted file mode 100644
index 13fdedd4d18a6..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/DataStructures/InstructionRange.swift
+++ /dev/null
@@ -1,183 +0,0 @@
-//===--- InstructionRange.swift - a range of instructions -----------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import SIL
-
-/// A range of instructions.
-///
-/// The `InstructionRange` defines a range from a dominating "begin" instruction to one or more "end" instructions.
-/// The range is "exclusive", which means that the "end" instructions are not part of the range.
-///
-/// One or more "potential" end instructions can be inserted.
-/// Though, not all inserted instructions end up as "end" instructions.
-///
-/// `InstructionRange` is useful for calculating the liverange of values.
-///
-/// The `InstructionRange` is similar to a `BasicBlockRange`, but defines the range
-/// in a "finer" granularity, i.e. on instructions instead of blocks.
-/// `InstructionRange` uses an underlying `BasicBlockRange` to compute the
-/// involved blocks of the instruction range.
-///
-/// There are several kind of instructions:
-/// * begin: it is a single instruction which dominates all instructions of the range
-/// * ends: all inserted instruction which are at the end of the range
-/// * exits: the first instructions of the exit blocks
-/// * interiors: all inserted instructions which are not end instructions.
-///
-/// See also `BasicBlockRange` for more information.
-///
-/// This type should be a move-only type, but unfortunately we don't have move-only
-/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
-/// destruct this data structure, e.g. in a `defer {}` block.
-struct InstructionRange : CustomStringConvertible, NoReflectionChildren {
-  
-  /// The underlying block range.
-  private(set) var blockRange: BasicBlockRange
-
-  private var insertedInsts: InstructionSet
-
-  // For efficiency, this set does not include instructions in blocks which are not the begin or any end block.
-  private var inExclusiveRange: InstructionSet
-
-  init(begin beginInst: Instruction, _ context: some Context) {
-    self = InstructionRange(beginBlock: beginInst.parentBlock, context)
-    self.inExclusiveRange.insert(beginInst)
-  }
-
-  // Note: 'ends' are simply the instructions to insert in the range. 'self.ends' might not return the same sequence
-  // as this 'ends' argument because 'self.ends' will not include block exits.
-  init<S: Sequence>(begin beginInst: Instruction, ends: S, _ context: some Context) where S.Element: Instruction {
-    self = InstructionRange(begin: beginInst, context)
-    insert(contentsOf: ends)
-  }
-
-  init(for value: Value, _ context: some Context) {
-    if let inst = value.definingInstruction {
-      self = InstructionRange(begin: inst, context)
-    } else if let arg = value as? Argument {
-      self = InstructionRange(beginBlock: arg.parentBlock, context)
-    } else {
-      fatalError("cannot build an instruction range for \(value)")
-    }
-  }
-
-  private init(beginBlock: BasicBlock, _ context: some Context) {
-    self.blockRange = BasicBlockRange(begin: beginBlock, context)
-    self.insertedInsts = InstructionSet(context)
-    self.inExclusiveRange = InstructionSet(context)
-  }
-
-  /// Insert a potential end instruction.
-  mutating func insert(_ inst: Instruction) {
-    insertedInsts.insert(inst)
-    insertIntoRange(instructions: ReverseInstructionList(first: inst.previous))
-    blockRange.insert(inst.parentBlock)
-    if inst.parentBlock != blockRange.begin {
-      // The first time an instruction is inserted in another block than the begin-block we need to insert
-      // instructions from the begin instruction to the end of the begin block.
-      // For subsequent insertions this is a no-op: `insertIntoRange` will return immediately because those
-      // instruction are already inserted.
-      insertIntoRange(instructions: blockRange.begin.instructions.reversed())
-    }
-  }
-
-  /// Insert a sequence of potential end instructions.
-  mutating func insert<S: Sequence>(contentsOf other: S) where S.Element: Instruction {
-    for inst in other {
-      insert(inst)
-    }
-  }
-
-  /// Returns true if the exclusive range contains `inst`.
-  func contains(_ inst: Instruction) -> Bool {
-    if inExclusiveRange.contains(inst) {
-      return true
-    }
-    let block = inst.parentBlock
-    return block != blockRange.begin && blockRange.contains(block)
-  }
-
-  /// Returns true if the inclusive range contains `inst`.
-  func inclusiveRangeContains (_ inst: Instruction) -> Bool {
-    contains(inst) || insertedInsts.contains(inst)
-  }
-
-  /// Returns the end instructions.
-  ///
-  /// Warning: this returns `begin` if no instructions were inserted.
-  var ends: LazyMapSequence<LazyFilterSequence<Stack<BasicBlock>>, Instruction> {
-    blockRange.ends.map {
-      $0.instructions.reversed().first(where: { insertedInsts.contains($0)})!
-    }
-  }
-
-  // Returns the exit blocks.
-  var exitBlocks: LazySequence<FlattenSequence<
-                    LazyMapSequence<LazyFilterSequence<Stack<BasicBlock>>,
-                                    LazyFilterSequence<SuccessorArray>>>> {
-    blockRange.exits
-  }
-
-  /// Returns the exit instructions.
-  var exits: LazyMapSequence<LazySequence<FlattenSequence<
-                               LazyMapSequence<LazyFilterSequence<Stack<BasicBlock>>,
-                                               LazyFilterSequence<SuccessorArray>>>>,
-                             Instruction> {
-    blockRange.exits.lazy.map { $0.instructions.first! }
-  }
-
-  /// Returns the interior instructions.
-  var interiors: LazySequence<FlattenSequence<
-                   LazyMapSequence<Stack<BasicBlock>,
-                                   LazyFilterSequence<ReverseInstructionList>>>> {
-    blockRange.inserted.lazy.flatMap {
-      var include = blockRange.contains($0)
-      return $0.instructions.reversed().lazy.filter {
-        if insertedInsts.contains($0) {
-          let isInterior = include
-          include = true
-          return isInterior
-        }
-        return false
-      }
-    }
-  }
-
-  var begin: Instruction? {
-    blockRange.begin.instructions.first(where: inExclusiveRange.contains)
-  }
-
-  private mutating func insertIntoRange(instructions: ReverseInstructionList) {
-    for inst in instructions {
-      if !inExclusiveRange.insert(inst) {
-        return
-      }
-    }
-  }
-
-  var description: String {
-    return (blockRange.isValid ? "" : "<invalid>\n") +
-      """
-      begin:    \(begin?.description ?? blockRange.begin.name)
-      ends:     \(ends.map { $0.description }.joined(separator: "\n          "))
-      exits:    \(exits.map { $0.description }.joined(separator: "\n          "))
-      interiors:\(interiors.map { $0.description }.joined(separator: "\n          "))
-      """
-  }
-
-  /// TODO: once we have move-only types, make this a real deinit.
-  mutating func deinitialize() {
-    inExclusiveRange.deinitialize()
-    insertedInsts.deinitialize()
-    blockRange.deinitialize()
-  }
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/DataStructures/Set.swift b/SwiftCompilerSources/Sources/Optimizer/DataStructures/Set.swift
deleted file mode 100644
index 2b95ad273cb4e..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/DataStructures/Set.swift
+++ /dev/null
@@ -1,245 +0,0 @@
-//===--- Set.swift - sets for basic blocks, values and instructions -------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import SIL
-import OptimizerBridging
-
-protocol IntrusiveSet : CustomStringConvertible, NoReflectionChildren {
-  associatedtype Element
-
-  init(_ context: some Context)
-  mutating func insert(_ element: Element) -> Bool
-  mutating func erase(_ element: Element)
-  func contains(_ element: Element) -> Bool
-  mutating func deinitialize()
-}
-
-/// A set of basic blocks.
-///
-/// This is an extremely efficient implementation which does not need memory
-/// allocations or hash lookups.
-///
-/// This type should be a move-only type, but unfortunately we don't have move-only
-/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
-/// destruct this data structure, e.g. in a `defer {}` block.
-struct BasicBlockSet : IntrusiveSet {
-
-  private let context: BridgedPassContext
-  private let bridged: BridgedBasicBlockSet
-    
-  init(_ context: some Context) {
-    self.context = context._bridged
-    self.bridged = self.context.allocBasicBlockSet()
-  }
-
-  func contains(_ block: BasicBlock) -> Bool {
-    bridged.contains(block.bridged)
-  }
-
-  /// Returns true if `block` was not contained in the set before inserting.
-  @discardableResult
-  mutating func insert(_ block: BasicBlock) -> Bool {
-    bridged.insert(block.bridged)
-  }
-
-  mutating func erase(_ block: BasicBlock) {
-    bridged.erase(block.bridged)
-  }
-
-  var description: String {
-    let function = bridged.getFunction().function
-    let blockNames = function.blocks.enumerated().filter { contains($0.1) }
-                                                 .map { "bb\($0.0)"}
-    return "{" + blockNames.joined(separator: ", ") + "}"
-  }
-
-  /// TODO: once we have move-only types, make this a real deinit.
-  mutating func deinitialize() {
-    context.freeBasicBlockSet(bridged)
-  }
-}
-
-/// A set of values.
-///
-/// This is an extremely efficient implementation which does not need memory
-/// allocations or hash lookups.
-///
-/// This type should be a move-only type, but unfortunately we don't have move-only
-/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
-/// destruct this data structure, e.g. in a `defer {}` block.
-struct ValueSet : IntrusiveSet {
-
-  private let context: BridgedPassContext
-  private let bridged: BridgedNodeSet
-    
-  init(_ context: some Context) {
-    self.context = context._bridged
-    self.bridged = self.context.allocNodeSet()
-  }
-
-  func contains(_ value: Value) -> Bool {
-    bridged.containsValue(value.bridged)
-  }
-
-  /// Returns true if `value` was not contained in the set before inserting.
-  @discardableResult
-  mutating func insert(_ value: Value) -> Bool {
-    bridged.insertValue(value.bridged)
-  }
-
-  mutating func erase(_ value: Value) {
-    bridged.eraseValue(value.bridged)
-  }
-
-  var description: String {
-    let function = bridged.getFunction().function
-    var d = "{\n"
-    for block in function.blocks {
-      for arg in block.arguments {
-        if contains(arg) {
-          d += arg.description
-        }
-      }
-      for inst in block.instructions {
-        for result in inst.results {
-          if contains(result) {
-            d += result.description
-          }
-        }
-      }
-    }
-    d += "}\n"
-    return d
-  }
-
-  /// TODO: once we have move-only types, make this a real deinit.
-  mutating func deinitialize() {
-    context.freeNodeSet(bridged)
-  }
-}
-
-/// A set of instructions.
-///
-/// This is an extremely efficient implementation which does not need memory
-/// allocations or hash lookups.
-///
-/// This type should be a move-only type, but unfortunately we don't have move-only
-/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
-/// destruct this data structure, e.g. in a `defer {}` block.
-struct SpecificInstructionSet<InstType: Instruction> : IntrusiveSet {
-
-  private let context: BridgedPassContext
-  private let bridged: BridgedNodeSet
-    
-  init(_ context: some Context) {
-    self.context = context._bridged
-    self.bridged = self.context.allocNodeSet()
-  }
-
-  func contains(_ inst: InstType) -> Bool {
-    bridged.containsInstruction(inst.bridged)
-  }
-
-  /// Returns true if `inst` was not contained in the set before inserting.
-  @discardableResult
-  mutating func insert(_ inst: InstType) -> Bool {
-    bridged.insertInstruction(inst.bridged)
-  }
-
-  mutating func erase(_ inst: InstType) {
-    bridged.eraseInstruction(inst.bridged)
-  }
-
-  var description: String {
-    let function = bridged.getFunction().function
-    var d = "{\n"
-    for i in function.instructions {
-      if let inst = i as? InstType, contains(inst) {
-        d += inst.description + "\n"
-      }
-    }
-    d += "}\n"
-    return d
-  }
-
-  /// TODO: once we have move-only types, make this a real deinit.
-  mutating func deinitialize() {
-    context.freeNodeSet(bridged)
-  }
-}
-
-typealias InstructionSet = SpecificInstructionSet<Instruction>
-
-/// A set of operands.
-///
-/// This is an extremely efficient implementation which does not need memory
-/// allocations or hash lookups.
-///
-/// This type should be a move-only type, but unfortunately we don't have move-only
-/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
-/// destruct this data structure, e.g. in a `defer {}` block.
-struct OperandSet : IntrusiveSet {
-
-  private let context: BridgedPassContext
-  private let bridged: BridgedOperandSet
-
-  init(_ context: some Context) {
-    self.context = context._bridged
-    self.bridged = self.context.allocOperandSet()
-  }
-
-  func contains(_ operand: Operand) -> Bool {
-    bridged.contains(operand.bridged)
-  }
-
-  /// Returns true if `inst` was not contained in the set before inserting.
-  @discardableResult
-  mutating func insert(_ operand: Operand) -> Bool {
-    bridged.insert(operand.bridged)
-  }
-
-  mutating func erase(_ operand: Operand) {
-    bridged.erase(operand.bridged)
-  }
-
-  var description: String {
-    let function = bridged.getFunction().function
-    var d = "{\n"
-    for inst in function.instructions {
-      for op in inst.operands {
-        if contains(op) {
-          d += op.description
-        }
-      }
-    }
-    d += "}\n"
-    return d
-  }
-
-  /// TODO: once we have move-only types, make this a real deinit.
-  mutating func deinitialize() {
-    context.freeOperandSet(bridged)
-  }
-}
-
-extension IntrusiveSet {
-  mutating func insert(contentsOf source: some Sequence<Element>) {
-    for element in source {
-      _ = insert(element)
-    }
-  }
-
-  init(insertContentsOf source: some Sequence<Element>, _ context: some Context) {
-    self.init(context)
-    insert(contentsOf: source)
-  }
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/DataStructures/Stack.swift b/SwiftCompilerSources/Sources/Optimizer/DataStructures/Stack.swift
deleted file mode 100644
index c38e8da5404f5..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/DataStructures/Stack.swift
+++ /dev/null
@@ -1,222 +0,0 @@
-//===--- Stack.swift - defines the Stack data structure -------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import OptimizerBridging
-import SIL
-
-/// A very efficient implementation of a stack, which can also be iterated over.
-///
-/// A Stack is the best choice for things like worklists, etc., if no random
-/// access is needed.
-/// Compared to Array, it does not require any memory allocations, because it
-/// uses a recycling bump pointer allocator for allocating the slabs.
-/// All operations have (almost) zero cost.
-///
-/// This type should be a move-only type, but unfortunately we don't have move-only
-/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
-/// destruct this data structure, e.g. in a `defer {}` block.
-struct Stack<Element> : CollectionLikeSequence {
-
-  private let bridgedContext: BridgedPassContext
-  private var firstSlab = BridgedPassContext.Slab(nil)
-  private var lastSlab = BridgedPassContext.Slab(nil)
-  private var endIndex: Int = 0
-
-  private static var slabCapacity: Int {
-    BridgedPassContext.Slab.getCapacity() / MemoryLayout<Element>.stride
-  }
-
-  private func allocate(after lastSlab: BridgedPassContext.Slab? = nil) -> BridgedPassContext.Slab {
-    let lastSlab = lastSlab ?? BridgedPassContext.Slab(nil)
-    let newSlab = bridgedContext.allocSlab(lastSlab)
-    UnsafeMutableRawPointer(newSlab.data!).bindMemory(to: Element.self, capacity: Stack.slabCapacity)
-    return newSlab
-  }
-
-  private static func element(in slab: BridgedPassContext.Slab, at index: Int) -> Element {
-    return pointer(in: slab, at: index).pointee
-  }
-
-  private static func pointer(in slab: BridgedPassContext.Slab, at index: Int) -> UnsafeMutablePointer<Element> {
-    return UnsafeMutableRawPointer(slab.data!).assumingMemoryBound(to: Element.self) + index
-  }
-
-  struct Iterator : IteratorProtocol {
-    var slab: BridgedPassContext.Slab
-    var index: Int
-    let lastSlab: BridgedPassContext.Slab
-    let endIndex: Int
-    
-    mutating func next() -> Element? {
-      let end = (slab.data == lastSlab.data ? endIndex : slabCapacity)
-      
-      guard index < end else { return nil }
-    
-      let elem = Stack.element(in: slab, at: index)
-      index += 1
-      
-      if index >= end && slab.data != lastSlab.data {
-        slab = slab.getNext()
-        index = 0
-      }
-      return elem
-    }
-  }
-  
-  init(_ context: some Context) { self.bridgedContext = context._bridged }
-
-  func makeIterator() -> Iterator {
-    return Iterator(slab: firstSlab, index: 0, lastSlab: lastSlab, endIndex: endIndex)
-  }
-
-  var first: Element? {
-    isEmpty ? nil : Stack.element(in: firstSlab, at: 0)
-  }
-
-  var last: Element? {
-    isEmpty ? nil : Stack.element(in: lastSlab, at: endIndex &- 1)
-  }
-
-  mutating func push(_ element: Element) {
-    if endIndex >= Stack.slabCapacity {
-      lastSlab = allocate(after: lastSlab)
-      endIndex = 0
-    } else if firstSlab.data == nil {
-      assert(endIndex == 0)
-      firstSlab = allocate()
-      lastSlab = firstSlab
-    }
-    Stack.pointer(in: lastSlab, at: endIndex).initialize(to: element)
-    endIndex += 1
-  }
-
-  /// The same as `push` to provide an Array-like append API.
-  mutating func append(_ element: Element) { push(element) }
-
-  mutating func append<S: Sequence>(contentsOf other: S) where S.Element == Element {
-    for elem in other {
-      append(elem)
-    }
-  }
-
-  var isEmpty: Bool { return endIndex == 0 }
-  
-  mutating func pop() -> Element? {
-    if isEmpty {
-      return nil
-    }
-    assert(endIndex > 0)
-    endIndex -= 1
-    let elem = Stack.pointer(in: lastSlab, at: endIndex).move()
-    
-    if endIndex == 0 {
-      if lastSlab.data == firstSlab.data {
-        _ = bridgedContext.freeSlab(lastSlab)
-        firstSlab.data = nil
-        lastSlab.data = nil
-        endIndex = 0
-      } else {
-        lastSlab = bridgedContext.freeSlab(lastSlab)
-        endIndex = Stack.slabCapacity
-      }
-    }
-
-    return elem
-  }
-  
-  mutating func removeAll() {
-    while pop() != nil { }
-  }
-
-  /// TODO: once we have move-only types, make this a real deinit.
-  mutating func deinitialize() { removeAll() }
-}
-
-extension Stack {
-  /// Mark a stack location for future iteration.
-  ///
-  /// TODO: Marker should be ~Escapable.
-  struct Marker {
-    let slab: BridgedPassContext.Slab
-    let index: Int
-  }
-
-  var top: Marker { Marker(slab: lastSlab, index: endIndex) }
-
-  struct Segment : CollectionLikeSequence {
-    let low: Marker
-    let high: Marker
-
-    init(in stack: Stack, low: Marker, high: Marker) {
-      if low.slab.data == nil {
-        assert(low.index == 0, "invalid empty stack marker")
-        // `low == nil` and `high == nil` is a valid empty segment,
-        // even though `assertValid(marker:)` would return false.
-        if high.slab.data != nil {
-          stack.assertValid(marker: high)
-        }
-        self.low = Marker(slab: stack.firstSlab, index: 0)
-        self.high = high
-        return
-      }
-      stack.assertValid(marker: low)
-      stack.assertValid(marker: high)
-      self.low = low
-      self.high = high
-    }
-
-    func makeIterator() -> Stack.Iterator {
-      return Iterator(slab: low.slab, index: low.index,
-                      lastSlab: high.slab, endIndex: high.index)
-    }
-  }
-
-  /// Assert that `marker` is valid based on the current `top`.
-  ///
-  /// This is an assert rather than a query because slabs can reuse
-  /// memory leading to a stale marker that appears valid.
-  func assertValid(marker: Marker) {
-    var currentSlab = lastSlab
-    var currentIndex = endIndex
-    while currentSlab.data != marker.slab.data {
-      assert(currentSlab.data != firstSlab.data, "Invalid stack marker")
-      currentSlab = currentSlab.getPrevious()
-      currentIndex = Stack.slabCapacity
-    }
-    assert(marker.index <= currentIndex, "Invalid stack marker")
-  }
-
-  /// Execute the `body` closure, passing it `self` for further
-  /// mutation of the stack and passing `marker` to mark the stack
-  /// position prior to executing `body`. `marker` must not escape the
-  /// `body` closure.
-  mutating func withMarker<R>(
-    _ body: (inout Stack<Element>, Marker) throws -> R) rethrows -> R {
-    return try body(&self, top)
-  }
-
-  /// Record a stack marker, execute a `body` closure, then execute a
-  /// `handleNewElements` closure with the Segment that contains all
-  /// elements that remain on the stack after being pushed on the
-  /// stack while executing `body`. `body` must push more elements
-  /// than it pops.
-  mutating func withMarker<R>(
-    pushElements body: (inout Stack) throws -> R,
-    withNewElements handleNewElements: ((Segment) -> ())
-  ) rethrows -> R {
-    return try withMarker { (stack: inout Stack<Element>, marker: Marker) in
-      let result = try body(&stack)
-      handleNewElements(Segment(in: stack, low: marker, high: stack.top))
-      return result
-    }
-  }
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/DataStructures/Worklist.swift b/SwiftCompilerSources/Sources/Optimizer/DataStructures/Worklist.swift
deleted file mode 100644
index ec1336b064d3d..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/DataStructures/Worklist.swift
+++ /dev/null
@@ -1,97 +0,0 @@
-//===--- Worklist.swift ---------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import SIL
-
-/// A utility for processing entities in a worklist.
-///
-/// A `Worklist` is basically a combination of a stack and a set.
-/// It can be used for typical worklist-processing algorithms.
-///
-/// This type should be a move-only type, but unfortunately we don't have move-only
-/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
-/// destruct this data structure, e.g. in a `defer {}` block.
-struct Worklist<Set: IntrusiveSet> : CustomStringConvertible, NoReflectionChildren {
-  typealias Element = Set.Element
-  private var worklist: Stack<Element>
-  private var pushedElements: Set
-
-  init(_ context: some Context) {
-    self.worklist = Stack(context)
-    self.pushedElements = Set(context)
-  }
-  
-  mutating func pop() -> Element? { return worklist.pop() }
-
-  /// Pop and allow the popped element to be pushed again to the worklist.
-  mutating func popAndForget() -> Element? {
-    if let element = worklist.pop() {
-      pushedElements.erase(element)
-      return element
-    }
-    return nil
-  }
-
-  mutating func pushIfNotVisited(_ element: Element) {
-    if pushedElements.insert(element) {
-      worklist.append(element)
-    }
-  }
-
-  mutating func pushIfNotVisited<S: Sequence>(contentsOf other: S) where S.Element == Element {
-    for element in other {
-      pushIfNotVisited(element)
-    }
-  }
-
-  /// Returns true if \p element was pushed to the worklist, regardless if it's already popped or not.
-  func hasBeenPushed(_ element: Element) -> Bool { pushedElements.contains(element) }
-
-  var isEmpty: Bool { worklist.isEmpty }
-
-  var description: String {
-    """
-    worklist: \(worklist)
-    pushed:   \(pushedElements)
-    """
-  }
-
-  /// TODO: once we have move-only types, make this a real deinit.
-  mutating func deinitialize() {
-    pushedElements.deinitialize()
-    worklist.deinitialize()
-  }
-}
-
-typealias BasicBlockWorklist = Worklist<BasicBlockSet>
-typealias InstructionWorklist = Worklist<InstructionSet>
-typealias SpecificInstructionWorklist<InstType: Instruction> = Worklist<SpecificInstructionSet<InstType>>
-typealias ValueWorklist = Worklist<ValueSet>
-typealias OperandWorklist = Worklist<OperandSet>
-
-extension InstructionWorklist {
-  mutating func pushPredecessors(of inst: Instruction, ignoring ignoreInst: Instruction) {
-    if let prev = inst.previous {
-      if prev != ignoreInst {
-        pushIfNotVisited(prev)
-      }
-    } else {
-      for predBlock in inst.parentBlock.predecessors {
-        let termInst = predBlock.terminator
-        if termInst != ignoreInst {
-          pushIfNotVisited(termInst)
-        }
-      }
-    }
-  }
-}
-
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/AllocBoxToStack.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/AllocBoxToStack.swift
new file mode 100644
index 0000000000000..6956c1078ec8d
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/AllocBoxToStack.swift
@@ -0,0 +1,516 @@
+//===--- AllocBoxToStack.swift --------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+
+/// Replaces `alloc_box` with `alloc_stack` if the box is not escaping.
+///
+/// ```
+///   %1 = alloc_box  ${ var T }
+///   %2 = project_box %1, 0
+///   ...
+///   store %3 to %2              // uses of the box field
+///   ...
+///   destroy_value %1            // end of lifetime of the box
+/// ```
+/// ->
+/// ```
+///   %2 = alloc_stack $T
+///   ...
+///   store %3 to %2              // uses of the stack location
+///   ...
+///   destroy_addr %2             // end of lifetime
+///   dealloc_stack %2
+/// ```
+///
+/// This transformation also works inter-procedurally. If the box is passed to a callee,
+/// the callee is specialized: instead of the box argument the stack address is passed
+/// as `@inout_aliasable` parameter:
+///
+/// ```
+///   sil @closure : $(@guaranteed var { T }) -> () {
+///   bb0(%0 : @guaranteed ${ var T }):
+///     %1 = project_box %0
+///     %2 = load %1
+///     ...
+/// ```
+/// ->
+/// ```
+///   sil @specialized_closure : $(@inout_aliasable T) -> () {
+///   bb0(%0 : $*T):
+///     %2 = load %0
+///     ...
+/// ```
+///
+let allocBoxToStack = FunctionPass(name: "allocbox-to-stack") {
+  (function: Function, context: FunctionPassContext) in
+
+  _ = tryConvertBoxesToStack(in: function, isMandatory: false, context)
+}
+
+/// The "mandatory" version of the pass, which runs in the mandatory pipeline.
+/// In contrast to the regular version, it is a module pass because it deletes the originals
+/// of specialized closures, so that successive diagnostic passes don't report errors for
+/// the unspecialized closures.
+///
+let mandatoryAllocBoxToStack = ModulePass(name: "mandatory-allocbox-to-stack") {
+  (moduleContext: ModulePassContext) in
+
+  var worklist = FunctionWorklist()
+  worklist.pushIfNotVisited(contentsOf: moduleContext.functions)
+
+  var originalsOfSpecializedFunctions = FunctionWorklist()
+
+  while let function = worklist.pop() {
+    moduleContext.transform(function: function) { context in
+      let specFns = tryConvertBoxesToStack(in: function, isMandatory: true, context)
+      worklist.pushIfNotVisited(contentsOf: specFns.specializedFunctions)
+      originalsOfSpecializedFunctions.pushIfNotVisited(contentsOf: specFns.originalFunctions)
+    }
+  }
+
+  /// This is needed because box-promotion is mandatory for non-copyable types. Without removing the
+  /// original, un-specialized versions of closures we risk getting false errors in diagnostic passes.
+  eraseIfDead(functions: originalsOfSpecializedFunctions.functions, moduleContext)
+}
+
+/// Converts all non-escaping `alloc_box` to `alloc_stack` and specializes called functions if a
+/// box is passed to a function.
+/// Returns the list of original functions for which a specialization has been created.
+private func tryConvertBoxesToStack(in function: Function, isMandatory: Bool,
+                                    _ context: FunctionPassContext
+) -> FunctionSpecializations {
+  var promotableBoxes = Array<(AllocBoxInst, Flags)>()
+  var functionsToSpecialize = FunctionSpecializations(isMandatory: isMandatory)
+
+  findPromotableBoxes(in: function, &promotableBoxes, &functionsToSpecialize)
+
+  functionsToSpecialize.createSpecializedFunctions(context)
+
+  for (box, flags) in promotableBoxes {
+    let stack = createAllocStack(for: box, flags: flags, context)
+    functionsToSpecialize.rewriteUses(of: box, with: stack, context)
+    context.erase(instruction: box)
+
+    hoistMarkUnresolvedInsts(stackAddress: stack, checkKind: .consumableAndAssignable, context)
+  }
+  if !promotableBoxes.isEmpty {
+    context.fixStackNesting(in: function)
+  }
+
+  return functionsToSpecialize
+}
+
+private func findPromotableBoxes(in function: Function,
+                                 _ promotableBoxes: inout Array<(AllocBoxInst, Flags)>,
+                                 _ functionsToSpecialize: inout FunctionSpecializations
+) {
+  for inst in function.instructions {
+    if let allocBox = inst as? AllocBoxInst {
+      if let (promotableArgs, flags) = canPromote(allocBox: allocBox) {
+        promotableBoxes.append((allocBox, flags))
+        functionsToSpecialize.add(promotableArguments: promotableArgs)
+      }
+    }
+  }
+}
+
+private typealias Flags = (isLexical: Bool, isFromVarDecl: Bool)
+
+private func canPromote(allocBox: AllocBoxInst) -> (promotableArguments: [FunctionArgument], flags: Flags)? {
+  // For simplicity we only support boxes with a single field. This is okay because SILGen only generates
+  // such kind of boxes.
+  guard allocBox.type.getBoxFields(in: allocBox.parentFunction).count == 1 else {
+    return nil
+  }
+
+  var argumentsToPromote = Array<FunctionArgument>()
+  var flags = (isLexical: false, isFromVarDecl: false)
+
+  // Contains all visited box _and_ closure values (`partial_apply`) of the current function and
+  // all callees, which need to be specialized.
+  var worklist = CrossFunctionValueWorklist()
+  worklist.pushIfNotVisited(allocBox)
+
+  while let value = worklist.pop() {
+    for use in value.uses {
+      // Note: all instructions which are handled here must also be handled in `FunctionSpecializations.rewriteUses`!
+      switch use.instruction {
+      case is StrongRetainInst, is StrongReleaseInst, is ProjectBoxInst, is DestroyValueInst,
+           is EndBorrowInst, is DebugValueInst, is DeallocStackInst:
+        break
+      case let deallocBox as DeallocBoxInst where deallocBox.parentFunction == allocBox.parentFunction:
+        break
+      case let beginBorrow as BeginBorrowInst:
+        flags.isLexical = flags.isLexical || beginBorrow.isLexical
+        flags.isFromVarDecl = flags.isFromVarDecl || beginBorrow.isFromVarDecl
+        fallthrough
+      case is MarkUninitializedInst, is CopyValueInst, is MoveValueInst:
+        worklist.pushIfNotVisited(use.instruction as! SingleValueInstruction)
+      case let apply as ApplySite:
+        if apply.isCallee(operand: use) {
+          // Calling the closure does not escape the closure value.
+          break
+        }
+        guard let callee = apply.getSpecializableCallee() else {
+          return nil
+        }
+        let calleeArg = apply.calleeArgument(of: use, in: callee)!
+        // Continue checking the box (or closure) value in the callee.
+        worklist.pushIfNotVisited(calleeArg)
+
+        if value.type.isBox {
+          // We need to specialize this function by replacing the box argument with an address.
+          argumentsToPromote.append(calleeArg)
+        }
+        if let partialApply = apply as? PartialApplyInst {
+          // We need to check if the captured argument is escaping via the partial_apply.
+          worklist.pushIfNotVisited(partialApply)
+        }
+      default:
+        return nil
+      }
+    }
+  }
+  return (argumentsToPromote, flags)
+}
+
+/// Utility for specializing functions by promoting box arguments to `@inout_aliasable` address arguments.
+private struct FunctionSpecializations {
+
+  // All box arguments (in all functions) which are promoted from box to address.
+  private var promotableArguments = CrossFunctionValueWorklist()
+  private var originals = FunctionWorklist()
+  private var originalToSpecialized = Dictionary<Function, Function>()
+  private let isMandatory: Bool
+
+  init(isMandatory: Bool) { self.isMandatory = isMandatory }
+
+  var originalFunctions: [Function] { originals.functions }
+  var specializedFunctions: [Function] { originals.functions.lazy.map { originalToSpecialized[$0]! } }
+
+  mutating func add(promotableArguments: [FunctionArgument]) {
+    for arg in promotableArguments {
+      self.promotableArguments.pushIfNotVisited(arg)
+      self.originals.pushIfNotVisited(arg.parentFunction)
+    }
+  }
+
+  mutating func createSpecializedFunctions(_ context: FunctionPassContext) {
+    // It's important to first create _all_ declarations before creating the function bodies, because
+    // a function body may reference another specialized declaration - in any order.
+    for f in originals.functions {
+      originalToSpecialized[f] = createSpecializedDeclaration(for: f, context)
+    }
+    for f in originals.functions {
+      createSpecializedBody(for: f, context)
+    }
+  }
+
+  /// Rewrites all uses of `box` with the `stack` address where `box` is either an `alloc_box` in
+  /// the original function or a promoted box argument in a specialized function.
+  func rewriteUses(of box: Value, with stack: Value, _ context: FunctionPassContext) {
+    while let use = box.uses.first {
+      let user = use.instruction
+      switch user {
+      case is StrongRetainInst, is StrongReleaseInst, is DestroyValueInst, is EndBorrowInst, is DeallocBoxInst:
+        context.erase(instruction: user)
+      case let projectBox as ProjectBoxInst:
+        assert(projectBox.fieldIndex == 0, "only single-field boxes are handled")
+        if isMandatory {
+          // Once we have promoted the box to stack, access violations can be detected statically by the
+          // DiagnoseStaticExclusivity pass (which runs after MandatoryAllocBoxToStack).
+          // Therefore we can convert dynamic accesses to static accesses.
+          makeAccessesStatic(of: projectBox, context)
+        }
+        projectBox.replace(with: stack, context)
+      case is MarkUninitializedInst, is CopyValueInst, is BeginBorrowInst, is MoveValueInst:
+        // First, replace the instruction with the original `box`, which adds more uses to `box`.
+        // In a later iteration those additional uses will be handled.
+        (user as! SingleValueInstruction).replace(with: box, context)
+      case let apply as ApplySite:
+        specialize(apply: apply, context)
+      default:
+        fatalError("unhandled box user")
+      }
+    }
+  }
+
+  /// Replaces `apply` with a new apply of the specialized callee.
+  private func specialize(apply: ApplySite, _ context: FunctionPassContext) {
+    let fri = apply.callee as! FunctionRefInst
+    let callee = fri.referencedFunction
+    let builder = Builder(before: apply, context)
+    let newArgs = apply.argumentOperands.map { (argOp) -> Value in
+      if promotableArguments.hasBeenPushed(apply.calleeArgument(of: argOp, in: callee)!) {
+        return builder.createProjectBox(box: argOp.value, fieldIndex: 0)
+      } else {
+        return argOp.value
+      }
+    }
+    let specializedCallee = builder.createFunctionRef(originalToSpecialized[callee]!)
+
+    switch apply {
+    case let applyInst as ApplyInst:
+      let newApply = builder.createApply(function: specializedCallee, applyInst.substitutionMap, arguments: newArgs, isNonThrowing: applyInst.isNonThrowing)
+      applyInst.replace(with: newApply, context)
+    case let partialAp as PartialApplyInst:
+      let newApply = builder.createPartialApply(function: specializedCallee, substitutionMap:
+                                                partialAp.substitutionMap,
+                                                capturedArguments: newArgs,
+                                                calleeConvention: partialAp.calleeConvention,
+                                                hasUnknownResultIsolation: partialAp.hasUnknownResultIsolation,
+                                                isOnStack: partialAp.isOnStack)
+      partialAp.replace(with: newApply, context)
+    case let tryApply as TryApplyInst:
+      builder.createTryApply(function: specializedCallee, tryApply.substitutionMap, arguments: newArgs,
+                             normalBlock: tryApply.normalBlock, errorBlock: tryApply.errorBlock)
+      context.erase(instruction: tryApply)
+    case let beginApply as BeginApplyInst:
+      let newApply = builder.createBeginApply(function: specializedCallee, beginApply.substitutionMap,
+                                              arguments: newArgs)
+      beginApply.replace(with: newApply, context)
+    default:
+      fatalError("unknown apply")
+    }
+    // It is important to delete the dead `function_ref`. Otherwise it will still reference the original
+    // function which prevents deleting it in the mandatory-allocbox-to-stack pass.
+    if fri.uses.isEmpty {
+      context.erase(instruction: fri)
+    }
+  }
+
+  private func createSpecializedDeclaration(for function: Function, _ context: FunctionPassContext) -> Function
+  {
+    let argIndices = function.arguments.enumerated().filter {
+      promotableArguments.hasBeenPushed($0.element)
+    }.map { $0.offset }
+    let name = context.mangle(withBoxToStackPromotedArguments: argIndices, from: function)
+
+    if let existingSpecialization = context.lookupFunction(name: name) {
+      // This can happen if a previous run of the pass already created this specialization.
+      return existingSpecialization
+    }
+
+    let params = function.convention.parameters.enumerated().map { (paramIdx, param) in
+      let arg = function.arguments[function.convention.indirectSILResultCount + paramIdx]
+      if promotableArguments.hasBeenPushed(arg) {
+        return ParameterInfo(type: param.type.getBoxFields(in: function).singleElement!.canonicalType,
+                             convention: .indirectInoutAliasable,
+                             options: 0,
+                             hasLoweredAddresses: param.hasLoweredAddresses)
+      } else {
+        return param
+      }
+    }
+    return context.createSpecializedFunctionDeclaration(from: function, withName: name, withParams: params)
+  }
+
+  private func createSpecializedBody(for original: Function, _ context: FunctionPassContext)
+  {
+    let specializedFunc = originalToSpecialized[original]!
+    if specializedFunc.isDefinition {
+      // This can happen if a previous run of the pass already created this specialization.
+      return
+    }
+    context.buildSpecializedFunction(specializedFunction: specializedFunc) { (specializedFunc, specContext) in
+      cloneFunction(from: original, toEmpty: specializedFunc, specContext)
+
+      replaceBoxWithStackArguments(in: specializedFunc, original: original, specContext)
+    }
+    context.notifyNewFunction(function: specializedFunc, derivedFrom: original)
+  }
+
+  private func replaceBoxWithStackArguments(in specializedFunc: Function, original: Function,
+                                            _ context: FunctionPassContext
+  ) {
+    for (argIdx, (origBoxArg, boxArg)) in zip(original.arguments, specializedFunc.arguments).enumerated() {
+      if promotableArguments.hasBeenPushed(origBoxArg) {
+        let boxFields = boxArg.type.getBoxFields(in: specializedFunc)
+        let stackArg = specializedFunc.entryBlock.insertFunctionArgument(
+          atPosition: argIdx, type: boxFields[0], ownership: .none, decl: boxArg.decl, context)
+        stackArg.copyFlags(from: boxArg, context)
+
+        rewriteUses(of: boxArg, with: stackArg, context)
+        specializedFunc.entryBlock.eraseArgument(at: argIdx + 1, context)
+
+        hoistMarkUnresolvedInsts(
+          stackAddress: stackArg,
+          checkKind: boxFields.isMutable(fieldIndex: 0) ? .consumableAndAssignable : .noConsumeOrAssign,
+          context)
+      }
+    }
+  }
+}
+
+/// Replaces an `alloc_box` with an `alloc_stack` and inserts `destroy_addr` and `dealloc_stack`
+/// at the end of the lifetime.
+private func createAllocStack(for allocBox: AllocBoxInst, flags: Flags, _ context: FunctionPassContext) -> Value {
+  let builder = Builder(before: allocBox, context)
+  let unboxedType = allocBox.type.getBoxFields(in: allocBox.parentFunction)[0]
+  let asi = builder.createAllocStack(unboxedType,
+                                     debugVariable: allocBox.debugVariable,
+                                     hasDynamicLifetime: allocBox.hasDynamicLifetime,
+                                     isLexical: flags.isLexical,
+                                     isFromVarDecl: flags.isFromVarDecl)
+  let stackLocation: Value
+  if let mu = allocBox.uses.getSingleUser(ofType: MarkUninitializedInst.self) {
+    stackLocation = builder.createMarkUninitialized(value: asi, kind: mu.kind)
+  } else {
+    stackLocation = asi
+  }
+
+  for destroy in getFinalDestroys(of: allocBox, context) {
+    let loc = allocBox.location.asCleanup.withScope(of: destroy.location)
+    Builder.insert(after: destroy, location: loc, context) { builder in
+      if !(destroy is DeallocBoxInst),
+         context.deadEndBlocks.isDeadEnd(destroy.parentBlock),
+         !isInLoop(block: destroy.parentBlock, context) {
+        // "Last" releases in dead-end regions may not actually destroy the box
+        // and consequently may not actually release the stored value.  That's
+        // because values (including boxes) may be leaked along paths into
+        // dead-end regions.  Thus it is invalid to lower such final releases of
+        // the box to destroy_addr's/dealloc_box's of the stack-promoted storage.
+        //
+        // There is one exception: if the alloc_box is in a dead-end loop.  In
+        // that case SIL invariants require that the final releases actually
+        // destroy the box; otherwise, a box would leak once per loop.  To check
+        // for this, it is sufficient check that the LastRelease is in a dead-end
+        // loop: if the alloc_box is not in that loop, then the entire loop is in
+        // the live range, so no release within the loop would be a "final
+        // release".
+        //
+        // None of this applies to dealloc_box instructions which always destroy
+        // the box.
+        return
+      }
+      if !unboxedType.isTrivial(in: allocBox.parentFunction), !(destroy is DeallocBoxInst) {
+        builder.createDestroyAddr(address: stackLocation)
+      }
+      if let dbi = destroy as? DeallocBoxInst, dbi.isDeadEnd {
+        // Don't bother to create dealloc_stack instructions in dead-ends.
+        return
+      }
+      builder.createDeallocStack(asi)
+    }
+  }
+  return stackLocation
+}
+
+/// Returns the list of final destroy instructions of `allocBox`.
+/// In case the box is copied, not all `destroy_value`s are final destroys, e.g.
+/// ```
+///   %1 = alloc_box  ${ var T }
+///   %2 = copy_value %1
+///   destroy_value %1            // not a final destroy
+///   destroy_value %2            // a final destroy
+/// ```
+private func getFinalDestroys(of allocBox: AllocBoxInst, _ context: FunctionPassContext) -> [Instruction] {
+  var liverange = InstructionRange(for: allocBox, context)
+  defer { liverange.deinitialize() }
+
+  var worklist = ValueWorklist(context)
+  defer { worklist.deinitialize() }
+  worklist.pushIfNotVisited(allocBox)
+
+  var destroys = Stack<Instruction>(context)
+  defer { destroys.deinitialize() }
+
+  while let value = worklist.pop() {
+    for use in value.uses {
+      let user = use.instruction
+      liverange.insert(user)
+      switch user {
+      case is MarkUninitializedInst, is CopyValueInst, is MoveValueInst, is PartialApplyInst, is BeginBorrowInst:
+        worklist.pushIfNotVisited(user as! SingleValueInstruction)
+      case is StrongReleaseInst, is DestroyValueInst, is DeallocBoxInst:
+        destroys.push(user)
+      case let apply as FullApplySite:
+        if apply.convention(of: use) == .directOwned {
+          destroys.push(user)
+        }
+      default:
+        break
+      }
+    }
+  }
+  return destroys.filter { !liverange.contains($0) }
+}
+
+/// Hoists `mark_unresolved_non_copyable_value` instructions from inside the def-use chain of `stackAddress`
+/// right after the `stackAddress`.
+/// ```
+///    %1 = alloc_stack $T                                %1 = alloc_stack $T
+///    %2 = begin_access [read] %1                  -->   %2 = mark_unresolved_non_copyable_value %1
+///    %3 = mark_unresolved_non_copyable_value %2         %3 = begin_access [read] %2
+/// ```
+private func hoistMarkUnresolvedInsts(stackAddress: Value,
+                                      checkKind: MarkUnresolvedNonCopyableValueInst.CheckKind,
+                                      _ context: FunctionPassContext
+) {
+  var worklist = ValueWorklist(context)
+  defer { worklist.deinitialize() }
+  worklist.pushIfNotVisited(stackAddress)
+  var foundMarkUninit = false
+  while let addr = worklist.pop() {
+    for use in addr.uses {
+      switch use.instruction {
+      case is BeginAccessInst, is MarkUninitializedInst:
+        worklist.pushIfNotVisited(use.instruction as! SingleValueInstruction)
+      case let mu as MarkUnresolvedNonCopyableValueInst:
+        mu.replace(with: mu.operand.value, context)
+        foundMarkUninit = true
+      default:
+        break
+      }
+    }
+  }
+  guard foundMarkUninit else {
+    return
+  }
+  let builder: Builder
+  if let inst = stackAddress as? SingleValueInstruction {
+    builder = Builder(after: inst, context)
+  } else {
+    builder = Builder(atBeginOf: stackAddress.parentBlock, context)
+  }
+  let mu = builder.createMarkUnresolvedNonCopyableValue(value: stackAddress, checkKind: checkKind,  isStrict: false)
+  stackAddress.uses.ignore(user: mu).ignoreDebugUses.ignoreUses(ofType: DeallocStackInst.self)
+    .replaceAll(with: mu, context)
+}
+
+private func makeAccessesStatic(of address: Value, _ context: FunctionPassContext) {
+  for beginAccess in address.uses.users(ofType: BeginAccessInst.self) {
+    if beginAccess.enforcement == .dynamic {
+      beginAccess.set(enforcement: .static, context: context)
+    }
+  }
+}
+
+private extension ApplySite {
+  func getSpecializableCallee() -> Function? {
+    if let callee = referencedFunction,
+       callee.isDefinition,
+       callee.canBeInlinedIntoCaller(withSerializedKind: parentFunction.serializedKind)
+    {
+      if self is FullApplySite,
+         // If the function is inlined later, there is no point in specializing it.
+         !callee.shouldOptimize || callee.inlineStrategy == .heuristicAlways ||
+         callee.inlineStrategy == .always
+      {
+        return nil
+      }
+      return callee
+    }
+    return nil
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CMakeLists.txt b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CMakeLists.txt
index 66aae9c7ad84c..54962dfbcf2cc 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CMakeLists.txt
@@ -7,9 +7,11 @@
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 swift_compiler_sources(Optimizer
+  AllocBoxToStack.swift
   AssumeSingleThreaded.swift
   AsyncDemotion.swift
   BooleanLiteralFolding.swift
+  ConstantCapturePropagation.swift
   CleanupDebugSteps.swift
   ClosureSpecialization.swift
   ComputeEscapeEffects.swift
@@ -24,6 +26,7 @@ swift_compiler_sources(Optimizer
   LifetimeDependenceDiagnostics.swift
   LifetimeDependenceInsertion.swift
   LifetimeDependenceScopeFixup.swift
+  LoopInvariantCodeMotion.swift
   ObjectOutliner.swift
   ObjCBridgingOptimization.swift
   MergeCondFails.swift
@@ -33,4 +36,6 @@ swift_compiler_sources(Optimizer
   SimplificationPasses.swift
   StackPromotion.swift
   StripObjectHeaders.swift
+  TempLValueElimination.swift
+  TempRValueElimination.swift
 )
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ClosureSpecialization.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ClosureSpecialization.swift
index ae4a34a852455..b8dbafcb12afa 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ClosureSpecialization.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ClosureSpecialization.swift
@@ -10,58 +10,106 @@
 //
 //===-----------------------------------------------------------------------===//
 
-/// This file contains the closure-specialization optimizations for general and differentiable Swift.
+import AST
+import SIL
 
-/// General Closure Specialization
-/// ------------------------------------
-/// TODO: Add description when the functionality is added.
+/// Closure Specialization
+/// ----------------------
+/// Specializes functions which take a closure (a `partial_apply` or `thin_to_thick_function` as argument.
+/// The closure is created directly in the specialized function whereas the captured arguments are passed
+/// as additional arguments to the specialized function. As a heuristic, this is only done if the closure
+/// is actually called in the function because after specialization, the closure and its call can be
+/// further optimized, e.g. the closure can be inlined.
+///
+/// ```
+///   %3 = function_ref @closure
+///   %4 = partial_apply %3(%1, %2) : (Float, Int, Bool) -> ()
+///   %5 = function_ref @closure_user
+///   apply %5(%4)
+///   ...
+///
+/// sil @closure_user : ((Float) -> (), Float) -> () {
+/// bb0(%0 : $(Float) -> (), %1 : $Float):
+///   apply %0(%1)
+///   ...
+/// ```
+/// ->
+/// ```
+///   %5 = function_ref @specialized_closure_user
+///   apply %5(%1, %2)
+///   ...
+///
+/// sil @specialized_closure_user : (Float, Int, Bool) -> () {
+/// bb0(%0 : $Float, %1 : $Int, %2 : $Bool):
+///   %3 = function_ref @closure
+///   %4 = partial_apply %3(%1, %2)
+///   apply %3(%0)
+///   ...
+/// ```
+///
+let closureSpecialization = FunctionPass(name: "closure-specialization") {
+  (function: Function, context: FunctionPassContext) in
+
+  guard function.hasOwnership else {
+    return
+  }
+
+  for inst in function.instructions {
+    if let apply = inst as? FullApplySite {
+      _ = trySpecialize(apply: apply, context)
+    }
+  }
+  if context.needFixStackNesting {
+    context.fixStackNesting(in: function)
+  }
+}
 
 /// AutoDiff Closure Specialization
 /// -------------------------------
 /// This optimization performs closure specialization tailored for the patterns seen in Swift Autodiff. In principle,
-/// the optimization does the same thing as the existing closure specialization pass. However, it is tailored to the
+/// the optimization does the same thing as the general closure specialization pass. However, it is tailored to the
 /// patterns of Swift Autodiff.
 ///
 /// The compiler performs reverse-mode differentiation on functions marked with `@differentiable(reverse)`. In doing so,
 /// it generates corresponding VJP and Pullback functions, which perform the forward and reverse pass respectively. You
 /// can think of VJPs as functions that "differentiate" an original function and Pullbacks as the calculated
-/// "derivative" of the original function. 
-/// 
-/// VJPs always return a tuple of 2 values -- the original result and the Pullback. Pullbacks are essentially a chain 
+/// "derivative" of the original function.
+///
+/// VJPs always return a tuple of 2 values -- the original result and the Pullback. Pullbacks are essentially a chain
 /// of closures, where the closure-contexts are implicitly used as the so-called "tape" during the reverse
 /// differentiation process. It is this chain of closures contained within the Pullbacks that this optimization aims
 /// to optimize via closure specialization.
 ///
 /// The code patterns that this optimization targets, look similar to the one below:
 /// ``` swift
-/// 
+///
 /// // Since `foo` is marked with the `differentiable(reverse)` attribute the compiler
 /// // will generate corresponding VJP and Pullback functions in SIL. Let's assume that
 /// // these functions are called `vjp_foo` and `pb_foo` respectively.
-/// @differentiable(reverse) 
-/// func foo(_ x: Float) -> Float { 
+/// @differentiable(reverse)
+/// func foo(_ x: Float) -> Float {
 ///   return sin(x)
 /// }
 ///
-/// //============== Before closure specialization ==============// 
+/// //============== Before closure specialization ==============//
 /// // VJP of `foo`. Returns the original result and the Pullback of `foo`.
-/// sil @vjp_foo: $(Float) -> (originalResult: Float, pullback: (Float) -> Float) { 
-/// bb0(%0: $Float): 
-///   // __Inlined__ `vjp_sin`: It is important for all intermediate VJPs to have 
+/// sil @vjp_foo: $(Float) -> (originalResult: Float, pullback: (Float) -> Float) {
+/// bb0(%0: $Float):
+///   // __Inlined__ `vjp_sin`: It is important for all intermediate VJPs to have
 ///   // been inlined in `vjp_foo`, otherwise `vjp_foo` will not be able to determine
 ///   // that `pb_foo` is closing over other closures and no specialization will happen.
-///                                                                               \        
+///                                                                               \
 ///   %originalResult = apply @sin(%0): $(Float) -> Float                          \__ Inlined `vjp_sin`
 ///   %partially_applied_pb_sin = partial_apply pb_sin(%0): $(Float) -> Float      /
-///                                                                               /  
+///                                                                               /
 ///
 ///   %pb_foo = function_ref @pb_foo: $@convention(thin) (Float, (Float) -> Float) -> Float
 ///   %partially_applied_pb_foo = partial_apply %pb_foo(%partially_applied_pb_sin): $(Float, (Float) -> Float) -> Float
-///  
+///
 ///   return (%originalResult, %partially_applied_pb_foo)
 /// }
 ///
-/// // Pullback of `foo`. 
+/// // Pullback of `foo`.
 /// //
 /// // It receives what are called as intermediate closures that represent
 /// // the calculations that the Pullback needs to perform to calculate a function's
@@ -70,1040 +118,629 @@
 /// // The intermediate closures may themselves contain intermediate closures and
 /// // that is why the Pullback for a function differentiated at the "top" level
 /// // may end up being a "chain" of closures.
-/// sil @pb_foo: $(Float, (Float) -> Float) -> Float { 
-/// bb0(%0: $Float, %pb_sin: $(Float) -> Float): 
-///   %derivative_of_sin = apply %pb_sin(%0): $(Float) -> Float 
+/// sil @pb_foo: $(Float, (Float) -> Float) -> Float {
+/// bb0(%0: $Float, %pb_sin: $(Float) -> Float):
+///   %derivative_of_sin = apply %pb_sin(%0): $(Float) -> Float
 ///   return %derivative_of_sin: Float
 /// }
 ///
-/// //============== After closure specialization ==============// 
-/// sil @vjp_foo: $(Float) -> (originalResult: Float, pullback: (Float) -> Float) { 
-/// bb0(%0: $Float): 
-///   %originalResult = apply @sin(%0): $(Float) -> Float 
-/// 
+/// //============== After closure specialization ==============//
+/// sil @vjp_foo: $(Float) -> (originalResult: Float, pullback: (Float) -> Float) {
+/// bb0(%0: $Float):
+///   %originalResult = apply @sin(%0): $(Float) -> Float
+///
 ///   // Before the optimization, pullback of `foo` used to take a closure for computing
 ///   // pullback of `sin`. Now, the specialized pullback of `foo` takes the arguments that
 ///   // pullback of `sin` used to close over and pullback of `sin` is instead copied over
 ///   // inside pullback of `foo`.
 ///   %specialized_pb_foo = function_ref @specialized_pb_foo: $@convention(thin) (Float, Float) -> Float
-///   %partially_applied_pb_foo = partial_apply %specialized_pb_foo(%0): $(Float, Float) -> Float 
-/// 
+///   %partially_applied_pb_foo = partial_apply %specialized_pb_foo(%0): $(Float, Float) -> Float
+///
 ///   return (%originalResult, %partially_applied_pb_foo)
 /// }
-/// 
-/// sil @specialized_pb_foo: $(Float, Float) -> Float { 
-/// bb0(%0: $Float, %1: $Float): 
-///   %2 = partial_apply @pb_sin(%1): $(Float) -> Float 
-///   %3 = apply %2(): $() -> Float 
+///
+/// sil @specialized_pb_foo: $(Float, Float) -> Float {
+/// bb0(%0: $Float, %1: $Float):
+///   %2 = partial_apply @pb_sin(%1): $(Float) -> Float
+///   %3 = apply %2(): $() -> Float
 ///   return %3: $Float
 /// }
 /// ```
-
-import AST
-import SIL
-import SILBridging
-
-private let verbose = false
-
-private func log(_ message: @autoclosure () -> String) {
-  if verbose {
-    print("### \(message())")
-  }
-}
-
-// =========== Entry point =========== //
-let generalClosureSpecialization = FunctionPass(name: "experimental-swift-based-closure-specialization") {
-  (function: Function, context: FunctionPassContext) in
-  // TODO: Implement general closure specialization optimization
-  print("NOT IMPLEMENTED")
-}
-
+///
 let autodiffClosureSpecialization = FunctionPass(name: "autodiff-closure-specialization") {
   (function: Function, context: FunctionPassContext) in
 
+  guard function.hasOwnership else {
+    return
+  }
+
   guard !function.isDefinedExternally,
-        function.isAutodiffVJP,
-        function.blocks.singleElement != nil else {
+    function.isAutodiffVJP
+  else {
     return
   }
-  
+
   var remainingSpecializationRounds = 5
-  var callerModified = false
 
   repeat {
-    var callSites = gatherCallSites(in: function, context)
-
-    if !callSites.isEmpty {
-      for callSite in callSites {
-        var (specializedFunction, alreadyExists) = getOrCreateSpecializedFunction(basedOn: callSite, context)
-
-        if !alreadyExists {
-          context.notifyNewFunction(function: specializedFunction, derivedFrom: callSite.applyCallee)
-        }
-
-        rewriteApplyInstruction(using: specializedFunction, callSite: callSite, context)
-      }
-
-      var deadClosures: InstructionWorklist = callSites.reduce(into: InstructionWorklist(context)) { deadClosures, callSite in
-        callSite.closureArgDescriptors
-          .map { $0.closure }
-          .forEach { deadClosures.pushIfNotVisited($0) }
-      }
-
-      defer {
-        deadClosures.deinitialize()
-      }
-
-      while let deadClosure = deadClosures.pop() {
-        let isDeleted = context.tryDeleteDeadClosure(closure: deadClosure as! SingleValueInstruction)
-        if isDeleted {
-          context.notifyInvalidatedStackNesting()
+    var changed = false
+    for inst in function.instructions {
+      if let partialApply = inst as? PartialApplyInst,
+         partialApply.isPullbackInResultOfAutodiffVJP
+      {
+        if trySpecialize(apply: partialApply, context) {
+          changed = true
         }
       }
-
-      if context.needFixStackNesting {
-        function.fixStackNesting(context)
-      }
+    }
+    if context.needFixStackNesting {
+      context.fixStackNesting(in: function)
+    }
+    if !changed {
+      break
     }
 
-    callerModified = callSites.count > 0
     remainingSpecializationRounds -= 1
-  } while callerModified && remainingSpecializationRounds > 0
+  } while remainingSpecializationRounds > 0
 }
 
-// =========== Top-level functions ========== //
-
-private let specializationLevelLimit = 2
-
-private func gatherCallSites(in caller: Function, _ context: FunctionPassContext) -> [CallSite] {
-  /// __Root__ closures created via `partial_apply` or `thin_to_thick_function` may be converted and reabstracted
-  /// before finally being used at an apply site. We do not want to handle these intermediate closures separately
-  /// as they are handled and cloned into the specialized function as part of the root closures. Therefore, we keep 
-  /// track of these intermediate closures in a set. 
-  /// 
-  /// This set is populated via the `markConvertedAndReabstractedClosuresAsUsed` function which is called when we're
-  /// handling the different uses of our root closures.
-  ///
-  /// Below SIL example illustrates the above point.
-  /// ```                                                                                                      
-  /// // The below set of a "root" closure and its reabstractions/conversions
-  /// // will be handled as a unit and the entire set will be copied over
-  /// // in the specialized version of `takesClosure` if we determine that we  
-  /// // can specialize `takesClosure` against its closure argument.
-  ///                                                                                                          __            
-  /// %someFunction = function_ref @someFunction: $@convention(thin) (Int, Int) -> Int                            \ 
-  /// %rootClosure = partial_apply [callee_guaranteed] %someFunction (%someInt): $(Int, Int) -> Int                \
-  /// %thunk = function_ref @reabstractionThunk : $@convention(thin) (@callee_guaranteed (Int) -> Int) -> @out Int /     
-  /// %reabstractedClosure = partial_apply [callee_guaranteed] %thunk(%rootClosure) :                             /      
-  ///                        $@convention(thin) (@callee_guaranteed (Int) -> Int) -> @out Int                  __/       
-  /// 
-  /// %takesClosure = function_ref @takesClosure : $@convention(thin) (@owned @callee_guaranteed (Int) -> @out Int) -> Int
-  /// %result = partial_apply %takesClosure(%reabstractedClosure) : $@convention(thin) (@owned @callee_guaranteed () -> @out Int) -> Int
-  /// ret %result
-  /// ```
-  var convertedAndReabstractedClosures = InstructionSet(context)
-
-  defer {
-    convertedAndReabstractedClosures.deinitialize()
-  }
-
-  var callSiteMap = CallSiteMap()
+// ===================== Utility functions and extensions ===================== //
 
-  for inst in caller.instructions {
-    if !convertedAndReabstractedClosures.contains(inst),
-       let rootClosure = inst.asSupportedClosure
-    {
-      updateCallSites(for: rootClosure, in: &callSiteMap, 
-                      convertedAndReabstractedClosures: &convertedAndReabstractedClosures, context)
-    }
+private func trySpecialize(apply: ApplySite, _ context: FunctionPassContext) -> Bool {
+  guard isCalleeSpecializable(of: apply),
+        let specialization = analyzeArguments(of: apply, context)
+  else {
+    return false
   }
 
-  return callSiteMap.callSites
-}
+  // We need to make each captured argument of all closures a unique Value. Otherwise the Cloner would
+  // wrongly map added capture arguments to the re-generated closure in the specialized function:
+  //
+  //   %4 = partial_apply %3(%1, %1) : (Int, Int) -> ()  // %1 is captured twice
+  //
+  // sil @specialized_closure_user : (Int, Int) -> () {
+  // bb0(%0 : $Int, %1 : $Int):
+  //   %3 = function_ref @closure
+  //   %4 = partial_apply %3(%0, %0)   <- instead of an argument list of `(%0, %1)`!
+  //
+  // This wouldn't be a problem per se - the code is correct. However, this is not reflected in the mangling.
+  // And the same specialized function could be re-used at a call-site where not two identical values are
+  // passed to the closure.
+  //
+  specialization.uniqueCaptureArguments(context)
 
-private func getOrCreateSpecializedFunction(basedOn callSite: CallSite, _ context: FunctionPassContext)
-  -> (function: Function, alreadyExists: Bool)
-{
-  let specializedFunctionName = callSite.specializedCalleeName(context)
-  if let specializedFunction = context.lookupFunction(name: specializedFunctionName) {
-    return (specializedFunction, true)
-  }
+  let specializedFunction = specialization.getOrCreateSpecializedFunction(context)
 
-  let applySiteCallee = callSite.applyCallee
-  let specializedParameters = applySiteCallee.convention.getSpecializedParameters(basedOn: callSite)
+  specialization.unUniqueCaptureArguments(context)
 
-  let specializedFunction = 
-    context.createFunctionForClosureSpecialization(from: applySiteCallee, withName: specializedFunctionName, 
-                                                   withParams: specializedParameters, 
-                                                   withSerialization: applySiteCallee.isSerialized)
+  specialization.rewriteApply(for: specializedFunction, context)
 
-  context.buildSpecializedFunction(specializedFunction: specializedFunction,
-                                   buildFn: { (emptySpecializedFunction, functionPassContext) in 
-                                      let closureSpecCloner = SpecializationCloner(emptySpecializedFunction: emptySpecializedFunction, functionPassContext)
-                                      closureSpecCloner.cloneAndSpecializeFunctionBody(using: callSite)
-                                   })
+  specialization.deleteDeadClosures(context)
 
-  return (specializedFunction, false)
+  return true
 }
 
-private func rewriteApplyInstruction(using specializedCallee: Function, callSite: CallSite, 
-                                     _ context: FunctionPassContext) {
-  let newApplyArgs = callSite.getArgumentsForSpecializedApply(of: specializedCallee)
+private func isCalleeSpecializable(of apply: ApplySite) -> Bool {
+  if let callee = apply.referencedFunction,
+     callee.isDefinition,
 
-  for newApplyArg in newApplyArgs {
-    if case let .PreviouslyCaptured(capturedArg, needsRetain, parentClosureArgIndex) = newApplyArg,
-       needsRetain 
-    {
-      let closureArgDesc = callSite.closureArgDesc(at: parentClosureArgIndex)!
-      var builder = Builder(before: closureArgDesc.closure, context)
-
-      // TODO: Support only OSSA instructions once the OSSA elimination pass is moved after all function optimization 
-      // passes.
-      if callSite.applySite.parentBlock != closureArgDesc.closure.parentBlock {
-        // Emit the retain and release that keeps the argument live across the callee using the closure.
-        builder.createRetainValue(operand: capturedArg)
-
-        for instr in closureArgDesc.lifetimeFrontier {
-          builder = Builder(before: instr, context)
-          builder.createReleaseValue(operand: capturedArg)
-        }
+     // We don't support generic functions (yet)
+     !apply.hasSubstitutions,
 
-        // Emit the retain that matches the captured argument by the partial_apply in the callee that is consumed by
-        // the partial_apply.
-        builder = Builder(before: callSite.applySite, context)
-        builder.createRetainValue(operand: capturedArg)
-      } else {
-        builder.createRetainValue(operand: capturedArg)
-      }
-    }
-  }
+     // Don't specialize non-fragile (read as non-serialized) callees if the caller is fragile; the
+     // specialized callee will have shared linkage, and thus cannot be referenced from the fragile caller.
+     !(apply.parentFunction.isSerialized && !callee.isSerialized),
 
-  // Rewrite apply instruction
-  var builder = Builder(before: callSite.applySite, context)
-  let oldApply = callSite.applySite as! PartialApplyInst
-  let funcRef = builder.createFunctionRef(specializedCallee)
-  let capturedArgs = Array(newApplyArgs.map { $0.value })
-
-  let newApply = builder.createPartialApply(function: funcRef, substitutionMap: SubstitutionMap(), 
-                                            capturedArguments: capturedArgs, calleeConvention: oldApply.calleeConvention,
-                                            hasUnknownResultIsolation: oldApply.hasUnknownResultIsolation,
-                                            isOnStack: oldApply.isOnStack)
-
-  builder = Builder(before: callSite.applySite.next!, context)
-  // TODO: Support only OSSA instructions once the OSSA elimination pass is moved after all function optimization 
-  // passes.
-  for closureArgDesc in callSite.closureArgDescriptors {
-    if closureArgDesc.isClosureConsumed,
-       !closureArgDesc.isPartialApplyOnStack,
-       !closureArgDesc.parameterInfo.isTrivialNoescapeClosure
-    {
-      builder.createReleaseValue(operand: closureArgDesc.closure)
-    }
+     // If the callee uses a dynamic Self, we cannot specialize it, since the resulting specialization
+     // might no longer have 'self' as the last parameter.
+     //
+     // TODO: Keep the self argument the last when appending arguments.
+     !callee.mayBindDynamicSelf
+  {
+    return true
   }
-
-  oldApply.replace(with: newApply, context)
+  return false
 }
 
-// ===================== Utility functions and extensions ===================== //
-
-private func updateCallSites(for rootClosure: SingleValueInstruction, in callSiteMap: inout CallSiteMap, 
-                             convertedAndReabstractedClosures: inout InstructionSet, _ context: FunctionPassContext) {
-  var rootClosurePossibleLiveRange = InstructionRange(begin: rootClosure, context)
-  defer {
-    rootClosurePossibleLiveRange.deinitialize()
-  }
+private func analyzeArguments(of apply: ApplySite, _ context: FunctionPassContext) -> SpecializationInfo? {
+  var argumentsToSpecialize = [(Operand, Closure)]()
+  var rootClosures = [PartialApplyInst]()
+  var rootClosuresAdded = InstructionSet(context)
+  defer { rootClosuresAdded.deinitialize() }
 
-  var rootClosureApplies = OperandWorklist(context)                            
-  defer {
-    rootClosureApplies.deinitialize()
+  for argOp in apply.argumentOperands {
+    var visited = ValueSet(context)
+    defer { visited.deinitialize() }
+    if let closure = findSpecializableClosure(of: argOp.value, &visited),
+       // Ok, we know that we can perform the optimization but not whether or not the optimization
+       // is profitable. Check if the closure is actually called in the callee (or in a function
+       // called by the callee). This opens optimization opportunities, like inlining.
+       isClosureApplied(apply.calleeArgument(of: argOp, in: apply.referencedFunction!)!)
+    {
+      argumentsToSpecialize.append((argOp, closure))
+      if let partialApply = closure as? PartialApplyInst,
+         rootClosuresAdded.insert(partialApply)
+      {
+        rootClosures.append(partialApply)
+      }
+    }
   }
-
-  // A "root" closure undergoing conversions and/or reabstractions has additional restrictions placed upon it, in order
-  // for a call site to be specialized against it. We handle conversion/reabstraction uses before we handle apply uses
-  // to gather the parameters required to evaluate these restrictions or to skip call site uses of "unsupported" 
-  // closures altogether.
-  //
-  // There are currently 2 restrictions that are evaluated prior to specializing a callsite against a converted and/or 
-  // reabstracted closure -
-  // 1. A reabstracted root closure can only be specialized against, if the reabstracted closure is ultimately passed
-  //    trivially (as a noescape+thick function) into the call site.
-  //
-  // 2. A root closure may be a partial_apply [stack], in which case we need to make sure that all mark_dependence 
-  //    bases for it will be available in the specialized callee in case the call site is specialized against this root
-  //    closure.
-
-  let (foundUnexpectedUse, haveUsedReabstraction) = 
-    handleNonApplies(for: rootClosure, rootClosureApplies: &rootClosureApplies,
-                     rootClosurePossibleLiveRange: &rootClosurePossibleLiveRange, context);
-
-
-  if foundUnexpectedUse {
-    return
+  if argumentsToSpecialize.isEmpty {
+    return nil
   }
-
-  let intermediateClosureArgDescriptorData = 
-    handleApplies(for: rootClosure, callSiteMap: &callSiteMap, rootClosureApplies: &rootClosureApplies, 
-                  rootClosurePossibleLiveRange: &rootClosurePossibleLiveRange, 
-                  convertedAndReabstractedClosures: &convertedAndReabstractedClosures,
-                  haveUsedReabstraction: haveUsedReabstraction, context)
-
-  finalizeCallSites(for: rootClosure, in: &callSiteMap, 
-                    rootClosurePossibleLiveRange: rootClosurePossibleLiveRange,
-                    intermediateClosureArgDescriptorData: intermediateClosureArgDescriptorData, context)
+  return SpecializationInfo(apply: apply, closureArguments: argumentsToSpecialize, rootClosures: rootClosures)
 }
 
-/// Handles all non-apply direct and transitive uses of `rootClosure`.
-///
-/// Returns: 
-/// haveUsedReabstraction - whether the root closure is reabstracted via a thunk 
-/// foundUnexpectedUse - whether the root closure is directly or transitively used in an instruction that we don't know
-///                      how to handle. If true, then `rootClosure` should not be specialized against.
-private func handleNonApplies(for rootClosure: SingleValueInstruction, 
-                              rootClosureApplies: inout OperandWorklist,
-                              rootClosurePossibleLiveRange: inout InstructionRange, 
-                              _ context: FunctionPassContext) 
-  -> (foundUnexpectedUse: Bool, haveUsedReabstraction: Bool)
-{
-  var foundUnexpectedUse = false
-  var haveUsedReabstraction = false
-
-  /// The root closure or an intermediate closure created by reabstracting the root closure may be a `partial_apply
-  /// [stack]` and we need to make sure that all `mark_dependence` bases for this `onStack` closure will be available in
-  /// the specialized callee, in case the call site is specialized against this root closure.
-  ///
-  /// `possibleMarkDependenceBases` keeps track of all potential values that may be used as bases for creating
-  /// `mark_dependence`s for our `onStack` root/reabstracted closures. For root closures these values are non-trivial
-  /// closure captures (which are always available as function arguments in the specialized callee). For reabstracted
-  /// closures these values may be the root closure or its conversions (below is a short SIL example representing this
-  /// case).
-  /// ```
-  /// %someFunction = function_ref @someFunction : $@convention(thin) (Int) -> Int
-  /// %rootClosure = partial_apply [callee_guaranteed] %someFunction(%someInt) : $@convention(thin) (Int) -> Int
-  /// %noescapeRootClosure = convert_escape_to_noescape %rootClosure : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
-  /// %thunk = function_ref @reabstractionThunk : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-  /// %thunkedRootClosure = partial_apply [callee_guaranteed] [on_stack] %thunk(%noescapeRootClosure) : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-  /// %dependency = mark_dependence %thunkedRootClosure : $@noescape @callee_guaranteed () -> @out Int on %noescapeClosure : $@noescape @callee_guaranteed () -> Int
-  /// %takesClosure = function_ref @takesClosure : $@convention(thin) (@owned @noescape @callee_guaranteed () -> @out Int)
-  /// %ret = apply %takesClosure(%dependency) : $@convention(thin) (@owned @noescape @callee_guaranteed () -> @out Int)
-  /// ```
-  ///
-  /// Any value outside of the aforementioned values is not going to be available in the specialized callee and a
-  /// `mark_dependence` of the root closure on such a value means that we cannot specialize the call site against it.
-  var possibleMarkDependenceBases = ValueSet(context)
-  defer {
-    possibleMarkDependenceBases.deinitialize()
-  }
+// Walks down the use-def chain of a function argument, recursively, to find a rootClosure.
+private func findSpecializableClosure(of value: Value, _ visited: inout ValueSet) -> Closure? {
+  visited.insert(value)
 
-  var rootClosureConversionsAndReabstractions = OperandWorklist(context)                            
-  rootClosureConversionsAndReabstractions.pushIfNotVisited(contentsOf: rootClosure.uses)
-  defer {
-    rootClosureConversionsAndReabstractions.deinitialize()
-  }
+  let specializationLevelLimit = 2
 
-  if let pai = rootClosure as? PartialApplyInst {
-    for arg in pai.arguments {
-      possibleMarkDependenceBases.insert(arg)
-    }
-  }
-  
-  while let use = rootClosureConversionsAndReabstractions.pop() {
-    switch use.instruction {
-    case let cfi as ConvertFunctionInst:
-      rootClosureConversionsAndReabstractions.pushIfNotVisited(contentsOf: cfi.uses)
-      possibleMarkDependenceBases.insert(cfi)
-      rootClosurePossibleLiveRange.insert(use.instruction)
-
-    case let cvt as ConvertEscapeToNoEscapeInst:
-      rootClosureConversionsAndReabstractions.pushIfNotVisited(contentsOf: cvt.uses)
-      possibleMarkDependenceBases.insert(cvt)
-      rootClosurePossibleLiveRange.insert(use.instruction)
-
-    case let pai as PartialApplyInst:
-      if !pai.isPullbackInResultOfAutodiffVJP,
-          pai.isSupportedClosure,
-          pai.isPartialApplyOfThunk,
-          // Argument must be a closure
-          pai.arguments[0].type.isThickFunction 
-      {
-        rootClosureConversionsAndReabstractions.pushIfNotVisited(contentsOf: pai.uses)
-        possibleMarkDependenceBases.insert(pai)
-        rootClosurePossibleLiveRange.insert(use.instruction)
-        haveUsedReabstraction = true
-      } else if pai.isPullbackInResultOfAutodiffVJP {
-        rootClosureApplies.pushIfNotVisited(use)
-      }
-
-    case let mv as MoveValueInst:
-      rootClosureConversionsAndReabstractions.pushIfNotVisited(contentsOf: mv.uses)
-      possibleMarkDependenceBases.insert(mv)
-      rootClosurePossibleLiveRange.insert(use.instruction)
+  switch value {
+  case is ConvertFunctionInst,
+       is ConvertEscapeToNoEscapeInst,
+       is MoveValueInst,
+       is CopyValueInst:
+    return findSpecializableClosure(of: (value as! UnaryInstruction).operand.value, &visited)
 
-    case let mdi as MarkDependenceInst:
-      if possibleMarkDependenceBases.contains(mdi.base),  
-          mdi.value == use.value,
-          mdi.value.type.isNoEscapeFunction,
-          mdi.value.type.isThickFunction
-      {
-        rootClosureConversionsAndReabstractions.pushIfNotVisited(contentsOf: mdi.uses)
-        rootClosurePossibleLiveRange.insert(use.instruction)
-      }
-    
-    case is CopyValueInst,
-         is DestroyValueInst,
-         is RetainValueInst,
-         is ReleaseValueInst,
-         is StrongRetainInst,
-         is StrongReleaseInst:
-      rootClosurePossibleLiveRange.insert(use.instruction)
-
-    case let ti as TupleInst:
-      if ti.parentFunction.isAutodiffVJP,
-         let returnInst = ti.parentFunction.returnInstruction,
-         ti == returnInst.returnedValue
-      {
-        // This is the pullback closure returned from an Autodiff VJP and we don't need to handle it.
-      } else {
-        fallthrough
-      }
+  case let mdi as MarkDependenceInst:
+    guard mdi.value.type.isNoEscapeFunction, mdi.value.type.isThickFunction else {
+      return nil
+    }
+    guard let operandClosure = findSpecializableClosure(of: mdi.value, &visited) else {
+      return nil
+    }
+    // Make sure that the mark_dependence's base is part of the use-def chain and will therefore be cloned as well.
+    if !visited.contains(mdi.base) {
+      return nil
+    }
+    return operandClosure
+
+  case let partialApply as PartialApplyInst:
+    // Don't specialize for re-abstractions via a partial_apply, but treat such re-abstractions like
+    // closure "conversions". E.g.
+    // ```
+    //   %1 = partial_apply             // root closure
+    //   %2 = function_ref @thunk
+    //   %3 = partial_apply %2(%1)      // re-abstraction
+    //   apply %f(%3)
+    // ```
+    if partialApply.isPartialApplyOfThunk,
+       let argumentClosure = findSpecializableClosure(of: partialApply.arguments[0], &visited)
+    {
+      return argumentClosure
+    }
+    guard let callee = partialApply.referencedFunction,
+          !partialApply.hasSubstitutions,
+
+          // Avoid an infinite specialization loop caused by repeated runs of ClosureSpecialization and
+          // ConstantCapturePropagation.
+          // ConstantCapturePropagation propagates constant function-literals. Such function specializations
+          // can then be optimized again by ClosureSpecialization and so on. This happens if a closure argument
+          // is called _and_ referenced in another closure, which is passed to a recursive call. E.g.
+          //
+          // func foo(_ c: @escaping () -> ()) {
+          //  c() foo({ c() })
+          // }
+          //
+          // A limit of 2 is good enough and will not be exceed in "regular" optimization scenarios.
+          callee.specializationLevel <= specializationLevelLimit,
+
+          // Functions with a readnone, readonly or releasenone effect and a consumed captures cannot be
+          // specialized because the captured arguments are passed as owned arguments to the specialized
+          // function. Destroy for such arguments in the specialized function violates the effect.
+          (partialApply.isOnStack || callee.effectAllowsSpecialization),
+
+          // TODO: handle other kind of indirect arguments
+          partialApply.hasOnlyInoutIndirectArguments,
+
+          (partialApply.isOnStack || partialApply.allArgumentsCanBeCopied)
+    else {
+      return nil
+    }
+    return partialApply
 
-    default:
-      foundUnexpectedUse = true
-      log("Found unexpected direct or transitive user of root closure: \(use.instruction)")
-      return (foundUnexpectedUse, haveUsedReabstraction)      
+  case let tttfi as ThinToThickFunctionInst:
+    guard let callee = tttfi.referencedFunction,
+          callee.specializationLevel <= specializationLevelLimit
+    else {
+      return nil
     }
-  }
+    return tttfi
 
-  return (foundUnexpectedUse, haveUsedReabstraction)
+  default:
+    return nil
+  }
 }
 
-private typealias IntermediateClosureArgDescriptorDatum = (applySite: SingleValueInstruction, closureArgIndex: Int, paramInfo: ParameterInfo)
-
-private func handleApplies(for rootClosure: SingleValueInstruction, callSiteMap: inout CallSiteMap, 
-                           rootClosureApplies: inout OperandWorklist, 
-                           rootClosurePossibleLiveRange: inout InstructionRange, 
-                           convertedAndReabstractedClosures: inout InstructionSet, haveUsedReabstraction: Bool, 
-                           _ context: FunctionPassContext) -> [IntermediateClosureArgDescriptorDatum] 
-{
-  var intermediateClosureArgDescriptorData: [IntermediateClosureArgDescriptorDatum] = []
-  
-  while let use = rootClosureApplies.pop() {
-    rootClosurePossibleLiveRange.insert(use.instruction)
-
-    // TODO [extend to general swift]: Handle full apply sites
-    guard let pai = use.instruction as? PartialApplyInst else {
-      continue
-    }
+/// Either a `partial_apply` or a `thin_to_thick_function`
+private typealias Closure = SingleValueInstruction
 
-    // TODO: Handling generic closures may be possible but is not yet implemented
-    if pai.hasSubstitutions || !pai.calleeIsDynamicFunctionRef || !pai.isPullbackInResultOfAutodiffVJP {
-      continue
-    }
+/// Information about the function to be specialized and for which closure arguments.
+private struct SpecializationInfo {
 
-    guard let callee = pai.referencedFunction else {
-      continue
-    }
+  // The apply which we want to specialize
+  let apply: ApplySite
 
-    // Workaround for a problem with OSSA: https://github.com/swiftlang/swift/issues/78847
-    // TODO: remove this if-statement once the underlying problem is fixed.
-    if callee.hasOwnership {
-      continue
-    }
+  // All closure arguments of the apply which we want to replace (usually there is one, but there can be
+  // multiple).
+  // Note that the `Closure` is not necessarily the value of the `Operand`. There can be function conventions
+  // and re-abstractions (via a thunk) in-between:
+  //
+  //   %4 = partial_apply %3(%1) : (Int) -> ()   // %4 = rootClosure
+  //   %5 = convert_function %4
+  //   %6 = copy_value %5
+  //   apply %5(%5)                              // %5 = closureArgument
+  //
+  let closureArguments: [(closureArgument: Operand, rootClosure: Closure)]
 
-    if callee.isDefinedExternally {
-      continue
-    }
+  // All rootClosures of `closureArguments` which are `partial_apply`s, and uniqued: if a rootClosure
+  // appears multiple times in `closureArguments`, it's only added a single time here.
+  let rootClosures: [PartialApplyInst]
 
-    // Don't specialize non-fragile (read as non-serialized) callees if the caller is fragile; the specialized callee
-    // will have shared linkage, and thus cannot be referenced from the fragile caller.
-    let caller = rootClosure.parentFunction
-    if caller.isSerialized && !callee.isSerialized {
-      continue
-    }
+  // The function to specialize
+  var callee: Function { apply.referencedFunction! }
 
-    // If the callee uses a dynamic Self, we cannot specialize it, since the resulting specialization might no longer
-    // have 'self' as the last parameter.
-    //
-    // TODO: We could fix this by inserting new arguments more carefully, or changing how we model dynamic Self
-    // altogether.
-    if callee.mayBindDynamicSelf {
-      continue
-    }
+  private typealias Cloner = SIL.Cloner<FunctionPassContext>
 
-    // Proceed if the closure is passed as an argument (and not called). If it is called we have nothing to do.
-    //
-    // `closureArgumentIndex` is the index of the closure in the callee's argument list.
-    guard let closureArgumentIndex = pai.calleeArgumentIndex(of: use) else {
-      continue
-    }
+  func getOrCreateSpecializedFunction(_ context: FunctionPassContext) -> Function {
+    let specializedFunctionName = getSpecializedFunctionName(context)
 
-    // Ok, we know that we can perform the optimization but not whether or not the optimization is profitable. Check if
-    // the closure is actually called in the callee (or in a function called by the callee).
-    if !isClosureApplied(in: callee, closureArgIndex: closureArgumentIndex) {
-      continue
+    if let existingSpecializedFunction = context.lookupFunction(name: specializedFunctionName) {
+      return existingSpecializedFunction
     }
 
-    let onlyHaveThinToThickClosure = rootClosure is ThinToThickFunctionInst && !haveUsedReabstraction
+    let specializedParameters = getSpecializedParameters()
 
-    guard let closureParamInfo = pai.operandConventions[parameter: use.index] else {
-      fatalError("While handling apply uses, parameter info not found for operand: \(use)!")
-    }
+    let specializedFunction =
+      context.createSpecializedFunctionDeclaration(
+        from: callee, withName: specializedFunctionName,
+        withParams: specializedParameters,
+        // The specialized function is always a thin function. This is important because we add additional
+        // parameters after the Self parameter of witness methods. In this case the new function is not a
+        // method anymore.
+        makeThin: true, makeBare: true)
 
-    // If we are going to need to release the copied over closure, we must make sure that we understand all the exit
-    // blocks, i.e., they terminate with an instruction that clearly indicates whether to release the copied over 
-    // closure or leak it.
-    if closureParamInfo.convention.isGuaranteed,
-       !onlyHaveThinToThickClosure,
-       !callee.blocks.allSatisfy({ $0.isReachableExitBlock || $0.terminator is UnreachableInst })
-    {
-      continue
-    }
+    context.buildSpecializedFunction(
+      specializedFunction: specializedFunction,
+      buildFn: { (specializedFunction, specializedContext) in
+        var cloner = Cloner(cloneToEmptyFunction: specializedFunction, specializedContext)
+        defer { cloner.deinitialize() }
 
-    // Functions with a readnone, readonly or releasenone effect and a nontrivial context cannot be specialized.
-    // Inserting a release in such a function results in miscompilation after other optimizations. For now, the
-    // specialization is disabled.
-    //
-    // TODO: A @noescape closure should never be converted to an @owned argument regardless of the function's effect
-    // attribute.
-    if !callee.effectAllowsSpecialization && !onlyHaveThinToThickClosure {
-      continue
-    }
+        cloneAndSpecializeFunctionBody(using: &cloner)
+      })
 
-    // Avoid an infinite specialization loop caused by repeated runs of ClosureSpecializer and CapturePropagation.
-    // CapturePropagation propagates constant function-literals. Such function specializations can then be optimized
-    // again by the ClosureSpecializer and so on. This happens if a closure argument is called _and_ referenced in
-    // another closure, which is passed to a recursive call. E.g.
-    //
-    // func foo(_ c: @escaping () -> ()) { 
-    //  c() foo({ c() })
-    // }
-    //
-    // A limit of 2 is good enough and will not be exceed in "regular" optimization scenarios.
-    let closureCallee = rootClosure is PartialApplyInst 
-                        ? (rootClosure as! PartialApplyInst).referencedFunction!
-                        : (rootClosure as! ThinToThickFunctionInst).referencedFunction!
+    context.notifyNewFunction(function: specializedFunction, derivedFrom: callee)
 
-    if closureCallee.specializationLevel > specializationLevelLimit {
-      continue
-    }
+    return specializedFunction
+  }
 
-    if haveUsedReabstraction {
-      markConvertedAndReabstractedClosuresAsUsed(rootClosure: rootClosure, convertedAndReabstractedClosure: use.value, 
-                                                 convertedAndReabstractedClosures: &convertedAndReabstractedClosures)
-    }
-    
-    if callSiteMap[pai] == nil {
-      callSiteMap.insert(key: pai, value: CallSite(applySite: pai))
-    }
 
-    intermediateClosureArgDescriptorData
-      .append((applySite: pai, closureArgIndex: closureArgumentIndex, paramInfo: closureParamInfo))
-  }
+  private func getSpecializedFunctionName(_ context: FunctionPassContext) -> String {
+    var visited = Dictionary<Closure, Int>()
 
-  return intermediateClosureArgDescriptorData
-}
+    let argumentManglings = closureArguments.map { (argOp, closure) in
+      let argIdx = apply.calleeArgumentIndex(of: argOp)!
+      if let prevArgIdx = visited[closure] {
 
-/// Finalizes the call sites for a given root closure by adding a corresponding `ClosureArgDescriptor`
-/// to all call sites where the closure is ultimately passed as an argument.
-private func finalizeCallSites(for rootClosure: SingleValueInstruction, in callSiteMap: inout CallSiteMap, 
-                               rootClosurePossibleLiveRange: InstructionRange, 
-                               intermediateClosureArgDescriptorData: [IntermediateClosureArgDescriptorDatum], 
-                               _ context: FunctionPassContext) 
-{
-  let closureInfo = ClosureInfo(closure: rootClosure, lifetimeFrontier: Array(rootClosurePossibleLiveRange.ends))
-
-  for (applySite, closureArgumentIndex, parameterInfo) in intermediateClosureArgDescriptorData {
-    guard var callSite = callSiteMap[applySite] else {
-      fatalError("While finalizing call sites, call site descriptor not found for call site: \(applySite)!")
+        // If the same closure is passed multiple times to a function, we need to reflect this in the mangling:
+        //
+        //   %3 = function_ref @closure
+        //   %4 = partial_apply %3(%1) : (Int) -> ()
+        //   apply %6(%4, %4)
+        //
+        // sil @specialized_closure_user : (Int) -> () {
+        //
+        // is different than
+        //
+        //   %3 = function_ref @closure
+        //   %4 = partial_apply %3(%1) : (Int) -> ()
+        //   %5 = partial_apply %3(%1) : (Int) -> ()
+        //   apply %6(%4, %5)
+        //
+        // sil @specialized_closure_user : (Int, Int) -> () {
+        //
+        return (argIdx, FunctionPassContext.ClosureArgumentMangling.previousArgumentIndex(prevArgIdx))
+      } else {
+        visited[closure] = argIdx
+        return (argIdx, FunctionPassContext.ClosureArgumentMangling.closure(closure))
+      }
     }
-    let closureArgDesc = ClosureArgDescriptor(closureInfo: closureInfo, closureArgumentIndex: closureArgumentIndex, 
-                                              parameterInfo: parameterInfo)
-    callSite.appendClosureArgDescriptor(closureArgDesc)
-    callSiteMap.update(key: applySite, value: callSite)
+    return context.mangle(withClosureArguments: argumentManglings, from: callee)
   }
-}
 
-private func isClosureApplied(in callee: Function, closureArgIndex index: Int) -> Bool {
-  func inner(_ callee: Function, _ index: Int, _ handledFuncs: inout Set<Function>) -> Bool {
-    let closureArg = callee.argument(at: index)
+  private func getSpecializedParameters() -> [ParameterInfo] {
+    var specializedParamInfoList: [ParameterInfo] = []
 
-    for use in closureArg.uses {
-      if let fai = use.instruction as? ApplySite {
-        if fai.callee == closureArg {
-          return true
-        }
+    // Start by adding all original parameters except for the closure parameters.
+    let firstParamIndex = callee.argumentConventions.firstParameterIndex
+    for (index, paramInfo) in callee.convention.parameters.enumerated() {
+      let argIndex = index + firstParamIndex
+      if !closureArguments.contains(where: { apply.calleeArgumentIndex(of: $0.0) == argIndex}) {
+        specializedParamInfoList.append(paramInfo)
+      }
+    }
 
-        if let faiCallee = fai.referencedFunction,
-           !faiCallee.blocks.isEmpty,
-           handledFuncs.insert(faiCallee).inserted,
-           handledFuncs.count <= recursionBudget
-        {
-          if inner(faiCallee, fai.calleeArgumentIndex(of: use)!, &handledFuncs) {
-            return true
-          }
-        }
+    // Now, append parameters captured by each of the root closures.
+    for partialApply in rootClosures {
+      let closureConvention = partialApply.functionConvention
+      let unappliedArgumentCount = partialApply.unappliedArgumentCount - closureConvention.indirectSILResultCount
+
+      for paramInfo in closureConvention.parameters[unappliedArgumentCount...] {
+        let newParamInfo = paramInfo.withSpecializedConvention(for: partialApply, in: callee)
+        specializedParamInfoList.append(newParamInfo)
       }
     }
 
-    return false
+    return specializedParamInfoList
   }
 
-  // Limit the number of recursive calls to not go into exponential behavior in corner cases.
-  let recursionBudget = 8
-  var handledFuncs: Set<Function> = []
-  return inner(callee, index, &handledFuncs)
-}
+  private func cloneAndSpecializeFunctionBody(using cloner: inout Cloner) {
+    addFunctionArgumentsWithoutClosures(using: &cloner)
 
-/// Marks any converted/reabstracted closures, corresponding to a given root closure as used. We do not want to 
-/// look at such closures separately as during function specialization they will be handled as part of the root closure. 
-private func markConvertedAndReabstractedClosuresAsUsed(rootClosure: Value, convertedAndReabstractedClosure: Value, 
-                                                        convertedAndReabstractedClosures: inout InstructionSet) 
-{
-  if convertedAndReabstractedClosure != rootClosure {
-    switch convertedAndReabstractedClosure {
-    case let pai as PartialApplyInst:
-      convertedAndReabstractedClosures.insert(pai)
-      return 
-        markConvertedAndReabstractedClosuresAsUsed(rootClosure: rootClosure, 
-                                                   convertedAndReabstractedClosure: pai.arguments[0], 
-                                                   convertedAndReabstractedClosures: &convertedAndReabstractedClosures)
-    case let cvt as ConvertFunctionInst:
-      convertedAndReabstractedClosures.insert(cvt)
-      return 
-        markConvertedAndReabstractedClosuresAsUsed(rootClosure: rootClosure, 
-                                                   convertedAndReabstractedClosure: cvt.fromFunction,
-                                                   convertedAndReabstractedClosures: &convertedAndReabstractedClosures)
-    case let cvt as ConvertEscapeToNoEscapeInst:
-      convertedAndReabstractedClosures.insert(cvt)
-      return 
-        markConvertedAndReabstractedClosuresAsUsed(rootClosure: rootClosure, 
-                                                   convertedAndReabstractedClosure: cvt.fromFunction,
-                                                   convertedAndReabstractedClosures: &convertedAndReabstractedClosures)
-    case let mdi as MarkDependenceInst:
-      convertedAndReabstractedClosures.insert(mdi)
-      return 
-        markConvertedAndReabstractedClosuresAsUsed(rootClosure: rootClosure, convertedAndReabstractedClosure: mdi.value,
-                                                   convertedAndReabstractedClosures: &convertedAndReabstractedClosures)
-    default:
-      log("Parent function of callSite: \(rootClosure.parentFunction)")
-      log("Root closure: \(rootClosure)")
-      log("Converted/reabstracted closure: \(convertedAndReabstractedClosure)")
-      fatalError("While marking converted/reabstracted closures as used, found unexpected instruction: \(convertedAndReabstractedClosure)")
+    for rootClosure in rootClosures {
+      addFunctionArgumentsForCaptures(of: rootClosure, using: &cloner)
     }
-  }
-}
 
-private extension SpecializationCloner {
-  func cloneAndSpecializeFunctionBody(using callSite: CallSite) {
-    self.cloneEntryBlockArgsWithoutOrigClosures(usingOrigCalleeAt: callSite)
+    let clonedClosureArguments = cloneClosures(using: &cloner)
 
-    let (allSpecializedEntryBlockArgs, closureArgIndexToAllClonedReleasableClosures) = cloneAllClosures(at: callSite)
+    cloner.cloneFunctionBody(from: callee)
 
-    self.cloneFunctionBody(from: callSite.applyCallee, entryBlockArguments: allSpecializedEntryBlockArgs)
-
-    self.insertCleanupCodeForClonedReleasableClosures(
-      from: callSite, closureArgIndexToAllClonedReleasableClosures: closureArgIndexToAllClonedReleasableClosures)
+    addMissingDestroysAtFunctionExits(for: clonedClosureArguments, cloner.context)
   }
 
-  private func cloneEntryBlockArgsWithoutOrigClosures(usingOrigCalleeAt callSite: CallSite) {
-    let originalEntryBlock = callSite.applyCallee.entryBlock
-    let clonedFunction = self.cloned
-    let clonedEntryBlock = self.entryBlock
-
-    originalEntryBlock.arguments
-      .enumerated()
-      .filter { index, _ in !callSite.hasClosureArg(at: index) }
-      .forEach { _, arg in
-        let clonedEntryBlockArgType = arg.type.getLoweredType(in: clonedFunction)
-        let clonedEntryBlockArg = clonedEntryBlock.addFunctionArgument(type: clonedEntryBlockArgType, self.context)
-        clonedEntryBlockArg.copyFlags(from: arg as! FunctionArgument)
-      }
+  private func addFunctionArgumentsWithoutClosures(using cloner: inout Cloner) {
+    let clonedEntryBlock = cloner.getOrCreateEntryBlock()
+
+    for originalArg in callee.arguments where !isClosureArgument(calleeArgument: originalArg) {
+      let argType = originalArg.type.getLoweredType(in: cloner.targetFunction)
+      let clonedArg = clonedEntryBlock.addFunctionArgument(type: argType, cloner.context)
+      clonedArg.copyFlags(from: originalArg, cloner.context)
+      cloner.recordFoldedValue(originalArg, mappedTo: clonedArg)
+    }
   }
 
-  /// Clones all closures, originally passed to the callee at the given callSite, into the specialized function.
-  ///
-  /// Returns the following -
-  /// - allSpecializedEntryBlockArgs: Complete list of entry block arguments for the specialized function. This includes
-  ///   the original arguments to the function (minus the closure arguments) and the arguments representing the values
-  ///   originally captured by the skipped closure arguments.
-  ///
-  /// - closureArgIndexToAllClonedReleasableClosures: Mapping from a closure's argument index at `callSite` to the list
-  ///   of corresponding releasable closures cloned into the specialized function. We have a "list" because we clone
-  ///   "closure chains", which consist of a "root" closure and its conversions/reabstractions. This map is used to
-  ///   generate cleanup code for the cloned closures in the specialized function.
-  private func cloneAllClosures(at callSite: CallSite) 
-    -> (allSpecializedEntryBlockArgs: [Value], 
-        closureArgIndexToAllClonedReleasableClosures: [Int: [SingleValueInstruction]]) 
-  {
-    func entryBlockArgsWithOrigClosuresSkipped() -> [Value?] {
-      var clonedNonClosureEntryBlockArgs = self.entryBlock.arguments.makeIterator()
-
-      return callSite.applyCallee
-        .entryBlock
-        .arguments
-        .enumerated()
-        .reduce(into: []) { result, origArgTuple in
-          let (index, _) = origArgTuple
-          if !callSite.hasClosureArg(at: index) {
-            result.append(clonedNonClosureEntryBlockArgs.next())
-          } else {
-            result.append(Optional.none)
-          }
-        }
+  private func addFunctionArgumentsForCaptures(of closure: PartialApplyInst, using cloner: inout Cloner) {
+    for originalClosureArg in closure.arguments {
+      let capturedArg = cloner.targetFunction.entryBlock.addFunctionArgument(
+        type: originalClosureArg.type.getLoweredType(in: cloner.targetFunction),
+        cloner.context)
+      if !cloner.isCloned(value: originalClosureArg) {
+        cloner.recordFoldedValue(originalClosureArg, mappedTo: capturedArg)
+      }
     }
+  }
 
-    var entryBlockArgs: [Value?] = entryBlockArgsWithOrigClosuresSkipped()
-    var closureArgIndexToAllClonedReleasableClosures: [Int: [SingleValueInstruction]] = [:]
+  private func cloneClosures(using cloner: inout Cloner) -> [Value] {
+    return closureArguments.map { (closureArgOp, _) in
+      let clonedArg = cloner.cloneRecursively(value: closureArgOp.value)
 
-    for closureArgDesc in callSite.closureArgDescriptors {
-      let (finalClonedReabstractedClosure, allClonedReleasableClosures) =
-        self.cloneClosureChain(representedBy: closureArgDesc, at: callSite)
+      let originalArg = apply.calleeArgument(of: closureArgOp, in: callee)!
+      cloner.recordFoldedValue(originalArg, mappedTo: clonedArg)
 
-      entryBlockArgs[closureArgDesc.closureArgIndex] = finalClonedReabstractedClosure
-      closureArgIndexToAllClonedReleasableClosures[closureArgDesc.closureArgIndex] = allClonedReleasableClosures
+      return clonedArg
     }
-
-    return (entryBlockArgs.map { $0! }, closureArgIndexToAllClonedReleasableClosures)
   }
 
-  private func cloneClosureChain(representedBy closureArgDesc: ClosureArgDescriptor, at callSite: CallSite) 
-    -> (finalClonedReabstractedClosure: SingleValueInstruction, allClonedReleasableClosures: [SingleValueInstruction]) 
-  {
-    let (origToClonedValueMap, capturedArgRange) = self.addEntryBlockArgs(forValuesCapturedBy: closureArgDesc)
-    let clonedFunction = self.cloned
-    let clonedEntryBlock = self.entryBlock
-    let clonedClosureArgs = Array(clonedEntryBlock.arguments[capturedArgRange])
+  func rewriteApply(for specializedFunction: Function, _ context: FunctionPassContext) {
+    insertCompensatingDestroysForOwnedClosureArguments(context)
 
-    let builder = clonedEntryBlock.instructions.isEmpty
-                  ? Builder(atStartOf: clonedFunction, self.context)
-                  : Builder(atEndOf: clonedEntryBlock, location: clonedEntryBlock.instructions.last!.location, self.context)
+    let newApplyArgs = getNewApplyArguments(context)
 
-    let clonedRootClosure = builder.cloneRootClosure(representedBy: closureArgDesc, capturedArguments: clonedClosureArgs)
+    let builder = Builder(before: apply, context)
+    let funcRef = builder.createFunctionRef(specializedFunction)
 
-    let (finalClonedReabstractedClosure, releasableClonedReabstractedClosures) = 
-      builder.cloneRootClosureReabstractions(rootClosure: closureArgDesc.closure, clonedRootClosure: clonedRootClosure,
-                                             reabstractedClosure: callSite.appliedArgForClosure(at: closureArgDesc.closureArgIndex)!,
-                                             origToClonedValueMap: origToClonedValueMap,
-                                             self.context)
+    switch apply {
+    case let oldPartialApply as PartialApplyInst:
+      let newPartialApply = builder.createPartialApply(
+        function: funcRef, substitutionMap: SubstitutionMap(),
+        capturedArguments: newApplyArgs, calleeConvention: oldPartialApply.calleeConvention,
+        hasUnknownResultIsolation: oldPartialApply.hasUnknownResultIsolation,
+        isOnStack: oldPartialApply.isOnStack)
+      oldPartialApply.replace(with: newPartialApply, context)
 
-    let allClonedReleasableClosures = [clonedRootClosure] + releasableClonedReabstractedClosures
-    return (finalClonedReabstractedClosure, allClonedReleasableClosures)
-  }
+    case let oldApply as ApplyInst:
+      let newApply = builder.createApply(function: funcRef, SubstitutionMap(), arguments: newApplyArgs,
+                                         isNonThrowing: oldApply.isNonThrowing,
+                                         isNonAsync: oldApply.isNonAsync)
+      oldApply.replace(with: newApply, context)
 
-  private func addEntryBlockArgs(forValuesCapturedBy closureArgDesc: ClosureArgDescriptor) 
-    -> (origToClonedValueMap: [HashableValue: Value], capturedArgRange: Range<Int>) 
-  {
-    var origToClonedValueMap: [HashableValue: Value] = [:]
-    let clonedFunction = self.cloned
-    let clonedEntryBlock = self.entryBlock
-
-    let capturedArgRangeStart = clonedEntryBlock.arguments.count
-      
-    for arg in closureArgDesc.arguments {
-      let capturedArg = clonedEntryBlock.addFunctionArgument(type: arg.type.getLoweredType(in: clonedFunction), 
-                                                              self.context)
-      origToClonedValueMap[arg] = capturedArg
-    }
+    case let oldTryApply as TryApplyInst:
+      builder.createTryApply(function: funcRef, SubstitutionMap(), arguments: newApplyArgs,
+                             normalBlock: oldTryApply.normalBlock, errorBlock: oldTryApply.errorBlock,
+                             isNonAsync: oldTryApply.isNonAsync)
+      context.erase(instruction: oldTryApply)
 
-    let capturedArgRangeEnd = clonedEntryBlock.arguments.count
-    let capturedArgRange = capturedArgRangeStart == capturedArgRangeEnd 
-                           ? 0..<0 
-                           : capturedArgRangeStart..<capturedArgRangeEnd
+    case let oldBeginApply as BeginApplyInst:
+      let newApply = builder.createBeginApply(function: funcRef, SubstitutionMap(), arguments: newApplyArgs,
+                                              isNonThrowing: oldBeginApply.isNonThrowing,
+                                              isNonAsync: oldBeginApply.isNonAsync)
+      oldBeginApply.replace(with: newApply, context)
+    default:
+      fatalError("unknown apply")
+    }
+  }
 
-    return (origToClonedValueMap, capturedArgRange)
+  private func insertCompensatingDestroysForOwnedClosureArguments(_ context: FunctionPassContext) {
+    let builder = Builder(before: apply, context)
+    for (argOp, _) in closureArguments where argOp.endsLifetime {
+      builder.createDestroyValue(operand: argOp.value)
+    }
   }
 
-  private func insertCleanupCodeForClonedReleasableClosures(from callSite: CallSite, 
-                                                            closureArgIndexToAllClonedReleasableClosures: [Int: [SingleValueInstruction]])
-  {
-    for closureArgDesc in callSite.closureArgDescriptors {
-      let allClonedReleasableClosures = closureArgIndexToAllClonedReleasableClosures[closureArgDesc.closureArgIndex]!
-
-      // Insert a `destroy_value`, for all releasable closures, in all reachable exit BBs if the closure was passed as a
-      // guaranteed parameter or its type was noescape+thick. This is b/c the closure was passed at +0 originally and we
-      // need to balance the initial increment of the newly created closure(s).
-      if closureArgDesc.isClosureGuaranteed || closureArgDesc.parameterInfo.isTrivialNoescapeClosure,
-         !allClonedReleasableClosures.isEmpty
-      {
-        for exitBlock in callSite.reachableExitBBsInCallee {
-          let clonedExitBlock = self.getClonedBlock(for: exitBlock)
-          
-          let terminator = clonedExitBlock.terminator is UnreachableInst
-                           ? clonedExitBlock.terminator.previous!
-                           : clonedExitBlock.terminator
-
-          let builder = Builder(before: terminator, self.context)
-
-          for closure in allClonedReleasableClosures {
-            if let pai = closure as? PartialApplyInst {
-              builder.destroyPartialApply(pai: pai, self.context)  
-            }
-          }
+  private func getNewApplyArguments(_ context: FunctionPassContext) -> [Value] {
+    let newCapturedArguments = rootClosures.flatMap { partialApply in
+      partialApply.arguments.map { capturedArg in
+        if partialApply.isOnStack || capturedArg.ownership == .none {
+          // Non-escaping closures don't consume their captures. Therefore we pass them also as "guaranteed"
+          // arguments to the specialized function.
+          // Note that because the non-escaping closure was passed to the original function, this guarantees
+          // that the lifetime of the captured arguments also extend to at least the apply of the function.
+          capturedArg
+        } else {
+          // Escaping closures consume their captures. Therefore we pass them as "owned" arguments to the
+          // specialized function.
+          capturedArg.copy(at: partialApply, andMakeAvailableIn: apply.parentBlock, context)
         }
       }
     }
-
-    if (self.context.needFixStackNesting) {
-      self.cloned.fixStackNesting(self.context)
-    }
+    return nonClosureArguments.values + newCapturedArguments
   }
-}
 
-private extension [HashableValue: Value] {
-  subscript(key: Value) -> Value? {
-    get {
-      self[key.hashable]
-    }
-    set {
-      self[key.hashable] = newValue
-    }
-  }
-}
+  func uniqueCaptureArguments(_ context: FunctionPassContext) {
+    let builder = Builder(before: apply, context)
 
-private extension CallSite {
-  enum NewApplyArg {
-    case Original(Value)
-    // TODO: This can be simplified in OSSA. We can just do a copy_value for everything - except for addresses???
-    case PreviouslyCaptured(
-      value: Value, needsRetain: Bool, parentClosureArgIndex: Int)
-
-    var value: Value {
-      switch self {
-      case let .Original(originalArg):
-        return originalArg
-      case let .PreviouslyCaptured(capturedArg, _, _):
-        return capturedArg
+    // Insert identity cast instructions for all closure arguments to make them unique. We could use any kind
+    // of forwarding instruction - we'll delete them afterwards, anyway.
+    //
+    //   %4 = partial_apply %3(%1, %1) : (Int, Int) -> ()  // %1 is captured twice
+    // ->
+    //   %2 = unchecked_value_cast %1
+    //   %3 = unchecked_value_cast %1
+    //   %4 = partial_apply %3(%2, %3) : (Int, Int) -> ()  // all arguments are unique values now!
+    //
+    for closure in rootClosures {
+      for argOp in closure.argumentOperands {
+        let cast = builder.createUncheckedValueCast(from: argOp.value, to: argOp.value.type)
+        argOp.set(to: cast, context)
       }
     }
   }
 
-  func getArgumentsForSpecializedApply(of specializedCallee: Function) -> [NewApplyArg]
-  {
-    var newApplyArgs: [NewApplyArg] = []
-
-    // Original arguments
-    for (applySiteIndex, arg) in self.applySite.arguments.enumerated() {
-      let calleeArgIndex = self.applySite.unappliedArgumentCount + applySiteIndex
-      if !self.hasClosureArg(at: calleeArgIndex) {
-        newApplyArgs.append(.Original(arg))
+  func unUniqueCaptureArguments(_ context: FunctionPassContext) {
+    // Remove the inserted identity casts again.
+    for closure in rootClosures {
+      for argOp in closure.argumentOperands {
+        let cast = argOp.value as! UncheckedValueCastInst
+        cast.replace(with: cast.fromValue, context)
       }
     }
+  }
 
-    // Previously captured arguments
-    for closureArgDesc in self.closureArgDescriptors {
-      for (applySiteIndex, capturedArg) in closureArgDesc.arguments.enumerated() {
-        let needsRetain = closureArgDesc.isCapturedArgNonTrivialObjectType(applySiteIndex: applySiteIndex, 
-                                                                           specializedCallee: specializedCallee)
-
-        newApplyArgs.append(.PreviouslyCaptured(value: capturedArg, needsRetain: needsRetain, 
-                                                parentClosureArgIndex: closureArgDesc.closureArgIndex))
+  func deleteDeadClosures(_ context: FunctionPassContext) {
+    for  (_, closure) in closureArguments where !closure.isDeleted {
+      if context.tryDeleteDeadClosure(closure: closure) {
+        context.notifyInvalidatedStackNesting()
       }
     }
-
-    return newApplyArgs
   }
-}
-
-private extension ClosureArgDescriptor {
-  func isCapturedArgNonTrivialObjectType(applySiteIndex: Int, specializedCallee: Function) -> Bool {
-    precondition(self.closure is PartialApplyInst, "ClosureArgDescriptor is not for a partial_apply closure!")
 
-    let capturedArg = self.arguments[applySiteIndex]
-    let pai = self.closure as! PartialApplyInst
-    let capturedArgIndexInCallee = applySiteIndex + pai.unappliedArgumentCount
-    let capturedArgConvention = self.callee.argumentConventions[capturedArgIndexInCallee]
+  private var nonClosureArguments: LazyFilterSequence<OperandArray> {
+    apply.argumentOperands.lazy.filter{ argOp in !closureArguments.contains{ $0.0 == argOp } }
+  }
 
-    return !capturedArg.type.isTrivial(in: specializedCallee) && 
-           !capturedArgConvention.isAllowedIndirectConvForClosureSpec
+  private func isClosureArgument(calleeArgument: FunctionArgument) -> Bool {
+    closureArguments.contains { apply.calleeArgument(of: $0.0, in: callee) == calleeArgument }
   }
 }
 
-private extension Builder {
-  func cloneRootClosure(representedBy closureArgDesc: ClosureArgDescriptor, capturedArguments: [Value]) 
-    -> SingleValueInstruction 
-  {
-    let function = self.createFunctionRef(closureArgDesc.callee)
+private func isClosureApplied(_ closure: Value) -> Bool {
+  var handledFuncs: Set<Function> = []
+  return checkRecursivelyIfClosureIsApplied(closure, &handledFuncs)
+}
 
-    if let pai = closureArgDesc.closure as? PartialApplyInst {
-      return self.createPartialApply(function: function, substitutionMap: SubstitutionMap(), 
-                                     capturedArguments: capturedArguments, calleeConvention: pai.calleeConvention,
-                                     hasUnknownResultIsolation: pai.hasUnknownResultIsolation, 
-                                     isOnStack: pai.isOnStack)
-    } else {
-      return self.createThinToThickFunction(thinFunction: function, resultType: closureArgDesc.closure.type)
-    }
-  }
+private func checkRecursivelyIfClosureIsApplied(_ closure: Value, _ handledFuncs: inout Set<Function>) -> Bool {
+  for use in closure.uses {
+    switch use.instruction {
 
-  func cloneRootClosureReabstractions(rootClosure: Value, clonedRootClosure: Value, reabstractedClosure: Value,
-                                      origToClonedValueMap: [HashableValue: Value], _ context: FunctionPassContext) 
-    -> (finalClonedReabstractedClosure: SingleValueInstruction, releasableClonedReabstractedClosures: [PartialApplyInst]) 
-  {
-    func inner(_ rootClosure: Value, _ clonedRootClosure: Value, _ reabstractedClosure: Value, 
-               _ releasableClonedReabstractedClosures: inout [PartialApplyInst], 
-               _ origToClonedValueMap: inout [HashableValue: Value]) -> Value {
-      switch reabstractedClosure {
-        case let reabstractedClosure where reabstractedClosure == rootClosure:
-          origToClonedValueMap[reabstractedClosure] = clonedRootClosure
-          return clonedRootClosure
-        
-        case let cvt as ConvertFunctionInst:
-          let toBeReabstracted = inner(rootClosure, clonedRootClosure, cvt.fromFunction, 
-                                       &releasableClonedReabstractedClosures, &origToClonedValueMap)
-          let reabstracted = self.createConvertFunction(originalFunction: toBeReabstracted, resultType: cvt.type, 
-                                                        withoutActuallyEscaping: cvt.withoutActuallyEscaping)
-          origToClonedValueMap[cvt] = reabstracted
-          return reabstracted
-        
-        case let cvt as ConvertEscapeToNoEscapeInst:
-          let toBeReabstracted = inner(rootClosure, clonedRootClosure, cvt.fromFunction, 
-                                       &releasableClonedReabstractedClosures, &origToClonedValueMap)
-          let reabstracted = self.createConvertEscapeToNoEscape(originalFunction: toBeReabstracted, resultType: cvt.type,
-                                                                isLifetimeGuaranteed: true)
-          origToClonedValueMap[cvt] = reabstracted
-          return reabstracted
-
-        case let pai as PartialApplyInst:
-          let toBeReabstracted = inner(rootClosure, clonedRootClosure, pai.arguments[0], 
-                                       &releasableClonedReabstractedClosures, &origToClonedValueMap)
-          
-          guard let function = pai.referencedFunction else {
-            log("Parent function of callSite: \(rootClosure.parentFunction)")
-            log("Root closure: \(rootClosure)")
-            log("Unsupported reabstraction closure: \(pai)")
-            fatalError("Encountered unsupported reabstraction (via partial_apply) of root closure!")
-          }
-
-          let fri = self.createFunctionRef(function)
-          let reabstracted = self.createPartialApply(function: fri, substitutionMap: SubstitutionMap(), 
-                                                     capturedArguments: [toBeReabstracted], 
-                                                     calleeConvention: pai.calleeConvention, 
-                                                     hasUnknownResultIsolation: pai.hasUnknownResultIsolation, 
-                                                     isOnStack: pai.isOnStack)
-          releasableClonedReabstractedClosures.append(reabstracted)
-          origToClonedValueMap[pai] = reabstracted
-          return reabstracted
-        
-        case let mdi as MarkDependenceInst:
-          let toBeReabstracted = inner(rootClosure, clonedRootClosure, mdi.value, &releasableClonedReabstractedClosures, 
-                                       &origToClonedValueMap)
-          let base = origToClonedValueMap[mdi.base]!
-          let reabstracted = self.createMarkDependence(value: toBeReabstracted, base: base, kind: .Escaping)
-          origToClonedValueMap[mdi] = reabstracted
-          return reabstracted
-        
-        default:
-          log("Parent function of callSite: \(rootClosure.parentFunction)")
-          log("Root closure: \(rootClosure)")
-          log("Converted/reabstracted closure: \(reabstractedClosure)")
-          fatalError("Encountered unsupported reabstraction of root closure: \(reabstractedClosure)")
+    case let apply as FullApplySite:
+      if apply.callee == closure {
+        return true
       }
-    }
-
-    var releasableClonedReabstractedClosures: [PartialApplyInst] = []
-    var origToClonedValueMap = origToClonedValueMap
-    let finalClonedReabstractedClosure = inner(rootClosure, clonedRootClosure, reabstractedClosure, 
-                                               &releasableClonedReabstractedClosures, &origToClonedValueMap)
-    return (finalClonedReabstractedClosure as! SingleValueInstruction, releasableClonedReabstractedClosures)
-  }
-
-  func destroyPartialApply(pai: PartialApplyInst, _ context: FunctionPassContext){
-    // TODO: Support only OSSA instructions once the OSSA elimination pass is moved after all function optimization 
-    // passes.
-
-    if pai.isOnStack {
-      // for arg in pai.arguments {
-      //   self.createDestroyValue(operand: arg)
-      // }
-      // self.createDestroyValue(operand: pai)
-
-      if pai.parentFunction.hasOwnership {
-      // Under OSSA, the closure acts as an owned value whose lifetime is a borrow scope for the captures, so we need to
-      // end the borrow scope before ending the lifetimes of the captures themselves.
-        self.createDestroyValue(operand: pai)
-        self.destroyCapturedArgs(for: pai)
-      } else {
-        self.destroyCapturedArgs(for: pai)
-        self.createDeallocStack(pai)
-        context.notifyInvalidatedStackNesting()
+      let recursionBudget = 8
+
+      // Recurse into called function
+      if let callee = apply.referencedFunction,
+         callee.isDefinition,
+         handledFuncs.insert(callee).inserted,
+         handledFuncs.count <= recursionBudget,
+         let calleeArg = apply.calleeArgument(of: use, in: callee)
+      {
+        if checkRecursivelyIfClosureIsApplied(calleeArg, &handledFuncs) {
+          return true
+        }
       }
-    } else {
-      if pai.parentFunction.hasOwnership {
-        self.createDestroyValue(operand: pai)
-      } else {
-        self.createReleaseValue(operand: pai)
+
+    case is CopyValueInst, is MoveValueInst:
+      if checkRecursivelyIfClosureIsApplied(use.instruction as! SingleValueInstruction, &handledFuncs) {
+        return true
       }
+
+    default:
+      break
     }
   }
+
+  return false
 }
 
-private extension FunctionConvention {
-  func getSpecializedParameters(basedOn callSite: CallSite) -> [ParameterInfo] {
-    let applySiteCallee = callSite.applyCallee
-    var specializedParamInfoList: [ParameterInfo] = []
+/// Add destroys for values which are not consumed, yet.
+/// There are two cases of values for which we need this:
+/// 1. guaranteed closure arguments
+/// 2. operands of copies at the call site
+///
+/// ```
+///   %1 = partial_apply %closure   // is cloned to the specialized function
+///   %2 = copy_value %1            // is cloned to the specialized function
+///   apply %function(%2) : (@guaranteed () -> ()) -> ()
+///   destroy_value %1
+///
+/// sil @specializedFunction() -> () {
+/// bb0:
+///   %1 = partial_apply %closure
+///   %2 = copy_value %1
+///   ... // body
+///   destroy_value %2              // case 1: destroy for the guaranteed closure argument
+///   destroy_value %1              // case 2: destroy for the operand of the copy
+///   return
+/// ```
+private func addMissingDestroysAtFunctionExits(for clonedArguments: [Value], _ context: FunctionPassContext) {
+  var needDestroy = ValueWorklist(context)
+  defer { needDestroy.deinitialize() }
 
-    // Start by adding all original parameters except for the closure parameters.
-    let firstParamIndex = applySiteCallee.argumentConventions.firstParameterIndex
-    for (index, paramInfo) in applySiteCallee.convention.parameters.enumerated() {
-      let argIndex = index + firstParamIndex
-      if !callSite.hasClosureArg(at: argIndex) {
-        specializedParamInfoList.append(paramInfo)
-      }
-    }
+  for clonedArg in clonedArguments {
+    findValuesWhichNeedDestroyRecursively(value: clonedArg, needDestroy: &needDestroy)
+  }
 
-    // Now, append parameters captured by each of the original closure parameter.
-    //
-    // Captured parameters are always appended to the function signature. If the argument type of the captured 
-    // parameter in the callee is:
-    // - direct and trivial, pass the new parameter as Direct_Unowned.
-    // - direct and non-trivial, pass the new parameter as Direct_Owned.
-    // - indirect, pass the new parameter using the same parameter convention as in
-    //   the original closure.
-    for closureArgDesc in callSite.closureArgDescriptors {
-      if let closure = closureArgDesc.closure as? PartialApplyInst {
-        let closureCallee = closureArgDesc.callee
-        let closureCalleeConvention = closureCallee.convention
-        let unappliedArgumentCount = closure.unappliedArgumentCount - closureCalleeConvention.indirectSILResultCount
-
-        let prevCapturedParameters =
-          closureCalleeConvention
-          .parameters[unappliedArgumentCount...]
-          .enumerated()
-          .map { index, paramInfo in
-            let argIndexOfParam = closureCallee.argumentConventions.firstParameterIndex + unappliedArgumentCount + index
-            let argType = closureCallee.argumentTypes[argIndexOfParam]
-            return paramInfo.withSpecializedConvention(isArgTypeTrivial: argType.isTrivial(in: closureCallee))
-          }
-
-        specializedParamInfoList.append(contentsOf: prevCapturedParameters)
-      }
+  while let valueToDestroy = needDestroy.pop() {
+    Builder.insertCleanupAtFunctionExits(of: valueToDestroy.parentFunction, context) { builder in
+      builder.createDestroyValue(operand: valueToDestroy)
     }
-
-    return specializedParamInfoList
   }
 }
 
-private extension ParameterInfo {
-  func withSpecializedConvention(isArgTypeTrivial: Bool) -> Self {
-    let specializedParamConvention = self.convention.isAllowedIndirectConvForClosureSpec
-      ? self.convention
-      : isArgTypeTrivial ? ArgumentConvention.directUnowned : ArgumentConvention.directOwned
-
-    return ParameterInfo(type: self.type, convention: specializedParamConvention, options: self.options, 
-                         hasLoweredAddresses: self.hasLoweredAddresses)
+private func findValuesWhichNeedDestroyRecursively(value: Value, needDestroy: inout ValueWorklist) {
+  if let svi = value as? SingleValueInstruction {
+    for op in svi.operands {
+      findValuesWhichNeedDestroyRecursively(value: op.value, needDestroy: &needDestroy)
+    }
   }
-
-  var isTrivialNoescapeClosure: Bool {
-    SILFunctionType_isTrivialNoescape(type.bridged)
+  if value.ownership == .owned && value.uses.endingLifetime.isEmpty {
+    needDestroy.pushIfNotVisited(value)
   }
 }
 
-private extension ArgumentConvention {
-  var isAllowedIndirectConvForClosureSpec: Bool {
-    switch self {
-    case .indirectInout, .indirectInoutAliasable:
-      return true
-    default:
-      return false
+private extension ParameterInfo {
+  func withSpecializedConvention(for partialApply: PartialApplyInst, in callee: Function) -> Self {
+    let argType = type.loweredType(in: partialApply.parentFunction)
+    let specializedParamConvention = if self.convention.isIndirect {
+      self.convention
+    } else {
+      if argType.isTrivial(in: callee) {
+        ArgumentConvention.directUnowned
+      } else {
+        if partialApply.isOnStack {
+          ArgumentConvention.directGuaranteed
+        } else {
+          ArgumentConvention.directOwned
+        }
+      }
     }
+
+    return ParameterInfo(
+      type: self.type, convention: specializedParamConvention, options: self.options,
+      hasLoweredAddresses: self.hasLoweredAddresses)
   }
 }
 
@@ -1112,10 +749,10 @@ private extension PartialApplyInst {
   /// pullback returned from an autodiff VJP
   var isPullbackInResultOfAutodiffVJP: Bool {
     if self.parentFunction.isAutodiffVJP,
-       let use = self.uses.singleUse,
-       let tupleInst = use.instruction as? TupleInst,
-       let returnInst = self.parentFunction.returnInstruction,
-       tupleInst == returnInst.returnedValue
+      let use = self.uses.singleUse,
+      let tupleInst = use.instruction as? TupleInst,
+      let returnInst = self.parentFunction.returnInstruction,
+      tupleInst == returnInst.returnedValue
     {
       return true
     }
@@ -1124,47 +761,25 @@ private extension PartialApplyInst {
   }
 
   var isPartialApplyOfThunk: Bool {
-    if self.numArguments == 1, 
-       let fun = self.referencedFunction,
-       fun.thunkKind == .reabstractionThunk || fun.thunkKind == .thunk,
-       self.arguments[0].type.isLoweredFunction,
-       self.arguments[0].type.isReferenceCounted(in: self.parentFunction) || self.callee.type.isThickFunction
+    if self.numArguments == 1,
+      let fun = self.referencedFunction,
+      fun.thunkKind == .reabstractionThunk || fun.thunkKind == .thunk,
+      self.arguments[0].type.isLoweredFunction,
+      self.arguments[0].type.isReferenceCounted(in: self.parentFunction) || self.callee.type.isThickFunction
     {
       return true
     }
-    
     return false
   }
 
   var hasOnlyInoutIndirectArguments: Bool {
     self.argumentOperands
       .filter { !$0.value.type.isObject }
-      .allSatisfy { self.convention(of: $0)!.isInout } 
-  }
-}
-
-private extension Instruction {
-  var asSupportedClosure: SingleValueInstruction? {
-    switch self {
-    case let tttf as ThinToThickFunctionInst where tttf.callee is FunctionRefInst:
-      return tttf
-    // TODO: figure out what to do with non-inout indirect arguments
-    // https://forums.swift.org/t/non-inout-indirect-types-not-supported-in-closure-specialization-optimization/70826
-    case let pai as PartialApplyInst where pai.callee is FunctionRefInst && pai.hasOnlyInoutIndirectArguments:
-      return pai
-    default:
-      return nil
-    }
+      .allSatisfy { self.convention(of: $0)!.isInout }
   }
 
-  var isSupportedClosure: Bool {
-    asSupportedClosure != nil
-  }
-}
-
-private extension ApplySite {
-  var calleeIsDynamicFunctionRef: Bool {
-    return !(callee is DynamicFunctionRefInst || callee is PreviousDynamicFunctionRefInst)
+  var allArgumentsCanBeCopied: Bool {
+    arguments.allSatisfy { !$0.type.isMoveOnly }
   }
 }
 
@@ -1176,214 +791,3 @@ private extension Function {
     }
   }
 }
-
-// ===================== Utility Types ===================== //
-private struct OrderedDict<Key: Hashable, Value> {
-  private var valueIndexDict: [Key: Int] = [:]
-  private var entryList: [(Key, Value)] = []
-
-  subscript(key: Key) -> Value? {
-    if let index = valueIndexDict[key] {
-      return entryList[index].1
-    }
-    return nil
-  }
-
-  mutating func insert(key: Key, value: Value) {
-    if valueIndexDict[key] == nil {
-      valueIndexDict[key] = entryList.count
-      entryList.append((key, value))
-    }
-  }
-
-  mutating func update(key: Key, value: Value) {
-    if let index = valueIndexDict[key] {
-      entryList[index].1 = value
-    }
-  }
-
-  var keys: LazyMapSequence<Array<(Key, Value)>, Key> {
-    entryList.lazy.map { $0.0 }
-  }
-
-  var values: LazyMapSequence<Array<(Key, Value)>, Value> {
-    entryList.lazy.map { $0.1 }
-  }
-}
-
-private typealias CallSiteMap = OrderedDict<SingleValueInstruction, CallSite>
-
-private extension CallSiteMap {
-  var callSites: [CallSite] {
-    Array(self.values)
-  }
-}
-
-/// Represents all the information required to represent a closure in isolation, i.e., outside of a callsite context
-/// where the closure may be getting passed as an argument.
-///
-/// Composed with other information inside a `ClosureArgDescriptor` to represent a closure as an argument at a callsite.
-private struct ClosureInfo {
-  let closure: SingleValueInstruction
-  let lifetimeFrontier: [Instruction]
-
-  init(closure: SingleValueInstruction, lifetimeFrontier: [Instruction]) {
-    self.closure = closure
-    self.lifetimeFrontier = lifetimeFrontier
-  }
-
-}
-
-/// Represents a closure as an argument at a callsite.
-private struct ClosureArgDescriptor {
-  let closureInfo: ClosureInfo
-  /// The index of the closure in the callsite's argument list.
-  let closureArgumentIndex: Int
-  let parameterInfo: ParameterInfo
-
-  var closure: SingleValueInstruction {
-    closureInfo.closure
-  }
-  var lifetimeFrontier: [Instruction] {
-    closureInfo.lifetimeFrontier
-  }
-
-  var isPartialApplyOnStack: Bool {
-    if let pai = closure as? PartialApplyInst {
-      return pai.isOnStack
-    }
-    return false
-  }
-
-  var callee: Function {
-    if let pai = closure as? PartialApplyInst {
-      return pai.referencedFunction!
-    } else {
-      return (closure as! ThinToThickFunctionInst).referencedFunction!
-    }
-  }
-
-  var location: Location {
-    closure.location
-  }
-
-  var closureArgIndex: Int {
-    closureArgumentIndex
-  }
-
-  var closureParamInfo: ParameterInfo {
-    parameterInfo
-  }
-
-  var numArguments: Int {
-    if let pai = closure as? PartialApplyInst {
-      return pai.numArguments
-    } else {
-      return 0
-    }
-  }
-
-  var arguments: LazyMapSequence<OperandArray, Value> {
-    if let pai = closure as? PartialApplyInst {
-      return pai.arguments
-    }
-
-    return OperandArray.empty.lazy.map { $0.value } as LazyMapSequence<OperandArray, Value>
-  }
-
-  var isClosureGuaranteed: Bool {
-    closureParamInfo.convention.isGuaranteed
-  }
-
-  var isClosureConsumed: Bool {
-    closureParamInfo.convention.isConsumed
-  }
-}
-
-/// Represents a callsite containing one or more closure arguments.
-private struct CallSite {
-  let applySite: ApplySite
-  var closureArgDescriptors: [ClosureArgDescriptor] = []
-
-  init(applySite: ApplySite) {
-    self.applySite = applySite
-  }
-
-  mutating func appendClosureArgDescriptor(_ descriptor: ClosureArgDescriptor) {
-    self.closureArgDescriptors.append(descriptor)
-  }
-
-  var applyCallee: Function {
-    applySite.referencedFunction!
-  }
-
-  var reachableExitBBsInCallee: [BasicBlock] {
-    applyCallee.blocks.filter { $0.isReachableExitBlock }
-  }
-
-  func hasClosureArg(at index: Int) -> Bool {
-    closureArgDescriptors.contains { $0.closureArgumentIndex == index }
-  }
-
-  func closureArgDesc(at index: Int) -> ClosureArgDescriptor? {
-    closureArgDescriptors.first { $0.closureArgumentIndex == index }
-  }
-
-  func appliedArgForClosure(at index: Int) -> Value? {
-    if let closureArgDesc = closureArgDesc(at: index) {
-      return applySite.arguments[closureArgDesc.closureArgIndex - applySite.unappliedArgumentCount]
-    }
-
-    return nil
-  }
-
-  func specializedCalleeName(_ context: FunctionPassContext) -> String {
-    let closureArgs = Array(self.closureArgDescriptors.map { $0.closure })
-    let closureIndices = Array(self.closureArgDescriptors.map { $0.closureArgIndex })
-
-    return context.mangle(withClosureArguments: closureArgs, closureArgIndices: closureIndices, 
-                          from: applyCallee)
-  }
-}
-
-// ===================== Unit tests ===================== //
-
-let gatherCallSitesTest = FunctionTest("closure_specialize_gather_call_sites") { function, arguments, context in
-  print("Specializing closures in function: \(function.name)")
-  print("===============================================")
-  var callSites = gatherCallSites(in: function, context)
-
-  callSites.forEach { callSite in
-    print("PartialApply call site: \(callSite.applySite)")
-    print("Passed in closures: ")
-    for index in callSite.closureArgDescriptors.indices {
-      var closureArgDescriptor = callSite.closureArgDescriptors[index]
-      print("\(index+1). \(closureArgDescriptor.closureInfo.closure)")
-    }
-  }
-  print("\n")
-}
-
-let specializedFunctionSignatureAndBodyTest = FunctionTest(
-  "closure_specialize_specialized_function_signature_and_body") { function, arguments, context in
-
-  var callSites = gatherCallSites(in: function, context)
-
-  for callSite in callSites {
-    let (specializedFunction, _) = getOrCreateSpecializedFunction(basedOn: callSite, context)
-    print("Generated specialized function: \(specializedFunction.name)")
-    print("\(specializedFunction)\n")
-  }
-}
-
-let rewrittenCallerBodyTest = FunctionTest("closure_specialize_rewritten_caller_body") { function, arguments, context in
-  var callSites = gatherCallSites(in: function, context)
-
-  for callSite in callSites {
-    let (specializedFunction, _) = getOrCreateSpecializedFunction(basedOn: callSite, context)
-    rewriteApplyInstruction(using: specializedFunction, callSite: callSite, context)
-
-    print("Rewritten caller body for: \(function.name):")
-    print("\(function)\n")
-  }
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ComputeEscapeEffects.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ComputeEscapeEffects.swift
index 265254bf82035..3b2ab2c5e242c 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ComputeEscapeEffects.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ComputeEscapeEffects.swift
@@ -72,7 +72,7 @@ let computeEscapeEffects = FunctionPass(name: "compute-escape-effects") {
     return
   }
 
-  context.modifyEffects(in: function) { (effects: inout FunctionEffects) in
+  function.modifyEffects(context) { (effects: inout FunctionEffects) in
     effects.escapeEffects.arguments = newEffects
   }
 }
@@ -141,8 +141,8 @@ private func isOperandOfRecursiveCall(_ op: Operand) -> Bool {
   if let applySite = inst as? FullApplySite,
      let callee = applySite.referencedFunction,
      callee == inst.parentFunction,
-     let argIdx = applySite.calleeArgumentIndex(of: op),
-     op.value == callee.arguments[argIdx] {
+     let calleeArg = applySite.calleeArgument(of: op, in: callee),
+     op.value == calleeArg {
     return true
   }
   return false
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ComputeSideEffects.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ComputeSideEffects.swift
index bdc76968e795f..aa5c8ef5ec691 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ComputeSideEffects.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ComputeSideEffects.swift
@@ -37,40 +37,109 @@ let computeSideEffects = FunctionPass(name: "compute-side-effects") {
     return
   }
 
-  if function.effectAttribute != .none {
-    // Don't try to infer side effects if there are defined effect attributes.
-    return
-  }
-
   var collectedEffects = CollectedEffects(function: function, context)
 
-  // First step: collect effects from all instructions.
-  //
+  // Collect effects from all instructions.
   for block in function.blocks {
     for inst in block.instructions {
       collectedEffects.addInstructionEffects(inst)
     }
   }
-
-  // Second step: If an argument has unknown uses, we must add all previously collected
-  // global effects to the argument, because we don't know to which "global" side-effect
-  // instruction the argument might have escaped.
+  // If an argument has unknown uses, we must add all previously collected
+  // global effects to the argument, because we don't know to which "global"
+  // side-effect instruction the argument might have escaped.
   for argument in function.arguments {
     collectedEffects.addEffectsForEscapingArgument(argument: argument)
     collectedEffects.addEffectsForConsumingArgument(argument: argument)
   }
 
+  let globalEffects: SideEffects.GlobalEffects
+  do {
+    let computed = collectedEffects.globalEffects
+
+    // Combine computed global effects with effects defined by the function's effect attribute, if it has one.
+
+    // The defined and computed global effects of a function with an effect attribute should be treated as
+    // worst case global effects of the function.
+    // This means a global effect should only occur iff it is computed AND defined to occur.
+
+    let defined = function.definedGlobalEffects
+
+    globalEffects = SideEffects.GlobalEffects(
+      memory: SideEffects.Memory(read: defined.memory.read && computed.memory.read,
+                                 write: defined.memory.write && computed.memory.write),
+      ownership: SideEffects.Ownership(copy: defined.ownership.copy && computed.ownership.copy,
+                                       destroy: defined.ownership.destroy && computed.ownership.destroy),
+      allocates: defined.allocates && computed.allocates,
+      isDeinitBarrier: defined.isDeinitBarrier && computed.isDeinitBarrier
+    )
+  }
+
+  // Obtain the argument effects of the function.
+  var argumentEffects = collectedEffects.argumentEffects
+
+  // `[readnone]` and `[readonly]` functions can still access the value fields
+  // of their indirect arguments, permitting v** read and write effects. If
+  // additional read or write effects are computed, we can replace.
+  switch function.effectAttribute {
+  case .readNone:
+    for i in (0..<argumentEffects.count) {
+      // Even a `[readnone]` function can read from indirect arguments.
+      if !function.argumentConventions[i].isIndirectIn {
+        argumentEffects[i].read = nil
+      } else if argumentEffects[i].read?.mayHaveClassProjection ?? false {
+        argumentEffects[i].read = SmallProjectionPath(.anyValueFields)
+      }
+
+      // Even a `[readnone]` function can write to indirect results.
+      if !function.argument(at: i).isIndirectResult {
+        argumentEffects[i].write = nil
+      } else if argumentEffects[i].write?.mayHaveClassProjection ?? false {
+        argumentEffects[i].write = SmallProjectionPath(.anyValueFields)
+      }
+
+      argumentEffects[i].copy = nil
+      argumentEffects[i].destroy = nil
+    }
+
+  case .readOnly:
+    for i in (0..<argumentEffects.count) {
+      // Even a `[readonly]` function can write to indirect results.
+      if !function.argument(at: i).isIndirectResult {
+        argumentEffects[i].write = nil
+      } else if argumentEffects[i].write?.mayHaveClassProjection ?? false {
+        argumentEffects[i].write = SmallProjectionPath(.anyValueFields)
+      }
+
+      argumentEffects[i].destroy = nil
+    }
+
+  case .releaseNone:
+    for i in (0..<argumentEffects.count) {
+      // A `[releasenone]` function can do anything except destroy an argument.
+      argumentEffects[i].destroy = nil
+    }
+
+  case .none:
+    // The user makes no additional guarantees about the effects of the function.
+    break
+  }
+
+
   // Don't modify the effects if they didn't change. This avoids sending a change notification
   // which can trigger unnecessary other invalidations.
   if let existingEffects = function.effects.sideEffects,
-     existingEffects.arguments == collectedEffects.argumentEffects,
-     existingEffects.global == collectedEffects.globalEffects {
+     existingEffects.arguments == argumentEffects,
+     existingEffects.global == globalEffects {
     return
   }
 
   // Finally replace the function's side effects.
-  context.modifyEffects(in: function) { (effects: inout FunctionEffects) in
-    effects.sideEffects = SideEffects(arguments: collectedEffects.argumentEffects, global: collectedEffects.globalEffects)
+  function.modifyEffects(context) { (effects: inout FunctionEffects) in
+    let globalEffects = function.isProgramTerminationPoint ?
+      globalEffects.forProgramTerminationPoints
+      : globalEffects
+    effects.sideEffects = SideEffects(arguments: argumentEffects, global: globalEffects)
   }
 }
 
@@ -105,10 +174,10 @@ private struct CollectedEffects {
       addEffects(.read, to: copy.source)
       addEffects(.write, to: copy.destination)
 
-      if !copy.isTakeOfSrc {
+      if !copy.isTakeOfSource {
         addEffects(.copy, to: copy.source)
       }
-      if !copy.isInitializationOfDest {
+      if !copy.isInitializationOfDestination {
         addDestroyEffects(ofAddress: copy.destination)
       }
 
@@ -185,6 +254,11 @@ private struct CollectedEffects {
       // effect, it would not give any significant benefit in any of our current optimizations.
       addEffects(.destroy, to: inst.operands[0].value, fromInitialPath: SmallProjectionPath(.anyValueFields))
 
+    case is ReturnInst:
+      if inst.parentFunction.convention.hasGuaranteedAddressResult {
+        addEffects(.read, to: inst.operands[0].value)
+      }
+
     default:
       if inst.mayRelease {
         globalEffects = .worstEffects
@@ -491,7 +565,7 @@ private struct ArgumentEscapingWalker : ValueDefUseWalker, AddressDefUseWalker {
     case let copy as CopyAddrInst:
       if address == copy.sourceOperand &&
           !address.value.hasTrivialType &&
-          (!function.hasOwnership || copy.isTakeOfSrc) {
+          (!function.hasOwnership || copy.isTakeOfSource) {
         foundTakingLoad = true
       }
       return .continueWalk
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ConstantCapturePropagation.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ConstantCapturePropagation.swift
new file mode 100644
index 0000000000000..1f3abb6e6b1f1
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ConstantCapturePropagation.swift
@@ -0,0 +1,390 @@
+//===--- ConstantCapturePropagation.swift ---------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+import AST
+
+/// Propagates constant closure captures by specializing the partially applied function:
+///
+/// ```
+///   %1 = function_ref @closure
+///   %2 = integer_literal $Builtin.Int64, 27
+///   %3 = partial_apply %1(%2)
+///
+/// sil @closure : $(Builtin.Int64) -> () {
+/// bb0(%0 : $Builtin.Int64):
+///   ...
+/// ```
+/// ->
+/// ```
+///   %1 = function_ref @specialized_closure
+///   %3 = partial_apply %1()
+///
+/// sil @specialized_closure : $() -> () {
+/// bb0:
+///   %0 = integer_literal $Builtin.Int64, 27
+///   ...
+/// ```
+///
+/// Also, optimizes away a `partial_apply` of a thunk to a closure where all partially applied
+/// arguments are dead:
+///
+/// ```
+///   %2 = function_ref @thunk
+///   %3 = partial_apply %2(%1)
+///
+/// sil @thunk : $(T, V) -> () {
+/// bb0(%0 : $T, %1 : $V):        // %1 is dead
+///   %2 = function_ref @closure
+///   %3 = apply %2(%0)           // alive arguments are forwarded 1:1
+///   return %3
+/// }
+/// ```
+/// ->
+/// ```
+///   %2 = function_ref @closure
+///   %3 = thin_to_thick_function %2
+/// ```
+///
+let constantCapturePropagation = FunctionPass(name: "constant-capture-propagation") {
+  (function: Function, context: FunctionPassContext) in
+
+  for inst in function.instructions {
+    guard let partialApply = inst as? PartialApplyInst,
+          // Only support closures which - after generic specialization - are not generic anymore.
+          !partialApply.substitutionMap.replacementTypes.contains(where: { $0.hasArchetype })
+    else {
+      continue
+    }
+
+    if !context.continueWithNextSubpassRun(for: partialApply) {
+      return
+    }
+
+    optimizeClosureWithDeadCaptures(of: partialApply, context)
+
+    if partialApply.isDeleted {
+      continue
+    }
+
+    constantPropagateCaptures(of: partialApply, context)
+  }
+}
+
+private func optimizeClosureWithDeadCaptures(of partialApply: PartialApplyInst, _ context: FunctionPassContext) {
+  if let callee = getSpecializedCalleeWithDeadParams(of: partialApply, context) {
+    rewritePartialApply(partialApply, withSpecialized: callee, arguments: [], context)
+  }
+}
+
+private func constantPropagateCaptures(of partialApply: PartialApplyInst, _ context: FunctionPassContext) {
+  guard let callee = partialApply.referencedFunction,
+        callee.isDefinition,
+        let (constArgs, nonConstArgs) = partialApply.classifyArgumentsForConstness()
+  else {
+    return
+  }
+
+  let specializedName = context.mangle(withConstantCaptureArguments: constArgs.map {
+                                           (partialApply.calleeArgumentIndex(of: $0)!, $0.value)
+                                         },
+                                       from: callee)
+
+  let specializedCallee: Function
+  if let existing = context.lookupFunction(name: specializedName) {
+    specializedCallee = existing
+  } else {
+    specializedCallee = specializeClosure(specializedName: specializedName,
+                                          partialApply: partialApply,
+                                          constantArguments: constArgs, nonConstantArguments: nonConstArgs,
+                                          context)
+  }
+  if !partialApply.isOnStack {
+    // Escaping closures consume their arguments. Therefore we need to destroy the removed argument values.
+    addCompensatingDestroys(for: constArgs, context)
+  }
+  let newArguments = Array(nonConstArgs.values)
+  rewritePartialApply(partialApply, withSpecialized: specializedCallee, arguments: newArguments, context)
+}
+
+private func getSpecializedCalleeWithDeadParams(of partialApply: PartialApplyInst,
+                                                _ context: FunctionPassContext
+) -> Function? {
+  guard let specialized = partialApply.getCalleeOfForwardingThunkWithDeadCaptures(),
+        specialized.abi == .Swift
+  else {
+    return nil
+  }
+
+  // Specialize the callee if it is generic
+  if partialApply.substitutionMap.hasAnySubstitutableParams {
+    guard specialized.isDefinition,
+          partialApply.referencedFunction!.shouldOptimize, specialized.shouldOptimize
+    else {
+      return nil
+    }
+
+    let genericSpecialized = context.specialize(function: specialized, for: partialApply.substitutionMap,
+                                                convertIndirectToDirect: false, isMandatory: false)
+    return genericSpecialized
+  }
+
+  return specialized
+}
+
+private func specializeClosure(specializedName: String,
+                               partialApply: PartialApplyInst,
+                               constantArguments: [Operand], nonConstantArguments: [Operand],
+                               _ context: FunctionPassContext
+) -> Function {
+  let callee = partialApply.referencedFunction!
+  var newParams = [ParameterInfo]()
+  newParams.append(contentsOf: callee.convention.parameters.dropLast(partialApply.numArguments))
+  newParams.append(contentsOf: nonConstantArguments.map { partialApply.parameter(for: $0)! })
+
+  let isGeneric = newParams.contains { $0.type.hasTypeParameter } ||
+                  callee.convention.results.contains { $0.type.hasTypeParameter() } ||
+                  callee.convention.errorResult?.type.hasTypeParameter() ?? false
+
+  let specializedClosure = context.createSpecializedFunctionDeclaration(from: callee,
+                                                                        withName: specializedName,
+                                                                        withParams: newParams,
+                                                                        preserveGenericSignature: isGeneric)
+
+  context.buildSpecializedFunction(specializedFunction: specializedClosure) { (specializedClosure, specContext) in
+    cloneAndSpecializeFunction(from: callee, toEmpty: specializedClosure,
+                               substitutions: partialApply.substitutionMap,
+                               specContext)
+
+    let entryBlock = specializedClosure.entryBlock
+    for constArgOp in constantArguments {
+      cloneArgument(constArgOp, of: partialApply, to: specializedClosure, specContext)
+    }
+    // Erase the cloned arguments from the entry block.
+    for constArgOp in constantArguments.reversed() {
+      let calleeArgIdx = partialApply.calleeArgumentIndex(of: constArgOp)!
+      entryBlock.eraseArgument(at: calleeArgIdx, specContext)
+    }
+  }
+  context.notifyNewFunction(function: specializedClosure, derivedFrom: callee)
+  return specializedClosure
+}
+
+private func cloneArgument(_ argumentOp: Operand,
+                           of partialApply: PartialApplyInst,
+                           to targetFunction: Function,
+                           _ context: FunctionPassContext
+) {
+  var argCloner = Cloner(cloneBefore: targetFunction.entryBlock.instructions.first!, context)
+  defer { argCloner.deinitialize() }
+
+  let clonedArg = argCloner.cloneRecursively(value: argumentOp.value)
+  let calleeArgIdx = partialApply.calleeArgumentIndex(of: argumentOp)!
+  let calleeArg = targetFunction.arguments[calleeArgIdx]
+  calleeArg.uses.replaceAll(with: clonedArg, context)
+
+  if partialApply.calleeArgumentConventions[calleeArgIdx].isGuaranteed {
+    // If the original argument was passed as guaranteed, i.e. is _not_ destroyed in the closure, we have
+    // to destroy the cloned argument at function exits.
+    Builder.insertCleanupAtFunctionExits(of: targetFunction, context) { builder in
+      builder.emitDestroy(of: clonedArg)
+    }
+  }
+
+}
+
+private func addCompensatingDestroys(for constantArguments: [Operand], _ context: FunctionPassContext) {
+  for argOp in constantArguments {
+    let builder = Builder(before: argOp.instruction, context)
+    builder.emitDestroy(of: argOp.value)
+  }
+}
+
+private func rewritePartialApply(_ partialApply: PartialApplyInst, withSpecialized specialized: Function,
+                                 arguments: [Value], _ context: FunctionPassContext) {
+  let builder = Builder(before: partialApply, context)
+  let fri = builder.createFunctionRef(specialized)
+  let newClosure: Value
+  if arguments.isEmpty {
+    newClosure = builder.createThinToThickFunction(thinFunction: fri, resultType: partialApply.type)
+    context.erase(instructions: partialApply.uses.users(ofType: DeallocStackInst.self))
+  } else {
+    newClosure = builder.createPartialApply(
+      function: fri,
+      substitutionMap: specialized.genericSignature.isEmpty ? SubstitutionMap() : partialApply.substitutionMap,
+      capturedArguments: arguments, calleeConvention: partialApply.calleeConvention,
+      hasUnknownResultIsolation: partialApply.hasUnknownResultIsolation, isOnStack: partialApply.isOnStack)
+  }
+  partialApply.uses.replaceAll(with: newClosure, context)
+
+  // Bypass any mark_dependence on the captures we specialized away.
+  //
+  // TODO: If we start to specialize away key path literals with operands (subscripts etc.), then a
+  // dependence of the new partial_apply on those operands may still exist. However, we should still
+  // leave the key path itself out of the dependency chain, and introduce dependencies on those
+  // operands instead, so that the key path object itself can be made dead.
+  for md in newClosure.uses.users(ofType: MarkDependenceInst.self) {
+    if md.base.uses.getSingleUser(ofType: PartialApplyInst.self) == partialApply {
+      md.replace(with: newClosure, context)
+    }
+  }
+  context.erase(instruction: partialApply)
+}
+
+private extension PartialApplyInst {
+
+  /// Returns the callee if this is a `partial_apply` of a thunk which directly forwards all arguments
+  /// to the callee and has no other side-effects.
+  func getCalleeOfForwardingThunkWithDeadCaptures() -> Function? {
+    guard let thunk = referencedFunction,
+          let thunkEntryBlock = thunk.blocks.first
+    else {
+      return nil
+    }
+    let numDeadArguments = self.arguments.count
+    let numAliveArgs = thunkEntryBlock.arguments.count - numDeadArguments
+    let deadCalleeArgs = thunkEntryBlock.arguments.dropFirst(numAliveArgs)
+
+    // TODO: handle non-trivial dead arguments, i.e. accept destroy instructions of such arguments.
+    guard deadCalleeArgs.allSatisfy({ $0.type.isTrivial(in: thunk )}) else {
+      return nil
+    }
+
+    var callee: Function? = nil
+    var returnValue: Value? = nil
+    var errorValue: Value? = nil
+
+    for inst in thunk.instructions {
+      switch inst {
+      case let apply as ApplyInst:
+        guard callee == nil, let c = apply.getCalleeWithForwardedArguments(numArguments: numAliveArgs) else {
+          return nil
+        }
+        callee = c
+        returnValue = apply
+      case let tryApply as TryApplyInst:
+        guard callee == nil,
+              let c = tryApply.getCalleeWithForwardedArguments(numArguments: numAliveArgs)
+        else {
+          return nil
+        }
+        callee = c
+        returnValue = tryApply.normalBlock.arguments.first
+        errorValue = tryApply.errorBlock.arguments.first
+      case let returnInst as ReturnInst:
+        guard let returnValue, returnInst.returnedValue == returnValue else {
+          return nil
+        }
+      case let throwInst as ThrowInst:
+        guard let errorValue, throwInst.thrownValue == errorValue else {
+          return nil
+        }
+      case is TermInst:
+        return nil
+      default:
+        if inst.mayHaveSideEffects {
+          return nil
+        }
+      }
+    }
+    return callee
+  }
+
+  func classifyArgumentsForConstness() -> (constArguments: [Operand], nonConstArguments: [Operand])? {
+    var constArgs = [Operand]()
+    var nonConstArgs = [Operand]()
+    var hasKeypath = false
+    for argOp in argumentOperands {
+      // In non-OSSA we don't know where to insert the compensating release for a propagated keypath.
+      // Therefore bail if a keypath has multiple uses.
+      switch argOp.value.isConstant(requireSingleUse: !parentFunction.hasOwnership && !isOnStack) {
+      case .constant:
+        constArgs.append(argOp)
+      case .constantWithKeypath:
+        constArgs.append(argOp)
+        hasKeypath = true
+      case .notConstant:
+        nonConstArgs.append(argOp)
+      }
+    }
+
+    // The optimization is beneficial if we can either get rid of all captures, because this
+    // avoids allocating the context.
+    // Or if we can constant propagate at least one keypath. Keypaths are so expensive that constant
+    // propagating a single keypath is already beneficial.
+    if !constArgs.isEmpty,
+       nonConstArgs.isEmpty || hasKeypath
+    {
+      return (constArgs, nonConstArgs)
+    }
+    return nil
+  }
+}
+
+private extension FullApplySite {
+  func getCalleeWithForwardedArguments(numArguments: Int) -> Function? {
+    if let callee = referencedFunction,
+       callee.numArguments == numArguments,
+       zip(parentFunction.entryBlock.arguments, arguments).allSatisfy({ $0.0 == $0.1 })
+    {
+      return callee
+    }
+    return nil
+  }
+}
+
+private enum ConstantKind {
+  case notConstant
+  case constant
+  case constantWithKeypath
+
+  func merge(with other: ConstantKind) -> ConstantKind {
+    switch (self, other) {
+      case (.notConstant, _):      return .notConstant
+      case (_, .notConstant):      return .notConstant
+      case (.constant, .constant): return .constant
+      default:                     return .constantWithKeypath
+    }
+  }
+}
+
+private extension Value {
+  func isConstant(requireSingleUse: Bool) -> ConstantKind {
+    // All instructions handled here must also be handled in
+    // `FunctionSignatureSpecializationMangler::mangleConstantProp`.
+    let result: ConstantKind
+    switch self {
+    case let si as StructInst:
+      result = si.operands.reduce(.constant, {
+        $0.merge(with: $1.value.isConstant(requireSingleUse: requireSingleUse))
+      })
+    case is ThinToThickFunctionInst, is ConvertFunctionInst, is UpcastInst, is OpenExistentialRefInst:
+      result = (self as! UnaryInstruction).operand.value.isConstant(requireSingleUse: requireSingleUse)
+    case is StringLiteralInst, is IntegerLiteralInst, is FloatLiteralInst, is FunctionRefInst, is GlobalAddrInst:
+      result = .constant
+    case let keyPath as KeyPathInst:
+      guard keyPath.operands.isEmpty,
+            keyPath.hasPattern,
+            !keyPath.substitutionMap.hasAnySubstitutableParams
+      else {
+        return .notConstant
+      }
+      result = .constantWithKeypath
+    default:
+      return .notConstant
+    }
+    if requireSingleUse, result == .constantWithKeypath, !uses.ignoreDebugUses.isSingleUse {
+      return .notConstant
+    }
+    return result
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CopyToBorrowOptimization.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CopyToBorrowOptimization.swift
index b9caf36d8b892..3e00c4eea75ab 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CopyToBorrowOptimization.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CopyToBorrowOptimization.swift
@@ -39,7 +39,7 @@ import SIL
 /// ```
 
 /// The optimization can be done if:
-/// * In caseof a `load`: during the (forward-extended) lifetime of the loaded value the
+/// * In case of a `load`: during the (forward-extended) lifetime of the loaded value the
 ///                       memory location is not changed.
 /// * In case of a `copy_value`: the (guaranteed) lifetime of the source operand extends
 ///                       the lifetime of the copied value.
@@ -360,6 +360,13 @@ private extension Value {
   }
 
   var lookThroughForwardingInstructions: Value {
+    if let bfi = definingInstruction as? BorrowedFromInst,
+       !bfi.borrowedPhi.isReborrow,
+       bfi.enclosingValues.count == 1
+    {
+      // Return the single forwarded enclosingValue
+      return bfi.enclosingValues[0]
+    }
     if let fi = definingInstruction as? ForwardingInstruction,
        let forwardedOp = fi.singleForwardedOperand
     {
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeadStoreElimination.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeadStoreElimination.swift
index 26d765f47907f..ef7eb618e10f9 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeadStoreElimination.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeadStoreElimination.swift
@@ -76,7 +76,7 @@ let deadStoreElimination = FunctionPass(name: "dead-store-elimination") {
 
 private func tryEliminate(store: StoreInst, complexityBudget: inout Int, _ context: FunctionPassContext) {
   // Check if the type can be expanded without a significant increase to code
-  // size. This pass splits values into its consitutent parts which effectively
+  // size. This pass splits values into its constituent parts which effectively
   // expands the value into projections which can increase code size.
   if !store.hasValidOwnershipForDeadStoreElimination || !store.source.type.shouldExpand(context) {
     return
@@ -167,8 +167,15 @@ private extension StoreInst {
 
   var hasValidOwnershipForDeadStoreElimination: Bool {
     switch storeOwnership {
-    case .unqualified, .trivial:
+    case .unqualified:
       return true
+    case .trivial:
+      // Storing a trivial enum case in a non-trivial enum must be treated like a non-trivial
+      // init or assign, e.g.
+      //   %1 = enum $Optional<String>, #Optional.none!enumelt
+      //   store %1 to [trivial] %0  // <- cannot delete this store!
+      //   store %2 to [assign] %0
+      return source.type.isTrivial(in: parentFunction)
     case .initialize, .assign:
       // In OSSA, non-trivial values cannot be dead-store eliminated because that could shrink
       // the lifetime of the original stored value (because it's not kept in memory anymore).
@@ -256,7 +263,7 @@ private extension Deallocation {
 
 private extension DeallocStackInst {
   func isStackDeallocation(of base: AccessBase) -> Bool {
-    if case .stack(let allocStack) = base, allocstack == allocStack {
+    if case .stack(let allocStack) = base, operand.value == allocStack {
       return true
     }
     return false
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeinitDevirtualizer.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeinitDevirtualizer.swift
index aa8553adefbc7..3682d78de5025 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeinitDevirtualizer.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeinitDevirtualizer.swift
@@ -27,6 +27,8 @@ let deinitDevirtualizer = FunctionPass(name: "deinit-devirtualizer") {
       _ = devirtualizeDeinits(of: destroyValue, context)
     case let destroyAddr as DestroyAddrInst:
       _ = devirtualizeDeinits(of: destroyAddr, context)
+    case let builtin as BuiltinInst:
+      _ = devirtualizeDeinits(of: builtin, context)
     default:
       break
     }
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DestroyHoisting.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DestroyHoisting.swift
index e240991749f64..42f521711cdbe 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DestroyHoisting.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DestroyHoisting.swift
@@ -83,7 +83,7 @@ let destroyHoisting = FunctionPass(name: "destroy-hoisting") {
 private func optimize(value: Value, _ context: FunctionPassContext) {
   guard value.ownership == .owned,
         // Avoid all the analysis effort if there are no destroys to hoist.
-        !value.uses.filterUsers(ofType: DestroyValueInst.self).isEmpty
+        !value.uses.filterUses(ofType: DestroyValueInst.self).isEmpty
   else {
     return
   }
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DiagnoseInfiniteRecursion.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DiagnoseInfiniteRecursion.swift
index 0e1d88425c583..84683e97bcced 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DiagnoseInfiniteRecursion.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DiagnoseInfiniteRecursion.swift
@@ -289,7 +289,7 @@ private struct Analysis {
     worklist.pushIfNotVisited(function.entryBlock)
     while let block = worklist.pop() {
       if case .recursive(let apply) = block.getKind(for: invariants, context) {
-        context.diagnosticEngine.diagnose(apply.location.sourceLoc, .warn_infinite_recursive_call)
+        context.diagnosticEngine.diagnose(.warn_infinite_recursive_call, at: apply.location)
       } else {
         for succ in block.successors where isInInfiniteRecursionLoop(succ) {
           worklist.pushIfNotVisited(succ)
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/InitializeStaticGlobals.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/InitializeStaticGlobals.swift
index 7dd89bffac9c1..2526ac706327d 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/InitializeStaticGlobals.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/InitializeStaticGlobals.swift
@@ -45,324 +45,587 @@ import SIL
 let initializeStaticGlobalsPass = FunctionPass(name: "initialize-static-globals") {
   (function: Function, context: FunctionPassContext) in
 
-  if context.hadError {
-    // In case of a preceding error, there is no guarantee that the SIL is valid.
-    return
-  }
-
-  if !function.isGlobalInitOnceFunction {
-    return
-  }
-
-  // Sometimes structs are not stored in one piece, but as individual elements.
-  // Merge such individual stores to a single store of the whole struct.
-  mergeStores(in: function, context)
-
-  guard let (allocInst, storeToGlobal, inlineArrays) = getGlobalInitializerInfo(of: function, context) else {
-    return
-  }
-
-  if !allocInst.global.canBeInitializedStatically {
+  guard // In case of a preceding error, there is no guarantee that the SIL is valid.
+        !context.hadError,
+        // Is `function` a global init function?
+        let global = function.initializedGlobal,
+        // Even if the init value is a constant, the initializer can have side effects, e.g.
+        //   let g = { print("hello"); return 27 }()
+        !function.hasSideEffects(besideStoringTo: global),
+        // Try to get a constant global init value.
+        let initValue = GlobalInitValue(of: function, context)
+  else {
     return
   }
 
-  /// Replace inline arrays, which are allocated in stack locations with `vector` instructions.
-  /// Note that `vector` instructions are only allowed in global initializers. Therefore it's important
-  /// that the code in this global initializer is eventually completely removed after copying it to the global.
-  for array in inlineArrays {
-    lowerInlineArray(array: array, context)
-  }
-    
-  var cloner = StaticInitCloner(cloneTo: allocInst.global, context)
-  defer { cloner.deinitialize() }
-
-  _ = cloner.clone(storeToGlobal.source)
+  initValue.materialize(into: global, from: function, context)
 
   // The initial value can contain a `begin_access` if it references another global variable by address, e.g.
   //   var p = Point(x: 10, y: 20)
   //   let o = UnsafePointer(&p)
   //
-  allocInst.global.stripAccessInstructionFromInitializer(context)
+  global.stripAccessInstructionFromInitializer(context)
 
-  context.erase(instruction: allocInst)
-  context.erase(instruction: storeToGlobal)
-  context.removeTriviallyDeadInstructionsIgnoringDebugUses(in: function)
+  function.removeAllInitializationCode(for: global, context)
 }
 
-/// Gets all info about a global initializer function if it can be converted to a statically initialized global.
-private func getGlobalInitializerInfo(
-  of function: Function,
-  _ context: FunctionPassContext
-) -> (allocInst: AllocGlobalInst, storeToGlobal: StoreInst, inlineArrays: [InlineArray])? {
-
-  var arrayInitInstructions = InstructionSet(context)
-  defer { arrayInitInstructions.deinitialize() }
-  
-  var inlineArrays = [InlineArray]()
-  
-  guard let (allocInst, storeToGlobal) = getGlobalInitialization(of: function, context,
-    handleUnknownInstruction: { inst in
-      if let asi = inst as? AllocStackInst {
-        if let array = getInlineArrayInfo(of: asi) {
-          inlineArrays.append(array)
-          arrayInitInstructions.insertAllAddressUses(of: asi)
-          return true
+/// A tree, which represents a constant init value of a global variable.
+private indirect enum GlobalInitValue {
+  case undefined
+
+  // A value which is a SIL "constant", e.g. a literal instruction, a struct/tuple of literals, etc.
+  case constant(Value)
+
+  // A struct, tuple or vector, which is _not_ a SIL "constant".
+  // For example, a struct or vector which is initialized by storing its elements.
+  case aggregate([GlobalInitValue])
+
+  // An enum case without a payload of an address-only enum.
+  case enumCase(caseIndex: Int)
+
+  // An enum case which is not a SIL "constant", e.g. because it's address-only
+  case enumCaseWithPayload(caseIndex: Int, payload: GlobalInitValue)
+
+  init?(of globalInitFunction: Function, _ context: FunctionPassContext) {
+    self = .undefined
+    var global: GlobalVariable? = nil
+
+    // The init values for temporary stack locations. This is needed if e.g. a vector is initialized in a
+    // stack location and the loaded from it and stored in the global.
+    var stackValues = Dictionary<AllocStackInst, GlobalInitValue>()
+
+    for inst in globalInitFunction.instructions {
+      switch inst {
+      case let allocGlobal as AllocGlobalInst:
+        guard global == nil, allocGlobal.global.canBeInitializedStatically else {
+          return nil
         }
-        return false
+        global = allocGlobal.global
+      case let ga as GlobalAddrInst where ga.global == global:
+        // SILGen only creates a single global_addr in the init function. So no need to support multiple ones.
+        guard case .undefined = self,
+              let selfInitVal = GlobalInitValue(of: ga, context)
+        else {
+          return nil
+        }
+        self = selfInitVal
+      case let allocStack as AllocStackInst:
+        guard let stackInitVal = GlobalInitValue(of: allocStack, context) else {
+          return nil
+        }
+        stackValues[allocStack] = stackInitVal
+      default:
+        break
       }
-      // Accept all instructions which are part of inline array initialization, because we'll remove them anyway.
-      return arrayInitInstructions.contains(inst)
-    })
-  else {
-    return nil
+    }
+
+    // At this point some `.constant` elements can be (or contain) loads from stack locations.
+    // Replace those elements with the init value of the corresponding stack location.
+    resolveLoads(from: &stackValues, context)
+
+    if !isValid(context) {
+      return nil
+    }
   }
 
-  return (allocInst, storeToGlobal, inlineArrays)   
-}
+  private init?(of address: Value, _ context: FunctionPassContext) {
+    var builder = InitValueBuilder(originalAddress: address)
+    if builder.walkDownUses(ofAddress: address, path: UnusedWalkingPath()) == .abortWalk {
+      return nil
+    }
+    self = builder.initValue
+  }
 
-/// Represents an inline array which is initialized by a literal.
-private struct InlineArray {
-  let elementType: Type
-  
-  /// In case the `elementType` is a tuple, the element values are flattened,
-  /// i.e. `elements` contains elementcount * tupleelements values.
-  let elements: [Value]
-  
-  /// The final load instruction which loads the initialized array from a temporary stack location.
-  let finalArrayLoad: LoadInst
-  
-  /// The stack location which contains the initialized array.
-  var stackLoocation: AllocStackInst { finalArrayLoad.address as! AllocStackInst }
-}
+  enum InitValue {
+    // The common case
+    case value(Value)
+
+    // For payload-less cases of address-only enums. Such cases are initialized purely with an `inject_enum_addr`,
+    // and we don't have a `Value` which represents the resulting enum(-case).
+    case enumCaseWithoutPayload(InjectEnumAddrInst)
 
-/// Replaces an initialized inline array (which is allocated in a temporary stack location) with a
-/// `vector` instruction.
-/// The stack location of the array is removed.
-private func lowerInlineArray(array: InlineArray, _ context: FunctionPassContext) {
-  let vector: VectorInst
-  let builder = Builder(after: array.finalArrayLoad, context)
-  if array.elementType.isTuple {
-    let numTupleElements = array.elementType.tupleElements.count
-    assert(array.elements.count % numTupleElements == 0)
-    var tuples: [TupleInst] = []
-    for tupleIdx in 0..<(array.elements.count / numTupleElements) {
-      let range = (tupleIdx * numTupleElements) ..< ((tupleIdx + 1) * numTupleElements) 
-      let tuple = builder.createTuple(type: array.elementType, elements: Array(array.elements[range]))
-      tuples.append(tuple)
+    var parentFunction: Function {
+      switch self {
+        case .value(let value):  return value.parentFunction
+        case .enumCaseWithoutPayload(let iea): return iea.parentFunction
+      }
     }
-    vector = builder.createVector(type: array.elementType, arguments: tuples)
-  } else {
-    vector = builder.createVector(type: array.elementType, arguments: array.elements)      
   }
-  array.finalArrayLoad.uses.replaceAll(with: vector, context)
-  context.erase(instructionIncludingAllUsers: array.stackLoocation)
-}
 
-/// An alloc_stack could be a temporary object which holds an initialized inline-array literal.
-/// It looks like:
-///
-///     %1 = alloc_stack $InlineArray<Count, ElementType>
-///     %2 = unchecked_addr_cast %1 to $*ElementType      // the elementStorage
-///     store %firstElement to [trivial] %2
-///     %4 = integer_literal $Builtin.Word, 1
-///     %5 = index_addr %2, %4
-///     store %secondElement to [trivial] %5
-///     ...
-///     %10 = load [trivial] %1                   // the final arrayLoad
-///     dealloc_stack %1
-///
-/// Returns nil if `allocStack` is not a properly initialized inline array.
-///
-private func getInlineArrayInfo(of allocStack: AllocStackInst) -> InlineArray? {
-  var arrayLoad: LoadInst? = nil
-  var elementStorage: UncheckedAddrCastInst? = nil
-
-  for use in allocStack.uses {
-    switch use.instruction {
-    case let load as LoadInst:
-      if arrayLoad != nil {
-        return nil
+  // Sets an element in the constant tree.
+  // Returns true if this was successful. One reason for being not successful is if a certain
+  // element is set twice, i.e. does not have a single defined value.
+  mutating func setElement(to value: InitValue, at path: SmallProjectionPath, type: Type) -> Bool {
+    let (kind, index, subPath) = path.pop()
+    switch kind {
+    case .root:
+      guard case .undefined = self else {
+        // The element was set twice.
+        return false
       }
-      // It's guaranteed that the array load is located after all element stores.
-      // Otherwise it would load uninitialized memory.
-      arrayLoad = load
-    case is DeallocStackInst:
-      break
-    case let addrCastToElement as UncheckedAddrCastInst:
-      if elementStorage != nil {
-        return nil
+      switch value {
+      case .value(let value):
+        self = .constant(value)
+      case .enumCaseWithoutPayload:
+        fatalError("should have been handled in the .enumCase of the SmallProjectionPath below")
       }
-      elementStorage = addrCastToElement
+      return true
+
+    case .enumCase:
+      return setEnumCase(to: value, at: subPath, index: index, type: type)
+
+    case .structField:
+      guard let structFields = type.getNominalFields(in: value.parentFunction) else {
+        return false
+      }
+      return setField(to: value, at: subPath, index: index, type: structFields[index], numFields: structFields.count)
+
+    case .tupleField:
+      let tupleElements = type.tupleElements
+      return setField(to: value, at: subPath, index: index, type: tupleElements[index], numFields: tupleElements.count)
+
+    case .vectorBase:
+      let elementType = type.builtinFixedArrayElementType(in: value.parentFunction)
+      guard let vectorSize = type.builtinFixedArraySizeType.valueOfInteger else {
+        return false
+      }
+      let (indexKind, vectorIndex, vectorSubPath) = subPath.pop()
+      switch indexKind {
+      case .indexedElement:
+        return setField(to: value, at: vectorSubPath, index: vectorIndex, type: elementType, numFields: vectorSize)
+      case .anyIndexedElement:
+        // A non-constant index means: all elements are initialized with the same value.
+        // (that's what we checked in `storesToAllVectorElements`)
+        for i in 0..<vectorSize {
+          if !setField(to: value, at: vectorSubPath, index: i, type: elementType, numFields: vectorSize) {
+            return false
+          }
+        }
+        return true
+      default:
+        // A missing index in the path means: the first element
+        return setField(to: value, at: subPath, index: 0, type: elementType, numFields: vectorSize)
+      }
+
     default:
-      return nil
+      return false
     }
   }
-  guard let arrayLoad, let elementStorage else {
-    return nil
-  } 
-  
-  var stores = Array<StoreInst?>()
-  if !findArrayElementStores(toElementAddress: elementStorage, elementIndex: 0, stores: &stores) {
-    return nil
-  }
-  if stores.isEmpty {
-    // We cannot create an empty `vector` instruction, therefore we don't support empty inline arrays.
-    return nil
-  }
-  // Usually there must be a store for each element. Otherwise the `arrayLoad` would load uninitialized memory.
-  // We still check this to not crash in some weird corner cases, like the element type is an empty tuple.
-  if stores.contains(nil) {
-    return nil
+
+  private mutating func setField(
+    to value: InitValue, at path: SmallProjectionPath,
+    index: Int, type: Type, numFields: Int
+  ) -> Bool {
+    if case .undefined = self {
+      // Initialize the aggregate array if not done, yet.
+      self = .aggregate(Array(repeating: GlobalInitValue.undefined, count: numFields))
+    }
+    if case .aggregate(let fields) = self {
+      var newFields = fields
+      self = .undefined // avoid copy-on-write
+      if !newFields[index].setElement(to: value, at: path, type: type) {
+        return false
+      }
+      self = .aggregate(newFields)
+      return true
+    }
+    return false
   }
 
-  return InlineArray(elementType: elementStorage.type.objectType,
-                     elements: stores.map { $0!.source },
-                     finalArrayLoad: arrayLoad)
-}
+  private mutating func setEnumCase(to value: InitValue, at path: SmallProjectionPath, index: Int, type: Type) -> Bool {
+    if path.isEmpty, case .enumCaseWithoutPayload(let iea) = value {
 
-/// Recursively traverses all uses of `elementAddr` and finds all stores to an inline array storage.
-/// The element store instructions are put into `stores` - one store for each element.
-/// In case the element type is a tuple, the tuples are flattened. See `InlineArray.elements`.  
-private func findArrayElementStores(
-  toElementAddress elementAddr: Value,
-  elementIndex: Int,
-  stores: inout [StoreInst?]
-) -> Bool {
-  for use in elementAddr.uses {
-    switch use.instruction {
-    case let indexAddr as IndexAddrInst:
-      guard let indexLiteral = indexAddr.index as? IntegerLiteralInst,
-            let tailIdx = indexLiteral.value else
-      {
+      guard case .undefined = self else {
+        // The enum was set twice.
         return false
       }
-      if !findArrayElementStores(toElementAddress: indexAddr, elementIndex: elementIndex + tailIdx, stores: &stores) {
+      assert(index == iea.caseIndex)
+      self = .enumCase(caseIndex: index)
+    } else {
+      guard let payloadType = type.getEnumCases(in: value.parentFunction)!.getPayloadType(ofCaseIndex: index) else {
         return false
       }
-    case let tea as TupleElementAddrInst:
-      // The array elements are tuples. There is a separate store for each tuple element.
-      let numTupleElements = tea.tuple.type.tupleElements.count
-      let tupleIdx = tea.fieldIndex
-      if !findArrayElementStores(toElementAddress: tea,
-                                 elementIndex: elementIndex * numTupleElements + tupleIdx,
-                                 stores: &stores) {
+      switch self {
+      case .undefined:
+        // It's the first time we set the payload or a sub-field of it.
+        var payload = GlobalInitValue.undefined
+        if !payload.setElement(to: value, at: path, type: payloadType) {
+          return false
+        }
+        self = .enumCaseWithPayload(caseIndex: index, payload: payload)
+      case .enumCaseWithPayload(let existingIndex, var payload) where index == existingIndex:
+        // Some sub-field of the enum-payload was already set.
+        self = .undefined // avoid copy-on-write
+        if !payload.setElement(to: value, at: path, type: payloadType) {
+          return false
+        }
+        self = .enumCaseWithPayload(caseIndex: index, payload: payload)
+      default:
         return false
       }
-    case let store as StoreInst:
-      if store.source.type.isTuple {
-        // This kind of SIL is never generated because tuples are stored with separated stores to tuple_element_addr.
-        // Just to be on the safe side..
-        return false
+    }
+    return true
+  }
+
+  /// Creates SIL for this global init value in the initializer of the `global`.
+  func materialize(into global: GlobalVariable, from function: Function, _ context: FunctionPassContext) {
+    var cloner = Cloner(cloneToGlobal: global, context)
+    defer { cloner.deinitialize() }
+    let builder = Builder(staticInitializerOf: global, context)
+
+    _ = materializeRecursively(type: global.type, &cloner, builder, function)
+  }
+
+  private func materializeRecursively(
+    type: Type,
+    _ cloner: inout Cloner<FunctionPassContext>,
+    _ builder: Builder,
+    _ function: Function
+  ) -> Value {
+    switch self {
+    case .undefined:
+      fatalError("cannot materialize undefined init value")
+
+    case .constant(let value):
+      return cloner.cloneRecursively(globalInitValue: value)
+
+    case .aggregate(let fields):
+      if type.isStruct {
+        let fieldTypes = type.getNominalFields(in: function)!
+        let fieldValues = zip(fields, fieldTypes).map {
+          $0.0.materializeRecursively(type: $0.1, &cloner, builder, function)
+        }
+        return builder.createStruct(type: type, elements: fieldValues)
       }
-      if elementIndex >= stores.count {
-        stores += Array(repeating: nil, count: elementIndex - stores.count + 1)
+      if type.isTuple {
+        let elementValues = zip(fields, type.tupleElements).map {
+          $0.0.materializeRecursively(type: $0.1, &cloner, builder, function)
+        }
+        return builder.createTuple(type: type, elements: elementValues)
       }
-      if stores[elementIndex] != nil {
-        // An element is stored twice.
-        return false
+      assert(type.isBuiltinFixedArray)
+      let elementType = type.builtinFixedArrayElementType(in: function)
+      let elementValues = fields.map {
+        $0.materializeRecursively(type: elementType, &cloner, builder, function)
       }
-      stores[elementIndex] = store
-    default:
+      return builder.createVector(type: type, arguments: elementValues)
+
+    case .enumCase(let caseIndex):
+      return builder.createEnum(caseIndex: caseIndex, payload: nil, enumType: type)
+
+    case .enumCaseWithPayload(let caseIndex, let payload):
+      let payloadType = type.getEnumCases(in: function)!.getPayloadType(ofCaseIndex: caseIndex)!
+      let payloadValue = payload.materializeRecursively(type: payloadType, &cloner, builder, function)
+      return builder.createEnum(caseIndex: caseIndex, payload: payloadValue, enumType: type)
+    }
+  }
+
+  // Replace `.constant` elements, which are (or contain) loads, init value of the corresponding stack location.
+  // Some  from stack locations.
+  mutating func resolveLoads(
+    from stackValues: inout Dictionary<AllocStackInst, GlobalInitValue>,
+    _ context: FunctionPassContext
+  ) {
+    var resolvedAllocStacks = InstructionSet(context)
+    defer { resolvedAllocStacks.deinitialize() }
+    resolveLoadsRecursively(from: &stackValues, &resolvedAllocStacks, context)
+  }
+
+  private mutating func resolveLoadsRecursively(
+    from stackValues: inout Dictionary<AllocStackInst, GlobalInitValue>,
+    _ resolvedAllocStacks: inout InstructionSet,
+    _ context: FunctionPassContext
+  ) {
+    switch self {
+    case .undefined, .enumCase:
+      break
+    case .constant(let value):
+      if value.containsLoad(context) {
+        switch value {
+        case is StructInst, is TupleInst:
+          self = .aggregate((value as! Instruction).operands.lazy.map { .constant($0.value) })
+          resolveLoadsRecursively(from: &stackValues, &resolvedAllocStacks, context)
+        case let ei as EnumInst:
+          self = .enumCaseWithPayload(caseIndex: ei.caseIndex, payload: .constant(ei.payload!))
+          resolveLoadsRecursively(from: &stackValues, &resolvedAllocStacks, context)
+        case let li as LoadInst:
+          guard let allocStack = li.address as? AllocStackInst,
+                var stackInit = stackValues[allocStack]
+          else {
+            self = .undefined
+            return
+          }
+          if resolvedAllocStacks.insert(allocStack) {
+            stackInit.resolveLoadsRecursively(from: &stackValues, &resolvedAllocStacks, context)
+            stackValues[allocStack] = stackInit
+          }
+          self = stackInit
+        default:
+          break
+        }
+      }
+    case .aggregate(let fields):
+      var newFields = fields
+      self = .undefined // avoid copy-on-write
+      for i in 0..<fields.count {
+        newFields[i].resolveLoadsRecursively(from: &stackValues, &resolvedAllocStacks, context)
+      }
+      self = .aggregate(newFields)
+    case .enumCaseWithPayload(let caseIndex, var payload):
+      payload.resolveLoadsRecursively(from: &stackValues, &resolvedAllocStacks, context)
+      self = .enumCaseWithPayload(caseIndex: caseIndex, payload: payload)
+    }
+  }
+
+  func isValid(_ context: FunctionPassContext) -> Bool {
+    switch self {
+    case .undefined:
       return false
+    case .constant(let value):
+      return value.isValidGlobalInitValue(context)
+    case .aggregate(let fields):
+      return fields.allSatisfy { $0.isValid(context) }
+    case .enumCase:
+      return true
+    case .enumCaseWithPayload(_, let payload):
+      return payload.isValid(context)
     }
   }
-  return true
 }
 
-/// Merges stores to individual struct fields to a single store of the whole struct.
-///
-///   store %element1 to %element1Addr
-///   store %element2 to %element2Addr
-/// ->
-///   %s = struct $S (%element1, %element2)
-///   store %s to @structAddr
-private func mergeStores(in function: Function, _ context: FunctionPassContext) {
-  for inst in function.instructions {
-    if let store = inst as? StoreInst {
-      if let (elementStores, lastStore) = getSequenceOfElementStores(firstStore: store) {
-        merge(elementStores: elementStores, lastStore: lastStore, context)
+private extension Value {
+  /// Returns true if this value is a `load` or a struct/tuple/enum with a `load` operand.
+  func containsLoad(_ context: FunctionPassContext) -> Bool {
+    var worklist = ValueWorklist(context)
+    defer { worklist.deinitialize() }
+    worklist.pushIfNotVisited(self)
+    while let v = worklist.pop() {
+      switch v {
+      case is LoadInst:
+        return true
+      case is StructInst, is TupleInst:
+        worklist.pushIfNotVisited(contentsOf: (v as! Instruction).operands.values)
+      case let ei as EnumInst:
+        if let payload = ei.payload {
+          worklist.pushIfNotVisited(payload)
+        }
+      default:
+        break
       }
     }
+    return false
   }
 }
 
-/// Returns a sequence of individual stores to elements of a struct.
-///
-///   %addr1 = struct_element_addr %structAddr, #field1
-///   store %element1 to %addr1
-///   // ...
-///   %addr_n = struct_element_addr %structAddr, #field_n
-///   store %element_n to %addr_n
-///
-private func getSequenceOfElementStores(firstStore: StoreInst) -> ([StoreInst], lastStore: StoreInst)? {
-  guard let elementAddr = firstStore.destination as? StructElementAddrInst else {
-    return nil
-  }
-  let structAddr = elementAddr.struct
-  let structType = structAddr.type
-  if structType.isMoveOnly {
-    return nil
-  }
-  if (structType.nominal as! StructDecl).hasUnreferenceableStorage {
-    return nil
-  }
-  guard let fields = structType.getNominalFields(in: firstStore.parentFunction) else {
-    return nil
-  }
-  let numElements = fields.count
-  var elementStores = Array<StoreInst?>(repeating: nil, count: numElements)
-  var numStoresFound = 0
+private struct InitValueBuilder: AddressDefUseWalker {
+  let originalAddress: Value
+  var initValue = GlobalInitValue.undefined
 
-  for inst in InstructionList(first: firstStore) {
-    switch inst {
+  mutating func leafUse(address: Operand, path: UnusedWalkingPath) -> WalkResult {
+    switch address.instruction {
     case let store as StoreInst:
-      guard store.storeOwnership == .trivial,
-            let sea = store.destination as? StructElementAddrInst,
-            sea.struct == structAddr,
-            // Multiple stores to the same element?
-            elementStores[sea.fieldIndex] == nil else {
-        return nil
+      let accessPath = store.destination.lookThroughRawLayoutAddress.constantAccessPath
+      switch accessPath.base {
+      case .global, .stack:
+        if !initValue.setElement(to: .value(store.source), at: accessPath.projectionPath, type: originalAddress.type) {
+          return .abortWalk
+        }
+        return .continueWalk
+      case .index(let indexAddr):
+        // If we have a non-constant index in the access path, check if this is from a loop which
+        // initializes all elements.
+        guard store.storesToAllVectorElements(using: indexAddr) else {
+          return .abortWalk
+        }
+        let nonConstAccessPath = store.destination.accessPath
+        guard indexAddr.base.constantAccessPath.base == nonConstAccessPath.base else {
+          return .abortWalk
+        }
+        // The `nonConstAccessPath` now contains a single `.anyIndexedElement`.
+        if !initValue.setElement(to: .value(store.source), at: nonConstAccessPath.projectionPath, type: originalAddress.type) {
+          return .abortWalk
+        }
+        return .continueWalk
+      default:
+        fatalError("could not compute access path")
+      }
+    case let injectEnum as InjectEnumAddrInst:
+      if injectEnum.element.hasAssociatedValues {
+        if !injectEnum.operand.value.type.isLoadable(in: injectEnum.parentFunction) {
+          // TODO: we don't support non-loadable enum cases with payload yet, because IRGen support is missing.
+          //       e.g. `var global: Atomic<Int>? = Atomic<Int>(0)`
+          // FixedTypeInfo (= used for non-loadable types) is missing the ability to pack a payload into an enum.
+          return .abortWalk
+        }
+        return .continueWalk
+      }
+      let accessPath = injectEnum.enum.getAccessPath(fromInitialPath: SmallProjectionPath(.enumCase,
+                                                                                          index: injectEnum.caseIndex))
+      switch accessPath.base {
+      case .global, .stack:
+        if !initValue.setElement(to: .enumCaseWithoutPayload(injectEnum), at: accessPath.projectionPath, type: originalAddress.type) {
+          return .abortWalk
+        }
+        return .continueWalk
+      default:
+        return .abortWalk
       }
 
-      elementStores[sea.fieldIndex] = store
-      numStoresFound += 1
-      if numStoresFound == numElements {
-        // If we saw  `numElements` distinct stores, it implies that all elements in `elementStores` are not nil.
-        return (elementStores.map { $0! }, lastStore: store)
+    case is LoadInst, is DeallocStackInst:
+      return .continueWalk
+    case let bi as BuiltinInst:
+      switch bi.id {
+      case .PrepareInitialization:
+        return .continueWalk
+      case .AddressOfRawLayout:
+        if let addr2Ptr = bi.uses.getSingleUser(ofType: PointerToAddressInst.self) {
+          return walkDownUses(ofAddress: addr2Ptr, path: path)
+        }
+        return .abortWalk
+      default:
+        return .abortWalk
       }
     default:
-      if inst.mayReadOrWriteMemory {
-        return nil
-      }
+      return .abortWalk
     }
   }
-  return nil
 }
 
-private func merge(elementStores: [StoreInst], lastStore: StoreInst, _ context: FunctionPassContext) {
-  let builder = Builder(after: lastStore, context)
+private extension StoreInst {
+  func storesToAllVectorElements(using indexAddr: IndexAddrInst) -> Bool {
+    if let vectorBase = indexAddr.base as? VectorBaseAddrInst,
+       let headerBr = vectorBase.parentBlock.terminator as? BranchInst,
+       headerBr.targetBlock == parentBlock,
+       let vectorSize = vectorBase.vector.type.builtinFixedArraySizeType.valueOfInteger,
+       let (start, loopCount, increment) = getLoopInductionInfo(of: indexAddr.index.lookThroughIndexScalarCast),
+       start == 0, loopCount == vectorSize, increment == 1
+    {
+      return true
+    }
+    return false
+  }
+}
 
-  let structAddr = (lastStore.destination as! StructElementAddrInst).struct
-  let str = builder.createStruct(type: structAddr.type.objectType, elements: elementStores.map { $0.source })
-  builder.createStore(source: str, destination: structAddr, ownership: lastStore.storeOwnership)
+/// Matches the pattern:
+/// ```
+///   %startValue = integer_literal <start>
+///   %incrementValue = integer_literal <increment>
+///   %loopEndValue = integer_literal <loopCount>
+///   br loopBlock(%startValue)
+/// loopBlock(%inductionVar):
+///   %add = builtin "sadd_with_overflow"(%inductionVar, %incrementValue, ...)
+///   %incrementedInductionVar = tuple_extract %add, 0
+///   %loopBreakCondition = builtin "cmp_eq"(%incrementedInductionVar, %loopEndValue)
+///   cond_br %loopBreakCondition, exitBlock, backEdgeBlock
+/// backEdgeBlock:
+///   br loopBlock(%incrementedInductionVar)
+/// exitBlock:
+/// ```
+private func getLoopInductionInfo(of inductionVar: Value) -> (start: Int, loopCount: Int, increment: Int)? {
+  let loopBlock = inductionVar.parentBlock
+  if let inductionVarArg = inductionVar as? Argument, inductionVarArg.parentBlock == loopBlock,
+     let inductionVarPhi = Phi(inductionVarArg),
+     let condBr = loopBlock.terminator as? CondBranchInst,
+     let loopBreakCondition = condBr.condition as? BuiltinInst, loopBreakCondition.id == .ICMP_EQ,
+     let incrementedInductionVar = loopBreakCondition.arguments[0] as? TupleExtractInst,
+     incrementedInductionVar.fieldIndex == 0,
+     let add = incrementedInductionVar.tuple as? BuiltinInst, add.id == .SAddOver,
+     add.arguments[0] == inductionVarArg,
+     let incrementValue = add.arguments[1] as? IntegerLiteralInst,
+     let increment = incrementValue.value,
+     let loopEndValue = loopBreakCondition.arguments[1] as? IntegerLiteralInst,
+     let loopCount = loopEndValue.value,
+     let backEdgeBranch = condBr.falseBlock.terminator as? BranchInst,
+     backEdgeBranch.targetBlock == loopBlock,
+     inductionVarPhi.incomingOperand(inPredecessor: backEdgeBranch.parentBlock).value == incrementedInductionVar,
+     let startValue = inductionVarPhi.incomingValue(notInBlock: backEdgeBranch.parentBlock) as? IntegerLiteralInst,
+     let start = startValue.value
+  {
+    return (start, loopCount, increment)
+  }
+  return nil
+}
 
-  for store in elementStores {
-    let destAddr = store.destination as! StructElementAddrInst
-    context.erase(instruction: store)
-    if destAddr.uses.isEmpty {
-      context.erase(instruction: destAddr)
+private extension Phi {
+  func incomingValue(notInBlock: BasicBlock) -> Value? {
+    if let block = predecessors.lazy.filter({ $0 != notInBlock }).singleElement {
+      return incomingOperand(inPredecessor: block).value
     }
+    return nil
   }
 }
 
-private extension InstructionSet {
-  mutating func insertAllAddressUses(of value: Value) {
-    for use in value.uses {
-      if insert(use.instruction) {
-        for result in use.instruction.results where result.type.isAddress {
-          insertAllAddressUses(of: result)
-        }
+private extension Function {
+  func hasSideEffects(besideStoringTo global: GlobalVariable) -> Bool {
+    return instructions.contains { inst in
+      switch inst {
+      case is DeallocStackInst, is DebugStepInst, is DebugValueInst, is BeginAccessInst, is EndAccessInst:
+        return false
+      case let alloc as AllocGlobalInst where alloc.global == global:
+        return false
+      case let store as StoreInst:
+        return !store.destination.lookThroughRawLayoutAddress.isAddressOfStack(orGlobal: global)
+      case let injectEnum as InjectEnumAddrInst:
+        return !injectEnum.enum.isAddressOfStack(orGlobal: global)
+      case let bi as BuiltinInst where bi.id == .PrepareInitialization:
+        return false
+      default:
+        return inst.hasUnspecifiedSideEffects
       }
     }
   }
+
+  func removeAllInitializationCode(for global: GlobalVariable, _ context: FunctionPassContext) {
+    for inst in instructions {
+      switch inst {
+      case let allocGlobal as AllocGlobalInst where allocGlobal.global == global:
+        context.erase(instruction: allocGlobal)
+      case let globalAddr as GlobalAddrInst where globalAddr.global == global:
+        context.erase(instructionIncludingAllUsers: globalAddr)
+      default:
+        break
+      }
+    }
+    context.removeTriviallyDeadInstructionsIgnoringDebugUses(in: self)
+  }
+}
+
+private extension Value {
+  func isAddressOfStack(orGlobal global: GlobalVariable) -> Bool {
+    switch accessBase {
+    case .global(let g) where g == global:
+      return true
+    case .stack:
+      return true
+    default:
+      return false
+    }
+  }
+
+  /// Looks through a `@_rawLayout` projection, which "type casts" a raw-layout struct to it's content, which
+  /// must match the like-type of the raw-layout, e.g.
+  /// ```
+  /// @_rawLayout(like: T)
+  /// struct S {}
+  ///
+  ///   %2 = builtin "addressOfRawLayout"<S>(%1 : $*S) : $Builtin.RawPointer
+  ///   %3 = pointer_to_address %2 to $*T
+  /// ```
+  var lookThroughRawLayoutAddress: Value {
+    if let ptr2Addr = self as? PointerToAddressInst,
+       let builtin = ptr2Addr.pointer as? BuiltinInst, builtin.id == .AddressOfRawLayout,
+       let likeType = builtin.arguments[0].type.rawLayoutSubstitutedLikeType,
+       builtin.arguments[0].type.rawLayoutSubstitutedCountType == nil,
+       likeType.canonical == type.canonicalType
+    {
+      return builtin.arguments[0]
+    }
+    return self
+  }
+}
+
+private extension EnumCases {
+  func getPayloadType(ofCaseIndex caseIndex: Int) -> Type? {
+    return first(where: { $0.index == caseIndex })!.payload
+  }
 }
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LetPropertyLowering.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LetPropertyLowering.swift
index 2f1e5d3cec5a5..ad456de533ef8 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LetPropertyLowering.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LetPropertyLowering.swift
@@ -122,6 +122,8 @@ private func insertEndInitInstructions(
       use.set(to: ssaUpdater.getValue(atEndOf: use.instruction.parentBlock), context)
     }
   }
+  // This peephole optimization is required to avoid ownership errors.
+  replacePhisWithIncomingValues(phis: ssaUpdater.insertedPhis, context)
 }
 
 private func constructLetInitRegion(
@@ -136,7 +138,7 @@ private func constructLetInitRegion(
   // root-class initializer).
   initRegion.insert(markUninitialized)
 
-  var borrows = Stack<BorrowIntroducingInstruction>(context)
+  var borrows = Stack<BeginBorrowInstruction>(context)
   defer { borrows.deinitialize() }
 
   for inst in markUninitialized.parentFunction.instructions {
@@ -153,7 +155,7 @@ private func constructLetInitRegion(
 
     case let copy as CopyAddrInst
          where copy.destination.isLetFieldAddress(of: markUninitialized):
-      assert(copy.isInitializationOfDest)
+      assert(copy.isInitializationOfDestination)
       initRegion.insert(inst)
 
     case let beginAccess as BeginAccessInst
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceDiagnostics.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceDiagnostics.swift
index 679a3ae276c59..b7bd49bb7923a 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceDiagnostics.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceDiagnostics.swift
@@ -53,7 +53,7 @@ let lifetimeDependenceDiagnosticsPass = FunctionPass(
     }
   }
   for instruction in function.instructions {
-    if let markDep = instruction as? MarkDependenceInst, markDep.isUnresolved {
+    if let markDep = instruction as? MarkDependenceInstruction, markDep.isUnresolved {
       if let lifetimeDep = LifetimeDependence(markDep, context) {
         if analyze(dependence: lifetimeDep, context) {
           // Note: This promotes the mark_dependence flag but does not invalidate analyses; preserving analyses is good,
@@ -66,18 +66,22 @@ let lifetimeDependenceDiagnosticsPass = FunctionPass(
       // For now, if the mark_dependence wasn't recognized as a lifetime dependency, or if the dependencies uses are not
       // in scope, conservatively settle it as escaping. For example, it is not uncommon for the pointer value returned
       // by `unsafeAddress` to outlive its `self` argument. This will not be diagnosed as an error, but the
-      // mark_dependence will hanceforth be treated as an unknown use by the optimizer.  In the future, we should not
+      // mark_dependence will henceforth be treated as an unknown use by the optimizer.  In the future, we should not
       // need to set this flag during diagnostics because, for escapable types, mark_dependence [unresolved] will all be
       // settled during an early LifetimeNormalization pass.
-      markDep.settleToEscaping()
+      markDep.settleToEscaping(context)
       continue
     }
-    if let apply = instruction as? FullApplySite {
-      // Handle ~Escapable results that do not have a lifetime dependence. This includes implicit initializers and
-      // @_unsafeNonescapableResult.
+    if let apply = instruction as? FullApplySite, !apply.hasResultDependence {
+      // Handle ~Escapable results that do not have a lifetime dependence. This includes implicit initializers, calls to
+      // closures, and @_unsafeNonescapableResult.
       apply.resultOrYields.forEach {
-        if let lifetimeDep = LifetimeDependence(unsafeApplyResult: $0,
-                                                context) {
+        if let lifetimeDep = LifetimeDependence(unsafeApplyResult: $0, apply: apply, context) {
+          _ = analyze(dependence: lifetimeDep, context)
+        }
+      }
+      apply.indirectResultOperands.forEach {
+        if let lifetimeDep = LifetimeDependence(unsafeApplyResult: $0.value, apply: apply, context) {
           _ = analyze(dependence: lifetimeDep, context)
         }
       }
@@ -106,6 +110,20 @@ private func analyze(dependence: LifetimeDependence, _ context: FunctionPassCont
     }
   }
 
+  // Check for immortal dependence.
+  switch dependence.scope {
+  case .global:
+    log("Immortal global dependence.")
+    return true
+  case let .unknown(value):
+    if value.type.isVoid {
+      log("Immortal void dependence.")
+      return true
+    }
+  default:
+    break
+  }
+
   // Compute this dependence scope.
   var range = dependence.computeRange(context)
   defer { range?.deinitialize() }
@@ -135,13 +153,13 @@ private struct DiagnoseDependence {
 
   func diagnose(_ position: SourceLoc?, _ id: DiagID,
                 _ args: DiagnosticArgument...) {
-    context.diagnosticEngine.diagnose(position, id, args)
+    context.diagnosticEngine.diagnose(id, arguments: args, at: position)
   }
 
   /// Check that this use is inside the dependence scope.
   func checkInScope(operand: Operand) -> WalkResult {
     if let range, !range.inclusiveRangeContains(operand.instruction) {
-      log("  out-of-range: \(operand.instruction)")
+      log("  out-of-range error: \(operand.instruction)")
       reportError(operand: operand, diagID: .lifetime_outside_scope_use)
       return .abortWalk
     }
@@ -150,7 +168,7 @@ private struct DiagnoseDependence {
   }
 
   func reportEscaping(operand: Operand) {
-    log("  escaping: \(operand.instruction)")
+    log("  escaping error: \(operand.instruction)")
     reportError(operand: operand, diagID: .lifetime_outside_scope_escape)
   }
 
@@ -195,19 +213,46 @@ private struct DiagnoseDependence {
     if function.hasUnsafeNonEscapableResult {
       return .continueWalk
     }
-    // If the dependence scope is global, then it has immortal lifetime.
-    if case .global = dependence.scope {
+    // Check for immortal lifetime.
+    //
+    // FIXME: remove this immortal check. It should be redundant with the earlier check that bypasses dependence
+    // diagnostics.
+    switch dependence.scope {
+    case .global:
       return .continueWalk
+    case let .unknown(value):
+      if value.type.isVoid {
+        return .continueWalk
+      }
+    default:
+      break
     }
     // Check that the parameter dependence for this result is the same
     // as the current dependence scope.
     if let arg = dependence.scope.parentValue as? FunctionArgument,
-       function.argumentConventions[resultDependsOn: arg.index] != nil {
-      // The returned value depends on a lifetime that is inherited or
-      // borrowed in the caller. The lifetime of the argument value
-      // itself is irrelevant here.
-      log("  has dependent function result")
-      return .continueWalk
+       let argDep = function.argumentConventions[resultDependsOn: arg.index] {
+      switch argDep {
+      case .inherit:
+        if dependence.markDepInst != nil {
+          // A mark_dependence represents a "borrow" scope. A local borrow scope cannot inherit the caller's dependence
+          // because the borrow scope depends on the argument value itself, while the caller allows the result to depend
+          // on a value that the argument was copied from.
+          break
+        }
+        fallthrough
+      case .scope:
+        // The returned value depends on a lifetime that is inherited or
+        // borrowed in the caller. The lifetime of the argument value
+        // itself is irrelevant here.
+        log("  has dependent function result")
+        return .continueWalk
+      }
+      // Briefly (April 2025), RawSpan._extracting, Span._extracting, and UTF8Span.span returned a borrowed value that
+      // depended on a copied argument. Continue to support those interfaces. The implementations were correct but
+      // needed an explicit _overrideLifetime.
+      if let sourceFileKind = dependence.function.sourceFileKind, sourceFileKind == .interface {
+        return .continueWalk
+      }
     }
     return .abortWalk
   }
@@ -220,38 +265,57 @@ private struct DiagnoseDependence {
     onError()
 
     // Identify the escaping variable.
-    let escapingVar = LifetimeVariable(dependent: operand.value, context)
-    let varName = escapingVar.name
-    if let varName {
-      diagnose(escapingVar.sourceLoc, .lifetime_variable_outside_scope,
-               varName)
+    let escapingVar = LifetimeVariable(usedBy: operand, context)
+    if let varDecl = escapingVar.varDecl {
+      // Use the variable location, not the access location.
+      // Variable names like $return_value and $implicit_value don't have source locations.
+      let sourceLoc = varDecl.nameLoc ?? escapingVar.sourceLoc
+      diagnose(sourceLoc, .lifetime_variable_outside_scope, escapingVar.name ?? "")
+    } else if let sourceLoc = escapingVar.sourceLoc {
+      diagnose(sourceLoc, .lifetime_value_outside_scope)
     } else {
-      diagnose(escapingVar.sourceLoc, .lifetime_value_outside_scope)
+      // Always raise an error even if we can't find a source location.
+      let sourceLoc = function.location.sourceLoc
+      if let accessorKind =  escapingVar.accessorKind {
+        diagnose(sourceLoc, .lifetime_value_outside_accessor, accessorKind)
+      } else {
+        // Thunks do not have a source location, but we try to use the function location anyway.
+        let thunkSelect = dependence.function.thunkKind == .noThunk ? 0 : 1
+        diagnose(sourceLoc, .lifetime_value_outside_thunk, thunkSelect, function.name)
+      }
     }
+    diagnoseImplicitFunction()
     reportScope()
     // Identify the use point.
-    let userSourceLoc = operand.instruction.location.sourceLoc
-    diagnose(userSourceLoc, diagID)
+    if let userSourceLoc = operand.instruction.location.sourceLoc {
+      diagnose(userSourceLoc, diagID)
+    }
   }
 
-  // Identify the dependence scope.
+  // Identify the dependence scope. If no source location is found, bypass this diagnostic.
   func reportScope() {
-    if case let .access(beginAccess) = dependence.scope {
-      let parentVar = LifetimeVariable(dependent: beginAccess, context)
-      if let sourceLoc = beginAccess.location.sourceLoc ?? parentVar.sourceLoc {
-        diagnose(sourceLoc, .lifetime_outside_scope_access,
-                 parentVar.name ?? "")
-      }
+    let parentVar = LifetimeVariable(definedBy: dependence.parentValue, context)
+    // First check if the dependency is limited to an access scope. If the access has no source location then
+    // fall-through to report possible dependence on an argument.
+    if parentVar.isAccessScope, let accessLoc = parentVar.sourceLoc {
+      diagnose(accessLoc, .lifetime_outside_scope_access, parentVar.name ?? "")
       return
     }
-    if let arg = dependence.parentValue as? Argument,
-       let varDecl = arg.varDecl,
-       let sourceLoc = arg.sourceLoc {
-      diagnose(sourceLoc, .lifetime_outside_scope_argument,
-               varDecl.userFacingName)
+    // If the argument does not have a source location (e.g. a synthesized accessor), report the function location. The
+    // function's source location is sufficient for argument diagnostics, but if the function has no location, don't
+    // report any scope.
+    if parentVar.isArgument, let argLoc = parentVar.sourceLoc ?? function.location.sourceLoc {
+      if parentVar.isClosureCapture {
+        diagnose(argLoc, .lifetime_outside_scope_capture)
+      } else if let parentName = parentVar.name {
+        diagnose(argLoc, .lifetime_outside_scope_argument, parentName)
+      } else {
+        diagnose(argLoc, .lifetime_outside_scope_synthesized_argument, parentVar.accessorKind ?? function.name)
+      }
       return
     }
-    let parentVar = LifetimeVariable(dependent: dependence.parentValue, context)
+    // Now diagnose dependencies on regular variable and value scopes.
+    // Thunks do not have a function location, so any scopes inside the thunk will be ignored.
     if let parentLoc = parentVar.sourceLoc {
       if let parentName = parentVar.name {
         diagnose(parentLoc, .lifetime_outside_scope_variable, parentName)
@@ -260,51 +324,101 @@ private struct DiagnoseDependence {
       }
     }
   }
+
+  func diagnoseImplicitFunction() {
+    guard let funcLoc = function.location.sourceLoc else {
+      return
+    }
+    if let kindName = {
+         if function.isInitializer {
+           return "init"
+         }
+         if function.isDeinitializer {
+           return "deinit"
+         }
+         return function.accessorKindName
+       }() {
+      diagnose(funcLoc, .implicit_function_note, kindName)
+    }
+  }
 }
 
 // Identify a best-effort variable declaration based on a defining SIL
 // value or any lifetime dependent use of that SIL value.
 private struct LifetimeVariable {
-  var varDecl: VarDecl?
-  var sourceLoc: SourceLoc?
+  var varDecl: VarDecl? = nil
+  var sourceLoc: SourceLoc? = nil
+  var isAccessScope: Bool = false
+  var isArgument: Bool = false
+  var isClosureCapture: Bool = false
+  var accessorKind: String?
+  var thunkKind: Function.ThunkKind = .noThunk
   
   var name: StringRef? {
     return varDecl?.userFacingName
   }
 
-  init(dependent value: Value, _ context: some Context) {
-    if value.type.isAddress {
-      self = Self(accessBase: value.accessBase, context)
+  init(usedBy operand: Operand, _ context: some Context) {
+    self = .init(dependent: operand.value, context)
+    // variable names like $return_value and $implicit_value don't have source locations.
+    // For @out arguments, the operand's location is the best answer.
+    // Otherwise, fall back to the function's location.
+    self.sourceLoc = self.sourceLoc ?? operand.instruction.location.sourceLoc
+      ?? operand.instruction.parentFunction.location.sourceLoc
+  }
+
+  init(definedBy value: Value, _ context: some Context) {
+    self = .init(dependent: value, context)
+    // Fall back to the function's location.
+    self.sourceLoc = self.sourceLoc ?? value.parentFunction.location.sourceLoc
+  }
+
+  private init(dependent value: Value, _ context: some Context) {
+    guard let introducer = getFirstVariableIntroducer(of: value, context) else {
       return
     }
-    if let firstIntroducer = getFirstVariableIntroducer(of: value, context) {
-      self = Self(introducer: firstIntroducer)
+    if introducer.type.isAddress {
+      if let beginAccess = introducer as? BeginAccessInst {
+        // Recurse through beginAccess to find the variable introducer rather than the variable access.
+        self = .init(dependent: beginAccess.address, context)
+        self.isAccessScope = true
+        // However, remember source location of the innermost access.
+        self.sourceLoc = beginAccess.location.sourceLoc ?? self.sourceLoc
+        return
+      }
+      self = .init(accessBase: introducer.accessBase, context)
       return
     }
-    self.varDecl = nil
-    self.sourceLoc = nil
+    self = Self(introducer: introducer, context)
   }
 
   private func getFirstVariableIntroducer(of value: Value, _ context: some Context) -> Value? {
     var introducer: Value?
-    var useDefVisitor = VariableIntroducerUseDefWalker(context, scopedValue: value) {
+    var useDefVisitor = VariableIntroducerUseDefWalker(context, scopedValue: value, ignoreTrivialCopies: false) {
       introducer = $0
       return .abortWalk
     }
     defer { useDefVisitor.deinitialize() }
-    _ = useDefVisitor.walkUp(valueOrAddress: value)
+    _ = useDefVisitor.walkUp(newLifetime: value)
     return introducer
   }
 
-  private init(introducer: Value) {
-    if let arg = introducer as? Argument {
-      self.varDecl = arg.varDecl
-    } else {
-      self.sourceLoc = introducer.definingInstruction?.location.sourceLoc
-      self.varDecl = introducer.definingInstruction?.findVarDecl()
+  private init(introducer: Value, _ context: some Context) {
+    if let arg = introducer as? FunctionArgument {
+      self.varDecl = arg.findVarDecl()
+      self.sourceLoc = arg.sourceLoc
+      self.isArgument = true
+      self.isClosureCapture = arg.isClosureCapture
+      return
     }
-    if let varDecl {
-      sourceLoc = varDecl.nameLoc
+    if let varDecl = introducer.definingInstruction?.findVarDecl() {
+      self.varDecl = varDecl
+      self.sourceLoc = varDecl.nameLoc
+    } else if let sourceLoc = introducer.definingInstruction?.location.sourceLoc {
+      self.sourceLoc = sourceLoc
+    } else {
+      self.accessorKind = introducer.parentFunction.accessorKindName
+      self.thunkKind = introducer.parentFunction.thunkKind
     }
   }
 
@@ -318,32 +432,27 @@ private struct LifetimeVariable {
       // never be produced by one of these, except when it is redundant with the `alloc_box` VarDecl. It does not seem
       // possible for a box to be moved/borrowed directly into another variable's box. Reassignment always loads/stores
       // the value.
-      self = Self(introducer: projectBox.box.referenceRoot)
+      self = .init(introducer: projectBox.box.referenceRoot, context)
     case .stack(let allocStack):
-      self = Self(introducer: allocStack)
+      self = .init(introducer: allocStack, context)
     case .global(let globalVar):
       self.varDecl = globalVar.varDecl
       self.sourceLoc = varDecl?.nameLoc
     case .class(let refAddr):
-      self.varDecl = refAddr.varDecl
-      self.sourceLoc = refAddr.location.sourceLoc
+      self = .init(introducer: refAddr, context)
     case .tail(let refTail):
-      self = Self(introducer: refTail.instance)
+      self = .init(introducer: refTail.instance, context)
     case .argument(let arg):
-      self.varDecl = arg.varDecl
-      self.sourceLoc = arg.sourceLoc
+      self = .init(introducer: arg, context)
     case .yield(let result):
       // TODO: bridge VarDecl for FunctionConvention.Yields
-      self.varDecl = nil
-      self.sourceLoc = result.parentInstruction.location.sourceLoc
+      self = .init(introducer: result, context)
     case .storeBorrow(let sb):
       self = .init(dependent: sb.source, context)
     case .pointer(let ptrToAddr):
-      self.varDecl = nil
-      self.sourceLoc = ptrToAddr.location.sourceLoc
+      self = .init(introducer: ptrToAddr, context)
     case .index, .unidentified:
-      self.varDecl = nil
-      self.sourceLoc = nil
+      break
     }
   }
 }
@@ -355,8 +464,8 @@ private struct LifetimeVariable {
 ///
 /// This supports store-to-yield. Storing to a yield is an escape unless the yielded memory location depends on another
 /// lifetime that already depends on the current scope. When setter depends on 'newValue', 'newValue' is stored to the
-/// yielded address, and the yielded addrses depends on the lifetime of 'self'. A mark_dependence should have already
-/// been inserted for that lifetime depenence:
+/// yielded address, and the yielded addresses depends on the lifetime of 'self'. A mark_dependence should have already
+/// been inserted for that lifetime dependence:
 ///
 ///   (%a, %t) = begin_apply %f(%self)
 ///              : $@yield_once @convention(method) (@inout Self) -> _inherit(0) @yields @inout Self.field
@@ -392,7 +501,7 @@ extension DependentAddressUseDefWalker: AddressUseDefWalker {
   }
 }
 
-/// Walk down lifetime depenence uses. For each check that all dependent
+/// Walk down lifetime dependence uses. For each check that all dependent
 /// leaf uses are non-escaping and within the dependence scope. The walk
 /// starts with add address for .access dependencies. The walk can
 /// transition from an address to a value at a load. The walk can
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceInsertion.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceInsertion.swift
index 61ffbee1a612c..a2547d21fdd37 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceInsertion.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceInsertion.swift
@@ -95,6 +95,7 @@ extension LifetimeDependentApply {
   struct LifetimeSource {
     let targetKind: TargetKind
     let convention: LifetimeDependenceConvention
+    let isInout: Bool
     let value: Value
   }
 
@@ -116,7 +117,8 @@ extension LifetimeDependentApply {
       guard let dep = applySite.resultDependence(on: operand) else {
         continue
       }
-      info.sources.push(LifetimeSource(targetKind: .result, convention: dep, value: operand.value))
+      let isInout = applySite.convention(of: operand)?.isInout ?? false
+      info.sources.push(LifetimeSource(targetKind: .result, convention: dep, isInout: isInout, value: operand.value))
     }
     return info
   }
@@ -135,6 +137,7 @@ extension LifetimeDependentApply {
         ? TargetKind.yieldAddress : TargetKind.yield
       info.sources.push(LifetimeSource(targetKind: targetKind,
                                        convention: .scope(addressable: false, addressableForDeps: false),
+                                       isInout: false,
                                        value: beginApply.token))
     }
     for operand in applySite.parameterOperands {
@@ -145,9 +148,15 @@ extension LifetimeDependentApply {
       case .inherit:
         continue
       case .scope:
+        // FIXME: For yields with a scoped lifetime dependence, dependence on parameter operands is redundant,
+        // since we introduce dependence on the begin_apply's token as well.
+        // This can lead to duplicate lifetime dependence diagnostics in some cases.
+        // However this is neccessary for safety when begin_apply gets inlined which will delete the dependence on the token.
         for yieldedValue in beginApply.yieldedValues {
           let targetKind = yieldedValue.type.isAddress ? TargetKind.yieldAddress : TargetKind.yield
-          info.sources.push(LifetimeSource(targetKind: targetKind, convention: .inherit, value: operand.value))
+          let isInout = applySite.convention(of: operand)?.isInout ?? false
+          info.sources.push(LifetimeSource(targetKind: targetKind, convention: dep, isInout: isInout,
+                                           value: operand.value))
         }
       }
     }
@@ -176,7 +185,8 @@ extension LifetimeDependentApply {
       guard let dep = dep else {
         continue
       }
-      info.sources.push(LifetimeSource(targetKind: targetKind, convention: dep, value: operand.value))
+      let isInout = applySite.convention(of: operand)?.isInout ?? false
+      info.sources.push(LifetimeSource(targetKind: targetKind, convention: dep, isInout: isInout, value: operand.value))
     }
     return info
   }
@@ -191,8 +201,8 @@ private extension LifetimeDependentApply.LifetimeSourceInfo {
       // (a) the result or yield is never returned from this function
       //
       // (b) the inherited lifetime has a dependence root within this function (it comes from a dependent function
-      // argument or scoped dependence). In this case, when that depedence root is diagnosed, the analysis will find
-      // transtive uses of this apply's result.
+      // argument or scoped dependence). In this case, when that dependence root is diagnosed, the analysis will find
+      // transitive uses of this apply's result.
       //
       // (c) the dependent value is passed to another call with a dependent inout argument, or it is stored to a yielded
       // address of a coroutine that has a dependent inout argument. In this case, a mark_dependence will already be
@@ -219,8 +229,8 @@ private extension LifetimeDependentApply.LifetimeSourceInfo {
         return
       }
       // Create a new dependence on the apply's access to the argument.
-      for varIntoducer in gatherVariableIntroducers(for: source.value, context) {
-        let scope = LifetimeDependence.Scope(base: varIntoducer, context)
+      for varIntroducer in gatherVariableIntroducers(for: source.value, ignoreTrivialCopies: !source.isInout, context) {
+        let scope = LifetimeDependence.Scope(base: varIntroducer, context)
         log("Scoped lifetime from \(source.value)")
         log("  scope: \(scope)")
         bases.append(scope.parentValue)
@@ -247,18 +257,21 @@ private func insertResultDependencies(for apply: LifetimeDependentApply, _ conte
     insertMarkDependencies(value: dependentValue, initializer: nil, bases: sources.bases, builder: builder, context)
   }
   for resultOper in apply.applySite.indirectResultOperands {
-    let accessBase = resultOper.value.accessBase
-    guard case let .store(initializingStore, initialAddress) = accessBase.findSingleInitializer(context) else {
-      continue
+    guard let initialAddress = resultOper.value.accessBase.address else {
+      diagnoseUnknownDependenceSource(sourceLoc: apply.applySite.location.sourceLoc, context)
+      return
     }
-    assert(initializingStore == resultOper.instruction, "an indirect result is a store")
     Builder.insert(after: apply.applySite, context) { builder in
-      insertMarkDependencies(value: initialAddress, initializer: initializingStore, bases: sources.bases,
+      insertMarkDependencies(value: initialAddress, initializer: resultOper.instruction, bases: sources.bases,
                              builder: builder, context)
     }
   }
 }
 
+private func diagnoseUnknownDependenceSource(sourceLoc: SourceLoc?, _ context: FunctionPassContext) {
+  context.diagnosticEngine.diagnose(.lifetime_value_outside_scope, at: sourceLoc)
+}
+
 private func insertParameterDependencies(apply: LifetimeDependentApply, target: Operand,
                                          _ context: FunctionPassContext ) {
   guard var sources = apply.getParameterDependenceSources(target: target) else {
@@ -300,8 +313,8 @@ private func insertMarkDependencies(value: Value, initializer: Instruction?,
   }
 }
 
-/// Walk up the value dependence chain to find the best-effort variable declaration. Typically called while diagnosing
-/// an error.
+/// Walk up the value dependence chain to find the best-effort variable declaration. Used to find the source of a borrow
+/// dependence or to print the source variable in a diagnostic message.
 ///
 /// Returns an array with at least one introducer value.
 ///
@@ -309,16 +322,17 @@ private func insertMarkDependencies(value: Value, initializer: Instruction?,
 /// - a variable declaration (begin_borrow [var_decl], move_value [var_decl])
 /// - a begin_access for a mutable variable access
 /// - the value or address "root" of the dependence chain
-func gatherVariableIntroducers(for value: Value, _ context: Context)
+func gatherVariableIntroducers(for value: Value, ignoreTrivialCopies: Bool, _ context: Context)
   -> SingleInlineArray<Value>
 {
   var introducers = SingleInlineArray<Value>()
-  var useDefVisitor = VariableIntroducerUseDefWalker(context, scopedValue: value) {
+  var useDefVisitor = VariableIntroducerUseDefWalker(context, scopedValue: value,
+                                                     ignoreTrivialCopies: ignoreTrivialCopies) {
     introducers.push($0)
     return .continueWalk
   }
   defer { useDefVisitor.deinitialize() }
-  _ = useDefVisitor.walkUp(valueOrAddress: value)
+  _ = useDefVisitor.walkUp(newLifetime: value)
   assert(!introducers.isEmpty, "missing variable introducer")
   return introducers
 }
@@ -330,7 +344,7 @@ func gatherVariableIntroducers(for value: Value, _ context: Context)
 /// Walk up lifetime dependencies to the first value associated with a variable declaration.
 ///
 /// To start walking:
-///     walkUp(valueOrAddress: Value) -> WalkResult
+///     walkUp(newLifetime: Value) -> WalkResult
 ///
 /// This utility finds the value or address associated with the lvalue (variable declaration) that is passed as the
 /// source of a lifetime dependent argument. If no lvalue is found, then it finds the "root" of the chain of temporary
@@ -343,7 +357,7 @@ func gatherVariableIntroducers(for value: Value, _ context: Context)
 ///
 ///     dependsOn(lvalue.computed) // finds the temporary value directly returned by a getter.
 ///
-/// SILGen emits temporary copies that violate lifetime dependence semantcs. This utility looks through such temporary
+/// SILGen emits temporary copies that violate lifetime dependence semantics. This utility looks through such temporary
 /// copies, stopping at a value that introduces an immutable variable: move_value [var_decl] or begin_borrow [var_decl],
 /// or at an access of a mutable variable: begin_access [read] or begin_access [modify].
 ///
@@ -382,10 +396,7 @@ func gatherVariableIntroducers(for value: Value, _ context: Context)
 /// All of the dependent uses including `end_borrow %5` and `destroy_value %4` must be before the end of the dependence
 /// scope: `destroy_value %parent`. In this case, the dependence parent is an owned value, so the scope is simply the
 /// value's OSSA lifetime.
-struct VariableIntroducerUseDefWalker : ForwardingUseDefWalker {
-  // The ForwardingUseDefWalker's context is the most recent lifetime owner.
-  typealias PathContext = Value?
-
+struct VariableIntroducerUseDefWalker : LifetimeDependenceUseDefValueWalker, LifetimeDependenceUseDefAddressWalker {
   let context: Context
 
   // If the scoped value is trivial, then only the variable's lexical scope is relevant, and access scopes can be
@@ -399,11 +410,15 @@ struct VariableIntroducerUseDefWalker : ForwardingUseDefWalker {
   // Call \p visit rather than calling this directly.
   private let visitorClosure: (Value) -> WalkResult
 
-  init(_ context: Context, scopedValue: Value, _ visitor: @escaping (Value) -> WalkResult) {
+  init(_ context: Context, scopedValue: Value, ignoreTrivialCopies: Bool, _ visitor: @escaping (Value) -> WalkResult) {
     self.context = context
-    self.isTrivialScope = scopedValue.type.isAddress
-      ? scopedValue.type.objectType.isTrivial(in: scopedValue.parentFunction)
-      : scopedValue.isTrivial(context)
+    if ignoreTrivialCopies {
+      self.isTrivialScope = scopedValue.type.isAddress
+        ? scopedValue.type.objectType.isTrivial(in: scopedValue.parentFunction)
+        : scopedValue.isTrivial(context)
+    } else {
+      self.isTrivialScope = false
+    }
     self.visitedValues = ValueSet(context)
     self.visitorClosure = visitor
   }
@@ -412,128 +427,55 @@ struct VariableIntroducerUseDefWalker : ForwardingUseDefWalker {
     visitedValues.deinitialize()
   }
  
-  mutating func needWalk(for value: Value, _ owner: Value?) -> Bool {
-    visitedValues.insert(value)
-  }
-
   mutating func introducer(_ value: Value, _ owner: Value?) -> WalkResult {
+    if let addrToPtr = value as? AddressToPointerInst {
+      // AddressToPointer introduces the value dependence. To handle Builtin.addressOfBorrow, follow the address that
+      // the pointer is derived from.
+      return walkUp(address: addrToPtr.address)
+    }
     return visitorClosure(value)
   }
 
-  mutating func walkUp(valueOrAddress: Value) -> WalkResult {
-    if valueOrAddress.type.isAddress {
-      return walkUp(address: valueOrAddress)
-    }
-    return walkUp(newLifetime: valueOrAddress)
+  mutating func addressIntroducer(_ address: Value, access: AccessBaseAndScopes) -> WalkResult {
+    return visitorClosure(address)
+  }
+
+  mutating func needWalk(for value: Value, _ owner: Value?) -> Bool {
+    visitedValues.insert(value)
+  }
+
+  mutating func needWalk(for address: Value) -> Bool {
+    visitedValues.insert(address)
   }
-}
 
-// Helpers
-extension VariableIntroducerUseDefWalker {
   mutating func walkUp(newLifetime: Value) -> WalkResult {
+    if newLifetime.type.isAddress {
+      return walkUp(address: newLifetime)
+    }
     let newOwner = newLifetime.ownership == .owned ? newLifetime : nil
     return walkUp(value: newLifetime, newOwner)
   }
 
+  /// Override to check for variable introducers: move_value, begin_value, before following
+  /// OwnershipTransitionInstruction.
   mutating func walkUp(value: Value, _ owner: Value?) -> WalkResult {
-    // Check for variable introducers: move_value, begin_value, before following OwnershipTransitionInstruction.
     if let inst = value.definingInstruction, VariableScopeInstruction(inst) != nil {
       return visitorClosure(value)
     }
-    switch value.definingInstruction {
-    case let transition as OwnershipTransitionInstruction:
-      return walkUp(newLifetime: transition.operand.value)
-    case let load as LoadInstruction:
-      return walkUp(address: load.address)
-    default:
-      break
-    }
-    // If the dependence chain has a phi, consider it a root. Dependence roots dominate all dependent values.
-    if Phi(value) != nil {
-      return introducer(value, owner)
-    }
-    // ForwardingUseDefWalker will callback to introducer() when it finds no forwarding instruction.
-    return walkUpDefault(forwarded: value, owner)
+    return walkUpDefault(value: value, owner)
   }
 
-  // Handle temporary allocations and access scopes.
-  mutating func walkUp(address: Value) -> WalkResult {
-    let accessBaseAndScopes = address.accessBaseWithScopes
-    // Continue walking for some kinds of access base.
-    switch accessBaseAndScopes.base {
-    case .box, .global, .class, .tail, .pointer, .index, .unidentified:
-      break
-    case let .stack(allocStack):
-      if allocStack.varDecl == nil {
-        // Ignore temporary stack locations. Their access scopes do not affect lifetime dependence.
-        return walkUp(stackInitializer: allocStack, at: address)
-      }
-    case let .argument(arg):
-      // Ignore access scopes for @in or @in_guaranteed arguments when all scopes are reads. Do not ignore a [read]
-      // access of an inout argument or outer [modify]. Mutation later with the outer scope could invalidate the
-      // borrowed state in this narrow scope. Do not ignore any mark_depedence on the address.
-      if arg.convention.isIndirectIn && accessBaseAndScopes.isOnlyReadAccess {
-        return introducer(arg, nil)
-      }
-      // @inout arguments may be singly initialized (when no modification exists in this function), but this is not
-      // relevant here because they require nested access scopes which can never be ignored.
-    case let .yield(yieldedAddress):
-      // Ignore access scopes for @in or @in_guaranteed yields when all scopes are reads.
-      let apply = yieldedAddress.definingInstruction as! FullApplySite
-      if apply.convention(of: yieldedAddress).isIndirectIn && accessBaseAndScopes.isOnlyReadAccess {
-        return introducer(yieldedAddress, nil)
-      }
-    case .storeBorrow(let sb):
-      // Walk up through a store into a temporary.
-      if accessBaseAndScopes.scopes.isEmpty,
-         case .stack = sb.destinationOperand.value.accessBase {
-        return walkUp(newLifetime: sb.source)
-      }
-    }
-    // Skip the access scope for unsafe[Mutable]Address. Treat it like a projection of 'self' rather than a separate
-    // variable access.
-    if case let .access(innerAccess) = accessBaseAndScopes.scopes.first,
-       let addressorSelf = innerAccess.unsafeAddressorSelf {
-      return walkUp(valueOrAddress: addressorSelf)
-    }
-    // Ignore the acces scope for trivial values regardless of whether it is singly-initialized. Trivial values do not
-    // need to be kept alive in memory and can be safely be overwritten in the same scope. Lifetime dependence only
-    // cares that the loaded value is within the lexical scope of the trivial value's variable declaration. Rather than
-    // skipping all access scopes, call 'walkUp' on each nested access in case one of them needs to redirect the walk,
-    // as required for 'access.unsafeAddressorSelf'.
-    if isTrivialScope {
-      switch accessBaseAndScopes.scopes.first {
-      case .none, .base:
-        break
-      case let .access(beginAccess):
-        return walkUp(address: beginAccess.address)
-      case let .dependence(markDep):
-        return walkUp(address: markDep.value)
-      }
-    }
-    return introducer(accessBaseAndScopes.enclosingAccess.address ?? address, nil)
-  }
-
-  // Handle singly-initialized temporary stack locations.
-  mutating func walkUp(stackInitializer allocStack: AllocStackInst, at address: Value) -> WalkResult {
-    guard let initializer = allocStack.accessBase.findSingleInitializer(context) else {
-      return introducer(address, nil)
-    }
-    if case let .store(store, _) = initializer {
-      switch store {
-      case let store as StoringInstruction:
-        return walkUp(newLifetime: store.source)
-      case let srcDestInst as SourceDestAddrInstruction:
-        return walkUp(address: srcDestInst.destination)
-      case let apply as FullApplySite:
-        if let f = apply.referencedFunction, f.isConvertPointerToPointerArgument {
-          return walkUp(address: apply.parameterOperands[0].value)
+  /// Override to check for on-stack variables before following an initializer.
+  mutating func walkUp(address: Value, access: AccessBaseAndScopes) -> WalkResult {
+    // Check for stack locations that correspond to an lvalue if there isn't any nested access scope.
+    if access.innermostAccess == nil {
+      if case let .stack(allocStack) = access.base {
+        if allocStack.varDecl != nil {
+          return addressIntroducer(allocStack, access: access)
         }
-      default:
-        break
       }
     }
-    return introducer(address, nil)
+    return walkUpDefault(address: address, access: access)
   }
 }
 
@@ -541,5 +483,5 @@ let variableIntroducerTest = FunctionTest("variable_introducer") {
     function, arguments, context in
   let value = arguments.takeValue()
   print("Variable introducers of: \(value)")
-  print(gatherVariableIntroducers(for: value, context))
+  print(gatherVariableIntroducers(for: value, ignoreTrivialCopies: false, context))
 }
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceScopeFixup.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceScopeFixup.swift
index ecb69fde5b197..94dfc78e820ba 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceScopeFixup.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceScopeFixup.swift
@@ -106,6 +106,7 @@ let lifetimeDependenceScopeFixupPass = FunctionPass(
 
   let localReachabilityCache = LocalVariableReachabilityCache()
 
+  var mustFixStackNesting = false
   for instruction in function.instructions {
     guard let markDep = instruction as? MarkDependenceInstruction else {
       continue
@@ -116,12 +117,100 @@ let lifetimeDependenceScopeFixupPass = FunctionPass(
     // Redirect the dependence base to ignore irrelevant borrow scopes.
     let newLifetimeDep = markDep.rewriteSkippingBorrow(scope: innerLifetimeDep.scope, context)
 
-    // Recursively sink enclosing end_access, end_borrow, or end_apply.
-    let args = extendScopes(dependence: newLifetimeDep, localReachabilityCache, context)
+    // Recursively sink enclosing end_access, end_borrow, end_apply, and destroy_value. If the scope can be extended
+    // into the caller, return the function arguments that are the dependency sources.
+    var scopeExtension = ScopeExtension(localReachabilityCache, context)
+    guard scopeExtension.extendScopes(dependence: newLifetimeDep) else {
+      continue
+    }
+    mustFixStackNesting = mustFixStackNesting || scopeExtension.mustFixStackNesting
+    let args = scopeExtension.findArgumentDependencies()
+
+    // If the scope cannot be extended to the caller, this must be the outermost dependency level.
+    // Insert end_cow_mutation_addr if needed.
+    if args.isEmpty {
+      createEndCOWMutationIfNeeded(lifetimeDep: newLifetimeDep, context)
+    }
 
     // Redirect the dependence base to the function arguments. This may create additional mark_dependence instructions.
     markDep.redirectFunctionReturn(to: args, context)
   }
+  if mustFixStackNesting {
+    context.fixStackNesting(in: function)
+  }
+}
+
+private extension Type {
+  func mayHaveMutableSpan(in function: Function, _ context: FunctionPassContext) -> Bool {
+    if hasArchetype {
+      return true
+    }
+    if isBuiltinType {
+      return false
+    }
+    // Only result types that are nominal can have a MutableSpan derived from an inout array access.
+    if nominal == nil {
+      return false
+    }
+    if nominal == context.swiftMutableSpan {
+      return true
+    }
+    if isStruct {
+      guard let fields = getNominalFields(in: function) else {
+        return false
+      }
+      return fields.contains { $0.mayHaveMutableSpan(in: function, context) }
+    }
+    if isTuple {
+      return tupleElements.contains { $0.mayHaveMutableSpan(in: function, context) }
+    }
+    if isEnum {
+      guard let cases = getEnumCases(in: function) else {
+        return true
+      }
+      return cases.contains { $0.payload?.mayHaveMutableSpan(in: function, context) ?? false }
+    }
+    // Classes cannot be ~Escapable, therefore cannot hold a MutableSpan.
+    if isClass {
+      return false
+    }
+    return false
+  }
+}
+
+/// Insert end_cow_mutation_addr for lifetime dependent values that maybe of type MutableSpan and depend on a mutable address.
+private func createEndCOWMutationIfNeeded(lifetimeDep: LifetimeDependence, _ context: FunctionPassContext) {
+  var scoped : ScopedInstruction
+
+  // Handle cases which generate mutable addresses: begin_access [modify] and yield &
+  switch lifetimeDep.scope {
+    case let .access(beginAccess):
+      if beginAccess.accessKind != .modify {
+        return
+      }
+      scoped = beginAccess
+    case let .yield(value):
+      let beginApply = value.definingInstruction as! BeginApplyInst
+      if value == beginApply.token {
+        return
+      }
+      if beginApply.convention(of: value as! MultipleValueInstructionResult) != .indirectInout {
+        return
+      }
+      scoped = beginApply
+    // None of the below cases can generate a mutable address.
+    case .owned, .borrowed, .local, .initialized, .caller, .global, .unknown:
+      return
+  }
+
+  guard lifetimeDep.dependentValue.type.mayHaveMutableSpan(in: lifetimeDep.dependentValue.parentFunction, context) else {
+    return
+  }
+
+  for endInstruction in scoped.endInstructions {
+    let builder = Builder(before: endInstruction, context)
+    builder.createEndCOWMutationAddr(address: lifetimeDep.parentValue)
+  }
 }
 
 private extension MarkDependenceInstruction {
@@ -189,6 +278,34 @@ private extension MarkDependenceAddrInst {
   }
 }
 
+/// A scope extension is a set of nested scopes and their owners. The owner is a value that represents ownership of
+/// the outermost scopes, which cannot be extended; it limits how far the nested scopes can be extended.
+private struct ScopeExtension {
+  let context: FunctionPassContext
+  let localReachabilityCache: LocalVariableReachabilityCache
+
+  /// The ownership lifetime of the dependence base, which cannot be extended.
+  var owners = SingleInlineArray<Value>()
+
+  // Initialized after walking dependent uses. True if the scope can be extended into the caller.
+  var dependsOnCaller: Bool?
+
+  // Does scope extension potentially invalidate stack nesting?
+  var mustFixStackNesting = false
+
+  // Scopes listed in RPO over an upward walk. The outermost scope is first.
+  var scopes = SingleInlineArray<ExtendableScope>()
+
+  var innermostScope: ExtendableScope { get { scopes.last! } }
+
+  var visitedValues: ValueSet?
+
+  init(_ localReachabilityCache: LocalVariableReachabilityCache, _ context: FunctionPassContext) {
+    self.localReachabilityCache = localReachabilityCache
+    self.context = context
+  }
+}
+
 /// Transitively extend nested scopes that enclose the dependence base.
 ///
 /// If the parent function returns the dependent value, then this returns the function arguments that represent the
@@ -218,215 +335,270 @@ private extension MarkDependenceAddrInst {
 // access. This scope fixup pass must extend '%a1' to cover the `@useDependent` but must not extend the base of the
 // `mark_dependence` to the outer access `%0`. This ensures that exclusivity diagnostics correctly reports the
 // violation, and that subsequent optimizations do not shrink the inner access `%a1`.
-private func extendScopes(dependence: LifetimeDependence,
-                          _ localReachabilityCache: LocalVariableReachabilityCache,
-                          _ context: FunctionPassContext) -> SingleInlineArray<FunctionArgument> {
-  log("Scope fixup for lifetime dependent instructions: \(dependence)")
-
-  // Each scope extension is a set of nested scopes and an owner. The owner is a value that represents ownerhip of the
-  // outermost scope, which cannot be extended; it limits how far the nested scopes can be extended.
-  guard let scopeExtensions = dependence.scope.gatherExtensions(context) else {
-    return SingleInlineArray()
-  }
-  var dependsOnArgs = SingleInlineArray<FunctionArgument>()
-  for scopeExtension in scopeExtensions {
-    var scopeExtension = scopeExtension
-    guard var useRange = computeDependentUseRange(of: dependence, within: &scopeExtension, localReachabilityCache,
-                                                  context) else {
-      continue
-    }
+extension ScopeExtension {
+  mutating func extendScopes(dependence: LifetimeDependence) -> Bool {
+    log("Scope fixup for lifetime dependent instructions:\n\(dependence)")
 
-    // deinitializes 'useRange'
-    guard scopeExtension.tryExtendScopes(over: &useRange, context) else {
-      continue
+    gatherExtensions(dependence: dependence)
+
+    // computeDependentUseRange initializes scopeExtension.dependsOnCaller.
+    guard var useRange = computeDependentUseRange(of: dependence) else {
+      return false
     }
-    if scopeExtension.dependsOnCaller, let arg = scopeExtension.dependsOnArg {
-      dependsOnArgs.push(arg)
+    // tryExtendScopes deinitializes 'useRange'
+    var scopesToExtend = SingleInlineArray<ExtendableScope>()
+    guard canExtendScopes(over: &useRange, scopesToExtend: &scopesToExtend) else {
+      useRange.deinitialize()
+      return false
     }
+    // extend(over:) must receive the original unmodified `useRange`, without intermediate scope ending instructions.
+    // This deinitializes `useRange` before erasing instructions.
+    extend(scopesToExtend: scopesToExtend, over: &useRange, context)
+    return true
   }
-  return dependsOnArgs
 }
 
-/// All scopes nested within a single dependence base that require extension.
-private struct ScopeExtension {
-  /// The ownership lifetime of the dependence base, which cannot be extended.
-  let owner: Value
+// TODO: add parent and child indices to model a DAG of scopes. This will allow sibling scopes that do not follow a
+// stack discipline among them but still share the same parent and child scopes. This can occur with dependencies on
+// multiple call operands. Until then, scope extension may bail out unnecessarily while trying to extend over a sibling
+// scope.
+private struct ExtendableScope {
+  enum Introducer {
+    case scoped(ScopedInstruction)
+    case stack(Instruction)
+    case owned(Value)
+  }
 
-  /// The scopes nested under 'value' that may be extended, in inside-out order. There is always at
-  /// least one element, otherwise there is nothing to consider extending.
-  let nestedScopes: SingleInlineArray<LifetimeDependence.Scope>
+  // scope.allocStackInstruction is always valid for Introducer.allocStack and is valid for Introducer.scoped when
+  // ScopedInstruction is a store_borrow.
+  let scope: LifetimeDependence.Scope
+  let introducer: Introducer
+
+  var firstInstruction: Instruction {
+    switch introducer {
+    case let .scoped(scopedInst):
+      return scopedInst
+    case let .stack(initializingStore):
+      return initializingStore
+    case let .owned(value):
+      if let definingInst = value.definingInstructionOrTerminator {
+        return definingInst
+      }
+      return value.parentBlock.instructions.first!
+    }
+  }
 
-  var innerScope: LifetimeDependence.Scope { get { nestedScopes.first! } }
+  var endInstructions: LazyMapSequence<LazyFilterSequence<UseList>, Instruction> {
+    switch introducer {
+    case let .scoped(scopedInst):
+      return scopedInst.scopeEndingOperands.users
+    case .stack:
+      // For alloc_stack without a store-borrow scope, include the deallocs in its scope to ensure that we never shorten
+      // the original allocation. It's possible that some other use depends on the address.
+      //
+      // Same as 'AllocStackInst.deallocations' but as an Instruction list...
+      return scope.allocStackInstruction!.uses.lazy.filter
+      { $0.instruction is DeallocStackInst }.lazy.map { $0.instruction }
+
+    case let .owned(value):
+      return value.uses.endingLifetime.users
+    }
+  }
 
-  /// `dependsOnArg` is set to the function argument that represents the caller's dependency source.
-  ///
-  /// Note: for non-address owners, this is equivalent to: owner as? FunctionArg?
-  var dependsOnArg: FunctionArgument?
+  var deallocs: LazyMapSequence<LazyFilterSequence<UseList>, DeallocStackInst>? {
+    guard let allocStack = scope.allocStackInstruction else {
+      return nil
+    }
+    return allocStack.deallocations
+  }
 
-  /// `dependsOnCaller` is true if the dependent value is returned by the function.
-  /// Initialized during computeDependentUseRange().
-  var dependsOnCaller = false
-}
+  // Allow scope extension as long as `beginInst` does not define a variable scope and is either a scoped instruction or
+  // a store to a singly-initialized temporary.
+  init?(_ scope: LifetimeDependence.Scope, beginInst: Instruction?) {
+    self.scope = scope
+    guard let beginInst = beginInst, VariableScopeInstruction(beginInst) == nil else {
+      return nil
+    }
+    // Check for "scoped" store_borrow extension before checking allocStackInstruction.
+    if let scopedInst = beginInst as? ScopedInstruction {
+      self.introducer = .scoped(scopedInst)
+      return
+    }
+    if scope.allocStackInstruction != nil {
+      self.introducer = .stack(beginInst)
+      return
+    }
+    return nil
+  }
 
-private extension LifetimeDependence.Scope {
-  /// The instruction that introduces an extendable scope. This returns a non-nil scope introducer for
-  /// each scope in ScopeExtension.nestedScopes.
-  var extendableBegin: ScopedInstruction? {
-    switch self {
-    case let .access(beginAccess):
-      return beginAccess
-    case let .borrowed(beginBorrow):
-      return beginBorrow.value.definingInstruction as? ScopedInstruction
-    case let .yield(yieldedValue):
-      return yieldedValue.definingInstruction as? ScopedInstruction
-    case let .initialized(initializer):
-      switch initializer {
-      case let .store(initializingStore: store, initialAddress: _):
-        if let sb = store as? StoreBorrowInst {
-          return sb
-        }
-        return nil
-      case .argument, .yield:
-        // TODO: extend indirectly yielded scopes.
-        return nil
-      }
-    default:
+  // Allow extension of owned temporaries that
+  // (a) are Escapable
+  // (b) do not define a variable scope
+  // (c) are only consumed by destroy_value
+  init?(_ scope: LifetimeDependence.Scope, owner: Value) {
+    self.scope = scope
+    // TODO: allow extension of lifetime dependent values by implementing a ScopeExtensionWalker that extends
+    // LifetimeDependenceUseDefWalker.
+    guard owner.type.isEscapable(in: owner.parentFunction),
+          VariableScopeInstruction(owner.definingInstruction) == nil,
+          owner.uses.endingLifetime.allSatisfy({ $0.instruction is DestroyValueInst }) else {
       return nil
     }
+    self.introducer = .owned(owner)
   }
+}
 
-  /// Precondition: the 'self' scope encloses a dependent value. 'innerScopes' are the extendable scopes enclosed by
-  /// 'self' that also enclose the dependent value.
-  ///
-  /// Gather the list of ScopeExtensions. Each extension is a list of scopes, including 'innerScopes', 'self' and,
-  /// recursively, any of its enclosing scopes that are extendable. We may have multiple extensions because a scope
-  /// introducer may itself depend on multiple operands.
-  ///
-  /// Return 'nil' if 'self' is not extendable.
-  func gatherExtensions(innerScopes: SingleInlineArray<LifetimeDependence.Scope>? = nil, _ context: FunctionPassContext)
-    -> SingleInlineArray<ScopeExtension>? {
+// Gather extendable scopes.
+extension ScopeExtension {
+  mutating func gatherExtensions(dependence: LifetimeDependence) {
+    visitedValues = ValueSet(context)
+    defer {
+      visitedValues!.deinitialize()
+      visitedValues = nil
+    }
+    gatherExtensions(scope: dependence.scope)
+  }
+
+  mutating func gatherExtensions(valueOrAddress: Value) {
+    if visitedValues!.insert(valueOrAddress) {
+      gatherExtensions(scope: LifetimeDependence.Scope(base: valueOrAddress, context))
+    }
+  }
 
-    // Note: LifetimeDependence.Scope.extend() will assume that all inner scopes begin with a ScopedInstruction.
-    var innerScopes = innerScopes ?? SingleInlineArray()
-    switch self {
+  mutating func nonExtendable(_ scope: LifetimeDependence.Scope) {
+    owners.push(scope.parentValue)
+  }
+
+  // If `scope` is extendable, find its owner or outer scopes first, then push for extension.
+  mutating func gatherExtensions(scope: LifetimeDependence.Scope) {
+    switch scope {
     case let .access(beginAccess):
-      return gatherAccessExtension(beginAccess: beginAccess, innerScopes: &innerScopes, context)
+      gatherAccessExtensions(beginAccess: beginAccess)
+      return
 
     case let .borrowed(beginBorrow):
-      // begin_borrow is extendable, so push this scope.
-      innerScopes.push(self)
-      return gatherBorrowExtension(borrowedValue: beginBorrow.baseOperand!.value, innerScopes: innerScopes, context)
-
-    case let .yield(yieldedValue):
-      // A yield is extendable, so push this scope.
-      innerScopes.push(self)
-      // Create a separate ScopeExtension for each operand that the yielded value depends on.
-      var extensions = SingleInlineArray<ScopeExtension>()
-      let applySite = yieldedValue.definingInstruction as! BeginApplyInst
-      for operand in applySite.parameterOperands {
-        guard let dep = applySite.resultDependence(on: operand), dep.isScoped else {
-          continue
+      if let beginInst = beginBorrow.value.definingInstruction {
+        if let extScope = ExtendableScope(scope, beginInst: beginInst) {
+          gatherExtensions(valueOrAddress: beginBorrow.baseOperand!.value)
+          scopes.push(extScope)
+          return
         }
-        // Pass a copy of innerScopes without modifying this one.
-        extensions.append(contentsOf: gatherOperandExtension(on: operand, innerScopes: innerScopes, context))
       }
-      return extensions
+
+    case let .yield(yieldedValue):
+      let beginApply = yieldedValue.definingInstruction as! BeginApplyInst
+      gatherYieldExtension(beginApply)
+      scopes.push(ExtendableScope(scope, beginInst: beginApply)!)
+      return
+
     case let .initialized(initializer):
       switch initializer {
       case let .store(initializingStore: store, initialAddress: _):
         if let sb = store as? StoreBorrowInst {
-          innerScopes.push(self)
-          // Only follow the source of the store_borrow. The address is always an alloc_stack without any access scope.
-          return gatherBorrowExtension(borrowedValue: sb.source, innerScopes: innerScopes, context)
+          // Follow the stored value since the owner of the borrowed value needs to cover this allocation.
+          gatherExtensions(valueOrAddress: sb.source)
         }
-        return nil
+        if scope.allocStackInstruction != nil {
+          scopes.push(ExtendableScope(scope, beginInst: store)!)
+          return
+        }
+        break
       case .argument, .yield:
         // TODO: extend indirectly yielded scopes.
-        return nil
+        break
+      }
+    case let .owned(value):
+      if let extScope = ExtendableScope(scope, owner: value) {
+        scopes.push(extScope)
+        return
+      }
+
+    case let .local(varInst):
+      switch varInst {
+      case let .beginBorrow(beginBorrow):
+        if let extScope = ExtendableScope(scope, beginInst: beginBorrow) {
+          gatherExtensions(valueOrAddress: beginBorrow.operand.value)
+          scopes.push(extScope)
+          return
+        }
+
+      case let .moveValue(moveValue):
+        if let extScope = ExtendableScope(scope, owner: moveValue) {
+          scopes.push(extScope)
+          return
+        }
       }
     default:
-      return nil
+      break
     }
+    nonExtendable(scope)
   }
 
-  /// Unlike LifetimeDependenceInsertion this does not use gatherVariableIntroducers. The purpose here is to extend
-  /// any enclosing OSSA scopes as far as possible to achieve the longest possible owner lifetime, rather than to
-  /// find the "dependence root" for a call argument.
-  func gatherOperandExtension(on operand: Operand, innerScopes: SingleInlineArray<LifetimeDependence.Scope>,
-                              _ context: FunctionPassContext) -> SingleInlineArray<ScopeExtension> {
-    let enclosingScope = LifetimeDependence.Scope(base: operand.value, context)
-    if let extensions = enclosingScope.gatherExtensions(innerScopes: innerScopes, context) {
-      return extensions
+  /// Unlike LifetimeDependenceInsertion, this does not stop at an argument's "variable introducer" and does not stop at
+  /// an addressable parameter. The purpose here is to extend any enclosing OSSA scopes as far as possible to achieve
+  /// the longest possible owner lifetime, rather than to find the source-level lvalue for a call argument.
+  mutating func gatherYieldExtension(_ beginApply: BeginApplyInst) {
+    // Create a separate ScopeExtension for each operand that the yielded value depends on.
+    for operand in beginApply.parameterOperands {
+      gatherExtensions(valueOrAddress: operand.value)
     }
-    // This is the outermost scope to be extended because gatherExtensions did not find an enclosing scope.
-    return SingleInlineArray(element: getOuterExtension(owner: operand.value, nestedScopes: innerScopes, context))
   }
 
-  func getOuterExtension(owner: Value, nestedScopes: SingleInlineArray<LifetimeDependence.Scope>,
-                         _ context: FunctionPassContext) -> ScopeExtension {
-    let dependsOnArg = owner as? FunctionArgument
-    return ScopeExtension(owner: owner, nestedScopes: nestedScopes, dependsOnArg: dependsOnArg)
-  }
-
-  // Find the nested access scopes that may be extended as if they are the same access. This includes any combination of
-  // read/modify accesses, regardless of whether they may cause an exclusivity violation. The outer accesses will only
-  // be extended as far as required such that the innermost access coveres all dependent uses.
-  // Set ScopeExtension.dependsOnArg if the nested accesses are all compatible with the argument's convention. Then, if
-  // all nested accesses were extended to the return statement, it is valid to logically combine them into a single
-  // access for the purpose of diagnostinc lifetime dependence.
-  func gatherAccessExtension(beginAccess: BeginAccessInst,
-                             innerScopes: inout SingleInlineArray<LifetimeDependence.Scope>,
-                             _ context: FunctionPassContext) -> SingleInlineArray<ScopeExtension> {
-    // Finding the access base also finds all intermediate nested scopes; there is no need to recursively call
-    // gatherExtensions().
+  mutating func gatherAccessExtensions(beginAccess: BeginAccessInst) {
     let accessBaseAndScopes = beginAccess.accessBaseWithScopes
-    var isCompatibleAccess = true
-    for nestedScope in accessBaseAndScopes.scopes {
+    if let baseAddress = accessBaseAndScopes.base.address {
+      gatherExtensions(valueOrAddress: baseAddress)
+    }
+    for nestedScope in accessBaseAndScopes.scopes.reversed() {
       switch nestedScope {
       case let .access(nestedBeginAccess):
-        innerScopes.push(.access(nestedBeginAccess))
-        if nestedBeginAccess.accessKind != beginAccess.accessKind {
-          isCompatibleAccess = false
-        }
+        scopes.push(ExtendableScope(.access(nestedBeginAccess), beginInst: nestedBeginAccess)!)
       case .dependence, .base:
         // ignore recursive mark_dependence base for the purpose of extending scopes. This pass will extend the base
         // of that mark_dependence (if it is unresolved) later as a separate LifetimeDependence.Scope.
         break
       }
     }
-    guard case let .access(outerBeginAccess) = innerScopes.last else {
-      // beginAccess is included in accessBaseWithScopes; so at least one access was added to innerScopes.
-      fatalError("missing outer access")
+  }
+}
+
+extension ScopeExtension {
+  /// Check if the dependent value depends only on function arguments and can therefore be returned to caller. If so,
+  /// return the list of arguments that it depends on. If this returns an empty list, then the dependent value cannot be
+  /// returned.
+  ///
+  /// The conditions for returning a dependent value are:
+  /// - The dependent value is returned from this function.
+  /// - All nested scopes are access scopes that are redundant with the caller's exclusive access scope.
+  /// - All scope owners are function arguments.
+  func findArgumentDependencies() -> SingleInlineArray<FunctionArgument> {
+    let noCallerScope = SingleInlineArray<FunctionArgument>()
+    // Check that the dependent value is returned by this function.
+    if !dependsOnCaller! {
+      return noCallerScope
     }
-    if case let .argument(arg) = accessBaseAndScopes.base {
-      if isCompatibleAccess && beginAccess.accessKind.isCompatible(with: arg.convention) {
-        let scopes = ScopeExtension(owner: outerBeginAccess.address, nestedScopes: innerScopes, dependsOnArg: arg)
-        return SingleInlineArray(element: scopes)
+    // Check that all nested scopes that it depends on can be covered by exclusive access in the caller.
+    for extScope in scopes {
+      switch extScope.scope {
+      case .access:
+        break
+      default:
+        return noCallerScope
       }
     }
-    /// Recurse in case of indirect yields.
-    let enclosingScope = LifetimeDependence.Scope(base: outerBeginAccess.address, context)
-    if let extensions = enclosingScope.gatherExtensions(innerScopes: innerScopes, context) {
-      return extensions
-    }
-    // When the owner is an address, the owner's scope is considered the availability of its access base starting at the
-    // position of innerScopes.last.
-    let scopes = ScopeExtension(owner: outerBeginAccess.address, nestedScopes: innerScopes, dependsOnArg: nil)
-    return SingleInlineArray(element: scopes)
-  }
-
-  func gatherBorrowExtension(borrowedValue: Value,
-                             innerScopes: SingleInlineArray<LifetimeDependence.Scope>,
-                             _ context: FunctionPassContext)
-    -> SingleInlineArray<ScopeExtension> {
-
-    let enclosingScope = LifetimeDependence.Scope(base: borrowedValue, context)
-    if let extensions = enclosingScope.gatherExtensions(innerScopes: innerScopes, context) {
-      return extensions
+    // All owners must be arguments with exclusive access to depend on the caller's scope (inout_aliasable arguments do
+    // not have exclusivity).
+    var compatibleArgs = SingleInlineArray<FunctionArgument>()
+    for owner in owners {
+      guard let arg = owner as? FunctionArgument else {
+        return noCallerScope
+      }
+      guard arg.convention.isIndirectIn || arg.convention.isInout else {
+        return noCallerScope
+      }
+      compatibleArgs.push(arg)
     }
-    // This is the outermost scope to be extended because gatherExtensions did not find an enclosing scope.
-    return SingleInlineArray(element: getOuterExtension(owner: enclosingScope.parentValue, nestedScopes: innerScopes,
-                                                        context))
+    return compatibleArgs
   }
 }
 
@@ -460,121 +632,178 @@ extension ScopeExtension {
         return range.deinitialize()
       }
     }
+
+    var description: String {
+      switch self {
+      case .fullRange:
+        return "full range"
+      case let .addressRange(range):
+        return range.description
+      case let .valueRange(range):
+        return range.description
+      }
+    }
   }
 
   /// Return nil if the scope's owner is valid across the function, such as a guaranteed function argument.
-  func computeRange(_ localReachabilityCache: LocalVariableReachabilityCache, _ context: FunctionPassContext) -> Range?
-  {
+  func computeSingleOwnerRange(owner: Value) -> Range? {
     if owner.type.isAddress {
       // Get the range of the accessBase lifetime at the point where the outermost extendable scope begins.
-      if let range = AddressOwnershipLiveRange.compute(for: owner, at: nestedScopes.last!.extendableBegin!.instruction,
+      if let range = AddressOwnershipLiveRange.compute(for: owner, at: scopes.first!.firstInstruction,
                                                        localReachabilityCache, context) {
         return .addressRange(range)
       }
       return nil
     }
-    if owner.ownership == .owned {
+    switch owner.ownership {
+    case .owned:
       return .valueRange(computeLinearLiveness(for: owner, context))
+    case .guaranteed:
+      if let bbv = BeginBorrowValue(owner) {
+        if case .functionArgument = bbv {
+          return .fullRange
+        }
+        return .valueRange(computeLinearLiveness(for: bbv.value, context))
+      }
+      return nil
+    case .none:
+      return .fullRange
+    case .unowned:
+      return nil
     }
-    // Trivial or guaranted owner.
-    //
-    // TODO: limit extension to the begin_borrow [var_decl] scope
-    return .fullRange
-  }
-}
-
-/// Return an InstructionRange covering all the dependent uses of 'dependence'.
-private func computeDependentUseRange(of dependence: LifetimeDependence, within scopeExtension: inout ScopeExtension,
-                                      _ localReachabilityCache: LocalVariableReachabilityCache,
-                                      _ context: FunctionPassContext)
-  -> InstructionRange? {
-  let function = dependence.function
-  guard var ownershipRange = scopeExtension.computeRange(localReachabilityCache, context) else {
-    return nil
   }
-  defer {ownershipRange.deinitialize()}
 
-  // The innermost scope that must be extended must dominate all uses.
-  var useRange = InstructionRange(begin: scopeExtension.innerScope.extendableBegin!.instruction, context)
-  var walker = LifetimeDependentUseWalker(function, localReachabilityCache, context) {
-    // Do not extend the useRange past the ownershipRange.
-    let dependentInst = $0.instruction
-    if ownershipRange.coversUse(dependentInst) {
-      useRange.insert(dependentInst)
+  /// Return an InstructionRange covering all the dependent uses of 'dependence'.
+  ///
+  /// Initialize dependsOnCaller.
+  mutating func computeDependentUseRange(of dependence: LifetimeDependence) -> InstructionRange? {
+    if scopes.isEmpty {
+      return nil
     }
-    return .continueWalk
-  }
-  defer {walker.deinitialize()}
-
-  _ = walker.walkDown(dependence: dependence)
-
-  log("Scope fixup for dependent uses:\n\(useRange)")
-
-  scopeExtension.dependsOnCaller = walker.dependsOnCaller
+    let function = dependence.function
+    var inRangeUses = [Instruction]()
+    do {
+      // The innermost scope that must be extended must dominate all uses.
+      var walker = LifetimeDependentUseWalker(function, localReachabilityCache, context) {
+        inRangeUses.append($0.instruction)
+        return .continueWalk
+      }
+      defer {walker.deinitialize()}
+      // walkDown may abort if any utility used by address use walker, such asLocalVarUtils, has unhandled cases.
+      if walker.walkDown(dependence: dependence) == .abortWalk {
+        return nil
+      }
+      dependsOnCaller = walker.dependsOnCaller
+    }
+    for owner in owners {
+      guard var ownershipRange = computeSingleOwnerRange(owner: owner) else {
+        return nil
+      }
+      defer { ownershipRange.deinitialize() }
 
-  // Lifetime dependenent uses may not be dominated by the access. The dependent value may be used by a phi or stored
-  // into a memory location. The access may be conditional relative to such uses. If any use was not dominated, then
-  // `useRange` will include the function entry. There is not way to directly check
-  // useRange.isValid. useRange.blockRange.isValid is not a strong enough check because it will always succeed when
-  // useRange.begin == entryBlock even if a use if above useRange.begin.
-  let firstInst = function.entryBlock.instructions.first!
-  if firstInst != useRange.begin, useRange.contains(firstInst) {
-    useRange.deinitialize()
-    return nil
+      inRangeUses = inRangeUses.filter { ownershipRange.coversUse($0) }
+    }
+    var useRange = InstructionRange(begin: innermostScope.firstInstruction, context)
+    useRange.insert(contentsOf: inRangeUses)
+
+    log("Scope fixup for dependent uses:\n\(useRange)")
+
+    // Lifetime dependent uses may not be dominated by `innermostScope`. The dependent value may be used by a phi or
+    // stored into a memory location. The access may be conditional relative to such uses. If any use was not dominated,
+    // then `useRange` will include the function entry. There is no way to directly check if `useRange` is
+    // valid. `useRange.blockRange.isValid` is not a strong enough check because it will always succeed when
+    // `useRange.begin == entryBlock` even if a use is above `useRange.begin`. Instead check if `useRange` contains the
+    // first instruction, and the first instruction does not itself start `innermostScope`.
+    let firstInst = function.entryBlock.instructions.first!
+    if firstInst != useRange.begin, useRange.contains(firstInst) {
+      useRange.deinitialize()
+      return nil
+    }
+    return useRange
   }
-  return useRange
 }
 
-// Extend nested scopes across a use-range within their owner's range.
 extension ScopeExtension {
-  // Prepare to extend each scope.
-  func tryExtendScopes(over useRange: inout InstructionRange, _ context: some MutatingContext) -> Bool {
+  /// Return true if all nested scopes were extended across `useRange`. `useRange` has already been pruned to be a
+  /// subset of the ranges of the owners.
+  ///
+  /// Note: the scopes may not be strictly nested. Two adjacent scopes in the nested scopes array may have begin at the
+  /// same nesting level. Their begin instructions may occur in any order relative to the nested scopes array, but we
+  /// order the end instructions according to the arbitrary order that the scopes were inserted in the array. This is
+  /// conservative and could extend some scopes longer than strictly necessary. To improve this, `scopes` must be
+  /// represnted as a DAG by recording parent and child indices.
+  func canExtendScopes(over useRange: inout InstructionRange,
+                       scopesToExtend: inout SingleInlineArray<ExtendableScope>) -> Bool {
     var extendedUseRange = InstructionRange(begin: useRange.begin!, ends: useRange.ends, context)
-    // Insert the first instruction of the exit blocks to mimic 'useRange'. This is innacurate, but it produces the same
-    // result for canExtend() check below, which only checks reachability of end_apply.
+
+    // Insert the first instruction of the exit blocks to mimic `useRange`. There is no way to directly copy
+    // `useRange`. Inserting the exit block instructions is inaccurate, but for the purpose of canExtend() below, it has
+    // the same effect as a copy of `useRange`.
     extendedUseRange.insert(contentsOf: useRange.exits)
-    for innerScope in nestedScopes {
-      guard let beginInst = innerScope.extendableBegin else {
-        fatalError("all nested scopes must have a scoped begin instruction")
-      }
-      // Extend 'extendedUseRange' to to cover this scope's end instructions. The extended scope must at least cover the
-      // original scope because the original scope may protect other operations.
-      extendedUseRange.insert(contentsOf: beginInst.endInstructions)
-      if !innerScope.canExtend(over: &extendedUseRange, context) {
+    defer { extendedUseRange.deinitialize() }
+
+    // Append each scope that needs extension to scopesToExtend from the inner to the outer scope.
+    for extScope in scopes.reversed() {
+      var mustExtend = false
+      // Iterating over scopeEndInst ignores unreachable paths which may not include the dealloc_stack. This is fine
+      // because the stack allocation effectively covers the entire unreachable path.
+      for scopeEndInst in extScope.endInstructions {
+        switch extendedUseRange.overlaps(pathBegin: extScope.firstInstruction, pathEnd: scopeEndInst, context) {
+        case .containsPath, .containsEnd, .disjoint:
+          // containsPath can occur when the extendable scope has the same begin as the use range.
+          // disjoint is unexpected, but if it occurs then `extScope` must be before the useRange.
+          mustExtend = true
+          break
+        case .containsBegin, .overlappedByPath:
+          // containsBegin can occur when the extendable scope has the same begin as the use range.
+          //
+          // An outer scope might not originally cover one of its inner scopes. Therefore, extend 'extendedUseRange' to
+          // to cover this scope's end instructions. The extended scope must at least cover the original scopes because
+          // the original scopes may protect other operations.
+          extendedUseRange.insert(scopeEndInst)
+          break
+        }
+      }
+      if !mustExtend {
+        continue
+      }
+      scopesToExtend.push(extScope)
+      if !extScope.canExtend(over: &extendedUseRange, context) {
         // Scope ending instructions cannot be inserted at the 'range' boundary. Ignore all nested scopes.
         //
-        // Note: We could still extend previously prepared inner scopes up to this 'innerScope'. To do that, we would
-        // need to repeat the steps above: treat 'innerScope' as the new owner, and recompute 'useRange'. But this
+        // Note: We could still extend previously prepared inner scopes up to this scope. To do that, we would
+        // need to repeat the steps above: treat 'extScope' as the new owner, and recompute `useRange`. But this
         // scenario could only happen with nested coroutine, where the range boundary is reachable from the outer
         // coroutine's EndApply and AbortApply--it is vanishingly unlikely if not impossible.
         return false
       }
     }
-    extendedUseRange.deinitialize()
-    // extend(over:) must receive the original unmodified 'useRange'.
-    extend(over: &useRange, context)
     return true
   }
   
   // Extend the scopes that actually required extension.
   //
   // Consumes 'useRange'
-  private func extend(over useRange: inout InstructionRange, _ context: some MutatingContext) {
+  private mutating func extend(scopesToExtend: SingleInlineArray<ExtendableScope>,
+                               over useRange: inout InstructionRange,
+                               _ context: some MutatingContext) {
     var deadInsts = [Instruction]()
-    for innerScope in nestedScopes {
-      guard let beginInst = innerScope.extendableBegin else {
-        fatalError("all nested scopes must have a scoped begin instruction")
-      }
-      let mustExtend = beginInst.endInstructions.contains(where: { useRange.contains($0) })
-
+    for extScope in scopesToExtend {
       // Extend 'useRange' to to cover this scope's end instructions. 'useRange' cannot be extended until the
       // inner scopes have been extended.
-      for endInst in beginInst.endInstructions {
-        useRange.insert(endInst)
-      }
-      if mustExtend {
-        deadInsts += innerScope.extend(over: &useRange, context)
-      }
+      useRange.insert(contentsOf: extScope.endInstructions)
+
+      // Note, we could Skip extension here if we have a fully overlapping scope. But that requires computing the scope
+      // of [beginInst : beginInst.endInstructions) because an outer scope may be disjoint from the inner scope but
+      // still requires extension:
+      //     %access = begin_access [read] %owner       // <=== outer scoope
+      //     %temp = load [copy] %access
+      //     end_access %access
+      //     (%dependent, %token) = begin_apply (%temp) // <=== inner scope
+      //     end_apply %token
+      //
+      deadInsts += extScope.extend(over: &useRange, context)
+
       // Continue checking enclosing scopes for extension even if 'mustExtend' is false. Multiple ScopeExtensions may
       // share the same inner scope, so this inner scope may already have been extended while handling a previous
       // ScopeExtension. Nonetheless, some enclosing scopes may still require extension. This only happens when a
@@ -582,106 +811,155 @@ extension ScopeExtension {
     }
     // 'useRange' is invalid as soon as instructions are deleted.
     useRange.deinitialize()
+
     // Delete original end instructions.
     for deadInst in deadInsts {
+      if deadInst is DeallocStackInst {
+        mustFixStackNesting = true
+      }
       context.erase(instruction: deadInst)
     }
   }
 }
 
 // Extend a dependence scope to cover the dependent uses.
-private extension LifetimeDependence.Scope {
+extension ExtendableScope {
   /// Return true if new scope-ending instruction can be inserted at the range boundary.
   func canExtend(over range: inout InstructionRange, _ context: some Context) -> Bool {
-    switch self {
+    switch self.scope {
     case let .yield(yieldedValue):
-      let beginApply = yieldedValue.definingInstruction as! BeginApplyInst
-      let canEndAtBoundary = { (boundaryInst: Instruction) in
-        switch beginApply.endReaches(block: boundaryInst.parentBlock, context) {
-        case .abortReaches, .endReaches:
-          return true
-        case .none:
-          return false
-        }
-      }
-      for end in range.ends {
-        if (!canEndAtBoundary(end)) {
-          return false
-        }
-      }
-      for exit in range.exits {
-        if (!canEndAtBoundary(exit)) {
-          return false
-        }
+      return canExtend(beginApply: yieldedValue.definingInstruction as! BeginApplyInst, over: &range, context)
+    case let .initialized(initializer):
+      switch initializer {
+      case .argument, .yield:
+        // A yield is already considered nested within the coroutine.
+        return true
+      case .store:
+        return self.scope.allocStackInstruction != nil
       }
-      return true
     default:
       // non-yield scopes can always be ended at any point.
       return true
     }
   }
 
+  func canExtend(beginApply: BeginApplyInst, over range: inout InstructionRange, _ context: some Context) -> Bool {
+    let canEndAtBoundary = { (boundaryInst: Instruction) in
+      switch beginApply.endReaches(block: boundaryInst.parentBlock, context) {
+      case .abortReaches, .endReaches, .deadEndReaches:
+        return true
+      case .none:
+        return false
+      }
+    }
+    for end in range.ends {
+      if (!canEndAtBoundary(end)) {
+        return false
+      }
+    }
+    for exit in range.exits {
+      if (!canEndAtBoundary(exit)) {
+        return false
+      }
+    }
+    return true
+  }
+
   /// Extend this scope over the 'range' boundary. Return the old scope ending instructions to be deleted.
   func extend(over range: inout InstructionRange, _ context: some MutatingContext) -> [Instruction] {
-    guard let beginInst = extendableBegin else {
-      fatalError("all nested scoped must have a scoped begin instruction")
-    }
     // Collect the original end instructions and extend the range to to cover them. The resulting access scope
     // must cover the original scope because it may protect other memory operations.
-    var endInsts = [Instruction]()
-    for end in beginInst.endInstructions {
+    let originalScopeEnds = [Instruction](self.endInstructions)
+    // Track scope-ending instructions that have not yet been reused as range-ending instructions.
+    var unreusedEnds = InstructionSet(context)
+    for end in originalScopeEnds {
       assert(range.inclusiveRangeContains(end))
-      endInsts.append(end)
+      unreusedEnds.insert(end)
+    }
+    defer { unreusedEnds.deinitialize() }
+
+    // Never reuse dealloc_stack to avoid running data flow.
+    var endsToErase = [Instruction]()
+    if let deallocs = self.deallocs {
+      endsToErase.append(contentsOf: deallocs.map { $0 })
+      for dealloc in deallocs {
+        unreusedEnds.erase(dealloc)
+      }
     }
-    insertBoundaryEnds(range: &range, context)
-    return endInsts
-  }
 
-  /// Create new scope-ending instructions at the boundary of 'range'.
-  func insertBoundaryEnds(range: inout InstructionRange, _ context: some MutatingContext) {
     for end in range.ends {
-      let location = end.location.autoGenerated
-      if end is ReturnInst {
+      let location = end.location.asAutoGenerated
+      switch end {
+      case is BranchInst:
+        assert(end.parentBlock.singleSuccessor!.terminator is ReturnInst,
+               "a phi only ends a use range if it is a returned value")
+        fallthrough
+      case is ReturnInst:
         // End this inner scope just before the return. The mark_dependence base operand will be redirected to a
         // function argument.
         let builder = Builder(before: end, location: location, context)
         // Insert newEnd so that this scope will be nested in any outer scopes.
-        range.insert(createEndInstruction(builder, context))
+        range.insert(contentsOf: createEndInstructions(builder, context))
+        continue
+      default:
+        break
+      }
+      // If this range ending instruction was also scope-ending, then mark it as reused by removing it from the set.
+      if unreusedEnds.contains(end) {
+        unreusedEnds.erase(end)
+        assert(!unreusedEnds.contains(end))
         continue
       }
       Builder.insert(after: end, location: location, context) {
-        range.insert(createEndInstruction($0, context))
+        range.insert(contentsOf: createEndInstructions($0, context))
       }
     }
     for exitInst in range.exits {
-      let location = exitInst.location.autoGenerated
+      let location = exitInst.location.asAutoGenerated
       let builder = Builder(before: exitInst, location: location, context)
-      range.insert(createEndInstruction(builder, context))
+      range.insert(contentsOf: createEndInstructions(builder, context))
     }
+    endsToErase.append(contentsOf: originalScopeEnds.filter { unreusedEnds.contains($0) })
+    return endsToErase
   }
 
   /// Create a scope-ending instruction at 'builder's insertion point.
-  func createEndInstruction(_ builder: Builder, _ context: some Context) -> Instruction {
-    switch self {
+  func createEndInstructions(_ builder: Builder, _ context: some Context) -> SingleInlineArray<Instruction> {
+    switch self.scope {
     case let .access(beginAccess):
-      return builder.createEndAccess(beginAccess: beginAccess)
+      return SingleInlineArray(element: builder.createEndAccess(beginAccess: beginAccess))
     case let .borrowed(beginBorrow):
-      return builder.createEndBorrow(of: beginBorrow.value)
+      return SingleInlineArray(element: builder.createEndBorrow(of: beginBorrow.value))
     case let .yield(yieldedValue):
       let beginApply = yieldedValue.definingInstruction as! BeginApplyInst
       // createEnd() returns non-nil because beginApply.endReaches() was checked by canExtend()
-      return beginApply.createEnd(builder, context)!
+      return SingleInlineArray(element: beginApply.createEnd(builder, context)!)
     case let .initialized(initializer):
       switch initializer {
       case let .store(initializingStore: store, initialAddress: _):
+        var endInsts = SingleInlineArray<Instruction>()
         if let sb = store as? StoreBorrowInst {
-          return builder.createEndBorrow(of: sb)
+          endInsts.append(builder.createEndBorrow(of: sb))
+        }
+        if let allocStack = self.scope.allocStackInstruction {
+          endInsts.append(builder.createDeallocStack(allocStack))
+          return endInsts
         }
         break
       case .argument, .yield:
         // TODO: extend indirectly yielded scopes.
         break
       }
+    case let .owned(value):
+      return SingleInlineArray(element: builder.createDestroyValue(operand: value))
+    case let .local(varInst):
+      switch varInst {
+      case let .beginBorrow(beginBorrow):
+        // FIXME: we may need to rewrite the dealloc_stack.
+        return SingleInlineArray(element: builder.createEndBorrow(of: beginBorrow))
+      case let .moveValue(moveValue):
+        return SingleInlineArray(element: builder.createDestroyValue(operand: moveValue))
+      }
     default:
       break
     }
@@ -703,64 +981,62 @@ private extension BeginApplyInst {
       return builder.createEndApply(beginApply: self)
     case .abortReaches:
       return builder.createAbortApply(beginApply: self)
+    case .deadEndReaches:
+      return builder.createEndBorrow(of: self.token)
     }
   }
 
   enum EndReaches {
     case endReaches
     case abortReaches
+    case deadEndReaches
   }
 
   /// Return the single kind of coroutine termination that reaches 'reachableBlock' or nil.
   func endReaches(block reachableBlock: BasicBlock, _ context: some Context) -> EndReaches? {
-    var endBlocks = BasicBlockSet(context)
-    var abortBlocks = BasicBlockSet(context)
+    // TODO: use InlineArray<3> once bootstrapping is fixed.
+    var endingBlockMap: [(EndReaches, BasicBlockSet)] = [
+      (.endReaches, BasicBlockSet(context)),
+      (.abortReaches, BasicBlockSet(context)),
+      (.deadEndReaches, BasicBlockSet(context))
+    ]
     defer {
-      endBlocks.deinitialize()
-      abortBlocks.deinitialize()
+      for index in endingBlockMap.indices {
+        endingBlockMap[index].1.deinitialize()
+      }
     }
     for endInst in endInstructions {
+      let endKind: EndReaches
       switch endInst {
       case let endApply as EndApplyInst:
         // Cannot extend the scope of a coroutine when the resume produces a value.
         if !endApply.type.isEmpty(in: parentFunction) {
           return nil
         }
-        endBlocks.insert(endInst.parentBlock)
+        endKind = .endReaches
       case is AbortApplyInst:
-        abortBlocks.insert(endInst.parentBlock)
+        endKind = .abortReaches
+      case is EndBorrowInst:
+        endKind = .deadEndReaches
       default:
         fatalError("invalid begin_apply ending instruction")
       }
+      let endingBlocksIndex = endingBlockMap.firstIndex(where: { $0.0 == endKind })!
+      endingBlockMap[endingBlocksIndex].1.insert(endInst.parentBlock)
     }
     var endReaches: EndReaches?
     var backwardWalk = BasicBlockWorklist(context)
     defer { backwardWalk.deinitialize() }
 
     let backwardVisit = { (block: BasicBlock) -> WalkResult in
-      if endBlocks.contains(block) {
-        switch endReaches {
-        case .none:
-          endReaches = .endReaches
-          break
-        case .endReaches:
-          break
-        case .abortReaches:
-          return .abortWalk
+      for (endKind, endingBlocks) in endingBlockMap {
+        if endingBlocks.contains(block) {
+          if let endReaches = endReaches, endReaches != endKind {
+            return .abortWalk
+          }
+          endReaches = endKind
+          return .continueWalk
         }
-        return .continueWalk
-      }
-      if abortBlocks.contains(block) {
-        switch endReaches {
-        case .none:
-          endReaches = .abortReaches
-          break
-        case .abortReaches:
-          break
-        case .endReaches:
-          return .abortWalk
-        }
-        return .continueWalk
       }
       if block == self.parentBlock {
         // the insertion point is not dominated by the coroutine
@@ -850,7 +1126,7 @@ private struct LifetimeDependentUseWalker : LifetimeDependenceDefUseWalker {
   }
 
   mutating func yieldedDependence(result: Operand) -> WalkResult {
-    return .continueWalk
+    return visitor(result)
   }
 
   mutating func storeToYieldDependence(address: Value, of operand: Operand) -> WalkResult {
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LoopInvariantCodeMotion.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LoopInvariantCodeMotion.swift
new file mode 100644
index 0000000000000..ee4d03629e8c3
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LoopInvariantCodeMotion.swift
@@ -0,0 +1,1284 @@
+//===--- LoopInvariantCodeMotion.swift ------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+
+/// Hoist loop invariant code out of innermost loops.
+let loopInvariantCodeMotionPass = FunctionPass(name: "loop-invariant-code-motion") { function, context in
+  for loop in context.loopTree.loops {
+    optimizeTopLevelLoop(topLevelLoop: loop, context)
+  }
+  
+  if context.needFixStackNesting {
+    context.fixStackNesting(in: function)
+  }
+}
+
+private func optimizeTopLevelLoop(topLevelLoop: Loop, _ context: FunctionPassContext) {
+  var innerLoops = Stack<Loop>(context)
+  defer { innerLoops.deinitialize() }
+  
+  getWorkList(forLoop: topLevelLoop, workList: &innerLoops)
+
+  while let thisLoop = innerLoops.pop() {
+    // We only support Loops with a preheader.
+    guard thisLoop.preheader != nil else {
+      continue
+    }
+    
+    var thisLoopChanged = false
+
+    repeat {
+      var movableInstructions = analyzeLoopAndSplitLoads(loop: thisLoop, context)
+      thisLoopChanged = optimizeLoop(loop: thisLoop, movableInstructions: &movableInstructions, context)
+    } while thisLoopChanged
+  }
+}
+
+/// Creates post-order DFS work list of inner loops.
+private func getWorkList(forLoop loop: Loop, workList: inout Stack<Loop>) {
+  workList.push(loop)
+  
+  for innerLoop in loop.innerLoops {
+    getWorkList(forLoop: innerLoop, workList: &workList)
+  }
+}
+
+/// Instructions that can be moved outside the loop.
+private struct MovableInstructions {
+  var loadAndStoreAccessPaths: [AccessPath] = []
+  
+  var speculativelyHoistable: [Instruction] = []
+  var loadsAndStores: [Instruction] = []
+  var hoistUp: [Instruction] = []
+  var sinkDown: [Instruction] = []
+  var scopedInsts: [ScopedInstruction] = []
+}
+
+/// Analyzed instructions inside the currently processed loop.
+private struct AnalyzedInstructions {
+  /// Side effects of the loop.
+  var loopSideEffects: StackWithCount<Instruction>
+  
+  private var blockSideEffectBottomMarker: StackWithCount<Instruction>.Marker
+  
+  /// Side effects of the currently analyzed block.
+  var sideEffectsOfCurrentBlock: StackWithCount<Instruction>.Segment {
+    return StackWithCount<Instruction>.Segment(
+      in: loopSideEffects,
+      low: blockSideEffectBottomMarker,
+      high: loopSideEffects.top
+    )
+  }
+  
+  /// Contains either:
+  /// * an apply to the addressor of the global
+  /// * a builtin "once" of the global initializer
+  var globalInitCalls: Stack<Instruction>
+  var readOnlyApplies: Stack<FullApplySite>
+  var loads: Stack<LoadInst>
+  var stores: Stack<StoreInst>
+  var scopedInsts: Stack<UnaryInstruction>
+  var fullApplies: Stack<FullApplySite>
+  
+  /// `true` if the loop has instructions which (may) read from memory, which are not in `Loads` and not in `sideEffects`.
+  var hasOtherMemReadingInsts = false
+  
+  /// `true` if one of the side effects might release.
+  lazy var sideEffectsMayRelease = loopSideEffects.contains(where: { $0.mayRelease })
+  
+  init (_ context: FunctionPassContext) {
+    self.loopSideEffects = StackWithCount<Instruction>(context)
+    self.blockSideEffectBottomMarker = loopSideEffects.top
+    
+    self.globalInitCalls = Stack<Instruction>(context)
+    self.readOnlyApplies = Stack<FullApplySite>(context)
+    self.loads = Stack<LoadInst>(context)
+    self.stores = Stack<StoreInst>(context)
+    self.scopedInsts = Stack<UnaryInstruction>(context)
+    self.fullApplies = Stack<FullApplySite>(context)
+  }
+  
+  mutating func deinitialize() {
+    readOnlyApplies.deinitialize()
+    globalInitCalls.deinitialize()
+    loopSideEffects.deinitialize()
+    loads.deinitialize()
+    stores.deinitialize()
+    scopedInsts.deinitialize()
+    fullApplies.deinitialize()
+  }
+  
+  /// Mark the start of currently processed block side effects.
+  mutating func markBeginOfBlock() {
+    blockSideEffectBottomMarker = loopSideEffects.top
+  }
+}
+
+/// Analyzes `loop` for hosting/sinking potential.
+/// Computes `MovableInstructions` we may be able to move out of the loop
+///
+/// This may split some loads into smaller loads.
+private func analyzeLoopAndSplitLoads(loop: Loop, _ context: FunctionPassContext) -> MovableInstructions {
+  // TODO: Remove once uses lowered OSSA.
+  loop.splitCriticalExitingAndBackEdges(context)
+
+  var movableInstructions = MovableInstructions()
+  var analyzedInstructions = AnalyzedInstructions(context)
+  defer { analyzedInstructions.deinitialize() }
+
+  analyzeInstructions(in: loop, &analyzedInstructions, &movableInstructions, context)
+
+  collectHoistableGlobalInitCalls(in: loop, analyzedInstructions, &movableInstructions, context)
+
+  collectProjectableAccessPathsAndSplitLoads(in: loop, &analyzedInstructions, &movableInstructions, context)
+  
+  collectMovableInstructions(in: loop, &analyzedInstructions, &movableInstructions, context)
+    
+  return movableInstructions
+}
+
+/// Analyze instructions inside the `loop`. Compute side effects and populate `analyzedInstructions`.
+///
+/// - note: Ideally, `movableInstructions` should be fully computed in `collectMovableInstructions`.
+private func analyzeInstructions(
+  in loop: Loop,
+  _ analyzedInstructions: inout AnalyzedInstructions,
+  _ movableInstructions: inout MovableInstructions,
+  _ context: FunctionPassContext
+) {
+  for bb in loop.loopBlocks {
+    analyzedInstructions.markBeginOfBlock()
+    
+    for inst in bb.instructions {
+      switch inst {
+      case is FixLifetimeInst:
+        break // We can ignore the side effects of FixLifetimes
+      case let loadInst as LoadInst:
+        analyzedInstructions.loads.append(loadInst)
+      case let uncheckedOwnershipConversionInst as UncheckedOwnershipConversionInst:
+        analyzedInstructions.analyzeSideEffects(ofInst: uncheckedOwnershipConversionInst)
+      case let storeInst as StoreInst:
+        analyzedInstructions.stores.append(storeInst)
+        analyzedInstructions.analyzeSideEffects(ofInst: storeInst)
+      case let beginAccessInst as BeginAccessInst:
+        analyzedInstructions.scopedInsts.append(beginAccessInst)
+        analyzedInstructions.analyzeSideEffects(ofInst: beginAccessInst)
+      case let beginBorrowInst as BeginBorrowInstruction:
+        analyzedInstructions.analyzeSideEffects(ofInst: beginBorrowInst)
+      case let refElementAddrInst as RefElementAddrInst:
+        movableInstructions.speculativelyHoistable.append(refElementAddrInst)
+      case let condFailInst as CondFailInst:
+        analyzedInstructions.analyzeSideEffects(ofInst: condFailInst)
+      case let fullApply as FullApplySite:
+        if fullApply.isSafeReadOnlyApply(context.calleeAnalysis) {
+          analyzedInstructions.readOnlyApplies.append(fullApply)
+        } else if let callee = fullApply.referencedFunction,
+                  callee.isGlobalInitFunction, // Calls to global inits are different because we don't care about side effects which are "after" the call in the loop.
+                  !fullApply.globalInitMayConflictWith(
+                    blockSideEffectSegment: analyzedInstructions.sideEffectsOfCurrentBlock,
+                    context.aliasAnalysis
+                  ) {
+          // Check against side-effects within the same block.
+          // Side-effects in other blocks are checked later (after we
+          // scanned all blocks of the loop) in `collectHoistableGlobalInitCalls`.
+          analyzedInstructions.globalInitCalls.append(fullApply)
+        }
+        
+        analyzedInstructions.fullApplies.append(fullApply)
+        
+        // Check for array semantics and side effects - same as default
+        fallthrough
+      default:
+        switch inst {
+        case let builtinInst as BuiltinInst:
+          switch builtinInst.id {
+          case .Once, .OnceWithContext:
+            if !builtinInst.globalInitMayConflictWith(
+              blockSideEffectSegment: analyzedInstructions.sideEffectsOfCurrentBlock,
+              context.aliasAnalysis
+            ) {
+              analyzedInstructions.globalInitCalls.append(builtinInst)
+            }
+          default: break
+          }
+        default: break
+        }
+        
+        analyzedInstructions.analyzeSideEffects(ofInst: inst)
+        
+        if inst.canBeHoisted(outOf: loop, context) {
+          movableInstructions.hoistUp.append(inst)
+        }
+      }
+    }
+  }
+}
+
+/// Process collected global init calls. Moves them to `hoistUp` if they don't conflict with any side effects.
+private func collectHoistableGlobalInitCalls(
+  in loop: Loop,
+  _ analyzedInstructions: AnalyzedInstructions,
+  _ movableInstructions: inout MovableInstructions,
+  _ context: FunctionPassContext
+) {
+  for globalInitCall in analyzedInstructions.globalInitCalls {
+    // Check against side effects which are "before" (i.e. post-dominated by) the global initializer call.
+    //
+    // The effects in the same block have already been checked before
+    // adding this global init call to `analyzedInstructions.globalInitCalls` in `analyzeInstructions`.
+    if globalInitCall.parentBlock.postDominates(loop.preheader!, context.postDominatorTree),
+       !globalInitCall.globalInitMayConflictWith(
+         loopSideEffects: analyzedInstructions.loopSideEffects,
+         context.aliasAnalysis,
+         context.postDominatorTree
+       ) {
+      movableInstructions.hoistUp.append(globalInitCall)
+    }
+  }
+}
+
+/// Collect memory locations for which we can move all loads and stores out of the loop.
+/// `loads` may mutate during this loop.
+private func collectProjectableAccessPathsAndSplitLoads(
+  in loop: Loop,
+  _ analyzedInstructions: inout AnalyzedInstructions,
+  _ movableInstructions: inout MovableInstructions,
+  _ context: FunctionPassContext
+) {
+  if !analyzedInstructions.hasOtherMemReadingInsts {
+    for storeInst in analyzedInstructions.stores {
+      let accessPath = storeInst.destination.accessPath
+      if accessPath.isLoopInvariant(loop: loop),
+         analyzedInstructions.isOnlyLoadedAndStored(
+           accessPath: accessPath,
+           storeAddr: storeInst.destination,
+           context.aliasAnalysis
+         ),
+         !movableInstructions.loadAndStoreAccessPaths.contains(accessPath),
+         // This is not a requirement for functional correctness, but we don't want to
+         // _speculatively_ load and store the value (outside of the loop).
+         analyzedInstructions.storesCommonlyDominateExits(of: loop, storingTo: accessPath, context),
+         analyzedInstructions.splitLoads(
+           storeAddr: storeInst.destination,
+           accessPath: accessPath,
+           context
+         ) {
+        movableInstructions.loadAndStoreAccessPaths.append(accessPath)
+      }
+    }
+  }
+}
+
+/// Computes movable instructions using computed analyzed instructions.
+private func collectMovableInstructions(
+  in loop: Loop,
+  _ analyzedInstructions: inout AnalyzedInstructions,
+  _ movableInstructions: inout MovableInstructions,
+  _ context: FunctionPassContext
+) {
+  var loadInstCounter = 0
+  var readOnlyApplyCounter = 0
+  for bb in loop.loopBlocks {
+    for inst in bb.instructions {
+      switch inst {
+      case let fixLifetimeInst as FixLifetimeInst:
+        guard fixLifetimeInst.parentBlock.dominates(loop.preheader!, context.dominatorTree) else {
+          continue
+        }
+        
+        if !analyzedInstructions.sideEffectsMayRelease || !analyzedInstructions.loopSideEffectsMayWriteTo(address: fixLifetimeInst.operand.value, context.aliasAnalysis) {
+          movableInstructions.sinkDown.append(fixLifetimeInst)
+        }
+      case let loadInst as LoadInst:
+        // Avoid quadratic complexity in corner cases. Usually, this limit will not be exceeded.
+        if loadInstCounter * analyzedInstructions.loopSideEffects.count < 8000,
+           !analyzedInstructions.loopSideEffectsMayWriteTo(address: loadInst.operand.value, context.aliasAnalysis) {
+          movableInstructions.hoistUp.append(loadInst)
+        }
+        
+        loadInstCounter += 1
+        
+        movableInstructions.loadsAndStores.append(loadInst)
+      case is UncheckedOwnershipConversionInst:
+        break // TODO: Add support
+      case let storeInst as StoreInst:
+        switch storeInst.storeOwnership {
+        case .assign:
+          continue  // TODO: Add support
+        case .unqualified, .trivial, .initialize:
+          break
+        }
+        movableInstructions.loadsAndStores.append(storeInst)
+      case let condFailInst as CondFailInst:
+        // We can (and must) hoist cond_fail instructions if the operand is
+        // invariant. We must hoist them so that we preserve memory safety. A
+        // cond_fail that would have protected (executed before) a memory access
+        // must - after hoisting - also be executed before said access.
+        movableInstructions.hoistUp.append(condFailInst)
+      case let beginAccessInst as BeginAccessInst:
+        if beginAccessInst.canScopedInstructionBeHoisted(outOf: loop, analyzedInstructions: analyzedInstructions, context) {
+          movableInstructions.scopedInsts.append(beginAccessInst)
+        }
+      case let beginBorrowInst as BeginBorrowInstruction:
+        if !beginBorrowInst.isLexical && beginBorrowInst.canScopedInstructionBeHoisted(outOf: loop, analyzedInstructions: analyzedInstructions, context) {
+          movableInstructions.scopedInsts.append(beginBorrowInst)
+        }
+      case let fullApplySite as FullApplySite:
+        guard analyzedInstructions.readOnlyApplies.contains(where: { $0 == fullApplySite }) else {
+          break
+        }
+        
+        // Avoid quadratic complexity in corner cases. Usually, this limit will not be exceeded.
+        if readOnlyApplyCounter * analyzedInstructions.loopSideEffects.count < 8000,
+           fullApplySite.isSafeReadOnlyApply(
+             for: analyzedInstructions.loopSideEffects,
+             context.aliasAnalysis,
+             context.calleeAnalysis
+           ) {
+          if let beginApplyInst = fullApplySite as? BeginApplyInst {
+            movableInstructions.scopedInsts.append(beginApplyInst)
+          } else {
+            movableInstructions.hoistUp.append(fullApplySite)
+          }
+          
+          readOnlyApplyCounter += 1
+        }
+      default:
+        break
+      }
+    }
+  }
+}
+
+/// Optimizes the loop by performing in following order:
+/// - speculative hoist
+/// - projection, hoist and sink of loads and stores
+/// - hoist of instructions that are guaranteed to be executed
+/// - sink
+/// - hoist with sink of scoped instructions
+private func optimizeLoop(
+  loop: Loop,
+  movableInstructions: inout MovableInstructions,
+  _ context: FunctionPassContext
+) -> Bool {
+  var changed = false
+  
+  // TODO: If we hoist tuple_element_addr and struct_element_addr instructions here, hoistAndSinkLoadsAndStores could converge after just one execution!
+  changed = movableInstructions.speculativelyHoistInstructions(outOf: loop, context)  || changed
+  changed = movableInstructions.hoistAndSinkLoadsAndStores(outOf: loop, context)      || changed
+  changed = movableInstructions.hoistInstructions(outOf: loop, context)               || changed
+  changed = movableInstructions.sinkInstructions(outOf: loop, context)                || changed
+  changed = movableInstructions.hoistWithSinkScopedInstructions(outOf: loop, context) || changed
+
+  return changed
+}
+
+extension BasicBlock {
+  func containsStoresTo(accessPath: AccessPath) -> Bool {
+    return instructions.contains { inst in
+      return inst.operands.contains { operand in
+        if let storeInst = operand.instruction as? StoreInst,
+           storeInst.destination.accessPath == accessPath {
+          return true
+        } else {
+          return false
+        }
+      }
+    }
+  }
+}
+
+private extension AnalyzedInstructions {
+  /// Adds side effects of `inst` to the analyzed instructions.
+  mutating func analyzeSideEffects(ofInst inst: Instruction) {
+    if inst.mayHaveSideEffects {
+      loopSideEffects.append(inst)
+    } else if inst.mayReadFromMemory {
+      hasOtherMemReadingInsts = true
+    }
+  }
+  
+  /// Returns true if all instructions in `sideEffects` which may alias with
+  /// this path are either loads or stores from this path.
+  ///
+  /// `storeAddr` is only needed for AliasAnalysis until we have an interface
+  /// that supports `AccessPath`.
+  func isOnlyLoadedAndStored(
+    accessPath: AccessPath,
+    storeAddr: Value,
+    _ aliasAnalysis: AliasAnalysis
+  ) -> Bool {
+    if (loopSideEffects.contains { sideEffect in
+      switch sideEffect {
+      case let storeInst as StoreInst:
+        if storeInst.storesTo(accessPath) {
+          return false
+        }
+      case let loadInst as LoadInst:
+        if loadInst.loadsFrom(accessPath) {
+          return false
+        }
+      default: break
+      }
+      
+      // Pass the original address value until we can fix alias analysis.
+      return sideEffect.mayReadOrWrite(address: storeAddr, aliasAnalysis)
+    }) {
+      return false
+    }
+        
+    if (loads.contains { loadInst in
+      loadInst.mayRead(fromAddress: storeAddr, aliasAnalysis) && !loadInst.overlaps(accessPath: accessPath)
+    }) {
+      return false
+    }
+          
+    if (stores.contains { storeInst in
+      storeInst.mayWrite(toAddress: storeAddr, aliasAnalysis) && !storeInst.storesTo(accessPath)
+    }) {
+      return false
+    }
+    
+    return true
+  }
+  
+  /// Returns `true` if all stores to `accessPath` commonly dominate the loop exits.
+  func storesCommonlyDominateExits(of loop: Loop, storingTo accessPath: AccessPath, _ context: FunctionPassContext) -> Bool {
+    var exitingBlocksSet = BasicBlockSet(context)
+    var storeBlocks = BasicBlockSet(context)
+    var worklist = BasicBlockWorklist(context)
+    defer {
+      exitingBlocksSet.deinitialize()
+      storeBlocks.deinitialize()
+      worklist.deinitialize()
+    }
+    
+    // Also a store in the pre-header dominates all exists. Although the situation
+    // is a bit different here: the store in the pre-header remains - it's not
+    // (re)moved by the LICM transformation.
+    // But even if the loop-stores are not dominating the loop exits, it
+    // makes sense to move them out of the loop if this case. When this is done,
+    // dead-store-elimination can then most likely eliminate the store in the
+    // pre-header.
+    //
+    //   pre_header:
+    //     store %v1 to %addr
+    //   header:
+    //     cond_br %cond, then, tail
+    //   then:
+    //     store %v2 to %addr    // a conditional store in the loop
+    //     br tail
+    //   tail:
+    //     cond_br %loop_cond, header, exit
+    //   exit:
+    //
+    //  will be transformed to
+    //
+    //   pre_header:
+    //     store %v1 to %addr    // <- can be removed by DSE afterwards
+    //   header:
+    //     cond_br %cond, then, tail
+    //   then:
+    //     br tail
+    //   tail(%phi):
+    //     cond_br %loop_cond, header, exit
+    //   exit:
+    //     store %phi to %addr
+    //
+    if loop.preheader!.containsStoresTo(accessPath: accessPath) {
+      return true
+    }
+    
+    // Create a set of exiting blocks for efficient lookup later.
+    exitingBlocksSet.insert(contentsOf: loop.exitingBlocks)
+    
+    // Collect as many recognizable store parent blocks as possible. It's ok if not all stores are collected.
+    storeBlocks.insert(contentsOf: stores
+      .filter({ $0.destination.accessPath == accessPath })
+      .map(\.parentBlock))
+    
+    // If a store is in the loop header, we already know that it's dominating all loop exits.
+    if storeBlocks.contains(loop.header) {
+      return true
+    }
+    
+    // Starting from the header, check whether all stores are alive.
+    worklist.pushIfNotVisited(loop.header)
+    while let block = worklist.pop() {
+      if storeBlocks.contains(block) {
+        continue
+      }
+      
+      if exitingBlocksSet.contains(block),
+         block.successors.filter({ $0.terminator is UnreachableInst }).count != block.successors.count {
+        return false
+      }
+      
+      worklist.pushIfNotVisited(contentsOf: block.successors)
+    }
+    
+    return true
+  }
+  
+  /// Returns true if `loopSideEffects` contains any memory writes which
+  /// may alias with the memory `address`.
+  func loopSideEffectsMayWriteTo(address: Value, _ aliasAnalysis: AliasAnalysis) -> Bool {
+    return loopSideEffects
+      .contains { sideEffect in
+        sideEffect.mayWrite(toAddress: address, aliasAnalysis)
+      }
+  }
+  
+  /// Find all loads that contain `accessPath`. Split them into a load with
+  /// identical `accessPath` and a set of non-overlapping loads. Add the new
+  /// non-overlapping loads to `loads`.
+  mutating func splitLoads(
+    storeAddr: Value,
+    accessPath: AccessPath,
+    _ context: FunctionPassContext
+  ) -> Bool {
+    var newLoads = Stack<LoadInst>(context)
+    defer {
+      loads.append(contentsOf: newLoads)
+      newLoads.deinitialize()
+    }
+    var splitCounter = 0
+
+    while let loadInst = loads.pop() {
+      // Found a load wider than the store to accessPath.
+      //
+      // SplitLoads is called for each unique access path in the loop that is
+      // only loaded from and stored to and this loop takes time proportional to:
+      //   num-wide-loads x num-fields x num-loop-memops
+      //
+      // For each load wider than the store, it creates a new load for each field
+      // in that type. Each new load is inserted in the LoadsAndStores vector.  To
+      // avoid super-linear behavior for large types (e.g. giant tuples), limit
+      // growth of new loads to an arbitrary constant factor per access path.
+      guard splitCounter <= 6 else {
+        newLoads.push(loadInst)
+        return false
+      }
+
+      guard !loadInst.isDeleted, loadInst.operand.value.accessPath.contains(accessPath) else {
+        newLoads.push(loadInst)
+        continue
+      }
+
+      guard let projectionPath =  loadInst.operand.value.accessPath.getProjection(to: accessPath),
+            let splitLoads = loadInst.trySplit(alongPath: projectionPath, context) else {
+        newLoads.push(loadInst)
+        return false
+      }
+      
+      splitCounter += splitLoads.count
+      newLoads.append(contentsOf: splitLoads)
+    }
+
+    return true
+  }
+}
+
+private extension MovableInstructions {
+  /// Hoist instructions speculatively.
+  ///
+  /// Contrary to `hoistInstructions`, it doesn't only go through instructions in blocks that dominate all exits.
+  mutating func speculativelyHoistInstructions(outOf loop: Loop, _ context: FunctionPassContext) -> Bool {
+    var changed = false
+    
+    for inst in speculativelyHoistable {
+      changed = inst.hoist(outOf: loop, context) || changed
+    }
+    
+    return changed
+  }
+  
+  /// Hoists and sinks loads with matching stores. Projects loads.
+  mutating func hoistAndSinkLoadsAndStores(outOf loop: Loop, _ context: FunctionPassContext) -> Bool {
+    var changed = false
+    
+    for accessPath in loadAndStoreAccessPaths {
+      changed = hoistAndSinkLoadAndStore(outOf: loop, accessPath: accessPath, context: context) || changed
+    }
+    
+    return changed
+  }
+
+  /// Only hoists instructions in blocks that dominate all exit and latch blocks.
+  /// It doesn't hoist instructions speculatively.
+  mutating func hoistInstructions(outOf loop: Loop, _ context: FunctionPassContext) -> Bool {
+    let dominatingBlocks = loop.getBlocksThatDominateAllExitingAndLatchBlocks(context)
+    var changed = false
+
+    for bb in dominatingBlocks {
+      for inst in bb.instructions where hoistUp.contains(inst) {
+        changed = inst.hoist(outOf: loop, context) || changed
+      }
+    }
+
+    return changed
+  }
+
+  /// Sink instructions.
+  mutating func sinkInstructions(outOf loop: Loop, _ context: FunctionPassContext) -> Bool {
+    let dominatingBlocks = loop.getBlocksThatDominateAllExitingAndLatchBlocks(context)
+    var changed = false
+
+    for inst in sinkDown where dominatingBlocks.contains(inst.parentBlock) {
+      changed = inst.sink(outOf: loop, context) || changed
+    }
+
+    return changed
+  }
+
+  /// Hoist and sink scoped instructions.
+  mutating func hoistWithSinkScopedInstructions(outOf loop: Loop, _ context: FunctionPassContext) -> Bool {
+    // Since we don't sink scoped instructions to dead exit blocks, we need to check there's
+    // at least one exit block to which we can sink end instructions. Otherwise we could end up
+    // with partially hoisted scoped instruction that could lead to e.g. value overconsumption.
+    guard !loop.hasNoExitBlocks, loop.exitBlocks.contains(where: { !context.deadEndBlocks.isDeadEnd($0) }) else {
+      return false
+    }
+    
+    var changed = false
+
+    for scopedInst in scopedInsts {
+      if let storeBorrowInst = scopedInst as? StoreBorrowInst {
+        _ = storeBorrowInst.allocStack.hoist(outOf: loop, context)
+        
+        var sankFirst = false
+        for deallocStack in storeBorrowInst.allocStack.deallocations {
+          if sankFirst {
+            context.erase(instruction: deallocStack)
+          } else {
+            sankFirst = deallocStack.sink(outOf: loop, context)
+          }
+        }
+        
+        context.notifyInvalidatedStackNesting()
+      }
+
+      guard scopedInst.hoist(outOf: loop, context) else {
+        continue
+      }
+
+      // We only want to sink the first end_access and erase the rest to not introduce duplicates.
+      var sankFirst = false
+      for endAccess in scopedInst.endInstructions {
+        if sankFirst {
+          context.erase(instruction: endAccess)
+        } else {
+          sankFirst = endAccess.sink(outOf: loop, context)
+        }
+      }
+      
+      changed = true
+    }
+
+    return changed
+  }
+
+  private mutating func hoistAndSinkLoadAndStore(
+    outOf loop: Loop,
+    accessPath: AccessPath,
+    context: FunctionPassContext
+  ) -> Bool {
+
+    // If the memory is not initialized at all exits, it would be wrong to insert stores at exit blocks.
+    guard memoryIsInitializedAtAllExits(of: loop, accessPath: accessPath, context) else {
+      return false
+    }
+
+    // Initially load the value in the loop pre header.
+    let builder = Builder(before: loop.preheader!.terminator, context)
+    var firstStore: StoreInst?
+    
+    // If there are multiple stores in a block, only the last one counts.
+    for case let storeInst as StoreInst in loadsAndStores where storeInst.storesTo(accessPath) {
+      // If a store just stores the loaded value, bail. The operand (= the load)
+      // will be removed later, so it cannot be used as available value.
+      // This corner case is surprisingly hard to handle, so we just give up.
+      if let srcLoadInst = storeInst.source as? LoadInst,
+         srcLoadInst.loadsFrom(accessPath) {
+        return false
+      }
+      
+      if firstStore == nil {
+        firstStore = storeInst
+      } else if storeInst.destination.type != firstStore!.destination.type {
+        // This transformation assumes that the values of all stores in the loop
+        // must be interchangeable. It won't work if stores different types
+        // because of casting or payload extraction even though they have the
+        // same access path.
+        return false
+      }
+    }
+    
+    guard let firstStore else {
+      return false
+    }
+
+    // We currently don't support split `load [take]`, i.e. `load [take]` which does _not_ load all
+    // non-trivial fields of the initial value.
+    for case let load as LoadInst in loadsAndStores {
+      if load.loadOwnership == .take,
+         let path = accessPath.getProjection(to: load.address.accessPath),
+         !firstStore.destination.type.isProjectingEntireNonTrivialMembers(path: path, in: load.parentFunction)
+      {
+        return false
+      }
+    }
+
+    var ssaUpdater = SSAUpdater(
+      function: firstStore.parentFunction,
+      type: firstStore.destination.type.objectType,
+      ownership: firstStore.source.ownership,
+      context
+    )
+    
+    // Set all stored values as available values in the ssaUpdater.
+    for case let storeInst as StoreInst in loadsAndStores where storeInst.storesTo(accessPath) {
+      ssaUpdater.addAvailableValue(storeInst.source, in: storeInst.parentBlock)
+    }
+    
+    var cloner = Cloner(cloneBefore: loop.preheader!.terminator, context)
+    defer { cloner.deinitialize() }
+    
+    guard let initialAddr = (cloner.cloneRecursively(value: firstStore.destination) { srcAddr, cloner in
+      switch srcAddr {
+      case is AllocStackInst, is BeginBorrowInst, is MarkDependenceInst:
+        return .stopCloning
+      default: break
+      }
+      
+      // Clone projections until the address dominates preheader.
+      if srcAddr.parentBlock.dominates(loop.preheader!, context.dominatorTree) {
+        cloner.recordFoldedValue(srcAddr, mappedTo: srcAddr)
+        return .customValue(srcAddr)
+      } else {
+        // Return nil invalid to continue cloning.
+        return .defaultValue
+      }
+    }) else {
+      return false
+    }
+    
+    let ownership: LoadInst.LoadOwnership = firstStore.parentFunction.hasOwnership ? (firstStore.storeOwnership == .initialize ? .take : .trivial) : .unqualified
+    
+    let initialLoad = builder.createLoad(fromAddress: initialAddr, ownership: ownership)
+    ssaUpdater.addAvailableValue(initialLoad, in: loop.preheader!)
+    
+    var changed = false
+    var currentBlock: BasicBlock?
+    var currentVal: Value?
+    
+    // Remove all stores and replace the loads with the current value.
+    //
+    // This loop depends on loadsAndStores being in order the instructions appear in blocks.
+    for inst in loadsAndStores {
+      let block = inst.parentBlock
+      
+      if block != currentBlock {
+        currentBlock = block
+        currentVal = nil
+      }
+      
+      if let storeInst = inst as? StoreInst, storeInst.storesTo(accessPath) {
+        currentVal = storeInst.source
+        context.erase(instruction: storeInst)
+        changed = true
+        continue
+      }
+      
+      guard let loadInst = inst as? LoadInst,
+            loadInst.loadsFrom(accessPath) else {
+        continue
+      }
+      
+      // If we didn't see a store in this block yet, get the current value from the ssaUpdater.
+      let rootVal = currentVal ?? ssaUpdater.getValue(inMiddleOf: block)
+      
+      if loadInst.operand.value.accessPath == accessPath {
+        if loadInst.loadOwnership == .copy {
+          let builder = Builder(before: loadInst, context)
+          let copy = builder.createCopyValue(operand: rootVal)
+          loadInst.replace(with: copy, context)
+        } else {
+          loadInst.replace(with: rootVal, context)
+        }
+        changed = true
+        continue
+      }
+      
+      guard let projectionPath = accessPath.getProjection(to: loadInst.operand.value.accessPath) else {
+        continue
+      }
+    
+      let builder = Builder(before: loadInst, context)
+      let projection = if loadInst.loadOwnership == .copy {
+        rootVal.createProjectionAndCopy(path: projectionPath, builder: builder)
+      } else {
+        rootVal.createProjection(path: projectionPath, builder: builder)
+      }
+      loadInst.replace(with: projection, context)
+      
+      changed = true
+    }
+    
+    loadsAndStores.removeAll(where: { $0.isDeleted })
+    
+    // Store back the value at all loop exits.
+    for exitBlock in loop.exitBlocks {
+      assert(exitBlock.hasSinglePredecessor, "Exiting edge should not be critical.")
+      
+      let builder = Builder(before: exitBlock.instructions.first!, context)
+      
+      builder.createStore(
+        source: ssaUpdater.getValue(inMiddleOf: exitBlock),
+        destination: initialAddr,
+        ownership: firstStore.storeOwnership
+      )
+      changed = true
+    }
+    
+    // In case the value is only stored but never loaded in the loop.
+    if initialLoad.uses.isEmpty {
+      context.erase(instruction: initialLoad)
+    }
+    
+    return changed
+  }
+
+  func memoryIsInitializedAtAllExits(of loop: Loop, accessPath: AccessPath, _ context: FunctionPassContext) -> Bool {
+
+    // Perform a simple dataflow analysis which checks if there is a path from a `load [take]`
+    // (= the only kind of instruction which can de-initialize the memory) to a loop exit without
+    // a `store` in between.
+
+    var stores = InstructionSet(context)
+    defer { stores.deinitialize() }
+    for case let store as StoreInst in loadsAndStores where store.storesTo(accessPath) {
+      stores.insert(store)
+    }
+
+    var exitInsts = InstructionSet(context)
+    defer { exitInsts.deinitialize() }
+    exitInsts.insert(contentsOf: loop.exitBlocks.lazy.map { $0.instructions.first! })
+
+    var worklist = InstructionWorklist(context)
+    defer { worklist.deinitialize() }
+    for case let load as LoadInst in loadsAndStores where load.loadOwnership == .take && load.loadsFrom(accessPath) {
+      worklist.pushIfNotVisited(load)
+    }
+
+    while let inst = worklist.pop() {
+      if stores.contains(inst) {
+        continue
+      }
+      if exitInsts.contains(inst) {
+        return false
+      }
+      worklist.pushSuccessors(of: inst)
+    }
+    return true
+  }
+}
+
+private extension Type {
+  func isProjectingEntireNonTrivialMembers(path: SmallProjectionPath, in function: Function) -> Bool {
+    let (kind, index, subPath) = path.pop()
+    switch kind {
+    case .root:
+      return true
+    case .structField:
+      guard let fields = getNominalFields(in: function) else {
+        return false
+      }
+      for (fieldIdx, fieldType) in fields.enumerated() {
+        if fieldIdx != index && !fieldType.isTrivial(in: function) {
+          return false
+        }
+      }
+      return fields[index].isProjectingEntireNonTrivialMembers(path: subPath, in: function)
+    case .tupleField:
+      for (elementIdx, elementType) in tupleElements.enumerated() {
+        if elementIdx != index && !elementType.isTrivial(in: function) {
+          return false
+        }
+      }
+      return tupleElements[index].isProjectingEntireNonTrivialMembers(path: subPath, in: function)
+    default:
+      fatalError("path is not materializable")
+    }
+  }
+}
+
+private extension Instruction {
+  /// Returns `true` if this instruction follows the default hoisting heuristic which means it
+  /// is not a terminator, allocation or deallocation and either a hoistable array semantics call or doesn't have memory effects.
+  func canBeHoisted(outOf loop: Loop, _ context: FunctionPassContext) -> Bool {
+    switch self {
+    case is TermInst, is Allocation, is Deallocation:
+      return false
+    case is ApplyInst:
+      switch arraySemanticsCallKind {
+      case .getCount, .getCapacity:
+        if canHoistArraySemanticsCall(to: loop.preheader!.terminator, context) {
+          return true
+        }
+      case .arrayPropsIsNativeTypeChecked:
+        return false
+      default:
+        break
+      }
+    default:
+      break
+    }
+
+    if memoryEffects == .noEffects,
+       !results.contains(where: { $0.ownership == .owned }) {
+      return true
+    }
+
+    return false
+  }
+  
+  func hoist(outOf loop: Loop, _ context: FunctionPassContext) -> Bool {
+    guard operands.allSatisfy({ !loop.contains(block: $0.value.parentBlock) }) else {
+      return false
+    }
+
+    let terminator = loop.preheader!.terminator
+    if canHoistArraySemanticsCall(to: terminator, context) {
+      hoistArraySemanticsCall(before: terminator, context)
+    } else {
+      if let loadCopyInst = self as? LoadInst, loadCopyInst.loadOwnership == .copy {
+        hoist(loadCopyInst: loadCopyInst, outOf: loop, context)
+        return true
+      } else {
+        move(before: terminator, context)
+      }
+    }
+    
+    if let singleValueInst = self as? SingleValueInstruction,
+       !(self is ScopedInstruction || self is AllocStackInst),
+       let identicalInst = (loop.preheader!.instructions.first { otherInst in
+         return singleValueInst != otherInst && singleValueInst.isIdenticalTo(otherInst)
+    }) {
+      guard let identicalSingleValueInst = identicalInst as? SingleValueInstruction else {
+        return true
+      }
+      
+      singleValueInst.replace(with: identicalSingleValueInst, context)
+    }
+
+    return true
+  }
+  
+  private func hoist(loadCopyInst: LoadInst, outOf loop: Loop, _ context: FunctionPassContext) {
+    if loop.hasNoExitBlocks {
+      return
+    }
+    
+    let preheaderBuilder = Builder(before: loop.preheader!.terminator, context)
+    let preheaderLoadBorrow = preheaderBuilder.createLoadBorrow(fromAddress: loadCopyInst.address)
+    
+    let headerBuilder = Builder(before: loadCopyInst, context)
+    let copyValue = headerBuilder.createCopyValue(operand: preheaderLoadBorrow)
+    loadCopyInst.replace(with: copyValue, context)
+    
+    for exitBlock in loop.exitBlocks where !context.deadEndBlocks.isDeadEnd(exitBlock) {
+      assert(exitBlock.hasSinglePredecessor, "Exiting edge should not be critical.")
+      
+      let exitBlockBuilder = Builder(before: exitBlock.instructions.first!, context)
+      exitBlockBuilder.createEndBorrow(of: preheaderLoadBorrow)
+    }
+  }
+  
+  func sink(outOf loop: Loop, _ context: FunctionPassContext) -> Bool {
+    var changed = false
+
+    for exitBlock in loop.exitBlocks where !context.deadEndBlocks.isDeadEnd(exitBlock) {
+      assert(exitBlock.hasSinglePredecessor, "Exiting edge should not be critical.")
+      
+      if changed {
+        copy(before: exitBlock.instructions.first!, context)
+      } else {
+        move(before: exitBlock.instructions.first!, context)
+        changed = true
+      }
+    }
+
+    return changed
+  }
+  
+  /// Returns `true` if `sideEffect` cannot be reordered with a call to this
+  /// global initializer.
+  private func globalInitMayConflictWith(
+    sideEffect: Instruction,
+    _ aliasAnalysis: AliasAnalysis
+  ) -> Bool {
+    switch sideEffect {
+    case let storeInst as StoreInst:
+      return mayReadOrWrite(address: storeInst.destinationOperand.value, aliasAnalysis)
+    case let loadInst as LoadInst:
+      return mayWrite(toAddress: loadInst.operand.value, aliasAnalysis)
+    case is CondFailInst:
+      return false
+    default:
+      return true
+    }
+  }
+  
+  /// Returns `true` if any of the instructions in `sideEffects` cannot be
+  /// reordered with a call to this global initializer (which is in the same basic
+  /// block).
+  func globalInitMayConflictWith(
+    blockSideEffectSegment: StackWithCount<Instruction>.Segment,
+    _ aliasAnalysis: AliasAnalysis
+  ) -> Bool {
+    return blockSideEffectSegment
+      .contains { sideEffect in
+        globalInitMayConflictWith(
+          sideEffect: sideEffect,
+          aliasAnalysis
+        )
+      }
+  }
+
+  /// Returns `true` if any of the instructions in `loopSideEffects` which are
+  /// post-dominated by a call to this global initializer cannot be reordered with
+  /// the call.
+  func globalInitMayConflictWith(
+    loopSideEffects: StackWithCount<Instruction>,
+    _ aliasAnalysis: AliasAnalysis,
+    _ postDomTree: PostDominatorTree
+  ) -> Bool {
+    return loopSideEffects
+      .contains { sideEffect in
+        // Only check instructions in blocks which are "before" (i.e. post-dominated
+        // by) the block which contains the init-call.
+        // Instructions which are before the call in the same block have already
+        // been checked.
+        parentBlock.strictlyPostDominates(sideEffect.parentBlock, postDomTree) &&
+        globalInitMayConflictWith(sideEffect: sideEffect, aliasAnalysis)
+      }
+  }
+}
+
+private extension StoreInst {
+  /// Returns a `true` if this store is a store to `accessPath`.
+  func storesTo(_ accessPath: AccessPath) -> Bool {
+    return accessPath == self.destination.accessPath
+  }
+}
+
+private extension LoadInst {
+  /// Returns `true` if this load instruction loads from `accessPath` or a
+  /// projected address from `accessPath`.
+  func loadsFrom(_ accessPath: AccessPath) -> Bool {
+    return accessPath.getProjection(to: self.address.accessPath)?.isMaterializable ?? false
+  }
+  
+  func overlaps(accessPath: AccessPath) -> Bool {
+    if let path = accessPath.getProjection(to: self.operand.value.accessPath),
+       // If the accessPath is wider than load, it needs to be materializable.
+       // Otherwise we won't be able to project it.
+       path.isMaterializable {
+      // The load is narrower than the access path.
+      return true
+    }
+    
+    if self.operand.value.accessPath.isEqualOrContains(accessPath) {
+      // The load is wider than the access path.
+      return true
+    }
+    
+    return false
+  }
+}
+
+private extension FullApplySite {
+  /// Returns `true` if this apply inst could be safely hoisted.
+  func isSafeReadOnlyApply(_ calleeAnalysis: CalleeAnalysis) -> Bool {
+    guard functionConvention.results.allSatisfy({ $0.convention == .unowned }) else {
+      return false
+    }
+
+    if let callee = referencedFunction,
+       callee.hasSemanticsAttribute("array.props.isNativeTypeChecked") {
+      return false
+    }
+
+    return !calleeAnalysis.getSideEffects(ofApply: self).memory.write
+  }
+  
+  /// Returns `true` if the `sideEffects` contain any memory writes which
+  /// may alias with any memory which is read by this `ApplyInst`.
+  /// - Note: This function should only be called on a read-only apply!
+  func isSafeReadOnlyApply(
+    for sideEffects: StackWithCount<Instruction>,
+    _ aliasAnalysis: AliasAnalysis,
+    _ calleeAnalysis: CalleeAnalysis
+  ) -> Bool {
+    if calleeAnalysis.getSideEffects(ofApply: self).memory == .noEffects {
+      return true
+    }
+
+    // Check if the memory addressed by the argument may alias any writes.
+    for sideEffect in sideEffects {
+      switch sideEffect {
+      case let storeInst as StoreInst:
+        if storeInst.storeOwnership == .assign ||
+           mayRead(fromAddress: storeInst.destination, aliasAnalysis) {
+          return false
+        }
+      case let copyAddrInst as CopyAddrInst:
+        if !copyAddrInst.isInitializationOfDestination ||
+           mayRead(fromAddress: copyAddrInst.destination, aliasAnalysis) {
+          return false
+        }
+      case let fullApplySite as FullApplySite:
+        if calleeAnalysis.getSideEffects(ofApply: fullApplySite).memory.write {
+          return false
+        }
+      case is CondFailInst, is StrongRetainInst, is UnmanagedRetainValueInst,
+        is RetainValueInst, is StrongRetainUnownedInst, is FixLifetimeInst,
+        is KeyPathInst, is DeallocStackInst, is DeallocStackRefInst,
+        is DeallocRefInst:
+        break
+      case let endApply as EndApplyInst:
+        if endApply.beginApply != self {
+          return false
+        }
+      default:
+        if sideEffect.mayWriteToMemory {
+          return false
+        }
+      }
+    }
+
+    return true
+  }
+}
+
+private extension ScopedInstruction {
+  /// Returns `true` if this begin access is safe to hoist.
+  func canScopedInstructionBeHoisted(
+    outOf loop: Loop,
+    analyzedInstructions: AnalyzedInstructions,
+    _ context: FunctionPassContext
+  ) -> Bool {
+    guard endInstructions.allSatisfy({ loop.contains(block: $0.parentBlock) && !($0 is TermInst) }) else {
+      return false
+    }
+    
+    // Instruction specific preconditions
+    switch self {
+    case is BeginAccessInst, is LoadBorrowInst:
+      guard (analyzedInstructions.scopedInsts
+        .allSatisfy { otherScopedInst in
+          guard self != otherScopedInst else { return true }
+
+          return operands.first!.value.accessPath.isDistinct(from: otherScopedInst.operand.value.accessPath)
+        }) else {
+        return false
+      }
+    default:
+      break
+    }
+    
+    var scope = InstructionRange(begin: self, ends: endInstructions, context)
+    defer { scope.deinitialize() }
+    
+    // Instruction specific range related conditions
+    switch self {
+    case is BeginApplyInst:
+      return true // Has already been checked with other full applies.
+    case let loadBorrowInst as LoadBorrowInst:
+      for sideEffectInst in analyzedInstructions.loopSideEffects {
+        if let endBorrow = sideEffectInst as? EndBorrowInst,
+           let begin = endBorrow.borrow as? LoadBorrowInst,
+           begin == self
+        {
+          continue
+        }
+        if sideEffectInst.mayWrite(toAddress: loadBorrowInst.address, context.aliasAnalysis),
+           !scope.contains(sideEffectInst)
+        {
+          return false
+        }
+      }
+      return true
+
+    case let beginAccess as BeginAccessInst:
+      for fullApplyInst in analyzedInstructions.fullApplies {
+        guard mayWriteToMemory && fullApplyInst.mayReadOrWrite(address: beginAccess.address, context.aliasAnalysis) ||
+              !mayWriteToMemory && fullApplyInst.mayWrite(toAddress: beginAccess.address, context.aliasAnalysis) else {
+          continue
+        }
+
+        // After hoisting the begin/end_access the apply will be within the scope, so it must not have a conflicting access.
+        if !scope.contains(fullApplyInst) {
+          return false
+        }
+      }
+      
+      switch beginAccess.address.accessPath.base {
+      case .class, .global:
+        for sideEffect in analyzedInstructions.loopSideEffects where sideEffect.mayRelease {
+          // Since a class might have a deinitializer, hoisting begin/end_access pair could violate
+          // exclusive access if the deinitializer accesses address used by begin_access.
+          if !scope.contains(sideEffect) {
+            return false
+          }
+        }
+
+        return true
+      default:
+        return true
+      }
+    case is BeginBorrowInst, is StoreBorrowInst:
+      // Ensure the value is produced outside the loop.
+      return !loop.contains(block: operands.first!.value.parentBlock)
+    default:
+      return false
+    }
+  }
+}
+
+private extension AccessPath {
+  /// Returns `true` if this access path is invariant in `loop`.
+  func isLoopInvariant(loop: Loop) -> Bool {
+    switch base {
+    case .box(let inst as Instruction), .class(let inst as Instruction),
+      .index(let inst as Instruction),
+      .pointer(let inst as Instruction), .stack(let inst as Instruction),
+      .storeBorrow(let inst as Instruction),
+      .tail(let inst as Instruction):
+      if loop.contains(block: inst.parentBlock) {
+        return false
+      }
+    case .global, .argument:
+      break
+    case .yield(let beginApplyResult):
+      if loop.contains(block: beginApplyResult.parentBlock) {
+        return false
+      }
+    case .unidentified:
+      return false
+    }
+
+    return projectionPath.isConstant
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/NamedReturnValueOptimization.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/NamedReturnValueOptimization.swift
index 6fc0f342145fd..8720b4c057660 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/NamedReturnValueOptimization.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/NamedReturnValueOptimization.swift
@@ -78,7 +78,7 @@ private func findCopyForNRVO(for outArg: FunctionArgument) -> CopyAddrInst? {
   //     %local = alloc_stack $T
   //     store %in to %local : $*T
   //     copy_addr %local to [init] %out : $*T
-  if !copyToArg.isTakeOfSrc {
+  if !copyToArg.isTakeOfSource {
     return nil
   }
 
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjCBridgingOptimization.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjCBridgingOptimization.swift
index 96c9cd67efe64..aa41fce4829e6 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjCBridgingOptimization.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjCBridgingOptimization.swift
@@ -248,7 +248,7 @@ private func removeBridgingCodeInPredecessors(of block: BasicBlock, _ context: F
 /// ```
 ///   switch_enum %0             // returned instruction
 /// some_bb(%1):
-///   %2 = enum #some(%1)        // only in case of ObjC -> Swift briding
+///   %2 = enum #some(%1)        // only in case of ObjC -> Swift bridging
 ///   %3 = apply %bridging(%2)   // returned by `isBridging`
 ///   %4 = enum #some(%3)
 ///   br continue_bb(%4)
@@ -338,7 +338,7 @@ func isBridgeToSwiftCall(_ value: Value) -> ApplyInst? {
   let funcName = bridgingFunc.name
   guard  bridgingFunc.hasSemanticsAttribute("bridgeFromObjectiveC") ||
          // Currently the semantics attribute is not used, so test for specific functions, too.
-         // TODO: remove those checks once the briding functions are annotate with "bridgeFromObjectiveC"
+         // TODO: remove those checks once the bridging functions are annotated with "bridgeFromObjectiveC"
          //       in Foundation.
          //
          // String._unconditionallyBridgeFromObjectiveC(_:)
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjectOutliner.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjectOutliner.swift
index ae70c9eb22787..f0a41bc89ce4f 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjectOutliner.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ObjectOutliner.swift
@@ -109,7 +109,8 @@ private func optimizeObjectAllocation(allocRef: AllocRefInstBase, _ context: Fun
         type: allocRef.type, linkage: .private,
         // Only if it's a COW object we can be sure that the object allocated in the global is not mutated.
         // If someone wants to mutate it, it has to be copied first.
-        isLet: endOfInitInst is EndCOWMutationInst)
+        isLet: endOfInitInst is EndCOWMutationInst,
+        markedAsUsed: false)
 
   constructObject(of: allocRef, inInitializerOf: outlinedGlobal, storesToClassFields, storesToTailElements, context)
   context.erase(instructions: storesToClassFields)
@@ -363,13 +364,13 @@ private func constructObject(of allocRef: AllocRefInstBase,
                              inInitializerOf global: GlobalVariable,
                              _ storesToClassFields: [StoreInst], _ storesToTailElements: [StoreInst],
                              _ context: FunctionPassContext) {
-  var cloner = StaticInitCloner(cloneTo: global, context)
+  var cloner = Cloner(cloneToGlobal: global, context)
   defer { cloner.deinitialize() }
 
   // Create the initializers for the fields
   var objectArgs = [Value]()
   for store in storesToClassFields {
-    objectArgs.append(cloner.clone(store.source as! SingleValueInstruction))
+    objectArgs.append(cloner.cloneRecursively(globalInitValue: store.source as! SingleValueInstruction))
   }
   let globalBuilder = Builder(staticInitializerOf: global, context)
 
@@ -381,7 +382,7 @@ private func constructObject(of allocRef: AllocRefInstBase,
       for elementIdx in 0..<allocRef.numTailElements! {
         let tupleElems = (0..<numTailTupleElems).map { tupleIdx in
             let store = storesToTailElements[elementIdx * numTailTupleElems + tupleIdx]
-            return cloner.clone(store.source as! SingleValueInstruction)
+            return cloner.cloneRecursively(globalInitValue: store.source as! SingleValueInstruction)
         }
         let tuple = globalBuilder.createTuple(type: allocRef.tailAllocatedTypes[0], elements: tupleElems)
         objectArgs.append(tuple)
@@ -389,7 +390,7 @@ private func constructObject(of allocRef: AllocRefInstBase,
     } else {
       // The non-tuple element case.
       for store in storesToTailElements {
-        objectArgs.append(cloner.clone(store.source as! SingleValueInstruction))
+        objectArgs.append(cloner.cloneRecursively(globalInitValue: store.source as! SingleValueInstruction))
       }
     }
   }
@@ -555,7 +556,7 @@ private func replace(findStringCall: ApplyInst,
 
   // Create an "opaque" global variable which is passed as inout to
   // _findStringSwitchCaseWithCache and into which the function stores the "cache".
-  let cacheVar = context.createGlobalVariable(name: name, type: cacheType, linkage: .private, isLet: false)
+  let cacheVar = context.createGlobalVariable(name: name, type: cacheType, linkage: .private, isLet: false, markedAsUsed: false)
 
   let varBuilder = Builder(staticInitializerOf: cacheVar, context)
   let zero = varBuilder.createIntegerLiteral(0, type: wordTy)
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/RedundantLoadElimination.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/RedundantLoadElimination.swift
index 902543bbe7830..8bdd78730c967 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/RedundantLoadElimination.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/RedundantLoadElimination.swift
@@ -12,7 +12,7 @@
 
 import SIL
 
-/// Replaces redundant load instructions with already available values.
+/// Replaces redundant `load` or `copy_addr` instructions with already available values.
 ///
 /// A load is redundant if the loaded value is already available at that point.
 /// This can be via a preceding store to the same address:
@@ -52,6 +52,9 @@ import SIL
 ///     %f2 = load %fa2
 ///     %2 = struct (%f1, %f2)
 ///
+/// This works in a similar fashion for `copy_addr`. If the source value of the `copy_addr` is
+/// already available, the `copy_addr` is replaced by a `store` of the available value.
+///
 /// The algorithm is a data flow analysis which starts at the original load and searches
 /// for preceding stores or loads by following the control flow in backward direction.
 /// The preceding stores and loads provide the "available values" with which the original
@@ -86,6 +89,11 @@ func eliminateRedundantLoads(in function: Function,
                              variant: RedundantLoadEliminationVariant,
                              _ context: FunctionPassContext) -> Bool
 {
+  // FIXME: this skip is a hack for ManualOwnership prototyping, to workaround rdar://161359163
+  if function.performanceConstraints == .manualOwnership && variant == .mandatory {
+    return false
+  }
+
   // Avoid quadratic complexity by limiting the number of visited instructions.
   // This limit is sufficient for most "real-world" functions, by far.
   var complexityBudget = 50_000
@@ -99,7 +107,7 @@ func eliminateRedundantLoads(in function: Function,
     while let i = inst {
       defer { inst = i.previous }
 
-      if let load = inst as? LoadInst {
+      if let load = inst as? LoadingInstruction {
         if !context.continueWithNextSubpassRun(for: load) {
           return changed
         }
@@ -116,7 +124,59 @@ func eliminateRedundantLoads(in function: Function,
   return changed
 }
 
-private func tryEliminate(load: LoadInst, complexityBudget: inout Int, _ context: FunctionPassContext) -> Bool {
+/// Either a `load` or a `copy_addr` (which is equivalent to a load+store).
+private protocol LoadingInstruction: Instruction {
+  var address: Value { get }
+  var type: Type { get }
+  var ownership: Ownership { get }
+  var loadOwnership: LoadInst.LoadOwnership { get }
+  var canLoadValue: Bool { get }
+  func trySplit(_ context: FunctionPassContext) -> Bool
+  func materializeLoadForReplacement(_ context: FunctionPassContext) -> LoadInst
+}
+
+extension LoadInst : LoadingInstruction {
+  // We know that the type is loadable because - well - this is a load.
+  var canLoadValue: Bool { true }
+
+  // Nothing to materialize, because this is already a `load`.
+  func materializeLoadForReplacement(_ context: FunctionPassContext) -> LoadInst { return self }
+}
+
+extension CopyAddrInst : LoadingInstruction {
+  var address: Value { source }
+  var type: Type { address.type.objectType }
+  var typeIsLoadable: Bool { type.isLoadable(in: parentFunction) }
+
+  var ownership: Ownership {
+    if !parentFunction.hasOwnership || type.isTrivial(in: parentFunction) {
+      return .none
+    }
+    // Regardless of if the copy is taking or copying, the loaded value is an owned value.
+    return .owned
+  }
+
+  var canLoadValue: Bool {
+    if !source.type.isLoadable(in: parentFunction) {
+      // Although the original load's type is loadable (obviously), it can be projected-out
+      // from the copy_addr's type which might be not loadable.
+      return false
+    }
+    if !parentFunction.hasOwnership {
+      if !isTakeOfSource || !isInitializationOfDestination {
+        // For simplicity, bail if we would have to insert compensating retains and releases.
+        return false
+      }
+    }
+    return true
+  }
+
+  func materializeLoadForReplacement(_ context: FunctionPassContext) -> LoadInst {
+    return replaceWithLoadAndStore(context).load
+  }
+}
+
+private func tryEliminate(load: LoadingInstruction, complexityBudget: inout Int, _ context: FunctionPassContext) -> Bool {
   switch load.isRedundant(complexityBudget: &complexityBudget, context) {
   case .notRedundant:
     return false
@@ -136,9 +196,12 @@ private func tryEliminate(load: LoadInst, complexityBudget: inout Int, _ context
   }
 }
 
-private extension LoadInst {
+private extension LoadingInstruction {
 
   func isEligibleForElimination(in variant: RedundantLoadEliminationVariant, _ context: FunctionPassContext) -> Bool {
+    if !canLoadValue {
+      return false
+    }
     switch variant {
     case .mandatory, .mandatoryInGlobalInit:
       if loadOwnership == .take {
@@ -171,20 +234,6 @@ private extension LoadInst {
     return true
   }
 
-  enum DataflowResult {
-    case notRedundant
-    case redundant([AvailableValue])
-    case maybePartiallyRedundant(AccessPath)
-
-    init(notRedundantWith subPath: AccessPath?) {
-      if let subPath = subPath {
-        self = .maybePartiallyRedundant(subPath)
-      } else {
-        self = .notRedundant
-      }
-    }
-  }
-
   func isRedundant(complexityBudget: inout Int, _ context: FunctionPassContext) -> DataflowResult {
     return isRedundant(at: address.constantAccessPath, complexityBudget: &complexityBudget, context)
   }
@@ -285,7 +334,7 @@ private extension LoadInst {
   }
 }
 
-private func replace(load: LoadInst, with availableValues: [AvailableValue], _ context: FunctionPassContext) {
+private func replace(load: LoadingInstruction, with availableValues: [AvailableValue], _ context: FunctionPassContext) {
   var ssaUpdater = SSAUpdater(function: load.parentFunction,
                               type: load.type, ownership: load.ownership, context)
 
@@ -318,14 +367,16 @@ private func replace(load: LoadInst, with availableValues: [AvailableValue], _ c
     newValue = ssaUpdater.getValue(inMiddleOf: load.parentBlock)
   }
 
+  let originalLoad = load.materializeLoadForReplacement(context)
+
   // Make sure to keep dependencies valid after replacing the load
-  insertMarkDependencies(for: load, context)
+  insertMarkDependencies(for: originalLoad, context)
 
-  load.replace(with: newValue, context)
+  originalLoad.replace(with: newValue, context)
 }
 
 private func provideValue(
-  for load: LoadInst,
+  for load: LoadingInstruction,
   from availableValue: AvailableValue,
   _ context: FunctionPassContext
 ) -> Value {
@@ -341,9 +392,9 @@ private func provideValue(
                                                         builder: availableValue.getBuilderForProjections(context))
   case .take:
     if projectionPath.isEmpty {
-      return shrinkMemoryLifetime(from: load, to: availableValue, context)
+      return shrinkMemoryLifetime(to: availableValue, context)
     } else {
-      return shrinkMemoryLifetimeAndSplit(from: load, to: availableValue, projectionPath: projectionPath, context)
+      return shrinkMemoryLifetimeAndSplit(to: availableValue, projectionPath: projectionPath, context)
     }
   }
 }
@@ -366,7 +417,7 @@ private func insertMarkDependencies(for load: LoadInst, _ context: FunctionPassC
 private struct MarkDependenceInserter : AddressUseDefWalker {
   let load: LoadInst
   let context: FunctionPassContext
-  
+
   mutating func walkUp(address: Value, path: UnusedWalkingPath) -> WalkResult {
     if let mdi = address as? MarkDependenceInst {
       let builder = Builder(after: load, context)
@@ -375,7 +426,7 @@ private struct MarkDependenceInserter : AddressUseDefWalker {
     }
     return walkUpDefault(address: address, path: path)
   }
-  
+
   mutating func rootDef(address: Value, path: UnusedWalkingPath) -> WalkResult {
     return .continueWalk
   }
@@ -392,7 +443,7 @@ private struct MarkDependenceInserter : AddressUseDefWalker {
 ///     ...
 ///     // replace %2 with %1
 ///
-private func shrinkMemoryLifetime(from load: LoadInst, to availableValue: AvailableValue, _ context: FunctionPassContext) -> Value {
+private func shrinkMemoryLifetime(to availableValue: AvailableValue, _ context: FunctionPassContext) -> Value {
   switch availableValue {
   case .viaLoad(let availableLoad):
     assert(availableLoad.loadOwnership == .copy)
@@ -442,7 +493,7 @@ private func shrinkMemoryLifetime(from load: LoadInst, to availableValue: Availa
 ///     ...
 ///     // replace %3 with %1
 ///
-private func shrinkMemoryLifetimeAndSplit(from load: LoadInst, to availableValue: AvailableValue, projectionPath: SmallProjectionPath, _ context: FunctionPassContext) -> Value {
+private func shrinkMemoryLifetimeAndSplit(to availableValue: AvailableValue, projectionPath: SmallProjectionPath, _ context: FunctionPassContext) -> Value {
   switch availableValue {
   case .viaLoad(let availableLoad):
     assert(availableLoad.loadOwnership == .copy)
@@ -462,6 +513,20 @@ private func shrinkMemoryLifetimeAndSplit(from load: LoadInst, to availableValue
   }
 }
 
+private enum DataflowResult {
+  case notRedundant
+  case redundant([AvailableValue])
+  case maybePartiallyRedundant(AccessPath)
+
+  init(notRedundantWith subPath: AccessPath?) {
+    if let subPath = subPath {
+      self = .maybePartiallyRedundant(subPath)
+    } else {
+      self = .notRedundant
+    }
+  }
+}
+
 /// Either a `load` or `store` which is preceding the original load and provides the loaded value.
 private enum AvailableValue {
   case viaLoad(LoadInst)
@@ -505,7 +570,7 @@ private extension Array where Element == AvailableValue {
   func replaceCopyAddrsWithLoadsAndStores(_ context: FunctionPassContext) -> [AvailableValue] {
     return map {
       if case .viaCopyAddr(let copyAddr) = $0 {
-        return .viaStore(copyAddr.replaceWithLoadAndStore(context))
+        return .viaStore(copyAddr.replaceWithLoadAndStore(context).store)
       } else {
         return $0
       }
@@ -514,7 +579,7 @@ private extension Array where Element == AvailableValue {
 }
 
 private struct InstructionScanner {
-  private let load: LoadInst
+  private let load: LoadingInstruction
   private let accessPath: AccessPath
   private let storageDefBlock: BasicBlock?
   private let aliasAnalysis: AliasAnalysis
@@ -522,7 +587,7 @@ private struct InstructionScanner {
   private(set) var potentiallyRedundantSubpath: AccessPath? = nil
   private(set) var availableValues = Array<AvailableValue>()
 
-  init(load: LoadInst, accessPath: AccessPath, _ aliasAnalysis: AliasAnalysis) {
+  init(load: LoadingInstruction, accessPath: AccessPath, _ aliasAnalysis: AliasAnalysis) {
     self.load = load
     self.accessPath = accessPath
     self.storageDefBlock = accessPath.base.reference?.referenceRoot.parentBlock
@@ -616,7 +681,7 @@ private struct InstructionScanner {
         potentiallyRedundantSubpath = precedingStorePath
       }
 
-    case let preceedingCopy as CopyAddrInst where preceedingCopy.canProvideValue:
+    case let preceedingCopy as CopyAddrInst where preceedingCopy.canLoadValue:
       let copyPath = preceedingCopy.destination.constantAccessPath
       if copyPath.getMaterializableProjection(to: accessPath) != nil {
         availableValues.append(.viaCopyAddr(preceedingCopy))
@@ -712,20 +777,3 @@ private struct Liverange {
     return false
   }
 }
-
-private extension CopyAddrInst {
-  var canProvideValue: Bool {
-    if !source.type.isLoadable(in: parentFunction) {
-      // Although the original load's type is loadable (obviously), it can be projected-out 
-      // from the copy_addr's type which might be not loadable.
-      return false
-    }
-    if !parentFunction.hasOwnership {
-      if !isTakeOfSrc || !isInitializationOfDest {
-        // For simplicity, bail if we would have to insert compensating retains and releases.
-        return false
-      }
-    }
-    return true
-  }
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/SimplificationPasses.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/SimplificationPasses.swift
index 678024ac9c9c2..07b0cac69f05f 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/SimplificationPasses.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/SimplificationPasses.swift
@@ -110,7 +110,7 @@ func runSimplification(on function: Function, _ context: FunctionPassContext,
   } while !worklist.isEmpty
 
   if context.needFixStackNesting {
-    function.fixStackNesting(context)
+    context.fixStackNesting(in: function)
   }
   
   return changed
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/StackPromotion.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/StackPromotion.swift
index a39b04eeb8efd..30994a76c5bf7 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/StackPromotion.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/StackPromotion.swift
@@ -57,7 +57,7 @@ let stackPromotion = FunctionPass(name: "stack-promotion") {
   }
   if needFixStackNesting {
     // Make sure that all stack allocating instructions are nested correctly.
-    function.fixStackNesting(context)
+    context.fixStackNesting(in: function)
   }
 }
 
@@ -286,7 +286,7 @@ private struct ComputeOuterBlockrange : EscapeVisitorWithResult {
     result.insert(operandsDefinitionBlock)
 
     // We need to explicitly add predecessor blocks of phis because they
-    // are not necesesarily visited during the down-walk in `isEscaping()`.
+    // are not necessarily visited during the down-walk in `isEscaping()`.
     // This is important for the special case where there is a back-edge from the
     // inner range to the inner rage's begin-block:
     //
@@ -330,17 +330,3 @@ private extension BasicBlockRange {
     exits.contains { !deadEndBlocks.isDeadEnd($0) && !$0.hasSinglePredecessor }
   }
 }
-
-private func isInLoop(block startBlock: BasicBlock, _ context: FunctionPassContext) -> Bool {
-  var worklist = BasicBlockWorklist(context)
-  defer { worklist.deinitialize() }
-
-  worklist.pushIfNotVisited(contentsOf: startBlock.successors)
-  while let block = worklist.pop() {
-    if block == startBlock {
-      return true
-    }
-    worklist.pushIfNotVisited(contentsOf: block.successors)
-  }
-  return false
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/TempLValueElimination.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/TempLValueElimination.swift
new file mode 100644
index 0000000000000..83bfdb1411371
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/TempLValueElimination.swift
@@ -0,0 +1,315 @@
+//===--- TempLValueElimination.swift ---------------------------------------==//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import AST
+import SIL
+
+/// Eliminates copies from a temporary (an "l-value") to a destination.
+///
+/// ```
+///   %temp = alloc_stack $T
+///   ...                                     -+
+///   store %x to %temp                        | no reads or writes to %destination
+///   ...                                     -+
+///   copy_addr [take] %temp to [init] %destination
+///   dealloc_stack %temp
+/// ```
+/// ->
+/// ```
+///   ...
+///   store %x to %destination
+///   ...
+/// ```
+///
+/// The name TempLValueElimination refers to the TempRValueElimination pass, which performs
+/// a related transformation, just with the temporary on the "right" side.
+///
+/// The pass also performs a peephole optimization on `copy_addr` - `destroy_addr` sequences.
+/// It replaces
+///
+/// ```
+///   copy_addr %source to %destination
+///   destroy_addr %source
+/// ```
+/// ->
+/// ```
+///   copy_addr [take] %source to %destination
+/// ```
+///
+let tempLValueElimination = FunctionPass(name: "temp-lvalue-elimination") {
+  (function: Function, context: FunctionPassContext) in
+
+  for inst in function.instructions {
+    switch inst {
+    case let copy as CopyAddrInst:
+      combineWithDestroy(copy: copy, context)
+      tryEliminate(copy: copy, context)
+    case let store as StoreInst:
+      // Also handle `load`-`store` pairs which are basically the same thing as a `copy_addr`.
+      if let load = store.source as? LoadInst, load.uses.isSingleUse, load.parentBlock == store.parentBlock {
+        tryEliminate(copy: store, context)
+      }
+    default:
+      break
+    }
+  }
+}
+
+private func tryEliminate(copy: CopyLikeInstruction, _ context: FunctionPassContext) {
+  guard let allocStack = copy.sourceAddress as? AllocStackInst,
+        allocStack.isDeallocatedInSameBlock(as: copy)
+  else {
+    return
+  }
+  let isTrivial = allocStack.type.isTrivial(in: copy.parentFunction)
+  guard copy.isTakeOfSource || isTrivial else {
+    return
+  }
+
+  // We need to move all destination address projections at the begin of the alloc_stack liverange,
+  // because we are replacing the alloc_stack uses with the destination.
+  // ```
+  //                                                          %destination = struct_element_addr %1
+  //   stores to %temp                            -->         stores to %destination
+  //   %destination = struct_element_addr %1
+  //   copy_addr [take] %temp to %destination
+  // ```
+  var projections = InstructionSet(context)
+  defer { projections.deinitialize() }
+  let destinationRootAddress = collectMovableProjections(of: copy.destinationAddress, in: &projections)
+
+  // If true we need to explicitly destroy the destination at the begin of the liverange.
+  // ```
+  //                                                          destroy_addr %destination
+  //   stores to %temp                            -->         stores to %destination
+  //   copy_addr [take] %temp to %destination
+  // ```
+  let needDestroyEarly = !copy.isInitializationOfDestination && !isTrivial
+
+  let firstUseOfAllocStack = InstructionList(first: allocStack).first(where: { $0.isUsing(allocStack) }) ??
+                               // The conservative default, if the fist use is not in the alloc_stack's block.
+                               allocStack.parentBlock.terminator
+
+  if firstUseOfAllocStack == copy.loadingInstruction {
+    // The alloc_stack is not written yet at the point of the copy. This is a very unusual corner case
+    // which can only happen if the alloc_stack has an empty type (e.g. `$()`).
+    return
+  }
+
+  let aliasAnalysis = context.aliasAnalysis
+  let calleeAnalysis = context.calleeAnalysis
+
+  if aliasAnalysis.mayAlias(allocStack, copy.destinationAddress) {
+    // Catch the very unusual corner case where the copy is writing back to it's source address - the alloc_stack.
+    return
+  }
+
+  // If exclusivity is checked for the alloc_stack we must not replace it with the copy-destination.
+  // If the copy-destination is also in an access-scope this would result in an exclusivity violation
+  // which was not there before.
+  guard allocStack.uses.users(ofType: BeginAccessInst.self).isEmpty else {
+    return
+  }
+
+  var worklist = InstructionWorklist(context)
+  defer { worklist.deinitialize() }
+  worklist.pushIfNotVisited(firstUseOfAllocStack)
+
+  // Check instructions within the liverange of the alloc_stack.
+  while let inst = worklist.pop() {
+    // If the destination root address is within the liverange it would prevent moving the projections
+    // before the first use. Note that if the defining instruction of `destinationRootAddress` is nil
+    // it can only be a function argument.
+    if inst == destinationRootAddress.definingInstruction {
+      return
+    }
+
+    // Check if the destination is not accessed within the liverange of the temporary.
+    // This is unlikely, because the destination is initialized at the copy.
+    // But still, the destination could contain an initialized value which is destroyed before the copy.
+    if inst.mayReadOrWrite(address: copy.destinationAddress, aliasAnalysis) &&
+        // Needed to treat `init_existential_addr` as not-writing projection.
+        !projections.contains(inst)
+    {
+      return
+    }
+
+    // Check if replacing the alloc_stack with destination would invalidate the alias rules of indirect arguments.
+    if let apply = inst as? FullApplySite,
+       apply.hasInvalidArgumentAliasing(between: allocStack, and: copy.destinationAddress, aliasAnalysis)
+    {
+      return
+    }
+
+    // We must not shrink the liverange of an existing value in the destination.
+    if needDestroyEarly && inst.isDeinitBarrier(calleeAnalysis) {
+      return
+    }
+
+    worklist.pushSuccessors(of: inst, ignoring: copy)
+  }
+
+  if allocStack.isReadOrWritten(after: copy.loadingInstruction, aliasAnalysis) {
+    // Bail in the unlikely case of the alloc_stack is re-initialized after its value has been taken by `copy`.
+    return
+  }
+
+  moveProjections(of: copy.destinationAddress, within: worklist, before: firstUseOfAllocStack, context)
+
+  if needDestroyEarly {
+    // Make sure the destination is uninitialized before the liverange of the temporary.
+    let builder = Builder(before: firstUseOfAllocStack, context)
+    builder.createDestroyAddr(address: copy.destinationAddress)
+  }
+
+  // Replace all uses of the temporary with the destination address.
+  for use in allocStack.uses {
+    switch use.instruction {
+    case let deallocStack as DeallocStackInst:
+      context.erase(instruction: deallocStack)
+    default:
+      use.set(to: copy.destinationAddress, context)
+    }
+  }
+  context.erase(instruction: allocStack)
+  context.erase(instructionIncludingAllUsers: copy.loadingInstruction)
+}
+
+private extension FullApplySite {
+  /// Returns true if after replacing `addr1` with `addr2` the apply would have invalid aliasing of
+  /// indirect arguments.
+  /// An indirect argument (except `@inout_aliasable`) must not alias with another indirect argument.
+  /// For example, if we would replace `addr1` with `addr2` in
+  /// ```
+  ///   apply %f(%addr1, %addr2) : (@in T) -> @out T
+  /// ```
+  /// we would invalidate this rule.
+  func hasInvalidArgumentAliasing(between addr1: Value, and addr2: Value, _ aliasAnalysis: AliasAnalysis) -> Bool {
+    var addr1Accessed = false
+    var addr2Accessed = false
+    var mutatingAccess = false
+    for argOp in argumentOperands {
+      let convention = convention(of: argOp)!
+      if convention.isExclusiveIndirect {
+        if aliasAnalysis.mayAlias(addr1, argOp.value) {
+          addr1Accessed = true
+          if !convention.isGuaranteed {
+            mutatingAccess = true
+          }
+        } else if aliasAnalysis.mayAlias(addr2, argOp.value) {
+          addr2Accessed = true
+          if !convention.isGuaranteed {
+            mutatingAccess = true
+          }
+        }
+      }
+    }
+    return mutatingAccess && addr1Accessed && addr2Accessed
+  }
+}
+
+/// Replace
+/// ```
+///   copy_addr %source to %destination    -->     copy_addr [take] %source to %destination
+///   destroy_addr %source
+/// ```
+private func combineWithDestroy(copy: CopyAddrInst, _ context: FunctionPassContext) {
+  guard !copy.isTakeOfSource else {
+    return
+  }
+
+  // Check if the destroy_addr is after the copy_addr and if there are no memory accesses between them.
+  var debugInsts = Stack<DebugValueInst>(context)
+  defer { debugInsts.deinitialize() }
+
+  for inst in InstructionList(first: copy.next) {
+    switch inst {
+    case let destroy as DestroyAddrInst where destroy.destroyedAddress == copy.source:
+      copy.set(isTakeOfSource: true, context)
+      context.erase(instruction: destroy)
+      // Don't let debug info think that the value is still valid after the `copy [take]`.
+      context.erase(instructions: debugInsts)
+      return
+    case let debugInst as DebugValueInst where debugInst.operand.value == copy.source:
+      debugInsts.append(debugInst)
+    default:
+      if inst.mayReadOrWriteMemory {
+        return
+      }
+    }
+  }
+}
+
+private extension Value {
+  var isMovableProjection: (SingleValueInstruction & UnaryInstruction)? {
+    switch self {
+      case let projectionInst as InitEnumDataAddrInst:          return projectionInst
+      case let projectionInst as StructElementAddrInst:         return projectionInst
+      case let projectionInst as TupleElementAddrInst:          return projectionInst
+      case let projectionInst as UncheckedTakeEnumDataAddrInst: return projectionInst
+      case let projectionInst as InitExistentialAddrInst:       return projectionInst
+      case let projectionInst as RefElementAddrInst:            return projectionInst
+      case let projectionInst as RefTailAddrInst:               return projectionInst
+      case let projectionInst as ProjectBoxInst:                return projectionInst
+      default: return nil
+    }
+  }
+}
+
+private func collectMovableProjections(of address: Value, in projections: inout InstructionSet) -> Value {
+  var a = address
+  while let projection = a.isMovableProjection {
+    projections.insert(projection)
+    a = projection.operand.value
+  }
+  return a
+}
+
+private func moveProjections(
+  of address: Value,
+  within worklist: InstructionWorklist,
+  before insertionPoint: Instruction,
+  _ context: FunctionPassContext
+) {
+  var a = address
+  var ip = insertionPoint
+  while let projection = a.isMovableProjection,
+        worklist.hasBeenPushed(projection)
+  {
+    projection.move(before: ip, context)
+    a = projection.operand.value
+    ip = projection
+  }
+}
+
+private extension AllocStackInst {
+  func isReadOrWritten(after afterInst: Instruction, _ aliasAnalysis: AliasAnalysis) -> Bool {
+    for inst in InstructionList(first: afterInst.next) {
+      if let deallocStack = inst as? DeallocStackInst, deallocStack.allocatedValue == self {
+        return false
+      }
+      if inst.mayReadOrWrite(address: self, aliasAnalysis) {
+        return true
+      }
+    }
+    fatalError("dealloc_stack expected to be in same block as `afterInst`")
+  }
+
+  func isDeallocatedInSameBlock(as inst: Instruction) -> Bool {
+    if let deallocStack = uses.users(ofType: DeallocStackInst.self).singleElement,
+       deallocStack.parentBlock == inst.parentBlock
+    {
+      return true
+    }
+    return false
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/TempRValueElimination.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/TempRValueElimination.swift
new file mode 100644
index 0000000000000..b5cac210cb359
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/TempRValueElimination.swift
@@ -0,0 +1,552 @@
+//===--- TempRValueElimination.swift ---------------------------------------==//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import AST
+import SIL
+
+/// Eliminates copies to `alloc_stack` "temporaries" (r-values).
+///
+/// ```
+///   %temp = alloc_stack $T
+///   copy_addr %src to [init] %temp    -+
+///   ...                                |
+///   %l = load %temp                    | no writes to %src or %temp
+///   ...                                |
+///   destroy_addr %temp                -+
+///   dealloc_stack %temp
+/// ```
+/// ->
+/// ```
+///   %l = load %src
+/// ```
+///
+/// This differs from the copy forwarding algorithm because it handles copy source and dest lifetimes
+/// that are unavoidably overlapping. Instead, it finds cases in which it is easy to determine that
+/// the source is unmodified during the copy destination's lifetime. Thus, the destination can be viewed
+/// as a short-lived "rvalue".
+///
+let tempRValueElimination = FunctionPass(name: "temp-rvalue-elimination") {
+  (function: Function, context: FunctionPassContext) in
+  removeTempRValues(in: function, keepDebugInfo: false, context)
+}
+
+let mandatoryTempRValueElimination = FunctionPass(name: "mandatory-temp-rvalue-elimination") {
+  (function: Function, context: FunctionPassContext) in
+  removeTempRValues(in: function, keepDebugInfo: true, context)
+}
+
+private func removeTempRValues(in function: Function, keepDebugInfo: Bool, _ context: FunctionPassContext) {
+  for inst in function.instructions {
+    switch inst {
+    case let copy as CopyAddrInst:
+      if copy.source == copy.destination {
+        // Remove identity copies which may have been created by an earlier iteration, where another `copy_addr`
+        // copied the `alloc_stack` back to the source location.
+        context.erase(instruction: copy)
+      } else {
+        tryEliminate(copy: copy, keepDebugInfo: keepDebugInfo, context)
+      }
+    case let store as StoreInst:
+      // Also handle `load`-`store` pairs which are basically the same thing as a `copy_addr`.
+      if let load = store.source as? LoadInst, load.uses.isSingleUse, load.parentBlock == store.parentBlock {
+        tryEliminate(copy: store, keepDebugInfo: keepDebugInfo, context)
+      }
+    default:
+      break
+    }
+  }
+}
+
+private func tryEliminate(copy: CopyLikeInstruction, keepDebugInfo: Bool, _ context: FunctionPassContext) {
+
+  guard let (allocStack, lastUseOfAllocStack) =
+          getRemovableAllocStackDestination(of: copy, keepDebugInfo: keepDebugInfo, context) else {
+    return
+  }
+
+  guard extendAccessScopes(beyond: lastUseOfAllocStack, copy: copy, context) else {
+    return
+  }
+
+  if needToInsertDestroy(copy: copy, lastUseOfAllocStack: lastUseOfAllocStack) {
+    Builder.insert(after: lastUseOfAllocStack, context) { builder in
+      builder.createDestroyAddr(address: copy.sourceAddress)
+    }
+  }
+
+  for use in allocStack.uses {
+    switch use.instruction {
+    case is DestroyAddrInst, is DeallocStackInst:
+      context.erase(instruction: use.instruction)
+    case let cai as CopyAddrInst where cai != copy:
+      if cai.isTakeOfSource, !copy.isTakeOfSource {
+        // If the original copy is not taking its source, a `copy_addr` from the `allocStack` must
+        // not take its source either.
+        assert(cai == lastUseOfAllocStack && cai.source == allocStack)
+        cai.set(isTakeOfSource: false, context)
+      }
+      use.set(to: copy.sourceAddress, context)
+    case let load as LoadInst:
+      if load.loadOwnership == .take, !copy.isTakeOfSource {
+        // If the original copy is not taking its source, a `load` from the `allocStack` must
+        // not take its source either.
+        assert(load == lastUseOfAllocStack)
+        load.set(ownership: .copy, context)
+      }
+      use.set(to: copy.sourceAddress, context);
+
+    default:
+      // Note that no operations that may be handled by this default clause can destroy the `allocStack`.
+      // This includes operations that load the value from memory and release it or cast the address
+      // before destroying it.
+      use.set(to: copy.sourceAddress, context);
+    }
+  }
+  context.erase(instruction: allocStack)
+  if keepDebugInfo {
+    Builder(before: copy, context).createDebugStep()
+  }
+  context.erase(instructionIncludingAllUsers: copy.loadingInstruction)
+}
+
+/// Checks if the `copy` is copying into an `alloc_stack` which is removable:
+/// ```
+///   %allocStack = alloc_stack $T
+///   copy_addr %src to [init] %allocStack
+///   ...
+///   %lastUseOfAllocStack = load %allocStack
+/// ```
+private func getRemovableAllocStackDestination(
+  of copy: CopyLikeInstruction, keepDebugInfo: Bool, _ context: FunctionPassContext
+) -> (allocStack: AllocStackInst, lastUseOfAllocStack: Instruction)? {
+  guard copy.isInitializationOfDestination,
+        let allocStack = copy.destinationAddress as? AllocStackInst
+  else {
+    return nil
+  }
+
+  if keepDebugInfo {
+    if allocStack.isFromVarDecl || allocStack.isLexical {
+      return nil
+    }
+  } else {
+    // If the `allocStack` is lexical we can eliminate it if the source of the copy is lexical and
+    // it is live for longer than the `allocStack`.
+    if allocStack.isLexical && !copy.sourceAddress.accessBase.storageIsLexical {
+      return nil
+    }
+  }
+
+  var allocStackUses = UseCollector(copy: copy, context)
+  defer { allocStackUses.deinitialize() }
+
+  // Scan all uses of the `allocStack` to verify only the `copy` is writing to it and that all uses
+  // (except `destroy_addr` and `dealloc_stack`) are in the same basic block.
+  guard allocStackUses.collectUses(of: allocStack) else {
+    return nil
+  }
+
+  // Check that there are no uses of the `allocStack` that precede the copyInst. This can happen with projections.
+  // TODO: We can enable this case if we clone the projections at "load" uses.
+  if allocStack.hasUses(before: copy, context) {
+    return nil
+  }
+
+  // Check if the source is modified within the lifetime of the 'alloc_stack'.
+  guard let lastUseOfAllocStack = getLastUseWhileSourceIsNotModified(of: copy, uses: allocStackUses.uses, context) else {
+    return nil
+  }
+
+  // We cannot insert the destroy of `copy.source` after `lastUseOfAllocStack` if `copy.source` is
+  // re-initialized by exactly this instruction.
+  // This is a corner case, but can happen if `lastUseOfAllocStack` is a `copy_addr`. Example:
+  // ```
+  //   copy_addr [take] %src to [init] %allocStack   // `copy`
+  //   copy_addr [take] %allocStack to [init] %src   // `lastUseOfAllocStack`
+  // ```
+  if copy.isTakeOfSource,
+     lastUseOfAllocStack != copy,
+     !(lastUseOfAllocStack is DestroyAddrInst),
+     lastUseOfAllocStack.mayWrite(toAddress: copy.sourceAddress, context.aliasAnalysis)
+  {
+    return nil
+  }
+
+  // Bail if in non-OSSA the `allocStack` is destroyed in a non-obvious way, e.g. by
+  // ```
+  //   %x = load %allocStack   // looks like a load, but is a `load [take]`
+  //   strong_release %x
+  // ```
+  guard copy.parentFunction.hasOwnership || allocStack.isDestroyedOnAllPaths(context) else {
+    return nil
+  }
+
+  return (allocStack, lastUseOfAllocStack)
+}
+
+/// We need to insert a final destroy if the original `copy` is taking the source but the
+/// `lastUseOfAllocStack` is not taking the `alloc_stack`.
+private func needToInsertDestroy(copy: CopyLikeInstruction, lastUseOfAllocStack: Instruction) -> Bool {
+  if !copy.isTakeOfSource {
+    return false
+  }
+  switch lastUseOfAllocStack {
+  case copy:
+    return true
+  case let cai as CopyAddrInst:
+    if cai.isTakeOfSource {
+      assert(cai.source == copy.destinationAddress, "copy_addr must be not take a projected address")
+      return false
+    }
+    return true
+  case let li as LoadInst:
+    if li.loadOwnership == .take {
+      assert(li.address == copy.destinationAddress, "load must be not take a projected address")
+      return false
+    }
+    return true
+  default:
+    return true
+  }
+}
+
+private extension AllocStackInst {
+  func hasUses(before instruction: Instruction, _ context: FunctionPassContext) -> Bool {
+    var useSet = InstructionSet(context)
+    defer { useSet.deinitialize() }
+
+    useSet.insert(contentsOf: self.users)
+    for inst in InstructionList(first: self) {
+      if inst == instruction {
+        return false
+      }
+      if useSet.contains(inst) {
+        return true
+      }
+    }
+    return false
+  }
+
+  /// In non-OSSA, check if the `alloc_stack` destroyed in an obvious way and not e.g. implicitly by
+  /// ```
+  ///   %x = load %allocStack   // looks like a load, but is a `load [take]`
+  ///   strong_release %x
+  /// ```
+  func isDestroyedOnAllPaths(_ context: FunctionPassContext) -> Bool {
+    var liferange = InstructionRange(begin: self, context)
+    defer { liferange.deinitialize() }
+
+    liferange.insert(contentsOf: uses.ignoreUses(ofType: DeallocStackInst.self).lazy.map { $0.instruction })
+
+    for use in uses {
+      switch use.instruction {
+      case is DeallocStackInst, is DestroyAddrInst:
+        break
+      case let c as CopyAddrInst where c.sourceOperand == use && c.isTakeOfSource:
+        break
+      default:
+        if !liferange.contains(use.instruction) {
+          // A non-destroying instruction is at the end of the liferange -> we are missing a "real" destroy.
+          return false
+        }
+      }
+    }
+    return true
+  }
+}
+
+/// Tries to move an `end_access` down to extend the access scope over all uses of the `alloc_stack`.
+/// For example:
+/// ```
+///   %a = begin_access %src
+///   copy_addr %a to [init] %temp : $*T
+///   end_access %a
+///   use %temp
+/// ```
+/// We must not replace %temp with %a after the `end_access`. Instead we try to move the `end_access`
+/// after the last use.
+private func extendAccessScopes(beyond lastUse: Instruction, copy: CopyLikeInstruction,
+                                _ context: FunctionPassContext) -> Bool
+{
+  var endAccessToMove: EndAccessInst? = nil
+
+  for inst in InstructionList(first: copy.next) {
+    if let endAccess = inst as? EndAccessInst {
+      // To keep things simple, we can just move a single `end_access`. Also, we cannot move an
+      // `end_access` over a (non-aliasing) other `end_access`.
+      if endAccessToMove != nil {
+        return false
+      }
+      if context.aliasAnalysis.mayAlias(copy.sourceAddress, endAccess.beginAccess.address),
+         // There cannot be any aliasing modifying accesses within the liverange of the `alloc_stack`,
+         // because we would have cought this in `getLastUseWhileSourceIsNotModified`.
+         // But there are cases where `aliasAnalysis.mayAlias` is less precise than `Instruction.mayWrite`.
+         // Therefore, just ignore any non-read accesses.
+         endAccess.beginAccess.accessKind == .read
+      {
+        // We cannot move instructions beyond the block's terminator.
+        if lastUse is TermInst {
+          return false
+        }
+        endAccessToMove = endAccess
+      }
+    } else if let endAccessToMove {
+      // We cannot move an `end_access` over a `begin_access`. This would destroy the proper nesting of accesses.
+      if inst is BeginAccessInst || inst is BeginUnpairedAccessInst {
+        return false
+      }
+      // Don't extend a read-access scope over a (potential) write.
+      // Note that `inst` can be a function call containing other access scopes. But doing the `inst.mayWrite`
+      // check, we know that the function can only contain read accesses (to the same memory location).
+      // So it's fine to move `endAccessToMove` even over such a function call.
+      if inst.mayWrite(toAddress: endAccessToMove.beginAccess.address, context.aliasAnalysis) {
+        return false
+      }
+    }
+    if inst == lastUse {
+      break
+    }
+  }
+  if let endAccessToMove {
+    endAccessToMove.move(before: lastUse.next!, context)
+  }
+
+  return true
+}
+
+/// Checks if the source of `copy` is not modified within the `alloc_stack`'s lifetime, i.e. is not modified
+/// before the last use of `uses`.
+///
+/// If there are no source modifications with the lifetime, returns the last user. Otherwise returns nil.
+///
+/// Unfortunately, we cannot simply use the destroy points as the lifetime end, because they can be in a
+/// different basic block. Instead we look for the last non-destroy, non-dealloc use.
+private func getLastUseWhileSourceIsNotModified(of copy: CopyLikeInstruction,
+                                                uses: InstructionSetWithCount,
+                                                _ context: FunctionPassContext) -> Instruction?
+{
+  if uses.isEmpty {
+    return copy
+  }
+  var numUsesFound = 0
+  let aliasAnalysis = context.aliasAnalysis
+
+  // We already checked that the useful lifetime of the `alloc_stack` ends in the same block as the `copy`.
+  // Therefore we can limit our search to the instructions of this block.
+  for inst in InstructionList(first: copy.loadingInstruction.next) {
+    if uses.contains(inst) {
+      numUsesFound += 1
+    }
+
+    // If this is the last use of the `alloc_stack` we are okay. After this point, modifications to the source
+    // don't matter anymore.
+    // Note that we are assuming here that if an instruction reads and writes to the source at the same time
+    // (like a `copy_addr` could do), the write takes effect after the read.
+    if numUsesFound == uses.count {
+      // Function calls are an exception: in a called function a potential modification of `copy.source`
+      // could occur _before_ the read of the `alloc_stack`.
+      switch inst {
+      case is FullApplySite, is YieldInst:
+        if inst.mayWrite(toAddress: copy.sourceAddress, aliasAnalysis) {
+          return nil
+        }
+        return inst
+      default:
+        return inst
+      }
+    }
+
+    if inst.mayWrite(toAddress: copy.sourceAddress, aliasAnalysis) {
+      return nil
+    }
+  }
+  // For some reason, not all normal uses have been seen between the copy and the end of the initialization
+  // block. We should never reach here.
+  return nil
+}
+
+/// Collects all uses of the `alloc_stack`.
+private struct UseCollector : AddressDefUseWalker {
+  private(set) var uses: InstructionSetWithCount
+  private let copy: CopyLikeInstruction
+
+  init(copy: CopyLikeInstruction, _ context: FunctionPassContext) {
+    self.uses = InstructionSetWithCount(context)
+    self.copy = copy
+  }
+
+  mutating func collectUses(of allocStack: AllocStackInst) -> Bool {
+    for use in allocStack.uses {
+      switch use.instruction {
+      case copy:
+        break
+      case is DeallocStackInst:
+        // Deallocations are allowed to be in a different block.
+        break
+      case let destroyAddr as DestroyAddrInst:
+        if !destroyAddr.parentFunction.hasOwnership && copy.isTakeOfSource {
+          // In non-OSSA mode, for the purpose of inserting the destroy of `copy.source`, we have to be
+          // conservative and assume that the lifetime of `allocStack` goes beyond it's last use - until
+          // the final `destroy_addr`. Otherwise we would risk inserting the destroy too early. Therefore we
+          // treat the `destroy_addr` as any other use of `allocStack` and require it to be in the same block.
+          if destroyAddr.parentBlock != copy.parentBlock {
+            return false
+          }
+          uses.insert(destroyAddr)
+        }
+      default:
+        if walkDown(address: use, path: UnusedWalkingPath()) == .abortWalk {
+          return false
+        }
+      }
+    }
+    return true
+  }
+
+  public mutating func walkDown(address operand: Operand, path: UnusedWalkingPath) -> WalkResult {
+    if operand.instruction.parentBlock != copy.parentBlock {
+      // All normal uses (except destroys and `dealloc_stack`) must be in the initialization block.
+      return .abortWalk
+    }
+    switch operand.instruction {
+    case let openExistential as OpenExistentialAddrInst:
+      if !openExistential.isImmutable {
+        return.abortWalk
+      }
+    case let takeEnum as UncheckedTakeEnumDataAddrInst:
+      // In certain cases, `unchecked_take_enum_data_addr` invalidates the underlying memory. Therefore,
+      // by default` we can not look through it... but this is not true in the case of `Optional`.
+      // This is an important case for us to handle, so handle it here.
+      if !takeEnum.enum.type.isOptional {
+        return .abortWalk
+      }
+    case let beginAccess as BeginAccessInst:
+      if beginAccess.accessKind != .read {
+        return .abortWalk
+      }
+      // We don't have to walk down the `beginAccess` result, because the access kind "read" already
+      // guarantees that there are no writes to the `beginAccess` result address. But we have to register
+      // the `end_access`es as uses to correctly mark the end-of-lifetime of the `alloc_stack`.
+      // ```
+      //   %addr = begin_access [read]
+      //      ... // there can be no writes to %addr here
+      //   end_access %addr   // <- This is where the use actually ends.
+      // ```
+      for endAccess in beginAccess.endAccessInstructions {
+        if endAccess.parentBlock != copy.parentBlock {
+          return .abortWalk
+        }
+        uses.insert(endAccess)
+      }
+      return .continueWalk
+    default:
+      break
+    }
+    return walkDownDefault(address: operand, path: path)
+  }
+
+  mutating func leafUse(address: Operand, path: UnusedWalkingPath) -> WalkResult {
+    if address.isTypeDependent {
+      return .continueWalk
+    }
+
+    // Only allow uses that cannot destroy their operand. We need to be sure that replacing all the uses
+    // with the copy source doesn't destroy the source.
+    switch address.instruction {
+    case let beginApply as BeginApplyInst:
+      // Extend the lifetime of the `alloc_stack` to the 'end_apply'/'abort_apply'.
+      for tokenUse in beginApply.token.uses {
+        if tokenUse.instruction.parentBlock != copy.parentBlock {
+          return .abortWalk
+        }
+        uses.insert(tokenUse.instruction)
+      }
+      return visitApply(address: address, apply: beginApply)
+
+    case let partialApply as PartialApplyInst:
+      if !partialApply.isOnStack {
+        return .abortWalk
+      }
+      return visitApply(address: address, apply: partialApply)
+
+    case let apply as ApplySite:
+      // Remaining applies: `apply` and `try_apply`
+      return visitApply(address: address, apply: apply)
+
+    case let yield as YieldInst:
+      if !yield.convention(of: address).isGuaranteed {
+        return .abortWalk
+      }
+      uses.insert(yield)
+      return .continueWalk
+
+    case let addrCast as UncheckedAddrCastInst:
+      return walkDownUses(ofAddress: addrCast, path: UnusedWalkingPath())
+
+    case let load as LoadInst:
+      if load.loadOwnership == .take,
+          // Only accept `load [take]` if it takes the whole `alloc_stack`. A `load [take]` from
+          // a projection would destroy only a part of the `alloc_stack` and we don't handle this.
+          load.address != copy.destinationAddress
+      {
+        return .abortWalk
+      }
+      uses.insert(load)
+      return .continueWalk
+
+    case let loadBorrow as LoadBorrowInst:
+      uses.insert(loadBorrow)
+      for end in loadBorrow.uses.endingLifetime.users {
+        if end.parentBlock != copy.parentBlock || end is BranchInst {
+          return .abortWalk
+        }
+        uses.insert(end)
+      }
+      return .continueWalk
+
+    case let fixLifetime as FixLifetimeInst:
+      // After removing the `alloc_stack` the `fix_lifetime` will apply for the `copy.source`.
+      uses.insert(fixLifetime)
+      return .continueWalk
+
+    case let copyFromStack as CopyAddrInst:
+      if copyFromStack.destinationOperand == address {
+        return .abortWalk
+      }
+      // As with `load [take]`, only accept `copy_addr [take]` if it takes the whole `alloc_stack`.
+      if copyFromStack.isTakeOfSource && copyFromStack.source != copy.destinationAddress {
+        return .abortWalk
+      }
+      uses.insert(copyFromStack)
+      return .continueWalk
+
+    default:
+      return .abortWalk
+    }
+  }
+
+  private mutating func visitApply(address: Operand, apply: ApplySite) -> WalkResult {
+    if !apply.convention(of: address)!.isGuaranteed {
+      return .abortWalk
+    }
+    uses.insert(apply)
+    return .continueWalk
+  }
+
+  public mutating func unmatchedPath(address: Operand, path: UnusedWalkingPath) -> WalkResult {
+    return .abortWalk
+  }
+
+  mutating func deinitialize() {
+    uses.deinitialize()
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/CMakeLists.txt b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/CMakeLists.txt
index 1cb0130076f90..02a9a02e01f90 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/CMakeLists.txt
@@ -19,25 +19,31 @@ swift_compiler_sources(Optimizer
   SimplifyCondBranch.swift
   SimplifyCondFail.swift
   SimplifyConvertEscapeToNoEscape.swift
+  SimplifyCopyBlock.swift
   SimplifyCopyValue.swift
   SimplifyDebugStep.swift
   SimplifyDestroyValue.swift
   SimplifyDestructure.swift
+  SimplifyEndCOWMutationAddr.swift
+  SimplifyExplicitCopy.swift
   SimplifyFixLifetime.swift
   SimplifyGlobalValue.swift
   SimplifyInitEnumDataAddr.swift
   SimplifyKeyPath.swift
   SimplifyLoad.swift
+  SimplifyMarkDependence.swift
   SimplifyMisc.swift
   SimplifyPartialApply.swift
   SimplifyPointerToAddress.swift
   SimplifyRefCasts.swift
   SimplifyRetainReleaseValue.swift
   SimplifyStrongRetainRelease.swift
+  SimplifyStruct.swift
   SimplifyStructExtract.swift
   SimplifySwitchEnum.swift
   SimplifyTuple.swift
   SimplifyTupleExtract.swift
+  SimplifyUncheckedAddrCast.swift
   SimplifyUncheckedEnumData.swift
   SimplifyValueToBridgeObject.swift
   SimplifyWitnessMethod.swift)
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyAllocStack.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyAllocStack.swift
index 85c6d297e6671..4af01ed30b8a7 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyAllocStack.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyAllocStack.swift
@@ -179,7 +179,8 @@ private extension AllocStackInst {
   ///   use %3
   /// ```
   func optimizeExistential(_ context: SimplifyContext) -> Bool {
-    guard type.isExistential || type.isExistentialArchetype,
+    // TODO: support non-root existential archetypes
+    guard type.isExistential || type.isRootExistentialArchetype,
           let concreteFormalType = getConcreteTypeOfExistential()
     else {
       return false
@@ -206,21 +207,21 @@ private extension AllocStackInst {
           iea.replace(with: newAlloc, context)
         }
       case let oea as OpenExistentialAddrInst:
-        assert(oea.uses.ignoreUsers(ofType: DestroyAddrInst.self).isEmpty)
+        assert(oea.uses.ignoreUses(ofType: DestroyAddrInst.self).isEmpty)
         oea.replace(with: newAlloc, context)
       case let cab as CheckedCastAddrBranchInst:
         let builder = Builder(before: cab, context)
         builder.createCheckedCastAddrBranch(
           source: newAlloc, sourceFormalType: concreteFormalType,
           destination: cab.destination, targetFormalType: cab.targetFormalType,
-          isolatedConformances: cab.isolatedConformances,
+          options: cab.checkedCastOptions,
           consumptionKind: cab.consumptionKind,
           successBlock: cab.successBlock, failureBlock: cab.failureBlock)
         context.erase(instruction: cab)
       case let ucca as UnconditionalCheckedCastAddrInst:
         let builder = Builder(before: ucca, context)
         builder.createUnconditionalCheckedCastAddr(
-          isolatedConformances: ucca.isolatedConformances,
+          options: ucca.checkedCastOptions,
           source: newAlloc, sourceFormalType: concreteFormalType,
           destination: ucca.destination, targetFormalType: ucca.targetFormalType)
         context.erase(instruction: ucca)
@@ -246,7 +247,7 @@ private extension AllocStackInst {
            is DebugValueInst:
         break
       case let oea as OpenExistentialAddrInst:
-        if !oea.uses.ignoreUsers(ofType: DestroyAddrInst.self).isEmpty {
+        if !oea.uses.ignoreUses(ofType: DestroyAddrInst.self).isEmpty {
           return nil
         }
       case let iea as InitExistentialAddrInst:
@@ -257,11 +258,15 @@ private extension AllocStackInst {
       case is CheckedCastAddrBranchInst, is UnconditionalCheckedCastAddrInst:
         // To construct a new cast instruction we need a formal type.
         requiresLegalFormalType = true
-        fallthrough
-      case is UncheckedAddrCastInst:
         if use != use.instruction.operands[0] {
           return nil
         }
+      case is UncheckedAddrCastInst:
+        if self.type.isExistential {
+          // Bail if the address of the original existential escapes.
+          // This is not a problem if the alloc_stack already contains the opened existential.
+          return nil
+        }
       default:
         return nil
       }
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyApply.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyApply.swift
index 7def68d638958..5755f8b998d01 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyApply.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyApply.swift
@@ -28,6 +28,9 @@ extension ApplyInst : OnoneSimplifiable, SILCombineSimplifiable {
     if tryRemoveArrayCast(apply: self, context) {
       return
     }
+    if tryOptimizeEnumComparison(apply: self, context) {
+      return
+    }
     if !context.preserveDebugInfo {
       _ = tryReplaceExistentialArchetype(of: self, context)
     }
@@ -110,6 +113,49 @@ private func tryRemoveArrayCast(apply: ApplyInst, _ context: SimplifyContext) ->
   return true
 }
 
+/// Optimize (the very inefficient) RawRepresentable comparison to a simple compare of enum tags.
+/// For example,
+/// ```
+///   enum E: String {
+///     case  a, b, c
+///   }
+/// ```
+/// is compared by getting the raw values of both operands and doing a string compare.
+/// This peephole optimizations replaces the call to such a comparison function with a direct compare of
+/// the enum tags, which boils down to a single integer comparison instruction.
+///
+private func tryOptimizeEnumComparison(apply: ApplyInst, _ context: SimplifyContext) -> Bool {
+  guard let callee = apply.referencedFunction,
+        apply.arguments.count == 2,
+        callee.hasSemanticsAttribute("rawrepresentable.is_equal"),
+        apply.type.isStruct
+  else {
+    return false
+  }
+  let lhs = apply.arguments[0]
+  let rhs = apply.arguments[1]
+  guard let enumDecl = lhs.type.nominal as? EnumDecl,
+        enumDecl.hasRawType,
+        !enumDecl.isResilient(in: apply.parentFunction),
+        !enumDecl.hasClangNode,
+        lhs.type.isAddress,
+        lhs.type == rhs.type
+  else {
+    return false
+  }
+  let builder = Builder(before: apply, context)
+  let tagType = context.getBuiltinIntegerType(bitWidth: 32)
+  let lhsTag = builder.createBuiltin(name: "getEnumTag", type: tagType,
+                                     substitutions: apply.substitutionMap, arguments: [lhs])
+  let rhsTag = builder.createBuiltin(name: "getEnumTag", type: tagType,
+                                     substitutions: apply.substitutionMap, arguments: [rhs])
+  let builtinBoolType = context.getBuiltinIntegerType(bitWidth: 1)
+  let cmp = builder.createBuiltin(name: "cmp_eq_Int32", type: builtinBoolType, arguments: [lhsTag, rhsTag])
+  let booleanResult = builder.createStruct(type: apply.type, elements: [cmp])
+  apply.replace(with: booleanResult, context)
+  return true
+}
+
 /// If the apply uses an existential archetype (`@opened("...")`) and the concrete type is known,
 /// replace the existential archetype with the concrete type
 ///   1. in the apply's substitution map
@@ -131,7 +177,7 @@ private func tryReplaceExistentialArchetype(of apply: ApplyInst, _ context: Simp
 
     let newApply = builder.createApply(
       function: apply.callee,
-      apply.replaceOpenedArchetypeInSubstituations(withConcreteType: concreteType, context),
+      apply.replaceOpenedArchetypeInSubstitutions(withConcreteType: concreteType, context),
       arguments: apply.replaceExistentialArchetypeInArguments(withConcreteType: concreteType, context),
       isNonThrowing: apply.isNonThrowing, isNonAsync: apply.isNonAsync,
       specializationInfo: apply.specializationInfo)
@@ -151,7 +197,7 @@ private func tryReplaceExistentialArchetype(of tryApply: TryApplyInst, _ context
 
     builder.createTryApply(
       function: tryApply.callee,
-      tryApply.replaceOpenedArchetypeInSubstituations(withConcreteType: concreteType, context),
+      tryApply.replaceOpenedArchetypeInSubstitutions(withConcreteType: concreteType, context),
       arguments: tryApply.replaceExistentialArchetypeInArguments(withConcreteType: concreteType, context),
       normalBlock: tryApply.normalBlock, errorBlock: tryApply.errorBlock,
       isNonAsync: tryApply.isNonAsync,
@@ -170,8 +216,9 @@ private extension FullApplySite {
     // Make sure that existential archetype _is_ a replacement type and not e.g. _contained_ in a
     // replacement type, like
     //    apply %1<Array<@opened("...")>()
-    guard substitutionMap.replacementTypes.contains(where: { $0.isExistentialArchetype }),
-          substitutionMap.replacementTypes.allSatisfy({ $0.isExistentialArchetype || !$0.hasLocalArchetype })
+    // TODO: support non-root existential archetypes
+    guard substitutionMap.replacementTypes.contains(where: { $0.isRootExistentialArchetype }),
+          substitutionMap.replacementTypes.allSatisfy({ $0.isRootExistentialArchetype || !$0.hasLocalArchetype })
     else {
       return false
     }
@@ -191,9 +238,9 @@ private extension FullApplySite {
       let type = value.type
       // Allow three cases:
              // case 1. the argument _is_ the existential archetype
-      return type.isExistentialArchetype ||
+      return type.isRootExistentialArchetype ||
              // case 2. the argument _is_ a metatype of the existential archetype
-             (type.isMetatype && type.canonicalType.instanceTypeOfMetatype.isExistentialArchetype) ||
+             (type.isMetatype && type.canonicalType.instanceTypeOfMetatype.isRootExistentialArchetype) ||
              // case 3. the argument has nothing to do with the existential archetype (or any other local archetype)
              !type.hasLocalArchetype
     }
@@ -223,7 +270,7 @@ private extension FullApplySite {
     return Array(newArgs)
   }
 
-  func replaceOpenedArchetypeInSubstituations(
+  func replaceOpenedArchetypeInSubstitutions(
     withConcreteType concreteType: CanonicalType,
     _ context: SimplifyContext
   ) -> SubstitutionMap {
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBeginAndLoadBorrow.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBeginAndLoadBorrow.swift
index 2bb3e1c21c289..0771dd69555d0 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBeginAndLoadBorrow.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBeginAndLoadBorrow.swift
@@ -29,7 +29,7 @@ extension BeginBorrowInst : OnoneSimplifiable, SILCombineSimplifiable {
 
 extension LoadBorrowInst : Simplifiable, SILCombineSimplifiable {
   func simplify(_ context: SimplifyContext) {
-    if uses.ignoreDebugUses.ignoreUsers(ofType: EndBorrowInst.self).isEmpty {
+    if uses.ignoreDebugUses.ignoreUses(ofType: EndBorrowInst.self).isEmpty {
       context.erase(instructionIncludingAllUsers: self)
       return
     }
@@ -52,7 +52,7 @@ extension LoadBorrowInst : Simplifiable, SILCombineSimplifiable {
 
   private func tryCombineWithCopy(_ context: SimplifyContext) {
     let forwardedValue = lookThroughSingleForwardingUses()
-    guard let singleUser = forwardedValue.uses.ignoreUsers(ofType: EndBorrowInst.self).singleUse?.instruction,
+    guard let singleUser = forwardedValue.uses.ignoreUses(ofType: EndBorrowInst.self).singleUse?.instruction,
           let copy = singleUser as? CopyValueInst,
           copy.parentBlock == self.parentBlock else {
       return
@@ -81,13 +81,13 @@ private func tryReplaceBorrowWithOwnedOperand(beginBorrow: BeginBorrowInst, _ co
 private func removeBorrowOfThinFunction(beginBorrow: BeginBorrowInst, _ context: SimplifyContext) {
   guard let thin2thickFn = beginBorrow.borrowedValue as? ThinToThickFunctionInst,
         // For simplicity don't go into the trouble of removing reborrow phi arguments.
-        beginBorrow.uses.filterUsers(ofType: BranchInst.self).isEmpty else
+        beginBorrow.uses.filterUses(ofType: BranchInst.self).isEmpty else
   {
     return
   }
   // `thin_to_thick_function` has "none" ownership and is compatible with guaranteed values.
   // Therefore the `begin_borrow` is not needed.
-  beginBorrow.uses.ignoreUsers(ofType: EndBorrowInst.self).replaceAll(with: thin2thickFn, context)
+  beginBorrow.uses.ignoreUses(ofType: EndBorrowInst.self).replaceAll(with: thin2thickFn, context)
   context.erase(instructionIncludingAllUsers: beginBorrow)
 }
 
@@ -110,7 +110,7 @@ private func tryReplaceCopy(
   withCopiedOperandOf beginBorrow: BeginBorrowInst,
   _ context: SimplifyContext
 ) -> Bool {
-  guard let singleUser = forwardedValue.uses.ignoreUsers(ofType: EndBorrowInst.self).singleUse?.instruction,
+  guard let singleUser = forwardedValue.uses.ignoreUses(ofType: EndBorrowInst.self).singleUse?.instruction,
         let copy = singleUser as? CopyValueInst,
         copy.parentBlock == beginBorrow.parentBlock else {
     return false
@@ -153,7 +153,7 @@ private extension Value {
   /// ```
   /// Returns self if this value has no uses which are ForwardingInstructions.
   func lookThroughSingleForwardingUses() -> Value {
-    if let singleUse = uses.ignoreUsers(ofType: EndBorrowInst.self).singleUse,
+    if let singleUse = uses.ignoreUses(ofType: EndBorrowInst.self).singleUse,
        let fwdInst = singleUse.instruction as? (SingleValueInstruction & ForwardingInstruction),
        fwdInst.canConvertToOwned,
        fwdInst.isSingleForwardedOperand(singleUse),
@@ -165,7 +165,7 @@ private extension Value {
   }
 
   var allUsesCanBeConvertedToOwned: Bool {
-    let relevantUses = uses.ignoreUsers(ofType: EndBorrowInst.self)
+    let relevantUses = uses.ignoreUses(ofType: EndBorrowInst.self)
     return relevantUses.allSatisfy { $0.canAccept(ownership: .owned) }
   }
 
@@ -175,7 +175,7 @@ private extension Value {
   }
 
   func replaceAllDestroys(with replacement: Value, _ context: SimplifyContext) {
-    uses.filterUsers(ofType: DestroyValueInst.self).replaceAll(with: replacement, context)
+    uses.filterUses(ofType: DestroyValueInst.self).replaceAll(with: replacement, context)
   }
 }
 
@@ -187,7 +187,7 @@ private extension Instruction {
       // The value and instruction are in the same block. All uses are dominated by both.
       return true
     }
-    let destroys = value.uses.filterUsers(ofType: DestroyValueInst.self)
+    let destroys = value.uses.filterUses(ofType: DestroyValueInst.self)
     return destroys.allSatisfy({ $0.instruction.parentBlock == parentBlock})
   }
 }
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBeginCOWMutation.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBeginCOWMutation.swift
index cd92ca9a3b9bd..5cad01b2e12e8 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBeginCOWMutation.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBeginCOWMutation.swift
@@ -65,8 +65,8 @@ private extension BeginCOWMutationInst {
       return
     }
     let builder = Builder(before: self, location: location, context)
-    let zero = builder.createIntegerLiteral(0, type: uniquenessResult.type);
-    uniquenessResult.uses.replaceAll(with: zero, context)
+    let falseLiteral = builder.createBoolLiteral(false)
+    uniquenessResult.uses.replaceAll(with: falseLiteral, context)
   }
 
   func optimizeEmptyBeginEndPair(_ context: SimplifyContext) -> Bool {
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBuiltin.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBuiltin.swift
index 0af3cc3d9ab02..c761086764164 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBuiltin.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBuiltin.swift
@@ -12,7 +12,7 @@
 
 import SIL
 
-extension BuiltinInst : OnoneSimplifiable {
+extension BuiltinInst : OnoneSimplifiable, SILCombineSimplifiable {
   func simplify(_ context: SimplifyContext) {
     switch id {
       case .IsConcrete:
@@ -53,8 +53,10 @@ extension BuiltinInst : OnoneSimplifiable {
         constantFoldIntegerEquality(isEqual: true, context)
       case .ICMP_NE:
         constantFoldIntegerEquality(isEqual: false, context)
+      case .Xor:
+        simplifyNegation(context)
       default:
-        if let literal = constantFold(context) {
+        if let literal = context.constantFold(builtin: self) {
           uses.replaceAll(with: literal, context)
         }
     }
@@ -79,7 +81,7 @@ private extension BuiltinInst {
       return
     }
     let builder = Builder(before: self, context)
-    let result = builder.createIntegerLiteral(hasArchetype ? 0 : 1, type: type)
+    let result = builder.createBoolLiteral(!hasArchetype)
     uses.replaceAll(with: result, context)
     context.erase(instruction: self)
   }
@@ -92,7 +94,7 @@ private extension BuiltinInst {
       return
     }
     let builder = Builder(before: self, context)
-    let result = builder.createIntegerLiteral(equal ? 1 : 0, type: type)
+    let result = builder.createBoolLiteral(equal)
 
     uses.replaceAll(with: result, context)
   }
@@ -165,6 +167,11 @@ private extension BuiltinInst {
     case .Sizeof:
       value = ty.getStaticSize(context: context)
     case .Strideof:
+      if isUsedAsStrideOfIndexRawPointer(context) {
+        // Constant folding `stride` would prevent index_raw_pointer simplification.
+        // See `simplifyIndexRawPointer` in SimplifyPointerToAddress.swift.
+        return
+      }
       value = ty.getStaticStride(context: context)
     case .Alignof:
       value = ty.getStaticAlignment(context: context)
@@ -181,7 +188,33 @@ private extension BuiltinInst {
     uses.replaceAll(with: literal, context)
     context.erase(instruction: self)
   }
-  
+
+  private func isUsedAsStrideOfIndexRawPointer(_ context: SimplifyContext) -> Bool {
+    var worklist = ValueWorklist(context)
+    defer { worklist.deinitialize() }
+    worklist.pushIfNotVisited(self)
+    while let v = worklist.pop() {
+      for use in v.uses {
+        switch use.instruction {
+        case let builtin as BuiltinInst:
+          switch builtin.id {
+          case .SMulOver, .TruncOrBitCast, .SExtOrBitCast, .ZExtOrBitCast:
+            worklist.pushIfNotVisited(builtin)
+          default:
+            break
+          }
+        case let tupleExtract as TupleExtractInst where tupleExtract.fieldIndex == 0:
+          worklist.pushIfNotVisited(tupleExtract)
+        case is IndexRawPointerInst:
+          return true
+        default:
+          break
+        }
+      }
+    }
+    return false
+  }
+
   func optimizeArgumentToThinMetatype(argument: Int, _ context: SimplifyContext) {
     let type: Type
 
@@ -207,7 +240,7 @@ private extension BuiltinInst {
     if constantFoldStringNullPointerCheck(isEqual: isEqual, context) {
       return
     }
-    if let literal = constantFold(context) {
+    if let literal = context.constantFold(builtin: self) {
       uses.replaceAll(with: literal, context)
     }
   }
@@ -217,13 +250,60 @@ private extension BuiltinInst {
        operands[0].value.lookThroughScalarCasts is StringLiteralInst
     {
       let builder = Builder(before: self, context)
-      let result = builder.createIntegerLiteral(isEqual ? 0 : 1, type: type)
+      let result = builder.createBoolLiteral(!isEqual)
       uses.replaceAll(with: result, context)
       context.erase(instruction: self)
       return true
     }
     return false
   }
+
+  /// Replaces a builtin "xor", which negates its operand comparison
+  /// ```
+  ///   %3 = builtin "cmp_slt_Int64"(%1, %2) : $Builtin.Int1
+  ///   %4 = integer_literal $Builtin.Int1, -1
+  ///   %5 = builtin "xor_Int1"(%3, %4) : $Builtin.Int1
+  /// ```
+  /// with the negated comparison
+  /// ```
+  ///   %5 = builtin "cmp_ge_Int64"(%1, %2) : $Builtin.Int1
+  /// ```
+  func simplifyNegation(_ context: SimplifyContext) {
+    assert(id == .Xor)
+    guard let one = arguments[1] as? IntegerLiteralInst,
+          let oneValue = one.value,
+          oneValue == -1,
+          let lhsBuiltin = arguments[0] as? BuiltinInst,
+          lhsBuiltin.type.isBuiltinInteger,
+          let negatedBuiltinName = lhsBuiltin.negatedComparisonBuiltinName
+    else {
+      return
+    }
+
+    let builder = Builder(before: lhsBuiltin, context)
+    let negated = builder.createBuiltinBinaryFunction(name: negatedBuiltinName,
+        operandType: lhsBuiltin.arguments[0].type,
+        resultType: lhsBuiltin.type,
+        arguments: Array(lhsBuiltin.arguments))
+    self.replace(with: negated, context)
+  }
+
+  private var negatedComparisonBuiltinName: String? {
+    switch id {
+    case .ICMP_EQ:  return "cmp_ne"
+    case .ICMP_NE:  return "cmp_eq"
+    case .ICMP_SLE: return "cmp_sgt"
+    case .ICMP_SLT: return "cmp_sge"
+    case .ICMP_SGE: return "cmp_slt"
+    case .ICMP_SGT: return "cmp_sle"
+    case .ICMP_ULE: return "cmp_ugt"
+    case .ICMP_ULT: return "cmp_uge"
+    case .ICMP_UGE: return "cmp_ult"
+    case .ICMP_UGT: return "cmp_ule"
+    default:
+      return nil
+    }
+  }
 }
 
 private extension Value {
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCheckedCast.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCheckedCast.swift
index fe922951bdac0..b7f45bf361351 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCheckedCast.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCheckedCast.swift
@@ -81,7 +81,9 @@ private extension UnconditionalCheckedCastInst {
       return
     }
     let conformance = sourceFormalType.instanceTypeOfMetatype.checkConformance(to: proto)
-    guard conformance.isValid else {
+    guard conformance.isValid,
+          conformance.matchesActorIsolation(in: parentFunction)
+    else {
       return
     }
     
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyClassifyBridgeObject.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyClassifyBridgeObject.swift
index ffe232bfb19bf..4232aba270ef8 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyClassifyBridgeObject.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyClassifyBridgeObject.swift
@@ -23,7 +23,7 @@ extension ClassifyBridgeObjectInst : OnoneSimplifiable, SILCombineSimplifiable {
     }
 
     let builder = Builder(before: self, context)
-    let falseLiteral = builder.createIntegerLiteral(0, type: context.getBuiltinIntegerType(bitWidth: 1))
+    let falseLiteral = builder.createBoolLiteral(false)
     let tp = builder.createTuple(type: self.type, elements: [falseLiteral, falseLiteral])
     uses.replaceAll(with: tp, context)
     context.erase(instruction: self)
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCondBranch.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCondBranch.swift
index 222c07badadbb..08af5d25b6241 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCondBranch.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCondBranch.swift
@@ -27,9 +27,9 @@ private extension CondBranchInst {
     }
     let builder = Builder(before: self, context)
     if conditionValue == 0 {
-      builder.createBranch(to: falseBlock, arguments: Array(falseOperands.map { $0.value }))
+      builder.createBranch(to: falseBlock, arguments: Array(falseOperands.values))
     } else {
-      builder.createBranch(to: trueBlock, arguments: Array(trueOperands.map { $0.value }))
+      builder.createBranch(to: trueBlock, arguments: Array(trueOperands.values))
     }
     context.erase(instruction: self)
   }
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCopyBlock.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCopyBlock.swift
new file mode 100644
index 0000000000000..ecc0e635300be
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyCopyBlock.swift
@@ -0,0 +1,107 @@
+//===--- SimplifyCopyBlock.swift ------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+
+extension CopyBlockInst : Simplifiable, SILCombineSimplifiable {
+
+  /// Removes a `copy_block` if its only uses, beside ownership instructions, are callees of function calls
+  /// ```
+  ///   %2 = copy_block %0
+  ///   %3 = begin_borrow [lexical] %2
+  ///   %4 = apply %3() : $@convention(block) @noescape () -> ()
+  ///   end_borrow %3
+  ///   destroy_value %2
+  /// ```
+  /// ->
+  /// ```
+  ///   %4 = apply %0() : $@convention(block) @noescape () -> ()
+  /// ```
+  ///
+  func simplify(_ context: SimplifyContext) {
+    if hasValidUses(block: self) {
+      replaceBlock(self, with: operand.value, context)
+      context.erase(instruction: self)
+    }
+  }
+}
+
+private func hasValidUses(block: Value) -> Bool {
+  for use in block.uses {
+    switch use.instruction {
+    case let beginBorrow as BeginBorrowInst:
+      if !hasValidUses(block: beginBorrow) {
+        return false
+      }
+    case let apply as FullApplySite where apply.isCallee(operand: use):
+      break
+    case let partialApply as PartialApplyInst:
+      // If the block is passed to another function - either as closure argument or as closure capture -
+      // it's "converted" to a swift closure with the help of a thunk. The thunk just calls the block.
+      // If this is a non-escaping partial_apply and it's such a thunk, the block does not escape.
+      if partialApply.canClosureArgumentEscape(closure: use) {
+        return false
+      }
+    case is EndBorrowInst, is DestroyValueInst:
+      break
+    default:
+      return false
+    }
+  }
+  return true
+}
+
+private func replaceBlock(_ block: Value, with original: Value, _ context: SimplifyContext) {
+  for use in block.uses {
+    switch use.instruction {
+    case let beginBorrow as BeginBorrowInst:
+      replaceBlock(beginBorrow, with: original, context)
+      context.erase(instruction: beginBorrow)
+    case is FullApplySite:
+      use.set(to: original, context)
+    case let partialApply as PartialApplyInst:
+      if original.ownership == .unowned {
+        let builder = Builder(before: partialApply, context)
+        let conv = builder.createUncheckedOwnershipConversion(operand: original, resultOwnership: .guaranteed)
+        use.set(to: conv, context)
+      } else {
+        use.set(to: original, context)
+      }
+    case is EndBorrowInst, is DestroyValueInst:
+      context.erase(instruction: use.instruction)
+    default:
+      fatalError("unhandled use")
+    }
+  }
+}
+
+private extension PartialApplyInst {
+  func canClosureArgumentEscape(closure: Operand) -> Bool {
+    guard isOnStack,
+          let callee = referencedFunction,
+          callee.isDefinition,
+          let calleeArg = calleeArgument(of: closure, in: callee),
+          // If the callee only _calls_ the closure argument, it does not escape.
+          calleeArg.uses.allSatisfy(isCalleeOperandOfApply)
+    else {
+      return true
+    }
+    return false
+  }
+}
+
+private func isCalleeOperandOfApply(_ operand: Operand) -> Bool {
+  if let apply = operand.instruction as? FullApplySite, apply.isCallee(operand: operand) {
+    return true
+  }
+  return false
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyEndCOWMutationAddr.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyEndCOWMutationAddr.swift
new file mode 100644
index 0000000000000..b68aba70fc5bc
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyEndCOWMutationAddr.swift
@@ -0,0 +1,32 @@
+//===--- SimplifyEndCOWMutationAddr.swift ---------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+
+// Simplify end_cow_mutation_addr to end_cow_mutation when it's operand is loadable
+extension EndCOWMutationAddrInst: OnoneSimplifiable, SILCombineSimplifiable {
+  func simplify(_ context: SimplifyContext) {
+    let address = operand.value
+    if !address.type.isLoadable(in: parentFunction) {
+      return
+    }
+    if address.type.isTrivial(in: parentFunction) {
+      context.erase(instruction: self)
+      return
+    }
+    let builder = Builder(before: self, context)
+    let load = builder.createLoad(fromAddress: address, ownership: parentFunction.hasOwnership ? .take : .unqualified)
+    let endCOWMutation = builder.createEndCOWMutation(instance: load, keepUnique: false) 
+    builder.createStore(source: endCOWMutation, destination: address, ownership: parentFunction.hasOwnership ? .initialize : .unqualified)
+    context.erase(instruction: self)
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyExplicitCopy.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyExplicitCopy.swift
new file mode 100644
index 0000000000000..3afabf24f7754
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyExplicitCopy.swift
@@ -0,0 +1,64 @@
+//===--- SimplifyExplicitCopy.swift ---------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+
+// The `explicit_copy_value` and `explicit_copy_addr` instructions are only used for non-copyable
+// diagnostics in the mandatory pipeline. After that we can replace them by their non-explicit counterparts
+// so that optimizations (which only know of `copy_value` and `copy_addr`) can do their work.
+
+/// Replaces
+///
+/// ```
+///   %1 = explicit_copy_value %0
+/// ```
+/// ->
+/// ```
+///   %1 = copy_value %0
+/// ```
+///
+extension ExplicitCopyValueInst : Simplifiable, SILCombineSimplifiable {
+  func simplify(_ context: SimplifyContext) {
+    if context.silStage == .raw {
+      // Make sure we don't remove `explicit_copy_value` in the diagnostic pipeline.
+      return
+    }
+
+    let builder = Builder(before: self, context)
+    let copyValue = builder.createCopyValue(operand: fromValue)
+    replace(with: copyValue, context)
+  }
+}
+
+/// Replaces
+///
+/// ```
+///   explicit_copy_addr %0 to %1
+/// ```
+/// ->
+/// ```
+///   copy_addr %0 to %1
+/// ```
+///
+extension ExplicitCopyAddrInst : Simplifiable, SILCombineSimplifiable {
+  func simplify(_ context: SimplifyContext) {
+    if context.silStage == .raw {
+      // Make sure we don't remove `explicit_copy_addr` in the diagnostic pipeline.
+      return
+    }
+
+    let builder = Builder(before: self, context)
+    builder.createCopyAddr(from: source, to: destination,
+                           takeSource: isTakeOfSource, initializeDest: isInitializationOfDestination)
+    context.erase(instruction: self)
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyLoad.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyLoad.swift
index 40409265b6430..93c93ca6d94b2 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyLoad.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyLoad.swift
@@ -75,7 +75,7 @@ extension LoadInst : OnoneSimplifiable, SILCombineSimplifiable {
        index < stringLiteral.value.count {
 
       let builder = Builder(before: self, context)
-      let charLiteral = builder.createIntegerLiteral(Int(stringLiteral.value[index]), type: type)
+      let charLiteral = builder.createIntegerLiteral(stringLiteral.value[index], type: type)
       uses.replaceAll(with: charLiteral, context)
       context.erase(instruction: self)
       return true
@@ -104,10 +104,10 @@ extension LoadInst : OnoneSimplifiable, SILCombineSimplifiable {
     if !globalInitVal.canBeCopied(into: parentFunction, context) {
       return false
     }
-    var cloner = StaticInitCloner(cloneBefore: self, context)
+    var cloner = Cloner(cloneBefore: self, context)
     defer { cloner.deinitialize() }
 
-    let initVal = cloner.clone(globalInitVal)
+    let initVal = cloner.cloneRecursively(globalInitValue: globalInitVal)
 
     uses.replaceAll(with: initVal, context)
     // Also erases a builtin "once" on which the global_addr depends on. This is fine
@@ -323,7 +323,7 @@ private extension Value {
         return false
       }
       if let fri = value as? FunctionRefInst {
-        if function.isAnySerialized, 
+        if function.isAnySerialized,
            !fri.referencedFunction.hasValidLinkageForFragileRef(function.serializedKind)
         {
           return false
@@ -376,3 +376,74 @@ private extension Instruction {
     return shiftValue > 0
   }
 }
+
+/// Analyses the global initializer function and returns the `alloc_global` and `store`
+/// instructions which initialize the global.
+/// Returns nil if `function` has any side-effects beside initializing the global.
+///
+/// The function's single basic block must contain following code pattern:
+/// ```
+///   alloc_global @the_global
+///   %a = global_addr @the_global
+///   %i = some_const_initializer_insts
+///   store %i to %a
+/// ```
+///
+/// For all other instructions `handleUnknownInstruction` is called and such an instruction
+/// is accepted if `handleUnknownInstruction` returns true.
+private func getGlobalInitialization(
+  of function: Function,
+  _ context: some Context,
+  handleUnknownInstruction: (Instruction) -> Bool
+) -> (allocInst: AllocGlobalInst, storeToGlobal: StoreInst)? {
+  guard let block = function.blocks.singleElement else {
+    return nil
+  }
+
+  var allocInst: AllocGlobalInst? = nil
+  var globalAddr: GlobalAddrInst? = nil
+  var store: StoreInst? = nil
+
+  for inst in block.instructions {
+    switch inst {
+    case is ReturnInst,
+         is DebugValueInst,
+         is DebugStepInst,
+         is BeginAccessInst,
+         is EndAccessInst:
+      continue
+    case let agi as AllocGlobalInst:
+      if allocInst == nil {
+        allocInst = agi
+        continue
+      }
+    case let ga as GlobalAddrInst:
+      if let agi = allocInst, agi.global == ga.global {
+        globalAddr = ga
+      }
+      continue
+    case let si as StoreInst:
+      if store == nil,
+         let ga = globalAddr,
+         si.destination == ga
+      {
+        store = si
+        continue
+      }
+    // Note that the initializer must not contain a `global_value` because `global_value` needs to
+    // initialize the class metadata at runtime.
+    default:
+      if inst.isValidInStaticInitializerOfGlobal(context) {
+        continue
+      }
+    }
+    if handleUnknownInstruction(inst) {
+      continue
+    }
+    return nil
+  }
+  if let store = store {
+    return (allocInst: allocInst!, storeToGlobal: store)
+  }
+  return nil
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyMarkDependence.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyMarkDependence.swift
new file mode 100644
index 0000000000000..8d4ecc52daf43
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyMarkDependence.swift
@@ -0,0 +1,116 @@
+//===--- SimplifyMarkDependence.swift -------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+
+// Note: this simplification cannot run before dependency diagnostics.
+// See `var isRedundant` below.
+
+extension MarkDependenceInst : OnoneSimplifiable, SILCombineSimplifiable {
+  func simplify(_ context: SimplifyContext) {
+    if isRedundant ||
+       // A literal lives forever, so no mark_dependence is needed.
+       // This pattern can occur after StringOptimization when a utf8CString of a literal is replaced
+       // by the string_literal itself.
+       value.isLiteral
+    {
+      replace(with: value, context)
+      return
+    }
+    simplifyBaseOperand(context)
+  }
+}
+
+extension MarkDependenceAddrInst : OnoneSimplifiable, SILCombineSimplifiable {
+  func simplify(_ context: SimplifyContext) {
+    if isRedundant {
+      context.erase(instruction: self)
+      return
+    }
+    simplifyBaseOperand(context)
+  }
+}
+
+private extension MarkDependenceInstruction {
+  var isRedundant: Bool {
+    if base.type.isObject && base.type.isTrivial(in: base.parentFunction)
+         && !(base.definingInstruction is BeginApplyInst) {
+      // Sometimes due to specialization/builtins, we can get a mark_dependence whose base is a trivial
+      // typed object. Trivial values live forever. Therefore the mark_dependence does not have a meaning.
+      // begin_apply is a special case. A dependency on the token is limited to the coroutine scope (ideally, the token
+      // would have a non-trivial type like $Builtin.Token).
+      //
+      // Note: the mark_dependence is still needed for lifetime diagnostics. So it's important that this
+      //       simplification does not run before the lifetime diagnostic pass.
+      return true
+    }
+    // If the value is an address projection from the base the mark_dependence is not needed because the
+    // base cannot be destroyed before the accessing the value, anyway.
+    if valueOrAddress.type.isAddress, base.type.isAddress,
+       // But we still need to keep the mark_dependence for non-escapable types because a non-escapable
+       // value can be copied and copies must not outlive the base.
+       valueOrAddress.type.isEscapable(in: parentFunction),
+       base.accessPath.isEqualOrContains(valueOrAddress.accessPath)
+    {
+      return true
+    }
+    return false
+  }
+
+  func simplifyBaseOperand(_ context: SimplifyContext) {
+    /// In OSSA, the `base` is a borrow introducing operand. It is pretty complicated to change the base.
+    /// So, for simplicity, we only do this optimization when OSSA is already lowered.
+    if parentFunction.hasOwnership {
+      return
+    }
+    // Replace the base operand with the operand of the base value if it's a certain kind of forwarding
+    // instruction.
+    let rootBase = base.lookThroughEnumAndExistentialRef
+    if rootBase != base {
+      baseOperand.set(to: rootBase, context)
+    }
+  }
+}
+
+private extension Value {
+  /// True, if this is a literal instruction or a struct of a literal instruction.
+  /// What we want to catch here is a `UnsafePointer<Int8>` of a string literal.
+  var isLiteral: Bool {
+    switch self {
+    case let s as StructInst:
+      if let singleOperand = s.operands.singleElement {
+        return singleOperand.value.isLiteral
+      }
+      return false
+    case  is IntegerLiteralInst, is FloatLiteralInst, is StringLiteralInst:
+      return true
+    default:
+      return false
+    }
+  }
+
+  var lookThroughEnumAndExistentialRef: Value {
+    switch self {
+    case let e as EnumInst:
+      if let payload = e.payload {
+        return payload.lookThroughEnumAndExistentialRef
+      }
+      return self
+    case let ier as InitExistentialRefInst:
+      return ier.instance.lookThroughEnumAndExistentialRef
+    case let oer as OpenExistentialRefInst:
+      return oer.existential.lookThroughEnumAndExistentialRef
+    default:
+      return self
+    }
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyMisc.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyMisc.swift
index 2aaaaeb80435d..2f571a61768c6 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyMisc.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyMisc.swift
@@ -15,7 +15,7 @@ import SIL
 extension TypeValueInst: OnoneSimplifiable, SILCombineSimplifiable {
   func simplify(_ context: SimplifyContext) {
     // If our parameter is not known statically, then bail.
-    guard paramType.isInteger else {
+    guard let value = value else {
       return
     }
 
@@ -30,3 +30,4 @@ extension TypeValueInst: OnoneSimplifiable, SILCombineSimplifiable {
     context.erase(instruction: self)
   }
 }
+
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyPointerToAddress.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyPointerToAddress.swift
index 0b2e8fde0fc10..e937659faa986 100644
--- a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyPointerToAddress.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyPointerToAddress.swift
@@ -69,7 +69,7 @@ private func removeAddressToPointerToAddressPair(
 ///
 private func simplifyIndexRawPointer(of ptr2Addr: PointerToAddressInst, _ context: SimplifyContext) -> Bool {
   guard let indexRawPtr = ptr2Addr.pointer as? IndexRawPointerInst,
-        let tupleExtract = indexRawPtr.index.lookThroughTruncOrBitCast as? TupleExtractInst,
+        let tupleExtract = indexRawPtr.index.lookThroughIndexScalarCast as? TupleExtractInst,
         let strideMul = tupleExtract.tuple as? BuiltinInst, strideMul.id == .SMulOver,
         let (index, strideType) = strideMul.indexAndStrideOfMultiplication,
         strideType == ptr2Addr.type.objectType
@@ -293,13 +293,6 @@ private extension Value {
       return self
     }
   }
-
-  var lookThroughTruncOrBitCast: Value {
-    if let truncOrBitCast = self as? BuiltinInst, truncOrBitCast.id == .TruncOrBitCast {
-      return truncOrBitCast.arguments[0]
-    }
-    return self
-  }
 }
 
 private extension BuiltinInst {
@@ -321,9 +314,9 @@ private extension BuiltinInst {
 
 private extension Builder {
   func createCastIfNeeded(of index: Value, toIndexTypeOf indexRawPtr: IndexRawPointerInst) -> Value {
-    if let truncOrBitCast = indexRawPtr.index as? BuiltinInst {
-      assert(truncOrBitCast.id == .TruncOrBitCast)
-      return createBuiltin(name: truncOrBitCast.name, type: truncOrBitCast.type, arguments: [index])
+    if let cast = indexRawPtr.index as? BuiltinInst {
+      assert(cast.id == .TruncOrBitCast || cast.id == .SExtOrBitCast)
+      return createBuiltin(name: cast.name, type: cast.type, arguments: [index])
     }
     return index
   }
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyStruct.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyStruct.swift
new file mode 100644
index 0000000000000..90071e604af8f
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyStruct.swift
@@ -0,0 +1,112 @@
+//===--- SimplifyStruct.swift ---------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+
+extension StructInst : Simplifiable, SILCombineSimplifiable {
+
+  /// Eliminates `struct_extract`s of an owned `struct` where the `struct_extract`s are inside a
+  /// a borrow scope.
+  /// This is done by splitting the `begin_borrow` of the whole struct into individual borrows of the fields
+  /// (for trivial fields no borrow is needed). And then sinking the `struct` to it's consuming use(s).
+  ///
+  /// ```
+  ///   %3 = struct $S(%nonTrivialField, %trivialField)  // owned
+  ///   ...
+  ///   %4 = begin_borrow %3
+  ///   %5 = struct_extract %4, #S.nonTrivialField
+  ///   %6 = struct_extract %4, #S.trivialField
+  ///   use %5, %6
+  ///   end_borrow %4
+  ///   ...
+  ///   end_of_lifetime %3
+  /// ```
+  /// ->
+  /// ```
+  ///   ...
+  ///   %5 = begin_borrow %nonTrivialField
+  ///   use %5, %trivialField
+  ///   end_borrow %5
+  ///   ...
+  ///   %3 = struct $S(%nonTrivialField, %trivialField)
+  ///   end_of_lifetime %3
+  /// ```
+  func simplify(_ context: SimplifyContext) {
+    guard ownership == .owned,
+          hasOnlyStructExtractUsesInBorrowScopes()
+    else {
+      return
+    }
+
+    for beginBorrow in uses.users(ofType: BeginBorrowInst.self) {
+      splitAndRemoveStructExtracts(beginBorrow: beginBorrow, context)
+    }
+
+    self.sinkToEndOfLifetime(context)
+
+    context.erase(instructionIncludingAllUsers: self)
+  }
+
+  private func hasOnlyStructExtractUsesInBorrowScopes() -> Bool {
+    var hasStructExtract = false
+
+    for use in uses.ignoreDebugUses {
+      switch use.instruction {
+      case let beginBorrow as BeginBorrowInst:
+        for borrowUse in beginBorrow.uses.ignoreDebugUses {
+          switch borrowUse.instruction {
+          case is EndBorrowInst:
+            break
+          case is StructExtractInst:
+            hasStructExtract = true
+          default:
+            return false
+          }
+        }
+      default:
+        guard use.endsLifetime else {
+          return false
+        }
+      }
+    }
+    return hasStructExtract
+  }
+
+  private func splitAndRemoveStructExtracts(beginBorrow: BeginBorrowInst, _ context: SimplifyContext) {
+    for structExtract in beginBorrow.uses.users(ofType: StructExtractInst.self) {
+      let field = self.operands[structExtract.fieldIndex].value
+      switch structExtract.ownership {
+      case .none:
+        structExtract.replace(with: field, context)
+      case .guaranteed:
+        let beginBuilder = Builder(before: beginBorrow, context)
+        let borrowedField = beginBuilder.createBeginBorrow(of: field,
+                                                           isLexical: beginBorrow.isLexical,
+                                                           hasPointerEscape: beginBorrow.hasPointerEscape)
+        structExtract.replace(with: borrowedField, context)
+        for endBorrow in beginBorrow.endInstructions {
+          let endBuilder = Builder(before: endBorrow, context)
+          endBuilder.createEndBorrow(of: borrowedField)
+        }
+      case .owned, .unowned:
+        fatalError("wrong ownership of struct_extract")
+      }
+    }
+  }
+  private func sinkToEndOfLifetime(_ context: SimplifyContext) {
+    for use in uses where use.endsLifetime {
+      let builder = Builder(before: use.instruction, context)
+      let delayedStruct = builder.createStruct(type: type, elements: Array(operands.values))
+      use.set(to: delayedStruct, context)
+    }
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyUncheckedAddrCast.swift b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyUncheckedAddrCast.swift
new file mode 100644
index 0000000000000..d8455d555aef8
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyUncheckedAddrCast.swift
@@ -0,0 +1,81 @@
+//===--- SimplifyUncheckedAddrCast.swift ----------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+
+extension UncheckedAddrCastInst : OnoneSimplifiable, SILCombineSimplifiable {
+
+  func simplify(_ context: SimplifyContext) {
+    // ```
+    //   %1 = unchecked_addr_cast %0 : $*T to $*T
+    // ```
+    // ->
+    //   replace %1 with %0
+    //
+    if optimizeSameTypeCast(context) {
+      return
+    }
+
+    // ```
+    //   %1 = unchecked_addr_cast %0 : $*U to $*V
+    //   %2 = unchecked_addr_cast %1 : $*V to $*T
+    // ```
+    // ->
+    // ```
+    //   %2 = unchecked_addr_cast %0: $*U to $*T
+    // ```
+    if optimizeDoubleCast(context) {
+      return
+    }
+
+    // ```
+    //   %1 = unchecked_addr_cast %0 : $*Builtin.FixedArray<N, Element> to $*Element
+    // ```
+    // ->
+    // ```
+    //   %1 = vector_base_addr %0 : $*Builtin.FixedArray<N, Element>
+    // ```
+    _ = optimizeVectorBaseCast(context)
+  }
+}
+
+private extension UncheckedAddrCastInst {
+  func optimizeSameTypeCast(_ context: SimplifyContext) -> Bool {
+    if fromAddress.type == type {
+      self.replace(with: fromAddress, context)
+      return true
+    }
+    return false
+  }
+
+  func optimizeDoubleCast(_ context: SimplifyContext) -> Bool {
+    if let firstCast = fromAddress as? UncheckedAddrCastInst {
+      let builder = Builder(before: self, context)
+      let newCast = builder.createUncheckedAddrCast(from: firstCast.fromAddress, to: type)
+      self.replace(with: newCast, context)
+      return true
+    }
+    return false
+  }
+
+  func optimizeVectorBaseCast(_ context: SimplifyContext) -> Bool {
+    if fromAddress.type.isBuiltinFixedArray,
+       fromAddress.type.builtinFixedArrayElementType(in: parentFunction, maximallyAbstracted: true).addressType == type
+    {
+      let builder = Builder(before: self, context)
+      let vectorBase = builder.createVectorBaseAddr(vector: fromAddress)
+      self.replace(with: vectorBase, context)
+      return true
+    }
+    return false
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/ModulePasses/CMakeLists.txt b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/CMakeLists.txt
index df7a020d3024e..5ad26d798bc0a 100644
--- a/SwiftCompilerSources/Sources/Optimizer/ModulePasses/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/CMakeLists.txt
@@ -8,6 +8,7 @@
 
 swift_compiler_sources(Optimizer
   DiagnoseUnknownConstValues.swift
+  EmbeddedSwiftDiagnostics.swift
   MandatoryPerformanceOptimizations.swift
   ReadOnlyGlobalVariables.swift
   StackProtection.swift
diff --git a/SwiftCompilerSources/Sources/Optimizer/ModulePasses/DiagnoseUnknownConstValues.swift b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/DiagnoseUnknownConstValues.swift
index b33dccdb1c865..caf6f145555c0 100644
--- a/SwiftCompilerSources/Sources/Optimizer/ModulePasses/DiagnoseUnknownConstValues.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/DiagnoseUnknownConstValues.swift
@@ -39,8 +39,8 @@ let diagnoseUnknownConstValues = ModulePass(name: "diagnose-unknown-const-values
 private func verifyGlobals(_ context: ModulePassContext) {
   for gv in context.globalVariables where gv.isConst {
     if gv.staticInitValue == nil {
-      context.diagnosticEngine.diagnose(gv.varDecl?.location.sourceLoc,
-                                        .require_const_initializer_for_const)
+      context.diagnosticEngine.diagnose(.require_const_initializer_for_const,
+                                        at: gv.varDecl?.location.sourceLoc)
     }
   }
 }
@@ -66,8 +66,8 @@ private func verifyLocal(debugValueInst: DebugValueInst,
   }
   
   if !constExprState.isConstantValue(debugValueInst.operand.value) {
-    context.diagnosticEngine.diagnose(debugValueInst.location.sourceLoc,
-                                      .require_const_initializer_for_const)
+    context.diagnosticEngine.diagnose(.require_const_initializer_for_const,
+                                      at: debugValueInst.location)
   }
 }
 
@@ -92,8 +92,8 @@ private func verifyCallArguments(apply: FullApplySite,
   for (paramIdx, param) in calleeFn.convention.parameters.enumerated() where param.hasOption(.const) {
     let matchingOperand = apply.parameterOperands[paramIdx]
     if !constExprState.isConstantValue(matchingOperand.value) {
-      context.diagnosticEngine.diagnose(apply.location.sourceLoc,
-                                        .require_const_arg_for_parameter)
+      context.diagnosticEngine.diagnose(.require_const_arg_for_parameter,
+                                        at: apply.location)
     }
   }
 }
diff --git a/SwiftCompilerSources/Sources/Optimizer/ModulePasses/EmbeddedSwiftDiagnostics.swift b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/EmbeddedSwiftDiagnostics.swift
new file mode 100644
index 0000000000000..4d99ca22ac7ba
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/EmbeddedSwiftDiagnostics.swift
@@ -0,0 +1,408 @@
+//===--- EmbeddedSwiftDiagnostics.swift -----------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import AST
+import SIL
+
+/// Diagnoses violations of Embedded Swift language restrictions.
+///
+let embeddedSwiftDiagnostics = ModulePass(name: "embedded-swift-diagnostics") {
+  (moduleContext: ModulePassContext) in
+
+  guard moduleContext.options.enableEmbeddedSwift,
+        // Skip all embedded diagnostics if asked. This is used from SourceKit to avoid reporting
+        // false positives when WMO is turned off for indexing purposes.
+        moduleContext.enableWMORequiredDiagnostics
+  else {
+    return
+  }
+
+  // Try to start with public and exported functions to get better caller information in the diagnostics.
+  let allFunctions = Array(moduleContext.functions.lazy.filter { !$0.isGeneric })
+                       .sorted(by: { $0.priority < $1.priority })
+
+  var checker = FunctionChecker(moduleContext)
+  defer { checker.deinitialize() }
+
+  for function in allFunctions {
+    do {
+      assert(checker.callStack.isEmpty)
+      try checker.checkFunction(function)
+    } catch let error as Diagnostic<Location> {
+      checker.diagnose(error)
+    } catch {
+      fatalError("unknown error thrown")
+    }
+  }
+
+  checkVTables(moduleContext)
+}
+
+private struct FunctionChecker {
+  let context: ModulePassContext
+  var visitedFunctions = Set<Function>()
+  var visitedConformances = Set<Conformance>()
+  var callStack: Stack<CallSite>
+
+  init(_ context: ModulePassContext) {
+    self.context = context
+    self.callStack = Stack(context)
+  }
+
+  mutating func deinitialize() {
+    callStack.deinitialize()
+  }
+
+  mutating func checkFunction(_ function: Function) throws {
+    guard function.isDefinition,
+          // Avoid infinite recursion
+          visitedFunctions.insert(function).inserted
+    else {
+      return
+    }
+
+    for inst in function.instructions {
+      try checkInstruction(inst)
+    }
+  }
+
+  mutating func checkInstruction(_ instruction: Instruction) throws {
+    switch instruction {
+    case is OpenExistentialMetatypeInst,
+         is InitExistentialMetatypeInst:
+      throw Diagnostic(.embedded_swift_metatype_type, instruction.operands[0].value.type, at: instruction.location)
+
+    case is OpenExistentialBoxInst,
+         is OpenExistentialBoxValueInst,
+         is OpenExistentialValueInst,
+         is OpenExistentialAddrInst,
+         is InitExistentialAddrInst,
+         is InitExistentialValueInst,
+         is ExistentialMetatypeInst:
+      throw Diagnostic(.embedded_swift_existential_type, instruction.operands[0].value.type, at: instruction.location)
+
+    case let aeb as AllocExistentialBoxInst:
+      throw Diagnostic(.embedded_swift_existential_type, aeb.type, at: instruction.location)
+
+    case let ier as InitExistentialRefInst:
+      for conf in ier.conformances {
+        try checkConformance(conf, location: ier.location)
+      }
+
+    case is ValueMetatypeInst,
+         is MetatypeInst:
+      let metaType = (instruction as! SingleValueInstruction).type
+      if metaType.representationOfMetatype != .thin {
+        let rawType = metaType.canonicalType.rawType.instanceTypeOfMetatype
+        let type = rawType.isDynamicSelf ? rawType.staticTypeOfDynamicSelf : rawType
+        if !type.isClass {
+          throw Diagnostic(.embedded_swift_metatype_type, type, at: instruction.location)
+        }
+      }
+
+    case is KeyPathInst:
+      throw Diagnostic(.embedded_swift_keypath, at: instruction.location)
+
+    case is CheckedCastAddrBranchInst,
+         is UnconditionalCheckedCastAddrInst:
+      throw Diagnostic(.embedded_swift_dynamic_cast, at: instruction.location)
+
+    case let abi as AllocBoxInst:
+      // It needs a bit of work to support alloc_box of generic non-copyable structs/enums with deinit,
+      // because we need to specialize the deinit functions, though they are not explicitly referenced in SIL.
+      // Until this is supported, give an error in such cases. Otherwise IRGen would crash.
+      if abi.allocsGenericValueTypeWithDeinit {
+        throw Diagnostic(.embedded_capture_of_generic_value_with_deinit, at: abi.location)
+      }
+      fallthrough
+    case is AllocRefInst,
+         is AllocRefDynamicInst:
+      if context.options.noAllocations {
+        throw Diagnostic(.embedded_swift_allocating_type, (instruction as! SingleValueInstruction).type,
+                              at: instruction.location)
+      }
+
+    case is ThunkInst:
+      if context.options.noAllocations {
+        throw Diagnostic(.embedded_swift_allocating, at: instruction.location)
+      }
+
+    case let ba as BeginApplyInst:
+      if context.options.noAllocations {
+        throw Diagnostic(.embedded_swift_allocating_coroutine, at: instruction.location)
+      }
+      try checkApply(apply: ba)
+
+    case let pai as PartialApplyInst:
+      if context.options.noAllocations && !pai.isOnStack {
+        throw Diagnostic(.embedded_swift_allocating_closure, at: instruction.location)
+      }
+      try checkApply(apply: pai)
+
+    // Remaining apply instructions
+    case let apply as ApplySite:
+      try checkApply(apply: apply)
+
+    case let bi as BuiltinInst:
+      switch bi.id {
+      case .AllocRaw:
+        if context.options.noAllocations {
+          throw Diagnostic(.embedded_swift_allocating, at: instruction.location)
+        }
+      case .BuildOrdinaryTaskExecutorRef,
+           .BuildOrdinarySerialExecutorRef,
+           .BuildComplexEqualitySerialExecutorRef:
+        // Those builtins implicitly create an existential.
+        try checkConformance(bi.substitutionMap.conformances[0], location: bi.location)
+
+      default:
+        break
+      }
+
+    default:
+      break
+    }
+  }
+
+  mutating func checkApply(apply: ApplySite) throws {
+    if context.options.noAllocations && apply.isAsync {
+      throw Diagnostic(.embedded_swift_allocating_type, at: apply.location)
+    }
+
+    if !apply.callee.type.hasValidSignatureForEmbedded,
+       // Some runtime functions have generic parameters in SIL, which are not used in IRGen.
+       // Therefore exclude runtime functions at all.
+       !apply.callsEmbeddedRuntimeFunction
+    {
+      switch apply.callee {
+      case let cmi as ClassMethodInst:
+        throw Diagnostic(.embedded_cannot_specialize_class_method, cmi.member, at: apply.location)
+      case let wmi as WitnessMethodInst:
+        throw Diagnostic(.embedded_cannot_specialize_witness_method, wmi.member, at: apply.location)
+      default:
+        if apply.substitutionMap.replacementTypes.contains(where: { $0.hasDynamicSelf }),
+           apply.calleeHasGenericSelfMetatypeParameter
+        {
+          throw Diagnostic(.embedded_call_generic_function_with_dynamic_self, at: apply.location)
+        }
+        throw Diagnostic(.embedded_call_generic_function, at: apply.location)
+      }
+    }
+
+    // Although all (non-generic) functions are initially put into the worklist there are two reasons
+    // to call `checkFunction` recursively:
+    // * To get a better caller info in the diagnostics.
+    // * When passing an opened existential to a generic function, it's valid in Embedded swift even if the
+    //   generic is not specialized. We need to check such generic functions, too.
+    if let callee = apply.referencedFunction {
+      callStack.push(CallSite(apply: apply, callee: callee))
+      try checkFunction(callee)
+      _ = callStack.pop()
+    }
+  }
+
+  // Check for any violations in witness tables for existentials.
+  mutating func checkConformance(_ conformance: Conformance, location: Location) throws {
+    guard conformance.isConcrete,
+          // Avoid infinite recursion
+          visitedConformances.insert(conformance).inserted,
+          let witnessTable = context.lookupWitnessTable(for: conformance)
+    else {
+      return
+    }
+    if !conformance.protocol.requiresClass {
+      throw Diagnostic(.embedded_swift_existential_protocol, conformance.protocol.name, at: location)
+    }
+
+    for entry in witnessTable.entries {
+      switch entry {
+      case .invalid, .associatedType:
+        break
+      case .method(let requirement, let witness):
+        if let witness = witness {
+          callStack.push(CallSite(location: location, kind: .conformance))
+          if witness.isGeneric {
+            throw Diagnostic(.embedded_cannot_specialize_witness_method, requirement, at: witness.location)
+          }
+          try checkFunction(witness)
+          _ = callStack.pop()
+        }
+      case .baseProtocol(_, let witness):
+        try checkConformance(witness, location: location)
+      case .associatedConformance(_, let assocConf):
+        // If it's not a class protocol, the associated type can never be used to create
+        // an existential. Therefore this witness entry is never used at runtime in embedded swift.
+        if assocConf.protocol.requiresClass {
+          try checkConformance(assocConf, location: location)
+        }
+      }
+    }
+  }
+
+  mutating func diagnose(_ error: Diagnostic<Location>) {
+    var diagPrinted = false
+    if error.location.hasValidLineNumber {
+      context.diagnosticEngine.diagnose(error)
+      diagPrinted = true
+    }
+
+    // If the original instruction doesn't have a location (e.g. because it's in a stdlib function),
+    // search the callstack and use the location from a call site.
+    while let callSite = callStack.pop() {
+      if !diagPrinted {
+        if callSite.location.hasValidLineNumber {
+          context.diagnosticEngine.diagnose(error.id, error.arguments, at: callSite.location)
+          diagPrinted = true
+        }
+      } else {
+        // Print useful callsite information as a note (see `CallSite`)
+        switch callSite.kind {
+        case .constructorCall:
+          context.diagnosticEngine.diagnose(.embedded_constructor_called, at: callSite.location)
+        case .specializedCall:
+          context.diagnosticEngine.diagnose(.embedded_specialization_called_from, at: callSite.location)
+        case .conformance:
+          context.diagnosticEngine.diagnose(.embedded_existential_created, at: callSite.location)
+        case .call:
+          break
+        }
+      }
+    }
+    if !diagPrinted {
+      context.diagnosticEngine.diagnose(error)
+    }
+  }
+}
+
+// Print errors for generic functions in vtables, which is not allowed in embedded Swift.
+private func checkVTables(_ context: ModulePassContext) {
+  for vTable in context.vTables {
+    if !vTable.class.isGenericAtAnyLevel || vTable.isSpecialized {
+      for entry in vTable.entries where entry.implementation.isGeneric {
+        context.diagnosticEngine.diagnose(.embedded_cannot_specialize_class_method, entry.methodDecl,
+                                          at: entry.methodDecl.location)
+      }
+    }
+  }
+}
+
+/// Relevant call site information for diagnostics.
+/// This information is printed as additional note(s) after the original diagnostic.
+private struct CallSite {
+  enum Kind {
+    // A regular function call. Not every function call in the call stack is printed in diagnostics.
+    // This is only used if the original instruction doesn't have a location.
+    case call
+
+    // If the error is in a constructor, this is the place where the object/value is created.
+    case constructorCall
+
+    // If the error is in a specialized function, this is the place where the generic function is originally
+    // specialized with concrete types. This is useful if a specialized type is relevant for the error.
+    case specializedCall
+
+    // If the error is in a protocol witness method, this is the place where the existential is created.
+    case conformance
+  }
+
+  let location: Location
+  let kind: Kind
+
+  init(apply: ApplySite, callee: Function) {
+    self.location = apply.location
+    if let d = callee.location.decl, d is ConstructorDecl {
+      self.kind = .constructorCall
+    } else if callee.isSpecialization && !apply.parentFunction.isSpecialization {
+      self.kind = .specializedCall
+    } else {
+      self.kind = .call
+    }
+  }
+
+  init(location: Location, kind: Kind) {
+    self.location = location
+    self.kind = kind
+  }
+}
+
+private extension Function {
+  // The priority (1 = highest) which defines the order in which functions are checked.
+  // This is important to get good caller information in diagnostics.
+  var priority: Int {
+    // There might be functions without a location, e.g. `swift_readAtKeyPath` generated by SILGen for keypaths.
+    // It's okay to skip the ctor/dtor/method detection logic for those.
+    if location.hasValidLineNumber {
+      if let decl = location.decl {
+        if decl is DestructorDecl || decl is ConstructorDecl {
+          return 4
+        }
+        if let parent = decl.parent, parent is ClassDecl {
+          return 2
+        }
+      }
+    }
+    if isPossiblyUsedExternally {
+      return 1
+    }
+    return 3
+  }
+}
+
+private extension AllocBoxInst {
+  var allocsGenericValueTypeWithDeinit: Bool {
+    type.getBoxFields(in: parentFunction).contains { $0.hasGenericValueDeinit(in: parentFunction) }
+  }
+}
+
+private extension ApplySite {
+  var callsEmbeddedRuntimeFunction: Bool {
+    if let callee = referencedFunction,
+       !callee.isDefinition,
+       !callee.name.startsWith("$e")
+    {
+      return true
+    }
+    return false
+  }
+
+  var calleeHasGenericSelfMetatypeParameter: Bool {
+    let convention = FunctionConvention(for: callee.type.canonicalType, in: parentFunction)
+    guard convention.hasSelfParameter, let selfParam = convention.parameters.last else {
+      return false
+    }
+    let selfParamType = selfParam.type
+    return selfParamType.isMetatype && selfParamType.instanceTypeOfMetatype.isGenericTypeParameter
+  }
+}
+
+private extension Type {
+  func hasGenericValueDeinit(in function: Function) -> Bool {
+    guard isMoveOnly, let nominal = nominal else {
+      return false
+    }
+
+    if nominal.isGenericAtAnyLevel && nominal.valueTypeDestructor != nil {
+      return true
+    }
+
+    if isStruct {
+      if let fields = getNominalFields(in: function) {
+        return fields.contains { $0.hasGenericValueDeinit(in: function) }
+      }
+    } else if isEnum {
+      if let enumCases = getEnumCases(in: function) {
+        return enumCases.contains { $0.payload?.hasGenericValueDeinit(in: function) ?? false }
+      }
+    }
+    return false
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/ModulePasses/MandatoryPerformanceOptimizations.swift b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/MandatoryPerformanceOptimizations.swift
index ca4d1012b97fe..af12a0572d8e5 100644
--- a/SwiftCompilerSources/Sources/Optimizer/ModulePasses/MandatoryPerformanceOptimizations.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/MandatoryPerformanceOptimizations.swift
@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import AST
 import SIL
 
 /// Performs mandatory optimizations for performance-annotated functions, and global
@@ -40,9 +41,10 @@ let mandatoryPerformanceOptimizations = ModulePass(name: "mandatory-performance-
 
   optimizeFunctionsTopDown(using: &worklist, moduleContext)
 
-  if moduleContext.options.enableEmbeddedSwift {
-    // Print errors for generic functions in vtables, which is not allowed in embedded Swift.
-    checkVTablesForGenericFunctions(moduleContext)
+  // It's not required to set the perf_constraint flag on all functions in embedded mode.
+  // Embedded mode already implies that flag.
+  if !moduleContext.options.enableEmbeddedSwift {
+    setPerformanceConstraintFlags(moduleContext)
   }
 }
 
@@ -50,17 +52,9 @@ private func optimizeFunctionsTopDown(using worklist: inout FunctionWorklist,
                                       _ moduleContext: ModulePassContext) {
   while let f = worklist.pop() {
     moduleContext.transform(function: f) { context in
-      if !context.loadFunction(function: f, loadCalleesRecursively: true) {
-        return
-      }
-
-      // It's not required to set the perf_constraint flag on all functions in embedded mode.
-      // Embedded mode already implies that flag.
-      if !moduleContext.options.enableEmbeddedSwift {
-        f.set(isPerformanceConstraint: true, context)
+      if context.loadFunction(function: f, loadCalleesRecursively: true) {
+        optimize(function: f, context, moduleContext, &worklist)
       }
-
-      optimize(function: f, context, moduleContext, &worklist)
     }
 
     // Generic specialization takes care of removing metatype arguments of generic functions.
@@ -68,7 +62,18 @@ private func optimizeFunctionsTopDown(using worklist: inout FunctionWorklist,
     // We need handle this case with a function signature optimization.
     removeMetatypeArgumentsInCallees(of: f, moduleContext)
 
-    worklist.addCallees(of: f)
+    worklist.addCallees(of: f, moduleContext)
+  }
+}
+
+private func setPerformanceConstraintFlags(_ moduleContext: ModulePassContext) {
+  var worklist = FunctionWorklist()
+  for f in moduleContext.functions where f.performanceConstraints != .none && f.isDefinition {
+    worklist.pushIfNotVisited(f)
+  }
+  while let f = worklist.pop() {
+    moduleContext.transform(function: f) { f.set(isPerformanceConstraint: true, $0) }
+    worklist.addCallees(of: f, moduleContext)
   }
 }
 
@@ -112,7 +117,8 @@ private func optimize(function: Function, _ context: FunctionPassContext, _ modu
           }
         }
       case let metatype as MetatypeInst:
-        if context.options.enableEmbeddedSwift {
+        if context.options.enableEmbeddedSwift,
+           metatype.type.representationOfMetatype == .thick {
           let instanceType = metatype.type.loweredInstanceTypeOfMetatype(in: function)
           if instanceType.isClass {
             specializeVTable(forClassType: instanceType, errorLocation: metatype.location, moduleContext) {
@@ -131,17 +137,44 @@ private func optimize(function: Function, _ context: FunctionPassContext, _ modu
 
       case let initExRef as InitExistentialRefInst:
         if context.options.enableEmbeddedSwift {
-          specializeWitnessTables(for: initExRef, moduleContext, &worklist)
+          for c in initExRef.conformances where c.isConcrete {
+            specializeWitnessTable(for: c, moduleContext)
+            worklist.addWitnessMethods(of: c, moduleContext)
+          }
+        }
+
+      case let bi as BuiltinInst:
+        switch bi.id {
+        case .BuildOrdinaryTaskExecutorRef,
+             .BuildOrdinarySerialExecutorRef,
+             .BuildComplexEqualitySerialExecutorRef:
+          let conformance = bi.substitutionMap.conformances[0]
+          specializeWitnessTable(for: conformance, moduleContext)
+          worklist.addWitnessMethods(of: conformance, moduleContext)
+
+        default:
+          if !devirtualizeDeinits(of: bi, simplifyCtxt) {
+            // If invoked from SourceKit avoid reporting false positives when WMO is turned off for indexing purposes.
+            if moduleContext.enableWMORequiredDiagnostics {
+              context.diagnosticEngine.diagnose(.deinit_not_visible, at: bi.location)
+            }
+          }
         }
 
       // We need to de-virtualize deinits of non-copyable types to be able to specialize the deinitializers.
       case let destroyValue as DestroyValueInst:
         if !devirtualizeDeinits(of: destroyValue, simplifyCtxt) {
-          context.diagnosticEngine.diagnose(destroyValue.location.sourceLoc, .deinit_not_visible)
+          // If invoked from SourceKit avoid reporting false positives when WMO is turned off for indexing purposes.
+          if moduleContext.enableWMORequiredDiagnostics {
+            context.diagnosticEngine.diagnose(.deinit_not_visible, at: destroyValue.location)
+          }
         }
       case let destroyAddr as DestroyAddrInst:
         if !devirtualizeDeinits(of: destroyAddr, simplifyCtxt) {
-          context.diagnosticEngine.diagnose(destroyAddr.location.sourceLoc, .deinit_not_visible)
+          // If invoked from SourceKit avoid reporting false positives when WMO is turned off for indexing purposes.
+          if moduleContext.enableWMORequiredDiagnostics {
+            context.diagnosticEngine.diagnose(.deinit_not_visible, at: destroyAddr.location)
+          }
         }
 
       case let iem as InitExistentialMetatypeInst:
@@ -238,11 +271,13 @@ private func shouldInline(apply: FullApplySite, callee: Function, alreadyInlined
     return false
   }
 
-  if !callee.canBeInlinedIntoCaller(withSerializedKind: apply.parentFunction.serializedKind) &&
-     // Even if the serialization kind doesn't match, we need to make sure to inline witness method thunks
-     // in embedded swift.
-     callee.thunkKind != .thunk
-  {
+  guard callee.canBeInlinedIntoCaller(withSerializedKind: apply.parentFunction.serializedKind) ||
+        // Even if the serialization kind doesn't match, we need to make sure to inline witness method thunks
+        // in embedded swift.
+        callee.thunkKind == .thunk ||
+        // Force inlining transparent co-routines. This might be necessary if `-enable-testing` is turned on.
+        (apply is BeginApplyInst && callee.isTransparent)
+  else {
     return false
   }
 
@@ -267,7 +302,9 @@ private func shouldInline(apply: FullApplySite, callee: Function, alreadyInlined
     return false
   }
 
-  if apply.parentFunction.isGlobalInitOnceFunction && callee.inlineStrategy == .always {
+  if apply.parentFunction.isGlobalInitOnceFunction && (
+      callee.inlineStrategy == .heuristicAlways ||
+      callee.inlineStrategy == .always) {
     // Some arithmetic operations, like integer conversions, are not transparent but `inline(__always)`.
     // Force inlining them in global initializers so that it's possible to statically initialize the global.
     return true
@@ -282,51 +319,9 @@ private func shouldInline(apply: FullApplySite, callee: Function, alreadyInlined
   return false
 }
 
-private func specializeWitnessTables(for initExRef: InitExistentialRefInst, _ context: ModulePassContext,
-                                     _ worklist: inout FunctionWorklist)
-{
-  for c in initExRef.conformances where c.isConcrete {
-    let conformance = c.isInherited ? c.inheritedConformance : c
-    let origWitnessTable = context.lookupWitnessTable(for: conformance)
-    if conformance.isSpecialized {
-      if origWitnessTable == nil {
-        specializeWitnessTable(forConformance: conformance, errorLocation: initExRef.location, context) {
-          worklist.addWitnessMethods(of: $0)
-        }
-      }
-    } else if let origWitnessTable {
-      checkForGenericMethods(in: origWitnessTable, errorLocation: initExRef.location, context)
-    }
-  }
-}
-
-private func checkForGenericMethods(in witnessTable: WitnessTable,
-                                    errorLocation: Location,
-                                    _ context: ModulePassContext)
-{
-  for entry in witnessTable.entries {
-    if case .method(let requirement, let witness) = entry,
-       let witness,
-       witness.isGeneric
-    {
-      context.diagnosticEngine.diagnose(errorLocation.sourceLoc, .cannot_specialize_witness_method, requirement)
-      return
-    }
-  }
-}
-
-private func checkVTablesForGenericFunctions(_ context: ModulePassContext) {
-  for vTable in context.vTables where !vTable.class.isGenericAtAnyLevel {
-    for entry in vTable.entries where entry.implementation.isGeneric {
-      context.diagnosticEngine.diagnose(entry.methodDecl.location.sourceLoc, .non_final_generic_class_function)
-    }
-  }
-}
-
 private extension FullApplySite {
   func resultIsUsedInGlobalInitialization() -> SmallProjectionPath? {
-    guard parentFunction.isGlobalInitOnceFunction,
-          let global = parentFunction.getInitializedGlobal() else {
+    guard let global = parentFunction.initializedGlobal else {
       return nil
     }
 
@@ -411,7 +406,7 @@ private extension Value {
       //   var p = Point(x: 10, y: 20)
       //   let o = UnsafePointer(&p)
       // Therefore ignore the `end_access` use of a `begin_access`.
-      let relevantUses = singleUseValue.uses.ignoreDebugUses.ignoreUsers(ofType: EndAccessInst.self)
+      let relevantUses = singleUseValue.uses.ignoreDebugUses.ignoreUses(ofType: EndAccessInst.self)
 
       guard let use = relevantUses.singleUse else {
         return nil
@@ -450,39 +445,7 @@ private extension Value {
   }
 }
 
-private extension Function {
-  /// Analyzes the global initializer function and returns global it initializes (from `alloc_global` instruction).
-  func getInitializedGlobal() -> GlobalVariable? {
-    if !isDefinition {
-      return nil
-    }
-    for inst in self.entryBlock.instructions {
-      switch inst {
-      case let agi as AllocGlobalInst:
-        return agi.global
-      default:
-        break
-      }
-    }
-
-    return nil
-  }
-}
-
-fileprivate struct FunctionWorklist {
-  private(set) var functions = Array<Function>()
-  private var pushedFunctions = Set<Function>()
-  private var currentIndex = 0
-
-  mutating func pop() -> Function? {
-    if currentIndex < functions.count {
-      let f = functions[currentIndex]
-      currentIndex += 1
-      return f
-    }
-    return nil
-  }
-  
+extension FunctionWorklist {
   mutating func addAllMandatoryRequiredFunctions(of moduleContext: ModulePassContext) {
     for f in moduleContext.functions {
       // Performance annotated functions
@@ -490,20 +453,10 @@ fileprivate struct FunctionWorklist {
         pushIfNotVisited(f)
       }
       
-      // Annotated global init-once functions
-      if f.isGlobalInitOnceFunction {
-        if let global = f.getInitializedGlobal(),
-           global.mustBeInitializedStatically {
-          pushIfNotVisited(f)
-        }
-      }
-      
-      // @const global init-once functions
-      if f.isGlobalInitOnceFunction {
-        if let global = f.getInitializedGlobal(),
-           global.mustBeInitializedStatically {
-          pushIfNotVisited(f)
-        }
+      // Initializers of globals which must be initialized statically.
+      if let global = f.initializedGlobal,
+         global.mustBeInitializedStatically {
+        pushIfNotVisited(f)
       }
     }
   }
@@ -515,9 +468,15 @@ fileprivate struct FunctionWorklist {
     return
   }
 
-  mutating func addCallees(of function: Function) {
+  mutating func addCallees(of function: Function, _ context: ModulePassContext) {
     for inst in function.instructions {
       switch inst {
+      case let fri as FunctionRefInst:
+        // In embedded swift all reachable functions must be handled - even if they are not called,
+        // e.g. referenced by a global.
+        if context.options.enableEmbeddedSwift {
+          pushIfNotVisited(fri.referencedFunction)
+        }
       case let apply as ApplySite:
         if let callee = apply.referencedFunction {
           pushIfNotVisited(callee)
@@ -528,32 +487,78 @@ fileprivate struct FunctionWorklist {
           if let fri = bi.operands[1].value as? FunctionRefInst {
             pushIfNotVisited(fri.referencedFunction)
           }
-          break;
         default:
           break
         }
+      case let alloc as AllocRefInst:
+        if context.options.enableEmbeddedSwift {
+          addVTableMethods(forClassType: alloc.type, context)
+        }
+      case let metatype as MetatypeInst:
+        if context.options.enableEmbeddedSwift {
+          let instanceType = metatype.type.loweredInstanceTypeOfMetatype(in: function)
+          if instanceType.isClass {
+            addVTableMethods(forClassType: instanceType, context)
+          }
+        }
+
       default:
         break
       }
     }
   }
 
-  mutating func addWitnessMethods(of witnessTable: WitnessTable) {
-    for entry in witnessTable.entries {
-      if case .method(_, let witness) = entry,
-         let method = witness,
-         // A new witness table can still contain a generic function if the method couldn't be specialized for
-         // some reason and an error has been printed. Exclude generic functions to not run into an assert later.
-         !method.isGeneric
-      {
-        pushIfNotVisited(method)
-      }
+  mutating func addVTableMethods(forClassType classType: Type, _ context: ModulePassContext) {
+    guard let vtable = classType.isGenericAtAnyLevel ?
+                        context.lookupSpecializedVTable(for: classType) :
+                        context.lookupVTable(for: classType.nominal!)
+    else {
+      return
     }
+    for entry in vtable.entries where !entry.implementation.isGeneric {
+      pushIfNotVisited(entry.implementation)
+    }
+  }
+
+  mutating func addWitnessMethods(of conformance: Conformance, _ context: ModulePassContext) {
+    var visited = Set<Conformance>()
+    addWitnessMethodsRecursively(of: conformance, visited: &visited, context)
   }
 
-  mutating func pushIfNotVisited(_ element: Function) {
-    if pushedFunctions.insert(element).inserted {
-      functions.append(element)
+  private mutating func addWitnessMethodsRecursively(of conformance: Conformance,
+                                                     visited: inout Set<Conformance>,
+                                                     _ context: ModulePassContext)
+  {
+    guard conformance.isConcrete,
+          visited.insert(conformance).inserted
+    else {
+      return
+    }
+    let witnessTable: WitnessTable
+    if let wt = context.lookupWitnessTable(for: conformance) {
+      witnessTable = wt
+    } else if let wt = context.lookupWitnessTable(for: conformance.rootConformance) {
+      witnessTable = wt
+    } else {
+      return
+    }
+    for entry in witnessTable.entries {
+      switch entry {
+      case .invalid, .associatedType:
+        break
+      case .method(_, let witness):
+        if let method = witness,
+           // A new witness table can still contain a generic function if the method couldn't be specialized for
+           // some reason and an error has been printed. Exclude generic functions to not run into an assert later.
+           !method.isGeneric
+        {
+          pushIfNotVisited(method)
+        }
+      case .baseProtocol(_, let baseConf):
+        addWitnessMethodsRecursively(of: baseConf, visited: &visited, context)
+      case .associatedConformance(_, let assocConf):
+        addWitnessMethodsRecursively(of: assocConf, visited: &visited, context)
+      }
     }
   }
 }
diff --git a/SwiftCompilerSources/Sources/Optimizer/ModulePasses/StackProtection.swift b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/StackProtection.swift
index 96b31bc5dc48a..586ebe6751486 100644
--- a/SwiftCompilerSources/Sources/Optimizer/ModulePasses/StackProtection.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/ModulePasses/StackProtection.swift
@@ -113,7 +113,7 @@ private struct StackProtectionOptimization {
       process(instruction: inst, in: function, mustFixStackNesting: &mustFixStackNesting, context)
     }
     if mustFixStackNesting {
-      function.fixStackNesting(context)
+      context.fixStackNesting(in: function)
     }
   }
 
@@ -332,20 +332,16 @@ private struct StackProtectionOptimization {
 
     let function = argument.parentFunction
     let entryBlock = function.entryBlock
-    let loc = entryBlock.instructions.first!.location.autoGenerated
+    let loc = entryBlock.instructions.first!.location.asAutoGenerated
     let builder = Builder(atBeginOf: entryBlock, location: loc, context)
     let temporary = builder.createAllocStack(argument.type)
     argument.uses.replaceAll(with: temporary, context)
 
     builder.createCopyAddr(from: argument, to: temporary, takeSource: true, initializeDest: true)
 
-    for block in function.blocks {
-      let terminator = block.terminator
-      if terminator.isFunctionExiting {
-        let exitBuilder = Builder(before: terminator, location: terminator.location.autoGenerated, context)
-        exitBuilder.createCopyAddr(from: temporary, to: argument, takeSource: true, initializeDest: true)
-        exitBuilder.createDeallocStack(temporary)
-      }
+    Builder.insertCleanupAtFunctionExits(of: function, context) { builder in
+      builder.createCopyAddr(from: temporary, to: argument, takeSource: true, initializeDest: true)
+      builder.createDeallocStack(temporary)
     }
     log("move addr protection in \(function.name): \(argument)")
     
@@ -362,13 +358,13 @@ private struct StackProtectionOptimization {
       return
     }
   
-    let builder = Builder(after: beginAccess, location: beginAccess.location.autoGenerated, context)
+    let builder = Builder(after: beginAccess, location: beginAccess.location.asAutoGenerated, context)
     let temporary = builder.createAllocStack(beginAccess.type)
 
-    beginAccess.uses.ignoreUsers(ofType: EndAccessInst.self).replaceAll(with: temporary, context)
+    beginAccess.uses.ignoreUses(ofType: EndAccessInst.self).replaceAll(with: temporary, context)
 
     for endAccess in beginAccess.endInstructions {
-      let endBuilder = Builder(before: endAccess, location: endAccess.location.autoGenerated, context)
+      let endBuilder = Builder(before: endAccess, location: endAccess.location.asAutoGenerated, context)
       endBuilder.createCopyAddr(from: temporary, to: beginAccess, takeSource: true, initializeDest: true)
       endBuilder.createDeallocStack(temporary)
     }
diff --git a/SwiftCompilerSources/Sources/Optimizer/PassManager/CMakeLists.txt b/SwiftCompilerSources/Sources/Optimizer/PassManager/CMakeLists.txt
index a1da2f6e96fa4..4a46ced58a617 100644
--- a/SwiftCompilerSources/Sources/Optimizer/PassManager/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/Optimizer/PassManager/CMakeLists.txt
@@ -7,9 +7,10 @@
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 swift_compiler_sources(Optimizer
-  Context.swift
+  ContextCommon.swift
+  FunctionPassContext.swift
   ModulePassContext.swift
   Options.swift
   Passes.swift
-  PassRegistration.swift)
-
+  PassRegistration.swift
+  SimplifyContext.swift)
diff --git a/SwiftCompilerSources/Sources/Optimizer/PassManager/Context.swift b/SwiftCompilerSources/Sources/Optimizer/PassManager/Context.swift
deleted file mode 100644
index 6803362b43395..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/PassManager/Context.swift
+++ /dev/null
@@ -1,803 +0,0 @@
-//===--- Context.swift - defines the context types ------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import AST
-import SIL
-import OptimizerBridging
-
-/// The base type of all contexts.
-protocol Context {
-  var _bridged: BridgedPassContext { get }
-}
-
-extension Context {
-  var options: Options { Options(_bridged: _bridged) }
-
-  var diagnosticEngine: DiagnosticEngine {
-    return DiagnosticEngine(bridged: _bridged.getDiagnosticEngine())
-  }
-
-  // The calleeAnalysis is not specific to a function and therefore can be provided in
-  // all contexts.
-  var calleeAnalysis: CalleeAnalysis {
-    let bridgeCA = _bridged.getCalleeAnalysis()
-    return CalleeAnalysis(bridged: bridgeCA)
-  }
-
-  var hadError: Bool { _bridged.hadError() }
-
-  var silStage: SILStage {
-    switch _bridged.getSILStage() {
-      case .Raw:       return .raw
-      case .Canonical: return .canonical
-      case .Lowered:   return .lowered
-      default:         fatalError("unhandled SILStage case")
-    }
-  }
-
-  var currentModuleContext: ModuleDecl {
-    _bridged.getCurrentModuleContext().getAs(ModuleDecl.self)
-  }
-
-  var moduleIsSerialized: Bool { _bridged.moduleIsSerialized() }
-
-  /// Enable diagnostics requiring WMO (for @noLocks, @noAllocation
-  /// annotations, Embedded Swift, and class specialization). SourceKit is the
-  /// only consumer that has this disabled today (as it disables WMO
-  /// explicitly).
-  var enableWMORequiredDiagnostics: Bool {
-    _bridged.enableWMORequiredDiagnostics()
-  }
-
-  func canMakeStaticObjectReadOnly(objectType: Type) -> Bool {
-    _bridged.canMakeStaticObjectReadOnly(objectType.bridged)
-  }
-
-  func lookupDeinit(ofNominal: NominalTypeDecl) -> Function? {
-    _bridged.lookUpNominalDeinitFunction(ofNominal.bridged).function
-  }
-
-  func getBuiltinIntegerType(bitWidth: Int) -> Type { _bridged.getBuiltinIntegerType(bitWidth).type }
-
-  func lookupFunction(name: String) -> Function? {
-    name._withBridgedStringRef {
-      _bridged.lookupFunction($0).function
-    }
-  }
-
-  func lookupWitnessTable(for conformance: Conformance) -> WitnessTable? {
-    return _bridged.lookupWitnessTable(conformance.bridged).witnessTable
-  }
-
-  func lookupVTable(for classDecl: NominalTypeDecl) -> VTable? {
-    return _bridged.lookupVTable(classDecl.bridged).vTable
-  }
-
-  func lookupSpecializedVTable(for classType: Type) -> VTable? {
-    return _bridged.lookupSpecializedVTable(classType.bridged).vTable
-  }
-
-  func getSpecializedConformance(of genericConformance: Conformance,
-                                 for type: AST.`Type`,
-                                 substitutions: SubstitutionMap) -> Conformance
-  {
-    let c = _bridged.getSpecializedConformance(genericConformance.bridged, type.bridged, substitutions.bridged)
-    return Conformance(bridged: c)
-  }
-
-  func notifyNewFunction(function: Function, derivedFrom: Function) {
-    _bridged.addFunctionToPassManagerWorklist(function.bridged, derivedFrom.bridged)
-  }
-}
-
-/// A context which allows mutation of a function's SIL.
-protocol MutatingContext : Context {
-  // Called by all instruction mutations, including inserted new instructions.
-  var notifyInstructionChanged: (Instruction) -> () { get }
-}
-
-extension MutatingContext {
-  func notifyInvalidatedStackNesting() { _bridged.notifyInvalidatedStackNesting() }
-  var needFixStackNesting: Bool { _bridged.getNeedFixStackNesting() }
-
-  func verifyIsTransforming(function: Function) {
-    precondition(_bridged.isTransforming(function.bridged), "pass modifies wrong function")
-  }
-
-  /// Splits the basic block, which contains `inst`, before `inst` and returns the
-  /// new block.
-  ///
-  /// `inst` and all subsequent instructions are moved to the new block, while all
-  /// instructions _before_ `inst` remain in the original block.
-  func splitBlock(before inst: Instruction) -> BasicBlock {
-    notifyBranchesChanged()
-    return _bridged.splitBlockBefore(inst.bridged).block
-  }
-
-  /// Splits the basic block, which contains `inst`, after `inst` and returns the
-  /// new block.
-  ///
-  /// All subsequent instructions after `inst` are moved to the new block, while `inst` and all
-  /// instructions _before_ `inst` remain in the original block.
-  func splitBlock(after inst: Instruction) -> BasicBlock {
-    notifyBranchesChanged()
-    return _bridged.splitBlockAfter(inst.bridged).block
-  }
-
-  func createBlock(after block: BasicBlock) -> BasicBlock {
-    notifyBranchesChanged()
-    return _bridged.createBlockAfter(block.bridged).block
-  }
-
-  func erase(instruction: Instruction) {
-    if !instruction.isInStaticInitializer {
-      verifyIsTransforming(function: instruction.parentFunction)
-    }
-    if instruction is FullApplySite {
-      notifyCallsChanged()
-    }
-    if instruction is TermInst {
-      notifyBranchesChanged()
-    }
-    notifyInstructionsChanged()
-
-    _bridged.eraseInstruction(instruction.bridged)
-  }
-
-  func erase(instructionIncludingAllUsers inst: Instruction) {
-    if inst.isDeleted {
-      return
-    }
-    for result in inst.results {
-      for use in result.uses {
-        erase(instructionIncludingAllUsers: use.instruction)
-      }
-    }
-    erase(instruction: inst)
-  }
-
-  func erase<S: Sequence>(instructions: S) where S.Element: Instruction {
-    for inst in instructions {
-      erase(instruction: inst)
-    }
-  }
-
-  func erase(instructionIncludingDebugUses inst: Instruction) {
-    precondition(inst.results.allSatisfy { $0.uses.ignoreDebugUses.isEmpty })
-    erase(instructionIncludingAllUsers: inst)
-  }
-
-  func erase(block: BasicBlock) {
-    _bridged.eraseBlock(block.bridged)
-  }
-
-  func tryOptimizeApplyOfPartialApply(closure: PartialApplyInst) -> Bool {
-    if _bridged.tryOptimizeApplyOfPartialApply(closure.bridged) {
-      notifyInstructionsChanged()
-      notifyCallsChanged()
-
-      for use in closure.callee.uses {
-        if use.instruction is FullApplySite {
-          notifyInstructionChanged(use.instruction)
-        }
-      }
-      return true
-    }
-    return false
-  }
-
-  func tryDeleteDeadClosure(closure: SingleValueInstruction, needKeepArgsAlive: Bool = true) -> Bool {
-    if _bridged.tryDeleteDeadClosure(closure.bridged, needKeepArgsAlive) {
-      notifyInstructionsChanged()
-      return true
-    }
-    return false
-  }
-
-  func tryDevirtualize(apply: FullApplySite, isMandatory: Bool) -> ApplySite? {
-    let result = _bridged.tryDevirtualizeApply(apply.bridged, isMandatory)
-    if let newApply = result.newApply.instruction {
-      erase(instruction: apply)
-      notifyInstructionsChanged()
-      notifyCallsChanged()
-      if result.cfgChanged {
-        notifyBranchesChanged()
-      }
-      notifyInstructionChanged(newApply)
-      return newApply as! FullApplySite
-    }
-    return nil
-  }
-  
-  func tryOptimizeKeypath(apply: FullApplySite) -> Bool {
-    return _bridged.tryOptimizeKeypath(apply.bridged)
-  }
-
-  func inlineFunction(apply: FullApplySite, mandatoryInline: Bool) {
-    // This is only a best-effort attempt to notify the new cloned instructions as changed.
-    // TODO: get a list of cloned instructions from the `inlineFunction`
-    let instAfterInling: Instruction?
-    switch apply {
-    case is ApplyInst:
-      instAfterInling = apply.next
-    case let beginApply as BeginApplyInst:
-      let next = beginApply.next!
-      instAfterInling = (next is EndApplyInst ? nil : next)
-    case is TryApplyInst:
-      instAfterInling = apply.parentBlock.next?.instructions.first
-    default:
-      instAfterInling = nil
-    }
-
-    _bridged.inlineFunction(apply.bridged, mandatoryInline)
-
-    if let instAfterInling = instAfterInling {
-      notifyNewInstructions(from: apply, to: instAfterInling)
-    }
-  }
-
-  func loadFunction(function: Function, loadCalleesRecursively: Bool) -> Bool {
-    if function.isDefinition {
-      return true
-    }
-    _bridged.loadFunction(function.bridged, loadCalleesRecursively)
-    return function.isDefinition
-  }
-
-  private func notifyNewInstructions(from: Instruction, to: Instruction) {
-    var inst = from
-    while inst != to {
-      if !inst.isDeleted {
-        notifyInstructionChanged(inst)
-      }
-      if let next = inst.next {
-        inst = next
-      } else {
-        inst = inst.parentBlock.next!.instructions.first!
-      }
-    }
-  }
-
-  func getContextSubstitutionMap(for type: Type) -> SubstitutionMap {
-    SubstitutionMap(bridged: _bridged.getContextSubstitutionMap(type.bridged))
-  }
-
-  func notifyInstructionsChanged() {
-    _bridged.asNotificationHandler().notifyChanges(.instructionsChanged)
-  }
-
-  func notifyCallsChanged() {
-    _bridged.asNotificationHandler().notifyChanges(.callsChanged)
-  }
-
-  func notifyBranchesChanged() {
-    _bridged.asNotificationHandler().notifyChanges(.branchesChanged)
-  }
-
-  /// Notifies the pass manager that the optimization result of the current pass depends
-  /// on the body (i.e. SIL instructions) of another function than the currently optimized one.
-  func notifyDependency(onBodyOf otherFunction: Function) {
-    _bridged.notifyDependencyOnBodyOf(otherFunction.bridged)
-  }
-}
-
-/// The context which is passed to the run-function of a FunctionPass.
-struct FunctionPassContext : MutatingContext {
-  let _bridged: BridgedPassContext
-
-  // A no-op.
-  var notifyInstructionChanged: (Instruction) -> () { return { inst in } }
-
-  func continueWithNextSubpassRun(for inst: Instruction? = nil) -> Bool {
-    return _bridged.continueWithNextSubpassRun(inst.bridged)
-  }
-
-  func createSimplifyContext(preserveDebugInfo: Bool, notifyInstructionChanged: @escaping (Instruction) -> ()) -> SimplifyContext {
-    SimplifyContext(_bridged: _bridged, notifyInstructionChanged: notifyInstructionChanged, preserveDebugInfo: preserveDebugInfo)
-  }
-
-  var deadEndBlocks: DeadEndBlocksAnalysis {
-    let bridgeDEA = _bridged.getDeadEndBlocksAnalysis()
-    return DeadEndBlocksAnalysis(bridged: bridgeDEA)
-  }
-
-  var dominatorTree: DominatorTree {
-    let bridgedDT = _bridged.getDomTree()
-    return DominatorTree(bridged: bridgedDT)
-  }
-
-  var postDominatorTree: PostDominatorTree {
-    let bridgedPDT = _bridged.getPostDomTree()
-    return PostDominatorTree(bridged: bridgedPDT)
-  }
-
-  var swiftArrayDecl: NominalTypeDecl {
-    _bridged.getSwiftArrayDecl().getAs(NominalTypeDecl.self)
-  }
-
-  func loadFunction(name: StaticString, loadCalleesRecursively: Bool) -> Function? {
-    return name.withUTF8Buffer { (nameBuffer: UnsafeBufferPointer<UInt8>) in
-      let nameStr = BridgedStringRef(data: nameBuffer.baseAddress, count: nameBuffer.count)
-      return _bridged.loadFunction(nameStr, loadCalleesRecursively).function
-    }
-  }
-
-  /// Looks up a function in the `Swift` module.
-  /// The `name` is the source name of the function and not the mangled name.
-  /// Returns nil if no such function or multiple matching functions are found.
-  func lookupStdlibFunction(name: StaticString) -> Function? {
-    return name.withUTF8Buffer { (nameBuffer: UnsafeBufferPointer<UInt8>) in
-      let nameStr = BridgedStringRef(data: nameBuffer.baseAddress, count: nameBuffer.count)
-      return _bridged.lookupStdlibFunction(nameStr).function
-    }
-  }
-
-  func modifyEffects(in function: Function, _ body: (inout FunctionEffects) -> ()) {
-    notifyEffectsChanged()
-    function._modifyEffects(body)
-  }
-
-  fileprivate func notifyEffectsChanged() {
-    _bridged.asNotificationHandler().notifyChanges(.effectsChanged)
-  }
-
-  func eliminateDeadAllocations(in function: Function) -> Bool {
-    if _bridged.eliminateDeadAllocations(function.bridged) {
-      notifyInstructionsChanged()
-      return true
-    }
-    return false
-  }
-
-  func specializeClassMethodInst(_ cm: ClassMethodInst) -> Bool {
-    if _bridged.specializeClassMethodInst(cm.bridged) {
-      notifyInstructionsChanged()
-      notifyCallsChanged()
-      return true
-    }
-    return false
-  }
-
-  func specializeWitnessMethodInst(_ wm: WitnessMethodInst) -> Bool {
-    if _bridged.specializeWitnessMethodInst(wm.bridged) {
-      notifyInstructionsChanged()
-      notifyCallsChanged()
-      return true
-    }
-    return false
-  }
-
-  func specializeApplies(in function: Function, isMandatory: Bool) -> Bool {
-    if _bridged.specializeAppliesInFunction(function.bridged, isMandatory) {
-      notifyInstructionsChanged()
-      notifyCallsChanged()
-      return true
-    }
-    return false
-  }
-
-  func mangleOutlinedVariable(from function: Function) -> String {
-    return String(taking: _bridged.mangleOutlinedVariable(function.bridged))
-  }
-
-  func mangle(withClosureArguments closureArgs: [Value], closureArgIndices: [Int], from applySiteCallee: Function) -> String {
-    closureArgs.withBridgedValues { bridgedClosureArgsRef in
-      closureArgIndices.withBridgedArrayRef{bridgedClosureArgIndicesRef in 
-        String(taking: _bridged.mangleWithClosureArgs(
-          bridgedClosureArgsRef, 
-          bridgedClosureArgIndicesRef, 
-          applySiteCallee.bridged
-        ))
-      }
-    }
-  }
-
-  func createGlobalVariable(name: String, type: Type, linkage: Linkage, isLet: Bool) -> GlobalVariable {
-    let gv = name._withBridgedStringRef {
-      _bridged.createGlobalVariable($0, type.bridged, linkage.bridged, isLet)
-    }
-    return gv.globalVar
-  }
-
-  func createFunctionForClosureSpecialization(from applySiteCallee: Function, withName specializedFunctionName: String, 
-                                              withParams specializedParameters: [ParameterInfo], 
-                                              withSerialization isSerialized: Bool) -> Function 
-  {
-    return specializedFunctionName._withBridgedStringRef { nameRef in
-      let bridgedParamInfos = specializedParameters.map { $0._bridged }
-
-      return bridgedParamInfos.withUnsafeBufferPointer { paramBuf in
-        _bridged.ClosureSpecializer_createEmptyFunctionWithSpecializedSignature(nameRef, paramBuf.baseAddress, 
-                                                                                paramBuf.count, 
-                                                                                applySiteCallee.bridged, 
-                                                                                isSerialized).function
-      }
-    }
-  }
-
-  func buildSpecializedFunction<T>(specializedFunction: Function, buildFn: (Function, FunctionPassContext) -> T) -> T {
-    let nestedFunctionPassContext = 
-        FunctionPassContext(_bridged: _bridged.initializeNestedPassContext(specializedFunction.bridged))
-
-      defer { _bridged.deinitializedNestedPassContext() }
-
-      return buildFn(specializedFunction, nestedFunctionPassContext)
-  }
-
-  /// Makes sure that the lifetime of `value` ends at all control flow paths, even in dead-end blocks.
-  /// Inserts destroys in dead-end blocks if those are missing.
-  func completeLifetime(of value: Value) {
-    if _bridged.completeLifetime(value.bridged) {
-      notifyInstructionsChanged()
-    }
-  }
-}
-
-struct SimplifyContext : MutatingContext {
-  let _bridged: BridgedPassContext
-  let notifyInstructionChanged: (Instruction) -> ()
-  let preserveDebugInfo: Bool
-}
-
-extension Type {
-  func getStaticSize(context: SimplifyContext) -> Int? {
-    let v = context._bridged.getStaticSize(self.bridged)
-    return v == -1 ? nil : v
-  }
-  
-  func getStaticAlignment(context: SimplifyContext) -> Int? {
-    let v = context._bridged.getStaticAlignment(self.bridged)
-    return v == -1 ? nil : v
-  }
-  
-  func getStaticStride(context: SimplifyContext) -> Int? {
-    let v = context._bridged.getStaticStride(self.bridged)
-    return v == -1 ? nil : v
-  }
-}
-
-//===----------------------------------------------------------------------===//
-//                          Builder initialization
-//===----------------------------------------------------------------------===//
-
-private extension Instruction {
-  /// Returns self, unless self is a meta instruction, in which case the next
-  /// non-meta instruction is returned. Returns nil if there are no non-meta
-  /// instructions in the basic block.
-  var nextNonMetaInstruction: Instruction? {
-    for inst in InstructionList(first: self) where !(inst is MetaInstruction) {
-      return inst
-    }
-    return nil
-  }
-
-  /// Returns the next interesting location. As it is impossible to set a
-  /// breakpoint on a meta instruction, those are skipped.
-  /// However, we don't want to take a location with different inlining
-  /// information than this instruction, so in that case, we will return the
-  /// location of the meta instruction. If the meta instruction is the only
-  /// instruction in the basic block, we also take its location.
-  var locationOfNextNonMetaInstruction: Location {
-    let location = self.location
-    guard !location.isInlined,
-          let nextLocation = nextNonMetaInstruction?.location,
-          !nextLocation.isInlined else {
-      return location
-    }
-    return nextLocation
-  }
-}
-
-extension Builder {
-  /// Creates a builder which inserts _before_ `insPnt`, using a custom `location`.
-  init(before insPnt: Instruction, location: Location, _ context: some MutatingContext) {
-    context.verifyIsTransforming(function: insPnt.parentFunction)
-    self.init(insertAt: .before(insPnt), location: location,
-              context.notifyInstructionChanged, context._bridged.asNotificationHandler())
-  }
-
-  /// Creates a builder which inserts before `insPnt`, using `insPnt`'s next
-  /// non-meta instruction's location.
-  /// This function should be used when moving code to an unknown insert point,
-  /// when we want to inherit the location of the closest non-meta instruction.
-  /// For replacing an existing meta instruction with another, use
-  /// ``Builder.init(replacing:_:)``.
-  init(before insPnt: Instruction, _ context: some MutatingContext) {
-    context.verifyIsTransforming(function: insPnt.parentFunction)
-    self.init(insertAt: .before(insPnt),
-              location: insPnt.locationOfNextNonMetaInstruction,
-              context.notifyInstructionChanged, context._bridged.asNotificationHandler())
-  }
-
-  /// Creates a builder which inserts _before_ `insPnt`, using the exact location of `insPnt`,
-  /// for the purpose of replacing that meta instruction with an equivalent instruction.
-  /// This function does not delete `insPnt`.
-  init(replacing insPnt: MetaInstruction, _ context: some MutatingContext) {
-    context.verifyIsTransforming(function: insPnt.parentFunction)
-    self.init(insertAt: .before(insPnt), location: insPnt.location,
-              context.notifyInstructionChanged, context._bridged.asNotificationHandler())
-  }
-
-  /// Creates a builder which inserts _after_ `insPnt`, using a custom `location`.
-  ///
-  /// TODO: this is usually incorrect for terminator instructions. Instead use
-  /// `Builder.insert(after:location:_:insertFunc)` from OptUtils.swift. Rename this to afterNonTerminator.
-  init(after insPnt: Instruction, location: Location, _ context: some MutatingContext) {
-    context.verifyIsTransforming(function: insPnt.parentFunction)
-    guard let nextInst = insPnt.next else {
-      fatalError("cannot insert an instruction after a block terminator.")
-    }
-    self.init(insertAt: .before(nextInst), location: location,
-              context.notifyInstructionChanged, context._bridged.asNotificationHandler())
-  }
-
-  /// Creates a builder which inserts _after_ `insPnt`, using `insPnt`'s next
-  /// non-meta instruction's location.
-  ///
-  /// TODO: this is incorrect for terminator instructions. Instead use `Builder.insert(after:location:_:insertFunc)`
-  /// from OptUtils.swift. Rename this to afterNonTerminator.
-  init(after insPnt: Instruction, _ context: some MutatingContext) {
-    self.init(after: insPnt, location: insPnt.locationOfNextNonMetaInstruction, context)
-  }
-
-  /// Creates a builder which inserts at the end of `block`, using a custom `location`.
-  init(atEndOf block: BasicBlock, location: Location, _ context: some MutatingContext) {
-    context.verifyIsTransforming(function: block.parentFunction)
-    self.init(insertAt: .atEndOf(block), location: location,
-              context.notifyInstructionChanged, context._bridged.asNotificationHandler())
-  }
-
-  /// Creates a builder which inserts at the begin of `block`, using a custom `location`.
-  init(atBeginOf block: BasicBlock, location: Location, _ context: some MutatingContext) {
-    context.verifyIsTransforming(function: block.parentFunction)
-    let firstInst = block.instructions.first!
-    self.init(insertAt: .before(firstInst), location: location,
-              context.notifyInstructionChanged, context._bridged.asNotificationHandler())
-  }
-
-  /// Creates a builder which inserts at the begin of `block`, using the location of the first
-  /// non-meta instruction of `block`.
-  init(atBeginOf block: BasicBlock, _ context: some MutatingContext) {
-    context.verifyIsTransforming(function: block.parentFunction)
-    let firstInst = block.instructions.first!
-    self.init(insertAt: .before(firstInst),
-              location: firstInst.locationOfNextNonMetaInstruction,
-              context.notifyInstructionChanged, context._bridged.asNotificationHandler())
-  }
-
-  /// Creates a builder which inserts instructions into an empty function, using the location of the function itself.
-  init(atStartOf function: Function, _ context: some MutatingContext) {
-    context.verifyIsTransforming(function: function)
-    self.init(insertAt: .atStartOf(function), location: function.location,
-              context.notifyInstructionChanged, context._bridged.asNotificationHandler())
-  }
-
-  init(staticInitializerOf global: GlobalVariable, _ context: some MutatingContext) {
-    self.init(insertAt: .staticInitializer(global),
-              location: Location.artificialUnreachableLocation,
-              { _ in }, context._bridged.asNotificationHandler())
-  }
-}
-
-//===----------------------------------------------------------------------===//
-//                          Modifying the SIL
-//===----------------------------------------------------------------------===//
-
-extension Undef {
-  static func get(type: Type, _ context: some MutatingContext) -> Undef {
-    context._bridged.getSILUndef(type.bridged).value as! Undef
-  }
-}
-
-extension BasicBlock {
-  func addArgument(type: Type, ownership: Ownership, _ context: some MutatingContext) -> Argument {
-    context.notifyInstructionsChanged()
-    return bridged.addBlockArgument(type.bridged, ownership._bridged).argument
-  }
-  
-  func addFunctionArgument(type: Type, _ context: some MutatingContext) -> FunctionArgument {
-    context.notifyInstructionsChanged()
-    return bridged.addFunctionArgument(type.bridged).argument as! FunctionArgument
-  }
-
-  func eraseArgument(at index: Int, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.eraseArgument(index)
-  }
-
-  func moveAllInstructions(toBeginOf otherBlock: BasicBlock, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    context.notifyBranchesChanged()
-    bridged.moveAllInstructionsToBegin(otherBlock.bridged)
-  }
-
-  func moveAllInstructions(toEndOf otherBlock: BasicBlock, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    context.notifyBranchesChanged()
-    bridged.moveAllInstructionsToEnd(otherBlock.bridged)
-  }
-
-  func eraseAllArguments(_ context: some MutatingContext) {
-    // Arguments are stored in an array. We need to erase in reverse order to avoid quadratic complexity.
-    for argIdx in (0 ..< arguments.count).reversed() {
-      eraseArgument(at: argIdx, context)
-    }
-  }
-
-  func moveAllArguments(to otherBlock: BasicBlock, _ context: some MutatingContext) {
-    bridged.moveArgumentsTo(otherBlock.bridged)
-  }
-}
-
-extension Argument {
-  func set(reborrow: Bool, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.setReborrow(reborrow)
-  }
-}
-
-extension AllocRefInstBase {
-  func setIsStackAllocatable(_ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.AllocRefInstBase_setIsStackAllocatable()
-    context.notifyInstructionChanged(self)
-  }
-}
-
-extension Sequence where Element == Operand {
-  func replaceAll(with replacement: Value, _ context: some MutatingContext) {
-    for use in self {
-      use.set(to: replacement, context)
-    }
-  }
-}
-
-extension Operand {
-  func set(to value: Value, _ context: some MutatingContext) {
-    instruction.setOperand(at: index, to: value, context)
-  }
-
-  func changeOwnership(from: Ownership, to: Ownership, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.changeOwnership(from._bridged, to._bridged)
-    context.notifyInstructionChanged(instruction)
-  }
-}
-
-extension Instruction {
-  func setOperand(at index : Int, to value: Value, _ context: some MutatingContext) {
-    if let apply = self as? FullApplySite, apply.isCallee(operand: operands[index]) {
-      context.notifyCallsChanged()
-    }
-    context.notifyInstructionsChanged()
-    bridged.setOperand(index, value.bridged)
-    context.notifyInstructionChanged(self)
-  }
-
-  func move(before otherInstruction: Instruction, _ context: some MutatingContext) {
-    BridgedPassContext.moveInstructionBefore(bridged, otherInstruction.bridged)
-    context.notifyInstructionsChanged()
-  }
-}
-
-extension BuiltinInst {
-  func constantFold(_ context: some MutatingContext) -> Value? {
-    context._bridged.constantFoldBuiltin(bridged).value
-  }
-}
-
-extension RefCountingInst {
-  func setAtomicity(isAtomic: Bool, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.RefCountingInst_setIsAtomic(isAtomic)
-    context.notifyInstructionChanged(self)
-  }
-}
-
-extension AllocRefInst {
-  func setIsBare(_ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.AllocRefInst_setIsBare()
-    context.notifyInstructionChanged(self)
-  }
-}
-
-extension RefElementAddrInst {
-  func set(isImmutable: Bool, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.RefElementAddrInst_setImmutable(isImmutable)
-    context.notifyInstructionChanged(self)
-  }
-}
-
-extension GlobalAddrInst {
-  func clearToken(_ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.GlobalAddrInst_clearToken()
-    context.notifyInstructionChanged(self)
-  }
-}
-
-extension GlobalValueInst {
-  func setIsBare(_ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.GlobalValueInst_setIsBare()
-    context.notifyInstructionChanged(self)
-  }
-}
-
-extension LoadInst {
-  func set(ownership: LoadInst.LoadOwnership, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.LoadInst_setOwnership(ownership.rawValue)
-    context.notifyInstructionChanged(self)
-  }
-}
-
-extension PointerToAddressInst {
-  func set(alignment: Int?, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.PointerToAddressInst_setAlignment(UInt64(alignment ?? 0))
-    context.notifyInstructionChanged(self)
-  }
-}
-
-extension TermInst {
-  func replaceBranchTarget(from fromBlock: BasicBlock, to toBlock: BasicBlock, _ context: some MutatingContext) {
-    context.notifyBranchesChanged()
-    bridged.TermInst_replaceBranchTarget(fromBlock.bridged, toBlock.bridged)
-  }
-}
-
-extension ForwardingInstruction {
-  func setForwardingOwnership(to ownership: Ownership, _ context: some MutatingContext) {
-    context.notifyInstructionsChanged()
-    bridged.ForwardingInst_setForwardingOwnership(ownership._bridged)
-  }
-}
-
-extension Function {
-  func set(needStackProtection: Bool, _ context: FunctionPassContext) {
-    context.notifyEffectsChanged()
-    bridged.setNeedStackProtection(needStackProtection)
-  }
-
-  func set(thunkKind: ThunkKind, _ context: FunctionPassContext) {
-    context.notifyEffectsChanged()
-    switch thunkKind {
-    case .noThunk:                 bridged.setThunk(.IsNotThunk)
-    case .thunk:                   bridged.setThunk(.IsThunk)
-    case .reabstractionThunk:      bridged.setThunk(.IsReabstractionThunk)
-    case .signatureOptimizedThunk: bridged.setThunk(.IsSignatureOptimizedThunk)
-    }
-  }
-
-  func set(isPerformanceConstraint: Bool, _ context: FunctionPassContext) {
-    context.notifyEffectsChanged()
-    bridged.setIsPerformanceConstraint(isPerformanceConstraint)
-  }
-
-  func fixStackNesting(_ context: FunctionPassContext) {
-    context._bridged.fixStackNesting(bridged)
-  }
-
-  func appendNewBlock(_ context: FunctionPassContext) -> BasicBlock {
-    context.notifyBranchesChanged()
-    return context._bridged.appendBlock(bridged).block
-  }
-}
-
-extension DeclRef {
-  func calleesAreStaticallyKnowable(_ context: some Context) -> Bool {
-    context._bridged.calleesAreStaticallyKnowable(bridged)
-  }
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/PassManager/ContextCommon.swift b/SwiftCompilerSources/Sources/Optimizer/PassManager/ContextCommon.swift
new file mode 100644
index 0000000000000..2d131b3ac20e2
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/PassManager/ContextCommon.swift
@@ -0,0 +1,168 @@
+//===--- Context.swift - defines the context types ------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import AST
+import SIL
+import OptimizerBridging
+
+extension Context {
+  var bridgedPassContext: BridgedPassContext {
+    BridgedPassContext(_bridged)
+  }
+
+  var options: Options { Options(_bridged: bridgedPassContext) }
+
+  var diagnosticEngine: DiagnosticEngine {
+    return DiagnosticEngine(bridged: bridgedPassContext.getDiagnosticEngine())
+  }
+
+  // The calleeAnalysis is not specific to a function and therefore can be provided in
+  // all contexts.
+  var calleeAnalysis: CalleeAnalysis {
+    let bridgeCA = bridgedPassContext.getCalleeAnalysis()
+    return CalleeAnalysis(bridged: bridgeCA)
+  }
+
+  var hadError: Bool { bridgedPassContext.hadError() }
+
+  /// Enable diagnostics requiring WMO (for @noLocks, @noAllocation
+  /// annotations, Embedded Swift, and class specialization). SourceKit is the
+  /// only consumer that has this disabled today (as it disables WMO
+  /// explicitly).
+  var enableWMORequiredDiagnostics: Bool {
+    bridgedPassContext.enableWMORequiredDiagnostics()
+  }
+
+  func canMakeStaticObjectReadOnly(objectType: Type) -> Bool {
+    bridgedPassContext.canMakeStaticObjectReadOnly(objectType.bridged)
+  }
+}
+
+extension MutatingContext {
+  func notifyInvalidatedStackNesting() { bridgedPassContext.notifyInvalidatedStackNesting() }
+  var needFixStackNesting: Bool { bridgedPassContext.getNeedFixStackNesting() }
+
+  func tryOptimizeApplyOfPartialApply(closure: PartialApplyInst) -> Bool {
+    if bridgedPassContext.tryOptimizeApplyOfPartialApply(closure.bridged) {
+      notifyInstructionsChanged()
+      notifyCallsChanged()
+
+      for use in closure.callee.uses {
+        if use.instruction is FullApplySite {
+          notifyInstructionChanged(use.instruction)
+        }
+      }
+      return true
+    }
+    return false
+  }
+
+  func tryDeleteDeadClosure(closure: SingleValueInstruction, needKeepArgsAlive: Bool = true) -> Bool {
+    if bridgedPassContext.tryDeleteDeadClosure(closure.bridged, needKeepArgsAlive) {
+      notifyInstructionsChanged()
+      return true
+    }
+    return false
+  }
+
+  func tryDevirtualize(apply: FullApplySite, isMandatory: Bool) -> ApplySite? {
+    let result = bridgedPassContext.tryDevirtualizeApply(apply.bridged, isMandatory)
+    if let newApply = result.newApply.instruction {
+      erase(instruction: apply)
+      notifyInstructionsChanged()
+      notifyCallsChanged()
+      if result.cfgChanged {
+        notifyBranchesChanged()
+      }
+      notifyInstructionChanged(newApply)
+      return newApply as! FullApplySite
+    }
+    return nil
+  }
+  
+  func tryOptimizeKeypath(apply: FullApplySite) -> Bool {
+    return bridgedPassContext.tryOptimizeKeypath(apply.bridged)
+  }
+
+  func inlineFunction(apply: FullApplySite, mandatoryInline: Bool) {
+    // This is only a best-effort attempt to notify the new cloned instructions as changed.
+    // TODO: get a list of cloned instructions from the `inlineFunction`
+    let instBeforeInlining = apply.previous
+    let instAfterInlining: Instruction?
+    switch apply {
+    case is ApplyInst:
+      instAfterInlining = apply.next
+    case let beginApply as BeginApplyInst:
+      let next = beginApply.next!
+      instAfterInlining = (next is EndApplyInst ? nil : next)
+    case is TryApplyInst:
+      instAfterInlining = apply.parentBlock.next?.instructions.first
+    default:
+      instAfterInlining = nil
+    }
+
+    bridgedPassContext.inlineFunction(apply.bridged, mandatoryInline)
+
+    if let instBeforeInlining = instBeforeInlining?.next,
+       let instAfterInlining = instAfterInlining,
+       !instAfterInlining.isDeleted {
+      notifyNewInstructions(from: instBeforeInlining, to: instAfterInlining)
+    }
+  }
+
+  func loadFunction(function: Function, loadCalleesRecursively: Bool) -> Bool {
+    if function.isDefinition {
+      return true
+    }
+    _bridged.loadFunction(function.bridged, loadCalleesRecursively)
+    return function.isDefinition
+  }
+
+  private func notifyNewInstructions(from: Instruction, to: Instruction) {
+    var inst = from
+    while inst != to {
+      if !inst.isDeleted {
+        notifyInstructionChanged(inst)
+      }
+      if let next = inst.next {
+        inst = next
+      } else {
+        inst = inst.parentBlock.next!.instructions.first!
+      }
+    }
+  }
+
+  func getContextSubstitutionMap(for type: Type) -> SubstitutionMap {
+    SubstitutionMap(bridged: _bridged.getContextSubstitutionMap(type.bridged))
+  }
+
+  /// Notifies the pass manager that the optimization result of the current pass depends
+  /// on the body (i.e. SIL instructions) of another function than the currently optimized one.
+  func notifyDependency(onBodyOf otherFunction: Function) {
+    bridgedPassContext.notifyDependencyOnBodyOf(otherFunction.bridged)
+  }
+}
+
+extension Instruction {
+  var arraySemanticsCallKind: ArrayCallKind {
+    return BridgedPassContext.getArraySemanticsCallKind(self.bridged)
+  }
+
+  func canHoistArraySemanticsCall(to toInst: Instruction, _ context: FunctionPassContext) -> Bool {
+    return context.bridgedPassContext.canHoistArraySemanticsCall(self.bridged, toInst.bridged)
+  }
+
+  func hoistArraySemanticsCall(before toInst: Instruction, _ context: some MutatingContext) {
+    context.bridgedPassContext.hoistArraySemanticsCall(self.bridged, toInst.bridged) // Internally updates dom tree.
+    context.notifyInstructionsChanged()
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/PassManager/FunctionPassContext.swift b/SwiftCompilerSources/Sources/Optimizer/PassManager/FunctionPassContext.swift
new file mode 100644
index 0000000000000..f2ec4f144b889
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/PassManager/FunctionPassContext.swift
@@ -0,0 +1,197 @@
+//===--- FunctionPassContext.swift ----------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import AST
+import SIL
+import OptimizerBridging
+
+/// The context which is passed to the run-function of a FunctionPass.
+struct FunctionPassContext : MutatingContext {
+  let _bridged: BridgedContext
+
+  // A no-op.
+  var notifyInstructionChanged: (Instruction) -> () { return { inst in } }
+
+  func continueWithNextSubpassRun(for inst: Instruction? = nil) -> Bool {
+    return bridgedPassContext.continueWithNextSubpassRun(inst.bridged)
+  }
+
+  func createSimplifyContext(preserveDebugInfo: Bool,
+                             notifyInstructionChanged: @escaping (Instruction) -> ()
+  ) -> SimplifyContext {
+    SimplifyContext(_bridged: _bridged, notifyInstructionChanged: notifyInstructionChanged,
+                    preserveDebugInfo: preserveDebugInfo)
+  }
+
+  var deadEndBlocks: DeadEndBlocksAnalysis {
+    let bridgeDEA = bridgedPassContext.getDeadEndBlocksAnalysis()
+    return DeadEndBlocksAnalysis(bridged: bridgeDEA)
+  }
+
+  var dominatorTree: DominatorTree {
+    let bridgedDT = bridgedPassContext.getDomTree()
+    return DominatorTree(bridged: bridgedDT)
+  }
+
+  var postDominatorTree: PostDominatorTree {
+    let bridgedPDT = bridgedPassContext.getPostDomTree()
+    return PostDominatorTree(bridged: bridgedPDT)
+  }
+  
+  var loopTree: LoopTree {
+    let bridgedLT = bridgedPassContext.getLoopTree()
+    return LoopTree(bridged: bridgedLT, context: self)
+  }
+
+  func notifyNewFunction(function: Function, derivedFrom: Function) {
+    bridgedPassContext.addFunctionToPassManagerWorklist(function.bridged, derivedFrom.bridged)
+  }
+
+  func loadFunction(name: StaticString, loadCalleesRecursively: Bool) -> Function? {
+    return name.withUTF8Buffer { (nameBuffer: UnsafeBufferPointer<UInt8>) in
+      let nameStr = BridgedStringRef(data: nameBuffer.baseAddress, count: nameBuffer.count)
+      return _bridged.loadFunction(nameStr, loadCalleesRecursively).function
+    }
+  }
+
+  func eliminateDeadAllocations(in function: Function) -> Bool {
+    if bridgedPassContext.eliminateDeadAllocations(function.bridged) {
+      notifyInstructionsChanged()
+      return true
+    }
+    return false
+  }
+
+  func specializeClassMethodInst(_ cm: ClassMethodInst) -> Bool {
+    if bridgedPassContext.specializeClassMethodInst(cm.bridged) {
+      notifyInstructionsChanged()
+      notifyCallsChanged()
+      return true
+    }
+    return false
+  }
+
+  func specializeWitnessMethodInst(_ wm: WitnessMethodInst) -> Bool {
+    if bridgedPassContext.specializeWitnessMethodInst(wm.bridged) {
+      notifyInstructionsChanged()
+      notifyCallsChanged()
+      return true
+    }
+    return false
+  }
+
+  func specializeApplies(in function: Function, isMandatory: Bool) -> Bool {
+    if bridgedPassContext.specializeAppliesInFunction(function.bridged, isMandatory) {
+      notifyInstructionsChanged()
+      notifyCallsChanged()
+      return true
+    }
+    return false
+  }
+
+  func specialize(function: Function,
+                  for substitutions: SubstitutionMap,
+                  convertIndirectToDirect: Bool,
+                  isMandatory: Bool
+  ) -> Function? {
+    return bridgedPassContext.specializeFunction(function.bridged, substitutions.bridged,
+                                                 convertIndirectToDirect, isMandatory).function
+  }
+
+  func mangleOutlinedVariable(from function: Function) -> String {
+    return String(taking: bridgedPassContext.mangleOutlinedVariable(function.bridged))
+  }
+
+  enum ClosureArgumentMangling {
+    case closure(SingleValueInstruction)
+
+    /// The argument specializes for the same closure as a previous argument, e.g.
+    /// ```
+    ///   %1 = partial_apply %closure
+    ///   apply %f(%1, %1)    // first argument: `.closure(%1)`
+    ///                       // second argument: `.previousArgumentIndex(0)`
+    case previousArgumentIndex(Int)
+  }
+
+  func mangle(withClosureArguments closureArgs: [(argumentIndex: Int, argumentValue: ClosureArgumentMangling)],
+              from applySiteCallee: Function
+  ) -> String {
+    let bridgedArgManglings = closureArgs.map {
+      switch $0.argumentValue {
+      case .closure(let closure):
+        return BridgedPassContext.ClosureArgMangling(argIdx: $0.argumentIndex,
+                                                     inst: Optional<Instruction>(closure).bridged,
+                                                     otherArgIdx: -1)
+      case .previousArgumentIndex(let idx):
+        return BridgedPassContext.ClosureArgMangling(argIdx: $0.argumentIndex,
+                                                     inst: OptionalBridgedInstruction(),
+                                                     otherArgIdx: idx)
+      }
+    }
+
+    return bridgedArgManglings.withBridgedArrayRef{ bridgedClosureArgs in
+      String(taking: bridgedPassContext.mangleWithClosureArgs(bridgedClosureArgs, applySiteCallee.bridged))
+    }
+  }
+
+  func mangle(withConstantCaptureArguments constArgs: [(argumentIndex: Int, argument: Value)],
+              from applySiteCallee: Function
+  ) -> String {
+    let bridgedConstArgs = constArgs.map { ($0.argumentIndex, $0.argument.bridged) }
+    return bridgedConstArgs.withBridgedArrayRef{ bridgedConstArgsArray in
+      String(taking: bridgedPassContext.mangleWithConstCaptureArgs(bridgedConstArgsArray, applySiteCallee.bridged))
+    }
+  }
+
+  func mangle(withBoxToStackPromotedArguments argIndices: [Int], from original: Function) -> String {
+    argIndices.withBridgedArrayRef { bridgedArgIndices in
+      String(taking: bridgedPassContext.mangleWithBoxToStackPromotedArgs(bridgedArgIndices, original.bridged))
+    }
+  }
+
+  func createSpecializedFunctionDeclaration(from original: Function, withName specializedFunctionName: String,
+                                            withParams specializedParameters: [ParameterInfo],
+                                            makeThin: Bool = false,
+                                            makeBare: Bool = false,
+                                            preserveGenericSignature: Bool = true) -> Function
+  {
+    return specializedFunctionName._withBridgedStringRef { nameRef in
+      let bridgedParamInfos = specializedParameters.map { $0._bridged }
+
+      return bridgedParamInfos.withUnsafeBufferPointer { paramBuf in
+        bridgedPassContext.createSpecializedFunctionDeclaration(nameRef, paramBuf.baseAddress, paramBuf.count,
+                                                                original.bridged, makeThin, makeBare,
+                                                                preserveGenericSignature).function
+      }
+    }
+  }
+
+  func buildSpecializedFunction<T>(specializedFunction: Function, buildFn: (Function, FunctionPassContext) -> T) -> T {
+    let nestedBridgedContext = bridgedPassContext.initializeNestedPassContext(specializedFunction.bridged)
+    let nestedContext = FunctionPassContext(_bridged: nestedBridgedContext)
+    defer { bridgedPassContext.deinitializedNestedPassContext() }
+
+    return buildFn(specializedFunction, nestedContext)
+  }
+
+  /// Makes sure that the lifetime of `value` ends at all control flow paths, even in dead-end blocks.
+  /// Inserts destroys in dead-end blocks if those are missing.
+  func completeLifetime(of value: Value) {
+    if bridgedPassContext.completeLifetime(value.bridged) {
+      notifyInstructionsChanged()
+    }
+  }
+
+  func fixStackNesting(in function: Function) {
+    bridgedPassContext.fixStackNesting(function.bridged)
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/PassManager/ModulePassContext.swift b/SwiftCompilerSources/Sources/Optimizer/PassManager/ModulePassContext.swift
index 7a1e9f39354f8..9042bbbb1ce5b 100644
--- a/SwiftCompilerSources/Sources/Optimizer/PassManager/ModulePassContext.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/PassManager/ModulePassContext.swift
@@ -20,7 +20,7 @@ import OptimizerBridging
 /// but it doesn't provide any APIs to modify functions.
 /// In order to modify a function, a module pass must use `transform(function:)`.
 struct ModulePassContext : Context, CustomStringConvertible {
-  let _bridged: BridgedPassContext
+  let _bridged: BridgedContext
 
   var description: String {
     return String(taking: _bridged.getModuleDescription())
@@ -95,21 +95,21 @@ struct ModulePassContext : Context, CustomStringConvertible {
   }
 
   var functions: FunctionList {
-    FunctionList(first: _bridged.getFirstFunctionInModule().function)
+    FunctionList(first: bridgedPassContext.getFirstFunctionInModule().function)
   }
   
   var globalVariables: GlobalVariableList {
-    GlobalVariableList(first: _bridged.getFirstGlobalInModule().globalVar)
+    GlobalVariableList(first: bridgedPassContext.getFirstGlobalInModule().globalVar)
   }
 
-  var vTables: VTableArray { VTableArray(bridgedCtxt: _bridged) }
+  var vTables: VTableArray { VTableArray(bridgedCtxt: bridgedPassContext) }
   
   var witnessTables: WitnessTableList {
-    WitnessTableList(first: _bridged.getFirstWitnessTableInModule().witnessTable)
+    WitnessTableList(first: bridgedPassContext.getFirstWitnessTableInModule().witnessTable)
   }
 
   var defaultWitnessTables: DefaultWitnessTableList {
-    DefaultWitnessTableList(first: _bridged.getFirstDefaultWitnessTableInModule().defaultWitnessTable)
+    DefaultWitnessTableList(first: bridgedPassContext.getFirstDefaultWitnessTableInModule().defaultWitnessTable)
   }
 
   /// Run a closure with a `PassContext` for a function, which allows to modify that function.
@@ -117,9 +117,10 @@ struct ModulePassContext : Context, CustomStringConvertible {
   /// Only a single `transform` can be alive at the same time, i.e. it's not allowed to nest
   /// calls to `transform`.
   func transform(function: Function, _ runOnFunction: (FunctionPassContext) -> ()) {
-    _bridged.beginTransformFunction(function.bridged)
-    runOnFunction(FunctionPassContext(_bridged: _bridged))
-    _bridged.endTransformFunction();
+    let nestedBridgedContext = bridgedPassContext.initializeNestedPassContext(function.bridged)
+    let nestedContext = FunctionPassContext(_bridged: nestedBridgedContext)
+    runOnFunction(nestedContext)
+    bridgedPassContext.deinitializedNestedPassContext()
   }
 
   func loadFunction(function: Function, loadCalleesRecursively: Bool) -> Bool {
@@ -130,8 +131,13 @@ struct ModulePassContext : Context, CustomStringConvertible {
     return function.isDefinition
   }
 
-  func specialize(function: Function, for substitutions: SubstitutionMap) -> Function? {
-    return _bridged.specializeFunction(function.bridged, substitutions.bridged).function
+  func specialize(function: Function,
+                  for substitutions: SubstitutionMap,
+                  convertIndirectToDirect: Bool,
+                  isMandatory: Bool
+  ) -> Function? {
+    return bridgedPassContext.specializeFunction(function.bridged, substitutions.bridged,
+                                                 convertIndirectToDirect, isMandatory).function
   }
 
   enum DeserializationMode {
@@ -140,18 +146,18 @@ struct ModulePassContext : Context, CustomStringConvertible {
   }
 
   func deserializeAllCallees(of function: Function, mode: DeserializationMode) {
-    _bridged.deserializeAllCallees(function.bridged, mode == .allFunctions ? true : false)
+    bridgedPassContext.deserializeAllCallees(function.bridged, mode == .allFunctions ? true : false)
   }
 
   @discardableResult
-  func createWitnessTable(entries: [WitnessTable.Entry],
+  func createSpecializedWitnessTable(entries: [WitnessTable.Entry],
                           conformance: Conformance,
                           linkage: Linkage,
                           serialized: Bool) -> WitnessTable
   {
     let bridgedEntries = entries.map { $0.bridged }
     let bridgedWitnessTable = bridgedEntries.withBridgedArrayRef {
-      _bridged.createWitnessTable(linkage.bridged, serialized, conformance.bridged, $0)
+      _bridged.createSpecializedWitnessTable(linkage.bridged, serialized, conformance.bridged, $0)
     }
     return WitnessTable(bridged: bridgedWitnessTable)
   }
@@ -197,21 +203,21 @@ struct ModulePassContext : Context, CustomStringConvertible {
   }
 
   func mangleAsyncRemoved(from function: Function) -> String {
-    return String(taking: _bridged.mangleAsyncRemoved(function.bridged))
+    return String(taking: bridgedPassContext.mangleAsyncRemoved(function.bridged))
   }
 
   func mangle(withDeadArguments: [Int], from function: Function) -> String {
-    withDeadArguments.withUnsafeBufferPointer { bufPtr in
-      bufPtr.withMemoryRebound(to: Int.self) { valPtr in
-        String(taking: _bridged.mangleWithDeadArgs(valPtr.baseAddress,
-                                                   withDeadArguments.count,
-                                                   function.bridged))
-      }
+    withDeadArguments.withBridgedArrayRef { bridgedArgIndices in
+      String(taking: bridgedPassContext.mangleWithDeadArgs(bridgedArgIndices, function.bridged))
     }
   }
 
+  func erase(function: Function) {
+    bridgedPassContext.eraseFunction(function.bridged)
+  }
+
   func notifyFunctionTablesChanged() {
-    _bridged.asNotificationHandler().notifyChanges(.functionTablesChanged)
+    _bridged.notifyChanges(.FunctionTables)
   }
 }
 
diff --git a/SwiftCompilerSources/Sources/Optimizer/PassManager/Options.swift b/SwiftCompilerSources/Sources/Optimizer/PassManager/Options.swift
index 81bd6a999cdb3..2c4b9d031f3d2 100644
--- a/SwiftCompilerSources/Sources/Optimizer/PassManager/Options.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/PassManager/Options.swift
@@ -36,8 +36,12 @@ struct Options {
     _bridged.enableAddressDependencies()
   }
 
+  var noAllocations: Bool {
+    _bridged.noAllocations()
+  }
+
   var enableEmbeddedSwift: Bool {
-    _bridged.hasFeature(.Embedded)
+    hasFeature(.Embedded)
   }
 
   var enableMergeableTraps: Bool {
diff --git a/SwiftCompilerSources/Sources/Optimizer/PassManager/PassRegistration.swift b/SwiftCompilerSources/Sources/Optimizer/PassManager/PassRegistration.swift
index 48c7482a59a56..e92268b384e49 100644
--- a/SwiftCompilerSources/Sources/Optimizer/PassManager/PassRegistration.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/PassManager/PassRegistration.swift
@@ -17,16 +17,15 @@ import OptimizerBridging
 @_cdecl("initializeSwiftModules")
 public func initializeSwiftModules() {
   registerAST()
-  registerSILClasses()
+  registerSIL()
   registerSwiftAnalyses()
-  registerUtilities()
   registerSwiftPasses()
   registerOptimizerTests()
 }
 
 private func registerPass(
       _ pass: ModulePass,
-      _ runFn: @escaping (@convention(c) (BridgedPassContext) -> ())) {
+      _ runFn: @escaping (@convention(c) (BridgedContext) -> ())) {
   pass.name._withBridgedStringRef { nameStr in
     SILPassManager_registerModulePass(nameStr, runFn)
   }
@@ -63,16 +62,20 @@ private func registerForSILCombine<InstType: SILCombineSimplifiable>(
 
 private func registerSwiftPasses() {
   // Module passes
+  registerPass(mandatoryAllocBoxToStack, { mandatoryAllocBoxToStack.run($0) })
   registerPass(mandatoryPerformanceOptimizations, { mandatoryPerformanceOptimizations.run($0) })
   registerPass(diagnoseUnknownConstValues, { diagnoseUnknownConstValues.run($0)})
   registerPass(readOnlyGlobalVariablesPass, { readOnlyGlobalVariablesPass.run($0) })
   registerPass(stackProtection, { stackProtection.run($0) })
+  registerPass(embeddedSwiftDiagnostics, { embeddedSwiftDiagnostics.run($0) })
 
   // Function passes
+  registerPass(allocBoxToStack, { allocBoxToStack.run($0) })
   registerPass(asyncDemotion, { asyncDemotion.run($0) })
   registerPass(booleanLiteralFolding, { booleanLiteralFolding.run($0) })
   registerPass(letPropertyLowering, { letPropertyLowering.run($0) })
   registerPass(mergeCondFailsPass, { mergeCondFailsPass.run($0) })
+  registerPass(constantCapturePropagation, { constantCapturePropagation.run($0) })
   registerPass(computeEscapeEffects, { computeEscapeEffects.run($0) })
   registerPass(computeSideEffects, { computeSideEffects.run($0) })
   registerPass(diagnoseInfiniteRecursion, { diagnoseInfiniteRecursion.run($0) })
@@ -99,14 +102,20 @@ private func registerSwiftPasses() {
   registerPass(lifetimeDependenceInsertionPass, { lifetimeDependenceInsertionPass.run($0) })
   registerPass(lifetimeDependenceScopeFixupPass, { lifetimeDependenceScopeFixupPass.run($0) })
   registerPass(copyToBorrowOptimization, { copyToBorrowOptimization.run($0) })
-  registerPass(generalClosureSpecialization, { generalClosureSpecialization.run($0) })
+  registerPass(tempRValueElimination, { tempRValueElimination.run($0) })
+  registerPass(mandatoryTempRValueElimination, { mandatoryTempRValueElimination.run($0) })
+  registerPass(tempLValueElimination, { tempLValueElimination.run($0) })
+  registerPass(closureSpecialization, { closureSpecialization.run($0) })
   registerPass(autodiffClosureSpecialization, { autodiffClosureSpecialization.run($0) })
+  registerPass(loopInvariantCodeMotionPass, { loopInvariantCodeMotionPass.run($0) })
 
   // Instruction passes
   registerForSILCombine(BeginBorrowInst.self,      { run(BeginBorrowInst.self, $0) })
   registerForSILCombine(BeginCOWMutationInst.self, { run(BeginCOWMutationInst.self, $0) })
+  registerForSILCombine(BuiltinInst.self,          { run(BuiltinInst.self, $0) })
   registerForSILCombine(FixLifetimeInst.self,      { run(FixLifetimeInst.self, $0) })
   registerForSILCombine(GlobalValueInst.self,      { run(GlobalValueInst.self, $0) })
+  registerForSILCombine(StructInst.self,           { run(StructInst.self, $0) })
   registerForSILCombine(StrongRetainInst.self,     { run(StrongRetainInst.self, $0) })
   registerForSILCombine(StrongReleaseInst.self,    { run(StrongReleaseInst.self, $0) })
   registerForSILCombine(RetainValueInst.self,      { run(RetainValueInst.self, $0) })
@@ -114,18 +123,23 @@ private func registerSwiftPasses() {
   registerForSILCombine(LoadInst.self,             { run(LoadInst.self, $0) })
   registerForSILCombine(LoadBorrowInst.self,       { run(LoadBorrowInst.self, $0) })
   registerForSILCombine(CopyValueInst.self,        { run(CopyValueInst.self, $0) })
+  registerForSILCombine(CopyBlockInst.self,        { run(CopyBlockInst.self, $0) })
   registerForSILCombine(DestroyValueInst.self,     { run(DestroyValueInst.self, $0) })
   registerForSILCombine(DestructureStructInst.self, { run(DestructureStructInst.self, $0) })
   registerForSILCombine(DestructureTupleInst.self, { run(DestructureTupleInst.self, $0) })
   registerForSILCombine(TypeValueInst.self, { run(TypeValueInst.self, $0) })
   registerForSILCombine(ClassifyBridgeObjectInst.self, { run(ClassifyBridgeObjectInst.self, $0) })
+  registerForSILCombine(MarkDependenceInst.self,    { run(MarkDependenceInst.self, $0) })
+  registerForSILCombine(MarkDependenceAddrInst.self, { run(MarkDependenceAddrInst.self, $0) })
   registerForSILCombine(PointerToAddressInst.self,  { run(PointerToAddressInst.self, $0) })
   registerForSILCombine(UncheckedEnumDataInst.self, { run(UncheckedEnumDataInst.self, $0) })
   registerForSILCombine(WitnessMethodInst.self,     { run(WitnessMethodInst.self, $0) })
+  registerForSILCombine(UncheckedAddrCastInst.self, { run(UncheckedAddrCastInst.self, $0) })
   registerForSILCombine(UnconditionalCheckedCastInst.self, { run(UnconditionalCheckedCastInst.self, $0) })
   registerForSILCombine(AllocStackInst.self,        { run(AllocStackInst.self, $0) })
   registerForSILCombine(ApplyInst.self,             { run(ApplyInst.self, $0) })
   registerForSILCombine(TryApplyInst.self,          { run(TryApplyInst.self, $0) })
+  registerForSILCombine(EndCOWMutationAddrInst.self, { run(EndCOWMutationAddrInst.self, $0) })
 
   // Test passes
   registerPass(aliasInfoDumper, { aliasInfoDumper.run($0) })
@@ -137,7 +151,6 @@ private func registerSwiftPasses() {
   registerPass(deadEndBlockDumper, { deadEndBlockDumper.run($0) })
   registerPass(memBehaviorDumper, { memBehaviorDumper.run($0) })
   registerPass(rangeDumper, { rangeDumper.run($0) })
-  registerPass(runUnitTests, { runUnitTests.run($0) })
   registerPass(testInstructionIteration, { testInstructionIteration.run($0) })
   registerPass(updateBorrowedFromPass, { updateBorrowedFromPass.run($0) })
 }
@@ -146,8 +159,3 @@ private func registerSwiftAnalyses() {
   AliasAnalysis.register()
   CalleeAnalysis.register()
 }
-
-private func registerUtilities() {
-  registerVerifier()
-  registerPhiUpdater()
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/PassManager/Passes.swift b/SwiftCompilerSources/Sources/Optimizer/PassManager/Passes.swift
index 0e9841bdf55cf..87541053e962b 100644
--- a/SwiftCompilerSources/Sources/Optimizer/PassManager/Passes.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/PassManager/Passes.swift
@@ -39,7 +39,7 @@ struct ModulePass {
     self.runFunction = runFunction
   }
 
-  func run(_ bridgedCtxt: BridgedPassContext) {
+  func run(_ bridgedCtxt: BridgedContext) {
     let context = ModulePassContext(_bridged: bridgedCtxt)
     runFunction(context)
   }
diff --git a/SwiftCompilerSources/Sources/Optimizer/PassManager/SimplifyContext.swift b/SwiftCompilerSources/Sources/Optimizer/PassManager/SimplifyContext.swift
new file mode 100644
index 0000000000000..2c9b133f4d7e7
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/PassManager/SimplifyContext.swift
@@ -0,0 +1,43 @@
+//===--- SimplifyContext.swift --------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+import OptimizerBridging
+
+struct SimplifyContext : MutatingContext {
+  let _bridged: BridgedContext
+  let notifyInstructionChanged: (Instruction) -> ()
+  let preserveDebugInfo: Bool
+
+  func constantFold(builtin: BuiltinInst) -> Value? {
+    bridgedPassContext.constantFoldBuiltin(builtin.bridged).value
+  }
+}
+
+// Those Type APIs get information from IRGenModule, so they are formally not part of SIL and
+// therefore need to be defined here, in the Optimizer module.
+extension Type {
+  func getStaticSize(context: SimplifyContext) -> Int? {
+    let v = context.bridgedPassContext.getStaticSize(self.bridged)
+    return v == -1 ? nil : v
+  }
+
+  func getStaticAlignment(context: SimplifyContext) -> Int? {
+    let v = context.bridgedPassContext.getStaticAlignment(self.bridged)
+    return v == -1 ? nil : v
+  }
+
+  func getStaticStride(context: SimplifyContext) -> Int? {
+    let v = context.bridgedPassContext.getStaticStride(self.bridged)
+    return v == -1 ? nil : v
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/TestPasses/CMakeLists.txt b/SwiftCompilerSources/Sources/Optimizer/TestPasses/CMakeLists.txt
index 6596426f53102..2aed2909f8708 100644
--- a/SwiftCompilerSources/Sources/Optimizer/TestPasses/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/Optimizer/TestPasses/CMakeLists.txt
@@ -15,6 +15,6 @@ swift_compiler_sources(Optimizer
   MemBehaviorDumper.swift
   SILPrinter.swift
   RangeDumper.swift
-  RunUnitTests.swift
+  UpdateBorrowedFrom.swift
   TestInstructionIteration.swift
 )
diff --git a/SwiftCompilerSources/Sources/Optimizer/TestPasses/EscapeInfoDumper.swift b/SwiftCompilerSources/Sources/Optimizer/TestPasses/EscapeInfoDumper.swift
index 873ba9bac330e..d13427a94c5c9 100644
--- a/SwiftCompilerSources/Sources/Optimizer/TestPasses/EscapeInfoDumper.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/TestPasses/EscapeInfoDumper.swift
@@ -109,7 +109,7 @@ let addressEscapeInfoDumper = FunctionPass(name: "dump-addr-escape-info") {
   for value in valuesToCheck {
     print("value:\(value)")
     for apply in applies {
-      if value.allContainedAddresss.isEscaping(using: Visitor(apply: apply), context) {
+      if value.allContainedAddresses.isEscaping(using: Visitor(apply: apply), context) {
         print("  ==> \(apply)")
       } else {
         print("  -   \(apply)")
@@ -127,8 +127,8 @@ let addressEscapeInfoDumper = FunctionPass(name: "dump-addr-escape-info") {
         print(lhs)
         print(rhs)
 
-        let projLhs = lhs.allContainedAddresss
-        let projRhs = rhs.allContainedAddresss
+        let projLhs = lhs.allContainedAddresses
+        let projRhs = rhs.allContainedAddresses
         let mayAlias = projLhs.canAddressAlias(with: projRhs, context)
         if mayAlias != projRhs.canAddressAlias(with: projLhs, context) {
           fatalError("canAddressAlias(with:) must be symmetric")
diff --git a/SwiftCompilerSources/Sources/Optimizer/TestPasses/MemBehaviorDumper.swift b/SwiftCompilerSources/Sources/Optimizer/TestPasses/MemBehaviorDumper.swift
index d7b352454d9fa..7def70e95934d 100644
--- a/SwiftCompilerSources/Sources/Optimizer/TestPasses/MemBehaviorDumper.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/TestPasses/MemBehaviorDumper.swift
@@ -63,6 +63,7 @@ private extension Instruction {
          is BeginAccessInst,
          is EndAccessInst,
          is EndCOWMutationInst,
+         is EndCOWMutationAddrInst,
          is CopyValueInst,
          is DestroyValueInst,
          is StrongReleaseInst,
diff --git a/SwiftCompilerSources/Sources/Optimizer/TestPasses/RunUnitTests.swift b/SwiftCompilerSources/Sources/Optimizer/TestPasses/RunUnitTests.swift
deleted file mode 100644
index 9e995aba5a300..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/TestPasses/RunUnitTests.swift
+++ /dev/null
@@ -1,24 +0,0 @@
-//===--- UnitTests.swift - A pseudo pass for running the unit tests -------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import SIL
-
-/// This pass should only be used by sil-opt to run all the unit tests.
-///
-let runUnitTests = ModulePass(name: "run-unit-tests") {
-    (context: ModulePassContext) in
-
-  print("--- Run unit tests ---")
-  
-  print("test ProjectionPath")
-  SmallProjectionPath.runUnitTests()
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/TestPasses/UpdateBorrowedFrom.swift b/SwiftCompilerSources/Sources/Optimizer/TestPasses/UpdateBorrowedFrom.swift
new file mode 100644
index 0000000000000..e6fd49f408fca
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/TestPasses/UpdateBorrowedFrom.swift
@@ -0,0 +1,22 @@
+//===--- PhiUpdater.swift -------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+
+/// This pass is only used for testing.
+/// In the regular pipeline it's not needed because optimization passes must make sure that borrowed-from
+/// instructions are updated once the pass finishes.
+let updateBorrowedFromPass = FunctionPass(name: "update-borrowed-from") {
+  (function: Function, context: FunctionPassContext) in
+
+  updateBorrowedFrom(in: function, context)
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/AccessUtilsTest.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/AccessUtilsTest.swift
deleted file mode 100644
index 99014c26243ee..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/AccessUtilsTest.swift
+++ /dev/null
@@ -1,23 +0,0 @@
-//===--- AccessUtils.swift - Utilities for analyzing memory accesses ------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-//
-// TODO: Move this to AccessUtils.swift when FunctionTest is available.
-//
-//===----------------------------------------------------------------------===//
-
-let getAccessBaseTest = FunctionTest("swift_get_access_base") {
-  function, arguments, context in
-  let address = arguments.takeValue()
-  print("Address: \(address)")
-  let base = address.accessBase
-  print("Base: \(base)")
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/AddressUtils.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/AddressUtils.swift
index 40bd631f5d0b2..3f1b5b50cea8b 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/AddressUtils.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/AddressUtils.swift
@@ -125,13 +125,13 @@ extension AddressUseVisitor {
     case is SwitchEnumAddrInst, is CheckedCastAddrBranchInst,
          is SelectEnumAddrInst, is InjectEnumAddrInst,
          is StoreInst, is StoreUnownedInst, is StoreWeakInst,
-         is AssignInst, is AssignByWrapperInst, is AssignOrInitInst,
+         is AssignInst, is AssignOrInitInst,
          is TupleAddrConstructorInst, is InitBlockStorageHeaderInst,
          is RetainValueAddrInst, is ReleaseValueAddrInst,
          is DestroyAddrInst, is DeallocStackInst, 
          is DeinitExistentialAddrInst,
          is IsUniqueInst, is MarkFunctionEscapeInst,
-         is PackElementSetInst:
+         is PackElementSetInst, is EndCOWMutationAddrInst:
       return leafAddressUse(of: operand)
 
     case is LoadInst, is LoadUnownedInst,  is LoadWeakInst, is ValueMetatypeInst, is ExistentialMetatypeInst,
@@ -159,7 +159,7 @@ extension AddressUseVisitor {
            .GenericFDiv, .GenericMul, .GenericFMul, .GenericSDiv,
            .GenericExactSDiv, .GenericShl, .GenericSRem, .GenericSub,
            .GenericFSub, .GenericUDiv, .GenericExactUDiv, .GenericURem,
-           .GenericFRem, .GenericXor, .TaskRunInline, .ZeroInitializer,
+           .GenericFRem, .GenericXor, .TaskRunInline, .ZeroInitializer, .PrepareInitialization,
            .GetEnumTag, .InjectEnumTag:
         return leafAddressUse(of: operand)
       default:
@@ -501,6 +501,11 @@ enum AddressOwnershipLiveRange : CustomStringConvertible {
     }
   }
 
+  /// Return the live range of the addressable value that reaches 'begin', not including 'begin', which may itself be an
+  /// access of the address.
+  ///
+  /// The range ends at the destroy or reassignment of the addressable value.
+  ///
   /// Return nil if the live range is unknown.
   static func compute(for address: Value, at begin: Instruction,
                       _ localReachabilityCache: LocalVariableReachabilityCache,
@@ -624,7 +629,7 @@ extension AddressOwnershipLiveRange {
     var reachableUses = Stack<LocalVariableAccess>(context)
     defer { reachableUses.deinitialize() }
 
-    localReachability.gatherKnownReachableUses(from: assignment, in: &reachableUses)
+    localReachability.gatherKnownLifetimeUses(from: assignment, in: &reachableUses)
 
     let assignmentInst = assignment.instruction ?? allocation.parentFunction.entryBlock.instructions.first!
     var range = InstructionRange(begin: assignmentInst, context)
@@ -643,12 +648,10 @@ extension AddressOwnershipLiveRange {
 let addressOwnershipLiveRangeTest = FunctionTest("address_ownership_live_range") {
   function, arguments, context in
   let address = arguments.takeValue()
+  let begin = arguments.takeInstruction()
   print("Address: \(address)")
   print("Base: \(address.accessBase)")
-  let begin = address.definingInstructionOrTerminator ?? {
-    assert(address is FunctionArgument)
-    return function.instructions.first!
-  }()
+  print("Begin: \(begin)")
   let localReachabilityCache = LocalVariableReachabilityCache()
   guard var ownershipRange = AddressOwnershipLiveRange.compute(for: address, at: begin,
                                                                localReachabilityCache, context) else {
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/CMakeLists.txt b/SwiftCompilerSources/Sources/Optimizer/Utilities/CMakeLists.txt
index bac67d8c12f3a..35ca4d97aae75 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/CMakeLists.txt
@@ -7,23 +7,14 @@
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 swift_compiler_sources(Optimizer
-  AccessUtilsTest.swift
   AddressUtils.swift
-  BorrowUtils.swift
-  SpecializationCloner.swift
-  DiagnosticEngine.swift
   Devirtualization.swift
   EscapeUtils.swift
-  ForwardingUtils.swift
   FunctionSignatureTransforms.swift
+  FunctionTest.swift
   GenericSpecialization.swift
   LifetimeDependenceUtils.swift
   LocalVariableUtils.swift
   OptUtils.swift
   OwnershipLiveness.swift
-  PhiUpdater.swift
-  SSAUpdater.swift
-  StaticInitCloner.swift
-  Test.swift
-  Verifier.swift
 )
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/Devirtualization.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/Devirtualization.swift
index 6d05399758d53..1eae780d8252d 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/Devirtualization.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/Devirtualization.swift
@@ -28,6 +28,15 @@ func devirtualizeDeinits(of destroy: DestroyAddrInst, _ context: some MutatingCo
   return devirtualize(destroy: destroy, context)
 }
 
+func devirtualizeDeinits(of builtin: BuiltinInst, _ context: some MutatingContext) -> Bool {
+  switch builtin.id {
+  case .DestroyArray:
+    return devirtualize(builtinDestroyArray: builtin, context)
+  default:
+    return true
+  }
+}
+
 private func devirtualize(destroy: some DevirtualizableDestroy, _ context: some MutatingContext) -> Bool {
   let type = destroy.type
   if !type.isMoveOnly {
@@ -254,6 +263,59 @@ extension DestroyAddrInst : DevirtualizableDestroy {
   }
 }
 
+private func devirtualize(builtinDestroyArray: BuiltinInst, _ context: some MutatingContext) -> Bool {
+  let function = builtinDestroyArray.parentFunction
+  let elementType = builtinDestroyArray.substitutionMap.replacementType.loweredType(in: function)
+  guard elementType.isMoveOnly,
+        // This avoids lowering the loop if the element is a non-copyable generic type.
+        (elementType.isStruct || elementType.isEnum)
+  else {
+    return true
+  }
+
+  // Lower the `builtin "destroyArray" to a loop which destroys all elements
+
+  let basePointer = builtinDestroyArray.arguments[1]
+  let arrayCount = builtinDestroyArray.arguments[2]
+  let indexType = arrayCount.type
+  let boolType = context.getBuiltinIntegerType(bitWidth: 1)
+
+  let preheaderBlock = builtinDestroyArray.parentBlock
+  let exitBlock = context.splitBlock(after: builtinDestroyArray)
+  let headerBlock = context.createBlock(after: preheaderBlock)
+  let bodyBlock = context.createBlock(after: headerBlock)
+
+  let preheaderBuilder = Builder(atEndOf: preheaderBlock, location: builtinDestroyArray.location, context)
+  let zero = preheaderBuilder.createIntegerLiteral(0, type: indexType)
+  let one = preheaderBuilder.createIntegerLiteral(1, type: indexType)
+  let falseValue = preheaderBuilder.createBoolLiteral(false);
+  let baseAddress = preheaderBuilder.createPointerToAddress(pointer: basePointer,
+                                                            addressType: elementType.addressType,
+                                                            isStrict: true, isInvariant: false)
+  preheaderBuilder.createBranch(to: headerBlock, arguments: [zero])
+
+  let inductionVariable = headerBlock.addArgument(type: indexType, ownership: .none, context)
+  let headerBuilder = Builder(atEndOf: headerBlock, location: builtinDestroyArray.location, context)
+  let cmp = headerBuilder.createBuiltinBinaryFunction(name: "cmp_slt", operandType: indexType, resultType: boolType,
+                                                      arguments: [inductionVariable, arrayCount])
+  headerBuilder.createCondBranch(condition: cmp, trueBlock: bodyBlock, falseBlock: exitBlock)
+
+  let bodyBuilder = Builder(atEndOf: bodyBlock, location: builtinDestroyArray.location, context)
+  let elementAddr = bodyBuilder.createIndexAddr(base: baseAddress, index: inductionVariable,
+                                                needStackProtection: false)
+  let destroy = bodyBuilder.createDestroyAddr(address: elementAddr)
+  let resultType = context.getTupleType(elements: [indexType, boolType]).loweredType(in: function)
+  let increment = bodyBuilder.createBuiltinBinaryFunction(name: "sadd_with_overflow", operandType: indexType,
+                                                          resultType: resultType,
+                                                          arguments: [inductionVariable, one, falseValue])
+  let incrResult = bodyBuilder.createTupleExtract(tuple: increment, elementIndex: 0)
+  bodyBuilder.createBranch(to: headerBlock, arguments: [incrResult])
+
+  context.erase(instruction: builtinDestroyArray)
+
+  return devirtualize(destroy: destroy, context)
+}
+
 private extension EnumCases {
   func allPayloadsAreTrivial(in function: Function) -> Bool {
     allSatisfy({ $0.payload?.isTrivial(in: function) ?? true })
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/DiagnosticEngine.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/DiagnosticEngine.swift
deleted file mode 100644
index 2d31c4808aa39..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/DiagnosticEngine.swift
+++ /dev/null
@@ -1,146 +0,0 @@
-//===--- DiagnosticEngine.swift -------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import ASTBridging
-
-import Basic
-import SIL
-
-typealias DiagID = BridgedDiagID
-
-protocol DiagnosticArgument {
-  func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void)
-}
-extension String: DiagnosticArgument {
-  func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
-    _withBridgedStringRef { fn(BridgedDiagnosticArgument($0)) }
-  }
-}
-extension StringRef: DiagnosticArgument {
-  func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
-    fn(BridgedDiagnosticArgument(_bridged))
-  }
-}
-extension Int: DiagnosticArgument {
-  func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
-    fn(BridgedDiagnosticArgument(self))
-  }
-}
-extension Type: DiagnosticArgument {
-  func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
-    fn(bridged.asDiagnosticArgument())
-  }
-}
-extension DeclRef: DiagnosticArgument {
-  func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
-    fn(bridged.asDiagnosticArgument())
-  }
-}
-
-struct DiagnosticFixIt {
-  let start: SourceLoc
-  let byteLength: Int
-  let text: String
-
-  init(start: SourceLoc, byteLength: Int, replacement text: String) {
-    self.start = start
-    self.byteLength = byteLength
-    self.text = text
-  }
-
-  func withBridgedDiagnosticFixIt(_ fn: (BridgedDiagnosticFixIt) -> Void) {
-    text._withBridgedStringRef { bridgedTextRef in
-      let bridgedDiagnosticFixIt = BridgedDiagnosticFixIt(
-        start.bridged, UInt32(byteLength),
-        bridgedTextRef)
-      fn(bridgedDiagnosticFixIt)
-    }
-  }
-}
-
-struct DiagnosticEngine {
-  private let bridged: BridgedDiagnosticEngine
-
-  init(bridged: BridgedDiagnosticEngine) {
-    self.bridged = bridged
-  }
-  init?(bridged: BridgedNullableDiagnosticEngine) {
-    guard let raw = bridged.raw else {
-      return nil
-    }
-    self.bridged = BridgedDiagnosticEngine(raw: raw)
-  }
-
-  func diagnose(_ position: SourceLoc?,
-                       _ id: DiagID,
-                       _ args: [DiagnosticArgument],
-                       highlight: CharSourceRange? = nil,
-                       fixIts: [DiagnosticFixIt] = []) {
-
-    let bridgedSourceLoc: BridgedSourceLoc = position.bridged
-    let highlightStart: BridgedSourceLoc
-    let highlightLength: UInt32
-    if let highlight = highlight {
-      highlightStart = highlight.start.bridged
-      highlightLength = highlight.byteLength
-    } else {
-      highlightStart = BridgedSourceLoc()
-      highlightLength = 0
-    }
-    var bridgedArgs: [BridgedDiagnosticArgument] = []
-    var bridgedFixIts: [BridgedDiagnosticFixIt] = []
-
-    // Build a higher-order function to wrap every 'withBridgedXXX { ... }'
-    // calls, so we don't escape anything from the closure. 'bridgedArgs' and
-    // 'bridgedFixIts' are temporary storage to store bridged values. So they
-    // should not be used after the closure is executed.
- 
-    var closure: () -> Void = {
-      bridgedArgs.withBridgedArrayRef { bridgedArgsRef in
-        bridgedFixIts.withBridgedArrayRef { bridgedFixItsRef in
-          bridged.diagnose(at: bridgedSourceLoc, id, bridgedArgsRef,
-                           highlightAt: highlightStart,
-                           highlightLength: highlightLength,
-                           fixIts: bridgedFixItsRef)
-        }
-      }
-    }
-    // 'reversed()' because the closure should be wrapped in that order.
-    for arg in args.reversed() {
-      closure = { [closure, arg] in
-        arg._withBridgedDiagnosticArgument { bridgedArg in
-          bridgedArgs.append(bridgedArg)
-          closure()
-        }
-      }
-    }
-    // 'reversed()' because the closure should be wrapped in that order.
-    for fixIt in fixIts.reversed() {
-      closure = { [closure, fixIt] in
-        fixIt.withBridgedDiagnosticFixIt { bridgedFixIt in
-          bridgedFixIts.append(bridgedFixIt)
-          closure()
-        }
-      }
-    }
-
-    closure()
-  }
-
-  func diagnose(_ position: SourceLoc?,
-                       _ id: DiagID,
-                       _ args: DiagnosticArgument...,
-                       highlight: CharSourceRange? = nil,
-                       fixIts: DiagnosticFixIt...) {
-    diagnose(position, id, args, highlight: highlight, fixIts: fixIts)
-  }
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/EscapeUtils.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/EscapeUtils.swift
index 125d26fca4ab9..278c26c12cd4b 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/EscapeUtils.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/EscapeUtils.swift
@@ -519,7 +519,7 @@ fileprivate struct EscapeWalker<V: EscapeVisitor> : ValueDefUseWalker,
       if operand == copyAddr.sourceOperand {
         return walkUp(address: copyAddr.destination, path: path)
       } else {
-        if !copyAddr.isInitializationOfDest {
+        if !copyAddr.isInitializationOfDestination {
           if handleDestroy(of: operand.value, path: path.with(knownType: nil)) == .abortWalk {
             return .abortWalk
           }
@@ -640,12 +640,14 @@ fileprivate struct EscapeWalker<V: EscapeVisitor> : ValueDefUseWalker,
     }
 
     // Indirect arguments cannot escape the function, but loaded values from such can.
-    if !followLoads(at: path) {
-      guard let beginApply = apply as? BeginApplyInst else {
-        return .continueWalk
-      }
-      // Except for begin_apply: it can yield an address value.
-      if !indirectResultEscapes(of: beginApply, path: path) {
+    if argOp.value.type.isAddress && !followLoads(at: path) {
+      if let beginApply = apply as? BeginApplyInst {
+        // begin_apply can yield an address value.
+        if !indirectResultEscapes(of: beginApply, path: path) {
+          return .continueWalk
+        }
+      } else if !apply.isAddressable(operand: argOp) {
+        // The result does not depend on the argument's address.
         return .continueWalk
       }
     }
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/FunctionSignatureTransforms.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/FunctionSignatureTransforms.swift
index 5b8575a198a07..310dec2c9f9c9 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/FunctionSignatureTransforms.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/FunctionSignatureTransforms.swift
@@ -12,6 +12,29 @@
 
 import SIL
 
+private extension ArgumentConventions {
+  func isLifetimeSourceOrTarget(index argIndex: Int) -> Bool {
+    // Check if `argIndex` is a lifetime target
+    if self[parameterDependencies: argIndex] != nil {
+      return true
+    }
+
+    // Check if `argIndex` is a lifetime source in resultDependencies
+    if self[resultDependsOn: argIndex] != nil {
+      return true
+    }
+
+    // Check if `argIndex` is a lifetime source in parameterDependencies
+    for targetIndex in firstParameterIndex..<self.count {
+      if getDependence(target: targetIndex, source: argIndex) != nil {
+        return true
+      }
+    }
+
+    return false
+  }
+}
+
 /// Replace an apply with metatype arguments with an apply to a specialized function, where the
 /// metatype values are not passed, but rematerialized in the entry block of the specialized function
 ///
@@ -52,6 +75,15 @@ func specializeByRemovingMetatypeArguments(apply: FullApplySite, _ context: Modu
     return
   }
 
+  // If a function has lifetime dependencies, bailout if dead arguments precede lifetime sources or targets
+  if callee.convention.hasLifetimeDependencies() {
+    for (argIndex, _) in callee.arguments.enumerated() where argIndex >= deadArgIndices.first! {
+      if callee.argumentConventions.isLifetimeSourceOrTarget(index: argIndex) {
+        return
+      }
+    }
+  }
+
   let specializedFuncName = context.mangle(withDeadArguments: deadArgIndices, from: callee)
 
   let specializedCallee: Function
@@ -88,7 +120,7 @@ private func createSpecializedFunction(
     hasSelfParameter: hasSelfParameter,
     fromOriginal: originalFunction)
 
-  let thunkLoc = originalFunction.entryBlock.instructions.first!.location.autoGenerated
+  let thunkLoc = originalFunction.entryBlock.instructions.first!.location.asAutoGenerated
 
   context.moveFunctionBody(from: originalFunction, to: specializedFunction)
   // originalFunction is now empty and used as the thunk.
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/FunctionTest.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/FunctionTest.swift
new file mode 100644
index 0000000000000..701fe2819e86d
--- /dev/null
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/FunctionTest.swift
@@ -0,0 +1,102 @@
+//===----------- FunctionTest.swift ---------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// Optimizer test infrastructure.
+//
+// For general documentation on how to write tests see `Test.swift` in the
+// SIL module.
+// To add an optimizer test, use `FunctionTest` instead of `Test` and register
+// it in `registerOptimizerTests`.
+//
+//===----------------------------------------------------------------------===//
+
+import SIL
+import OptimizerBridging
+
+/// Like `SIL.Test`,  but provides a `FunctionPass` to the invocation closure.
+struct FunctionTest {
+  let name: String
+  let invocation: FunctionTestInvocation
+
+  public init(_ name: String, invocation: @escaping FunctionTestInvocation) {
+    self.name = name
+    self.invocation = invocation
+  }
+}
+
+/// The type of the closure passed to a FunctionTest.
+typealias FunctionTestInvocation = @convention(thin) (Function, TestArguments, FunctionPassContext) -> ()
+
+public func registerOptimizerTests() {
+  SIL.registerTests()
+
+  // Register each test.
+  registerFunctionTests(
+    addressOwnershipLiveRangeTest,
+    argumentConventionsTest,
+    interiorLivenessTest,
+    lifetimeDependenceRootTest,
+    lifetimeDependenceScopeTest,
+    lifetimeDependenceUseTest,
+    linearLivenessTest,
+    localVariableReachableUsesTest,
+    localVariableReachingAssignmentsTest,
+    rangeOverlapsPathTest,
+    variableIntroducerTest
+  )
+
+  // Finally register the thunk they all call through.
+  registerFunctionTestThunk(functionTestThunk)
+}
+
+private func registerFunctionTests(_ tests: FunctionTest...) {
+  tests.forEach { registerFunctionTest($0) }
+}
+
+private func registerFunctionTest(_ test: FunctionTest) {
+  test.name._withBridgedStringRef { ref in
+    registerFunctionTest(ref, castToOpaquePointer(fromInvocation: test.invocation))
+  }
+}
+
+/// The function called by the swift::test::FunctionTest which invokes the
+/// actual test function.
+///
+/// This function is necessary because tests need to be written in terms of
+/// native Swift types (Function, TestArguments, FunctionPassContext)
+/// rather than their bridged variants, but such a function isn't representable
+/// in C++. This thunk unwraps the bridged types and invokes the real function.
+private func functionTestThunk(
+  _ erasedInvocation: UnsafeMutableRawPointer,
+  _ function: BridgedFunction, 
+  _ arguments: BridgedTestArguments, 
+  _ bridgedContext: BridgedContext) {
+  let invocation = castToInvocation(fromOpaquePointer: erasedInvocation)
+  let context = FunctionPassContext(_bridged: bridgedContext)
+  invocation(function.function, arguments.native, context)
+}
+
+/// Bitcast a thin test closure to void *.
+///
+/// Needed so that the closure can be represented in C++ for storage in the test
+/// registry.
+private func castToOpaquePointer(fromInvocation invocation: FunctionTestInvocation) -> UnsafeMutableRawPointer {
+  return unsafeBitCast(invocation, to: UnsafeMutableRawPointer.self)
+}
+
+/// Bitcast a void * to a thin test closure.
+///
+/// Needed so that the closure stored in the C++ test registry can be invoked
+/// via the functionTestThunk.
+private func castToInvocation(fromOpaquePointer erasedInvocation: UnsafeMutableRawPointer) -> FunctionTestInvocation {
+  return unsafeBitCast(erasedInvocation, to: FunctionTestInvocation.self)
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/GenericSpecialization.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/GenericSpecialization.swift
index e5f8dae6214a8..ef8dbc679afc8 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/GenericSpecialization.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/GenericSpecialization.swift
@@ -50,7 +50,7 @@ private struct VTableSpecializer {
     let classDecl = classType.nominal! as! ClassDecl
     guard let origVTable = context.lookupVTable(for: classDecl) else {
       if context.enableWMORequiredDiagnostics {
-        context.diagnosticEngine.diagnose(errorLocation.sourceLoc, .cannot_specialize_class, classType)
+        context.diagnosticEngine.diagnose(.cannot_specialize_class, classType, at: errorLocation)
       }
       return
     }
@@ -79,7 +79,7 @@ private struct VTableSpecializer {
   }
 
   private func specializeEntries(of vTable: VTable, _ notifyNewFunction: (Function) -> ()) -> [VTable.Entry] {
-    return vTable.entries.compactMap { entry in
+    return vTable.entries.map { entry in
       if !entry.implementation.isGeneric {
         return entry
       }
@@ -89,10 +89,10 @@ private struct VTableSpecializer {
 
       guard !methodSubs.conformances.contains(where: {!$0.isValid}),
             context.loadFunction(function: entry.implementation, loadCalleesRecursively: true),
-            let specializedMethod = context.specialize(function: entry.implementation, for: methodSubs) else
-      {
-        context.diagnosticEngine.diagnose(entry.methodDecl.location.sourceLoc, .non_final_generic_class_function)
-        return nil
+            let specializedMethod = context.specialize(function: entry.implementation, for: methodSubs,
+                                                       convertIndirectToDirect: true, isMandatory: true)
+      else {
+        return entry
       }
       notifyNewFunction(specializedMethod)
 
@@ -106,16 +106,32 @@ private struct VTableSpecializer {
   }
 }
 
-func specializeWitnessTable(forConformance conformance: Conformance,
-                            errorLocation: Location,
-                            _ context: ModulePassContext,
-                            _ notifyNewWitnessTable: (WitnessTable) -> ())
-{
-  let genericConformance = conformance.genericConformance
-  guard let witnessTable = context.lookupWitnessTable(for: genericConformance) else {
+/// Specializes a witness table of `conformance` for the concrete type of the conformance.
+func specializeWitnessTable(for conformance: Conformance, _ context: ModulePassContext) {
+  if let existingSpecialization = context.lookupWitnessTable(for: conformance),
+         existingSpecialization.isSpecialized
+  {
+    return
+  }
+
+  guard conformance.isConcrete else {
+    // If the conformance is abstract the witness table is specialized elsewhere - at the
+    // place where the concrete conformance is referenced.
+    return
+  }
+
+  let baseConf = conformance.isInherited ? conformance.inheritedConformance: conformance
+  if !baseConf.isSpecialized {
+    var visited = Set<Conformance>()
+    specializeDefaultMethods(for: conformance, visited: &visited, context)
+    return
+  }
+
+  guard let witnessTable = context.lookupWitnessTable(for: baseConf.genericConformance) else {
     fatalError("no witness table found")
   }
   assert(witnessTable.isDefinition, "No witness table available")
+  let substitutions = baseConf.specializedSubstitutions
 
   let newEntries = witnessTable.entries.map { origEntry in
     switch origEntry {
@@ -125,13 +141,15 @@ func specializeWitnessTable(forConformance conformance: Conformance,
       guard let origMethod = witness else {
         return origEntry
       }
-      let methodSubs = conformance.specializedSubstitutions.getMethodSubstitutions(for: origMethod)
+      let methodSubs = substitutions.getMethodSubstitutions(for: origMethod,
+                         // Generic self types need to be handled specially (see `getMethodSubstitutions`)
+                         selfType: origMethod.hasGenericSelf(context) ? conformance.type.canonical : nil)
 
       guard !methodSubs.conformances.contains(where: {!$0.isValid}),
             context.loadFunction(function: origMethod, loadCalleesRecursively: true),
-            let specializedMethod = context.specialize(function: origMethod, for: methodSubs) else
-      {
-        context.diagnosticEngine.diagnose(errorLocation.sourceLoc, .cannot_specialize_witness_method, requirement)
+            let specializedMethod = context.specialize(function: origMethod, for: methodSubs,
+                                                       convertIndirectToDirect: true, isMandatory: true)
+      else {
         return origEntry
       }
       return .method(requirement: requirement, witness: specializedMethod)
@@ -139,25 +157,113 @@ func specializeWitnessTable(forConformance conformance: Conformance,
       let baseConf = context.getSpecializedConformance(of: witness,
                                                        for: conformance.type,
                                                        substitutions: conformance.specializedSubstitutions)
-      specializeWitnessTable(forConformance: baseConf, errorLocation: errorLocation, context, notifyNewWitnessTable)
+      specializeWitnessTable(for: baseConf, context)
       return .baseProtocol(requirement: requirement, witness: baseConf)
     case .associatedType(let requirement, let witness):
       let substType = witness.subst(with: conformance.specializedSubstitutions)
       return .associatedType(requirement: requirement, witness: substType)
-    case .associatedConformance(let requirement, let substType, let assocConf):
-      // FIXME: let concreteAssociateConf = assocConf.subst(with: conformance.specializedSubstitutions)
-      let concreteAssociateConf = conformance.getAssociatedConformance(ofAssociatedType: requirement.rawType, to: assocConf.proto)
+    case .associatedConformance(let requirement, let assocConf):
+      // TODO: once we have the API, replace this with:
+      //       let concreteAssociateConf = assocConf.subst(with: conformance.specializedSubstitutions)
+      let concreteAssociateConf = conformance.getAssociatedConformance(ofAssociatedType: requirement.rawType,
+                                                                       to: assocConf.protocol)
       if concreteAssociateConf.isSpecialized {
-        specializeWitnessTable(forConformance: concreteAssociateConf,
-                               errorLocation: errorLocation,
-                               context, notifyNewWitnessTable)
+        specializeWitnessTable(for: concreteAssociateConf, context)
       }
       return .associatedConformance(requirement: requirement,
-                                    substType: substType.subst(with: conformance.specializedSubstitutions),
                                     witness: concreteAssociateConf)
     }
   }
-  let newWT = context.createWitnessTable(entries: newEntries,conformance: conformance,
-                                         linkage: .shared, serialized: false)
-  notifyNewWitnessTable(newWT)
+  context.createSpecializedWitnessTable(entries: newEntries,conformance: conformance,
+                                        linkage: .shared, serialized: false)
+}
+
+/// Specializes the default methods of a non-generic witness table.
+/// Default implementations (in protocol extensions) of non-generic protocol methods have a generic
+/// self argument. Specialize such methods with the concrete type. Note that it is important to also
+/// specialize inherited conformances so that the concrete self type is correct, even for derived classes.
+private func specializeDefaultMethods(for conformance: Conformance,
+                                      visited: inout Set<Conformance>,
+                                      _ context: ModulePassContext)
+{
+  // Avoid infinite recursion, which may happen if an associated conformance is the conformance itself.
+  guard visited.insert(conformance).inserted,
+        let witnessTable = context.lookupWitnessTable(for: conformance.rootConformance)
+  else {
+    return
+  }
+
+  assert(witnessTable.isDefinition, "No witness table available")
+
+  var specialized = false
+
+  let newEntries = witnessTable.entries.map { origEntry in
+    switch origEntry {
+    case .invalid:
+      return WitnessTable.Entry.invalid
+    case .method(let requirement, let witness):
+      guard let origMethod = witness,
+            // Is it a generic method where only self is generic (= a default witness method)?
+            origMethod.isGeneric, origMethod.isNonGenericWitnessMethod(context)
+      else {
+        return origEntry
+      }
+      // Replace the generic self type with the concrete type.
+      let methodSubs = SubstitutionMap(genericSignature: origMethod.genericSignature,
+                                       replacementTypes: [conformance.type])
+
+      guard !methodSubs.conformances.contains(where: {!$0.isValid}),
+            context.loadFunction(function: origMethod, loadCalleesRecursively: true),
+            let specializedMethod = context.specialize(function: origMethod, for: methodSubs,
+                                                       convertIndirectToDirect: true, isMandatory: true)
+      else {
+        return origEntry
+      }
+      specialized = true
+      return .method(requirement: requirement, witness: specializedMethod)
+    case .baseProtocol(_, let witness):
+      specializeDefaultMethods(for: witness, visited: &visited, context)
+      return origEntry
+    case .associatedType:
+      return origEntry
+    case .associatedConformance(_, let assocConf):
+      specializeDefaultMethods(for: assocConf, visited: &visited, context)
+      return origEntry
+    }
+  }
+  // If the witness table does not contain any default methods, there is no need to create a
+  // specialized witness table.
+  if specialized {
+    context.createSpecializedWitnessTable(entries: newEntries,conformance: conformance,
+                                          linkage: .shared, serialized: false)
+  }
+}
+
+private extension Function {
+  // True, if this is a non-generic method which might have a generic self argument.
+  // Default implementations (in protocol extensions) of non-generic protocol methods have a generic
+  // self argument.
+  func isNonGenericWitnessMethod(_ context: some Context) -> Bool {
+    switch loweredFunctionType.invocationGenericSignatureOfFunction.genericParameters.count {
+    case 0:
+      return true
+    case 1:
+      return hasGenericSelf(context)
+    default:
+      return false
+    }
+  }
+
+  // True, if the self argument is a generic parameter.
+  func hasGenericSelf(_ context: some Context) -> Bool {
+    let convention = FunctionConvention(for: loweredFunctionType,
+                                        hasLoweredAddresses: context.moduleHasLoweredAddresses)
+    if convention.hasSelfParameter,
+       let selfParam = convention.parameters.last,
+       selfParam.type.isGenericTypeParameter
+    {
+      return true
+    }
+    return false
+  }
 }
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/LifetimeDependenceUtils.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/LifetimeDependenceUtils.swift
index d992481da692b..21de12feaf86d 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/LifetimeDependenceUtils.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/LifetimeDependenceUtils.swift
@@ -161,20 +161,16 @@ extension LifetimeDependence {
 
   // Construct a LifetimeDependence from a return value. This only
   // constructs a dependence for ~Escapable results that do not have a
-  // lifetime dependence (@_unsafeNonescapableResult).
+  // lifetime dependence (@lifetime(immortal), @_unsafeNonescapableResult).
   //
   // This is necessary because inserting a mark_dependence placeholder for such an unsafe dependence would illegally
   // have the same base and value operand.
-  //
-  // TODO: handle indirect results
-  init?(unsafeApplyResult value: Value, _ context: some Context) {
+  init?(unsafeApplyResult value: Value, apply: FullApplySite, _ context: some Context) {
     if value.isEscapable {
       return nil
     }
-    if (value.definingInstructionOrTerminator as! FullApplySite).hasResultDependence {
-      return nil
-    }
-    assert(value.ownership == .owned, "unsafe apply result must be owned")
+    assert(!apply.hasResultDependence, "mark_dependence should be used instead")
+    assert(value.ownership == .owned || value.type.isAddress, "unsafe apply result must be owned")
     self.scope = Scope(base: value, context)
     self.dependentValue = value
     self.markDepInst = nil
@@ -226,9 +222,9 @@ extension LifetimeDependence {
     return scope.computeRange(context)
   }
 
-  func resolve(_ context: some Context) {
+  func resolve(_ context: some MutatingContext) {
     if let mdi = markDepInst {
-      mdi.resolveToNonEscaping()
+      mdi.resolveToNonEscaping(context)
     }
   }
 }
@@ -279,8 +275,18 @@ extension LifetimeDependence.Scope {
     case let .box(projectBox):
       // Note: the box may be in a borrow scope.
       self.init(base: projectBox.operand.value, context)
-    case .stack, .class, .tail, .pointer, .index, .unidentified:
+    case .class, .tail, .pointer, .index:
       self = .unknown(accessBase.address!)
+    case .unidentified:
+      self = .unknown(address)
+    case let .stack(allocStack):
+      if let initializer = accessBase.findSingleInitializer(context) {
+        if case let .store(store, _) = initializer {
+          self = .initialized(.store(initializingStore: store, initialAddress: allocStack))
+          return
+        }
+      }
+      self = .unknown(allocStack)
     case .global:
       // TODO: When AccessBase directly stores GlobalAccessBase, we don't need a check here and don't need to pass
       // 'address' in to this function.
@@ -375,8 +381,30 @@ extension LifetimeDependence.Scope {
   }
 }
 
+// Scope helpers.
 extension LifetimeDependence.Scope {
-  /// Ignore "irrelevent" borrow scopes: load_borrow or begin_borrow without [var_decl]
+  // If the LifetimeDependenceScope is .initialized, then return the alloc_stack.
+  var allocStackInstruction: AllocStackInst? {
+    switch self {
+    case let .initialized(initializer):
+      switch initializer {
+      case let .store(initializingStore: store, initialAddress):
+        if let allocStackInst = initialAddress as? AllocStackInst {
+          return allocStackInst
+        }
+        if let sb = store as? StoreBorrowInst {
+          return sb.allocStack
+        }
+        return nil
+      default:
+        return nil
+      }
+      default:
+        return nil
+    }
+  }
+
+  /// Ignore "irrelevant" borrow scopes: load_borrow or begin_borrow without [var_decl]
   func ignoreBorrowScope(_ context: some Context) -> LifetimeDependence.Scope? {
     guard case let .borrowed(beginBorrowVal) = self else {
       return nil
@@ -400,6 +428,21 @@ extension LifetimeDependence.Scope {
   ///
   /// Returns nil if the dependence scope covers the entire function. Returns an empty range for an unknown scope.
   ///
+  /// When this Scope is live on unreachable paths, the returned range may include blocks that are not dominated by the
+  /// scope introducer. Even though 'range.isValid == false' for such a range, it is still valid for checking that
+  /// dependencies are in scope since we already know that the Scope introducer dominates all dependent uses.
+  ///
+  /// Ignore the lifetime of temporary trivial values (with .initialized and .unknown scopes). Temporaries have an
+  /// unknown Scope, which means that LifetimeDependence.Scope did not recognize a VariableScopeInstruction. This is
+  /// important to promote mark_dependence instructions emitted by SILGen to [nonescaping] (e.g. unsafeAddressor). It
+  /// also allows trivial value to be "extended" without actually tracking their scope, which is expected behavior. For
+  /// example:
+  ///
+  ///     let span = Span(buffer.baseAddress)
+  ///
+  /// If 'baseAddress' is an opaque getter, then the temporary pointer is effectively valid
+  /// until the end of the function.
+  ///
   /// Note: The caller must deinitialize the returned range.
   func computeRange(_ context: Context) -> InstructionRange? {
     switch self {
@@ -437,18 +480,13 @@ extension LifetimeDependence.Scope {
       if case let .argument(arg) = initializer, arg.convention.isInout {
         return nil
       }
+      let address = initializer.initialAddress
+      if address.type.objectType.isTrivial(in: address.parentFunction) {
+        return LifetimeDependence.Scope.computeAddressableRange(initializer: initializer, context)
+      }
       return LifetimeDependence.Scope.computeInitializedRange(initializer: initializer, context)
     case let .unknown(value):
-      // Ignore the lifetime of temporary trivial values. Temporaries have an unknown Scope, which means that
-      // LifetimeDependence.Scope did not recognize a VariableScopeInstruction. This is important to promote
-      // mark_dependence instructions emitted by SILGen to [nonescaping] (e.g. unsafeAddressor). It also allows trivial
-      // value to be "extended" without actually tracking their scope, which is expected behavior. For example:
-      //
-      //     let span = Span(buffer.baseAddress)
-      //
-      // If 'baseAddress' is an opaque getter, then the temporary pointer is effectively valid
-      // until the end of the function.
-      if value.type.isTrivial(in: value.parentFunction) {
+      if value.type.objectType.isTrivial(in: value.parentFunction) {
         return nil
       }
       // Return an empty range.
@@ -479,7 +517,7 @@ extension LifetimeDependence.Scope {
       case is DestroyAddrInst:
         range.insert(inst)
       case let sdai as SourceDestAddrInstruction
-             where sdai.sourceOperand == use && sdai.isTakeOfSrc:
+             where sdai.sourceOperand == use && sdai.isTakeOfSource:
         range.insert(inst)
       case let li as LoadInst where li.loadOwnership == .take:
         range.insert(inst)
@@ -491,6 +529,68 @@ extension LifetimeDependence.Scope {
     }
     return range
   }
+
+  // For trivial values, compute the range in which the value may have its address taken.
+  // Returns nil unless the address has both an addressable parameter use and a dealloc_stack use.
+  //
+  // This extended range is convervative. In theory, it can lead to a "false positive" diagnostic if this scope was
+  // computed for a apply site that takes this address as *non-addressable*, as opposed to the apply site discovered
+  // here that takes the alloc_stack as an *addressable* argument. This won't normally happen because addressability
+  // depends on the value's type (via @_addressableForDepenencies), so all other lifetime-dependent applies should be
+  // addressable. Furthermore, SILGen only creates temporary stack locations for addressable arguments for a single
+  // argument.
+  private static func computeAddressableRange(initializer: AccessBase.Initializer, _ context: Context)
+    -> InstructionRange? {
+    switch initializer {
+    case .argument, .yield:
+      return nil
+    case let .store(initializingStore, initialAddr):
+      guard initialAddr is AllocStackInst else {
+        return nil
+      }
+      var isAddressable = false
+      var deallocInsts = SingleInlineArray<DeallocStackInst>()
+      for use in initialAddr.uses {
+        let inst = use.instruction
+        switch inst {
+        case let apply as ApplySite:
+          isAddressable = isAddressable || apply.isAddressable(operand: use)
+        case let dealloc as DeallocStackInst:
+          deallocInsts.append(dealloc)
+        default:
+          break
+        }
+      }
+      guard isAddressable, !deallocInsts.isEmpty else {
+        // Valid on all paths to function exit.
+        return nil
+      }
+      var range = InstructionRange(begin: initializingStore, context)
+      range.insert(contentsOf: deallocInsts)
+
+      // Insert unreachable paths with no dealloc_stack.
+      var forwardUnreachableWalk = BasicBlockWorklist(context)
+      defer { forwardUnreachableWalk.deinitialize() }
+
+      // TODO: ensure complete dealloc_stack on all paths in SIL verification, then assert exitBlock.isEmpty.
+      for exitBlock in range.exitBlocks {
+        forwardUnreachableWalk.pushIfNotVisited(exitBlock)
+      }
+      while let b = forwardUnreachableWalk.pop() {
+        if let unreachableInst = b.terminator as? UnreachableInst {
+          // Note: 'unreachableInst' is not necessarilly dominated by 'initializingStore'. This marks the range invalid,
+          // but leaves it in a usable state that includes all blocks covered by the temporary allocation. The extra
+          // blocks (backward up to the function entry) are irrelevant becase we already know that 'initializingStore'
+          // dominates dependent uses.
+          range.insert(unreachableInst)
+        }
+        for succBlock in b.successors {
+          forwardUnreachableWalk.pushIfNotVisited(succBlock)
+        }
+      }
+      return range
+    }
+  }
 }
 
 // =============================================================================
@@ -548,7 +648,7 @@ protocol LifetimeDependenceDefUseWalker : ForwardingDefUseWalker,
 }
 
 extension LifetimeDependenceDefUseWalker {
-  // Use a distict context name to avoid rdar://123424566 (Unable to open existential)
+  // Use a distinct context name to avoid rdar://123424566 (Unable to open existential)
   var walkerContext: Context { context }
 }
 
@@ -562,8 +662,8 @@ extension LifetimeDependenceDefUseWalker {
     }
     let root = dependence.dependentValue
     if root.type.isAddress { 
-      // The root address may be an escapable mark_dependence that guards its address uses (unsafeAddress), or an
-      // allocation or incoming argument. In all these cases, it is sufficient to walk down the address uses.
+      // The root address may be an escapable mark_dependence that guards its address uses (unsafeAddress), an
+      // allocation, an incoming argument, or an outgoing argument. In all these cases, walk down the address uses.
       return walkDownAddressUses(of: root)
     }
     return walkDownUses(of: root, using: nil)
@@ -585,7 +685,7 @@ extension LifetimeDependenceDefUseWalker {
   // Override ForwardingDefUseWalker.
   mutating func walkDown(operand: Operand) -> WalkResult {
     // Initially delegate all uses to OwnershipUseVisitor.
-    // walkDownDefault will be called for uses that forward ownership.
+    // forwardingUse() will be called for uses that forward ownership, which then delegates to walkDownDefault().
     return classify(operand: operand)
   }
 
@@ -638,7 +738,7 @@ extension LifetimeDependenceDefUseWalker {
          is DestroyNotEscapedClosureInst, is ClassMethodInst, is SuperMethodInst,
          is ClassifyBridgeObjectInst, is DebugValueInst,
          is ObjCMethodInst, is ObjCSuperMethodInst, is UnmanagedRetainValueInst,
-         is UnmanagedReleaseValueInst, is SelectEnumInst:
+         is UnmanagedReleaseValueInst, is SelectEnumInst, is IgnoredUseInst:
       // Catch .instantaneousUse operations that are dependence leaf uses.
       return leafUse(of: operand)
 
@@ -663,6 +763,11 @@ extension LifetimeDependenceDefUseWalker {
 
   mutating func forwardingUse(of operand: Operand, isInnerLifetime: Bool)
     -> WalkResult {
+    // Lifetime dependence is only interested in dominated uses. Treat a returned phi like a dominated use by stopping
+    // at the phi operand rather than following the forwarded value to the ReturnInst.
+    if let phi = Phi(using: operand), phi.isReturnValue {
+      return returnedDependence(result: operand)
+    }
     // Delegate ownership forwarding operations to the ForwardingDefUseWalker.
     return walkDownDefault(forwarding: operand)
   }
@@ -796,7 +901,10 @@ extension LifetimeDependenceDefUseWalker {
   }
 
   private mutating func walkDownAddressUses(of address: Value) -> WalkResult {
-    address.uses.ignoreTypeDependence.walk {
+    if !needWalk(for: address) {
+      return .continueWalk
+    }
+    return address.uses.ignoreTypeDependence.walk {
       return classifyAddress(operand: $0)
     }
   }
@@ -804,7 +912,7 @@ extension LifetimeDependenceDefUseWalker {
 
 // Helpers
 extension LifetimeDependenceDefUseWalker {
-  // Visit uses of borrowing instruction (operandOwnerhip == .borrow).
+  // Visit uses of borrowing instruction (operandOwnership == .borrow).
   private mutating func visitAllBorrowUses(
     of operand: Operand, by borrowInst: BorrowingInstruction) -> WalkResult {
     switch borrowInst {
@@ -814,9 +922,15 @@ extension LifetimeDependenceDefUseWalker {
       return walkDownUses(of: bfi, using: operand)
     case let .storeBorrow(sbi):
       return walkDownAddressUses(of: sbi)
-    case .beginApply:
-      // Skip the borrow scope; the type system enforces non-escapable
-      // arguments.
+    case let .beginApply(bai):
+      // First, visit the uses of any non-Escapable yields. The yielded value may be copied and used outside the
+      // coroutine scope.  Now, visit the uses of the begin_apply token. This adds the coroutine scope itself to the
+      for yield in bai.yieldedValues {
+        if walkDownUses(of: yield, using: operand) == .abortWalk {
+          return .abortWalk
+        }
+      }
+      // lifetime to account for the scope of any arguments.
       return visitInnerBorrowUses(of: borrowInst, operand: operand)
     case .partialApply, .markDependence:
       fatalError("OwnershipUseVisitor should bypass partial_apply [on_stack] "
@@ -829,7 +943,7 @@ extension LifetimeDependenceDefUseWalker {
     }
   }
 
-  // Visit a dependent local variable (alloc_box), or temporary storage (alloc_stack). The depenedency is typically from
+  // Visit a dependent local variable (alloc_box), or temporary storage (alloc_stack). The dependency is typically from
   // storing a dependent value at `address`, but may be from an outright `mark_dependence_addr`.
   //
   // This handles stores of the entire value and stores into a member. Storing into a member makes the entire aggregate
@@ -910,6 +1024,10 @@ extension LifetimeDependenceDefUseWalker {
         return loadedAddressUse(of: localAccess.operand!, intoValue: load)
       case let copyAddr as SourceDestAddrInstruction:
         return loadedAddressUse(of: localAccess.operand!, intoAddress: copyAddr.destinationOperand)
+      case is SwitchEnumAddrInst:
+        // switch_enum_addr does not produce any values. Subsequent uses of the address (unchecked_enum_data_addr)
+        // directly use the original address.
+        return .continueWalk
       default:
         return .abortWalk
       }
@@ -929,9 +1047,9 @@ extension LifetimeDependenceDefUseWalker {
       // Simply a marker that indicates the start of an in-memory dependent value. If this was a mark_dependence, uses
       // of its forwarded address has were visited by LocalVariableAccessWalker and recorded as separate local accesses.
       return .continueWalk
-    case .store:
-      let si = localAccess.operand!.instruction as! StoringInstruction
-      assert(si.sourceOperand == initialValue, "the only reachable store should be the current assignment")
+    case .store, .storeBorrow:
+      // A store does not use the previous in-memory value.
+      return .continueWalk
     case .apply:
       return visitAppliedUse(of: localAccess.operand!, by: localAccess.instruction as! FullApplySite)
     case .escape:
@@ -945,13 +1063,15 @@ extension LifetimeDependenceDefUseWalker {
       return yieldedDependence(result: localAccess.operand!)
     case .incomingArgument:
       fatalError("Incoming arguments are never reachable")
+    case .deadEnd:
+      return .continueWalk
     }
-    return .continueWalk
   }
 
   private mutating func visitAppliedUse(of operand: Operand, by apply: FullApplySite) -> WalkResult {
     if let conv = apply.convention(of: operand), conv.isIndirectOut {
-      return leafUse(of: operand)
+      // This apply initializes an allocation.
+      return dependentUse(of: operand, dependentAddress: operand.value)
     }
     if apply.isCallee(operand: operand) {
       return leafUse(of: operand)
@@ -1065,6 +1185,277 @@ private struct LifetimeDependenceUsePrinter : LifetimeDependenceDefUseWalker {
   }
 }
 
+// =============================================================================
+// LifetimeDependenceUseDefWalker - upward walk
+// =============================================================================
+
+/// Walk up lifetime dependencies to the first value associated with a variable declaration.
+///
+/// To start walking:
+///     walkUp(newLifetime: Value) -> WalkResult
+///
+/// This utility finds a value or address that is the best-effort "root" of the chain of temporary lifetime-dependent
+/// values.
+///
+/// This "looks through" projections: a property that is either visible as a stored property or access via
+/// unsafe[Mutable]Address.
+///
+///     dependsOn(lvalue.field) // finds 'lvalue' when 'field' is a stored property
+///
+///     dependsOn(lvalue.computed) // finds the temporary value directly returned by a getter.
+///
+/// SILGen emits temporary copies that violate lifetime dependence semantics. This utility looks through such temporary
+/// copies, stopping at a value that introduces an immutable variable: move_value [var_decl] or begin_borrow [var_decl],
+/// or at an access of a mutable variable: begin_access [read] or begin_access [modify].
+///
+/// In this example, the dependence "root" is copied, borrowed, and forwarded before being used as the base operand of
+/// `mark_dependence`. The dependence "root" is the parent of the outer-most dependence scope.
+///
+///     %root = apply                  // lifetime dependence root
+///     %copy = copy_value %root
+///     %parent = begin_borrow %copy   // lifetime dependence parent value
+///     %base = struct_extract %parent // lifetime dependence base value
+///     %dependent = mark_dependence [nonescaping] %value on %base
+///
+/// LifetimeDependenceUseDefWalker extends the ForwardingUseDefWalker to follow copies, moves, and
+/// borrows. ForwardingUseDefWalker treats these as forward-extended lifetime introducers. But they inherit a lifetime
+/// dependency from their operand because non-escapable values can be copied, moved, and borrowed. Nonetheless, all of
+/// their uses must remain within original dependence scope.
+///
+///   # owned lifetime dependence
+///   %parent = apply               // begin dependence scope -+
+///   ...                                                      |
+///   %1 = mark_dependence [nonescaping] %value on %parent     |
+///   ...                                                      |
+///   %2 = copy_value %1        -+                             |
+///   # forwarding instruction   |                             |
+///   %3 = struct $S (%2)        | forward-extended lifetime   |
+///                              |                             | OSSA Lifetime
+///   %4 = move_value %3        -+                             |
+///   ...                        | forward-extended lifetime   |
+///   %5 = begin_borrow %4       | -+                          |
+///   # dependent use of %1      |  | forward-extended lifetime|
+///   end_borrow %5              | -+                          |
+///   destroy_value %4          -+                             |
+///   ...                                                      |
+///   destroy_value %parent        // end dependence scope    -+
+///
+/// All of the dependent uses including `end_borrow %5` and `destroy_value %4` must be before the end of the dependence
+/// scope: `destroy_value %parent`. In this case, the dependence parent is an owned value, so the scope is simply the
+/// value's OSSA lifetime.
+///
+/// The ForwardingUseDefWalker's PathContext is the most recent lifetime owner (Value?). If we ever want to track the
+/// access path as well, then we can aggregate both the owner and access path in a single PathContext.
+protocol LifetimeDependenceUseDefValueWalker : ForwardingUseDefWalker where PathContext == Value? {
+  var context: Context { get }
+
+  // 'path' is the lifetime "owner": the "def" into which the current 'value' is eventually forwarded.
+  mutating func introducer(_ value: Value, _ path: PathContext) -> WalkResult
+
+  // Minimally, check a ValueSet. This walker may traverse chains of
+  // aggregation and destructuring along with phis.
+  //
+  // 'path' is the "owner" of the forwarded value.
+  mutating func needWalk(for value: Value, _ path: PathContext) -> Bool
+
+  // The 'newLifetime' value is not forwarded to its uses.
+  mutating func walkUp(newLifetime: Value) -> WalkResult
+
+  // 'owner' is the "def" into which the current 'value' is eventually forwarded.
+  mutating func walkUp(value: Value, _ owner: Value?) -> WalkResult
+}
+
+// Defaults
+extension LifetimeDependenceUseDefValueWalker {
+  mutating func walkUp(value: Value, _ owner: Value?) -> WalkResult {
+    walkUpDefault(value: value, owner)
+  }
+}
+
+// Helpers
+extension LifetimeDependenceUseDefValueWalker {
+  mutating func walkUpDefault(value: Value, _ owner: Value?) -> WalkResult {
+    switch value.definingInstruction {
+    case let transition as OwnershipTransitionInstruction:
+      return walkUp(newLifetime: transition.operand.value)
+    case let load as LoadInstruction:
+      return walkUp(newLifetime: load.address)
+    default:
+      break
+    }
+    // If the dependence chain has a phi, consider it a root. Dependence roots dominate all dependent values.
+    if Phi(value) != nil {
+      return introducer(value, owner)
+    }
+    // ForwardingUseDefWalker will callback to introducer() when it finds no forwarding instruction.
+    return walkUpDefault(forwarded: value, owner)
+  }
+}
+
+protocol LifetimeDependenceUseDefAddressWalker {
+  var context: Context { get }
+
+  // If the scoped value is trivial, then only the variable's lexical scope is relevant, and access scopes can be
+  // ignored.
+  var isTrivialScope: Bool { get }
+
+  mutating func needWalk(for address: Value) -> Bool
+
+  mutating func addressIntroducer(_ address: Value, access: AccessBaseAndScopes) -> WalkResult
+
+  // The 'newLifetime' value is not forwarded to its uses. It may be a non-address or an address.
+  mutating func walkUp(newLifetime: Value) -> WalkResult
+
+  mutating func walkUp(address: Value, access: AccessBaseAndScopes) -> WalkResult
+}
+
+// Defaults
+extension LifetimeDependenceUseDefAddressWalker {
+  mutating func walkUp(address: Value, access: AccessBaseAndScopes) -> WalkResult {
+    walkUpDefault(address: address, access: access)
+  }
+}
+
+// Helpers
+extension LifetimeDependenceUseDefAddressWalker {
+  mutating func walkUp(address: Value) -> WalkResult {
+    walkUp(address: address, access: address.accessBaseWithScopes)
+  }
+
+  mutating func walkUpDefault(address: Value, access: AccessBaseAndScopes) -> WalkResult {
+    if !needWalk(for: address) {
+      return .continueWalk
+    }
+    if let beginAccess = access.innermostAccess {
+      // Skip the access scope for unsafe[Mutable]Address. Treat it like a projection of 'self' rather than a separate
+      // variable access.
+      if let addressorSelf = beginAccess.unsafeAddressorSelf {
+        return walkUp(newLifetime: addressorSelf)
+      }
+      // Ignore the access scope for trivial values regardless of whether it is singly-initialized. Trivial values do not
+      // need to be kept alive in memory and can be safely be overwritten in the same scope. Lifetime dependence only
+      // cares that the loaded value is within the lexical scope of the trivial value's variable declaration. Rather
+      // than skipping all access scopes, call 'walkUp' on each nested access in case one of them needs to redirect the
+      // walk, as required for 'access.unsafeAddressorSelf' or in case the implementation overrides certain accesses.
+      if isTrivialScope {
+        return walkUp(newLifetime: beginAccess.address)
+      }
+      // Generally assume an access scope introduces a variable borrow scope. And generally ignore address forwarding
+      // mark_dependence.
+      return addressIntroducer(beginAccess, access: access)
+    }
+    // Continue walking for some kinds of access base.
+    switch access.base {
+    case .box, .global, .class, .tail, .pointer, .index, .unidentified:
+      break
+    case let .stack(allocStack):
+      // Ignore stack locations. Their access scopes do not affect lifetime dependence.
+      return walkUp(stackInitializer: allocStack, at: address, access: access)
+    case let .argument(arg):
+      if arg.convention.isExclusiveIndirect {
+        return addressIntroducer(arg, access: access)
+      }
+    case let .yield(yieldedAddress):
+      // Ignore access scopes for @in or @in_guaranteed yields when all scopes are reads.
+      let apply = yieldedAddress.definingInstruction as! FullApplySite
+      if apply.convention(of: yieldedAddress).isIndirectIn && access.isOnlyReadAccess {
+        return addressIntroducer(yieldedAddress, access: access)
+      }
+    case .storeBorrow(let sb):
+      // Walk up through a store into a temporary.
+      if access.scopes.isEmpty,
+         case .stack = sb.destinationOperand.value.accessBase {
+        return walkUp(newLifetime: sb.source)
+      }
+    }
+    return addressIntroducer(access.enclosingAccess.address ?? address, access: access)
+  }
+
+  // Handle singly-initialized temporary stack locations.
+  mutating func walkUp(stackInitializer allocStack: AllocStackInst, at address: Value,
+                       access: AccessBaseAndScopes) -> WalkResult {
+    guard let initializer = allocStack.accessBase.findSingleInitializer(context) else {
+      return addressIntroducer(address, access: access)
+    }
+    if case let .store(store, _) = initializer {
+      switch store {
+      case let store as StoringInstruction:
+        return walkUp(newLifetime: store.source)
+      case let srcDestInst as SourceDestAddrInstruction:
+        return walkUp(newLifetime: srcDestInst.source)
+      case let apply as FullApplySite:
+        if let f = apply.referencedFunction, f.isConvertPointerToPointerArgument {
+          return walkUp(newLifetime: apply.parameterOperands[0].value)
+        }
+      default:
+        break
+      }
+    }
+    return addressIntroducer(address, access: access)
+  }
+}
+
+/// Walk up through all new lifetimes to find the roots of a lifetime dependence chain.
+struct LifetimeDependenceRootWalker : LifetimeDependenceUseDefValueWalker, LifetimeDependenceUseDefAddressWalker {
+  // The ForwardingUseDefWalker's context is the most recent lifetime owner.
+  typealias PathContext = Value?
+
+  let context: Context
+
+  // If the scoped value is trivial, then only the variable's lexical scope is relevant, and access scopes can be
+  // ignored.
+  let isTrivialScope: Bool
+
+  // This visited set is only really needed for instructions with
+  // multiple results, including phis.
+  private var visitedValues: ValueSet
+
+  var roots: SingleInlineArray<Value> = SingleInlineArray<Value>()
+
+  init(_ context: Context, scopedValue: Value) {
+    self.context = context
+    self.isTrivialScope = scopedValue.type.isAddress
+      ? scopedValue.type.objectType.isTrivial(in: scopedValue.parentFunction)
+      : scopedValue.isTrivial(context)
+    self.visitedValues = ValueSet(context)
+  }
+
+  mutating func deinitialize() {
+    visitedValues.deinitialize()
+  }
+ 
+  mutating func introducer(_ value: Value, _ owner: Value?) -> WalkResult {
+    roots.push(value)
+    return .continueWalk
+  }
+
+  mutating func addressIntroducer(_ address: Value, access: AccessBaseAndScopes) -> WalkResult {
+    roots.push(address)
+    return .continueWalk
+  }
+
+  mutating func needWalk(for value: Value, _ owner: Value?) -> Bool {
+    visitedValues.insert(value)
+  }
+
+  mutating func needWalk(for address: Value) -> Bool {
+    visitedValues.insert(address)
+  }
+
+  mutating func walkUp(newLifetime: Value) -> WalkResult {
+    if newLifetime.type.isAddress {
+      return walkUp(address: newLifetime)
+    }
+    let newOwner = newLifetime.ownership == .owned ? newLifetime : nil
+    return walkUp(value: newLifetime, newOwner)
+  }
+}
+
+// =============================================================================
+// Unit tests
+// =============================================================================
+
+
 let lifetimeDependenceUseTest = FunctionTest("lifetime_dependence_use") {
     function, arguments, context in
   let value = arguments.takeValue()
@@ -1087,6 +1478,18 @@ let lifetimeDependenceUseTest = FunctionTest("lifetime_dependence_use") {
   _ = printer.walkDown(dependence: dependence)
 }
 
+let lifetimeDependenceRootTest = FunctionTest("lifetime_dependence_root") {
+    function, arguments, context in
+  let value = arguments.takeValue()
+  print("Lifetime dependence roots of: \(value)")
+  var walker = LifetimeDependenceRootWalker(context, scopedValue: value)
+  let result = walker.walkUp(newLifetime: value)
+  assert(result == .continueWalk)
+  for root in walker.roots {
+    print("root: \(root)")
+  }
+  walker.deinitialize()
+}
 
 // SIL Unit tests
 
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/LocalVariableUtils.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/LocalVariableUtils.swift
index 2736f60ca0531..e6fc197c40c43 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/LocalVariableUtils.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/LocalVariableUtils.swift
@@ -12,7 +12,7 @@
 ///
 /// SIL operates on three kinds of addressable memory:
 ///
-/// 1. Temporary RValues. These are recognied by AddressInitializationWalker. These largely disappear with opaque SIL
+/// 1. Temporary RValues. These are recognized by AddressInitializationWalker. These largely disappear with opaque SIL
 /// values.
 ///
 /// 2. Local variables. These are always introduced by either a VarDeclInstruction or a Function argument with non-nil
@@ -27,9 +27,9 @@ import SIL
 
 private let verbose = false
 
-private func log(_ message: @autoclosure () -> String) {
+private func log(prefix: Bool = true, _ message: @autoclosure () -> String) {
   if verbose {
-    print("### \(message())")
+    debugLog(prefix: prefix, message())
   }
 }
 
@@ -69,8 +69,10 @@ struct LocalVariableAccess: CustomStringConvertible {
     case dependenceSource // A value/address depends on this local here (like a load)
     case dependenceDest  // This local depends on another value/address here (like a store)
     case store       // 'var' initialization and destruction
+    case storeBorrow // scoped initialization of temporaries
     case apply       // indirect arguments
     case escape      // alloc_box captures
+    case deadEnd     // unreachable
   }
   let kind: Kind
   // All access have an operand except .incomingArgument and .outgoingArgument.
@@ -101,9 +103,9 @@ struct LocalVariableAccess: CustomStringConvertible {
       case .`init`, .modify:
         return true
       }
-    case .load, .dependenceSource, .dependenceDest:
+    case .load, .dependenceSource, .dependenceDest, .deadEnd:
       return false
-    case .incomingArgument, .outgoingArgument, .store, .inoutYield:
+    case .incomingArgument, .outgoingArgument, .store, .storeBorrow, .inoutYield:
       return true
     case .apply:
       let apply = instruction as! FullApplySite
@@ -146,10 +148,14 @@ struct LocalVariableAccess: CustomStringConvertible {
       str += "dependenceDest"
     case .store:
       str += "store"
+    case .storeBorrow:
+      str += "storeBorrow"
     case .apply:
       str += "apply"
     case .escape:
       str += "escape"
+    case .deadEnd:
+      str += "deadEnd"
     }
     if let inst = instruction {
       str += "\(inst)"
@@ -178,9 +184,9 @@ class LocalVariableAccessInfo: CustomStringConvertible {
       case .`init`, .modify:
         break // lazily compute full assignment
       }
-      case .load, .dependenceSource, .dependenceDest:
+    case .load, .dependenceSource, .dependenceDest:
       self._isFullyAssigned = false
-    case .store:
+    case .store, .storeBorrow:
       if let store = localAccess.instruction as? StoringInstruction {
         self._isFullyAssigned = LocalVariableAccessInfo.isBase(address: store.destination)
       } else {
@@ -198,7 +204,7 @@ class LocalVariableAccessInfo: CustomStringConvertible {
       self.hasEscaped = true
     case .inoutYield:
       self._isFullyAssigned = false
-    case .incomingArgument, .outgoingArgument:
+    case .incomingArgument, .outgoingArgument, .deadEnd:
       fatalError("Function arguments are never mapped to LocalVariableAccessInfo")
     }
   }
@@ -226,7 +232,7 @@ class LocalVariableAccessInfo: CustomStringConvertible {
   }
 
   var description: String {
-    return "full-assign: \(_isFullyAssigned == nil ? "unknown" : String(describing: _isFullyAssigned!)), "
+    return "assign: \(_isFullyAssigned == nil ? "unknown" : String(describing: _isFullyAssigned!)), "
       + "\(access)"
   }
 
@@ -329,7 +335,7 @@ struct LocalVariableAccessMap: Collection, CustomStringConvertible {
   subscript(instruction: Instruction) -> LocalVariableAccessInfo? { accessMap[instruction] }
 
   var description: String {
-    "Access map:\n" + map({String(describing: $0)}).joined(separator: "\n")
+    "Access map for: \(allocation)\n" + map({String(describing: $0)}).joined(separator: "\n")
   }
 }
 
@@ -421,12 +427,17 @@ extension LocalVariableAccessWalker: AddressUseVisitor {
   // temporaries do not have access scopes, so we need to walk down any projection that may be used to initialize the
   // temporary.
   mutating func projectedAddressUse(of operand: Operand, into value: Value) -> WalkResult {
-    // Intercept mark_dependence destination to record an access point which can be used like a store when finding all
-    // uses that affect the base after the point that the dependence was marked.
     if let md = value as? MarkDependenceInst {
-      assert(operand == md.valueOperand)
-      visit(LocalVariableAccess(.dependenceDest, operand))
-      // walk down the forwarded address as usual...
+      if operand == md.valueOperand {
+        // Intercept mark_dependence destination to record an access point which can be used like a store when finding
+        // all uses that affect the base after the point that the dependence was marked.
+        visit(LocalVariableAccess(.dependenceDest, operand))
+        // walk down the forwarded address as usual...
+      } else {
+        // A dependence is similar to loading from its source. Downstream uses are not accesses of the original local.
+        visit(LocalVariableAccess(.dependenceSource, operand))
+        return .continueWalk
+      }
     }
     return walkDownAddressUses(address: value)
   }
@@ -442,6 +453,9 @@ extension LocalVariableAccessWalker: AddressUseVisitor {
     case is LoadBorrowInst:
       visit(LocalVariableAccess(.load, operand))
       return .continueWalk
+    case is StoreBorrowInst:
+      visit(LocalVariableAccess(.storeBorrow, operand))
+      return .continueWalk
     default:
       // A StoreBorrow should be guarded by an access scope.
       //
@@ -457,13 +471,18 @@ extension LocalVariableAccessWalker: AddressUseVisitor {
   mutating func leafAddressUse(of operand: Operand) -> WalkResult {
     switch operand.instruction {
     case is StoringInstruction, is SourceDestAddrInstruction, is DestroyAddrInst, is DeinitExistentialAddrInst,
-         is InjectEnumAddrInst, is SwitchEnumAddrInst, is TupleAddrConstructorInst, is InitBlockStorageHeaderInst,
-         is PackElementSetInst:
-      // Handle instructions that initialize both temporaries and local variables.
+         is InjectEnumAddrInst, is TupleAddrConstructorInst, is InitBlockStorageHeaderInst, is PackElementSetInst:
+      // Handle instructions that initialize both temporaries and local variables. If operand's address is the same as
+      // the local variable's address, then this fully kills operand liveness. The original value in operand's address
+      // cannot be used in any way.
       visit(LocalVariableAccess(.store, operand))
     case let md as MarkDependenceAddrInst:
       assert(operand == md.addressOperand)
       visit(LocalVariableAccess(.dependenceDest, operand))
+    case is SwitchEnumAddrInst:
+      // switch_enum_addr is truly a leaf address use. It does not produce a new value. But in every other respect it is
+      // like a load.
+      visit(LocalVariableAccess(.load, operand))
     case is DeallocStackInst:
       break
     default:
@@ -630,13 +649,17 @@ struct LocalVariableReachableAccess {
 
 // Find reaching assignments...
 extension LocalVariableReachableAccess {
-  // Gather all fully assigned accesses that reach `instruction`.
+  // Gather all fully assigned accesses that reach 'instruction'. If 'instruction' is itself a modify access, it is
+  // ignored and the nearest assignments above 'instruction' are still gathered.
   func gatherReachingAssignments(for instruction: Instruction, in accessStack: inout Stack<LocalVariableAccess>)
     -> Bool {
     var blockList = BasicBlockWorklist(context)
     defer { blockList.deinitialize() }
 
-    let initialEffect = backwardScanAccesses(before: instruction, accessStack: &accessStack)
+    var initialEffect: BlockEffect? = nil
+    if let prev = instruction.previous {
+      initialEffect = backwardScanAccesses(before: prev, accessStack: &accessStack)
+    }
     if !backwardPropagateEffect(in: instruction.parentBlock, effect: initialEffect, blockList: &blockList,
                                 accessStack: &accessStack) {
       return false
@@ -647,7 +670,7 @@ extension LocalVariableReachableAccess {
       // lattice: none -> read -> modify -> escape -> assign
       //
       // `blockInfo.effect` is the same as `currentEffect` returned by backwardScanAccesses, except when an early escape
-      // happens after an assign.
+      // happens below an assign, in which case we report the escape here.
       switch currentEffect {
       case .none, .read, .modify, .escape:
         break
@@ -695,10 +718,10 @@ extension LocalVariableReachableAccess {
         continue
       case .assign:
         accessStack.push(accessInfo.access)
-        break
       case .escape:
         break
       }
+      break
     }
     return currentEffect
   }
@@ -708,27 +731,33 @@ extension LocalVariableReachableAccess {
 extension LocalVariableReachableAccess {
   /// This performs a forward CFG walk to find known reachable uses from `assignment`. This ignores aliasing and
   /// escapes.
-  func gatherKnownReachableUses(from assignment: LocalVariableAccess,
+  ///
+  /// The known live range is the range in which the assigned value is valid and may be used by dependent values. It
+  /// includes the destroy or reassignment of the local.
+  func gatherKnownLifetimeUses(from assignment: LocalVariableAccess,
                                 in accessStack: inout Stack<LocalVariableAccess>) {
     if let modifyInst = assignment.instruction {
-      _ = gatherReachableUses(after: modifyInst, in: &accessStack, allowEscape: true)
+      _ = gatherReachableUses(after: modifyInst, in: &accessStack, lifetime: true)
+      return
     }
-    gatherKnownReachableUsesFromEntry(in: &accessStack)
+    gatherKnownLifetimeUsesFromEntry(in: &accessStack)
   }
 
   /// This performs a forward CFG walk to find known reachable uses from the function entry. This ignores aliasing and
   /// escapes.
-  private func gatherKnownReachableUsesFromEntry(in accessStack: inout Stack<LocalVariableAccess>) {
+  private func gatherKnownLifetimeUsesFromEntry(in accessStack: inout Stack<LocalVariableAccess>) {
     assert(accessMap.liveInAccess!.kind == .incomingArgument, "only an argument access is live in to the function")
     let firstInst = accessMap.function.entryBlock.instructions.first!
-    _ = gatherReachableUses(onOrAfter: firstInst, in: &accessStack, allowEscape: true)
+    _ = gatherReachableUses(onOrAfter: firstInst, in: &accessStack, lifetime: true)
   }
 
   /// This performs a forward CFG walk to find all reachable uses of `modifyInst`. `modifyInst` may be a `begin_access
   /// [modify]` or instruction that initializes the local variable.
   ///
-  /// Returns true if all possible reachable uses were visited. Returns false if any escapes may reach `modifyInst` are
-  /// reachable from `modifyInst`.
+  /// This does not include the destroy or reassignment of the value set by `modifyInst`.
+  ///
+  /// Returns true if all possible reachable uses were visited. Returns false if any escapes may reach `modifyInst` or
+  /// are reachable from `modifyInst`.
   ///
   /// This does not gather the escaping accesses themselves. When escapes are reachable, it also does not guarantee that
   /// previously reachable accesses are gathered.
@@ -748,37 +777,40 @@ extension LocalVariableReachableAccess {
     if accessInfo.hasEscaped! {
       return false
     }
-    return gatherReachableUses(after: modifyInst, in: &accessStack, allowEscape: false)
+    return gatherReachableUses(after: modifyInst, in: &accessStack, lifetime: false)
   }
 
   /// This performs a forward CFG walk to find all uses of this local variable reachable after `begin`.
   ///
-  /// If `allowEscape` is true, then this returns false if the walk ended early because of a reachable escape.
+  /// If `lifetime` is true, then this gathers the full known lifetime, including destroys and reassignments ignoring
+  /// escapes.
+  ///
+  /// If `lifetime` is false, then this returns `false` if the walk ended early because of a reachable escape.
   private func gatherReachableUses(after begin: Instruction, in accessStack: inout Stack<LocalVariableAccess>,
-                                   allowEscape: Bool) -> Bool {
+                                   lifetime: Bool) -> Bool {
     if let term = begin as? TermInst {
       for succ in term.successors {
-        if !gatherReachableUses(onOrAfter: succ.instructions.first!, in: &accessStack, allowEscape: allowEscape) {
+        if !gatherReachableUses(onOrAfter: succ.instructions.first!, in: &accessStack, lifetime: lifetime) {
           return false
         }
       }
       return true
     } else {
-      return gatherReachableUses(onOrAfter: begin.next!, in: &accessStack, allowEscape: allowEscape)
+      return gatherReachableUses(onOrAfter: begin.next!, in: &accessStack, lifetime: lifetime)
     }
   }
 
   /// This performs a forward CFG walk to find all uses of this local variable reachable after and including `begin`.
   ///
-  /// If `allowEscape` is true, then this returns false if the walk ended early because of a reachable escape.
+  /// If `lifetime` is true, then this returns false if the walk ended early because of a reachable escape.
   private func gatherReachableUses(onOrAfter begin: Instruction, in accessStack: inout Stack<LocalVariableAccess>,
-                                   allowEscape: Bool) -> Bool {
+                                   lifetime: Bool) -> Bool {
     var blockList = BasicBlockWorklist(context)
     defer { blockList.deinitialize() }
 
     let initialBlock = begin.parentBlock
-    let initialEffect = forwardScanAccesses(after: begin, accessStack: &accessStack, allowEscape: allowEscape)
-    if !allowEscape, initialEffect == .escape {
+    let initialEffect = forwardScanAccesses(after: begin, accessStack: &accessStack, lifetime: lifetime)
+    if !lifetime, initialEffect == .escape {
       return false
     }
     forwardPropagateEffect(in: initialBlock, blockInfo: blockMap[initialBlock], effect: initialEffect,
@@ -794,22 +826,22 @@ extension LocalVariableReachableAccess {
       case .none:
         break
       case .escape:
-        if !allowEscape {
+        if !lifetime {
           break
         }
         fallthrough
       case .read, .modify, .assign:
         let firstInst = block.instructions.first!
-        currentEffect = forwardScanAccesses(after: firstInst, accessStack: &accessStack, allowEscape: allowEscape)
+        currentEffect = forwardScanAccesses(after: firstInst, accessStack: &accessStack, lifetime: lifetime)
       }
-      if !allowEscape, currentEffect == .escape {
+      if !lifetime, currentEffect == .escape {
         return false
       }
       forwardPropagateEffect(in: block, blockInfo: blockInfo, effect: currentEffect, blockList: &blockList,
                              accessStack: &accessStack)
     }
-    log("\(accessMap)")
-    log("Reachable access:\n\(accessStack.map({ String(describing: $0)}).joined(separator: "\n"))")
+    log("\n\(accessMap)")
+    log(prefix: false, "Reachable access:\n\(accessStack.map({ String(describing: $0)}).joined(separator: "\n"))")
     return true
   }
 
@@ -826,6 +858,8 @@ extension LocalVariableReachableAccess {
       }
       if block.terminator.isFunctionExiting {
         accessStack.push(LocalVariableAccess(.outgoingArgument, block.terminator))
+      } else if block.successors.isEmpty {
+        accessStack.push(LocalVariableAccess(.deadEnd, block.terminator))
       } else {
         for successor in block.successors { blockList.pushIfNotVisited(successor) }
       }
@@ -835,9 +869,9 @@ extension LocalVariableReachableAccess {
   }
 
   // Check all instructions in this block after and including `begin`. Return a BlockEffect indicating the combined
-  // effects seen before stopping the scan. An .assign stops the scan. A .escape stops the scan if allowEscape is false.
+  // effects seen before stopping the scan. An .assign stops the scan. A .escape stops the scan if lifetime is false.
   private func forwardScanAccesses(after first: Instruction, accessStack: inout Stack<LocalVariableAccess>,
-                                   allowEscape: Bool)
+                                   lifetime: Bool)
     -> BlockEffect? {
     var currentEffect: BlockEffect?
     for inst in InstructionList(first: first) {
@@ -847,9 +881,12 @@ extension LocalVariableReachableAccess {
       currentEffect = BlockEffect(for: accessInfo, accessMap.context).meet(currentEffect)
       switch currentEffect! {
       case .assign:
+        if lifetime {
+          accessStack.push(accessInfo.access)
+        }
         return currentEffect
       case .escape:
-        if !allowEscape {
+        if !lifetime {
           log("Local variable: \(accessMap.allocation)\n    escapes at \(inst)")
           return currentEffect
         }
@@ -873,7 +910,7 @@ extension LocalVariableReachableAccess {
   private func findAllEscapesPriorToAccess() {
     var visitedBlocks = BasicBlockSet(context)
     var escapedBlocks = BasicBlockSet(context)
-    var blockList = BasicBlockWorklist(context)
+    var blockList = Stack<BasicBlock>(context)
     defer {
       visitedBlocks.deinitialize()
       escapedBlocks.deinitialize()
@@ -886,19 +923,19 @@ extension LocalVariableReachableAccess {
       for successor in from.successors {
         if hasEscaped {
           if escapedBlocks.insert(successor) {
-            blockList.pushIfNotVisited(successor)
+            blockList.push(successor)
           }
         } else if visitedBlocks.insert(successor) {
-          blockList.pushIfNotVisited(successor)
+          blockList.push(successor)
         }
       }
     }
     var hasEscaped = propagateEscapeInBlock(after: accessMap.allocation.nextInstruction, hasEscaped: false)
     forwardPropagate(accessMap.allocation.parentBlock, hasEscaped)
     while let block = blockList.pop() {
-      hasEscaped = escapedBlocks.insert(block)
+      hasEscaped = escapedBlocks.contains(block)
       hasEscaped = propagateEscapeInBlock(after: block.instructions.first!, hasEscaped: hasEscaped)
-      forwardPropagate(accessMap.allocation.parentBlock, hasEscaped)
+      forwardPropagate(block, hasEscaped)
     }
   }
 
@@ -917,3 +954,49 @@ extension LocalVariableReachableAccess {
     return hasEscaped
   }
 }
+
+let localVariableReachingAssignmentsTest = FunctionTest("local_variable_reaching_assignments") {
+  function, arguments, context in
+  let allocation = arguments.takeValue()
+  let instruction = arguments.takeInstruction()
+  print("### Allocation: \(allocation)")
+  let localReachabilityCache = LocalVariableReachabilityCache()
+  guard let localReachability = localReachabilityCache.reachability(for: allocation, context) else {
+    print("No reachability")
+    return
+  }
+  print("### Access map:")
+  print(localReachability.accessMap)
+  print("### Instruction: \(instruction)")
+  var reachingAssignments = Stack<LocalVariableAccess>(context)
+  defer { reachingAssignments.deinitialize() }
+  guard localReachability.gatherReachingAssignments(for: instruction, in: &reachingAssignments) else {
+    print("!!! Reaching escape")
+    return
+  }
+  print("### Reachable assignments:")
+  print(reachingAssignments.map({ String(describing: $0)}).joined(separator: "\n"))
+}
+
+let localVariableReachableUsesTest = FunctionTest("local_variable_reachable_uses") {
+  function, arguments, context in
+  let allocation = arguments.takeValue()
+  let modify = arguments.takeInstruction()
+  print("### Allocation: \(allocation)")
+  let localReachabilityCache = LocalVariableReachabilityCache()
+  guard let localReachability = localReachabilityCache.reachability(for: allocation, context) else {
+    print("No reachability")
+    return
+  }
+  print("### Access map:")
+  print(localReachability.accessMap)
+  print("### Modify: \(modify)")
+  var reachableUses = Stack<LocalVariableAccess>(context)
+  defer { reachableUses.deinitialize() }
+  guard localReachability.gatherAllReachableUses(of: modify, in: &reachableUses) else {
+    print("!!! Reachable escape")
+    return
+  }
+  print("### Reachable access:")
+  print(reachableUses.map({ String(describing: $0)}).joined(separator: "\n"))
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/OptUtils.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/OptUtils.swift
index 6173adaf24e75..801c0fbf2ce9a 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/OptUtils.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/OptUtils.swift
@@ -45,6 +45,18 @@ extension Value {
     }
   }
 
+  var lookThroughIndexScalarCast: Value {
+    if let castBuiltin = self as? BuiltinInst {
+      switch castBuiltin.id {
+      case .TruncOrBitCast, .SExtOrBitCast:
+        return castBuiltin.arguments[0]
+      default:
+        return self
+      }
+    }
+    return self
+  }
+
   func isInLexicalLiverange(_ context: some Context) -> Bool {
     var worklist = ValueWorklist(context)
     defer { worklist.deinitialize() }
@@ -59,7 +71,7 @@ extension Value {
       }
       switch v {
       case let fw as ForwardingInstruction:
-        worklist.pushIfNotVisited(contentsOf: fw.definedOperands.lazy.map { $0.value })
+        worklist.pushIfNotVisited(contentsOf: fw.definedOperands.values)
       case let bf as BorrowedFromInst:
         worklist.pushIfNotVisited(bf.borrowedValue)
       case let bb as BeginBorrowInst:
@@ -70,7 +82,7 @@ extension Value {
         } else if let termResult = TerminatorResult(arg),
                let fw = termResult.terminator as? ForwardingInstruction
         {
-          worklist.pushIfNotVisited(contentsOf: fw.definedOperands.lazy.map { $0.value })
+          worklist.pushIfNotVisited(contentsOf: fw.definedOperands.values)
         }
       default:
         continue
@@ -113,20 +125,32 @@ extension Value {
     return true
   }
 
+  /// Project out a sub-field of this value according to `path`.
+  /// If this is an "owned" value the result is an "owned" value which forwards the original value.
+  /// This only works if _all_ non-trivial fields are projected. Otherwise some non-trivial results of
+  /// `destructure_struct` or `destructure_tuple` will be leaked.
   func createProjection(path: SmallProjectionPath, builder: Builder) -> Value {
     let (kind, index, subPath) = path.pop()
+    let result: Value
     switch kind {
     case .root:
       return self
     case .structField:
-      let structExtract = builder.createStructExtract(struct: self, fieldIndex: index)
-      return structExtract.createProjection(path: subPath, builder: builder)
+      if ownership == .owned {
+        result = builder.createDestructureStruct(struct: self).results[index]
+      } else {
+        result = builder.createStructExtract(struct: self, fieldIndex: index)
+      }
     case .tupleField:
-      let tupleExtract = builder.createTupleExtract(tuple: self, elementIndex: index)
-      return tupleExtract.createProjection(path: subPath, builder: builder)
+      if ownership == .owned {
+        result = builder.createDestructureTuple(tuple: self).results[index]
+      } else {
+        result = builder.createTupleExtract(tuple: self, elementIndex: index)
+      }
     default:
       fatalError("path is not materializable")
     }
+    return result.createProjection(path: subPath, builder: builder)
   }
 
   func createAddressProjection(path: SmallProjectionPath, builder: Builder) -> Value {
@@ -238,6 +262,18 @@ extension Builder {
     }
   }
 
+  static func insertCleanupAtFunctionExits(
+    of function: Function,
+    _ context: some MutatingContext,
+    insert: (Builder) -> ()
+  ) {
+    for exitBlock in function.blocks where exitBlock.terminator.isFunctionExiting {
+      let terminator = exitBlock.terminator
+      let builder = Builder(before: terminator, location: terminator.location.asCleanup, context)
+      insert(builder)
+    }
+  }
+
   func destroyCapturedArgs(for paiOnStack: PartialApplyInst) {
     precondition(paiOnStack.isOnStack, "Function must only be called for `partial_apply`s on stack!")
     self.bridged.destroyCapturedArgs(paiOnStack.bridged)
@@ -329,14 +365,6 @@ extension Value {
   }
 }
 
-extension SingleValueInstruction {
-  /// Replaces all uses with `replacement` and then erases the instruction.
-  func replace(with replacement: Value, _ context: some MutatingContext) {
-    uses.replaceAll(with: replacement, context)
-    context.erase(instruction: self)
-  }
-}
-
 extension Instruction {
   var isTriviallyDead: Bool {
     if results.contains(where: { !$0.uses.isEmpty }) {
@@ -387,8 +415,7 @@ extension Instruction {
     case let bi as BuiltinInst:
       switch bi.id {
       case .ZeroInitializer:
-        let type = bi.type.isBuiltinVector ? bi.type.builtinVectorElementType : bi.type
-        return type.isBuiltinInteger || type.isBuiltinFloat
+        return bi.arguments.count == 0
       case .PtrToInt:
         return bi.operands[0].value is StringLiteralInst
       case .IntToPtr:
@@ -456,7 +483,7 @@ extension Instruction {
     }
   }
 
-  /// Returns true if `otherInst` is in the same block and dominated by this instruction.
+  /// Returns true if `otherInst` is in the same block and is strictly dominated by this instruction.
   /// To be used as simple dominance check if both instructions are most likely located in the same block
   /// and no DominatorTree is available (like in instruction simplification).
   func dominatesInSameBlock(_ otherInst: Instruction) -> Bool {
@@ -481,6 +508,22 @@ extension Instruction {
     }
     return false
   }
+  
+  /// Returns true if `otherInst` is in the same block and is strictly dominated by this instruction or
+  /// the parent block of the instruction dominates parent block of `otherInst`.
+  func dominates(
+    _ otherInst: Instruction,
+    _ domTree: DominatorTree
+  ) -> Bool {
+    if parentBlock == otherInst.parentBlock {
+      return dominatesInSameBlock(otherInst)
+    } else {
+      return parentBlock.dominates(
+        otherInst.parentBlock,
+        domTree
+      )
+    }
+  }
 
   /// If this instruction uses a (single) existential archetype, i.e. it has a type-dependent operand,
   /// returns the concrete type if it is known.
@@ -580,36 +623,22 @@ extension StoreInst {
 extension LoadInst {
   @discardableResult
   func trySplit(_ context: FunctionPassContext) -> Bool {
-    var elements = [Value]()
-    let builder = Builder(before: self, context)
     if type.isStruct {
-      if (type.nominal as! StructDecl).hasUnreferenceableStorage {
-        return false
-      }
-      guard let fields = type.getNominalFields(in: parentFunction) else {
+      guard !(type.nominal as! StructDecl).hasUnreferenceableStorage,
+            let fields = type.getNominalFields(in: parentFunction) else {
         return false
       }
-      for idx in 0..<fields.count {
-        let fieldAddr = builder.createStructElementAddr(structAddress: address, fieldIndex: idx)
-        let splitLoad = builder.createLoad(fromAddress: fieldAddr, ownership: self.splitOwnership(for: fieldAddr))
-        elements.append(splitLoad)
-      }
-      let newStruct = builder.createStruct(type: self.type, elements: elements)
-      self.replace(with: newStruct, context)
+      
+      _ = splitStruct(fields: fields, context)
+      
       return true
     } else if type.isTuple {
-      var elements = [Value]()
-      let builder = Builder(before: self, context)
-      for idx in 0..<type.tupleElements.count {
-        let fieldAddr = builder.createTupleElementAddr(tupleAddress: address, elementIndex: idx)
-        let splitLoad = builder.createLoad(fromAddress: fieldAddr, ownership: self.splitOwnership(for: fieldAddr))
-        elements.append(splitLoad)
-      }
-      let newTuple = builder.createTuple(type: self.type, elements: elements)
-      self.replace(with: newTuple, context)
+      _ = splitTuple(context)
+      
       return true
+    } else {
+      return false
     }
-    return false
   }
 
   private func splitOwnership(for fieldValue: Value) -> LoadOwnership {
@@ -620,6 +649,70 @@ extension LoadInst {
       return fieldValue.type.isTrivial(in: parentFunction) ? .trivial : self.loadOwnership
     }
   }
+  
+  func trySplit(
+    alongPath projectionPath: SmallProjectionPath,
+    _ context: FunctionPassContext
+  ) -> [LoadInst]? {
+    if projectionPath.isEmpty {
+      return nil
+    }
+    
+    let (fieldKind, index, pathRemainder) = projectionPath.pop()
+    
+    var elements: [LoadInst]
+    
+    switch fieldKind {
+    case .structField where type.isStruct:
+      guard !(type.nominal as! StructDecl).hasUnreferenceableStorage,
+            let fields = type.getNominalFields(in: parentFunction) else {
+        return nil
+      }
+      
+      elements = splitStruct(fields: fields, context)
+    case .tupleField where type.isTuple:
+      elements = splitTuple(context)
+    default:
+      return nil
+    }
+    
+    if let recursiveSplitLoad = elements[index].trySplit(alongPath: pathRemainder, context) {
+      elements.remove(at: index)
+      elements += recursiveSplitLoad
+    }
+    
+    return elements
+  }
+  
+  private func splitStruct(fields: NominalFieldsArray, _ context: FunctionPassContext) -> [LoadInst] {
+    var elements = [LoadInst]()
+    let builder = Builder(before: self, context)
+    
+    for idx in 0..<fields.count {
+      let fieldAddr = builder.createStructElementAddr(structAddress: address, fieldIndex: idx)
+      let splitLoad = builder.createLoad(fromAddress: fieldAddr, ownership: self.splitOwnership(for: fieldAddr))
+      elements.append(splitLoad)
+    }
+    let newStruct = builder.createStruct(type: self.type, elements: elements)
+    self.replace(with: newStruct, context)
+    
+    return elements
+  }
+  
+  private func splitTuple(_ context: FunctionPassContext) -> [LoadInst] {
+    var elements = [LoadInst]()
+    let builder = Builder(before: self, context)
+    
+    for idx in 0..<type.tupleElements.count {
+      let fieldAddr = builder.createTupleElementAddr(tupleAddress: address, elementIndex: idx)
+      let splitLoad = builder.createLoad(fromAddress: fieldAddr, ownership: self.splitOwnership(for: fieldAddr))
+      elements.append(splitLoad)
+    }
+    let newTuple = builder.createTuple(type: self.type, elements: elements)
+    self.replace(with: newTuple, context)
+    
+    return elements
+  }
 }
 
 extension FunctionPassContext {
@@ -751,11 +844,14 @@ private struct EscapesToValueVisitor : EscapeVisitor {
 }
 
 extension Function {
+  /// Analyzes the global initializer function and returns global it initializes (from `alloc_global` instruction).
   var initializedGlobal: GlobalVariable? {
-    if !isGlobalInitOnceFunction {
+    guard isGlobalInitOnceFunction,
+          let firstBlock = blocks.first
+    else {
       return nil
     }
-    for inst in entryBlock.instructions {
+    for inst in firstBlock.instructions {
       if let allocGlobal = inst as? AllocGlobalInst {
         return allocGlobal.global
       }
@@ -826,7 +922,7 @@ extension GlobalVariable {
 
 extension InstructionRange {
   /// Adds the instruction range of a borrow-scope by transitively visiting all (potential) re-borrows.
-  mutating func insert(borrowScopeOf borrow: BorrowIntroducingInstruction, _ context: some Context) {
+  mutating func insert(borrowScopeOf borrow: BeginBorrowInstruction, _ context: some Context) {
     var worklist = ValueWorklist(context)
     defer { worklist.deinitialize() }
 
@@ -846,77 +942,6 @@ extension InstructionRange {
   }
 }
 
-/// Analyses the global initializer function and returns the `alloc_global` and `store`
-/// instructions which initialize the global.
-/// Returns nil if `function` has any side-effects beside initializing the global.
-///
-/// The function's single basic block must contain following code pattern:
-/// ```
-///   alloc_global @the_global
-///   %a = global_addr @the_global
-///   %i = some_const_initializer_insts
-///   store %i to %a
-/// ```
-/// 
-/// For all other instructions `handleUnknownInstruction` is called and such an instruction
-/// is accepted if `handleUnknownInstruction` returns true.
-func getGlobalInitialization(
-  of function: Function,
-  _ context: some Context,
-  handleUnknownInstruction: (Instruction) -> Bool
-) -> (allocInst: AllocGlobalInst, storeToGlobal: StoreInst)? {
-  guard let block = function.blocks.singleElement else {
-    return nil
-  }
-
-  var allocInst: AllocGlobalInst? = nil
-  var globalAddr: GlobalAddrInst? = nil
-  var store: StoreInst? = nil
-
-  for inst in block.instructions {
-    switch inst {
-    case is ReturnInst,
-         is DebugValueInst,
-         is DebugStepInst,
-         is BeginAccessInst,
-         is EndAccessInst:
-      continue
-    case let agi as AllocGlobalInst:
-      if allocInst == nil {
-        allocInst = agi
-        continue
-      }
-    case let ga as GlobalAddrInst:
-      if let agi = allocInst, agi.global == ga.global {
-        globalAddr = ga
-      }
-      continue
-    case let si as StoreInst:
-      if store == nil,
-         let ga = globalAddr,
-         si.destination == ga
-      {
-        store = si
-        continue
-      }
-    // Note that the initializer must not contain a `global_value` because `global_value` needs to
-    // initialize the class metadata at runtime.
-    default:
-      if inst.isValidInStaticInitializerOfGlobal(context) {
-        continue
-      }
-    }
-    if handleUnknownInstruction(inst) {
-      continue
-    }
-    return nil
-  }
-  if let store = store {
-    return (allocInst: allocInst!, storeToGlobal: store)
-  }
-  return nil
-}
-
 func canDynamicallyCast(from sourceType: CanonicalType, to destType: CanonicalType,
                         in function: Function, sourceTypeIsExact: Bool
 ) -> Bool? {
@@ -941,27 +966,74 @@ extension CheckedCastAddrBranchInst {
 
 extension CopyAddrInst {
   @discardableResult
-  func replaceWithLoadAndStore(_ context: some MutatingContext) -> StoreInst {
-    let loadOwnership: LoadInst.LoadOwnership
-    let storeOwnership: StoreInst.StoreOwnership
-    if parentFunction.hasOwnership {
-      if source.type.isTrivial(in: parentFunction) {
-        loadOwnership = .trivial
-        storeOwnership = .trivial
-      } else {
-        loadOwnership = isTakeOfSrc ? .take : .copy
-        storeOwnership = isInitializationOfDest ? .initialize : .assign
+  func trySplit(_ context: FunctionPassContext) -> Bool {
+    let builder = Builder(before: self, context)
+    if source.type.isStruct {
+      if (source.type.nominal as! StructDecl).hasUnreferenceableStorage {
+        return false
       }
-    } else {
-      loadOwnership = .unqualified
-      storeOwnership = .unqualified
+      guard let fields = source.type.getNominalFields(in: parentFunction) else {
+        return false
+      }
+      for idx in 0..<fields.count {
+        let srcFieldAddr = builder.createStructElementAddr(structAddress: source, fieldIndex: idx)
+        let destFieldAddr = builder.createStructElementAddr(structAddress: destination, fieldIndex: idx)
+        builder.createCopyAddr(from: srcFieldAddr, to: destFieldAddr,
+                               takeSource: isTake(for: srcFieldAddr), initializeDest: isInitializationOfDestination)
+      }
+      context.erase(instruction: self)
+      return true
+    } else if source.type.isTuple {
+      let builder = Builder(before: self, context)
+      for idx in 0..<source.type.tupleElements.count {
+        let srcFieldAddr = builder.createTupleElementAddr(tupleAddress: source, elementIndex: idx)
+        let destFieldAddr = builder.createTupleElementAddr(tupleAddress: destination, elementIndex: idx)
+        builder.createCopyAddr(from: srcFieldAddr, to: destFieldAddr,
+                               takeSource: isTake(for: srcFieldAddr), initializeDest: isInitializationOfDestination)
+      }
+      context.erase(instruction: self)
+      return true
     }
-    
+    return false
+  }
+
+  private func isTake(for fieldValue: Value) -> Bool {
+    return isTakeOfSource && !fieldValue.type.objectType.isTrivial(in: parentFunction)
+  }
+
+  @discardableResult
+  func replaceWithLoadAndStore(_ context: some MutatingContext) -> (load: LoadInst, store: StoreInst) {
     let builder = Builder(before: self, context)
-    let value = builder.createLoad(fromAddress: source, ownership: loadOwnership)
-    let store = builder.createStore(source: value, destination: destination, ownership: storeOwnership)
+    let load = builder.createLoad(fromAddress: source, ownership: loadOwnership)
+    let store = builder.createStore(source: load, destination: destination, ownership: storeOwnership)
     context.erase(instruction: self)
-    return store
+    return (load, store)
+  }
+
+  var loadOwnership: LoadInst.LoadOwnership {
+    if !parentFunction.hasOwnership {
+      return .unqualified
+    }
+    if type.isTrivial(in: parentFunction) {
+      return .trivial
+    }
+    if isTakeOfSource {
+      return .take
+    }
+    return .copy
+  }
+
+  var storeOwnership: StoreInst.StoreOwnership {
+    if !parentFunction.hasOwnership {
+      return .unqualified
+    }
+    if type.isTrivial(in: parentFunction) {
+      return .trivial
+    }
+    if isInitializationOfDestination {
+      return .initialize
+    }
+    return .assign
   }
 }
 
@@ -983,6 +1055,81 @@ extension Type {
     if !context.options.useAggressiveReg2MemForCodeSize {
       return true
     }
-    return context._bridged.shouldExpand(self.bridged)
+    return context.bridgedPassContext.shouldExpand(self.bridged)
+  }
+}
+
+/// Used by TempLValueElimination and TempRValueElimination to make the optimization work by both,
+/// `copy_addr` and `load`-`store`-pairs.
+protocol CopyLikeInstruction: Instruction {
+  var sourceAddress: Value { get }
+  var destinationAddress: Value { get }
+  var isTakeOfSource: Bool { get }
+  var isInitializationOfDestination: Bool { get }
+  var loadingInstruction: Instruction { get }
+}
+
+extension CopyAddrInst: CopyLikeInstruction {
+  var sourceAddress: Value { source }
+  var destinationAddress: Value { destination }
+  var loadingInstruction: Instruction { self }
+}
+
+// A `store` which has a `load` as source operand. This is basically the same as a `copy_addr`.
+extension StoreInst: CopyLikeInstruction {
+  var sourceAddress: Value { load.address }
+  var destinationAddress: Value { destination }
+  var isTakeOfSource: Bool { load.loadOwnership == .take }
+  var isInitializationOfDestination: Bool { storeOwnership != .assign }
+  var loadingInstruction: Instruction { load }
+  private var load: LoadInst { source as! LoadInst }
+}
+
+func eraseIfDead(functions: [Function], _ context: ModulePassContext) {
+  var toDelete = functions
+  while true {
+    var remaining = [Function]()
+    for fn in toDelete {
+      if !fn.isPossiblyUsedExternally && !fn.isReferencedInModule {
+        context.erase(function: fn)
+      } else {
+        remaining.append(fn)
+      }
+    }
+    if remaining.count == toDelete.count {
+      return
+    }
+    toDelete = remaining
+  }
+}
+
+func isInLoop(block startBlock: BasicBlock, _ context: FunctionPassContext) -> Bool {
+  var worklist = BasicBlockWorklist(context)
+  defer { worklist.deinitialize() }
+
+  worklist.pushIfNotVisited(contentsOf: startBlock.successors)
+  while let block = worklist.pop() {
+    if block == startBlock {
+      return true
+    }
+    worklist.pushIfNotVisited(contentsOf: block.successors)
   }
+  return false
+}
+
+func cloneFunction(from originalFunction: Function, toEmpty targetFunction: Function, _ context: FunctionPassContext) {
+  var cloner = Cloner(cloneToEmptyFunction: targetFunction, context)
+  defer { cloner.deinitialize() }
+  cloner.cloneFunctionBody(from: originalFunction)
+}
+
+func cloneAndSpecializeFunction(from originalFunction: Function,
+                                toEmpty targetFunction: Function,
+                                substitutions: SubstitutionMap,
+                                _ context: FunctionPassContext
+) {
+  var cloner = TypeSubstitutionCloner(fromFunction: originalFunction, toEmptyFunction: targetFunction,
+                                      substitutions: substitutions, context)
+  defer { cloner.deinitialize() }
+  cloner.cloneFunctionBody()
 }
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/OwnershipLiveness.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/OwnershipLiveness.swift
index ec3c03b82ccaf..ba61cf0b440e8 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/OwnershipLiveness.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/Utilities/OwnershipLiveness.swift
@@ -84,7 +84,27 @@ func computeKnownLiveness(for definingValue: Value, visitInnerUses: Bool = false
                                         visitInnerUses: visitInnerUses, context).acquireRange
 }
 
-/// If any interior pointer may escape, then record the first instance here. If 'ignoseEscape' is true, this
+/// Compute the live range for the borrow scopes of a guaranteed value. This returns a separate instruction range for
+/// each of the value's borrow introducers.
+///
+/// TODO: This should return a single multiply-defined instruction range.
+func computeBorrowLiveRange(for value: Value, _ context: FunctionPassContext)
+  -> SingleInlineArray<(BeginBorrowValue, InstructionRange)> {
+  assert(value.ownership == .guaranteed)
+
+  var ranges = SingleInlineArray<(BeginBorrowValue, InstructionRange)>()
+  // If introducers is empty, then the dependence is on a trivial value, so
+  // there is no ownership range.
+  for beginBorrow in value.getBorrowIntroducers(context) {
+    /// FIXME: Remove calls to computeKnownLiveness() as soon as lifetime completion runs immediately after
+    /// SILGen. Instead, this should compute linear liveness for borrowed value by switching over BeginBorrowValue, just
+    /// like LifetimeDependence.Scope.computeRange().
+    ranges.push((beginBorrow, computeKnownLiveness(for: beginBorrow.value, context)))
+  }
+  return ranges
+}
+
+/// If any interior pointer may escape, then record the first instance here. If 'ignoreEscape' is true, this
 /// immediately aborts the walk, so further instances are unavailable.
 ///
 /// .escaping may either be a non-address operand with
@@ -685,7 +705,7 @@ extension InteriorUseWalker: AddressUseVisitor {
       if handleInner(borrowed: ba) == .abortWalk {
         return .abortWalk
       }
-      return ba.endOperands.walk { useVisitor($0) }
+      return ba.scopeEndingOperands.walk { useVisitor($0) }
     case let ba as BeginApplyInst:
       if handleInner(borrowed: ba.token) == .abortWalk {
         return .abortWalk
@@ -697,7 +717,7 @@ extension InteriorUseWalker: AddressUseVisitor {
       if handleInner(borrowed: sb) == .abortWalk {
         return .abortWalk
       }
-      return sb.uses.filterUsers(ofType: EndBorrowInst.self).walk {
+      return sb.uses.filterUses(ofType: EndBorrowInst.self).walk {
         useVisitor($0)
       }
     case let load as LoadBorrowInst:
@@ -786,6 +806,10 @@ extension InteriorUseWalker {
     if let inst = operand.instruction as? ForwardingInstruction {
       return inst.forwardedResults.walk { walkDownUses(of: $0) }
     }
+    // TODO: Represent apply of borrow accessors as ForwardingOperation and use that over ForwardingInstruction
+    if let apply = operand.instruction as? FullApplySite, apply.hasGuaranteedResult {
+      return walkDownUses(of: apply.singleDirectResult!)
+    }
     // TODO: verify that ForwardInstruction handles all .forward operand ownership and assert that only phis can be
     // reached: assert(Phi(using: operand) != nil)
     return .continueWalk
@@ -904,3 +928,29 @@ let interiorLivenessTest = FunctionTest("interior_liveness_swift") {
   defer { boundary.deinitialize() }
   print(boundary)
 }
+
+//
+// TODO: Move this to InstructionRange.swift when computeLinearLiveness is in the SIL module.
+//
+let rangeOverlapsPathTest = FunctionTest("range_overlaps_path") {
+  function, arguments, context in
+  let rangeValue = arguments.takeValue()
+  print("Range of: \(rangeValue)")
+  var range = computeLinearLiveness(for: rangeValue, context)
+  defer { range.deinitialize() }
+  let pathInst = arguments.takeInstruction()
+  print("Path begin: \(pathInst)")
+  if let pathBegin = pathInst as? ScopedInstruction {
+    for end in pathBegin.endInstructions {
+      print("Overlap kind:", range.overlaps(pathBegin: pathInst, pathEnd: end, context))
+    }
+    return
+  }
+  if let pathValue = pathInst as? SingleValueInstruction, pathValue.ownership == .owned {
+    for end in pathValue.uses.endingLifetime {
+      print("Overlap kind:", range.overlaps(pathBegin: pathInst, pathEnd: end.instruction, context))
+    }
+    return
+  }
+  print("Test specification error: not a scoped or owned instruction: \(pathInst)")
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/SSAUpdater.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/SSAUpdater.swift
deleted file mode 100644
index 7b1d0f88c4d28..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/SSAUpdater.swift
+++ /dev/null
@@ -1,53 +0,0 @@
-//===--- SSAUpdater.swift -------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import SIL
-import OptimizerBridging
-
-/// Utility for updating SSA for a set of SIL instructions defined in multiple blocks.
-struct SSAUpdater<Context: MutatingContext> {
-  let context: Context
-
-  init(function: Function, type: Type, ownership: Ownership,
-       _ context: Context) {
-    self.context = context
-    context._bridged.SSAUpdater_initialize(function.bridged, type.bridged,
-                                           ownership._bridged)
-  }
-
-  mutating func addAvailableValue(_ value: Value, in block: BasicBlock) {
-    context._bridged.SSAUpdater_addAvailableValue(block.bridged, value.bridged)
-  }
-
-  /// Construct SSA for a value that is live at the *end* of a basic block.
-  mutating func getValue(atEndOf block: BasicBlock) -> Value {
-    context.notifyInstructionsChanged()
-    return context._bridged.SSAUpdater_getValueAtEndOfBlock(block.bridged).value
-  }
-
-  /// Construct SSA for a value that is live in the *middle* of a block.
-  /// This handles the case where the use is before a definition of the value in the same block.
-  ///
-  ///   bb1:
-  ///     %1 = def
-  ///     br bb2
-  ///   bb2:
-  ///       = use(?)
-  ///    %2 = def
-  ///    cond_br bb2, bb3
-  ///
-  /// In this case we need to insert a phi argument in bb2, merging %1 and %2.
-  mutating func getValue(inMiddleOf block: BasicBlock) -> Value {
-    context.notifyInstructionsChanged()
-    return context._bridged.SSAUpdater_getValueInMiddleOfBlock(block.bridged).value
-  }
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/SpecializationCloner.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/SpecializationCloner.swift
deleted file mode 100644
index 28a8240d46998..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/SpecializationCloner.swift
+++ /dev/null
@@ -1,49 +0,0 @@
-//===--- SpecializationCloner.swift --------------------------------------------==//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import OptimizerBridging
-import SIL
-
-/// Utility cloner type that can be used by optimizations that generate new functions or specialized versions of
-/// existing functions. 
-struct SpecializationCloner {
-  private let bridged: BridgedSpecializationCloner
-  let context: FunctionPassContext
-
-  init(emptySpecializedFunction: Function, _ context: FunctionPassContext) {
-    self.bridged = BridgedSpecializationCloner(emptySpecializedFunction.bridged)
-    self.context = context
-  }
-  
-  var cloned: Function {
-    bridged.getCloned().function
-  }
-
-  var entryBlock: BasicBlock {
-    if cloned.blocks.isEmpty {
-      return cloned.appendNewBlock(context)
-    } else {
-      return cloned.entryBlock
-    }
-  }
-
-  func getClonedBlock(for originalBlock: BasicBlock) -> BasicBlock {
-    bridged.getClonedBasicBlock(originalBlock.bridged).block
-  }
-
-  func cloneFunctionBody(from originalFunction: Function, entryBlockArguments: [Value]) {
-    entryBlockArguments.withBridgedValues { bridgedEntryBlockArgs in
-      bridged.cloneFunctionBody(originalFunction.bridged, self.entryBlock.bridged, bridgedEntryBlockArgs)
-    }
-  }
-
-}
\ No newline at end of file
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/StaticInitCloner.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/StaticInitCloner.swift
deleted file mode 100644
index dcc9853052c6a..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/StaticInitCloner.swift
+++ /dev/null
@@ -1,78 +0,0 @@
-//===--- StaticInitCloner.swift --------------------------------------------==//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import SIL
-import OptimizerBridging
-
-/// Clones the initializer value of a GlobalVariable.
-///
-/// Used to transitively clone "constant" instructions, including their operands,
-/// from or to the static initializer value of a GlobalVariable.
-///
-struct StaticInitCloner<Context: MutatingContext> {
-  private var bridged: BridgedCloner
-  private let context: Context
-  private let cloningIntoFunction: Bool
-
-  init(cloneTo global: GlobalVariable, _ context: Context) {
-    self.bridged = BridgedCloner(global.bridged, context._bridged)
-    self.context = context
-    self.cloningIntoFunction = false
-  }
-
-  init(cloneBefore inst: Instruction, _ context: Context) {
-    self.bridged = BridgedCloner(inst.bridged, context._bridged)
-    self.context = context
-    self.cloningIntoFunction = true
-  }
-
-  mutating func deinitialize() {
-    bridged.destroy(context._bridged)
-  }
-
-  /// Transitively clones `value` including its defining instruction's operands.
-  mutating func clone(_ value: Value) -> Value {
-
-    if isCloned(value: value) {
-      return getClonedValue(of: value)
-    }
-
-    if let beginAccess = value as? BeginAccessInst {
-      // Skip access instructions, which might be generated for UnsafePointer globals which point to other globals.
-      let clonedOperand = clone(beginAccess.address)
-      bridged.recordFoldedValue(beginAccess.bridged, clonedOperand.bridged)
-      return clonedOperand
-    }
-
-    let inst = value.definingInstruction!
-    assert(!(inst is ScopedInstruction), "global init value must not contain a scoped instruction")
-
-    for op in inst.operands {
-      _ = clone(op.value)
-    }
-
-    bridged.clone(inst.bridged)
-    let clonedValue = getClonedValue(of: value)
-    if cloningIntoFunction {
-      context.notifyInstructionChanged(clonedValue.definingInstruction!)
-    }
-    return clonedValue
-  }
-
-  mutating func getClonedValue(of value: Value) -> Value {
-    bridged.getClonedValue(value.bridged).value
-  }
-
-  func isCloned(value: Value) -> Bool {
-    bridged.isValueCloned(value.bridged)
-  }
-}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/Test.swift b/SwiftCompilerSources/Sources/Optimizer/Utilities/Test.swift
deleted file mode 100644
index 101beb34b03dc..0000000000000
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/Test.swift
+++ /dev/null
@@ -1,276 +0,0 @@
-//===----------- Test.swift - In-IR tests from Swift source ---------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-//
-// TO ADD A NEW TEST, just add a new FunctionTest instance.
-// - In the source file containing the functionality you want to test:
-//       let myNewTest = 
-//       FunctionTest("my_new_test") { function, arguments, context in
-//       }
-// - In SwiftCompilerSources/Sources/SIL/Test.swift's registerOptimizerTests
-//   function, add a new argument to the variadic function:
-//       registerFunctionTests(..., myNewTest)
-//
-//===----------------------------------------------------------------------===//
-//
-// TO TROUBLESHOOT A NEW TEST, consider the following scenarios:
-// - PROBLEM: The test isn't running on PLATFORM and the failure says
-//
-//                Found no test named my_new_test.
-//
-//   SOLUTION: Is this a platform one that doesn't use SwiftCompilerSources
-//             (e.g. Windows)?  Then add
-//
-//                 // REQUIRES: swift_in_compiler
-//
-//             to the test file.
-//   EXPLANATION: The tests written within SwiftCompilerSources only get built
-//                and registered on platforms where the SwiftCompilerSources are
-//                built and used.
-//
-//===----------------------------------------------------------------------===//
-//
-// Provides a mechanism for writing tests against compiler code in the context
-// of a function.  The goal is to get the same effect as calling a function and
-// checking its output.
-//
-// This is done via the specify_test instruction.  Using one or more instances
-// of it in your test case's SIL function, you can specify which test (instance
-// of FunctionTest) should be run and what arguments should be provided to it.
-// For full details of the specify_test instruction's grammar, see SIL.rst.
-//
-// The test grabs the arguments it expects out of the TestArguments instance
-// it is provided.  It calls some function or functions.  It then prints out
-// interesting results.  These results can then be FileCheck'd.
-//
-// CASE STUDY:
-// Here's an example of how it works:
-// 0) A source file, NeatUtils.swift contains
-//
-//    fileprivate func myNeatoUtility(int: Int, value: Value, function: Function) { ... }
-//
-//    and
-//
-//    let myNeatoUtilityTest = 
-//    FunctionTest("my_neato_utility") { function, arguments, test in
-//         // The code here is described in detail below.
-//         // See 4).
-//         let count = arguments.takeInt()
-//         let target = arguments.takeValue()
-//         let callee = arguments.takeFunction()
-//         // See 5)
-//         myNeatoUtility(int: count, value: target, function: callee)
-//         // See 6)
-//         print(function)
-//      }
-// 1) A test test/SILOptimizer/interesting_functionality_unit.sil runs the
-//    TestRunner pass:
-//     // RUN: %target-sil-opt -test-runner %s -o /dev/null 2>&1 | %FileCheck %s
-//     // REQUIRES: swift_in_compiler
-// 2) A function in interesting_functionality_unit.sil contains the
-//    specify_test instruction.
-//      sil @f : $() -> () {
-//      ...
-//      specify_test "my_neato_utility 43 %2 @function[other_fun]"
-//      ...
-//      }
-// 3) TestRunner finds the FunctionTest instance myNeatoUtilityTest registered
-//    under the name "my_neato_utility", and calls run() on it, passing the
-//    passing first the function, last the FunctionTest instance, AND in the
-//    middle, most importantly a TestArguments instance that contains
-//
-//      (43 : Int, someValue : Value, other_fun : Function)
-//
-// 4) myNeatoUtilityTest calls takeUInt(), takeValue(), and takeFunction() on
-//    the test::Arguments instance.
-//      let count = arguments.takeInt()
-//      let target = arguments.takeValue()
-//      let callee = arguments.takeFunction()
-// 5) myNeatoUtilityTest calls myNeatoUtility, passing these values along.
-//      myNeatoUtility(int: count, value: target, function: callee)
-// 6) myNeatoUtilityTest then dumps out the current function, which was modified
-//    in the process.
-//      print(function)
-// 7) The test file test/SILOptimizer/interesting_functionality_unit.sil matches
-// the
-//    expected contents of the modified function:
-//    // CHECK-LABEL: sil @f
-//    // CHECK-NOT:     function_ref @other_fun
-//
-//===----------------------------------------------------------------------===//
-
-import Basic
-import SIL
-import SILBridging
-import OptimizerBridging
-
-/// The primary interface to in-IR tests.
-struct FunctionTest {
-  let name: String
-  let invocation: FunctionTestInvocation
-
-  public init(_ name: String, invocation: @escaping FunctionTestInvocation) {
-    self.name = name
-    self.invocation = invocation
-  }
-}
-
-/// The type of the closure passed to a FunctionTest.
-typealias FunctionTestInvocation = @convention(thin) (Function, TestArguments, FunctionPassContext) -> ()
-
-/// Wraps the arguments specified in the specify_test instruction.
-public struct TestArguments {
-  public var bridged: BridgedTestArguments
-  fileprivate init(bridged: BridgedTestArguments) {
-    self.bridged = bridged
-  }
-
-  public var hasUntaken: Bool { bridged.hasUntaken() }
-  public func takeString() -> StringRef { StringRef(bridged: bridged.takeString()) }
-  public func takeBool() -> Bool { bridged.takeBool() }
-  public func takeInt() -> Int { bridged.takeInt() }
-  public func takeOperand() -> Operand { Operand(bridged: bridged.takeOperand()) }
-  public func takeValue() -> Value { bridged.takeValue().value }
-  public func takeInstruction() -> Instruction { bridged.takeInstruction().instruction }
-  public func takeArgument() -> Argument { bridged.takeArgument().argument }
-  public func takeBlock() -> BasicBlock { bridged.takeBlock().block }
-  public func takeFunction() -> Function { bridged.takeFunction().function }
-}
-
-extension BridgedTestArguments {
-  public var native: TestArguments { TestArguments(bridged: self) }
-}
-
-/// Registration of each test in the SIL module.
-public func registerOptimizerTests() {
-  // Register each test.
-  registerFunctionTests(
-    getAccessBaseTest,
-    addressOwnershipLiveRangeTest,
-    argumentConventionsTest,
-    borrowIntroducersTest,
-    enclosingValuesTest,
-    forwardingDefUseTest,
-    forwardingUseDefTest,
-    interiorLivenessTest,
-    lifetimeDependenceScopeTest,
-    lifetimeDependenceUseTest,
-    linearLivenessTest,
-    parseTestSpecificationTest,
-    variableIntroducerTest,
-    gatherCallSitesTest,
-    specializedFunctionSignatureAndBodyTest,
-    rewrittenCallerBodyTest
-  )
-
-  // Finally register the thunk they all call through.
-  registerFunctionTestThunk(functionTestThunk)
-}
-
-private func registerFunctionTests(_ tests: FunctionTest...) {
-  tests.forEach { registerFunctionTest($0) }
-}
-
-private func registerFunctionTest(_ test: FunctionTest) {
-  test.name._withBridgedStringRef { ref in
-    registerFunctionTest(ref, castToOpaquePointer(fromInvocation: test.invocation))
-  }
-}
-
-/// The function called by the swift::test::FunctionTest which invokes the
-/// actual test function.
-///
-/// This function is necessary because tests need to be written in terms of
-/// native Swift types (Function, TestArguments, BridgedPassContext)
-/// rather than their bridged variants, but such a function isn't representable
-/// in C++.  This thunk unwraps the bridged types and invokes the real
-/// function.
-private func functionTestThunk(
-  _ erasedInvocation: UnsafeMutableRawPointer,
-  _ function: BridgedFunction, 
-  _ arguments: BridgedTestArguments, 
-  _ passInvocation: BridgedSwiftPassInvocation) {
-  let invocation = castToInvocation(fromOpaquePointer: erasedInvocation)
-  let context = FunctionPassContext(_bridged: BridgedPassContext(invocation: passInvocation.invocation))
-  invocation(function.function, arguments.native, context)
-}
-
-/// Bitcast a thin test closure to void *.
-///
-/// Needed so that the closure can be represented in C++ for storage in the test
-/// registry.
-private func castToOpaquePointer(fromInvocation invocation: FunctionTestInvocation) -> UnsafeMutableRawPointer {
-  return unsafeBitCast(invocation, to: UnsafeMutableRawPointer.self)
-}
-
-/// Bitcast a void * to a thin test closure.
-///
-/// Needed so that the closure stored in the C++ test registry can be invoked
-/// via the functionTestThunk.
-private func castToInvocation(fromOpaquePointer erasedInvocation: UnsafeMutableRawPointer) -> FunctionTestInvocation {
-  return unsafeBitCast(erasedInvocation, to: FunctionTestInvocation.self)
-}
-
-// Arguments:
-// - string: list of characters, each of which specifies subsequent arguments
-//           - A: (block) argument
-//           - F: function
-//           - B: block
-//           - I: instruction
-//           - V: value
-//           - O: operand
-//           - b: boolean
-//           - u: unsigned
-//           - s: string
-// - ...
-// - an argument of the type specified in the initial string
-// - ...
-// Dumps:
-// - for each argument (after the initial string)
-//   - its type
-//   - something to identify the instance (mostly this means calling dump)
-let parseTestSpecificationTest = 
-FunctionTest("test_specification_parsing") { function, arguments, context in 
-  let expectedFields = arguments.takeString()
-  for expectedField in expectedFields.string {
-    switch expectedField {
-    case "A":
-      let argument = arguments.takeArgument()
-      print("argument:\n\(argument)")
-    case "F":
-      let function = arguments.takeFunction()
-      print("function: \(function.name)")
-    case "B":
-      let block = arguments.takeBlock()
-      print("block:\n\(block)")
-    case "I":
-      let instruction = arguments.takeInstruction()
-      print("instruction: \(instruction)")
-    case "V":
-      let value = arguments.takeValue()
-      print("value: \(value)")
-    case "O":
-      let operand = arguments.takeOperand()
-      print("operand: \(operand)")
-    case "u":
-      let u = arguments.takeInt()
-      print("uint: \(u)")
-    case "b":
-      let b = arguments.takeBool()
-      print("bool: \(b)")
-    case "s":
-      let s = arguments.takeString()
-      print("string: \(s)")
-    default:
-      fatalError("unknown field type was expected?!");
-    }
-  }
-}
diff --git a/SwiftCompilerSources/Sources/SIL/ASTExtensions.swift b/SwiftCompilerSources/Sources/SIL/ASTExtensions.swift
index f7aa212bfe8a2..f02ab08bef4a8 100644
--- a/SwiftCompilerSources/Sources/SIL/ASTExtensions.swift
+++ b/SwiftCompilerSources/Sources/SIL/ASTExtensions.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -31,6 +31,11 @@ extension CanonicalType {
   public var silType: Type? {
     BridgedType.createSILType(bridged).typeOrNil
   }
+
+  public func getBoxFields(in function: Function) -> BoxFieldsArray {
+    precondition(isBox)
+    return BoxFieldsArray(boxType: self, function: function)
+  }
 }
 
 extension Decl {
@@ -50,7 +55,42 @@ extension ClassDecl {
 }
 
 extension SubstitutionMap {
-  public func getMethodSubstitutions(for method: Function) -> SubstitutionMap {
-    return SubstitutionMap(bridged: method.bridged.getMethodSubstitutions(bridged))
+  /// Returns the substitutions to specialize a method.
+  ///
+  /// If this is a default witness methods (`selfType` != nil) it has generic self type. In this case
+  /// the generic self parameter is at depth 0 and the actual generic parameters of the substitution map
+  /// are at depth + 1, e.g:
+  /// ```
+  ///     @convention(witness_method: P) <τ_0_0><τ_1_0 where τ_0_0 : GenClass<τ_1_0>.T>
+  ///                                       ^      ^
+  ///                                    self      params of substitution map at depth + 1
+  /// ```
+  public func getMethodSubstitutions(for method: Function, selfType: CanonicalType? = nil) -> SubstitutionMap {
+    return SubstitutionMap(bridged: method.bridged.getMethodSubstitutions(bridged,
+                                                                          selfType?.bridged ?? BridgedCanType()))
+  }
+}
+
+extension Conformance {
+  /// Returns true if the conformance is not isolated or if its isolation matches
+  /// the isolation in `function`.
+  public func matchesActorIsolation(in function: Function) -> Bool {
+    return function.bridged.conformanceMatchesActorIsolation(bridged)
+  }
+}
+
+extension DiagnosticEngine {
+  public func diagnose(_ id: DiagID, _ args: DiagnosticArgument..., at location: Location) {
+    diagnose(id, args, at: location.getSourceLocation(diagnosticEngine: self))
+  }
+
+  public func diagnose(_ id: DiagID, _ args: [DiagnosticArgument], at location: Location) {
+    diagnose(id, args, at: location.getSourceLocation(diagnosticEngine: self))
+  }
+}
+
+extension Diagnostic where SourceLocation == Location {
+  public init(_ id: DiagID, _ arguments: DiagnosticArgument..., at location: Location) {
+    self.init(id, arguments, at: location)
   }
 }
diff --git a/SwiftCompilerSources/Sources/SIL/ApplySite.swift b/SwiftCompilerSources/Sources/SIL/ApplySite.swift
index a8bf3a07fb3bf..7f0187819e097 100644
--- a/SwiftCompilerSources/Sources/SIL/ApplySite.swift
+++ b/SwiftCompilerSources/Sources/SIL/ApplySite.swift
@@ -72,6 +72,7 @@ public struct ApplyOperandConventions : Collection {
       calleeArgumentIndex(ofOperandIndex: operandIndex)!]
   }
 
+  // If the specified parameter is a dependency target, return its dependency sources.
   public subscript(parameterDependencies operandIndex: Int)
     -> FunctionConvention.LifetimeDependencies? {
     return calleeArgumentConventions[parameterDependencies:
@@ -229,6 +230,13 @@ extension ApplySite {
     functionConvention.resultDependencies != nil
   }
 
+  public func isAddressable(operand: Operand) -> Bool {
+    if let dep = resultDependence(on: operand) {
+      return dep.isAddressable(for: operand.value)
+    }
+    return false
+  }
+
   public var hasLifetimeDependence: Bool {
     functionConvention.hasLifetimeDependencies()
   }
@@ -270,18 +278,35 @@ extension ApplySite {
     return argumentOperands[callerArgIdx]
   }
 
-  /// Returns the argument index of an operand.
+  /// Returns the argument of `operand` in a callee function.
   ///
-  /// Returns nil if 'operand' is not an argument operand. This is the case if
+  /// Returns nil if `operand` is not an argument operand. This is the case if
   /// it's the callee function operand.
+  public func calleeArgument(of operand: Operand, in callee: Function) -> FunctionArgument? {
+    if let argIdx = calleeArgumentIndex(of: operand) {
+      return callee.arguments[argIdx]
+    }
+    return nil
+  }
+
+  /// Returns the argument index of an operand.
   ///
-  /// Warning: the returned integer can be misused as an index into
-  /// the wrong collection. Replace uses of this API with safer APIs.
+  /// Returns nil if `operand` is not an argument operand. This is the case if
+  /// it's the callee function operand.
   ///
-  /// TODO: delete this API and rewrite the users. 
+  /// Warning: the returned integer can be misused as an index into the wrong collection.
+  /// Use `calleeArgument(of:,in:)` if possible.
   public func calleeArgumentIndex(of operand: Operand) -> Int? {
     operandConventions.calleeArgumentIndex(of: operand)
   }
+
+  public var hasGuaranteedResult: Bool {
+    functionConvention.hasGuaranteedResult
+  }
+
+  public var hasGuaranteedAddressResult: Bool {
+    functionConvention.hasGuaranteedAddressResult
+  }
 }
 
 extension ApplySite {
diff --git a/SwiftCompilerSources/Sources/SIL/Argument.swift b/SwiftCompilerSources/Sources/SIL/Argument.swift
index 26c6bed560e4d..febd27f9af5dc 100644
--- a/SwiftCompilerSources/Sources/SIL/Argument.swift
+++ b/SwiftCompilerSources/Sources/SIL/Argument.swift
@@ -32,11 +32,23 @@ public class Argument : Value, Hashable {
 
   public var isReborrow: Bool { bridged.isReborrow() }
 
+  public func set(reborrow: Bool, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.setReborrow(reborrow)
+  }
+
   public var isLexical: Bool { false }
 
-  public var varDecl: VarDecl? { bridged.getVarDecl().getAs(VarDecl.self) }
+  public var decl: ValueDecl? { bridged.getDecl().getAs(ValueDecl.self) }
+
+  public func findVarDecl() -> VarDecl? {
+    if let varDecl = decl as? VarDecl {
+      return varDecl
+    }
+    return findVarDeclFromDebugUsers()
+  }
 
-  public var sourceLoc: SourceLoc? { varDecl?.nameLoc }
+  public var sourceLoc: SourceLoc? { findVarDecl()?.nameLoc }
 
   public static func ==(lhs: Argument, rhs: Argument) -> Bool {
     lhs === rhs
@@ -56,6 +68,10 @@ final public class FunctionArgument : Argument {
     bridged.FunctionArgument_isLexical()
   }
 
+  public var isClosureCapture: Bool {
+    bridged.FunctionArgument_isClosureCapture()
+  }
+
   public var isSelf: Bool {
     parentFunction.argumentConventions.selfIndex == index
   }
@@ -78,7 +94,8 @@ final public class FunctionArgument : Argument {
   /// 2. lifetimeAnnotation
   /// 3. closureCapture
   /// 4. parameterPack
-  public func copyFlags(from arg: FunctionArgument) {
+  public func copyFlags(from arg: FunctionArgument, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
     bridged.copyFlags(arg.bridged)
   }
 }
@@ -153,7 +170,7 @@ public struct Phi {
   }
 
   public var incomingValues: LazyMapSequence<LazyMapSequence<PredecessorList, Operand>, Value> {
-    incomingOperands.lazy.map { $0.value }
+    incomingOperands.values
   }
 
   public var isReborrow: Bool { value.isReborrow }
@@ -192,6 +209,22 @@ public struct Phi {
   }
 }
 
+extension Phi {
+  /// Return true of this phi is directly returned with no side effects between the phi and the return.
+  public var isReturnValue: Bool {
+    if let singleUse = value.uses.singleUse, let ret = singleUse.instruction as? ReturnInst,
+       ret.parentBlock == successor {
+      for inst in successor.instructions {
+        if inst.mayHaveSideEffects {
+          return false
+        }
+      }
+      return true
+    }
+    return false
+  }
+}
+
 extension Operand {
   public var forwardingBorrowedFromUser: BorrowedFromInst? {
     if let bfi = instruction as? BorrowedFromInst, index == 0 {
@@ -260,7 +293,7 @@ public struct ArgumentConventions : Collection, CustomStringConvertible {
     if let paramIdx = parameterIndex(for: argumentIndex) {
       return convention.parameters[paramIdx].convention
     }
-    let resultInfo = convention.indirectSILResults[argumentIndex]
+    let resultInfo = convention.indirectSILResult(at: argumentIndex)
     return ArgumentConvention(result: resultInfo.convention)
   }
 
@@ -268,7 +301,7 @@ public struct ArgumentConventions : Collection, CustomStringConvertible {
     if parameterIndex(for: argumentIndex) != nil {
       return nil
     }
-    return convention.indirectSILResults[argumentIndex]
+    return convention.indirectSILResult(at: argumentIndex)
   }
 
   public subscript(parameter argumentIndex: Int) -> ParameterInfo? {
@@ -455,6 +488,8 @@ public enum ArgumentConvention : CustomStringConvertible {
       self = .directUnowned
     case .pack:
       self = .packOut
+    case .guaranteed, .guaranteedAddress:
+      fatalError("Result conventions @guaranteed and @guaranteed_addr are always returned directly")
     }
   }
 
@@ -591,19 +626,6 @@ public enum ArgumentConvention : CustomStringConvertible {
   }
 }
 
-extension BeginAccessInst.AccessKind {
-  public func isCompatible(with convention: ArgumentConvention) -> Bool {
-    switch self {
-    case .`init`, .deinit:
-      return false
-    case .read:
-      return convention.isIndirectIn
-    case .modify:
-      return convention.isInout
-    }
-  }
-}
-
 // Bridging utilities
 
 extension BridgedArgument {
diff --git a/SwiftCompilerSources/Sources/SIL/BasicBlock.swift b/SwiftCompilerSources/Sources/SIL/BasicBlock.swift
index 3d9613c085adc..c543559c24489 100644
--- a/SwiftCompilerSources/Sources/SIL/BasicBlock.swift
+++ b/SwiftCompilerSources/Sources/SIL/BasicBlock.swift
@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-import Basic
+import AST
 import SILBridging
 
 @_semantics("arc.immortal")
@@ -25,8 +25,69 @@ final public class BasicBlock : CustomStringConvertible, HasShortDescription, Ha
   }
   public var shortDescription: String { name }
 
+  /// The index of the basic block in its function.
+  /// This has O(n) complexity. Only use it for debugging
+  public var index: Int {
+    for (idx, block) in parentFunction.blocks.enumerated() {
+      if block == self { return idx }
+    }
+    fatalError()
+  }
+
+  public var name: String { "bb\(index)" }
+
+  public static func == (lhs: BasicBlock, rhs: BasicBlock) -> Bool { lhs === rhs }
+
+  public func hash(into hasher: inout Hasher) {
+    hasher.combine(ObjectIdentifier(self))
+  }
+
+  public var bridged: BridgedBasicBlock { BridgedBasicBlock(SwiftObject(self)) }
+
+  //===----------------------------------------------------------------------===//
+  //                                  Arguments
+  //===----------------------------------------------------------------------===//
+
   public var arguments: ArgumentArray { ArgumentArray(block: self) }
 
+  public func addArgument(type: Type, ownership: Ownership, _ context: some MutatingContext) -> Argument {
+    context.notifyInstructionsChanged()
+    return bridged.addBlockArgument(type.bridged, ownership._bridged).argument
+  }
+
+  public func addFunctionArgument(type: Type, _ context: some MutatingContext) -> FunctionArgument {
+    context.notifyInstructionsChanged()
+    return bridged.addFunctionArgument(type.bridged).argument as! FunctionArgument
+  }
+
+  public func insertFunctionArgument(atPosition: Int, type: Type, ownership: Ownership, decl: ValueDecl? = nil,
+                              _ context: some MutatingContext) -> FunctionArgument
+  {
+    context.notifyInstructionsChanged()
+    return bridged.insertFunctionArgument(atPosition, type.bridged, ownership._bridged,
+                                          (decl as Decl?).bridged).argument as! FunctionArgument
+  }
+
+  public func eraseArgument(at index: Int, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.eraseArgument(index)
+  }
+
+  public func eraseAllArguments(_ context: some MutatingContext) {
+    // Arguments are stored in an array. We need to erase in reverse order to avoid quadratic complexity.
+    for argIdx in (0 ..< arguments.count).reversed() {
+      eraseArgument(at: argIdx, context)
+    }
+  }
+
+  public func moveAllArguments(to otherBlock: BasicBlock, _ context: some MutatingContext) {
+    bridged.moveArgumentsTo(otherBlock.bridged)
+  }
+
+  //===----------------------------------------------------------------------===//
+  //                               Instructions
+  //===----------------------------------------------------------------------===//
+
   public var instructions: InstructionList {
     InstructionList(first: bridged.getFirstInst().instruction)
   }
@@ -35,6 +96,22 @@ final public class BasicBlock : CustomStringConvertible, HasShortDescription, Ha
     bridged.getLastInst().instruction as! TermInst
   }
 
+  public func moveAllInstructions(toBeginOf otherBlock: BasicBlock, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    context.notifyBranchesChanged()
+    bridged.moveAllInstructionsToBegin(otherBlock.bridged)
+  }
+
+  public func moveAllInstructions(toEndOf otherBlock: BasicBlock, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    context.notifyBranchesChanged()
+    bridged.moveAllInstructionsToEnd(otherBlock.bridged)
+  }
+
+  //===----------------------------------------------------------------------===//
+  //                        predecessors and successors
+  //===----------------------------------------------------------------------===//
+
   public var successors: SuccessorArray { terminator.successors }
 
   public var predecessors: PredecessorList {
@@ -76,25 +153,14 @@ final public class BasicBlock : CustomStringConvertible, HasShortDescription, Ha
         return false
     }
   }
-
-  /// The index of the basic block in its function.
-  /// This has O(n) complexity. Only use it for debugging
-  public var index: Int {
-    for (idx, block) in parentFunction.blocks.enumerated() {
-      if block == self { return idx }
+  
+  public func isCriticalEdge(edgeIndex: Int) -> Bool {
+    if terminator.successors.count <= 1 {
+      return false
+    } else {
+      return !terminator.successors[edgeIndex].hasSinglePredecessor
     }
-    fatalError()
-  }
- 
-  public var name: String { "bb\(index)" }
-
-  public static func == (lhs: BasicBlock, rhs: BasicBlock) -> Bool { lhs === rhs }
-
-  public func hash(into hasher: inout Hasher) {
-    hasher.combine(ObjectIdentifier(self))
   }
-
-  public var bridged: BridgedBasicBlock { BridgedBasicBlock(SwiftObject(self)) }
 }
 
 /// The list of instructions in a BasicBlock.
diff --git a/SwiftCompilerSources/Sources/SIL/Builder.swift b/SwiftCompilerSources/Sources/SIL/Builder.swift
index fa4b3e1725e0d..a452695eca9b8 100644
--- a/SwiftCompilerSources/Sources/SIL/Builder.swift
+++ b/SwiftCompilerSources/Sources/SIL/Builder.swift
@@ -26,9 +26,90 @@ public struct Builder {
 
   public let insertionPoint: InsertionPoint
   let location: Location
-  private let notificationHandler: BridgedChangeNotificationHandler
+  private let notificationHandler: BridgedContext
   private let notifyNewInstruction: (Instruction) -> ()
 
+  /// Creates a builder which inserts _before_ `insPnt`, using a custom `location`.
+  public init(before insPnt: Instruction, location: Location, _ context: some MutatingContext) {
+    context.verifyIsTransforming(function: insPnt.parentFunction)
+    self.init(insertAt: .before(insPnt), location: location, context.notifyInstructionChanged, context._bridged)
+  }
+
+  /// Creates a builder which inserts before `insPnt`, using `insPnt`'s next
+  /// non-meta instruction's location.
+  /// This function should be used when moving code to an unknown insert point,
+  /// when we want to inherit the location of the closest non-meta instruction.
+  /// For replacing an existing meta instruction with another, use
+  /// ``Builder.init(replacing:_:)``.
+  public init(before insPnt: Instruction, _ context: some MutatingContext) {
+    context.verifyIsTransforming(function: insPnt.parentFunction)
+    self.init(insertAt: .before(insPnt), location: insPnt.location,
+              context.notifyInstructionChanged, context._bridged)
+  }
+
+  /// Creates a builder which inserts _before_ `insPnt`, using the exact location of `insPnt`,
+  /// for the purpose of replacing that meta instruction with an equivalent instruction.
+  /// This function does not delete `insPnt`.
+  public init(replacing insPnt: MetaInstruction, _ context: some MutatingContext) {
+    context.verifyIsTransforming(function: insPnt.parentFunction)
+    self.init(insertAt: .before(insPnt), location: insPnt.location, context.notifyInstructionChanged, context._bridged)
+  }
+
+  /// Creates a builder which inserts _after_ `insPnt`, using a custom `location`.
+  ///
+  /// TODO: this is usually incorrect for terminator instructions. Instead use
+  /// `Builder.insert(after:location:_:insertFunc)` from OptUtils.swift. Rename this to afterNonTerminator.
+  public init(after insPnt: Instruction, location: Location, _ context: some MutatingContext) {
+    context.verifyIsTransforming(function: insPnt.parentFunction)
+    guard let nextInst = insPnt.next else {
+      fatalError("cannot insert an instruction after a block terminator.")
+    }
+    self.init(insertAt: .before(nextInst), location: location, context.notifyInstructionChanged, context._bridged)
+  }
+
+  /// Creates a builder which inserts _after_ `insPnt`, using `insPnt`'s next
+  /// non-meta instruction's location.
+  ///
+  /// TODO: this is incorrect for terminator instructions. Instead use `Builder.insert(after:location:_:insertFunc)`
+  /// from OptUtils.swift. Rename this to afterNonTerminator.
+  public init(after insPnt: Instruction, _ context: some MutatingContext) {
+    self.init(after: insPnt, location: insPnt.location, context)
+  }
+
+  /// Creates a builder which inserts at the end of `block`, using a custom `location`.
+  public init(atEndOf block: BasicBlock, location: Location, _ context: some MutatingContext) {
+    context.verifyIsTransforming(function: block.parentFunction)
+    self.init(insertAt: .atEndOf(block), location: location, context.notifyInstructionChanged, context._bridged)
+  }
+
+  /// Creates a builder which inserts at the begin of `block`, using a custom `location`.
+  public init(atBeginOf block: BasicBlock, location: Location, _ context: some MutatingContext) {
+    context.verifyIsTransforming(function: block.parentFunction)
+    let firstInst = block.instructions.first!
+    self.init(insertAt: .before(firstInst), location: location, context.notifyInstructionChanged, context._bridged)
+  }
+
+  /// Creates a builder which inserts at the begin of `block`, using the location of the first
+  /// non-meta instruction of `block`.
+  public init(atBeginOf block: BasicBlock, _ context: some MutatingContext) {
+    context.verifyIsTransforming(function: block.parentFunction)
+    let firstInst = block.instructions.first!
+    self.init(insertAt: .before(firstInst),
+              location: firstInst.location, context.notifyInstructionChanged, context._bridged)
+  }
+
+  /// Creates a builder which inserts instructions into an empty function, using the location of the function itself.
+  public init(atStartOf function: Function, _ context: some MutatingContext) {
+    context.verifyIsTransforming(function: function)
+    self.init(insertAt: .atStartOf(function), location: function.location,
+              context.notifyInstructionChanged, context._bridged)
+  }
+
+  public init(staticInitializerOf global: GlobalVariable, _ context: some MutatingContext) {
+    self.init(insertAt: .staticInitializer(global),
+              location: Location.artificialUnreachableLocation, { _ in }, context._bridged)
+  }
+
   /// Return 'nil' when inserting at the start of a function or in a global initializer.
   public var insertionBlock: BasicBlock? {
     switch insertionPoint {
@@ -59,20 +140,20 @@ public struct Builder {
   }
 
   private func notifyNew<I: Instruction>(_ instruction: I) -> I {
-    notificationHandler.notifyChanges(.instructionsChanged)
+    notificationHandler.notifyChanges(.Instructions)
     if instruction is FullApplySite {
-      notificationHandler.notifyChanges(.callsChanged)
+      notificationHandler.notifyChanges(.Calls)
     }
     if instruction is TermInst {
-      notificationHandler.notifyChanges(.branchesChanged)
+      notificationHandler.notifyChanges(.Branches)
     }
     notifyNewInstruction(instruction)
     return instruction
   }
 
-  public init(insertAt: InsertionPoint, location: Location,
+  private init(insertAt: InsertionPoint, location: Location,
               _ notifyNewInstruction: @escaping (Instruction) -> (),
-              _ notificationHandler: BridgedChangeNotificationHandler) {
+              _ notificationHandler: BridgedContext) {
     self.insertionPoint = insertAt
     self.location = location;
     self.notifyNewInstruction = notifyNewInstruction
@@ -109,11 +190,40 @@ public struct Builder {
     }
   }
 
-  public func createIntegerLiteral(_ value: Int, type: Type) -> IntegerLiteralInst {
-    let literal = bridged.createIntegerLiteral(type.bridged, value)
+  /// Creates a integer literal instruction with the given integer value and
+  /// type. If an extension is necessary, the value is extended in accordance
+  /// with the signedness of `Value`.
+  public func createIntegerLiteral<Value: FixedWidthInteger>(
+    _ value: Value,
+    type: Type
+  ) -> IntegerLiteralInst {
+    precondition(
+      Value.bitWidth <= Int.bitWidth,
+      "Cannot fit \(Value.bitWidth)-bit integer into \(Int.bitWidth)-bit 'Swift.Int'"
+    )
+    // Extend the value based on its signedness to the bit width of `Int` and
+    // reinterpret it as an `Int`.
+    let extendedValue: Int =
+      if Value.isSigned {
+        Int(value)
+      } else {
+        // NB: This initializer is effectively a generic equivalent
+        // of `Int(bitPattern:)`
+        Int(truncatingIfNeeded: value)
+      }
+
+    let literal = bridged.createIntegerLiteral(type.bridged, extendedValue, Value.isSigned)
     return notifyNew(literal.getAs(IntegerLiteralInst.self))
   }
-    
+
+  /// Creates a `Builtin.Int1` integer literal instruction with a value
+  /// corresponding to the given Boolean.
+  public func createBoolLiteral(_ value: Bool) -> IntegerLiteralInst {
+    let boolType = notificationHandler.getBuiltinIntegerType(1).type
+    let integerValue: UInt = value ? 1 : 0
+    return createIntegerLiteral(integerValue, type: boolType)
+  }
+
   public func createAllocRef(_ type: Type, isObjC: Bool = false, canAllocOnStack: Bool = false, isBare: Bool = false,
                              tailAllocatedTypes: TypeArray, tailAllocatedCounts: [Value]) -> AllocRefInst {
     return tailAllocatedCounts.withBridgedValues { countsRef in
@@ -122,12 +232,20 @@ public struct Builder {
     }
   }
 
-  public func createAllocStack(_ type: Type, hasDynamicLifetime: Bool = false,
+  public func createAllocStack(_ type: Type,
+                               debugVariable: DebugVariableInstruction.DebugVariable? = nil,
+                               hasDynamicLifetime: Bool = false,
                                isLexical: Bool = false, isFromVarDecl: Bool = false,
                                usesMoveableValueDebugInfo: Bool = false) -> AllocStackInst {
-    let dr = bridged.createAllocStack(type.bridged, hasDynamicLifetime, isLexical,
-                                      isFromVarDecl, usesMoveableValueDebugInfo)
-    return notifyNew(dr.getAs(AllocStackInst.self))
+    let allocStack: BridgedInstruction
+    if let debugVariable = debugVariable {
+      allocStack = bridged.createAllocStack(type.bridged, debugVariable, hasDynamicLifetime, isLexical,
+                                            isFromVarDecl, usesMoveableValueDebugInfo)
+    } else {
+      allocStack = bridged.createAllocStack(type.bridged, hasDynamicLifetime, isLexical,
+                                            isFromVarDecl, usesMoveableValueDebugInfo)
+    }
+    return notifyNew(allocStack.getAs(AllocStackInst.self))
   }
 
   @discardableResult
@@ -171,6 +289,11 @@ public struct Builder {
     return notifyNew(cast.getAs(UncheckedAddrCastInst.self))
   }
 
+  public func createUncheckedValueCast(from value: Value, to type: Type) -> UncheckedValueCastInst {
+    let cast = bridged.createUncheckedValueCast(value.bridged, type.bridged)
+    return notifyNew(cast.getAs(UncheckedValueCastInst.self))
+  }
+
   public func createUpcast(from value: Value, to type: Type) -> UpcastInst {
     let cast = bridged.createUpcast(value.bridged, type.bridged)
     return notifyNew(cast.getAs(UpcastInst.self))
@@ -180,7 +303,7 @@ public struct Builder {
   public func createCheckedCastAddrBranch(
     source: Value, sourceFormalType: CanonicalType,
     destination: Value, targetFormalType: CanonicalType,
-    isolatedConformances: CastingIsolatedConformances,
+    options: CheckedCastInstOptions,
     consumptionKind: CheckedCastAddrBranchInst.CastConsumptionKind,
     successBlock: BasicBlock,
     failureBlock: BasicBlock
@@ -195,7 +318,7 @@ public struct Builder {
 
     let cast = bridged.createCheckedCastAddrBranch(source.bridged, sourceFormalType.bridged,
                                                    destination.bridged, targetFormalType.bridged,
-                                                   isolatedConformances.bridged,
+                                                   options.bridged,
                                                    bridgedConsumption,
                                                    successBlock.bridged, failureBlock.bridged)
     return notifyNew(cast.getAs(CheckedCastAddrBranchInst.self))
@@ -203,18 +326,24 @@ public struct Builder {
 
   @discardableResult
   public func createUnconditionalCheckedCastAddr(
-    isolatedConformances: CastingIsolatedConformances,
+    options: CheckedCastInstOptions,
     source: Value, sourceFormalType: CanonicalType,
     destination: Value, targetFormalType: CanonicalType
   ) -> UnconditionalCheckedCastAddrInst {
     let cast = bridged.createUnconditionalCheckedCastAddr(
-        isolatedConformances.bridged, source.bridged,
-        sourceFormalType.bridged,
+        options.bridged, source.bridged, sourceFormalType.bridged,
         destination.bridged, targetFormalType.bridged
     )
     return notifyNew(cast.getAs(UnconditionalCheckedCastAddrInst.self))
   }
 
+  public func createUncheckedOwnershipConversion(
+    operand: Value, resultOwnership: Ownership
+  ) -> UncheckedOwnershipConversionInst {
+    let uoc = bridged.createUncheckedOwnershipConversion(operand.bridged, resultOwnership._bridged)
+    return notifyNew(uoc.getAs(UncheckedOwnershipConversionInst.self))
+  }
+
   public func createLoad(fromAddress: Value, ownership: LoadInst.LoadOwnership) -> LoadInst {
     let load = bridged.createLoad(fromAddress.bridged, ownership.rawValue)
     return notifyNew(load.getAs(LoadInst.self))
@@ -368,6 +497,20 @@ public struct Builder {
     return notifyNew(apply.getAs(TryApplyInst.self))
   }
   
+  public func createBeginApply(function: Value,
+                               _ substitutionMap: SubstitutionMap,
+                               arguments: [Value],
+                               isNonThrowing: Bool = false,
+                               isNonAsync: Bool = false,
+                               specializationInfo: ApplyInst.SpecializationInfo = ApplyInst.SpecializationInfo()
+  ) -> BeginApplyInst {
+    let apply = arguments.withBridgedValues { valuesRef in
+      bridged.createBeginApply(function.bridged, substitutionMap.bridged, valuesRef,
+                               isNonThrowing, isNonAsync, specializationInfo)
+    }
+    return notifyNew(apply.getAs(BeginApplyInst.self))
+  }
+  
   public func createWitnessMethod(lookupType: CanonicalType,
                                   conformance: Conformance,
                                   member: DeclRef,
@@ -458,6 +601,12 @@ public struct Builder {
     }
   }
 
+  @discardableResult
+  public func createCondBranch(condition: Value, trueBlock: BasicBlock, falseBlock: BasicBlock) -> CondBranchInst {
+    let condBr = bridged.createCondBranch(condition.bridged, trueBlock.bridged, falseBlock.bridged)
+    return notifyNew(condBr.getAs(CondBranchInst.self))
+  }
+
   @discardableResult
   public func createUnreachable() -> UnreachableInst {
     let ui = bridged.createUnreachable()
@@ -480,6 +629,10 @@ public struct Builder {
     return notifyNew(vectorInst.getAs(VectorInst.self))
   }
 
+  public func createVectorBaseAddr(vector: Value) -> VectorBaseAddrInst {
+    return notifyNew(bridged.createVectorBaseAddr(vector.bridged).getAs(VectorBaseAddrInst.self))
+  }
+
   public func createGlobalAddr(global: GlobalVariable, dependencyToken: Value?) -> GlobalAddrInst {
     return notifyNew(bridged.createGlobalAddr(global.bridged, dependencyToken.bridged).getAs(GlobalAddrInst.self))
   }
@@ -526,6 +679,10 @@ public struct Builder {
     return notifyNew(bridged.createDestructureTuple(tuple.bridged).getAs(DestructureTupleInst.self))
   }
 
+  public func createProjectBox(box: Value, fieldIndex: Int) -> ProjectBoxInst {
+    return notifyNew(bridged.createProjectBox(box.bridged, fieldIndex).getAs(ProjectBoxInst.self))
+  }
+
   @discardableResult
   public func createStore(source: Value, destination: Value, ownership: StoreInst.StoreOwnership) -> StoreInst {
     let store = bridged.createStore(source.bridged, destination.bridged, ownership.rawValue)
@@ -575,6 +732,12 @@ public struct Builder {
     return notifyNew(endMutation.getAs(EndCOWMutationInst.self))
   }
 
+  @discardableResult
+  public func createEndCOWMutationAddr(address: Value) -> EndCOWMutationAddrInst {
+    let endMutation = bridged.createEndCOWMutationAddr(address.bridged)
+    return notifyNew(endMutation.getAs(EndCOWMutationAddrInst.self))
+  }
+
   public func createMarkDependence(value: Value, base: Value, kind: MarkDependenceKind) -> MarkDependenceInst {
     let markDependence = bridged.createMarkDependence(value.bridged, base.bridged,
                                                       BridgedInstruction.MarkDependenceKind(rawValue: kind.rawValue)!)
@@ -587,6 +750,18 @@ public struct Builder {
     return notifyNew(markDependence.getAs(MarkDependenceAddrInst.self))
   }
     
+  public func createMarkUninitialized(value: Value, kind: MarkUninitializedInst.Kind) -> MarkUninitializedInst {
+    let mu = bridged.createMarkUninitialized(value.bridged, kind.rawValue)
+    return notifyNew(mu.getAs(MarkUninitializedInst.self))
+  }
+
+  public func createMarkUnresolvedNonCopyableValue(value: Value,
+                                                   checkKind: MarkUnresolvedNonCopyableValueInst.CheckKind,
+                                                   isStrict: Bool) -> MarkUnresolvedNonCopyableValueInst {
+    let mu = bridged.createMarkUnresolvedNonCopyableValue(value.bridged, checkKind.rawValue, isStrict)
+    return notifyNew(mu.getAs(MarkUnresolvedNonCopyableValueInst.self))
+  }
+
   @discardableResult
   public func createEndAccess(beginAccess: BeginAccessInst) -> EndAccessInst {
       let endAccess = bridged.createEndAccess(beginAccess.bridged)
@@ -615,3 +790,26 @@ public struct Builder {
     return notifyNew(convertFunction.getAs(ConvertEscapeToNoEscapeInst.self))
   }
 }
+
+
+//===----------------------------------------------------------------------===//
+//                                  Utilities
+//===----------------------------------------------------------------------===//
+
+extension Builder {
+  public func emitDestroy(of value: Value) {
+    if value.type.isTrivial(in: value.parentFunction) {
+      return
+    }
+    if value.type.isAddress {
+      return
+    }
+    if value.parentFunction.hasOwnership {
+      createDestroyValue(operand: value)
+    } else if value.type.isClass {
+      createStrongRelease(operand: value)
+    } else {
+      createReleaseValue(operand: value)
+    }
+  }
+}
diff --git a/SwiftCompilerSources/Sources/SIL/CMakeLists.txt b/SwiftCompilerSources/Sources/SIL/CMakeLists.txt
index 12cf7737028c6..8d4c2ac9275ac 100644
--- a/SwiftCompilerSources/Sources/SIL/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/SIL/CMakeLists.txt
@@ -17,6 +17,7 @@ add_swift_compiler_module(SIL
     BasicBlock.swift
     Builder.swift
     ConstExpressionEvaluator.swift
+    Context.swift
     DeclRef.swift
     Effects.swift
     ForwardingInstruction.swift
@@ -34,5 +35,6 @@ add_swift_compiler_module(SIL
     VTable.swift
     WitnessTable.swift)
 
+add_subdirectory(DataStructures)
 add_subdirectory(Utilities)
 
diff --git a/SwiftCompilerSources/Sources/SIL/Context.swift b/SwiftCompilerSources/Sources/SIL/Context.swift
new file mode 100644
index 0000000000000..e462904ade445
--- /dev/null
+++ b/SwiftCompilerSources/Sources/SIL/Context.swift
@@ -0,0 +1,210 @@
+//===--- Context.swift - defines the context protocols --------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SILBridging
+import AST
+
+public protocol Context {
+  var _bridged: BridgedContext { get }
+}
+
+/// A context which allows mutation of a function's SIL.
+public protocol MutatingContext : Context {
+  // Called by all instruction mutations, including inserted new instructions.
+  var notifyInstructionChanged: (Instruction) -> () { get }
+}
+
+/// Common funcationality of all Contexts.
+extension Context {
+  public var silStage: SILStage {
+    switch _bridged.getSILStage() {
+      case .Raw:       return .raw
+      case .Canonical: return .canonical
+      case .Lowered:   return .lowered
+      default:         fatalError("unhandled SILStage case")
+    }
+  }
+
+  public var currentModuleContext: ModuleDecl {
+    _bridged.getCurrentModuleContext().getAs(ModuleDecl.self)
+  }
+
+  public var moduleIsSerialized: Bool { _bridged.moduleIsSerialized() }
+
+  public var moduleHasLoweredAddresses: Bool { _bridged.moduleHasLoweredAddresses() }
+
+  public func lookupDeinit(ofNominal: NominalTypeDecl) -> Function? {
+    _bridged.lookUpNominalDeinitFunction(ofNominal.bridged).function
+  }
+
+  public func getBuiltinIntegerType(bitWidth: Int) -> Type { _bridged.getBuiltinIntegerType(bitWidth).type }
+
+  public func getTupleType(elements: [Type]) -> AST.`Type` {
+    let bridgedElements = elements.map { $0.bridged }
+    return bridgedElements.withBridgedArrayRef {
+      AST.`Type`(bridged: _bridged.getTupleType($0))
+    }
+  }
+
+  public var swiftArrayDecl: NominalTypeDecl {
+    _bridged.getSwiftArrayDecl().getAs(NominalTypeDecl.self)
+  }
+
+  public var swiftMutableSpan: NominalTypeDecl {
+    _bridged.getSwiftMutableSpanDecl().getAs(NominalTypeDecl.self)
+  }
+
+  public func lookupFunction(name: String) -> Function? {
+    name._withBridgedStringRef {
+      _bridged.lookupFunction($0).function
+    }
+  }
+
+  public func lookupWitnessTable(for conformance: Conformance) -> WitnessTable? {
+    return _bridged.lookupWitnessTable(conformance.bridged).witnessTable
+  }
+
+  public func lookupVTable(for classDecl: NominalTypeDecl) -> VTable? {
+    return _bridged.lookupVTable(classDecl.bridged).vTable
+  }
+
+  public func lookupSpecializedVTable(for classType: Type) -> VTable? {
+    return _bridged.lookupSpecializedVTable(classType.bridged).vTable
+  }
+
+  /// Looks up a function in the `Swift` module.
+  /// The `name` is the source name of the function and not the mangled name.
+  /// Returns nil if no such function or multiple matching functions are found.
+  public func lookupStdlibFunction(name: StaticString) -> Function? {
+    return name.withUTF8Buffer { (nameBuffer: UnsafeBufferPointer<UInt8>) in
+      let nameStr = BridgedStringRef(data: nameBuffer.baseAddress, count: nameBuffer.count)
+      return _bridged.lookupStdlibFunction(nameStr).function
+    }
+  }
+
+  public func getSpecializedConformance(of genericConformance: Conformance,
+                                        for type: AST.`Type`,
+                                        substitutions: SubstitutionMap) -> Conformance
+  {
+    let c = _bridged.getSpecializedConformance(genericConformance.bridged, type.bridged, substitutions.bridged)
+    return Conformance(bridged: c)
+  }
+}
+
+extension MutatingContext {
+  public func verifyIsTransforming(function: Function) {
+    precondition(_bridged.isTransforming(function.bridged), "pass modifies wrong function")
+  }
+
+  public func notifyInstructionsChanged() {
+    _bridged.notifyChanges(.Instructions)
+  }
+
+  public func notifyCallsChanged() {
+    _bridged.notifyChanges(.Calls)
+  }
+
+  public func notifyBranchesChanged() {
+    _bridged.notifyChanges(.Branches)
+  }
+
+  public func notifyEffectsChanged() {
+    _bridged.notifyChanges(.Effects)
+  }
+
+  public func createGlobalVariable(name: String, type: Type, linkage: Linkage, isLet: Bool, markedAsUsed: Bool) -> GlobalVariable {
+    let gv = name._withBridgedStringRef {
+      _bridged.createGlobalVariable($0, type.bridged, linkage.bridged, isLet,
+                                    markedAsUsed)
+    }
+    return gv.globalVar
+  }
+
+  /// Splits the basic block, which contains `inst`, before `inst` and returns the
+  /// new block.
+  ///
+  /// `inst` and all subsequent instructions are moved to the new block, while all
+  /// instructions _before_ `inst` remain in the original block.
+  public func splitBlock(before inst: Instruction) -> BasicBlock {
+    notifyBranchesChanged()
+    return _bridged.splitBlockBefore(inst.bridged).block
+  }
+
+  /// Splits the basic block, which contains `inst`, after `inst` and returns the
+  /// new block.
+  ///
+  /// All subsequent instructions after `inst` are moved to the new block, while `inst` and all
+  /// instructions _before_ `inst` remain in the original block.
+  public func splitBlock(after inst: Instruction) -> BasicBlock {
+    notifyBranchesChanged()
+    return _bridged.splitBlockAfter(inst.bridged).block
+  }
+
+  public func createBlock(after block: BasicBlock) -> BasicBlock {
+    notifyBranchesChanged()
+    return _bridged.createBlockAfter(block.bridged).block
+  }
+
+  /// Removes and deletes `instruction`.
+  /// If `salvageDebugInfo` is true, compensating `debug_value` instructions are inserted for certain
+  /// kind of instructions.
+  public func erase(instruction: Instruction, salvageDebugInfo: Bool = true) {
+    if !instruction.isInStaticInitializer {
+      verifyIsTransforming(function: instruction.parentFunction)
+    }
+    if instruction is FullApplySite {
+      notifyCallsChanged()
+    }
+    if instruction is TermInst {
+      notifyBranchesChanged()
+    }
+    notifyInstructionsChanged()
+
+    for operand in instruction.operands {
+      if let opInst = operand.value.definingInstruction {
+        notifyInstructionChanged(opInst)
+      }
+    }
+
+    _bridged.eraseInstruction(instruction.bridged, salvageDebugInfo)
+  }
+
+  public func erase(instructionIncludingAllUsers inst: Instruction) {
+    if inst.isDeleted {
+      return
+    }
+    for result in inst.results {
+      for use in result.uses {
+        erase(instructionIncludingAllUsers: use.instruction)
+      }
+    }
+    // We rely that after deleting the instruction its operands have no users.
+    // Therefore `salvageDebugInfo` must be turned off because we cannot insert debug_value instructions.
+    erase(instruction: inst, salvageDebugInfo: false)
+  }
+
+  public func erase<S: Sequence>(instructions: S) where S.Element: Instruction {
+    for inst in instructions {
+      erase(instruction: inst)
+    }
+  }
+
+  public func erase(instructionIncludingDebugUses inst: Instruction) {
+    precondition(inst.results.allSatisfy { $0.uses.ignoreDebugUses.isEmpty })
+    erase(instructionIncludingAllUsers: inst)
+  }
+
+  public func erase(block: BasicBlock) {
+    _bridged.eraseBlock(block.bridged)
+  }
+
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/DataStructures/BasicBlockRange.swift b/SwiftCompilerSources/Sources/SIL/DataStructures/BasicBlockRange.swift
similarity index 79%
rename from SwiftCompilerSources/Sources/Optimizer/DataStructures/BasicBlockRange.swift
rename to SwiftCompilerSources/Sources/SIL/DataStructures/BasicBlockRange.swift
index cc33b70c71ef5..140a746a41d6a 100644
--- a/SwiftCompilerSources/Sources/Optimizer/DataStructures/BasicBlockRange.swift
+++ b/SwiftCompilerSources/Sources/SIL/DataStructures/BasicBlockRange.swift
@@ -10,8 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-import SIL
-
 /// A range of basic blocks.
 ///
 /// The `BasicBlockRange` defines a range from a dominating "begin" block to one or more "end" blocks.
@@ -46,16 +44,16 @@ import SIL
 /// This type should be a move-only type, but unfortunately we don't have move-only
 /// types yet. Therefore it's needed to call `deinitialize()` explicitly to
 /// destruct this data structure, e.g. in a `defer {}` block.
-struct BasicBlockRange : CustomStringConvertible, NoReflectionChildren {
+public struct BasicBlockRange : CustomStringConvertible, NoReflectionChildren {
 
   /// The dominating begin block.
-  let begin: BasicBlock
+  public let begin: BasicBlock
 
   /// The inclusive range, i.e. the exclusive range plus the end blocks.
-  private(set) var inclusiveRange: Stack<BasicBlock>
-  
+  public private(set) var inclusiveRange: Stack<BasicBlock>
+
   /// The exclusive range, i.e. not containing the end blocks.
-  var range: LazyFilterSequence<Stack<BasicBlock>> {
+  public var range: LazyFilterSequence<Stack<BasicBlock>> {
     inclusiveRange.lazy.filter { contains($0) }
   }
 
@@ -66,7 +64,7 @@ struct BasicBlockRange : CustomStringConvertible, NoReflectionChildren {
   private var inExclusiveRange: BasicBlockSet
   private var worklist: BasicBlockWorklist
   
-  init(begin: BasicBlock, _ context: some Context) {
+  public init(begin: BasicBlock, _ context: some Context) {
     self.begin = begin
     self.inclusiveRange = Stack(context)
     self.inserted = Stack(context)
@@ -77,39 +75,48 @@ struct BasicBlockRange : CustomStringConvertible, NoReflectionChildren {
   }
 
   /// Insert a potential end block.
-  mutating func insert(_ block: BasicBlock) {
+  ///
+  /// Returns true if the begin-block is reached during backward propagation.
+  /// Usually this is not relevant, but InstructionRange needs this information.
+  @discardableResult
+  public mutating func insert(_ block: BasicBlock) -> Bool {
     if wasInserted.insert(block) {
       inserted.append(block)
     }
     worklist.pushIfNotVisited(block)
+    var visitedBeginBlock = false
     while let b = worklist.pop() {
       inclusiveRange.append(b)
       if b != begin {
         for pred in b.predecessors {
+          if pred == begin {
+            visitedBeginBlock = true
+          }
           worklist.pushIfNotVisited(pred)
           inExclusiveRange.insert(pred)
         }
       }
     }
+    return visitedBeginBlock
   }
 
   /// Insert a sequence of potential end blocks.
-  mutating func insert<S: Sequence>(contentsOf other: S) where S.Element == BasicBlock {
+  public mutating func insert<S: Sequence>(contentsOf other: S) where S.Element == BasicBlock {
     for block in other {
       insert(block)
     }
   }
 
   /// Returns true if the exclusive range contains `block`.
-  func contains(_ block: BasicBlock) -> Bool { inExclusiveRange.contains(block) }
-  
+  public func contains(_ block: BasicBlock) -> Bool { inExclusiveRange.contains(block) }
+
   /// Returns true if the inclusive range contains `block`.
-  func inclusiveRangeContains (_ block: BasicBlock) -> Bool {
+  public func inclusiveRangeContains (_ block: BasicBlock) -> Bool {
     worklist.hasBeenPushed(block)
   }
 
   /// Returns true if the range is valid and that's iff the begin block dominates all blocks of the range.
-  var isValid: Bool {
+  public var isValid: Bool {
     let entry = begin.parentFunction.entryBlock
     return begin == entry ||
       // If any block in the range is not dominated by `begin`, the range propagates back to the entry block.
@@ -117,12 +124,12 @@ struct BasicBlockRange : CustomStringConvertible, NoReflectionChildren {
   }
 
   /// Returns the end blocks.
-  var ends: LazyFilterSequence<Stack<BasicBlock>> {
+  public var ends: LazyFilterSequence<Stack<BasicBlock>> {
     inserted.lazy.filter { !contains($0) }
   }
 
   /// Returns the exit blocks.
-  var exits: LazySequence<FlattenSequence<
+  public var exits: LazySequence<FlattenSequence<
                     LazyMapSequence<LazyFilterSequence<Stack<BasicBlock>>,
                                     LazyFilterSequence<SuccessorArray>>>> {
     range.flatMap {
@@ -133,11 +140,11 @@ struct BasicBlockRange : CustomStringConvertible, NoReflectionChildren {
   }
 
   /// Returns the interior blocks.
-  var interiors: LazyFilterSequence<Stack<BasicBlock>> {
+  public var interiors: LazyFilterSequence<Stack<BasicBlock>> {
     inserted.lazy.filter { contains($0) && $0 != begin }
   }
   
-  var description: String {
+  public var description: String {
     return (isValid ? "" : "<invalid>\n") +
       """
       begin:     \(begin.name)
@@ -150,7 +157,7 @@ struct BasicBlockRange : CustomStringConvertible, NoReflectionChildren {
   }
 
   /// TODO: once we have move-only types, make this a real deinit.
-  mutating func deinitialize() {
+  public mutating func deinitialize() {
     worklist.deinitialize()
     inExclusiveRange.deinitialize()
     wasInserted.deinitialize()
diff --git a/SwiftCompilerSources/Sources/SIL/DataStructures/CMakeLists.txt b/SwiftCompilerSources/Sources/SIL/DataStructures/CMakeLists.txt
new file mode 100644
index 0000000000000..7564b469aa421
--- /dev/null
+++ b/SwiftCompilerSources/Sources/SIL/DataStructures/CMakeLists.txt
@@ -0,0 +1,14 @@
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See http://swift.org/LICENSE.txt for license information
+# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+
+swift_compiler_sources(SIL
+  BasicBlockRange.swift
+  InstructionRange.swift
+  Set.swift
+  Stack.swift
+  Worklist.swift)
diff --git a/SwiftCompilerSources/Sources/SIL/DataStructures/InstructionRange.swift b/SwiftCompilerSources/Sources/SIL/DataStructures/InstructionRange.swift
new file mode 100644
index 0000000000000..c2acd2ca7a35b
--- /dev/null
+++ b/SwiftCompilerSources/Sources/SIL/DataStructures/InstructionRange.swift
@@ -0,0 +1,277 @@
+//===--- InstructionRange.swift - a range of instructions -----------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+/// A range of instructions.
+///
+/// The `InstructionRange` defines a range from a dominating "begin" instruction to one or more "end" instructions.
+/// The range is "exclusive", which means that the "end" instructions are not part of the range.
+///
+/// One or more "potential" end instructions can be inserted.
+/// Though, not all inserted instructions end up as "end" instructions.
+///
+/// `InstructionRange` is useful for calculating the liverange of values.
+///
+/// The `InstructionRange` is similar to a `BasicBlockRange`, but defines the range
+/// in a "finer" granularity, i.e. on instructions instead of blocks.
+/// `InstructionRange` uses an underlying `BasicBlockRange` to compute the
+/// involved blocks of the instruction range.
+///
+/// There are several kind of instructions:
+/// * begin: it is a single instruction which dominates all instructions of the range
+/// * ends: all inserted instruction which are at the end of the range
+/// * exits: the first instructions of the exit blocks
+/// * interiors: all inserted instructions which are not end instructions.
+///
+/// See also `BasicBlockRange` for more information.
+///
+/// This type should be a move-only type, but unfortunately we don't have move-only
+/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
+/// destruct this data structure, e.g. in a `defer {}` block.
+public struct InstructionRange : CustomStringConvertible, NoReflectionChildren {
+
+  /// The underlying block range.
+  public private(set) var blockRange: BasicBlockRange
+
+  private var insertedInsts: InstructionSet
+
+  // For efficiency, this set does not include instructions in blocks which are not the begin or any end block.
+  private var inExclusiveRange: InstructionSet
+
+  public init(begin beginInst: Instruction, _ context: some Context) {
+    self = InstructionRange(beginBlock: beginInst.parentBlock, context)
+    self.inExclusiveRange.insert(beginInst)
+  }
+
+  // Note: 'ends' are simply the instructions to insert in the range. 'self.ends' might not return the same sequence
+  // as this 'ends' argument because 'self.ends' will not include block exits.
+  public init<S: Sequence>(begin beginInst: Instruction, ends: S, _ context: some Context) where S.Element: Instruction {
+    self = InstructionRange(begin: beginInst, context)
+    insert(contentsOf: ends)
+  }
+
+  public init(for value: Value, _ context: some Context) {
+    if let inst = value.definingInstruction {
+      self = InstructionRange(begin: inst, context)
+    } else if let arg = value as? Argument {
+      self = InstructionRange(beginBlock: arg.parentBlock, context)
+    } else {
+      fatalError("cannot build an instruction range for \(value)")
+    }
+  }
+
+  private init(beginBlock: BasicBlock, _ context: some Context) {
+    self.blockRange = BasicBlockRange(begin: beginBlock, context)
+    self.insertedInsts = InstructionSet(context)
+    self.inExclusiveRange = InstructionSet(context)
+  }
+
+  /// Insert a potential end instruction.
+  public mutating func insert(_ inst: Instruction) {
+    insertedInsts.insert(inst)
+    insertIntoRange(instructions: ReverseInstructionList(first: inst.previous))
+    if blockRange.insert(inst.parentBlock) {
+      // The first time an instruction is inserted in another block than the begin-block we need to insert
+      // instructions from the begin instruction to the end of the begin block.
+      // For subsequent insertions this is a no-op: `insertIntoRange` will return immediately because those
+      // instruction are already inserted.
+      insertIntoRange(instructions: blockRange.begin.instructions.reversed())
+    }
+  }
+
+  /// Insert a sequence of potential end instructions.
+  public mutating func insert<S: Sequence>(contentsOf other: S) where S.Element: Instruction {
+    for inst in other {
+      insert(inst)
+    }
+  }
+
+  /// Returns true if the exclusive range contains `inst`.
+  public func contains(_ inst: Instruction) -> Bool {
+    if inExclusiveRange.contains(inst) {
+      return true
+    }
+    let block = inst.parentBlock
+    return block != blockRange.begin && blockRange.contains(block)
+  }
+
+  /// Returns true if the inclusive range contains `inst`.
+  public func inclusiveRangeContains (_ inst: Instruction) -> Bool {
+    contains(inst) || insertedInsts.contains(inst)
+  }
+
+  /// Returns the end instructions.
+  ///
+  /// Warning: this returns `begin` if no instructions were inserted.
+  public var ends: LazyMapSequence<LazyFilterSequence<Stack<BasicBlock>>, Instruction> {
+    blockRange.ends.map {
+      $0.instructions.reversed().first(where: { insertedInsts.contains($0)})!
+    }
+  }
+
+  // Returns the exit blocks.
+  public var exitBlocks: LazySequence<FlattenSequence<
+                             LazyMapSequence<LazyFilterSequence<Stack<BasicBlock>>,
+                                    LazyFilterSequence<SuccessorArray>>>> {
+    blockRange.exits
+  }
+
+  /// Returns the exit instructions.
+  public var exits: LazyMapSequence<LazySequence<FlattenSequence<
+                                         LazyMapSequence<LazyFilterSequence<Stack<BasicBlock>>,
+                                               LazyFilterSequence<SuccessorArray>>>>,
+                             Instruction> {
+    blockRange.exits.lazy.map { $0.instructions.first! }
+  }
+
+  /// Returns the interior instructions.
+  public var interiors: LazySequence<FlattenSequence<
+                             LazyMapSequence<Stack<BasicBlock>,
+                                   LazyFilterSequence<ReverseInstructionList>>>> {
+    blockRange.inserted.lazy.flatMap {
+      var include = blockRange.contains($0)
+      return $0.instructions.reversed().lazy.filter {
+        if insertedInsts.contains($0) {
+          let isInterior = include
+          include = true
+          return isInterior
+        }
+        return false
+      }
+    }
+  }
+
+  public var begin: Instruction? {
+    blockRange.begin.instructions.first(where: inExclusiveRange.contains)
+  }
+
+  private mutating func insertIntoRange(instructions: ReverseInstructionList) {
+    for inst in instructions {
+      if !inExclusiveRange.insert(inst) {
+        return
+      }
+    }
+  }
+
+  public var description: String {
+    return (blockRange.isValid ? "" : "<invalid>\n") +
+      """
+      begin:    \(begin?.description ?? blockRange.begin.name)
+      ends:     \(ends.map { $0.description }.joined(separator: "\n          "))
+      exits:    \(exits.map { $0.description }.joined(separator: "\n          "))
+      interiors:\(interiors.map { $0.description }.joined(separator: "\n          "))
+      """
+  }
+
+  /// TODO: once we have move-only types, make this a real deinit.
+  public mutating func deinitialize() {
+    inExclusiveRange.deinitialize()
+    insertedInsts.deinitialize()
+    blockRange.deinitialize()
+  }
+}
+
+extension InstructionRange {
+  public enum PathOverlap {
+    // range:  ---
+    //          |    pathBegin
+    //          |        |
+    //          |     pathEnd
+    //         ---
+    case containsPath
+
+    // range:  ---
+    //          |    pathBegin
+    //         ---       |
+    //                pathEnd
+    case containsBegin
+
+    //               pathBegin
+    // range:  ---       |
+    //          |     pathEnd
+    //         ---
+    case containsEnd
+
+    //               pathBegin
+    // range:  ---       |
+    //          |        |
+    //         ---       |
+    //                pathEnd
+    case overlappedByPath
+
+    // either:       pathBegin
+    //                   |
+    //                pathEnd
+    // range:  ---
+    //          |
+    //         ---
+    // or:           pathBegin
+    //                   |
+    //                pathEnd
+    case disjoint
+  }
+
+  /// Return true if any exclusive path from `begin` to `end` includes an instruction in this exclusive range.
+  ///
+  /// Returns .containsBegin, if this range has the same begin and end as the path.
+  ///
+  /// Precondition: `begin` dominates `end`.
+  public func overlaps(pathBegin: Instruction, pathEnd: Instruction, _ context: some Context) -> PathOverlap {
+    assert(pathBegin != pathEnd, "expect an exclusive path")
+    if contains(pathBegin) {
+      // Note: pathEnd != self.begin here since self.contains(pathBegin)
+      if contains(pathEnd) { return .containsPath }
+      return .containsBegin
+    }
+    if contains(pathEnd) {
+      if let rangeBegin = self.begin, rangeBegin == pathEnd {
+        return .disjoint
+      }
+      return .containsEnd
+    }
+    // Neither end-point is contained. If a backward path walk encounters this range, then it must overlap this
+    // range. Otherwise, it is disjoint.
+    var backwardBlocks = BasicBlockWorklist(context)
+    defer { backwardBlocks.deinitialize() }
+    backwardBlocks.pushIfNotVisited(pathEnd.parentBlock)
+    while let block = backwardBlocks.pop() {
+      if blockRange.inclusiveRangeContains(block) {
+        // This range overlaps with this block, but there are still three possibilities:
+        // (1) range, pathBegin, pathEnd = disjoint         (range might not begin in this block)
+        // (2) pathBegin, pathEnd, range = disjoint         (pathBegin might not be in this block)
+        // (3) pathBegin, range, pathEnd = overlappedByPath (range or pathBegin might not be in this block)
+        //
+        // Walk backward from pathEnd to find either pathBegin or an instruction in this range.
+        // Both this range and the path may or may not begin in this block.
+        let endInBlock = block == pathEnd.parentBlock ? pathEnd : block.terminator
+        for inst in ReverseInstructionList(first: endInBlock) {
+          // Check pathBegin first because the range is exclusive.
+          if inst == pathBegin {
+            break
+          }
+          // Check inclusiveRangeContains() in case the range end is the first instruction in this block.
+          if inclusiveRangeContains(inst) {
+            return .overlappedByPath
+          }
+        }
+        // No instructions in this range occur between pathBegin and pathEnd.
+        return .disjoint
+      }
+      // No range blocks have been reached.
+      if block == pathBegin.parentBlock {
+        return .disjoint
+      }
+      backwardBlocks.pushIfNotVisited(contentsOf: block.predecessors)
+    }
+    fatalError("begin: \(pathBegin)\n  must dominate end: \(pathEnd)")
+  }
+}
+
diff --git a/SwiftCompilerSources/Sources/SIL/DataStructures/Set.swift b/SwiftCompilerSources/Sources/SIL/DataStructures/Set.swift
new file mode 100644
index 0000000000000..d631a35797811
--- /dev/null
+++ b/SwiftCompilerSources/Sources/SIL/DataStructures/Set.swift
@@ -0,0 +1,289 @@
+//===--- Set.swift - sets for basic blocks, values and instructions -------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SILBridging
+
+public protocol IntrusiveSet : CustomStringConvertible, NoReflectionChildren {
+  associatedtype Element
+
+  init(_ context: some Context)
+  mutating func insert(_ element: Element) -> Bool
+  mutating func erase(_ element: Element)
+  func contains(_ element: Element) -> Bool
+  mutating func deinitialize()
+}
+
+/// A set of basic blocks.
+///
+/// This is an extremely efficient implementation which does not need memory
+/// allocations or hash lookups.
+///
+/// This type should be a move-only type, but unfortunately we don't have move-only
+/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
+/// destruct this data structure, e.g. in a `defer {}` block.
+public struct BasicBlockSet : IntrusiveSet {
+
+  private let context: BridgedContext
+  private let bridged: BridgedBasicBlockSet
+    
+  public init(_ context: some Context) {
+    self.context = context._bridged
+    self.bridged = self.context.allocBasicBlockSet()
+  }
+
+  public func contains(_ block: BasicBlock) -> Bool {
+    bridged.contains(block.bridged)
+  }
+
+  /// Returns true if `block` was not contained in the set before inserting.
+  @discardableResult
+  public mutating func insert(_ block: BasicBlock) -> Bool {
+    bridged.insert(block.bridged)
+  }
+
+  public mutating func erase(_ block: BasicBlock) {
+    bridged.erase(block.bridged)
+  }
+
+  public var description: String {
+    let function = bridged.getFunction().function
+    let blockNames = function.blocks.enumerated().filter { contains($0.1) }
+                                                 .map { "bb\($0.0)"}
+    return "{" + blockNames.joined(separator: ", ") + "}"
+  }
+
+  /// TODO: once we have move-only types, make this a real deinit.
+  public mutating func deinitialize() {
+    context.freeBasicBlockSet(bridged)
+  }
+}
+
+/// A set of values.
+///
+/// This is an extremely efficient implementation which does not need memory
+/// allocations or hash lookups.
+///
+/// This type should be a move-only type, but unfortunately we don't have move-only
+/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
+/// destruct this data structure, e.g. in a `defer {}` block.
+public struct ValueSet : IntrusiveSet {
+
+  private let context: BridgedContext
+  private let bridged: BridgedNodeSet
+    
+  public init(_ context: some Context) {
+    self.context = context._bridged
+    self.bridged = self.context.allocNodeSet()
+  }
+
+  public func contains(_ value: Value) -> Bool {
+    bridged.containsValue(value.bridged)
+  }
+
+  /// Returns true if `value` was not contained in the set before inserting.
+  @discardableResult
+  public mutating func insert(_ value: Value) -> Bool {
+    bridged.insertValue(value.bridged)
+  }
+
+  public mutating func erase(_ value: Value) {
+    bridged.eraseValue(value.bridged)
+  }
+
+  public var description: String {
+    let function = bridged.getFunction().function
+    var d = "{\n"
+    for block in function.blocks {
+      for arg in block.arguments {
+        if contains(arg) {
+          d += arg.description
+        }
+      }
+      for inst in block.instructions {
+        for result in inst.results {
+          if contains(result) {
+            d += result.description
+          }
+        }
+      }
+    }
+    d += "}\n"
+    return d
+  }
+
+  /// TODO: once we have move-only types, make this a real deinit.
+  public mutating func deinitialize() {
+    context.freeNodeSet(bridged)
+  }
+}
+
+/// A set of instructions.
+///
+/// This is an extremely efficient implementation which does not need memory
+/// allocations or hash lookups.
+///
+/// This type should be a move-only type, but unfortunately we don't have move-only
+/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
+/// destruct this data structure, e.g. in a `defer {}` block.
+public struct SpecificInstructionSet<InstType: Instruction> : IntrusiveSet {
+
+  private let context: BridgedContext
+  private let bridged: BridgedNodeSet
+    
+  public init(_ context: some Context) {
+    self.context = context._bridged
+    self.bridged = self.context.allocNodeSet()
+  }
+
+  public func contains(_ inst: InstType) -> Bool {
+    bridged.containsInstruction(inst.bridged)
+  }
+
+  /// Returns true if `inst` was not contained in the set before inserting.
+  @discardableResult
+  public mutating func insert(_ inst: InstType) -> Bool {
+    bridged.insertInstruction(inst.bridged)
+  }
+
+  public mutating func erase(_ inst: InstType) {
+    bridged.eraseInstruction(inst.bridged)
+  }
+
+  public var description: String {
+    let function = bridged.getFunction().function
+    var d = "{\n"
+    for i in function.instructions {
+      if let inst = i as? InstType, contains(inst) {
+        d += inst.description + "\n"
+      }
+    }
+    d += "}\n"
+    return d
+  }
+
+  /// TODO: once we have move-only types, make this a real deinit.
+  public mutating func deinitialize() {
+    context.freeNodeSet(bridged)
+  }
+}
+
+/// An `InstructionSet` which also provides a `count` property.
+public struct SpecificInstructionSetWithCount<InstType: Instruction> : IntrusiveSet {
+  public private(set) var count = 0
+  private var underlyingSet: SpecificInstructionSet<InstType>
+
+  public init(_ context: some Context) {
+    self.underlyingSet = SpecificInstructionSet(context)
+  }
+
+  public func contains(_ inst: InstType) -> Bool { underlyingSet.contains(inst) }
+
+  public var isEmpty: Bool { count == 0 }
+
+  /// Returns true if `inst` was not contained in the set before inserting.
+  @discardableResult
+  public mutating func insert(_ inst: InstType) -> Bool {
+    if underlyingSet.insert(inst) {
+      count += 1
+      return true
+    }
+    return false
+  }
+
+  public mutating func erase(_ inst: InstType) {
+    if underlyingSet.contains(inst) {
+      count -= 1
+      assert(count >= 0)
+    }
+    underlyingSet.erase(inst)
+  }
+
+  public var description: String { underlyingSet.description }
+
+  public mutating func deinitialize() { underlyingSet.deinitialize() }
+}
+
+public typealias InstructionSet = SpecificInstructionSet<Instruction>
+public typealias InstructionSetWithCount = SpecificInstructionSetWithCount<Instruction>
+
+/// A set of operands.
+///
+/// This is an extremely efficient implementation which does not need memory
+/// allocations or hash lookups.
+///
+/// This type should be a move-only type, but unfortunately we don't have move-only
+/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
+/// destruct this data structure, e.g. in a `defer {}` block.
+public struct OperandSet : IntrusiveSet {
+
+  private let context: BridgedContext
+  private let bridged: BridgedOperandSet
+
+  public init(_ context: some Context) {
+    self.context = context._bridged
+    self.bridged = self.context.allocOperandSet()
+  }
+
+  public func contains(_ operand: Operand) -> Bool {
+    bridged.contains(operand.bridged)
+  }
+
+  /// Returns true if `inst` was not contained in the set before inserting.
+  @discardableResult
+  public mutating func insert(_ operand: Operand) -> Bool {
+    bridged.insert(operand.bridged)
+  }
+
+  public mutating func erase(_ operand: Operand) {
+    bridged.erase(operand.bridged)
+  }
+
+  public var description: String {
+    let function = bridged.getFunction().function
+    var d = "{\n"
+    for inst in function.instructions {
+      for op in inst.operands {
+        if contains(op) {
+          d += op.description
+        }
+      }
+    }
+    d += "}\n"
+    return d
+  }
+
+  /// TODO: once we have move-only types, make this a real deinit.
+  public mutating func deinitialize() {
+    context.freeOperandSet(bridged)
+  }
+}
+
+extension InstructionSet {
+  public mutating func insert<I: Instruction>(contentsOf source: some Sequence<I>) {
+    for inst in source {
+      _ = insert(inst)
+    }
+  }
+}
+
+extension IntrusiveSet {
+  public mutating func insert(contentsOf source: some Sequence<Element>) {
+    for element in source {
+      _ = insert(element)
+    }
+  }
+
+  public init(insertContentsOf source: some Sequence<Element>, _ context: some Context) {
+    self.init(context)
+    insert(contentsOf: source)
+  }
+}
diff --git a/SwiftCompilerSources/Sources/SIL/DataStructures/Stack.swift b/SwiftCompilerSources/Sources/SIL/DataStructures/Stack.swift
new file mode 100644
index 0000000000000..30444bdb7723b
--- /dev/null
+++ b/SwiftCompilerSources/Sources/SIL/DataStructures/Stack.swift
@@ -0,0 +1,305 @@
+//===--- Stack.swift - defines the Stack data structure -------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SILBridging
+
+/// A very efficient implementation of a stack, which can also be iterated over.
+///
+/// A Stack is the best choice for things like worklists, etc., if no random
+/// access is needed.
+/// Compared to Array, it does not require any memory allocations, because it
+/// uses a recycling bump pointer allocator for allocating the slabs.
+/// All operations have (almost) zero cost.
+///
+/// This type should be a move-only type, but unfortunately we don't have move-only
+/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
+/// destruct this data structure, e.g. in a `defer {}` block.
+public struct Stack<Element> : CollectionLikeSequence {
+
+  private let bridgedContext: BridgedContext
+  private var firstSlab = BridgedContext.Slab(nil)
+  private var lastSlab = BridgedContext.Slab(nil)
+  private var endIndex: Int = 0
+
+  private static var slabCapacity: Int {
+    BridgedContext.Slab.getCapacity() / MemoryLayout<Element>.stride
+  }
+
+  private func allocate(after lastSlab: BridgedContext.Slab? = nil) -> BridgedContext.Slab {
+    let lastSlab = lastSlab ?? BridgedContext.Slab(nil)
+    let newSlab = bridgedContext.allocSlab(lastSlab)
+    UnsafeMutableRawPointer(newSlab.data!).bindMemory(to: Element.self, capacity: Stack.slabCapacity)
+    return newSlab
+  }
+
+  private static func element(in slab: BridgedContext.Slab, at index: Int) -> Element {
+    return pointer(in: slab, at: index).pointee
+  }
+
+  private static func pointer(in slab: BridgedContext.Slab, at index: Int) -> UnsafeMutablePointer<Element> {
+    return UnsafeMutableRawPointer(slab.data!).assumingMemoryBound(to: Element.self) + index
+  }
+
+  public struct Iterator : IteratorProtocol {
+    var slab: BridgedContext.Slab
+    var index: Int
+    let lastSlab: BridgedContext.Slab
+    let endIndex: Int
+    
+    public mutating func next() -> Element? {
+      let end = (slab.data == lastSlab.data ? endIndex : slabCapacity)
+      
+      guard index < end else { return nil }
+    
+      let elem = Stack.element(in: slab, at: index)
+      index += 1
+      
+      if index >= end && slab.data != lastSlab.data {
+        slab = slab.getNext()
+        index = 0
+      }
+      return elem
+    }
+  }
+  
+  public init(_ context: some Context) { self.bridgedContext = context._bridged }
+
+  public func makeIterator() -> Iterator {
+    return Iterator(slab: firstSlab, index: 0, lastSlab: lastSlab, endIndex: endIndex)
+  }
+
+  public var first: Element? {
+    isEmpty ? nil : Stack.element(in: firstSlab, at: 0)
+  }
+
+  public var last: Element? {
+    isEmpty ? nil : Stack.element(in: lastSlab, at: endIndex &- 1)
+  }
+
+  public mutating func push(_ element: Element) {
+    if endIndex >= Stack.slabCapacity {
+      lastSlab = allocate(after: lastSlab)
+      endIndex = 0
+    } else if firstSlab.data == nil {
+      assert(endIndex == 0)
+      firstSlab = allocate()
+      lastSlab = firstSlab
+    }
+    Stack.pointer(in: lastSlab, at: endIndex).initialize(to: element)
+    endIndex += 1
+  }
+
+  /// The same as `push` to provide an Array-like append API.
+  public mutating func append(_ element: Element) { push(element) }
+
+  public mutating func append<S: Sequence>(contentsOf other: S) where S.Element == Element {
+    for elem in other {
+      append(elem)
+    }
+  }
+
+  public var isEmpty: Bool { return endIndex == 0 }
+
+  public mutating func pop() -> Element? {
+    if isEmpty {
+      return nil
+    }
+    assert(endIndex > 0)
+    endIndex -= 1
+    let elem = Stack.pointer(in: lastSlab, at: endIndex).move()
+    
+    if endIndex == 0 {
+      if lastSlab.data == firstSlab.data {
+        _ = bridgedContext.freeSlab(lastSlab)
+        firstSlab.data = nil
+        lastSlab.data = nil
+        endIndex = 0
+      } else {
+        lastSlab = bridgedContext.freeSlab(lastSlab)
+        endIndex = Stack.slabCapacity
+      }
+    }
+
+    return elem
+  }
+  
+  public mutating func removeAll() {
+    while pop() != nil { }
+  }
+
+  /// TODO: once we have move-only types, make this a real deinit.
+  public mutating func deinitialize() { removeAll() }
+}
+
+public extension Stack {
+  /// Mark a stack location for future iteration.
+  ///
+  /// TODO: Marker should be ~Escapable.
+  struct Marker {
+    let slab: BridgedContext.Slab
+    let index: Int
+  }
+
+  var top: Marker { Marker(slab: lastSlab, index: endIndex) }
+
+  struct Segment : CollectionLikeSequence {
+    let low: Marker
+    let high: Marker
+
+    public init(in stack: Stack, low: Marker, high: Marker) {
+      if low.slab.data == nil {
+        assert(low.index == 0, "invalid empty stack marker")
+        // `low == nil` and `high == nil` is a valid empty segment,
+        // even though `assertValid(marker:)` would return false.
+        if high.slab.data != nil {
+          stack.assertValid(marker: high)
+        }
+        self.low = Marker(slab: stack.firstSlab, index: 0)
+        self.high = high
+        return
+      }
+      stack.assertValid(marker: low)
+      stack.assertValid(marker: high)
+      self.low = low
+      self.high = high
+    }
+
+    public func makeIterator() -> Stack.Iterator {
+      return Iterator(slab: low.slab, index: low.index,
+                      lastSlab: high.slab, endIndex: high.index)
+    }
+  }
+
+  /// Assert that `marker` is valid based on the current `top`.
+  ///
+  /// This is an assert rather than a query because slabs can reuse
+  /// memory leading to a stale marker that appears valid.
+  func assertValid(marker: Marker) {
+    var currentSlab = lastSlab
+    var currentIndex = endIndex
+    while currentSlab.data != marker.slab.data {
+      assert(currentSlab.data != firstSlab.data, "Invalid stack marker")
+      currentSlab = currentSlab.getPrevious()
+      currentIndex = Stack.slabCapacity
+    }
+    assert(marker.index <= currentIndex, "Invalid stack marker")
+  }
+
+  /// Execute the `body` closure, passing it `self` for further
+  /// mutation of the stack and passing `marker` to mark the stack
+  /// position prior to executing `body`. `marker` must not escape the
+  /// `body` closure.
+  mutating func withMarker<R>(
+    _ body: (inout Stack<Element>, Marker) throws -> R) rethrows -> R {
+    return try body(&self, top)
+  }
+
+  /// Record a stack marker, execute a `body` closure, then execute a
+  /// `handleNewElements` closure with the Segment that contains all
+  /// elements that remain on the stack after being pushed on the
+  /// stack while executing `body`. `body` must push more elements
+  /// than it pops.
+  mutating func withMarker<R>(
+    pushElements body: (inout Stack) throws -> R,
+    withNewElements handleNewElements: ((Segment) -> ())
+  ) rethrows -> R {
+    return try withMarker { (stack: inout Stack<Element>, marker: Marker) in
+      let result = try body(&stack)
+      handleNewElements(Segment(in: stack, low: marker, high: stack.top))
+      return result
+    }
+  }
+}
+
+public struct StackWithCount<Element> : CollectionLikeSequence {
+  public private(set) var count = 0
+  private var underlyingStack: Stack<Element>
+  
+  public typealias Iterator = Stack<Element>.Iterator
+  
+  public init(_ context: some Context) {
+    self.underlyingStack = Stack<Element>(context)
+  }
+  
+  public func makeIterator() -> Stack<Element>.Iterator {
+    underlyingStack.makeIterator()
+  }
+  
+  public var first: Element? { underlyingStack.first }
+  public var last: Element? { underlyingStack.last }
+
+  public mutating func push(_ element: Element) {
+    count += 1
+    underlyingStack.push(element)
+  }
+
+  /// The same as `push` to provide an Array-like append API.
+  public mutating func append(_ element: Element) { push(element) }
+
+  public mutating func append<S: Sequence>(contentsOf other: S) where S.Element == Element {
+    for elem in other {
+      append(elem)
+    }
+  }
+
+  public var isEmpty: Bool { underlyingStack.isEmpty }
+
+  public mutating func pop() -> Element? {
+    if underlyingStack.isEmpty {
+      return nil
+    }
+    
+    count -= 1
+    return underlyingStack.pop()
+  }
+  
+  public mutating func removeAll() {
+    underlyingStack.removeAll()
+  }
+
+  /// TODO: once we have move-only types, make this a real deinit.
+  public mutating func deinitialize() { removeAll() }
+}
+
+public extension StackWithCount {
+  typealias Marker = Stack<Element>.Marker
+
+  struct Segment : CollectionLikeSequence {
+    var underlyingSegment: Stack<Element>.Segment
+    
+    public init(in stack: StackWithCount, low: Marker, high: Marker) {
+      underlyingSegment = Stack<Element>.Segment(in: stack.underlyingStack, low: low, high: high)
+    }
+    
+    public func makeIterator() -> StackWithCount.Iterator {
+      return underlyingSegment.makeIterator()
+    }
+  }
+  
+  var top: Marker { underlyingStack.top }
+
+  func assertValid(marker: Marker) { underlyingStack.assertValid(marker: marker) }
+
+  mutating func withMarker<R>(
+    _ body: (inout Stack<Element>, Marker) throws -> R) rethrows -> R {
+    return try underlyingStack.withMarker(body)
+  }
+
+  mutating func withMarker<R>(
+    pushElements body: (inout Stack<Element>) throws -> R,
+    withNewElements handleNewElements: ((Segment) -> ())
+  ) rethrows -> R {
+    return try underlyingStack.withMarker(pushElements: body) { [self] segment in
+      handleNewElements(Segment(in: self, low: segment.low, high: segment.high))
+    }
+  }
+}
diff --git a/SwiftCompilerSources/Sources/SIL/DataStructures/Worklist.swift b/SwiftCompilerSources/Sources/SIL/DataStructures/Worklist.swift
new file mode 100644
index 0000000000000..acdbe882c7a4a
--- /dev/null
+++ b/SwiftCompilerSources/Sources/SIL/DataStructures/Worklist.swift
@@ -0,0 +1,172 @@
+//===--- Worklist.swift ---------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+/// A utility for processing entities in a worklist.
+///
+/// A `Worklist` is basically a combination of a stack and a set.
+/// It can be used for typical worklist-processing algorithms.
+///
+/// This type should be a move-only type, but unfortunately we don't have move-only
+/// types yet. Therefore it's needed to call `deinitialize()` explicitly to
+/// destruct this data structure, e.g. in a `defer {}` block.
+public struct Worklist<Set: IntrusiveSet> : CustomStringConvertible, NoReflectionChildren {
+  public typealias Element = Set.Element
+  private var worklist: Stack<Element>
+  private var pushedElements: Set
+
+  public init(_ context: some Context) {
+    self.worklist = Stack(context)
+    self.pushedElements = Set(context)
+  }
+  
+  public mutating func pop() -> Element? { return worklist.pop() }
+
+  /// Pop and allow the popped element to be pushed again to the worklist.
+  public mutating func popAndForget() -> Element? {
+    if let element = worklist.pop() {
+      pushedElements.erase(element)
+      return element
+    }
+    return nil
+  }
+
+  public mutating func pushIfNotVisited(_ element: Element) {
+    if pushedElements.insert(element) {
+      worklist.append(element)
+    }
+  }
+
+  public mutating func pushIfNotVisited<S: Sequence>(contentsOf other: S) where S.Element == Element {
+    for element in other {
+      pushIfNotVisited(element)
+    }
+  }
+
+  /// Returns true if \p element was pushed to the worklist, regardless if it's already popped or not.
+  public func hasBeenPushed(_ element: Element) -> Bool { pushedElements.contains(element) }
+
+  public var isEmpty: Bool { worklist.isEmpty }
+
+  public var description: String {
+    """
+    worklist: \(worklist)
+    pushed:   \(pushedElements)
+    """
+  }
+
+  /// TODO: once we have move-only types, make this a real deinit.
+  public mutating func deinitialize() {
+    pushedElements.deinitialize()
+    worklist.deinitialize()
+  }
+}
+
+public typealias BasicBlockWorklist = Worklist<BasicBlockSet>
+public typealias InstructionWorklist = Worklist<InstructionSet>
+public typealias SpecificInstructionWorklist<InstType: Instruction> = Worklist<SpecificInstructionSet<InstType>>
+public typealias ValueWorklist = Worklist<ValueSet>
+public typealias OperandWorklist = Worklist<OperandSet>
+
+extension InstructionWorklist {
+  public mutating func pushPredecessors(of inst: Instruction, ignoring ignoreInst: Instruction? = nil) {
+    if let prev = inst.previous {
+      if prev != ignoreInst {
+        pushIfNotVisited(prev)
+      }
+    } else {
+      for predBlock in inst.parentBlock.predecessors {
+        let termInst = predBlock.terminator
+        if termInst != ignoreInst {
+          pushIfNotVisited(termInst)
+        }
+      }
+    }
+  }
+
+  public mutating func pushSuccessors(of inst: Instruction, ignoring ignoreInst: Instruction? = nil) {
+    if let succ = inst.next {
+      if succ != ignoreInst {
+        pushIfNotVisited(succ)
+      }
+    } else {
+      for succBlock in inst.parentBlock.successors {
+        let firstInst = succBlock.instructions.first!
+        if firstInst != ignoreInst {
+          pushIfNotVisited(firstInst)
+        }
+      }
+    }
+  }
+}
+
+/// A worklist for `Function`s.
+public struct FunctionWorklist {
+
+  // The current functions in the worklist.
+  public private(set) var functions = Array<Function>()
+
+  // All functions which were ever pushed to the worklist.
+  private var pushedFunctions = Set<Function>()
+
+  public init() {}
+
+  public mutating func pushIfNotVisited(_ function: Function) {
+    if pushedFunctions.insert(function).inserted {
+      functions.append(function)
+    }
+  }
+
+  public mutating func pushIfNotVisited<S: Sequence>(contentsOf functions: S) where S.Element == Function {
+    for f in functions {
+      pushIfNotVisited(f)
+    }
+  }
+
+  public mutating func pop() -> Function? {
+    return functions.popLast()
+  }
+}
+
+/// Like `ValueWorklist`, but allows pushing `Value`s from different functions -
+/// at the cost of a less efficient implementation.
+public struct CrossFunctionValueWorklist {
+
+  // The current values in the worklist.
+  private(set) var values = Array<Value>()
+
+  // All values which were ever pushed to the worklist.
+  private var pushedValues = Set<ObjectIdentifier>(minimumCapacity: 8)
+
+  public init() {
+    values.reserveCapacity(8)
+  }
+
+  public mutating func pop() -> Value? {
+    return values.popLast()
+  }
+
+  public mutating func pushIfNotVisited(_ value: Value) {
+    if pushedValues.insert(ObjectIdentifier(value)).inserted {
+      values.append(value)
+    }
+  }
+
+  public mutating func pushIfNotVisited<S: Sequence>(contentsOf values: S) where S.Element == Value {
+    for value in values {
+      pushIfNotVisited(value)
+    }
+  }
+
+  public func hasBeenPushed(_ value: Value) -> Bool {
+    return pushedValues.contains(ObjectIdentifier(value))
+  }
+}
diff --git a/SwiftCompilerSources/Sources/SIL/DeclRef.swift b/SwiftCompilerSources/Sources/SIL/DeclRef.swift
index 32ff660a6b151..a41660a57cc2a 100644
--- a/SwiftCompilerSources/Sources/SIL/DeclRef.swift
+++ b/SwiftCompilerSources/Sources/SIL/DeclRef.swift
@@ -30,4 +30,16 @@ public struct DeclRef: CustomStringConvertible, NoReflectionChildren {
   public static func ==(lhs: DeclRef, rhs: DeclRef) -> Bool {
     lhs.bridged.isEqualTo(rhs.bridged)
   }
+
+  /// Do we have enough information to determine all callees that could
+  /// be reached by calling the function represented by Decl?
+  public func calleesAreStaticallyKnowable(_ context: some Context) -> Bool {
+    context._bridged.calleesAreStaticallyKnowable(bridged)
+  }
+}
+
+extension DeclRef: DiagnosticArgument {
+  public func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
+    fn(bridged.asDiagnosticArgument())
+  }
 }
diff --git a/SwiftCompilerSources/Sources/SIL/Effects.swift b/SwiftCompilerSources/Sources/SIL/Effects.swift
index 9e106ccd3bf4f..311f4423c60aa 100644
--- a/SwiftCompilerSources/Sources/SIL/Effects.swift
+++ b/SwiftCompilerSources/Sources/SIL/Effects.swift
@@ -161,12 +161,7 @@ extension Function {
       break
     }
     if isProgramTerminationPoint {
-      // We can ignore any memory writes in a program termination point, because it's not relevant
-      // for the caller. But we need to consider memory reads, otherwise preceding memory writes
-      // would be eliminated by dead-store-elimination in the caller. E.g. String initialization
-      // for error strings which are printed by the program termination point.
-      // Regarding ownership: a program termination point must not touch any reference counted objects.
-      return SideEffects.GlobalEffects(memory: SideEffects.Memory(read: true))
+      return SideEffects.GlobalEffects.worstEffects.forProgramTerminationPoints
     }
     var result = SideEffects.GlobalEffects.worstEffects
     switch effectAttribute {
@@ -510,6 +505,14 @@ public struct SideEffects : CustomStringConvertible, NoReflectionChildren {
     /// This is true when the function (or a callee, transitively) contains a
     /// deinit barrier instruction.
     public var isDeinitBarrier: Bool
+    
+    public static var noEffects: GlobalEffects {
+      return GlobalEffects(memory: .noEffects, ownership: .noEffects, allocates: false, isDeinitBarrier: false)
+    }
+    
+    public var isOnlyReading: Bool {
+      return !memory.write && ownership == .noEffects && !allocates && !isDeinitBarrier
+    }
 
     /// When called with default arguments, it creates an "effect-free" GlobalEffects.
     public init(memory: Memory = Memory(read: false, write: false),
@@ -568,6 +571,18 @@ public struct SideEffects : CustomStringConvertible, NoReflectionChildren {
       return result
     }
 
+    /// Effects with all effects removed which are not relevant for program termination points (like `fatalError`).
+    public var forProgramTerminationPoints: GlobalEffects {
+      // We can ignore any memory writes in a program termination point, because it's not relevant
+      // for the caller. But we need to consider memory reads, otherwise preceding memory writes
+      // would be eliminated by dead-store-elimination in the caller. E.g. String initialization
+      // for error strings which are printed by the program termination point.
+      // Regarding ownership: a program termination point must not touch any reference counted objects.
+      // Also, the deinit-barrier effect is not relevant because functions like `fatalError` and `exit` are
+      // not accessing objects (except strings).
+      return GlobalEffects(memory: Memory(read: memory.read))
+    }
+
     public static var worstEffects: GlobalEffects {
       GlobalEffects(memory: .worstEffects, ownership: .worstEffects, allocates: true, isDeinitBarrier: true)
     }
@@ -636,6 +651,10 @@ public struct SideEffects : CustomStringConvertible, NoReflectionChildren {
       copy = copy || other.copy
       destroy = destroy || other.destroy
     }
+    
+    public static var noEffects: Ownership {
+      return Ownership(copy: false, destroy: false)
+    }
 
     public static var worstEffects: Ownership {
       Ownership(copy: true, destroy: true)
diff --git a/SwiftCompilerSources/Sources/SIL/ForwardingInstruction.swift b/SwiftCompilerSources/Sources/SIL/ForwardingInstruction.swift
index 174c0e30be8e9..276bef4a9ff92 100644
--- a/SwiftCompilerSources/Sources/SIL/ForwardingInstruction.swift
+++ b/SwiftCompilerSources/Sources/SIL/ForwardingInstruction.swift
@@ -53,7 +53,12 @@ extension ForwardingInstruction {
   public var forwardingOwnership: Ownership {
     Ownership(bridged: bridged.ForwardingInst_forwardingOwnership())
   }
-  
+
+  public func setForwardingOwnership(to ownership: Ownership, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.ForwardingInst_setForwardingOwnership(ownership._bridged)
+  }
+
   /// A forwarding instruction preserves reference counts if it has a dynamically non-trivial result in which all references are forwarded from the operand.
   ///
   /// A cast can only forward guaranteed values if it preserves reference counts. Such casts cannot release any references within their operand's value and cannot retain any references owned by their result.
diff --git a/SwiftCompilerSources/Sources/SIL/Function.swift b/SwiftCompilerSources/Sources/SIL/Function.swift
index 11db1fedf5f5b..45122979f77f9 100644
--- a/SwiftCompilerSources/Sources/SIL/Function.swift
+++ b/SwiftCompilerSources/Sources/SIL/Function.swift
@@ -36,6 +36,14 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
     hasher.combine(ObjectIdentifier(self))
   }
 
+  /// True if this function is referenced from anywhere within the module,
+  /// e.g. from a `function_ref` instruction.
+  public var isReferencedInModule: Bool { bridged.isReferencedInModule() }
+
+  /// True if this function should be optimized, i.e. the module is compiled with optimizations
+  /// and the function has no `@_optimize(none)` attribute.
+  public var shouldOptimize: Bool { bridged.shouldOptimize() }
+
   public var wasDeserializedCanonical: Bool { bridged.wasDeserializedCanonical() }
 
   public var isTrapNoReturn: Bool { bridged.isTrapNoReturn() }
@@ -45,21 +53,26 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
   public var isConvertPointerToPointerArgument: Bool { bridged.isConvertPointerToPointerArgument() }
 
   public var specializationLevel: Int { bridged.specializationLevel() }
-  
+
+  public var isSpecialization: Bool { bridged.isSpecialization() }
+
   public var hasOwnership: Bool { bridged.hasOwnership() }
 
   public var hasLoweredAddresses: Bool { bridged.hasLoweredAddresses() }
 
-  /// The lowered function type in the expansion context of self.
+  public var loweredFunctionType: CanonicalType {
+    CanonicalType(bridged: bridged.getLoweredFunctionType())
+  }
+
+  /// The lowered function type, with opaque archetypes erased.
   ///
-  /// Always expanding a function type means that the opaque result types
-  /// have the correct generic signature. For example:
+  /// For example:
   ///    @substituted <τ_0_0> () -> @out τ_0_0 for <some P>
   /// is lowered to this inside its module:
   ///    @substituted <τ_0_0> () -> @out τ_0_0 for <ActualResultType>
   /// and this outside its module
   ///    @substituted <τ_0_0> () -> @out τ_0_0 for <some P>
-  public var loweredFunctionType: CanonicalType {
+  public var loweredFunctionTypeInContext: CanonicalType {
     CanonicalType(bridged: bridged.getLoweredFunctionTypeInContext())
   }
 
@@ -77,13 +90,18 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
 
   /// Returns true if the function is a definition and not only an external declaration.
   ///
-  /// This is the case if the functioun contains a body, i.e. some basic blocks.
+  /// This is the case if the function contains a body, i.e. some basic blocks.
   public var isDefinition: Bool { blocks.first != nil }
 
   public var blocks : BasicBlockList { BasicBlockList(first: bridged.getFirstBlock().block) }
 
   public var entryBlock: BasicBlock { blocks.first! }
 
+  public func appendNewBlock(_ context: some MutatingContext) -> BasicBlock {
+    context.notifyBranchesChanged()
+    return context._bridged.appendBlock(bridged).block
+  }
+
   public var arguments: LazyMapSequence<ArgumentArray, FunctionArgument> {
     entryBlock.arguments.lazy.map { $0 as! FunctionArgument }
   }
@@ -153,9 +171,23 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
       bridged.hasSemanticsAttr(BridgedStringRef(data: buffer.baseAddress!, count: buffer.count))
     }
   }
-  public var isSerialized: Bool { bridged.isSerialized() }
+  public var isSerialized: Bool {
+    switch serializedKind {
+    case .notSerialized, .serializedForPackage:
+      return false
+    case .serialized:
+      return true
+    }
+  }
 
-  public var isAnySerialized: Bool { bridged.isAnySerialized() }
+  public var isAnySerialized: Bool {
+    switch serializedKind {
+    case .notSerialized:
+      return false
+    case .serialized, .serializedForPackage:
+      return true
+    }
+  }
 
   public enum SerializedKind {
     case notSerialized, serialized, serializedForPackage
@@ -187,7 +219,7 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
 
     // If Package-CMO is enabled, we serialize package, public, and @usableFromInline decls as
     // [serialized_for_package].
-    // Their bodies must not, however, leak into @inlinable functons (that are [serialized])
+    // Their bodies must not, however, leak into @inlinable functions (that are [serialized])
     // since they are inlined outside of their defining module.
     //
     // If this callee is [serialized_for_package], the caller must be either non-serialized
@@ -218,6 +250,34 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
       fatalError()
     }
   }
+  public func set(thunkKind: ThunkKind, _ context: some MutatingContext) {
+    context.notifyEffectsChanged()
+    switch thunkKind {
+    case .noThunk:                 bridged.setThunk(.IsNotThunk)
+    case .thunk:                   bridged.setThunk(.IsThunk)
+    case .reabstractionThunk:      bridged.setThunk(.IsReabstractionThunk)
+    case .signatureOptimizedThunk: bridged.setThunk(.IsSignatureOptimizedThunk)
+    }
+  }
+
+  public var accessorKindName: String? {
+    guard bridged.isAccessor() else {
+      return nil
+    }
+    return StringRef(bridged: bridged.getAccessorName()).string
+  }
+
+  public var isInitializer: Bool {
+    return bridged.isInitializer()
+  }
+
+  public var isDeinitializer: Bool {
+    return bridged.isDeinitializer()
+  }
+
+  public var isImplicit: Bool {
+    return bridged.isImplicit()
+  }
 
   /// True, if the function runs with a swift 5.1 runtime.
   /// Note that this is function specific, because inlinable functions are de-serialized
@@ -229,6 +289,10 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
   public var needsStackProtection: Bool {
     bridged.needsStackProtection()
   }
+  public func set(needStackProtection: Bool, _ context: some MutatingContext) {
+    context.notifyEffectsChanged()
+    bridged.setNeedStackProtection(needStackProtection)
+  }
 
   public var isDeinitBarrier: Bool {
     effects.sideEffects?.global.isDeinitBarrier ?? true
@@ -241,6 +305,7 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
     case noRuntime
     case noExistentials
     case noObjCRuntime
+    case manualOwnership
   }
 
   public var performanceConstraints: PerformanceConstraints {
@@ -251,13 +316,19 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
       case .NoRuntime: return .noRuntime
       case .NoExistentials: return .noExistentials
       case .NoObjCBridging: return .noObjCRuntime
+      case .ManualOwnership: return .manualOwnership
       default: fatalError("unknown performance constraint")
     }
   }
+  public func set(isPerformanceConstraint: Bool, _ context: some MutatingContext) {
+    context.notifyEffectsChanged()
+    bridged.setIsPerformanceConstraint(isPerformanceConstraint)
+  }
 
   public enum InlineStrategy {
     case automatic
     case never
+    case heuristicAlways
     case always
   }
 
@@ -265,12 +336,27 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
     switch bridged.getInlineStrategy() {
       case .InlineDefault: return .automatic
       case .NoInline: return .never
+      case .HeuristicAlwaysInline: return .heuristicAlways
       case .AlwaysInline: return .always
       default:
         fatalError()
     }
   }
 
+  public enum ABILanguage {
+    case C
+    case Swift
+  }
+
+  public var abi: ABILanguage {
+    switch bridged.getSILFunctionLanguage() {
+      case .C:     return .C
+      case .Swift: return .Swift
+      default:
+        fatalError()
+    }
+  }
+
   public enum SourceFileKind {
     case library         /// A normal .swift file.
     case main            /// A .swift file that can have top-level code.
@@ -301,7 +387,7 @@ public func != (lhs: Function, rhs: Function) -> Bool { lhs !== rhs }
 // Function conventions.
 extension Function {
   public var convention: FunctionConvention {
-    FunctionConvention(for: loweredFunctionType, in: self)
+    FunctionConvention(for: loweredFunctionTypeInContext, in: self)
   }
 
   public var argumentConventions: ArgumentConventions {
@@ -429,8 +515,8 @@ extension Function {
     }
   }
 
-  // Only to be called by PassContext
-  public func _modifyEffects(_ body: (inout FunctionEffects) -> ()) {
+  public func modifyEffects(_ context: some MutatingContext, _ body: (inout FunctionEffects) -> ()) {
+    context.notifyEffectsChanged()
     body(&effects)
   }
 }
@@ -574,6 +660,10 @@ extension Function {
                                                 atIndex: calleeArgIdx,
                                                 withConvention: convention)
         return effects.memory.read
+      },
+      // isDeinitBarrier
+      { (f: BridgedFunction) -> Bool in
+        return f.function.getSideEffects().isDeinitBarrier
       }
     )
   }
diff --git a/SwiftCompilerSources/Sources/SIL/FunctionConvention.swift b/SwiftCompilerSources/Sources/SIL/FunctionConvention.swift
index a95ea62ee2f1e..eabb84031085b 100644
--- a/SwiftCompilerSources/Sources/SIL/FunctionConvention.swift
+++ b/SwiftCompilerSources/Sources/SIL/FunctionConvention.swift
@@ -26,10 +26,14 @@ public struct FunctionConvention : CustomStringConvertible {
   let functionType: CanonicalType
   let hasLoweredAddresses: Bool
 
-  init(for functionType: CanonicalType, in function: Function) {
+  public init(for functionType: CanonicalType, in function: Function) {
+    self.init(for: functionType, hasLoweredAddresses: function.hasLoweredAddresses)
+  }
+
+  public init(for functionType: CanonicalType, hasLoweredAddresses: Bool) {
     assert(!functionType.hasTypeParameter, "requires contextual type")
     self.functionType = functionType
-    self.hasLoweredAddresses = function.hasLoweredAddresses
+    self.hasLoweredAddresses = hasLoweredAddresses
   }
 
   /// All results including the error.
@@ -53,11 +57,15 @@ public struct FunctionConvention : CustomStringConvertible {
     : SILFunctionType_getNumPackResults(functionType.bridged)
   }
 
-  /// Indirect results including the error.
-  public var indirectSILResults: LazyFilterSequence<Results> {
-    hasLoweredAddresses
-    ? results.lazy.filter { $0.isSILIndirect }
-    : results.lazy.filter { $0.convention == .pack }
+  /// Returns the indirect result - including the error - at `index`.
+  public func indirectSILResult(at index: Int) -> ResultInfo {
+    let indirectResults = results.lazy.filter {
+      hasLoweredAddresses ? $0.isSILIndirect : $0.convention == .pack
+    }
+    // Note that subscripting a LazyFilterCollection (with the base index, e.g. `Int`) does not work
+    // as expected, because it returns the nth element of the base collection!
+    // Therefore we need to implement the subscript "manually".
+    return indirectResults.enumerated().first{ $0.offset == index }!.element
   }
 
   public var parameters: Parameters {
@@ -90,6 +98,20 @@ public struct FunctionConvention : CustomStringConvertible {
     return SILFunctionType_getLifetimeDependencies(functionType.bridged).count() != 0
   }
 
+  public var hasGuaranteedResult: Bool {
+    if results.count != 1 {
+      return false
+    }
+    return results[0].convention == .guaranteed
+  }
+
+  public var hasGuaranteedAddressResult: Bool {
+    if results.count != 1 {
+      return false
+    }
+    return results[0].convention == .guaranteedAddress
+  }
+
   public var description: String {
     var str = functionType.description
     for paramIdx in 0..<parameters.count {
@@ -125,7 +147,7 @@ public struct ResultInfo : CustomStringConvertible {
       return hasLoweredAddresses || type.isExistentialArchetypeWithError()
     case .pack:
       return true
-    case .owned, .unowned, .unownedInnerPointer, .autoreleased:
+    case .owned, .unowned, .unownedInnerPointer, .autoreleased, .guaranteed, .guaranteedAddress:
       return false
     }
   }
@@ -209,7 +231,7 @@ public struct ParameterInfo : CustomStringConvertible {
 }
 
 extension FunctionConvention {
-  public struct Parameters : Collection {
+  public struct Parameters : RandomAccessCollection {
     let bridged: BridgedParameterInfoArray
     let hasLoweredAddresses: Bool
 
@@ -350,6 +372,14 @@ public enum ResultConvention : CustomStringConvertible {
   /// The caller is responsible for destroying this return value.  Its type is non-trivial.
   case owned
 
+  /// The caller is responsible for using the returned address within a valid
+  /// scope. This is valid only for borrow and mutate accessors.
+  case guaranteedAddress
+
+  /// The caller is responsible for using the returned value within a valid
+  /// scope. This is valid only for borrow accessors.
+  case guaranteed
+
   /// The caller is not responsible for destroying this return value.  Its type may be trivial, or it may simply be offered unsafely.  It is valid at the instant of the return, but further operations may invalidate it.
   case unowned
 
@@ -389,6 +419,10 @@ public enum ResultConvention : CustomStringConvertible {
       return "autoreleased"
     case .pack:
       return "pack"
+    case .guaranteed:
+      return "guaranteed"
+    case .guaranteedAddress:
+      return "guaranteedAddress"
     }
   }
 }
@@ -401,8 +435,11 @@ extension ResultInfo {
     self.convention = ResultConvention(bridged: bridged.convention)
     self.hasLoweredAddresses = hasLoweredAddresses
   }
-  init(bridged: OptionalBridgedResultInfo, hasLoweredAddresses: Bool) {
-    self.type = BridgedASTType(type: bridged.type!)
+  init?(bridged: OptionalBridgedResultInfo, hasLoweredAddresses: Bool) {
+    guard let t = bridged.type else {
+      return nil
+    }
+    self.type = BridgedASTType(type: t)
     self.convention = ResultConvention(bridged: bridged.convention)
     self.hasLoweredAddresses = hasLoweredAddresses
   }
@@ -417,6 +454,8 @@ extension ResultConvention {
       case .UnownedInnerPointer: self = .unownedInnerPointer
       case .Autoreleased:        self = .autoreleased
       case .Pack:                self = .pack
+      case .Guaranteed:          self = .guaranteed
+      case .GuaranteedAddress:   self = .guaranteedAddress
       default:
         fatalError("unsupported result convention")
     }
diff --git a/SwiftCompilerSources/Sources/SIL/GlobalVariable.swift b/SwiftCompilerSources/Sources/SIL/GlobalVariable.swift
index b96c1bed46241..3f7cf04b1b4bc 100644
--- a/SwiftCompilerSources/Sources/SIL/GlobalVariable.swift
+++ b/SwiftCompilerSources/Sources/SIL/GlobalVariable.swift
@@ -29,6 +29,8 @@ final public class GlobalVariable : CustomStringConvertible, HasShortDescription
 
   public var shortDescription: String { name.string }
 
+  public var type: Type { Type(bridged: bridged.getType()) }
+
   public var isLet: Bool { bridged.isLet() }
 
   public var linkage: Linkage { bridged.getLinkage().linkage }
@@ -67,6 +69,8 @@ final public class GlobalVariable : CustomStringConvertible, HasShortDescription
     return bridged.canBeInitializedStatically()
   }
 
+  /// True if the global has an attribute, like `@const` or `@section` which requires the global to be
+  /// initialized statically.
   public var mustBeInitializedStatically: Bool {
     return bridged.mustBeInitializedStatically()
   }
diff --git a/SwiftCompilerSources/Sources/SIL/Instruction.swift b/SwiftCompilerSources/Sources/SIL/Instruction.swift
index 64dbfe771f393..d979f467e92e7 100644
--- a/SwiftCompilerSources/Sources/SIL/Instruction.swift
+++ b/SwiftCompilerSources/Sources/SIL/Instruction.swift
@@ -63,6 +63,15 @@ public class Instruction : CustomStringConvertible, Hashable {
     return allOperands[(allOperands.count - typeOperands.count) ..< allOperands.count]
   }
 
+  public final func setOperand(at index : Int, to value: Value, _ context: some MutatingContext) {
+    if let apply = self as? FullApplySite, apply.isCallee(operand: operands[index]) {
+      context.notifyCallsChanged()
+    }
+    context.notifyInstructionsChanged()
+    bridged.setOperand(index, value.bridged)
+    context.notifyInstructionChanged(self)
+  }
+
   fileprivate var resultCount: Int { 0 }
   fileprivate func getResult(index: Int) -> Value { fatalError() }
 
@@ -83,6 +92,16 @@ public class Instruction : CustomStringConvertible, Hashable {
     return Location(bridged: bridged.getLocation())
   }
 
+  public final func move(before otherInstruction: Instruction, _ context: some MutatingContext) {
+    BridgedContext.moveInstructionBefore(bridged, otherInstruction.bridged)
+    context.notifyInstructionsChanged()
+  }
+  
+  public final func copy(before otherInstruction: Instruction, _ context: some MutatingContext) {
+    BridgedContext.copyInstructionBefore(bridged, otherInstruction.bridged)
+    context.notifyInstructionsChanged()
+  }
+
   public var mayTrap: Bool { false }
 
   final public var mayHaveSideEffects: Bool {
@@ -149,7 +168,8 @@ public class Instruction : CustomStringConvertible, Hashable {
   /// their operand.
   public final var isIncidentalUse: Bool {
     switch self {
-    case is DebugValueInst, is FixLifetimeInst, is EndLifetimeInst:
+    case is DebugValueInst, is FixLifetimeInst, is EndLifetimeInst,
+         is IgnoredUseInst:
       return true
     default:
       return isEndOfScopeMarker
@@ -162,6 +182,10 @@ public class Instruction : CustomStringConvertible, Hashable {
   public static func ==(lhs: Instruction, rhs: Instruction) -> Bool {
     lhs === rhs
   }
+  
+  public func isIdenticalTo(_ otherInst: Instruction) -> Bool {
+    return bridged.isIdenticalTo(otherInst.bridged)
+  }
 
   public func hash(into hasher: inout Hasher) {
     hasher.combine(ObjectIdentifier(self))
@@ -205,6 +229,12 @@ public class SingleValueInstruction : Instruction, Value {
   }
 
   public var isLexical: Bool { false }
+
+  /// Replaces all uses with `replacement` and then erases the instruction.
+  public final func replace(with replacement: Value, _ context: some MutatingContext) {
+    uses.replaceAll(with: replacement, context)
+    context.erase(instruction: self)
+  }
 }
 
 public final class MultipleValueInstructionResult : Value, Hashable {
@@ -246,6 +276,14 @@ public class MultipleValueInstruction : Instruction {
   fileprivate final override func getResult(index: Int) -> Value {
     bridged.MultipleValueInstruction_getResult(index).result
   }
+
+  /// Replaces all uses with the result of `replacement` and then erases the instruction.
+  public final func replace(with replacement: MultipleValueInstruction, _ context: some MutatingContext) {
+    for (origResult, newResult) in zip(self.results, replacement.results) {
+      origResult.uses.replaceAll(with: newResult, context)
+    }
+    context.erase(instruction: self)
+  }
 }
 
 /// Instructions, which have a single operand (not including type-dependent operands).
@@ -309,16 +347,14 @@ final public class AssignInst : Instruction, StoringInstruction {
   }
 }
 
-final public class AssignByWrapperInst : Instruction, StoringInstruction {}
-
 final public class AssignOrInitInst : Instruction, StoringInstruction {}
 
 /// Instruction that copy or move from a source to destination address.
 public protocol SourceDestAddrInstruction : Instruction {
   var sourceOperand: Operand { get }
   var destinationOperand: Operand { get }
-  var isTakeOfSrc: Bool { get }
-  var isInitializationOfDest: Bool { get }
+  var isTakeOfSource: Bool { get }
+  var isInitializationOfDestination: Bool { get }
 }
 
 extension SourceDestAddrInstruction {
@@ -329,22 +365,33 @@ extension SourceDestAddrInstruction {
 }
 
 final public class CopyAddrInst : Instruction, SourceDestAddrInstruction {
-  public var isTakeOfSrc: Bool {
+  public var isTakeOfSource: Bool {
     bridged.CopyAddrInst_isTakeOfSrc()
   }
-  public var isInitializationOfDest: Bool {
+  public func set(isTakeOfSource: Bool, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.CopyAddrInst_setIsTakeOfSrc(isTakeOfSource)
+    context.notifyInstructionChanged(self)
+  }
+
+  public var isInitializationOfDestination: Bool {
     bridged.CopyAddrInst_isInitializationOfDest()
   }
+  public func set(isInitializationOfDestination: Bool, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.CopyAddrInst_setIsInitializationOfDest(isInitializationOfDestination)
+    context.notifyInstructionChanged(self)
+  }
 }
 
 final public class ExplicitCopyAddrInst : Instruction, SourceDestAddrInstruction {
   public var source: Value { return sourceOperand.value }
   public var destination: Value { return destinationOperand.value }
 
-  public var isTakeOfSrc: Bool {
+  public var isTakeOfSource: Bool {
     bridged.ExplicitCopyAddrInst_isTakeOfSrc()
   }
-  public var isInitializationOfDest: Bool {
+  public var isInitializationOfDestination: Bool {
     bridged.ExplicitCopyAddrInst_isInitializationOfDest()
   }
 }
@@ -449,17 +496,17 @@ public enum VariableScopeInstruction {
     scopeBegin.uses.lazy.filter { $0.endsLifetime || $0.instruction is ExtendLifetimeInst }
   }
 
-  // TODO: with SIL verification, we might be able to make varDecl non-Optional.
-  public var varDecl: VarDecl? {
-    if let debugVarDecl = instruction.debugVarDecl {
-      return debugVarDecl
-    }
+  // TODO: assert that VarDecl is valid whenever isFromVarDecl returns tyue.
+  public func findVarDecl() -> VarDecl? {
     // SILGen may produce double var_decl instructions for the same variable:
     //   %box = alloc_box [var_decl] "x"
     //   begin_borrow %box [var_decl]
     //
-    // Assume that, if the begin_borrow or move_value does not have its own debug_value, then it must actually be
-    // associated with its operand's var_decl.
+    // Therefore, first check if begin_borrow or move_value has any debug_value users.
+    if let debugVarDecl = instruction.findVarDeclFromDebugUsers() {
+      return debugVarDecl
+    }
+    // Otherwise, assume that the var_decl is associated with its operand's var_decl.
     return instruction.operands[0].value.definingInstruction?.findVarDecl()
   }
 }
@@ -471,17 +518,33 @@ extension Instruction {
       return varDeclInst.varDecl
     }
     if let varScopeInst = VariableScopeInstruction(self) {
-      return varScopeInst.varDecl
+      return varScopeInst.findVarDecl()
     }
-    return debugVarDecl
+    return findVarDeclFromDebugUsers()
   }
 
-  var debugVarDecl: VarDecl? {
+  func findVarDeclFromDebugUsers() -> VarDecl? {
     for result in results {
-      for use in result.uses {
-        if let debugVal = use.instruction as? DebugValueInst {
-          return debugVal.varDecl
-        }
+      if let varDecl = result.findVarDeclFromDebugUsers() {
+        return varDecl
+      }
+    }
+    return nil
+  }
+}
+
+extension Value {
+  public func findVarDecl() -> VarDecl? {
+    if let arg = self as? Argument {
+      return arg.findVarDecl()
+    }
+    return findVarDeclFromDebugUsers()
+  }
+
+  func findVarDeclFromDebugUsers() -> VarDecl? {
+    for use in uses {
+      if let debugVal = use.instruction as? DebugValueInst {
+        return debugVal.varDecl
       }
     }
     return nil
@@ -525,16 +588,12 @@ final public class UnconditionalCheckedCastAddrInst : Instruction, SourceDestAdd
     CanonicalType(bridged: bridged.UnconditionalCheckedCastAddr_getTargetFormalType())
   }
 
-  public var isTakeOfSrc: Bool { true }
-  public var isInitializationOfDest: Bool { true }
+  public var isTakeOfSource: Bool { true }
+  public var isInitializationOfDestination: Bool { true }
   public override var mayTrap: Bool { true }
 
-  public var isolatedConformances: CastingIsolatedConformances {
-    switch bridged.UnconditionalCheckedCastAddr_getIsolatedConformances() {
-    case .Allow: .allow
-    case .Prohibit: .prohibit
-    @unknown default: fatalError("Unhandled CastingIsolatedConformances")
-    }
+  public var checkedCastOptions: CheckedCastInstOptions {
+     .init(storage: bridged.UnconditionalCheckedCastAddr_getCheckedCastOptions().storage)
   }
 }
 
@@ -550,6 +609,12 @@ final public class RebindMemoryInst : SingleValueInstruction {}
 
 public class RefCountingInst : Instruction, UnaryInstruction {
   public var isAtomic: Bool { bridged.RefCountingInst_getIsAtomic() }
+
+  public final func setAtomicity(isAtomic: Bool, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.RefCountingInst_setIsAtomic(isAtomic)
+    context.notifyInstructionChanged(self)
+  }
 }
 
 final public class StrongRetainInst : RefCountingInst {
@@ -615,6 +680,7 @@ final public class ExtendLifetimeInst : Instruction, UnaryInstruction {}
 final public class InjectEnumAddrInst : Instruction, UnaryInstruction, EnumInstruction {
   public var `enum`: Value { operand.value }
   public var caseIndex: Int { bridged.InjectEnumAddrInst_caseIndex() }
+  public var element: EnumElementDecl { bridged.InjectEnumAddrInst_element().getAs(EnumElementDecl.self) }
 }
 
 //===----------------------------------------------------------------------===//
@@ -630,11 +696,7 @@ extension Deallocation {
 }
 
 
-final public class DeallocStackInst : Instruction, UnaryInstruction, Deallocation {
-  public var allocstack: AllocStackInst {
-    return operand.value as! AllocStackInst
-  }
-}
+final public class DeallocStackInst : Instruction, UnaryInstruction, Deallocation {}
 
 final public class DeallocStackRefInst : Instruction, UnaryInstruction, Deallocation {
   public var allocRef: AllocRefInstBase { operand.value as! AllocRefInstBase }
@@ -644,7 +706,9 @@ final public class DeallocRefInst : Instruction, UnaryInstruction, Deallocation
 
 final public class DeallocPartialRefInst : Instruction, Deallocation {}
 
-final public class DeallocBoxInst : Instruction, UnaryInstruction, Deallocation {}
+final public class DeallocBoxInst : Instruction, UnaryInstruction, Deallocation {
+  public var isDeadEnd: Bool { bridged.DeallocBoxInst_isDeadEnd() }
+}
 
 final public class DeallocExistentialBoxInst : Instruction, UnaryInstruction, Deallocation {}
 
@@ -666,6 +730,11 @@ final public class LoadInst : SingleValueInstruction, LoadInstruction {
   public var loadOwnership: LoadOwnership {
     LoadOwnership(rawValue: bridged.LoadInst_getLoadOwnership())!
   }
+  public func set(ownership: LoadInst.LoadOwnership, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.LoadInst_setOwnership(ownership.rawValue)
+    context.notifyInstructionChanged(self)
+  }
 }
 
 final public class LoadWeakInst : SingleValueInstruction, LoadInstruction {}
@@ -706,8 +775,8 @@ class UncheckedRefCastInst : SingleValueInstruction, UnaryInstruction {
 
 final public
 class UncheckedRefCastAddrInst : Instruction, SourceDestAddrInstruction {
-  public var isTakeOfSrc: Bool { true }
-  public var isInitializationOfDest: Bool { true }
+  public var isTakeOfSource: Bool { true }
+  public var isInitializationOfDestination: Bool { true }
 }
 
 final public class UncheckedAddrCastInst : SingleValueInstruction, UnaryInstruction {
@@ -719,7 +788,9 @@ final public class UncheckedTrivialBitCastInst : SingleValueInstruction, UnaryIn
 }
 
 final public class UncheckedBitwiseCastInst : SingleValueInstruction, UnaryInstruction {}
-final public class UncheckedValueCastInst : SingleValueInstruction, UnaryInstruction {}
+final public class UncheckedValueCastInst : SingleValueInstruction, UnaryInstruction {
+  public var fromValue: Value { operand.value }
+}
 
 final public class RefToRawPointerInst : SingleValueInstruction, UnaryInstruction {}
 final public class RefToUnmanagedInst : SingleValueInstruction, UnaryInstruction {}
@@ -754,6 +825,11 @@ class PointerToAddressInst : SingleValueInstruction, UnaryInstruction {
     }
     return Int(exactly: maybeAlign)
   }
+  public func set(alignment: Int?, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.PointerToAddressInst_setAlignment(UInt64(alignment ?? 0))
+    context.notifyInstructionChanged(self)
+  }
 }
 
 public protocol IndexingInstruction: SingleValueInstruction {
@@ -812,7 +888,9 @@ final public
 class DeinitExistentialValueInst : Instruction {}
 
 final public
-class OpenExistentialAddrInst : SingleValueInstruction, UnaryInstruction {}
+class OpenExistentialAddrInst : SingleValueInstruction, UnaryInstruction {
+  public var isImmutable: Bool { bridged.OpenExistentialAddr_isImmutable() }
+}
 
 final public
 class OpenExistentialBoxInst : SingleValueInstruction, UnaryInstruction {}
@@ -843,8 +921,12 @@ final public class TypeValueInst: SingleValueInstruction, UnaryInstruction {
     CanonicalType(bridged: bridged.TypeValueInst_getParamType())
   }
 
-  public var value: Int {
-    bridged.TypeValueInst_getValue()
+  /// Returns the value of the Integer type is known and fits into an `Int`.
+  public var value: Int? {
+    if paramType.isInteger {
+      return paramType.valueOfInteger
+    }
+    return nil
   }
 }
 
@@ -881,10 +963,22 @@ final public class GlobalAddrInst : GlobalAccessInstruction, VarDeclInstruction
   public var dependencyToken: Value? {
     operands.count == 1 ? operands[0].value : nil
   }
+
+  public func clearToken(_ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.GlobalAddrInst_clearToken()
+    context.notifyInstructionChanged(self)
+  }
 }
 
 final public class GlobalValueInst : GlobalAccessInstruction {
   public var isBare: Bool { bridged.GlobalValueInst_isBare() }
+
+  public func setIsBare(_ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.GlobalValueInst_setIsBare()
+    context.notifyInstructionChanged(self)
+  }
 }
 
 final public class BaseAddrForOffsetInst : SingleValueInstruction {}
@@ -1001,6 +1095,12 @@ final public class RefElementAddrInst : SingleValueInstruction, UnaryInstruction
 
   public var isImmutable: Bool { bridged.RefElementAddrInst_isImmutable() }
   
+  public func set(isImmutable: Bool, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.RefElementAddrInst_setImmutable(isImmutable)
+    context.notifyInstructionChanged(self)
+  }
+
   public var varDecl: VarDecl? {
     bridged.RefElementAddr_getDecl().getAs(VarDecl.self)
   }
@@ -1013,6 +1113,14 @@ final public class RefTailAddrInst : SingleValueInstruction, UnaryInstruction {
 }
 
 final public class KeyPathInst : SingleValueInstruction {
+  public var substitutionMap: SubstitutionMap {
+    SubstitutionMap(bridged: bridged.KeyPathInst_getSubstitutionMap())
+  }
+
+  public var hasPattern: Bool {
+    bridged.KeyPathInst_hasPattern()
+  }
+
   public override func visitReferencedFunctions(_ cl: (Function) -> ()) {
     var results = BridgedInstruction.KeyPathFunctionResults()
     for componentIdx in 0..<bridged.KeyPathInst_getNumComponents() {
@@ -1041,12 +1149,8 @@ class UnconditionalCheckedCastInst : SingleValueInstruction, UnaryInstruction {
     CanonicalType(bridged: bridged.UnconditionalCheckedCast_getTargetFormalType())
   }
 
-  public var isolatedConformances: CastingIsolatedConformances {
-    switch bridged.UnconditionalCheckedCast_getIsolatedConformances() {
-    case .Allow: .allow
-    case .Prohibit: .prohibit
-    @unknown default: fatalError("Unhandled CastingIsolatedConformances")
-    }
+  public var checkedCastOptions: CheckedCastInstOptions {
+     .init(storage: bridged.UnconditionalCheckedCast_getCheckedCastOptions().storage)
   }
 }
 
@@ -1071,7 +1175,7 @@ class ThinToThickFunctionInst : SingleValueInstruction, UnaryInstruction {
 final public class ThickToObjCMetatypeInst : SingleValueInstruction {}
 final public class ObjCToThickMetatypeInst : SingleValueInstruction {}
 
-final public class CopyBlockInst : SingleValueInstruction {}
+final public class CopyBlockInst : SingleValueInstruction, UnaryInstruction {}
 final public class CopyBlockWithoutEscapingInst : SingleValueInstruction {}
 
 final public
@@ -1105,58 +1209,50 @@ public enum MarkDependenceKind: Int32 {
 }
 
 public protocol MarkDependenceInstruction: Instruction {
-  var baseOperand: Operand { get }
-  var base: Value { get }
   var dependenceKind: MarkDependenceKind { get }
-  func resolveToNonEscaping()
-  func settleToEscaping()
 }
 
 extension MarkDependenceInstruction {
   public var isNonEscaping: Bool { dependenceKind == .NonEscaping }
   public var isUnresolved: Bool { dependenceKind == .Unresolved }
+
+  public var valueOrAddressOperand: Operand { operands[0] }
+  public var valueOrAddress: Value { valueOrAddressOperand.value }
+  public var baseOperand: Operand { operands[1] }
+  public var base: Value { baseOperand.value }
+
+  public func resolveToNonEscaping(_ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.MarkDependenceInstruction_resolveToNonEscaping()
+    context.notifyInstructionChanged(self)
+  }
+  public func settleToEscaping(_ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.MarkDependenceInstruction_settleToEscaping()
+    context.notifyInstructionChanged(self)
+  }
 }
 
 final public class MarkDependenceInst : SingleValueInstruction, MarkDependenceInstruction {
-  public var valueOperand: Operand { operands[0] }
-  public var baseOperand: Operand { operands[1] }
+  public var valueOperand: Operand { valueOrAddressOperand }
   public var value: Value { return valueOperand.value }
-  public var base: Value { return baseOperand.value }
 
   public var dependenceKind: MarkDependenceKind {
     MarkDependenceKind(rawValue: bridged.MarkDependenceInst_dependenceKind().rawValue)!
   }
 
-  public func resolveToNonEscaping() {
-    bridged.MarkDependenceInst_resolveToNonEscaping()
-  }
-
-  public func settleToEscaping() {
-    bridged.MarkDependenceInst_settleToEscaping()
-  }
-
   public var hasScopedLifetime: Bool {
     return isNonEscaping && type.isObject && ownership == .owned && type.isEscapable(in: parentFunction)
   }
 }
 
 final public class MarkDependenceAddrInst : Instruction, MarkDependenceInstruction {
-  public var addressOperand: Operand { operands[0] }
-  public var baseOperand: Operand { operands[1] }
+  public var addressOperand: Operand { valueOrAddressOperand }
   public var address: Value { return addressOperand.value }
-  public var base: Value { return baseOperand.value }
 
   public var dependenceKind: MarkDependenceKind {
     MarkDependenceKind(rawValue: bridged.MarkDependenceAddrInst_dependenceKind().rawValue)!
   }
-
-  public func resolveToNonEscaping() {
-    bridged.MarkDependenceAddrInst_resolveToNonEscaping()
-  }
-
-  public func settleToEscaping() {
-    bridged.MarkDependenceAddrInst_settleToEscaping()
-  }
 }
 
 final public class RefToBridgeObjectInst : SingleValueInstruction {
@@ -1168,7 +1264,7 @@ final public class BridgeObjectToRefInst : SingleValueInstruction, UnaryInstruct
 
 final public class BridgeObjectToWordInst : SingleValueInstruction, UnaryInstruction {}
 
-final public class BorrowedFromInst : SingleValueInstruction, BorrowIntroducingInstruction {
+final public class BorrowedFromInst : SingleValueInstruction, BeginBorrowInstruction {
   public var borrowedValue: Value { operands[0].value }
   public var borrowedPhi: Phi { Phi(borrowedValue)! }
   public var enclosingOperands: OperandArray {
@@ -1178,6 +1274,8 @@ final public class BorrowedFromInst : SingleValueInstruction, BorrowIntroducingI
   public var enclosingValues: LazyMapSequence<LazySequence<OperandArray>.Elements, Value> {
     enclosingOperands.values
   }
+
+  public var scopeEndingOperands: LazyFilterSequence<UseList> { uses.endingLifetime }
 }
 
 final public class ProjectBoxInst : SingleValueInstruction, UnaryInstruction {
@@ -1223,6 +1321,10 @@ final public class EndCOWMutationInst : SingleValueInstruction, UnaryInstruction
   public var doKeepUnique: Bool { bridged.EndCOWMutationInst_doKeepUnique() }
 }
 
+final public class EndCOWMutationAddrInst : Instruction, UnaryInstruction {
+  public var address: Value { operand.value }
+}
+
 final public
 class ClassifyBridgeObjectInst : SingleValueInstruction, UnaryInstruction {}
 
@@ -1290,13 +1392,47 @@ final public class IsUniqueInst : SingleValueInstruction, UnaryInstruction {}
 
 final public class DestroyNotEscapedClosureInst : SingleValueInstruction, UnaryInstruction {}
 
-final public class MarkUnresolvedNonCopyableValueInst: SingleValueInstruction, UnaryInstruction {}
+final public class MarkUnresolvedNonCopyableValueInst: SingleValueInstruction, UnaryInstruction {
+  // The raw values must match swift::MarkUnresolvedNonCopyableValueInst::CheckKind
+  public enum CheckKind: Int {
+    case invalid = 0
+
+    /// A signal to the move only checker to perform checking that allows for
+    /// this value to be consumed along its boundary (in the case of let/var
+    /// semantics) and also written over in the case of var semantics. NOTE: Of
+    /// course this still implies the value cannot be copied and can be consumed
+    /// only once along all program paths.
+    case consumableAndAssignable
+
+    /// A signal to the move only checker to perform no consume or assign
+    /// checking. This forces the result of this instruction owned value to
+    /// never be consumed (for let/var semantics) or assigned over (for var
+    /// semantics). Of course, we still allow for non-consuming uses.
+    case noConsumeOrAssign
+
+    /// A signal to the move checker that the given value cannot be consumed,
+    /// but is allowed to be assigned over. This is used for situations like
+    /// global_addr/ref_element_addr/closure escape where we do not want to
+    /// allow for the user to take the value (leaving the memory in an
+    /// uninitialized state), but we are ok with the user assigning a new value,
+    /// completely assigning over the value at once.
+    case assignableButNotConsumable
+
+    /// A signal to the move checker that the given value cannot be consumed or
+    /// assigned, but is allowed to be initialized. This is used for situations
+    /// like class initializers.
+    case initableButNotConsumable
+  }
+
+  var checkKind: CheckKind { CheckKind(rawValue: bridged.MarkUnresolvedNonCopyableValue_getCheckKind())! }
+  var isStrict: Bool { bridged.MarkUnresolvedNonCopyableValue_isStrict() }
+}
 
 final public class MarkUnresolvedReferenceBindingInst : SingleValueInstruction {}
 
 final public class MarkUnresolvedMoveAddrInst : Instruction, SourceDestAddrInstruction {
-  public var isTakeOfSrc: Bool { true }
-  public var isInitializationOfDest: Bool { true }
+  public var isTakeOfSource: Bool { true }
+  public var isInitializationOfDestination: Bool { true }
 }
 
 final public class CopyableToMoveOnlyWrapperValueInst: SingleValueInstruction, UnaryInstruction {}
@@ -1325,6 +1461,10 @@ final public class ObjectInst : SingleValueInstruction {
 final public class VectorInst : SingleValueInstruction {
 }
 
+final public class VectorBaseAddrInst : SingleValueInstruction, UnaryInstruction {
+  public var vector: Value { operand.value }
+}
+
 final public class DifferentiableFunctionInst: SingleValueInstruction {}
 
 final public class LinearFunctionInst: SingleValueInstruction {}
@@ -1346,6 +1486,7 @@ final public class AllocStackInst : SingleValueInstruction, Allocation, DebugVar
   public var hasDynamicLifetime: Bool { bridged.AllocStackInst_hasDynamicLifetime() }
   public var isFromVarDecl: Bool { bridged.AllocStackInst_isFromVarDecl() }
   public var usesMoveableValueDebugInfo: Bool { bridged.AllocStackInst_usesMoveableValueDebugInfo() }
+  public override var isLexical: Bool { bridged.AllocStackInst_isLexical() }
 
   public var varDecl: VarDecl? {
     bridged.AllocStack_getDecl().getAs(VarDecl.self)
@@ -1355,7 +1496,7 @@ final public class AllocStackInst : SingleValueInstruction, Allocation, DebugVar
     return bridged.AllocStack_hasVarInfo() ? bridged.AllocStack_getVarInfo() : nil
   }
 
-  public var deallocations: LazyMapSequence<LazyFilterSequence<UseList>, Instruction> {
+  public var deallocations: LazyMapSequence<LazyFilterSequence<UseList>, DeallocStackInst> {
     uses.users(ofType: DeallocStackInst.self)
   }
 }
@@ -1367,6 +1508,12 @@ public class AllocRefInstBase : SingleValueInstruction, Allocation {
     bridged.AllocRefInstBase_canAllocOnStack()
   }
 
+  public final func setIsStackAllocatable(_ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.AllocRefInstBase_setIsStackAllocatable()
+    context.notifyInstructionChanged(self)
+  }
+
   final public var tailAllocatedCounts: OperandArray {
     let numTailTypes = bridged.AllocRefInstBase_getNumTailTypes()
     return operands[0..<numTailTypes]
@@ -1379,6 +1526,12 @@ public class AllocRefInstBase : SingleValueInstruction, Allocation {
 
 final public class AllocRefInst : AllocRefInstBase {
   public var isBare: Bool { bridged.AllocRefInst_isBare() }
+
+  public func setIsBare(_ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.AllocRefInst_setIsBare()
+    context.notifyInstructionChanged(self)
+  }
 }
 
 final public class AllocRefDynamicInst : AllocRefInstBase {
@@ -1401,6 +1554,8 @@ final public class AllocBoxInst : SingleValueInstruction, Allocation, DebugVaria
   public var debugVariable: DebugVariable? {
     return bridged.AllocBox_hasVarInfo() ? bridged.AllocBox_getVarInfo() : nil
   }
+
+  public var hasDynamicLifetime: Bool { bridged.AllocBoxInst_hasDynamicLifetime() }
 }
 
 final public class AllocExistentialBoxInst : SingleValueInstruction, Allocation {
@@ -1413,10 +1568,8 @@ final public class AllocExistentialBoxInst : SingleValueInstruction, Allocation
 /// An instruction whose side effects extend across a scope including other instructions. These are always paired with a
 /// scope ending instruction such as `begin_access` (ending with `end_access`) and `begin_borrow` (ending with
 /// `end_borrow`).
-public protocol ScopedInstruction {
-  var instruction: Instruction { get }
-
-  var endOperands: LazyFilterSequence<UseList> { get }
+public protocol ScopedInstruction: Instruction {
+  var scopeEndingOperands: LazyFilterSequence<UseList> { get }
 
   var endInstructions: EndInstructions { get }
 }
@@ -1425,43 +1578,32 @@ extension Instruction {
   /// Return the sequence of use points of any instruction.
   public var endInstructions: EndInstructions {
     if let scopedInst = self as? ScopedInstruction {
-      return .scoped(scopedInst.endOperands.users)
+      return .scoped(scopedInst.scopeEndingOperands.users)
     }
     return .single(self)
   }
 }
 
-/// Instructions beginning a borrow-scope which must be ended by `end_borrow`.
-public protocol BorrowIntroducingInstruction : SingleValueInstruction, ScopedInstruction {
-}
-
-extension BorrowIntroducingInstruction {
-  public var instruction: Instruction { get { self } }
+/// Single-value instructions beginning a borrow-scope which end with an `end_borrow` or a branch to a re-borrow phi.
+/// See also `BeginBorrowValue` which represents all kind of `Value`s which begin a borrow scope.
+public protocol BeginBorrowInstruction : SingleValueInstruction, ScopedInstruction {
 }
 
 final public class EndBorrowInst : Instruction, UnaryInstruction {
   public var borrow: Value { operand.value }
 }
 
-extension BorrowIntroducingInstruction {
-  public var endOperands: LazyFilterSequence<UseList> {
-    return uses.lazy.filter { $0.instruction is EndBorrowInst }
-  }
-}
-
-final public class BeginBorrowInst : SingleValueInstruction, UnaryInstruction, BorrowIntroducingInstruction {
+final public class BeginBorrowInst : SingleValueInstruction, UnaryInstruction, BeginBorrowInstruction {
   public var borrowedValue: Value { operand.value }
 
   public override var isLexical: Bool { bridged.BeginBorrow_isLexical() }
   public var hasPointerEscape: Bool { bridged.BeginBorrow_hasPointerEscape() }
   public var isFromVarDecl: Bool { bridged.BeginBorrow_isFromVarDecl() }
 
-  public var endOperands: LazyFilterSequence<UseList> {
-    return uses.endingLifetime
-  }
+  public var scopeEndingOperands: LazyFilterSequence<UseList> { uses.endingLifetime }
 }
 
-final public class LoadBorrowInst : SingleValueInstruction, LoadInstruction, BorrowIntroducingInstruction {
+final public class LoadBorrowInst : SingleValueInstruction, LoadInstruction, BeginBorrowInstruction {
 
   // True if the invariants on `load_borrow` have not been checked and should not be strictly enforced.
   //
@@ -1469,10 +1611,12 @@ final public class LoadBorrowInst : SingleValueInstruction, LoadInstruction, Bor
   // code using noncopyable types that consumes or mutates a memory location while that location is borrowed,
   // but the move-only checker must diagnose those problems before canonical SIL is formed.
   public var isUnchecked: Bool { bridged.LoadBorrowInst_isUnchecked() }
+
+  public var scopeEndingOperands: LazyFilterSequence<UseList> { uses.endingLifetime }
 }
 
-final public class StoreBorrowInst : SingleValueInstruction, StoringInstruction, BorrowIntroducingInstruction {
-  var allocStack: AllocStackInst {
+final public class StoreBorrowInst : SingleValueInstruction, StoringInstruction, BeginBorrowInstruction {
+  public var allocStack: AllocStackInst {
     var dest = destination
     if let mark = dest as? MarkUnresolvedNonCopyableValueInst {
       dest = mark.operand.value
@@ -1480,7 +1624,13 @@ final public class StoreBorrowInst : SingleValueInstruction, StoringInstruction,
     return dest as! AllocStackInst
   }
 
-  public var endBorrows: LazyMapSequence<LazyFilterSequence<UseList>, Instruction> {
+  public var scopeEndingOperands: LazyFilterSequence<UseList> {
+    return self.uses.lazy.filter { $0.instruction is EndBorrowInst }
+  }
+
+  public var endBorrows: LazyMapSequence<LazyFilterSequence<UseList>, EndBorrowInst> {
+    // A `store_borrow` is an address value.
+    // Only `end_borrow`s (with this address operand) can end such a borrow scope.
     uses.users(ofType: EndBorrowInst.self)
   }
 }
@@ -1496,6 +1646,38 @@ final public class BeginAccessInst : SingleValueInstruction, UnaryInstruction {
   public var accessKind: AccessKind {
     AccessKind(rawValue: bridged.BeginAccessInst_getAccessKind())!
   }
+  public func set(accessKind: AccessKind, context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.BeginAccess_setAccessKind(accessKind.rawValue)
+    context.notifyInstructionChanged(self)
+  }
+
+  // The raw values must match SILAccessEnforcement.
+  public enum Enforcement: Int {
+    /// The access's enforcement has not yet been determined.
+    case unknown = 0
+
+    /// The access is statically known to not conflict with other accesses.
+    case `static` = 1
+
+    /// The access is not statically known to not conflict with anything and must be dynamically checked.
+    case dynamic = 2
+
+    /// The access is not statically known to not conflict with anything but dynamic checking should
+    /// be suppressed, leaving it undefined behavior.
+    case unsafe = 3
+
+    /// Access to pointers that are signed via pointer authentication.
+    case signed = 4
+  }
+  public var enforcement: Enforcement {
+    Enforcement(rawValue: bridged.BeginAccessInst_getEnforcement())!
+  }
+  public func set(enforcement: Enforcement, context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.BeginAccess_setEnforcement(enforcement.rawValue)
+    context.notifyInstructionChanged(self)
+  }
 
   public var isStatic: Bool { bridged.BeginAccessInst_isStatic() }
   public var isUnsafe: Bool { bridged.BeginAccessInst_isUnsafe() }
@@ -1505,7 +1687,7 @@ final public class BeginAccessInst : SingleValueInstruction, UnaryInstruction {
   public typealias EndAccessInstructions = LazyMapSequence<LazyFilterSequence<UseList>, EndAccessInst>
 
   public var endAccessInstructions: EndAccessInstructions {
-    endOperands.map { $0.instruction as! EndAccessInst }
+    scopeEndingOperands.map { $0.instruction as! EndAccessInst }
   }
 }
 
@@ -1516,9 +1698,7 @@ final public class EndAccessInst : Instruction, UnaryInstruction {
 }
 
 extension BeginAccessInst : ScopedInstruction {
-  public var instruction: Instruction { get { self } }
-
-  public var endOperands: LazyFilterSequence<UseList> {
+  public var scopeEndingOperands: LazyFilterSequence<UseList> {
     return uses.lazy.filter { $0.instruction is EndAccessInst }
   }
 }
@@ -1531,15 +1711,19 @@ final public class EndUnpairedAccessInst : Instruction {}
 
 final public class BeginApplyInst : MultipleValueInstruction, FullApplySite {
   public var numArguments: Int { bridged.BeginApplyInst_numArguments() }
+  public var isCalleeAllocated: Bool { bridged.BeginApplyInst_isCalleeAllocated() }
 
   public var singleDirectResult: Value? { nil }
   public var singleDirectErrorResult: Value? { nil }
 
-  public var token: Value { getResult(index: resultCount - 1) }
+  public var token: Value { getResult(index: resultCount - (isCalleeAllocated ? 2 : 1)) }
 
   public var yieldedValues: Results {
-    Results(inst: self, numResults: resultCount - 1)
+    Results(inst: self, numResults: resultCount - (isCalleeAllocated ? 2 : 1))
   }
+
+  public var isNonThrowing: Bool { bridged.BeginApplyInst_getNonThrowing() }
+  public var isNonAsync: Bool { bridged.BeginApplyInst_getNonAsync() }
 }
 
 final public class EndApplyInst : SingleValueInstruction, UnaryInstruction {
@@ -1553,9 +1737,7 @@ final public class AbortApplyInst : Instruction, UnaryInstruction {
 }
 
 extension BeginApplyInst : ScopedInstruction {
-  public var instruction: Instruction { get { self } }
-
-  public var endOperands: LazyFilterSequence<UseList> {
+  public var scopeEndingOperands: LazyFilterSequence<UseList> {
     return token.uses.lazy.filter { $0.isScopeEndingUse }
   }
 }
@@ -1660,6 +1842,11 @@ public class TermInst : Instruction {
   }
   
   public var isFunctionExiting: Bool { false }
+
+  public final func replaceBranchTarget(from fromBlock: BasicBlock, to toBlock: BasicBlock, _ context: some MutatingContext) {
+    context.notifyBranchesChanged()
+    bridged.TermInst_replaceBranchTarget(fromBlock.bridged, toBlock.bridged)
+  }
 }
 
 final public class UnreachableInst : TermInst {
@@ -1680,6 +1867,9 @@ final public class ThrowAddrInst : TermInst {
 }
 
 final public class YieldInst : TermInst {
+  public func convention(of operand: Operand) -> ArgumentConvention {
+    return bridged.YieldInst_getConvention(operand.bridged).convention
+  }
 }
 
 final public class UnwindInst : TermInst {
@@ -1787,16 +1977,21 @@ final public class DynamicMethodBranchInst : TermInst {
 final public class AwaitAsyncContinuationInst : TermInst, UnaryInstruction {
 }
 
+public struct CheckedCastInstOptions {
+  var storage: UInt8 = 0
+  
+  var bridged: BridgedInstruction.CheckedCastInstOptions {
+    .init(storage: storage)
+  }
+  
+  var isolatedConformances: CastingIsolatedConformances {
+    return (storage & 0x01) != 0 ? .prohibit : .allow
+  }
+}
+
 public enum CastingIsolatedConformances {
   case allow
   case prohibit
-
-  var bridged: BridgedInstruction.CastingIsolatedConformances {
-    switch self {
-    case .allow: return .Allow
-    case .prohibit: return .Prohibit
-    }
-  }
 }
 
 final public class CheckedCastBranchInst : TermInst, UnaryInstruction {
@@ -1808,12 +2003,8 @@ final public class CheckedCastBranchInst : TermInst, UnaryInstruction {
     bridged.CheckedCastBranch_updateSourceFormalTypeFromOperandLoweredType()
   }
 
-  public var isolatedConformances: CastingIsolatedConformances {
-    switch bridged.CheckedCastBranch_getIsolatedConformances() {
-    case .Allow: return .allow
-    case .Prohibit: return .prohibit
-    default: fatalError("Bad CastingIsolatedConformances value")
-    }
+  public var checkedCastOptions: CheckedCastInstOptions {
+     .init(storage: bridged.CheckedCastBranch_getCheckedCastOptions().storage)
   }
 }
 
@@ -1856,12 +2047,8 @@ final public class CheckedCastAddrBranchInst : TermInst {
     }
   }
 
-  public var isolatedConformances: CastingIsolatedConformances {
-    switch bridged.CheckedCastAddrBranch_getIsolatedConformances() {
-    case .Allow: .allow
-    case .Prohibit: .prohibit
-    @unknown default: fatalError("Unhandled CastingIsolatedConformances")
-    }
+  public var checkedCastOptions: CheckedCastInstOptions {
+     .init(storage: bridged.CheckedCastAddrBranch_getCheckedCastOptions().storage)
   }
 }
 
diff --git a/SwiftCompilerSources/Sources/SIL/Location.swift b/SwiftCompilerSources/Sources/SIL/Location.swift
index 62e2245739792..51844f88ff49f 100644
--- a/SwiftCompilerSources/Sources/SIL/Location.swift
+++ b/SwiftCompilerSources/Sources/SIL/Location.swift
@@ -11,8 +11,21 @@
 //===----------------------------------------------------------------------===//
 
 import SILBridging
+import AST
 
-public struct Location: Equatable, CustomStringConvertible {
+/// Represents a location in source code.
+/// `Location` is used in SIL and by the Optimizer.
+///
+/// When compiling a Swift file, `Location` is basically a `SourceLoc` + information about the
+/// containing debug scope. In this case the `SourceLoc` is directly retrieved from the AST nodes.
+///
+/// However, for debug info which is de-serialized from a swiftmodule file, the location consists of
+/// a filename + line and column indices. From such a location, a `SourceLoc` can only be created by
+/// loading the file with `DiagnosticEngine.getLocationFromExternalSource`.
+///
+/// In case of parsing textual SIL (e.g. with `sil-opt`), which does _not_ contain debug line
+/// information, the location is also a `SourceLoc` which points to the textual SIL.
+public struct Location: ProvidingSourceLocation, Equatable, CustomStringConvertible {
   let bridged: BridgedLocation
 
   public var description: String {
@@ -20,20 +33,52 @@ public struct Location: Equatable, CustomStringConvertible {
   }
   
   public var sourceLoc: SourceLoc? {
-    return SourceLoc(bridged: bridged.getSourceLocation())
+    if hasValidLineNumber {
+      return SourceLoc(bridged: bridged.getSourceLocation())
+    }
+    return nil
+  }
+
+  public var fileNameAndPosition: (path: StringRef, line: Int, column: Int)? {
+    if bridged.isFilenameAndLocation() {
+      let loc = bridged.getFilenameAndLocation()
+      return (StringRef(bridged: loc.path), loc.line, loc.column)
+    }
+    return nil
+  }
+
+  public func getSourceLocation(diagnosticEngine: DiagnosticEngine) -> SourceLoc? {
+    if let sourceLoc = sourceLoc {
+      return sourceLoc
+    }
+    if let (path, line, column) = fileNameAndPosition {
+      return diagnosticEngine.getLocationFromExternalSource(path: path, line: line, column: column)
+    }
+    return nil
   }
 
   /// Keeps the debug scope but marks it as auto-generated.
-  public var autoGenerated: Location {
+  public var asAutoGenerated: Location {
     Location(bridged: bridged.getAutogeneratedLocation())
   }
 
+  public var asCleanup: Location {
+    Location(bridged: bridged.getCleanupLocation())
+  }
+
+  public func withScope(of other: Location) -> Location {
+    Location(bridged: bridged.withScopeOf(other.bridged))
+  }
+
   public var hasValidLineNumber: Bool { bridged.hasValidLineNumber() }
   public var isAutoGenerated: Bool { bridged.isAutoGenerated() }
   public var isInlined: Bool { bridged.isInlined() }
 
   public var isDebugSteppable: Bool { hasValidLineNumber && !isAutoGenerated }
 
+  /// The `Decl` if the location refers to a declaration.
+  public var decl: Decl? { bridged.getDecl().decl }
+
   public static func ==(lhs: Location, rhs: Location) -> Bool {
     lhs.bridged.isEqualTo(rhs.bridged)
   }
diff --git a/SwiftCompilerSources/Sources/SIL/Operand.swift b/SwiftCompilerSources/Sources/SIL/Operand.swift
index 541b6f8f6a5d4..cda27da5f934c 100644
--- a/SwiftCompilerSources/Sources/SIL/Operand.swift
+++ b/SwiftCompilerSources/Sources/SIL/Operand.swift
@@ -27,6 +27,10 @@ public struct Operand : CustomStringConvertible, NoReflectionChildren, Equatable
 
   public var value: Value { bridged.getValue().value }
 
+  public func set(to value: Value, _ context: some MutatingContext) {
+    instruction.setOperand(at: index, to: value, context)
+  }
+
   public static func ==(lhs: Operand, rhs: Operand) -> Bool {
     return lhs.bridged.op == rhs.bridged.op
   }
@@ -45,6 +49,12 @@ public struct Operand : CustomStringConvertible, NoReflectionChildren, Equatable
 
   public func canAccept(ownership: Ownership) -> Bool { bridged.canAcceptOwnership(ownership._bridged) }
 
+  public func changeOwnership(from: Ownership, to: Ownership, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.changeOwnership(from._bridged, to._bridged)
+    context.notifyInstructionChanged(instruction)
+  }
+
   public var description: String { "operand #\(index) of \(instruction)" }
 }
 
@@ -94,10 +104,6 @@ public struct OperandArray : RandomAccessCollection, CustomReflectable {
       base: OptionalBridgedOperand(op: base.advancedBy(bounds.lowerBound).op),
       count: bounds.upperBound - bounds.lowerBound)
   }
-
-  public var values: LazyMapSequence<LazySequence<OperandArray>.Elements, Value> {
-    self.lazy.map { $0.value }
-  }
 }
 
 public struct UseList : CollectionLikeSequence {
@@ -133,6 +139,10 @@ public struct UseList : CollectionLikeSequence {
 }
 
 extension Sequence where Element == Operand {
+  public var values: LazyMapSequence<Self, Value> {
+    self.lazy.map { $0.value }
+  }
+
   public var singleUse: Operand? {
     var result: Operand? = nil
     for op in self {
@@ -154,11 +164,15 @@ extension Sequence where Element == Operand {
     self.lazy.filter { !($0.instruction is DebugValueInst) }
   }
 
-  public func filterUsers<I: Instruction>(ofType: I.Type) -> LazyFilterSequence<Self> {
+  public func filterUses<I: Instruction>(ofType: I.Type) -> LazyFilterSequence<Self> {
     self.lazy.filter { $0.instruction is I }
   }
 
-  public func ignoreUsers<I: Instruction>(ofType: I.Type) -> LazyFilterSequence<Self> {
+  public func filterUsers<I: Instruction>(ofType: I.Type) -> LazyMapSequence<LazyFilterSequence<Self>, I> {
+    self.lazy.filter { $0.instruction is I }.lazy.map { $0.instruction as! I }
+  }
+
+  public func ignoreUses<I: Instruction>(ofType: I.Type) -> LazyFilterSequence<Self> {
     self.lazy.filter { !($0.instruction is I) }
   }
 
@@ -167,11 +181,11 @@ extension Sequence where Element == Operand {
   }
 
   public func getSingleUser<I: Instruction>(ofType: I.Type) -> I? {
-    filterUsers(ofType: I.self).singleUse?.instruction as? I
+    filterUses(ofType: I.self).singleUse?.instruction as? I
   }
 
   public func getSingleUser<I: Instruction>(notOfType: I.Type) -> Instruction? {
-    ignoreUsers(ofType: I.self).singleUse?.instruction
+    ignoreUses(ofType: I.self).singleUse?.instruction
   }
 
   public var endingLifetime: LazyFilterSequence<Self> {
@@ -186,10 +200,10 @@ extension Sequence where Element == Operand {
     self.lazy.filter{ $0.instruction is I }.lazy.map { $0.instruction as! I }
   }
 
-  // This overload which returns a Sequence of `Instruction` and not a Sequence of `I` is used for APIs, like
-  // `InstructionSet.insert(contentsOf:)`, which require a sequence of `Instruction`.
-  public func users<I: Instruction>(ofType: I.Type) -> LazyMapSequence<LazyFilterSequence<Self>, Instruction> {
-    self.lazy.filter{ $0.instruction is I }.users
+  public func replaceAll(with replacement: Value, _ context: some MutatingContext) {
+    for use in self {
+      use.set(to: replacement, context)
+    }
   }
 }
 
@@ -197,6 +211,12 @@ extension Value {
   public var users: LazyMapSequence<UseList, Instruction> { uses.users }
 }
 
+extension Instruction {
+  public func isUsing(_ value: Value) -> Bool {
+    return operands.contains { $0.value == value }
+  }
+}
+
 extension Operand {
   /// Return true if this operation will store a full value into this
   /// operand's address.
@@ -262,7 +282,7 @@ public enum OperandOwnership {
   
   /// Escape a pointer into a value which cannot be tracked or verified.
   ///
-  /// PointerEscape  operands indicate a SIL deficiency to suffuciently model dependencies. They never arise from user-level escapes.
+  /// PointerEscape  operands indicate a SIL deficiency to sufficiently model dependencies. They never arise from user-level escapes.
   case pointerEscape
   
   /// Bitwise escape. Escapes the nontrivial contents of the value. OSSA does not enforce the lifetime of the escaping bits. The programmer must explicitly force lifetime extension. (ref_to_unowned, unchecked_trivial_bitcast)
diff --git a/SwiftCompilerSources/Sources/SIL/Registration.swift b/SwiftCompilerSources/Sources/SIL/Registration.swift
index 3a6b1c7c73960..25cdfcab10060 100644
--- a/SwiftCompilerSources/Sources/SIL/Registration.swift
+++ b/SwiftCompilerSources/Sources/SIL/Registration.swift
@@ -13,6 +13,11 @@
 import Basic
 import SILBridging
 
+public func registerSIL() {
+  registerSILClasses()
+  registerUtilities()
+}
+
 private func register<T: AnyObject>(_ cl: T.Type) {
   "\(cl)"._withBridgedStringRef { nameStr in
     let metatype = unsafeBitCast(cl, to: SwiftMetatype.self)
@@ -20,7 +25,7 @@ private func register<T: AnyObject>(_ cl: T.Type) {
   }
 }
 
-public func registerSILClasses() {
+private func registerSILClasses() {
   Function.register()
   register(BasicBlock.self)
   register(GlobalVariable.self)
@@ -38,7 +43,6 @@ public func registerSILClasses() {
   register(StoreUnownedInst.self)
   register(StoreBorrowInst.self)
   register(AssignInst.self)
-  register(AssignByWrapperInst.self)
   register(AssignOrInitInst.self)
   register(CopyAddrInst.self)
   register(ExplicitCopyAddrInst.self)
@@ -118,6 +122,7 @@ public func registerSILClasses() {
   register(MoveOnlyWrapperToCopyableAddrInst.self)
   register(ObjectInst.self)
   register(VectorInst.self)
+  register(VectorBaseAddrInst.self)
   register(TuplePackExtractInst.self)
   register(TuplePackElementAddrInst.self)
   register(PackElementGetInst.self)
@@ -215,6 +220,7 @@ public func registerSILClasses() {
   register(MoveValueInst.self)
   register(DropDeinitInst.self)
   register(EndCOWMutationInst.self)
+  register(EndCOWMutationAddrInst.self)
   register(ClassifyBridgeObjectInst.self)
   register(PartialApplyInst.self)
   register(ApplyInst.self)
@@ -260,3 +266,8 @@ public func registerSILClasses() {
   register(MergeIsolationRegionInst.self)
   register(IgnoredUseInst.self)
 }
+
+private func registerUtilities() {
+  registerVerifier()
+  registerPhiUpdater()
+}
diff --git a/SwiftCompilerSources/Sources/SIL/Type.swift b/SwiftCompilerSources/Sources/SIL/Type.swift
index 9ff1526276dcc..ea1767fccb7b7 100644
--- a/SwiftCompilerSources/Sources/SIL/Type.swift
+++ b/SwiftCompilerSources/Sources/SIL/Type.swift
@@ -78,7 +78,13 @@ public struct Type : TypeProperties, CustomStringConvertible, NoReflectionChildr
     !isNoEscapeFunction && isEscapable(in: function)
   }
 
-  public var builtinVectorElementType: Type { canonicalType.builtinVectorElementType.silType! }
+  public func builtinVectorElementType(in function: Function) -> Type {
+    canonicalType.builtinVectorElementType.loweredType(in: function)
+  }
+
+  public func builtinFixedArrayElementType(in function: Function, maximallyAbstracted: Bool = false) -> Type {
+    canonicalType.builtinFixedArrayElementType.loweredType(in: function, maximallyAbstracted: maximallyAbstracted)
+  }
 
   public var superClassType: Type? { canonicalType.superClassType?.silType }
 
@@ -97,6 +103,16 @@ public struct Type : TypeProperties, CustomStringConvertible, NoReflectionChildr
     bridged.isAddressableForDeps(function.bridged)
   }
 
+  /// If this is a raw layout type, returns the substituted like-type.
+  public var rawLayoutSubstitutedLikeType: AST.`Type`? {
+    .init(bridgedOrNil: bridged.getRawLayoutSubstitutedLikeType())
+  }
+
+  /// If this is a raw layout type, returns the substituted count-type.
+  public var rawLayoutSubstitutedCountType: AST.`Type`? {
+    .init(bridgedOrNil: bridged.getRawLayoutSubstitutedCountType())
+  }
+
   //===--------------------------------------------------------------------===//
   //                Properties of lowered `SILFunctionType`s
   //===--------------------------------------------------------------------===//
@@ -108,6 +124,21 @@ public struct Type : TypeProperties, CustomStringConvertible, NoReflectionChildr
     bridged.getFunctionTypeWithNoEscape(withNoEscape).type
   }
 
+  /// True if a function with this type can be code-generated in Embedded Swift.
+  /// These are basically all non-generic functions. But also certain generic functions are supported:
+  /// Generic function arguments which have a class-bound type are valid in Embedded Swift, because for
+  /// such arguments, no metadata is needed, except the isa-pointer of the class.
+  public var hasValidSignatureForEmbedded: Bool {
+    let genericSignature = invocationGenericSignatureOfFunction
+    for genParam in genericSignature.genericParameters {
+      let mappedParam = genericSignature.mapTypeIntoContext(genParam)
+      if mappedParam.isArchetype && !mappedParam.archetypeRequiresClass {
+        return false
+      }
+    }
+    return true
+  }
+
   //===--------------------------------------------------------------------===//
   //                           Aggregates
   //===--------------------------------------------------------------------===//
@@ -125,12 +156,20 @@ public struct Type : TypeProperties, CustomStringConvertible, NoReflectionChildr
     return TupleElementArray(type: self)
   }
 
+  public func getBoxFields(in function: Function) -> BoxFieldsArray {
+    precondition(isBox)
+    return BoxFieldsArray(boxType: canonicalType, function: function)
+  }
+
   /// Returns nil if the nominal is a resilient type because in this case the complete list
   /// of fields is not known.
   public func getNominalFields(in function: Function) -> NominalFieldsArray? {
     guard let nominal = nominal, !nominal.isResilient(in: function) else {
       return nil
     }
+    if let structDecl = nominal as? StructDecl, structDecl.hasUnreferenceableStorage {
+      return nil
+    }
     return NominalFieldsArray(type: self, function: function)
   }
 
@@ -267,6 +306,28 @@ public struct TupleElementArray : RandomAccessCollection, FormattedLikeArray {
   }
 }
 
+public struct BoxFieldsArray : RandomAccessCollection, FormattedLikeArray {
+  public let boxType: CanonicalType
+  public let function: Function
+
+  public var startIndex: Int { return 0 }
+  public var endIndex: Int { BridgedType.getNumBoxFields(boxType.bridged) }
+
+  public subscript(_ index: Int) -> Type {
+    BridgedType.getBoxFieldType(boxType.bridged, index, function.bridged).type
+  }
+
+  public func isMutable(fieldIndex: Int) -> Bool {
+    BridgedType.getBoxFieldIsMutable(boxType.bridged, fieldIndex)
+  }
+}
+
+extension Type: DiagnosticArgument {
+  public func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
+    rawType._withBridgedDiagnosticArgument(fn)
+  }
+}
+
 extension BridgedType {
   public var type: Type { Type(bridged: self) }
   var typeOrNil: Type? { isNull() ? nil : type }
diff --git a/SwiftCompilerSources/Sources/SIL/Utilities/AccessUtils.swift b/SwiftCompilerSources/Sources/SIL/Utilities/AccessUtils.swift
index d7680d9e832f5..e2c489693e50f 100644
--- a/SwiftCompilerSources/Sources/SIL/Utilities/AccessUtils.swift
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/AccessUtils.swift
@@ -89,6 +89,8 @@ public enum AccessBase : CustomStringConvertible, Hashable {
 
   /// The access base is some SIL pattern which does not fit into any other case.
   /// This should be a very rare situation.
+  ///
+  /// TODO: unidentified should preserve its base address value, but AccessBase must be Hashable.
   case unidentified
 
   public init(baseAddress: Value) {
@@ -118,7 +120,7 @@ public enum AccessBase : CustomStringConvertible, Hashable {
     }
   }
 
-  /// Return 'nil' for global varabiables and unidentified addresses.
+  /// Return 'nil' for global variables and unidentified addresses.
   public var address: Value? {
     switch self {
       case .global, .unidentified: return nil
@@ -221,6 +223,21 @@ public enum AccessBase : CustomStringConvertible, Hashable {
     }
   }
 
+  public var storageIsLexical: Bool {
+    switch self {
+    case .argument(let arg):
+      return arg.isLexical
+    case .stack(let allocStack):
+      return allocStack.isLexical
+    case .global:
+      return true
+    case .box, .class, .tail:
+      return reference!.referenceRoot.isLexical
+    case .yield, .pointer, .index, .storeBorrow, .unidentified:
+      return false
+    }
+  }
+
   /// Returns true if it's guaranteed that this access has the same base address as the `other` access.
   ///
   /// `isEqual` abstracts away the projection instructions that are included as part of the AccessBase:
@@ -306,8 +323,19 @@ public enum AccessBase : CustomStringConvertible, Hashable {
              isDifferentAllocation(rea.instance, otherRea.instance) ||
              hasDifferentType(rea.instance, otherRea.instance)
     case (.tail(let rta), .tail(let otherRta)):
-      return isDifferentAllocation(rta.instance, otherRta.instance) ||
-             hasDifferentType(rta.instance, otherRta.instance)
+      if isDifferentAllocation(rta.instance, otherRta.instance) {
+        return true
+      }
+      if hasDifferentType(rta.instance, otherRta.instance),
+         // In contrast to `ref_element_addr`, tail addresses can also be obtained via a superclass
+         // (in case the derived class doesn't add any stored properties).
+         // Therefore if the instance types differ by sub-superclass relationship, the base is _not_ different.
+         !rta.instance.type.isExactSuperclass(of: otherRta.instance.type),
+         !otherRta.instance.type.isExactSuperclass(of: rta.instance.type)
+      {
+        return true
+      }
+      return false
     case (.argument(let arg), .argument(let otherArg)):
       return (arg.convention.isExclusiveIndirect || otherArg.convention.isExclusiveIndirect) && arg != otherArg
       
@@ -375,6 +403,11 @@ public struct AccessPath : CustomStringConvertible, Hashable {
   public func isEqualOrContains(_ other: AccessPath) -> Bool {
     return getProjection(to: other) != nil
   }
+  
+  /// Returns true if this access contains `other` access and is not equal.
+  public func contains(_ other: AccessPath) -> Bool {
+    return !(getProjection(to: other)?.isEmpty ?? true)
+  }
 
   public var materializableProjectionPath: SmallProjectionPath? {
     if projectionPath.isMaterializable {
@@ -414,7 +447,7 @@ public struct AccessPath : CustomStringConvertible, Hashable {
 
 private func canBeOperandOfIndexAddr(_ value: Value) -> Bool {
   switch value {
-  case is IndexAddrInst, is RefTailAddrInst, is PointerToAddressInst:
+  case is IndexAddrInst, is RefTailAddrInst, is PointerToAddressInst, is VectorBaseAddrInst:
     return true
   default:
     return false
@@ -556,10 +589,6 @@ public struct AccessBaseAndScopes {
     self.scopes = scopes
   }
 
-  public var outerAddress: Value? {
-    base.address ?? scopes.last?.address
-  }
-
   public var enclosingAccess: EnclosingAccessScope {
     return scopes.first ?? .base(base)
   }
@@ -733,7 +762,7 @@ extension Value {
   // Although an AccessPathWalker is created for each call of these properties,
   // it's very unlikely that this will end up in memory allocations.
   // Only in the rare case of `pointer_to_address` -> `address_to_pointer` pairs, which
-  // go through phi-arguments, the AccessPathWalker will allocate memnory in its cache.
+  // go through phi-arguments, the AccessPathWalker will allocate memory in its cache.
 
   /// Computes the access base of this address value.
   public var accessBase: AccessBase { accessPath.base }
@@ -857,3 +886,11 @@ extension Function {
     return nil
   }
 }
+
+let getAccessBaseTest = Test("swift_get_access_base") {
+  function, arguments, context in
+  let address = arguments.takeValue()
+  print("Address: \(address)")
+  let base = address.accessBase
+  print("Base: \(base)")
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/BorrowUtils.swift b/SwiftCompilerSources/Sources/SIL/Utilities/BorrowUtils.swift
similarity index 89%
rename from SwiftCompilerSources/Sources/Optimizer/Utilities/BorrowUtils.swift
rename to SwiftCompilerSources/Sources/SIL/Utilities/BorrowUtils.swift
index 2aa2343f36aff..187dc228c153b 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/BorrowUtils.swift
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/BorrowUtils.swift
@@ -130,8 +130,6 @@
 // patterns).
 // ===----------------------------------------------------------------------===//
 
-import SIL
-
 /// A scoped instruction that borrows one or more operands.
 ///
 /// If this instruction produces a borrowed value, then BeginBorrowValue(resultOf: self) != nil.
@@ -151,7 +149,7 @@ import SIL
 /// operand.
 ///
 /// TODO: replace BorrowIntroducingInstruction with this.
-enum BorrowingInstruction : CustomStringConvertible, Hashable {
+public enum BorrowingInstruction : CustomStringConvertible, Hashable {
   case beginBorrow(BeginBorrowInst)
   case borrowedFrom(BorrowedFromInst)
   case storeBorrow(StoreBorrowInst)
@@ -160,7 +158,7 @@ enum BorrowingInstruction : CustomStringConvertible, Hashable {
   case markDependence(MarkDependenceInst)
   case startAsyncLet(BuiltinInst)
 
-  init?(_ inst: Instruction) {
+  public init?(_ inst: Instruction) {
     switch inst {
     case let bbi as BeginBorrowInst:
       self = .beginBorrow(bbi)
@@ -185,7 +183,7 @@ enum BorrowingInstruction : CustomStringConvertible, Hashable {
     }
   }
   
-  var instruction: Instruction {
+  public var instruction: Instruction {
     switch self {
     case .beginBorrow(let bbi):
       return bbi
@@ -204,14 +202,17 @@ enum BorrowingInstruction : CustomStringConvertible, Hashable {
     }
   }
 
-  var innerValue: Value? {
+  public var innerValue: Value? {
     if let dependent = dependentValue {
       return dependent
     }
     return scopedValue
   }
 
-  var dependentValue: Value? {
+  /// Returns non-nil if this borrowing instruction produces an guaranteed dependent value and does not have immediate
+  /// scope-ending uses. Finding the borrow scope in such cases requires recursively following uses of the guaranteed
+  /// value.
+  public var dependentValue: Value? {
     switch self {
     case .borrowedFrom(let bfi):
       let phi = bfi.borrowedPhi
@@ -230,7 +231,7 @@ enum BorrowingInstruction : CustomStringConvertible, Hashable {
   }
 
   /// If this is valid, then visitScopeEndingOperands succeeds.
-  var scopedValue: Value? {
+  public var scopedValue: Value? {
     switch self {
     case .beginBorrow, .storeBorrow:
       return instruction as! SingleValueInstruction
@@ -268,7 +269,7 @@ enum BorrowingInstruction : CustomStringConvertible, Hashable {
   ///
   /// TODO: For instructions that are not a BeginBorrowValue, verify that scope ending instructions exist on all
   /// paths. These instructions should be complete after SILGen and never cloned to produce phis.
-  func visitScopeEndingOperands(_ context: Context, visitor: @escaping (Operand) -> WalkResult) -> WalkResult {
+  public func visitScopeEndingOperands(_ context: Context, visitor: @escaping (Operand) -> WalkResult) -> WalkResult {
     guard let val = scopedValue else {
       return .abortWalk
     }
@@ -299,7 +300,7 @@ enum BorrowingInstruction : CustomStringConvertible, Hashable {
 extension BorrowingInstruction {
   private func visitEndBorrows(value: Value, _ context: Context, _ visitor: @escaping (Operand) -> WalkResult)
     -> WalkResult {
-    return value.lookThroughBorrowedFromUser.uses.filterUsers(ofType: EndBorrowInst.self).walk {
+    return value.lookThroughBorrowedFromUser.uses.filterUses(ofType: EndBorrowInst.self).walk {
       visitor($0)
     }
   }
@@ -323,7 +324,7 @@ extension BorrowingInstruction {
     }
   }
 
-  var description: String { instruction.description }
+  public var description: String { instruction.description }
 }
 
 /// A value that introduces a borrow scope:
@@ -337,7 +338,7 @@ extension BorrowingInstruction {
 /// one of the yielded values. In any case, the scope ending operands
 /// are on the end_apply or abort_apply instructions that use the
 /// token.
-enum BeginBorrowValue {
+public enum BeginBorrowValue {
   case beginBorrow(BeginBorrowInst)
   case loadBorrow(LoadBorrowInst)
   case beginApply(Value)
@@ -345,7 +346,7 @@ enum BeginBorrowValue {
   case functionArgument(FunctionArgument)
   case reborrow(Phi)
 
-  init?(_ value: Value) {
+  public init?(_ value: Value) {
     switch value {
     case let bbi as BeginBorrowInst:
       self = .beginBorrow(bbi)
@@ -366,7 +367,7 @@ enum BeginBorrowValue {
     }
   }
   
-  var value: Value {
+  public var value: Value {
     switch self {
     case .beginBorrow(let bbi): return bbi
     case .loadBorrow(let lbi): return lbi
@@ -377,7 +378,7 @@ enum BeginBorrowValue {
     }
   }
 
-  init?(using operand: Operand) {
+  public init?(using operand: Operand) {
     switch operand.instruction {
     case is BeginBorrowInst, is LoadBorrowInst:
       let inst = operand.instruction as! SingleValueInstruction
@@ -395,7 +396,7 @@ enum BeginBorrowValue {
     }
   }
 
-  init?(resultOf borrowInstruction: BorrowingInstruction) {
+  public init?(resultOf borrowInstruction: BorrowingInstruction) {
     switch borrowInstruction {
     case let .beginBorrow(beginBorrow):
       self.init(beginBorrow)
@@ -409,7 +410,7 @@ enum BeginBorrowValue {
     }
   }
 
-  var hasLocalScope: Bool {
+  public var hasLocalScope: Bool {
     switch self {
     case .beginBorrow, .loadBorrow, .beginApply, .reborrow, .uncheckOwnershipConversion:
       return true
@@ -422,10 +423,10 @@ enum BeginBorrowValue {
   // load_borrow.
   //
   // Return nil for begin_apply and reborrow, which need special handling.
-  var baseOperand: Operand? {
+  public var baseOperand: Operand? {
     switch self {
     case let .beginBorrow(beginBorrow):
-    return beginBorrow.operand
+      return beginBorrow.operand
     case let .loadBorrow(loadBorrow):
       return loadBorrow.operand
     case .beginApply, .functionArgument, .reborrow, .uncheckOwnershipConversion:
@@ -435,7 +436,7 @@ enum BeginBorrowValue {
 
   /// The EndBorrows, reborrows (phis), and consumes (of closures)
   /// that end the local borrow scope. Empty if hasLocalScope is false.
-  var scopeEndingOperands: LazyFilterSequence<UseList> {
+  public var scopeEndingOperands: LazyFilterSequence<UseList> {
     switch self {
     case let .beginApply(value):
       return (value.definingInstruction
@@ -448,28 +449,8 @@ enum BeginBorrowValue {
   }
 }
 
-/// Compute the live range for the borrow scopes of a guaranteed value. This returns a separate instruction range for
-/// each of the value's borrow introducers.
-///
-/// TODO: This should return a single multiply-defined instruction range.
-func computeBorrowLiveRange(for value: Value, _ context: FunctionPassContext)
-  -> SingleInlineArray<(BeginBorrowValue, InstructionRange)> {
-  assert(value.ownership == .guaranteed)
-
-  var ranges = SingleInlineArray<(BeginBorrowValue, InstructionRange)>()
-  // If introducers is empty, then the dependence is on a trivial value, so
-  // there is no ownership range.
-  for beginBorrow in value.getBorrowIntroducers(context) {
-    /// FIXME: Remove calls to computeKnownLiveness() as soon as lifetime completion runs immediately after
-    /// SILGen. Instead, this should compute linear liveness for borrowed value by switching over BeginBorrowValue, just
-    /// like LifetimeDependenc.Scope.computeRange().
-    ranges.push((beginBorrow, computeKnownLiveness(for: beginBorrow.value, context)))
-  }
-  return ranges
-}
-
 extension Value {
-  var lookThroughBorrowedFrom: Value {
+  public var lookThroughBorrowedFrom: Value {
     if let bfi = self as? BorrowedFromInst {
       return bfi.borrowedValue.lookThroughBorrowedFrom
     }
@@ -477,20 +458,20 @@ extension Value {
   }
 }
 
-struct BorrowIntroducers<Ctxt: Context> : CollectionLikeSequence {
+public struct BorrowIntroducers<Ctxt: Context> : CollectionLikeSequence {
   let initialValue: Value
   let context: Ctxt
 
-  func makeIterator() -> EnclosingValueIterator {
+  public func makeIterator() -> EnclosingValueIterator {
     EnclosingValueIterator(forBorrowIntroducers: initialValue, context)
   }
 }
 
-struct EnclosingValues<Ctxt: Context> : CollectionLikeSequence {
+public struct EnclosingValues<Ctxt: Context> : CollectionLikeSequence {
   let initialValue: Value
   let context: Ctxt
 
-  func makeIterator() -> EnclosingValueIterator {
+  public func makeIterator() -> EnclosingValueIterator {
     EnclosingValueIterator(forEnclosingValues: initialValue, context)
   }
 }
@@ -498,7 +479,7 @@ struct EnclosingValues<Ctxt: Context> : CollectionLikeSequence {
 // This iterator must be a class because we need a deinit.
 // It shouldn't be a performance problem because the optimizer should always be able to stack promote the iterator.
 // TODO: Make it a struct once this is possible with non-copyable types.
-final class EnclosingValueIterator : IteratorProtocol {
+public final class EnclosingValueIterator : IteratorProtocol {
   var worklist: ValueWorklist
 
   init(forBorrowIntroducers value: Value, _ context: some Context) {
@@ -532,7 +513,7 @@ final class EnclosingValueIterator : IteratorProtocol {
     worklist.deinitialize()
   }
 
-  func next() -> Value? {
+  public func next() -> Value? {
     while let value = worklist.pop() {
       switch value.ownership {
       case .none, .unowned:
@@ -553,7 +534,10 @@ final class EnclosingValueIterator : IteratorProtocol {
         } else if let forwardingInst = value.forwardingInstruction {
           // Recurse through guaranteed forwarding non-phi instructions.
           let ops = forwardingInst.forwardedOperands
-          worklist.pushIfNotVisited(contentsOf: ops.lazy.map { $0.value })
+          worklist.pushIfNotVisited(contentsOf: ops.values)
+        } else if value.isGuaranteedApplyResult {
+          let selfArgument = (value as! ApplyInst).arguments.last!
+          worklist.pushIfNotVisited(selfArgument)
         } else {
           fatalError("cannot get borrow introducers for unknown guaranteed value")
         }
@@ -581,7 +565,9 @@ extension Value {
   ///     %field = ref_element_addr %first           // (none)
   ///     %load = load_borrow %field : $*C           // %load
   ///
-  func getBorrowIntroducers<Ctxt: Context>(_ context: Ctxt) -> LazyMapSequence<BorrowIntroducers<Ctxt>, BeginBorrowValue> {
+  public func getBorrowIntroducers<Ctxt: Context>(
+    _ context: Ctxt
+  ) -> LazyMapSequence<BorrowIntroducers<Ctxt>, BeginBorrowValue> {
     BorrowIntroducers(initialValue: self, context: context).lazy.map { BeginBorrowValue($0)! }
   }
 
@@ -622,15 +608,37 @@ extension Value {
   ///   bb1(%outerReborrow : @reborrow,              // %0
   ///       %innerReborrow : @reborrow)              // %outerReborrow
   ///
-  func getEnclosingValues<Ctxt: Context>(_ context: Ctxt) -> EnclosingValues<Ctxt> {
+  public func getEnclosingValues<Ctxt: Context>(_ context: Ctxt) -> EnclosingValues<Ctxt> {
     EnclosingValues(initialValue: self, context: context)
   }
+
+  public var lookThroughBorrowedFromUser: Value {
+    for use in uses {
+      if let bfi = use.forwardingBorrowedFromUser {
+        return bfi
+      }
+    }
+    return self
+  }
+
+  public var isGuaranteedApplyResult: Bool {
+    guard let definingInstruction = self.definingInstruction else {
+      return false
+    }
+    guard let apply = definingInstruction as? ApplyInst else {
+      return false
+    }
+    guard apply.singleDirectResult != nil else {
+      return false
+    }
+    return apply.functionConvention.results[0].convention == .guaranteed
+  }
 }
 
 extension Phi {
   /// The inner adjacent phis of this outer "enclosing" phi.
   /// These keep the enclosing (outer adjacent) phi alive.
-  var innerAdjacentPhis: LazyMapSequence<LazyFilterSequence<LazyMapSequence<UseList, Phi?>>, Phi> {
+  public var innerAdjacentPhis: LazyMapSequence<LazyFilterSequence<LazyMapSequence<UseList, Phi?>>, Phi> {
     value.uses.lazy.compactMap { use in
       if let bfi = use.instruction as? BorrowedFromInst,
          use.index != 0
@@ -644,7 +652,7 @@ extension Phi {
 
 /// Gathers enclosing values by visiting predecessor blocks.
 /// Only used for updating borrowed-from instructions and for verification.
-func gatherEnclosingValuesFromPredecessors(
+public func gatherEnclosingValuesFromPredecessors(
   for phi: Phi,
   in enclosingValues: inout Stack<Value>,
   _ context: some Context
@@ -666,7 +674,7 @@ func gatherEnclosingValuesFromPredecessors(
 
 extension BasicBlock {
   // Returns either the `incomingEnclosingValue` or an adjacent phi in the successor block.
-  func getEnclosingValueInSuccessor(ofIncoming incomingEnclosingValue: Value) -> Value {
+  public func getEnclosingValueInSuccessor(ofIncoming incomingEnclosingValue: Value) -> Value {
     let branch = terminator as! BranchInst
     if let incomingEV = branch.operands.first(where: { branchOp in
       // Only if the lifetime of `branchOp` ends at the branch (either because it's a reborrow or an owned value),
@@ -694,7 +702,7 @@ extension BasicBlock {
   }
 }
 
-let borrowIntroducersTest = FunctionTest("borrow_introducers") {
+let borrowIntroducersTest = Test("borrow_introducers") {
   function, arguments, context in
   let value = arguments.takeValue()
   print(function)
@@ -704,7 +712,7 @@ let borrowIntroducersTest = FunctionTest("borrow_introducers") {
   }
 }
 
-let enclosingValuesTest = FunctionTest("enclosing_values") {
+let enclosingValuesTest = Test("enclosing_values") {
   function, arguments, context in
   let value = arguments.takeValue()
   print(function)
@@ -718,14 +726,3 @@ let enclosingValuesTest = FunctionTest("enclosing_values") {
   }
 }
 
-extension Value {
-  var lookThroughBorrowedFromUser: Value {
-    for use in uses {
-      if let bfi = use.forwardingBorrowedFromUser {
-        return bfi
-      }
-    }
-    return self
-  }
-}
-
diff --git a/SwiftCompilerSources/Sources/SIL/Utilities/CMakeLists.txt b/SwiftCompilerSources/Sources/SIL/Utilities/CMakeLists.txt
index ef985c9c68ab4..59ba3af5f8912 100644
--- a/SwiftCompilerSources/Sources/SIL/Utilities/CMakeLists.txt
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/CMakeLists.txt
@@ -8,8 +8,15 @@
 
 swift_compiler_sources(SIL
   AccessUtils.swift
+  BorrowUtils.swift
+  Cloner.swift
+  ForwardingUtils.swift
+  PhiUpdater.swift
   SequenceUtilities.swift
   SmallProjectionPath.swift
+  SSAUpdater.swift
+  Test.swift
   WalkUtils.swift
+  Verifier.swift
 )
 
diff --git a/SwiftCompilerSources/Sources/SIL/Utilities/Cloner.swift b/SwiftCompilerSources/Sources/SIL/Utilities/Cloner.swift
new file mode 100644
index 0000000000000..e010a16642048
--- /dev/null
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/Cloner.swift
@@ -0,0 +1,197 @@
+//===--- Cloner.swift ------------------------------------------------------==//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SILBridging
+import AST
+
+/// Clones the initializer value of a GlobalVariable.
+///
+/// Used to transitively clone "constant" instructions, including their operands,
+/// from or to the static initializer value of a GlobalVariable.
+///
+public struct Cloner<Context: MutatingContext> {
+  private var bridged: BridgedCloner
+  public let context: Context
+
+  public enum GetClonedResult {
+    case defaultValue
+    case customValue(Value)
+    case stopCloning
+  }
+  
+  public enum Target {
+    case function(Function)
+    case global(GlobalVariable)
+  }
+  public let target: Target
+
+  public init(cloneToGlobal: GlobalVariable, _ context: Context) {
+    self.bridged = BridgedCloner(cloneToGlobal.bridged, context._bridged)
+    self.context = context
+    self.target = .global(cloneToGlobal)
+  }
+
+  public init(cloneBefore inst: Instruction, _ context: Context) {
+    self.bridged = BridgedCloner(inst.bridged, context._bridged)
+    self.context = context
+    self.target = .function(inst.parentFunction)
+  }
+
+  public init(cloneToEmptyFunction: Function, _ context: Context) {
+    self.bridged = BridgedCloner(cloneToEmptyFunction.bridged, context._bridged)
+    self.context = context
+    self.target = .function(cloneToEmptyFunction)
+  }
+
+  public mutating func deinitialize() {
+    bridged.destroy(context._bridged)
+  }
+
+  public var targetFunction: Function {
+    guard case .function(let function) = target else {
+      fatalError("expected cloning into a function")
+    }
+    return function
+  }
+
+  public func getOrCreateEntryBlock() -> BasicBlock {
+    if let entryBlock = targetFunction.blocks.first {
+      return entryBlock
+    }
+    let entryBlock = targetFunction.appendNewBlock(context)
+    bridged.setInsertionBlockIfNotSet(entryBlock.bridged)
+    return entryBlock
+  }
+
+  public func cloneFunctionBody(from originalFunction: Function, entryBlockArguments: [Value]) {
+    entryBlockArguments.withBridgedValues { bridgedEntryBlockArgs in
+      let entryBlock = getOrCreateEntryBlock()
+      bridged.cloneFunctionBody(originalFunction.bridged, entryBlock.bridged, bridgedEntryBlockArgs)
+    }
+  }
+
+  public func cloneFunctionBody(from originalFunction: Function) {
+    bridged.cloneFunctionBody(originalFunction.bridged)
+  }
+
+  public mutating func clone(instruction: Instruction) -> Instruction {
+    let cloned = bridged.clone(instruction.bridged).instruction
+    if case .function = target {
+      context.notifyInstructionChanged(cloned)
+      context.notifyInstructionsChanged()
+    }
+    return cloned
+  }
+  
+  public mutating func cloneRecursively(globalInitValue: Value) -> Value {
+    guard let cloned = cloneRecursively(value: globalInitValue, customGetCloned: { value, cloner in
+      guard let beginAccess = value as? BeginAccessInst else {
+        return .defaultValue
+      }
+      
+      // Skip access instructions, which might be generated for UnsafePointer globals which point to other globals.
+      let clonedOperand = cloner.cloneRecursively(globalInitValue: beginAccess.address)
+      cloner.recordFoldedValue(beginAccess, mappedTo: clonedOperand)
+      return .customValue(clonedOperand)
+    }) else {
+      fatalError("Clone recursively to global shouldn't bail.")
+    }
+    
+    return cloned
+  }
+
+  /// Transitively clones `value` including its defining instruction's operands.
+  public mutating func cloneRecursively( value: Value) -> Value {
+    return cloneRecursively(value: value, customGetCloned: { _, _ in .defaultValue })!
+  }
+
+  /// Transitively clones `value` including its defining instruction's operands.
+  public mutating func cloneRecursively(value: Value, customGetCloned: (Value, inout Cloner) -> GetClonedResult) -> Value? {
+    if isCloned(value: value) {
+      return getClonedValue(of: value)
+    }
+    
+    switch customGetCloned(value, &self) {
+    case .customValue(let base):
+      return base
+    case .stopCloning:
+      return nil
+    case .defaultValue:
+      break
+    }
+
+    guard let inst = value.definingInstruction else {
+      fatalError("expected instruction to clone or already cloned value")
+    }
+
+    for op in inst.operands {
+      if cloneRecursively(value: op.value, customGetCloned: customGetCloned) == nil {
+        return nil
+      }
+    }
+
+    let cloned = clone(instruction: inst)
+    if let svi = cloned as? SingleValueInstruction {
+      return svi
+    } else if let originalMvi = value as? MultipleValueInstructionResult {
+      return cloned.results[originalMvi.index]
+    }
+    fatalError("unexpected instruction kind")
+  }
+
+  public mutating func getClonedValue(of originalValue: Value) -> Value {
+    bridged.getClonedValue(originalValue.bridged).value
+  }
+
+  public func isCloned(value: Value) -> Bool {
+    bridged.isValueCloned(value.bridged)
+  }
+
+  public func getClonedBlock(for originalBlock: BasicBlock) -> BasicBlock {
+    bridged.getClonedBasicBlock(originalBlock.bridged).block
+  }
+
+  public func recordFoldedValue(_ origValue: Value, mappedTo mappedValue: Value) {
+    bridged.recordFoldedValue(origValue.bridged, mappedValue.bridged)
+  }
+}
+
+public struct TypeSubstitutionCloner<Context: MutatingContext> {
+  public private(set) var bridged: BridgedTypeSubstCloner
+  public let context: Context
+
+  public init(fromFunction: Function,
+              toEmptyFunction: Function,
+              substitutions: SubstitutionMap, _ context: Context
+  ) {
+    context.verifyIsTransforming(function: toEmptyFunction)
+    self.bridged = BridgedTypeSubstCloner(fromFunction.bridged, toEmptyFunction.bridged,
+                                          substitutions.bridged, context._bridged)
+    self.context = context
+  }
+
+  public mutating func deinitialize() {
+    bridged.destroy(context._bridged)
+  }
+
+  public mutating func getClonedValue(of originalValue: Value) -> Value {
+    bridged.getClonedValue(originalValue.bridged).value
+  }
+
+  public func getClonedBlock(for originalBlock: BasicBlock) -> BasicBlock {
+    bridged.getClonedBasicBlock(originalBlock.bridged).block
+  }
+
+  public func cloneFunctionBody() {
+    bridged.cloneFunctionBody()
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/ForwardingUtils.swift b/SwiftCompilerSources/Sources/SIL/Utilities/ForwardingUtils.swift
similarity index 86%
rename from SwiftCompilerSources/Sources/Optimizer/Utilities/ForwardingUtils.swift
rename to SwiftCompilerSources/Sources/SIL/Utilities/ForwardingUtils.swift
index 56122160a64c8..03b0e3b422830 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/ForwardingUtils.swift
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/ForwardingUtils.swift
@@ -16,8 +16,6 @@
 /// is part of a forward-extended lifetime that has a pointer escape.
 //===----------------------------------------------------------------------===//
 
-import SIL
-
 private let verbose = false
 
 private func log(_ message: @autoclosure () -> String) {
@@ -36,7 +34,7 @@ private func log(_ message: @autoclosure () -> String) {
 /// Allocation. Then add a `Value.hasPointerEscapingUse` property that
 /// performs the use-def walk to pickup the flags. Then only call into
 /// this def-use walk to initially set the flags.
-func findPointerEscapingUse(of value: Value) -> Bool {
+public func findPointerEscapingUse(of value: Value) -> Bool {
   value.bridged.findPointerEscape()
 }
 
@@ -100,7 +98,7 @@ func findPointerEscapingUse(of value: Value) -> Bool {
 /// This walker is used to query basic lifetime attributes on values,
 /// such as "escaping" or "lexical". It must be precise for
 /// correctness and is performance critical.
-protocol ForwardingUseDefWalker {
+public protocol ForwardingUseDefWalker {
   associatedtype PathContext
 
   mutating func introducer(_ value: Value, _ path: PathContext) -> WalkResult
@@ -113,12 +111,12 @@ protocol ForwardingUseDefWalker {
 }
 
 extension ForwardingUseDefWalker {
-  mutating func walkUp(value: Value, _ path: PathContext) -> WalkResult {
+  public mutating func walkUp(value: Value, _ path: PathContext) -> WalkResult {
     walkUpDefault(forwarded: value, path)
   }
-  mutating func walkUpDefault(forwarded value: Value, _ path: PathContext)
+  public mutating func walkUpDefault(forwarded value: Value, _ path: PathContext)
     -> WalkResult {
-    if let inst = value.forwardingInstruction {
+    if let inst = value.forwardingInstruction, !inst.forwardedOperands.isEmpty {
       return walkUp(instruction: inst, path)
     }
     if let phi = Phi(value) {
@@ -126,7 +124,7 @@ extension ForwardingUseDefWalker {
     }
     return introducer(value, path)
   }
-  mutating func walkUp(instruction: ForwardingInstruction, _ path: PathContext)
+  public mutating func walkUp(instruction: ForwardingInstruction, _ path: PathContext)
     -> WalkResult {
     for operand in instruction.forwardedOperands {
       if needWalk(for: operand.value, path) {
@@ -137,7 +135,7 @@ extension ForwardingUseDefWalker {
     }
     return .continueWalk
   }
-  mutating func walkUp(phi: Phi, _ path: PathContext) -> WalkResult {
+  public mutating func walkUp(phi: Phi, _ path: PathContext) -> WalkResult {
     for operand in phi.incomingOperands {
       if needWalk(for: operand.value, path) {
         if walkUp(value: operand.value, path) == .abortWalk {
@@ -151,7 +149,7 @@ extension ForwardingUseDefWalker {
 
 // This conveniently gathers all forward introducers and deinitializes
 // visitedValues before the caller has a chance to recurse.
-func gatherLifetimeIntroducers(for value: Value, _ context: Context) -> [Value] {
+public func gatherLifetimeIntroducers(for value: Value, _ context: Context) -> [Value] {
   var introducers: [Value] = []
   var walker = VisitLifetimeIntroducers(context) {
     introducers.append($0)
@@ -163,8 +161,8 @@ func gatherLifetimeIntroducers(for value: Value, _ context: Context) -> [Value]
 }
 
 // TODO: visitor can be nonescaping when we have borrowed properties.
-func visitLifetimeIntroducers(for value: Value, _ context: Context,
-                              visitor: @escaping (Value) -> WalkResult)
+public func visitLifetimeIntroducers(for value: Value, _ context: Context,
+                                     visitor: @escaping (Value) -> WalkResult)
   -> WalkResult {
   var walker = VisitLifetimeIntroducers(context, visitor: visitor)
   defer { walker.visitedValues.deinitialize() }
@@ -191,11 +189,11 @@ private struct VisitLifetimeIntroducers : ForwardingUseDefWalker {
   }
 }
 
-enum ForwardingUseResult: CustomStringConvertible {
+public enum ForwardingUseResult: CustomStringConvertible {
   case operand(Operand)
   case deadValue(Value, Operand?)
 
-  var description: String {
+  public var description: String {
     switch self {
     case .operand(let operand):
       return operand.description
@@ -220,7 +218,7 @@ enum ForwardingUseResult: CustomStringConvertible {
 /// Start walking:
 ///   walkDown(root: Value)
 ///
-protocol ForwardingDefUseWalker {
+public protocol ForwardingDefUseWalker {
   /// Minimally, check a ValueSet. This walker may traverse chains of
   /// aggregation and destructuring by default. Implementations may
   /// handle phis.
@@ -249,16 +247,16 @@ protocol ForwardingDefUseWalker {
 
 extension ForwardingDefUseWalker {
   /// Start walking
-  mutating func walkDown(root: Value) -> WalkResult {
+  public mutating func walkDown(root: Value) -> WalkResult {
     walkDownUses(of: root, using: nil)
   }
 
-  mutating func walkDownUses(of value: Value, using operand: Operand?)
+  public mutating func walkDownUses(of value: Value, using operand: Operand?)
     -> WalkResult {
     return walkDownUsesDefault(forwarding: value, using: operand)
   }
 
-  mutating func walkDownUsesDefault(forwarding value: Value,
+  public mutating func walkDownUsesDefault(forwarding value: Value,
     using operand: Operand?)
   -> WalkResult {
     if !needWalk(for: value) {
@@ -277,11 +275,11 @@ extension ForwardingDefUseWalker {
     return .continueWalk
   }
 
-  mutating func walkDown(operand: Operand) -> WalkResult {
+  public mutating func walkDown(operand: Operand) -> WalkResult {
     walkDownDefault(forwarding: operand)
   }
 
-  mutating func walkDownDefault(forwarding operand: Operand) -> WalkResult {
+  public mutating func walkDownDefault(forwarding operand: Operand) -> WalkResult {
     if let inst = operand.instruction as? ForwardingInstruction {
       let singleOper = inst.singleForwardedOperand
       if singleOper == nil || singleOper! == operand {
@@ -303,8 +301,8 @@ extension ForwardingDefUseWalker {
 /// gatherLifetimeIntroducers().
 ///
 /// TODO: make the visitor non-escaping once Swift supports stored
-/// non-escaping closues.
-func visitForwardedUses(introducer: Value, _ context: Context,
+/// non-escaping closures.
+public func visitForwardedUses(introducer: Value, _ context: Context,
   visitor: @escaping (ForwardingUseResult) -> WalkResult)
 -> WalkResult {
   var useVisitor = VisitForwardedUses(visitor: visitor, context)
@@ -345,29 +343,29 @@ private struct VisitForwardedUses : ForwardingDefUseWalker {
 /// This is a subset of the functionality in LifetimeDependenceDefUseWalker, but significantly simpler. This avoids
 /// traversing lifetime dependencies that do not propagate context. For example, a mark_dependence on a closure extends
 /// its lifetime but cannot introduce any new uses of the closure context.
-struct NonEscapingClosureDefUseWalker {
+public struct NonEscapingClosureDefUseWalker {
   let context: Context
   var visitedValues: ValueSet
-  var applyOperandStack: Stack<Operand>
+  public var applyOperandStack: Stack<Operand>
 
   /// `visitor` takes an operand whose instruction is always a FullApplySite.
-  init(_ context: Context) {
+  public init(_ context: Context) {
     self.context = context
     self.visitedValues = ValueSet(context)
     self.applyOperandStack = Stack(context)
   }
 
-  mutating func deinitialize() {
+  public mutating func deinitialize() {
     visitedValues.deinitialize()
     applyOperandStack.deinitialize()
   }
 
-  mutating func walkDown(closure: PartialApplyInst) -> WalkResult {
+  public mutating func walkDown(closure: PartialApplyInst) -> WalkResult {
     assert(!closure.mayEscape)
     return walkDownUses(of: closure, using: nil)
   }
 
-  mutating func closureContextLeafUse(of operand: Operand) -> WalkResult {
+  public mutating func closureContextLeafUse(of operand: Operand) -> WalkResult {
     switch operand.instruction {
     case is FullApplySite:
       applyOperandStack.push(operand)
@@ -388,11 +386,11 @@ struct NonEscapingClosureDefUseWalker {
 }
 
 extension NonEscapingClosureDefUseWalker: ForwardingDefUseWalker {
-  mutating func needWalk(for value: Value) -> Bool {
+  public mutating func needWalk(for value: Value) -> Bool {
     visitedValues.insert(value)
   }
 
-  mutating func nonForwardingUse(of operand: Operand) -> WalkResult {
+  public mutating func nonForwardingUse(of operand: Operand) -> WalkResult {
     // Nonescaping closures may be moved, copied, or borrowed.
     switch operand.instruction {
     case let transition as OwnershipTransitionInstruction:
@@ -405,12 +403,12 @@ extension NonEscapingClosureDefUseWalker: ForwardingDefUseWalker {
     }
   }
 
-  mutating func deadValue(_ value: Value, using operand: Operand?) -> WalkResult {
+  public mutating func deadValue(_ value: Value, using operand: Operand?) -> WalkResult {
     return .continueWalk
   }
 }
 
-let forwardingUseDefTest = FunctionTest("forwarding_use_def_test") {
+let forwardingUseDefTest = Test("forwarding_use_def_test") {
   function, arguments, context in
   let value = arguments.takeValue()
   for introducer in gatherLifetimeIntroducers(for: value, context) {
@@ -418,7 +416,7 @@ let forwardingUseDefTest = FunctionTest("forwarding_use_def_test") {
   }
 }
 
-let forwardingDefUseTest = FunctionTest("forwarding_def_use_test") {
+let forwardingDefUseTest = Test("forwarding_def_use_test") {
   function, arguments, context in
   let value = arguments.takeValue()
   _ = visitForwardedUses(introducer: value, context) { useResult in
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/PhiUpdater.swift b/SwiftCompilerSources/Sources/SIL/Utilities/PhiUpdater.swift
similarity index 83%
rename from SwiftCompilerSources/Sources/Optimizer/Utilities/PhiUpdater.swift
rename to SwiftCompilerSources/Sources/SIL/Utilities/PhiUpdater.swift
index 9b0a8ccc803d4..5029a91136a5e 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/PhiUpdater.swift
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/PhiUpdater.swift
@@ -10,23 +10,22 @@
 //
 //===----------------------------------------------------------------------===//
 
-import SIL
-import OptimizerBridging
+import SILBridging
 
 /// Updates the reborrow flags and the borrowed-from instructions for all guaranteed phis in `function`.
-func updateGuaranteedPhis(in function: Function, _ context: some MutatingContext) {
+public func updateGuaranteedPhis(in function: Function, _ context: some MutatingContext) {
   updateReborrowFlags(in: function, context)
   updateBorrowedFrom(in: function, context)
 }
 
 /// Updates the reborrow flags and the borrowed-from instructions for all `phis`.
-func updateGuaranteedPhis(phis: some Sequence<Phi>, _ context: some MutatingContext) {
+public func updateGuaranteedPhis(phis: some Sequence<Phi>, _ context: some MutatingContext) {
   updateReborrowFlags(for: phis, context)
   updateBorrowedFrom(for: phis, context)
 }
 
 /// Update all borrowed-from instructions in the `function`
-func updateBorrowedFrom(in function: Function, _ context: some MutatingContext) {
+public func updateBorrowedFrom(in function: Function, _ context: some MutatingContext) {
   if !function.hasOwnership {
     return
   }
@@ -44,7 +43,7 @@ func updateBorrowedFrom(in function: Function, _ context: some MutatingContext)
 }
 
 /// Update borrowed-from instructions for a set of phi arguments.
-func updateBorrowedFrom(for phis: some Sequence<Phi>, _ context: some MutatingContext) {
+public func updateBorrowedFrom(for phis: some Sequence<Phi>, _ context: some MutatingContext) {
   for phi in phis {
     if !phi.value.parentFunction.hasOwnership {
       return
@@ -67,7 +66,7 @@ func updateBorrowedFrom(for phis: some Sequence<Phi>, _ context: some MutatingCo
 }
 
 /// Updates the reborrow flags for all guaranteed phis in `function`.
-func updateReborrowFlags(in function: Function, _ context: some MutatingContext) {
+public func updateReborrowFlags(in function: Function, _ context: some MutatingContext) {
   if !function.hasOwnership {
     return
   }
@@ -90,7 +89,7 @@ func updateReborrowFlags(in function: Function, _ context: some MutatingContext)
 /// by cutting off the control flow before an `end_borrow`, the re-borrow flags still have to remain
 /// without the possibility to re-calculate them from the (now missing) `end_borrow`.
 ///
-func updateReborrowFlags(for phis: some Sequence<Phi>, _ context: some MutatingContext) {
+public func updateReborrowFlags(for phis: some Sequence<Phi>, _ context: some MutatingContext) {
   if let phi = phis.first(where: { phi in true }), !phi.value.parentFunction.hasOwnership {
     return
   }
@@ -138,7 +137,7 @@ private func createEmptyBorrowedFrom(for phi: Phi, _ context: some MutatingConte
   }
   let builder = Builder(atBeginOf: phi.value.parentBlock, context)
   let bfi = builder.createBorrowedFrom(borrowedValue: phi.value, enclosingValues: [])
-  phi.value.uses.ignoreUsers(ofType: BorrowedFromInst.self).replaceAll(with: bfi, context)
+  phi.value.uses.ignoreUses(ofType: BorrowedFromInst.self).replaceAll(with: bfi, context)
 }
 
 /// Replaces a phi with the unique incoming value if all incoming values are the same:
@@ -160,7 +159,7 @@ private func createEmptyBorrowedFrom(for phi: Phi, _ context: some MutatingConte
 ///     use(%1)
 /// ```
 ///
-func replacePhiWithIncomingValue(phi: Phi, _ context: some MutatingContext) -> Bool {
+public func replacePhiWithIncomingValue(phi: Phi, _ context: some MutatingContext) -> Bool {
   if phi.predecessors.isEmpty {
     return false
   }
@@ -207,7 +206,7 @@ func replacePhiWithIncomingValue(phi: Phi, _ context: some MutatingContext) -> B
 ///
 /// It's not needed to run this utility if SSAUpdater is used to create a _new_ OSSA liverange.
 ///
-func replacePhisWithIncomingValues(phis: [Phi], _ context: some MutatingContext) {
+public func replacePhisWithIncomingValues(phis: [Phi], _ context: some MutatingContext) {
   var currentPhis = phis
   // Do this in a loop because replacing one phi might open up the opportunity for another phi
   // and the order of phis in the array can be arbitrary.
@@ -228,14 +227,14 @@ func replacePhisWithIncomingValues(phis: [Phi], _ context: some MutatingContext)
 func registerPhiUpdater() {
   BridgedUtilities.registerPhiUpdater(
     // updateAllGuaranteedPhis
-    { (bridgedCtxt: BridgedPassContext, bridgedFunction: BridgedFunction) in
-      let context = FunctionPassContext(_bridged: bridgedCtxt)
+    { (bridgedCtxt: BridgedContext, bridgedFunction: BridgedFunction) in
+      let context = PhiUpdaterContext(_bridged: bridgedCtxt)
       let function = bridgedFunction.function;
       updateGuaranteedPhis(in: function, context)
     },
     // updateGuaranteedPhis
-    { (bridgedCtxt: BridgedPassContext, bridgedPhiArray: BridgedArrayRef) in
-      let context = FunctionPassContext(_bridged: bridgedCtxt)
+    { (bridgedCtxt: BridgedContext, bridgedPhiArray: BridgedArrayRef) in
+      let context = PhiUpdaterContext(_bridged: bridgedCtxt)
       var guaranteedPhis = Stack<Phi>(context)
       defer { guaranteedPhis.deinitialize() }
       bridgedPhiArray.withElements(ofType: BridgedValue.self) {
@@ -249,8 +248,8 @@ func registerPhiUpdater() {
       updateGuaranteedPhis(phis: guaranteedPhis, context)
     },
     // replacePhisWithIncomingValues
-    { (bridgedCtxt: BridgedPassContext, bridgedPhiArray: BridgedArrayRef) in
-      let context = FunctionPassContext(_bridged: bridgedCtxt)
+    { (bridgedCtxt: BridgedContext, bridgedPhiArray: BridgedArrayRef) in
+      let context = PhiUpdaterContext(_bridged: bridgedCtxt)
       var phis = [Phi]()
       bridgedPhiArray.withElements(ofType: BridgedValue.self) {
         phis = $0.map { Phi($0.value)! }
@@ -258,13 +257,9 @@ func registerPhiUpdater() {
       replacePhisWithIncomingValues(phis: phis, context)
     }
   )
-}
-
-/// This pass is only used for testing.
-/// In the regular pipeline it's not needed because optimization passes must make sure that borrowed-from
-/// instructions are updated once the pass finishes.
-let updateBorrowedFromPass = FunctionPass(name: "update-borrowed-from") {
-  (function: Function, context: FunctionPassContext) in
 
-  updateBorrowedFrom(in: function, context)
+  struct PhiUpdaterContext: MutatingContext {
+    let _bridged: BridgedContext
+    public let notifyInstructionChanged: (Instruction) -> () = { inst in }
+  }
 }
diff --git a/SwiftCompilerSources/Sources/SIL/Utilities/SSAUpdater.swift b/SwiftCompilerSources/Sources/SIL/Utilities/SSAUpdater.swift
new file mode 100644
index 0000000000000..6feaf4544b3c6
--- /dev/null
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/SSAUpdater.swift
@@ -0,0 +1,60 @@
+//===--- SSAUpdater.swift -------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SILBridging
+
+/// Utility for updating SSA for a set of SIL instructions defined in multiple blocks.
+public struct SSAUpdater<Context: MutatingContext> {
+  let context: Context
+
+  public init(function: Function, type: Type, ownership: Ownership, _ context: Context) {
+    self.context = context
+    context._bridged.SSAUpdater_initialize(function.bridged, type.bridged, ownership._bridged)
+  }
+
+  public mutating func addAvailableValue(_ value: Value, in block: BasicBlock) {
+    context._bridged.SSAUpdater_addAvailableValue(block.bridged, value.bridged)
+  }
+
+  /// Construct SSA for a value that is live at the *end* of a basic block.
+  public mutating func getValue(atEndOf block: BasicBlock) -> Value {
+    context.notifyInstructionsChanged()
+    return context._bridged.SSAUpdater_getValueAtEndOfBlock(block.bridged).value
+  }
+
+  /// Construct SSA for a value that is live in the *middle* of a block.
+  /// This handles the case where the use is before a definition of the value in the same block.
+  ///
+  ///   bb1:
+  ///     %1 = def
+  ///     br bb2
+  ///   bb2:
+  ///       = use(?)
+  ///    %2 = def
+  ///    cond_br bb2, bb3
+  ///
+  /// In this case we need to insert a phi argument in bb2, merging %1 and %2.
+  public mutating func getValue(inMiddleOf block: BasicBlock) -> Value {
+    context.notifyInstructionsChanged()
+    return context._bridged.SSAUpdater_getValueInMiddleOfBlock(block.bridged).value
+  }
+
+  public var insertedPhis: [Phi] {
+    var phis = [Phi]()
+    let numPhis = context._bridged.SSAUpdater_getNumInsertedPhis()
+    phis.reserveCapacity(numPhis)
+    for idx in 0..<numPhis {
+      phis.append(Phi(context._bridged.SSAUpdater_getInsertedPhi(idx).value)!)
+    }
+    return phis
+  }
+}
diff --git a/SwiftCompilerSources/Sources/SIL/Utilities/SmallProjectionPath.swift b/SwiftCompilerSources/Sources/SIL/Utilities/SmallProjectionPath.swift
index 188fd38fa1b51..0020e561ecd5a 100644
--- a/SwiftCompilerSources/Sources/SIL/Utilities/SmallProjectionPath.swift
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/SmallProjectionPath.swift
@@ -83,15 +83,17 @@ public struct SmallProjectionPath : Hashable, CustomStringConvertible, NoReflect
     // This and all following kinds (we'll add in the future) cannot have a field index.
     case tailElements   =    0x07 // (0 << 3) | 0x7    A tail allocated element of a class: syntax `ct`
     case existential    =    0x0f // (1 << 3) | 0x7    A concrete value projected out of an existential: synatx 'x'
-    case anyClassField  =    0x17 // (2 << 3) | 0x7    Any class field, including tail elements: syntax `c*`
-    case anyIndexedElement = 0x1f // (3 << 3) | 0x7    An unknown offset into an array of elements.
+    case vectorBase     =    0x17 // (2 << 3) | 0x7    The base element of a vector: synatx 'b'
+    case anyClassField  =    0x1f // (3 << 3) | 0x7    Any class field, including tail elements: syntax `c*`
+    case anyIndexedElement = 0x27 // (4 << 3) | 0x7    An unknown offset into an array of elements.
                                   // There must not be two successive element indices in the path.
-    case anyValueFields =    0x27 // (4 << 3) | 0x7    Any number of any value fields (struct, tuple, enum): syntax `v**`
-    case anything       =    0x2f // (5 << 3) | 0x7    Any number of any fields: syntax `**`
+    case anyValueFields =    0x2f // (5 << 3) | 0x7    Any number of any value fields (struct, tuple, enum): syntax `v**`
+    case anything       =    0x37 // (6 << 3) | 0x7    Any number of any fields: syntax `**`
 
     public var isValueField: Bool {
       switch self {
-        case .anyValueFields, .structField, .tupleField, .enumCase, .indexedElement, .anyIndexedElement, .existential:
+        case .structField, .tupleField, .enumCase, .indexedElement, .existential, .vectorBase,
+             .anyValueFields, .anyIndexedElement:
           return true
         case .root, .anything, .anyClassField, .classField, .tailElements:
           return false
@@ -102,7 +104,8 @@ public struct SmallProjectionPath : Hashable, CustomStringConvertible, NoReflect
       switch self {
         case .anyClassField, .classField, .tailElements:
           return true
-        case .root, .anything, .anyValueFields, .structField, .tupleField, .enumCase, .indexedElement, .anyIndexedElement, .existential:
+        case .root, .anything, .anyValueFields, .structField, .tupleField, .enumCase, .indexedElement,
+             .anyIndexedElement, .existential, .vectorBase:
           return false
       }
     }
@@ -140,6 +143,7 @@ public struct SmallProjectionPath : Hashable, CustomStringConvertible, NoReflect
       case .classField:     s = "c\(idx)"
       case .tailElements:   s = "ct"
       case .existential:    s = "x"
+      case .vectorBase:     s = "b"
       case .indexedElement: s = "i\(idx)"
       case .anyIndexedElement: s = "i*"
       case .anything:       s = "**"
@@ -186,7 +190,7 @@ public struct SmallProjectionPath : Hashable, CustomStringConvertible, NoReflect
 
   /// Pops \p numBits from the path.
   private func pop(numBits: Int) -> SmallProjectionPath {
-    return Self(bytes: bytes &>> numBits)
+    return Self(bytes: bytes >> numBits)
   }
 
   /// Pops and returns the first path component included the resulting path
@@ -210,7 +214,7 @@ public struct SmallProjectionPath : Hashable, CustomStringConvertible, NoReflect
           // Ignore zero indices
           return self
         }
-        if k == .indexedElement {
+        if k == .indexedElement && index &+ i >= 0 {
           // "Merge" two constant successive indexed elements
           return pop(numBits: numBits).push(.indexedElement, index: index + i)
         }
@@ -398,7 +402,7 @@ public struct SmallProjectionPath : Hashable, CustomStringConvertible, NoReflect
         return subPath.matches(pattern: subPattern)
       case .anyIndexedElement:
         return popIndexedElements().matches(pattern: subPattern)
-      case .structField, .tupleField, .enumCase, .classField, .tailElements, .indexedElement, .existential:
+      case .structField, .tupleField, .enumCase, .classField, .tailElements, .indexedElement, .existential, .vectorBase:
         let (kind, index, subPath) = pop()
         if kind != patternKind || index != patternIdx { return false }
         return subPath.matches(pattern: subPattern)
@@ -478,8 +482,18 @@ public struct SmallProjectionPath : Hashable, CustomStringConvertible, NoReflect
     }
     if (lhsKind == rhsKind && lhsIdx == rhsIdx) ||
        (lhsKind == .anyClassField && rhsKind.isClassField) ||
-       (lhsKind.isClassField && rhsKind == .anyClassField) {
-      return pop(numBits: lhsBits).mayOverlap(with: rhs.pop(numBits: rhsBits))
+       (lhsKind.isClassField && rhsKind == .anyClassField)
+    {
+      let poppedPath = pop(numBits: lhsBits)
+      let rhsPoppedPath = rhs.pop(numBits: rhsBits)
+      // Check for the case of overlapping the first element of a vector with another element.
+      // Note that the index of `.indexedElement` cannot be 0.
+      if (poppedPath.isEmpty && rhsPoppedPath.pop().kind == .indexedElement) ||
+         (rhsPoppedPath.isEmpty && poppedPath.pop().kind == .indexedElement)
+      {
+        return false
+      }
+      return poppedPath.mayOverlap(with: rhsPoppedPath)
     }
     return false
   }
@@ -496,7 +510,7 @@ public struct SmallProjectionPath : Hashable, CustomStringConvertible, NoReflect
     switch lhsKind {
     case .root:
       return rhs
-    case .classField, .tailElements, .structField, .tupleField, .enumCase, .existential, .indexedElement:
+    case .classField, .tailElements, .structField, .tupleField, .enumCase, .existential, .indexedElement, .vectorBase:
       let (rhsKind, rhsIdx, rhsBits) = rhs.top
       if lhsKind == rhsKind && lhsIdx == rhsIdx {
         return pop(numBits: lhsBits).subtract(from: rhs.pop(numBits: rhsBits))
@@ -520,6 +534,18 @@ public struct SmallProjectionPath : Hashable, CustomStringConvertible, NoReflect
       return false
     }
   }
+  
+  public var isConstant: Bool {
+    let (kind, _, subPath) = pop()
+    switch kind {
+    case .root:
+      return true
+    case .structField, .tupleField, .enumCase, .classField, .existential, .indexedElement:
+      return subPath.isConstant
+    default:
+      return false
+    }
+  }
 }
 
 //===----------------------------------------------------------------------===//
@@ -601,6 +627,8 @@ extension StringParser {
         entries.append((.tailElements, 0))
       } else if consume("x") {
         entries.append((.existential, 0))
+      } else if consume("b") {
+        entries.append((.vectorBase, 0))
       } else if consume("c") {
         guard let idx = consumeInt(withWhiteSpace: false) else {
           try throwError("expected class field index")
@@ -652,278 +680,307 @@ extension StringParser {
 //                               Unit Tests
 //===----------------------------------------------------------------------===//
 
-extension SmallProjectionPath {
-  public static func runUnitTests() {
-  
-    basicPushPop()
-    parsing()
-    merging()
-    subtracting()
-    matching()
-    overlapping()
-    predicates()
-    path2path()
-  
-    func basicPushPop() {
-      let p1 = SmallProjectionPath(.structField, index: 3)
-                        .push(.classField, index: 12345678)
-      let (k2, i2, p2) = p1.pop()
-      assert(k2 == .classField && i2 == 12345678)
-      let (k3, i3, p3) = p2.pop()
-      assert(k3 == .structField && i3 == 3)
-      assert(p3.isEmpty)
-      let (k4, i4, _) = p2.push(.enumCase, index: 876).pop()
-      assert(k4 == .enumCase && i4 == 876)
-      let p5 = SmallProjectionPath(.anything)
-      assert(p5.pop().path.isEmpty)
-      let p6 = SmallProjectionPath(.indexedElement, index: 1).push(.indexedElement, index: 2)
-      let (k6, i6, p7) = p6.pop()
-      assert(k6 == .indexedElement && i6 == 3 && p7.isEmpty)
-      let p8 = SmallProjectionPath(.indexedElement, index: 0)
-      assert(p8.isEmpty)
-      let p9 = SmallProjectionPath(.indexedElement, index: 1).push(.anyIndexedElement)
-      let (k9, i9, p10) = p9.pop()
-      assert(k9 == .anyIndexedElement && i9 == 0 && p10.isEmpty)
-      let p11 = SmallProjectionPath(.anyIndexedElement).push(.indexedElement, index: 1)
-      let (k11, i11, p12) = p11.pop()
-      assert(k11 == .anyIndexedElement && i11 == 0 && p12.isEmpty)
-    }
-    
-    func parsing() {
-      testParse("v**.c*", expect: SmallProjectionPath(.anyClassField)
-                                         .push(.anyValueFields))
-      testParse("s3.c*.v**.s1", expect: SmallProjectionPath(.structField, index: 1)
-                                         .push(.anyValueFields)
-                                         .push(.anyClassField)
-                                         .push(.structField, index: 3))
-      testParse("2.c*.e6.ct.**", expect: SmallProjectionPath(.anything)
-                                         .push(.tailElements)
-                                         .push(.enumCase, index: 6)
-                                         .push(.anyClassField)
-                                         .push(.tupleField, index: 2))
-      testParse("i3.x.i*", expect: SmallProjectionPath(.anyIndexedElement)
-                                         .push(.existential)
-                                         .push(.indexedElement, index: 3))
-
-      do {
-        var parser = StringParser("c*.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.**")
-        _ = try parser.parseProjectionPathFromSIL()
-        fatalError("too long path not detected")
-      } catch {
-      }
-      do {
-        var parser = StringParser("**.s0")
-        _ = try parser.parseProjectionPathFromSIL()
-        fatalError("wrong '**' not detected")
-      } catch {
-      }
+let smallProjectionPathTest = Test("small_projection_path") {
+  function, arguments, context in
+
+  basicPushPop()
+  parsing()
+  merging()
+  subtracting()
+  matching()
+  overlapping()
+  predicates()
+  path2path()
+  indexedElements()
+
+  func basicPushPop() {
+    let p1 = SmallProjectionPath(.structField, index: 3)
+                      .push(.classField, index: 12345678)
+    let (k2, i2, p2) = p1.pop()
+    assert(k2 == .classField && i2 == 12345678)
+    let (k3, i3, p3) = p2.pop()
+    assert(k3 == .structField && i3 == 3)
+    assert(p3.isEmpty)
+    let (k4, i4, _) = p2.push(.enumCase, index: 876).pop()
+    assert(k4 == .enumCase && i4 == 876)
+    let p5 = SmallProjectionPath(.anything)
+    assert(p5.pop().path.isEmpty)
+    let p6 = SmallProjectionPath(.indexedElement, index: 1).push(.indexedElement, index: 2)
+    let (k6, i6, p7) = p6.pop()
+    assert(k6 == .indexedElement && i6 == 3 && p7.isEmpty)
+    let p8 = SmallProjectionPath(.indexedElement, index: 0)
+    assert(p8.isEmpty)
+    let p9 = SmallProjectionPath(.indexedElement, index: 1).push(.anyIndexedElement)
+    let (k9, i9, p10) = p9.pop()
+    assert(k9 == .anyIndexedElement && i9 == 0 && p10.isEmpty)
+    let p11 = SmallProjectionPath(.anyIndexedElement).push(.indexedElement, index: 1)
+    let (k11, i11, p12) = p11.pop()
+    assert(k11 == .anyIndexedElement && i11 == 0 && p12.isEmpty)
+  }
+
+  func parsing() {
+    testParse("v**.c*", expect: SmallProjectionPath(.anyClassField)
+                                       .push(.anyValueFields))
+    testParse("s3.c*.v**.s1", expect: SmallProjectionPath(.structField, index: 1)
+                                       .push(.anyValueFields)
+                                       .push(.anyClassField)
+                                       .push(.structField, index: 3))
+    testParse("2.c*.e6.ct.**", expect: SmallProjectionPath(.anything)
+                                       .push(.tailElements)
+                                       .push(.enumCase, index: 6)
+                                       .push(.anyClassField)
+                                       .push(.tupleField, index: 2))
+    testParse("i3.x.b.i*", expect: SmallProjectionPath(.anyIndexedElement)
+                                       .push(.vectorBase)
+                                       .push(.existential)
+                                       .push(.indexedElement, index: 3))
+
+    do {
+      var parser = StringParser("c*.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.s123.s3.**")
+      _ = try parser.parseProjectionPathFromSIL()
+      fatalError("too long path not detected")
+    } catch {
+    }
+    do {
+      var parser = StringParser("**.s0")
+      _ = try parser.parseProjectionPathFromSIL()
+      fatalError("wrong '**' not detected")
+    } catch {
     }
+  }
+
+  func testParse(_ pathStr: String, expect: SmallProjectionPath) {
+    var parser = StringParser(pathStr)
+    let path = try! parser.parseProjectionPathFromSIL()
+    assert(path == expect)
+    let str = path.description
+    assert(str == pathStr)
+  }
+
+  func merging() {
+    testMerge("c1.c0",    "c0",     expect: "c*.**")
+    testMerge("c2.c1",    "c2",     expect: "c2.**")
+    testMerge("s3.c0",    "v**.c0", expect: "v**.c0")
+    testMerge("c0",       "s2.c1",  expect: "v**.c*")
+    testMerge("s1.s1.c2", "s1.c2",  expect: "s1.v**.c2")
+    testMerge("s1.s0",    "s2.s0",  expect: "v**")
+    testMerge("ct",       "c2",     expect: "c*")
+    testMerge("i1",       "i2",     expect: "i*")
+    testMerge("i*",       "i2",     expect: "i*")
+    testMerge("s0.i*.e3", "s0.e3",  expect: "s0.i*.e3")
+    testMerge("i*",       "v**",    expect: "v**")
+    testMerge("s0.b.i1",  "s0.b.i0", expect: "s0.b.i*")
+    testMerge("s0.b",     "s0.1",   expect: "s0.v**")
+
+    testMerge("ct.s0.e0.v**.c0", "ct.s0.e0.v**.c0", expect: "ct.s0.e0.v**.c0")
+    testMerge("ct.s0.s0.c0",     "ct.s0.e0.s0.c0",  expect: "ct.s0.v**.c0")
+  }
+
+  func testMerge(_ lhsStr: String, _ rhsStr: String,
+                 expect expectStr: String) {
+    var lhsParser = StringParser(lhsStr)
+    let lhs = try! lhsParser.parseProjectionPathFromSIL()
+    var rhsParser = StringParser(rhsStr)
+    let rhs = try! rhsParser.parseProjectionPathFromSIL()
+    var expectParser = StringParser(expectStr)
+    let expect = try! expectParser.parseProjectionPathFromSIL()
+
+    let result = lhs.merge(with: rhs)
+    assert(result == expect)
+    let result2 = rhs.merge(with: lhs)
+    assert(result2 == expect)
+  }
+
+  func subtracting() {
+    testSubtract("s0",           "s0.s1",        expect: "s1")
+    testSubtract("s0",           "s1",           expect: nil)
+    testSubtract("s0.s1",        "s0.s1",        expect: "")
+    testSubtract("i*.s1",        "i*.s1",        expect: nil)
+    testSubtract("ct.s1.0.i3.x", "ct.s1.0.i3.x", expect: "")
+    testSubtract("c0.s1.0.i3",   "c0.s1.0.i3.x", expect: "x")
+    testSubtract("s1.0.i3.x",    "s1.0.i3",      expect: nil)
+    testSubtract("v**.s1",       "v**.s1",       expect: nil)
+    testSubtract("i*",           "i*",           expect: nil)
+  }
+
+  func testSubtract(_ lhsStr: String, _ rhsStr: String, expect expectStr: String?) {
+    var lhsParser = StringParser(lhsStr)
+    let lhs = try! lhsParser.parseProjectionPathFromSIL()
+    var rhsParser = StringParser(rhsStr)
+    let rhs = try! rhsParser.parseProjectionPathFromSIL()
+
+    let result = lhs.subtract(from: rhs)
 
-    func testParse(_ pathStr: String, expect: SmallProjectionPath) {
-      var parser = StringParser(pathStr)
-      let path = try! parser.parseProjectionPathFromSIL()
-      assert(path == expect)
-      let str = path.description
-      assert(str == pathStr)
-    }
-   
-    func merging() {
-      testMerge("c1.c0",    "c0",     expect: "c*.**")
-      testMerge("c2.c1",    "c2",     expect: "c2.**")
-      testMerge("s3.c0",    "v**.c0", expect: "v**.c0")
-      testMerge("c0",       "s2.c1",  expect: "v**.c*")
-      testMerge("s1.s1.c2", "s1.c2",  expect: "s1.v**.c2")
-      testMerge("s1.s0",    "s2.s0",  expect: "v**")
-      testMerge("ct",       "c2",     expect: "c*")
-      testMerge("i1",       "i2",     expect: "i*")
-      testMerge("i*",       "i2",     expect: "i*")
-      testMerge("s0.i*.e3", "s0.e3",  expect: "s0.i*.e3")
-      testMerge("i*",       "v**",    expect: "v**")
-
-      testMerge("ct.s0.e0.v**.c0", "ct.s0.e0.v**.c0", expect: "ct.s0.e0.v**.c0")
-      testMerge("ct.s0.s0.c0",     "ct.s0.e0.s0.c0",  expect: "ct.s0.v**.c0")
-    }
-
-    func testMerge(_ lhsStr: String, _ rhsStr: String,
-                   expect expectStr: String) {
-      var lhsParser = StringParser(lhsStr)
-      let lhs = try! lhsParser.parseProjectionPathFromSIL()
-      var rhsParser = StringParser(rhsStr)
-      let rhs = try! rhsParser.parseProjectionPathFromSIL()
+    if let expectStr = expectStr {
       var expectParser = StringParser(expectStr)
       let expect = try! expectParser.parseProjectionPathFromSIL()
-
-      let result = lhs.merge(with: rhs)
-      assert(result == expect)
-      let result2 = rhs.merge(with: lhs)
-      assert(result2 == expect)
-    }
-   
-    func subtracting() {
-      testSubtract("s0",           "s0.s1",        expect: "s1")
-      testSubtract("s0",           "s1",           expect: nil)
-      testSubtract("s0.s1",        "s0.s1",        expect: "")
-      testSubtract("i*.s1",        "i*.s1",        expect: nil)
-      testSubtract("ct.s1.0.i3.x", "ct.s1.0.i3.x", expect: "")
-      testSubtract("c0.s1.0.i3",   "c0.s1.0.i3.x", expect: "x")
-      testSubtract("s1.0.i3.x",    "s1.0.i3",      expect: nil)
-      testSubtract("v**.s1",       "v**.s1",       expect: nil)
-      testSubtract("i*",           "i*",           expect: nil)
-    }
-
-    func testSubtract(_ lhsStr: String, _ rhsStr: String, expect expectStr: String?) {
-      var lhsParser = StringParser(lhsStr)
-      let lhs = try! lhsParser.parseProjectionPathFromSIL()
-      var rhsParser = StringParser(rhsStr)
-      let rhs = try! rhsParser.parseProjectionPathFromSIL()
-
-      let result = lhs.subtract(from: rhs)
-
-      if let expectStr = expectStr {
-        var expectParser = StringParser(expectStr)
-        let expect = try! expectParser.parseProjectionPathFromSIL()
-        assert(result! == expect)
-      } else {
-        assert(result == nil)
-      }
+      assert(result! == expect)
+    } else {
+      assert(result == nil)
     }
+  }
 
-    func matching() {
-      testMatch("ct", "c*",  expect: true)
-      testMatch("c1", "c*",  expect: true)
-      testMatch("s2", "v**", expect: true)
-      testMatch("1",  "v**", expect: true)
-      testMatch("e1", "v**", expect: true)
-      testMatch("c*", "c1",  expect: false)
-      testMatch("c*", "ct",  expect: false)
-      testMatch("v**", "s0", expect: false)
-      testMatch("i1", "i1",  expect: true)
-      testMatch("i1", "i*",  expect: true)
-      testMatch("i*", "i1",  expect: false)
-
-      testMatch("s0.s1", "s0.s1",     expect: true)
-      testMatch("s0.s2", "s0.s1",     expect: false)
-      testMatch("s0", "s0.v**",       expect: true)
-      testMatch("s0.s1", "s0.v**",    expect: true)
-      testMatch("s0.1.e2", "s0.v**",  expect: true)
-      testMatch("s0.v**.x.e2", "v**", expect: true)
-      testMatch("s0.v**", "s0.s1",    expect: false)
-      testMatch("s0.s1.c*", "s0.v**", expect: false)
-      testMatch("s0.v**", "s0.**",    expect: true)
-      testMatch("s1.v**", "s0.**",    expect: false)
-      testMatch("s0.**", "s0.v**",    expect: false)
-      testMatch("s0.s1", "s0.i*.s1",  expect: true)
-    }
-
-    func testMatch(_ lhsStr: String, _ rhsStr: String, expect: Bool) {
-      var lhsParser = StringParser(lhsStr)
-      let lhs = try! lhsParser.parseProjectionPathFromSIL()
-      var rhsParser = StringParser(rhsStr)
-      let rhs = try! rhsParser.parseProjectionPathFromSIL()
-      let result = lhs.matches(pattern: rhs)
-      assert(result == expect)
-    }
-
-    func overlapping() {
-      testOverlap("s0.s1.s2", "s0.s1.s2",     expect: true)
-      testOverlap("s0.s1.s2", "s0.s2.s2",     expect: false)
-      testOverlap("s0.s1.s2", "s0.e1.s2",     expect: false)
-      testOverlap("s0.s1.s2", "s0.s1",        expect: true)
-      testOverlap("s0.s1.s2", "s1.s2",        expect: false)
-
-      testOverlap("s0.c*.s2", "s0.ct.s2",     expect: true)
-      testOverlap("s0.c*.s2", "s0.c1.s2",     expect: true)
-      testOverlap("s0.c*.s2", "s0.c1.c2.s2",  expect: false)
-      testOverlap("s0.c*.s2", "s0.s2",        expect: false)
-
-      testOverlap("s0.v**.s2", "s0.s3.x",     expect: true)
-      testOverlap("s0.v**.s2.c2", "s0.s3.c1", expect: false)
-      testOverlap("s0.v**.s2", "s1.s3",       expect: false)
-      testOverlap("s0.v**.s2", "s0.v**.s3",   expect: true)
-
-      testOverlap("s0.**", "s0.s3.c1",        expect: true)
-      testOverlap("**", "s0.s3.c1",           expect: true)
-
-      testOverlap("i1", "i*",                 expect: true)
-      testOverlap("i1", "v**",                expect: true)
-      testOverlap("s0.i*.s1", "s0.s1",        expect: true)
-    }
-
-    func testOverlap(_ lhsStr: String, _ rhsStr: String, expect: Bool) {
-      var lhsParser = StringParser(lhsStr)
-      let lhs = try! lhsParser.parseProjectionPathFromSIL()
-      var rhsParser = StringParser(rhsStr)
-      let rhs = try! rhsParser.parseProjectionPathFromSIL()
-      let result = lhs.mayOverlap(with: rhs)
-      assert(result == expect)
-      let reversedResult = rhs.mayOverlap(with: lhs)
-      assert(reversedResult == expect)
-    }
-
-    func predicates() {
-      testPredicate("v**",           \.hasClassProjection, expect: false)
-      testPredicate("v**.c0.s1.v**", \.hasClassProjection, expect: true)
-      testPredicate("c0.**",         \.hasClassProjection, expect: true)
-      testPredicate("c0.c1",         \.hasClassProjection, expect: true)
-      testPredicate("ct",            \.hasClassProjection, expect: true)
-      testPredicate("s0",            \.hasClassProjection, expect: false)
-
-      testPredicate("v**", \.mayHaveClassProjection, expect: false)
-      testPredicate("c0",  \.mayHaveClassProjection, expect: true)
-      testPredicate("1",   \.mayHaveClassProjection, expect: false)
-      testPredicate("**",  \.mayHaveClassProjection, expect: true)
-
-      testPredicate("v**", \.mayHaveTwoClassProjections, expect: false)
-      testPredicate("c0",  \.mayHaveTwoClassProjections, expect: false)
-      testPredicate("**",  \.mayHaveTwoClassProjections, expect: true)
-      testPredicate("v**.c*.s2.1.c0",   \.mayHaveTwoClassProjections, expect: true)
-      testPredicate("c*.s2.1.c0.v**",   \.mayHaveTwoClassProjections, expect: true)
-      testPredicate("v**.c*.**",        \.mayHaveTwoClassProjections, expect: true)
-    }
-
-    func testPredicate(_ pathStr: String, _ property: (SmallProjectionPath) -> Bool, expect: Bool) {
-      var parser = StringParser(pathStr)
-      let path = try! parser.parseProjectionPathFromSIL()
-      let result = property(path)
-      assert(result == expect)
-    }
-    
-    func path2path() {
-      testPath2Path("s0.e2.3.c4.s1", { $0.popAllValueFields() }, expect: "c4.s1")
-      testPath2Path("v**.c4.s1",     { $0.popAllValueFields() }, expect: "c4.s1")
-      testPath2Path("**",            { $0.popAllValueFields() }, expect: "**")
-
-      testPath2Path("s0.e2.3.c4.s1.e2.v**.**", { $0.popLastClassAndValuesFromTail() }, expect: "s0.e2.3.c4.s1.e2.v**.**")
-      testPath2Path("s0.c2.3.c4.s1",           { $0.popLastClassAndValuesFromTail() }, expect: "s0.c2.3")
-      testPath2Path("v**.c*.s1",               { $0.popLastClassAndValuesFromTail() }, expect: "v**")
-      testPath2Path("s1.ct.v**",               { $0.popLastClassAndValuesFromTail() }, expect: "s1")
-      testPath2Path("c0.c1.c2",                { $0.popLastClassAndValuesFromTail() }, expect: "c0.c1")
-      testPath2Path("**",                      { $0.popLastClassAndValuesFromTail() }, expect: "**")
-
-      testPath2Path("v**.c3", { $0.popIfMatches(.anyValueFields) }, expect: "v**.c3")
-      testPath2Path("**",     { $0.popIfMatches(.anyValueFields) }, expect: "**")
-      testPath2Path("s0.c3",  { $0.popIfMatches(.anyValueFields) }, expect: nil)
-      
-      testPath2Path("c0.s3",  { $0.popIfMatches(.anyClassField) }, expect: nil)
-      testPath2Path("**",     { $0.popIfMatches(.anyClassField) }, expect: "**")
-      testPath2Path("c*.e3",  { $0.popIfMatches(.anyClassField) }, expect: "e3")
-
-      testPath2Path("i*.e3.s0", { $0.popIfMatches(.enumCase, index: 3) }, expect: "s0")
-      testPath2Path("i1.e3.s0", { $0.popIfMatches(.enumCase, index: 3) }, expect: nil)
-      testPath2Path("i*.e3.s0", { $0.popIfMatches(.indexedElement, index: 0) }, expect: "i*.e3.s0")
-    }
-
-    func testPath2Path(_ pathStr: String, _ transform: (SmallProjectionPath) -> SmallProjectionPath?, expect: String?) {
-      var parser = StringParser(pathStr)
-      let path = try! parser.parseProjectionPathFromSIL()
-      let result = transform(path)
-      if let expect = expect {
-        var expectParser = StringParser(expect)
-        let expectPath = try! expectParser.parseProjectionPathFromSIL()
-        assert(result == expectPath)
-      } else {
-        assert(result == nil)
-      }
+  func matching() {
+    testMatch("ct", "c*",  expect: true)
+    testMatch("c1", "c*",  expect: true)
+    testMatch("s2", "v**", expect: true)
+    testMatch("1",  "v**", expect: true)
+    testMatch("e1", "v**", expect: true)
+    testMatch("c*", "c1",  expect: false)
+    testMatch("c*", "ct",  expect: false)
+    testMatch("v**", "s0", expect: false)
+    testMatch("i1", "i1",  expect: true)
+    testMatch("i1", "i*",  expect: true)
+    testMatch("i*", "i1",  expect: false)
+
+    testMatch("s0.s1", "s0.s1",     expect: true)
+    testMatch("s0.s2", "s0.s1",     expect: false)
+    testMatch("s0", "s0.v**",       expect: true)
+    testMatch("s0.s1", "s0.v**",    expect: true)
+    testMatch("s0.1.e2", "s0.v**",  expect: true)
+    testMatch("s0.v**.x.e2", "v**", expect: true)
+    testMatch("s0.v**", "s0.s1",    expect: false)
+    testMatch("s0.s1.c*", "s0.v**", expect: false)
+    testMatch("s0.v**", "s0.**",    expect: true)
+    testMatch("s1.v**", "s0.**",    expect: false)
+    testMatch("s0.**", "s0.v**",    expect: false)
+    testMatch("s0.s1", "s0.i*.s1",  expect: true)
+    testMatch("s0.b.s1", "s0.b.i*.s1",  expect: true)
+  }
+
+  func testMatch(_ lhsStr: String, _ rhsStr: String, expect: Bool) {
+    var lhsParser = StringParser(lhsStr)
+    let lhs = try! lhsParser.parseProjectionPathFromSIL()
+    var rhsParser = StringParser(rhsStr)
+    let rhs = try! rhsParser.parseProjectionPathFromSIL()
+    let result = lhs.matches(pattern: rhs)
+    assert(result == expect)
+  }
+
+  func overlapping() {
+    testOverlap("s0.s1.s2", "s0.s1.s2",     expect: true)
+    testOverlap("s0.s1.s2", "s0.s2.s2",     expect: false)
+    testOverlap("s0.s1.s2", "s0.e1.s2",     expect: false)
+    testOverlap("s0.s1.s2", "s0.s1",        expect: true)
+    testOverlap("s0.s1.s2", "s1.s2",        expect: false)
+
+    testOverlap("s0.c*.s2", "s0.ct.s2",     expect: true)
+    testOverlap("s0.c*.s2", "s0.c1.s2",     expect: true)
+    testOverlap("s0.c*.s2", "s0.c1.c2.s2",  expect: false)
+    testOverlap("s0.c*.s2", "s0.s2",        expect: false)
+
+    testOverlap("s0.v**.s2", "s0.s3.x",     expect: true)
+    testOverlap("s0.v**.s2.c2", "s0.s3.c1", expect: false)
+    testOverlap("s0.v**.s2", "s1.s3",       expect: false)
+    testOverlap("s0.v**.s2", "s0.v**.s3",   expect: true)
+
+    testOverlap("s0.**", "s0.s3.c1",        expect: true)
+    testOverlap("**", "s0.s3.c1",           expect: true)
+
+    testOverlap("i1", "i*",                 expect: true)
+    testOverlap("i1", "v**",                expect: true)
+    testOverlap("s0.i*.s1", "s0.s1",        expect: true)
+    testOverlap("s0.b.s1", "s0.b.i*.s1",    expect: true)
+    testOverlap("s0.b.i0.s1", "s0.b.i1.s1", expect: false)
+    testOverlap("s0.b.i2.s1", "s0.b.i1.s1", expect: false)
+    testOverlap("s0.b.s1", "s0.b.i0.s1",    expect: true)
+    testOverlap("s0.b", "s0.b.i1",          expect: false)
+    testOverlap("s0.b.i1", "s0.b",          expect: false)
+    testOverlap("s0.b.i1", "s0",            expect: true)
+  }
+
+  func testOverlap(_ lhsStr: String, _ rhsStr: String, expect: Bool) {
+    var lhsParser = StringParser(lhsStr)
+    let lhs = try! lhsParser.parseProjectionPathFromSIL()
+    var rhsParser = StringParser(rhsStr)
+    let rhs = try! rhsParser.parseProjectionPathFromSIL()
+    let result = lhs.mayOverlap(with: rhs)
+    assert(result == expect)
+    let reversedResult = rhs.mayOverlap(with: lhs)
+    assert(reversedResult == expect)
+  }
+
+  func predicates() {
+    testPredicate("v**",           \.hasClassProjection, expect: false)
+    testPredicate("v**.c0.s1.v**", \.hasClassProjection, expect: true)
+    testPredicate("c0.**",         \.hasClassProjection, expect: true)
+    testPredicate("c0.c1",         \.hasClassProjection, expect: true)
+    testPredicate("ct",            \.hasClassProjection, expect: true)
+    testPredicate("s0",            \.hasClassProjection, expect: false)
+
+    testPredicate("v**", \.mayHaveClassProjection, expect: false)
+    testPredicate("c0",  \.mayHaveClassProjection, expect: true)
+    testPredicate("1",   \.mayHaveClassProjection, expect: false)
+    testPredicate("**",  \.mayHaveClassProjection, expect: true)
+
+    testPredicate("v**", \.mayHaveTwoClassProjections, expect: false)
+    testPredicate("c0",  \.mayHaveTwoClassProjections, expect: false)
+    testPredicate("**",  \.mayHaveTwoClassProjections, expect: true)
+    testPredicate("v**.c*.s2.1.c0",   \.mayHaveTwoClassProjections, expect: true)
+    testPredicate("c*.s2.1.c0.v**",   \.mayHaveTwoClassProjections, expect: true)
+    testPredicate("v**.c*.**",        \.mayHaveTwoClassProjections, expect: true)
+  }
+
+  func testPredicate(_ pathStr: String, _ property: (SmallProjectionPath) -> Bool, expect: Bool) {
+    var parser = StringParser(pathStr)
+    let path = try! parser.parseProjectionPathFromSIL()
+    let result = property(path)
+    assert(result == expect)
+  }
+
+  func path2path() {
+    testPath2Path("s0.b.e2.3.c4.s1", { $0.popAllValueFields() }, expect: "c4.s1")
+    testPath2Path("v**.c4.s1",     { $0.popAllValueFields() }, expect: "c4.s1")
+    testPath2Path("**",            { $0.popAllValueFields() }, expect: "**")
+
+    testPath2Path("s0.e2.3.c4.s1.e2.v**.**", { $0.popLastClassAndValuesFromTail() }, expect: "s0.e2.3.c4.s1.e2.v**.**")
+    testPath2Path("s0.c2.3.c4.s1",           { $0.popLastClassAndValuesFromTail() }, expect: "s0.c2.3")
+    testPath2Path("v**.c*.s1",               { $0.popLastClassAndValuesFromTail() }, expect: "v**")
+    testPath2Path("s1.ct.v**",               { $0.popLastClassAndValuesFromTail() }, expect: "s1")
+    testPath2Path("c0.c1.c2",                { $0.popLastClassAndValuesFromTail() }, expect: "c0.c1")
+    testPath2Path("**",                      { $0.popLastClassAndValuesFromTail() }, expect: "**")
+
+    testPath2Path("v**.c3", { $0.popIfMatches(.anyValueFields) }, expect: "v**.c3")
+    testPath2Path("**",     { $0.popIfMatches(.anyValueFields) }, expect: "**")
+    testPath2Path("s0.c3",  { $0.popIfMatches(.anyValueFields) }, expect: nil)
+
+    testPath2Path("c0.s3",  { $0.popIfMatches(.anyClassField) }, expect: nil)
+    testPath2Path("**",     { $0.popIfMatches(.anyClassField) }, expect: "**")
+    testPath2Path("c*.e3",  { $0.popIfMatches(.anyClassField) }, expect: "e3")
+
+    testPath2Path("i*.e3.s0", { $0.popIfMatches(.enumCase, index: 3) }, expect: "s0")
+    testPath2Path("i1.e3.s0", { $0.popIfMatches(.enumCase, index: 3) }, expect: nil)
+    testPath2Path("i*.e3.s0", { $0.popIfMatches(.indexedElement, index: 0) }, expect: "i*.e3.s0")
+  }
+
+  func testPath2Path(_ pathStr: String, _ transform: (SmallProjectionPath) -> SmallProjectionPath?, expect: String?) {
+    var parser = StringParser(pathStr)
+    let path = try! parser.parseProjectionPathFromSIL()
+    let result = transform(path)
+    if let expect = expect {
+      var expectParser = StringParser(expect)
+      let expectPath = try! expectParser.parseProjectionPathFromSIL()
+      assert(result == expectPath)
+    } else {
+      assert(result == nil)
     }
   }
+
+  func indexedElements() {
+    let p1 = SmallProjectionPath(.indexedElement, index: 1)
+    let (k1, i1, s1) = p1.pop()
+    assert(k1 == .indexedElement && i1 == 1 && s1.isEmpty)
+
+    let p2 = SmallProjectionPath(.indexedElement, index: -1)
+    let (k2, _, s2) = p2.pop()
+    assert(k2 == .anything && s2.isEmpty)
+
+    let p3 = SmallProjectionPath(.indexedElement, index: 0xfffffffffffff)
+    let (k3, i3, s3) = p3.pop()
+    assert(k3 == .indexedElement && i3 == 0xfffffffffffff && s3.isEmpty)
+
+    let p4 = p3.push(.indexedElement, index: Int.max)
+    let (k4, _, s4) = p4.pop()
+    assert(k4 == .anyIndexedElement && s4.isEmpty)
+  }
 }
diff --git a/SwiftCompilerSources/Sources/SIL/Utilities/Test.swift b/SwiftCompilerSources/Sources/SIL/Utilities/Test.swift
new file mode 100644
index 0000000000000..8206f5b7b40f8
--- /dev/null
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/Test.swift
@@ -0,0 +1,251 @@
+//===----------- Test.swift - In-IR tests from Swift source ---------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// TO ADD A NEW TEST, just add a new Test instance.
+// - In the source file containing the functionality you want to test:
+//       let myNewTest = Test("my_new_test") { function, arguments, context in
+//       }
+// - In SwiftCompilerSources/Sources/SIL/Test.swift's registerTests
+//   function, add a new argument to the variadic function:
+//       registerTests(..., myNewTest)
+//
+//===----------------------------------------------------------------------===//
+//
+// Provides a mechanism for writing tests against compiler code in the context
+// of a function. The goal is to get the same effect as calling a function and
+// checking its output.
+//
+// This is done via the specify_test instruction. Using one or more instances
+// of it in your test case's SIL function, you can specify which test (instance
+// of Test) should be run and what arguments should be provided to it.
+// For full details of the specify_test instruction's grammar,
+// see doc/SIL/Instructions.md.
+//
+// The test grabs the arguments it expects out of the TestArguments instance
+// it is provided.  It calls some function or functions.  It then prints out
+// interesting results.  These results can then be FileCheck'd.
+//
+// CASE STUDY:
+// Here's an example of how it works:
+// 0) A source file, NeatUtils.swift contains
+//
+//    fileprivate func myNeatoUtility(int: Int, value: Value, function: Function) { ... }
+//
+//    and
+//
+//    let myNeatoUtilityTest = Test("my_neato_utility") { function, arguments, test in
+//         // The code here is described in detail below.
+//         // See 4).
+//         let count = arguments.takeInt()
+//         let target = arguments.takeValue()
+//         let callee = arguments.takeFunction()
+//         // See 5)
+//         myNeatoUtility(int: count, value: target, function: callee)
+//         // See 6)
+//         print(function)
+//      }
+// 1) A test test/SILOptimizer/interesting_functionality_unit.sil runs the
+//    TestRunner pass:
+//     // RUN: %target-sil-opt -test-runner %s -o /dev/null 2>&1 | %FileCheck %s
+//     // REQUIRES: swift_in_compiler
+// 2) A function in interesting_functionality_unit.sil contains the
+//    specify_test instruction.
+//      sil @f : $() -> () {
+//      ...
+//      specify_test "my_neato_utility 43 %2 @function[other_fun]"
+//      ...
+//      }
+// 3) TestRunner finds the Test instance myNeatoUtilityTest registered
+//    under the name "my_neato_utility", and calls run() on it, passing the
+//    passing first the function, last the Test instance, AND in the
+//    middle, most importantly a TestArguments instance that contains
+//
+//      (43 : Int, someValue : Value, other_fun : Function)
+//
+// 4) myNeatoUtilityTest calls takeUInt(), takeValue(), and takeFunction() on
+//    the test::Arguments instance.
+//      let count = arguments.takeInt()
+//      let target = arguments.takeValue()
+//      let callee = arguments.takeFunction()
+// 5) myNeatoUtilityTest calls myNeatoUtility, passing these values along.
+//      myNeatoUtility(int: count, value: target, function: callee)
+// 6) myNeatoUtilityTest then dumps out the current function, which was modified
+//    in the process.
+//      print(function)
+// 7) The test file test/SILOptimizer/interesting_functionality_unit.sil matches
+// the
+//    expected contents of the modified function:
+//    // CHECK-LABEL: sil @f
+//    // CHECK-NOT:     function_ref @other_fun
+//
+//===----------------------------------------------------------------------===//
+
+import Basic
+import SILBridging
+
+/// The primary interface to in-IR tests.
+public struct Test {
+  let name: String
+  let invocation: TestInvocation
+
+  public init(_ name: String, invocation: @escaping TestInvocation) {
+    self.name = name
+    self.invocation = invocation
+  }
+}
+
+/// The type of the closure passed to a Test.
+public typealias TestInvocation = @convention(thin) (Function, TestArguments, TestContext) -> ()
+
+
+public struct TestContext: MutatingContext {
+  public let _bridged: BridgedContext
+  public let notifyInstructionChanged: (Instruction) -> () = { inst in }
+
+  fileprivate init(bridged: BridgedContext) { self._bridged = bridged}
+}
+
+/// Wraps the arguments specified in the specify_test instruction.
+public struct TestArguments {
+  public var bridged: BridgedTestArguments
+  fileprivate init(bridged: BridgedTestArguments) {
+    self.bridged = bridged
+  }
+
+  public var hasUntaken: Bool { bridged.hasUntaken() }
+  public func takeString() -> StringRef { StringRef(bridged: bridged.takeString()) }
+  public func takeBool() -> Bool { bridged.takeBool() }
+  public func takeInt() -> Int { bridged.takeInt() }
+  public func takeOperand() -> Operand { Operand(bridged: bridged.takeOperand()) }
+  public func takeValue() -> Value { bridged.takeValue().value }
+  public func takeInstruction() -> Instruction { bridged.takeInstruction().instruction }
+  public func takeArgument() -> Argument { bridged.takeArgument().argument }
+  public func takeBlock() -> BasicBlock { bridged.takeBlock().block }
+  public func takeFunction() -> Function { bridged.takeFunction().function }
+}
+
+extension BridgedTestArguments {
+  public var native: TestArguments { TestArguments(bridged: self) }
+}
+
+/// Registration of each test in the SIL module.
+public func registerTests() {
+  // Register each test.
+  registerTests(
+    parseTestSpecificationTest,
+    smallProjectionPathTest,
+    getAccessBaseTest,
+    borrowIntroducersTest,
+    enclosingValuesTest,
+    forwardingDefUseTest,
+    forwardingUseDefTest
+  )
+
+  registerTestThunk(testThunk)
+}
+
+private func registerTests(_ tests: Test...) {
+  tests.forEach { registerTest($0) }
+}
+
+private func registerTest(_ test: Test) {
+  test.name._withBridgedStringRef { ref in
+    registerTest(ref, castToOpaquePointer(fromInvocation: test.invocation))
+  }
+}
+
+/// The function called by the swift::test::FunctionTest which invokes the
+/// actual test function.
+///
+/// This function is necessary because tests need to be written in terms of
+/// native Swift types (Function, TestArguments, TestContext)
+/// rather than their bridged variants, but such a function isn't representable
+/// in C++. This thunk unwraps the bridged types and invokes the real function.
+private func testThunk(
+  _ erasedInvocation: UnsafeMutableRawPointer,
+  _ function: BridgedFunction,
+  _ arguments: BridgedTestArguments,
+  _ bridgedContext: BridgedContext) {
+  let invocation = castToInvocation(fromOpaquePointer: erasedInvocation)
+  let context = TestContext(bridged: bridgedContext)
+  invocation(function.function, arguments.native, context)
+}
+
+/// Bitcast a thin test closure to void *.
+///
+/// Needed so that the closure can be represented in C++ for storage in the test
+/// registry.
+private func castToOpaquePointer(fromInvocation invocation: TestInvocation) -> UnsafeMutableRawPointer {
+  return unsafeBitCast(invocation, to: UnsafeMutableRawPointer.self)
+}
+
+/// Bitcast a void * to a thin test closure.
+///
+/// Needed so that the closure stored in the C++ test registry can be invoked via the testThunk.
+private func castToInvocation(fromOpaquePointer erasedInvocation: UnsafeMutableRawPointer) -> TestInvocation {
+  return unsafeBitCast(erasedInvocation, to: TestInvocation.self)
+}
+
+// Arguments:
+// - string: list of characters, each of which specifies subsequent arguments
+//           - A: (block) argument
+//           - F: function
+//           - B: block
+//           - I: instruction
+//           - V: value
+//           - O: operand
+//           - b: boolean
+//           - u: unsigned
+//           - s: string
+// - ...
+// - an argument of the type specified in the initial string
+// - ...
+// Dumps:
+// - for each argument (after the initial string)
+//   - its type
+//   - something to identify the instance (mostly this means calling dump)
+let parseTestSpecificationTest = Test("test_specification_parsing") { function, arguments, context in
+  let expectedFields = arguments.takeString()
+  for expectedField in expectedFields.string {
+    switch expectedField {
+    case "A":
+      let argument = arguments.takeArgument()
+      print("argument:\n\(argument)")
+    case "F":
+      let function = arguments.takeFunction()
+      print("function: \(function.name)")
+    case "B":
+      let block = arguments.takeBlock()
+      print("block:\n\(block)")
+    case "I":
+      let instruction = arguments.takeInstruction()
+      print("instruction: \(instruction)")
+    case "V":
+      let value = arguments.takeValue()
+      print("value: \(value)")
+    case "O":
+      let operand = arguments.takeOperand()
+      print("operand: \(operand)")
+    case "u":
+      let u = arguments.takeInt()
+      print("uint: \(u)")
+    case "b":
+      let b = arguments.takeBool()
+      print("bool: \(b)")
+    case "s":
+      let s = arguments.takeString()
+      print("string: \(s)")
+    default:
+      fatalError("unknown field type was expected?!");
+    }
+  }
+}
diff --git a/SwiftCompilerSources/Sources/Optimizer/Utilities/Verifier.swift b/SwiftCompilerSources/Sources/SIL/Utilities/Verifier.swift
similarity index 83%
rename from SwiftCompilerSources/Sources/Optimizer/Utilities/Verifier.swift
rename to SwiftCompilerSources/Sources/SIL/Utilities/Verifier.swift
index 42f5bba0f7099..6fbd6c5b96893 100644
--- a/SwiftCompilerSources/Sources/Optimizer/Utilities/Verifier.swift
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/Verifier.swift
@@ -10,24 +10,29 @@
 //
 //===----------------------------------------------------------------------===//
 
-import SIL
-import OptimizerBridging
+import SILBridging
 
+/// To add verification for a specific instruction, let the instruction class conform to
+/// this protocol and implement the `verify` method.
 private protocol VerifiableInstruction : Instruction {
-  func verify(_ context: FunctionPassContext)
+  func verify(_ context: VerifierContext)
 }
 
 private func require(_ condition: Bool, _ message: @autoclosure () -> String, atInstruction: Instruction? = nil) {
   if !condition {
     let msg = message()
     msg._withBridgedStringRef { stringRef in
-      verifierError(stringRef, atInstruction.bridged, Optional<Argument>.none.bridged)
+      BridgedVerifier.verifierError(stringRef, atInstruction.bridged, Optional<Argument>.none.bridged)
     }
   }
 }
 
+struct VerifierContext: Context {
+  let _bridged: BridgedContext
+}
+
 extension Function {
-  func verify(_ context: FunctionPassContext) {
+  func verify(_ context: VerifierContext) {
     for block in blocks {
       for arg in block.arguments {
         arg.verify(context)
@@ -56,23 +61,24 @@ private extension Instruction {
 
   func checkGuaranteedResults() {
     for result in results where result.ownership == .guaranteed {
-      require(BeginBorrowValue(result) != nil || self is ForwardingInstruction,
+      require(BeginBorrowValue(result) != nil || self is ForwardingInstruction || result.isGuaranteedApplyResult,
               "\(result) must either be a BeginBorrowValue or a ForwardingInstruction")
     }
   }
 }
 
 private extension Argument {
-  func verify(_ context: FunctionPassContext) {
+  func verify(_ context: VerifierContext) {
     if let phi = Phi(self), phi.value.ownership == .guaranteed {
 
       phi.verifyBorrowedFromUse()
 
-      require(phi.isReborrow == phi.hasBorrowEndingUse ||
-              // In a dead-end block an end_borrow might have been deleted.
-              // TODO: this check is not needed anymore once we have complete OSSA lifetimes.
-              (isReborrow && context.deadEndBlocks.isDeadEnd(parentBlock)),
+      // TODO: enable this check once we have complete OSSA lifetimes.
+      // In a dead-end block an end_borrow might have been deleted.
+      /*
+      require(phi.isReborrow == phi.hasBorrowEndingUse,
               "\(self) has stale reborrow flag");
+      */
     }
   }
 
@@ -95,7 +101,7 @@ private extension Phi {
 }
 
 extension BorrowedFromInst : VerifiableInstruction {
-  func verify(_ context: FunctionPassContext) {
+  func verify(_ context: VerifierContext) {
 
     for ev in enclosingValues {
       require(ev.isValidEnclosingValueInBorrowedFrom, "invalid enclosing value in borrowed-from: \(ev)")
@@ -135,7 +141,7 @@ private extension Value {
 }
 
 extension LoadBorrowInst : VerifiableInstruction {
-  func verify(_ context: FunctionPassContext) {
+  func verify(_ context: VerifierContext) {
     if isUnchecked {
       return
     }
@@ -148,16 +154,26 @@ extension LoadBorrowInst : VerifiableInstruction {
   }
 }
 
+extension VectorBaseAddrInst : VerifiableInstruction {
+  func verify(_ context: VerifierContext) {
+    require(vector.type.isBuiltinFixedArray,
+            "vector operand of vector_element_addr must be a Builtin.FixedArray")
+    require(type == vector.type.builtinFixedArrayElementType(in: parentFunction,
+                                                             maximallyAbstracted: true).addressType,
+            "result of vector_element_addr has wrong type")
+  }
+}
+
 // Used to check if any instruction is mutating the memory location within the liverange of a `load_borrow`.
 // Note that it is not checking if an instruction _may_ mutate the memory, but it's checking if any instruction
 // _definitely_ will mutate the memory.
 // Otherwise the risk would be too big for false alarms. It also means that this verification is not perfect and
 // might miss some subtle violations.
 private struct MutatingUsesWalker : AddressDefUseWalker {
-  let context: FunctionPassContext
+  let context: VerifierContext
   var mutatingInstructions: InstructionSet
 
-  init(_ context: FunctionPassContext) {
+  init(_ context: VerifierContext) {
     self.context = context
     self.mutatingInstructions = InstructionSet(context)
   }
@@ -230,7 +246,7 @@ private extension Operand {
     case let copy as SourceDestAddrInstruction:
       if self == copy.destinationOperand {
         return true
-      } else if self == copy.sourceOperand && copy.isTakeOfSrc {
+      } else if self == copy.sourceOperand && copy.isTakeOfSource {
         return true
       }
       return false
@@ -258,9 +274,9 @@ private extension Operand {
 }
 
 func registerVerifier() {
-  BridgedUtilities.registerVerifier(
-    { (bridgedCtxt: BridgedPassContext, bridgedFunction: BridgedFunction) in
-      let context = FunctionPassContext(_bridged: bridgedCtxt)
+  BridgedVerifier.registerVerifier(
+    { (bridgedCtxt: BridgedContext, bridgedFunction: BridgedFunction) in
+      let context = VerifierContext(_bridged: bridgedCtxt)
       bridgedFunction.function.verify(context)
     }
   )
diff --git a/SwiftCompilerSources/Sources/SIL/Utilities/WalkUtils.swift b/SwiftCompilerSources/Sources/SIL/Utilities/WalkUtils.swift
index a5ecef2512688..59c27a7cf291a 100644
--- a/SwiftCompilerSources/Sources/SIL/Utilities/WalkUtils.swift
+++ b/SwiftCompilerSources/Sources/SIL/Utilities/WalkUtils.swift
@@ -39,10 +39,11 @@ public enum WalkResult {
 }
 
 extension Sequence {
+  // Walk each element until the walk aborts.
   public func walk(
-    _ predicate: (Element) throws -> WalkResult
+    _ walker: (Element) throws -> WalkResult
   ) rethrows -> WalkResult {
-    return try contains { try predicate($0) == .abortWalk } ? .abortWalk : .continueWalk
+    return try contains { try walker($0) == .abortWalk } ? .abortWalk : .continueWalk
   }
 }
 
@@ -508,6 +509,12 @@ extension AddressDefUseWalker {
       } else {
         return unmatchedPath(address: operand, path: path)
       }
+    case let vba as VectorBaseAddrInst:
+      if let path = path.popIfMatches(.vectorBase, index: 0) {
+        return walkDownUses(ofAddress: vba, path: path)
+      } else {
+        return unmatchedPath(address: operand, path: path)
+      }
     case is InitEnumDataAddrInst, is UncheckedTakeEnumDataAddrInst:
       let ei = instruction as! SingleValueInstruction
       if let path = path.popIfMatches(.enumCase, index: (instruction as! EnumInstruction).caseIndex) {
@@ -530,8 +537,12 @@ extension AddressDefUseWalker {
         return walkDownUses(ofAddress: ia, path: subPath.push(.anyIndexedElement, index: 0))
       }
       return walkDownUses(ofAddress: ia, path: path)
-    case let mmc as MarkUnresolvedNonCopyableValueInst:
-      return walkDownUses(ofAddress: mmc, path: path)
+    case is MarkUninitializedInst,
+         is MoveOnlyWrapperToCopyableAddrInst,
+         is CopyableToMoveOnlyWrapperAddrInst,
+         is MarkUnresolvedNonCopyableValueInst,
+         is DropDeinitInst:
+      return walkDownUses(ofAddress: instruction as! SingleValueInstruction, path: path)
     case let ba as BeginAccessInst:
       // Don't treat `end_access` as leaf-use. Just ignore it.
       return walkDownNonEndAccessUses(of: ba, path: path)
@@ -813,24 +824,27 @@ extension AddressUseDefWalker {
       return walkUp(address: sea.struct, path: path.push(.structField, index: sea.fieldIndex))
     case let tea as TupleElementAddrInst:
       return walkUp(address: tea.tuple, path: path.push(.tupleField, index: tea.fieldIndex))
+    case let vba as VectorBaseAddrInst:
+      return walkUp(address: vba.vector, path: path.push(.vectorBase, index: 0))
     case let ida as InitEnumDataAddrInst:
       return walkUp(address: ida.operand.value, path: path.push(.enumCase, index: ida.caseIndex))
     case let uteda as UncheckedTakeEnumDataAddrInst:
       return walkUp(address: uteda.operand.value, path: path.push(.enumCase, index: uteda.caseIndex))
     case is InitExistentialAddrInst, is OpenExistentialAddrInst:
       return walkUp(address: (def as! Instruction).operands[0].value, path: path.push(.existential, index: 0))
-    case is BeginAccessInst, is MarkUnresolvedNonCopyableValueInst:
-      return walkUp(address: (def as! Instruction).operands[0].value, path: path)
     case let ia as IndexAddrInst:
       if let idx = ia.constantIndex {
         return walkUp(address: ia.base, path: path.push(.indexedElement, index: idx))
       } else {
         return walkUp(address: ia.base, path: path.push(.anyIndexedElement, index: 0))
       }
-    case is MarkDependenceInst, is MarkUninitializedInst:
-      return walkUp(address: (def as! Instruction).operands[0].value, path: path)
-    case is MoveOnlyWrapperToCopyableAddrInst,
-         is CopyableToMoveOnlyWrapperAddrInst:
+    case is BeginAccessInst,
+         is MarkDependenceInst,
+         is MarkUninitializedInst,
+         is MoveOnlyWrapperToCopyableAddrInst,
+         is CopyableToMoveOnlyWrapperAddrInst,
+         is MarkUnresolvedNonCopyableValueInst,
+         is DropDeinitInst:
       return walkUp(address: (def as! Instruction).operands[0].value, path: path)
   default:
       return rootDef(address: def, path: path)
diff --git a/SwiftCompilerSources/Sources/SIL/VTable.swift b/SwiftCompilerSources/Sources/SIL/VTable.swift
index 89dabfdef7d48..7f10933291491 100644
--- a/SwiftCompilerSources/Sources/SIL/VTable.swift
+++ b/SwiftCompilerSources/Sources/SIL/VTable.swift
@@ -87,6 +87,7 @@ public struct VTable : CustomStringConvertible, NoReflectionChildren {
 
   public var `class`: ClassDecl { bridged.getClass().getAs(ClassDecl.self) }
 
+  /// Returns the concrete class type if this is a specialized vTable.
   public var specializedClassType: Type? { bridged.getSpecializedClassType().typeOrNil }
 
   public var isSpecialized: Bool { specializedClassType != nil }
diff --git a/SwiftCompilerSources/Sources/SIL/Value.swift b/SwiftCompilerSources/Sources/SIL/Value.swift
index 829a3cd41b048..a346cb621ba80 100644
--- a/SwiftCompilerSources/Sources/SIL/Value.swift
+++ b/SwiftCompilerSources/Sources/SIL/Value.swift
@@ -243,9 +243,9 @@ extension Value {
   /// struct S { var c1: C; var c2: C }
   /// let s: S
   ///
-  /// `s.allContainedAddresss` refers to `s.c1.x`, `s.c1.y`, `s.c2.x` and `s.c2.y`
+  /// `s.allContainedAddresses` refers to `s.c1.x`, `s.c1.y`, `s.c2.x` and `s.c2.y`
   ///
-  public var allContainedAddresss: ProjectedValue {
+  public var allContainedAddresses: ProjectedValue {
     if type.isAddress {
       // This is the regular case: the path selects any sub-fields of an address.
       return at(SmallProjectionPath(.anyValueFields))
@@ -298,6 +298,10 @@ public final class Undef : Value {
   public var hasTrivialNonPointerType: Bool { false }
 
   public var isLexical: Bool { false }
+
+  public static func get(type: Type, _ context: some MutatingContext) -> Undef {
+    context._bridged.getSILUndef(type.bridged).value as! Undef
+  }
 }
 
 final class PlaceholderValue : Value {
diff --git a/SwiftCompilerSources/Sources/SIL/WitnessTable.swift b/SwiftCompilerSources/Sources/SIL/WitnessTable.swift
index 88df8fc194ab8..cb779bb033e6b 100644
--- a/SwiftCompilerSources/Sources/SIL/WitnessTable.swift
+++ b/SwiftCompilerSources/Sources/SIL/WitnessTable.swift
@@ -31,7 +31,7 @@ public struct WitnessTable : CustomStringConvertible, NoReflectionChildren {
     case associatedType(requirement: AssociatedTypeDecl, witness: CanonicalType)
 
     /// A witness table entry describing the witness for an associated type's protocol requirement.
-    case associatedConformance(requirement: CanonicalType, substType: CanonicalType, witness: Conformance)
+    case associatedConformance(requirement: CanonicalType, witness: Conformance)
 
     /// A witness table entry referencing the protocol conformance for a refined base protocol.
     case baseProtocol(requirement: ProtocolDecl, witness: Conformance)
@@ -48,7 +48,6 @@ public struct WitnessTable : CustomStringConvertible, NoReflectionChildren {
                                witness: CanonicalType(bridged: bridged.getAssociatedTypeWitness()))
       case .associatedConformance:
         self = .associatedConformance(requirement: CanonicalType(bridged: bridged.getAssociatedConformanceRequirement()),
-                                      substType: CanonicalType(bridged: bridged.getAssociatedConformanceSubstType()),
                                       witness: Conformance(bridged: bridged.getAssociatedConformanceWitness()))
       case .baseProtocol:
         self = .baseProtocol(requirement: bridged.getBaseProtocolRequirement().getAs(ProtocolDecl.self),
@@ -71,9 +70,8 @@ public struct WitnessTable : CustomStringConvertible, NoReflectionChildren {
                                                      OptionalBridgedFunction(obj: witness?.bridged.obj))
       case .associatedType(let requirement, let witness):
         return BridgedWitnessTableEntry.createAssociatedType(requirement.bridged, witness.bridged)
-      case .associatedConformance(let requirement, let substType, let witness):
+      case .associatedConformance(let requirement, let witness):
         return BridgedWitnessTableEntry.createAssociatedConformance(requirement.bridged,
-                                                                    substType.bridged,
                                                                     witness.bridged)
       case .baseProtocol(let requirement, let witness):
         return BridgedWitnessTableEntry.createBaseProtocol(requirement.bridged, witness.bridged)
@@ -113,6 +111,9 @@ public struct WitnessTable : CustomStringConvertible, NoReflectionChildren {
 
   public var isDefinition: Bool { !bridged.isDeclaration() }
 
+  // True, if this is a specialized witness table (currently only used in embedded mode).
+  public var isSpecialized: Bool { bridged.isSpecialized() }
+
   public var description: String {
     return String(taking: bridged.getDebugDescription())
   }
diff --git a/benchmark/CMakeLists.txt b/benchmark/CMakeLists.txt
index bf43145b7c690..be40f43902092 100644
--- a/benchmark/CMakeLists.txt
+++ b/benchmark/CMakeLists.txt
@@ -220,12 +220,24 @@ set(SWIFT_BENCH_MODULES
 
 set(SWIFT_MULTISOURCE_SWIFT_BENCHES
   multi-source/PrimsSplit
+  multi-source/Monoids
 )
 
 set(PrimsSplit_sources
     multi-source/PrimsSplit/Prims.swift
     multi-source/PrimsSplit/Prims_main.swift)
 
+set(Monoids_sources
+    multi-source/Monoids/Automaton.swift
+    multi-source/Monoids/Benchmark.swift
+    multi-source/Monoids/Enumeration.swift
+    multi-source/Monoids/Monoids.swift
+    multi-source/Monoids/Presentation.swift
+    multi-source/Monoids/RewritingSystem.swift
+    multi-source/Monoids/Solver.swift
+    multi-source/Monoids/Strategy.swift
+    multi-source/Monoids/Trie.swift)
+
 set(BENCH_DRIVER_LIBRARY_FLAGS)
 if (SWIFT_RUNTIME_ENABLE_LEAK_CHECKER)
   set(BENCH_DRIVER_LIBRARY_FLAGS -DSWIFT_RUNTIME_ENABLE_LEAK_CHECKER)
diff --git a/benchmark/Package.swift b/benchmark/Package.swift
index 4715683480358..32afaae13b436 100644
--- a/benchmark/Package.swift
+++ b/benchmark/Package.swift
@@ -178,17 +178,22 @@ targets += multiSourceLibraries.map { lib in
     dependencies: [
       .target(name: "TestsUtils")
     ],
-    path: lib.parentSubDir)
+    path: "\(lib.parentSubDir)/\(lib.name)")
 }
 
 //===---
 // Top Level Definition
 //
 
-let p = Package(
+var p = Package(
   name: "swiftbench",
   products: products,
   targets: targets,
   swiftLanguageVersions: [.v4],
   cxxLanguageStandard: .cxx20
 )
+
+// Let's build for Swift 5.5-aligned runtimes.
+#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS)
+p.platforms = [.macOS(.v12), .iOS(.v15), .watchOS(.v8), .tvOS(.v15)]
+#endif
diff --git a/benchmark/cmake/modules/AddSwiftBenchmarkSuite.cmake b/benchmark/cmake/modules/AddSwiftBenchmarkSuite.cmake
index 7c5387bb5ccd6..d7b7803adcee2 100644
--- a/benchmark/cmake/modules/AddSwiftBenchmarkSuite.cmake
+++ b/benchmark/cmake/modules/AddSwiftBenchmarkSuite.cmake
@@ -363,6 +363,10 @@ function (swift_benchmark_compile_archopts)
     list(APPEND common_options "-g")
   endif()
 
+  if("${optflag}" STREQUAL "Onone")
+    list(APPEND common_options "-DDEBUG")
+  endif()
+
   if (is_darwin)
     list(APPEND common_options
       "-I" "${srcdir}/utils/ObjectiveCTests"
@@ -400,6 +404,10 @@ function (swift_benchmark_compile_archopts)
       "-target" "${target}"
       "-${driver_opt}")
 
+  if(${optflag} STREQUAL "Onone")
+    list(APPEND common_options_driver "-DDEBUG")
+  endif()
+
   if(SWIFT_BENCHMARK_GENERATE_DEBUG_INFO)
     list(APPEND common_options_driver "-g")
   endif()
@@ -716,9 +724,6 @@ function(swift_benchmark_compile)
 
   if(NOT SWIFT_BENCHMARK_BUILT_STANDALONE)
     set(stdlib_dependencies "swift-frontend" "swiftCore-${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
-    if((SWIFT_HOST_VARIANT_SDK IN_LIST SWIFT_DARWIN_PLATFORMS) AND SWIFT_BUILD_SDK_OVERLAY)
-      list(APPEND stdlib_dependencies "swiftDarwin-${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
-    endif()
     foreach(stdlib_dependency ${UNIVERSAL_LIBRARY_NAMES_${SWIFT_BENCHMARK_COMPILE_PLATFORM}})
       string(FIND "${stdlib_dependency}" "Unittest" find_output)
       if("${find_output}" STREQUAL "-1")
diff --git a/benchmark/multi-source/Monoids/Automaton.swift b/benchmark/multi-source/Monoids/Automaton.swift
new file mode 100644
index 0000000000000..7c75553692c65
--- /dev/null
+++ b/benchmark/multi-source/Monoids/Automaton.swift
@@ -0,0 +1,153 @@
+/// This file implements an algorithm to compute the number of elements in a
+/// monoid (or determine it is infinite), given a complete presentation.
+
+/// A finite state automaton, given by a set of vertices and edges.
+struct Automaton {
+  var states: [Word] = []
+  var transitions: [(Word, Symbol, Word)] = []
+}
+
+extension Automaton {
+  var hasStar: Bool {
+    for state in states {
+      var visited = Set<Word>()
+
+      func rec(_ state: Word) -> Bool {
+        for (from, _, to) in transitions {
+          if from == state {
+            if visited.contains(to) {
+              return true
+            } else {
+              visited.insert(to)
+              if rec(to) { return true }
+              visited.remove(to)
+            }
+          }
+        }
+
+        return false
+      }
+
+      visited.insert(state)
+      if rec(state) { return true }
+      visited.remove(state)
+    }
+
+    return false
+  }
+
+  /// If this automaton is star-free, count the number of unique words accepted.
+  var countWords: Int {
+    func R(_ q: Word) -> [Word] {
+      var result: [Word] = []
+
+      for (from, _, to) in transitions {
+        if to == q {
+          result.append(from)
+        }
+      }
+
+      return result
+    }
+
+    func T(_ q: Word, _ p: Word) -> Int {
+      var letters = Set<Symbol>()
+      for (from, x, to) in transitions {
+        if from == q && to == p {
+          letters.insert(x)
+        }
+      }
+      return letters.count
+    }
+
+    func N(_ q: Word) -> Int {
+      if q == [] {
+        return 1
+      }
+
+      var result = 0
+      for p in R(q) {
+        result += N(p) * T(p, q)
+      }
+      return result
+    }
+
+    var result = 0
+
+    for q in states {
+      result += N(q)
+    }
+
+    return result
+  }
+}
+
+extension RewritingSystem {
+  /// Constructs an automaton to recognize the complement of this regular set:
+  ///
+  ///   .*(x1|x2|...).*
+  ///
+  /// where 'words' is [x1, x2, ...].
+  ///
+  /// This is Lemma 2.1.3 in:
+  ///
+  /// String Rewriting Systems, R.V. Book, F. Otto 1993. Springer New York.
+  func buildAutomaton() -> Automaton {
+    // Proper prefixes of each word.
+    var prefixes = Set<Word>()
+
+    var result = Automaton()
+
+    func isIrreducible(_ word: Word) -> Bool {
+      return reduceOne(word) == nil
+    }
+
+    prefixes.insert([])
+    for rule in presentation.rules {
+      let word = rule.lhs
+      for i in 0 ..< word.count {
+        let prefix = Word(word[0 ..< i])
+        prefixes.insert(prefix)
+      }
+    }
+
+    result.states = prefixes.sorted { compare($0, $1, order: .shortlex) == .lessThan }
+
+    for prefix in prefixes {
+      for x in 0 ..< UInt8(alphabet) {
+        let word = prefix + [x]
+
+        if prefixes.contains(word) {
+          result.transitions.append((prefix, x, word))
+          continue
+        }
+
+        if !isIrreducible(word) {
+          continue
+        }
+
+        for i in 1 ... word.count {
+          let suffix = Word(word[i...])
+
+          if prefixes.contains(suffix) {
+            result.transitions.append((prefix, x, suffix))
+            break
+          }
+        }
+      }
+    }
+
+    return result
+  }
+
+  /// Returns the number of irreducible words in this monoid presentation, or
+  /// nil if this set is infinite.
+  var cardinality: Int? {
+    precondition(state == .complete)
+    let automaton = buildAutomaton()
+    if automaton.hasStar {
+      return nil
+    }
+    return automaton.countWords
+  }
+}
diff --git a/benchmark/multi-source/Monoids/Benchmark.swift b/benchmark/multi-source/Monoids/Benchmark.swift
new file mode 100644
index 0000000000000..4d391af453f67
--- /dev/null
+++ b/benchmark/multi-source/Monoids/Benchmark.swift
@@ -0,0 +1,14 @@
+import TestsUtils
+
+public let benchmarks = [
+  BenchmarkInfo(
+    name: "Monoids",
+    runFunction: run_Monoids,
+    tags: [.algorithm, .miniapplication, .long])
+]
+
+func run_Monoids(_ n: Int) async {
+  for _ in 0 ... n {
+    await run(output: false)
+  }
+}
diff --git a/benchmark/multi-source/Monoids/Enumeration.swift b/benchmark/multi-source/Monoids/Enumeration.swift
new file mode 100644
index 0000000000000..d51b8e7619cde
--- /dev/null
+++ b/benchmark/multi-source/Monoids/Enumeration.swift
@@ -0,0 +1,171 @@
+/// This file implements algorithms for enumerating all monoid presentations
+/// up to a given length.
+
+func nextSymbol(_ s: inout Symbol, alphabet: Int) -> Bool {
+  precondition(alphabet > 0)
+  if s == alphabet - 1 {
+    s = 0
+    return true
+  }
+  s += 1
+  return false
+}
+
+func nextWord(_ word: inout Word, alphabet: Int) -> Bool {
+  var carry = true
+  for i in word.indices.reversed() {
+    carry = nextSymbol(&word[i], alphabet: alphabet)
+    if !carry { break }
+  }
+  return carry
+}
+
+func nextRule(_ rule: inout Rule, alphabet: Int) -> Bool {
+  if nextWord(&rule.rhs, alphabet: alphabet) {
+    rule.rhs = Word(repeating: 0, count: rule.rhs.count)
+    if nextWord(&rule.lhs, alphabet: alphabet) {
+      rule.lhs = Word(repeating: 0, count: rule.lhs.count)
+      return true
+    }
+  }
+  return false
+}
+
+func nextPresentation(_ p: inout Presentation, alphabet: Int) -> Bool {
+  precondition(!p.rules.isEmpty)
+  var carry = true
+  for i in p.rules.indices.reversed() {
+    carry = nextRule(&p.rules[i], alphabet: alphabet)
+    if !carry { break }
+  }
+  return carry
+}
+
+struct RuleShape {
+  var lhs: Int
+  var rhs: Int
+
+  var rule: Rule {
+    return Rule(lhs: Word(repeating: 0, count: lhs),
+                rhs: Word(repeating: 0, count: rhs))
+  }
+}
+
+struct PresentationShape {
+  var rules: [RuleShape]
+
+  func presentation(alphabet: Int) -> Presentation {
+    return Presentation(alphabet: alphabet,
+                        rules: rules.map { $0.rule })
+  }
+}
+
+func enumerateAll(alphabet: Int, shapes: [PresentationShape], output: Bool)
+    -> [Presentation] {
+  var filteredLHS = 0
+  var filteredRHS = 0
+  var filteredSymmetry = 0
+  var total = 0
+
+  var instances: [Presentation] = []
+  var unique: Set<Presentation> = []
+
+  let perms = allPermutations(alphabet)
+
+  for shape in shapes {
+    var p = shape.presentation(alphabet: alphabet)
+    var done = false
+
+loop: while !done {
+      defer {
+        done = nextPresentation(&p, alphabet: alphabet)
+      }
+
+      total += 1
+
+      for n in 0 ..< p.rules.count - 1 {
+        if compare(p.rules[n].lhs, p.rules[n + 1].lhs, order: .shortlex) != .lessThan {
+          filteredLHS += 1
+          continue loop
+        }
+      }
+
+      for rule in p.rules {
+        precondition(rule.rhs.count <= rule.lhs.count)
+        if compare(rule.rhs, rule.lhs, order: .shortlex) != .lessThan {
+          filteredRHS += 1
+          continue loop
+        }
+      }
+
+      if unique.contains(p) {
+        filteredSymmetry += 1
+        continue
+      }
+
+      for perm in perms {
+        let permuted = p.permuted(perm)
+        unique.insert(permuted.sorted(order: .shortlex))
+      }
+
+      instances.append(p)
+    }
+  }
+
+  if output {
+    print("# Total \(total)")
+    print("# Discarded lhs:\(filteredLHS),rhs:\(filteredRHS),"
+          + "symmetry:\(filteredSymmetry)")
+  }
+
+  return instances
+}
+
+func ruleShapes(_ n: Int) -> [RuleShape] {
+  precondition(n > 0)
+  var result: [RuleShape] = []
+  for i in 0 ..< n {
+    let j = n - i
+
+    // Don't consider rules with a shorter left-hand side.
+    if j < i { continue }
+
+    // Don't consider rules of the form x=1 or x=y where x, y are generators.
+    if j == 1 && i <= 1 { continue }
+
+    result.append(RuleShape(lhs: j, rhs: i))
+  }
+  return result
+}
+
+func presentationShapes(rules: Int, ofLength n: Int) -> [PresentationShape] {
+  precondition(n > 0)
+  precondition(rules > 0)
+
+  if rules == 1 {
+    return ruleShapes(n).map {
+      PresentationShape(rules: [$0])
+    }
+  }
+
+  var result: [PresentationShape] = []
+  for i in 1 ..< n {
+    let next = presentationShapes(rules: rules - 1, ofLength: i)
+    for x in ruleShapes(n - i) {
+      for y in next {
+        if x.lhs <= y.rules.first!.lhs {
+          result.append(PresentationShape(rules: [x] + y.rules))
+        }
+      }
+    }
+  }
+  return result
+}
+
+func presentationShapes(rules: Int, upToLength n: Int) -> [PresentationShape] {
+  var shapes: [PresentationShape] = []
+  for i in 1 ... n {
+    shapes.append(contentsOf: presentationShapes(rules: rules, ofLength: i))
+  }
+  return shapes
+}
diff --git a/benchmark/multi-source/Monoids/Monoids.swift b/benchmark/multi-source/Monoids/Monoids.swift
new file mode 100644
index 0000000000000..dc9d1097e2027
--- /dev/null
+++ b/benchmark/multi-source/Monoids/Monoids.swift
@@ -0,0 +1,33 @@
+/// This is the main entry point.
+///
+/// We enumerate all 2-generator, 2-relation monoids of length up to 10:
+///
+///   <a, b | u=v, w=x>  where |u| + |v| + |w| + |x| <= 10
+///
+/// We attempt to build an FCRS for each one by trying various strategies,
+/// which ultimately succeeds for all but three instances.
+func run(output: Bool) async {
+  let shapes = presentationShapes(rules: 2, upToLength: 10)
+
+  let alphabet = 2
+  let instances = enumerateAll(alphabet: alphabet, shapes: shapes, output: output)
+
+  var solver = Solver(alphabet: alphabet, instances: instances, output: output)
+  await solver.solve()
+
+  // These we know we can't solve.
+  let expectUnsolved: [Presentation] = ["bab=aaa,bbbb=1", "aaaa=1,abbba=b", "aaa=a,abba=bb"]
+
+  // Make sure everything else was solved.
+  let unsolved = solver.subset.map { instances[$0] }
+  if unsolved != expectUnsolved {
+    fatalError("Expected \(expectUnsolved), but got \(unsolved)")
+  }
+
+  // Also check finite monoid results.
+  let expectFinite = [1: 1188, 2: 2059, 3: 1233, 4: 1644, 5: 1019, 6: 1630, 7: 686, 8: 884, 9: 493, 10: 615, 11: 191, 12: 317, 13: 79, 14: 134, 15: 62, 16: 158, 17: 16, 18: 60, 19: 2, 20: 52, 21: 38, 22: 12, 24: 31, 25: 5, 26: 11, 27: 42, 28: 10, 30: 52, 32: 5, 34: 8, 36: 17, 39: 4, 42: 4, 44: 8, 48: 12, 50: 12, 52: 4, 55: 4, 56: 8, 60: 18, 64: 14, 81: 6, 84: 22, 96: 1, 100: 4, 105: 2, 120: 7, 129: 2, 147: 6, 160: 2, 165: 2, 192: 2, 195: 2, 320: 2, 324: 2, 339: 4, 605: 2, 1083: 2]
+  let finite = solver.finite
+  if finite != expectFinite {
+    fatalError("Expected \(expectFinite), but got \(finite)")
+  }
+}
diff --git a/benchmark/multi-source/Monoids/Presentation.swift b/benchmark/multi-source/Monoids/Presentation.swift
new file mode 100644
index 0000000000000..356c8bc78131d
--- /dev/null
+++ b/benchmark/multi-source/Monoids/Presentation.swift
@@ -0,0 +1,369 @@
+/// This file defines the data types we use for words, rules, and
+/// monoid presentations. Also, a few other fundamental algorithms
+/// for working with permutations and reduction orders.
+
+typealias Symbol = UInt8
+
+let symbols: [Character] = ["a", "b", "c"]
+
+func printSymbol(_ s: Symbol) -> Character {
+  return symbols[Int(s)]
+}
+
+func parseSymbol(_ c: Character) -> Symbol {
+  return Symbol(symbols.firstIndex(of: c)!)
+}
+
+typealias Word = [Symbol]
+
+func printWord(_ word: Word) -> String {
+  if word.isEmpty { return "1" }
+  return String(word.map { printSymbol($0) })
+}
+
+func parseWord(_ str: String) -> Word {
+  if str == "" || str == "1" { return [] }
+  return str.map { parseSymbol($0) }
+}
+
+struct Rule: Hashable {
+  var lhs: Word
+  var rhs: Word
+}
+
+extension Rule: ExpressibleByStringLiteral, CustomStringConvertible {
+  init(_ str: String) {
+    let pair = str.split(separator: "=")
+    precondition(pair.count == 2)
+    self.lhs = parseWord(String(pair[0]))
+    self.rhs = parseWord(String(pair[1]))
+  }
+
+  init(stringLiteral: String) {
+    self.init(stringLiteral)
+  }
+
+  var description: String {
+    return "\(printWord(lhs))=\(printWord(rhs))"
+  }
+}
+
+struct Presentation: Hashable {
+  var alphabet: Int
+  var rules: [Rule]
+
+  var longestRule: Int {
+    var result = 0
+    for rule in rules {
+      result = max(result, rule.lhs.count)
+      result = max(result, rule.rhs.count)
+    }
+    return result
+  }
+}
+
+func printRules(_ rules: [Rule]) -> String {
+  return rules.map { $0.description }.joined(separator: ",")
+}
+
+extension Presentation: ExpressibleByStringLiteral, CustomStringConvertible {
+  init(_ str: String) {
+    self.alphabet = 2
+    self.rules = str.split(separator: ",").map { Rule(String($0)) }
+  }
+
+  init(stringLiteral: String) {
+    self.init(stringLiteral)
+  }
+
+  var description: String {
+    return printRules(rules)
+  }
+}
+
+typealias Permutation = [Int]
+
+func identityPermutation(_ n: Int) -> Permutation {
+  return Permutation(0 ..< n)
+}
+
+func inversePermutation(_ perm: Permutation) -> Permutation {
+  var result = Permutation(repeating: 0, count: perm.count)
+  for (i, j) in perm.enumerated() {
+    result[j] = i
+  }
+  return result
+}
+
+// TAOCP 4A 7.2.1.2 Algorithm L
+func nextPermutation(_ perm: inout Permutation) -> Bool {
+  var j = perm.count - 2
+  while j >= 0 && perm[j] >= perm[j + 1] {
+    j -= 1
+  }
+  if j < 0 { return true }
+
+  var l = perm.count - 1
+  while perm[j] >= perm[l] { l -= 1 }
+  perm.swapAt(l, j)
+
+  l = perm.count - 1
+  var k = j + 1
+  while k < l {
+    perm.swapAt(k, l)
+    k += 1
+    l -= 1
+  }
+
+  return false
+}
+
+func allPermutations(_ alphabet: Int) -> [Permutation] {
+  var perm = identityPermutation(alphabet)
+  var perms: [Permutation] = []
+  repeat {
+    perms.append(perm)
+  } while !nextPermutation(&perm)
+  return perms
+}
+
+extension Word {
+  func permuted(_ perm: Permutation) -> Word {
+    return map { Symbol(perm[Int($0)]) }
+  }
+}
+
+extension Rule {
+  func permuted(_ perm: Permutation) -> Rule {
+    return Rule(lhs: lhs.permuted(perm), rhs: rhs.permuted(perm))
+  }
+}
+
+extension Presentation {
+  func permuted(_ perm: Permutation) -> Presentation {
+    return Presentation(alphabet: alphabet,
+                        rules: rules.map { $0.permuted(perm) })
+  }
+}
+
+enum CompareResult {
+  case lessThan
+  case equal
+  case greaterThan
+}
+
+enum Order: Hashable {
+  case shortlex
+  case permutation(Permutation)
+  case wreath([Int], Permutation)
+
+  var simplified: Order {
+    switch self {
+    case .shortlex:
+      return self
+    case .permutation(let perm):
+      // shortlex with identity permutation avoids some indirection
+      if perm == identityPermutation(perm.count) {
+        return .shortlex
+      }
+      return self
+    case .wreath(_, _):
+      return self
+    }
+  }
+
+  func removeGenerator(_ a: Symbol) -> Order {
+    func updatePermutation(_ perm: Permutation, removing i: Int) -> Permutation {
+      return Permutation(perm[0 ..< i] + perm[(i + 1)...]).map {
+        return $0 > perm[i] ? $0 - 1 : $0
+      }
+    }
+
+    switch self {
+    case .shortlex:
+      return self
+
+    case .permutation(let perm):
+      return .permutation(updatePermutation(perm, removing: Int(a)))
+
+    case .wreath(let degrees, let perm):
+      var newDegrees = Array(degrees[0 ..< Int(a)] + degrees[(Int(a) + 1)...])
+      let oldDegree = degrees[Int(a)]
+      if newDegrees.firstIndex(of: oldDegree) == nil {
+        newDegrees = newDegrees.map { $0 > oldDegree ? $0 - 1 : $0 }
+      }
+      let newPerm = updatePermutation(perm, removing: Int(a))
+      if newDegrees.max()! == 0 { return .permutation(newPerm) }
+      return .wreath(newDegrees, newPerm)
+    }
+  }
+}
+
+func shortlex(_ lhs: Word, _ lhsFrom: Int, _ lhsTo: Int,
+              _ rhs: Word, _ rhsFrom: Int, _ rhsTo: Int,
+              perm: Permutation) -> CompareResult {
+  let lhsCount = (lhsTo - lhsFrom)
+  let rhsCount = (rhsTo - rhsFrom)
+  if lhsCount != rhsCount {
+    return lhsCount < rhsCount ? .lessThan : .greaterThan
+  }
+
+  for i in 0 ..< lhsCount {
+    let x = lhs[lhsFrom + i]
+    let y = rhs[rhsFrom + i]
+    if x != y {
+      return perm[Int(x)] < perm[Int(y)] ? .lessThan : .greaterThan
+    }
+  }
+
+  return .equal
+}
+
+// The "wreath product" or "recursive path" order:
+//
+// Sims, C. C. (1994). Computation with Finitely Presented Groups.
+// Cambridge: Cambridge University Press.
+//
+func wreath(_ lhs: Word, _ lhsFrom: Int, _ lhsTo: Int,
+            _ rhs: Word, _ rhsFrom: Int, _ rhsTo: Int,
+            degrees: [Int], perm: Permutation) -> CompareResult {
+  var i = lhsFrom
+  var j = rhsFrom
+
+  while true {
+    if i == lhsTo {
+      if j == rhsTo { return .equal }
+      return .lessThan
+    } else if j == rhsTo {
+      return .greaterThan
+    }
+
+    if lhs[i] != rhs[j] { break }
+    i += 1
+    j += 1
+  }
+
+  func maxDegree(_ word: Word, _ from: Int, _ to: Int)
+      -> (degree: Int, count: Int, symbol: Symbol?) {
+    var degree = -1, count = 0
+    var symbol: Symbol? = nil
+
+    for s in word[from ..< to] {
+      if degrees[Int(s)] > degree {
+        degree = degrees[Int(s)]
+        count = 1
+        symbol = s
+      } else if degrees[Int(s)] == degree {
+        count += 1
+        if symbol != s { symbol = nil }
+      }
+    }
+
+    return (degree, count, symbol)
+  }
+
+  let (lhsMaxDegree, lhsCount, lhsHeadSymbol) = maxDegree(lhs, i, lhsTo)
+  let (rhsMaxDegree, rhsCount, rhsHeadSymbol) = maxDegree(rhs, j, rhsTo)
+  if lhsMaxDegree < rhsMaxDegree {
+    return .lessThan
+  } else if lhsMaxDegree > rhsMaxDegree {
+    return .greaterThan
+  } else if lhsCount < rhsCount {
+    return .lessThan
+  } else if lhsCount > rhsCount {
+    return .greaterThan
+  }
+
+  if lhsHeadSymbol != nil && rhsHeadSymbol != nil {
+    if lhsHeadSymbol != rhsHeadSymbol {
+      return perm[Int(lhsHeadSymbol!)] < perm[Int(rhsHeadSymbol!)]
+          ? .lessThan : .greaterThan
+    }
+  } else {
+    if lhsMaxDegree == 0 {
+      return shortlex(lhs, i, lhsTo, rhs, j, rhsTo, perm: perm)
+    } else {
+      let lhsHeadWord = lhs[i ..< lhsTo].filter { degrees[Int($0)] == lhsMaxDegree }
+      let rhsHeadWord = rhs[j ..< rhsTo].filter { degrees[Int($0)] == rhsMaxDegree }
+
+      let result = shortlex(lhsHeadWord, 0, lhsHeadWord.count,
+                            rhsHeadWord, 0, rhsHeadWord.count,
+                            perm: perm)
+      if result != .equal { return result }
+    }
+  }
+
+  if lhsMaxDegree == 0 { return .equal }
+
+  var ii = i, jj = j
+  while i < lhsTo {
+    while i < lhsTo && degrees[Int(lhs[i])] != lhsMaxDegree { i += 1 }
+    while j < rhsTo && degrees[Int(rhs[j])] != rhsMaxDegree { j += 1 }
+
+    let result = wreath(lhs, ii, i, rhs, jj, j, degrees: degrees, perm: perm)
+    if result != .equal { return result }
+
+    i += 1; ii = i
+    j += 1; jj = j
+  }
+
+  precondition(j == rhsTo)
+  return .equal
+}
+
+func compare(_ lhs: Word, _ rhs: Word, order: Order) -> CompareResult {
+  switch order {
+  case .shortlex:
+    if lhs.count != rhs.count {
+      return lhs.count < rhs.count ? .lessThan : .greaterThan
+    }
+
+    for i in lhs.indices {
+      let x = lhs[i]
+      let y = rhs[i]
+      if x != y {
+        return x < y ? .lessThan : .greaterThan
+      }
+    }
+
+    return .equal
+
+  case .permutation(let perm):
+    return shortlex(lhs, 0, lhs.count, rhs, 0, rhs.count, perm: perm)
+
+  case .wreath(let degrees, let perm):
+    return wreath(lhs, 0, lhs.count, rhs, 0, rhs.count,
+                  degrees: degrees, perm: perm)
+  }
+}
+
+func compare(_ lhs: Rule, _ rhs: Rule, order: Order) -> CompareResult {
+  let result = compare(lhs.lhs, rhs.lhs, order: order)
+  if result != .equal {
+    return result
+  }
+
+  return compare(lhs.rhs, rhs.rhs, order: order)
+}
+
+extension Rule {
+  func oriented(order: Order) -> Rule? {
+    switch compare(lhs, rhs, order: order) {
+    case .equal:
+      return nil
+    case .lessThan:
+      return Rule(lhs: rhs, rhs: lhs)
+    case .greaterThan:
+      return self
+    }
+  }
+}
+
+extension Presentation {
+  func sorted(order: Order) -> Presentation {
+    let sortedRules =
+      rules.map { $0.oriented(order: order)! }
+           .sorted { compare($0, $1, order: order) == .lessThan }
+    return Presentation(alphabet: alphabet, rules: sortedRules)
+  }
+}
diff --git a/benchmark/multi-source/Monoids/README.md b/benchmark/multi-source/Monoids/README.md
new file mode 100644
index 0000000000000..d33f7eb41e242
--- /dev/null
+++ b/benchmark/multi-source/Monoids/README.md
@@ -0,0 +1,26 @@
+# Monoids Benchmark
+
+This benchmark solves the "word problem" in a bunch of monoids simultaneously, using Swift concurrency (or really, just `Task`). It exercises the standard library data structures heavily. You can also run "sh compile.sh" inside the source directory to build a standalone binary separately from the benchmark harness. The standalone binary prints results to standard output.
+
+More specifically, this program enumerates two-generator two-relation monoid presentations up to length 10, and then applies the Knuth-Bendix algorithm to each one:
+
+    <a,b|u=v,w=x>  where |u| + |v| + |w| + |x| <= 10
+
+This takes a few seconds to finish and solves all but three instances. The three it cannot solve are:
+
+    <a,b|aaa=a,abba=bb>
+    <a,b|bab=aaa,bbbb=1>
+    <a,b|aaaa=1,abbba=b>
+
+In addition to Knuth-Bendix completion, there are some other interesting algorithms here as well:
+- Shortlex order with arbitrary permutation of alphabet
+- Wreath product order (also known as recursive path order) with arbitrary degree mapping
+- Enumerating all words, permutations, monoid presentations
+- Inverse of a permutation
+- Computing number of irreducible words in complete presentation (= cardinality of presented monoid) with finite state automata
+
+The Knuth-Bendix implementation is pretty fast. It uses a trie to speed up reduction and finding overlaps.
+
+The main "entry point" is `func run()` in Monoids.swift.
+
+A formal write-up is here: https://factorcode.org/slava/aaaaabbabb.pdf
diff --git a/benchmark/multi-source/Monoids/RewritingSystem.swift b/benchmark/multi-source/Monoids/RewritingSystem.swift
new file mode 100644
index 0000000000000..1d78c9163960d
--- /dev/null
+++ b/benchmark/multi-source/Monoids/RewritingSystem.swift
@@ -0,0 +1,292 @@
+/// This file implements Knuth-Bendix completion and the normal form algorithm.
+
+enum RewritingError: Error {
+  case tooManyRounds
+  case tooManyRules
+  case tooManyNodes
+  case ruleTooLong
+  case tooManySteps
+  case reducedWordTooLong
+}
+
+let debug = false
+
+func log(_ str: @autoclosure () -> String) {
+    if debug {
+        print(str())
+    }
+}
+
+struct RewritingSystem {
+  var state: State = .initial
+
+  enum State {
+    case initial
+    case complete
+    case failed
+  }
+
+  var alphabet: Int
+  var rules: [Rule] = []
+  var trie: Trie
+
+  // Limits for completion
+  struct Limits: Hashable {
+    var maxRounds = 100
+    var maxRules = 200
+    var maxLength = 100
+    var maxReductionLength = 100
+    var maxReductionSteps = 1 << 24
+  }
+
+  var limits = Limits()
+
+  var checkedRulesUpTo = 0  // Completion progress
+  var reducedRules: [UInt32] = []  // Bitmap of reduced rules
+
+  typealias CriticalPair = (i: Int, from: Int, j: Int)
+  var criticalPairs: [CriticalPair] = []  // Temporary array for completion
+
+  var stats = Stats()
+
+  struct Stats {
+    var numRounds = 0
+    var numRulesRemaining = 0  // Number of rules that were not reduced away
+    var numReductionSteps = 0
+  }
+
+  init(alphabet: Int) {
+    self.alphabet = alphabet
+    self.trie = Trie(alphabet: self.alphabet)
+
+    criticalPairs.reserveCapacity(128)
+  }
+
+  mutating func addRules(_ rules: [Rule], order: Order)
+      throws(RewritingError) {
+    for var rule in rules {
+      _ = try addRule(&rule, order: order)
+    }
+  }
+
+  func reduceOne(_ word: Word, excluding: Int? = nil) -> (Int, Int)? {
+    var from = 0
+
+    while from < word.count {
+      if let n = trie.lookup(word, from) {
+        if n != excluding { return (from, n) }
+      }
+
+      from += 1
+    }
+
+    return nil
+  }
+
+  func reduce(_ word: inout Word, stats: inout Stats) throws(RewritingError) {
+    var count = 0
+
+    repeat {
+      guard let (from, n) = reduceOne(word) else { return }
+
+      let index = word.startIndex + from
+      word.replaceSubrange(index ..< index + rules[n].lhs.count,
+                           with: rules[n].rhs)
+      stats.numReductionSteps += (from + rules[n].lhs.count)
+      if stats.numReductionSteps > limits.maxReductionSteps { throw .tooManySteps }
+
+      if count > limits.maxReductionLength { throw .tooManySteps }
+
+      // FIXME: Load bearing
+      if word.count > limits.maxLength { throw .reducedWordTooLong }
+
+      count += 1
+    } while true
+  }
+
+  mutating func addOrientedRule(_ rule: Rule) throws(RewritingError) {
+    let longestSide = max(rule.lhs.count, rule.rhs.count)
+    if longestSide > limits.maxLength { throw .ruleTooLong }
+
+    if stats.numRulesRemaining == limits.maxRules { throw .tooManyRules }
+
+    log("Adding rule \(rules.count) = \(rule)")
+    try trie.insert(rule.lhs, rules.count)
+
+    rules.append(rule)
+    stats.numRulesRemaining += 1
+  }
+
+  mutating func addRule(_ rule: inout Rule, order: Order)
+      throws(RewritingError) -> Bool {
+    try reduce(&rule.lhs, stats: &stats)
+    try reduce(&rule.rhs, stats: &stats)
+
+    switch compare(rule.lhs, rule.rhs, order: order) {
+    case .equal:
+      return false
+
+    case .lessThan:
+      swap(&rule.lhs, &rule.rhs)
+      fallthrough
+
+    case .greaterThan:
+      try addOrientedRule(rule)
+      return true
+    }
+  }
+
+  mutating func resolveOverlap(i: Int, from: Int, j: Int, order: Order)
+      throws(RewritingError) -> Bool {
+    let lhs = rules[i]
+    let rhs = rules[j]
+
+    log("Critical pair: \(i) vs \(j) at \(from)")
+    log("\(printWord(rules[i].lhs))")
+    log("\(String(repeating: " ", count: from))\(printWord(rules[j].lhs))")
+
+    var rule = Rule(lhs: [], rhs: [])
+
+    let end = lhs.lhs.count
+    if from + rhs.lhs.count < end {
+      rule.lhs = lhs.rhs
+
+      rule.rhs.reserveCapacity(lhs.lhs.count - rhs.lhs.count + rhs.rhs.count)
+
+      rule.rhs.append(contentsOf: lhs.lhs[0 ..< from])
+      rule.rhs.append(contentsOf: rhs.rhs)
+      rule.rhs.append(contentsOf: lhs.lhs[(from + rhs.lhs.count)...])
+    } else {
+      rule.lhs.reserveCapacity(lhs.rhs.count + rhs.lhs.count - lhs.lhs.count + from)
+      rule.lhs.append(contentsOf: lhs.rhs)
+      rule.lhs.append(contentsOf: rhs.lhs[(lhs.lhs.count - from)...])
+
+      rule.rhs.reserveCapacity(from + rhs.rhs.count)
+      rule.rhs.append(contentsOf: lhs.lhs[..<from])
+      rule.rhs.append(contentsOf: rhs.rhs)
+    }
+
+    return try addRule(&rule, order: order)
+  }
+
+  mutating func processRule(_ i: Int) {
+    if isReduced(i) { return }
+
+    let lhs = rules[i]
+    var from = 0
+    while from < lhs.lhs.count {
+      trie.visitOverlaps(lhs.lhs, from) { j in
+        precondition(!isReduced(j))
+
+        if i < checkedRulesUpTo && j < checkedRulesUpTo { return }
+
+        if from == 0 {
+          if i == j { return }
+          if rules[j].lhs.count > lhs.lhs.count { return }
+        }
+
+        criticalPairs.append((i: i, from: from, j: j))
+      }
+
+      from += 1
+    }
+  }
+
+  mutating func completeOne(order: Order) throws(RewritingError) -> Bool {
+    precondition(state == .initial)
+
+    precondition(criticalPairs.isEmpty)
+
+    for i in rules.indices {
+      processRule(i)
+    }
+
+    checkedRulesUpTo = rules.count
+    stats.numRounds += 1
+
+    reduceLeft()
+
+    var confluent = true
+
+    do {
+      log("Resolving critical pairs...")
+      for (i, from, j) in criticalPairs {
+        if try resolveOverlap(i: i, from: from, j: j, order: order) {
+          confluent = false
+        }
+      }
+      criticalPairs.removeAll(keepingCapacity: true)
+      log("All critical pairs resolved")
+
+      try reduceRight()
+    } catch let e {
+      state = .failed
+      throw e
+    }
+
+    if confluent {
+      state = .complete
+      return true
+    }
+
+    if stats.numRounds > limits.maxRounds {
+      state = .failed
+      throw .tooManyRounds
+    }
+
+    return false
+  }
+
+  mutating func complete(order: Order) throws(RewritingError) {
+    while try !completeOne(order: order) {}
+  }
+
+  func isReduced(_ rule: Int) -> Bool {
+    let i = (rule >> 5)
+    let j = (rule & 31)
+    if i >= reducedRules.count { return false }
+    return (reducedRules[i] & (1 << j)) != 0
+  }
+
+  mutating func setReduced(_ rule: Int) {
+    let i = (rule >> 5)
+    let j = (rule & 31)
+    while i >= reducedRules.count { reducedRules.append(0) }
+    reducedRules[i] |= (1 << j)
+  }
+
+  mutating func reduceLeft() {
+    if rules.isEmpty { return }
+    log("Reducing left-hand sides...")
+    for (n, rule) in rules.enumerated() {
+      if !isReduced(n) && reduceOne(rule.lhs, excluding: n) != nil {
+        log("Reduced \(n) = \(rule)")
+        setReduced(n)
+        trie.remove(rule.lhs, n)
+        stats.numRulesRemaining -= 1
+        continue
+      }
+    }
+
+    precondition(stats.numRulesRemaining > 0)
+  }
+
+  mutating func reduceRight() throws(RewritingError) {
+    for n in rules.indices {
+      if !isReduced(n) {
+        try reduce(&rules[n].rhs, stats: &stats)
+      }
+    }
+  }
+
+  /// Returns a complete presentation once the rewriting system is complete.
+  var presentation: Presentation {
+    var result: [Rule] = []
+    for (n, rule) in rules.enumerated() {
+      if !isReduced(n) {
+        result.append(rule)
+      }
+    }
+    return Presentation(alphabet: alphabet, rules: result)
+  }
+}
diff --git a/benchmark/multi-source/Monoids/Solver.swift b/benchmark/multi-source/Monoids/Solver.swift
new file mode 100644
index 0000000000000..46b54534be866
--- /dev/null
+++ b/benchmark/multi-source/Monoids/Solver.swift
@@ -0,0 +1,291 @@
+/// This file implements the driver loop which attempts Knuth-Bendix completion
+/// with various strategies on all instances in parallel.
+
+let numTasks = 32
+
+struct Dispatcher {
+  let subset: [Int]
+  let strategies: [Strategy]
+  var currentStrategy = 0
+  var currentInstance = 0
+
+  mutating func next() -> (instance: Int, strategy: Int)? {
+    if subset.isEmpty || currentStrategy == strategies.count { return nil }
+
+    defer {
+      currentInstance += 1
+      if currentInstance == subset.count {
+        currentInstance = 0
+        currentStrategy += 1
+      }
+    }
+
+    return (instance: subset[currentInstance],
+            strategy: currentStrategy)
+  }
+}
+
+struct Solver {
+  let alphabet: Int
+  let instances: [Presentation]
+
+  // This is a list of indices of all remaining unsolved instances.
+  var subset: [Int]
+
+  // Histogram of finite monoid cardinality.
+  var finite: [Int: Int] = [:]
+
+  var factors: [Order: [Int: [Word]]] = [:]
+  var maxFactors: [Int] = []
+
+  var output: Bool
+
+  init(alphabet: Int, instances: [Presentation], output: Bool) {
+    self.alphabet = alphabet
+    self.instances = instances
+    self.subset = Array(instances.indices)
+    self.output = output
+  }
+
+  mutating func solve() async {
+    if output {
+      print("# Remaining \(subset.count)")
+      print("# n:\tpresentation:\tcardinality:\tcomplete:\tstrategy:")
+    }
+
+    // The shortlex order with identity permutation of generators solves
+    // almost everything.
+    await attempt([Strategy()])
+
+    if output {
+      print("# Remaining \(subset.count)")
+      print("# Attempting more reduction orders")
+    }
+
+    var orderMix: [Int: [Order]] = [:]
+    for i in [0, 1] {
+      orderMix[alphabet + i] = getExhaustiveOrderMix(alphabet, i)
+    }
+
+    do {
+      var strategies: [Strategy] = []
+
+      let strategy = Strategy()
+      let orders = orderMix[alphabet]!
+
+      // We already did the first one.
+      for order in orders[1...] {
+        strategies.append(strategy.withOrder(order))
+      }
+
+      await attempt(strategies)
+    }
+
+    if output {
+      print("# Remaining \(subset.count)")
+      print("# Attempting to add a generator")
+    }
+
+    do {
+      collectFactors(orderMix[alphabet]!)
+
+      var strategies: [Strategy] = []
+
+      for factorLength in 2 ..< maxFactors.count {
+        for frequency in [0, 1] {
+          let strategy = Strategy(factorLength: factorLength,
+                                  frequency: frequency)
+          for order in orderMix[alphabet + 1]! {
+            strategies.append(strategy.withOrder(order))
+          }
+        }
+      }
+
+      await attempt(strategies)
+    }
+
+    if output {
+      print("# Remaining \(subset.count)")
+
+      for n in subset {
+        let instance = instances[n]
+        print("\(n + 1)\t\(instance)\thard")
+      }
+
+      print("# Finite monoids: ", terminator: "")
+      print(finite.sorted { $0.0 < $1.0 }
+                  .map { "\($0): \($1)" }
+                  .joined(separator: ", "))
+    }
+  }
+
+  mutating func collectFactors(_ orders: [Order]) {
+    for order in orders {
+      for n in subset {
+        factors[order, default: [:]][n] =
+            collectFactors(n, instances[n], order: order.simplified)
+      }
+    }
+  }
+
+  mutating func collectFactors(_ n: Int, _ p: Presentation, order: Order) -> [Word] {
+    // FIXME: The 6 is a magic number.
+    let words = p.collectFactors(order: order, upToLength: 6)
+    if !words.isEmpty {
+      let longestFactor = words.map { $0.count }.max()!
+      for i in 2 ... longestFactor {
+        let factorsOfLength = words.filter { $0.count == i }
+        while maxFactors.count <= i {
+          maxFactors.append(0)
+        }
+        maxFactors[i] = max(maxFactors[i], factorsOfLength.count)
+      }
+    }
+    return words
+  }
+
+  func prepare(_ instance: Int, _ strategy: Strategy) -> Strategy? {
+    var strategy = strategy
+
+    var factorsOfLength: [Word] = []
+    if let length = strategy.factorLength {
+      let order = strategy.order.removeGenerator(Symbol(alphabet))
+      factorsOfLength = (factors[order]!)[instance]!
+
+      let factorsOfLength = factorsOfLength.filter { $0.count == length }
+      if strategy.frequency >= factorsOfLength.count { return nil }
+
+      // Add a new generator 'c' and a rule 'c=x' for a magic factor 'x'.
+      let newFactor = factorsOfLength[strategy.frequency]
+      let newGenerator = [Symbol(alphabet)]
+
+      // If 'c' is just going to reduce to 'x' there's no point in
+      // considering it further.
+      if compare(newFactor, newGenerator, order: strategy.order) == .lessThan {
+        return nil
+      }
+
+      strategy.extra = [Rule(lhs: newFactor, rhs: newGenerator)]
+    }
+
+    strategy.order = strategy.order.simplified
+    return strategy
+  }
+
+  mutating func attempt(_ strategies: [Strategy]) async {
+    if subset.isEmpty { return }
+
+    await withTaskGroup(of: (Int, Int, Solution?).self) { group in
+      var dispatcher = Dispatcher(subset: subset, strategies: strategies)
+      var solved: [Int: (Int, Solution)] = [:]
+      var pending: [Int: Int] = [:]
+
+      func startTask() {
+        while true {
+          guard let (instance, strategyIndex) = dispatcher.next() else {
+            return
+          }
+
+          if solved[instance] != nil {
+            continue
+          }
+
+          guard let strategy = prepare(instance, strategies[strategyIndex]) else {
+            continue
+          }
+
+          pending[strategyIndex, default: 0] += 1
+
+          let p = instances[instance]
+
+          group.addTask { () -> (Int, Int, Solution?) in
+            if let solution = try? p.complete(strategy) {
+              return (instance, strategyIndex, solution)
+            }
+            return (instance, strategyIndex, nil)
+          }
+
+          return
+        }
+      }
+
+      func completeTask(_ instance: Int, _ strategyIndex: Int, _ solution: Solution?) {
+        pending[strategyIndex, default: 0] -= 1
+        precondition(pending[strategyIndex]! >= 0)
+
+        if let solution {
+          // The lowest-numbered strategy is the 'official' solution for the instance.
+          var betterStrategy = true
+          if let (oldStrategyIndex, _) = solved[instance] {
+            precondition(oldStrategyIndex != strategyIndex)
+            if oldStrategyIndex < strategyIndex {
+              betterStrategy = false
+            }
+          }
+
+          if betterStrategy {
+            solved[instance] = (strategyIndex, solution)
+          }
+        }
+
+        while retireStrategy() {}
+      }
+
+      func retireStrategy() -> Bool {
+        // Check if nothing remains.
+        guard let minPending = pending.keys.min() else { return false }
+
+        // Check if we're going to dispatch more instances with this strategy.
+        precondition(minPending <= dispatcher.currentStrategy)
+        if minPending == dispatcher.currentStrategy { return false }
+
+        // Check if we're still waiting for instances to finish with this
+        // strategy.
+        if pending[minPending]! > 0 { return false }
+
+        // Otherwise, retire this strategy.
+        pending[minPending] = nil
+
+        // Print out all instances solved by this strategy and remove them
+        // from the list.
+        subset = subset.filter { n in
+          guard let (strategyIndex, solution) = solved[n] else { return true }
+          guard strategyIndex == minPending else { return true }
+
+          // Print the instance and solution.
+          var str = "\(n + 1)\t\(instances[n])\t"
+
+          if let cardinality = solution.cardinality {
+            str += "finite:\(cardinality)"
+            finite[cardinality, default: 0] += 1
+          } else {
+            str += "infinite"
+          }
+          str += "\tfcrs:\(solution.presentation)"
+
+          // Print the extra generators that were added, if any.
+          if !solution.extra.isEmpty {
+            str += "\t\(printRules(solution.extra))"
+          }
+
+          if output {
+            print(str)
+          }
+
+          return false
+        }
+
+        return true
+      }
+
+      for _ in 0 ..< numTasks {
+        startTask()
+      }
+
+      for await (instance, strategyIndex, solution) in group {
+        startTask()
+        completeTask(instance, strategyIndex, solution)
+      }
+    }
+  }
+}
diff --git a/benchmark/multi-source/Monoids/Standalone.swift b/benchmark/multi-source/Monoids/Standalone.swift
new file mode 100644
index 0000000000000..3cfcc2e792903
--- /dev/null
+++ b/benchmark/multi-source/Monoids/Standalone.swift
@@ -0,0 +1,13 @@
+// Only generate main entry point if we're not being built as part of the
+// benchmark harness. In this case you get a binary that runs the same
+// workload, except it also prints results to standard output.
+
+#if !canImport(TestsUtils)
+
+@main struct Main {
+  static func main() async {
+    await run(output: true)
+  }
+}
+
+#endif
\ No newline at end of file
diff --git a/benchmark/multi-source/Monoids/Strategy.swift b/benchmark/multi-source/Monoids/Strategy.swift
new file mode 100644
index 0000000000000..9318f901c5ab5
--- /dev/null
+++ b/benchmark/multi-source/Monoids/Strategy.swift
@@ -0,0 +1,104 @@
+/// Generate a bunch of reduction orders.
+func getExhaustiveOrderMix(_ alphabet: Int, _ extraAlphabet: Int) -> [Order] {
+  var result: [Order] = []
+
+  let permutations = allPermutations(alphabet + extraAlphabet)
+
+  for perm in permutations {
+    result.append(.permutation(perm))
+  }
+
+  for perm in permutations {
+    let degrees = perm.map { Int($0) }
+    result.append(.wreath(degrees, perm))
+  }
+
+  return result
+}
+
+/// Parameters for completion.
+struct Strategy: Sendable {
+  var extra: [Rule] = []
+  var factorLength: Int? = nil
+  var frequency: Int = 0
+  var order: Order = .shortlex
+
+  func withOrder(_ order: Order) -> Self {
+    var result = self
+    result.order = order
+    return result
+  }
+}
+
+extension Presentation {
+  func collectFactors(order: Order, upToLength: Int) -> [Word] {
+    let strategy = Strategy()
+    var rws = RewritingSystem(alphabet: alphabet)
+
+    do {
+      try rws.addRules(rules, order: strategy.order)
+
+      for _ in [0, 1] {
+        if try rws.completeOne(order: strategy.order) { break }
+      }
+    } catch {}
+
+    return rws.collectFactors(upToLength: upToLength, order: strategy.order)
+  }
+}
+
+extension Word {
+  func collectFactors(_ table: inout [Word: Int], length: Int) {
+    precondition(length >= 2)
+
+    if length > count { return }
+
+    for i in 0 ... count - length {
+      table[Word(self[i ..< i + length]), default: 0] += 1
+    }
+  }
+}
+
+extension RewritingSystem {
+  func collectFactors(upToLength: Int, order: Order) -> [Word] {
+    var table: [Word: Int] = [:]
+    for n in rules.indices {
+      if isReduced(n) { continue }
+      let lhs = rules[n].lhs
+      for length in 2 ... upToLength {
+        lhs.collectFactors(&table, length: length)
+      }
+    }
+
+    return table.sorted {
+      $0.1 > $1.1 || ($0.1 == $1.1 &&
+                      compare($0.0, $1.0, order: order) == .greaterThan)
+    }.map { $0.key }
+  }
+}
+
+struct Solution {
+  let extra: [Rule]
+  let cardinality: Int?
+  let presentation: Presentation
+}
+
+extension RewritingSystem {
+  func formSolution(_ strategy: Strategy) -> Solution {
+    let p = presentation.sorted(order: strategy.order)
+    return Solution(extra: strategy.extra,
+                    cardinality: cardinality,
+                    presentation: p)
+  }
+}
+
+extension Presentation {
+  func complete(_ strategy: Strategy) throws(RewritingError) -> Solution {
+    var rws = RewritingSystem(alphabet: alphabet + strategy.extra.count)
+    try rws.addRules(rules, order: strategy.order)
+    try rws.addRules(strategy.extra, order: strategy.order)
+
+    try rws.complete(order: strategy.order)
+    return rws.formSolution(strategy)
+  }
+}
diff --git a/benchmark/multi-source/Monoids/Trie.swift b/benchmark/multi-source/Monoids/Trie.swift
new file mode 100644
index 0000000000000..f88fefca43c5b
--- /dev/null
+++ b/benchmark/multi-source/Monoids/Trie.swift
@@ -0,0 +1,136 @@
+struct Trie {
+  typealias Node = Int16
+
+  var values: [Node] = []
+  var children: [Node] = []
+  var freeList: [Node] = []
+
+  let emptyNode: [Node]
+  
+  init(alphabet: Int) {
+    self.emptyNode = Array(repeating: -1, count: alphabet)
+    _ = try! createNode()  // The root node
+  }
+
+  mutating func createNode() throws(RewritingError) -> Node {
+    if !freeList.isEmpty {
+      let result = Int(freeList.removeLast())
+      values.replaceSubrange(result ..< result + emptyNode.count, with: emptyNode)
+      children.replaceSubrange(result ..< result + emptyNode.count, with: emptyNode)
+      return Node(result)
+    }
+
+    let result = values.count
+    if result + emptyNode.count >= 32000 {
+      throw RewritingError.tooManyNodes
+    }
+    values.append(contentsOf: emptyNode)
+    children.append(contentsOf: emptyNode)
+    precondition(values.count == children.count)
+    precondition(values.count % emptyNode.count == 0)
+    return Node(result)
+  }
+
+  mutating func reclaimNode(_ node: Node) {
+    freeList.append(node)
+  }
+
+  mutating func insert(_ key: Word, _ value: Int) throws(RewritingError) {
+    var node = 0
+    for i in 0 ..< key.count - 1 {
+      let s = key[i]
+      if children[node + Int(s)] == -1 {
+        children[node + Int(s)] = try createNode()
+      }
+      node = Int(children[node + Int(s)])
+    }
+    values[node + Int(key.last!)] = Node(value)
+  }
+
+  func lookup(_ key: Word, _ i: Int) -> Int? {
+    var node = 0
+    for s in key[i ..< key.count] {
+      let n = Int(values[node + Int(s)])
+      if n != -1 { return n }
+      node = Int(children[node + Int(s)])
+      if node == -1 { return nil }
+    }
+    return nil
+  }
+
+  // Visits all keys that are equal to a prefix of key[i ...], as well as
+  // all keys whose prefix is equal to key[i ...].
+  func visitOverlaps(_ key: Word, _ from: Int, callback: (Int) -> ()) {
+    var node = 0
+    for s in key[from...] {
+      let n = Int(values[node + Int(s)])
+      if n != -1 { callback(n) }
+      node = Int(children[node + Int(s)])
+      if node == -1 { return }
+    }
+
+    if node == 0 { return }
+
+    var stack: [Int] = [node]
+
+    repeat {
+      let node = stack.removeLast()
+
+      for s in (0 ..< emptyNode.count) {
+        let n = Int(values[node + s])
+        if n != -1 { callback(n) }
+        let child = Int(children[node + s])
+        if child != -1 { stack.append(child) }
+      }
+    } while !stack.isEmpty
+  }
+
+  func isEmptyNode(_ node: Int) -> Bool {
+    for i in 0 ..< emptyNode.count {
+      if values[node + i] != -1 ||
+         children[node + i] != -1 {
+        return false
+      }
+    }
+
+    return true
+  }
+
+  mutating func remove(_ key: Word, _ value: Int) {
+    var node = 0
+    var stack: [Int] = []  // path to current node from root
+
+    for i in 0 ..< key.count - 1 {
+      let s = key[i]
+      precondition(children[node + Int(s)] != -1)
+
+      stack.append(node)
+      node = Int(children[node + Int(s)])
+    }
+
+    let j = node + Int(key.last!)
+    precondition(values[j] == value)
+    values[j] = -1
+
+    // Remove any newly-empty nodes, up to the root.
+    repeat {
+      if !isEmptyNode(node) { return }
+
+      reclaimNode(Node(node))
+
+      let parent = stack.removeLast()
+
+      var sawThis = false
+      for i in 0 ..< emptyNode.count {
+        if Int(children[parent + i]) == node {
+          children[parent + i] = -1
+          sawThis = true
+          break
+        }
+      }
+      precondition(sawThis)
+
+      node = parent
+    } while !stack.isEmpty
+  }
+}
diff --git a/benchmark/multi-source/Monoids/compile.sh b/benchmark/multi-source/Monoids/compile.sh
new file mode 100644
index 0000000000000..3e10c2ed2e8cb
--- /dev/null
+++ b/benchmark/multi-source/Monoids/compile.sh
@@ -0,0 +1 @@
+xcrun swiftc -O Automaton.swift Enumeration.swift Monoids.swift Presentation.swift RewritingSystem.swift Solver.swift Standalone.swift Strategy.swift Trie.swift -O -swift-version 6 -g -wmo -parse-as-library -o Monoids $@
diff --git a/benchmark/scripts/build_script_helper.py b/benchmark/scripts/build_script_helper.py
index cfec15145ac1d..82feb524cd630 100755
--- a/benchmark/scripts/build_script_helper.py
+++ b/benchmark/scripts/build_script_helper.py
@@ -25,8 +25,15 @@ def perform_build(args, swiftbuild_path, config, binary_name, opt_flag):
         "-Xswiftc",
         "-align-module-to-page-size",
         "-Xswiftc",
-        opt_flag,
+        opt_flag
     ]
+
+    if config == "debug":
+        swiftbuild_args += [
+            "-Xswiftc",
+            "-DDEBUG"
+        ]
+
     if args.verbose:
         swiftbuild_args.append("--verbose")
     subprocess.call(swiftbuild_args)
diff --git a/benchmark/scripts/test_Benchmark_Driver.py b/benchmark/scripts/test_Benchmark_Driver.py
index 53f0883092ee4..90efd61bb7301 100644
--- a/benchmark/scripts/test_Benchmark_Driver.py
+++ b/benchmark/scripts/test_Benchmark_Driver.py
@@ -112,7 +112,7 @@ def test_optimization_argument(self):
             [
                 "error:",
                 "argument -o/--optimization: invalid choice: 'bogus'",
-                "(choose from 'O', 'Onone', 'Osize')",
+                "(choose from ",
             ],
             err.getvalue(),
         )
diff --git a/benchmark/scripts/test_compare_perf_tests.py b/benchmark/scripts/test_compare_perf_tests.py
index 72eca5e52b603..db64c6695e672 100644
--- a/benchmark/scripts/test_compare_perf_tests.py
+++ b/benchmark/scripts/test_compare_perf_tests.py
@@ -860,7 +860,7 @@ def test_format_argument(self):
             )
         self.assertIn(
             "error: argument --format: invalid choice: 'bogus' "
-            "(choose from 'markdown', 'git', 'html')",
+            "(choose from ",
             err.getvalue(),
         )
 
diff --git a/benchmark/single-source/CountAlgo.swift b/benchmark/single-source/CountAlgo.swift
index 7361c2b5befb3..7f7ea77d33993 100644
--- a/benchmark/single-source/CountAlgo.swift
+++ b/benchmark/single-source/CountAlgo.swift
@@ -26,7 +26,7 @@ public let benchmarks = [
 @inline(never)
 public func run_CountAlgoArray(_ N: Int) {
   for _ in 1...10*N {
-    CheckResults(numbers.count(where: { $0 & 4095 == 0 }) == 25)
+    check(numbers.count(where: { $0 & 4095 == 0 }) == 25)
   }
 }
 
@@ -34,7 +34,7 @@ public func run_CountAlgoArray(_ N: Int) {
 public func run_CountAlgoString(_ N: Int) {
   let vowels = Set("aeiou")
   for _ in 1...N {
-    CheckResults(text.count(where: vowels.contains) == 2014)
+    check(text.count(where: vowels.contains) == 2014)
   }
 }
 
diff --git a/benchmark/single-source/Diffing.swift b/benchmark/single-source/Diffing.swift
index c84cd92f4ef2a..bc5f3936b5f57 100644
--- a/benchmark/single-source/Diffing.swift
+++ b/benchmark/single-source/Diffing.swift
@@ -49,6 +49,16 @@ public let benchmarks = [
     runFunction: { diff($0, from: unabridgedLorem, to: loremIpsum) },
     tags: t,
     setUpFunction: { blackHole((unabridgedLorem, loremIpsum)) }),
+  BenchmarkInfo(
+    name: "Diffing.Large.Similar",
+    runFunction: { diff($0, from: bigUnabridgedLorem, to: bigLoremIpsum) },
+    tags: t + [.skip],
+    setUpFunction: { blackHole((bigUnabridgedLorem, bigLoremIpsum)) }),
+  BenchmarkInfo(
+    name: "Diffing.Large.Disparate",
+    runFunction: { diff($0, from: bigNumbersAndSymbols, to: bigAlphabets) },
+    tags: t + [.skip],
+    setUpFunction: { blackHole((bigNumbersAndSymbols, bigAlphabets)) }),
 ]
 
 let numbersAndSymbols = Array("0123456789`~!@#$%^&*()+=_-\"'?/<,>.\\{}'")
@@ -59,6 +69,10 @@ let typingPangram = Array("The quick brown fox jumps over the lazy dog")
 let loremIpsum = Array("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.")
 let unabridgedLorem = Array("Lorem ipsum, quia dolor sit amet consectetur adipisci[ng] velit, sed quia non-numquam [do] eius modi tempora inci[di]dunt, ut labore et dolore magnam aliqua.")
 let loremReversed = Array(loremIpsum.reversed())
+let bigLoremIpsum = Array(repeatElement(loremIpsum, count: 100).joined())
+let bigUnabridgedLorem = Array(repeatElement(unabridgedLorem, count: 100).joined())
+let bigNumbersAndSymbols = Array(repeatElement(numbersAndSymbols, count: 250).joined())
+let bigAlphabets = Array(repeatElement(alphabets, count: 250).joined())
 
 @inline(never) func diff(_ n: Int, from older: [Character], to newer: [Character]) {
   if #available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *) {
diff --git a/benchmark/single-source/DiffingMyers.swift b/benchmark/single-source/DiffingMyers.swift
index 12f584b75719a..bb7132657e515 100644
--- a/benchmark/single-source/DiffingMyers.swift
+++ b/benchmark/single-source/DiffingMyers.swift
@@ -187,9 +187,9 @@ fileprivate func myers<C,D>(
    * necessary) is significantly less than the worst-case n² memory use of the
    * descent algorithm.
    */
-  func _withContiguousStorage<C : Collection, R>(
-    for values: C,
-    _ body: (UnsafeBufferPointer<C.Element>) throws -> R
+  func _withContiguousStorage<Col : Collection, R>(
+    for values: Col,
+    _ body: (UnsafeBufferPointer<Col.Element>) throws -> R
   ) rethrows -> R {
     if let result = try values.withContiguousStorageIfAvailable(body) { return result }
     let array = ContiguousArray(values)
diff --git a/benchmark/single-source/ObjectiveCBridging.swift b/benchmark/single-source/ObjectiveCBridging.swift
index c0e9d1a083292..fa9b6d3280cba 100644
--- a/benchmark/single-source/ObjectiveCBridging.swift
+++ b/benchmark/single-source/ObjectiveCBridging.swift
@@ -97,6 +97,27 @@ public let benchmarks = [
   BenchmarkInfo(name: "NSArray.bridged.repeatedBufferAccess",
                   runFunction: run_BridgedNSArrayRepeatedBufferAccess, tags: t,
                   setUpFunction: setup_bridgedArrays),
+  BenchmarkInfo(name: "NSDictionary.bridged.enumerate",
+                  runFunction: run_BridgedNSDictionaryEnumerate, tags: t,
+                  setUpFunction: setup_bridgedDictionaries),
+  BenchmarkInfo(name: "NSString.bridged.byteCount.ascii.ascii",
+                  runFunction: run_BridgedNSStringLengthASCII_ASCII, tags: ts,
+                  setUpFunction: setup_bridgedStrings),
+  BenchmarkInfo(name: "NSString.bridged.byteCount.ascii.utf8",
+                  runFunction: run_BridgedNSStringLengthASCII_UTF8, tags: ts,
+                  setUpFunction: setup_bridgedStrings),
+  BenchmarkInfo(name: "NSString.bridged.byteCount.ascii.utf16",
+                  runFunction: run_BridgedNSStringLengthASCII_UTF16, tags: ts,
+                  setUpFunction: setup_bridgedStrings),
+  BenchmarkInfo(name: "NSString.bridged.byteCount.ascii.macroman",
+                  runFunction: run_BridgedNSStringLengthASCII_MacRoman, tags: ts,
+                  setUpFunction: setup_bridgedStrings),
+  BenchmarkInfo(name: "NSString.bridged.byteCount.utf8.utf8",
+                  runFunction: run_BridgedNSStringLengthUTF8_UTF8, tags: ts,
+                  setUpFunction: setup_bridgedStrings),
+  BenchmarkInfo(name: "NSString.bridged.byteCount.utf8.utf16",
+                  runFunction: run_BridgedNSStringLengthUTF8_UTF16, tags: ts,
+                  setUpFunction: setup_bridgedStrings),
 ]
 
 #if _runtime(_ObjC)
@@ -794,9 +815,12 @@ public func run_UnicodeStringFromCodable(_ n: Int) {
 
 #if _runtime(_ObjC)
 var bridgedArray:NSArray! = nil
+var bridgedDictionaryOfNumbersToNumbers:NSDictionary! = nil
 var bridgedArrayMutableCopy:NSMutableArray! = nil
 var nsArray:NSArray! = nil
 var nsArrayMutableCopy:NSMutableArray! = nil
+var bridgedASCIIString:NSString! = nil
+var bridgedUTF8String:NSString! = nil
 #endif
 
 public func setup_bridgedArrays() {
@@ -804,11 +828,29 @@ public func setup_bridgedArrays() {
   var arr = Array(repeating: NSObject(), count: 100) as [AnyObject]
   bridgedArray = arr as NSArray
   bridgedArrayMutableCopy = (bridgedArray.mutableCopy() as! NSMutableArray)
+
   nsArray = NSArray(objects: &arr, count: 100)
   nsArrayMutableCopy = (nsArray.mutableCopy() as! NSMutableArray)
   #endif
 }
 
+public func setup_bridgedDictionaries() {
+  var numDict = Dictionary<Int, Int>()
+  for i in 0 ..< 100 {
+    numDict[i] = i
+  }
+  bridgedDictionaryOfNumbersToNumbers = numDict as NSDictionary
+}
+
+public func setup_bridgedStrings() {
+  #if _runtime(_ObjC)
+  let str = Array(repeating: "The quick brown fox jumps over the lazy dog.", count: 100).joined()
+  bridgedASCIIString = str as NSString
+  let str2 = Array(repeating: "The quick brown fox jumps over the lazy dög.", count: 100).joined()
+  bridgedUTF8String = str2 as NSString
+  #endif
+}
+
 @inline(never)
 public func run_BridgedNSArrayObjectAtIndex(_ n: Int) {
   #if _runtime(_ObjC)
@@ -820,11 +862,28 @@ public func run_BridgedNSArrayObjectAtIndex(_ n: Int) {
   #endif
 }
 
+private func dictionaryApplier(
+  _ keyPtr: UnsafeRawPointer?,
+  _ valuePtr :UnsafeRawPointer?,
+  _ contextPtr: UnsafeMutableRawPointer?
+) -> Void {}
+
+@inline(never)
+public func run_BridgedNSDictionaryEnumerate(_ n: Int) {
+  #if _runtime(_ObjC)
+  let cf = bridgedDictionaryOfNumbersToNumbers as CFDictionary
+  for _ in 0 ..< n * 50 {
+    // Use CF to prevent Swift from providing an override, forcing going through ObjC bridging
+    CFDictionaryApplyFunction(cf, dictionaryApplier, nil)
+  }
+  #endif
+}
+
 @inline(never)
 public func run_BridgedNSArrayBufferAccess(_ n: Int) {
   #if _runtime(_ObjC)
   for _ in 0 ..< n {
-    for i in 0..<1000 {
+    for _ in 0..<1000 {
       let tmp = nsArray as! [NSObject]
       blackHole(tmp)
       blackHole(tmp.withContiguousStorageIfAvailable {
@@ -841,7 +900,7 @@ public func run_BridgedNSArrayRepeatedBufferAccess(_ n: Int) {
   for _ in 0 ..< n {
     let tmp = nsArray as! [NSObject]
     blackHole(tmp)
-    for i in 0..<1000 {
+    for _ in 0..<1000 {
       blackHole(tmp.withContiguousStorageIfAvailable {
         $0[0]
       })
@@ -883,3 +942,40 @@ public func run_RealNSArrayMutableCopyObjectAtIndex(_ n: Int) {
   #endif
 }
 
+@inline(__always)
+fileprivate func run_BridgedNSStringLength(_ asciiBase: Bool, _ enc: UInt, _ n: Int) {
+  let str = asciiBase ? bridgedASCIIString : bridgedUTF8String
+  for _ in 0 ..< n * 100 {
+    blackHole(str!.lengthOfBytes(using: enc))
+  }
+}
+
+@inline(never)
+public func run_BridgedNSStringLengthASCII_ASCII(_ n: Int) {
+  run_BridgedNSStringLength(true, 1 /* NSASCIIStringEncoding */, n)
+}
+
+@inline(never)
+public func run_BridgedNSStringLengthASCII_UTF8(_ n: Int) {
+  run_BridgedNSStringLength(true, 4 /* NSUTF8StringEncoding */, n)
+}
+
+@inline(never)
+public func run_BridgedNSStringLengthASCII_UTF16(_ n: Int) {
+  run_BridgedNSStringLength(true, 10 /* NSUnicodeStringEncoding */, n)
+}
+
+@inline(never)
+public func run_BridgedNSStringLengthASCII_MacRoman(_ n: Int) {
+  run_BridgedNSStringLength(true, 30 /* NSMacOSRomanStringEncoding */, n)
+}
+
+@inline(never)
+public func run_BridgedNSStringLengthUTF8_UTF8(_ n: Int) {
+  run_BridgedNSStringLength(false, 4 /* NSUTF8StringEncoding */, n)
+}
+
+@inline(never)
+public func run_BridgedNSStringLengthUTF8_UTF16(_ n: Int) {
+  run_BridgedNSStringLength(false, 10 /* NSUnicodeStringEncoding */, n)
+}
diff --git a/benchmark/utils/DriverUtils.swift b/benchmark/utils/DriverUtils.swift
index 733c022b60d83..5785a10dc8174 100644
--- a/benchmark/utils/DriverUtils.swift
+++ b/benchmark/utils/DriverUtils.swift
@@ -23,6 +23,12 @@ import LibProc
 
 import TestsUtils
 
+/// Sorry.
+private func ??<T>(_ x: T?, _ y: @autoclosure () async -> T) async -> T {
+  if let x { return x }
+  return await y()
+}
+
 struct MeasurementMetadata {
   // Note: maxRSS and pages subtract the RSS measured
   // after the benchmark driver setup has finished.
@@ -198,10 +204,16 @@ struct TestConfig {
     action = c.action ?? .run
     allowNondeterministicHashing = c.allowNondeterministicHashing ?? false
     jsonOutput = c.jsonOutput ?? false
+
+    var skipTags: Set<BenchmarkCategory>
+    skipTags = c.tags ?? [.unstable, .skip]
+#if DEBUG
+    skipTags.insert(.long)
+#endif
     tests = TestConfig.filterTests(registeredBenchmarks,
                                     tests: c.tests ?? [],
                                     tags: c.tags ?? [],
-                                    skipTags: c.skipTags ?? [.unstable, .skip])
+                                    skipTags: skipTags)
 
     if tests.count > 0 {
       testNameLength = tests.map{$0.info.name.count}.sorted().reversed().first!
@@ -481,13 +493,13 @@ final class TestRunner {
   }
 
   /// Measure the `fn` and return the average sample time per iteration (μs).
-  func measure(_ name: String, fn: (Int) -> Void, numIters: Int) -> Double {
+  func measure(_ name: String, fn: (Int) async -> Void, numIters: Int) async -> Double {
 #if SWIFT_RUNTIME_ENABLE_LEAK_CHECKER
     name.withCString { p in startTrackingObjects(p) }
 #endif
 
     startMeasurement()
-    fn(numIters)
+    await fn(numIters)
     stopMeasurement()
 
 #if SWIFT_RUNTIME_ENABLE_LEAK_CHECKER
@@ -502,7 +514,7 @@ final class TestRunner {
   }
 
   /// Run the benchmark and return the measured results.
-  func run(_ test: BenchmarkInfo) -> BenchResults? {
+  func run(_ test: BenchmarkInfo) async -> BenchResults? {
     // Before we do anything, check that we actually have a function to
     // run. If we don't it is because the benchmark is not supported on
     // the platform and we should skip it.
@@ -528,8 +540,8 @@ final class TestRunner {
     }
 
     // Determine number of iterations for testFn to run for desired time.
-    func iterationsPerSampleTime() -> (numIters: Int, oneIter: Double) {
-      let oneIter = measure(test.name, fn: testFn, numIters: 1)
+    func iterationsPerSampleTime() async -> (numIters: Int, oneIter: Double) {
+      let oneIter = await measure(test.name, fn: testFn, numIters: 1)
       if oneIter > 0 {
         let timePerSample = c.sampleTime * 1_000_000.0 // microseconds (μs)
         return (max(Int(timePerSample / oneIter), 1), oneIter)
@@ -540,8 +552,8 @@ final class TestRunner {
 
     // Determine the scale of measurements. Re-use the calibration result if
     // it is just one measurement.
-    func calibrateMeasurements() -> Int {
-      let (numIters, oneIter) = iterationsPerSampleTime()
+    func calibrateMeasurements() async -> Int {
+      let (numIters, oneIter) = await iterationsPerSampleTime()
       if numIters == 1 { addSample(oneIter) }
       else { resetMeasurements() } // for accurate yielding reports
       return numIters
@@ -549,19 +561,19 @@ final class TestRunner {
 
     let numIters = min( // Cap to prevent overflow on 32-bit systems when scaled
       Int.max / 10_000, // by the inner loop multiplier inside the `testFn`.
-      c.numIters ?? calibrateMeasurements())
+      await c.numIters ?? (await calibrateMeasurements()))
 
-    let numSamples = c.numSamples ??
+    let numSamples = await c.numSamples ??
       // Compute the number of samples to measure for `sample-time`,
       // clamped in (`min-samples`, 200) range, if the `num-iters` are fixed.
-      max(c.minSamples ?? 1, min(200, c.numIters == nil ? 1 :
-        calibrateMeasurements()))
+      (max(await c.minSamples ?? 1, min(200, c.numIters == nil ? 1 :
+        await calibrateMeasurements())))
 
     samples.reserveCapacity(numSamples)
     logVerbose("    Collecting \(numSamples) samples.")
     logVerbose("    Measuring with scale \(numIters).")
     for _ in samples.count..<numSamples {
-      addSample(measure(test.name, fn: testFn, numIters: numIters))
+      addSample(await measure(test.name, fn: testFn, numIters: numIters))
     }
 
     test.tearDownFunction?()
@@ -681,16 +693,16 @@ final class TestRunner {
   }
 
   /// Run each benchmark and emit the results in JSON
-  func runBenchmarks() {
+  func runBenchmarks() async {
     var testCount = 0
     if !c.jsonOutput {
       printTextHeading()
     }
     for (index, info) in c.tests {
       if c.jsonOutput {
-	printJSON(index: index, info: info, results: run(info))
+	printJSON(index: index, info: info, results: await run(info))
       } else {
-	printText(index: index, info: info, results: run(info))
+	printText(index: index, info: info, results: await run(info))
       }
       testCount += 1
     }
@@ -712,7 +724,7 @@ extension Hasher {
   }
 }
 
-public func main() {
+public func main() async {
   let config = TestConfig(registeredBenchmarks)
   switch (config.action) {
   case .listTests:
@@ -742,7 +754,7 @@ public func main() {
         the option '--allow-nondeterministic-hashing to the benchmarking executable.
         """)
     }
-    TestRunner(config).runBenchmarks()
+    await TestRunner(config).runBenchmarks()
     if let x = config.afterRunSleep {
       sleep(x)
     }
diff --git a/benchmark/utils/TestsUtils.swift b/benchmark/utils/TestsUtils.swift
index 07d9e35c3359d..543b05251eebb 100644
--- a/benchmark/utils/TestsUtils.swift
+++ b/benchmark/utils/TestsUtils.swift
@@ -69,6 +69,9 @@ public enum BenchmarkCategory : String {
   // significant optimization.
   case cpubench
 
+  // Benchmarks to skip on -Onone runs.
+  case long
+
   // Explicit skip marker
   case skip
 }
@@ -113,10 +116,10 @@ public struct BenchmarkInfo {
   public var name: String
 
   /// Shadow static variable for runFunction.
-  private var _runFunction: (Int) -> ()
+  private var _runFunction: (Int) async -> ()
 
   /// A function that invokes the specific benchmark routine.
-  public var runFunction: ((Int) -> ())? {
+  public var runFunction: ((Int) async -> ())? {
     if !shouldRun {
       return nil
     }
@@ -171,7 +174,7 @@ public struct BenchmarkInfo {
   /// to be interrupted by a context switch.
   public var legacyFactor: Int?
 
-  public init(name: String, runFunction: @escaping (Int) -> (), tags: [BenchmarkCategory],
+  public init(name: String, runFunction: @escaping (Int) async -> (), tags: [BenchmarkCategory],
               setUpFunction: (() -> ())? = nil,
               tearDownFunction: (() -> ())? = nil,
               unsupportedPlatforms: BenchmarkPlatformSet = [],
diff --git a/benchmark/utils/main.swift b/benchmark/utils/main.swift
index 869a782053138..f19e3ea8951d8 100644
--- a/benchmark/utils/main.swift
+++ b/benchmark/utils/main.swift
@@ -117,6 +117,7 @@ import LuhnAlgoLazy
 import MapReduce
 import Memset
 import MirrorTest
+import Monoids
 import MonteCarloE
 import MonteCarloPi
 import NaiveRangeReplaceableCollectionConformance
@@ -317,6 +318,7 @@ register(LuhnAlgoLazy.benchmarks)
 register(MapReduce.benchmarks)
 register(Memset.benchmarks)
 register(MirrorTest.benchmarks)
+register(Monoids.benchmarks)
 register(MonteCarloE.benchmarks)
 register(MonteCarloPi.benchmarks)
 register(NaiveRangeReplaceableCollectionConformance.benchmarks)
@@ -419,4 +421,4 @@ register(Walsh.benchmarks)
 register(WordCount.benchmarks)
 register(XorLoop.benchmarks)
 
-main()
+await main()
diff --git a/cmake/SwiftVersion.cmake b/cmake/SwiftVersion.cmake
index 95bea344619fa..1408188dcbe40 100644
--- a/cmake/SwiftVersion.cmake
+++ b/cmake/SwiftVersion.cmake
@@ -2,6 +2,6 @@
 # can be reused when a new version of Swift comes out (assuming the user hasn't
 # manually set it as part of their own CMake configuration).
 set(SWIFT_VERSION_MAJOR 6)
-set(SWIFT_VERSION_MINOR 2)
+set(SWIFT_VERSION_MINOR 3)
 set(SWIFT_VERSION "${SWIFT_VERSION_MAJOR}.${SWIFT_VERSION_MINOR}")
 
diff --git a/cmake/caches/Windows-aarch64.cmake b/cmake/caches/Windows-aarch64.cmake
index 1eb8b6e432646..22c36750d3830 100644
--- a/cmake/caches/Windows-aarch64.cmake
+++ b/cmake/caches/Windows-aarch64.cmake
@@ -13,10 +13,6 @@ set(LLVM_ENABLE_RUNTIMES
       compiler-rt
     CACHE STRING "")
 
-# NOTE(compnerd) always enable assertions, the toolchain will not provide enough
-# context to resolve issues otherwise and may silently generate invalid output.
-set(LLVM_ENABLE_ASSERTIONS YES CACHE BOOL "")
-
 set(ENABLE_X86_RELAX_RELOCATIONS YES CACHE BOOL "")
 
 # NOTE(compnerd) we can hardcode the default target triple since the cache files
diff --git a/cmake/caches/Windows-x86_64.cmake b/cmake/caches/Windows-x86_64.cmake
index 0074813978d94..84903f1499740 100644
--- a/cmake/caches/Windows-x86_64.cmake
+++ b/cmake/caches/Windows-x86_64.cmake
@@ -13,10 +13,6 @@ set(LLVM_ENABLE_RUNTIMES
       compiler-rt
     CACHE STRING "")
 
-# NOTE(compnerd) always enable assertions, the toolchain will not provide enough
-# context to resolve issues otherwise and may silently generate invalid output.
-set(LLVM_ENABLE_ASSERTIONS YES CACHE BOOL "")
-
 set(ENABLE_X86_RELAX_RELOCATIONS YES CACHE BOOL "")
 
 # NOTE(compnerd) we can hardcode the default target triple since the cache files
diff --git a/cmake/modules/AddSwift.cmake b/cmake/modules/AddSwift.cmake
index 9dc517f62b6d7..ed28ab1891dba 100644
--- a/cmake/modules/AddSwift.cmake
+++ b/cmake/modules/AddSwift.cmake
@@ -324,6 +324,9 @@ function(_add_host_variant_c_compile_flags target)
     target_compile_definitions(${target} PRIVATE
       $<$<COMPILE_LANGUAGE:C,CXX,OBJC,OBJCXX>:_LARGEFILE_SOURCE _FILE_OFFSET_BITS=64>)
   endif()
+
+  target_compile_definitions(${target} PRIVATE
+    $<$<AND:$<COMPILE_LANGUAGE:C,CXX,OBJC,OBJCXX>,$<BOOL:${SWIFT_ENABLE_SWIFT_IN_SWIFT}>>:SWIFT_ENABLE_SWIFT_IN_SWIFT>)
 endfunction()
 
 function(_add_host_variant_link_flags target)
@@ -547,6 +550,19 @@ function(_add_swift_runtime_link_flags target relpath_to_lib_dir bootstrapping)
         else()
           get_filename_component(swift_bin_dir ${SWIFT_EXEC_FOR_SWIFT_MODULES} DIRECTORY)
           get_filename_component(swift_dir ${swift_bin_dir} DIRECTORY)
+
+          # Detect and handle swiftly-managed hosts.
+          if(swift_bin_dir MATCHES ".*/swiftly/bin")
+            execute_process(COMMAND swiftly use --print-location
+              OUTPUT_VARIABLE swiftly_dir
+              ERROR_VARIABLE err)
+            if(err)
+              message(SEND_ERROR "Failed to find swiftly Swift compiler")
+            endif()
+            string(STRIP "${swiftly_dir}" swiftly_dir)
+            set(swift_dir "${swiftly_dir}/usr")
+          endif()
+
         endif()
         set(host_lib_dir "${swift_dir}/lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
       else()
@@ -608,6 +624,19 @@ function(_add_swift_runtime_link_flags target relpath_to_lib_dir bootstrapping)
         else()
           get_filename_component(swift_bin_dir ${SWIFT_EXEC_FOR_SWIFT_MODULES} DIRECTORY)
           get_filename_component(swift_dir ${swift_bin_dir} DIRECTORY)
+
+          # Detect and handle swiftly-managed hosts.
+          if(swift_bin_dir MATCHES ".*/swiftly/bin")
+            execute_process(COMMAND swiftly use --print-location
+              OUTPUT_VARIABLE swiftly_dir
+              ERROR_VARIABLE err)
+            if(err)
+              message(SEND_ERROR "Failed to find swiftly Swift compiler")
+            endif()
+            string(STRIP "${swiftly_dir}" swiftly_dir)
+            set(swift_dir "${swiftly_dir}/usr")
+          endif()
+
           set(host_lib_dir "${swift_dir}/lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
           target_link_directories(${target} PRIVATE ${host_lib_dir})
 
@@ -965,6 +994,11 @@ function(add_swift_host_tool executable)
     endif()
   endif()
 
+  # Opt-out of OpenBSD BTCFI if instructed where it is enforced by default.
+  if(SWIFT_HOST_VARIANT_SDK STREQUAL "OPENBSD" AND SWIFT_HOST_VARIANT_ARCH STREQUAL "aarch64" AND NOT SWIFT_OPENBSD_BTCFI)
+    target_link_options(${executable} PRIVATE "LINKER:-z,nobtcfi")
+  endif()
+
   if(SWIFT_BUILD_SWIFT_SYNTAX)
     set(extra_relative_rpath "")
     if(NOT "${ASHT_BOOTSTRAPPING}" STREQUAL "")
diff --git a/cmake/modules/DarwinSDKs.cmake b/cmake/modules/DarwinSDKs.cmake
index 20d555b74751c..5d4d1ea59e800 100644
--- a/cmake/modules/DarwinSDKs.cmake
+++ b/cmake/modules/DarwinSDKs.cmake
@@ -12,7 +12,8 @@ is_sdk_requested(OSX swift_build_osx)
 if(swift_build_osx)
   configure_sdk_darwin(
       OSX "OS X" "${SWIFT_DARWIN_DEPLOYMENT_VERSION_OSX}"
-      macosx macosx macos "${SUPPORTED_OSX_ARCHS}")
+      macosx macosx macos macOS "${SUPPORTED_OSX_ARCHS}"
+      "${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX}")
   configure_target_variant(OSX-DA "OS X Debug+Asserts"   OSX DA "Debug+Asserts")
   configure_target_variant(OSX-RA "OS X Release+Asserts" OSX RA "Release+Asserts")
   configure_target_variant(OSX-R  "OS X Release"         OSX R  "Release")
@@ -22,27 +23,29 @@ is_sdk_requested(FREESTANDING swift_build_freestanding)
 if(swift_build_freestanding AND (SWIFT_FREESTANDING_FLAVOR STREQUAL "apple"))
   set(SWIFT_FREESTANDING_SDK "" CACHE STRING
       "Which SDK to use when building the FREESTANDING stdlib")
+  set(SWIFT_FREESTANDING_DEPLOYMENT_VERSION "" CACHE STRING
+      "The deployment version to use when building the FREESTANDING stdlib")
   set(SWIFT_FREESTANDING_TRIPLE_NAME "" CACHE STRING
       "Which triple name (e.g. 'none-macho') to use when building the FREESTANDING stdlib")
   set(SWIFT_FREESTANDING_MODULE_NAME "" CACHE STRING
       "Which .swiftmodule name (e.g. 'freestanding') to use when building the FREESTANDING stdlib")
+  set(SWIFT_FREESTANDING_AVAILABILITY_NAME "" CACHE STRING
+      "Which @availability name (e.g. 'macOS') to use when building the FREESTANDING stdlib")
   set(SWIFT_FREESTANDING_ARCHS "" CACHE STRING
       "Which architectures to build when building the FREESTANDING stdlib")
   configure_sdk_darwin(
-      FREESTANDING "FREESTANDING" ""
+      FREESTANDING "FREESTANDING" "${SWIFT_FREESTANDING_DEPLOYMENT_VERSION}"
       "${SWIFT_FREESTANDING_SDK}"
-      "${SWIFT_FREESTANDING_TRIPLE_NAME}" "${SWIFT_FREESTANDING_MODULE_NAME}" "${SWIFT_FREESTANDING_ARCHS}")
+      "${SWIFT_FREESTANDING_TRIPLE_NAME}" "${SWIFT_FREESTANDING_MODULE_NAME}"
+      "${SWIFT_FREESTANDING_AVAILABILITY_NAME}" "${SWIFT_FREESTANDING_ARCHS}"
+      "${SWIFT_FREESTANDING_DEPLOYMENT_VERSION}")
   set(SWIFT_SDK_FREESTANDING_LIB_SUBDIR "freestanding")
   configure_target_variant(FREESTANDING-DA "FREESTANDING Debug+Asserts"   FREESTANDING DA "Debug+Asserts")
   configure_target_variant(FREESTANDING-RA "FREESTANDING Release+Asserts" FREESTANDING RA "Release+Asserts")
   configure_target_variant(FREESTANDING-R  "FREESTANDING Release"         FREESTANDING R  "Release")
   configure_target_variant(FREESTANDING-S  "FREESTANDING MinSizeRelease"  FREESTANDING S  "MinSizeRelease")
 
-  if(SWIFT_BUILD_SDK_OVERLAY)
-    set(SWIFT_FREESTANDING_TEST_DEPENDENCIES "Darwin")
-  else()
-    set(SWIFT_FREESTANDING_TEST_DEPENDENCIES "")
-  endif()
+  set(SWIFT_FREESTANDING_TEST_DEPENDENCIES "")
 endif()
 
 # Compatible cross-compile SDKS for Darwin OSes: IOS, IOS_SIMULATOR, TVOS,
@@ -53,7 +56,8 @@ is_sdk_requested(IOS swift_build_ios)
 if(swift_build_ios)
   configure_sdk_darwin(
       IOS "iOS" "${SWIFT_DARWIN_DEPLOYMENT_VERSION_IOS}"
-      iphoneos ios ios "${SUPPORTED_IOS_ARCHS}")
+      iphoneos ios ios iOS "${SUPPORTED_IOS_ARCHS}"
+      "${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}")
   configure_target_variant(IOS-DA "iOS Debug+Asserts"   IOS DA "Debug+Asserts")
   configure_target_variant(IOS-RA "iOS Release+Asserts" IOS RA "Release+Asserts")
   configure_target_variant(IOS-R  "iOS Release"         IOS R "Release")
@@ -63,8 +67,9 @@ is_sdk_requested(IOS_SIMULATOR swift_build_ios_simulator)
 if(swift_build_ios_simulator)
   configure_sdk_darwin(
       IOS_SIMULATOR "iOS Simulator" "${SWIFT_DARWIN_DEPLOYMENT_VERSION_IOS}"
-      iphonesimulator ios ios-simulator
-      "${SUPPORTED_IOS_SIMULATOR_ARCHS}")
+      iphonesimulator ios ios-simulator iOS
+      "${SUPPORTED_IOS_SIMULATOR_ARCHS}"
+      "${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}")
   configure_target_variant(
       IOS_SIMULATOR-DA "iOS Debug+Asserts"   IOS_SIMULATOR DA "Debug+Asserts")
   configure_target_variant(
@@ -77,7 +82,8 @@ is_sdk_requested(TVOS swift_build_tvos)
 if(swift_build_tvos)
   configure_sdk_darwin(
       TVOS "tvOS" "${SWIFT_DARWIN_DEPLOYMENT_VERSION_TVOS}"
-      appletvos tvos tvos "${SUPPORTED_TVOS_ARCHS}")
+      appletvos tvos tvos tvOS "${SUPPORTED_TVOS_ARCHS}"
+      "${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}")
   configure_target_variant(TVOS-DA "tvOS Debug+Asserts"   TVOS DA "Debug+Asserts")
   configure_target_variant(TVOS-RA "tvOS Release+Asserts" TVOS RA "Release+Asserts")
   configure_target_variant(TVOS-R  "tvOS Release"         TVOS R "Release")
@@ -87,8 +93,9 @@ is_sdk_requested(TVOS_SIMULATOR swift_build_tvos_simulator)
 if(swift_build_tvos_simulator)
   configure_sdk_darwin(
       TVOS_SIMULATOR "tvOS Simulator" "${SWIFT_DARWIN_DEPLOYMENT_VERSION_TVOS}"
-      appletvsimulator tvos tvos-simulator
-      "${SUPPORTED_TVOS_SIMULATOR_ARCHS}")
+      appletvsimulator tvos tvos-simulator tvOS
+      "${SUPPORTED_TVOS_SIMULATOR_ARCHS}"
+      "${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}")
   configure_target_variant(
     TVOS_SIMULATOR-DA "tvOS Debug+Asserts"   TVOS_SIMULATOR DA "Debug+Asserts")
   configure_target_variant(
@@ -101,7 +108,8 @@ is_sdk_requested(WATCHOS swift_build_watchos)
 if(swift_build_watchos)
   configure_sdk_darwin(
       WATCHOS "watchOS" "${SWIFT_DARWIN_DEPLOYMENT_VERSION_WATCHOS}"
-      watchos watchos watchos "${SUPPORTED_WATCHOS_ARCHS}")
+      watchos watchos watchos watchOS "${SUPPORTED_WATCHOS_ARCHS}"
+      "${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}")
   configure_target_variant(WATCHOS-DA "watchOS Debug+Asserts"   WATCHOS DA "Debug+Asserts")
   configure_target_variant(WATCHOS-RA "watchOS Release+Asserts" WATCHOS RA "Release+Asserts")
   configure_target_variant(WATCHOS-R  "watchOS Release"         WATCHOS R "Release")
@@ -111,8 +119,9 @@ is_sdk_requested(WATCHOS_SIMULATOR swift_build_watchos_simulator)
 if(swift_build_watchos_simulator)
   configure_sdk_darwin(
       WATCHOS_SIMULATOR "watchOS Simulator" "${SWIFT_DARWIN_DEPLOYMENT_VERSION_WATCHOS}"
-      watchsimulator watchos watchos-simulator
-      "${SUPPORTED_WATCHOS_SIMULATOR_ARCHS}")
+      watchsimulator watchos watchos-simulator watchOS
+      "${SUPPORTED_WATCHOS_SIMULATOR_ARCHS}"
+      "${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}")
   configure_target_variant(WATCHOS_SIMULATOR-DA "watchOS Debug+Asserts"   WATCHOS_SIMULATOR DA "Debug+Asserts")
   configure_target_variant(WATCHOS_SIMULATOR-RA "watchOS Release+Asserts" WATCHOS_SIMULATOR RA "Release+Asserts")
   configure_target_variant(WATCHOS_SIMULATOR-R  "watchOS Release"         WATCHOS_SIMULATOR R "Release")
@@ -122,7 +131,8 @@ is_sdk_requested(XROS swift_build_xros)
 if(swift_build_xros)
   configure_sdk_darwin(
       XROS "xrOS" "${SWIFT_DARWIN_DEPLOYMENT_VERSION_XROS}"
-      xros xros xros "${SUPPORTED_XROS_ARCHS}")
+      xros xros xros visionOS "${SUPPORTED_XROS_ARCHS}"
+      "${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}")
   configure_target_variant(XROS-DA "xrOS Debug+Asserts"   XROS DA "Debug+Asserts")
   configure_target_variant(XROS-RA "xrOS Release+Asserts" XROS RA "Release+Asserts")
   configure_target_variant(XROS-R  "xrOS Release"         XROS R "Release")
@@ -132,8 +142,9 @@ is_sdk_requested(XROS_SIMULATOR swift_build_xros_simulator)
 if(swift_build_xros_simulator)
   configure_sdk_darwin(
       XROS_SIMULATOR "xrOS Simulator" "${SWIFT_DARWIN_DEPLOYMENT_VERSION_XROS}"
-      xrsimulator xros xros-simulator
-      "${SUPPORTED_XROS_SIMULATOR_ARCHS}")
+      xrsimulator xros xros-simulator visionOS
+      "${SUPPORTED_XROS_SIMULATOR_ARCHS}"
+      "${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}")
 
   configure_target_variant(
       XROS_SIMULATOR-DA "xrOS Simulator Debug+Asserts"   XROS_SIMULATOR DA "Debug+Asserts")
diff --git a/cmake/modules/SwiftCXXUtils.cmake b/cmake/modules/SwiftCXXUtils.cmake
index bdc289985fc39..ea28fafd3de35 100644
--- a/cmake/modules/SwiftCXXUtils.cmake
+++ b/cmake/modules/SwiftCXXUtils.cmake
@@ -1,6 +1,5 @@
 # Platforms that use libstdc++ as the system-wide default C++ standard library.
 set(SWIFT_LIBSTDCXX_PLATFORMS
     "LINUX"
-    "FREEBSD"
     "CYGWIN"
     "HAIKU")
diff --git a/cmake/modules/SwiftConfigureSDK.cmake b/cmake/modules/SwiftConfigureSDK.cmake
index 53036dafcf192..7bed56fb6ca66 100644
--- a/cmake/modules/SwiftConfigureSDK.cmake
+++ b/cmake/modules/SwiftConfigureSDK.cmake
@@ -32,6 +32,7 @@ function(_report_sdk prefix)
     message(STATUS "  Version: ${SWIFT_SDK_${prefix}_VERSION}")
     message(STATUS "  Build number: ${SWIFT_SDK_${prefix}_BUILD_NUMBER}")
     message(STATUS "  Deployment version: ${SWIFT_SDK_${prefix}_DEPLOYMENT_VERSION}")
+    message(STATUS "  Deployment version for tests: ${SWIFT_SDK_${prefix}_TEST_DEPLOYMENT_VERSION}")
     message(STATUS "  Triple name: ${SWIFT_SDK_${prefix}_TRIPLE_NAME}")
     message(STATUS "  Simulator: ${SWIFT_SDK_${prefix}_IS_SIMULATOR}")
   endif()
@@ -53,7 +54,7 @@ function(_report_sdk prefix)
     endforeach()
   elseif("${prefix}" STREQUAL "ANDROID")
     if(NOT "${SWIFT_ANDROID_NDK_PATH}" STREQUAL "")
-      message(STATUS " NDK: $ENV{SWIFT_ANDROID_NDK_PATH}")
+      message(STATUS " NDK: ${SWIFT_ANDROID_NDK_PATH}")
     endif()
     if(NOT "${SWIFT_ANDROID_NATIVE_SYSROOT}" STREQUAL "")
       message(STATUS " Sysroot: ${SWIFT_ANDROID_NATIVE_SYSROOT}")
@@ -136,7 +137,9 @@ endfunction()
 #     deployment_version # Deployment version
 #     xcrun_name         # SDK name to use with xcrun
 #     triple_name        # The name used in Swift's -triple
+#     availability_name  # The name used in Swift's @availability
 #     architectures      # A list of architectures this SDK supports
+#     test_deployment_version # Deployment versions to be used for tests
 #   )
 #
 # Sadly there are three OS naming conventions.
@@ -165,9 +168,12 @@ endfunction()
 #   SWIFT_SDK_${prefix}_ARCH_${ARCH}_TRIPLE       Triple name
 #   SWIFT_SDK_${prefix}_ARCH_${ARCH}_MODULE       Module triple name for this SDK
 #   SWIFT_SDK_${prefix}_USE_BUILD_ID              Whether to pass --build-id to the linker
+#   SWIFT_SDK_${prefix}_AVAILABILITY_NAME       Name to use in @availability
+#
 macro(configure_sdk_darwin
     prefix name deployment_version xcrun_name
-    triple_name module_name architectures)
+    triple_name module_name availability_name architectures
+    test_deployment_version)
   # Note: this has to be implemented as a macro because it sets global
   # variables.
 
@@ -199,8 +205,14 @@ macro(configure_sdk_darwin
   # Set other variables.
   set(SWIFT_SDK_${prefix}_NAME "${name}")
   set(SWIFT_SDK_${prefix}_DEPLOYMENT_VERSION "${deployment_version}")
+  if(NOT "${test_deployment_version}" STREQUAL "")
+    set(SWIFT_SDK_${prefix}_TEST_DEPLOYMENT_VERSION "${test_deployment_version}")
+  else()
+    set(SWIFT_SDK_${prefix}_TEST_DEPLOYMENT_VERSION "${deployment_version}")
+  endif()
   set(SWIFT_SDK_${prefix}_LIB_SUBDIR "${xcrun_name}")
   set(SWIFT_SDK_${prefix}_TRIPLE_NAME "${triple_name}")
+  set(SWIFT_SDK_${prefix}_AVAILABILITY_NAME "${availability_name}")
   set(SWIFT_SDK_${prefix}_OBJECT_FORMAT "MACHO")
   set(SWIFT_SDK_${prefix}_USE_ISYSROOT TRUE)
   set(SWIFT_SDK_${prefix}_SHARED_LIBRARY_PREFIX "lib")
@@ -417,7 +429,7 @@ macro(configure_sdk_unix name architectures)
           message(FATAL_ERROR "unknown arch for ${prefix}: ${arch}")
         endif()
       elseif("${prefix}" STREQUAL "FREEBSD")
-        if(NOT arch MATCHES "(arm64|x86_64)")
+        if(NOT arch MATCHES "(aarch64|x86_64)")
           message(FATAL_ERROR "unsupported arch for FreeBSD: ${arch}")
         endif()
 
@@ -428,7 +440,8 @@ macro(configure_sdk_unix name architectures)
         string(REGEX REPLACE "[-].*" "" freebsd_system_version ${CMAKE_SYSTEM_VERSION})
         message(STATUS "FreeBSD Version: ${freebsd_system_version}")
 
-        set(SWIFT_SDK_FREEBSD_ARCH_${arch}_TRIPLE "${arch}-unknown-freebsd")
+        set(SWIFT_SDK_FREEBSD_ARCH_${arch}_TRIPLE "${arch}-unknown-freebsd${freebsd_system_version}")
+        set(SWIFT_SDK_FREEBSD_ARCH_${arch}_MODULE "${arch}-unknown-freebsd")
       elseif("${prefix}" STREQUAL "OPENBSD")
         if(NOT arch STREQUAL "x86_64" AND NOT arch STREQUAL "aarch64")
           message(FATAL_ERROR "unsupported arch for OpenBSD: ${arch}")
@@ -439,6 +452,8 @@ macro(configure_sdk_unix name architectures)
 
         set(SWIFT_SDK_OPENBSD_ARCH_${arch}_TRIPLE "${arch}-unknown-openbsd${openbsd_system_version}")
 
+        add_link_options("LINKER:-z,origin")
+
         if(CMAKE_SYSROOT)
           set(SWIFT_SDK_OPENBSD_ARCH_${arch}_PATH "${CMAKE_SYSROOT}${SWIFT_SDK_OPENBSD_ARCH_${arch}_PATH}" CACHE INTERNAL "sysroot path" FORCE)
         endif()
@@ -460,7 +475,7 @@ macro(configure_sdk_unix name architectures)
         if(SWIFT_ENABLE_WASI_THREADS)
           set(SWIFT_SDK_WASI_ARCH_wasm32_TRIPLE "wasm32-unknown-wasip1-threads")
         else()
-          set(SWIFT_SDK_WASI_ARCH_wasm32_TRIPLE "wasm32-unknown-wasi")
+          set(SWIFT_SDK_WASI_ARCH_wasm32_TRIPLE "wasm32-unknown-wasip1")
         endif()
       elseif("${prefix}" STREQUAL "EMSCRIPTEN")
         set(SWIFT_SDK_EMSCRIPTEN_ARCH_${arch}_TRIPLE "${arch}-unknown-emscripten")
diff --git a/cmake/modules/SwiftSetIfArchBitness.cmake b/cmake/modules/SwiftSetIfArchBitness.cmake
index cbf16c7e754d3..8268b33f4192d 100644
--- a/cmake/modules/SwiftSetIfArchBitness.cmake
+++ b/cmake/modules/SwiftSetIfArchBitness.cmake
@@ -27,15 +27,15 @@ function(set_if_arch_bitness var_name)
      "${SIA_ARCH}" STREQUAL "powerpc")
     set("${var_name}" "${SIA_CASE_32_BIT}" PARENT_SCOPE)
   elseif("${SIA_ARCH}" STREQUAL "x86_64" OR
-         "${SIA_ARCH}" STREQUAL "amd64" OR
-         "${SIA_ARCH}" STREQUAL "arm64" OR
-         "${SIA_ARCH}" STREQUAL "arm64e" OR
-         "${SIA_ARCH}" STREQUAL "aarch64" OR
-         "${SIA_ARCH}" STREQUAL "powerpc64" OR
-         "${SIA_ARCH}" STREQUAL "powerpc64le" OR
-         "${SIA_ARCH}" STREQUAL "s390x" OR
-         "${SIA_ARCH}" STREQUAL "riscv64" OR
-         "${SIA_ARCH}" STREQUAL "wasm64")
+     "${SIA_ARCH}" STREQUAL "amd64" OR
+     "${SIA_ARCH}" STREQUAL "arm64" OR
+     "${SIA_ARCH}" STREQUAL "arm64e" OR
+     "${SIA_ARCH}" STREQUAL "aarch64" OR
+     "${SIA_ARCH}" STREQUAL "powerpc64" OR
+     "${SIA_ARCH}" STREQUAL "powerpc64le" OR
+     "${SIA_ARCH}" STREQUAL "s390x" OR
+     "${SIA_ARCH}" STREQUAL "riscv64" OR
+     "${SIA_ARCH}" STREQUAL "wasm64")
     set("${var_name}" "${SIA_CASE_64_BIT}" PARENT_SCOPE)
   else()
     message(FATAL_ERROR "Unknown architecture: ${SIA_ARCH}")
diff --git a/cmake/modules/SwiftUtils.cmake b/cmake/modules/SwiftUtils.cmake
index daeb693fb7b0d..34f8017d6ccf5 100644
--- a/cmake/modules/SwiftUtils.cmake
+++ b/cmake/modules/SwiftUtils.cmake
@@ -115,6 +115,19 @@ function(get_bootstrapping_swift_lib_dir bs_lib_dir bootstrapping)
       # FIXME: This assumes the ABI hasn't changed since the builder.
       get_filename_component(swift_bin_dir ${CMAKE_Swift_COMPILER} DIRECTORY)
       get_filename_component(swift_dir ${swift_bin_dir} DIRECTORY)
+
+      # Detect and handle swiftly-managed hosts.
+      if(swift_bin_dir MATCHES ".*/swiftly/bin")
+        execute_process(COMMAND swiftly use --print-location
+          OUTPUT_VARIABLE swiftly_dir
+          ERROR_VARIABLE err)
+        if(err)
+          message(SEND_ERROR "Failed to find swiftly Swift compiler")
+        endif()
+        string(STRIP "${swiftly_dir}" swiftly_dir)
+        set(swift_dir "${swiftly_dir}/usr")
+      endif()
+
       set(bs_lib_dir "${swift_dir}/lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
     endif()
   endif()
diff --git a/docs/ABI/KeyPaths.md b/docs/ABI/KeyPaths.md
index 7adf350258ee5..d742ab50c5296 100644
--- a/docs/ABI/KeyPaths.md
+++ b/docs/ABI/KeyPaths.md
@@ -92,7 +92,7 @@ Value in bits 24...30 | Description
 - A **class stored property** component, when given a reference to a class
   instance, can project the component value inside the class instance at
   a fixed offset. The *payload*
-  *payload* contains the offset in bytes of the projected field from the
+  contains the offset in bytes of the projected field from the
   address point of the object, or the special value `0xFF_FFFF`, which
   indicates that the offset is too large to pack into the payload and is stored
   in the next 32 bits after the header.
diff --git a/docs/ABI/Mangling.rst b/docs/ABI/Mangling.rst
index 1dba89461ded3..c4beec306e9cb 100644
--- a/docs/ABI/Mangling.rst
+++ b/docs/ABI/Mangling.rst
@@ -66,9 +66,9 @@ part of a symbolic reference.
 
   symbolic-reference ::= [\x01-\x17] .{4} // Relative symbolic reference
    #if sizeof(void*) == 8
-     symbolic-reference ::= [\x18-\x1F] .{8} // Absolute symbolic reference
+     symbolic-reference ::= [\x18-\x1F] .{8} // Absolute symbolic reference for 64-bit pointers
    #elif sizeof(void*) == 4
-     symbolic-reference ::= [\x18-\x1F] .{4} // Absolute symbolic reference
+     symbolic-reference ::= [\x18-\x1F] .{4} // Absolute symbolic reference for 32-bit pointers
    #endif
 
 Symbolic references are only valid in compiler-emitted metadata structures
@@ -110,7 +110,7 @@ The following symbolic reference kinds are currently implemented:
    #endif
 
    #if SWIFT_RUNTIME_VERSION >= 5.TBD
-    objective-c-protocol-relative-reference  ::=  `\x0C`  .{4} // Reference points directly to a objective-c protcol reference
+    objective-c-protocol-relative-reference  ::=  '\x0C'  .{4} // Reference points directly to a objective-c protcol reference
    #endif
 
 A mangled name may also include ``\xFF`` bytes, which are only used for
@@ -151,7 +151,7 @@ Globals
   global ::= protocol 'Hr'               // protocol descriptor runtime record
   global ::= nominal-type 'Hn'           // nominal type descriptor runtime record
   #if SWIFT_RUNTIME_VERSION >= 5.1
-    global ::= opaque-type 'Ho'          // opaque type descriptor runtime record
+    global ::= opaque-type-decl-name 'Ho' // opaque type descriptor runtime record
   #endif
   global ::= protocol-conformance 'Hc'   // protocol conformance runtime record
   global ::= global 'HF'                 // accessible function runtime record
@@ -250,14 +250,11 @@ types where the metadata itself has unknown layout.)
   global ::= global specialization       // function specialization
   global ::= global 'Tm'                 // merged function
   global ::= entity                      // some identifiable thing
-  global ::= from-type to-type generic-signature? 'TR'  // reabstraction thunk
-  global ::= impl-function-type type 'Tz' index? // objc-to-swift-async completion handler block implementation
-  global ::= impl-function-type type 'TZ' index? // objc-to-swift-async completion handler block implementation (predefined by runtime)
-  global ::= from-type to-type generic-signature? 'TR'  // reabstraction thunk
-  global ::= impl-function-type type generic-signature? 'Tz'     // objc-to-swift-async completion handler block implementation
-  global ::= impl-function-type type generic-signature? 'TZ'     // objc-to-swift-async completion handler block implementation (predefined by runtime)
-  global ::= from-type to-type self-type generic-signature? 'Ty'  // reabstraction thunk with dynamic 'Self' capture
-  global ::= from-type to-type generic-signature? 'Tr'  // obsolete mangling for reabstraction thunk
+  global ::= type type generic-signature? 'TR'  // reabstraction thunk
+  global ::= impl-function-type type generic-signature? 'Tz' index?    // objc-to-swift-async completion handler block implementation
+  global ::= impl-function-type type generic-signature? 'TZ' index?    // objc-to-swift-async completion handler block implementation predefined by runtime
+  global ::= type type type generic-signature? 'Ty'  // reabstraction thunk with dynamic 'Self' capture
+  global ::= type type generic-signature? 'Tr'  // obsolete mangling for reabstraction thunk
   global ::= entity generic-signature? type type* 'TK' // key path getter
   global ::= entity generic-signature? type type* 'Tk' // key path setter
   global ::= entity generic-signature? type type* 'Tkmu' // key path unapplied method
@@ -266,9 +263,9 @@ types where the metadata itself has unknown layout.)
   global ::= type generic-signature 'Th' // key path hasher
   global ::= global generic-signature? 'TJ' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' // autodiff function
   global ::= global generic-signature? 'TJV' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' // autodiff derivative vtable thunk
-  global ::= from-type to-type 'TJO' AUTODIFF-FUNCTION-KIND // autodiff self-reordering reabstraction thunk
-  global ::= from-type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff linear map subset parameters thunk
-  global ::= global to-type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff derivative function subset parameters thunk
+  global ::= type type 'TJO' AUTODIFF-FUNCTION-KIND // autodiff self-reordering reabstraction thunk
+  global ::= type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff linear map subset parameters thunk
+  global ::= global type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff derivative function subset parameters thunk
 
   global ::= protocol 'TL'               // protocol requirements base descriptor
   global ::= assoc-type-name 'Tl'        // associated type descriptor
@@ -280,9 +277,9 @@ types where the metadata itself has unknown layout.)
   REABSTRACT-THUNK-TYPE ::= 'R'          // reabstraction thunk
   REABSTRACT-THUNK-TYPE ::= 'r'          // reabstraction thunk (obsolete)
 
-  global ::= reabstraction-thunk type 'TU' // reabstraction thunk with global actor constraint
+  global ::= global type 'TU' // reabstraction thunk with global actor constraint
 
-The `from-type` and `to-type` in a reabstraction thunk helper function
+All reabstraction thunks have the "from" and "to" types in that order, and
 are always non-polymorphic ``<impl-function-type>`` types.
 
 ::
@@ -331,6 +328,7 @@ with a differentiable function used for differentiable programming.
   global ::= generic-signature? type 'WOe' // Outlined consume
   global ::= generic-signature? type 'WOr' // Outlined retain
   global ::= generic-signature? type 'WOs' // Outlined release
+  global ::= generic-signature? type 'WOB' // Outlined initializeWithTake, not using value witness
   global ::= generic-signature? type 'WOb' // Outlined initializeWithTake
   global ::= generic-signature? type 'WOc' // Outlined initializeWithCopy
   global ::= generic-signature? type 'WOC' // Outlined initializeWithCopy, not using value witness
@@ -340,9 +338,9 @@ with a differentiable function used for differentiable programming.
   global ::= generic-signature? type 'WOF' // Outlined assignWithCopy, not using value witness
   global ::= generic-signature? type 'WOh' // Outlined destroy
   global ::= generic-signature? type 'WOH' // Outlined destroy, not using value witness
-  global ::= generic-signature? type 'WOi` // Outlined store enum tag
-  global ::= generic-signature? type 'WOj` // Outlined enum destructive project
-  global ::= generic-signature? type 'WOg` // Outlined enum get tag
+  global ::= generic-signature? type 'WOi' // Outlined store enum tag
+  global ::= generic-signature? type 'WOj' // Outlined enum destructive project
+  global ::= generic-signature? type 'WOg' // Outlined enum get tag
 
 Entities
 ~~~~~~~~
@@ -356,8 +354,10 @@ Entities
   curry-thunk ::= 'Tc'
 
   label-list ::= empty-list            // represents complete absence of parameter labels
-  label-list ::= ('_' | identifier)*   // '_' is inserted as placeholder for empty label,
+  label-list ::= label*   // '_' is inserted as placeholder for empty label,
                                        // since the number of labels should match the number of parameters
+  label ::= '_'                        // empty label
+  label ::= identifier                 // label
 
   // The leading type is the function type
   entity-spec ::= label-list type file-discriminator? 'fC'      // allocating constructor
@@ -368,6 +368,7 @@ Entities
   entity-spec ::= entity 'fa'                // runtime discoverable attribute generator
   entity-spec ::= 'fi'                       // non-local variable initializer
   entity-spec ::= 'fP'                       // property wrapper backing initializer
+  entity-spec ::= 'fF'                       // property wrapped field init accessor
   entity-spec ::= 'fW'                       // property wrapper init from projected value
   entity-spec ::= 'fD'                       // deallocating destructor; untyped
   entity-spec ::= 'fZ'                       // isolated deallocating destructor; untyped
@@ -400,6 +401,8 @@ Entities
   ACCESSOR ::= 'p'                           // pseudo accessor referring to the storage itself
   ACCESSOR ::= 'x'                           // modify
   ACCESSOR ::= 'y'                           // read
+  ACCESSOR ::= 'b'                           // borrow
+  ACCESSOR ::= 'z'                           // mutate
 
   ADDRESSOR-KIND ::= 'u'                     // unsafe addressor (no owner)
   ADDRESSOR-KIND ::= 'O'                     // owning addressor (non-native owner), not used anymore
@@ -601,6 +604,8 @@ Types
 
   any-generic-type ::= standard-substitutions
 
+  nominal-type ::= any-generic-type              // nominal type
+
   standard-substitutions ::= 'S' KNOWN-TYPE-KIND       // known nominal type substitution
   standard-substitutions ::= 'S' NATURAL KNOWN-TYPE-KIND    // repeated known type substitutions of the same kind
 
@@ -723,8 +728,9 @@ Types
   type ::= '$' 'n'? INDEX                    // integer type
 #endif
 
-  bound-generic-type ::= type 'y' (type* '_')* type* retroactive-conformance* 'G'   // one type-list per nesting level of type
+  bound-generic-type ::= type bound-generic-args 'G'   // one type-list per nesting level of type
   bound-generic-type ::= substitution
+  bound-generic-args ::= 'y' (type* '_')* type* retroactive-conformance* // generic arguments
 
   FUNCTION-KIND ::= 'f'                      // @thin function type
   FUNCTION-KIND ::= 'U'                      // uncurried function type (currently not used)
@@ -737,7 +743,7 @@ Types
   FUNCTION-KIND ::= 'A'                      // @auto_closure function type (escaping)
   FUNCTION-KIND ::= 'E'                      // function type (noescape)
 
-  C-TYPE ::= NATURAL CHAR*                   // raw Itanium mangling
+  C-TYPE ::= NATURAL IDENTIFIER-STRING       // raw Itanium mangling
 
   function-signature ::= result-type params-type async? sendable? throws? differentiable? function-isolation? sending-result? // results and parameters
 
@@ -761,7 +767,7 @@ Types
     sending-result ::= 'YT'                  // -> sending T
   #endif
   #if SWIFT_RUNTIME_VERSION >= 6.2
-    function-isolation :== 'YC'              // @execution(caller) on function type
+    function-isolation :== 'YC'              // nonisolated(nonsending) on function type
   #endif
   differentiable ::= 'Yjf'                   // @differentiable(_forward) on function type
   differentiable ::= 'Yjr'                   // @differentiable(reverse) on function type
@@ -784,7 +790,7 @@ The 6.0 Swift runtime supports demangling ``sending-result``, but has a bug when
   METATYPE-REPR ::= 'o'                      // ObjC metatype representation
 
   existential-layout ::= protocol-list 'p'                 // existential layout
-  existential-layout ::= protocol-list superclass 'Xc'     // existential layout with superclass
+  existential-layout ::= protocol-list type 'Xc'           // existential layout with superclass
   existential-layout ::= protocol-list 'Xl'                // existential layout with AnyObject
 
   type ::= associated-type
@@ -800,11 +806,10 @@ The 6.0 Swift runtime supports demangling ``sending-result``, but has a bug when
   type ::= assoc-type-name 'Qz'                      // shortcut for 'Qyz'
   type ::= assoc-type-list 'QY' GENERIC-PARAM-INDEX  // associated type at depth
   type ::= assoc-type-list 'QZ'                      // shortcut for 'QYz'
-  type ::= opaque-type-decl-name bound-generic-args 'Qo' INDEX // opaque type
-  
-  type ::= pack-type 'Qe' INDEX              // pack element type
+
+  type ::= type 'Qe' INDEX              // pack element type
   
-  type ::= pattern-type count-type 'Qp'      // pack expansion type
+  type ::= type type 'Qp'         // pack expansion type (pattern, count)
   type ::= pack-element-list 'QP'            // pack type
   type ::= pack-element-list 'QS' DIRECTNESS // SIL pack type
 
@@ -813,7 +818,7 @@ The 6.0 Swift runtime supports demangling ``sending-result``, but has a bug when
   
   #if SWIFT_RUNTIME_VERSION >= 5.2
     type ::= type assoc-type-name 'Qx' // associated type relative to base `type`
-    type ::= type assoc-type-list 'QX' // associated type relative to base `type`
+    type ::= type assoc-type-list 'QX' // associated type relative to base `type` list
   #endif
 
   #if SWIFT_RUNTIME_VERSION >= 5.7
@@ -829,7 +834,7 @@ The 6.0 Swift runtime supports demangling ``sending-result``, but has a bug when
   associated-type ::= type identifier 'Qa' // associated type
 
   assoc-type-name ::= identifier                // associated type name without protocol
-  assoc-type-name ::= identifier protocol 'P'   //
+  assoc-type-name ::= identifier protocol 'P'   // associated type name with protocol
 
   empty-list ::= 'y'
 
@@ -844,7 +849,7 @@ mangled in to disambiguate.
   impl-function-type ::= type* 'I' FUNC-ATTRIBUTES '_'
   impl-function-type ::= type* generic-signature 'I' FUNC-ATTRIBUTES '_'
 
-  FUNC-ATTRIBUTES ::= PATTERN-SUBS? INVOCATION-SUBS? PSEUDO-GENERIC? CALLEE-ESCAPE? ISOLATION? DIFFERENTIABILITY-KIND? CALLEE-CONVENTION FUNC-REPRESENTATION? COROUTINE-KIND? SENDABLE? ASYNC? SENDING-RESULT? (PARAM-CONVENTION PARAM-DIFFERENTIABILITY?)* RESULT-CONVENTION* ('Y' PARAM-CONVENTION)* ('z' RESULT-CONVENTION RESULT-DIFFERENTIABILITY?)?
+  FUNC-ATTRIBUTES ::= PATTERN-SUBS? INVOCATION-SUB? PSEUDO-GENERIC? CALLEE-ESCAPE? ISOLATION? DIFFERENTIABILITY-KIND? CALLEE-CONVENTION FUNC-REPRESENTATION? COROUTINE-KIND? SENDABLE? ASYNC? SENDING-RESULT? (PARAM-CONVENTION PARAM-DIFFERENTIABILITY?)* RESULT-CONVENTION* ('Y' PARAM-CONVENTION)* ('z' RESULT-CONVENTION RESULT-DIFFERENTIABILITY?)?
 
   PATTERN-SUBS ::= 's'                       // has pattern substitutions
   INVOCATION-SUB ::= 'I'                     // has invocation substitutions
@@ -900,6 +905,15 @@ mangled in to disambiguate.
   PARAM-CONVENTION ::= 'p'                   // pack guaranteed
   PARAM-CONVENTION ::= 'm'                   // pack inout
 
+  #if SWIFT_RUNTIME_VERSION >= 6.0
+    SENDING-PARAM  ::= 'T'                   // sending parameter
+  #endif
+
+  #if SWIFT_RUNTIME_VERSION >= 6.2
+    ISOLATED-PARAM ::= 'I'                   // @isolated parameter
+    IMPLICIT-LEADING-PARAM ::= 'L'           // @implicit_leading parameter
+  #endif
+
   PARAM-DIFFERENTIABILITY ::= 'w'            // @noDerivative
 
   RESULT-CONVENTION ::= 'r'                  // indirect
@@ -952,10 +966,10 @@ productions:
 ::
 
   any-generic-type ::= context decl-name 'a'     // typealias type
-  type ::= base-type "XSq"                       // sugared Optional type
-  type ::= base-type "XSa"                       // sugared Array type
-  type ::= key-type value-type "XSD"             // sugared Dictionary type
-  type ::= count-type element-type "XSA"         // sugared InlineArray type
+  type ::= type 'XSq'                            // sugared Optional type
+  type ::= type 'XSa'                            // sugared Array type
+  type ::= type type 'XSD'                       // sugared Dictionary type (key, value)
+  type ::= type type 'XSA'                       // sugared InlineArray type (count, element)
 
 Generics
 ~~~~~~~~
@@ -1004,7 +1018,7 @@ Property behaviors are implemented using private protocol conformances.
       dependent-associated-conformance 'HA' DEPENDENT-CONFORMANCE-INDEX
 
   dependent-associated-conformance ::= type protocol
-  dependent-protocol-conformance ::= dependent-protocol-conformance opaque-type 'HO'
+  dependent-protocol-conformance ::= dependent-protocol-conformance type 'HO'
 
   pack-protocol-conformance ::= any-protocol-conformance-list 'HX'
 
@@ -1040,7 +1054,7 @@ now codified into the ABI; the index 0 is therefore reserved.
   generic-param-marker ::= generic-param-pack-marker
   generic-param-marker ::= generic-param-value-marker
 
-  generic-param-pack-marker ::= 'Rv' GENERIC_PARAM-INDEX   // generic parameter pack marker
+  generic-param-pack-marker ::= 'Rv' GENERIC-PARAM-INDEX   // generic parameter pack marker
 
 #if SWIFT_RUNTIME_VERSION >= 6.TBD
   generic-param-value-marker ::= type 'RV' GENERIC-PARAM-INDEX // generic parameter value marker
@@ -1084,9 +1098,9 @@ now codified into the ABI; the index 0 is therefore reserved.
   LAYOUT-CONSTRAINT ::= 'T'  // Trivial
   LAYOUT-CONSTRAINT ::= 'C'  // Class
   LAYOUT-CONSTRAINT ::= 'D'  // NativeClass
-  LAYOUT-CONSTRAINT ::= 'E' LAYOUT-SIZE-AND-ALIGNMENT  // Trivial of exact size
+  LAYOUT-CONSTRAINT ::= 'E' LAYOUT-SIZE-AND-ALIGNMENT  // Trivial of exact size and alignment
   LAYOUT-CONSTRAINT ::= 'e' LAYOUT-SIZE  // Trivial of exact size
-  LAYOUT-CONSTRAINT ::= 'M' LAYOUT-SIZE-AND-ALIGNMENT  // Trivial of size at most N bits
+  LAYOUT-CONSTRAINT ::= 'M' LAYOUT-SIZE-AND-ALIGNMENT  // Trivial of size and alignment at most N bits
   LAYOUT-CONSTRAINT ::= 'm' LAYOUT-SIZE  // Trivial of size at most N bits
   LAYOUT-CONSTRAINT ::= 'U'  // Unknown layout
   LAYOUT-CONSTRAINT ::= 'B' // BridgeObject
@@ -1230,7 +1244,7 @@ Substitutions
 ::
 
   substitution ::= 'A' INDEX                  // substitution of N+26
-  substitution ::= 'A' SUBST_IDX* LAST-SUBST-IDX    // One or more consecutive substitutions of N < 26
+  substitution ::= 'A' SUBST-IDX* LAST-SUBST-IDX    // One or more consecutive substitutions of N < 26
   SUBST-IDX ::= [a-z]
   SUBST-IDX ::= NATURAL [a-z]
   LAST-SUBST-IDX ::= [A-Z]
@@ -1281,14 +1295,14 @@ Numbers and Indexes
   INDEX ::= '_'                               // 0
   INDEX ::= NATURAL '_'                       // N+1
   NATURAL ::= [1-9] [0-9]*
-  NATURAL_ZERO ::= [0-9]+
+  NATURAL-ZERO ::= [0-9]+
 
 ``<INDEX>`` is a production for encoding numbers in contexts that can't
 end in a digit; it's optimized for encoding smaller numbers.
 
 ::
 
-  INDEX-SUBSET ::= ('S' | 'U')+
+  INDEX-SUBSET ::= [SU]+
 
 ``<INDEX-SUBSET>`` is encoded like a bit vector and is optimized for encoding
 indices with a small upper bound.
@@ -1348,6 +1362,7 @@ Some kinds need arguments, which precede ``Tf``.
   ARG-SPEC-KIND ::= 'n'                      // Unmodified argument
   ARG-SPEC-KIND ::= 'c'                      // Consumes n 'type' arguments which are closed over types in argument order
                                              // and one 'identifier' argument which is the closure symbol name
+  ARG-SPEC-KIND ::= 'C' NATURAL-ZERO         // the same closure as a previous argument <n>
   ARG-SPEC-KIND ::= 'p' CONST-PROP           // Constant propagated argument
   ARG-SPEC-KIND ::= 'e' 'D'? 'G'? 'X'?       // Generic argument, with optional dead, owned=>guaranteed or exploded-specifier
   ARG-SPEC-KIND ::= 'd' 'G'? 'X'?            // Dead argument, with optional owned=>guaranteed or exploded-specifier
@@ -1358,14 +1373,15 @@ Some kinds need arguments, which precede ``Tf``.
 
   CONST-PROP ::= 'f'                         // Consumes one identifier argument which is a function symbol name
   CONST-PROP ::= 'g'                         // Consumes one identifier argument which is a global symbol name
-  CONST-PROP ::= 'i' NATURAL_ZERO            // 64-bit-integer
-  CONST-PROP ::= 'd' NATURAL_ZERO            // float-as-64-bit-integer
+  CONST-PROP ::= 'i' NATURAL-ZERO            // 64-bit-integer
+  CONST-PROP ::= 'd' NATURAL-ZERO            // float-as-64-bit-integer
   CONST-PROP ::= 's' ENCODING                // string literal. Consumes one identifier argument.
   CONST-PROP ::= 'k'                         // keypath. Consumes one identifier - the SHA1 of the keypath and two types (root and value).
+  CONST-PROP ::= 'S' CONST-PROP*             // struct with operands. Consumes one type argument - the struct type.
 
   ENCODING ::= 'b'                           // utf8
   ENCODING ::= 'w'                           // utf16
-  ENCODING ::= 'c'                           // utf16
+  ENCODING ::= 'c'                           // objc
 
 If the first character of the string literal is a digit ``[0-9]`` or an
 underscore ``_``, the identifier for the string literal is prefixed with an
diff --git a/docs/Android.md b/docs/Android.md
index 879a5d5d998d3..918909b07756f 100644
--- a/docs/Android.md
+++ b/docs/Android.md
@@ -22,21 +22,17 @@ on an Android device, it takes a lot more than just the Swift stdlib to write
 an app. You'd need some sort of framework to build a user interface for your
 application, which the Swift stdlib does not provide.
 
-Alternatively, one could theoretically call into Java interfaces from Swift,
-but unlike as with Objective-C, the Swift compiler does nothing to facilitate
-Swift-to-Java bridging.
-
 ## Prerequisites
 
 To follow along with this guide, you'll need:
 
 1. A Linux environment capable of building Swift from source, preferably
-   Ubuntu 22.04 or Ubuntu 20.04. Before attempting to build for Android,
+   Ubuntu 24.04 or Ubuntu 22.04. Before attempting to build for Android,
    please make sure you are able to build for Linux by following the
    instructions in the Swift project README.
 2. The latest build of the Swift compiler for your Linux distro, available at
-   https://www.swift.org/download/ or sometimes your distro package manager.
-3. The latest version of the Android LTS NDK (r27c at the time of this writing),
+   https://www.swift.org/install/linux/ or sometimes your distro package manager.
+3. The latest version of the Android LTS NDK (r27d at the time of this writing),
    available to download here:
    https://developer.android.com/ndk/downloads
 4. An Android device with remote debugging enabled or the emulator. We require
@@ -54,9 +50,9 @@ and the prebuilt Swift toolchain (add --skip-early-swift-driver if you already
 have a Swift toolchain in your path):
 
 ```
-$ NDK_PATH=path/to/android-ndk-r27c
-$ SWIFT_PATH=path/to/swift-DEVELOPMENT-SNAPSHOT-2024-11-09-a-ubuntu22.04/usr/bin
-$ git checkout swift-DEVELOPMENT-SNAPSHOT-2024-11-09-a
+$ NDK_PATH=path/to/android-ndk-r27d
+$ SWIFT_PATH=path/to/swift-DEVELOPMENT-SNAPSHOT-2025-08-07-a-ubuntu24.04/usr/bin
+$ git checkout swift-DEVELOPMENT-SNAPSHOT-2025-08-07-a
 $ utils/build-script \
     -R \                                       # Build in ReleaseAssert mode.
     --android \                                # Build for Android.
@@ -83,11 +79,12 @@ Then use the standalone Swift stdlib from the previous step to compile a Swift
 source file, targeting Android:
 
 ```
-$ NDK_PATH="path/to/android-ndk-r27c"
-$ SWIFT_PATH=path/to/swift-DEVELOPMENT-SNAPSHOT-2024-11-09-a-ubuntu22.04/usr/bin
+$ NDK_PATH="path/to/android-ndk-r27d"
+$ SWIFT_PATH=path/to/swift-DEVELOPMENT-SNAPSHOT-2025-08-07-a-ubuntu24.04/usr/bin
 $ $SWIFT_PATH/swiftc \                                               # The prebuilt Swift compiler you downloaded
                                                                      # The location of the tools used to build Android binaries
     -tools-directory ${NDK_PATH}/toolchains/llvm/prebuilt/linux-x86_64/bin/ \
+    -disallow-use-new-driver \                                       # Work around a bug in the driver, a fix is in the works
     -target aarch64-unknown-linux-android21 \                        # Targeting Android aarch64 at API 21
     -sdk ${NDK_PATH}/toolchains/llvm/prebuilt/linux-x86_64/sysroot \ # The SDK is the Android unified sysroot and the resource-dir is where you just built the Swift stdlib.
     -resource-dir build/Ninja-ReleaseAssert/swift-linux-x86_64/lib/swift
@@ -135,7 +132,7 @@ $ adb push build/Ninja-ReleaseAssert/swift-linux-x86_64/lib/swift/android/libBlo
 In addition, you'll also need to copy the Android NDK's libc++:
 
 ```
-$ adb push /path/to/android-ndk-r27c/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib/aarch64-linux-android/libc++_shared.so /data/local/tmp
+$ adb push /path/to/android-ndk-r27d/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib/aarch64-linux-android/libc++_shared.so /data/local/tmp
 ```
 
 Finally, you'll need to copy the `hello` executable you built in the
@@ -178,7 +175,7 @@ $ utils/build-script \
   -R \                               # Build in ReleaseAssert mode.
   -T \                               # Run all tests, including on the Android device (add --host-test to only run Android tests on the Linux host).
   --android \                        # Build for Android.
-  --android-ndk ~/android-ndk-r27c \  # Path to an Android NDK.
+  --android-ndk ~/android-ndk-r27d \  # Path to an Android NDK.
   --android-arch aarch64 \           # Optionally specify Android architecture, alternately armv7 or x86_64
   --android-api-level 21
 ```
diff --git a/docs/ContinuousIntegration.md b/docs/ContinuousIntegration.md
index 7660ab4f91c8d..b7885cc507288 100644
--- a/docs/ContinuousIntegration.md
+++ b/docs/ContinuousIntegration.md
@@ -126,6 +126,7 @@ A validation test on Linux does the following:
 Platform        | Comment | Check Status
 ------------    | ------- | ------------
 macOS platform  | @swift-ci Please benchmark       | Swift Benchmark on macOS Platform (many runs - rigorous)
+macOS platform (Apple Silicon) | @swift-ci Apple Silicon benchmark | Swift Benchmark on macOS Platform using Apple Silicon (many runs - rigorous)
 macOS platform  | @swift-ci Please smoke benchmark | Swift Benchmark on macOS Platform (few runs - soundness)
 
 ### Linting
@@ -160,10 +161,9 @@ You can also build a toolchain for a specific Linux distribution
 Distro         | Comment                                          | Check Status
 -------------- | ------------------------------------------------ | ----------------------------------------------
 UBI9           | @swift-ci Please Build Toolchain UBI9            | Swift Build Toolchain UBI9 (x86_64)
-CentOS 7       | @swift-ci Please Build Toolchain CentOS 7        | Swift Build Toolchain CentOS 7 (x86_64)
-Ubuntu 18.04   | @swift-ci Please Build Toolchain Ubuntu 18.04    | Swift Build Toolchain Ubuntu 18.04 (x86_64)
 Ubuntu 20.04   | @swift-ci Please Build Toolchain Ubuntu 20.04    | Swift Build Toolchain Ubuntu 20.04 (x86_64)
 Ubuntu 22.04   | @swift-ci Please Build Toolchain Ubuntu 22.04    | Swift Build Toolchain Ubuntu 22.04 (x86_64)
+Ubuntu 24.04   | @swift-ci Please Build Toolchain Ubuntu 24.04    | Swift Build Toolchain Ubuntu 24.04 (x86_64)
 Amazon Linux 2 | @swift-ci Please Build Toolchain Amazon Linux 2  | Swift Build Toolchain Amazon Linux 2 (x86_64)
 
 ### Build and Test Stdlib against Snapshot Toolchain
diff --git a/docs/Diagnostics.md b/docs/Diagnostics.md
index 6acf30d89160e..b40f632f0f2ec 100644
--- a/docs/Diagnostics.md
+++ b/docs/Diagnostics.md
@@ -38,10 +38,26 @@ Clang also has a kind of diagnostic called a "remark", which represents informat
 
 - When applicable, phrase diagnostics as rules rather than reporting that the compiler failed to do something. Example:
 
-  - Normal: "cannot call 'super.init' outside of an initializer"
-  - Better: "'super.init' cannot be called outside of an initializer"
-
-- When referring to attributes by name, use *either* "the 'foo' attribute" or "'@foo'", rather than "the '@foo' attribute".
+  - Normal: `cannot call 'super.init' outside of an initializer`
+  - Better: `'super.init' cannot be called outside of an initializer`
+
+- Use `'` to quote attributes, symbol names, and any other text that is
+  referred to as code or a token.
+  Some idiomatic Swift tokens, such as `protocol`, by themselves are or appear
+  in Swift terms of art.
+  Terms of art are written in plain text and must not be quoted.
+  If you are not certain whether a Swift token has an associated term of art,
+  consult the [book].
+  For example:
+  - `'mutating' is only valid on methods`, but
+    `cannot call mutating method on immutable value`.
+  - `'@autoclosure' only applies to function types`.
+  - `subscript access can throw but is not marked with 'try'`.
+  - `expected '{' after 'defer'`.
+  - `type 'S' does not conform to protocol 'Sequence'`.
+
+- When referring to attributes by name, use *either* `attribute 'foo'` or 
+  `'@foo'`, rather than `attribute '@foo'`.
 
 - Match the tone and phrasing of other diagnostics. Some common phrases:
 
@@ -53,6 +69,8 @@ Clang also has a kind of diagnostic called a "remark", which represents informat
 
 - If possible, it is best to include the name of the type or function that has the error, e.g. "non-actor type 'Nope' cannot ..." is better than "non-actor type cannot ...". It helps developers relate the error message to the specific type the error is about, even if the error would highlight the appropriate line / function in other ways. 
 
+[book]: https://docs.swift.org/swift-book/documentation/the-swift-programming-language
+
 ### Locations and Highlights ###
 
 - Diagnostics are always emitted at a particular line and column. Try to be specific.
@@ -98,6 +116,14 @@ Diagnostic group documentation should:
 - Include references to relevant chapters of _The Swift Programming Language_.
 - Be written in Markdown, but avoid excessive markup which negatively impacts the terminal UX.
 
+The diagnostic group documentation supports generating a DocC bundle for hosting. You can currently find the compiler diagnostics documentation at https://docs.swift.org/compiler/documentation/diagnostics/
+
+To generate this documentation locally, run the following command from the root of the repository:
+```
+docc preview --allow-arbitrary-catalog-directories userdocs/diagnostics
+```
+
+
 ### Quick-Start Guide for Contributing New Diagnostic Groups ###
 
 Adding new diagnostic groups is a great way to get familiar with the process of contributing to Swift, while also making a big impact!
@@ -109,7 +135,7 @@ To add a new diagnostics group:
     - An entry in a `Diagnostics*.def` file describing the diagnostic. If there are any closely related diagnostics the note should also be attached to, they can usually be found nearby.
     - Each point in the compiler source where the diagnostic is emitted. This can be helpful in determining the exact circumstances which cause it to be emitted.
 4. Add a new Markdown file in the `userdocs/diagnostics/` directory in the swift repository containing the documentation. When writing a note, keep the writing guidelines from the section above in mind. The existing notes in the directory are another useful guide.
-5. Create a new entry in `DiagnosticGroups.def` that provides the name for your new diagnostic group along with the name of the file you added in step (4).
+5. Create a new entry in `DiagnosticGroups.def` that provides the name for your new diagnostic group along with the name of the file you added in step (4), without an extension.
 6. Find each diagnostic you want to make part of this group in the various `Diagnostics*.def` files. For each diagnostic, replace the `ERROR` or `WARNING` with `GROUPED_ERROR` or `GROUPED_WARNING`, respectively, and put the diagnostic group name after the string literal for the diagnostic message.
 7. If possible, rebuild the compiler and try recompiling your test program. Your new diagnostic group should appear as `[#<group name>]` at the end of the diagnostic, with a link to the diagnostic file.
 8. That's it! The new diagnostic group is now ready to be submitted as a pull request on GitHub.
@@ -130,7 +156,10 @@ If you run into any issues or have questions while following the steps above, fe
 
 - `%%` - Emits a literal percent sign.
 
-There are several format specifiers that are specific to `Decl` parameters:
+The following subsections describe format specifiers that are specific to 
+diagnostic arguments of a given type.
+
+#### `Decl`
 
 - `%kind0` - Prefixes the declaration's name with its descriptive decl kind (e.g. `instance method 'foo(x:)'`).
 
@@ -140,6 +169,11 @@ There are several format specifiers that are specific to `Decl` parameters:
 
 - `%kindbase0` - Combines `kind` and `base` (e.g. `instance method 'foo'`).
 
+#### `TypeAttribute`
+
+- `%kind0` - Replaced with `attribute 'foo'`, whereas `%0` is replaced with
+  `'@foo'`.
+
 Note: If your diagnostic could apply to accessors, be careful how you format the declaration's name; accessors have an empty name, so you need to display their accessor kind and the name of their storage decl instead. Inserting the name with a `Decl *` parameter will handle these complications automatically; if you want to use `DeclName` or `Identifier` instead, you'll probably need a separate version of the diagnostic for accessors. 
 
 ### Diagnostic Verifier ###
diff --git a/docs/EmbeddedSwift/ABI.md b/docs/EmbeddedSwift/ABI.md
index f3be5ec377fdc..a5542b068a54c 100644
--- a/docs/EmbeddedSwift/ABI.md
+++ b/docs/EmbeddedSwift/ABI.md
@@ -1,58 +1,3 @@
 # Embedded Swift -- ABI
 
-**⚠️ Embedded Swift is experimental. This document might be out of date with latest development.**
-
-**‼️ Use the latest downloadable 'Trunk Development' snapshot from swift.org to use Embedded Swift. Public releases of Swift do not yet support Embedded Swift.**
-
-For an introduction and motivation into Embedded Swift, please see "[A Vision for Embedded Swift](https://github.com/swiftlang/swift-evolution/blob/main/visions/embedded-swift.md)", a Swift Evolution document highlighting the main goals and approaches.
-
-## ABI stability
-
-The ABI of code generated by Embedded Swift is not currently stable. For a concrete compiler version, it will be consistent, but do not mix code built with different compiler versions.
-
-Similarly, do not mix Embedded Swift code with full Swift code, as the ABIs are different. Details are described in the following sections.
-
-## Symbol mangling under Embedded Swift
-
-Since Swift 5.0, the stable ABI mangling schema uses the `$s` prefix on all Swift symbols. Because Embedded Swift's ABI differs from the stable ABI, and furthermore because it's not expected to be stable, Embedded Swift uses a `$e` mangling prefix. The logic and structure of the mangling stays the same, the only difference is the prefix.
-
-## Calling convention of Embedded Swift
-
-As of today, Embedded Swift has identical calling convention to full Swift. However, this does not need to continue in the future, and there should not be expectations that the ABI of Embedded Swift is compatible with full Swift.
-
-The compiler respects the ABIs and calling conventions of C and C++ when interoperating with code in those languages. Calling C/C++ functions from Embedded Swift code is supported, and similarly exporting Swift code via `@_extern`, `@_cdecl` or `@_expose` will match the right calling conventions that C/C++ expects.
-
-## Metadata ABI of Embedded Swift
-
-Embedded Swift eliminates almost all metadata compared to full Swift. However, class and existential metadata are still used, because those serve as vtables and witness tables for dynamic dispatch of methods to implement runtime polymorphism with classes and existentials.
-
-### Class Metadata ABI
-
-The layout of Embedded Swift's class metadata is *different* from full Swift:
-
-- The **super pointer** pointing to the class metadata record for the superclass is stored at **offset 0**. If the class is a root class, it is null.
-- The **destructor pointer** is stored at **offset 1**. This function is invoked by Swift's deallocator when the class instance is destroyed.
-- The **ivar destroyer** is stored at **offset 2**. This function is invoked to destroy instance members when creation of the object is cancelled (e.g. in a failable initializer).
-- Lastly, the **vtable** is stored at **offset 3**: For each Swift class in the class's inheritance hierarchy, in order starting
-  from the root class and working down to the most derived class, the function pointers to the implementation of every method of the class in declaration order in stored.
-
-### Witness Tables ABI
-
-The layout of Embedded Swift's witness tables is *different* from full Swift:
-
-- The first word is always a null pointer (TODO: it can be eliminated)
-- The following words are witness table entries which can be one of the following:
-  - A method witness: a pointer to the witness function.
-  - An associated conformance witness: a pointer to the witness table of the associated conformance
-
-Note that witness tables in Embedded Swift do not contain associated type entries.
-
-Witness functions are always specialized for concrete types. This also means that parameters and return values are passed directly (if possible).
-
-## Heap object layout in Embedded Swift
-
-Heap objects have the following layout in Embedded Swift:
-
-- The **isa pointer** (pointer to the class metadata) is stored at **offset 0**.
-- The **refcount** is stored inline at **offset 1**.
-- Normal stored properties follow.
+Embedded Swift documentation has moved to: [Swift.org](https://docs.swift.org/embedded/documentation/embedded).
diff --git a/docs/EmbeddedSwift/EmbeddedSwiftStatus.md b/docs/EmbeddedSwift/EmbeddedSwiftStatus.md
index 07b017d436037..df2f798634b21 100644
--- a/docs/EmbeddedSwift/EmbeddedSwiftStatus.md
+++ b/docs/EmbeddedSwift/EmbeddedSwiftStatus.md
@@ -1,77 +1,3 @@
 # Embedded Swift -- Status
 
-**⚠️ Embedded Swift is experimental. This document might be out of date with latest development.**
-
-**‼️ Use the latest downloadable 'Trunk Development' snapshot from swift.org to use Embedded Swift. Public releases of Swift do not yet support Embedded Swift.**
-
-For an introduction and motivation into Embedded Swift, please see "[A Vision for Embedded Swift](https://github.com/swiftlang/swift-evolution/blob/main/visions/embedded-swift.md)", a Swift Evolution document highlighting the main goals and approaches.
-
-## Embedded Swift Language Features
-
-| **Language Feature**                                  | **Currently Supported In Embedded Swift**                                          |
-|-------------------------------------------------------|------------------------------------------------------------------------------------|
-| *Anything not listed below*                           | Yes                                                                                |
-| Library Evolution (resilience)                        | No, intentionally unsupported long-term                                            |
-| Objective-C interoperability                          | No, intentionally unsupported long-term                                            |
-| Non-WMO builds                                        | No, intentionally unsupported long-term (WMO should be used)                       |
-| Existentials (values of protocol types)               | Only class-bound existentials (for protocols derived from AnyObject) are supported |
-| Any                                                   | No, currently disallowed                                                           |
-| AnyObject                                             | Yes                                                                                |
-| Metatypes                                             | No, currently only allowed as unused arguments (type hints)                        |
-| Untyped throwing                                      | No, intentionally unsupported long-term (typed throwing should be used instead)    |
-| Weak references, unowned references                   | No                                                                                 |
-| Non-final generic class methods                       | No, intentionally unsupported long-term                                            |
-| Parameter packs (variadic generics)                   | No, not yet supported                                                              |
-
-## Embedded Standard Library Breakdown
-
-This status table describes which of the following standard library features can be used in Embedded Swift:
-
-| **Swift Standard Library Feature**                         | **Currently Supported In Embedded Swift?**          |
-|------------------------------------------------------------|-----------------------------------------------------|
-| Array (dynamic heap-allocated container)                   | Yes    |                                      
-| Array slices                                               | Yes    |                                      
-| assert, precondition, fatalError                           | Partial, only StaticStrings can be used as a failure message |
-| Bool, Integer types, Float types                           | Yes    |
-| Codable, Encodable, Decodable                              | No     |
-| Collection + related protocols                             | Yes    |
-| Collection algorithms (sort, reverse)                      | Yes    |
-| CustomStringConvertible, CustomDebugStringConvertible      | Yes, except those that require reflection (e.g. Array's .description)     |
-| Dictionary (dynamic heap-allocated container)              | Yes    |
-| Floating-point conversion to string                        | No     |
-| Floating-point parsing                                     | No     |
-| FixedWidthInteger + related protocols                      | Yes    |
-| Hashable, Equatable, Comparable protocols                  | Yes    |
-| InputStream, OutputStream                                  | No     |
-| Integer conversion to string                               | Yes    |
-| Integer parsing                                            | No     |
-| KeyPaths                                                   | Partial (only compile-time constant key paths to stored properties supported, only usable in MemoryLayout and UnsafePointer APIs)     |
-| Lazy collections                                           | No     |
-| ManagedBuffer                                              | Yes    |
-| Mirror (runtime reflection)                                | No, intentionally unsupported long-term |
-| Objective-C bridging                                       | No, intentionally unsupported long-term |
-| Optional                                                   | Yes    |
-| print / debugPrint                                         | Partial (only String, string interpolation, StaticStrings, integers, pointers and booleans) |
-| Range, ClosedRange, Stride                                 | Yes    |
-| Result                                                     | Yes    |
-| Set (dynamic heap-allocated container)                     | Yes    |                                      
-| SIMD types                                                 | Yes    |
-| StaticString                                               | Yes    |
-| String (dynamic)                                           | Yes    |
-| String interpolations                                      | Partial (only strings, integers, booleans, and custom types that are CustomStringConvertible can be interpolated)    |
-| Unicode                                                    | Yes    |
-| Unsafe\[Mutable\]\[Raw\]\[Buffer\]Pointer                  | Yes    |
-| VarArgs                                                    | No     |
-
-## Non-stdlib Features
-
-This status table describes which of the following Swift features can be used in Embedded Swift:
-
-| **Swift Feature**                                          | **Currently Supported In Embedded Swift?**          |
-|------------------------------------------------------------|-----------------------------------------------------|
-| Synchronization module                                     | Partial (only Atomic types, no Mutex)    |
-| Swift Concurrency                                          | Partial, experimental (basics of actors and tasks work in single-threaded concurrency mode) |
-| C interop                                                  | Yes    | 
-| C++ interop                                                | Yes    |
-| ObjC interop                                               | No, intentionally unsupported long-term |
-| Library Evolution                                          | No, intentionally unsupported long-term |
+Embedded Swift documentation has moved to: [Swift.org](https://docs.swift.org/embedded/documentation/embedded).
diff --git a/docs/EmbeddedSwift/Existentials.md b/docs/EmbeddedSwift/Existentials.md
new file mode 100644
index 0000000000000..e61d3a037f438
--- /dev/null
+++ b/docs/EmbeddedSwift/Existentials.md
@@ -0,0 +1,3 @@
+# Embedded Swift -- Existentials
+
+Embedded Swift documentation has moved to: [Swift.org](https://docs.swift.org/embedded/documentation/embedded).
diff --git a/docs/EmbeddedSwift/IntegratingWithSDKs.md b/docs/EmbeddedSwift/IntegratingWithSDKs.md
index 6a39248d79f89..a4f4dae4568a5 100644
--- a/docs/EmbeddedSwift/IntegratingWithSDKs.md
+++ b/docs/EmbeddedSwift/IntegratingWithSDKs.md
@@ -1,112 +1,3 @@
 # Embedded Swift -- Integrating with embedded SDKs
 
-**⚠️ Embedded Swift is experimental. This document might be out of date with latest development.**
-
-**‼️ Use the latest downloadable 'Trunk Development' snapshot from swift.org to use Embedded Swift. Public releases of Swift do not yet support Embedded Swift.**
-
-For an introduction and motivation into Embedded Swift, please see "[A Vision for Embedded Swift](https://github.com/swiftlang/swift-evolution/blob/main/visions/embedded-swift.md)", a Swift Evolution document highlighting the main goals and approaches.
-
-The following document sketches how to integrate Swift code into some popular embedded platforms' SDKs and build systems.
-
-## Integrating with Raspberry Pi Pico (W) build system:
-
-Development for [Raspberry Pi Pico and Pico W](https://www.raspberrypi.com/products/raspberry-pi-pico/) normally uses the [Pico SDK](https://github.com/raspberrypi/pico-sdk) and the vendor provides several [sample projects in the pico-examples repository](https://github.com/raspberrypi/pico-examples). The SDK and sample project setup is described in:
-
-- https://www.raspberrypi.com/documentation/microcontrollers/c_sdk.html#sdk-setup
-- https://datasheets.raspberrypi.com/pico/getting-started-with-pico.pdf
-
-Before trying to use Swift with the Pico SDK, make sure your environment works and can build the provided C/C++ sample projects.
-
-### CMake setup with a bridging header
-
-The Pico SDK is using CMake as its build system, and so the simplest way to integrate with it is to also use CMake to build a Swift firmware application on top of the SDK and the libraries from it. The following describes an example set up of that on a "blinky" example (code that just blinks the built-in LED).
-
-Let's create a directory with a Swift source file, a bridging header, and a CMake definition file:
-
-```
-./SwiftPicoBlinky/Main.swift
-./SwiftPicoBlinky/BridgingHeader.h
-./SwiftPicoBlinky/CMakeLists.txt
-```
-
-In `Main.swift`, let's add basic logic to initialize the GPIO port for the Pico's built-in LED, and then turn it on and off in a loop:
-
-```swift
-@main
-struct Main {
-  static func main() {
-    let led = UInt32(PICO_DEFAULT_LED_PIN)
-    gpio_init(led)
-    gpio_set_dir(led, /*out*/true)
-    while true {
-      gpio_put(led, true)
-      sleep_ms(250)
-      gpio_put(led, false)
-      sleep_ms(250)
-    }
-  }
-}
-```
-
-Notice that we're using functions and variables defined in C in the Pico SDK. For that to be possible, the Swift compiler needs to have access to the C header files that define these functions and variables. The cleanest option would be to define a modulemap, but for simplicity let's just use a bridging header to make declarations visible in Swift without a module. `BridgingHeader.h` should contain:
-
-```c
-#pragma once
-
-#include "pico/stdlib.h"
-```
-
-Finally, we need to define the application's build rules in CMake that will be using CMake logic from the Pico SDK. The following content of `CMakeLists.txt` shows how to *manually call swiftc, the Swift compiler* instead of using the recently added CMake native support for Swift, so that we can see the full Swift compilation command.
-
-```cmake
-cmake_minimum_required(VERSION 3.13)
-include($ENV{PICO_SDK_PATH}/external/pico_sdk_import.cmake)
-
-project(swift-blinky)
-pico_sdk_init()
-execute_process(COMMAND xcrun -f swiftc OUTPUT_VARIABLE SWIFTC OUTPUT_STRIP_TRAILING_WHITESPACE)
-
-add_executable(swift-blinky)
-add_custom_command(
-    OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/_swiftcode.o
-    COMMAND
-        ${SWIFTC}
-        -target armv6m-none-none-eabi -Xcc -mfloat-abi=soft -Xcc -fshort-enums
-        -Xfrontend -function-sections -enable-experimental-feature Embedded -wmo -parse-as-library
-        $$\( echo '$<TARGET_PROPERTY:swift-blinky,INCLUDE_DIRECTORIES>' | tr '\;' '\\n' | sed -e 's/\\\(.*\\\)/-Xcc -I\\1/g' \)
-        $$\( echo '${CMAKE_C_IMPLICIT_INCLUDE_DIRECTORIES}'             | tr ' '  '\\n' | sed -e 's/\\\(.*\\\)/-Xcc -I\\1/g' \)
-        -import-bridging-header ${CMAKE_CURRENT_LIST_DIR}/BridgingHeader.h
-        ${CMAKE_CURRENT_LIST_DIR}/Main.swift
-        -c -o ${CMAKE_CURRENT_BINARY_DIR}/_swiftcode.o
-    DEPENDS
-        ${CMAKE_CURRENT_LIST_DIR}/BridgingHeader.h
-        ${CMAKE_CURRENT_LIST_DIR}/Main.swift
-)
-add_custom_target(swift-blinky-swiftcode DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/_swiftcode.o)
-
-target_link_libraries(swift-blinky
-    pico_stdlib hardware_uart hardware_gpio
-    ${CMAKE_CURRENT_BINARY_DIR}/_swiftcode.o
-)
-add_dependencies(swift-blinky swift-blinky-swiftcode)
-pico_add_extra_outputs(swift-blinky)
-```
-
-With these three files, we can now configure and build a Swift firmware for the Pico:
-
-```bash
-$ export TOOLCHAINS=org.swift.59202401301a
-$ export PICO_BOARD=pico
-$ export PICO_SDK_PATH=<path_to_pico_sdk>
-$ export PICO_TOOLCHAIN_PATH=<path_to_arm_toolchain>
-$ ls -al
--rw-r--r--   1 kuba  staff    39B Feb  2 22:08 BridgingHeader.h
--rw-r--r--   1 kuba  staff   1.3K Feb  2 22:08 CMakeLists.txt
--rw-r--r--   1 kuba  staff   262B Feb  2 22:08 Main.swift
-$ mkdir build
-$ cd build
-$ cmake -S ../ -B . -G Ninja
-$ ninja -v
-```
-
-This should produce several build artifacts in the `build/` subdirectory, include `swift-blinky.uf2`, which can be directly uploaded to the Pico by copying it into the fake Mass Storage Volume that the device presents when plugged over USB in BOOTSEL mode.
+Embedded Swift documentation has moved to: [Swift.org](https://docs.swift.org/embedded/documentation/embedded).
diff --git a/docs/EmbeddedSwift/NonFinalGenericMethods.md b/docs/EmbeddedSwift/NonFinalGenericMethods.md
new file mode 100644
index 0000000000000..2decd4dcca4d7
--- /dev/null
+++ b/docs/EmbeddedSwift/NonFinalGenericMethods.md
@@ -0,0 +1,3 @@
+# Embedded Swift -- Non-final generic methods
+
+Embedded Swift documentation has moved to: [Swift.org](https://docs.swift.org/embedded/documentation/embedded).
diff --git a/docs/EmbeddedSwift/README.md b/docs/EmbeddedSwift/README.md
new file mode 100644
index 0000000000000..b72ed93bd3bf5
--- /dev/null
+++ b/docs/EmbeddedSwift/README.md
@@ -0,0 +1,3 @@
+# Embedded Swift
+
+Embedded Swift documentation has moved to: [Swift.org](https://docs.swift.org/embedded/documentation/embedded).
diff --git a/docs/EmbeddedSwift/UserManual.md b/docs/EmbeddedSwift/UserManual.md
index 3ae79e375f7ea..0ee458817daf4 100644
--- a/docs/EmbeddedSwift/UserManual.md
+++ b/docs/EmbeddedSwift/UserManual.md
@@ -1,278 +1,3 @@
 # Embedded Swift -- User Manual
 
-**⚠️ Embedded Swift is experimental. This document might be out of date with latest development.**
-
-**‼️ Use the latest downloadable 'Trunk Development' snapshot from swift.org to use Embedded Swift. Public releases of Swift do not yet support Embedded Swift.**
-
-For an introduction and motivation into Embedded Swift, please see "[A Vision for Embedded Swift](https://github.com/swiftlang/swift-evolution/blob/main/visions/embedded-swift.md)", a Swift Evolution document highlighting the main goals and approaches.
-
-The following document explains how to use Embedded Swift's support in the Swift compiler and toolchain.
-
-## What Embedded Swift is, and what it isn't
-
-- Embedded Swift **is** a way to produce small and freestanding binaries (with no, or trivial dependencies).
-- Embedded Swift **is not** a complete one-click solution to program all embedded boards and MCUs.
-- Embedded Swift **is** a compilation model that's analogous to a traditional C compiler in the sense that the compiler produces an object file (.o) that can be simply linked with your existing code, and it's not going to require you to port any libraries or runtimes.
-- Embedded Swift **is not** a HAL, it's not an SDK for development, it's not a set of libraries to program peripherals using high-level APIs. It's instead a compilation mode that's suitable for creating these components.
-
-## Using Embedded Swift
-
-A typical setup and build + run cycle for an embedded development board involves:
-
-- (1) Getting an SDK with the C compilers, headers and libraries for the target
-- (2) Building the C source code, and Swift source code into object files.
-- (3) Linking all the libraries, C object files, and Swift object files.
-- (4) Post-processing the linked firmware into a flashable format (UF2, BIN, HEX, or bespoke formats)
-- (5) Uploading the flashable binary to the board over a USB cable using some vendor-provided JTAG/SWD tool, by copying it to a fake USB Mass Storage volume presented by the board or a custom platform bootloader.
-- (6) Restarting the board, observing physical effects of the firmware (LEDs light up) or UART output over USB, or presence on network, etc.
-
-Most of these steps are out of scope for this document, instead refer to the vendor provided documentation. This document only focuses on (2) from the list above, and it's important that you first get familiar with the details of firmware development for your board without Swift in the mix. Even if you want to build a completely pure Swift firmware, you are still going to need the vendor provided tooling for linking, post-processing, uploading, etc.
-
-## Building code using Embedded Swift
-
-A basic way to build a set of Swift source files in Embedded Swift mode, is to simply give the compiler (1) a target triple, (2) the `-enable-experimental-feature Embedded` flag, (3) the set of source files that form the input module:
-
-```bash
-$ swiftc -target <target triple> -enable-experimental-feature Embedded -wmo \
-  input1.swift input2.swift ... -c -o output.o
-```
-
-On macOS, it's common to have Xcode installed, which comes with a toolchain that does not support Embedded Swift yet. Unless you download, install, and activate a swift.org toolchain, you'll see this error:
-
-```bash
-$ swiftc input1.swift -enable-experimental-feature Embedded -wmo
-<unknown>:0: error: unable to load standard library for target 'arm64-apple-macosx15.0'
-```
-
-To resolve it, download and install a nightly toolchain from swift.org. Then, don't forget to activate it in your terminal by setting the `TOOLCHAINS` environment variable, for example with this command (if you installed into the `/Library` path):
-
-```bash
-$ export TOOLCHAINS=$(plutil -extract CFBundleIdentifier raw /Library/Developer/Toolchains/swift-latest.xctoolchain/Info.plist)
-```
-
-## Examples
-
-### Building Swift firmware for an embedded target
-
-To build Swift firmware (for now ignoring integration with SDKs, libraries and other pre-existing C code), we can use the `-target` argument to specify the CPU architecture. The target triple also decides whether the output object file will be an ELF file, or a Mach-O. For example:
-
-```bash
-# To build an ARMv7 Mach-O object file:
-$ swiftc -target armv7-apple-none-macho -enable-experimental-feature Embedded -wmo \
-  input1.swift input2.swift ... -c -o output.o
-
-# To build an ARMv7 ELF object file:
-$ swiftc -target armv7-none-none-eabi -enable-experimental-feature Embedded -wmo \
-  input1.swift input2.swift ... -c -o output.o
-```
-
-Additionally, you probably want to specify additional Clang and/or LLVM flags to get the compiler to produce code for the exact ISA and ABI you need for your target. 
-
-For example, a Raspberry Pi Pico / Pico W should target the ARMv6-M architecture via the `armv6m-*` target triple, but the `-mfloat-abi=soft` Clang option should also be used, and if you want to match ABI with libraries built with the GNU toolchain, you might also need `-fshort-enums`. To pass those to Swift, use the `-Xcc` prefix:
-
-```bash
-# To build an ELF object file for ARMv6-M with soft float ABI (floating-point arguments passed in integer registers) and "short enums":
-$ swiftc -target armv6m-none-none-eabi -enable-experimental-feature Embedded -wmo \
-   -Xcc -mfloat-abi=soft -Xcc -fshort-enums \
-  input1.swift input2.swift ... -c -o output.o
-```
-
-This might not be obvious: `-Xcc` flags are typically only used to alter behavior of the Clang importer, but passing flags to Clang this way also works to specify LLVM target options like selecting a specific CPU architecture (`-march`, `-mcpu`, `-mmcu`), FPU unit availability (`-mfpu`), which registers are used to pass floating-point values (`-mfloat-abi`), and others.
-
-### Integrating with embedded SDKs and build systems
-
-For details and concrete examples of how to integrate with existing SDKs, see [Embedded Swift -- Integrating with embedded SDKs](IntegratingWithSDKs.md).
-
-### Building a macOS Embedded Swift program:
-
-It's also possible to build in Embedded Swift mode for regular non-embedded operating systems, like macOS. This is very useful for testing purposes, or if you just want to observe and experiment with Embedded Swift. A simple source code like this:
-
-```swift
-print("Hello, embedded world!")
-```
-
-...can be compiled using the `-enable-experimental-feature Embedded` flag (the implicit `-target` matches the host OS):
-
-```bash
-$ xcrun swiftc hello.swift -enable-experimental-feature Embedded -wmo
-$ ./hello
-Hello, embedded world!
-```
-
-Note that the resulting executable is still a *dynamically-linked executable*, so it's not fully standalone in the embedded sense. Namely is still uses `putchar` from Libsystem. But the singular object file that was used to build this executable was produced by the compiler in the same fashion that a real embedded build would. If we ask the compiler and linker to minimize the size of the outputs and to remove any unused code, we can observe that the binary has no other dependencies other than `putchar` and that the machine code section is very small (172 bytes in the `__text` section):
-
-```bash
-$ xcrun swiftc hello.swift -enable-experimental-feature Embedded -wmo -Osize -Xlinker -dead_strip
-$ nm -um ./hello
-                 (undefined) external _putchar (from libSystem)
-$ size -m ./hello
-Segment __TEXT: 16384
-  Section __text: 172
-...
-```
-
-## Strings
-
-Both StaticString and String types are available in Embedded Swift. As is the case in desktop Swift, certain operations on strings require Unicode data tables for strict Unicode compliance. In Embedded Swift these data tables are provided as a separate static library (libUnicodeDataTables.a) that users need to link in manually – if they need to use these string operations. If the library is required, linking will fail due to missing on one or more of the following symbols:
-
-```
-_swift_stdlib_getAge
-_swift_stdlib_getBinaryProperties
-_swift_stdlib_getCaseMapping
-_swift_stdlib_getComposition
-_swift_stdlib_getDecompositionEntry
-_swift_stdlib_getGeneralCategory
-_swift_stdlib_getGraphemeBreakProperty
-_swift_stdlib_getMapping
-_swift_stdlib_getMphIdx
-_swift_stdlib_getNameAlias
-_swift_stdlib_getNormData
-_swift_stdlib_getNumericType
-_swift_stdlib_getNumericValue
-_swift_stdlib_getScalarBitArrayIdx
-_swift_stdlib_getScalarName
-_swift_stdlib_getScript
-_swift_stdlib_getScriptExtensions
-_swift_stdlib_getSpecialMapping
-_swift_stdlib_getWordBreakProperty
-_swift_stdlib_isLinkingConsonant
-_swift_stdlib_nfd_decompositions
-```
-
-To resolve this, link in the `libswiftUnicodeDataTables.a` that's in Swift toolchain's resource directory (`lib/swift/`) under the target triple that you're using:
-
-```bash
-$ swiftc <inputs> -target armv6m-none-none-eabi -enable-experimental-feature Embedded -wmo -c -o output.o
-$ ld ... -o binary output.o $(dirname `which swiftc`)/../lib/swift/embedded/armv6m-none-none-eabi/libswiftUnicodeDataTables.a
-```
-
-**Unicode data tables are required for (list not exhaustive):**
-
-- Comparing String objects for equality
-- Sorting Strings
-- Using String's hash values, and in particular using String as dictionary keys
-- Using String's `.count` property
-- Using Unicode-aware string processing APIs (`.split()`, iterating characters, indexing)
-- Using Unicode-aware conversion String APIs (`.uppercased()`, `.lowercased()`, etc.)
-
-**For contrast, unicode data tables are *not required for* (list not exhaustive):**
-
-- Using StaticString
-- Creating, concatenating, string interpolating, and printing String objects
-- Using `.utf8`, `.utf16`, and `.unicodeScalars` views of strings, including their .count property, using them as dictionary keys
-
-Manually linking `libswiftUnicodeDataTables.a` is required for several reasons, including acknowledging that the data tables are desirable: Since they have a non-negligible size, it's useful to be aware that you are using them.
-
-## Conditionalizing compilation for Embedded Swift
-
-It's often useful to have source code be compilable under both regular Swift and Embedded Swift. The following syntax is available for that (but note that as the rest of Embedded Swift, it's experimental, subject to change and not considered source stable):
-
-```swift
-func sayHello() {
-  #if hasFeature(Embedded)
-  print("I'm Embedded Swift")
-  #else
-  print("I'm regular Swift")
-  #endif
-}
-```
-
-Additionally, you can also use an attribute (also experimental, and not source stable) to make entire functions, types and other declarations unavailable in Embedded Swift. This can be particularly useful to explicitly mark your own code (and also entire types and conformances) that relies on features unavailable in Embedded Swift, e.g. the Any type or Codable -- it is explicitly allowed to use those in unavailable contexts:
-
-```swift
-@_unavailableInEmbedded
-func useAny(_: Any) { ... }
-
-@_unavailableInEmbedded
-extension MyStruct: Codable {
-  ...
-}
-```
-
-## Embedded Swift is a subset of Swift
-
-Embedded Swift is a subset of the Swift language, and some features are not available in Embedded Swift, however features are available, including: Generics, protocols, enums with associated values, tuples, optionals, classes (instances are allocated on the heap and refcounted just like in regular Swift), inheritance, runtime polymorphism, arrays (heap-allocated copy-on-write just like in regular Swift) and many more.
-
-Features that are not available:
-
-- **Not available**: Runtime reflection (`Mirror` APIs).
-- **Not available**: Values of protocol types ("existentials"), unless the protocol is restricted to be class-bound (derived from AnyObject). E.g. `let a: Hashable = ...` is not allowed. `Any` is also not allowed.
-- **Not available**: Metatypes, e.g. `let t = SomeClass.Type` or `type(of: value)` are not allowed.
-- **Not available**: Printing and stringification of arbitrary types (achieved via reflection in desktop Swift).
-- **Not available yet (under development)**: Swift Concurrency.
-
-For a more complete list of supported features in Embedded Swift, see [Embedded Swift -- Status](EmbeddedSwiftStatus.md).
-
-## Libraries and modules in Embedded Swift
-
-Traditional library build and use model of Swift is that library code is compiled into a .swiftmodule, containing the interfaces, and a compiled library with binary code, either a .a static library or a .dylib/.so dynamic library. A client's build then uses the .swiftmodule at compile-time, and the static/dynamic library at link-time.
-
-The library model in Embedded Swift works slightly differently: All Swift source code of a library is promoted into being inlineable and visible to client builds (this is necessary for generic code, and beneficial for optimizations for non-generic code), and ends up serialized into the .swiftmodule, the interface of the library. Therefore, the compiled code of a library is never needed, and doesn't even need to be produced. For example:
-
-```bash
-# Build the library, only as a .swiftmomodule. Notice that we never build the .o or .a for the library.
-$ swiftc -target <target> -enable-experimental-feature Embedded -wmo \
-  a.swift b.swift -module-name MyLibrary -emit-module -emit-module-path ./MyLibrary.swiftmodule
-
-# Build the client, "-I ." add the current directory to the module search path list
-$ swiftc -target <target> -enable-experimental-feature Embedded -wmo \
-  client.swift -I . -c -o client.o
-```
-
-The Embedded Swift standard library is distributed in the toolchain the same way: It's strictly a .swiftmodule without any compiled code present anywhere. All the compiling into machine code is performed as part of the client's build. This has the major benefit that the client's build can provide additional ABI and ISA defining flags, such as the above-mentioned `-mfloat-abi`, `-fshort-enums`, `-mcpu`, `-march` flags, and these flags in the client's build will apply to all the library code (including standard library code) as well.
-
-## Allocating and non-allocating Embedded Swift mode
-
-Embedded Swift does allow instantiating and using reference types (classes) which are refcounted objects allocated on the heap. A common case of needing those is for dynamic containers like arrays and sets (they use dynamically-sized heap-allocated class instances as their storage). There is only a handful of Swift language features that cause allocations:
-
-- creating class instances,
-- escaping a closure that captures local variables,
-- creating an indirect enum case with a payload referencing the enum itself
-- explicitly calling allocation APIs (e.g. `UnsafeMutablePointer.allocate()`).
-
-Outside of those cases, Embedded Swift does not perform allocations or cause heap usage.
-
-Some embedded platforms don't have and/or don't want *any heap allocations whatsoever* and don't provide a heap at all. The `-no-allocations` compiler flag can be used to match that, which will cause the compiler to produce an error at compile time when creating class instances or calling allocation APIs.
-
-```bash
-$ cat test.swift
-let p = UnsafeMutablePointer<UInt8>.allocate(capacity: 10)
-$ swiftc test.swift -enable-experimental-feature Embedded -wmo -no-allocations
-test.swift:1:37: error: cannot use allocating operation in -no-allocations mode
-```
-
-## External dependencies
-
-Embedded Swift minimizes external dependencies (i.e. functions that need to be available at link-time), but they still exist. There are generally two categories of dependencies: (1) functions that the Swift standard library or Embedded Swift runtime need to call, and (2) functions/symbols that are implicitly added by LLVM and the compiler pipeline.
-
-For (1), external dependencies are only used based on actual usage of the program under compilation:
-
-- instantiating a class, or using UnsafeMutablePointer.allocate()
-  - dependency: `int posix_memalign(void **, size_t, size_t);`
-  - dependency: `void free(void *);`
-- using print()
-  - dependency: `int putchar(int);`
-- using Hashable, Set, Dictionary, or random-number generating APIs
-  - dependency: `void arc4random_buf(void *, size_t);`
-
-For (2), external dependencies are also triggered by specific code needing them, but they are somewhat lower-level patterns where it might not be obvious that such patterns should cause external dependencies:
-
-- **basic memory copying and zeroing functions**
-  - usage added for a variety of reasons (e.g. using structs on the stack)
-  - dependency: `void *memset(void *, int, size_t);`
-  - dependency: `void *memcpy(void *, const void *, size_t);`
-- **stack protectors** (aka stack cookies or stack canaries)
-  - dependency: `void *__stack_chk_guard;`
-  - dependency: `void __stack_chk_fail(void);`
-  - stack protectors can be disabled with `-disable-stack-protector` swiftc flag
-- **atomics intrinsics**
-  - on CPU architectures that don't have direct load-acquire/store-release support in the ISA, LLVM calls helper functions for atomic operations
-  - needed by refcounting in the Embedded Swift runtime (so any class usage will trigger this dependency)
-  - also needed when using atomics from the Synchronization module
-- **multiplication/division/modulo intrinsics**
-  - on CPU architectures that don't have direct support for the math operations in the ISA
-  - dependency (on Mach-O): `__divti3`
-  - dependency (on Mach-O): `__modti3`
-  - dependency (with EABI): `__aeabi_ldivmod`
-
-The user and/or the platform (via basic libraries like libc or compiler builtins) is expected to provide these well-known APIs.
+Embedded Swift documentation has moved to: [Swift.org](https://docs.swift.org/embedded/documentation/embedded).
diff --git a/docs/Generics/README.md b/docs/Generics/README.md
index 8f51b403315c8..c3eeb3190fd11 100644
--- a/docs/Generics/README.md
+++ b/docs/Generics/README.md
@@ -48,7 +48,7 @@ pdflatex generics
 
 ## Reading the PDF
 
-The book makes use of internal hyperlinks so it is is best to use PDF reader with support for PDF bookmarks and back/forward history:
+The book makes use of internal hyperlinks so it is best to use PDF reader with support for PDF bookmarks and back/forward history:
 
 - Preview.app on macOS fits the bill; you can add Back/Forward buttons to the toolbar with **View** > **Customize Toolbar**.
 - [Skim.app](https://skim-app.sourceforge.io) is a BSD-licensed open source PDF reader for macOS.
diff --git a/docs/Generics/chapters/archetypes.tex b/docs/Generics/chapters/archetypes.tex
index ff8a3f50de3a6..b74d266ecb758 100644
--- a/docs/Generics/chapters/archetypes.tex
+++ b/docs/Generics/chapters/archetypes.tex
@@ -679,7 +679,7 @@ \section{The Archetype Builder}\label{archetype builder}
 This kind of data structure first appeared in the early history of compilers in the implementation of ``\texttt{EQUIV} statements'' for declaring that two symbols ought to share a storage location. These statements thus define an equivalence relation on symbols, and the performance gains from a careful implementation were noted in~\cite{improvedequivalence}. A survey of later techniques appears in~\cite{unionfindsurvey}.
 
 \paragraph{Lazy expansion.}
-From a theoretical point of view, the archetype builder's approach amounts to exhausive enumeration of all \index{derived requiremen!enumerationt}derived requirements and \index{valid type parameter!enumeration}valid type parameters of a generic signature, made slightly more efficient by the choice of data structure (the asymmetry in the handling of member types in \AlgRef{archetype builder merge} means we skip parts of the search space that would yield nothing new).
+From a theoretical point of view, the archetype builder's approach amounts to exhaustive enumeration of all \index{derived requirement!enumeration}derived requirements and \index{valid type parameter!enumeration}valid type parameters of a generic signature, made slightly more efficient by the choice of data structure (the asymmetry in the handling of member types in \AlgRef{archetype builder merge} means we skip parts of the search space that would yield nothing new).
 
 The eager expansion model survived the introduction of protocol \texttt{where} clauses in Swift~4 \cite{se0142}, and thus associated requirements, with only relatively minor changes. The introduction of recursive conformances in Swift~4.1~\cite{se0157} necessitated a larger overhaul. Once the type parameter graph becomes infinite, the eager conformance requirement expansion of \AlgRef{archetype builder expand} no longer makes sense. The \texttt{ArchetypeBuilder} was renamed to the \IndexDefinition{GenericSignatureBuilder@\texttt{GenericSignatureBuilder}}\texttt{GenericSignatureBuilder} as part of a re-design where the recursive expansion was now performed as needed, within the lookup of \AlgRef{archetype builder lookup} itself \cite{implrecursive}.
 
diff --git a/docs/Generics/chapters/building-generic-signatures.tex b/docs/Generics/chapters/building-generic-signatures.tex
index 500e43e15f2e0..77aa48ca5db30 100644
--- a/docs/Generics/chapters/building-generic-signatures.tex
+++ b/docs/Generics/chapters/building-generic-signatures.tex
@@ -768,7 +768,7 @@ \section{Well-Formed Requirements}\label{generic signature validity}
 \ReflexStep{2}{\rT.Indices}{3}
 \end{gather*}
 
-We now state the general result. We need this for the proof of \ThmRef{valid theorem}, and also later in \SecRef{conformance paths exist}, when we show that every derived conformance requirement has a derivation of a certrain form.
+We now state the general result. We need this for the proof of \ThmRef{valid theorem}, and also later in \SecRef{conformance paths exist}, when we show that every derived conformance requirement has a derivation of a certain form.
 
 \begin{lemma}[Formal substitution]\label{subst lemma}
 Let $G$ be an arbitrary generic signature. Suppose that $G\vdash\tT$ and $G\vdash\TP$ for some type parameter \tT\ and protocol \tP. Then if we take a valid type parameter or derived requirement of~$\GP$ and replace \tSelf\ with \tT\ throughout, we get a valid type parameter or derived requirement of~$G$, just rooted in \tT. That is:
@@ -1312,7 +1312,7 @@ \section{Requirement Minimization}\label{minimal requirements}
 We now state the general definition.
 
 \begin{definition}\label{conflicting req def}
-Let $G$ be a \index{well-formed generic signature}well-formed generic signature. If $G$ has a pair of \index{derived requirement!conflicts}derived requirements $R_1$~and~$R_2$ where $R_1\otimes\Sigma$ and $R_2\otimes\Sigma$ cannot both be \index{satisfied requirement!conflicts}satisfied by the same substitution map~$\Sigma$, then $R_1$~and~$R_2$ define a pair of \IndexDefinition{conflicting requirement}\emph{confliciting requirements}. A generic signature $G$ is \emph{conflict-free} if it does not have any pairs of conflicting requirements. The pairs of derived requirements that can lead to conflicts are enumerated below:
+Let $G$ be a \index{well-formed generic signature}well-formed generic signature. If $G$ has a pair of \index{derived requirement!conflicts}derived requirements $R_1$~and~$R_2$ where $R_1\otimes\Sigma$ and $R_2\otimes\Sigma$ cannot both be \index{satisfied requirement!conflicts}satisfied by the same substitution map~$\Sigma$, then $R_1$~and~$R_2$ define a pair of \IndexDefinition{conflicting requirement}\emph{conflicting requirements}. A generic signature $G$ is \emph{conflict-free} if it does not have any pairs of conflicting requirements. The pairs of derived requirements that can lead to conflicts are enumerated below:
 \begin{enumerate}
 \item For two concrete \index{same-type requirement!conflicts}same-type requirements $\SameReq{T}{$\tX_1$}$ and $\SameReq{T}{$\tX_2$}$, we desugar the ``combined'' requirement $\SameReq{$\tX_1$}{$\tX_2$}$, as we already saw. Here and every remaining case below, desugaring will either detect a conflict, or produce a simpler list of requirements that can replace one of the two original requirements.
 \item For a concrete same-type requirement $\TX$ and superclass requirement $\TC$, we desugar $\ConfReq{X}{C}$, which can be satisfied only if~\tX\ is a class type that is also a subclass of~\tC.
diff --git a/docs/Generics/chapters/completion.tex b/docs/Generics/chapters/completion.tex
index e08adf790db4b..f0a77ef02e3f4 100644
--- a/docs/Generics/chapters/completion.tex
+++ b/docs/Generics/chapters/completion.tex
@@ -387,7 +387,7 @@ \chapter{Completion}\label{completion}
 \end{enumerate}
 \end{algorithm}
 
-We can now describe the main loop of the Knuth-Bendix completion procedure, which repeatedly finds and resolves critical pairs until no more non-trivial critical pairs remain. This process might not terminate, and we might find ourselves discovering new critical pairs and adding new rules to resolve them, forever. To prevent an infinite loop in the case of failure, we implement a termination check; if we think we've done too much work already, we give up on constructing a covergent rewriting system. We already mentioned the \textbf{left-simplified}, \textbf{right-simplified}, and \textbf{substitution-simplified} flags a few times; they are set by the rule simplification passes, with the first two described in \SecRef{rule reduction} and the third one in \SecRef{subst simplification}. These passes are invoked at appropriate times in the main loop below.
+We can now describe the main loop of the Knuth-Bendix completion procedure, which repeatedly finds and resolves critical pairs until no more non-trivial critical pairs remain. This process might not terminate, and we might find ourselves discovering new critical pairs and adding new rules to resolve them, forever. To prevent an infinite loop in the case of failure, we implement a termination check; if we think we've done too much work already, we give up on constructing a convergent rewriting system. We already mentioned the \textbf{left-simplified}, \textbf{right-simplified}, and \textbf{substitution-simplified} flags a few times; they are set by the rule simplification passes, with the first two described in \SecRef{rule reduction} and the third one in \SecRef{subst simplification}. These passes are invoked at appropriate times in the main loop below.
 
 \begin{algorithm}[Knuth-Bendix completion procedure]\label{knuthbendix} Takes a list of rewrite rules as input. Records new rewrite rules, as well as rewrite loops, and returns success or failure. On success, the rewrite rules define a convergent rewriting system. Failure indicates we got a non-orientable rewrite rule, or we triggered the termination check.
 \begin{enumerate}
@@ -1233,7 +1233,7 @@ \section{More Critical Pairs}\label{more critical pairs}
 {\assocsym{S}{C}\cdot(\ProtoConfInv{\assocsym{S}{C}}{S})}
 \end{center}
 
-If the identity conformance rule had not been part of that initial set, this last critical pair would \emph{define} the identity conformance rule, and we would obtain the same rewrite system in the end. We don't need to explicitly add the identity conformance rule, after all. There is a practical consideration though. By making this rule part of the initial set, and cruicially, marking it \index{permanent rule}\textbf{permanent}, we remove it from consideration in the rewrite system minimization algorithm. This cuts out a lot of unnecessary work.
+If the identity conformance rule had not been part of that initial set, this last critical pair would \emph{define} the identity conformance rule, and we would obtain the same rewrite system in the end. We don't need to explicitly add the identity conformance rule, after all. There is a practical consideration though. By making this rule part of the initial set, and crucially, marking it \index{permanent rule}\textbf{permanent}, we remove it from consideration in the rewrite system minimization algorithm. This cuts out a lot of unnecessary work.
 
 \smallskip
 
@@ -1523,7 +1523,7 @@ \section{Recursive Conformances}\label{recursive conformances redux}
 \end{tabular}
 \end{center}
 
-\ListingRef{rewrite system q} shows the convegent rewrite system for \tQ, which imports rules from protocol~\texttt{N}. Completion discovers the following critical pairs; we will be content to just summarize because they are similar to previous examples:
+\ListingRef{rewrite system q} shows the convergent rewrite system for \tQ, which imports rules from protocol~\texttt{N}. Completion discovers the following critical pairs; we will be content to just summarize because they are similar to previous examples:
 \begin{itemize}
 \item Rule (6) overlaps with (7) on $\pQ\cdot\pQ\cdot\nA$. We define rule (\CRule{10}) (this general principle was established in \ExRef{proto assoc rule}).
 \item Rule (8) overlaps with (2) on $\pQ\cdot\protosym{N}\cdot\nA$. We define rule (\CRule{11}) (\ExRef{protocol inheritance completion example}).
diff --git a/docs/Generics/chapters/conformance-paths.tex b/docs/Generics/chapters/conformance-paths.tex
index c5fa113c31c6a..a6711284e8f9d 100644
--- a/docs/Generics/chapters/conformance-paths.tex
+++ b/docs/Generics/chapters/conformance-paths.tex
@@ -143,7 +143,7 @@ \chapter{Conformance Paths}\label{conformance paths}
 \qquad {} = \Proto{Sequence} \otimes \texttt{Substring}\\
 \qquad {} = \SubstringSequence
 \end{gather*}
-However, we wish to recover $\SubstringSequence$ from $\Sigma$ alone, without resorting to a \index{global conformance lookup}\emph{global} conformance lookup, as we did in the above calculation. We don't have a lot of options. In fact, pretty much the \emph{only} thing local confomance lookup can do is take one of the \index{root conformance}root conformances stored in the substitution map, and proceed to apply \index{associated conformance projection}associated conformance projection operations.
+However, we wish to recover $\SubstringSequence$ from $\Sigma$ alone, without resorting to a \index{global conformance lookup}\emph{global} conformance lookup, as we did in the above calculation. We don't have a lot of options. In fact, pretty much the \emph{only} thing local conformance lookup can do is take one of the \index{root conformance}root conformances stored in the substitution map, and proceed to apply \index{associated conformance projection}associated conformance projection operations.
 
 Our generic signature $G$ only has one explicit conformance requirement, so we start with the lone root conformance of $\Sigma$:
 \[
diff --git a/docs/Generics/chapters/conformances.tex b/docs/Generics/chapters/conformances.tex
index d92bcd36e8977..8a015716b03e5 100644
--- a/docs/Generics/chapters/conformances.tex
+++ b/docs/Generics/chapters/conformances.tex
@@ -64,7 +64,7 @@ \chapter{Conformances}\label{conformances}
 \draw [arrow] (SquareShape) -- (Square);
 \end{tikzpicture}
 \end{center}
-We denote this inherited conformance by $\ConfReq{Square}{Shape}$. It behaves identically to the superclass conformance $\ConfReq{Polygon}{Shape}$, except if ask for its \index{conforming type!inherited conformance}conforming type, we get back \texttt{Square} instead of \texttt{Polygon}. In \ExRef{inherited specialized conf}, we will see that more complex behavors can manifest when the superclass declaration has generic parameters.
+We denote this inherited conformance by $\ConfReq{Square}{Shape}$. It behaves identically to the superclass conformance $\ConfReq{Polygon}{Shape}$, except if ask for its \index{conforming type!inherited conformance}conforming type, we get back \texttt{Square} instead of \texttt{Polygon}. In \ExRef{inherited specialized conf}, we will see that more complex behaviors can manifest when the superclass declaration has generic parameters.
 
 \section{Conformance Lookup}\label{conformance lookup}
 
@@ -320,7 +320,7 @@ \section{Type Witnesses}\label{type witnesses}
   func play(_: String) {}
 }
 \end{Verbatim}
-Associated type inference \index{synthesized declaration}synthesizes a type alias member for each inferred associated type, so we can refer to \texttt{Cat.Toy} elsewhere in the program, as if we explictly declared the type alias \texttt{Toy} as a member of \texttt{Cat}. Now, consider \texttt{Dog}, which witnesses \texttt{Pet}'s associated type with a generic parameter named \texttt{Toy}. This is Case~3:
+Associated type inference \index{synthesized declaration}synthesizes a type alias member for each inferred associated type, so we can refer to \texttt{Cat.Toy} elsewhere in the program, as if we explicitly declared the type alias \texttt{Toy} as a member of \texttt{Cat}. Now, consider \texttt{Dog}, which witnesses \texttt{Pet}'s associated type with a generic parameter named \texttt{Toy}. This is Case~3:
 \begin{Verbatim}
 struct Dog<Toy>: Pet {
   // synthesized: typealias Toy = Toy
diff --git a/docs/Generics/chapters/existential-types.tex b/docs/Generics/chapters/existential-types.tex
index 8e3bc68344752..1b22ce698383e 100644
--- a/docs/Generics/chapters/existential-types.tex
+++ b/docs/Generics/chapters/existential-types.tex
@@ -106,7 +106,7 @@
 Recall from \ChapRef{genericenv} that there are three kinds of generic environments. We've seen primary generic environments, which are associated with generic declarations. We also saw opaque generic environments, which are instantiated from an opaque return declaration and substitution map, in \SecRef{opaquearchetype}. Now, it's time to introduce the third kind, the opened generic environment. An opened generic environment is created from an opened existential signature of the first kind (with no parent generic signature). The archetypes of an opened generic environment are \emph{opened archetypes}.
 
 \index{call expression}
-When the expression type checker encounters a call expression where an argument of existential type is passed to a parameter of generic parameter type, the existential value is \emph{opened}, projecting the value and assigning it a new opened archetype from a fresh opened generic environment. The call expression is rewritten by wrapping the entire call is wrapped in an \texttt{OpenExistentialExpr}, which stores two sub-expressions. The first sub-expression is the original call argument, which evaluates to the value of existential type. The payload value and opened archetype is scoped to the second sub-expression, which consumes the payload value. The call argument is replaced with a \texttt{OpaqueValueExpr}, which has the opened archetype type. The opened archetype also becomes the replacement type for the generic parameter in the call's substitution map.
+When the expression type checker encounters a call expression where an argument of existential type is passed to a parameter of generic parameter type, the existential value is \emph{opened}, projecting the value and assigning it a new opened archetype from a fresh opened generic environment. The call expression is rewritten by wrapping the entire call in an \texttt{OpenExistentialExpr}, which stores two sub-expressions. The first sub-expression is the original call argument, which evaluates to the value of existential type. The payload value and opened archetype is scoped to the second sub-expression, which consumes the payload value. The call argument is replaced with a \texttt{OpaqueValueExpr}, which has the opened archetype type. The opened archetype also becomes the replacement type for the generic parameter in the call's substitution map.
 
 For example, if \texttt{animal} is a value of type \texttt{any Animal}, the expression \texttt{animal.eat()} calling a protocol method looks like this before opening:
 \begin{quote}
@@ -463,8 +463,8 @@
 
 func careForAnimals(_ animals: [any Animal]) {
   for animal in animals {
-    careForAnimal(animal)  // existential opened here in Swift 5.7;
-                           // type check error in Swift 5.6.
+    petAnimal(animal)  // existential opened here in Swift 5.7;
+                       // type check error in Swift 5.6.
   }
 }
 \end{Verbatim}
diff --git a/docs/Generics/generics.tex b/docs/Generics/generics.tex
index 4522c28b93df3..1c6fe88834fe9 100644
--- a/docs/Generics/generics.tex
+++ b/docs/Generics/generics.tex
@@ -241,7 +241,7 @@
          \\*(Cited on pages #2.)%
 \fi }
 
-% Request evalator requests
+% Request evaluator requests
 \newcommand{\Request}[1]{\textbf{#1}}
 
 % Generic parameters
diff --git a/docs/HowToGuides/GettingStarted.md b/docs/HowToGuides/GettingStarted.md
index 79cf5f20ab090..1de0dcf0eb249 100644
--- a/docs/HowToGuides/GettingStarted.md
+++ b/docs/HowToGuides/GettingStarted.md
@@ -142,10 +142,10 @@ toolchain as a one-off, there are a couple of differences:
 1. Install Xcode. The minimum required version is specified in the node
    information on <https://ci.swift.org>, may change frequently, and is often
    a beta release.
-1. Install [CMake][], [Ninja][] and [Sccache][]:
+1. Install [Ninja][] and [Sccache][]:
    - Via [Homebrew][] (recommended):
      ```sh
-     brew install cmake ninja sccache
+     brew install ninja sccache
      ```
    - Via [Homebrew Bundle][]:
      ```sh
@@ -153,7 +153,6 @@ toolchain as a one-off, there are a couple of differences:
      ```
 
 [Xcode]: https://developer.apple.com/xcode/resources/
-[CMake]: https://cmake.org
 [Ninja]: https://ninja-build.org
 [Homebrew]: https://brew.sh/
 [Homebrew Bundle]: https://github.com/Homebrew/homebrew-bundle
@@ -164,6 +163,7 @@ toolchain as a one-off, there are a couple of differences:
    * [Ubuntu 18.04](https://github.com/swiftlang/swift-docker/blob/main/swift-ci/main/ubuntu/18.04/Dockerfile)
    * [Ubuntu 20.04](https://github.com/swiftlang/swift-docker/blob/main/swift-ci/main/ubuntu/20.04/Dockerfile)
    * [Ubuntu 22.04](https://github.com/swiftlang/swift-docker/blob/main/swift-ci/main/ubuntu/22.04/Dockerfile)
+   * [Ubuntu 24.04](https://github.com/swiftlang/swift-docker/blob/main/swift-ci/main/ubuntu/24.04/Dockerfile)
    * [CentOS 7](https://github.com/swiftlang/swift-docker/blob/main/swift-ci/main/centos/7/Dockerfile)
    * [Amazon Linux 2](https://github.com/swiftlang/swift-docker/blob/main/swift-ci/main/amazon-linux/2/Dockerfile)
 
@@ -199,7 +199,6 @@ toolchain as a one-off, there are a couple of differences:
 
 ### Spot check dependencies
 
-* Run `cmake --version`; this should be at least 3.19.6 (3.24.2 if you want to use Xcode for editing on macOS).
 * Run `python3 --version`; this should be at least 3.6.
 * Run `ninja --version`; check that this succeeds.
 * If you installed and want to use Sccache: Run `sccache --version`; check
diff --git a/docs/LibraryEvolution.rst b/docs/LibraryEvolution.rst
index 50505ef7bb1d1..ff79d1702c8b5 100644
--- a/docs/LibraryEvolution.rst
+++ b/docs/LibraryEvolution.rst
@@ -365,8 +365,7 @@ the following changes are permitted:
   an existing property (unless the struct is marked ``@frozen``; see below).
   This is effectively the same as modifying the body of a setter.
 - Removing any non-ABI-public members, including stored properties.
-- Adding a conformance to an ABI-public protocol *that was introduced in the
-  same release* (see below).
+- Adding a conformance to an ABI-public protocol (see below about availability).
 - Adding or removing a conformance to a non-ABI-public protocol.
 - Adding ``@dynamicCallable`` to the struct.
 
@@ -382,17 +381,9 @@ target for the library is an error.
 It is not safe to add or remove ``mutating`` or ``nonmutating`` from a member
 or accessor within a struct.
 
-If a conformance is added to a type in version 1.1 of a library, it's important
-that it isn't accessed in version 1.0. This means that it is only safe to add
-new conformances to ABI-public protocols when the protocol is introduced, and
-not after. If the protocol comes from a separate module, there is no safe way
-to conform to it.
-
-.. admonition:: TODO
-
-    Coming up with a way to do this, either with availability annotations for
-    protocol conformances or a way to emit a fallback copy of the conformance
-    for clients on older library versions to use, is highly desired.
+When introducing a new conformance of an existing type to an existing protocol,
+it is important to annotate the conformance with availability. This is achieved
+by declaring the conformance on an extension and annotating the extension.
 
 
 Methods and Initializers
diff --git a/docs/ReferenceGuides/LifetimeAnnotation.md b/docs/ReferenceGuides/LifetimeAnnotation.md
new file mode 100644
index 0000000000000..5e399d268b8e3
--- /dev/null
+++ b/docs/ReferenceGuides/LifetimeAnnotation.md
@@ -0,0 +1,184 @@
+# @_lifetime annotation
+
+## Introduction
+
+`@_lifetime` annotations are now available under `-enable-experimental-features Lifetimes`. The feature proposal is documented in [PR: Lifetime dependencies #2750](https://github.com/swiftlang/swift-evolution/pull/2750).
+
+To summarize the basic syntax: functions require a `@_lifetime` annotation when they return a non-Escapable type, either as the function result, or as an `inout` parameter. The annotation syntax pattern is `@_lifetime(target: <scope> source)` where `target` is a function output and `source` is an input. If `target:` is omitted, then it is assumed to be the function's result.
+
+`<scope> ::= [borrow|&|copy]`
+
+`borrow` creates a new borrow scope that guarantees exclusive read access to the caller's `source` argument over all uses of `target`.
+
+`&` creates a new borrow scope that guarantees exclusive write access to the caller's `source` argument over all uses of `target`.
+
+`copy` copies the lifetime constraints on the caller's `source` argument to `target`.
+
+The `@lifetime` annotation is enforced both in the body of the function and at each call site. For both `borrow` and `&` scoped dependencies, the function's implementation guarantees that `target` is valid as long as `source` is alive, and each caller of the function guarantees that `source` will outlive `target`. For `copy` dependencies, the function's implementation guarantees that all constraints on `target` are copied from `source`, and the caller propagates all lifetime constraints on `source` to all uses of `target`.
+
+## Default lifetimes
+
+The Swift 6.2 compiler provided default `@_lifetime` behavior whenever it can do so without ambiguity. Often, despite ambiguity, an "obvious" default exists, but we wanted to introduce defaults slowly after developers have enough experience to inform discussion about them. This document tracks the current state of the implementation as it progresses from the original 6.2 implementation. Corresponding tests are in `test/Sema/lifetime_depend_infer.swift`; searching for "DEFAULT:" highlights the rules defined below...
+
+### Single parameter default rule
+
+Given a function or method that returns a non-Escapable result:
+
+- Default to `@_lifetime(<scope> a)` for a `~Escapable` result on functions with a single parameter `a`.
+
+- Default to `@_lifetime(<scope> self)` for a `~Escapable` result on methods with no parameters.
+
+| Type of parameter | default                        |
+| (`a` or `self`)   | lifetime dependency            |
+| ----------------- | ------------------------------ |
+| `Escapable`       | `@_lifetime(borrow param)`[^1] |
+| `inout Escapable` | `@_lifetime(&param)`[^1]       |
+| `~Escapable`      | none[^2]                       |
+
+[^1]: When the parameter is `BitwiseCopyable`, such as an integer or unsafe pointer, the single parameter default rule applies to function parameters but not to the implicit `self` parameter. Depending on a `BitwiseCopyable` value is a convenience for APIs that construct span-like values from an `UnsafePointer` passed as an argument. This creates a dependency on a local copy of the pointer variable with subtle semantics. User-defined `BitwiseCopyable` structs should generally avoid such subtle lifetime dependencies. If needed, the author of the data type should explicitly opt into them.
+
+[^2]: When the single parameter is also `~Escapable`, the result must depend on it, but the dependency may either be scoped (`borrow` or `&`) or it may be copied (`copy`). `copy` is the obvious choice when the parameter and result are the same type, but it is not always correct. Furthermore, a lifetime dependency can only be copied from a generic type when result as the same generic type. This case is therefore handled by same-type default lifetime (discussed below) rather than as a default `@_lifetime` rule.
+
+Examples:
+
+```swift
+struct A: Escapable {
+  let obj: AnyObject // ~BitwiseCopyable
+}
+struct NE: ~Escapable {...}
+
+/* DEFAULT: @_lifetime(borrow a) */
+func oneParam_NEResult(a: A) -> NE
+
+/* DEFAULT: @_lifetime(&a) */
+func oneInoutParam_NEResult(a: inout A) -> NE
+
+extension A /* Self: Escapable */ {
+  /* DEFAULT: @_lifetime(borrow self) */
+  func noParam_NEResult() -> NE
+
+  /* DEFAULT: @_lifetime(&self) */
+  mutating func mutating_noParam_NEResult() -> NE
+}
+```
+
+### Implicit initializer and setter defaults
+
+An implicit setter of a `~Escapable` stored property defaults to `@_lifetime(self: copy self, copy newValue)`. This is always correct because the setter simply assigns the stored property to the newValue. Assigning a `~Escapable` variable copies the lifetime dependency.
+
+Similarly, an implicit initializer of a non-Escapable struct defaults to `@_lifetime(self: copy arg)` if all of the initializer arguments are `~Escapable`. This is equivalent to assigning each `~Escapable` stored property. If, however, any initializer arguments are `Escapable`, then no default lifetime is provided unless it is the sole argument, in which case the single parameter rule applies.
+
+### `inout` parameter default rule
+
+- Default to `@_lifetime(a: copy a)` for all `inout` parameters where `a` is  `~Escapable`.
+
+- Default to `@_lifetime(self: copy self)` on `mutating` methods where `self` is `~Escapable`.
+
+#### Examples
+
+```swift
+struct A: Escapable {
+  let obj: AnyObject // ~BitwiseCopyable
+}
+struct NE: ~Escapable {...}
+
+/* DEFAULT: @_lifetime(a: copy a) */
+func inoutNEParam_void(_: inout NE) -> ()
+
+/* DEFAULT: @_lifetime(a: copy a) */
+/* DEFAULT: @_lifetime(b: copy b) */
+func inoutNEParam_inoutNEParam_void(a: inout NE, b: inout NE) -> ()
+
+/* DEFAULT: @_lifetime(ne: copy ne) */
+@_lifetime(&ne)
+func inoutNEParam_NEResult(ne: inout NE) -> NE
+
+extension A /* Self: Escapable */ {
+  /* DEFAULT: @_lifetime(ne: copy NE) */
+  func inoutNEParam_void(a: inout ) -> ()
+
+  /* DEFAULT: @_lifetime(ne: copy NE) */
+  mutating func mutating_inoutNEParam_void() -> ()
+
+  /* DEFAULT: @_lifetime(ne: copy NE) */
+  @_lifetime(&self)
+  func inoutNEParam_NEResult(ne: inout NE) -> NE
+}
+
+extension NE /* Self: ~Escapable */ {
+  /* DEFAULT: @_lifetime(self: copy self) */
+  mutating func mutating_noParam_void() -> ()
+
+  /* DEFAULT: @_lifetime(self: copy self) */
+  mutating func mutating_oneParam_void(_: NE) -> ()
+
+  /* DEFAULT: @_lifetime(self: copy self) */
+  /* DEFAULT: @_lifetime(ne: copy ne) */
+  mutating func mutating_inoutParam_void(ne: inout NE) -> ()
+
+  /* DEFAULT: @_lifetime(self: copy self) */
+  @_lifetime(&self)
+  mutating func mutating_noParam_NEResult() -> NE
+}
+```
+
+## Same-type default lifetime (unimplemented)
+
+Given a function declaration:
+
+`func foo(..., a: A, ...) -> R { ... }`
+
+Where `R: ~Escapable` and `A == R`, default to `@_lifetime(copy a)`.
+For methods, the same rule applies to implicit `Self` parameter.
+
+This handles the obvious cases in which both the parameter and result are `~Escapable`. For example:
+
+```swift
+extension Span {
+  /* DEFAULT: @_lifetime(copy self) */
+  func extracting(droppingLast k: Int) -> Self { ... }
+}
+```
+
+### Generic same-type default lifetime (unimplemented)
+
+The same-type default lifetime rule described above is convenient for nominal types but essential for generic type parameters.
+
+Given a generic function declaration:
+
+`func foo<A, R>(..., a: A, ...) -> R { ... }`
+
+The same-type default lifetime rule applies to the types in the function declaration's generic context just as it did for nominal types in the previous example. So, again, if type resolution determines `R: ~Escapable` and `A == R`, then `@_lifetime(copy a)` will be default.
+
+Unlike nominal types, the programmer is not allowed to explicitly declare a lifetime dependency, `@_lifetime(copy
+a)`, unless the argument and result types are equivalent (`A == R`). Copying a lifetime dependency from one value to another requires that both values are non-Escapable. Generic types are conditionally non-Escapable (their lifetime dependencies are type-erased), so type equivalence is the only way to ensure that both values are non-Escapable under the same conditions.
+
+Here we see how same-type lifetime requirement applies to type substitution and associated types:
+
+```swift
+protocol P {
+  associatedtype T: ~Escapable
+}
+
+protocol Q {
+  associatedtype U: ~Escapable
+}
+
+struct S<A: P, B: Q> {
+  /* OK: @_lifetime(copy a) is valid and default */
+  func foo(a: A.T) -> B.U where A.T == B.U
+}
+```
+
+Note that lifetime dependencies are resolved at function declaration time, which determines the function's type. The generic context at the point of function invocation is not considered. For example, the following declaration of `foo` is invalid, because it's argument and results types don't match at the point of declaraion, even though the argument and result do have the same type when invoked inside `bar`:
+
+```swift
+struct S<T: ~Escapable, U: ~Escapable> {
+  static func foo(a: T) -> U // ERROR: missing lifetime dependency
+}
+
+/* OK: @_lifetime(copy a) is valid and default */
+func bar<T: ~Escapable>(a: T) -> T {
+  S<T, T>.foo(a: a) // The same-type rule is satisfied in this context, but 'foo's declaration is invalid.
+}
+```
diff --git a/docs/ReferenceGuides/UnderscoredAttributes.md b/docs/ReferenceGuides/UnderscoredAttributes.md
index 07d66bc5013b9..a9db7c7ea998e 100644
--- a/docs/ReferenceGuides/UnderscoredAttributes.md
+++ b/docs/ReferenceGuides/UnderscoredAttributes.md
@@ -600,6 +600,43 @@ inherit the actor context (i.e. what actor it should be run on) based on the
 declaration site of the closure rather than be non-Sendable. This does not do
 anything if the closure is synchronous.
 
+This works with global actors as expected:
+
+```swift 
+@MainActor
+func test() {
+  Task { /* main actor isolated */ }
+}
+```
+
+However, for the inference to work with instance actors (i.e. `isolated` parameters),
+the closure must capture the isolated parameter explicitly:
+
+```swift 
+func test(actor: isolated (any Actor)) {
+  Task { /* non isolated */ } // !!!
+}
+
+func test(actor: isolated (any Actor)) {
+  Task { // @_inheritActorContext
+    _ = actor // 'actor'-isolated 
+  }
+}
+```
+
+The attribute takes an optional modifier '`always`', which changes this behavior 
+and *always* captures the enclosing isolated context, rather than forcing developers
+to perform the explicit capture themselfes:
+
+```swift
+func test(actor: isolated (any Actor)) {
+  Task.immediate { // @_inheritActorContext(always)
+    // 'actor'-isolated!
+    // (without having to capture 'actor explicitly')
+  }
+}
+```
+
 DISCUSSION: The reason why this does nothing when the closure is synchronous is
 since it does not have the ability to hop to the appropriate executor before it
 is run, so we may create concurrency errors.
diff --git a/docs/RequestEvaluator.md b/docs/RequestEvaluator.md
index 01e09b4309294..e1ce190e9bbfb 100644
--- a/docs/RequestEvaluator.md
+++ b/docs/RequestEvaluator.md
@@ -66,9 +66,8 @@ To define a request as a dependency source, it must implement an accessor for th
 
 ## Open Projects
 
-The request-evaluator is relatively new to the Swift compiler, having been introduced in mid-2018. There are a number of improvements that can be made to the evaluator itself and how it is used in the compiler:
+There are a number of improvements that can be made to the evaluator itself and how it is used in the compiler:
 
-* The evaluator uses a `DenseMap<AnyRequest, AnyValue>` as its cache: we can almost certainly do better with per-request-kind caches that don't depend on so much type erasure.
 * Explore how best to cache data structures in the evaluator. For example, caching `std::vector<T>` or `std::string` implies that we'll make copies of the underlying data structure each time we access the data. Could we automatically intern the data into an allocation arena owned by the evaluator, and vend `ArrayRef<T>` and `StringRef` to clients instead?
 * Cycle diagnostics are far too complicated and produce very poor results. Consider replacing the current `diagnoseCycle`/`noteCycleStep` scheme with a single method that produces summary information (e.g., a short summary string + source location information) and provides richer diagnostics from that string.
 * The `isCached()` check to determine whether a specific instance of a request is worth caching may be at the wrong level, because one generally has to duplicate effort (or worse, code!) to make the decision in `isCached()`. Consider whether the `evaluator()` function could return something special to say "produce this value without caching" vs. the normal "produce this value with caching".
diff --git a/docs/SIL/Instructions.md b/docs/SIL/Instructions.md
index 9f9691b964f59..e4bbe28a3b072 100644
--- a/docs/SIL/Instructions.md
+++ b/docs/SIL/Instructions.md
@@ -832,7 +832,7 @@ load-ownership-kind ::= 'take'
 ```
 
 Loads the value at address `%0` from memory. `T` must be a loadable
-type. This does not affect the reference count, if any, of the loaded
+type. An unqualified load does not affect the reference count, if any, of the loaded
 value; the value must be retained explicitly if necessary. It is
 undefined behavior to load from uninitialized memory or to load from an
 address that points to deallocated storage.
@@ -840,8 +840,8 @@ address that points to deallocated storage.
 In OSSA the ownership kind specifies how to handle ownership:
 -  **trivial**: the loaded value is trivial and no further action must be taken
                 than to load the raw bits of the value
--  **copy**: the loaded value is copied and the original value stays in the
-             memory location.
+-  **copy**: the loaded value is copied (e.g., retained) and the original value
+                stays in the memory location.
 -  **take**: the value is _moved_ from the memory location without copying.
              After the `load`, the memory location remains uninitialized.
 
@@ -1032,7 +1032,7 @@ extend_lifetime %0 : $X
 ```
 
 Indicates that a value's linear lifetime extends to this point.
-Inserted by OSSALifetimeCompletion(AvailabilityBoundary) in order to
+Inserted by OSSACompleteLifetime(AvailabilityBoundary) in order to
 provide the invariant that a value is either consumed OR has an
 `extend_lifetime` user on all paths and furthermore that all
 uses are within the boundary defined by that set of instructions (the
@@ -1064,43 +1064,49 @@ a sequence that also correctly destroys the current value.
 This instruction is only valid in Raw SIL and is rewritten as
 appropriate by the definitive initialization pass.
 
-### assign_by_wrapper
+### assign_or_init 
 
 ```
-sil-instruction ::= 'assign_by_wrapper' sil-operand 'to' mode? sil-operand ',' 'init' sil-operand ',' 'set' sil-operand
+sil-instruction ::= 'assign_or_init' mode? attached-property ',' self-or-local ',' sil-operand ',' 'value' ',' sil-operand ',' 'init' sil-operand ',' 'set' sil-operand
 
-mode ::= '[init]' | '[assign]' | '[assign_wrapped_value]'
+mode ::= '[init]' | '[assign]'
+attached-property ::= '#' sil-decl-ref
+self-or-local ::= 'self' | 'local'
 
-assign_by_wrapper %0 : $S to %1 : $*T, init %2 : $F, set %3 : $G
-// $S can be a value or address type
-// $T must be the type of a property wrapper.
-// $F must be a function type, taking $S as a single argument (or multiple arguments in case of a tuple) and returning $T
-// $G must be a function type, taking $S as a single argument (or multiple arguments in case of a tuple) and without a return value
+// Nominal Context:
+assign_or_init #MyStruct.x, self %A, value %V, init %I, set %S
+// Local Context (only emitted with compiler synthesized thunks currently):   
+assign_or_init #x, local %L, value %V, init %I, set %S
 ```
 
-Similar to the [assign](#assign) instruction, but the assignment is done
-via a delegate.
+Assigns or initializes a computed property with an attached init accessor. 
+This instruction is emitted during SILGen without an explicit mode. 
+The definitive initialization (DI) pass resolves the mode and rewrites
+the instruction accordingly:
 
-Initially the instruction is created with no mode. Once the mode is
-decided (by the definitive initialization pass), the instruction is
-lowered as follows:
+- `[init]`: In this mode, the init accessor `%I` is called with `%V` 
+as an argument. 
+- `[assign]`: In this mode, the setter function `%S` is called with `%V`
+as an argument.
 
-If the mode is `initialization`, the function `%2` is called with `%0`
-as argument. The result is stored to `%1`. In case of an address type,
-`%1` is simply passed as a first out-argument to `%2`.
+This instruction is only valid in Raw SIL and is rewritten as appropriate by
+the DI pass.
 
-The `assign` mode works similar to `initialization`, except that the
-destination is "assigned" rather than "initialized". This means that
-the existing value in the destination is destroyed before the new value
-is stored.
-
-If the mode is `assign_wrapped_value`, the function `%3` is called with
-`%0` as argument. As `%3` is a setter (e.g. for the property in the
-containing nominal type), the destination address `%1` is not used in
-this case.
-
-This instruction is only valid in Raw SIL and is rewritten as
-appropriate by the definitive initialization pass.
+Operand Roles:
+- `attached-property`: The property being written to. For nominal contexts, this 
+refers to a property with an attached init accessor (e.g. `#MyStruct.x`). For local 
+contexts, it refers to a local variable name (e.g. `#x`).
+- `self-or-local`: 
+  - `self %A`: Refers to the instance of the type that owns the property with the 
+  attached init accessor.
+  - `local %L`: Indicates the assignment is to a local variable (`%L`) rather than 
+  a property of a nominal type. While init accessors are not currently available to be 
+  used in local contexts in user-authored code, the compiler can synthesize an `assign_or_init`
+  in local contexts using an init accessor thunk in special cases.
+- `value %V`: The input value passed to either the `init` or `set` function, depending on 
+the selected DI mode.
+- `init %I`: A partially applied function implementing the property's init accessor.
+- `set %S`: A partially applied function implementing the property's setter.
 
 ### mark_uninitialized
 
@@ -2146,6 +2152,22 @@ not replace this reference with a not uniquely reference object.
 
 For details see [Copy-on-Write Representation](SIL.md#Copy-on-Write-Representation).
 
+### end_cow_mutation_addr
+
+```
+sil-instruction ::= 'end_cow_mutation_addr' sil-operand
+
+end_cow_mutation_addr %0 : $*T
+// %0 must be of an address $*T type
+```
+
+This instruction marks the end of mutation of an address. The address could be
+an opaque archetype, a struct, tuple or enum type and the end_cow_mutation_addr
+will apply to all members contained within it.
+It is currently only generated in cases where we maybe deriving a MutableSpan from
+`%0` since it is not possible to schedule an `end_cow_mutation` in the standard
+library automatically for Array.mutableSpan etc.
+
 ### destroy_not_escaped_closure
 
 ```
@@ -2599,11 +2621,11 @@ except:
     instead of its normal results.
 
 The final (in the case of `@yield_once`) or penultimate (in the case of
-`@yield_once_2`) result of a `begin_apply` is a "token", a special
-value which can only be used as the operand of an `end_apply` or
-`abort_apply` instruction. Before this second instruction is executed,
-the coroutine is said to be "suspended", and the token represents a
-reference to its suspended activation record.
+`@yield_once_2`) result of a `begin_apply` is a "token", a special value which
+can only be used as the operand of an `end_apply`, `abort_apply`, or
+`end_borrow` instruction. Before this second instruction is executed, the
+coroutine is said to be "suspended", and the token represents a reference to its
+suspended activation record.
 
 If the coroutine's kind `yield_once_2`, its final result is an address
 of a "token", representing the allocation done by the callee
@@ -3451,6 +3473,20 @@ Constructs a statically initialized vector of elements. This instruction
 can only appear as final instruction in a global variable static
 initializer list.
 
+### vector_base_addr
+
+```
+sil-instruction ::= 'vector_base_addr' sil-operand
+
+%1 = vector_base_addr %0 : $*Builtin.FixedArray<N, Element>
+// %0 must have type $*Builtin.FixedArray
+// %1 will be of the element type of the Builtin.FixedArray
+```
+
+Derives the address of the first element of a vector, i.e. a `Builtin.FixedArray`,
+from the address of the vector itself.
+Addresses of other vector elements can then be derived with `index_addr`.
+
 ### ref_element_addr
 
 ```
diff --git a/docs/SIL/Ownership.md b/docs/SIL/Ownership.md
index 4a9f768f55832..52b2b5c4603a3 100644
--- a/docs/SIL/Ownership.md
+++ b/docs/SIL/Ownership.md
@@ -814,6 +814,11 @@ SILValue. Instead, it constrains the lifetime of an addressable
 variable. Since the constraint is applied to the in-memory
 representation, no additional lexical SILValue is required.
 
+The `self` function argument in a borrow accessor is not lexical.
+`self` is already borrowed for the duration of the borrow accessor and the
+dependency between borrowed return value and `self` will be represented in SIL,
+making lexical lifetime unnecessary.
+
 ### Deinit Barriers
 
 Deinit barriers (see Instruction.isDeinitBarrier(_:)) are instructions
diff --git a/docs/SIL/SIL.md b/docs/SIL/SIL.md
index 966a1adbd3303..d7cc716ca4f16 100644
--- a/docs/SIL/SIL.md
+++ b/docs/SIL/SIL.md
@@ -457,9 +457,10 @@ The ownership kind of a value is statically determined:
       ...
 ```
 
-- The ownership of most instruction results is statically defined. For example
-  `copy_value` always produces an owned value, whereas `begin_borrow` always
-  produces a guaranteed value.
+- The ownership of most instruction results can be statically determined from
+  the instruction's kind and the offset of the value in the result tuple. For
+  example `copy_value` has only one result and that result is always an owned
+  value, whereas `begin_borrow` always produces a guaranteed value.
 
 - Forwarding instructions: some instructions work with both, owned and
   guaranteed ownership, and "forward" the ownership from their operand(s) to
diff --git a/docs/SIL/Types.md b/docs/SIL/Types.md
index d35e5af2bc143..428432aea24c6 100644
--- a/docs/SIL/Types.md
+++ b/docs/SIL/Types.md
@@ -431,6 +431,44 @@ in the callee.
     `@sil_isolated` since a function cannot be isolated to multiple
     actors at the same time.
 
+-   SIL functions may optionally mark a function parameter as
+    `@sil_implicit_leading_param`. A SIL generator places this on a parameter
+    that is used to represent a parameter that is implicitly generated by the
+    generator at a full call site. Since they can only appear at the full call
+    site, a `@sil_implicit_leading_param` can only appear in between the
+    indirect result parameters and the direct parameters. For example the
+    following swift code that uses `nonisolated(nonsending)`:
+
+    ```
+    nonisolated(nonsending)
+    func f(_ x: DirectParam) -> IndirectResult {
+      ...
+    }
+    ```
+
+    would translate to the following SIL:
+
+    ```
+      sil [ossa] @f : $@convention(thin) @async (
+         @sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>,
+         @guaranteed DirectParam
+      ) -> @out IndirectResult {
+      bb0(%0 : $*IndirectResult, %1 : @guaranteed $Optional<Actor>, %2 : @guaranteed $DirectParam):
+        ... use %0 ...
+      }
+    ```
+
+    Notice how there is an `@sil_isolated` `@sil_implicit_leading_param`
+    parameter that was inserted by SILGen to implicitly take in the caller's
+    actor of f.
+
+    NOTE: By design SILOptimizer passes should ignore
+    `@sil_implicit_leading_param`. Instead, it should only be analyzed as a
+    normal parameter. So as an example, in f above the implicit parameter should
+    be treated by the optimizer just as any other isolated parameter. This is
+    solely SILGen using SIL as a data structure. TODO: Can this be removed by
+    SILGen so SILOptimizer passes cannot even see it?
+
 ### Async Functions
 
 SIL function types may be `@async`. `@async` functions run inside async
diff --git a/docs/WindowsBuild.md b/docs/WindowsBuild.md
index b20b7d4cb1ca4..a6822a43d75c0 100644
--- a/docs/WindowsBuild.md
+++ b/docs/WindowsBuild.md
@@ -128,7 +128,7 @@ cmake -B "S:\b\1" ^
   -D CMAKE_CXX_FLAGS="/GS- /Oy /Gw /Gy" ^
   -D CMAKE_EXE_LINKER_FLAGS="/INCREMENTAL:NO" ^
   -D CMAKE_MT=mt ^
-  -D CMAKE_SHARED_LINKER_FLAGS="/INCREMENTAL:NO" ^  
+  -D CMAKE_SHARED_LINKER_FLAGS="/INCREMENTAL:NO" ^
   -D LLVM_DEFAULT_TARGET_TRIPLE=x86_64-unknown-windows-msvc ^
   -D LLVM_ENABLE_PDB=YES ^
   -D LLVM_EXTERNAL_CMARK_SOURCE_DIR=S:\cmark ^
diff --git a/docs/proposals/archive/MemoryAndConcurrencyModel.rst b/docs/proposals/archive/MemoryAndConcurrencyModel.rst
index 9cc0d6122e057..bf924300731fc 100644
--- a/docs/proposals/archive/MemoryAndConcurrencyModel.rst
+++ b/docs/proposals/archive/MemoryAndConcurrencyModel.rst
@@ -11,7 +11,7 @@ Swift Memory and Concurrency Model
 
 The goal of this writeup is to provide a safe and efficient way to model,
 design, and implement concurrent applications in Swift. It is believed that it
-will completely eliminate data races and reduce deadlocks in swift apps, and
+will completely eliminate data races and reduce deadlocks in Swift apps, and
 will allow for important performance wins as well. This happens by eliminating
 shared mutable data, locks, and the need for most atomic memory accesses. The
 model is quite different from what traditional unix folks are used to
@@ -83,7 +83,7 @@ definition. These kinds are:
      b.list.data = 42 // error, can't change immutable data.
 
    As part of mutable data, it is worth pointing out that mutable "global
-   variables" in swift are not truly global, they are local to the current actor
+   variables" in Swift are not truly global, they are local to the current actor
    (somewhat similar to "thread local storage", or perhaps to "an ivar on the
    actor"). Immutable global variables (like lookup tables) are simple immutable
    data just like today. Global variables with "static constructors /
@@ -225,7 +225,7 @@ Performing synchronous operations
 ---------------------------------
 
 Asynchronous calls are nice and define away the possibility of deadlock, but at
-some point you need to get a return value back and async programming is very
+some point, you need to get a return value back and async programming is very
 awkward. To handle this, a 'synch' block is used. For example, the following is
 valid::
 
@@ -245,7 +245,7 @@ context.
 Memory Ownership Model
 ----------------------
 
-Within an actor there is a question of how ownership is handled. It's not in the
+Within an actor, there is a question of how ownership is handled. It's not in the
 scope of this document to say what the "one true model" is, but here are a
 couple of interesting observations:
 
@@ -265,7 +265,7 @@ couple of interesting observations:
    stop the world to do a collection. 2) actors have natural local quiescent
    points: when they have finished servicing a message, if their dispatch queue
    is empty, they go to sleep. If nothing else in the CPU needs the thread, it
-   would be a natural time to collect. 3) GC would be fully precise in swift,
+   would be a natural time to collect. 3) GC would be fully precise in Swift,
    unlike in ObjC, no conservative stack scanning or other hacks are needed. 4)
    If GC is used for mutable data, it would make sense to still use reference
    counting for actors themselves and especially for immutable data, meaning
diff --git a/include/swift-c/DependencyScan/DependencyScan.h b/include/swift-c/DependencyScan/DependencyScan.h
index b558643cbb850..988392265b27d 100644
--- a/include/swift-c/DependencyScan/DependencyScan.h
+++ b/include/swift-c/DependencyScan/DependencyScan.h
@@ -25,7 +25,7 @@
 /// SWIFTSCAN_VERSION_MINOR should increase when there are API additions.
 /// SWIFTSCAN_VERSION_MAJOR is intended for "major" source/ABI breaking changes.
 #define SWIFTSCAN_VERSION_MAJOR 2
-#define SWIFTSCAN_VERSION_MINOR 1
+#define SWIFTSCAN_VERSION_MINOR 2
 
 SWIFTSCAN_BEGIN_DECLS
 
@@ -36,7 +36,6 @@ typedef enum {
   // SwiftInterface and SwiftSource.
   SWIFTSCAN_DEPENDENCY_INFO_SWIFT_TEXTUAL = 0,
   SWIFTSCAN_DEPENDENCY_INFO_SWIFT_BINARY = 1,
-  SWIFTSCAN_DEPENDENCY_INFO_SWIFT_PLACEHOLDER = 2,
   SWIFTSCAN_DEPENDENCY_INFO_CLANG = 3
 } swiftscan_dependency_info_kind_t;
 
@@ -49,6 +48,9 @@ typedef struct swiftscan_dependency_info_s *swiftscan_dependency_info_t;
 /// Opaque container to a link library info.
 typedef struct swiftscan_link_library_info_s *swiftscan_link_library_info_t;
 
+/// Opaque container to an import info.
+typedef struct swiftscan_import_info_s *swiftscan_import_info_t;
+
 /// Opaque container to a macro dependency.
 typedef struct swiftscan_macro_dependency_s *swiftscan_macro_dependency_t;
 
@@ -76,6 +78,18 @@ typedef struct {
   size_t count;
 } swiftscan_link_library_set_t;
 
+/// Set of details about source imports
+typedef struct {
+  swiftscan_import_info_t *imports;
+  size_t count;
+} swiftscan_import_info_set_t;
+
+/// Set of source location infos
+typedef struct {
+  swiftscan_source_location_t *source_locations;
+  size_t count;
+} swiftscan_source_location_set_t;
+
 /// Set of macro dependency
 typedef struct {
   swiftscan_macro_dependency_t *macro_dependencies;
@@ -89,6 +103,15 @@ typedef enum {
   SWIFTSCAN_DIAGNOSTIC_SEVERITY_REMARK = 3
 } swiftscan_diagnostic_severity_t;
 
+// Must maintain consistency with swift::AccessLevel
+typedef enum {
+  SWIFTSCAN_ACCESS_LEVEL_PRIVATE = 0,
+  SWIFTSCAN_ACCESS_LEVEL_FILEPRIVATE = 1,
+  SWIFTSCAN_ACCESS_LEVEL_INTERNAL = 2,
+  SWIFTSCAN_ACCESS_LEVEL_PACKAGE = 3,
+  SWIFTSCAN_ACCESS_LEVEL_PUBLIC = 4
+} swiftscan_access_level_t;
+
 typedef struct {
   swiftscan_diagnostic_info_t *diagnostics;
   size_t count;
@@ -148,10 +171,23 @@ swiftscan_module_info_get_direct_dependencies(swiftscan_dependency_info_t info);
 SWIFTSCAN_PUBLIC swiftscan_link_library_set_t *
 swiftscan_module_info_get_link_libraries(swiftscan_dependency_info_t info);
 
+SWIFTSCAN_PUBLIC swiftscan_import_info_set_t *
+swiftscan_module_info_get_imports(swiftscan_dependency_info_t info);
+
 SWIFTSCAN_PUBLIC swiftscan_module_details_t
 swiftscan_module_info_get_details(swiftscan_dependency_info_t info);
 
-//=== Link Library Info Functions ------------------------------------===//
+//=== Import Details Functions -------------------------------------------===//
+SWIFTSCAN_PUBLIC swiftscan_source_location_set_t *
+swiftscan_import_info_get_source_locations(swiftscan_import_info_t info);
+
+SWIFTSCAN_PUBLIC swiftscan_string_ref_t
+swiftscan_import_info_get_identifier(swiftscan_import_info_t info);
+
+SWIFTSCAN_PUBLIC swiftscan_access_level_t
+swiftscan_import_info_get_access_level(swiftscan_import_info_t info);
+
+//=== Link Library Info Functions ----------------------------------------===//
 SWIFTSCAN_PUBLIC swiftscan_string_ref_t
 swiftscan_link_library_info_get_link_name(
     swiftscan_link_library_info_t info);
@@ -212,6 +248,10 @@ SWIFTSCAN_PUBLIC swiftscan_string_set_t *
 swiftscan_swift_textual_detail_get_swift_overlay_dependencies(
     swiftscan_module_details_t details);
 
+SWIFTSCAN_PUBLIC swiftscan_string_set_t *
+swiftscan_swift_textual_detail_get_swift_source_import_module_dependencies(
+swiftscan_module_details_t details);
+
 SWIFTSCAN_PUBLIC swiftscan_string_ref_t
 swiftscan_swift_textual_detail_get_cas_fs_root_id(
     swiftscan_module_details_t details);
@@ -269,7 +309,8 @@ swiftscan_swift_binary_detail_get_module_cache_key(
 SWIFTSCAN_PUBLIC swiftscan_string_ref_t
 swiftscan_swift_binary_detail_get_user_module_version(
     swiftscan_module_details_t details);
-//=== Swift Placeholder Module Details query APIs -------------------------===//
+
+//=== Swift Placeholder Module Details query APIs - DEPRECATED -----------===//
 
 SWIFTSCAN_PUBLIC swiftscan_string_ref_t
 swiftscan_swift_placeholder_detail_get_compiled_module_path(
diff --git a/include/swift/ABI/Executor.h b/include/swift/ABI/Executor.h
index 1257673826434..4f4fcf8927253 100644
--- a/include/swift/ABI/Executor.h
+++ b/include/swift/ABI/Executor.h
@@ -17,10 +17,10 @@
 #ifndef SWIFT_ABI_EXECUTOR_H
 #define SWIFT_ABI_EXECUTOR_H
 
-#include <inttypes.h>
 #include "swift/ABI/Actor.h"
 #include "swift/ABI/HeapObject.h"
 #include "swift/Runtime/Casting.h"
+#include <inttypes.h>
 
 namespace swift {
 class AsyncContext;
@@ -77,10 +77,10 @@ class SerialExecutorRef {
     /// Executor that may need to participate in complex "same context" checks,
     /// by invoking `isSameExclusiveExecutionContext` when comparing execution contexts.
     ComplexEquality = 0b01,
-    /// Mark this executor as the one used by `Task.startSynchronously`,
+    /// Mark this executor as the one used by `Task.immediate`,
     /// It cannot participate in switching.
     // TODO: Perhaps make this a generic "cannot switch" rather than start synchronously specific.
-    StartSynchronously = 0b10,
+    Immediate = 0b10,
   };
 
   static_assert(static_cast<uintptr_t>(ExecutorKind::Ordinary) == 0);
@@ -107,12 +107,12 @@ class SerialExecutorRef {
 
   static SerialExecutorRef forSynchronousStart() {
     auto wtable = reinterpret_cast<uintptr_t>(nullptr) |
-                  static_cast<uintptr_t>(ExecutorKind::StartSynchronously);
+                  static_cast<uintptr_t>(ExecutorKind::Immediate);
     return SerialExecutorRef(nullptr, wtable);
   }
   bool isForSynchronousStart() const {
     return getIdentity() == nullptr &&
-           getExecutorKind() == ExecutorKind::StartSynchronously;
+           getExecutorKind() == ExecutorKind::Immediate;
   }
 
   /// Given a pointer to a serial executor and its SerialExecutor
@@ -413,6 +413,23 @@ class AsyncFunctionPointer {
   uint32_t ExpectedContextSize;
 };
 
+/// Type-safe wrapper around the return value of `isIsolatingCurrentContext`.
+enum class IsIsolatingCurrentContextDecision : int8_t {
+  // The function call could not determine if the current context is isolated
+  // by this executor or not. Default value for executors which do not implement
+  // `isIsolatingCurrentContext`.
+  Unknown = -1,
+  // The current context is definitely not isolated by this executor.
+  NotIsolated = 0,
+  // The current context is definitely isolated by this executor.
+  Isolated = 1,
+};
+
+IsIsolatingCurrentContextDecision
+getIsIsolatingCurrentContextDecisionFromInt(int8_t value);
+
+StringRef getIsIsolatingCurrentContextDecisionNameStr(IsIsolatingCurrentContextDecision decision);
+
 }
 
 #endif
diff --git a/include/swift/ABI/Metadata.h b/include/swift/ABI/Metadata.h
index 0789767055800..bede849059198 100644
--- a/include/swift/ABI/Metadata.h
+++ b/include/swift/ABI/Metadata.h
@@ -2352,12 +2352,7 @@ struct TargetExtendedExistentialTypeShape
   }
   
   bool isCopyable() const {
-    if (!hasGeneralizationSignature()) {
-      return true;
-    }
-    auto *reqts = getGenSigRequirements();
-    for (unsigned i = 0, e = getNumGenSigRequirements(); i < e; ++i) {
-      auto &reqt = reqts[i];
+    for (auto &reqt : getRequirementSignature().getRequirements()) {
       if (reqt.getKind() != GenericRequirementKind::InvertedProtocols) {
         continue;
       }
@@ -2792,11 +2787,22 @@ using ResilientWitnessesHeader = TargetResilientWitnessesHeader<InProcess>;
 /// global actor protocol.
 template<typename Runtime>
 struct TargetGlobalActorReference {
+private:
+  using SignedDescriptorPointer =
+      const TargetProtocolConformanceDescriptor<Runtime>
+          *__ptrauth_swift_protocol_conformance_descriptor;
+
+public:
   /// The type of the global actor.
   RelativeDirectPointer<const char, /*nullable*/ false> type;
 
   /// The conformance of the global actor to the GlobalActor protocol.
-  TargetRelativeProtocolConformanceDescriptorPointer<Runtime> conformance;
+  RelativeIndirectablePointer<
+      const TargetProtocolConformanceDescriptor<Runtime>,
+      /*nullable*/ false,
+      /*offset*/ int32_t,
+      /*indirect type*/ SignedDescriptorPointer>
+      conformance;
 };
 
 /// Describes the context of a protocol conformance that is relevant when
@@ -2984,14 +2990,6 @@ struct TargetProtocolConformanceDescriptor final
     return Demangle::makeSymbolicMangledNameStringRef(this->template getTrailingObjects<TargetGlobalActorReference<Runtime>>()->type);
   }
 
-  /// True if this is a conformance to 'SerialExecutor' which has a non-default
-  /// (i.e. not the stdlib's default implementation) witness. This means that
-  /// the developer has implemented this method explicitly and we should prefer
-  /// calling it.
-  bool hasNonDefaultSerialExecutorIsIsolatingCurrentContext() const {
-    return Flags.hasNonDefaultSerialExecutorIsIsolatingCurrentContext();
-  }
-
   /// Retrieve the protocol conformance of the global actor type to the
   /// GlobalActor protocol.
   const TargetProtocolConformanceDescriptor<Runtime> *
diff --git a/include/swift/ABI/MetadataValues.h b/include/swift/ABI/MetadataValues.h
index 8007e3ab75e82..4e5e9b79d31b8 100644
--- a/include/swift/ABI/MetadataValues.h
+++ b/include/swift/ABI/MetadataValues.h
@@ -165,18 +165,19 @@ class TargetValueWitnessFlags {
   // flags for the struct. (The "non-inline" and "has-extra-inhabitants" bits
   // still require additional fixup.)
   enum : uint32_t {
-    AlignmentMask =          0x000000FF,
-    // unused                0x0000FF00,
-    IsNonPOD =               0x00010000,
-    IsNonInline =            0x00020000,
-    // unused                0x00040000,
-    HasSpareBits =           0x00080000,
-    IsNonBitwiseTakable =    0x00100000,
-    HasEnumWitnesses =       0x00200000,
-    Incomplete =             0x00400000,
-    IsNonCopyable =          0x00800000,
-    IsNonBitwiseBorrowable = 0x01000000,
-    // unused                0xFE000000,
+    AlignmentMask =                0x000000FF,
+    // unused                      0x0000FF00,
+    IsNonPOD =                     0x00010000,
+    IsNonInline =                  0x00020000,
+    // unused                      0x00040000,
+    HasSpareBits =                 0x00080000,
+    IsNonBitwiseTakable =          0x00100000,
+    HasEnumWitnesses =             0x00200000,
+    Incomplete =                   0x00400000,
+    IsNonCopyable =                0x00800000,
+    IsNonBitwiseBorrowable =       0x01000000,
+    IsAddressableForDependencies = 0x02000000,
+    // unused                      0xFC000000,
   };
 
   static constexpr const uint32_t MaxNumExtraInhabitants = 0x7FFFFFFF;
@@ -268,6 +269,19 @@ class TargetValueWitnessFlags {
     return TargetValueWitnessFlags((Data & ~IsNonCopyable) |
                                    (isCopyable ? 0 : IsNonCopyable));
   }
+  
+  /// True if values of this type are addressable-for-dependencies, meaning
+  /// that values of this type should be passed indirectly to functions that
+  /// produce lifetime-dependent values that could possibly contain pointers
+  /// to the inline storage of this type.
+  bool isAddressableForDependencies() const {
+    return Data & IsAddressableForDependencies;
+  }
+  constexpr TargetValueWitnessFlags withAddressableForDependencies(bool afd) const {
+    return TargetValueWitnessFlags((Data & ~IsAddressableForDependencies) |
+                                   (afd ? IsAddressableForDependencies : 0));
+  }
+
 
   /// True if this type's binary representation is that of an enum, and the
   /// enum value witness table entries are available in this type's value
@@ -374,8 +388,6 @@ class MethodDescriptorFlags {
     Setter,
     ModifyCoroutine,
     ReadCoroutine,
-    Read2Coroutine,
-    Modify2Coroutine,
   };
 
 private:
@@ -438,23 +450,27 @@ class MethodDescriptorFlags {
   /// Note that 'init' is not considered an instance member.
   bool isInstance() const { return Value & IsInstanceMask; }
 
-  bool isAsync() const { return Value & IsAsyncMask; }
+  bool _hasAsyncBitSet() const { return Value & IsAsyncMask; }
 
-  bool isCalleeAllocatedCoroutine() const {
+  bool isAsync() const { return !isCoroutine() && _hasAsyncBitSet(); }
+
+  bool isCoroutine() const {
     switch (getKind()) {
     case Kind::Method:
     case Kind::Init:
     case Kind::Getter:
     case Kind::Setter:
+      return false;
     case Kind::ModifyCoroutine:
     case Kind::ReadCoroutine:
-      return false;
-    case Kind::Read2Coroutine:
-    case Kind::Modify2Coroutine:
       return true;
     }
   }
 
+  bool isCalleeAllocatedCoroutine() const {
+    return isCoroutine() && _hasAsyncBitSet();
+  }
+
   bool isData() const { return isAsync() || isCalleeAllocatedCoroutine(); }
 
   uint16_t getExtraDiscriminator() const {
@@ -615,8 +631,6 @@ class ProtocolRequirementFlags {
     ModifyCoroutine,
     AssociatedTypeAccessFunction,
     AssociatedConformanceAccessFunction,
-    Read2Coroutine,
-    Modify2Coroutine,
   };
 
 private:
@@ -666,26 +680,30 @@ class ProtocolRequirementFlags {
   /// Note that 'init' is not considered an instance member.
   bool isInstance() const { return Value & IsInstanceMask; }
 
-  bool isAsync() const { return Value & IsAsyncMask; }
+  bool _hasAsyncBitSet() const { return Value & IsAsyncMask; }
 
-  bool isCalleeAllocatedCoroutine() const {
+  bool isAsync() const { return !isCoroutine() && _hasAsyncBitSet(); }
+
+  bool isCoroutine() const {
     switch (getKind()) {
     case Kind::BaseProtocol:
     case Kind::Method:
     case Kind::Init:
     case Kind::Getter:
     case Kind::Setter:
-    case Kind::ReadCoroutine:
-    case Kind::ModifyCoroutine:
     case Kind::AssociatedTypeAccessFunction:
     case Kind::AssociatedConformanceAccessFunction:
       return false;
-    case Kind::Read2Coroutine:
-    case Kind::Modify2Coroutine:
+    case Kind::ReadCoroutine:
+    case Kind::ModifyCoroutine:
       return true;
     }
   }
 
+  bool isCalleeAllocatedCoroutine() const {
+    return isCoroutine() && _hasAsyncBitSet();
+  }
+
   bool isData() const { return isAsync() || isCalleeAllocatedCoroutine(); }
 
   bool isSignedWithAddress() const {
@@ -750,14 +768,6 @@ class ConformanceFlags {
     IsConformanceOfProtocolMask = 0x01u << 18,
     HasGlobalActorIsolation = 0x01u << 19,
 
-    // Used to detect if this is a conformance to SerialExecutor that has
-    // an user defined implementation of 'isIsolatingCurrentContext'. This
-    // requirement is special in the sense that if a non-default impl is present
-    // we will avoid calling the `checkIsolated` method which would lead to a
-    // crash. In other words, this API "soft replaces" 'checkIsolated' so we
-    // must at runtime the presence of a non-default implementation.
-    HasNonDefaultSerialExecutorIsIsolatingCurrentContext = 0x01u << 20,
-
     NumConditionalPackDescriptorsMask = 0xFFu << 24,
     NumConditionalPackDescriptorsShift = 24
   };
@@ -824,15 +834,7 @@ class ConformanceFlags {
                                  : 0));
   }
 
-  ConformanceFlags withHasNonDefaultSerialExecutorIsIsolatingCurrentContext(
-                                           bool hasNonDefaultSerialExecutorIsIsolatingCurrentContext) const {
-    return ConformanceFlags((Value & ~HasNonDefaultSerialExecutorIsIsolatingCurrentContext)
-                            | (hasNonDefaultSerialExecutorIsIsolatingCurrentContext
-                                 ? HasNonDefaultSerialExecutorIsIsolatingCurrentContext
-                                 : 0));
-  }
-
-  /// Retrieve the type reference kind kind.
+  /// Retrieve the type reference kind.
   TypeReferenceKind getTypeReferenceKind() const {
     return TypeReferenceKind(
                       (Value & TypeMetadataKindMask) >> TypeMetadataKindShift);
@@ -876,10 +878,6 @@ class ConformanceFlags {
     return Value & HasGlobalActorIsolation;
   }
 
-  bool hasNonDefaultSerialExecutorIsIsolatingCurrentContext() const {
-    return Value & HasNonDefaultSerialExecutorIsIsolatingCurrentContext;
-  }
-
   /// Retrieve the # of conditional requirements.
   unsigned getNumConditionalRequirements() const {
     return (Value & NumConditionalRequirementsMask)
@@ -1295,7 +1293,7 @@ class TargetExtendedFunctionTypeFlags {
 
     // Values for the enumerated isolation kinds
     IsolatedAny            = 0x00000002U,
-    NonIsolatedCaller      = 0x00000004U,
+    NonIsolatedNonsending  = 0x00000004U,
 
     // Values if we have a sending result.
     HasSendingResult  = 0x00000010U,
@@ -1330,7 +1328,7 @@ class TargetExtendedFunctionTypeFlags {
   const TargetExtendedFunctionTypeFlags<int_type>
   withNonIsolatedCaller() const {
     return TargetExtendedFunctionTypeFlags<int_type>((Data & ~IsolationMask) |
-                                                     NonIsolatedCaller);
+                                                     NonIsolatedNonsending);
   }
 
   const TargetExtendedFunctionTypeFlags<int_type>
@@ -1354,7 +1352,7 @@ class TargetExtendedFunctionTypeFlags {
   }
 
   bool isNonIsolatedCaller() const {
-    return (Data & IsolationMask) == NonIsolatedCaller;
+    return (Data & IsolationMask) == NonIsolatedNonsending;
   }
 
   bool hasSendingResult() const {
@@ -1761,7 +1759,7 @@ namespace SpecialPointerAuthDiscriminators {
   const uint16_t AsyncContextParent = 0xbda2; // = 48546
   const uint16_t AsyncContextResume = 0xd707; // = 55047
   const uint16_t AsyncContextYield = 0xe207; // = 57863
-  const uint16_t CancellationNotificationFunction = 0x1933; // = 6451
+  const uint16_t CancellationNotificationFunction = 0x0f08; // = 3848
   const uint16_t EscalationNotificationFunction = 0x7861; // = 30817
   const uint16_t AsyncThinNullaryFunction = 0x0f08; // = 3848
   const uint16_t AsyncFutureFunction = 0x720f; // = 29199
@@ -2762,7 +2760,7 @@ class TaskCreateFlags : public FlagSet<size_t> {
     ///
     /// Supported starting in Swift 6.1.
     Task_IsTaskFunctionConsumed                   = 15,
-    Task_IsStartSynchronouslyTask                 = 16,
+    Task_IsImmediateTask                          = 16,
   };
 
   explicit constexpr TaskCreateFlags(size_t bits) : FlagSet(bits) {}
@@ -2795,9 +2793,9 @@ class TaskCreateFlags : public FlagSet<size_t> {
   FLAGSET_DEFINE_FLAG_ACCESSORS(Task_IsTaskFunctionConsumed,
                                 isTaskFunctionConsumed,
                                 setIsTaskFunctionConsumed)
-  FLAGSET_DEFINE_FLAG_ACCESSORS(Task_IsStartSynchronouslyTask,
-                                isSynchronousStartTask,
-                                setIsSYnchronousStartTask)
+  FLAGSET_DEFINE_FLAG_ACCESSORS(Task_IsImmediateTask,
+                                isImmediateTask,
+                                setIsImmediateTask)
 };
 
 /// Flags for schedulable jobs.
diff --git a/include/swift/ABI/ObjectFile.h b/include/swift/ABI/ObjectFile.h
index 2158215c4862f..fddf9c7e064e2 100644
--- a/include/swift/ABI/ObjectFile.h
+++ b/include/swift/ABI/ObjectFile.h
@@ -83,7 +83,7 @@ class SwiftObjectFileFormatELF : public SwiftObjectFileFormat {
   }
 };
 
-/// Responsible for providing the COFF reflection section identifiers
+/// Responsible for providing the COFF reflection section identifiers.
 class SwiftObjectFileFormatCOFF : public SwiftObjectFileFormat {
 public:
   llvm::StringRef getSectionName(ReflectionSectionKind section) override {
@@ -101,5 +101,28 @@ class SwiftObjectFileFormatCOFF : public SwiftObjectFileFormat {
     return sectionName.starts_with(".sw5");
   }
 };
+
+/// Responsible for providing the WebAssembly reflection section identifiers.
+/// WebAssembly binaries store all reflection metadata in the DATA
+/// section. There are symbols for each reflection section kind in the "name"
+/// section that point to the corresponding offset inside DATA.
+class SwiftObjectFileFormatWasm : public SwiftObjectFileFormat {
+public:
+  llvm::StringRef getSectionName(ReflectionSectionKind section) override {
+    switch (section) {
+#define HANDLE_SWIFT_SECTION(KIND, MACHO, ELF, COFF)                           \
+  case KIND:                                                                   \
+    return ELF;
+#include "llvm/BinaryFormat/Swift.def"
+#undef HANDLE_SWIFT_SECTION
+    }
+    llvm_unreachable("Section  not found.");
+  }
+
+  bool sectionContainsReflectionData(llvm::StringRef sectionName) override {
+    return sectionName.starts_with("swift5_");
+  }
+};
+
 } // namespace swift
 #endif // SWIFT_ABI_OBJECTFILE_H
diff --git a/include/swift/ABI/Task.h b/include/swift/ABI/Task.h
index a81ffdfdfa764..e80fd3b889559 100644
--- a/include/swift/ABI/Task.h
+++ b/include/swift/ABI/Task.h
@@ -29,6 +29,17 @@
 #include "bitset"
 #include "queue" // TODO: remove and replace with our own mpsc
 
+// Does the runtime provide priority escalation support?
+#ifndef SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION
+#if SWIFT_CONCURRENCY_ENABLE_DISPATCH && \
+    __has_include(<dispatch/swift_concurrency_private.h>) && __APPLE__ && \
+    (defined(__arm64__) || defined(__x86_64__))
+#define SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION 1
+#else
+#define SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION 0
+#endif
+#endif /* SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION */
+
 namespace swift {
 class AsyncTask;
 class AsyncContext;
@@ -143,6 +154,10 @@ class alignas(2 * alignof(void*)) Job :
     return Flags.getPriority();
   }
 
+  void setPriority(JobPriority priority) {
+    Flags.setPriority(priority);
+  }
+
   uint32_t getJobId() const {
     return Id;
   }
@@ -226,10 +241,10 @@ struct ResultTypeInfo {
 #else
   size_t size = 0;
   size_t alignMask = 0;
-  void (*initializeWithCopy)(OpaqueValue *result, OpaqueValue *src) = nullptr;
+  OpaqueValue * (*initializeWithCopy)(OpaqueValue *result, OpaqueValue *src, void *type) = nullptr;
   void (*storeEnumTagSinglePayload)(OpaqueValue *v, unsigned whichCase,
-                                    unsigned emptyCases) = nullptr;
-  void (*destroy)(OpaqueValue *) = nullptr;
+                                    unsigned emptyCases, void *type) = nullptr;
+  void (*destroy)(OpaqueValue *, void *) = nullptr;
 
   bool isNull() {
     return initializeWithCopy == nullptr;
@@ -241,14 +256,14 @@ struct ResultTypeInfo {
     return alignMask + 1;
   }
   void vw_initializeWithCopy(OpaqueValue *result, OpaqueValue *src) {
-    initializeWithCopy(result, src);
+    initializeWithCopy(result, src, nullptr);
   }
   void vw_storeEnumTagSinglePayload(OpaqueValue *v, unsigned whichCase,
                                     unsigned emptyCases) {
-    storeEnumTagSinglePayload(v, whichCase, emptyCases);
+    storeEnumTagSinglePayload(v, whichCase, emptyCases, nullptr);
   }
   void vw_destroy(OpaqueValue *v) {
-    destroy(v);
+    destroy(v, nullptr);
   }
 #endif
 };
@@ -301,15 +316,16 @@ class AsyncTask : public Job {
 #if SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION && SWIFT_POINTER_IS_4_BYTES
     static constexpr size_t ActiveTaskStatusSize = 4 * sizeof(void *);
 #else
-    static constexpr size_t ActiveTaskStatusSize = 4 * sizeof(void *);
+    static constexpr size_t ActiveTaskStatusSize = 2 * sizeof(void *);
 #endif
 
     // Private storage is currently 6 pointers, 16 bytes of non-pointer data,
-    // the ActiveTaskStatus, and a RecursiveMutex.
+    // 8 bytes of padding, the ActiveTaskStatus, and a RecursiveMutex.
     static constexpr size_t PrivateStorageSize =
-        6 * sizeof(void *) + 16 + ActiveTaskStatusSize + sizeof(RecursiveMutex);
+      6 * sizeof(void *) + 16 + 8 + ActiveTaskStatusSize
+      + sizeof(RecursiveMutex);
 
-    void *Storage[PrivateStorageSize];
+    char Storage[PrivateStorageSize];
 
     /// Initialize this storage during the creation of a task.
     void initialize(JobPriority basePri);
diff --git a/include/swift/ABI/TaskGroup.h b/include/swift/ABI/TaskGroup.h
index b1c821d8e1cba..03f7e101cce06 100644
--- a/include/swift/ABI/TaskGroup.h
+++ b/include/swift/ABI/TaskGroup.h
@@ -44,6 +44,12 @@ class alignas(Alignment_TaskGroup) TaskGroup {
   /// Checks the cancellation status of the group.
   bool isCancelled();
 
+  /// Only mark the task group as cancelled, without performing the follow-up
+  /// work of cancelling all the child tasks.
+  ///
+  /// Returns true if the group was already cancelled before this call.
+  bool statusCancel();
+
   // Add a child task to the task group. Always called while holding the
   // status record lock of the task group's owning task.
   void addChildTask(AsyncTask *task);
diff --git a/include/swift/ABI/TaskOptions.h b/include/swift/ABI/TaskOptions.h
index f1b8448e3841f..029b031f0e95e 100644
--- a/include/swift/ABI/TaskOptions.h
+++ b/include/swift/ABI/TaskOptions.h
@@ -199,7 +199,7 @@ class AsyncLetWithBufferTaskOptionRecord : public TaskOptionRecord {
   AsyncLet *getAsyncLet() const {
     return asyncLet;
   }
-  
+
   void *getResultBuffer() const {
     return resultBuffer;
   }
@@ -215,16 +215,16 @@ class ResultTypeInfoTaskOptionRecord : public TaskOptionRecord {
   size_t size;
   size_t alignMask;
 
-  void (*__ptrauth_swift_value_witness_function_pointer(
+  OpaqueValue *(*__ptrauth_swift_value_witness_function_pointer(
       SpecialPointerAuthDiscriminators::InitializeWithCopy)
-            initializeWithCopy)(OpaqueValue *, OpaqueValue *);
+            initializeWithCopy)(OpaqueValue *, OpaqueValue *, void *);
 
   void (*__ptrauth_swift_value_witness_function_pointer(
       SpecialPointerAuthDiscriminators::StoreEnumTagSinglePayload)
-            storeEnumTagSinglePayload)(OpaqueValue *, unsigned, unsigned);
+            storeEnumTagSinglePayload)(OpaqueValue *, unsigned, unsigned, void *);
 
   void (*__ptrauth_swift_value_witness_function_pointer(
-      SpecialPointerAuthDiscriminators::Destroy) destroy)(OpaqueValue *);
+      SpecialPointerAuthDiscriminators::Destroy) destroy)(OpaqueValue *, void *);
 
   static bool classof(const TaskOptionRecord *record) {
     return record->getKind() == TaskOptionRecordKind::ResultTypeInfo;
diff --git a/include/swift/ABI/TaskStatus.h b/include/swift/ABI/TaskStatus.h
index 2d5a3daf5e21d..56718978e8245 100644
--- a/include/swift/ABI/TaskStatus.h
+++ b/include/swift/ABI/TaskStatus.h
@@ -269,7 +269,7 @@ class CancellationNotificationStatusRecord : public TaskStatusRecord {
 /// subsequently used.
 class EscalationNotificationStatusRecord : public TaskStatusRecord {
 public:
-  using FunctionType = SWIFT_CC(swift) void(JobPriority, JobPriority, SWIFT_CONTEXT void *);
+  using FunctionType = SWIFT_CC(swift) void(uint8_t, uint8_t, SWIFT_CONTEXT void *);
 
 private:
   FunctionType *__ptrauth_swift_escalation_notification_function Function;
@@ -282,7 +282,10 @@ class EscalationNotificationStatusRecord : public TaskStatusRecord {
   }
 
   void run(JobPriority oldPriority, JobPriority newPriority) {
-    Function(oldPriority, newPriority, Argument);
+    Function(
+      static_cast<size_t>(oldPriority),
+      static_cast<size_t>(newPriority),
+      Argument);
   }
 
   static bool classof(const TaskStatusRecord *record) {
diff --git a/include/swift/APIDigester/ModuleAnalyzerNodes.h b/include/swift/APIDigester/ModuleAnalyzerNodes.h
index b6887711eb13b..b698bf04b382a 100644
--- a/include/swift/APIDigester/ModuleAnalyzerNodes.h
+++ b/include/swift/APIDigester/ModuleAnalyzerNodes.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -17,11 +17,6 @@
 #ifndef __SWIFT_ABI_DIGESTER_MODULE_NODES_H__
 #define __SWIFT_ABI_DIGESTER_MODULE_NODES_H__
 
-#include "clang/AST/ASTContext.h"
-#include "clang/AST/DeclObjC.h"
-#include "clang/Lex/Preprocessor.h"
-#include "clang/Sema/Lookup.h"
-#include "clang/Sema/Sema.h"
 #include "llvm/ADT/TinyPtrVector.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/CommandLine.h"
@@ -242,7 +237,9 @@ class SDKContext {
   void diagnose(YAMLNodeTy node, Diag<ArgTypes...> ID,
                 typename detail::PassArgument<ArgTypes>::type... args) {
     auto smRange = node->getSourceRange();
-    auto range = SourceRange(SourceLoc(smRange.Start), SourceLoc(smRange.End));
+    auto range =
+        SourceRange(SourceLoc::getFromPointer(smRange.Start.getPointer()),
+                    SourceLoc::getFromPointer(smRange.End.getPointer()));
     Diags.diagnose(range.Start, ID, std::forward<ArgTypes>(args)...)
       .highlight(range);
   }
diff --git a/include/swift/AST/ASTBridging.h b/include/swift/AST/ASTBridging.h
index 31cce3d1ff0c2..ec88cb660a4f0 100644
--- a/include/swift/AST/ASTBridging.h
+++ b/include/swift/AST/ASTBridging.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
+// Copyright (c) 2022 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -13,15 +13,21 @@
 #ifndef SWIFT_AST_ASTBRIDGING_H
 #define SWIFT_AST_ASTBRIDGING_H
 
-// Do not add other C++/llvm/swift header files here!
-// Function implementations should be placed into ASTBridging.cpp and required header files should be added there.
-//
-// Pure bridging mode does not permit including any C++/llvm/swift headers.
-// See also the comments for `BRIDGING_MODE` in the top-level CMakeLists.txt file.
-//
+/// `ASTBridging.h` is imported into Swift. Be *very* careful with what you
+/// include here and keep these includes minimal!
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
+#include "swift/AST/AccessorKind.h"
+#include "swift/AST/AttrKind.h"
+#include "swift/AST/DiagnosticKind.h"
+#include "swift/AST/DiagnosticList.h"
+#include "swift/AST/GenericTypeParamKind.h"
+#include "swift/AST/Identifier.h"
+#include "swift/AST/LayoutConstraintKind.h"
+#include "swift/AST/PlatformKind.h"
 #include "swift/Basic/BasicBridging.h"
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 #include "swift/AST/Attr.h"
 #include "swift/AST/Decl.h"
 #endif
@@ -52,6 +58,7 @@ class IfConfigClauseRangeInfo;
 class GenericSignature;
 class GenericSignatureImpl;
 struct LabeledStmtInfo;
+class LangOptions;
 class LayoutConstraint;
 class LayoutConstraintInfo;
 struct LifetimeDescriptor;
@@ -60,7 +67,6 @@ class MacroIntroducedDeclName;
 enum class MacroIntroducedDeclNameKind;
 enum class ParamSpecifier : uint8_t;
 class ParsedAutoDiffParameter;
-enum class PlatformKind : uint8_t;
 class ProtocolConformanceRef;
 class RegexLiteralPatternFeature;
 class RegexLiteralPatternFeatureKind;
@@ -71,16 +77,17 @@ class CanType;
 class TypeBase;
 class StmtConditionElement;
 class SubstitutionMap;
+enum class RequirementReprKind : unsigned;
 }
 
 struct BridgedASTType;
 class BridgedCanType;
 class BridgedASTContext;
+class BridgedLangOptions;
 struct BridgedSubstitutionMap;
 struct BridgedGenericSignature;
 struct BridgedConformance;
 class BridgedParameterList;
-enum BridgedPlatformKind : size_t;
 
 // Forward declare the underlying AST node type for each wrapper.
 namespace swift {
@@ -107,43 +114,20 @@ namespace swift {
 // MARK: Identifier
 //===----------------------------------------------------------------------===//
 
-class BridgedIdentifier {
-public:
-  SWIFT_UNAVAILABLE("Use '.raw' instead")
-  const void *_Nullable Raw;
-
-  BridgedIdentifier() : Raw(nullptr) {}
-
-  SWIFT_NAME("init(raw:)")
-  BridgedIdentifier(const void *_Nullable raw) : Raw(raw) {}
-
-  BRIDGED_INLINE BridgedIdentifier(swift::Identifier ident);
-
-  BRIDGED_INLINE swift::Identifier unbridged() const;
-};
-
-SWIFT_NAME("getter:BridgedIdentifier.raw(self:)")
-inline const void *_Nullable BridgedIdentifier_raw(BridgedIdentifier ident) {
-  return ident.Raw;
-}
-
-SWIFT_NAME("getter:BridgedIdentifier.isOperator(self:)")
-BRIDGED_INLINE bool BridgedIdentifier_isOperator(const BridgedIdentifier);
-
 struct BridgedLocatedIdentifier {
   SWIFT_NAME("name")
-  BridgedIdentifier Name;
+  swift::Identifier Name;
 
   SWIFT_NAME("nameLoc")
-  BridgedSourceLoc NameLoc;
+  swift::SourceLoc NameLoc;
 };
 
 struct BridgedConsumedLookupResult {
   SWIFT_NAME("name")
-  BridgedIdentifier Name;
+  swift::Identifier Name;
 
   SWIFT_NAME("nameLoc")
-  BridgedSourceLoc NameLoc;
+  swift::SourceLoc NameLoc;
 
   SWIFT_NAME("flag")
   SwiftInt Flag;
@@ -153,28 +137,6 @@ struct BridgedConsumedLookupResult {
                                              SwiftInt flag);
 };
 
-class BridgedDeclBaseName {
-  BridgedIdentifier Ident;
-
-public:
-  BRIDGED_INLINE BridgedDeclBaseName(swift::DeclBaseName baseName);
-
-  BRIDGED_INLINE swift::DeclBaseName unbridged() const;
-};
-
-SWIFT_NAME("BridgedDeclBaseName.createConstructor()")
-BridgedDeclBaseName BridgedDeclBaseName_createConstructor();
-
-SWIFT_NAME("BridgedDeclBaseName.createDestructor()")
-BridgedDeclBaseName BridgedDeclBaseName_createDestructor();
-
-SWIFT_NAME("BridgedDeclBaseName.createSubscript()")
-BridgedDeclBaseName BridgedDeclBaseName_createSubscript();
-
-SWIFT_NAME("BridgedDeclBaseName.createIdentifier(_:)")
-BridgedDeclBaseName
-BridgedDeclBaseName_createIdentifier(BridgedIdentifier identifier);
-
 class BridgedDeclNameRef {
   void *_Nullable opaque;
 
@@ -187,14 +149,13 @@ class BridgedDeclNameRef {
 };
 
 SWIFT_NAME("BridgedDeclNameRef.createParsed(_:baseName:argumentLabels:)")
-BridgedDeclNameRef
-BridgedDeclNameRef_createParsed(BridgedASTContext cContext,
-                                BridgedDeclBaseName cBaseName,
-                                BridgedArrayRef cLabels);
+BridgedDeclNameRef BridgedDeclNameRef_createParsed(BridgedASTContext cContext,
+                                                   swift::DeclBaseName baseName,
+                                                   BridgedArrayRef cLabels);
 
 SWIFT_NAME("BridgedDeclNameRef.createParsed(_:)")
 BridgedDeclNameRef
-BridgedDeclNameRef_createParsed(BridgedDeclBaseName cBaseName);
+BridgedDeclNameRef_createParsed(swift::DeclBaseName baseName);
 
 class BridgedDeclNameLoc {
   const void *_Nullable LocationInfo;
@@ -210,14 +171,29 @@ class BridgedDeclNameLoc {
 
 SWIFT_NAME("BridgedDeclNameLoc.createParsed(_:baseNameLoc:lParenLoc:"
            "argumentLabelLocs:rParenLoc:)")
+BridgedDeclNameLoc BridgedDeclNameLoc_createParsed(BridgedASTContext cContext,
+                                                   swift::SourceLoc baseNameLoc,
+                                                   swift::SourceLoc lParenLoc,
+                                                   BridgedArrayRef cLabelLocs,
+                                                   swift::SourceLoc rParenLoc);
+
+SWIFT_NAME("BridgedDeclNameLoc.createParsed(_:moduleSelectorLoc:baseNameLoc:"
+           "lParenLoc:argumentLabelLocs:rParenLoc:)")
 BridgedDeclNameLoc BridgedDeclNameLoc_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cBaseNameLoc,
-    BridgedSourceLoc cLParenLoc, BridgedArrayRef cLabelLocs,
-    BridgedSourceLoc cRParenLoc);
+    BridgedASTContext cContext, swift::SourceLoc cModuleSelectorLoc,
+    swift::SourceLoc baseNameLoc, swift::SourceLoc lParenLoc,
+    BridgedArrayRef cLabelLocs, swift::SourceLoc rParenLoc);
 
 SWIFT_NAME("BridgedDeclNameLoc.createParsed(_:)")
 BridgedDeclNameLoc
-BridgedDeclNameLoc_createParsed(BridgedSourceLoc cBaseNameLoc);
+BridgedDeclNameLoc_createParsed(swift::SourceLoc baseNameLoc);
+
+SWIFT_NAME("BridgedDeclNameLoc.createParsed(_:moduleSelectorLoc:baseNameLoc:)")
+BridgedDeclNameLoc
+BridgedDeclNameLoc_createParsed(BridgedASTContext cContext,
+                                swift::SourceLoc moduleSelectorLoc,
+                                swift::SourceLoc baseNameLoc);
+
 
 //===----------------------------------------------------------------------===//
 // MARK: ASTContext
@@ -232,17 +208,26 @@ class BridgedASTContext {
 
   SWIFT_UNAVAILABLE("Use '.raw' instead")
   BRIDGED_INLINE swift::ASTContext &unbridged() const;
+
+  SWIFT_COMPUTED_PROPERTY
+  void *_Nonnull getRaw() const { return Ctx; }
+
+  SWIFT_COMPUTED_PROPERTY
+  unsigned getMajorLanguageVersion() const;
+
+  SWIFT_COMPUTED_PROPERTY
+  BridgedAvailabilityMacroMap getAvailabilityMacroMap() const;
+
+  SWIFT_COMPUTED_PROPERTY
+  BridgedDiagnosticEngine getDiags() const;
 };
 
-#define IDENTIFIER_WITH_NAME(Name, _) \
-SWIFT_NAME("getter:BridgedASTContext.id_" #Name "(self:)") \
-BRIDGED_INLINE BridgedIdentifier BridgedASTContext_id_##Name(BridgedASTContext bridged);
+#define IDENTIFIER_WITH_NAME(Name, _)                                          \
+  SWIFT_NAME("getter:BridgedASTContext.id_" #Name "(self:)")                   \
+  BRIDGED_INLINE swift::Identifier BridgedASTContext_id_##Name(                \
+      BridgedASTContext bridged);
 #include "swift/AST/KnownIdentifiers.def"
 
-SWIFT_NAME("getter:BridgedASTContext.raw(self:)")
-BRIDGED_INLINE
-void * _Nonnull BridgedASTContext_raw(BridgedASTContext bridged);
-
 SWIFT_NAME("BridgedASTContext.init(raw:)")
 BRIDGED_INLINE
 BridgedASTContext BridgedASTContext_fromRaw(void * _Nonnull ptr);
@@ -259,85 +244,19 @@ BridgedASTContext_allocateCopyString(BridgedASTContext cContext,
                                      BridgedStringRef cStr);
 
 SWIFT_NAME("BridgedASTContext.getIdentifier(self:_:)")
-BridgedIdentifier BridgedASTContext_getIdentifier(BridgedASTContext cContext,
+swift::Identifier BridgedASTContext_getIdentifier(BridgedASTContext cContext,
                                                   BridgedStringRef cStr);
 
 SWIFT_NAME("BridgedASTContext.getDollarIdentifier(self:_:)")
-BridgedIdentifier
+swift::Identifier
 BridgedASTContext_getDollarIdentifier(BridgedASTContext cContext, size_t idx);
 
-SWIFT_NAME("BridgedASTContext.langOptsHasFeature(self:_:)")
-bool BridgedASTContext_langOptsHasFeature(BridgedASTContext cContext,
-                                          BridgedFeature feature);
-
-SWIFT_NAME("getter:BridgedASTContext.majorLanguageVersion(self:)")
-unsigned BridgedASTContext_majorLanguageVersion(BridgedASTContext cContext);
-
-SWIFT_NAME("BridgedASTContext.langOptsCustomConditionSet(self:_:)")
-bool BridgedASTContext_langOptsCustomConditionSet(BridgedASTContext cContext,
-                                                  BridgedStringRef cName);
-
-SWIFT_NAME("BridgedASTContext.langOptsHasFeatureNamed(self:_:)")
-bool BridgedASTContext_langOptsHasFeatureNamed(BridgedASTContext cContext,
-                                               BridgedStringRef cName);
-
-SWIFT_NAME("BridgedASTContext.langOptsHasAttributeNamed(self:_:)")
-bool BridgedASTContext_langOptsHasAttributeNamed(BridgedASTContext cContext,
-                                                 BridgedStringRef cName);
-
-SWIFT_NAME("BridgedASTContext.langOptsIsActiveTargetOS(self:_:)")
-bool BridgedASTContext_langOptsIsActiveTargetOS(BridgedASTContext cContext,
-                                                BridgedStringRef cName);
-
-SWIFT_NAME("BridgedASTContext.langOptsIsActiveTargetArchitecture(self:_:)")
-bool BridgedASTContext_langOptsIsActiveTargetArchitecture(BridgedASTContext cContext,
-                                                          BridgedStringRef cName);
-
-SWIFT_NAME("BridgedASTContext.langOptsIsActiveTargetEnvironment(self:_:)")
-bool BridgedASTContext_langOptsIsActiveTargetEnvironment(BridgedASTContext cContext,
-                                                         BridgedStringRef cName);
-
-SWIFT_NAME("BridgedASTContext.langOptsIsActiveTargetRuntime(self:_:)")
-bool BridgedASTContext_langOptsIsActiveTargetRuntime(BridgedASTContext cContext,
-                                                     BridgedStringRef cName);
-
-SWIFT_NAME("BridgedASTContext.langOptsIsActiveTargetPtrAuth(self:_:)")
-bool BridgedASTContext_langOptsIsActiveTargetPtrAuth(BridgedASTContext cContext,
-                                                     BridgedStringRef cName);
-
-SWIFT_NAME("getter:BridgedASTContext.langOptsTargetPointerBitWidth(self:)")
-unsigned BridgedASTContext_langOptsTargetPointerBitWidth(BridgedASTContext cContext);
-
-SWIFT_NAME("BridgedASTContext.langOptsGetTargetAtomicBitWidths(self:_:)")
-SwiftInt BridgedASTContext_langOptsGetTargetAtomicBitWidths(BridgedASTContext cContext,
-                                                      SwiftInt* _Nullable * _Nonnull cComponents);
-
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedEndianness : size_t {
-  EndianLittle,
-  EndianBig,
-};
-
-SWIFT_NAME("getter:BridgedASTContext.langOptsAttachCommentsToDecls(self:)")
-bool BridgedASTContext_langOptsAttachCommentsToDecls(
-    BridgedASTContext cContext);
+SWIFT_NAME("getter:BridgedASTContext.langOpts(self:)")
+BridgedLangOptions BridgedASTContext_langOpts(BridgedASTContext cContext);
 
-SWIFT_NAME("getter:BridgedASTContext.langOptsTargetEndianness(self:)")
-BridgedEndianness BridgedASTContext_langOptsTargetEndianness(BridgedASTContext cContext);
-
-SWIFT_NAME("BridgedASTContext.langOptsGetLanguageVersion(self:_:)")
-SwiftInt BridgedASTContext_langOptsGetLanguageVersion(BridgedASTContext cContext,
-                                                      SwiftInt* _Nullable * _Nonnull cComponents);
-
-SWIFT_NAME("BridgedASTContext.langOptsGetCompilerVersion(self:_:)")
-SwiftInt BridgedASTContext_langOptsGetCompilerVersion(BridgedASTContext cContext,
-                                                      SwiftInt* _Nullable * _Nonnull cComponents);
-
-SWIFT_NAME("getter:BridgedASTContext.availabilityMacroMap(self:)")
-BridgedAvailabilityMacroMap
-BridgedASTContext_getAvailabilityMacroMap(BridgedASTContext cContext);
-
-/* Deallocate an array of Swift int values that was allocated in C++. */
-void deallocateIntBuffer(SwiftInt * _Nullable cComponents);
+SWIFT_NAME("BridgedLangOptions.hasAttributeNamed(self:_:)")
+bool BridgedLangOptions_hasAttributeNamed(BridgedLangOptions cLangOpts,
+                                          BridgedStringRef cName);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedCanImportVersion : size_t {
   CanImportUnversioned,
@@ -348,11 +267,14 @@ enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedCanImportVersion : size_t {
 SWIFT_NAME("BridgedASTContext.canImport(self:importPath:location:versionKind:versionComponents:numVersionComponents:)")
 bool BridgedASTContext_canImport(BridgedASTContext cContext,
                                  BridgedStringRef importPath,
-                                 BridgedSourceLoc canImportLoc,
+                                 swift::SourceLoc canImportLoc,
                                  BridgedCanImportVersion versionKind,
-                                 const SwiftInt * _Nullable versionComponents,
+                                 const SwiftInt *_Nullable versionComponents,
                                  SwiftInt numVersionComponents);
 
+SWIFT_NAME("getter:BridgedASTContext.staticBuildConfigurationPtr(self:)")
+void * _Nonnull BridgedASTContext_staticBuildConfiguration(BridgedASTContext cContext);
+
 //===----------------------------------------------------------------------===//
 // MARK: AST nodes
 //===----------------------------------------------------------------------===//
@@ -361,12 +283,22 @@ void registerBridgedDecl(BridgedStringRef bridgedClassName, SwiftMetatype metaty
 
 struct OptionalBridgedDeclObj {
   OptionalSwiftObject obj;
+
+  OptionalBridgedDeclObj(OptionalSwiftObject obj) : obj(obj) {}
+
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+  template <class D> D *_Nullable getAs() const {
+    if (obj)
+      return llvm::cast<D>(static_cast<swift::Decl *>(obj));
+    return nullptr;
+  }
+#endif
 };
 
 struct BridgedDeclObj {
   SwiftObject obj;
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
   template <class D> D *_Nonnull getAs() const {
     return llvm::cast<D>(static_cast<swift::Decl *>(obj));
   }
@@ -377,22 +309,27 @@ struct BridgedDeclObj {
 
   BridgedDeclObj(SwiftObject obj) : obj(obj) {}
   BridgedOwnedString getDebugDescription() const;
-  BRIDGED_INLINE BridgedSourceLoc getLoc() const;
+  BRIDGED_INLINE swift::SourceLoc getLoc() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj getModuleContext() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDeclObj getParent() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef Type_getName() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef Value_getUserFacingName() const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSourceLoc Value_getNameLoc() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE swift::SourceLoc Value_getNameLoc() const;
   BRIDGED_INLINE bool hasClangNode() const;
   BRIDGED_INLINE bool Value_isObjC() const;
   BRIDGED_INLINE bool AbstractStorage_isConst() const;
   BRIDGED_INLINE bool GenericType_isGenericAtAnyLevel() const;
   BRIDGED_INLINE bool NominalType_isGlobalActor() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDeclObj NominalType_getValueTypeDestructor() const;
+  BRIDGED_INLINE bool Enum_hasRawType() const;
   BRIDGED_INLINE bool Struct_hasUnreferenceableStorage() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType Class_getSuperclass() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj Class_getDestructor() const;
+  BRIDGED_INLINE bool ProtocolDecl_requiresClass() const;
   BRIDGED_INLINE bool AbstractFunction_isOverridden() const;
   BRIDGED_INLINE bool Destructor_isIsolated() const;
+  BRIDGED_INLINE bool EnumElementDecl_hasAssociatedValues() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef AccessorDecl_getKindName() const;
 };
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedASTNodeKind : uint8_t {
@@ -425,7 +362,7 @@ class BridgedASTNode {
     return BridgedASTNode(e.unbridged(), BridgedASTNodeKindExpr);
   }
 
-  SWIFT_UNAVAILABLE("use .kind")
+  SWIFT_COMPUTED_PROPERTY
   BridgedASTNodeKind getKind() const {
     return static_cast<BridgedASTNodeKind>(opaque & 0x7);
   }
@@ -437,11 +374,6 @@ class BridgedASTNode {
   BRIDGED_INLINE swift::ASTNode unbridged() const;
 };
 
-SWIFT_NAME("getter:BridgedASTNode.kind(self:)")
-inline BridgedASTNodeKind BridgedASTNode_getKind(BridgedASTNode node) {
-  return node.getKind();
-}
-
 // Declare `.asDecl` on each BridgedXXXDecl type, which upcasts a wrapper for
 // a Decl subclass to a BridgedDecl.
 #define DECL(Id, Parent)                                                       \
@@ -511,29 +443,15 @@ inline BridgedASTNodeKind BridgedASTNode_getKind(BridgedASTNode node) {
 
 struct BridgedPatternBindingEntry {
   BridgedPattern pattern;
-  BridgedSourceLoc equalLoc;
+  swift::SourceLoc equalLoc;
   BridgedNullableExpr init;
   BridgedNullablePatternBindingInitializer initContext;
 };
 
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedAccessorKind {
-#define ACCESSOR(ID) BridgedAccessorKind##ID,
-#include "swift/AST/AccessorKinds.def"
-};
-
-swift::AccessorKind unbridged(BridgedAccessorKind kind);
-
 //===----------------------------------------------------------------------===//
 // MARK: Diagnostic Engine
 //===----------------------------------------------------------------------===//
 
-// NOTE: This must be the same underlying value as C++ 'swift::DiagID' defined
-// in 'DiagnosticList.cpp'.
-enum ENUM_EXTENSIBILITY_ATTR(open) BridgedDiagID : uint32_t {
-#define DIAG(KIND, ID, Group, Options, Text, Signature) BridgedDiagID_##ID,
-#include "swift/AST/DiagnosticsAll.def"
-};
-
 class BridgedDiagnosticArgument {
   int64_t storage[3];
 
@@ -547,7 +465,7 @@ class BridgedDiagnosticArgument {
 
 class BridgedFixIt {
 public:
-  BridgedCharSourceRange replacementRange;
+  swift::CharSourceRange replacementRange;
   BridgedStringRef replacementText;
 };
 
@@ -555,16 +473,8 @@ class BridgedDiagnosticFixIt {
 public:
   int64_t storage[7];
 
-  BridgedDiagnosticFixIt(BridgedSourceLoc start, uint32_t length, BridgedStringRef text);
-};
-
-/// Diagnostic severity when reporting diagnostics.
-enum ENUM_EXTENSIBILITY_ATTR(open) BridgedDiagnosticSeverity : size_t {
-  BridgedFatalError,
-  BridgedError,
-  BridgedWarning,
-  BridgedRemark,
-  BridgedNote,
+  BridgedDiagnosticFixIt(swift::SourceLoc start, uint32_t length,
+                         BridgedStringRef text);
 };
 
 class BridgedDiagnostic {
@@ -585,10 +495,15 @@ class BridgedDiagnostic {
 SWIFT_NAME("BridgedDiagnosticEngine.diagnose(self:at:_:_:highlightAt:"
            "highlightLength:fixIts:)")
 void BridgedDiagnosticEngine_diagnose(
-    BridgedDiagnosticEngine, BridgedSourceLoc loc, BridgedDiagID diagID,
-    BridgedArrayRef arguments, BridgedSourceLoc highlightStart,
+    BridgedDiagnosticEngine, swift::SourceLoc loc, swift::DiagID diagID,
+    BridgedArrayRef arguments, swift::SourceLoc highlightStart,
     uint32_t hightlightLength, BridgedArrayRef fixIts);
 
+SWIFT_NAME("BridgedDiagnosticEngine.getLocationFromExternalSource(self:path:line:column:)")
+swift::SourceLoc BridgedDiagnostic_getLocationFromExternalSource(
+    BridgedDiagnosticEngine bridgedEngine, BridgedStringRef path, SwiftInt line,
+    SwiftInt column);
+
 SWIFT_NAME("getter:BridgedDiagnosticEngine.hadAnyError(self:)")
 bool BridgedDiagnosticEngine_hadAnyError(BridgedDiagnosticEngine);
 
@@ -598,22 +513,22 @@ bool BridgedDiagnosticEngine_hadAnyError(BridgedDiagnosticEngine);
 /// \returns a diagnostic instance that can be extended with additional
 /// information and then must be finished via \c SwiftDiagnostic_finish.
 SWIFT_NAME("BridgedDiagnostic.init(at:message:severity:engine:)")
-BridgedDiagnostic BridgedDiagnostic_create(BridgedSourceLoc cLoc,
+BridgedDiagnostic BridgedDiagnostic_create(swift::SourceLoc loc,
                                            BridgedStringRef cText,
-                                           BridgedDiagnosticSeverity severity,
+                                           swift::DiagnosticKind severity,
                                            BridgedDiagnosticEngine cDiags);
 
 /// Highlight a source range as part of the diagnostic.
 SWIFT_NAME("BridgedDiagnostic.highlight(self:start:end:)")
 void BridgedDiagnostic_highlight(BridgedDiagnostic cDiag,
-                                 BridgedSourceLoc cStartLoc,
-                                 BridgedSourceLoc cEndLoc);
+                                 swift::SourceLoc LStartLoc,
+                                 swift::SourceLoc endLoc);
 
 /// Add a Fix-It to replace a source range as part of the diagnostic.
 SWIFT_NAME("BridgedDiagnostic.fixItReplace(self:start:end:replacement:)")
 void BridgedDiagnostic_fixItReplace(BridgedDiagnostic cDiag,
-                                    BridgedSourceLoc cStartLoc,
-                                    BridgedSourceLoc cEndLoc,
+                                    swift::SourceLoc startLoc,
+                                    swift::SourceLoc endLoc,
                                     BridgedStringRef cReplaceText);
 
 /// Finish the given diagnostic and emit it.
@@ -686,20 +601,14 @@ BridgedClosureExpr_asDeclContext(BridgedClosureExpr cClosure);
 // MARK: Availability
 //===----------------------------------------------------------------------===//
 
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedPlatformKind : size_t {
-  BridgedPlatformKind_None,
-#define AVAILABILITY_PLATFORM(X, PrettyName) BridgedPlatformKind_##X,
-#include "swift/AST/PlatformKinds.def"
-};
-
-SWIFT_NAME("BridgedPlatformKind.init(from:)")
-BridgedPlatformKind BridgedPlatformKind_fromString(BridgedStringRef cStr);
+BRIDGED_OPTIONAL(swift::PlatformKind, PlatformKind)
 
-SWIFT_NAME("BridgedPlatformKind.init(from:)")
-BridgedPlatformKind
-BridgedPlatformKind_fromIdentifier(BridgedIdentifier cIdent);
+SWIFT_NAME("BridgedOptionalPlatformKind.init(from:)")
+BridgedOptionalPlatformKind PlatformKind_fromString(BridgedStringRef cStr);
 
-swift::PlatformKind unbridge(BridgedPlatformKind cPlatform);
+SWIFT_NAME("BridgedOptionalPlatformKind.init(from:)")
+BridgedOptionalPlatformKind
+PlatformKind_fromIdentifier(swift::Identifier ident);
 
 SWIFT_NAME("BridgedAvailabilityMacroMap.has(self:name:)")
 bool BridgedAvailabilityMacroMap_hasName(BridgedAvailabilityMacroMap map,
@@ -736,21 +645,21 @@ BRIDGED_INLINE bool BridgedAvailabilityDomainOrIdentifier_isDomain(
     BridgedAvailabilityDomainOrIdentifier cVal);
 
 SWIFT_NAME("getter:BridgedAvailabilityDomainOrIdentifier.asIdentifier(self:)")
-BRIDGED_INLINE BridgedIdentifier
+BRIDGED_INLINE swift::Identifier
 BridgedAvailabilityDomainOrIdentifier_getAsIdentifier(
     BridgedAvailabilityDomainOrIdentifier cVal);
 
 SWIFT_NAME("BridgedAvailabilitySpec.createWildcard(_:loc:)")
 BridgedAvailabilitySpec
 BridgedAvailabilitySpec_createWildcard(BridgedASTContext cContext,
-                                       BridgedSourceLoc cLoc);
+                                       swift::SourceLoc loc);
 
 SWIFT_NAME(
     "BridgedAvailabilitySpec.createForDomainIdentifier(_:name:nameLoc:version:"
     "versionRange:)")
 BridgedAvailabilitySpec BridgedAvailabilitySpec_createForDomainIdentifier(
-    BridgedASTContext cContext, BridgedIdentifier cName, BridgedSourceLoc cLoc,
-    BridgedVersionTuple cVersion, BridgedSourceRange cVersionRange);
+    BridgedASTContext cContext, swift::Identifier name, swift::SourceLoc loc,
+    BridgedVersionTuple cVersion, swift::SourceRange versionRange);
 
 SWIFT_NAME("BridgedAvailabilitySpec.clone(self:_:)")
 BridgedAvailabilitySpec
@@ -759,14 +668,14 @@ BridgedAvailabilitySpec_clone(BridgedAvailabilitySpec spec,
 
 SWIFT_NAME("BridgedAvailabilitySpec.setMacroLoc(self:_:)")
 void BridgedAvailabilitySpec_setMacroLoc(BridgedAvailabilitySpec spec,
-                                         BridgedSourceLoc cLoc);
+                                         swift::SourceLoc loc);
 
 SWIFT_NAME("getter:BridgedAvailabilitySpec.domainOrIdentifier(self:)")
 BridgedAvailabilityDomainOrIdentifier
 BridgedAvailabilitySpec_getDomainOrIdentifier(BridgedAvailabilitySpec spec);
 
 SWIFT_NAME("getter:BridgedAvailabilitySpec.sourceRange(self:)")
-BridgedSourceRange
+swift::SourceRange
 BridgedAvailabilitySpec_getSourceRange(BridgedAvailabilitySpec spec);
 
 SWIFT_NAME("getter:BridgedAvailabilitySpec.isWildcard(self:)")
@@ -777,7 +686,7 @@ BridgedVersionTuple
 BridgedAvailabilitySpec_getRawVersion(BridgedAvailabilitySpec spec);
 
 SWIFT_NAME("getter:BridgedAvailabilitySpec.versionRange(self:)")
-BridgedSourceRange
+swift::SourceRange
 BridgedAvailabilitySpec_getVersionRange(BridgedAvailabilitySpec spec);
 
 //===----------------------------------------------------------------------===//
@@ -796,37 +705,37 @@ swift::DifferentiabilityKind unbridged(BridgedDifferentiabilityKind cKind);
 
 class BridgedParsedAutoDiffParameter {
 private:
-  BridgedSourceLoc loc;
+  swift::SourceLoc loc;
   enum Kind {
     Named,
     Ordered,
     Self,
   } kind;
   union Value {
-    BridgedIdentifier name;
+    swift::Identifier name;
     unsigned index;
 
-    Value(BridgedIdentifier name) : name(name) {}
+    Value(swift::Identifier name) : name(name) {}
     Value(unsigned index) : index(index) {}
     Value() : name() {}
   } value;
 
-  BridgedParsedAutoDiffParameter(BridgedSourceLoc loc, Kind kind, Value value)
+  BridgedParsedAutoDiffParameter(swift::SourceLoc loc, Kind kind, Value value)
       : loc(loc), kind(kind), value(value) {}
 
 public:
   SWIFT_NAME("forNamed(_:loc:)")
-  static BridgedParsedAutoDiffParameter forNamed(BridgedIdentifier name,
-                                                 BridgedSourceLoc loc) {
+  static BridgedParsedAutoDiffParameter forNamed(swift::Identifier name,
+                                                 swift::SourceLoc loc) {
     return BridgedParsedAutoDiffParameter(loc, Kind::Named, name);
   }
   SWIFT_NAME("forOrdered(_:loc:)")
   static BridgedParsedAutoDiffParameter forOrdered(size_t index,
-                                                   BridgedSourceLoc loc) {
+                                                   swift::SourceLoc loc) {
     return BridgedParsedAutoDiffParameter(loc, Kind::Ordered, index);
   }
   SWIFT_NAME("forSelf(loc:)")
-  static BridgedParsedAutoDiffParameter forSelf(BridgedSourceLoc loc) {
+  static BridgedParsedAutoDiffParameter forSelf(swift::SourceLoc loc) {
     return BridgedParsedAutoDiffParameter(loc, Kind::Self, {});
   }
 
@@ -837,14 +746,11 @@ class BridgedParsedAutoDiffParameter {
 // MARK: DeclAttributes
 //===----------------------------------------------------------------------===//
 
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedDeclAttrKind {
-#define DECL_ATTR(_, CLASS, ...) BridgedDeclAttrKind##CLASS,
-#include "swift/AST/DeclAttr.def"
-  BridgedDeclAttrKindNone,
-};
+BRIDGED_OPTIONAL(swift::DeclAttrKind, DeclAttrKind)
 
-SWIFT_NAME("BridgedDeclAttrKind.init(from:)")
-BridgedDeclAttrKind BridgedDeclAttrKind_fromString(BridgedStringRef cStr);
+SWIFT_NAME("BridgedOptionalDeclAttrKind.init(from:)")
+BridgedOptionalDeclAttrKind
+BridgedOptionalDeclAttrKind_fromString(BridgedStringRef cStr);
 
 struct BridgedDeclAttributes {
   BridgedNullableDeclAttribute chain;
@@ -857,10 +763,10 @@ struct BridgedDeclAttributes {
 };
 
 SWIFT_NAME("BridgedDeclAttribute.shouldBeRejectedByParser(_:)")
-bool BridgedDeclAttribute_shouldBeRejectedByParser(BridgedDeclAttrKind cKind);
+bool BridgedDeclAttribute_shouldBeRejectedByParser(swift::DeclAttrKind kind);
 
 SWIFT_NAME("BridgedDeclAttribute.isDeclModifier(_:)")
-bool BridgedDeclAttribute_isDeclModifier(BridgedDeclAttrKind cKind);
+bool BridgedDeclAttribute_isDeclModifier(swift::DeclAttrKind kind);
 
 SWIFT_NAME("BridgedDeclAttributes.add(self:_:)")
 void BridgedDeclAttributes_add(BridgedDeclAttributes *_Nonnull attrs,
@@ -868,13 +774,13 @@ void BridgedDeclAttributes_add(BridgedDeclAttributes *_Nonnull attrs,
 
 SWIFT_NAME("BridgedDeclAttribute.createSimple(_:kind:atLoc:nameLoc:)")
 BridgedDeclAttribute BridgedDeclAttribute_createSimple(
-    BridgedASTContext cContext, BridgedDeclAttrKind cKind,
-    BridgedSourceLoc cAtLoc, BridgedSourceLoc cNameLoc);
+    BridgedASTContext cContext, swift::DeclAttrKind kind,
+    swift::SourceLoc atLoc, swift::SourceLoc nameLoc);
 
 SWIFT_NAME("BridgedABIAttr.createParsed(_:atLoc:range:abiDecl:)")
 BridgedABIAttr BridgedABIAttr_createParsed(BridgedASTContext cContext,
-                                           BridgedSourceLoc atLoc,
-                                           BridgedSourceRange range,
+                                           swift::SourceLoc atLoc,
+                                           swift::SourceRange range,
                                            BridgedNullableDecl abiDecl);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedAvailableAttrKind {
@@ -888,20 +794,20 @@ SWIFT_NAME("BridgedAvailableAttr.createParsed(_:atLoc:range:domainIdentifier:"
            "domainLoc:kind:message:renamed:introduced:introducedRange:"
            "deprecated:deprecatedRange:obsoleted:obsoletedRange:isSPI:)")
 BridgedAvailableAttr BridgedAvailableAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedIdentifier cDomainIdentifier,
-    BridgedSourceLoc cDomainLoc, BridgedAvailableAttrKind cKind,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, swift::Identifier domainIdentifier,
+    swift::SourceLoc domainLoc, BridgedAvailableAttrKind cKind,
     BridgedStringRef cMessage, BridgedStringRef cRenamed,
-    BridgedVersionTuple cIntroduced, BridgedSourceRange cIntroducedRange,
-    BridgedVersionTuple cDeprecated, BridgedSourceRange cDeprecatedRange,
-    BridgedVersionTuple cObsoleted, BridgedSourceRange cObsoletedRange,
+    BridgedVersionTuple cIntroduced, swift::SourceRange introducedRange,
+    BridgedVersionTuple cDeprecated, swift::SourceRange deprecatedRange,
+    BridgedVersionTuple cObsoleted, swift::SourceRange obsoletedRange,
     bool isSPI);
 
 SWIFT_NAME("BridgedAvailableAttr.createUnavailableInEmbedded(_:atLoc:range:)")
 BridgedAvailableAttr
 BridgedAvailableAttr_createUnavailableInEmbedded(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cAtLoc,
-                                                 BridgedSourceRange cRange);
+                                                 swift::SourceLoc atLoc,
+                                                 swift::SourceRange range);
 
 SWIFT_NAME("BridgedAvailableAttr.setIsGroupMember(self:)")
 void BridgedAvailableAttr_setIsGroupMember(BridgedAvailableAttr cAttr);
@@ -910,126 +816,99 @@ void BridgedAvailableAttr_setIsGroupedWithWildcard(BridgedAvailableAttr cAttr);
 SWIFT_NAME("BridgedAvailableAttr.setIsGroupTerminator(self:)")
 void BridgedAvailableAttr_setIsGroupTerminator(BridgedAvailableAttr cAttr);
 
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedExecutionKind {
-  BridgedExecutionKindConcurrent,
-  BridgedExecutionKindCaller,
-};
-
-SWIFT_NAME("BridgedExecutionAttr.createParsed(_:atLoc:range:behavior:)")
-BridgedExecutionAttr BridgedExecutionAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc atLoc,
-    BridgedSourceRange range, BridgedExecutionKind behavior);
-
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedAccessLevel {
-  BridgedAccessLevelPrivate,
-  BridgedAccessLevelFilePrivate,
-  BridgedAccessLevelInternal,
-  BridgedAccessLevelPackage,
-  BridgedAccessLevelPublic,
-  BridgedAccessLevelOpen,
-  BridgedAccessLevelNone,
-};
+BRIDGED_OPTIONAL(swift::AccessLevel, AccessLevel)
 
 SWIFT_NAME("BridgedAccessControlAttr.createParsed(_:range:accessLevel:)")
 BridgedAccessControlAttr
 BridgedAccessControlAttr_createParsed(BridgedASTContext cContext,
-                                      BridgedSourceRange cRange,
-                                      BridgedAccessLevel cAccessLevel);
+                                      swift::SourceRange range,
+                                      swift::AccessLevel accessLevel);
 
 SWIFT_NAME("BridgedAlignmentAttr.createParsed(_:atLoc:range:value:)")
 BridgedAlignmentAttr
 BridgedAlignmentAttr_createParsed(BridgedASTContext cContext,
-                                  BridgedSourceLoc cAtLoc,
-                                  BridgedSourceRange cRange, size_t cValue);
+                                  swift::SourceLoc atLoc,
+                                  swift::SourceRange range, size_t cValue);
 
 SWIFT_NAME("BridgedAllowFeatureSuppressionAttr.createParsed(_:atLoc:range:inverted:features:)")
 BridgedAllowFeatureSuppressionAttr
-BridgedAllowFeatureSuppressionAttr_createParsed(
-                                  BridgedASTContext cContext,
-                                  BridgedSourceLoc cAtLoc,
-                                  BridgedSourceRange cRange,
-                                  bool inverted,
-                                  BridgedArrayRef cFeatures);
+BridgedAllowFeatureSuppressionAttr_createParsed(BridgedASTContext cContext,
+                                                swift::SourceLoc atLoc,
+                                                swift::SourceRange range,
+                                                bool inverted,
+                                                BridgedArrayRef cFeatures);
 
 SWIFT_NAME(
     "BridgedBackDeployedAttr.createParsed(_:atLoc:range:platform:version:)")
 BridgedBackDeployedAttr BridgedBackDeployedAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedPlatformKind cPlatform,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, swift::PlatformKind platform,
     BridgedVersionTuple cVersion);
 
-SWIFT_NAME("BridgedCDeclAttr.createParsed(_:atLoc:range:name:)")
+SWIFT_NAME("BridgedCDeclAttr.createParsed(_:atLoc:range:name:underscored:)")
 BridgedCDeclAttr BridgedCDeclAttr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAtLoc,
-                                               BridgedSourceRange cRange,
-                                               BridgedStringRef cName);
+                                               swift::SourceLoc atLoc,
+                                               swift::SourceRange range,
+                                               BridgedStringRef cName,
+                                               bool underscored);
 
 SWIFT_NAME(
     "BridgedCustomAttr.createParsed(_:atLoc:type:initContext:argumentList:)")
 BridgedCustomAttr BridgedCustomAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc, BridgedTypeRepr cType,
+    BridgedASTContext cContext, swift::SourceLoc atLoc, BridgedTypeRepr cType,
     BridgedNullableCustomAttributeInitializer cInitContext,
     BridgedNullableArgumentList cArgumentList);
 
 SWIFT_NAME("BridgedDerivativeAttr.createParsed(_:atLoc:range:baseType:"
            "originalName:originalNameLoc:accessorKind:params:)")
 BridgedDerivativeAttr BridgedDerivativeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNullableTypeRepr cBaseType,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedNullableTypeRepr cBaseType,
     BridgedDeclNameRef cOriginalName, BridgedDeclNameLoc cOriginalNameLoc,
-    BridgedAccessorKind cAccessorKind, BridgedArrayRef cParams);
+    swift::AccessorKind AccessorKind, BridgedArrayRef cParams);
 
 SWIFT_NAME("BridgedDerivativeAttr.createParsed(_:atLoc:range:baseType:"
            "originalName:originalNameLoc:params:)")
 BridgedDerivativeAttr BridgedDerivativeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNullableTypeRepr cBaseType,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedNullableTypeRepr cBaseType,
     BridgedDeclNameRef cOriginalName, BridgedDeclNameLoc cOriginalNameLoc,
     BridgedArrayRef cParams);
 
 SWIFT_NAME("BridgedDifferentiableAttr.createParsed(_:atLoc:range:kind:params:"
            "genericWhereClause:)")
 BridgedDifferentiableAttr BridgedDifferentiableAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedDifferentiabilityKind cKind,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedDifferentiabilityKind cKind,
     BridgedArrayRef cParams,
     BridgedNullableTrailingWhereClause cGenericWhereClause);
 
 SWIFT_NAME("BridgedDocumentationAttr.createParsed(_:atLoc:range:metadata:"
            "accessLevel:)")
 BridgedDocumentationAttr BridgedDocumentationAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cMetadata,
-    BridgedAccessLevel cAccessLevel);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedStringRef cMetadata,
+    BridgedOptionalAccessLevel accessLevel);
 
 SWIFT_NAME(
     "BridgedDynamicReplacementAttr.createParsed(_:atLoc:attrNameLoc:lParenLoc:"
     "replacedFunction:rParenLoc:)")
 BridgedDynamicReplacementAttr BridgedDynamicReplacementAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cAttrNameLoc, BridgedSourceLoc cLParenLoc,
-    BridgedDeclNameRef cReplacedFunction, BridgedSourceLoc cRParenLoc);
-
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedEffectsKind {
-  BridgedEffectsKindReadNone,
-  BridgedEffectsKindReadOnly,
-  BridgedEffectsKindReleaseNone,
-  BridgedEffectsKindReadWrite,
-  BridgedEffectsKindUnspecified,
-  BridgedEffectsKindCustom,
-};
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceLoc attrNameLoc, swift::SourceLoc lParenLoc,
+    BridgedDeclNameRef cReplacedFunction, swift::SourceLoc rParenLoc);
 
 SWIFT_NAME("BridgedEffectsAttr.createParsed(_:atLoc:range:effectKind:)")
 BridgedEffectsAttr BridgedEffectsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedEffectsKind cEffectKind);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, swift::EffectsKind effectKind);
 
 SWIFT_NAME("BridgedEffectsAttr.createParsed(_:atLoc:range:customString:"
            "customStringLoc:)")
 BridgedEffectsAttr BridgedEffectsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cCustomString,
-    BridgedSourceLoc cCustomStringLoc);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedStringRef cCustomString,
+    swift::SourceLoc customStringLoc);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedExclusivityAttrMode {
   BridgedExclusivityAttrModeChecked,
@@ -1038,64 +917,50 @@ enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedExclusivityAttrMode {
 
 SWIFT_NAME("BridgedExclusivityAttr.createParsed(_:atLoc:range:mode:)")
 BridgedExclusivityAttr BridgedExclusivityAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedExclusivityAttrMode cMode);
-
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedExposureKind {
-  BridgedExposureKindCxx,
-  BridgedExposureKindWasm,
-};
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedExclusivityAttrMode cMode);
 
 SWIFT_NAME("BridgedExposeAttr.createParsed(_:atLoc:range:name:kind:)")
 BridgedExposeAttr BridgedExposeAttr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cAtLoc,
-                                                 BridgedSourceRange cRange,
+                                                 swift::SourceLoc atLoc,
+                                                 swift::SourceRange range,
                                                  BridgedStringRef cName,
-                                                 BridgedExposureKind cKind);
-
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedExternKind {
-  BridgedExternKindC,
-  BridgedExternKindWasm,
-};
+                                                 swift::ExposureKind kind);
 
 SWIFT_NAME("BridgedExternAttr.createParsed(_:atLoc:range:lParenLoc:rParenLoc:"
            "kind:moduleName:name:)")
 BridgedExternAttr BridgedExternAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedSourceLoc cLParenLoc,
-    BridgedSourceLoc cRParenLoc, BridgedExternKind cKind,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, swift::SourceLoc lParenLoc,
+    swift::SourceLoc rParenLoc, swift::ExternKind kind,
     BridgedStringRef cModuleName, BridgedStringRef cName);
 
 SWIFT_NAME("BridgedImplementsAttr.createParsed(_:atLoc:range:protocolType:"
            "memberName:memberNameLoc:)")
 BridgedImplementsAttr BridgedImplementsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedTypeRepr cProtocolType,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedTypeRepr cProtocolType,
     BridgedDeclNameRef cMemberName, BridgedDeclNameLoc cMemberNameLoc);
 
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedInlineKind {
-  BridgedInlineKindNever,
-  BridgedInlineKindAlways,
-};
-
 SWIFT_NAME("BridgedInlineAttr.createParsed(_:atLoc:range:kind:)")
 BridgedInlineAttr BridgedInlineAttr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cAtLoc,
-                                                 BridgedSourceRange cRange,
-                                                 BridgedInlineKind cKind);
+                                                 swift::SourceLoc atLoc,
+                                                 swift::SourceRange range,
+                                                 swift::InlineKind kind);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedParsedLifetimeDependenceKind {
   BridgedParsedLifetimeDependenceKindDefault,
-  BridgedParsedLifetimeDependenceKindScope,
+  BridgedParsedLifetimeDependenceKindBorrow,
   BridgedParsedLifetimeDependenceKindInherit,
+  BridgedParsedLifetimeDependenceKindInout
 };
 
 class BridgedLifetimeDescriptor {
   union Value {
-    BridgedIdentifier name;
+    swift::Identifier name;
     unsigned index;
 
-    Value(BridgedIdentifier name) : name(name) {}
+    Value(swift::Identifier name) : name(name) {}
     Value(unsigned index) : index(index) {}
     Value() : name() {}
   } value;
@@ -1107,33 +972,33 @@ class BridgedLifetimeDescriptor {
   } kind;
 
   BridgedParsedLifetimeDependenceKind dependenceKind;
-  BridgedSourceLoc loc;
+  swift::SourceLoc loc;
 
   BridgedLifetimeDescriptor(Value value, DescriptorKind kind,
                             BridgedParsedLifetimeDependenceKind dependenceKind,
-                            BridgedSourceLoc loc)
+                            swift::SourceLoc loc)
       : value(value), kind(kind), dependenceKind(dependenceKind), loc(loc) {}
 
 public:
   SWIFT_NAME("forNamed(_:dependenceKind:loc:)")
   static BridgedLifetimeDescriptor
-  forNamed(BridgedIdentifier name,
+  forNamed(swift::Identifier name,
            BridgedParsedLifetimeDependenceKind dependenceKind,
-           BridgedSourceLoc loc) {
+           swift::SourceLoc loc) {
     return BridgedLifetimeDescriptor(name, DescriptorKind::Named,
                                      dependenceKind, loc);
   }
   SWIFT_NAME("forOrdered(_:dependenceKind:loc:)")
   static BridgedLifetimeDescriptor
   forOrdered(size_t index, BridgedParsedLifetimeDependenceKind dependenceKind,
-             BridgedSourceLoc loc) {
+             swift::SourceLoc loc) {
     return BridgedLifetimeDescriptor(index, DescriptorKind::Ordered,
                                      dependenceKind, loc);
   }
   SWIFT_NAME("forSelf(dependenceKind:loc:)")
   static BridgedLifetimeDescriptor
   forSelf(BridgedParsedLifetimeDependenceKind dependenceKind,
-          BridgedSourceLoc loc) {
+          swift::SourceLoc loc) {
     return BridgedLifetimeDescriptor({}, DescriptorKind::Self, dependenceKind,
                                      loc);
   }
@@ -1144,18 +1009,19 @@ class BridgedLifetimeDescriptor {
 SWIFT_NAME("BridgedLifetimeEntry.createParsed(_:range:sources:)")
 BridgedLifetimeEntry
 BridgedLifetimeEntry_createParsed(BridgedASTContext cContext,
-                                  BridgedSourceRange cRange,
+                                  swift::SourceRange range,
                                   BridgedArrayRef cSources);
 
 SWIFT_NAME("BridgedLifetimeEntry.createParsed(_:range:sources:target:)")
 BridgedLifetimeEntry BridgedLifetimeEntry_createParsed(
-    BridgedASTContext cContext, BridgedSourceRange cRange,
+    BridgedASTContext cContext, swift::SourceRange range,
     BridgedArrayRef cSources, BridgedLifetimeDescriptor cTarget);
 
-SWIFT_NAME("BridgedLifetimeAttr.createParsed(_:atLoc:range:entry:)")
+SWIFT_NAME(
+    "BridgedLifetimeAttr.createParsed(_:atLoc:range:entry:isUnderscored:)")
 BridgedLifetimeAttr BridgedLifetimeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedLifetimeEntry cEntry);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedLifetimeEntry cEntry, bool isUnderscored);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedMacroSyntax {
   BridgedMacroSyntaxFreestanding,
@@ -1197,32 +1063,32 @@ BRIDGED_INLINE bool BridgedMacroRole_isAttached(BridgedMacroRole role);
 SWIFT_NAME("BridgedMacroRoleAttr.createParsed(_:atLoc:range:syntax:lParenLoc:"
            "role:names:conformances:rParenLoc:)")
 BridgedMacroRoleAttr BridgedMacroRoleAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedMacroSyntax cSyntax,
-    BridgedSourceLoc cLParenLoc, BridgedMacroRole cRole, BridgedArrayRef cNames,
-    BridgedArrayRef cConformances, BridgedSourceLoc cRParenLoc);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedMacroSyntax cSyntax,
+    swift::SourceLoc lParenLoc, BridgedMacroRole cRole, BridgedArrayRef cNames,
+    BridgedArrayRef cConformances, swift::SourceLoc rParenLoc);
 
 SWIFT_NAME("BridgedOriginallyDefinedInAttr.createParsed(_:atLoc:range:"
            "moduleName:platform:version:)")
 BridgedOriginallyDefinedInAttr BridgedOriginallyDefinedInAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cModuleName,
-    BridgedPlatformKind cPlatform, BridgedVersionTuple cVersion);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedStringRef cModuleName,
+    swift::PlatformKind platform, BridgedVersionTuple cVersion);
 
 SWIFT_NAME("BridgedStorageRestrictionsAttr.createParsed(_:atLoc:range:"
            "initializes:accesses:)")
 BridgedStorageRestrictionsAttr BridgedStorageRestrictionsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedArrayRef cInitializes,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedArrayRef cInitializes,
     BridgedArrayRef cAccesses);
 
 SWIFT_NAME(
     "BridgedSwiftNativeObjCRuntimeBaseAttr.createParsed(_:atLoc:range:name:)")
 BridgedSwiftNativeObjCRuntimeBaseAttr
 BridgedSwiftNativeObjCRuntimeBaseAttr_createParsed(BridgedASTContext cContext,
-                                                   BridgedSourceLoc cAtLoc,
-                                                   BridgedSourceRange cRange,
-                                                   BridgedIdentifier cName);
+                                                   swift::SourceLoc atLoc,
+                                                   swift::SourceRange range,
+                                                   swift::Identifier name);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedNonSendableKind {
   BridgedNonSendableKindSpecific,
@@ -1231,46 +1097,50 @@ enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedNonSendableKind {
 
 SWIFT_NAME("BridgedNonSendableAttr.createParsed(_:atLoc:range:kind:)")
 BridgedNonSendableAttr BridgedNonSendableAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNonSendableKind cKind);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedNonSendableKind cKind);
+
+SWIFT_NAME("BridgedNonisolatedAttr.createParsed(_:atLoc:range:modifier:)")
+BridgedNonisolatedAttr BridgedNonisolatedAttr_createParsed(
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, swift::NonIsolatedModifier modifier);
 
-SWIFT_NAME("BridgedNonisolatedAttr.createParsed(_:atLoc:range:isUnsafe:)")
-BridgedNonisolatedAttr
-BridgedNonisolatedAttr_createParsed(BridgedASTContext cContext,
-                                    BridgedSourceLoc cAtLoc,
-                                    BridgedSourceRange cRange, bool isUnsafe);
+SWIFT_NAME("BridgedInheritActorContextAttr.createParsed(_:atLoc:range:modifier:)")
+BridgedInheritActorContextAttr BridgedInheritActorContextAttr_createParsed(
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, swift::InheritActorContextModifier modifier);
 
 SWIFT_NAME("BridgedObjCAttr.createParsedUnnamed(_:atLoc:attrNameLoc:)")
 BridgedObjCAttr
 BridgedObjCAttr_createParsedUnnamed(BridgedASTContext cContext,
-                                    BridgedSourceLoc cAtLoc,
-                                    BridgedSourceLoc cAttrNameLoc);
+                                    swift::SourceLoc atLoc,
+                                    swift::SourceLoc attrNameLoc);
 
 SWIFT_NAME("BridgedObjCAttr.createParsedNullary(_:atLoc:attrNameLoc:lParenLoc:"
            "nameLoc:name:rParenLoc:)")
 BridgedObjCAttr BridgedObjCAttr_createParsedNullary(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cAttrNameLoc, BridgedSourceLoc cLParenLoc,
-    BridgedSourceLoc cNameLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cRParenLoc);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceLoc attrNameLoc, swift::SourceLoc lParenLoc,
+    swift::SourceLoc nameLoc, swift::Identifier name,
+    swift::SourceLoc rParenLoc);
 
 SWIFT_NAME("BridgedObjCAttr.createParsedSelector(_:atLoc:attrNameLoc:lParenLoc:"
            "nameLocs:names:rParenLoc:)")
 BridgedObjCAttr BridgedObjCAttr_createParsedSelector(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cAttrNameLoc, BridgedSourceLoc cLParenLoc,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceLoc attrNameLoc, swift::SourceLoc lParenLoc,
     BridgedArrayRef cNameLocs, BridgedArrayRef cNames,
-    BridgedSourceLoc cRParenLoc);
+    swift::SourceLoc rParenLoc);
 
 SWIFT_NAME("BridgedObjCImplementationAttr.createParsed(_:atLoc:range:name:isEarlyAdopter:)")
 BridgedObjCImplementationAttr BridgedObjCImplementationAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedIdentifier cName, bool isEarlyAdopter);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, swift::Identifier name, bool isEarlyAdopter);
 
 SWIFT_NAME("BridgedObjCRuntimeNameAttr.createParsed(_:atLoc:range:name:)")
 BridgedObjCRuntimeNameAttr BridgedObjCRuntimeNameAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedIdentifier cName);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, swift::Identifier name);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedOptimizationMode {
   BridgedOptimizationModeForSpeed,
@@ -1280,44 +1150,44 @@ enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedOptimizationMode {
 
 SWIFT_NAME("BridgedOptimizeAttr.createParsed(_:atLoc:range:mode:)")
 BridgedOptimizeAttr BridgedOptimizeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedOptimizationMode cMode);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedOptimizationMode cMode);
 
 SWIFT_NAME("BridgedPrivateImportAttr.createParsed(_:atLoc:attrNameLoc:"
            "lParenLoc:fileName:rParenLoc:)")
 BridgedPrivateImportAttr BridgedPrivateImportAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cAttrNameLoc, BridgedSourceLoc cLParenLoc,
-    BridgedStringRef cFileName, BridgedSourceLoc cRParenLoc);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceLoc attrNameLoc, swift::SourceLoc lParenLoc,
+    BridgedStringRef cFileName, swift::SourceLoc rParenLoc);
 
 SWIFT_NAME(
     "BridgedProjectedValuePropertyAttr.createParsed(_:atLoc:range:name:)")
 BridgedProjectedValuePropertyAttr
 BridgedProjectedValuePropertyAttr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAtLoc,
-                                               BridgedSourceRange cRange,
-                                               BridgedIdentifier cName);
+                                               swift::SourceLoc atLoc,
+                                               swift::SourceRange range,
+                                               swift::Identifier name);
 
 SWIFT_NAME("BridgedRawDocCommentAttr.createParsed(_:range:)")
 BridgedRawDocCommentAttr
 BridgedRawDocCommentAttr_createParsed(BridgedASTContext cContext,
-                                      BridgedCharSourceRange cRange);
+                                      swift::CharSourceRange range);
 
 SWIFT_NAME("BridgedRawLayoutAttr.createParsed(_:atLoc:range:size:alignment:)")
 BridgedRawLayoutAttr BridgedStorageRestrictionsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, size_t size, size_t alignment);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, size_t size, size_t alignment);
 
 SWIFT_NAME("BridgedRawLayoutAttr.createParsed(_:atLoc:range:like:moveAsLike:)")
 BridgedRawLayoutAttr BridgedStorageRestrictionsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedTypeRepr cLikeType, bool moveAsLike);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedTypeRepr cLikeType, bool moveAsLike);
 
 SWIFT_NAME("BridgedRawLayoutAttr.createParsed(_:atLoc:range:likeArrayOf:count:"
            "moveAsLike:)")
 BridgedRawLayoutAttr BridgedStorageRestrictionsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedTypeRepr cLikeType,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedTypeRepr cLikeType,
     BridgedTypeRepr cCountType, bool moveAsLike);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedReferenceOwnership {
@@ -1331,25 +1201,25 @@ swift::ReferenceOwnership unbridged(BridgedReferenceOwnership kind);
 
 SWIFT_NAME("BridgedReferenceOwnershipAttr.createParsed(_:atLoc:range:kind:)")
 BridgedReferenceOwnershipAttr BridgedReferenceOwnershipAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedReferenceOwnership cKind);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedReferenceOwnership cKind);
 
 SWIFT_NAME("BridgedSectionAttr.createParsed(_:atLoc:range:name:)")
 BridgedSectionAttr BridgedSectionAttr_createParsed(BridgedASTContext cContext,
-                                                   BridgedSourceLoc cAtLoc,
-                                                   BridgedSourceRange cRange,
+                                                   swift::SourceLoc atLoc,
+                                                   swift::SourceRange range,
                                                    BridgedStringRef cName);
 
 SWIFT_NAME("BridgedSemanticsAttr.createParsed(_:atLoc:range:value:)")
 BridgedSemanticsAttr BridgedSemanticsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cValue);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedStringRef cValue);
 
 SWIFT_NAME("BridgedSetterAccessAttr.createParsed(_:range:accessLevel:)")
 BridgedSetterAccessAttr
 BridgedSetterAccessAttr_createParsed(BridgedASTContext cContext,
-                                     BridgedSourceRange cRange,
-                                     BridgedAccessLevel cAccessLevel);
+                                     swift::SourceRange range,
+                                     swift::AccessLevel accessLevel);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedSpecializationKind : uint8_t {
   BridgedSpecializationKindFull,
@@ -1359,8 +1229,17 @@ enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedSpecializationKind : uint8_t {
 SWIFT_NAME("BridgedSpecializeAttr.createParsed(_:atLoc:range:whereClause:"
            "exported:kind:taretFunction:spiGroups:availableAttrs:)")
 BridgedSpecializeAttr BridgedSpecializeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNullableTrailingWhereClause cWhereClause,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedNullableTrailingWhereClause cWhereClause,
+    bool exported, BridgedSpecializationKind cKind,
+    BridgedDeclNameRef cTargetFunction, BridgedArrayRef cSPIGroups,
+    BridgedArrayRef cAvailableAttrs);
+
+SWIFT_NAME("BridgedSpecializedAttr.createParsed(_:atLoc:range:whereClause:"
+           "exported:kind:taretFunction:spiGroups:availableAttrs:)")
+BridgedSpecializedAttr BridgedSpecializedAttr_createParsed(
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedNullableTrailingWhereClause cWhereClause,
     bool exported, BridgedSpecializationKind cKind,
     BridgedDeclNameRef cTargetFunction, BridgedArrayRef cSPIGroups,
     BridgedArrayRef cAvailableAttrs);
@@ -1368,33 +1247,33 @@ BridgedSpecializeAttr BridgedSpecializeAttr_createParsed(
 SWIFT_NAME(
     "BridgedSPIAccessControlAttr.createParsed(_:atLoc:range:spiGroupName:)")
 BridgedSPIAccessControlAttr BridgedSPIAccessControlAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedIdentifier cSPIGroupName);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, swift::Identifier SPIGroupName);
 
 SWIFT_NAME("BridgedSILGenNameAttr.createParsed(_:atLoc:range:name:isRaw:)")
 BridgedSILGenNameAttr BridgedSILGenNameAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cName, bool isRaw);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedStringRef cName, bool isRaw);
 
 SWIFT_NAME(
     "BridgedTransposeAttr.createParsed(_:atLoc:range:baseType:originalName:"
     "originalNameLoc:params:)")
 BridgedTransposeAttr BridgedTransposeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNullableTypeRepr cBaseType,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedNullableTypeRepr cBaseType,
     BridgedDeclNameRef cOriginalName, BridgedDeclNameLoc cOriginalNameLoc,
     BridgedArrayRef cParams);
 
 SWIFT_NAME("BridgedTypeEraserAttr.createParsed(_:atLoc:range:typeExpr:)")
 BridgedTypeEraserAttr BridgedTypeEraserAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedTypeExpr cTypeExpr);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedTypeExpr cTypeExpr);
 
 SWIFT_NAME(
     "BridgedUnavailableFromAsyncAttr.createParsed(_:atLoc:range:message:)")
 BridgedUnavailableFromAsyncAttr BridgedUnavailableFromAsyncAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cMessage);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceRange range, BridgedStringRef cMessage);
 
 //===----------------------------------------------------------------------===//
 // MARK: Decls
@@ -1416,9 +1295,9 @@ enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedStaticSpelling {
 };
 
 struct BridgedAccessorRecord {
-  BridgedSourceLoc lBraceLoc;
+  swift::SourceLoc lBraceLoc;
   BridgedArrayRef accessors;
-  BridgedSourceLoc rBraceLoc;
+  swift::SourceLoc rBraceLoc;
 };
 
 SWIFT_NAME("BridgedAccessorDecl.createParsed(_:declContext:kind:storage:"
@@ -1426,10 +1305,10 @@ SWIFT_NAME("BridgedAccessorDecl.createParsed(_:declContext:kind:storage:"
            "throwsSpecifierLoc:thrownType:)")
 BridgedAccessorDecl BridgedAccessorDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedAccessorKind cKind, BridgedAbstractStorageDecl cStorage,
-    BridgedSourceLoc cDeclLoc, BridgedSourceLoc cAccessorKeywordLoc,
-    BridgedNullableParameterList cParamList, BridgedSourceLoc cAsyncLoc,
-    BridgedSourceLoc cThrowsLoc, BridgedNullableTypeRepr cThrownType);
+    swift::AccessorKind Kind, BridgedAbstractStorageDecl cStorage,
+    swift::SourceLoc declLoc, swift::SourceLoc accessorKeywordLoc,
+    BridgedNullableParameterList cParamList, swift::SourceLoc asyncLoc,
+    swift::SourceLoc throwsLoc, BridgedNullableTypeRepr cThrownType);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedVarDeclIntroducer {
   BridgedVarDeclIntroducerLet = 0,
@@ -1442,8 +1321,8 @@ SWIFT_NAME("BridgedPatternBindingDecl.createParsed(_:declContext:attributes:"
            "staticLoc:staticSpelling:introducerLoc:introducer:entries:)")
 BridgedPatternBindingDecl BridgedPatternBindingDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedDeclAttributes cAttrs, BridgedSourceLoc cStaticLoc,
-    BridgedStaticSpelling cStaticSpelling, BridgedSourceLoc cIntroducerLoc,
+    BridgedDeclAttributes cAttrs, swift::SourceLoc staticLoc,
+    BridgedStaticSpelling cStaticSpelling, swift::SourceLoc introducerLoc,
     BridgedVarDeclIntroducer cIntorducer, BridgedArrayRef cBindingEntries);
 
 SWIFT_NAME("BridgedParamDecl.createParsed(_:declContext:specifierLoc:argName:"
@@ -1451,9 +1330,9 @@ SWIFT_NAME("BridgedParamDecl.createParsed(_:declContext:specifierLoc:argName:"
            "defaultValueInitContext:)")
 BridgedParamDecl BridgedParamDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cSpecifierLoc, BridgedIdentifier cArgName,
-    BridgedSourceLoc cArgNameLoc, BridgedIdentifier cParamName,
-    BridgedSourceLoc cParamNameLoc, BridgedNullableExpr defaultValue,
+    swift::SourceLoc specifierLoc, swift::Identifier argName,
+    swift::SourceLoc argNameLoc, swift::Identifier paramName,
+    swift::SourceLoc paramNameLoc, BridgedNullableExpr defaultValue,
     BridgedNullableDefaultArgumentInitializer cDefaultArgumentInitContext);
 
 SWIFT_NAME("BridgedParamDecl.setTypeRepr(self:_:)")
@@ -1498,11 +1377,11 @@ SWIFT_NAME("BridgedFuncDecl.createParsed(_:declContext:staticLoc:"
            "throwsSpecifierLoc:thrownType:returnType:genericWhereClause:)")
 BridgedFuncDecl BridgedFuncDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cStaticLoc, BridgedStaticSpelling cStaticSpelling,
-    BridgedSourceLoc cFuncKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
-    BridgedParameterList parameterList, BridgedSourceLoc cAsyncLoc,
-    BridgedSourceLoc cThrowsLoc, BridgedNullableTypeRepr thrownType,
+    swift::SourceLoc staticLoc, BridgedStaticSpelling cStaticSpelling,
+    swift::SourceLoc funcKeywordLoc, swift::Identifier name,
+    swift::SourceLoc nameLoc, BridgedNullableGenericParamList genericParamList,
+    BridgedParameterList parameterList, swift::SourceLoc asyncLoc,
+    swift::SourceLoc throwsLoc, BridgedNullableTypeRepr thrownType,
     BridgedNullableTypeRepr returnType,
     BridgedNullableTrailingWhereClause opaqueGenericWhereClause);
 
@@ -1512,10 +1391,10 @@ SWIFT_NAME(
     "asyncSpecifierLoc:throwsSpecifierLoc:thrownType:genericWhereClause:)")
 BridgedConstructorDecl BridgedConstructorDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cInitKeywordLoc, BridgedSourceLoc cFailabilityMarkLoc,
+    swift::SourceLoc initKeywordLoc, swift::SourceLoc failabilityMarkLoc,
     bool isIUO, BridgedNullableGenericParamList genericParams,
-    BridgedParameterList parameterList, BridgedSourceLoc cAsyncLoc,
-    BridgedSourceLoc cThrowsLoc, BridgedNullableTypeRepr thrownType,
+    BridgedParameterList parameterList, swift::SourceLoc asyncLoc,
+    swift::SourceLoc throwsLoc, BridgedNullableTypeRepr thrownType,
     BridgedNullableTrailingWhereClause genericWhereClause);
 
 SWIFT_NAME(
@@ -1523,16 +1402,16 @@ SWIFT_NAME(
 BridgedDestructorDecl
 BridgedDestructorDecl_createParsed(BridgedASTContext cContext,
                                    BridgedDeclContext cDeclContext,
-                                   BridgedSourceLoc cDeinitKeywordLoc);
+                                   swift::SourceLoc deinitKeywordLoc);
 
 SWIFT_NAME(
     "BridgedTypeAliasDecl.createParsed(_:declContext:typealiasKeywordLoc:name:"
     "nameLoc:genericParamList:equalLoc:underlyingType:genericWhereClause:)")
 BridgedTypeAliasDecl BridgedTypeAliasDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cAliasKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
-    BridgedSourceLoc cEqualLoc, BridgedTypeRepr underlyingType,
+    swift::SourceLoc aliasKeywordLoc, swift::Identifier name,
+    swift::SourceLoc nameLoc, BridgedNullableGenericParamList genericParamList,
+    swift::SourceLoc equalLoc, BridgedTypeRepr underlyingType,
     BridgedNullableTrailingWhereClause genericWhereClause);
 
 SWIFT_NAME("BridgedExtensionDecl.setParsedMembers(self:_:fingerprint:)")
@@ -1545,25 +1424,25 @@ SWIFT_NAME(
     "genericParamList:inheritedTypes:genericWhereClause:braceRange:)")
 BridgedNominalTypeDecl BridgedEnumDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cEnumKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
+    swift::SourceLoc enumKeywordLoc, swift::Identifier name,
+    swift::SourceLoc nameLoc, BridgedNullableGenericParamList genericParamList,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange);
+    swift::SourceRange braceRange);
 
 SWIFT_NAME(
     "BridgedEnumCaseDecl.createParsed(declContext:caseKeywordLoc:elements:)")
 BridgedEnumCaseDecl
 BridgedEnumCaseDecl_createParsed(BridgedDeclContext cDeclContext,
-                                 BridgedSourceLoc cCaseKeywordLoc,
+                                 swift::SourceLoc caseKeywordLoc,
                                  BridgedArrayRef cElements);
 
 SWIFT_NAME("BridgedEnumElementDecl.createParsed(_:declContext:name:nameLoc:"
            "parameterList:equalsLoc:rawValue:)")
 BridgedEnumElementDecl BridgedEnumElementDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedIdentifier cName, BridgedSourceLoc cNameLoc,
-    BridgedNullableParameterList parameterList, BridgedSourceLoc cEqualsLoc,
+    swift::Identifier name, swift::SourceLoc nameLoc,
+    BridgedNullableParameterList parameterList, swift::SourceLoc equalsLoc,
     BridgedNullableExpr opaqueRawValue);
 
 SWIFT_NAME("BridgedStructDecl.createParsed(_:declContext:structKeywordLoc:name:"
@@ -1571,22 +1450,22 @@ SWIFT_NAME("BridgedStructDecl.createParsed(_:declContext:structKeywordLoc:name:"
            "braceRange:)")
 BridgedNominalTypeDecl BridgedStructDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cStructKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
+    swift::SourceLoc structKeywordLoc, swift::Identifier name,
+    swift::SourceLoc nameLoc, BridgedNullableGenericParamList genericParamList,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange);
+    swift::SourceRange braceRange);
 
 SWIFT_NAME(
     "BridgedClassDecl.createParsed(_:declContext:classKeywordLoc:name:nameLoc:"
     "genericParamList:inheritedTypes:genericWhereClause:braceRange:isActor:)")
 BridgedNominalTypeDecl BridgedClassDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cClassKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
+    swift::SourceLoc classKeywordLoc, swift::Identifier name,
+    swift::SourceLoc nameLoc, BridgedNullableGenericParamList genericParamList,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange, bool isActor);
+    swift::SourceRange braceRange, bool isActor);
 
 SWIFT_NAME(
     "BridgedProtocolDecl.createParsed(_:declContext:protocolKeywordLoc:name:"
@@ -1594,19 +1473,19 @@ SWIFT_NAME(
     "genericWhereClause:braceRange:)")
 BridgedNominalTypeDecl BridgedProtocolDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cProtocolKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedArrayRef cPrimaryAssociatedTypeNames,
+    swift::SourceLoc protocolKeywordLoc, swift::Identifier name,
+    swift::SourceLoc nameLoc, BridgedArrayRef cPrimaryAssociatedTypeNames,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange);
+    swift::SourceRange braceRange);
 
 SWIFT_NAME("BridgedAssociatedTypeDecl.createParsed(_:declContext:"
            "associatedtypeKeywordLoc:name:nameLoc:inheritedTypes:defaultType:"
            "genericWhereClause:)")
 BridgedAssociatedTypeDecl BridgedAssociatedTypeDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cAssociatedtypeKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedArrayRef cInheritedTypes,
+    swift::SourceLoc associatedtypeKeywordLoc, swift::Identifier name,
+    swift::SourceLoc nameLoc, BridgedArrayRef cInheritedTypes,
     BridgedNullableTypeRepr opaqueDefaultType,
     BridgedNullableTrailingWhereClause genericWhereClause);
 
@@ -1616,29 +1495,29 @@ SWIFT_NAME(
     "genericWhereClause:)")
 BridgedMacroDecl BridgedMacroDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cMacroLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList cGenericParams,
-    BridgedParameterList cParams, BridgedSourceLoc cArrowLoc,
+    swift::SourceLoc macroLoc, swift::Identifier name, swift::SourceLoc nameLoc,
+    BridgedNullableGenericParamList cGenericParams,
+    BridgedParameterList cParams, swift::SourceLoc arrowLoc,
     BridgedNullableTypeRepr cResultType, BridgedNullableExpr cDefinition,
     BridgedNullableTrailingWhereClause genericWhereClause);
 
 SWIFT_NAME("BridgedMacroExpansionDecl.createParsed(_:poundLoc:macroNameRef:"
            "macroNameLoc:leftAngleLoc:genericArgs:rightAngleLoc:args:)")
 BridgedMacroExpansionDecl BridgedMacroExpansionDecl_createParsed(
-    BridgedDeclContext cDeclContext, BridgedSourceLoc cPoundLoc,
+    BridgedDeclContext cDeclContext, swift::SourceLoc poundLoc,
     BridgedDeclNameRef cMacroNameRef, BridgedDeclNameLoc cMacroNameLoc,
-    BridgedSourceLoc cLeftAngleLoc, BridgedArrayRef cGenericArgs,
-    BridgedSourceLoc cRightAngleLoc, BridgedNullableArgumentList cArgList);
+    swift::SourceLoc leftAngleLoc, BridgedArrayRef cGenericArgs,
+    swift::SourceLoc rightAngleLoc, BridgedNullableArgumentList cArgList);
 
 SWIFT_NAME(
     "BridgedExtensionDecl.createParsed(_:declContext:extensionKeywordLoc:"
     "extendedType:inheritedTypes:genericWhereClause:braceRange:)")
 BridgedExtensionDecl BridgedExtensionDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cExtensionKeywordLoc, BridgedTypeRepr opaqueExtendedType,
+    swift::SourceLoc extensionKeywordLoc, BridgedTypeRepr opaqueExtendedType,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange);
+    swift::SourceRange braceRange);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedOperatorFixity {
   BridgedOperatorFixityInfix,
@@ -1649,23 +1528,16 @@ enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedOperatorFixity {
 SWIFT_NAME("BridgedMissingDecl.create(_:declContext:loc:)")
 BridgedMissingDecl BridgedMissingDecl_create(BridgedASTContext cContext,
                                              BridgedDeclContext cDeclContext,
-                                             BridgedSourceLoc cLoc);
+                                             swift::SourceLoc loc);
 
 SWIFT_NAME("BridgedOperatorDecl.createParsed(_:declContext:fixity:"
            "operatorKeywordLoc:name:nameLoc:colonLoc:precedenceGroupName:"
            "precedenceGroupLoc:)")
 BridgedOperatorDecl BridgedOperatorDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedOperatorFixity cFixity, BridgedSourceLoc cOperatorKeywordLoc,
-    BridgedIdentifier cName, BridgedSourceLoc cNameLoc,
-    BridgedSourceLoc cColonLoc, BridgedIdentifier cPrecedenceGroupName,
-    BridgedSourceLoc cPrecedenceGroupLoc);
-
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedAssociativity {
-  BridgedAssociativityNone,
-  BridgedAssociativityLeft,
-  BridgedAssociativityRight,
-};
+    BridgedOperatorFixity cFixity, swift::SourceLoc operatorKeywordLoc,
+    swift::Identifier name, swift::SourceLoc nameLoc, swift::SourceLoc colonLoc,
+    swift::Identifier precedenceGroupName, swift::SourceLoc precedenceGroupLoc);
 
 SWIFT_NAME("BridgedPrecedenceGroupDecl.createParsed(declContext:"
            "precedencegroupKeywordLoc:name:nameLoc:leftBraceLoc:"
@@ -1674,16 +1546,14 @@ SWIFT_NAME("BridgedPrecedenceGroupDecl.createParsed(declContext:"
            "higherThanKeywordLoc:higherThanNames:lowerThanKeywordLoc:"
            "lowerThanNames:rightBraceLoc:)")
 BridgedPrecedenceGroupDecl BridgedPrecedenceGroupDecl_createParsed(
-    BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cPrecedencegroupKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedSourceLoc cLeftBraceLoc,
-    BridgedSourceLoc cAssociativityKeywordLoc,
-    BridgedSourceLoc cAssociativityValueLoc,
-    BridgedAssociativity cAssociativity, BridgedSourceLoc cAssignmentKeywordLoc,
-    BridgedSourceLoc cAssignmentValueLoc, bool isAssignment,
-    BridgedSourceLoc cHigherThanKeywordLoc, BridgedArrayRef cHigherThanNames,
-    BridgedSourceLoc cLowerThanKeywordLoc, BridgedArrayRef cLowerThanNames,
-    BridgedSourceLoc cRightBraceLoc);
+    BridgedDeclContext cDeclContext, swift::SourceLoc precedencegroupKeywordLoc,
+    swift::Identifier name, swift::SourceLoc nameLoc,
+    swift::SourceLoc leftBraceLoc, swift::SourceLoc associativityKeywordLoc,
+    swift::SourceLoc associativityValueLoc, swift::Associativity associativity,
+    swift::SourceLoc assignmentKeywordLoc, swift::SourceLoc assignmentValueLoc,
+    bool isAssignment, swift::SourceLoc higherThanKeywordLoc,
+    BridgedArrayRef cHigherThanNames, swift::SourceLoc lowerThanKeywordLoc,
+    BridgedArrayRef cLowerThanNames, swift::SourceLoc rightBraceLoc);
 
 enum ENUM_EXTENSIBILITY_ATTR(open) BridgedImportKind {
   BridgedImportKindModule,
@@ -1700,18 +1570,31 @@ SWIFT_NAME("BridgedImportDecl.createParsed(_:declContext:importKeywordLoc:"
            "importKind:importKindLoc:path:)")
 BridgedImportDecl BridgedImportDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cImportKeywordLoc, BridgedImportKind cImportKind,
-    BridgedSourceLoc cImportKindLoc, BridgedArrayRef cImportPathElements);
+    swift::SourceLoc importKeywordLoc, BridgedImportKind cImportKind,
+    swift::SourceLoc importKindLoc, BridgedArrayRef cImportPathElements);
+
+enum ENUM_EXTENSIBILITY_ATTR(open) BridgedUsingSpecifier {
+  BridgedUsingSpecifierMainActor,
+  BridgedUsingSpecifierNonisolated,
+};
+
+SWIFT_NAME("BridgedUsingDecl.createParsed(_:declContext:usingKeywordLoc:"
+           "specifierLoc:specifier:)")
+BridgedUsingDecl BridgedUsingDecl_createParsed(BridgedASTContext cContext,
+                                               BridgedDeclContext cDeclContext,
+                                               swift::SourceLoc usingKeywordLoc,
+                                               swift::SourceLoc specifierLoc,
+                                               BridgedUsingSpecifier specifier);
 
 SWIFT_NAME("BridgedSubscriptDecl.createParsed(_:declContext:staticLoc:"
            "staticSpelling:subscriptKeywordLoc:genericParamList:parameterList:"
            "arrowLoc:returnType:genericWhereClause:)")
 BridgedSubscriptDecl BridgedSubscriptDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cStaticLoc, BridgedStaticSpelling cStaticSpelling,
-    BridgedSourceLoc cSubscriptKeywordLoc,
+    swift::SourceLoc staticLoc, BridgedStaticSpelling cStaticSpelling,
+    swift::SourceLoc subscriptKeywordLoc,
     BridgedNullableGenericParamList cGenericParamList,
-    BridgedParameterList cParamList, BridgedSourceLoc cArrowLoc,
+    BridgedParameterList cParamList, swift::SourceLoc arrowLoc,
     BridgedTypeRepr returnType,
     BridgedNullableTrailingWhereClause genericWhereClause);
 
@@ -1776,7 +1659,8 @@ void BridgedNominalTypeDecl_setParsedMembers(BridgedNominalTypeDecl decl,
                                              BridgedFingerprint fingerprint);
 
 SWIFT_NAME("BridgedNominalTypeDecl.getSourceLocation(self:)")
-BRIDGED_INLINE BridgedSourceLoc BridgedNominalTypeDecl_getSourceLocation(BridgedNominalTypeDecl decl);
+BRIDGED_INLINE swift::SourceLoc
+BridgedNominalTypeDecl_getSourceLocation(BridgedNominalTypeDecl decl);
 
 //===----------------------------------------------------------------------===//
 // MARK: SubscriptDecl
@@ -1805,8 +1689,8 @@ BridgedVarDecl_asAbstractStorageDecl(BridgedVarDecl decl);
 //===----------------------------------------------------------------------===//
 
 struct BridgedCallArgument {
-  BridgedSourceLoc labelLoc;
-  BridgedIdentifier label;
+  swift::SourceLoc labelLoc;
+  swift::Identifier label;
   BridgedExpr argExpr;
 
   BRIDGED_INLINE swift::Argument unbridged() const;
@@ -1820,49 +1704,49 @@ BridgedArgumentList_createImplicitUnlabeled(BridgedASTContext cContext,
 SWIFT_NAME("BridgedArgumentList.createParsed(_:lParenLoc:args:rParenLoc:"
            "firstTrailingClosureIndex:)")
 BridgedArgumentList BridgedArgumentList_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLParenLoc,
-    BridgedArrayRef cArgs, BridgedSourceLoc cRParenLoc,
+    BridgedASTContext cContext, swift::SourceLoc lParenLoc,
+    BridgedArrayRef cArgs, swift::SourceLoc rParenLoc,
     size_t cFirstTrailingClosureIndex);
 
 SWIFT_NAME("BridgedArrayExpr.createParsed(_:lSquareLoc:elements:commaLocs:"
            "rSquareLoc:)")
 BridgedArrayExpr BridgedArrayExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cLLoc,
+                                               swift::SourceLoc lLoc,
                                                BridgedArrayRef elements,
                                                BridgedArrayRef commas,
-                                               BridgedSourceLoc cRLoc);
+                                               swift::SourceLoc rLoc);
 
 SWIFT_NAME(
     "BridgedArrowExpr.createParsed(_:asyncLoc:throwsLoc:thrownType:arrowLoc:)")
 BridgedArrowExpr BridgedArrowExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAsyncLoc,
-                                               BridgedSourceLoc cThrowsLoc,
+                                               swift::SourceLoc asyncLoc,
+                                               swift::SourceLoc throwsLoc,
                                                BridgedNullableExpr cThrownType,
-                                               BridgedSourceLoc cArrowLoc);
+                                               swift::SourceLoc arrowLoc);
 
 SWIFT_NAME("BridgedAssignExpr.createParsed(_:equalsLoc:)")
 BridgedAssignExpr BridgedAssignExpr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cEqualsLoc);
+                                                 swift::SourceLoc equalsLoc);
 
 SWIFT_NAME("BridgedAwaitExpr.createParsed(_:awaitLoc:subExpr:)")
 BridgedAwaitExpr BridgedAwaitExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAwaitLoc,
+                                               swift::SourceLoc awaitLoc,
                                                BridgedExpr cSubExpr);
 
 SWIFT_NAME("BridgedBindOptionalExpr.createParsed(_:subExpr:questionLoc:)")
 BridgedBindOptionalExpr
 BridgedBindOptionalExpr_createParsed(BridgedASTContext cContext,
                                      BridgedExpr cSubExpr,
-                                     BridgedSourceLoc cQuestionLoc);
+                                     swift::SourceLoc questionLoc);
 
 SWIFT_NAME("BridgedBooleanLiteralExpr.createParsed(_:value:loc:)")
 BridgedBooleanLiteralExpr
 BridgedBooleanLiteralExpr_createParsed(BridgedASTContext cContext, bool value,
-                                       BridgedSourceLoc cTokenLoc);
+                                       swift::SourceLoc tokenLoc);
 
 SWIFT_NAME("BridgedBorrowExpr.createParsed(_:borrowLoc:subExpr:)")
 BridgedBorrowExpr BridgedBorrowExpr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cBorrowLoc,
+                                                 swift::SourceLoc borrowLoc,
                                                  BridgedExpr cSubExpr);
 
 SWIFT_NAME("BridgedCallExpr.createParsed(_:fn:args:)")
@@ -1875,23 +1759,21 @@ class BridgedCaptureListEntry {
 
 public:
   BRIDGED_INLINE BridgedCaptureListEntry(swift::CaptureListEntry CLE);
-
   BRIDGED_INLINE swift::CaptureListEntry unbridged() const;
+
+  BRIDGED_INLINE
+  SWIFT_COMPUTED_PROPERTY
+  BridgedVarDecl getVarDecl() const;
 };
 
 SWIFT_NAME("BridgedCaptureListEntry.createParsed(_:declContext:ownership:"
            "ownershipRange:name:nameLoc:equalLoc:initializer:)")
 BridgedCaptureListEntry BridegedCaptureListEntry_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedReferenceOwnership cOwnershipKind,
-    BridgedSourceRange cOwnershipRange, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedSourceLoc cEqualLoc,
+    BridgedReferenceOwnership cOwnershipKind, swift::SourceRange ownershipRange,
+    swift::Identifier name, swift::SourceLoc nameLoc, swift::SourceLoc equalLoc,
     BridgedExpr cInitializer);
 
-SWIFT_NAME("getter:BridgedCaptureListEntry.varDecl(self:)")
-BRIDGED_INLINE BridgedVarDecl
-BridegedCaptureListEntry_getVar(BridgedCaptureListEntry entry);
-
 SWIFT_NAME("BridgedCaptureListExpr.createParsed(_:captureList:closure:)")
 BridgedCaptureListExpr BridgedCaptureListExpr_createParsed(BridgedASTContext cContext,
                                                            BridgedArrayRef cCaptureList,
@@ -1902,12 +1784,12 @@ SWIFT_NAME("BridgedClosureExpr.createParsed(_:declContext:attributes:"
            "thrownType:arrowLoc:explicitResultType:inLoc:)")
 BridgedClosureExpr BridgedClosureExpr_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedDeclAttributes cAttributes, BridgedSourceRange cBracketRange,
+    BridgedDeclAttributes cAttributes, swift::SourceRange bracketRange,
     BridgedNullableVarDecl cCapturedSelfDecl,
-    BridgedNullableParameterList cParameterList, BridgedSourceLoc cAsyncLoc,
-    BridgedSourceLoc cThrowsLoc, BridgedNullableTypeRepr cThrownType,
-    BridgedSourceLoc cArrowLoc, BridgedNullableTypeRepr cExplicitResultType,
-    BridgedSourceLoc cInLoc);
+    BridgedNullableParameterList cParameterList, swift::SourceLoc asyncLoc,
+    swift::SourceLoc throwsLoc, BridgedNullableTypeRepr cThrownType,
+    swift::SourceLoc arrowLoc, BridgedNullableTypeRepr cExplicitResultType,
+    swift::SourceLoc inLoc);
 
 SWIFT_NAME("BridgedClosureExpr.getParameterList(self:)")
 BridgedParameterList
@@ -1929,25 +1811,25 @@ void BridgedClosureExpr_setBody(BridgedClosureExpr cClosure,
 
 SWIFT_NAME("BridgedCoerceExpr.createParsed(_:asLoc:type:)")
 BridgedCoerceExpr BridgedCoerceExpr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cAsLoc,
+                                                 swift::SourceLoc asLoc,
                                                  BridgedTypeRepr cType);
 
 SWIFT_NAME(
     "BridgedConditionalCheckedCastExpr.createParsed(_:asLoc:questionLoc:type:)")
 BridgedConditionalCheckedCastExpr
 BridgedConditionalCheckedCastExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAsLoc,
-                                               BridgedSourceLoc cQuestionLoc,
+                                               swift::SourceLoc asLoc,
+                                               swift::SourceLoc questionLoc,
                                                BridgedTypeRepr cType);
 
 SWIFT_NAME("BridgedConsumeExpr.createParsed(_:consumeLoc:subExpr:)")
 BridgedConsumeExpr BridgedConsumeExpr_createParsed(BridgedASTContext cContext,
-                                                   BridgedSourceLoc cConsumeLoc,
+                                                   swift::SourceLoc consumeLoc,
                                                    BridgedExpr cSubExpr);
 
 SWIFT_NAME("BridgedCopyExpr.createParsed(_:copyLoc:subExpr:)")
 BridgedCopyExpr BridgedCopyExpr_createParsed(BridgedASTContext cContext,
-                                             BridgedSourceLoc cCopyLoc,
+                                             swift::SourceLoc copyLoc,
                                              BridgedExpr cSubExpr);
 
 SWIFT_NAME("BridgedDeclRefExpr.create(_:decl:loc:isImplicit:)")
@@ -1959,127 +1841,127 @@ BridgedDeclRefExpr BridgedDeclRefExpr_create(BridgedASTContext cContext,
 SWIFT_NAME("BridgedDictionaryExpr.createParsed(_:lBracketLoc:elements:"
            "colonLocs:rBracketLoc:)")
 BridgedDictionaryExpr BridgedDictionaryExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLBracketLoc,
+    BridgedASTContext cContext, swift::SourceLoc lBracketLoc,
     BridgedArrayRef cElements, BridgedArrayRef cCommaLocs,
-    BridgedSourceLoc cRBracketLoc);
+    swift::SourceLoc rBracketLoc);
 
 SWIFT_NAME("BridgedDiscardAssignmentExpr.createParsed(_:loc:)")
 BridgedDiscardAssignmentExpr
 BridgedDiscardAssignmentExpr_createParsed(BridgedASTContext cContext,
-                                          BridgedSourceLoc cLoc);
+                                          swift::SourceLoc loc);
 
 SWIFT_NAME("BridgedDotSelfExpr.createParsed(_:subExpr:dotLoc:selfLoc:)")
 BridgedDotSelfExpr BridgedDotSelfExpr_createParsed(BridgedASTContext cContext,
                                                    BridgedExpr cSubExpr,
-                                                   BridgedSourceLoc cDotLoc,
-                                                   BridgedSourceLoc cSelfLoc);
+                                                   swift::SourceLoc dotLoc,
+                                                   swift::SourceLoc selfLoc);
 
 SWIFT_NAME("BridgedEditorPlaceholderExpr.createParsed(_:placeholder:loc:"
            "placeholderType:expansionType:)")
 BridgedEditorPlaceholderExpr BridgedEditorPlaceholderExpr_createParsed(
-    BridgedASTContext cContext, BridgedIdentifier cPlaceholderId,
-    BridgedSourceLoc cLoc, BridgedNullableTypeRepr cPlaceholderTyR,
+    BridgedASTContext cContext, swift::Identifier placeholderId,
+    swift::SourceLoc loc, BridgedNullableTypeRepr cPlaceholderTyR,
     BridgedNullableTypeRepr cExpansionTyR);
 
 SWIFT_NAME("BridgedErrorExpr.create(_:loc:)")
 BridgedErrorExpr BridgedErrorExpr_create(BridgedASTContext cContext,
-                                         BridgedSourceRange cRange);
+                                         swift::SourceRange range);
 
 SWIFT_NAME("BridgedFloatLiteralExpr.createParsed(_:value:loc:)")
 BridgedFloatLiteralExpr
 BridgedFloatLiteralExpr_createParsed(BridgedASTContext cContext,
                                      BridgedStringRef cStr,
-                                     BridgedSourceLoc cTokenLoc);
+                                     swift::SourceLoc tokenLoc);
 
 SWIFT_NAME("BridgedFloatLiteralExpr.setNegative(self:loc:)")
 BRIDGED_INLINE void
 BridgedFloatLiteralExpr_setNegative(BridgedFloatLiteralExpr cExpr,
-                                    BridgedSourceLoc cLoc);
+                                    swift::SourceLoc loc);
 
 SWIFT_NAME("BridgedForceTryExpr.createParsed(_:tryLoc:subExpr:exclaimLoc:)")
 BridgedForceTryExpr
 BridgedForceTryExpr_createParsed(BridgedASTContext cContext,
-                                 BridgedSourceLoc cTryLoc, BridgedExpr cSubExpr,
-                                 BridgedSourceLoc cExclaimLoc);
+                                 swift::SourceLoc tryLoc, BridgedExpr cSubExpr,
+                                 swift::SourceLoc exclaimLoc);
 
 SWIFT_NAME("BridgedForceValueExpr.createParsed(_:subExpr:exclaimLoc:)")
 BridgedForceValueExpr
 BridgedForceValueExpr_createParsed(BridgedASTContext cContext,
                                    BridgedExpr cSubExpr,
-                                   BridgedSourceLoc cExclaimLoc);
+                                   swift::SourceLoc exclaimLoc);
 
 SWIFT_NAME(
     "BridgedForcedCheckedCastExpr.createParsed(_:asLoc:exclaimLoc:type:)")
 BridgedForcedCheckedCastExpr BridgedForcedCheckedCastExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAsLoc,
-    BridgedSourceLoc cExclaimLoc, BridgedTypeRepr cType);
+    BridgedASTContext cContext, swift::SourceLoc asLoc,
+    swift::SourceLoc exclaimLoc, BridgedTypeRepr cType);
 
 SWIFT_NAME("BridgedUnresolvedSpecializeExpr.createParsed(_:subExpr:lAngleLoc:"
            "arguments:rAngleLoc:)")
 BridgedUnresolvedSpecializeExpr BridgedUnresolvedSpecializeExpr_createParsed(
     BridgedASTContext cContext, BridgedExpr cSubExpr,
-    BridgedSourceLoc cLAngleLoc, BridgedArrayRef cArguments,
-    BridgedSourceLoc cRAngleLoc);
+    swift::SourceLoc lAngleLoc, BridgedArrayRef cArguments,
+    swift::SourceLoc rAngleLoc);
 
 SWIFT_NAME("BridgedUnsafeExpr.createParsed(_:unsafeLoc:subExpr:)")
 BridgedUnsafeExpr BridgedUnsafeExpr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cUnsafeLoc,
+                                                 swift::SourceLoc unsafeLoc,
                                                  BridgedExpr cSubExpr);
 
 SWIFT_NAME("BridgedInOutExpr.createParsed(_:loc:subExpr:)")
 BridgedInOutExpr BridgedInOutExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cLoc,
+                                               swift::SourceLoc loc,
                                                BridgedExpr cSubExpr);
 
 SWIFT_NAME("BridgedIntegerLiteralExpr.createParsed(_:value:loc:)")
 BridgedIntegerLiteralExpr
 BridgedIntegerLiteralExpr_createParsed(BridgedASTContext cContext,
                                        BridgedStringRef cStr,
-                                       BridgedSourceLoc cTokenLoc);
+                                       swift::SourceLoc tokenLoc);
 
 SWIFT_NAME("BridgedIntegerLiteralExpr.setNegative(self:loc:)")
 BRIDGED_INLINE void
 BridgedIntegerLiteralExpr_setNegative(BridgedIntegerLiteralExpr cExpr,
-                                      BridgedSourceLoc cLoc);
+                                      swift::SourceLoc loc);
 
 SWIFT_NAME("BridgedInterpolatedStringLiteralExpr.createParsed(_:loc:"
            "literalCapacity:interpolationCount:appendingExpr:)")
 BridgedInterpolatedStringLiteralExpr
 BridgedInterpolatedStringLiteralExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLoc, size_t literalCapacity,
+    BridgedASTContext cContext, swift::SourceLoc loc, size_t literalCapacity,
     size_t interpolationCount, BridgedTapExpr cAppendingExpr);
 
 SWIFT_NAME("BridgedIsExpr.createParsed(_:isLoc:type:)")
 BridgedIsExpr BridgedIsExpr_createParsed(BridgedASTContext cContext,
-                                         BridgedSourceLoc cIsLoc,
+                                         swift::SourceLoc isLoc,
                                          BridgedTypeRepr cType);
 
 SWIFT_NAME("BridgedKeyPathDotExpr.createParsed(_:loc:)")
 BridgedKeyPathDotExpr
 BridgedKeyPathDotExpr_createParsed(BridgedASTContext cContext,
-                                   BridgedSourceLoc cLoc);
+                                   swift::SourceLoc loc);
 
 SWIFT_NAME("BridgedKeyPathExpr.createParsed(_:backslashLoc:parsedRoot:"
            "parsedPath:hasLeadingDot:)")
 BridgedKeyPathExpr BridgedKeyPathExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cBackslashLoc,
+    BridgedASTContext cContext, swift::SourceLoc backslashLoc,
     BridgedNullableExpr cParsedRoot, BridgedNullableExpr cParsedPath,
     bool hasLeadingDot);
 
 SWIFT_NAME("BridgedKeyPathExpr.createParsedPoundKeyPath(_:poundLoc:lParenLoc:"
            "names:nameLocs:rParenLoc:)")
 BridgedKeyPathExpr BridgedKeyPathExpr_createParsedPoundKeyPath(
-    BridgedASTContext cContext, BridgedSourceLoc cPoundLoc,
-    BridgedSourceLoc cLParenLoc, BridgedArrayRef cNames,
-    BridgedArrayRef cNameLocs, BridgedSourceLoc cRParenLoc);
+    BridgedASTContext cContext, swift::SourceLoc poundLoc,
+    swift::SourceLoc lParenLoc, BridgedArrayRef cNames,
+    BridgedArrayRef cNameLocs, swift::SourceLoc rParenLoc);
 
 SWIFT_NAME("BridgedMacroExpansionExpr.createParsed(_:poundLoc:macroNameRef:"
            "macroNameLoc:leftAngleLoc:genericArgs:rightAngleLoc:args:)")
 BridgedMacroExpansionExpr BridgedMacroExpansionExpr_createParsed(
-    BridgedDeclContext cDeclContext, BridgedSourceLoc cPoundLoc,
+    BridgedDeclContext cDeclContext, swift::SourceLoc poundLoc,
     BridgedDeclNameRef cMacroNameRef, BridgedDeclNameLoc cMacroNameLoc,
-    BridgedSourceLoc cLeftAngleLoc, BridgedArrayRef cGenericArgs,
-    BridgedSourceLoc cRightAngleLoc, BridgedNullableArgumentList cArgList);
+    swift::SourceLoc leftAngleLoc, BridgedArrayRef cGenericArgs,
+    swift::SourceLoc rightAngleLoc, BridgedNullableArgumentList cArgList);
 
 enum ENUM_EXTENSIBILITY_ATTR(open) BridgedMagicIdentifierLiteralKind : uint8_t {
 #define MAGIC_IDENTIFIER(NAME, STRING)                                         \
@@ -2096,12 +1978,12 @@ SWIFT_NAME("BridgedMagicIdentifierLiteralExpr.createParsed(_:kind:loc:)")
 BridgedMagicIdentifierLiteralExpr
 BridgedMagicIdentifierLiteralExpr_createParsed(
     BridgedASTContext cContext, BridgedMagicIdentifierLiteralKind cKind,
-    BridgedSourceLoc cLoc);
+    swift::SourceLoc loc);
 
 SWIFT_NAME("BridgedNilLiteralExpr.createParsed(_:nilKeywordLoc:)")
 BridgedNilLiteralExpr
 BridgedNilLiteralExpr_createParsed(BridgedASTContext cContext,
-                                   BridgedSourceLoc cNilKeywordLoc);
+                                   swift::SourceLoc nilKeywordLoc);
 
 enum ENUM_EXTENSIBILITY_ATTR(open) BridgedObjCSelectorKind {
   BridgedObjCSelectorKindMethod,
@@ -2113,9 +1995,9 @@ SWIFT_NAME("BridgedObjCSelectorExpr.createParsed(_:kind:keywordLoc:lParenLoc:"
            "modifierLoc:subExpr:rParenLoc:)")
 BridgedObjCSelectorExpr BridgedObjCSelectorExpr_createParsed(
     BridgedASTContext cContext, BridgedObjCSelectorKind cKind,
-    BridgedSourceLoc cKeywordLoc, BridgedSourceLoc cLParenLoc,
-    BridgedSourceLoc cModifierLoc, BridgedExpr cSubExpr,
-    BridgedSourceLoc cRParenLoc);
+    swift::SourceLoc keywordLoc, swift::SourceLoc lParenLoc,
+    swift::SourceLoc modifierLoc, BridgedExpr cSubExpr,
+    swift::SourceLoc rParenLoc);
 
 enum ENUM_EXTENSIBILITY_ATTR(open) BridgedObjectLiteralKind : size_t {
 #define POUND_OBJECT_LITERAL(Name, Desc, Proto) BridgedObjectLiteralKind_##Name,
@@ -2129,31 +2011,31 @@ BridgedObjectLiteralKind_fromString(BridgedStringRef cStr);
 
 SWIFT_NAME("BridgedObjectLiteralExpr.createParsed(_:poundLoc:kind:args:)")
 BridgedObjectLiteralExpr BridgedObjectLiteralExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cPoundLoc,
+    BridgedASTContext cContext, swift::SourceLoc poundLoc,
     BridgedObjectLiteralKind cKind, BridgedArgumentList args);
 
 SWIFT_NAME("BridgedOptionalTryExpr.createParsed(_:tryLoc:subExpr:questionLoc:)")
 BridgedOptionalTryExpr BridgedOptionalTryExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cTryLoc, BridgedExpr cSubExpr,
-    BridgedSourceLoc cQuestionLoc);
+    BridgedASTContext cContext, swift::SourceLoc tryLoc, BridgedExpr cSubExpr,
+    swift::SourceLoc questionLoc);
 
 SWIFT_NAME("BridgedPackElementExpr.createParsed(_:eachLoc:packRefExpr:)")
 BridgedPackElementExpr
 BridgedPackElementExpr_createParsed(BridgedASTContext cContext,
-                                    BridgedSourceLoc cEachLoc,
+                                    swift::SourceLoc eachLoc,
                                     BridgedExpr cPackRefExpr);
 
 SWIFT_NAME("BridgedPackExpansionExpr.createParsed(_:repeatLoc:patternExpr:)")
 BridgedPackExpansionExpr
 BridgedPackExpansionExpr_createParsed(BridgedASTContext cContext,
-                                      BridgedSourceLoc cRepeatLoc,
+                                      swift::SourceLoc repeatLoc,
                                       BridgedExpr cPatternExpr);
 
 SWIFT_NAME("BridgedParenExpr.createParsed(_:leftParenLoc:expr:rightParenLoc:)")
 BridgedParenExpr BridgedParenExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cLParen,
+                                               swift::SourceLoc lParen,
                                                BridgedExpr cExpr,
-                                               BridgedSourceLoc cRParen);
+                                               swift::SourceLoc rParen);
 
 SWIFT_NAME("BridgedPostfixUnaryExpr.createParsed(_:operator:operand:)")
 BridgedPostfixUnaryExpr
@@ -2183,13 +2065,13 @@ class BridgedRegexLiteralPatternFeatureKind final {
 };
 
 class BridgedRegexLiteralPatternFeature final {
-  BridgedCharSourceRange Range;
+  swift::CharSourceRange Range;
   BridgedRegexLiteralPatternFeatureKind Kind;
 
 public:
   SWIFT_NAME("init(kind:at:)")
   BridgedRegexLiteralPatternFeature(BridgedRegexLiteralPatternFeatureKind kind,
-                                    BridgedCharSourceRange range)
+                                    swift::CharSourceRange range)
       : Range(range), Kind(kind) {}
 
   using UnbridgedTy = swift::RegexLiteralPatternFeature;
@@ -2230,7 +2112,7 @@ class BridgedRegexLiteralPatternFeatures final {
 SWIFT_NAME("BridgedRegexLiteralExpr.createParsed(_:loc:regexText:)")
 BridgedRegexLiteralExpr
 BridgedRegexLiteralExpr_createParsed(BridgedASTContext cContext,
-                                     BridgedSourceLoc cLoc,
+                                     swift::SourceLoc loc,
                                      BridgedStringRef cRegexText);
 
 SWIFT_NAME("BridgedSequenceExpr.createParsed(_:exprs:)")
@@ -2247,12 +2129,11 @@ SWIFT_NAME("BridgedStringLiteralExpr.createParsed(_:value:loc:)")
 BridgedStringLiteralExpr
 BridgedStringLiteralExpr_createParsed(BridgedASTContext cContext,
                                       BridgedStringRef cStr,
-                                      BridgedSourceLoc cTokenLoc);
+                                      swift::SourceLoc tokenLoc);
 
 SWIFT_NAME("BridgedSuperRefExpr.createParsed(_:superLoc:)")
-BridgedSuperRefExpr
-BridgedSuperRefExpr_createParsed(BridgedASTContext cContext,
-                                 BridgedSourceLoc cSuperLoc);
+BridgedSuperRefExpr BridgedSuperRefExpr_createParsed(BridgedASTContext cContext,
+                                                     swift::SourceLoc superLoc);
 
 SWIFT_NAME("BridgedSubscriptExpr.createParsed(_:baseExpr:args:)")
 BridgedSubscriptExpr
@@ -2265,20 +2146,21 @@ BridgedTapExpr BridgedTapExpr_create(BridgedASTContext cContext,
                                      BridgedBraceStmt cBody);
 
 SWIFT_NAME("BridgedTernaryExpr.createParsed(_:questionLoc:thenExpr:colonLoc:)")
-BridgedTernaryExpr BridgedTernaryExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cQuestionLoc,
-    BridgedExpr cThenExpr, BridgedSourceLoc cColonLoc);
+BridgedTernaryExpr BridgedTernaryExpr_createParsed(BridgedASTContext cContext,
+                                                   swift::SourceLoc questionLoc,
+                                                   BridgedExpr cThenExpr,
+                                                   swift::SourceLoc colonLoc);
 
 SWIFT_NAME("BridgedTryExpr.createParsed(_:tryLoc:subExpr:)")
 BridgedTryExpr BridgedTryExpr_createParsed(BridgedASTContext cContext,
-                                           BridgedSourceLoc cTryLoc,
+                                           swift::SourceLoc tryLoc,
                                            BridgedExpr cSubExpr);
 
 SWIFT_NAME("BridgedTupleExpr.createParsed(_:leftParenLoc:exprs:labels:"
            "labelLocs:rightParenLoc:)")
 BridgedTupleExpr BridgedTupleExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLParen, BridgedArrayRef subs,
-    BridgedArrayRef names, BridgedArrayRef cNameLocs, BridgedSourceLoc cRParen);
+    BridgedASTContext cContext, swift::SourceLoc lParen, BridgedArrayRef subs,
+    BridgedArrayRef names, BridgedArrayRef cNameLocs, swift::SourceLoc rParen);
 
 SWIFT_NAME("BridgedTupleExpr.createParsedDictionaryElement(_:key:value:)")
 BridgedTupleExpr BridgedTupleExpr_createParsedDictionaryElement(
@@ -2302,12 +2184,12 @@ BridgedUnresolvedDeclRefExpr BridgedUnresolvedDeclRefExpr_createParsed(
 
 SWIFT_NAME("BridgedUnresolvedDotExpr.createParsed(_:base:dotLoc:name:nameLoc:)")
 BridgedUnresolvedDotExpr BridgedUnresolvedDotExpr_createParsed(
-    BridgedASTContext cContext, BridgedExpr base, BridgedSourceLoc cDotLoc,
+    BridgedASTContext cContext, BridgedExpr base, swift::SourceLoc dotLoc,
     BridgedDeclNameRef cName, BridgedDeclNameLoc cNameLoc);
 
 SWIFT_NAME("BridgedUnresolvedMemberExpr.createParsed(_:dotLoc:name:nameLoc:)")
 BridgedUnresolvedMemberExpr BridgedUnresolvedMemberExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cDotLoc,
+    BridgedASTContext cContext, swift::SourceLoc dotLoc,
     BridgedDeclNameRef cName, BridgedDeclNameLoc cNameLoc);
 
 SWIFT_NAME("BridgedUnresolvedPatternExpr.createParsed(_:pattern:)")
@@ -2327,9 +2209,9 @@ void BridgedExpr_dump(BridgedExpr expr);
 
 struct BridgedLabeledStmtInfo {
   SWIFT_NAME("name")
-  BridgedIdentifier Name;
+  swift::Identifier Name;
   SWIFT_NAME("loc")
-  BridgedSourceLoc Loc;
+  swift::SourceLoc Loc;
 
   BRIDGED_INLINE swift::LabeledStmtInfo unbridged() const;
 };
@@ -2350,7 +2232,7 @@ BridgedStmtConditionElement_createBoolean(BridgedExpr expr);
 SWIFT_NAME("BridgedStmtConditionElement.createPatternBinding(_:introducerLoc:"
            "pattern:initializer:)")
 BridgedStmtConditionElement BridgedStmtConditionElement_createPatternBinding(
-    BridgedASTContext cContext, BridgedSourceLoc cIntroducerLoc,
+    BridgedASTContext cContext, swift::SourceLoc introducerLoc,
     BridgedPattern cPattern, BridgedExpr cInitializer);
 
 SWIFT_NAME("BridgedStmtConditionElement.createPoundAvailable(info:)")
@@ -2360,16 +2242,16 @@ BridgedStmtConditionElement BridgedStmtConditionElement_createPoundAvailable(
 SWIFT_NAME("BridgedPoundAvailableInfo.createParsed(_:poundLoc:lParenLoc:specs:"
            "rParenLoc:isUnavailable:)")
 BridgedPoundAvailableInfo BridgedPoundAvailableInfo_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cPoundLoc,
-    BridgedSourceLoc cLParenLoc, BridgedArrayRef cSpecs,
-    BridgedSourceLoc cRParenLoc, bool isUnavailability);
+    BridgedASTContext cContext, swift::SourceLoc poundLoc,
+    swift::SourceLoc lParenLoc, BridgedArrayRef cSpecs,
+    swift::SourceLoc rParenLoc, bool isUnavailability);
 
 SWIFT_NAME("BridgedStmtConditionElement.createHasSymbol(_:poundLoc:lParenLoc:"
            "symbol:rParenLoc:)")
 BridgedStmtConditionElement BridgedStmtConditionElement_createHasSymbol(
-    BridgedASTContext cContext, BridgedSourceLoc cPoundLoc,
-    BridgedSourceLoc cLParenLoc, BridgedNullableExpr cSymbolExpr,
-    BridgedSourceLoc cRParenLoc);
+    BridgedASTContext cContext, swift::SourceLoc poundLoc,
+    swift::SourceLoc lParenLoc, BridgedNullableExpr cSymbolExpr,
+    swift::SourceLoc rParenLoc);
 
 struct BridgedCaseLabelItemInfo {
   SWIFT_NAME("isDefault")
@@ -2377,63 +2259,63 @@ struct BridgedCaseLabelItemInfo {
   SWIFT_NAME("pattern")
   BridgedPattern ThePattern;
   SWIFT_NAME("whereLoc")
-  BridgedSourceLoc WhereLoc;
+  swift::SourceLoc WhereLoc;
   SWIFT_NAME("guardExpr")
   BridgedNullableExpr GuardExpr;
 };
 
 SWIFT_NAME("BridgedBraceStmt.createParsed(_:lBraceLoc:elements:rBraceLoc:)")
 BridgedBraceStmt BridgedBraceStmt_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cLBLoc,
+                                               swift::SourceLoc lBLoc,
                                                BridgedArrayRef elements,
-                                               BridgedSourceLoc cRBLoc);
+                                               swift::SourceLoc rBLoc);
 
 SWIFT_NAME("BridgedBraceStmt.createImplicit(_:lBraceLoc:element:rBraceLoc:)")
 BridgedBraceStmt BridgedBraceStmt_createImplicit(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cLBLoc,
+                                                 swift::SourceLoc lBLoc,
                                                  BridgedASTNode element,
-                                                 BridgedSourceLoc cRBLoc);
+                                                 swift::SourceLoc rBLoc);
 
 SWIFT_NAME("BridgedBreakStmt.createParsed(_:loc:targetName:targetLoc:)")
 BridgedBreakStmt BridgedBreakStmt_createParsed(BridgedDeclContext cDeclContext,
-                                               BridgedSourceLoc cLoc,
-                                               BridgedIdentifier cTargetName,
-                                               BridgedSourceLoc cTargetLoc);
+                                               swift::SourceLoc loc,
+                                               swift::Identifier targetName,
+                                               swift::SourceLoc targetLoc);
 
 SWIFT_NAME("BridgedCaseStmt.createParsedSwitchCase(_:introducerLoc:"
            "caseLabelItems:unknownAttrLoc:terminatorLoc:body:)")
 BridgedCaseStmt BridgedCaseStmt_createParsedSwitchCase(
-    BridgedASTContext cContext, BridgedSourceLoc cIntroducerLoc,
-    BridgedArrayRef cCaseLabelItems, BridgedSourceLoc cUnknownAttrLoc,
-    BridgedSourceLoc cTerminatorLoc, BridgedBraceStmt cBody);
+    BridgedASTContext cContext, swift::SourceLoc introducerLoc,
+    BridgedArrayRef cCaseLabelItems, swift::SourceLoc unknownAttrLoc,
+    swift::SourceLoc terminatorLoc, BridgedBraceStmt cBody);
 
 SWIFT_NAME(
     "BridgedCaseStmt.createParsedDoCatch(_:catchLoc:caseLabelItems:body:)")
 BridgedCaseStmt BridgedCaseStmt_createParsedDoCatch(
-    BridgedASTContext cContext, BridgedSourceLoc cCatchLoc,
+    BridgedASTContext cContext, swift::SourceLoc catchLoc,
     BridgedArrayRef cCaseLabelItems, BridgedBraceStmt cBody);
 
 SWIFT_NAME("BridgedContinueStmt.createParsed(_:loc:targetName:targetLoc:)")
 BridgedContinueStmt BridgedContinueStmt_createParsed(
-    BridgedDeclContext cDeclContext, BridgedSourceLoc cLoc,
-    BridgedIdentifier cTargetName, BridgedSourceLoc cTargetLoc);
+    BridgedDeclContext cDeclContext, swift::SourceLoc loc,
+    swift::Identifier targetName, swift::SourceLoc targetLoc);
 
 SWIFT_NAME("BridgedDeferStmt.createParsed(_:deferLoc:)")
 BridgedDeferStmt BridgedDeferStmt_createParsed(BridgedDeclContext cDeclContext,
-                                               BridgedSourceLoc cDeferLoc);
+                                               swift::SourceLoc deferLoc);
 
 SWIFT_NAME("getter:BridgedDeferStmt.tempDecl(self:)")
 BridgedFuncDecl BridgedDeferStmt_getTempDecl(BridgedDeferStmt bridged);
 
 SWIFT_NAME("BridgedDiscardStmt.createParsed(_:discardLoc:subExpr:)")
 BridgedDiscardStmt BridgedDiscardStmt_createParsed(BridgedASTContext cContext,
-                                                   BridgedSourceLoc cDiscardLoc,
+                                                   swift::SourceLoc discardLoc,
                                                    BridgedExpr cSubExpr);
 
 SWIFT_NAME("BridgedDoStmt.createParsed(_:labelInfo:doLoc:body:)")
 BridgedDoStmt BridgedDoStmt_createParsed(BridgedASTContext cContext,
                                          BridgedLabeledStmtInfo cLabelInfo,
-                                         BridgedSourceLoc cDoLoc,
+                                         swift::SourceLoc doLoc,
                                          BridgedBraceStmt cBody);
 
 SWIFT_NAME(
@@ -2441,28 +2323,27 @@ SWIFT_NAME(
     "body:catches:)")
 BridgedDoCatchStmt BridgedDoCatchStmt_createParsed(
     BridgedDeclContext cDeclContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cDoLoc, BridgedSourceLoc cThrowsLoc,
+    swift::SourceLoc doLoc, swift::SourceLoc throwsLoc,
     BridgedNullableTypeRepr cThrownType, BridgedStmt cBody,
     BridgedArrayRef cCatches);
 
 SWIFT_NAME("BridgedFallthroughStmt.createParsed(loc:declContext:)")
 BridgedFallthroughStmt
-BridgedFallthroughStmt_createParsed(BridgedSourceLoc cLoc,
+BridgedFallthroughStmt_createParsed(swift::SourceLoc loc,
                                     BridgedDeclContext cDC);
 
 SWIFT_NAME("BridgedForEachStmt.createParsed(_:labelInfo:forLoc:tryLoc:awaitLoc:"
            "unsafeLoc:pattern:inLoc:sequence:whereLoc:whereExpr:body:)")
 BridgedForEachStmt BridgedForEachStmt_createParsed(
     BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cForLoc, BridgedSourceLoc cTryLoc,
-    BridgedSourceLoc cAwaitLoc, BridgedSourceLoc cUnsafeLoc,
-    BridgedPattern cPat, BridgedSourceLoc cInLoc,
-    BridgedExpr cSequence, BridgedSourceLoc cWhereLoc,
+    swift::SourceLoc forLoc, swift::SourceLoc tryLoc, swift::SourceLoc awaitLoc,
+    swift::SourceLoc unsafeLoc, BridgedPattern cPat, swift::SourceLoc inLoc,
+    BridgedExpr cSequence, swift::SourceLoc whereLoc,
     BridgedNullableExpr cWhereExpr, BridgedBraceStmt cBody);
 
 SWIFT_NAME("BridgedGuardStmt.createParsed(_:guardLoc:conds:body:)")
 BridgedGuardStmt BridgedGuardStmt_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cGuardLoc,
+                                               swift::SourceLoc guardLoc,
                                                BridgedArrayRef cConds,
                                                BridgedBraceStmt cBody);
 
@@ -2470,56 +2351,56 @@ SWIFT_NAME("BridgedIfStmt.createParsed(_:labelInfo:ifLoc:conditions:then:"
            "elseLoc:else:)")
 BridgedIfStmt BridgedIfStmt_createParsed(
     BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cIfLoc, BridgedArrayRef cConds, BridgedBraceStmt cThen,
-    BridgedSourceLoc cElseLoc, BridgedNullableStmt cElse);
+    swift::SourceLoc ifLoc, BridgedArrayRef cConds, BridgedBraceStmt cThen,
+    swift::SourceLoc elseLoc, BridgedNullableStmt cElse);
 
 SWIFT_NAME("BridgedPoundAssertStmt.createParsed(_:range:condition:message:)")
 BridgedPoundAssertStmt BridgedPoundAssertStmt_createParsed(
-    BridgedASTContext cContext, BridgedSourceRange cRange,
+    BridgedASTContext cContext, swift::SourceRange range,
     BridgedExpr cConditionExpr, BridgedStringRef cMessage);
 
 SWIFT_NAME("BridgedRepeatWhileStmt.createParsed(_:labelInfo:repeatLoc:cond:"
            "whileLoc:body:)")
 BridgedRepeatWhileStmt BridgedRepeatWhileStmt_createParsed(
     BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cRepeatLoc, BridgedExpr cCond, BridgedSourceLoc cWhileLoc,
+    swift::SourceLoc repeatLoc, BridgedExpr cCond, swift::SourceLoc whileLoc,
     BridgedStmt cBody);
 
 SWIFT_NAME("BridgedReturnStmt.createParsed(_:loc:expr:)")
 BridgedReturnStmt BridgedReturnStmt_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cLoc,
+                                                 swift::SourceLoc loc,
                                                  BridgedNullableExpr expr);
 
 SWIFT_NAME("BridgedSwitchStmt.createParsed(_:labelInfo:switchLoc:subjectExpr:"
            "lBraceLoc:cases:rBraceLoc:)")
 BridgedSwitchStmt BridgedSwitchStmt_createParsed(
     BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cSwitchLoc, BridgedExpr cSubjectExpr,
-    BridgedSourceLoc cLBraceLoc, BridgedArrayRef cCases,
-    BridgedSourceLoc cRBraceLoc);
+    swift::SourceLoc switchLoc, BridgedExpr cSubjectExpr,
+    swift::SourceLoc lBraceLoc, BridgedArrayRef cCases,
+    swift::SourceLoc rBraceLoc);
 
 SWIFT_NAME("BridgedThenStmt.createParsed(_:thenLoc:result:)")
 BridgedThenStmt BridgedThenStmt_createParsed(BridgedASTContext cContext,
-                                             BridgedSourceLoc cThenLoc,
+                                             swift::SourceLoc thenLoc,
                                              BridgedExpr cResult);
 
 SWIFT_NAME("BridgedThrowStmt.createParsed(_:throwLoc:subExpr:)")
 BridgedThrowStmt BridgedThrowStmt_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cThrowLoc,
+                                               swift::SourceLoc throwLoc,
                                                BridgedExpr cSubExpr);
 
 SWIFT_NAME("BridgedWhileStmt.createParsed(_:labelInfo:whileLoc:cond:body:)")
 BridgedWhileStmt BridgedWhileStmt_createParsed(
     BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cWhileLoc, BridgedArrayRef cCond, BridgedStmt cBody);
+    swift::SourceLoc whileLoc, BridgedArrayRef cCond, BridgedStmt cBody);
 
 SWIFT_NAME(
     "BridgedYieldStmt.createParsed(_:yieldLoc:lParenLoc:yields:rParenLoc:)")
 BridgedYieldStmt BridgedYieldStmt_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cYieldLoc,
-                                               BridgedSourceLoc cLParenLoc,
+                                               swift::SourceLoc yieldLoc,
+                                               swift::SourceLoc lParenLoc,
                                                BridgedArrayRef cYields,
-                                               BridgedSourceLoc cRParenLoc);
+                                               swift::SourceLoc rParenLoc);
 
 SWIFT_NAME("BridgedStmt.dump(self:)")
 void BridgedStmt_dump(BridgedStmt statement);
@@ -2562,20 +2443,16 @@ class BridgedTypeOrCustomAttr {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCustomAttr castToCustomAttr() const;
 };
 
-// Bridged type attribute kinds, which mirror TypeAttrKind exactly.
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedTypeAttrKind {
-#define TYPE_ATTR(_, CLASS) BridgedTypeAttrKind##CLASS,
-#include "swift/AST/TypeAttr.def"
-  BridgedTypeAttrKindNone,
-};
+BRIDGED_OPTIONAL(swift::TypeAttrKind, TypeAttrKind)
 
-SWIFT_NAME("BridgedTypeAttrKind.init(from:)")
-BridgedTypeAttrKind BridgedTypeAttrKind_fromString(BridgedStringRef cStr);
+SWIFT_NAME("BridgedOptionalTypeAttrKind.init(from:)")
+BridgedOptionalTypeAttrKind
+BridgedOptionalTypeAttrKind_fromString(BridgedStringRef cStr);
 
 SWIFT_NAME("BridgedTypeAttribute.createSimple(_:kind:atLoc:nameLoc:)")
 BridgedTypeAttribute BridgedTypeAttribute_createSimple(
-    BridgedASTContext cContext, BridgedTypeAttrKind cKind,
-    BridgedSourceLoc cAtLoc, BridgedSourceLoc cNameLoc);
+    BridgedASTContext cContext, swift::TypeAttrKind kind,
+    swift::SourceLoc atLoc, swift::SourceLoc nameLoc);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedIsolatedTypeAttrIsolationKind {
   BridgedIsolatedTypeAttrIsolationKind_DynamicIsolation,
@@ -2584,49 +2461,35 @@ enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedIsolatedTypeAttrIsolationKind {
 SWIFT_NAME("BridgedConventionTypeAttr.createParsed(_:atLoc:nameLoc:parensRange:"
            "name:nameLoc:witnessMethodProtocol:clangType:clangTypeLoc:)")
 BridgedConventionTypeAttr BridgedConventionTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cKwLoc, BridgedSourceRange cParens, BridgedStringRef cName,
-    BridgedSourceLoc cNameLoc, BridgedDeclNameRef cWitnessMethodProtocol,
-    BridgedStringRef cClangType, BridgedSourceLoc cClangTypeLoc);
-
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedExecutionTypeAttrExecutionKind {
-  BridgedExecutionTypeAttrExecutionKind_Concurrent,
-  BridgedExecutionTypeAttrExecutionKind_Caller
-};
+    BridgedASTContext cContext, swift::SourceLoc atLoc, swift::SourceLoc kwLoc,
+    swift::SourceRange parens, BridgedStringRef cName, swift::SourceLoc nameLoc,
+    BridgedDeclNameRef cWitnessMethodProtocol, BridgedStringRef cClangType,
+    swift::SourceLoc clangTypeLoc);
 
 SWIFT_NAME("BridgedDifferentiableTypeAttr.createParsed(_:atLoc:nameLoc:"
            "parensRange:kind:kindLoc:)")
 BridgedDifferentiableTypeAttr BridgedDifferentiableTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cNameLoc, BridgedSourceRange cParensRange,
-    BridgedDifferentiabilityKind cKind, BridgedSourceLoc cKindLoc);
-
-SWIFT_NAME("BridgedExecutionTypeAttr.createParsed(_:atLoc:nameLoc:parensRange:"
-           "behavior:behaviorLoc:)")
-BridgedExecutionTypeAttr BridgedExecutionTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cNameLoc, BridgedSourceRange cParensRange,
-    BridgedExecutionTypeAttrExecutionKind behavior,
-    BridgedSourceLoc cBehaviorLoc);
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceLoc nameLoc, swift::SourceRange parensRange,
+    BridgedDifferentiabilityKind cKind, swift::SourceLoc kindLoc);
 
 SWIFT_NAME("BridgedIsolatedTypeAttr.createParsed(_:atLoc:nameLoc:parensRange:"
            "isolationKind:isolationKindLoc:)")
 BridgedIsolatedTypeAttr BridgedIsolatedTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cNameLoc, BridgedSourceRange cParensRange,
+    BridgedASTContext cContext, swift::SourceLoc atLoc,
+    swift::SourceLoc nameLoc, swift::SourceRange parensRange,
 
     BridgedIsolatedTypeAttrIsolationKind cIsolation,
-    BridgedSourceLoc cIsolationLoc);
+    swift::SourceLoc isolationLoc);
 
 SWIFT_NAME("BridgedOpaqueReturnTypeOfTypeAttr.createParsed(_:atLoc:nameLoc:"
            "parensRange:"
            "mangled:mangledLoc:index:indexLoc:)")
 BridgedOpaqueReturnTypeOfTypeAttr
 BridgedOpaqueReturnTypeOfTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cKwLoc, BridgedSourceRange cParens,
-    BridgedStringRef cMangled, BridgedSourceLoc cMangledDoc, size_t index,
-    BridgedSourceLoc cIndexLoc);
+    BridgedASTContext cContext, swift::SourceLoc atLoc, swift::SourceLoc kwLoc,
+    swift::SourceRange parens, BridgedStringRef cMangled,
+    swift::SourceLoc mangledDoc, size_t index, swift::SourceLoc indexLoc);
 
 //===----------------------------------------------------------------------===//
 // MARK: TypeReprs
@@ -2634,13 +2497,13 @@ BridgedOpaqueReturnTypeOfTypeAttr_createParsed(
 
 SWIFT_NAME("BridgedUnqualifiedIdentTypeRepr.createParsed(_:loc:name:)")
 BridgedUnqualifiedIdentTypeRepr BridgedUnqualifiedIdentTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLoc, BridgedIdentifier id);
+    BridgedASTContext cContext, swift::SourceLoc loc, swift::Identifier id);
 
 SWIFT_NAME(
     "BridgedArrayTypeRepr.createParsed(_:base:leftSquareLoc:rightSquareLoc:)")
 BridgedArrayTypeRepr BridgedArrayTypeRepr_createParsed(
     BridgedASTContext cContext, BridgedTypeRepr base,
-    BridgedSourceLoc cLSquareLoc, BridgedSourceLoc cRSquareLoc);
+    swift::SourceLoc lSquareLoc, swift::SourceLoc rSquareLoc);
 
 SWIFT_NAME("BridgedAttributedTypeRepr.createParsed(_:base:attributes:)")
 BridgedAttributedTypeRepr
@@ -2651,82 +2514,82 @@ BridgedAttributedTypeRepr_createParsed(BridgedASTContext cContext,
 SWIFT_NAME("BridgedCompositionTypeRepr.createEmpty(_:anyKeywordLoc:)")
 BridgedCompositionTypeRepr
 BridgedCompositionTypeRepr_createEmpty(BridgedASTContext cContext,
-                                       BridgedSourceLoc cAnyLoc);
+                                       swift::SourceLoc anyLoc);
 
 SWIFT_NAME("BridgedCompositionTypeRepr.createParsed(_:types:ampersandLoc:)")
 BridgedCompositionTypeRepr
 BridgedCompositionTypeRepr_createParsed(BridgedASTContext cContext,
                                         BridgedArrayRef types,
-                                        BridgedSourceLoc cFirstAmpLoc);
+                                        swift::SourceLoc firstAmpLoc);
 
 SWIFT_NAME("BridgedCompileTimeLiteralTypeRepr.createParsed(_:base:specifierLoc:)")
 BridgedCompileTimeLiteralTypeRepr
 BridgedCompileTimeLiteralTypeRepr_createParsed(BridgedASTContext cContext,
                                                BridgedTypeRepr base,
-                                               BridgedSourceLoc cSpecifierLoc);
+                                               swift::SourceLoc specifierLoc);
 
 SWIFT_NAME("BridgedDeclRefTypeRepr.createParsed(_:base:name:nameLoc:"
            "genericArguments:angleRange:)")
 BridgedDeclRefTypeRepr BridgedDeclRefTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedTypeRepr cBase, BridgedIdentifier cName,
-    BridgedSourceLoc cLoc, BridgedArrayRef cGenericArguments,
-    BridgedSourceRange cAngleRange);
+    BridgedASTContext cContext, BridgedTypeRepr cBase, swift::Identifier name,
+    swift::SourceLoc loc, BridgedArrayRef cGenericArguments,
+    swift::SourceRange angleRange);
 
 SWIFT_NAME("BridgedDictionaryTypeRepr.createParsed(_:leftSquareLoc:keyType:"
            "colonLoc:valueType:rightSquareLoc:)")
 BridgedDictionaryTypeRepr BridgedDictionaryTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLSquareLoc,
-    BridgedTypeRepr keyType, BridgedSourceLoc cColonloc,
-    BridgedTypeRepr valueType, BridgedSourceLoc cRSquareLoc);
+    BridgedASTContext cContext, swift::SourceLoc lSquareLoc,
+    BridgedTypeRepr keyType, swift::SourceLoc colonloc,
+    BridgedTypeRepr valueType, swift::SourceLoc rSquareLoc);
 
 SWIFT_NAME("BridgedErrorTypeRepr.create(_:range:)")
 BridgedErrorTypeRepr BridgedErrorTypeRepr_create(BridgedASTContext cContext,
-                                                 BridgedSourceRange cRange);
+                                                 swift::SourceRange range);
 
 SWIFT_NAME("BridgedFunctionTypeRepr.createParsed(_:argsType:asyncLoc:throwsLoc:"
            "thrownType:arrowLoc:resultType:)")
 BridgedFunctionTypeRepr BridgedFunctionTypeRepr_createParsed(
     BridgedASTContext cContext, BridgedTypeRepr argsTy,
-    BridgedSourceLoc cAsyncLoc, BridgedSourceLoc cThrowsLoc,
-    BridgedNullableTypeRepr thrownType, BridgedSourceLoc cArrowLoc,
+    swift::SourceLoc asyncLoc, swift::SourceLoc throwsLoc,
+    BridgedNullableTypeRepr thrownType, swift::SourceLoc arrowLoc,
     BridgedTypeRepr resultType);
 
 SWIFT_NAME("BridgedUnqualifiedIdentTypeRepr.createParsed(_:name:nameLoc:"
            "genericArgs:leftAngleLoc:rightAngleLoc:)")
 BridgedUnqualifiedIdentTypeRepr BridgedUnqualifiedIdentTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedIdentifier name,
-    BridgedSourceLoc cNameLoc, BridgedArrayRef genericArgs,
-    BridgedSourceLoc cLAngleLoc, BridgedSourceLoc cRAngleLoc);
+    BridgedASTContext cContext, swift::Identifier name,
+    swift::SourceLoc nameLoc, BridgedArrayRef genericArgs,
+    swift::SourceLoc lAngleLoc, swift::SourceLoc rAngleLoc);
 
 SWIFT_NAME("BridgedOptionalTypeRepr.createParsed(_:base:questionLoc:)")
 BridgedOptionalTypeRepr
 BridgedOptionalTypeRepr_createParsed(BridgedASTContext cContext,
                                      BridgedTypeRepr base,
-                                     BridgedSourceLoc cQuestionLoc);
+                                     swift::SourceLoc questionLoc);
 
 SWIFT_NAME("BridgedImplicitlyUnwrappedOptionalTypeRepr.createParsed(_:base:"
            "exclaimLoc:)")
 BridgedImplicitlyUnwrappedOptionalTypeRepr
 BridgedImplicitlyUnwrappedOptionalTypeRepr_createParsed(
     BridgedASTContext cContext, BridgedTypeRepr base,
-    BridgedSourceLoc cExclamationLoc);
+    swift::SourceLoc exclamationLoc);
 
 SWIFT_NAME("BridgedInlineArrayTypeRepr.createParsed(_:count:element:brackets:)")
 BridgedInlineArrayTypeRepr BridgedInlineArrayTypeRepr_createParsed(
     BridgedASTContext cContext, BridgedTypeRepr cCountType,
-    BridgedTypeRepr cElementType, BridgedSourceRange cBracketsRange);
+    BridgedTypeRepr cElementType, swift::SourceRange bracketsRange);
 
 SWIFT_NAME("BridgedInverseTypeRepr.createParsed(_:tildeLoc:constraint:)")
 BridgedInverseTypeRepr
 BridgedInverseTypeRepr_createParsed(BridgedASTContext cContext,
-                                    BridgedSourceLoc cTildeLoc,
+                                    swift::SourceLoc tildeLoc,
                                     BridgedTypeRepr cConstraint);
 
 SWIFT_NAME("BridgedIsolatedTypeRepr.createParsed(_:base:specifierLoc:)")
 BridgedIsolatedTypeRepr
 BridgedIsolatedTypeRepr_createParsed(BridgedASTContext cContext,
                                      BridgedTypeRepr base,
-                                     BridgedSourceLoc cSpecifierLoc);
+                                     swift::SourceLoc specifierLoc);
 
 SWIFT_NAME("BridgedLifetimeDependentTypeRepr.createParsed(_:base:entry:)")
 BridgedLifetimeDependentTypeRepr
@@ -2738,49 +2601,53 @@ SWIFT_NAME("BridgedMetatypeTypeRepr.createParsed(_:base:typeKeywordLoc:)")
 BridgedMetatypeTypeRepr
 BridgedMetatypeTypeRepr_createParsed(BridgedASTContext cContext,
                                      BridgedTypeRepr baseType,
-                                     BridgedSourceLoc cTypeLoc);
+                                     swift::SourceLoc typeLoc);
 
 SWIFT_NAME(
     "BridgedOwnershipTypeRepr.createParsed(_:base:specifier:specifierLoc:)")
 BridgedOwnershipTypeRepr BridgedOwnershipTypeRepr_createParsed(
     BridgedASTContext cContext, BridgedTypeRepr base,
-    BridgedParamSpecifier cSpecifier, BridgedSourceLoc cSpecifierLoc);
+    BridgedParamSpecifier cSpecifier, swift::SourceLoc specifierLoc);
 
 SWIFT_NAME("BridgedPlaceholderTypeRepr.createParsed(_:loc:)")
 BridgedPlaceholderTypeRepr
 BridgedPlaceholderTypeRepr_createParsed(BridgedASTContext cContext,
-                                        BridgedSourceLoc cLoc);
+                                        swift::SourceLoc loc);
 
 SWIFT_NAME("BridgedProtocolTypeRepr.createParsed(_:base:protocolKeywordLoc:)")
 BridgedProtocolTypeRepr
 BridgedProtocolTypeRepr_createParsed(BridgedASTContext cContext,
                                      BridgedTypeRepr baseType,
-                                     BridgedSourceLoc cProtoLoc);
+                                     swift::SourceLoc protoLoc);
 
 SWIFT_NAME("BridgedPackElementTypeRepr.createParsed(_:base:eachKeywordLoc:)")
-BridgedPackElementTypeRepr
-BridgedPackElementTypeRepr_createParsed(BridgedASTContext cContext,
-                                        BridgedTypeRepr base,
-                                        BridgedSourceLoc cEachLoc);
+BridgedPackElementTypeRepr BridgedPackElementTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr base, swift::SourceLoc eachLoc);
 
 SWIFT_NAME(
     "BridgedPackExpansionTypeRepr.createParsed(_:base:repeatKeywordLoc:)")
 BridgedPackExpansionTypeRepr
 BridgedPackExpansionTypeRepr_createParsed(BridgedASTContext cContext,
                                           BridgedTypeRepr base,
-                                          BridgedSourceLoc cRepeatLoc);
+                                          swift::SourceLoc repeatLoc);
 
 SWIFT_NAME("BridgedSendingTypeRepr.createParsed(_:base:specifierLoc:)")
 BridgedSendingTypeRepr
 BridgedSendingTypeRepr_createParsed(BridgedASTContext cContext,
                                     BridgedTypeRepr base,
-                                    BridgedSourceLoc cSpecifierLoc);
+                                    swift::SourceLoc specifierLoc);
+
+SWIFT_NAME("BridgedCallerIsolatedTypeRepr.createParsed(_:base:specifierLoc:)")
+BridgedCallerIsolatedTypeRepr
+BridgedCallerIsolatedTypeRepr_createParsed(BridgedASTContext cContext,
+                                           BridgedTypeRepr base,
+                                           swift::SourceLoc specifierLoc);
 
 SWIFT_NAME(
     "BridgedTupleTypeRepr.createParsed(_:elements:leftParenLoc:rightParenLoc:)")
 BridgedTupleTypeRepr BridgedTupleTypeRepr_createParsed(
     BridgedASTContext cContext, BridgedArrayRef elements,
-    BridgedSourceLoc cLParenLoc, BridgedSourceLoc cRParenLoc);
+    swift::SourceLoc lParenLoc, swift::SourceLoc rParenLoc);
 
 SWIFT_NAME(
     "BridgedNamedOpaqueReturnTypeRepr.createParsed(_:base:genericParamList:)")
@@ -2791,26 +2658,26 @@ BridgedNamedOpaqueReturnTypeRepr BridgedNamedOpaqueReturnTypeRepr_createParsed(
 SWIFT_NAME("BridgedOpaqueReturnTypeRepr.createParsed(_:someKeywordLoc:base:)")
 BridgedOpaqueReturnTypeRepr
 BridgedOpaqueReturnTypeRepr_createParsed(BridgedASTContext cContext,
-                                         BridgedSourceLoc cOpaqueLoc,
+                                         swift::SourceLoc opaqueLoc,
                                          BridgedTypeRepr baseTy);
 
 SWIFT_NAME("BridgedExistentialTypeRepr.createParsed(_:anyKeywordLoc:base:)")
 BridgedExistentialTypeRepr
 BridgedExistentialTypeRepr_createParsed(BridgedASTContext cContext,
-                                        BridgedSourceLoc cAnyLoc,
+                                        swift::SourceLoc anyLoc,
                                         BridgedTypeRepr baseTy);
 
 SWIFT_NAME("BridgedVarargTypeRepr.createParsed(_:base:ellipsisLoc:)")
 BridgedVarargTypeRepr
 BridgedVarargTypeRepr_createParsed(BridgedASTContext cContext,
                                    BridgedTypeRepr base,
-                                   BridgedSourceLoc cEllipsisLoc);
+                                   swift::SourceLoc ellipsisLoc);
 
 SWIFT_NAME(
     "BridgedIntegerTypeRepr.createParsed(_:string:loc:minusLoc:)")
 BridgedIntegerTypeRepr BridgedIntegerTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedStringRef cString, BridgedSourceLoc cLoc,
-    BridgedSourceLoc cMinusLoc);
+    BridgedASTContext cContext, BridgedStringRef cString, swift::SourceLoc loc,
+    swift::SourceLoc minusLoc);
 
 SWIFT_NAME("BridgedTypeRepr.dump(self:)")
 void BridgedTypeRepr_dump(BridgedTypeRepr type);
@@ -2824,7 +2691,7 @@ BridgedNullableVarDecl BridgedPattern_getSingleVar(BridgedPattern cPattern);
 
 SWIFT_NAME("BridgedAnyPattern.createParsed(_:loc:)")
 BridgedAnyPattern BridgedAnyPattern_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cLoc);
+                                                 swift::SourceLoc loc);
 
 SWIFT_NAME("BridgedAnyPattern.createImplicit(_:)")
 BridgedAnyPattern BridgedAnyPattern_createImplicit(BridgedASTContext cContext);
@@ -2832,13 +2699,13 @@ BridgedAnyPattern BridgedAnyPattern_createImplicit(BridgedASTContext cContext);
 SWIFT_NAME("BridgedBindingPattern.createParsed(_:keywordLoc:isLet:subPattern:)")
 BridgedBindingPattern
 BridgedBindingPattern_createParsed(BridgedASTContext cContext,
-                                   BridgedSourceLoc cKeywordLoc, bool isLet,
+                                   swift::SourceLoc keywordLoc, bool isLet,
                                    BridgedPattern cSubPattern);
 
 SWIFT_NAME("BridgedBindingPattern.createImplicitCatch(_:loc:)")
 BridgedBindingPattern
 BridgedBindingPattern_createImplicitCatch(BridgedDeclContext cDeclContext,
-                                          BridgedSourceLoc cLoc);
+                                          swift::SourceLoc loc);
 
 SWIFT_NAME("BridgedExprPattern.createParsed(_:expr:)")
 BridgedExprPattern
@@ -2847,31 +2714,31 @@ BridgedExprPattern_createParsed(BridgedDeclContext cDeclContext,
 
 SWIFT_NAME("BridgedIsPattern.createParsed(_:isLoc:typeExpr:)")
 BridgedIsPattern BridgedIsPattern_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cIsLoc,
+                                               swift::SourceLoc isLoc,
                                                BridgedTypeExpr cTypeExpr);
 
 SWIFT_NAME("BridgedNamedPattern.createParsed(_:declContext:name:loc:)")
 BridgedNamedPattern
 BridgedNamedPattern_createParsed(BridgedASTContext astContext,
                                  BridgedDeclContext declContext,
-                                 BridgedIdentifier name, BridgedSourceLoc cLoc);
+                                 swift::Identifier name, swift::SourceLoc loc);
 
 SWIFT_NAME(
     "BridgedParenPattern.createParsed(_:lParenLoc:subPattern:rParenLoc:)")
 BridgedParenPattern BridgedParenPattern_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLParenLoc,
-    BridgedPattern cSubPattern, BridgedSourceLoc cRParenLoc);
+    BridgedASTContext cContext, swift::SourceLoc lParenLoc,
+    BridgedPattern cSubPattern, swift::SourceLoc rParenLoc);
 
 struct BridgedTuplePatternElt {
-  BridgedIdentifier Label;
-  BridgedSourceLoc LabelLoc;
+  swift::Identifier Label;
+  swift::SourceLoc LabelLoc;
   BridgedPattern ThePattern;
 };
 
 SWIFT_NAME("BridgedTuplePattern.createParsed(_:lParenLoc:elements:rParenLoc:)")
 BridgedTuplePattern BridgedTuplePattern_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLParenLoc,
-    BridgedArrayRef cElements, BridgedSourceLoc cRParenLoc);
+    BridgedASTContext cContext, swift::SourceLoc lParenLoc,
+    BridgedArrayRef cElements, swift::SourceLoc rParenLoc);
 
 SWIFT_NAME("BridgedTypedPattern.createParsed(_:pattern:type:)")
 BridgedTypedPattern BridgedTypedPattern_createParsed(BridgedASTContext cContext,
@@ -2886,25 +2753,12 @@ SWIFT_NAME("BridgedPattern.setImplicit(self:)")
 void BridgedPattern_setImplicit(BridgedPattern cPattern);
 
 SWIFT_NAME("getter:BridgedPattern.boundName(self:)")
-BridgedIdentifier BridgedPattern_getBoundName(BridgedPattern cPattern);
+swift::Identifier BridgedPattern_getBoundName(BridgedPattern cPattern);
 
 //===----------------------------------------------------------------------===//
 // MARK: Generics
 //===----------------------------------------------------------------------===//
 
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedLayoutConstraintKind {
-  BridgedLayoutConstraintKindUnknownLayout,
-  BridgedLayoutConstraintKindTrivialOfExactSize,
-  BridgedLayoutConstraintKindTrivialOfAtMostSize,
-  BridgedLayoutConstraintKindTrivial,
-  BridgedLayoutConstraintKindClass,
-  BridgedLayoutConstraintKindNativeClass,
-  BridgedLayoutConstraintKindRefCountedObject,
-  BridgedLayoutConstraintKindNativeRefCountedObject,
-  BridgedLayoutConstraintKindBridgeObject,
-  BridgedLayoutConstraintKindTrivialStride,
-};
-
 class BridgedLayoutConstraint {
   swift::LayoutConstraintInfo *_Nullable raw;
 
@@ -2915,55 +2769,49 @@ class BridgedLayoutConstraint {
   SWIFT_UNAVAILABLE("Use the factory methods")
   BRIDGED_INLINE BridgedLayoutConstraint(swift::LayoutConstraint constraint);
 
+  BRIDGED_INLINE
+  SWIFT_COMPUTED_PROPERTY
+  bool getIsNull() const;
+
+  SWIFT_COMPUTED_PROPERTY
+  swift::LayoutConstraintKind getKind() const;
+
+  BRIDGED_INLINE
+  SWIFT_COMPUTED_PROPERTY
+  bool getIsKnownLayout() const;
+
+  BRIDGED_INLINE
+  SWIFT_COMPUTED_PROPERTY
+  bool getIsTrivial() const;
+
+  SWIFT_UNAVAILABLE("Unavailable in Swift")
   BRIDGED_INLINE swift::LayoutConstraint unbridged() const;
 };
 
 SWIFT_NAME("BridgedLayoutConstraint.getLayoutConstraint(_:id:)")
 BridgedLayoutConstraint
 BridgedLayoutConstraint_getLayoutConstraint(BridgedASTContext cContext,
-                                            BridgedIdentifier cID);
+                                            swift::Identifier ID);
 
 SWIFT_NAME("BridgedLayoutConstraint.getLayoutConstraint(_:kind:)")
 BridgedLayoutConstraint
 BridgedLayoutConstraint_getLayoutConstraint(BridgedASTContext cContext,
-                                            BridgedLayoutConstraintKind cKind);
+                                            swift::LayoutConstraintKind kind);
 
 SWIFT_NAME(
     "BridgedLayoutConstraint.getLayoutConstraint(_:kind:size:alignment:)")
 BridgedLayoutConstraint
 BridgedLayoutConstraint_getLayoutConstraint(BridgedASTContext cContext,
-                                            BridgedLayoutConstraintKind cKind,
+                                            swift::LayoutConstraintKind kind,
                                             size_t size, size_t alignment);
 
-SWIFT_NAME("getter:BridgedLayoutConstraint.isNull(self:)")
-BRIDGED_INLINE bool
-BridgedLayoutConstraint_isNull(BridgedLayoutConstraint cConstraint);
-
-SWIFT_NAME("getter:BridgedLayoutConstraint.kind(self:)")
-BridgedLayoutConstraintKind
-BridgedLayoutConstraint_getKind(BridgedLayoutConstraint cConstraint);
-
-SWIFT_NAME("getter:BridgedLayoutConstraint.isKnownLayout(self:)")
-BRIDGED_INLINE bool
-BridgedLayoutConstraint_isKnownLayout(BridgedLayoutConstraint cConstraint);
-
-SWIFT_NAME("getter:BridgedLayoutConstraint.isTrivial(self:)")
-BRIDGED_INLINE bool
-BridgedLayoutConstraint_isTrivial(BridgedLayoutConstraint cConstraint);
-
-enum ENUM_EXTENSIBILITY_ATTR(open) BridgedRequirementReprKind : size_t {
-  BridgedRequirementReprKindTypeConstraint,
-  BridgedRequirementReprKindSameType,
-  BridgedRequirementReprKindLayoutConstraint,
-};
-
 struct BridgedRequirementRepr {
-  BridgedSourceLoc SeparatorLoc;
-  BridgedRequirementReprKind Kind;
+  swift::SourceLoc SeparatorLoc;
+  swift::RequirementReprKind Kind;
   BridgedTypeRepr FirstType;
   BridgedNullableTypeRepr SecondType;
   BridgedLayoutConstraint LayoutConstraint;
-  BridgedSourceLoc LayoutConstraintLoc;
+  swift::SourceLoc LayoutConstraintLoc;
   bool IsExpansionPattern;
 
   swift::RequirementRepr unbridged() const;
@@ -2972,58 +2820,49 @@ struct BridgedRequirementRepr {
 SWIFT_NAME("BridgedRequirementRepr.createTypeConstraint(subject:colonLoc:"
            "constraint:isExpansionPattern:)")
 BridgedRequirementRepr BridgedRequirementRepr_createTypeConstraint(
-    BridgedTypeRepr cSubject, BridgedSourceLoc cColonLoc,
+    BridgedTypeRepr cSubject, swift::SourceLoc colonLoc,
     BridgedTypeRepr cConstraint, bool isExpansionPattern);
 SWIFT_NAME("BridgedRequirementRepr.createSameType(firstType:equalLoc:"
            "secondType:isExpansionPattern:)")
 BridgedRequirementRepr BridgedRequirementRepr_createSameType(
-    BridgedTypeRepr cFirstType, BridgedSourceLoc cEqualLoc,
+    BridgedTypeRepr cFirstType, swift::SourceLoc equalLoc,
     BridgedTypeRepr cSecondType, bool isExpansionPattern);
 SWIFT_NAME("BridgedRequirementRepr.createLayoutConstraint(subject:colonLoc:"
            "layout:layoutLoc:isExpansionPattern:)")
 BridgedRequirementRepr BridgedRequirementRepr_createLayoutConstraint(
-    BridgedTypeRepr cSubject, BridgedSourceLoc cColonLoc,
-    BridgedLayoutConstraint cLayout, BridgedSourceLoc cLayoutLoc,
+    BridgedTypeRepr cSubject, swift::SourceLoc colonLoc,
+    BridgedLayoutConstraint cLayout, swift::SourceLoc layoutLoc,
     bool isExpansionPattern);
 
-enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedGenericTypeParamKind : size_t {
-  /// A regular generic type parameter: 'T'
-  BridgedGenericTypeParamKindType = 0,
-  /// A generic parameter pack: 'each T'
-  BridgedGenericTypeParamKindPack,
-  /// A generic value parameter: 'let T'
-  BridgedGenericTypeParamKindValue,
-};
-
 SWIFT_NAME("BridgedGenericParamList.createParsed(_:leftAngleLoc:parameters:"
            "genericWhereClause:rightAngleLoc:)")
 BridgedGenericParamList BridgedGenericParamList_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLeftAngleLoc,
+    BridgedASTContext cContext, swift::SourceLoc leftAngleLoc,
     BridgedArrayRef cParameters,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceLoc cRightAngleLoc);
+    swift::SourceLoc rightAngleLoc);
 
 SWIFT_NAME(
     "BridgedGenericTypeParamDecl.createParsed(_:declContext:specifierLoc:"
     "name:nameLoc:inheritedType:index:paramKind:)")
 BridgedGenericTypeParamDecl BridgedGenericTypeParamDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cSpecifierLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableTypeRepr opaqueInheritedType,
-    size_t index, BridgedGenericTypeParamKind paramKind);
+    swift::SourceLoc specifierLoc, swift::Identifier name,
+    swift::SourceLoc nameLoc, BridgedNullableTypeRepr opaqueInheritedType,
+    size_t index, swift::GenericTypeParamKind paramKind);
 
 SWIFT_NAME(
     "BridgedTrailingWhereClause.createParsed(_:whereKeywordLoc:requirements:)")
 BridgedTrailingWhereClause
 BridgedTrailingWhereClause_createParsed(BridgedASTContext cContext,
-                                        BridgedSourceLoc cWhereKeywordLoc,
+                                        swift::SourceLoc whereKeywordLoc,
                                         BridgedArrayRef cRequirements);
 
 SWIFT_NAME("BridgedParameterList.createParsed(_:leftParenLoc:parameters:"
            "rightParenLoc:)")
 BridgedParameterList BridgedParameterList_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLeftParenLoc,
-    BridgedArrayRef cParameters, BridgedSourceLoc cRightParenLoc);
+    BridgedASTContext cContext, swift::SourceLoc leftParenLoc,
+    BridgedArrayRef cParameters, swift::SourceLoc rightParenLoc);
 
 SWIFT_NAME("getter:BridgedParameterList.size(self:)")
 size_t BridgedParameterList_size(BridgedParameterList cParameterList);
@@ -3037,14 +2876,14 @@ BridgedParamDecl BridgedParameterList_get(BridgedParameterList cParameterList,
 //===----------------------------------------------------------------------===//
 
 struct BridgedTupleTypeElement {
-  BridgedIdentifier Name;
-  BridgedSourceLoc NameLoc;
-  BridgedIdentifier SecondName;
-  BridgedSourceLoc SecondNameLoc;
-  BridgedSourceLoc UnderscoreLoc;
-  BridgedSourceLoc ColonLoc;
+  swift::Identifier Name;
+  swift::SourceLoc NameLoc;
+  swift::Identifier SecondName;
+  swift::SourceLoc SecondNameLoc;
+  swift::SourceLoc UnderscoreLoc;
+  swift::SourceLoc ColonLoc;
   BridgedTypeRepr Type;
-  BridgedSourceLoc TrailingCommaLoc;
+  swift::SourceLoc TrailingCommaLoc;
 };
 
 enum ENUM_EXTENSIBILITY_ATTR(open) BridgedMacroDefinitionKind : size_t {
@@ -3057,8 +2896,6 @@ enum ENUM_EXTENSIBILITY_ATTR(open) BridgedMacroDefinitionKind : size_t {
   BridgedBuiltinExternalMacro,
   /// The builtin definition for the "isolation" macro.
   BridgedBuiltinIsolationMacro,
-  /// The builtin definition for the "SwiftSetting" macro.
-  BridgedBuiltinSwiftSettingsMacro,
 };
 
 struct BridgedASTType {
@@ -3079,16 +2916,21 @@ struct BridgedASTType {
   BRIDGED_INLINE swift::Type unbridged() const;
   BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType getCanonicalType() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDiagnosticArgument asDiagnosticArgument() const;
   BRIDGED_INLINE bool hasArchetype() const;
   BRIDGED_INLINE bool isLegalFormalType() const;
   BRIDGED_INLINE bool isGenericAtAnyLevel() const;
   BRIDGED_INLINE bool hasTypeParameter() const;
   BRIDGED_INLINE bool hasLocalArchetype() const;
+  BRIDGED_INLINE bool hasDynamicSelf() const;
+  BRIDGED_INLINE bool isArchetype() const;
+  BRIDGED_INLINE bool archetypeRequiresClass() const;
   BRIDGED_INLINE bool isExistentialArchetype() const;
   BRIDGED_INLINE bool isExistentialArchetypeWithError() const;
   BRIDGED_INLINE bool isExistential() const;
   BRIDGED_INLINE bool isDynamicSelf() const;
   BRIDGED_INLINE bool isClassExistential() const;
+  BRIDGED_INLINE bool isGenericTypeParam() const;
   BRIDGED_INLINE bool isEscapable() const;
   BRIDGED_INLINE bool isNoEscape() const;
   BRIDGED_INLINE bool isInteger() const;
@@ -3105,19 +2947,26 @@ struct BridgedASTType {
   BRIDGED_INLINE bool isBuiltinInteger() const;
   BRIDGED_INLINE bool isBuiltinFloat() const;
   BRIDGED_INLINE bool isBuiltinVector() const;
+  BRIDGED_INLINE bool isBuiltinFixedArray() const;
+  BRIDGED_INLINE bool isBox() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType getBuiltinVectorElementType() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType getBuiltinFixedArrayElementType() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType getBuiltinFixedArraySizeType() const;
   BRIDGED_INLINE bool isBuiltinFixedWidthInteger(SwiftInt width) const;
   BRIDGED_INLINE bool isOptional() const;
+  BRIDGED_INLINE bool isBuiltinType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDeclObj getNominalOrBoundGenericNominal() const;
   BRIDGED_INLINE TraitResult canBeClass() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDeclObj getAnyNominal() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType getInstanceTypeOfMetatype() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType getStaticTypeOfDynamicSelf() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType getInterfaceTypeOfArchetype() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType getSuperClassType() const;
   BRIDGED_INLINE MetatypeRepresentation getRepresentationOfMetatype() const;
+  BRIDGED_INLINE BridgedOptionalInt getValueOfIntegerType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSubstitutionMap getContextSubstitutionMap() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedGenericSignature getInvocationGenericSignatureOfFunctionType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType subst(BridgedSubstitutionMap substMap) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType subst(BridgedASTType fromType, BridgedASTType toType) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedConformance checkConformance(BridgedDeclObj proto) const;  
 };
 
@@ -3125,6 +2974,7 @@ class BridgedCanType {
   swift::TypeBase * _Nullable type;
 
 public:
+  BRIDGED_INLINE BridgedCanType();
   BRIDGED_INLINE BridgedCanType(swift::CanType ty);
   BRIDGED_INLINE swift::CanType unbridged() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType getRawType() const;
@@ -3191,6 +3041,7 @@ struct BridgedGenericSignature {
   BRIDGED_INLINE swift::GenericSignature unbridged() const;
   BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTTypeArray getGenericParams() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType mapTypeIntoContext(BridgedASTType type) const;
 };
 
 struct BridgedFingerprint {
@@ -3222,9 +3073,9 @@ enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedIfConfigClauseKind : size_t {
 
 /// Bridged version of IfConfigClauseRangeInfo.
 struct BridgedIfConfigClauseRangeInfo {
-  BridgedSourceLoc directiveLoc;
-  BridgedSourceLoc bodyLoc;
-  BridgedSourceLoc endLoc;
+  swift::SourceLoc directiveLoc;
+  swift::SourceLoc bodyLoc;
+  swift::SourceLoc endLoc;
   BridgedIfConfigClauseKind kind;
 
   BRIDGED_INLINE swift::IfConfigClauseRangeInfo unbridged() const;
diff --git a/include/swift/AST/ASTBridgingImpl.h b/include/swift/AST/ASTBridgingImpl.h
index ac8d117cc9aef..b71a98e3b140d 100644
--- a/include/swift/AST/ASTBridgingImpl.h
+++ b/include/swift/AST/ASTBridgingImpl.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2023 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -20,6 +20,7 @@
 #include "swift/AST/Decl.h"
 #include "swift/AST/Expr.h"
 #include "swift/AST/GenericSignature.h"
+#include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/IfConfigClauseRangeInfo.h"
 #include "swift/AST/MacroDeclaration.h"
 #include "swift/AST/ProtocolConformance.h"
@@ -32,39 +33,12 @@
 SWIFT_BEGIN_NULLABILITY_ANNOTATIONS
 
 //===----------------------------------------------------------------------===//
-// MARK: BridgedIdentifier
-//===----------------------------------------------------------------------===//
-
-BridgedIdentifier::BridgedIdentifier(swift::Identifier ident)
-    : Raw(ident.getAsOpaquePointer()) {}
-
-swift::Identifier BridgedIdentifier::unbridged() const {
-  return swift::Identifier::getFromOpaquePointer(Raw);
-}
-
-bool BridgedIdentifier_isOperator(const BridgedIdentifier ident) {
-  return ident.unbridged().isOperator();
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: BridgedDeclBaseName
-//===----------------------------------------------------------------------===//
-
-BridgedDeclBaseName::BridgedDeclBaseName(swift::DeclBaseName baseName)
-  : Ident(baseName.Ident) {}
-
-swift::DeclBaseName BridgedDeclBaseName::unbridged() const {
-  return swift::DeclBaseName(Ident.unbridged());
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: BridgedDeclBaseName
+// MARK: BridgedConsumedLookupResult
 //===----------------------------------------------------------------------===//
 
 BridgedConsumedLookupResult::BridgedConsumedLookupResult(
     swift::Identifier name, swift::SourceLoc sourceLoc, SwiftInt flag)
-    : Name(BridgedIdentifier(name)), NameLoc(BridgedSourceLoc(sourceLoc)),
-      Flag(flag) {}
+    : Name(name), NameLoc(swift::SourceLoc(sourceLoc)), Flag(flag) {}
 
 //===----------------------------------------------------------------------===//
 // MARK: BridgedDeclNameRef
@@ -92,6 +66,17 @@ swift::DeclNameLoc BridgedDeclNameLoc::unbridged() const {
   return swift::DeclNameLoc(LocationInfo, NumArgumentLabels);
 }
 
+//===----------------------------------------------------------------------===//
+// MARK: BridgedLangOptions
+//===----------------------------------------------------------------------===//
+
+BridgedLangOptions::BridgedLangOptions(const swift::LangOptions &langOpts)
+  : LangOpts(&langOpts) { }
+
+const swift::LangOptions &BridgedLangOptions::unbridged() const {
+  return *LangOpts;
+}
+
 //===----------------------------------------------------------------------===//
 // MARK: BridgedASTContext
 //===----------------------------------------------------------------------===//
@@ -100,10 +85,6 @@ BridgedASTContext::BridgedASTContext(swift::ASTContext &ctx) : Ctx(&ctx) {}
 
 swift::ASTContext &BridgedASTContext::unbridged() const { return *Ctx; }
 
-void * _Nonnull BridgedASTContext_raw(BridgedASTContext bridged) {
-  return &bridged.unbridged();
-}
-
 BridgedASTContext BridgedASTContext_fromRaw(void * _Nonnull ptr) {
   return *static_cast<swift::ASTContext *>(ptr);
 }
@@ -118,10 +99,10 @@ BridgedStringRef BridgedASTContext_allocateCopyString(BridgedASTContext bridged,
   return bridged.unbridged().AllocateCopy(cStr.unbridged());
 }
 
-#define IDENTIFIER_WITH_NAME(Name, _) \
-BridgedIdentifier BridgedASTContext_id_##Name(BridgedASTContext bridged) { \
-return bridged.unbridged().Id_##Name; \
-}
+#define IDENTIFIER_WITH_NAME(Name, _)                                          \
+  swift::Identifier BridgedASTContext_id_##Name(BridgedASTContext bridged) {   \
+    return bridged.unbridged().Id_##Name;                                      \
+  }
 #include "swift/AST/KnownIdentifiers.def"
 
 //===----------------------------------------------------------------------===//
@@ -171,15 +152,18 @@ bool BridgedSourceFile_isScriptMode(BridgedSourceFile sf) {
 // MARK: BridgedDeclObj
 //===----------------------------------------------------------------------===//
 
-BridgedSourceLoc BridgedDeclObj::getLoc() const {
-  swift::SourceLoc sourceLoc = unbridged()->getLoc();
-  return BridgedSourceLoc(sourceLoc.getOpaquePointerValue());
+swift::SourceLoc BridgedDeclObj::getLoc() const {
+  return unbridged()->getLoc();
 }
 
 BridgedDeclObj BridgedDeclObj::getModuleContext() const {
   return {unbridged()->getModuleContext()};
 }
 
+OptionalBridgedDeclObj BridgedDeclObj::getParent() const {
+  return {unbridged()->getDeclContext()->getAsDecl()};
+}
+
 BridgedStringRef BridgedDeclObj::Type_getName() const {
   return getAs<swift::TypeDecl>()->getName().str();
 }
@@ -188,8 +172,8 @@ BridgedStringRef BridgedDeclObj::Value_getUserFacingName() const {
   return getAs<swift::ValueDecl>()->getBaseName().userFacingName();
 }
 
-BridgedSourceLoc BridgedDeclObj::Value_getNameLoc() const {
-  return BridgedSourceLoc(getAs<swift::ValueDecl>()->getNameLoc().getOpaquePointerValue());
+swift::SourceLoc BridgedDeclObj::Value_getNameLoc() const {
+  return getAs<swift::ValueDecl>()->getNameLoc();
 }
 
 bool BridgedDeclObj::hasClangNode() const {
@@ -216,6 +200,10 @@ OptionalBridgedDeclObj BridgedDeclObj::NominalType_getValueTypeDestructor() cons
   return {getAs<swift::NominalTypeDecl>()->getValueTypeDestructor()};
 }
 
+bool BridgedDeclObj::Enum_hasRawType() const {
+  return getAs<swift::EnumDecl>()->hasRawType();
+}
+
 bool BridgedDeclObj::Struct_hasUnreferenceableStorage() const {
   return getAs<swift::StructDecl>()->hasUnreferenceableStorage();
 }
@@ -228,6 +216,10 @@ BridgedDeclObj BridgedDeclObj::Class_getDestructor() const {
   return {getAs<swift::ClassDecl>()->getDestructor()};
 }
 
+bool BridgedDeclObj::ProtocolDecl_requiresClass() const {
+  return getAs<swift::ProtocolDecl>()->requiresClass();
+}
+
 bool BridgedDeclObj::AbstractFunction_isOverridden() const {
   return getAs<swift::AbstractFunctionDecl>()->isOverridden();
 }
@@ -238,6 +230,10 @@ bool BridgedDeclObj::Destructor_isIsolated() const {
   return ai.isActorIsolated();
 }
 
+bool BridgedDeclObj::EnumElementDecl_hasAssociatedValues() const {
+  return getAs<swift::EnumElementDecl>()->hasAssociatedValues();
+}
+
 //===----------------------------------------------------------------------===//
 // MARK: BridgedASTNode
 //===----------------------------------------------------------------------===//
@@ -314,7 +310,7 @@ bool BridgedAvailabilityDomainOrIdentifier_isDomain(
   return cVal.unbridged().isDomain();
 }
 
-BridgedIdentifier BridgedAvailabilityDomainOrIdentifier_getAsIdentifier(
+swift::Identifier BridgedAvailabilityDomainOrIdentifier_getAsIdentifier(
     BridgedAvailabilityDomainOrIdentifier cVal) {
   if (auto ident = cVal.unbridged().getAsIdentifier())
     return *ident;
@@ -378,8 +374,7 @@ BridgedVarDecl_asAbstractStorageDecl(BridgedVarDecl decl) {
 //===----------------------------------------------------------------------===//
 
 swift::Argument BridgedCallArgument::unbridged() const {
-  return swift::Argument(labelLoc.unbridged(), label.unbridged(),
-                         argExpr.unbridged());
+  return swift::Argument(labelLoc, label, argExpr.unbridged());
 }
 
 //===----------------------------------------------------------------------===//
@@ -387,7 +382,7 @@ swift::Argument BridgedCallArgument::unbridged() const {
 //===----------------------------------------------------------------------===//
 
 swift::LabeledStmtInfo BridgedLabeledStmtInfo::unbridged() const {
-  return {Name.unbridged(), Loc.unbridged()};
+  return {Name, Loc};
 }
 
 //===----------------------------------------------------------------------===//
@@ -402,6 +397,10 @@ BridgedCanType BridgedASTType::getCanonicalType() const {
   return unbridged()->getCanonicalType();
 }
 
+BridgedDiagnosticArgument BridgedASTType::asDiagnosticArgument() const {
+  return swift::DiagnosticArgument(unbridged());
+}
+
 bool BridgedASTType::hasArchetype() const {
   return unbridged()->hasArchetype();
 }
@@ -423,6 +422,18 @@ bool BridgedASTType::hasLocalArchetype() const {
   return unbridged()->hasLocalArchetype();
 }
 
+bool BridgedASTType::hasDynamicSelf() const {
+  return unbridged()->hasDynamicSelfType();
+}
+
+bool BridgedASTType::isArchetype() const {
+  return unbridged()->is<swift::ArchetypeType>();
+}
+
+bool BridgedASTType::archetypeRequiresClass() const {
+  return unbridged()->castTo<swift::ArchetypeType>()->requiresClass();
+}
+
 bool BridgedASTType::isExistentialArchetype() const {
   return unbridged()->is<swift::ExistentialArchetypeType>();
 }
@@ -443,6 +454,10 @@ bool BridgedASTType::isClassExistential() const {
   return unbridged()->isClassExistentialType();
 }
 
+bool BridgedASTType::isGenericTypeParam() const {
+  return unbridged()->is<swift::GenericTypeParamType>();
+}
+
 bool BridgedASTType::isEscapable() const {
   return unbridged()->isEscapable();
 }
@@ -513,10 +528,26 @@ bool BridgedASTType::isBuiltinVector() const {
   return unbridged()->is<swift::BuiltinVectorType>();
 }
 
+bool BridgedASTType::isBuiltinFixedArray() const {
+  return unbridged()->is<swift::BuiltinFixedArrayType>();
+}
+
+bool BridgedASTType::isBox() const {
+  return unbridged()->is<swift::SILBoxType>();
+}
+
 BridgedASTType BridgedASTType::getBuiltinVectorElementType() const {
   return {unbridged()->castTo<swift::BuiltinVectorType>()->getElementType().getPointer()};
 }
 
+BridgedCanType BridgedASTType::getBuiltinFixedArrayElementType() const {
+  return unbridged()->castTo<swift::BuiltinFixedArrayType>()->getElementType();
+}
+
+BridgedCanType BridgedASTType::getBuiltinFixedArraySizeType() const {
+  return unbridged()->castTo<swift::BuiltinFixedArrayType>()->getSize();
+}
+
 bool BridgedASTType::isBuiltinFixedWidthInteger(SwiftInt width) const {
   if (auto *intTy = unbridged()->getAs<swift::BuiltinIntegerType>())
     return intTy->isFixedWidth((unsigned)width);
@@ -531,6 +562,10 @@ bool BridgedASTType::isUnownedStorageType() const {
   return unbridged()->is<swift::UnownedStorageType>();
 }
 
+bool BridgedASTType::isBuiltinType() const {
+  return unbridged()->isBuiltinType();
+}
+
 OptionalBridgedDeclObj BridgedASTType::getNominalOrBoundGenericNominal() const {
   return {unbridged()->getNominalOrBoundGenericNominal()};
 }
@@ -547,6 +582,14 @@ BridgedASTType BridgedASTType::getInstanceTypeOfMetatype() const {
   return {unbridged()->getAs<swift::AnyMetatypeType>()->getInstanceType().getPointer()};
 }
 
+BridgedASTType BridgedASTType::getStaticTypeOfDynamicSelf() const {
+  return {unbridged()->getAs<swift::DynamicSelfType>()->getSelfType().getPointer()};
+}
+
+BridgedASTType BridgedASTType::getInterfaceTypeOfArchetype() const {
+  return {unbridged()->getAs<swift::ArchetypeType>()->getInterfaceType().getPointer()};
+}
+
 BridgedASTType BridgedASTType::getSuperClassType() const {
   return {unbridged()->getSuperclass().getPointer()};
 }
@@ -555,6 +598,10 @@ BridgedASTType::MetatypeRepresentation BridgedASTType::getRepresentationOfMetaty
   return MetatypeRepresentation(unbridged()->getAs<swift::AnyMetatypeType>()->getRepresentation());
 }
 
+BridgedOptionalInt BridgedASTType::getValueOfIntegerType() const {
+  return getFromAPInt(unbridged()->getAs<swift::IntegerType>()->getValue());
+}
+
 BridgedSubstitutionMap BridgedASTType::getContextSubstitutionMap() const {
   return unbridged()->getContextSubstitutionMap();
 }
@@ -567,17 +614,6 @@ BridgedASTType BridgedASTType::subst(BridgedSubstitutionMap substMap) const {
   return {unbridged().subst(substMap.unbridged()).getPointer()};
 }
 
-
-BridgedASTType BridgedASTType::subst(BridgedASTType fromType, BridgedASTType toType) const {
-  auto *fromTy = fromType.unbridged()->castTo<swift::SubstitutableType>();
-  swift::Type toTy = toType.unbridged();
-  return {unbridged().subst([fromTy, toTy](swift::SubstitutableType *t) -> swift::Type {
-    if (t == fromTy)
-      return toTy;
-    return t;
-  }, swift::LookUpConformanceInModule(), swift::SubstFlags::SubstituteLocalArchetypes).getPointer()};
-}
-
 BridgedConformance BridgedASTType::checkConformance(BridgedDeclObj proto) const {
   return swift::checkConformance(unbridged(), proto.getAs<swift::ProtocolDecl>(), /*allowMissing=*/ false);
 }  
@@ -594,6 +630,9 @@ static_assert((int)BridgedASTType::MetatypeRepresentation::ObjC == (int)swift::M
 // MARK: BridgedCanType
 //===----------------------------------------------------------------------===//
 
+BridgedCanType::BridgedCanType() : type(nullptr) {
+}
+
 BridgedCanType::BridgedCanType(swift::CanType ty) : type(ty.getPointer()) {
 }
 
@@ -690,17 +729,14 @@ swift::LayoutConstraint BridgedLayoutConstraint::unbridged() const {
   return raw;
 }
 
-bool BridgedLayoutConstraint_isNull(BridgedLayoutConstraint cConstraint) {
-  return cConstraint.unbridged().isNull();
-}
+bool BridgedLayoutConstraint::getIsNull() const { return unbridged().isNull(); }
 
-bool BridgedLayoutConstraint_isKnownLayout(
-    BridgedLayoutConstraint cConstraint) {
-  return cConstraint.unbridged()->isKnownLayout();
+bool BridgedLayoutConstraint::getIsKnownLayout() const {
+  return unbridged()->isKnownLayout();
 }
 
-bool BridgedLayoutConstraint_isTrivial(BridgedLayoutConstraint cConstraint) {
-  return cConstraint.unbridged()->isTrivial();
+bool BridgedLayoutConstraint::getIsTrivial() const {
+  return unbridged()->isTrivial();
 }
 
 //===----------------------------------------------------------------------===//
@@ -795,6 +831,10 @@ BridgedASTTypeArray BridgedGenericSignature::getGenericParams() const {
   return {unbridged().getGenericParams()};
 }
 
+BridgedASTType BridgedGenericSignature::mapTypeIntoContext(BridgedASTType type) const {
+  return {unbridged().getGenericEnvironment()->mapTypeIntoContext(type.unbridged()).getPointer()};
+}
+
 //===----------------------------------------------------------------------===//
 // MARK: BridgedFingerprint
 //===----------------------------------------------------------------------===//
@@ -823,9 +863,7 @@ swift::IfConfigClauseRangeInfo BridgedIfConfigClauseRangeInfo::unbridged() const
     break;
   }
 
-  return swift::IfConfigClauseRangeInfo(directiveLoc.unbridged(),
-                                        bodyLoc.unbridged(),
-                                        endLoc.unbridged(),
+  return swift::IfConfigClauseRangeInfo(directiveLoc, bodyLoc, endLoc,
                                         clauseKind);
 }
 
@@ -855,7 +893,7 @@ BridgedRegexLiteralPatternFeature::BridgedRegexLiteralPatternFeature(
 
 BridgedRegexLiteralPatternFeature::UnbridgedTy
 BridgedRegexLiteralPatternFeature::unbridged() const {
-  return UnbridgedTy(Kind.unbridged(), Range.unbridged());
+  return UnbridgedTy(Kind.unbridged(), Range);
 }
 
 BridgedRegexLiteralPatternFeatures::UnbridgedTy
@@ -885,8 +923,8 @@ swift::CaptureListEntry BridgedCaptureListEntry::unbridged() const {
   return swift::CaptureListEntry(PBD);
 }
 
-BridgedVarDecl BridegedCaptureListEntry_getVar(BridgedCaptureListEntry entry) {
-  return entry.unbridged().getVar();
+BridgedVarDecl BridgedCaptureListEntry::getVarDecl() const {
+  return unbridged().getVar();
 }
 
 //===----------------------------------------------------------------------===//
@@ -894,13 +932,13 @@ BridgedVarDecl BridegedCaptureListEntry_getVar(BridgedCaptureListEntry entry) {
 //===----------------------------------------------------------------------===//
 
 void BridgedFloatLiteralExpr_setNegative(BridgedFloatLiteralExpr cExpr,
-                                         BridgedSourceLoc cLoc) {
-  cExpr.unbridged()->setNegative(cLoc.unbridged());
+                                         swift::SourceLoc loc) {
+  cExpr.unbridged()->setNegative(loc);
 }
 
 void BridgedIntegerLiteralExpr_setNegative(BridgedIntegerLiteralExpr cExpr,
-                                           BridgedSourceLoc cLoc) {
-  cExpr.unbridged()->setNegative(cLoc.unbridged());
+                                           swift::SourceLoc loc) {
+  cExpr.unbridged()->setNegative(loc);
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/include/swift/AST/ASTContext.h b/include/swift/AST/ASTContext.h
index e980d009d73f5..858e28d7dfc29 100644
--- a/include/swift/AST/ASTContext.h
+++ b/include/swift/AST/ASTContext.h
@@ -620,7 +620,7 @@ class ASTContext final {
   /// For example, if '-module-alias Foo=X -module-alias Bar=Y' input is passed in, the aliases Foo and Bar are
   /// the names of the imported or referenced modules in source files in the main module, and X and Y
   /// are the real (physical) module names on disk.
-  void setModuleAliases(const llvm::StringMap<StringRef> &aliasMap);
+  void setModuleAliases(const llvm::StringMap<std::string> &aliasMap);
 
   /// Adds a given alias to the map of Identifiers between module aliases and
   /// their actual names.
@@ -909,7 +909,7 @@ class ASTContext final {
   AvailabilityRange getSwiftAvailability(unsigned major, unsigned minor) const;
 
   // For each feature defined in FeatureAvailability, define two functions;
-  // the latter, with the suffix RuntimeAvailabilty, is for use with
+  // the latter, with the suffix RuntimeAvailability, is for use with
   // AvailabilityRange::forRuntimeTarget(), and only looks at the Swift
   // runtime version.
 #define FEATURE(N, V)                                                          \
@@ -1044,13 +1044,15 @@ class ASTContext final {
 
   // Builtin type and simple types that are used frequently.
   const CanType TheErrorType;             /// This is the ErrorType singleton.
-  const CanType TheUnresolvedType;        /// This is the UnresolvedType singleton.
   const CanType TheEmptyTupleType;        /// This is '()', aka Void
   const CanType TheEmptyPackType;
   const CanType TheAnyType;               /// This is 'Any', the empty protocol composition
   const CanType TheUnconstrainedAnyType;  /// This is 'any ~Copyable & ~Escapable',
                                           /// the empty protocol composition
                                           /// without any implicit constraints.
+  const CanGenericTypeParamType TheSelfType; /// The protocol 'Self' type;
+                                             /// a generic parameter with
+                                             /// depth 0 index 0
 #define SINGLETON_TYPE(SHORT_ID, ID) \
   const CanType The##SHORT_ID##Type;
 #include "swift/AST/TypeNodes.def"
@@ -1090,13 +1092,6 @@ class ASTContext final {
   /// Retrieve the module interface checker associated with this AST context.
   ModuleInterfaceChecker *getModuleInterfaceChecker() const;
 
-  /// Compute the extra implicit framework search paths on Apple platforms:
-  /// $SDKROOT/System/Library/Frameworks/ and $SDKROOT/Library/Frameworks/.
-  std::vector<std::string> getDarwinImplicitFrameworkSearchPaths() const;
-
-  /// Return a set of all possible filesystem locations where modules can be found.
-  llvm::StringSet<> getAllModuleSearchPathsSet() const;
-
   /// Load extensions to the given nominal type from the external
   /// module loaders.
   ///
@@ -1298,6 +1293,10 @@ class ASTContext final {
     return const_cast<ASTContext *>(this)->getStdlibModule(false);
   }
 
+  /// Names of underscored modules whose contents, if imported, should be
+  /// treated as separately-imported overlays of the standard library module.
+  ArrayRef<Identifier> StdlibOverlayNames;
+
   /// Insert an externally-sourced module into the set of known loaded modules
   /// in this context.
   void addLoadedModule(ModuleDecl *M);
@@ -1337,10 +1336,10 @@ class ASTContext final {
   getNormalConformance(Type conformingType,
                        ProtocolDecl *protocol,
                        SourceLoc loc,
+                       TypeRepr *inheritedTypeRepr,
                        DeclContext *dc,
                        ProtocolConformanceState state,
-                       ProtocolConformanceOptions options,
-                       SourceLoc preconcurrencyLoc = SourceLoc());
+                       ProtocolConformanceOptions options);
 
   /// Produce a self-conformance for the given protocol.
   SelfProtocolConformance *
@@ -1630,6 +1629,10 @@ class ASTContext final {
   AvailabilityDomain getTargetAvailabilityDomain() const;
 };
 
+inline SourceLoc extractNearestSourceLoc(const ASTContext *ctx) {
+  return SourceLoc();
+}
+
 } // end namespace swift
 
 #endif
diff --git a/include/swift/AST/ASTContextGlobalCache.h b/include/swift/AST/ASTContextGlobalCache.h
index 1925fe7885f03..e4aeb0415232f 100644
--- a/include/swift/AST/ASTContextGlobalCache.h
+++ b/include/swift/AST/ASTContextGlobalCache.h
@@ -55,6 +55,7 @@ struct WitnessIsolationError {
 /// Describes an isolation error involving an associated conformance.
 struct AssociatedConformanceIsolationError {
   ProtocolConformance *isolatedConformance;
+  DiagnosticBehavior behavior = DiagnosticBehavior::Unspecified;
 
   /// Diagnose this associated conformance isolation error.
   void diagnose(const NormalProtocolConformance *conformance) const;
@@ -83,6 +84,10 @@ struct ASTContext::GlobalCache {
     const NormalProtocolConformance *,
     std::vector<ConformanceIsolationError>
   > conformanceIsolationErrors;
+
+  /// The static build configuration. This points to an instance of the Swift
+  /// StaticBuildConfiguration.
+  void *StaticBuildConfiguration = nullptr;
 };
 
 } // end namespace 
diff --git a/include/swift/AST/ASTDemangler.h b/include/swift/AST/ASTDemangler.h
index 702072ddb3c83..58bcf68281a23 100644
--- a/include/swift/AST/ASTDemangler.h
+++ b/include/swift/AST/ASTDemangler.h
@@ -32,8 +32,10 @@
 #include <optional>
 
 namespace swift {
- 
+
+class Decl;
 class TypeDecl;
+class DeclName;
 
 namespace Demangle {
 SWIFT_BEGIN_INLINE_NAMESPACE
@@ -50,6 +52,9 @@ TypeDecl *getTypeDeclForUSR(ASTContext &ctx,
                             llvm::StringRef usr,
                             GenericSignature genericSig=GenericSignature());
 
+Decl *getDeclForUSR(ASTContext &ctx, llvm::StringRef usr,
+                    GenericSignature genericSig = GenericSignature());
+
 /// An implementation of MetadataReader's BuilderType concept that
 /// just finds and builds things in the AST.
 class ASTBuilder {
@@ -122,6 +127,17 @@ class ASTBuilder {
 
   Demangle::NodeFactory &getNodeFactory() { return Factory; }
 
+  /// Finds the \c Decl associated with the provided \p node.
+  /// Attempts to find a type declaration using \c createTypeDecl, if not found,
+  /// it performs a lookup for the declaration and returns the first declaration
+  /// for which \c isMatchingValueDecl returns true.
+  ///
+  /// \note \p isMatchingValueDecl is not evaluated for type declarations, it's
+  /// only used to choose among lookup results when \c createTypeDecl fails.
+  Decl *
+  findDecl(NodePointer node,
+           llvm::function_ref<bool(const ValueDecl *)> isMatchingValueDecl);
+
   Type decodeMangledType(NodePointer node, bool forRequirement = true);
   Type createBuiltinType(StringRef builtinName, StringRef mangledName);
 
@@ -142,6 +158,8 @@ class ASTBuilder {
 
   Type createBoundGenericType(GenericTypeDecl *decl, ArrayRef<Type> args);
   
+  OpaqueTypeDecl *resolveOpaqueTypeDecl(NodePointer opaqueDescriptor);
+
   Type resolveOpaqueType(NodePointer opaqueDescriptor,
                          ArrayRef<ArrayRef<Type>> args,
                          unsigned ordinal);
@@ -286,7 +304,8 @@ class ASTBuilder {
   /// The module name encoded in the node is either the module's real or ABI
   /// name. Multiple modules can share the same name. This function returns
   /// all modules that contain that name.
-  llvm::ArrayRef<ModuleDecl *> findPotentialModules(NodePointer node);
+  llvm::ArrayRef<ModuleDecl *> findPotentialModules(NodePointer node,
+                                                    ModuleDecl *&scratch);
 
   Demangle::NodePointer findModuleNode(NodePointer node);
 
diff --git a/include/swift/AST/ASTMangler.h b/include/swift/AST/ASTMangler.h
index 037cd4e4f732c..c4933fc4009fd 100644
--- a/include/swift/AST/ASTMangler.h
+++ b/include/swift/AST/ASTMangler.h
@@ -246,6 +246,8 @@ class ASTMangler : public Mangler {
   std::string mangleInitializerEntity(const VarDecl *var, SymbolKind SKind);
   std::string mangleBackingInitializerEntity(const VarDecl *var,
                                              SymbolKind SKind = SymbolKind::Default);
+  std::string manglePropertyWrappedFieldInitAccessorEntity(
+      const VarDecl *var, SymbolKind SKind = SymbolKind::Default);
   std::string mangleInitFromProjectedValueEntity(const VarDecl *var,
                                                  SymbolKind SKind = SymbolKind::Default);
 
@@ -453,7 +455,8 @@ class ASTMangler : public Mangler {
                   const ValueDecl *forDecl = nullptr);
   
   void appendDeclName(
-      const ValueDecl *decl, DeclBaseName name = DeclBaseName());
+      const ValueDecl *decl, DeclBaseName name = DeclBaseName(),
+      bool skipLocalDiscriminator = false);
 
   GenericTypeParamType *appendAssocType(DependentMemberType *DepTy,
                                         GenericSignature sig,
@@ -721,6 +724,7 @@ class ASTMangler : public Mangler {
 
   void appendInitializerEntity(const VarDecl *var);
   void appendBackingInitializerEntity(const VarDecl *var);
+  void appendPropertyWrappedFieldInitAccessorEntity(const VarDecl *var);
   void appendInitFromProjectedValueEntity(const VarDecl *var);
 
   CanType getDeclTypeForMangling(const ValueDecl *decl,
diff --git a/include/swift/AST/ASTNode.h b/include/swift/AST/ASTNode.h
index 5516762853b48..cf7470ddb1d02 100644
--- a/include/swift/AST/ASTNode.h
+++ b/include/swift/AST/ASTNode.h
@@ -21,6 +21,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "swift/Basic/Debug.h"
+#include "swift/Basic/SourceManager.h"
 #include "swift/AST/TypeAlignments.h"
 
 namespace llvm {
@@ -44,9 +45,15 @@ namespace swift {
   enum class PatternKind : uint8_t;
   enum class StmtKind;
 
-  struct ASTNode
-      : public llvm::PointerUnion<Expr *, Stmt *, Decl *, Pattern *, TypeRepr *,
-                                  StmtConditionElement *, CaseLabelItem *> {
+  namespace detail {
+  using ASTNodeBase =
+      llvm::PointerUnion<Expr *, Stmt *, Decl *, Pattern *, TypeRepr *,
+                         StmtConditionElement *, CaseLabelItem *>;
+  } // end namespace detail
+
+  struct ASTNode : public detail::ASTNodeBase {
+    using Base = detail::ASTNodeBase;
+
     // Inherit the constructors from PointerUnion.
     using PointerUnion::PointerUnion;
 
@@ -98,10 +105,24 @@ namespace swift {
       return llvm::hash_value(N.getOpaqueValue());
     }
   };
+
+  /// Find the outermost range that \p range was originally generated from.
+  /// Returns an invalid source range if \p range wasn't generated from a macro.
+  SourceRange getUnexpandedMacroRange(const SourceManager &SM,
+                                      SourceRange range);
+
 } // namespace swift
 
 namespace llvm {
   using swift::ASTNode;
+
+  /// `isa`, `dyn_cast`, `cast` for `ASTNode`.
+  template <typename To>
+  struct CastInfo<To, ASTNode> : public CastInfo<To, ASTNode::Base> {};
+  template <typename To>
+  struct CastInfo<To, const ASTNode>
+      : public CastInfo<To, const ASTNode::Base> {};
+
   template <> struct DenseMapInfo<ASTNode> {
     static inline ASTNode getEmptyKey() {
       return DenseMapInfo<swift::Expr *>::getEmptyKey();
diff --git a/include/swift/AST/ASTPrinter.h b/include/swift/AST/ASTPrinter.h
index 9a8accb07bf13..9d6459d46d124 100644
--- a/include/swift/AST/ASTPrinter.h
+++ b/include/swift/AST/ASTPrinter.h
@@ -413,7 +413,8 @@ class ExtraIndentStreamPrinter : public StreamPrinter {
 void printContext(raw_ostream &os, DeclContext *dc);
 
 bool printRequirementStub(ValueDecl *Requirement, DeclContext *Adopter,
-                          Type AdopterTy, SourceLoc TypeLoc, raw_ostream &OS);
+                          Type AdopterTy, SourceLoc TypeLoc, raw_ostream &OS,
+                          bool withExplicitObjCAttr = false);
 
 /// Print a keyword or punctuator directly by its kind.
 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, tok keyword);
@@ -441,7 +442,7 @@ StringRef getAccessorKindString(AccessorKind value);
 /// may be called multiple times if the declaration uses suppressible
 /// features.
 void printWithCompatibilityFeatureChecks(ASTPrinter &printer,
-                                         PrintOptions &options,
+                                         const PrintOptions &options,
                                          Decl *decl,
                                          llvm::function_ref<void()> printBody);
 
diff --git a/include/swift/AST/ASTScope.h b/include/swift/AST/ASTScope.h
index 9881ff2407d1a..746e40ea13164 100644
--- a/include/swift/AST/ASTScope.h
+++ b/include/swift/AST/ASTScope.h
@@ -75,7 +75,7 @@ class GenericParamList;
 class TrailingWhereClause;
 class ParameterList;
 class PatternBindingEntry;
-class SpecializeAttr;
+class AbstractSpecializeAttr;
 class GenericContext;
 class DeclName;
 class StmtConditionElement;
@@ -1241,10 +1241,10 @@ class TopLevelCodeScope final : public ASTScopeImpl {
 /// The \c _@specialize attribute.
 class SpecializeAttributeScope final : public ASTScopeImpl {
 public:
-  SpecializeAttr *const specializeAttr;
+  AbstractSpecializeAttr *const specializeAttr;
   AbstractFunctionDecl *const whatWasSpecialized;
 
-  SpecializeAttributeScope(SpecializeAttr *specializeAttr,
+  SpecializeAttributeScope(AbstractSpecializeAttr *specializeAttr,
                            AbstractFunctionDecl *whatWasSpecialized)
       : ASTScopeImpl(ScopeKind::SpecializeAttribute),
         specializeAttr(specializeAttr), whatWasSpecialized(whatWasSpecialized) {
diff --git a/include/swift/AST/ASTWalker.h b/include/swift/AST/ASTWalker.h
index e8f42599f1f15..f8fed39a1c6fc 100644
--- a/include/swift/AST/ASTWalker.h
+++ b/include/swift/AST/ASTWalker.h
@@ -603,6 +603,13 @@ class ASTWalker {
   /// params in AbstractFunctionDecl and NominalTypeDecl.
   virtual bool shouldWalkIntoGenericParams() { return false; }
 
+  /// Whether the walker should walk into any attached CustomAttrs.
+  virtual bool shouldWalkIntoCustomAttrs() const {
+    // Default to false currently since some walkers don't handle this case
+    // well.
+    return false;
+  }
+
   /// This method configures how the walker should walk the initializers of
   /// lazy variables. These initializers are semantically different from other
   /// initializers in their context and so sometimes should be visited as part
diff --git a/include/swift/AST/AccessorKind.h b/include/swift/AST/AccessorKind.h
new file mode 100644
index 0000000000000..930f8820a6c95
--- /dev/null
+++ b/include/swift/AST/AccessorKind.h
@@ -0,0 +1,37 @@
+//===-- AST/AccessorKind.h --------------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_AST_ACCESSOR_KIND_H
+#define SWIFT_AST_ACCESSOR_KIND_H
+
+/// `AccessorKind.h` is imported into Swift. Be *very* careful with what you
+/// include here and keep these includes minimal!
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
+#include "swift/Basic/SwiftBridging.h"
+
+namespace swift {
+
+// Note that the values of these enums line up with %select values in
+// diagnostics.
+enum class ENUM_EXTENSIBILITY_ATTR(closed) AccessorKind {
+#define ACCESSOR(ID, KEYWORD) ID SWIFT_NAME(#KEYWORD),
+#define INIT_ACCESSOR(ID, KEYWORD)                                             \
+  ID, // FIXME: We should be able to remove this once Linux CI host Swift is
+      // upgraded to 6.0
+#define LAST_ACCESSOR(ID) Last = ID
+#include "swift/AST/AccessorKinds.def"
+};
+
+} // namespace swift
+
+#endif // SWIFT_AST_ACCESSOR_KIND_H
diff --git a/include/swift/AST/AccessorKinds.def b/include/swift/AST/AccessorKinds.def
index bdba3d38a4b3d..0257b018456fe 100644
--- a/include/swift/AST/AccessorKinds.def
+++ b/include/swift/AST/AccessorKinds.def
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -20,22 +20,22 @@
 #error must define either ACCESSOR or ACCESSOR_KEYWORD
 #endif
 
-/// ACCESSOR(ID)
+/// ACCESSOR(ID, KEYWORD)
 ///   There is an accessor with the enumerator value AccessorKind::ID.
 #if !defined(ACCESSOR) && defined(ACCESSOR_KEYWORD)
-#define ACCESSOR(ID)
+#define ACCESSOR(ID, KEYWORD)
 #endif
 
 /// SINGLETON_ACCESSOR(ID, KEYWORD)
 ///   The given accessor has only one matching accessor keyword.
 ///
-/// Defaults to ACCESSOR(ID) or ACCESSOR_KEYWORD(KEYWORD), depending on which
-/// is defined.
+/// Defaults to ACCESSOR(ID, KEYWORD) or ACCESSOR_KEYWORD(KEYWORD), depending
+/// on which is defined.
 #ifndef SINGLETON_ACCESSOR
 #if defined(ACCESSOR_KEYWORD)
 #define SINGLETON_ACCESSOR(ID, KEYWORD) ACCESSOR_KEYWORD(KEYWORD)
 #else
-#define SINGLETON_ACCESSOR(ID, KEYWORD) ACCESSOR(ID)
+#define SINGLETON_ACCESSOR(ID, KEYWORD) ACCESSOR(ID, KEYWORD)
 #endif
 #endif
 
@@ -116,6 +116,14 @@
 #define INIT_ACCESSOR(ID, KEYWORD) SINGLETON_ACCESSOR(ID, KEYWORD)
 #endif
 
+#ifndef BORROW_ACCESSOR
+#define BORROW_ACCESSOR(ID, KEYWORD) SINGLETON_ACCESSOR(ID, KEYWORD)
+#endif
+
+#ifndef MUTATE_ACCESSOR
+#define MUTATE_ACCESSOR(ID, KEYWORD) SINGLETON_ACCESSOR(ID, KEYWORD)
+#endif
+
 /// This is a getter: a function that is called when a value is loaded
 /// from the storage.  It returns an owned value of the storage type.
 ///
@@ -217,8 +225,12 @@ MUTABLE_ADDRESSOR(MutableAddress, unsafeMutableAddress)
 /// re-writes assignment to initialization.
 INIT_ACCESSOR(Init, init)
 
+BORROW_ACCESSOR(Borrow, borrow)
+
+MUTATE_ACCESSOR(Mutate, mutate)
+
 #ifdef LAST_ACCESSOR
-LAST_ACCESSOR(Init)
+LAST_ACCESSOR(Mutate)
 #undef LAST_ACCESSOR
 #endif
 
diff --git a/include/swift/AST/ActorIsolation.h b/include/swift/AST/ActorIsolation.h
index 9d2f60388e90a..8bb4a06026259 100644
--- a/include/swift/AST/ActorIsolation.h
+++ b/include/swift/AST/ActorIsolation.h
@@ -28,6 +28,7 @@ class raw_ostream;
 
 namespace swift {
 class DeclContext;
+class Initializer;
 class ModuleDecl;
 class VarDecl;
 class NominalTypeDecl;
@@ -88,21 +89,75 @@ class ActorIsolation {
   /// Set to true if this was parsed from SIL.
   unsigned silParsed : 1;
 
-  unsigned parameterIndex : 27;
+  /// The opaque value of an EncodedParameterIndex.
+  /// Only meaningful for ActorInstance.
+  unsigned encodedParameterIndex : 27;
 
-  ActorIsolation(Kind kind, NominalTypeDecl *actor, unsigned parameterIndex);
+  class EncodedParameterIndex {
+    enum : unsigned {
+      SpecialIndex_Capture,
+      SpecialIndex_Self,
+      NumSpecialIndexes
+    };
+
+    /// Either a special index or (parameter index + NumSpecialIndexes).
+    unsigned value;
 
-  ActorIsolation(Kind kind, VarDecl *actor, unsigned parameterIndex);
+    constexpr EncodedParameterIndex(unsigned value) : value(value) {}
 
-  ActorIsolation(Kind kind, Expr *actor, unsigned parameterIndex);
+  public:
+    static constexpr EncodedParameterIndex parameter(unsigned index) {
+      return EncodedParameterIndex(NumSpecialIndexes + index);
+    }
+    static constexpr EncodedParameterIndex self() {
+      return EncodedParameterIndex(SpecialIndex_Self);
+    }
+    static constexpr EncodedParameterIndex capture() {
+      return EncodedParameterIndex(SpecialIndex_Capture);
+    }
+
+    unsigned getParameterIndex() const {
+      assert(value >= NumSpecialIndexes);
+      return value - NumSpecialIndexes;
+    }
+    bool isSelf() const {
+      return value == SpecialIndex_Self;
+    }
+    bool isCapture() const {
+      return value == SpecialIndex_Capture;
+    }
+
+    static EncodedParameterIndex fromOpaqueValue(unsigned value) {
+      return EncodedParameterIndex(value);
+    }
+    unsigned getOpaqueValue() const {
+      return value;
+    }
+  };
+
+  ActorIsolation(Kind kind, NominalTypeDecl *actor,
+                 EncodedParameterIndex parameterIndex);
+
+  ActorIsolation(Kind kind, VarDecl *actor,
+                 EncodedParameterIndex parameterIndex);
+
+  ActorIsolation(Kind kind, Expr *actor,
+                 EncodedParameterIndex parameterIndex);
 
   ActorIsolation(Kind kind, Type globalActor);
 
+  EncodedParameterIndex getEncodedParameterIndex() const {
+    return EncodedParameterIndex::fromOpaqueValue(encodedParameterIndex);
+  }
+
 public:
   // No-argument constructor needed for DenseMap use in PostfixCompletion.cpp
   explicit ActorIsolation(Kind kind = Unspecified, bool isSILParsed = false)
       : pointer(nullptr), kind(kind), isolatedByPreconcurrency(false),
-        silParsed(isSILParsed), parameterIndex(0) {}
+        silParsed(isSILParsed), encodedParameterIndex(0) {
+    // SIL's use of this has weaker invariants for now.
+    assert(kind != ActorInstance || isSILParsed);
+  }
 
   static ActorIsolation forUnspecified() {
     return ActorIsolation(Unspecified);
@@ -125,19 +180,22 @@ class ActorIsolation {
 
   static ActorIsolation forActorInstanceParameter(NominalTypeDecl *actor,
                                                   unsigned parameterIndex) {
-    return ActorIsolation(ActorInstance, actor, parameterIndex + 1);
+    return ActorIsolation(ActorInstance, actor,
+                          EncodedParameterIndex::parameter(parameterIndex));
   }
 
   static ActorIsolation forActorInstanceParameter(VarDecl *actor,
                                                   unsigned parameterIndex) {
-    return ActorIsolation(ActorInstance, actor, parameterIndex + 1);
+    return ActorIsolation(ActorInstance, actor,
+                          EncodedParameterIndex::parameter(parameterIndex));
   }
 
   static ActorIsolation forActorInstanceParameter(Expr *actor,
                                                   unsigned parameterIndex);
 
   static ActorIsolation forActorInstanceCapture(VarDecl *capturedActor) {
-    return ActorIsolation(ActorInstance, capturedActor, 0);
+    return ActorIsolation(ActorInstance, capturedActor,
+                          EncodedParameterIndex::capture());
   }
 
   static ActorIsolation forGlobalActor(Type globalActor) {
@@ -153,21 +211,14 @@ class ActorIsolation {
   static std::optional<ActorIsolation> forSILString(StringRef string) {
     auto kind =
         llvm::StringSwitch<std::optional<ActorIsolation::Kind>>(string)
-            .Case("unspecified",
-                  std::optional<ActorIsolation>(ActorIsolation::Unspecified))
-            .Case("actor_instance",
-                  std::optional<ActorIsolation>(ActorIsolation::ActorInstance))
-            .Case("nonisolated",
-                  std::optional<ActorIsolation>(ActorIsolation::Nonisolated))
-            .Case("nonisolated_unsafe", std::optional<ActorIsolation>(
-                                            ActorIsolation::NonisolatedUnsafe))
-            .Case("global_actor",
-                  std::optional<ActorIsolation>(ActorIsolation::GlobalActor))
-            .Case("global_actor_unsafe",
-                  std::optional<ActorIsolation>(ActorIsolation::GlobalActor))
+            .Case("unspecified", ActorIsolation::Unspecified)
+            .Case("actor_instance", ActorIsolation::ActorInstance)
+            .Case("nonisolated", ActorIsolation::Nonisolated)
+            .Case("nonisolated_unsafe", ActorIsolation::NonisolatedUnsafe)
+            .Case("global_actor", ActorIsolation::GlobalActor)
+            .Case("global_actor_unsafe", ActorIsolation::GlobalActor)
             .Case("caller_isolation_inheriting",
-                  std::optional<ActorIsolation>(
-                      ActorIsolation::CallerIsolationInheriting))
+                  ActorIsolation::CallerIsolationInheriting)
             .Default(std::nullopt);
     if (kind == std::nullopt)
       return std::nullopt;
@@ -187,17 +238,22 @@ class ActorIsolation {
   bool isNonisolatedUnsafe() const { return kind == NonisolatedUnsafe; }
 
   /// Retrieve the parameter to which actor-instance isolation applies.
-  ///
-  /// Parameter 0 is `self`.
-  unsigned getActorInstanceParameter() const {
+  unsigned getActorInstanceParameterIndex() const {
     assert(getKind() == ActorInstance);
-    return parameterIndex;
+    return getEncodedParameterIndex().getParameterIndex();
+  }
+
+  /// Given that this is actor instance isolation, is it a capture?
+  bool isActorInstanceForCapture() const {
+    assert(getKind() == ActorInstance);
+    return getEncodedParameterIndex().isCapture();
   }
 
   /// Returns true if this is an actor-instance isolation that additionally
   /// applies to the self parameter of a method.
   bool isActorInstanceForSelfParameter() const {
-    return getActorInstanceParameter() == 0;
+    assert(getKind() == ActorInstance);
+    return getEncodedParameterIndex().isSelf();
   }
 
   bool isSILParsed() const { return silParsed; }
@@ -217,6 +273,10 @@ class ActorIsolation {
     }
   }
 
+  /// In the debugger return the index for the stored actorInstance pointer
+  /// union index. Asserts if not an actor instance.
+  SWIFT_DEBUG_HELPER(unsigned getActorInstanceUnionIndex() const);
+
   NominalTypeDecl *getActor() const;
 
   VarDecl *getActorInstance() const;
@@ -281,13 +341,13 @@ class ActorIsolation {
     id.AddPointer(pointer);
     id.AddBoolean(isolatedByPreconcurrency);
     id.AddBoolean(silParsed);
-    id.AddInteger(parameterIndex);
+    id.AddInteger(encodedParameterIndex);
   }
 
   friend llvm::hash_code hash_value(const ActorIsolation &state) {
     return llvm::hash_combine(state.kind, state.pointer,
                               state.isolatedByPreconcurrency, state.silParsed,
-                              state.parameterIndex);
+                              state.encodedParameterIndex);
   }
 
   void print(llvm::raw_ostream &os) const;
@@ -375,6 +435,10 @@ InferredActorIsolation getInferredActorIsolation(ValueDecl *value);
 ActorIsolation
 __AbstractClosureExpr_getActorIsolation(AbstractClosureExpr *CE);
 
+/// Determine how the given initialization context is isolated.
+ActorIsolation getActorIsolation(Initializer *init,
+                                 bool ignoreDefaultArguments = false);
+
 /// Determine how the given declaration context is isolated.
 /// \p getClosureActorIsolation allows the specification of actor isolation for
 /// closures that haven't been saved been saved to the AST yet. This is useful
diff --git a/include/swift/AST/AnyFunctionRef.h b/include/swift/AST/AnyFunctionRef.h
index 3f5e0cb309983..bdfca59bbb755 100644
--- a/include/swift/AST/AnyFunctionRef.h
+++ b/include/swift/AST/AnyFunctionRef.h
@@ -72,13 +72,13 @@ class AnyFunctionRef {
   CaptureInfo getCaptureInfo() const {
     if (auto *AFD = TheFunction.dyn_cast<AbstractFunctionDecl *>())
       return AFD->getCaptureInfo();
-    return TheFunction.get<AbstractClosureExpr *>()->getCaptureInfo();
+    return cast<AbstractClosureExpr *>(TheFunction)->getCaptureInfo();
   }
 
   ParameterList *getParameters() const {
     if (auto *AFD = TheFunction.dyn_cast<AbstractFunctionDecl *>())
       return AFD->getParameters();
-    return TheFunction.get<AbstractClosureExpr *>()->getParameters();
+    return cast<AbstractClosureExpr *>(TheFunction)->getParameters();
   }
 
   bool hasExternalPropertyWrapperParameters() const {
@@ -90,7 +90,7 @@ class AnyFunctionRef {
   Type getType() const {
     if (auto *AFD = TheFunction.dyn_cast<AbstractFunctionDecl *>())
       return AFD->getInterfaceType();
-    return TheFunction.get<AbstractClosureExpr *>()->getType();
+    return cast<AbstractClosureExpr *>(TheFunction)->getType();
   }
 
   Type getBodyResultType() const {
@@ -99,7 +99,7 @@ class AnyFunctionRef {
         return FD->mapTypeIntoContext(FD->getResultInterfaceType());
       return TupleType::getEmpty(AFD->getASTContext());
     }
-    return TheFunction.get<AbstractClosureExpr *>()->getResultType();
+    return cast<AbstractClosureExpr *>(TheFunction)->getResultType();
   }
 
   ArrayRef<AnyFunctionType::Yield>
@@ -115,7 +115,7 @@ class AnyFunctionRef {
   BraceStmt *getBody() const {
     if (auto *AFD = TheFunction.dyn_cast<AbstractFunctionDecl *>())
       return AFD->getBody();
-    auto *ACE = TheFunction.get<AbstractClosureExpr *>();
+    auto *ACE = cast<AbstractClosureExpr *>(TheFunction);
     if (auto *CE = dyn_cast<ClosureExpr>(ACE))
       return CE->getBody();
     return cast<AutoClosureExpr>(ACE)->getBody();
@@ -127,7 +127,7 @@ class AnyFunctionRef {
       return;
     }
 
-    auto *ACE = TheFunction.get<AbstractClosureExpr *>();
+    auto *ACE = cast<AbstractClosureExpr *>(TheFunction);
     if (auto *CE = dyn_cast<ClosureExpr>(ACE)) {
       CE->setBody(stmt);
       CE->setBodyState(ClosureExpr::BodyState::Parsed);
@@ -143,7 +143,7 @@ class AnyFunctionRef {
       return;
     }
 
-    auto *ACE = TheFunction.get<AbstractClosureExpr *>();
+    auto *ACE = cast<AbstractClosureExpr *>(TheFunction);
     if (auto *CE = dyn_cast<ClosureExpr>(ACE)) {
       CE->setBody(stmt);
       CE->setBodyState(ClosureExpr::BodyState::TypeChecked);
@@ -168,7 +168,7 @@ class AnyFunctionRef {
   DeclContext *getAsDeclContext() const {
     if (auto *AFD = TheFunction.dyn_cast<AbstractFunctionDecl *>())
       return AFD;
-    return TheFunction.get<AbstractClosureExpr *>();
+    return cast<AbstractClosureExpr *>(TheFunction);
   }
   
   AbstractFunctionDecl *getAbstractFunctionDecl() const {
@@ -179,6 +179,14 @@ class AnyFunctionRef {
     return TheFunction.dyn_cast<AbstractClosureExpr*>();
   }
 
+  AccessorDecl *getAccessorDecl() const {
+    if (auto *accessor = dyn_cast_or_null<AccessorDecl>(
+            TheFunction.dyn_cast<AbstractFunctionDecl *>())) {
+      return accessor;
+    }
+    return nullptr;
+  }
+
   /// Whether this function is @Sendable.
   bool isSendable() const {
     if (auto *fnType = getType()->getAs<AnyFunctionType>())
diff --git a/include/swift/AST/Attr.h b/include/swift/AST/Attr.h
index 9f6d49eb6bf36..5bf4de457bab6 100644
--- a/include/swift/AST/Attr.h
+++ b/include/swift/AST/Attr.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -16,7 +16,6 @@
 
 #ifndef SWIFT_ATTR_H
 #define SWIFT_ATTR_H
-
 #include "swift/AST/ASTAllocated.h"
 #include "swift/AST/AttrKind.h"
 #include "swift/AST/AutoDiff.h"
@@ -29,7 +28,7 @@
 #include "swift/AST/LifetimeDependence.h"
 #include "swift/AST/MacroDeclaration.h"
 #include "swift/AST/Ownership.h"
-#include "swift/AST/PlatformKind.h"
+#include "swift/AST/PlatformKindUtils.h"
 #include "swift/AST/StorageImpl.h"
 #include "swift/Basic/Debug.h"
 #include "swift/Basic/EnumTraits.h"
@@ -42,10 +41,10 @@
 #include "swift/Basic/SourceLoc.h"
 #include "swift/Basic/UUID.h"
 #include "swift/Basic/Version.h"
-#include "llvm/ADT/bit.h"
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/bit.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/TrailingObjects.h"
@@ -107,7 +106,46 @@ class alignas(1 << AttrAlignInBits) AttributeBase
 class DeclAttributes;
 enum class DeclKind : uint8_t;
 
-  /// Represents one declaration attribute.
+enum : unsigned {
+  NumInlineKindBits =
+      countBitsUsed(static_cast<unsigned>(InlineKind::Last_InlineKind))
+};
+
+enum : unsigned {
+  NumEffectsKindBits =
+      countBitsUsed(static_cast<unsigned>(EffectsKind::Last_EffectsKind))
+};
+
+enum : unsigned {
+  NumExposureKindBits =
+      countBitsUsed(static_cast<unsigned>(ExposureKind::Last_ExposureKind))
+};
+
+enum : unsigned {
+  NumExternKindBits =
+      countBitsUsed(static_cast<unsigned>(ExternKind::Last_ExternKind))
+};
+
+enum : unsigned {
+  NumNonIsolatedModifierBits = countBitsUsed(
+      static_cast<unsigned>(NonIsolatedModifier::Last_NonIsolatedModifier))
+};
+
+enum : unsigned {
+  NumInheritActorContextKindBits = countBitsUsed(static_cast<unsigned>(
+      InheritActorContextModifier::Last_InheritActorContextKind))
+};
+
+enum : unsigned {
+  NumNonexhaustiveModeBits = countBitsUsed(
+      static_cast<unsigned>(NonexhaustiveMode::Last_NonexhaustiveMode))
+};
+
+enum : unsigned { NumDeclAttrKindBits = countBitsUsed(NumDeclAttrKinds - 1) };
+
+enum : unsigned { NumTypeAttrKindBits = countBitsUsed(NumTypeAttrKinds - 1) };
+
+/// Represents one declaration attribute.
 class DeclAttribute : public AttributeBase {
   friend class DeclAttributes;
 
@@ -203,7 +241,7 @@ class DeclAttribute : public AttributeBase {
       ownership : NumReferenceOwnershipBits
     );
 
-    SWIFT_INLINE_BITFIELD(SpecializeAttr, DeclAttribute, 1+1,
+    SWIFT_INLINE_BITFIELD(AbstractSpecializeAttr, DeclAttribute, 1+1,
       exported : 1,
       kind : 1
     );
@@ -226,8 +264,12 @@ class DeclAttribute : public AttributeBase {
       isEarlyAdopter : 1
     );
 
-    SWIFT_INLINE_BITFIELD(NonisolatedAttr, DeclAttribute, 1,
-      isUnsafe : 1
+    SWIFT_INLINE_BITFIELD(NonisolatedAttr, DeclAttribute, NumNonIsolatedModifierBits,
+      Modifier : NumNonIsolatedModifierBits
+    );
+
+    SWIFT_INLINE_BITFIELD(InheritActorContextAttr, DeclAttribute, NumInheritActorContextKindBits,
+      Modifier : NumInheritActorContextKindBits
     );
 
     SWIFT_INLINE_BITFIELD_FULL(AllowFeatureSuppressionAttr, DeclAttribute, 1+31,
@@ -237,8 +279,12 @@ class DeclAttribute : public AttributeBase {
       NumFeatures : 31
     );
 
-    SWIFT_INLINE_BITFIELD(ExecutionAttr, DeclAttribute, NumExecutionKindBits,
-      Behavior : NumExecutionKindBits
+    SWIFT_INLINE_BITFIELD(LifetimeAttr, DeclAttribute, 1,
+      isUnderscored : 1
+    );
+
+    SWIFT_INLINE_BITFIELD(NonexhaustiveAttr, DeclAttribute, NumNonexhaustiveModeBits,
+      mode : NumNonexhaustiveModeBits
     );
   } Bits;
   // clang-format on
@@ -384,21 +430,14 @@ class DeclAttribute : public AttributeBase {
     /// valid if they match. 
     EquivalentInABIAttr = 1ull << 18,
 
-    /// Attribute can be used in an \c \@abi attribute, but must match
-    /// equivalent on API decl; if omitted, API decl's attribute will be 
-    /// cloned. Use where you would want to use \c EquivalentInABIAttr but 
-    /// repeating the attribute is judged too burdensome.
-    InferredInABIAttr = 1ull << 19,
-
     /// Use for attributes which are \em only valid on declarations that cannot
     /// have an \c @abi attribute, such as \c ImportDecl .
-    UnreachableInABIAttr = 1ull << 20,
+    UnreachableInABIAttr = 1ull << 19,
   };
 
   enum : uint64_t {
     InABIAttrMask = ForbiddenInABIAttr | UnconstrainedInABIAttr
-                  | EquivalentInABIAttr | InferredInABIAttr
-                  | UnreachableInABIAttr
+                  | EquivalentInABIAttr | UnreachableInABIAttr
   };
 
   LLVM_READNONE
@@ -694,22 +733,29 @@ class SectionAttr : public DeclAttribute {
 /// Defines the @_cdecl attribute.
 class CDeclAttr : public DeclAttribute {
 public:
-  CDeclAttr(StringRef Name, SourceLoc AtLoc, SourceRange Range, bool Implicit)
-      : DeclAttribute(DeclAttrKind::CDecl, AtLoc, Range, Implicit), Name(Name) {
+  CDeclAttr(StringRef Name, SourceLoc AtLoc, SourceRange Range, bool Implicit,
+            bool Underscored)
+      : DeclAttribute(DeclAttrKind::CDecl, AtLoc, Range, Implicit),
+        Name(Name), Underscored(Underscored) {
   }
 
-  CDeclAttr(StringRef Name, bool Implicit)
-    : CDeclAttr(Name, SourceLoc(), SourceRange(), Implicit) {}
+  CDeclAttr(StringRef Name, bool Implicit, bool Underscored)
+    : CDeclAttr(Name, SourceLoc(), SourceRange(), Implicit, Underscored) {}
 
   /// The symbol name.
   const StringRef Name;
 
+  /// Is this the version of the attribute that's underscored?
+  /// Used to preserve retro compatibility with early adopters.
+  const bool Underscored;
+
   static bool classof(const DeclAttribute *DA) {
     return DA->getKind() == DeclAttrKind::CDecl;
   }
 
   CDeclAttr *clone(ASTContext &ctx) const {
-    return new (ctx) CDeclAttr(Name, AtLoc, Range, isImplicit());
+    return new (ctx) CDeclAttr(Name, AtLoc, Range, isImplicit(),
+                               Underscored);
   }
 
   bool isEquivalent(const CDeclAttr *other, Decl *attachedTo) const {
@@ -1052,7 +1098,7 @@ class ObjCAttr final : public DeclAttribute,
     unsigned length = 2;
     if (auto name = getName())
       length += name->getNumSelectorPieces();
-    return {getTrailingObjects<SourceLoc>(), length};
+    return getTrailingObjects(length);
   }
 
   /// Retrieve the trailing location information.
@@ -1061,7 +1107,7 @@ class ObjCAttr final : public DeclAttribute,
     unsigned length = 2;
     if (auto name = getName())
       length += name->getNumSelectorPieces();
-    return {getTrailingObjects<SourceLoc>(), length};
+    return getTrailingObjects(length);
   }
 
 public:
@@ -1237,14 +1283,14 @@ class DynamicReplacementAttr final
   MutableArrayRef<SourceLoc> getTrailingLocations() {
     assert(Bits.DynamicReplacementAttr.HasTrailingLocationInfo);
     unsigned length = 2;
-    return {getTrailingObjects<SourceLoc>(), length};
+    return getTrailingObjects(length);
   }
 
   /// Retrieve the trailing location information.
   ArrayRef<SourceLoc> getTrailingLocations() const {
     assert(Bits.DynamicReplacementAttr.HasTrailingLocationInfo);
     unsigned length = 2; // lParens, rParens
-    return {getTrailingObjects<SourceLoc>(), length};
+    return getTrailingObjects(length);
   }
 
 public:
@@ -1434,8 +1480,7 @@ class SPIAccessControlAttr final : public DeclAttribute,
   /// Note: A single SPI name per attribute is currently supported but this
   /// may change with the syntax change.
   ArrayRef<Identifier> getSPIGroups() const {
-    return { this->template getTrailingObjects<Identifier>(),
-             numSPIGroups };
+    return getTrailingObjects(numSPIGroups);
   }
 
   static bool classof(const DeclAttribute *DA) {
@@ -1730,15 +1775,17 @@ class SynthesizedProtocolAttr : public DeclAttribute {
   }
 };
 
-/// The @_specialize attribute, which forces specialization on the specified
-/// type list.
-class SpecializeAttr final
+/// The @_specialize/@specialize attribute, which forces specialization on the
+/// specified type list.
+template<typename Base, typename...AdditionalTrailingObjects>
+using SpecializeAttrTrailingObjects = llvm::TrailingObjects<Base,
+  Identifier, AvailableAttr *, Type , AdditionalTrailingObjects...>;
+
+class AbstractSpecializeAttr
     : public DeclAttribute,
-      private llvm::TrailingObjects<SpecializeAttr, Identifier,
-                                    AvailableAttr *, Type> {
+      private llvm::trailing_objects_internal::TrailingObjectsBase {
   friend class SpecializeAttrTargetDeclRequest;
   friend class SerializeAttrGenericSignatureRequest;
-  friend TrailingObjects;
 
 public:
   // NOTE: When adding new kinds, you must update the inline bitfield macro.
@@ -1759,37 +1806,16 @@ class SpecializeAttr final
   size_t numTypeErasedParams;
   bool typeErasedParamsInitialized;
 
-  SpecializeAttr(SourceLoc atLoc, SourceRange Range,
-                 TrailingWhereClause *clause, bool exported,
+protected:
+  AbstractSpecializeAttr(DeclAttrKind DK, SourceLoc atLoc, SourceRange Range,
+                 TrailingWhereClause *clause,
+                 bool exported,
                  SpecializationKind kind, GenericSignature specializedSignature,
                  DeclNameRef targetFunctionName, ArrayRef<Identifier> spiGroups,
                  ArrayRef<AvailableAttr *> availabilityAttrs,
                  size_t typeErasedParamsCount);
 
 public:
-  static SpecializeAttr *
-  create(ASTContext &Ctx, SourceLoc atLoc, SourceRange Range,
-         TrailingWhereClause *clause, bool exported, SpecializationKind kind,
-         DeclNameRef targetFunctionName, ArrayRef<Identifier> spiGroups,
-         ArrayRef<AvailableAttr *> availabilityAttrs,
-         GenericSignature specializedSignature = nullptr);
-
-  static SpecializeAttr *create(ASTContext &ctx, bool exported,
-                                SpecializationKind kind,
-                                ArrayRef<Identifier> spiGroups,
-                                ArrayRef<AvailableAttr *> availabilityAttrs,
-                                GenericSignature specializedSignature,
-                                DeclNameRef replacedFunction);
-
-  static SpecializeAttr *create(ASTContext &ctx, bool exported,
-                                SpecializationKind kind,
-                                ArrayRef<Identifier> spiGroups,
-                                ArrayRef<AvailableAttr *> availabilityAttrs,
-                                ArrayRef<Type> typeErasedParams,
-                                GenericSignature specializedSignature,
-                                DeclNameRef replacedFunction,
-                                LazyMemberLoader *resolver, uint64_t data);
-
   size_t numTrailingObjects(OverloadToken<Identifier>) const {
     return numSPIGroups;
   }
@@ -1797,17 +1823,27 @@ class SpecializeAttr final
   size_t numTrailingObjects(OverloadToken<AvailableAttr *>) const {
     return numAvailableAttrs;
   }
+  // Helper to get the trailing objects of one of the subclasses.
+  template<typename Type>
+  const Type *getSubclassTrailingObjects() const;
+
+  template<typename Type>
+  Type *getSubclassTrailingObjects() {
+    const auto *constThis = this;
+    return const_cast<Type*>(constThis->getSubclassTrailingObjects<Type>());
+  }
+
   /// Name of SPIs declared by the attribute.
   ///
   /// Note: A single SPI name per attribute is currently supported but this
   /// may change with the syntax change.
   ArrayRef<Identifier> getSPIGroups() const {
-    return { this->template getTrailingObjects<Identifier>(),
+    return { getSubclassTrailingObjects<Identifier>(),
              numSPIGroups };
   }
 
   ArrayRef<AvailableAttr *> getAvailableAttrs() const {
-    return {this->template getTrailingObjects<AvailableAttr *>(),
+    return {getSubclassTrailingObjects<AvailableAttr *>(),
             numAvailableAttrs};
   }
 
@@ -1815,26 +1851,36 @@ class SpecializeAttr final
     if (!typeErasedParamsInitialized)
       return {};
 
-    return {this->template getTrailingObjects<Type>(),
+    return {getSubclassTrailingObjects<Type>(),
             numTypeErasedParams};
   }
 
   void setTypeErasedParams(const ArrayRef<Type> typeErasedParams) {
     assert(typeErasedParams.size() == numTypeErasedParams);
     if (!typeErasedParamsInitialized) {
-      std::uninitialized_copy(typeErasedParams.begin(), typeErasedParams.end(), getTrailingObjects<Type>());
+      std::uninitialized_copy(typeErasedParams.begin(), typeErasedParams.end(),
+                              getSubclassTrailingObjects<Type>());
       typeErasedParamsInitialized = true;
     }
   }
 
+  void setResolver(LazyMemberLoader *resolver, uint64_t resolverContextData) {
+    this->resolver = resolver;
+    this->resolverContextData = resolverContextData;
+  }
+
   TrailingWhereClause *getTrailingWhereClause() const;
 
+  bool isPublic() const {
+    return getKind() == DeclAttrKind::Specialized;
+  }
+
   bool isExported() const {
-    return Bits.SpecializeAttr.exported;
+    return Bits.AbstractSpecializeAttr.exported;
   }
 
   SpecializationKind getSpecializationKind() const {
-    return SpecializationKind(Bits.SpecializeAttr.kind);
+    return SpecializationKind(Bits.AbstractSpecializeAttr.kind);
   }
 
   bool isFullSpecialization() const {
@@ -1856,15 +1902,140 @@ class SpecializeAttr final
   GenericSignature
   getSpecializedSignature(const AbstractFunctionDecl *forDecl) const;
 
+  static bool classof(const DeclAttribute *DA) {
+    return DA->getKind() == DeclAttrKind::Specialize ||
+      DA->getKind() == DeclAttrKind::Specialized;
+  }
+
+  UNIMPLEMENTED_CLONE(AbstractSpecializeAttr)
+
+  bool isEquivalent(const AbstractSpecializeAttr *other, Decl *attachedTo) const;
+};
+
+/// The @_specialize attribute.
+class SpecializeAttr final : public AbstractSpecializeAttr,
+   private SpecializeAttrTrailingObjects<SpecializeAttr> {
+  friend TrailingObjects;
+  friend AbstractSpecializeAttr;
+
+  // WARNING: Do not add storage here. The base class uses TrailingObjects.
+private:
+  SpecializeAttr(SourceLoc atLoc, SourceRange Range,
+                 TrailingWhereClause *clause,
+                 bool exported,
+                 SpecializationKind kind, GenericSignature specializedSignature,
+                 DeclNameRef targetFunctionName, ArrayRef<Identifier> spiGroups,
+                 ArrayRef<AvailableAttr *> availabilityAttrs,
+                 size_t typeErasedParamsCount) :
+    AbstractSpecializeAttr(DeclAttrKind::Specialize, atLoc, Range, clause,
+                   exported, kind, specializedSignature, targetFunctionName,
+                   spiGroups, availabilityAttrs, typeErasedParamsCount) {}
+
+public:
+  static SpecializeAttr *
+  create(ASTContext &Ctx, SourceLoc atLoc, SourceRange Range,
+         TrailingWhereClause *clause, bool exported,
+         SpecializationKind kind,
+         DeclNameRef targetFunctionName, ArrayRef<Identifier> spiGroups,
+         ArrayRef<AvailableAttr *> availabilityAttrs,
+         GenericSignature specializedSignature = nullptr);
+
+  static SpecializeAttr *create(ASTContext &ctx, bool exported,
+                                SpecializationKind kind,
+                                ArrayRef<Identifier> spiGroups,
+                                ArrayRef<AvailableAttr *> availabilityAttrs,
+                                GenericSignature specializedSignature,
+                                DeclNameRef replacedFunction);
+
+  static SpecializeAttr *create(ASTContext &ctx, bool exported,
+                                SpecializationKind kind,
+                                ArrayRef<Identifier> spiGroups,
+                                ArrayRef<AvailableAttr *> availabilityAttrs,
+                                ArrayRef<Type> typeErasedParams,
+                                GenericSignature specializedSignature,
+                                DeclNameRef replacedFunction,
+                                LazyMemberLoader *resolver, uint64_t data);
+
   static bool classof(const DeclAttribute *DA) {
     return DA->getKind() == DeclAttrKind::Specialize;
   }
 
   UNIMPLEMENTED_CLONE(SpecializeAttr)
 
-  bool isEquivalent(const SpecializeAttr *other, Decl *attachedTo) const;
+  bool isEquivalent(const SpecializeAttr *other, Decl *attachedTo) const {
+    return AbstractSpecializeAttr::isEquivalent(other, attachedTo);
+  }
 };
 
+/// The @specialized attribute.
+class SpecializedAttr final : public AbstractSpecializeAttr ,
+   private SpecializeAttrTrailingObjects<SpecializeAttr> {
+  friend TrailingObjects;
+  friend AbstractSpecializeAttr;
+
+  // WARNING: Do not add storage here. The base class uses TrailingObjects.
+private:
+
+  SpecializedAttr(SourceLoc atLoc, SourceRange Range,
+                 TrailingWhereClause *clause,
+                 bool exported,
+                 SpecializationKind kind, GenericSignature specializedSignature,
+                 DeclNameRef targetFunctionName, ArrayRef<Identifier> spiGroups,
+                 ArrayRef<AvailableAttr *> availabilityAttrs,
+                 size_t typeErasedParamsCount) :
+    AbstractSpecializeAttr(DeclAttrKind::Specialized, atLoc, Range, clause,
+                   exported, kind, specializedSignature, targetFunctionName,
+                   spiGroups, availabilityAttrs, typeErasedParamsCount) {}
+
+public:
+  static SpecializedAttr *
+  create(ASTContext &Ctx, SourceLoc atLoc, SourceRange Range,
+         TrailingWhereClause *clause, bool exported,
+         SpecializationKind kind,
+         DeclNameRef targetFunctionName, ArrayRef<Identifier> spiGroups,
+         ArrayRef<AvailableAttr *> availabilityAttrs,
+         GenericSignature specializedSignature = nullptr);
+
+  static SpecializedAttr *create(ASTContext &ctx, bool exported,
+                                SpecializationKind kind,
+                                ArrayRef<Identifier> spiGroups,
+                                ArrayRef<AvailableAttr *> availabilityAttrs,
+                                GenericSignature specializedSignature,
+                                DeclNameRef replacedFunction);
+
+  static SpecializedAttr *create(ASTContext &ctx, bool exported,
+                                SpecializationKind kind,
+                                ArrayRef<Identifier> spiGroups,
+                                ArrayRef<AvailableAttr *> availabilityAttrs,
+                                ArrayRef<Type> typeErasedParams,
+                                GenericSignature specializedSignature,
+                                DeclNameRef replacedFunction,
+                                LazyMemberLoader *resolver, uint64_t data);
+
+  static bool classof(const DeclAttribute *DA) {
+    return DA->getKind() == DeclAttrKind::Specialized;
+  }
+
+  UNIMPLEMENTED_CLONE(SpecializedAttr)
+
+  bool isEquivalent(const SpecializedAttr *other, Decl *attachedTo) const {
+    return AbstractSpecializeAttr::isEquivalent(other, attachedTo);
+  }
+};
+
+template<typename Type>
+const Type *AbstractSpecializeAttr::getSubclassTrailingObjects() const {
+  if (auto attr = dyn_cast<SpecializedAttr>(this)) {
+    return attr->getTrailingObjects<Type>();
+  }
+  if (auto attr = dyn_cast<SpecializeAttr>(this)) {
+    return attr->getTrailingObjects<Type>();
+  }
+  llvm_unreachable("unhandled AbstractSpecializeAttr subclass?");
+}
+
+
+
 class StorageRestrictionsAttr final
     : public DeclAttribute,
       private llvm::TrailingObjects<StorageRestrictionsAttr, Identifier> {
@@ -1887,11 +2058,11 @@ class StorageRestrictionsAttr final
   unsigned getNumAccessesProperties() const { return NumAccesses; }
 
   ArrayRef<Identifier> getInitializesNames() const {
-    return {getTrailingObjects<Identifier>(), NumInitializes};
+    return getTrailingObjects(NumInitializes);
   }
 
   ArrayRef<Identifier> getAccessesNames() const {
-    return {getTrailingObjects<Identifier>() + NumInitializes, NumAccesses};
+    return {getTrailingObjects() + NumInitializes, NumAccesses};
   }
 
   ArrayRef<VarDecl *> getInitializesProperties(AccessorDecl *attachedTo) const;
@@ -2172,6 +2343,8 @@ class CustomAttr final : public DeclAttribute {
 
   bool isEquivalent(const CustomAttr *other, Decl *attachedTo) const;
 
+  void printCustomAttr(ASTPrinter &Printer, const PrintOptions &Options) const;
+
 private:
   friend class CustomAttrNominalRequest;
   void resetTypeInformation(TypeExpr *repr);
@@ -2227,6 +2400,11 @@ class ProjectedValuePropertyAttr : public DeclAttribute {
 /// The variable \p foo was originally defined in another module called
 /// \p Original prior to OSX 10.15
 class OriginallyDefinedInAttr: public DeclAttribute {
+  const StringRef ManglingModuleName;
+  const StringRef LinkerModuleName;
+  const PlatformKind Platform;
+  const llvm::VersionTuple MovedVersion;
+
 public:
   OriginallyDefinedInAttr(SourceLoc AtLoc, SourceRange Range,
                           StringRef OriginalModuleName,
@@ -2248,16 +2426,22 @@ class OriginallyDefinedInAttr: public DeclAttribute {
   OriginallyDefinedInAttr *clone(ASTContext &C, bool implicit) const;
 
   // The original module name for mangling.
-  const StringRef ManglingModuleName;
+  StringRef getManglingModuleName() const { return ManglingModuleName; }
 
   // The original module name for linker directives.
-  const StringRef LinkerModuleName;
+  StringRef getLinkerModuleName() const { return LinkerModuleName; }
 
   /// The platform of the symbol.
-  const PlatformKind Platform;
+  PlatformKind getPlatform() const { return Platform; }
 
-  /// Indicates when the symbol was moved here.
-  const llvm::VersionTuple MovedVersion;
+  /// The version of the platform that the symbol was moved in, as it was
+  /// written in source.
+  llvm::VersionTuple getParsedMovedVersion() const { return MovedVersion; }
+
+  /// The version of the platform that the symbol was moved in. This may be
+  /// different than the version that was written in source due to
+  /// canonicalization.
+  llvm::VersionTuple getMovedVersion() const;
 
   struct ActiveVersion {
     StringRef ManglingModuleName;
@@ -2377,10 +2561,10 @@ class DifferentiableAttr final
   /// The parsed differentiability parameters, i.e. the list of parameters
   /// specified in 'wrt:'.
   ArrayRef<ParsedAutoDiffParameter> getParsedParameters() const {
-    return {getTrailingObjects<ParsedAutoDiffParameter>(), NumParsedParameters};
+    return getTrailingObjects(NumParsedParameters);
   }
   MutableArrayRef<ParsedAutoDiffParameter> getParsedParameters() {
-    return {getTrailingObjects<ParsedAutoDiffParameter>(), NumParsedParameters};
+    return getTrailingObjects(NumParsedParameters);
   }
   size_t numTrailingObjects(OverloadToken<ParsedAutoDiffParameter>) const {
     return NumParsedParameters;
@@ -2562,10 +2746,10 @@ class DerivativeAttr final
   /// The parsed differentiability parameters, i.e. the list of parameters
   /// specified in 'wrt:'.
   ArrayRef<ParsedAutoDiffParameter> getParsedParameters() const {
-    return {getTrailingObjects<ParsedAutoDiffParameter>(), NumParsedParameters};
+    return getTrailingObjects(NumParsedParameters);
   }
   MutableArrayRef<ParsedAutoDiffParameter> getParsedParameters() {
-    return {getTrailingObjects<ParsedAutoDiffParameter>(), NumParsedParameters};
+    return getTrailingObjects(NumParsedParameters);
   }
   size_t numTrailingObjects(OverloadToken<ParsedAutoDiffParameter>) const {
     return NumParsedParameters;
@@ -2653,10 +2837,10 @@ class TransposeAttr final
   /// The parsed linearity parameters, i.e. the list of parameters specified in
   /// 'wrt:'.
   ArrayRef<ParsedAutoDiffParameter> getParsedParameters() const {
-    return {getTrailingObjects<ParsedAutoDiffParameter>(), NumParsedParameters};
+    return getTrailingObjects(NumParsedParameters);
   }
   MutableArrayRef<ParsedAutoDiffParameter> getParsedParameters() {
-    return {getTrailingObjects<ParsedAutoDiffParameter>(), NumParsedParameters};
+    return getTrailingObjects(NumParsedParameters);
   }
   size_t numTrailingObjects(OverloadToken<ParsedAutoDiffParameter>) const {
     return NumParsedParameters;
@@ -2756,21 +2940,35 @@ class UnavailableFromAsyncAttr : public DeclAttribute {
 /// available for back deployment to older OSes via emission into the client
 /// binary.
 class BackDeployedAttr : public DeclAttribute {
+  const PlatformKind Platform;
+  const llvm::VersionTuple Version;
+
 public:
   BackDeployedAttr(SourceLoc AtLoc, SourceRange Range, PlatformKind Platform,
                    const llvm::VersionTuple &Version, bool Implicit)
       : DeclAttribute(DeclAttrKind::BackDeployed, AtLoc, Range, Implicit),
         Platform(Platform), Version(Version) {}
 
-  /// The platform the symbol is available for back deployment on.
-  const PlatformKind Platform;
+  /// The platform the decl is available for back deployment in.
+  PlatformKind getPlatform() const { return Platform; }
 
-  /// The earliest platform version that may use the back deployed implementation.
-  const llvm::VersionTuple Version;
+  /// The `before:` version tuple that was written in source.
+  llvm::VersionTuple getParsedVersion() const { return Version; }
+
+  /// The `before:` version, which is the earliest platform version that may use
+  /// the back deployed implementation. This may be different from the version
+  /// that was written in source due to canonicalization.
+  llvm::VersionTuple getVersion() const;
 
   /// Returns true if this attribute is active given the current platform.
   bool isActivePlatform(const ASTContext &ctx, bool forTargetVariant) const;
 
+  /// Returns the `AvailabilityDomain` that the decl is available for back
+  /// deployment in.
+  AvailabilityDomain getAvailabilityDomain() const {
+    return AvailabilityDomain::forPlatform(Platform);
+  }
+
   static bool classof(const DeclAttribute *DA) {
     return DA->getKind() == DeclAttrKind::BackDeployed;
   }
@@ -2978,17 +3176,28 @@ class ObjCImplementationAttr final : public DeclAttribute {
 /// Represents nonisolated modifier.
 class NonisolatedAttr final : public DeclAttribute {
 public:
-  NonisolatedAttr(SourceLoc atLoc, SourceRange range, bool unsafe,
-                  bool implicit)
+  NonisolatedAttr(SourceLoc atLoc, SourceRange range,
+                  NonIsolatedModifier modifier, bool implicit)
       : DeclAttribute(DeclAttrKind::Nonisolated, atLoc, range, implicit) {
-    Bits.NonisolatedAttr.isUnsafe = unsafe;
-    assert((isUnsafe() == unsafe) && "not enough bits for unsafe state");
+    Bits.NonisolatedAttr.Modifier = static_cast<unsigned>(modifier);
+    assert((getModifier() == modifier) && "not enough bits for modifier");
+  }
+
+  NonIsolatedModifier getModifier() const {
+    return static_cast<NonIsolatedModifier>(Bits.NonisolatedAttr.Modifier);
   }
 
-  NonisolatedAttr(bool unsafe, bool implicit)
-      : NonisolatedAttr({}, {}, unsafe, implicit) {}
+  bool isUnsafe() const { return getModifier() == NonIsolatedModifier::Unsafe; }
+  bool isNonSending() const {
+    return getModifier() == NonIsolatedModifier::NonSending;
+  }
 
-  bool isUnsafe() const { return Bits.NonisolatedAttr.isUnsafe; }
+  static NonisolatedAttr *
+  createImplicit(ASTContext &ctx,
+                 NonIsolatedModifier modifier = NonIsolatedModifier::None) {
+    return new (ctx) NonisolatedAttr(/*atLoc*/ {}, /*range*/ {}, modifier,
+                                     /*implicit=*/true);
+  }
 
   static bool classof(const DeclAttribute *DA) {
     return DA->getKind() == DeclAttrKind::Nonisolated;
@@ -2996,11 +3205,55 @@ class NonisolatedAttr final : public DeclAttribute {
 
   /// Create a copy of this attribute.
   NonisolatedAttr *clone(ASTContext &ctx) const {
-    return new (ctx) NonisolatedAttr(AtLoc, Range, isUnsafe(), isImplicit());
+    return new (ctx) NonisolatedAttr(AtLoc, Range, getModifier(), isImplicit());
   }
 
   bool isEquivalent(const NonisolatedAttr *other, Decl *attachedTo) const {
-    return isUnsafe() == other->isUnsafe();
+    return getModifier() == other->getModifier();
+  }
+};
+
+/// Represents @_inheritActorContext modifier.
+class InheritActorContextAttr final : public DeclAttribute {
+public:
+  InheritActorContextAttr(SourceLoc atLoc, SourceRange range,
+                          InheritActorContextModifier modifier, bool implicit)
+      : DeclAttribute(DeclAttrKind::InheritActorContext, atLoc, range,
+                      implicit) {
+    Bits.InheritActorContextAttr.Modifier = static_cast<unsigned>(modifier);
+    assert((getModifier() == modifier) && "not enough bits for modifier");
+  }
+
+  InheritActorContextModifier getModifier() const {
+    return static_cast<InheritActorContextModifier>(
+        Bits.InheritActorContextAttr.Modifier);
+  }
+
+  bool isAlways() const {
+    return getModifier() == InheritActorContextModifier::Always;
+  }
+
+  static InheritActorContextAttr *
+  createImplicit(ASTContext &ctx, InheritActorContextModifier modifier =
+                                      InheritActorContextModifier::None) {
+    return new (ctx)
+        InheritActorContextAttr(/*atLoc*/ {}, /*range*/ {}, modifier,
+                                /*implicit=*/true);
+  }
+
+  static bool classof(const DeclAttribute *DA) {
+    return DA->getKind() == DeclAttrKind::InheritActorContext;
+  }
+
+  /// Create a copy of this attribute.
+  InheritActorContextAttr *clone(ASTContext &ctx) const {
+    return new (ctx)
+        InheritActorContextAttr(AtLoc, Range, getModifier(), isImplicit());
+  }
+
+  bool isEquivalent(const InheritActorContextAttr *other,
+                    Decl *attachedTo) const {
+    return getModifier() == other->getModifier();
   }
 };
 
@@ -3171,26 +3424,33 @@ class LifetimeAttr final : public DeclAttribute {
   LifetimeEntry *entry;
 
   LifetimeAttr(SourceLoc atLoc, SourceRange baseRange, bool implicit,
-               LifetimeEntry *entry)
+               LifetimeEntry *entry, bool isUnderscored)
       : DeclAttribute(DeclAttrKind::Lifetime, atLoc, baseRange, implicit),
-        entry(entry) {}
+        entry(entry) {
+    Bits.LifetimeAttr.isUnderscored = isUnderscored;
+  }
 
 public:
   static LifetimeAttr *create(ASTContext &context, SourceLoc atLoc,
                               SourceRange baseRange, bool implicit,
-                              LifetimeEntry *entry);
+                              LifetimeEntry *entry, bool isUnderscored);
 
   LifetimeEntry *getLifetimeEntry() const { return entry; }
 
+  bool isUnderscored() const { return bool(Bits.LifetimeAttr.isUnderscored); }
+
   static bool classof(const DeclAttribute *DA) {
     return DA->getKind() == DeclAttrKind::Lifetime;
   }
 
   /// Create a copy of this attribute.
   LifetimeAttr *clone(ASTContext &ctx) const {
-    return new (ctx) LifetimeAttr(AtLoc, Range, isImplicit(), entry);
+    return new (ctx)
+        LifetimeAttr(AtLoc, Range, isImplicit(), entry, isUnderscored());
   }
 
+  std::string getString() const;
+
   bool isEquivalent(const LifetimeAttr *other, Decl *attachedTo) const;
 };
 
@@ -3231,8 +3491,8 @@ class AllowFeatureSuppressionAttr final
   bool getInverted() const { return Bits.AllowFeatureSuppressionAttr.Inverted; }
 
   ArrayRef<Identifier> getSuppressedFeatures() const {
-    return {getTrailingObjects<Identifier>(),
-            static_cast<size_t>(Bits.AllowFeatureSuppressionAttr.NumFeatures)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.AllowFeatureSuppressionAttr.NumFeatures));
   }
 
   static bool classof(const DeclAttribute *DA) {
@@ -3275,34 +3535,39 @@ class ABIAttr : public DeclAttribute {
   }
 };
 
-class ExecutionAttr : public DeclAttribute {
+/// Defines a @nonexhaustive attribute.
+class NonexhaustiveAttr : public DeclAttribute {
 public:
-  ExecutionAttr(SourceLoc AtLoc, SourceRange Range,
-                ExecutionKind behavior,
-                bool Implicit)
-      : DeclAttribute(DeclAttrKind::Execution, AtLoc, Range, Implicit) {
-    Bits.ExecutionAttr.Behavior = static_cast<uint8_t>(behavior);
+  NonexhaustiveAttr(SourceLoc atLoc, SourceRange range, NonexhaustiveMode mode,
+                    bool implicit = false)
+      : DeclAttribute(DeclAttrKind::Nonexhaustive, atLoc, range, implicit) {
+    Bits.NonexhaustiveAttr.mode = unsigned(mode);
   }
 
-  ExecutionAttr(ExecutionKind behavior, bool Implicit)
-      : ExecutionAttr(/*AtLoc=*/SourceLoc(), /*Range=*/SourceRange(), behavior,
-                      Implicit) {}
+  NonexhaustiveAttr(NonexhaustiveMode mode)
+    : NonexhaustiveAttr(SourceLoc(), SourceRange(), mode) {}
 
-  ExecutionKind getBehavior() const {
-    return static_cast<ExecutionKind>(Bits.ExecutionAttr.Behavior);
+  NonexhaustiveMode getMode() const {
+    return NonexhaustiveMode(Bits.NonexhaustiveAttr.mode);
   }
 
   static bool classof(const DeclAttribute *DA) {
-    return DA->getKind() == DeclAttrKind::Execution;
+    return DA->getKind() == DeclAttrKind::Nonexhaustive;
   }
 
-  UNIMPLEMENTED_CLONE(ExecutionAttr)
+  NonexhaustiveAttr *clone(ASTContext &ctx) const {
+    return new (ctx) NonexhaustiveAttr(AtLoc, Range, getMode(), isImplicit());
+  }
 
-  bool isEquivalent(const ExecutionAttr *other, Decl *attachedTo) const {
-    return getBehavior() == other->getBehavior();
+  bool isEquivalent(const NonexhaustiveAttr *other, Decl *attachedTo) const {
+    return getMode() == other->getMode();
   }
 };
 
+
+/// The kind of unary operator, if any.
+enum class UnaryOperatorKind : uint8_t { None, Prefix, Postfix };
+
 /// Attributes that may be applied to declarations.
 class DeclAttributes {
   /// Linked list of declaration attributes.
@@ -3605,13 +3870,23 @@ class SemanticAvailableAttr final {
   /// The source range of the `introduced:` version component.
   SourceRange getIntroducedSourceRange() const { return attr->IntroducedRange; }
 
-  /// Returns the effective introduction range indicated by this attribute.
-  /// This may correspond to the version specified by the `introduced:`
-  /// component (remapped or canonicalized if necessary) or it may be "always"
-  /// for an attribute indicating availability in a version-less domain. Returns
-  /// `std::nullopt` if the attribute does not indicate introduction.
+  /// See `getIntroducedDomainAndRange()`.
   std::optional<AvailabilityRange>
-  getIntroducedRange(const ASTContext &Ctx) const;
+  getIntroducedRange(const ASTContext &ctx) const {
+    if (auto domainAndRange = getIntroducedDomainAndRange(ctx))
+      return domainAndRange->getRange();
+    return std::nullopt;
+  }
+
+  /// Returns the effective introduction range indicated by this attribute,
+  /// along with the domain that it applies to (which may be different than the
+  /// domain which the attribute was written with if a remap is required). This
+  /// may correspond to the version specified by the `introduced:` component
+  /// (remapped or canonicalized if necessary) or it may be "always" for an
+  /// attribute indicating availability in a version-less domain. Returns
+  /// `std::nullopt` if the attribute does not indicate introduction.
+  std::optional<AvailabilityDomainAndRange>
+  getIntroducedDomainAndRange(const ASTContext &ctx) const;
 
   /// The version tuple for the `deprecated:` component.
   std::optional<llvm::VersionTuple> getDeprecated() const;
@@ -3619,13 +3894,23 @@ class SemanticAvailableAttr final {
   /// The source range of the `deprecated:` version component.
   SourceRange getDeprecatedSourceRange() const { return attr->DeprecatedRange; }
 
-  /// Returns the effective deprecation range indicated by this attribute.
-  /// This may correspond to the version specified by the `deprecated:`
-  /// component (remapped or canonicalized if necessary) or it may be "always"
-  /// for an unconditional deprecation attribute. Returns `std::nullopt` if the
-  /// attribute does not indicate deprecation.
+  /// See `getDeprecatedDomainAndRange()`.
   std::optional<AvailabilityRange>
-  getDeprecatedRange(const ASTContext &Ctx) const;
+  getDeprecatedRange(const ASTContext &ctx) const {
+    if (auto domainAndRange = getDeprecatedDomainAndRange(ctx))
+      return domainAndRange->getRange();
+    return std::nullopt;
+  }
+
+  /// Returns the effective deprecation range indicated by this attribute, along
+  /// with the domain that it applies to (which may be different than the domain
+  /// which the attribute was written with if a remap is required). This may
+  /// correspond to the version specified by the `deprecated:` component
+  /// (remapped or canonicalized if necessary) or it may be "always" for an
+  /// unconditional deprecation attribute. Returns `std::nullopt` if the
+  /// attribute does not indicate deprecation.
+  std::optional<AvailabilityDomainAndRange>
+  getDeprecatedDomainAndRange(const ASTContext &ctx) const;
 
   /// The version tuple for the `obsoleted:` component.
   std::optional<llvm::VersionTuple> getObsoleted() const;
@@ -3633,13 +3918,23 @@ class SemanticAvailableAttr final {
   /// The source range of the `obsoleted:` version component.
   SourceRange getObsoletedSourceRange() const { return attr->ObsoletedRange; }
 
-  /// Returns the effective obsoletion range indicated by this attribute.
-  /// This always corresponds to the version specified by the `obsoleted:`
-  /// component (remapped or canonicalized if necessary). Returns `std::nullopt`
-  /// if the attribute does not indicate obsoletion (note that unavailability is
-  /// separate from obsoletion.
+  /// See `getObsoletedDomainAndRange()`.
   std::optional<AvailabilityRange>
-  getObsoletedRange(const ASTContext &Ctx) const;
+  getObsoletedRange(const ASTContext &ctx) const {
+    if (auto domainAndRange = getObsoletedDomainAndRange(ctx))
+      return domainAndRange->getRange();
+    return std::nullopt;
+  }
+
+  /// Returns the effective obsoletion range indicated by this attribute, along
+  /// with the domain that it applies to (which may be different than the domain
+  /// which the attribute was written with if a remap is required). This may
+  /// correspond to the version specified by the `obsoleted:` component
+  /// (remapped or canonicalized if necessary) or it may be "always" if the
+  /// attribute represents unconditional unavailability. Returns `std::nullopt`
+  /// if the attribute does not indicate obsoletion.
+  std::optional<AvailabilityDomainAndRange>
+  getObsoletedDomainAndRange(const ASTContext &ctx) const;
 
   /// Returns the `message:` field of the attribute, or an empty string.
   StringRef getMessage() const { return attr->Message; }
@@ -3677,7 +3972,7 @@ class SemanticAvailableAttr final {
 
   /// Whether this is a language mode specific attribute.
   bool isSwiftLanguageModeSpecific() const {
-    return getDomain().isSwiftLanguage() && isVersionSpecific();
+    return getDomain().isSwiftLanguageMode() && isVersionSpecific();
   }
 
   /// Whether this is a PackageDescription version specific attribute.
@@ -3762,10 +4057,6 @@ class alignas(1 << AttrAlignInBits) TypeAttribute
     SWIFT_INLINE_BITFIELD_FULL(IsolatedTypeAttr, TypeAttribute, 8,
       Kind : 8
     );
-
-    SWIFT_INLINE_BITFIELD_FULL(ExecutionTypeAttr, TypeAttribute, 8,
-      Behavior : 8
-    );
   } Bits;
   // clang-format on
 
@@ -3781,6 +4072,10 @@ class alignas(1 << AttrAlignInBits) TypeAttribute
   TypeAttrKind getKind() const {
     return TypeAttrKind(Bits.TypeAttribute.Kind);
   }
+
+  /// - Note: Do not call this directly when emitting a diagnostic. Instead,
+  /// define the diagnostic to accept a `const TypeAttribute *` and use the
+  /// appropriate format specifier.
   const char *getAttrName() const {
     return getAttrName(getKind());
   }
@@ -4033,28 +4328,6 @@ class IsolatedTypeAttr : public SimpleTypeAttrWithArgs<TypeAttrKind::Isolated> {
   void printImpl(ASTPrinter &printer, const PrintOptions &options) const;
 };
 
-/// The @execution function type attribute.
-class ExecutionTypeAttr : public SimpleTypeAttrWithArgs<TypeAttrKind::Execution> {
-  SourceLoc BehaviorLoc;
-
-public:
-  ExecutionTypeAttr(SourceLoc atLoc, SourceLoc kwLoc, SourceRange parensRange,
-                    Located<ExecutionKind> behavior)
-      : SimpleTypeAttr(atLoc, kwLoc, parensRange), BehaviorLoc(behavior.Loc) {
-    Bits.ExecutionTypeAttr.Behavior = uint8_t(behavior.Item);
-  }
-
-  ExecutionKind getBehavior() const {
-    return ExecutionKind(Bits.ExecutionTypeAttr.Behavior);
-  }
-
-  SourceLoc getBehaviorLoc() const {
-    return BehaviorLoc;
-  }
-
-  void printImpl(ASTPrinter &printer, const PrintOptions &options) const;
-};
-
 using TypeOrCustomAttr =
   llvm::PointerUnion<CustomAttr*, TypeAttribute*>;
 
diff --git a/include/swift/AST/AttrKind.h b/include/swift/AST/AttrKind.h
index d56edbc4b6e31..271f90d31b662 100644
--- a/include/swift/AST/AttrKind.h
+++ b/include/swift/AST/AttrKind.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -17,151 +17,156 @@
 #ifndef SWIFT_ATTRKIND_H
 #define SWIFT_ATTRKIND_H
 
-#include "swift/Basic/InlineBitfield.h"
-#include "swift/Basic/LLVM.h"
-#include "swift/Config.h"
-#include "llvm/Support/DataTypes.h"
+/// `AttrKind.h` is imported into Swift. Be *very* careful with what you
+/// include here and keep these includes minimal!
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
+#include "swift/Basic/SwiftBridging.h"
+#include <stdint.h>
+
+namespace llvm {
+class StringRef;
+}
 
 namespace swift {
 
 /// The associativity of a binary operator.
-enum class Associativity : uint8_t {
+enum class ENUM_EXTENSIBILITY_ATTR(closed) Associativity : uint8_t {
   /// Non-associative operators cannot be written next to other
   /// operators with the same precedence.  Relational operators are
   /// typically non-associative.
-  None,
+  None SWIFT_NAME("none"),
 
   /// Left-associative operators associate to the left if written next
   /// to other left-associative operators of the same precedence.
-  Left,
+  Left SWIFT_NAME("left"),
 
   /// Right-associative operators associate to the right if written
   /// next to other right-associative operators of the same precedence.
-  Right
+  Right SWIFT_NAME("right")
 };
 
 /// Returns the in-source spelling of the given associativity.
-StringRef getAssociativitySpelling(Associativity value);
-
-/// The kind of unary operator, if any.
-enum class UnaryOperatorKind : uint8_t {
-  None,
-  Prefix,
-  Postfix
-};
+SWIFT_UNAVAILABLE("Unavailable in Swift")
+llvm::StringRef getAssociativitySpelling(Associativity value);
 
 /// Access control levels.
 // These are used in diagnostics and with < and similar operations,
 // so please do not reorder existing values.
-enum class AccessLevel : uint8_t {
+enum class ENUM_EXTENSIBILITY_ATTR(closed) AccessLevel : uint8_t {
   /// Private access is limited to the current scope.
-  Private = 0,
+  Private SWIFT_NAME("private") = 0,
   /// File-private access is limited to the current file.
-  FilePrivate,
+  FilePrivate SWIFT_NAME("fileprivate"),
   /// Internal access is limited to the current module.
-  Internal,
+  Internal SWIFT_NAME("internal"),
   /// Package access is not limited, but some capabilities may be
   /// restricted outside of the current package containing modules.
   /// It's similar to Public in that it's accessible from other modules
   /// and subclassable only within the defining module as long as
   /// the modules are in the same package.
-  Package,
+  Package SWIFT_NAME("package"),
   /// Public access is not limited, but some capabilities may be
   /// restricted outside of the current module.
-  Public,
+  Public SWIFT_NAME("public"),
   /// Open access is not limited, and all capabilities are unrestricted.
-  Open,
+  Open SWIFT_NAME("open"),
 };
 
 /// Returns the in-source spelling of the given access level.
-StringRef getAccessLevelSpelling(AccessLevel value);
+SWIFT_UNAVAILABLE("Unavailable in Swift")
+llvm::StringRef getAccessLevelSpelling(AccessLevel value);
 
-enum class InlineKind : uint8_t {
-  Never = 0,
-  Always = 1,
+enum class ENUM_EXTENSIBILITY_ATTR(closed) InlineKind : uint8_t {
+  Never SWIFT_NAME("never") = 0,
+  AlwaysUnderscored SWIFT_NAME("alwaysUnderscored") = 1,
+  Always SWIFT_NAME("always") = 2,
   Last_InlineKind = Always
 };
 
-enum : unsigned { NumInlineKindBits =
-  countBitsUsed(static_cast<unsigned>(InlineKind::Last_InlineKind)) };
-
-
 /// This enum represents the possible values of the @_effects attribute.
 /// These values are ordered from the strongest guarantee to the weakest,
 /// so please do not reorder existing values.
-enum class EffectsKind : uint8_t {
-  ReadNone,
-  ReadOnly,
-  ReleaseNone,
-  ReadWrite,
-  Unspecified,
-  Custom,
-  Last_EffectsKind = Unspecified
+enum class ENUM_EXTENSIBILITY_ATTR(closed) EffectsKind : uint8_t {
+  ReadNone SWIFT_NAME("readnone"),
+  ReadOnly SWIFT_NAME("readonly"),
+  ReleaseNone SWIFT_NAME("releasenone"),
+  ReadWrite SWIFT_NAME("readwrite"),
+  Unspecified SWIFT_NAME("unspecified"),
+  Custom SWIFT_NAME("custom"),
+  Last_EffectsKind = Custom
 };
 
-enum : unsigned { NumEffectsKindBits =
-  countBitsUsed(static_cast<unsigned>(EffectsKind::Last_EffectsKind)) };
-
 /// This enum represents the possible values of the @_expose attribute.
-enum class ExposureKind: uint8_t {
-  Cxx,
-  Wasm,
+enum class ENUM_EXTENSIBILITY_ATTR(closed) ExposureKind : uint8_t {
+  Cxx SWIFT_NAME("cxx"),
+  NotCxx SWIFT_NAME("notcxx"),
+  Wasm SWIFT_NAME("wasm"),
   Last_ExposureKind = Wasm
 };
 
-enum : unsigned { NumExposureKindBits =
-  countBitsUsed(static_cast<unsigned>(ExposureKind::Last_ExposureKind)) };
-  
 /// This enum represents the possible values of the @_extern attribute.
-enum class ExternKind: uint8_t {
+enum class ENUM_EXTENSIBILITY_ATTR(closed) ExternKind : uint8_t {
   /// Reference an externally defined C function.
   /// The imported function has C function pointer representation,
   /// and is called using the C calling convention.
-  C,
+  C SWIFT_NAME("c"),
   /// Reference an externally defined function through WebAssembly's
   /// import mechanism.
   /// This does not specify the calling convention and can be used
   /// with other extern kinds together.
   /// Effectively, this is no-op on non-WebAssembly targets.
-  Wasm,
+  Wasm SWIFT_NAME("wasm"),
   Last_ExternKind = Wasm
 };
 
-enum : unsigned { NumExternKindBits =
-  countBitsUsed(static_cast<unsigned>(ExternKind::Last_ExternKind)) };
-
-enum class ExecutionKind : uint8_t {
-  Concurrent = 0,
-  Caller,
-  Last_ExecutionKind = Caller
+enum class ENUM_EXTENSIBILITY_ATTR(closed) NonIsolatedModifier : uint8_t {
+  None SWIFT_NAME("none") = 0,
+  Unsafe SWIFT_NAME("unsafe"),
+  NonSending SWIFT_NAME("nonsending"),
+  Last_NonIsolatedModifier = NonSending
 };
 
-enum : unsigned { NumExecutionKindBits =
-  countBitsUsed(static_cast<unsigned>(ExecutionKind::Last_ExecutionKind)) };
+enum class ENUM_EXTENSIBILITY_ATTR(closed)
+    InheritActorContextModifier : uint8_t {
+      /// Inherit the actor execution context if the isolated parameter was
+      /// captured by the closure, context is nonisolated or isolated to a
+      /// global actor.
+      None SWIFT_NAME("none") = 0,
+      /// Always inherit the actor context, even when the isolated parameter
+      /// for the context is not closed over explicitly.
+      Always SWIFT_NAME("always"),
+      Last_InheritActorContextKind = Always
+    };
+
+enum class ENUM_EXTENSIBILITY_ATTR(closed) NonexhaustiveMode : uint8_t {
+  Error SWIFT_NAME("error") = 0,
+  Warning SWIFT_NAME("warning") = 1,
+  Last_NonexhaustiveMode = Warning
+};
 
-enum class DeclAttrKind : unsigned {
+enum class ENUM_EXTENSIBILITY_ATTR(closed) DeclAttrKind : unsigned {
 #define DECL_ATTR(_, CLASS, ...) CLASS,
 #define LAST_DECL_ATTR(CLASS) Last_DeclAttr = CLASS,
 #include "swift/AST/DeclAttr.def"
 };
 
-StringRef getDeclAttrKindID(DeclAttrKind kind);
+SWIFT_UNAVAILABLE("Unavailable in Swift")
+llvm::StringRef getDeclAttrKindID(DeclAttrKind kind);
 
 enum : unsigned {
-  NumDeclAttrKinds = static_cast<unsigned>(DeclAttrKind::Last_DeclAttr) + 1,
-  NumDeclAttrKindBits = countBitsUsed(NumDeclAttrKinds - 1),
+  NumDeclAttrKinds = static_cast<unsigned>(DeclAttrKind::Last_DeclAttr) + 1
 };
 
 // Define enumerators for each type attribute, e.g. TypeAttrKind::Weak.
-enum class TypeAttrKind {
+enum class ENUM_EXTENSIBILITY_ATTR(closed) TypeAttrKind {
 #define TYPE_ATTR(_, CLASS) CLASS,
 #define LAST_TYPE_ATTR(CLASS) Last_TypeAttr = CLASS,
 #include "swift/AST/TypeAttr.def"
 };
 
 enum : unsigned {
-  NumTypeAttrKinds = static_cast<unsigned>(TypeAttrKind::Last_TypeAttr) + 1,
-  NumTypeAttrKindBits = countBitsUsed(NumTypeAttrKinds - 1),
+  NumTypeAttrKinds = static_cast<unsigned>(TypeAttrKind::Last_TypeAttr) + 1
 };
 
 } // end namespace swift
diff --git a/include/swift/AST/AutoDiff.h b/include/swift/AST/AutoDiff.h
index d4d2574882b6c..28f24ffb6f528 100644
--- a/include/swift/AST/AutoDiff.h
+++ b/include/swift/AST/AutoDiff.h
@@ -422,7 +422,14 @@ class DerivativeFunctionTypeError
   Kind kind;
 
   /// The type and index of a differentiability parameter or result.
-  using TypeAndIndex = std::pair<Type, unsigned>;
+  /// std::pair does not have a trivial copy constructor on FreeBSD for
+  /// ABI reasons, so we have to define our own type here instead
+  struct TypeAndIndex {
+    Type first;
+    unsigned second;
+
+    TypeAndIndex(Type type, unsigned index) : first(type), second(index) {}
+  };
 
 private:
   union Value {
diff --git a/include/swift/AST/AvailabilityConstraint.h b/include/swift/AST/AvailabilityConstraint.h
index ba9e70230dfc1..807078f729e90 100644
--- a/include/swift/AST/AvailabilityConstraint.h
+++ b/include/swift/AST/AvailabilityConstraint.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2024 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -20,9 +20,10 @@
 #include "swift/AST/Attr.h"
 #include "swift/AST/AvailabilityDomain.h"
 #include "swift/AST/AvailabilityRange.h"
-#include "swift/AST/PlatformKind.h"
+#include "swift/AST/PlatformKindUtils.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/OptionSet.h"
+#include "llvm/Support/raw_ostream.h"
 
 namespace swift {
 
@@ -30,52 +31,96 @@ class ASTContext;
 class AvailabilityContext;
 class Decl;
 
-/// Represents the reason a declaration could be considered unavailable in a
-/// certain context.
+/// Represents the reason a declaration is considered not available in a
+/// specific `AvailabilityContext`.
 class AvailabilityConstraint {
 public:
-  /// The reason that the availability constraint is unsatisfied.
+  /// The reason that a declaration is not available in a context. Broadly, the
+  /// declaration may either be "unintroduced" or "unavailable" depending on its
+  /// `@available` attributes. A declaration that is unintroduced can become
+  /// available if availability constraints are added to the context. For
+  /// unavailable declarations, on the other hand, either changing the
+  /// deployment target or making the context itself unavailable are necessary
+  /// to satisfy the constraint.
+  ///
+  /// For example, take the following declaration `f()`:
+  ///
+  ///     @available(macOS, introduced: 11.0, obsoleted: 14.0)
+  ///     func f() { ... }
+  ///
+  /// In contexts that may run on earlier OSes, references to `f()` yield
+  /// an `Unintroduced` constraint:
+  ///
+  ///     @available(macOS 10.15, *)
+  ///     func g() {
+  ///       f() // error: 'f()' is only available in macOS 11.0 or newer
+  ///     }
+  ///
+  ///     macOS ...            11.0                   14.0               ...
+  ///     f()   |----------------[=======================)-----------------|
+  ///     g()   |-----------[==============================================)
+  ///                       ^
+  ///                  Unintroduced
+  ///
+  /// On the other hand, in contexts where deployment target is high enough to
+  /// make `f()` obsolete, references to it yield an `UnavailableObsolete`
+  /// constraint:
+  ///
+  ///     // compiled with -target arm64-apple-macos14
+  ///     func h() {
+  ///       f() // error: 'f()' is unavailable in macOS
+  ///     }
+  ///
+  ///     macOS ...            11.0                    14.0              ...
+  ///     f()   |----------------[=======================)-----------------|
+  ///     h()   |----------------------------------------[=================)
+  ///                                                    ^
+  ///                                           UnavailableObsolete
+  ///
+  /// References to declarations that are unavailable in all versions of a
+  /// domain generate `UnavailableUnconditional` constraints unless the context
+  /// is also unavailable under the same conditions:
+  ///
+  ///     @available(macOS, unavailable)
+  ///     func foo() { ... }
+  ///
+  ///     func bar() {
+  ///       foo() // error: 'foo()' is unavailable in macOS
+  ///     }
+  ///
+  ///     @available(macOS, unavailable)
+  ///     func baz() {
+  ///       foo() // OK
+  ///     }
+  ///
+  ///     @available(*, unavailable)
+  ///     func qux() {
+  ///       foo() // also OK
+  ///     }
   ///
   /// NOTE: The order of this enum matters. Reasons are defined in descending
   /// priority order.
   enum class Reason {
-    /// The declaration is referenced in a context in which it is generally
-    /// unavailable. For example, a reference to a declaration that is
-    /// unavailable on macOS from a context that may execute on macOS has this
-    /// constraint.
-    UnconditionallyUnavailable,
-
-    /// The declaration is referenced in a context in which it is considered
-    /// obsolete. For example, a reference to a declaration that is obsolete in
-    /// macOS 13 from a context that may execute on macOS 13 or later has this
-    /// constraint.
-    Obsoleted,
-
-    /// The declaration is not available in the deployment configuration
-    /// specified for this compilation. For example, the declaration might only
-    /// be introduced in the Swift 6 language mode while the module is being
-    /// compiled in the Swift 5 language mode. These availability constraints
-    /// cannot be satisfied by adding constraining contextual availability using
-    /// `@available` attributes or `if #available` queries.
-    UnavailableForDeployment,
-
-    /// The declaration is referenced in a context that does not have adequate
-    /// availability constraints. For example, a reference to a declaration that
-    /// was introduced in macOS 13 from a context that may execute on earlier
-    /// versions of macOS cannot satisfy this constraint. The constraint
-    /// can be satisfied, though, by introducing an `@available` attribute or an
-    /// `if #available(...)` query.
-    PotentiallyUnavailable,
-  };
+    /// The declaration is unconditionally unavailable, e.g. because of
+    /// `@available(macOS, unavailable)`.
+    UnavailableUnconditionally,
 
-  /// Classifies constraints into different high level categories.
-  enum class Kind {
-    /// There are no contexts in which the declaration would be available.
-    Unavailable,
+    /// The declaration is obsolete, e.g. because of
+    /// `@available(macOS, obsolete: 14.0)` in a program with a deployment
+    /// target of `macOS 14` or later.
+    UnavailableObsolete,
 
-    /// There are some contexts in which the declaration would be available if
-    /// additional constraints were added.
-    PotentiallyAvailable,
+    /// The declaration is only available for later deployment configurations,
+    /// e.g. because of `@available(swift 6)` in a program compiled with
+    /// `-swift-version 5`.
+    UnavailableUnintroduced,
+
+    /// The declaration has not yet been introduced, e.g. because of
+    /// `@available(macOS 14, *)` in a context that may run on macOS 13 or
+    /// later. The constraint may be satisfied adding an `@available` attribute
+    /// or an `if #available(...)` query with sufficient introduction
+    /// constraints to the context.
+    Unintroduced,
   };
 
 private:
@@ -86,22 +131,22 @@ class AvailabilityConstraint {
 
 public:
   static AvailabilityConstraint
-  unconditionallyUnavailable(SemanticAvailableAttr attr) {
-    return AvailabilityConstraint(Reason::UnconditionallyUnavailable, attr);
+  unavailableUnconditionally(SemanticAvailableAttr attr) {
+    return AvailabilityConstraint(Reason::UnavailableUnconditionally, attr);
   }
 
-  static AvailabilityConstraint obsoleted(SemanticAvailableAttr attr) {
-    return AvailabilityConstraint(Reason::Obsoleted, attr);
+  static AvailabilityConstraint
+  unavailableObsolete(SemanticAvailableAttr attr) {
+    return AvailabilityConstraint(Reason::UnavailableObsolete, attr);
   }
 
   static AvailabilityConstraint
-  unavailableForDeployment(SemanticAvailableAttr attr) {
-    return AvailabilityConstraint(Reason::UnavailableForDeployment, attr);
+  unavailableUnintroduced(SemanticAvailableAttr attr) {
+    return AvailabilityConstraint(Reason::UnavailableUnintroduced, attr);
   }
 
-  static AvailabilityConstraint
-  potentiallyUnavailable(SemanticAvailableAttr attr) {
-    return AvailabilityConstraint(Reason::PotentiallyUnavailable, attr);
+  static AvailabilityConstraint unintroduced(SemanticAvailableAttr attr) {
+    return AvailabilityConstraint(Reason::Unintroduced, attr);
   }
 
   Reason getReason() const { return attrAndReason.getInt(); }
@@ -109,37 +154,32 @@ class AvailabilityConstraint {
     return static_cast<SemanticAvailableAttr>(attrAndReason.getPointer());
   }
 
-  Kind getKind() const {
+  /// Returns true if the constraint cannot be satisfied using a runtime
+  /// availability query (`if #available(...)`).
+  bool isUnavailable() const {
     switch (getReason()) {
-    case Reason::UnconditionallyUnavailable:
-    case Reason::Obsoleted:
-    case Reason::UnavailableForDeployment:
-      return Kind::Unavailable;
-    case Reason::PotentiallyUnavailable:
-      return Kind::PotentiallyAvailable;
+    case Reason::UnavailableUnconditionally:
+    case Reason::UnavailableObsolete:
+    case Reason::UnavailableUnintroduced:
+      return true;
+    case Reason::Unintroduced:
+      return false;
     }
   }
 
-  /// Returns true if the constraint cannot be satisfied at runtime.
-  bool isUnavailable() const { return getKind() == Kind::Unavailable; }
-
-  /// Returns true if the constraint is unsatisfied but could be satisfied at
-  /// runtime in a more constrained context.
-  bool isPotentiallyAvailable() const {
-    return getKind() == Kind::PotentiallyAvailable;
-  }
-
   /// Returns the domain that the constraint applies to.
   AvailabilityDomain getDomain() const { return getAttr().getDomain(); }
 
-  /// Returns the required range for `IntroducedInNewerVersion` requirements, or
-  /// `std::nullopt` otherwise.
-  std::optional<AvailabilityRange>
-  getPotentiallyUnavailableRange(const ASTContext &ctx) const;
+  /// Returns the domain and range (remapped if necessary) in which the
+  /// constraint must be satisfied. How the range should be interpreted depends
+  /// on the reason for the constraint.
+  AvailabilityDomainAndRange getDomainAndRange(const ASTContext &ctx) const;
 
   /// Some availability constraints are active for type-checking but cannot
   /// be translated directly into an `if #available(...)` runtime query.
   bool isActiveForRuntimeQueries(const ASTContext &ctx) const;
+
+  void print(raw_ostream &os) const;
 };
 
 /// Represents a set of availability constraints that restrict use of a
@@ -161,6 +201,8 @@ class DeclAvailabilityConstraints {
   using const_iterator = Storage::const_iterator;
   const_iterator begin() const { return constraints.begin(); }
   const_iterator end() const { return constraints.end(); }
+
+  void print(raw_ostream &os) const;
 };
 
 enum class AvailabilityConstraintFlag : uint8_t {
@@ -174,15 +216,55 @@ enum class AvailabilityConstraintFlag : uint8_t {
   /// Include constraints for all domains, regardless of whether they are active
   /// or relevant to type checking.
   IncludeAllDomains = 1 << 1,
+
+  /// By default, non-type declarations that are universally unavailable are
+  /// always diagnosed, regardless of whether the context of the reference
+  /// is also universally unavailable. If this flag is set, though, those
+  /// references are allowed.
+  AllowUniversallyUnavailableInCompatibleContexts = 1 << 2,
 };
 using AvailabilityConstraintFlags = OptionSet<AvailabilityConstraintFlag>;
 
-/// Returns the set of availability constraints that restrict use of \p decl
+/// Returns the set of availability constraints that restricts use of \p decl
 /// when it is referenced from the given context. In other words, it is the
-/// collection of of `@available` attributes with unsatisfied conditions.
+/// collection of `@available` attributes with unsatisfied conditions.
 DeclAvailabilityConstraints getAvailabilityConstraintsForDecl(
     const Decl *decl, const AvailabilityContext &context,
     AvailabilityConstraintFlags flags = std::nullopt);
+
+/// Returns the availability constraints that restricts use of \p decl
+/// in \p domain when it is referenced from the given context. In other words,
+/// it is the unsatisfied `@available` attribute  that applies to \p domain in
+/// the given context.
+std::optional<AvailabilityConstraint> getAvailabilityConstraintForDeclInDomain(
+    const Decl *decl, const AvailabilityContext &context,
+    AvailabilityDomain domain,
+    AvailabilityConstraintFlags flags = std::nullopt);
+
+/// Computes the set of constraints that indicate whether a decl is "runtime
+/// unavailable" (can never be reached at runtime) and adds the domain for each
+/// of those constraints to the \p domains vector.
+void getRuntimeUnavailableDomains(
+    const DeclAvailabilityConstraints &constraints,
+    llvm::SmallVectorImpl<AvailabilityDomain> &domains, const ASTContext &ctx);
+
 } // end namespace swift
 
+namespace llvm {
+
+inline llvm::raw_ostream &
+operator<<(llvm::raw_ostream &os,
+           const swift::AvailabilityConstraint &constraint) {
+  constraint.print(os);
+  return os;
+}
+
+inline llvm::raw_ostream &
+operator<<(llvm::raw_ostream &os,
+           const swift::DeclAvailabilityConstraints &constraints) {
+  constraints.print(os);
+  return os;
+}
+
+} // end namespace llvm
 #endif
diff --git a/include/swift/AST/AvailabilityContext.h b/include/swift/AST/AvailabilityContext.h
index 5bc3bfd3712ad..01b2cb3e1b6d5 100644
--- a/include/swift/AST/AvailabilityContext.h
+++ b/include/swift/AST/AvailabilityContext.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2024 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -20,9 +20,10 @@
 
 #include "swift/AST/AvailabilityDomain.h"
 #include "swift/AST/AvailabilityRange.h"
-#include "swift/AST/PlatformKind.h"
+#include "swift/AST/PlatformKindUtils.h"
 #include "swift/Basic/Debug.h"
 #include "swift/Basic/LLVM.h"
+#include "llvm/Support/raw_ostream.h"
 #include <optional>
 
 namespace swift {
@@ -75,6 +76,9 @@ class AvailabilityContext {
   /// of the given declaration.
   static AvailabilityContext forDeclSignature(const Decl *decl);
 
+  /// Returns the unconstrained availability context.
+  static AvailabilityContext forAlwaysAvailable(const ASTContext &ctx);
+
   /// Returns the range of platform versions which may execute code in the
   /// availability context, starting at its introduction version.
   // FIXME: [availability] Remove; superseded by getAvailableRange().
@@ -145,4 +149,14 @@ class AvailabilityContext {
 
 } // end namespace swift
 
+namespace llvm {
+
+inline llvm::raw_ostream &
+operator<<(llvm::raw_ostream &os, const swift::AvailabilityContext &context) {
+  context.print(os);
+  return os;
+}
+
+} // end namespace llvm
+
 #endif
diff --git a/include/swift/AST/AvailabilityContextStorage.h b/include/swift/AST/AvailabilityContextStorage.h
index a110d8ccdce1d..beae4a6df6ba1 100644
--- a/include/swift/AST/AvailabilityContextStorage.h
+++ b/include/swift/AST/AvailabilityContextStorage.h
@@ -82,7 +82,7 @@ class AvailabilityContext::Storage final
                             const ASTContext &ctx);
 
   llvm::ArrayRef<DomainInfo> getDomainInfos() const {
-    return llvm::ArrayRef(getTrailingObjects<DomainInfo>(), domainInfoCount);
+    return getTrailingObjects(domainInfoCount);
   }
 
   llvm::SmallVector<DomainInfo, 4> copyDomainInfos() const {
diff --git a/include/swift/AST/AvailabilityDomain.h b/include/swift/AST/AvailabilityDomain.h
index 8aa9266115c25..2318ddd06461f 100644
--- a/include/swift/AST/AvailabilityDomain.h
+++ b/include/swift/AST/AvailabilityDomain.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2024 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -21,19 +21,23 @@
 #include "swift/AST/ASTAllocated.h"
 #include "swift/AST/AvailabilityRange.h"
 #include "swift/AST/Identifier.h"
-#include "swift/AST/PlatformKind.h"
+#include "swift/AST/PlatformKindUtils.h"
+#include "swift/AST/TypeAlignments.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/SourceLoc.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/PointerEmbeddedInt.h"
 #include "llvm/ADT/PointerUnion.h"
+#include "llvm/Support/raw_ostream.h"
 
 namespace swift {
 class ASTContext;
 class CustomAvailabilityDomain;
 class DeclContext;
+class FuncDecl;
 class ModuleDecl;
+class ValueDecl;
 
 /// Represents a dimension of availability (e.g. macOS platform or Swift
 /// language mode).
@@ -45,7 +49,10 @@ class AvailabilityDomain final {
     Universal,
 
     /// Represents availability with respect to Swift language mode.
-    SwiftLanguage,
+    SwiftLanguageMode,
+
+    /// Represents availability with respect to the Swift runtime.
+    SwiftRuntime,
 
     /// Represents PackageDescription availability.
     PackageDescription,
@@ -117,9 +124,9 @@ class AvailabilityDomain final {
   AvailabilityDomain(Storage storage) : storage(storage) {};
 
   std::optional<InlineDomain> getInlineDomain() const {
-    return storage.is<InlineDomainPtr>()
+    return isa<InlineDomainPtr>(storage)
                ? static_cast<std::optional<InlineDomain>>(
-                     storage.get<InlineDomainPtr>())
+                     cast<InlineDomainPtr>(storage))
                : std::nullopt;
   }
 
@@ -136,8 +143,12 @@ class AvailabilityDomain final {
     return AvailabilityDomain(platformKind);
   }
 
-  static AvailabilityDomain forSwiftLanguage() {
-    return AvailabilityDomain(Kind::SwiftLanguage);
+  static AvailabilityDomain forSwiftLanguageMode() {
+    return AvailabilityDomain(Kind::SwiftLanguageMode);
+  }
+
+  static AvailabilityDomain forSwiftRuntime() {
+    return AvailabilityDomain(Kind::SwiftRuntime);
   }
 
   static AvailabilityDomain forPackageDescription() {
@@ -148,6 +159,10 @@ class AvailabilityDomain final {
     return AvailabilityDomain(Kind::Embedded);
   }
 
+  /// If `decl` represents an availability domain, returns the corresponding
+  /// `AvailabilityDomain` value. Otherwise, returns `std::nullopt`.
+  static std::optional<AvailabilityDomain> forCustom(ValueDecl *decl);
+
   static AvailabilityDomain forCustom(const CustomAvailabilityDomain *domain) {
     return AvailabilityDomain(domain);
   }
@@ -173,7 +188,11 @@ class AvailabilityDomain final {
 
   bool isPlatform() const { return getKind() == Kind::Platform; }
 
-  bool isSwiftLanguage() const { return getKind() == Kind::SwiftLanguage; }
+  bool isSwiftLanguageMode() const {
+    return getKind() == Kind::SwiftLanguageMode;
+  }
+
+  bool isSwiftRuntime() const { return getKind() == Kind::SwiftRuntime; }
 
   bool isPackageDescription() const {
     return getKind() == Kind::PackageDescription;
@@ -195,7 +214,7 @@ class AvailabilityDomain final {
   /// the domain. Returns `nullptr` otherwise.
   const CustomAvailabilityDomain *getCustomDomain() const {
     if (isCustom())
-      return storage.get<const CustomAvailabilityDomain *>();
+      return cast<const CustomAvailabilityDomain *>(storage);
     return nullptr;
   }
 
@@ -203,6 +222,10 @@ class AvailabilityDomain final {
   /// version ranges.
   bool isVersioned() const;
 
+  /// Returns true if the given version is a valid version number for this
+  /// domain. It is an error to call this on an un-versioned domain.
+  bool isVersionValid(const llvm::VersionTuple &version) const;
+
   /// Returns true if availability of the domain can be refined using
   /// `@available` attributes and `if #available` queries. If not, then the
   /// domain's availability is fixed by compilation settings. For example,
@@ -215,11 +238,16 @@ class AvailabilityDomain final {
 
   /// Returns true if this domain is considered active in the current
   /// compilation context.
-  bool isActive(const ASTContext &ctx) const;
+  bool isActive(const ASTContext &ctx, bool forTargetVariant = false) const;
 
   /// Returns true if this domain is a platform domain and is considered active
   /// in the current compilation context.
-  bool isActivePlatform(const ASTContext &ctx) const;
+  bool isActivePlatform(const ASTContext &ctx,
+                        bool forTargetVariant = false) const;
+
+  /// Returns true if availability in this domain must be specified alone in
+  /// `@available` attributes and `if #available` queries.
+  bool mustBeSpecifiedAlone() const;
 
   /// Returns the domain's minimum available range for type checking. For
   /// example, for the domain of the platform that compilation is targeting,
@@ -236,6 +264,10 @@ class AvailabilityDomain final {
   /// Returns the string to use when printing an `@available` attribute.
   llvm::StringRef getNameForAttributePrinting() const;
 
+  /// Returns the decl that represents the domain, or `nullptr` if the domain
+  /// does not have a decl.
+  ValueDecl *getDecl() const;
+
   /// Returns the module that the domain belongs to, if it is a custom domain.
   ModuleDecl *getModule() const;
 
@@ -244,6 +276,12 @@ class AvailabilityDomain final {
   /// universal domain (`*`) is the bottom element.
   bool contains(const AvailabilityDomain &other) const;
 
+  /// Returns true if availability in `other` is a subset of availability in
+  /// this domain or vice-versa.
+  bool isRelated(const AvailabilityDomain &other) const {
+    return contains(other) || other.contains(*this);
+  }
+
   /// Returns true for domains that are not contained by any domain other than
   /// the universal domain.
   bool isRoot() const;
@@ -253,6 +291,26 @@ class AvailabilityDomain final {
   /// descendants of the iOS domain.
   AvailabilityDomain getRootDomain() const;
 
+  /// Returns the canonical domain that versions in this domain must be remapped
+  /// to before making availability comparisons in the current compilation
+  /// context. Sets \p didRemap to `true` if a remap was required.
+  const AvailabilityDomain getRemappedDomain(const ASTContext &ctx,
+                                             bool &didRemap) const;
+
+  /// Returns the canonical domain that versions in this domain must be remapped
+  /// to before making availability comparisons in the current compilation
+  /// context.
+  const AvailabilityDomain getRemappedDomain(const ASTContext &ctx) const {
+    bool unused;
+    return getRemappedDomain(ctx, unused);
+  }
+
+  /// Returns true for a domain that is permanently always available, and
+  /// therefore availability constraints in the domain are effectively the same
+  /// as constraints in the `*` domain. This is used to diagnose unnecessary
+  /// `@available` attributes and `if #available` statements.
+  bool isPermanentlyAlwaysEnabled() const;
+
   bool operator==(const AvailabilityDomain &other) const {
     return storage.getOpaqueValue() == other.storage.getOpaqueValue();
   }
@@ -292,11 +350,15 @@ struct StableAvailabilityDomainComparator {
 };
 
 /// Represents an availability domain that has been defined in a module.
-class CustomAvailabilityDomain : public llvm::FoldingSetNode {
+class alignas(1 << CustomAvailabilityDomainAlignInBits) CustomAvailabilityDomain
+    : public llvm::FoldingSetNode {
 public:
-  enum class Kind {
+  enum class Kind : uint8_t {
     /// A domain that is known to be enabled at compile time.
     Enabled,
+    /// A domain that is known to be enabled at compile time and is also assumed
+    /// to be enabled for all deployments.
+    AlwaysEnabled,
     /// A domain that is known to be disabled at compile time.
     Disabled,
     /// A domain with an enablement state that must be queried at runtime.
@@ -305,28 +367,52 @@ class CustomAvailabilityDomain : public llvm::FoldingSetNode {
 
 private:
   Identifier name;
-  Kind kind;
   ModuleDecl *mod;
+  ValueDecl *decl;
+  FuncDecl *predicateFunc;
+  Kind kind;
+
+  struct {
+    /// Whether the "isPermanentlyEnabled" bit has been computed yet.
+    unsigned isPermanentlyEnabledComputed : 1;
+    /// Whether the domain is permanently enabled, which makes constraints in
+    /// the domain equivalent to those in the `*` domain.
+    unsigned isPermanentlyEnabled : 1;
+  } flags = {};
+
+  friend class IsCustomAvailabilityDomainPermanentlyEnabled;
 
-  CustomAvailabilityDomain(Identifier name, ModuleDecl *mod, Kind kind);
+  CustomAvailabilityDomain(Identifier name, Kind kind, ModuleDecl *mod,
+                           ValueDecl *decl, FuncDecl *predicateFunc);
 
 public:
-  static const CustomAvailabilityDomain *get(StringRef name, ModuleDecl *mod,
-                                             Kind kind, const ASTContext &ctx);
+  static const CustomAvailabilityDomain *get(StringRef name, Kind kind,
+                                             ModuleDecl *mod, ValueDecl *decl,
+                                             FuncDecl *predicateFunc,
+                                             const ASTContext &ctx);
 
   Identifier getName() const { return name; }
   Kind getKind() const { return kind; }
   ModuleDecl *getModule() const { return mod; }
+  ValueDecl *getDecl() const { return decl; }
+
+  /// Returns the function that should be called at runtime to determine whether
+  /// the domain is available, or `nullptr` if the domain's availability is not
+  /// determined at runtime.
+  FuncDecl *getPredicateFunc() const { return predicateFunc; }
 
   /// Uniquing for `ASTContext`.
   static void Profile(llvm::FoldingSetNodeID &ID, Identifier name,
-                      ModuleDecl *mod, Kind kind);
+                      ModuleDecl *mod);
 
-  void Profile(llvm::FoldingSetNodeID &ID) const {
-    Profile(ID, name, mod, kind);
-  }
+  void Profile(llvm::FoldingSetNodeID &ID) const { Profile(ID, name, mod); }
 };
 
+inline void simple_display(llvm::raw_ostream &os,
+                           const CustomAvailabilityDomain *domain) {
+  os << domain->getName();
+}
+
 /// Represents either a resolved availability domain or an identifier written
 /// in source that has not yet been resolved to a domain.
 class AvailabilityDomainOrIdentifier {
@@ -356,9 +442,9 @@ class AvailabilityDomainOrIdentifier {
       : storage(domain) {};
 
   bool isDomain() const {
-    return storage.getPointer().is<AvailabilityDomain>();
+    return isa<AvailabilityDomain>(storage.getPointer());
   }
-  bool isIdentifier() const { return storage.getPointer().is<Identifier>(); }
+  bool isIdentifier() const { return isa<Identifier>(storage.getPointer()); }
 
   /// Overwrites the existing domain or identifier with the given domain.
   void setDomain(AvailabilityDomain domain) { storage = Storage(domain); }
@@ -366,7 +452,7 @@ class AvailabilityDomainOrIdentifier {
   /// Returns the resolved domain, or `std::nullopt` if there isn't one.
   std::optional<AvailabilityDomain> getAsDomain() const {
     if (isDomain())
-      return storage.getPointer().get<AvailabilityDomain>();
+      return cast<AvailabilityDomain>(storage.getPointer());
     return std::nullopt;
   }
 
@@ -374,7 +460,7 @@ class AvailabilityDomainOrIdentifier {
   /// been resolved.
   std::optional<Identifier> getAsIdentifier() const {
     if (isIdentifier())
-      return storage.getPointer().get<Identifier>();
+      return cast<Identifier>(storage.getPointer());
     return std::nullopt;
   }
 
@@ -408,6 +494,20 @@ class AvailabilityDomainOrIdentifier {
   void print(llvm::raw_ostream &os) const;
 };
 
+/// Represents an `AvailabilityRange` paired with the `AvailabilityDomain` that
+/// the range applies to.
+class AvailabilityDomainAndRange {
+  AvailabilityDomain domain;
+  AvailabilityRange range;
+
+public:
+  AvailabilityDomainAndRange(AvailabilityDomain domain, AvailabilityRange range)
+      : domain(domain), range(range) {};
+
+  AvailabilityDomain getDomain() const { return domain; }
+  AvailabilityRange getRange() const { return range; }
+};
+
 } // end namespace swift
 
 namespace llvm {
@@ -469,6 +569,12 @@ struct PointerLikeTypeTraits<swift::AvailabilityDomainOrIdentifier> {
   };
 };
 
+inline llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
+                                     const swift::AvailabilityDomain &domain) {
+  domain.print(os);
+  return os;
+}
+
 } // end namespace llvm
 
 #endif
diff --git a/include/swift/AST/AvailabilityInference.h b/include/swift/AST/AvailabilityInference.h
index cfc9d871476c4..efb9fd7290fa2 100644
--- a/include/swift/AST/AvailabilityInference.h
+++ b/include/swift/AST/AvailabilityInference.h
@@ -31,10 +31,6 @@ class SemanticAvailableAttr;
 
 class AvailabilityInference {
 public:
-  /// Returns the decl that should be considered the parent decl of the given
-  /// decl when looking for inherited availability annotations.
-  static const Decl *parentDeclForInferredAvailability(const Decl *D);
-
   /// Infers the common availability required to access an array of
   /// declarations and adds attributes reflecting that availability
   /// to ToDecl.
@@ -47,9 +43,6 @@ class AvailabilityInference {
   /// Returns the range of platform versions in which the decl is available.
   static AvailabilityRange availableRange(const Decl *D);
 
-  /// Returns true is the declaration is `@_spi_available`.
-  static bool isAvailableAsSPI(const Decl *D);
-
   /// Returns the context for which the declaration
   /// is annotated as available, or None if the declaration
   /// has no availability annotation.
@@ -57,7 +50,7 @@ class AvailabilityInference {
   annotatedAvailableRange(const Decl *D);
 
   static AvailabilityRange
-  annotatedAvailableRangeForAttr(const Decl *D, const SpecializeAttr *attr,
+  annotatedAvailableRangeForAttr(const Decl *D, const AbstractSpecializeAttr *attr,
                                  ASTContext &ctx);
 
   /// For the attribute's introduction version, update the platform and version
@@ -81,11 +74,6 @@ class AvailabilityInference {
       const SemanticAvailableAttr &attr, const ASTContext &ctx,
       AvailabilityDomain &domain, llvm::VersionTuple &platformVer);
 
-  static void
-  updateAvailabilityDomainForFallback(const SemanticAvailableAttr &attr,
-                                      const ASTContext &ctx,
-                                      AvailabilityDomain &domain);
-
   /// For the attribute's before version, update the platform and version
   /// values to the re-mapped platform's, if using a fallback platform.
   /// Returns `true` if a remap occured.
diff --git a/include/swift/AST/AvailabilityQuery.h b/include/swift/AST/AvailabilityQuery.h
new file mode 100644
index 0000000000000..ca9f8af38e753
--- /dev/null
+++ b/include/swift/AST/AvailabilityQuery.h
@@ -0,0 +1,158 @@
+//===--- AvailabilityQuery.h - Swift Availability Query ASTs ----*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the availability query AST classes.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_AST_AVAILABILITY_QUERY_H
+#define SWIFT_AST_AVAILABILITY_QUERY_H
+
+#include "swift/AST/AvailabilityDomain.h"
+#include "swift/AST/AvailabilityRange.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/VersionTuple.h"
+
+namespace swift {
+class ASTContext;
+class FuncDecl;
+
+/// Represents the information needed to evaluate an `#if available` query
+/// (either at runtime or compile-time).
+class AvailabilityQuery final {
+  AvailabilityDomain domain;
+  std::optional<AvailabilityRange> primaryRange;
+  std::optional<AvailabilityRange> variantRange;
+
+  enum class ResultKind : uint8_t {
+    /// The result of the query is true at compile-time.
+    ConstTrue = 0,
+    /// The result of the query is false at compile-time.
+    ConstFalse = 1,
+    /// The result of the query must be determined at runtime.
+    Dynamic = 2,
+  };
+  ResultKind kind;
+
+  bool unavailable;
+
+  AvailabilityQuery(AvailabilityDomain domain, ResultKind kind,
+                    const std::optional<AvailabilityRange> &primaryRange,
+                    const std::optional<AvailabilityRange> &variantRange)
+      : domain(domain), primaryRange(primaryRange), variantRange(variantRange),
+        kind(kind), unavailable(false) {};
+
+public:
+  /// Returns an `AvailabilityQuery` for a query that evaluates to true or
+  /// false at compile-time.
+  static AvailabilityQuery constant(AvailabilityDomain domain, bool value) {
+    return AvailabilityQuery(
+        domain, value ? ResultKind::ConstTrue : ResultKind::ConstFalse,
+        std::nullopt, std::nullopt);
+  }
+
+  /// Returns an `AvailabilityQuery` for a query that evaluates to true or
+  /// false at compile-time in the universal availability domain.
+  static AvailabilityQuery universallyConstant(bool value) {
+    return AvailabilityQuery(AvailabilityDomain::forUniversal(),
+                             value ? ResultKind::ConstTrue
+                                   : ResultKind::ConstFalse,
+                             std::nullopt, std::nullopt);
+  }
+
+  /// Returns an `AvailabilityQuery` for a query that must be evaluated at
+  /// runtime with the given arguments, which may be zero, one, or two version
+  /// tuples that should be passed to the query function.
+  static AvailabilityQuery
+  dynamic(AvailabilityDomain domain,
+          const std::optional<AvailabilityRange> &primaryRange,
+          const std::optional<AvailabilityRange> &variantRange) {
+    return AvailabilityQuery(domain, ResultKind::Dynamic, primaryRange,
+                             variantRange);
+  }
+
+  /// Returns a copy of the `AvailabilityQuery` that has been modified to
+  /// represent an `if #unavailable` query if `isUnavailability` is true, or an
+  /// `if #available` query otherwise.
+  AvailabilityQuery asUnavailable(bool isUnavailability) const {
+    if (isUnavailability != unavailable) {
+      AvailabilityQuery copy = *this;
+      copy.unavailable = isUnavailability;
+      return copy;
+    }
+    return *this;
+  }
+
+  /// Returns the domain that the query applies to.
+  AvailabilityDomain getDomain() const { return domain; }
+
+  /// Returns true if the query's result is determined at compile-time.
+  bool isConstant() const { return kind != ResultKind::Dynamic; }
+
+  /// Returns true if the query was spelled `#unavailable`.
+  bool isUnavailability() const { return unavailable; }
+
+  /// Returns the boolean result of the query if it is known at compile-time, or
+  /// `std::nullopt` otherwise. The returned value accounts for whether the
+  /// query was spelled `#unavailable`.
+  std::optional<bool> getConstantResult() const {
+    switch (kind) {
+    case ResultKind::ConstTrue:
+      return !unavailable;
+    case ResultKind::ConstFalse:
+      return unavailable;
+    case ResultKind::Dynamic:
+      return std::nullopt;
+    }
+  }
+
+  /// Returns the availability range that is the first argument to query
+  /// function.
+  std::optional<AvailabilityRange> getPrimaryRange() const {
+    return primaryRange;
+  }
+
+  /// Returns the version tuple that is the first argument to query function.
+  std::optional<llvm::VersionTuple> getPrimaryArgument() const {
+    if (!primaryRange)
+      return std::nullopt;
+    return primaryRange->getRawMinimumVersion();
+  }
+
+  /// Returns the availability range that is the second argument to query
+  /// function. This represents the `-target-variant` version when compiling a
+  /// zippered library.
+  std::optional<AvailabilityRange> getVariantRange() const {
+    return variantRange;
+  }
+
+  /// Returns the version tuple that is the second argument to query function.
+  /// This represents the `-target-variant` version when compiling a zippered
+  /// library.
+  std::optional<llvm::VersionTuple> getVariantArgument() const {
+    if (!variantRange)
+      return std::nullopt;
+    return variantRange->getRawMinimumVersion();
+  }
+
+  /// Returns the `FuncDecl *` that should be invoked at runtime to evaluate
+  /// the query, and populates `arguments` with the arguments to invoke it with
+  /// (the integer components of the version tuples that are being tested). If
+  /// the query does not have a dynamic result, returns `nullptr`.
+  FuncDecl *
+  getDynamicQueryDeclAndArguments(llvm::SmallVectorImpl<unsigned> &arguments,
+                                  ASTContext &ctx) const;
+};
+
+} // end namespace swift
+
+#endif
diff --git a/include/swift/AST/AvailabilityRange.h b/include/swift/AST/AvailabilityRange.h
index c679ea0b01db8..5580b6bae2c57 100644
--- a/include/swift/AST/AvailabilityRange.h
+++ b/include/swift/AST/AvailabilityRange.h
@@ -21,7 +21,7 @@
 #include "swift/Basic/LLVM.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/Support/VersionTuple.h"
-#include <optional>
+#include "llvm/Support/raw_ostream.h"
 
 namespace swift {
 class ASTContext;
@@ -317,11 +317,20 @@ class AvailabilityRange {
 
   /// Returns a representation of this range as a string for debugging purposes.
   std::string getAsString() const {
-    return "AvailabilityRange(" + getVersionString() + ")";
+    return "AvailabilityRange(" + getVersionDescription() + ")";
   }
 
-  /// Returns a representation of the raw version range as a string for
+  /// Returns a representation of the version range as a string for
   /// debugging purposes.
+  std::string getVersionDescription() const {
+    if (Range.hasLowerEndpoint())
+      return Range.getLowerEndpoint().getAsString();
+    else
+      return Range.isEmpty() ? "never" : "always";
+  }
+
+  /// Returns a string representation of the raw version range. It is an error
+  /// to call this if the range is "always" or "never".
   std::string getVersionString() const {
     ASSERT(Range.hasLowerEndpoint());
     return Range.getLowerEndpoint().getAsString();
@@ -330,4 +339,20 @@ class AvailabilityRange {
 
 } // end namespace swift
 
+namespace llvm {
+
+inline llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
+                                     const swift::VersionRange &range) {
+  os << range.getAsString();
+  return os;
+}
+
+inline llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
+                                     const swift::AvailabilityRange &range) {
+  os << range.getAsString();
+  return os;
+}
+
+} // namespace llvm
+
 #endif
diff --git a/include/swift/AST/AvailabilityScope.h b/include/swift/AST/AvailabilityScope.h
index 210d8289083f6..e56d1260a727f 100644
--- a/include/swift/AST/AvailabilityScope.h
+++ b/include/swift/AST/AvailabilityScope.h
@@ -272,8 +272,11 @@ class AvailabilityScope : public ASTAllocated<AvailabilityScope> {
       AvailabilityDomain Domain, const llvm::VersionTuple &Version) const;
 
   /// Returns the availability version range that was explicitly written in
-  /// source, if applicable. Otherwise, returns null.
-  std::optional<const AvailabilityRange> getExplicitAvailabilityRange() const;
+  /// source for the given domain, if applicable. Otherwise, returns
+  /// `std::nullopt`.
+  std::optional<const AvailabilityRange>
+  getExplicitAvailabilityRange(AvailabilityDomain Domain,
+                               ASTContext &Ctx) const;
 
   /// Returns the source range this scope represents.
   SourceRange getSourceRange() const { return SrcRange; }
diff --git a/include/swift/AST/AvailabilitySpec.h b/include/swift/AST/AvailabilitySpec.h
index b07217a0fa94d..dbb951f2b15f3 100644
--- a/include/swift/AST/AvailabilitySpec.h
+++ b/include/swift/AST/AvailabilitySpec.h
@@ -1,8 +1,8 @@
-//===--- AvailabilitySpec.h - Swift Availability Query ASTs -----*- C++ -*-===//
+//===--- AvailabilitySpec.h - Swift Availability Spec ASTs ------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -20,13 +20,14 @@
 #include "swift/AST/ASTAllocated.h"
 #include "swift/AST/AvailabilityDomain.h"
 #include "swift/AST/Identifier.h"
-#include "swift/AST/PlatformKind.h"
+#include "swift/AST/PlatformKindUtils.h"
 #include "swift/Basic/STLExtras.h"
 #include "swift/Basic/SourceLoc.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Support/VersionTuple.h"
+#include "llvm/Support/raw_ostream.h"
 
 namespace swift {
 class ASTContext;
@@ -241,4 +242,20 @@ class AvailabilityMacroMap {
 
 } // end namespace swift
 
+namespace llvm {
+
+inline llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
+                                     const swift::AvailabilitySpec *spec) {
+  spec->print(os);
+  return os;
+}
+
+inline llvm::raw_ostream &
+operator<<(llvm::raw_ostream &os, const swift::SemanticAvailabilitySpec &spec) {
+  spec.print(os);
+  return os;
+}
+
+} // end namespace llvm
+
 #endif
diff --git a/include/swift/AST/Builtins.def b/include/swift/AST/Builtins.def
index 1d4ad98881ceb..b39972c7be964 100644
--- a/include/swift/AST/Builtins.def
+++ b/include/swift/AST/Builtins.def
@@ -240,6 +240,7 @@ BUILTIN_SIL_OPERATION(LoadRaw, "loadRaw", Special)
 BUILTIN_SIL_OPERATION(LoadInvariant, "loadInvariant", Special)
 
 /// Take has type (Builtin.RawPointer) -> T
+/// where T: ~Copyable & ~Escapable
 BUILTIN_SIL_OPERATION(Take, "take", Special)
 
 /// Destroy has type (T.Type, Builtin.RawPointer) -> ()
@@ -673,9 +674,22 @@ BUILTIN_MISC_OPERATION(ExtractElement, "extractelement", "n", Special)
 /// InsertElement has type (Vector<N, T>, T, Int32) -> Vector<N, T>.
 BUILTIN_MISC_OPERATION(InsertElement, "insertelement", "n", Special)
 
-// Shufflevector has type (VecN<T>, VecN<T>, VecM<Int32>) -> VecM<T>
+/// Select has type either
+///   (VecN<Int1>, VecN<T>, VecN<T>) -> VecN<T>
+/// or
+///   (Int1, T, T) -> T
+/// T must be trivial.
+BUILTIN_MISC_OPERATION(Select, "select", "n", Special)
+
+/// Shufflevector has type (VecN<T>, VecN<T>, VecM<Int32>) -> VecM<T>
 BUILTIN_MISC_OPERATION(ShuffleVector, "shufflevector", "n", Special)
 
+/// Interleave has type (VecN<T>, VecN<T>) -> (VecN<T>, VecN<T>)
+BUILTIN_MISC_OPERATION(Interleave, "interleave", "n", Special)
+
+/// Deinterleave has type (VecN<T>, VecN<T>) -> (VecN<T>, VecN<T>)
+BUILTIN_MISC_OPERATION(Deinterleave, "deinterleave", "n", Special)
+
 /// StaticReport has type (Builtin.Int1, Builtin.Int1, Builtin.RawPointer) -> ()
 BUILTIN_MISC_OPERATION(StaticReport, "staticReport", "", Special)
 
@@ -844,6 +858,10 @@ BUILTIN_MISC_OPERATION_WITH_SILGEN(Alignof, "alignof", "n", Special)
 /// own rules.
 BUILTIN_MISC_OPERATION_WITH_SILGEN(ZeroInitializer, "zeroInitializer", "n", Special)
 
+/// Like `zeroInitializer`, but does not actually initialize the memory.
+/// It only indicates to mandatory passes that the memory is going to be initialized.
+BUILTIN_MISC_OPERATION(PrepareInitialization, "prepareInitialization", "n", Special)
+
 // getCurrentExecutor: () async -> Builtin.Executor?
 //
 // Retrieve the SerialExecutorRef on which the current asynchronous
diff --git a/include/swift/AST/Builtins.h b/include/swift/AST/Builtins.h
index 799fd3514feec..213a61ff50a70 100644
--- a/include/swift/AST/Builtins.h
+++ b/include/swift/AST/Builtins.h
@@ -121,12 +121,13 @@ class BuiltinInfo {
 
 /// The information identifying the llvm intrinsic - its id and types.
 class IntrinsicInfo {
-  mutable llvm::AttributeList Attrs =
-      llvm::DenseMapInfo<llvm::AttributeList>::getEmptyKey();
+  mutable llvm::AttributeSet FnAttrs =
+      llvm::DenseMapInfo<llvm::AttributeSet>::getEmptyKey();
+
 public:
   llvm::Intrinsic::ID ID;
   SmallVector<Type, 4> Types;
-  const llvm::AttributeList &getOrCreateAttributes(ASTContext &Ctx) const;
+  const llvm::AttributeSet &getOrCreateFnAttributes(ASTContext &Ctx) const;
 };
 
 /// Turn a string like "release" into the LLVM enum.
diff --git a/include/swift/AST/CanTypeVisitor.h b/include/swift/AST/CanTypeVisitor.h
index 658f01488ecbf..d0b163630973b 100644
--- a/include/swift/AST/CanTypeVisitor.h
+++ b/include/swift/AST/CanTypeVisitor.h
@@ -70,6 +70,70 @@ class CanTypeVisitor {
 #include "swift/AST/TypeNodes.def"
 };
 
+/// This is a convenience refinement of CanTypeVisitor which forwards the
+/// paired nominal type methods to a common implementation.
+///
+/// The delegation flow is:
+///   {ClassType, BoundGenericClassType} -> AnyClassType -> AnyNominalType -> Type
+///   {EnumType, BoundGenericEnumType} -> AnyEnumType -> AnyNominalType -> Type
+///   {StructType, BoundGenericStructType} -> AnyStructType -> AnyNominalType -> Type
+///   ProtocolType -> AnyNominalType -> Type
+///
+/// The new visitAny*Type methods take the appropriate Decl* as their second
+/// argument.
+template<typename ImplClass, typename RetTy = void, typename... Args>
+class CanTypeVisitor_AnyNominal : public CanTypeVisitor<ImplClass, RetTy, Args...> {
+public:
+  RetTy visitClassType(CanClassType T, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyClassType(T, T->getDecl(), ::std::forward<Args>(args)...);
+  }
+  RetTy visitBoundGenericClassType(CanBoundGenericClassType T, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyClassType(T, T->getDecl(), ::std::forward<Args>(args)...);
+  }
+  RetTy visitAnyClassType(CanType T, ClassDecl *D, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyNominalType(T, D, ::std::forward<Args>(args)...);
+  }
+
+  RetTy visitStructType(CanStructType T, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyStructType(T, T->getDecl(), ::std::forward<Args>(args)...);
+  }
+  RetTy visitBoundGenericStructType(CanBoundGenericStructType T, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyStructType(T, T->getDecl(), ::std::forward<Args>(args)...);
+  }
+  RetTy visitAnyStructType(CanType T, StructDecl *D, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyNominalType(T, D, ::std::forward<Args>(args)...);
+  }
+
+  RetTy visitEnumType(CanEnumType T, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyEnumType(T, T->getDecl(), ::std::forward<Args>(args)...);
+  }
+  RetTy visitBoundGenericEnumType(CanBoundGenericEnumType T, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyEnumType(T, T->getDecl(), ::std::forward<Args>(args)...);
+  }
+  RetTy visitAnyEnumType(CanType T, EnumDecl *D, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyNominalType(T, D, ::std::forward<Args>(args)...);
+  }
+
+  RetTy visitProtocolType(CanProtocolType T, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitAnyNominalType(T, T->getDecl(), ::std::forward<Args>(args)...);
+  }
+
+  RetTy visitAnyNominalType(CanType T, NominalTypeDecl *D, Args... args) {
+    return static_cast<ImplClass*>(this)
+      ->visitType(T, ::std::forward<Args>(args)...);
+  }
+};
+
 } // end namespace swift
   
 #endif
diff --git a/include/swift/AST/CatchNode.h b/include/swift/AST/CatchNode.h
index 67525f13acbeb..f7e05b3513f79 100644
--- a/include/swift/AST/CatchNode.h
+++ b/include/swift/AST/CatchNode.h
@@ -22,12 +22,16 @@
 
 namespace swift {
 
+namespace detail {
+using CatchNodeBase = llvm::PointerUnion<AbstractFunctionDecl *, ClosureExpr *,
+                                         DoCatchStmt *, AnyTryExpr *>;
+} // end namespace detail
+
 /// An AST node that represents a point where a thrown error can be caught and
 /// or rethrown, which includes functions do...catch statements.
-class CatchNode: public llvm::PointerUnion<
-    AbstractFunctionDecl *, ClosureExpr *, DoCatchStmt *, AnyTryExpr *
-  > {
+class CatchNode : public detail::CatchNodeBase {
 public:
+  using Base = detail::CatchNodeBase;
   using PointerUnion::PointerUnion;
 
   /// Determine the thrown error type within the region of this catch node
@@ -62,4 +66,17 @@ SourceLoc extractNearestSourceLoc(CatchNode catchNode);
 
 } // end namespace swift
 
+namespace llvm {
+
+using swift::CatchNode;
+
+/// `isa`, `dyn_cast`, `cast` for `CatchNode`.
+template <typename To>
+struct CastInfo<To, CatchNode> : public CastInfo<To, CatchNode::Base> {};
+template <typename To>
+struct CastInfo<To, const CatchNode>
+    : public CastInfo<To, const CatchNode::Base> {};
+
+} // end namespace llvm
+
 #endif // SWIFT_AST_CATCHNODE_H
diff --git a/include/swift/AST/ClangModuleLoader.h b/include/swift/AST/ClangModuleLoader.h
index 8213540c0a595..8175e797337af 100644
--- a/include/swift/AST/ClangModuleLoader.h
+++ b/include/swift/AST/ClangModuleLoader.h
@@ -216,6 +216,9 @@ class ClangModuleLoader : public ModuleLoader {
                                           DeclContext *newContext,
                                           ClangInheritanceInfo inheritance) = 0;
 
+  /// Returnes the original method if \param decl is a clone from a base class
+  virtual ValueDecl *getOriginalForClonedMember(const ValueDecl *decl) = 0;
+
   /// Emits diagnostics for any declarations named name
   /// whose direct declaration context is a TU.
   virtual void diagnoseTopLevelValue(const DeclName &name) = 0;
@@ -295,6 +298,9 @@ class ClangModuleLoader : public ModuleLoader {
 
   virtual FuncDecl *getDefaultArgGenerator(const clang::ParmVarDecl *param) = 0;
 
+  virtual FuncDecl *
+  getAvailabilityDomainPredicate(const clang::VarDecl *var) = 0;
+
   virtual std::optional<Type>
   importFunctionReturnType(const clang::FunctionDecl *clangDecl,
                            DeclContext *dc) = 0;
diff --git a/include/swift/AST/ClangNode.h b/include/swift/AST/ClangNode.h
index 9891d1915dc8b..062cd51d341ba 100644
--- a/include/swift/AST/ClangNode.h
+++ b/include/swift/AST/ClangNode.h
@@ -14,6 +14,7 @@
 #define SWIFT_CLANGNODE_H
 
 #include "swift/Basic/Debug.h"
+#include "swift/Basic/LLVM.h"
 #include "llvm/ADT/PointerUnion.h"
 
 namespace clang {
@@ -76,16 +77,16 @@ class ClangNode {
   }
 
   const clang::Decl *castAsDecl() const {
-    return Ptr.get<Box<clang::Decl>>().value;
+    return cast<Box<clang::Decl>>(Ptr).value;
   }
   const clang::MacroInfo *castAsMacroInfo() const {
-    return Ptr.get<Box<clang::MacroInfo>>().value;
+    return cast<Box<clang::MacroInfo>>(Ptr).value;
   }
   const clang::ModuleMacro *castAsModuleMacro() const {
-    return Ptr.get<Box<clang::ModuleMacro>>().value;
+    return cast<Box<clang::ModuleMacro>>(Ptr).value;
   }
   const clang::Module *castAsModule() const {
-    return Ptr.get<Box<clang::Module>>().value;
+    return cast<Box<clang::Module>>(Ptr).value;
   }
 
   // Get the MacroInfo for a local definition, one imported from a
diff --git a/include/swift/AST/Concurrency.h b/include/swift/AST/Concurrency.h
index 3d19fa40bbe80..c5e0de233c4b4 100644
--- a/include/swift/AST/Concurrency.h
+++ b/include/swift/AST/Concurrency.h
@@ -19,6 +19,11 @@
 
 namespace swift {
 
+/// Find the imported module that treats the given nominal type as "preconcurrency", or return `nullptr`
+/// if there is no such module.
+ModuleDecl *moduleImportForPreconcurrency(NominalTypeDecl *nominal,
+                                          const DeclContext *fromDC);
+
 /// Determinate the appropriate diagnostic behavior to used when emitting
 /// concurrency diagnostics when referencing the given nominal type from the
 /// given declaration context.
diff --git a/include/swift/AST/Decl.h b/include/swift/AST/Decl.h
index 5a5d40dc56920..04767c21d76e9 100644
--- a/include/swift/AST/Decl.h
+++ b/include/swift/AST/Decl.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -19,6 +19,7 @@
 
 #include "swift/AST/AccessScope.h"
 #include "swift/AST/Attr.h"
+#include "swift/AST/AvailabilityQuery.h"
 #include "swift/AST/AvailabilityRange.h"
 #include "swift/AST/CaptureInfo.h"
 #include "swift/AST/ClangNode.h"
@@ -169,6 +170,7 @@ enum class DescriptiveDeclKind : uint8_t {
   PostfixOperator,
   PrecedenceGroup,
   TypeAlias,
+  GenericTypeAlias,
   GenericTypeParam,
   AssociatedType,
   Type,
@@ -183,7 +185,6 @@ enum class DescriptiveDeclKind : uint8_t {
   GenericClass,
   GenericActor,
   GenericDistributedActor,
-  GenericType,
   Subscript,
   StaticSubscript,
   ClassSubscript,
@@ -213,7 +214,10 @@ enum class DescriptiveDeclKind : uint8_t {
   OpaqueResultType,
   OpaqueVarType,
   Macro,
-  MacroExpansion
+  MacroExpansion,
+  Using,
+  BorrowAccessor,
+  MutateAccessor,
 };
 
 /// Describes which spelling was used in the source for the 'static' or 'class'
@@ -267,6 +271,16 @@ static_assert(uint8_t(SelfAccessKind::LastSelfAccessKind) <
               "Self Access Kind is too small to fit in SelfAccess kind bits. "
               "Please expand ");
 
+enum class UsingSpecifier : uint8_t {
+  MainActor,
+  Nonisolated,
+  LastSpecifier = Nonisolated,
+};
+enum : unsigned {
+  NumUsingSpecifierBits =
+      countBitsUsed(static_cast<unsigned>(UsingSpecifier::LastSpecifier))
+};
+
 /// Diagnostic printing of \c SelfAccessKind.
 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, SelfAccessKind SAK);
 
@@ -310,6 +324,9 @@ struct OverloadSignature {
   /// Whether this is a macro.
   unsigned IsMacro : 1;
 
+  /// Whether this is a generic argument.
+  unsigned IsGenericArg : 1;
+
   /// Whether this signature is part of a protocol extension.
   unsigned InProtocolExtension : 1;
 
@@ -323,8 +340,10 @@ struct OverloadSignature {
   OverloadSignature()
       : UnaryOperator(UnaryOperatorKind::None), IsInstanceMember(false),
         IsVariable(false), IsFunction(false), IsAsyncFunction(false),
-        IsDistributed(false), InProtocolExtension(false),
-        InExtensionOfGenericType(false), HasOpaqueReturnType(false) { }
+        IsDistributed(false), IsEnumElement(false), IsNominal(false),
+        IsTypeAlias(false), IsMacro(false), IsGenericArg(false),
+        InProtocolExtension(false), InExtensionOfGenericType(false),
+        HasOpaqueReturnType(false) { }
 };
 
 /// Determine whether two overload signatures conflict.
@@ -806,8 +825,8 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
     /// Whether this module has enabled strict memory safety checking.
     StrictMemorySafety : 1,
 
-    /// Whether this module has enabled `ExtensibleEnums` feature.
-    ExtensibleEnums : 1
+    /// Whether this module uses deferred code generation in Embedded Swift.
+    DeferredCodeGen : 1
   );
 
   SWIFT_INLINE_BITFIELD(PrecedenceGroupDecl, Decl, 1+2,
@@ -825,6 +844,10 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
     NumPathElements : 8
   );
 
+  SWIFT_INLINE_BITFIELD(UsingDecl, Decl, NumUsingSpecifierBits,
+    Specifier : NumUsingSpecifierBits
+  );
+
   SWIFT_INLINE_BITFIELD(ExtensionDecl, Decl, 4+1,
     /// An encoding of the default and maximum access level for this extension.
     /// The value 4 corresponds to AccessLevel::Public
@@ -1004,7 +1027,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
     if (auto dc = Context.dyn_cast<DeclContext *>())
       return dc->getASTContext();
 
-    return *Context.get<ASTContext *>();
+    return *cast<ASTContext *>(Context);
   }
 
   const DeclAttributes &getAttrs() const {
@@ -1050,6 +1073,14 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
   /// behaviors for it and, if it's an extension, its members.
   bool isObjCImplementation() const;
 
+  /// True if this declaration should never have its implementation made
+  /// available to any client. This overrides cross-module optimization and
+  /// optimizations that might use the implementation, such that the only
+  /// implementation of this function is the one compiled into its owning
+  /// module. Practically speaking, this prohibits serialization of the SIL
+  /// for this definition.
+  bool isNeverEmittedIntoClient() const;
+
   using AuxiliaryDeclCallback = llvm::function_ref<void(Decl *)>;
 
   /// Iterate over the auxiliary declarations for this declaration,
@@ -1098,15 +1129,14 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
   std::optional<llvm::VersionTuple>
   getIntroducedOSVersion(PlatformKind Kind) const;
 
-  /// Returns the OS version in which the decl became ABI as specified by the
-  /// `@backDeployed` attribute.
-  std::optional<llvm::VersionTuple>
-  getBackDeployedBeforeOSVersion(ASTContext &Ctx,
-                                 bool forTargetVariant = false) const;
+  /// Returns the active `@backDeployed` attribute and the `AvailabilityRange`
+  /// in which the decl is available as ABI.
+  std::optional<std::pair<const BackDeployedAttr *, AvailabilityRange>>
+  getBackDeployedAttrAndRange(ASTContext &Ctx,
+                              bool forTargetVariant = false) const;
 
-  /// Returns true if the decl has an active `@backDeployed` attribute for the
-  /// given context.
-  bool isBackDeployed(ASTContext &Ctx) const;
+  /// Returns true if the decl has a valid and active `@backDeployed` attribute.
+  bool isBackDeployed() const;
 
   /// Returns the starting location of the entire declaration.
   SourceLoc getStartLoc() const { return getSourceRange().Start; }
@@ -1149,6 +1179,10 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
   /// constructed from a serialized module.
   bool isInMacroExpansionInContext() const;
 
+  /// Whether this declaration is within a macro expansion relative to
+  /// its decl context, and the macro was attached to a node imported from clang.
+  bool isInMacroExpansionFromClangHeader() const;
+
   /// Returns the appropriate kind of entry point to generate for this class,
   /// based on its attributes.
   ///
@@ -1443,6 +1477,27 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
   std::optional<SemanticAvailableAttr>
   getAvailableAttrForPlatformIntroduction(bool checkExtension = true) const;
 
+  /// Returns true if `decl` has any active `@available` attribute attached to
+  /// it.
+  bool hasAnyActiveAvailableAttr() const {
+    return hasAnyMatchingActiveAvailableAttr(
+        [](SemanticAvailableAttr attr) -> bool { return true; });
+  }
+
+  /// Returns true if `predicate` returns true for any active availability
+  /// attribute attached to `decl`. The predicate function should accept a
+  /// `SemanticAvailableAttr`.
+  template <typename F>
+  bool hasAnyMatchingActiveAvailableAttr(F predicate) const {
+    auto &ctx = getASTContext();
+    auto decl = getAbstractSyntaxDeclForAttributes();
+    for (auto attr : decl->getSemanticAvailableAttrs()) {
+      if (attr.isActive(ctx) && predicate(attr))
+        return true;
+    }
+    return false;
+  }
+
   /// Returns true if the declaration is deprecated at the current deployment
   /// target.
   bool isDeprecated() const { return getDeprecatedAttr().has_value(); }
@@ -1500,6 +1555,10 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
   /// compatibility mode.
   bool requiresUnavailableDeclABICompatibilityStubs() const;
 
+  /// Returns the decl that should be considered the parent decl when looking
+  /// for inherited availability annotations.
+  const Decl *parentDeclForAvailability() const;
+
   // List the SPI groups declared with @_spi or inherited by this decl.
   //
   // SPI groups are inherited from the parent contexts only if the local decl
@@ -1718,8 +1777,8 @@ class ImportDecl final : public Decl,
   ///          path will include 'Foo'. This return value is always owned by \c ImportDecl
   ///          (which is owned by the AST context), so it can be persisted.
   ImportPath getImportPath() const {
-    return ImportPath({ getTrailingObjects<ImportPath::Element>(),
-                        static_cast<size_t>(Bits.ImportDecl.NumPathElements) });
+    return ImportPath(getTrailingObjects(
+        static_cast<size_t>(Bits.ImportDecl.NumPathElements)));
   }
 
   /// Retrieves the import path, replacing any module aliases with real names.
@@ -1996,6 +2055,7 @@ class ExtensionDecl final : public GenericContext, public Decl,
   std::pair<LazyMemberLoader *, uint64_t> takeConformanceLoaderSlow();
 
   friend class ExtendedNominalRequest;
+  friend class BindExtensionsRequest;
   friend class Decl;
 public:
   using Decl::getASTContext;
@@ -2033,14 +2093,16 @@ class ExtensionDecl final : public GenericContext, public Decl,
   Type getExtendedType() const;
 
   /// Retrieve the nominal type declaration that is being extended.
-  /// Will  trip an assertion if the declaration has not already been computed.
+  /// Will trip an assertion if the declaration has not already been computed.
   /// In order to fail fast when type checking work is attempted
   /// before extension binding has taken place.
-
   NominalTypeDecl *getExtendedNominal() const;
 
-  /// Compute the nominal type declaration that is being extended.
-  NominalTypeDecl *computeExtendedNominal() const;
+  /// Compute the nominal type declaration that is being extended. The result
+  /// is not cached, this should only be invoked by extension binding itself.
+  /// FIXME: Make this private once lldb has been migrated off it.
+  NominalTypeDecl *computeExtendedNominal(
+      bool excludeMacroExpansions=false) const;
 
   /// \c hasBeenBound means nothing if this extension can never been bound
   /// because it is not at the top level.
@@ -2110,7 +2172,10 @@ class ExtensionDecl final : public GenericContext, public Decl,
 
   /// Determine whether this extension context is in the same defining module as
   /// the original nominal type context.
-  bool isInSameDefiningModule() const;
+  ///
+  /// \param RespectOriginallyDefinedIn Whether to respect
+  /// \c @_originallyDefinedIn attributes or the actual location of the decls.
+  bool isInSameDefiningModule(bool RespectOriginallyDefinedIn = true) const;
 
   /// Determine whether this extension is equivalent to one that requires at
   /// at least some constraints to be written in the source.
@@ -2287,6 +2352,7 @@ class PatternBindingEntry {
   // Flags::Checked.
   friend class PatternBindingEntryRequest;
   friend class PatternBindingCheckedAndContextualizedInitRequest;
+  friend class PatternBindingCaptureInfoRequest;
 
   bool isFullyValidated() const {
     return InitContextAndFlags.getInt().contains(
@@ -2435,8 +2501,20 @@ class PatternBindingEntry {
   /// from the source range.
   SourceRange getSourceRange(bool omitAccessors = false) const;
 
-  CaptureInfo getCaptureInfo() const { return Captures; }
-  void setCaptureInfo(CaptureInfo captures) { Captures = captures; }
+  /// Retrieve the computed capture info, or \c nullopt if it hasn't been
+  /// computed yet.
+  std::optional<CaptureInfo> getCachedCaptureInfo() const {
+    if (!Captures.hasBeenComputed())
+      return std::nullopt;
+
+    return Captures;
+  }
+
+  void setCaptureInfo(CaptureInfo captures) {
+    ASSERT(!Captures.hasBeenComputed());
+    ASSERT(captures.hasBeenComputed());
+    Captures = captures;
+  }
 
 private:
   SourceLoc getLastAccessorEndLoc() const;
@@ -2460,6 +2538,7 @@ class PatternBindingDecl final : public Decl,
   friend class Decl;
   friend class PatternBindingEntryRequest;
   friend class PatternBindingCheckedAndContextualizedInitRequest;
+  friend class PatternBindingCaptureInfoRequest;
 
   SourceLoc StaticLoc; ///< Location of the 'static/class' keyword, if present.
   SourceLoc VarLoc;    ///< Location of the 'var' keyword.
@@ -2503,9 +2582,7 @@ class PatternBindingDecl final : public Decl,
                                                Pattern *Pat, Expr *E,
                                                DeclContext *Parent);
 
-  SourceLoc getStartLoc() const {
-    return StaticLoc.isValid() ? StaticLoc : VarLoc;
-  }
+  SourceLoc getStartLoc() const;
   SourceRange getSourceRange() const;
 
   unsigned getNumPatternEntries() const {
@@ -2639,13 +2716,9 @@ class PatternBindingDecl final : public Decl,
     getMutablePatternList()[i].setInitContext(init);
   }
 
-  CaptureInfo getCaptureInfo(unsigned i) const {
-    return getPatternList()[i].getCaptureInfo();
-  }
-
-  void setCaptureInfo(unsigned i, CaptureInfo captures) {
-    getMutablePatternList()[i].setCaptureInfo(captures);
-  }
+  /// Retrieve the capture info for the initializer at the given index,
+  /// computing if needed.
+  CaptureInfo getCaptureInfo(unsigned i) const;
 
   /// Given that this PBD is the parent pattern for the specified VarDecl,
   /// return the entry of the VarDecl in our PatternList.  For example, in:
@@ -2751,7 +2824,7 @@ class PatternBindingDecl final : public Decl,
 private:
   MutableArrayRef<PatternBindingEntry> getMutablePatternList() {
     // Pattern entries are tail allocated.
-    return {getTrailingObjects<PatternBindingEntry>(), getNumPatternEntries()};
+    return getTrailingObjects(getNumPatternEntries());
   }
 };
   
@@ -2851,6 +2924,10 @@ class ValueDecl : public Decl {
     /// a null pointer.
     unsigned noOpaqueResultType : 1;
 
+    /// Whether the ClangUSRGenerationRequest request was evaluated and produced
+    /// a std::nullopt.
+    unsigned noClangUSR : 1;
+
     /// Whether the "isFinal" bit has been computed yet.
     unsigned isFinalComputed : 1;
 
@@ -2867,6 +2944,10 @@ class ValueDecl : public Decl {
 
     /// Whether we've evaluated the ApplyAccessNoteRequest.
     unsigned accessNoteApplied : 1;
+
+    /// Whether the AvailabilityDomainForDeclRequest request was evaluated and
+    /// yielded no availability domain.
+    unsigned noAvailabilityDomain : 1;
   } LazySemanticInfo = { };
 
   friend class DynamicallyReplacedDeclRequest;
@@ -2880,6 +2961,8 @@ class ValueDecl : public Decl {
   friend class ActorIsolationRequest;
   friend class OpaqueResultTypeRequest;
   friend class ApplyAccessNoteRequest;
+  friend class AvailabilityDomainForDeclRequest;
+  friend class ClangUSRGenerationRequest;
 
   friend class Decl;
   SourceLoc getLocFromSource() const { return NameLoc; }
@@ -3011,6 +3094,10 @@ class ValueDecl : public Decl {
   /// \c \@usableFromInline, \c \@inlinalbe, and \c \@_alwaysEmitIntoClient
   bool isUsableFromInline() const;
 
+  // Returns \c true if this value decl is marked with an attribute that implies
+  // \c \@inlinable semantics: either \c \@inlinable or \c \@inline(always)
+  bool hasAttributeWithInlinableSemantics() const;
+
   /// Returns \c true if this declaration is *not* intended to be used directly
   /// by application developers despite the visibility.
   bool shouldHideFromEditor() const;
@@ -3206,6 +3293,9 @@ class ValueDecl : public Decl {
   /// `AbstractStorageDecl`, returns `false`.
   bool isAsync() const;
 
+  /// Returns whether this function represents a defer body.
+  bool isDeferBody() const;
+
 private:
   bool isObjCDynamic() const {
     return isObjC() && isDynamic();
@@ -3590,10 +3680,7 @@ class OpaqueTypeDecl final :
   /// Retrieve the buffer containing the opaque return type
   /// representations that correspond to the opaque generic parameters.
   ArrayRef<TypeRepr *> getOpaqueReturnTypeReprs() const {
-    return {
-      getTrailingObjects<TypeRepr *>(),
-      getNumOpaqueReturnTypeReprs()
-    };
+    return getTrailingObjects(getNumOpaqueReturnTypeReprs());
   }
 
   /// Should the underlying type be visible to clients outside of the module?
@@ -3601,7 +3688,8 @@ class OpaqueTypeDecl final :
 
   /// The substitutions that map the generic parameters of the opaque type to
   /// the unique underlying types, when that information is known.
-  std::optional<SubstitutionMap> getUniqueUnderlyingTypeSubstitutions() const;
+  std::optional<SubstitutionMap> getUniqueUnderlyingTypeSubstitutions(
+      bool typeCheckFunctionBodies=true) const;
 
   void setUniqueUnderlyingTypeSubstitutions(SubstitutionMap subs) {
     assert(!UniqueUnderlyingType.has_value() && "resetting underlying type?!");
@@ -3640,40 +3728,36 @@ class OpaqueTypeDecl final :
     return false;
   }
 
-  using AvailabilityCondition = std::pair<VersionRange, bool>;
-
   class ConditionallyAvailableSubstitutions final
-      : private llvm::TrailingObjects<
-            ConditionallyAvailableSubstitutions,
-            AvailabilityCondition> {
+      : private llvm::TrailingObjects<ConditionallyAvailableSubstitutions,
+                                      AvailabilityQuery> {
     friend TrailingObjects;
 
-    unsigned NumAvailabilityConditions;
+    unsigned NumAvailabilityQueries;
 
     SubstitutionMap Substitutions;
 
     /// A type with limited availability described by the provided set
     /// of availability conditions (with `and` relationship).
     ConditionallyAvailableSubstitutions(
-        ArrayRef<AvailabilityCondition> availabilityContext,
+        ArrayRef<AvailabilityQuery> availabilityQueries,
         SubstitutionMap substitutions)
-        : NumAvailabilityConditions(availabilityContext.size()),
+        : NumAvailabilityQueries(availabilityQueries.size()),
           Substitutions(substitutions) {
-      assert(!availabilityContext.empty());
-      std::uninitialized_copy(availabilityContext.begin(),
-                              availabilityContext.end(),
-                              getTrailingObjects<AvailabilityCondition>());
+      assert(!availabilityQueries.empty());
+      std::uninitialized_copy(availabilityQueries.begin(),
+                              availabilityQueries.end(), getTrailingObjects());
     }
 
   public:
-    ArrayRef<AvailabilityCondition> getAvailability() const {
-      return {getTrailingObjects<AvailabilityCondition>(), NumAvailabilityConditions};
+    ArrayRef<AvailabilityQuery> getAvailabilityQueries() const {
+      return getTrailingObjects(NumAvailabilityQueries);
     }
 
     SubstitutionMap getSubstitutions() const { return Substitutions; }
 
     static ConditionallyAvailableSubstitutions *
-    get(ASTContext &ctx, ArrayRef<AvailabilityCondition> availabilityContext,
+    get(ASTContext &ctx, ArrayRef<AvailabilityQuery> availabilityContext,
         SubstitutionMap substitutions);
   };
 };
@@ -4819,6 +4903,16 @@ class EnumDecl final : public NominalTypeDecl {
     return getAttrs().hasAttribute<IndirectAttr>();
   }
 
+  /// True if the enum is marked with `@c`.
+  bool isCDeclEnum() const {
+    return getAttrs().hasAttribute<CDeclAttr>();
+  }
+
+  /// True if the enum is marked with `@c` or `@objc`.
+  bool isCCompatibleEnum() const {
+    return isCDeclEnum() || isObjC();
+  }
+
   /// True if the enum can be exhaustively switched within \p useDC.
   ///
   /// Note that this property is \e not necessarily true for all children of
@@ -5851,7 +5945,7 @@ class AbstractStorageDecl : public ValueDecl {
     inline AccessorDecl *getAccessor(AccessorKind kind) const;
 
     ArrayRef<AccessorDecl *> getAllAccessors() const {
-      return { getTrailingObjects<AccessorDecl*>(), NumAccessors };
+      return getTrailingObjects(NumAccessors);
     }
 
     void addOpaqueAccessor(AccessorDecl *accessor);
@@ -5860,7 +5954,7 @@ class AbstractStorageDecl : public ValueDecl {
 
   private:
     MutableArrayRef<AccessorDecl *> getAccessorsBuffer() {
-      return { getTrailingObjects<AccessorDecl*>(), NumAccessors };
+      return getTrailingObjects(NumAccessors);
     }
 
     bool registerAccessor(AccessorDecl *accessor, AccessorIndex index);
@@ -6163,7 +6257,7 @@ class AbstractStorageDecl : public ValueDecl {
   bool requiresOpaqueRead2Coroutine() const;
 
   /// Does this storage require a 'set' accessor in its opaque-accessors set?
-  bool requiresOpaqueSetter() const { return supportsMutation(); }
+  bool requiresOpaqueSetter() const;
 
   /// Does this storage require a '_modify' accessor in its opaque-accessors
   /// set?
@@ -6232,10 +6326,16 @@ class AbstractStorageDecl : public ValueDecl {
                               bool forConformance=false) const;
 
   /// Determine how this storage declaration should actually be accessed.
-  AccessStrategy getAccessStrategy(AccessSemantics semantics,
-                                   AccessKind accessKind, ModuleDecl *module,
-                                   ResilienceExpansion expansion,
-                                   bool useOldABI) const;
+  AccessStrategy getAccessStrategy(
+      AccessSemantics semantics, AccessKind accessKind, ModuleDecl *module,
+      ResilienceExpansion expansion,
+      std::optional<std::pair<SourceRange, const DeclContext *>> location,
+      bool useOldABI) const;
+
+  /// Whether access is via physical storage.
+  bool isAccessedViaPhysicalStorage(AccessSemantics semantics,
+                                    AccessKind accessKind, ModuleDecl *module,
+                                    ResilienceExpansion expansion) const;
 
   /// Do we need to use resilient access patterns outside of this
   /// property's resilience domain?
@@ -6256,9 +6356,12 @@ class AbstractStorageDecl : public ValueDecl {
   /// Otherwise, its override must be referenced.
   bool isValidKeyPathComponent() const;
 
-  /// True if the storage exports a property descriptor for key paths in
-  /// other modules.
-  bool exportsPropertyDescriptor() const;
+  /// If the storage exports a property descriptor for key paths in other
+  /// modules, this returns the generic signature in which its member methods
+  /// are emitted. If the storage does not export a property descriptor,
+  /// returns `std::nullopt`.
+  std::optional<GenericSignature>
+  getPropertyDescriptorGenericSignature() const;
 
   /// True if any of the accessors to the storage is private or fileprivate.
   bool hasPrivateAccessor() const;
@@ -6895,6 +6998,9 @@ class ParamDecl : public VarDecl {
 
     /// Whether or not this parameter is 'sending'.
     IsSending = 1 << 4,
+
+    /// Whether or not this parameter is isolated to a caller.
+    IsCallerIsolated = 1 << 5,
   };
 
   /// The type repr and 3 bits used for flags.
@@ -6972,6 +7078,10 @@ class ParamDecl : public VarDecl {
   /// Create a an identical copy of this ParamDecl.
   static ParamDecl *clone(const ASTContext &Ctx, ParamDecl *PD);
 
+  static ParamDecl *cloneAccessor(const ASTContext &Ctx,
+                                  ParamDecl const *subscriptParam,
+                                  DeclContext *Parent);
+
   static ParamDecl *
   createImplicit(ASTContext &Context, SourceLoc specifierLoc,
                  SourceLoc argumentNameLoc, Identifier argumentName,
@@ -6991,6 +7101,14 @@ class ParamDecl : public VarDecl {
       Identifier parameterName, Expr *defaultValue,
       DefaultArgumentInitializer *defaultValueInitContext, DeclContext *dc);
 
+  SourceLoc getLocFromSource() const {
+    // If we have a name loc, use it, otherwise fallback to the start loc for
+    // e.g enum elements without parameter names.
+    if (auto nameLoc = getNameLoc())
+      return nameLoc;
+    return getStartLoc();
+  }
+
   /// Retrieve the argument (API) name for this function parameter.
   Identifier getArgumentName() const {
     return ArgumentNameAndFlags.getPointer();
@@ -7183,6 +7301,18 @@ class ParamDecl : public VarDecl {
       removeFlag(Flag::IsSending);
   }
 
+  /// Whether or not this parameter is marked with 'nonisolated(nonsending)'.
+  bool isCallerIsolated() const {
+    return getOptions().contains(Flag::IsCallerIsolated);
+  }
+
+  void setCallerIsolated(bool value = true) {
+    if (value)
+      addFlag(Flag::IsCallerIsolated);
+    else
+      removeFlag(Flag::IsCallerIsolated);
+  }
+
   /// Whether or not this parameter is marked with '@_addressable'.
   bool isAddressable() const {
     return getOptions().contains(Flag::IsAddressable);
@@ -8106,6 +8236,11 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
   /// instance method.
   bool isObjCInstanceMethod() const;
 
+  /// Get the foreign language targeted by a @c-style attribute, if any.
+  /// Used to abstract away the change in meaning of @c vs @_cdecl while
+  /// formalizing the attribute.
+  std::optional<ForeignLanguage> getCDeclKind() const;
+
   /// Determine whether the name of an argument is an API name by default
   /// depending on the function context.
   bool argumentNameIsAPIByDefault() const;
@@ -8139,8 +8274,6 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
     return cast_or_null<AbstractFunctionDecl>(ValueDecl::getOverriddenDecl());
   }
 
-  std::optional<ExecutionKind> getExecutionBehavior() const;
-
   /// Whether the declaration is later overridden in the module
   ///
   /// Overrides are resolved during type checking; only query this field after
@@ -8198,10 +8331,6 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
   /// Asserts if not in type context.
   Type getMethodInterfaceType() const;
 
-  /// Tests if this is a function returning a DynamicSelfType, or a
-  /// constructor.
-  bool hasDynamicSelfResult() const;
-
   /// The async function marked as the alternative to this function, if any.
   AbstractFunctionDecl *getAsyncAlternative() const;
 
@@ -8373,9 +8502,8 @@ class FuncDecl : public AbstractFunctionDecl {
   SourceLoc getStaticLoc() const { return StaticLoc; }
   SourceLoc getFuncLoc() const { return FuncLoc; }
 
-  SourceLoc getStartLoc() const {
-    return StaticLoc.isValid() ? StaticLoc : FuncLoc;
-  }
+  SourceLoc getStartLoc() const;
+  SourceLoc getEndLoc() const;
   SourceRange getSourceRange() const;
 
   TypeRepr *getResultTypeRepr() const { return FnRetType.getTypeRepr(); }
@@ -8569,7 +8697,7 @@ class AccessorDecl final : public FuncDecl {
     switch (getAccessorKind()) {
 #define OBSERVING_ACCESSOR(ID, KEYWORD) \
     case AccessorKind::ID: return true;
-#define ACCESSOR(ID) \
+#define ACCESSOR(ID, KEYWORD)                                                  \
     case AccessorKind::ID: return false;
 #include "swift/AST/AccessorKinds.def"
     }
@@ -8592,7 +8720,7 @@ class AccessorDecl final : public FuncDecl {
     switch (getAccessorKind()) {
 #define COROUTINE_ACCESSOR(ID, KEYWORD) \
     case AccessorKind::ID: return true;
-#define ACCESSOR(ID) \
+#define ACCESSOR(ID, KEYWORD)                                                  \
     case AccessorKind::ID: return false;
 #include "swift/AST/AccessorKinds.def"
     }
@@ -8608,6 +8736,13 @@ class AccessorDecl final : public FuncDecl {
   /// an explicit parameter in its parameter list.
   bool isSimpleDidSet() const;
 
+  bool isBorrowAccessor() const {
+    return getAccessorKind() == AccessorKind::Borrow;
+  }
+  bool isMutateAccessor() const {
+    return getAccessorKind() == AccessorKind::Mutate;
+  }
+
   void setIsTransparent(bool transparent) {
     Bits.AccessorDecl.IsTransparent = transparent;
     Bits.AccessorDecl.IsTransparentComputed = 1;
@@ -8672,7 +8807,7 @@ class EnumCaseDecl final : public Decl,
   {
     Bits.EnumCaseDecl.NumElements = Elements.size();
     std::uninitialized_copy(Elements.begin(), Elements.end(),
-                            getTrailingObjects<EnumElementDecl *>());
+                            getTrailingObjects());
   }
   SourceLoc getLocFromSource() const { return CaseLoc; }
 
@@ -8683,8 +8818,8 @@ class EnumCaseDecl final : public Decl,
   
   /// Get the list of elements declared in this case.
   ArrayRef<EnumElementDecl *> getElements() const {
-    return {getTrailingObjects<EnumElementDecl *>(),
-            static_cast<size_t>(Bits.EnumCaseDecl.NumElements)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.EnumCaseDecl.NumElements));
   }
   SourceRange getSourceRange() const;
 
@@ -8719,7 +8854,8 @@ class EnumCaseDecl final : public Decl,
 /// EnumCaseDecl.
 class EnumElementDecl : public DeclContext, public ValueDecl {
   friend class EnumRawValuesRequest;
-  
+  friend class LifetimeDependenceInfoRequest;
+
   /// This is the type specified with the enum element, for
   /// example 'Int' in 'case Y(Int)'.  This is null if there is no type
   /// associated with this element, as in 'case Z' or in all elements of enum
@@ -8731,6 +8867,11 @@ class EnumElementDecl : public DeclContext, public ValueDecl {
   /// The raw value literal for the enum element, or null.
   LiteralExpr *RawValueExpr;
 
+protected:
+  struct {
+    unsigned NoLifetimeDependenceInfo : 1;
+  } LazySemanticInfo = {};
+
 public:
   EnumElementDecl(SourceLoc IdentifierLoc, DeclName Name,
                   ParameterList *Params,
@@ -9693,6 +9834,34 @@ class MacroExpansionDecl : public Decl, public FreestandingMacroExpansion {
   }
 };
 
+/// UsingDecl - This represents a single `using` declaration, e.g.:
+///   using @MainActor
+class UsingDecl : public Decl {
+  friend class Decl;
+
+private:
+  SourceLoc UsingLoc, SpecifierLoc;
+
+  UsingDecl(SourceLoc usingLoc, SourceLoc specifierLoc,
+            UsingSpecifier specifier, DeclContext *parent);
+
+public:
+  UsingSpecifier getSpecifier() const {
+    return static_cast<UsingSpecifier>(Bits.UsingDecl.Specifier);
+  }
+
+  std::string getSpecifierName() const;
+
+  SourceLoc getLocFromSource() const { return UsingLoc; }
+  SourceRange getSourceRange() const { return {UsingLoc, SpecifierLoc}; }
+
+  static UsingDecl *create(ASTContext &ctx, SourceLoc usingLoc,
+                           SourceLoc specifierLoc, UsingSpecifier specifier,
+                           DeclContext *parent);
+
+  static bool classof(const Decl *D) { return D->getKind() == DeclKind::Using; }
+};
+
 inline void
 AbstractStorageDecl::overwriteSetterAccess(AccessLevel accessLevel) {
   Accessors.setInt(accessLevel);
diff --git a/include/swift/AST/DeclAttr.def b/include/swift/AST/DeclAttr.def
index 654d9cf221688..632cdebe58d95 100644
--- a/include/swift/AST/DeclAttr.def
+++ b/include/swift/AST/DeclAttr.def
@@ -143,7 +143,7 @@ SIMPLE_DECL_ATTR(NSManaged, NSManaged,
 
 CONTEXTUAL_SIMPLE_DECL_ATTR(lazy, Lazy,
   OnVar,
-  DeclModifier | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  DeclModifier | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | UnconstrainedInABIAttr,
   16)
 
 SIMPLE_DECL_ATTR(LLDBDebuggerFunction, LLDBDebuggerFunction,
@@ -163,7 +163,7 @@ SIMPLE_DECL_ATTR(unsafe_no_objc_tagged_pointer, UnsafeNoObjCTaggedPointer,
 
 DECL_ATTR(inline, Inline,
   OnVar | OnSubscript | OnAbstractFunction,
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   20)
 
 DECL_ATTR(_semantics, Semantics,
@@ -193,7 +193,7 @@ CONTEXTUAL_SIMPLE_DECL_ATTR(postfix, Postfix,
 
 SIMPLE_DECL_ATTR(_transparent, Transparent,
   OnFunc | OnAccessor | OnConstructor | OnVar | OnDestructor,
-  UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   26)
 
 SIMPLE_DECL_ATTR(requires_stored_property_inits, RequiresStoredPropertyInits,
@@ -201,7 +201,11 @@ SIMPLE_DECL_ATTR(requires_stored_property_inits, RequiresStoredPropertyInits,
   ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | UnreachableInABIAttr,
   27)
 
-// Unused '28'
+SIMPLE_DECL_ATTR(_neverEmitIntoClient, NeverEmitIntoClient,
+  OnVar | OnSubscript | OnAbstractFunction,
+  UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
+  28)
+
 // Unused '29'
 
 SIMPLE_DECL_ATTR(nonobjc, NonObjC,
@@ -216,7 +220,7 @@ SIMPLE_DECL_ATTR(_fixed_layout, FixedLayout,
 
 SIMPLE_DECL_ATTR(inlinable, Inlinable,
   OnVar | OnSubscript | OnAbstractFunction,
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   32)
 
 DECL_ATTR(_specialize, Specialize,
@@ -364,10 +368,11 @@ SIMPLE_DECL_ATTR(_show_in_interface, ShowInInterface,
   UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | UnreachableInABIAttr,
   62)
 
-DECL_ATTR(_cdecl, CDecl,
-  OnFunc | OnAccessor,
+DECL_ATTR(c, CDecl,
+  OnFunc | OnAccessor | OnEnum,
   LongAttribute | UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   63)
+DECL_ATTR_ALIAS(_cdecl, CDecl)
 
 SIMPLE_DECL_ATTR(usableFromInline, UsableFromInline,
   OnAbstractFunction | OnVar | OnSubscript | OnNominalType | OnTypeAlias,
@@ -455,7 +460,7 @@ DECL_ATTR(_dynamicReplacement, DynamicReplacement,
 
 SIMPLE_DECL_ATTR(_borrowed, Borrowed,
   OnVar | OnSubscript,
-  UserInaccessible | NotSerialized | ABIBreakingToAdd | ABIBreakingToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  UserInaccessible | NotSerialized | ABIBreakingToAdd | ABIBreakingToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   81)
 
 DECL_ATTR(_private, PrivateImport,
@@ -465,7 +470,7 @@ DECL_ATTR(_private, PrivateImport,
 
 SIMPLE_DECL_ATTR(_alwaysEmitIntoClient, AlwaysEmitIntoClient,
   OnVar | OnSubscript | OnAbstractFunction,
-  UserInaccessible | ABIBreakingToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  UserInaccessible | ABIBreakingToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   83)
 
 SIMPLE_DECL_ATTR(_implementationOnly, ImplementationOnly,
@@ -619,9 +624,10 @@ SIMPLE_DECL_ATTR(_implicitSelfCapture, ImplicitSelfCapture,
   UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIBreakingToRemove | ForbiddenInABIAttr,
   115)
 
-SIMPLE_DECL_ATTR(_inheritActorContext, InheritActorContext,
+DECL_ATTR(_inheritActorContext, InheritActorContext,
   OnParam,
-  UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIBreakingToAdd | APIBreakingToRemove | ForbiddenInABIAttr,
+  // since the _inheritActorContext(always) forces an actor capture, it changes ABI of the closure this applies to
+  UserInaccessible | ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove | UnconstrainedInABIAttr,
   116)
 
 SIMPLE_DECL_ATTR(_eagerMove, EagerMove,
@@ -809,7 +815,10 @@ SIMPLE_DECL_ATTR(_noObjCBridging, NoObjCBridging,
   UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   155)
 
-// Unused '156': Used to be `_distributedThunkTarget` but completed implementation in Swift 6.0 does not need it after all
+SIMPLE_DECL_ATTR(_manualOwnership, ManualOwnership,
+  OnAbstractFunction | OnSubscript,
+  UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
+  156)
 
 DECL_ATTR(_allowFeatureSuppression, AllowFeatureSuppression,
   OnAnyDecl,
@@ -832,7 +841,7 @@ SIMPLE_DECL_ATTR(sensitive, Sensitive,
   159)
 
 SIMPLE_DECL_ATTR(unsafe, Unsafe,
-  OnAbstractFunction | OnSubscript | OnVar | OnMacro | OnNominalType | OnExtension | OnTypeAlias | OnEnumElement,
+  OnAbstractFunction | OnSubscript | OnVar | OnMacro | OnNominalType | OnExtension | OnTypeAlias | OnEnumElement | OnImport,
   UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   160)
 
@@ -840,6 +849,7 @@ DECL_ATTR(lifetime, Lifetime,
   OnAccessor | OnConstructor | OnFunc | OnSubscript,
   LongAttribute | ABIBreakingToAdd | ABIStableToRemove | APIBreakingToAdd | APIStableToRemove | AllowMultipleAttributes | EquivalentInABIAttr,
   161)
+DECL_ATTR_ALIAS(_lifetime, Lifetime)
 
 SIMPLE_DECL_ATTR(_addressableSelf, AddressableSelf,
   OnAccessor | OnConstructor | OnFunc | OnSubscript,
@@ -860,13 +870,8 @@ DECL_ATTR(abi, ABI,
   OnConstructor | OnFunc | OnSubscript | OnVar,
   LongAttribute | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   165)
-DECL_ATTR_FEATURE_REQUIREMENT(ABI, ABIAttribute)
 
-DECL_ATTR(execution, Execution,
-  OnFunc | OnConstructor | OnSubscript | OnVar,
-  ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove | UnconstrainedInABIAttr,
-  166)
-DECL_ATTR_FEATURE_REQUIREMENT(Execution, ExecutionAttribute)
+// Unused '166': Used to be `@execution(caller | concurrent)` replaced with `@concurrent` and `nonisolated(nonsending)`
 
 SIMPLE_DECL_ATTR(const, ConstVal,
   OnParam | OnVar | OnFunc,
@@ -879,7 +884,30 @@ SIMPLE_DECL_ATTR(constInitialized, ConstInitialized,
   168)
 DECL_ATTR_FEATURE_REQUIREMENT(ConstInitialized, CompileTimeValues)
 
-LAST_DECL_ATTR(ConstInitialized)
+DECL_ATTR(nonexhaustive, Nonexhaustive,
+  OnEnum,
+  ABIStableToAdd | ABIStableToRemove | APIBreakingToAdd | APIStableToRemove | ForbiddenInABIAttr,
+  169)
+DECL_ATTR_FEATURE_REQUIREMENT(Nonexhaustive, NonexhaustiveAttribute)
+
+SIMPLE_DECL_ATTR(concurrent, Concurrent,
+  OnFunc | OnConstructor | OnSubscript | OnVar,
+  ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove | UnconstrainedInABIAttr,
+  170)
+
+// Unused '171': Used to be `@preEnumExtensibility`
+
+DECL_ATTR(specialized, Specialized,
+  OnConstructor | OnFunc | OnAccessor,
+  AllowMultipleAttributes | LongAttribute | UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
+  172)
+
+SIMPLE_DECL_ATTR(_unsafeSelfDependentResult, UnsafeSelfDependentResult,
+  OnAccessor,
+  UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIBreakingToAdd | APIBreakingToRemove | EquivalentInABIAttr,
+  173)
+
+LAST_DECL_ATTR(UnsafeSelfDependentResult)
 
 #undef DECL_ATTR_ALIAS
 #undef CONTEXTUAL_DECL_ATTR_ALIAS
diff --git a/include/swift/AST/DeclContext.h b/include/swift/AST/DeclContext.h
index 72d7192cfc280..b064f05cfd95d 100644
--- a/include/swift/AST/DeclContext.h
+++ b/include/swift/AST/DeclContext.h
@@ -114,21 +114,20 @@ enum class DeclContextKind : unsigned {
 /// Describes the kind of a particular conformance.
 ///
 /// The following code involves conformances of the three different kinds:
-/// \code
-/// protocol P { }
-/// protocol P2 : P { }
 ///
-/// class Super : P2 { }
-/// class Sub : Super { }
-/// \endcode
+///     protocol P { }
+///     protocol P2 : P { }
 ///
-/// \c Super conforms to \c P2 via an explicit conformance,
+///     class Super : P2 { }
+///     class Sub : Super { }
+///
+/// `Super` conforms to `P2` via an explicit conformance,
 /// specified on the class declaration itself.
 ///
-/// \c Super conforms to \c P via an implied conformance, whose
-/// origin is the explicit conformance to \c P2.
+/// `Super` conforms to `P` via an implied conformance, whose
+/// origin is the explicit conformance to `P2`.
 ///
-/// \c Sub conforms to \c P2 and \c P via inherited conformances,
+/// `Sub` conforms to `P2` and `P` via inherited conformances,
 /// which link back to the conformances described above.
 ///
 /// The enumerators are ordered in terms of decreasing preference:
@@ -137,22 +136,28 @@ enum class DeclContextKind : unsigned {
 /// conformance kinds supersede later conformance kinds, possibly with a
 /// diagnostic (e.g., if an inherited conformance supersedes an
 /// explicit conformance).
+///
+/// - Important: The raw values of these cases are relied upon by
+///   `declared_protocol_conformance_here`.
+///   - If you add a new case, give it an explicit raw value.
+///   - If you change the cases, make sure they remain in sync with the
+///     aforementioned diagnostic.
 enum class ConformanceEntryKind : unsigned {
   /// Inherited from a superclass conformance.
-  Inherited,
+  Inherited = 0,
 
   /// Explicitly specified.
-  Explicit,
+  Explicit = 1,
 
   /// The conformance is generated by a macro that has not been
   /// expanded yet.
-  PreMacroExpansion,
+  PreMacroExpansion = 2,
 
   /// Implicitly synthesized.
-  Synthesized,
+  Synthesized = 3,
 
   /// Implied by an explicitly-specified conformance.
-  Implied,
+  Implied = 4,
 
   Last_Kind = Implied
 };
diff --git a/include/swift/AST/DeclExportabilityVisitor.h b/include/swift/AST/DeclExportabilityVisitor.h
index 6eb9c46c928d9..732113d55a056 100644
--- a/include/swift/AST/DeclExportabilityVisitor.h
+++ b/include/swift/AST/DeclExportabilityVisitor.h
@@ -158,6 +158,7 @@ class DeclExportabilityVisitor
   UNREACHABLE(MissingMember);
   UNREACHABLE(GenericTypeParam);
   UNREACHABLE(Param);
+  UNREACHABLE(Using);
 
 #undef UNREACHABLE
 
diff --git a/include/swift/AST/DeclNameExtractor.h b/include/swift/AST/DeclNameExtractor.h
new file mode 100644
index 0000000000000..92be7502b87b1
--- /dev/null
+++ b/include/swift/AST/DeclNameExtractor.h
@@ -0,0 +1,58 @@
+//===--- DeclNameExtractor.h - Decl Name Demangling -------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the DeclNameExtractor utility.
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/AST/ASTContext.h"
+#include "swift/AST/Identifier.h"
+
+namespace swift {
+namespace Demangle {
+
+class Node;
+
+class DeclNameExtractor {
+private:
+  ASTContext &Ctx;
+
+public:
+  DeclNameExtractor(ASTContext &ctx) : Ctx(ctx) {}
+
+  /// Extract a DeclName from a demangling node
+  /// \returns true if a \c DeclName is found, false otherwise.
+  bool extractDeclName(Node *node, DeclName &name,
+                       Identifier &privateDiscriminator);
+
+private:
+  bool extractIdentifierName(Node *node, DeclName &declName,
+                             Identifier &privateDiscriminator);
+  bool extractFunctionLikeName(Node *node, DeclName &declName,
+                               Identifier &privateDiscriminator);
+  void extractArgLabelsFromLabelList(Node *LabelList,
+                                     SmallVectorImpl<Identifier> &ArgLabels);
+  void extractArgLabelsFromType(Node *Type,
+                                SmallVectorImpl<Identifier> &ArgLabels);
+  DeclBaseName extractOperatorName(Node *node);
+};
+
+/// Returns an identifier with the given name, automatically removing any
+/// surrounding backticks that are present for raw identifiers.
+Identifier getIdentifier(ASTContext &Ctx, StringRef name);
+
+bool extractNameNodeInfo(ASTContext &Ctx, Node *node, StringRef &name,
+                         StringRef &relatedEntityKind,
+                         Identifier &privateDiscriminator);
+
+} // namespace Demangle
+} // namespace swift
diff --git a/include/swift/AST/DeclNameLoc.h b/include/swift/AST/DeclNameLoc.h
index a4a65ef50be99..494a4ae721faf 100644
--- a/include/swift/AST/DeclNameLoc.h
+++ b/include/swift/AST/DeclNameLoc.h
@@ -20,6 +20,8 @@
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/SourceLoc.h"
 
+#include "llvm/ADT/ArrayRef.h"
+
 class BridgedDeclNameLoc;
 
 namespace swift {
@@ -71,6 +73,10 @@ class DeclNameLoc {
   explicit DeclNameLoc(SourceLoc baseNameLoc)
       : DeclNameLoc(baseNameLoc.getOpaquePointerValue(), 0) {}
 
+  explicit DeclNameLoc(ASTContext &ctx, SourceLoc moduleSelectorLoc,
+                       SourceLoc baseNameLoc)
+    : DeclNameLoc(baseNameLoc) { }
+
   /// Create declaration name location information for a compound
   /// name.
   DeclNameLoc(ASTContext &ctx, SourceLoc baseNameLoc,
@@ -78,6 +84,13 @@ class DeclNameLoc {
               ArrayRef<SourceLoc> argumentLabelLocs,
               SourceLoc rParenLoc);
 
+  DeclNameLoc(ASTContext &ctx, SourceLoc moduleSelectorLoc,
+              SourceLoc baseNameLoc,
+              SourceLoc lParenLoc,
+              ArrayRef<SourceLoc> argumentLabelLocs,
+              SourceLoc rParenLoc)
+    : DeclNameLoc(ctx, baseNameLoc, lParenLoc, argumentLabelLocs, rParenLoc) { }
+
   /// Whether the location information is valid.
   bool isValid() const { return getBaseNameLoc().isValid(); }
 
@@ -111,6 +124,10 @@ class DeclNameLoc {
     return getSourceLocs()[FirstArgumentLabelIndex + index];
   }
 
+  SourceLoc getModuleSelectorLoc() const {
+    return SourceLoc();
+  }
+
   SourceLoc getStartLoc() const {
     return getBaseNameLoc();
   }
diff --git a/include/swift/AST/DeclNodes.def b/include/swift/AST/DeclNodes.def
index 2f02c4bf5aac8..ef83c8a92777f 100644
--- a/include/swift/AST/DeclNodes.def
+++ b/include/swift/AST/DeclNodes.def
@@ -190,6 +190,7 @@ DECL(Missing, Decl)
 DECL(MissingMember, Decl)
 DECL(PatternBinding, Decl)
 DECL(EnumCase, Decl)
+DECL(Using, Decl)
 
 ABSTRACT_DECL(Operator, Decl)
   OPERATOR_DECL(InfixOperator, OperatorDecl)
diff --git a/include/swift/AST/DiagnosticArgument.h b/include/swift/AST/DiagnosticArgument.h
new file mode 100644
index 0000000000000..9f8652db72eaf
--- /dev/null
+++ b/include/swift/AST/DiagnosticArgument.h
@@ -0,0 +1,213 @@
+//===--- DiagnosticArgument.h -----------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_AST_DIAGNOSTIC_ARGUMENT_H
+#define SWIFT_AST_DIAGNOSTIC_ARGUMENT_H
+
+#include "swift/AST/ActorIsolation.h"
+#include "swift/AST/AvailabilityDomain.h"
+#include "swift/AST/DiagnosticConsumer.h"
+#include "swift/AST/Identifier.h"
+#include "swift/AST/LayoutConstraint.h"
+#include "swift/AST/TypeLoc.h"
+#include "swift/Basic/Version.h"
+#include "llvm/Support/VersionTuple.h"
+
+namespace clang {
+class NamedDecl;
+class Type;
+} // namespace clang
+
+namespace swift {
+
+class Decl;
+class DeclAttribute;
+class TypeAttribute;
+class TypeRepr;
+
+enum class DescriptivePatternKind : uint8_t;
+enum class DescriptiveDeclKind : uint8_t;
+enum class ReferenceOwnership : uint8_t;
+enum class SelfAccessKind : uint8_t;
+enum class StaticSpellingKind : uint8_t;
+enum class StmtKind;
+
+/// A family of wrapper types for compiler data types that forces its
+/// underlying data to be formatted with full qualification.
+///
+/// So far, this is only useful for \c Type, hence the SFINAE'ing.
+template <typename T, typename = void>
+struct FullyQualified {};
+
+template <typename T>
+struct FullyQualified<
+    T, typename std::enable_if<std::is_convertible<T, Type>::value>::type> {
+  Type t;
+
+public:
+  FullyQualified(T t) : t(t) {};
+
+  Type getType() const { return t; }
+};
+
+struct WitnessType {
+  Type t;
+
+  WitnessType(Type t) : t(t) {}
+
+  Type getType() { return t; }
+};
+
+/// Describes the kind of diagnostic argument we're storing.
+enum class DiagnosticArgumentKind {
+  String,
+  Integer,
+  Unsigned,
+  Identifier,
+  ObjCSelector,
+  Decl,
+  Type,
+  TypeRepr,
+  FullyQualifiedType,
+  WitnessType,
+  DescriptivePatternKind,
+  SelfAccessKind,
+  ReferenceOwnership,
+  StaticSpellingKind,
+  DescriptiveDeclKind,
+  DescriptiveStmtKind,
+  DeclAttribute,
+  TypeAttribute,
+  AvailabilityDomain,
+  AvailabilityRange,
+  VersionTuple,
+  LayoutConstraint,
+  ActorIsolation,
+  IsolationSource,
+  Diagnostic,
+  ClangDecl,
+  ClangType,
+};
+
+/// Variant type that holds a single diagnostic argument of a known
+/// type.
+///
+/// All diagnostic arguments are converted to an instance of this class.
+class DiagnosticArgument {
+  DiagnosticArgumentKind Kind;
+  union {
+    int IntegerVal;
+    unsigned UnsignedVal;
+    StringRef StringVal;
+    DeclNameRef IdentifierVal;
+    ObjCSelector ObjCSelectorVal;
+    const Decl *TheDecl;
+    Type TypeVal;
+    TypeRepr *TyR;
+    FullyQualified<Type> FullyQualifiedTypeVal;
+    WitnessType WitnessTypeVal;
+    DescriptivePatternKind DescriptivePatternKindVal;
+    SelfAccessKind SelfAccessKindVal;
+    ReferenceOwnership ReferenceOwnershipVal;
+    StaticSpellingKind StaticSpellingKindVal;
+    DescriptiveDeclKind DescriptiveDeclKindVal;
+    StmtKind DescriptiveStmtKindVal;
+    const DeclAttribute *DeclAttributeVal;
+    const TypeAttribute *TypeAttributeVal;
+    AvailabilityDomain AvailabilityDomainVal;
+    AvailabilityRange AvailabilityRangeVal;
+    llvm::VersionTuple VersionVal;
+    LayoutConstraint LayoutConstraintVal;
+    ActorIsolation ActorIsolationVal;
+    IsolationSource IsolationSourceVal;
+    DiagnosticInfo *DiagnosticVal;
+    const clang::NamedDecl *ClangDecl;
+    const clang::Type *ClangType;
+  };
+
+public:
+  DiagnosticArgument(StringRef S);
+  DiagnosticArgument(int I);
+  DiagnosticArgument(unsigned I);
+  DiagnosticArgument(DeclNameRef R);
+  DiagnosticArgument(DeclName D);
+  DiagnosticArgument(DeclBaseName D);
+  DiagnosticArgument(Identifier I);
+  DiagnosticArgument(ObjCSelector S);
+  DiagnosticArgument(const Decl *VD);
+  DiagnosticArgument(Type T);
+  DiagnosticArgument(TypeRepr *T);
+  DiagnosticArgument(FullyQualified<Type> FQT);
+  DiagnosticArgument(WitnessType WT);
+  DiagnosticArgument(const TypeLoc &TL);
+  DiagnosticArgument(DescriptivePatternKind DPK);
+  DiagnosticArgument(ReferenceOwnership RO);
+  DiagnosticArgument(SelfAccessKind SAK);
+  DiagnosticArgument(StaticSpellingKind SSK);
+  DiagnosticArgument(DescriptiveDeclKind DDK);
+  DiagnosticArgument(StmtKind SK);
+  DiagnosticArgument(const DeclAttribute *attr);
+  DiagnosticArgument(const TypeAttribute *attr);
+  DiagnosticArgument(const AvailabilityDomain domain);
+  DiagnosticArgument(const AvailabilityRange &range);
+  DiagnosticArgument(llvm::VersionTuple version);
+  DiagnosticArgument(LayoutConstraint L);
+  DiagnosticArgument(ActorIsolation AI);
+  DiagnosticArgument(IsolationSource IS);
+  DiagnosticArgument(DiagnosticInfo *D);
+  DiagnosticArgument(const clang::NamedDecl *ND);
+  DiagnosticArgument(const clang::Type *Ty);
+
+  /// Initializes a diagnostic argument using the underlying type of the
+  /// given enum.
+  template <
+      typename EnumType,
+      typename std::enable_if<std::is_enum<EnumType>::value>::type * = nullptr>
+  DiagnosticArgument(EnumType value)
+      : DiagnosticArgument(
+            static_cast<typename std::underlying_type<EnumType>::type>(value)) {
+  }
+
+  DiagnosticArgumentKind getKind() const;
+
+  StringRef getAsString() const;
+  int getAsInteger() const;
+  unsigned getAsUnsigned() const;
+  DeclNameRef getAsIdentifier() const;
+  ObjCSelector getAsObjCSelector() const;
+  const Decl *getAsDecl() const;
+  Type getAsType() const;
+  TypeRepr *getAsTypeRepr() const;
+  FullyQualified<Type> getAsFullyQualifiedType() const;
+  WitnessType getAsWitnessType() const;
+  DescriptivePatternKind getAsDescriptivePatternKind() const;
+  ReferenceOwnership getAsReferenceOwnership() const;
+  SelfAccessKind getAsSelfAccessKind() const;
+  StaticSpellingKind getAsStaticSpellingKind() const;
+  DescriptiveDeclKind getAsDescriptiveDeclKind() const;
+  StmtKind getAsDescriptiveStmtKind() const;
+  const DeclAttribute *getAsDeclAttribute() const;
+  const TypeAttribute *getAsTypeAttribute() const;
+  const AvailabilityDomain getAsAvailabilityDomain() const;
+  const AvailabilityRange getAsAvailabilityRange() const;
+  llvm::VersionTuple getAsVersionTuple() const;
+  LayoutConstraint getAsLayoutConstraint() const;
+  ActorIsolation getAsActorIsolation() const;
+  IsolationSource getAsIsolationSource() const;
+  DiagnosticInfo *getAsDiagnostic() const;
+  const clang::NamedDecl *getAsClangDecl() const;
+  const clang::Type *getAsClangType() const;
+};
+
+} // namespace swift
+
+#endif /* SWIFT_AST_DIAGNOSTIC_ARGUMENT_H */
diff --git a/include/swift/AST/DiagnosticBridge.h b/include/swift/AST/DiagnosticBridge.h
index b110f530e9b6b..81a161aa3a549 100644
--- a/include/swift/AST/DiagnosticBridge.h
+++ b/include/swift/AST/DiagnosticBridge.h
@@ -46,6 +46,10 @@ class DiagnosticBridge {
   void enqueueDiagnostic(SourceManager &SM, const DiagnosticInfo &Info,
                          unsigned innermostBufferID);
 
+  /// Emit a single diagnostic without location information.
+  void emitDiagnosticWithoutLocation(
+      const DiagnosticInfo &Info, llvm::raw_ostream &out, bool forceColors);
+
   /// Flush all enqueued diagnostics.
   void flush(llvm::raw_ostream &OS, bool includeTrailingBreak,
              bool forceColors);
diff --git a/include/swift/AST/DiagnosticConsumer.h b/include/swift/AST/DiagnosticConsumer.h
index 51730e0202fc1..0ca6cb99c8c45 100644
--- a/include/swift/AST/DiagnosticConsumer.h
+++ b/include/swift/AST/DiagnosticConsumer.h
@@ -19,6 +19,7 @@
 #ifndef SWIFT_BASIC_DIAGNOSTICCONSUMER_H
 #define SWIFT_BASIC_DIAGNOSTICCONSUMER_H
 
+#include "swift/AST/DiagnosticKind.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/SourceLoc.h"
 #include "llvm/Support/SourceMgr.h"
@@ -30,15 +31,6 @@ namespace swift {
   class SourceManager;
   enum class DiagID : uint32_t;
 
-/// Describes the kind of diagnostic.
-///
-enum class DiagnosticKind : uint8_t {
-  Error,
-  Warning,
-  Remark,
-  Note
-};
-
 /// Information about a diagnostic passed to DiagnosticConsumers.
 struct DiagnosticInfo {
   DiagID ID = DiagID(0);
diff --git a/include/swift/AST/DiagnosticEngine.h b/include/swift/AST/DiagnosticEngine.h
index 56c9868b0593a..5cb88a4fd822a 100644
--- a/include/swift/AST/DiagnosticEngine.h
+++ b/include/swift/AST/DiagnosticEngine.h
@@ -18,9 +18,8 @@
 #ifndef SWIFT_BASIC_DIAGNOSTICENGINE_H
 #define SWIFT_BASIC_DIAGNOSTICENGINE_H
 
-#include "swift/AST/ActorIsolation.h"
-#include "swift/AST/AvailabilityDomain.h"
 #include "swift/AST/DeclNameLoc.h"
+#include "swift/AST/DiagnosticArgument.h"
 #include "swift/AST/DiagnosticConsumer.h"
 #include "swift/AST/TypeLoc.h"
 #include "swift/Basic/PrintDiagnosticNamesMode.h"
@@ -35,7 +34,6 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/SaveAndRestore.h"
-#include "llvm/Support/VersionTuple.h"
 
 namespace clang {
 class NamedDecl;
@@ -43,27 +41,15 @@ class Type;
 }
 
 namespace swift {
-  class ConstructorDecl;
   class ClosureExpr;
   class Decl;
   class DeclAttribute;
   class DiagnosticEngine;
   class FuncDecl;
-  class GeneratedSourceInfo;
   class SourceManager;
-  class TypeAliasDecl;
-  class ValueDecl;
   class SourceFile;
-
-  enum class CXXStdlibKind : uint8_t;
-  enum class DescriptivePatternKind : uint8_t;
-  enum class DiagGroupID : uint16_t;
-  enum class SelfAccessKind : uint8_t;
-  enum class ReferenceOwnership : uint8_t;
-  enum class StaticSpellingKind : uint8_t;
-  enum class DescriptiveDeclKind : uint8_t;
-  enum class DeclAttrKind : unsigned;
-  enum class StmtKind;
+  class ParamDecl;
+  class AnyPattern;
 
   /// Enumeration describing all of possible diagnostics.
   ///
@@ -101,371 +87,10 @@ namespace swift {
   using DiagArgTuple =
     std::tuple<typename detail::PassArgument<ArgTypes>::type...>;
 
-  /// A family of wrapper types for compiler data types that forces its
-  /// underlying data to be formatted with full qualification.
-  ///
-  /// So far, this is only useful for \c Type, hence the SFINAE'ing.
-  template <typename T, typename = void> struct FullyQualified {};
-
-  template <typename T>
-  struct FullyQualified<
-      T, typename std::enable_if<std::is_convertible<T, Type>::value>::type> {
-    Type t;
-
-  public:
-    FullyQualified(T t) : t(t){};
-
-    Type getType() const { return t; }
-  };
-
-  struct WitnessType {
-    Type t;
-
-    WitnessType(Type t) : t(t) {}
-
-    Type getType() { return t; }
-  };
-
-  /// Describes the kind of diagnostic argument we're storing.
-  ///
-  enum class DiagnosticArgumentKind {
-    String,
-    Integer,
-    Unsigned,
-    Identifier,
-    ObjCSelector,
-    Decl,
-    Type,
-    TypeRepr,
-    FullyQualifiedType,
-    WitnessType,
-    DescriptivePatternKind,
-    SelfAccessKind,
-    ReferenceOwnership,
-    StaticSpellingKind,
-    DescriptiveDeclKind,
-    DescriptiveStmtKind,
-    DeclAttribute,
-    AvailabilityDomain,
-    AvailabilityRange,
-    VersionTuple,
-    LayoutConstraint,
-    ActorIsolation,
-    IsolationSource,
-    Diagnostic,
-    ClangDecl,
-    ClangType,
-  };
-
   namespace diag {
     enum class RequirementKind : uint8_t;
   }
 
-  /// Variant type that holds a single diagnostic argument of a known
-  /// type.
-  ///
-  /// All diagnostic arguments are converted to an instance of this class.
-  class DiagnosticArgument {
-    DiagnosticArgumentKind Kind;
-    union {
-      int IntegerVal;
-      unsigned UnsignedVal;
-      StringRef StringVal;
-      DeclNameRef IdentifierVal;
-      ObjCSelector ObjCSelectorVal;
-      const Decl *TheDecl;
-      Type TypeVal;
-      TypeRepr *TyR;
-      FullyQualified<Type> FullyQualifiedTypeVal;
-      WitnessType WitnessTypeVal;
-      DescriptivePatternKind DescriptivePatternKindVal;
-      SelfAccessKind SelfAccessKindVal;
-      ReferenceOwnership ReferenceOwnershipVal;
-      StaticSpellingKind StaticSpellingKindVal;
-      DescriptiveDeclKind DescriptiveDeclKindVal;
-      StmtKind DescriptiveStmtKindVal;
-      const DeclAttribute *DeclAttributeVal;
-      AvailabilityDomain AvailabilityDomainVal;
-      AvailabilityRange AvailabilityRangeVal;
-      llvm::VersionTuple VersionVal;
-      LayoutConstraint LayoutConstraintVal;
-      ActorIsolation ActorIsolationVal;
-      IsolationSource IsolationSourceVal;
-      DiagnosticInfo *DiagnosticVal;
-      const clang::NamedDecl *ClangDecl;
-      const clang::Type *ClangType;
-    };
-    
-  public:
-    DiagnosticArgument(StringRef S)
-      : Kind(DiagnosticArgumentKind::String), StringVal(S) {
-    }
-
-    DiagnosticArgument(int I) 
-      : Kind(DiagnosticArgumentKind::Integer), IntegerVal(I) {
-    }
-
-    DiagnosticArgument(unsigned I) 
-      : Kind(DiagnosticArgumentKind::Unsigned), UnsignedVal(I) {
-    }
-
-    DiagnosticArgument(DeclNameRef R)
-        : Kind(DiagnosticArgumentKind::Identifier), IdentifierVal(R) {}
-
-    DiagnosticArgument(DeclName D)
-        : Kind(DiagnosticArgumentKind::Identifier),
-          IdentifierVal(DeclNameRef(D)) {}
-
-    DiagnosticArgument(DeclBaseName D)
-        : Kind(DiagnosticArgumentKind::Identifier),
-          IdentifierVal(DeclNameRef(D)) {}
-
-    DiagnosticArgument(Identifier I)
-      : Kind(DiagnosticArgumentKind::Identifier),
-        IdentifierVal(DeclNameRef(I)) {
-    }
-
-    DiagnosticArgument(ObjCSelector S)
-      : Kind(DiagnosticArgumentKind::ObjCSelector), ObjCSelectorVal(S) {
-    }
-
-    DiagnosticArgument(const Decl *VD)
-      : Kind(DiagnosticArgumentKind::Decl), TheDecl(VD) {
-    }
-
-    DiagnosticArgument(Type T)
-      : Kind(DiagnosticArgumentKind::Type), TypeVal(T) {
-    }
-
-    DiagnosticArgument(TypeRepr *T)
-      : Kind(DiagnosticArgumentKind::TypeRepr), TyR(T) {
-    }
-
-    DiagnosticArgument(FullyQualified<Type> FQT)
-        : Kind(DiagnosticArgumentKind::FullyQualifiedType),
-          FullyQualifiedTypeVal(FQT) {}
-
-    DiagnosticArgument(WitnessType WT)
-        : Kind(DiagnosticArgumentKind::WitnessType),
-          WitnessTypeVal(WT) {}
-
-    DiagnosticArgument(const TypeLoc &TL) {
-      if (TypeRepr *tyR = TL.getTypeRepr()) {
-        Kind = DiagnosticArgumentKind::TypeRepr;
-        TyR = tyR;
-      } else {
-        Kind = DiagnosticArgumentKind::Type;
-        TypeVal = TL.getType();
-      }
-    }
-
-    DiagnosticArgument(DescriptivePatternKind DPK)
-        : Kind(DiagnosticArgumentKind::DescriptivePatternKind),
-          DescriptivePatternKindVal(DPK) {}
-
-    DiagnosticArgument(ReferenceOwnership RO)
-        : Kind(DiagnosticArgumentKind::ReferenceOwnership),
-          ReferenceOwnershipVal(RO) {}
-
-    DiagnosticArgument(SelfAccessKind SAK)
-        : Kind(DiagnosticArgumentKind::SelfAccessKind),
-          SelfAccessKindVal(SAK) {}
-
-    DiagnosticArgument(StaticSpellingKind SSK)
-        : Kind(DiagnosticArgumentKind::StaticSpellingKind),
-          StaticSpellingKindVal(SSK) {}
-
-    DiagnosticArgument(DescriptiveDeclKind DDK)
-        : Kind(DiagnosticArgumentKind::DescriptiveDeclKind),
-          DescriptiveDeclKindVal(DDK) {}
-
-    DiagnosticArgument(StmtKind SK)
-        : Kind(DiagnosticArgumentKind::DescriptiveStmtKind),
-          DescriptiveStmtKindVal(SK) {}
-
-    DiagnosticArgument(const DeclAttribute *attr)
-        : Kind(DiagnosticArgumentKind::DeclAttribute),
-          DeclAttributeVal(attr) {}
-
-    DiagnosticArgument(const AvailabilityDomain domain)
-        : Kind(DiagnosticArgumentKind::AvailabilityDomain),
-          AvailabilityDomainVal(domain) {}
-
-    DiagnosticArgument(const AvailabilityRange &range)
-        : Kind(DiagnosticArgumentKind::AvailabilityRange),
-          AvailabilityRangeVal(range) {}
-
-    DiagnosticArgument(llvm::VersionTuple version)
-      : Kind(DiagnosticArgumentKind::VersionTuple),
-        VersionVal(version) { }
-
-    DiagnosticArgument(LayoutConstraint L)
-      : Kind(DiagnosticArgumentKind::LayoutConstraint), LayoutConstraintVal(L) {
-    }
-
-    DiagnosticArgument(ActorIsolation AI)
-      : Kind(DiagnosticArgumentKind::ActorIsolation),
-        ActorIsolationVal(AI) {
-    }
-
-    DiagnosticArgument(IsolationSource IS)
-      : Kind(DiagnosticArgumentKind::IsolationSource),
-        IsolationSourceVal(IS){
-    }
-
-    DiagnosticArgument(DiagnosticInfo *D)
-      : Kind(DiagnosticArgumentKind::Diagnostic),
-        DiagnosticVal(D) {
-    }
-
-    DiagnosticArgument(const clang::NamedDecl *ND)
-        : Kind(DiagnosticArgumentKind::ClangDecl), ClangDecl(ND) {}
-
-    DiagnosticArgument(const clang::Type *Ty)
-        : Kind(DiagnosticArgumentKind::ClangType), ClangType(Ty) {}
-
-    /// Initializes a diagnostic argument using the underlying type of the
-    /// given enum.
-    template<
-        typename EnumType,
-        typename std::enable_if<std::is_enum<EnumType>::value>::type* = nullptr>
-    DiagnosticArgument(EnumType value)
-      : DiagnosticArgument(
-          static_cast<typename std::underlying_type<EnumType>::type>(value)) {}
-
-    DiagnosticArgumentKind getKind() const { return Kind; }
-
-    StringRef getAsString() const {
-      assert(Kind == DiagnosticArgumentKind::String);
-      return StringVal;
-    }
-
-    int getAsInteger() const {
-      assert(Kind == DiagnosticArgumentKind::Integer);
-      return IntegerVal;
-    }
-
-    unsigned getAsUnsigned() const {
-      assert(Kind == DiagnosticArgumentKind::Unsigned);
-      return UnsignedVal;
-    }
-
-    DeclNameRef getAsIdentifier() const {
-      assert(Kind == DiagnosticArgumentKind::Identifier);
-      return IdentifierVal;
-    }
-
-    ObjCSelector getAsObjCSelector() const {
-      assert(Kind == DiagnosticArgumentKind::ObjCSelector);
-      return ObjCSelectorVal;
-    }
-
-    const Decl *getAsDecl() const {
-      assert(Kind == DiagnosticArgumentKind::Decl);
-      return TheDecl;
-    }
-
-    Type getAsType() const {
-      assert(Kind == DiagnosticArgumentKind::Type);
-      return TypeVal;
-    }
-
-    TypeRepr *getAsTypeRepr() const {
-      assert(Kind == DiagnosticArgumentKind::TypeRepr);
-      return TyR;
-    }
-
-    FullyQualified<Type> getAsFullyQualifiedType() const {
-      assert(Kind == DiagnosticArgumentKind::FullyQualifiedType);
-      return FullyQualifiedTypeVal;
-    }
-
-    WitnessType getAsWitnessType() const {
-      assert(Kind == DiagnosticArgumentKind::WitnessType);
-      return WitnessTypeVal;
-    }
-
-    DescriptivePatternKind getAsDescriptivePatternKind() const {
-      assert(Kind == DiagnosticArgumentKind::DescriptivePatternKind);
-      return DescriptivePatternKindVal;
-    }
-
-    ReferenceOwnership getAsReferenceOwnership() const {
-      assert(Kind == DiagnosticArgumentKind::ReferenceOwnership);
-      return ReferenceOwnershipVal;
-    }
-
-    SelfAccessKind getAsSelfAccessKind() const {
-      assert(Kind == DiagnosticArgumentKind::SelfAccessKind);
-      return SelfAccessKindVal;
-    }
-
-    StaticSpellingKind getAsStaticSpellingKind() const {
-      assert(Kind == DiagnosticArgumentKind::StaticSpellingKind);
-      return StaticSpellingKindVal;
-    }
-
-    DescriptiveDeclKind getAsDescriptiveDeclKind() const {
-      assert(Kind == DiagnosticArgumentKind::DescriptiveDeclKind);
-      return DescriptiveDeclKindVal;
-    }
-
-    StmtKind getAsDescriptiveStmtKind() const {
-      assert(Kind == DiagnosticArgumentKind::DescriptiveStmtKind);
-      return DescriptiveStmtKindVal;
-    }
-
-    const DeclAttribute *getAsDeclAttribute() const {
-      assert(Kind == DiagnosticArgumentKind::DeclAttribute);
-      return DeclAttributeVal;
-    }
-
-    const AvailabilityDomain getAsAvailabilityDomain() const {
-      assert(Kind == DiagnosticArgumentKind::AvailabilityDomain);
-      return AvailabilityDomainVal;
-    }
-
-    const AvailabilityRange getAsAvailabilityRange() const {
-      assert(Kind == DiagnosticArgumentKind::AvailabilityRange);
-      return AvailabilityRangeVal;
-    }
-
-    llvm::VersionTuple getAsVersionTuple() const {
-      assert(Kind == DiagnosticArgumentKind::VersionTuple);
-      return VersionVal;
-    }
-
-    LayoutConstraint getAsLayoutConstraint() const {
-      assert(Kind == DiagnosticArgumentKind::LayoutConstraint);
-      return LayoutConstraintVal;
-    }
-
-    ActorIsolation getAsActorIsolation() const {
-      assert(Kind == DiagnosticArgumentKind::ActorIsolation);
-      return ActorIsolationVal;
-    }
-
-    IsolationSource getAsIsolationSource() const {
-      assert(Kind == DiagnosticArgumentKind::IsolationSource);
-      return IsolationSourceVal;
-    }
-
-    DiagnosticInfo *getAsDiagnostic() const {
-      assert(Kind == DiagnosticArgumentKind::Diagnostic);
-      return DiagnosticVal;
-    }
-
-    const clang::NamedDecl *getAsClangDecl() const {
-      assert(Kind == DiagnosticArgumentKind::ClangDecl);
-      return ClangDecl;
-    }
-
-    const clang::Type *getAsClangType() const {
-      assert(Kind == DiagnosticArgumentKind::ClangType);
-      return ClangType;
-    }
-  };
-
   /// Describes the current behavior to take with a diagnostic.
   /// Ordered from most severe to least.
   struct DiagnosticBehavior {
@@ -594,6 +219,9 @@ namespace swift {
     const class Decl *getDecl() const { return Decl; }
     DiagnosticBehavior getBehaviorLimit() const { return BehaviorLimit; }
 
+    /// Retrieve the stored SourceLoc, or the location of the stored Decl.
+    SourceLoc getLocOrDeclLoc() const;
+
     void setLoc(SourceLoc loc) { Loc = loc; }
     void setIsChildNote(bool isChildNote) { IsChildNote = isChildNote; }
     void setDecl(const class Decl *decl) { Decl = decl; }
@@ -656,6 +284,19 @@ namespace swift {
     }
   };
 
+  namespace detail {
+  /// Stores information for an active diagnostic that hasn't been emitted yet.
+  /// This includes both "in-flight" diagnostics as well as diagnostics queued
+  /// for a transaction.
+  struct ActiveDiagnostic {
+    Diagnostic Diag;
+    SmallVector<DiagnosticInfo, 2> WrappedDiagnostics;
+    SmallVector<std::vector<DiagnosticArgument>, 4> WrappedDiagnosticArgs;
+
+    ActiveDiagnostic(Diagnostic diag) : Diag(std::move(diag)) {}
+  };
+  } // namespace detail
+
   /// A diagnostic that has no input arguments, so it is trivially-destructable.
   using ZeroArgDiagnostic = Diag<>;
   
@@ -670,33 +311,40 @@ namespace swift {
     friend class DiagnosticEngine;
     
     DiagnosticEngine *Engine;
+    unsigned Idx;
     bool IsActive;
     
     /// Create a new in-flight diagnostic. 
     ///
     /// This constructor is only available to the DiagnosticEngine.
-    InFlightDiagnostic(DiagnosticEngine &Engine)
-      : Engine(&Engine), IsActive(true) { }
-    
+    InFlightDiagnostic(DiagnosticEngine &Engine, unsigned idx)
+        : Engine(&Engine), Idx(idx), IsActive(true) {}
+
     InFlightDiagnostic(const InFlightDiagnostic &) = delete;
     InFlightDiagnostic &operator=(const InFlightDiagnostic &) = delete;
     InFlightDiagnostic &operator=(InFlightDiagnostic &&) = delete;
 
+    /// Retrieve the underlying active diagnostic information.
+    detail::ActiveDiagnostic &getActiveDiag() const;
+
+    /// Retrieve the underlying diagnostic.
+    Diagnostic &getDiag() const { return getActiveDiag().Diag; }
+
   public:
     /// Create an active but unattached in-flight diagnostic.
     /// 
     /// The resulting diagnostic can be used as a dummy, accepting the
     /// syntax to add additional information to a diagnostic without
     /// actually emitting a diagnostic.
-    InFlightDiagnostic() : Engine(0), IsActive(true) { }
-    
+    InFlightDiagnostic() : Engine(0), Idx(0), IsActive(true) {}
+
     /// Transfer an in-flight diagnostic to a new object, which is
     /// typically used when returning in-flight diagnostics.
     InFlightDiagnostic(InFlightDiagnostic &&Other)
-      : Engine(Other.Engine), IsActive(Other.IsActive) {
+        : Engine(Other.Engine), Idx(Other.Idx), IsActive(Other.IsActive) {
       Other.IsActive = false;
     }
-    
+
     ~InFlightDiagnostic() {
       if (IsActive)
         flush();
@@ -767,6 +415,23 @@ namespace swift {
       return limitBehaviorUntilSwiftVersion(limit, languageMode);
     }
 
+    /// Limit the diagnostic behavior to warning until the next future
+    /// language mode.
+    ///
+    /// This should be preferred over passing the next major version to
+    /// `warnUntilSwiftVersion` to make it easier to find and update clients
+    /// when a new language mode is introduced.
+    ///
+    /// This helps stage in fixes for stricter diagnostics as warnings
+    /// until the next major language version.
+    InFlightDiagnostic &warnUntilFutureSwiftVersion();
+
+    InFlightDiagnostic &warnUntilFutureSwiftVersionIf(bool shouldLimit) {
+      if (!shouldLimit)
+        return *this;
+      return warnUntilFutureSwiftVersion();
+    }
+
     /// Limit the diagnostic behavior to warning until the specified version.
     ///
     /// This helps stage in fixes for stricter diagnostics as warnings
@@ -841,9 +506,6 @@ namespace swift {
 
     static const char *fixItStringFor(const FixItID id);
 
-    /// Get the best location where an 'import' fixit might be offered.
-    SourceLoc getBestAddImportFixItLoc(const Decl *Member) const;
-
     /// Add a token-based replacement fix-it to the currently-active
     /// diagnostic.
     template <typename... ArgTypes>
@@ -959,6 +621,9 @@ namespace swift {
 
     /// Don't emit any warnings
     bool suppressWarnings = false;
+
+    /// Don't emit any notes
+    bool suppressNotes = false;
     
     /// Don't emit any remarks
     bool suppressRemarks = false;
@@ -987,7 +652,10 @@ namespace swift {
 
     /// Figure out the Behavior for the given diagnostic, taking current
     /// state such as fatality into account.
-    DiagnosticBehavior determineBehavior(const Diagnostic &diag);
+    DiagnosticBehavior determineBehavior(const Diagnostic &diag) const;
+
+    /// Updates the diagnostic state for a diagnostic to emit.
+    void updateFor(DiagnosticBehavior behavior);
 
     bool hadAnyError() const { return anyErrorOccurred; }
     bool hasFatalErrorOccurred() const { return fatalErrorOccurred; }
@@ -1003,6 +671,10 @@ namespace swift {
     void setSuppressWarnings(bool val) { suppressWarnings = val; }
     bool getSuppressWarnings() const { return suppressWarnings; }
     
+    /// Whether to skip emitting notes
+    void setSuppressNotes(bool val) { suppressNotes = val; }
+    bool getSuppressNotes() const { return suppressNotes; }
+
     /// Whether to skip emitting remarks
     void setSuppressRemarks(bool val) { suppressRemarks = val; }
     bool getSuppressRemarks() const { return suppressRemarks; }
@@ -1015,7 +687,7 @@ namespace swift {
 
     /// Returns a Boolean value indicating whether warnings belonging to the
     /// diagnostic group identified by `id` should be escalated to errors.
-    bool getWarningsAsErrorsForDiagGroupID(DiagGroupID id) {
+    bool getWarningsAsErrorsForDiagGroupID(DiagGroupID id) const {
       return warningsAsErrors[(unsigned)id];
     }
 
@@ -1041,9 +713,14 @@ namespace swift {
       ignoredDiagnostics[(unsigned)id] = ignored;
     }
 
+    bool isIgnoredDiagnostic(DiagID id) const {
+      return ignoredDiagnostics[(unsigned)id];
+    }
+
     void swap(DiagnosticState &other) {
       std::swap(showDiagnosticsAfterFatalError, other.showDiagnosticsAfterFatalError);
       std::swap(suppressWarnings, other.suppressWarnings);
+      std::swap(suppressNotes, other.suppressNotes);
       std::swap(suppressRemarks, other.suppressRemarks);
       std::swap(warningsAsErrors, other.warningsAsErrors);
       std::swap(fatalErrorOccurred, other.fatalErrorOccurred);
@@ -1144,16 +821,12 @@ namespace swift {
     /// Tracks diagnostic behaviors and state
     DiagnosticState state;
 
-    /// The currently active diagnostic, if there is one.
-    std::optional<Diagnostic> ActiveDiagnostic;
-
-    /// Diagnostics wrapped by ActiveDiagnostic, if any.
-    SmallVector<DiagnosticInfo, 2> WrappedDiagnostics;
-    SmallVector<std::vector<DiagnosticArgument>, 4> WrappedDiagnosticArgs;
+    /// The currently active diagnostics.
+    SmallVector<detail::ActiveDiagnostic, 4> ActiveDiagnostics;
 
     /// All diagnostics that have are no longer active but have not yet
     /// been emitted due to an open transaction.
-    SmallVector<Diagnostic, 4> TentativeDiagnostics;
+    SmallVector<detail::ActiveDiagnostic, 4> TentativeDiagnostics;
 
     llvm::BumpPtrAllocator TransactionAllocator;
     /// A set of all strings involved in current transactional chain.
@@ -1176,6 +849,9 @@ namespace swift {
     /// emitted once all transactions have closed.
     unsigned TransactionCount = 0;
 
+    /// The number of currently in-flight diagnostics.
+    unsigned NumActiveDiags = 0;
+
     /// For batch mode, use this to know where to output a diagnostic from a
     /// non-primary file. It's any location in the buffer of the current primary
     /// input being compiled.
@@ -1211,7 +887,7 @@ namespace swift {
 
   public:
     explicit DiagnosticEngine(SourceManager &SourceMgr)
-        : SourceMgr(SourceMgr), ActiveDiagnostic(),
+        : SourceMgr(SourceMgr), ActiveDiagnostics(),
           TransactionStrings(TransactionAllocator),
           DiagnosticStringsSaver(DiagnosticStringsAllocator) {}
 
@@ -1230,6 +906,7 @@ namespace swift {
     }
 
     void flushConsumers() {
+      ASSERT(NumActiveDiags == 0 && "Expected in-flight diags to be flushed");
       for (auto consumer : Consumers)
         consumer->flush();
     }
@@ -1240,6 +917,12 @@ namespace swift {
       return state.getSuppressWarnings();
     }
 
+    /// Whether to skip emitting notes
+    void setSuppressNotes(bool val) { state.setSuppressNotes(val); }
+    bool getSuppressNotes() const {
+      return state.getSuppressNotes();
+    }
+
     /// Whether to skip emitting remarks
     void setSuppressRemarks(bool val) { state.setSuppressRemarks(val); }
     bool getSuppressRemarks() const {
@@ -1287,6 +970,10 @@ namespace swift {
       state.setIgnoredDiagnostic(id, true);
     }
 
+    bool isIgnoredDiagnostic(DiagID id) const {
+      return state.isIgnoredDiagnostic(id);
+    }
+
     void resetHadAnyError() {
       state.resetHadAnyError();
     }
@@ -1361,10 +1048,9 @@ namespace swift {
     /// \returns An in-flight diagnostic, to which additional information can
     /// be attached.
     InFlightDiagnostic diagnose(SourceLoc Loc, const Diagnostic &D) {
-      assert(!ActiveDiagnostic && "Already have an active diagnostic");
-      ActiveDiagnostic = D;
-      ActiveDiagnostic->setLoc(Loc);
-      return InFlightDiagnostic(*this);
+      auto IFD = beginDiagnostic(D);
+      getActiveDiagnostic(IFD).Diag.setLoc(Loc);
+      return IFD;
     }
     
     /// Emit a diagnostic with the given set of diagnostic arguments.
@@ -1440,10 +1126,9 @@ namespace swift {
     /// \returns An in-flight diagnostic, to which additional information can
     /// be attached.
     InFlightDiagnostic diagnose(const Decl *decl, const Diagnostic &diag) {
-      assert(!ActiveDiagnostic && "Already have an active diagnostic");
-      ActiveDiagnostic = diag;
-      ActiveDiagnostic->setDecl(decl);
-      return InFlightDiagnostic(*this);
+      auto IFD = beginDiagnostic(diag);
+      getActiveDiagnostic(IFD).Diag.setDecl(decl);
+      return IFD;
     }
 
     /// Emit a diagnostic with the given set of diagnostic arguments.
@@ -1497,16 +1182,21 @@ namespace swift {
         DiagnosticFormatOptions FormatOpts = DiagnosticFormatOptions());
 
   private:
+    /// Begins a new in-flight diagnostic.
+    InFlightDiagnostic beginDiagnostic(const Diagnostic &D);
+
+    /// Ends an in-flight diagnostic. Once all in-flight diagnostics have ended,
+    /// they will either be emitted, or captured by an open transaction.
+    void endDiagnostic(const InFlightDiagnostic &D);
+
     /// Called when tentative diagnostic is about to be flushed,
     /// to apply any required transformations e.g. copy string arguments
     /// to extend their lifetime.
     void onTentativeDiagnosticFlush(Diagnostic &diagnostic);
 
-    /// Flush the active diagnostic.
-    void flushActiveDiagnostic();
-    
-    /// Retrieve the active diagnostic.
-    Diagnostic &getActiveDiagnostic() { return *ActiveDiagnostic; }
+    /// Retrieve the stored active diagnostic for a given InFlightDiagnostic.
+    detail::ActiveDiagnostic &
+    getActiveDiagnostic(const InFlightDiagnostic &diag);
 
     /// Generate DiagnosticInfo for a Diagnostic to be passed to consumers.
     std::optional<DiagnosticInfo>
@@ -1522,7 +1212,7 @@ namespace swift {
 
     /// Handle a new diagnostic, which will either be emitted, or added to an
     /// active transaction.
-    void handleDiagnostic(Diagnostic &&diag);
+    void handleDiagnostic(detail::ActiveDiagnostic &&diag);
 
     /// Clear any tentative diagnostics.
     void clearTentativeDiagnostics();
@@ -1561,11 +1251,7 @@ namespace swift {
     SourceLoc getDefaultDiagnosticLoc() const {
       return bufferIndirectlyCausingDiagnostic;
     }
-    SourceLoc getBestAddImportFixItLoc(const Decl *Member,
-                                       SourceFile *sourceFile) const;
-    SourceLoc getBestAddImportFixItLoc(const Decl *Member) const {
-      return getBestAddImportFixItLoc(Member, nullptr);
-    }
+    SourceLoc getBestAddImportFixItLoc(SourceFile *sf) const;
   };
 
   inline SourceManager &InFlightDiagnostic::getSourceManager() {
@@ -1655,12 +1341,12 @@ namespace swift {
     }
 
     bool hasErrors() const {
-      ArrayRef<Diagnostic> diagnostics(Engine.TentativeDiagnostics.begin() +
-                                           PrevDiagnostics,
-                                       Engine.TentativeDiagnostics.end());
+      ArrayRef<detail::ActiveDiagnostic> diagnostics(
+          Engine.TentativeDiagnostics.begin() + PrevDiagnostics,
+          Engine.TentativeDiagnostics.end());
 
       for (auto &diagnostic : diagnostics) {
-        auto behavior = Engine.state.determineBehavior(diagnostic);
+        auto behavior = Engine.state.determineBehavior(diagnostic.Diag);
         if (behavior == DiagnosticBehavior::Fatal ||
             behavior == DiagnosticBehavior::Error)
           return true;
@@ -1725,14 +1411,14 @@ namespace swift {
 
       // The first diagnostic is assumed to be the parent. If this is not an
       // error or warning, we'll assert later when trying to add children.
-      Diagnostic &parent = Engine.TentativeDiagnostics[PrevDiagnostics];
+      Diagnostic &parent = Engine.TentativeDiagnostics[PrevDiagnostics].Diag;
 
       // Associate the children with the parent.
       for (auto diag =
                Engine.TentativeDiagnostics.begin() + PrevDiagnostics + 1;
            diag != Engine.TentativeDiagnostics.end(); ++diag) {
-        diag->setIsChildNote(true);
-        parent.addChildNote(std::move(*diag));
+        diag->Diag.setIsChildNote(true);
+        parent.addChildNote(std::move(diag->Diag));
       }
 
       // Erase the children, they'll be emitted alongside their parent.
@@ -1792,6 +1478,13 @@ namespace swift {
     /// Retrieve the underlying engine which will receive the diagnostics.
     DiagnosticEngine &getUnderlyingDiags() const { return UnderlyingEngine; }
 
+    /// Iterates over each captured diagnostic, running a lambda with it.
+    void forEach(llvm::function_ref<void(const Diagnostic &)> body) const;
+
+    /// Filters the queued diagnostics, dropping any where the predicate
+    /// returns \c false.
+    void filter(llvm::function_ref<bool(const Diagnostic &)> predicate);
+
     /// Clear this queue and erase all diagnostics recorded.
     void clear() {
       assert(QueueEngine.TransactionCount == 1 &&
diff --git a/include/swift/AST/DiagnosticGroups.def b/include/swift/AST/DiagnosticGroups.def
index 0b93805b8f417..4f55336d1ed97 100644
--- a/include/swift/AST/DiagnosticGroups.def
+++ b/include/swift/AST/DiagnosticGroups.def
@@ -12,6 +12,24 @@
 //
 //  This file defines diagnostic groups and links between them.
 //
+//  The GROUP(Name, Filename) macro is used to define each diagnostic group.
+//  These groups are used to associate documentation with particular set of
+//  diagnostics and also to provide more control over whether the warnings
+//  in the group are escalated to errors (via the -Wwarning and -Werror flags.)
+//  A given warning or error can be associated with a diagnostic group by using
+//  GROUPED_WARNING or GROUPED_ERROR, respectively. New warnings and errors
+//  should be introduced along with groups to improve documentation.
+//
+//    - Name: the name of the group that will be shown in diagnostic messages
+//      (e.g., StrictMemorySafety) and used in command-line options like
+//      -Wwarning and -Werror. Once assigned, the group name for a particular
+//      diagnostic should not be changed, because it will affect existing users
+//      of the command-line flags.
+//    - Filename: the name of the file that provides documentation for this
+//      diagnostic group. There should be a corresponding Markdown file in
+//      userdocs/diagnostics providing short-form documentation that helps
+//      explain the diagnostic and how to resolve the problem.
+//
 //===----------------------------------------------------------------------===//
 
 #define DEFINE_DIAGNOSTIC_GROUPS_MACROS
@@ -22,31 +40,50 @@
 
 GROUP(no_group, "")
 
-GROUP(ActorIsolatedCall, "actor-isolated-call.md")
-GROUP(AsyncCallerExecution, "async-caller-execution.md")
-GROUP(ConformanceIsolation, "conformance-isolation.md")
-GROUP(DeprecatedDeclaration, "deprecated-declaration.md")
-GROUP(DynamicCallable, "dynamic-callable-requirements.md")
-GROUP(ErrorInFutureSwiftVersion, "error-in-future-swift-version.md")
-GROUP(ExistentialAny, "existential-any.md")
-GROUP(ExistentialMemberAccess, "existential-member-access-limitations.md")
-GROUP(IsolatedConformances, "isolated-conformances.md")
-GROUP(MultipleInheritance, "multiple-inheritance.md")
-GROUP(MutableGlobalVariable, "mutable-global-variable.md")
-GROUP(NominalTypes, "nominal-types.md")
-GROUP(OpaqueTypeInference, "opaque-type-inference.md")
-GROUP(PreconcurrencyImport, "preconcurrency-import.md")
-GROUP(PropertyWrappers, "property-wrapper-requirements.md")
-GROUP(ProtocolTypeNonConformance, "protocol-type-non-conformance.md")
-GROUP(ResultBuilderMethods, "result-builder-methods.md")
-GROUP(SendableClosureCaptures, "sendable-closure-captures.md")
-GROUP(SendingRisksDataRace, "sending-risks-data-race.md")
-GROUP(StrictLanguageFeatures, "strict-language-features.md")
-GROUP(StrictMemorySafety, "strict-memory-safety.md")
-GROUP(StringInterpolationConformance, "string-interpolation-conformance.md")
-GROUP(TemporaryPointers, "temporary-pointers.md")
-GROUP(TrailingClosureMatching, "trailing-closure-matching.md")
-GROUP(UnknownWarningGroup, "unknown-warning-group.md")
+GROUP(ActorIsolatedCall, "actor-isolated-call")
+GROUP(AlwaysAvailableDomain, "always-available-domain")
+GROUP(AvailabilityUnrecognizedName, "availability-unrecognized-name")
+GROUP(ClangDeclarationImport, "clang-declaration-import")
+GROUP(ConformanceIsolation, "conformance-isolation")
+GROUP(DeprecatedDeclaration, "deprecated-declaration")
+GROUP(DynamicCallable, "dynamic-callable-requirements")
+GROUP(EmbeddedRestrictions, "embedded-restrictions")
+GROUP(ErrorInFutureSwiftVersion, "error-in-future-swift-version")
+GROUP(ExclusivityViolation, "exclusivity-violation")
+GROUP(ExistentialAny, "existential-any")
+GROUP(ExistentialMemberAccess, "existential-member-access-limitations")
+GROUP(ImplementationOnlyDeprecated, "implementation-only-deprecated")
+GROUP(IsolatedConformances, "isolated-conformances")
+GROUP(MemberImportVisibility, "member-import-visibility")
+GROUP(MissingModuleOnKnownPaths, "missing-module-on-known-paths")
+GROUP(ModuleNotTestable, "module-not-testable")
+GROUP(ModuleVersionMissing, "module-version-missing")
+GROUP(MultipleInheritance, "multiple-inheritance")
+GROUP(MutableGlobalVariable, "mutable-global-variable")
+GROUP(NominalTypes, "nominal-types")
+GROUP(NonisolatedNonsendingByDefault, "nonisolated-nonsending-by-default")
+GROUP(OpaqueTypeInference, "opaque-type-inference")
+GROUP(PreconcurrencyImport, "preconcurrency-import")
+GROUP(PropertyWrappers, "property-wrapper-requirements")
+GROUP(ProtocolTypeNonConformance, "protocol-type-non-conformance")
+GROUP(ResultBuilderMethods, "result-builder-methods")
+GROUP(SendableClosureCaptures, "sendable-closure-captures")
+GROUP(SendableMetatypes, "sendable-metatypes")
+GROUP(SendingRisksDataRace, "sending-risks-data-race")
+GROUP(StrictLanguageFeatures, "strict-language-features")
+GROUP(StrictMemorySafety, "strict-memory-safety")
+GROUP(StringInterpolationConformance, "string-interpolation-conformance")
+GROUP(TemporaryPointers, "temporary-pointers")
+GROUP(TrailingClosureMatching, "trailing-closure-matching")
+GROUP(UnknownWarningGroup, "unknown-warning-group")
+GROUP(CompilationCaching, "compilation-caching")
+GROUP(WeakMutability, "weak-mutability")
+
+GROUP(PerformanceHints, "performance-hints")
+GROUP(ReturnTypeImplicitCopy, "return-type-implicit-copy")
+GROUP_LINK(PerformanceHints, ReturnTypeImplicitCopy)
+GROUP(ExistentialType, "existential-type")
+GROUP_LINK(PerformanceHints, ExistentialType)
 
 #define UNDEFINE_DIAGNOSTIC_GROUPS_MACROS
 #include "swift/AST/DefineDiagnosticGroupsMacros.h"
diff --git a/include/swift/AST/DiagnosticKind.h b/include/swift/AST/DiagnosticKind.h
new file mode 100644
index 0000000000000..f973a6ea7d8e8
--- /dev/null
+++ b/include/swift/AST/DiagnosticKind.h
@@ -0,0 +1,35 @@
+//===-- AST/DiagnosticKind.h ------------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_AST_DIAGNOSTIC_KIND_H
+#define SWIFT_AST_DIAGNOSTIC_KIND_H
+
+/// `DiagnosticKind.h` is imported into Swift. Be *very* careful with what you
+/// include here and keep these includes minimal!
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
+#include "swift/Basic/SwiftBridging.h"
+#include <stdint.h>
+
+namespace swift {
+
+/// Describes the kind of diagnostic.
+enum class ENUM_EXTENSIBILITY_ATTR(open) DiagnosticKind : uint8_t {
+  Error SWIFT_NAME("error"),
+  Warning SWIFT_NAME("warning"),
+  Remark SWIFT_NAME("remark"),
+  Note SWIFT_NAME("note")
+};
+
+} // namespace swift
+
+#endif // SWIFT_AST_DIAGNOSTIC_KIND_H
diff --git a/include/swift/AST/DiagnosticList.h b/include/swift/AST/DiagnosticList.h
index a360593df617d..06d64ce6278ad 100644
--- a/include/swift/AST/DiagnosticList.h
+++ b/include/swift/AST/DiagnosticList.h
@@ -17,8 +17,12 @@
 #ifndef SWIFT_DIAGNOSTICLIST_H
 #define SWIFT_DIAGNOSTICLIST_H
 
-#include <cstdint>
-#include <type_traits>
+/// `DiagnosticList.h` is imported into Swift. Be *very* careful with what you
+/// include here and keep these includes minimal!
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
+#include "swift/Basic/SwiftBridging.h"
+#include <stdint.h>
 
 namespace swift {
 
@@ -26,7 +30,7 @@ namespace swift {
 ///
 /// Each of the diagnostics described in Diagnostics.def has an entry in
 /// this enumeration type that uniquely identifies it.
-enum class DiagID : uint32_t {
+enum class ENUM_EXTENSIBILITY_ATTR(open) DiagID : uint32_t {
 #define DIAG(KIND, ID, Group, Options, Text, Signature) ID,
 #include "swift/AST/DiagnosticsAll.def"
   NumDiagsHandle
@@ -34,10 +38,9 @@ enum class DiagID : uint32_t {
 static_assert(static_cast<uint32_t>(swift::DiagID::invalid_diagnostic) == 0,
               "0 is not the invalid diagnostic ID");
 
-constexpr auto NumDiagIDs =
-    static_cast<std::underlying_type_t<DiagID>>(DiagID::NumDiagsHandle);
+constexpr auto NumDiagIDs = static_cast<uint32_t>(DiagID::NumDiagsHandle);
 
-enum class FixItID : uint32_t {
+enum class ENUM_EXTENSIBILITY_ATTR(open) FixItID : uint32_t {
 #define DIAG(KIND, ID, Group, Options, Text, Signature)
 #define FIXIT(ID, Text, Signature) ID,
 #include "swift/AST/DiagnosticsAll.def"
diff --git a/include/swift/AST/DiagnosticsClangImporter.def b/include/swift/AST/DiagnosticsClangImporter.def
index d6f27a807cbcb..2cf1d185f14a9 100644
--- a/include/swift/AST/DiagnosticsClangImporter.def
+++ b/include/swift/AST/DiagnosticsClangImporter.def
@@ -51,10 +51,10 @@ ERROR(emit_pcm_error,Fatal,
 ERROR(dump_pcm_error,Fatal,
    "failed to dump precompiled module '%0'", (StringRef))
 
-WARNING(invalid_swift_name_method,none,
+GROUPED_WARNING(invalid_swift_name_method, ClangDeclarationImport, none,
   "too %select{few|many}0 parameters in swift_name attribute (expected %1; "
   "got %2)", (bool, unsigned, unsigned))
-WARNING(invalid_swift_name_for_decl,none,
+GROUPED_WARNING(invalid_swift_name_for_decl, ClangDeclarationImport, none,
   "custom Swift name '%0' ignored because it is not valid for %kindonly1; "
   "imported as %1 instead",
   (StringRef, ValueDecl *))
@@ -67,20 +67,25 @@ ERROR(swift_name_protocol_static, none, "swift_name cannot be used to define "
 ERROR(swift_name_no_prototype, none,
       "swift_name cannot be used on a non-prototyped function declaration", ())
 
-WARNING(inconsistent_swift_name,none,
+GROUPED_WARNING(inconsistent_swift_name, ClangDeclarationImport, none,
         "inconsistent Swift name for Objective-C %select{method|property}0 "
         "'%1' in '%2' (%3 in '%4' vs. %5 in '%6')",
         (bool, StringRef, StringRef, DeclName, StringRef, DeclName,
          StringRef))
 
-WARNING(swift_name_circular_context_import,none,
+WARNING(swift_name_attr_ignored, none,
+        "ignoring swift_name attribute %0; swift_name attributes have no "
+        "effect on method overrides",
+        (StringRef))
+
+GROUPED_WARNING(swift_name_circular_context_import, ClangDeclarationImport, none,
         "cycle detected while resolving '%0' in swift_name attribute for '%1'",
         (StringRef, StringRef))
 NOTE(swift_name_circular_context_import_other,none,
      "while resolving '%0' in swift_name attribute for '%1'",
      (StringRef, StringRef))
 
-WARNING(unresolvable_clang_decl,none,
+GROUPED_WARNING(unresolvable_clang_decl, ClangDeclarationImport, none,
         "imported declaration '%0' could not be mapped to '%1'",
         (StringRef, StringRef))
 
@@ -88,38 +93,41 @@ NOTE(unresolvable_clang_decl_is_a_framework_bug,none,
      "please report this issue to the owners of '%0'",
      (StringRef))
 
-WARNING(clang_swift_attr_unhandled,none,
+GROUPED_WARNING(clang_swift_attr_unhandled, ClangDeclarationImport, none,
         "ignoring unknown Swift attribute or modifier '%0'", (StringRef))
 
-WARNING(clang_error_code_must_be_sendable,none,
-        "cannot make error code type '%0' non-sendable because Swift errors "
+GROUPED_WARNING(clang_error_code_must_be_sendable, ClangDeclarationImport, none,
+        "cannot make error code type '%0' non-Sendable because Swift errors "
         "are always sendable", (StringRef))
 
-WARNING(clang_ignored_sendable_attr,none,
+GROUPED_WARNING(clang_ignored_sendable_attr, ClangDeclarationImport, none,
         "cannot make type %0 sendable because '@Sendable' and '& Sendable' "
         "cannot be added to it",
         (Type))
-NOTE(clang_param_should_be_implicitly_sendable,none,
-     "parameter should be implicitly 'Sendable' because it is a completion "
-     "handler", ())
+
+GROUPED_WARNING(warn_clang_ignored_bounds_on_self, ClangDeclarationImport, none,
+                "bounds attribute '%0' ignored on parameter mapped to 'self'",
+                (StringRef))
+NOTE(note_swift_name_instance_method, none,
+     "swift_name maps free function to instance method here", ())
 
 WARNING(implicit_bridging_header_imported_from_module,none,
         "implicit import of bridging header '%0' via module %1 "
         "is deprecated and will be removed in a later version of Swift",
         (StringRef, Identifier))
 
-WARNING(import_multiple_mainactor_attr,none,
+GROUPED_WARNING(import_multiple_mainactor_attr, ClangDeclarationImport, none,
       "this attribute for global actor '%0' is invalid; the declaration already has attribute for global actor '%1'",
       (StringRef, StringRef))
 
-WARNING(contradicting_mutation_attrs,none,
+GROUPED_WARNING(contradicting_mutation_attrs, ClangDeclarationImport, none,
         "attribute '%0' is ignored when combined with attribute '%1'",
         (StringRef, StringRef))
 
-WARNING(nonmutating_without_const,none,
+GROUPED_WARNING(nonmutating_without_const, ClangDeclarationImport, none,
         "attribute 'nonmutating' has no effect on non-const method", ())
 
-WARNING(nonmutating_without_mutable_fields,none,
+GROUPED_WARNING(nonmutating_without_mutable_fields, ClangDeclarationImport, none,
         "attribute 'nonmutating' has no effect without any mutable fields", ())
 
 ERROR(module_map_not_found, none, "module map file '%0' not found", (StringRef))
@@ -135,7 +143,7 @@ WARNING(libstdcxx_modulemap_not_found, none,
         "module map for libstdc++ not found for '%0'; C++ stdlib may be unavailable",
         (StringRef))
 
-WARNING(api_pattern_attr_ignored, none,
+GROUPED_WARNING(api_pattern_attr_ignored, ClangDeclarationImport, none,
         "'%0' Swift attribute ignored on type '%1': type is not copyable or destructible",
         (StringRef, StringRef))
 
@@ -226,7 +234,7 @@ ERROR(private_fileid_attr_repeated, none,
  NOTE(private_fileid_attr_here, none,
      "SWIFT_PRIVATE_FILEID annotation found here", ())
 
- WARNING(private_fileid_attr_format_invalid, none,
+ GROUPED_WARNING(private_fileid_attr_format_invalid, ClangDeclarationImport, none,
      "SWIFT_PRIVATE_FILEID annotation on '%0' does not have a valid file ID",
      (StringRef))
  REMARK(private_fileid_attr_format_specification, none,
@@ -259,15 +267,18 @@ ERROR(foreign_reference_types_invalid_retain_release, none,
 
 ERROR(foreign_reference_types_retain_non_void_or_self_return_type, none,
       "specified retain function '%0' is invalid; "
-      "retain function must have 'void' or parameter return type",
+      "retain function must either return have 'void', the reference count as an integer, or the parameter type",
       (StringRef))
 ERROR(foreign_reference_types_release_non_void_return_type, none,
       "specified release function '%0' is invalid; "
-      "release function must have 'void' return type",
+      "release function must either return 'void' or the reference count as an integer",
       (StringRef))
 ERROR(foreign_reference_types_retain_release_not_a_function_decl, none,
       "specified %select{retain|release}0 function '%1' is not a function",
       (bool, StringRef))
+ERROR(foreign_reference_types_retain_release_not_an_instance_function, none,
+      "specified %select{retain|release}0 function '%1' is a static function; expected an instance function",
+      (bool, StringRef))
 ERROR(conforms_to_missing_dot, none,
       "expected module name and protocol name separated by '.' in protocol "
       "conformance; '%0' is invalid",
@@ -282,7 +293,8 @@ ERROR(conforms_to_ambiguous,none,
       "ambiguous reference to protocol '%0' in specified protocol conformance; module '%1' contains multiple protocols named '%0'", (StringRef, StringRef))
 
 ERROR(conforms_to_not_protocol,none,
-      "%0 %1 referenced in protocol conformance '%2' is not a protocol", (DescriptiveDeclKind, ValueDecl *, StringRef))
+      "%kind0 referenced in protocol conformance '%1' is not a protocol",
+      (const ValueDecl *, StringRef))
 
 ERROR(failed_base_method_call_synthesis,none,
       "failed to synthesize call to the base method %0 of type %0",
@@ -293,21 +305,16 @@ ERROR(both_returns_retained_returns_unretained, none,
       "SWIFT_RETURNS_UNRETAINED",
       (const clang::NamedDecl *))
 
-ERROR(returns_retained_or_returns_unretained_for_non_cxx_frt_values, none,
-      "%0 cannot be annotated with either SWIFT_RETURNS_RETAINED or "
+ERROR(redundant_conformance_protocol,none,
+     "redundant conformance of %0 to protocol '%1'", (Type, StringRef))
+
+WARNING(returns_retained_or_returns_unretained_for_non_cxx_frt_values, none,
+      "%0 should not be annotated with SWIFT_RETURNS_RETAINED or "
       "SWIFT_RETURNS_UNRETAINED because it is not returning "
       "a SWIFT_SHARED_REFERENCE type",
       (const clang::NamedDecl *))
 
-// TODO: In the next C++ interop version, convert this warning into an error and
-// stop importing unannotated C++ APIs that return SWIFT_SHARED_REFERENCE.
-// rdar://138806722
-WARNING(no_returns_retained_returns_unretained, none,
-        "%0 should be annotated with either SWIFT_RETURNS_RETAINED or "
-        "SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE",
-        (const clang::NamedDecl *))
-
-WARNING(returns_retained_returns_unretained_on_overloaded_operator, none,
+GROUPED_WARNING(returns_retained_returns_unretained_on_overloaded_operator,  ClangDeclarationImport, none,
         "SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED is not supported "
         "yet for overloaded C++ %0. Overloaded C++ operators always "
         "return "
@@ -318,7 +325,7 @@ WARNING(returns_retained_returns_unretained_on_overloaded_operator, none,
 // stop importing C++ types that inherit from SWIFT_SHARED_REFERENCE if the
 // Swift compiler cannot find unique retain/release functions.
 // rdar://145194375
-WARNING(cant_infer_frt_in_cxx_inheritance, none,
+GROUPED_WARNING(cant_infer_frt_in_cxx_inheritance, ClangDeclarationImport, none,
         "unable to infer SWIFT_SHARED_REFERENCE for %0, although one of its "
         "transitive base types is marked as SWIFT_SHARED_REFERENCE",
         (const clang::NamedDecl *))
@@ -351,8 +358,12 @@ NOTE(forward_declared_protocol_clashes_with_imported_objc_Swift_protocol, none,
      "its name conflicts with a %1 in module %2",
      (const clang::NamedDecl*, StringRef, StringRef))
 
-WARNING(return_escapable_with_lifetimebound, none, "the returned type '%0' is annotated as escapable; it cannot have lifetime dependencies", (StringRef))
-WARNING(return_nonescapable_without_lifetimebound, none, "the returned type '%0' is annotated as non-escapable; its lifetime dependencies must be annotated", (StringRef))
+GROUPED_WARNING(return_escapable_with_lifetimebound,  ClangDeclarationImport, none,
+     "the returned type '%0' is annotated as escapable; it cannot have lifetime dependencies",
+     (StringRef))
+GROUPED_WARNING(return_nonescapable_without_lifetimebound, ClangDeclarationImport, none,
+     "the returned type '%0' is annotated as non-escapable; its lifetime dependencies must be annotated",
+     (StringRef))
 
 ERROR(unknown_template_parameter,none,
   "template parameter '%0' does not exist", (StringRef))
@@ -373,5 +384,9 @@ NOTE(ptr_to_nonescapable,none,
      "pointer to non-escapable type %0 cannot be imported",
      (const clang::Type*))
 
+NOTE(nonescapable_field_of_escapable, none,
+     "escapable record %0 cannot have non-escapable field '%1'",
+     (const clang::NamedDecl *, StringRef))
+
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"
diff --git a/include/swift/AST/DiagnosticsCommon.def b/include/swift/AST/DiagnosticsCommon.def
index 14c2e9b76cc31..ffa723d4d2c10 100644
--- a/include/swift/AST/DiagnosticsCommon.def
+++ b/include/swift/AST/DiagnosticsCommon.def
@@ -23,6 +23,13 @@
 ERROR(invalid_diagnostic,none,
       "INTERNAL ERROR: this diagnostic should not be produced", ())
 
+NOTE(kind_declname_declared_here,none,
+     "%0 %1 declared here", (DescriptiveDeclKind, DeclName))
+NOTE(decl_declared_here_with_kind,none,
+     "%kind0 declared here", (const Decl *))
+NOTE(through_decl_declared_here_with_kind,none,
+     "through %kind0 declared here", (const Decl *))
+
 ERROR(not_implemented,none,
       "INTERNAL ERROR: feature not implemented: %0", (StringRef))
 
@@ -87,7 +94,7 @@ ERROR(require_literal_initializer_for_literal,none,
       "_const let should be initialized with a literal value", ())
       
 ERROR(require_const_initializer_for_const,none,
-      "@const value should be initialized with a compile-time value", ())
+      "'@const' value should be initialized with a compile-time value", ())
 
 ERROR(require_const_arg_for_parameter,none,
       "expected a compile-time value argument for a '@const' parameter", ())
@@ -176,9 +183,6 @@ ERROR(circular_enum_inheritance,none,
 ERROR(circular_protocol_def,none,
       "protocol %0 refines itself", (Identifier))
 
-NOTE(kind_declname_declared_here,none,
-     "%0 %1 declared here", (DescriptiveDeclKind, DeclName))
-
 WARNING(warn_property_wrapper_module_scope,none,
         "ignoring associated type %0 in favor of module-scoped property "
         "wrapper %0; please qualify the reference with %1",
@@ -212,6 +216,9 @@ ERROR(scanner_find_cycle, none,
 NOTE(scanner_find_cycle_swift_overlay_path, none,
      "Swift Overlay dependency of '%0' on '%1' via Clang module dependency: '%2'", (StringRef, StringRef, StringRef))
 
+NOTE(scanner_cycle_source_target_shadow_module, none,
+     "source target '%0' shadowing a%select{ |n SDK }2Swift module with the same name at: '%1'", (StringRef, StringRef, bool))
+
 ERROR(scanner_arguments_invalid, none,
       "dependencies scanner cannot be configured with arguments: '%0'", (StringRef))
 
@@ -251,8 +258,10 @@ REMARK(remark_scanner_invalidate_missing_cas, none,
 // MARK: custom attribute diagnostics
 //------------------------------------------------------------------------------
 
-ERROR(unknown_attribute,none,
+ERROR(unknown_attr_name,none,
       "unknown attribute '%0'", (StringRef))
+ERROR(unknown_type_attr,none,
+      "unknown %kind0", (const TypeAttribute *))
 
 //------------------------------------------------------------------------------
 // MARK: macro diagnostics
@@ -270,6 +279,13 @@ ERROR(macro_experimental,none,
 ERROR(lookup_outputs_dont_match,none,
 "Unqualified lookup output from ASTScope and SwiftLexicalLookup don't match", ())
 
+//------------------------------------------------------------------------------
+// MARK: Accessor diagnostics
+//------------------------------------------------------------------------------
+
+ERROR(accessor_not_supported_in_decl,none,
+      "%0 is supported only on a struct or enum", (StringRef))      
+
 //------------------------------------------------------------------------------
 // MARK: bridged diagnostics
 //------------------------------------------------------------------------------
diff --git a/include/swift/AST/DiagnosticsCommon.h b/include/swift/AST/DiagnosticsCommon.h
index 80d0c725ffe46..afde6bf6820f3 100644
--- a/include/swift/AST/DiagnosticsCommon.h
+++ b/include/swift/AST/DiagnosticsCommon.h
@@ -24,6 +24,13 @@
 #include "swift/Config.h"
 
 namespace swift {
+  class AccessorDecl;
+  class ConstructorDecl;
+  class MacroDecl;
+  class SubscriptDecl;
+  class SwitchStmt;
+  class TypeAliasDecl;
+
   template<typename ...ArgTypes>
   struct Diag;
 
@@ -48,6 +55,7 @@ namespace swift {
   } // end namespace detail
 
   enum class StaticSpellingKind : uint8_t;
+  enum class ForeignLanguage : uint8_t;
 
   namespace diag {
 
diff --git a/include/swift/AST/DiagnosticsDriver.def b/include/swift/AST/DiagnosticsDriver.def
index c98ad2af6939c..957a626fac49b 100644
--- a/include/swift/AST/DiagnosticsDriver.def
+++ b/include/swift/AST/DiagnosticsDriver.def
@@ -114,9 +114,6 @@ WARNING(warn_opt_remark_disabled, none,
         "requires a single compiler invocation: consider enabling the "
         "-whole-module-optimization flag", ())
 
-WARNING(warn_ignoring_batch_mode,none,
-"ignoring '-enable-batch-mode' because '%0' was also specified", (StringRef))
-
 WARNING(warn_ignoring_wmo, none,
         "ignoring '-wmo' because '-dump-ast' was also specified", ())
 
diff --git a/include/swift/AST/DiagnosticsFrontend.def b/include/swift/AST/DiagnosticsFrontend.def
index 41736350078fa..c2ebf1b73e9bb 100644
--- a/include/swift/AST/DiagnosticsFrontend.def
+++ b/include/swift/AST/DiagnosticsFrontend.def
@@ -59,9 +59,9 @@ GROUPED_WARNING(cannot_disable_feature_with_mode, StrictLanguageFeatures, none,
                 "'%0' argument '%1' cannot specify a mode",
                 (StringRef, StringRef))
 
-GROUPED_WARNING(feature_does_not_support_adoption_mode, StrictLanguageFeatures,
+GROUPED_WARNING(feature_does_not_support_migration_mode, StrictLanguageFeatures,
                 none,
-                "feature '%0' does not support adoption mode",
+                "feature '%0' does not support migration mode",
                 (StringRef))
 
 ERROR(error_unknown_library_level, none,
@@ -126,8 +126,6 @@ WARNING(warning_locale_path_not_found,none,
       "translation is disabled", (StringRef))
 WARNING(warning_cannot_find_locale_file,none,
       "cannot find translations for '%0' at '%1': no such file", (StringRef, StringRef))
-WARNING(warning_cannot_multithread_batch_mode,none,
-      "ignoring -num-threads argument; cannot multithread batch mode", ())
 ERROR(error_cannot_explicit_interface_build_in_mode,none,
       "'-explicit-interface-module-build' only supported when building a module from interface ('-compile-module-from-interface' or '-typecheck-module-from-interface')'", ())
 ERROR(error_unsupported_option_argument,none,
@@ -158,6 +156,9 @@ ERROR(error_load_resolved_plugin,none,
 NOTE(note_valid_swift_versions, none,
      "valid arguments to '-swift-version' are %0", (StringRef))
 
+ERROR(error_module_interface_requires_language_mode,none,
+      "emitting module interface files requires '-language-mode'", ())
+
 ERROR(error_mode_cannot_emit_dependencies,none,
       "this mode does not support emitting dependency files", ())
 ERROR(error_mode_cannot_emit_reference_dependencies,none,
@@ -193,10 +194,12 @@ ERROR(cannot_emit_ir_skipping_function_bodies,none,
 WARNING(emit_reference_dependencies_without_primary_file,none,
         "ignoring -emit-reference-dependencies (requires -primary-file)", ())
 
+WARNING(ignoring_option_obsolete,none,
+        "ignoring '%0'; this option is obsolete", (StringRef))
 WARNING(ignoring_option_requires_option,none,
         "ignoring %0 (requires %1)", (StringRef, StringRef))
-WARNING(warn_ignore_option_overriden_by,none,
-        "ignoring %0 (overriden by %1)", (StringRef, StringRef))
+WARNING(warn_ignore_option_overridden_by,none,
+        "ignoring %0 (overridden by %1)", (StringRef, StringRef))
 
 WARNING(warn_implicit_concurrency_import_failed,none,
         "unable to perform implicit import of \"_Concurrency\" module: no such module found", ())
@@ -211,6 +214,9 @@ ERROR(error_stdlib_module_name,none,
       "module name \"%0\" is reserved for the standard library"
       "%select{|; use -module-name flag to specify an alternate name}1",
       (StringRef, bool))
+WARNING(warn_multiple_module_inputs_same_name,none,
+        "multiple Swift module file inputs with identifier \"%0\": replacing '%1' with '%2'",
+        (StringRef, StringRef, StringRef))
 
 ERROR(error_bad_export_as_name,none,
       "export-as name \"%0\" is not a valid identifier",
@@ -357,16 +363,8 @@ ERROR(explicit_swift_module_map_missing,none,
       (StringRef))
 
 ERROR(explicit_swift_module_map_corrupted,none,
-      "explicit Swift module map from %0 is malformed",
-      (StringRef))
-
-ERROR(placeholder_dependency_module_map_missing,none,
-      "cannot open Swift placeholder dependency module map from %0",
-      (StringRef))
-
-ERROR(placeholder_dependency_module_map_corrupted,none,
-      "Swift placeholder dependency module map from %0 is malformed",
-      (StringRef))
+      "explicit Swift module map from %0 is malformed: %1",
+      (StringRef, StringRef))
 
 ERROR(const_extract_protocol_list_input_file_missing,none,
       "cannot open constant extraction protocol list input file from %0",
@@ -517,23 +515,35 @@ REMARK(matching_output_produced,none,
       "produced matching output file '%0' for deterministic check: hash '%1'", (StringRef, StringRef))
 
 // Caching related diagnostics
-ERROR(error_caching_no_cas_fs, none,
-    "caching is enabled without -cas-fs option, input is not immutable", ())
+GROUPED_ERROR(error_caching_no_cas_fs, CompilationCaching, none,
+    "caching is enabled without CAS file-system options, input is not immutable", ())
 ERROR(error_prefix_mapping, none, "cannot create scanner prefix mapping: '%0'", (StringRef))
 
 REMARK(replay_output, none, "replay output file '%0': key '%1'", (StringRef, StringRef))
 REMARK(output_cache_miss, none, "cache miss for input file '%0': key '%1'", (StringRef, StringRef))
 
 // CAS related diagnostics
-ERROR(error_cas, none, "CAS error encountered: %0", (StringRef))
-WARNING(cache_replay_failed, none, "cache replay failed: %0", (StringRef))
+GROUPED_ERROR(error_invalid_cas_id, CompilationCaching, none, "CAS cannot parse id '%0': %1", (StringRef, StringRef))
+GROUPED_ERROR(error_cas, CompilationCaching, none, "CAS error encountered during %0: %1", (StringRef, StringRef))
+GROUPED_ERROR(error_cas_fs_creation, CompilationCaching, none, "cannot create CAS filesystem: %0", (StringRef))
+GROUPED_ERROR(error_cache_key_creation, CompilationCaching, none, "cannot create cache key for compilation %0: %1", (StringRef, StringRef))
+GROUPED_ERROR(error_cas_file_ref, CompilationCaching, none, "cannot load file %0 from CAS filesystem", (StringRef))
+GROUPED_ERROR(error_cas_conflict_options, CompilationCaching, none, "cannot setup CAS due to conflicting '-cas-*' options", ())
+GROUPED_ERROR(error_cas_initialization, CompilationCaching, none, "CAS cannot be initialized from the specified '-cas-*' options: %0", (StringRef))
+GROUPED_ERROR(error_cas_malformed_input, CompilationCaching, none, "CAS input '%0' is malformed: %1", (StringRef, StringRef))
+GROUPED_WARNING(cache_replay_failed, CompilationCaching, none, "cache replay failed: %0", (StringRef))
+
+GROUPED_ERROR(error_failed_cached_diag, CompilationCaching, none, "failed to serialize cached diagnostics: %0", (StringRef))
+GROUPED_ERROR(error_replay_cached_diag, CompilationCaching, none, "failed to replay cached diagnostics: %0", (StringRef))
+
+GROUPED_ERROR(error_load_input_from_cas, CompilationCaching, none, "failed to load input '%0' from CAS", (StringRef))
 
-ERROR(error_failed_cached_diag, none, "failed to serialize cached diagnostics: %0", (StringRef))
-ERROR(error_replay_cached_diag, none, "failed to replay cached diagnostics: %0", (StringRef))
+GROUPED_ERROR(error_wrong_input_num_for_input_file_key, CompilationCaching, none, "-input-file-key only support one input file", ())
 
-ERROR(error_load_input_from_cas, none, "failed to load input '%0' from CAS", (StringRef))
+ERROR(error_gen_reproducer_not_caching, none, "-gen-reproducer only supports swift caching (-cache-compile-job)", ())
+ERROR(error_cannot_create_reproducer_dir, none, "failed to create reproducer director '%0': %1", (StringRef, StringRef))
 
-ERROR(error_wrong_input_num_for_input_file_key, none, "-input-file-key only support one input file", ())
+NOTE(note_reproducer, none, "reproducer is available at: %0", (StringRef))
 
 // Dependency Verifier Diagnostics
 ERROR(missing_member_dependency,none,
@@ -558,9 +568,6 @@ WARNING(module_incompatible_with_skip_function_bodies,none,
         "-experimental-skip-*-function-bodies* flags; they have "
         "been automatically disabled", (StringRef))
 
-WARNING(access_notes_file_io_error,none,
-        "ignored access notes file at '%0' because it cannot be read: %1",
-        (StringRef, StringRef))
 WARNING(error_in_access_notes_file,none,
         "ignored access notes file because it cannot be parsed: %0",
         (StringRef))
@@ -594,12 +601,17 @@ ERROR(objc_with_embedded,none,
       "Objective-C interoperability cannot be enabled with embedded Swift.", ())
 ERROR(no_allocations_without_embedded,none,
       "-no-allocations is only applicable with embedded Swift.", ())
+ERROR(min_ptr_value_without_embedded,none,
+      "-min-valid-pointer-value is only applicable with embedded Swift.", ())
 ERROR(no_swift_sources_with_embedded,none,
       "embedded swift cannot be enabled in a compiler built without Swift sources", ())
 
 ERROR(package_cmo_requires_library_evolution, none,
         "Library evolution must be enabled for Package CMO", ())
 
+WARNING(internal_bridging_header_without_library_evolution,none,
+        "using internal bridging headers without library evolution can cause instability", ())
+
 ERROR(experimental_not_supported_in_production,none,
       "experimental feature '%0' cannot be enabled in production compiler",
       (StringRef))
@@ -618,5 +630,17 @@ ERROR(ast_format_requires_dump_ast,none,
 ERROR(unknown_dump_ast_format,none,
       "unknown format '%0' requested with '-dump-ast-format'", (StringRef))
 
+ERROR(dependency_scan_unexpected_variant, none,
+      "unexpected variant during dependency scanning on module '%0'", (StringRef))
+NOTE(dependency_scan_unexpected_variant_context_hash_note, none,
+     "first module context hash: '%0', second module context hash: '%1'", (StringRef, StringRef))
+NOTE(dependency_scan_unexpected_variant_module_map_note, none,
+     "first module module map: '%0', second module module map: '%1'", (StringRef, StringRef))
+NOTE(dependency_scan_unexpected_variant_extra_arg_note, none,
+     "%select{first|second}0 module command-line has extra argument: '%1'", (bool, StringRef))
+
+ERROR(bridging_header_and_pch_internal_mismatch,none,
+      "bridging header and precompiled header options mismatch on internal vs. public import", ())
+
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"
diff --git a/include/swift/AST/DiagnosticsIRGen.def b/include/swift/AST/DiagnosticsIRGen.def
index ad85f2f9df6e7..e01cd868d5827 100644
--- a/include/swift/AST/DiagnosticsIRGen.def
+++ b/include/swift/AST/DiagnosticsIRGen.def
@@ -42,12 +42,12 @@ ERROR(no_input_files_for_mt,none,
       "no swift input files for multi-threaded compilation", ())
 
 ERROR(alignment_dynamic_type_layout_unsupported,none,
-      "@_alignment is not supported on types with dynamic layout", ())
+      "'@_alignment' is not supported on types with dynamic layout", ())
 ERROR(alignment_less_than_natural,none,
-      "@_alignment cannot decrease alignment below natural alignment of %0",
+      "'@_alignment' cannot decrease alignment below natural alignment of %0",
       (unsigned))
 ERROR(alignment_more_than_maximum,none,
-      "@_alignment cannot increase alignment above maximum alignment of %0",
+      "'@_alignment' cannot increase alignment above maximum alignment of %0",
       (unsigned))
       
 ERROR(temporary_allocation_size_negative,none,
@@ -80,5 +80,37 @@ ERROR(attr_objc_implementation_resilient_property_deployment_target, none,
 ERROR(unable_to_load_pass_plugin,none,
       "unable to load plugin '%0': '%1'", (StringRef, StringRef))
 
+ERROR(failed_emit_copy, none,
+      "failed to copy %0; did you mean to import %0 as ~Copyable?",
+      (const clang::NamedDecl *))
+
+NOTE(use_requires_expression, none,
+     "use 'requires' (since C++20) to specify the constraints under which the "
+     "copy "
+     "constructor is available",
+     ())
+
+NOTE(annotate_copyable_if, none,
+     "annotate a type with 'SWIFT_COPYABLE_IF(<T>)' in C++ to specify "
+     "that the type is Copyable if <T> is Copyable",
+     ())
+
+NOTE(annotate_non_copyable, none,
+     "annotate a type with 'SWIFT_NONCOPYABLE' in C++ to import it as "
+     "~Copyable",
+     ())
+
+NOTE(maybe_missing_annotation, none,
+     "one of the types that %0 depends on may need a 'requires' clause (since "
+     "C++20) in the copy constructor, a 'SWIFT_COPYABLE_IF' annotation or a "
+     "'SWIFT_NONCOPYABLE' annotation'",
+     (const clang::NamedDecl *))
+
+NOTE(maybe_missing_parameter, none,
+     "the %select{'requires' clause on the copy constructor "
+     "of|'SWIFT_COPYABLE_IF' annotation on}0 %1 may be missing a "
+     "%select{constraint|parameter}0",
+     (bool, const clang::NamedDecl *))
+
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"
diff --git a/include/swift/AST/DiagnosticsModuleDiffer.def b/include/swift/AST/DiagnosticsModuleDiffer.def
index 7e295ba80e805..d74b6d349c201 100644
--- a/include/swift/AST/DiagnosticsModuleDiffer.def
+++ b/include/swift/AST/DiagnosticsModuleDiffer.def
@@ -66,7 +66,7 @@ ERROR(optional_req_changed,APIDigesterBreakage,"%0 is %select{now|no longer}1 an
 
 ERROR(no_longer_open,APIDigesterBreakage,"%0 is no longer open for subclassing", (StringRef))
 
-ERROR(func_type_escaping_changed,APIDigesterBreakage,"%0 has %select{removed|added}2 @escaping in %1", (StringRef, StringRef, bool))
+ERROR(func_type_escaping_changed,APIDigesterBreakage,"%0 has %select{removed|added}2 '@escaping' in %1", (StringRef, StringRef, bool))
 
 ERROR(func_self_access_change,APIDigesterBreakage,"%0 has self access kind changing from %1 to %2", (StringRef, StringRef, StringRef))
 
@@ -78,7 +78,7 @@ ERROR(decl_new_witness_table_entry,APIDigesterBreakage,"%0 now requires%select{|
 
 ERROR(class_member_moved_to_extension,APIDigesterBreakage,"Non-final class member %0 is moved to extension", (StringRef))
 
-WARNING(new_decl_without_intro,APIDigesterBreakage,"%0 is a new API without @available attribute", (StringRef))
+WARNING(new_decl_without_intro,APIDigesterBreakage,"%0 is a new API without '@available'", (StringRef))
 
 ERROR(objc_name_change,APIDigesterBreakage,"%0 has ObjC name change from %1 to %2", (StringRef, StringRef, StringRef))
 
diff --git a/include/swift/AST/DiagnosticsParse.def b/include/swift/AST/DiagnosticsParse.def
index 6d3f9b400f73b..d6379e0fe37df 100644
--- a/include/swift/AST/DiagnosticsParse.def
+++ b/include/swift/AST/DiagnosticsParse.def
@@ -62,7 +62,7 @@ ERROR(pound_diagnostic_expected_string,none,
       "expected string literal in %select{#warning|#error}0 directive",(bool))
 ERROR(pound_diagnostic_expected,none,
       "expected '%0' in %select{#warning|#error}1 directive",(StringRef,bool))
-ERROR(pound_diagnostic_expected_parens,none,
+ERROR(pound_diagnostic_expected_parens,PointsToFirstBadToken,
       "%select{#warning|#error}0 directive requires parentheses",(bool))
 ERROR(pound_diagnostic_interpolation,none,
       "string interpolation is not allowed in %select{#warning|#error}0 directives",(bool))
@@ -229,8 +229,8 @@ ERROR(disallowed_var_multiple_getset,none,
       "'var' declarations with multiple variables cannot have explicit"
       " getters/setters", ())
 ERROR(stub_decl_cannot_have_body,none,
-      "stub %0 cannot have body",
-      (DescriptiveDeclKind))
+      "stub %kindonly0 cannot have body",
+      (const Decl *))
 
 ERROR(disallowed_init,none,
       "initial value is not allowed here", ())
@@ -303,6 +303,10 @@ ERROR(missing_reading_accessor,none,
       "%select{variable|subscript}0 with %1 must also have "
       "a getter, addressor, or 'read' accessor",
       (unsigned, StringRef))
+ERROR(missing_borrow_accessor,none,
+      "%select{variable|subscript}0 with %1 must also have "
+      "a 'borrow' accessor, getter, addressor or 'read' accessor",
+      (unsigned, StringRef))
 ERROR(observing_accessor_conflicts_with_accessor,none,
       "%select{'willSet'|'didSet'}0 cannot be provided together with %1",
       (unsigned, StringRef))
@@ -313,6 +317,9 @@ ERROR(getset_cannot_be_implied,none,
 ERROR(accessor_requires_coroutine_accessors,none,
       "%0 is only valid when experimental feature coroutine accessors is enabled",
       (StringRef))
+ERROR(accessor_requires_borrow_and_mutate_accessors,none,
+      "%0 requires '-enable-experimental-feature BorrowAndMutateAccessors'",
+      (StringRef))
 
 // Import
 ERROR(decl_expected_module_name,none,
@@ -497,7 +504,7 @@ ERROR(expected_precedencegroup_relation,none,
 ERROR(expected_sil_keyword,none,
       "expected SIL keyword", ())
 ERROR(inout_not_attribute, none,
-      "@inout is no longer an attribute", ())
+      "'inout' is no longer an attribute", ())
 ERROR(only_allowed_in_sil,none,
       "'%0' only allowed in SIL modules", (StringRef))
 ERROR(expected_sil_type,none,
@@ -520,7 +527,7 @@ ERROR(silfunc_and_silarg_have_incompatible_sil_value_ownership,none,
       "Function type specifies: '@%0'. SIL argument specifies: '@%1'.",
       (StringRef, StringRef))
 ERROR(sil_arg_both_lexical_and_eagerMove,none,
-      "Function argument is annotated both @_eagerMove and @_noEagerMove, "
+      "Function argument is annotated both '@_eagerMove' and '@_noEagerMove', "
       "but these are incompatible alternatives", ())
 ERROR(expected_sil_colon,none,
       "expected ':' before %0", (StringRef))
@@ -1484,9 +1491,12 @@ ERROR(multiple_access_level_modifiers,none,
       "multiple incompatible access-level modifiers specified", ())
 NOTE(previous_access_level_modifier,none,
      "previous modifier specified here", ())
-ERROR(mutually_exclusive_attrs,none,
+ERROR(mutually_exclusive_decl_attrs,none,
       "%0 contradicts previous %select{attribute|modifier}2 %1",
       (DeclAttribute, DeclAttribute, bool))
+ERROR(mutually_exclusive_type_attrs,none,
+      "%0 contradicts previous %1",
+      (const TypeAttribute *, const TypeAttribute *))
 ERROR(mutually_exclusive_attr_names,none,
       "'%0' contradicts previous %select{attribute|modifier}2 '%1'",
       (StringRef, StringRef, bool))
@@ -1529,6 +1539,9 @@ ERROR(attr_expected_comma,none,
 ERROR(attr_expected_string_literal,none,
 "expected string literal in '%0' attribute", (StringRef))
 
+ERROR(attr_expected_cname,none,
+      "expected C identifier in '%0' attribute", (StringRef))
+
 ERROR(attr_expected_option_such_as,none,
       "expected '%0' option such as '%1'", (StringRef, StringRef))
 
@@ -1568,6 +1581,11 @@ ERROR(attr_unsupported_on_target, none,
 ERROR(attr_name_unsupported_on_target, none,
       "attribute '%0' is unsupported on target '%1'", (StringRef, StringRef))
 
+// abi attribute
+ERROR(attr_abi_incompatible_kind,none,
+      "cannot use %0 in '@abi'",
+      (DescriptiveDeclKind))
+
 // availability
 ERROR(attr_availability_platform,none,
       "expected platform name or '*' for '%0' attribute", (StringRef))
@@ -1624,14 +1642,14 @@ ERROR(attr_availability_duplicate,none,
 
 // originallyDefinedIn
 ERROR(originally_defined_in_missing_rparen,none,
-      "expected ')' in @_originallyDefinedIn argument list", ())
+      "expected ')' in '@_originallyDefinedIn' argument list", ())
 
 ERROR(originally_defined_in_need_original_module_name,none,
       "expected 'module: \"original\"' in the first argument to "
-      "@_originallyDefinedIn", ())
+      "'@_originallyDefinedIn'", ())
 
 ERROR(originally_defined_in_need_nonempty_module_name,none,
-      "original module name cannot be empty in @_originallyDefinedIn", ())
+      "original module name cannot be empty in '@_originallyDefinedIn'", ())
 
 // backDeploy
 ERROR(attr_back_deploy_expected_before_label,none,
@@ -1662,25 +1680,25 @@ ERROR(convention_attribute_witness_method_expected_protocol,none,
 
 // objc
 ERROR(attr_objc_missing_colon,none,
-      "missing ':' after selector piece in @objc attribute", ())
+      "missing ':' after selector piece in '@objc'", ())
 ERROR(attr_objc_expected_rparen,none,
-      "expected ')' after name for @objc", ())
+      "expected ')' after name for '@objc'", ())
 ERROR(attr_objc_empty_name,none,
-      "expected name within parentheses of @objc attribute", ())
+      "expected name within parentheses of '@objc'", ())
 
 ERROR(attr_dynamic_replacement_expected_rparen,none,
-      "expected ')' after function name for @_dynamicReplacement", ())
+      "expected ')' after function name for '@_dynamicReplacement'", ())
 ERROR(attr_dynamic_replacement_expected_function,none,
-      "expected a function name in @_dynamicReplacement(for:)", ())
+      "expected a function name in '@_dynamicReplacement(for:)'", ())
 ERROR(attr_dynamic_replacement_expected_for,none,
       "expected 'for' in '_dynamicReplacement' attribute", ())
 ERROR(attr_dynamic_replacement_expected_colon,none,
-      "expected ':' after @_dynamicReplacement(for", ())
+      "expected ':' after '@_dynamicReplacement(for'", ())
 
 ERROR(attr_type_eraser_expected_type_name,none,
-      "expected a type name in @_typeEraser()", ())
+      "expected a type name in '@_typeEraser()'", ())
 ERROR(attr_type_eraser_expected_rparen,none,
-      "expected ')' after type name for @_typeEraser", ())
+      "expected ')' after type name for '@_typeEraser'", ())
 
 ERROR(expected_thrown_error_type,none,
       "expected thrown error type after 'throws('", ())
@@ -1697,22 +1715,14 @@ ERROR(attr_isolated_expected_rparen,none,
 ERROR(attr_isolated_expected_kind,none,
       "expected 'any' as the isolation kind", ())
 
-ERROR(attr_execution_expected_lparen,none,
-      "expected '(' after '@execution'",
-      ())
-ERROR(attr_execution_expected_rparen,none,
-      "expected ')' after execution behavior", ())
-ERROR(attr_execution_expected_kind,none,
-      "expected 'concurrent' or 'caller' as the execution behavior", ())
-
 ERROR(attr_private_import_expected_rparen,none,
-      "expected ')' after function name for @_private", ())
+      "expected ')' after function name for '@_private'", ())
 ERROR(attr_private_import_expected_sourcefile, none,
       "expected 'sourceFile' in '_private' attribute", ())
 ERROR(attr_private_import_expected_sourcefile_name,none,
-      "expected a source file name in @_private(sourceFile:)", ())
+      "expected a source file name in '@_private(sourceFile:)'", ())
 ERROR(attr_private_import_expected_colon,none,
-      "expected ':' after @_private(sourceFile", ())
+      "expected ':' after '@_private(sourceFile'", ())
 
 // opened
 ERROR(opened_attribute_expected_lparen,none,
@@ -1746,22 +1756,26 @@ ERROR(attr_warn_unused_result_expected_rparen,none,
 
 // _specialize
 ERROR(attr_specialize_missing_colon,none,
-      "missing ':' after %0 in '_specialize' attribute", (StringRef))
+      "missing ':' after %0 in %select{'_specialize'|'specialized'}1 attribute", (StringRef, bool))
 
 ERROR(attr_specialize_missing_comma,none,
-      "missing ',' in '_specialize' attribute", ())
+      "missing ',' in %select{'_specialize'|'specialized'}0 attribute", (bool))
 
 ERROR(attr_specialize_unknown_parameter_name,none,
-      "unknown parameter %0 in '_specialize attribute'", (StringRef))
+      "unknown parameter %0 in %select{'_specialize'|'specialized'}1 attribute", (StringRef, bool))
+ERROR(attr_specialize_unsupported_parameter_name,none,
+      "unsupported parameter %0 in 'specialized attribute'", (StringRef))
 
 ERROR(attr_specialize_expected_bool_value,none,
-      "expected a boolean true or false value in '_specialize' attribute", ())
+      "expected a boolean true or false value in %select{'_specialize'|'specialized'}0 attribute", (bool))
 
 ERROR(attr_specialize_missing_parameter_label_or_where_clause,none,
       "expected a parameter label or a where clause in '_specialize' attribute", ())
+ERROR(attr_specialized_missing_where_clause,none,
+      "expected a where clause in 'specialized' attribute", ())
 
 ERROR(attr_specialize_parameter_already_defined,none,
-      "parameter '%0' was already defined in '_specialize' attribute", (StringRef))
+      "parameter '%0' was already defined in %select{'_specialize'|'specialized'}1 attribute", (StringRef, bool))
 
 ERROR(attr_specialize_expected_partial_or_full,none,
       "expected 'partial' or 'full' as values of the 'kind' parameter in '_specialize' attribute", ())
@@ -1833,18 +1847,18 @@ ERROR(sil_inst_autodiff_expected_differentiability_witness_kind,PointsToFirstBad
       "'[vjp]', or '[transpose]'", ())
 
 WARNING(warn_attr_unsafe_removed,none,
-        "'%0' attribute has been removed in favor of @preconcurrency",
+        "'%0' attribute has been removed in favor of '@preconcurrency'",
         (StringRef))
 
 // _documentation
 ERROR(documentation_attr_expected_argument,none,
-      "@_documentation attribute expected 'visibility' or 'metadata' argument",
+      "'_documentation' attribute expected 'visibility' or 'metadata' argument",
       ())
 ERROR(documentation_attr_unknown_argument,none,
       "unknown argument '%0', expected 'visibility' or 'metadata'",
       (StringRef))
 ERROR(documentation_attr_expected_access_level,none,
-      "@_documentation attribute's 'visibility' argument expected an access level",
+      "'_documentation' attribute's 'visibility' argument expected an access level",
       ())
 ERROR(documentation_attr_unknown_access_level,none,
       "unknown visibility '%0', expected an access level keyword",
@@ -1852,26 +1866,26 @@ ERROR(documentation_attr_unknown_access_level,none,
 ERROR(documentation_attr_duplicate_visibility,none,
       "cannot give more than one visibility to the same item", ())
 ERROR(documentation_attr_metadata_expected_text,none,
-      "@_documentation attribute's 'metadata' argument expected an identifier or "
+      "'_documentation' attribute's 'metadata' argument expected an identifier or "
       "quoted string",
       ())
 ERROR(documentation_attr_duplicate_metadata,none,
       "cannot give more than one metadata argument to the same item", ())
 
 ERROR(attr_rawlayout_expected_label,none,
-      "expected %0 argument to @_rawLayout attribute", (StringRef))
+      "expected %0 argument to '@_rawLayout'", (StringRef))
 ERROR(attr_rawlayout_expected_integer_size,none,
-      "expected integer literal size in @_rawLayout attribute", ())
+      "expected integer literal size in '@_rawLayout'", ())
 ERROR(attr_rawlayout_expected_integer_alignment,none,
-      "expected integer literal alignment in @_rawLayout attribute", ())
+      "expected integer literal alignment in '@_rawLayout'", ())
 ERROR(attr_rawlayout_expected_params,none,
-      "expected %1 argument after %0 argument in @_rawLayout attribute", (StringRef, StringRef))
+      "expected %1 argument after %0 argument in '@_rawLayout'", (StringRef, StringRef))
 
 ERROR(attr_extern_expected_label,none,
-      "expected %0 argument to @_extern attribute", (StringRef))
+      "expected %0 argument to '@_extern'", (StringRef))
 
 ERROR(attr_expected_feature_name,none,
-      "expected feature name in @%0 attribute", (StringRef))
+      "expected feature name in '@%0'", (StringRef))
 
 //------------------------------------------------------------------------------
 // MARK: Generics parsing diagnostics
@@ -2064,13 +2078,13 @@ ERROR(macro_role_syntax_mismatch,PointsToFirstBadToken,
       "%select{a freestanding|an attached}0 macro cannot have the %1 role",
       (bool, Identifier))
 ERROR(macro_attribute_unknown_label,PointsToFirstBadToken,
-      "@%select{freestanding|attached}0 has no argument with label %1",
+      "'@%select{freestanding|attached}0' has no argument with label %1",
       (bool, Identifier))
 ERROR(macro_attribute_duplicate_label,PointsToFirstBadToken,
-      "@%select{freestanding|attached}0 already has an argument with "
+      "'@%select{freestanding|attached}0' already has an argument with "
       "label %1", (bool, StringRef))
 ERROR(macro_attribute_missing_label,none,
-      "@%select{freestanding|attached}0 argument is missing label '%1'",
+      "'@%select{freestanding|attached}0' argument is missing label '%1'",
       (bool, StringRef))
 ERROR(macro_attribute_unknown_name_kind,PointsToFirstBadToken,
       "unknown introduced name kind %0", (Identifier))
@@ -2081,7 +2095,8 @@ ERROR(macro_attribute_introduced_name_requires_argument,PointsToFirstBadToken,
 ERROR(macro_attribute_introduced_name_requires_no_argument,PointsToFirstBadToken,
       "introduced name kind %0 must not have an argument", (Identifier))
 WARNING(macro_expression_attribute_removed,PointsToFirstBadToken,
-      "@expression has been removed in favor of @freestanding(expression)", ())
+      "'@expression' has been removed in favor of '@freestanding(expression)'",
+      ())
 
 ERROR(unexpected_attribute_expansion,PointsToFirstBadToken,
       "unexpected token '%0' in expanded attribute list",
@@ -2117,16 +2132,16 @@ ERROR(init_accessor_is_not_in_the_primary_declaration,none,
       ())
 
 ERROR(missing_storage_restrictions_attr_label,none,
-      "missing label in @storageRestrictions attribute", ())
+      "missing label in '@storageRestrictions'", ())
 
 ERROR(invalid_storage_restrictions_attr_label,none,
-      "unexpected label %0 in @storageRestrictions attribute", (Identifier))
+      "unexpected label %0 in '@storageRestrictions'", (Identifier))
 
 ERROR(duplicate_storage_restrictions_attr_label,none,
-      "duplicate label %0 in @storageRestrictions attribute", (Identifier))
+      "duplicate label %0 in '@storageRestrictions'", (Identifier))
 
 ERROR(storage_restrictions_attr_expected_name,none,
-      "expected property name in @storageRestrictions list", ())
+      "expected property name in '@storageRestrictions' list", ())
 
 ERROR(requires_experimental_feature, none,
       "'%0' %select{attribute|parameter specifier}1 is only valid when experimental feature "
@@ -2142,7 +2157,7 @@ ERROR(expected_lparen_after_lifetime_dependence, PointsToFirstBadToken,
 
 ERROR(expected_identifier_or_index_or_self_after_lifetime_dependence,
       PointsToFirstBadToken,
-      "expected identifier, index or self in lifetime dependence specifier",
+      "expected 'copy', 'borrow', or '&' followed by an identifier, index or 'self' in lifetime dependence specifier",
       ())
 
 ERROR(expected_rparen_after_lifetime_dependence, PointsToFirstBadToken,
@@ -2169,5 +2184,27 @@ ERROR(sil_thunkinst_failed_to_parse_kind,none,
 ERROR(sil_failed_to_parse_sil_optional,none,
       "Expected SIL optional value of the form '[' NAME ']'", ())
 
+//------------------------------------------------------------------------------
+// MARK: nonisolated(nonsending)
+//------------------------------------------------------------------------------
+
+ERROR(nonisolated_nonsending_expected_lparen,PointsToFirstBadToken,
+      "expected '(' following 'nonisolated'", ())
+ERROR(nonisolated_nonsending_incorrect_modifier,PointsToFirstBadToken,
+      "expected 'nonsending' in modifier", ())
+ERROR(nonisolated_nonsending_expected_rparen,PointsToFirstBadToken,
+      "expected ')' after 'nonisolated' modifier", ())
+ERROR(nonisolated_nonsending_repeated,none,
+      "parameter may have at most one 'nonisolated(nonsending)' specifier", ())
+
+//------------------------------------------------------------------------------
+// MARK: using @<attribute> or using <identifier>
+//------------------------------------------------------------------------------
+ERROR(using_decl_invalid_specifier,PointsToFirstBadToken,
+      "default isolation can only be set to '@MainActor' or 'nonisolated'",
+      ())
+ERROR(experimental_using_decl_disabled,PointsToFirstBadToken,
+      "'using' is an experimental feature that is currently disabled", ())
+
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"
diff --git a/include/swift/AST/DiagnosticsSIL.def b/include/swift/AST/DiagnosticsSIL.def
index 8237db1f11b8c..0b744c0debd19 100644
--- a/include/swift/AST/DiagnosticsSIL.def
+++ b/include/swift/AST/DiagnosticsSIL.def
@@ -84,7 +84,7 @@ ERROR(unimplemented_generator_witnesses,none,
       "protocol conformance emission for generator coroutines is unimplemented",
       ())
 
-ERROR(exclusivity_access_required,none,
+GROUPED_ERROR(exclusivity_access_required,ExclusivityViolation,none,
       "overlapping accesses to %0, but "
       "%select{initialization|read|modification|deinitialization}1 requires "
       "exclusive access; "
@@ -92,18 +92,18 @@ ERROR(exclusivity_access_required,none,
               "consider calling MutableCollection.swapAt(_:_:)}2",
       (StringRef, unsigned, bool))
 
-ERROR(exclusivity_access_required_unknown_decl,none,
+GROUPED_ERROR(exclusivity_access_required_unknown_decl,ExclusivityViolation,none,
         "overlapping accesses, but "
         "%select{initialization|read|modification|deinitialization}0 requires "
         "exclusive access; consider copying to a local variable", (unsigned))
 
-ERROR(exclusivity_access_required_moveonly,none,
+GROUPED_ERROR(exclusivity_access_required_moveonly,ExclusivityViolation,none,
       "overlapping accesses to %0, but "
       "%select{initialization|read|modification|deinitialization}1 requires "
       "exclusive access",
       (StringRef, unsigned))
 
-ERROR(exclusivity_access_required_unknown_decl_moveonly,none,
+GROUPED_ERROR(exclusivity_access_required_unknown_decl_moveonly,ExclusivityViolation,none,
         "overlapping accesses, but "
         "%select{initialization|read|modification|deinitialization}0 requires "
         "exclusive access", (unsigned))
@@ -143,7 +143,7 @@ ERROR(deserialize_function_type_mismatch,Fatal,
       (StringRef, Type, Type))
 
 ERROR(without_actually_escaping_on_isolated_any,none,
-      "withoutActuallyEscaping is currently unimplemented for @isolated(any) "
+      "withoutActuallyEscaping is currently unimplemented for '@isolated(any)' "
       "function values", ())
 
 // Capture before declaration diagnostics.
@@ -315,12 +315,12 @@ ERROR(missing_never_call_closure,none,
       (Type))
 
 ERROR(missing_return_decl,none,
-      "missing return in %1 expected to return %0",
-      (Type, DescriptiveDeclKind))
+      "missing return in %kindonly1 expected to return %0",
+      (Type, const AbstractFunctionDecl *))
 ERROR(missing_never_call_decl,none,
-      "%1 with uninhabited return type %0 is missing "
+      "%kindonly1 with uninhabited return type %0 is missing "
       "call to another never-returning function on all paths",
-      (Type, DescriptiveDeclKind))
+      (Type, const AbstractFunctionDecl *))
 
 NOTE(missing_return_last_expr_note,none,
     "did you mean to return the last expression?", ())
@@ -378,40 +378,69 @@ ERROR(bad_attr_on_non_const_global,none,
       "global variable must be a compile-time constant to use %0 attribute", (StringRef))
 ERROR(global_must_be_compile_time_const,none,
       "global variable must be a compile-time constant", ())
-ERROR(non_final_generic_class_function,none,
-      "classes cannot have non-final generic functions in embedded Swift", ())
-ERROR(cannot_specialize_witness_method,none,
-      "an existential type cannot contain a generic method %0 in embedded Swift", (DeclName))
-ERROR(cannot_specialize_class,none,
+ERROR(perf_diag_existential_type,none,
+      "cannot use a value of protocol type %0 in '@_noExistential' function", (Type))
+ERROR(perf_diag_existential,none,
+      "cannot use a value of protocol type in '@_noExistential' function", ())
+
+// Embedded Swift diagnostics
+GROUPED_ERROR(embedded_cannot_specialize_class_method,EmbeddedRestrictions,none,
+      "classes cannot have a non-final, generic method %0 in embedded Swift", (DeclName))
+GROUPED_ERROR(embedded_cannot_specialize_witness_method,EmbeddedRestrictions,none,
+      "a protocol type cannot contain a generic method %0 in embedded Swift", (DeclName))
+GROUPED_ERROR(cannot_specialize_class,EmbeddedRestrictions,none,
       "cannot specialize %0 because class definition is not available (make sure to build with -wmo)", (Type))
-ERROR(embedded_swift_existential_type,none,
+GROUPED_ERROR(embedded_swift_existential_type,EmbeddedRestrictions,none,
       "cannot use a value of protocol type %0 in embedded Swift", (Type))
-ERROR(embedded_swift_existential,none,
+GROUPED_ERROR(embedded_swift_existential_protocol,EmbeddedRestrictions,none,
+      "cannot use a value of protocol type 'any %0' in embedded Swift", (StringRef))
+GROUPED_ERROR(embedded_swift_existential,EmbeddedRestrictions,none,
       "cannot use a value of protocol type in embedded Swift", ())
-ERROR(perf_diag_existential_type,none,
-      "cannot use a value of protocol type %0 in @_noExistential function", (Type))
-ERROR(perf_diag_existential,none,
-      "cannot use a value of protocol type in @_noExistential function", ())
-ERROR(embedded_swift_value_deinit,none,
+GROUPED_ERROR(embedded_swift_value_deinit,EmbeddedRestrictions,none,
       "cannot de-virtualize deinit of type %0", (Type))
-ERROR(embedded_swift_metatype_type,none,
+GROUPED_ERROR(embedded_swift_metatype_type,EmbeddedRestrictions,none,
       "cannot use metatype of type %0 in embedded Swift", (Type))
-ERROR(embedded_swift_metatype,none,
+GROUPED_ERROR(embedded_swift_metatype,EmbeddedRestrictions,none,
       "cannot use metatype in embedded Swift", ())
-ERROR(embedded_swift_keypath,none,
+GROUPED_ERROR(embedded_swift_keypath,EmbeddedRestrictions,none,
       "cannot use key path in embedded Swift", ())
-ERROR(embedded_swift_dynamic_cast,none,
+GROUPED_ERROR(embedded_swift_dynamic_cast,EmbeddedRestrictions,none,
       "cannot do dynamic casting in embedded Swift", ())
+GROUPED_ERROR(embedded_capture_of_generic_value_with_deinit,EmbeddedRestrictions,none,
+      "capturing generic non-copyable type with deinit in escaping closure not supported in embedded Swift", ())
+GROUPED_ERROR(embedded_call_generic_function,EmbeddedRestrictions,none,
+      "cannot specialize generic function or default protocol method in this context", ())
+GROUPED_ERROR(embedded_call_generic_function_with_dynamic_self,EmbeddedRestrictions,none,
+      "cannot call an initializer or static method, which is defined as default protocol method, from a class method or initializer", ())
+NOTE(embedded_specialization_called_from,none,
+      "generic specialization called here", ())
+NOTE(embedded_existential_created,none,
+      "protocol type value created here", ())
+NOTE(embedded_constructor_called,none,
+      "instance of type created here", ())
+
+// no-allocations diagnostics
 ERROR(embedded_swift_allocating_type,none,
       "cannot use allocating type %0 in -no-allocations mode", (Type))
+ERROR(embedded_swift_allocating_coroutine,none,
+      "cannot use co-routines (like accessors) in -no-allocations mode", ())
+ERROR(embedded_swift_allocating_closure,none,
+      "cannot use escaping closures in -no-allocations mode", ())
 ERROR(embedded_swift_allocating,none,
       "cannot use allocating operation in -no-allocations mode", ())
-ERROR(embedded_capture_of_generic_value_with_deinit,none,
-      "capturing generic non-copyable type with deinit in escaping closure not supported in embedded Swift", ())
+
 ERROR(wrong_linkage_for_serialized_function,none,
       "function has wrong linkage to be called from %0", (StringRef))
 NOTE(performance_called_from,none,
       "called from here", ())
+ERROR(manualownership_copy,none,
+      "explicit 'copy' required here; please report this vague diagnostic as a bug", ())
+ERROR(manualownership_copy_happened,none,
+      "accessing %0 may produce a copy; write 'copy' to acknowledge or 'consume' to elide", (Identifier))
+ERROR(manualownership_copy_demanded,none,
+      "independent copy of %0 is required here; write 'copy' to acknowledge or 'consume' to elide", (Identifier))
+ERROR(manualownership_copy_captured,none,
+      "closure capture of '%0' requires independent copy of it; write [%0 = copy %0] in the closure's capture list to acknowledge", (StringRef))
 
 // 'transparent' diagnostics
 ERROR(circular_transparent,none,
@@ -419,6 +448,10 @@ ERROR(circular_transparent,none,
 NOTE(note_while_inlining,none,
      "while inlining here", ())
 
+// '@inline(always)' diagnostics
+ERROR(circular_inlineAlways,none,
+      "inlining '@inline(always)' functions forms circular loop", ())
+
 // Pre-specializations
 ERROR(cannot_prespecialize,none,
       "Cannot pre-specialize %0", (StringRef))
@@ -701,8 +734,9 @@ WARNING(warning_int_to_fp_inexact, none,
 
 // Flow-isolation diagnostics
 ERROR(isolated_after_nonisolated, none,
-      "cannot access %1 %2 here in %select{nonisolated initializer|deinitializer}0",
-      (bool, DescriptiveDeclKind, DeclName))
+      "cannot access %kind1 here in "
+      "%select{nonisolated initializer|deinitializer}0",
+      (bool, const ValueDecl *))
 NOTE(nonisolated_blame, none, "after %1%2 %3, "
      "only nonisolated properties of 'self' can be accessed from "
      "%select{this init|a deinit}0", (bool, StringRef, StringRef, DeclName))
@@ -809,7 +843,7 @@ NOTE(capturepromotion_variable_defined_here,none,
 
 // noimplicitcopy on generic or existential binding
 ERROR(noimplicitcopy_used_on_generic_or_existential, none,
-      "@_noImplicitCopy can not be used on a generic or existential typed "
+      "'@_noImplicitCopy' can not be used on a generic or existential typed "
       "binding or a nominal type containing such typed things", ())
 
 // discard statement
@@ -840,7 +874,8 @@ ERROR(sil_movechecking_borrowed_parameter_captured_by_closure, none,
       "parameter",
       (StringRef))
 ERROR(sil_movechecking_capture_consumed, none,
-      "noncopyable '%0' cannot be consumed when captured by an escaping closure", (StringRef))
+      "noncopyable '%0' cannot be consumed when captured by an escaping closure or borrowed by a non-Escapable type",
+      (StringRef))
 ERROR(sil_movechecking_not_reinitialized_before_end_of_function, none,
       "missing reinitialization of %select{inout parameter|closure capture}1 '%0' "
       "after consume", (StringRef, bool))
@@ -864,7 +899,8 @@ ERROR(sil_movechecking_cannot_destructure_imported_nonfrozen, none,
       "cannot partially consume '%0' of non-frozen type %1 imported from %2",
       (StringRef, Type, const ModuleDecl*))
 ERROR(sil_movechecking_cannot_destructure_exported_usableFromInline_alwaysEmitIntoClient, none,
-      "cannot partially consume '%0' of non-frozen usableFromInline type %1 within a function annotated @_alwaysEmitIntoClient",
+      "cannot partially consume '%0' of non-frozen usableFromInline type %1 "
+      "within a function annotated '@_alwaysEmitIntoClient'",
       (StringRef, Type))
 ERROR(sil_movechecking_cannot_destructure, none,
       "cannot partially consume '%0'",
@@ -876,7 +912,8 @@ ERROR(sil_movechecking_cannot_partially_reinit_nonfrozen, none,
       "cannot partially reinitialize '%0' of non-frozen type %1 imported from %2; only full reinitialization is allowed",
       (StringRef, Type, const ModuleDecl*))
 ERROR(sil_movechecking_cannot_partially_reinit_exported_usableFromInline_alwaysEmitIntoClient, none,
-      "cannot partially reinitialize '%0' of non-frozen usableFromInline type %1 within a function annotated @_alwaysEmitIntoClient",
+      "cannot partially reinitialize '%0' of non-frozen usableFromInline type "
+      "%1 within a function annotated '@_alwaysEmitIntoClient'",
       (StringRef, Type))
 ERROR(sil_movechecking_cannot_partially_reinit, none,
       "cannot partially reinitialize '%0' after it has been consumed; only full reinitialization is allowed",
@@ -947,10 +984,10 @@ NOTE(sil_referencebinding_inout_binding_here, none,
       ())
 
 //===----------------------------------------------------------------------===//
-//                  MARK: Region Based Isolation Diagnostics
+//                  MARK: Region-Based Isolation Diagnostics
 //===----------------------------------------------------------------------===//
 
-// READ THIS: Please when adding diagnostics for region based isolation, keep
+// READ THIS: Please when adding diagnostics for region-based isolation, keep
 // them ordered in sections depending on which emitter uses it. It makes it
 // easier for people unfamiliar with the code to quickly see which diagnostics
 // are used by which of the SendNonSendable emitters use.
@@ -959,7 +996,7 @@ NOTE(sil_referencebinding_inout_binding_here, none,
 // Misc
 
 ERROR(regionbasedisolation_unknown_pattern, none,
-      "pattern that the region based isolation checker does not understand how to check. Please file a bug",
+      "pattern that the region-based isolation checker does not understand how to check. Please file a bug",
       ())
 NOTE(regionbasedisolation_maybe_race, none,
      "access can happen concurrently", ())
@@ -979,23 +1016,23 @@ GROUPED_ERROR(regionbasedisolation_type_send_yields_race, SendingRisksDataRace,
       (Type))
 NOTE(regionbasedisolation_type_use_after_send, none,
       "sending value of non-Sendable type %0 to %1 callee risks causing data races between %1 and local %2 uses",
-      (Type, ActorIsolation, ActorIsolation))
+      (Type, StringRef, StringRef))
 NOTE(regionbasedisolation_type_use_after_send_callee, none,
-     "sending value of non-Sendable type %0 to %1 %2 %3 risks causing data "
-     "races between %1 and local %4 uses",
-     (Type, ActorIsolation, DescriptiveDeclKind, DeclName, ActorIsolation))
+     "sending value of non-Sendable type %0 to %1 %kind2 risks causing data "
+     "races between %1 and local %3 uses",
+     (Type, StringRef, const ValueDecl *, StringRef))
 
 NOTE(regionbasedisolation_named_info_send_yields_race, none,
-     "sending %1%0 to %2 callee risks causing data races between %2 and local %3 uses",
-     (Identifier, StringRef, ActorIsolation, ActorIsolation))
+     "sending %select{%2 |}0%1 to %3 callee risks causing data races between %3 and local %4 uses",
+     (bool, Identifier, StringRef, StringRef, StringRef))
 NOTE(regionbasedisolation_named_info_send_yields_race_callee, none,
-     "sending %1%0 to %2 %3 %4 risks causing data races between %2 and local %5 uses",
-     (Identifier, StringRef, ActorIsolation, DescriptiveDeclKind, DeclName, ActorIsolation))
+     "sending %select{%2 |}0%1 to %3 %kind4 risks causing data races between %3 and local %5 uses",
+     (bool, Identifier, StringRef, StringRef, const ValueDecl *, StringRef))
 
 // Use after send closure.
 NOTE(regionbasedisolation_type_isolated_capture_yields_race, none,
       "sending value of non-Sendable type %0 to %1 closure due to closure capture risks causing races in between %1 and %2 uses",
-      (Type, ActorIsolation, ActorIsolation))
+      (Type, StringRef, StringRef))
 
 // Value captured in async let and reused.
 NOTE(regionbasedisolation_named_nonisolated_asynclet_name, none,
@@ -1006,33 +1043,33 @@ NOTE(regionbasedisolation_named_value_used_after_explicit_sending, none,
       "%0 used after being passed as a 'sending' parameter; Later uses could race",
       (Identifier))
 NOTE(regionbasedisolation_named_isolated_closure_yields_race, none,
-      "%0%1 is captured by a %2 closure. %2 uses in closure may race against later %3 uses",
-      (StringRef, Identifier, ActorIsolation, ActorIsolation))
+      "%select{%1 |}0%2 is captured by a %3 closure. %3 uses in closure may race against later %4 uses",
+      (bool, StringRef, Identifier, StringRef, StringRef))
 
 NOTE(regionbasedisolation_typed_use_after_sending, none,
       "Passing value of non-Sendable type %0 as a 'sending' argument risks causing races in between local and caller code",
       (Type))
 NOTE(regionbasedisolation_typed_use_after_sending_callee, none,
-      "Passing value of non-Sendable type %0 as a 'sending' argument to %1 %2 risks causing races in between local and caller code",
-      (Type, DescriptiveDeclKind, DeclName))
+      "Passing value of non-Sendable type %0 as a 'sending' argument to %kind1 risks causing races in between local and caller code",
+      (Type, const ValueDecl *))
 
 //===
 // Sending Never Sendable Emitter
 
 NOTE(regionbasedisolation_named_send_never_sendable, none,
-      "sending %1%0 to %2 callee risks causing data races between %2 and %3 uses",
-      (Identifier, StringRef, ActorIsolation, StringRef))
+      "sending %select{%2 |}0%1 to %3 callee risks causing data races between %3 and %4 uses",
+      (bool, Identifier, StringRef, StringRef, StringRef))
 NOTE(regionbasedisolation_named_send_never_sendable_callee, none,
-      "sending %1%0 to %2 %3 %4 risks causing data races between %2 and %5 uses",
-      (Identifier, StringRef, ActorIsolation, DescriptiveDeclKind, DeclName, StringRef))
+      "sending %select{%2 |}0%1 to %3 %kind4 risks causing data races between %3 and %5 uses",
+      (bool, Identifier, StringRef, StringRef, const ValueDecl *, StringRef))
 
 NOTE(regionbasedisolation_named_send_into_sending_param, none,
-     "%0%1 is passed as a 'sending' parameter; Uses in callee may race with "
-     "later %0uses",
-     (StringRef, Identifier))
+     "%select{%1 |}0%2 is passed as a 'sending' parameter; Uses in callee may race with "
+     "later %1 uses",
+     (bool, StringRef, Identifier))
 NOTE(regionbasedisolation_named_nosend_send_into_result, none,
-     "%0%1 cannot be a 'sending' result. %2 uses may race with caller uses",
-     (StringRef, Identifier, StringRef))
+     "%select{%1 |}0%2 cannot be a 'sending' result. %3 uses may race with caller uses",
+     (bool, StringRef, Identifier, StringRef))
 NOTE(regionbasedisolation_typed_tns_passed_to_sending, none,
      "Passing %0 value of non-Sendable type %1 as a 'sending' parameter risks "
      "causing races inbetween %0 uses and uses reachable from the callee",
@@ -1048,8 +1085,8 @@ NOTE(regionbasedisolation_typed_tns_passed_to_sending_closure_helper_have_value_
      "closure captures %0 which is accessible to code in the current task",
      (DeclName))
 NOTE(regionbasedisolation_typed_tns_passed_to_sending_closure_helper_have_boxed_value_task_isolated, none,
-     "closure captures reference to mutable %1 %0 which is accessible to code in the current task",
-     (DeclName, DescriptiveDeclKind))
+     "closure captures reference to mutable %kind0 which is accessible to code in the current task",
+     (const ValueDecl *))
 NOTE(regionbasedisolation_typed_tns_passed_to_sending_closure_helper_have_value_region, none,
      "closure captures %1 which is accessible to %0 code",
      (StringRef, DeclName))
@@ -1065,36 +1102,66 @@ NOTE(regionbasedisolation_closure_captures_actor, none,
      (DeclName, StringRef))
 
 NOTE(regionbasedisolation_typed_tns_passed_to_sending_callee, none,
-     "Passing %0 value of non-Sendable type %1 as a 'sending' parameter to %2 %3 risks causing races inbetween %0 uses and uses reachable from %3",
-     (StringRef, Type, DescriptiveDeclKind, DeclName))
+     "Passing %0 value of non-Sendable type %1 as a 'sending' parameter to %kind2 risks causing races inbetween %0 uses and uses reachable from %2",
+     (StringRef, Type, const ValueDecl *))
 
 NOTE(regionbasedisolation_named_send_nt_asynclet_capture, none,
       "sending %1 %0 into async let risks causing data races between nonisolated and %1 uses",
       (Identifier, StringRef))
 NOTE(regionbasedisolation_typed_sendneversendable_via_arg, none,
       "sending %0 value of non-Sendable type %1 to %2 callee risks causing races in between %0 and %2 uses",
-      (StringRef, Type, ActorIsolation))
+      (StringRef, Type, StringRef))
 NOTE(regionbasedisolation_typed_sendneversendable_via_arg_callee, none,
-      "sending %0 value of non-Sendable type %1 to %2 %3 %4 risks causing races in between %0 and %2 uses",
-      (StringRef, Type, ActorIsolation, DescriptiveDeclKind, DeclName))
+      "sending %0 value of non-Sendable type %1 to %2 %kind3 risks causing races in between %0 and %2 uses",
+      (StringRef, Type, StringRef, const ValueDecl *))
+
+NOTE(regionbasedisolation_isolated_conformance_introduced, none,
+     "isolated conformance to %kind0 can be introduced here",
+     (const ValueDecl *))
 
 // Error that is only used when the send non sendable emitter cannot discover any
 // information to give a better diagnostic.
 ERROR(regionbasedisolation_task_or_actor_isolated_sent, none,
-      "task or actor isolated value cannot be sent", ())
+      "task or actor-isolated value cannot be sent", ())
 
 //===
 // InOut Sending Emitter
 
 NOTE(regionbasedisolation_inout_sending_must_be_reinitialized, none,
-     "'inout sending' parameter must be reinitialized before function exit with a non-actor isolated value",
+     "'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value",
      ())
 ERROR(regionbasedisolation_inout_sending_cannot_be_actor_isolated, none,
-      "'inout sending' parameter %0 cannot be %1at end of function",
+      "'inout sending' parameter %0 cannot be %1 at end of function",
       (Identifier, StringRef))
 NOTE(regionbasedisolation_inout_sending_cannot_be_actor_isolated_note, none,
-      "%1%0 risks causing races in between %1uses and caller uses since caller assumes value is not actor isolated",
+      "%1 %0 risks causing races in between %1 uses and caller uses since caller assumes value is not actor isolated",
       (Identifier, StringRef))
+ERROR(regionbasedisolation_inout_sending_cannot_be_returned_param, none,
+      "'inout sending' parameter %0 cannot be returned",
+      (Identifier))
+ERROR(regionbasedisolation_inout_sending_cannot_be_returned_value, none,
+      "%0 cannot be returned",
+      (Identifier))
+ERROR(regionbasedisolation_inout_sending_cannot_be_returned_value_result, none,
+      "result of %kind0 cannot be returned",
+      (const ValueDecl *))
+NOTE(regionbasedisolation_inout_sending_cannot_be_returned_note_param, none,
+     "returning 'inout sending' parameter %0 risks concurrent access as caller assumes %0 and result can be sent to different isolation domains",
+     (Identifier))
+NOTE(regionbasedisolation_inout_sending_cannot_be_returned_note_value, none,
+     "returning %0 risks concurrent access to 'inout sending' parameter %1 as caller assumes %1 and result can be sent to different isolation domains",
+     (Identifier, Identifier))
+NOTE(regionbasedisolation_inout_sending_cannot_be_returned_note_return_value, none,
+     "returning result of %kind0 risks concurrent access to 'inout sending' parameter %1 as caller assumes %1 and result can be sent to different isolation domains",
+     (const ValueDecl *, Identifier))
+NOTE(regionbasedisolation_inout_sending_cannot_be_returned_note_actor_param, none,
+     "returning %0 risks concurrent access as caller assumes %0 is not actor-isolated and result is %1", (Identifier, StringRef))
+NOTE(regionbasedisolation_inout_sending_cannot_be_returned_note_actor_value, none,
+     "returning %0 risks concurrent access to 'inout sending' parameter %1 as caller assumes %1 is not actor-isolated and result is %2",
+     (Identifier, Identifier, StringRef))
+NOTE(regionbasedisolation_inout_sending_cannot_be_returned_note_actor_return_value, none,
+     "returning result of %kind0 risks concurrent access to 'inout sending' parameter %1 as caller assumes %1 is not actor-isolated and result is %2",
+     (const ValueDecl *, Identifier, StringRef))
 
 //===
 // Out Sending
@@ -1118,10 +1185,10 @@ NOTE(regionbasedisolation_out_sending_cannot_be_actor_isolated_note_named, none,
 // Example: returning main-actor isolated result to a custom-actor isolated context risks causing data races
 ERROR(rbi_isolation_crossing_result, none,
       "non-Sendable %0-typed result can not be returned from %1 %kind2 to %3 context",
-      (Type, ActorIsolation, const ValueDecl *, ActorIsolation))
+      (Type, StringRef, const ValueDecl *, StringRef))
 ERROR(rbi_isolation_crossing_result_no_decl, none,
       "non-Sendable %0-typed result can not be returned from %1 function to %2 context",
-      (Type, ActorIsolation, ActorIsolation))
+      (Type, StringRef, StringRef))
 NOTE(rbi_non_sendable_nominal,none,
      "%kind0 does not conform to the 'Sendable' protocol",
       (const ValueDecl *))
@@ -1136,12 +1203,9 @@ NOTE(rbi_add_generic_parameter_sendable_conformance,none,
 
 // Concurrency related diagnostics
 ERROR(cannot_find_executor_factory_type, none,
-      "the specified executor factory '%0' could not be found", (StringRef))
+      "the DefaultExecutorFactory type could not be found", ())
 ERROR(executor_factory_must_conform, none,
-      "the executor factory '%0' does not conform to 'ExecutorFactory'",
-      (StringRef))
-ERROR(executor_factory_not_supported, none,
-      "deployment target too low for executor factory specification", ())
+      "the DefaultExecutorFactory does not conform to 'ExecutorFactory'", ())
 
 //===----------------------------------------------------------------------===//
 //                           MARK: Misc Diagnostics
@@ -1155,21 +1219,43 @@ ERROR(lifetime_variable_outside_scope, none,
       "lifetime-dependent variable '%0' escapes its scope", (Identifier))
 ERROR(lifetime_value_outside_scope, none,
       "lifetime-dependent value escapes its scope", ())
+ERROR(lifetime_value_outside_accessor, none,
+      "lifetime-dependent value returned by generated accessor '%0'", (StringRef))
+ERROR(lifetime_value_outside_thunk, none,
+      "lifetime-dependent value returned by generated %select{function|thunk}0 '%1'", (bool, StringRef))
 NOTE(lifetime_outside_scope_argument, none,
      "it depends on the lifetime of argument '%0'", (Identifier))
+NOTE(lifetime_outside_scope_synthesized_argument, none,
+     "it depends on the lifetime of an argument of '%0'", (Identifier))
 NOTE(lifetime_outside_scope_access, none,
      "it depends on this scoped access to variable '%0'", (Identifier))
 NOTE(lifetime_outside_scope_variable, none,
      "it depends on the lifetime of variable '%0'", (Identifier))
 NOTE(lifetime_outside_scope_value, none,
      "it depends on the lifetime of this parent value", ())
+NOTE(lifetime_outside_scope_capture, none,
+     "it depends on a closure capture; this is not yet supported", ())
 NOTE(lifetime_outside_scope_use, none,
      "this use of the lifetime-dependent value is out of scope", ())
 NOTE(lifetime_outside_scope_escape, none,
      "this use causes the lifetime-dependent value to escape", ())
 
+NOTE(implicit_function_note, none, "error in compiler-generated '%0'", (StringRef))
+
 ERROR(noncopyable_shared_case_block_unimplemented, none,
       "matching a non-'Copyable' value using a case label that has multiple patterns is not implemented", ())
 
+
+/// Borrow and mutate accessors
+ERROR(invalid_borrow_accessor_return, none,
+      "invalid return value from borrow accessor", ())
+NOTE(borrow_accessor_not_a_projection_note, none,
+     "borrow accessors can return either literals, stored properties or computed "
+     "properties that have borrow accessors",
+     ())
+ERROR(invalid_multiple_return_borrow_accessor, none,
+      "multiple return statements in borrow accessors are not yet supported",
+      ())
+
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"
diff --git a/include/swift/AST/DiagnosticsSema.def b/include/swift/AST/DiagnosticsSema.def
index 2e9f8b78c95f8..dbee278386036 100644
--- a/include/swift/AST/DiagnosticsSema.def
+++ b/include/swift/AST/DiagnosticsSema.def
@@ -42,6 +42,8 @@ NOTE(opaque_return_type_declared_here,none,
      "opaque return type declared here", ())
 NOTE(default_value_declared_here,none,
      "default value declared here", ())
+NOTE(requirement_declared_here,none,
+     "requirement %0 declared here", (const ValueDecl *))
 
 //------------------------------------------------------------------------------
 // MARK: Constraint solver diagnostics
@@ -165,11 +167,20 @@ ERROR(init_candidate_inaccessible,none,
       "'%select{private|fileprivate|internal|package|@_spi|@_spi}1' protection level",
       (Type, AccessLevel))
 
-ERROR(candidate_from_missing_import,none,
-      "%0 %1 is not available due to missing import of defining module %2",
-      (DescriptiveDeclKind, DeclName, ModuleDecl *))
+GROUPED_ERROR(member_from_missing_import,MemberImportVisibility,none,
+      "%kind0 is not available due to missing import of defining module %1",
+      (const ValueDecl *, const ModuleDecl *))
+GROUPED_ERROR(member_from_missing_imports_2_or_more,MemberImportVisibility,none,
+      "%kind0 is not available due to missing imports of defining modules "
+      "%2%select{ and|, }1 %3%select{|, and others}1",
+      (const ValueDecl *, bool, const ModuleDecl *, const ModuleDecl *))
 NOTE(candidate_add_import,none,
-     "add import of module %0", (ModuleDecl *))
+     "add import of module %0", (const ModuleDecl *))
+
+GROUPED_WARNING(add_required_import_for_member,MemberImportVisibility,none,
+     "import of module %0 is required", (const ModuleDecl *))
+NOTE(decl_from_module_used_here,none,
+     "%kind0 from %1 used here", (const ValueDecl *, const ModuleDecl *))
 
 ERROR(cannot_pass_rvalue_mutating_subelement,none,
       "cannot use mutating member on immutable value: %0",
@@ -243,13 +254,6 @@ ERROR(cannot_apply_lvalue_binop_to_subelement,none,
 ERROR(cannot_apply_lvalue_binop_to_rvalue,none,
       "left side of mutating operator has immutable type %0", (Type))
 
-ERROR(cannot_subscript_base,none,
-      "cannot subscript a value of type %0",
-      (Type))
-
-ERROR(cannot_subscript_ambiguous_base,none,
-      "cannot subscript a value of incorrect or ambiguous type", ())
-
 ERROR(cannot_subscript_nil_literal,none,
       "cannot subscript a nil literal value", ())
 ERROR(conditional_cast_from_nil,none,
@@ -310,13 +314,13 @@ ERROR(incorrect_explicit_closure_result_vs_return_type,none,
       (Type, Type))
 
 ERROR(addressable_not_enabled,none,
-      "@_addressable is an experimental feature", ())
+      "'@_addressable' is an experimental feature", ())
 ERROR(addressableSelf_not_on_method,none,
-      "@_addressableSelf cannot be applied to non-member declarations", ())
+      "'@_addressableSelf' cannot be applied to non-member declarations", ())
 ERROR(addressable_types_not_enabled,none,
-      "@_addressableForDependencies is an experimental feature", ())
+      "'@_addressableForDependencies' is an experimental feature", ())
 ERROR(class_cannot_be_addressable_for_dependencies,none,
-      "a class cannot be @_addressableForDependencies", ())
+      "a class cannot be '@_addressableForDependencies'", ())
 
 ERROR(unsupported_closure_attr,none,
       "%select{attribute |}0%1 is not supported on a closure",
@@ -355,6 +359,11 @@ ERROR(cannot_convert_return_type_to_anyobject,none,
 ERROR(cannot_convert_to_return_type_nil,none,
       "'nil' is incompatible with return type %0", (Type))
 
+ERROR(cannot_convert_metatype_to_non_metatype,none,
+      "cannot convert metatype %0 to non-metatype %1", (Type, Type))
+ERROR(cannot_convert_typeof_to_non_metatype,none,
+      "cannot convert 'type(of:)' metatype to non-metatype %0", (Type))
+
 ERROR(cannot_convert_thrown_type,none,
       "thrown expression type %0 %select{cannot be converted to error type %1|"
       "does not conform to 'Error'}2",
@@ -594,8 +603,8 @@ ERROR(cannot_convert_assign,none,
       "cannot assign value of type %0 to type %1",
       (Type,Type))
 NOTE(assign_protocol_conformance_fix_it,none,
-     "add missing conformance to %0 to %1 %2",
-     (Type, DescriptiveDeclKind, Type))
+     "add missing conformance to %0 to %kind1",
+     (Type, const NominalTypeDecl *))
 ERROR(cannot_convert_assign_protocol,none,
       "value of type %0 does not conform to %1 in assignment",
       (Type, Type))
@@ -670,6 +679,9 @@ ERROR(expr_keypath_nonescapable_type,none,
 ERROR(expr_keypath_not_property,none,
       "%select{key path|dynamic key path member lookup}1 cannot refer to %kind0",
       (const ValueDecl *, bool))
+ERROR(expr_keypath_type_ref,none,
+      "%select{key path|dynamic key path member lookup}1 cannot refer to type %0",
+      (const ValueDecl *, bool))
 ERROR(expr_keypath_mutating_getter,none,
       "%select{key path|dynamic key path member lookup}1 cannot refer to %0, "
       "which has a mutating getter",
@@ -783,11 +795,11 @@ ERROR(expr_selector_not_objc,none,
       "Objective-C",
       (const ValueDecl *))
 NOTE(make_decl_objc,none,
-     "add '@objc' to expose this %0 to Objective-C",
-     (DescriptiveDeclKind))
+     "add '@objc' to expose this %kindonly0 to Objective-C",
+     (const ValueDecl *))
 NOTE(make_decl_objc_for_implementation,none,
-     "add '@objc' to implement an Objective-C %0",
-     (DescriptiveDeclKind))
+     "add '@objc' to implement an Objective-C %kindonly0",
+     (const Decl *))
 
 // Selectors-as-string-literals.
 WARNING(selector_literal_invalid,none,
@@ -810,9 +822,34 @@ ERROR(cannot_return_value_from_void_func,none,
 NOTE(add_return_type_note,none,
      "did you mean to add a return type?", ())
 
-ERROR(expect_compile_time_const,none,
+ERROR(expect_compile_time_literal,none,
       "expect a compile-time constant literal", ())
 
+ERROR(const_unsupported_enum_associated_value,none,
+      "enums with associated values not supported in a '@const' expression", ())
+ERROR(const_unsupported_operator,none,
+      "unsupported operator in a '@const' expression", ())
+ERROR(const_unsupported_type,none,
+      "unsupported type in a '@const' expression", ())
+ERROR(const_unsupported_type_expr,none,
+      "type expressions not supported in a '@const' expression", ())
+ERROR(const_unsupported_closure,none,
+      "closures not supported in a '@const' expression", ())
+ERROR(const_unsupported_keypath,none,
+      "keypaths not supported in a '@const' expression", ())
+ERROR(const_opaque_decl_ref,none,
+      "unable to resolve variable reference in a '@const' expression", ())
+ERROR(const_opaque_func_decl_ref,none,
+      "unable to resolve function reference in a '@const' expression", ())
+ERROR(const_non_convention_c_conversion,none,
+      "only 'convention(c)' function values are supported in a '@const' expression", ())
+ERROR(const_opaque_callee,none,
+      "unable to resolve callee in a '@const' expression", ())
+ERROR(const_non_const_param,none,
+      "reference to a non-'@const' parameter in a '@const' expression", ())
+ERROR(const_unknown_default,none,
+      "not supported in a '@const' expression", ())
+
 //------------------------------------------------------------------------------
 // MARK: Import Resolution
 //------------------------------------------------------------------------------
@@ -855,6 +892,10 @@ ERROR(serialization_failed,none,
 WARNING(can_import_invalid_swiftmodule,none,
         "canImport() evaluated to false due to invalid swiftmodule: %0", (StringRef))
 
+ERROR(map_os_version_from_textual_interface_failed,none,
+      "failed to map OS version from %0 to %1 in %2",
+      (StringRef, StringRef, StringRef))
+
 ERROR(serialization_load_failed,Fatal,
       "failed to load module '%0'", (StringRef))
 ERROR(module_interface_build_failed,Fatal,
@@ -922,9 +963,6 @@ ERROR(serialization_target_too_new_repl,none,
       "deployment target of %0 %3: %4",
       (StringRef, llvm::VersionTuple, Identifier, llvm::VersionTuple,
        StringRef))
-ERROR(serialization_non_ossa_module_incompatible, Fatal,
-      "cannot import non-OSSA module into an OSSA module",
-      (Identifier))
 
 ERROR(serialization_fatal,Fatal,
       "fatal error encountered while reading from module '%0'; "
@@ -932,11 +970,12 @@ ERROR(serialization_fatal,Fatal,
       (StringRef))
 
 ERROR(serialization_invalid_decl,Fatal,
-      "deserialized invalid declaration %0 (%1) in module '%2'",
-      (DeclName, DescriptiveDeclKind, StringRef))
+      "deserialized invalid declaration %0 (%kindonly0) in module %1",
+      (const Decl *, const ModuleDecl *))
 ERROR(serialization_allowing_invalid_decl,none,
-      "allowing deserialization of invalid declaration %0 (%1) in module '%2'",
-      (DeclName, DescriptiveDeclKind, StringRef))
+      "allowing deserialization of invalid declaration %0 (%kindonly0) in "
+      "module %1",
+      (const Decl *, const ModuleDecl *))
 ERROR(serialization_error_type,Fatal,
       "deserialized error type '%0' in module '%1'",
       (StringRef, StringRef))
@@ -1066,8 +1105,8 @@ ERROR(invalid_redecl_init,none,
       (const ValueDecl *, bool))
 ERROR(invalid_redecl_implicit,none,
       "invalid redeclaration of synthesized "
-      "%select{%0|implementation for protocol requirement}1 %2",
-      (DescriptiveDeclKind, bool, const ValueDecl *))
+      "%select{%kindonly0|implementation for protocol requirement}1 %2",
+      (const ValueDecl *, bool, const ValueDecl *))
 WARNING(invalid_redecl_swift5_warning,Deprecation,
         "redeclaration of %0 is deprecated and will be an error in Swift 5",
         (const ValueDecl *))
@@ -1185,7 +1224,7 @@ ERROR(imported_decl_is_wrong_kind_typealias,none,
 ERROR(ambiguous_decl_in_module,none,
       "ambiguous name %0 in module %1", (Identifier, Identifier))
 
-ERROR(module_not_testable,Fatal,
+GROUPED_ERROR(module_not_testable,ModuleNotTestable,Fatal,
       "module %0 was not compiled for testing", (Identifier))
 
 ERROR(module_not_compiled_for_private_import,none,
@@ -1211,11 +1250,13 @@ ERROR(module_not_compiled_with_library_evolution,none,
       "module %0 was not compiled with library evolution support; "
       "using it means binary compatibility for %1 can't be guaranteed",
       (Identifier, Identifier))
-WARNING(implementation_only_requires_library_evolution,none,
+GROUPED_WARNING(implementation_only_requires_library_evolution,
+        ImplementationOnlyDeprecated,none,
         "using '@_implementationOnly' without enabling library evolution "
         "for %0 may lead to instability during execution",
         (Identifier))
-WARNING(implementation_only_deprecated,none,
+GROUPED_WARNING(implementation_only_deprecated,
+        ImplementationOnlyDeprecated,none,
         "'@_implementationOnly' is deprecated, use 'internal import' instead",
         ())
 
@@ -1247,21 +1288,16 @@ REMARK(module_api_import_aliases,none,
        "%select{, which reexports definition from %2|}3",
        (const Decl *, ModuleDecl *, ModuleDecl *, bool))
 
-REMARK(dependency_scan_skip_module_invalid,none,
-       "module file '%0' skipped by the dependency scan because it is "
-       "incompatible with this Swift compiler: %1", (StringRef, StringRef))
-WARNING(skip_module_not_testable,none,
-        "ignore swiftmodule built without '-enable-testing': %0", (StringRef))
-WARNING(dependency_scan_module_incompatible, none,
-        "module file '%0' is incompatible with this Swift compiler: %1",
-        (StringRef, StringRef))
-
 REMARK(macro_loaded,none,
        "loaded macro implementation module %0 from "
        "%select{shared library '%2'|executable '%2'|"
        "compiler plugin server '%2' with shared library '%3'}1",
        (Identifier, unsigned, StringRef, StringRef))
 
+ERROR(resolved_macro_changed,none,
+      "resolved macro library '%0' failed verification: %1",
+      (StringRef, StringRef))
+
 REMARK(transitive_dependency_behavior,none,
        "%1 has %select{a required|an optional|an ignored}2 "
        "transitive dependency on '%0'",
@@ -1271,7 +1307,7 @@ REMARK(explicit_interface_build_skipped,none,
        "Skipped rebuilding module at %0 - up-to-date",
        (StringRef))
 
-WARNING(cannot_find_project_version,none,
+GROUPED_WARNING(cannot_find_module_version,ModuleVersionMissing,none,
         "cannot find user version number for%select{| Clang}1 module '%0';"
         " version number ignored", (StringRef, bool))
 
@@ -1389,10 +1425,10 @@ ERROR(did_not_call_function_value,none,
       ())
 ERROR(did_not_call_function,none,
       "function %0 was used as a property; add () to call it",
-      (Identifier))
+      (DeclBaseName))
 ERROR(did_not_call_method,none,
       "method %0 was used as a property; add () to call it",
-      (Identifier))
+      (DeclBaseName))
 
 ERROR(init_not_instance_member_use_assignment,none,
       "'init' is a member of the type; use assignment "
@@ -1549,6 +1585,9 @@ ERROR(missing_address_of,none,
 ERROR(missing_address_of_yield,none,
       "yielding mutable value of type %0 requires explicit '&'",
       (Type))
+ERROR(missing_address_of_return,none,
+      "returning mutable value from a mutate accessor requires explicit '&'",
+      ())
 ERROR(extraneous_address_of,none,
       "'&' may only be used to pass an argument to inout parameter",
       ())
@@ -1678,20 +1717,29 @@ NOTE(unbound_generic_parameter_explicit_fix,none,
      "explicitly specify the generic arguments to fix this issue", ())
 
 GROUPED_ERROR(invalid_dynamic_callable_type,DynamicCallable,none,
-      "@dynamicCallable attribute requires %0 to have either a valid "
+      "'@dynamicCallable' requires %0 to have either a valid "
       "'dynamicallyCall(withArguments:)' method or "
       "'dynamicallyCall(withKeywordArguments:)' method", (Type))
 GROUPED_ERROR(missing_dynamic_callable_kwargs_method,DynamicCallable,none,
-      "@dynamicCallable type %0 cannot be applied with keyword arguments; "
+      "'@dynamicCallable' type %0 cannot be applied with keyword arguments; "
       "missing 'dynamicCall(withKeywordArguments:)' method", (Type))
 
 ERROR(invalid_dynamic_member_lookup_type,none,
-      "@dynamicMemberLookup attribute requires %0 to have a "
+      "'@dynamicMemberLookup' requires %0 to have a "
       "'subscript(dynamicMember:)' method that accepts either "
       "'ExpressibleByStringLiteral' or a key path", (Type))
 NOTE(invalid_dynamic_member_subscript, none,
      "add an explicit argument label to this subscript to satisfy "
-     "the @dynamicMemberLookup requirement", ())
+     "the '@dynamicMemberLookup' requirement", ())
+ERROR(dynamic_member_lookup_candidate_inaccessible,none,
+      "'@dynamicMemberLookup' requires %0 to be as accessible as its "
+      "enclosing type",
+      (ValueDecl *))
+
+ERROR(too_many_dynamic_member_lookups,none,
+      "could not find member %0; exceeded the maximum number of nested "
+      "dynamic member lookups",
+      (DeclNameRef))
 
 ERROR(string_index_not_integer,none,
       "String must not be indexed with %0, it has variable size elements",
@@ -1709,7 +1757,7 @@ ERROR(c_function_pointer_from_generic_function,none,
       "a C function pointer cannot be formed from a reference to a generic "
       "function", ())
 ERROR(invalid_autoclosure_forwarding,none,
-      "add () to forward @autoclosure parameter", ())
+      "add () to forward '@autoclosure' parameter", ())
 ERROR(invalid_differentiable_function_conversion_expr,none,
       "a '@differentiable' function can only be formed from "
       "a reference to a 'func' or 'init' or a literal closure", ())
@@ -1743,9 +1791,9 @@ ERROR(nominal_type_not_attribute,none,
 
 ERROR(mutating_invalid_global_scope,none, "%0 is only valid on methods",
       (SelfAccessKind))
-ERROR(mutating_invalid_classes,none, "%0 is not valid on %1s in " 
+ERROR(mutating_invalid_classes,none, "%0 is not valid on %kindonly1s in "
       "%select{classes|class-bound protocols}2",
-      (SelfAccessKind, DescriptiveDeclKind, bool))
+      (SelfAccessKind, const FuncDecl *, bool))
 
 ERROR(functions_mutating_and_not,none,
       "method must not be declared both %0 and %1",
@@ -1764,25 +1812,25 @@ ERROR(transparent_in_classes_not_supported,none,
       "'@_transparent' attribute is not supported on declarations within classes", ())
 
 ERROR(iboutlet_nonobjc_class,none,
-      "@IBOutlet property cannot %select{have|be an array of}0 "
+      "'@IBOutlet' property cannot %select{have|be an array of}0 "
       "non-'@objc' class type %1", (bool, Type))
 ERROR(iboutlet_nonobjc_protocol,none,
-      "@IBOutlet property cannot %select{have|be an array of}0 "
+      "'@IBOutlet' property cannot %select{have|be an array of}0 "
       "non-'@objc' protocol type %1", (bool, Type))
 ERROR(iboutlet_nonobject_type,none,
-      "@IBOutlet property cannot %select{have|be an array of}0 "
+      "'@IBOutlet' property cannot %select{have|be an array of}0 "
       "non-object type %1", (bool, Type))
 ERROR(iboutlet_only_mutable,none,
-      "@IBOutlet attribute requires property to be mutable", ())
+      "'@IBOutlet' requires property to be mutable", ())
 ERROR(iboutlet_non_optional,none,
-      "@IBOutlet property has non-optional type %0", (Type))
+      "'@IBOutlet' property has non-optional type %0", (Type))
 NOTE(note_make_optional,none,
       "add '?' to form the optional type %0", (Type))
 NOTE(note_make_implicitly_unwrapped_optional,none,
       "add '!' to form an implicitly unwrapped optional", ())
 
 ERROR(invalid_ibdesignable_extension,none,
-      "@IBDesignable can only be applied to classes and extensions "
+      "'@IBDesignable' can only be applied to classes and extensions "
       "of classes", ())
 ERROR(attr_must_be_used_on_class_instance,none,
       "only class instance properties can be declared %0", (DeclAttribute))
@@ -1811,11 +1859,11 @@ NOTE(remove_async_add_task,none,
      "remove 'async' and wrap in 'Task' to use concurrency in %0",
      (const FuncDecl *))
 ERROR(no_objc_tagged_pointer_not_class_protocol,none,
-      "@unsafe_no_objc_tagged_pointer can only be applied to class protocols",
+      "'@unsafe_no_objc_tagged_pointer' can only be applied to class protocols",
       ())
 ERROR(swift_native_objc_runtime_base_not_on_root_class,none,
-      "@_swift_native_objc_runtime_base_not_on_root_class can only be applied "
-      "to root classes", ())
+      "'@_swift_native_objc_runtime_base_not_on_root_class' can only be "
+      "applied to root classes", ())
 
 WARNING(objc_implementation_early_spelling_deprecated,none,
         "'@_objcImplementation' is deprecated; use '@implementation' instead",
@@ -1836,12 +1884,12 @@ ERROR(objc_implementation_cannot_have_generics,none,
       "'@objc @implementation' cannot be used to implement %kind0",
       (ValueDecl *))
 ERROR(attr_objc_implementation_category_not_found,none,
-      "could not find category %0 on Objective-C class %1; make sure your "
-      "umbrella or bridging header imports the header that declares it",
+      "could not find category %0 on Objective-C class %1; make sure you "
+      "import the module or header that declares it",
       (Identifier, ValueDecl*))
 ERROR(attr_objc_implementation_func_not_found,none,
-      "could not find imported function '%0' matching %kind1; make sure your "
-      "umbrella or bridging header imports the header that declares it",
+      "could not find imported function '%0' matching %kind1; make sure you "
+      "import the module or header that declares it",
       (StringRef, ValueDecl*))
 NOTE(attr_objc_implementation_fixit_remove_category_name,none,
      "remove arguments to implement the main '@interface' for this class",
@@ -1888,13 +1936,13 @@ ERROR(member_of_objc_implementation_not_objc_or_final,none,
       "did you use the %kindonly0's Swift name?",
       (ValueDecl *, ValueDecl *))
 NOTE(fixit_add_private_for_objc_implementation,none,
-     "add 'private' or 'fileprivate' to define an Objective-C-compatible %0 "
-     "not declared in the header",
-     (DescriptiveDeclKind))
+     "add 'private' or 'fileprivate' to define an Objective-C-compatible "
+     "%kindonly0 not declared in the header",
+     (const ValueDecl *))
 NOTE(fixit_add_nonobjc_or_final_for_objc_implementation,none,
-     "add '%select{@nonobjc|final}1' to define a Swift-only %0"
+     "add '%select{@nonobjc|final}1' to define a Swift-only %kindonly0"
      "%select{| that cannot be overridden}1",
-     (DescriptiveDeclKind, /*suggestFinal=*/bool))
+     (const ValueDecl *, /*suggestFinal=*/bool))
 
 ERROR(objc_implementation_wrong_category,none,
       "%kind0 should be implemented in extension for "
@@ -1903,13 +1951,13 @@ ERROR(objc_implementation_wrong_category,none,
       (ValueDecl *, Identifier, Identifier))
 
 ERROR(objc_implementation_wrong_decl_kind,none,
-      "%kind0 does not match the %1 declared by the header",
-      (ValueDecl *, DescriptiveDeclKind))
+      "%kind0 does not match the %kindonly1 declared by the header",
+      (const ValueDecl *, const ValueDecl *))
 
 ERROR(objc_implementation_must_be_settable,none,
-      "%kind0 should be settable to match the settable %1 declared by the "
-      "header",
-      (ValueDecl *, DescriptiveDeclKind))
+      "%kind0 should be settable to match the settable %kindonly1 declared by "
+      "the header",
+      (const ValueDecl *, const ValueDecl *))
 
 ERROR(objc_implementation_type_mismatch,none,
       "%kind0 of type %1 does not match type %2 declared by the header",
@@ -1921,9 +1969,9 @@ ERROR(objc_implementation_sendability_mismatch,none,
       (ValueDecl *, Type, Type))
 
 ERROR(objc_implementation_required_attr_mismatch,none,
-      "%kind0 %select{should not|should}2 be 'required' to match %1 declared "
+      "%kind0 should%select{ not|}2 be 'required' to match %kindonly1 declared "
       "by the header",
-      (ValueDecl *, DescriptiveDeclKind, bool))
+      (const ValueDecl *, const ValueDecl *, bool))
 
 ERROR(objc_implementation_candidate_has_error_convention,none,
       "%kind0 does not match the declaration in the header because it throws an "
@@ -1977,14 +2025,23 @@ ERROR(objc_implementation_wrong_swift_name,none,
       "you mean %1?",
       (ObjCSelector, const ValueDecl *))
 
-ERROR(objc_implementation_missing_impl,none,
-      "extension for %select{main class interface|category %0}0 should "
-      "provide implementation for %kind1",
-      (Identifier, ValueDecl *))
+ERROR(objc_implementation_missing_impls,none,
+      "extension for %select{main class interface|category %0}0 does not "
+      "provide all required implementations",
+      (Identifier))
+NOTE(objc_implementation_missing_impls_fixit,none,
+     "add stub%s0 for missing '@implementation' requirement%s0",
+     (unsigned))
+NOTE(objc_implementation_missing_impl,none,
+     "missing %kind0",
+     (ValueDecl *))
+NOTE(objc_implementation_missing_impl_either,none,
+     "missing %kind0 or %1",
+     (ValueDecl *, ValueDecl *))
 
 ERROR(objc_implementation_class_or_instance_mismatch,none,
-      "%kind0 does not match %1 declared in header",
-      (ValueDecl *, DescriptiveDeclKind))
+      "%kind0 does not match %kindonly1 declared in header",
+      (const ValueDecl *, const ValueDecl *))
 
 ERROR(objc_implementation_multiple_matching_candidates,none,
       "found multiple implementations that could match %kind0 with selector %1",
@@ -2028,17 +2085,23 @@ WARNING(wrap_objc_implementation_will_become_error,none,
         (DiagnosticInfo *))
 
 ERROR(cdecl_not_at_top_level,none,
-      "@_cdecl can only be applied to global functions", ())
+      "%0 can only be applied to global functions", (DeclAttribute))
 ERROR(cdecl_empty_name,none,
-      "@_cdecl symbol name cannot be empty", ())
+      "%0 symbol name cannot be empty", (DeclAttribute))
 ERROR(cdecl_throws,none,
-      "raising errors from @_cdecl functions is not supported", ())
+      "raising errors from %0 functions is not supported", (DeclAttribute))
+ERROR(cdecl_incompatible_with_objc,none,
+      "cannot apply both '@c' and '@objc' to %kindonly0",
+      (const Decl *))
+ERROR(cdecl_feature_required,none,
+      "'@c' requires '-enable-experimental-feature CDecl'",
+      ())
 
 // @_used and @_section
 ERROR(section_linkage_markers_disabled,none,
       "attribute requires '-enable-experimental-feature SymbolLinkageMarkers'", ())
 ERROR(section_empty_name,none,
-      "@_section section name cannot be empty", ())
+      "'@_section' section name cannot be empty", ())
 
 // @_silgen_name and friends
 WARNING(reserved_runtime_symbol_name,none,
@@ -2048,23 +2111,24 @@ WARNING(reserved_runtime_symbol_name,none,
 
 // @_extern
 ERROR(attr_extern_experimental,none,
-      "@_extern requires '-enable-experimental-feature Extern'", ())
+      "'@_extern' requires '-enable-experimental-feature Extern'", ())
 ERROR(extern_not_at_top_level_func,none,
-      "@_extern attribute can only be applied to global functions", ())
+      "'@_extern' can only be applied to global functions", ())
 ERROR(extern_empty_c_name,none,
-      "expected non-empty C name in @_extern attribute", ())
+      "expected non-empty C name in '@_extern'", ())
 ERROR(extern_only_non_other_attr,none,
-      "@_extern attribute cannot be applied to an %0 declaration",
+      "'@_extern' cannot be applied to an %0 declaration",
       (DeclAttribute))
 WARNING(extern_c_maybe_invalid_name, none,
-        "C name '%0' may be invalid; explicitly specify the name in @_extern(c) to suppress this warning",
+        "C name '%0' may be invalid; explicitly specify the name in "
+        "'@_extern(c)' to suppress this warning",
         (StringRef))
 
 // @_staticExclusiveOnly
 ERROR(attr_static_exclusive_only_disabled,none,
       "attribute requires '-enable-experimental feature StaticExclusiveOnly'", ())
 ERROR(attr_static_exclusive_only_noncopyable,none,
-      "@_staticExclusiveOnly can only be applied to noncopyable types", ())
+      "'@_staticExclusiveOnly' can only be applied to noncopyable types", ())
 ERROR(attr_static_exclusive_only_let_only,none,
       "variable of type %0 must be declared with a 'let'", (Type))
 NOTE(attr_static_exclusive_only_type_nonmutating,none,
@@ -2076,13 +2140,20 @@ ERROR(attr_static_exclusive_only_mutating,none,
 ERROR(attr_static_exclusive_no_setters,none,
       "variable of type %0 must not have a setter", (Type))
 
+// @_manualOwnership
+ERROR(attr_manual_ownership_experimental,none,
+      "'@_manualOwnership' requires '-enable-experimental-feature ManualOwnership'", ())
+ERROR(attr_manual_ownership_noimplicitcopy,none,
+      "'@_noImplicitCopy' cannot be used with ManualOwnership", ())
+
 // @extractConstantsFromMembers
 ERROR(attr_extractConstantsFromMembers_experimental,none,
-      "@extractConstantsFromMembers requires '-enable-experimental-feature ExtractConstantsFromMembers'", ())
+      "'@extractConstantsFromMembers' requires "
+      "'-enable-experimental-feature ExtractConstantsFromMembers'", ())
 
 // @sensitive
 ERROR(attr_sensitive_experimental,none,
-      "@sensitive requires '-enable-experimental-feature Sensitive'", ())
+      "'@sensitive' requires '-enable-experimental-feature Sensitive'", ())
 
 ERROR(c_func_variadic, none,
       "cannot declare variadic argument %0 in %kind1",
@@ -2098,18 +2169,22 @@ ERROR(c_func_throws,none,
       "raising errors from C functions is not supported", ())
 
 ERROR(expose_wasm_not_at_top_level_func,none,
-      "@_expose attribute with 'wasm' can only be applied to global functions", ())
+      "'@_expose' with 'wasm' can only be applied to global "
+      "functions", ())
 
 ERROR(expose_only_non_other_attr,none,
-      "@_expose attribute cannot be applied to an '%0' declaration", (StringRef))
+      "'@_expose' cannot be applied to an '%0' declaration",
+      (StringRef))
 ERROR(expose_inside_unexposed_decl,none,
-      "@_expose attribute cannot be applied inside of unexposed declaration %0",
+      "'@_expose' cannot be applied inside of unexposed declaration %0",
       (const ValueDecl *))
+ERROR(expose_redundant_name_provided, none,
+      "'@_expose(!Cxx)' does not accept a name argument", ())
 ERROR(expose_invalid_name_pattern_init,none,
-      "invalid declaration name '%0' specified in an @_expose attribute; "
+      "invalid declaration name '%0' specified in '@_expose'; "
       "exposed initializer name must start with 'init'", (StringRef))
 ERROR(expose_unsupported_objc_decl_to_cxx,none,
-      "@objc %kind0 can not yet be exposed to C++", (ValueDecl *))
+      "'@objc' %kind0 can not yet be exposed to C++", (ValueDecl *))
 ERROR(expose_unsupported_async_decl_to_cxx,none,
       "async %kind0 can not be exposed to C++", (ValueDecl *))
 ERROR(expose_unsupported_actor_isolated_to_cxx,none,
@@ -2136,6 +2211,12 @@ ERROR(expose_nested_type_to_cxx,none,
       "nested %kind0 can not yet be represented in C++", (ValueDecl *))
 ERROR(expose_macro_to_cxx,none,
       "Swift macro can not yet be represented in C++", (ValueDecl *))
+WARNING(warn_unannotated_cxx_func_returning_frt, none,
+        "cannot infer the ownership of the returned value, annotate %0 with "
+        "either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED",
+        (const ValueDecl *))
+NOTE(note_unannotated_cxx_func_returning_frt, none, "%0 is defined here",
+     (const ValueDecl *))
 ERROR(unexposed_other_decl_in_cxx,none,
       "%kind0 is not yet exposed to C++", (ValueDecl *))
 ERROR(unsupported_other_decl_in_cxx,none,
@@ -2157,9 +2238,6 @@ ERROR(attr_only_at_non_generic_scope, none,
 ERROR(attr_only_on_static_properties, none,
       "properties with attribute %0 must be static", (DeclAttribute))
 
-ERROR(weak_unowned_in_embedded_swift, none,
-      "attribute %0 cannot be used in embedded Swift", (ReferenceOwnership))
-
 ERROR(access_control_in_protocol,none,
       "%0 modifier cannot be used in protocols", (DeclAttribute))
 NOTE(access_control_in_protocol_detail,none,
@@ -2182,8 +2260,8 @@ ERROR(access_control_setter_more,none,
 WARNING(access_control_setter_redundant,none,
       "'%select{private|fileprivate|internal|package|public|open}0(set)' modifier is "
       "redundant for %select{a private|a fileprivate|an internal|a package|a public|an open}2 "
-      "%1",
-      (AccessLevel, DescriptiveDeclKind, AccessLevel))
+      "%kindonly1",
+      (AccessLevel, const Decl *, AccessLevel))
 WARNING(access_control_ext_member_more,none,
     "'%select{%error|fileprivate|internal|package|public|open}0' modifier conflicts "
     "with extension's default access of "
@@ -2191,18 +2269,18 @@ WARNING(access_control_ext_member_more,none,
     (AccessLevel, AccessLevel))
 WARNING(access_control_ext_member_redundant,none,
     "'%select{%error|fileprivate|internal|package|public|%error}0' modifier is redundant "
-    "for %1 declared in %select{a private (equivalent to fileprivate)|a fileprivate"
+    "for %kindonly1 declared in %select{a private (equivalent to fileprivate)|a fileprivate"
     "|an internal|a package|a public|%error}2 extension",
-    (AccessLevel, DescriptiveDeclKind, AccessLevel))
+    (AccessLevel, const Decl *, AccessLevel))
 ERROR(access_control_ext_requirement_member_more,none,
-    "cannot declare %select{%error|a fileprivate|an internal|a package|a public|an open}0 %1 "
+    "cannot declare %select{%error|a fileprivate|an internal|a package|a public|an open}0 %kindonly1 "
     "in an extension with %select{private|fileprivate|internal|package|public|%error}2 "
     "requirements",
-    (AccessLevel, DescriptiveDeclKind, AccessLevel))
+    (AccessLevel, const Decl *, AccessLevel))
 ERROR(access_control_extension_more,none,
-      "extension of %select{private|fileprivate|internal|package|%error|%error}0 %1 cannot "
+      "extension of %select{private|fileprivate|internal|package|%error|%error}0 %kindonly1 cannot "
       "be declared %select{%error|fileprivate|internal|package|public|%error}2",
-      (AccessLevel, DescriptiveDeclKind, AccessLevel))
+      (AccessLevel, const NominalTypeDecl *, AccessLevel))
 ERROR(access_control_extension_open,none,
       "extensions cannot be declared 'open'; declare individual members as 'open' instead",
       ())
@@ -2220,11 +2298,11 @@ ERROR(access_control_requires_package_name, none,
 ERROR(invalid_decl_attribute,none,
       "'%0' attribute cannot be applied to this declaration", (DeclAttribute))
 ERROR(attr_invalid_on_decl_kind,none,
-      "'%0' attribute cannot be applied to %1 declarations",
-      (DeclAttribute, DescriptiveDeclKind))
+      "'%0' attribute cannot be applied to %kindonly1 declarations",
+      (DeclAttribute, const Decl *))
 ERROR(attr_invalid_in_context,none,
-      "'%0' attribute cannot be applied to declaration in %1",
-      (DeclAttribute, DescriptiveDeclKind))
+      "'%0' attribute cannot be applied to declaration in %kindonly1",
+      (DeclAttribute, const Decl *))
 ERROR(invalid_decl_modifier,none,
       "%0 modifier cannot be applied to this declaration", (DeclAttribute))
 ERROR(attribute_does_not_apply_to_type,none,
@@ -2232,7 +2310,7 @@ ERROR(attribute_does_not_apply_to_type,none,
 ERROR(optional_attribute_non_protocol,none,
       "'optional' can only be applied to protocol members", ())
 ERROR(optional_attribute_non_objc_protocol,none,
-      "'optional' can only be applied to members of an @objc protocol", ())
+      "'optional' can only be applied to members of an '@objc' protocol", ())
 ERROR(optional_attribute_missing_explicit_objc,none,
       "'optional' requirements are an Objective-C compatibility feature; add '@objc'",
       ())
@@ -2241,25 +2319,25 @@ ERROR(objcmembers_attribute_nonclass,none,
 ERROR(optional_attribute_initializer,none,
       "'optional' cannot be applied to an initializer", ())
 ERROR(unavailable_method_non_objc_protocol,none,
-      "protocol members can only be marked unavailable in an @objc protocol",
+      "protocol members can only be marked unavailable in an '@objc' protocol",
       ())
 ERROR(spi_available_malformed,none,
       "SPI available only supports introducing version on specific platform",
       ())
 ERROR(missing_in_class_init_1,none,
       "stored property %0 requires an initial value%select{| or should be "
-      "@NSManaged}1", (Identifier, bool))
+      "'@NSManaged'}1", (Identifier, bool))
 ERROR(missing_in_class_init_2,none,
       "stored properties %0 and %1 require initial values%select{| or should "
-      "be @NSManaged}2",
+      "be '@NSManaged'}2",
       (Identifier, Identifier, bool))
 ERROR(missing_in_class_init_3plus,none,
       "stored properties %0, %1, %select{and %2|%2, and others}3 "
-      "require initial values%select{| or should be @NSManaged}4",
+      "require initial values%select{| or should be '@NSManaged'}4",
       (Identifier, Identifier, Identifier, bool, bool))
 NOTE(requires_stored_property_inits_here,none,
      "%select{superclass|class}1 %0 requires all stored properties to have "
-     "initial values%select{| or use @NSManaged}2", (Type, bool, bool))
+     "initial values%select{| or use '@NSManaged'}2", (Type, bool, bool))
 ERROR(class_without_init,none,
       "%select{class|actor}0 %1 has no initializers", (bool, Type))
 NOTE(note_no_in_class_init_1,none,
@@ -2306,22 +2384,42 @@ ERROR(originally_definedin_must_not_before_available_version,none,
       "the OSs", ())
 
 WARNING(spi_preferred_over_spi_available,none,
-        "symbols that are @_spi_available on all platforms should use @_spi "
-        "instead", ())
+        "symbols that are '@_spi_available' on all platforms should use "
+        "'@_spi' instead", ())
 
 // Alignment attribute
 ERROR(alignment_not_power_of_two,none,
       "alignment value must be a power of two", ())
 
 // Dependency Scanning
-ERROR(dependency_scan_module_not_found, none, "Unable to find module dependency: '%0'", (StringRef))
+ERROR(dependency_scan_module_not_found, none, "unable to resolve module dependency: '%0'", (StringRef))
+
+GROUPED_ERROR(dependency_scan_module_not_found_on_specified_search_paths, MissingModuleOnKnownPaths, none,
+              "compilation search paths unable to resolve module dependency: '%0'", (StringRef))
+
 NOTE(unresolved_import_location,none,
      "also imported here", ())
 NOTE(dependency_as_imported_by_main_module,none,
      "a dependency of main module '%0'", (StringRef))
 NOTE(dependency_as_imported_by, none,
      "a dependency of %select{Swift|Clang}2 module '%0': '%1'", (StringRef, StringRef, bool))
-ERROR(clang_dependency_scan_error, none, "Clang dependency scanner failure: %0", (StringRef))
+NOTE(inherited_search_path_resolves_module,none,
+     "'%0' can be found using a search path that was specified when building module '%1' ('%2'). "
+     "This search path was not explicitly specified on the current compilation", (StringRef, StringRef, StringRef))
+
+ERROR(dependency_scan_compatible_swift_module_not_found, none,
+      "unable to resolve Swift module dependency to a compatible module: '%0'",
+      (StringRef))
+NOTE(dependency_scan_incompatible_module_found,none,
+     "found incompatible module '%0': %1", (StringRef, StringRef))
+
+WARNING(dependency_scan_module_incompatible, none,
+        "module file '%0' is incompatible with this Swift compiler: %1",
+        (StringRef, StringRef))
+
+ERROR(clang_dependency_scan_error, none, "clang dependency scanning failure: %0", (StringRef))
+
+ERROR(clang_header_dependency_scan_error, none, "bridging header dependency scanning failure: %0", (StringRef))
 
 // Enum annotations
 ERROR(indirect_case_without_payload,none,
@@ -2336,8 +2434,8 @@ ERROR(getset_init,none,
       "variable with getter/setter cannot have an initial value", ())
 
 ERROR(effectful_not_representable_objc,none,
-      "%0 with 'throws' or 'async' is not representable in Objective-C",
-      (DescriptiveDeclKind))
+      "%kindonly0 with 'throws' or 'async' is not representable in Objective-C",
+      (const AbstractStorageDecl *))
 
 ERROR(unimplemented_static_var,none,
       "%select{ERROR|static|class}1 stored properties not supported"
@@ -2571,10 +2669,10 @@ WARNING(function_type_usable_from_inline_warn,none,
         (unsigned, bool, bool))
 
 ERROR(spi_attribute_on_non_public,none,
-      "%select{private|fileprivate|internal|package|%error|%error}0 %1 "
+      "%select{private|fileprivate|internal|package|%error|%error}0 %kindonly1 "
       "cannot be declared '@_spi' because only public and open "
       "declarations can be '@_spi'",
-      (AccessLevel, DescriptiveDeclKind))
+      (AccessLevel, const ValueDecl *))
 ERROR(spi_attribute_on_protocol_requirement,none,
       "protocol requirement %0 cannot be declared '@_spi' without "
       "a default implementation in a protocol extension",
@@ -2608,13 +2706,13 @@ NOTE(module_imported_here,none,
 NOTE(decl_import_via_here,none,
      "%kind0 imported as "
      "'%select{private|fileprivate|internal|package|%ERROR|%ERROR}1' "
-     "from %2 here",
-     (const Decl *, AccessLevel, const ModuleDecl*))
+     "from %select{%2 here|bridging header}3",
+     (const Decl *, AccessLevel, const ModuleDecl*, bool))
 NOTE(decl_import_via_local,none,
      "%kind0 is imported by this file as "
      "'%select{private|fileprivate|internal|package|%ERROR|%ERROR}1' "
-     "from %2",
-     (const Decl *, AccessLevel, const ModuleDecl*))
+     "from %select{%2|bridging header}3",
+     (const Decl *, AccessLevel, const ModuleDecl*, bool))
 
 // Opaque return types
 ERROR(opaque_type_invalid_constraint,none,
@@ -2687,10 +2785,6 @@ NOTE(invalid_extension_rewrite,none,
 ERROR(cannot_extend_nominal,none,
       "cannot extend %kind0", (const NominalTypeDecl *))
 
-ERROR(retroactive_not_in_extension_inheritance_clause,none,
-      "'retroactive' attribute only applies in inheritance clauses in "
-      "extensions", ())
-
 ERROR(retroactive_attr_does_not_apply,none,
       "'retroactive' attribute does not apply; %0 is declared in "
       "%select{the same package|this module}1",
@@ -2740,16 +2834,16 @@ NOTE(non_sendable_nominal,none,
 NOTE(add_nominal_sendable_conformance,none,
      "consider making %kind0 conform to the 'Sendable' protocol",
      (const ValueDecl *))
-NOTE(add_generic_parameter_sendable_conformance,none,
-     "consider making generic parameter %0 conform to the 'Sendable' protocol",
-     (Type))
+NOTE(add_generic_parameter_conformance,none,
+     "consider making generic parameter %0 conform to the %1 protocol",
+     (Type, ProtocolDecl *))
 WARNING(add_predates_concurrency_import,none,
      "add '@preconcurrency' to %select{suppress|treat}0 "
      "'Sendable'-related %select{warnings|errors}0 from module %1"
      "%select{| as warnings}0", (bool, Identifier))
 GROUPED_WARNING(remove_predates_concurrency_import,PreconcurrencyImport,
                 DefaultIgnore,
-                "'@preconcurrency' attribute on module %0 has no effect", (Identifier))
+                "'@preconcurrency' on module %0 has no effect", (Identifier))
 WARNING(remove_public_import,none,
         "public import of %0 was not used in public declarations or inlinable code",
         (Identifier))
@@ -2759,9 +2853,6 @@ WARNING(remove_package_import,none,
 WARNING(public_decl_needs_sendable,none,
         "public %kind0 does not specify whether it is 'Sendable' or not",
         (const ValueDecl *))
-NOTE(explicit_unchecked_sendable,none,
-     "add '@unchecked Sendable' conformance to %kind0 if this type manually implements concurrency safety",
-     (const ValueDecl *))
 NOTE(explicit_disable_sendable,none,
      "make %kind0 explicitly non-Sendable to suppress this warning",
      (const ValueDecl *))
@@ -2877,11 +2968,11 @@ ERROR(non_class_cannot_conform_to_class_protocol,none,
       "non-class type %0 cannot conform to class protocol %1",
       (Type, Type))
 ERROR(cf_class_cannot_conform_to_objc_protocol,none,
-      "Core Foundation class %0 cannot conform to @objc protocol %1 because "
+      "Core Foundation class %0 cannot conform to '@objc' protocol %1 because "
       "Core Foundation types are not classes in Objective-C",
       (Type, Type))
 ERROR(objc_runtime_visible_cannot_conform_to_objc_protocol,none,
-      "class %0 cannot conform to @objc protocol %1 because "
+      "class %0 cannot conform to '@objc' protocol %1 because "
       "the class is only visible via the Objective-C runtime",
       (Type, Type))
 ERROR(objc_generics_cannot_conditionally_conform,none,
@@ -2889,13 +2980,13 @@ ERROR(objc_generics_cannot_conditionally_conform,none,
       "the type uses the Objective-C generics model",
       (Type, Type))
 ERROR(objc_protocol_cannot_have_conditional_conformance,none,
-      "type %0 cannot conditionally conform to @objc protocol %1 because "
+      "type %0 cannot conditionally conform to '@objc' protocol %1 because "
       "Objective-C does not support conditional conformances",
       (Type, Type))
 ERROR(objc_protocol_in_generic_extension,none,
       "conformance of "
       "%select{class from generic context|generic class}0 "
-      "%1 to @objc protocol %2 cannot be in an extension",
+      "%1 to '@objc' protocol %2 cannot be in an extension",
       (bool, Type, Type))
 ERROR(conditional_conformances_cannot_imply_conformances,none,
       "conditional conformance of type %0 to protocol %1 does not imply conformance to "
@@ -2994,12 +3085,15 @@ ERROR(type_witness_objc_generic_parameter,none,
       "used for associated type %3 of protocol %4",
       (Type, Type, bool, const AssociatedTypeDecl *, const ProtocolDecl *))
 NOTE(witness_fix_access,none,
-     "mark the %0 as '%select{%error|fileprivate|internal|package|public|%error}1' to "
-     "satisfy the requirement", (DescriptiveDeclKind, AccessLevel))
+     "mark the %kindonly0 as "
+     "'%select{%error|fileprivate|internal|package|public|%error}1' to "
+     "satisfy the requirement",
+     (const ValueDecl *, AccessLevel))
 NOTE(witness_move_to_another_extension,none,
-     "move the %0 to another extension where it can be declared "
+     "move the %kindonly0 to another extension where it can be declared "
      "'%select{%error|%error|internal|package|public|%error}1' to "
-     "satisfy the requirement", (DescriptiveDeclKind, AccessLevel))
+     "satisfy the requirement",
+     (const ValueDecl *, AccessLevel))
 WARNING(assoc_type_default_conformance_failed,none,
         "default type %0 for associated type %1 does not satisfy constraint "
         "%2: %3", (Type, const AssociatedTypeDecl *, Type, Type))
@@ -3208,9 +3302,9 @@ NOTE(protocol_conformance_here,none,
 NOTE(declared_protocol_conformance_here,none,
      "%select{%0 inherits conformance to protocol %2 from superclass|"
      "%0 declares conformance to protocol %2|"
-     "%0 implicitly conforms to protocol %2 (via conformance to %3)|"
-     "%0 implicitly conforms to protocol %2 |"
-     "conformance to %2 generated by macro }1 here",
+     "conformance to %2 generated by macro|"
+     "%0 implicitly conforms to protocol %2|"
+     "%0 implicitly conforms to protocol %2 (via conformance to %3)}1 here",
      (Type, unsigned, Identifier, Identifier))
 
 ERROR(witness_unavailable,none,
@@ -3290,7 +3384,7 @@ ERROR(typealias_outside_of_protocol,none,
       (DeclNameRef, Type))
 
 ERROR(objc_protocol_inherits_non_objc_protocol,none,
-      "@objc protocol %0 cannot refine non-@objc protocol %1", (Type, Type))
+      "'@objc' protocol %0 cannot refine non-'@objc' protocol %1", (Type, Type))
 
 ERROR(protocol_where_clause_self_requirement,none,
       "constraint with subject type of 'Self' is not supported; "
@@ -3328,6 +3422,9 @@ ERROR(invalid_shape_requirement,none,
 ERROR(unsupported_same_element,none,
       "same-element requirements are not yet supported",
       ())
+ERROR(unsupported_pack_same_type,none,
+      "same-type requirements between packs and concrete types are not yet supported",
+      ())
 
 ERROR(requires_generic_params_made_equal,none,
       "same-type requirement makes generic parameters %0 and %1 equivalent",
@@ -3370,11 +3467,12 @@ WARNING(typealias_override_associated_type,none,
         (Identifier, Type))
 WARNING(associated_type_override_typealias,none,
         "associated type %0 is redundant with type %0 declared in inherited "
-        "%1 %2", (Identifier, DescriptiveDeclKind, Type))
+        "%kind1",
+        (Identifier, const NominalTypeDecl *))
 
 ERROR(requirement_machine_completion_failed,none,
       "cannot build rewrite system for %select{generic signature|protocol}0; "
-      "%select{%error|rule count|rule length|concrete nesting}1 limit exceeded",
+      "%select{%error|rule count|rule length|concrete type nesting|concrete type size|concrete type difference}1 limit exceeded",
       (unsigned, unsigned))
 NOTE(requirement_machine_completion_rule,none,
      "failed rewrite rule is %0", (StringRef))
@@ -3384,30 +3482,30 @@ ERROR(associated_type_objc,none,
       (Identifier, Identifier))
 
 ERROR(generic_param_access,none,
-      "%0 %select{must be declared %select{"
+      "%kindonly0 %select{must be declared %select{"
       "%select{private|fileprivate|internal|package|%error|%error}3|private or fileprivate}4"
       "|cannot be declared "
       "%select{in this context|fileprivate|internal|package|public|open}2}1 "
       "because its generic %select{parameter|requirement}5 uses "
       "%select{a private|a fileprivate|an internal|a package|an '@_spi'|an '@_spi'}3 type",
-      (DescriptiveDeclKind, bool, AccessLevel, AccessLevel, bool, bool))
+      (const Decl *, bool, AccessLevel, AccessLevel, bool, bool))
 WARNING(generic_param_access_warn,none,
-        "%0 %select{should be declared "
+        "%kindonly0 %select{should be declared "
         "%select{private|fileprivate|internal|package|%error|%error}3"
         "|should not be declared %select{in this context|fileprivate|internal|package|public|open}2}1 "
         "because its generic %select{parameter|requirement}5 uses "
         "%select{a private|a fileprivate|an internal|a package|an '@_spi'|an '@_spi'}3 type",
-        (DescriptiveDeclKind, bool, AccessLevel, AccessLevel, bool, bool))
+        (const Decl *, bool, AccessLevel, AccessLevel, bool, bool))
 ERROR(generic_param_usable_from_inline,none,
       "type referenced from a "
-      "generic %select{parameter|requirement}1 of a '@usableFromInline' %0 "
-      "must be '@usableFromInline' or public",
-      (DescriptiveDeclKind, bool))
+      "generic %select{parameter|requirement}1 of a '@usableFromInline' "
+      "%kindonly0 must be '@usableFromInline' or public",
+      (const Decl *, bool))
 WARNING(generic_param_usable_from_inline_warn,none,
         "type referenced from a "
-        "generic %select{parameter|requirement}1 of a '@usableFromInline' %0 "
-        "should be '@usableFromInline' or public",
-        (DescriptiveDeclKind, bool))
+        "generic %select{parameter|requirement}1 of a '@usableFromInline' "
+        "%kindonly0 should be '@usableFromInline' or public",
+        (const Decl *, bool))
 
 ERROR(override_multiple_decls_base,none,
       "declaration %0 cannot override more than one superclass declaration",
@@ -3425,7 +3523,7 @@ NOTE(overridden_near_match_here,none,
      "potential overridden %kind0 here",
       (const ValueDecl *))
 ERROR(override_decl_extension,none,
-      "%select{|non-@objc}0 %kind2 %select{"
+      "%select{|non-'@objc'}0 %kind2 %select{"
       "is declared in extension of %3 and cannot be overridden|"
       "declared in %3 cannot be overridden from extension}1",
       (bool, bool, const ValueDecl *, DeclName))
@@ -3445,13 +3543,17 @@ ERROR(multiple_override,none,
 NOTE(multiple_override_prev,none,
      "%0 previously overridden here", (DeclName))
 
-ERROR(override_unavailable, none,
-      "cannot override %0 which has been marked unavailable%select{|: %1}1",
-      (DeclBaseName, StringRef))
+ERROR(cannot_override_unavailable, none,
+      "cannot override %base0 which has been marked unavailable%select{|: %1}1",
+      (ValueDecl *, StringRef))
 NOTE(suggest_removing_override, none,
      "remove 'override' modifier to declare a new %0",
      (DeclBaseName))
 
+ERROR(override_unavailable, none,
+      "cannot override %base0 with a declaration that is marked unavailable",
+      (ValueDecl *))
+
 ERROR(override_less_available,none,
       "overriding %base0 must be as available as declaration it overrides",
       (ValueDecl *))
@@ -3462,13 +3564,13 @@ ERROR(override_let_property,none,
 
 
 ERROR(override_not_accessible,none,
-      "%select{|setter of }0overriding %1 must be as accessible as "
+      "%select{|setter of }0overriding %kindonly1 must be as accessible as "
       "%select{its enclosing type|the declaration it overrides}2",
-      (bool, DescriptiveDeclKind, bool))
+      (bool, const ValueDecl *, bool))
 
 ERROR(override_of_non_open,none,
-      "overriding non-open %0 outside of its defining module",
-      (DescriptiveDeclKind))
+      "overriding non-open %kindonly0 outside of its defining module",
+      (const ValueDecl *))
 
 ERROR(method_does_not_override,none,
       "method does not override any method from its %select{parent protocol|superclass}0", (bool))
@@ -3492,8 +3594,8 @@ NOTE(subscript_override_here,none,
 NOTE(convenience_init_override_here,none,
      "attempt to override convenience initializer here", ())
 NOTE(override_type_mismatch_with_fixits,none,
-     "type does not match superclass %0 with type %1",
-     (DescriptiveDeclKind, Type))
+     "type does not match superclass %kindonly0 with type %1",
+     (const ValueDecl *, Type))
 NOTE(override_type_mismatch_with_fixits_init,none,
      "type does not match superclass initializer with %select{no arguments|argument %1|arguments %1}0",
      (unsigned, Type))
@@ -3529,34 +3631,34 @@ ERROR(override_class_declaration_in_extension,none,
       "cannot override a non-dynamic class declaration from an extension",
       ())
 ERROR(override_with_more_effects,none,
-      "cannot override non-%1 %0 with %1 %0",
-      (DescriptiveDeclKind, StringRef))
+      "cannot override non-%1 %kindonly0 with %1 %kindonly0",
+      (const ValueDecl *, StringRef))
 ERROR(override_typed_throws,none,
-      "%0 that throws %1 cannot override one that throws %2",
-      (DescriptiveDeclKind, Type, Type))
+      "%kindonly0 that throws %1 cannot override one that throws %2",
+      (const AbstractFunctionDecl *, Type, Type))
 ERROR(override_throws_objc,none,
-      "overriding a throwing @objc %select{method|initializer}0 with "
+      "overriding a throwing '@objc' %select{method|initializer}0 with "
       "a non-throwing %select{method|initializer}0 is not supported", (bool))
 ERROR(satisfy_throws_objc,none,
-      "satisfying a throwing @objc %select{method|initializer}0 with "
+      "satisfying a throwing '@objc' %select{method|initializer}0 with "
       "a non-throwing %select{method|initializer}0 is not supported", (bool))
 
 ERROR(override_optional_mismatch,none,
-      "cannot override %0 %select{parameter|index}1 of type %2 with "
+      "cannot override %kindonly0 %select{parameter|index}1 of type %2 with "
       "non-optional type %3",
-      (DescriptiveDeclKind, bool, Type, Type))
+      (const ValueDecl *, bool, Type, Type))
 ERROR(override_optional_result_mismatch,none,
-      "cannot override %0 %select{result|element}1 type %2 with "
+      "cannot override %kindonly0 %select{result|element}1 type %2 with "
       "optional type %3",
-      (DescriptiveDeclKind, bool, Type, Type))
+      (const ValueDecl *, bool, Type, Type))
 WARNING(override_unnecessary_IUO,none,
-      "overriding %0 parameter of type %1 with implicitly unwrapped optional "
-      "type %2",
-      (DescriptiveDeclKind, Type, Type))
+      "overriding %kindonly0 parameter of type %1 with implicitly unwrapped "
+      "optional type %2",
+      (const ValueDecl *, Type, Type))
 WARNING(override_unnecessary_result_IUO,none,
-      "overriding %0 optional result type %1 with implicitly unwrapped "
+      "overriding %kindonly0 optional result type %1 with implicitly unwrapped "
       "optional type %2",
-      (DescriptiveDeclKind, Type, Type))
+      (const ValueDecl *, Type, Type))
 NOTE(override_unnecessary_IUO_remove,none,
      "remove '!' to make the parameter required", ())
 NOTE(override_unnecessary_IUO_use_strict,none,
@@ -3573,7 +3675,8 @@ ERROR(override_mutable_covariant_subscript,none,
 ERROR(static_decl_already_final,none,
       "static declarations are already final", ())
 ERROR(open_decl_cannot_be_final,none,
-      "%0 cannot be declared both 'final' and 'open'", (DescriptiveDeclKind))
+      "%kindonly0 cannot be declared both 'final' and 'open'",
+      (const Decl *))
 ERROR(implicitly_final_cannot_be_open,none,
       "%select{'let' properties|members of 'final' classes|"
       "static declarations}0 are implicitly 'final'; use 'public' instead of "
@@ -3601,8 +3704,6 @@ ERROR(inheritance_from_non_protocol,none,
   "inheritance from non-protocol type %0", (Type))
 ERROR(inheritance_from_anyobject,none,
   "only protocols can inherit from 'AnyObject'", ())
-ERROR(inheritance_from_parameterized_protocol,none,
-  "cannot inherit from protocol type with generic argument %0", (Type))
 ERROR(superclass_not_first,none,
   "superclass %0 must appear first in the inheritance clause", (Type))
 ERROR(superclass_not_open,none,
@@ -3705,9 +3806,9 @@ ERROR(enum_with_raw_type_case_with_argument,none,
 NOTE(enum_raw_type_here,none,
      "declared raw type %0 here", (Type))
 ERROR(objc_enum_no_raw_type,none,
-      "'@objc' enum must declare an integer raw type", ())
+      "'%0' enum must declare an integer raw type", (DeclAttribute))
 ERROR(objc_enum_raw_type_not_integer,none,
-      "'@objc' enum raw type %0 is not an integer type", (Type))
+      "'%0' enum raw type %1 is not an integer type", (DeclAttribute, Type))
 ERROR(enum_non_integer_raw_value_auto_increment,none,
       "enum case must declare a raw value when the preceding raw value is not an integer", ())
 ERROR(enum_non_integer_convertible_raw_type_no_value,none,
@@ -3715,9 +3816,6 @@ ERROR(enum_non_integer_convertible_raw_type_no_value,none,
       "expressible by integer or string literal", ())
 ERROR(enum_raw_value_not_unique,none,
       "raw value for enum case is not unique", ())
-ERROR(enum_raw_value_magic_literal,none,
-      "use of '%0' literal as raw value for enum case is not supported",
-      (StringRef))
 NOTE(enum_raw_value_used_here,none,
      "raw value previously used here", ())
 NOTE(enum_raw_value_incrementing_from_here,none,
@@ -3732,13 +3830,15 @@ ERROR(decl_from_hidden_module,none,
       "as result builder here|"
       "in an extension with public or '@usableFromInline' members|"
       "in an extension with conditional conformances|"
-      "in a public or '@usableFromInline' conformance}1; "
+      "in a public or '@usableFromInline' conformance|"
+      "in an '@available' attribute here}1; "
       "%select{%2 has been imported as implementation-only|"
       "it is an SPI imported from %2|"
       "it is SPI|"
       "%2 was imported for SPI only|"
       "%2 was not imported by this file|"
       "C++ types from imported module %2 do not support library evolution|"
+      "it was imported via the internal bridging header|"
       "%2 was not imported publicly}3",
       (const Decl *, unsigned, Identifier, unsigned))
 ERROR(typealias_desugars_to_type_from_hidden_module,none,
@@ -3747,13 +3847,15 @@ ERROR(typealias_desugars_to_type_from_hidden_module,none,
       "as result builder here|"
       "in an extension with public or '@usableFromInline' members|"
       "in an extension with conditional conformance|"
-      "in a public or '@usableFromInline' conformance}3 "
+      "in a public or '@usableFromInline' conformance|"
+      "<<ERROR>>}3 "
       "because %select{%4 has been imported as implementation-only|"
       "it is an SPI imported from %4|"
       "<<ERROR>>|"
       "%4 was imported for SPI only|"
       "%4 was not imported by this file|"
       "C++ types from imported module %4 do not support library evolution|"
+      "it was imported via the internal bridging header|"
       "%4 was not imported publicly}5",
       (const TypeAliasDecl *, StringRef, StringRef, unsigned, Identifier, unsigned))
 ERROR(conformance_from_implementation_only_module,none,
@@ -3761,13 +3863,14 @@ ERROR(conformance_from_implementation_only_module,none,
       "as result builder here|"
       "in an extension with public or '@usableFromInline' members|"
       "in an extension with conditional conformances|"
-      "<<ERROR>>}2; "
+      "<<ERROR>>|<<ERROR>>}2; "
       "%select{%3 has been imported as implementation-only|"
       "the conformance is declared as SPI in %3|"
       "the conformance is declared as SPI|"
       "%3 was imported for SPI only|"
       "%3 was not imported by this file|"
       "C++ types from imported module %3 do not support library evolution|"
+      "it was imported via the internal bridging header|"
       "%3 was not imported publicly}4",
       (Type, Identifier, unsigned, Identifier, unsigned))
 NOTE(assoc_conformance_from_implementation_only_module,none,
@@ -3826,11 +3929,13 @@ ERROR(implementation_only_override_changed_type,none,
       "'@_implementationOnly' override must have the same type as the "
       "declaration it overrides (%0)", (Type))
 ERROR(implementation_only_override_without_attr,none,
-      "override of '@_implementationOnly' %0 should also be declared "
-      "'@_implementationOnly'", (DescriptiveDeclKind))
+      "override of '@_implementationOnly' %kindonly0 should also be declared "
+      "'@_implementationOnly'",
+      (const ValueDecl *))
 ERROR(implementation_only_override_import_without_attr,none,
-      "override of %0 imported as implementation-only must be declared "
-      "'@_implementationOnly'", (DescriptiveDeclKind))
+      "override of %kindonly0 imported as implementation-only must be declared "
+      "'@_implementationOnly'",
+      (const ValueDecl *))
 
 ERROR(import_attr_conflict,none,
       "%0 inconsistently imported with %1",
@@ -3959,8 +4064,8 @@ NOTE(missing_member_type_conformance_prevents_synthesis, none,
      "of %3 to %2",
      (unsigned, Type, Type, Type))
 NOTE(automatic_protocol_synthesis_unsupported,none,
-    "automatic synthesis of '%0' is not supported for %1 declarations",
-    (StringRef, DescriptiveDeclKind))
+    "automatic synthesis of %0 is not supported for %kindonly1 declarations",
+    (const ProtocolDecl *, const NominalTypeDecl *))
 NOTE(comparable_synthesis_raw_value_not_allowed, none,
      "enum declares raw type %0, preventing synthesized conformance of %1 to %2", 
      (Type, Type, Type))
@@ -4032,10 +4137,11 @@ ERROR(attr_contains_multiple_versions_for_platform,none,
       "'%0' contains multiple versions for %1", (DeclAttribute, StringRef))
 
 ERROR(override_final,none,
-      "%0 overrides a 'final' %1", (DescriptiveDeclKind, DescriptiveDeclKind))
+      "%kindonly0 overrides a 'final' %kindonly1",
+      (const ValueDecl *, const ValueDecl *))
 
 ERROR(override_static,none,
-      "cannot override %0", (DescriptiveDeclKind))
+      "cannot override %kindonly0", (const ValueDecl *))
 
 ERROR(member_cannot_be_final,none,
       "only classes and class members may be marked with 'final'",
@@ -4046,16 +4152,16 @@ ERROR(final_not_allowed_here,none,
       "subscripts", ())
 
 ERROR(attr_incompatible_with_non_final,none,
-      "'%0' cannot be applied to a non-final %1",
-      (DeclAttribute, DescriptiveDeclKind))
+      "'%0' cannot be applied to a non-final %kindonly1",
+      (DeclAttribute, const ValueDecl *))
 
 ERROR(attr_incompatible_with_override,none,
       "'%0' cannot be combined with 'override'",
       (DeclAttribute))
 
 ERROR(attr_incompatible_with_objc,none,
-      "'%0' must not be used on an '@objc' %1",
-      (DeclAttribute, DescriptiveDeclKind))
+      "'%0' must not be used on an '@objc' %kindonly1",
+      (DeclAttribute, const ValueDecl *))
 
 ERROR(attr_unusable_in_protocol,none,
       "'%0' cannot be used inside a protocol declaration",
@@ -4083,19 +4189,19 @@ ERROR(isolation_in_inherits_executor,none,
       "#isolation%select{| (introduced by a default argument)}0 cannot be used "
       "within an '@_unsafeInheritExecutor' function", (bool))
 ERROR(unsafe_inherits_executor_deprecated,none,
-        "@_unsafeInheritExecutor attribute is deprecated; consider an "
+        "'@_unsafeInheritExecutor' is deprecated; consider an "
         "'isolated' parameter defaulted to '#isolation' instead", ())
 
 ERROR(lifetime_invalid_global_scope,none, "%0 is only valid on methods",
       (DeclAttribute))
 ERROR(eagermove_and_lexical_combined,none,
-      "@_eagerMove and @_noEagerMove attributes are alternate styles of lifetimes "
+      "'@_eagerMove' and '@_noEagerMove' are alternate styles of lifetimes "
       "and can't be combined", ())
 ERROR(eagermove_and_noncopyable_combined,none,
-      "@_eagerMove cannot be applied to NonCopyable types", ())
+      "'@_eagerMove' cannot be applied to NonCopyable types", ())
 
 ERROR(autoclosure_function_type,none,
-      "@autoclosure attribute only applies to function types",
+      "'@autoclosure' only applies to function types",
       ())
 
 ERROR(invalid_autoclosure_and_convention_attributes,none,
@@ -4103,10 +4209,11 @@ ERROR(invalid_autoclosure_and_convention_attributes,none,
       (StringRef))
 
 ERROR(autoclosure_function_input_nonunit,none,
-      "argument type of @autoclosure parameter must be '()'", ())
+      "argument type of '@autoclosure' parameter must be '()'", ())
 
 ERROR(escaping_non_function_parameter,none,
-      "@escaping attribute may only be used in function parameter position", ())
+      "'@escaping' may only be used in function parameter position",
+      ())
 
 ERROR(escaping_inout_parameter,none,
       "inout expression is implicitly escaping", ())
@@ -4127,34 +4234,34 @@ ERROR(instancemember_compilerinitialized,none,
 
 // @_nonEphemeral attribute
 ERROR(non_ephemeral_non_pointer_type,none,
-      "@_nonEphemeral attribute only applies to pointer types", ())
+      "'@_nonEphemeral' only applies to pointer types", ())
 
 // NSManaged attribute
 ERROR(attr_NSManaged_not_instance_member,none,
-      "@NSManaged only allowed on an instance property or method", ())
+      "'@NSManaged' only allowed on an instance property or method", ())
 ERROR(attr_NSManaged_not_stored,none,
-      "@NSManaged not allowed on %select{computed|observing|addressed}0 "
+      "'@NSManaged' not allowed on %select{computed|observing|addressed}0 "
       "properties", (unsigned))
 ERROR(attr_NSManaged_let_property,none,
-      "@NSManaged not allowed on a 'let' property", ())
+      "'@NSManaged' not allowed on a 'let' property", ())
 ERROR(attr_NSManaged_initial_value,none,
-      "@NSManaged property cannot have an initial value", ())
+      "'@NSManaged' property cannot have an initial value", ())
 ERROR(attr_NSManaged_NSCopying,none,
-      "@NSManaged property cannot also be marked @NSCopying", ())
+      "'@NSManaged' property cannot also be marked '@NSCopying'", ())
 ERROR(attr_NSManaged_method_body,none,
-      "@NSManaged method cannot have a body; it must be provided at runtime",())
+      "'@NSManaged' method cannot have a body; it must be provided at runtime",())
 
 
 // NSCopying attribute
 ERROR(nscopying_only_on_class_properties,none,
-      "@NSCopying may only be used on properties in classes",
+      "'@NSCopying' may only be used on properties in classes",
       ())
 ERROR(nscopying_only_mutable,none,
-      "@NSCopying requires property to be mutable", ())
+      "'@NSCopying' requires property to be mutable", ())
 ERROR(nscopying_only_stored_property,none,
-      "@NSCopying is only valid on stored properties", ())
+      "'@NSCopying' is only valid on stored properties", ())
 ERROR(nscopying_doesnt_conform,none,
-      "@NSCopying is only valid with types that conform to"
+      "'@NSCopying' is only valid with types that conform to"
       " the NSCopying protocol", ())
 
 // UIApplicationMain/NSApplicationMain attribute
@@ -4181,7 +4288,7 @@ ERROR(attr_ApplicationMain_deprecated,none,
       "%" SELECT_APPLICATION_MAIN "0 is deprecated",
       (unsigned))
 NOTE(attr_ApplicationMain_deprecated_use_attr_main,none,
-     "use @main instead", ())
+     "use '@main' instead", ())
 
 NOTE(attr_ApplicationMain_parse_as_library,none,
      "pass '-parse-as-library' to compiler invocation if this is intentional",
@@ -4191,25 +4298,35 @@ NOTE(attr_ApplicationMain_script_here,none,
      ())
 
 ERROR(attr_MainType_without_main,none,
-      "%0 is annotated with @main and must provide a main static function of type %"
-      SELECT_APPLICATION_MAIN_TYPES "1",
+      "%0 is annotated with '@main' and must provide a main static function "
+      "of type %" SELECT_APPLICATION_MAIN_TYPES "1",
       (const ValueDecl *, bool))
+NOTE(note_add_main_sync,none,
+     "add 'static func main()'", ())
+NOTE(note_add_main_sync_throws,none,
+     "add 'static func main() throws'", ())
+NOTE(note_add_main_async,none,
+     "add 'static func main() async'", ())
+NOTE(note_add_main_async_throws,none,
+     "add 'static func main() async throws'", ())
 
 #undef SELECT_APPLICATION_MAIN_TYPES
 #undef SELECT_APPLICATION_MAIN
 #undef SELECT_APPLICATION_DELEGATE
 
 ERROR(attr_rawlayout_experimental,none,
-      "the @_rawLayout attribute is experimental", ())
+      "the '@_rawLayout' attribute is experimental", ())
 ERROR(attr_rawlayout_cannot_be_copyable,none,
-      "type with @_rawLayout cannot be copied and must be declared ~Copyable", ())
+      "type with '@_rawLayout' cannot be copied and must be declared ~Copyable",
+      ())
 ERROR(attr_rawlayout_cannot_have_stored_properties,none,
-      "type with @_rawLayout cannot have stored properties", ())
+      "type with '@_rawLayout' cannot have stored properties", ())
 ERROR(attr_rawlayout_cannot_have_alignment_attr,none,
-      "type with @_rawLayout cannot also have an @_alignment attribute", ())
+      "type with '@_rawLayout' cannot also have an '@_alignment' attribute", ())
 ERROR(attr_rawlayout_invalid_count_type,none,
-      "@_rawLayout count must either be integer literal or a generic argument", ())
-      
+      "'@_rawLayout' count must either be integer literal or a generic "
+      "argument", ())
+
 // lazy
 ERROR(lazy_not_on_let,none,
       "'lazy' cannot be used on a let", ())
@@ -4233,14 +4350,14 @@ ERROR(lazy_var_storage_access,none,
 
 // Debugger function attribute.
 ERROR(attr_for_debugger_support_only,none,
-      "@LLDBDebuggerSupport may only be used when debugger support is on", ())
+      "'@LLDBDebuggerSupport' may only be used when debugger support is on", ())
 
 // @_implements
 ERROR(implements_attr_protocol_lacks_member,none,
       "protocol %0 has no member %1", (const ProtocolDecl *, DeclName))
 
 ERROR(implements_attr_non_protocol_type,none,
-      "non-protocol type in @_implements attribute", ())
+      "non-protocol type in '@_implements'", ())
 
 ERROR(implements_attr_protocol_not_conformed_to,none,
       "containing type %0 does not conform to protocol %1",
@@ -4331,6 +4448,9 @@ NOTE(derivative_attr_fix_access,none,
      "mark the derivative function as "
      "'%select{private|fileprivate|internal|package|@usableFromInline|@usableFromInline}0' "
      "to match the original function", (AccessLevel))
+ERROR(derivative_attr_always_emit_into_client_mismatch,none,
+      "either both or none of derivative and original function must have "
+      "@alwaysEmitIntoClient attribute", ())
 ERROR(derivative_attr_static_method_mismatch_original,none,
       "unexpected derivative function declaration; "
       "%0 requires the derivative function %1 to be %select{an instance|a 'static'}2 method",
@@ -4373,22 +4493,23 @@ NOTE(transpose_attr_static_method_mismatch_fix,none,
 ERROR(autodiff_attr_original_decl_ambiguous,none,
       "referenced declaration %0 is ambiguous", (DeclNameRef))
 NOTE(autodiff_attr_original_decl_ambiguous_candidate,none,
-     "candidate %0 found here", (DescriptiveDeclKind))
+     "candidate %kindonly0 found here", (const AbstractFunctionDecl *))
 ERROR(autodiff_attr_original_decl_none_valid,none,
       "referenced declaration %0 could not be resolved", (DeclNameRef))
 NOTE(autodiff_attr_original_decl_invalid_kind,none,
-     "candidate %0 is not a 'func', 'init', 'subscript', or 'var' computed "
-     "property declaration", (DescriptiveDeclKind))
+     "candidate %kindonly0 is not a 'func', 'init', 'subscript', or 'var' "
+     "computed property declaration",
+     (const ValueDecl *))
 NOTE(autodiff_attr_original_decl_missing_accessor,none,
-     "candidate %0 does not have a %1",
-     (DescriptiveDeclKind, /*accessorDeclKind*/ DescriptiveDeclKind))
+     "candidate %kindonly0 does not have a %1",
+     (const ValueDecl *, /*accessorDeclKind*/ DescriptiveDeclKind))
 NOTE(autodiff_attr_original_decl_type_mismatch,none,
-     "candidate %0 does not have "
+     "candidate %kindonly0 does not have "
      "%select{expected type|type equal to or less constrained than}2 %1",
-     (DescriptiveDeclKind, Type, /*hasGenericSignature*/ bool))
+     (const ValueDecl *, Type, /*hasGenericSignature*/ bool))
 NOTE(autodiff_attr_original_decl_not_same_type_context,none,
-     "candidate %0 is not defined in the current type context",
-     (DescriptiveDeclKind))
+     "candidate %kindonly0 is not defined in the current type context",
+     (const ValueDecl *))
 ERROR(autodiff_attr_original_void_result,none,
       "cannot differentiate void function %0", (DeclName))
 ERROR(autodiff_attr_result_not_differentiable,none,
@@ -4648,15 +4769,10 @@ ERROR(could_not_infer_pack_element,none,
 NOTE(note_in_opening_pack_element,none,
       "in inferring pack element #%0 of '%1'", (unsigned,StringRef))
 
-      
-ERROR(type_of_expression_is_ambiguous,none,
-      "type of expression is ambiguous without a type annotation", ())
-
-ERROR(failed_to_produce_diagnostic,Fatal,
+ERROR(failed_to_produce_diagnostic,none,
       "failed to produce diagnostic for expression; "
       SWIFT_BUG_REPORT_MESSAGE, ())
 
-
 ERROR(missing_protocol,none,
       "missing protocol %0", (Identifier))
 ERROR(nil_literal_broken_proto,none,
@@ -4754,10 +4870,6 @@ NOTE(descriptive_generic_type_declared_here,none,
 
 ERROR(placeholder_type_not_allowed,none,
       "type placeholder not allowed here", ())
-ERROR(placeholder_type_not_allowed_in_return_type,none,
-      "type placeholder may not appear in function return type", ())
-ERROR(placeholder_type_not_allowed_in_parameter,none,
-      "type placeholder may not appear in top-level parameter", ())
 ERROR(placeholder_type_not_allowed_in_pattern,none,
       "placeholder type may not appear as type of a variable", ())
 NOTE(replace_placeholder_with_inferred_type,none,
@@ -4851,8 +4963,8 @@ NOTE(add_self_to_type,none,
      "use '.self' to reference the type object", ())
 
 WARNING(warn_unqualified_access,none,
-        "use of %0 treated as a reference to %1 in %kind2",
-        (Identifier, DescriptiveDeclKind, const ValueDecl *))
+        "use of %base0 treated as a reference to %kindonly0 in %kind1",
+        (const ValueDecl *, const ValueDecl *))
 WARNING(self_refers_to_method,none,
        "'self' refers to the method '%0.self', which may be unexpected",
        (StringRef))
@@ -4861,22 +4973,22 @@ NOTE(fix_unqualified_access_member,none,
 NOTE(fix_unqualified_access_member_named_self,none,
      "use '%0.self' to silence this warning", (StringRef))
 NOTE(fix_unqualified_access_top_level,none,
-     "use '%0' to reference the %1",
-     (StringRef, DescriptiveDeclKind, Identifier))
+     "use '%0' to reference the %kindonly1",
+     (StringRef, const ValueDecl *, const ModuleDecl *))
 NOTE(fix_unqualified_access_top_level_multi,none,
-     "use '%0' to reference the %1 in module %2",
-     (StringRef, DescriptiveDeclKind, Identifier))
+     "use '%0' to reference the %kindonly1 in module %2",
+     (StringRef, const ValueDecl *, const ModuleDecl *))
 
 WARNING(warn_deprecated_conditional_conformance_outer_access,Deprecation,
-        "use of %0 as reference to %1 in %kind2 will change in future versions "
-        "of Swift to reference %3 in %kind4 which comes via a conditional "
-        "conformance",
+        "use of %0 as reference to %kindonly1 in %kind2 will change in future "
+        "versions of Swift to reference %kindonly3 in %kind4 which comes via "
+        "a conditional conformance",
         (DeclNameRef,
-         /*current*/DescriptiveDeclKind, const ValueDecl *,
-         /*future*/ DescriptiveDeclKind, const ValueDecl *))
+         /*current*/const ValueDecl *, const ValueDecl *,
+         /*future*/const ValueDecl *, const ValueDecl *))
 NOTE(fix_deprecated_conditional_conformance_outer_access,none,
-     "use '%0' to continue to reference the %1",
-     (StringRef, DescriptiveDeclKind))
+     "use '%0' to continue to reference the %kindonly1",
+     (StringRef, const ValueDecl *))
 
 ERROR(unsupported_special_decl_ref, none,
       "referencing %0 as a function value is not implemented", (Identifier))
@@ -4887,7 +4999,7 @@ WARNING(bitcasting_away_noescape, none,
         "'withoutActuallyEscaping' to temporarily escape a function",
         (Type, Type))
 WARNING(bitcasting_to_change_function_rep, none,
-        "'unsafeBitCast' from function type %0 to %1 changes @convention and "
+        "'unsafeBitCast' from function type %0 to %1 changes '@convention' and "
         "is undefined; use an implicit conversion to change conventions",
         (Type, Type))
 WARNING(bitcasting_to_downcast, none,
@@ -4958,6 +5070,8 @@ NOTE(iuo_to_any_coercion_note_func_result,none,
      (const ValueDecl *))
 NOTE(default_optional_to_any,none,
      "provide a default value to avoid this warning", ())
+NOTE(default_optional_parameter,none,
+     "use a default value parameter to avoid this warning", ())
 NOTE(force_optional_to_any,none,
      "force-unwrap the value to avoid this warning", ())
 NOTE(silence_optional_to_any,none,
@@ -4971,43 +5085,48 @@ NOTE(silence_debug_description_in_interpolation_segment_call,none,
      "use 'String(describing:)' to silence this warning", ())
 
 NOTE(noescape_parameter,none,
-    "parameter %1 is implicitly %select{non-escaping|non-sendable}0",
+    "parameter %1 is implicitly %select{non-escaping|non-Sendable}0",
      (unsigned, Identifier))
 NOTE(generic_parameters_always_escaping,none,
      "generic parameters are always considered '@escaping'", ())
 
 ERROR(passing_noattrfunc_to_attrfunc,none,
-      "passing %select{non-escaping|non-sendable}0 parameter %1 to function "
-      "expecting %select{an @escaping|a @Sendable}0 closure",
+      "passing %select{non-escaping|non-Sendable}0 parameter %1 to function "
+      "expecting %select{an '@escaping'|a '@Sendable'}0 closure",
       (unsigned, Identifier))
 ERROR(converting_noescape_param_to_generic_type,none,
       "converting non-escaping parameter %0 to generic parameter %1 may allow it to escape",
       (Identifier, Type))
 ERROR(assigning_noattrfunc_to_attrfunc,none,
-      "assigning %select{non-escaping|non-sendable}0 parameter %1 to "
-      "%select{an @escaping|a @Sendable}0 closure",
+      "assigning %select{non-escaping|non-Sendable}0 parameter %1 to "
+      "%select{an '@escaping'|a '@Sendable'}0 closure",
       (unsigned, Identifier))
 ERROR(general_noattrfunc_to_attr,none,
-      "using %select{non-escaping|non-sendable}0 parameter %1 in a context "
-      "expecting %select{an @escaping|a @Sendable}0 closure",
+      "using %select{non-escaping|non-Sendable}0 parameter %1 in a context "
+      "expecting %select{an '@escaping'|a '@Sendable'}0 closure",
       (unsigned, Identifier))
 ERROR(converting_noattrfunc_to_type,none,
-      "converting %select{non-escaping|non-sendable function}0 value to %1 "
+      "converting %select{non-escaping|non-Sendable function}0 value to %1 "
       "may %select{allow it to escape|introduce data races}0",
       (unsigned, Type))
 NOTE(escape_expected_at_parameter_position,none,
      "parameter #%0 expects escaping value of type %1",
      (unsigned, Type))
 NOTE(add_explicit_escaping,none,
-     "add explicit @escaping to function parameter #%0",
+     "add explicit '@escaping' to function parameter #%0",
      (unsigned))
 
 ERROR(converting_func_loses_global_actor,none,
       "converting function value of type %0 to %1 loses global actor %2",
       (Type, Type, Type))
 ERROR(capture_across_type_decl,none,
-      "%0 declaration cannot close over value %1 defined in outer scope",
-      (DescriptiveDeclKind, Identifier))
+      "%kindonly0 declaration cannot close over value %base1 defined in outer "
+      "scope",
+      (const NominalTypeDecl *, const ValueDecl *))
+
+ERROR(isolated_any_conversion_to_synchronous_func,none,
+      "converting @isolated(any) function of type %0 to synchronous function type %1 is not allowed",
+      (Type, Type))
 
 ERROR(reference_to_invalid_decl,none,
       "cannot reference invalid declaration %0", (const ValueDecl *))
@@ -5106,13 +5225,16 @@ ERROR(assignment_bang_has_immutable_subcomponent,none,
 NOTE(candidate_is_not_assignable,none,
      "candidate is not assignable: %kind0",
      (const ValueDecl *))
+NOTE(candidate_expects_inout_argument,none,
+     "candidate expects in-out value for parameter #%0 but argument is immutable",
+     (unsigned))
 
 NOTE(change_to_mutating,none,
      "mark %select{method|%1}0 'mutating' to make 'self' mutable",
      (bool, StringRef))
 NOTE(masked_mutable_property,none,
-     "add explicit '%0' to refer to mutable %1 of %2",
-     (StringRef, DescriptiveDeclKind, Type))
+     "add explicit '%0' to refer to mutable %kindonly1 of %2",
+     (StringRef, const VarDecl *, Type))
 
 ERROR(assignment_let_property_delegating_init,none,
       "'let' property %0 may not be initialized directly; use "
@@ -5214,14 +5336,16 @@ GROUPED_ERROR(opaque_type_var_no_init,OpaqueTypeInference,none,
 GROUPED_ERROR(opaque_type_var_no_underlying_type,OpaqueTypeInference,none,
       "property declares an opaque return type, but cannot infer the "
       "underlying type from its initializer expression", ())
-
+GROUPED_ERROR(opaque_type_unsupported_availability,OpaqueTypeInference,none,
+      "opaque return type cannot depend on %0 availability",
+      (AvailabilityDomain))
 
 //------------------------------------------------------------------------------
 // MARK: Discard Statement
 //------------------------------------------------------------------------------
 ERROR(discard_wrong_context_decl,none,
-      "'discard' statement cannot appear in %0",
-      (DescriptiveDeclKind))
+      "'discard' statement cannot appear in %kindonly0",
+      (const Decl *))
 ERROR(discard_no_deinit,none,
       "'discard' has no effect for type %0 unless it has a deinitializer",
       (Type))
@@ -5233,10 +5357,10 @@ ERROR(discard_wrong_context_misc,none,
       ())
 ERROR(discard_wrong_context_copyable,none,
       "'discard' statement can only appear in noncopyable type's member",
-      (DescriptiveDeclKind))
+      ())
 ERROR(discard_wrong_context_nonconsuming,none,
-      "'discard' statement can only appear in consuming %0",
-      (DescriptiveDeclKind))
+      "'discard' statement can only appear in consuming %kindonly0",
+      (const FuncDecl *))
 ERROR(discard_wrong_not_self,none,
       "you can only discard 'self'", ())
 ERROR(discard_wrong_module,none,
@@ -5287,8 +5411,8 @@ ERROR(closure_tuple_parameter_destructuring_implicit,none,
       "closure tuple parameter %0 does not support destructuring "
       "with implicit parameters", (Type))
 ERROR(single_tuple_parameter_mismatch_special,none,
-      "%0 expects a single parameter of type %1%2",
-      (DescriptiveDeclKind, Type, StringRef))
+      "%kindonly0 expects a single parameter of type %1%2",
+      (const ValueDecl *, Type, StringRef))
 ERROR(single_tuple_parameter_mismatch_normal,none,
       "%kindbase0 expects a single parameter of type %1%2",
       (const ValueDecl *, Type, StringRef))
@@ -5436,6 +5560,10 @@ WARNING(no_throw_in_do_with_catch,none,
 ERROR(thrown_type_not_error,none,
       "thrown type %0 does not conform to the 'Error' protocol", (Type))
 
+ERROR(typed_throw_in_objc_forbidden,none,
+      "typed 'throws' %kindonly0 cannot be represented in Objective-C",
+      (const AbstractFunctionDecl *))
+
 //------------------------------------------------------------------------------
 // MARK: Concurrency
 //------------------------------------------------------------------------------
@@ -5470,15 +5598,21 @@ FIXIT(insert_globalactor_attr, "@%0 ", (Type))
 ERROR(main_function_must_be_mainActor,none,
       "main() must be '@MainActor'", ())
 
+// Keep aligned with enum ForeignLanguage
+#define FOREIGN_LANG_SELECT "select{C|Objective-C}"
+
 ERROR(not_objc_function_async,none,
-      "'async' %0 cannot be represented in Objective-C", (DescriptiveDeclKind))
+      "'async' %kindonly0 cannot be represented in Objective-C",
+      (const AbstractFunctionDecl *))
 NOTE(not_objc_function_type_async,none,
-      "'async' function types cannot be represented in Objective-C", ())
+     "'async' function types cannot be represented "
+     "in %" FOREIGN_LANG_SELECT "0", (ForeignLanguage))
 ERROR(actor_isolated_objc,none,
-      "actor-isolated %kind0 cannot be @objc",
+      "actor-isolated %kind0 cannot be '@objc'",
        (const ValueDecl *))
 NOTE(protocol_witness_async_conflict,none,
-     "candidate is %select{not |}0'async', but%select{| @objc}1 protocol requirement is%select{| not}0",
+     "candidate is %select{not |}0'async', but%select{| '@objc'}1 protocol "
+     "requirement is%select{| not}0",
      (bool, bool))
 ERROR(async_autoclosure_nonasync_function,none,
       "'async' autoclosure parameter in a non-'async' function", ())
@@ -5560,6 +5694,9 @@ ERROR(actor_isolated_non_self_reference,none,
         "from a nonisolated autoclosure}2",
         (const ValueDecl *, unsigned, unsigned, Type,
          ActorIsolation))
+ERROR(actor_isolated_access_outside_of_actor_context,none,
+      "%0 %kind1 cannot be %select{accessed|called}2 from outside of the actor",
+      (ActorIsolation, const ValueDecl *, bool))
 ERROR(distributed_actor_isolated_non_self_reference,none,
       "distributed actor-isolated %kind0 can not be accessed from a "
       "nonisolated context",
@@ -5571,8 +5708,8 @@ ERROR(conflicting_stored_property_isolation,none,
       "%select{default|memberwise}0 initializer for %1 cannot be both %2 and %3",
       (bool, Type, ActorIsolation, ActorIsolation))
 NOTE(property_requires_actor,none,
-      "initializer for %0 %1 is %2",
-      (DescriptiveDeclKind, Identifier, ActorIsolation))
+      "initializer for %kind0 is %1",
+      (const VarDecl *, ActorIsolation))
 ERROR(isolated_default_argument_context,none,
       "%0 default value in a %1 context", 
       (ActorIsolation, ActorIsolation))
@@ -5607,8 +5744,9 @@ ERROR(actor_isolated_keypath_component,none,
       "cannot form key path to %0 %kind1",
       (ActorIsolation, const ValueDecl *))
 ERROR(effectful_keypath_component,none,
-      "cannot form %select{key path|dynamic key path member lookup}1 to %0 with 'throws' or 'async'",
-      (DescriptiveDeclKind, bool))
+      "cannot form %select{key path|dynamic key path member lookup}1 to "
+      "%kindonly0 with 'throws' or 'async'",
+      (const ValueDecl *, bool))
 ERROR(local_function_executed_concurrently,none,
       "concurrently-executed %kind0 must be marked as '@Sendable'",
       (const ValueDecl *))
@@ -5627,15 +5765,15 @@ GROUPED_ERROR(concurrent_access_of_inout_param,SendableClosureCaptures,none,
       "concurrently-executing code",
       (DeclName))
 GROUPED_ERROR(non_sendable_capture,SendableClosureCaptures,none,
-      "capture of %1 with non-sendable type %0 in a '@Sendable' "
+      "capture of %1 with non-Sendable type %0 in a '@Sendable' "
       "%select{local function|closure}2",
       (Type, DeclName, bool))
 ERROR(non_sendable_isolated_capture,none,
-      "capture of %1 with non-sendable type %0 in an isolated "
+      "capture of %1 with non-Sendable type %0 in an isolated "
       "%select{local function|closure}2",
       (Type, DeclName, bool))
-ERROR(non_sendable_metatype_capture,none,
-      "capture of non-sendable type %0 in an isolated "
+GROUPED_ERROR(non_sendable_metatype_capture,SendableMetatypes,none,
+      "capture of non-Sendable type %0 in an isolated "
       "%select{local function|closure}1",
       (Type, bool))
 ERROR(self_capture_deinit_task,none,
@@ -5667,8 +5805,9 @@ ERROR(distributed_local_cannot_be_used,none,
       "'local' cannot be used in user-defined code currently",
       ())
 ERROR(distributed_actor_func_param_not_codable,none,
-      "parameter '%0' of type %1 in %2 does not conform to serialization requirement '%3'",
-      (StringRef, Type, DescriptiveDeclKind, StringRef))
+      "parameter %0 of type %1 in %kindonly2 does not conform to "
+      "serialization requirement '%3'",
+      (Identifier, Type, const AbstractFunctionDecl *, StringRef))
 ERROR(distributed_actor_target_result_not_codable,none,
       "result type %0 of %kindbase1 does not conform to serialization requirement '%2'",
       (Type, const ValueDecl *, StringRef))
@@ -5696,8 +5835,8 @@ ERROR(conformance_missing_distributed,none,
 NOTE(note_add_distributed_multi,none,
      "mark all declarations used in the conformance 'distributed'", ())
 NOTE(actor_mutable_state,none,
-     "mutation of this %0 is only permitted within the actor",
-     (DescriptiveDeclKind))
+     "mutation of this %kindonly0 is only permitted within the actor",
+     (const ValueDecl *))
 ERROR(shared_mutable_state_access,none,
       "reference to %kind0 is not concurrency-safe because it involves shared "
       "mutable state", (const ValueDecl *))
@@ -5717,7 +5856,7 @@ NOTE(note_actor_isolated_witness,none,
      "%0 %kind1 cannot satisfy %2 requirement",
      (ActorIsolation, const ValueDecl *, ActorIsolation))
 ERROR(actor_cannot_conform_to_global_actor_protocol,none,
-      "actor %0 cannot conform to global actor isolated protocol %1",
+      "actor %0 cannot conform to global-actor-isolated protocol %1",
       (Type, Type))
 NOTE(protocol_isolated_to_global_actor_here,none,
      "%0 is isolated to global actor %1 here", (Type, Type))
@@ -5744,15 +5883,15 @@ ERROR(isolated_parameter_duplicate_type,none,
 NOTE(isolated_parameter_previous_note,none,
      "previous 'isolated' parameter %0", (DeclName))
 ERROR(isolated_parameter_combined_global_actor_attr,none,
-      "%0 with 'isolated' parameter cannot have a global actor",
-      (DescriptiveDeclKind))
+      "%kindonly0 with 'isolated' parameter cannot have a global actor",
+      (const ValueDecl *))
 ERROR(isolated_parameter_closure_combined_global_actor_attr,none,
       "closure with 'isolated' parameter %0 cannot have a global actor", (DeclName))
 ERROR(isolated_parameter_global_actor_type,none,
       "function type cannot have global actor and 'isolated' parameter", ())
 ERROR(isolated_parameter_combined_nonisolated,none,
-      "%0 with 'isolated' parameter cannot be 'nonisolated'",
-      (DescriptiveDeclKind))
+      "%kindonly0 with 'isolated' parameter cannot be 'nonisolated'",
+      (const ValueDecl *))
 ERROR(isolated_parameter_isolated_attr_type,none,
       "function with 'isolated' parameter cannot also be '@isolated(%0)'",
       (StringRef))
@@ -5767,82 +5906,82 @@ NOTE(in_derived_conformance, none,
      "in derived conformance to %0",
      (Type))
 NOTE(in_derived_witness, none,
-     "in %0 %1 for derived conformance to %2",
-     (DescriptiveDeclKind, DeclName, Type))
+     "in %kindonly0 %1 for derived conformance to %2",
+     (const ValueDecl *, DeclName, Type))
 
 ERROR(non_sendable_arg_into_actor,none,
-      "non-sendable type %0 cannot be sent into %2 context in call to %kind1",
+      "non-Sendable type %0 cannot be sent into %2 context in call to %kind1",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_arg_exits_actor,none,
-      "non-sendable type %0 cannot exit %2 context in call to nonisolated "
+      "non-Sendable type %0 cannot exit %2 context in call to nonisolated "
       "%kind1",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_param_in_witness,none,
-      "non-sendable parameter type %0 cannot be sent from caller of "
+      "non-Sendable parameter type %0 cannot be sent from caller of "
       "protocol requirement %1 into %2 implementation",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_param_in_override,none,
-      "non-sendable parameter type %0 cannot be sent from caller of "
+      "non-Sendable parameter type %0 cannot be sent from caller of "
       "superclass %kind1 into %2 override",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_param_in_objc,none,
-      "non-sendable parameter type %0 of %2 '@objc' %kind1 cannot cross actor "
+      "non-Sendable parameter type %0 of %2 '@objc' %kind1 cannot cross actor "
       "boundary",
       (Type, const ValueDecl *, ActorIsolation))
 
 ERROR(non_sendable_result_into_actor,none,
-      "non-sendable result type %0 cannot be sent from %2 context in call "
+      "non-Sendable result type %0 cannot be sent from %2 context in call "
       "to %kind1",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_result_exits_actor,none,
-      "non-sendable result type %0 cannot exit %2 context in call to "
+      "non-Sendable result type %0 cannot exit %2 context in call to "
       "nonisolated %kind1",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_result_in_witness,none,
-      "non-sendable type %0 cannot be returned from %2 implementation "
+      "non-Sendable type %0 cannot be returned from %2 implementation "
       "to caller of protocol requirement %1",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_result_in_override,none,
-      "non-sendable type %0 cannot be returned from %2 override to "
+      "non-Sendable type %0 cannot be returned from %2 override to "
       "caller of superclass %kind1",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_result_in_objc,none,
-      "non-sendable type %0 returned by %2 '@objc' %kind1 cannot cross "
+      "non-Sendable type %0 returned by %2 '@objc' %kind1 cannot cross "
       "actor boundary",
       (Type, const ValueDecl *, ActorIsolation))
 
 ERROR(non_sendable_call_result_type,none,
-      "non-sendable result type %0 cannot be sent from %1 context in call "
+      "non-Sendable result type %0 cannot be sent from %1 context in call "
       "to async function",
       (Type, ActorIsolation))
 
 ERROR(non_sendable_property_exits_actor,none,
-      "non-sendable type %0 of %kind1 cannot exit %2 context",
+      "non-Sendable type %0 of %kind1 cannot exit %2 context",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_property_into_actor,none,
-      "non-sendable type %0 of nonisolated %kind1 cannot be sent to "
+      "non-Sendable type %0 of nonisolated %kind1 cannot be sent to "
       "%2 context",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_property_in_witness,none,
-      "non-sendable type %0 cannot be returned from %2 implementation "
+      "non-Sendable type %0 cannot be returned from %2 implementation "
       "to caller of protocol requirement %1",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_property_in_override,none,
-      "non-sendable type %0 cannot be returned from %2 override to "
+      "non-Sendable type %0 cannot be returned from %2 override to "
       "caller of superclass %kind1",
       (Type, const ValueDecl *, ActorIsolation))
 ERROR(non_sendable_property_in_objc,none,
-      "non-sendable type %0 returned by %2 '@objc' %kind1 cannot cross "
+      "non-Sendable type %0 returned by %2 '@objc' %kind1 cannot cross "
       "actor boundary",
       (Type, const ValueDecl *, ActorIsolation))
 
 ERROR(non_sendable_keypath_capture,none,
-      "cannot form key path that captures non-sendable type %0",
+      "cannot form key path that captures non-Sendable type %0",
       (Type))
 ERROR(non_concurrent_type_member,none,
       "%select{stored property %2|associated value %2}1 of "
-      "'Sendable'-conforming %kind3 has non-sendable type %0",
-      (Type, bool, DeclName, const ValueDecl *))
+      "'Sendable'-conforming %kind3 %select{contains|has}4 non-Sendable type %0",
+      (Type, bool, DeclName, const ValueDecl *, bool))
 ERROR(concurrent_value_class_mutable_property,none,
       "stored property %0 of 'Sendable'-conforming %kind1 is mutable",
       (DeclName, const ValueDecl *))
@@ -5851,30 +5990,38 @@ ERROR(concurrent_value_outside_source_file,none,
       "%kind0; use '@unchecked Sendable' for retroactive conformance",
       (const ValueDecl *))
 ERROR(concurrent_value_nonfinal_class,none,
-      "non-final class %0 cannot conform to 'Sendable'; "
-      "use '@unchecked Sendable'", (DeclName))
+      "non-final class %0 cannot conform to the 'Sendable' protocol", (DeclName))
 ERROR(concurrent_value_inherit,none,
       "'Sendable' class %1 cannot inherit from another class"
       "%select{| other than 'NSObject'}0",
       (bool, DeclName))
 ERROR(non_sendable_type,none,
       "type %0 does not conform to the 'Sendable' protocol", (Type))
+GROUPED_ERROR(non_sendable_metatype_type,SendableMetatypes,none,
+      "type %0 does not conform to the 'SendableMetatype' protocol", (Type))
 ERROR(sendable_raw_storage,none,
-      "struct %0 with @_rawLayout does not conform to the 'Sendable' protocol", (DeclName))
+      "struct %0 with '@_rawLayout' does not conform to the 'Sendable' "
+      "protocol", (DeclName))
 
 ERROR(typeattr_not_inheritance_clause,none,
-      "'%0' attribute only applies in inheritance clauses", (StringRef))
+      "%0 only applies in inheritance clauses",
+      (const TypeAttribute *))
+ERROR(typeattr_not_extension_inheritance_clause,none,
+      "%0 only applies in inheritance clauses in extensions",
+      (const TypeAttribute *))
 ERROR(typeattr_not_existential,none,
-      "'%0' attribute cannot apply to non-protocol type %1", (StringRef, Type))
+      "%0 cannot apply to non-protocol type %1",
+      (const TypeAttribute *, Type))
 
 WARNING(unchecked_conformance_not_special,none,
-      "@unchecked conformance to %0 has no meaning", (Type))
+      "'@unchecked' conformance to %0 has no meaning", (Type))
 WARNING(restate_unchecked_sendable,none,
         "class %0 must restate inherited '@unchecked Sendable' conformance",
         (DeclName))
 
 WARNING(preconcurrency_conformance_not_used,none,
-        "@preconcurrency attribute on conformance to %0 has no effect", (Type))
+        "'@preconcurrency' on conformance to %0 has no effect",
+        (Type))
 
 ERROR(redundant_any_in_existential,none,
        "redundant 'any' in type %0",
@@ -5912,9 +6059,9 @@ WARNING(nonisolated_unsafe_sendable_actor_constant,none,
      "property with 'Sendable' type %0, consider removing it",
      (Type))
 WARNING(nonisolated_unsafe_uneffective_on_funcs,none,
-     "'nonisolated(unsafe)' has no effect on %0 %1, "
+     "'nonisolated(unsafe)' has no effect on %kind0, "
      "consider using 'nonisolated'",
-     (DescriptiveDeclKind, const ValueDecl*))
+     (const ValueDecl *))
 ERROR(nonisolated_non_sendable,none,
       "'nonisolated' can not be applied to variable with non-'Sendable' "
       "type %0",
@@ -5925,16 +6072,11 @@ ERROR(nonisolated_local_var,none,
 ERROR(nonisolated_actor_sync_init,none,
       "'nonisolated' on an actor's synchronous initializer is invalid",
       ())
-ERROR(nonisolated_wrapped_property,none,
-      "'nonisolated' is not supported on properties with property wrappers",
-      ())
-ERROR(nonisolated_lazy,none,
-      "'nonisolated' is not supported on lazy properties",
-      ())
 
 ERROR(non_sendable_from_deinit,none,
-        "cannot access %1 %2 with a non-sendable type %0 from nonisolated deinit",
-        (Type, DescriptiveDeclKind, DeclName))
+        "cannot access %kind1 with a non-Sendable type %0 from nonisolated "
+        "deinit",
+        (Type, const VarDecl *))
 
 ERROR(actor_instance_property_wrapper,none,
       "%0 property in property wrapper type %1 cannot be isolated to "
@@ -5984,7 +6126,7 @@ ERROR(multiple_global_actors,none,
       "declaration can not have multiple global actor attributes (%0 and %1)",
       (Identifier, Identifier))
 ERROR(global_actor_disallowed,none,
-      "%0 cannot have a global actor", (DescriptiveDeclKind))
+      "%kindonly0 cannot have a global actor", (const Decl *))
 ERROR(global_actor_on_actor_class,none,
       "actor %0 cannot have a global actor", (Identifier))
 ERROR(global_actor_on_local_variable,none,
@@ -6015,7 +6157,7 @@ ERROR(actor_isolation_multiple_attr_2,none,
       "%kind0 has multiple actor-isolation attributes (%1 and %2)",
       (const Decl *, DeclAttribute, DeclAttribute))
 ERROR(actor_isolation_multiple_attr_3,none,
-      "%0 %1 has multiple actor-isolation attributes (%2, %3 and %4)",
+      "%0 %1 has multiple actor-isolation attributes (%2, %3, and %4)",
       (const Decl *, DeclAttribute, DeclAttribute, DeclAttribute))
 ERROR(actor_isolation_multiple_attr_4,none,
       "%0 %1 has multiple actor-isolation attributes (%2, %3, %4, and %5)",
@@ -6029,8 +6171,8 @@ ERROR(actor_isolation_superclass_mismatch,none,
       (ActorIsolation, const ClassDecl *, ActorIsolation, const ClassDecl *))
 
 ERROR(async_decl_must_be_available_from_async,none,
-        "asynchronous %0 must be available from asynchronous contexts",
-        (DescriptiveDeclKind))
+        "asynchronous %kindonly0 must be available from asynchronous contexts",
+        (const Decl *))
 ERROR(async_named_decl_must_be_available_from_async,none,
         "asynchronous %kind0 must be available from asynchronous contexts",
         (const ValueDecl *))
@@ -6224,6 +6366,9 @@ ERROR(invalid_ownership_protocol_type,none,
 ERROR(invalid_ownership_incompatible_class,none,
       "%0 is incompatible with %1 references",
       (Type, ReferenceOwnership))
+ERROR(invalid_ownership_incompatible_foreign_reference_type,none,
+      "%0 is incompatible with 'weak' references, because it is a foreign reference type",
+      (Type))
 ERROR(invalid_ownership_with_optional,none,
       "%0 variable cannot have optional type", (ReferenceOwnership))
 ERROR(invalid_ownership_not_optional,none,
@@ -6263,8 +6408,8 @@ NOTE(overridden_required_initializer_here,none,
      "overridden required initializer is here", ())
 
 // Functions
-ERROR(attribute_requires_function_type,none,
-      "@%0 attribute only applies to function types", (StringRef))
+ERROR(type_attr_requires_function_type,none,
+      "%0 only applies to function types", (const TypeAttribute *))
 ERROR(generic_function_type,none,
       "function values cannot be generic", ())
 ERROR(unsupported_convention,none,
@@ -6276,8 +6421,9 @@ ERROR(unreferenced_generic_parameter,NoUsage,
       "generic parameter '%0' is not used in function signature", (StringRef))
 ERROR(unexpected_ctype_for_non_c_convention,none,
       "convention '%0' does not support the 'cType' argument label, did you "
-      "mean @convention(c, cType: \"%1\") or @convention(block, cType: \"%1\") "
-      "instead?", (StringRef, StringRef))
+      "mean '@convention(c, cType: \"%1\")' or "
+      "'@convention(block, cType: \"%1\")' instead?",
+      (StringRef, StringRef))
 ERROR(unable_to_parse_c_function_type,none,
       "unable to parse '%0'; it should be a C function pointer type or a "
       "block pointer type", (StringRef))
@@ -6331,20 +6477,21 @@ ERROR(differentiable_function_type_no_differentiability_parameters,
 
 // SIL
 ERROR(opened_bad_constraint_type,none,
-      "@opened constraint type %0 is not a protocol or protocol composition", (Type))
+      "'@opened' constraint type %0 is not a protocol or protocol composition",
+      (Type))
 ERROR(opened_bad_interface_type,none,
-      "@opened interface type %0 is not a type parameter", (Type))
+      "'@opened' interface type %0 is not a type parameter", (Type))
 ERROR(sil_function_input_label,PointsToFirstBadToken,
       "SIL function types cannot have labeled inputs", ())
 ERROR(sil_non_coro_yields,PointsToFirstBadToken,
-      "non-coroutine SIL function types cannot have @yield results", ())
+      "non-coroutine SIL function types cannot have '@yield' results", ())
 ERROR(sil_function_invalid_convention,PointsToFirstBadToken,
       "convention attribute isn't valid on a %select{parameter|result|callee}0",
       (unsigned))
 ERROR(ast_subst_function_type,none,
       "substitutions cannot be provided on a formal function type", ())
 ERROR(sil_function_multiple_error_results,PointsToFirstBadToken,
-      "SIL function types cannot have multiple @error results", ())
+      "SIL function types cannot have multiple '@error' results", ())
 ERROR(unsupported_sil_convention,none,
       "convention '%0' not supported in SIL", (StringRef))
 ERROR(illegal_sil_type,none,
@@ -6352,17 +6499,19 @@ ERROR(illegal_sil_type,none,
 ERROR(sil_box_arg_mismatch,none,
       "SIL box type has wrong number of generic arguments for layout", ())
 ERROR(sil_pack_element_uuid_not_found,none,
-      "open_pack_element instruction not found for @pack_element type UUID; "
+      "open_pack_element instruction not found for '@pack_element' type UUID; "
       "possible forward reference?", ())
 // SIL Metatypes
 ERROR(sil_metatype_without_repr,none,
-      "metatypes in SIL must have @thin, @thick, or @objc_metatype attribute",
+      "metatypes in SIL must be '@thin', '@thick', or '@objc_metatype'",
       ())
 ERROR(sil_metatype_multiple_reprs,none,
-      "metatypes in SIL can only be one of @thin, @thick, or @objc_metatype",
+      "metatypes in SIL can only be one of '@thin', '@thick', or "
+      "'@objc_metatype'",
       ())
 ERROR(sil_metatype_not_metatype,none,
-      "@thin, @thick, or @objc_metatype can only apply to metatype types in SIL",
+      "'@thin', '@thick', or '@objc_metatype' can only apply to metatype "
+      "types in SIL",
       ())
 
 //------------------------------------------------------------------------------
@@ -6377,14 +6526,14 @@ ERROR(attr_used_without_required_module, none,
       (DeclAttribute, Identifier))
 
 ERROR(invalid_objc_decl_context,none,
-      "@objc can only be used with members of classes, @objc protocols, and "
-      "concrete extensions of classes", ())
+      "'@objc' can only be used with members of classes, '@objc' protocols, "
+      "and concrete extensions of classes", ())
 ERROR(invalid_objc_decl,none,
       "only classes (and their extensions), non-marker protocols, methods, "
       "initializers, properties, and subscript declarations can be declared"
-      " @objc", ())
+      " '@objc'", ())
 ERROR(invalid_objc_swift_rooted_class,none,
-      "only classes that inherit from NSObject can be declared @objc", ())
+      "only classes that inherit from NSObject can be declared '@objc'", ())
 NOTE(invalid_objc_swift_root_class_insert_nsobject,none,
      "inherit from 'NSObject' to silence this error", ())
 
@@ -6400,22 +6549,24 @@ NOTE(objc_header_sorting_arbitrary_please_report,none,
      "declarations", ())
 
 ERROR(invalid_nonobjc_decl,none,
-      "only class members and extensions of classes can be declared @nonobjc", ())
+      "only class members and extensions of classes can be declared "
+      "'@nonobjc'", ())
 ERROR(invalid_nonobjc_extension,none,
-      "only extensions of classes can be declared @nonobjc", ())
+      "only extensions of classes can be declared '@nonobjc'", ())
 
 ERROR(objc_in_extension_context,none,
-      "members of constrained extensions cannot be declared @objc", ())
+      "members of constrained extensions cannot be declared '@objc'", ())
 ERROR(objc_in_generic_extension,none,
       "extensions of %select{classes from generic context|generic classes}0 "
       "cannot contain '@objc' members", (bool))
 ERROR(objc_in_resilient_extension,none,
-      "'@objc' %0 in extension of subclass of %1 requires %2 %3",
-      (DescriptiveDeclKind, Identifier, AvailabilityDomain, AvailabilityRange))
+      "'@objc' %kindonly0 in extension of subclass of %1 requires %2 %3",
+      (const ValueDecl *, const ClassDecl *, AvailabilityDomain,
+       AvailabilityRange))
 ERROR(objc_operator, none,
-      "operator methods cannot be declared @objc", ())
+      "operator methods cannot be declared '@objc'", ())
 ERROR(objc_operator_proto, none,
-      "@objc protocols must not have operator requirements", ())
+      "'@objc' protocols must not have operator requirements", ())
 
 ERROR(objc_for_generic_class,none,
       "generic subclasses of '@objc' classes cannot have an explicit '@objc' "
@@ -6435,7 +6586,7 @@ ERROR(objc_setter_for_nonobjc_subscript,none,
 ERROR(objc_enum_generic,none,
       "'@objc' enum cannot be generic", ())
 ERROR(objc_name_req_nullary,none,
-      "'@objc' %0 must have a simple name", (DescriptiveDeclKind))
+      "'@objc' %kindonly0 must have a simple name", (const Decl *))
 ERROR(objc_name_subscript,none,
       "'@objc' subscript cannot have a name; did you mean to put "
       "the name on the getter or setter?", ())
@@ -6459,15 +6610,15 @@ ERROR(objc_extension_not_class,none,
       "'@objc' can only be applied to an extension of a class", ())
 
 ERROR(objc_name_not_valid_identifier,none,
-      "'@objc' %0 name is not a valid Objective-C identifier",
-      (DescriptiveDeclKind))
+      "'@objc' %kindonly0 name is not a valid Objective-C identifier",
+      (const ValueDecl *))
 ERROR(objc_cannot_infer_name_raw_identifier,none,
-      "cannot infer '@objc' %0 name because the Swift name is not a valid "
-      "Objective-C identifier; specify the name in '@objc' explicitly",
-      (DescriptiveDeclKind))
+      "cannot infer '@objc' %kindonly0 name because the Swift name is not a "
+      "valid Objective-C identifier; specify the name in '@objc' explicitly",
+      (const ValueDecl *))
 
 // If you change this, also change enum ObjCReason
-#define OBJC_ATTR_SELECT "select{marked @_cdecl|marked dynamic|marked @objc|marked @objcMembers|marked @IBOutlet|marked @IBAction|marked @IBSegueAction|marked @NSManaged|a member of an @objc protocol|implicitly @objc|an @objc override|an implementation of an @objc requirement|marked @IBInspectable|marked @GKInspectable|in an @objc extension of a class (without @nonobjc)|in an @objc @implementation extension of a class (without final or @nonobjc)|marked @objc by an access note}"
+#define OBJC_ATTR_SELECT "select{marked '@c'|marked '@_cdecl'|marked dynamic|marked '@objc'|marked '@objcMembers'|marked '@IBOutlet'|marked '@IBAction'|marked '@IBSegueAction'|marked '@NSManaged'|a member of an '@objc' protocol|implicitly '@objc'|an '@objc' override|an implementation of an '@objc' requirement|marked '@IBInspectable'|marked '@GKInspectable'|in an '@objc' extension of a class (without '@nonobjc')|in an '@objc @implementation' extension of a class (without final or '@nonobjc')|marked '@objc' by an access note}"
 
 ERROR(objc_invalid_on_var,none,
       "property cannot be %" OBJC_ATTR_SELECT "0 "
@@ -6476,13 +6627,16 @@ ERROR(objc_invalid_on_subscript,none,
       "subscript cannot be %" OBJC_ATTR_SELECT "0 because its type "
       "cannot be represented in Objective-C", (unsigned))
 ERROR(objc_invalid_on_static_subscript,none,
-      "%0 cannot be %" OBJC_ATTR_SELECT "1", (DescriptiveDeclKind, unsigned))
+      "%kindonly0 cannot be %" OBJC_ATTR_SELECT "1",
+      (const SubscriptDecl *, unsigned))
 ERROR(objc_invalid_with_generic_params,none,
-      "%0 cannot be %" OBJC_ATTR_SELECT "1 because it has generic parameters",
-      (DescriptiveDeclKind, unsigned))
+      "%kindonly0 cannot be %" OBJC_ATTR_SELECT "1 because it has generic "
+      "parameters",
+      (const ValueDecl *, unsigned))
 ERROR(objc_invalid_with_generic_requirements,none,
-      "%0 cannot be %" OBJC_ATTR_SELECT "1 because it has a 'where' clause",
-      (DescriptiveDeclKind, unsigned))
+      "%kindonly0 cannot be %" OBJC_ATTR_SELECT "1 because it has a 'where' "
+      "clause",
+      (const ValueDecl *, unsigned))
 ERROR(objc_convention_invalid,none,
       "%0 is not representable in Objective-C, so it cannot be used"
       " with '@convention(%1)'", (Type, StringRef))
@@ -6500,25 +6654,36 @@ NOTE(not_objc_error_protocol_composition,none,
      "protocol-constrained type containing 'Error' cannot be represented "
      "in Objective-C", ())
 NOTE(not_objc_empty_tuple,none,
-      "empty tuple type cannot be represented in Objective-C", ())
+     "empty tuple type cannot be represented in %" FOREIGN_LANG_SELECT "0",
+     (ForeignLanguage))
 NOTE(not_objc_non_trivial_cxx_class,none,
-     "non-trivial C++ classes cannot be represented in Objective-C", ())
+     "non-trivial C++ classes cannot be represented in "
+     "%" FOREIGN_LANG_SELECT "0",
+     (ForeignLanguage))
 NOTE(not_objc_tuple,none,
-      "tuples cannot be represented in Objective-C", ())
+     "tuples cannot be represented in %" FOREIGN_LANG_SELECT "0",
+     (ForeignLanguage))
 NOTE(not_objc_swift_class,none,
-     "classes not annotated with @objc cannot be represented "
+     "classes not annotated with '@objc' cannot be represented "
      "in Objective-C", ())
 NOTE(not_objc_swift_struct,none,
-      "Swift structs cannot be represented in Objective-C", ())
+      "Swift structs cannot be represented in %" FOREIGN_LANG_SELECT "0",
+     (ForeignLanguage))
 NOTE(not_objc_swift_enum,none,
       "non-'@objc' enums cannot be represented in Objective-C", ())
+NOTE(not_cdecl_or_objc_swift_enum,none,
+     "Swift enums not marked '@c'%select{| or '@objc'}0 cannot be "
+     "represented in %" FOREIGN_LANG_SELECT "0",
+     (ForeignLanguage))
 NOTE(not_objc_generic_type_param,none,
-     "generic type parameters cannot be represented in Objective-C", ())
+     "generic type parameters cannot be represented in "
+     "%" FOREIGN_LANG_SELECT "0", (ForeignLanguage))
 NOTE(not_objc_function_type_param,none,
-     "function types cannot be represented in Objective-C unless their "
-     "parameters and returns can be", ())
+     "function types cannot be represented in %" FOREIGN_LANG_SELECT "0 "
+     "unless their parameters and returns can be", (ForeignLanguage))
 NOTE(not_objc_function_type_throwing,none,
-      "throwing function types cannot be represented in Objective-C", ())
+     "throwing function types cannot be represented in "
+     "%" FOREIGN_LANG_SELECT "0", (ForeignLanguage))
 NOTE(objc_inferring_on_objc_protocol_member,none,
      "inferring '@objc' because the declaration is a member of "
      "an '@objc' protocol", ())
@@ -6528,32 +6693,44 @@ NOTE(objc_witness_objc_requirement,none,
      "satisfying requirement for %kind0 in protocol %1",
      (const ValueDecl *, const ProtocolDecl *))
 
+NOTE(cdecl_incompatible_with_protocols,none,
+     "protocols cannot be represented in C", ())
+NOTE(cdecl_incompatible_with_classes,none,
+     "classes cannot be represented in C", ())
+
 ERROR(no_opaque_return_type_of,none,
       "unable to resolve type for _opaqueReturnTypeOf attribute", ())
 
 ERROR(objc_observing_accessor, none,
-      "observers (%0) are not allowed to be marked '@objc'", (DescriptiveDeclKind))
+      "observers (%kindonly0) are not allowed to be marked '@objc'",
+      (const AccessorDecl *))
 ERROR(objc_init_accessor, none,
-      "init accessors cannot be marked @objc", ())
+      "init accessors cannot be marked '@objc'", ())
 ERROR(objc_addressor, none,
-      "addressors are not allowed to be marked @objc", ())
+      "addressors are not allowed to be marked '@objc'", ())
 ERROR(objc_coroutine_accessor, none,
-      "'read' and 'modify' accessors are not allowed to be marked @objc", ())
+      "'read' and 'modify' accessors are not allowed to be marked '@objc'", ())
+ERROR(objc_borrow_mutate_accessor, none,
+      "borrow and mutate accessors are not allowed to be marked '@objc'", ())
 ERROR(objc_invalid_on_func_variadic,none,
-      "method cannot be %" OBJC_ATTR_SELECT "0 because it has a variadic "
-      "parameter", (unsigned))
+      "%kindonly0 cannot be %" OBJC_ATTR_SELECT "1 because it has a variadic "
+      "parameter", (const AbstractFunctionDecl*, unsigned))
 ERROR(objc_invalid_on_func_inout,none,
-      "method cannot be %" OBJC_ATTR_SELECT "0 because inout "
-      "parameters cannot be represented in Objective-C", (unsigned))
+      "%kindonly0 cannot be %" OBJC_ATTR_SELECT "1 because inout "
+      "parameters cannot be represented in %" FOREIGN_LANG_SELECT "2",
+      (const AbstractFunctionDecl*, unsigned, ForeignLanguage))
 ERROR(objc_invalid_on_func_param_type,none,
-      "method cannot be %" OBJC_ATTR_SELECT "1 because the type of the "
-      "parameter %0 cannot be represented in Objective-C", (unsigned, unsigned))
+      "%kindonly0 cannot be %" OBJC_ATTR_SELECT "2 because the type of the "
+      "parameter %1 cannot be represented in %" FOREIGN_LANG_SELECT "3",
+      (const AbstractFunctionDecl*, unsigned, unsigned, ForeignLanguage))
 ERROR(objc_invalid_on_func_single_param_type,none,
-      "method cannot be %" OBJC_ATTR_SELECT "0 because the type of the "
-      "parameter cannot be represented in Objective-C", (unsigned))
+      "%kindonly0 cannot be %" OBJC_ATTR_SELECT "1 because the type of the "
+      "parameter cannot be represented in %" FOREIGN_LANG_SELECT "2",
+      (const AbstractFunctionDecl*, unsigned, ForeignLanguage))
 ERROR(objc_invalid_on_func_result_type,none,
-      "method cannot be %" OBJC_ATTR_SELECT "0 because its result type "
-      "cannot be represented in Objective-C", (unsigned))
+      "%kindonly0 cannot be %" OBJC_ATTR_SELECT "1 because its result type "
+      "cannot be represented in %" FOREIGN_LANG_SELECT "2",
+      (const AbstractFunctionDecl*, unsigned, ForeignLanguage))
 ERROR(objc_invalid_on_foreign_class,none,
       "method cannot be %" OBJC_ATTR_SELECT "0 because Core Foundation "
       "types are not classes in Objective-C", (unsigned))
@@ -6573,9 +6750,9 @@ ERROR(objc_invalid_on_failing_init,none,
       (unsigned))
 
 ERROR(objc_in_objc_runtime_visible,none,
-      "%0 cannot be %" OBJC_ATTR_SELECT "1 because class %2 is only visible "
-      "via the Objective-C runtime",
-      (DescriptiveDeclKind, unsigned, Identifier))
+      "%kindonly0 cannot be %" OBJC_ATTR_SELECT "1 because class %2 is only "
+      "visible via the Objective-C runtime",
+      (const ValueDecl *, unsigned, const ClassDecl *))
 
 ERROR(objc_override_method_selector_mismatch,none,
       "Objective-C method has a different selector from the "
@@ -6673,36 +6850,39 @@ WARNING(witness_non_objc_storage_optional,none,
       (bool, DeclName, Identifier))
 
 ERROR(nonobjc_not_allowed,none,
-      "declaration is %" OBJC_ATTR_SELECT "0, and cannot be marked @nonobjc",
+      "declaration is %" OBJC_ATTR_SELECT "0, and cannot be marked '@nonobjc'",
       (unsigned))
 
 #undef OBJC_DIAG_SELECT_2
 #undef OBJC_DIAG_SELECT
 #undef OBJC_ATTR_SELECT
+#undef FOREIGN_LANG_SELECT
 
 //------------------------------------------------------------------------------
 // MARK: @exclusivity
 //------------------------------------------------------------------------------
 ERROR(exclusivity_on_wrong_decl,none,
-      "@exclusivity can only be used on class properties, static properties and global variables",
+      "'@exclusivity' can only be used on class properties, static properties "
+      "and global variables",
       ())
 
 ERROR(exclusivity_on_computed_property,none,
-      "@exclusivity can only be used on stored properties",
+      "'@exclusivity' can only be used on stored properties",
       ())
 
 //------------------------------------------------------------------------------
 // MARK: @_borrowed
 //------------------------------------------------------------------------------
 ERROR(borrowed_with_objc_dynamic,none,
-      "%0 cannot be '@_borrowed' if it is '@objc dynamic'",
-      (DescriptiveDeclKind))
+      "%kindonly0 cannot be '@_borrowed' if it is '@objc dynamic'",
+      (const AbstractStorageDecl *))
 ERROR(borrowed_on_objc_protocol_requirement,none,
-      "%0 cannot be '@_borrowed' if it is an @objc protocol requirement",
-      (DescriptiveDeclKind))
+      "%kindonly0 cannot be '@_borrowed' if it is an '@objc' protocol "
+      "requirement",
+      (const AbstractStorageDecl *))
 ERROR(borrowed_with_effect,none,
-      "%0 cannot be '@_borrowed' if it is 'async' or 'throws'",
-      (DescriptiveDeclKind))
+      "%kindonly0 cannot be '@_borrowed' if it is 'async' or 'throws'",
+      (const AccessorDecl *))
 
 //------------------------------------------------------------------------------
 // MARK: dynamic
@@ -6741,9 +6921,9 @@ ERROR(dynamic_replacement_not_in_extension, none,
 ERROR(dynamic_replacement_must_not_be_dynamic, none,
       "dynamicReplacement(for:) of %0 must not be dynamic itself", (DeclName))
 ERROR(dynamic_replacement_replaced_not_objc_dynamic, none,
-      "%0 is not marked @objc dynamic", (DeclName))
+      "%0 is not marked '@objc dynamic'", (DeclName))
 ERROR(dynamic_replacement_replacement_not_objc_dynamic, none,
-      "%0 is marked @objc dynamic", (DeclName))
+      "%0 is marked '@objc dynamic'", (DeclName))
 ERROR(dynamic_replacement_replaced_constructor_is_convenience, none,
       "replaced initializer %0 is marked as convenience", (DeclNameRef))
 ERROR(dynamic_replacement_replaced_constructor_is_not_convenience, none,
@@ -6794,14 +6974,24 @@ ERROR(availability_must_occur_alone, none,
       (AvailabilityDomain, bool))
 ERROR(availability_unexpected_version, none,
       "unexpected version number for %0", (AvailabilityDomain))
-WARNING(availability_unrecognized_platform_name,
-        PointsToFirstBadToken, "unrecognized platform name %0", (Identifier))
-WARNING(availability_suggest_platform_name,
-        PointsToFirstBadToken, "unrecognized platform name %0;"
-        " did you mean '%1'?",
+GROUPED_ERROR(availability_unrecognized_platform_name,
+        AvailabilityUnrecognizedName, PointsToFirstBadToken,
+        "unrecognized platform name %0", (Identifier))
+GROUPED_ERROR(availability_suggest_platform_name,
+        AvailabilityUnrecognizedName, PointsToFirstBadToken,
+        "unrecognized platform name %0; did you mean '%1'?",
         (Identifier, StringRef))
 WARNING(availability_unsupported_version_number, none,
         "'%0' is not a supported version number", (llvm::VersionTuple))
+WARNING(availability_invalid_version_number_for_domain, none,
+        "'%0' is not a valid version number for %1",
+        (llvm::VersionTuple, AvailabilityDomain))
+WARNING(availability_domain_renamed, none,
+        "%0 has been renamed to '%1'",
+        (Identifier, StringRef))
+ERROR(availability_domain_requires_feature, none,
+      "%0 requires '-enable-experimental-feature %1'",
+      (AvailabilityDomain, StringRef))
 
 WARNING(attr_availability_expected_deprecated_version, none,
        "expected version number with 'deprecated' in '%0' attribute for %1",
@@ -6812,9 +7002,26 @@ WARNING(attr_availability_cannot_be_used_for_domain, none,
 WARNING(attr_availability_expected_version_spec, none,
        "expected 'introduced', 'deprecated', or 'obsoleted' in '%0' attribute "
        "for %1", (const DeclAttribute, AvailabilityDomain))
-ERROR(attr_availability_requires_custom_availability, none,
-      "%0 requires '-enable-experimental-feature CustomAvailability'",
-      (AvailabilityDomain))
+ERROR(attr_availability_domain_access, none,
+      "availability domain '%0' is "
+      "%select{private|fileprivate|internal|package|%error|%error}1 "
+      "and cannot be used in '%2' on "
+      "%select{private|fileprivate|internal|package|public|%error}3 %kind4",
+      (AvailabilityDomain, AccessLevel, DeclAttribute, AccessLevel,
+       const Decl *))
+ERROR(attr_availability_domain_not_usable_from_inline, none,
+      "availability domain '%0' used in '%1' on %kind2 must be "
+      "'@usableFromInline' or public",
+      (AvailabilityDomain, DeclAttribute, const Decl *))
+
+GROUPED_WARNING(attr_availability_has_no_effect_domain_always_available,
+                AlwaysAvailableDomain, none,
+                "'%0' has no effect because '%1' is always available",
+                (DeclAttribute, AvailabilityDomain))
+GROUPED_WARNING(attr_availability_domain_always_available,
+                AlwaysAvailableDomain, none,
+                "'%0' is always available, use '*' instead",
+                (AvailabilityDomain))
 
 ERROR(availability_decl_unavailable, none,
       "%0 is unavailable%select{ in %2|}1%select{|: %3}3",
@@ -6858,12 +7065,12 @@ NOTE(note_deprecated_rename, none,
      "use '%0' instead", (StringRef))
 
 ERROR(availability_decl_more_than_enclosing, none,
-      "%0 cannot be more available than enclosing scope",
-      (DescriptiveDeclKind))
+      "%kindonly0 cannot be more available than enclosing scope",
+      (const Decl *))
 
 NOTE(availability_implicit_decl_here, none,
-     "%0 implicitly declared here with availability of %1 %2 or newer",
-     (DescriptiveDeclKind, AvailabilityDomain, AvailabilityRange))
+     "%kindonly0 implicitly declared here with availability of %1 %2 or newer",
+     (const Decl *, AvailabilityDomain, AvailabilityRange))
 
 NOTE(availability_decl_more_than_enclosing_here, none,
      "enclosing scope requires availability of %0 %1 or newer",
@@ -6893,8 +7100,8 @@ ERROR(availability_parameterized_protocol_only_version_newer, none,
       (AvailabilityDomain, AvailabilityRange))
 
 ERROR(availability_isolated_any_only_version_newer, none,
-      "runtime support for @isolated(any) function types is only available in "
-      "%0 %1 or newer",
+      "runtime support for '@isolated(any)' function types is only available "
+      "in %0 %1 or newer",
       (AvailabilityDomain, AvailabilityRange))
 
 ERROR(availability_copyable_generics_casting_only_version_newer, none,
@@ -6920,10 +7127,7 @@ NOTE(availability_guard_with_version_check, none,
      "add 'if #available' version check", ())
 
 NOTE(availability_add_attribute, none,
-     "add @available attribute to enclosing %0", (DescriptiveDeclKind))
-FIXIT(insert_available_attr,
-      "@available(%0 %1, *)\n%2",
-      (StringRef, StringRef, StringRef))
+     "add '@available' attribute to enclosing %kindonly0", (const Decl *))
 
 ERROR(availability_inout_accessor_only_in, none,
       "cannot pass as inout because %0 is only available in %1"
@@ -6940,6 +7144,12 @@ WARNING(availability_query_useless_enclosing_scope, none,
 NOTE(availability_query_useless_enclosing_scope_here, none,
      "enclosing scope here", ())
 
+GROUPED_WARNING(availability_query_useless_always_true,
+                AlwaysAvailableDomain, none,
+                "unnecessary check for '%0'; "
+                "this condition will always be %select{false|true}1",
+                (AvailabilityDomain, unsigned))
+
 ERROR(availability_decl_no_potential, none,
       "%kindonly0 cannot be marked potentially unavailable with '@available'",
       (const Decl *))
@@ -6977,6 +7187,11 @@ ERROR(availability_protocol_requires_version,
       (const ProtocolDecl *, const ValueDecl *, AvailabilityDomain,
        AvailabilityRange))
 
+ERROR(availability_protocol_requirement_only_available_in,
+      none, "protocol %0 requirement %1 cannot be satisfied by %kindonly1 that "
+      "is only available in %2",
+      (const ProtocolDecl *, const ValueDecl *, AvailabilityDomain))
+
 NOTE(availability_protocol_requirement_here, none,
      "protocol requirement here", ())
 
@@ -7056,7 +7271,8 @@ ERROR(unavailability_query_wildcard_not_required, none,
 //------------------------------------------------------------------------------
 
 WARNING(discardable_result_on_void_never_function, none,
-        "@discardableResult declared on a function returning %select{Never|Void}0 "
+        "'@discardableResult' declared on a function returning "
+        "'%select{Never|Void}0' "
         "is unnecessary", (bool))
 
 //------------------------------------------------------------------------------
@@ -7120,6 +7336,7 @@ ERROR(inlinable_decl_ref_from_hidden_module,
       "%2 was imported for SPI only|"
       "%2 was not imported by this file|"
       "C++ APIs from imported module %2 do not support library evolution|"
+      "it was imported via the internal bridging header|"
       "%2 was not imported publicly}3",
       (const ValueDecl *, unsigned, Identifier, unsigned))
 
@@ -7131,6 +7348,7 @@ ERROR(inlinable_typealias_desugars_to_type_from_hidden_module,
       "%4 was imported for SPI only|"
       "%4 was not imported by this file|"
       "C++ types from imported module %4 do not support library evolution|"
+      "it was imported via the internal bridging header|"
       "%4 was not imported publicly}5",
       (const TypeAliasDecl *, StringRef, StringRef, unsigned, Identifier, unsigned))
 
@@ -7176,23 +7394,25 @@ ERROR(resilient_associated_type_less_available_requires_default,none,
 //------------------------------------------------------------------------------
 
 ERROR(specialize_attr_nongeneric_trailing_where,none,
-      "trailing 'where' clause in '_specialize' attribute of non-generic function %0", (DeclName))
+      "trailing 'where' clause in %select{'_specialize'|'specialized'}1 attribute of non-generic function %0", (DeclName, bool))
 ERROR(specialize_missing_where_clause,none,
-      "missing 'where' clause in '_specialize' attribute", ())
+      "missing 'where' clause in %select{'_specialize'|'specialized'}0 attribute", (bool))
 ERROR(specialize_empty_where_clause,none,
-      "empty 'where' clause in '_specialize' attribute", ())
+      "empty 'where' clause in %select{'_specialize'|'specialized'}0 attribute", (bool))
 ERROR(specialize_attr_non_concrete_same_type_req,none,
-      "only concrete type same-type requirements are supported by '_specialize' attribute", ())
+      "only concrete type same-type requirements are supported by %select{'_specialize'|'specialized'}0 attribute", (bool))
 ERROR(specialize_attr_only_generic_param_req,none,
-      "only requirements on generic parameters are supported by '_specialize' attribute", ())
+      "only requirements on generic parameters are supported by %select{'_specialize'|'specialized'}0 attribute", (bool))
 ERROR(specialize_attr_type_parameter_count_mismatch,none,
       "too few generic parameters are specified "
-      "in '_specialize' attribute (got %0, but expected %1)",
-      (unsigned, unsigned))
+      "in %select{'_specialize'|'specialized'}2 attribute (got %0, but expected %1)",
+      (unsigned, unsigned, bool))
 NOTE(specialize_attr_missing_constraint,none,
-      "missing constraint for %0 in '_specialize' attribute", (DeclName))
+      "missing constraint for %0 in %select{'_specialize'|'specialized'}1 attribute", (DeclName, bool))
 ERROR(specialize_attr_unsupported_kind_of_req,none,
       "only same-type and layout requirements are supported by '_specialize' attribute", ())
+ERROR(specialized_attr_unsupported_kind_of_req,none,
+      "only same-type are supported by 'specialized' attribute", ())
 ERROR(specialize_target_function_not_found, none,
      "target function %0 could not be found", (DeclNameRef))
 ERROR(specialize_target_function_of_type_not_found, none,
@@ -7239,6 +7459,14 @@ WARNING(variable_tuple_elt_never_mutated, none,
         "variable %0 was never mutated; "
         "consider changing the pattern to 'case (..., let %1, ...)'",
         (Identifier, StringRef))
+GROUPED_WARNING(weak_variable_never_mutated, WeakMutability, none,
+                "weak variable %0 was never mutated; "
+                "consider %select{removing 'var' to make it|changing to 'let'}1 constant",
+                (Identifier, bool))
+GROUPED_WARNING(weak_variable_tuple_elt_never_mutated, WeakMutability, none,
+                "weak variable %0 was never mutated; "
+                "consider changing the pattern to 'case (..., let %1, ...)'",
+                (Identifier, StringRef))
 WARNING(variable_never_read, none,
         "variable %0 was written to, but never read",
         (Identifier))
@@ -7344,7 +7572,7 @@ GROUPED_ERROR(property_wrapper_ambiguous_value_property,PropertyWrappers,none,
   "named %1", (Type, Identifier))
 GROUPED_ERROR(property_wrapper_wrong_initial_value_init,PropertyWrappers,none,
       "%0 parameter type (%1) must be the same as its "
-      "'wrappedValue' property type (%2) or an @autoclosure thereof",
+      "'wrappedValue' property type (%2) or an '@autoclosure' thereof",
       (DeclName, Type, Type))
 GROUPED_ERROR(property_wrapper_failable_init,PropertyWrappers,none,
       "property wrapper initializer %0 cannot be failable", (DeclName))
@@ -7369,8 +7597,8 @@ ERROR(property_wrapper_attribute_not_on_property, none,
       "property wrapper attribute %0 can only be applied to a property",
       (Identifier))
 ERROR(property_wrapper_param_not_supported,none,
-      "property wrapper attribute on parameter not yet supported on %0",
-      (DescriptiveDeclKind))
+      "property wrapper attribute on parameter not yet supported on %kindonly0",
+      (const ValueDecl *))
 NOTE(property_wrapper_declared_here,none,
      "property wrapper type %0 declared here", (Identifier))
 ERROR(invalid_projection_argument,none,
@@ -7403,12 +7631,13 @@ ERROR(property_wrapper_computed, none,
       "property wrapper cannot be applied to a computed property",
       ())
 ERROR(property_wrapper_effectful,none,
-      "property wrapper's 'wrappedValue' property cannot define an 'async' or 'throws' %0",
-    (DescriptiveDeclKind))
+      "property wrapper's 'wrappedValue' property cannot define an 'async' or "
+      "'throws' %kindonly0",
+      (const AccessorDecl *))
 
 ERROR(property_with_wrapper_conflict_attribute,none,
       "property %0 with a wrapper cannot also be "
-      "%select{lazy|@NSCopying|@NSManaged|weak|unowned|unmanaged}1",
+      "%select{lazy|'@NSCopying'|'@NSManaged'|'@abi'|weak|unowned|unmanaged}1",
       (Identifier, int))
 ERROR(property_wrapper_not_single_var, none,
       "property wrapper can only apply to a single variable", ())
@@ -7611,8 +7840,8 @@ ERROR(marker_protocol_conditional_conformance,none,
 //------------------------------------------------------------------------------
 
 ERROR(differentiable_programming_attr_used_without_required_module, none,
-      "'@%0' attribute used without importing module %1",
-      (StringRef, Identifier))
+      "%0 used without importing module %1",
+      (const TypeAttribute *, Identifier))
 
 //------------------------------------------------------------------------------
 // MARK: OSLog
@@ -7647,24 +7876,28 @@ ERROR(atomics_ordering_must_be_constant, none,
 
 #define WHICH_ACCESS_NOTE(reason) "specified by access note for %" #reason
 
+WARNING(access_notes_file_io_error,none,
+        "ignored access notes file at '%0' because it cannot be read: %1",
+        (StringRef, StringRef))
+
 REMARK(attr_added_by_access_note, none,
-       "implicitly added '%1' to this %2, as " WHICH_ACCESS_NOTE(0),
-       (StringRef, StringRef, DescriptiveDeclKind))
+       "implicitly added '%1' to this %kindonly2, as " WHICH_ACCESS_NOTE(0),
+       (StringRef, StringRef, const ValueDecl *))
 NOTE(fixit_attr_added_by_access_note, none,
      "add '%0' explicitly to silence this warning",
      (StringRef))
 
 REMARK(attr_removed_by_access_note, none,
-       "implicitly removed '%1' from this %3, as " WHICH_ACCESS_NOTE(0),
-       (StringRef, StringRef, DescriptiveDeclKind))
+       "implicitly removed '%1' from this %kindonly2, as " WHICH_ACCESS_NOTE(0),
+       (StringRef, StringRef, const ValueDecl *))
 NOTE(fixit_attr_removed_by_access_note, none,
      "remove '%0' explicitly to silence this warning",
      (StringRef))
 
 REMARK(attr_objc_name_changed_by_access_note, none,
-       "implicitly changed Objective-C name of this %1 to %2, as "
+       "implicitly changed Objective-C name of this %kindonly1 to %2, as "
        WHICH_ACCESS_NOTE(0),
-       (StringRef, DescriptiveDeclKind, ObjCSelector))
+       (StringRef, const ValueDecl *, ObjCSelector))
 NOTE(fixit_attr_objc_name_changed_by_access_note, none,
      "change Objective-C name explicitly to silence this warning",
      ())
@@ -7673,13 +7906,13 @@ NOTE(fixit_attr_objc_name_changed_by_access_note, none,
 // '-Raccess-note=all-validate' emits them as errors.
 
 ERROR(attr_objc_name_conflicts_with_access_note, none,
-      "ignored access note: did not change Objective-C name of this %1 from %2 "
-      "to %3, even though it was " WHICH_ACCESS_NOTE(0),
-      (StringRef, DescriptiveDeclKind, ObjCSelector, ObjCSelector))
+      "ignored access note: did not change Objective-C name of this "
+      "%kindonly1 from %2 to %3, even though it was " WHICH_ACCESS_NOTE(0),
+      (StringRef, const ValueDecl *, ObjCSelector, ObjCSelector))
 ERROR(wrap_invalid_attr_added_by_access_note, none,
-      "ignored access note: %0; did not implicitly add '%2' to this %3, even "
-      "though it was " WHICH_ACCESS_NOTE(1),
-      (DiagnosticInfo *, StringRef, StringRef, DescriptiveDeclKind))
+      "ignored access note: %0; did not implicitly add '%2' to this "
+      "%kindonly3, even though it was " WHICH_ACCESS_NOTE(1),
+      (DiagnosticInfo *, StringRef, StringRef, const ValueDecl *))
 
 #undef WHICH_ACCESS_NOTE
 
@@ -7756,11 +7989,6 @@ ERROR(has_symbol_invalid_decl,none,
 ERROR(no_metadata_on_non_generic_param, none,
 "'@_noMetadata' must appear on a generic parameter",
 ())
-ERROR(experimental_no_metadata_feature_can_only_be_used_when_enabled,
-      none, "Can not use feature when experimental layout based"
-      " pre-specializations are disabled! Pass the frontend flag"
-      " -enable-experimental-feature LayoutPrespecialization to swift to enable "
-      " the usage of this language feature", ())
 
 
 //------------------------------------------------------------------------------
@@ -7772,7 +8000,7 @@ ERROR(expected_macro_expansion_expr,PointsToFirstBadToken,
 ERROR(expected_macro_expansion_decls,PointsToFirstBadToken,
       "expected macro expansion to produce a declaration", ())
 ERROR(macro_undefined,PointsToFirstBadToken,
-      "no macro named %0", (Identifier))
+      "no macro named %0", (DeclName))
 ERROR(external_macro_not_found,none,
       "external macro implementation type '%0.%1' could not be found for "
       "macro %2; %3", (StringRef, StringRef, DeclName, StringRef))
@@ -7798,8 +8026,9 @@ WARNING(macro_type_access_warn,none,
 ERROR(macro_in_nested,none,
       "macro %0 can only be declared at file scope", (DeclName))
 ERROR(macro_without_role,none,
-      "macro %0 must declare its applicable roles via '@freestanding' or @attached'",
-       (DeclName))
+      "macro %0 must declare its applicable roles via '@freestanding' or "
+      "'@attached'",
+      (DeclName))
 ERROR(macro_result_type_cannot_be_used,none,
       "only a freestanding expression macro can produce a result of type %0",
       (Type))
@@ -7820,8 +8049,8 @@ ERROR(external_macro_arg_not_type_name,none,
       "argument to `#externalMacro` must be a string literal naming "
       "the external macro's %select{module|type}0", (unsigned))
 ERROR(invalid_decl_in_macro_expansion,none,
-      "macro expansion cannot introduce %0",
-      (DescriptiveDeclKind))
+      "macro expansion cannot introduce %kindonly0",
+      (const Decl *))
 ERROR(let_accessor_expansion,none,
       "cannot expand accessor macro on variable declared with 'let'",
       ())
@@ -7847,8 +8076,8 @@ ERROR(macro_nonobserving_accessor_missing_from_expansion,none,
       "(such as 'get') as expected",
       (DeclName))
 ERROR(macro_nonobserver_unexpected_in_expansion,none,
-      "expansion of macro %0 produced an unexpected %1",
-      (DeclName, DescriptiveDeclKind))
+      "expansion of %kind0 produced an unexpected %kindonly1",
+      (const MacroDecl *, const AccessorDecl *))
 ERROR(macro_init_accessor_not_documented,none,
       "expansion of macro %0 produced an unexpected 'init' accessor",
       (DeclName))
@@ -7863,8 +8092,8 @@ ERROR(extension_macro_invalid_conformance,none,
       "invalid protocol conformance %0 in extension macro",
       (Type))
 ERROR(macro_attached_to_invalid_decl,none,
-      "'%0' macro cannot be attached to %1 (%base2)",
-      (StringRef, DescriptiveDeclKind, const Decl *))
+      "'%0' macro cannot be attached to %kindonly1 (%base1)",
+      (StringRef, const Decl *))
 ERROR(conformance_macro,none,
       "conformance macros are replaced by extension macros",
       ())
@@ -7957,7 +8186,7 @@ NOTE(note_non_bitwise_copyable_type_indirect_enum_element,none,
 ERROR(non_bitwise_copyable_type_suppressed,none,
       "cannot both conform to and suppress conformance to 'BitwiseCopyable'", ())
 ERROR(non_bitwise_copyable_type_sensitive,none,
-      "a @sensitive type cannot conform to 'BitwiseCopyable'", ())
+      "a '@sensitive' type cannot conform to 'BitwiseCopyable'", ())
 ERROR(non_bitwise_copyable_type_cxx_nontrivial,none,
       "non-trivial C++ type cannot conform to 'BitwiseCopyable'", ())
 ERROR(non_bitwise_copyable_c_type_nontrivial,none,
@@ -8025,7 +8254,8 @@ NOTE(noncopyable_generics_implicit_composition, none,
      "'%noformat0 & %noformat1' is implicit here",
      (Type, Type))
 ERROR(noncopyable_effectful_getter,none,
-      "%0 of noncopyable type cannot be 'async' or 'throws'", (DescriptiveDeclKind))
+      "%kindonly0 of noncopyable type cannot be 'async' or 'throws'",
+      (const AccessorDecl *))
 ERROR(noncopyable_enums_do_not_support_indirect,none,
       "noncopyable enum %0 cannot be marked indirect or have indirect cases yet", (Identifier))
 ERROR(noncopyable_cast,none,
@@ -8071,8 +8301,8 @@ ERROR(noimplicitcopy_attr_valid_only_on_local_let_params,
 ERROR(noimplicitcopy_attr_not_allowed_on_moveonlytype,none,
       "'@_noImplicitCopy' has no effect when applied to a noncopyable type", ())
 ERROR(noncopyable_types_cannot_be_resilient, none,
-      "noncopyable %kind0 must be @frozen in library evolution mode; "
-      "non-@frozen public and @usableFromInline noncopyable types are not "
+      "noncopyable %kind0 must be '@frozen' in library evolution mode; "
+      "non-'@frozen' public and '@usableFromInline' noncopyable types are not "
       "supported",
       (const ValueDecl *))
 ERROR(noncopyable_cannot_have_read_set_accessor,none,
@@ -8084,12 +8314,12 @@ ERROR(noncopyable_cannot_have_read_set_accessor,none,
 //------------------------------------------------------------------------------
 
 ERROR(init_accessor_can_refer_only_to_properties,none,
-      "init accessor cannot refer to %0 %1; init accessors can refer only"
+      "init accessor cannot refer to %kind0; init accessors can refer only"
       " to stored properties",
-      (DescriptiveDeclKind, DeclNameRef))
+      (const ValueDecl *))
 
 ERROR(storage_restrictions_attribute_not_on_init_accessor,none,
-      "@storageRestrictions attribute could only be used with init accessors",
+      "'@storageRestrictions' could only be used with init accessors",
       ())
 ERROR(init_accessor_property_both_init_and_accessed,none,
       "property %0 cannot be both initialized and accessed",
@@ -8132,6 +8362,9 @@ ERROR(pack_iteration_where_clause_not_supported, none,
 // MARK: Lifetime Dependence Syntax
 //------------------------------------------------------------------------------
 
+WARNING(use_lifetime_underscored, PointsToFirstBadToken,
+      "Unsupported use of @lifetime, use @_lifetime to specify lifetime dependencies", ())
+
 ERROR(lifetime_dependence_invalid_param_name, none,
       "invalid parameter name specified %0", (Identifier))
 ERROR(lifetime_dependence_invalid_param_index, none,
@@ -8166,42 +8399,48 @@ ERROR(lifetime_dependence_immortal_alone, none,
       "cannot specify any other dependence source along with immortal", ())
 ERROR(lifetime_dependence_invalid_inherit_escapable_type, none,
       "cannot copy the lifetime of an Escapable type, use "
-      "'@lifetime(borrow %0)' instead",
+      "'@_lifetime(%0%1)' instead",
+      (StringRef, StringRef))
+ERROR(lifetime_dependence_parsed_borrow_with_ownership, none,
+      "invalid use of %0 dependence with %1 ownership",
+      (StringRef, StringRef))
+NOTE(lifetime_dependence_parsed_borrow_with_ownership_fix, none,
+     "use '@_lifetime(%0%1)' instead",
+     (StringRef, StringRef))
+ERROR(lifetime_dependence_cannot_use_default_escapable_consuming, none,
+      "invalid lifetime dependence on an Escapable value with %0 ownership",
       (StringRef))
-ERROR(lifetime_dependence_cannot_use_parsed_borrow_consuming, none,
-      "invalid use of borrow dependence with consuming ownership",
-      ())
 ERROR(lifetime_dependence_cannot_use_parsed_borrow_inout, none,
-      "invalid use of borrow dependence on the same inout parameter",
+      "invalid use of inout dependence on the same inout parameter",
       ())
 ERROR(lifetime_dependence_duplicate_target, none,
       "invalid duplicate target lifetime dependencies on function", ())
 ERROR(lifetime_parameter_requires_inout, none,
-      "lifetime-dependent parameter must be 'inout'", (Identifier))
+      "lifetime-dependent parameter '%0' must be 'inout'", (StringRef))
+ERROR(lifetime_target_requires_nonescapable, none,
+      "invalid lifetime dependence on an Escapable %0", (StringRef))
 
 //------------------------------------------------------------------------------
 // MARK: Lifetime Dependence Requirements
 //------------------------------------------------------------------------------
 
 ERROR(lifetime_dependence_feature_required_return, none,
-      "%0 with a ~Escapable result requires "
-      "'-enable-experimental-feature LifetimeDependence'", (StringRef))
+      "%0 cannot return a ~Escapable result", (StringRef))
 ERROR(lifetime_dependence_feature_required_mutating, none,
-      "%0 with ~Escapable 'self' requires "
-      "'-enable-experimental-feature LifetimeDependence'", (StringRef))
+      "%0 cannot have a ~Escapable 'self'", (StringRef))
 ERROR(lifetime_dependence_feature_required_inout, none,
-      "%0 with a ~Escapable 'inout' parameter requires "
-      "'-enable-experimental-feature LifetimeDependence'",
-      // arg list is interchangable with lifetime_dependence_cannot_infer_inout
-      (StringRef, Identifier))
+      "%0 cannot have a ~Escapable 'inout' parameter '%1' in addition to other ~Escapable parameters",
+      // this arg list must be compatible with
+      // lifetime_dependence_cannot_infer_inout
+      (StringRef, StringRef))
 
 ERROR(lifetime_dependence_cannot_infer_return, none,
-      "%0 with a ~Escapable result requires '@lifetime(...)'", (StringRef))
+      "%0 with a ~Escapable result requires '@_lifetime(...)'", (StringRef))
 ERROR(lifetime_dependence_cannot_infer_mutating, none,
-      "%0 with a ~Escapable 'self' requires '@lifetime(self: ...)'", (StringRef))
+      "%0 with a ~Escapable 'self' requires '@_lifetime(self: ...)'", (StringRef))
 ERROR(lifetime_dependence_cannot_infer_inout, none,
-      "%0 with a ~Escapable 'inout' parameter requires '@lifetime(%1: ...)'",
-      (StringRef, Identifier))
+      "%0 with a ~Escapable 'inout' parameter requires '@_lifetime(%1: ...)'",
+      (StringRef, StringRef))
 
 //------------------------------------------------------------------------------
 // MARK: Lifetime Dependence Inference - refinements to the requirements above
@@ -8211,19 +8450,25 @@ ERROR(lifetime_dependence_cannot_infer_return_no_param, none,
       "%0 with a ~Escapable result needs a parameter to depend on",
       (StringRef))
 NOTE(lifetime_dependence_cannot_infer_return_immortal, none,
-     "'@lifetime(immortal)' can be used to indicate that values produced by "
+     "'@_lifetime(immortal)' can be used to indicate that values produced by "
      "this initializer have no lifetime dependencies", ())
 ERROR(lifetime_dependence_cannot_infer_bitwisecopyable, none,
       "cannot infer lifetime dependence on %0 because '%1' is BitwiseCopyable, "
-      "specify '@lifetime(borrow self)'",
+      "specify '@_lifetime(borrow self)'",
       (StringRef, StringRef))
 ERROR(lifetime_dependence_cannot_infer_kind, none,
       "cannot infer the lifetime dependence scope on %0 with a ~Escapable "
-      "parameter, specify '@lifetime(borrow %1)' or '@lifetime(copy %1)'",
+      "parameter, specify '@_lifetime(borrow %1)' or '@_lifetime(copy %1)'",
       (StringRef, StringRef))
 ERROR(lifetime_dependence_cannot_infer_scope_ownership, none,
       "cannot borrow the lifetime of '%0', which has consuming ownership on %1",
       (StringRef, StringRef))
+NOTE(lifetime_dependence_cannot_infer_inout_suggest, none,
+     "use '@_lifetime(%0: copy %0) to forward the inout dependency",
+     (StringRef))
+ERROR(lifetime_dependence_cannot_infer_implicit_init, none,
+      "cannot infer implicit initialization lifetime. Add an initializer with "
+      "'@_lifetime(...)' for each parameter the result depends on", ())
 
 //------------------------------------------------------------------------------
 // MARK: Lifetime Dependence Experimental Inference
@@ -8266,6 +8511,15 @@ NOTE(note_reference_to_unsafe_decl,none,
 NOTE(note_reference_to_unsafe_typed_decl,none,
      "%select{reference|call}0 to %kind1 involves unsafe type %2",
      (bool, const ValueDecl *, Type))
+NOTE(note_unsafe_call_decl_argument_named,none,
+     "argument %1 in call to %kindbase0 has unsafe type %2",
+     (const ValueDecl *, Identifier, Type))
+NOTE(note_unsafe_call_decl_argument_indexed,none,
+     "argument #%1 in call to %kindbase0 has unsafe type %2",
+     (const ValueDecl *, unsigned, Type))
+NOTE(note_unsafe_call_argument_indexed,none,
+     "argument #%0 in call has unsafe type %1",
+     (unsigned, Type))
 NOTE(note_reference_to_unsafe_through_typealias,none,
      "reference to %kind0 whose underlying type involves unsafe type %1",
      (const ValueDecl *, Type))
@@ -8278,9 +8532,10 @@ NOTE(note_reference_to_nonisolated_unsafe,none,
 NOTE(note_reference_unowned_unsafe,none,
      "reference to unowned(unsafe) %kind0 is unsafe", (const ValueDecl *))
 NOTE(note_reference_exclusivity_unchecked,none,
-     "reference to @exclusivity(unchecked) %kind0 is unsafe", (const ValueDecl *))
+     "reference to '@exclusivity(unchecked)' %kind0 is unsafe",
+     (const ValueDecl *))
 NOTE(note_use_of_unsafe_conformance_is_unsafe,none,
-     "@unsafe conformance of %0 to %kind1 involves unsafe code",
+     "'@unsafe' conformance of %0 to %kind1 involves unsafe code",
      (Type, const ValueDecl *))
 NOTE(note_unsafe_storage,none,
      "%kindbase1 involves unsafe type %2", (bool, const ValueDecl *, Type))
@@ -8298,7 +8553,7 @@ NOTE(decl_storage_mark_safe,none,
       "a safe interface", ())
 
 ERROR(safe_and_unsafe_attr,none,
-      "%kindbase0 cannot be both @safe and @unsafe", (const Decl *))
+      "%kindbase0 cannot be both '@safe' and '@unsafe'", (const Decl *))
 
 GROUPED_WARNING(unsafe_superclass,StrictMemorySafety,none,
      "%kindbase0 has superclass involving unsafe type %1", 
@@ -8309,28 +8564,30 @@ GROUPED_WARNING(conformance_involves_unsafe,StrictMemorySafety,none,
      "indicate that the conformance is not memory-safe",
      (Type, const ValueDecl *))
 NOTE(note_witness_unsafe,none,
-     "unsafe %0 %1 cannot satisfy safe requirement",
-      (DescriptiveDeclKind, DeclName))
+     "unsafe %kind0 cannot satisfy safe requirement",
+      (const ValueDecl *))
 NOTE(note_type_witness_unsafe,none,
       "unsafe type %0 cannot satisfy safe associated type %1",
       (Type, DeclName))
 
 GROUPED_WARNING(override_safe_with_unsafe,StrictMemorySafety,none,
-      "override of safe %0 with unsafe %0", (DescriptiveDeclKind))
+      "override of safe %kindonly0 with unsafe %kindonly0",
+      (const Decl *))
 
 GROUPED_WARNING(preconcurrency_import_unsafe,StrictMemorySafety,none,
-      "@preconcurrency import is not memory-safe because it can silently "
-      "introduce data races", ())
+      "'@preconcurrency' import is not memory-safe because it can silently "
+      "introduce data races; add '@unsafe' to indicate that this is unsafe", ())
 GROUPED_WARNING(unsafe_without_unsafe,StrictMemorySafety,none,
       "expression uses unsafe constructs but is not marked with 'unsafe'", ())
 GROUPED_WARNING(for_unsafe_without_unsafe,StrictMemorySafety,none,
       "for-in loop uses unsafe constructs but is not marked with 'unsafe'", ())
-GROUPED_WARNING(no_unsafe_in_unsafe,StrictMemorySafety,none,
+WARNING(no_unsafe_in_unsafe,none,
         "no unsafe operations occur within 'unsafe' expression", ())
-GROUPED_WARNING(no_unsafe_in_unsafe_for,StrictMemorySafety,none,
+WARNING(no_unsafe_in_unsafe_for,none,
         "no unsafe operations occur within 'unsafe' for-in loop", ())
 NOTE(make_subclass_unsafe,none,
-     "make class %0 @unsafe to allow unsafe overrides of safe superclass methods",
+     "make class %0 '@unsafe' to allow unsafe overrides of safe superclass "
+     "methods",
      (DeclName))
 
 //===----------------------------------------------------------------------===//
@@ -8343,8 +8600,8 @@ ERROR(value_type_used_in_type_parameter,none,
       "cannot use value type %0 for generic argument %1", (Type, Type))
 ERROR(invalid_value_type_value_generic,none,
       "%0 is not a supported value type for %1", (Type, Type))
-ERROR(invalid_value_generic_conformance,none,
-      "value generic type %0 cannot conform to protocol %1", (Type, Type))
+ERROR(invalid_value_generic_constraint,none,
+      "cannot use type constraint with generic value parameter %0", (Type))
 ERROR(invalid_value_generic_same_type,none,
       "cannot constrain value parameter %0 to be type %1", (Type, Type))
 ERROR(integer_type_not_accepted,none,
@@ -8369,13 +8626,37 @@ ERROR(inlinearray_literal_incorrect_count,none,
 ERROR(inline_array_type_backwards,none,
       "element count must precede inline array element type", ())
 
+//===----------------------------------------------------------------------===//
+// MARK: Embedded Swift
+//===----------------------------------------------------------------------===//
+
+GROUPED_ERROR(weak_unowned_in_embedded_swift, EmbeddedRestrictions, none,
+              "attribute %0 cannot be used in Embedded Swift",
+              (ReferenceOwnership))
+
+GROUPED_WARNING(untyped_throws_in_embedded_swift, EmbeddedRestrictions,
+                DefaultIgnore,
+                "untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'", ())
+GROUPED_WARNING(generic_nonfinal_in_embedded_swift, EmbeddedRestrictions,
+                DefaultIgnore,
+                "generic %kind0 in a class %select{must be 'final'|cannot be 'required'}1 in Embedded Swift",
+                (const Decl *, bool))
+GROUPED_WARNING(use_generic_member_of_existential_in_embedded_swift,
+                EmbeddedRestrictions, DefaultIgnore,
+                "cannot use generic %kind0 on a value of type %1 in Embedded Swift",
+                (const Decl *, Type))
+GROUPED_WARNING(dynamic_cast_involving_protocol_in_embedded_swift,
+                EmbeddedRestrictions, DefaultIgnore,
+                "cannot perform a dynamic cast to a type involving %kind0 in Embedded Swift",
+                (const Decl *))
+
 //===----------------------------------------------------------------------===//
 // MARK: @abi Attribute
 //===----------------------------------------------------------------------===//
 
 ERROR(attr_abi_mismatched_kind,none,
-      "cannot give %kind0 the ABI of a %1",
-      (Decl *, DescriptiveDeclKind))
+      "cannot give %kind0 the ABI of a %kindonly1",
+      (const Decl *, const Decl *))
 
 ERROR(attr_abi_mismatched_arity,none,
       "cannot give %kind0 the ABI of a %kindonly0 with a different number of "
@@ -8390,19 +8671,15 @@ ERROR(attr_abi_mismatched_async,none,
       "cannot give %0 the ABI of %select{a non-async|an async}1 %kindonly0",
       (Decl *, /*abiIsAsync=*/bool))
 
-ERROR(attr_abi_mismatched_pbd_size,none,
-      "cannot give pattern binding the ABI of a binding with "
-      "%select{more|fewer}0 patterns",
-      (/*abiHasExtra=*/bool))
-
-ERROR(attr_abi_mismatched_var,none,
-      "no match for %select{%kind0 in the ABI|ABI %kind0}1",
-      (Decl *, /*isABI=*/bool))
+ERROR(attr_abi_multiple_vars,none,
+      "'abi' attribute can only be applied to a single %0; declare each "
+      "%0 separately",
+      (DescriptiveDeclKind))
 
 ERROR(attr_abi_incompatible_with_silgen_name,none,
-      "cannot use '@_silgen_name' and '@abi' on the same %0 because they serve "
-      "the same purpose",
-      (DescriptiveDeclKind))
+      "cannot use '@_silgen_name' and '@abi' on the same %kindonly0 because "
+      "they serve the same purpose",
+      (const Decl *))
 
 ERROR(attr_abi_missing_attr,none,
       "missing '%0' %select{attribute|modifier}1 in '@abi'",
@@ -8413,9 +8690,6 @@ ERROR(attr_abi_extra_attr,none,
 ERROR(attr_abi_forbidden_attr,none,
       "unused '%0' %select{attribute|modifier}1 in '@abi'",
       (StringRef, bool))
-REMARK(abi_attr_inferred_attribute,none,
-       "inferred '%0' in '@abi' to match %select{attribute|modifier}1 on API",
-       (StringRef, bool))
 
 ERROR(attr_abi_mismatched_attr,none,
       "'%0' %select{attribute|modifier}1 in '@abi' should match '%2'",
@@ -8455,6 +8729,13 @@ ERROR(attr_abi_no_default_arguments,none,
       "affect the parameter's ABI",
       (Decl *))
 
+ERROR(attr_abi_no_macros,none,
+      "%kind0 cannot be expanded in '@abi' attribute",
+      (Decl *))
+ERROR(attr_abi_no_lazy,none,
+      "'lazy' is not compatible with '@abi' attribute",
+      ())
+
 // These macros insert 'final', 'non-final', or nothing depending on both the
 // current decl and its counterpart, such that 'non-final' is used if the
 // counterpart would be described as 'final' or 'static'. They must be kept in
@@ -8483,10 +8764,6 @@ ERROR(attr_abi_failable_mismatch,none,
 //===----------------------------------------------------------------------===//
 // MARK: Isolated conformances
 //===----------------------------------------------------------------------===//
-GROUPED_ERROR(isolated_conformance_experimental_feature,IsolatedConformances,
-      none,
-      "isolated conformances require experimental feature "
-      " 'IsolatedConformances'", ())
 NOTE(note_isolate_conformance_to_global_actor,none,
      "isolate this conformance to the %select{global actor %0|main actor}1 "
      "with '@%2'", (Type, bool, StringRef))
@@ -8505,45 +8782,99 @@ GROUPED_ERROR(isolated_conformance_with_sendable_simple,IsolatedConformances,
 GROUPED_ERROR(isolated_conformance_wrong_domain,IsolatedConformances,none,
       "%0 conformance of %1 to %2 cannot be used in %3 context",
       (ActorIsolation, Type, DeclName, ActorIsolation))
+GROUPED_WARNING(isolated_conformance_will_become_nonisolated,IsolatedConformances,none,
+      "conformance of %0 to %1 should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'",
+      (const ValueDecl *, const ValueDecl *))
+GROUPED_ERROR(isolated_conformance_to_sendable_metatype,IsolatedConformances,none,
+    "cannot form %0 conformance of %1 to SendableMetatype-inheriting %kind2",
+    (ActorIsolation, Type, const ValueDecl *))
 
 //===----------------------------------------------------------------------===//
-// MARK: @execution Attribute
+// MARK: @_inheritActorContext
 //===----------------------------------------------------------------------===//
+ERROR(inherit_actor_context_only_on_func_types,none,
+      "%0 only applies to parameters with function types (got: %1)",
+      (DeclAttribute, Type))
 
-ERROR(attr_execution_only_on_async,none,
-      "cannot use '@execution' on non-async %kind0",
-      (ValueDecl *))
+ERROR(inherit_actor_context_only_on_sending_or_Sendable_params,none,
+      "%0 only applies to 'sending' parameters or parameters with "
+      "'@Sendable' function types",
+      (DeclAttribute))
 
-ERROR(attr_execution_only_on_async_closure,none,
-      "cannot use '@execution' on non-async closure",
-      ())
+ERROR(inherit_actor_context_only_on_async_or_isolation_erased_params,none,
+      "%0 only applies to '@isolated(any)' parameters or parameters with "
+      "asynchronous function types",
+      (DeclAttribute))
 
-ERROR(attr_execution_type_attr_only_on_async,none,
-      "cannot use '@execution' on non-async function type",
-      ())
+//===----------------------------------------------------------------------===//
+// MARK: @concurrent and nonisolated(nonsending) attributes
+//===----------------------------------------------------------------------===//
 
-ERROR(attr_execution_incompatible_isolated_parameter,none,
-      "cannot use '@execution' on %kind0 because it has "
-      "an isolated parameter: %1",
-      (ValueDecl *, ValueDecl *))
+ERROR(execution_behavior_only_on_async,none,
+      "cannot use %0 on non-async %kind1",
+      (DeclAttribute, ValueDecl *))
 
-ERROR(attr_execution_incompatible_dynamically_isolated_parameter,none,
-      "cannot use '@execution' on %kind0 because it has "
-      "a dynamically isolated parameter: %1",
-      (ValueDecl *, ValueDecl *))
+ERROR(cannot_specify_execution_behavior_for_decl,none,
+      "%0 is only applicable to asynchronous functions, "
+      "initializers, subscripts and computed properties",
+      (DeclAttribute))
 
-ERROR(attr_execution_type_attr_incompatible_with_global_isolation,none,
-      "cannot use '@execution' because function type is "
-      "isolated to a global actor %0",
-      (Type))
+ERROR(execution_behavior_only_on_async_closure,none,
+      "cannot use %0 on non-async closure",
+      (DeclAttribute))
 
-ERROR(attr_execution_type_attr_incompatible_with_isolated_param,none,
-      "cannot use '@execution' together with an isolated parameter",
-      ())
+ERROR(execution_behavior_type_attr_only_on_async,none,
+      "cannot use '@%0' on non-async function type",
+      (StringRef))
 
-ERROR(attr_execution_type_attr_incompatible_with_isolated_any,none,
-      "cannot use '@execution' together with @isolated(any)",
-      ())
+ERROR(nonisolated_nonsending_only_on_function_types, none,
+      "%0 may only be used on function types",
+      (TypeRepr *))
+
+ERROR(nonisolated_nonsending_only_on_async,none,
+      "cannot use %0 on non-async function type",
+      (TypeRepr *))
+
+ERROR(cannot_use_nonisolated_nonsending_together_with_concurrent,none,
+      "cannot use %0 together with '@concurrent'",
+      (TypeRepr *))
+
+ERROR(execution_behavior_incompatible_isolated_parameter,none,
+      "cannot use %0 on %kind1 because it has "
+      "an isolated parameter: %2",
+      (DeclAttribute, ValueDecl *, ValueDecl *))
+
+ERROR(execution_behavior_attr_incompatible_with_global_isolation,none,
+      "cannot use %0 because function type is isolated to a global actor %1",
+      (DeclAttribute, Type))
+
+ERROR(execution_behavior_attr_incompatible_with_isolated_param,none,
+      "cannot use %0 together with an isolated parameter",
+      (DeclAttribute))
+
+ERROR(execution_behavior_type_attr_incompatible_with_global_isolation,none,
+      "cannot use '@%0' because function type is isolated to a global actor %1",
+      (StringRef, Type))
+
+ERROR(nonisolated_nonsending_incompatible_with_global_isolation,none,
+      "cannot use %0 because function type is isolated to a global actor %1",
+      (TypeRepr *, Type))
+
+ERROR(execution_behavior_type_attr_incompatible_with_isolated_param,none,
+      "cannot use '@%0' together with an isolated parameter",
+      (StringRef))
+
+ERROR(nonisolated_nonsending_incompatible_with_isolated_param,none,
+      "cannot use %0 together with an isolated parameter",
+      (TypeRepr *))
+
+ERROR(execution_behavior_type_attr_incompatible_with_isolated_any,none,
+      "cannot use '@%0' together with '@isolated(any)'",
+      (StringRef))
+
+ERROR(nonisolated_nonsending_incompatible_with_isolated_any,none,
+      "cannot use %0 together with '@isolated(any)'",
+      (TypeRepr *))
 
 ERROR(invalid_function_conversion_with_non_sendable,none,
       "cannot convert %0 to %1 because crossing of an isolation boundary "
@@ -8553,41 +8884,102 @@ NOTE(type_does_not_conform_to_Sendable,none,
      "type %0 does not conform to 'Sendable' protocol", (Type))
 
 GROUPED_WARNING(
-    attr_execution_nonisolated_behavior_will_change_decl, AsyncCallerExecution,
+    attr_execution_nonisolated_behavior_will_change_decl, NonisolatedNonsendingByDefault,
     none,
     "feature '%0' will cause nonisolated async %kindbase1 to run on the "
-    "caller's actor; use %2 to preserve behavior",
-    (StringRef, const AbstractFunctionDecl *, DeclAttribute))
+    "caller's actor; use '@concurrent' to preserve behavior",
+    (StringRef, const AbstractFunctionDecl *))
 
 GROUPED_WARNING(
     attr_execution_nonisolated_behavior_will_change_closure,
-    AsyncCallerExecution, none,
+    NonisolatedNonsendingByDefault, none,
     "feature '%0' will cause nonisolated async closure to run on the caller's "
-    "actor; use %1 to preserve behavior",
-    (StringRef, DeclAttribute))
+    "actor; use '@concurrent' to preserve behavior",
+    (StringRef))
 
 GROUPED_WARNING(
     attr_execution_nonisolated_behavior_will_change_typerepr,
-    AsyncCallerExecution, none,
+    NonisolatedNonsendingByDefault, none,
     "feature '%0' will cause nonisolated async function type to be treated as "
-    "specified to run on the caller's actor; use %1 to preserve "
+    "specified to run on the caller's actor; use '@concurrent' to preserve "
     "behavior",
-    (StringRef, DeclAttribute))
+    (StringRef))
 
 //===----------------------------------------------------------------------===//
-//                            MARK: SwiftSettings
+// MARK: @nonexhaustive and @preEnumExtensibility Attributes
 //===----------------------------------------------------------------------===//
 
-ERROR(swift_settings_invalid_setting, none,
-      "Unrecognized setting passed to #SwiftSettings", ())
+ERROR(nonexhaustive_attr_on_frozen_type,none,
+      "cannot use '@nonexhaustive' together with '@frozen'", ())
 
-ERROR(swift_settings_must_be_top_level, none,
-      "#SwiftSettings can only be invoked as a top level declaration", ())
+ERROR(nonexhaustive_attr_on_internal_type,none,
+      "'@nonexhaustive' attribute can only be applied to public or package "
+      "declarations, but %0 is "
+      "%select{private|fileprivate|internal|%error|%error|%error}1",
+      (DeclName, AccessLevel))
+
+//===----------------------------------------------------------------------===//
+// MARK: `using` declaration
+//===----------------------------------------------------------------------===//
+ERROR(invalid_redecl_of_file_isolation,none,
+      "invalid redeclaration of file-level default actor isolation", ())
+NOTE(invalid_redecl_of_file_isolation_prev,none,
+     "default isolation was previously declared here", ())
+
+//===----------------------------------------------------------------------===//
+// MARK: `@inline(always)` attribute
+//===----------------------------------------------------------------------===//
+ERROR(attr_inline_always_experimental,none,
+      "'@inline(always)' is an experimental feature", ())
+ERROR(attr_inline_always_requires_inlinable,none,
+      "'@inline(always)' on public or package declarations must be used "
+      "together with '@inlinable'", ())
+ERROR(attr_inline_always_no_usable_from_inline,none,
+      "cannot use '@inline(always)' together with '@usableFromInline'", ())
+ERROR(attr_inline_always_requires_final_method,none,
+      "'@inline(always)' on class %select{methods|vars}1 requires %0 to be "
+      "marked 'final'", (DeclName, bool))
+ERROR(attr_inline_always_on_accessor,none,
+      "'@inline(always)' on class variable accessors whose variable declaration"
+      " is not final are not allowed", ())
+
+//===----------------------------------------------------------------------===//
+// MARK: Swift Performance hints
+//===----------------------------------------------------------------------===//
 
-ERROR(swift_settings_duplicate_setting, none,
-      "duplicate setting passed to #SwiftSettings", ())
-NOTE(swift_settings_duplicate_setting_original_loc, none,
-     "setting originally passed here", ())
+GROUPED_WARNING(perf_hint_function_returns_array,ReturnTypeImplicitCopy,DefaultIgnore,
+                "Performance: %0 returns a%select{ dictionary|n array}1, leading to implicit copies. "
+                "Consider using an 'inout' parameter instead.", (const FuncDecl *, bool))
+GROUPED_WARNING(perf_hint_closure_returns_array,ReturnTypeImplicitCopy,DefaultIgnore,
+                "Performance: closure returns a%select{ dictionary|n array}0, leading to implicit copies. "
+                "Consider using an 'inout' parameter instead.", (bool))
+
+GROUPED_WARNING(perf_hint_param_expects_existential,ExistentialType,DefaultIgnore,
+                "Performance: %0 expects an existential, leading to heap allocation, reference counting, "
+                "and dynamic dispatch. Consider using generic constraints or concrete types instead.",
+                (const ParamDecl*))
+GROUPED_WARNING(perf_hint_func_returns_existential,ExistentialType,DefaultIgnore,
+                "Performance: %0 returns an existential, leading to heap allocation, reference counting, "
+                "and dynamic dispatch. Consider using generic constraints or concrete types instead.",
+                (const FuncDecl*))
+GROUPED_WARNING(perf_hint_closure_returns_existential,ExistentialType,DefaultIgnore,
+                "Performance: closure returns an existential, leading to heap allocation, reference counting, "
+                "and dynamic dispatch. Consider using generic constraints or concrete types instead.", ())
+GROUPED_WARNING(perf_hint_var_uses_existential,ExistentialType,DefaultIgnore,
+                "Performance: %0 uses an existential, leading to heap allocation, reference counting, "
+                "and dynamic dispatch. Consider using generic constraints or concrete types instead.",
+                (const VarDecl *))
+GROUPED_WARNING(perf_hint_any_pattern_uses_existential,ExistentialType,DefaultIgnore,
+                "Performance: declaration uses an existential, leading to heap allocation, reference counting, "
+                "and dynamic dispatch. Consider using generic constraints or concrete types instead.",
+                ())
+GROUPED_WARNING(perf_hint_typealias_uses_existential,ExistentialType,DefaultIgnore,
+                "Performance: %0 aliases an existential type, leading to heap allocation, reference counting, "
+                "and dynamic dispatch. Consider using generic constraints or concrete types instead.",
+                (const TypeAliasDecl *))
+
+ERROR(unsafe_self_dependent_result_attr_on_invalid_decl,none,
+      "invalid use of @_unsafeSelfDependentResult", ())
 
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"
diff --git a/include/swift/AST/DiagnosticsSema.h b/include/swift/AST/DiagnosticsSema.h
index 90c9ac89107a5..44c6893da0df3 100644
--- a/include/swift/AST/DiagnosticsSema.h
+++ b/include/swift/AST/DiagnosticsSema.h
@@ -21,7 +21,6 @@
 #include "swift/AST/DiagnosticsCommon.h"
 
 namespace swift {
-  class SwitchStmt;
   namespace diag {
 
     /// Describes the kind of requirement in a protocol.
diff --git a/include/swift/AST/Evaluator.h b/include/swift/AST/Evaluator.h
index f3f56f0f85ae2..5d7e47f29e65c 100644
--- a/include/swift/AST/Evaluator.h
+++ b/include/swift/AST/Evaluator.h
@@ -22,6 +22,7 @@
 #include "swift/AST/EvaluatorDependencies.h"
 #include "swift/AST/RequestCache.h"
 #include "swift/Basic/AnyValue.h"
+#include "swift/Basic/Assertions.h"
 #include "swift/Basic/Debug.h"
 #include "swift/Basic/LangOptions.h"
 #include "swift/Basic/Statistic.h"
@@ -163,6 +164,9 @@ class Evaluator {
   /// is treated as a stack and is used to detect cycles.
   llvm::SetVector<ActiveRequest> activeRequests;
 
+  /// A set of active requests that have been diagnosed for a cycle.
+  llvm::DenseSet<ActiveRequest> diagnosedActiveCycles;
+
   /// A cache that stores the results of requests.
   evaluator::RequestCache cache;
 
@@ -208,6 +212,7 @@ class Evaluator {
   void enumerateReferencesInFile(
       const SourceFile *SF,
       evaluator::DependencyRecorder::ReferenceEnumerator f) const {
+    ASSERT(recorder.isRecordingEnabled() && "Dep recording should be enabled");
     return recorder.enumerateReferencesInFile(SF, f);
   }
 
@@ -276,9 +281,7 @@ class Evaluator {
            typename std::enable_if<Request::hasSplitCache>::type* = nullptr>
   void cacheNonEmptyOutput(const Request &request,
                            typename Request::OutputType &&output) {
-    bool inserted = cache.insert<Request>(request, std::move(output));
-    assert(inserted && "Request result was already cached");
-    (void) inserted;
+    (void)cache.insert<Request>(request, std::move(output));
   }
 
   /// Consults the request evaluator's cache for a split-cached request.
@@ -344,7 +347,17 @@ class Evaluator {
 
     recorder.beginRequest<Request>();
 
-    auto result = getRequestFunction<Request>()(request, *this);
+    auto result = [&]() -> typename Request::OutputType {
+      auto reqResult = getRequestFunction<Request>()(request, *this);
+
+      // If we diagnosed a cycle for this request, we want to only use the
+      // default value to ensure we return a consistent result.
+      if (!diagnosedActiveCycles.empty() &&
+          diagnosedActiveCycles.erase(activeReq)) {
+        return defaultValueFn();
+      }
+      return reqResult;
+    }();
 
     recorder.endRequest<Request>(request);
 
@@ -416,6 +429,8 @@ class Evaluator {
             typename std::enable_if<Request::isDependencySink>::type * = nullptr>
   void handleDependencySinkRequest(const Request &r,
                                    const typename Request::OutputType &o) {
+    if (!recorder.isRecordingEnabled())
+      return;
     evaluator::DependencyCollector collector(recorder);
     r.writeDependencySink(collector, o);
   }
@@ -427,6 +442,8 @@ class Evaluator {
   template <typename Request,
             typename std::enable_if<Request::isDependencySource>::type * = nullptr>
   void handleDependencySourceRequest(const Request &r) {
+    if (!recorder.isRecordingEnabled())
+      return;
     auto source = r.readDependencySource(recorder);
     if (!source.isNull() && source.get()->isPrimary()) {
       recorder.handleDependencySourceRequest(r, source.get());
diff --git a/include/swift/AST/EvaluatorDependencies.h b/include/swift/AST/EvaluatorDependencies.h
index 89fc27441c888..91fcf8cd9d1b1 100644
--- a/include/swift/AST/EvaluatorDependencies.h
+++ b/include/swift/AST/EvaluatorDependencies.h
@@ -94,6 +94,9 @@ class DependencyRecorder {
 public:
   DependencyRecorder(bool shouldRecord) : shouldRecord(shouldRecord) {}
 
+  /// Whether dependency recording is enabled.
+  bool isRecordingEnabled() const { return shouldRecord; }
+
   /// Push a new empty set onto the activeRequestReferences stack.
   template<typename Request>
   void beginRequest();
diff --git a/include/swift/AST/ExistentialLayout.h b/include/swift/AST/ExistentialLayout.h
index 706e6341379df..ad45c33a5e379 100644
--- a/include/swift/AST/ExistentialLayout.h
+++ b/include/swift/AST/ExistentialLayout.h
@@ -105,6 +105,9 @@ struct ExistentialLayout {
   /// calling this on a temporary is likely to be incorrect.
   ArrayRef<ProtocolDecl*> getProtocols() const && = delete;
 
+  /// Determine whether this refers to any non-marker protocols.
+  bool containsNonMarkerProtocols() const;
+
   ArrayRef<ParameterizedProtocolType *> getParameterizedProtocols() const & {
     return parameterized;
   }
@@ -114,9 +117,24 @@ struct ExistentialLayout {
 
   LayoutConstraint getLayoutConstraint() const;
 
+  /// Whether this layout has any inverses within its signature.
+  bool hasInverses() const {
+    return !inverses.empty();
+  }
+
+  /// Whether this existential needs to have an extended existential shape. This
+  /// is relevant for the mangler to mangle as a symbolic link where possible
+  /// and for IRGen directly emitting some existentials.
+  ///
+  /// If 'allowInverses' is false, then regardless of if this existential layout
+  /// has inverse requirements those will not influence the need for having a
+  /// shape.
+  bool needsExtendedShape(bool allowInverses = true) const;
+
 private:
   SmallVector<ProtocolDecl *, 4> protocols;
   SmallVector<ParameterizedProtocolType *, 4> parameterized;
+  InvertibleProtocolSet inverses;
 };
 
 }
diff --git a/include/swift/AST/Expr.h b/include/swift/AST/Expr.h
index 7515022f3dc91..bb370c0b332c8 100644
--- a/include/swift/AST/Expr.h
+++ b/include/swift/AST/Expr.h
@@ -154,12 +154,12 @@ class alignas(8) Expr : public ASTAllocated<Expr> {
     Implicit : 1
   );
 
-  SWIFT_INLINE_BITFIELD_FULL(CollectionExpr, Expr, 64-NumExprBits,
+  SWIFT_INLINE_BITFIELD_FULL(CollectionExpr, Expr, 64-NumberOfExprBits,
     /// True if the type of this collection expr was inferred by the collection
     /// fallback type, like [Any].
     IsTypeDefaulted : 1,
     /// Number of comma source locations.
-    NumCommas : 32 - 1 - NumExprBits,
+    NumCommas : 32 - 1 - NumberOfExprBits,
     /// Number of entries in the collection. If this is a DictionaryExpr,
     /// each entry is a Tuple with the key and value pair.
     NumSubExprs : 32
@@ -256,8 +256,8 @@ class alignas(8) Expr : public ASTAllocated<Expr> {
     LitKind : 3
   );
 
-  SWIFT_INLINE_BITFIELD(AbstractClosureExpr, Expr, (16-NumExprBits)+16,
-    : 16 - NumExprBits, // Align and leave room for subclasses
+  SWIFT_INLINE_BITFIELD(AbstractClosureExpr, Expr, (16-NumberOfExprBits)+16,
+    : 16 - NumberOfExprBits, // Align and leave room for subclasses
     Discriminator : 16
   );
 
@@ -267,7 +267,7 @@ class alignas(8) Expr : public ASTAllocated<Expr> {
     Kind : 2
   );
 
-  SWIFT_INLINE_BITFIELD(ClosureExpr, AbstractClosureExpr, 1+1+1+1+1+1+1,
+  SWIFT_INLINE_BITFIELD(ClosureExpr, AbstractClosureExpr, 1+1+1+1+1+1+1+1+1,
     /// True if closure parameters were synthesized from anonymous closure
     /// variables.
     HasAnonymousClosureVars : 1,
@@ -276,9 +276,11 @@ class alignas(8) Expr : public ASTAllocated<Expr> {
     /// on each member reference.
     ImplicitSelfCapture : 1,
 
-    /// True if this @Sendable async closure parameter should implicitly
-    /// inherit the actor context from where it was formed.
+    /// True if this closure parameter should implicitly inherit the actor
+    /// context from where it was formed.
     InheritActorContext : 1,
+    /// The kind for inheritance - none or always at the moment.
+    InheritActorContextKind : 1,
 
     /// True if this closure's actor isolation behavior was determined by an
     /// \c \@preconcurrency declaration.
@@ -295,7 +297,12 @@ class alignas(8) Expr : public ASTAllocated<Expr> {
     /// isolation checks when it either specifies or inherits isolation
     /// and was passed as an argument to a function that is not fully 
     /// concurrency checked.
-    RequiresDynamicIsolationChecking : 1
+    RequiresDynamicIsolationChecking : 1,
+
+    /// Whether this closure was type-checked as an argument to a macro. This
+    /// is only populated after type-checking, and only exists for diagnostic
+    /// logic. Do not add more uses of this.
+    IsMacroArgument : 1
   );
 
   SWIFT_INLINE_BITFIELD_FULL(BindOptionalExpr, Expr, 16,
@@ -603,7 +610,8 @@ class ErrorExpr : public Expr {
 
   SourceRange getSourceRange() const { return Range; }
   Expr *getOriginalExpr() const { return OriginalExpr; }
-  
+  void setOriginalExpr(Expr *newExpr) { OriginalExpr = newExpr; }
+
   static bool classof(const Expr *E) {
     return E->getKind() == ExprKind::Error;
   }
@@ -689,9 +697,7 @@ class BuiltinLiteralExpr : public LiteralExpr {
 
   /// Set the builtin initializer that will be used to construct the
   /// literal.
-  void setBuiltinInitializer(ConcreteDeclRef builtinInitializer) {
-    BuiltinInitializer = builtinInitializer;
-  }
+  void setBuiltinInitializer(ConcreteDeclRef builtinInitializer);
 };
 
 /// The 'nil' literal.
@@ -1449,23 +1455,25 @@ class TypeExpr : public Expr {
 };
 
 class TypeValueExpr : public Expr {
-  GenericTypeParamDecl *paramDecl;
-  DeclNameLoc loc;
+  TypeRepr *repr;
   Type paramType;
 
-  /// Create a \c TypeValueExpr from a given generic value param decl.
-  TypeValueExpr(DeclNameLoc loc, GenericTypeParamDecl *paramDecl) :
-      Expr(ExprKind::TypeValue, /*implicit*/ false), paramDecl(paramDecl),
-      loc(loc), paramType(nullptr) {}
+  /// Create a \c TypeValueExpr from a given type representation.
+  TypeValueExpr(TypeRepr *repr) :
+      Expr(ExprKind::TypeValue, /*implicit*/ false), repr(repr),
+      paramType(nullptr) {}
 
 public:
-  /// Create a \c TypeValueExpr for a given \c GenericTypeParamDecl.
+  /// Create a \c TypeValueExpr for a given \c TypeDecl.
   ///
   /// The given location must be valid.
-  static TypeValueExpr *createForDecl(DeclNameLoc Loc, GenericTypeParamDecl *D);
+  static TypeValueExpr *createForDecl(DeclNameLoc loc, TypeDecl *d,
+                                      DeclContext *dc);
+
+  GenericTypeParamDecl *getParamDecl() const;
 
-  GenericTypeParamDecl *getParamDecl() const {
-    return paramDecl;
+  TypeRepr *getRepr() const {
+    return repr;
   }
 
   /// Retrieves the corresponding parameter type of the value referenced by this
@@ -1480,9 +1488,7 @@ class TypeValueExpr : public Expr {
     this->paramType = paramType;
   }
 
-  SourceRange getSourceRange() const {
-    return loc.getSourceRange();
-  }
+  SourceRange getSourceRange() const;
 
   static bool classof(const Expr *E) {
     return E->getKind() == ExprKind::TypeValue;
@@ -3287,8 +3293,7 @@ class DestructureTupleExpr final : public ImplicitConversionExpr,
       DstExpr(dstExpr) {
     Bits.DestructureTupleExpr.NumElements = destructuredElements.size();
     std::uninitialized_copy(destructuredElements.begin(),
-                            destructuredElements.end(),
-                            getTrailingObjects<OpaqueValueExpr *>());
+                            destructuredElements.end(), getTrailingObjects());
   }
 
 public:
@@ -3300,8 +3305,8 @@ class DestructureTupleExpr final : public ImplicitConversionExpr,
          Expr *srcExpr, Expr *dstExpr, Type ty);
 
   ArrayRef<OpaqueValueExpr *> getDestructuredElements() const {
-    return {getTrailingObjects<OpaqueValueExpr *>(),
-            static_cast<size_t>(Bits.DestructureTupleExpr.NumElements)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.DestructureTupleExpr.NumElements));
   }
 
   Expr *getResultExpr() const {
@@ -3342,24 +3347,9 @@ class ABISafeConversionExpr : public ImplicitConversionExpr {
   }
 };
 
-/// This is a conversion from an expression of UnresolvedType to an arbitrary
-/// other type, and from an arbitrary type to UnresolvedType.  This node does
-/// not appear in valid code, only in code involving diagnostics.
-class UnresolvedTypeConversionExpr : public ImplicitConversionExpr {
-public:
-  UnresolvedTypeConversionExpr(Expr *subExpr, Type type)
-  : ImplicitConversionExpr(ExprKind::UnresolvedTypeConversion, subExpr, type) {}
-
-  static bool classof(const Expr *E) {
-    return E->getKind() == ExprKind::UnresolvedTypeConversion;
-  }
-};
-
 /// FunctionConversionExpr - Convert a function to another function type,
 /// which might involve renaming the parameters or handling substitutions
 /// of subtypes (in the return) or supertypes (in the input).
-///
-/// FIXME: This should be a CapturingExpr.
 class FunctionConversionExpr : public ImplicitConversionExpr {
 public:
   FunctionConversionExpr(Expr *subExpr, Type type)
@@ -3721,7 +3711,7 @@ class UnresolvedSpecializeExpr final : public Expr,
       SubExpr(SubExpr), LAngleLoc(LAngleLoc), RAngleLoc(RAngleLoc) {
     Bits.UnresolvedSpecializeExpr.NumUnresolvedParams = UnresolvedParams.size();
     std::uninitialized_copy(UnresolvedParams.begin(), UnresolvedParams.end(),
-                            getTrailingObjects<TypeRepr *>());
+                            getTrailingObjects());
   }
 
 public:
@@ -3735,8 +3725,8 @@ class UnresolvedSpecializeExpr final : public Expr,
   /// Retrieve the list of type parameters. These parameters have not yet
   /// been bound to archetypes of the entity to be specialized.
   ArrayRef<TypeRepr *> getUnresolvedParams() const {
-    return {getTrailingObjects<TypeRepr *>(),
-            static_cast<size_t>(Bits.UnresolvedSpecializeExpr.NumUnresolvedParams)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.UnresolvedSpecializeExpr.NumUnresolvedParams));
   }
   
   SourceLoc getLoc() const { return LAngleLoc; }
@@ -3993,7 +3983,7 @@ class SequenceExpr final : public Expr,
     Bits.SequenceExpr.NumElements = elements.size();
     assert(Bits.SequenceExpr.NumElements > 0 && "zero-length sequence!");
     std::uninitialized_copy(elements.begin(), elements.end(),
-                            getTrailingObjects<Expr*>());
+                            getTrailingObjects());
   }
 
 public:
@@ -4009,11 +3999,13 @@ class SequenceExpr final : public Expr,
   unsigned getNumElements() const { return Bits.SequenceExpr.NumElements; }
 
   MutableArrayRef<Expr*> getElements() {
-    return {getTrailingObjects<Expr*>(), static_cast<size_t>(Bits.SequenceExpr.NumElements)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.SequenceExpr.NumElements));
   }
 
   ArrayRef<Expr*> getElements() const {
-    return {getTrailingObjects<Expr*>(), static_cast<size_t>(Bits.SequenceExpr.NumElements)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.SequenceExpr.NumElements));
   }
 
   Expr *getElement(unsigned i) const {
@@ -4313,9 +4305,11 @@ class ClosureExpr : public AbstractClosureExpr {
     Bits.ClosureExpr.HasAnonymousClosureVars = false;
     Bits.ClosureExpr.ImplicitSelfCapture = false;
     Bits.ClosureExpr.InheritActorContext = false;
+    Bits.ClosureExpr.InheritActorContextKind = 0;
     Bits.ClosureExpr.IsPassedToSendingParameter = false;
     Bits.ClosureExpr.NoGlobalActorAttribute = false;
     Bits.ClosureExpr.RequiresDynamicIsolationChecking = false;
+    Bits.ClosureExpr.IsMacroArgument = false;
   }
 
   SourceRange getSourceRange() const;
@@ -4360,8 +4354,29 @@ class ClosureExpr : public AbstractClosureExpr {
     return Bits.ClosureExpr.InheritActorContext;
   }
 
-  void setInheritsActorContext(bool value = true) {
+  /// Whether this closure should _always_ implicitly inherit the actor context
+  /// regardless of whether the isolation parameter is captured or not.
+  bool alwaysInheritsActorContext() const {
+    if (!inheritsActorContext())
+      return false;
+    return getInheritActorIsolationModifier() ==
+           InheritActorContextModifier::Always;
+  }
+
+  void setInheritsActorContext(bool value = true,
+                               InheritActorContextModifier modifier =
+                                   InheritActorContextModifier::None) {
     Bits.ClosureExpr.InheritActorContext = value;
+    Bits.ClosureExpr.InheritActorContextKind = uint8_t(modifier);
+    assert((static_cast<InheritActorContextModifier>(
+                Bits.ClosureExpr.InheritActorContextKind) == modifier) &&
+           "not enough bits for modifier");
+  }
+
+  InheritActorContextModifier getInheritActorIsolationModifier() const {
+    assert(inheritsActorContext());
+    return static_cast<InheritActorContextModifier>(
+        Bits.ClosureExpr.InheritActorContextKind);
   }
 
   /// Whether the closure's concurrency behavior was determined by an
@@ -4394,6 +4409,17 @@ class ClosureExpr : public AbstractClosureExpr {
     Bits.ClosureExpr.RequiresDynamicIsolationChecking = value;
   }
 
+  /// Whether this closure was type-checked as an argument to a macro. This
+  /// is only populated after type-checking, and only exists for diagnostic
+  /// logic. Do not add more uses of this.
+  bool isMacroArgument() const {
+    return Bits.ClosureExpr.IsMacroArgument;
+  }
+
+  void setIsMacroArgument(bool value = true) {
+    Bits.ClosureExpr.IsMacroArgument = value;
+  }
+
   /// Determine whether this closure expression has an
   /// explicitly-specified result type.
   bool hasExplicitResultType() const { return ArrowLoc.isValid(); }
@@ -4616,7 +4642,7 @@ class CaptureListExpr final : public Expr,
     assert(closureBody);
     Bits.CaptureListExpr.NumCaptures = captureList.size();
     std::uninitialized_copy(captureList.begin(), captureList.end(),
-                            getTrailingObjects<CaptureListEntry>());
+                            getTrailingObjects());
   }
 
 public:
@@ -4625,8 +4651,8 @@ class CaptureListExpr final : public Expr,
                                  AbstractClosureExpr *closureBody);
 
   ArrayRef<CaptureListEntry> getCaptureList() {
-    return {getTrailingObjects<CaptureListEntry>(),
-            static_cast<size_t>(Bits.CaptureListExpr.NumCaptures)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.CaptureListExpr.NumCaptures));
   }
   AbstractClosureExpr *getClosureBody() { return closureBody; }
   const AbstractClosureExpr *getClosureBody() const { return closureBody; }
@@ -6472,16 +6498,20 @@ class KeyPathDotExpr : public Expr {
   }
 };
 
+struct ForCollectionInit {
+  VarDecl *ForAccumulatorDecl;
+  PatternBindingDecl *ForAccumulatorBinding;
+};
+
 /// An expression that may wrap a statement which produces a single value.
 class SingleValueStmtExpr : public Expr {
 public:
-  enum class Kind {
-    If, Switch, Do, DoCatch
-  };
+  enum class Kind { If, Switch, Do, DoCatch, For };
 
 private:
   Stmt *S;
   DeclContext *DC;
+  std::optional<ForCollectionInit> ForExpressionPreamble;
 
   SingleValueStmtExpr(Stmt *S, DeclContext *DC)
       : Expr(ExprKind::SingleValueStmt, /*isImplicit*/ true), S(S), DC(DC) {}
@@ -6546,6 +6576,14 @@ class SingleValueStmtExpr : public Expr {
 
   SourceRange getSourceRange() const;
 
+  std::optional<ForCollectionInit> getForExpressionPreamble() const {
+    return this->ForExpressionPreamble;
+  }
+
+  void setForExpressionPreamble(ForCollectionInit newPreamble) {
+    this->ForExpressionPreamble = newPreamble;
+  }
+
   static bool classof(const Expr *E) {
     return E->getKind() == ExprKind::SingleValueStmt;
   }
@@ -6566,7 +6604,7 @@ class TypeJoinExpr final : public Expr,
   }
 
   MutableArrayRef<Expr *> getMutableElements() {
-    return { getTrailingObjects<Expr *>(), getNumElements() };
+    return getTrailingObjects(getNumElements());
   }
 
   TypeJoinExpr(llvm::PointerUnion<DeclRefExpr *, TypeBase *> result,
@@ -6609,7 +6647,7 @@ class TypeJoinExpr final : public Expr,
   }
 
   ArrayRef<Expr *> getElements() const {
-    return { getTrailingObjects<Expr *>(), getNumElements() };
+    return getTrailingObjects(getNumElements());
   }
 
   Expr *getElement(unsigned i) const {
diff --git a/include/swift/AST/ExprNodes.def b/include/swift/AST/ExprNodes.def
index 6a2e250d865fb..a193b8d699ec0 100644
--- a/include/swift/AST/ExprNodes.def
+++ b/include/swift/AST/ExprNodes.def
@@ -161,7 +161,6 @@ ABSTRACT_EXPR(ImplicitConversion, Expr)
   EXPR(Load, ImplicitConversionExpr)
   EXPR(ABISafeConversion, ImplicitConversionExpr)
   EXPR(DestructureTuple, ImplicitConversionExpr)
-  EXPR(UnresolvedTypeConversion, ImplicitConversionExpr)
   EXPR(FunctionConversion, ImplicitConversionExpr)
   EXPR(CovariantFunctionConversion, ImplicitConversionExpr)
   EXPR(CovariantReturnConversion, ImplicitConversionExpr)
diff --git a/include/swift/AST/ExtInfo.h b/include/swift/AST/ExtInfo.h
index 3662a99c61aef..28f30af1d870b 100644
--- a/include/swift/AST/ExtInfo.h
+++ b/include/swift/AST/ExtInfo.h
@@ -67,17 +67,17 @@ class FunctionTypeIsolation {
     /// Inherits isolation from the caller. This is only applicable
     /// to asynchronous function types.
     ///
-    /// NOTE: The difference in between NonIsolatedCaller and
-    /// NonIsolated is that NonIsolatedCaller is a strictly
+    /// NOTE: The difference in between NonIsolatedNonsending and
+    /// NonIsolated is that NonIsolatedNonsending is a strictly
     /// weaker form of nonisolation. While both in their bodies cannot
-    /// access isolated state directly, NonIsolatedCaller functions
+    /// access isolated state directly, NonIsolatedNonsending functions
     /// /are/ allowed to access state isolated to their caller via
     /// function arguments since we know that the callee will stay
     /// in the caller's isolation domain. In contrast, NonIsolated
     /// is strongly nonisolated and is not allowed to access /any/
     /// isolated state (even via function parameters) since it is
     /// considered safe to run on /any/ actor.
-    NonIsolatedCaller,
+    NonIsolatedNonsending,
   };
 
   static constexpr size_t NumBits = 3; // future-proof this slightly
@@ -103,7 +103,7 @@ class FunctionTypeIsolation {
     return { Kind::Erased };
   }
   static FunctionTypeIsolation forNonIsolatedCaller() {
-    return { Kind::NonIsolatedCaller };
+    return { Kind::NonIsolatedNonsending };
   }
 
   Kind getKind() const { return value.getInt(); }
@@ -124,7 +124,27 @@ class FunctionTypeIsolation {
     return getKind() == Kind::Erased;
   }
   bool isNonIsolatedCaller() const {
-    return getKind() == Kind::NonIsolatedCaller;
+    return getKind() == Kind::NonIsolatedNonsending;
+  }
+
+  /// Two function type isolations are equal if they have the same kind and
+  /// (when applicable) the same global actor types.
+  ///
+  /// Exact equality is the right thing to ask about when deciding whether
+  /// two isolations are the same statically, because we have to treat
+  /// different specializations of the same generic global actor type
+  /// as potentially different isolations. (Of course, you must be comparing
+  /// types that have been mapped into the same context.)
+  ///
+  /// Exact equality is *not* the right thing to ask about when deciding
+  /// whether two isolations might be the same dynamically, because two
+  /// different specializations of the same generic global actor type
+  /// could absolutely end up being the same in concrete specialization.
+  bool operator==(FunctionTypeIsolation other) const {
+    return value == other.value;
+  }
+  bool operator!=(FunctionTypeIsolation other) const {
+    return value != other.value;
   }
 
   // The opaque accessors below are just for the benefit of ExtInfoBuilder,
@@ -517,7 +537,8 @@ class ASTExtInfoBuilder {
     DifferentiabilityMaskOffset = 11,
     DifferentiabilityMask = 0x7 << DifferentiabilityMaskOffset,
     SendingResultMask = 1 << 14,
-    NumMaskBits = 15
+    InOutResultMask = 1 << 15,
+    NumMaskBits = 16
   };
 
   static_assert(FunctionTypeIsolation::Mask == 0x7, "update mask manually");
@@ -549,7 +570,7 @@ class ASTExtInfoBuilder {
       : ASTExtInfoBuilder(Representation::Swift, false, false, Type(),
                           DifferentiabilityKind::NonDifferentiable, nullptr,
                           FunctionTypeIsolation::forNonIsolated(),
-                          std::nullopt /* LifetimeDependenceInfo */,
+                          {} /* LifetimeDependenceInfo */,
                           false /*sendingResult*/) {}
 
   // Constructor for polymorphic type.
@@ -557,7 +578,7 @@ class ASTExtInfoBuilder {
       : ASTExtInfoBuilder(rep, false, throws, thrownError,
                           DifferentiabilityKind::NonDifferentiable, nullptr,
                           FunctionTypeIsolation::forNonIsolated(),
-                          std::nullopt /* LifetimeDependenceInfo */,
+                          {} /* LifetimeDependenceInfo */,
                           false /*sendingResult*/) {}
 
   // Constructor with no defaults.
@@ -640,6 +661,8 @@ class ASTExtInfoBuilder {
                                                    globalActor);
   }
 
+  constexpr bool hasInOutResult() const { return bits & InOutResultMask; }
+
   constexpr bool hasSelfParam() const {
     switch (getSILRepresentation()) {
     case SILFunctionTypeRepresentation::Thick:
@@ -740,12 +763,19 @@ class ASTExtInfoBuilder {
                              globalActor, thrownError, lifetimeDependencies);
   }
 
+  /// \p lifetimeDependencies should be arena allocated and not a temporary
+  /// Function types are allocated on the are arena and their ExtInfo should be
+  /// valid throughout their lifetime.
   [[nodiscard]] ASTExtInfoBuilder withLifetimeDependencies(
       llvm::ArrayRef<LifetimeDependenceInfo> lifetimeDependencies) const {
     return ASTExtInfoBuilder(bits, clangTypeInfo, globalActor, thrownError,
                              lifetimeDependencies);
   }
 
+  [[nodiscard]] ASTExtInfoBuilder withLifetimeDependencies(
+      SmallVectorImpl<LifetimeDependenceInfo> lifetimeDependencies) const =
+      delete;
+
   [[nodiscard]]
   ASTExtInfoBuilder withIsolation(FunctionTypeIsolation isolation) const {
     return ASTExtInfoBuilder(
@@ -755,6 +785,11 @@ class ASTExtInfoBuilder {
         lifetimeDependencies);
   }
 
+  [[nodiscard]] ASTExtInfoBuilder withHasInOutResult() const {
+    return ASTExtInfoBuilder((bits | InOutResultMask), clangTypeInfo,
+                             globalActor, thrownError, lifetimeDependencies);
+  }
+
   void Profile(llvm::FoldingSetNodeID &ID) const {
     ID.AddInteger(bits);
     ID.AddPointer(clangTypeInfo.getType());
@@ -850,6 +885,8 @@ class ASTExtInfo {
 
   FunctionTypeIsolation getIsolation() const { return builder.getIsolation(); }
 
+  constexpr bool hasInOutResult() const { return builder.hasInOutResult(); }
+
   /// Helper method for changing the representation.
   ///
   /// Prefer using \c ASTExtInfoBuilder::withRepresentation for chaining.
@@ -920,11 +957,18 @@ class ASTExtInfo {
       .build();
   }
 
+  /// \p lifetimeDependencies should be arena allocated and not a temporary
+  /// Function types are allocated on the are arena and their ExtInfo should be
+  /// valid throughout their lifetime.
   [[nodiscard]] ASTExtInfo withLifetimeDependencies(
       ArrayRef<LifetimeDependenceInfo> lifetimeDependencies) const {
     return builder.withLifetimeDependencies(lifetimeDependencies).build();
   }
 
+  [[nodiscard]] ASTExtInfo withLifetimeDependencies(
+      SmallVectorImpl<LifetimeDependenceInfo> lifetimeDependencies) const =
+      delete;
+
   void Profile(llvm::FoldingSetNodeID &ID) const { builder.Profile(ID); }
 
   bool isEqualTo(ASTExtInfo other, bool useClangTypes) const {
@@ -1033,7 +1077,7 @@ class SILExtInfoBuilder {
             makeBits(SILFunctionTypeRepresentation::Thick, false, false, false,
                      false, false, SILFunctionTypeIsolation::forUnknown(),
                      DifferentiabilityKind::NonDifferentiable),
-            ClangTypeInfo(nullptr), /*LifetimeDependenceInfo*/ std::nullopt) {}
+            ClangTypeInfo(nullptr), /*LifetimeDependenceInfo*/ {}) {}
 
   SILExtInfoBuilder(Representation rep, bool isPseudogeneric, bool isNoEscape,
                     bool isSendable, bool isAsync, bool isUnimplementable,
@@ -1227,11 +1271,19 @@ class SILExtInfoBuilder {
     return SILExtInfoBuilder(bits, ClangTypeInfo(type).getCanonical(),
                              lifetimeDependencies);
   }
+
+  /// \p lifetimeDependencies should be arena allocated and not a temporary
+  /// Function types are allocated on the are arena and their ExtInfo should be
+  /// valid throughout their lifetime.
   [[nodiscard]] SILExtInfoBuilder withLifetimeDependencies(
       ArrayRef<LifetimeDependenceInfo> lifetimeDependenceInfo) const {
     return SILExtInfoBuilder(bits, clangTypeInfo, lifetimeDependenceInfo);
   }
 
+  [[nodiscard]] ASTExtInfoBuilder withLifetimeDependencies(
+      SmallVectorImpl<LifetimeDependenceInfo> lifetimeDependencies) const =
+      delete;
+
   void Profile(llvm::FoldingSetNodeID &ID) const {
     ID.AddInteger(bits);
     ID.AddPointer(clangTypeInfo.getType());
@@ -1368,11 +1420,17 @@ class SILExtInfo {
     return builder.withUnimplementable(isUnimplementable).build();
   }
 
+  /// \p lifetimeDependencies should be arena allocated and not a temporary
+  /// Function types are allocated on the are arena and their ExtInfo should be
+  /// valid throughout their lifetime.
   SILExtInfo withLifetimeDependencies(
       ArrayRef<LifetimeDependenceInfo> lifetimeDependencies) const {
     return builder.withLifetimeDependencies(lifetimeDependencies);
   }
 
+  SILExtInfo withLifetimeDependencies(SmallVectorImpl<LifetimeDependenceInfo>
+                                          lifetimeDependencies) const = delete;
+
   void Profile(llvm::FoldingSetNodeID &ID) const { builder.Profile(ID); }
 
   bool isEqualTo(SILExtInfo other, bool useClangTypes) const {
diff --git a/include/swift/AST/FeatureAvailability.def b/include/swift/AST/FeatureAvailability.def
index 1321362c5c1b2..71413c18a11d8 100644
--- a/include/swift/AST/FeatureAvailability.def
+++ b/include/swift/AST/FeatureAvailability.def
@@ -82,6 +82,7 @@ FEATURE(ValueGenericType,                               (6, 2))
 FEATURE(InitRawStructMetadata2,                         (6, 2))
 FEATURE(CustomGlobalExecutors,                          (6, 2))
 FEATURE(TaskExecutor,                                   (6, 2))
+FEATURE(TypedCoroAlloc,                                 (6, 2))
 
 FEATURE(Differentiation,                                FUTURE)
 FEATURE(ClearSensitive,                                 FUTURE)
diff --git a/include/swift/AST/FileUnit.h b/include/swift/AST/FileUnit.h
index 512e6b04f00a8..59f93166ac3d4 100644
--- a/include/swift/AST/FileUnit.h
+++ b/include/swift/AST/FileUnit.h
@@ -126,6 +126,13 @@ class FileUnit : public DeclContext, public ASTAllocated<FileUnit> {
                             const ModuleDecl *importedModule,
                             llvm::SmallSetVector<Identifier, 4> &spiGroups) const {};
 
+  /// Returns true if any import of \p importedModule has the `@preconcurrency`
+  /// attribute.
+  virtual bool
+  isModuleImportedPreconcurrency(const ModuleDecl *importedModule) const {
+    return false;
+  };
+
   /// Find all availability domains defined in this module with the given
   /// identifier.
   ///
diff --git a/include/swift/AST/FunctionRefInfo.h b/include/swift/AST/FunctionRefInfo.h
index a298f08e8c274..254179529d930 100644
--- a/include/swift/AST/FunctionRefInfo.h
+++ b/include/swift/AST/FunctionRefInfo.h
@@ -21,6 +21,8 @@
 #include "swift/Basic/Debug.h"
 #include "swift/Basic/LLVM.h"
 
+#include <cstdint>
+
 namespace swift {
 
 class DeclNameLoc;
diff --git a/include/swift/AST/GenericEnvironment.h b/include/swift/AST/GenericEnvironment.h
index 6af9e538a2297..b5578631bb535 100644
--- a/include/swift/AST/GenericEnvironment.h
+++ b/include/swift/AST/GenericEnvironment.h
@@ -61,13 +61,13 @@ struct OpaqueEnvironmentData {
 };
 
 /// Extra data in a generic environment for an opened existential.
-struct OpenedExistentialEnvironmentData {
+struct ExistentialEnvironmentData {
   Type existential;
   UUID uuid;
 };
 
 /// Extra data in a generic environment for an opened pack element.
-struct OpenedElementEnvironmentData {
+struct ElementEnvironmentData {
   UUID uuid;
   CanGenericTypeParamType shapeClass;
 };
@@ -85,37 +85,38 @@ class alignas(1 << DeclAlignInBits) GenericEnvironment final
         GenericEnvironment,
         SubstitutionMap,
         OpaqueEnvironmentData,
-        OpenedExistentialEnvironmentData,
-        OpenedElementEnvironmentData,
+        ExistentialEnvironmentData,
+        ElementEnvironmentData,
         Type> {
 public:
-  enum class Kind {
+  enum class Kind: uint8_t {
     /// A normal generic environment, determined only by its generic
     /// signature.
     Primary,
     /// A generic environment describing an opaque type archetype.
     Opaque,
     /// A generic environment describing an opened existential archetype.
-    OpenedExistential,
+    Existential,
     /// A generic environment describing an opened element type of a
     /// pack archetype inside a pack expansion expression.
-    OpenedElement,
+    Element,
   };
 
   class NestedTypeStorage;
 
 private:
-  mutable llvm::PointerIntPair<GenericSignature, 2, Kind> SignatureAndKind{
-      GenericSignature(), Kind::Primary};
+  GenericSignature sig;
   NestedTypeStorage *nestedTypeStorage = nullptr;
+  Kind kind;
+  bool canonical;
 
   friend TrailingObjects;
   friend OpaqueTypeArchetypeType;
 
   size_t numTrailingObjects(OverloadToken<SubstitutionMap>) const;
   size_t numTrailingObjects(OverloadToken<OpaqueEnvironmentData>) const;
-  size_t numTrailingObjects(OverloadToken<OpenedExistentialEnvironmentData>) const;
-  size_t numTrailingObjects(OverloadToken<OpenedElementEnvironmentData>) const;
+  size_t numTrailingObjects(OverloadToken<ExistentialEnvironmentData>) const;
+  size_t numTrailingObjects(OverloadToken<ElementEnvironmentData>) const;
   size_t numTrailingObjects(OverloadToken<Type>) const;
 
   /// Retrieve the array containing the context types associated with the
@@ -168,10 +169,13 @@ class alignas(1 << DeclAlignInBits) GenericEnvironment final
 
 public:
   GenericSignature getGenericSignature() const {
-    return SignatureAndKind.getPointer();
+    return sig;
   }
 
-  Kind getKind() const { return SignatureAndKind.getInt(); }
+  Kind getKind() const { return kind; }
+
+  /// Returns if the archetypes from this environment are canonical types.
+  bool isCanonical() const { return canonical; }
 
   ArrayRef<GenericTypeParamType *> getGenericParams() const;
 
@@ -325,19 +329,6 @@ class alignas(1 << DeclAlignInBits) GenericEnvironment final
   /// abstraction level of their associated type requirements.
   SILType mapTypeIntoContext(SILModule &M, SILType type) const;
 
-  /// Map an interface type's protocol conformance into the corresponding
-  /// conformance for the contextual type.
-  static std::pair<Type, ProtocolConformanceRef>
-  mapConformanceRefIntoContext(GenericEnvironment *genericEnv,
-                               Type conformingType,
-                               ProtocolConformanceRef conformance);
-
-  /// Map an interface type's protocol conformance into the corresponding
-  /// conformance for the contextual type.
-  std::pair<Type, ProtocolConformanceRef>
-  mapConformanceRefIntoContext(Type conformingType,
-                               ProtocolConformanceRef conformance) const;
-
   /// Returns a substitution map that sends every generic parameter to its
   /// corresponding archetype in this generic environment.
   SubstitutionMap getForwardingSubstitutionMap() const;
diff --git a/include/swift/AST/GenericParamList.h b/include/swift/AST/GenericParamList.h
index fc3ebe33941cf..3c29a0793a453 100644
--- a/include/swift/AST/GenericParamList.h
+++ b/include/swift/AST/GenericParamList.h
@@ -277,11 +277,11 @@ class GenericParamList final :
                                   SourceLoc RAngleLoc);
 
   MutableArrayRef<GenericTypeParamDecl *> getParams() {
-    return {getTrailingObjects<GenericTypeParamDecl *>(), NumParams};
+    return getTrailingObjects(NumParams);
   }
 
   ArrayRef<GenericTypeParamDecl *> getParams() const {
-    return {getTrailingObjects<GenericTypeParamDecl *>(), NumParams};
+    return getTrailingObjects(NumParams);
   }
 
   using iterator = GenericTypeParamDecl **;
@@ -387,12 +387,12 @@ class alignas(RequirementRepr) TrailingWhereClause final :
 
   /// Retrieve the set of requirements.
   MutableArrayRef<RequirementRepr> getRequirements() {
-    return {getTrailingObjects<RequirementRepr>(), NumRequirements};
+    return getTrailingObjects(NumRequirements);
   }
 
   /// Retrieve the set of requirements.
   ArrayRef<RequirementRepr> getRequirements() const {
-    return {getTrailingObjects<RequirementRepr>(), NumRequirements};
+    return getTrailingObjects(NumRequirements);
   }
 
   /// Compute the source range containing this trailing where clause.
diff --git a/include/swift/AST/GenericSignature.h b/include/swift/AST/GenericSignature.h
index cca6904965974..352af26fe472f 100644
--- a/include/swift/AST/GenericSignature.h
+++ b/include/swift/AST/GenericSignature.h
@@ -120,6 +120,10 @@ class GenericSignature {
                               ArrayRef<Requirement> requirements,
                               bool isKnownCanonical = false);
 
+  /// Create a new placeholder generic signature from a set of generic
+  /// parameters. This is necessary for recovery in invalid cases.
+  static GenericSignature forInvalid(ArrayRef<GenericTypeParamType *> params);
+
   /// Produce a new generic signature which drops all of the marker
   /// protocol conformance requirements associated with this one.
   GenericSignature withoutMarkerProtocols() const;
@@ -376,6 +380,19 @@ class alignas(1 << TypeAlignInBits) GenericSignatureImpl final
   /// the given protocol.
   bool requiresProtocol(Type type, ProtocolDecl *proto) const;
 
+  /// Determine whether a conformance requirement of the given type to the
+  /// given protocol prohibits the use of an isolated conformance.
+  ///
+  /// The use of an isolated conformance to satisfy a requirement T: P is
+  /// prohibited when T is a type parameter and T, or some type that can be
+  /// used to reach T, also conforms to Sendable or SendableMetatype. In that
+  /// case, the conforming type and the protocol (Sendable or SendableMetatype)
+  /// is returned.
+  ///
+  /// If there is no such requirement, returns std::nullopt.
+  std::optional<std::pair<Type, ProtocolDecl *>>
+  prohibitsIsolatedConformance(Type type) const;
+
   /// Determine whether the given dependent type is equal to a concrete type.
   bool isConcreteType(Type type) const;
 
@@ -489,8 +506,8 @@ class alignas(1 << TypeAlignInBits) GenericSignatureImpl final
                       ArrayRef<GenericTypeParamType *> genericParams,
                       ArrayRef<Requirement> requirements);
   
-  void print(raw_ostream &OS, PrintOptions Options = PrintOptions()) const;
-  void print(ASTPrinter &Printer, PrintOptions Opts = PrintOptions()) const;
+  void print(raw_ostream &OS, const PrintOptions &Options = PrintOptions()) const;
+  void print(ASTPrinter &Printer, const PrintOptions &Opts = PrintOptions()) const;
   SWIFT_DEBUG_DUMP;
   std::string getAsString() const;
 
@@ -593,7 +610,11 @@ enum class GenericSignatureErrorFlags {
 
   /// The Knuth-Bendix completion procedure failed to construct a confluent
   /// rewrite system.
-  CompletionFailed = (1<<2)
+  CompletionFailed = (1<<2),
+
+  /// A request evaluator cycle prevented us from computing this generic
+  /// signature.
+  CircularReference = (1<<3),
 };
 
 using GenericSignatureErrors = OptionSet<GenericSignatureErrorFlags>;
@@ -604,6 +625,23 @@ using GenericSignatureErrors = OptionSet<GenericSignatureErrorFlags>;
 using GenericSignatureWithError = llvm::PointerIntPair<GenericSignature, 3,
                                                        GenericSignatureErrors>;
 
+/// Build a generic signature from the given requirements, which are not
+/// required to be minimal or canonical, and may contain unresolved
+/// DependentMemberTypes. The generic signature is returned with the
+/// error flags (if any) that were raised while building the signature.
+///
+/// \param baseSignature if non-null, the new parameters and requirements
+///// are added on; existing requirements of the base signature might become
+///// redundant. Otherwise if null, build a new signature from scratch.
+/// \param allowInverses if true, default requirements to Copyable/Escapable are
+/// expanded for generic parameters.
+GenericSignatureWithError buildGenericSignatureWithError(
+    ASTContext &ctx,
+    GenericSignature baseSignature,
+    SmallVector<GenericTypeParamType *, 2> addedParameters,
+    SmallVector<Requirement, 2> addedRequirements,
+    bool allowInverses);
+
 } // end namespace swift
 
 namespace llvm {
diff --git a/include/swift/AST/GenericTypeParamKind.h b/include/swift/AST/GenericTypeParamKind.h
index dff51f1b48e2a..13b5caf3a9e8d 100644
--- a/include/swift/AST/GenericTypeParamKind.h
+++ b/include/swift/AST/GenericTypeParamKind.h
@@ -2,31 +2,38 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2024 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//
-//
-// This file defines the GenericTypeParamKind enum.
-//
+///
+/// This file defines the `GenericTypeParamKind` enum.
+///
 //===----------------------------------------------------------------------===//
 
 #ifndef SWIFT_AST_GENERICTYPEPARAMKIND_H
 #define SWIFT_AST_GENERICTYPEPARAMKIND_H
 
+/// `GenericTypeParamKind.h` is imported into Swift. Be *very* careful with
+/// what you include here and keep these includes minimal!
+///
+/// See include caveats in `BasicBridging.h`.
+#include "swift/Basic/SwiftBridging.h"
+#include <stdint.h>
+
 namespace swift {
 /// Describes the kind of a generic type parameter that occurs within generic
 /// parameter lists.
-enum class GenericTypeParamKind: uint8_t {
+enum class ENUM_EXTENSIBILITY_ATTR(closed) GenericTypeParamKind : uint8_t {
   /// A regular generic type parameter: 'T'
-  Type,
+  Type SWIFT_NAME("type"),
   /// A generic parameter pack: 'each T'
-  Pack,
+  Pack SWIFT_NAME("pack"),
   /// A generic value parameter: 'let T'
-  Value
+  Value SWIFT_NAME("value")
 };
 
 } // namespace swift
diff --git a/include/swift/AST/IRGenOptions.h b/include/swift/AST/IRGenOptions.h
index 21e868a03c52e..eddbc98292bb3 100644
--- a/include/swift/AST/IRGenOptions.h
+++ b/include/swift/AST/IRGenOptions.h
@@ -29,9 +29,9 @@
 #include "llvm/IR/CallingConv.h"
 // FIXME: This include is just for llvm::SanitizerCoverageOptions. We should
 // split the header upstream so we don't include so much.
-#include "llvm/Transforms/Instrumentation.h"
-#include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/VersionTuple.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Utils/Instrumentation.h"
 #include <optional>
 #include <string>
 #include <tuple>
@@ -498,8 +498,6 @@ class IRGenOptions {
   /// Internalize symbols (static library) - do not export any public symbols.
   unsigned InternalizeSymbols : 1;
 
-  unsigned MergeableSymbols : 1;
-
   /// Emit a section with references to class_ro_t* in generic class patterns.
   unsigned EmitGenericRODatas : 1;
 
@@ -566,6 +564,9 @@ class IRGenOptions {
   /// Pointer authentication.
   PointerAuthOptions PointerAuth;
 
+  // If not 0, this overrides the value defined by the target.
+  uint64_t CustomLeastValidPointerValue = 0;
+
   /// The different modes for dumping IRGen type info.
   enum class TypeInfoDumpFilter {
     All,
@@ -604,6 +605,9 @@ class IRGenOptions {
   /// Paths to the pass plugins registered via -load-pass-plugin.
   std::vector<std::string> LLVMPassPlugins;
 
+  /// Set to true if we support AArch64TBI.
+  bool HasAArch64TBI = false;
+
   IRGenOptions()
       : OutputKind(IRGenOutputKind::LLVMAssemblyAfterOptimization),
         Verify(true), VerifyEach(false), OptMode(OptimizationMode::NotSet),
@@ -640,22 +644,20 @@ class IRGenOptions {
         DisableStandardSubstitutionsInReflectionMangling(false),
         EnableGlobalISel(false), VirtualFunctionElimination(false),
         WitnessMethodElimination(false), ConditionalRuntimeRecords(false),
-        AnnotateCondFailMessage(false),
-        InternalizeAtLink(false), InternalizeSymbols(false),
-        MergeableSymbols(false), EmitGenericRODatas(true),
+        AnnotateCondFailMessage(false), InternalizeAtLink(false),
+        InternalizeSymbols(false), EmitGenericRODatas(true),
         NoPreallocatedInstantiationCaches(false),
         DisableReadonlyStaticObjects(false), CollocatedMetadataFunctions(false),
         ColocateTypeDescriptors(true), UseRelativeProtocolWitnessTables(false),
         UseFragileResilientProtocolWitnesses(false), EnableHotColdSplit(false),
-        EmitAsyncFramePushPopMetadata(true), EmitTypeMallocForCoroFrame(false),
+        EmitAsyncFramePushPopMetadata(true), EmitTypeMallocForCoroFrame(true),
         AsyncFramePointerAll(false), UseProfilingMarkerThunks(false),
-        UseCoroCCX8664(false), UseCoroCCArm64(false),
-        MergeableTraps(false),
+        UseCoroCCX8664(false), UseCoroCCArm64(false), MergeableTraps(false),
         DebugInfoForProfiling(false), CmdArgs(),
         SanitizeCoverage(llvm::SanitizerCoverageOptions()),
         TypeInfoFilter(TypeInfoDumpFilter::All),
         PlatformCCallingConvention(llvm::CallingConv::C), UseCASBackend(false),
-        CASObjMode(llvm::CASBackendMode::Native) {
+        CASObjMode(llvm::CASBackendMode::Native), HasAArch64TBI(false) {
     DisableRoundTripDebugTypes = !CONDITIONAL_ASSERT_enabled();
   }
 
diff --git a/include/swift/AST/IRGenRequests.h b/include/swift/AST/IRGenRequests.h
index a9819b2726105..7285a7370f95f 100644
--- a/include/swift/AST/IRGenRequests.h
+++ b/include/swift/AST/IRGenRequests.h
@@ -68,6 +68,7 @@ class GeneratedModule final {
   std::unique_ptr<llvm::LLVMContext> Context;
   std::unique_ptr<llvm::Module> Module;
   std::unique_ptr<llvm::TargetMachine> Target;
+  std::unique_ptr<llvm::raw_fd_ostream> RemarkStream;
 
   GeneratedModule() : Context(nullptr), Module(nullptr), Target(nullptr) {}
 
@@ -81,13 +82,14 @@ class GeneratedModule final {
   /// needed, use \c GeneratedModule::null() instead.
   explicit GeneratedModule(std::unique_ptr<llvm::LLVMContext> &&Context,
                            std::unique_ptr<llvm::Module> &&Module,
-                           std::unique_ptr<llvm::TargetMachine> &&Target)
-    : Context(std::move(Context)), Module(std::move(Module)),
-      Target(std::move(Target)) {
-      assert(getModule() && "Use GeneratedModule::null() instead");
-      assert(getContext() && "Use GeneratedModule::null() instead");
-      assert(getTargetMachine() && "Use GeneratedModule::null() instead");
-    }
+                           std::unique_ptr<llvm::TargetMachine> &&Target,
+                           std::unique_ptr<llvm::raw_fd_ostream> &&RemarkStream)
+      : Context(std::move(Context)), Module(std::move(Module)),
+        Target(std::move(Target)), RemarkStream(std::move(RemarkStream)) {
+    assert(getModule() && "Use GeneratedModule::null() instead");
+    assert(getContext() && "Use GeneratedModule::null() instead");
+    assert(getTargetMachine() && "Use GeneratedModule::null() instead");
+  }
 
   GeneratedModule(GeneratedModule &&) = default;
   GeneratedModule& operator=(GeneratedModule &&) = default;
diff --git a/include/swift/AST/Identifier.h b/include/swift/AST/Identifier.h
index 036685873da73..68ee30595bc77 100644
--- a/include/swift/AST/Identifier.h
+++ b/include/swift/AST/Identifier.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -17,6 +17,19 @@
 #ifndef SWIFT_AST_IDENTIFIER_H
 #define SWIFT_AST_IDENTIFIER_H
 
+/// `Identifier.h` is imported into Swift. Be *very* careful with what you
+/// include here and keep these includes minimal!
+/// If you don't need to import a header into Swift, include it in the `#ifdef`
+/// block below instead.
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
+#include "swift/Basic/SwiftBridging.h"
+#include <assert.h>
+#include <stdint.h>
+
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
 #include "swift/Basic/EditorPlaceholder.h"
 #include "swift/Basic/Debug.h"
 #include "swift/Basic/LLVM.h"
@@ -25,6 +38,10 @@
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/Support/TrailingObjects.h"
 
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
+SWIFT_BEGIN_NULLABILITY_ANNOTATIONS
+
 namespace llvm {
   class raw_ostream;
 }
@@ -56,8 +73,8 @@ class Identifier {
   friend class ASTContext;
   friend class DeclBaseName;
 
-  const char *Pointer;
-  
+  const char *_Nullable Pointer;
+
 public:
   enum : size_t {
     NumLowBitsAvailable = 3,
@@ -67,7 +84,7 @@ class Identifier {
 
 private:
   /// Constructor, only accessible by ASTContext, which handles the uniquing.
-  explicit Identifier(const char *Ptr) : Pointer(Ptr) {
+  explicit Identifier(const char *_Nullable Ptr) : Pointer(Ptr) {
     assert(((uintptr_t)Ptr & SpareBitMask) == 0
            && "Identifier pointer does not use any spare bits");
   }
@@ -80,25 +97,35 @@ class Identifier {
 
 public:
   explicit Identifier() : Pointer(nullptr) {}
-  
-  const char *get() const { return Pointer; }
-  
-  StringRef str() const { return Pointer; }
 
-  explicit operator std::string() const { return std::string(Pointer); }
+  SWIFT_UNAVAILABLE("Use 'init(raw:)' instead")
+  static Identifier getFromOpaquePointer(const void *_Nullable P) {
+    return Identifier((const char *)P);
+  }
+#ifdef COMPILED_WITH_SWIFT
+  SWIFT_NAME("init(raw:)")
+  Identifier(const void *_Nullable raw) : Pointer((const char *)raw) {}
+#endif
 
-  unsigned getLength() const {
-    assert(Pointer != nullptr && "Tried getting length of empty identifier");
-    return ::strlen(Pointer);
+  SWIFT_UNAVAILABLE("Use 'raw' instead")
+  const void *_Nullable getAsOpaquePointer() const {
+    return static_cast<const void *>(Pointer);
   }
-  
+#ifdef COMPILED_WITH_SWIFT
+  SWIFT_COMPUTED_PROPERTY
+  SWIFT_IMPORT_UNSAFE
+  const void *_Nullable getRaw() const { return getAsOpaquePointer(); }
+#endif
+
+  SWIFT_UNAVAILABLE("Use 'isValid' instead")
   bool empty() const { return Pointer == nullptr; }
+  SWIFT_UNAVAILABLE("Use 'isValid' instead")
   bool nonempty() const { return !empty(); }
+#ifdef COMPILED_WITH_SWIFT
+  SWIFT_COMPUTED_PROPERTY
+  bool getIsValid() const { return nonempty(); }
+#endif
 
-  LLVM_ATTRIBUTE_USED bool is(StringRef string) const {
-    return str() == string;
-  }
-  
   /// isOperator - Return true if this identifier is an operator, false if it is
   /// a normal identifier.
   bool isOperator() const {
@@ -111,6 +138,23 @@ class Identifier {
     return isOperatorSlow();
   }
 
+  SWIFT_UNAVAILABLE("Unavailable in Swift")
+  bool isEditorPlaceholder() const;
+
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
+  const char *_Nullable get() const { return Pointer; }
+
+  unsigned getLength() const {
+    assert(Pointer != nullptr && "Tried getting length of empty identifier");
+    return ::strlen(Pointer);
+  }
+
+  static bool isEditorPlaceholder(StringRef name) {
+    return swift::isEditorPlaceholder(name);
+  }
+
   /// Returns true if this identifier contains non-identifier characters and
   /// must always be escaped with backticks, even in contexts were other
   /// escaped identifiers could omit backticks (like keywords as argument
@@ -140,6 +184,10 @@ class Identifier {
     return is("??");
   }
 
+  // Returns whether this is a standard infix logical operator,
+  // such as '&&', '||'.
+  bool isStandardInfixLogicalOperator() const { return is("&&") || is("||"); }
+
   /// isOperatorStartCodePoint - Return true if the specified code point is a
   /// valid start of an operator.
   static bool isOperatorStartCodePoint(uint32_t C) {
@@ -176,13 +224,7 @@ class Identifier {
         || (C >= 0xE0100 && C <= 0xE01EF);
   }
 
-  static bool isEditorPlaceholder(StringRef name) {
-    return swift::isEditorPlaceholder(name);
-  }
-
-  bool isEditorPlaceholder() const {
-    return !empty() && isEditorPlaceholder(str());
-  }
+  StringRef str() const { return Pointer; }
 
   bool hasDollarPrefix() const {
     return str().starts_with("$") && !(getLength() == 1);
@@ -191,13 +233,9 @@ class Identifier {
   bool hasUnderscoredNaming() const {
     return str().starts_with("_");
   }
-  
-  const void *getAsOpaquePointer() const {
-      return static_cast<const void *>(Pointer);
-  }
-  
-  static Identifier getFromOpaquePointer(const void *P) {
-    return Identifier((const char*)P);
+
+  LLVM_ATTRIBUTE_USED bool is(StringRef string) const {
+    return str() == string;
   }
 
   /// Compare two identifiers, producing -1 if \c *this comes before \c other,
@@ -206,6 +244,8 @@ class Identifier {
   /// Null identifiers come after all other identifiers.
   int compare(Identifier other) const;
 
+  explicit operator std::string() const { return std::string(Pointer); }
+
   friend llvm::hash_code hash_value(Identifier ident) {
     return llvm::hash_value(ident.getAsOpaquePointer());
   }
@@ -227,16 +267,21 @@ class Identifier {
     return Identifier((const char*)Val);
   }
 
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
 private:
   bool isOperatorSlow() const;
 };
-  
+
 class DeclName;
 class DeclNameRef;
 class ObjCSelector;
 
 } // end namespace swift
 
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
 namespace llvm {
   raw_ostream &operator<<(raw_ostream &OS, swift::Identifier I);
   raw_ostream &operator<<(raw_ostream &OS, swift::DeclName I);
@@ -264,10 +309,10 @@ namespace llvm {
   template<>
   struct PointerLikeTypeTraits<swift::Identifier> {
   public:
-    static inline void *getAsVoidPointer(swift::Identifier I) {
+    static inline void *_Nullable getAsVoidPointer(swift::Identifier I) {
       return const_cast<void *>(I.getAsOpaquePointer());
     }
-    static inline swift::Identifier getFromVoidPointer(void *P) {
+    static inline swift::Identifier getFromVoidPointer(void *_Nullable P) {
       return swift::Identifier::getFromOpaquePointer(P);
     }
     enum { NumLowBitsAvailable = swift::Identifier::NumLowBitsAvailable };
@@ -275,15 +320,13 @@ namespace llvm {
   
 } // end namespace llvm
 
-class BridgedDeclBaseName;
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 
 namespace swift {
 
 /// Wrapper that may either be an Identifier or a special name
 /// (e.g. for subscripts)
 class DeclBaseName {
-  friend class ::BridgedDeclBaseName;
-
 public:
   enum class Kind: uint8_t {
     Normal,
@@ -322,6 +365,9 @@ class DeclBaseName {
     return DeclBaseName(Identifier((const char *)&DestructorIdentifierData));
   }
 
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
   Kind getKind() const {
     if (Ident.get() == (const char *)&SubscriptIdentifierData) {
       return Kind::Subscript;
@@ -362,7 +408,7 @@ class DeclBaseName {
   }
 
   bool hasDollarPrefix() const {
-    return getIdentifier().hasDollarPrefix();
+    return !isSpecial() && getIdentifier().hasDollarPrefix();
   }
 
   /// A representation of the name to be displayed to users. May be ambiguous
@@ -404,15 +450,20 @@ class DeclBaseName {
     return Ident.get() < RHS.Ident.get();
   }
 
-  const void *getAsOpaquePointer() const { return Ident.get(); }
+  const void *_Nullable getAsOpaquePointer() const { return Ident.get(); }
 
-  static DeclBaseName getFromOpaquePointer(void *P) {
+  static DeclBaseName getFromOpaquePointer(void *_Nullable P) {
     return Identifier::getFromOpaquePointer(P);
   }
+
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 };
 
 } // end namespace swift
 
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
 namespace llvm {
 
 raw_ostream &operator<<(raw_ostream &OS, swift::DeclBaseName D);
@@ -437,10 +488,10 @@ template<> struct DenseMapInfo<swift::DeclBaseName> {
 template <typename T> struct PointerLikeTypeTraits;
 template <> struct PointerLikeTypeTraits<swift::DeclBaseName> {
 public:
-  static inline void *getAsVoidPointer(swift::DeclBaseName D) {
+  static inline void *_Nullable getAsVoidPointer(swift::DeclBaseName D) {
     return const_cast<void *>(D.getAsOpaquePointer());
   }
-  static inline swift::DeclBaseName getFromVoidPointer(void *P) {
+  static inline swift::DeclBaseName getFromVoidPointer(void *_Nullable P) {
     return swift::DeclBaseName::getFromOpaquePointer(P);
   }
   enum { NumLowBitsAvailable = PointerLikeTypeTraits<swift::Identifier>::NumLowBitsAvailable };
@@ -467,10 +518,10 @@ class DeclName {
         : BaseName(BaseName), NumArgs(NumArgs) { }
     
     ArrayRef<Identifier> getArgumentNames() const {
-      return {getTrailingObjects<Identifier>(), NumArgs};
+      return getTrailingObjects(NumArgs);
     }
     MutableArrayRef<Identifier> getArgumentNames() {
-      return {getTrailingObjects<Identifier>(), NumArgs};
+      return getTrailingObjects(NumArgs);
     }
 
     /// Uniquing for the ASTContext.
@@ -486,9 +537,9 @@ class DeclName {
   /// compound declaration name.
   llvm::PointerUnion<DeclBaseName, CompoundDeclName *> BaseNameOrCompound;
 
-  explicit DeclName(void *Opaque)
-    : BaseNameOrCompound(decltype(BaseNameOrCompound)::getFromOpaqueValue(Opaque))
-  {}
+  explicit DeclName(void *_Nullable Opaque)
+      : BaseNameOrCompound(
+            decltype(BaseNameOrCompound)::getFromOpaqueValue(Opaque)) {}
 
   void initialize(ASTContext &C, DeclBaseName baseName,
                   ArrayRef<Identifier> argumentNames);
@@ -512,7 +563,8 @@ class DeclName {
 
   /// Build a compound value name given a base name and a set of argument names
   /// extracted from a parameter list.
-  DeclName(ASTContext &C, DeclBaseName baseName, ParameterList *paramList);
+  DeclName(ASTContext &C, DeclBaseName baseName,
+           ParameterList *_Nonnull paramList);
 
   /// Retrieve the 'base' name, i.e., the name that follows the introducer,
   /// such as the 'foo' in 'func foo(x:Int, y:Int)' or the 'bar' in
@@ -521,7 +573,7 @@ class DeclName {
     if (auto compound = BaseNameOrCompound.dyn_cast<CompoundDeclName*>())
       return compound->BaseName;
 
-    return BaseNameOrCompound.get<DeclBaseName>();
+    return cast<DeclBaseName>(BaseNameOrCompound);
   }
 
   /// Assert that the base name is not special and return its identifier.
@@ -545,13 +597,11 @@ class DeclName {
   explicit operator bool() const {
     if (BaseNameOrCompound.dyn_cast<CompoundDeclName*>())
       return true;
-    return !BaseNameOrCompound.get<DeclBaseName>().empty();
+    return !cast<DeclBaseName>(BaseNameOrCompound).empty();
   }
   
   /// True if this is a simple one-component name.
-  bool isSimpleName() const {
-    return BaseNameOrCompound.is<DeclBaseName>();
-  }
+  bool isSimpleName() const { return isa<DeclBaseName>(BaseNameOrCompound); }
 
   /// True if this is a compound name.
   bool isCompoundName() const {
@@ -649,8 +699,10 @@ class DeclName {
     return lhs.compare(rhs) >= 0;
   }
 
-  void *getOpaqueValue() const { return BaseNameOrCompound.getOpaqueValue(); }
-  static DeclName getFromOpaqueValue(void *p) { return DeclName(p); }
+  void *_Nullable getOpaqueValue() const {
+    return BaseNameOrCompound.getOpaqueValue();
+  }
+  static DeclName getFromOpaqueValue(void *_Nullable p) { return DeclName(p); }
 
   /// Get a string representation of the name,
   ///
@@ -663,8 +715,12 @@ class DeclName {
   ///
   /// \param skipEmptyArgumentNames When true, don't print the argument labels
   /// if they are all empty.
+  ///
+  /// \param escapeIfNeeded When true, escape identifiers with backticks
+  /// when required.
   llvm::raw_ostream &print(llvm::raw_ostream &os,
-                           bool skipEmptyArgumentNames = false) const;
+                           bool skipEmptyArgumentNames = false,
+                           bool escapeIfNeeded = false) const;
 
   /// Print a "pretty" representation of this declaration name to the given
   /// stream.
@@ -690,68 +746,76 @@ class DeclNameRef {
 
   DeclNameRef() : FullName() { }
 
-  void *getOpaqueValue() const { return FullName.getOpaqueValue(); }
-  static DeclNameRef getFromOpaqueValue(void *p);
+  void *_Nullable getOpaqueValue() const { return FullName.getOpaqueValue(); }
+  static DeclNameRef getFromOpaqueValue(void *_Nullable p);
+
+  explicit DeclNameRef(ASTContext &C, Identifier moduleSelector,
+                       DeclName fullName)
+    : FullName(fullName) { }
+
+  explicit DeclNameRef(ASTContext &C, Identifier moduleSelector,
+                       DeclBaseName baseName, ArrayRef<Identifier> argLabels)
+    : FullName(C, baseName, argLabels) { }
 
   explicit DeclNameRef(DeclName FullName)
     : FullName(FullName) { }
 
-  explicit DeclNameRef(DeclBaseName BaseName)
-    : FullName(BaseName) { }
+  bool hasModuleSelector() const {
+    return false;
+  }
 
-  explicit DeclNameRef(Identifier BaseName)
-    : FullName(BaseName) { }
+  Identifier getModuleSelector() const {
+    return Identifier();
+  }
 
   /// The name of the declaration being referenced.
   DeclName getFullName() const {
     return FullName;
   }
 
-  DeclName &getFullName() {
-    return FullName;
-  }
-
   /// The base name of the declaration being referenced.
   DeclBaseName getBaseName() const {
-    return FullName.getBaseName();
+    return getFullName().getBaseName();
   }
 
   Identifier getBaseIdentifier() const {
-    return FullName.getBaseIdentifier();
+    return getFullName().getBaseIdentifier();
   }
 
   ArrayRef<Identifier> getArgumentNames() const {
-    return FullName.getArgumentNames();
+    return getFullName().getArgumentNames();
   }
 
   bool isSimpleName() const {
-    return FullName.isSimpleName();
+    return getFullName().isSimpleName();
   }
 
   bool isSimpleName(DeclBaseName name) const {
-    return FullName.isSimpleName(name);
+    return getFullName().isSimpleName(name);
   }
 
   bool isSimpleName(StringRef name) const {
-    return FullName.isSimpleName(name);
+    return getFullName().isSimpleName(name);
   }
 
   bool isSpecial() const {
-    return FullName.isSpecial();
+    return getFullName().isSpecial();
   }
 
   bool isOperator() const {
-    return FullName.isOperator();
+    return getFullName().isOperator();
   }
 
-  bool mustAlwaysBeEscaped() const { return FullName.mustAlwaysBeEscaped(); }
+  bool mustAlwaysBeEscaped() const {
+    return getFullName().mustAlwaysBeEscaped();
+  }
 
   bool isCompoundName() const {
-    return FullName.isCompoundName();
+    return getFullName().isCompoundName();
   }
 
   explicit operator bool() const {
-    return (bool)FullName;
+    return (bool)getFullName();
   }
 
   /// Compare two declaration names, producing -1 if \c *this comes before
@@ -791,7 +855,7 @@ class DeclNameRef {
     return lhs.compare(rhs) >= 0;
   }
 
-  DeclNameRef withoutArgumentLabels() const;
+  DeclNameRef withoutArgumentLabels(ASTContext &C) const;
   DeclNameRef withArgumentLabels(ASTContext &C,
                                  ArrayRef<Identifier> argumentNames) const;
 
@@ -820,20 +884,19 @@ class DeclNameRef {
   SWIFT_DEBUG_DUMP;
 };
 
-inline DeclNameRef DeclNameRef::getFromOpaqueValue(void *p) {
+inline DeclNameRef DeclNameRef::getFromOpaqueValue(void *_Nullable p) {
   return DeclNameRef(DeclName::getFromOpaqueValue(p));
 }
 
-inline DeclNameRef DeclNameRef::withoutArgumentLabels() const {
-  return DeclNameRef(getBaseName());
+inline DeclNameRef DeclNameRef::withoutArgumentLabels(ASTContext &C) const {
+  return DeclNameRef(C, getModuleSelector(), getBaseName());
 }
 
 inline DeclNameRef DeclNameRef::withArgumentLabels(
     ASTContext &C, ArrayRef<Identifier> argumentNames) const {
-  return DeclNameRef(DeclName(C, getBaseName(), argumentNames));
+  return DeclNameRef(C, getModuleSelector(), getBaseName(), argumentNames);
 }
 
-
 inline DeclNameRef DeclNameRef::createSubscript() {
   return DeclNameRef(DeclBaseName::createSubscript());
 }
@@ -923,8 +986,8 @@ class ObjCSelector {
 
   ObjCSelectorFamily getSelectorFamily() const;
 
-  void *getOpaqueValue() const { return Storage.getOpaqueValue(); }
-  static ObjCSelector getFromOpaqueValue(void *p) {
+  void *_Nullable getOpaqueValue() const { return Storage.getOpaqueValue(); }
+  static ObjCSelector getFromOpaqueValue(void *_Nullable p) {
     return ObjCSelector(DeclName::getFromOpaqueValue(p));
   }
 
@@ -970,10 +1033,10 @@ namespace llvm {
   template<>
   struct PointerLikeTypeTraits<swift::DeclName> {
   public:
-    static inline void *getAsVoidPointer(swift::DeclName name) {
+    static inline void *_Nullable getAsVoidPointer(swift::DeclName name) {
       return name.getOpaqueValue();
     }
-    static inline swift::DeclName getFromVoidPointer(void *ptr) {
+    static inline swift::DeclName getFromVoidPointer(void *_Nullable ptr) {
       return swift::DeclName::getFromOpaqueValue(ptr);
     }
     enum { NumLowBitsAvailable = PointerLikeTypeTraits<swift::DeclBaseName>::NumLowBitsAvailable - 1 };
@@ -1000,10 +1063,10 @@ namespace llvm {
   template<>
   struct PointerLikeTypeTraits<swift::DeclNameRef> {
   public:
-    static inline void *getAsVoidPointer(swift::DeclNameRef name) {
+    static inline void *_Nullable getAsVoidPointer(swift::DeclNameRef name) {
       return name.getOpaqueValue();
     }
-    static inline swift::DeclNameRef getFromVoidPointer(void *ptr) {
+    static inline swift::DeclNameRef getFromVoidPointer(void *_Nullable ptr) {
       return swift::DeclNameRef::getFromOpaqueValue(ptr);
     }
     enum { NumLowBitsAvailable = PointerLikeTypeTraits<swift::DeclName>::NumLowBitsAvailable };
@@ -1031,10 +1094,10 @@ namespace llvm {
   template<>
   struct PointerLikeTypeTraits<swift::ObjCSelector> {
   public:
-    static inline void *getAsVoidPointer(swift::ObjCSelector name) {
+    static inline void *_Nullable getAsVoidPointer(swift::ObjCSelector name) {
       return name.getOpaqueValue();
     }
-    static inline swift::ObjCSelector getFromVoidPointer(void *ptr) {
+    static inline swift::ObjCSelector getFromVoidPointer(void *_Nullable ptr) {
       return swift::ObjCSelector::getFromOpaqueValue(ptr);
     }
     enum { NumLowBitsAvailable = 0 };
@@ -1058,4 +1121,8 @@ namespace llvm {
   };
 } // end namespace llvm
 
-#endif
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
+SWIFT_END_NULLABILITY_ANNOTATIONS
+
+#endif // #ifndef SWIFT_AST_IDENTIFIER_H
diff --git a/include/swift/AST/Import.h b/include/swift/AST/Import.h
index 0e014d5e24036..7d1f0d89c7c3b 100644
--- a/include/swift/AST/Import.h
+++ b/include/swift/AST/Import.h
@@ -457,6 +457,20 @@ class ImportPath : public detail::ImportPathBase<ImportPath> {
   Access getAccessPath(ImportKind importKind) const {
     return getAccessPath(isScopedImportKind(importKind));
   }
+
+private:
+  struct UnsafePrivateConstructorTag {};
+
+  // Doesn't require a module name like the public constructor.
+  // Only used for getEmptyKey() and getTombstoneKey().
+  ImportPath(Raw raw, UnsafePrivateConstructorTag tag) : ImportPathBase(raw) {}
+public:
+  static ImportPath getEmptyKey() {
+    return swift::ImportPath(llvm::DenseMapInfo<Raw>::getEmptyKey(), UnsafePrivateConstructorTag{});
+  }
+  static ImportPath getTombstoneKey() {
+    return swift::ImportPath(llvm::DenseMapInfo<Raw>::getTombstoneKey(), UnsafePrivateConstructorTag{});
+  }
 };
 
 // MARK: - Abstractions of imports
@@ -810,6 +824,27 @@ struct DenseMapInfo<swift::AttributedImport<ModuleInfo>> {
            a.accessLevelRange == b.accessLevelRange;
   }
 };
+
+template <>
+class DenseMapInfo<swift::ImportPath> {
+  using ImportPath = swift::ImportPath;
+public:
+  static ImportPath getEmptyKey() {
+    return swift::ImportPath::getEmptyKey();
+  }
+  static ImportPath getTombstoneKey() {
+    return swift::ImportPath::getTombstoneKey();
+  }
+
+  static unsigned getHashValue(const ImportPath &val) {
+    return llvm::DenseMapInfo<ImportPath::Raw>::getHashValue(val.getRaw());
+  }
+
+  static bool isEqual(const ImportPath &lhs,
+                      const ImportPath &rhs) {
+    return lhs == rhs;
+  }
+};
 }
 
 #endif
diff --git a/include/swift/AST/ImportCache.h b/include/swift/AST/ImportCache.h
index 7c573d94b5ef8..8c9059f14d5fe 100644
--- a/include/swift/AST/ImportCache.h
+++ b/include/swift/AST/ImportCache.h
@@ -87,25 +87,20 @@ class ImportSet final :
   }
 
   ArrayRef<ImportedModule> getTopLevelImports() const {
-    return {getTrailingObjects<ImportedModule>(),
-            NumTopLevelImports};
+    return getTrailingObjects(NumTopLevelImports);
   }
 
   ArrayRef<ImportedModule> getTransitiveImports() const {
-    return {getTrailingObjects<ImportedModule>() +
-              NumTopLevelImports,
-            NumTransitiveImports};
+    return {getTrailingObjects() + NumTopLevelImports, NumTransitiveImports};
   }
 
   ArrayRef<ImportedModule> getTransitiveSwiftOnlyImports() const {
-    return {getTrailingObjects<ImportedModule>() +
-              NumTopLevelImports + NumTransitiveImports,
+    return {getTrailingObjects() + NumTopLevelImports + NumTransitiveImports,
             NumTransitiveSwiftOnlyImports};
   }
 
   ArrayRef<ImportedModule> getAllImports() const {
-      return {getTrailingObjects<ImportedModule>(),
-              NumTopLevelImports + NumTransitiveImports};
+    return getTrailingObjects(NumTopLevelImports + NumTransitiveImports);
   }
 
   SWIFT_DEBUG_DUMP;
diff --git a/include/swift/AST/InFlightSubstitution.h b/include/swift/AST/InFlightSubstitution.h
index f4188366f6f62..e4bd9cc0b1104 100644
--- a/include/swift/AST/InFlightSubstitution.h
+++ b/include/swift/AST/InFlightSubstitution.h
@@ -23,21 +23,36 @@
 #define SWIFT_AST_INFLIGHTSUBSTITUTION_H
 
 #include "swift/AST/SubstitutionMap.h"
+#include "llvm/ADT/DenseMap.h"
 
 namespace swift {
 class SubstitutionMap;
 
 class InFlightSubstitution {
-  SubstOptions Options;
+  friend class SubstitutionMap;
+
   TypeSubstitutionFn BaselineSubstType;
   LookupConformanceFn BaselineLookupConformance;
+  SubstOptions Options;
   RecursiveTypeProperties Props;
+  unsigned RemainingCount : 31;
+  unsigned InitLimit : 1;
+  unsigned RemainingDepth : 31;
+  unsigned LimitReached : 1;
 
   struct ActivePackExpansion {
     bool isSubstExpansion = false;
     unsigned expansionIndex = 0;
   };
-  SmallVector<ActivePackExpansion, 4> ActivePackExpansions;
+  llvm::SmallVector<ActivePackExpansion, 4> ActivePackExpansions;
+  llvm::SmallDenseMap<SubstitutionMap, SubstitutionMap, 2> SubMaps;
+
+  Type projectLaneFromPackType(
+      Type substType, unsigned level);
+  ProtocolConformanceRef projectLaneFromPackConformance(
+      PackConformance *substPackConf, unsigned level);
+
+  bool checkLimits(Type ty);
 
 public:
   InFlightSubstitution(TypeSubstitutionFn substType,
@@ -52,8 +67,7 @@ class InFlightSubstitution {
   Type substType(SubstitutableType *origType, unsigned level);
 
   /// Perform primitive conformance lookup on the given type.
-  ProtocolConformanceRef lookupConformance(CanType dependentType,
-                                           Type conformingReplacementType,
+  ProtocolConformanceRef lookupConformance(Type dependentType,
                                            ProtocolDecl *conformedProtocol,
                                            unsigned level);
 
@@ -146,6 +160,10 @@ class InFlightSubstitution {
 
   /// Is the given type invariant to substitution?
   bool isInvariant(Type type) const;
+
+  bool wasLimitReached() const {
+    return LimitReached;
+  }
 };
 
 /// A helper classes that provides stable storage for the query
diff --git a/include/swift/AST/KnownIdentifiers.def b/include/swift/AST/KnownIdentifiers.def
index 73e3b44485598..02ef359f568e3 100644
--- a/include/swift/AST/KnownIdentifiers.def
+++ b/include/swift/AST/KnownIdentifiers.def
@@ -29,11 +29,13 @@ IDENTIFIER(alloc)
 IDENTIFIER(allocWithZone)
 IDENTIFIER(allZeros)
 IDENTIFIER(accumulated)
+IDENTIFIER(append)
 IDENTIFIER(ActorType)
 IDENTIFIER(Any)
 IDENTIFIER(ArrayLiteralElement)
 IDENTIFIER(asLocalActor)
 IDENTIFIER(atIndexedSubscript)
+IDENTIFIER(basic_string)
 IDENTIFIER_(bridgeToObjectiveC)
 IDENTIFIER(buildArray)
 IDENTIFIER(buildBlock)
@@ -127,6 +129,7 @@ IDENTIFIER(main)
 IDENTIFIER_WITH_NAME(MainEntryPoint, "$main")
 IDENTIFIER(message)
 IDENTIFIER(next)
+IDENTIFIER(nonsending)
 IDENTIFIER_(nsErrorDomain)
 IDENTIFIER(objectAtIndexedSubscript)
 IDENTIFIER(objectForKeyedSubscript)
@@ -168,6 +171,7 @@ IDENTIFIER(value)
 IDENTIFIER_WITH_NAME(value_, "_value")
 IDENTIFIER(Void)
 IDENTIFIER(WinSDK)
+IDENTIFIER(warn)
 IDENTIFIER(with)
 IDENTIFIER(withArguments)
 IDENTIFIER(withKeywordArguments)
@@ -324,6 +328,7 @@ IDENTIFIER(SerializationRequirement)
 IDENTIFIER_WITH_NAME(builderSelf, "$builderSelf")
 
 // Attribute options
+IDENTIFIER(always)
 IDENTIFIER_(_always)
 IDENTIFIER_(assumed)
 IDENTIFIER(checked)
diff --git a/include/swift/AST/KnownProtocols.h b/include/swift/AST/KnownProtocols.h
index df8247325b7ae..09b1f03be2ffd 100644
--- a/include/swift/AST/KnownProtocols.h
+++ b/include/swift/AST/KnownProtocols.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -14,6 +14,7 @@
 #define SWIFT_AST_KNOWNPROTOCOLS_H
 
 #include "swift/ABI/InvertibleProtocols.h"
+#include "swift/Basic/InlineBitfield.h"
 #include "swift/Config.h"
 
 namespace llvm {
diff --git a/include/swift/AST/KnownStdlibTypes.def b/include/swift/AST/KnownStdlibTypes.def
index fda6ed7b37439..77b9d5b84e463 100644
--- a/include/swift/AST/KnownStdlibTypes.def
+++ b/include/swift/AST/KnownStdlibTypes.def
@@ -70,6 +70,7 @@ KNOWN_STDLIB_TYPE_DECL(WritableKeyPath, NominalTypeDecl, 2)
 KNOWN_STDLIB_TYPE_DECL(ReferenceWritableKeyPath, NominalTypeDecl, 2)
 
 KNOWN_STDLIB_TYPE_DECL(Optional, EnumDecl, 1)
+KNOWN_STDLIB_TYPE_DECL(_OptionalNilComparisonType, NominalTypeDecl, 0)
 
 KNOWN_STDLIB_TYPE_DECL(OptionSet, NominalTypeDecl, 1)
 
@@ -101,6 +102,6 @@ KNOWN_STDLIB_TYPE_DECL(Result, NominalTypeDecl, 2)
 
 KNOWN_STDLIB_TYPE_DECL(InlineArray, NominalTypeDecl, 2)
 
-KNOWN_STDLIB_TYPE_DECL(SwiftSetting, NominalTypeDecl, 0)
+KNOWN_STDLIB_TYPE_DECL(MutableSpan, NominalTypeDecl, 1)
 
 #undef KNOWN_STDLIB_TYPE_DECL
diff --git a/include/swift/AST/LayoutConstraintKind.h b/include/swift/AST/LayoutConstraintKind.h
index 8eeb9fb0796fa..f2bfe10516f78 100644
--- a/include/swift/AST/LayoutConstraintKind.h
+++ b/include/swift/AST/LayoutConstraintKind.h
@@ -2,48 +2,49 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//
-//
-// This file defines types and APIs for layout constraints.
-//
-//===----------------------------------------------------------------------===//
-
-#include <cstdint>
 
 #ifndef SWIFT_LAYOUT_CONSTRAINTKIND_H
 #define SWIFT_LAYOUT_CONSTRAINTKIND_H
 
+/// `LayoutConstraintKind.h` is imported into Swift. Be *very* careful with
+/// what you include here and keep these includes minimal!
+///
+/// See include caveats in `BasicBridging.h`.
+#include "swift/Basic/SwiftBridging.h"
+#include <stdint.h>
+
 namespace swift {
 /// Describes a layout constraint information.
-enum class LayoutConstraintKind : uint8_t {
+enum class ENUM_EXTENSIBILITY_ATTR(closed) LayoutConstraintKind : uint8_t {
   // It is not a known layout constraint.
-  UnknownLayout,
+  UnknownLayout SWIFT_NAME("unknownLayout"),
   // It is a layout constraint representing a trivial type of a known size.
-  TrivialOfExactSize,
+  TrivialOfExactSize SWIFT_NAME("trivialOfExactSize"),
   // It is a layout constraint representing a trivial type of a size known to
   // be no larger than a given size.
-  TrivialOfAtMostSize,
+  TrivialOfAtMostSize SWIFT_NAME("trivialOfAtMostSize"),
   // It is a layout constraint representing a trivial type of an unknown size.
-  Trivial,
+  Trivial SWIFT_NAME("trivial"),
   // It is a layout constraint representing a reference counted class instance.
-  Class,
+  Class SWIFT_NAME("class"),
   // It is a layout constraint representing a reference counted native class
   // instance.
-  NativeClass,
+  NativeClass SWIFT_NAME("nativeClass"),
   // It is a layout constraint representing a reference counted object.
-  RefCountedObject,
+  RefCountedObject SWIFT_NAME("refCountedObject"),
   // It is a layout constraint representing a native reference counted object.
-  NativeRefCountedObject,
+  NativeRefCountedObject SWIFT_NAME("nativeRefCountedObject"),
   // It is a layout constraint representing a bridge object
-  BridgeObject,
+  BridgeObject SWIFT_NAME("bridgeObject"),
   // It is a layout constraint representing a trivial type of a known stride.
-  TrivialStride,
+  TrivialStride SWIFT_NAME("trivialStride"),
   LastLayout = TrivialStride,
 };
 } // namespace swift
diff --git a/include/swift/AST/LazyResolver.h b/include/swift/AST/LazyResolver.h
index 074ed8cc74665..1db9f2fd947b9 100644
--- a/include/swift/AST/LazyResolver.h
+++ b/include/swift/AST/LazyResolver.h
@@ -136,7 +136,7 @@ class alignas(void*) LazyMemberLoader {
                                   uint64_t contextData) = 0;
 
   // Returns the target parameter of the `@_specialize` attribute or null.
-  virtual ValueDecl *loadTargetFunctionDecl(const SpecializeAttr *attr,
+  virtual ValueDecl *loadTargetFunctionDecl(const AbstractSpecializeAttr *attr,
                                             uint64_t contextData) = 0;
 };
 
diff --git a/include/swift/AST/LifetimeDependence.h b/include/swift/AST/LifetimeDependence.h
index 0d8cd14029bbb..7b501920d6cc0 100644
--- a/include/swift/AST/LifetimeDependence.h
+++ b/include/swift/AST/LifetimeDependence.h
@@ -38,8 +38,9 @@ class SILResultInfo;
 
 enum class ParsedLifetimeDependenceKind : uint8_t {
   Default = 0,
-  Scope,
-  Inherit // Only used with deserialized decls
+  Borrow,
+  Inherit, // Only used with deserialized decls
+  Inout
 };
 
 enum class LifetimeDependenceKind : uint8_t { Inherit = 0, Scope };
@@ -140,17 +141,7 @@ struct LifetimeDescriptor {
     return getName().str() == "immortal";
   }
 
-  std::string getString() const {
-    switch (kind) {
-    case DescriptorKind::Named:
-      return getName().str().str();
-    case DescriptorKind::Ordered:
-      return std::to_string(getIndex());
-    case DescriptorKind::Self:
-      return "self";
-    }
-    llvm_unreachable("Invalid DescriptorKind");
-  }
+  std::string getString() const;
 };
 
 class LifetimeEntry final
@@ -169,7 +160,7 @@ class LifetimeEntry final
       : startLoc(startLoc), endLoc(endLoc), numSources(sources.size()),
         targetDescriptor(targetDescriptor) {
     std::uninitialized_copy(sources.begin(), sources.end(),
-                            getTrailingObjects<LifetimeDescriptor>());
+                            getTrailingObjects());
   }
 
   size_t numTrailingObjects(OverloadToken<LifetimeDescriptor>) const {
@@ -182,46 +173,18 @@ class LifetimeEntry final
          ArrayRef<LifetimeDescriptor> sources,
          std::optional<LifetimeDescriptor> targetDescriptor = std::nullopt);
 
+  std::string getString() const;
   SourceLoc getLoc() const { return startLoc; }
   SourceLoc getStartLoc() const { return startLoc; }
   SourceLoc getEndLoc() const { return endLoc; }
 
   ArrayRef<LifetimeDescriptor> getSources() const {
-    return {getTrailingObjects<LifetimeDescriptor>(), numSources};
+    return getTrailingObjects(numSources);
   }
 
   std::optional<LifetimeDescriptor> getTargetDescriptor() const {
     return targetDescriptor;
   }
-
-  std::string getString() const {
-    std::string result = "@lifetime(";
-    if (targetDescriptor.has_value()) {
-      result += targetDescriptor->getString();
-      result += ": ";
-    }
-
-    bool firstElem = true;
-    for (auto source : getSources()) {
-      if (!firstElem) {
-        result += ", ";
-      }
-      switch (source.getParsedLifetimeDependenceKind()) {
-      case ParsedLifetimeDependenceKind::Scope:
-        result += "borrow ";
-        break;
-      case ParsedLifetimeDependenceKind::Inherit:
-        result += "copy ";
-        break;
-      default:
-        break;
-      }
-      result += source.getString();
-      firstElem = false;
-    }
-    result += ")";
-    return result;
-  }
 };
 
 class LifetimeDependenceInfo {
@@ -245,19 +208,34 @@ class LifetimeDependenceInfo {
         addressableParamIndicesAndImmortal(addressableParamIndices, isImmortal),
         conditionallyAddressableParamIndices(conditionallyAddressableParamIndices),
         targetIndex(targetIndex) {
-    assert(this->isImmortal() || inheritLifetimeParamIndices ||
+    ASSERT(this->isImmortal() || inheritLifetimeParamIndices ||
            scopeLifetimeParamIndices);
-    // FIXME: This assert can trigger when Optional/Result support ~Escapable use (rdar://147765187)
-    // assert(!inheritLifetimeParamIndices ||
-    //        !inheritLifetimeParamIndices->isEmpty());
-    if (inheritLifetimeParamIndices && inheritLifetimeParamIndices->isEmpty()) {
-      inheritLifetimeParamIndices = nullptr;
-    }
-    assert(!scopeLifetimeParamIndices || !scopeLifetimeParamIndices->isEmpty());
+    ASSERT(!inheritLifetimeParamIndices ||
+           !inheritLifetimeParamIndices->isEmpty());
+    ASSERT(!scopeLifetimeParamIndices || !scopeLifetimeParamIndices->isEmpty());
     assert((!addressableParamIndices
             || !conditionallyAddressableParamIndices
             || conditionallyAddressableParamIndices->isDisjointWith(
               addressableParamIndices)));
+
+    if (CONDITIONAL_ASSERT_enabled()) {
+      // Ensure inherit/scope/addressable param indices are of the same length
+      // or 0.
+      unsigned paramIndicesLength = 0;
+      if (inheritLifetimeParamIndices) {
+        paramIndicesLength = inheritLifetimeParamIndices->getCapacity();
+      }
+      if (scopeLifetimeParamIndices) {
+        ASSERT(paramIndicesLength == 0 ||
+               paramIndicesLength == scopeLifetimeParamIndices->getCapacity());
+        paramIndicesLength = scopeLifetimeParamIndices->getCapacity();
+      }
+      if (addressableParamIndices) {
+        ASSERT(paramIndicesLength == 0 ||
+               paramIndicesLength == addressableParamIndices->getCapacity());
+        paramIndicesLength = addressableParamIndices->getCapacity();
+      }
+    }
   }
 
   operator bool() const { return !empty(); }
@@ -281,6 +259,19 @@ class LifetimeDependenceInfo {
     return addressableParamIndicesAndImmortal.getPointer() != nullptr;
   }
 
+  unsigned getParamIndicesLength() const {
+    if (hasInheritLifetimeParamIndices()) {
+      return getInheritIndices()->getCapacity();
+    }
+    if (hasScopeLifetimeParamIndices()) {
+      return getScopeIndices()->getCapacity();
+    }
+    if (hasAddressableParamIndices()) {
+      return getAddressableIndices()->getCapacity();
+    }
+    return 0;
+  }
+
   IndexSubset *getInheritIndices() const { return inheritLifetimeParamIndices; }
 
   IndexSubset *getScopeIndices() const { return scopeLifetimeParamIndices; }
@@ -316,11 +307,6 @@ class LifetimeDependenceInfo {
       && scopeLifetimeParamIndices->contains(index);
   }
 
-  bool checkAddressable(int index) const {
-    return hasAddressableParamIndices()
-      && getAddressableIndices()->contains(index);
-  }
-
   std::string getString() const;
   void Profile(llvm::FoldingSetNodeID &ID) const;
   void getConcatenatedData(SmallVectorImpl<bool> &concatenatedData) const;
@@ -328,8 +314,7 @@ class LifetimeDependenceInfo {
   /// Builds LifetimeDependenceInfo from a swift decl, either from the explicit
   /// lifetime dependence specifiers or by inference based on types and
   /// ownership modifiers.
-  static std::optional<ArrayRef<LifetimeDependenceInfo>>
-  get(AbstractFunctionDecl *decl);
+  static std::optional<ArrayRef<LifetimeDependenceInfo>> get(ValueDecl *decl);
 
   /// Builds LifetimeDependenceInfo from SIL
   static std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>
@@ -366,6 +351,9 @@ filterEscapableLifetimeDependencies(GenericSignature sig,
         SmallVectorImpl<LifetimeDependenceInfo> &outputs,
         llvm::function_ref<Type (unsigned targetIndex)> getSubstTargetType);
 
+StringRef
+getNameForParsedLifetimeDependenceKind(ParsedLifetimeDependenceKind kind);
+
 } // namespace swift
 
 #endif
diff --git a/include/swift/AST/MacroDefinition.h b/include/swift/AST/MacroDefinition.h
index 17937a9bba82d..7c7538948c43f 100644
--- a/include/swift/AST/MacroDefinition.h
+++ b/include/swift/AST/MacroDefinition.h
@@ -77,9 +77,6 @@ enum class BuiltinMacroKind : uint8_t {
   ExternalMacro,
   /// #isolation, which produces the isolation of the current context
   IsolationMacro,
-  /// #SwiftSettings, which allows for the user to set a compiler setting at
-  /// the file level
-  SwiftSettingsMacro,
 };
 
 /// A single replacement
diff --git a/include/swift/AST/Module.h b/include/swift/AST/Module.h
index bf1a462f308a8..39091dcd3ad78 100644
--- a/include/swift/AST/Module.h
+++ b/include/swift/AST/Module.h
@@ -345,8 +345,6 @@ class ModuleDecl
   /// \see EntryPointInfoTy
   EntryPointInfoTy EntryPointInfo;
 
-  AccessNotesFile accessNotes;
-
   /// Used by the debugger to bypass resilient access to fields.
   bool BypassResilience = false;
 
@@ -415,8 +413,9 @@ class ModuleDecl
   /// imports.
   ImplicitImportList getImplicitImports() const;
 
-  AccessNotesFile &getAccessNotes() { return accessNotes; }
-  const AccessNotesFile &getAccessNotes() const { return accessNotes; }
+  /// Retrieve the access notes to apply for the module, or \c nullptr if there
+  /// are no access notes.
+  const AccessNotesFile *getAccessNotes() const;
 
   /// Return whether the module was imported with resilience disabled. The
   /// debugger does this to access private fields.
@@ -434,11 +433,6 @@ class ModuleDecl
   /// \c nullptr if the source location isn't in this module.
   SourceFile *getSourceFileContainingLocation(SourceLoc loc);
 
-  // Retrieve the buffer ID and source location of the outermost location that
-  // caused the generation of the buffer containing \p loc. \p loc and its
-  // buffer if it isn't in a generated buffer or has no original location.
-  std::pair<unsigned, SourceLoc> getOriginalLocation(SourceLoc loc) const;
-
   /// Creates a map from \c #filePath strings to corresponding \c #fileID
   /// strings, diagnosing any conflicts.
   ///
@@ -823,7 +817,7 @@ class ModuleDecl
     Bits.ModuleDecl.IsConcurrencyChecked = value;
   }
 
-  /// Whether this module has enable strict memory safety checking.
+  /// Whether this module has enabled strict memory safety checking.
   bool strictMemorySafety() const {
     return Bits.ModuleDecl.StrictMemorySafety;
   }
@@ -832,20 +826,21 @@ class ModuleDecl
     Bits.ModuleDecl.StrictMemorySafety = value;
   }
 
-  bool isObjCNameLookupCachePopulated() const {
-    return Bits.ModuleDecl.ObjCNameLookupCachePopulated;
+  /// Whether this module uses deferred code generation.
+  bool deferredCodeGen() const {
+    return Bits.ModuleDecl.DeferredCodeGen;
   }
 
-  void setIsObjCNameLookupCachePopulated(bool value) {
-    Bits.ModuleDecl.ObjCNameLookupCachePopulated = value;
+  void setDeferredCodeGen(bool value = true) {
+    Bits.ModuleDecl.DeferredCodeGen = value;
   }
 
-  bool supportsExtensibleEnums() const {
-    return Bits.ModuleDecl.ExtensibleEnums;
+  bool isObjCNameLookupCachePopulated() const {
+    return Bits.ModuleDecl.ObjCNameLookupCachePopulated;
   }
 
-  void setSupportsExtensibleEnums(bool value = true) {
-    Bits.ModuleDecl.ExtensibleEnums = value;
+  void setIsObjCNameLookupCachePopulated(bool value) {
+    Bits.ModuleDecl.ObjCNameLookupCachePopulated = value;
   }
 
   /// For the main module, retrieves the list of primary source files being
@@ -970,6 +965,10 @@ class ModuleDecl
                          const ModuleDecl *importedModule,
                          llvm::SmallSetVector<Identifier, 4> &spiGroups) const;
 
+  /// Returns true if any import of \p importedModule has the `@preconcurrency`
+  /// attribute.
+  bool isModuleImportedPreconcurrency(const ModuleDecl *importedModule) const;
+
   /// Finds the custom availability domain defined by this module with the
   /// given identifier and if one exists adds it to results.
   void
@@ -977,7 +976,7 @@ class ModuleDecl
                             SmallVectorImpl<AvailabilityDomain> &results) const;
 
   // Is \p attr accessible as an explicitly imported SPI from this module?
-  bool isImportedAsSPI(const SpecializeAttr *attr,
+  bool isImportedAsSPI(const AbstractSpecializeAttr *attr,
                        const ValueDecl *targetDecl) const;
 
   // Is \p spiGroup accessible as an explicitly imported SPI from this module?
@@ -1158,6 +1157,9 @@ class ModuleDecl
   /// \returns true if this module is the "swift" standard library module.
   bool isStdlibModule() const;
 
+  /// \returns true if this module is the "Cxx" module.
+  bool isCxxModule() const;
+
   /// \returns true if this module is the "_Concurrency" standard library module.
   bool isConcurrencyModule() const;
 
diff --git a/include/swift/AST/ModuleDependencies.h b/include/swift/AST/ModuleDependencies.h
index 391b2acc0b4a0..14aaf91b4fe3e 100644
--- a/include/swift/AST/ModuleDependencies.h
+++ b/include/swift/AST/ModuleDependencies.h
@@ -20,8 +20,10 @@
 
 #include "swift/AST/Import.h"
 #include "swift/AST/LinkLibrary.h"
+#include "swift/Basic/Assertions.h"
 #include "swift/Basic/CXXStdlibKind.h"
 #include "swift/Basic/LLVM.h"
+#include "swift/Serialization/Validation.h"
 #include "clang/CAS/CASOptions.h"
 #include "clang/Tooling/DependencyScanning/DependencyScanningService.h"
 #include "clang/Tooling/DependencyScanning/DependencyScanningTool.h"
@@ -30,16 +32,8 @@
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/StringSet.h"
-#include "llvm/CAS/ActionCache.h"
-#include "llvm/CAS/CASProvidingFileSystem.h"
-#include "llvm/CAS/CASReference.h"
 #include "llvm/CAS/CachingOnDiskFileSystem.h"
-#include "llvm/CAS/ObjectStore.h"
-#include "llvm/Support/Error.h"
-#include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Mutex.h"
-#include "llvm/Support/PrefixMapper.h"
-#include "llvm/Support/VirtualFileSystem.h"
 #include <optional>
 #include <string>
 #include <unordered_map>
@@ -55,6 +49,7 @@ class Identifier;
 class CompilerInstance;
 class IRGenOptions;
 class CompilerInvocation;
+class DiagnosticEngine;
 
 /// Which kind of module dependencies we are looking for.
 enum class ModuleDependencyKind : int8_t {
@@ -67,30 +62,7 @@ enum class ModuleDependencyKind : int8_t {
   Clang,
   // Used to model the translation unit's source module
   SwiftSource,
-  // Placeholder dependencies are a kind of dependencies used only by the
-  // dependency scanner. They are swift modules that the scanner will not be
-  // able to locate in its search paths and which are the responsibility of the
-  // scanner's client to ensure are provided.
-  //
-  // Placeholder dependencies will be specified in the scanner's output
-  // dependency graph where it is the responsibility of the scanner's client to
-  // ensure required post-processing takes place to "resolve" them. In order to
-  // do so, the client (swift driver, or any other client build system) is
-  // expected to have access to a full dependency graph of all placeholder
-  // dependencies and be able to replace placeholder nodes in the dependency
-  // graph with their full dependency trees, `uniquing` common dependency module
-  // nodes in the process.
-  //
-  // One example where placeholder dependencies are employed is when using
-  // SwiftPM in Explicit Module Build mode. SwiftPM constructs a build plan for
-  // all targets ahead-of-time. When planning a build for a target that depends
-  // on other targets, the dependency scanning action is not able to locate
-  // dependency target modules, because they have not yet been built. Instead,
-  // the build system treats them as placeholder dependencies and resolves them
-  // with `actual` dependencies in a post-processing step once dependency graphs
-  // of all targets, individually, have been computed.
-  SwiftPlaceholder,
-  LastKind = SwiftPlaceholder + 1
+  LastKind = SwiftSource + 1
 };
 
 /// This is used to idenfity a specific macro plugin dependency.
@@ -123,6 +95,69 @@ struct ModuleDependencyIDHash {
   }
 };
 
+// An iterable view over multiple joined ArrayRefs
+// FIXME: std::ranges::join_view
+template <typename T>
+class JoinedArrayRefView {
+public:
+  class Iterator {
+  public:
+    using iterator_category = std::forward_iterator_tag;
+    using value_type = T;
+    using difference_type = std::ptrdiff_t;
+    using pointer = const T*;
+    using reference = const T&;
+    Iterator(const JoinedArrayRefView *parent, size_t memberIndex,
+             size_t elementIndex)
+        : parentView(parent), collectionIndex(memberIndex),
+          elementIndex(elementIndex) {
+      checkAdvance();
+    }
+    const T &operator*() const {
+      return (parentView->memberCollections[collectionIndex])[elementIndex];
+    }
+    const T *operator->() const {
+      return &(parentView->memberCollections[collectionIndex])[elementIndex];
+    }
+    Iterator &operator++() {
+      ++elementIndex;
+      checkAdvance();
+      return *this;
+    }
+    bool operator==(const Iterator &other) const {
+      return collectionIndex == other.collectionIndex &&
+             elementIndex == other.elementIndex;
+    }
+    bool operator!=(const Iterator &other) const { return !(*this == other); }
+
+  private:
+    const JoinedArrayRefView *parentView;
+    size_t collectionIndex;
+    size_t elementIndex;
+
+    void checkAdvance() {
+      while (collectionIndex < parentView->memberCollections.size() &&
+             elementIndex >= parentView->memberCollections[collectionIndex].size()) {
+        ++collectionIndex;
+        elementIndex = 0;
+      }
+    }
+  };
+
+  Iterator begin() const { return Iterator(this, 0, 0); }
+  Iterator end() const { return Iterator(this, memberCollections.size(), 0); }
+
+  template <typename... Arrays>
+  JoinedArrayRefView(Arrays ...arrs) {
+    memberCollections.reserve(sizeof...(arrs));
+    (memberCollections.push_back(arrs), ...);
+  }
+
+private:
+  std::vector<ArrayRef<T>> memberCollections;
+};
+using ModuleDependencyIDCollectionView = JoinedArrayRefView<ModuleDependencyID>;
+
 using ModuleDependencyIDSet =
     std::unordered_set<ModuleDependencyID, ModuleDependencyIDHash>;
 using ModuleDependencyIDSetVector =
@@ -154,25 +189,39 @@ struct ScannerImportStatementInfo {
     uint32_t columnNumber;
   };
 
-  ScannerImportStatementInfo(std::string importIdentifier, bool isExported)
-      : importLocations(), importIdentifier(importIdentifier),
-        isExported(isExported) {}
+  ScannerImportStatementInfo(std::string importIdentifier)
+      : importIdentifier(importIdentifier), importLocations(),
+        isExported(false), accessLevel(AccessLevel::Public) {}
+
+  ScannerImportStatementInfo(std::string importIdentifier, bool isExported,
+                             AccessLevel accessLevel)
+      : importIdentifier(importIdentifier), importLocations(),
+        isExported(isExported), accessLevel(accessLevel) {}
 
   ScannerImportStatementInfo(std::string importIdentifier, bool isExported,
+                             AccessLevel accessLevel,
                              ImportDiagnosticLocationInfo location)
-      : importLocations({location}), importIdentifier(importIdentifier),
-        isExported(isExported) {}
+      : importIdentifier(importIdentifier), importLocations({location}),
+        isExported(isExported), accessLevel(accessLevel) {}
+
+  ScannerImportStatementInfo(std::string importIdentifier, bool isExported,
+                             AccessLevel accessLevel,
+                             SmallVector<ImportDiagnosticLocationInfo, 4> locations)
+      : importIdentifier(importIdentifier), importLocations(locations),
+        isExported(isExported), accessLevel(accessLevel) {}
 
   void addImportLocation(ImportDiagnosticLocationInfo location) {
     importLocations.push_back(location);
   }
 
-  /// Buffer, line & column number of the import statement
-  SmallVector<ImportDiagnosticLocationInfo, 4> importLocations;
   /// Imported module string. e.g. "Foo.Bar" in 'import Foo.Bar'
   std::string importIdentifier;
+  /// Buffer, line & column number of the import statement
+  SmallVector<ImportDiagnosticLocationInfo, 4> importLocations;
   /// Is this an @_exported import
   bool isExported;
+  /// Access level of this dependency
+  AccessLevel accessLevel;
 };
 
 /// Base class for the variant storage of ModuleDependencyInfo.
@@ -228,6 +277,11 @@ class ModuleDependencyInfoStorageBase {
   /// The macro dependencies.
   std::map<std::string, MacroPluginDependency> macroDependencies;
 
+  /// A list of Clang modules that are visible to this Swift module. This
+  /// includes both direct Clang modules as well as transitive Clang
+  /// module dependencies when they are exported
+  llvm::StringSet<> visibleClangModules;
+
   /// ModuleDependencyInfo is finalized (with all transitive dependencies
   /// and inputs).
   bool finalized;
@@ -400,8 +454,10 @@ class SwiftBinaryModuleDependencyStorage
       StringRef sourceInfoPath,
       ArrayRef<ScannerImportStatementInfo> moduleImports,
       ArrayRef<ScannerImportStatementInfo> optionalModuleImports,
-      ArrayRef<LinkLibrary> linkLibraries, StringRef headerImport,
-      StringRef definingModuleInterface, bool isFramework, bool isStatic,
+      ArrayRef<LinkLibrary> linkLibraries,
+      ArrayRef<serialization::SearchPath> serializedSearchPaths,
+      StringRef headerImport, StringRef definingModuleInterface,
+      bool isFramework, bool isStatic, bool isBuiltWithCxxInterop,
       StringRef moduleCacheKey, StringRef userModuleVersion)
       : ModuleDependencyInfoStorageBase(ModuleDependencyKind::SwiftBinary,
                                         moduleImports, optionalModuleImports,
@@ -409,7 +465,9 @@ class SwiftBinaryModuleDependencyStorage
         compiledModulePath(compiledModulePath), moduleDocPath(moduleDocPath),
         sourceInfoPath(sourceInfoPath), headerImport(headerImport),
         definingModuleInterfacePath(definingModuleInterface),
+        serializedSearchPaths(serializedSearchPaths),
         isFramework(isFramework), isStatic(isStatic),
+        isBuiltWithCxxInterop(isBuiltWithCxxInterop),
         userModuleVersion(userModuleVersion) {}
 
   ModuleDependencyInfoStorageBase *clone() const override {
@@ -435,6 +493,9 @@ class SwiftBinaryModuleDependencyStorage
   /// Source files on which the header inputs depend.
   std::vector<std::string> headerSourceFiles;
 
+  /// Search paths this module was built with which got serialized
+  std::vector<serialization::SearchPath> serializedSearchPaths;
+
   /// (Clang) modules on which the header inputs depend.
   std::vector<ModuleDependencyID> headerModuleDependencies;
 
@@ -444,6 +505,10 @@ class SwiftBinaryModuleDependencyStorage
   /// A flag that indicates this dependency is associated with a static archive
   const bool isStatic;
 
+  /// A flag that indicates this dependency module was built
+  /// with C++ interop enabled
+  const bool isBuiltWithCxxInterop;
+
   /// The user module version of this binary module.
   const std::string userModuleVersion;
 
@@ -524,39 +589,6 @@ class ClangModuleDependencyStorage : public ModuleDependencyInfoStorageBase {
   }
 };
 
-/// Describes an placeholder Swift module dependency module stub.
-///
-/// This class is mostly an implementation detail for \c ModuleDependencyInfo.
-
-class SwiftPlaceholderModuleDependencyStorage
-    : public ModuleDependencyInfoStorageBase {
-public:
-  SwiftPlaceholderModuleDependencyStorage(StringRef compiledModulePath,
-                                          StringRef moduleDocPath,
-                                          StringRef sourceInfoPath)
-      : ModuleDependencyInfoStorageBase(ModuleDependencyKind::SwiftPlaceholder, {}, {},
-                                        {}),
-        compiledModulePath(compiledModulePath), moduleDocPath(moduleDocPath),
-        sourceInfoPath(sourceInfoPath) {}
-
-  ModuleDependencyInfoStorageBase *clone() const override {
-    return new SwiftPlaceholderModuleDependencyStorage(*this);
-  }
-
-  /// The path to the .swiftmodule file.
-  const std::string compiledModulePath;
-
-  /// The path to the .swiftModuleDoc file.
-  const std::string moduleDocPath;
-
-  /// The path to the .swiftSourceInfo file.
-  const std::string sourceInfoPath;
-
-  static bool classof(const ModuleDependencyInfoStorageBase *base) {
-    return base->dependencyKind == ModuleDependencyKind::SwiftPlaceholder;
-  }
-};
-
 // MARK: Module Dependency Info
 /// Describes the dependencies of a given module.
 ///
@@ -607,15 +639,17 @@ class ModuleDependencyInfo {
       StringRef sourceInfoPath,
       ArrayRef<ScannerImportStatementInfo> moduleImports,
       ArrayRef<ScannerImportStatementInfo> optionalModuleImports,
-      ArrayRef<LinkLibrary> linkLibraries, StringRef headerImport,
-      StringRef definingModuleInterface, bool isFramework,
-      bool isStatic, StringRef moduleCacheKey, StringRef userModuleVer) {
+      ArrayRef<LinkLibrary> linkLibraries,
+      ArrayRef<serialization::SearchPath> serializedSearchPaths,
+      StringRef headerImport, StringRef definingModuleInterface,
+      bool isFramework, bool isStatic, bool isBuiltWithCxxInterop,
+      StringRef moduleCacheKey, StringRef userModuleVer) {
     return ModuleDependencyInfo(
         std::make_unique<SwiftBinaryModuleDependencyStorage>(
             compiledModulePath, moduleDocPath, sourceInfoPath, moduleImports,
-            optionalModuleImports, linkLibraries, headerImport,
-            definingModuleInterface,isFramework, isStatic, moduleCacheKey,
-            userModuleVer));
+            optionalModuleImports, linkLibraries, serializedSearchPaths,
+            headerImport, definingModuleInterface,isFramework, isStatic,
+            isBuiltWithCxxInterop, moduleCacheKey, userModuleVer));
   }
 
   /// Describe the main Swift module.
@@ -655,16 +689,6 @@ class ModuleDependencyInfo {
         CASFileSystemRootID, clangIncludeTreeRoot, moduleCacheKey, IsSystem));
   }
 
-  /// Describe a placeholder dependency swift module.
-  static ModuleDependencyInfo
-  forPlaceholderSwiftModuleStub(StringRef compiledModulePath,
-                                StringRef moduleDocPath,
-                                StringRef sourceInfoPath) {
-    return ModuleDependencyInfo(
-        std::make_unique<SwiftPlaceholderModuleDependencyStorage>(
-            compiledModulePath, moduleDocPath, sourceInfoPath));
-  }
-
   /// Retrieve the module-level imports.
   ArrayRef<ScannerImportStatementInfo> getModuleImports() const {
     return storage->moduleImports;
@@ -689,7 +713,7 @@ class ModuleDependencyInfo {
     storage->importedSwiftModules.assign(dependencyIDs.begin(),
                                          dependencyIDs.end());
   }
-  const ArrayRef<ModuleDependencyID> getImportedSwiftDependencies() const {
+  ArrayRef<ModuleDependencyID> getImportedSwiftDependencies() const {
     return storage->importedSwiftModules;
   }
 
@@ -698,7 +722,7 @@ class ModuleDependencyInfo {
     storage->importedClangModules.assign(dependencyIDs.begin(),
                                          dependencyIDs.end());
   }
-  const ArrayRef<ModuleDependencyID> getImportedClangDependencies() const {
+  ArrayRef<ModuleDependencyID> getImportedClangDependencies() const {
     return storage->importedClangModules;
   }
 
@@ -732,7 +756,7 @@ class ModuleDependencyInfo {
     }
     }
   }
-  const ArrayRef<ModuleDependencyID> getHeaderClangDependencies() const {
+  ArrayRef<ModuleDependencyID> getHeaderClangDependencies() const {
     switch (getKind()) {
     case swift::ModuleDependencyKind::SwiftInterface: {
       auto swiftInterfaceStorage =
@@ -760,21 +784,20 @@ class ModuleDependencyInfo {
     storage->swiftOverlayDependencies.assign(dependencyIDs.begin(),
                                              dependencyIDs.end());
   }
-  const ArrayRef<ModuleDependencyID> getSwiftOverlayDependencies() const {
+  ArrayRef<ModuleDependencyID> getSwiftOverlayDependencies() const {
     return storage->swiftOverlayDependencies;
   }
-
-  void
-  setCrossImportOverlayDependencies(const ArrayRef<ModuleDependencyID> dependencyIDs) {
+  void setCrossImportOverlayDependencies(
+      const ModuleDependencyIDCollectionView dependencyIDs) {
     assert(isSwiftModule());
     storage->crossImportOverlayModules.assign(dependencyIDs.begin(),
                                               dependencyIDs.end());
   }
-  const ArrayRef<ModuleDependencyID> getCrossImportOverlayDependencies() const {
+  ArrayRef<ModuleDependencyID> getCrossImportOverlayDependencies() const {
     return storage->crossImportOverlayModules;
   }
 
-  const ArrayRef<LinkLibrary> getLinkLibraries() const {
+  ArrayRef<LinkLibrary> getLinkLibraries() const {
     return storage->linkLibraries;
   }
 
@@ -783,15 +806,10 @@ class ModuleDependencyInfo {
     storage->linkLibraries.assign(linkLibraries.begin(), linkLibraries.end());
   }
 
-  const ArrayRef<std::string> getAuxiliaryFiles() const {
+  ArrayRef<std::string> getAuxiliaryFiles() const {
     return storage->auxiliaryFiles;
   }
 
-  void
-  setAuxiliaryFiles(const ArrayRef<std::string> auxiliaryFiles) {
-    storage->auxiliaryFiles.assign(auxiliaryFiles.begin(), auxiliaryFiles.end());
-  }
-
   bool isStaticLibrary() const {
     if (auto *detail = getAsSwiftInterfaceModule())
       return detail->isStatic;
@@ -800,7 +818,7 @@ class ModuleDependencyInfo {
     return false;
   }
 
-  const ArrayRef<std::string> getHeaderInputSourceFiles() const {
+  ArrayRef<std::string> getHeaderInputSourceFiles() const {
     if (auto *detail = getAsSwiftInterfaceModule())
       return detail->textualModuleDetails.bridgingSourceFiles;
     if (auto *detail = getAsSwiftSourceModule())
@@ -810,7 +828,7 @@ class ModuleDependencyInfo {
     return {};
   }
 
-  std::vector<std::string> getCommandline() const {
+  ArrayRef<std::string> getCommandline() const {
     if (auto *detail = getAsClangModule())
       return detail->buildCommandLine;
     if (auto *detail = getAsSwiftInterfaceModule())
@@ -833,7 +851,7 @@ class ModuleDependencyInfo {
     llvm_unreachable("Unexpected type");
   }
 
-  std::vector<std::string> getBridgingHeaderCommandline() const {
+  ArrayRef<std::string> getBridgingHeaderCommandline() const {
     if (auto *detail = getAsSwiftSourceModule())
       return detail->bridgingHeaderBuildCommandLine;
     return {};
@@ -872,7 +890,17 @@ class ModuleDependencyInfo {
       cast<ClangModuleDependencyStorage>(storage.get())->CASFileSystemRootID =
           rootID;
     else
-      llvm_unreachable("Unexpected type");
+      llvm_unreachable("Unexpected module dependency kind");
+  }
+
+  llvm::StringSet<> &getVisibleClangModules() const {
+    return storage->visibleClangModules;
+  }
+
+  void
+  addVisibleClangModules(const std::vector<std::string> &moduleNames) const {
+    storage->visibleClangModules.insert(moduleNames.begin(),
+                                        moduleNames.end());
   }
 
   /// Whether explicit input paths of all the module dependencies
@@ -888,7 +916,7 @@ class ModuleDependencyInfo {
   bool isTestableImport(StringRef moduleName) const;
 
   /// Whether the dependencies are for a Swift module: either Textual, Source,
-  /// Binary, or Placeholder.
+  /// or Binary
   bool isSwiftModule() const;
 
   /// Whether the dependencies are for a textual interface Swift module or a
@@ -904,9 +932,6 @@ class ModuleDependencyInfo {
   /// Whether the dependencies are for a binary Swift module.
   bool isSwiftBinaryModule() const;
 
-  /// Whether this represents a placeholder module stub
-  bool isSwiftPlaceholderModule() const;
-
   /// Whether the dependencies are for a Clang module.
   bool isClangModule() const;
 
@@ -925,13 +950,16 @@ class ModuleDependencyInfo {
   /// Retrieve the dependencies for a Clang module.
   const ClangModuleDependencyStorage *getAsClangModule() const;
 
-  /// Retrieve the dependencies for a placeholder dependency module stub.
-  const SwiftPlaceholderModuleDependencyStorage *
-  getAsPlaceholderDependencyModule() const;
+  /// Get the path to the module-defining file:
+  /// `SwiftInterface`: Textual Interface path
+  /// `SwiftBinary`: Binary module path
+  /// `Clang`: Module map path
+  std::string getModuleDefiningPath() const;
 
   /// Add a dependency on the given module, if it was not already in the set.
   void
   addOptionalModuleImport(StringRef module, bool isExported,
+                          AccessLevel accessLevel,
                           llvm::StringSet<> *alreadyAddedModules = nullptr);
 
   /// Add all of the module imports in the given source
@@ -942,12 +970,14 @@ class ModuleDependencyInfo {
 
   /// Add a dependency on the given module, if it was not already in the set.
   void addModuleImport(ImportPath::Module module, bool isExported,
+                       AccessLevel accessLevel,
                        llvm::StringSet<> *alreadyAddedModules = nullptr,
                        const SourceManager *sourceManager = nullptr,
                        SourceLoc sourceLocation = SourceLoc());
 
   /// Add a dependency on the given module, if it was not already in the set.
   void addModuleImport(StringRef module, bool isExported,
+                       AccessLevel accessLevel,
                        llvm::StringSet<> *alreadyAddedModules = nullptr,
                        const SourceManager *sourceManager = nullptr,
                        SourceLoc sourceLocation = SourceLoc());
@@ -999,33 +1029,8 @@ using ModuleNameToDependencyMap = llvm::StringMap<ModuleDependencyInfo>;
 using ModuleDependenciesKindMap =
     std::unordered_map<ModuleDependencyKind, ModuleNameToDependencyMap,
                        ModuleDependencyKindHash>;
-
-// MARK: SwiftDependencyTracker
-/// Track swift dependency
-class SwiftDependencyTracker {
-public:
-  SwiftDependencyTracker(llvm::cas::CachingOnDiskFileSystem &FS,
-                         llvm::PrefixMapper *Mapper,
-                         const CompilerInvocation &CI);
-
-  void startTracking(bool includeCommonDeps = true);
-  void trackFile(const Twine &path);
-  llvm::Expected<llvm::cas::ObjectProxy> createTreeFromDependencies();
-
-private:
-  llvm::IntrusiveRefCntPtr<llvm::cas::CachingOnDiskFileSystem> FS;
-  llvm::PrefixMapper *Mapper;
-
-  struct FileEntry {
-    llvm::cas::ObjectRef FileRef;
-    size_t Size;
-
-    FileEntry(llvm::cas::ObjectRef FileRef, size_t Size)
-        : FileRef(FileRef), Size(Size) {}
-  };
-  llvm::StringMap<FileEntry> CommonFiles;
-  std::map<std::string, FileEntry> TrackedFiles;
-};
+using BridgeClangDependencyCallback = llvm::function_ref<ModuleDependencyInfo(
+    const clang::tooling::dependencies::ModuleDeps &clangModuleDep)>;
 
 // MARK: SwiftDependencyScanningService
 /// A carrier of state shared among possibly multiple invocations of the
@@ -1038,24 +1043,6 @@ class SwiftDependencyScanningService {
   std::optional<clang::tooling::dependencies::DependencyScanningService>
       ClangScanningService;
 
-  /// CachingOnDiskFileSystem for dependency tracking.
-  llvm::IntrusiveRefCntPtr<llvm::cas::CachingOnDiskFileSystem> CacheFS;
-
-  /// If use clang include tree.
-  bool UseClangIncludeTree = false;
-
-  /// CAS Instance.
-  std::shared_ptr<llvm::cas::ObjectStore> CAS;
-  std::shared_ptr<llvm::cas::ActionCache> ActionCache;
-
-  /// File prefix mapper.
-  std::unique_ptr<llvm::PrefixMapper> Mapper;
-
-  /// The global file system cache.
-  std::optional<
-      clang::tooling::dependencies::DependencyScanningFilesystemSharedCache>
-      SharedFilesystemCache;
-
   /// Shared state mutual-exclusivity lock
   mutable llvm::sys::SmartMutex<true> ScanningServiceGlobalLock;
 
@@ -1067,60 +1054,6 @@ class SwiftDependencyScanningService {
   operator=(const SwiftDependencyScanningService &) = delete;
   virtual ~SwiftDependencyScanningService() {}
 
-  /// Query the service's filesystem cache
-  clang::tooling::dependencies::DependencyScanningFilesystemSharedCache &getSharedCache() {
-    assert(SharedFilesystemCache && "Expected a shared cache");
-    return *SharedFilesystemCache;
-  }
-
-  /// Query the service's filesystem cache
-  clang::tooling::dependencies::DependencyScanningFilesystemSharedCache &
-  getSharedFilesystemCache() {
-    assert(SharedFilesystemCache && "Expected a shared cache");
-    return *SharedFilesystemCache;
-  }
-
-  llvm::cas::CachingOnDiskFileSystem &getSharedCachingFS() const {
-    assert(CacheFS && "Expect CachingOnDiskFileSystem");
-    return *CacheFS;
-  }
-
-  llvm::cas::ObjectStore &getCAS() const {
-    assert(CAS && "Expect CAS available");
-    return *CAS;
-  }
-
-  std::optional<SwiftDependencyTracker>
-  createSwiftDependencyTracker(const CompilerInvocation &CI) {
-    if (!CacheFS)
-      return std::nullopt;
-
-    return SwiftDependencyTracker(*CacheFS, Mapper.get(), CI);
-  }
-
-  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> getClangScanningFS() const {
-    if (UseClangIncludeTree)
-      return llvm::cas::createCASProvidingFileSystem(
-          CAS, llvm::vfs::createPhysicalFileSystem());
-
-    if (CacheFS)
-      return CacheFS->createProxyFS();
-
-    return llvm::vfs::createPhysicalFileSystem();
-  }
-
-  bool hasPathMapping() const {
-    return Mapper && !Mapper->getMappings().empty();
-  }
-  llvm::PrefixMapper *getPrefixMapper() const { return Mapper.get(); }
-  std::string remapPath(StringRef Path) const {
-    if (!Mapper)
-      return Path.str();
-    return Mapper->mapToString(Path);
-  }
-
-  bool hasCAS() const { return (bool)CAS; }
-
   /// Setup caching service.
   bool setupCachingDependencyScanningService(CompilerInstance &Instance);
 
@@ -1134,13 +1067,10 @@ class SwiftDependencyScanningService {
 
 // MARK: ModuleDependenciesCache
 /// This "local" dependencies cache persists only for the duration of a given
-/// scanning action, and wraps an instance of a `SwiftDependencyScanningService`
-/// which may carry cached scanning information from prior scanning actions.
-/// This cache maintains a store of references to all dependencies found within
-/// the current scanning action (with their values stored in the global Cache).
+/// scanning action, and maintains a store of references to all dependencies
+/// found within the current scanning action.
 class ModuleDependenciesCache {
 private:
-  SwiftDependencyScanningService &globalScanningService;
   /// Discovered dependencies
   ModuleDependenciesKindMap ModuleDependenciesMap;
   /// Set containing all of the Clang modules that have already been seen.
@@ -1149,10 +1079,6 @@ class ModuleDependenciesCache {
   std::string mainScanModuleName;
   /// The context hash of the current scanning invocation
   std::string scannerContextHash;
-  /// The location of where the explicitly-built modules will be output to
-  std::string moduleOutputPath;
-  /// The location of where the explicitly-built SDK modules will be output to
-  std::string sdkModuleOutputPath;
   /// The timestamp of the beginning of the scanning query action
   /// using this cache
   const llvm::sys::TimePoint<> scanInitializationTime;
@@ -1165,10 +1091,7 @@ class ModuleDependenciesCache {
   getDependencyReferencesMap(ModuleDependencyKind kind) const;
 
 public:
-  ModuleDependenciesCache(SwiftDependencyScanningService &globalScanningService,
-                          const std::string &mainScanModuleName,
-                          const std::string &moduleOutputPath,
-                          const std::string &sdkModuleOutputPath,
+  ModuleDependenciesCache(const std::string &mainScanModuleName,
                           const std::string &scanningContextHash);
   ModuleDependenciesCache(const ModuleDependenciesCache &) = delete;
   ModuleDependenciesCache &operator=(const ModuleDependenciesCache &) = delete;
@@ -1189,12 +1112,6 @@ class ModuleDependenciesCache {
   /// Whether we have cached dependency information for the given Swift module.
   bool hasSwiftDependency(StringRef moduleName) const;
 
-  SwiftDependencyScanningService &getScanService() {
-    return globalScanningService;
-  }
-  const SwiftDependencyScanningService &getScanService() const {
-    return globalScanningService;
-  }
   const llvm::DenseSet<clang::tooling::dependencies::ModuleID> &
   getAlreadySeenClangModules() const {
     return alreadySeenClangModules;
@@ -1202,16 +1119,18 @@ class ModuleDependenciesCache {
   void addSeenClangModule(clang::tooling::dependencies::ModuleID newModule) {
     alreadySeenClangModules.insert(newModule);
   }
-  StringRef getModuleOutputPath() const { return moduleOutputPath; }
-  StringRef getSDKModuleOutputPath() const { return sdkModuleOutputPath; }
 
   /// Query all dependencies
-  ModuleDependencyIDSetVector
+  ModuleDependencyIDCollectionView
   getAllDependencies(const ModuleDependencyID &moduleID) const;
 
+  /// Query all directly-imported dependencies
+  ModuleDependencyIDCollectionView
+  getDirectImportedDependencies(const ModuleDependencyID &moduleID) const;
+
   /// Query all Clang module dependencies.
-  ModuleDependencyIDSetVector
-  getClangDependencies(const ModuleDependencyID &moduleID) const;
+  ModuleDependencyIDCollectionView
+  getAllClangDependencies(const ModuleDependencyID &moduleID) const;
 
   /// Query all directly-imported Swift dependencies
   llvm::ArrayRef<ModuleDependencyID>
@@ -1228,6 +1147,9 @@ class ModuleDependenciesCache {
   /// Query all cross-import overlay dependencies
   llvm::ArrayRef<ModuleDependencyID>
   getCrossImportOverlayDependencies(const ModuleDependencyID &moduleID) const;
+  /// Query all visible Clang modules for a given Swift dependency
+  llvm::StringSet<>&
+  getVisibleClangModules(ModuleDependencyID moduleID) const;
 
   /// Look for module dependencies for a module with the given ID
   ///
@@ -1258,8 +1180,11 @@ class ModuleDependenciesCache {
   void recordDependency(StringRef moduleName,
                         ModuleDependencyInfo dependencies);
 
-  /// Record dependencies for the given module collection.
-  void recordDependencies(ModuleDependencyVector moduleDependencies);
+  /// Record dependencies for the given collection of Clang modules.
+  void recordClangDependencies(
+      const clang::tooling::dependencies::ModuleDepsGraph &dependencies,
+      DiagnosticEngine &diags,
+      BridgeClangDependencyCallback bridgeClangModule);
 
   /// Update stored dependencies for the given module.
   void updateDependency(ModuleDependencyID moduleID,
@@ -1289,9 +1214,13 @@ class ModuleDependenciesCache {
   setHeaderClangDependencies(ModuleDependencyID moduleID,
                              const ArrayRef<ModuleDependencyID> dependencyIDs);
   /// Resolve this module's cross-import overlay dependencies
+  void setCrossImportOverlayDependencies(
+    ModuleDependencyID moduleID,
+    const ModuleDependencyIDCollectionView dependencyIDs);
+  /// Add to this module's set of visible Clang modules
   void
-  setCrossImportOverlayDependencies(ModuleDependencyID moduleID,
-                                    const ArrayRef<ModuleDependencyID> dependencyIDs);
+  addVisibleClangModules(ModuleDependencyID moduleID,
+                         const std::vector<std::string> &moduleNames);
 
   StringRef getMainModuleName() const { return mainScanModuleName; }
 
diff --git a/include/swift/AST/ModuleLoader.h b/include/swift/AST/ModuleLoader.h
index 3cde841b0b65f..8411c80dd2169 100644
--- a/include/swift/AST/ModuleLoader.h
+++ b/include/swift/AST/ModuleLoader.h
@@ -24,8 +24,6 @@
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/Located.h"
 #include "swift/Basic/SourceLoc.h"
-#include "clang/Basic/FileManager.h"
-#include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/TinyPtrVector.h"
@@ -38,11 +36,8 @@ class FileCollectorBase;
 class PrefixMapper;
 namespace vfs {
 class OutputBackend;
-}
-namespace cas {
-class CachingOnDiskFileSystem;
-}
-}
+} // namespace vfs
+} // namespace llvm
 
 namespace clang {
 class DependencyCollector;
@@ -367,17 +362,6 @@ class ModuleLoader {
   /// Discover overlays declared alongside this file and add information about
   /// them to it.
   void findOverlayFiles(SourceLoc diagLoc, ModuleDecl *module, FileUnit *file);
-
-  /// Retrieve the dependencies for the given, named module, or \c None
-  /// if no such module exists.
-  virtual llvm::SmallVector<std::pair<ModuleDependencyID, ModuleDependencyInfo>, 1>
-  getModuleDependencies(Identifier moduleName,
-                        StringRef moduleOutputPath, StringRef sdkModuleOutputPath,
-                        const llvm::DenseSet<clang::tooling::dependencies::ModuleID> &alreadySeenClangModules,
-                        clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-                        InterfaceSubContextDelegate &delegate,
-                        llvm::PrefixMapper *mapper = nullptr,
-                        bool isTestableImport = false) = 0;
 };
 
 } // namespace swift
diff --git a/include/swift/AST/NameLookup.h b/include/swift/AST/NameLookup.h
index d678f9a7c3254..262f41f7c5bf1 100644
--- a/include/swift/AST/NameLookup.h
+++ b/include/swift/AST/NameLookup.h
@@ -604,6 +604,11 @@ void forEachPotentialAttachedMacro(
 
 /// Describes an inherited nominal entry.
 struct InheritedNominalEntry : Located<NominalTypeDecl *> {
+  /// The `TypeRepr` of the inheritance clause entry from which this nominal was
+  /// sourced, if any. For example, if this is a conformance to `Y` declared as
+  /// `struct S: X, Y & Z {}`, this is the `TypeRepr` for `Y & Z`.
+  TypeRepr *inheritedTypeRepr;
+
   ConformanceAttributes attributes;
 
   /// Whether this inherited entry was suppressed via "~".
@@ -612,10 +617,10 @@ struct InheritedNominalEntry : Located<NominalTypeDecl *> {
   InheritedNominalEntry() { }
 
   InheritedNominalEntry(NominalTypeDecl *item, SourceLoc loc,
-                        ConformanceAttributes attributes,
-                        bool isSuppressed)
-      : Located(item, loc), attributes(attributes),
-        isSuppressed(isSuppressed) {}
+                        TypeRepr *inheritedTypeRepr,
+                        ConformanceAttributes attributes, bool isSuppressed)
+      : Located(item, loc), inheritedTypeRepr(inheritedTypeRepr),
+        attributes(attributes), isSuppressed(isSuppressed) {}
 };
 
 /// Retrieve the set of nominal type declarations that are directly
diff --git a/include/swift/AST/NameLookupRequests.h b/include/swift/AST/NameLookupRequests.h
index 36fe7b6974dbe..0ce342507dfc7 100644
--- a/include/swift/AST/NameLookupRequests.h
+++ b/include/swift/AST/NameLookupRequests.h
@@ -267,7 +267,7 @@ class HasMissingDesignatedInitializersRequest :
 /// Request the nominal declaration extended by a given extension declaration.
 class ExtendedNominalRequest
     : public SimpleRequest<
-          ExtendedNominalRequest, NominalTypeDecl *(ExtensionDecl *),
+          ExtendedNominalRequest, NominalTypeDecl *(const ExtensionDecl *),
           RequestFlags::SeparatelyCached | RequestFlags::DependencySink> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -276,8 +276,7 @@ class ExtendedNominalRequest
   friend SimpleRequest;
 
   // Evaluation.
-  NominalTypeDecl *
-  evaluate(Evaluator &evaluator, ExtensionDecl *ext) const;
+  NominalTypeDecl * evaluate(Evaluator &evaluator, const ExtensionDecl *ext) const;
 
 public:
   // Separate caching.
@@ -651,7 +650,7 @@ class OperatorLookupDescriptor final {
   DeclContext *getDC() const {
     if (auto *module = getModule())
       return module;
-    return fileOrModule.get<FileUnit *>();
+    return cast<FileUnit *>(fileOrModule);
   }
 
   friend llvm::hash_code hash_value(const OperatorLookupDescriptor &desc) {
diff --git a/include/swift/AST/NameLookupTypeIDZone.def b/include/swift/AST/NameLookupTypeIDZone.def
index a025901ece813..584e39f862771 100644
--- a/include/swift/AST/NameLookupTypeIDZone.def
+++ b/include/swift/AST/NameLookupTypeIDZone.def
@@ -32,7 +32,7 @@ SWIFT_REQUEST(NameLookup, DirectPrecedenceGroupLookupRequest,
               TinyPtrVector<PrecedenceGroupDecl *>(OperatorLookupDescriptor),
               Uncached, NoLocationInfo)
 SWIFT_REQUEST(NameLookup, ExtendedNominalRequest,
-              NominalTypeDecl *(ExtensionDecl *), SeparatelyCached,
+              NominalTypeDecl *(const ExtensionDecl *), SeparatelyCached,
               NoLocationInfo)
 SWIFT_REQUEST(NameLookup, GenericParamListRequest,
               GenericParamList *(GenericContext *), SeparatelyCached,
diff --git a/include/swift/AST/ParameterList.h b/include/swift/AST/ParameterList.h
index 344db0c3f045d..0ed8c758d5a6f 100644
--- a/include/swift/AST/ParameterList.h
+++ b/include/swift/AST/ParameterList.h
@@ -87,10 +87,10 @@ class alignas(ParamDecl *) ParameterList final :
   ParamDecl *back() const { return getArray().back(); }
 
   MutableArrayRef<ParamDecl*> getArray() {
-    return {getTrailingObjects<ParamDecl*>(), numParameters};
+    return getTrailingObjects(numParameters);
   }
   ArrayRef<ParamDecl*> getArray() const {
-    return {getTrailingObjects<ParamDecl*>(), numParameters};
+    return getTrailingObjects(numParameters);
   }
 
   size_t size() const {
diff --git a/include/swift/AST/Pattern.h b/include/swift/AST/Pattern.h
index 4d827607c85c9..dc2a836ed0bc5 100644
--- a/include/swift/AST/Pattern.h
+++ b/include/swift/AST/Pattern.h
@@ -349,10 +349,10 @@ class TuplePattern final : public Pattern,
   }
 
   MutableArrayRef<TuplePatternElt> getElements() {
-    return {getTrailingObjects<TuplePatternElt>(), getNumElements()};
+    return getTrailingObjects(getNumElements());
   }
   ArrayRef<TuplePatternElt> getElements() const {
-    return {getTrailingObjects<TuplePatternElt>(), getNumElements()};
+    return getTrailingObjects(getNumElements());
   }
 
   const TuplePatternElt &getElement(unsigned i) const {return getElements()[i];}
@@ -617,10 +617,10 @@ class EnumElementPattern : public Pattern {
   }
 
   Expr *getUnresolvedOriginalExpr() const {
-    return ElementDeclOrUnresolvedOriginalExpr.get<Expr*>();
+    return cast<Expr *>(ElementDeclOrUnresolvedOriginalExpr);
   }
   bool hasUnresolvedOriginalExpr() const {
-    return ElementDeclOrUnresolvedOriginalExpr.is<Expr*>();
+    return isa<Expr *>(ElementDeclOrUnresolvedOriginalExpr);
   }
   void setUnresolvedOriginalExpr(Expr *e) {
     ElementDeclOrUnresolvedOriginalExpr = e;
diff --git a/include/swift/AST/PlatformKind.h b/include/swift/AST/PlatformKind.h
index a8a869a36777a..3b3f98581c464 100644
--- a/include/swift/AST/PlatformKind.h
+++ b/include/swift/AST/PlatformKind.h
@@ -1,103 +1,38 @@
-//===--- PlatformKind.h - Swift Language Platform Kinds ---------*- C++ -*-===//
+//===--- AST/PlatformKind.h - Swift Language Platform Kinds -----*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//
-//
-// This file defines the platform kinds for API availability.
-//
+///
+/// This file defines the platform kinds for API availability.
+///
 //===----------------------------------------------------------------------===//
 
 #ifndef SWIFT_AST_PLATFORM_KIND_H
 #define SWIFT_AST_PLATFORM_KIND_H
 
-#include "swift/Basic/LLVM.h"
-#include "swift/Config.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/Support/VersionTuple.h"
-#include <optional>
+/// `PlatformKind.h` is imported into Swift. Be *very* careful with what you
+/// include here and keep these includes minimal!
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
+#include "swift/Basic/SwiftBridging.h"
+#include <stdint.h>
 
 namespace swift {
 
-class LangOptions;
-
 /// Available platforms for the availability attribute.
-enum class PlatformKind: uint8_t {
+enum class ENUM_EXTENSIBILITY_ATTR(closed) PlatformKind : uint8_t {
   none,
 #define AVAILABILITY_PLATFORM(X, PrettyName) X,
 #include "swift/AST/PlatformKinds.def"
 };
 
-/// Returns the short string representing the platform, suitable for
-/// use in availability specifications (e.g., "OSX").
-StringRef platformString(PlatformKind platform);
-  
-/// Returns the platform kind corresponding to the passed-in short platform name
-/// or None if such a platform kind does not exist.
-std::optional<PlatformKind> platformFromString(StringRef Name);
-
-/// Safely converts the given unsigned value to a valid \c PlatformKind value or
-/// \c nullopt otherwise.
-std::optional<PlatformKind> platformFromUnsigned(unsigned value);
-
-/// Returns a valid platform string that is closest to the candidate string
-/// based on edit distance. Returns \c None if the closest valid platform
-/// distance is not within a minimum threshold.
-std::optional<StringRef> closestCorrectedPlatformString(StringRef candidate);
-
-/// Returns a human-readable version of the platform name as a string, suitable
-/// for emission in diagnostics (e.g., "macOS").
-StringRef prettyPlatformString(PlatformKind platform);
-
-/// Returns the base platform for an application-extension platform. For example
-/// `iOS` would be returned for `iOSApplicationExtension`. Returns `None` for
-/// platforms which are not application extension platforms.
-std::optional<PlatformKind>
-basePlatformForExtensionPlatform(PlatformKind Platform);
-
-/// Returns true if \p Platform represents and application extension platform,
-/// e.g. `iOSApplicationExtension`.
-inline bool isApplicationExtensionPlatform(PlatformKind Platform) {
-  return basePlatformForExtensionPlatform(Platform).has_value();
-}
-
-/// Returns whether the passed-in platform is active, given the language
-/// options. A platform is active if either it is the target platform or its
-/// AppExtension variant is the target platform. For example, OS X is
-/// considered active when the target operating system is OS X and app extension
-/// restrictions are enabled, but OSXApplicationExtension is not considered
-/// active when the target platform is OS X and app extension restrictions are
-/// disabled. PlatformKind::none is always considered active.
-/// If ForTargetVariant is true then for zippered builds the target-variant
-/// triple will be used rather than the target to determine whether the
-/// platform is active.
-bool isPlatformActive(PlatformKind Platform, const LangOptions &LangOpts,
-                      bool ForTargetVariant = false, bool ForRuntimeQuery = false);
-
-/// Returns the target platform for the given language options.
-PlatformKind targetPlatform(const LangOptions &LangOpts);
-
-/// Returns the target variant platform for the given language options.
-PlatformKind targetVariantPlatform(const LangOptions &LangOpts);
-
-/// Returns true when availability attributes from the "parent" platform
-/// should also apply to the "child" platform for declarations without
-/// an explicit attribute for the child.
-bool inheritsAvailabilityFromPlatform(PlatformKind Child, PlatformKind Parent);
-
-llvm::VersionTuple canonicalizePlatformVersion(
-    PlatformKind platform, const llvm::VersionTuple &version);
-
-/// Returns true if \p Platform should be considered to be SPI and therefore not
-/// printed in public `.swiftinterface` files, for example.
-bool isPlatformSPI(PlatformKind Platform);
-
 } // end namespace swift
 
-#endif
+#endif // SWIFT_AST_PLATFORM_KIND_H
diff --git a/include/swift/AST/PlatformKindUtils.h b/include/swift/AST/PlatformKindUtils.h
new file mode 100644
index 0000000000000..e0f3f240a0e9e
--- /dev/null
+++ b/include/swift/AST/PlatformKindUtils.h
@@ -0,0 +1,101 @@
+//===--- AST/PlatformKindUtils.h --------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// This file declares operations for working with `PlatformKind`.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_AST_PLATFORM_KIND_UTILS_H
+#define SWIFT_AST_PLATFORM_KIND_UTILS_H
+
+#include "swift/AST/PlatformKind.h"
+#include "swift/Basic/LLVM.h"
+#include "swift/Config.h"
+#include "llvm/Support/VersionTuple.h"
+#include "llvm/TargetParser/Triple.h"
+#include <optional>
+
+namespace swift {
+
+class LangOptions;
+
+/// Returns the short string representing the platform, suitable for
+/// use in availability specifications (e.g., "OSX").
+StringRef platformString(PlatformKind platform);
+
+/// Returns the platform kind corresponding to the passed-in short platform name
+/// or None if such a platform kind does not exist.
+std::optional<PlatformKind> platformFromString(StringRef Name);
+
+/// Safely converts the given unsigned value to a valid \c PlatformKind value or
+/// \c nullopt otherwise.
+std::optional<PlatformKind> platformFromUnsigned(unsigned value);
+
+/// Returns a valid platform string that is closest to the candidate string
+/// based on edit distance. Returns \c None if the closest valid platform
+/// distance is not within a minimum threshold.
+std::optional<StringRef> closestCorrectedPlatformString(StringRef candidate);
+
+/// Returns a human-readable version of the platform name as a string, suitable
+/// for emission in diagnostics (e.g., "macOS").
+StringRef prettyPlatformString(PlatformKind platform);
+
+/// Returns the base platform for an application-extension platform. For example
+/// `iOS` would be returned for `iOSApplicationExtension`. Returns `None` for
+/// platforms which are not application extension platforms.
+std::optional<PlatformKind>
+basePlatformForExtensionPlatform(PlatformKind Platform);
+
+/// Returns true if \p Platform represents and application extension platform,
+/// e.g. `iOSApplicationExtension`.
+inline bool isApplicationExtensionPlatform(PlatformKind Platform) {
+  return basePlatformForExtensionPlatform(Platform).has_value();
+}
+
+/// Returns whether the passed-in platform is active, given the language
+/// options. A platform is active if either it is the target platform or its
+/// AppExtension variant is the target platform. For example, OS X is
+/// considered active when the target operating system is OS X and app extension
+/// restrictions are enabled, but OSXApplicationExtension is not considered
+/// active when the target platform is OS X and app extension restrictions are
+/// disabled. PlatformKind::none is always considered active.
+/// If ForTargetVariant is true then for zippered builds the target-variant
+/// triple will be used rather than the target to determine whether the
+/// platform is active.
+bool isPlatformActive(PlatformKind Platform, const LangOptions &LangOpts,
+                      bool ForTargetVariant = false, bool ForRuntimeQuery = false);
+
+/// Returns the target platform for the given language options.
+PlatformKind targetPlatform(const LangOptions &LangOpts);
+
+/// Returns the target variant platform for the given language options.
+PlatformKind targetVariantPlatform(const LangOptions &LangOpts);
+
+/// Returns true when availability attributes from the "parent" platform
+/// should also apply to the "child" platform for declarations without
+/// an explicit attribute for the child.
+bool inheritsAvailabilityFromPlatform(PlatformKind Child, PlatformKind Parent);
+
+/// Returns the LLVM triple OS type for the given platform, if there is one.
+std::optional<llvm::Triple::OSType>
+tripleOSTypeForPlatform(PlatformKind platform);
+
+llvm::VersionTuple canonicalizePlatformVersion(
+    PlatformKind platform, const llvm::VersionTuple &version);
+
+/// Returns true if \p Platform should be considered to be SPI and therefore not
+/// printed in public `.swiftinterface` files, for example.
+bool isPlatformSPI(PlatformKind Platform);
+
+} // end namespace swift
+
+#endif // SWIFT_AST_PLATFORM_KIND_UTILS_H
diff --git a/include/swift/AST/PlatformKinds.def b/include/swift/AST/PlatformKinds.def
index dd10bf495b65b..9b2fcdadd554a 100644
--- a/include/swift/AST/PlatformKinds.def
+++ b/include/swift/AST/PlatformKinds.def
@@ -34,6 +34,7 @@ AVAILABILITY_PLATFORM(visionOSApplicationExtension, "application extensions for
 AVAILABILITY_PLATFORM(macOSApplicationExtension, "application extensions for macOS")
 AVAILABILITY_PLATFORM(macCatalyst, "Mac Catalyst")
 AVAILABILITY_PLATFORM(macCatalystApplicationExtension, "application extensions for Mac Catalyst")
+AVAILABILITY_PLATFORM(FreeBSD, "FreeBSD")
 AVAILABILITY_PLATFORM(OpenBSD, "OpenBSD")
 AVAILABILITY_PLATFORM(Windows, "Windows")
 
diff --git a/include/swift/AST/PluginLoader.h b/include/swift/AST/PluginLoader.h
index fdcd73f13ba97..50f46a678d2fb 100644
--- a/include/swift/AST/PluginLoader.h
+++ b/include/swift/AST/PluginLoader.h
@@ -52,10 +52,18 @@ class PluginLoader {
   /// Get or lazily create and populate 'PluginMap'.
   llvm::DenseMap<swift::Identifier, PluginEntry> &getPluginMap();
 
+  /// Resolved plugin path remappings.
+  std::vector<std::pair<std::string, std::string>> PathRemap;
+
 public:
   PluginLoader(ASTContext &Ctx, DependencyTracker *DepTracker,
+               std::optional<std::vector<std::pair<std::string, std::string>>>
+                   Remap = std::nullopt,
                bool disableSandbox = false)
-      : Ctx(Ctx), DepTracker(DepTracker), disableSandbox(disableSandbox) {}
+      : Ctx(Ctx), DepTracker(DepTracker), disableSandbox(disableSandbox) {
+    if (Remap)
+      PathRemap = std::move(*Remap);
+  }
 
   void setRegistry(PluginRegistry *newValue);
   PluginRegistry *getRegistry();
diff --git a/include/swift/AST/PluginRegistry.h b/include/swift/AST/PluginRegistry.h
index f624a20b80d2d..02af09e0f808d 100644
--- a/include/swift/AST/PluginRegistry.h
+++ b/include/swift/AST/PluginRegistry.h
@@ -152,6 +152,9 @@ class LoadedExecutablePlugin : public CompilerPlugin {
         : process(process), input(input), output(output) {}
     ~PluginProcess();
 
+    PluginProcess(const PluginProcess &) = delete;
+    PluginProcess &operator=(const PluginProcess &) = delete;
+
     ssize_t write(const void *buf, size_t nbyte) const;
     ssize_t read(void *buf, size_t nbyte) const;
   };
diff --git a/include/swift/AST/PrintOptions.h b/include/swift/AST/PrintOptions.h
index 8c2773f282e71..504ef198311e4 100644
--- a/include/swift/AST/PrintOptions.h
+++ b/include/swift/AST/PrintOptions.h
@@ -16,9 +16,11 @@
 #include "swift/AST/AttrKind.h"
 #include "swift/AST/Identifier.h"
 #include "swift/AST/TypeOrExtensionDecl.h"
+#include "swift/Basic/OptionSet.h"
 #include "swift/Basic/STLExtras.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/STLExtras.h"
 #include <limits.h>
 #include <optional>
 #include <vector>
@@ -72,15 +74,15 @@ class BracketOptions {
                   CloseExtension(CloseExtension),
                   CloseNominal(CloseNominal) {}
 
-  bool shouldOpenExtension(const Decl *D) {
+  bool shouldOpenExtension(const Decl *D) const {
     return D != Target || OpenExtension;
   }
 
-  bool shouldCloseExtension(const Decl *D) {
+  bool shouldCloseExtension(const Decl *D) const {
     return D != Target || CloseExtension;
   }
 
-  bool shouldCloseNominal(const Decl *D) {
+  bool shouldCloseNominal(const Decl *D) const {
     return D != Target || CloseNominal;
   }
 };
@@ -123,11 +125,51 @@ struct ShouldPrintChecker {
   virtual ~ShouldPrintChecker() = default;
 };
 
+/// Type-printing options which should only be applied to the outermost
+/// type.
+enum class NonRecursivePrintOption: uint32_t {
+  /// Print `Optional<T>` as `T!`.
+  ImplicitlyUnwrappedOptional = 1 << 0,
+};
+using NonRecursivePrintOptions = OptionSet<NonRecursivePrintOption>;
+
 /// Options for printing AST nodes.
 ///
 /// A default-constructed PrintOptions is suitable for printing to users;
 /// there are also factory methods for specific use cases.
+///
+/// The value semantics of PrintOptions are a little messed up. We generally
+/// pass around options by const reference in order to (1) make it
+/// easier to pass in temporaries and (2) discourage direct local mutation
+/// in favor of the OverrideScope system below. However, that override
+/// system assumes that PrintOptions objects are always actually mutable.
 struct PrintOptions {
+
+  /// Explicitly copy these print options. You should generally aim to
+  /// avoid doing this, especially in deeply-embedded code, because
+  /// PrintOptions is a relatively heavyweight type (and is likely to
+  /// only get more heavyweight). Instead, try to use OverrideScope.
+  PrintOptions clone() const { return *this; }
+
+  /// Allow move construction and assignment. We don't expect to
+  /// actually use these much, but there isn't too much harm from
+  /// them.
+  PrintOptions(PrintOptions &&) = default;
+  PrintOptions &operator=(PrintOptions &&) = default;
+
+private:
+  /// Disallow implicit copying, but make it available privately for the
+  /// use of clone().
+  PrintOptions(const PrintOptions &) = default;
+
+  /// Disallow copy assignment completely, which we don't even need
+  /// privately.
+  PrintOptions &operator=(const PrintOptions &) = delete;
+
+public:
+  // defined later in this file
+  class OverrideScope;
+
   /// The indentation width.
   unsigned Indent = 2;
 
@@ -143,6 +185,9 @@ struct PrintOptions {
   /// Whether to print *any* accessors on properties.
   bool PrintPropertyAccessors = true;
 
+  /// Use \c let for a read-only computed property.
+  bool InferPropertyIntroducerFromAccessors = false;
+
   /// Whether to print *any* accessors on subscript.
   bool PrintSubscriptAccessors = true;
 
@@ -172,6 +217,10 @@ struct PrintOptions {
   /// Whether to print the bodies of accessors in protocol context.
   bool PrintAccessorBodiesInProtocols = false;
 
+  /// Whether to print the parameter list of accessors like \c set . (Even when
+  /// \c true , parameters marked implicit still won't be printed.)
+  bool PrintExplicitAccessorParameters = true;
+
   /// Whether to print type definitions.
   bool TypeDefinitions = false;
 
@@ -234,6 +283,12 @@ struct PrintOptions {
   /// \see FileUnit::getExportedModuleName
   bool UseExportedModuleNames = false;
 
+  /// If true, printed module names will use the "public" (for documentation)
+  /// name, which may be different from the regular name.
+  ///
+  /// \see FileUnit::getPublicModuleName
+  bool UsePublicModuleNames = false;
+
   /// Use the original module name to qualify a symbol.
   bool UseOriginallyDefinedInModuleNames = false;
 
@@ -345,9 +400,11 @@ struct PrintOptions {
   /// Whether to print the internal layout name instead of AnyObject, etc.
   bool PrintInternalLayoutName = false;
 
-  /// Suppress emitting isolated or async deinit, and emit open containing class
-  /// as public
-  bool SuppressIsolatedDeinit = false;
+  /// Suppress @_lifetime attribute and emit @lifetime instead.
+  bool SuppressLifetimes = false;
+
+  /// Suppress @inline(always) attribute and emit @inline(__always) instead.
+  bool SuppressInlineAlways = false;
 
   /// Whether to print the \c{/*not inherited*/} comment on factory initializers.
   bool PrintFactoryInitializerComment = true;
@@ -379,27 +436,15 @@ struct PrintOptions {
   /// Whether to suppress printing of custom attributes that are expanded macros.
   bool SuppressExpandedMacros = true;
 
-  /// Suppress the @isolated(any) attribute.
-  bool SuppressIsolatedAny = false;
-
   /// Suppress 'isolated' and '#isolation' on isolated parameters with optional type.
   bool SuppressOptionalIsolatedParams = false;
 
-  /// Suppress 'sending' on arguments and results.
-  bool SuppressSendingArgsAndResults = false;
-
   /// Suppress printing of '~Proto' for suppressible, non-invertible protocols.
   bool SuppressConformanceSuppression = false;
 
-  /// Replace BitwiseCopyable with _BitwiseCopyable.
-  bool SuppressBitwiseCopyable = false;
-
   /// Suppress modify/read accessors.
   bool SuppressCoroutineAccessors = false;
 
-  /// Suppress the @execution attribute
-  bool SuppressExecutionAttribute = false;
-
   /// List of attribute kinds that should not be printed.
   std::vector<AnyAttrKind> ExcludeAttrList = {
       DeclAttrKind::Transparent, DeclAttrKind::Effects,
@@ -540,13 +585,6 @@ struct PrintOptions {
   /// yet.
   llvm::SmallSet<StringRef, 4> *AliasModuleNamesTargets = nullptr;
 
-  /// When printing an Optional<T>, rather than printing 'T?', print
-  /// 'T!'. Used as a modifier only when we know we're printing
-  /// something that was declared as an implicitly unwrapped optional
-  /// at the top level. This is stripped out of the printing options
-  /// for optionals that are nested within other optionals.
-  bool PrintOptionalAsImplicitlyUnwrapped = false;
-
   /// Replaces the name of private and internal properties of types with '_'.
   bool OmitNameOfInaccessibleProperties = false;
 
@@ -591,7 +629,7 @@ struct PrintOptions {
   bool AlwaysDesugarArraySliceTypes = false;
 
   /// Whether to always desugar inline array types from
-  /// `[<count> x <element>]` to `InlineArray<count, element>`
+  /// `[<count> of <element>]` to `InlineArray<count, element>`
   bool AlwaysDesugarInlineArrayTypes = false;
 
   /// Whether to always desugar dictionary types
@@ -659,6 +697,13 @@ struct PrintOptions {
     return result;
   }
 
+  /// Print options suitable for debug printing.
+  static PrintOptions forDebugging() {
+    PrintOptions result;
+    result.PrintTypesForDebugging = true;
+    return result;
+  }
+
   /// Retrieve the set of options suitable for diagnostics printing.
   static PrintOptions printForDiagnostics(AccessLevel accessFilter,
                                           bool printFullConvention) {
@@ -707,6 +752,7 @@ struct PrintOptions {
     result.MapCrossImportOverlaysToDeclaringModule = true;
     result.PrintCurrentMembersOnly = false;
     result.SuppressExpandedMacros = true;
+    result.UsePublicModuleNames = true;
     return result;
   }
 
@@ -738,6 +784,8 @@ struct PrintOptions {
   void setBaseType(Type T);
 
   void initForSynthesizedExtension(TypeOrExtensionDecl D);
+  void initForSynthesizedExtensionInScope(TypeOrExtensionDecl D,
+                                          OverrideScope &scope) const;
 
   void clearSynthesizedExtension();
 
@@ -812,7 +860,87 @@ struct PrintOptions {
     PO.AlwaysTryPrintParameterLabels = true;
     return PO;
   }
+
+  /// An RAII scope for performing temporary adjustments to a PrintOptions
+  /// object. Even with the abstraction inherent in this design, this can
+  /// be significantly cheaper than copying the options just to modify a few
+  /// fields.
+  ///
+  /// At its core, this is just a stack of arbitrary functions to run
+  /// when the scope is destroyed.
+  class OverrideScope {
+  public:
+    /// The mutable options exposed by the scope. Generally, you should not
+    /// access this directly.
+    PrintOptions &Options;
+
+  private:
+    /// A stack of finalizer functions, each of which generally undoes some
+    /// change that was made to the options.
+    SmallVector<std::function<void(PrintOptions &)>, 4> Finalizers;
+
+  public:
+    OverrideScope(const PrintOptions &options)
+      : Options(const_cast<PrintOptions &>(options)) {}
+
+    // Disallow all copies and moves.
+    OverrideScope(const OverrideScope &scope) = delete;
+    OverrideScope &operator=(const OverrideScope &scope) = delete;
+
+    ~OverrideScope() {
+      // Run the finalizers in the opposite order that they were added.
+      for (auto &finalizer : llvm::reverse(Finalizers)) {
+        finalizer(Options);
+      }
+    }
+
+    template <class Fn>
+    void addFinalizer(Fn &&fn) {
+      Finalizers.emplace_back(std::move(fn));
+    }
+
+    void addExcludedAttr(AnyAttrKind kind) {
+      Options.ExcludeAttrList.push_back(kind);
+      addFinalizer([](PrintOptions &options) {
+        options.ExcludeAttrList.pop_back();
+      });
+    }
+  };
 };
-}
+
+/// Override a print option within an OverrideScope. Does a check to see if
+/// the new value is the same as the old before actually doing anything, so
+/// it only works if the type provides ==.
+///
+/// Signature is:
+///   void (OverrideScope &scope, <FIELD NAME>, T &&newValue)
+#define OVERRIDE_PRINT_OPTION(SCOPE, FIELD_NAME, VALUE)                     \
+  do {                                                                      \
+    auto _newValue = (VALUE);                                               \
+    if ((SCOPE).Options.FIELD_NAME != _newValue) {                          \
+      auto finalizer =                                                      \
+        [_oldValue=(SCOPE).Options.FIELD_NAME](PrintOptions &opts) {        \
+          opts.FIELD_NAME = _oldValue;                                      \
+        };                                                                  \
+      (SCOPE).Options.FIELD_NAME = std::move(_newValue);                    \
+      (SCOPE).addFinalizer(std::move(finalizer));                           \
+    }                                                                       \
+  } while(0)
+
+/// Override a print option within an OverrideScope. Works for any type.
+///
+/// Signature is:
+///   void (OverrideScope &scope, <FIELD NAME>, T &&newValue)
+#define OVERRIDE_PRINT_OPTION_UNCONDITIONAL(SCOPE, FIELD_NAME, VALUE)       \
+  do {                                                                      \
+    auto finalizer =                                                        \
+      [_oldValue=(SCOPE).Options.FIELD_NAME](PrintOptions &opts) {          \
+        opts.FIELD_NAME = _oldValue;                                        \
+      };                                                                    \
+    (SCOPE).Options.FIELD_NAME = (VALUE);                                   \
+    (SCOPE).addFinalizer(std::move(finalizer));                             \
+  } while(0)
+
+} // end namespace swift
 
 #endif // LLVM_SWIFT_AST_PRINTOPTIONS_H
diff --git a/include/swift/AST/ProtocolAssociations.h b/include/swift/AST/ProtocolAssociations.h
index 968dcb1f8bff5..c9589a367ef20 100644
--- a/include/swift/AST/ProtocolAssociations.h
+++ b/include/swift/AST/ProtocolAssociations.h
@@ -23,51 +23,6 @@
 
 namespace swift {
 
-/// A type associated with a protocol.
-///
-/// This struct exists largely so that we can maybe eventually
-/// generalize it to an arbitrary path.
-class AssociatedType {
-  AssociatedTypeDecl *Association;
-  using AssociationInfo = llvm::DenseMapInfo<AssociatedTypeDecl*>;
-
-  struct SpecialValue {};
-  explicit AssociatedType(SpecialValue _, AssociatedTypeDecl *specialValue)
-      : Association(specialValue) {}
-
-public:
-  explicit AssociatedType(AssociatedTypeDecl *association)
-      : Association(association) {
-    assert(association);
-  }
-
-  ProtocolDecl *getSourceProtocol() const {
-    return Association->getProtocol();
-  }
-
-  AssociatedTypeDecl *getAssociation() const {
-    return Association;
-  }
-
-  friend bool operator==(AssociatedType lhs, AssociatedType rhs) {
-    return lhs.Association == rhs.Association;
-  }
-  friend bool operator!=(AssociatedType lhs, AssociatedType rhs) {
-    return !(lhs == rhs);
-  }
-
-  unsigned getHashValue() const {
-    return llvm::hash_value(Association);
-  }
-
-  static AssociatedType getEmptyKey() {
-    return AssociatedType(SpecialValue(), AssociationInfo::getEmptyKey());
-  }
-  static AssociatedType getTombstoneKey() {
-    return AssociatedType(SpecialValue(), AssociationInfo::getTombstoneKey());
-  }
-};
-
 /// A base conformance of a protocol.
 class BaseConformance {
   ProtocolDecl *Source;
@@ -147,24 +102,6 @@ class AssociatedConformance {
 } // end namespace swift
 
 namespace llvm {
-  template <> struct DenseMapInfo<swift::AssociatedType> {
-    static inline swift::AssociatedType getEmptyKey() {
-      return swift::AssociatedType::getEmptyKey();
-    }
-
-    static inline swift::AssociatedType getTombstoneKey() {
-      return swift::AssociatedType::getTombstoneKey();
-    }
-
-    static unsigned getHashValue(swift::AssociatedType val) {
-      return val.getHashValue();
-    }
-
-    static bool isEqual(swift::AssociatedType lhs, swift::AssociatedType rhs) {
-      return lhs == rhs;
-    }
-  };
-
   template <> struct DenseMapInfo<swift::AssociatedConformance> {
     static inline swift::AssociatedConformance getEmptyKey() {
       return swift::AssociatedConformance::getEmptyKey();
diff --git a/include/swift/AST/ProtocolConformance.h b/include/swift/AST/ProtocolConformance.h
index a3981486bc1a9..70d6a71bbe91f 100644
--- a/include/swift/AST/ProtocolConformance.h
+++ b/include/swift/AST/ProtocolConformance.h
@@ -131,6 +131,9 @@ class alignas(1 << DeclAlignInBits) ProtocolConformance
   /// conformance definition.
   Type ConformingType;
 
+  friend class ConformanceIsolationRequest;
+  friend class RawConformanceIsolationRequest;
+
 protected:
   // clang-format off
   //
@@ -139,9 +142,16 @@ class alignas(1 << DeclAlignInBits) ProtocolConformance
   union { uint64_t OpaqueBits;
 
     SWIFT_INLINE_BITFIELD_BASE(ProtocolConformance,
+                               1+1+
                                bitmax(NumProtocolConformanceKindBits, 8),
       /// The kind of protocol conformance.
-      Kind : bitmax(NumProtocolConformanceKindBits, 8)
+      Kind : bitmax(NumProtocolConformanceKindBits, 8),
+
+      /// Whether the "raw" conformance isolation is "inferred", which applies to most conformances.
+      IsRawIsolationInferred : 1,
+
+      /// Whether the computed actor isolation is nonisolated.
+      IsComputedNonisolated : 1
     );
 
     SWIFT_INLINE_BITFIELD_EMPTY(RootProtocolConformance, ProtocolConformance);
@@ -161,9 +171,6 @@ class alignas(1 << DeclAlignInBits) ProtocolConformance
       /// this conformance.
       IsPreconcurrencyEffectful : 1,
 
-      /// Whether the computed actor isolation is nonisolated.
-      IsComputedNonisolated : 1,
-
       /// Whether there is an explicit global actor specified for this
       /// conformance.
       HasExplicitGlobalActor : 1,
@@ -198,6 +205,24 @@ class alignas(1 << DeclAlignInBits) ProtocolConformance
   ProtocolConformance(ProtocolConformanceKind kind, Type conformingType)
     : ConformingType(conformingType) {
     Bits.ProtocolConformance.Kind = unsigned(kind);
+    Bits.ProtocolConformance.IsRawIsolationInferred = false;
+    Bits.ProtocolConformance.IsComputedNonisolated = false;
+  }
+
+  bool isRawIsolationInferred() const {
+    return Bits.ProtocolConformance.IsRawIsolationInferred;
+  }
+
+  void setRawConformanceInferred(bool value = true) {
+    Bits.ProtocolConformance.IsRawIsolationInferred = value;
+  }
+
+  bool isComputedNonisolated() const {
+    return Bits.ProtocolConformance.IsComputedNonisolated;
+  }
+
+  void setComputedNonnisolated(bool value = true) {
+    Bits.ProtocolConformance.IsComputedNonisolated = value;
   }
 
 public:
@@ -246,6 +271,14 @@ class alignas(1 << DeclAlignInBits) ProtocolConformance
   /// Otherwise a new conformance will be created.
   ProtocolConformance *getCanonicalConformance();
 
+  /// Determine the "raw" actor isolation of this conformance, before applying any inference rules.
+  ///
+  /// Most clients should use `getIsolation()`, unless they are part of isolation inference
+  /// themselves (e.g., conformance checking).
+  ///
+  /// - Returns std::nullopt if the isolation will be inferred.
+  std::optional<ActorIsolation> getRawIsolation() const;
+
   /// Determine the actor isolation of this conformance.
   ActorIsolation getIsolation() const;
 
@@ -363,10 +396,6 @@ class alignas(1 << DeclAlignInBits) ProtocolConformance
   /// Retrieve the protocol conformance for the inherited protocol.
   ProtocolConformance *getInheritedConformance(ProtocolDecl *protocol) const;
 
-  /// Given a dependent type expressed in terms of the self parameter,
-  /// map it into the context of this conformance.
-  Type getAssociatedType(Type assocType) const;
-
   /// Given that the requirement signature of the protocol directly states
   /// that the given dependent type must conform to the given protocol,
   /// return its associated conformance.
@@ -544,6 +573,7 @@ class NormalProtocolConformance : public RootProtocolConformance,
   friend class ValueWitnessRequest;
   friend class TypeWitnessRequest;
   friend class ConformanceIsolationRequest;
+  friend class RawConformanceIsolationRequest;
 
   /// The protocol being conformed to.
   ProtocolDecl *Protocol;
@@ -552,10 +582,17 @@ class NormalProtocolConformance : public RootProtocolConformance,
   SourceLoc Loc;
 
   /// The location of the protocol name within the conformance.
+  ///
+  /// - Important: This is not a valid insertion location for an attribute.
+  /// Use `applyConformanceAttribute` instead.
   SourceLoc ProtocolNameLoc;
 
-  /// The location of the `@preconcurrency` attribute, if any.
-  SourceLoc PreconcurrencyLoc;
+  /// The `TypeRepr` of the inheritance clause entry that declares this
+  /// conformance, if any. For example, if this is a conformance to `Y`
+  /// declared as `struct S: X, Y & Z {}`, this is the `TypeRepr` for `Y & Z`.
+  ///
+  /// - Important: The value can be valid only for an explicit conformance.
+  TypeRepr *inheritedTypeRepr;
 
   /// The declaration context containing the ExtensionDecl or
   /// NominalTypeDecl that declared the conformance.
@@ -591,30 +628,26 @@ class NormalProtocolConformance : public RootProtocolConformance,
   // Record the explicitly-specified global actor isolation.
   void setExplicitGlobalActorIsolation(TypeExpr *typeExpr);
 
-  bool isComputedNonisolated() const {
-    return Bits.NormalProtocolConformance.IsComputedNonisolated;
-  }
-
-  void setComputedNonnisolated(bool value = true) {
-    Bits.NormalProtocolConformance.IsComputedNonisolated = value;
-  }
+  /// Return the `TypeRepr` of the inheritance clause entry that declares this
+  /// conformance, if any. For example, if this is a conformance to `Y`
+  /// declared as `struct S: X, Y & Z {}`, this is the `TypeRepr` for `Y & Z`.
+  ///
+  /// - Important: The value can be valid only for an explicit conformance.
+  TypeRepr *getInheritedTypeRepr() const { return inheritedTypeRepr; }
 
 public:
   NormalProtocolConformance(Type conformingType, ProtocolDecl *protocol,
-                            SourceLoc loc, DeclContext *dc,
-                            ProtocolConformanceState state,
-                            ProtocolConformanceOptions options,
-                            SourceLoc preconcurrencyLoc)
+                            SourceLoc loc, TypeRepr *inheritedTypeRepr,
+                            DeclContext *dc, ProtocolConformanceState state,
+                            ProtocolConformanceOptions options)
       : RootProtocolConformance(ProtocolConformanceKind::Normal,
                                 conformingType),
         Protocol(protocol), Loc(extractNearestSourceLoc(dc)),
-        ProtocolNameLoc(loc), PreconcurrencyLoc(preconcurrencyLoc),
+        ProtocolNameLoc(loc), inheritedTypeRepr(inheritedTypeRepr),
         Context(dc) {
     assert(!conformingType->hasArchetype() &&
            "ProtocolConformances should store interface types");
-    assert((preconcurrencyLoc.isInvalid() ||
-            options.contains(ProtocolConformanceFlags::Preconcurrency)) &&
-           "Cannot have a @preconcurrency location without isPreconcurrency");
+
     setState(state);
     Bits.NormalProtocolConformance.IsInvalid = false;
     Bits.NormalProtocolConformance.IsPreconcurrencyEffectful = false;
@@ -622,9 +655,11 @@ class NormalProtocolConformance : public RootProtocolConformance,
     Bits.NormalProtocolConformance.HasComputedAssociatedConformances = false;
     Bits.NormalProtocolConformance.SourceKind =
         unsigned(ConformanceEntryKind::Explicit);
-    Bits.NormalProtocolConformance.IsComputedNonisolated = false;
     Bits.NormalProtocolConformance.HasExplicitGlobalActor = false;
     setExplicitGlobalActorIsolation(options.getGlobalActorIsolationType());
+
+    assert((!getPreconcurrencyLoc() || isPreconcurrency()) &&
+           "Cannot have a @preconcurrency location without isPreconcurrency");
   }
 
   /// Get the protocol being conformed to.
@@ -634,6 +669,9 @@ class NormalProtocolConformance : public RootProtocolConformance,
   SourceLoc getLoc() const { return Loc; }
 
   /// Retrieve the name of the protocol location.
+  ///
+  /// - Important: This is not a valid insertion location for an attribute.
+  ///   Use `applyConformanceAttribute` instead.
   SourceLoc getProtocolNameLoc() const { return ProtocolNameLoc; }
 
   /// Get the declaration context that contains the conforming extension or
@@ -704,7 +742,9 @@ class NormalProtocolConformance : public RootProtocolConformance,
 
   /// Retrieve the location of `@preconcurrency`, if there is one and it is
   /// known.
-  SourceLoc getPreconcurrencyLoc() const { return PreconcurrencyLoc; }
+  ///
+  /// - Important: The value can be valid only for an explicit conformance.
+  SourceLoc getPreconcurrencyLoc() const;
 
   /// Query whether this conformance was explicitly declared to be safe or
   /// unsafe.
@@ -714,6 +754,9 @@ class NormalProtocolConformance : public RootProtocolConformance,
     return ExplicitSafety::Unspecified;
   }
 
+  /// Whether this conformance has explicitly-specified global actor isolation.
+  bool hasExplicitGlobalActorIsolation() const;
+
   /// Determine whether we've lazily computed the associated conformance array
   /// already.
   bool hasComputedAssociatedConformances() const {
@@ -825,6 +868,15 @@ class NormalProtocolConformance : public RootProtocolConformance,
   /// Triggers a request that resolves all of the conformance's value witnesses.
   void resolveValueWitnesses() const;
 
+  /// If the necessary source location information is found, attaches a fix-it
+  /// to the given diagnostic for applying the given attribute to the
+  /// conformance.
+  ///
+  /// \param attrStr A conformance attribute as a string, e.g. "@unsafe" or
+  /// "nonisolated".
+  void applyConformanceAttribute(InFlightDiagnostic &diag,
+                                 std::string attrStr) const;
+
   /// Determine whether the witness for the given type requirement
   /// is the default definition.
   bool usesDefaultDefinition(AssociatedTypeDecl *requirement) const {
@@ -916,9 +968,7 @@ class SelfProtocolConformance : public RootProtocolConformance {
   }
 
   ProtocolConformanceRef getAssociatedConformance(Type assocType,
-                                                  ProtocolDecl *protocol) const{
-    llvm_unreachable("self-conformances never have associated types");
-  }
+                                                  ProtocolDecl *protocol) const;
 
   bool hasWitness(ValueDecl *requirement) const {
     return true;
diff --git a/include/swift/AST/ProtocolConformanceRef.h b/include/swift/AST/ProtocolConformanceRef.h
index 5267e03c9d8d0..f7fde1e87b8a1 100644
--- a/include/swift/AST/ProtocolConformanceRef.h
+++ b/include/swift/AST/ProtocolConformanceRef.h
@@ -120,27 +120,26 @@ class ProtocolConformanceRef {
                                             ProtocolDecl *protocol);
 
   bool isConcrete() const {
-    return !isInvalid() && Union.is<ProtocolConformance*>();
+    return !isInvalid() && isa<ProtocolConformance *>(Union);
   }
   ProtocolConformance *getConcrete() const {
     ASSERT(isConcrete());
-    return Union.get<ProtocolConformance*>();
+    return cast<ProtocolConformance *>(Union);
   }
 
-  bool isPack() const {
-    return !isInvalid() && Union.is<PackConformance*>();
-  }
+  bool isPack() const { return !isInvalid() && isa<PackConformance *>(Union); }
   PackConformance *getPack() const {
     ASSERT(isPack());
-    return Union.get<PackConformance*>();
+    return cast<PackConformance *>(Union);
   }
 
   bool isAbstract() const {
-    return !isInvalid() && Union.is<AbstractConformance*>();
+    return !isInvalid() && isa<AbstractConformance *>(Union);
   }
 
   AbstractConformance *getAbstract() const {
-    return Union.get<AbstractConformance *>();
+    ASSERT(isAbstract());
+    return cast<AbstractConformance *>(Union);
   }
 
   /// Determine whether this conformance (or a conformance it depends on)
@@ -185,11 +184,11 @@ class ProtocolConformanceRef {
   ProtocolDecl *getProtocol() const;
   
   /// Apply a substitution to the conforming type.
-  ProtocolConformanceRef subst(Type origType, SubstitutionMap subMap,
+  ProtocolConformanceRef subst(SubstitutionMap subMap,
                                SubstOptions options = std::nullopt) const;
 
   /// Apply a substitution to the conforming type.
-  ProtocolConformanceRef subst(Type origType, TypeSubstitutionFn subs,
+  ProtocolConformanceRef subst(TypeSubstitutionFn subs,
                                LookupConformanceFn conformances,
                                SubstOptions options = std::nullopt) const;
 
@@ -197,26 +196,24 @@ class ProtocolConformanceRef {
   ///
   /// This function should generally not be used outside of the substitution
   /// subsystem.
-  ProtocolConformanceRef subst(Type origType,
-                               InFlightSubstitution &IFS) const;
+  ProtocolConformanceRef subst(InFlightSubstitution &IFS) const;
 
   /// Map contextual types to interface types in the conformance.
   ProtocolConformanceRef mapConformanceOutOfContext() const;
 
   /// Look up the type witness for an associated type declaration in this
   /// conformance.
-  Type getTypeWitness(Type origType, AssociatedTypeDecl *assocType,
+  Type getTypeWitness(AssociatedTypeDecl *assocType,
                       SubstOptions options = std::nullopt) const;
 
   /// Given a dependent type (expressed in terms of this conformance's
   /// protocol), follow it from the conforming type.
-  Type getAssociatedType(Type origType, Type dependentType) const;
+  Type getAssociatedType(Type dependentType) const;
 
   /// Given a dependent type (expressed in terms of this conformance's
   /// protocol) and conformance, follow it from the conforming type.
   ProtocolConformanceRef
-  getAssociatedConformance(Type origType, Type dependentType,
-                           ProtocolDecl *requirement) const;
+  getAssociatedConformance(Type dependentType, ProtocolDecl *requirement) const;
 
   SWIFT_DEBUG_DUMP;
   void dump(llvm::raw_ostream &out, unsigned indent = 0,
@@ -235,7 +232,7 @@ class ProtocolConformanceRef {
     return llvm::hash_value(conformance.Union.getOpaqueValue());
   }
 
-  Type getTypeWitnessByName(Type type, Identifier name) const;
+  Type getTypeWitnessByName(Identifier name) const;
 
   /// Find a particular named function witness for a type that conforms to
   /// the given protocol.
@@ -243,7 +240,7 @@ class ProtocolConformanceRef {
   /// \param type The conforming type.
   ///
   /// \param name The name of the requirement.
-  ConcreteDeclRef getWitnessByName(Type type, DeclName name) const;
+  ConcreteDeclRef getWitnessByName(DeclName name) const;
 
   /// Determine whether this conformance is canonical.
   bool isCanonical() const;
diff --git a/include/swift/AST/RequirementEnvironment.h b/include/swift/AST/RequirementEnvironment.h
index a0ce72a59ca94..282e7e4da26b8 100644
--- a/include/swift/AST/RequirementEnvironment.h
+++ b/include/swift/AST/RequirementEnvironment.h
@@ -114,7 +114,8 @@ class RequirementEnvironment {
   }
 
   /// Retrieve the substitution map that maps the interface types of the
-  /// requirement to the interface types of the witness thunk signature.
+  /// requirement to the archetypes of the witness thunk signature's
+  /// generic environment.
   SubstitutionMap getRequirementToWitnessThunkSubs() const {
     return reqToWitnessThunkSigMap;
   }
diff --git a/include/swift/AST/RequirementMatch.h b/include/swift/AST/RequirementMatch.h
index 1130be03d9502..31326d6a72e2a 100644
--- a/include/swift/AST/RequirementMatch.h
+++ b/include/swift/AST/RequirementMatch.h
@@ -12,6 +12,7 @@
 #ifndef SWIFT_AST_REQUIREMENTMATCH_H
 #define SWIFT_AST_REQUIREMENTMATCH_H
 
+#include "swift/AST/AvailabilityConstraint.h"
 #include "swift/AST/RequirementEnvironment.h"
 #include "swift/AST/Type.h"
 #include "swift/AST/Types.h"
@@ -217,10 +218,6 @@ enum class CheckKind : unsigned {
   /// The witness is less accessible than the requirement.
   Access,
 
-  /// The witness is storage whose setter is less accessible than the
-  /// requirement.
-  AccessOfSetter,
-
   /// The witness needs to be @usableFromInline.
   UsableFromInline,
 
@@ -228,7 +225,7 @@ enum class CheckKind : unsigned {
   Availability,
 
   /// The requirement was marked explicitly unavailable.
-  Unavailable,
+  RequirementUnavailable,
 
   /// The witness requires optional adjustments.
   OptionalityConflict,
@@ -237,39 +234,81 @@ enum class CheckKind : unsigned {
   /// requirement.
   ConstructorFailability,
 
-  /// The witness itself is inaccessible.
-  WitnessUnavailable,
-
   /// The witness is a deprecated default implementation provided by the
   /// protocol.
   DefaultWitnessDeprecated,
 };
+
 /// Describes the suitability of the chosen witness for
 /// the requirement.
-struct RequirementCheck {
+class RequirementCheck {
   CheckKind Kind;
 
-  /// The required access scope, if the check failed due to the
-  /// witness being less accessible than the requirement.
-  AccessScope RequiredAccessScope;
+  union {
+    /// Storage for `CheckKind::Access`.
+    struct {
+      AccessScope requiredScope;
+      bool forSetter;
+    } Access;
+
+    /// Storage for `CheckKind::Availability`.
+    struct {
+      AvailabilityConstraint constraint;
+      AvailabilityContext requiredContext;
+    } Availability;
+  };
 
-  /// The required availability, if the check failed due to the
-  /// witness being less available than the requirement.
-  AvailabilityRange RequiredAvailability;
+public:
+  RequirementCheck(CheckKind kind) : Kind(kind) {
+    // These kinds have their own constructors.
+    ASSERT(kind != CheckKind::Access);
+    ASSERT(kind != CheckKind::Availability);
+  }
 
-  RequirementCheck(CheckKind kind)
-      : Kind(kind), RequiredAccessScope(AccessScope::getPublic()),
-        RequiredAvailability(AvailabilityRange::alwaysAvailable()) {}
+  RequirementCheck(AccessScope requiredAccessScope, bool forSetter)
+      : Kind(CheckKind::Access), Access{requiredAccessScope, forSetter} {}
 
-  RequirementCheck(CheckKind kind, AccessScope requiredAccessScope)
-      : Kind(kind), RequiredAccessScope(requiredAccessScope),
-        RequiredAvailability(AvailabilityRange::alwaysAvailable()) {}
+  RequirementCheck(AvailabilityConstraint constraint,
+                   AvailabilityContext requiredContext)
+      : Kind(CheckKind::Availability),
+        Availability{constraint, requiredContext} {}
 
-  RequirementCheck(CheckKind kind, AvailabilityRange requiredAvailability)
-      : Kind(kind), RequiredAccessScope(AccessScope::getPublic()),
-        RequiredAvailability(requiredAvailability) {}
-};
+  CheckKind getKind() const { return Kind; }
 
+  /// True if the witness is storage whose setter is less accessible than the
+  /// requirement.
+  bool isForSetterAccess() const {
+    return (Kind == CheckKind::Access) ? Access.forSetter : false;
+  }
+
+  /// True if the witness is less available than the requirement.
+  bool isLessAvailable() const {
+    return (Kind == CheckKind::Availability)
+               ? !Availability.constraint.isUnavailable()
+               : false;
+  }
+
+  /// The required access scope for checks that failed due to the witness being
+  /// less accessible than the requirement.
+  AccessScope getRequiredAccessScope() const {
+    ASSERT(Kind == CheckKind::Access);
+    return Access.requiredScope;
+  }
+
+  /// The availability constraint that would fail if the witness were accessed
+  /// from contexts in which the requirement is available.
+  AvailabilityConstraint getAvailabilityConstraint() const {
+    ASSERT(Kind == CheckKind::Availability);
+    return Availability.constraint;
+  }
+
+  /// The required availability range for checks that failed due to the witness
+  /// being less available than the requirement.
+  AvailabilityContext getRequiredAvailabilityContext() const {
+    ASSERT(Kind == CheckKind::Availability);
+    return Availability.requiredContext;
+  }
+};
 
 /// Describes a match between a requirement and a witness.
 struct RequirementMatch {
diff --git a/include/swift/AST/RuntimeVersions.def b/include/swift/AST/RuntimeVersions.def
index 6a5c8918f8160..39d0a279c6f28 100644
--- a/include/swift/AST/RuntimeVersions.def
+++ b/include/swift/AST/RuntimeVersions.def
@@ -152,11 +152,22 @@ RUNTIME_VERSION(
 
 RUNTIME_VERSION(
   (6, 1),
-  FUTURE
+  PLATFORM(macOS,   (15, 4, 0))
+  PLATFORM(iOS,     (18, 4, 0))
+  PLATFORM(watchOS, (11, 4, 0))
+  PLATFORM(visionOS,(2, 4, 0))
 )
 
 RUNTIME_VERSION(
   (6, 2),
+  PLATFORM(macOS,   (26, 0, 0))
+  PLATFORM(iOS,     (26, 0, 0))
+  PLATFORM(watchOS, (26, 0, 0))
+  PLATFORM(visionOS,(26, 0, 0))
+)
+
+RUNTIME_VERSION(
+  (6, 3),
   FUTURE
 )
 
diff --git a/include/swift/AST/SILLayout.h b/include/swift/AST/SILLayout.h
index 1b5267bd7b33d..63c486e579263 100644
--- a/include/swift/AST/SILLayout.h
+++ b/include/swift/AST/SILLayout.h
@@ -141,10 +141,8 @@ class SILLayout final : public llvm::FoldingSetNode,
   }
   
   /// Get the fields inside the layout.
-  ArrayRef<SILField> getFields() const {
-    return llvm::ArrayRef(getTrailingObjects<SILField>(), NumFields);
-  }
-  
+  ArrayRef<SILField> getFields() const { return getTrailingObjects(NumFields); }
+
   /// Produce a profile of this layout, for use in a folding set.
   static void Profile(llvm::FoldingSetNodeID &id,
                       CanGenericSignature Generics,
diff --git a/include/swift/AST/SILOptions.h b/include/swift/AST/SILOptions.h
index 2c18a09d21823..da8e88772a59d 100644
--- a/include/swift/AST/SILOptions.h
+++ b/include/swift/AST/SILOptions.h
@@ -45,14 +45,17 @@ enum class CopyPropagationOption : uint8_t {
   // Do not add any copy propagation passes.
   Off = 0,
 
-  // Only add the copy propagation passes requested by other flags, currently
-  // just -enable-ossa-modules.
+  // Only add the copy propagation passes requested by other flags.
   RequestedPassesOnly,
 
-  // Add all relevant copy propagation passes.  If a setting, e.g.
-  // -enable-ossa-modules, requests to add copy propagation to the pipeline, do
-  // so.
-  On
+  // Run copy propagation during optimized builds only.
+  //
+  // If a setting, requests to add copy propagation
+  // to the performance pipeline, do so.
+  Optimizing,
+
+  // Run copy propagation during all builds and whenever requested.
+  Always
 };
 
 enum class DestroyHoistingOption : uint8_t {
@@ -90,11 +93,8 @@ class SILOptions {
   /// observable end of lexical scope.
   LexicalLifetimesOption LexicalLifetimes = LexicalLifetimesOption::On;
 
-  /// Whether to run SIL copy propagation to shorten object lifetime in whatever
-  /// optimization pipeline is currently used.
-  ///
-  /// When this is 'On' the pipeline has default behavior.
-  CopyPropagationOption CopyPropagation = CopyPropagationOption::On;
+  /// Controls when to run SIL copy propagation, which shortens object lifetimes
+  CopyPropagationOption CopyPropagation = CopyPropagationOption::Optimizing;
 
   /// Whether to run the DestroyAddrHoisting pass.
   ///
@@ -188,11 +188,6 @@ class SILOptions {
   /// and go from OSSA to non-ownership SIL.
   bool StopOptimizationBeforeLoweringOwnership = false;
 
-  /// Do we always serialize SIL in OSSA form?
-  ///
-  /// If this is disabled we do not serialize in OSSA form when optimizing.
-  bool EnableOSSAModules = true;
-
   /// Allow recompilation of a non-OSSA module to an OSSA module when imported
   /// from another OSSA module.
   bool EnableRecompilationToOSSAModule = false;
@@ -308,14 +303,14 @@ class SILOptions {
   /// Are we building in embedded Swift + -no-allocations?
   bool NoAllocations = false;
 
-  /// Should we use the experimental Swift based closure-specialization
-  /// optimization pass instead of the existing C++ one.
-  bool EnableExperimentalSwiftBasedClosureSpecialization = false;
-
   /// The name of the file to which the backend should save optimization
   /// records.
   std::string OptRecordFile;
 
+  /// The names of the auxiliar files to which the backend should save optimization
+  /// records for the remaining (other than the main one) LLVMModules.
+  std::vector<std::string> AuxOptRecordFiles;
+
   /// The regex that filters the passes that should be saved to the optimization
   /// records.
   std::string OptRecordPasses;
@@ -323,6 +318,9 @@ class SILOptions {
   /// The format used for serializing remarks (default: YAML)
   llvm::remarks::Format OptRecordFormat = llvm::remarks::Format::YAML;
 
+  /// Whether to apply _assemblyVision to all functions.
+  bool EnableGlobalAssemblyVision = false;
+
   /// Are there any options that indicate that functions should not be preserved
   /// for the debugger?
   bool ShouldFunctionsBePreservedToDebugger = true;
@@ -338,6 +336,10 @@ class SILOptions {
   // Whether to allow merging traps and cond_fails.
   bool MergeableTraps = false;
 
+  /// Whether the @yield_once_2 convention is used by accessors added with the
+  /// CoroutineAccessors feature (i.e. read2/modify2).
+  bool CoroutineAccessorsUseYieldOnce2 = false;
+
   SILOptions() {}
 
   /// Return a hash code of any components from these options that should
diff --git a/include/swift/AST/SearchPathOptions.h b/include/swift/AST/SearchPathOptions.h
index ff697f5ef49b4..f8101fe93db68 100644
--- a/include/swift/AST/SearchPathOptions.h
+++ b/include/swift/AST/SearchPathOptions.h
@@ -35,7 +35,7 @@ namespace swift {
 enum class ModuleSearchPathKind {
   Import,
   Framework,
-  DarwinImplicitFramework,
+  ImplicitFramework,
   RuntimeLibrary,
 };
 
@@ -323,6 +323,10 @@ class SearchPathOptions {
     friend bool operator!=(const SearchPath &LHS, const SearchPath &RHS) {
       return !(LHS == RHS);
     }
+    friend llvm::hash_code
+    hash_value(const SearchPath &searchPath) {
+      return llvm::hash_combine(searchPath.Path, searchPath.IsSystem);
+    }
   };
 
 private:
@@ -352,12 +356,8 @@ class SearchPathOptions {
   /// When on Darwin the framework paths that are implicitly imported.
   /// $SDKROOT/System/Library/Frameworks/ and $SDKROOT/Library/Frameworks/.
   ///
-  /// On non-Darwin platforms these are populated, but ignored.
-  ///
-  /// Computed when the SDK path is set and cached so we can reference the
-  /// Darwin implicit framework search paths as \c StringRef from
-  /// \c ModuleSearchPath.
-  std::vector<std::string> DarwinImplicitFrameworkSearchPaths;
+  /// Must be modified through setter to keep \c Lookup in sync.
+  std::vector<std::string> ImplicitFrameworkSearchPaths;
 
   /// Compiler plugin library search paths.
   std::vector<std::string> CompilerPluginLibraryPaths;
@@ -397,21 +397,6 @@ class SearchPathOptions {
 
   void setSDKPath(std::string NewSDKPath) {
     SDKPath = NewSDKPath;
-
-    // Compute Darwin implicit framework search paths.
-    SmallString<128> systemFrameworksScratch(NewSDKPath);
-    llvm::sys::path::append(systemFrameworksScratch, "System", "Library",
-                            "Frameworks");
-    SmallString<128> systemSubFrameworksScratch(NewSDKPath);
-    llvm::sys::path::append(systemSubFrameworksScratch, "System", "Library",
-                            "SubFrameworks");
-    SmallString<128> frameworksScratch(NewSDKPath);
-    llvm::sys::path::append(frameworksScratch, "Library", "Frameworks");
-    DarwinImplicitFrameworkSearchPaths = {systemFrameworksScratch.str().str(),
-                                          systemSubFrameworksScratch.str().str(),
-                                          frameworksScratch.str().str()};
-
-    Lookup.searchPathsDidChange();
   }
 
   /// Retrieves the corresponding parent platform path for the SDK, or
@@ -466,8 +451,14 @@ class SearchPathOptions {
 
   /// The extra implicit framework search paths on Apple platforms:
   /// $SDKROOT/System/Library/Frameworks/ and $SDKROOT/Library/Frameworks/.
-  ArrayRef<std::string> getDarwinImplicitFrameworkSearchPaths() const {
-    return DarwinImplicitFrameworkSearchPaths;
+  ArrayRef<std::string> getImplicitFrameworkSearchPaths() const {
+    return ImplicitFrameworkSearchPaths;
+  }
+
+  void setImplicitFrameworkSearchPaths(
+      std::vector<std::string> NewImplicitFrameworkSearchPaths) {
+    ImplicitFrameworkSearchPaths = NewImplicitFrameworkSearchPaths;
+    Lookup.searchPathsDidChange();
   }
 
   ArrayRef<std::string> getRuntimeLibraryImportPaths() const {
@@ -501,14 +492,17 @@ class SearchPathOptions {
   /// Path to in-process plugin server shared library.
   std::string InProcessPluginServerPath;
 
-  /// Don't look in for compiler-provided modules.
-  bool SkipRuntimeLibraryImportPaths = false;
+  /// Don't automatically add any import paths.
+  bool SkipAllImplicitImportPaths = false;
 
-  /// Don't include SDK paths in the RuntimeLibraryImportPaths
-  bool ExcludeSDKPathsFromRuntimeLibraryImportPaths = false;
+  /// Don't automatically add any import paths from the SDK.
+  bool SkipSDKImportPaths = false;
 
   /// Scanner Prefix Mapper.
-  std::vector<std::string> ScannerPrefixMapper;
+  std::vector<std::pair<std::string, std::string>> ScannerPrefixMapper;
+
+  /// Verify resolved plugin is not changed.
+  bool ResolvedPluginVerification = false;
 
   /// When set, don't validate module system dependencies.
   ///
@@ -524,11 +518,8 @@ class SearchPathOptions {
   std::string ExplicitSwiftModuleMapPath;
 
   /// Module inputs specified with -swift-module-input,
-  /// <ModuleName, Path to .swiftmodule file>
-  std::vector<std::pair<std::string, std::string>> ExplicitSwiftModuleInputs;
-
-  /// A map of placeholder Swift module dependency information.
-  std::string PlaceholderDependencyModuleMap;
+  /// ModuleName: Path to .swiftmodule file
+  llvm::StringMap<std::string> ExplicitSwiftModuleInputs;
 
   /// A file containing a list of protocols whose conformances require const value extraction.
   std::string ConstGatherProtocolListFilePath;
@@ -596,35 +587,24 @@ class SearchPathOptions {
   makeOverlayFileSystem(
       llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS) const;
 
-private:
-  static StringRef pathStringFromSearchPath(const SearchPath &next) {
-    return next.Path;
-  };
-
 public:
   /// Return a hash code of any components from these options that should
   /// contribute to a Swift Bridging PCH hash.
   llvm::hash_code getPCHHashComponents() const {
     using llvm::hash_combine;
     using llvm::hash_combine_range;
-
-    using SearchPathView =
-        ArrayRefView<SearchPath, StringRef, pathStringFromSearchPath>;
-    SearchPathView importPathsOnly{ImportSearchPaths};
-    SearchPathView frameworkPathsOnly{FrameworkSearchPaths};
-
     return hash_combine(SDKPath,
-                        // FIXME: Should we include the system-ness of
-                        // search paths too?
-                        hash_combine_range(importPathsOnly.begin(), importPathsOnly.end()),
+                        hash_combine_range(ImportSearchPaths.begin(), ImportSearchPaths.end()),
                         hash_combine_range(VFSOverlayFiles.begin(), VFSOverlayFiles.end()),
-                        hash_combine_range(frameworkPathsOnly.begin(),
-                                           frameworkPathsOnly.end()),
+                        hash_combine_range(FrameworkSearchPaths.begin(),
+                                           FrameworkSearchPaths.end()),
                         hash_combine_range(LibrarySearchPaths.begin(),
                                            LibrarySearchPaths.end()),
                         RuntimeResourcePath,
                         hash_combine_range(RuntimeLibraryImportPaths.begin(),
                                            RuntimeLibraryImportPaths.end()),
+                        hash_combine_range(ImplicitFrameworkSearchPaths.begin(),
+                                           ImplicitFrameworkSearchPaths.end()),
                         DisableModulesValidateSystemDependencies,
                         ScannerModuleValidation,
                         ModuleLoadMode);
diff --git a/include/swift/AST/SemanticAttrs.def b/include/swift/AST/SemanticAttrs.def
index f2b93fb575ffe..98ada5ecb7a2e 100644
--- a/include/swift/AST/SemanticAttrs.def
+++ b/include/swift/AST/SemanticAttrs.def
@@ -73,6 +73,8 @@ SEMANTICS_ATTR(OPTIMIZE_SIL_SPECIALIZE_GENERIC_PARTIAL_NEVER,
           "optimize.sil.specialize.generic.partial.never")
 SEMANTICS_ATTR(OPTIMIZE_SIL_INLINE_CONSTANT_ARGUMENTS,
           "optimize.sil.inline.constant.arguments")
+SEMANTICS_ATTR(DERIVED_ENUM_EQUALS,
+          "derived_enum_equals")
 SEMANTICS_ATTR(OPTIMIZE_SIL_SPECIALIZE_GENERIC_SIZE_NEVER,
           "optimize.sil.specialize.generic.size.never")
 SEMANTICS_ATTR(OPTIMIZE_SIL_SPECIALIZE_OWNED2GUARANTEE_NEVER,
@@ -165,5 +167,7 @@ SEMANTICS_ATTR(USE_FRAME_POINTER, "use_frame_pointer")
 SEMANTICS_ATTR(FIXED_STORAGE_CHECK_INDEX, "fixed_storage.check_index")
 SEMANTICS_ATTR(FIXED_STORAGE_GET_COUNT, "fixed_storage.get_count")
 
+SEMANTICS_ATTR(NO_SIL_VERIFICATION, "sil.verify_none")
+
 #undef SEMANTICS_ATTR
 
diff --git a/include/swift/AST/SourceFile.h b/include/swift/AST/SourceFile.h
index b154007d7e864..a4f663c2eea99 100644
--- a/include/swift/AST/SourceFile.h
+++ b/include/swift/AST/SourceFile.h
@@ -28,9 +28,11 @@
 namespace swift {
 class ASTScope;
 class AvailabilityScope;
+class GeneratedSourceInfo;
 class PersistentParserState;
 struct SourceFileExtras;
 class Token;
+enum class DefaultIsolation : uint8_t;
 
 /// Kind of import affecting how a decl can be reexported.
 ///
@@ -53,15 +55,6 @@ enum class RestrictedImportKind {
 /// Import that limits the access level of imported entities.
 using ImportAccessLevel = std::optional<AttributedImport<ImportedModule>>;
 
-/// Language options only for use with a specific SourceFile.
-///
-/// Vended by SourceFile::getLanguageOptions().
-struct SourceFileLangOptions {
-  /// If unset, no value was provided. If a Type, that type is the type of the
-  /// isolation. If set to an empty type, nil was specified explicitly.
-  std::optional<Type> defaultIsolation;
-};
-
 /// A file containing Swift source code.
 ///
 /// This is a .swift or .sil file (or a virtual file, such as the contents of
@@ -144,8 +137,8 @@ class SourceFile final : public FileUnit {
 
   /// Associates a list of source locations to the member declarations that must
   /// be diagnosed as being out of scope due to a missing import.
-  using DelayedMissingImportForMemberDiags =
-      llvm::SmallDenseMap<const ValueDecl *, std::vector<SourceLoc>>;
+  using DelayedMissingImportForMemberDiags = llvm::SmallDenseMap<
+      const ValueDecl *, std::vector<std::pair<SourceLoc, DiagnosticBehavior>>>;
   DelayedMissingImportForMemberDiags MissingImportForMemberDiagnostics;
 
   /// A unique identifier representing this file; used to mark private decls
@@ -478,6 +471,11 @@ class SourceFile final : public FileUnit {
                 const ModuleDecl *importedModule,
                 llvm::SmallSetVector<Identifier, 4> &spiGroups) const override;
 
+  /// Returns true if any import of \p importedModule has the `@preconcurrency`
+  /// attribute.
+  virtual bool isModuleImportedPreconcurrency(
+      const ModuleDecl *importedModule) const override;
+
   // Is \p targetDecl accessible as an explicitly imported SPI from this file?
   bool isImportedAsSPI(const ValueDecl *targetDecl) const;
 
@@ -525,8 +523,9 @@ class SourceFile final : public FileUnit {
   /// Add a source location for which a delayed missing import for member
   /// diagnostic should be emited.
   void addDelayedMissingImportForMemberDiagnostic(const ValueDecl *decl,
-                                                  SourceLoc loc) {
-    MissingImportForMemberDiagnostics[decl].push_back(loc);
+                                                  SourceLoc loc,
+                                                  DiagnosticBehavior limit) {
+    MissingImportForMemberDiagnostics[decl].push_back({loc, limit});
   }
 
   DelayedMissingImportForMemberDiags
@@ -571,9 +570,6 @@ class SourceFile final : public FileUnit {
          ObjCSelector selector,
          SmallVectorImpl<AbstractFunctionDecl *> &results) const override;
 
-  /// File level language options.
-  SourceFileLangOptions getLanguageOptions() const;
-
 protected:
   virtual void
   lookupOperatorDirect(Identifier name, OperatorFixity fixity,
@@ -701,6 +697,11 @@ class SourceFile final : public FileUnit {
     DelayedParserState = std::move(state);
   }
 
+  /// Retrieve default action isolation to be used for this source file.
+  /// It's determine based on on top-level `using <<isolation>>` declaration
+  /// found in the file.
+  std::optional<DefaultIsolation> getDefaultIsolation() const;
+
   SWIFT_DEBUG_DUMP;
   void
   dump(raw_ostream &os,
diff --git a/include/swift/AST/Stmt.h b/include/swift/AST/Stmt.h
index 0682f73e5bcb1..50238fef5fc39 100644
--- a/include/swift/AST/Stmt.h
+++ b/include/swift/AST/Stmt.h
@@ -19,6 +19,7 @@
 
 #include "swift/AST/ASTAllocated.h"
 #include "swift/AST/ASTNode.h"
+#include "swift/AST/AvailabilityQuery.h"
 #include "swift/AST/AvailabilityRange.h"
 #include "swift/AST/ConcreteDeclRef.h"
 #include "swift/AST/IfConfigClause.h"
@@ -83,8 +84,9 @@ class alignas(8) Stmt : public ASTAllocated<Stmt> {
     NumElements : 32
   );
 
-  SWIFT_INLINE_BITFIELD_FULL(CaseStmt, Stmt, 32,
+  SWIFT_INLINE_BITFIELD_FULL(CaseStmt, Stmt, 16+32,
     : NumPadBits,
+    NumCaseBodyVars : 16,
     NumPatterns : 32
   );
 
@@ -213,16 +215,20 @@ class BraceStmt final : public Stmt,
 
   /// The elements contained within the BraceStmt.
   MutableArrayRef<ASTNode> getElements() {
-    return {getTrailingObjects<ASTNode>(), static_cast<size_t>(Bits.BraceStmt.NumElements)};
+    return getTrailingObjects(static_cast<size_t>(Bits.BraceStmt.NumElements));
   }
 
   /// The elements contained within the BraceStmt (const version).
   ArrayRef<ASTNode> getElements() const {
-    return {getTrailingObjects<ASTNode>(), static_cast<size_t>(Bits.BraceStmt.NumElements)};
+    return getTrailingObjects(static_cast<size_t>(Bits.BraceStmt.NumElements));
   }
 
   ASTNode findAsyncNode();
 
+  /// Whether the body contains an explicit `return` statement. This computation
+  /// is cached.
+  bool hasExplicitReturnStmt(ASTContext &ctx) const;
+
   /// If this brace contains a single ASTNode, or a \c #if that has a single active
   /// element, returns it. This will always be the last element of the brace.
   /// Otherwise returns \c nullptr.
@@ -331,10 +337,10 @@ class YieldStmt final
   SourceLoc getEndLoc() const;
 
   ArrayRef<Expr*> getYields() const {
-    return {getTrailingObjects<Expr*>(), static_cast<size_t>(Bits.YieldStmt.NumYields)};
+    return getTrailingObjects(static_cast<size_t>(Bits.YieldStmt.NumYields));
   }
   MutableArrayRef<Expr*> getMutableYields() {
-    return {getTrailingObjects<Expr*>(), static_cast<size_t>(Bits.YieldStmt.NumYields)};
+    return getTrailingObjects(static_cast<size_t>(Bits.YieldStmt.NumYields));
   }
   
   static bool classof(const Stmt *S) { return S->getKind() == StmtKind::Yield; }
@@ -477,20 +483,11 @@ class alignas(8) PoundAvailableInfo final :
   SourceLoc LParenLoc;
   SourceLoc RParenLoc;
 
-  // The number of queries tail allocated after this object.
+  /// The number of queries tail allocated after this object.
   unsigned NumQueries;
-  
-  /// The version range when this query will return true. This value is
-  /// filled in by Sema.
-  std::optional<VersionRange> AvailableRange;
-
-  /// For zippered builds, this is the version range for the target variant
-  /// that must hold for the query to return true. For example, when
-  /// compiling with target x86_64-macosx10.15 and target-variant
-  /// x86_64-ios13.0 a query of #available(macOS 10.22, iOS 20.0, *) will
-  /// have a variant range of [20.0, +inf).
-  /// This is filled in by Sema.
-  std::optional<VersionRange> VariantAvailableRange;
+
+  /// The type-checked availability query information.
+  std::optional<const AvailabilityQuery> Query;
 
   struct {
     unsigned isInvalid : 1;
@@ -504,12 +501,11 @@ class alignas(8) PoundAvailableInfo final :
                      ArrayRef<AvailabilitySpec *> queries, SourceLoc RParenLoc,
                      bool isUnavailability)
       : PoundLoc(PoundLoc), LParenLoc(LParenLoc), RParenLoc(RParenLoc),
-        NumQueries(queries.size()), AvailableRange(VersionRange::empty()),
-        VariantAvailableRange(VersionRange::empty()), Flags() {
+        NumQueries(queries.size()), Flags() {
     Flags.isInvalid = false;
     Flags.isUnavailability = isUnavailability;
     std::uninitialized_copy(queries.begin(), queries.end(),
-                            getTrailingObjects<AvailabilitySpec *>());
+                            getTrailingObjects());
   }
 
 public:
@@ -523,7 +519,7 @@ class alignas(8) PoundAvailableInfo final :
   void setInvalid() { Flags.isInvalid = true; }
 
   ArrayRef<AvailabilitySpec *> getQueries() const {
-    return llvm::ArrayRef(getTrailingObjects<AvailabilitySpec *>(), NumQueries);
+    return getTrailingObjects(NumQueries);
   }
 
   /// Returns an iterator for the statement's type-checked availability specs.
@@ -539,16 +535,11 @@ class alignas(8) PoundAvailableInfo final :
   SourceRange getSourceRange() const { return SourceRange(getStartLoc(),
                                                           getEndLoc()); }
 
-  std::optional<VersionRange> getAvailableRange() const {
-    return AvailableRange;
+  std::optional<const AvailabilityQuery> getAvailabilityQuery() const {
+    return Query;
   }
-  void setAvailableRange(const VersionRange &Range) { AvailableRange = Range; }
-
-  std::optional<VersionRange> getVariantAvailableRange() const {
-    return VariantAvailableRange;
-  }
-  void setVariantAvailableRange(const VersionRange &Range) {
-    VariantAvailableRange = Range;
+  void setAvailabilityQuery(const AvailabilityQuery &query) {
+    Query.emplace(query);
   }
 
   bool isUnavailability() const { return Flags.isUnavailability; }
@@ -640,13 +631,13 @@ class alignas(1 << PatternAlignInBits) StmtConditionElement {
   };
 
   ConditionKind getKind() const {
-    if (Condition.is<Expr *>())
+    if (isa<Expr *>(Condition))
       return CK_Boolean;
-    if (Condition.is<ConditionalPatternBindingInfo *>())
+    if (isa<ConditionalPatternBindingInfo *>(Condition))
       return CK_PatternBinding;
-    if (Condition.is<PoundAvailableInfo *>())
+    if (isa<PoundAvailableInfo *>(Condition))
       return CK_Availability;
-    if (Condition.is<PoundHasSymbolInfo *>())
+    if (isa<PoundHasSymbolInfo *>(Condition))
       return CK_HasSymbol;
     return CK_Boolean;
   }
@@ -656,7 +647,7 @@ class alignas(1 << PatternAlignInBits) StmtConditionElement {
 
   Expr *getBoolean() const {
     assert(getKind() == CK_Boolean && "Not a condition");
-    return Condition.get<Expr *>();
+    return cast<Expr *>(Condition);
   }
   void setBoolean(Expr *E) {
     assert(getKind() == CK_Boolean && "Not a condition");
@@ -670,7 +661,7 @@ class alignas(1 << PatternAlignInBits) StmtConditionElement {
 
   ConditionalPatternBindingInfo *getPatternBinding() const {
     assert(getKind() == CK_PatternBinding && "Not a pattern binding condition");
-    return Condition.get<ConditionalPatternBindingInfo *>();
+    return cast<ConditionalPatternBindingInfo *>(Condition);
   }
 
   SourceLoc getIntroducerLoc() const {
@@ -704,7 +695,7 @@ class alignas(1 << PatternAlignInBits) StmtConditionElement {
   // Availability Accessors
   PoundAvailableInfo *getAvailability() const {
     assert(getKind() == CK_Availability && "Not an #available condition");
-    return Condition.get<PoundAvailableInfo *>();
+    return cast<PoundAvailableInfo *>(Condition);
   }
 
   void setAvailability(PoundAvailableInfo *Info) {
@@ -715,7 +706,7 @@ class alignas(1 << PatternAlignInBits) StmtConditionElement {
   // #_hasSymbol Accessors
   PoundHasSymbolInfo *getHasSymbolInfo() const {
     assert(getKind() == CK_HasSymbol && "Not a #_hasSymbol condition");
-    return Condition.get<PoundHasSymbolInfo *>();
+    return cast<PoundHasSymbolInfo *>(Condition);
   }
 
   void setHasSymbolInfo(PoundHasSymbolInfo *Info) {
@@ -729,6 +720,8 @@ class alignas(1 << PatternAlignInBits) StmtConditionElement {
   ///    RHS of the self condition references a var defined in a capture list.
   ///  - If `requireLoadExpr` is `true`, additionally requires that the RHS of
   ///    the self condition is a `LoadExpr`.
+  /// TODO: Remove `requireLoadExpr` after full-on of the ImmutableWeakCaptures
+  /// feature
   bool rebindsSelf(ASTContext &Ctx, bool requiresCaptureListRef = false,
                    bool requireLoadExpr = false) const;
 
@@ -839,8 +832,6 @@ class LabeledConditionalStmt : public LabeledStmt {
   /// or `let self = self` condition.
   ///  - If `requiresCaptureListRef` is `true`, additionally requires that the
   ///    RHS of the self condition references a var defined in a capture list.
-  ///  - If `requireLoadExpr` is `true`, additionally requires that the RHS of
-  ///    the self condition is a `LoadExpr`.
   bool rebindsSelf(ASTContext &Ctx, bool requiresCaptureListRef = false,
                    bool requireLoadExpr = false) const;
 
@@ -1224,8 +1215,8 @@ enum CaseParentKind { Switch, DoCatch };
 ///
 class CaseStmt final
     : public Stmt,
-      private llvm::TrailingObjects<CaseStmt, FallthroughStmt *,
-                                    CaseLabelItem> {
+      private llvm::TrailingObjects<CaseStmt, FallthroughStmt *, CaseLabelItem,
+                                    VarDecl *> {
   friend TrailingObjects;
 
   Stmt *ParentStmt = nullptr;
@@ -1236,15 +1227,17 @@ class CaseStmt final
 
   llvm::PointerIntPair<BraceStmt *, 1, bool> BodyAndHasFallthrough;
 
-  std::optional<MutableArrayRef<VarDecl *>> CaseBodyVariables;
-
   CaseStmt(CaseParentKind ParentKind, SourceLoc ItemIntroducerLoc,
            ArrayRef<CaseLabelItem> CaseLabelItems, SourceLoc UnknownAttrLoc,
            SourceLoc ItemTerminatorLoc, BraceStmt *Body,
-           std::optional<MutableArrayRef<VarDecl *>> CaseBodyVariables,
-           std::optional<bool> Implicit,
+           ArrayRef<VarDecl *> CaseBodyVariables, std::optional<bool> Implicit,
            NullablePtr<FallthroughStmt> fallthroughStmt);
 
+  MutableArrayRef<VarDecl *> getCaseBodyVariablesBuffer() {
+    return {getTrailingObjects<VarDecl *>(),
+            static_cast<size_t>(Bits.CaseStmt.NumCaseBodyVars)};
+  }
+
 public:
   /// Create a parsed 'case'/'default' for 'switch' statement.
   static CaseStmt *
@@ -1258,13 +1251,17 @@ class CaseStmt final
                                        ArrayRef<CaseLabelItem> CaseLabelItems,
                                        BraceStmt *Body);
 
+  static CaseStmt *
+  createImplicit(ASTContext &ctx, CaseParentKind parentKind,
+                 ArrayRef<CaseLabelItem> caseLabelItems, BraceStmt *body,
+                 NullablePtr<FallthroughStmt> fallthroughStmt = nullptr);
+
   static CaseStmt *
   create(ASTContext &C, CaseParentKind ParentKind, SourceLoc ItemIntroducerLoc,
          ArrayRef<CaseLabelItem> CaseLabelItems, SourceLoc UnknownAttrLoc,
          SourceLoc ItemTerminatorLoc, BraceStmt *Body,
-         std::optional<MutableArrayRef<VarDecl *>> CaseBodyVariables,
-         std::optional<bool> Implicit = std::nullopt,
-         NullablePtr<FallthroughStmt> fallthroughStmt = nullptr);
+         ArrayRef<VarDecl *> CaseBodyVariables, std::optional<bool> Implicit,
+         NullablePtr<FallthroughStmt> fallthroughStmt);
 
   CaseParentKind getParentKind() const { return ParentKind; }
 
@@ -1307,7 +1304,7 @@ class CaseStmt final
   void setBody(BraceStmt *body) { BodyAndHasFallthrough.setPointer(body); }
 
   /// True if the case block declares any patterns with local variable bindings.
-  bool hasBoundDecls() const { return CaseBodyVariables.has_value(); }
+  bool hasCaseBodyVariables() const { return !getCaseBodyVariables().empty(); }
 
   /// Get the source location of the 'case', 'default', or 'catch' of the first
   /// label.
@@ -1359,38 +1356,8 @@ class CaseStmt final
   }
 
   /// Return an ArrayRef containing the case body variables of this CaseStmt.
-  ///
-  /// Asserts if case body variables was not explicitly initialized. In contexts
-  /// where one wants a non-asserting version, \see
-  /// getCaseBodyVariablesOrEmptyArray.
   ArrayRef<VarDecl *> getCaseBodyVariables() const {
-    ArrayRef<VarDecl *> a = *CaseBodyVariables;
-    return a;
-  }
-
-  bool hasCaseBodyVariables() const { return CaseBodyVariables.has_value(); }
-
-  /// Return an MutableArrayRef containing the case body variables of this
-  /// CaseStmt.
-  ///
-  /// Asserts if case body variables was not explicitly initialized. In contexts
-  /// where one wants a non-asserting version, \see
-  /// getCaseBodyVariablesOrEmptyArray.
-  MutableArrayRef<VarDecl *> getCaseBodyVariables() {
-    return *CaseBodyVariables;
-  }
-
-  ArrayRef<VarDecl *> getCaseBodyVariablesOrEmptyArray() const {
-    if (!CaseBodyVariables)
-      return ArrayRef<VarDecl *>();
-    ArrayRef<VarDecl *> a = *CaseBodyVariables;
-    return a;
-  }
-
-  MutableArrayRef<VarDecl *> getCaseBodyVariablesOrEmptyArray() {
-    if (!CaseBodyVariables)
-      return MutableArrayRef<VarDecl *>();
-    return *CaseBodyVariables;
+    return const_cast<CaseStmt *>(this)->getCaseBodyVariablesBuffer();
   }
 
   /// Find the next case statement within the same 'switch' or 'do-catch',
@@ -1464,8 +1431,7 @@ class SwitchStmt final : public LabeledStmt,
 
   /// Get the list of case clauses.
   ArrayRef<CaseStmt *> getCases() const {
-    return {getTrailingObjects<CaseStmt *>(),
-            static_cast<size_t>(Bits.SwitchStmt.CaseCount)};
+    return getTrailingObjects(static_cast<size_t>(Bits.SwitchStmt.CaseCount));
   }
 
   /// Retrieve the complete set of branches for this switch statement.
@@ -1505,7 +1471,7 @@ class DoCatchStmt final
         Body(body) {
     Bits.DoCatchStmt.NumCatches = catches.size();
     std::uninitialized_copy(catches.begin(), catches.end(),
-                            getTrailingObjects<CaseStmt *>());
+                            getTrailingObjects());
     for (auto *catchStmt : getCatches())
       catchStmt->setParentStmt(this);
   }
@@ -1539,10 +1505,10 @@ class DoCatchStmt final
   void setBody(Stmt *s) { Body = s; }
 
   ArrayRef<CaseStmt *> getCatches() const {
-    return {getTrailingObjects<CaseStmt *>(), static_cast<size_t>(Bits.DoCatchStmt.NumCatches)};
+    return getTrailingObjects(static_cast<size_t>(Bits.DoCatchStmt.NumCatches));
   }
   MutableArrayRef<CaseStmt *> getMutableCatches() {
-    return {getTrailingObjects<CaseStmt *>(), static_cast<size_t>(Bits.DoCatchStmt.NumCatches)};
+    return getTrailingObjects(static_cast<size_t>(Bits.DoCatchStmt.NumCatches));
   }
 
   /// Retrieve the complete set of branches for this do-catch statement.
diff --git a/include/swift/AST/StorageImpl.h b/include/swift/AST/StorageImpl.h
index 6f94f504207eb..64cf4f5b17a01 100644
--- a/include/swift/AST/StorageImpl.h
+++ b/include/swift/AST/StorageImpl.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -18,6 +18,7 @@
 #ifndef SWIFT_STORAGEIMPL_H
 #define SWIFT_STORAGEIMPL_H
 
+#include "swift/AST/AccessorKind.h"
 #include "swift/Basic/Range.h"
 #include "llvm/ADT/StringRef.h"
 
@@ -47,16 +48,6 @@ enum class OpaqueReadOwnership : uint8_t {
   OwnedOrBorrowed
 };
 
-// Note that the values of these enums line up with %select values in
-// diagnostics.
-enum class AccessorKind {
-#define ACCESSOR(ID) ID,
-#define LAST_ACCESSOR(ID) Last = ID
-#include "swift/AST/AccessorKinds.def"
-#undef ACCESSOR
-#undef LAST_ACCESSOR
-};
-
 inline bool requiresFeatureCoroutineAccessors(AccessorKind kind) {
   switch (kind) {
   case AccessorKind::Read2:
@@ -71,6 +62,29 @@ inline bool requiresFeatureCoroutineAccessors(AccessorKind kind) {
   case AccessorKind::DidSet:
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
+  case AccessorKind::Init:
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
+    return false;
+  }
+}
+
+inline bool requiresFeatureBorrowAndMutateAccessors(AccessorKind kind) {
+  switch (kind) {
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
+    return true;
+  case AccessorKind::Get:
+  case AccessorKind::DistributedGet:
+  case AccessorKind::Set:
+  case AccessorKind::Read:
+  case AccessorKind::Read2:
+  case AccessorKind::Modify:
+  case AccessorKind::Modify2:
+  case AccessorKind::WillSet:
+  case AccessorKind::DidSet:
+  case AccessorKind::Address:
+  case AccessorKind::MutableAddress:
   case AccessorKind::Init:
     return false;
   }
@@ -91,6 +105,8 @@ inline bool isYieldingAccessor(AccessorKind kind) {
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
   case AccessorKind::Init:
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
     return false;
   }
 }
@@ -110,6 +126,8 @@ inline bool isYieldingImmutableAccessor(AccessorKind kind) {
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
   case AccessorKind::Init:
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
     return false;
   }
 }
@@ -129,6 +147,8 @@ inline bool isYieldingMutableAccessor(AccessorKind kind) {
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
   case AccessorKind::Init:
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
     return false;
   }
 }
@@ -144,7 +164,7 @@ static inline IntRange<AccessorKind> allAccessorKinds() {
 static inline llvm::StringRef accessorKindName(AccessorKind ak) {
   switch(ak) {
 
-#define ACCESSOR(ID) ID
+#define ACCESSOR(ID, KEYWORD) ID
 #define SINGLETON_ACCESSOR(ID, KEYWORD)                                        \
   case AccessorKind::ID:                                                       \
     return #KEYWORD;
@@ -287,6 +307,9 @@ enum class ReadImplKind {
 
   /// There's a read coroutine.
   Read2,
+
+  /// There's a borrow accessor.
+  Borrow,
 };
 enum { NumReadImplKindBits = 4 };
 
@@ -316,6 +339,9 @@ enum class WriteImplKind {
 
   /// There's a modify coroutine.
   Modify2,
+
+  /// There's a mutate accessor.
+  Mutate,
 };
 enum { NumWriteImplKindBits = 4 };
 
@@ -344,6 +370,9 @@ enum class ReadWriteImplKind {
   // access pattern.
   StoredWithDidSet,
   InheritedWithDidSet,
+
+  /// There's a mutate accessor.
+  Mutate,
 };
 enum { NumReadWriteImplKindBits = 4 };
 
@@ -397,34 +426,45 @@ class StorageImplInfo {
       return;
 
     case WriteImplKind::Set:
-      assert(readImpl == ReadImplKind::Get ||
-             readImpl == ReadImplKind::Address ||
-             readImpl == ReadImplKind::Read || readImpl == ReadImplKind::Read2);
+      assert(
+          readImpl == ReadImplKind::Get || readImpl == ReadImplKind::Address ||
+          readImpl == ReadImplKind::Read || readImpl == ReadImplKind::Read2 ||
+          readImpl == ReadImplKind::Borrow);
       assert(readWriteImpl == ReadWriteImplKind::MaterializeToTemporary ||
              readWriteImpl == ReadWriteImplKind::Modify ||
              readWriteImpl == ReadWriteImplKind::Modify2);
       return;
 
     case WriteImplKind::Modify:
-      assert(readImpl == ReadImplKind::Get ||
-             readImpl == ReadImplKind::Address ||
-             readImpl == ReadImplKind::Read || readImpl == ReadImplKind::Read2);
+      assert(
+          readImpl == ReadImplKind::Get || readImpl == ReadImplKind::Address ||
+          readImpl == ReadImplKind::Read || readImpl == ReadImplKind::Read2 ||
+          readImpl == ReadImplKind::Borrow);
       assert(readWriteImpl == ReadWriteImplKind::Modify);
       return;
 
     case WriteImplKind::Modify2:
-      assert(readImpl == ReadImplKind::Get ||
-             readImpl == ReadImplKind::Address ||
-             readImpl == ReadImplKind::Read || readImpl == ReadImplKind::Read2);
+      assert(
+          readImpl == ReadImplKind::Get || readImpl == ReadImplKind::Address ||
+          readImpl == ReadImplKind::Read || readImpl == ReadImplKind::Read2 ||
+          readImpl == ReadImplKind::Borrow);
       assert(readWriteImpl == ReadWriteImplKind::Modify2);
       return;
 
     case WriteImplKind::MutableAddress:
-      assert(readImpl == ReadImplKind::Get ||
-             readImpl == ReadImplKind::Address ||
-             readImpl == ReadImplKind::Read || readImpl == ReadImplKind::Read2);
+      assert(
+          readImpl == ReadImplKind::Get || readImpl == ReadImplKind::Address ||
+          readImpl == ReadImplKind::Read || readImpl == ReadImplKind::Read2 ||
+          readImpl == ReadImplKind::Borrow);
       assert(readWriteImpl == ReadWriteImplKind::MutableAddress);
       return;
+    case WriteImplKind::Mutate:
+      assert(
+          readImpl == ReadImplKind::Get || readImpl == ReadImplKind::Address ||
+          readImpl == ReadImplKind::Read || readImpl == ReadImplKind::Read2 ||
+          readImpl == ReadImplKind::Borrow);
+      assert(readWriteImpl == ReadWriteImplKind::Mutate);
+      return;
     }
     llvm_unreachable("bad write impl kind");
 #endif
diff --git a/include/swift/AST/SubstitutionMap.h b/include/swift/AST/SubstitutionMap.h
index 961d87d87bcd7..868d59ef265b7 100644
--- a/include/swift/AST/SubstitutionMap.h
+++ b/include/swift/AST/SubstitutionMap.h
@@ -181,11 +181,9 @@ class SubstitutionMap {
   /// subsystem.
   SubstitutionMap subst(InFlightSubstitution &subs) const;
 
-  /// Apply type expansion lowering to all types in the substitution map. Opaque
-  /// archetypes will be lowered to their underlying types if the type expansion
-  /// context allows.
-  SubstitutionMap mapIntoTypeExpansionContext(
-      TypeExpansionContext context) const;
+  /// Create a substitution map for a protocol conformance.
+  static SubstitutionMap
+  getProtocolSubstitutions(ProtocolConformanceRef conformance);
 
   /// Create a substitution map for a protocol conformance.
   static SubstitutionMap
@@ -219,7 +217,7 @@ class SubstitutionMap {
 
   /// Whether to dump the full substitution map, or just a minimal useful subset
   /// (on a single line).
-  enum class DumpStyle { Minimal, Full };
+  enum class DumpStyle { Minimal, NoConformances, Full };
   /// Dump the contents of this substitution map for debugging purposes.
   void dump(llvm::raw_ostream &out, DumpStyle style = DumpStyle::Full,
             unsigned indent = 0) const;
@@ -296,13 +294,12 @@ class LookUpConformanceInSubstitutionMap {
   explicit LookUpConformanceInSubstitutionMap(SubstitutionMap Subs)
     : Subs(Subs) {}
 
-  ProtocolConformanceRef operator()(CanType dependentType,
-                                    Type conformingReplacementType,
-                                    ProtocolDecl *conformedProtocol) const;
+  ProtocolConformanceRef operator()(InFlightSubstitution &IFS,
+                                    Type dependentType,
+                                    ProtocolDecl *proto) const;
 };
 
 struct OverrideSubsInfo {
-  ASTContext &Ctx;
   unsigned BaseDepth;
   unsigned OrigDepth;
   SubstitutionMap BaseSubMap;
@@ -329,8 +326,8 @@ struct LookUpConformanceInOverrideSubs {
   explicit LookUpConformanceInOverrideSubs(const OverrideSubsInfo &info)
     : info(info) {}
 
-  ProtocolConformanceRef operator()(CanType type,
-                                    Type substType,
+  ProtocolConformanceRef operator()(InFlightSubstitution &IFS,
+                                    Type dependentType,
                                     ProtocolDecl *proto) const;
 };
 
@@ -340,11 +337,10 @@ struct OuterSubstitutions {
   SubstitutionMap subs;
   unsigned depth;
 
-  bool isUnsubstitutedTypeParameter(Type type) const;
   Type operator()(SubstitutableType *type) const;
-  ProtocolConformanceRef operator()(CanType dependentType,
-                                    Type conformingReplacementType,
-                                    ProtocolDecl *conformedProtocol) const;
+  ProtocolConformanceRef operator()(InFlightSubstitution &IFS,
+                                    Type dependentType,
+                                    ProtocolDecl *proto) const;
 };
 
 } // end namespace swift
diff --git a/include/swift/AST/SwiftNameTranslation.h b/include/swift/AST/SwiftNameTranslation.h
index 3e3c880643197..1ae3f691fccd9 100644
--- a/include/swift/AST/SwiftNameTranslation.h
+++ b/include/swift/AST/SwiftNameTranslation.h
@@ -13,6 +13,7 @@
 #ifndef SWIFT_NAME_TRANSLATION_H
 #define SWIFT_NAME_TRANSLATION_H
 
+#include "swift/AST/ASTContext.h"
 #include "swift/AST/AttrKind.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/DiagnosticEngine.h"
@@ -112,6 +113,9 @@ inline bool isExposableToCxx(
   return !getDeclRepresentation(VD, isZeroSized).isUnsupported();
 }
 
+bool isObjCxxOnly(const ValueDecl *VD);
+bool isObjCxxOnly(const clang::Decl *D, const ASTContext &ctx);
+
 /// Returns true if the given value decl D is visible to C++ of its
 /// own accord (i.e. without considering its context)
 bool isVisibleToCxx(const ValueDecl *VD, AccessLevel minRequiredAccess,
diff --git a/include/swift/AST/Type.h b/include/swift/AST/Type.h
index 7591f14e8520e..8d6a849fb3010 100644
--- a/include/swift/AST/Type.h
+++ b/include/swift/AST/Type.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -26,6 +26,7 @@
 #include "swift/Basic/ArrayRefView.h"
 #include "swift/Basic/Compiler.h"
 #include "swift/Basic/Debug.h"
+#include "swift/Basic/InlineBitfield.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/OptionSet.h"
 #include "llvm/ADT/DenseMap.h"
@@ -88,9 +89,9 @@ struct QueryTypeSubstitutionMap {
 };
 
 /// Function used to resolve conformances.
-using GenericFunction = auto(CanType dependentType,
-                             Type conformingReplacementType,
-                             ProtocolDecl *conformedProtocol)
+using GenericFunction = auto(InFlightSubstitution &IFS,
+                             Type dependentType,
+                             ProtocolDecl *proto)
                             -> ProtocolConformanceRef;
 using LookupConformanceFn = llvm::function_ref<GenericFunction>;
   
@@ -100,19 +101,9 @@ class LookUpConformanceInModule {
 public:
   explicit LookUpConformanceInModule() {}
 
-  ProtocolConformanceRef operator()(CanType dependentType,
-                                    Type conformingReplacementType,
-                                    ProtocolDecl *conformedProtocol) const;
-};
-
-/// Functor class suitable for use as a \c LookupConformanceFn that provides
-/// only abstract conformances for generic types. Asserts that the replacement
-/// type is an opaque generic type.
-class MakeAbstractConformanceForGenericType {
-public:
-  ProtocolConformanceRef operator()(CanType dependentType,
-                                    Type conformingReplacementType,
-                                    ProtocolDecl *conformedProtocol) const;
+  ProtocolConformanceRef operator()(InFlightSubstitution &IFS,
+                                    Type dependentType,
+                                    ProtocolDecl *proto) const;
 };
   
 /// Flags that can be passed when substituting into a type.
@@ -161,7 +152,7 @@ inline SubstOptions operator|(SubstFlags lhs, SubstFlags rhs) {
 
 /// Enumeration describing foreign languages to which Swift may be
 /// bridged.
-enum class ForeignLanguage {
+enum class ForeignLanguage : uint8_t {
   C,
   ObjectiveC,
 };
@@ -347,11 +338,14 @@ class Type {
   SWIFT_DEBUG_DUMP;
   void dump(raw_ostream &os, unsigned indent = 0) const;
 
-  void print(raw_ostream &OS, const PrintOptions &PO = PrintOptions()) const;
-  void print(ASTPrinter &Printer, const PrintOptions &PO) const;
+  void print(raw_ostream &OS, const PrintOptions &PO = PrintOptions(),
+             NonRecursivePrintOptions OPO = std::nullopt) const;
+  void print(ASTPrinter &Printer, const PrintOptions &PO,
+             NonRecursivePrintOptions OPO = std::nullopt) const;
 
   /// Return the name of the type as a string, for use in diagnostics only.
-  std::string getString(const PrintOptions &PO = PrintOptions()) const;
+  std::string getString(const PrintOptions &PO = PrintOptions(),
+                        NonRecursivePrintOptions OPO = std::nullopt) const;
 
   /// Return the name of the type, adding parens in cases where
   /// appending or prepending text to the result would cause that text
@@ -360,7 +354,8 @@ class Type {
   /// the type would make it appear that it's appended to "Float" as
   /// opposed to the entire type.
   std::string
-  getStringAsComponent(const PrintOptions &PO = PrintOptions()) const;
+  getStringAsComponent(const PrintOptions &PO = PrintOptions(),
+                       NonRecursivePrintOptions OPO = std::nullopt) const;
 
   /// Computes the join between two types.
   ///
diff --git a/include/swift/AST/TypeAlignments.h b/include/swift/AST/TypeAlignments.h
index 827e9ba1313d6..c9b5d49b8f78a 100644
--- a/include/swift/AST/TypeAlignments.h
+++ b/include/swift/AST/TypeAlignments.h
@@ -26,6 +26,7 @@
 
 namespace swift {
   class AbstractClosureExpr;
+  class AbstractSpecializeAttr;
   class AbstractStorageDecl;
   class ArchetypeType;
   class AssociatedTypeDecl;
@@ -33,6 +34,7 @@ namespace swift {
   class AttributeBase;
   class BraceStmt;
   class CaptureListExpr;
+  class CustomAvailabilityDomain;
   class Decl;
   class DeclContext;
   class DifferentiableAttr;
@@ -54,6 +56,7 @@ namespace swift {
   class SILFunction;
   class SILFunctionType;
   class SpecializeAttr;
+  class SpecializedAttr;
   class Stmt;
   class TrailingWhereClause;
   class TypeVariableType;
@@ -78,6 +81,7 @@ namespace swift {
   constexpr size_t ASTContextAlignInBits = 2;
   constexpr size_t TypeVariableAlignInBits = 4;
   constexpr size_t StoredDefaultArgumentAlignInBits = 3;
+  constexpr size_t CustomAvailabilityDomainAlignInBits = 3;
 
   // Well, this is the *minimum* pointer alignment; it's going to be 3 on
   // 64-bit targets, but that doesn't matter.
@@ -149,6 +153,8 @@ LLVM_DECLARE_TYPE_ALIGNMENT(swift::RequirementRepr,
 LLVM_DECLARE_TYPE_ALIGNMENT(swift::SILFunction,
                             swift::SILFunctionAlignInBits)
 LLVM_DECLARE_TYPE_ALIGNMENT(swift::SpecializeAttr, swift::PointerAlignInBits)
+LLVM_DECLARE_TYPE_ALIGNMENT(swift::SpecializedAttr, swift::PointerAlignInBits)
+LLVM_DECLARE_TYPE_ALIGNMENT(swift::AbstractSpecializeAttr, swift::PointerAlignInBits)
 LLVM_DECLARE_TYPE_ALIGNMENT(swift::TrailingWhereClause,
                             swift::PointerAlignInBits)
 
@@ -161,6 +167,9 @@ LLVM_DECLARE_TYPE_ALIGNMENT(swift::CaseLabelItem, swift::PatternAlignInBits)
 LLVM_DECLARE_TYPE_ALIGNMENT(swift::StmtConditionElement,
                             swift::PatternAlignInBits)
 
+LLVM_DECLARE_TYPE_ALIGNMENT(swift::CustomAvailabilityDomain,
+                            swift::CustomAvailabilityDomainAlignInBits)
+
 static_assert(alignof(void*) >= 2, "pointer alignment is too small");
 
 #endif
diff --git a/include/swift/AST/TypeAttr.def b/include/swift/AST/TypeAttr.def
index 811e85a08d865..d03ad6ce013cb 100644
--- a/include/swift/AST/TypeAttr.def
+++ b/include/swift/AST/TypeAttr.def
@@ -67,7 +67,7 @@ TYPE_ATTR(_opaqueReturnTypeOf, OpaqueReturnTypeOf)
 TYPE_ATTR(isolated, Isolated)
 SIMPLE_TYPE_ATTR(nonisolated, Nonisolated)
 SIMPLE_TYPE_ATTR(_addressable, Addressable)
-TYPE_ATTR(execution, Execution)
+SIMPLE_TYPE_ATTR(concurrent, Concurrent)
 
 // SIL-specific attributes
 SIMPLE_SIL_TYPE_ATTR(async, Async)
@@ -95,6 +95,7 @@ SIMPLE_SIL_TYPE_ATTR(pack_out, PackOut)
 SIMPLE_SIL_TYPE_ATTR(owned, Owned)
 SIMPLE_SIL_TYPE_ATTR(unowned_inner_pointer, UnownedInnerPointer)
 SIMPLE_SIL_TYPE_ATTR(guaranteed, Guaranteed)
+SIMPLE_SIL_TYPE_ATTR(guaranteed_addr, GuaranteedAddress)
 SIMPLE_SIL_TYPE_ATTR(autoreleased, Autoreleased)
 SIMPLE_SIL_TYPE_ATTR(callee_owned, CalleeOwned)
 SIMPLE_SIL_TYPE_ATTR(callee_guaranteed, CalleeGuaranteed)
diff --git a/include/swift/AST/TypeCheckRequests.h b/include/swift/AST/TypeCheckRequests.h
index 112790754f961..1d56c937eb950 100644
--- a/include/swift/AST/TypeCheckRequests.h
+++ b/include/swift/AST/TypeCheckRequests.h
@@ -64,7 +64,7 @@ struct PropertyWrapperLValueness;
 struct PropertyWrapperMutability;
 class RequirementRepr;
 class ReturnStmt;
-class SpecializeAttr;
+class AbstractSpecializeAttr;
 class TrailingWhereClause;
 class TypeAliasDecl;
 class TypeLoc;
@@ -475,9 +475,31 @@ class ConformanceHasEffectRequest :
   bool isCached() const { return true; }
 };
 
+class RawConformanceIsolationRequest :
+    public SimpleRequest<RawConformanceIsolationRequest,
+                         std::optional<ActorIsolation>(NormalProtocolConformance *),
+                         RequestFlags::SeparatelyCached |
+                         RequestFlags::SplitCached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  std::optional<ActorIsolation>
+  evaluate(Evaluator &evaluator, NormalProtocolConformance *conformance) const;
+
+public:
+  // Separate caching.
+  bool isCached() const { return true; }
+  std::optional<std::optional<ActorIsolation>> getCachedResult() const;
+  void cacheResult(std::optional<ActorIsolation> result) const;
+};
+
 class ConformanceIsolationRequest :
     public SimpleRequest<ConformanceIsolationRequest,
-                         ActorIsolation(ProtocolConformance *),
+                         ActorIsolation(NormalProtocolConformance *),
                          RequestFlags::SeparatelyCached |
                          RequestFlags::SplitCached> {
 public:
@@ -488,7 +510,7 @@ class ConformanceIsolationRequest :
 
   // Evaluation.
   ActorIsolation
-  evaluate(Evaluator &evaluator, ProtocolConformance *conformance) const;
+  evaluate(Evaluator &evaluator, NormalProtocolConformance *conformance) const;
 
 public:
   // Separate caching.
@@ -648,7 +670,7 @@ struct WhereClauseOwner {
   /// The source of the where clause, which can be a generic parameter list
   /// or a declaration that can have a where clause.
   llvm::PointerUnion<GenericParamList *, TrailingWhereClause *,
-                     SpecializeAttr *, DifferentiableAttr *>
+                     AbstractSpecializeAttr *, DifferentiableAttr *>
       source;
 
   WhereClauseOwner() : dc(nullptr) {}
@@ -662,7 +684,7 @@ struct WhereClauseOwner {
   WhereClauseOwner(DeclContext *dc, TrailingWhereClause *where)
       : dc(dc), source(where) {}
 
-  WhereClauseOwner(DeclContext *dc, SpecializeAttr *attr)
+  WhereClauseOwner(DeclContext *dc, AbstractSpecializeAttr *attr)
       : dc(dc), source(attr) {}
 
   WhereClauseOwner(DeclContext *dc, DifferentiableAttr *attr)
@@ -735,6 +757,48 @@ class RequirementRequest :
   bool isCached() const;
 };
 
+/// Generate the Clang USR for the given declaration.
+class ClangUSRGenerationRequest
+    : public SimpleRequest<ClangUSRGenerationRequest,
+                           std::optional<std::string>(const ValueDecl *),
+                           RequestFlags::SeparatelyCached |
+                               RequestFlags::SplitCached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  std::optional<std::string> evaluate(Evaluator &eval,
+                                      const ValueDecl *d) const;
+
+public:
+  // Split caching.
+  bool isCached() const { return true; }
+  std::optional<std::optional<std::string>> getCachedResult() const;
+  void cacheResult(std::optional<std::string> result) const;
+};
+
+/// Generate the Swift USR for the given declaration.
+class SwiftUSRGenerationRequest
+    : public SimpleRequest<SwiftUSRGenerationRequest,
+                           std::string(const ValueDecl *),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  std::string evaluate(Evaluator &eval, const ValueDecl *d) const;
+
+public:
+  // Caching
+  bool isCached() const { return true; }
+};
+
 struct USRGenerationOptions {
   /// @brief Whether to emit USRs using the Swift declaration when it is
   /// synthesized from a Clang based declaration. Useful in cases where Swift
@@ -742,13 +806,21 @@ struct USRGenerationOptions {
   /// wants the USR of the Swift declaration.
   bool distinguishSynthesizedDecls;
 
+  /// @brief Whether to emit USRs using the Swift declaration for all
+  /// declarations specifically, emits a Swift USR for all Clang-based
+  /// declarations.
+  bool useSwiftUSR;
+
   friend llvm::hash_code hash_value(const USRGenerationOptions &options) {
-    return llvm::hash_value(options.distinguishSynthesizedDecls);
+    return llvm::hash_combine(
+        llvm::hash_value(options.distinguishSynthesizedDecls),
+        llvm::hash_value(options.useSwiftUSR));
   }
 
   friend bool operator==(const USRGenerationOptions &lhs,
                          const USRGenerationOptions &rhs) {
-    return lhs.distinguishSynthesizedDecls == rhs.distinguishSynthesizedDecls;
+    return lhs.distinguishSynthesizedDecls == rhs.distinguishSynthesizedDecls &&
+           lhs.useSwiftUSR == rhs.useSwiftUSR;
   }
 
   friend bool operator!=(const USRGenerationOptions &lhs,
@@ -761,10 +833,12 @@ void simple_display(llvm::raw_ostream &out,
                     const USRGenerationOptions &options);
 
 /// Generate the USR for the given declaration.
+/// This is an umbrella request that forwards to ClangUSRGenerationRequest or
+/// SwiftUSRGenerationRequest.
 class USRGenerationRequest
     : public SimpleRequest<USRGenerationRequest,
                            std::string(const ValueDecl *, USRGenerationOptions),
-                           RequestFlags::Cached> {
+                           RequestFlags::Uncached> {
 public:
   using SimpleRequest::SimpleRequest;
 
@@ -774,10 +848,6 @@ class USRGenerationRequest
   // Evaluation.
   std::string evaluate(Evaluator &eval, const ValueDecl *d,
                        USRGenerationOptions options) const;
-
-public:
-  // Caching
-  bool isCached() const { return true; }
 };
 
 /// Generate the mangling for the given local type declaration.
@@ -2861,7 +2931,7 @@ class SynthesizeDefaultInitRequest
 class CompareDeclSpecializationRequest
     : public SimpleRequest<CompareDeclSpecializationRequest,
                            bool(DeclContext *, ValueDecl *, ValueDecl *, bool,
-                                bool),
+                                bool, bool),
                            RequestFlags::Cached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -2871,8 +2941,8 @@ class CompareDeclSpecializationRequest
 
   // Evaluation.
   bool evaluate(Evaluator &evaluator, DeclContext *DC, ValueDecl *VD1,
-                ValueDecl *VD2, bool dynamic,
-                bool allowMissingConformances) const;
+                ValueDecl *VD2, bool dynamic, bool allowMissingConformances,
+                bool debugMode) const;
 
 public:
   // Caching.
@@ -3311,7 +3381,7 @@ class DynamicallyReplacedDeclRequest
 
 class SpecializeAttrTargetDeclRequest
     : public SimpleRequest<SpecializeAttrTargetDeclRequest,
-                           ValueDecl *(const ValueDecl *, SpecializeAttr *),
+                           ValueDecl *(const ValueDecl *, AbstractSpecializeAttr *),
                            RequestFlags::Cached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -3321,7 +3391,7 @@ class SpecializeAttrTargetDeclRequest
 
   // Evaluation.
   ValueDecl *evaluate(Evaluator &evaluator, const ValueDecl *vd,
-                      SpecializeAttr *attr) const;
+                      AbstractSpecializeAttr *attr) const;
 
 public:
   // Caching.
@@ -4019,6 +4089,31 @@ class PrimarySourceFilesRequest
   bool isCached() const { return true; }
 };
 
+/// Load the access notes to apply for the main module.
+///
+/// Note this is keyed on the ASTContext instead of the ModuleDecl to avoid
+/// needing to re-load the access notes in cases where we have multiple main
+/// modules, e.g when doing cached top-level code completion.
+///
+/// FIXME: This isn't really a type-checking request, if we ever split off a
+/// zone for more general requests, this should be moved there.
+class LoadAccessNotesRequest
+    : public SimpleRequest<LoadAccessNotesRequest,
+                           const AccessNotesFile *(ASTContext *),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  const AccessNotesFile *evaluate(Evaluator &evaluator, ASTContext *ctx) const;
+
+public:
+  // Cached.
+  bool isCached() const { return true; }
+};
+
 /// Kinds of types for CustomAttr.
 enum class CustomAttrTypeKind {
   /// The type is required to not be expressed in terms of
@@ -4853,6 +4948,62 @@ class TypeCheckObjCImplementationRequest
   bool isCached() const { return true; }
 };
 
+/// Check @c functions for compatibility with the foreign language.
+class TypeCheckCDeclFunctionRequest
+    : public SimpleRequest<TypeCheckCDeclFunctionRequest,
+                           evaluator::SideEffect(FuncDecl *FD,
+                                                 CDeclAttr *attr),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  evaluator::SideEffect
+  evaluate(Evaluator &evaluator, FuncDecl *FD, CDeclAttr *attr) const;
+
+public:
+  bool isCached() const { return true; }
+};
+
+/// A request to emit performance hints
+class EmitPerformanceHints
+: public SimpleRequest<EmitPerformanceHints,
+                       evaluator::SideEffect(SourceFile *),
+                       RequestFlags::Cached> {
+public:
+using SimpleRequest::SimpleRequest;
+
+private:
+friend SimpleRequest;
+
+evaluator::SideEffect
+evaluate(Evaluator &evaluator, SourceFile *SF) const;
+
+public:
+bool isCached() const { return true; }
+};
+
+/// Check @c enums for compatibility with C.
+class TypeCheckCDeclEnumRequest
+    : public SimpleRequest<TypeCheckCDeclEnumRequest,
+                           evaluator::SideEffect(EnumDecl *ED,
+                                                 CDeclAttr *attr),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  evaluator::SideEffect
+  evaluate(Evaluator &evaluator, EnumDecl *ED, CDeclAttr *attr) const;
+
+public:
+  bool isCached() const { return true; }
+};
+
 void simple_display(llvm::raw_ostream &out, ASTNode node);
 void simple_display(llvm::raw_ostream &out, Type value);
 void simple_display(llvm::raw_ostream &out, const TypeRepr *TyR);
@@ -4937,7 +5088,7 @@ class ExpandChildAvailabilityScopesRequest
 class SerializeAttrGenericSignatureRequest
     : public SimpleRequest<SerializeAttrGenericSignatureRequest,
                            GenericSignature(const AbstractFunctionDecl *,
-                                            SpecializeAttr *),
+                                            AbstractSpecializeAttr *),
                            RequestFlags::SeparatelyCached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -4947,7 +5098,7 @@ class SerializeAttrGenericSignatureRequest
 
   GenericSignature evaluate(Evaluator &evaluator,
                             const AbstractFunctionDecl *decl,
-                            SpecializeAttr *attr) const;
+                            AbstractSpecializeAttr *attr) const;
 
 public:
   // Separate caching.
@@ -5073,8 +5224,7 @@ class ImportDeclRequest
 class LifetimeDependenceInfoRequest
     : public SimpleRequest<
           LifetimeDependenceInfoRequest,
-          std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>(
-              AbstractFunctionDecl *),
+          std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>(ValueDecl *),
           RequestFlags::SeparatelyCached | RequestFlags::SplitCached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -5083,7 +5233,7 @@ class LifetimeDependenceInfoRequest
   friend SimpleRequest;
 
   std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>
-  evaluate(Evaluator &evaluator, AbstractFunctionDecl *AFD) const;
+  evaluate(Evaluator &evaluator, ValueDecl *AFD) const;
 
 public:
   // Separate caching.
@@ -5134,6 +5284,26 @@ class ParamCaptureInfoRequest :
   void cacheResult(CaptureInfo value) const;
 };
 
+class PatternBindingCaptureInfoRequest
+    : public SimpleRequest<PatternBindingCaptureInfoRequest,
+                           CaptureInfo(PatternBindingDecl *, unsigned),
+                           RequestFlags::SeparatelyCached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  CaptureInfo evaluate(Evaluator &evaluator, PatternBindingDecl *PBD,
+                       unsigned idx) const;
+
+public:
+  // Separate caching.
+  bool isCached() const { return true; }
+  std::optional<CaptureInfo> getCachedResult() const;
+  void cacheResult(CaptureInfo info) const;
+};
+
 class SuppressesConformanceRequest
     : public SimpleRequest<SuppressesConformanceRequest,
                            bool(NominalTypeDecl *decl, KnownProtocolKind kp),
@@ -5220,7 +5390,7 @@ SourceLoc extractNearestSourceLoc(RegexLiteralPatternFeatureKind kind);
 
 class GenericTypeParamDeclGetValueTypeRequest
     : public SimpleRequest<GenericTypeParamDeclGetValueTypeRequest,
-                           Type(GenericTypeParamDecl *decl),
+                           Type(const GenericTypeParamDecl *decl),
                            RequestFlags::Cached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -5228,7 +5398,7 @@ class GenericTypeParamDeclGetValueTypeRequest
 private:
   friend SimpleRequest;
 
-  Type evaluate(Evaluator &evaluator, GenericTypeParamDecl *decl) const;
+  Type evaluate(Evaluator &evaluator, const GenericTypeParamDecl *decl) const;
 
 public:
   bool isCached() const { return true; }
@@ -5293,24 +5463,97 @@ class SemanticAvailabilitySpecRequest
   void cacheResult(std::optional<SemanticAvailabilitySpec> value) const;
 };
 
-class SourceFileLangOptionsRequest
-    : public SimpleRequest<SourceFileLangOptionsRequest,
-                           SourceFileLangOptions(SourceFile *),
+class DefaultIsolationInSourceFileRequest
+    : public SimpleRequest<DefaultIsolationInSourceFileRequest,
+                           std::optional<DefaultIsolation>(const SourceFile *),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  std::optional<DefaultIsolation> evaluate(Evaluator &evaluator,
+                                           const SourceFile *file) const;
+
+public:
+  bool isCached() const { return true; }
+};
+
+/// Performs extension binding for all of the extensions in a module.
+class BindExtensionsRequest
+    : public SimpleRequest<BindExtensionsRequest,
+                           evaluator::SideEffect(ModuleDecl *),
                            RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  evaluator::SideEffect evaluate(Evaluator &evaluator, ModuleDecl *M) const;
+
+public:
+  bool isCached() const { return true; }
+};
+
+class ModuleHasTypeCheckerPerformanceHacksEnabledRequest
+    : public SimpleRequest<ModuleHasTypeCheckerPerformanceHacksEnabledRequest,
+                           bool(const ModuleDecl *),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  bool evaluate(Evaluator &evaluator, const ModuleDecl *module) const;
+
+public:
+  bool isCached() const { return true; }
+};
 
+class AvailabilityDomainForDeclRequest
+    : public SimpleRequest<AvailabilityDomainForDeclRequest,
+                           std::optional<AvailabilityDomain>(ValueDecl *),
+                           RequestFlags::Cached | RequestFlags::SplitCached> {
 public:
   using SimpleRequest::SimpleRequest;
 
 private:
   friend SimpleRequest;
 
-  SourceFileLangOptions evaluate(Evaluator &evaluator,
-                                 SourceFile *sourceFile) const;
+  std::optional<AvailabilityDomain> evaluate(Evaluator &evaluator,
+                                             ValueDecl *decl) const;
 
 public:
   bool isCached() const { return true; }
-  std::optional<SourceFileLangOptions> getCachedResult() const;
-  void cacheResult(SourceFileLangOptions value) const;
+  std::optional<std::optional<AvailabilityDomain>> getCachedResult() const;
+  void cacheResult(std::optional<AvailabilityDomain> domain) const;
+};
+
+class IsCustomAvailabilityDomainPermanentlyEnabled
+    : public SimpleRequest<IsCustomAvailabilityDomainPermanentlyEnabled,
+                           bool(const CustomAvailabilityDomain *),
+                           RequestFlags::SeparatelyCached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  bool evaluate(Evaluator &evaluator,
+                const CustomAvailabilityDomain *customDomain) const;
+
+public:
+  bool isCached() const { return true; }
+  std::optional<bool> getCachedResult() const;
+  void cacheResult(bool isPermanentlyEnabled) const;
+
+  SourceLoc getNearestLoc() const {
+    auto *domain = std::get<0>(getStorage());
+    return extractNearestSourceLoc(domain->getDecl());
+  }
 };
 
 #define SWIFT_TYPEID_ZONE TypeChecker
diff --git a/include/swift/AST/TypeCheckerTypeIDZone.def b/include/swift/AST/TypeCheckerTypeIDZone.def
index 5173cc5d3a196..e4f9df0fa6840 100644
--- a/include/swift/AST/TypeCheckerTypeIDZone.def
+++ b/include/swift/AST/TypeCheckerTypeIDZone.def
@@ -52,7 +52,7 @@ SWIFT_REQUEST(TypeChecker, CheckRedeclarationRequest,
 SWIFT_REQUEST(TypeChecker, ClassAncestryFlagsRequest,
               AncestryFlags(ClassDecl *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, CompareDeclSpecializationRequest,
-              bool (DeclContext *, ValueDecl *, ValueDecl *, bool, bool),
+              bool (DeclContext *, ValueDecl *, ValueDecl *, bool, bool, bool),
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ConditionalRequirementsRequest,
               ArrayRef<Requirement> (NormalProtocolConformance *),
@@ -96,7 +96,7 @@ SWIFT_REQUEST(TypeChecker, ABIMembersRequest,
 SWIFT_REQUEST(TypeChecker, AllMembersRequest,
               ArrayRef<Decl *>(IterableDeclContext *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, SpecializeAttrTargetDeclRequest,
-              ValueDecl *(const ValueDecl *, SpecializeAttr *),
+              ValueDecl *(const ValueDecl *, AbstractSpecializeAttr *),
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, EnumRawValuesRequest,
               evaluator::SideEffect (EnumDecl *, TypeResolutionStage),
@@ -275,6 +275,8 @@ SWIFT_REQUEST(TypeChecker, PatternBindingCheckedAndContextualizedInitRequest,
               SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, PrimarySourceFilesRequest,
               ArrayRef<SourceFile *>(ModuleDecl *), Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, LoadAccessNotesRequest,
+              const AccessNotesFile *(ASTContext *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, PropertyWrapperAuxiliaryVariablesRequest,
               PropertyWrapperAuxiliaryVariables(VarDecl *),
               SeparatelyCached | SplitCached,
@@ -364,9 +366,15 @@ SWIFT_REQUEST(TypeChecker, TypeCheckASTNodeAtLocRequest,
               Uncached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, UnderlyingTypeRequest, Type(TypeAliasDecl *),
               SeparatelyCached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, ClangUSRGenerationRequest,
+              std::optional<std::string>(const ValueDecl *),
+              SeparatelyCached | SplitCached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, SwiftUSRGenerationRequest,
+              std::string(const ValueDecl *),
+              Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, USRGenerationRequest,
               std::string(const ValueDecl *, USRGenerationOptions),
-              Cached, NoLocationInfo)
+              Uncached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, IsABICompatibleOverrideRequest,
               bool(ValueDecl *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, IsStaticRequest,
@@ -406,8 +414,12 @@ SWIFT_REQUEST(TypeChecker, PolymorphicEffectRequirementsRequest,
 SWIFT_REQUEST(TypeChecker, ConformanceHasEffectRequest,
               bool(EffectKind, ProtocolConformanceRef),
               Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, RawConformanceIsolationRequest,
+              std::optional<ActorIsolation>(NormalProtocolConformance *),
+              SeparatelyCached | SplitCached,
+              NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ConformanceIsolationRequest,
-              ActorIsolation(ProtocolConformance *),
+              ActorIsolation(NormalProtocolConformance *),
               SeparatelyCached | SplitCached,
               NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ResolveTypeRequest,
@@ -550,6 +562,12 @@ SWIFT_REQUEST(TypeChecker, IsNonUserModuleRequest,
 SWIFT_REQUEST(TypeChecker, TypeCheckObjCImplementationRequest,
               unsigned(ExtensionDecl *),
               Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, TypeCheckCDeclFunctionRequest,
+              evaluator::SideEffect(FunctionDecl *, CDeclAttr *),
+              Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, TypeCheckCDeclEnumRequest,
+              evaluator::SideEffect(EnumDecl *, CDeclAttr *),
+              Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, HasInitAccessorRequest,
               bool(AbstractStorageDecl *), Cached,
               NoLocationInfo)
@@ -561,7 +579,7 @@ SWIFT_REQUEST(TypeChecker, ExpandChildAvailabilityScopesRequest,
               std::vector<AvailabilityScope *>(AvailabilityScope *),
               SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, SerializeAttrGenericSignatureRequest,
-              GenericSignature(Decl *, SpecializeAttr *),
+              GenericSignature(Decl *, AbstractSpecializeAttr *),
               SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, IsFunctionBodySkippedRequest,
               bool(const AbstractFunctionDecl *),
@@ -608,12 +626,15 @@ SWIFT_REQUEST(TypeChecker, CaptureInfoRequest,
 SWIFT_REQUEST(TypeChecker, ParamCaptureInfoRequest,
               CaptureInfo(ParamDecl *),
               SeparatelyCached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, PatternBindingCaptureInfoRequest,
+              CaptureInfo(PatternBindingDecl *, unsigned),
+              SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, CustomDerivativesRequest,
               CustomDerivativesResult(SourceFile *),
               Cached, NoLocationInfo)
 
 SWIFT_REQUEST(TypeChecker, GenericTypeParamDeclGetValueTypeRequest,
-              Type(GenericTypeParamDecl *), Cached, NoLocationInfo)
+              Type(const GenericTypeParamDecl *), Cached, NoLocationInfo)
 
 SWIFT_REQUEST(TypeChecker, SemanticAvailableAttrRequest,
               std::optional<SemanticAvailableAttr>
@@ -624,5 +645,26 @@ SWIFT_REQUEST(TypeChecker, SemanticAvailabilitySpecRequest,
               (const AvailabilitySpec *, const DeclContext *),
               SeparatelyCached, NoLocationInfo)
 
-SWIFT_REQUEST(TypeChecker, SourceFileLangOptionsRequest,
-              SourceFileLangOptions (SourceFile *), Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, DefaultIsolationInSourceFileRequest,
+              std::optional<DefaultIsolation>(const SourceFile *),
+              Cached, NoLocationInfo)
+
+SWIFT_REQUEST(TypeChecker, BindExtensionsRequest,
+              evaluator::SideEffect(ModuleDecl *),
+              Cached, NoLocationInfo)
+
+SWIFT_REQUEST(TypeChecker, ModuleHasTypeCheckerPerformanceHacksEnabledRequest,
+              bool(const ModuleDecl *),
+              Cached, NoLocationInfo)
+
+SWIFT_REQUEST(TypeChecker, AvailabilityDomainForDeclRequest,
+              std::optional<AvailabilityDomain>(ValueDecl *),
+              Cached | SplitCached, NoLocationInfo)
+
+SWIFT_REQUEST(TypeChecker, IsCustomAvailabilityDomainPermanentlyEnabled,
+              bool(const CustomAvailabilityDomain *),
+              SeparatelyCached, NoLocationInfo)
+
+SWIFT_REQUEST(TypeChecker, EmitPerformanceHints,
+              evaluator::SideEffect(SourceFile *),
+              Cached, NoLocationInfo)
diff --git a/include/swift/AST/TypeMatcher.h b/include/swift/AST/TypeMatcher.h
index ab6d90eb2190d..31ac8e6ab299d 100644
--- a/include/swift/AST/TypeMatcher.h
+++ b/include/swift/AST/TypeMatcher.h
@@ -117,12 +117,6 @@ class TypeMatcher {
 #define SINGLETON_TYPE(SHORT_ID, ID) TRIVIAL_CASE(ID##Type)
 #include "swift/AST/TypeNodes.def"
 
-    bool visitUnresolvedType(CanUnresolvedType firstType, Type secondType,
-                             Type sugaredFirstType) {
-      // Unresolved types never match.
-      return mismatch(firstType.getPointer(), secondType, sugaredFirstType);
-    }
-
     bool visitTupleType(CanTupleType firstTuple, Type secondType,
                         Type sugaredFirstType) {
       if (auto secondTuple = secondType->getAs<TupleType>()) {
diff --git a/include/swift/AST/TypeMemberVisitor.h b/include/swift/AST/TypeMemberVisitor.h
index 7ad863f980968..479a84510d49d 100644
--- a/include/swift/AST/TypeMemberVisitor.h
+++ b/include/swift/AST/TypeMemberVisitor.h
@@ -41,6 +41,7 @@ class TypeMemberVisitor : public DeclVisitor<ImplClass, RetTy> {
   BAD_MEMBER(Operator)
   BAD_MEMBER(PrecedenceGroup)
   BAD_MEMBER(Macro)
+  BAD_MEMBER(Using)
 
   RetTy visitMacroExpansionDecl(MacroExpansionDecl *D) {
     // Expansion already visited as auxiliary decls.
diff --git a/include/swift/AST/TypeNodes.def b/include/swift/AST/TypeNodes.def
index 5ae2e5c658401..869a7cc7e99d5 100644
--- a/include/swift/AST/TypeNodes.def
+++ b/include/swift/AST/TypeNodes.def
@@ -123,7 +123,6 @@
 #if !defined(SINGLETON_TYPE)
 
 TYPE(Error, Type)
-UNCHECKED_TYPE(Unresolved, Type)
 UNCHECKED_TYPE(Placeholder, Type)
 ABSTRACT_TYPE(Builtin, Type)
   ABSTRACT_TYPE(AnyBuiltinInteger, BuiltinType)
@@ -177,7 +176,7 @@ TYPE(DynamicSelf, Type)
 ABSTRACT_TYPE(Substitutable, Type)
   ABSTRACT_TYPE(Archetype, SubstitutableType)
     ALWAYS_CANONICAL_TYPE(PrimaryArchetype, ArchetypeType)
-    ALWAYS_CANONICAL_TYPE(OpaqueTypeArchetype, ArchetypeType)
+    TYPE(OpaqueTypeArchetype, ArchetypeType)
     ABSTRACT_TYPE(LocalArchetype, ArchetypeType)
       ALWAYS_CANONICAL_TYPE(ExistentialArchetype, LocalArchetypeType)
       ALWAYS_CANONICAL_TYPE(ElementArchetype, LocalArchetypeType)
@@ -207,7 +206,7 @@ TYPE(PackExpansion, Type)
 TYPE(PackElement, Type)
 UNCHECKED_TYPE(TypeVariable, Type)
 UNCHECKED_TYPE(ErrorUnion, Type)
-ALWAYS_CANONICAL_TYPE(Integer, Type)
+TYPE(Integer, Type)
 ABSTRACT_SUGARED_TYPE(Sugar, Type)
   SUGARED_TYPE(TypeAlias, SugarType)
   SUGARED_TYPE(Locatable, SugarType)
diff --git a/include/swift/AST/TypeRepr.h b/include/swift/AST/TypeRepr.h
index 749cf72190223..13c37817aec13 100644
--- a/include/swift/AST/TypeRepr.h
+++ b/include/swift/AST/TypeRepr.h
@@ -205,8 +205,10 @@ class alignas(1 << TypeReprAlignInBits) TypeRepr
 
   //*** Allocation Routines ************************************************/
 
-  void print(raw_ostream &OS, const PrintOptions &Opts = PrintOptions()) const;
-  void print(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void print(raw_ostream &OS, const PrintOptions &opts = PrintOptions(),
+             NonRecursivePrintOptions nrOpts = std::nullopt) const;
+  void print(ASTPrinter &Printer, const PrintOptions &opts,
+             NonRecursivePrintOptions nrOpts = std::nullopt) const;
   SWIFT_DEBUG_DUMP;
   void dump(raw_ostream &OS, unsigned indent = 0) const;
 };
@@ -214,35 +216,29 @@ class alignas(1 << TypeReprAlignInBits) TypeRepr
 /// A TypeRepr for a type with a syntax error.  Can be used both as a
 /// top-level TypeRepr and as a part of other TypeRepr.
 ///
-/// The client can either emit a detailed diagnostic at the construction time
-/// (in the parser) or store a zero-arg diagnostic in this TypeRepr to be
-/// emitted after parsing, during type resolution.
-///
 /// All uses of this type should be ignored and not re-diagnosed.
 class ErrorTypeRepr : public TypeRepr {
   SourceRange Range;
-  std::optional<ZeroArgDiagnostic> DelayedDiag;
 
-  ErrorTypeRepr(SourceRange Range, std::optional<ZeroArgDiagnostic> Diag)
-      : TypeRepr(TypeReprKind::Error), Range(Range), DelayedDiag(Diag) {}
+  /// The original expression that failed to be resolved as a TypeRepr. Like
+  /// ErrorExpr's original expr, this exists to ensure that semantic
+  /// functionality can still work correctly, and is used to ensure we don't
+  /// drop nodes from the AST.
+  Expr *OriginalExpr;
 
-public:
-  static ErrorTypeRepr *
-  create(ASTContext &Context, SourceRange Range,
-         std::optional<ZeroArgDiagnostic> DelayedDiag = std::nullopt) {
-    assert((!DelayedDiag || Range) && "diagnostic needs a location");
-    return new (Context) ErrorTypeRepr(Range, DelayedDiag);
-  }
+  ErrorTypeRepr(SourceRange Range, Expr *OriginalExpr)
+      : TypeRepr(TypeReprKind::Error), Range(Range),
+        OriginalExpr(OriginalExpr) {}
 
-  static ErrorTypeRepr *
-  create(ASTContext &Context, SourceLoc Loc = SourceLoc(),
-         std::optional<ZeroArgDiagnostic> DelayedDiag = std::nullopt) {
-    return create(Context, SourceRange(Loc), DelayedDiag);
+public:
+  static ErrorTypeRepr *create(ASTContext &Context, SourceRange Range,
+                               Expr *OriginalExpr = nullptr) {
+    return new (Context) ErrorTypeRepr(Range, OriginalExpr);
   }
 
-  /// If there is a delayed diagnostic stored in this TypeRepr, consumes and
-  /// emits that diagnostic.
-  void dischargeDiagnostic(ASTContext &Context);
+  /// Retrieve the original expression that failed to be resolved as a TypeRepr.
+  Expr *getOriginalExpr() const { return OriginalExpr; }
+  void setOriginalExpr(Expr *newExpr) { OriginalExpr = newExpr; }
 
   static bool classof(const TypeRepr *T) {
     return T->getKind() == TypeReprKind::Error;
@@ -252,7 +248,8 @@ class ErrorTypeRepr : public TypeRepr {
 private:
   SourceLoc getStartLocImpl() const { return Range.Start; }
   SourceLoc getEndLocImpl() const { return Range.End; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -269,9 +266,7 @@ class AttributedTypeRepr final
       : TypeRepr(TypeReprKind::Attributed), Ty(Ty) {
     assert(!attrs.empty());
     Bits.AttributedTypeRepr.NumAttributes = attrs.size();
-    std::uninitialized_copy(attrs.begin(), attrs.end(),
-                            getTrailingObjects<TypeOrCustomAttr>());
-
+    std::uninitialized_copy(attrs.begin(), attrs.end(), getTrailingObjects());
   }
 
   friend TrailingObjects;
@@ -282,8 +277,7 @@ class AttributedTypeRepr final
                                     TypeRepr *ty);
 
   ArrayRef<TypeOrCustomAttr> getAttrs() const {
-    return llvm::ArrayRef(getTrailingObjects<TypeOrCustomAttr>(),
-                          Bits.AttributedTypeRepr.NumAttributes);
+    return getTrailingObjects(Bits.AttributedTypeRepr.NumAttributes);
   }
 
   TypeAttribute *get(TypeAttrKind kind) const;
@@ -303,7 +297,7 @@ class AttributedTypeRepr final
   ReferenceOwnership getSILOwnership() const;
 
   void printAttrs(llvm::raw_ostream &OS) const;
-  void printAttrs(ASTPrinter &Printer, const PrintOptions &Options) const;
+  void printAttrs(ASTPrinter &Printer, const PrintOptions &options) const;
 
   static bool classof(const TypeRepr *T) {
     return T->getKind() == TypeReprKind::Attributed;
@@ -316,12 +310,13 @@ class AttributedTypeRepr final
     if (auto customAttr = attr.dyn_cast<CustomAttr*>()) {
       return customAttr->getStartLoc();
     } else {
-      return attr.get<TypeAttribute*>()->getStartLoc();
+      return cast<TypeAttribute *>(attr)->getStartLoc();
     }
   }
   SourceLoc getEndLocImpl() const { return Ty->getEndLoc(); }
   SourceLoc getLocImpl() const { return Ty->getLoc(); }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -417,7 +412,8 @@ class DeclRefTypeRepr : public TypeRepr {
   SourceLoc getLocImpl() const;
   SourceLoc getEndLocImpl() const;
 
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts,
+                 NonRecursivePrintOptions nrOpts) const;
 
   friend class TypeRepr;
 };
@@ -610,7 +606,8 @@ class FunctionTypeRepr : public TypeRepr {
   SourceLoc getEndLocImpl() const { return RetTy->getEndLoc(); }
   SourceLoc getLocImpl() const { return ArrowLoc; }
 
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -637,11 +634,12 @@ class ArrayTypeRepr : public TypeRepr {
 private:
   SourceLoc getStartLocImpl() const { return Brackets.Start; }
   SourceLoc getEndLocImpl() const { return Brackets.End; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
-/// An InlineArray type e.g `[2 x Foo]`, sugar for `InlineArray<2, Foo>`.
+/// An InlineArray type e.g `[2 of Foo]`, sugar for `InlineArray<2, Foo>`.
 class InlineArrayTypeRepr : public TypeRepr {
   TypeRepr *Count;
   TypeRepr *Element;
@@ -666,7 +664,8 @@ class InlineArrayTypeRepr : public TypeRepr {
 private:
   SourceLoc getStartLocImpl() const { return Brackets.Start; }
   SourceLoc getEndLocImpl() const { return Brackets.End; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -699,7 +698,8 @@ class DictionaryTypeRepr : public TypeRepr {
 private:
   SourceLoc getStartLocImpl() const { return Brackets.Start; }
   SourceLoc getEndLocImpl() const { return Brackets.End; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -731,7 +731,8 @@ class OptionalTypeRepr : public TypeRepr {
   SourceLoc getLocImpl() const {
     return QuestionLoc.isValid() ? QuestionLoc : Base->getLoc();
   }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -760,7 +761,8 @@ class ImplicitlyUnwrappedOptionalTypeRepr : public TypeRepr {
   SourceLoc getStartLocImpl() const { return Base->getStartLoc(); }
   SourceLoc getEndLocImpl() const { return ExclamationLoc; }
   SourceLoc getLocImpl() const { return ExclamationLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -801,7 +803,8 @@ class VarargTypeRepr final : public TypeRepr {
   SourceLoc getStartLocImpl() const { return Element->getEndLoc(); }
   SourceLoc getEndLocImpl() const { return EllipsisLoc; }
   SourceLoc getLocImpl() const { return EllipsisLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -832,7 +835,8 @@ class PackExpansionTypeRepr final : public TypeRepr {
   SourceLoc getStartLocImpl() const { return RepeatLoc; }
   SourceLoc getEndLocImpl() const { return Pattern->getEndLoc(); }
   SourceLoc getLocImpl() const { return RepeatLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -863,12 +867,10 @@ class PackTypeRepr final
   SourceRange getBracesRange() const { return BraceLocs; }
 
   MutableArrayRef<TypeRepr*> getMutableElements() {
-    return llvm::MutableArrayRef(getTrailingObjects<TypeRepr *>(),
-                                 Bits.PackTypeRepr.NumElements);
+    return getTrailingObjects(Bits.PackTypeRepr.NumElements);
   }
   ArrayRef<TypeRepr*> getElements() const {
-    return llvm::ArrayRef(getTrailingObjects<TypeRepr *>(),
-                          Bits.PackTypeRepr.NumElements);
+    return getTrailingObjects(Bits.PackTypeRepr.NumElements);
   }
 
   static bool classof(const TypeRepr *T) {
@@ -880,7 +882,8 @@ class PackTypeRepr final
   SourceLoc getStartLocImpl() const { return KeywordLoc; }
   SourceLoc getEndLocImpl() const { return BraceLocs.End; }
   SourceLoc getLocImpl() const { return KeywordLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -915,7 +918,8 @@ class PackElementTypeRepr: public TypeRepr {
   SourceLoc getStartLocImpl() const { return EachLoc; }
   SourceLoc getEndLocImpl() const { return PackType->getEndLoc(); }
   SourceLoc getLocImpl() const { return EachLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -949,8 +953,8 @@ class TupleTypeRepr final : public TypeRepr,
   }
 
   ArrayRef<TupleTypeReprElement> getElements() const {
-    return { getTrailingObjects<TupleTypeReprElement>(),
-             static_cast<size_t>(Bits.TupleTypeRepr.NumElements) };
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.TupleTypeRepr.NumElements));
   }
 
   void getElementTypes(SmallVectorImpl<TypeRepr *> &Types) const {
@@ -1010,7 +1014,8 @@ class TupleTypeRepr final : public TypeRepr,
 private:
   SourceLoc getStartLocImpl() const { return Parens.Start; }
   SourceLoc getEndLocImpl() const { return Parens.End; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1030,13 +1035,13 @@ class CompositionTypeRepr final : public TypeRepr,
       : TypeRepr(TypeReprKind::Composition), FirstTypeLoc(FirstTypeLoc),
         CompositionRange(CompositionRange) {
     Bits.CompositionTypeRepr.NumTypes = Types.size();
-    std::uninitialized_copy(Types.begin(), Types.end(),
-                            getTrailingObjects<TypeRepr*>());
+    std::uninitialized_copy(Types.begin(), Types.end(), getTrailingObjects());
   }
 
 public:
   ArrayRef<TypeRepr *> getTypes() const {
-    return {getTrailingObjects<TypeRepr*>(), static_cast<size_t>(Bits.CompositionTypeRepr.NumTypes)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.CompositionTypeRepr.NumTypes));
   }
   SourceLoc getSourceLoc() const { return FirstTypeLoc; }
   SourceRange getCompositionRange() const { return CompositionRange; }
@@ -1066,7 +1071,8 @@ class CompositionTypeRepr final : public TypeRepr,
   SourceLoc getStartLocImpl() const { return FirstTypeLoc; }
   SourceLoc getLocImpl() const { return CompositionRange.Start; }
   SourceLoc getEndLocImpl() const { return CompositionRange.End; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1095,7 +1101,8 @@ class MetatypeTypeRepr : public TypeRepr {
   SourceLoc getStartLocImpl() const { return Base->getStartLoc(); }
   SourceLoc getEndLocImpl() const { return MetaLoc; }
   SourceLoc getLocImpl() const { return MetaLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1124,7 +1131,8 @@ class ProtocolTypeRepr : public TypeRepr {
   SourceLoc getStartLocImpl() const { return Base->getStartLoc(); }
   SourceLoc getEndLocImpl() const { return ProtocolLoc; }
   SourceLoc getLocImpl() const { return ProtocolLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1155,7 +1163,8 @@ class SpecifierTypeRepr : public TypeRepr {
 private:
   SourceLoc getStartLocImpl() const { return SpecifierLoc; }
   SourceLoc getEndLocImpl() const { return Base->getEndLoc(); }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1249,6 +1258,36 @@ class SendingTypeRepr : public SpecifierTypeRepr {
   static bool classof(const SendingTypeRepr *T) { return true; }
 };
 
+/// A 'nonisolated(nonsending)' function type.
+/// \code
+///   x : nonisolated(nonsending) () async -> Int
+/// \endcode
+class CallerIsolatedTypeRepr : public TypeRepr {
+  TypeRepr *Base;
+  SourceLoc Loc;
+
+public:
+  CallerIsolatedTypeRepr(TypeRepr *Base, SourceLoc Loc)
+      : TypeRepr(TypeReprKind::CallerIsolated), Base(Base), Loc(Loc) {
+    assert(Base);
+  }
+
+  TypeRepr *getBase() const { return Base; }
+
+  static bool classof(const TypeRepr *T) {
+    return T->getKind() == TypeReprKind::CallerIsolated;
+  }
+  static bool classof(const CallerIsolatedTypeRepr *T) { return true; }
+
+private:
+  SourceLoc getStartLocImpl() const { return Loc; }
+  SourceLoc getEndLocImpl() const { return Base->getEndLoc(); }
+  SourceLoc getLocImpl() const { return Base->getLoc(); }
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
+  friend class TypeRepr;
+};
+
 /// A TypeRepr for a known, fixed type.
 ///
 /// Fixed type representations should be used sparingly, in places
@@ -1282,7 +1321,8 @@ class FixedTypeRepr : public TypeRepr {
 private:
   SourceLoc getStartLocImpl() const { return Loc; }
   SourceLoc getEndLocImpl() const { return Loc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1309,7 +1349,8 @@ class SelfTypeRepr : public TypeRepr {
 private:
   SourceLoc getStartLocImpl() const { return Loc; }
   SourceLoc getEndLocImpl() const { return Loc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1362,7 +1403,8 @@ class OpaqueReturnTypeRepr : public TypeRepr {
   SourceLoc getStartLocImpl() const { return OpaqueLoc; }
   SourceLoc getEndLocImpl() const { return Constraint->getEndLoc(); }
   SourceLoc getLocImpl() const { return OpaqueLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1397,7 +1439,8 @@ class NamedOpaqueReturnTypeRepr : public TypeRepr {
   SourceLoc getStartLocImpl() const;
   SourceLoc getEndLocImpl() const;
   SourceLoc getLocImpl() const;
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1426,7 +1469,8 @@ class ExistentialTypeRepr: public TypeRepr {
   SourceLoc getStartLocImpl() const { return AnyLoc; }
   SourceLoc getEndLocImpl() const { return Constraint->getEndLoc(); }
   SourceLoc getLocImpl() const { return AnyLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1454,7 +1498,8 @@ class InverseTypeRepr : public TypeRepr {
   SourceLoc getStartLocImpl() const { return TildeLoc; }
   SourceLoc getEndLocImpl() const { return Constraint->getEndLoc(); }
   SourceLoc getLocImpl() const { return TildeLoc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1482,7 +1527,8 @@ class PlaceholderTypeRepr: public TypeRepr {
     SourceLoc getStartLocImpl() const { return UnderscoreLoc; }
     SourceLoc getEndLocImpl() const { return UnderscoreLoc; }
     SourceLoc getLocImpl() const { return UnderscoreLoc; }
-    void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+    void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
     friend class TypeRepr;
 };
 
@@ -1571,7 +1617,8 @@ class SILBoxTypeRepr final : public TypeRepr,
   SourceLoc getStartLocImpl() const;
   SourceLoc getEndLocImpl() const;
   SourceLoc getLocImpl() const;
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend TypeRepr;
 };
 
@@ -1598,7 +1645,8 @@ class LifetimeDependentTypeRepr final : public SpecifierTypeRepr {
   SourceLoc getStartLocImpl() const;
   SourceLoc getEndLocImpl() const;
   SourceLoc getLocImpl() const;
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1639,7 +1687,8 @@ class IntegerTypeRepr final : public TypeRepr {
 
   SourceLoc getEndLocImpl() const { return Loc; }
   SourceLoc getLocImpl() const { return Loc; }
-  void printImpl(ASTPrinter &Printer, const PrintOptions &Opts) const;
+  void printImpl(ASTPrinter &Printer, const PrintOptions &opts,
+                 NonRecursivePrintOptions nrOpts) const;
   friend class TypeRepr;
 };
 
@@ -1680,6 +1729,7 @@ inline bool TypeRepr::isSimple() const {
   case TypeReprKind::ConstValue:
   case TypeReprKind::LifetimeDependent:
   case TypeReprKind::Integer:
+  case TypeReprKind::CallerIsolated:
     return true;
   }
   llvm_unreachable("bad TypeRepr kind");
diff --git a/include/swift/AST/TypeReprNodes.def b/include/swift/AST/TypeReprNodes.def
index a1f7e51ded313..6a98b8f4dd3e6 100644
--- a/include/swift/AST/TypeReprNodes.def
+++ b/include/swift/AST/TypeReprNodes.def
@@ -77,6 +77,7 @@ TYPEREPR(Fixed, TypeRepr)
 TYPEREPR(SILBox, TypeRepr)
 TYPEREPR(Self, TypeRepr)
 TYPEREPR(LifetimeDependent, TypeRepr)
+TYPEREPR(CallerIsolated, TypeRepr)
 TYPEREPR(Integer, TypeRepr)
 LAST_TYPEREPR(Integer)
 
diff --git a/include/swift/AST/TypeTransform.h b/include/swift/AST/TypeTransform.h
index 8348506c836a8..1305c2695901e 100644
--- a/include/swift/AST/TypeTransform.h
+++ b/include/swift/AST/TypeTransform.h
@@ -109,7 +109,6 @@ case TypeKind::Id:
 #define TYPE(Id, Parent)
 #include "swift/AST/TypeNodes.def"
     case TypeKind::Error:
-    case TypeKind::Unresolved:
     case TypeKind::TypeVariable:
     case TypeKind::Placeholder:
     case TypeKind::SILToken:
@@ -358,7 +357,8 @@ case TypeKind::Id:
             }
           });
         if (didRemoveLifetimeDependencies) {
-          extInfo = extInfo.withLifetimeDependencies(substDependenceInfos);
+          extInfo = extInfo.withLifetimeDependencies(
+              ctx.AllocateCopy(substDependenceInfos));
         }
       }
 
@@ -939,7 +939,8 @@ case TypeKind::Id:
           });
 
         if (didRemoveLifetimeDependencies) {
-          extInfo = extInfo->withLifetimeDependencies(substDependenceInfos);
+          extInfo = extInfo->withLifetimeDependencies(
+              ctx.AllocateCopy(substDependenceInfos));
         }
       }
 
@@ -1176,6 +1177,12 @@ case TypeKind::Id:
     if (transformedPack.getPointer() == element->getPackType().getPointer())
       return element;
 
+    if (!transformedPack->isParameterPack() &&
+        !transformedPack->is<PackArchetypeType>() &&
+        !transformedPack->isTypeVariableOrMember()) {
+      return transformedPack;
+    }
+
     return PackElementType::get(transformedPack, element->getLevel());
   }
 
diff --git a/include/swift/AST/Types.h b/include/swift/AST/Types.h
index bc53a44510809..bf44de8fd514b 100644
--- a/include/swift/AST/Types.h
+++ b/include/swift/AST/Types.h
@@ -141,24 +141,24 @@ class RecursiveTypeProperties {
     /// This type expression contains a GenericTypeParamType.
     HasTypeParameter     = 0x04,
 
-    /// This type expression contains an UnresolvedType.
-    HasUnresolvedType    = 0x08,
-
     /// Whether this type expression contains an unbound generic type.
-    HasUnboundGeneric    = 0x10,
+    HasUnboundGeneric    = 0x08,
 
     /// This type expression contains an LValueType other than as a
     /// function input, and can be loaded to convert to an rvalue.
-    IsLValue             = 0x20,
+    IsLValue             = 0x10,
 
     /// This type expression contains an opened existential ArchetypeType.
-    HasOpenedExistential = 0x40,
+    HasOpenedExistential = 0x20,
 
     /// This type expression contains a DynamicSelf type.
-    HasDynamicSelf       = 0x80,
+    HasDynamicSelf       = 0x40,
 
     /// This type contains an Error type.
-    HasError             = 0x100,
+    HasError             = 0x80,
+
+    /// This type contains an Error type without an underlying original type.
+    HasBareError         = 0x100,
 
     /// This type contains a DependentMemberType.
     HasDependentMember   = 0x200,
@@ -225,15 +225,15 @@ class RecursiveTypeProperties {
   /// Does a type with these properties have a type parameter somewhere in it?
   bool hasTypeParameter() const { return Bits & HasTypeParameter; }
 
-  /// Does a type with these properties have an unresolved type somewhere in it?
-  bool hasUnresolvedType() const { return Bits & HasUnresolvedType; }
-
   /// Is a type with these properties an lvalue?
   bool isLValue() const { return Bits & IsLValue; }
 
   /// Does this type contain an error?
   bool hasError() const { return Bits & HasError; }
 
+  /// Does this type contain an error without an original type?
+  bool hasBareError() const { return Bits & HasBareError; }
+
   /// Does this type contain a dependent member type, possibly with a
   /// non-type parameter base, such as a type variable or concrete type?
   bool hasDependentMember() const { return Bits & HasDependentMember; }
@@ -318,6 +318,11 @@ class RecursiveTypeProperties {
     Bits &= ~HasDependentMember;
   }
 
+  /// Remove the IsUnsafe property from this set.
+  void removeIsUnsafe() {
+    Bits &= ~IsUnsafe;
+  }
+  
   /// Test for a particular property in this set.
   bool operator&(Property prop) const {
     return Bits & prop;
@@ -402,21 +407,25 @@ class alignas(1 << TypeAlignInBits) TypeBase
   }
 
 protected:
-  enum { NumAFTExtInfoBits = 15 };
+  enum { NumAFTExtInfoBits = 16 };
   enum { NumSILExtInfoBits = 14 };
 
   // clang-format off
   union { uint64_t OpaqueBits;
 
-  SWIFT_INLINE_BITFIELD_BASE(TypeBase, bitmax(NumTypeKindBits,8) +
-                             RecursiveTypeProperties::BitWidth + 1,
+  SWIFT_INLINE_BITFIELD_BASE(TypeBase, NumTypeKindBits +
+                             RecursiveTypeProperties::BitWidth + 1 + 3,
     /// Kind - The discriminator that indicates what subclass of type this is.
-    Kind : bitmax(NumTypeKindBits,8),
+    Kind : NumTypeKindBits,
 
     Properties : RecursiveTypeProperties::BitWidth,
 
     /// Whether this type is canonical or not.
-    IsCanonical : 1
+    IsCanonical : 1,
+
+    ComputedInvertibleConformances : 1,
+    IsCopyable : 1,
+    IsEscapable : 1
   );
 
   SWIFT_INLINE_BITFIELD(ErrorType, TypeBase, 1,
@@ -435,9 +444,7 @@ class alignas(1 << TypeAlignInBits) TypeBase
     HasExtInfo : 1,
     HasClangTypeInfo : 1,
     HasThrownError : 1,
-    HasLifetimeDependencies : 1,
-    : NumPadBits,
-    NumParams : 16
+    HasLifetimeDependencies : 1
   );
 
   SWIFT_INLINE_BITFIELD_FULL(ArchetypeType, TypeBase, 1+1+16,
@@ -450,9 +457,8 @@ class alignas(1 << TypeAlignInBits) TypeBase
   SWIFT_INLINE_BITFIELD_FULL(TypeVariableType, TypeBase, 7+28,
     /// Type variable options.
     Options : 7,
-    : NumPadBits,
     /// The unique number assigned to this type variable.
-    ID : 28
+    ID : 27
   );
 
   SWIFT_INLINE_BITFIELD_FULL(ErrorUnionType, TypeBase, 32,
@@ -555,6 +561,11 @@ class alignas(1 << TypeAlignInBits) TypeBase
       Bits.TypeBase.IsCanonical = true;
       Context = CanTypeCtx;
     }
+
+    Bits.TypeBase.ComputedInvertibleConformances = false;
+    Bits.TypeBase.IsCopyable = false;
+    Bits.TypeBase.IsEscapable = false;
+
     setRecursiveProperties(properties);
   }
 
@@ -586,6 +597,8 @@ class alignas(1 << TypeAlignInBits) TypeBase
 private:
   CanType computeCanonicalType();
 
+  void computeInvertibleConformances();
+
 public:
   /// getCanonicalType - Return the canonical version of this type, which has
   /// sugar from all levels stripped off.
@@ -685,6 +698,9 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// Copyable.
   bool isNoncopyable();
 
+  /// Returns true if this contextual type satisfies a conformance to Copyable.
+  bool isCopyable();
+
   /// Returns true if this contextual type satisfies a conformance to Escapable.
   bool isEscapable();
 
@@ -695,6 +711,14 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// Returns true if this contextual type is (Escapable && !isNoEscape).
   bool mayEscape() { return !isNoEscape() && isEscapable(); }
 
+  /// Returns true if this contextual type satisfies a conformance to
+  /// BitwiseCopyable.
+  bool isBitwiseCopyable();
+
+  /// Returns true if this type satisfies a conformance to BitwiseCopyable in
+  /// the given generic signature.
+  bool isBitwiseCopyable(GenericSignature sig);
+
   /// Are values of this type essentially just class references,
   /// possibly with some sort of additional information?
   ///
@@ -715,15 +739,16 @@ class alignas(1 << TypeAlignInBits) TypeBase
     return getRecursiveProperties().hasTypeVariable();
   }
 
+  // Convenience for checking whether the given type either has a type
+  // variable or placeholder.
+  bool hasTypeVariableOrPlaceholder() const {
+    return hasTypeVariable() || hasPlaceholder();
+  }
+
   /// Determine where this type is a type variable or a dependent
   /// member root in a type variable.
   bool isTypeVariableOrMember();
 
-  /// Determine whether this type involves a UnresolvedType.
-  bool hasUnresolvedType() const {
-    return getRecursiveProperties().hasUnresolvedType();
-  }
-
   /// Determine whether this type involves a \c PlaceholderType.
   bool hasPlaceholder() const {
     return getRecursiveProperties().hasPlaceholder();
@@ -824,12 +849,11 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// type variables referenced by this type.
   void getTypeVariables(SmallPtrSetImpl<TypeVariableType *> &typeVariables);
 
-private:
+public:
   /// If the receiver is a `DependentMemberType`, returns its root. Otherwise,
   /// returns the receiver.
   Type getDependentMemberRoot();
 
-public:
   /// Determine whether this type is a type parameter, which is either a
   /// GenericTypeParamType or a DependentMemberType.
   ///
@@ -918,6 +942,16 @@ class alignas(1 << TypeAlignInBits) TypeBase
     return getRecursiveProperties().hasError();
   }
 
+  /// Determine whether this type contains an error type without an
+  /// underlying original type, i.e prints as `_`.
+  bool hasBareError() const {
+    return getRecursiveProperties().hasBareError();
+  }
+
+  /// Whether this is a top-level ErrorType without an underlying original
+  /// type, i.e prints as `_`.
+  bool isBareErrorType() const;
+
   /// Does this type contain a dependent member type, possibly with a
   /// non-type parameter base, such as a type variable or concrete type?
   bool hasDependentMember() const {
@@ -982,9 +1016,13 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// type) from `DistributedActor`.
   bool isDistributedActor();
 
-  /// Determine if the type in question is an Array<T> and, if so, provide the
+  /// Determine if this type is an Array<T> and, if so, provide the element type
+  /// of the array.
+  Type getArrayElementType();
+
+  /// Determine if this type is an InlineArray<n, T> and, if so, provide the
   /// element type of the array.
-  Type isArrayType();
+  Type getInlineArrayElementType();
 
   /// Determines the element type of a known
   /// [Autoreleasing]Unsafe[Mutable][Raw]Pointer variant, or returns null if the
@@ -1049,6 +1087,9 @@ class alignas(1 << TypeAlignInBits) TypeBase
   bool is##NAME();
   #include "swift/AST/KnownStdlibTypes.def"
 
+  /// Check if this type is from the Builtin module.
+  bool isBuiltinType();
+
   /// Check if this type is equal to Builtin.IntN.
   bool isBuiltinIntegerType(unsigned bitWidth);
   
@@ -1059,6 +1100,21 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// on macOS or Foundation on Linux.
   bool isCGFloat();
 
+  /// Check if this is a ObjCBool type from the Objective-C module.
+  bool isObjCBool();
+
+  /// Check if this is a std.string type from C++.
+  bool isCxxString();
+
+  /// Check if this is the type Unicode.Scalar from the Swift standard library.
+  bool isUnicodeScalar();
+
+  /// Check if this type is known to represent key paths.
+  bool isKnownKeyPathType();
+
+  /// Check if this type is known to represent immutable key paths.
+  bool isKnownImmutableKeyPathType();
+
   /// Check if this is either an Array, Set or Dictionary collection type defined
   /// at the top level of the Swift module
   bool isKnownStdlibCollectionType();
@@ -1229,6 +1285,9 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// representation, i.e. whether it is representable as a single,
   /// possibly nil pointer that can be unknown-retained and
   /// unknown-released.
+  /// This does not include C++ imported `SWIFT_SHARED_REFERENCE` classes.
+  /// They act as Swift classes but are not compatible with Swift's
+  /// retain/release runtime functions.
   bool hasRetainablePointerRepresentation();
 
   /// Given that this type is a reference type, which kind of reference
@@ -1296,18 +1355,16 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// argument labels removed.
   Type removeArgumentLabels(unsigned numArgumentLabels);
 
-  /// Replace the base type of the result type of the given function
-  /// type with a new result type, as per a DynamicSelf or other
-  /// covariant return transformation.  The optionality of the
-  /// existing result will be preserved.
-  ///
-  /// \param newResultType The new result type.
-  ///
-  /// \param uncurryLevel The number of uncurry levels to apply before
-  /// replacing the type. With uncurry level == 0, this simply
-  /// replaces the current type with the new result type.
-  Type replaceCovariantResultType(Type newResultType,
-                                  unsigned uncurryLevel);
+  /// Replace DynamicSelfType anywhere it appears in covariant position with
+  /// its underlying Self type.
+  Type eraseDynamicSelfType();
+
+  /// Replace DynamicSelfType anywhere it appears in covariant position with
+  /// the given type.
+  Type replaceDynamicSelfType(Type newSelfType);
+
+  /// Hack to deal with ConstructorDecl interface types.
+  Type withCovariantResultType();
 
   /// Returns a new function type exactly like this one but with the self
   /// parameter replaced. Only makes sense for function members of types.
@@ -1479,8 +1536,10 @@ class alignas(1 << TypeAlignInBits) TypeBase
 
   SWIFT_DEBUG_DUMPER(print());
   void print(raw_ostream &OS,
-             const PrintOptions &PO = PrintOptions()) const;
-  void print(ASTPrinter &Printer, const PrintOptions &PO) const;
+             const PrintOptions &PO = PrintOptions(),
+             NonRecursivePrintOptions nrOptions = std::nullopt) const;
+  void print(ASTPrinter &Printer, const PrintOptions &PO,
+             NonRecursivePrintOptions nrOptions = std::nullopt) const;
 
   /// Can this type be written in source at all?
   ///
@@ -1493,7 +1552,8 @@ class alignas(1 << TypeAlignInBits) TypeBase
   bool hasSimpleTypeRepr() const;
 
   /// Return the name of the type as a string, for use in diagnostics only.
-  std::string getString(const PrintOptions &PO = PrintOptions()) const;
+  std::string getString(const PrintOptions &PO = PrintOptions(),
+                        NonRecursivePrintOptions nrOptions = std::nullopt) const;
 
   /// Return the name of the type, adding parens in cases where
   /// appending or prepending text to the result would cause that text
@@ -1502,7 +1562,8 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// the type would make it appear that it's appended to "Float" as
   /// opposed to the entire type.
   std::string
-  getStringAsComponent(const PrintOptions &PO = PrintOptions()) const;
+  getStringAsComponent(const PrintOptions &PO = PrintOptions(),
+                       NonRecursivePrintOptions nrOptions = std::nullopt) const;
 
   /// Return whether this type is or can be substituted for a bridgeable
   /// object type.
@@ -1599,11 +1660,19 @@ DEFINE_EMPTY_CAN_TYPE_WRAPPER(NominalOrBoundGenericNominalType, AnyGenericType)
 /// have to emit further diagnostics to abort compilation.
 class ErrorType final : public TypeBase {
   friend class ASTContext;
-  // The Error type is always canonical.
-  ErrorType(ASTContext &C, Type originalType,
-            RecursiveTypeProperties properties)
-      : TypeBase(TypeKind::Error, &C, properties) {
-    assert(properties.hasError());
+
+  static RecursiveTypeProperties getProperties(Type originalType) {
+    RecursiveTypeProperties props = RecursiveTypeProperties::HasError;
+    if (!originalType || originalType->hasBareError())
+      props |= RecursiveTypeProperties::HasBareError;
+
+    return props;
+  }
+
+  ErrorType(ASTContext &C, Type originalType)
+      : TypeBase(TypeKind::Error,
+                 (!originalType || originalType->isCanonical()) ? &C : nullptr,
+                 getProperties(originalType)) {
     if (originalType) {
       Bits.ErrorType.HasOriginalType = true;
       *reinterpret_cast<Type *>(this + 1) = originalType;
@@ -1634,25 +1703,6 @@ class ErrorType final : public TypeBase {
   }
 };
 DEFINE_EMPTY_CAN_TYPE_WRAPPER(ErrorType, Type)
-
-/// UnresolvedType - This represents a type variable that cannot be resolved to
-/// a concrete type because the expression is ambiguous.  This is produced when
-/// parsing expressions and producing diagnostics.  Any instance of this should
-/// cause the entire expression to be ambiguously typed.
-class UnresolvedType : public TypeBase {
-  friend class ASTContext;
-  // The Unresolved type is always canonical.
-  UnresolvedType(ASTContext &C)
-    : TypeBase(TypeKind::Unresolved, &C,
-       RecursiveTypeProperties(RecursiveTypeProperties::HasUnresolvedType)) { }
-public:
-  // Implement isa/cast/dyncast/etc.
-  static bool classof(const TypeBase *T) {
-    return T->getKind() == TypeKind::Unresolved;
-  }
-};
-DEFINE_EMPTY_CAN_TYPE_WRAPPER(UnresolvedType, Type)
-
   
 /// BuiltinType - An abstract class for all the builtin types.
 class BuiltinType : public TypeBase {
@@ -1734,18 +1784,10 @@ class BuiltinFixedArrayType : public BuiltinType, public llvm::FoldingSetNode {
   CanType Size;
   CanType ElementType;
   
-  static RecursiveTypeProperties
-  getRecursiveTypeProperties(CanType Size, CanType Element) {
-    RecursiveTypeProperties properties;
-    properties |= Size->getRecursiveProperties();
-    properties |= Element->getRecursiveProperties();
-    return properties;
-  }
-  
-  BuiltinFixedArrayType(CanType Size,
-                        CanType ElementType)
+  BuiltinFixedArrayType(CanType Size, CanType ElementType,
+                        RecursiveTypeProperties properties)
     : BuiltinType(TypeKind::BuiltinFixedArray, ElementType->getASTContext(),
-                  getRecursiveTypeProperties(Size, ElementType)),
+                  properties),
         Size(Size),
         ElementType(ElementType)
   {}
@@ -2298,22 +2340,24 @@ class TypeAliasType final
   /// Retrieve the parent of this type as written, e.g., the part that was
   /// written before ".", if provided.
   Type getParent() const {
-    return Bits.TypeAliasType.HasParent ? *getTrailingObjects<Type>()
-                                        : Type();
+    return Bits.TypeAliasType.HasParent ? *getTrailingObjects() : Type();
   }
 
   /// Retrieve the substitution map applied to the declaration's underlying
   /// to produce the described type.
-  SubstitutionMap getSubstitutionMap() const;
+  ///
+  /// \param wantContextualType If \c true, the substitution map will bind
+  /// outer local generic parameters to archetypes. Otherwise they will be left
+  /// unchanged.
+  SubstitutionMap getSubstitutionMap(bool wantContextualType = false) const;
 
   /// Get the direct generic arguments, which correspond to the generic
   /// arguments that are directly applied to the typealias declaration
   /// this type references.
   ArrayRef<Type> getDirectGenericArgs() const {
-    return ArrayRef<Type>(
-        getTrailingObjects<Type>() +
-        (Bits.TypeAliasType.HasParent ? 1 : 0),
-        Bits.TypeAliasType.GenericArgCount);
+    return ArrayRef<Type>(getTrailingObjects() +
+                              (Bits.TypeAliasType.HasParent ? 1 : 0),
+                          Bits.TypeAliasType.GenericArgCount);
   }
 
   SmallVector<Type, 2> getExpandedGenericArgs();
@@ -2704,16 +2748,16 @@ class TupleType final : public TypeBase, public llvm::FoldingSetNode,
 
   /// getElements - Return the elements of this tuple.
   ArrayRef<TupleTypeElt> getElements() const {
-    return {getTrailingObjects<TupleTypeElt>(), getNumElements()};
+    return getTrailingObjects(getNumElements());
   }
 
   const TupleTypeElt &getElement(unsigned i) const {
-    return getTrailingObjects<TupleTypeElt>()[i];
+    return getTrailingObjects()[i];
   }
 
   /// getElementType - Return the type of the specified element.
   Type getElementType(unsigned ElementNo) const {
-    return getTrailingObjects<TupleTypeElt>()[ElementNo].getType();
+    return getTrailingObjects()[ElementNo].getType();
   }
 
   TupleEltTypeArrayRef getElementTypes() const {
@@ -2743,7 +2787,7 @@ class TupleType final : public TypeBase, public llvm::FoldingSetNode,
       : TypeBase(TypeKind::Tuple, CanCtx, properties) {
     Bits.TupleType.Count = elements.size();
     std::uninitialized_copy(elements.begin(), elements.end(),
-                            getTrailingObjects<TupleTypeElt>());
+                            getTrailingObjects());
   }
 };
 BEGIN_CAN_TYPE_WRAPPER(TupleType, Type)
@@ -3307,7 +3351,8 @@ END_CAN_TYPE_WRAPPER(DynamicSelfType, Type)
 /// represented at the binary level as a single function pointer.
 class AnyFunctionType : public TypeBase {
   const Type Output;
-  
+  uint16_t NumParams;
+
 public:
   using Representation = FunctionTypeRepresentation;
 
@@ -3568,16 +3613,16 @@ class AnyFunctionType : public TypeBase {
       Bits.AnyFunctionType.HasThrownError = false;
       Bits.AnyFunctionType.HasLifetimeDependencies = false;
     }
-    Bits.AnyFunctionType.NumParams = NumParams;
-    assert(Bits.AnyFunctionType.NumParams == NumParams && "Params dropped!");
+    this->NumParams = NumParams;
+    assert(this->NumParams == NumParams && "Params dropped!");
     
-    if (Info) {
+    if (Info && CONDITIONAL_ASSERT_enabled()) {
       unsigned maxLifetimeTarget = NumParams + 1;
       if (auto outputFn = Output->getAs<AnyFunctionType>()) {
         maxLifetimeTarget += outputFn->getNumParams();
       }
       for (auto &dep : Info->getLifetimeDependencies()) {
-        assert(dep.getTargetIndex() < maxLifetimeTarget);
+        ASSERT(dep.getTargetIndex() < maxLifetimeTarget);
       }
     }
   }
@@ -3607,7 +3652,7 @@ class AnyFunctionType : public TypeBase {
 
   Type getResult() const { return Output; }
   ArrayRef<Param> getParams() const;
-  unsigned getNumParams() const { return Bits.AnyFunctionType.NumParams; }
+  unsigned getNumParams() const { return NumParams; }
 
   GenericSignature getOptGenericSignature() const;
   
@@ -3984,7 +4029,7 @@ class FunctionType final
 
   ArrayRef<LifetimeDependenceInfo> getLifetimeDependencies() const {
     if (!hasLifetimeDependencies())
-      return std::nullopt;
+      return {};
     return {getTrailingObjects<LifetimeDependenceInfo>(),
             getNumLifetimeDependencies()};
   }
@@ -4037,6 +4082,7 @@ struct ParameterListInfo {
   SmallBitVector propertyWrappers;
   SmallBitVector implicitSelfCapture;
   SmallBitVector inheritActorContext;
+  SmallBitVector alwaysInheritActorContext;
   SmallBitVector variadicGenerics;
   SmallBitVector sendingParameters;
 
@@ -4063,7 +4109,8 @@ struct ParameterListInfo {
 
   /// Whether the given parameter is a closure that should inherit the
   /// actor context from the context in which it was created.
-  bool inheritsActorContext(unsigned paramIdx) const;
+  std::pair<bool, InheritActorContextModifier>
+  inheritsActorContext(unsigned paramIdx) const;
 
   bool isVariadicGenericParameter(unsigned paramIdx) const;
 
@@ -4152,7 +4199,7 @@ class GenericFunctionType final
 
   ArrayRef<LifetimeDependenceInfo> getLifetimeDependencies() const {
     if (!hasLifetimeDependencies())
-      return std::nullopt;
+      return {};
     return {getTrailingObjects<LifetimeDependenceInfo>(),
             getNumLifetimeDependencies()};
   }
@@ -4733,7 +4780,7 @@ enum class ResultConvention : uint8_t {
   /// The validity of the return value is dependent on the 'self' parameter,
   /// so it may be invalidated if that parameter is released.
   UnownedInnerPointer,
-  
+
   /// This value has been (or may have been) returned autoreleased.
   /// The caller should make an effort to reclaim the autorelease.
   /// The type must be a class or class existential type, and this
@@ -4745,6 +4792,14 @@ enum class ResultConvention : uint8_t {
   /// depending on the pact type).  The callee is responsible for
   /// leaving an initialized object in each element of the pack.
   Pack,
+
+  /// The caller is responsible for using the returned address within a valid
+  /// scope. This is valid only for borrow and mutate accessors.
+  GuaranteedAddress,
+
+  /// The caller is responsible for using the returned value within a valid
+  /// scope. This is valid only for borrow accessors.
+  Guaranteed,
 };
 
 // Does this result require indirect storage for the purpose of reabstraction?
@@ -4901,6 +4956,14 @@ class SILResultInfo {
     return getConvention() == ResultConvention::Pack;
   }
 
+  bool isGuaranteedAddressResult() const {
+    return getConvention() == ResultConvention::GuaranteedAddress;
+  }
+
+  bool isGuaranteedResult() const {
+    return getConvention() == ResultConvention::Guaranteed;
+  }
+
   /// Transform this SILResultInfo by applying the user-provided
   /// function to its type.
   ///
@@ -5022,12 +5085,20 @@ enum class SILCoroutineKind : uint8_t {
 
 class SILFunctionConventions;
 
+Type substOpaqueTypesWithUnderlyingTypes(Type type,
+                                         TypeExpansionContext context);
 
 CanType substOpaqueTypesWithUnderlyingTypes(CanType type,
                                             TypeExpansionContext context);
+
 ProtocolConformanceRef
-substOpaqueTypesWithUnderlyingTypes(ProtocolConformanceRef ref, Type origType,
+substOpaqueTypesWithUnderlyingTypes(ProtocolConformanceRef ref,
+                                    TypeExpansionContext context);
+
+SubstitutionMap
+substOpaqueTypesWithUnderlyingTypes(SubstitutionMap subs,
                                     TypeExpansionContext context);
+
 namespace Lowering {
   class TypeConverter;
 }
@@ -5188,12 +5259,12 @@ class SILFunctionType final
   /// Given an existing ExtInfo, and a set of interface parameters and results
   /// destined for a new SILFunctionType, return a new ExtInfo with only the
   /// lifetime dependencies relevant after substitution.
-  static ExtInfo
-  getSubstLifetimeDependencies(GenericSignature genericSig,
-                               ExtInfo origExtInfo,
-                               ArrayRef<SILParameterInfo> params,
-                               ArrayRef<SILYieldInfo> yields,
-                               ArrayRef<SILResultInfo> results);
+  static ExtInfo getSubstLifetimeDependencies(GenericSignature genericSig,
+                                              ExtInfo origExtInfo,
+                                              ASTContext &context,
+                                              ArrayRef<SILParameterInfo> params,
+                                              ArrayRef<SILYieldInfo> yields,
+                                              ArrayRef<SILResultInfo> results);
 
   /// Return a structurally-identical function type with a slightly tweaked
   /// ExtInfo.
@@ -5333,6 +5404,20 @@ class SILFunctionType final
     return hasErrorResult() && getErrorResult().isFormalIndirect();
   }
 
+  bool hasGuaranteedResult() const {
+    if (getNumResults() != 1) {
+      return false;
+    }
+    return getResults()[0].isGuaranteedResult();
+  }
+
+  bool hasGuaranteedAddressResult() const {
+    if (getNumResults() != 1) {
+      return false;
+    }
+    return getResults()[0].isGuaranteedAddressResult();
+  }
+
   struct IndirectFormalResultFilter {
     bool operator()(SILResultInfo result) const {
       return result.isFormalIndirect();
@@ -5450,6 +5535,10 @@ class SILFunctionType final
     return getParameters().back();
   }
 
+  unsigned getSelfParameterIndex() const {
+    return NumParameters - 1;
+  }
+
   /// Return SILParameterInfo for the isolated parameter in this SILFunctionType
   /// if one exists. Returns None otherwise.
   std::optional<SILParameterInfo> maybeGetIsolatedParameter() const {
@@ -5632,7 +5721,7 @@ class SILFunctionType final
   // relative to the original FunctionType.
   ArrayRef<LifetimeDependenceInfo> getLifetimeDependencies() const {
     if (!hasLifetimeDependencies())
-      return std::nullopt;
+      return {};
     return {getTrailingObjects<LifetimeDependenceInfo>(),
             NumLifetimeDependencies};
   }
@@ -5647,6 +5736,24 @@ class SILFunctionType final
     return getLifetimeDependenceFor(getNumParameters());
   }
 
+  /// Return true of the specified parameter is addressable based on its type
+  /// lowering in 'caller's context. This includes @_addressableForDependencies
+  /// parameter types.
+  ///
+  /// Defined in SILType.cpp.
+  bool isAddressable(unsigned paramIdx, SILFunction *caller);
+
+  /// Return true of the specified parameter is addressable based on its type
+  /// lowering. This includes @_addressableForDependencies parameter types.
+  ///
+  /// 'genericEnv' may be null.
+  ///
+  /// Defined in SILType.cpp.
+  bool isAddressable(unsigned paramIdx, SILModule &module,
+                     GenericEnvironment *genericEnv,
+                     Lowering::TypeConverter &typeConverter,
+                     TypeExpansionContext expansion);
+
   /// Returns true if the function type stores a Clang type that cannot
   /// be derived from its Swift type. Returns false otherwise, including if
   /// the function type is not @convention(c) or @convention(block).
@@ -6035,7 +6142,7 @@ class SILMoveOnlyWrappedType final : public TypeBase,
         innerType(innerType) {
     // If it has a type parameter, we can't check whether it's copyable.
     assert(innerType->hasTypeParameter() ||
-           !innerType->isNoncopyable() && "Inner type must be copyable");
+           innerType->isCopyable() && "Inner type must be copyable");
   }
 
 public:
@@ -6125,7 +6232,7 @@ class SILPackType final : public TypeBase, public llvm::FoldingSetNode,
       : TypeBase(TypeKind::SILPack, &ctx, properties) {
     Bits.SILPackType.Count = elements.size();
     Bits.SILPackType.ElementIsAddress = info.ElementIsAddress;
-    memcpy(getTrailingObjects<CanType>(), elements.data(),
+    memcpy(getTrailingObjects(), elements.data(),
            elements.size() * sizeof(CanType));
   }
 
@@ -6147,13 +6254,13 @@ class SILPackType final : public TypeBase, public llvm::FoldingSetNode,
 
   /// Retrieves the type of the elements in the pack.
   ArrayRef<CanType> getElementTypes() const {
-    return {getTrailingObjects<CanType>(), getNumElements()};
+    return getTrailingObjects(getNumElements());
   }
 
   /// Returns the type of the element at the given \p index.
   /// This is a lowered SIL type.
   CanType getElementType(unsigned index) const {
-    return getTrailingObjects<CanType>()[index];
+    return getTrailingObjects()[index];
   }
 
   SILType getSILElementType(unsigned index) const; // in SILType.h
@@ -6255,7 +6362,7 @@ class ArraySliceType : public UnarySyntaxSugarType {
   }
 };
 
-/// An InlineArray type e.g `[2 x Foo]`, sugar for `InlineArray<2, Foo>`.
+/// An InlineArray type e.g `[2 of Foo]`, sugar for `InlineArray<2, Foo>`.
 class InlineArrayType : public SyntaxSugarType {
   Type Count;
   Type Elt;
@@ -6448,7 +6555,8 @@ class ProtocolCompositionType final : public TypeBase,
   /// a protocol composition type; you also have to look at
   /// hasExplicitAnyObject().
   ArrayRef<Type> getMembers() const {
-    return {getTrailingObjects<Type>(), static_cast<size_t>(Bits.ProtocolCompositionType.Count)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.ProtocolCompositionType.Count));
   }
 
   InvertibleProtocolSet getInverses() const { return Inverses; }
@@ -6496,7 +6604,7 @@ class ProtocolCompositionType final : public TypeBase,
     Bits.ProtocolCompositionType.HasExplicitAnyObject = hasExplicitAnyObject;
     Bits.ProtocolCompositionType.Count = members.size();
     std::uninitialized_copy(members.begin(), members.end(),
-                            getTrailingObjects<Type>());
+                            getTrailingObjects());
   }
 };
 BEGIN_CAN_TYPE_WRAPPER(ProtocolCompositionType, Type)
@@ -6545,8 +6653,8 @@ class ParameterizedProtocolType final : public TypeBase,
   }
 
   ArrayRef<Type> getArgs() const {
-    return {getTrailingObjects<Type>(),
-            static_cast<size_t>(Bits.ParameterizedProtocolType.ArgCount)};
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.ParameterizedProtocolType.ArgCount));
   }
 
   bool requiresClass() const {
@@ -6900,7 +7008,7 @@ class ArchetypeType : public SubstitutableType,
   }
 protected:
   ArchetypeType(TypeKind Kind,
-                const ASTContext &C,
+                const ASTContext *C,
                 RecursiveTypeProperties properties,
                 Type InterfaceType,
                 ArrayRef<ProtocolDecl *> ConformsTo,
@@ -6979,7 +7087,8 @@ class OpaqueTypeArchetypeType final : public ArchetypeType,
   }
 
 private:
-  OpaqueTypeArchetypeType(GenericEnvironment *environment,
+  OpaqueTypeArchetypeType(const ASTContext *ctx,
+                          GenericEnvironment *environment,
                           RecursiveTypeProperties properties,
                           Type interfaceType,
                           ArrayRef<ProtocolDecl*> conformsTo,
@@ -7011,31 +7120,28 @@ enum class OpaqueSubstitutionKind {
 /// archetypes with underlying types visible at a given resilience expansion
 /// to their underlying types.
 class ReplaceOpaqueTypesWithUnderlyingTypes {
-public:
-  using SeenDecl = std::pair<OpaqueTypeDecl *, SubstitutionMap>;
 private:
-  ResilienceExpansion contextExpansion;
-  llvm::PointerIntPair<const DeclContext *, 1, bool> inContextAndIsWholeModule;
-  llvm::DenseSet<SeenDecl> *seenDecls;
+  const DeclContext *inContext;
+  unsigned contextExpansion : 1;
+  bool isWholeModule : 1;
+  bool typeCheckFunctionBodies : 1;
 
 public:
   ReplaceOpaqueTypesWithUnderlyingTypes(const DeclContext *inContext,
                                         ResilienceExpansion contextExpansion,
-                                        bool isWholeModuleContext)
-      : contextExpansion(contextExpansion),
-        inContextAndIsWholeModule(inContext, isWholeModuleContext),
-        seenDecls(nullptr) {}
-
-  ReplaceOpaqueTypesWithUnderlyingTypes(
-      const DeclContext *inContext, ResilienceExpansion contextExpansion,
-      bool isWholeModuleContext, llvm::DenseSet<SeenDecl> &seen);
+                                        bool isWholeModule,
+                                        bool typeCheckFunctionBodies=true)
+      : inContext(inContext),
+        contextExpansion(unsigned(contextExpansion)),
+        isWholeModule(isWholeModule),
+        typeCheckFunctionBodies(typeCheckFunctionBodies) {}
 
   /// TypeSubstitutionFn
   Type operator()(SubstitutableType *maybeOpaqueType) const;
 
   /// LookupConformanceFn
-  ProtocolConformanceRef operator()(CanType maybeOpaqueType,
-                                    Type replacementType,
+  ProtocolConformanceRef operator()(InFlightSubstitution &IFS,
+                                    Type maybeOpaqueType,
                                     ProtocolDecl *protocol) const;
 
   OpaqueSubstitutionKind
@@ -7044,13 +7150,32 @@ class ReplaceOpaqueTypesWithUnderlyingTypes {
   static OpaqueSubstitutionKind
   shouldPerformSubstitution(OpaqueTypeDecl *opaque, ModuleDecl *contextModule,
                             ResilienceExpansion contextExpansion);
+};
 
+/// A function object that can be used as a \c TypeSubstitutionFn and
+/// \c LookupConformanceFn for \c Type::subst style APIs to map existential
+/// archetypes in the given generic environment to known concrete types from
+/// the given substitution map.
+class ReplaceExistentialArchetypesWithConcreteTypes {
 private:
-  const DeclContext *getContext() const {
-    return inContextAndIsWholeModule.getPointer();
-  }
+  GenericEnvironment *env;
+  SubstitutionMap subs;
+
+  Type getInterfaceType(ExistentialArchetypeType *type) const;
+
+public:
+  ReplaceExistentialArchetypesWithConcreteTypes(GenericEnvironment *env,
+                                                SubstitutionMap subs)
+      : env(env), subs(subs) {}
+
+  /// TypeSubstitutionFn
+  Type operator()(SubstitutableType *type) const;
+
+  /// LookupConformanceFn
+  ProtocolConformanceRef operator()(InFlightSubstitution &IFS,
+                                    Type origType,
+                                    ProtocolDecl *protocol) const;
 
-  bool isWholeModule() const { return inContextAndIsWholeModule.getInt(); }
 };
 
 /// An archetype that's only valid in a portion of a local context.
@@ -7107,11 +7232,13 @@ class ExistentialArchetypeType final : public LocalArchetypeType,
   }
   
 private:
-  ExistentialArchetypeType(GenericEnvironment *environment, Type interfaceType,
-                      ArrayRef<ProtocolDecl *> conformsTo,
-                      Type superclass,
-                      LayoutConstraint layout,
-                      RecursiveTypeProperties properties);
+  ExistentialArchetypeType(const ASTContext *ctx,
+                           GenericEnvironment *environment,
+                           Type interfaceType,
+                           ArrayRef<ProtocolDecl *> conformsTo,
+                           Type superclass,
+                           LayoutConstraint layout,
+                           RecursiveTypeProperties properties);
 };
 BEGIN_CAN_TYPE_WRAPPER(ExistentialArchetypeType, LocalArchetypeType)
 END_CAN_TYPE_WRAPPER(ExistentialArchetypeType, LocalArchetypeType)
@@ -7184,7 +7311,7 @@ class ElementArchetypeType final : public LocalArchetypeType,
   }
   
 private:
-  ElementArchetypeType(const ASTContext &ctx,
+  ElementArchetypeType(const ASTContext *ctx,
                        GenericEnvironment *environment, Type interfaceType,
                        ArrayRef<ProtocolDecl *> conformsTo, Type superclass,
                        LayoutConstraint layout);
@@ -7225,9 +7352,10 @@ class GenericTypeParamType : public SubstitutableType,
     Identifier Name;
   };
 
-  unsigned Depth : 15;
   unsigned IsDecl : 1;
-  unsigned Index : 16;
+  unsigned Depth : 15;
+  unsigned Weight : 1;
+  unsigned Index : 15;
 
   /// The kind of generic type parameter this is.
   GenericTypeParamKind ParamKind;
@@ -7252,15 +7380,21 @@ class GenericTypeParamType : public SubstitutableType,
                                    Type valueType, const ASTContext &ctx);
 
   /// Retrieve a canonical generic type parameter with the given kind, depth,
-  /// index, and optional value type.
+  /// index, weight, and optional value type.
   static GenericTypeParamType *get(GenericTypeParamKind paramKind,
-                                   unsigned depth, unsigned index,
+                                   unsigned depth, unsigned index, unsigned weight,
                                    Type valueType, const ASTContext &ctx);
 
-  /// Retrieve a canonical generic type parameter at the given depth and index.
+  /// Retrieve a canonical generic type parameter at the given depth and index,
+  /// with weight 0.
   static GenericTypeParamType *getType(unsigned depth, unsigned index,
                                        const ASTContext &ctx);
 
+  /// Retrieve a canonical generic type parameter at the given depth and index
+  /// for an opaque result type, so with weight 1.
+  static GenericTypeParamType *getOpaqueResultType(unsigned depth, unsigned index,
+                                                   const ASTContext &ctx);
+
   /// Retrieve a canonical generic parameter pack at the given depth and index.
   static GenericTypeParamType *getPack(unsigned depth, unsigned index,
                                        const ASTContext &ctx);
@@ -7316,6 +7450,14 @@ class GenericTypeParamType : public SubstitutableType,
     return Index;
   }
 
+  /// The weight of this generic parameter in the type parameter order.
+  ///
+  /// Opaque result types have weight 1, while all other generic parameters
+  /// have weight 0.
+  unsigned getWeight() const {
+    return Weight;
+  }
+
   /// Returns \c true if this type parameter is declared as a pack.
   ///
   /// \code
@@ -7337,20 +7479,24 @@ class GenericTypeParamType : public SubstitutableType,
 
   Type getValueType() const;
 
+  GenericTypeParamType *withDepth(unsigned depth) const;
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     // Note: We explicitly don't use 'getName()' because for canonical forms
     // which don't store an identifier we'll go create a tau based form. We
     // really want to just plumb down the null Identifier because that's what's
     // inside the cache.
-    Profile(ID, getParamKind(), getDepth(), getIndex(), getValueType(),
-            Name);
+    Profile(ID, getParamKind(), getDepth(), getIndex(), getWeight(),
+            getValueType(), Name);
   }
   static void Profile(llvm::FoldingSetNodeID &ID,
                       GenericTypeParamKind paramKind, unsigned depth,
-                      unsigned index, Type valueType, Identifier name) {
+                      unsigned index, unsigned weight, Type valueType,
+                      Identifier name) {
     ID.AddInteger((uint8_t)paramKind);
     ID.AddInteger(depth);
     ID.AddInteger(index);
+    ID.AddInteger(weight);
     ID.AddPointer(valueType.getPointer());
     ID.AddPointer(name.get());
   }
@@ -7373,7 +7519,7 @@ class GenericTypeParamType : public SubstitutableType,
                                 const ASTContext &ctx);
 
   explicit GenericTypeParamType(GenericTypeParamKind paramKind, unsigned depth,
-                                unsigned index, Type valueType,
+                                unsigned index, unsigned weight, Type valueType,
                                 RecursiveTypeProperties props,
                                 const ASTContext &ctx);
 };
@@ -7383,6 +7529,11 @@ static CanGenericTypeParamType getType(unsigned depth, unsigned index,
   return CanGenericTypeParamType(
       GenericTypeParamType::getType(depth, index, C));
 }
+static CanGenericTypeParamType getOpaqueResultType(unsigned depth, unsigned index,
+                                                   const ASTContext &C) {
+  return CanGenericTypeParamType(
+      GenericTypeParamType::getOpaqueResultType(depth, index, C));
+}
 END_CAN_TYPE_WRAPPER(GenericTypeParamType, SubstitutableType)
 
 /// A type that refers to a member type of some type that is dependent on a
@@ -7587,8 +7738,7 @@ class ErrorUnionType final
                  RecursiveTypeProperties properties) 
         : TypeBase(TypeKind::ErrorUnion, /*Context=*/ctx, properties) {
     Bits.ErrorUnionType.NumTerms = terms.size();
-    std::uninitialized_copy(terms.begin(), terms.end(),
-                            getTrailingObjects<Type>());
+    std::uninitialized_copy(terms.begin(), terms.end(), getTrailingObjects());
   }
 
 public:
@@ -7596,7 +7746,8 @@ class ErrorUnionType final
   static Type get(const ASTContext &ctx, ArrayRef<Type> terms);
 
   ArrayRef<Type> getTerms() const {
-    return { getTrailingObjects<Type>(), static_cast<size_t>(Bits.ErrorUnionType.NumTerms) };
+    return getTrailingObjects(
+        static_cast<size_t>(Bits.ErrorUnionType.NumTerms));
   };
 
   // Support for FoldingSet.
@@ -7613,16 +7764,16 @@ class ErrorUnionType final
 };
 DEFINE_EMPTY_CAN_TYPE_WRAPPER(ErrorUnionType, Type)
 
-/// PlaceholderType - This represents a placeholder type for a type variable
-/// or dependent member type that cannot be resolved to a concrete type
-/// because the expression is ambiguous. This type is only used by the
-/// constraint solver and transformed into UnresolvedType to be used in AST.
+/// PlaceholderType - In the AST, this represents the type of a placeholder `_`.
+/// In the constraint system, this is opened into a type variable, and uses of
+/// PlaceholderType are instead used to represent holes where types cannot be
+/// inferred.
 class PlaceholderType : public TypeBase {
   // NOTE: If you add a new Type-based originator, you'll need to update the
   // recursive property logic in PlaceholderType::get.
   using Originator =
-      llvm::PointerUnion<TypeVariableType *, DependentMemberType *, VarDecl *,
-                         ErrorExpr *, TypeRepr *>;
+      llvm::PointerUnion<TypeVariableType *, DependentMemberType *, ErrorType *,
+                         VarDecl *, ErrorExpr *, TypeRepr *, Pattern *>;
 
   Originator O;
 
@@ -7688,12 +7839,12 @@ class PackType final : public TypeBase, public llvm::FoldingSetNode,
 
   /// Retrieves the type of the elements in the pack.
   ArrayRef<Type> getElementTypes() const {
-    return {getTrailingObjects<Type>(), getNumElements()};
+    return getTrailingObjects(getNumElements());
   }
 
   /// Returns the type of the element at the given \p index.
   Type getElementType(unsigned index) const {
-    return getTrailingObjects<Type>()[index];
+    return getTrailingObjects()[index];
   }
 
   bool containsPackExpansionType() const;
@@ -7719,7 +7870,7 @@ class PackType final : public TypeBase, public llvm::FoldingSetNode,
      : TypeBase(TypeKind::Pack, CanCtx, properties) {
      Bits.PackType.Count = elements.size();
      std::uninitialized_copy(elements.begin(), elements.end(),
-                             getTrailingObjects<Type>());
+                             getTrailingObjects());
   }
 };
 BEGIN_CAN_TYPE_WRAPPER(PackType, Type)
@@ -7908,10 +8059,27 @@ class IntegerType final : public TypeBase, public llvm::FoldingSetNode {
   friend class ASTContext;
 
   StringRef Value;
+  // Integers may not be canonical, but don't have any structural type
+  // components from which to get the ASTContext, so we need to store a
+  // reference to it ourselves.
+  const ASTContext &Context;
+
+  static const ASTContext *
+  getCanonicalIntegerLiteralContext(StringRef value, const ASTContext &ctx) {
+    for (char c : value) {
+      // A canonical integer literal consists only of ASCII decimal digits.
+      if (c < '0' || c > '9') {
+        return nullptr;
+      }
+    }
+    return &ctx;
+  }
 
   IntegerType(StringRef value, bool isNegative, const ASTContext &ctx) :
-      TypeBase(TypeKind::Integer, &ctx, RecursiveTypeProperties()),
-      Value(value) {
+      TypeBase(TypeKind::Integer, getCanonicalIntegerLiteralContext(value, ctx),
+               RecursiveTypeProperties()),
+      Value(value),
+      Context(ctx) {
     Bits.IntegerType.IsNegative = isNegative;
   }
 
@@ -7941,6 +8109,8 @@ class IntegerType final : public TypeBase, public llvm::FoldingSetNode {
   static bool classof(const TypeBase *T) {
     return T->getKind() == TypeKind::Integer;
   }
+  
+  const ASTContext &getASTContext() { return Context; }
 };
 DEFINE_EMPTY_CAN_TYPE_WRAPPER(IntegerType, Type)
 
@@ -7960,6 +8130,17 @@ inline ASTContext &TypeBase::getASTContext() const {
   return *const_cast<ASTContext*>(getCanonicalType()->Context);
 }
 
+inline bool TypeBase::isBareErrorType() const {
+  auto *errTy = dyn_cast<ErrorType>(this);
+  if (!errTy)
+    return false;
+
+  // FIXME: We shouldn't need to check for a recursive bare error type, we can
+  // remove this once we flatten them.
+  auto originalTy = errTy->getOriginalType();
+  return !originalTy || originalTy->isBareErrorType();
+}
+
 // TODO: This will become redundant once InOutType is removed.
 inline bool TypeBase::isMaterializable() {
   return !(hasLValueType() || is<InOutType>());
@@ -8095,6 +8276,10 @@ inline GenericTypeDecl *TypeBase::getAnyGeneric() {
   return getCanonicalType().getAnyGeneric();
 }
 
+inline bool TypeBase::isBuiltinType() {
+  return isa<BuiltinType>(getCanonicalType());
+}
+
 inline bool TypeBase::isBuiltinIntegerType(unsigned n) {
   if (auto intTy = dyn_cast<BuiltinIntegerType>(getCanonicalType()))
     return intTy->getWidth().isFixedWidth()
@@ -8184,11 +8369,11 @@ inline ParameterTypeFlags ParameterTypeFlags::fromParameterType(
 
 inline const Type *BoundGenericType::getTrailingObjectsPointer() const {
   if (auto ty = dyn_cast<BoundGenericStructType>(this))
-    return ty->getTrailingObjects<Type>();
+    return ty->getTrailingObjects();
   if (auto ty = dyn_cast<BoundGenericEnumType>(this))
-    return ty->getTrailingObjects<Type>();
+    return ty->getTrailingObjects();
   if (auto ty = dyn_cast<BoundGenericClassType>(this))
-    return ty->getTrailingObjects<Type>();
+    return ty->getTrailingObjects();
   llvm_unreachable("Unhandled BoundGenericType!");
 }
 
diff --git a/include/swift/AST/USRGeneration.h b/include/swift/AST/USRGeneration.h
index 07e069b70aa38..61095c43e2a10 100644
--- a/include/swift/AST/USRGeneration.h
+++ b/include/swift/AST/USRGeneration.h
@@ -45,9 +45,20 @@ bool printDeclTypeUSR(const ValueDecl *D, raw_ostream &OS);
 /// Prints out the USR for the given ValueDecl.
 /// @param distinguishSynthesizedDecls Whether to use the USR of the
 /// synthesized declaration instead of the USR of the underlying Clang USR.
+/// @param useSwiftUSR Whether to generate a Swift USR for all Clang
+/// declarations as well.
 /// \returns true if it failed, false on success.
 bool printValueDeclUSR(const ValueDecl *D, raw_ostream &OS,
-                       bool distinguishSynthesizedDecls = false);
+                       bool distinguishSynthesizedDecls = false,
+                       bool useSwiftUSR = false);
+
+/// Prints out the Swift USR for the given ValueDecl regardless of its source
+/// (Swift or Clang). Equivalent to `printValueDeclUSR(D, OS, false,
+/// /*useSwiftUSR=*/true)`
+inline bool printValueDeclSwiftUSR(const ValueDecl *D, raw_ostream &OS) {
+  return printValueDeclUSR(D, OS, /*distinguishSynthesizedDecls=*/false,
+                           /*useSwiftUSR=*/true);
+}
 
 /// Prints out the USR for the given ModuleEntity.
 /// In case module aliasing is used, it prints the real module name. For example,
diff --git a/include/swift/AST/UnsafeUse.h b/include/swift/AST/UnsafeUse.h
index 70f8f2ecc2aec..bed9a9c0d328d 100644
--- a/include/swift/AST/UnsafeUse.h
+++ b/include/swift/AST/UnsafeUse.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -53,6 +53,8 @@ class UnsafeUse {
     ReferenceToUnsafeThroughTypealias,
     /// A call to an unsafe declaration.
     CallToUnsafe,
+    /// An unsafe argument in a call.
+    CallArgument,
     /// A @preconcurrency import.
     PreconcurrencyImport,
     /// A use of withoutActuallyEscaping that lacks enforcement that the
@@ -91,6 +93,15 @@ class UnsafeUse {
 
     MakeTemporarilyEscapableExpr *temporarilyEscaping;
 
+    struct {
+      Expr *call;
+      const Decl *calleeDecl;
+      TypeBase *paramType;
+      const void *argumentName;
+      unsigned argumentIndex;
+      Expr *argument;
+    } callArgument;
+
     const ImportDecl *importDecl;
   } storage;
 
@@ -201,6 +212,19 @@ class UnsafeUse {
                         decl, type, location);
   }
 
+  static UnsafeUse forCallArgument(
+      Expr *call, const Decl *calleeDecl, Type paramType,
+      Identifier argumentName, unsigned argumentIndex, Expr *argument) {
+    UnsafeUse result(CallArgument);
+    result.storage.callArgument.call = call;
+    result.storage.callArgument.calleeDecl = calleeDecl;
+    result.storage.callArgument.paramType = paramType.getPointer();
+    result.storage.callArgument.argumentName = argumentName.getAsOpaquePointer();
+    result.storage.callArgument.argumentIndex = argumentIndex;
+    result.storage.callArgument.argument = argument;
+    return result;
+  }
+
   static UnsafeUse forTemporarilyEscaping(MakeTemporarilyEscapableExpr *expr) {
     UnsafeUse result(TemporarilyEscaping);
     result.storage.temporarilyEscaping = expr;
@@ -223,14 +247,12 @@ class UnsafeUse {
       return getDecl()->getLoc();
 
     case UnsafeConformance:
-      return SourceLoc(
-          llvm::SMLoc::getFromPointer(
-            (const char *)storage.conformance.location));
+      return SourceLoc::getFromPointer(
+          (const char *)storage.conformance.location);
 
     case TypeWitness:
-      return SourceLoc(
-          llvm::SMLoc::getFromPointer(
-            (const char *)storage.typeWitness.location));
+      return SourceLoc::getFromPointer(
+          (const char *)storage.typeWitness.location);
 
     case UnownedUnsafe:
     case ExclusivityUnchecked:
@@ -239,8 +261,10 @@ class UnsafeUse {
     case ReferenceToUnsafeStorage:
     case ReferenceToUnsafeThroughTypealias:
     case CallToUnsafe:
-      return SourceLoc(
-          llvm::SMLoc::getFromPointer((const char *)storage.entity.location));
+      return SourceLoc::getFromPointer((const char *)storage.entity.location);
+
+    case CallArgument:
+      return storage.callArgument.call->getLoc();
 
     case TemporarilyEscaping:
       return storage.temporarilyEscaping->getLoc();
@@ -257,6 +281,7 @@ class UnsafeUse {
     case Witness:
     case TemporarilyEscaping:
     case PreconcurrencyImport:
+    case CallArgument:
       // Cannot replace location.
       return;
 
@@ -298,6 +323,9 @@ class UnsafeUse {
     case CallToUnsafe:
       return storage.entity.decl;
 
+    case CallArgument:
+      return storage.callArgument.calleeDecl;
+
     case UnsafeConformance:
     case TemporarilyEscaping:
       return nullptr;
@@ -330,6 +358,7 @@ class UnsafeUse {
     case ReferenceToUnsafeThroughTypealias:
     case ReferenceToUnsafeStorage:
     case CallToUnsafe:
+    case CallArgument:
     case UnsafeConformance:
     case PreconcurrencyImport:
     case TemporarilyEscaping:
@@ -360,6 +389,9 @@ class UnsafeUse {
     case CallToUnsafe:
       return storage.entity.type;
 
+    case CallArgument:
+      return storage.callArgument.paramType;
+
     case TemporarilyEscaping:
       return storage.temporarilyEscaping->getOpaqueValue()->getType();
     }
@@ -386,11 +418,24 @@ class UnsafeUse {
     case ReferenceToUnsafeStorage:
     case ReferenceToUnsafeThroughTypealias:
     case CallToUnsafe:
+    case CallArgument:
     case TemporarilyEscaping:
     case PreconcurrencyImport:
       return ProtocolConformanceRef::forInvalid();
     }
   }
+
+  /// Get information about the call argument.
+  ///
+  /// Produces the argument name, argument index, and argument expression for
+  /// a unsafe use describing a call argument.
+  std::tuple<Identifier, unsigned, Expr *> getCallArgument() const {
+    assert(getKind() == CallArgument);
+    return std::make_tuple(
+        Identifier::getFromOpaquePointer(storage.callArgument.argumentName),
+        storage.callArgument.argumentIndex,
+        storage.callArgument.argument);
+  }
 };
 
 } // end namespace swift
diff --git a/include/swift/Basic/Assertions.h b/include/swift/Basic/Assertions.h
index d8155add80baf..37b83d4fb8cd4 100644
--- a/include/swift/Basic/Assertions.h
+++ b/include/swift/Basic/Assertions.h
@@ -17,6 +17,8 @@
 #ifndef SWIFT_BASIC_ASSERTIONS_H
 #define SWIFT_BASIC_ASSERTIONS_H
 
+#include "swift/Basic/LLVM.h"
+
 // Only for use in this header
 #if __has_builtin(__builtin_expect)
 #define ASSERT_UNLIKELY(expression) (__builtin_expect(!!(expression), 0))
@@ -24,6 +26,13 @@
 #define ASSERT_UNLIKELY(expression) ((expression))
 #endif
 
+// Visual Studio doesn't have __FILE_NAME__
+#ifdef __FILE_NAME__
+#define _FILENAME_FOR_ASSERT __FILE_NAME__
+#else
+#define _FILENAME_FOR_ASSERT __FILE__
+#endif
+
 // ================================ Mandatory Asserts ================================
 
 // `ASSERT(expr)`:
@@ -41,27 +50,13 @@
 // that are more expensive than you think.  You can switch those to
 // `CONDITIONAL_ASSERT` or `DEBUG_ASSERT` as needed.
 
-// Visual Studio doesn't have __FILE_NAME__
-#ifdef __FILE_NAME__
-
-#define ASSERT(expr) \
-  do { \
-    if (ASSERT_UNLIKELY(!(expr))) {			   \
-      ASSERT_failure(#expr, __FILE_NAME__, __LINE__, __func__); \
-    } \
+#define ASSERT(expr)                                                           \
+  do {                                                                         \
+    if (ASSERT_UNLIKELY(!(expr))) {                                            \
+      ASSERT_failure(#expr, _FILENAME_FOR_ASSERT, __LINE__, __func__);         \
+    }                                                                          \
   } while (0)
 
-#else
-
-#define ASSERT(expr) \
-  do { \
-    if (ASSERT_UNLIKELY(!(expr))) {			   \
-      ASSERT_failure(#expr, __FILE__, __LINE__, __func__); \
-    } \
-  } while (0)
-
-#endif
-
 // Function that reports the actual failure when it occurs.
 void ASSERT_failure(const char *expr, const char *file, int line, const char *func);
 
@@ -190,11 +185,33 @@ extern int CONDITIONAL_ASSERT_Global_enable_flag;
 #define SWIFT_ASSERT_ONLY_DECL DEBUG_ASSERT_DECL
 #define SWIFT_ASSERT_ONLY DEBUG_ASSERT_EXPR
 
-// ================================ Utility and Helper Functions ================================
+// ================================ Abort ======================================
 
-// Utility function to print out help information for
-// various command-line options that affect the assertion
-// behavior.
-void ASSERT_help();
+/// Implementation for \c ABORT, not to be used directly.
+[[noreturn]]
+void _ABORT(const char *file, int line, const char *func,
+            llvm::function_ref<void(llvm::raw_ostream &)> message);
+
+/// Implementation for \c ABORT, not to be used directly.
+[[noreturn]]
+void _ABORT(const char *file, int line, const char *func,
+            llvm::StringRef message);
+
+// Aborts the program, printing a given message to a PrettyStackTrace frame
+// before exiting. This should be preferred over manually logging to stderr and
+// `abort()`'ing since that won't be picked up by the crash reporter.
+//
+// There are two different forms of ABORT:
+//
+// ```
+// ABORT("abort with string");
+//
+// ABORT([&](auto &out) {
+//   out << "abort with arbitrary stream";
+//   node.dump(out);
+// });
+// ```
+//
+#define ABORT(arg) _ABORT(_FILENAME_FOR_ASSERT, __LINE__, __func__, (arg))
 
 #endif // SWIFT_BASIC_ASSERTIONS_H
diff --git a/include/swift/Basic/BasicBridging.h b/include/swift/Basic/BasicBridging.h
index 36ea6df43908f..f0b1073e51b0b 100644
--- a/include/swift/Basic/BasicBridging.h
+++ b/include/swift/Basic/BasicBridging.h
@@ -13,61 +13,40 @@
 #ifndef SWIFT_BASIC_BASICBRIDGING_H
 #define SWIFT_BASIC_BASICBRIDGING_H
 
-#if !defined(COMPILED_WITH_SWIFT) || !defined(PURE_BRIDGING_MODE)
-#define USED_IN_CPP_SOURCE
-#endif
-
-// Do not add other C++/llvm/swift header files here!
-// Function implementations should be placed into BasicBridging.cpp and required header files should be added there.
-//
-// Pure bridging mode does not permit including any C++/llvm/swift headers.
-// See also the comments for `BRIDGING_MODE` in the top-level CMakeLists.txt file.
-//
+// Do not add other std/llvm header files here!
+// Function implementations should be placed into BasicBridging.cpp and
+// required header files should be added there.
 //
-// Note: On Windows ARM64, how a C++ struct/class value type is
-// returned is sensitive to conditions including whether a
-// user-defined constructor exists, etc. See
-// https://learn.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=msvc-170#return-values
-// So, if a C++ struct/class type is returned as a value between Swift
-// and C++, we need to be careful to match the return convention
-// matches between the non-USED_IN_CPP_SOURCE (Swift) side and the
-// USE_IN_CPP_SOURCE (C++) side.
+// Pure bridging mode does not permit including any std/llvm headers.
+// See also the comments for `BRIDGING_MODE` in the top-level CMakeLists.txt
+// file.
 //
 // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-// !! Do not put any constructors inside an `#ifdef USED_IN_CPP_SOURCE` block !!
+// !! Do not put any constructors inside an                                   !!
+// !! `#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE` block               !!
 // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
-#include "swift/Basic/BridgedSwiftObject.h"
-#include "swift/Basic/Compiler.h"
+/// This header defines `NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE`, so it
+/// needs to be imported before the first use of the macro.
+#include "swift/Basic/SwiftBridging.h"
 
+#include "swift/Basic/BridgedSwiftObject.h"
+#include "swift/Basic/SourceLoc.h"
 #include <stddef.h>
 #include <stdint.h>
-#ifdef USED_IN_CPP_SOURCE
+
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 // Workaround to avoid a compiler error because `cas::ObjectRef` is not defined
 // when including VirtualFileSystem.h
 #include <cassert>
 #include "llvm/CAS/CASReference.h"
 
-#include "swift/Basic/SourceLoc.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/APInt.h"
 #include <string>
 #include <vector>
 #endif
 
-// FIXME: We ought to be importing '<swift/bridging>' instead.
-#if __has_attribute(swift_name)
-#define SWIFT_NAME(NAME) __attribute__((swift_name(NAME)))
-#else
-#define SWIFT_NAME(NAME)
-#endif
-
-#if __has_attribute(availability)
-#define SWIFT_UNAVAILABLE(msg) \
-  __attribute__((availability(swift, unavailable, message=msg)))
-#else
-#define SWIFT_UNAVAILABLE(msg)
-#endif
-
 #ifdef PURE_BRIDGING_MODE
 // In PURE_BRIDGING_MODE, briding functions are not inlined
 #define BRIDGED_INLINE
@@ -82,6 +61,7 @@ class VersionTuple;
 } // end namespace llvm
 
 namespace swift {
+class LangOptions;
 class SourceLoc;
 class SourceRange;
 class CharSourceRange;
@@ -110,13 +90,10 @@ typedef uintptr_t SwiftUInt;
                                                                                \
     SWIFT_UNAVAILABLE("Use '.raw' instead")                                    \
     Qualifier Node *Nullability unbridged() const { return Ptr; }              \
-  };                                                                           \
                                                                                \
-  SWIFT_NAME("getter:Bridged" #Name ".raw(self:)")                             \
-  inline Qualifier void *Nullability Bridged##Name##_getRaw(                   \
-      Bridged##Name bridged) {                                                 \
-    return bridged.unbridged();                                                \
-  }                                                                            \
+    SWIFT_COMPUTED_PROPERTY                                                    \
+    Qualifier void *Nullability getRaw() const { return unbridged(); };        \
+  };                                                                           \
                                                                                \
   SWIFT_NAME("Bridged" #Name ".init(raw:)")                                    \
   inline Bridged##Name Bridged##Name##_fromRaw(                                \
@@ -140,6 +117,10 @@ typedef uintptr_t SwiftUInt;
 void assertFail(const char * _Nonnull msg, const char * _Nonnull file,
                 SwiftUInt line, const char * _Nonnull function);
 
+BRIDGED_INLINE
+SWIFT_UNAVAILABLE("Unavailable in Swift")
+void ASSERT_inBridgingHeader(bool condition);
+
 //===----------------------------------------------------------------------===//
 // MARK: ArrayRef
 //===----------------------------------------------------------------------===//
@@ -158,7 +139,7 @@ class BridgedArrayRef {
   BridgedArrayRef(const void *_Nullable data, size_t length)
       : Data(data), Length(length) {}
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
   template <typename T>
   BridgedArrayRef(llvm::ArrayRef<T> arr)
       : Data(arr.data()), Length(arr.size()) {}
@@ -168,20 +149,19 @@ class BridgedArrayRef {
     return {static_cast<const T *>(Data), Length};
   }
 #endif
-};
 
-SWIFT_NAME("getter:BridgedArrayRef.data(self:)")
-BRIDGED_INLINE
-const void *_Nullable BridgedArrayRef_data(BridgedArrayRef arr);
+  SWIFT_COMPUTED_PROPERTY
+  const void *_Nullable getData() const { return Data; }
 
-SWIFT_NAME("getter:BridgedArrayRef.count(self:)")
-BRIDGED_INLINE SwiftInt BridgedArrayRef_count(BridgedArrayRef arr);
+  SWIFT_COMPUTED_PROPERTY
+  SwiftInt getCount() const { return static_cast<SwiftInt>(Length); }
 
-SWIFT_NAME("getter:BridgedArrayRef.isEmpty(self:)")
-BRIDGED_INLINE bool BridgedArrayRef_isEmpty(BridgedArrayRef arr);
+  SWIFT_COMPUTED_PROPERTY
+  bool getIsEmpty() const { return Length == 0; }
+};
 
 //===----------------------------------------------------------------------===//
-// MARK: Data
+// MARK: BridgedData
 //===----------------------------------------------------------------------===//
 
 class BridgedData {
@@ -197,17 +177,15 @@ class BridgedData {
   SWIFT_NAME("init(baseAddress:count:)")
   BridgedData(const char *_Nullable baseAddress, size_t length)
       : BaseAddress(baseAddress), Length(length) {}
-};
 
-SWIFT_NAME("getter:BridgedData.baseAddress(self:)")
-BRIDGED_INLINE
-const char *_Nullable BridgedData_baseAddress(BridgedData data);
+  SWIFT_COMPUTED_PROPERTY
+  const char *_Nullable getBaseAddress() const { return BaseAddress; }
 
-SWIFT_NAME("getter:BridgedData.count(self:)")
-BRIDGED_INLINE SwiftInt BridgedData_count(BridgedData data);
+  SWIFT_COMPUTED_PROPERTY
+  SwiftInt getCount() const { return static_cast<SwiftInt>(Length); }
 
-SWIFT_NAME("BridgedData.free(self:)")
-void BridgedData_free(BridgedData data);
+  void free() const;
+};
 
 //===----------------------------------------------------------------------===//
 // MARK: Feature
@@ -238,18 +216,17 @@ class BridgedStringRef {
   BridgedStringRef(const char *_Nullable data, size_t length)
       : Data(data), Length(length) {}
 
-  void write(BridgedOStream os) const;
-};
+  SWIFT_COMPUTED_PROPERTY
+  const uint8_t *_Nullable getData() const { return (const uint8_t *)Data; }
 
-SWIFT_NAME("getter:BridgedStringRef.data(self:)")
-BRIDGED_INLINE 
-const uint8_t *_Nullable BridgedStringRef_data(BridgedStringRef str);
+  SWIFT_COMPUTED_PROPERTY
+  SwiftInt getCount() const { return Length; }
 
-SWIFT_NAME("getter:BridgedStringRef.count(self:)")
-BRIDGED_INLINE SwiftInt BridgedStringRef_count(BridgedStringRef str);
+  SWIFT_COMPUTED_PROPERTY
+  bool getIsEmpty() const { return Length == 0; }
 
-SWIFT_NAME("getter:BridgedStringRef.isEmpty(self:)")
-BRIDGED_INLINE bool BridgedStringRef_empty(BridgedStringRef str);
+  void write(BridgedOStream os) const;
+};
 
 class BridgedOwnedString {
   char *_Nonnull Data;
@@ -257,21 +234,59 @@ class BridgedOwnedString {
 
 public:
   BridgedOwnedString(llvm::StringRef stringToCopy);
-
   BRIDGED_INLINE llvm::StringRef unbridgedRef() const;
 
+  SWIFT_COMPUTED_PROPERTY
+  const uint8_t *_Nonnull getData() const {
+    return (const uint8_t *)(Data ? Data : "");
+  }
+
+  SWIFT_COMPUTED_PROPERTY
+  SwiftInt getCount() const { return Length; }
+
+  SWIFT_COMPUTED_PROPERTY
+  bool getIsEmpty() const { return Length == 0; }
+
   void destroy() const;
 } SWIFT_SELF_CONTAINED;
 
-SWIFT_NAME("getter:BridgedOwnedString.data(self:)")
-BRIDGED_INLINE 
-const uint8_t *_Nullable BridgedOwnedString_data(BridgedOwnedString str);
-
-SWIFT_NAME("getter:BridgedOwnedString.count(self:)")
-BRIDGED_INLINE SwiftInt BridgedOwnedString_count(BridgedOwnedString str);
+//===----------------------------------------------------------------------===//
+// MARK: BridgedOptional
+//===----------------------------------------------------------------------===//
 
-SWIFT_NAME("getter:BridgedOwnedString.isEmpty(self:)")
-BRIDGED_INLINE bool BridgedOwnedString_empty(BridgedOwnedString str);
+// FIXME: We should be able to make this a template once
+// https://github.com/swiftlang/swift/issues/82258 is fixed.
+#define BRIDGED_OPTIONAL(TYPE, SUFFIX)                                         \
+  class SWIFT_CONFORMS_TO_PROTOCOL(Swift.ExpressibleByNilLiteral)              \
+      BridgedOptional##SUFFIX {                                                \
+    TYPE _value;                                                               \
+    bool _hasValue;                                                            \
+                                                                               \
+  public:                                                                      \
+    SWIFT_NAME("init(nilLiteral:)")                                            \
+    BridgedOptional##SUFFIX(void) : _hasValue(false) {}                        \
+    BridgedOptional##SUFFIX(TYPE value) : _value(value), _hasValue(true) {}    \
+                                                                               \
+    SWIFT_COMPUTED_PROPERTY                                                    \
+    TYPE getValue() const {                                                    \
+      ASSERT_inBridgingHeader(_hasValue);                                      \
+      return _value;                                                           \
+    }                                                                          \
+                                                                               \
+    SWIFT_COMPUTED_PROPERTY                                                    \
+    bool getHasValue() const { return _hasValue; }                             \
+  };
+BRIDGED_OPTIONAL(SwiftInt, Int)
+
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+inline BridgedOptionalInt getFromAPInt(llvm::APInt i) {
+  if (i.getSignificantBits() <=
+      std::min(std::numeric_limits<SwiftInt>::digits, 64)) {
+    return {(SwiftInt)i.getSExtValue()};
+  }
+  return {};
+}
+#endif
 
 //===----------------------------------------------------------------------===//
 // MARK: OStream
@@ -284,9 +299,16 @@ class BridgedOStream {
   SWIFT_UNAVAILABLE("Use init(raw:) instead")
   BridgedOStream(llvm::raw_ostream * _Nonnull os) : os(os) {}
 
+  SWIFT_NAME("init(raw:)")
+  BridgedOStream(void *_Nonnull os)
+      : os(static_cast<llvm::raw_ostream *>(os)) {}
+
   SWIFT_UNAVAILABLE("Use '.raw' instead")
   llvm::raw_ostream * _Nonnull unbridged() const { return os; }
 
+  SWIFT_COMPUTED_PROPERTY
+  void *_Nonnull getRaw(BridgedOStream bridged) const { return unbridged(); }
+
   void write(BridgedStringRef string) const;
 
   void newLine() const;
@@ -294,102 +316,8 @@ class BridgedOStream {
   void flush() const;
 };
 
-SWIFT_NAME("getter:BridgedOStream.raw(self:)")
-inline void * _Nonnull BridgedOStream_getRaw(BridgedOStream bridged) {
-  return bridged.unbridged();
-}
-
-SWIFT_NAME("BridgedOStream.init(raw:)")
-inline BridgedOStream BridgedOStream_fromRaw(void * _Nonnull os) {
-  return static_cast<llvm::raw_ostream *>(os);
-}
-
 BridgedOStream Bridged_dbgs();
 
-//===----------------------------------------------------------------------===//
-// MARK: SourceLoc
-//===----------------------------------------------------------------------===//
-
-class BridgedSourceLoc {
-  const void *_Nullable Raw;
-
-public:
-  BridgedSourceLoc() : Raw(nullptr) {}
-
-  SWIFT_NAME("init(raw:)")
-  BridgedSourceLoc(const void *_Nullable raw) : Raw(raw) {}
-
-  BRIDGED_INLINE BridgedSourceLoc(swift::SourceLoc loc);
-
-  BRIDGED_INLINE swift::SourceLoc unbridged() const;
-
-  SWIFT_IMPORT_UNSAFE
-  const void *_Nullable getOpaquePointerValue() const { return Raw; }
-
-  SWIFT_NAME("advanced(by:)")
-  BRIDGED_INLINE
-  BridgedSourceLoc advancedBy(size_t n) const;
-};
-
-SWIFT_NAME("getter:BridgedSourceLoc.isValid(self:)")
-BRIDGED_INLINE bool BridgedSourceLoc_isValid(BridgedSourceLoc loc);
-
-//===----------------------------------------------------------------------===//
-// MARK: SourceRange
-//===----------------------------------------------------------------------===//
-
-class BridgedSourceRange {
-public:
-  SWIFT_NAME("start")
-  BridgedSourceLoc Start;
-
-  SWIFT_NAME("end")
-  BridgedSourceLoc End;
-
-  BridgedSourceRange() : Start(), End() {}
-
-  SWIFT_NAME("init(start:end:)")
-  BridgedSourceRange(BridgedSourceLoc start, BridgedSourceLoc end)
-      : Start(start), End(end) {}
-
-  BRIDGED_INLINE BridgedSourceRange(swift::SourceRange range);
-
-  BRIDGED_INLINE swift::SourceRange unbridged() const;
-};
-
-//===----------------------------------------------------------------------===//
-// MARK: BridgedCharSourceRange
-//===----------------------------------------------------------------------===//
-
-class BridgedCharSourceRange {
-public:
-  SWIFT_UNAVAILABLE("Use '.start' instead")
-  BridgedSourceLoc Start;
-
-  SWIFT_UNAVAILABLE("Use '.byteLength' instead")
-  unsigned ByteLength;
-
-  SWIFT_NAME("init(start:byteLength:)")
-  BridgedCharSourceRange(BridgedSourceLoc start, unsigned byteLength)
-      : Start(start), ByteLength(byteLength) {}
-
-  BRIDGED_INLINE BridgedCharSourceRange(swift::CharSourceRange range);
-
-  BRIDGED_INLINE swift::CharSourceRange unbridged() const;
-};
-
-SWIFT_NAME("getter:BridgedCharSourceRange.start(self:)")
-inline BridgedSourceLoc
-BridgedCharSourceRange_start(BridgedCharSourceRange range) {
-  return range.Start;
-}
-
-SWIFT_NAME("getter:BridgedCharSourceRange.byteLength(self:)")
-inline SwiftInt
-BridgedCharSourceRange_byteLength(BridgedCharSourceRange range) {
-  return static_cast<SwiftInt>(range.ByteLength);
-}
-
 //===----------------------------------------------------------------------===//
 // MARK: std::vector<BridgedCharSourceRange>
 //===----------------------------------------------------------------------===//
@@ -406,9 +334,9 @@ class BridgedCharSourceRangeVector {
   BridgedCharSourceRangeVector();
 
   SWIFT_NAME("append(_:)")
-  void push_back(BridgedCharSourceRange range);
+  void push_back(swift::CharSourceRange range);
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
   /// Returns the `std::vector<swift::CharSourceRange>` that this
   /// `BridgedCharSourceRangeVector` represents and frees the memory owned by
   /// this `BridgedCharSourceRangeVector`.
@@ -524,6 +452,84 @@ struct BridgedSwiftClosure {
   BRIDGED_INLINE void operator()(const void *_Nullable);
 };
 
+//===----------------------------------------------------------------------===//
+// MARK: LangOptions
+//===----------------------------------------------------------------------===//
+
+enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedEndianness : size_t {
+  EndianLittle,
+  EndianBig,
+};
+
+class BridgedLangOptions {
+  const swift::LangOptions * _Nonnull LangOpts;
+
+public:
+  SWIFT_UNAVAILABLE("Use init(raw:) instead")
+  BRIDGED_INLINE BridgedLangOptions(const swift::LangOptions &langOpts);
+
+  SWIFT_UNAVAILABLE("Use '.raw' instead")
+  BRIDGED_INLINE const swift::LangOptions &unbridged() const;
+
+  SWIFT_COMPUTED_PROPERTY
+  const void *_Nonnull getRaw() const { return LangOpts; }
+
+  SWIFT_COMPUTED_PROPERTY
+  unsigned getMajorLanguageVersion() const;
+
+  SWIFT_COMPUTED_PROPERTY
+  unsigned getTargetPointerBitWidth() const;
+
+  SWIFT_COMPUTED_PROPERTY
+  BridgedEndianness getTargetEndianness() const;
+
+  SWIFT_COMPUTED_PROPERTY
+  bool getAttachCommentsToDecls() const;
+};
+
+/// Key used when enumerating build configuration entries to the
+/// StaticBuildConfiguration initializer for an ASTContext.
+enum ENUM_EXTENSIBILITY_ATTR(closed) BuildConfigurationKey : size_t {
+  BCKCustomCondition,
+  BCKFeature,
+  BCKAttribute,
+  BCKTargetOSName,
+  BCKTargetArchitecture,
+  BCKTargetEnvironment,
+  BCKTargetRuntime,
+  BCKTargetPointerAuthenticationScheme,
+  BCKTargetObjectFileFormat
+};
+
+SWIFT_NAME("BridgedLangOptions.hasFeature(self:_:)")
+bool BridgedLangOptions_hasFeature(BridgedLangOptions cLangOpts,
+                                   BridgedFeature feature);
+
+SWIFT_NAME("BridgedLangOptions.getTargetAtomicBitWidths(self:_:)")
+SwiftInt BridgedLangOptions_getTargetAtomicBitWidths(BridgedLangOptions cLangOpts,
+                                                     SwiftInt* _Nullable * _Nonnull cComponents);
+
+SWIFT_NAME("BridgedLangOptions.getLanguageVersion(self:_:)")
+SwiftInt BridgedLangOptions_getLanguageVersion(BridgedLangOptions cLangOpts,
+                                               SwiftInt* _Nullable * _Nonnull cComponents);
+
+SWIFT_NAME("BridgedLangOptions.getCompilerVersion(self:_:)")
+SwiftInt BridgedLangOptions_getCompilerVersion(BridgedLangOptions cLangOpts,
+                                               SwiftInt* _Nullable * _Nonnull cComponents);
+
+/* Deallocate an array of Swift int values that was allocated in C++. */
+void deallocateIntBuffer(SwiftInt * _Nullable cComponents);
+
+/// Enumerate all of the key/value pairs for the build configuration by calling
+/// the given callback for each one.
+SWIFT_NAME("BridgedLangOptions.enumerateBuildConfigurationEntries(self:callbackContext:callback:)")
+void BridgedLangOptions_enumerateBuildConfigurationEntries(
+    BridgedLangOptions cLangOpts,
+    void * _Nonnull callbackContext,
+    void (* _Nonnull callback)(
+        BridgedLangOptions cLangOpts, void * _Nonnull callbackContext,
+        BuildConfigurationKey key, BridgedStringRef value));
+
 SWIFT_END_NULLABILITY_ANNOTATIONS
 
 #ifndef PURE_BRIDGING_MODE
diff --git a/include/swift/Basic/BasicBridgingImpl.h b/include/swift/Basic/BasicBridgingImpl.h
index 35efe357fa253..ee0474caf8a56 100644
--- a/include/swift/Basic/BasicBridgingImpl.h
+++ b/include/swift/Basic/BasicBridgingImpl.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2023 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -14,38 +14,11 @@
 #define SWIFT_BASIC_BASICBRIDGINGIMPL_H
 
 #include "swift/Basic/Assertions.h"
-#include "swift/Basic/SourceLoc.h"
 #include "llvm/ADT/StringRef.h"
 
 SWIFT_BEGIN_NULLABILITY_ANNOTATIONS
 
-//===----------------------------------------------------------------------===//
-// MARK: BridgedArrayRef
-//===----------------------------------------------------------------------===//
-
-const void *_Nullable BridgedArrayRef_data(BridgedArrayRef arr) {
-  return arr.Data;
-}
-
-SwiftInt BridgedArrayRef_count(BridgedArrayRef arr) {
-  return static_cast<SwiftInt>(arr.Length);
-}
-
-bool BridgedArrayRef_isEmpty(BridgedArrayRef arr) {
-  return arr.Length == 0;
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: BridgedData
-//===----------------------------------------------------------------------===//
-
-const char *_Nullable BridgedData_baseAddress(BridgedData data) {
-  return data.BaseAddress;
-}
-
-SwiftInt BridgedData_count(BridgedData data) {
-  return static_cast<SwiftInt>(data.Length);
-}
+void ASSERT_inBridgingHeader(bool condition) { ASSERT(condition); }
 
 //===----------------------------------------------------------------------===//
 // MARK: BridgedStringRef
@@ -58,79 +31,12 @@ llvm::StringRef BridgedStringRef::unbridged() const {
   return llvm::StringRef(Data, Length);
 }
 
-const uint8_t *_Nullable BridgedStringRef_data(BridgedStringRef str) {
-  return (const uint8_t *)str.unbridged().data();
-}
-
-SwiftInt BridgedStringRef_count(BridgedStringRef str) {
-  return (SwiftInt)str.unbridged().size();
-}
-
-bool BridgedStringRef_empty(BridgedStringRef str) {
-  return str.unbridged().empty();
-}
-
 //===----------------------------------------------------------------------===//
 // MARK: BridgedOwnedString
 //===----------------------------------------------------------------------===//
 
 llvm::StringRef BridgedOwnedString::unbridgedRef() const { return llvm::StringRef(Data, Length); }
 
-const uint8_t *_Nullable BridgedOwnedString_data(BridgedOwnedString str) {
-  auto *data = str.unbridgedRef().data();
-  return (const uint8_t *)(data ? data : "");
-}
-
-SwiftInt BridgedOwnedString_count(BridgedOwnedString str) {
-  return (SwiftInt)str.unbridgedRef().size();
-}
-
-bool BridgedOwnedString_empty(BridgedOwnedString str) {
-  return str.unbridgedRef().empty();
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: BridgedSourceLoc
-//===----------------------------------------------------------------------===//
-
-BridgedSourceLoc::BridgedSourceLoc(swift::SourceLoc loc)
-  : Raw(loc.getOpaquePointerValue()) {}
-
-swift::SourceLoc BridgedSourceLoc::unbridged() const {
-  return swift::SourceLoc(
-      llvm::SMLoc::getFromPointer(static_cast<const char *>(Raw)));
-}
-
-bool BridgedSourceLoc_isValid(BridgedSourceLoc loc) {
-  return loc.getOpaquePointerValue() != nullptr;
-}
-
-BridgedSourceLoc BridgedSourceLoc::advancedBy(size_t n) const {
-  return BridgedSourceLoc(unbridged().getAdvancedLoc(n));
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: BridgedSourceRange
-//===----------------------------------------------------------------------===//
-
-BridgedSourceRange::BridgedSourceRange(swift::SourceRange range)
-    : Start(range.Start), End(range.End) {}
-
-swift::SourceRange BridgedSourceRange::unbridged() const {
-  return swift::SourceRange(Start.unbridged(), End.unbridged());
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: BridgedCharSourceRange
-//===----------------------------------------------------------------------===//
-
-BridgedCharSourceRange::BridgedCharSourceRange(swift::CharSourceRange range)
-    : Start(range.getStart()), ByteLength(range.getByteLength()) {}
-
-swift::CharSourceRange BridgedCharSourceRange::unbridged() const {
-  return swift::CharSourceRange(Start.unbridged(), ByteLength);
-}
-
 //===----------------------------------------------------------------------===//
 // MARK: BridgedSwiftVersion
 //===----------------------------------------------------------------------===//
@@ -146,7 +52,11 @@ swift_ASTGen_bridgedSwiftClosureCall_1(const void *_Nonnull closure,
                                        const void *_Nullable arg1);
 
 void BridgedSwiftClosure::operator()(const void *_Nullable arg1) {
+#if SWIFT_BUILD_SWIFT_SYNTAX
   swift_ASTGen_bridgedSwiftClosureCall_1(closure, arg1);
+#else
+  llvm_unreachable("Must not be used in C++-only build");
+#endif
 }
 
 SWIFT_END_NULLABILITY_ANNOTATIONS
diff --git a/include/swift/Basic/BlockListAction.def b/include/swift/Basic/BlockListAction.def
index 8d9839f019ce3..ffa570e27272f 100644
--- a/include/swift/Basic/BlockListAction.def
+++ b/include/swift/Basic/BlockListAction.def
@@ -26,5 +26,6 @@ BLOCKLIST_ACTION(ShouldUseLayoutStringValueWitnesses)
 BLOCKLIST_ACTION(ShouldDisableOwnershipVerification)
 BLOCKLIST_ACTION(SkipEmittingFineModuleTrace)
 BLOCKLIST_ACTION(SkipIndexingModule)
+BLOCKLIST_ACTION(ShouldUseTypeCheckerPerfHacks)
 
 #undef BLOCKLIST_ACTION
diff --git a/include/swift/Basic/CASOptions.h b/include/swift/Basic/CASOptions.h
index fb63938e1f3fb..567c34671fc49 100644
--- a/include/swift/Basic/CASOptions.h
+++ b/include/swift/Basic/CASOptions.h
@@ -34,17 +34,17 @@ class CASOptions final {
   /// Skip replaying outputs from cache.
   bool CacheSkipReplay = false;
 
+  /// Import modules from CAS.
+  bool ImportModuleFromCAS = false;
+
   /// CASOptions
   clang::CASOptions CASOpts;
 
-  /// CASFS Root.
-  std::vector<std::string> CASFSRootIDs;
-
   /// Clang Include Trees.
-  std::vector<std::string> ClangIncludeTrees;
+  std::string ClangIncludeTree;
 
   /// Clang Include Tree FileList.
-  std::vector<std::string> ClangIncludeTreeFileList;
+  std::string ClangIncludeTreeFileList;
 
   /// CacheKey for input file.
   std::string InputFileKey;
@@ -62,9 +62,8 @@ class CASOptions final {
   /// Check to see if a CASFileSystem is required.
   bool requireCASFS() const {
     return EnableCaching &&
-           (!CASFSRootIDs.empty() || !ClangIncludeTrees.empty() ||
-            !ClangIncludeTreeFileList.empty() || !InputFileKey.empty() ||
-            !BridgingHeaderPCHCacheKey.empty());
+           (!ClangIncludeTree.empty() || !ClangIncludeTreeFileList.empty() ||
+            !InputFileKey.empty() || !BridgingHeaderPCHCacheKey.empty());
   }
 
   /// Return a hash code of any components from these options that should
diff --git a/include/swift/Basic/Casting.h b/include/swift/Basic/Casting.h
new file mode 100644
index 0000000000000..85ffe8f0ae6ac
--- /dev/null
+++ b/include/swift/Basic/Casting.h
@@ -0,0 +1,59 @@
+//===--- Casting.h - Helpers for casting ------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_BASIC_CASTING_H
+#define SWIFT_BASIC_CASTING_H
+
+#include <type_traits>
+
+namespace swift {
+
+/// Cast between two function types. Use in place of std::bit_cast, which
+/// doesn't work on ARM64e with address-discriminated signed function types.
+///
+/// Address-discriminated ptrauth attributes can only be applied to values with
+/// a defined storage location, such as struct fields, since their value is
+/// inherently tied to their address. They can't be applied to function
+/// paremeters. When passing such a value to a templated function, the ptrauth
+/// attribute disappears from the inferred type.
+///
+/// bit_cast takes the source by reference, which means that the ptrauth
+/// attribute remains on the inferred type, and the value is not trivially
+/// copyable.
+///
+/// function_cast instead takes the source by value, avoiding that issue and
+/// ensuring that passed-in function pointers are always trivially copyable.
+template <typename Destination, typename Source>
+Destination function_cast(Source source) {
+  static_assert(sizeof(Destination) == sizeof(Source),
+                "Source and destination must be the same size");
+  static_assert(std::is_trivially_copyable_v<Source>,
+                "The source type must be trivially constructible");
+  static_assert(std::is_trivially_copyable_v<Destination>,
+                "The destination type must be trivially constructible");
+
+#if __has_feature(ptrauth_calls)
+  // Use reinterpret_cast here so we perform any necessary auth-and-sign.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wcast-function-type-mismatch"
+  return reinterpret_cast<Destination>(source);
+#pragma clang diagnostic pop
+#else
+  Destination destination;
+  memcpy(&destination, &source, sizeof(source));
+  return destination;
+#endif
+}
+
+}
+
+#endif
diff --git a/include/swift/Basic/Compiler.h b/include/swift/Basic/Compiler.h
index 97562a24dcc38..5b057c3d62289 100644
--- a/include/swift/Basic/Compiler.h
+++ b/include/swift/Basic/Compiler.h
@@ -90,13 +90,6 @@
 #define SWIFT_IMPORT_UNSAFE
 #endif
 
-/// Same as `SWIFT_SELF_CONTAINED` in <swift/bridging>.
-#if __has_attribute(swift_attr)
-#define SWIFT_SELF_CONTAINED __attribute__((swift_attr("import_owned")))
-#else
-#define SWIFT_SELF_CONTAINED
-#endif
-
 #ifdef __GNUC__
 #define SWIFT_ATTRIBUTE_NORETURN __attribute__((noreturn))
 #elif defined(_MSC_VER)
@@ -197,4 +190,10 @@ inline const char *operator""_swift_u8(const char8_t *p, size_t) {
 #endif // defined(__cpp_char8_t)
 #endif // defined(__cplusplus)
 
+#if __has_attribute(trivial_abi)
+#define SWIFT_TRIVIAL_ABI __attribute__((trivial_abi))
+#else
+#define SWIFT_TRIVIAL_ABI
+#endif
+
 #endif // SWIFT_BASIC_COMPILER_H
diff --git a/include/swift/Basic/DiagnosticOptions.h b/include/swift/Basic/DiagnosticOptions.h
index 2be70d7e1a43a..356cbebfe6ad4 100644
--- a/include/swift/Basic/DiagnosticOptions.h
+++ b/include/swift/Basic/DiagnosticOptions.h
@@ -41,6 +41,11 @@ class DiagnosticOptions {
   /// \c VerifyMode is not \c NoVerify.
   bool VerifyIgnoreUnknown = false;
 
+  /// Indicates whether to allow diagnostics for locations outside files parsed
+  /// for 'expected' diagnostics if \c VerifyMode is not \c NoVerify. Does not
+  /// allow diagnostics at <unknown>, that is controlled by VerifyIgnoreUnknown.
+  bool VerifyIgnoreUnrelated = false;
+
   /// Indicates whether diagnostic passes should be skipped.
   bool SkipDiagnosticPasses = false;
 
@@ -58,6 +63,9 @@ class DiagnosticOptions {
   /// Suppress all warnings
   bool SuppressWarnings = false;
   
+  /// Suppress all notes
+  bool SuppressNotes = false;
+
   /// Suppress all remarks
   bool SuppressRemarks = false;
 
diff --git a/include/swift/Basic/EncodedSequence.h b/include/swift/Basic/EncodedSequence.h
index 8b041731d5de3..81b5bc5ad32ec 100644
--- a/include/swift/Basic/EncodedSequence.h
+++ b/include/swift/Basic/EncodedSequence.h
@@ -102,14 +102,12 @@ class EncodedSequenceBase {
     }
 
     MutableArrayRef<Chunk> chunkStorage() {
-      return {getTrailingObjects<Chunk>(), Capacity};
+      return getTrailingObjects(Capacity);
     }
     ArrayRef<Chunk> chunkStorage() const {
-      return {getTrailingObjects<Chunk>(), Capacity};
-    }
-    ArrayRef<Chunk> chunks() const {
-      return {getTrailingObjects<Chunk>(), Size};
+      return getTrailingObjects(Capacity);
     }
+    ArrayRef<Chunk> chunks() const { return getTrailingObjects(Size); }
   };
   OutOfLineStorage *getOutOfLineStorage() {
     assert(hasOutOfLineStorage());
diff --git a/include/swift/Basic/Feature.h b/include/swift/Basic/Feature.h
index d0727bd239efe..b05080bbf3a86 100644
--- a/include/swift/Basic/Feature.h
+++ b/include/swift/Basic/Feature.h
@@ -10,8 +10,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef SWIFT_BASIC_FEATURES_H
-#define SWIFT_BASIC_FEATURES_H
+#ifndef SWIFT_BASIC_FEATURE_H
+#define SWIFT_BASIC_FEATURE_H
+
+#include "swift/Basic/LLVM.h"
 
 #include "llvm/ADT/StringRef.h"
 #include <optional>
@@ -21,53 +23,72 @@ namespace swift {
 class LangOptions;
 
 /// Enumeration describing all of the named features.
-enum class Feature : uint16_t {
+struct Feature {
+  enum class InnerKind : uint16_t {
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description) FeatureName,
 #include "swift/Basic/Features.def"
-};
+  };
+
+  InnerKind kind;
 
-constexpr unsigned numFeatures() {
-  enum Features {
+  constexpr Feature(InnerKind kind) : kind(kind) {}
+  constexpr Feature(unsigned inputKind) : kind(InnerKind(inputKind)) {}
+
+  constexpr operator InnerKind() const { return kind; }
+  constexpr explicit operator unsigned() const { return unsigned(kind); }
+  constexpr explicit operator size_t() const { return size_t(kind); }
+
+  static constexpr unsigned getNumFeatures() {
+    enum Features {
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description) FeatureName,
 #include "swift/Basic/Features.def"
-    NumFeatures
-  };
-  return NumFeatures;
-}
+      NumFeatures
+    };
+    return NumFeatures;
+  }
 
-/// Check whether the given feature is available in production compilers.
-bool isFeatureAvailableInProduction(Feature feature);
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
+  static const Feature FeatureName;
+#include "swift/Basic/Features.def"
 
-/// Determine the in-source name of the given feature.
-llvm::StringRef getFeatureName(Feature feature);
+  /// Check whether the given feature is available in production compilers.
+  bool isAvailableInProduction() const;
 
-/// Determine whether the first feature is more recent (and thus implies
-/// the existence of) the second feature.  Only meaningful for suppressible
-/// features.
-inline bool featureImpliesFeature(Feature feature, Feature implied) {
-  // Suppressible features are expected to be listed in order of
-  // addition in Features.def.
-  return (unsigned) feature < (unsigned) implied;
-}
+  /// Determine the in-source name of the given feature.
+  llvm::StringRef getName() const;
 
-/// Get the feature corresponding to this "future" feature, if there is one.
-std::optional<Feature> getUpcomingFeature(llvm::StringRef name);
+  /// Determine whether the given feature supports migration mode.
+  bool isMigratable() const;
 
-/// Get the feature corresponding to this "experimental" feature, if there is
-/// one.
-std::optional<Feature> getExperimentalFeature(llvm::StringRef name);
+  /// Determine whether this feature should be included in the
+  /// module interface
+  bool includeInModuleInterface() const;
 
-/// Get the major language version in which this feature was introduced, or
-/// \c None if it does not have such a version.
-std::optional<unsigned> getFeatureLanguageVersion(Feature feature);
+  /// Determine whether the first feature is more recent (and thus implies
+  /// the existence of) the second feature.  Only meaningful for suppressible
+  /// features.
+  constexpr bool featureImpliesFeature(Feature implied) const {
+    // Suppressible features are expected to be listed in order of
+    // addition in Features.def.
+    return (unsigned)kind < (unsigned)implied.kind;
+  }
 
-/// Determine whether the given feature supports adoption mode.
-bool isFeatureAdoptable(Feature feature);
+  /// Get the feature corresponding to this "future" feature, if there is one.
+  static std::optional<Feature> getUpcomingFeature(StringRef name);
 
-/// Determine whether this feature should be included in the
-/// module interface
-bool includeInModuleInterface(Feature feature);
+  /// Get the feature corresponding to this "experimental" feature, if there is
+  /// one.
+  static std::optional<Feature> getExperimentalFeature(StringRef name);
 
+  /// Get the major language version in which this feature was introduced, or
+  /// \c None if it does not have such a version.
+  std::optional<unsigned> getLanguageVersion() const;
+};
+
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
+  constexpr inline Feature Feature::FeatureName =                              \
+      Feature::InnerKind::FeatureName;
+#include "swift/Basic/Features.def"
 }
 
 #endif // SWIFT_BASIC_FEATURES_H
diff --git a/include/swift/Basic/Features.def b/include/swift/Basic/Features.def
index 2f889e2fefc7b..defc01e490be8 100644
--- a/include/swift/Basic/Features.def
+++ b/include/swift/Basic/Features.def
@@ -121,40 +121,45 @@
     LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #endif
 
-// An upcoming feature that supports adoption mode.
+// An upcoming feature that supports migration mode.
 //
 // If the feature is source-breaking and provides for a
-// mechanical code migration, it should implement adoption mode.
+// mechanical code migration, it should implement migration mode.
 //
-// Adoption mode is a feature-oriented code migration mechanism: a mode
+// Migration mode is a feature-oriented code migration mechanism: a mode
 // of operation that should produce compiler warnings with attached
 // fix-its that can be applied to preserve the behavior of the code once
 // the upcoming feature is enacted.
 // These warnings must belong to a diagnostic group named after the
-// feature. Adoption mode itself *and* the fix-its it produces must be
+// feature. Migration mode itself *and* the fix-its it produces must be
 // source and binary compatible with how the code is compiled when the
 // feature is disabled.
-#ifndef ADOPTABLE_UPCOMING_FEATURE
+#ifndef MIGRATABLE_UPCOMING_FEATURE
   #if defined(UPCOMING_FEATURE)
-    #define ADOPTABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)         \
+    #define MIGRATABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)         \
       UPCOMING_FEATURE(FeatureName, SENumber, Version)
   #else
-    #define ADOPTABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)         \
+    #define MIGRATABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)         \
       LANGUAGE_FEATURE(FeatureName, SENumber, #FeatureName)
   #endif
 #endif
 
-// See `ADOPTABLE_UPCOMING_FEATURE`.
-#ifndef ADOPTABLE_EXPERIMENTAL_FEATURE
+// See `MIGRATABLE_UPCOMING_FEATURE`.
+#ifndef MIGRATABLE_EXPERIMENTAL_FEATURE
   #if defined(EXPERIMENTAL_FEATURE)
-    #define ADOPTABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)       \
+    #define MIGRATABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)       \
       EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)
   #else
-    #define ADOPTABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)       \
+    #define MIGRATABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)       \
       LANGUAGE_FEATURE(FeatureName, 0, #FeatureName)
   #endif
 #endif
 
+#ifndef MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE
+  #define MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Name)   \
+      OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, #Name)
+#endif
+
 #ifndef UPCOMING_FEATURE
   #define UPCOMING_FEATURE(FeatureName, SENumber, Version)                     \
     LANGUAGE_FEATURE(FeatureName, SENumber, #FeatureName)
@@ -241,19 +246,36 @@ BASELINE_LANGUAGE_FEATURE(BitwiseCopyable, 426, "BitwiseCopyable protocol")
 BASELINE_LANGUAGE_FEATURE(NoncopyableGenerics, 427, "Noncopyable generics")
 BASELINE_LANGUAGE_FEATURE(NoncopyableGenerics2, 427, "Noncopyable generics alias")
 BASELINE_LANGUAGE_FEATURE(ConformanceSuppression, 426, "Suppressible inferred conformances")
-SUPPRESSIBLE_LANGUAGE_FEATURE(BitwiseCopyable2, 426, "BitwiseCopyable feature")
+BASELINE_LANGUAGE_FEATURE(BitwiseCopyable2, 426, "BitwiseCopyable feature")
 BASELINE_LANGUAGE_FEATURE(BodyMacros, 415, "Function body macros")
-SUPPRESSIBLE_LANGUAGE_FEATURE(SendingArgsAndResults, 430, "Sending arg and results")
+LANGUAGE_FEATURE(SendingArgsAndResults, 430, "Sending arg and results")
 BASELINE_LANGUAGE_FEATURE(BorrowingSwitch, 432, "Noncopyable type pattern matching")
-CONDITIONALLY_SUPPRESSIBLE_LANGUAGE_FEATURE(IsolatedAny, 431, "@isolated(any) function types")
+BASELINE_LANGUAGE_FEATURE(IsolatedAny, 431, "@isolated(any) function types")
 LANGUAGE_FEATURE(IsolatedAny2, 431, "@isolated(any) function types")
 LANGUAGE_FEATURE(ObjCImplementation, 436, "@objc @implementation extensions")
-LANGUAGE_FEATURE(NonescapableTypes, 446, "Nonescapable types")
-LANGUAGE_FEATURE(BuiltinEmplaceTypedThrows, 0, "Builtin.emplace typed throws")
-SUPPRESSIBLE_LANGUAGE_FEATURE(MemorySafetyAttributes, 458, "@unsafe attribute")
-LANGUAGE_FEATURE(ValueGenerics, 452, "Value generics feature (integer generics)")
+BASELINE_LANGUAGE_FEATURE(NonescapableTypes, 446, "Nonescapable types")
+BASELINE_LANGUAGE_FEATURE(BuiltinEmplaceTypedThrows, 0, "Builtin.emplace typed throws")
+BASELINE_LANGUAGE_FEATURE(MemorySafetyAttributes, 458, "@unsafe attribute")
+BASELINE_LANGUAGE_FEATURE(ValueGenerics, 452, "Value generics feature (integer generics)")
 LANGUAGE_FEATURE(RawIdentifiers, 451, "Raw identifiers")
 LANGUAGE_FEATURE(SendableCompletionHandlers, 463, "Objective-C completion handler parameters are imported as @Sendable")
+LANGUAGE_FEATURE(AsyncExecutionBehaviorAttributes, 0, "@concurrent and nonisolated(nonsending)")
+LANGUAGE_FEATURE(IsolatedConformances, 407, "Global-actor isolated conformances")
+BASELINE_LANGUAGE_FEATURE(ValueGenericsNameLookup, 452, "Value generics appearing as static members for namelookup")
+LANGUAGE_FEATURE(GeneralizedIsSameMetaTypeBuiltin, 465, "Builtin.is_same_metatype with support for noncopyable/nonescapable types")
+SUPPRESSIBLE_LANGUAGE_FEATURE(ABIAttributeSE0479, 479, "@abi attribute on functions, initializers, properties, and subscripts")
+LANGUAGE_FEATURE(AlwaysInheritActorContext, 472, "@_inheritActorContext(always)")
+LANGUAGE_FEATURE(BuiltinSelect, 0, "Builtin.select")
+LANGUAGE_FEATURE(BuiltinInterleave, 0, "Builtin.interleave and Builtin.deinterleave")
+LANGUAGE_FEATURE(BuiltinVectorsExternC, 0, "Extern C support for Builtin vector types")
+LANGUAGE_FEATURE(AddressOfProperty2, 0, "Builtin.unprotectedAddressOf properties")
+LANGUAGE_FEATURE(NonescapableAccessorOnTrivial, 0, "Support UnsafeMutablePointer.mutableSpan")
+BASELINE_LANGUAGE_FEATURE(LayoutPrespecialization, 0, "Layout pre-specialization")
+BASELINE_LANGUAGE_FEATURE(IsolatedDeinit, 371, "isolated deinit")
+LANGUAGE_FEATURE(InlineArrayTypeSugar, 483, "Type sugar for InlineArray")
+LANGUAGE_FEATURE(LifetimeDependenceMutableAccessors, 0, "Support mutable accessors returning ~Escapable results")
+LANGUAGE_FEATURE(InoutLifetimeDependence, 0, "Support @_lifetime(&)")
+SUPPRESSIBLE_LANGUAGE_FEATURE(NonexhaustiveAttribute, 487, "Nonexhaustive Enums")
 
 // Swift 6
 UPCOMING_FEATURE(ConciseMagicFile, 274, 6)
@@ -273,15 +295,20 @@ UPCOMING_FEATURE(NonfrozenEnumExhaustivity, 192, 6)
 UPCOMING_FEATURE(GlobalActorIsolatedTypesUsability, 0434, 6)
 
 // Swift 7
-ADOPTABLE_UPCOMING_FEATURE(ExistentialAny, 335, 7)
+MIGRATABLE_UPCOMING_FEATURE(ExistentialAny, 335, 7)
 UPCOMING_FEATURE(InternalImportsByDefault, 409, 7)
-UPCOMING_FEATURE(MemberImportVisibility, 444, 7)
+MIGRATABLE_UPCOMING_FEATURE(MemberImportVisibility, 444, 7)
+MIGRATABLE_UPCOMING_FEATURE(InferIsolatedConformances, 470, 7)
+MIGRATABLE_UPCOMING_FEATURE(NonisolatedNonsendingByDefault, 461, 7)
+UPCOMING_FEATURE(ImmutableWeakCaptures, 481, 7)
 
 // Optional language features / modes
 
 /// Diagnose uses of language constructs and APIs that can violate memory
 /// safety.
-OPTIONAL_LANGUAGE_FEATURE(StrictMemorySafety, 458, "Strict memory safety")
+MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(StrictMemorySafety, 458, "Strict memory safety")
+
+OPTIONAL_LANGUAGE_FEATURE(LibraryEvolution, 0, "Library evolution")
 
 // Experimental features
 
@@ -299,6 +326,12 @@ EXPERIMENTAL_FEATURE(KeyPathWithMethodMembers, false)
 // Whether to enable @_used and @_section attributes
 EXPERIMENTAL_FEATURE(SymbolLinkageMarkers, true)
 
+// Whether to emit an Embedded Swift module with "deferred" code generation,
+// meaning that the only code that will be emitted into the object file is
+// code that was marked as "never emit into client". For everything else,
+// Swift still store the SIL and emit it into the client only when used.
+EXPERIMENTAL_FEATURE(DeferredCodeGen, true)
+
 // Whether to compile scripts lazily in immediate mode
 EXPERIMENTAL_FEATURE(LazyImmediate, false)
 
@@ -313,10 +346,12 @@ EXPERIMENTAL_FEATURE(MoveOnlyTuples, true)
 EXPERIMENTAL_FEATURE(MoveOnlyPartialReinitialization, true)
 EXPERIMENTAL_FEATURE(ConsumeSelfInDeinit, true)
 
-EXPERIMENTAL_FEATURE(LayoutPrespecialization, true)
-
 EXPERIMENTAL_FEATURE(AccessLevelOnImport, true)
 
+/// Disable the special behavior of of explicit 'nonisolated' vs. being
+/// implicitly nonisolated.
+EXPERIMENTAL_FEATURE(NoExplicitNonIsolated, true)
+
 /// Enables a module to allow non resilient access from other
 /// modules within a package if built from source.
 EXPERIMENTAL_FEATURE(AllowNonResilientAccessInPackage, false)
@@ -370,11 +405,6 @@ EXPERIMENTAL_FEATURE(ParserASTGen, false)
 /// corresponding syntax tree.
 EXPERIMENTAL_FEATURE(BuiltinMacros, false)
 
-/// Import C++ class templates as semantically-meaningless symbolic
-/// Swift types and C++ methods as symbolic functions with blank
-/// signatures.
-EXPERIMENTAL_FEATURE(ImportSymbolicCXXDecls, false)
-
 /// Generate bindings for functions that 'throw' in the C++ section of the generated Clang header.
 EXPERIMENTAL_FEATURE(GenerateBindingsForThrowingFunctionsInCXX, false)
 
@@ -394,6 +424,9 @@ EXPERIMENTAL_FEATURE(ThenStatements, false)
 /// Enable 'do' expressions.
 EXPERIMENTAL_FEATURE(DoExpressions, false)
 
+/// Enable 'for' expressions.
+EXPERIMENTAL_FEATURE(ForExpressions, false)
+
 /// Enable implicitly treating the last expression in a function, closure,
 /// and 'if'/'switch' expression as the result.
 EXPERIMENTAL_FEATURE(ImplicitLastExprResults, false)
@@ -419,6 +452,9 @@ EXPERIMENTAL_FEATURE(LifetimeDependence, true)
 /// Enable the `@_staticExclusiveOnly` attribute.
 EXPERIMENTAL_FEATURE(StaticExclusiveOnly, true)
 
+/// Enable the `@_manualOwnership` attribute.
+EXPERIMENTAL_FEATURE(ManualOwnership, false)
+
 /// Enable the @extractConstantsFromMembers attribute.
 EXPERIMENTAL_FEATURE(ExtractConstantsFromMembers, false)
 
@@ -454,7 +490,7 @@ EXPERIMENTAL_FEATURE(TrailingComma, false)
 
 // Import bounds safety and lifetime attributes from interop headers to
 // generate Swift wrappers with safe pointer types.
-EXPERIMENTAL_FEATURE(SafeInteropWrappers, false)
+EXPERIMENTAL_FEATURE(SafeInteropWrappers, true)
 
 /// Ignore resilience errors due to C++ types.
 EXPERIMENTAL_FEATURE(AssumeResilientCxxTypes, true)
@@ -462,12 +498,14 @@ EXPERIMENTAL_FEATURE(AssumeResilientCxxTypes, true)
 /// Import inherited non-public members when importing C++ classes.
 EXPERIMENTAL_FEATURE(ImportNonPublicCxxMembers, true)
 
-/// Synthesize static factory methods for C++ foreign reference types and import
-/// them as Swift initializers.
-EXPERIMENTAL_FEATURE(CXXForeignReferenceTypeInitializers, true)
+/// Suppress the synthesis of static factory methods for C++ foreign reference
+/// types and importing them as Swift initializers.
+EXPERIMENTAL_FEATURE(SuppressCXXForeignReferenceTypeInitializers, true)
 
-// Isolated deinit
-SUPPRESSIBLE_LANGUAGE_FEATURE(IsolatedDeinit, 371, "isolated deinit")
+/// Emit a warning when a C++ API returns a SWIFT_SHARED_REFERENCE type
+/// without being explicitly annotated with either SWIFT_RETURNS_RETAINED
+/// or SWIFT_RETURNS_UNRETAINED.
+EXPERIMENTAL_FEATURE(WarnUnannotatedReturnOfCxxFrt, true)
 
 /// modify/read single-yield coroutines
 SUPPRESSIBLE_EXPERIMENTAL_FEATURE(CoroutineAccessors, true)
@@ -478,54 +516,55 @@ EXPERIMENTAL_FEATURE(CoroutineAccessorsUnwindOnCallerError, false)
 EXPERIMENTAL_FEATURE(AddressableParameters, true)
 SUPPRESSIBLE_EXPERIMENTAL_FEATURE(AddressableTypes, true)
 
-/// Allow the @abi attribute.
-SUPPRESSIBLE_EXPERIMENTAL_FEATURE(ABIAttribute, true)
-
-/// Allow the @execution attribute. This is also connected to
-/// AsyncCallerExecution feature.
-SUPPRESSIBLE_EXPERIMENTAL_FEATURE(ExecutionAttribute, false)
-
-/// Functions with nonisolated isolation inherit their isolation from the
-/// calling context.
-ADOPTABLE_EXPERIMENTAL_FEATURE(AsyncCallerExecution, false)
-
 /// Allow custom availability domains to be defined and referenced.
-SUPPRESSIBLE_EXPERIMENTAL_FEATURE(CustomAvailability, true)
-
-/// Allow public enumerations to be extensible by default
-/// regardless of whether the module they are declared in
-/// is resilient or not.
-EXPERIMENTAL_FEATURE(ExtensibleEnums, true)
-
-/// Allow isolated conformances.
-EXPERIMENTAL_FEATURE(IsolatedConformances, true)
-
-/// Infer conformance isolation on global-actor-conforming types.
-EXPERIMENTAL_FEATURE(InferIsolatedConformances, true)
-
-/// Allow SwiftSettings
-EXPERIMENTAL_FEATURE(SwiftSettings, false)
+EXPERIMENTAL_FEATURE(CustomAvailability, true)
 
 /// Syntax sugar features for concurrency.
 EXPERIMENTAL_FEATURE(ConcurrencySyntaxSugar, true)
 
-/// Enable syntax sugar type '[3 x Int]' for Inline Array
-EXPERIMENTAL_FEATURE(InlineArrayTypeSugar, false)
-
 /// Allow declaration of compile-time values
 EXPERIMENTAL_FEATURE(CompileTimeValues, true)
 
+/// Allow declaration of compile-time values
+EXPERIMENTAL_FEATURE(CompileTimeValuesPreview, false)
+
 /// Allow function body macros applied to closures.
 EXPERIMENTAL_FEATURE(ClosureBodyMacro, true)
 
 /// Allow declarations of Swift runtime symbols using @_silgen_name.
 EXPERIMENTAL_FEATURE(AllowRuntimeSymbolDeclarations, true)
 
+/// Allow use of `@c`
+EXPERIMENTAL_FEATURE(CDecl, false)
+
+/// Allow use of `Module::name` syntax
+EXPERIMENTAL_FEATURE(ModuleSelector, false)
+
+/// Allow use of `using` declaration that control default isolation
+/// in a file scope.
+EXPERIMENTAL_FEATURE(DefaultIsolationPerFile, false)
+
+/// Enable @_lifetime attribute
+SUPPRESSIBLE_EXPERIMENTAL_FEATURE(Lifetimes, true)
+
+/// Allow macro based aliases to be imported into Swift
+EXPERIMENTAL_FEATURE(ImportMacroAliases, true)
+
+/// Enable borrow/mutate accessors
+EXPERIMENTAL_FEATURE(BorrowAndMutateAccessors, false)
+
+/// Allow use of @inline(always) attribute
+SUPPRESSIBLE_EXPERIMENTAL_FEATURE(InlineAlways, false)
+
+/// Allow use of 'Swift' (Swift runtime version) in @available attributes
+EXPERIMENTAL_FEATURE(SwiftRuntimeAvailability, true)
+
 #undef EXPERIMENTAL_FEATURE_EXCLUDED_FROM_MODULE_INTERFACE
 #undef EXPERIMENTAL_FEATURE
 #undef UPCOMING_FEATURE
-#undef ADOPTABLE_UPCOMING_FEATURE
-#undef ADOPTABLE_EXPERIMENTAL_FEATURE
+#undef MIGRATABLE_UPCOMING_FEATURE
+#undef MIGRATABLE_EXPERIMENTAL_FEATURE
+#undef MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE
 #undef BASELINE_LANGUAGE_FEATURE
 #undef OPTIONAL_LANGUAGE_FEATURE
 #undef CONDITIONALLY_SUPPRESSIBLE_EXPERIMENTAL_FEATURE
diff --git a/include/swift/Basic/FileTypes.def b/include/swift/Basic/FileTypes.def
index ae18991130eca..4ca4c87520b20 100644
--- a/include/swift/Basic/FileTypes.def
+++ b/include/swift/Basic/FileTypes.def
@@ -78,8 +78,8 @@ TYPE("fine-module-trace",   FineModuleTrace,           "",                "")
 // Complete dependency information for the given Swift files as JSON.
 TYPE("json-dependencies",   JSONDependencies,          "dependencies.json",      "")
 
-// Complete feature information for the given Swift compiler.
-TYPE("json-features",       JSONFeatures,              "features.json",   "")
+// Complete supported argument information for the given Swift compiler.
+TYPE("json-arguments",      JSONArguments,            "arguments.json",   "")
 
 // Gathered compile-time-known value information for the given Swift input file as JSON.
 TYPE("const-values",       ConstValues,              "swiftconstvalues",   "")
diff --git a/include/swift/Basic/InlineBitfield.h b/include/swift/Basic/InlineBitfield.h
index b41ae018d4edf..1378115aee012 100644
--- a/include/swift/Basic/InlineBitfield.h
+++ b/include/swift/Basic/InlineBitfield.h
@@ -41,7 +41,7 @@ namespace swift {
     uint64_t : 64 - (C); /* Better code gen */ \
   } T; \
   LLVM_PACKED_END \
-  enum { Num##T##Bits = (C) }; \
+  enum { NumberOf##T##Bits = (C) }; \
   static_assert(sizeof(T##Bitfield) <= 8, "Bitfield overflow")
 
 /// Define an bitfield for type 'T' with parent class 'U' and 'C' bits used.
@@ -49,11 +49,11 @@ namespace swift {
   LLVM_PACKED_START \
   class T##Bitfield { \
     friend class T; \
-    uint64_t : Num##U##Bits, __VA_ARGS__; \
-    uint64_t : 64 - (Num##U##Bits + (HC) + (C)); /* Better code gen */ \
+    uint64_t : NumberOf##U##Bits, __VA_ARGS__; \
+    uint64_t : 64 - (NumberOf##U##Bits + (HC) + (C)); /* Better code gen */ \
   } T; \
   LLVM_PACKED_END \
-  enum { Num##T##Bits = Num##U##Bits + (C) }; \
+  enum { NumberOf##T##Bits = NumberOf##U##Bits + (C) }; \
   static_assert(sizeof(T##Bitfield) <= 8, "Bitfield overflow")
 
 #define SWIFT_INLINE_BITFIELD(T, U, C, ...) \
@@ -75,8 +75,8 @@ namespace swift {
   LLVM_PACKED_START \
   class T##Bitfield { \
     friend class T; \
-    enum { NumPadBits = 64 - (Num##U##Bits + (C)) }; \
-    uint64_t : Num##U##Bits, __VA_ARGS__; \
+    enum { NumPadBits = 64 - (NumberOf##U##Bits + (C)) }; \
+    uint64_t : NumberOf##U##Bits, __VA_ARGS__; \
   } T; \
   LLVM_PACKED_END \
   static_assert(sizeof(T##Bitfield) <= 8, "Bitfield overflow")
@@ -101,15 +101,15 @@ namespace swift {
   class T##Bitfield {                                                          \
     template <typename TTy>                                                    \
     friend class T;                                                            \
-    enum { NumPadBits = 64 - (Num##U##Bits + (C)) };                           \
-    uint64_t : Num##U##Bits, __VA_ARGS__;                                      \
+    enum { NumPadBits = 64 - (NumberOf##U##Bits + (C)) };                      \
+    uint64_t : NumberOf##U##Bits, __VA_ARGS__;                                 \
   } T;                                                                         \
   LLVM_PACKED_END                                                              \
   static_assert(sizeof(T##Bitfield) <= 8, "Bitfield overflow")
 
 /// Define an empty bitfield for type 'T'.
 #define SWIFT_INLINE_BITFIELD_EMPTY(T, U) \
-  enum { Num##T##Bits = Num##U##Bits }
+  enum { NumberOf##T##Bits = NumberOf##U##Bits }
 
 // XXX/HACK: templated max() doesn't seem to work in a bitfield size context.
 constexpr unsigned bitmax(unsigned a, unsigned b) {
diff --git a/include/swift/Basic/LLVMInitialize.h b/include/swift/Basic/LLVMInitialize.h
index 930a44d3cb450..a27f698e8259b 100644
--- a/include/swift/Basic/LLVMInitialize.h
+++ b/include/swift/Basic/LLVMInitialize.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -19,14 +19,16 @@
 #ifndef SWIFT_BASIC_LLVMINITIALIZE_H
 #define SWIFT_BASIC_LLVMINITIALIZE_H
 
+#include "swift/Basic/Compiler.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/TargetSelect.h"
 
-#define PROGRAM_START(argc, argv) \
-  llvm::InitLLVM _INITIALIZE_LLVM(argc, argv)
+#define PROGRAM_START(argc, argv)                                              \
+  llvm::InitLLVM _INITIALIZE_LLVM(argc, argv);                                 \
+  llvm::setBugReportMsg(SWIFT_CRASH_BUG_REPORT_MESSAGE "\n")
 
 #define INITIALIZE_LLVM() \
   do { \
diff --git a/include/swift/Basic/LangOptions.h b/include/swift/Basic/LangOptions.h
index 01e0162a9a546..4687beea7d70d 100644
--- a/include/swift/Basic/LangOptions.h
+++ b/include/swift/Basic/LangOptions.h
@@ -22,6 +22,7 @@
 #include "swift/Basic/Feature.h"
 #include "swift/Basic/FunctionBodySkipping.h"
 #include "swift/Basic/LLVM.h"
+#include "swift/Basic/Platform.h"
 #include "swift/Basic/PlaygroundOption.h"
 #include "swift/Basic/Version.h"
 #include "swift/Config.h"
@@ -45,6 +46,7 @@ namespace swift {
 
   struct DiagnosticBehavior;
   class DiagnosticEngine;
+  class FrontendOptions;
 
   /// Kind of implicit platform conditions.
   enum class PlatformConditionKind {
@@ -66,22 +68,24 @@ namespace swift {
     Complete,
   };
 
-  /// Access or distribution level of a library.
+  /// Intended distribution level of a module.
+  ///
+  /// Ordered from more private to more public.
   enum class LibraryLevel : uint8_t {
-    /// Application Programming Interface that is publicly distributed so
-    /// public decls are really public and only @_spi decls are SPI.
-    API,
+    /// This isn't a library or the library distribution intent is unknown.
+    Other,
 
-    /// System Programming Interface that has restricted distribution
-    /// all decls in the module are considered to be SPI including public ones.
-    SPI,
-
-    /// Internal Programming Interface that is not distributed and only usable
-    /// from within a project.
+    /// Internal Programming Interface: the module is not distributed and
+    /// only usable from within its project.
     IPI,
 
-    /// The library has some other undefined distribution.
-    Other
+    /// System Programming Interface: the module has restricted distribution,
+    /// all public decls in the module are considered to be SPI.
+    SPI,
+
+    /// Application Programming Interface: the module is distributed publicly,
+    /// public decls are really public and only @_spi decls are SPI.
+    API,
   };
 
   enum class AccessNoteDiagnosticBehavior : uint8_t {
@@ -184,6 +188,9 @@ namespace swift {
     /// Swift runtime version to compile for.
     version::Version RuntimeVersion = version::Version::getCurrentLanguageVersion();
 
+    /// The minimum Swift runtime version that the progam can be deployed to.
+    version::Version MinSwiftRuntimeVersion;
+
     /// PackageDescription version to compile for.
     version::Version PackageDescriptionVersion;
 
@@ -269,9 +276,6 @@ namespace swift {
     /// Emit a remark on early exit in explicit interface build
     bool EnableSkipExplicitInterfaceModuleBuildRemarks = false;
 
-    /// Emit a remark when \c \@abi infers an attribute or modifier.
-    bool EnableABIInferenceRemarks = false;
-
     ///
     /// Support for alternate usage modes
     ///
@@ -323,6 +327,8 @@ namespace swift {
     /// Flags for use by tests
     ///
 
+    bool UseStaticStandardLibrary = false;
+
     /// Enable Objective-C Runtime interop code generation and build
     /// configuration options.
     bool EnableObjCInterop = true;
@@ -342,7 +348,8 @@ namespace swift {
     std::optional<version::Version> FormalCxxInteropMode;
 
     void setCxxInteropFromArgs(llvm::opt::ArgList &Args,
-                               swift::DiagnosticEngine &Diags);
+                               swift::DiagnosticEngine &Diags,
+                               const FrontendOptions &FrontendOpts);
 
     /// The C++ standard library used for the current build. This can differ
     /// from the default C++ stdlib on a particular platform when `-Xcc
@@ -354,8 +361,6 @@ namespace swift {
       return CXXStdlib == PlatformDefaultCXXStdlib;
     }
 
-    bool CForeignReferenceTypes = false;
-
     /// Imports getters and setters as computed properties.
     bool CxxInteropGettersSettersAsProperties = false;
 
@@ -409,10 +414,6 @@ namespace swift {
     /// Specifies how strict concurrency checking will be.
     StrictConcurrency StrictConcurrencyLevel = StrictConcurrency::Minimal;
 
-    /// Specifies the name of the executor factory to use to create the
-    /// default executors for Swift Concurrency.
-    std::optional<std::string> ExecutorFactory;
-
     /// Enable experimental concurrency model.
     bool EnableExperimentalConcurrency = false;
 
@@ -497,6 +498,9 @@ namespace swift {
     std::shared_ptr<llvm::Regex> OptimizationRemarkPassedPattern;
     std::shared_ptr<llvm::Regex> OptimizationRemarkMissedPattern;
 
+    /// The path to load access notes from.
+    std::string AccessNotesPath;
+
     /// How should we emit diagnostics about access notes?
     AccessNoteDiagnosticBehavior AccessNoteBehavior =
         AccessNoteDiagnosticBehavior::RemarkOnFailureOrSuccess;
@@ -583,10 +587,18 @@ namespace swift {
     /// algorithm.
     unsigned RequirementMachineMaxRuleLength = 12;
 
-    /// Maximum concrete type nesting depth for requirement machine property map
-    /// algorithm.
+    /// Maximum concrete type nesting depth (when type is viewed as a tree) for
+    /// requirement machine property map algorithm.
     unsigned RequirementMachineMaxConcreteNesting = 30;
 
+    /// Maximum concrete type size (total number of nodes in the type tree) for
+    /// requirement machine property map algorithm.
+    unsigned RequirementMachineMaxConcreteSize = 4000;
+
+    /// Maximum number of "type difference" structures for the requirement machine
+    /// property map algorithm.
+    unsigned RequirementMachineMaxTypeDifferences = 13000;
+
     /// Maximum number of attempts to make when splitting concrete equivalence
     /// classes.
     unsigned RequirementMachineMaxSplitConcreteEquivClassAttempts = 2;
@@ -609,6 +621,14 @@ namespace swift {
     /// rewrite system.
     bool EnableRequirementMachineOpaqueArchetypes = false;
 
+    /// Maximum nesting depth for type substitution operations, to prevent
+    /// runaway recursion.
+    unsigned MaxSubstitutionDepth = 500;
+
+    /// Maximum step count for type substitution operations, to prevent
+    /// runaway recursion.
+    unsigned MaxSubstitutionCount = 120000;
+
     /// Enable implicit lifetime dependence for ~Escapable return types.
     bool EnableExperimentalLifetimeDependenceInference = false;
 
@@ -631,12 +651,19 @@ namespace swift {
     /// Enables dumping macro expansions.
     bool DumpMacroExpansions = false;
 
+    /// Enables dumping imports for each SourceFile.
+    bool DumpSourceFileImports = false;
+
     /// The model of concurrency to be used.
     ConcurrencyModel ActiveConcurrencyModel = ConcurrencyModel::Standard;
 
     /// All block list configuration files to be honored in this compilation.
     std::vector<std::string> BlocklistConfigFilePaths;
 
+    /// List of top level modules to be considered as if they had require ObjC
+    /// in their module map.
+    llvm::SmallVector<StringRef> ModulesRequiringObjC;
+
     /// Whether to ignore checks that a module is resilient during
     /// type-checking, SIL verification, and IR emission,
     bool BypassResilienceChecks = false;
@@ -678,18 +705,7 @@ namespace swift {
     /// This is only implemented on certain OSs. If no target has been
     /// configured, returns v0.0.0.
     llvm::VersionTuple getMinPlatformVersion() const {
-      if (Target.isMacOSX()) {
-        llvm::VersionTuple OSVersion;
-        Target.getMacOSXVersion(OSVersion);
-        return OSVersion;
-      } else if (Target.isiOS()) {
-        return Target.getiOSVersion();
-      } else if (Target.isWatchOS()) {
-        return Target.getOSVersion();
-      } else if (Target.isXROS()) {
-        return Target.getOSVersion();
-      }
-      return llvm::VersionTuple(/*Major=*/0, /*Minor=*/0, /*Subminor=*/0);
+      return getVersionForTriple(Target);
     }
 
     /// Sets an implicit platform condition.
@@ -837,7 +853,7 @@ namespace swift {
 
     /// A wrapper around the feature state enumeration.
     struct FeatureState {
-      enum class Kind : uint8_t { Off, EnabledForAdoption, Enabled };
+      enum class Kind : uint8_t { Off, EnabledForMigration, Enabled };
 
     private:
       Feature feature;
@@ -850,9 +866,9 @@ namespace swift {
       /// Returns whether the feature is enabled.
       bool isEnabled() const;
 
-      /// Returns whether the feature is enabled in adoption mode. Should only
+      /// Returns whether the feature is enabled in migration mode. Should only
       /// be called if the feature is known to support this mode.
-      bool isEnabledForAdoption() const;
+      bool isEnabledForMigration() const;
 
       operator Kind() const { return state; }
     };
@@ -879,15 +895,21 @@ namespace swift {
     FeatureState getFeatureState(Feature feature) const;
 
     /// Returns whether the given feature is enabled.
-    bool hasFeature(Feature feature) const;
+    ///
+    /// If allowMigration is set, also returns true when the feature has been
+    /// enabled for migration.
+    bool hasFeature(Feature feature, bool allowMigration = false) const;
 
     /// Returns whether a feature with the given name is enabled. Returns
     /// `false` if a feature by this name is not known.
     bool hasFeature(llvm::StringRef featureName) const;
 
-    /// Enables the given feature (enables in adoption mode if `forAdoption` is
-    /// `true`).
-    void enableFeature(Feature feature, bool forAdoption = false);
+    /// Returns whether the given feature is enabled for migration.
+    bool isMigratingToFeature(Feature feature) const;
+
+    /// Enables the given feature (enables in migration mode if `forMigration`
+    /// is `true`).
+    void enableFeature(Feature feature, bool forMigration = false);
 
     /// Disables the given feature.
     void disableFeature(Feature feature);
@@ -931,6 +953,10 @@ namespace swift {
     /// (It's arbitrary, but will keep the compiler from taking too much time.)
     unsigned SwitchCheckingInvocationThreshold = 200000;
 
+    /// The maximum number of `@dynamicMemberLookup`s that can be chained to
+    /// resolve a member reference.
+    unsigned DynamicMemberLookupDepthLimit = 100;
+
     /// If true, the time it takes to type-check each function will be dumped
     /// to llvm::errs().
     bool DebugTimeFunctionBodies = false;
@@ -972,14 +998,11 @@ namespace swift {
     /// is for testing purposes.
     std::vector<std::string> DebugForbidTypecheckPrefixes;
 
-    /// Disable the shrink phase of the expression type checker.
-    bool SolverDisableShrink = false;
-
     /// Enable experimental operator designated types feature.
     bool EnableOperatorDesignatedTypes = false;
 
-    /// Disable constraint system performance hacks.
-    bool DisableConstraintSolverPerformanceHacks = false;
+    /// Enable old constraint system performance hacks.
+    bool EnableConstraintSolverPerformanceHacks = false;
 
     /// See \ref FrontendOptions.PrintFullConvention
     bool PrintFullConvention = false;
@@ -993,6 +1016,9 @@ namespace swift {
 
     /// Disable the component splitter phase of the expression type checker.
     bool SolverDisableSplitter = false;
+
+    /// Enable the experimental "prepared overloads" optimization.
+    bool SolverEnablePreparedOverloads = false;
   };
 
   /// Options for controlling the behavior of the Clang importer.
@@ -1028,6 +1054,10 @@ namespace swift {
     /// The bridging header PCH file.
     std::string BridgingHeaderPCH;
 
+    /// Whether the bridging header and PCH file are considered to be
+    /// internal imports.
+    bool BridgingHeaderIsInternal = false;
+
     /// When automatically generating a precompiled header from the bridging
     /// header, place it in this directory.
     std::string PrecompiledHeaderOutputDir;
@@ -1088,6 +1118,10 @@ namespace swift {
     /// When set, don't enforce warnings with -Werror.
     bool DebuggerSupport = false;
 
+    /// Prefer the serialized preprocessed header over the one on disk.
+    /// Used by LLDB.
+    bool PreferSerializedBridgingHeader = false;
+
     /// When set, ClangImporter is disabled, and all requests go to the
     /// DWARFImporter delegate.
     bool DisableSourceImport = false;
@@ -1101,16 +1135,19 @@ namespace swift {
     /// built and provided to the compiler invocation.
     bool DisableImplicitClangModules = false;
 
-    /// Enable ClangIncludeTree for explicit module builds scanning.
-    bool UseClangIncludeTree = false;
-
-    /// Using ClangIncludeTreeRoot for compilation.
-    bool HasClangIncludeTreeRoot = false;
-
     /// Whether the dependency scanner should construct all swift-frontend
     /// invocations directly from clang cc1 args.
     bool ClangImporterDirectCC1Scan = false;
 
+    /// Whether we should import values (initializer expressions) of constant
+    /// globals.
+    bool EnableConstValueImporting = true;
+
+    /// Whether the importer should expect all APINotes to be wrapped
+    /// in versioned attributes, where the importer must select the appropriate
+    /// ones to apply.
+    bool LoadVersionIndependentAPINotes = false;
+
     /// Return a hash code of any components from these options that should
     /// contribute to a Swift Bridging PCH hash.
     llvm::hash_code getPCHHashComponents() const {
diff --git a/include/swift/Basic/Located.h b/include/swift/Basic/Located.h
index f9f5b2296456f..e0db2f0385f89 100644
--- a/include/swift/Basic/Located.h
+++ b/include/swift/Basic/Located.h
@@ -71,7 +71,7 @@ struct DenseMapInfo<swift::Located<T>> {
   }
 
   static unsigned getHashValue(const swift::Located<T> &LocatedVal) {
-    return combineHashValue(DenseMapInfo<T>::getHashValue(LocatedVal.Item),
+    return detail::combineHashValue(DenseMapInfo<T>::getHashValue(LocatedVal.Item),
                             DenseMapInfo<swift::SourceLoc>::getHashValue(LocatedVal.Loc));
   }
 
@@ -82,4 +82,12 @@ struct DenseMapInfo<swift::Located<T>> {
 };
 } // namespace llvm
 
+namespace swift {
+  template<typename T>
+  llvm::hash_code hash_value(const Located<T> &LocatedVal) {
+    return llvm::DenseMapInfo<Located<T>>::getHashValue(LocatedVal);
+  }
+} // namespace swift
+
+
 #endif // SWIFT_BASIC_LOCATED_H
diff --git a/include/swift/Basic/OwnedString.h b/include/swift/Basic/OwnedString.h
index 109eb003e6819..c37370d18c052 100644
--- a/include/swift/Basic/OwnedString.h
+++ b/include/swift/Basic/OwnedString.h
@@ -35,8 +35,7 @@ class OwnedString {
   class TextOwner final : public llvm::ThreadSafeRefCountedBase<TextOwner>,
                           public llvm::TrailingObjects<TextOwner, char> {
     TextOwner(StringRef Text) {
-      std::uninitialized_copy(Text.begin(), Text.end(),
-                              getTrailingObjects<char>());
+      std::uninitialized_copy(Text.begin(), Text.end(), getTrailingObjects());
     }
 
   public:
@@ -50,7 +49,7 @@ class OwnedString {
     /// data.
     void operator delete(void *p) { ::operator delete(p); }
 
-    const char *getText() const { return getTrailingObjects<char>(); }
+    const char *getText() const { return getTrailingObjects(); }
   };
 
   /// The text this owned string represents
diff --git a/include/swift/Basic/Platform.h b/include/swift/Basic/Platform.h
index 94515f6dbd890..bf40edad76b33 100644
--- a/include/swift/Basic/Platform.h
+++ b/include/swift/Basic/Platform.h
@@ -85,6 +85,9 @@ namespace swift {
   /// returned.
   StringRef getPlatformNameForTriple(const llvm::Triple &triple);
 
+  /// Returns the version tuple for a given target triple
+  llvm::VersionTuple getVersionForTriple(const llvm::Triple &triple);
+
   /// Returns the platform Kind for Darwin triples.
   DarwinPlatformKind getDarwinPlatformKind(const llvm::Triple &triple);
 
@@ -123,6 +126,16 @@ namespace swift {
   llvm::VersionTuple getTargetSDKVersion(clang::DarwinSDKInfo &SDKInfo,
                                          const llvm::Triple &triple);
 
+  /// Compute a target triple that is canonicalized using the passed triple.
+  /// \returns nullopt if computation fails.
+  std::optional<llvm::Triple> getCanonicalTriple(const llvm::Triple &triple);
+
+  /// Compare triples for equality but also including OSVersion.
+  inline bool areTriplesStrictlyEqual(const llvm::Triple &lhs,
+                                      const llvm::Triple &rhs) {
+    return (lhs == rhs) && (lhs.getOSVersion() == rhs.getOSVersion());
+  }
+
   /// Get SDK build version.
   std::string getSDKBuildVersion(StringRef SDKPath);
   std::string getSDKBuildVersionFromPlist(StringRef Path);
diff --git a/include/swift/Basic/PossiblyUniquePtr.h b/include/swift/Basic/PossiblyUniquePtr.h
new file mode 100644
index 0000000000000..04f4ff3e7ede3
--- /dev/null
+++ b/include/swift/Basic/PossiblyUniquePtr.h
@@ -0,0 +1,173 @@
+//===--- PossiblyUniquePtr.h - A dynamic smart pointer ----------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+///  \file
+///
+///  This file defines PossiblyUniquePtr, a smart pointer template that
+///  typically owns its pointee but can dynamically just contain an unowned
+///  pointer.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_BASIC_POSSIBLY_UNIQUE_PTR_H
+#define SWIFT_BASIC_POSSIBLY_UNIQUE_PTR_H
+
+#include "llvm/ADT/PointerIntPair.h"
+#include "swift/Basic/Compiler.h"
+
+namespace swift {
+
+enum PointerIsOwned_t: bool {
+  PointerIsNotOwned = false,
+  PointerIsOwned = true
+};
+
+/// Essentially std::unique_ptr except it dynamically tracks whether the
+/// pointer is actually owned.
+///
+/// The operations which possibly transfer ownership into a PossiblyUniquePtr
+/// (the constructor and `reset`) privilege the owning case. This allows
+/// PossiblyUniquePtr<T> to serve as a drop-in replacement for
+/// std::unique_ptr<T>.
+template <class T, class PtrTraits = llvm::PointerLikeTypeTraits<T*>>
+class SWIFT_TRIVIAL_ABI PossiblyUniquePtr {
+  llvm::PointerIntPair<T*, 1, bool, PtrTraits> Value;
+
+  // Befriend all other specializations of this class, for the use of the
+  // converting constructor and assignment operator.
+  template <class, class>
+  friend class PossiblyUniquePtr;
+
+public:
+  PossiblyUniquePtr() {}
+
+  // Allow implicit conversion from a null pointer.
+  PossiblyUniquePtr(std::nullptr_t) {}
+
+  // Require conversion from any other pointer to be explicit.
+  explicit PossiblyUniquePtr(T *pointer,
+                             PointerIsOwned_t owned = PointerIsOwned)
+      : Value(pointer, owned) {
+    assert((pointer != nullptr || !owned) && "claiming ownership of null pointer");
+  }
+
+  PossiblyUniquePtr(PossiblyUniquePtr &&other)
+      : Value(other.Value) {
+    other.dropValue();
+  }
+
+  PossiblyUniquePtr &operator=(PossiblyUniquePtr &&other) {
+    destroyValue();
+    Value = other.Value;
+    other.dropValue();
+    return *this;
+  }
+
+  ~PossiblyUniquePtr() {
+    destroyValue();
+  }
+
+  // Converting constructor.
+  template <class U, class UTraits>
+  PossiblyUniquePtr(PossiblyUniquePtr<U,UTraits> &&other)
+      : Value(other.Value.getPointer(), other.Value.getInt()) {
+    other.dropValue();
+  }
+
+  // Converting assignment operator.
+  template <class U, class UTraits>
+  PossiblyUniquePtr &operator=(PossiblyUniquePtr<U,UTraits> &&other) {
+    destroyValue();
+    Value.setPointerAndInt(other.Value.getPointer(),
+                           other.Value.getInt());
+    other.dropValue();
+    return *this;
+  }
+
+  template <class ObjectType, class... Args>
+  static PossiblyUniquePtr make(Args &&...args) {
+    return PossiblyUniquePtr(new ObjectType(std::forward<Args>(args)...));
+  }
+
+  /// As a unique pointer, PossiblyUniquePtr is non-copyable.
+  PossiblyUniquePtr(const PossiblyUniquePtr &other) = delete;
+  PossiblyUniquePtr &operator=(const PossiblyUniquePtr &other) = delete;
+
+  explicit operator bool() const {
+    return Value.getPointer() != nullptr;
+  }
+
+  T &operator*() const {
+    return *get_nonnull();
+  }
+  T *operator->() const {
+    return get_nonnull();
+  }
+
+  /// Reset the value of this object to the given pointer.
+  ///
+  /// Destroys the current value, if any.
+  void reset(T *pointer = nullptr, PointerIsOwned_t owned = PointerIsOwned) & {
+    destroyValue();
+    Value.setPointerAndInt(pointer, owned);
+  }
+
+  /// Borrow the current pointer value, leaving ownership (if any) with this object.
+  T *get() const {
+    return Value.getPointer();
+  }
+
+  /// Borrow the current pointer value, leaving ownership (if any) with this object.
+  /// Asserts that the pointer is non-null.
+  T *get_nonnull() const {
+    auto value = get();
+    assert(value);
+    return value;
+  }
+
+  /// Determines whether this object owns its pointer value.
+  PointerIsOwned_t isOwned() const {
+    return PointerIsOwned_t(Value.getInt());
+  }
+
+  /// Release ownership of the pointer, making the caller responsible for it.
+  /// This can only be called on an owned pointer.
+  T *releaseOwned() {
+    assert(isOwned());
+    auto value = get();
+    dropValue();
+    return value;
+  }
+
+private:
+  /// Destroy the value, if we own it.
+  void destroyValue() {
+    if (Value.getInt()) {
+      delete Value.getPointer();
+    }
+  }
+
+  /// Clear the stored value without asserting ownership.
+  void dropValue() & {
+    Value.setPointerAndInt(nullptr, 0);
+  }
+};
+
+template <class ObjectType, class... As>
+PossiblyUniquePtr<ObjectType> make_possibly_unique(As &&...args) {
+  return PossiblyUniquePtr<ObjectType>::
+      template make<ObjectType>(std::forward<As>(args)...);
+}
+
+} // end namespace swift
+
+#endif
diff --git a/include/swift/Basic/RelativePointer.h b/include/swift/Basic/RelativePointer.h
index a42801d0d7400..4d53652a949e7 100644
--- a/include/swift/Basic/RelativePointer.h
+++ b/include/swift/Basic/RelativePointer.h
@@ -132,7 +132,10 @@
 #ifndef SWIFT_BASIC_RELATIVEPOINTER_H
 #define SWIFT_BASIC_RELATIVEPOINTER_H
 
+#include <cassert>
 #include <cstdint>
+#include <type_traits>
+#include <utility>
 
 namespace swift {
 
diff --git a/include/swift/Basic/SimpleDisplay.h b/include/swift/Basic/SimpleDisplay.h
index 349da1db5f661..742de8f8af583 100644
--- a/include/swift/Basic/SimpleDisplay.h
+++ b/include/swift/Basic/SimpleDisplay.h
@@ -19,6 +19,7 @@
 #ifndef SWIFT_BASIC_SIMPLE_DISPLAY_H
 #define SWIFT_BASIC_SIMPLE_DISPLAY_H
 
+#include "swift/Basic/LLVM.h"
 #include "llvm/ADT/TinyPtrVector.h"
 #include "llvm/Support/raw_ostream.h"
 #include <tuple>
@@ -167,7 +168,7 @@ namespace swift {
     if (const auto t = ptrUnion.template dyn_cast<T>())
       simple_display(out, t);
     else
-      simple_display(out, ptrUnion.template get<U>());
+      simple_display(out, cast<U>(ptrUnion));
   }
 }
 
diff --git a/include/swift/Basic/SourceLoc.h b/include/swift/Basic/SourceLoc.h
index 355e55763506d..c362c8e1ca229 100644
--- a/include/swift/Basic/SourceLoc.h
+++ b/include/swift/Basic/SourceLoc.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -17,59 +17,98 @@
 #ifndef SWIFT_BASIC_SOURCELOC_H
 #define SWIFT_BASIC_SOURCELOC_H
 
+/// `SourceLoc.h` is imported into Swift. Be *very* careful with what you
+/// include here and keep these includes minimal!
+/// If you don't need to import a header into Swift, include it in the `#ifdef`
+/// block below instead.
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
+#include "swift/Basic/SwiftBridging.h"
+#include <assert.h>
+#include <stdint.h>
+
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
 #include "swift/Basic/Debug.h"
 #include "swift/Basic/LLVM.h"
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/SMLoc.h"
-#include <assert.h>
 #include <functional>
 
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
+SWIFT_BEGIN_NULLABILITY_ANNOTATIONS
+
 namespace swift {
-  class SourceManager;
+class SourceManager;
 
-/// SourceLoc in swift is just an SMLoc.  We define it as a different type
-/// (instead of as a typedef) just to remove the "getFromPointer" methods and
-/// enforce purity in the Swift codebase.
+/// `SourceLoc` just wraps a `const char *`.  We define it as a different type
+/// (instead of as a typedef) from `llvm::SMLoc` to enforce purity in the
+/// Swift codebase.
 class SourceLoc {
   friend class SourceManager;
   friend class SourceRange;
   friend class CharSourceRange;
   friend class DiagnosticConsumer;
 
-  llvm::SMLoc Value;
+  const char *_Nullable Pointer = nullptr;
 
 public:
   SourceLoc() {}
-  explicit SourceLoc(llvm::SMLoc Value) : Value(Value) {}
-  
-  bool isValid() const { return Value.isValid(); }
-  bool isInvalid() const { return !isValid(); }
+#ifdef COMPILED_WITH_SWIFT
+  SWIFT_NAME("init(raw:)")
+  SourceLoc(const void *_Nullable Pointer) : Pointer((const char *)Pointer) {}
+#endif
+
+  SWIFT_UNAVAILABLE("Use 'init(raw:)' instead")
+  static SourceLoc getFromPointer(const char *_Nullable Pointer) {
+    SourceLoc Loc;
+    Loc.Pointer = Pointer;
+    return Loc;
+  }
 
-  /// An explicit bool operator so one can check if a SourceLoc is valid in an
-  /// if statement:
-  ///
-  /// if (auto x = getSourceLoc()) { ... }
-  explicit operator bool() const { return isValid(); }
+  SWIFT_UNAVAILABLE("Use 'raw' instead")
+  const char *_Nullable getPointer() const { return Pointer; }
+  SWIFT_UNAVAILABLE("Use 'raw' instead")
+  const void *_Nullable getOpaquePointerValue() const { return Pointer; }
+#ifdef COMPILED_WITH_SWIFT
+  SWIFT_COMPUTED_PROPERTY
+  const void *_Nullable getRaw() const { return getOpaquePointerValue(); }
+#endif
+
+  bool isValid() const { return Pointer != nullptr; }
+  bool isInvalid() const { return !isValid(); }
 
-  bool operator==(const SourceLoc &RHS) const { return RHS.Value == Value; }
-  bool operator!=(const SourceLoc &RHS) const { return !operator==(RHS); }
-  
   /// Return a source location advanced a specified number of bytes.
+  SWIFT_NAME("advanced(by:)")
   SourceLoc getAdvancedLoc(int ByteOffset) const {
     assert(isValid() && "Can't advance an invalid location");
-    return SourceLoc(
-        llvm::SMLoc::getFromPointer(Value.getPointer() + ByteOffset));
+    return SourceLoc::getFromPointer(Pointer + ByteOffset);
   }
 
+  SWIFT_UNAVAILABLE("Unavailable in Swift")
   SourceLoc getAdvancedLocOrInvalid(int ByteOffset) const {
     if (isValid())
       return getAdvancedLoc(ByteOffset);
     return SourceLoc();
   }
 
-  const void *getOpaquePointerValue() const { return Value.getPointer(); }
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
+  /// An explicit bool operator so one can check if a SourceLoc is valid in an
+  /// if statement:
+  ///
+  /// if (auto x = getSourceLoc()) { ... }
+  explicit operator bool() const { return isValid(); }
+
+  operator llvm::SMLoc() const { return llvm::SMLoc::getFromPointer(Pointer); }
+
+  bool operator==(const SourceLoc &RHS) const { return RHS.Pointer == Pointer; }
+  bool operator!=(const SourceLoc &RHS) const { return !operator==(RHS); }
 
   /// Print out the SourceLoc.  If this location is in the same buffer
   /// as specified by \c LastBufferID, then we don't print the filename.  If
@@ -88,13 +127,15 @@ class SourceLoc {
 
   SWIFT_DEBUG_DUMPER(dump(const SourceManager &SM));
 
-	friend size_t hash_value(SourceLoc loc) {
-		return reinterpret_cast<uintptr_t>(loc.getOpaquePointerValue());
-	}
+  friend size_t hash_value(SourceLoc loc) {
+    return reinterpret_cast<uintptr_t>(loc.getOpaquePointerValue());
+  }
+
+  friend void simple_display(raw_ostream &OS, const SourceLoc &loc) {
+    // Nothing meaningful to print.
+  }
 
-	friend void simple_display(raw_ostream &OS, const SourceLoc &loc) {
-		// Nothing meaningful to print.
-	}
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 };
 
 /// SourceRange in swift is a pair of locations.  However, note that the end
@@ -103,10 +144,18 @@ class SourceLoc {
 /// sure that proper conversions happen where important.
 class SourceRange {
 public:
-  SourceLoc Start, End;
+  SWIFT_NAME("start")
+  SourceLoc Start;
+
+  SWIFT_NAME("end")
+  SourceLoc End;
 
   SourceRange() {}
+
+  SWIFT_NAME("init(start:)")
   SourceRange(SourceLoc Loc) : Start(Loc), End(Loc) {}
+
+  SWIFT_NAME("init(start:end:)")
   SourceRange(SourceLoc Start, SourceLoc End) : Start(Start), End(End) {
     assert(Start.isValid() == End.isValid() &&
            "Start and end should either both be valid or both be invalid!");
@@ -115,6 +164,9 @@ class SourceRange {
   bool isValid() const { return Start.isValid(); }
   bool isInvalid() const { return !isValid(); }
 
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
   /// An explicit bool operator so one can check if a SourceRange is valid in an
   /// if statement:
   ///
@@ -172,6 +224,7 @@ class SourceRange {
     // Nothing meaningful to print.
   }
 
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 };
 
 /// A half-open character-based source range.
@@ -183,9 +236,13 @@ class CharSourceRange {
   /// Constructs an invalid range.
   CharSourceRange() = default;
 
+  SWIFT_NAME("init(start:byteLength:)")
   CharSourceRange(SourceLoc Start, unsigned ByteLength)
     : Start(Start), ByteLength(ByteLength) {}
 
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
   /// Constructs a character range which starts and ends at the
   /// specified character locations.
   CharSourceRange(const SourceManager &SM, SourceLoc Start, SourceLoc End);
@@ -193,44 +250,51 @@ class CharSourceRange {
   /// Use Lexer::getCharSourceRangeFromSourceRange() instead.
   CharSourceRange(const SourceManager &SM, SourceRange Range) = delete;
 
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
   bool isValid() const { return Start.isValid(); }
   bool isInvalid() const { return !isValid(); }
 
-  bool operator==(const CharSourceRange &other) const {
-    return Start == other.Start && ByteLength == other.ByteLength;
-  }
-  bool operator!=(const CharSourceRange &other) const {
-    return !operator==(other);
-  }
-
+  SWIFT_COMPUTED_PROPERTY
   SourceLoc getStart() const { return Start; }
+  SWIFT_COMPUTED_PROPERTY
   SourceLoc getEnd() const { return Start.getAdvancedLocOrInvalid(ByteLength); }
 
+  /// Return the length of this valid range in bytes.  Can be zero.
+  SWIFT_COMPUTED_PROPERTY
+  unsigned getByteLength() const {
+    assert(isValid() && "length does not make sense for an invalid range");
+    return ByteLength;
+  }
+
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
   /// Returns true if the given source location is contained in the range.
   bool contains(SourceLoc loc) const {
     auto less = std::less<const char *>();
     auto less_equal = std::less_equal<const char *>();
-    return less_equal(getStart().Value.getPointer(), loc.Value.getPointer()) &&
-           less(loc.Value.getPointer(), getEnd().Value.getPointer());
+    return less_equal(getStart().Pointer, loc.Pointer) &&
+           less(loc.Pointer, getEnd().Pointer);
   }
 
   bool contains(CharSourceRange Other) const {
     auto less_equal = std::less_equal<const char *>();
     return contains(Other.getStart()) &&
-     less_equal(Other.getEnd().Value.getPointer(), getEnd().Value.getPointer());
+           less_equal(Other.getEnd().Pointer, getEnd().Pointer);
   }
 
   /// expands *this to cover Other
   void widen(CharSourceRange Other) {
-    auto Diff = Other.getEnd().Value.getPointer() - getEnd().Value.getPointer();
+    auto Diff = Other.getEnd().Pointer - getEnd().Pointer;
     if (Diff > 0) {
       ByteLength += Diff;
     }
-    const auto MyStartPtr = getStart().Value.getPointer();
-    Diff = MyStartPtr - Other.getStart().Value.getPointer();
+    const auto MyStartPtr = getStart().Pointer;
+    Diff = MyStartPtr - Other.getStart().Pointer;
     if (Diff > 0) {
       ByteLength += Diff;
-      Start = SourceLoc(llvm::SMLoc::getFromPointer(MyStartPtr - Diff));
+      Start = SourceLoc::getFromPointer(MyStartPtr - Diff);
     }
   }
 
@@ -239,16 +303,15 @@ class CharSourceRange {
     return contains(Other.getStart()) || Other.contains(getStart());
   }
 
-  StringRef str() const {
-    return StringRef(Start.Value.getPointer(), ByteLength);
-  }
+  StringRef str() const { return StringRef(Start.Pointer, ByteLength); }
 
-  /// Return the length of this valid range in bytes.  Can be zero.
-  unsigned getByteLength() const {
-    assert(isValid() && "length does not make sense for an invalid range");
-    return ByteLength;
+  bool operator==(const CharSourceRange &other) const {
+    return Start == other.Start && ByteLength == other.ByteLength;
   }
-  
+  bool operator!=(const CharSourceRange &other) const {
+    return !operator==(other);
+  }
+
   /// Print out the CharSourceRange.  If the locations are in the same buffer
   /// as specified by LastBufferID, then we don't print the filename.  If not,
   /// we do print the filename, and then update LastBufferID with the BufferID
@@ -261,26 +324,31 @@ class CharSourceRange {
     unsigned Tmp = ~0U;
     print(OS, SM, Tmp, PrintText);
   }
-  
+
   SWIFT_DEBUG_DUMPER(dump(const SourceManager &SM));
+
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 };
 
 } // end namespace swift
 
+// Not imported into Swift in pure bridging mode.
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
 namespace llvm {
 template <typename T, typename Enable> struct DenseMapInfo;
 
 template <> struct DenseMapInfo<swift::SourceLoc> {
   static swift::SourceLoc getEmptyKey() {
-    return swift::SourceLoc(
-        SMLoc::getFromPointer(DenseMapInfo<const char *>::getEmptyKey()));
+    return swift::SourceLoc::getFromPointer(
+        DenseMapInfo<const char *>::getEmptyKey());
   }
 
   static swift::SourceLoc getTombstoneKey() {
     // Make this different from empty key. See for context:
     // http://lists.llvm.org/pipermail/llvm-dev/2015-July/088744.html
-    return swift::SourceLoc(
-        SMLoc::getFromPointer(DenseMapInfo<const char *>::getTombstoneKey()));
+    return swift::SourceLoc::getFromPointer(
+        DenseMapInfo<const char *>::getTombstoneKey());
   }
 
   static unsigned getHashValue(const swift::SourceLoc &Val) {
@@ -296,15 +364,15 @@ template <> struct DenseMapInfo<swift::SourceLoc> {
 
 template <> struct DenseMapInfo<swift::SourceRange> {
   static swift::SourceRange getEmptyKey() {
-    return swift::SourceRange(swift::SourceLoc(
-        SMLoc::getFromPointer(DenseMapInfo<const char *>::getEmptyKey())));
+    return swift::SourceRange(swift::SourceLoc::getFromPointer(
+        DenseMapInfo<const char *>::getEmptyKey()));
   }
 
   static swift::SourceRange getTombstoneKey() {
     // Make this different from empty key. See for context:
     // http://lists.llvm.org/pipermail/llvm-dev/2015-July/088744.html
-    return swift::SourceRange(swift::SourceLoc(
-        SMLoc::getFromPointer(DenseMapInfo<const char *>::getTombstoneKey())));
+    return swift::SourceRange(swift::SourceLoc::getFromPointer(
+        DenseMapInfo<const char *>::getTombstoneKey()));
   }
 
   static unsigned getHashValue(const swift::SourceRange &Val) {
@@ -319,4 +387,8 @@ template <> struct DenseMapInfo<swift::SourceRange> {
 };
 } // namespace llvm
 
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+
+SWIFT_END_NULLABILITY_ANNOTATIONS
+
 #endif // SWIFT_BASIC_SOURCELOC_H
diff --git a/include/swift/Basic/SourceManager.h b/include/swift/Basic/SourceManager.h
index 60cbb2b093d21..3fde295946973 100644
--- a/include/swift/Basic/SourceManager.h
+++ b/include/swift/Basic/SourceManager.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -13,6 +13,7 @@
 #ifndef SWIFT_BASIC_SOURCEMANAGER_H
 #define SWIFT_BASIC_SOURCEMANAGER_H
 
+#include "swift/AST/ClangNode.h"
 #include "swift/Basic/FileSystem.h"
 #include "swift/Basic/SourceLoc.h"
 #include "clang/Basic/FileManager.h"
@@ -22,6 +23,7 @@
 #include "llvm/Support/SourceMgr.h"
 #include <map>
 #include <optional>
+#include <utility>
 #include <vector>
 
 namespace swift {
@@ -122,6 +124,10 @@ class GeneratedSourceInfo {
   /// Contains the ancestors of this source buffer, starting with the root source
   /// buffer and ending at this source buffer.
   mutable llvm::ArrayRef<unsigned> ancestors = llvm::ArrayRef<unsigned>();
+
+  /// Clang node where this buffer comes from. This should be set when this is
+  /// an 'AttributeFromClang'.
+  ClangNode clangNode = ClangNode();
 };
 
 /// This class manages and owns source buffers.
@@ -305,7 +311,7 @@ class SourceManager {
 
   /// Returns true if \c LHS is before \c RHS in the same source buffer.
   bool isBeforeInBuffer(SourceLoc LHS, SourceLoc RHS) const {
-    return LHS.Value.getPointer() < RHS.Value.getPointer();
+    return LHS.getPointer() < RHS.getPointer();
   }
 
   /// Returns true if \c range contains the location \c loc.  The location
@@ -479,7 +485,7 @@ class SourceManager {
     assert(Loc.isValid());
     int LineOffset = getLineOffset(Loc);
     int l, c;
-    std::tie(l, c) = LLVMSourceMgr.getLineAndColumn(Loc.Value, BufferID);
+    std::tie(l, c) = LLVMSourceMgr.getLineAndColumn(Loc, BufferID);
     assert(LineOffset+l > 0 && "bogus line offset");
     return { LineOffset + l, c };
   }
@@ -492,7 +498,7 @@ class SourceManager {
   std::pair<unsigned, unsigned>
   getLineAndColumnInBuffer(SourceLoc Loc, unsigned BufferID = 0) const {
     assert(Loc.isValid());
-    return LLVMSourceMgr.getLineAndColumn(Loc.Value, BufferID);
+    return LLVMSourceMgr.getLineAndColumn(Loc, BufferID);
   }
 
   /// Returns the column for the given source location in the given buffer.
diff --git a/include/swift/Basic/Statistic.h b/include/swift/Basic/Statistic.h
index 8204e826bb9b7..1e5de730f4649 100644
--- a/include/swift/Basic/Statistic.h
+++ b/include/swift/Basic/Statistic.h
@@ -411,10 +411,10 @@ template <typename T, typename U>
 FrontendStatsTracer make_tracer_pointerunion(UnifiedStatsReporter *Reporter,
                                              StringRef Name,
                                              llvm::PointerUnion<T, U> Value) {
-  if (Value.template is<T>())
-    return make_tracer_direct(Reporter, Name, Value.template get<T>());
+  if (isa<T>(Value))
+    return make_tracer_direct(Reporter, Name, cast<T>(Value));
   else
-    return make_tracer_direct(Reporter, Name, Value.template get<U>());
+    return make_tracer_direct(Reporter, Name, cast<U>(Value));
 }
 
 template <typename T>
diff --git a/include/swift/Basic/SupportedFeatures.h b/include/swift/Basic/SupportedFeatures.h
new file mode 100644
index 0000000000000..e078792b4dbc6
--- /dev/null
+++ b/include/swift/Basic/SupportedFeatures.h
@@ -0,0 +1,28 @@
+//===--- SupportedFeatures.h - Supported Features Output --------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides a high-level API for supported features info
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SUPPORTEDFEATURES_H
+#define SWIFT_SUPPORTEDFEATURES_H
+
+#include "swift/Basic/LLVM.h"
+
+namespace swift {
+namespace features {
+void printSupportedFeatures(llvm::raw_ostream &out);
+} // namespace features
+} // namespace swift
+
+#endif
diff --git a/include/swift/Basic/SwiftBridging.h b/include/swift/Basic/SwiftBridging.h
new file mode 100644
index 0000000000000..6cf10c8d90c0b
--- /dev/null
+++ b/include/swift/Basic/SwiftBridging.h
@@ -0,0 +1,124 @@
+//===--- Basic/SwiftBridging.h ----------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// This is a wrapper around `<swift/bridging>` that redefines `SWIFT_NAME` to
+/// accept a string literal, and some other helpful macros, including fallbacks
+/// for when `<swift/bridging>` is unavailable (e.g. during bootstrapping).
+///
+/// String literals enable us to properly format the long Swift declaration
+/// names specified via `SWIFT_NAME` that many of our bridging functions have.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_BASIC_SWIFT_BRIDGING_H
+#define SWIFT_BASIC_SWIFT_BRIDGING_H
+
+#include "swift/Basic/Compiler.h"
+#include "swift/Basic/Nullability.h"
+#if __has_include(<swift/bridging>)
+#include <swift/bridging>
+#else
+
+#if __has_attribute(swift_attr)
+
+/// Specifies that a C++ `class` or `struct` owns and controls the lifetime of
+/// all of the objects it references. Such type should not reference any
+/// objects whose lifetime is controlled externally. This annotation allows
+/// Swift to import methods that return a `class` or `struct` type that is
+/// annotated with this macro.
+#define SWIFT_SELF_CONTAINED __attribute__((swift_attr("import_owned")))
+
+/// Specifies that a specific C++ method should be imported as a computed
+/// property. If this macro is specified on a getter, a getter will be
+/// synthesized. If this macro is specified on a setter, both a getter and
+/// setter will be synthesized.
+///
+/// For example:
+///  ```
+///    int getX() SWIFT_COMPUTED_PROPERTY;
+///  ```
+/// Will be imported as `var x: CInt {...}`.
+#define SWIFT_COMPUTED_PROPERTY                                                \
+  __attribute__((swift_attr("import_computed_property")))
+
+#define _CXX_INTEROP_STRINGIFY(_x) #_x
+
+/// Specifies that a specific C++ `class` or `struct` conforms to a
+/// a specific Swift protocol.
+///
+/// This example shows how to use this macro to conform a class template to a
+/// Swift protocol:
+///  ```
+///    template<class T>
+///    class SWIFT_CONFORMS_TO_PROTOCOL(SwiftModule.ProtocolName)
+///    CustomClass {};
+///  ```
+// clang-format off
+#define SWIFT_CONFORMS_TO_PROTOCOL(_moduleName_protocolName)                   \
+  __attribute__((swift_attr(                                                   \
+      _CXX_INTEROP_STRINGIFY(conforms_to:_moduleName_protocolName))))
+// clang-format on
+
+#else // #if __has_attribute(swift_attr)
+
+#define SWIFT_SELF_CONTAINED
+#define SWIFT_COMPUTED_PROPERTY
+#define SWIFT_CONFORMS_TO_PROTOCOL(_moduleName_protocolName)
+
+#endif // #if __has_attribute(swift_attr)
+
+#endif // #if __has_include(<swift/bridging>)
+
+// Redefine SWIFT_NAME.
+#ifdef SWIFT_NAME
+#undef SWIFT_NAME
+#endif
+
+#if __has_attribute(swift_name)
+/// Specifies a name that will be used in Swift for this declaration instead of
+/// its original name.
+#define SWIFT_NAME(_name) __attribute__((swift_name(_name)))
+#else
+#define SWIFT_NAME(_name)
+#endif
+
+#if __has_attribute(availability)
+#define SWIFT_UNAVAILABLE(msg)                                                 \
+  __attribute__((availability(swift, unavailable, message = msg)))
+#else
+#define SWIFT_UNAVAILABLE(msg)
+#endif
+
+#if !(defined(COMPILED_WITH_SWIFT) && defined(PURE_BRIDGING_MODE))
+/// Use this macro in a `#ifdef`/`#endif` fashion to wrap code that should not
+/// be imported into Swift in pure bridging mode, e.g. because an API is
+/// irrelevant on the Swift side, or because it requires std/llvm headers, which
+/// we don't want to import in this mode.
+///
+/// - Important: Do not put a constructor inside a
+/// `NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE` block unless there already is
+/// another unconditionally available user-defined constructor!
+///
+/// Note: On Windows ARM64, how a C++ struct/class value type is
+/// returned is sensitive to conditions including whether a
+/// user-defined constructor exists, etc. See
+/// https://learn.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=msvc-170#return-values
+///
+/// So, if a C++ struct/class type is returned as a value between Swift
+/// and C++, we need to be careful to match the return convention
+/// matches between the `NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE` (C++) side
+/// and the non-`NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE` (Swift) side.
+#define NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
+#endif
+
+#endif // SWIFT_BASIC_SWIFT_BRIDGING_H
+
diff --git a/include/swift/Basic/TaskQueue.h b/include/swift/Basic/TaskQueue.h
index 758815601be9c..f40af64169098 100644
--- a/include/swift/Basic/TaskQueue.h
+++ b/include/swift/Basic/TaskQueue.h
@@ -205,8 +205,8 @@ class TaskQueue {
   /// \param Context an optional context which will be associated with the task
   /// \param SeparateErrors Controls whether error output is reported separately
   virtual void addTask(const char *ExecPath, ArrayRef<const char *> Args,
-                       ArrayRef<const char *> Env = std::nullopt,
-                       void *Context = nullptr, bool SeparateErrors = false);
+                       ArrayRef<const char *> Env = {}, void *Context = nullptr,
+                       bool SeparateErrors = false);
 
   /// Synchronously executes the tasks in the TaskQueue.
   ///
@@ -240,8 +240,8 @@ class DummyTaskQueue : public TaskQueue {
     bool SeparateErrors;
 
     DummyTask(const char *ExecPath, ArrayRef<const char *> Args,
-              ArrayRef<const char *> Env = std::nullopt,
-              void *Context = nullptr, bool SeparateErrors = false)
+              ArrayRef<const char *> Env = {}, void *Context = nullptr,
+              bool SeparateErrors = false)
         : ExecPath(ExecPath), Args(Args), Env(Env), Context(Context),
           SeparateErrors(SeparateErrors) {}
   };
@@ -254,8 +254,8 @@ class DummyTaskQueue : public TaskQueue {
   virtual ~DummyTaskQueue();
 
   void addTask(const char *ExecPath, ArrayRef<const char *> Args,
-               ArrayRef<const char *> Env = std::nullopt,
-               void *Context = nullptr, bool SeparateErrors = false) override;
+               ArrayRef<const char *> Env = {}, void *Context = nullptr,
+               bool SeparateErrors = false) override;
 
   bool
   execute(TaskBeganCallback Began = TaskBeganCallback(),
diff --git a/include/swift/Basic/Version.h b/include/swift/Basic/Version.h
index 092a4e626e518..e43ce5c7b01e5 100644
--- a/include/swift/Basic/Version.h
+++ b/include/swift/Basic/Version.h
@@ -131,6 +131,13 @@ class Version {
   /// SWIFT_VERSION_MINOR.
   static Version getCurrentLanguageVersion();
 
+  /// Returns a major version to represent the next future language mode. This
+  /// exists to make it easier to find and update clients when a new language
+  /// mode is added.
+  static constexpr unsigned getFutureMajorLanguageVersion() {
+    return 7;
+  }
+
   // List of backward-compatibility versions that we permit passing as
   // -swift-version <vers>
   static std::array<StringRef, 4> getValidEffectiveVersions() {
@@ -164,11 +171,6 @@ std::string getSwiftFullVersion(Version effectiveLanguageVersion =
 /// this Swift was built.
 StringRef getSwiftRevision();
 
-/// Is the running compiler built with a version tag for distribution?
-/// When true, \c version::getCurrentCompilerVersion returns a valid version
-/// and \c getCurrentCompilerTag returns the version tuple in string format.
-bool isCurrentCompilerTagged();
-
 /// Retrieves the distribution tag of the running compiler, if any.
 StringRef getCurrentCompilerTag();
 
diff --git a/include/swift/Bridging/ASTGen.h b/include/swift/Bridging/ASTGen.h
index afef5603a99c7..857a82edf42e7 100644
--- a/include/swift/Bridging/ASTGen.h
+++ b/include/swift/Bridging/ASTGen.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2023 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -28,13 +28,21 @@ void swift_ASTGen_addQueuedSourceFile(
 void swift_ASTGen_addQueuedDiagnostic(
     void *_Nonnull queued, void *_Nonnull state,
     BridgedStringRef text,
-    BridgedDiagnosticSeverity severity,
-    BridgedSourceLoc sourceLoc,
+    swift::DiagnosticKind severity,
+    swift::SourceLoc sourceLoc,
     BridgedStringRef categoryName,
     BridgedStringRef documentationPath,
-    const BridgedCharSourceRange *_Nullable highlightRanges,
+    const swift::CharSourceRange *_Nullable highlightRanges,
     ptrdiff_t numHighlightRanges,
     BridgedArrayRef /*BridgedFixIt*/ fixIts);
+void swift_ASTGen_renderSingleDiagnostic(
+    void *_Nonnull state,
+    BridgedStringRef text,
+    swift::DiagnosticKind severity,
+    BridgedStringRef categoryName,
+    BridgedStringRef documentationPath,
+    ssize_t colorize,
+    BridgedStringRef *_Nonnull renderedString);
 void swift_ASTGen_renderQueuedDiagnostics(
     void *_Nonnull queued, ssize_t contextSize, ssize_t colorize,
     BridgedStringRef *_Nonnull renderedString);
@@ -89,7 +97,7 @@ bool swift_ASTGen_parseRegexLiteral(
     BridgedStringRef inputPtr, size_t *_Nonnull versionOut,
     void *_Nonnull UnsafeMutableRawPointer, size_t captureStructureSize,
     BridgedRegexLiteralPatternFeatures *_Nonnull featuresOut,
-    BridgedSourceLoc diagLoc, BridgedDiagnosticEngine diagEngine);
+    swift::SourceLoc diagLoc, BridgedDiagnosticEngine diagEngine);
 
 void swift_ASTGen_freeBridgedRegexLiteralPatternFeatures(
     BridgedRegexLiteralPatternFeatures features);
@@ -109,10 +117,15 @@ intptr_t swift_ASTGen_configuredRegions(
 void swift_ASTGen_freeConfiguredRegions(
     BridgedIfConfigClauseRangeInfo *_Nullable regions, intptr_t numRegions);
 
+intptr_t swift_ASTGen_activeInEmbeddedSwift(
+    BridgedASTContext astContext,
+    void *_Nonnull sourceFile,
+    swift::SourceLoc location);
+
 bool swift_ASTGen_validateUnqualifiedLookup(
     void *_Nonnull sourceFile,
     BridgedASTContext astContext,
-    BridgedSourceLoc sourceLoc,
+    swift::SourceLoc sourceLoc,
     bool finishInSequentialScope,
     BridgedArrayRef astScopeResultRef);
 
diff --git a/include/swift/Bridging/BasicSwift.h b/include/swift/Bridging/BasicSwift.h
new file mode 100644
index 0000000000000..a2cb3f8fea606
--- /dev/null
+++ b/include/swift/Bridging/BasicSwift.h
@@ -0,0 +1,32 @@
+//===--- BasicSwift.h -------------------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2023 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_BRIDGING_BASICSWIFT_H
+#define SWIFT_BRIDGING_BASICSWIFT_H
+
+#include "swift/Basic/BasicBridging.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/// Create a new static build configuration for the given language options.
+void * _Nonnull swift_Basic_createStaticBuildConfiguration(BridgedLangOptions cLangOpts);
+
+/// Free the given static build configuration.
+void swift_Basic_freeStaticBuildConfiguration(void * _Nonnull staticBuildConfiguration);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // SWIFT_BRIDGING_BASICSWIFT_H
diff --git a/include/swift/Bridging/MacroEvaluation.h b/include/swift/Bridging/MacroEvaluation.h
index 1df6e130ee1db..650accc61122c 100644
--- a/include/swift/Bridging/MacroEvaluation.h
+++ b/include/swift/Bridging/MacroEvaluation.h
@@ -14,6 +14,7 @@
 #define SWIFT_BRIDGING_MACROS_H
 
 #include "swift/Basic/BasicBridging.h"
+#include "swift/AST/ASTBridging.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -40,13 +41,13 @@ void swift_Macros_freeExpansionReplacements(
     ptrdiff_t *_Nullable replacementsPtr, ptrdiff_t numReplacements);
 
 ptrdiff_t swift_Macros_expandFreestandingMacro(
-    void *_Nonnull diagEngine, const void *_Nonnull macro,
+    BridgedASTContext cContext, const void *_Nonnull macro,
     const char *_Nonnull discriminator, uint8_t rawMacroRole,
     void *_Nonnull sourceFile, const void *_Nullable sourceLocation,
     BridgedStringRef *_Nonnull evaluatedSourceOut);
 
 ptrdiff_t swift_Macros_expandAttachedMacro(
-    void *_Nonnull diagEngine, const void *_Nonnull macro,
+    BridgedASTContext cContext, const void *_Nonnull macro,
     const char *_Nonnull discriminator, const char *_Nonnull qualifiedType,
     const char *_Nonnull conformances, uint8_t rawMacroRole,
     void *_Nonnull customAttrSourceFile,
diff --git a/include/swift/ClangImporter/ClangImporter.h b/include/swift/ClangImporter/ClangImporter.h
index de1091ba12cd5..ae932bf689192 100644
--- a/include/swift/ClangImporter/ClangImporter.h
+++ b/include/swift/ClangImporter/ClangImporter.h
@@ -19,6 +19,7 @@
 #include "swift/AST/Attr.h"
 #include "swift/AST/AttrKind.h"
 #include "swift/AST/ClangModuleLoader.h"
+#include "clang/AST/Attr.h"
 #include "clang/Basic/Specifiers.h"
 #include "llvm/Support/VirtualFileSystem.h"
 
@@ -64,12 +65,14 @@ namespace tooling {
 namespace dependencies {
   struct ModuleDeps;
   struct TranslationUnitDeps;
+  enum class ModuleOutputKind;
   using ModuleDepsGraph = std::vector<ModuleDeps>;
 }
 }
 }
 
 namespace swift {
+enum class ResultConvention : uint8_t;
 class ASTContext;
 class CompilerInvocation;
 class ClangImporterOptions;
@@ -162,8 +165,7 @@ class ClangImporter final : public ClangModuleLoader {
 
   bool requiresBuiltinHeadersInSystemModules = false;
 
-  ClangImporter(ASTContext &ctx,
-                DependencyTracker *tracker,
+  ClangImporter(ASTContext &ctx, DependencyTracker *tracker,
                 DWARFImporterDelegate *dwarfImporterDelegate);
 
   /// Creates a clone of Clang importer's compiler instance that has been
@@ -195,8 +197,8 @@ class ClangImporter final : public ClangModuleLoader {
   /// \returns a new Clang module importer, or null (with a diagnostic) if
   /// an error occurred.
   static std::unique_ptr<ClangImporter>
-  create(ASTContext &ctx,
-         std::string swiftPCHHash = "", DependencyTracker *tracker = nullptr,
+  create(ASTContext &ctx, std::string swiftPCHHash = "",
+         DependencyTracker *tracker = nullptr,
          DWARFImporterDelegate *dwarfImporterDelegate = nullptr,
          bool ignoreFileMapping = false);
 
@@ -209,8 +211,7 @@ class ClangImporter final : public ClangModuleLoader {
                        bool ignoreClangTarget = false);
 
   std::vector<std::string>
-  getClangDepScanningInvocationArguments(ASTContext &ctx,
-      std::optional<StringRef> sourceFileName = std::nullopt);
+  getClangDepScanningInvocationArguments(ASTContext &ctx);
 
   static std::unique_ptr<clang::CompilerInvocation>
   createClangInvocation(ClangImporter *importer,
@@ -428,6 +429,16 @@ class ClangImporter final : public ClangModuleLoader {
                             bool trackParsedSymbols = false,
                             bool implicitImport = false);
 
+  /// Bind the bridging header content to the module.
+  ///
+  /// \param adapter The module that depends on the contents of this header.
+  /// \param diagLoc A location to attach any diagnostics to if import fails.
+  ///
+  /// \returns true if there was an error importing the header.
+  ///
+  /// \sa importBridgingHeader
+  bool bindBridgingHeader(ModuleDecl *adapter, SourceLoc diagLoc);
+
   /// Returns the module that contains imports and declarations from all loaded
   /// Objective-C header files.
   ///
@@ -462,11 +473,6 @@ class ClangImporter final : public ClangModuleLoader {
   /// Reads the original source file name from PCH.
   std::string getOriginalSourceFile(StringRef PCHFilename);
 
-  /// Add clang dependency file names.
-  ///
-  /// \param files The list of file to append dependencies to.
-  void addClangInvovcationDependencies(std::vector<std::string> &files);
-
   /// Makes a temporary replica of the ClangImporter's CompilerInstance, reads a
   /// module map into the replica and emits a PCM file for one of the modules it
   /// declares. Delegates to clang for everything except construction of the
@@ -486,55 +492,11 @@ class ClangImporter final : public ClangModuleLoader {
 
   void verifyAllModules() override;
 
-  using RemapPathCallback = llvm::function_ref<std::string(StringRef)>;
-  llvm::SmallVector<std::pair<ModuleDependencyID, ModuleDependencyInfo>, 1>
-  bridgeClangModuleDependencies(
-      clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-      clang::tooling::dependencies::ModuleDepsGraph &clangDependencies,
-      StringRef moduleOutputPath, StringRef stableModuleOutputPath,
-      RemapPathCallback remapPath = nullptr);
-
-  llvm::SmallVector<std::pair<ModuleDependencyID, ModuleDependencyInfo>, 1>
-  getModuleDependencies(Identifier moduleName, StringRef moduleOutputPath, StringRef sdkModuleOutputPath,
-                        const llvm::DenseSet<clang::tooling::dependencies::ModuleID> &alreadySeenClangModules,
-                        clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-                        InterfaceSubContextDelegate &delegate,
-                        llvm::PrefixMapper *mapper,
-                        bool isTestableImport = false) override;
-
-  void recordBridgingHeaderOptions(
-      ModuleDependencyInfo &MDI,
-      const clang::tooling::dependencies::TranslationUnitDeps &deps);
-
-  void getBridgingHeaderOptions(
+  static void getBridgingHeaderOptions(
+      const ASTContext &ctx,
       const clang::tooling::dependencies::TranslationUnitDeps &deps,
       std::vector<std::string> &swiftArgs);
 
-  /// Query dependency information for header dependencies
-  /// of a binary Swift module.
-  ///
-  /// \param moduleID the name of the Swift module whose dependency
-  /// information will be augmented with information about the given
-  /// textual header inputs.
-  ///
-  /// \param headerPath the path to the header to be scanned.
-  ///
-  /// \param clangScanningTool The clang dependency scanner.
-  ///
-  /// \param cache The module dependencies cache to update, with information
-  /// about new Clang modules discovered along the way.
-  ///
-  /// \returns \c true if an error occurred, \c false otherwise
-  bool getHeaderDependencies(
-      ModuleDependencyID moduleID, std::optional<StringRef> headerPath,
-      std::optional<llvm::MemoryBufferRef> sourceBuffer,
-      clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-      ModuleDependenciesCache &cache,
-      ModuleDependencyIDSetVector &headerClangModuleDependencies,
-      std::vector<std::string> &headerFileInputs,
-      std::vector<std::string> &bridgingHeaderCommandLine,
-      std::optional<std::string> &includeTreeID);
-
   clang::TargetInfo &getModuleAvailabilityTarget() const override;
   clang::ASTContext &getClangASTContext() const override;
   clang::Preprocessor &getClangPreprocessor() const override;
@@ -654,6 +616,8 @@ class ClangImporter final : public ClangModuleLoader {
 
   FuncDecl *getDefaultArgGenerator(const clang::ParmVarDecl *param) override;
 
+  FuncDecl *getAvailabilityDomainPredicate(const clang::VarDecl *var) override;
+
   bool isAnnotatedWith(const clang::CXXMethodDecl *method, StringRef attr);
 
   /// Find the lookup table that corresponds to the given Clang module.
@@ -672,6 +636,8 @@ class ClangImporter final : public ClangModuleLoader {
   ValueDecl *importBaseMemberDecl(ValueDecl *decl, DeclContext *newContext,
                                   ClangInheritanceInfo inheritance) override;
 
+  ValueDecl *getOriginalForClonedMember(const ValueDecl *decl) override;
+
   /// Emits diagnostics for any declarations named name
   /// whose direct declaration context is a TU.
   void diagnoseTopLevelValue(const DeclName &name) override;
@@ -680,12 +646,6 @@ class ClangImporter final : public ClangModuleLoader {
   /// of the provided baseType.
   void diagnoseMemberValue(const DeclName &name, const Type &baseType) override;
 
-  /// Enable the symbolic import experimental feature for the given callback.
-  void withSymbolicFeatureEnabled(llvm::function_ref<void(void)> callback);
-
-  /// Returns true when the symbolic import experimental feature is enabled.
-  bool isSymbolicImportEnabled() const;
-
   const clang::TypedefType *getTypeDefForCXXCFOptionsDefinition(
       const clang::Decl *candidateDecl) override;
 
@@ -710,6 +670,24 @@ getModuleCachePathFromClang(const clang::CompilerInstance &Instance);
 bool isCompletionHandlerParamName(StringRef paramName);
 
 namespace importer {
+/// Returns true if the given C/C++ reference type uses "immortal"
+/// retain/release functions.
+bool hasImmortalAttrs(const clang::RecordDecl *decl);
+
+struct ReturnOwnershipInfo {
+  ReturnOwnershipInfo(const clang::NamedDecl *decl);
+
+  bool hasRetainAttr() const {
+    return hasReturnsRetained || hasReturnsUnretained;
+  }
+  bool hasConflictingAttr() const {
+    return hasReturnsRetained && hasReturnsUnretained;
+  }
+
+private:
+  bool hasReturnsRetained = false;
+  bool hasReturnsUnretained = false;
+};
 
 /// Returns true if the given module has a 'cplusplus' requirement.
 bool requiresCPlusPlus(const clang::Module *module);
@@ -732,12 +710,13 @@ getCxxReferencePointeeTypeOrNone(const clang::Type *type);
 /// Returns true if the given type is a C++ `const` reference type.
 bool isCxxConstReferenceType(const clang::Type *type);
 
+/// Determine whether the given Clang record declaration has one of the
+/// attributes that makes it import as a reference types.
+bool hasImportAsRefAttr(const clang::RecordDecl *decl);
+
 /// Determine whether this typedef is a CF type.
 bool isCFTypeDecl(const clang::TypedefNameDecl *Decl);
 
-/// Determine whether type is a c++ foreign reference type.
-bool isForeignReferenceTypeWithoutImmortalAttrs(const clang::QualType type);
-
 /// Determine the imported CF type for the given typedef-name, or the empty
 /// string if this is not an imported CF type name.
 llvm::StringRef getCFTypeName(const clang::TypedefNameDecl *decl);
@@ -773,6 +752,116 @@ getPrivateFileIDAttrs(const clang::CXXRecordDecl *decl);
 ///
 /// Returns false if \a decl was not imported by ClangImporter.
 bool declIsCxxOnly(const Decl *decl);
+
+/// Is this DeclContext an `enum` that represents a C++ namespace?
+bool isClangNamespace(const DeclContext *dc);
+
+/// For some \a templatedClass that inherits from \a base, whether they are
+/// derived from the same class template.
+///
+/// This kind of circular inheritance can happen when a templated class inherits
+/// from a specialization of itself, e.g.:
+///
+///     template <typename T> class C;
+///     template <> class C<void> { /* ... */ };
+///     template <typename T> class C<T> : C<void> { /* ... */ };
+///
+/// Checking for this kind of scenario is necessary for avoiding infinite
+/// recursion during symbolic imports (importSymbolicCXXDecls), where
+/// specialized class templates are instead imported as unspecialized.
+bool isSymbolicCircularBase(const clang::CXXRecordDecl *templatedClass,
+                            const clang::RecordDecl *base);
+
+/// Match a `[[swift_attr("...")]]` annotation on the given Clang decl.
+///
+/// \param decl The Clang declaration to inspect.
+/// \param patterns List of (attribute name, value) pairs.
+/// \returns The value for the first matching attribute, or `std::nullopt`.
+template <typename T>
+std::optional<T>
+matchSwiftAttr(const clang::Decl *decl,
+               llvm::ArrayRef<std::pair<llvm::StringRef, T>> patterns) {
+  if (!decl || !decl->hasAttrs())
+    return std::nullopt;
+
+  for (const auto *attr : decl->getAttrs()) {
+    if (const auto *swiftAttr = llvm::dyn_cast<clang::SwiftAttrAttr>(attr)) {
+      for (const auto &p : patterns) {
+        if (swiftAttr->getAttribute() == p.first)
+          return p.second;
+      }
+    }
+  }
+  return std::nullopt;
+}
+
+/// Like `matchSwiftAttr`, but also searches C++ base classes.
+///
+/// \param decl The Clang declaration to inspect.
+/// \param patterns List of (attribute name, value) pairs.
+/// \returns The matched value from this decl or its bases, or `std::nullopt`.
+template <typename T>
+std::optional<T> matchSwiftAttrConsideringInheritance(
+    const clang::Decl *decl,
+    llvm::ArrayRef<std::pair<llvm::StringRef, T>> patterns) {
+  if (!decl)
+    return std::nullopt;
+
+  if (auto match = matchSwiftAttr<T>(decl, patterns))
+    return match;
+
+  if (const auto *recordDecl = llvm::dyn_cast<clang::CXXRecordDecl>(decl)) {
+    std::optional<T> result;
+    if (recordDecl->isCompleteDefinition()) {
+      recordDecl->forallBases([&](const clang::CXXRecordDecl *base) -> bool {
+        if (auto baseMatch = matchSwiftAttr<T>(base, patterns)) {
+          result = baseMatch;
+          return false;
+        }
+
+        return true;
+      });
+
+      return result;
+    }
+  }
+
+  return std::nullopt;
+}
+
+/// Matches a `swift_attr("...")` on the record type pointed to by the given
+/// Clang type, searching base classes if it's a C++ class.
+///
+/// \param type A Clang pointer or reference type.
+/// \param patterns List of attribute name-value pairs to match.
+/// \returns Matched value or std::nullopt.
+template <typename T>
+std::optional<T> matchSwiftAttrOnRecordPtr(
+    const clang::QualType &type,
+    llvm::ArrayRef<std::pair<llvm::StringRef, T>> patterns) {
+  clang::QualType pointeeType;
+  if (const auto *ptrType = type->getAs<clang::PointerType>()) {
+    pointeeType = ptrType->getPointeeType();
+  } else if (const auto *refType = type->getAs<clang::ReferenceType>()) {
+    pointeeType = refType->getPointeeType();
+  } else {
+    return std::nullopt;
+  }
+
+  if (const auto *recordDecl = pointeeType->getAsRecordDecl()) {
+    return matchSwiftAttrConsideringInheritance<T>(recordDecl, patterns);
+  }
+  return std::nullopt;
+}
+
+/// Determines the C++ reference ownership convention for the return value
+/// using `SWIFT_RETURNS_(UN)RETAINED` on the API; falls back to
+/// `SWIFT_RETURNED_AS_(UN)RETAINED_BY_DEFAULT` on the pointee record type.
+///
+/// \param decl The Clang function or method declaration to inspect.
+/// \returns Matched `ResultConvention`, or `std::nullopt` if none applies.
+std::optional<ResultConvention>
+getCxxRefConventionWithAttrs(const clang::Decl *decl);
 } // namespace importer
 
 struct ClangInvocationFileMapping {
@@ -793,10 +882,19 @@ struct ClangInvocationFileMapping {
 /// `suppressDiagnostic` prevents us from emitting warning messages when we
 /// are unable to find headers.
 ClangInvocationFileMapping getClangInvocationFileMapping(
-    ASTContext &ctx,
+    const ASTContext &ctx,
     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> vfs = nullptr,
     bool suppressDiagnostic = false);
 
+/// Apply the given file mapping to the specified 'fileSystem', used
+/// primarily to inject modulemaps on platforms with non-modularized
+/// platform libraries.
+ClangInvocationFileMapping applyClangInvocationMapping(
+    const ASTContext &ctx,
+    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> baseVFS,
+    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &fileSystem,
+    bool suppressDiagnostics = false);
+
 /// Information used to compute the access level of inherited C++ members.
 class ClangInheritanceInfo {
   /// The cumulative inheritance access specifier, that is used to compute the
diff --git a/include/swift/ClangImporter/ClangImporterRequests.h b/include/swift/ClangImporter/ClangImporterRequests.h
index e05db6edf2378..fe83d0fae0405 100644
--- a/include/swift/ClangImporter/ClangImporterRequests.h
+++ b/include/swift/ClangImporter/ClangImporterRequests.h
@@ -342,15 +342,9 @@ class ObjCInterfaceAndImplementationRequest
 };
 
 enum class CxxRecordSemanticsKind {
-  Trivial,
-  Owned,
-  MoveOnly,
+  Value,
   Reference,
   Iterator,
-  // A record that is either not copyable/movable or not destructible.
-  MissingLifetimeOperation,
-  // A record that has no copy and no move operations
-  UnavailableConstructors,
   // A C++ record that represents a Swift class type exposed to C++ from Swift.
   SwiftClassType
 };
@@ -576,10 +570,91 @@ class ClangTypeEscapability
 void simple_display(llvm::raw_ostream &out, EscapabilityLookupDescriptor desc);
 SourceLoc extractNearestSourceLoc(EscapabilityLookupDescriptor desc);
 
+// Swift value semantics of C++ types
+// These are usually equivalent, with the exception of references.
+// When a reference type is copied, the pointer’s value is copied rather than
+// the object’s storage. This means reference types can be imported as
+// copyable to Swift, even when they are non-copyable in C++.
+enum class CxxValueSemanticsKind {
+  Unknown,
+  Copyable,
+  MoveOnly,
+  // A record that is either not copyable/movable or not destructible.
+  MissingLifetimeOperation,
+  // A record that has no copy and no move operations
+  UnavailableConstructors,
+};
+
+struct CxxValueSemanticsDescriptor final {
+  const clang::Type *type;
+  ClangImporter::Implementation *importerImpl;
+
+  friend llvm::hash_code hash_value(const CxxValueSemanticsDescriptor &desc) {
+    return llvm::hash_combine(desc.type);
+  }
+
+  friend bool operator==(const CxxValueSemanticsDescriptor &lhs,
+                         const CxxValueSemanticsDescriptor &rhs) {
+    return lhs.type == rhs.type;
+  }
+
+  friend bool operator!=(const CxxValueSemanticsDescriptor &lhs,
+                         const CxxValueSemanticsDescriptor &rhs) {
+    return !(lhs == rhs);
+  }
+};
+
+class CxxValueSemantics
+    : public SimpleRequest<CxxValueSemantics,
+                           CxxValueSemanticsKind(
+                               CxxValueSemanticsDescriptor),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+  bool isCached() const { return true; }
+
+private:
+  friend SimpleRequest;
+
+  CxxValueSemanticsKind evaluate(Evaluator &evaluator,
+                                 CxxValueSemanticsDescriptor desc) const;
+};
+
+void simple_display(llvm::raw_ostream &out, CxxValueSemanticsDescriptor desc);
+SourceLoc extractNearestSourceLoc(CxxValueSemanticsDescriptor desc);
+
+struct CxxDeclExplicitSafetyDescriptor final {
+  const clang::Decl *decl;
+  bool isClass;
+
+  CxxDeclExplicitSafetyDescriptor(const clang::Decl *decl, bool isClass)
+      : decl(decl), isClass(isClass) {}
+
+  friend llvm::hash_code
+  hash_value(const CxxDeclExplicitSafetyDescriptor &desc) {
+    return llvm::hash_combine(desc.decl, desc.isClass);
+  }
+
+  friend bool operator==(const CxxDeclExplicitSafetyDescriptor &lhs,
+                         const CxxDeclExplicitSafetyDescriptor &rhs) {
+    return lhs.decl == rhs.decl && lhs.isClass == rhs.isClass;
+  }
+
+  friend bool operator!=(const CxxDeclExplicitSafetyDescriptor &lhs,
+                         const CxxDeclExplicitSafetyDescriptor &rhs) {
+    return !(lhs == rhs);
+  }
+};
+
+void simple_display(llvm::raw_ostream &out,
+                    CxxDeclExplicitSafetyDescriptor desc);
+SourceLoc extractNearestSourceLoc(CxxDeclExplicitSafetyDescriptor desc);
+
 /// Determine the safety of the given Clang declaration.
 class ClangDeclExplicitSafety
     : public SimpleRequest<ClangDeclExplicitSafety,
-                           ExplicitSafety(SafeUseOfCxxDeclDescriptor),
+                           ExplicitSafety(CxxDeclExplicitSafetyDescriptor),
                            RequestFlags::Cached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -592,7 +667,8 @@ class ClangDeclExplicitSafety
   friend SimpleRequest;
 
   // Evaluation.
-  ExplicitSafety evaluate(Evaluator &evaluator, SafeUseOfCxxDeclDescriptor desc) const;
+  ExplicitSafety evaluate(Evaluator &evaluator,
+                          CxxDeclExplicitSafetyDescriptor desc) const;
 };
 
 #define SWIFT_TYPEID_ZONE ClangImporter
diff --git a/include/swift/ClangImporter/ClangImporterTypeIDZone.def b/include/swift/ClangImporter/ClangImporterTypeIDZone.def
index b4ea68a4053a2..0d562311a9c72 100644
--- a/include/swift/ClangImporter/ClangImporterTypeIDZone.def
+++ b/include/swift/ClangImporter/ClangImporterTypeIDZone.def
@@ -45,6 +45,9 @@ SWIFT_REQUEST(ClangImporter, CustomRefCountingOperation,
 SWIFT_REQUEST(ClangImporter, ClangTypeEscapability,
               CxxEscapability(EscapabilityLookupDescriptor), Cached,
               NoLocationInfo)
+SWIFT_REQUEST(ClangImporter, CxxValueSemantics,
+              CxxValueSemanticsKind(CxxValueSemanticsDescriptor), Cached,
+              NoLocationInfo)
 SWIFT_REQUEST(ClangImporter, ClangDeclExplicitSafety,
-              ExplicitSafety(SafeUseOfCxxDeclDescriptor), Cached,
+              ExplicitSafety(CxxDeclExplicitSafetyDescriptor), Cached,
               NoLocationInfo)
diff --git a/include/swift/ClangImporter/ClangModule.h b/include/swift/ClangImporter/ClangModule.h
index c27cc2ecf2a2a..85536be1ec5a1 100644
--- a/include/swift/ClangImporter/ClangModule.h
+++ b/include/swift/ClangImporter/ClangModule.h
@@ -141,6 +141,10 @@ class ClangModuleUnit final : public LoadedFile {
   }
 };
 
+// Strips the inline namespaces from inner until we reach outer or a
+// non-inline namespace. Returns the stripped nominal type or null when
+// something unexpected happened during stripping.
+NominalType *stripInlineNamespaces(NominalType *outer, NominalType *inner);
 }
 
 #endif
diff --git a/include/swift/ClangImporter/SwiftAbstractBasicReader.h b/include/swift/ClangImporter/SwiftAbstractBasicReader.h
index b5063c1c43493..8e31db659d2c1 100644
--- a/include/swift/ClangImporter/SwiftAbstractBasicReader.h
+++ b/include/swift/ClangImporter/SwiftAbstractBasicReader.h
@@ -64,6 +64,11 @@ class DataStreamBasicReader
     return uint32_t(asImpl().readUInt64());
   }
 
+  clang::UnsignedOrNone readUnsignedOrNone() {
+    return clang::UnsignedOrNone::fromInternalRepresentation(
+        unsigned(asImpl().readUInt64()));
+  }
+
   clang::Selector readSelector() {
     uint64_t numArgsPlusOne = asImpl().readUInt64();
 
diff --git a/include/swift/ClangImporter/SwiftAbstractBasicWriter.h b/include/swift/ClangImporter/SwiftAbstractBasicWriter.h
index be8e2bf3c0e57..f636cba5907ba 100644
--- a/include/swift/ClangImporter/SwiftAbstractBasicWriter.h
+++ b/include/swift/ClangImporter/SwiftAbstractBasicWriter.h
@@ -61,6 +61,10 @@ class DataStreamBasicWriter
     asImpl().writeUInt64(uint64_t(value));
   }
 
+  void writeUnsignedOrNone(clang::UnsignedOrNone value) {
+    asImpl().writeUInt64(uint64_t(value.toInternalRepresentation()));
+  }
+
   void writeSelector(clang::Selector selector) {
     if (selector.isNull()) {
       asImpl().writeUInt64(0);
diff --git a/include/swift/Demangling/Demangle.h b/include/swift/Demangling/Demangle.h
index 5e1d153b77545..12606c6520c03 100644
--- a/include/swift/Demangling/Demangle.h
+++ b/include/swift/Demangling/Demangle.h
@@ -19,9 +19,11 @@
 #ifndef SWIFT_DEMANGLING_DEMANGLE_H
 #define SWIFT_DEMANGLING_DEMANGLE_H
 
+#include "swift/Demangling/Demangle.h"
 #include "swift/Demangling/Errors.h"
 #include "swift/Demangling/ManglingFlavor.h"
 #include "swift/Demangling/NamespaceMacros.h"
+#include "swift/Strings.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Compiler.h"
 
@@ -99,6 +101,7 @@ struct DemangleOptions {
 
 class Node;
 using NodePointer = Node *;
+class NodePrinter;
 
 enum class FunctionSigSpecializationParamKind : unsigned {
   // Option Flags use bits 0-5. This give us 6 bits implying 64 entries to
@@ -113,6 +116,8 @@ enum class FunctionSigSpecializationParamKind : unsigned {
   BoxToStack = 7,
   InOutToOut = 8,
   ConstantPropKeyPath = 9,
+  ConstantPropStruct = 10,
+  ClosurePropPreviousArg = 11,
 
   // Option Set Flags use bits 6-31. This gives us 26 bits to use for option
   // flags.
@@ -190,6 +195,7 @@ class Node {
   };
 
   using IndexType = uint64_t;
+  using RemoteAddressType = std::pair<uint64_t, uint8_t>;
 
   friend class NodeFactory;
   
@@ -206,14 +212,20 @@ class Node {
     IndexType Index;
     NodePointer InlineChildren[2];
     NodeVector Children;
+    RemoteAddressType RemoteAddress;
   };
 
 
   Kind NodeKind;
 
   enum class PayloadKind : uint8_t {
-    None = 0, OneChild = 1, TwoChildren = 2,
-    Text, Index, ManyChildren
+    None = 0,
+    OneChild = 1,
+    TwoChildren = 2,
+    Text,
+    Index,
+    ManyChildren,
+    RemoteAddress
   };
   PayloadKind NodePayloadKind;
 
@@ -228,6 +240,10 @@ class Node {
       : NodeKind(k), NodePayloadKind(PayloadKind::Index) {
     Index = index;
   }
+  Node(Kind k, uint64_t remoteAddress, uint8_t addressSpace)
+      : NodeKind(k), NodePayloadKind(PayloadKind::RemoteAddress) {
+    RemoteAddress = {remoteAddress, addressSpace};
+  }
   Node(const Node &) = delete;
   Node &operator=(const Node &) = delete;
 
@@ -281,6 +297,14 @@ class Node {
     return Index;
   }
 
+  bool hasRemoteAddress() const {
+    return NodePayloadKind == PayloadKind::RemoteAddress;
+  }
+  std::pair<uint64_t, uint8_t> getRemoteAddress() const {
+    assert(hasRemoteAddress());
+    return RemoteAddress;
+  }
+
   using iterator = const NodePointer *;
 
   size_t getNumChildren() const {
@@ -465,16 +489,26 @@ class Context {
   /// The lifetime of the returned node tree ends with the lifetime of the
   /// context or with a call of clear().
   NodePointer demangleTypeAsNode(llvm::StringRef MangledName);
-  
+
   /// Demangle the given symbol and return the readable name.
   ///
   /// \param MangledName The mangled symbol string, which start a mangling
   /// prefix: _T, _T0, $S, _$S.
   ///
   /// \returns The demangled string.
-  std::string demangleSymbolAsString(
-      llvm::StringRef MangledName,
-      const DemangleOptions &Options = DemangleOptions());
+  std::string
+  demangleSymbolAsString(llvm::StringRef MangledName,
+                         const DemangleOptions &Options = DemangleOptions());
+
+  /// Demangle the given symbol and store the result in the `printer`.
+  ///
+  /// \param MangledName The mangled symbol string, which start a mangling
+  /// prefix: _T, _T0, $S, _$S.
+  /// \param Printer The NodePrinter that will be used to demangle the symbol.
+  ///
+  /// \returns The demangled string.
+  void demangleSymbolAsString(llvm::StringRef MangledName,
+                              NodePrinter &Printer);
 
   /// Demangle the given type and return the readable name.
   ///
@@ -533,6 +567,16 @@ std::string
 demangleSymbolAsString(const char *mangledName, size_t mangledNameLength,
                        const DemangleOptions &options = DemangleOptions());
 
+/// Standalone utility function to demangle the given symbol as string. The
+/// demangled string is stored in the `printer`.
+///
+/// If performance is an issue when demangling multiple symbols,
+/// \param mangledName The mangled name string pointer.
+/// \param mangledNameLength The length of the mangledName string.
+/// \param printer The NodePrinter that will be used to demangle the symbol.
+void demangleSymbolAsString(const llvm::StringRef mangledName,
+                            NodePrinter &printer);
+
 /// Standalone utility function to demangle the given symbol as string.
 ///
 /// If performance is an issue when demangling multiple symbols,
@@ -545,7 +589,7 @@ demangleSymbolAsString(const std::string &mangledName,
   return demangleSymbolAsString(mangledName.data(), mangledName.size(),
                                 options);
 }
-  
+
 /// Standalone utility function to demangle the given symbol as string.
 ///
 /// If performance is an issue when demangling multiple symbols,
@@ -626,7 +670,7 @@ struct [[nodiscard]] ManglingError {
     InvalidImplCoroutineKind,
     InvalidImplFunctionAttribute,
     InvalidImplParameterConvention,
-    InvalidImplParameterSending,
+    InvalidImplParameterAttr,
     InvalidMetatypeRepresentation,
     MultiByteRelatedEntity,
     BadValueWitnessKind,
@@ -725,13 +769,19 @@ ManglingErrorOr<const char *> mangleNodeAsObjcCString(NodePointer node,
 /// \endcode
 ///
 /// \param Root A pointer to a parse tree generated by the demangler.
-/// \param Options An object encapsulating options to use to perform this demangling.
+/// \param Options An object encapsulating options to use to perform this
+/// demangling.
 ///
 /// \returns A string representing the demangled name.
-///
 std::string nodeToString(NodePointer Root,
                          const DemangleOptions &Options = DemangleOptions());
 
+/// Transform the node structure to a string, which is stored in the `Printer`.
+///
+/// \param Root A pointer to a parse tree generated by the demangler.
+/// \param Printer A NodePrinter used to pretty print the demangled Node.
+void nodeToString(NodePointer Root, NodePrinter &Printer);
+
 /// Transforms a mangled key path accessor thunk helper
 /// into the identfier/subscript that would be used to invoke it in swift code.
 std::string keyPathSourceString(const char *MangledName,
@@ -777,11 +827,14 @@ class DemanglerPrinter {
 
   llvm::StringRef getStringRef() const { return Stream; }
 
+  size_t getStreamLength() { return Stream.length(); }
+
   /// Shrinks the buffer.
   void resetSize(size_t toPos) {
     assert(toPos <= Stream.size());
     Stream.resize(toPos);
   }
+
 private:
   std::string Stream;
 };
@@ -818,6 +871,162 @@ std::string mangledNameForTypeMetadataAccessor(
     llvm::StringRef moduleName, llvm::StringRef typeName, Node::Kind typeKind,
     Mangle::ManglingFlavor Flavor = Mangle::ManglingFlavor::Default);
 
+/// Base class for printing a Swift demangled node tree.
+///
+/// NodePrinter is used to convert demangled Swift symbol nodes into
+/// human-readable string representations. It handles formatting, indentation,
+/// and Swift-specific syntax.
+///
+/// The virtual methods in this class are meant to be overriden to allow
+/// external consumers (e.g lldb) to track the ranges of components of the
+/// demangled name.
+class NodePrinter {
+protected:
+  DemanglerPrinter Printer;
+  DemangleOptions Options;
+  bool SpecializationPrefixPrinted = false;
+  bool isValid = true;
+
+public:
+  NodePrinter(DemangleOptions options) : Options(options) {}
+
+  virtual ~NodePrinter() = default;
+
+  virtual void printRoot(NodePointer root) {
+    isValid = true;
+    print(root, 0);
+  }
+
+  std::string takeString() {
+    if (isValid)
+      return std::move(Printer).str();
+    return "";
+  }
+
+protected:
+  static const unsigned MaxDepth = 768;
+
+  size_t getStreamLength() { return Printer.getStreamLength(); }
+
+  /// Called when the node tree in valid.
+  ///
+  /// The demangler already catches most error cases and mostly produces valid
+  /// node trees. But some cases are difficult to catch in the demangler and
+  /// instead the NodePrinter bails.
+  void setInvalid() { isValid = false; }
+
+  void printChildren(Node::iterator begin, Node::iterator end, unsigned depth,
+                     const char *sep = nullptr);
+
+  void printChildren(NodePointer Node, unsigned depth,
+                     const char *sep = nullptr);
+
+  NodePointer getFirstChildOfKind(NodePointer Node, Node::Kind kind);
+
+  void printBoundGenericNoSugar(NodePointer Node, unsigned depth);
+
+  void printOptionalIndex(NodePointer node);
+
+  static bool isSwiftModule(NodePointer node) {
+    return (node->getKind() == Node::Kind::Module &&
+            node->getText() == STDLIB_NAME);
+  }
+
+  static bool isIdentifier(NodePointer node, StringRef desired) {
+    return (node->getKind() == Node::Kind::Identifier &&
+            node->getText() == desired);
+  }
+
+  bool printContext(NodePointer Context);
+
+  enum class SugarType {
+    None,
+    Optional,
+    ImplicitlyUnwrappedOptional,
+    Array,
+    Dictionary
+  };
+
+  enum class TypePrinting { NoType, WithColon, FunctionStyle };
+
+  /// Determine whether this is a "simple" type, from the type-simple
+  /// production.
+  bool isSimpleType(NodePointer Node);
+
+  void printWithParens(NodePointer type, unsigned depth);
+
+  SugarType findSugar(NodePointer Node);
+
+  void printBoundGeneric(NodePointer Node, unsigned depth);
+
+  NodePointer getChildIf(NodePointer Node, Node::Kind Kind);
+
+  virtual void printFunctionParameters(NodePointer LabelList,
+                                       NodePointer ParameterType,
+                                       unsigned depth, bool showTypes);
+
+  void printFunctionType(NodePointer LabelList, NodePointer node,
+                         unsigned depth);
+
+  void printImplFunctionType(NodePointer fn, unsigned depth);
+
+  virtual void printGenericSignature(NodePointer Node, unsigned depth);
+
+  void printFunctionSigSpecializationParams(NodePointer Node, unsigned depth);
+  void printNextParamChildNode(NodePointer nd, unsigned &idx,
+                               FunctionSigSpecializationParamKind kind,
+                               unsigned depth);
+
+  void printSpecializationPrefix(NodePointer node, StringRef Description,
+                                 unsigned depth,
+                                 StringRef ParamPrefix = StringRef());
+
+  /// The main big print function.
+  NodePointer print(NodePointer Node, unsigned depth,
+                    bool asPrefixContext = false);
+
+  NodePointer printAbstractStorage(NodePointer Node, unsigned depth,
+                                   bool asPrefixContent, StringRef ExtraName);
+
+  /// Utility function to print entities.
+  ///
+  /// \param Entity The entity node to print
+  /// \param depth The depth in the print() call tree.
+  /// \param asPrefixContext Should the entity printed as a context which as a
+  ///        prefix to another entity, e.g. the Abc in Abc.def()
+  /// \param TypePr How should the type of the entity be printed, if at all.
+  ///        E.g. with a colon for properties or as a function type.
+  /// \param hasName Does the entity has a name, e.g. a function in contrast to
+  ///        an initializer.
+  /// \param ExtraName An extra name added to the entity name (if any).
+  /// \param ExtraIndex An extra index added to the entity name (if any),
+  ///        e.g. closure #1
+  /// \param OverwriteName If non-empty, print this name instead of the one
+  ///        provided by the node. Gets printed even if hasName is false.
+  /// \return If a non-null node is returned it's a context which must be
+  ///         printed in postfix-form after the entity: "<entity> in <context>".
+  NodePointer printEntity(NodePointer Entity, unsigned depth,
+                          bool asPrefixContext, TypePrinting TypePr,
+                          bool hasName, StringRef ExtraName = "",
+                          int ExtraIndex = -1, StringRef OverwriteName = "");
+
+  virtual void printFunctionName(bool hasName, llvm::StringRef &OverwriteName,
+                                 llvm::StringRef &ExtraName, bool MultiWordName,
+                                 int &ExtraIndex,
+                                 swift::Demangle::NodePointer Entity,
+                                 unsigned int depth);
+
+  /// Print the type of an entity.
+  ///
+  /// \param Entity The entity.
+  /// \param type The type of the entity.
+  /// \param genericFunctionTypeList If not null, the generic argument types
+  ///           which is printed in the generic signature.
+  /// \param depth The depth in the print() call tree.
+  void printEntityType(NodePointer Entity, NodePointer type,
+                       NodePointer genericFunctionTypeList, unsigned depth);
+};
+
 SWIFT_END_INLINE_NAMESPACE
 } // end namespace Demangle
 } // end namespace swift
diff --git a/include/swift/Demangling/DemangleNodes.def b/include/swift/Demangling/DemangleNodes.def
index df41580cf465c..d74f6a902ae89 100644
--- a/include/swift/Demangling/DemangleNodes.def
+++ b/include/swift/Demangling/DemangleNodes.def
@@ -75,6 +75,7 @@ NODE(DependentPseudogenericSignature)
 NODE(DependentProtocolConformanceRoot)
 NODE(DependentProtocolConformanceInherited)
 NODE(DependentProtocolConformanceAssociated)
+NODE(DependentProtocolConformanceOpaque)
 CONTEXT_NODE(Destructor)
 CONTEXT_NODE(DidSet)
 NODE(Directness)
@@ -137,6 +138,8 @@ NODE(ImplErasedIsolation)
 NODE(ImplSendingResult)
 NODE(ImplParameterResultDifferentiability)
 NODE(ImplParameterSending)
+NODE(ImplParameterIsolated)
+NODE(ImplParameterImplicitLeading)
 NODE(ImplFunctionAttribute)
 NODE(ImplFunctionConvention)
 NODE(ImplFunctionConventionName)
@@ -210,6 +213,7 @@ NODE(PrefixOperator)
 NODE(PrivateDeclName)
 NODE(PropertyDescriptor)
 CONTEXT_NODE(PropertyWrapperBackingInitializer)
+CONTEXT_NODE(PropertyWrappedFieldInitAccessor)
 CONTEXT_NODE(PropertyWrapperInitFromProjectedValue)
 CONTEXT_NODE(Protocol)
 CONTEXT_NODE(ProtocolSymbolicReference)
@@ -399,6 +403,7 @@ NODE(AsyncRemoved)
 // Added in Swift 5.TBD
 NODE(ObjectiveCProtocolSymbolicReference)
 
+NODE(OutlinedInitializeWithTakeNoValueWitness)
 NODE(OutlinedInitializeWithCopyNoValueWitness)
 NODE(OutlinedAssignWithTakeNoValueWitness)
 NODE(OutlinedAssignWithCopyNoValueWitness)
@@ -406,7 +411,7 @@ NODE(OutlinedDestroyNoValueWitness)
 
 NODE(DependentGenericInverseConformanceRequirement)
 
-// Added in Swift 6.TBD
+// Added in Swift 6.2
 NODE(Integer)
 NODE(NegativeInteger)
 NODE(DependentGenericParamValueMarker)
@@ -414,5 +419,9 @@ NODE(CoroFunctionPointer)
 NODE(DefaultOverride)
 NODE(ConstValue)
 
+// Added in Swift 6.TBD
+CONTEXT_NODE(BorrowAccessor)
+CONTEXT_NODE(MutateAccessor)
+
 #undef CONTEXT_NODE
 #undef NODE
diff --git a/include/swift/Demangling/Demangler.h b/include/swift/Demangling/Demangler.h
index f634e5a86181b..62f0298cf6e93 100644
--- a/include/swift/Demangling/Demangler.h
+++ b/include/swift/Demangling/Demangler.h
@@ -249,6 +249,12 @@ class NodeFactory {
   /// Creates a node of kind \p K with an \p Index payload.
   NodePointer createNode(Node::Kind K, Node::IndexType Index);
 
+  /// Creates a node of kind \p K with a \p RemoteAddress payload.
+  ///
+  /// These nodes are created and consumed by the reflection library.
+  NodePointer createNode(Node::Kind K, uint64_t RemoteAddress,
+                         uint8_t AddressSpace);
+
   /// Creates a node of kind \p K with a \p Text payload.
   ///
   /// The \p Text string must be already allocated with the Factory and therefore
@@ -570,6 +576,8 @@ class Demangler : public NodeFactory {
   NodePointer demangleImplParamConvention(Node::Kind ConvKind);
   NodePointer demangleImplResultConvention(Node::Kind ConvKind);
   NodePointer demangleImplParameterSending();
+  NodePointer demangleImplParameterIsolated();
+  NodePointer demangleImplParameterImplicitLeading();
   NodePointer demangleImplParameterResultDifferentiability();
   NodePointer demangleImplFunctionType();
   NodePointer demangleClangType();
@@ -596,6 +604,7 @@ class Demangler : public NodeFactory {
   NodePointer demangleDependentProtocolConformanceInherited();
   NodePointer popDependentAssociatedConformance();
   NodePointer demangleDependentProtocolConformanceAssociated();
+  NodePointer demangleDependentProtocolConformanceOpaque();
   NodePointer demangleThunkOrSpecialization();
   NodePointer demangleGenericSpecialization(Node::Kind SpecKind,
                                             NodePointer droppedArguments);
diff --git a/include/swift/Demangling/TypeDecoder.h b/include/swift/Demangling/TypeDecoder.h
index 724f6d01d019f..77bb3bc6ccd8e 100644
--- a/include/swift/Demangling/TypeDecoder.h
+++ b/include/swift/Demangling/TypeDecoder.h
@@ -118,6 +118,8 @@ enum class ImplParameterConvention {
 enum class ImplParameterInfoFlags : uint8_t {
   NotDifferentiable = 0x1,
   Sending = 0x2,
+  Isolated = 0x4,
+  ImplicitLeading = 0x8
 };
 
 using ImplParameterInfoOptions = OptionSet<ImplParameterInfoFlags>;
@@ -192,6 +194,22 @@ class ImplFunctionParam {
     return result;
   }
 
+  static OptionsType getIsolated() {
+    OptionsType result;
+
+    result |= ImplParameterInfoFlags::Isolated;
+
+    return result;
+  }
+
+  static OptionsType getImplicitLeading() {
+    OptionsType result;
+
+    result |= ImplParameterInfoFlags::ImplicitLeading;
+
+    return result;
+  }
+
   ImplFunctionParam(BuiltType type, ImplParameterConvention convention,
                     OptionsType options)
       : Type(type), Convention(convention), Options(options) {}
@@ -555,6 +573,43 @@ void decodeRequirement(
   }
 }
 
+/// Extract the protocol and requirement nodes from a shape symbol.
+static inline std::pair<NodePointer, NodePointer>
+decodeShape(NodePointer Node) {
+  if (!Node || Node->getKind() != Node::Kind::Global ||
+      Node->getNumChildren() != 1)
+    return {nullptr, nullptr};
+  Node = Node->getChild(0);
+  if (Node && (Node->getKind() == Node::Kind::Uniquable) &&
+      Node->getNumChildren() == 1)
+    Node = Node->getChild(0);
+  if (!Node || Node->getKind() != Node::Kind::ExtendedExistentialTypeShape ||
+      Node->getNumChildren() != 2)
+    return {nullptr, nullptr};
+  Node = Node->getChild(1);
+  if (!Node || Node->getKind() != Node::Kind::Type ||
+      Node->getNumChildren() != 1)
+    return {nullptr, nullptr};
+  Node = Node->getChild(0);
+  if (!Node || Node->getKind() != Node::Kind::ConstrainedExistential ||
+      Node->getNumChildren() != 2)
+    return {nullptr, nullptr};
+  NodePointer Requirements = Node->getChild(1);
+  if (!Requirements || Requirements->getKind() !=
+                           Node::Kind::ConstrainedExistentialRequirementList)
+    return {nullptr, nullptr};
+
+  Node = Node->getChild(0);
+  if (!Node || Node->getKind() != Node::Kind::Type ||
+      Node->getNumChildren() != 1)
+    return {nullptr, nullptr};
+  NodePointer Protocol = Node;
+  if (!Protocol)
+    return {nullptr, nullptr};
+
+  return {Protocol, Requirements};
+}
+
 #define MAKE_NODE_TYPE_ERROR(Node, Fmt, ...)                                   \
   TYPE_LOOKUP_ERROR_FMT("TypeDecoder.h:%u: Node kind %u \"%.*s\" - " Fmt,      \
                         __LINE__, (unsigned)Node->getKind(),                   \
@@ -1143,11 +1198,11 @@ class TypeDecoder {
             return MAKE_NODE_TYPE_ERROR0(child,
                                          "failed to decode function yields");
         } else if (child->getKind() == NodeKind::ImplResult) {
-          if (decodeImplFunctionParam(child, depth + 1, results))
+          if (decodeImplFunctionResult(child, depth + 1, results))
             return MAKE_NODE_TYPE_ERROR0(child,
                                          "failed to decode function results");
         } else if (child->getKind() == NodeKind::ImplErrorResult) {
-          if (decodeImplFunctionPart(child, depth + 1, errorResults))
+          if (decodeImplFunctionResult(child, depth + 1, errorResults))
             return MAKE_NODE_TYPE_ERROR0(child,
                                          "failed to decode function part");
         } else {
@@ -1638,40 +1693,70 @@ class TypeDecoder {
   }
 
   template <typename T>
-  bool decodeImplFunctionPart(Demangle::NodePointer node, unsigned depth,
-                              llvm::SmallVectorImpl<T> &results) {
+  bool decodeImplFunctionParam(Demangle::NodePointer node, unsigned depth,
+                               llvm::SmallVectorImpl<T> &results) {
     if (depth > TypeDecoder::MaxDepth)
       return true;
 
-    if (node->getNumChildren() != 2)
+    // Children: `convention, attrs, type`
+    // attrs: `differentiability?, sending?, isolated?, implicit_leading?`
+    if (node->getNumChildren() < 2)
       return true;
-    
-    if (node->getChild(0)->getKind() != Node::Kind::ImplConvention ||
-        node->getChild(1)->getKind() != Node::Kind::Type)
+
+    auto *conventionNode = node->getChild(0);
+    auto *typeNode = node->getLastChild();
+    if (conventionNode->getKind() != Node::Kind::ImplConvention ||
+        typeNode->getKind() != Node::Kind::Type)
       return true;
 
-    StringRef conventionString = node->getChild(0)->getText();
-    std::optional<typename T::ConventionType> convention =
-        T::getConventionFromString(conventionString);
+    StringRef conventionString = conventionNode->getText();
+    auto convention = T::getConventionFromString(conventionString);
     if (!convention)
       return true;
-    auto type = decodeMangledType(node->getChild(1), depth + 1);
-    if (type.isError())
+    auto result = decodeMangledType(typeNode, depth + 1);
+    if (result.isError())
       return true;
 
-    results.emplace_back(type.getType(), *convention);
+    typename T::OptionsType options;
+    for (unsigned i = 1; i < node->getNumChildren() - 1; ++i) {
+      auto child = node->getChild(i);
+      switch (child->getKind()) {
+      case Node::Kind::ImplParameterResultDifferentiability: {
+        auto optDiffOptions =
+            T::getDifferentiabilityFromString(child->getText());
+        if (!optDiffOptions)
+          return true;
+        options |= *optDiffOptions;
+        break;
+      }
+      case Node::Kind::ImplParameterSending:
+        options |= T::getSending();
+        break;
+      case Node::Kind::ImplParameterIsolated:
+        options |= T::getIsolated();
+        break;
+      case Node::Kind::ImplParameterImplicitLeading:
+        options |= T::getImplicitLeading();
+        break;
+      default:
+        return true;
+      }
+    }
+
+    results.emplace_back(result.getType(), *convention, options);
+
     return false;
   }
 
   template <typename T>
-  bool decodeImplFunctionParam(Demangle::NodePointer node, unsigned depth,
-                               llvm::SmallVectorImpl<T> &results) {
+  bool decodeImplFunctionResult(Demangle::NodePointer node, unsigned depth,
+                                llvm::SmallVectorImpl<T> &results) {
     if (depth > TypeDecoder::MaxDepth)
       return true;
 
-    // Children: `convention, differentiability?, sending?, type`
-    if (node->getNumChildren() != 2 && node->getNumChildren() != 3 &&
-        node->getNumChildren() != 4)
+    // Children: `convention, attrs, type`
+    // attrs: `differentiability?, sending?, isolated?, implicit_leading?`
+    if (node->getNumChildren() < 2)
       return true;
 
     auto *conventionNode = node->getChild(0);
@@ -1689,23 +1774,23 @@ class TypeDecoder {
       return true;
 
     typename T::OptionsType options;
-    if (node->getNumChildren() == 3 || node->getNumChildren() == 4) {
-      auto diffKindNode = node->getChild(1);
-      if (diffKindNode->getKind() !=
-          Node::Kind::ImplParameterResultDifferentiability)
-        return true;
-      auto optDiffOptions =
-          T::getDifferentiabilityFromString(diffKindNode->getText());
-      if (!optDiffOptions)
-        return true;
-      options |= *optDiffOptions;
-    }
-
-    if (node->getNumChildren() == 4) {
-      auto sendingKindNode = node->getChild(2);
-      if (sendingKindNode->getKind() != Node::Kind::ImplParameterSending)
+    for (unsigned i = 1; i < node->getNumChildren() - 1; ++i) {
+      auto child = node->getChild(i);
+      switch (child->getKind()) {
+      case Node::Kind::ImplParameterResultDifferentiability: {
+        auto optDiffOptions =
+            T::getDifferentiabilityFromString(child->getText());
+        if (!optDiffOptions)
+          return true;
+        options |= *optDiffOptions;
+        break;
+      }
+      case Node::Kind::ImplParameterSending:
+        options |= T::getSending();
+        break;
+      default:
         return true;
-      options |= T::getSending();
+      }
     }
 
     results.emplace_back(result.getType(), *convention, options);
diff --git a/include/swift/DependencyScan/DependencyScanImpl.h b/include/swift/DependencyScan/DependencyScanImpl.h
index c5507ea7c731d..13408e2c98bcd 100644
--- a/include/swift/DependencyScan/DependencyScanImpl.h
+++ b/include/swift/DependencyScan/DependencyScanImpl.h
@@ -43,7 +43,6 @@ struct swiftscan_dependency_info_s {
   /// "swiftInterface"
   /// "swiftSource"
   /// "swiftBinary"
-  /// "swiftPlaceholder"
   /// "clang""
   swiftscan_string_ref_t module_name;
 
@@ -63,6 +62,12 @@ struct swiftscan_dependency_info_s {
   /// The list of link libraries for this module.
   swiftscan_link_library_set_t *link_libraries;
 
+  /// The list of source import infos.
+  swiftscan_import_info_set_t *imports;
+
+  /// The list of source optional import infos.
+  swiftscan_import_info_set_t *optional_imports;
+
   /// Specific details of a particular kind of module.
   swiftscan_module_details_t details;
 };
@@ -74,10 +79,16 @@ struct swiftscan_link_library_info_s {
   bool forceLoad;
 };
 
+struct swiftscan_import_info_s {
+  swiftscan_string_ref_t import_identifier;
+  swiftscan_source_location_set_t *source_locations;
+  swiftscan_access_level_t access_level;
+};
+
 struct swiftscan_macro_dependency_s {
-  swiftscan_string_ref_t moduleName;
-  swiftscan_string_ref_t libraryPath;
-  swiftscan_string_ref_t executablePath;
+  swiftscan_string_ref_t module_name;
+  swiftscan_string_ref_t library_path;
+  swiftscan_string_ref_t executable_path;
 };
 
 /// Swift modules to be built from a module interface, may have a bridging
@@ -102,6 +113,9 @@ typedef struct {
   /// Clang module dependencies
   swiftscan_string_set_t *swift_overlay_module_dependencies;
 
+  /// Directly-imported in source module dependencies
+  swiftscan_string_set_t *source_import_module_dependencies;
+
   /// Options to the compile command required to build this module interface
   swiftscan_string_set_t *command_line;
 
@@ -180,19 +194,6 @@ typedef struct {
   swiftscan_string_ref_t user_module_version;
 } swiftscan_swift_binary_details_t;
 
-/// Swift placeholder modules carry additional details that specify their
-/// module doc path and source info paths.
-typedef struct {
-  /// The path to the pre-compiled binary module
-  swiftscan_string_ref_t compiled_module_path;
-
-  /// The path to the .swiftModuleDoc file.
-  swiftscan_string_ref_t module_doc_path;
-
-  /// The path to the .swiftSourceInfo file.
-  swiftscan_string_ref_t module_source_info_path;
-} swiftscan_swift_placeholder_details_t;
-
 /// Clang modules are built from a module map file.
 typedef struct {
   /// The path to the module map used to build this module.
@@ -219,7 +220,6 @@ struct swiftscan_module_details_s {
   union {
     swiftscan_swift_textual_details_t swift_textual_details;
     swiftscan_swift_binary_details_t swift_binary_details;
-    swiftscan_swift_placeholder_details_t swift_placeholder_details;
     swiftscan_clang_details_t clang_details;
   };
 };
diff --git a/include/swift/DependencyScan/DependencyScanningTool.h b/include/swift/DependencyScan/DependencyScanningTool.h
index 7129b1503c781..1544109083252 100644
--- a/include/swift/DependencyScan/DependencyScanningTool.h
+++ b/include/swift/DependencyScan/DependencyScanningTool.h
@@ -15,57 +15,94 @@
 
 #include "swift-c/DependencyScan/DependencyScan.h"
 #include "swift/Frontend/Frontend.h"
+#include "swift/AST/DiagnosticConsumer.h"
 #include "swift/AST/ModuleDependencies.h"
 #include "swift/DependencyScan/ScanDependencies.h"
 #include "swift/Frontend/PrintingDiagnosticConsumer.h"
+#include "swift/Frontend/SerializedDiagnosticConsumer.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/StringSaver.h"
 
 namespace swift {
 namespace dependencies {
 class DependencyScanningTool;
-class DependencyScanDiagnosticCollector;
+class DepScanInMemoryDiagnosticCollector;
 
-struct ScanQueryInstance {
+struct ScanQueryContext {
+  /// Primary CompilerInstance configured for this scanning action
   std::unique_ptr<CompilerInstance> ScanInstance;
-  std::shared_ptr<DependencyScanDiagnosticCollector> ScanDiagnostics;
+  /// An thread-safe diagnostic consumer which collects all emitted
+  /// diagnostics in the scan to be reporte via libSwiftScan API
+  std::unique_ptr<DepScanInMemoryDiagnosticCollector> InMemoryDiagnosticCollector;
+  /// A thread-safe serialized diagnostics consumer.
+  /// Note, although type-erased, this must be an instance of
+  /// 'ThreadSafeSerializedDiagnosticConsumer'
+  std::unique_ptr<DiagnosticConsumer> SerializedDiagnosticConsumer;
+
+  ScanQueryContext(
+      std::unique_ptr<CompilerInstance> ScanInstance,
+      std::unique_ptr<DepScanInMemoryDiagnosticCollector>
+          InMemoryDiagnosticCollector,
+      std::unique_ptr<DiagnosticConsumer> SerializedDiagnosticConsumer)
+      : ScanInstance(std::move(ScanInstance)),
+        InMemoryDiagnosticCollector(std::move(InMemoryDiagnosticCollector)),
+        SerializedDiagnosticConsumer(std::move(SerializedDiagnosticConsumer)) {}
+
+  ScanQueryContext(ScanQueryContext &&other)
+      : ScanInstance(std::move(other.ScanInstance)),
+        InMemoryDiagnosticCollector(
+            std::move(other.InMemoryDiagnosticCollector)),
+        SerializedDiagnosticConsumer(
+            std::move(other.SerializedDiagnosticConsumer)) {}
+
+  ~ScanQueryContext() {
+    if (SerializedDiagnosticConsumer)
+      SerializedDiagnosticConsumer->finishProcessing();
+  }
 };
 
-/// Diagnostic consumer that simply collects the diagnostics emitted so-far
-class DependencyScanDiagnosticCollector : public DiagnosticConsumer {
+/// Pure virtual Diagnostic consumer intended for collecting
+/// emitted diagnostics in a thread-safe fashion
+class ThreadSafeDiagnosticCollector : public DiagnosticConsumer {
 private:
+  llvm::sys::SmartMutex<true> DiagnosticConsumerStateLock;
+  void handleDiagnostic(SourceManager &SM, const DiagnosticInfo &Info) final;
+
+protected:
+  virtual void addDiagnostic(SourceManager &SM, const DiagnosticInfo &Info) = 0;
+
+public:
+  ThreadSafeDiagnosticCollector() {}
+  bool finishProcessing() final { return false; }
+};
+
+/// Diagnostic consumer that simply collects the diagnostics emitted so-far
+/// and uses a representation agnostic from any specific CompilerInstance state
+/// which may have been used to emit the diagnostic
+class DepScanInMemoryDiagnosticCollector
+    : public ThreadSafeDiagnosticCollector {
+public:
   struct ScannerDiagnosticInfo {
     std::string Message;
     llvm::SourceMgr::DiagKind Severity;
-    std::optional<ScannerImportStatementInfo::ImportDiagnosticLocationInfo> ImportLocation;
+    std::optional<ScannerImportStatementInfo::ImportDiagnosticLocationInfo>
+        ImportLocation;
   };
   std::vector<ScannerDiagnosticInfo> Diagnostics;
 
-  void handleDiagnostic(SourceManager &SM, const DiagnosticInfo &Info) override;
-
 protected:
-  virtual void addDiagnostic(SourceManager &SM, const DiagnosticInfo &Info);
+  void addDiagnostic(SourceManager &SM, const DiagnosticInfo &Info) override;
 
 public:
   friend DependencyScanningTool;
-  DependencyScanDiagnosticCollector() {}
+  DepScanInMemoryDiagnosticCollector() {}
   void reset() { Diagnostics.clear(); }
-  const std::vector<ScannerDiagnosticInfo> &getDiagnostics() const {
+  std::vector<ScannerDiagnosticInfo> getDiagnostics() const {
+    return Diagnostics;
+  }
+  const std::vector<ScannerDiagnosticInfo> &getDiagnosticsRef() const {
     return Diagnostics;
   }
-};
-
-/// Locking variant of the above diagnostic collector that guards accesses to
-/// its state with a lock.
-class LockingDependencyScanDiagnosticCollector
-    : public DependencyScanDiagnosticCollector {
-private:
-  void addDiagnostic(SourceManager &SM, const DiagnosticInfo &Info) override;
-  llvm::sys::SmartMutex<true> ScanningDiagnosticConsumerStateLock;
-
-public:
-  friend DependencyScanningTool;
-  LockingDependencyScanDiagnosticCollector() {}
 };
 
 /// Given a set of arguments to a print-target-info frontend tool query, produce the
@@ -80,14 +117,12 @@ class DependencyScanningTool {
   /// Construct a dependency scanning tool.
   DependencyScanningTool();
 
-  /// Collect the full module dependency graph for the input, ignoring any
-  /// placeholder modules.
+  /// Collect the full module dependency graph for the input.
   ///
   /// \returns a \c StringError with the diagnostic output if errors
   /// occurred, \c swiftscan_dependency_result_t otherwise.
   llvm::ErrorOr<swiftscan_dependency_graph_t>
   getDependencies(ArrayRef<const char *> Command,
-                  const llvm::StringSet<> &PlaceholderModules,
                   StringRef WorkingDirectory);
 
   /// Collect the set of imports for the input module
@@ -97,17 +132,12 @@ class DependencyScanningTool {
   llvm::ErrorOr<swiftscan_import_set_t>
   getImports(ArrayRef<const char *> Command, StringRef WorkingDirectory);
 
-  /// Query diagnostics consumed so far.
-  std::vector<DependencyScanDiagnosticCollector::ScannerDiagnosticInfo> getDiagnostics();
-  /// Discared the collection of diagnostics encountered so far.
-  void resetDiagnostics();
-
   /// Using the specified invocation command, instantiate a CompilerInstance
   /// that will be used for this scan.
-  llvm::ErrorOr<ScanQueryInstance>
-  initCompilerInstanceForScan(ArrayRef<const char *> Command,
-                              StringRef WorkingDirectory,
-                              std::shared_ptr<DependencyScanDiagnosticCollector> scannerDiagnosticsCollector);
+  llvm::ErrorOr<ScanQueryContext> createScanQueryContext(
+      ArrayRef<const char *> Command, StringRef WorkingDirectory,
+      std::vector<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+          &initializationDiagnostics);
 
 private:
   /// Shared cache of module dependencies, re-used by individual full-scan queries
@@ -116,14 +146,13 @@ class DependencyScanningTool {
 
   /// Shared state mutual-exclusivity lock
   llvm::sys::SmartMutex<true> DependencyScanningToolStateLock;
-
-  /// A shared consumer that accumulates encountered diagnostics.
-  LockingDependencyScanDiagnosticCollector CDC;
   llvm::BumpPtrAllocator Alloc;
   llvm::StringSaver Saver;
 };
 
-swiftscan_diagnostic_set_t *mapCollectedDiagnosticsForOutput(const DependencyScanDiagnosticCollector *diagnosticCollector);
+swiftscan_diagnostic_set_t *mapCollectedDiagnosticsForOutput(
+    ArrayRef<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+        diagnostics);
 
 } // end namespace dependencies
 } // end namespace swift
diff --git a/include/swift/DependencyScan/ModuleDependencyScanner.h b/include/swift/DependencyScan/ModuleDependencyScanner.h
index 6065ccc6d4998..df768db99374b 100644
--- a/include/swift/DependencyScan/ModuleDependencyScanner.h
+++ b/include/swift/DependencyScan/ModuleDependencyScanner.h
@@ -1,5 +1,4 @@
-//===--- ModuleDependencyScanner.h - Import Swift modules --------*- C++
-//-*-===//
+//===--- ModuleDependencyScanner.h - Import Swift modules ------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -15,7 +14,8 @@
 #include "swift/AST/Identifier.h"
 #include "swift/AST/ModuleDependencies.h"
 #include "swift/Frontend/ModuleInterfaceLoader.h"
-#include "swift/Serialization/SerializedModuleLoader.h"
+#include "swift/Serialization/ScanningLoaders.h"
+#include "clang/Tooling/DependencyScanning/DependencyScanningTool.h"
 #include "llvm/CAS/CASReference.h"
 #include "llvm/Support/ThreadPool.h"
 
@@ -25,6 +25,12 @@ class DependencyTracker;
 
 namespace swift {
 
+/// A callback to lookup module outputs for "-fmodule-file=", "-o" etc.
+using LookupModuleOutputCallback = llvm::function_ref<std::string(
+    const clang::tooling::dependencies::ModuleDeps &,
+    clang::tooling::dependencies::ModuleOutputKind)>;
+using RemapPathCallback = llvm::function_ref<std::string(StringRef)>;
+
 /// A dependency scanning worker which performs filesystem lookup
 /// of a named module dependency.
 class ModuleDependencyScanningWorker {
@@ -33,22 +39,66 @@ class ModuleDependencyScanningWorker {
       SwiftDependencyScanningService &globalScanningService,
       const CompilerInvocation &ScanCompilerInvocation,
       const SILOptions &SILOptions, ASTContext &ScanASTContext,
-      DependencyTracker &DependencyTracker, DiagnosticEngine &diags);
+      DependencyTracker &DependencyTracker,
+      std::shared_ptr<llvm::cas::ObjectStore> CAS,
+      std::shared_ptr<llvm::cas::ActionCache> ActionCache,
+      llvm::PrefixMapper *mapper, DiagnosticEngine &diags);
 
 private:
-  /// Retrieve the module dependencies for the Clang module with the given name.
-  ModuleDependencyVector scanFilesystemForClangModuleDependency(
-      Identifier moduleName, StringRef moduleOutputPath,
-      StringRef sdkModuleOutputPath,
+  /// Query dependency information for a named Clang module
+  ///
+  /// \param moduleName moduel identifier for the query
+  ///
+  /// \param lookupModuleCallback a callback to compute a client-specific
+  /// module-cache-relative output path for discovered Clang module dependencies.
+  ///
+  /// \param alreadySeenModules a set of module dependencies previously seen
+  /// by the scanner, as to avoid processing them all over again
+  ///
+  /// \returns Clang dependency scanner's \c TranslationUnitDeps result
+  std::optional<clang::tooling::dependencies::TranslationUnitDeps>
+  scanFilesystemForClangModuleDependency(
+      Identifier moduleName,
+      LookupModuleOutputCallback lookupModuleCallback,
+      const llvm::DenseSet<clang::tooling::dependencies::ModuleID>
+          &alreadySeenModules);
+
+  /// Query dependency information for header dependencies
+  /// of a binary Swift module.
+  ///
+  /// \param moduleID the name of the Swift module whose dependency
+  /// information will be augmented with information about the given
+  /// textual header inputs.
+  ///
+  /// \param headerPath optional path to the header to be scanned.
+  ///
+  /// \param sourceBuffer optional in-memory buffer of a header to be scanned.
+  ///
+  /// \param lookupModuleCallback a callback to compute a client-specific
+  /// module-cache-relative output path for discovered Clang module dependencies.
+  ///
+  /// \param alreadySeenModules a set of module dependencies previously seen
+  /// by the scanner, as to avoid processing them all over again
+  ///
+  /// \returns Clang dependency scanner's \c TranslationUnitDeps result
+  std::optional<clang::tooling::dependencies::TranslationUnitDeps>
+  scanHeaderDependenciesOfSwiftModule(
+      ModuleDependencyID moduleID, std::optional<StringRef> headerPath,
+      std::optional<llvm::MemoryBufferRef> sourceBuffer,
+      LookupModuleOutputCallback lookupModuleCallback,
       const llvm::DenseSet<clang::tooling::dependencies::ModuleID>
-          &alreadySeenModules,
-      llvm::PrefixMapper *prefixMapper);
+         &alreadySeenModules);
 
-  /// Retrieve the module dependencies for the Swift module with the given name.
-  ModuleDependencyVector scanFilesystemForSwiftModuleDependency(
-      Identifier moduleName, StringRef moduleOutputPath,
-      StringRef sdkModuleOutputPath, llvm::PrefixMapper *prefixMapper,
-      bool isTestableImport = false);
+  /// Query dependency information for a named Swift module
+  ///
+  /// \param moduleName moduel identifier for the query
+  ///
+  /// \param isTestableImport a boolean flag which indicates whether
+  /// this is an @testable dependency
+  ///
+  /// \returns a struct containing query results
+  SwiftModuleScannerQueryResult scanFilesystemForSwiftModuleDependency(
+      Identifier moduleName, bool isTestableImport = false);
 
   /// Store cache entry for include tree.
   llvm::Error
@@ -57,6 +107,8 @@ class ModuleDependencyScanningWorker {
 
   // Worker-specific instance of CompilerInvocation
   std::unique_ptr<CompilerInvocation> workerCompilerInvocation;
+  // Worker-specific diagnostic engine
+  std::unique_ptr<DiagnosticEngine> workerDiagnosticEngine;
   // Worker-specific instance of ASTContext
   std::unique_ptr<ASTContext> workerASTContext;
   // An AST delegate for interface scanning.
@@ -64,11 +116,89 @@ class ModuleDependencyScanningWorker {
   // The Clang scanner tool used by this worker.
   clang::tooling::dependencies::DependencyScanningTool clangScanningTool;
   // Swift and Clang module loaders acting as scanners.
-  std::unique_ptr<ModuleInterfaceLoader> swiftScannerModuleLoader;
-  std::unique_ptr<ClangImporter> clangScannerModuleLoader;
+  std::unique_ptr<SwiftModuleScanner> swiftModuleScannerLoader;
+
   // CAS instance.
   std::shared_ptr<llvm::cas::ObjectStore> CAS;
   std::shared_ptr<llvm::cas::ActionCache> ActionCache;
+
+  // Base command line invocation for clang scanner queries (both module and header)
+  std::vector<std::string> clangScanningBaseCommandLineArgs;
+  // Command line invocation for clang by-name module lookups
+  std::vector<std::string> clangScanningModuleCommandLineArgs;
+  // Clang-specific (-Xcc) command-line flags to include on
+  // Swift module compilation commands
+  std::vector<std::string> swiftModuleClangCC1CommandLineArgs;
+  // Working directory for clang module lookup queries
+  std::string clangScanningWorkingDirectoryPath;
+  // Restrict access to the parent scanner class.
+  friend class ModuleDependencyScanner;
+};
+
+// MARK: SwiftDependencyTracker
+/// Track swift dependency
+class SwiftDependencyTracker {
+public:
+  SwiftDependencyTracker(std::shared_ptr<llvm::cas::ObjectStore> CAS,
+                         llvm::PrefixMapper *Mapper,
+                         const CompilerInvocation &CI);
+  
+  void startTracking(bool includeCommonDeps = true);
+  void trackFile(const Twine &path);
+  llvm::Expected<llvm::cas::ObjectProxy> createTreeFromDependencies();
+  
+private:
+  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS;
+  std::shared_ptr<llvm::cas::ObjectStore> CAS;
+  llvm::PrefixMapper *Mapper;
+  
+  struct FileEntry {
+    llvm::cas::ObjectRef FileRef;
+    size_t Size;
+    
+    FileEntry(llvm::cas::ObjectRef FileRef, size_t Size)
+    : FileRef(FileRef), Size(Size) {}
+  };
+  llvm::StringMap<FileEntry> CommonFiles;
+  std::map<std::string, FileEntry> TrackedFiles;
+};
+
+class ModuleDependencyIssueReporter {
+private:
+  ModuleDependencyIssueReporter(DiagnosticEngine &Diagnostics)
+      : Diagnostics(Diagnostics) {}
+
+  /// Diagnose scanner failure and attempt to reconstruct the dependency
+  /// path from the main module to the missing dependency
+  void diagnoseModuleNotFoundFailure(
+      const ScannerImportStatementInfo &moduleImport,
+      const ModuleDependenciesCache &cache,
+      std::optional<ModuleDependencyID> dependencyOf,
+      std::optional<std::pair<ModuleDependencyID, std::string>>
+          resolvingSerializedSearchPath,
+      std::optional<
+          std::vector<SwiftModuleScannerQueryResult::IncompatibleCandidate>>
+          foundIncompatibleCandidates = std::nullopt);
+
+  /// Upon query failure, if incompatible binary module
+  /// candidates were found, emit a failure diagnostic
+  void diagnoseFailureOnOnlyIncompatibleCandidates(
+      const ScannerImportStatementInfo &moduleImport,
+      const std::vector<SwiftModuleScannerQueryResult::IncompatibleCandidate>
+          &candidates,
+      const ModuleDependenciesCache &cache,
+      std::optional<ModuleDependencyID> dependencyOf);
+
+  /// Emit warnings for each discovered binary Swift module
+  /// which was incompatible with the current compilation
+  /// when querying \c moduleName
+  void warnOnIncompatibleCandidates(
+      StringRef moduleName,
+      const std::vector<SwiftModuleScannerQueryResult::IncompatibleCandidate>
+          &candidates);
+
+  DiagnosticEngine &Diagnostics;
+  std::unordered_set<std::string> ReportedMissing;
   // Restrict access to the parent scanner class.
   friend class ModuleDependencyScanner;
 };
@@ -80,6 +210,8 @@ class ModuleDependencyScanner {
                           const SILOptions &SILOptions,
                           ASTContext &ScanASTContext,
                           DependencyTracker &DependencyTracker,
+                          std::shared_ptr<llvm::cas::ObjectStore> CAS,
+                          std::shared_ptr<llvm::cas::ActionCache> ActionCache,
                           DiagnosticEngine &diags, bool ParallelScan);
 
   /// Identify the scanner invocation's main module's dependencies
@@ -92,22 +224,36 @@ class ModuleDependencyScanner {
   performDependencyScan(ModuleDependencyID rootModuleID,
                         ModuleDependenciesCache &cache);
 
-  /// Query the module dependency info for the Clang module with the given name.
-  /// Explicit by-name lookups are useful for batch mode scanning.
-  std::optional<const ModuleDependencyInfo *>
-  getNamedClangModuleDependencyInfo(StringRef moduleName,
-                                    ModuleDependenciesCache &cache,
-                                    ModuleDependencyIDSetVector &discoveredClangModules);
-
-  /// Query the module dependency info for the Swift module with the given name.
-  /// Explicit by-name lookups are useful for batch mode scanning.
-  std::optional<const ModuleDependencyInfo *>
-  getNamedSwiftModuleDependencyInfo(StringRef moduleName,
-                                    ModuleDependenciesCache &cache);
-
   /// How many filesystem lookups were performed by the scanner
   unsigned getNumLookups() { return NumLookups; }
 
+  /// CAS Dependency Tracker.
+  std::optional<SwiftDependencyTracker>
+  createSwiftDependencyTracker(const CompilerInvocation &CI) {
+    if (!CAS)
+      return std::nullopt;
+
+    return SwiftDependencyTracker(CAS, PrefixMapper.get(), CI);
+  }
+
+  /// PrefixMapper for scanner.
+  bool hasPathMapping() const {
+    return PrefixMapper && !PrefixMapper->getMappings().empty();
+  }
+  llvm::PrefixMapper *getPrefixMapper() const { return PrefixMapper.get(); }
+  std::string remapPath(StringRef Path) const;
+
+  /// CAS options.
+  llvm::cas::ObjectStore &getCAS() const {
+    assert(CAS && "Expect CAS available");
+    return *CAS;
+  }
+
+  llvm::vfs::FileSystem &getSharedCachingFS() const {
+    assert(CacheFS && "Expect CacheFS available");
+    return *CacheFS;
+  }
+
 private:
   /// Main routine that computes imported module dependency transitive
   /// closure for the given module.
@@ -118,8 +264,8 @@ class ModuleDependencyScanner {
   /// 4. Swift overlay modules of all of the transitively imported Clang modules
   /// that have one
   ModuleDependencyIDSetVector
-  resolveImportedModuleDependencies(const ModuleDependencyID &rootModuleID,
-                                    ModuleDependenciesCache &cache);
+  resolveImportedModuleDependencies(
+      const ModuleDependencyID &rootModuleID, ModuleDependenciesCache &cache);
   void resolveSwiftModuleDependencies(
       const ModuleDependencyID &rootModuleID, ModuleDependenciesCache &cache,
       ModuleDependencyIDSetVector &discoveredSwiftModules);
@@ -156,28 +302,63 @@ class ModuleDependencyScanner {
       StringRef mainModuleName, ModuleDependenciesCache &cache,
       llvm::function_ref<void(ModuleDependencyID)> action);
 
-  /// Performance BridgingHeader Chaining.
+  /// Perform Bridging Header Chaining.
   llvm::Error
   performBridgingHeaderChaining(const ModuleDependencyID &rootModuleID,
                                 ModuleDependenciesCache &cache,
                                 ModuleDependencyIDSetVector &allModules);
 
+  /// Bridge Clang dependency scanner's dependency node
+  /// to the Swift scanner's `ModuleDependencyInfo`.
+  ModuleDependencyInfo
+  bridgeClangModuleDependency(
+      const clang::tooling::dependencies::ModuleDeps &clangDependency);
+
   /// Perform an operation utilizing one of the Scanning workers
   /// available to this scanner.
   template <typename Function, typename... Args>
   auto withDependencyScanningWorker(Function &&F, Args &&...ArgList);
 
+  /// Determine cache-relative output path for a given Clang module
+  std::string clangModuleOutputPathLookup(
+      const clang::tooling::dependencies::ModuleDeps &clangDep,
+      clang::tooling::dependencies::ModuleOutputKind moduleOutputKind) const;
+
+  /// Use the scanner's ASTContext to construct an `Identifier`
+  /// for a given module name.
   Identifier getModuleImportIdentifier(StringRef moduleName);
 
+  /// Assuming the \c `moduleImport` failed to resolve,
+  /// iterate over all binary Swift module dependencies with serialized
+  /// search paths and attempt to diagnose if the failed-to-resolve module
+  /// can be found on any of them. Returns the path containing
+  /// the module, if one is found.
+  std::optional<std::pair<ModuleDependencyID, std::string>>
+  attemptToFindResolvingSerializedSearchPath(
+      const ScannerImportStatementInfo &moduleImport,
+      const ModuleDependenciesCache &cache);
+
 private:
   const CompilerInvocation &ScanCompilerInvocation;
   ASTContext &ScanASTContext;
-  DiagnosticEngine &Diagnostics;
+  ModuleDependencyIssueReporter IssueReporter;
+
+  /// The location of where the explicitly-built modules will be output to
+  std::string ModuleOutputPath;
+  /// The location of where the explicitly-built SDK modules will be output to
+  std::string SDKModuleOutputPath;
 
   /// The available pool of workers for filesystem module search
   unsigned NumThreads;
   std::list<std::unique_ptr<ModuleDependencyScanningWorker>> Workers;
   llvm::DefaultThreadPool ScanningThreadPool;
+  // CAS instance.
+  std::shared_ptr<llvm::cas::ObjectStore> CAS;
+  std::shared_ptr<llvm::cas::ActionCache> ActionCache;
+  /// File prefix mapper.
+  std::unique_ptr<llvm::PrefixMapper> PrefixMapper;
+  /// CAS file system for loading file content.
+  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> CacheFS;
   /// Protect worker access.
   std::mutex WorkersLock;
   /// Count of filesystem queries performed
diff --git a/include/swift/DependencyScan/ScanDependencies.h b/include/swift/DependencyScan/ScanDependencies.h
index 9a2e275662d37..350680cafa2fb 100644
--- a/include/swift/DependencyScan/ScanDependencies.h
+++ b/include/swift/DependencyScan/ScanDependencies.h
@@ -22,6 +22,9 @@
 
 namespace llvm {
 class StringSaver;
+namespace cas {
+class ObjectStore;
+} // namespace cas
 namespace vfs {
 class FileSystem;
 } // namespace vfs
@@ -40,7 +43,7 @@ using ModuleDependencyIDSet =
 class SwiftDependencyScanningService;
 
 namespace dependencies {
-class DependencyScanDiagnosticCollector;
+struct ScanQueryContext;
 
 using CompilerArgInstanceCacheMap =
     llvm::StringMap<std::tuple<std::unique_ptr<CompilerInstance>,
@@ -58,15 +61,16 @@ bool prescanDependencies(CompilerInstance &instance);
 // MARK: Dependency scanning execution
 /// Scans the dependencies of the main module of \c instance.
 llvm::ErrorOr<swiftscan_dependency_graph_t>
-performModuleScan(CompilerInstance &instance,
-                  DependencyScanDiagnosticCollector *diagnostics,
-                  ModuleDependenciesCache &cache);
+performModuleScan(SwiftDependencyScanningService &service,
+                  ModuleDependenciesCache &cache,
+                  ScanQueryContext &queryContext);
 
 /// Scans the main module of \c instance for all direct module imports
 llvm::ErrorOr<swiftscan_import_set_t>
-performModulePrescan(CompilerInstance &instance,
-                     DependencyScanDiagnosticCollector *diagnostics,
-                     ModuleDependenciesCache &cache);
+performModulePrescan(SwiftDependencyScanningService &service,
+                     ModuleDependenciesCache &cache,
+                     ScanQueryContext &queryContext);
+
 
 namespace incremental {
 /// For the given module dependency graph captured in the 'cache',
@@ -76,6 +80,7 @@ namespace incremental {
 /// be re-scanned.
 void validateInterModuleDependenciesCache(
     const ModuleDependencyID &rootModuleID, ModuleDependenciesCache &cache,
+    std::shared_ptr<llvm::cas::ObjectStore> cas,
     const llvm::sys::TimePoint<> &cacheTimeStamp, llvm::vfs::FileSystem &fs,
     DiagnosticEngine &diags, bool emitRemarks = false);
 
@@ -85,6 +90,7 @@ void validateInterModuleDependenciesCache(
 /// module.
 void outOfDateModuleScan(const ModuleDependencyID &sourceModuleID,
                          const ModuleDependenciesCache &cache,
+                         std::shared_ptr<llvm::cas::ObjectStore> cas,
                          const llvm::sys::TimePoint<> &cacheTimeStamp,
                          llvm::vfs::FileSystem &fs, DiagnosticEngine &diags,
                          bool emitRemarks, ModuleDependencyIDSet &visited,
@@ -94,6 +100,7 @@ void outOfDateModuleScan(const ModuleDependencyID &sourceModuleID,
 /// are older than the cache serialization time.
 bool verifyModuleDependencyUpToDate(
     const ModuleDependencyID &moduleID, const ModuleDependenciesCache &cache,
+    std::shared_ptr<llvm::cas::ObjectStore> cas,
     const llvm::sys::TimePoint<> &cacheTimeStamp, llvm::vfs::FileSystem &fs,
     DiagnosticEngine &diags, bool emitRemarks);
 } // end namespace incremental
diff --git a/include/swift/DependencyScan/SerializedModuleDependencyCacheFormat.h b/include/swift/DependencyScan/SerializedModuleDependencyCacheFormat.h
index fddb8bdd721dc..e1a324ef1b5a8 100644
--- a/include/swift/DependencyScan/SerializedModuleDependencyCacheFormat.h
+++ b/include/swift/DependencyScan/SerializedModuleDependencyCacheFormat.h
@@ -39,9 +39,9 @@ using llvm::BCVBR;
 
 /// Every .moddepcache file begins with these 4 bytes, for easy identification.
 const unsigned char MODULE_DEPENDENCY_CACHE_FORMAT_SIGNATURE[] = {'I', 'M', 'D','C'};
-const unsigned MODULE_DEPENDENCY_CACHE_FORMAT_VERSION_MAJOR = 9;
+const unsigned MODULE_DEPENDENCY_CACHE_FORMAT_VERSION_MAJOR = 10;
 /// Increment this on every change.
-const unsigned MODULE_DEPENDENCY_CACHE_FORMAT_VERSION_MINOR = 1;
+const unsigned MODULE_DEPENDENCY_CACHE_FORMAT_VERSION_MINOR = 4;
 
 /// Various identifiers in this format will rely on having their strings mapped
 /// using this ID.
@@ -56,6 +56,8 @@ using IsFrameworkField = BCFixed<1>;
 using IsSystemField = BCFixed<1>;
 /// A bit that indicates whether or not a module is that of a static archive
 using IsStaticField = BCFixed<1>;
+/// A bit that indicates whether or not a module is built with C++ interop
+using IsBuiltWithCxxInteropField = BCFixed<1>;
 /// A bit that indicates whether or not a link library is a force-load one
 using IsForceLoadField = BCFixed<1>;
 /// A bit that indicates whether or not an import statement is optional
@@ -67,6 +69,9 @@ using IsExportedImport = BCFixed<1>;
 using LineNumberField = BCFixed<32>;
 using ColumnNumberField = BCFixed<32>;
 
+/// Access level of an import
+using AccessLevelField = BCFixed<8>;
+
 /// Arrays of various identifiers, distinguished for readability
 using IdentifierIDArryField = llvm::BCArray<IdentifierIDField>;
 using ModuleIDArryField = llvm::BCArray<IdentifierIDField>;
@@ -78,9 +83,9 @@ using ModuleCacheKeyIDField = IdentifierIDField;
 using ImportArrayIDField = IdentifierIDField;
 using LinkLibrariesArrayIDField = IdentifierIDField;
 using MacroDependenciesArrayIDField = IdentifierIDField;
+using SearchPathArrayIDField = IdentifierIDField;
 using FlagIDArrayIDField = IdentifierIDField;
 using DependencyIDArrayIDField = IdentifierIDField;
-using AuxiliaryFilesArrayIDField = IdentifierIDField;
 using SourceLocationIDArrayIDField = IdentifierIDField;
 
 /// The ID of the top-level block containing the dependency graph
@@ -102,12 +107,13 @@ enum {
   LINK_LIBRARY_ARRAY_NODE,
   MACRO_DEPENDENCY_NODE,
   MACRO_DEPENDENCY_ARRAY_NODE,
+  SEARCH_PATH_NODE,
+  SEARCH_PATH_ARRAY_NODE,
   IMPORT_STATEMENT_NODE,
   IMPORT_STATEMENT_ARRAY_NODE,
   OPTIONAL_IMPORT_STATEMENT_ARRAY_NODE,
   SWIFT_INTERFACE_MODULE_DETAILS_NODE,
   SWIFT_SOURCE_MODULE_DETAILS_NODE,
-  SWIFT_PLACEHOLDER_MODULE_DETAILS_NODE,
   SWIFT_BINARY_MODULE_DETAILS_NODE,
   CLANG_MODULE_DETAILS_NODE,
   IDENTIFIER_NODE,
@@ -170,6 +176,17 @@ using MacroDependencyLayout =
 using MacroDependencyArrayLayout =
     BCRecordLayout<MACRO_DEPENDENCY_ARRAY_NODE, IdentifierIDArryField>;
 
+// A record for a serialized search pathof a given dependency
+// node (Swift binary module dependency only).
+using SearchPathLayout =
+    BCRecordLayout<SEARCH_PATH_NODE,             // ID
+                   IdentifierIDField,            // path
+                   IsFrameworkField,             // isFramework
+                   IsSystemField                 // isSystem
+                   >;
+using SearchPathArrayLayout =
+    BCRecordLayout<SEARCH_PATH_ARRAY_NODE, IdentifierIDArryField>;
+
 // A record capturing information about a given 'import' statement
 // captured in a dependency node, including its source location.
 using ImportStatementLayout =
@@ -179,7 +196,8 @@ using ImportStatementLayout =
                    LineNumberField,              // lineNumber
                    ColumnNumberField,            // columnNumber
                    IsOptionalImport,             // isOptional
-                   IsExportedImport              // isExported
+                   IsExportedImport,             // isExported
+                   AccessLevelField              // accessLevel
                    >;
 using ImportStatementArrayLayout =
     BCRecordLayout<IMPORT_STATEMENT_ARRAY_NODE, IdentifierIDArryField>;
@@ -191,7 +209,6 @@ using OptionalImportStatementArrayLayout =
 // - SwiftInterfaceModuleDetails
 // - SwiftSourceModuleDetails
 // - SwiftBinaryModuleDetails
-// - SwiftPlaceholderModuleDetails
 // - ClangModuleDetails
 using ModuleInfoLayout =
     BCRecordLayout<MODULE_NODE,                    // ID
@@ -204,8 +221,7 @@ using ModuleInfoLayout =
                    DependencyIDArrayIDField,       // importedClangModules
                    DependencyIDArrayIDField,       // crossImportOverlayModules
                    DependencyIDArrayIDField,       // swiftOverlayDependencies
-                   ModuleCacheKeyIDField,          // moduleCacheKey
-                   AuxiliaryFilesArrayIDField      // auxiliaryFiles
+                   ModuleCacheKeyIDField           // moduleCacheKey
                    >;
 
 using SwiftInterfaceModuleDetailsLayout =
@@ -250,19 +266,14 @@ using SwiftBinaryModuleDetailsLayout =
                    FileIDField,                      // definingInterfacePath
                    IdentifierIDField,                // headerModuleDependencies
                    FileIDArrayIDField,               // headerSourceFiles
+                   SearchPathArrayIDField,           // serializedSearchPaths
                    IsFrameworkField,                 // isFramework
                    IsStaticField,                    // isStatic
+                   IsBuiltWithCxxInteropField,       // IsBuiltWithCxxInterop
                    IdentifierIDField,                // moduleCacheKey
                    IdentifierIDField                 // UserModuleVersion
                    >;
 
-using SwiftPlaceholderModuleDetailsLayout =
-    BCRecordLayout<SWIFT_PLACEHOLDER_MODULE_DETAILS_NODE, // ID
-                   FileIDField,                           // compiledModulePath
-                   FileIDField,                           // moduleDocPath
-                   FileIDField                            // moduleSourceInfoPath
-                   >;
-
 using ClangModuleDetailsLayout =
     BCRecordLayout<CLANG_MODULE_DETAILS_NODE, // ID
                    FileIDField,               // pcmOutputPath
diff --git a/include/swift/Driver/Action.h b/include/swift/Driver/Action.h
index 16795530100ac..4fd4350136f68 100644
--- a/include/swift/Driver/Action.h
+++ b/include/swift/Driver/Action.h
@@ -134,7 +134,7 @@ class CompileJobAction : public JobAction {
 
 public:
   CompileJobAction(file_types::ID OutputType)
-      : JobAction(Action::Kind::CompileJob, std::nullopt, OutputType) {}
+      : JobAction(Action::Kind::CompileJob, {}, OutputType) {}
   CompileJobAction(Action *Input, file_types::ID OutputType)
       : JobAction(Action::Kind::CompileJob, Input, OutputType) {}
 
@@ -169,8 +169,7 @@ class InterpretJobAction : public JobAction {
 
 public:
   explicit InterpretJobAction()
-      : JobAction(Action::Kind::InterpretJob, std::nullopt,
-                  file_types::TY_Nothing) {}
+      : JobAction(Action::Kind::InterpretJob, {}, file_types::TY_Nothing) {}
 
   static bool classof(const Action *A) {
     return A->getKind() == Action::Kind::InterpretJob;
@@ -209,7 +208,7 @@ class REPLJobAction : public JobAction {
   Mode RequestedMode;
 public:
   REPLJobAction(Mode mode)
-      : JobAction(Action::Kind::REPLJob, std::nullopt, file_types::TY_Nothing),
+      : JobAction(Action::Kind::REPLJob, {}, file_types::TY_Nothing),
         RequestedMode(mode) {}
 
   Mode getRequestedMode() const { return RequestedMode; }
diff --git a/include/swift/Driver/Compilation.h b/include/swift/Driver/Compilation.h
index 8d73ade0b824c..d482681ab4399 100644
--- a/include/swift/Driver/Compilation.h
+++ b/include/swift/Driver/Compilation.h
@@ -108,11 +108,11 @@ class Compilation {
   DiagnosticEngine &Diags;
 
   /// The ToolChain this Compilation was built with, that it may reuse to build
-  /// subsequent BatchJobs.
+  /// subsequent Jobs.
   const ToolChain &TheToolChain;
 
   /// The OutputInfo, which the Compilation stores a copy of upon
-  /// construction, and which it may use to build subsequent batch
+  /// construction, and which it may use to build subsequent
   /// jobs itself.
   OutputInfo TheOutputInfo;
 
@@ -167,22 +167,6 @@ class Compilation {
   /// even if they returned an error status.
   bool ContinueBuildingAfterErrors = false;
 
-  /// Indicates whether groups of parallel frontend jobs should be merged
-  /// together and run in composite "batch jobs" when possible, to reduce
-  /// redundant work.
-  const bool EnableBatchMode;
-
-  /// Provides a randomization seed to batch-mode partitioning, for debugging.
-  const unsigned BatchSeed;
-
-  /// Overrides parallelism level and \c BatchSizeLimit, sets exact
-  /// count of batches, if in batch-mode.
-  const std::optional<unsigned> BatchCount;
-
-  /// Overrides maximum batch size, if in batch-mode and not overridden
-  /// by \c BatchCount.
-  const std::optional<unsigned> BatchSizeLimit;
-
   /// True if temporary files should not be deleted.
   const bool SaveTemps;
 
@@ -244,10 +228,6 @@ class Compilation {
               std::unique_ptr<llvm::opt::DerivedArgList> TranslatedArgs,
               InputFileList InputsWithTypes,
               size_t FilelistThreshold,
-              bool EnableBatchMode = false,
-              unsigned BatchSeed = 0,
-              std::optional<unsigned> BatchCount = std::nullopt,
-              std::optional<unsigned> BatchSizeLimit = std::nullopt,
               bool SaveTemps = false,
               bool ShowDriverTimeCompilation = false,
               std::unique_ptr<UnifiedStatsReporter> Stats = nullptr,
@@ -302,10 +282,6 @@ class Compilation {
     return DerivedOutputFileMap;
   }
 
-  bool getBatchModeEnabled() const {
-    return EnableBatchMode;
-  }
-
   bool getContinueBuildingAfterErrors() const {
     return ContinueBuildingAfterErrors;
   }
@@ -352,14 +328,6 @@ class Compilation {
     return Level;
   }
 
-  unsigned getBatchSeed() const {
-    return BatchSeed;
-  }
-
-  std::optional<unsigned> getBatchCount() const { return BatchCount; }
-
-  std::optional<unsigned> getBatchSizeLimit() const { return BatchSizeLimit; }
-
   /// Requests the path to a file containing all input source files. This can
   /// be shared across jobs.
   ///
@@ -399,7 +367,7 @@ class Compilation {
   /// Unfortunately the success or failure of a Swift compilation is currently
   /// sensitive to the order in which files are processed, at least in terms of
   /// the order of processing extensions (and likely other ways we haven't
-  /// discovered yet). So long as this is true, we need to make sure any batch
+  /// discovered yet). So long as this is true, we need to make sure any
   /// job we build names its inputs in an order that's a subsequence of the
   /// sequence of inputs the driver was initially invoked with.
   ///
diff --git a/include/swift/Driver/Driver.h b/include/swift/Driver/Driver.h
index 5e506712e2335..2bc75f6cfa209 100644
--- a/include/swift/Driver/Driver.h
+++ b/include/swift/Driver/Driver.h
@@ -67,19 +67,6 @@ class OutputInfo {
     /// A compilation using a single frontend invocation without -primary-file.
     SingleCompile,
 
-    /// A single process that batches together multiple StandardCompile Jobs.
-    ///
-    /// Note: this is a transient value to use _only_ for the individual
-    /// BatchJobs that are the temporary containers for multiple StandardCompile
-    /// Jobs built by ToolChain::constructBatchJob.
-    ///
-    /// In particular, the driver treats a batch-mode-enabled Compilation as
-    /// having OutputInfo::CompilerMode == StandardCompile, with the
-    /// Compilation::BatchModeEnabled flag set to true, _not_ as a
-    /// BatchModeCompile Compilation. The top-level OutputInfo::CompilerMode for
-    /// a Compilation should never be BatchModeCompile.
-    BatchModeCompile,
-
     /// Invoke the REPL
     REPL,
 
@@ -171,7 +158,7 @@ class Driver {
   /// allowable OutputInfo::Mode values.
   enum class DriverKind {
     Interactive,     // swift
-    Batch,           // swiftc
+    Standard,        // swiftc
     SILOpt,          // sil-opt
     SILFuncExtractor,// sil-func-extractor
     SILNM,           // sil-nm
@@ -313,14 +300,12 @@ class Driver {
   ///
   /// \param TC The current tool chain.
   /// \param Args The input arguments.
-  /// \param BatchMode Whether the driver has been explicitly or implicitly
-  /// instructed to use batch mode.
   /// \param Inputs The inputs to the driver.
   /// \param[out] OI The OutputInfo in which to store the resulting output
   /// information.
   void buildOutputInfo(const ToolChain &TC,
                        const llvm::opt::DerivedArgList &Args,
-                       const bool BatchMode, const InputFileList &Inputs,
+                       const InputFileList &Inputs,
                        OutputInfo &OI) const;
 
   /// Construct the list of Actions to perform for the given arguments,
@@ -472,11 +457,8 @@ class Driver {
   /// there is an actual conflict.
   /// \param Args The input arguments.
   /// \param Inputs The inputs to the driver.
-  /// \param BatchModeOut An out-parameter flag that indicates whether to
-  /// batch the jobs of the resulting \c Mode::StandardCompile compilation.
   OutputInfo::Mode computeCompilerMode(const llvm::opt::DerivedArgList &Args,
-                                       const InputFileList &Inputs,
-                                       bool &BatchModeOut) const;
+                                       const InputFileList &Inputs) const;
 };
 
 } // end namespace driver
diff --git a/include/swift/Driver/Job.h b/include/swift/Driver/Job.h
index 3a2c28516732f..4c69181e1a414 100644
--- a/include/swift/Driver/Job.h
+++ b/include/swift/Driver/Job.h
@@ -389,8 +389,7 @@ class Job {
                                       StringRef Terminator = "\n") const;
 
   /// Call the provided Callback with any Jobs (and their possibly-quasi-PIDs)
-  /// contained within this Job; if this job is not a BatchJob, just pass \c
-  /// this and the provided \p OSPid back to the Callback.
+  /// contained within this Job;
   virtual void forEachContainedJobAndPID(
       llvm::sys::procid_t OSPid,
       llvm::function_ref<void(const Job *, Job::PID)> Callback) const {
@@ -411,51 +410,6 @@ class Job {
   StringRef getFirstSwiftPrimaryInput() const;
 };
 
-/// A BatchJob comprises a _set_ of jobs, each of which is sufficiently similar
-/// to the others that the whole set can be combined into a single subprocess
-/// (and thus run potentially more-efficiently than running each Job in the set
-/// individually).
-///
-/// Not all Jobs can be combined into a BatchJob: at present, only those Jobs
-/// that come from CompileJobActions, and which otherwise have the exact same
-/// input file list and arguments as one another, aside from their primary-file.
-/// See ToolChain::jobsAreBatchCombinable for details.
-
-class BatchJob : public Job {
-
-  /// The set of constituents making up the batch.
-  const SmallVector<const Job *, 4> CombinedJobs;
-
-  /// A negative number to use as the base value for assigning quasi-PID to Jobs
-  /// in the \c CombinedJobs array. Quasi-PIDs count _down_ from this value.
-  const Job::PID QuasiPIDBase;
-
-public:
-  BatchJob(const JobAction &Source, SmallVectorImpl<const Job *> &&Inputs,
-           std::unique_ptr<CommandOutput> Output, const char *Executable,
-           llvm::opt::ArgStringList Arguments,
-           EnvironmentVector ExtraEnvironment, std::vector<FilelistInfo> Infos,
-           ArrayRef<const Job *> Combined, Job::PID &NextQuasiPID,
-           std::optional<ResponseFileInfo> ResponseFile = std::nullopt);
-
-  ArrayRef<const Job*> getCombinedJobs() const {
-    return CombinedJobs;
-  }
-
-  /// Call the provided callback for each Job in the batch, passing the
-  /// corresponding quasi-PID with each Job.
-  void forEachContainedJobAndPID(
-      llvm::sys::procid_t OSPid,
-      llvm::function_ref<void(const Job *, Job::PID)> Callback) const override {
-    Job::PID QPid = QuasiPIDBase;
-    assert(QPid < 0);
-    for (auto const *J : CombinedJobs) {
-      assert(QPid != std::numeric_limits<Job::PID>::min());
-      Callback(J, QPid--);
-    }
-  }
-};
-
 } // end namespace driver
 } // end namespace swift
 
diff --git a/include/swift/Driver/ToolChain.h b/include/swift/Driver/ToolChain.h
index d438980d9a18e..415b608dc6171 100644
--- a/include/swift/Driver/ToolChain.h
+++ b/include/swift/Driver/ToolChain.h
@@ -98,7 +98,7 @@ class ToolChain {
     bool shouldUseSupplementaryOutputFileMapInFrontendInvocation() const;
 
     /// Reify the existing behavior that SingleCompile compile actions do not
-    /// filter, but batch-mode and single-file compilations do. Some clients are
+    /// filter, single-file compilations do. Some clients are
     /// relying on this (i.e., they pass inputs that don't have ".swift" as an
     /// extension.) It would be nice to eliminate this distinction someday.
     bool shouldFilterFrontendInputsByType() const;
@@ -281,33 +281,6 @@ class ToolChain {
                                     std::unique_ptr<CommandOutput> output,
                                     const OutputInfo &OI) const;
 
-  /// Return true iff the input \c Job \p A is an acceptable candidate for
-  /// batching together into a BatchJob, via a call to \c
-  /// constructBatchJob. This is true when the \c Job is a built from a \c
-  /// CompileJobAction in a \c Compilation \p C running in \c
-  /// OutputInfo::Mode::StandardCompile output mode, with a single \c TY_Swift
-  /// \c InputAction.
-  bool jobIsBatchable(const Compilation &C, const Job *A) const;
-
-  /// Equivalence relation that holds iff the two input Jobs \p A and \p B are
-  /// acceptable candidates for combining together into a \c BatchJob, via a
-  /// call to \c constructBatchJob. This is true when each job independently
-  /// satisfies \c jobIsBatchable, and the two jobs have identical executables,
-  /// output types and environments (i.e. they are identical aside from their
-  /// inputs).
-  bool jobsAreBatchCombinable(const Compilation &C, const Job *A,
-                              const Job *B) const;
-
-  /// Construct a \c BatchJob that subsumes the work of a set of Jobs. Any pair
-  /// of elements in \p Jobs are assumed to satisfy the equivalence relation \c
-  /// jobsAreBatchCombinable, i.e. they should all be "the same" job in in all
-  /// ways other than their choices of inputs. The provided \p NextQuasiPID
-  /// should be a negative number that persists between calls; this method will
-  /// decrement it to assign quasi-PIDs to each of the \p Jobs passed.
-  std::unique_ptr<Job> constructBatchJob(ArrayRef<const Job *> Jobs,
-                                         int64_t &NextQuasiPID,
-                                         Compilation &C) const;
-
   /// Return the default language type to use for the given extension.
   /// If the extension is empty or is otherwise not recognized, return
   /// the invalid type \c TY_INVALID.
diff --git a/include/swift/Frontend/CachingUtils.h b/include/swift/Frontend/CachingUtils.h
index e478c22daf56c..d676ccbcaa4e6 100644
--- a/include/swift/Frontend/CachingUtils.h
+++ b/include/swift/Frontend/CachingUtils.h
@@ -70,9 +70,9 @@ std::unique_ptr<llvm::MemoryBuffer> loadCachedCompileResultFromCacheKey(
     llvm::StringRef Filename = "");
 
 llvm::Expected<llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>>
-createCASFileSystem(llvm::cas::ObjectStore &CAS, ArrayRef<std::string> FSRoots,
-                    ArrayRef<std::string> IncludeTreeRoots,
-                    ArrayRef<std::string> IncludeTreeFileList);
+createCASFileSystem(llvm::cas::ObjectStore &CAS,
+                    const std::string &IncludeTreeRoot,
+                    const std::string &IncludeTreeFileList);
 
 std::vector<std::string> remapPathsFromCommandLine(
     ArrayRef<std::string> Args,
diff --git a/include/swift/Frontend/CompileJobCacheKey.h b/include/swift/Frontend/CompileJobCacheKey.h
index f32208f3a5511..fdc1090604c17 100644
--- a/include/swift/Frontend/CompileJobCacheKey.h
+++ b/include/swift/Frontend/CompileJobCacheKey.h
@@ -51,6 +51,11 @@ llvm::Error printCompileJobCacheKey(llvm::cas::ObjectStore &CAS,
                                     llvm::cas::ObjectRef Key,
                                     llvm::raw_ostream &os);
 
+/// Iterating through command-line options in cache key.
+llvm::Error iterateCommandLine(llvm::cas::ObjectStore &CAS,
+                               llvm::cas::ObjectRef Key,
+                               std::function<llvm::Error(StringRef)> Callback);
+
 } // namespace swift
 
 #endif
diff --git a/include/swift/Frontend/DiagnosticVerifier.h b/include/swift/Frontend/DiagnosticVerifier.h
index 5eb293f793137..8cd5ad1a03d0d 100644
--- a/include/swift/Frontend/DiagnosticVerifier.h
+++ b/include/swift/Frontend/DiagnosticVerifier.h
@@ -18,10 +18,15 @@
 #ifndef SWIFT_FRONTEND_DIAGNOSTIC_VERIFIER_H
 #define SWIFT_FRONTEND_DIAGNOSTIC_VERIFIER_H
 
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallString.h"
 #include "swift/AST/DiagnosticConsumer.h"
 #include "swift/Basic/LLVM.h"
 
+namespace {
+struct ExpectedDiagnosticInfo;
+}
+
 namespace swift {
 class DependencyTracker;
 class FileUnit;
@@ -94,6 +99,7 @@ class DiagnosticVerifier : public DiagnosticConsumer {
   ArrayRef<std::string> AdditionalFilePaths;
   bool AutoApplyFixes;
   bool IgnoreUnknown;
+  bool IgnoreUnrelated;
   bool UseColor;
   ArrayRef<std::string> AdditionalExpectedPrefixes;
 
@@ -101,11 +107,11 @@ class DiagnosticVerifier : public DiagnosticConsumer {
   explicit DiagnosticVerifier(SourceManager &SM, ArrayRef<unsigned> BufferIDs,
                               ArrayRef<std::string> AdditionalFilePaths,
                               bool AutoApplyFixes, bool IgnoreUnknown,
-                              bool UseColor,
+                              bool IgnoreUnrelated, bool UseColor,
                               ArrayRef<std::string> AdditionalExpectedPrefixes)
       : SM(SM), BufferIDs(BufferIDs), AdditionalFilePaths(AdditionalFilePaths),
         AutoApplyFixes(AutoApplyFixes), IgnoreUnknown(IgnoreUnknown),
-        UseColor(UseColor),
+        IgnoreUnrelated(IgnoreUnrelated), UseColor(UseColor),
         AdditionalExpectedPrefixes(AdditionalExpectedPrefixes) {}
 
   virtual void handleDiagnostic(SourceManager &SM,
@@ -126,13 +132,33 @@ class DiagnosticVerifier : public DiagnosticConsumer {
 
   void printDiagnostic(const llvm::SMDiagnostic &Diag) const;
 
+  /// Check whether there were any diagnostics in files without expected
+  /// diagnostics
+  bool verifyUnrelated(
+      std::vector<CapturedDiagnosticInfo> &CapturedDiagnostics) const;
+
   bool
   verifyUnknown(std::vector<CapturedDiagnosticInfo> &CapturedDiagnostics) const;
 
+  std::vector<llvm::SMDiagnostic> Errors;
+
   /// verifyFile - After the file has been processed, check to see if we
   /// got all of the expected diagnostics and check to see if there were any
   /// unexpected ones.
   Result verifyFile(unsigned BufferID);
+  unsigned parseExpectedDiagInfo(unsigned BufferID, StringRef MatchStart,
+                                 unsigned &PrevExpectedContinuationLine,
+                                 ExpectedDiagnosticInfo &Expected);
+  void
+  verifyDiagnostics(std::vector<ExpectedDiagnosticInfo> &ExpectedDiagnostics,
+                    unsigned BufferID);
+  void verifyRemaining(std::vector<ExpectedDiagnosticInfo> &ExpectedDiagnostics,
+                       const char *FileStart);
+  void addError(const char *Loc, const Twine &message,
+                ArrayRef<llvm::SMFixIt> FixIts = {});
+
+  std::optional<LineColumnRange>
+  parseExpectedFixItRange(StringRef &Str, unsigned DiagnosticLineNo);
 
   bool checkForFixIt(const std::vector<ExpectedFixIt> &ExpectedAlts,
                      const CapturedDiagnosticInfo &D, unsigned BufferID) const;
@@ -141,6 +167,8 @@ class DiagnosticVerifier : public DiagnosticConsumer {
   std::string renderFixits(ArrayRef<CapturedFixItInfo> ActualFixIts,
                            unsigned BufferID, unsigned DiagnosticLineNo) const;
 
+  llvm::DenseMap<SourceLoc, unsigned> Expansions;
+
   void printRemainingDiagnostics() const;
 };
 
diff --git a/include/swift/Frontend/Frontend.h b/include/swift/Frontend/Frontend.h
index 55d984a53db8a..9459134f6b8f5 100644
--- a/include/swift/Frontend/Frontend.h
+++ b/include/swift/Frontend/Frontend.h
@@ -176,7 +176,8 @@ class CompilerInvocation {
   }
 
   bool requiresCAS() const {
-    return CASOpts.EnableCaching || IRGenOpts.UseCASBackend;
+    return CASOpts.EnableCaching || IRGenOpts.UseCASBackend ||
+           CASOpts.ImportModuleFromCAS;
   }
 
   void setClangModuleCachePath(StringRef Path) {
@@ -273,6 +274,9 @@ class CompilerInvocation {
   /// C++ stdlib is the default for the specified target.
   void computeCXXStdlibOptions();
 
+  /// Compute whether or not we support aarch64TBI
+  void computeAArch64TBIOptions();
+
   /// Computes the runtime resource path relative to the given Swift
   /// executable.
   static void computeRuntimeResourcePathFromExecutablePath(
@@ -709,6 +713,12 @@ class CompilerInstance {
     }
   }
 
+  SourceFile &getPrimaryOrMainSourceFile() const {
+    if (SourceFile *SF = getPrimarySourceFile())
+      return *SF;
+    return getMainModule()->getMainSourceFile();
+  }
+
   /// Returns true if there was an error during setup.
   bool setup(const CompilerInvocation &Invocation, std::string &Error,
              ArrayRef<const char *> Args = {});
@@ -791,6 +801,9 @@ class CompilerInstance {
   /// \returns true if any errors occurred.
   bool performSILProcessing(SILModule *silModule);
 
+  /// Dumps any debugging output for the compilation, if requested.
+  void emitEndOfPipelineDebuggingOutput();
+
 private:
   /// Creates a new source file for the main module.
   SourceFile *createSourceFileForMainModule(ModuleDecl *mod,
diff --git a/include/swift/Frontend/FrontendInputsAndOutputs.h b/include/swift/Frontend/FrontendInputsAndOutputs.h
index 79de1de1c4040..200993d3308e0 100644
--- a/include/swift/Frontend/FrontendInputsAndOutputs.h
+++ b/include/swift/Frontend/FrontendInputsAndOutputs.h
@@ -253,6 +253,9 @@ class FrontendInputsAndOutputs {
   const PrimarySpecificPaths &
   getPrimarySpecificPathsForAtMostOnePrimary() const;
 
+  const PrimarySpecificPaths &
+  getPrimarySpecificPathsForRemaining(unsigned i) const;
+
   const PrimarySpecificPaths &
       getPrimarySpecificPathsForPrimary(StringRef) const;
 
diff --git a/include/swift/Frontend/FrontendOptions.h b/include/swift/Frontend/FrontendOptions.h
index 29a3f657f8fb0..68101735374a6 100644
--- a/include/swift/Frontend/FrontendOptions.h
+++ b/include/swift/Frontend/FrontendOptions.h
@@ -35,6 +35,21 @@ namespace llvm {
 namespace swift {
 enum class IntermoduleDepTrackingMode;
 
+/// Options for debugging the behavior of the frontend.
+struct CompilerDebuggingOptions {
+  /// Indicates whether or not the Clang importer should print statistics upon
+  /// termination.
+  bool PrintClangStats = false;
+
+  /// Indicates whether or not the availability scope trees built during
+  /// compilation should be dumped upon termination.
+  bool DumpAvailabilityScopes = false;
+
+  /// Indicates whether or not the Clang importer should dump lookup tables
+  /// upon termination.
+  bool DumpClangLookupTables = false;
+};
+
 /// Options for controlling the behavior of the frontend.
 class FrontendOptions {
   friend class ArgsToFrontendOptionsConverter;
@@ -51,14 +66,18 @@ class FrontendOptions {
 
   bool isOutputFileDirectory() const;
 
-  /// An Objective-C header to import and make implicitly visible.
+  /// A C header to import and make implicitly visible.
   std::string ImplicitObjCHeaderPath;
 
-  /// An Objective-C pch to import and make implicitly visible.
+  /// A C pch to import and make implicitly visible.
   std::string ImplicitObjCPCHPath;
 
+  /// Whether the imported C header or precompiled header is considered
+  /// an internal import (vs. the default, a public import).
+  bool ImportHeaderAsInternal = false;
+
   /// The map of aliases and real names of imported or referenced modules.
-  llvm::StringMap<StringRef> ModuleAliasMap;
+  llvm::StringMap<std::string> ModuleAliasMap;
 
   /// The name of the module that the frontend is building.
   std::string ModuleName;
@@ -92,9 +111,6 @@ class FrontendOptions {
   /// The path to which we should store indexing data, if any.
   std::string IndexStorePath;
 
-  /// The path to load access notes from.
-  std::string AccessNotesPath;
-
   /// The path to look in when loading a module interface file, to see if a
   /// binary module has already been built for use by the compiler.
   std::string PrebuiltModuleCachePath;
@@ -124,6 +140,9 @@ class FrontendOptions {
   /// A set of modules allowed to import this module.
   std::set<std::string> AllowableClients;
 
+  /// Options for debugging the compiler.
+  CompilerDebuggingOptions CompilerDebuggingOpts;
+
   /// Emit index data for imported serialized swift system modules.
   bool IndexSystemModules = false;
 
@@ -135,6 +154,9 @@ class FrontendOptions {
 
   /// Include local definitions/references in the index data.
   bool IndexIncludeLocals = false;
+  
+  /// Whether to compress the record and unit files in the index store.
+  bool IndexStoreCompress = false;
 
   bool SerializeDebugInfoSIL = false;
   /// If building a module from interface, ignore compiler flags
@@ -145,7 +167,7 @@ class FrontendOptions {
   std::string VerifyGenericSignaturesInModule;
 
   /// CacheReplay PrefixMap.
-  std::vector<std::string> CacheReplayPrefixMap;
+  std::vector<std::pair<std::string, std::string>> CacheReplayPrefixMap;
 
   /// Number of retry opening an input file if the previous opening returns
   /// bad file descriptor error.
@@ -164,9 +186,6 @@ class FrontendOptions {
     /// Parse and dump scope map.
     DumpScopeMaps,
 
-    /// Parse, type-check, and dump availability scopes
-    DumpAvailabilityScopes,
-
     EmitImportedModules, ///< Emit the modules that this one imports
     EmitPCH,             ///< Emit PCH of imported bridging header
 
@@ -201,7 +220,7 @@ class FrontendOptions {
 
     ScanDependencies, ///< Scan dependencies of Swift source files
     PrintVersion,     ///< Print version information.
-    PrintFeature,     ///< Print supported feature of this compiler
+    PrintArguments,   ///< Print supported arguments of this compiler
   };
 
   /// Indicates the action the user requested that the frontend perform.
@@ -279,11 +298,6 @@ class FrontendOptions {
   /// \see ModuleDecl::isImplicitDynamicEnabled
   bool EnableImplicitDynamic = false;
 
-  /// Enables the "fully resilient" resilience strategy.
-  ///
-  /// \see ResilienceStrategy::Resilient
-  bool EnableLibraryEvolution = false;
-
   /// If set, this module is part of a mixed Objective-C/Swift framework, and
   /// the Objective-C half should implicitly be visible to the Swift sources.
   bool ImportUnderlyingModule = false;
@@ -292,18 +306,16 @@ class FrontendOptions {
   /// by the Clang importer as part of semantic analysis.
   bool ModuleHasBridgingHeader = false;
 
+  /// Generate reproducer.
+  bool GenReproducer = false;
+
+  /// Directory to generate reproducer.
+  std::string GenReproducerDir;
+
   /// Indicates whether or not the frontend should print statistics upon
   /// termination.
   bool PrintStats = false;
 
-  /// Indicates whether or not the Clang importer should print statistics upon
-  /// termination.
-  bool PrintClangStats = false;
-
-  /// Indicates whether or not the Clang importer should dump lookup tables
-  /// upon termination.
-  bool DumpClangLookupTables = false;
-
   /// Indicates whether standard help should be shown.
   bool PrintHelp = false;
 
@@ -314,6 +326,14 @@ class FrontendOptions {
   /// exit.
   bool PrintTargetInfo = false;
 
+  /// Indicates that the frontend should print the static build configuration
+  /// information as JSON.
+  bool PrintBuildConfig = false;
+
+  /// Indicates that the frontend should print the supported features and then
+  /// exit.
+  bool PrintSupportedFeatures = false;
+
   /// See the \ref SILOptions.EmitVerboseSIL flag.
   bool EmitVerboseSIL = false;
 
@@ -595,6 +615,8 @@ class FrontendOptions {
   struct CustomAvailabilityDomains {
     /// Domains defined with `-define-enabled-availability-domain=`.
     llvm::SmallVector<std::string> EnabledDomains;
+    /// Domains defined with `-define-always-enabled-availability-domain=`.
+    llvm::SmallVector<std::string> AlwaysEnabledDomains;
     /// Domains defined with `-define-disabled-availability-domain=`.
     llvm::SmallVector<std::string> DisabledDomains;
     /// Domains defined with `-define-dynamic-availability-domain=`.
diff --git a/include/swift/Frontend/ModuleInterfaceLoader.h b/include/swift/Frontend/ModuleInterfaceLoader.h
index d6feda266222e..c1cbdb7ed7d85 100644
--- a/include/swift/Frontend/ModuleInterfaceLoader.h
+++ b/include/swift/Frontend/ModuleInterfaceLoader.h
@@ -111,6 +111,8 @@
 #include "swift/Frontend/Frontend.h"
 #include "swift/Frontend/ModuleInterfaceSupport.h"
 #include "swift/Serialization/SerializedModuleLoader.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/StringSaver.h"
 #include "llvm/Support/YAMLTraits.h"
@@ -150,7 +152,7 @@ class ExplicitSwiftModuleLoader: public SerializedModuleLoaderBase {
                   std::unique_ptr<llvm::MemoryBuffer> *moduleBuffer,
                   std::unique_ptr<llvm::MemoryBuffer> *moduleDocBuffer,
                   std::unique_ptr<llvm::MemoryBuffer> *moduleSourceInfoBuffer,
-                  bool skipBuildingInterface, bool isTestableDependencyLookup,
+                  bool isCanImportLookup, bool isTestableDependencyLookup,
                   bool &isFramework, bool &isSystemModule) override;
 
   std::error_code findModuleFilesInDirectory(
@@ -160,7 +162,7 @@ class ExplicitSwiftModuleLoader: public SerializedModuleLoaderBase {
       std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-      bool SkipBuildingInterface, bool IsFramework,
+      bool isCanImportLookup, bool IsFramework,
       bool IsTestableDependencyLookup = false) override;
 
   bool canImportModule(ImportPath::Module named, SourceLoc loc,
@@ -176,7 +178,7 @@ class ExplicitSwiftModuleLoader: public SerializedModuleLoaderBase {
   create(ASTContext &ctx,
          DependencyTracker *tracker, ModuleLoadingMode loadMode,
          StringRef ExplicitSwiftModuleMap,
-         const std::vector<std::pair<std::string, std::string>> &ExplicitSwiftModuleInputs,
+         const llvm::StringMap<std::string> &ExplicitSwiftModuleInputs,
          bool IgnoreSwiftSourceInfoFile);
 
   /// Append visible module names to \p names. Note that names are possibly
@@ -199,7 +201,7 @@ class ExplicitCASModuleLoader : public SerializedModuleLoaderBase {
                   std::unique_ptr<llvm::MemoryBuffer> *moduleBuffer,
                   std::unique_ptr<llvm::MemoryBuffer> *moduleDocBuffer,
                   std::unique_ptr<llvm::MemoryBuffer> *moduleSourceInfoBuffer,
-                  bool skipBuildingInterface, bool isTestableDependencyLookup,
+                  bool isCanImportLookup, bool isTestableDependencyLookup,
                   bool &isFramework, bool &isSystemModule) override;
 
   std::error_code findModuleFilesInDirectory(
@@ -209,7 +211,7 @@ class ExplicitCASModuleLoader : public SerializedModuleLoaderBase {
       std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-      bool SkipBuildingInterface, bool IsFramework,
+      bool IsCanImportLookup, bool IsFramework,
       bool IsTestableDependencyLookup = false) override;
 
   bool canImportModule(ImportPath::Module named, SourceLoc loc,
@@ -224,8 +226,7 @@ class ExplicitCASModuleLoader : public SerializedModuleLoaderBase {
   create(ASTContext &ctx, llvm::cas::ObjectStore &CAS,
          llvm::cas::ActionCache &cache, DependencyTracker *tracker,
          ModuleLoadingMode loadMode, StringRef ExplicitSwiftModuleMap,
-         const std::vector<std::pair<std::string, std::string>>
-             &ExplicitSwiftModuleInputs,
+         const llvm::StringMap<std::string> &ExplicitSwiftModuleInputs,
          bool IgnoreSwiftSourceInfoFile);
 
   /// Append visible module names to \p names. Note that names are possibly
@@ -318,7 +319,7 @@ class ExplicitModuleMapParser {
 public:
   ExplicitModuleMapParser(llvm::BumpPtrAllocator &Allocator) : Saver(Allocator) {}
 
-  std::error_code parseSwiftExplicitModuleMap(
+  llvm::Error parseSwiftExplicitModuleMap(
       llvm::MemoryBufferRef BufferRef,
       llvm::StringMap<ExplicitSwiftModuleInputInfo> &swiftModuleMap,
       llvm::StringMap<ExplicitClangModuleInputInfo> &clangModuleMap,
@@ -332,16 +333,15 @@ class ExplicitModuleMapParser {
       assert(DI != Stream.end() && "Failed to read a document");
       if (auto *MN = dyn_cast_or_null<SequenceNode>(DI->getRoot())) {
         for (auto &entry : *MN) {
-          if (parseSingleModuleEntry(entry, swiftModuleMap, clangModuleMap,
-                                     moduleAliases)) {
-            return std::make_error_code(std::errc::invalid_argument);
-          }
+          if (auto Err = parseSingleModuleEntry(entry, swiftModuleMap,
+                                                clangModuleMap, moduleAliases))
+            return Err;
         }
       } else {
-        return std::make_error_code(std::errc::invalid_argument);
+        return llvm::createStringError("invalid JSON root object");
       }
     }
-    return std::error_code{}; // success
+    return llvm::Error::success(); // success
   }
 
 private:
@@ -361,7 +361,7 @@ class ExplicitModuleMapParser {
       llvm_unreachable("Unexpected JSON value for isFramework");
   }
 
-  bool parseSingleModuleEntry(
+  llvm::Error parseSingleModuleEntry(
       llvm::yaml::Node &node,
       llvm::StringMap<ExplicitSwiftModuleInputInfo> &swiftModuleMap,
       llvm::StringMap<ExplicitClangModuleInputInfo> &clangModuleMap,
@@ -369,7 +369,7 @@ class ExplicitModuleMapParser {
     using namespace llvm::yaml;
     auto *mapNode = dyn_cast<MappingNode>(&node);
     if (!mapNode)
-      return true;
+      return llvm::createStringError("incorrect entry type");
     StringRef moduleName;
     std::optional<std::string> swiftModulePath, swiftModuleDocPath,
         swiftModuleSourceInfoPath, swiftModuleCacheKey, clangModuleCacheKey,
@@ -419,7 +419,7 @@ class ExplicitModuleMapParser {
       }
     }
     if (moduleName.empty())
-      return true;
+      return llvm::createStringError("entry is missing module name");
 
     bool didInsert;
     if (swiftModulePath.has_value()) {
@@ -446,17 +446,22 @@ class ExplicitModuleMapParser {
                                          clangModuleCacheKey);
       didInsert = clangModuleMap.try_emplace(moduleName, std::move(entry)).second;
     }
-    if (didInsert && moduleAlias.has_value()) {
+    if (!didInsert)
+      return llvm::createStringError(llvm::formatv(
+          "duplicate {0} module with name {1}",
+          swiftModulePath.has_value() ? "Swift" : "Clang", moduleName));
+
+    if (moduleAlias.has_value()) {
       moduleAliases[*moduleAlias] = moduleName;
     }
-    // Prevent duplicate module names.
-    return !didInsert;
+    return llvm::Error::success();
   }
 
   llvm::StringSaver Saver;
 };
 
-struct ModuleInterfaceLoaderOptions {
+class ModuleInterfaceLoaderOptions {
+public:
   FrontendOptions::ActionType requestedAction =
       FrontendOptions::ActionType::EmitModuleOnly;
   bool remarkOnRebuildFromInterface = false;
@@ -465,48 +470,12 @@ struct ModuleInterfaceLoaderOptions {
   bool disableBuildingInterface = false;
   bool downgradeInterfaceVerificationError = false;
   bool strictImplicitModuleContext = false;
+  CompilerDebuggingOptions compilerDebuggingOptions;
   std::string mainExecutablePath;
-  ModuleInterfaceLoaderOptions(const FrontendOptions &Opts):
-    remarkOnRebuildFromInterface(Opts.RemarkOnRebuildFromModuleInterface),
-    disableInterfaceLock(Opts.DisableInterfaceFileLock),
-    disableImplicitSwiftModule(Opts.DisableImplicitModules),
-    disableBuildingInterface(Opts.DisableBuildingInterface),
-    downgradeInterfaceVerificationError(Opts.DowngradeInterfaceVerificationError),
-    strictImplicitModuleContext(Opts.StrictImplicitModuleContext),
-    mainExecutablePath(Opts.MainExecutablePath)
-  {
-    switch (Opts.RequestedAction) {
-    case FrontendOptions::ActionType::TypecheckModuleFromInterface:
-      requestedAction = FrontendOptions::ActionType::Typecheck;
-      break;
-    case FrontendOptions::ActionType::ScanDependencies:
-      requestedAction = Opts.RequestedAction;
-      break;
-    default:
-      requestedAction = FrontendOptions::ActionType::EmitModuleOnly;
-      break;
-    }
-  }
-  ModuleInterfaceLoaderOptions() = default;
-};
-
-/// Strongly typed enum that represents if we require all SILModules to have
-/// OSSA modules emitted. This is implemented by incorporating this bit into the
-/// module cache hash.
-struct RequireOSSAModules_t {
-  enum ValueTy {
-    No = 0,
-    Yes = 1,
-  };
 
-  ValueTy value;
-
-  RequireOSSAModules_t(const SILOptions &opts)
-      : value(opts.EnableOSSAModules ? RequireOSSAModules_t::Yes
-                                     : RequireOSSAModules_t::No) {}
-
-  operator ValueTy() const { return value; }
-  explicit operator bool() const { return bool(value); }
+  ModuleInterfaceLoaderOptions(const FrontendOptions &Opts,
+                               bool inheritDebuggingOpts = false);
+  ModuleInterfaceLoaderOptions() = default;
 };
 
 class ModuleInterfaceCheckerImpl: public ModuleInterfaceChecker {
@@ -516,23 +485,20 @@ class ModuleInterfaceCheckerImpl: public ModuleInterfaceChecker {
   std::string PrebuiltCacheDir;
   std::string BackupInterfaceDir;
   ModuleInterfaceLoaderOptions Opts;
-  RequireOSSAModules_t RequiresOSSAModules;
 
 public:
   explicit ModuleInterfaceCheckerImpl(ASTContext &Ctx, StringRef cacheDir,
                                 StringRef prebuiltCacheDir,
                                 StringRef BackupInterfaceDir,
-                                ModuleInterfaceLoaderOptions opts,
-                                RequireOSSAModules_t requiresOSSAModules)
+                                ModuleInterfaceLoaderOptions opts)
       : Ctx(Ctx), CacheDir(cacheDir), PrebuiltCacheDir(prebuiltCacheDir),
         BackupInterfaceDir(BackupInterfaceDir),
-        Opts(opts), RequiresOSSAModules(requiresOSSAModules) {}
+        Opts(opts) {}
   explicit ModuleInterfaceCheckerImpl(ASTContext &Ctx, StringRef cacheDir,
                                 StringRef prebuiltCacheDir,
-                                ModuleInterfaceLoaderOptions opts,
-                                RequireOSSAModules_t requiresOSSAModules):
+                                ModuleInterfaceLoaderOptions opts):
     ModuleInterfaceCheckerImpl(Ctx, cacheDir, prebuiltCacheDir, StringRef(),
-                               opts, requiresOSSAModules) {}
+                               opts) {}
   std::vector<std::string>
   getCompiledModuleCandidatesForInterface(StringRef moduleName,
                                           StringRef interfacePath) override;
@@ -573,7 +539,7 @@ class ModuleInterfaceLoader : public SerializedModuleLoaderBase {
       std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-      bool SkipBuildingInterface, bool IsFramework,
+      bool IsCanImportLookup, bool IsFramework,
       bool IsTestableDependencyLookup = false) override;
 
   bool isCached(StringRef DepPath) override;
@@ -605,9 +571,9 @@ class ModuleInterfaceLoader : public SerializedModuleLoaderBase {
       StringRef CacheDir, StringRef PrebuiltCacheDir,
       StringRef BackupInterfaceDir, StringRef ModuleName, StringRef InPath,
       StringRef OutPath, StringRef ABIOutputPath,
+      ArrayRef<std::pair<std::string, std::string>> replayPrefixMap,
       bool SerializeDependencyHashes, bool TrackSystemDependencies,
       ModuleInterfaceLoaderOptions Opts,
-      RequireOSSAModules_t RequireOSSAModules,
       bool silenceInterfaceDiagnostics);
 
   /// Unconditionally build \p InPath (a swiftinterface file) to \p OutPath (as
@@ -677,8 +643,7 @@ struct InterfaceSubContextDelegateImpl : InterfaceSubContextDelegate {
                                      const LangOptions &LangOpts,
                                      const ClangImporterOptions &clangImporterOpts,
                                      const CASOptions &casOpts,
-                                     bool suppressRemarks,
-                                     RequireOSSAModules_t requireOSSAModules);
+                                     bool suppressNotes, bool suppressRemarks);
   bool extractSwiftInterfaceVersionAndArgs(CompilerInvocation &subInvocation,
                                            DiagnosticEngine &subInstanceDiags,
                                            SwiftInterfaceInfo &interfaceInfo,
@@ -692,8 +657,10 @@ struct InterfaceSubContextDelegateImpl : InterfaceSubContextDelegate {
       const ClangImporterOptions &clangImporterOpts, const CASOptions &casOpts,
       ModuleInterfaceLoaderOptions LoaderOpts, bool buildModuleCacheDirIfAbsent,
       StringRef moduleCachePath, StringRef prebuiltCachePath,
-      StringRef backupModuleInterfaceDir, bool serializeDependencyHashes,
-      bool trackSystemDependencies, RequireOSSAModules_t requireOSSAModules);
+      StringRef backupModuleInterfaceDir,
+      ArrayRef<std::pair<std::string, std::string>> replayPrefixMap,
+      bool serializeDependencyHashes,
+      bool trackSystemDependencies);
 
   template<typename ...ArgTypes>
   static InFlightDiagnostic diagnose(StringRef interfacePath,
diff --git a/include/swift/Frontend/SerializedDiagnosticConsumer.h b/include/swift/Frontend/SerializedDiagnosticConsumer.h
index 3445ae4054e9a..689cba3827280 100644
--- a/include/swift/Frontend/SerializedDiagnosticConsumer.h
+++ b/include/swift/Frontend/SerializedDiagnosticConsumer.h
@@ -37,6 +37,15 @@ namespace swift {
     /// \returns A new diagnostic consumer that serializes diagnostics.
     std::unique_ptr<DiagnosticConsumer>
     createConsumer(llvm::StringRef outputPath, bool emitMacroExpansionFiles);
+
+    /// Create a thread-safe DiagnosticConsumer that serializes diagnostics to a file,
+    /// using Clang's serialized diagnostics format.
+    ///
+    /// \param outputPath the file path to write the diagnostics to.
+    ///
+    /// \returns A new diagnostic consumer that serializes diagnostics.
+    std::unique_ptr<DiagnosticConsumer>
+    createThreadSafeConsumer(llvm::StringRef outputPath, bool emitMacroExpansionFiles);
   }
 }
 
diff --git a/include/swift/IDE/ArgumentCompletion.h b/include/swift/IDE/ArgumentCompletion.h
index cc1150d372385..1b7ff5c377df8 100644
--- a/include/swift/IDE/ArgumentCompletion.h
+++ b/include/swift/IDE/ArgumentCompletion.h
@@ -21,6 +21,8 @@
 namespace swift {
 namespace ide {
 
+struct Signature;
+
 class ArgumentTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
   struct Result {
     /// The type associated with the code completion expression itself.
@@ -75,6 +77,12 @@ class ArgumentTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
     /// functions is supported.
     bool IsInAsyncContext;
 
+    /// True if the function is an implicitly curried instance method.
+    bool IsImplicitlyCurried;
+
+    /// True if the call is the second apply of a double-applied function.
+    bool IsSecondApply;
+
     /// A bitfield to mark whether the parameter at a given index is optional.
     /// Parameters can be optional if they have a default argument or belong to
     /// a parameter pack.
@@ -117,9 +125,12 @@ class ArgumentTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
   /// \param IsLabeledTrailingClosure Whether we are completing the label of a
   /// labeled trailing closure, ie. if the code completion location is outside
   /// the call after the first trailing closure of the call.
-  void collectResults(bool IsLabeledTrailingClosure,
-                      SourceLoc Loc, DeclContext *DC,
-                      CodeCompletionContext &CompletionCtx);
+  void collectResults(bool IsLabeledTrailingClosure, SourceLoc Loc,
+                      DeclContext *DC, CodeCompletionContext &CompletionCtx);
+
+  /// Collects non-shadowed signature results into \p Signatures
+  void getSignatures(SourceLoc Loc, DeclContext *DC,
+                     SmallVectorImpl<Signature> &Signatures);
 };
 
 } // end namespace ide
diff --git a/include/swift/IDE/CodeCompletionContext.h b/include/swift/IDE/CodeCompletionContext.h
index b7625f1408d57..00c448ab02a37 100644
--- a/include/swift/IDE/CodeCompletionContext.h
+++ b/include/swift/IDE/CodeCompletionContext.h
@@ -86,6 +86,9 @@ class CodeCompletionContext {
     return CurrentResults.addCallWithNoDefaultArgs;
   }
 
+  void setVerifyUSRToDecl(bool flag) { CurrentResults.verifyUSRToDecl = flag; }
+  bool verifyUSRToDecl() const { return CurrentResults.verifyUSRToDecl; }
+
   /// Allocate a string owned by the code completion context.
   StringRef copyString(StringRef Str) {
     return Str.copy(*CurrentResults.Allocator);
diff --git a/include/swift/IDE/CodeCompletionResult.h b/include/swift/IDE/CodeCompletionResult.h
index 83b067aaa3eae..c9221ea6b30d3 100644
--- a/include/swift/IDE/CodeCompletionResult.h
+++ b/include/swift/IDE/CodeCompletionResult.h
@@ -16,6 +16,7 @@
 #include "swift/Basic/StringExtras.h"
 #include "swift/IDE/CodeCompletionResultType.h"
 #include "swift/IDE/CodeCompletionString.h"
+#include "swift/IDE/CommentConversion.h"
 
 namespace swift {
 namespace ide {
@@ -190,6 +191,7 @@ enum class CodeCompletionKeywordKind : uint8_t {
 enum class CompletionKind : uint8_t {
   None,
   Import,
+  Using,
   UnresolvedMember,
   DotExpr,
   StmtOrExpr,
@@ -378,6 +380,9 @@ class ContextFreeCodeCompletionResult {
   NullTerminatedStringRef ModuleName;
   NullTerminatedStringRef BriefDocComment;
   ArrayRef<NullTerminatedStringRef> AssociatedUSRs;
+  /// The Swift USR for a declaration (including for Clang declarations) used
+  /// for looking up the \c Decl instance for cached results.
+  NullTerminatedStringRef SwiftUSR;
   CodeCompletionResultType ResultType;
 
   ContextFreeNotRecommendedReason NotRecommended : 3;
@@ -410,7 +415,7 @@ class ContextFreeCodeCompletionResult {
       NullTerminatedStringRef ModuleName,
       NullTerminatedStringRef BriefDocComment,
       ArrayRef<NullTerminatedStringRef> AssociatedUSRs,
-      CodeCompletionResultType ResultType,
+      NullTerminatedStringRef SwiftUSR, CodeCompletionResultType ResultType,
       ContextFreeNotRecommendedReason NotRecommended,
       CodeCompletionDiagnosticSeverity DiagnosticSeverity,
       NullTerminatedStringRef DiagnosticMessage,
@@ -421,8 +426,8 @@ class ContextFreeCodeCompletionResult {
         HasAsyncAlternative(HasAsyncAlternative),
         CompletionString(CompletionString), ModuleName(ModuleName),
         BriefDocComment(BriefDocComment), AssociatedUSRs(AssociatedUSRs),
-        ResultType(ResultType), NotRecommended(NotRecommended),
-        DiagnosticSeverity(DiagnosticSeverity),
+        SwiftUSR(SwiftUSR), ResultType(ResultType),
+        NotRecommended(NotRecommended), DiagnosticSeverity(DiagnosticSeverity),
         DiagnosticMessage(DiagnosticMessage), FilterName(FilterName),
         NameForDiagnostics(NameForDiagnostics) {
     this->AssociatedKind.Opaque = AssociatedKind;
@@ -485,17 +490,16 @@ class ContextFreeCodeCompletionResult {
   /// \note The caller must ensure that the \p CompletionString and all
   /// \c StringRefs outlive this result, typically by storing them in the same
   /// \c CodeCompletionResultSink as the result itself.
-  static ContextFreeCodeCompletionResult *
-  createDeclResult(CodeCompletionResultSink &Sink,
-                   CodeCompletionString *CompletionString,
-                   const Decl *AssociatedDecl,
-                   bool HasAsyncAlternative, NullTerminatedStringRef ModuleName,
-                   NullTerminatedStringRef BriefDocComment,
-                   ArrayRef<NullTerminatedStringRef> AssociatedUSRs,
-                   CodeCompletionResultType ResultType,
-                   ContextFreeNotRecommendedReason NotRecommended,
-                   CodeCompletionDiagnosticSeverity DiagnosticSeverity,
-                   NullTerminatedStringRef DiagnosticMessage);
+  static ContextFreeCodeCompletionResult *createDeclResult(
+      CodeCompletionResultSink &Sink, CodeCompletionString *CompletionString,
+      const Decl *AssociatedDecl, bool HasAsyncAlternative,
+      NullTerminatedStringRef ModuleName,
+      NullTerminatedStringRef BriefDocComment,
+      ArrayRef<NullTerminatedStringRef> AssociatedUSRs,
+      NullTerminatedStringRef SwiftUSR, CodeCompletionResultType ResultType,
+      ContextFreeNotRecommendedReason NotRecommended,
+      CodeCompletionDiagnosticSeverity DiagnosticSeverity,
+      NullTerminatedStringRef DiagnosticMessage);
 
   CodeCompletionResultKind getKind() const { return Kind; }
 
@@ -539,6 +543,8 @@ class ContextFreeCodeCompletionResult {
     return AssociatedUSRs;
   }
 
+  NullTerminatedStringRef getSwiftUSR() const { return SwiftUSR; }
+
   const CodeCompletionResultType &getResultType() const { return ResultType; }
 
   ContextFreeNotRecommendedReason getNotRecommendedReason() const {
@@ -593,6 +599,10 @@ class ContextFreeCodeCompletionResult {
 /// the completion's usage context.
 class CodeCompletionResult {
   const ContextFreeCodeCompletionResult &ContextFree;
+  /// Contains the associated declaration if fetched; if not, stores the
+  /// ASTContext to use for finding the associated declaration through the Swift
+  /// USR.
+  mutable llvm::PointerUnion<const Decl *, ASTContext *> DeclOrCtx;
   SemanticContextKind SemanticContext : 3;
   static_assert(int(SemanticContextKind::MAX_VALUE) < 1 << 3, "");
 
@@ -621,13 +631,15 @@ class CodeCompletionResult {
   /// done by allocating the two in the same sink or adopting the context free
   /// sink in the sink that allocates this result.
   CodeCompletionResult(const ContextFreeCodeCompletionResult &ContextFree,
+                       llvm::PointerUnion<const Decl *, ASTContext *> DeclOrCtx,
                        SemanticContextKind SemanticContext,
                        CodeCompletionFlair Flair, uint8_t NumBytesToErase,
                        CodeCompletionResultTypeRelation TypeDistance,
                        ContextualNotRecommendedReason NotRecommended)
-      : ContextFree(ContextFree), SemanticContext(SemanticContext),
-        Flair(Flair.toRaw()), NotRecommended(NotRecommended),
-        NumBytesToErase(NumBytesToErase), TypeDistance(TypeDistance) {}
+      : ContextFree(ContextFree), DeclOrCtx(DeclOrCtx),
+        SemanticContext(SemanticContext), Flair(Flair.toRaw()),
+        NotRecommended(NotRecommended), NumBytesToErase(NumBytesToErase),
+        TypeDistance(TypeDistance) {}
 
   const ContextFreeCodeCompletionResult &getContextFreeResult() const {
     return ContextFree;
@@ -715,6 +727,9 @@ class CodeCompletionResult {
     }
   }
 
+  /// Finds the associated declaration on-demand and caches it.
+  const Decl *getAssociatedDecl() const;
+
   SemanticContextKind getSemanticContext() const { return SemanticContext; }
 
   CodeCompletionFlair getFlair() const { return CodeCompletionFlair(Flair); }
@@ -740,6 +755,26 @@ class CodeCompletionResult {
     return getContextFreeResult().getBriefDocComment();
   }
 
+  /// Prints the full documentation comment as XML to the provided \p OS stream.
+  ///
+  /// \returns true if the result has a documentation comment.
+  bool printFullDocCommentAsXML(raw_ostream &OS) const {
+    if (auto *D = getAssociatedDecl())
+      return ide::getDocumentationCommentAsXML(D, OS);
+
+    return false;
+  }
+
+  /// Prints the raw documentation comment to the provided \p OS stream.
+  ///
+  /// \returns true if the result has a documentation comment.
+  bool printRawDocComment(raw_ostream &OS) const {
+    if (auto *D = getAssociatedDecl())
+      return ide::getRawDocumentationComment(D, OS);
+
+    return false;
+  }
+
   ArrayRef<NullTerminatedStringRef> getAssociatedUSRs() const {
     return getContextFreeResult().getAssociatedUSRs();
   }
diff --git a/include/swift/IDE/CodeCompletionResultSink.h b/include/swift/IDE/CodeCompletionResultSink.h
index 4554698915d52..714d98f9d3e20 100644
--- a/include/swift/IDE/CodeCompletionResultSink.h
+++ b/include/swift/IDE/CodeCompletionResultSink.h
@@ -41,6 +41,9 @@ struct CodeCompletionResultSink {
   /// Whether to include an item without any default arguments.
   bool addCallWithNoDefaultArgs = true;
 
+  /// Whether to verify USR to \c Decl reconstruction during completion.
+  bool verifyUSRToDecl = false;
+
 private:
   /// Whether the code completion results computed for this sink are intended to
   /// only be stored in the cache. In this case no contextual information is
diff --git a/include/swift/IDE/CodeCompletionString.h b/include/swift/IDE/CodeCompletionString.h
index bfb9e4fa08762..0cedbae77cb9e 100644
--- a/include/swift/IDE/CodeCompletionString.h
+++ b/include/swift/IDE/CodeCompletionString.h
@@ -25,11 +25,11 @@
 namespace swift {
 namespace ide {
 
-class CodeCompletionResultBuilder;
+class CodeCompletionStringBuilder;
 
 namespace detail {
 class CodeCompletionStringChunk {
-  friend class swift::ide::CodeCompletionResultBuilder;
+  friend class swift::ide::CodeCompletionStringBuilder;
 
 public:
   enum class ChunkKind {
@@ -329,7 +329,6 @@ class CodeCompletionStringChunk {
 class alignas(detail::CodeCompletionStringChunk) CodeCompletionString final
     : private llvm::TrailingObjects<CodeCompletionString,
                                     detail::CodeCompletionStringChunk> {
-  friend class CodeCompletionResultBuilder;
   friend TrailingObjects;
 
 public:
@@ -348,9 +347,7 @@ class alignas(detail::CodeCompletionStringChunk) CodeCompletionString final
   static CodeCompletionString *create(llvm::BumpPtrAllocator &Allocator,
                                       ArrayRef<Chunk> Chunks);
 
-  ArrayRef<Chunk> getChunks() const {
-    return {getTrailingObjects<Chunk>(), NumChunks};
-  }
+  ArrayRef<Chunk> getChunks() const { return getTrailingObjects(NumChunks); }
 
   StringRef getFirstTextChunk(bool includeLeadingPunctuation = false) const;
   std::optional<unsigned>
diff --git a/include/swift/IDE/CodeCompletionStringPrinter.h b/include/swift/IDE/CodeCompletionStringPrinter.h
index c592886110764..55d12ae058797 100644
--- a/include/swift/IDE/CodeCompletionStringPrinter.h
+++ b/include/swift/IDE/CodeCompletionStringPrinter.h
@@ -26,7 +26,7 @@ class CodeCompletionStringPrinter : public ASTPrinter {
   using ChunkKind = CodeCompletionString::Chunk::ChunkKind;
 
 private:
-  CodeCompletionResultBuilder &Builder;
+  CodeCompletionStringBuilder &Builder;
   SmallString<16> Buffer;
   ChunkKind CurrChunkKind = ChunkKind::Text;
   ChunkKind NextChunkKind = ChunkKind::Text;
@@ -54,7 +54,7 @@ class CodeCompletionStringPrinter : public ASTPrinter {
   void setNextChunkKind(ChunkKind Kind) { NextChunkKind = Kind; }
 
 public:
-  CodeCompletionStringPrinter(CodeCompletionResultBuilder &Builder)
+  CodeCompletionStringPrinter(CodeCompletionStringBuilder &Builder)
       : Builder(Builder) {}
 
   ~CodeCompletionStringPrinter() {
diff --git a/include/swift/IDE/CompletionLookup.h b/include/swift/IDE/CompletionLookup.h
index 29a2f911b1913..1f8877da38206 100644
--- a/include/swift/IDE/CompletionLookup.h
+++ b/include/swift/IDE/CompletionLookup.h
@@ -24,7 +24,6 @@
 #include "swift/ClangImporter/ClangImporter.h"
 #include "swift/IDE/CodeCompletionContext.h"
 #include "swift/IDE/CodeCompletionResult.h"
-#include "swift/IDE/CodeCompletionStringPrinter.h"
 #include "swift/IDE/PossibleParamInfo.h"
 #include "swift/Parse/IDEInspectionCallbacks.h"
 #include "swift/Sema/IDETypeChecking.h"
@@ -33,6 +32,8 @@
 namespace swift {
 namespace ide {
 
+class CodeCompletionResultBuilder;
+
 using DeclFilter =
     std::function<bool(ValueDecl *, DeclVisibilityKind, DynamicLookupInfo)>;
 
@@ -325,6 +326,8 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
 
   void addImportModuleNames();
 
+  void addUsingSpecifiers();
+
   SemanticContextKind getSemanticContext(const Decl *D,
                                          DeclVisibilityKind Reason,
                                          DynamicLookupInfo dynamicLookupInfo);
@@ -352,12 +355,6 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
       GenericSignature genericSig = GenericSignature(),
       bool dynamicOrOptional = false);
 
-  /// For printing in code completion results, replace archetypes with
-  /// protocol compositions.
-  ///
-  /// FIXME: Perhaps this should be an option in PrintOptions instead.
-  Type eraseArchetypes(Type type, GenericSignature genericSig);
-
   Type getTypeOfMember(const ValueDecl *VD,
                        DynamicLookupInfo dynamicLookupInfo);
 
@@ -372,32 +369,8 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
   void addVarDeclRef(const VarDecl *VD, DeclVisibilityKind Reason,
                      DynamicLookupInfo dynamicLookupInfo);
 
-  static bool hasInterestingDefaultValue(const ParamDecl *param);
-
   bool shouldAddItemWithoutDefaultArgs(const AbstractFunctionDecl *func);
 
-  /// Build argument patterns for calling. Returns \c true if any content was
-  /// added to \p Builder. If \p declParams is non-empty, the size must match
-  /// with \p typeParams.
-  bool addCallArgumentPatterns(CodeCompletionResultBuilder &Builder,
-                               ArrayRef<AnyFunctionType::Param> typeParams,
-                               ArrayRef<const ParamDecl *> declParams,
-                               GenericSignature genericSig,
-                               bool includeDefaultArgs = true);
-
-  /// Build argument patterns for calling. Returns \c true if any content was
-  /// added to \p Builder. If \p Params is non-nullptr, \F
-  bool addCallArgumentPatterns(CodeCompletionResultBuilder &Builder,
-                               const AnyFunctionType *AFT,
-                               const ParameterList *Params,
-                               GenericSignature genericSig,
-                               bool includeDefaultArgs = true);
-
-  static void addEffectsSpecifiers(CodeCompletionResultBuilder &Builder,
-                                   const AnyFunctionType *AFT,
-                                   const AbstractFunctionDecl *AFD,
-                                   bool forceAsync = false);
-
   void addPoundAvailable(std::optional<StmtKind> ParentKind);
 
   void addPoundSelector(bool needPound);
@@ -458,6 +431,8 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
   void addEnumElementRef(const EnumElementDecl *EED, DeclVisibilityKind Reason,
                          DynamicLookupInfo dynamicLookupInfo,
                          bool HasTypeContext);
+  void addMacroCallArguments(const MacroDecl *MD, DeclVisibilityKind Reason,
+                             bool forTrivialTrailingClosure = false);
   void addMacroExpansion(const MacroDecl *MD, DeclVisibilityKind Reason);
 
   void addKeyword(
diff --git a/include/swift/IDE/CompletionOverrideLookup.h b/include/swift/IDE/CompletionOverrideLookup.h
index 89641e48b78d9..a547f06e8a7d6 100644
--- a/include/swift/IDE/CompletionOverrideLookup.h
+++ b/include/swift/IDE/CompletionOverrideLookup.h
@@ -21,6 +21,8 @@
 namespace swift {
 namespace ide {
 
+class CodeCompletionResultBuilder;
+
 class CompletionOverrideLookup : public swift::VisibleDeclConsumer {
   CodeCompletionResultSink &Sink;
   ASTContext &Ctx;
diff --git a/include/swift/IDE/IDEBridging.h b/include/swift/IDE/IDEBridging.h
index dbbed37e48cbb..d1dac6b59eee2 100644
--- a/include/swift/IDE/IDEBridging.h
+++ b/include/swift/IDE/IDEBridging.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022 - 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,8 +15,7 @@
 
 #include "swift/Basic/BasicBridging.h"
 
-#ifdef USED_IN_CPP_SOURCE
-#include "swift/Basic/SourceLoc.h"
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 #include "llvm/CAS/CASReference.h"
 #include <optional>
 #include <vector>
@@ -66,7 +65,7 @@ enum class LabelRangeType {
 
 enum class ResolvedLocContext { Default, Selector, Comment, StringLiteral };
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 struct ResolvedLoc {
   /// The range of the call's base name.
   swift::CharSourceRange range;
@@ -105,7 +104,7 @@ struct ResolvedLoc {
   ResolvedLoc();
 };
 
-#endif // USED_IN_CPP_SOURCE
+#endif // #ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 
 /// An opaque, heap-allocated `ResolvedLoc`.
 ///
@@ -118,12 +117,12 @@ struct BridgedResolvedLoc {
   /// This consumes `labelRanges` by calling `takeUnbridged` on it.
   SWIFT_NAME(
       "init(range:labelRanges:firstTrailingLabel:labelType:isActive:context:)")
-  BridgedResolvedLoc(BridgedCharSourceRange range,
+  BridgedResolvedLoc(swift::CharSourceRange range,
                      BridgedCharSourceRangeVector labelRanges,
                      unsigned firstTrailingLabel, LabelRangeType labelType,
                      bool isActive, ResolvedLocContext context);
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
   ResolvedLoc takeUnbridged() {
     ResolvedLoc *resolvedLocPtr = static_cast<ResolvedLoc *>(resolvedLoc);
     ResolvedLoc unbridged = *resolvedLocPtr;
@@ -153,7 +152,7 @@ class BridgedResolvedLocVector {
   SWIFT_NAME("append(_:)")
   void push_back(BridgedResolvedLoc Loc);
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
   std::vector<ResolvedLoc> takeUnbridged() {
     std::vector<ResolvedLoc> *vectorPtr =
         static_cast<std::vector<ResolvedLoc> *>(vector);
diff --git a/include/swift/IDE/ModuleInterfacePrinting.h b/include/swift/IDE/ModuleInterfacePrinting.h
index fc51d5e287d83..178f7758944bc 100644
--- a/include/swift/IDE/ModuleInterfacePrinting.h
+++ b/include/swift/IDE/ModuleInterfacePrinting.h
@@ -38,11 +38,14 @@ namespace ide {
 /// Flags used when traversing a module for printing.
 enum class ModuleTraversal : unsigned {
   /// Visit modules even if their contents wouldn't be visible to name lookup.
-  VisitHidden     = 0x01,
+  VisitHidden = 0x01,
   /// Visit submodules.
   VisitSubmodules = 0x02,
   /// Skip the declarations in a Swift overlay module.
-  SkipOverlay     = 0x04,
+  SkipOverlay = 0x04,
+  /// Visit exported modules where their public module name matches the current
+  /// module.
+  VisitMatchingExported = 0x08,
 };
 
 /// Options used to describe the traversal of a module for printing.
diff --git a/include/swift/IDE/PostfixCompletion.h b/include/swift/IDE/PostfixCompletion.h
index 0e7953b5baf50..b9bb8f62a4239 100644
--- a/include/swift/IDE/PostfixCompletion.h
+++ b/include/swift/IDE/PostfixCompletion.h
@@ -86,10 +86,6 @@ class PostfixCompletionCallback : public TypeCheckCompletionCallback {
   PostfixCompletionCallback(CodeCompletionExpr *CompletionExpr, DeclContext *DC)
       : CompletionExpr(CompletionExpr), DC(DC) {}
 
-  /// Typecheck the code completion expression in isolation, calling
-  /// \c sawSolution for each solution formed.
-  void fallbackTypeCheck(DeclContext *DC) override;
-
   /// Deliver code completion results that were discoverd by \c sawSolution to
   /// \p Consumer.
   /// \param DotLoc If we are completing after a dot, the location of the dot,
diff --git a/include/swift/IDE/SignatureHelp.h b/include/swift/IDE/SignatureHelp.h
new file mode 100644
index 0000000000000..1eeaedc193062
--- /dev/null
+++ b/include/swift/IDE/SignatureHelp.h
@@ -0,0 +1,72 @@
+//===--- SignatureHelp.h --- ------------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_IDE_SIGNATURE_HELP_H
+#define SWIFT_IDE_SIGNATURE_HELP_H
+
+#include "swift/AST/Type.h"
+#include "swift/Basic/LLVM.h"
+#include "swift/IDE/TypeCheckCompletionCallback.h"
+
+namespace swift {
+class IDEInspectionCallbacksFactory;
+
+namespace ide {
+
+struct Signature {
+  /// True if this is a subscript rather than a function call.
+  bool IsSubscript;
+
+  /// True if the function is an implicitly curried instance method.
+  bool IsImplicitlyCurried;
+
+  /// True if the call is the second apply of a double-applied function.
+  bool IsSecondApply;
+
+  /// The FuncDecl or SubscriptDecl associated with the call.
+  ValueDecl *FuncD;
+
+  /// The type of the function being called.
+  AnyFunctionType *FuncTy;
+
+  /// The base type of the call/subscript (null for free functions).
+  Type BaseType;
+
+  /// The index of the parameter corresponding to the completion argument.
+  std::optional<unsigned> ParamIdx;
+};
+
+struct SignatureHelpResult {
+  /// The decl context of the parsed expression.
+  DeclContext *DC;
+
+  /// Suggested signatures.
+  SmallVector<Signature, 2> Signatures;
+
+  SignatureHelpResult(DeclContext *DC) : DC(DC) {}
+};
+
+/// An abstract base class for consumers of signatures results.
+class SignatureHelpConsumer {
+public:
+  virtual ~SignatureHelpConsumer() {}
+  virtual void handleResult(const SignatureHelpResult &result) = 0;
+};
+
+/// Create a factory for code completion callbacks.
+IDEInspectionCallbacksFactory *
+makeSignatureHelpCallbacksFactory(SignatureHelpConsumer &Consumer);
+
+} // namespace ide
+} // namespace swift
+
+#endif // SWIFT_IDE_SIGNATURE_HELP_H
diff --git a/include/swift/IDE/SignatureHelpFormatter.h b/include/swift/IDE/SignatureHelpFormatter.h
new file mode 100644
index 0000000000000..03e3bf43b72a6
--- /dev/null
+++ b/include/swift/IDE/SignatureHelpFormatter.h
@@ -0,0 +1,85 @@
+//===--- SignatureHelpFormatter.h --- ---------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_IDE_SIGNATURE_HELP_FORMATTER_H
+#define SWIFT_IDE_SIGNATURE_HELP_FORMATTER_H
+
+#include "swift/IDE/SignatureHelp.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Allocator.h"
+
+namespace swift {
+
+class DeclContext;
+
+namespace ide {
+
+class CodeCompletionString;
+
+struct FormattedSignatureHelp {
+  struct Parameter {
+    /// The offset of the parameter text in the signature text.
+    unsigned Offset;
+
+    /// The length of the parameter text in the signature text.
+    unsigned Length;
+
+    /// The internal parameter name.
+    llvm::StringRef Name;
+
+    Parameter() {}
+  };
+
+  struct Signature {
+    llvm::StringRef Text;
+    llvm::StringRef DocComment;
+    std::optional<unsigned> ActiveParam;
+    llvm::ArrayRef<Parameter> Params;
+
+    Signature(llvm::StringRef Text, llvm::StringRef DocComment,
+              std::optional<unsigned> ActiveParam,
+              llvm::ArrayRef<Parameter> Params)
+        : Text(Text), DocComment(DocComment), ActiveParam(ActiveParam),
+          Params(Params) {}
+  };
+
+  llvm::ArrayRef<Signature> Signatures;
+  unsigned ActiveSignature;
+
+  FormattedSignatureHelp(llvm::ArrayRef<Signature> Signatures,
+                         unsigned ActiveSignature)
+      : Signatures(Signatures), ActiveSignature(ActiveSignature) {}
+};
+
+class SignatureHelpFormatter {
+private:
+  llvm::BumpPtrAllocator &Allocator;
+
+public:
+  SignatureHelpFormatter(llvm::BumpPtrAllocator &Allocator)
+      : Allocator(Allocator) {}
+
+  FormattedSignatureHelp format(ide::SignatureHelpResult Result);
+
+private:
+  FormattedSignatureHelp::Signature
+  formatSignature(const DeclContext *DC, const ide::Signature &Signature);
+
+  CodeCompletionString *createSignatureString(const ide::Signature &Signature,
+                                              const DeclContext *DC);
+};
+
+} // namespace ide
+} // namespace swift
+
+#endif // SWIFT_IDE_SIGNATURE_HELP_FORMATTER_H
diff --git a/include/swift/IDE/SourceEntityWalker.h b/include/swift/IDE/SourceEntityWalker.h
index 4a65fd970fb81..6a79486ca084a 100644
--- a/include/swift/IDE/SourceEntityWalker.h
+++ b/include/swift/IDE/SourceEntityWalker.h
@@ -140,7 +140,7 @@ class SourceEntityWalker {
   /// refers to.
   /// \param ExtTyRef this is set when the entity is a reference to a type loc
   /// in \c ExtensionDecl.
-  virtual bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
+  virtual bool visitDeclReference(ValueDecl *D, SourceRange Range,
                                   TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef,
                                   Type T, ReferenceMetaData Data);
 
@@ -156,7 +156,7 @@ class SourceEntityWalker {
   /// \param Data whether this is a read, write or read/write access, etc.
   /// \param IsOpenBracket this is \c true when the method is called on an
   /// open bracket.
-  virtual bool visitSubscriptReference(ValueDecl *D, CharSourceRange Range,
+  virtual bool visitSubscriptReference(ValueDecl *D, SourceRange Range,
                                        ReferenceMetaData Data,
                                        bool IsOpenBracket);
 
@@ -167,7 +167,7 @@ class SourceEntityWalker {
   /// \param D the referenced decl.
   /// \param Range the source range of the source reference.
   /// \param Data whether this is a read, write or read/write access, etc.
-  virtual bool visitCallAsFunctionReference(ValueDecl *D, CharSourceRange Range,
+  virtual bool visitCallAsFunctionReference(ValueDecl *D, SourceRange Range,
                                             ReferenceMetaData Data);
 
   /// This method is called for each keyword argument in a call expression.
diff --git a/include/swift/IDE/TypeCheckCompletionCallback.h b/include/swift/IDE/TypeCheckCompletionCallback.h
index 6bf5e3ad4e481..8432f58afb479 100644
--- a/include/swift/IDE/TypeCheckCompletionCallback.h
+++ b/include/swift/IDE/TypeCheckCompletionCallback.h
@@ -59,10 +59,6 @@ class TypeCheckCompletionCallback {
   /// True if at least one solution was passed via the \c sawSolution
   /// callback.
   bool gotCallback() const { return GotCallback; }
-
-  /// Typecheck the code completion expression in its outermost expression
-  /// context, calling \c sawSolution for each solution formed.
-  virtual void fallbackTypeCheck(DeclContext *DC);
 };
 
 // MARK: - Utility functions for subclasses of TypeCheckCompletionCallback
@@ -90,19 +86,16 @@ struct WithSolutionSpecificVarTypesRAII {
 
   WithSolutionSpecificVarTypesRAII(
       llvm::SmallDenseMap<const VarDecl *, Type> SolutionSpecificVarTypes) {
-    for (auto SolutionVarType : SolutionSpecificVarTypes) {
-      if (SolutionVarType.first->hasInterfaceType()) {
-        RestoreVarTypes[SolutionVarType.first] =
-            SolutionVarType.first->getInterfaceType();
+    for (auto &[var, ty] : SolutionSpecificVarTypes) {
+      if (var->hasInterfaceType()) {
+        RestoreVarTypes[var] = var->getInterfaceType();
       } else {
-        RestoreVarTypes[SolutionVarType.first] = Type();
+        RestoreVarTypes[var] = Type();
       }
-      if (!SolutionVarType.second->hasArchetype()) {
-        setInterfaceType(const_cast<VarDecl *>(SolutionVarType.first),
-                         SolutionVarType.second);
+      if (!ty->hasArchetype()) {
+        setInterfaceType(const_cast<VarDecl *>(var), ty);
       } else {
-        setInterfaceType(const_cast<VarDecl *>(SolutionVarType.first),
-                         ErrorType::get(SolutionVarType.second));
+        setInterfaceType(const_cast<VarDecl *>(var), ErrorType::get(ty));
       }
     }
   }
diff --git a/include/swift/IDE/Utils.h b/include/swift/IDE/Utils.h
index 343a5ca533f38..e7ff7fbc1f720 100644
--- a/include/swift/IDE/Utils.h
+++ b/include/swift/IDE/Utils.h
@@ -402,7 +402,8 @@ struct ResolvedRangeInfo {
                     /*Single entry*/true, /*UnhandledEffects*/{},
                     OrphanKind::None, {}, {}, {}) {}
   ResolvedRangeInfo(): ResolvedRangeInfo(ArrayRef<Token>()) {}
-  void print(llvm::raw_ostream &OS) const;
+  void print(llvm::raw_ostream &OS,
+             const PrintOptions &PO = PrintOptions()) const;
   ExitState exit() const { return ExitInfo.Exit; }
   Type getType() const { return ExitInfo.ReturnType; }
 
diff --git a/include/swift/IDETool/CompileInstance.h b/include/swift/IDETool/CompileInstance.h
index 4d904568517d1..5e6b7b7dc4f95 100644
--- a/include/swift/IDETool/CompileInstance.h
+++ b/include/swift/IDETool/CompileInstance.h
@@ -33,7 +33,6 @@ namespace ide {
 class CompileInstance {
   const std::string &SwiftExecutablePath;
   const std::string &RuntimeResourcePath;
-  const std::string &DiagnosticDocumentationPath;
   const std::shared_ptr<swift::PluginRegistry> Plugins;
 
   struct Options {
@@ -70,12 +69,10 @@ class CompileInstance {
 public:
   CompileInstance(const std::string &SwiftExecutablePath,
                   const std::string &RuntimeResourcePath,
-                  const std::string &DiagnosticDocumentationPath,
                   std::shared_ptr<swift::PluginRegistry> Plugins = nullptr)
       : SwiftExecutablePath(SwiftExecutablePath),
-        RuntimeResourcePath(RuntimeResourcePath),
-        DiagnosticDocumentationPath(DiagnosticDocumentationPath),
-        Plugins(Plugins), CachedCIInvalidated(false), CachedReuseCount(0) {}
+        RuntimeResourcePath(RuntimeResourcePath), Plugins(Plugins),
+        CachedCIInvalidated(false), CachedReuseCount(0) {}
 
   /// NOTE: \p Args is only used for checking the equaity of the invocation.
   /// Since this function assumes that it is already normalized, exact the same
diff --git a/include/swift/IDETool/CompilerInvocation.h b/include/swift/IDETool/CompilerInvocation.h
index 4b15f322f9933..c98f886d2e2d5 100644
--- a/include/swift/IDETool/CompilerInvocation.h
+++ b/include/swift/IDETool/CompilerInvocation.h
@@ -27,8 +27,7 @@ bool initCompilerInvocation(
     StringRef UnresolvedPrimaryFile,
     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
     const std::string &swiftExecutablePath,
-    const std::string &runtimeResourcePath,
-    const std::string &diagnosticDocumentationPath, time_t sessionTimestamp,
+    const std::string &runtimeResourcePath, time_t sessionTimestamp,
     std::string &Error);
 
 bool initInvocationByClangArguments(ArrayRef<const char *> ArgList,
diff --git a/include/swift/IDETool/IDEInspectionInstance.h b/include/swift/IDETool/IDEInspectionInstance.h
index 0f3ab25f7f09b..95afeec267ec0 100644
--- a/include/swift/IDETool/IDEInspectionInstance.h
+++ b/include/swift/IDETool/IDEInspectionInstance.h
@@ -21,6 +21,7 @@
 #include "swift/IDE/ConformingMethodList.h"
 #include "swift/IDE/CursorInfo.h"
 #include "swift/IDE/ImportDepth.h"
+#include "swift/IDE/SignatureHelp.h"
 #include "swift/IDE/SwiftCompletionInfo.h"
 #include "swift/IDE/TypeContextInfo.h"
 #include "llvm/ADT/Hashing.h"
@@ -80,6 +81,14 @@ struct ConformingMethodListResults {
   bool DidReuseAST;
 };
 
+/// The results returned from \c IDEInspectionInstance::signatures.
+struct SignatureHelpResults {
+  /// The actual results. If \c nullptr, no results were found.
+  const SignatureHelpResult *Result;
+  /// Whether an AST was reused to produce the results.
+  bool DidReuseAST;
+};
+
 /// The results returned from \c IDEInspectionInstance::cursorInfo.
 struct CursorInfoResults {
   /// The actual results.
@@ -206,6 +215,15 @@ class IDEInspectionInstance {
       llvm::function_ref<void(CancellableResult<ConformingMethodListResults>)>
           Callback);
 
+  void signatureHelp(
+      swift::CompilerInvocation &Invocation, llvm::ArrayRef<const char *> Args,
+      llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
+      llvm::MemoryBuffer *ideInspectionTargetBuffer, unsigned int Offset,
+      DiagnosticConsumer *DiagC,
+      std::shared_ptr<std::atomic<bool>> CancellationFlag,
+      llvm::function_ref<void(CancellableResult<SignatureHelpResults>)>
+          Callback);
+
   void cursorInfo(
       swift::CompilerInvocation &Invocation, llvm::ArrayRef<const char *> Args,
       llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
diff --git a/include/swift/IRGen/GenericRequirement.h b/include/swift/IRGen/GenericRequirement.h
index 3722cb2252ede..5d8714fe661be 100644
--- a/include/swift/IRGen/GenericRequirement.h
+++ b/include/swift/IRGen/GenericRequirement.h
@@ -109,6 +109,11 @@ class GenericRequirement {
   bool isAnyWitnessTable() const {
     return kind == Kind::WitnessTable || kind == Kind::WitnessTablePack;
   }
+
+  bool isAnyPack() const {
+    return kind == Kind::MetadataPack || kind == Kind::WitnessTablePack;
+  }
+
   bool isValue() const {
     return kind == Kind::Value;
   }
diff --git a/include/swift/IRGen/Linking.h b/include/swift/IRGen/Linking.h
index 78ac19c0c8817..7570d5ac7c3fd 100644
--- a/include/swift/IRGen/Linking.h
+++ b/include/swift/IRGen/Linking.h
@@ -57,15 +57,10 @@ class UniversalLinkageInfo {
   /// be promoted to public external. Used by the LLDB expression evaluator.
   bool ForcePublicDecls;
 
-  /// When true, allows duplicate external and hidden declarations by marking
-  /// them as linkonce / weak.
-  bool MergeableSymbols;
-
   explicit UniversalLinkageInfo(IRGenModule &IGM);
 
   UniversalLinkageInfo(const llvm::Triple &triple, bool hasMultipleIGMs,
-                       bool forcePublicDecls, bool isStaticLibrary,
-                       bool mergeableSymbols);
+                       bool forcePublicDecls, bool isStaticLibrary);
 
   /// In case of multiple llvm modules (in multi-threaded compilation) all
   /// private decls must be visible from other files.
@@ -132,7 +127,7 @@ class LinkEntity {
   /// ValueDecl*, SILFunction*, or TypeBase*, depending on Kind.
   void *Pointer;
 
-  /// ProtocolConformance*, depending on Kind.
+  /// ProtocolConformance* or SILDifferentiabilityWitness*, depending on Kind.
   void *SecondaryPointer;
 
   /// A hand-rolled bitfield with the following layout:
@@ -772,8 +767,8 @@ class LinkEntity {
   void
   setForDifferentiabilityWitness(Kind kind,
                                  const SILDifferentiabilityWitness *witness) {
-    Pointer = const_cast<void *>(static_cast<const void *>(witness));
-    SecondaryPointer = nullptr;
+    Pointer = nullptr;
+    SecondaryPointer = const_cast<void *>(static_cast<const void *>(witness));
     Data = LINKENTITY_SET_FIELD(Kind, unsigned(kind));
   }
 
@@ -1043,7 +1038,7 @@ class LinkEntity {
   }
 
   static LinkEntity forPropertyDescriptor(AbstractStorageDecl *decl) {
-    assert(decl->exportsPropertyDescriptor());
+    assert((bool)decl->getPropertyDescriptorGenericSignature());
     LinkEntity entity;
     entity.setForDecl(Kind::PropertyDescriptor, decl);
     return entity;
@@ -1684,7 +1679,7 @@ class LinkEntity {
 
   SILDifferentiabilityWitness *getSILDifferentiabilityWitness() const {
     assert(getKind() == Kind::DifferentiabilityWitness);
-    return reinterpret_cast<SILDifferentiabilityWitness *>(Pointer);
+    return reinterpret_cast<SILDifferentiabilityWitness *>(SecondaryPointer);
   }
 
   const RootProtocolConformance *getRootProtocolConformance() const {
@@ -1850,6 +1845,14 @@ class LinkEntity {
   bool isTypeKind() const { return isTypeKind(getKind()); }
 
   bool isAlwaysSharedLinkage() const;
+
+  /// Whether the link entity's definitions must be considered non-unique.
+  ///
+  /// This applies only in the Embedded Swift linkage model, and is used for
+  /// any symbols that have not been explicitly requested to have unique
+  /// definitions (e.g., with @_used).
+  bool hasNonUniqueDefinition() const;
+
 #undef LINKENTITY_GET_FIELD
 #undef LINKENTITY_SET_FIELD
 
diff --git a/include/swift/Index/IndexRecord.h b/include/swift/Index/IndexRecord.h
index c2d21994afe7c..db526df5fd75a 100644
--- a/include/swift/Index/IndexRecord.h
+++ b/include/swift/Index/IndexRecord.h
@@ -56,7 +56,7 @@ namespace index {
 bool indexAndRecord(SourceFile *primarySourceFile, StringRef indexUnitToken,
                     StringRef indexStorePath, bool indexClangModules,
                     bool indexSystemModules, bool skipStdlib,
-                    bool includeLocals, bool isDebugCompilation,
+                    bool includeLocals, bool compress, bool isDebugCompilation,
                     bool isExplicitModuleBuild, StringRef targetTriple,
                     const DependencyTracker &dependencyTracker,
                     const PathRemapper &pathRemapper);
@@ -98,7 +98,7 @@ bool indexAndRecord(SourceFile *primarySourceFile, StringRef indexUnitToken,
 bool indexAndRecord(ModuleDecl *module, ArrayRef<std::string> indexUnitTokens,
                     StringRef moduleUnitToken, StringRef indexStorePath,
                     bool indexClangModules, bool indexSystemModules,
-                    bool skipStdlib, bool includeLocals,
+                    bool skipStdlib, bool includeLocals, bool compress,
                     bool isDebugCompilation, bool isExplicitModuleBuild,
                     StringRef targetTriple,
                     const DependencyTracker &dependencyTracker,
diff --git a/include/swift/Markup/AST.h b/include/swift/Markup/AST.h
index c48e8fa624989..d1cfbb813053c 100644
--- a/include/swift/Markup/AST.h
+++ b/include/swift/Markup/AST.h
@@ -112,11 +112,11 @@ class Document final : public MarkupASTNode,
                           ArrayRef<MarkupASTNode *> Children);
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -136,11 +136,11 @@ class BlockQuote final : public MarkupASTNode,
   static BlockQuote *create(MarkupContext &MC, ArrayRef<MarkupASTNode *> Children);
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -162,17 +162,16 @@ class List final : public MarkupASTNode,
                       bool IsOrdered);
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   void setChildren(ArrayRef<MarkupASTNode *> NewChildren) {
     assert(NewChildren.size() <= NumChildren);
-    std::copy(NewChildren.begin(), NewChildren.end(),
-              getTrailingObjects<MarkupASTNode *>());
+    std::copy(NewChildren.begin(), NewChildren.end(), getTrailingObjects());
     NumChildren = NewChildren.size();
   }
 
@@ -197,11 +196,11 @@ class Item final : public MarkupASTNode,
   static Item *create(MarkupContext &MC, ArrayRef<MarkupASTNode *> Children);
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -265,11 +264,11 @@ class Paragraph final : public MarkupASTNode,
                            ArrayRef<MarkupASTNode *> Children);
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -291,11 +290,11 @@ class Header final : public MarkupASTNode,
                         ArrayRef<MarkupASTNode *> Children);
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   unsigned getLevel() const {
@@ -482,11 +481,11 @@ class Emphasis final : public InlineContent,
                           ArrayRef<MarkupASTNode *> Children);
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -506,11 +505,11 @@ class Strong final : public InlineContent,
                         ArrayRef<MarkupASTNode *> Children);
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -536,11 +535,11 @@ class Link final : public InlineContent,
   StringRef getDestination() const { return Destination; }
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -577,11 +576,11 @@ class Image final : public InlineContent,
   }
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -607,11 +606,11 @@ class InlineAttributes final : public InlineContent, private llvm::TrailingObjec
   StringRef getAttributes() const { return Attributes; }
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -678,11 +677,11 @@ class ParamField final : public PrivateExtension,
   }
 
   ArrayRef<MarkupASTNode *> getChildren() {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   ArrayRef<const MarkupASTNode *> getChildren() const {
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren};
+    return getTrailingObjects(NumChildren);
   }
 
   static bool classof(const MarkupASTNode *N) {
@@ -703,11 +702,11 @@ public: \
   static Id *create(MarkupContext &MC, ArrayRef<MarkupASTNode *> Children); \
 \
   ArrayRef<MarkupASTNode *> getChildren() { \
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren}; \
+    return getTrailingObjects(NumChildren); \
   } \
 \
   ArrayRef<const MarkupASTNode *> getChildren() const { \
-    return {getTrailingObjects<MarkupASTNode *>(), NumChildren}; \
+    return getTrailingObjects(NumChildren); \
   } \
 \
   static bool classof(const MarkupASTNode *N) { \
diff --git a/include/swift/Migrator/FixitApplyDiagnosticConsumer.h b/include/swift/Migrator/FixitApplyDiagnosticConsumer.h
index 4937a881b827d..ce5aebf58f5e9 100644
--- a/include/swift/Migrator/FixitApplyDiagnosticConsumer.h
+++ b/include/swift/Migrator/FixitApplyDiagnosticConsumer.h
@@ -21,7 +21,7 @@
 #include "swift/Migrator/FixitFilter.h"
 #include "swift/Migrator/Migrator.h"
 #include "swift/Migrator/Replacement.h"
-#include "clang/Rewrite/Core/RewriteBuffer.h"
+#include "llvm/ADT/RewriteBuffer.h"
 #include "llvm/ADT/SmallSet.h"
 
 namespace swift {
@@ -37,7 +37,7 @@ struct Replacement;
 
 class FixitApplyDiagnosticConsumer final
   : public DiagnosticConsumer, public FixitFilter {
-  clang::RewriteBuffer RewriteBuf;
+  llvm::RewriteBuffer RewriteBuf;
 
   /// The entire text of the input file.
   const StringRef Text;
diff --git a/include/swift/Migrator/RewriteBufferEditsReceiver.h b/include/swift/Migrator/RewriteBufferEditsReceiver.h
index 91c86d893bc6d..e9366ead711f5 100644
--- a/include/swift/Migrator/RewriteBufferEditsReceiver.h
+++ b/include/swift/Migrator/RewriteBufferEditsReceiver.h
@@ -16,7 +16,7 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Edit/EditsReceiver.h"
-#include "clang/Rewrite/Core/RewriteBuffer.h"
+#include "llvm/ADT/RewriteBuffer.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/raw_ostream.h"
 
@@ -26,12 +26,13 @@ namespace swift {
 namespace migrator {
 
 /// An EditsReceiver that collects edits from an EditedSource and directly
-/// applies it to a clang::RewriteBuffer.
+/// applies it to a llvm::RewriteBuffer.
 class RewriteBufferEditsReceiver final : public clang::edit::EditsReceiver {
   const clang::SourceManager &ClangSourceManager;
   const clang::FileID InputFileID;
   const StringRef InputText;
-  clang::RewriteBuffer RewriteBuf;
+  llvm::RewriteBuffer RewriteBuf;
+
 public:
   RewriteBufferEditsReceiver(const clang::SourceManager &ClangSourceManager,
                              const clang::FileID InputFileID,
diff --git a/include/swift/Option/FrontendOptions.td b/include/swift/Option/FrontendOptions.td
index 40e071a8facf5..b72721ee4e3ca 100644
--- a/include/swift/Option/FrontendOptions.td
+++ b/include/swift/Option/FrontendOptions.td
@@ -165,6 +165,8 @@ def verify_apply_fixes : Flag<["-"], "verify-apply-fixes">,
   HelpText<"Like -verify, but updates the original source file">;
 def verify_ignore_unknown: Flag<["-"], "verify-ignore-unknown">,
   HelpText<"Allow diagnostics for '<unknown>' location in verify mode">;
+def verify_ignore_unrelated: Flag<["-"], "verify-ignore-unrelated">,
+  HelpText<"Allow diagnostics in files outside those with expected diagnostics in verify mode">;
 def verify_generic_signatures : Separate<["-"], "verify-generic-signatures">,
   MetaVarName<"<module-name>">,
   HelpText<"Verify the generic signatures in the given module">;
@@ -244,6 +246,9 @@ def module_can_import_version: MultiArg<["-"], "module-can-import-version", 3>,
   MetaVarName<"<moduleName> <version> <underlyingVersion>">,
   HelpText<"Specify canImport module and versions">;
 
+def module_import_from_cas: Flag<["-"], "module-import-from-cas">,
+  HelpText<"Import modules from CAS instead of file system">;
+
 def disable_cross_import_overlay_search: Flag<["-"], "disable-cross-import-overlay-search">,
   HelpText<"Disable searching for cross import overlay file">;
 
@@ -255,10 +260,6 @@ def const_gather_protocols_file
   : Separate<["-"], "const-gather-protocols-file">, MetaVarName<"<path>">,
     HelpText<"Specify a list of protocols for extraction of conformances' const values'">;
 
-def placeholder_dependency_module_map
-  : Separate<["-"], "placeholder-dependency-module-map-file">, MetaVarName<"<path>">,
-    HelpText<"Specify a JSON file containing information of external Swift module dependencies">;
-
 def import_prescan : Flag<["-"], "import-prescan">,
    HelpText<"When performing a dependency scan, only identify all imports of the main Swift module sources">;
 
@@ -283,12 +284,12 @@ def no_parallel_scan : Flag<["-"], "no-parallel-scan">,
    HelpText<"Perform dependency scanning in a single-threaded fashion.">;
 
 def enable_copy_propagation : Flag<["-"], "enable-copy-propagation">,
-  HelpText<"Run SIL copy propagation with lexical lifetimes to shorten object "
+  HelpText<"Always run SIL copy propagation with lexical lifetimes to shorten object "
            "lifetimes while preserving variable lifetimes.">;
 def copy_propagation_state_EQ :
   Joined<["-"], "enable-copy-propagation=">,
   HelpText<"Whether to enable copy propagation">,
-  MetaVarName<"true|requested-passes-only|false">;
+  MetaVarName<"always|optimizing|requested-passes-only|false">;
 
 def disable_infer_public_concurrent_value : Flag<["-"], "disable-infer-public-sendable">,
     HelpText<"Disable inference of Sendable conformances for public structs and enums">;
@@ -319,6 +320,12 @@ let Flags = [FrontendOption, NoDriverOption, HelpHidden, ModuleInterfaceOptionIg
     Joined<["-"], "formal-cxx-interoperability-mode=">,
     HelpText<"What version of C++ interoperability a textual interface was originally generated with">,
     MetaVarName<"<cxx-interop-version>|off">;
+  def enable_assembly_vision_all
+      : Flag<["-"], "enable-assembly-vision-all">,
+        HelpText<"Enable assembly vision for all functions">;
+  def disable_assembly_vision_all
+      : Flag<["-"], "disable-assembly-vision-all">,
+        HelpText<"Disable assembly vision for all functions">;
 }
 
 // Flags that are saved into module interfaces
@@ -388,10 +395,6 @@ def public_autolink_library :
 // HIDDEN FLAGS
 let Flags = [FrontendOption, NoDriverOption, HelpHidden] in {
 
-def enable_experimental_swift_based_closure_specialization :
-  Flag<["-"], "experimental-swift-based-closure-specialization">,
-  HelpText<"Use the experimental Swift based closure-specialization optimization pass instead of the existing C++ one">;
-
 def checked_async_objc_bridging : Joined<["-"], "checked-async-objc-bridging=">,
   HelpText<"Control whether checked continuations are used when bridging "
            "async calls from Swift to ObjC: 'on', 'off' ">;
@@ -428,6 +431,9 @@ def dump_macro_expansions : Flag<["-"], "dump-macro-expansions">,
 def emit_macro_expansion_files : Separate<["-"], "emit-macro-expansion-files">,
   HelpText<"Specify when to emit macro expansion file: 'none', 'debug', or 'diagnostics'">;
 
+def dump_source_file_imports : Flag<["-"], "dump-source-file-imports">,
+  HelpText<"Dumps the list of imports for each source file">;
+
 def analyze_request_evaluator : Flag<["-"], "analyze-request-evaluator">,
   Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
   HelpText<"Print out request evaluator cache statistics at the end of the compilation job">;
@@ -448,6 +454,14 @@ def requirement_machine_max_concrete_nesting : Joined<["-"], "requirement-machin
   Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
   HelpText<"Set the maximum concrete type nesting depth before giving up">;
 
+def requirement_machine_max_concrete_size : Joined<["-"], "requirement-machine-max-concrete-size=">,
+  Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
+  HelpText<"Set the maximum concrete type total size before giving up">;
+
+def requirement_machine_max_type_differences : Joined<["-"], "requirement-machine-max-type-differences=">,
+  Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
+  HelpText<"Set the maximum number of type difference structures allocated before giving up">;
+
 def requirement_machine_max_split_concrete_equiv_class_attempts : Joined<["-"], "requirement-machine-max-split-concrete-equiv-class-attempts=">,
   Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
   HelpText<"Set the maximum concrete number of attempts at splitting "
@@ -467,6 +481,14 @@ def disable_requirement_machine_reuse : Flag<["-"], "disable-requirement-machine
 def enable_requirement_machine_opaque_archetypes : Flag<["-"], "enable-requirement-machine-opaque-archetypes">,
   HelpText<"Enable more correct opaque archetype support, which is off by default because it might fail to produce a convergent rewrite system">;
 
+def max_substitution_depth : Joined<["-"], "max-substitution-depth=">,
+  Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
+  HelpText<"Set the maximum nesting depth for type substitution operations">;
+
+def max_substitution_count : Joined<["-"], "max-substitution-count=">,
+  Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
+  HelpText<"Set the maximum step count for type substitution operations">;
+
 def dump_type_witness_systems : Flag<["-"], "dump-type-witness-systems">,
   HelpText<"Enables dumping type witness systems from associated type inference">;
 
@@ -519,6 +541,10 @@ def disable_clangimporter_source_import : Flag<["-"],
   "disable-clangimporter-source-import">,
   HelpText<"Disable ClangImporter and forward all requests straight the DWARF importer.">;
 
+def disable_const_value_importing : Flag<["-"],
+  "disable-const-value-importing">,
+  HelpText<"Disable constant value importing in ClangImporter.">;
+
 def disable_implicit_concurrency_module_import : Flag<["-"],
   "disable-implicit-concurrency-module-import">,
   HelpText<"Disable the implicit import of the _Concurrency module.">;
@@ -654,6 +680,9 @@ def dump_clang_lookup_tables : Flag<["-"], "dump-clang-lookup-tables">,
   HelpText<"Dump the importer's Swift-name-to-Clang-name lookup tables to "
            "stderr">;
 
+def dump_availability_scopes : Flag<["-"], "dump-availability-scopes">,
+                               HelpText<"Dump availability scopes to stderr">;
+
 def disable_modules_validate_system_headers : Flag<["-"], "disable-modules-validate-system-headers">,
   HelpText<"Disable validating system headers in the Clang importer">;
 
@@ -666,6 +695,9 @@ def emit_pch : Flag<["-"], "emit-pch">,
 def pch_disable_validation : Flag<["-"], "pch-disable-validation">,
   HelpText<"Disable validating the persistent PCH">;
 
+def version_independent_apinotes : Flag<["-"], "version-independent-apinotes">,
+  HelpText<"Input clang modules carry all versioned APINotes">;
+
 def disable_sil_ownership_verifier : Flag<["-"], "disable-sil-ownership-verifier">,
   HelpText<"Do not verify ownership invariants during SIL Verification ">;
 
@@ -840,6 +872,9 @@ def downgrade_typecheck_interface_error : Flag<["-"], "downgrade-typecheck-inter
 def enable_volatile_modules : Flag<["-"], "enable-volatile-modules">,
   HelpText<"Load Swift modules in memory">;
 
+def solver_memory_threshold_EQ : Joined<["-"], "solver-memory-threshold=">,
+  HelpText<"Set the upper bound for memory consumption, in bytes, by the constraint solver">;
+
 def solver_expression_time_threshold_EQ : Joined<["-"], "solver-expression-time-threshold=">,
   HelpText<"Expression type checking timeout, in seconds">;
 
@@ -849,15 +884,17 @@ def solver_scope_threshold_EQ : Joined<["-"], "solver-scope-threshold=">,
 def solver_trail_threshold_EQ : Joined<["-"], "solver-trail-threshold=">,
   HelpText<"Expression type checking trail change limit">;
 
-def solver_disable_shrink :
-  Flag<["-"], "solver-disable-shrink">,
-  HelpText<"Disable the shrink phase of expression type checking">;
+def solver_disable_prepared_overloads : Flag<["-"], "solver-disable-prepared-overloads">,
+  HelpText<"Disable experimental prepared overloads optimization">;
+
+def solver_enable_prepared_overloads : Flag<["-"], "solver-enable-prepared-overloads">,
+  HelpText<"Enable experimental prepared overloads optimization">;
 
 def solver_disable_splitter : Flag<["-"], "solver-disable-splitter">,
   HelpText<"Disable the component splitter phase of expression type checking">;
 
-def disable_constraint_solver_performance_hacks : Flag<["-"], "disable-constraint-solver-performance-hacks">,
-  HelpText<"Disable all the hacks in the constraint solver">;
+def enable_constraint_solver_performance_hacks : Flag<["-"], "enable-constraint-solver-performance-hacks">,
+  HelpText<"Enable all the old hacks in the constraint solver">;
 
 def enable_operator_designated_types :
   Flag<["-"], "enable-operator-designated-types">,
@@ -874,6 +911,12 @@ def disable_invalid_ephemeralness_as_error :
 def switch_checking_invocation_threshold_EQ : Joined<["-"],
     "switch-checking-invocation-threshold=">;
 
+def dynamic_member_lookup_depth_limit_EQ
+    : Joined<["-"], "dynamic-member-lookup-depth-limit=">,
+      HelpText<
+          "The maximum number of dynamic member lookups that can be chained "
+          "to resolve a member reference">;
+
 def enable_new_operator_lookup :
   Flag<["-"], "enable-new-operator-lookup">,
   HelpText<"Enable the new operator decl and precedencegroup lookup behavior">;
@@ -1175,12 +1218,22 @@ def enable_arm64_corocc : Flag<["-"], "enable-arm64-corocc">,
 def disable_arm64_corocc : Flag<["-"], "disable-arm64-corocc">,
   HelpText<"Don't use swiftcorocc for yield_once_2 routines on arm64 variants.">;
 
+def enable_callee_allocated_coro_abi : Flag<["-"], "enable-callee-allocated-coro-abi">,
+  HelpText<"Override per-platform settings and use yield_once_2.">;
+
+def disable_callee_allocated_coro_abi : Flag<["-"], "disable-callee-allocated-coro-abi">,
+  HelpText<"Override per-platform settings and don't use yield_once_2.">;
+
 def enable_cond_fail_message_annotation : Flag<["-"], "enable-cond-fail-message-annotation">,
   HelpText<"Enable cond_fail message annotation. Will serialize a .o.yaml file per .o file.">;
 
 def disable_cond_fail_message_annotation : Flag<["-"], "dissable-cond-fail-message-annotation">,
   HelpText<"Disable cond_fail message annotation.">;
 
+def min_valid_pointer_value : Joined<["-"], "min-valid-pointer-value=">,
+  MetaVarName<"<value>">,
+  HelpText<"Overrides the target's least valid pointer value.'">;
+
 let Flags = [FrontendOption, NoDriverOption, HelpHidden, ModuleInterfaceOptionIgnorable] in {
   def enable_pack_metadata_stack_promotion :
     Joined<["-"], "enable-pack-metadata-stack-promotion=">,
@@ -1265,8 +1318,7 @@ def disable_ast_verifier : Flag<["-"], "disable-ast-verifier">,
 
 let Flags = [FrontendOption, NoDriverOption, HelpHidden, ModuleInterfaceOptionIgnorable] in {
   def enable_ossa_modules : Flag<["-"], "enable-ossa-modules">,
-    HelpText<"Always serialize SIL in ossa form. If this flag is not passed in, "
-            "when optimizing ownership will be lowered before serializing SIL">;
+    HelpText<"Obsolete. This option is ignored">;
 }
 
 def enable_recompilation_to_ossa_module : Flag<["-"], "enable-recompilation-to-ossa-module">,
@@ -1448,9 +1500,6 @@ def bridging_header_pch_key : Separate<["-"], "bridging-header-pch-key">,
 def no_clang_include_tree: Flag<["-"], "no-clang-include-tree">,
   HelpText<"Do not use clang include tree, fallback to use CAS filesystem to build clang modules">;
 
-def cas_fs: Separate<["-"], "cas-fs">,
-  HelpText<"Root CASID for CAS FileSystem">, MetaVarName<"<cas-id>">;
-
 def clang_include_tree_root: Separate<["-"], "clang-include-tree-root">,
   HelpText<"Clang Include Tree CASID">, MetaVarName<"<cas-id>">;
 def clang_include_tree_filelist: Separate<["-"], "clang-include-tree-filelist">,
@@ -1485,7 +1534,7 @@ def platform_c_calling_convention_EQ :
 
 def disable_sending_args_and_results_with_region_isolation : Flag<["-"],
   "disable-sending-args-and-results-with-region-based-isolation">,
-  HelpText<"Disable sending args and results when region based isolation is enabled. Only enabled with asserts">,
+  HelpText<"Disable sending args and results when region-based isolation is enabled. Only enabled with asserts">,
   Flags<[HelpHidden]>;
 
 def scanner_module_validation: Flag<["-"], "scanner-module-validation">,
@@ -1512,6 +1561,12 @@ def enable_address_dependencies : Flag<["-"], "enable-address-dependencies">,
 def disable_address_dependencies : Flag<["-"], "disable-address-dependencies">,
   HelpText<"Disable enforcement of lifetime dependencies on addressable values.">;
 
+def gen_reproducer : Flag<["-"], "gen-reproducer">,
+                     HelpText<"Generate a reproducer for current compilation.">;
+def gen_reproducer_dir
+    : Separate<["-"], "gen-reproducer-dir">,
+      HelpText<"Path to directory where reproducers write to.">;
+
 } // end let Flags = [FrontendOption, NoDriverOption, HelpHidden]
 
 def disable_experimental_parser_round_trip : Flag<["-"],
diff --git a/include/swift/Option/Options.td b/include/swift/Option/Options.td
index 664572632985d..99f714fd22e4d 100644
--- a/include/swift/Option/Options.td
+++ b/include/swift/Option/Options.td
@@ -33,7 +33,7 @@ def ModuleWrapOption : OptionFlag;
 def NoDriverOption : OptionFlag;
 
 // Some options should not be available depending on whether this is the
-// interactive driver 'swift', or the batch compiler 'swiftc'.
+// interactive driver 'swift', or the aot compiler 'swiftc'.
 def NoInteractiveOption : OptionFlag;
 def NoBatchOption : OptionFlag;
 
@@ -298,6 +298,13 @@ def language_mode : Separate<["-"], "language-mode">,
   MetaVarName<"<mode>">,
   Alias<swift_version>;
 
+def min_swift_runtime_version
+    : Separate<["-"], "min-swift-runtime-version">,
+      Flags<[FrontendOption, ModuleInterfaceOptionIgnorable]>,
+      HelpText<"The minimum Swift runtime version "
+               "that will be available at runtime">,
+      MetaVarName<"<vers>">;
+
 def package_description_version: Separate<["-"], "package-description-version">,
   Flags<[FrontendOption, HelpHidden, ModuleInterfaceOption]>,
   HelpText<"The version number to be applied on the input for the PackageDescription availability kind">,
@@ -328,7 +335,7 @@ def F_EQ : Joined<["-"], "F=">, Flags<[FrontendOption, ArgumentIsPath]>,
 
 def Fsystem : Separate<["-"], "Fsystem">,
   Flags<[FrontendOption, ArgumentIsPath, SwiftSymbolGraphExtractOption,
-         SwiftSynthesizeInterfaceOption]>,
+         SwiftAPIDigesterOption, SwiftSynthesizeInterfaceOption]>,
   HelpText<"Add directory to system framework search path">;
 
 def I : JoinedOrSeparate<["-"], "I">,
@@ -340,23 +347,32 @@ def I_EQ : Joined<["-"], "I=">, Flags<[FrontendOption, ArgumentIsPath]>,
 
 def Isystem : Separate<["-"], "Isystem">,
   Flags<[FrontendOption, ArgumentIsPath, SwiftSymbolGraphExtractOption,
-         SwiftSynthesizeInterfaceOption]>,
+         SwiftAPIDigesterOption, SwiftSynthesizeInterfaceOption]>,
   HelpText<"Add directory to the system import search path">;
 
 def import_underlying_module : Flag<["-"], "import-underlying-module">,
   Flags<[FrontendOption, NoInteractiveOption]>,
   HelpText<"Implicitly imports the Objective-C half of a module">;
 
-def import_objc_header : Separate<["-"], "import-objc-header">,
-  Flags<[FrontendOption, HelpHidden, ArgumentIsPath]>,
-  HelpText<"Implicitly imports an Objective-C header file">;
 def import_bridging_header : Separate<["-"], "import-bridging-header">,
+  Flags<[FrontendOption, ArgumentIsPath]>,
+  HelpText<"Implicitly imports a C header file">;
+def import_objc_header : Separate<["-"], "import-objc-header">,
   Flags<[FrontendOption, HelpHidden, ArgumentIsPath]>,
-  Alias<import_objc_header>;
+  Alias<import_bridging_header>;
+
+def internal_import_bridging_header : Separate<["-"], "internal-import-bridging-header">,
+  Flags<[FrontendOption, ArgumentIsPath]>,
+  HelpText<"Implicitly imports a C header file as an internal import">;
+
 def import_pch : Separate<["-"], "import-pch">,
   Flags<[FrontendOption, HelpHidden, ArgumentIsPath]>,
   HelpText<"Import bridging header PCH file">;
 
+def internal_import_pch : Separate<["-"], "internal-import-pch">,
+  Flags<[FrontendOption, HelpHidden, ArgumentIsPath]>,
+  HelpText<"Import bridging header PCH file as internal">;
+
 def pch_output_dir: Separate<["-"], "pch-output-dir">,
   Flags<[FrontendOption, HelpHidden, ArgumentIsPath]>,
   HelpText<"Directory to persist automatically created precompiled bridging headers">;
@@ -468,10 +484,6 @@ def remark_module_serialization : Flag<["-"], "Rmodule-serialization">,
   Flags<[FrontendOption, DoesNotAffectIncrementalBuild]>,
   HelpText<"Emit remarks about module serialization">;
 
-def remark_abi_inference : Flag<["-"], "Rabi-inference">,
-  Flags<[FrontendOption, DoesNotAffectIncrementalBuild]>,
-  HelpText<"Emit a remark when an '@abi' attribute adds an attribute or modifier to the ABI declaration based on its presence in the API">;
-
 def emit_tbd : Flag<["-"], "emit-tbd">,
   HelpText<"Emit a TBD file">,
   Flags<[FrontendOption, NoInteractiveOption, SupplementaryOutput]>;
@@ -580,6 +592,14 @@ def define_enabled_availability_domain : Separate<["-"], "define-enabled-availab
     HelpText<"Defines a custom availability domain that is available at compile time">,
     MetaVarName<"<domain>">;
 
+def define_always_enabled_availability_domain
+    : Separate<["-"], "define-always-enabled-availability-domain">,
+      Flags<[HelpHidden, FrontendOption, NoInteractiveOption,
+             ModuleInterfaceOptionIgnorable]>,
+      HelpText<"Defines a custom availability domain that is available for all "
+               "deployments">,
+      MetaVarName<"<domain>">;
+
 def define_disabled_availability_domain : Separate<["-"], "define-disabled-availability-domain">,
     Flags<[HelpHidden, FrontendOption, NoInteractiveOption, ModuleInterfaceOptionIgnorable]>,
     HelpText<"Defines a custom availability domain that is unavailable at compile time">,
@@ -803,10 +823,6 @@ def import_cf_types : Flag<["-"], "import-cf-types">,
   Flags<[FrontendOption, HelpHidden]>,
   HelpText<"Recognize and import CF types as class types">;
 
-def solver_memory_threshold : Separate<["-"], "solver-memory-threshold">,
-  Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
-  HelpText<"Set the upper bound for memory consumption, in bytes, by the constraint solver">;
-
 def solver_shrink_unsolved_threshold : Separate<["-"], "solver-shrink-unsolved-threshold">,
 Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
 HelpText<"Set The upper bound to number of sub-expressions unsolved before termination of the shrink phrase">;
@@ -875,7 +891,7 @@ def cxx_interoperability_mode :
 def experimental_c_foreign_reference_types :
   Flag<["-"], "experimental-c-foreign-reference-types">,
   Flags<[FrontendOption, HelpHidden, ModuleInterfaceOption]>,
-  HelpText<"Enable experimental C foreign references types (with reference counting).">;
+  HelpText<"Enable experimental C foreign references types. Deprecated, has no effect.">;
 
 def experimental_hermetic_seal_at_link:
   Flag<["-"], "experimental-hermetic-seal-at-link">,
@@ -890,7 +906,7 @@ def experimental_package_interface_load:
 def experimental_serialize_debug_info:
   Flag<["-"], "experimental-serialize-debug-info">,
   Flags<[FrontendOption, HelpHidden]>,
-  HelpText<"Enables seriailzation/deserialization of debug scopes">;
+  HelpText<"Enables serialization/deserialization of debug scopes">;
 // Diagnostic control options
 def suppress_warnings : Flag<["-"], "suppress-warnings">,
   Flags<[FrontendOption]>,
@@ -920,6 +936,10 @@ def Wwarning : Separate<["-"], "Wwarning">,
   MetaVarName<"<diagnostic_group>">,
   HelpText<"Treat this warning group as warning">;
 
+def suppress_notes : Flag<["-"], "suppress-notes">,
+  Flags<[FrontendOption]>,
+  HelpText<"Suppress all notes">;
+
 def suppress_remarks : Flag<["-"], "suppress-remarks">,
   Flags<[FrontendOption]>,
   HelpText<"Suppress all remarks">;
@@ -998,16 +1018,6 @@ def default_isolation_EQ :  Joined<["-"], "default-isolation=">,
   Flags<[FrontendOption]>,
   Alias<default_isolation>;
 
-def executor_factory : JoinedOrSeparate<["-"], "executor-factory">,
-  Flags<[FrontendOption]>,
-  HelpText<"Specify the factory to use to create the default executors for "
-           "Swift Concurrency.  This must be a type conforming to the "
-           "'ExecutorFactory' protocol.">,
-  MetaVarName<"<factory-type>">;
-def executor_factory_EQ : Joined<["-"], "executor-factory=">,
-  Flags<[FrontendOption]>,
-  Alias<executor_factory>;
-
 def enable_experimental_feature :
   Separate<["-"], "enable-experimental-feature">,
   Flags<[FrontendOption, ModuleInterfaceOption]>,
@@ -1032,6 +1042,10 @@ def strict_memory_safety : Flag<["-"], "strict-memory-safety">,
   Flags<[FrontendOption, ModuleInterfaceOptionIgnorable,
          SwiftAPIDigesterOption, SwiftSynthesizeInterfaceOption]>,
   HelpText<"Enable strict memory safety checking">;
+def strict_memory_safety_migrate : Flag<["-"], "strict-memory-safety:migrate">,
+  Flags<[FrontendOption, ModuleInterfaceOptionIgnorable,
+         SwiftAPIDigesterOption, SwiftSynthesizeInterfaceOption]>,
+  HelpText<"Enable migration to strict memory safety checking">;
 
 def Rpass_EQ : Joined<["-"], "Rpass=">,
   Flags<[FrontendOption]>,
@@ -1051,7 +1065,7 @@ def save_optimization_record_EQ : Joined<["-"], "save-optimization-record=">,
            "(default: YAML)">, MetaVarName<"<format>">;
 def save_optimization_record_path :
   Separate<["-"], "save-optimization-record-path">,
-  Flags<[FrontendOption, ArgumentIsPath]>,
+  Flags<[FrontendOption, ArgumentIsPath, CacheInvariant]>,
   HelpText<"Specify the file name of any generated optimization record">;
 def save_optimization_record_passes :
   Separate<["-"], "save-optimization-record-passes">,
@@ -1177,7 +1191,7 @@ def ExperimentalPackageCMO : Flag<["-"], "experimental-package-cmo">,
 
 def PackageCMO : Flag<["-"], "package-cmo">,
   Flags<[FrontendOption]>,
-  HelpText<"Enable optimization to perform defalut CMO within a package boundary">;
+  HelpText<"Enable optimization to perform default CMO within a package boundary">;
 
 def EnableDefaultCMO : Flag<["-"], "enable-default-cmo">,
   Flags<[HelpHidden, FrontendOption]>,
@@ -1449,11 +1463,7 @@ def dump_scope_maps : Separate<["-"], "dump-scope-maps">,
   MetaVarName<"<expanded-or-list-of-line:column>">,
   ModeOpt,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
-def dump_availability_scopes :
-  Flag<["-"], "dump-availability-scopes">,
-  HelpText<"Type-check input file(s) and dump availability scopes">,
-  ModeOpt,
-  Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
+
 def dump_type_info : Flag<["-"], "dump-type-info">,
   HelpText<"Output YAML dump of fixed-size types from all imported modules">,
   ModeOpt,
@@ -1543,6 +1553,13 @@ def target_legacy_spelling : Joined<["--"], "target=">,
 def print_target_info : Flag<["-"], "print-target-info">,
     Flags<[FrontendOption]>,
     HelpText<"Print target information for the given target <triple>, such as x86_64-apple-macos10.9">, MetaVarName<"<triple>">;
+def print_static_build_config : Flag<["-"], "print-static-build-config">,
+    Flags<[FrontendOption]>,
+    HelpText<"Print static build configuration that can be used to evaluate #ifs in Swift source code">;
+
+def print_supported_features : Flag<["-"], "print-supported-features">,
+    Flags<[FrontendOption]>,
+    HelpText<"Print information about features supported by the compiler">;
 
 def target_cpu : Separate<["-"], "target-cpu">, Flags<[FrontendOption, ModuleInterfaceOption]>,
   HelpText<"Generate code for a particular CPU variant">;
@@ -1577,6 +1594,10 @@ def explain_module_dependency_detailed : Separate<["-"], "explain-module-depende
 def explicit_auto_linking : Flag<["-"], "explicit-auto-linking">,
   Flags<[NewDriverOnlyOption]>,
   HelpText<"Instead of linker-load directives, have the driver specify all link dependencies on the linker invocation. Requires '-explicit-module-build'.">;
+  
+def experimental_emit_variant_module : Flag<["-"], "experimental-emit-variant-module">,
+  Flags<[NewDriverOnlyOption]>,
+  HelpText<"When a target variant triple is specified, the same driver invocation will emit two Swift modules, one for the primary target and one for the variant.">;
 
 def min_inlining_target_version : Separate<["-"], "target-min-inlining-version">,
   Flags<[FrontendOption, ModuleInterfaceOption]>,
@@ -1660,9 +1681,13 @@ def scan_dependencies : Flag<["-"], "scan-dependencies">,
   HelpText<"Scan dependencies of the given Swift sources">, ModeOpt,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
 
-def emit_supported_features : Flag<["-"], "emit-supported-features">,
-  HelpText<"Emit a JSON file including all supported compiler features">, ModeOpt,
+def emit_supported_arguments : Flag<["-"], "emit-supported-arguments">,
+  HelpText<"Emit a JSON file including all supported compiler arguments">, ModeOpt,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
+def emit_supported_features : Flag<["-"], "emit-supported-features">,
+  HelpText<"This is a compatibility alias for '-emit-supported-arguments'">, ModeOpt,
+  Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild, HelpHidden]>,
+  Alias<emit_supported_arguments>;
 
 def enable_incremental_imports :
   Flag<["-"], "enable-incremental-imports">,
@@ -1676,6 +1701,18 @@ def disable_incremental_imports :
   HelpText<"Disable cross-module incremental build metadata and "
            "driver scheduling for Swift modules">;
 
+def enable_incremental_file_hashing :
+  Flag<["-"], "enable-incremental-file-hashing">,
+  Flags<[NewDriverOnlyOption]>,
+  HelpText<"Enable hashing of input and dependency file data "
+           "that can prevent unnecessary invalidation">;
+
+def disable_incremental_file_hashing :
+  Flag<["-"], "disable-incremental-file-hashing">,
+  Flags<[NewDriverOnlyOption]>,
+  HelpText<"Disable hashing of input and dependency file data "
+           "that can prevent unnecessary invalidation">;
+
 def index_file : Flag<["-"], "index-file">,
   HelpText<"Produce index data for a source file">, ModeOpt,
   Flags<[NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
@@ -1687,6 +1724,10 @@ def index_file_path : Separate<["-"], "index-file-path">,
 def index_store_path : Separate<["-"], "index-store-path">,
   Flags<[FrontendOption, ArgumentIsPath, CacheInvariant]>, MetaVarName<"<path>">,
   HelpText<"Store indexing data to <path>">;
+  
+def index_store_compress : Flag<["-"], "index-store-compress">,
+  Flags<[FrontendOption]>,
+  HelpText<"Compress the unit and record files in the index store">;
 
 def index_unit_output_path : Separate<["-"], "index-unit-output-path">,
   Flags<[FrontendOption, ArgumentIsPath, CacheInvariant]>, MetaVarName<"<path>">,
@@ -1769,11 +1810,34 @@ def emit_symbol_graph_dir : Separate<["-"], "emit-symbol-graph-dir">,
   HelpText<"Emit a symbol graph to directory <dir>">,
   MetaVarName<"<dir>">;
 
+def symbol_graph_pretty_print: Flag<["-"], "symbol-graph-pretty-print">,
+  Flags<[FrontendOption, NoInteractiveOption, HelpHidden, SupplementaryOutput]>,
+  HelpText<"Pretty-print the output symbol graph JSON">;
+
+def symbol_graph_skip_inherited_docs: Flag<["-"], "symbol-graph-skip-inherited-docs">,
+  Flags<[FrontendOption, NoInteractiveOption, HelpHidden, SupplementaryOutput]>,
+  HelpText<"Skip emitting doc comments for members inherited through classes or "
+           "default implementations">;
+
+def symbol_graph_skip_synthesized_members: Flag<["-"], "symbol-graph-skip-synthesized-members">,
+  Flags<[FrontendOption, NoInteractiveOption, HelpHidden, SupplementaryOutput]>,
+  HelpText<"Skip members inherited through classes or default implementations">;
+
 def symbol_graph_minimum_access_level: Separate<["-"], "symbol-graph-minimum-access-level">,
   Flags<[FrontendOption, NoInteractiveOption, SupplementaryOutput, HelpHidden]>,
   HelpText<"Include symbols with this access level or more when emitting a symbol graph">,
   MetaVarName<"<level>">;
 
+def symbol_graph_allow_availability_platforms: Separate<["-"], "symbol-graph-allow-availability-platforms">,
+  Flags<[FrontendOption, NoInteractiveOption, SupplementaryOutput, HelpHidden]>,
+  HelpText<"Restrict availability metadata to the given platforms, e.g. 'macOS,Swift'">,
+  MetaVarName<"<platforms>">;
+
+def symbol_graph_block_availability_platforms: Separate<["-"], "symbol-graph-block-availability-platforms">,
+  Flags<[FrontendOption, NoInteractiveOption, SupplementaryOutput, HelpHidden]>,
+  HelpText<"Remove the given platforms from symbol graph availability metadata, e.g. 'macOS,Swift'">,
+  MetaVarName<"<platforms>">;
+
 def pretty_print: Flag<["-"], "pretty-print">,
   Flags<[SwiftSymbolGraphExtractOption]>,
   HelpText<"Pretty-print the output JSON">;
@@ -1788,6 +1852,16 @@ def omit_extension_block_symbols: Flag<["-"], "omit-extension-block-symbols">,
         NoInteractiveOption, SupplementaryOutput, HelpHidden]>,
   HelpText<"Directly associate members and conformances with the extended nominal when generating symbol graphs instead of emitting 'swift.extension' symbols for extensions to external types">;
 
+def allow_availability_platforms: Separate<["-"], "allow-availability-platforms">,
+  Flags<[SwiftSymbolGraphExtractOption]>,
+  HelpText<"Restrict availability metadata to the given platforms, e.g. 'macOS,Swift'">,
+  MetaVarName<"<platforms>">;
+
+def block_availability_platforms: Separate<["-"], "block-availability-platforms">,
+  Flags<[SwiftSymbolGraphExtractOption]>,
+  HelpText<"Remove the given platforms from symbol graph availability metadata, e.g. 'macOS,Swift'">,
+  MetaVarName<"<platforms>">;
+
 // swift-synthesize-interface-only options
 def include_submodules : Flag<["-"], "include-submodules">,
   Flags<[NoDriverOption, SwiftSynthesizeInterfaceOption]>,
@@ -2077,6 +2151,13 @@ def emit_module_serialize_diagnostics_path:
            "<path>">,
   MetaVarName<"<path>">;
 
+def dependency_scan_serialize_diagnostics_path:
+  Separate<["-"], "dependency-scan-serialize-diagnostics-path">,
+  Flags<[ArgumentIsPath, SupplementaryOutput, NewDriverOnlyOption]>,
+  HelpText<"Emit a serialized diagnostics file for the dependency scanning task to "
+           "<path>">,
+  MetaVarName<"<path>">;
+
 def emit_module_dependencies_path:
   Separate<["-"], "emit-module-dependencies-path">,
   Flags<[ArgumentIsPath, SupplementaryOutput, NewDriverOnlyOption]>,
@@ -2194,8 +2275,12 @@ def sdk_module_cache_path : Separate<["-"], "sdk-module-cache-path">,
   Flags<[FrontendOption, DoesNotAffectIncrementalBuild, ArgumentIsPath]>,
   HelpText<"Specifies the module cache path for explicitly-built SDK modules">;
 
-def scanner_prefix_map : Separate<["-"], "scanner-prefix-map">,
+def scanner_prefix_map_paths : MultiArg<["-"], "scanner-prefix-map-paths", 2>,
   Flags<[FrontendOption, NewDriverOnlyOption]>,
+  HelpText<"Remap paths reported by dependency scanner">, MetaVarName<"<prefix> <replacement>">;
+
+def scanner_prefix_map : Separate<["-"], "scanner-prefix-map">,
+  Flags<[NewDriverOnlyOption]>,
   HelpText<"Remap paths reported by dependency scanner">, MetaVarName<"<prefix=replacement>">;
 
 def scanner_prefix_map_sdk : Separate<["-"], "scanner-prefix-map-sdk">,
@@ -2206,9 +2291,9 @@ def scanner_prefix_map_toolchain : Separate<["-"], "scanner-prefix-map-toolchain
   Flags<[NewDriverOnlyOption]>,
   HelpText<"Remap paths within toolchain directory reported by dependency scanner">, MetaVarName<"<path>">;
 
-def cache_replay_prefix_map: Separate<["-"], "cache-replay-prefix-map">,
+def cache_replay_prefix_map: MultiArg<["-"], "cache-replay-prefix-map", 2>,
   Flags<[FrontendOption, NoDriverOption, CacheInvariant]>,
-  HelpText<"Remap paths when replaying outputs from cache">, MetaVarName<"<prefix=replacement>">;
+  HelpText<"Remap paths when replaying outputs from cache">, MetaVarName<"<prefix> <replacement>">;
 
 // END ONLY SUPPORTED IN NEW DRIVER
 
@@ -2260,9 +2345,13 @@ def load_resolved_plugin:
   Flags<[FrontendOption, DoesNotAffectIncrementalBuild, ArgumentIsPath]>,
   HelpText<"Path to resolved plugin configuration and a comma-separated list "
            "of module names where the macro types are declared. Library path "
-           "and exectuable path can be empty if not used">,
+           "and executable path can be empty if not used">,
   MetaVarName<"<library-path>#<executable-path>#<module-names>">;
 
+def resolved_plugin_verification : Flag<["-"], "resolved-plugin-verification">,
+                                   Flags<[FrontendOption, NoDriverOption]>,
+                                   HelpText<"verify resolved plugins">;
+
 def in_process_plugin_server_path : Separate<["-"], "in-process-plugin-server-path">,
   Flags<[FrontendOption, ArgumentIsPath]>,
   HelpText<"Path to dynamic library plugin server">;
diff --git a/include/swift/Option/SanitizerOptions.h b/include/swift/Option/SanitizerOptions.h
index faa394f39b072..ab7f3bbdb8776 100644
--- a/include/swift/Option/SanitizerOptions.h
+++ b/include/swift/Option/SanitizerOptions.h
@@ -20,7 +20,7 @@
 #include "llvm/Option/ArgList.h"
 // FIXME: This include is just for llvm::SanitizerCoverageOptions. We should
 // split the header upstream so we don't include so much.
-#include "llvm/Transforms/Instrumentation.h"
+#include "llvm/Transforms/Utils/Instrumentation.h"
 
 namespace swift {
 class DiagnosticEngine;
diff --git a/include/swift/Parse/IDEInspectionCallbacks.h b/include/swift/Parse/IDEInspectionCallbacks.h
index 938083795af51..7147a5f945c5d 100644
--- a/include/swift/Parse/IDEInspectionCallbacks.h
+++ b/include/swift/Parse/IDEInspectionCallbacks.h
@@ -39,7 +39,9 @@ enum class ParameterizedDeclAttributeKind {
   Available,
   FreestandingMacro,
   AttachedMacro,
-  StorageRestrictions
+  StorageRestrictions,
+  InheritActorContext,
+  Nonexhaustive,
 };
 
 /// A bit of a hack. When completing inside the '@storageRestrictions'
@@ -254,6 +256,10 @@ class CodeCompletionCallbacks {
   virtual void
   completeImportDecl(ImportPath::Builder &Path) {};
 
+  /// Complete the 'using' decl with supported specifiers.
+  virtual void
+  completeUsingDecl() {};
+
   /// Complete unresolved members after dot.
   virtual void completeUnresolvedMember(CodeCompletionExpr *E,
                                         SourceLoc DotLoc) {};
diff --git a/include/swift/Parse/Lexer.h b/include/swift/Parse/Lexer.h
index a33e4d3bb3dd3..5390a059892d7 100644
--- a/include/swift/Parse/Lexer.h
+++ b/include/swift/Parse/Lexer.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -414,7 +414,7 @@ class Lexer {
   static bool isOperator(StringRef string);
 
   SourceLoc getLocForStartOfBuffer() const {
-    return SourceLoc(llvm::SMLoc::getFromPointer(BufferStart));
+    return SourceLoc::getFromPointer(BufferStart);
   }
   
   /// StringSegment - A segment of a (potentially interpolated) string.
@@ -516,7 +516,7 @@ class Lexer {
   }
 
   static SourceLoc getSourceLoc(const char *Loc) {
-    return SourceLoc(llvm::SMLoc::getFromPointer(Loc));
+    return SourceLoc::getFromPointer(Loc);
   }
 
   /// Get the token that starts at the given location.
diff --git a/include/swift/Parse/Parser.h b/include/swift/Parse/Parser.h
index f834cb84ce9b6..a930617945f5c 100644
--- a/include/swift/Parse/Parser.h
+++ b/include/swift/Parse/Parser.h
@@ -574,7 +574,11 @@ class Parser {
   /// the '(' by a space.
   ///
   /// If the next token is not '(' or it's on a new line, return false.
-  bool consumeIfAttributeLParen();
+  bool consumeIfAttributeLParen(bool isCustomAttr = false);
+
+  /// Check if the current token is '(' and it looks like a start of an
+  /// attribute argument list.
+  bool isAtAttributeLParen(bool isCustomAttr = false);
 
   bool consumeIfNotAtStartOfLine(tok K) {
     if (Tok.isAtStartOfLine()) return false;
@@ -690,6 +694,14 @@ class Parser {
     return Context.LangOpts.EnableExperimentalConcurrency;
   }
 
+  /// Returns true if a Swift declaration starts after the current token,
+  /// otherwise returns false.
+  bool isNextStartOfSwiftDecl() {
+    BacktrackingScope backtrack(*this);
+    consumeToken();
+    return isStartOfSwiftDecl();
+  }
+
 public:
   InFlightDiagnostic diagnose(SourceLoc Loc, DiagRef Diag) {
     if (Diags.isDiagnosticPointsToFirstBadToken(Diag.getID()) &&
@@ -1038,20 +1050,20 @@ class Parser {
                           bool isAttrModifier, SourceRange &parensRange,
                           llvm::function_ref<ParserStatus()> parseAttr);
 
-  /// Parse the @_specialize attribute.
+  /// Parse the @_specialize/@specialized attribute.
   /// \p closingBrace is the expected closing brace, which can be either ) or ]
   /// \p Attr is where to store the parsed attribute
   bool parseSpecializeAttribute(
-      swift::tok ClosingBrace, SourceLoc AtLoc, SourceLoc Loc,
-      SpecializeAttr *&Attr, AvailabilityRange *SILAvailability,
+      swift::tok ClosingBrace, SourceLoc AtLoc, SourceLoc Loc, bool isPublic,
+      AbstractSpecializeAttr *&Attr, AvailabilityRange *SILAvailability,
       llvm::function_ref<bool(Parser &)> parseSILTargetName =
           [](Parser &) { return false; },
       llvm::function_ref<bool(Parser &)> parseSILSIPModule =
           [](Parser &) { return false; });
 
-  /// Parse the arguments inside the @_specialize attribute
+  /// Parse the arguments inside the @_specialize/@specialized attribute
   bool parseSpecializeAttributeArguments(
-      swift::tok ClosingBrace, bool &DiscardAttribute,
+      swift::tok ClosingBrace, bool isPublic, bool &DiscardAttribute,
       std::optional<bool> &Exported,
       std::optional<SpecializeAttr::SpecializationKind> &Kind,
       TrailingWhereClause *&TrailingWhereClause, DeclNameRef &targetFunction,
@@ -1127,8 +1139,8 @@ class Parser {
   );
 
   /// Parse the @lifetime attribute.
-  ParserResult<LifetimeAttr> parseLifetimeAttribute(SourceLoc AtLoc,
-                                                    SourceLoc Loc);
+  ParserResult<LifetimeAttr>
+  parseLifetimeAttribute(StringRef attrName, SourceLoc atLoc, SourceLoc loc);
 
   /// Common utility to parse swift @lifetime decl attribute and SIL @lifetime
   /// type modifier.
@@ -1139,7 +1151,6 @@ class Parser {
                                   SourceLoc AtEndLoc,
                                   bool isFromClangAttribute = false);
 
-  bool isCustomAttributeArgument();
   bool canParseCustomAttribute();
 
   /// Parse a custom attribute after the initial '@'.
@@ -1158,7 +1169,8 @@ class Parser {
 
   bool isParameterSpecifier() {
     if (Tok.is(tok::kw_inout)) return true;
-    if (Context.LangOpts.hasFeature(Feature::LifetimeDependence) &&
+    if ((Context.LangOpts.hasFeature(Feature::LifetimeDependence) ||
+         Context.LangOpts.hasFeature(Feature::Lifetimes)) &&
         isSILLifetimeDependenceToken())
       return true;
     if (!canHaveParameterSpecifierContextualKeyword()) return false;
@@ -1169,8 +1181,9 @@ class Parser {
         Tok.isContextualKeyword("isolated") ||
         Tok.isContextualKeyword("_const"))
       return true;
-    if (Context.LangOpts.hasFeature(Feature::SendingArgsAndResults) &&
-        Tok.isContextualKeyword("sending"))
+    if (isCallerIsolatedSpecifier())
+      return true;
+    if (Tok.isContextualKeyword("sending"))
       return true;
     return false;
   }
@@ -1187,6 +1200,12 @@ class Parser {
            (peekToken().isContextualKeyword("lifetime"));
   }
 
+  bool isCallerIsolatedSpecifier() {
+    if (!Tok.isContextualKeyword("nonisolated"))
+      return false;
+    return peekToken().isFollowingLParen();
+  }
+
   bool canHaveParameterSpecifierContextualKeyword() {
     // The parameter specifiers like `isolated`, `consuming`, `borrowing` are
     // also valid identifiers and could be the name of a type. Check whether
@@ -1215,6 +1234,9 @@ class Parser {
   ParserResult<ImportDecl> parseDeclImport(ParseDeclOptions Flags,
                                            DeclAttributes &Attributes);
 
+  ParserResult<UsingDecl> parseDeclUsing(ParseDeclOptions Flags,
+                                         DeclAttributes &Attributes);
+
   /// Parse an inheritance clause into a vector of InheritedEntry's.
   ///
   /// \param allowClassRequirement whether to permit parsing of 'class'
@@ -1421,6 +1443,7 @@ class Parser {
     SourceLoc IsolatedLoc;
     SourceLoc ConstLoc;
     SourceLoc SendingLoc;
+    SourceLoc CallerIsolatedLoc;
     SmallVector<TypeOrCustomAttr> Attributes;
     LifetimeEntry *lifetimeEntry = nullptr;
 
@@ -1723,6 +1746,10 @@ class Parser {
   /// Returns true if a qualified declaration name base type can be parsed.
   bool canParseBaseTypeForQualifiedDeclName();
 
+  /// Returns true if `nonisolated` contextual keyword could be parsed
+  /// as part of the type a the current location.
+  bool canParseNonisolatedAsTypeModifier();
+
   /// Returns true if the current token is '->' or effects specifiers followed
   /// by '->'.
   ///
diff --git a/include/swift/Parse/Token.h b/include/swift/Parse/Token.h
index ba1a14a64ce30..39356dd252b06 100644
--- a/include/swift/Parse/Token.h
+++ b/include/swift/Parse/Token.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -19,7 +19,6 @@
 
 #include "swift/Basic/SourceLoc.h"
 #include "swift/Basic/LLVM.h"
-#include "swift/Parse/Token.h"
 #include "swift/Config.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -196,8 +195,9 @@ class Token {
 #define CONTEXTUAL_SIMPLE_DECL_ATTR(KW, ...) CONTEXTUAL_CASE(KW)
 #include "swift/AST/DeclAttr.def"
 #undef CONTEXTUAL_CASE
-      .Case("macro", true)
-      .Default(false);
+        .Case("macro", true)
+        .Case("using", true)
+        .Default(false);
   }
 
   bool isContextualPunctuator(StringRef ContextPunc) const {
@@ -266,6 +266,9 @@ class Token {
     }
   }
 
+  /// True if the token is an editor placeholder.
+  bool isEditorPlaceholder() const;
+
   /// True if the string literal token is multiline.
   bool isMultilineString() const {
     return MultilineString;
@@ -284,9 +287,7 @@ class Token {
   
   /// getLoc - Return a source location identifier for the specified
   /// offset in the current file.
-  SourceLoc getLoc() const {
-    return SourceLoc(llvm::SMLoc::getFromPointer(Text.begin()));
-  }
+  SourceLoc getLoc() const { return SourceLoc::getFromPointer(Text.begin()); }
 
   unsigned getLength() const { return Text.size(); }
 
@@ -300,17 +301,15 @@ class Token {
 
   CharSourceRange getCommentRange() const {
     if (CommentLength == 0)
-      return CharSourceRange(SourceLoc(llvm::SMLoc::getFromPointer(Text.begin())),
-                             0);
+      return CharSourceRange(SourceLoc::getFromPointer(Text.begin()), 0);
     auto TrimedComment = trimComment();
-    return CharSourceRange(
-      SourceLoc(llvm::SMLoc::getFromPointer(TrimedComment.begin())),
-      TrimedComment.size());
+    return CharSourceRange(SourceLoc::getFromPointer(TrimedComment.begin()),
+                           TrimedComment.size());
   }
   
   SourceLoc getCommentStart() const {
     if (CommentLength == 0) return SourceLoc();
-    return SourceLoc(llvm::SMLoc::getFromPointer(trimComment().begin()));
+    return SourceLoc::getFromPointer(trimComment().begin());
   }
 
   StringRef getRawText() const {
diff --git a/include/swift/PrintAsClang/ClangMacros.def b/include/swift/PrintAsClang/ClangMacros.def
index e62fbe039412c..48e614108c99b 100644
--- a/include/swift/PrintAsClang/ClangMacros.def
+++ b/include/swift/PrintAsClang/ClangMacros.def
@@ -176,24 +176,51 @@ CLANG_MACRO_CONDITIONAL("SWIFT_ENUM_ATTR", "(_extensibility)", \
                         "__attribute__((enum_extensibility(_extensibility)))")
 
 CLANG_MACRO_BODY("SWIFT_ENUM", \
-    "# define SWIFT_ENUM(_type, _name, _extensibility) " \
+    "# if (defined(__cplusplus) && __cplusplus >= 201103L) || " \
+    "     (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) || " \
+    "     __has_feature(objc_fixed_enum)\n" \
+    "#  define SWIFT_ENUM(_type, _name, _extensibility) " \
         "enum _name : _type _name; " \
         "enum SWIFT_ENUM_ATTR(_extensibility) SWIFT_ENUM_EXTRA _name : _type\n" \
-    "# if __has_feature(generalized_swift_name)\n" \
-    "#  define SWIFT_ENUM_NAMED(_type, _name, SWIFT_NAME, _extensibility) " \
-        "enum _name : _type _name SWIFT_COMPILE_NAME(SWIFT_NAME); " \
-        "enum SWIFT_COMPILE_NAME(SWIFT_NAME) SWIFT_ENUM_ATTR(_extensibility) " \
-            "SWIFT_ENUM_EXTRA _name : _type\n" \
+    "#  if __has_feature(generalized_swift_name)\n" \
+    "#   define SWIFT_ENUM_NAMED(_type, _name, SWIFT_NAME, _extensibility) " \
+         "enum _name : _type _name SWIFT_COMPILE_NAME(SWIFT_NAME); " \
+         "enum SWIFT_COMPILE_NAME(SWIFT_NAME) SWIFT_ENUM_ATTR(_extensibility) " \
+             "SWIFT_ENUM_EXTRA _name : _type\n" \
+    "#  else\n" \
+    "#   define SWIFT_ENUM_NAMED(_type, _name, SWIFT_NAME, _extensibility) " \
+         "SWIFT_ENUM(_type, _name, _extensibility)\n" \
+    "#  endif\n" \
     "# else\n" \
+    "#  define SWIFT_ENUM(_type, _name, _extensibility) _type _name; enum \n" \
     "#  define SWIFT_ENUM_NAMED(_type, _name, SWIFT_NAME, _extensibility) " \
         "SWIFT_ENUM(_type, _name, _extensibility)\n" \
     "# endif")
 CLANG_MACRO_DEFINED("SWIFT_ENUM_NAMED")
 
+CLANG_MACRO_BODY("SWIFT_ENUM_TAG", \
+    "# if (defined(__cplusplus) && __cplusplus >= 201103L) || " \
+    "     (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) || " \
+    "     __has_feature(objc_fixed_enum)\n" \
+    "#  define SWIFT_ENUM_TAG enum\n" \
+    "# else\n" \
+    "#  define SWIFT_ENUM_TAG\n" \
+    "# endif")
+
+CLANG_MACRO_BODY("SWIFT_ENUM_FWD_DECL", \
+    "# if (defined(__cplusplus) && __cplusplus >= 201103L) || " \
+    "     (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) || " \
+    "     __has_feature(objc_fixed_enum)\n" \
+    "#  define SWIFT_ENUM_FWD_DECL(_type, _name) enum _name : _type _name;\n" \
+    "# else\n" \
+    "#  define SWIFT_ENUM_FWD_DECL(_type, _name) _type _name;\n" \
+    "# endif")
+
 CLANG_MACRO("SWIFT_UNAVAILABLE", , "__attribute__((unavailable))")
 CLANG_MACRO("SWIFT_UNAVAILABLE_MSG", "(msg)", "__attribute__((unavailable(msg)))")
 
 CLANG_MACRO("SWIFT_AVAILABILITY", "(plat, ...)", "__attribute__((availability(plat, __VA_ARGS__)))")
+CLANG_MACRO("SWIFT_AVAILABILITY_DOMAIN", "(dom, ...)", "__attribute__((availability(domain: dom, __VA_ARGS__)))")
 
 CLANG_MACRO("SWIFT_WEAK_IMPORT", , "__attribute__((weak_import))")
 
diff --git a/include/swift/Remote/CMemoryReader.h b/include/swift/Remote/CMemoryReader.h
index 3805b76c7cdad..2a469bb80757b 100644
--- a/include/swift/Remote/CMemoryReader.h
+++ b/include/swift/Remote/CMemoryReader.h
@@ -42,39 +42,16 @@ namespace remote {
 class CMemoryReader final : public MemoryReader {
   MemoryReaderImpl Impl;
 
-  uint64_t ptrauthMask;
-
-  uint64_t getPtrauthMask() {
-    if (ptrauthMask == 0) {
-      int success;
-      if (Impl.PointerSize == 4) {
-        uint32_t ptrauthMask32 = 0;
-        success = queryDataLayout(DataLayoutQueryType::DLQ_GetPtrAuthMask,
-                                  nullptr, &ptrauthMask32);
-        ptrauthMask = ptrauthMask32;
-      } else if (Impl.PointerSize == 8) {
-        success = queryDataLayout(DataLayoutQueryType::DLQ_GetPtrAuthMask,
-                                  nullptr, &ptrauthMask);
-      } else {
-        success = 0;
-      }
-
-      if (!success)
-        ptrauthMask = ~0ull;
-    }
-    return ptrauthMask;
-  }
-
   // Check to see if an address has bits outside the ptrauth mask. This suggests
   // that we're likely failing to strip a signed pointer when reading from it.
   bool hasSignatureBits(RemoteAddress address) {
-    return false;
-    uint64_t addressData = address.getAddressData();
-    return addressData != (addressData & getPtrauthMask());
+    uint64_t addressData = address.getRawAddress();
+    uint64_t mask = getPtrAuthMask().value_or(~uint64_t(0));
+    return addressData != (addressData & mask);
   }
 
 public:
-  CMemoryReader(MemoryReaderImpl Impl) : Impl(Impl), ptrauthMask(0) {
+  CMemoryReader(MemoryReaderImpl Impl) : Impl(Impl) {
     assert(this->Impl.queryDataLayout && "No queryDataLayout implementation");
     assert(this->Impl.getStringLength && "No stringLength implementation");
     assert(this->Impl.readBytes && "No readBytes implementation");
@@ -89,13 +66,12 @@ class CMemoryReader final : public MemoryReader {
   RemoteAddress getSymbolAddress(const std::string &name) override {
     auto addressData = Impl.getSymbolAddress(Impl.reader_context,
                                              name.c_str(), name.size());
-    return RemoteAddress(addressData);
+    return RemoteAddress(addressData, RemoteAddress::DefaultAddressSpace);
   }
 
   uint64_t getStringLength(RemoteAddress address) {
     assert(!hasSignatureBits(address));
-    return Impl.getStringLength(Impl.reader_context,
-                                address.getAddressData());
+    return Impl.getStringLength(Impl.reader_context, address.getRawAddress());
   }
 
   bool readString(RemoteAddress address, std::string &dest) override {
@@ -120,7 +96,7 @@ class CMemoryReader final : public MemoryReader {
   ReadBytesResult readBytes(RemoteAddress address, uint64_t size) override {
     assert(!hasSignatureBits(address));
     void *FreeContext;
-    auto Ptr = Impl.readBytes(Impl.reader_context, address.getAddressData(),
+    auto Ptr = Impl.readBytes(Impl.reader_context, address.getRawAddress(),
                               size, &FreeContext);
 
     auto Free = Impl.free;
@@ -134,8 +110,7 @@ class CMemoryReader final : public MemoryReader {
     return ReadBytesResult(Ptr, freeLambda);
   }
 };
-
-}
-}
+} // namespace remote
+} // namespace swift
 
 #endif
diff --git a/include/swift/Remote/Failure.h b/include/swift/Remote/Failure.h
index 908e6357c0261..916c74892928d 100644
--- a/include/swift/Remote/Failure.h
+++ b/include/swift/Remote/Failure.h
@@ -288,7 +288,7 @@ class Failure {
       case ArgStorageKind::Address: {
         result += '0';
         result += 'x';
-        uint64_t address = Args[argIndex].Address.getAddressData();
+        uint64_t address = Args[argIndex].Address.getRawAddress();
         unsigned max = ((address >> 32) != 0 ? 16 : 8);
         for (unsigned i = 0; i != max; ++i) {
           result += "0123456789abcdef"[(address >> (max - 1 - i) * 4) & 0xF];
diff --git a/include/swift/Remote/InProcessMemoryReader.h b/include/swift/Remote/InProcessMemoryReader.h
index 9fa78a28308d6..dbe7351317a62 100644
--- a/include/swift/Remote/InProcessMemoryReader.h
+++ b/include/swift/Remote/InProcessMemoryReader.h
@@ -105,8 +105,8 @@ class InProcessMemoryReader final : public MemoryReader {
     return ReadBytesResult(address.getLocalPointer<void>(), [](const void *) {});
   }
 };
- 
-}
-}
+
+} // namespace remote
+} // namespace swift
 
 #endif
diff --git a/include/swift/Remote/MemoryReader.h b/include/swift/Remote/MemoryReader.h
index 1008650b43990..835ea59b93b6c 100644
--- a/include/swift/Remote/MemoryReader.h
+++ b/include/swift/Remote/MemoryReader.h
@@ -22,6 +22,7 @@
 #include "swift/SwiftRemoteMirror/MemoryReaderInterface.h"
 #include <optional>
 
+#include <cstdint>
 #include <cstdlib>
 #include <cstring>
 #include <functional>
@@ -37,7 +38,80 @@ namespace remote {
 /// This abstraction presents memory as if it were a read-only
 /// representation of the address space of a remote process.
 class MemoryReader {
+  uint8_t cachedPointerSize = 0;
+  uint8_t cachedSizeSize = 0;
+  uint64_t cachedPtrAuthMask = 0;
+  uint8_t cachedObjCReservedLowBits = 0xff;
+  uint64_t cachedLeastValidPointerValue = 0;
+  uint8_t cachedObjCInteropIsEnabled = 0xff;
+
+protected:
+  virtual bool queryDataLayout(DataLayoutQueryType type, void *inBuffer,
+                               void *outBuffer) = 0;
+
 public:
+  std::optional<uint8_t> getPointerSize() {
+    if (cachedPointerSize == 0) {
+      if (!queryDataLayout(DLQ_GetPointerSize, nullptr, &cachedPointerSize))
+        return std::nullopt;
+    }
+    return cachedPointerSize;
+  }
+
+  std::optional<uint8_t> getSizeSize() {
+    if (cachedSizeSize == 0) {
+      if (!queryDataLayout(DLQ_GetSizeSize, nullptr, &cachedSizeSize))
+        return std::nullopt;
+    }
+    return cachedSizeSize;
+  }
+
+  std::optional<uint64_t> getPtrAuthMask() {
+    if (cachedPtrAuthMask == 0) {
+      auto ptrSize = getPointerSize();
+      if (!ptrSize)
+        return std::nullopt;
+
+      if (ptrSize.value() == sizeof(uint64_t)) {
+        if (!queryDataLayout(DLQ_GetPtrAuthMask, nullptr, &cachedPtrAuthMask))
+          return std::nullopt;
+      } else if (ptrSize.value() == sizeof(uint32_t)) {
+        uint32_t mask;
+        if (!queryDataLayout(DLQ_GetPtrAuthMask, nullptr, &mask))
+          return std::nullopt;
+        cachedPtrAuthMask = mask;
+      }
+    }
+    return cachedPtrAuthMask;
+  }
+
+  std::optional<uint8_t> getObjCReservedLowBits() {
+    if (cachedObjCReservedLowBits == 0xff) {
+      if (!queryDataLayout(DLQ_GetObjCReservedLowBits, nullptr,
+                           &cachedObjCReservedLowBits))
+        return std::nullopt;
+    }
+    return cachedObjCReservedLowBits;
+  }
+
+  std::optional<uint64_t> getLeastValidPointerValue() {
+    if (cachedLeastValidPointerValue == 0) {
+      if (!queryDataLayout(DLQ_GetLeastValidPointerValue, nullptr,
+                           &cachedLeastValidPointerValue))
+        return std::nullopt;
+    }
+    return cachedLeastValidPointerValue;
+  }
+
+  std::optional<bool> getObjCInteropIsEnabled() {
+    if (cachedObjCInteropIsEnabled == 0xff) {
+      if (!queryDataLayout(DLQ_GetObjCInteropIsEnabled, nullptr,
+                           &cachedObjCInteropIsEnabled))
+        return std::nullopt;
+    }
+    return cachedObjCInteropIsEnabled;
+  }
+
   /// A convenient name for the return type from readBytes.
   using ReadBytesResult =
       std::unique_ptr<const void, std::function<void(const void *)>>;
@@ -46,9 +120,6 @@ class MemoryReader {
   using ReadObjResult =
       std::unique_ptr<const T, std::function<void(const void *)>>;
 
-  virtual bool queryDataLayout(DataLayoutQueryType type, void *inBuffer,
-                               void *outBuffer) = 0;
-
   /// Look up the given public symbol name in the remote process.
   virtual RemoteAddress getSymbolAddress(const std::string &name) = 0;
 
@@ -57,13 +128,29 @@ class MemoryReader {
   ///
   /// Returns false if the operation failed.
   virtual bool readString(RemoteAddress address, std::string &dest) = 0;
-  
+
+  /// Attempts to read a remote address from the given address in the remote
+  /// process.
+  ///
+  /// Returns false if the operator failed.
+  template <typename IntegerType>
+  bool readRemoteAddress(RemoteAddress address, RemoteAddress &out) {
+    constexpr std::size_t integerSize = sizeof(IntegerType);
+    static_assert((integerSize == 4 || integerSize == 8) &&
+                  "Only 32 or 64 bit architectures are supported!");
+    return readRemoteAddressImpl(address, out, integerSize);
+  }
+
   /// Attempts to read an integer from the given address in the remote
   /// process.
   ///
   /// Returns false if the operation failed.
   template <typename IntegerType>
   bool readInteger(RemoteAddress address, IntegerType *dest) {
+    static_assert(!std::is_same<RemoteAddress, IntegerType>(),
+                  "RemoteAddress cannot be read in directly, use "
+                  "readRemoteAddress instead.");
+
     return readBytes(address, reinterpret_cast<uint8_t*>(dest),
                      sizeof(IntegerType));
   }
@@ -147,7 +234,15 @@ class MemoryReader {
   virtual RemoteAbsolutePointer resolvePointer(RemoteAddress address,
                                                uint64_t readValue) {
     // Default implementation returns the read value as is.
-    return RemoteAbsolutePointer("", readValue);
+    return RemoteAbsolutePointer(
+        RemoteAddress(readValue, address.getAddressSpace()));
+  }
+
+  /// Performs the inverse operation of \ref resolvePointer.
+  /// A use-case for this is to turn file addresses into in-process addresses.
+  virtual std::optional<RemoteAddress>
+  resolveRemoteAddress(RemoteAddress address) const {
+    return std::nullopt;
   }
 
   virtual std::optional<RemoteAbsolutePointer>
@@ -159,7 +254,7 @@ class MemoryReader {
   virtual RemoteAbsolutePointer getSymbol(RemoteAddress address) {
     if (auto symbol = resolvePointerAsSymbol(address))
       return *symbol;
-    return RemoteAbsolutePointer("", address.getAddressData());
+    return RemoteAbsolutePointer(address);
   }
 
   /// Lookup a dynamic symbol name (ie dynamic loader binding) for the given
@@ -202,50 +297,37 @@ class MemoryReader {
   // index (counting from 0).
   bool readHeapObjectExtraInhabitantIndex(RemoteAddress address,
                                           int *extraInhabitantIndex) {
-    uint8_t PointerSize;
-    if (!queryDataLayout(DataLayoutQueryType::DLQ_GetPointerSize,
-                         nullptr, &PointerSize)) {
-      return false;
-    }
-    uint64_t LeastValidPointerValue;
-    if (!queryDataLayout(DataLayoutQueryType::DLQ_GetLeastValidPointerValue,
-                         nullptr, &LeastValidPointerValue)) {
-      return false;
-    }
-    uint8_t ObjCReservedLowBits;
-    if (!queryDataLayout(DataLayoutQueryType::DLQ_GetObjCReservedLowBits,
-                         nullptr, &ObjCReservedLowBits)) {
+    auto PointerSize = getPointerSize();
+    auto LeastValidPointerValue = getLeastValidPointerValue();
+    auto ObjCReservedLowBits = getObjCReservedLowBits();
+
+    if (!PointerSize || !LeastValidPointerValue || !ObjCReservedLowBits)
       return false;
-    }
+
     uint64_t RawPointerValue;
-    if (!readInteger(address, PointerSize, &RawPointerValue)) {
+    if (!readInteger(address, PointerSize.value(), &RawPointerValue)) {
       return false;
     }
-    if (RawPointerValue >= LeastValidPointerValue) {
+    if (RawPointerValue >= LeastValidPointerValue.value()) {
       *extraInhabitantIndex = -1; // Valid value, not an XI
     } else {
-      *extraInhabitantIndex = (RawPointerValue >> ObjCReservedLowBits);
+      *extraInhabitantIndex = (RawPointerValue >> ObjCReservedLowBits.value());
     }
     return true;
   }
 
   bool readFunctionPointerExtraInhabitantIndex(RemoteAddress address,
                                                int *extraInhabitantIndex) {
-    uint8_t PointerSize;
-    if (!queryDataLayout(DataLayoutQueryType::DLQ_GetPointerSize,
-                         nullptr, &PointerSize)) {
+    auto PointerSize = getPointerSize();
+    auto LeastValidPointerValue = getLeastValidPointerValue();
+    if (!PointerSize || !LeastValidPointerValue)
       return false;
-    }
-    uint64_t LeastValidPointerValue;
-    if (!queryDataLayout(DataLayoutQueryType::DLQ_GetLeastValidPointerValue,
-                         nullptr, &LeastValidPointerValue)) {
-      return false;
-    }
+
     uint64_t RawPointerValue;
-    if (!readInteger(address, PointerSize, &RawPointerValue)) {
+    if (!readInteger(address, PointerSize.value(), &RawPointerValue)) {
       return false;
     }
-    if (RawPointerValue >= LeastValidPointerValue) {
+    if (RawPointerValue >= LeastValidPointerValue.value()) {
       *extraInhabitantIndex = -1; // Valid value, not an XI
     } else {
       *extraInhabitantIndex = RawPointerValue;
@@ -254,9 +336,38 @@ class MemoryReader {
   }
 
   virtual ~MemoryReader() = default;
+
+protected:
+  /// Implementation detail of remoteRemoteAddress. This exists because
+  /// templated functions cannot be virtual.
+  ///
+  /// Attempts to read a remote address of a given size from the given address
+  /// in the remote process.
+  ///
+  /// Returns false if the operator failed.
+  virtual bool readRemoteAddressImpl(RemoteAddress address, RemoteAddress &out,
+                                     std::size_t integerSize) {
+    assert((integerSize == 4 || integerSize == 8) &&
+           "Only 32 or 64 bit architectures are supported!");
+    if (integerSize == 4) {
+      uint32_t buf;
+      if (!readBytes(address, reinterpret_cast<uint8_t *>(&buf), integerSize))
+        return false;
+      out = RemoteAddress(buf, address.getAddressSpace());
+      return true;
+    }
+    if (integerSize == 8) {
+      uint64_t buf;
+      if (!readBytes(address, reinterpret_cast<uint8_t *>(&buf), integerSize))
+        return false;
+      out = RemoteAddress(buf, address.getAddressSpace());
+      return true;
+    }
+    return false;
+  }
 };
 
-} // end namespace reflection
+} // end namespace remote
 } // end namespace swift
 
 #endif // SWIFT_REFLECTION_READER_H
diff --git a/include/swift/Remote/MetadataReader.h b/include/swift/Remote/MetadataReader.h
index 262368e9f4a2b..9187685f49b3b 100644
--- a/include/swift/Remote/MetadataReader.h
+++ b/include/swift/Remote/MetadataReader.h
@@ -58,19 +58,17 @@ enum class MangledNameKind {
 template <typename T>
 class RemoteRef {
 private:
-  uint64_t Address;
+  RemoteAddress Address;
   const T *LocalBuffer;
 
 public:
-  RemoteRef()
-    : Address(0), LocalBuffer(nullptr) {}
+  RemoteRef() : Address(), LocalBuffer(nullptr) {}
 
   /*implicit*/
   RemoteRef(std::nullptr_t _) : RemoteRef() {}
 
-  template<typename StoredPointer>
-  explicit RemoteRef(StoredPointer address, const T *localBuffer)
-    : Address((uint64_t)address), LocalBuffer(localBuffer) {}
+  explicit RemoteRef(RemoteAddress address, const T *localBuffer)
+      : Address(address), LocalBuffer(localBuffer) {}
 
   // <rdar://99715218> Some versions of clang++ sometimes fail to generate the
   // copy constructor for this type correctly - add a workaround
@@ -83,9 +81,7 @@ class RemoteRef {
     return *this;
   }
 
-  uint64_t getAddressData() const {
-    return Address;
-  }
+  RemoteAddress getRemoteAddress() const { return Address; }
 
   const T *getLocalBuffer() const {
     return LocalBuffer;
@@ -113,23 +109,23 @@ class RemoteRef {
   template<typename U>
   RemoteRef<U> getField(U &field) const {
     auto offset = (intptr_t)&field - (intptr_t)LocalBuffer;
-    return RemoteRef<U>((uint64_t)(Address + (int64_t)offset), &field);
+    return RemoteRef<U>((Address + (int64_t)offset), &field);
   }
   
   /// Resolve the remote address of a relative offset stored at the remote address.
-  uint64_t resolveRelativeAddressData() const {
+  RemoteAddress resolveRelativeAddressData() const {
     int32_t offset;
     memcpy(&offset, LocalBuffer, sizeof(int32_t));
     if (offset == 0)
-      return 0;
+      return RemoteAddress();
     return Address + (int64_t)offset;
   }
-  
-  template<typename U>
-  uint64_t resolveRelativeFieldData(U &field) const {
+
+  template <typename U>
+  RemoteAddress resolveRelativeFieldData(U &field) const {
     return getField(field).resolveRelativeAddressData();
   }
-  
+
   RemoteRef atByteOffset(int64_t Offset) const {
     return RemoteRef(Address + Offset,
                      (const T *)((intptr_t)LocalBuffer + Offset));
@@ -195,10 +191,10 @@ class MetadataReader {
   /// amounts of data when we encounter corrupt values for sizes/counts.
   static const uint64_t MaxMetadataSize = 1048576; // 1MB
 
-  /// The dense map info for a std::pair<StoredPointer, bool>.
+  /// The dense map info for a std::pair<RemoteAddress, bool>.
   struct DenseMapInfoTypeCacheKey {
-    using Pair = std::pair<StoredPointer, bool>;
-    using StoredPointerInfo = llvm::DenseMapInfo<StoredPointer>;
+    using Pair = std::pair<RemoteAddress, bool>;
+    using StoredPointerInfo = llvm::DenseMapInfo<RemoteAddress>;
 
     static inline Pair getEmptyKey() {
       // Since bool doesn't have an empty key implementation, we only use the
@@ -223,7 +219,7 @@ class MetadataReader {
 
   /// A cache of built types, keyed by the address of the type and whether the
   /// request ignored articial superclasses or not.
-  llvm::DenseMap<std::pair<StoredPointer, bool>, BuiltType,
+  llvm::DenseMap<std::pair<RemoteAddress, bool>, BuiltType,
                  DenseMapInfoTypeCacheKey>
       TypeCache;
 
@@ -231,7 +227,7 @@ class MetadataReader {
   using OwnedMetadataRef = MemoryReader::ReadBytesResult;
 
   /// A cache of read type metadata, keyed by the address of the metadata.
-  llvm::DenseMap<StoredPointer, OwnedMetadataRef> MetadataCache;
+  llvm::DenseMap<RemoteAddress, OwnedMetadataRef> MetadataCache;
 
   using ContextDescriptorRef =
       RemoteRef<const TargetContextDescriptor<Runtime>>;
@@ -313,14 +309,14 @@ class MetadataReader {
 
   /// A cache of read nominal type descriptors, keyed by the address of the
   /// nominal type descriptor.
-  llvm::DenseMap<StoredPointer, OwnedContextDescriptorRef>
+  llvm::DenseMap<RemoteAddress, OwnedContextDescriptorRef>
       ContextDescriptorCache;
 
   using OwnedProtocolDescriptorRef =
     std::unique_ptr<const TargetProtocolDescriptor<Runtime>, delete_with_free>;
   /// A cache of read extended existential shape metadata, keyed by the
   /// address of the shape metadata.
-  llvm::DenseMap<StoredPointer, OwnedShapeRef> ShapeCache;
+  llvm::DenseMap<RemoteAddress, OwnedShapeRef> ShapeCache;
 
   enum class IsaEncodingKind {
     /// We haven't checked yet.
@@ -359,8 +355,8 @@ class MetadataReader {
   StoredPointer IsaIndexShift;
   StoredPointer IsaMagicMask;
   StoredPointer IsaMagicValue;
-  StoredPointer IndexedClassesPointer;
-  StoredPointer IndexedClassesCountPointer;
+  RemoteAddress IndexedClassesPointer;
+  RemoteAddress IndexedClassesCountPointer;
   StoredPointer LastIndexedClassesCount = 0;
 
   enum class TaggedPointerEncodingKind {
@@ -389,11 +385,11 @@ class MetadataReader {
   StoredPointer TaggedPointerMask;
   StoredPointer TaggedPointerSlotShift;
   StoredPointer TaggedPointerSlotMask;
-  StoredPointer TaggedPointerClasses;
+  RemoteAddress TaggedPointerClasses;
   StoredPointer TaggedPointerExtendedMask;
   StoredPointer TaggedPointerExtendedSlotShift;
   StoredPointer TaggedPointerExtendedSlotMask;
-  StoredPointer TaggedPointerExtendedClasses;
+  RemoteAddress TaggedPointerExtendedClasses;
   StoredPointer TaggedPointerObfuscator;
 
   Demangle::NodeFactory Factory;
@@ -411,33 +407,32 @@ class MetadataReader {
 
   StoredPointer PtrAuthMask;
 
-  StoredPointer stripSignedPointer(StoredSignedPointer P) {
-    return P.SignedValue & PtrAuthMask;
+  RemoteAddress stripSignedPointer(RemoteAddress P) {
+    // Only pointers in the default address space are signed.
+    if (P.getAddressSpace() == RemoteAddress::DefaultAddressSpace)
+      return P & PtrAuthMask;
+    return P;
+  }
+
+  RemoteAddress stripSignedPointer(StoredSignedPointer P) {
+    return RemoteAddress(P.SignedValue & PtrAuthMask,
+                         RemoteAddress::DefaultAddressSpace);
   }
 
   RemoteAbsolutePointer stripSignedPointer(const RemoteAbsolutePointer &P) {
-    if (P.isResolved()) {
-      return RemoteAbsolutePointer("", 
-        P.getResolvedAddress().getAddressData() & PtrAuthMask);
-    }
-    return P;
+    auto Stripped = stripSignedPointer(P.getResolvedAddress());
+    return RemoteAbsolutePointer(P.getSymbol(), P.getOffset(), Stripped);
   }
 
   StoredPointer queryPtrAuthMask() {
-    StoredPointer QueryResult;
-    if (Reader->queryDataLayout(DataLayoutQueryType::DLQ_GetPtrAuthMask,
-                                nullptr, &QueryResult)) {
-      return QueryResult;
-    }
-    return ~StoredPointer(0);
+    auto QueryResult = Reader->getPtrAuthMask();
+    return QueryResult.value_or(~StoredPointer(0));
   }
 
   template <class... T>
-  MetadataReader(std::shared_ptr<MemoryReader> reader, T &&... args)
-    : Builder(std::forward<T>(args)...),
-      Reader(std::move(reader)),
-      PtrAuthMask(queryPtrAuthMask()) {
-  }
+  MetadataReader(std::shared_ptr<MemoryReader> reader, T &&...args)
+      : Builder(std::forward<T>(args)...), Reader(std::move(reader)),
+        PtrAuthMask(queryPtrAuthMask()) {}
 
   MetadataReader(const MetadataReader &other) = delete;
   MetadataReader &operator=(const MetadataReader &other) = delete;
@@ -464,7 +459,7 @@ class MetadataReader {
       auto offsetInMangledName =
             (const char *)base - mangledName.getLocalBuffer();
       auto remoteAddress =
-        mangledName.getAddressData() + offsetInMangledName + offset;
+          mangledName.getRemoteAddress() + offsetInMangledName + offset;
 
       RemoteAbsolutePointer resolved;
       if (directness == Directness::Indirect) {
@@ -474,7 +469,7 @@ class MetadataReader {
           return nullptr;
         }
       } else {
-        resolved = Reader->getSymbol(RemoteAddress(remoteAddress));
+        resolved = Reader->getSymbol(remoteAddress);
       }
 
       switch (kind) {
@@ -485,12 +480,13 @@ class MetadataReader {
         // Try to preserve a reference to an OpaqueTypeDescriptor
         // symbolically, since we'd like to read out and resolve the type ref
         // to the underlying type if available.
-        if (useOpaqueTypeSymbolicReferences
-           && context.isResolved()
-           && context.getResolved()->getKind() == ContextDescriptorKind::OpaqueType){
+        if (useOpaqueTypeSymbolicReferences && context.isResolved() &&
+            context.getResolved()->getKind() ==
+                ContextDescriptorKind::OpaqueType) {
           return dem.createNode(
-                            Node::Kind::OpaqueTypeDescriptorSymbolicReference,
-                            context.getResolved().getAddressData());
+              Node::Kind::OpaqueTypeDescriptorSymbolicReference,
+              context.getResolved().getRemoteAddress().getRawAddress(),
+              context.getResolved().getRemoteAddress().getAddressSpace());
         }
 
         return buildContextMangling(context, dem);
@@ -504,43 +500,28 @@ class MetadataReader {
         // The symbolic reference points at a unique extended
         // existential type shape.
         return dem.createNode(
-                          Node::Kind::UniqueExtendedExistentialTypeShapeSymbolicReference,
-                          resolved.getResolvedAddress().getAddressData());
+            Node::Kind::UniqueExtendedExistentialTypeShapeSymbolicReference,
+            resolved.getResolvedAddress().getRawAddress(),
+            resolved.getResolvedAddress().getAddressSpace());
       }
       case Demangle::SymbolicReferenceKind::NonUniqueExtendedExistentialTypeShape: {
         // The symbolic reference points at a non-unique extended
         // existential type shape.
         return dem.createNode(
-                          Node::Kind::NonUniqueExtendedExistentialTypeShapeSymbolicReference,
-                          resolved.getResolvedAddress().getAddressData());
+            Node::Kind::NonUniqueExtendedExistentialTypeShapeSymbolicReference,
+            resolved.getResolvedAddress().getRawAddress(),
+            resolved.getResolvedAddress().getAddressSpace());
       }
       case Demangle::SymbolicReferenceKind::ObjectiveCProtocol: {
         // 'resolved' points to a struct of two relative addresses.
         // The second entry is a relative address to the mangled protocol
         // without symbolic references.
 
-        // lldb might return an unresolved remote absolute pointer from its
-        // resolvePointerAsSymbol implementation -- workaround this.
-        if (!resolved.isResolved()) {
-          auto remoteAddr = RemoteAddress(remoteAddress);
-          resolved =
-            RemoteAbsolutePointer("", remoteAddr.getAddressData());
-        }
-
-        auto addr =
-            resolved.getResolvedAddress().getAddressData() + sizeof(int32_t);
+        auto addr = resolved.getResolvedAddress() + sizeof(int32_t);
         int32_t offset;
-        Reader->readInteger(RemoteAddress(addr), &offset);
+        Reader->readInteger(addr, &offset);
         auto addrOfTypeRef = addr + offset;
-        resolved = Reader->getSymbol(RemoteAddress(addrOfTypeRef));
-
-        // lldb might return an unresolved remote absolute pointer from its
-        // resolvePointerAsSymbol implementation -- workaround this.
-        if (!resolved.isResolved()) {
-          auto remoteAddr = RemoteAddress(addrOfTypeRef);
-          resolved =
-            RemoteAbsolutePointer("", remoteAddr.getAddressData());
-        }
+        resolved = Reader->getSymbol(addrOfTypeRef);
 
         // Dig out the protocol from the protocol list.
         auto protocolList = readMangledName(resolved.getResolvedAddress(),
@@ -594,10 +575,9 @@ class MetadataReader {
   /// Demangle a mangled name from a potentially temporary std::string. The
   /// demangler may produce pointers into the string data, so this copies the
   /// string into the demangler's allocation first.
-  Demangle::NodePointer demangle(uint64_t remoteAddress,
+  Demangle::NodePointer demangle(RemoteAddress remoteAddress,
                                  const std::string &mangledName,
-                                 MangledNameKind kind,
-                                 Demangler &dem) {
+                                 MangledNameKind kind, Demangler &dem) {
     StringRef mangledNameCopy = dem.copyString(mangledName);
     return demangle(RemoteRef<char>(remoteAddress, mangledNameCopy.data()),
                     kind, dem);
@@ -625,7 +605,7 @@ class MetadataReader {
 
   /// Given a remote pointer to metadata, attempt to discover its MetadataKind.
   std::optional<MetadataKind>
-  readKindFromMetadata(StoredPointer MetadataAddress) {
+  readKindFromMetadata(RemoteAddress MetadataAddress) {
     auto meta = readMetadata(MetadataAddress);
     if (!meta)
       return std::nullopt;
@@ -634,11 +614,10 @@ class MetadataReader {
   }
 
   /// Given a remote pointer to class metadata, attempt to read its superclass.
-  StoredPointer
-  readSuperClassFromClassMetadata(StoredPointer MetadataAddress) {
+  RemoteAddress readSuperClassFromClassMetadata(RemoteAddress MetadataAddress) {
     auto meta = readMetadata(MetadataAddress);
     if (!meta || meta->getKind() != MetadataKind::Class)
-      return StoredPointer();
+      return RemoteAddress();
 
     auto classMeta = cast<TargetClassMetadata>(meta);
     return stripSignedPointer(classMeta->Superclass);
@@ -647,7 +626,7 @@ class MetadataReader {
   /// Given a remote pointer to class metadata, attempt to discover its class
   /// instance size and whether fields should use the resilient layout strategy.
   std::optional<unsigned>
-  readInstanceStartFromClassMetadata(StoredPointer MetadataAddress) {
+  readInstanceStartFromClassMetadata(RemoteAddress MetadataAddress) {
     auto meta = readMetadata(MetadataAddress);
     if (!meta || meta->getKind() != MetadataKind::Class)
       return std::nullopt;
@@ -656,7 +635,7 @@ class MetadataReader {
       // The following algorithm only works on the non-fragile Apple runtime.
 
       // Grab the RO-data pointer.  This part is not ABI.
-      StoredPointer roDataPtr = readObjCRODataPtr(MetadataAddress);
+      RemoteAddress roDataPtr = readObjCRODataPtr(MetadataAddress);
       if (!roDataPtr)
         return std::nullopt;
 
@@ -664,7 +643,7 @@ class MetadataReader {
       auto address = roDataPtr + sizeof(uint32_t) * 1;
 
       unsigned start;
-      if (!Reader->readInteger(RemoteAddress(address), &start))
+      if (!Reader->readInteger(address, &start))
         return std::nullopt;
 
       return start;
@@ -694,19 +673,19 @@ class MetadataReader {
   /// witness table. Note that it's not safe to access any non-mandatory
   /// members of the value witness table, like extra inhabitants or enum members.
   std::optional<TargetValueWitnessTable<Runtime>>
-  readValueWitnessTable(StoredPointer MetadataAddress) {
+  readValueWitnessTable(RemoteAddress MetadataAddress) {
     // The value witness table pointer is at offset -1 from the metadata
     // pointer, that is, the pointer-sized word immediately before the
     // pointer's referenced address.
     TargetValueWitnessTable<Runtime> VWT;
     auto ValueWitnessTableAddrAddr = MetadataAddress - sizeof(StoredPointer);
     StoredSignedPointer SignedValueWitnessTableAddr;
-    if (!Reader->readInteger(RemoteAddress(ValueWitnessTableAddrAddr),
+    if (!Reader->readInteger(ValueWitnessTableAddrAddr,
                              &SignedValueWitnessTableAddr))
       return std::nullopt;
-    auto ValueWitnessTableAddr = stripSignedPointer(SignedValueWitnessTableAddr);
-    if (!Reader->readBytes(RemoteAddress(ValueWitnessTableAddr),
-                           (uint8_t *)&VWT, sizeof(VWT)))
+    auto ValueWitnessTableAddr =
+        stripSignedPointer(SignedValueWitnessTableAddr);
+    if (!Reader->readBytes(ValueWitnessTableAddr, (uint8_t *)&VWT, sizeof(VWT)))
       return std::nullopt;
     return VWT;
   }
@@ -718,8 +697,7 @@ class MetadataReader {
   std::optional<RemoteExistential>
   readMetadataAndValueErrorExistential(RemoteAddress ExistentialAddress) {
     // An pointer to an error existential is always an heap object.
-    auto MetadataAddress =
-        readMetadataFromInstance(ExistentialAddress.getAddressData());
+    auto MetadataAddress = readMetadataFromInstance(ExistentialAddress);
     if (!MetadataAddress)
       return std::nullopt;
 
@@ -748,18 +726,15 @@ class MetadataReader {
 
     if (isBridged) {
       // NSError instances don't need to be unwrapped.
-      return RemoteExistential(RemoteAddress(*MetadataAddress),
-                               ExistentialAddress,
-                               isBridged);
+      return RemoteExistential(*MetadataAddress, ExistentialAddress, isBridged);
     }
 
     // In addition to the isa pointer and two 32-bit reference counts, if the
     // error existential is layout-compatible with NSError, we also need to
     // skip over its three word-sized fields: the error code, the domain,
     // and userInfo.
-    StoredPointer InstanceMetadataAddressAddress =
-        ExistentialAddress.getAddressData() +
-        (isObjC ? 5 : 2) * sizeof(StoredPointer);
+    RemoteAddress InstanceMetadataAddressAddress =
+        ExistentialAddress + (isObjC ? 5 : 2) * sizeof(StoredPointer);
 
     // We need to get the instance's alignment info so we can get the exact
     // offset of the start of its data in the class.
@@ -775,7 +750,7 @@ class MetadataReader {
 
     // Now we need to skip over the instance metadata pointer and instance's
     // conformance pointer for Swift.Error.
-    StoredPointer InstanceAddress =
+    RemoteAddress InstanceAddress =
         InstanceMetadataAddressAddress + 2 * sizeof(StoredPointer);
 
     // When built with Objective-C interop, the runtime also stores a conformance
@@ -788,10 +763,8 @@ class MetadataReader {
     auto AlignmentMask = VWT->getAlignmentMask();
     InstanceAddress = (InstanceAddress + AlignmentMask) & ~AlignmentMask;
 
-    return RemoteExistential(
-        RemoteAddress(*InstanceMetadataAddress),
-        RemoteAddress(InstanceAddress),
-        isBridged);
+    return RemoteExistential(*InstanceMetadataAddress, InstanceAddress,
+                             isBridged);
   }
 
   /// Given a known-opaque existential, attempt to discover the pointer to its
@@ -801,10 +774,11 @@ class MetadataReader {
     // OpaqueExistentialContainer is the layout of an opaque existential.
     // `Type` is the pointer to the metadata.
     TargetOpaqueExistentialContainer<Runtime> Container;
-    if (!Reader->readBytes(RemoteAddress(ExistentialAddress),
-                           (uint8_t *)&Container, sizeof(Container)))
+    if (!Reader->readBytes(ExistentialAddress, (uint8_t *)&Container,
+                           sizeof(Container)))
       return std::nullopt;
-    auto MetadataAddress = static_cast<StoredPointer>(Container.Type);
+    auto MetadataAddress =
+        RemoteAddress(Container.Type, ExistentialAddress.getAddressSpace());
     auto Metadata = readMetadata(MetadataAddress);
     if (!Metadata)
       return std::nullopt;
@@ -816,20 +790,19 @@ class MetadataReader {
     // Inline representation (the value fits in the existential container).
     // So, the value starts at the first word of the container.
     if (VWT->isValueInline())
-      return RemoteExistential(RemoteAddress(MetadataAddress),
-                               ExistentialAddress);
+      return RemoteExistential(MetadataAddress, ExistentialAddress);
 
     // Non-inline (box'ed) representation.
     // The first word of the container stores the address to the box.
-    StoredPointer BoxAddress;
-    if (!Reader->readInteger(ExistentialAddress, &BoxAddress))
+    RemoteAddress BoxAddress;
+    if (!Reader->template readRemoteAddress<StoredPointer>(ExistentialAddress,
+                                                           BoxAddress))
       return std::nullopt;
 
     auto AlignmentMask = VWT->getAlignmentMask();
     auto Offset = (sizeof(HeapObject) + AlignmentMask) & ~AlignmentMask;
     auto StartOfValue = BoxAddress + Offset;
-    return RemoteExistential(RemoteAddress(MetadataAddress),
-                             RemoteAddress(StartOfValue));
+    return RemoteExistential(MetadataAddress, StartOfValue);
   }
 
   /// Given a known-opaque existential, discover if its value is inlined in
@@ -839,10 +812,12 @@ class MetadataReader {
     // OpaqueExistentialContainer is the layout of an opaque existential.
     // `Type` is the pointer to the metadata.
     TargetOpaqueExistentialContainer<Runtime> Container;
-    if (!Reader->readBytes(RemoteAddress(ExistentialAddress),
-                           (uint8_t *)&Container, sizeof(Container)))
+    if (!Reader->readBytes(ExistentialAddress, (uint8_t *)&Container,
+                           sizeof(Container)))
       return std::nullopt;
-    auto MetadataAddress = static_cast<StoredPointer>(Container.Type);
+    auto MetadataAddress =
+        RemoteAddress(Container.Type, ExistentialAddress.getAddressSpace());
+
     auto Metadata = readMetadata(MetadataAddress);
     if (!Metadata)
       return std::nullopt;
@@ -855,11 +830,10 @@ class MetadataReader {
   }
 
   /// Read a protocol from a reference to said protocol.
-  template<typename Resolver>
+  template <typename Resolver>
   typename Resolver::Result readProtocol(
-      const TargetProtocolDescriptorRef<Runtime> &ProtocolAddress,
-      Demangler &dem,
-      Resolver resolver) {
+      const RemoteTargetProtocolDescriptorRef<Runtime> &ProtocolAddress,
+      Demangler &dem, Resolver resolver) {
 #if SWIFT_OBJC_INTEROP
     if (Runtime::ObjCInterop) {
       // Check whether we have an Objective-C protocol.
@@ -895,8 +869,7 @@ class MetadataReader {
 #endif
 
     // Swift-native protocol.
-    auto Demangled =
-      readDemanglingForContextDescriptor(
+    auto Demangled = readDemanglingForContextDescriptor(
         stripSignedPointer({ProtocolAddress.getSwiftProtocol()}), dem);
     if (!Demangled)
       return resolver.failure();
@@ -904,12 +877,79 @@ class MetadataReader {
     return resolver.swiftProtocol(Demangled);
   }
 
+  BuiltType readTypeFromShape(
+      RemoteAbsolutePointer shapeAddress,
+      std::function<std::optional<std::vector<BuiltType>>(unsigned)> getArgs) {
+    RemoteAddress addr = shapeAddress.getResolvedAddress();
+    ShapeRef Shape = readShape(addr);
+    if (!Shape)
+      return BuiltType();
+
+    assert(Shape->hasGeneralizationSignature());
+
+    // Pull out the existential type from the mangled type name.
+    Demangler dem;
+    auto mangledExistentialAddr =
+        resolveRelativeField(Shape, Shape->ExistentialType);
+    auto node =
+        readMangledName(mangledExistentialAddr, MangledNameKind::Type, dem);
+    if (!node)
+      return BuiltType();
+
+    BuiltType builtProto = decodeMangledType(node).getType();
+    if (!builtProto)
+      return BuiltType();
+
+    if (auto builtArgs = getArgs(Shape->getGenSigArgumentLayoutSizeInWords())) {
+      // Build up a substitution map for the generalized signature.
+      BuiltGenericSignature sig =
+          decodeRuntimeGenericSignature(Shape,
+                                        Shape->getGeneralizationSignature())
+              .getType();
+      if (!sig)
+        return BuiltType();
+
+      BuiltSubstitutionMap subst =
+          Builder.createSubstitutionMap(sig, *builtArgs);
+      if (subst.empty())
+        return BuiltType();
+
+      builtProto = Builder.subst(builtProto, subst);
+      if (!builtProto)
+        return BuiltType();
+    }
+
+    // Read the type expression to build up any remaining layers of
+    // existential metatype.
+    if (Shape->Flags.hasTypeExpression()) {
+      Demangler dem;
+
+      // Read the mangled name.
+      auto mangledContextName = Shape->getTypeExpression();
+      auto mangledNameAddress =
+          resolveRelativeField(Shape, mangledContextName->name);
+      auto node =
+          readMangledName(mangledNameAddress, MangledNameKind::Type, dem);
+      if (!node)
+        return BuiltType();
+
+      while (node->getKind() == Demangle::Node::Kind::Type &&
+             node->hasChildren() &&
+             node->getChild(0)->getKind() == Demangle::Node::Kind::Metatype &&
+             node->getChild(0)->getNumChildren()) {
+        builtProto = Builder.createExistentialMetatypeType(builtProto);
+        node = node->getChild(0)->getChild(0);
+      }
+    }
+    return builtProto;
+  }
+
   /// Given a remote pointer to metadata, attempt to turn it into a type.
   BuiltType
-  readTypeFromMetadata(StoredPointer MetadataAddress,
+  readTypeFromMetadata(RemoteAddress MetadataAddress,
                        bool skipArtificialSubclasses = false,
                        int recursion_limit = defaultTypeRecursionLimit) {
-    std::pair<StoredPointer, bool> TypeCacheKey(MetadataAddress,
+    std::pair<RemoteAddress, bool> TypeCacheKey(MetadataAddress,
                                                 skipArtificialSubclasses);
     auto Cached = TypeCache.find(TypeCacheKey);
     if (Cached != TypeCache.end())
@@ -952,17 +992,20 @@ class MetadataReader {
 
       for (unsigned i = 0, n = tupleMeta->NumElements; i != n; ++i) {
         auto &element = tupleMeta->getElement(i);
-        if (auto elementType =
-                readTypeFromMetadata(element.Type, false, recursion_limit))
+        auto elementTypeAddress =
+            RemoteAddress(element.Type, MetadataAddress.getAddressSpace());
+        if (auto elementType = readTypeFromMetadata(elementTypeAddress, false,
+                                                    recursion_limit))
           elementTypes.push_back(elementType);
         else
           return BuiltType();
       }
 
       // Read the labels string.
+      auto labelAddress =
+          RemoteAddress(tupleMeta->Labels, MetadataAddress.getAddressSpace());
       std::string labelStr;
-      if (tupleMeta->Labels &&
-          !Reader->readString(RemoteAddress(tupleMeta->Labels), labelStr))
+      if (labelAddress && !Reader->readString(labelAddress, labelStr))
         return BuiltType();
 
       std::vector<llvm::StringRef> labels;
@@ -988,8 +1031,10 @@ class MetadataReader {
 
       std::vector<FunctionParam<BuiltType>> Parameters;
       for (unsigned i = 0, n = Function->getNumParameters(); i != n; ++i) {
-        auto ParamTypeRef = readTypeFromMetadata(Function->getParameter(i),
-                                                 false, recursion_limit);
+        auto paramAddress = RemoteAddress(Function->getParameter(i),
+                                          MetadataAddress.getAddressSpace());
+        auto ParamTypeRef =
+            readTypeFromMetadata(paramAddress, false, recursion_limit);
         if (!ParamTypeRef)
           return BuiltType();
 
@@ -999,8 +1044,10 @@ class MetadataReader {
         Parameters.push_back(std::move(Param));
       }
 
+      auto resultTypeAddress = RemoteAddress(Function->ResultType,
+                                             MetadataAddress.getAddressSpace());
       auto Result =
-          readTypeFromMetadata(Function->ResultType, false, recursion_limit);
+          readTypeFromMetadata(resultTypeAddress, false, recursion_limit);
       if (!Result)
         return BuiltType();
 
@@ -1012,8 +1059,10 @@ class MetadataReader {
 
       BuiltType globalActor = BuiltType();
       if (Function->hasGlobalActor()) {
-        globalActor = readTypeFromMetadata(Function->getGlobalActor(), false,
-                                           recursion_limit);
+        auto globalActorAddress = RemoteAddress(
+            Function->getGlobalActor(), MetadataAddress.getAddressSpace());
+        globalActor =
+            readTypeFromMetadata(globalActorAddress, false, recursion_limit);
         if (!globalActor)
           return BuiltType();
       }
@@ -1035,8 +1084,10 @@ class MetadataReader {
 
       BuiltType thrownError = BuiltType();
       if (Function->hasThrownError()) {
-        thrownError = readTypeFromMetadata(Function->getThrownError(), false,
-                                           recursion_limit);
+        auto thrownErrorAddress = RemoteAddress(
+            Function->getThrownError(), MetadataAddress.getAddressSpace());
+        thrownError =
+            readTypeFromMetadata(thrownErrorAddress, false, recursion_limit);
         if (!thrownError)
           return BuiltType();
       }
@@ -1055,9 +1106,12 @@ class MetadataReader {
 
       BuiltType SuperclassType = BuiltType();
       if (Exist->Flags.hasSuperclassConstraint()) {
+        auto superclassContraintAddress =
+            RemoteAddress(Exist->getSuperclassConstraint(),
+                          MetadataAddress.getAddressSpace());
         // The superclass is stored after the list of protocols.
-        SuperclassType = readTypeFromMetadata(Exist->getSuperclassConstraint(),
-                                              false, recursion_limit);
+        SuperclassType = readTypeFromMetadata(superclassContraintAddress, false,
+                                              recursion_limit);
         if (!SuperclassType) return BuiltType();
 
         HasExplicitAnyObject = true;
@@ -1087,7 +1141,10 @@ class MetadataReader {
       Demangler dem;
       std::vector<BuiltProtocolDecl> Protocols;
       for (auto ProtocolAddress : Exist->getProtocols()) {
-        if (auto Protocol = readProtocol(ProtocolAddress, dem, resolver))
+        auto ProtocolRef = RemoteTargetProtocolDescriptorRef<Runtime>(
+            RemoteAddress(ProtocolAddress.getRawData(),
+                          MetadataAddress.getAddressSpace()));
+        if (auto Protocol = readProtocol(ProtocolRef, dem, resolver))
           Protocols.push_back(Protocol);
         else
           return BuiltType();
@@ -1099,87 +1156,37 @@ class MetadataReader {
     }
     case MetadataKind::ExtendedExistential: {
       auto Exist = cast<TargetExtendedExistentialTypeMetadata<Runtime>>(Meta);
-
       // Read the shape for this existential.
-      StoredPointer shapeAddress = stripSignedPointer(Exist->Shape);
-      ShapeRef Shape = readShape(shapeAddress);
-      if (!Shape)
-        return BuiltType();
-
-      const unsigned shapeArgumentCount
-          = Shape->getGenSigArgumentLayoutSizeInWords();
-      // Pull out the arguments to the generalization signature.
-      assert(Shape->hasGeneralizationSignature());
-      std::vector<BuiltType> builtArgs;
-      for (unsigned i = 0; i < shapeArgumentCount; ++i) {
-        auto remoteArg = Exist->getGeneralizationArguments()[i];
-        auto builtArg = readTypeFromMetadata(remoteArg, false, recursion_limit);
-        if (!builtArg)
-          return BuiltType();
-        builtArgs.push_back(builtArg);
-      }
-
-      // Pull out the existential type from the mangled type name.
-      Demangler dem;
-      auto mangledExistentialAddr =
-          resolveRelativeField(Shape, Shape->ExistentialType);
-      auto node = readMangledName(RemoteAddress(mangledExistentialAddr),
-                                  MangledNameKind::Type, dem);
-      if (!node)
-        return BuiltType();
-
-      BuiltType builtProto = decodeMangledType(node).getType();
-      if (!builtProto)
-        return BuiltType();
-
-      // Build up a substitution map for the generalized signature.
-      BuiltGenericSignature sig =
-          decodeRuntimeGenericSignature(Shape,
-                                        Shape->getGeneralizationSignature())
-              .getType();
-      if (!sig)
-        return BuiltType();
-
-      BuiltSubstitutionMap subst =
-          Builder.createSubstitutionMap(sig, builtArgs);
-      if (subst.empty())
-        return BuiltType();
-
-      builtProto = Builder.subst(builtProto, subst);
-      if (!builtProto)
-        return BuiltType();
-
-      // Read the type expression to build up any remaining layers of
-      // existential metatype.
-      if (Shape->Flags.hasTypeExpression()) {
-        Demangler dem;
-
-        // Read the mangled name.
-        auto mangledContextName = Shape->getTypeExpression();
-        auto mangledNameAddress =
-            resolveRelativeField(Shape, mangledContextName->name);
-        auto node = readMangledName(RemoteAddress(mangledNameAddress),
-                                    MangledNameKind::Type, dem);
-        if (!node)
-          return BuiltType();
-
-        while (node->getKind() == Demangle::Node::Kind::Type &&
-               node->getNumChildren() &&
-               node->getChild(0)->getKind() == Demangle::Node::Kind::Metatype &&
-               node->getChild(0)->getNumChildren()) {
-          builtProto = Builder.createExistentialMetatypeType(builtProto);
-          node = node->getChild(0)->getChild(0);
-        }
-      }
 
+      RemoteAddress shapeAddress = stripSignedPointer(Exist->Shape);
+      auto builtProto = readTypeFromShape(
+          RemoteAddress(shapeAddress),
+          [&](unsigned shapeArgumentCount)
+              -> std::optional<std::vector<BuiltType>> {
+            // Pull out the arguments to the generalization signature.
+            std::vector<BuiltType> builtArgs;
+            for (unsigned i = 0; i < shapeArgumentCount; ++i) {
+              auto remoteArg = Exist->getGeneralizationArguments()[i];
+              auto builtArg = readTypeFromMetadata(
+                  remote::RemoteAddress(remoteArg,
+                                        shapeAddress.getAddressSpace()),
+                  false, recursion_limit);
+              if (!builtArg)
+                return std::nullopt;
+              builtArgs.push_back(builtArg);
+            }
+            return builtArgs;
+          });
       TypeCache[TypeCacheKey] = builtProto;
       return builtProto;
     }
 
     case MetadataKind::Metatype: {
       auto Metatype = cast<TargetMetatypeMetadata<Runtime>>(Meta);
+      auto InstanceTypeAddress = RemoteAddress(
+          Metatype->InstanceType, MetadataAddress.getAddressSpace());
       auto Instance =
-          readTypeFromMetadata(Metatype->InstanceType, false, recursion_limit);
+          readTypeFromMetadata(InstanceTypeAddress, false, recursion_limit);
       if (!Instance) return BuiltType();
       auto BuiltMetatype = Builder.createMetatypeType(Instance);
       TypeCache[TypeCacheKey] = BuiltMetatype;
@@ -1187,7 +1194,8 @@ class MetadataReader {
     }
     case MetadataKind::ObjCClassWrapper: {
       auto objcWrapper = cast<TargetObjCClassWrapperMetadata<Runtime>>(Meta);
-      auto classAddress = objcWrapper->Class;
+      auto classAddress =
+          RemoteAddress(objcWrapper->Class, MetadataAddress.getAddressSpace());
 
       std::string className;
       if (!readObjCClassName(classAddress, className))
@@ -1199,8 +1207,10 @@ class MetadataReader {
     }
     case MetadataKind::ExistentialMetatype: {
       auto Exist = cast<TargetExistentialMetatypeMetadata<Runtime>>(Meta);
+      auto classAddress =
+          RemoteAddress(Exist->InstanceType, MetadataAddress.getAddressSpace());
       auto Instance =
-          readTypeFromMetadata(Exist->InstanceType, false, recursion_limit);
+          readTypeFromMetadata(classAddress, false, recursion_limit);
       if (!Instance) return BuiltType();
       auto BuiltExist = Builder.createExistentialMetatypeType(Instance);
       TypeCache[TypeCacheKey] = BuiltExist;
@@ -1281,8 +1291,13 @@ class MetadataReader {
       switch (req.Flags.getKind()) {
       case GenericRequirementKind::SameType: {
         Demangler rdem;
+        // FIXME: This should not work since the mangled name pointer is on the
+        // local process.
+        auto mangledNameAddress =
+            RemoteAddress((uint64_t)req.getMangledTypeName().data(),
+                          RemoteAddress::DefaultAddressSpace);
         auto demangledConstraint =
-            demangle(RemoteRef<char>(req.getMangledTypeName().data(),
+            demangle(RemoteRef<char>(mangledNameAddress,
                                      req.getMangledTypeName().data()),
                      MangledNameKind::Type, rdem);
         auto constraintType = decodeMangledType(demangledConstraint);
@@ -1323,7 +1338,9 @@ class MetadataReader {
         Demangler dem;
         auto protocolAddress =
             resolveRelativeIndirectProtocol(contextRef, req.Protocol);
-        auto protocol = readProtocol(protocolAddress, dem, resolver);
+        auto protocolRef =
+            RemoteTargetProtocolDescriptorRef<Runtime>(protocolAddress);
+        auto protocol = readProtocol(protocolRef, dem, resolver);
         if (!protocol) {
           return TypeLookupError("Failed to read protocol type in conformance "
                                  "requirement of runtime generic signature.");
@@ -1335,8 +1352,13 @@ class MetadataReader {
       }
       case GenericRequirementKind::BaseClass: {
         Demangler rdem;
+        // FIXME: This should not work since the mangled name pointer is on the
+        // local process.
+        auto mangledNameAddress =
+            RemoteAddress((uint64_t)req.getMangledTypeName().data(),
+                          RemoteAddress::DefaultAddressSpace);
         auto demangledConstraint =
-            demangle(RemoteRef<char>(req.getMangledTypeName().data(),
+            demangle(RemoteRef<char>(mangledNameAddress,
                                      req.getMangledTypeName().data()),
                      MangledNameKind::Type, rdem);
         auto constraintType = decodeMangledType(demangledConstraint);
@@ -1379,90 +1401,84 @@ class MetadataReader {
   ParentContextDescriptorRef
   readContextDescriptor(const RemoteAbsolutePointer &address) {
     // Map an unresolved pointer to an unresolved context ref.
-    if (!address.isResolved()) {
+    if (!address.getSymbol().empty()) {
       // We can only handle references to a symbol without an offset currently.
-      if (address.getOffset() != 0) {
-        return ParentContextDescriptorRef();
-      }
-      return ParentContextDescriptorRef(address.getSymbol());
+      if (address.getOffset() == 0)
+        return ParentContextDescriptorRef(address.getSymbol());
     }
-    
+
     return ParentContextDescriptorRef(
-          readContextDescriptor(address.getResolvedAddress().getAddressData()));
+        readContextDescriptor(address.getResolvedAddress()));
   }
 
-  ShapeRef
-  readShape(StoredPointer address) {
-    if (address == 0)
+  ShapeRef readShape(RemoteAddress address) {
+    if (!address)
       return nullptr;
 
+    using ShapeHeader = TargetExtendedExistentialTypeShape<Runtime>;
     auto cached = ShapeCache.find(address);
     if (cached != ShapeCache.end())
-      return ShapeRef(address,
-        reinterpret_cast<const TargetExtendedExistentialTypeShape<Runtime> *>(
-            cached->second.get()));
+      return ShapeRef(
+          address, reinterpret_cast<const ShapeHeader *>(cached->second.get()));
 
     ExtendedExistentialTypeShapeFlags flags;
-    if (!Reader->readBytes(RemoteAddress(address), (uint8_t*)&flags,
-                           sizeof(flags)))
+    if (!Reader->readBytes(address, (uint8_t *)&flags, sizeof(flags)))
       return nullptr;
 
     // Read the size of the requirement signature.
-    uint64_t reqSigGenericSize = 0;
-    uint64_t genericHeaderSize = sizeof(GenericContextDescriptorHeader);
+    uint64_t descriptorSize;
     {
-      GenericContextDescriptorHeader header;
-      auto headerAddr = address + sizeof(flags);
-
-      if (!Reader->readBytes(RemoteAddress(headerAddr),
-                             (uint8_t*)&header, sizeof(header)))
+      auto readResult =
+          Reader->readBytes(RemoteAddress(address), sizeof(ShapeHeader));
+      if (!readResult)
         return nullptr;
-
-      reqSigGenericSize = reqSigGenericSize
-        + (header.NumParams + 3u & ~3u)
-        + header.NumRequirements
-          * sizeof(TargetGenericRequirementDescriptor<Runtime>);
-    }
-    uint64_t typeExprSize = flags.hasTypeExpression() ? sizeof(StoredPointer) : 0;
-    uint64_t suggestedVWSize = flags.hasSuggestedValueWitnesses() ? sizeof(StoredPointer) : 0;
-
-    uint64_t size = sizeof(ExtendedExistentialTypeShapeFlags) +
-                    sizeof(TargetRelativeDirectPointer<Runtime, const char,
-                                                       /*nullable*/ false>) +
-                    genericHeaderSize + typeExprSize + suggestedVWSize +
-                    reqSigGenericSize;
-    if (size > MaxMetadataSize)
+      auto shapeHeader =
+          reinterpret_cast<const ShapeHeader *>(readResult.get());
+
+      // Read the size of the requirement signature.
+      uint64_t reqSigGenericSize = 0;
+      auto flags = shapeHeader->Flags;
+      auto &reqSigHeader = shapeHeader->ReqSigHeader;
+      reqSigGenericSize =
+          reqSigGenericSize + (reqSigHeader.NumParams + 3u & ~3u) +
+          reqSigHeader.NumRequirements *
+              sizeof(TargetGenericRequirementDescriptor<Runtime>);
+      uint64_t typeExprSize =
+          flags.hasTypeExpression() ? sizeof(StoredPointer) : 0;
+      uint64_t suggestedVWSize =
+          flags.hasSuggestedValueWitnesses() ? sizeof(StoredPointer) : 0;
+
+      descriptorSize = sizeof(shapeHeader) + typeExprSize + suggestedVWSize +
+                       reqSigGenericSize;
+    }
+    if (descriptorSize > MaxMetadataSize)
       return nullptr;
-    auto readResult = Reader->readBytes(RemoteAddress(address), size);
+    auto readResult = Reader->readBytes(RemoteAddress(address), descriptorSize);
     if (!readResult)
       return nullptr;
 
-    auto descriptor =
-        reinterpret_cast<const TargetExtendedExistentialTypeShape<Runtime> *>(
-            readResult.get());
+    auto descriptor = reinterpret_cast<const ShapeHeader *>(readResult.get());
 
-    ShapeCache.insert(
-        std::make_pair(address, std::move(readResult)));
+    ShapeCache.insert(std::make_pair(address, std::move(readResult)));
     return ShapeRef(address, descriptor);
   }
 
   /// Given the address of a context descriptor, attempt to read it.
-  ContextDescriptorRef
-  readContextDescriptor(StoredPointer address) {
-    if (address == 0)
+  ContextDescriptorRef readContextDescriptor(RemoteAddress remoteAddress) {
+    if (!remoteAddress)
       return nullptr;
 
-    auto remoteAddress = RemoteAddress(address);
     auto ptr = Reader->readBytes(remoteAddress,
                                  sizeof(TargetContextDescriptor<Runtime>));
     if (!ptr)
       return nullptr;
 
-    auto cached = ContextDescriptorCache.find(address);
+    auto cached = ContextDescriptorCache.find(remoteAddress);
     if (cached != ContextDescriptorCache.end())
       return ContextDescriptorRef(
-          address, reinterpret_cast<const TargetContextDescriptor<Runtime> *>(
-                       cached->second.get()));
+          remoteAddress,
+          reinterpret_cast<const TargetContextDescriptor<Runtime> *>(
+              cached->second.get()));
 
     bool success = false;
     switch (
@@ -1512,8 +1528,9 @@ class MetadataReader {
 
     auto *descriptor =
         reinterpret_cast<const TargetContextDescriptor<Runtime> *>(ptr.get());
-    ContextDescriptorCache.insert(std::make_pair(address, std::move(ptr)));
-    return ContextDescriptorRef(address, descriptor);
+    ContextDescriptorCache.insert(
+        std::make_pair(remoteAddress, std::move(ptr)));
+    return ContextDescriptorRef(remoteAddress, descriptor);
   }
 
   template <typename DescriptorTy>
@@ -1626,19 +1643,17 @@ class MetadataReader {
   /// Read a context descriptor from the given address and build a mangling
   /// tree representing it.
   Demangle::NodePointer
-  readDemanglingForContextDescriptor(StoredPointer contextAddress,
+  readDemanglingForContextDescriptor(RemoteAddress contextAddress,
                                      Demangler &Dem) {
     auto context = readContextDescriptor(contextAddress);
     if (!context)
       return nullptr;
     return buildContextMangling(context, Dem);
   }
-  
+
   /// Read the mangled underlying type from an opaque type descriptor.
-  Demangle::NodePointer
-  readUnderlyingTypeManglingForOpaqueTypeDescriptor(StoredPointer contextAddr,
-                                                    unsigned ordinal,
-                                                    Demangler &Dem) {
+  Demangle::NodePointer readUnderlyingTypeManglingForOpaqueTypeDescriptor(
+      RemoteAddress contextAddr, unsigned ordinal, Demangler &Dem) {
     auto context = readContextDescriptor(contextAddr);
     if (!context)
       return nullptr;
@@ -1654,13 +1669,12 @@ class MetadataReader {
     
     auto nameAddr = resolveRelativeField(context,
                      opaqueType->getUnderlyingTypeArgumentMangledName(ordinal));
-    
-    return readMangledName(RemoteAddress(nameAddr),
-                                MangledNameKind::Type, Dem);
+
+    return readMangledName(nameAddr, MangledNameKind::Type, Dem);
   }
 
   TypeLookupErrorOr<typename BuilderType::BuiltType>
-  readUnderlyingTypeForOpaqueTypeDescriptor(StoredPointer contextAddr,
+  readUnderlyingTypeForOpaqueTypeDescriptor(RemoteAddress contextAddr,
                                             unsigned ordinal) {
     Demangle::Demangler Dem;
     auto node = readUnderlyingTypeManglingForOpaqueTypeDescriptor(contextAddr,
@@ -1670,31 +1684,33 @@ class MetadataReader {
     return decodeMangledType(node);
   }
 
-  bool isTaggedPointer(StoredPointer objectAddress) {
+  bool isTaggedPointer(RemoteAddress objectAddress) {
     if (getTaggedPointerEncoding() != TaggedPointerEncodingKind::Extended)
       return false;
-  
-    return (objectAddress ^ TaggedPointerObfuscator) & TaggedPointerMask;
+
+    return (bool)((objectAddress ^ TaggedPointerObfuscator) &
+                  TaggedPointerMask);
   }
 
   /// Read the isa pointer of an Object-C tagged pointer value.
-  std::optional<StoredPointer>
-  readMetadataFromTaggedPointer(StoredPointer objectAddress) {
+  std::optional<RemoteAddress>
+  readMetadataFromTaggedPointer(RemoteAddress objectAddress) {
     auto readArrayElement =
-        [&](StoredPointer base,
-            StoredPointer tag) -> std::optional<StoredPointer> {
-      StoredPointer addr = base + tag * sizeof(StoredPointer);
-      StoredPointer isa;
-      if (!Reader->readInteger(RemoteAddress(addr), &isa))
+        [&](RemoteAddress base,
+            StoredPointer tag) -> std::optional<RemoteAddress> {
+      RemoteAddress addr = base + tag * sizeof(StoredPointer);
+      RemoteAddress isa;
+      if (!Reader->template readRemoteAddress<StoredPointer>(addr, isa))
         return std::nullopt;
       return isa;
     };
 
     // Extended pointers have a tag of 0b111, using 8 additional bits
     // to specify the class.
-    if (TaggedPointerExtendedMask != 0 &&
-        (((objectAddress ^ TaggedPointerObfuscator) & TaggedPointerExtendedMask)
-           == TaggedPointerExtendedMask)) {
+    if (TaggedPointerExtendedMask &&
+        ((((StoredPointer)objectAddress.getRawAddress() ^
+           TaggedPointerObfuscator) &
+          TaggedPointerExtendedMask) == TaggedPointerExtendedMask)) {
       auto tag = ((objectAddress >> TaggedPointerExtendedSlotShift) &
                   TaggedPointerExtendedSlotMask);
       return readArrayElement(TaggedPointerExtendedClasses, tag);
@@ -1708,13 +1724,13 @@ class MetadataReader {
 
   /// Read the isa pointer of a class or closure context instance and apply
   /// the isa mask.
-  std::optional<StoredPointer>
-  readMetadataFromInstance(StoredPointer objectAddress) {
+  std::optional<RemoteAddress>
+  readMetadataFromInstance(RemoteAddress objectAddress) {
     if (isTaggedPointer(objectAddress))
       return readMetadataFromTaggedPointer(objectAddress);
 
-    StoredPointer isa;
-    if (!Reader->readInteger(RemoteAddress(objectAddress), &isa))
+    RemoteAddress isa;
+    if (!Reader->template readRemoteAddress<StoredPointer>(objectAddress, isa))
       return std::nullopt;
 
     switch (getIsaEncoding()) {
@@ -1731,11 +1747,12 @@ class MetadataReader {
     case IsaEncodingKind::Indexed: {
       // If applying the magic mask doesn't give us the magic value,
       // it's not an indexed isa.
-      if ((isa & IsaMagicMask) != IsaMagicValue)
+      if (((StoredPointer)(isa & IsaMagicMask).getRawAddress()) !=
+          IsaMagicValue)
         return isa;
 
       // Extract the index.
-      auto classIndex = (isa & IsaIndexMask) >> IsaIndexShift;
+      StoredPointer classIndex = (isa & IsaIndexMask) >> IsaIndexShift;
 
       // 0 is never a valid index.
       if (classIndex == 0) {
@@ -1761,10 +1778,10 @@ class MetadataReader {
       RemoteAddress eltPointer =
         RemoteAddress(IndexedClassesPointer
                         + classIndex * sizeof(StoredPointer));
-      StoredPointer metadataPointer;
-      if (!Reader->readInteger(eltPointer, &metadataPointer)) {
+      RemoteAddress metadataPointer;
+      if (!Reader->template readRemoteAddress<StoredPointer>(eltPointer,
+                                                             metadataPointer))
         return std::nullopt;
-      }
 
       return metadataPointer;
     }
@@ -1865,7 +1882,7 @@ class MetadataReader {
 
             return cls->getClassBoundsAsSwiftSuperclass();
           },
-          [](StoredPointer objcClassName)
+          [](RemoteAddress objcClassName)
               -> std::optional<ClassMetadataBounds> {
             // We have no ability to look up an ObjC class by name.
             // FIXME: add a query for this; clients may have a way to do it.
@@ -1883,14 +1900,14 @@ class MetadataReader {
   template <class Result, class DescriptorFn, class MetadataFn,
             class ClassNameFn>
   std::optional<Result> forTypeReference(TypeReferenceKind refKind,
-                                         StoredPointer ref,
+                                         RemoteAddress ref,
                                          const DescriptorFn &descriptorFn,
                                          const MetadataFn &metadataFn,
                                          const ClassNameFn &classNameFn) {
     switch (refKind) {
     case TypeReferenceKind::IndirectTypeDescriptor: {
       StoredSignedPointer descriptorAddress;
-      if (!Reader->readInteger(RemoteAddress(ref), &descriptorAddress)) {
+      if (!Reader->readInteger(ref, &descriptorAddress)) {
         return std::nullopt;
       }
 
@@ -1910,8 +1927,8 @@ class MetadataReader {
       return classNameFn(ref);
 
     case TypeReferenceKind::IndirectObjCClass: {
-      StoredPointer classRef = 0;
-      if (!Reader->readInteger(RemoteAddress(ref), &classRef))
+      RemoteAddress classRef;
+      if (!Reader->template readRemoteAddress<StoredPointer>(ref, classRef))
         return std::nullopt;
 
       auto metadata = readMetadata(classRef);
@@ -1927,8 +1944,8 @@ class MetadataReader {
 
   /// Read a single generic type argument from a bound generic type
   /// metadata.
-  std::optional<StoredPointer>
-  readGenericArgFromMetadata(StoredPointer metadata, unsigned index) {
+  std::optional<RemoteAddress>
+  readGenericArgFromMetadata(RemoteAddress metadata, unsigned index) {
     auto Meta = readMetadata(metadata);
     if (!Meta)
       return std::nullopt;
@@ -1958,9 +1975,9 @@ class MetadataReader {
     if (index >= generics->getGenericContextHeader().getNumArguments())
       return std::nullopt;
 
-    StoredPointer genericArgAddress;
-    if (!Reader->readInteger(RemoteAddress(addressOfGenericArgAddress),
-                             &genericArgAddress))
+    RemoteAddress genericArgAddress;
+    if (!Reader->template readRemoteAddress<StoredPointer>(
+            addressOfGenericArgAddress, genericArgAddress))
       return std::nullopt;
 
     return genericArgAddress;
@@ -1968,7 +1985,7 @@ class MetadataReader {
 
   /// Given the address of a nominal type descriptor, attempt to resolve
   /// its nominal type declaration.
-  BuiltTypeDecl readNominalTypeFromDescriptor(StoredPointer address) {
+  BuiltTypeDecl readNominalTypeFromDescriptor(RemoteAddress address) {
     auto descriptor = readContextDescriptor(address);
     if (!descriptor)
       return BuiltTypeDecl();
@@ -1977,7 +1994,7 @@ class MetadataReader {
   }
 
   /// Try to read the offset of a tuple element from a tuple metadata.
-  bool readTupleElementOffset(StoredPointer metadataAddress, unsigned eltIndex,
+  bool readTupleElementOffset(RemoteAddress metadataAddress, unsigned eltIndex,
                               StoredSize *offset) {
     // Read the metadata.
     auto metadata = readMetadata(metadataAddress);
@@ -2001,7 +2018,7 @@ class MetadataReader {
 
   /// Given a remote pointer to class metadata, attempt to read its superclass.
   std::optional<StoredPointer>
-  readOffsetToFirstCaptureFromMetadata(StoredPointer MetadataAddress) {
+  readOffsetToFirstCaptureFromMetadata(RemoteAddress MetadataAddress) {
     auto meta = readMetadata(MetadataAddress);
     if (!meta || meta->getKind() != MetadataKind::HeapLocalVariable)
       return std::nullopt;
@@ -2010,15 +2027,15 @@ class MetadataReader {
     return heapMeta->OffsetToFirstCapture;
   }
 
-  std::optional<RemoteAbsolutePointer> readPointer(StoredPointer address) {
-    return Reader->readPointer(RemoteAddress(address), sizeof(StoredPointer));
+  std::optional<RemoteAbsolutePointer> readPointer(RemoteAddress address) {
+    return Reader->readPointer(address, sizeof(StoredPointer));
   }
 
-  std::optional<StoredPointer> readResolvedPointerValue(StoredPointer address) {
+  std::optional<RemoteAddress> readResolvedPointerValue(RemoteAddress address) {
     if (auto pointer = readPointer(address)) {
-      if (!pointer->isResolved())
+      if (!pointer->getResolvedAddress())
         return std::nullopt;
-      return (StoredPointer)pointer->getResolvedAddress().getAddressData();
+      return pointer->getResolvedAddress();
     }
     return std::nullopt;
   }
@@ -2027,13 +2044,13 @@ class MetadataReader {
   RemoteAbsolutePointer resolvePointerField(RemoteRef<T> base,
                                             const U &field) {
     auto pointerRef = base.getField(field);
-    return Reader->resolvePointer(RemoteAddress(getAddress(pointerRef)),
+    return Reader->resolvePointer(getAddress(pointerRef),
                                   *pointerRef.getLocalBuffer());
   }
 
   /// Given a remote pointer to class metadata, attempt to read its superclass.
   std::optional<RemoteAbsolutePointer>
-  readCaptureDescriptorFromMetadata(StoredPointer MetadataAddress) {
+  readCaptureDescriptorFromMetadata(RemoteAddress MetadataAddress) {
     auto meta = readMetadata(MetadataAddress);
     if (!meta || meta->getKind() != MetadataKind::HeapLocalVariable)
       return std::nullopt;
@@ -2043,15 +2060,14 @@ class MetadataReader {
   }
 
 protected:
-  template<typename Base>
-  StoredPointer getAddress(RemoteRef<Base> base) {
-    return (StoredPointer)base.getAddressData();
+  template <typename Base>
+  RemoteAddress getAddress(RemoteRef<Base> base) {
+    return base.getRemoteAddress();
   }
-  
-  template<typename Base, typename Field>
-  StoredPointer resolveRelativeField(
-                            RemoteRef<Base> base, const Field &field) {
-    return (StoredPointer)base.resolveRelativeFieldData(field);
+
+  template <typename Base, typename Field>
+  RemoteAddress resolveRelativeField(RemoteRef<Base> base, const Field &field) {
+    return base.resolveRelativeFieldData(field);
   }
 
   template <typename Base, typename Field>
@@ -2067,9 +2083,9 @@ class MetadataReader {
     offset &= ~1u;
     
     using SignedPointer = typename std::make_signed<StoredPointer>::type;
-    
-    StoredPointer resultAddress = getAddress(fieldRef) + (SignedPointer)offset;
-    
+
+    RemoteAddress resultAddress = getAddress(fieldRef) + (SignedPointer)offset;
+
     // Low bit set in the offset indicates that the offset leads to the absolute
     // address in memory.
     if (indirect) {
@@ -2078,16 +2094,16 @@ class MetadataReader {
       }
       return std::nullopt;
     }
-    
-    return RemoteAbsolutePointer("", resultAddress);
+
+    return RemoteAbsolutePointer(resultAddress);
   }
 
   /// Given a pointer to an Objective-C class, try to read its class name.
-  bool readObjCClassName(StoredPointer classAddress, std::string &className) {
+  bool readObjCClassName(RemoteAddress classAddress, std::string &className) {
     // The following algorithm only works on the non-fragile Apple runtime.
 
     // Grab the RO-data pointer.  This part is not ABI.
-    StoredPointer roDataPtr = readObjCRODataPtr(classAddress);
+    RemoteAddress roDataPtr = readObjCRODataPtr(classAddress);
     if (!roDataPtr) return false;
 
     // This is ABI.
@@ -2096,18 +2112,19 @@ class MetadataReader {
       + sizeof(StoredPointer);
 
     // Read the name pointer.
-    StoredPointer namePtr;
-    if (!Reader->readInteger(RemoteAddress(roDataPtr + OffsetToName), &namePtr))
+    RemoteAddress namePtr;
+    if (!Reader->template readRemoteAddress<StoredPointer>(
+            roDataPtr + OffsetToName, namePtr))
       return false;
 
     // If the name pointer is null, treat that as an error.
     if (!namePtr)
       return false;
 
-    return Reader->readString(RemoteAddress(namePtr), className);
+    return Reader->readString(namePtr, className);
   }
 
-  MetadataRef readMetadata(StoredPointer address) {
+  MetadataRef readMetadata(RemoteAddress address) {
     auto cached = MetadataCache.find(address);
     if (cached != MetadataCache.end())
       return MetadataRef(address,
@@ -2115,7 +2132,7 @@ class MetadataReader {
                              cached->second.get()));
 
     StoredPointer KindValue = 0;
-    if (!Reader->readInteger(RemoteAddress(address), &KindValue))
+    if (!Reader->readInteger(address, &KindValue))
       return nullptr;
 
     switch (getEnumeratedMetadataKind(KindValue)) {
@@ -2128,20 +2145,17 @@ class MetadataReader {
       case MetadataKind::ErrorObject:
         return _readMetadata<TargetEnumMetadata>(address);
       case MetadataKind::Existential: {
-        StoredPointer flagsAddress = address +
-          sizeof(StoredPointer);
+        RemoteAddress flagsAddress = address + sizeof(StoredPointer);
 
         ExistentialTypeFlags::int_type flagsData;
-        if (!Reader->readInteger(RemoteAddress(flagsAddress),
-                                 &flagsData))
+        if (!Reader->readInteger(flagsAddress, &flagsData))
           return nullptr;
 
         ExistentialTypeFlags flags(flagsData);
 
-        StoredPointer numProtocolsAddress = flagsAddress + sizeof(flagsData);
+        RemoteAddress numProtocolsAddress = flagsAddress + sizeof(flagsData);
         uint32_t numProtocols;
-        if (!Reader->readInteger(RemoteAddress(numProtocolsAddress),
-                                 &numProtocols))
+        if (!Reader->readInteger(numProtocolsAddress, &numProtocols))
           return nullptr;
 
         // Make sure the number of protocols is reasonable
@@ -2162,9 +2176,10 @@ class MetadataReader {
       case MetadataKind::ExtendedExistential: {
         // We need to read the shape in order to figure out how large
         // the generalization arguments are.
-        StoredPointer shapeAddress = address + sizeof(StoredPointer);
-        StoredSignedPointer signedShapePtr;
-        if (!Reader->readInteger(RemoteAddress(shapeAddress), &signedShapePtr))
+        RemoteAddress shapeAddress = address + sizeof(StoredPointer);
+        RemoteAddress signedShapePtr;
+        if (!Reader->template readRemoteAddress<StoredPointer>(shapeAddress,
+                                                               signedShapePtr))
           return nullptr;
         auto shapePtr = stripSignedPointer(signedShapePtr);
 
@@ -2186,7 +2201,7 @@ class MetadataReader {
         StoredSize flagsValue;
         auto flagsAddr =
             address + TargetFunctionTypeMetadata<Runtime>::OffsetToFlags;
-        if (!Reader->readInteger(RemoteAddress(flagsAddr), &flagsValue))
+        if (!Reader->readInteger(flagsAddr, &flagsValue))
           return nullptr;
 
         auto flags =
@@ -2223,8 +2238,7 @@ class MetadataReader {
         auto numElementsAddress = address +
           TargetTupleTypeMetadata<Runtime>::getOffsetToNumElements();
         StoredSize numElements;
-        if (!Reader->readInteger(RemoteAddress(numElementsAddress),
-                                 &numElements))
+        if (!Reader->readInteger(numElementsAddress, &numElements))
           return nullptr;
         auto totalSize = sizeof(TargetTupleTypeMetadata<Runtime>) +
                          numElements * sizeof(TupleTypeMetadata::Element);
@@ -2245,7 +2259,7 @@ class MetadataReader {
     return nullptr;
   }
 
-  StoredPointer
+  RemoteAddress
   readAddressOfNominalTypeDescriptor(MetadataRef &metadata,
                                      bool skipArtificialSubclasses = false) {
     switch (metadata->getKind()) {
@@ -2253,28 +2267,29 @@ class MetadataReader {
       auto classMeta = cast<TargetClassMetadata>(metadata);
       while (true) {
         if (!classMeta->isTypeMetadata())
-          return 0;
+          return RemoteAddress();
 
         StoredSignedPointer descriptorAddressSigned = classMeta->getDescriptionAsSignedPointer();
-        StoredPointer descriptorAddress = stripSignedPointer(descriptorAddressSigned);
+        RemoteAddress descriptorAddress =
+            stripSignedPointer(descriptorAddressSigned);
 
         // If this class has a null descriptor, it's artificial,
         // and we need to skip it upon request.  Otherwise, we're done.
         if (descriptorAddress || !skipArtificialSubclasses)
-          return static_cast<StoredPointer>(descriptorAddress);
+          return descriptorAddress;
 
         auto superclassMetadataAddress =
             stripSignedPointer(classMeta->Superclass);
         if (!superclassMetadataAddress)
-          return 0;
+          return RemoteAddress();
 
         auto superMeta = readMetadata(superclassMetadataAddress);
         if (!superMeta)
-          return 0;
+          return RemoteAddress();
 
         auto superclassMeta = dyn_cast<TargetClassMetadata>(superMeta);
         if (!superclassMeta)
-          return 0;
+          return RemoteAddress();
 
         classMeta = superclassMeta;
         metadata = superMeta;
@@ -2286,39 +2301,42 @@ class MetadataReader {
     case MetadataKind::Enum: {
       auto valueMeta = cast<TargetValueMetadata<Runtime>>(metadata);
       StoredSignedPointer descriptorAddressSigned = valueMeta->getDescriptionAsSignedPointer();
-      StoredPointer descriptorAddress = stripSignedPointer(descriptorAddressSigned);
+      RemoteAddress descriptorAddress =
+          stripSignedPointer(descriptorAddressSigned);
       return descriptorAddress;
     }
         
     case MetadataKind::ForeignClass: {
       auto foreignMeta = cast<TargetForeignClassMetadata<Runtime>>(metadata);
       StoredSignedPointer descriptorAddressSigned = foreignMeta->getDescriptionAsSignedPointer();
-      StoredPointer descriptorAddress = stripSignedPointer(descriptorAddressSigned);
+      RemoteAddress descriptorAddress =
+          stripSignedPointer(descriptorAddressSigned);
       return descriptorAddress;
     }
 
     case MetadataKind::ForeignReferenceType: {
       auto foreignMeta = cast<TargetForeignReferenceTypeMetadata<Runtime>>(metadata);
       StoredSignedPointer descriptorAddressSigned = foreignMeta->getDescriptionAsSignedPointer();
-      StoredPointer descriptorAddress = stripSignedPointer(descriptorAddressSigned);
+      RemoteAddress descriptorAddress =
+          stripSignedPointer(descriptorAddressSigned);
       return descriptorAddress;
     }
 
     default:
-      return 0;
+      return RemoteAddress();
     }
   }
 
 private:
   template <template <class R> class M>
-  MetadataRef _readMetadata(StoredPointer address) {
+  MetadataRef _readMetadata(RemoteAddress address) {
     return _readMetadata(address, sizeof(M<Runtime>));
   }
 
-  MetadataRef _readMetadata(StoredPointer address, size_t sizeAfter) {
+  MetadataRef _readMetadata(RemoteAddress address, size_t sizeAfter) {
     if (sizeAfter > MaxMetadataSize)
       return nullptr;
-    auto readResult = Reader->readBytes(RemoteAddress(address), sizeAfter);
+    auto readResult = Reader->readBytes(address, sizeAfter);
     if (!readResult)
       return nullptr;
 
@@ -2335,18 +2353,16 @@ class MetadataReader {
     auto parentAddress = resolveRelativeIndirectableField(base, base->Parent);
     if (!parentAddress)
       return std::nullopt;
-    if (!parentAddress->isResolved()) {
+    if (!parentAddress->getSymbol().empty()) {
       // Currently we can only handle references directly to a symbol without
       // an offset.
-      if (parentAddress->getOffset() != 0) {
-        return std::nullopt;
-      }
-      return ParentContextDescriptorRef(parentAddress->getSymbol());
+      if (parentAddress->getOffset() == 0)
+        return ParentContextDescriptorRef(parentAddress->getSymbol());
     }
     auto addr = parentAddress->getResolvedAddress();
     if (!addr)
       return ParentContextDescriptorRef();
-    if (auto parentDescriptor = readContextDescriptor(addr.getAddressData()))
+    if (auto parentDescriptor = readContextDescriptor(addr))
       return ParentContextDescriptorRef(parentDescriptor);
     return std::nullopt;
   }
@@ -2374,7 +2390,7 @@ class MetadataReader {
     if (auto protoBuffer =
             dyn_cast<TargetProtocolDescriptor<Runtime>>(context)) {
       auto nameAddress = resolveRelativeField(descriptor, protoBuffer->Name);
-      if (Reader->readString(RemoteAddress(nameAddress), name))
+      if (Reader->readString(nameAddress, name))
         return name;
 
       return std::nullopt;
@@ -2384,7 +2400,7 @@ class MetadataReader {
     if (auto moduleBuffer =
             dyn_cast<TargetModuleContextDescriptor<Runtime>>(context)) {
       auto nameAddress = resolveRelativeField(descriptor, moduleBuffer->Name);
-      if (Reader->readString(RemoteAddress(nameAddress), name))
+      if (Reader->readString(nameAddress, name))
         return name;
 
       return std::nullopt;
@@ -2396,7 +2412,7 @@ class MetadataReader {
       return std::nullopt;
 
     auto nameAddress = resolveRelativeField(descriptor, typeBuffer->Name);
-    if (!Reader->readString(RemoteAddress(nameAddress), name))
+    if (!Reader->readString(nameAddress, name))
       return std::nullopt;
 
     // Read the TypeImportInfo if present.
@@ -2407,7 +2423,7 @@ class MetadataReader {
       while (true) {
         // Read the next string.
         std::string temp;
-        if (!Reader->readString(RemoteAddress(nameAddress), temp))
+        if (!Reader->readString(nameAddress, temp))
           return std::nullopt;
 
         // If we read an empty string, we're done.
@@ -2467,8 +2483,7 @@ class MetadataReader {
         return nullptr;
 
       // Move the address forward and add the next chunk.
-      currentAddress =
-        RemoteAddress(currentAddress.getAddressData() + chunk.size() + 1);
+      currentAddress = currentAddress + chunk.size() + 1;
       mangledName += std::move(chunk);
 
       // Scan through the mangled name to skip over symbolic references.
@@ -2502,7 +2517,7 @@ class MetadataReader {
       // We're done.
       break;
     }
-    return demangle(address.getAddressData(), mangledName, kind, dem);
+    return demangle(address, mangledName, kind, dem);
   }
 
   /// Read and demangle the name of an anonymous context.
@@ -2519,9 +2534,7 @@ class MetadataReader {
     auto mangledContextName = anonymousBuffer->getMangledContextName();
     auto mangledNameAddress = resolveRelativeField(contextRef,
                                                    mangledContextName->name);
-    return readMangledName(RemoteAddress(mangledNameAddress),
-                           MangledNameKind::Symbol,
-                           dem);
+    return readMangledName(mangledNameAddress, MangledNameKind::Symbol, dem);
   }
 
   /// If we have a context whose parent context is an anonymous context
@@ -2603,18 +2616,18 @@ class MetadataReader {
   /// Resolve a relative target protocol descriptor pointer, which uses
   /// the lowest bit to indicate an indirect vs. direct relative reference and
   /// the second lowest bit to indicate whether it is an Objective-C protocol.
-  template<typename Base>
-  StoredPointer resolveRelativeIndirectProtocol(
+  template <typename Base>
+  RemoteAddress resolveRelativeIndirectProtocol(
       RemoteRef<Base> descriptor,
       const RelativeTargetProtocolDescriptorPointer<Runtime> &protocol) {
     // Map the offset from within our local buffer to the remote address.
     auto distance = (intptr_t)&protocol - (intptr_t)descriptor.getLocalBuffer();
-    StoredPointer targetAddress(getAddress(descriptor) + distance);
+    RemoteAddress targetAddress(getAddress(descriptor) + distance);
 
     // Read the relative offset.
     int32_t relative;
-    if (!Reader->readInteger(RemoteAddress(targetAddress), &relative))
-      return StoredPointer();
+    if (!Reader->readInteger(targetAddress, &relative))
+      return RemoteAddress();
 
     // Collect and mask off the 'indirect' and 'isObjC' bits.
     bool indirect = relative & 1;
@@ -2625,15 +2638,14 @@ class MetadataReader {
     using SignedPointer = typename std::make_signed<StoredPointer>::type;
     auto signext = (SignedPointer)(int32_t)relative;
 
-    StoredPointer resultAddress = targetAddress + signext;
+    RemoteAddress resultAddress = targetAddress + signext;
 
     // Low bit set in the offset indicates that the offset leads to the absolute
     // address in memory.
     if (indirect) {
-      if (!Reader->readBytes(RemoteAddress(resultAddress),
-                             (uint8_t *)&resultAddress,
-                             sizeof(StoredPointer)))
-        return StoredPointer();
+      if (!Reader->template readRemoteAddress<StoredPointer>(resultAddress,
+                                                             resultAddress))
+        return RemoteAddress();
     }
 
     // Add back the Objective-C bit.
@@ -2756,9 +2768,7 @@ class MetadataReader {
         resolveRelativeField(descriptor, extensionBuffer->ExtendedContext);
 
       auto demangledExtendedContext =
-        readMangledName(RemoteAddress(extendedContextAddress),
-                        MangledNameKind::Type,
-                        dem);
+          readMangledName(extendedContextAddress, MangledNameKind::Type, dem);
       if (!demangledExtendedContext)
         return nullptr;
 
@@ -2807,8 +2817,7 @@ class MetadataReader {
           // Demangle the subject.
           auto subjectAddress = resolveRelativeField(descriptor, req.Param);
           swift::Demangle::NodePointer subject =
-              readMangledName(RemoteAddress(subjectAddress),
-                              MangledNameKind::Type, dem);
+              readMangledName(subjectAddress, MangledNameKind::Type, dem);
           if (!subject) {
             failed = true;
             break;
@@ -2818,8 +2827,9 @@ class MetadataReader {
           case GenericRequirementKind::Protocol: {
             auto protocolAddress =
               resolveRelativeIndirectProtocol(descriptor, req.Protocol);
-            auto protocol = readProtocol(protocolAddress, dem,
-                                         protocolResolver);
+            auto protocolRef =
+                RemoteTargetProtocolDescriptorRef<Runtime>(protocolAddress);
+            auto protocol = readProtocol(protocolRef, dem, protocolResolver);
             if (!protocol) {
               failed = true;
               break;
@@ -2839,8 +2849,7 @@ class MetadataReader {
             // Demangle the right-hand type.
             auto typeAddress = resolveRelativeField(descriptor, req.Type);
             swift::Demangle::NodePointer type =
-                readMangledName(RemoteAddress(typeAddress),
-                                MangledNameKind::Type, dem);
+                readMangledName(typeAddress, MangledNameKind::Type, dem);
             if (!type) {
               failed = true;
               break;
@@ -2868,11 +2877,11 @@ class MetadataReader {
             // address.
             auto distance =
               (intptr_t)&req.Layout - (intptr_t)descriptor.getLocalBuffer();
-            StoredPointer targetAddress(getAddress(descriptor) + distance);
+            RemoteAddress targetAddress(getAddress(descriptor) + distance);
 
             GenericRequirementLayoutKind kind;
-            if (!Reader->readBytes(RemoteAddress(targetAddress),
-                                   (uint8_t *)&kind, sizeof(kind))) {
+            if (!Reader->readBytes(targetAddress, (uint8_t *)&kind,
+                                   sizeof(kind))) {
               failed = true;
               break;
             }
@@ -2907,8 +2916,10 @@ class MetadataReader {
     case ContextDescriptorKind::Anonymous: {
       // Use the remote address to identify the anonymous context.
       char addressBuf[18];
+      RemoteAddress address(descriptor.getRemoteAddress());
+      address = Reader->resolveRemoteAddress(address).value_or(address);
       snprintf(addressBuf, sizeof(addressBuf), "$%" PRIx64,
-               (uint64_t)descriptor.getAddressData());
+               (uint64_t)descriptor.getRemoteAddress().getRawAddress());
       auto anonNode = dem.createNode(Node::Kind::AnonymousContext);
       CharVector addressStr;
       addressStr.append(addressBuf, dem);
@@ -2933,7 +2944,7 @@ class MetadataReader {
       auto nameAddress
         = resolveRelativeField(descriptor, moduleBuffer->Name);
       std::string moduleName;
-      if (!Reader->readString(RemoteAddress(nameAddress), moduleName))
+      if (!Reader->readString(nameAddress, moduleName))
         return nullptr;
 
       // The form of module contexts is a little different from other
@@ -3091,7 +3102,7 @@ class MetadataReader {
   }
 
 #if SWIFT_OBJC_INTEROP
-  std::string readObjCProtocolName(StoredPointer Address) {
+  std::string readObjCProtocolName(RemoteAddress Address) {
     auto Size = sizeof(TargetObjCProtocolPrefix<Runtime>);
     auto Buffer = (uint8_t *)malloc(Size);
     if (!Buffer)
@@ -3100,13 +3111,15 @@ class MetadataReader {
       free(Buffer);
     };
 
-    if (!Reader->readBytes(RemoteAddress(Address), Buffer, Size))
+    if (!Reader->readBytes(Address, Buffer, Size))
       return std::string();
 
     auto ProtocolDescriptor
       = reinterpret_cast<TargetObjCProtocolPrefix<Runtime> *>(Buffer);
+    auto NameAddress =
+        RemoteAddress(ProtocolDescriptor->Name, Address.getAddressSpace());
     std::string Name;
-    if (!Reader->readString(RemoteAddress(ProtocolDescriptor->Name), Name))
+    if (!Reader->readString(NameAddress, Name))
       return std::string();
 
     return Name;
@@ -3143,10 +3156,10 @@ class MetadataReader {
           if (numGenericArgs == 0)
             return {};
           --numGenericArgs;
-          
-          StoredPointer arg;
-          if (!Reader->readBytes(RemoteAddress(genericArgsAddr),
-                                 (uint8_t*)&arg, sizeof(arg))) {
+
+          RemoteAddress arg;
+          if (!Reader->template readRemoteAddress<StoredPointer>(
+                  genericArgsAddr, arg)) {
             return {};
           }
           genericArgsAddr += sizeof(StoredPointer);
@@ -3202,6 +3215,23 @@ class MetadataReader {
     if (!descriptor)
       return BuiltType();
 
+    // Make sure the kinds match, to catch bad data from not reading an actual
+    // metadata.
+    auto metadataKind = metadata.getLocalBuffer()->getKind();
+    auto descriptorKind = descriptor.getLocalBuffer()->getKind();
+    if (metadataKind == MetadataKind::Class &&
+        descriptorKind != ContextDescriptorKind::Class)
+      return BuiltType();
+    if (metadataKind == MetadataKind::Struct &&
+        descriptorKind != ContextDescriptorKind::Struct)
+      return BuiltType();
+    if (metadataKind == MetadataKind::Enum &&
+        descriptorKind != ContextDescriptorKind::Enum)
+      return BuiltType();
+    if (metadataKind == MetadataKind::Optional &&
+        descriptorKind != ContextDescriptorKind::Enum)
+      return BuiltType();
+
     // From that, attempt to resolve a nominal type.
     BuiltTypeDecl typeDecl = buildNominalTypeDecl(descriptor);
     if (!typeDecl)
@@ -3269,17 +3299,16 @@ class MetadataReader {
 
   /// Given that the remote process is running the non-fragile Apple runtime,
   /// grab the ro-data from a class pointer.
-  StoredPointer readObjCRODataPtr(StoredPointer classAddress) {
+  RemoteAddress readObjCRODataPtr(RemoteAddress classAddress) {
     // WARNING: the following algorithm works on current modern Apple
     // runtimes but is not actually ABI.  But it is pretty reliable.
 
 #if SWIFT_OBJC_INTEROP
-    StoredPointer dataPtr;
-    if (!Reader->readInteger(
-            RemoteAddress(classAddress +
-                          TargetClassMetadataObjCInterop::offsetToData()),
-            &dataPtr))
-      return StoredPointer();
+    RemoteAddress dataPtr;
+    if (!Reader->template readRemoteAddress<StoredPointer>(
+            classAddress + TargetClassMetadataObjCInterop::offsetToData(),
+            dataPtr))
+      return RemoteAddress();
 
     // Apply the data-pointer mask.
     // These values have been stolen from the runtime source.
@@ -3287,12 +3316,12 @@ class MetadataReader {
       (Runtime::PointerSize == 8 ? 0x00007ffffffffff8ULL : 0xfffffffcULL);
     dataPtr &= StoredPointer(DataPtrMask);
     if (!dataPtr)
-      return StoredPointer();
+      return RemoteAddress();
 
     // Read the flags, which is a 32-bit header on both formats.
     uint32_t flags;
-    if (!Reader->readInteger(RemoteAddress(dataPtr), &flags))
-      return StoredPointer();
+    if (!Reader->readInteger(dataPtr, &flags))
+      return RemoteAddress();
 
     // If the type is not realized, this is the RO-data.
     static constexpr uint32_t RO_REALIZED = 0x80000000U;
@@ -3303,22 +3332,22 @@ class MetadataReader {
     // well-known position within the RW-data.
     StoredSignedPointer signedDataPtr;
     static constexpr uint32_t OffsetToROPtr = 8;
-    if (!Reader->readInteger(RemoteAddress(dataPtr + OffsetToROPtr), &signedDataPtr))
-      return StoredPointer();
+    if (!Reader->readInteger(dataPtr + OffsetToROPtr, &signedDataPtr))
+      return RemoteAddress();
     dataPtr = stripSignedPointer(signedDataPtr);
 
     // Newer Objective-C runtimes implement a size optimization where the RO
     // field is a tagged union. If the low-bit is set, then the pointer needs
     // to be dereferenced once more to yield the real class_ro_t pointer.
     if (dataPtr & 1) {
-      if (!Reader->readInteger(RemoteAddress(dataPtr^1), &signedDataPtr))
-        return StoredPointer();
+      if (!Reader->readInteger(dataPtr ^ 1, &signedDataPtr))
+        return RemoteAddress();
       dataPtr = stripSignedPointer(signedDataPtr);
     }
 
     return dataPtr;
 #else
-    return StoredPointer();
+    return RemoteAddress();
 #endif
   }
 
@@ -3361,9 +3390,9 @@ class MetadataReader {
         tryFindAndReadSymbol(IsaIndexShift,
                              "objc_debug_indexed_isa_index_shift");
         tryFindSymbol(indexedClasses, "objc_indexed_classes");
-        IndexedClassesPointer = indexedClasses.getAddressData();
+        IndexedClassesPointer = indexedClasses;
         tryFindSymbol(indexedClassesCount, "objc_indexed_classes_count");
-        IndexedClassesCountPointer = indexedClassesCount.getAddressData();
+        IndexedClassesCountPointer = indexedClassesCount;
 
         return finish(IsaEncodingKind::Indexed);
       }
@@ -3429,8 +3458,8 @@ class MetadataReader {
                   "objc_debug_taggedpointer_classes");
     if (!TaggedPointerClassesAddr)
       finish(TaggedPointerEncodingKind::Error);
-    TaggedPointerClasses = TaggedPointerClassesAddr.getAddressData();
-    
+    TaggedPointerClasses = TaggedPointerClassesAddr;
+
     // Extended tagged pointers don't exist on older OSes. Handle those
     // by setting the variables to zero.
     tryFindAndReadSymbolWithDefault(TaggedPointerExtendedMask,
@@ -3445,15 +3474,12 @@ class MetadataReader {
     auto TaggedPointerExtendedClassesAddr =
       Reader->getSymbolAddress("objc_debug_taggedpointer_ext_classes");
     if (TaggedPointerExtendedClassesAddr)
-      TaggedPointerExtendedClasses =
-          TaggedPointerExtendedClassesAddr.getAddressData();
+      TaggedPointerExtendedClasses = TaggedPointerExtendedClassesAddr;
 
     // The tagged pointer obfuscator is not present on older OSes, in
     // which case we can treat it as zero.
     tryFindAndReadSymbolWithDefault(TaggedPointerObfuscator,
-                                    "objc_debug_taggedpointer_obfuscator",
-                                    0);
-    
+                                    "objc_debug_taggedpointer_obfuscator", 0);
 #   undef tryFindSymbol
 #   undef tryReadSymbol
 #   undef tryFindAndReadSymbol
diff --git a/include/swift/Remote/RemoteAddress.h b/include/swift/Remote/RemoteAddress.h
index 15c10aa23c216..5c1f0e2cc6eac 100644
--- a/include/swift/Remote/RemoteAddress.h
+++ b/include/swift/Remote/RemoteAddress.h
@@ -18,85 +18,265 @@
 #ifndef SWIFT_REMOTE_REMOTEADDRESS_H
 #define SWIFT_REMOTE_REMOTEADDRESS_H
 
+#include "swift/ABI/MetadataRef.h"
+#include "swift/Basic/RelativePointer.h"
+#include "llvm/ADT/DenseMapInfo.h"
+#include "llvm/ADT/Hashing.h"
+#include <cassert>
 #include <cstdint>
-#include <string>
+#include <functional>
+#include <iostream>
 #include <llvm/ADT/StringRef.h>
-#include <cassert>
+#include <ostream>
+#include <sstream>
+#include <string>
 
 namespace swift {
 namespace remote {
 
 /// An abstract address in the remote process's address space.
 class RemoteAddress {
-  uint64_t Data;
 public:
-  explicit RemoteAddress(const void *localPtr)
-    : Data(reinterpret_cast<uintptr_t>(localPtr)) {}
+  // The default address space, meaning the remote process address space.
+  static constexpr uint8_t DefaultAddressSpace = 0;
 
-  explicit RemoteAddress(uint64_t addressData) : Data(addressData) {}
+  explicit RemoteAddress(uint64_t addressData, uint8_t addressSpace)
+      : Data(addressData), AddressSpace(addressSpace) {}
 
-  explicit operator bool() const {
-    return Data != 0;
+  explicit RemoteAddress() {}
+
+  explicit operator bool() const { return Data != 0; }
+
+  bool operator==(const RemoteAddress rhs) const {
+    return Data == rhs.Data && AddressSpace == rhs.AddressSpace;
   }
 
-  template <class T>
-  const T *getLocalPointer() const {
-    return reinterpret_cast<const T*>(static_cast<uintptr_t>(Data));
+  bool operator!=(const RemoteAddress other) const {
+    return !operator==(other);
+  }
+
+  bool inRange(const RemoteAddress &begin, const RemoteAddress &end) const {
+    assert(begin.AddressSpace == end.AddressSpace &&
+           "Unexpected address spaces");
+    if (AddressSpace != begin.AddressSpace)
+      return false;
+    return begin <= *this && *this < end;
+  }
+
+  bool operator<(const RemoteAddress rhs) const {
+    assert(AddressSpace == rhs.AddressSpace &&
+           "Comparing remote addresses of different address spaces");
+    return Data < rhs.Data;
+  }
+
+  /// Less than operator to be used for ordering purposes. The default less than
+  /// operator asserts if the address spaces are different, this one takes it
+  /// into account to determine the order of the addresses.
+  bool orderedLessThan(const RemoteAddress rhs) const {
+    if (AddressSpace == rhs.AddressSpace)
+      return Data < rhs.Data;
+    return AddressSpace < rhs.AddressSpace;
   }
 
-  uint64_t getAddressData() const {
-    return Data;
+  bool operator<=(const RemoteAddress rhs) const {
+    assert(AddressSpace == rhs.AddressSpace &&
+           "Comparing remote addresses of different address spaces");
+    return Data <= rhs.Data;
   }
 
-  template<typename IntegerType>
-  RemoteAddress& operator+=(const IntegerType& rhs) {
+  /// Less than or equal operator to be used for ordering purposes. The default
+  /// less than or equal operator asserts if the address spaces are different,
+  /// this one takes it into account to determine the order of the addresses.
+  bool orderedLessThanOrEqual(const RemoteAddress rhs) const {
+    if (AddressSpace == rhs.AddressSpace)
+      return Data <= rhs.Data;
+    return AddressSpace <= rhs.AddressSpace;
+  }
+
+  bool operator>(const RemoteAddress &rhs) const {
+    assert(AddressSpace == rhs.AddressSpace &&
+           "Comparing remote addresses of different address spaces");
+    return Data > rhs.Data;
+  }
+
+  bool operator>=(const RemoteAddress &rhs) const { return Data >= rhs.Data; }
+
+  template <typename IntegerType>
+  RemoteAddress &operator+=(const IntegerType rhs) {
     Data += rhs;
     return *this;
   }
 
-  template<typename IntegerType>
-  friend RemoteAddress operator+(RemoteAddress lhs,
-                                 const IntegerType& rhs) {
-    return lhs += rhs;
+  template <typename IntegerType>
+  RemoteAddress operator+(const IntegerType &rhs) const {
+    return RemoteAddress(Data + rhs, getAddressSpace());
   }
+
+  template <typename IntegerType>
+  RemoteAddress operator-(const IntegerType &rhs) const {
+    return RemoteAddress(Data - rhs, getAddressSpace());
+  }
+
+  uint64_t operator-(const RemoteAddress &rhs) const {
+    assert(AddressSpace == rhs.AddressSpace &&
+           "Comparing remote addresses of different address spaces");
+    return Data - rhs.Data;
+  }
+
+  template <typename IntegerType>
+  RemoteAddress operator^(const IntegerType &rhs) const {
+    return RemoteAddress(Data ^ rhs, getAddressSpace());
+  }
+
+  template <class IntegerType>
+  RemoteAddress operator&(IntegerType other) const {
+    return RemoteAddress(Data & other, getAddressSpace());
+  }
+
+  template <typename IntegerType>
+  RemoteAddress &operator&=(const IntegerType rhs) {
+    Data &= rhs;
+    return *this;
+  }
+
+  template <typename IntegerType>
+  RemoteAddress &operator|=(const IntegerType rhs) {
+    Data |= rhs;
+    return *this;
+  }
+
+  template <typename IntegerType>
+  IntegerType operator>>(const IntegerType rhs) const {
+    return (IntegerType)Data >> rhs;
+  }
+
+  uint64_t getRawAddress() const { return Data; }
+
+  uint8_t getAddressSpace() const { return AddressSpace; }
+
+  template <class IntegerType>
+  RemoteAddress applyRelativeOffset(IntegerType offset) const {
+    auto atOffset = detail::applyRelativeOffset((const char *)Data, offset);
+    return RemoteAddress(atOffset, getAddressSpace());
+  }
+
+  template <typename T, bool Nullable, typename Offset>
+  RemoteAddress getRelative(
+      const RelativeDirectPointer<T, Nullable, Offset> *relative) const {
+    auto ptr = relative->getRelative((void *)Data);
+    return RemoteAddress((uint64_t)ptr, getAddressSpace());
+  }
+
+  template <class T>
+  const T *getLocalPointer() const {
+    return reinterpret_cast<const T *>(static_cast<uintptr_t>(Data));
+  }
+
+  std::string getDescription() const {
+    std::stringstream sstream;
+    // FIXME: this should print the address space too, but because Node can't
+    // carry the address space yet, comparing the strings produced by this type
+    // and a Node that carries an address would produce incorrect results.
+    // Revisit this once Node carries the address space.
+    sstream << std::hex << Data;
+    return sstream.str();
+  }
+
+  friend llvm::hash_code hash_value(const RemoteAddress &address) {
+    using llvm::hash_value;
+    return hash_value(address.Data);
+  }
+
+  friend struct std::hash<swift::remote::RemoteAddress>;
+
+private:
+  uint64_t Data = 0;
+  uint8_t AddressSpace = 0;
 };
 
 /// A symbolic relocated absolute pointer value.
 class RemoteAbsolutePointer {
-  /// The symbol name that the pointer refers to. Empty if the value is absolute.
+  /// The symbol name that the pointer refers to. Empty if only an absolute
+  /// address is available.
   std::string Symbol;
-  /// The offset from the symbol, or the resolved remote address if \c Symbol is empty.
-  int64_t Offset;
+  /// The offset from the symbol.
+  int64_t Offset = 0;
+  /// The resolved remote address.
+  RemoteAddress Address = RemoteAddress();
 
 public:
-  RemoteAbsolutePointer()
-    : Symbol(), Offset(0)
-  {}
-  
-  RemoteAbsolutePointer(std::nullptr_t)
-    : RemoteAbsolutePointer()
-  {}
-  
-  RemoteAbsolutePointer(llvm::StringRef Symbol, int64_t Offset)
-    : Symbol(Symbol), Offset(Offset)
-  {}
-  
-  bool isResolved() const { return Symbol.empty(); }
+  RemoteAbsolutePointer() = default;
+  RemoteAbsolutePointer(std::nullptr_t) : RemoteAbsolutePointer() {}
+
+  RemoteAbsolutePointer(llvm::StringRef Symbol, int64_t Offset,
+                        RemoteAddress Address)
+      : Symbol(Symbol), Offset(Offset), Address(Address) {}
+  RemoteAbsolutePointer(RemoteAddress Address) : Address(Address) {}
+
   llvm::StringRef getSymbol() const { return Symbol; }
   int64_t getOffset() const { return Offset; }
-  
-  RemoteAddress getResolvedAddress() const {
-    assert(isResolved());
-    return RemoteAddress(Offset);
-  }
-  
+
+  RemoteAddress getResolvedAddress() const { return Address; }
+
   explicit operator bool() const {
-    return Offset != 0 || !Symbol.empty();
+    return Address || !Symbol.empty();
   }
 };
 
+template <typename Runtime>
+class RemoteTargetProtocolDescriptorRef {
+  TargetProtocolDescriptorRef<Runtime> ProtocolRef;
+  RemoteAddress address;
+
+public:
+  RemoteTargetProtocolDescriptorRef(RemoteAddress address)
+      : ProtocolRef(address.getRawAddress()), address(address) {}
+
+  bool isObjC() const { return ProtocolRef.isObjC(); }
+
+  RemoteAddress getObjCProtocol() const {
+    auto pointer = ProtocolRef.getObjCProtocol();
+    return RemoteAddress(pointer, address.getAddressSpace());
+  }
+
+  RemoteAddress getSwiftProtocol() const {
+    auto pointer = ProtocolRef.getSwiftProtocol();
+    return RemoteAddress(pointer, address.getAddressSpace());
+  }
+};
 } // end namespace remote
 } // end namespace swift
 
-#endif // SWIFT_REMOTE_REMOTEADDRESS_H
+namespace std {
+template <>
+struct hash<swift::remote::RemoteAddress> {
+  size_t operator()(const swift::remote::RemoteAddress &address) const {
+    return llvm::hash_combine(address.Data, address.AddressSpace);
+  }
+};
+} // namespace std
 
+namespace llvm {
+template <>
+struct DenseMapInfo<swift::remote::RemoteAddress> {
+  static swift::remote::RemoteAddress getEmptyKey() {
+    return swift::remote::RemoteAddress(DenseMapInfo<uint64_t>::getEmptyKey(),
+                                        0);
+  }
+
+  static swift::remote::RemoteAddress getTombstoneKey() {
+    return swift::remote::RemoteAddress(
+        DenseMapInfo<uint64_t>::getTombstoneKey(), 0);
+  }
+
+  static unsigned getHashValue(swift::remote::RemoteAddress address) {
+    return std::hash<swift::remote::RemoteAddress>()(address);
+  }
+  static bool isEqual(swift::remote::RemoteAddress lhs,
+                      swift::remote::RemoteAddress rhs) {
+    return lhs == rhs;
+  }
+};
+} // namespace llvm
+
+#endif // SWIFT_REMOTE_REMOTEADDRESS_H
diff --git a/include/swift/RemoteInspection/ReflectionContext.h b/include/swift/RemoteInspection/ReflectionContext.h
index 98bfe4ea4e67a..329878e6356bb 100644
--- a/include/swift/RemoteInspection/ReflectionContext.h
+++ b/include/swift/RemoteInspection/ReflectionContext.h
@@ -18,12 +18,14 @@
 #ifndef SWIFT_REFLECTION_REFLECTIONCONTEXT_H
 #define SWIFT_REFLECTION_REFLECTIONCONTEXT_H
 
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/BinaryFormat/COFF.h"
-#include "llvm/BinaryFormat/MachO.h"
 #include "llvm/BinaryFormat/ELF.h"
+#include "llvm/BinaryFormat/MachO.h"
+#include "llvm/BinaryFormat/Wasm.h"
 #include "llvm/Object/COFF.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/Memory.h"
-#include "llvm/ADT/STLExtras.h"
 
 #include "swift/ABI/Enum.h"
 #include "swift/ABI/ObjectFile.h"
@@ -39,6 +41,8 @@
 #include "swift/RemoteInspection/TypeRefBuilder.h"
 #include "swift/Basic/Unreachable.h"
 
+#include <cstdint>
+#include <map>
 #include <set>
 #include <utility>
 #include <vector>
@@ -71,6 +75,11 @@
 #define HAS_DISPATCH_LOCK_IS_LOCKED 1
 #endif
 
+#define DEBUG_TYPE "reflection"
+#ifdef SWIFT_RUNTIME
+#undef LLVM_DEBUG
+#define LLVM_DEBUG(IGNORE)
+#endif
 namespace {
 
 template <unsigned PointerSize> struct MachOTraits;
@@ -122,8 +131,7 @@ class ReflectionContext
   using super::readMetadata;
   using super::readObjCClassName;
   using super::readResolvedPointerValue;
-  llvm::DenseMap<std::pair<typename super::StoredPointer,
-                           remote::TypeInfoProvider::IdType>,
+  llvm::DenseMap<std::pair<RemoteAddress, remote::TypeInfoProvider::IdType>,
                  const RecordTypeInfo *>
       Cache;
 
@@ -134,11 +142,13 @@ class ReflectionContext
   std::vector<std::tuple<RemoteAddress, RemoteAddress>> dataRanges;
 
   bool setupTargetPointers = false;
+  typename super::StoredPointer target_asyncTaskMetadata = 0;
   typename super::StoredPointer target_non_future_adapter = 0;
   typename super::StoredPointer target_future_adapter = 0;
   typename super::StoredPointer target_task_wait_throwing_resume_adapter = 0;
   typename super::StoredPointer target_task_future_wait_resume_adapter = 0;
   bool supportsPriorityEscalation = false;
+  typename super::StoredSize asyncTaskSize = 0;
 
 public:
   using super::getBuilder;
@@ -195,6 +205,7 @@ class ReflectionContext
     bool IsRunning;
     bool IsEnqueued;
     bool IsComplete;
+    bool IsSuspended;
 
     bool HasThreadPort;
     uint32_t ThreadPort;
@@ -253,17 +264,15 @@ class ReflectionContext
 
     // The layout of the executable is such that the commands immediately follow
     // the header.
-    auto CmdStartAddress =
-        RemoteAddress(ImageStart.getAddressData() + sizeof(typename T::Header));
+    auto CmdStartAddress = ImageStart + sizeof(typename T::Header);
     uint32_t SegmentCmdHdrSize = sizeof(typename T::SegmentCmd);
     uint64_t Offset = 0;
 
     // Find the __TEXT segment.
     typename T::SegmentCmd *TextCommand = nullptr;
     for (unsigned I = 0; I < NumCommands; ++I) {
-      auto CmdBuf = this->getReader().readBytes(
-          RemoteAddress(CmdStartAddress.getAddressData() + Offset),
-          SegmentCmdHdrSize);
+      auto CmdBuf = this->getReader().readBytes(CmdStartAddress + Offset,
+                                                SegmentCmdHdrSize);
       if (!CmdBuf)
         return {};
       auto CmdHdr = reinterpret_cast<typename T::SegmentCmd *>(CmdBuf.get());
@@ -280,26 +289,24 @@ class ReflectionContext
       return {};
 
    // Find the load command offset.
-    auto loadCmdOffset = ImageStart.getAddressData() + Offset + sizeof(typename T::Header);
+    auto loadCmdOffset = ImageStart + Offset + sizeof(typename T::Header);
 
     // Read the load command.
-    auto LoadCmdAddress = reinterpret_cast<const char *>(loadCmdOffset);
     auto LoadCmdBuf = this->getReader().readBytes(
-        RemoteAddress(LoadCmdAddress), sizeof(typename T::SegmentCmd));
+        loadCmdOffset, sizeof(typename T::SegmentCmd));
     if (!LoadCmdBuf)
       return {};
     auto LoadCmd = reinterpret_cast<typename T::SegmentCmd *>(LoadCmdBuf.get());
 
     // The sections start immediately after the load command.
     unsigned NumSect = LoadCmd->nsects;
-    auto SectAddress = reinterpret_cast<const char *>(loadCmdOffset) +
-                       sizeof(typename T::SegmentCmd);
+    auto SectAddress = loadCmdOffset + sizeof(typename T::SegmentCmd);
     auto Sections = this->getReader().readBytes(
-        RemoteAddress(SectAddress), NumSect * sizeof(typename T::Section));
+        SectAddress, NumSect * sizeof(typename T::Section));
     if (!Sections)
       return {};
 
-    auto Slide = ImageStart.getAddressData() - TextCommand->vmaddr;
+    auto Slide = ImageStart - TextCommand->vmaddr;
     auto SectionsBuf = reinterpret_cast<const char *>(Sections.get());
 
     auto findMachOSectionByName = [&](llvm::StringRef Name)
@@ -310,9 +317,9 @@ class ReflectionContext
         if (strncmp(S->sectname, Name.data(), sizeof(S->sectname)) != 0)
           continue;
 
-        auto RemoteSecStart = S->addr + Slide;
+        auto RemoteSecStart = Slide + S->addr;
         auto LocalSectBuf =
-            this->getReader().readBytes(RemoteAddress(RemoteSecStart), S->size);
+            this->getReader().readBytes(RemoteSecStart, S->size);
         if (!LocalSectBuf)
           return {nullptr, 0};
 
@@ -365,14 +372,12 @@ class ReflectionContext
 
     auto TextSegmentStart = Slide + TextCommand->vmaddr;
     auto TextSegmentEnd = TextSegmentStart + TextCommand->vmsize;
-    textRanges.push_back(std::make_tuple(RemoteAddress(TextSegmentStart),
-                                         RemoteAddress(TextSegmentEnd)));
+    textRanges.push_back(std::make_tuple(TextSegmentStart, TextSegmentEnd));
 
     // Find the __DATA segments.
     for (unsigned I = 0; I < NumCommands; ++I) {
-      auto CmdBuf = this->getReader().readBytes(
-          RemoteAddress(CmdStartAddress.getAddressData() + Offset),
-          SegmentCmdHdrSize);
+      auto CmdBuf = this->getReader().readBytes(CmdStartAddress + Offset,
+                                                SegmentCmdHdrSize);
       if (!CmdBuf)
         return {};
       auto CmdHdr = reinterpret_cast<typename T::SegmentCmd *>(CmdBuf.get());
@@ -381,10 +386,9 @@ class ReflectionContext
           strncmp(CmdHdr->segname, "__AUTH", 6) == 0) {
         auto DataSegmentStart = Slide + CmdHdr->vmaddr;
         auto DataSegmentEnd = DataSegmentStart + CmdHdr->vmsize;
-        assert(DataSegmentStart > ImageStart.getAddressData() &&
+        assert(DataSegmentStart > ImageStart &&
                "invalid range for __DATA/__AUTH");
-        dataRanges.push_back(std::make_tuple(RemoteAddress(DataSegmentStart),
-                                             RemoteAddress(DataSegmentEnd)));
+        dataRanges.push_back(std::make_tuple(DataSegmentStart, DataSegmentEnd));
       }
       Offset += CmdHdr->cmdsize;
     }
@@ -404,12 +408,11 @@ class ReflectionContext
       return {};
     auto DOSHdr =
         reinterpret_cast<const llvm::object::dos_header *>(DOSHdrBuf.get());
-    auto COFFFileHdrAddr = ImageStart.getAddressData() +
-                           DOSHdr->AddressOfNewExeHeader +
+    auto COFFFileHdrAddr = ImageStart + DOSHdr->AddressOfNewExeHeader +
                            sizeof(llvm::COFF::PEMagic);
 
     auto COFFFileHdrBuf = this->getReader().readBytes(
-        RemoteAddress(COFFFileHdrAddr), sizeof(llvm::object::coff_file_header));
+        COFFFileHdrAddr, sizeof(llvm::object::coff_file_header));
     if (!COFFFileHdrBuf)
       return {};
     auto COFFFileHdr = reinterpret_cast<const llvm::object::coff_file_header *>(
@@ -419,7 +422,7 @@ class ReflectionContext
                             sizeof(llvm::object::coff_file_header) +
                             COFFFileHdr->SizeOfOptionalHeader;
     auto SectionTableBuf = this->getReader().readBytes(
-        RemoteAddress(SectionTableAddr),
+        SectionTableAddr,
         sizeof(llvm::object::coff_section) * COFFFileHdr->NumberOfSections);
     if (!SectionTableBuf)
       return {};
@@ -437,9 +440,8 @@ class ReflectionContext
                 : llvm::StringRef(COFFSec->Name, llvm::COFF::NameSize);
         if (SectionName != Name)
           continue;
-        auto Addr = ImageStart.getAddressData() + COFFSec->VirtualAddress;
-        auto Buf = this->getReader().readBytes(RemoteAddress(Addr),
-                                               COFFSec->VirtualSize);
+        auto Addr = ImageStart + COFFSec->VirtualAddress;
+        auto Buf = this->getReader().readBytes(Addr, COFFSec->VirtualSize);
         if (!Buf)
           return {nullptr, 0};
         auto BufStart = Buf.get();
@@ -509,10 +511,9 @@ class ReflectionContext
 
     auto DOSHdr = reinterpret_cast<const llvm::object::dos_header *>(Buf.get());
 
-    auto PEHeaderAddress =
-        ImageStart.getAddressData() + DOSHdr->AddressOfNewExeHeader;
+    auto PEHeaderAddress = ImageStart + DOSHdr->AddressOfNewExeHeader;
 
-    Buf = this->getReader().readBytes(RemoteAddress(PEHeaderAddress),
+    Buf = this->getReader().readBytes(PEHeaderAddress,
                                       sizeof(llvm::COFF::PEMagic));
     if (!Buf)
       return {};
@@ -632,6 +633,9 @@ class ReflectionContext
             return {nullptr, 0};
           // Now for all the sections, find their name.
           for (const typename T::Section *Hdr : SecHdrVec) {
+            // Skip unused headers
+            if (Hdr->sh_type == llvm::ELF::SHT_NULL)
+              continue;
             uint32_t Offset = Hdr->sh_name;
             const char *Start = (const char *)StrTab + Offset;
             uint64_t StringSize = strnlen(Start, StrTabSize - Offset);
@@ -644,8 +648,7 @@ class ReflectionContext
               continue;
             if (Retained != bool(Hdr->sh_flags & llvm::ELF::SHF_GNU_RETAIN))
               continue;
-            RemoteAddress SecStart =
-                RemoteAddress(ImageStart.getAddressData() + Hdr->sh_addr);
+            RemoteAddress SecStart = ImageStart + Hdr->sh_addr;
             auto SecSize = Hdr->sh_size;
             MemoryReader::ReadBytesResult SecBuf;
             if (FileBuffer.has_value()) {
@@ -667,8 +670,7 @@ class ReflectionContext
             }
             if (!SecBuf)
               return {nullptr, 0};
-            auto SecContents =
-                RemoteRef<void>(SecStart.getAddressData(), SecBuf.get());
+            auto SecContents = RemoteRef<void>(SecStart, SecBuf.get());
             savedBuffers.push_back(std::move(SecBuf));
             return {SecContents, SecSize};
           }
@@ -805,6 +807,297 @@ class ReflectionContext
     }
   }
 
+  /// Parses metadata information from a WebAssembly image.
+  ///
+  ///
+  /// \param[in] ImageStart
+  ///     A remote address pointing to the start of the image in the running
+  ///     process.
+  ///
+  /// \param[in] FileBuffer
+  ///     A buffer which contains the contents of the image's file
+  ///     in disk. If missing, all the information will be read using the
+  ///     instance's memory reader.
+  ///
+  /// \return The newly added reflection info ID if successful, \b std::nullopt
+  ///     otherwise.
+  std::optional<uint32_t>
+  readWasm(RemoteAddress ImageStart,
+           std::optional<llvm::sys::MemoryBlock> FileBuffer,
+           llvm::SmallVector<llvm::StringRef, 1> PotentialModuleNames) {
+    /// A WASM data segment. The reflection metadata "sections" are DATA
+    /// segments.
+    struct Segment {
+      RemoteAddress remoteAddr;
+      uint64_t offset;
+      uint64_t size;
+    };
+    std::map<std::string, Segment> sections;
+    std::vector<Segment> segments;
+    auto &reader = getReader();
+    RemoteAddress cursor = ImageStart;
+    cursor += sizeof(llvm::wasm::WasmMagic) + sizeof(llvm::wasm::WasmVersion);
+
+    /// Decode one byte and move the cursor.
+    auto decodeU8 = [&reader, &cursor](uint8_t &b) -> bool {
+      if (!reader.readInteger(cursor, 1, &b))
+        return false;
+      cursor += 1;
+      return true;
+    };
+
+    /// Decode 32-bit ULEB constants.
+    auto decodeULEB32 = [&](uint32_t &val) -> bool {
+      uint64_t result = 0;
+      uint8_t b;
+      for (uint8_t n = 0; n < 5; ++n) {
+        if (!decodeU8(b))
+          return false;
+        result |= (b & ~(1 << 7)) << 7 * n;
+        if ((b & (1 << 7)) == 0)
+          break;
+      }
+      if (result > std::numeric_limits<uint32_t>::max())
+        return false;
+      memcpy(&val, &result, 4);
+      return true;
+    };
+
+    /// Decode a string.
+    auto decodeString = [&](std::string &str) -> bool {
+      uint32_t len;
+      if (!decodeULEB32(len))
+        return false;
+      auto chars = reader.readBytes(cursor, len);
+      if (!chars)
+        return false;
+      str = std::string((const char *)chars.get(), len);
+      cursor += len;
+      chars.release();
+      return true;
+    };
+
+    /// Decode one section header.
+    auto decodeSection = [&]() -> bool {
+      uint8_t sectionID;
+      if (!decodeU8(sectionID))
+        return false;
+
+      if (sectionID > llvm::wasm::WASM_SEC_LAST_KNOWN)
+        return false;
+
+      uint32_t payloadLen;
+      if (!decodeULEB32(payloadLen))
+        return false;
+      RemoteAddress payloadStart = cursor;
+      std::string sectName;
+      if (sectionID == llvm::wasm::WASM_SEC_CUSTOM) {
+        if (!decodeString(sectName))
+          return false;
+        RemoteAddress sectionStart = cursor;
+        sections.insert(
+            {sectName, {cursor, 0, payloadLen - (sectionStart - cursor)}});
+      } else {
+        sectName = llvm::wasm::sectionTypeToString(sectionID);
+        sections.insert({sectName, {cursor, 0, payloadLen}});
+      }
+      LLVM_DEBUG(llvm::dbgs()
+                 << "section " << sectName << " size=" << payloadLen << "\n");
+
+      cursor = payloadStart + payloadLen;
+      return true;
+    };
+
+    // Decode the DATA segments.
+    auto decodeData = [&](uint64_t sectLength) -> bool {
+      RemoteAddress start = cursor;
+      RemoteAddress end = start + sectLength;
+      uint32_t count;
+
+      auto decodeActiveSegmentOffset = [&]() -> std::optional<uint32_t> {
+        uint32_t offset = 0;
+        while (true) {
+          uint8_t b;
+          if (!decodeU8(b))
+            return {};
+
+          if (b == llvm::wasm::WASM_OPCODE_I32_CONST) {
+            if (!decodeULEB32(offset)) // FIXME: Actually an SLEB.
+              return {};
+          } else if (b == llvm::wasm::WASM_OPCODE_END) {
+            break;
+          } else {
+            // Unhandled opcode.
+            return {};
+          }
+        }
+        return offset;
+      };
+
+      if (!decodeULEB32(count))
+        return false;
+      // Parse the segment header.
+      for (uint32_t i = 0; i < count && cursor < end; ++i) {
+        uint32_t flags;
+        uint32_t offset = 0;
+        if (!decodeULEB32(flags))
+          return false;
+        if ((flags & 2) == 2) {
+          uint32_t memidx;
+          if (!decodeULEB32(memidx))
+            return false;
+        }
+        if ((flags & 1) == 0) {
+          auto offsOrErr = decodeActiveSegmentOffset();
+          if (!offsOrErr)
+            return false;
+          offset = *offsOrErr;
+        }
+        uint32_t size;
+        if (!decodeULEB32(size))
+          return false;
+        LLVM_DEBUG(llvm::dbgs()
+                   << "Segment[" << i << "]: flags=" << flags
+                   << " offset=" << offset << " size=" << size << "\n");
+        segments.push_back({cursor, offset, size});
+        cursor += size;
+      }
+      return true;
+    };
+    // Decode the NAMES table pointing to the DATA segments.
+    auto decodeNames = [&](uint64_t sectLength) -> bool {
+      RemoteAddress start = cursor;
+      RemoteAddress end = start + sectLength;
+      while (cursor < end) {
+        uint8_t type;
+        if (!decodeU8(type))
+          return false;
+        uint32_t len;
+        if (!decodeULEB32(len))
+          return false;
+        if (type == llvm::wasm::WASM_NAMES_DATA_SEGMENT) {
+          uint32_t count;
+          if (!decodeULEB32(count))
+            return false;
+          for (uint32_t i = 0; i < count; ++i) {
+            uint32_t idx;
+            if (!decodeULEB32(idx))
+              return false;
+            std::string sectName;
+            if (!decodeString(sectName))
+              return false;
+            if (idx >= segments.size())
+              return false;
+            LLVM_DEBUG(llvm::dbgs() << sectName << ": " << idx << "\n");
+            sections.insert({sectName, segments[idx]});
+          }
+        }
+        cursor += len;
+      }
+      return true;
+    };
+    // Decode the LINK section of object files.
+    auto decodeLinking = [&](RemoteAddress dataStart,
+                             uint64_t sectLength) -> bool {
+      RemoteAddress start = cursor;
+      RemoteAddress end = start + sectLength;
+
+      uint32_t version;
+      if (!decodeULEB32(version) || version != 2)
+        return false;
+      while (cursor < end) {
+        uint8_t type;
+        if (!decodeU8(type))
+          return false;
+        uint32_t len;
+        if (!decodeULEB32(len))
+          return false;
+        if (type == llvm::wasm::WASM_SEGMENT_INFO) {
+          uint32_t count;
+          if (!decodeULEB32(count))
+            return false;
+          for (uint32_t idx = 0; idx < count; ++idx) {
+            std::string sectName;
+            if (!decodeString(sectName))
+              return false;
+            uint32_t align;
+            if (!decodeULEB32(align))
+              return false;
+            uint32_t flags;
+            if (!decodeULEB32(flags))
+              return false;
+            LLVM_DEBUG(llvm::dbgs() << sectName << ": " << idx << "\n");
+            sections.insert({sectName, segments[idx]});
+          }
+        }
+        cursor += len;
+      }
+      return true;
+    };
+
+    while (decodeSection()) {
+    };
+    auto dataSect = sections.find("DATA");
+    if (dataSect == sections.end())
+      return false;
+
+    auto [dataStart, _, dataLength] = dataSect->second;
+    cursor = dataStart;
+    if (!decodeData(dataLength))
+      return false;
+
+    auto nameSect = sections.find("name");
+    if (nameSect != sections.end()) {
+      cursor = nameSect->second.remoteAddr;
+      if (!decodeNames(nameSect->second.size))
+        return false;
+    } else {
+      // This may be an object file?
+      auto linkingSect = sections.find("linking");
+      if (linkingSect == sections.end())
+        return false;
+      cursor = linkingSect->second.remoteAddr;
+      if (!decodeLinking(dataStart, linkingSect->second.size))
+        return false;
+    }
+
+    // Find reflection sections within the data section segments.
+    auto lookup =
+        [&](const std::string &name) -> std::pair<RemoteRef<void>, uint64_t> {
+      auto sectionIt = sections.find(name);
+      if (sectionIt == sections.end())
+        return {{}, 0};
+      auto &section = sectionIt->second;
+      RemoteAddress mappedSectionStart(0 + section.offset,
+                                       RemoteAddress::DefaultAddressSpace);
+      auto secBuf = reader.readBytes(section.remoteAddr, section.size);
+      auto secContents = RemoteRef<void>(mappedSectionStart, secBuf.get());
+      savedBuffers.push_back(std::move(secBuf));
+      LLVM_DEBUG(llvm::dbgs() << name << " @ " << section.offset << "\n");
+      return {secContents, section.size};
+    };
+
+    auto FieldMdSec = lookup("swift5_fieldmd");
+    auto AssocTySec = lookup("swift5_assocty");
+    auto BuiltinTySec = lookup("swift5_builtin");
+    auto CaptureSec = lookup("swift5_capture");
+    auto TypeRefMdSec = lookup("swift5_typeref");
+    auto ReflStrMdSec = lookup("swift5_reflstr");
+    auto ConformMdSec = lookup("swift5_protocol_conformances");
+    auto MPEnumMdSec = lookup("swift5_mpenum");
+
+    ReflectionInfo info = {{FieldMdSec.first, FieldMdSec.second},
+                           {AssocTySec.first, AssocTySec.second},
+                           {BuiltinTySec.first, BuiltinTySec.second},
+                           {CaptureSec.first, CaptureSec.second},
+                           {TypeRefMdSec.first, TypeRefMdSec.second},
+                           {ReflStrMdSec.first, ReflStrMdSec.second},
+                           {ConformMdSec.first, ConformMdSec.second},
+                           {MPEnumMdSec.first, MPEnumMdSec.second},
+                           PotentialModuleNames};
+    return addReflectionInfo(info);
+  }
+
   /// On success returns the ID of the newly registered Reflection Info.
   std::optional<uint32_t>
   addImage(RemoteAddress ImageStart,
@@ -833,7 +1126,6 @@ class ReflectionContext
       return readPECOFF(ImageStart, PotentialModuleNames);
     }
 
-
     // ELF.
     if (MagicBytes[0] == llvm::ELF::ElfMagic[0]
         && MagicBytes[1] == llvm::ELF::ElfMagic[1]
@@ -843,6 +1135,14 @@ class ReflectionContext
                      PotentialModuleNames);
     }
 
+    // WASM.
+    if (MagicBytes[0] == llvm::wasm::WasmMagic[0] &&
+        MagicBytes[1] == llvm::wasm::WasmMagic[1] &&
+        MagicBytes[2] == llvm::wasm::WasmMagic[2] &&
+        MagicBytes[3] == llvm::wasm::WasmMagic[3]) {
+      return readWasm(ImageStart, std::optional<llvm::sys::MemoryBlock>(),
+                      PotentialModuleNames);
+    }
     // We don't recognize the format.
     return std::nullopt;
   }
@@ -901,10 +1201,10 @@ class ReflectionContext
   }
 
   bool ownsObject(RemoteAddress ObjectAddress) {
-    auto MetadataAddress = readMetadataFromInstance(ObjectAddress.getAddressData());
+    auto MetadataAddress = readMetadataFromInstance(ObjectAddress);
     if (!MetadataAddress)
       return true;
-    return ownsAddress(RemoteAddress(*MetadataAddress));
+    return ownsAddress(*MetadataAddress);
   }
 
   /// Returns true if the address falls within the given address ranges.
@@ -914,8 +1214,7 @@ class ReflectionContext
     for (auto Range : ranges) {
       auto Start = std::get<0>(Range);
       auto End = std::get<1>(Range);
-      if (Start.getAddressData() <= Address.getAddressData()
-          && Address.getAddressData() < End.getAddressData())
+      if (Address.inRange(Start, End))
         return true;
     }
 
@@ -937,10 +1236,10 @@ class ReflectionContext
       // This is usually called on a Metadata address which might have been
       // on the heap. Try reading it and looking up its type context descriptor
       // instead.
-      if (auto Metadata = readMetadata(Address.getAddressData()))
+      if (auto Metadata = readMetadata(Address))
         if (auto DescriptorAddress =
             super::readAddressOfNominalTypeDescriptor(Metadata, true))
-          if (ownsAddress(RemoteAddress(DescriptorAddress), textRanges))
+          if (ownsAddress(DescriptorAddress, textRanges))
             return true;
     }
     return false;
@@ -948,17 +1247,18 @@ class ReflectionContext
 
   /// Returns the address of the nominal type descriptor given a metadata
   /// address.
-  StoredPointer nominalTypeDescriptorFromMetadata(StoredPointer MetadataAddress) {
+  RemoteAddress
+  nominalTypeDescriptorFromMetadata(RemoteAddress MetadataAddress) {
     auto Metadata = readMetadata(MetadataAddress);
     if (!Metadata)
-      return 0;
+      return RemoteAddress();
     return super::readAddressOfNominalTypeDescriptor(Metadata, true);
   }
 
   /// Return a description of the layout of a class instance with the given
   /// metadata as its isa pointer.
   const RecordTypeInfo *
-  getMetadataTypeInfo(StoredPointer MetadataAddress,
+  getMetadataTypeInfo(RemoteAddress MetadataAddress,
                       remote::TypeInfoProvider *ExternalTypeInfo) {
     // See if we cached the layout already
     auto ExternalTypeInfoId = ExternalTypeInfo ? ExternalTypeInfo->getId() : 0;
@@ -999,7 +1299,7 @@ class ReflectionContext
   /// Return a description of the layout of a class instance with the given
   /// metadata as its isa pointer.
   const TypeInfo *
-  getInstanceTypeInfo(StoredPointer ObjectAddress,
+  getInstanceTypeInfo(RemoteAddress ObjectAddress,
                       remote::TypeInfoProvider *ExternalTypeInfo) {
     auto MetadataAddress = readMetadataFromInstance(ObjectAddress);
     if (!MetadataAddress)
@@ -1017,7 +1317,7 @@ class ReflectionContext
       auto CDAddr = this->readCaptureDescriptorFromMetadata(*MetadataAddress);
       if (!CDAddr)
         return nullptr;
-      if (!CDAddr->isResolved())
+      if (!CDAddr->getResolvedAddress())
         return nullptr;
 
       // FIXME: Non-generic SIL boxes also use the HeapLocalVariable metadata
@@ -1026,8 +1326,7 @@ class ReflectionContext
       //
       // Non-generic SIL boxes share metadata among types with compatible
       // layout, but we need some way to get an outgoing pointer map for them.
-      auto CD = getBuilder().getCaptureDescriptor(
-                                CDAddr->getResolvedAddress().getAddressData());
+      auto CD = getBuilder().getCaptureDescriptor(CDAddr->getResolvedAddress());
       if (CD == nullptr)
         return nullptr;
 
@@ -1042,8 +1341,9 @@ class ReflectionContext
       if (auto Meta = readMetadata(*MetadataAddress)) {
         if (auto *GenericHeapMeta = cast<TargetGenericBoxHeapMetadata<Runtime>>(
                 Meta.getLocalBuffer())) {
-          auto MetadataAddress = GenericHeapMeta->BoxedType;
-          auto TR = readTypeFromMetadata(MetadataAddress);
+          auto BoxedTypeAddress = RemoteAddress(
+              GenericHeapMeta->BoxedType, ObjectAddress.getAddressSpace());
+          auto TR = readTypeFromMetadata(BoxedTypeAddress);
           return getTypeInfo(TR, ExternalTypeInfo);
         }
       }
@@ -1061,8 +1361,7 @@ class ReflectionContext
 
   std::optional<std::pair<const TypeRef *, RemoteAddress>>
   getDynamicTypeAndAddressClassExistential(RemoteAddress ExistentialAddress) {
-    auto PointerValue =
-        readResolvedPointerValue(ExistentialAddress.getAddressData());
+    auto PointerValue = readResolvedPointerValue(ExistentialAddress);
     if (!PointerValue)
       return {};
     auto Result = readMetadataFromInstance(*PointerValue);
@@ -1071,7 +1370,7 @@ class ReflectionContext
     auto TypeResult = readTypeFromMetadata(Result.value());
     if (!TypeResult)
       return {};
-    return {{std::move(TypeResult), RemoteAddress(*PointerValue)}};
+    return {{std::move(TypeResult), *PointerValue}};
   }
 
   std::optional<std::pair<const TypeRef *, RemoteAddress>>
@@ -1081,8 +1380,7 @@ class ReflectionContext
     if (!Result)
       return {};
 
-    auto TypeResult =
-        readTypeFromMetadata(Result->MetadataAddress.getAddressData());
+    auto TypeResult = readTypeFromMetadata(Result->MetadataAddress);
     if (!TypeResult)
       return {};
 
@@ -1098,8 +1396,7 @@ class ReflectionContext
     if (!Result)
       return {};
 
-    auto TypeResult =
-        readTypeFromMetadata(Result->MetadataAddress.getAddressData());
+    auto TypeResult = readTypeFromMetadata(Result->MetadataAddress);
     if (!TypeResult)
       return {};
     return {{std::move(TypeResult), Result->PayloadAddress}};
@@ -1136,8 +1433,7 @@ class ReflectionContext
       if (!OptMetaAndValue)
         return false;
 
-      auto InstanceTR = readTypeFromMetadata(
-          OptMetaAndValue->MetadataAddress.getAddressData());
+      auto InstanceTR = readTypeFromMetadata(OptMetaAndValue->MetadataAddress);
       if (!InstanceTR)
         return false;
 
@@ -1153,8 +1449,7 @@ class ReflectionContext
 
       // FIXME: Check third value, 'IsBridgedError'
 
-      auto InstanceTR = readTypeFromMetadata(
-          OptMetaAndValue->MetadataAddress.getAddressData());
+      auto InstanceTR = readTypeFromMetadata(OptMetaAndValue->MetadataAddress);
       if (!InstanceTR)
         return false;
 
@@ -1189,10 +1484,10 @@ class ReflectionContext
     };
 
     auto DereferenceAndSet = [&](RemoteAddress &Address) {
-      auto PointerValue = readResolvedPointerValue(Address.getAddressData());
+      auto PointerValue = readResolvedPointerValue(Address);
       if (!PointerValue)
         return false;
-      Address = RemoteAddress(*PointerValue);
+      Address = *PointerValue;
       return true;
     };
 
@@ -1274,6 +1569,15 @@ class ReflectionContext
     }
   }
 
+  llvm::Expected<const TypeInfo &>
+  getTypeInfo(const TypeRef &TR, remote::TypeInfoProvider *ExternalTypeInfo) {
+    auto &TC = getBuilder().getTypeConverter();
+    const TypeInfo *TI = TC.getTypeInfo(&TR, ExternalTypeInfo);
+    if (!TI)
+      return llvm::createStringError(TC.takeLastError());
+    return *TI;
+  }
+  
   /// Given a typeref, attempt to calculate the unaligned start of this
   /// instance's fields. For example, for a type without a superclass, the start
   /// of the instance fields would after the word for the isa pointer and the
@@ -1320,7 +1624,7 @@ class ReflectionContext
     return dyn_cast_or_null<const RecordTypeInfo>(TypeInfo);
   }
 
-  bool metadataIsActor(StoredPointer MetadataAddress) {
+  bool metadataIsActor(RemoteAddress MetadataAddress) {
     auto Metadata = readMetadata(MetadataAddress);
     if (!Metadata)
       return false;
@@ -1333,12 +1637,11 @@ class ReflectionContext
         super::readAddressOfNominalTypeDescriptor(Metadata);
     if (!DescriptorAddress)
       return false;
-    if (!ownsAddress(RemoteAddress(DescriptorAddress), textRanges))
+    if (!ownsAddress(DescriptorAddress, textRanges))
       return false;
 
-    auto DescriptorBytes =
-        getReader().readBytes(RemoteAddress(DescriptorAddress),
-                              sizeof(TargetTypeContextDescriptor<Runtime>));
+    auto DescriptorBytes = getReader().readBytes(
+        DescriptorAddress, sizeof(TargetTypeContextDescriptor<Runtime>));
     if (!DescriptorBytes)
       return false;
     auto Descriptor =
@@ -1349,12 +1652,13 @@ class ReflectionContext
 
   /// Iterate the protocol conformance cache tree rooted at NodePtr, calling
   /// Call with the type and protocol in each node.
-  void iterateConformanceTree(StoredPointer NodePtr,
-    std::function<void(StoredPointer Type, StoredPointer Proto)> Call) {
+  void iterateConformanceTree(
+      RemoteAddress NodePtr,
+      std::function<void(RemoteAddress Type, RemoteAddress Proto)> Call) {
     if (!NodePtr)
       return;
-    auto NodeBytes = getReader().readBytes(RemoteAddress(NodePtr),
-                                           sizeof(ConformanceNode<Runtime>));
+    auto NodeBytes =
+        getReader().readBytes(NodePtr, sizeof(ConformanceNode<Runtime>));
     if (!NodeBytes)
       return;
     auto NodeData =
@@ -1366,8 +1670,8 @@ class ReflectionContext
 
   void IterateConformanceTable(
       RemoteAddress ConformancesPtr,
-      std::function<void(StoredPointer Type, StoredPointer Proto)> Call) {
-    auto MapBytes = getReader().readBytes(RemoteAddress(ConformancesPtr),
+      std::function<void(RemoteAddress Type, RemoteAddress Proto)> Call) {
+    auto MapBytes = getReader().readBytes(ConformancesPtr,
                                           sizeof(ConcurrentHashMap<Runtime>));
     if (!MapBytes)
       return;
@@ -1377,8 +1681,9 @@ class ReflectionContext
     auto Count = MapData->ElementCount;
     auto Size = Count * sizeof(ConformanceCacheEntry<Runtime>) + sizeof(StoredPointer);
 
-    auto ElementsBytes =
-        getReader().readBytes(RemoteAddress(MapData->Elements), Size);
+    auto ElementsBytes = getReader().readBytes(
+        RemoteAddress(MapData->Elements, ConformancesPtr.getAddressSpace()),
+        Size);
     if (!ElementsBytes)
       return;
     auto ElementsData =
@@ -1387,7 +1692,8 @@ class ReflectionContext
 
     for (StoredSize i = 0; i < Count; i++) {
       auto &Element = ElementsData[i];
-      Call(Element.Type, Element.Proto);
+      Call(RemoteAddress(Element.Type, ConformancesPtr.getAddressSpace()),
+           stripSignedPointer(Element.Proto));
     }
   }
 
@@ -1395,7 +1701,7 @@ class ReflectionContext
   /// with the type and protocol of each conformance. Returns None on success,
   /// and a string describing the error on failure.
   std::optional<std::string> iterateConformances(
-      std::function<void(StoredPointer Type, StoredPointer Proto)> Call) {
+      std::function<void(RemoteAddress Type, RemoteAddress Proto)> Call) {
     std::string ConformancesPointerName =
         "_swift_debug_protocolConformanceStatePointer";
     auto ConformancesAddrAddr =
@@ -1417,15 +1723,15 @@ class ReflectionContext
   StoredPointer allocationMetadataPointer(
     MetadataAllocation<Runtime> Allocation) {
     if (Allocation.Tag == GenericMetadataCacheTag) {
-        auto AllocationBytes =
-          getReader().readBytes(RemoteAddress(Allocation.Ptr),
-                                              Allocation.Size);
-        if (!AllocationBytes)
-          return 0;
-        auto Entry =
+      auto AllocationBytes = getReader().readBytes(
+          RemoteAddress(Allocation.Ptr, RemoteAddress::DefaultAddressSpace),
+          Allocation.Size);
+      if (!AllocationBytes)
+        return 0;
+      auto Entry =
           reinterpret_cast<const GenericMetadataCacheEntry<StoredPointer> *>(
-            AllocationBytes.get());
-        return Entry->Value;
+              AllocationBytes.get());
+      return Entry->Value;
     }
     return 0;
   }
@@ -1462,7 +1768,8 @@ class ReflectionContext
     case ForeignMetadataCacheTag:
     case GenericWitnessTableCacheTag: {
       auto NodeBytes = getReader().readBytes(
-          RemoteAddress(Allocation.Ptr), sizeof(MetadataCacheNode<Runtime>));
+          RemoteAddress(Allocation.Ptr, RemoteAddress::DefaultAddressSpace),
+          sizeof(MetadataCacheNode<Runtime>));
       if (!NodeBytes)
         return std::nullopt;
       auto Node =
@@ -1505,14 +1812,14 @@ class ReflectionContext
       return "failed to read value of " + AllocationPoolPointerName;
 
     struct PoolRange {
-      StoredPointer Begin;
+      RemoteAddress Begin;
       StoredSize Remaining;
     };
     struct PoolTrailer {
-      StoredPointer PrevTrailer;
+      RemoteAddress PrevTrailer;
       StoredSize PoolSize;
     };
-    struct alignas(StoredPointer) AllocationHeader {
+    struct alignas(RemoteAddress) AllocationHeader {
       uint16_t Size;
       uint16_t Tag;
     };
@@ -1532,14 +1839,13 @@ class ReflectionContext
 
     auto TrailerPtr = Pool->Begin + Pool->Remaining;
     while (TrailerPtr && LoopCount++ < LoopLimit) {
-      auto TrailerBytes = getReader()
-        .readBytes(RemoteAddress(TrailerPtr), sizeof(PoolTrailer));
+      auto TrailerBytes =
+          getReader().readBytes(TrailerPtr, sizeof(PoolTrailer));
       if (!TrailerBytes)
         break;
       auto Trailer = reinterpret_cast<const PoolTrailer *>(TrailerBytes.get());
       auto PoolStart = TrailerPtr - Trailer->PoolSize;
-      auto PoolBytes = getReader()
-        .readBytes(RemoteAddress(PoolStart), Trailer->PoolSize);
+      auto PoolBytes = getReader().readBytes(PoolStart, Trailer->PoolSize);
       if (!PoolBytes)
         break;
       auto PoolPtr = (const char *)PoolBytes.get();
@@ -1553,7 +1859,10 @@ class ReflectionContext
         auto RemoteAddr = PoolStart + Offset + sizeof(AllocationHeader);
         MetadataAllocation<Runtime> Allocation;
         Allocation.Tag = Header->Tag;
-        Allocation.Ptr = RemoteAddr;
+
+        if (RemoteAddr.getAddressSpace() != RemoteAddress::DefaultAddressSpace)
+          return "storing remote address from non-default address space.";
+        Allocation.Ptr = RemoteAddr.getRawAddress();
         Allocation.Size = Header->Size;
         Call(Allocation);
 
@@ -1589,15 +1898,15 @@ class ReflectionContext
     auto BacktraceListNext = BacktraceListNextPtr->getResolvedAddress();
     while (BacktraceListNext && LoopCount++ < LoopLimit) {
       auto HeaderBytes = getReader().readBytes(
-          RemoteAddress(BacktraceListNext),
+          BacktraceListNext,
           sizeof(MetadataAllocationBacktraceHeader<Runtime>));
       if (!HeaderBytes) {
         // FIXME: std::stringstream would be better, but LLVM's standard library
         // introduces a vtable and we don't want that.
         char result[128];
         std::snprintf(result, sizeof(result),
-            "unable to read Next pointer %#" PRIx64,
-            BacktraceListNext.getAddressData());
+                      "unable to read Next pointer %#" PRIx64,
+                      BacktraceListNext.getRawAddress());
         return std::string(result);
       }
       auto HeaderPtr =
@@ -1606,15 +1915,15 @@ class ReflectionContext
       auto BacktraceAddrPtr =
           BacktraceListNext +
           sizeof(MetadataAllocationBacktraceHeader<Runtime>);
-      auto BacktraceBytes =
-          getReader().readBytes(RemoteAddress(BacktraceAddrPtr),
-                                HeaderPtr->Count * sizeof(StoredPointer));
+      auto BacktraceBytes = getReader().readBytes(
+          BacktraceAddrPtr, HeaderPtr->Count * sizeof(StoredPointer));
       auto BacktracePtr =
           reinterpret_cast<const StoredPointer *>(BacktraceBytes.get());
 
       Call(HeaderPtr->Allocation, HeaderPtr->Count, BacktracePtr);
 
-      BacktraceListNext = RemoteAddress(HeaderPtr->Next);
+      BacktraceListNext =
+          RemoteAddress(HeaderPtr->Next, RemoteAddress::DefaultAddressSpace);
     }
     return std::nullopt;
   }
@@ -1623,7 +1932,8 @@ class ReflectionContext
   asyncTaskSlabAllocations(StoredPointer SlabPtr) {
     using StackAllocator = StackAllocator<Runtime>;
     auto SlabBytes = getReader().readBytes(
-        RemoteAddress(SlabPtr), sizeof(typename StackAllocator::Slab));
+        RemoteAddress(SlabPtr, RemoteAddress::DefaultAddressSpace),
+        sizeof(typename StackAllocator::Slab));
     auto Slab = reinterpret_cast<const typename StackAllocator::Slab *>(
         SlabBytes.get());
     if (!Slab)
@@ -1648,14 +1958,14 @@ class ReflectionContext
     NextPtrChunk.Kind = AsyncTaskAllocationChunk::ChunkKind::RawPointer;
 
     // Total slab size is the slab's capacity plus the header.
-    StoredPointer SlabSize = Slab->Capacity + HeaderSize;
+    auto SlabSize = Slab->Capacity + HeaderSize;
 
     return {std::nullopt,
             {Slab->Next, SlabSize, {NextPtrChunk, AllocatedSpaceChunk}}};
   }
 
   std::pair<std::optional<std::string>, AsyncTaskInfo>
-  asyncTaskInfo(StoredPointer AsyncTaskPtr, unsigned ChildTaskLimit,
+  asyncTaskInfo(RemoteAddress AsyncTaskPtr, unsigned ChildTaskLimit,
                 unsigned AsyncBacktraceLimit) {
     loadTargetPointers();
 
@@ -1670,7 +1980,7 @@ class ReflectionContext
   }
 
   std::pair<std::optional<std::string>, ActorInfo>
-  actorInfo(StoredPointer ActorPtr) {
+  actorInfo(RemoteAddress ActorPtr) {
     if (supportsPriorityEscalation)
       return actorInfo<
           DefaultActorImpl<Runtime, ActiveActorStatusWithEscalation<Runtime>>>(
@@ -1680,10 +1990,10 @@ class ReflectionContext
           Runtime, ActiveActorStatusWithoutEscalation<Runtime>>>(ActorPtr);
   }
 
-  StoredPointer nextJob(StoredPointer JobPtr) {
+  StoredPointer nextJob(RemoteAddress JobPtr) {
     using Job = Job<Runtime>;
 
-    auto JobBytes = getReader().readBytes(RemoteAddress(JobPtr), sizeof(Job));
+    auto JobBytes = getReader().readBytes(JobPtr, sizeof(Job));
     auto *JobObj = reinterpret_cast<const Job *>(JobBytes.get());
     if (!JobObj)
       return 0;
@@ -1758,7 +2068,7 @@ class ReflectionContext
 
   template <typename AsyncTaskType>
   std::pair<std::optional<std::string>, AsyncTaskInfo>
-  asyncTaskInfo(StoredPointer AsyncTaskPtr, unsigned ChildTaskLimit,
+  asyncTaskInfo(RemoteAddress AsyncTaskPtr, unsigned ChildTaskLimit,
                 unsigned AsyncBacktraceLimit) {
     auto AsyncTaskObj = readObj<AsyncTaskType>(AsyncTaskPtr);
     if (!AsyncTaskObj)
@@ -1781,6 +2091,8 @@ class ReflectionContext
     Info.IsEscalated = TaskStatusFlags & ActiveTaskStatusFlags::IsEscalated;
     Info.IsEnqueued = TaskStatusFlags & ActiveTaskStatusFlags::IsEnqueued;
     Info.IsComplete = TaskStatusFlags & ActiveTaskStatusFlags::IsComplete;
+    Info.IsSuspended =
+        TaskStatusFlags & ActiveTaskStatusFlags::HasTaskDependency;
 
     setIsRunning(Info, AsyncTaskObj.get());
     std::tie(Info.HasThreadPort, Info.ThreadPort) =
@@ -1793,7 +2105,8 @@ class ReflectionContext
 
     // Find all child tasks.
     unsigned ChildTaskLoopCount = 0;
-    auto RecordPtr = AsyncTaskObj->PrivateStorage.Status.Record;
+    auto RecordPtr = RemoteAddress(AsyncTaskObj->PrivateStorage.Status.Record,
+                                   RemoteAddress::DefaultAddressSpace);
     while (RecordPtr && ChildTaskLoopCount++ < ChildTaskLimit) {
       auto RecordObj = readObj<TaskStatusRecord<Runtime>>(RecordPtr);
       if (!RecordObj)
@@ -1816,22 +2129,44 @@ class ReflectionContext
           ChildTask = RecordObj->FirstChild;
       }
 
-      while (ChildTask) {
+      while (ChildTask && ChildTaskLoopCount++ < ChildTaskLimit) {
+        RemoteAddress ChildTaskAddress =
+            RemoteAddress(ChildTask, RemoteAddress::DefaultAddressSpace);
+        // Read the child task.
+        auto ChildTaskObj = readObj<AsyncTaskType>(ChildTaskAddress);
+        if (!ChildTaskObj)
+          return {std::string("found unreadable child task pointer"), Info};
+
         Info.ChildTasks.push_back(ChildTask);
 
-        StoredPointer ChildFragmentAddr = ChildTask + sizeof(*AsyncTaskObj);
-        auto ChildFragmentObj =
-            readObj<ChildFragment<Runtime>>(ChildFragmentAddr);
-        if (ChildFragmentObj)
-          ChildTask = ChildFragmentObj->NextChild;
-        else
+        swift::JobFlags ChildJobFlags(AsyncTaskObj->Flags);
+        if (ChildJobFlags.task_isChildTask()) {
+          if (asyncTaskSize == 0)
+            return {std::string("target async task size unknown, unable to "
+                                "iterate child tasks"),
+                    Info};
+
+          RemoteAddress ChildFragmentAddr = ChildTaskAddress + asyncTaskSize;
+          auto ChildFragmentObj =
+              readObj<ChildFragment<Runtime>>(ChildFragmentAddr);
+          if (ChildFragmentObj)
+            ChildTask = ChildFragmentObj->NextChild;
+          else
+            ChildTask = 0;
+        } else {
+          // No child fragment, so we're done iterating.
           ChildTask = 0;
+        }
       }
 
-      RecordPtr = RecordObj->Parent;
+      RecordPtr =
+          RemoteAddress(RecordObj->Parent, RemoteAddress::DefaultAddressSpace);
     }
 
-    const auto TaskResumeContext = AsyncTaskObj->ResumeContextAndReserved[0];
+    const auto TaskResumeContext = stripSignedPointer(
+      RemoteAddress(AsyncTaskObj->ResumeContextAndReserved[0],
+                    RemoteAddress::DefaultAddressSpace)
+    ).getRawAddress();
     Info.ResumeAsyncContext = TaskResumeContext;
 
     // Walk the async backtrace.
@@ -1839,12 +2174,14 @@ class ReflectionContext
       auto ResumeContext = TaskResumeContext;
       unsigned AsyncBacktraceLoopCount = 0;
       while (ResumeContext && AsyncBacktraceLoopCount++ < AsyncBacktraceLimit) {
-        auto ResumeContextObj = readObj<AsyncContext<Runtime>>(ResumeContext);
+        auto ResumeContextObj = readObj<AsyncContext<Runtime>>(
+            RemoteAddress(ResumeContext, RemoteAddress::DefaultAddressSpace));
         if (!ResumeContextObj)
           break;
         Info.AsyncBacktraceFrames.push_back(
-            stripSignedPointer(ResumeContextObj->ResumeParent));
-        ResumeContext = stripSignedPointer(ResumeContextObj->Parent);
+            stripSignedPointer(ResumeContextObj->ResumeParent).getRawAddress());
+        ResumeContext =
+            stripSignedPointer(ResumeContextObj->Parent).getRawAddress();
       }
     }
 
@@ -1853,7 +2190,7 @@ class ReflectionContext
 
   template <typename ActorType>
   std::pair<std::optional<std::string>, ActorInfo>
-  actorInfo(StoredPointer ActorPtr) {
+  actorInfo(RemoteAddress ActorPtr) {
     auto ActorObj = readObj<ActorType>(ActorPtr);
     if (!ActorObj)
       return {std::string("failure reading actor"), {}};
@@ -1872,7 +2209,7 @@ class ReflectionContext
     // Don't read FirstJob when idle.
     if (Info.State != concurrency::ActorFlagConstants::Idle) {
       // This is a JobRef which stores flags in the low bits.
-      Info.FirstJob = ActorObj->Status.FirstJob & ~StoredPointer(0x3);
+      Info.FirstJob = ActorObj->Status.FirstJob & ~0x3;
     }
 
     std::tie(Info.HasThreadPort, Info.ThreadPort) =
@@ -1885,38 +2222,46 @@ class ReflectionContext
   // like AsyncTask::getResumeFunctionForLogging does.
   template <typename AsyncTaskType>
   StoredPointer getRunJob(const AsyncTaskType *AsyncTaskObj) {
-    auto Fptr = stripSignedPointer(AsyncTaskObj->RunJob);
+    auto Fptr = stripSignedPointer(AsyncTaskObj->RunJob).getRawAddress();
 
     loadTargetPointers();
     auto ResumeContextPtr = AsyncTaskObj->ResumeContextAndReserved[0];
     if (target_non_future_adapter && Fptr == target_non_future_adapter) {
       using Prefix = AsyncContextPrefix<Runtime>;
       auto PrefixAddr = ResumeContextPtr - sizeof(Prefix);
-      auto PrefixBytes =
-          getReader().readBytes(RemoteAddress(PrefixAddr), sizeof(Prefix));
+      auto PrefixBytes = getReader().readBytes(
+          RemoteAddress(PrefixAddr, RemoteAddress::DefaultAddressSpace),
+          sizeof(Prefix));
       if (PrefixBytes) {
         auto PrefixPtr = reinterpret_cast<const Prefix *>(PrefixBytes.get());
-        return stripSignedPointer(PrefixPtr->AsyncEntryPoint);
+        return stripSignedPointer(PrefixPtr->AsyncEntryPoint).getRawAddress();
       }
     } else if (target_future_adapter && Fptr == target_future_adapter) {
       using Prefix = FutureAsyncContextPrefix<Runtime>;
       auto PrefixAddr = ResumeContextPtr - sizeof(Prefix);
-      auto PrefixBytes =
-          getReader().readBytes(RemoteAddress(PrefixAddr), sizeof(Prefix));
+      auto PrefixBytes = getReader().readBytes(
+          RemoteAddress(PrefixAddr, RemoteAddress::DefaultAddressSpace),
+          sizeof(Prefix));
       if (PrefixBytes) {
         auto PrefixPtr = reinterpret_cast<const Prefix *>(PrefixBytes.get());
-        return stripSignedPointer(PrefixPtr->AsyncEntryPoint);
+        return stripSignedPointer(PrefixPtr->AsyncEntryPoint).getRawAddress();
       }
     } else if ((target_task_wait_throwing_resume_adapter &&
                 Fptr == target_task_wait_throwing_resume_adapter) ||
                (target_task_future_wait_resume_adapter &&
                 Fptr == target_task_future_wait_resume_adapter)) {
-      auto ContextBytes = getReader().readBytes(RemoteAddress(ResumeContextPtr),
-                                                sizeof(AsyncContext<Runtime>));
-      if (ContextBytes) {
-        auto ContextPtr =
-            reinterpret_cast<const AsyncContext<Runtime> *>(ContextBytes.get());
-        return stripSignedPointer(ContextPtr->ResumeParent);
+      // It's only safe to look through these adapters when there's a dependency
+      // record. If there isn't a dependency record, then the task was resumed
+      // and the pointers are potentially stale.
+      if (AsyncTaskObj->PrivateStorage.DependencyRecord) {
+        auto ContextBytes = getReader().readBytes(
+            RemoteAddress(ResumeContextPtr, RemoteAddress::DefaultAddressSpace),
+            sizeof(AsyncContext<Runtime>));
+        if (ContextBytes) {
+          auto ContextPtr = reinterpret_cast<const AsyncContext<Runtime> *>(
+              ContextBytes.get());
+          return stripSignedPointer(ContextPtr->ResumeParent).getRawAddress();
+        }
       }
     }
 
@@ -1927,34 +2272,42 @@ class ReflectionContext
     if (setupTargetPointers)
       return;
 
-    auto getFunc = [&](const std::string &name) -> StoredPointer {
+    auto getPointer = [&](const std::string &name) -> StoredPointer {
       auto Symbol = getReader().getSymbolAddress(name);
       if (!Symbol)
         return 0;
       auto Pointer = getReader().readPointer(Symbol, sizeof(StoredPointer));
       if (!Pointer)
         return 0;
-      return Pointer->getResolvedAddress().getAddressData();
+      return Pointer->getResolvedAddress().getRawAddress();
     };
+    target_asyncTaskMetadata =
+        getPointer("_swift_concurrency_debug_asyncTaskMetadata");
     target_non_future_adapter =
-        getFunc("_swift_concurrency_debug_non_future_adapter");
-    target_future_adapter = getFunc("_swift_concurrency_debug_future_adapter");
-    target_task_wait_throwing_resume_adapter =
-        getFunc("_swift_concurrency_debug_task_wait_throwing_resume_adapter");
+        getPointer("_swift_concurrency_debug_non_future_adapter");
+    target_future_adapter =
+        getPointer("_swift_concurrency_debug_future_adapter");
+    target_task_wait_throwing_resume_adapter = getPointer(
+        "_swift_concurrency_debug_task_wait_throwing_resume_adapter");
     target_task_future_wait_resume_adapter =
-        getFunc("_swift_concurrency_debug_task_future_wait_resume_adapter");
+        getPointer("_swift_concurrency_debug_task_future_wait_resume_adapter");
     auto supportsPriorityEscalationAddr = getReader().getSymbolAddress(
         "_swift_concurrency_debug_supportsPriorityEscalation");
     if (supportsPriorityEscalationAddr) {
       getReader().readInteger(supportsPriorityEscalationAddr,
                               &supportsPriorityEscalation);
     }
+    auto asyncTaskSizeAddr =
+        getReader().getSymbolAddress("_swift_concurrency_debug_asyncTaskSize");
+    if (asyncTaskSizeAddr) {
+      getReader().readInteger(asyncTaskSizeAddr, &asyncTaskSize);
+    }
 
     setupTargetPointers = true;
   }
 
   const TypeInfo *
-  getClosureContextInfo(StoredPointer Context, const ClosureContextInfo &Info,
+  getClosureContextInfo(RemoteAddress Context, const ClosureContextInfo &Info,
                         remote::TypeInfoProvider *ExternalTypeInfo) {
     RecordTypeInfoBuilder Builder(getBuilder().getTypeConverter(),
                                   RecordKind::ClosureContext);
@@ -2103,8 +2456,8 @@ class ReflectionContext
   /// above.
   ///
   /// \param Builder Used to obtain offsets of elements known so far.
-  std::optional<StoredPointer>
-  readMetadataSource(StoredPointer Context, const MetadataSource *MS,
+  std::optional<RemoteAddress>
+  readMetadataSource(RemoteAddress Context, const MetadataSource *MS,
                      const RecordTypeInfoBuilder &Builder) {
     switch (MS->getKind()) {
     case MetadataSourceKind::ClosureBinding: {
@@ -2120,9 +2473,9 @@ class ReflectionContext
       unsigned Offset = getSizeOfHeapObject() +
                         sizeof(StoredPointer) * Index;
 
-      StoredPointer MetadataAddress;
-      if (!getReader().readInteger(RemoteAddress(Context + Offset),
-                                   &MetadataAddress))
+      RemoteAddress MetadataAddress;
+      if (!getReader().template readRemoteAddress<StoredPointer>(
+              Context + Offset, MetadataAddress))
         break;
 
       return MetadataAddress;
@@ -2134,9 +2487,9 @@ class ReflectionContext
       // of this capture in the context.
       unsigned CaptureOffset = Builder.getFieldOffset(Index);
 
-      StoredPointer CaptureAddress;
-      if (!getReader().readInteger(RemoteAddress(Context + CaptureOffset),
-                                   &CaptureAddress))
+      RemoteAddress CaptureAddress;
+      if (!getReader().template readRemoteAddress<StoredPointer>(
+              Context + CaptureOffset, CaptureAddress))
         break;
 
       // Read the requested capture's isa pointer.
@@ -2149,9 +2502,9 @@ class ReflectionContext
       // of this capture in the context.
       unsigned CaptureOffset = Builder.getFieldOffset(Index);
 
-      StoredPointer CaptureAddress;
-      if (!getReader().readInteger(RemoteAddress(Context + CaptureOffset),
-                                   &CaptureAddress))
+      RemoteAddress CaptureAddress;
+      if (!getReader().template readRemoteAddress<StoredPointer>(
+              Context + CaptureOffset, CaptureAddress))
         break;
 
       return CaptureAddress;
@@ -2178,8 +2531,8 @@ class ReflectionContext
   }
 
   template <typename T>
-  MemoryReader::ReadObjResult<T> readObj(StoredPointer Ptr) {
-    return getReader().template readObj<T>(RemoteAddress(Ptr));
+  MemoryReader::ReadObjResult<T> readObj(RemoteAddress Ptr) {
+    return getReader().template readObj<T>(Ptr);
   }
 };
 
diff --git a/include/swift/RemoteInspection/RuntimeHeaders/llvm/BinaryFormat/Wasm.h b/include/swift/RemoteInspection/RuntimeHeaders/llvm/BinaryFormat/Wasm.h
new file mode 100644
index 0000000000000..7c6e6494500bf
--- /dev/null
+++ b/include/swift/RemoteInspection/RuntimeHeaders/llvm/BinaryFormat/Wasm.h
@@ -0,0 +1,581 @@
+//===- Wasm.h - Wasm object file format -------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines manifest constants for the wasm object file format.
+// See: https://github.com/WebAssembly/design/blob/main/BinaryEncoding.md
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_BINARYFORMAT_WASM_H
+#define LLVM_BINARYFORMAT_WASM_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Compiler.h"
+#include <optional>
+
+namespace llvm {
+namespace wasm {
+
+// Object file magic string.
+const char WasmMagic[] = {'\0', 'a', 's', 'm'};
+// Wasm binary format version
+const uint32_t WasmVersion = 0x1;
+// Wasm linking metadata version
+const uint32_t WasmMetadataVersion = 0x2;
+// Wasm uses a 64k page size by default (but the custom-page-sizes proposal
+// allows changing it)
+const uint32_t WasmDefaultPageSize = 65536;
+
+enum : unsigned {
+  WASM_SEC_CUSTOM = 0,     // Custom / User-defined section
+  WASM_SEC_TYPE = 1,       // Function signature declarations
+  WASM_SEC_IMPORT = 2,     // Import declarations
+  WASM_SEC_FUNCTION = 3,   // Function declarations
+  WASM_SEC_TABLE = 4,      // Indirect function table and other tables
+  WASM_SEC_MEMORY = 5,     // Memory attributes
+  WASM_SEC_GLOBAL = 6,     // Global declarations
+  WASM_SEC_EXPORT = 7,     // Exports
+  WASM_SEC_START = 8,      // Start function declaration
+  WASM_SEC_ELEM = 9,       // Elements section
+  WASM_SEC_CODE = 10,      // Function bodies (code)
+  WASM_SEC_DATA = 11,      // Data segments
+  WASM_SEC_DATACOUNT = 12, // Data segment count
+  WASM_SEC_TAG = 13,       // Tag declarations
+  WASM_SEC_LAST_KNOWN = WASM_SEC_TAG,
+};
+
+// Type immediate encodings used in various contexts.
+enum : unsigned {
+  WASM_TYPE_I32 = 0x7F,
+  WASM_TYPE_I64 = 0x7E,
+  WASM_TYPE_F32 = 0x7D,
+  WASM_TYPE_F64 = 0x7C,
+  WASM_TYPE_V128 = 0x7B,
+  WASM_TYPE_NULLFUNCREF = 0x73,
+  WASM_TYPE_NULLEXTERNREF = 0x72,
+  WASM_TYPE_NULLEXNREF = 0x74,
+  WASM_TYPE_NULLREF = 0x71,
+  WASM_TYPE_FUNCREF = 0x70,
+  WASM_TYPE_EXTERNREF = 0x6F,
+  WASM_TYPE_EXNREF = 0x69,
+  WASM_TYPE_ANYREF = 0x6E,
+  WASM_TYPE_EQREF = 0x6D,
+  WASM_TYPE_I31REF = 0x6C,
+  WASM_TYPE_STRUCTREF = 0x6B,
+  WASM_TYPE_ARRAYREF = 0x6A,
+  WASM_TYPE_NONNULLABLE = 0x64,
+  WASM_TYPE_NULLABLE = 0x63,
+  WASM_TYPE_FUNC = 0x60,
+  WASM_TYPE_ARRAY = 0x5E,
+  WASM_TYPE_STRUCT = 0x5F,
+  WASM_TYPE_SUB = 0x50,
+  WASM_TYPE_SUB_FINAL = 0x4F,
+  WASM_TYPE_REC = 0x4E,
+  WASM_TYPE_NORESULT = 0x40, // for blocks with no result values
+};
+
+// Kinds of externals (for imports and exports).
+enum : unsigned {
+  WASM_EXTERNAL_FUNCTION = 0x0,
+  WASM_EXTERNAL_TABLE = 0x1,
+  WASM_EXTERNAL_MEMORY = 0x2,
+  WASM_EXTERNAL_GLOBAL = 0x3,
+  WASM_EXTERNAL_TAG = 0x4,
+};
+
+// Opcodes used in initializer expressions.
+enum : unsigned {
+  WASM_OPCODE_END = 0x0b,
+  WASM_OPCODE_CALL = 0x10,
+  WASM_OPCODE_LOCAL_GET = 0x20,
+  WASM_OPCODE_LOCAL_SET = 0x21,
+  WASM_OPCODE_LOCAL_TEE = 0x22,
+  WASM_OPCODE_GLOBAL_GET = 0x23,
+  WASM_OPCODE_GLOBAL_SET = 0x24,
+  WASM_OPCODE_I32_STORE = 0x36,
+  WASM_OPCODE_I64_STORE = 0x37,
+  WASM_OPCODE_I32_CONST = 0x41,
+  WASM_OPCODE_I64_CONST = 0x42,
+  WASM_OPCODE_F32_CONST = 0x43,
+  WASM_OPCODE_F64_CONST = 0x44,
+  WASM_OPCODE_I32_ADD = 0x6a,
+  WASM_OPCODE_I32_SUB = 0x6b,
+  WASM_OPCODE_I32_MUL = 0x6c,
+  WASM_OPCODE_I64_ADD = 0x7c,
+  WASM_OPCODE_I64_SUB = 0x7d,
+  WASM_OPCODE_I64_MUL = 0x7e,
+  WASM_OPCODE_REF_NULL = 0xd0,
+  WASM_OPCODE_REF_FUNC = 0xd2,
+  WASM_OPCODE_GC_PREFIX = 0xfb,
+};
+
+// Opcodes in the GC-prefixed space (0xfb)
+enum : unsigned {
+  WASM_OPCODE_STRUCT_NEW = 0x00,
+  WASM_OPCODE_STRUCT_NEW_DEFAULT = 0x01,
+  WASM_OPCODE_ARRAY_NEW = 0x06,
+  WASM_OPCODE_ARRAY_NEW_DEFAULT = 0x07,
+  WASM_OPCODE_ARRAY_NEW_FIXED = 0x08,
+  WASM_OPCODE_REF_I31 = 0x1c,
+  // any.convert_extern and extern.convert_any don't seem to be supported by
+  // Binaryen.
+};
+
+// Opcodes used in synthetic functions.
+enum : unsigned {
+  WASM_OPCODE_BLOCK = 0x02,
+  WASM_OPCODE_BR = 0x0c,
+  WASM_OPCODE_BR_TABLE = 0x0e,
+  WASM_OPCODE_RETURN = 0x0f,
+  WASM_OPCODE_DROP = 0x1a,
+  WASM_OPCODE_MISC_PREFIX = 0xfc,
+  WASM_OPCODE_MEMORY_INIT = 0x08,
+  WASM_OPCODE_MEMORY_FILL = 0x0b,
+  WASM_OPCODE_DATA_DROP = 0x09,
+  WASM_OPCODE_ATOMICS_PREFIX = 0xfe,
+  WASM_OPCODE_ATOMIC_NOTIFY = 0x00,
+  WASM_OPCODE_I32_ATOMIC_WAIT = 0x01,
+  WASM_OPCODE_I32_ATOMIC_STORE = 0x17,
+  WASM_OPCODE_I32_RMW_CMPXCHG = 0x48,
+};
+
+// Sub-opcodes for catch clauses in a try_table instruction
+enum : unsigned {
+  WASM_OPCODE_CATCH = 0x00,
+  WASM_OPCODE_CATCH_REF = 0x01,
+  WASM_OPCODE_CATCH_ALL = 0x02,
+  WASM_OPCODE_CATCH_ALL_REF = 0x03,
+};
+
+enum : unsigned {
+  WASM_LIMITS_FLAG_NONE = 0x0,
+  WASM_LIMITS_FLAG_HAS_MAX = 0x1,
+  WASM_LIMITS_FLAG_IS_SHARED = 0x2,
+  WASM_LIMITS_FLAG_IS_64 = 0x4,
+  WASM_LIMITS_FLAG_HAS_PAGE_SIZE = 0x8,
+};
+
+enum : unsigned {
+  WASM_DATA_SEGMENT_IS_PASSIVE = 0x01,
+  WASM_DATA_SEGMENT_HAS_MEMINDEX = 0x02,
+};
+
+enum : unsigned {
+  WASM_ELEM_SEGMENT_IS_PASSIVE = 0x01,
+  WASM_ELEM_SEGMENT_IS_DECLARATIVE = 0x02,   // if passive == 1
+  WASM_ELEM_SEGMENT_HAS_TABLE_NUMBER = 0x02, // if passive == 0
+  WASM_ELEM_SEGMENT_HAS_INIT_EXPRS = 0x04,
+};
+const unsigned WASM_ELEM_SEGMENT_MASK_HAS_ELEM_DESC = 0x3;
+
+// Feature policy prefixes used in the custom "target_features" section
+enum : uint8_t {
+  WASM_FEATURE_PREFIX_USED = '+',
+  WASM_FEATURE_PREFIX_DISALLOWED = '-',
+};
+
+// Kind codes used in the custom "name" section
+enum : unsigned {
+  WASM_NAMES_MODULE = 0,
+  WASM_NAMES_FUNCTION = 1,
+  WASM_NAMES_LOCAL = 2,
+  WASM_NAMES_GLOBAL = 7,
+  WASM_NAMES_DATA_SEGMENT = 9,
+};
+
+// Kind codes used in the custom "linking" section
+enum : unsigned {
+  WASM_SEGMENT_INFO = 0x5,
+  WASM_INIT_FUNCS = 0x6,
+  WASM_COMDAT_INFO = 0x7,
+  WASM_SYMBOL_TABLE = 0x8,
+};
+
+// Kind codes used in the custom "dylink" section
+enum : unsigned {
+  WASM_DYLINK_MEM_INFO = 0x1,
+  WASM_DYLINK_NEEDED = 0x2,
+  WASM_DYLINK_EXPORT_INFO = 0x3,
+  WASM_DYLINK_IMPORT_INFO = 0x4,
+  WASM_DYLINK_RUNTIME_PATH = 0x5,
+};
+
+// Kind codes used in the custom "linking" section in the WASM_COMDAT_INFO
+enum : unsigned {
+  WASM_COMDAT_DATA = 0x0,
+  WASM_COMDAT_FUNCTION = 0x1,
+  // GLOBAL, TAG, and TABLE are in here but LLVM doesn't use them yet.
+  WASM_COMDAT_SECTION = 0x5,
+};
+
+// Kind codes used in the custom "linking" section in the WASM_SYMBOL_TABLE
+enum WasmSymbolType : unsigned {
+  WASM_SYMBOL_TYPE_FUNCTION = 0x0,
+  WASM_SYMBOL_TYPE_DATA = 0x1,
+  WASM_SYMBOL_TYPE_GLOBAL = 0x2,
+  WASM_SYMBOL_TYPE_SECTION = 0x3,
+  WASM_SYMBOL_TYPE_TAG = 0x4,
+  WASM_SYMBOL_TYPE_TABLE = 0x5,
+};
+
+enum WasmSegmentFlag : unsigned {
+  WASM_SEG_FLAG_STRINGS = 0x1,
+  WASM_SEG_FLAG_TLS = 0x2,
+  WASM_SEG_FLAG_RETAIN = 0x4,
+};
+
+// Kinds of tag attributes.
+enum WasmTagAttribute : uint8_t {
+  WASM_TAG_ATTRIBUTE_EXCEPTION = 0x0,
+};
+
+const unsigned WASM_SYMBOL_BINDING_MASK = 0x3;
+const unsigned WASM_SYMBOL_VISIBILITY_MASK = 0xc;
+
+const unsigned WASM_SYMBOL_BINDING_GLOBAL = 0x0;
+const unsigned WASM_SYMBOL_BINDING_WEAK = 0x1;
+const unsigned WASM_SYMBOL_BINDING_LOCAL = 0x2;
+const unsigned WASM_SYMBOL_VISIBILITY_DEFAULT = 0x0;
+const unsigned WASM_SYMBOL_VISIBILITY_HIDDEN = 0x4;
+const unsigned WASM_SYMBOL_UNDEFINED = 0x10;
+const unsigned WASM_SYMBOL_EXPORTED = 0x20;
+const unsigned WASM_SYMBOL_EXPLICIT_NAME = 0x40;
+const unsigned WASM_SYMBOL_NO_STRIP = 0x80;
+const unsigned WASM_SYMBOL_TLS = 0x100;
+const unsigned WASM_SYMBOL_ABSOLUTE = 0x200;
+
+#define WASM_RELOC(name, value) name = value,
+
+enum WasmRelocType : unsigned {
+#include "WasmRelocs.def"
+};
+
+#undef WASM_RELOC
+
+struct WasmObjectHeader {
+  StringRef Magic;
+  uint32_t Version;
+};
+
+// Subset of types that a value can have
+enum class ValType {
+  I32 = WASM_TYPE_I32,
+  I64 = WASM_TYPE_I64,
+  F32 = WASM_TYPE_F32,
+  F64 = WASM_TYPE_F64,
+  V128 = WASM_TYPE_V128,
+  FUNCREF = WASM_TYPE_FUNCREF,
+  EXTERNREF = WASM_TYPE_EXTERNREF,
+  EXNREF = WASM_TYPE_EXNREF,
+  // Unmodeled value types include ref types with heap types other than
+  // func, extern or exn, and type-specialized funcrefs
+  OTHERREF = 0xff,
+};
+
+struct WasmDylinkImportInfo {
+  StringRef Module;
+  StringRef Field;
+  uint32_t Flags;
+};
+
+struct WasmDylinkExportInfo {
+  StringRef Name;
+  uint32_t Flags;
+};
+
+struct WasmDylinkInfo {
+  uint32_t MemorySize;           // Memory size in bytes
+  uint32_t MemoryAlignment;      // P2 alignment of memory
+  uint32_t TableSize;            // Table size in elements
+  uint32_t TableAlignment;       // P2 alignment of table
+  std::vector<StringRef> Needed; // Shared library dependencies
+  std::vector<WasmDylinkImportInfo> ImportInfo;
+  std::vector<WasmDylinkExportInfo> ExportInfo;
+  std::vector<StringRef> RuntimePath;
+};
+
+struct WasmProducerInfo {
+  std::vector<std::pair<std::string, std::string>> Languages;
+  std::vector<std::pair<std::string, std::string>> Tools;
+  std::vector<std::pair<std::string, std::string>> SDKs;
+};
+
+struct WasmFeatureEntry {
+  uint8_t Prefix;
+  std::string Name;
+};
+
+struct WasmExport {
+  StringRef Name;
+  uint8_t Kind;
+  uint32_t Index;
+};
+
+struct WasmLimits {
+  uint8_t Flags;
+  uint64_t Minimum;
+  uint64_t Maximum;
+  uint32_t PageSize;
+};
+
+struct WasmTableType {
+  ValType ElemType;
+  WasmLimits Limits;
+};
+
+struct WasmTable {
+  uint32_t Index;
+  WasmTableType Type;
+  StringRef SymbolName; // from the "linking" section
+};
+
+struct WasmInitExprMVP {
+  uint8_t Opcode;
+  union {
+    int32_t Int32;
+    int64_t Int64;
+    uint32_t Float32;
+    uint64_t Float64;
+    uint32_t Global;
+  } Value;
+};
+
+// Extended-const init exprs and exprs with GC types are not explicitly
+// modeled, but the raw body of the expr is attached.
+struct WasmInitExpr {
+  uint8_t Extended; // Set to non-zero if extended const is used (i.e. more than
+                    // one instruction)
+  WasmInitExprMVP Inst;
+  ArrayRef<uint8_t> Body;
+};
+
+struct WasmGlobalType {
+  uint8_t Type; // TODO: make this a ValType?
+  bool Mutable;
+};
+
+struct WasmGlobal {
+  uint32_t Index;
+  WasmGlobalType Type;
+  WasmInitExpr InitExpr;
+  StringRef SymbolName; // from the "linking" section
+  uint32_t Offset; // Offset of the definition in the binary's Global section
+  uint32_t Size;   // Size of the definition in the binary's Global section
+};
+
+struct WasmTag {
+  uint32_t Index;
+  uint32_t SigIndex;
+  StringRef SymbolName; // from the "linking" section
+};
+
+struct WasmImport {
+  StringRef Module;
+  StringRef Field;
+  uint8_t Kind;
+  union {
+    uint32_t SigIndex;
+    WasmGlobalType Global;
+    WasmTableType Table;
+    WasmLimits Memory;
+  };
+};
+
+struct WasmLocalDecl {
+  uint8_t Type;
+  uint32_t Count;
+};
+
+struct WasmFunction {
+  uint32_t Index;
+  uint32_t SigIndex;
+  std::vector<WasmLocalDecl> Locals;
+  ArrayRef<uint8_t> Body;
+  uint32_t CodeSectionOffset;
+  uint32_t Size;
+  uint32_t CodeOffset;                 // start of Locals and Body
+  std::optional<StringRef> ExportName; // from the "export" section
+  StringRef SymbolName;                // from the "linking" section
+  StringRef DebugName;                 // from the "name" section
+  uint32_t Comdat;                     // from the "comdat info" section
+};
+
+struct WasmDataSegment {
+  uint32_t InitFlags;
+  // Present if InitFlags & WASM_DATA_SEGMENT_HAS_MEMINDEX.
+  uint32_t MemoryIndex;
+  // Present if InitFlags & WASM_DATA_SEGMENT_IS_PASSIVE == 0.
+  WasmInitExpr Offset;
+
+  ArrayRef<uint8_t> Content;
+  StringRef Name; // from the "segment info" section
+  uint32_t Alignment;
+  uint32_t LinkingFlags;
+  uint32_t Comdat; // from the "comdat info" section
+};
+
+// 3 different element segment modes are encodable. This class is currently
+// only used during decoding (see WasmElemSegment below).
+enum class ElemSegmentMode { Active, Passive, Declarative };
+
+// Represents a Wasm element segment, with some limitations compared the spec:
+// 1) Does not model passive or declarative segments (Segment will end up with
+// an Offset field of i32.const 0)
+// 2) Does not model init exprs (Segment will get an empty Functions list)
+// 3) Does not model types other than basic funcref/externref/exnref (see
+// ValType)
+struct WasmElemSegment {
+  uint32_t Flags;
+  uint32_t TableNumber;
+  ValType ElemKind;
+  WasmInitExpr Offset;
+  std::vector<uint32_t> Functions;
+};
+
+// Represents the location of a Wasm data symbol within a WasmDataSegment, as
+// the index of the segment, and the offset and size within the segment.
+struct WasmDataReference {
+  uint32_t Segment;
+  uint64_t Offset;
+  uint64_t Size;
+};
+
+struct WasmRelocation {
+  uint8_t Type;    // The type of the relocation.
+  uint32_t Index;  // Index into either symbol or type index space.
+  uint64_t Offset; // Offset from the start of the section.
+  int64_t Addend;  // A value to add to the symbol.
+
+  WasmRelocType getType() const { return static_cast<WasmRelocType>(Type); }
+};
+
+struct WasmInitFunc {
+  uint32_t Priority;
+  uint32_t Symbol;
+};
+
+struct WasmSymbolInfo {
+  StringRef Name;
+  uint8_t Kind;
+  uint32_t Flags;
+  // For undefined symbols the module of the import
+  std::optional<StringRef> ImportModule;
+  // For undefined symbols the name of the import
+  std::optional<StringRef> ImportName;
+  // For symbols to be exported from the final module
+  std::optional<StringRef> ExportName;
+  union {
+    // For function, table, or global symbols, the index in function, table, or
+    // global index space.
+    uint32_t ElementIndex;
+    // For a data symbols, the address of the data relative to segment.
+    WasmDataReference DataRef;
+  };
+};
+
+enum class NameType {
+  FUNCTION,
+  GLOBAL,
+  DATA_SEGMENT,
+};
+
+struct WasmDebugName {
+  NameType Type;
+  uint32_t Index;
+  StringRef Name;
+};
+
+// Info from the linking metadata section of a wasm object file.
+struct WasmLinkingData {
+  uint32_t Version;
+  std::vector<WasmInitFunc> InitFunctions;
+  std::vector<StringRef> Comdats;
+  // The linking section also contains a symbol table. This info (represented
+  // in a WasmSymbolInfo struct) is stored inside the WasmSymbol object instead
+  // of in this structure; this allows vectors of WasmSymbols and
+  // WasmLinkingDatas to be reallocated.
+};
+
+struct WasmSignature {
+  SmallVector<ValType, 1> Returns;
+  SmallVector<ValType, 4> Params;
+  // LLVM can parse types other than functions encoded in the type section,
+  // but does not actually model them. Instead a placeholder signature is
+  // created in the Object's signature list.
+  enum { Function, Tag, Placeholder } Kind = Function;
+  // Support empty and tombstone instances, needed by DenseMap.
+  enum { Plain, Empty, Tombstone } State = Plain;
+
+  WasmSignature(SmallVector<ValType, 1> &&InReturns,
+                SmallVector<ValType, 4> &&InParams)
+      : Returns(InReturns), Params(InParams) {}
+  WasmSignature() = default;
+};
+
+// Useful comparison operators
+inline bool operator==(const WasmSignature &LHS, const WasmSignature &RHS) {
+  return LHS.State == RHS.State && LHS.Returns == RHS.Returns &&
+         LHS.Params == RHS.Params;
+}
+
+inline bool operator!=(const WasmSignature &LHS, const WasmSignature &RHS) {
+  return !(LHS == RHS);
+}
+
+inline bool operator==(const WasmGlobalType &LHS, const WasmGlobalType &RHS) {
+  return LHS.Type == RHS.Type && LHS.Mutable == RHS.Mutable;
+}
+
+inline bool operator!=(const WasmGlobalType &LHS, const WasmGlobalType &RHS) {
+  return !(LHS == RHS);
+}
+
+inline bool operator==(const WasmLimits &LHS, const WasmLimits &RHS) {
+  return LHS.Flags == RHS.Flags && LHS.Minimum == RHS.Minimum &&
+         (LHS.Flags & WASM_LIMITS_FLAG_HAS_MAX ? LHS.Maximum == RHS.Maximum
+                                               : true) &&
+         (LHS.Flags & WASM_LIMITS_FLAG_HAS_PAGE_SIZE
+              ? LHS.PageSize == RHS.PageSize
+              : true);
+}
+
+inline bool operator==(const WasmTableType &LHS, const WasmTableType &RHS) {
+  return LHS.ElemType == RHS.ElemType && LHS.Limits == RHS.Limits;
+}
+
+inline llvm::StringRef sectionTypeToString(uint32_t type) {
+#define ECase(X)                                                               \
+  case wasm::WASM_SEC_##X:                                                     \
+    return #X;
+  switch (type) {
+    ECase(CUSTOM);
+    ECase(TYPE);
+    ECase(IMPORT);
+    ECase(FUNCTION);
+    ECase(TABLE);
+    ECase(MEMORY);
+    ECase(GLOBAL);
+    ECase(EXPORT);
+    ECase(START);
+    ECase(ELEM);
+    ECase(CODE);
+    ECase(DATA);
+    ECase(DATACOUNT);
+    ECase(TAG);
+  default:
+    llvm_unreachable("unknown section type");
+  }
+#undef ECase
+}
+
+} // end namespace wasm
+} // end namespace llvm
+
+#endif
diff --git a/include/swift/RemoteInspection/RuntimeHeaders/llvm/BinaryFormat/WasmRelocs.def b/include/swift/RemoteInspection/RuntimeHeaders/llvm/BinaryFormat/WasmRelocs.def
new file mode 100644
index 0000000000000..6f5a946b1c63d
--- /dev/null
+++ b/include/swift/RemoteInspection/RuntimeHeaders/llvm/BinaryFormat/WasmRelocs.def
@@ -0,0 +1,31 @@
+#ifndef WASM_RELOC
+#error "WASM_RELOC must be defined"
+#endif
+
+WASM_RELOC(R_WASM_FUNCTION_INDEX_LEB,      0)
+WASM_RELOC(R_WASM_TABLE_INDEX_SLEB,        1)
+WASM_RELOC(R_WASM_TABLE_INDEX_I32,         2)
+WASM_RELOC(R_WASM_MEMORY_ADDR_LEB,         3)
+WASM_RELOC(R_WASM_MEMORY_ADDR_SLEB,        4)
+WASM_RELOC(R_WASM_MEMORY_ADDR_I32,         5)
+WASM_RELOC(R_WASM_TYPE_INDEX_LEB,          6)
+WASM_RELOC(R_WASM_GLOBAL_INDEX_LEB,        7)
+WASM_RELOC(R_WASM_FUNCTION_OFFSET_I32,     8)
+WASM_RELOC(R_WASM_SECTION_OFFSET_I32,      9)
+WASM_RELOC(R_WASM_TAG_INDEX_LEB,          10)
+WASM_RELOC(R_WASM_MEMORY_ADDR_REL_SLEB,   11)
+WASM_RELOC(R_WASM_TABLE_INDEX_REL_SLEB,   12)
+WASM_RELOC(R_WASM_GLOBAL_INDEX_I32,       13)
+WASM_RELOC(R_WASM_MEMORY_ADDR_LEB64,      14)
+WASM_RELOC(R_WASM_MEMORY_ADDR_SLEB64,     15)
+WASM_RELOC(R_WASM_MEMORY_ADDR_I64,        16)
+WASM_RELOC(R_WASM_MEMORY_ADDR_REL_SLEB64, 17)
+WASM_RELOC(R_WASM_TABLE_INDEX_SLEB64,     18)
+WASM_RELOC(R_WASM_TABLE_INDEX_I64,        19)
+WASM_RELOC(R_WASM_TABLE_NUMBER_LEB,       20)
+WASM_RELOC(R_WASM_MEMORY_ADDR_TLS_SLEB,   21)
+WASM_RELOC(R_WASM_FUNCTION_OFFSET_I64,    22)
+WASM_RELOC(R_WASM_MEMORY_ADDR_LOCREL_I32, 23)
+WASM_RELOC(R_WASM_TABLE_INDEX_REL_SLEB64, 24)
+WASM_RELOC(R_WASM_MEMORY_ADDR_TLS_SLEB64, 25)
+WASM_RELOC(R_WASM_FUNCTION_INDEX_I32,     26)
diff --git a/include/swift/RemoteInspection/RuntimeHeaders/llvm/Support/Error.h b/include/swift/RemoteInspection/RuntimeHeaders/llvm/Support/Error.h
index 2292770a97c4b..c90ef0a88ad01 100644
--- a/include/swift/RemoteInspection/RuntimeHeaders/llvm/Support/Error.h
+++ b/include/swift/RemoteInspection/RuntimeHeaders/llvm/Support/Error.h
@@ -15,7 +15,6 @@
 
 #include "llvm-c/Error.h"
 #include "llvm/ADT/Twine.h"
-#include "llvm/Config/abi-breaking.h"
 #include "llvm/Support/AlignOf.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
diff --git a/include/swift/RemoteInspection/RuntimeInternals.h b/include/swift/RemoteInspection/RuntimeInternals.h
index 52f22df294978..981e6bf106c37 100644
--- a/include/swift/RemoteInspection/RuntimeInternals.h
+++ b/include/swift/RemoteInspection/RuntimeInternals.h
@@ -58,13 +58,13 @@ template <typename Runtime> struct ConcurrentHashMap {
 
 template <typename Runtime> struct ConformanceCacheEntry {
   typename Runtime::StoredPointer Type;
-  typename Runtime::StoredPointer Proto;
+  typename Runtime::StoredSignedPointer Proto;
   typename Runtime::StoredPointer Witness;
 };
 
 template <typename Runtime>
 struct HeapObject {
-  typename Runtime::StoredPointer Metadata;
+  typename Runtime::StoredSignedPointer Metadata;
   typename Runtime::StoredSize RefCounts;
 };
 
@@ -82,8 +82,7 @@ template <typename Runtime>
 struct StackAllocator {
   typename Runtime::StoredPointer LastAllocation;
   typename Runtime::StoredPointer FirstSlab;
-  int32_t NumAllocatedSlabs;
-  bool FirstSlabIsPreallocated;
+  int32_t NumAllocatedSlabsAndFirstSlabIsPreallocated;
 
   struct Slab {
     typename Runtime::StoredPointer Metadata;
@@ -114,6 +113,7 @@ struct ActiveTaskStatusFlags {
   static const uint32_t IsRunning = 0x800;
   static const uint32_t IsEnqueued = 0x1000;
   static const uint32_t IsComplete = 0x2000;
+  static const uint32_t HasTaskDependency = 0x4000;
 };
 
 template <typename Runtime, typename ActiveTaskStatus>
@@ -123,7 +123,8 @@ struct AsyncTaskPrivateStorage {
   StackAllocator<Runtime> Allocator;
   typename Runtime::StoredPointer Local;
   uint32_t Id;
-  uint32_t BasePriority;
+  typename Runtime::StoredSize BasePriority;
+  typename Runtime::StoredPointer DependencyRecord;
 };
 
 template <typename Runtime, typename ActiveTaskStatus>
@@ -131,10 +132,7 @@ struct AsyncTask: Job<Runtime> {
   // On 64-bit, there's a Reserved64 after ResumeContext.
   typename Runtime::StoredPointer ResumeContextAndReserved[
     sizeof(typename Runtime::StoredPointer) == 8 ? 2 : 1];
-  union {
-    AsyncTaskPrivateStorage<Runtime, ActiveTaskStatus> PrivateStorage;
-    typename Runtime::StoredPointer PrivateStorageRaw[14];
-  };
+  AsyncTaskPrivateStorage<Runtime, ActiveTaskStatus> PrivateStorage;
 };
 
 template <typename Runtime>
diff --git a/include/swift/RemoteInspection/TypeLowering.h b/include/swift/RemoteInspection/TypeLowering.h
index c1946d59cead8..ed2c4b5d0393f 100644
--- a/include/swift/RemoteInspection/TypeLowering.h
+++ b/include/swift/RemoteInspection/TypeLowering.h
@@ -373,8 +373,8 @@ class ArrayTypeInfo : public TypeInfo {
 class TypeConverter {
   TypeRefBuilder &Builder;
   std::vector<std::unique_ptr<const TypeInfo>> Pool;
-  llvm::DenseMap<std::pair<const TypeRef *, remote::TypeInfoProvider::IdType>,
-                 const TypeInfo *> Cache;
+  using KeyT = std::pair<const TypeRef *, remote::TypeInfoProvider::IdType>;
+  llvm::DenseMap<KeyT, const TypeInfo *> Cache;
   llvm::DenseSet<const TypeRef *> RecursionCheck;
   llvm::DenseMap<std::pair<unsigned, unsigned>,
                  const ReferenceTypeInfo *> ReferenceCache;
@@ -391,9 +391,25 @@ class TypeConverter {
   const TypeInfo *DefaultActorStorageTI = nullptr;
   const TypeInfo *EmptyTI = nullptr;
 
+  /// Used for lightweight error handling. We don't have access to
+  /// llvm::Expected<> here, so TypeConverter just stores a pointer to the last
+  /// encountered error instead that is stored in the cache.
+  using TCError = std::pair<const char *, const TypeRef *>;
+  TCError LastError = {nullptr, nullptr};
+  std::unique_ptr<llvm::DenseMap<KeyT, TCError>> ErrorCache;
+
 public:
   explicit TypeConverter(TypeRefBuilder &Builder) : Builder(Builder) {}
 
+  /// Called by LLDB.
+  void enableErrorCache() {
+    ErrorCache = std::make_unique<llvm::DenseMap<KeyT, TCError>>();
+  }
+  void setError(const char *msg, const TypeRef *TR) { LastError = {msg, TR}; }
+
+  /// Retreive the error and reset it.
+  std::string takeLastError();
+
   TypeRefBuilder &getBuilder() { return Builder; }
 
   /// Tests if the type is concrete enough that its size is known.
@@ -474,8 +490,10 @@ class RecordTypeInfoBuilder {
     : TC(TC), Size(0), Alignment(1), NumExtraInhabitants(0),
       BitwiseTakable(true), Kind(Kind), Empty(true), Invalid(false) {}
 
-  bool isInvalid() const {
-    return Invalid;
+  bool isInvalid() const { return Invalid; }
+  void markInvalid(const char *msg, const TypeRef *TR = nullptr) {
+    Invalid = true;
+    TC.setError(msg, TR);
   }
 
   unsigned addField(unsigned fieldSize, unsigned fieldAlignment,
diff --git a/include/swift/RemoteInspection/TypeRef.h b/include/swift/RemoteInspection/TypeRef.h
index 593a923d35370..354492a497b79 100644
--- a/include/swift/RemoteInspection/TypeRef.h
+++ b/include/swift/RemoteInspection/TypeRef.h
@@ -238,10 +238,6 @@ class alignas(8) TypeRef {
   const TypeRef *subst(TypeRefBuilder &Builder,
                        const GenericArgumentMap &Subs) const;
 
-  const TypeRef *subst(TypeRefBuilder &Builder,
-                       const GenericArgumentMap &Subs,
-                       bool &DidSubstitute) const;
-
   std::optional<GenericArgumentMap> getSubstMap() const;
 
   virtual ~TypeRef() = default;
@@ -420,6 +416,65 @@ class TupleTypeRef final : public TypeRef {
   }
 };
 
+class PackTypeRef final : public TypeRef {
+protected:
+  std::vector<const TypeRef *> Elements;
+
+  static TypeRefID Profile(const std::vector<const TypeRef *> &Elements) {
+    TypeRefID ID;
+    for (auto Element : Elements)
+      ID.addPointer(Element);
+    return ID;
+  }
+
+public:
+  PackTypeRef(std::vector<const TypeRef *> Elements)
+      : TypeRef(TypeRefKind::Pack), Elements(std::move(Elements)) {}
+
+  template <typename Allocator>
+  static const PackTypeRef *create(Allocator &A,
+                                    std::vector<const TypeRef *> Elements) {
+    FIND_OR_CREATE_TYPEREF(A, PackTypeRef, Elements);
+  }
+
+  const std::vector<const TypeRef *> &getElements() const { return Elements; };
+
+  static bool classof(const TypeRef *TR) {
+    return TR->getKind() == TypeRefKind::Pack;
+  }
+};
+
+class PackExpansionTypeRef final : public TypeRef {
+protected:
+  const TypeRef *Pattern;
+  const TypeRef *Count;
+
+  static TypeRefID Profile(const TypeRef *Pattern, const TypeRef *Count) {
+    TypeRefID ID;
+    ID.addPointer(Pattern);
+    ID.addPointer(Count);
+    return ID;
+  }
+
+public:
+  PackExpansionTypeRef( const TypeRef *Pattern, const TypeRef *Count)
+      : TypeRef(TypeRefKind::PackExpansion), Pattern(Pattern), Count(Count) {}
+
+  template <typename Allocator>
+  static const PackExpansionTypeRef *create(Allocator &A,
+                                 const TypeRef *Pattern, const TypeRef *Count) {
+    FIND_OR_CREATE_TYPEREF(A, PackExpansionTypeRef, Pattern, Count);
+  }
+
+  const TypeRef *getPattern() const { return Pattern; }
+
+  const TypeRef *getCount() const { return Count; }
+
+  static bool classof(const TypeRef *TR) {
+    return TR->getKind() == TypeRefKind::PackExpansion;
+  }
+};
+
 class OpaqueArchetypeTypeRef final : public TypeRef {
   std::string ID;
   std::string Description;
@@ -676,6 +731,64 @@ class ConstrainedExistentialTypeRef final : public TypeRef {
   }
 };
 
+class SymbolicExtendedExistentialTypeRef final : public TypeRef {
+  const ProtocolCompositionTypeRef *Protocol;
+  std::vector<TypeRefRequirement> Requirements;
+  std::vector<const TypeRef *> Arguments;
+  ExtendedExistentialTypeShapeFlags Flags;
+
+  static TypeRefID Profile(const ProtocolCompositionTypeRef *Protocol,
+                           llvm::ArrayRef<TypeRefRequirement> Requirements,
+                           llvm::ArrayRef<const TypeRef *> Arguments,
+                           ExtendedExistentialTypeShapeFlags Flags) {
+    TypeRefID ID;
+    ID.addPointer(Protocol);
+    for (auto reqt : Requirements) {
+      ID.addPointer(reqt.getFirstType());
+      if (reqt.getKind() != RequirementKind::Layout)
+        ID.addPointer(reqt.getSecondType());
+      else
+        ID.addInteger(
+            unsigned(0)); // FIXME: Layout constraints aren't implemented yet
+      ID.addInteger(unsigned(reqt.getKind()));
+    }
+
+    for (auto &Arg : Arguments)
+      ID.addPointer(Arg);
+    return ID;
+  }
+
+public:
+  SymbolicExtendedExistentialTypeRef(
+      const ProtocolCompositionTypeRef *Protocol,
+      llvm::ArrayRef<TypeRefRequirement> Requirements,
+      llvm::ArrayRef<const TypeRef *> Args,
+      ExtendedExistentialTypeShapeFlags Flags)
+      : TypeRef(TypeRefKind::SymbolicExtendedExistential), Protocol(Protocol),
+        Requirements(Requirements), Arguments(Args), Flags(Flags) {}
+
+  template <typename Allocator>
+  static const SymbolicExtendedExistentialTypeRef *
+  create(Allocator &A, const ProtocolCompositionTypeRef *Protocol,
+         llvm::ArrayRef<TypeRefRequirement> Requirements,
+         llvm::ArrayRef<const TypeRef *> Args,
+         ExtendedExistentialTypeShapeFlags Flags) {
+    FIND_OR_CREATE_TYPEREF(A, SymbolicExtendedExistentialTypeRef, Protocol,
+                           Requirements, Args, Flags);
+  }
+
+  const ProtocolCompositionTypeRef *getProtocol() const { return Protocol; }
+  llvm::ArrayRef<TypeRefRequirement> getRequirements() const {
+    return Requirements;
+  }
+  llvm::ArrayRef<const TypeRef *> getArguments() const { return Arguments; }
+  ExtendedExistentialTypeShapeFlags getFlags() const { return Flags; }
+
+  static bool classof(const TypeRef *TR) {
+    return TR->getKind() == TypeRefKind::SymbolicExtendedExistential;
+  }
+};
+
 class MetatypeTypeRef final : public TypeRef {
   const TypeRef *InstanceType;
   bool WasAbstract;
diff --git a/include/swift/RemoteInspection/TypeRefBuilder.h b/include/swift/RemoteInspection/TypeRefBuilder.h
index a6b44e69fdb98..2b07d09469042 100644
--- a/include/swift/RemoteInspection/TypeRefBuilder.h
+++ b/include/swift/RemoteInspection/TypeRefBuilder.h
@@ -63,16 +63,21 @@ class ReflectionSection {
 
   size_t size() const { return Size; }
 
-  bool containsRemoteAddress(uint64_t remoteAddr, uint64_t size) const {
-    return Start.getAddressData() <= remoteAddr &&
-           remoteAddr + size <= Start.getAddressData() + Size;
+  bool containsRemoteAddress(remote::RemoteAddress remoteAddr,
+                             uint64_t size) const {
+    if (Start.getRemoteAddress().getAddressSpace() !=
+        remoteAddr.getAddressSpace())
+      return false;
+
+    return Start.getRemoteAddress() <= remoteAddr &&
+           remoteAddr + size <= Start.getRemoteAddress() + Size;
   }
 
   template <typename U>
-  RemoteRef<U> getRemoteRef(uint64_t remoteAddr) const {
+  RemoteRef<U> getRemoteRef(remote::RemoteAddress remoteAddr) const {
     assert(containsRemoteAddress(remoteAddr, sizeof(U)));
     auto localAddr = (uint64_t)(uintptr_t)Start.getLocalBuffer() +
-                     (remoteAddr - Start.getAddressData());
+                     (remoteAddr - Start.getRemoteAddress());
 
     return RemoteRef<U>(remoteAddr, (const U *)localAddr);
   }
@@ -124,7 +129,7 @@ class ReflectionSectionIteratorBase {
 
   RemoteRef<Descriptor> operator*() const {
     assert(Size > 0);
-    return RemoteRef<Descriptor>(Cur.getAddressData(),
+    return RemoteRef<Descriptor>(Cur.getRemoteAddress(),
                                  (const Descriptor *)Cur.getLocalBuffer());
   }
 
@@ -414,6 +419,15 @@ class TypeRefBuilder {
 
   std::vector<std::unique_ptr<const GenericSignatureRef>> SignatureRefPool;
 
+  /// This builder doesn't perform "on the fly" substitutions, so we preserve
+  /// all pack expansions. We still need an active expansion stack though,
+  /// for the dummy implementation of these methods:
+  /// - beginPackExpansion()
+  /// - advancePackExpansion()
+  /// - createExpandedPackElement()
+  /// - endPackExpansion()
+  std::vector<const TypeRef *> ActivePackExpansions;
+
   TypeConverter TC;
 
 #define TYPEREF(Id, Parent) \
@@ -490,7 +504,8 @@ class TypeRefBuilder {
 
     /// Get the raw capture descriptor for a remote capture descriptor
     /// address.
-    RemoteRef<CaptureDescriptor> getCaptureDescriptor(uint64_t RemoteAddress);
+    RemoteRef<CaptureDescriptor>
+    getCaptureDescriptor(remote::RemoteAddress RemoteAddress);
 
     /// Get the unsubstituted capture types for a closure context.
     ClosureContextInfo getClosureContextInfo(RemoteRef<CaptureDescriptor> CD);
@@ -503,11 +518,11 @@ class TypeRefBuilder {
                                      const std::string &Member,
                                      StringRef Protocol);
 
-    RemoteRef<char> readTypeRef(uint64_t remoteAddr);
+    RemoteRef<char> readTypeRef(remote::RemoteAddress remoteAddr);
 
     template <typename Record, typename Field>
     RemoteRef<char> readTypeRef(RemoteRef<Record> record, const Field &field) {
-      uint64_t remoteAddr = record.resolveRelativeFieldData(field);
+      remote::RemoteAddress remoteAddr = record.resolveRelativeFieldData(field);
 
       return readTypeRef(remoteAddr);
     }
@@ -535,7 +550,8 @@ class TypeRefBuilder {
                                StringRef searchName);
 
     std::optional<std::reference_wrapper<const ReflectionInfo>>
-    findReflectionInfoWithTypeRefContainingAddress(uint64_t remoteAddr);
+    findReflectionInfoWithTypeRefContainingAddress(
+        remote::RemoteAddress remoteAddr);
 
     std::vector<ReflectionInfo> ReflectionInfos;
 
@@ -546,8 +562,7 @@ class TypeRefBuilder {
     llvm::DenseSet<size_t> ProcessedReflectionInfoIndexes;
 
     /// Cache for capture descriptor lookups.
-    std::unordered_map<uint64_t /* remote address*/,
-                       RemoteRef<CaptureDescriptor>>
+    std::unordered_map<remote::RemoteAddress, RemoteRef<CaptureDescriptor>>
         CaptureDescriptorsByAddress;
     uint32_t CaptureDescriptorsByAddressLastReflectionInfoCache = 0;
 
@@ -556,7 +571,7 @@ class TypeRefBuilder {
         FieldTypeInfoCache;
 
     /// Cache for normalized reflection name lookups.
-    std::unordered_map<uint64_t /* remote address */,
+    std::unordered_map<remote::RemoteAddress /* remote address */,
                        std::optional<std::string>>
         NormalizedReflectionNameCache;
 
@@ -1098,8 +1113,9 @@ class TypeRefBuilder {
     // Try to resolve to the underlying type, if we can.
     if (opaqueDescriptor->getKind() ==
         Node::Kind::OpaqueTypeDescriptorSymbolicReference) {
-      auto underlyingTy =
-          OpaqueUnderlyingTypeReader(opaqueDescriptor->getIndex(), ordinal);
+      auto [address, space] = opaqueDescriptor->getRemoteAddress();
+      auto underlyingTy = OpaqueUnderlyingTypeReader(
+          remote::RemoteAddress(address, space), ordinal);
 
       if (!underlyingTy)
         return nullptr;
@@ -1133,8 +1149,7 @@ class TypeRefBuilder {
   }
 
   const TypeRef *createPackType(llvm::ArrayRef<const TypeRef *> elements) {
-    // FIXME: Remote mirrors support for variadic generics.
-    return nullptr;
+    return PackTypeRef::create(*this, elements);
   }
 
   const TypeRef *createSILPackType(llvm::ArrayRef<const TypeRef *> elements,
@@ -1144,21 +1159,22 @@ class TypeRefBuilder {
   }
 
   size_t beginPackExpansion(const TypeRef *countType) {
-    // FIXME: Remote mirrors support for variadic generics.
-    return 0;
+    ActivePackExpansions.push_back(countType);
+    return 1;
   }
 
   void advancePackExpansion(size_t index) {
-    // FIXME: Remote mirrors support for variadic generics.
+    assert(index == 0);
   }
 
   const TypeRef *createExpandedPackElement(const TypeRef *patternType) {
-    // FIXME: Remote mirrors support for variadic generics.
-    return nullptr;
+    assert(!ActivePackExpansions.empty());
+    auto countType = ActivePackExpansions.back();
+    return PackExpansionTypeRef::create(*this, patternType, countType);
   }
 
   void endPackExpansion() {
-    // FIXME: Remote mirrors support for variadic generics.
+    ActivePackExpansions.pop_back();
   }
 
   const FunctionTypeRef *createFunctionType(
@@ -1274,8 +1290,28 @@ class TypeRefBuilder {
   const TypeRef *
   createSymbolicExtendedExistentialType(NodePointer shapeNode,
                                         llvm::ArrayRef<const TypeRef *> args) {
-    // Can't handle this here.
-    return nullptr;
+    // Non-unique shape symbols start with an offset to a cache variable, right
+    // before the shape. Metadata pointers point directly to the shape, but when
+    // reading from a shape symbol, this needs to be corrected.
+    uint32_t offset = 0;
+    if (shapeNode->getKind() ==
+        Node::Kind::NonUniqueExtendedExistentialTypeShapeSymbolicReference)
+      offset = sizeof(uint32_t);
+    auto [address, space] = shapeNode->getRemoteAddress();
+    remote::RemoteAddress shape(address, space);
+    shape += offset;
+
+    return OpaqueShapeReader(
+        shape,
+        [&](unsigned shapeArgumentCount)
+            -> std::optional<std::vector<const TypeRef *>> {
+          if (args.size() != shapeArgumentCount)
+            return std::nullopt;
+          if (llvm::any_of(
+                  args, [](const TypeRef *arg) { return !arg->isConcrete(); }))
+            return std::nullopt;
+          return args;
+        });
   }
 
   const ExistentialMetatypeTypeRef *createExistentialMetatypeType(
@@ -1303,8 +1339,7 @@ class TypeRefBuilder {
 
   const DependentMemberTypeRef *
   createDependentMemberType(const std::string &member, const TypeRef *base) {
-    // Should not have unresolved dependent member types here.
-    return nullptr;
+    return DependentMemberTypeRef::create(*this, member, base, "");
   }
 
   const DependentMemberTypeRef *
@@ -1448,7 +1483,7 @@ class TypeRefBuilder {
   llvm::DenseSet<size_t> ProcessedReflectionInfoIndexes;
 
 public:
-  RemoteRef<char> readTypeRef(uint64_t remoteAddr) {
+  RemoteRef<char> readTypeRef(remote::RemoteAddress remoteAddr) {
     return RDF.readTypeRef(remoteAddr);
   }
   template <typename Record, typename Field>
@@ -1462,7 +1497,7 @@ class TypeRefBuilder {
 private:
   using RefDemangler = std::function<Demangle::Node *(RemoteRef<char>, bool)>;
   using UnderlyingTypeReader =
-      std::function<const TypeRef *(uint64_t, unsigned)>;
+      std::function<const TypeRef *(remote::RemoteAddress, unsigned)>;
   using ByteReader = std::function<remote::MemoryReader::ReadBytesResult(
       remote::RemoteAddress, unsigned)>;
   using StringReader =
@@ -1470,6 +1505,13 @@ class TypeRefBuilder {
   using PointerReader =
       std::function<std::optional<remote::RemoteAbsolutePointer>(
           remote::RemoteAddress, unsigned)>;
+  using ShapeReader = std::function<const TypeRef *(
+      remote::RemoteAbsolutePointer,
+      std::function<std::optional<std::vector<const TypeRef *>>(unsigned)>)>;
+
+  using PointerSymbolResolver =
+      std::function<std::optional<remote::RemoteAbsolutePointer>(
+          remote::RemoteAddress)>;
   using DynamicSymbolResolver =
       std::function<std::optional<remote::RemoteAbsolutePointer>(
           remote::RemoteAddress)>;
@@ -1502,6 +1544,8 @@ class TypeRefBuilder {
   ByteReader OpaqueByteReader;
   StringReader OpaqueStringReader;
   PointerReader OpaquePointerReader;
+  ShapeReader OpaqueShapeReader;
+  PointerSymbolResolver OpaquePointerSymbolResolver;
   DynamicSymbolResolver OpaqueDynamicSymbolResolver;
   IntVariableReader OpaqueIntVariableReader;
 
@@ -1519,7 +1563,7 @@ class TypeRefBuilder {
                                  useOpaqueTypeSymbolicReferences);
         }),
         OpaqueUnderlyingTypeReader(
-            [&reader](uint64_t descriptorAddr,
+            [&reader](remote::RemoteAddress descriptorAddr,
                       unsigned ordinal) -> const TypeRef * {
               return reader
                   .readUnderlyingTypeForOpaqueTypeDescriptor(descriptorAddr,
@@ -1540,6 +1584,18 @@ class TypeRefBuilder {
                 -> std::optional<remote::RemoteAbsolutePointer> {
               return reader.Reader->readPointer(address, size);
             }),
+        OpaqueShapeReader(
+            [&reader](remote::RemoteAbsolutePointer pointer,
+                      std::function<std::optional<std::vector<const TypeRef *>>(
+                          unsigned)>
+                          getArgs) -> const TypeRef * {
+              return reader.readTypeFromShape(pointer, getArgs);
+            }),
+        OpaquePointerSymbolResolver(
+            [&reader](remote::RemoteAddress address)
+                -> std::optional<remote::RemoteAbsolutePointer> {
+              return reader.Reader->resolvePointerAsSymbol(address);
+            }),
         OpaqueDynamicSymbolResolver(
             [&reader](remote::RemoteAddress address)
                 -> std::optional<remote::RemoteAbsolutePointer> {
@@ -1607,7 +1663,8 @@ class TypeRefBuilder {
 
   /// Get the raw capture descriptor for a remote capture descriptor
   /// address.
-  RemoteRef<CaptureDescriptor> getCaptureDescriptor(uint64_t RemoteAddress) {
+  RemoteRef<CaptureDescriptor>
+  getCaptureDescriptor(remote::RemoteAddress RemoteAddress) {
     return RDF.getCaptureDescriptor(RemoteAddress);
   }
 
@@ -1688,8 +1745,12 @@ class TypeRefBuilder {
         auto opaqueTypeChildDemangleTree = childDemangleTree->getFirstChild();
         if (opaqueTypeChildDemangleTree->getKind() ==
             Node::Kind::OpaqueTypeDescriptorSymbolicReference) {
+          // FIXME: Node should carry a data structure that can fit a remote
+          // address. For now assume that this is a process address.
+          auto [address, space] =
+              opaqueTypeChildDemangleTree->getRemoteAddress();
           extractOpaqueTypeProtocolRequirements<ObjCInteropKind, PointerSize>(
-              opaqueTypeChildDemangleTree->getIndex(),
+              remote::RemoteAddress(address, space),
               opaqueTypeConformanceRequirements, sameTypeRequirements);
         }
       }
@@ -1699,7 +1760,7 @@ class TypeRefBuilder {
 private:
   struct ContextNameInfo {
     std::string name;
-    uintptr_t descriptorAddress;
+    remote::RemoteAddress descriptorAddress;
     bool isAnonymous;
 
     ~ContextNameInfo() {}
@@ -1722,10 +1783,10 @@ class TypeRefBuilder {
           OpaqueDynamicSymbolResolver(dynamicSymbolResolver) {}
 
     std::optional<std::string> readProtocolNameFromProtocolDescriptor(
-        uintptr_t protocolDescriptorAddress) {
+        remote::RemoteAddress protocolDescriptorAddress) {
       std::string protocolName;
       auto protocolDescriptorBytes = OpaqueByteReader(
-          remote::RemoteAddress(protocolDescriptorAddress),
+          protocolDescriptorAddress,
           sizeof(ExternalProtocolDescriptor<ObjCInteropKind, PointerSize>));
       if (!protocolDescriptorBytes.get()) {
         Error = "Error reading protocol descriptor.";
@@ -1738,11 +1799,11 @@ class TypeRefBuilder {
 
       // Compute the address of the protocol descriptor's name field and read
       // the offset
-      auto protocolNameOffsetAddress = detail::applyRelativeOffset(
-          (const char *)protocolDescriptorAddress,
-          (int32_t)protocolDescriptor->getNameOffset());
-      auto protocolNameOffsetBytes = OpaqueByteReader(
-          remote::RemoteAddress(protocolNameOffsetAddress), sizeof(uint32_t));
+      auto protocolNameOffsetAddress =
+          protocolDescriptorAddress.applyRelativeOffset(
+              (int32_t)protocolDescriptor->getNameOffset());
+      auto protocolNameOffsetBytes =
+          OpaqueByteReader(protocolNameOffsetAddress, sizeof(uint32_t));
       if (!protocolNameOffsetBytes.get()) {
         Error = "Failed to read type name offset in a protocol descriptor.";
         return std::nullopt;
@@ -1751,74 +1812,71 @@ class TypeRefBuilder {
 
       // Using the offset above, compute the address of the name field itsel
       // and read it.
-      auto protocolNameAddress =
-          detail::applyRelativeOffset((const char *)protocolNameOffsetAddress,
-                                      (int32_t)*protocolNameOffset);
-      OpaqueStringReader(remote::RemoteAddress(protocolNameAddress),
-                         protocolName);
+      auto protocolNameAddress = protocolNameOffsetAddress.applyRelativeOffset(
+          (int32_t)*protocolNameOffset);
+      OpaqueStringReader(protocolNameAddress, protocolName);
       return protocolName;
     }
 
     std::optional<std::string> readTypeNameFromTypeDescriptor(
         const ExternalTypeContextDescriptor<ObjCInteropKind, PointerSize>
             *typeDescriptor,
-        uintptr_t typeDescriptorAddress) {
-      auto typeNameOffsetAddress =
-          detail::applyRelativeOffset((const char *)typeDescriptorAddress,
-                                      (int32_t)typeDescriptor->getNameOffset());
-      auto typeNameOffsetBytes = OpaqueByteReader(
-          remote::RemoteAddress(typeNameOffsetAddress), sizeof(uint32_t));
+        remote::RemoteAddress typeDescriptorAddress) {
+      auto typeNameOffsetAddress = typeDescriptorAddress.applyRelativeOffset(
+          (int32_t)typeDescriptor->getNameOffset());
+      auto typeNameOffsetBytes =
+          OpaqueByteReader(typeNameOffsetAddress, sizeof(uint32_t));
       if (!typeNameOffsetBytes.get()) {
         Error = "Failed to read type name offset in a type descriptor.";
         return std::nullopt;
       }
       auto typeNameOffset = (const uint32_t *)typeNameOffsetBytes.get();
-      auto typeNameAddress = detail::applyRelativeOffset(
-          (const char *)typeNameOffsetAddress, (int32_t)*typeNameOffset);
+      auto typeNameAddress =
+          typeNameOffsetAddress.applyRelativeOffset((int32_t)*typeNameOffset);
       std::string typeName;
-      OpaqueStringReader(remote::RemoteAddress(typeNameAddress), typeName);
+      OpaqueStringReader(typeNameAddress, typeName);
       return typeName;
     }
 
     std::optional<std::string> readModuleNameFromModuleDescriptor(
         const ExternalModuleContextDescriptor<ObjCInteropKind, PointerSize>
             *moduleDescriptor,
-        uintptr_t moduleDescriptorAddress) {
-      auto parentNameOffsetAddress = detail::applyRelativeOffset(
-          (const char *)moduleDescriptorAddress,
-          (int32_t)moduleDescriptor->getNameOffset());
-      auto parentNameOffsetBytes = OpaqueByteReader(
-          remote::RemoteAddress(parentNameOffsetAddress), sizeof(uint32_t));
+        remote::RemoteAddress moduleDescriptorAddress) {
+      auto parentNameOffsetAddress =
+          moduleDescriptorAddress.applyRelativeOffset(
+              (int32_t)moduleDescriptor->getNameOffset());
+      auto parentNameOffsetBytes =
+          OpaqueByteReader(parentNameOffsetAddress, sizeof(uint32_t));
       if (!parentNameOffsetBytes.get()) {
         Error = "Failed to read parent name offset in a module descriptor.";
         return std::nullopt;
       }
       auto parentNameOffset = (const uint32_t *)parentNameOffsetBytes.get();
-      auto parentNameAddress = detail::applyRelativeOffset(
-          (const char *)parentNameOffsetAddress, (int32_t)*parentNameOffset);
+      auto parentNameAddress = parentNameOffsetAddress.applyRelativeOffset(
+          (int32_t)*parentNameOffset);
       std::string parentName;
-      OpaqueStringReader(remote::RemoteAddress(parentNameAddress), parentName);
+      OpaqueStringReader(parentNameAddress, parentName);
       return parentName;
     }
 
     std::optional<std::string> readAnonymousNameFromAnonymousDescriptor(
         const ExternalAnonymousContextDescriptor<ObjCInteropKind, PointerSize>
             *anonymousDescriptor,
-        uintptr_t anonymousDescriptorAddress) {
+        remote::RemoteAddress anonymousDescriptorAddress) {
       if (!anonymousDescriptor->hasMangledName()) {
         std::stringstream stream;
-        stream << "(unknown context at $" << std::hex
-               << anonymousDescriptorAddress << ")";
+        stream << "(unknown context at $"
+               << anonymousDescriptorAddress.getDescription() << ")";
         return stream.str();
       }
       return std::nullopt;
     }
 
     std::optional<std::string>
-    readFullyQualifiedTypeName(uintptr_t typeDescriptorTarget) {
+    readFullyQualifiedTypeName(remote::RemoteAddress typeDescriptorTarget) {
       std::string typeName;
       auto contextTypeDescriptorBytes = OpaqueByteReader(
-          remote::RemoteAddress(typeDescriptorTarget),
+          typeDescriptorTarget,
           sizeof(ExternalContextDescriptor<ObjCInteropKind, PointerSize>));
       if (!contextTypeDescriptorBytes.get()) {
         Error = "Failed to read context descriptor.";
@@ -1852,17 +1910,16 @@ class TypeRefBuilder {
       return constructFullyQualifiedNameFromContextChain(contextNameChain);
     }
 
-    std::optional<std::string>
-    readFullyQualifiedProtocolName(uintptr_t protocolDescriptorTarget) {
+    std::optional<std::string> readFullyQualifiedProtocolName(
+        remote::RemoteAddress protocolDescriptorTarget) {
       std::optional<std::string> protocolName;
       // Set low bit indicates that this is an indirect
       // reference
       if (protocolDescriptorTarget & 0x1) {
         auto adjustedProtocolDescriptorTarget = protocolDescriptorTarget & ~0x1;
-        if (auto symbol = OpaquePointerReader(
-                remote::RemoteAddress(adjustedProtocolDescriptorTarget),
-                PointerSize)) {
-          if (!symbol->getSymbol().empty()) {
+        if (auto symbol = OpaquePointerReader(adjustedProtocolDescriptorTarget,
+                                              PointerSize)) {
+          if (!symbol->getSymbol().empty() && symbol->getOffset() == 0) {
             Demangle::Context Ctx;
             auto demangledRoot =
                 Ctx.demangleSymbolAsNode(symbol->getSymbol().str());
@@ -1873,7 +1930,7 @@ class TypeRefBuilder {
                 nodeToString(demangledRoot->getChild(0)->getChild(0));
           } else {
             // This is an absolute address of a protocol descriptor
-            auto protocolDescriptorAddress = (uintptr_t)symbol->getOffset();
+            auto protocolDescriptorAddress = symbol->getResolvedAddress();
             protocolName = readFullyQualifiedProtocolNameFromProtocolDescriptor(
                 protocolDescriptorAddress);
           }
@@ -1893,13 +1950,13 @@ class TypeRefBuilder {
   private:
     std::optional<std::string>
     readFullyQualifiedProtocolNameFromProtocolDescriptor(
-        uintptr_t protocolDescriptorAddress) {
+        remote::RemoteAddress protocolDescriptorAddress) {
       std::optional<std::string> protocolName =
           readProtocolNameFromProtocolDescriptor(protocolDescriptorAddress);
 
       // Read the protocol conformance descriptor itself
       auto protocolContextDescriptorBytes = OpaqueByteReader(
-          remote::RemoteAddress(protocolDescriptorAddress),
+          protocolDescriptorAddress,
           sizeof(ExternalContextDescriptor<ObjCInteropKind, PointerSize>));
       if (!protocolContextDescriptorBytes.get()) {
         return std::nullopt;
@@ -1917,23 +1974,22 @@ class TypeRefBuilder {
       return constructFullyQualifiedNameFromContextChain(contextNameChain);
     }
 
-    uintptr_t getParentDescriptorAddress(
-        uintptr_t contextDescriptorAddress,
+    remote::RemoteAddress getParentDescriptorAddress(
+        remote::RemoteAddress contextDescriptorAddress,
         const ExternalContextDescriptor<ObjCInteropKind, PointerSize>
             *contextDescriptor) {
-      auto parentOffsetAddress = detail::applyRelativeOffset(
-          (const char *)contextDescriptorAddress,
+      auto parentOffsetAddress = contextDescriptorAddress.applyRelativeOffset(
           (int32_t)contextDescriptor->getParentOffset());
-      auto parentOfsetBytes = OpaqueByteReader(
-          remote::RemoteAddress(parentOffsetAddress), sizeof(uint32_t));
+      auto parentOfsetBytes =
+          OpaqueByteReader(parentOffsetAddress, sizeof(uint32_t));
       auto parentFieldOffset = (const int32_t *)parentOfsetBytes.get();
-      auto parentTargetAddress = detail::applyRelativeOffset(
-          (const char *)parentOffsetAddress, *parentFieldOffset);
+      auto parentTargetAddress =
+          parentOffsetAddress.applyRelativeOffset(*parentFieldOffset);
       return parentTargetAddress;
     }
 
     std::optional<ContextNameInfo>
-    getContextName(uintptr_t contextDescriptorAddress,
+    getContextName(remote::RemoteAddress contextDescriptorAddress,
                    const ExternalContextDescriptor<ObjCInteropKind, PointerSize>
                        *contextDescriptor) {
       if (auto moduleDescriptor = dyn_cast<
@@ -1979,7 +2035,7 @@ class TypeRefBuilder {
     }
 
     void getParentContextChain(
-        uintptr_t contextDescriptorAddress,
+        remote::RemoteAddress contextDescriptorAddress,
         const ExternalContextDescriptor<ObjCInteropKind, PointerSize>
             *contextDescriptor,
         std::vector<ContextNameInfo> &chain) {
@@ -1987,10 +2043,10 @@ class TypeRefBuilder {
           contextDescriptorAddress, contextDescriptor);
 
       auto addParentNameAndRecurse =
-          [&](uintptr_t parentContextDescriptorAddress,
+          [&](remote::RemoteAddress parentContextDescriptorAddress,
               std::vector<ContextNameInfo> &chain) -> void {
         auto parentContextDescriptorBytes = OpaqueByteReader(
-            remote::RemoteAddress(parentContextDescriptorAddress),
+            parentContextDescriptorAddress,
             sizeof(ExternalContextDescriptor<ObjCInteropKind, PointerSize>));
         if (!parentContextDescriptorBytes.get()) {
           Error = "Failed to read context descriptor.";
@@ -2014,10 +2070,9 @@ class TypeRefBuilder {
       // Set low bit indicates that this is an indirect reference
       if (parentDescriptorAddress & 0x1) {
         auto adjustedParentTargetAddress = parentDescriptorAddress & ~0x1;
-        if (auto symbol = OpaquePointerReader(
-                remote::RemoteAddress(adjustedParentTargetAddress),
-                PointerSize)) {
-          if (!symbol->getSymbol().empty()) {
+        if (auto symbol =
+                OpaquePointerReader(adjustedParentTargetAddress, PointerSize)) {
+          if (!symbol->getSymbol().empty() && symbol->getOffset() == 0) {
             Demangle::Context Ctx;
             auto demangledRoot =
                 Ctx.demangleSymbolAsNode(symbol->getSymbol().str());
@@ -2062,8 +2117,9 @@ class TypeRefBuilder {
             lastContext ? false : contextNameChain[i + 1].isAnonymous;
         if (nextContextIsAnonymous && !currentContextIsAnonymous) {
           std::stringstream stream;
-          stream << "(" << contextNameInfo.name << " in $" << std::hex
-                 << contextNameChain[i + 1].descriptorAddress << ")";
+          stream << "(" << contextNameInfo.name << " in $"
+                 << contextNameChain[i + 1].descriptorAddress.getDescription()
+                 << ")";
           reversedQualifiedTypeNameMembers.push_back(stream.str());
           skipNext = true;
         } else if (nextContextIsAnonymous && currentContextIsAnonymous) {
@@ -2094,11 +2150,11 @@ class TypeRefBuilder {
   template <template <typename Runtime> class ObjCInteropKind,
             unsigned PointerSize>
   void extractOpaqueTypeProtocolRequirements(
-      uintptr_t opaqueTypeDescriptorAddress,
+      remote::RemoteAddress opaqueTypeDescriptorAddress,
       std::vector<std::string> &protocolRequirements,
       std::vector<TypeAliasInfo> &sameTypeRequirements) {
     auto opaqueTypeDescriptorBytes = OpaqueByteReader(
-        remote::RemoteAddress(opaqueTypeDescriptorAddress),
+        opaqueTypeDescriptorAddress,
         sizeof(ExternalOpaqueTypeDescriptor<ObjCInteropKind, PointerSize>));
     if (!opaqueTypeDescriptorBytes.get()) {
       return;
@@ -2116,16 +2172,15 @@ class TypeRefBuilder {
     // is an offset to a TypeRef string, read it.
     auto readRequirementTypeRefAddress =
         [&](uintptr_t offsetFromOpaqueDescBase,
-            uintptr_t requirementAddress) -> uintptr_t {
+            uintptr_t requirementAddress) -> remote::RemoteAddress {
       std::string typeRefString = "";
       auto fieldOffsetOffset = requirementAddress + offsetFromOpaqueDescBase -
                                (uintptr_t)opaqueTypeDescriptor;
       auto fieldOffsetAddress = opaqueTypeDescriptorAddress + fieldOffsetOffset;
-      auto fieldOffsetBytes = OpaqueByteReader(
-          remote::RemoteAddress(fieldOffsetAddress), sizeof(uint32_t));
+      auto fieldOffsetBytes =
+          OpaqueByteReader(fieldOffsetAddress, sizeof(uint32_t));
       auto fieldOffset = (const int32_t *)fieldOffsetBytes.get();
-      auto fieldAddress = detail::applyRelativeOffset(
-          (const char *)fieldOffsetAddress, *fieldOffset);
+      auto fieldAddress = fieldOffsetAddress.applyRelativeOffset(*fieldOffset);
       return fieldAddress;
     };
 
@@ -2143,9 +2198,9 @@ class TypeRefBuilder {
 
         // Compute the address of the protocol descriptor by following the
         // offset
-        auto protocolDescriptorAddress = detail::applyRelativeOffset(
-            (const char *)protocolDescriptorOffsetAddress,
-            protocolDescriptorOffsetValue);
+        auto protocolDescriptorAddress =
+            protocolDescriptorOffsetAddress.applyRelativeOffset(
+                protocolDescriptorOffsetValue);
 
         auto nameReader =
             QualifiedContextNameReader<ObjCInteropKind, PointerSize>(
@@ -2210,7 +2265,7 @@ class TypeRefBuilder {
     /// Extract conforming type's name from a Conformance Descriptor
     /// Returns a pair of (mangledTypeName, fullyQualifiedTypeName)
     std::optional<std::pair<std::string, std::string>> getConformingTypeName(
-        const uintptr_t conformanceDescriptorAddress,
+        const remote::RemoteAddress conformanceDescriptorAddress,
         const ExternalProtocolConformanceDescriptor<
             ObjCInteropKind, PointerSize> &conformanceDescriptor) {
       std::string typeName;
@@ -2232,12 +2287,11 @@ class TypeRefBuilder {
       //    descriptor
       //    - Address of the type descriptor is found at the (2) offset from the
       //      conformance descriptor address
-      auto contextDescriptorFieldAddress = detail::applyRelativeOffset(
-          (const char *)conformanceDescriptorAddress,
-          (int32_t)conformanceDescriptor.getTypeRefDescriptorOffset());
+      auto contextDescriptorFieldAddress =
+          conformanceDescriptorAddress.applyRelativeOffset(
+              (int32_t)conformanceDescriptor.getTypeRefDescriptorOffset());
       auto contextDescriptorOffsetBytes =
-          OpaqueByteReader(remote::RemoteAddress(contextDescriptorFieldAddress),
-                           sizeof(uint32_t));
+          OpaqueByteReader(contextDescriptorFieldAddress, sizeof(uint32_t));
       if (!contextDescriptorOffsetBytes.get()) {
         Error =
             "Failed to read type descriptor field in conformance descriptor.";
@@ -2247,15 +2301,15 @@ class TypeRefBuilder {
           (const int32_t *)contextDescriptorOffsetBytes.get();
 
       // Read the type descriptor itself using the address computed above
-      auto contextTypeDescriptorAddress = detail::applyRelativeOffset(
-          (const char *)contextDescriptorFieldAddress,
-          *contextDescriptorOffset);
+      auto contextTypeDescriptorAddress =
+          contextDescriptorFieldAddress.applyRelativeOffset(
+              *contextDescriptorOffset);
 
       // Instead of a type descriptor this may just be a reference to an
       // external, check that first
-      if (auto symbol = OpaqueDynamicSymbolResolver(
-              remote::RemoteAddress(contextTypeDescriptorAddress))) {
-        if (!symbol->isResolved()) {
+      if (auto symbol =
+              OpaqueDynamicSymbolResolver(contextTypeDescriptorAddress)) {
+        if (!symbol->getSymbol().empty() && symbol->getOffset() == 0) {
           Demangle::Context Ctx;
           auto demangledRoot =
               Ctx.demangleSymbolAsNode(symbol->getSymbol().str());
@@ -2274,10 +2328,10 @@ class TypeRefBuilder {
             mangledTypeName = typeMangling.result();
 
           return std::make_pair(mangledTypeName, typeName);
-        } else if (symbol->getOffset()) {
+        } else if (symbol->getResolvedAddress()) {
           // If symbol is empty and has an offset, this is the resolved remote
           // address
-          contextTypeDescriptorAddress = symbol->getOffset();
+          contextTypeDescriptorAddress = symbol->getResolvedAddress();
         }
       }
 
@@ -2291,17 +2345,17 @@ class TypeRefBuilder {
 
     /// Extract protocol name from a Conformance Descriptor
     std::optional<std::string> getConformanceProtocolName(
-        const uintptr_t conformanceDescriptorAddress,
+        const remote::RemoteAddress conformanceDescriptorAddress,
         const ExternalProtocolConformanceDescriptor<
             ObjCInteropKind, PointerSize> &conformanceDescriptor) {
       std::optional<std::string> protocolName;
-      auto protocolDescriptorFieldAddress = detail::applyRelativeOffset(
-          (const char *)conformanceDescriptorAddress,
-          (int32_t)conformanceDescriptor.getProtocolDescriptorOffset());
+      auto protocolDescriptorFieldAddress =
+          conformanceDescriptorAddress.applyRelativeOffset(
+
+              (int32_t)conformanceDescriptor.getProtocolDescriptorOffset());
 
-      auto protocolDescriptorOffsetBytes = OpaqueByteReader(
-          remote::RemoteAddress(protocolDescriptorFieldAddress),
-          sizeof(uint32_t));
+      auto protocolDescriptorOffsetBytes =
+          OpaqueByteReader(protocolDescriptorFieldAddress, sizeof(uint32_t));
       if (!protocolDescriptorOffsetBytes.get()) {
         Error = "Error reading protocol descriptor field in conformance "
                 "descriptor.";
@@ -2310,9 +2364,9 @@ class TypeRefBuilder {
       auto protocolDescriptorOffset =
           (const uint32_t *)protocolDescriptorOffsetBytes.get();
 
-      auto protocolDescriptorTarget = detail::applyRelativeOffset(
-          (const char *)protocolDescriptorFieldAddress,
-          (int32_t)*protocolDescriptorOffset);
+      auto protocolDescriptorTarget =
+          protocolDescriptorFieldAddress.applyRelativeOffset(
+              (int32_t)*protocolDescriptorOffset);
 
       return NameReader.readFullyQualifiedProtocolName(
           protocolDescriptorTarget);
@@ -2329,11 +2383,11 @@ class TypeRefBuilder {
                *)conformanceRecordRef.getLocalBuffer();
       // Read the Protocol Conformance Descriptor by getting its address from
       // the conformance record.
-      auto conformanceDescriptorAddress = (uintptr_t)CD->getRelative(
-          (void *)conformanceRecordRef.getAddressData());
+      auto conformanceDescriptorAddress =
+          conformanceRecordRef.getRemoteAddress().getRelative(CD);
 
       auto descriptorBytes = OpaqueByteReader(
-          remote::RemoteAddress(conformanceDescriptorAddress),
+          conformanceDescriptorAddress,
           sizeof(ExternalProtocolConformanceDescriptor<ObjCInteropKind,
                                                        PointerSize>));
       if (!descriptorBytes.get()) {
diff --git a/include/swift/RemoteInspection/TypeRefs.def b/include/swift/RemoteInspection/TypeRefs.def
index e3174bb620350..0fcd992999741 100644
--- a/include/swift/RemoteInspection/TypeRefs.def
+++ b/include/swift/RemoteInspection/TypeRefs.def
@@ -23,6 +23,7 @@ TYPEREF(Tuple, TypeRef)
 TYPEREF(Function, TypeRef)
 TYPEREF(ProtocolComposition, TypeRef)
 TYPEREF(ConstrainedExistential, TypeRef)
+TYPEREF(SymbolicExtendedExistential, TypeRef)
 TYPEREF(Metatype, TypeRef)
 TYPEREF(ExistentialMetatype, TypeRef)
 TYPEREF(GenericTypeParameter, TypeRef)
@@ -39,5 +40,7 @@ TYPEREF(SILBox, TypeRef)
 TYPEREF(SILBoxTypeWithLayout, TypeRef)
 TYPEREF(Integer, TypeRef)
 TYPEREF(BuiltinFixedArray, TypeRef)
+TYPEREF(Pack, TypeRef)
+TYPEREF(PackExpansion, TypeRef)
 
 #undef TYPEREF
diff --git a/include/swift/Runtime/CMakeConfig.h.in b/include/swift/Runtime/CMakeConfig.h.in
index 14d141525659c..187cad3074387 100644
--- a/include/swift/Runtime/CMakeConfig.h.in
+++ b/include/swift/Runtime/CMakeConfig.h.in
@@ -4,9 +4,6 @@
 #ifndef SWIFT_RUNTIME_CMAKECONFIG_H
 #define SWIFT_RUNTIME_CMAKECONFIG_H
 
-#cmakedefine01 SWIFT_BNI_OS_BUILD
-#cmakedefine01 SWIFT_BNI_XCODE_BUILD
-
 #define SWIFT_VERSION_MAJOR "@SWIFT_VERSION_MAJOR@"
 #define SWIFT_VERSION_MINOR "@SWIFT_VERSION_MINOR@"
 
diff --git a/include/swift/Runtime/CMakeLists.txt b/include/swift/Runtime/CMakeLists.txt
index 4646a7f738305..9d2b2e907e90c 100644
--- a/include/swift/Runtime/CMakeLists.txt
+++ b/include/swift/Runtime/CMakeLists.txt
@@ -1,14 +1,3 @@
-# Detect B&I builds.
-set(SWIFT_BNI_OS_BUILD FALSE)
-set(SWIFT_BNI_XCODE_BUILD FALSE)
-if(DEFINED ENV{RC_XBS})
-  if((NOT DEFINED ENV{RC_XCODE} OR NOT "$ENV{RC_XCODE}") AND (NOT DEFINED ENV{RC_PLAYGROUNDS} OR NOT "$ENV{RC_PLAYGROUNDS}"))
-    set(SWIFT_BNI_OS_BUILD TRUE)
-  else()
-    set(SWIFT_BNI_XCODE_BUILD TRUE)
-  endif()
-endif()
-
 configure_file(CMakeConfig.h.in ${CMAKE_CURRENT_BINARY_DIR}/CMakeConfig.h
                ESCAPE_QUOTES @ONLY)
 swift_install_in_component(FILES ${CMAKE_CURRENT_BINARY_DIR}/CMakeConfig.h
diff --git a/include/swift/Runtime/Concurrency.h b/include/swift/Runtime/Concurrency.h
index 57cddec85d946..69631393d0c02 100644
--- a/include/swift/Runtime/Concurrency.h
+++ b/include/swift/Runtime/Concurrency.h
@@ -45,17 +45,6 @@
 #define SWIFT_CONCURRENCY_ENABLE_DISPATCH 0
 #endif
 
-// Does the runtime provide priority escalation support?
-#ifndef SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION
-#if SWIFT_CONCURRENCY_ENABLE_DISPATCH && \
-    __has_include(<dispatch/swift_concurrency_private.h>) && __APPLE__ && \
-    (defined(__arm64__) || defined(__x86_64__))
-#define SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION 1
-#else
-#define SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION 0
-#endif
-#endif /* SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION */
-
 namespace swift {
 class DefaultActor;
 class TaskOptionRecord;
@@ -788,12 +777,12 @@ bool swift_task_invokeSwiftCheckIsolated(SerialExecutorRef executor);
 
 /// Invoke an executor's `isIsolatingCurrentContext` implementation;
 SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
-bool swift_task_isIsolatingCurrentContext(SerialExecutorRef executor);
+int8_t swift_task_isIsolatingCurrentContext(SerialExecutorRef executor);
 
 /// Invoke a Swift executor's `isIsolatingCurrentContext` implementation; returns
 /// `true` if it invoked the Swift implementation, `false` otherwise.
 SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
-bool swift_task_invokeSwiftIsIsolatingCurrentContext(SerialExecutorRef executor);
+int8_t swift_task_invokeSwiftIsIsolatingCurrentContext(SerialExecutorRef executor);
 
 /// A count in nanoseconds.
 using JobDelay = unsigned long long;
@@ -1052,12 +1041,6 @@ enum swift_task_is_current_executor_flag : uint64_t {
   /// The routine MUST NOT assert on failure.
   /// Even at the cost of not calling 'checkIsolated' if it is available.
   MustNotAssert = 0x10,
-
-  /// The routine should use 'isIsolatingCurrentContext' function on the
-  /// 'expected' executor instead of `checkIsolated`.
-  ///
-  /// This is a variant of `MustNotAssert`
-  UseIsIsolatingCurrentContext = 0x20,
 };
 
 SWIFT_EXPORT_FROM(swift_Concurrency)
@@ -1080,7 +1063,7 @@ SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
 void swift_task_startOnMainActor(AsyncTask* job);
 
 SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
-void swift_task_startSynchronously(AsyncTask* job);
+void swift_task_immediate(AsyncTask* job, SerialExecutorRef targetExecutor);
 
 /// Donate this thread to the global executor until either the
 /// given condition returns true or we've run out of cooperative
@@ -1091,7 +1074,8 @@ void swift_task_donateThreadToGlobalExecutorUntil(bool (*condition)(void*),
 
 enum swift_clock_id : int {
   swift_clock_id_continuous = 1,
-  swift_clock_id_suspending = 2
+  swift_clock_id_suspending = 2,
+  swift_clock_id_wall = 3
 };
 
 SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
diff --git a/include/swift/Runtime/ConcurrencyHooks.def b/include/swift/Runtime/ConcurrencyHooks.def
index 960753e4411ff..f087fd23e13e2 100644
--- a/include/swift/Runtime/ConcurrencyHooks.def
+++ b/include/swift/Runtime/ConcurrencyHooks.def
@@ -47,7 +47,7 @@ SWIFT_CONCURRENCY_HOOK(void, swift_task_enqueueGlobalWithDeadline,
 SWIFT_CONCURRENCY_HOOK(void, swift_task_checkIsolated,
     SerialExecutorRef executor);
 
-SWIFT_CONCURRENCY_HOOK(bool, swift_task_isIsolatingCurrentContext,
+SWIFT_CONCURRENCY_HOOK(int8_t, swift_task_isIsolatingCurrentContext,
     SerialExecutorRef executor);
 
 SWIFT_CONCURRENCY_HOOK(bool, swift_task_isOnExecutor,
diff --git a/include/swift/Runtime/Concurrent.h b/include/swift/Runtime/Concurrent.h
index c3a90415df6e5..e5134645544d3 100644
--- a/include/swift/Runtime/Concurrent.h
+++ b/include/swift/Runtime/Concurrent.h
@@ -593,6 +593,51 @@ struct ConcurrentReadableHashMap {
     }
   }
 
+  // Common implementation for `getOrInsert` and `GetOrInsertManyScope`
+  template <class KeyTy, typename Call>
+  void getOrInsertExternallyLocked(KeyTy key, const Call &call) {
+    auto indices = IndexStorage{Indices.load(std::memory_order_relaxed)};
+    auto indicesCapacityLog2 = indices.getCapacityLog2();
+    auto elementCount = ElementCount.load(std::memory_order_relaxed);
+    auto *elements = Elements.load(std::memory_order_relaxed);
+    auto *elementsPtr = elements ? elements->data() : nullptr;
+
+    
+    auto found = this->find(key, indices, elementCount, elementsPtr);
+    if (found.first) {
+      call(found.first, false);
+      return;
+    }
+
+    auto indicesCapacity = 1UL << indicesCapacityLog2;
+
+    // The number of slots in use is elementCount + 1, since the capacity also
+    // takes a slot.
+    auto emptyCount = indicesCapacity - (elementCount + 1);
+    auto proportion = indicesCapacity / emptyCount;
+    if (proportion >= ResizeProportion) {
+      indices = resize(indices, indicesCapacityLog2, elementsPtr);
+      found = find(key, indices, elementCount, elementsPtr);
+      assert(!found.first && "Shouldn't suddenly find the key after rehashing");
+    }
+
+    if (!elements || elementCount >= elements->Capacity) {
+      elements = resize(elements, elementCount);
+    }
+    auto *element = &elements->data()[elementCount];
+
+    // Order matters: fill out the element, then update the count,
+    // then update the index.
+    bool keep = call(element, true);
+    if (keep) {
+      assert(hash_value(key) == hash_value(*element) &&
+            "Element must have the same hash code as its key.");
+      ElementCount.store(elementCount + 1, std::memory_order_release);
+      indices.storeIndexAt(&Indices, elementCount + 1, found.second,
+                          std::memory_order_release);
+    }
+  }
+
 public:
   // Implicitly trivial constructor/destructor.
   ConcurrentReadableHashMap() = default;
@@ -684,6 +729,48 @@ struct ConcurrentReadableHashMap {
     return Snapshot(this, indices, elementsPtr, elementCount);
   }
 
+  /// A wrapper that allows performing several `getOrInsert` operations under
+  /// the same lock.
+  class GetOrInsertManyScope {
+    GetOrInsertManyScope() = delete;
+    GetOrInsertManyScope(const GetOrInsertManyScope &) = delete;
+    GetOrInsertManyScope &operator=(const GetOrInsertManyScope &) = delete;
+    GetOrInsertManyScope(GetOrInsertManyScope &&) = delete;
+    GetOrInsertManyScope &operator=(GetOrInsertManyScope &&) = delete;
+
+    ConcurrentReadableHashMap &Map;
+
+  public:
+    GetOrInsertManyScope(ConcurrentReadableHashMap &map) : Map(map) {
+      Map.WriterLock.lock();
+    }
+
+    ~GetOrInsertManyScope() {
+      Map.deallocateFreeListIfSafe();
+      Map.WriterLock.unlock();
+    }
+
+    /// Get an element by key, or insert a new element for that key if one is
+    /// not already present. Invoke `call` with the pointer to the element.
+    ///
+    /// `call` is passed the following parameters:
+    ///   - `element`: the pointer to the element corresponding to `key`
+    ///   - `created`: true if the element is newly created, false if it already
+    ///                exists
+    /// `call` returns a `bool`. When `created` is `true`, the return values
+    /// mean:
+    ///   - `true` the new entry is to be kept
+    ///   - `false` indicates that the new entry is discarded
+    /// If the new entry is kept, then the new element MUST be initialized, and
+    /// have a hash value that matches the hash value of `key`.
+    ///
+    /// The return value is ignored when `created` is `false`.
+    template <class KeyTy, typename Call>
+    void getOrInsert(KeyTy key, const Call &call) {
+      Map.getOrInsertExternallyLocked(key, call);
+    }
+  };
+
   /// Get an element by key, or insert a new element for that key if one is not
   /// already present. Invoke `call` with the pointer to the element. BEWARE:
   /// `call` is invoked with the internal writer lock held, keep work to a
@@ -703,54 +790,18 @@ struct ConcurrentReadableHashMap {
   template <class KeyTy, typename Call>
   void getOrInsert(KeyTy key, const Call &call) {
     typename MutexTy::ScopedLock guard(WriterLock);
-
-    auto indices = IndexStorage{Indices.load(std::memory_order_relaxed)};
-    auto indicesCapacityLog2 = indices.getCapacityLog2();
-    auto elementCount = ElementCount.load(std::memory_order_relaxed);
-    auto *elements = Elements.load(std::memory_order_relaxed);
-    auto *elementsPtr = elements ? elements->data() : nullptr;
-
-    auto found = this->find(key, indices, elementCount, elementsPtr);
-    if (found.first) {
-      call(found.first, false);
-      deallocateFreeListIfSafe();
-      return;
-    }
-
-    auto indicesCapacity = 1UL << indicesCapacityLog2;
-
-    // The number of slots in use is elementCount + 1, since the capacity also
-    // takes a slot.
-    auto emptyCount = indicesCapacity - (elementCount + 1);
-    auto proportion = indicesCapacity / emptyCount;
-    if (proportion >= ResizeProportion) {
-      indices = resize(indices, indicesCapacityLog2, elementsPtr);
-      found = find(key, indices, elementCount, elementsPtr);
-      assert(!found.first && "Shouldn't suddenly find the key after rehashing");
-    }
-
-    if (!elements || elementCount >= elements->Capacity) {
-      elements = resize(elements, elementCount);
-    }
-    auto *element = &elements->data()[elementCount];
-
-    // Order matters: fill out the element, then update the count,
-    // then update the index.
-    bool keep = call(element, true);
-    if (keep) {
-      assert(hash_value(key) == hash_value(*element) &&
-             "Element must have the same hash code as its key.");
-      ElementCount.store(elementCount + 1, std::memory_order_release);
-      indices.storeIndexAt(&Indices, elementCount + 1, found.second,
-                           std::memory_order_release);
-    }
-
+    getOrInsertExternallyLocked(key, call);
     deallocateFreeListIfSafe();
   }
 
   /// Clear the hash table, freeing (when safe) all memory currently used for
   /// indices and elements.
-  void clear() {
+  ///
+  /// - addFreedNodes: if nonempty, this function will be called with the head
+  /// of the free list. The function may add additional nodes to the free
+  /// list, which will be freed when it is safe to do so.
+  void clear(std::function<void(ConcurrentFreeListNode *&)> addFreedNodes
+                 = nullptr) {
     typename MutexTy::ScopedLock guard(WriterLock);
 
     IndexStorage indices = Indices.load(std::memory_order_relaxed);
@@ -766,6 +817,9 @@ struct ConcurrentReadableHashMap {
       ConcurrentFreeListNode::add(&FreeList, ptr);
     ConcurrentFreeListNode::add(&FreeList, elements);
 
+    if (addFreedNodes)
+      addFreedNodes(FreeList);
+
     deallocateFreeListIfSafe();
   }
 };
diff --git a/include/swift/Runtime/Config.h b/include/swift/Runtime/Config.h
index 2b50bf4429443..457cdacc8537d 100644
--- a/include/swift/Runtime/Config.h
+++ b/include/swift/Runtime/Config.h
@@ -272,6 +272,9 @@ extern uintptr_t __COMPATIBILITY_LIBRARIES_CANNOT_CHECK_THE_IS_SWIFT_BIT_DIRECTL
 #define __ptrauth_swift_type_descriptor \
   __ptrauth(ptrauth_key_process_independent_data, 1, \
             SpecialPointerAuthDiscriminators::TypeDescriptor)
+#define __ptrauth_swift_protocol_conformance_descriptor \
+  __ptrauth(ptrauth_key_process_independent_data, 1, \
+            SpecialPointerAuthDiscriminators::ProtocolConformanceDescriptor)
 #define __ptrauth_swift_dynamic_replacement_key                                \
   __ptrauth(ptrauth_key_process_independent_data, 1,                           \
             SpecialPointerAuthDiscriminators::DynamicReplacementKey)
@@ -365,6 +368,7 @@ extern uintptr_t __COMPATIBILITY_LIBRARIES_CANNOT_CHECK_THE_IS_SWIFT_BIT_DIRECTL
 #define __ptrauth_swift_runtime_function_entry_strip(__fn) (__fn)
 #define __ptrauth_swift_heap_object_destructor
 #define __ptrauth_swift_type_descriptor
+#define __ptrauth_swift_protocol_conformance_descriptor
 #define __ptrauth_swift_nonunique_extended_existential_type_shape
 #define __ptrauth_swift_dynamic_replacement_key
 #define swift_ptrauth_sign_opaque_read_resume_function(__fn, __buffer) (__fn)
@@ -550,17 +554,6 @@ swift_auth_code(T value, unsigned extra) {
 #endif
 }
 
-template <typename T>
-SWIFT_RUNTIME_ATTRIBUTE_ALWAYS_INLINE static inline T
-swift_auth_code_function(T value, unsigned extra) {
-#if SWIFT_PTRAUTH
-  return (T)ptrauth_auth_function((void *)value,
-                                  ptrauth_key_function_pointer, extra);
-#else
-  return value;
-#endif
-}
-
 /// Does this platform support backtrace-on-crash?
 #ifdef __APPLE__
 #  include <TargetConditionals.h>
diff --git a/include/swift/Runtime/Debug.h b/include/swift/Runtime/Debug.h
index 9e7a7e7afac7c..59ed6c886a37c 100644
--- a/include/swift/Runtime/Debug.h
+++ b/include/swift/Runtime/Debug.h
@@ -266,6 +266,14 @@ bool _swift_debug_metadataAllocationIterationEnabled;
 SWIFT_RUNTIME_STDLIB_SPI
 const void * const _swift_debug_allocationPoolPointer;
 
+SWIFT_RUNTIME_STDLIB_SPI
+const size_t _swift_debug_allocationPoolSize;
+
+// The size of the pages the metadata allocator allocates on the heap. May be
+// used to filter out possible metadata pages when examining the heap.
+SWIFT_RUNTIME_STDLIB_SPI
+const size_t _swift_debug_metadataAllocatorPageSize;
+
 SWIFT_RUNTIME_STDLIB_SPI
 std::atomic<const void *> _swift_debug_metadataAllocationBacktraceList;
 
diff --git a/include/swift/Runtime/HeapObject.h b/include/swift/Runtime/HeapObject.h
index 0dd83eabc2445..276565dc2b01e 100644
--- a/include/swift/Runtime/HeapObject.h
+++ b/include/swift/Runtime/HeapObject.h
@@ -1159,8 +1159,7 @@ swift_getMangledTypeName(const Metadata *type);
 #define STANDARD_OBJC_METHOD_IMPLS_FOR_SWIFT_OBJECTS \
 - (id)retain { \
   auto SELF = reinterpret_cast<HeapObject *>(self); \
-  swift_retain(SELF); \
-  return self; \
+  return reinterpret_cast<id>(swift_retain(SELF)); \
 } \
 - (oneway void)release { \
   auto SELF = reinterpret_cast<HeapObject *>(self); \
diff --git a/include/swift/Runtime/RuntimeFunctions.def b/include/swift/Runtime/RuntimeFunctions.def
index 97d7f2c9299b3..7709fc11dac54 100644
--- a/include/swift/Runtime/RuntimeFunctions.def
+++ b/include/swift/Runtime/RuntimeFunctions.def
@@ -175,7 +175,7 @@ FUNCTION(SlowDealloc, Swift, swift_slowDealloc, C_CC, AlwaysAvailable,
 // void swift_willThrow(error *ptr);
 FUNCTION(WillThrow, Swift, swift_willThrow, SwiftCC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(Int8PtrTy, ErrorPtrTy->getPointerTo()),
+         ARGS(Int8PtrTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::NoEffect),
          UNKNOWN_MEMEFFECTS)
@@ -759,10 +759,7 @@ FUNCTION(ArrayDestroy, Swift, swift_arrayDestroy, C_CC, AlwaysAvailable,
 FUNCTION(GetFunctionMetadata, Swift, swift_getFunctionTypeMetadata,
          C_CC, AlwaysAvailable,
          RETURNS(TypeMetadataPtrTy),
-         ARGS(SizeTy,
-              TypeMetadataPtrTy->getPointerTo(0),
-              Int32Ty->getPointerTo(0),
-              TypeMetadataPtrTy),
+         ARGS(SizeTy, PtrTy, PtrTy, TypeMetadataPtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          MEMEFFECTS(ReadOnly))
@@ -777,11 +774,7 @@ FUNCTION(GetFunctionMetadataDifferentiable,
          Swift, swift_getFunctionTypeMetadataDifferentiable,
          C_CC, AlwaysAvailable,
          RETURNS(TypeMetadataPtrTy),
-         ARGS(SizeTy,
-              SizeTy,
-              TypeMetadataPtrTy->getPointerTo(0),
-              Int32Ty->getPointerTo(0),
-              TypeMetadataPtrTy),
+         ARGS(SizeTy, SizeTy, PtrTy, PtrTy, TypeMetadataPtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          MEMEFFECTS(ReadOnly))
@@ -801,8 +794,8 @@ FUNCTION(GetFunctionMetadataExtended,
          RETURNS(TypeMetadataPtrTy),
          ARGS(SizeTy,
               SizeTy,
-              TypeMetadataPtrTy->getPointerTo(0),
-              Int32Ty->getPointerTo(0),
+              PtrTy,
+              PtrTy,
               TypeMetadataPtrTy,
               TypeMetadataPtrTy,
               Int32Ty,
@@ -824,8 +817,8 @@ FUNCTION(GetFunctionMetadataGlobalActor,
          RETURNS(TypeMetadataPtrTy),
          ARGS(SizeTy,
               SizeTy,
-              TypeMetadataPtrTy->getPointerTo(0),
-              Int32Ty->getPointerTo(0),
+              PtrTy,
+              PtrTy,
               TypeMetadataPtrTy,
               TypeMetadataPtrTy),
          ATTRS(NoUnwind),
@@ -845,8 +838,8 @@ FUNCTION(GetFunctionMetadataGlobalActorBackDeploy,
          RETURNS(TypeMetadataPtrTy),
          ARGS(SizeTy,
               SizeTy,
-              TypeMetadataPtrTy->getPointerTo(0),
-              Int32Ty->getPointerTo(0),
+              PtrTy,
+              PtrTy,
               TypeMetadataPtrTy,
               TypeMetadataPtrTy),
          ATTRS(NoUnwind),
@@ -963,7 +956,7 @@ FUNCTION(GetCanonicalPrespecializedGenericMetadata,
          Swift, swift_getCanonicalPrespecializedGenericMetadata,
          SwiftCC, GetCanonicalPrespecializedGenericMetadataAvailability,
          RETURNS(TypeMetadataResponseTy),
-         ARGS(SizeTy, Int8PtrTy, TypeContextDescriptorPtrTy, OnceTy->getPointerTo()),
+         ARGS(SizeTy, Int8PtrTy, TypeContextDescriptorPtrTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          MEMEFFECTS(ReadOnly))
@@ -1108,22 +1101,14 @@ FUNCTION(GetWitnessTableRelative, Swift, swift_getWitnessTableRelative, C_CC, Al
 FUNCTION(GetAssociatedTypeWitness, Swift, swift_getAssociatedTypeWitness,
          SwiftCC, AlwaysAvailable,
          RETURNS(TypeMetadataResponseTy),
-         ARGS(SizeTy,
-              WitnessTablePtrTy,
-              TypeMetadataPtrTy,
-              ProtocolRequirementStructTy->getPointerTo(),
-              ProtocolRequirementStructTy->getPointerTo()),
+         ARGS(SizeTy, WitnessTablePtrTy, TypeMetadataPtrTy, PtrTy, PtrTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::MetaData), // ?
          MEMEFFECTS(ReadNone))
 FUNCTION(GetAssociatedTypeWitnessRelative, Swift, swift_getAssociatedTypeWitnessRelative,
          SwiftCC, AlwaysAvailable,
          RETURNS(TypeMetadataResponseTy),
-         ARGS(SizeTy,
-              WitnessTablePtrTy,
-              TypeMetadataPtrTy,
-              ProtocolRequirementStructTy->getPointerTo(),
-              ProtocolRequirementStructTy->getPointerTo()),
+         ARGS(SizeTy, WitnessTablePtrTy, TypeMetadataPtrTy, PtrTy, PtrTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::MetaData), // ?
          MEMEFFECTS(ReadNone))
@@ -1141,8 +1126,8 @@ FUNCTION(GetAssociatedConformanceWitness,
          ARGS(WitnessTablePtrTy,
               TypeMetadataPtrTy,
               TypeMetadataPtrTy,
-              ProtocolRequirementStructTy->getPointerTo(),
-              ProtocolRequirementStructTy->getPointerTo()),
+              PtrTy,
+              PtrTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::MetaData), // ?
          MEMEFFECTS(ReadNone))
@@ -1152,8 +1137,8 @@ FUNCTION(GetAssociatedConformanceWitnessRelative,
          ARGS(WitnessTablePtrTy,
               TypeMetadataPtrTy,
               TypeMetadataPtrTy,
-              ProtocolRequirementStructTy->getPointerTo(),
-              ProtocolRequirementStructTy->getPointerTo()),
+              PtrTy,
+              PtrTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::MetaData), // ?
          MEMEFFECTS(ReadNone))
@@ -1248,8 +1233,7 @@ FUNCTION(GetObjCClassFromObject, Swift, swift_getObjCClassFromObject,
 //                                             value_witness_table_t *proposed);
 FUNCTION(GetTupleMetadata, Swift, swift_getTupleTypeMetadata, SwiftCC, AlwaysAvailable,
          RETURNS(TypeMetadataResponseTy),
-         ARGS(SizeTy, SizeTy, TypeMetadataPtrTy->getPointerTo(0),
-              Int8PtrTy, WitnessTablePtrTy),
+         ARGS(SizeTy, SizeTy, PtrTy, Int8PtrTy, WitnessTablePtrTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::MetaData),
          MEMEFFECTS(ReadOnly))
@@ -1285,8 +1269,7 @@ FUNCTION(GetTupleMetadata3, Swift, swift_getTupleTypeMetadata3, SwiftCC, AlwaysA
 //                               const TypeLayout * const *elts);
 FUNCTION(GetTupleLayout, Swift, swift_getTupleTypeLayout, SwiftCC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(FullTypeLayoutTy->getPointerTo(0), Int32Ty->getPointerTo(0),
-              SizeTy, Int8PtrPtrTy->getPointerTo(0)),
+         ARGS(PtrTy, PtrTy, SizeTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::NoEffect),
          UNKNOWN_MEMEFFECTS)
@@ -1296,7 +1279,7 @@ FUNCTION(GetTupleLayout, Swift, swift_getTupleTypeLayout, SwiftCC, AlwaysAvailab
 //                                  const TypeLayout *elt1);
 FUNCTION(GetTupleLayout2, Swift, swift_getTupleTypeLayout2, SwiftCC, AlwaysAvailable,
          RETURNS(SizeTy),
-         ARGS(FullTypeLayoutTy->getPointerTo(0), Int8PtrPtrTy, Int8PtrPtrTy),
+         ARGS(PtrTy, Int8PtrPtrTy, Int8PtrPtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::NoEffect),
          UNKNOWN_MEMEFFECTS)
@@ -1307,8 +1290,7 @@ FUNCTION(GetTupleLayout2, Swift, swift_getTupleTypeLayout2, SwiftCC, AlwaysAvail
 //                                      const TypeLayout *elt2);
 FUNCTION(GetTupleLayout3, Swift, swift_getTupleTypeLayout3, SwiftCC, AlwaysAvailable,
          RETURNS(OffsetPairTy),
-         ARGS(FullTypeLayoutTy->getPointerTo(0),
-              Int8PtrPtrTy, Int8PtrPtrTy, Int8PtrPtrTy),
+         ARGS(PtrTy, Int8PtrPtrTy, Int8PtrPtrTy, Int8PtrPtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::NoEffect),
          UNKNOWN_MEMEFFECTS)
@@ -1335,8 +1317,7 @@ FUNCTION(GetExistentialMetadata,
          Swift, swift_getExistentialTypeMetadata,
          C_CC, AlwaysAvailable,
          RETURNS(TypeMetadataPtrTy),
-         ARGS(Int1Ty, TypeMetadataPtrTy, SizeTy,
-              ProtocolDescriptorRefTy->getPointerTo()),
+         ARGS(Int1Ty, TypeMetadataPtrTy, SizeTy, PtrTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::MetaData), // ?
          MEMEFFECTS(ReadOnly))
@@ -1396,9 +1377,7 @@ FUNCTION(RelocateClassMetadata,
 FUNCTION(InitClassMetadata,
          Swift, swift_initClassMetadata, C_CC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy,
-              Int8PtrPtrTy->getPointerTo(),
-              SizeTy->getPointerTo()),
+         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy, PtrTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          UNKNOWN_MEMEFFECTS)
@@ -1411,9 +1390,7 @@ FUNCTION(InitClassMetadata,
 FUNCTION(UpdateClassMetadata,
          Swift, swift_updateClassMetadata, C_CC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy,
-              Int8PtrPtrTy->getPointerTo(),
-              SizeTy->getPointerTo()),
+         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy, PtrTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          UNKNOWN_MEMEFFECTS)
@@ -1426,9 +1403,7 @@ FUNCTION(UpdateClassMetadata,
 FUNCTION(InitClassMetadata2,
          Swift, swift_initClassMetadata2, SwiftCC, AlwaysAvailable,
          RETURNS(TypeMetadataDependencyTy),
-         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy,
-              Int8PtrPtrTy->getPointerTo(),
-              SizeTy->getPointerTo()),
+         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy, PtrTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          UNKNOWN_MEMEFFECTS)
@@ -1441,9 +1416,7 @@ FUNCTION(InitClassMetadata2,
 FUNCTION(UpdateClassMetadata2,
          Swift, swift_updateClassMetadata2, SwiftCC, AlwaysAvailable,
          RETURNS(TypeMetadataDependencyTy),
-         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy,
-              Int8PtrPtrTy->getPointerTo(),
-              SizeTy->getPointerTo()),
+         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy, PtrTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          UNKNOWN_MEMEFFECTS)
@@ -1456,7 +1429,7 @@ FUNCTION(UpdateClassMetadata2,
 FUNCTION(UpdatePureObjCClassMetadata,
          Swift, swift_updatePureObjCClassMetadata, SwiftCC, AlwaysAvailable,
          RETURNS(ObjCClassPtrTy),
-         ARGS(ObjCClassPtrTy, SizeTy, SizeTy, Int8PtrPtrTy->getPointerTo()),
+         ARGS(ObjCClassPtrTy, SizeTy, SizeTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          UNKNOWN_MEMEFFECTS)
@@ -1467,9 +1440,7 @@ FUNCTION(UpdatePureObjCClassMetadata,
 FUNCTION(LookUpClassMethod,
          Swift, swift_lookUpClassMethod, C_CC, AlwaysAvailable,
          RETURNS(Int8PtrTy),
-         ARGS(TypeMetadataPtrTy,
-              MethodDescriptorStructTy->getPointerTo(),
-              TypeContextDescriptorPtrTy),
+         ARGS(TypeMetadataPtrTy, PtrTy, TypeContextDescriptorPtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::NoEffect),
          UNKNOWN_MEMEFFECTS)
@@ -1482,9 +1453,7 @@ FUNCTION(LookUpClassMethod,
 FUNCTION(InitStructMetadata,
          Swift, swift_initStructMetadata, C_CC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy,
-              Int8PtrPtrTy->getPointerTo(0),
-              Int32Ty->getPointerTo()),
+         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy, PtrTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          UNKNOWN_MEMEFFECTS)
@@ -1498,10 +1467,7 @@ FUNCTION(InitStructMetadata,
 FUNCTION(InitStructMetadataWithLayoutString,
          Swift, swift_cvw_initStructMetadataWithLayoutString, C_CC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy,
-              Int8PtrPtrTy->getPointerTo(0),
-              Int8PtrTy,
-              Int32Ty->getPointerTo()),
+         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy, PtrTy, Int8PtrTy, PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          UNKNOWN_MEMEFFECTS)
@@ -1564,7 +1530,7 @@ FUNCTION(InitEnumMetadataMultiPayload,
          Swift, swift_initEnumMetadataMultiPayload,
          C_CC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy, Int8PtrPtrTy->getPointerTo(0)),
+         ARGS(TypeMetadataPtrTy, SizeTy, SizeTy, PtrTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::MetaData),
          UNKNOWN_MEMEFFECTS)
@@ -1603,10 +1569,7 @@ FUNCTION(GetEnumTagSinglePayloadGeneric,
          Swift, swift_getEnumTagSinglePayloadGeneric,
          SwiftCC, AlwaysAvailable,
          RETURNS(Int32Ty),
-         ARGS(OpaquePtrTy, Int32Ty, TypeMetadataPtrTy,
-              llvm::FunctionType::get(Int32Ty, {OpaquePtrTy, Int32Ty,
-                                                TypeMetadataPtrTy},
-                                      false)->getPointerTo()),
+         ARGS(OpaquePtrTy, Int32Ty, TypeMetadataPtrTy, PtrTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::NoEffect),
          MEMEFFECTS(ReadOnly))
@@ -1624,10 +1587,7 @@ FUNCTION(StoreEnumTagSinglePayloadGeneric,
          Swift, swift_storeEnumTagSinglePayloadGeneric,
          SwiftCC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(OpaquePtrTy, Int32Ty, Int32Ty, TypeMetadataPtrTy,
-              llvm::FunctionType::get(VoidTy, {OpaquePtrTy, Int32Ty, Int32Ty,
-                                               TypeMetadataPtrTy},
-                                      false)->getPointerTo()),
+         ARGS(OpaquePtrTy, Int32Ty, Int32Ty, TypeMetadataPtrTy, PtrTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::NoEffect),
          UNKNOWN_MEMEFFECTS)
@@ -1901,7 +1861,7 @@ FUNCTION(IsOptionalType,
 //                 void *context);
 FUNCTION(Once, Swift, swift_once, C_CC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(OnceTy->getPointerTo(), Int8PtrTy, Int8PtrTy),
+         ARGS(PtrTy, Int8PtrTy, Int8PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::Locking),
          UNKNOWN_MEMEFFECTS)
@@ -1936,7 +1896,7 @@ FUNCTION(RegisterTypeMetadataRecords,
 // void swift_beginAccess(void *pointer, ValueBuffer *scratch, size_t flags);
 FUNCTION(BeginAccess, Swift, swift_beginAccess, C_CC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(Int8PtrTy, getFixedBufferTy()->getPointerTo(), SizeTy, Int8PtrTy),
+         ARGS(Int8PtrTy, PtrTy, SizeTy, Int8PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::ExclusivityChecking),
          UNKNOWN_MEMEFFECTS)
@@ -1944,7 +1904,7 @@ FUNCTION(BeginAccess, Swift, swift_beginAccess, C_CC, AlwaysAvailable,
 // void swift_endAccess(ValueBuffer *scratch);
 FUNCTION(EndAccess, Swift, swift_endAccess, C_CC, AlwaysAvailable,
          RETURNS(VoidTy),
-         ARGS(getFixedBufferTy()->getPointerTo()),
+         ARGS(PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::ExclusivityChecking),
          UNKNOWN_MEMEFFECTS)
@@ -1952,7 +1912,7 @@ FUNCTION(EndAccess, Swift, swift_endAccess, C_CC, AlwaysAvailable,
 FUNCTION(GetOrigOfReplaceable, Swift, swift_getOrigOfReplaceable, C_CC,
          DynamicReplacementAvailability,
          RETURNS(FunctionPtrTy),
-         ARGS(FunctionPtrTy->getPointerTo()),
+         ARGS(PtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::NoEffect),
          UNKNOWN_MEMEFFECTS)
@@ -1960,7 +1920,7 @@ FUNCTION(GetOrigOfReplaceable, Swift, swift_getOrigOfReplaceable, C_CC,
 FUNCTION(GetReplacement, Swift, swift_getFunctionReplacement, C_CC,
          DynamicReplacementAvailability,
          RETURNS(FunctionPtrTy),
-         ARGS(FunctionPtrTy->getPointerTo(), FunctionPtrTy),
+         ARGS(PtrTy, FunctionPtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::NoEffect),
          UNKNOWN_MEMEFFECTS)
@@ -2099,12 +2059,19 @@ FUNCTION(Free, c, free, C_CC, AlwaysAvailable,
          NO_ATTRS,
          EFFECT(RuntimeEffect::Deallocating),
          UNKNOWN_MEMEFFECTS)
-FUNCTION(CoroFrameAlloc, Swift, swift_coroFrameAlloc, C_CC, AlwaysAvailable,
+FUNCTION(CoroFrameAlloc, Swift, swift_coroFrameAlloc, C_CC,
+         TypedCoroAllocAvailability,
          RETURNS(Int8PtrTy),
          ARGS(SizeTy, Int64Ty),
          NO_ATTRS,
          EFFECT(RuntimeEffect::Allocating),
          UNKNOWN_MEMEFFECTS)
+FUNCTION(coroFrameAllocStub, Swift, swift_coroFrameAllocStub, C_CC,
+         AlwaysAvailable, RETURNS(Int8PtrTy),
+         ARGS(SizeTy, Int64Ty),
+         ATTRS(NoUnwind),
+         EFFECT(RuntimeEffect::Allocating),
+         UNKNOWN_MEMEFFECTS)
 
 // void *_Block_copy(void *block);
 FUNCTION(BlockCopy, BlocksRuntime, _Block_copy, C_CC, AlwaysAvailable,
@@ -2234,14 +2201,14 @@ FUNCTION(VerifyTypeLayoutAttribute, Swift, _swift_debug_verifyTypeLayoutAttribut
 // float swift_intToFloat32(const size_t *data, IntegerLiteralFlags flags);
 FUNCTION(IntToFloat32, Swift, swift_intToFloat32, SwiftCC, AlwaysAvailable,
          RETURNS(FloatTy),
-         ARGS(SizeTy->getPointerTo(), SizeTy),
+         ARGS(PtrTy, SizeTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::NoEffect),
          MEMEFFECTS(ReadOnly))
 
 FUNCTION(IntToFloat64, Swift, swift_intToFloat64, SwiftCC, AlwaysAvailable,
          RETURNS(DoubleTy),
-         ARGS(SizeTy->getPointerTo(), SizeTy),
+         ARGS(PtrTy, SizeTy),
          ATTRS(NoUnwind, WillReturn),
          EFFECT(RuntimeEffect::NoEffect),
          MEMEFFECTS(ReadOnly))
@@ -2370,7 +2337,7 @@ FUNCTION(TaskCreate,
               RefCountedPtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::Concurrency),
-         MEMEFFECTS(ArgMemOnly))
+         MEMEFFECTS(ReadOnly))
 
 // void swift_task_switch(AsyncContext *resumeContext,
 //                        TaskContinuationFunction *resumeFunction,
@@ -2390,13 +2357,25 @@ FUNCTION(TaskSwitchFunc,
 //                                  size_t flags);
 FUNCTION(DeinitOnExecutorFunc,
          _Concurrency, swift_task_deinitOnExecutor, SwiftCC,
-         ConcurrencyAvailability,
+         IsolatedDeinitAvailability,
          RETURNS(VoidTy),
          ARGS(Int8PtrTy, Int8PtrTy, ExecutorFirstTy, ExecutorSecondTy, SizeTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::Concurrency),
          UNKNOWN_MEMEFFECTS)
 
+// void swift_task_deinitOnExecutorMainActorBackDeploy(void *object,
+//                                  DeinitWorkFunction *work,
+//                                  SerialExecutorRef newExecutor,
+//                                  size_t flags);
+FUNCTION(DeinitOnExecutorMainActorBackDeployFunc,
+         _Concurrency, deinitOnExecutorMainActorBackDeploy, SwiftCC,
+         ConcurrencyAvailability,
+         RETURNS(VoidTy),
+         ARGS(Int8PtrTy, Int8PtrTy, ExecutorFirstTy, ExecutorSecondTy, SizeTy),
+         ATTRS(NoUnwind),
+         EFFECT(RuntimeEffect::Concurrency),
+         UNKNOWN_MEMEFFECTS)
 
 // AsyncTask *swift_continuation_init(AsyncContext *continuationContext,
 //                                    AsyncContinuationFlags);
@@ -2765,9 +2744,7 @@ FUNCTION(GenericInitializeBufferWithCopyOfBuffer,
          Swift, swift_cvw_initializeBufferWithCopyOfBuffer,
          C_CC, AlwaysAvailable,
          RETURNS(Int8PtrTy),
-         ARGS(getFixedBufferTy()->getPointerTo(),
-              getFixedBufferTy()->getPointerTo(),
-              TypeMetadataPtrTy),
+         ARGS(PtrTy, PtrTy, TypeMetadataPtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::RefCounting),
          UNKNOWN_MEMEFFECTS)
@@ -2827,9 +2804,7 @@ FUNCTION(GenericInitializeBufferWithCopyOfBufferMultiPayloadEnumFN,
          Swift, swift_cvw_initializeBufferWithCopyOfBufferMultiPayloadEnumFN,
          C_CC, AlwaysAvailable,
          RETURNS(Int8PtrTy),
-         ARGS(getFixedBufferTy()->getPointerTo(),
-              getFixedBufferTy()->getPointerTo(),
-              TypeMetadataPtrTy),
+         ARGS(PtrTy, PtrTy, TypeMetadataPtrTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::RefCounting),
          UNKNOWN_MEMEFFECTS)
@@ -2956,7 +2931,7 @@ FUNCTION(InitRawStructMetadata,
          Swift, swift_initRawStructMetadata,
          C_CC, InitRawStructMetadataAvailability,
          RETURNS(VoidTy),
-         ARGS(TypeMetadataPtrTy, SizeTy, Int8PtrPtrTy->getPointerTo(0), Int32Ty),
+         ARGS(TypeMetadataPtrTy, SizeTy, PtrTy, Int32Ty),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
          UNKNOWN_MEMEFFECTS)
@@ -2970,7 +2945,7 @@ FUNCTION(InitRawStructMetadata2,
          Swift, swift_initRawStructMetadata2,
          C_CC, InitRawStructMetadata2Availability,
          RETURNS(VoidTy),
-         ARGS(TypeMetadataPtrTy, SizeTy, Int8PtrPtrTy->getPointerTo(0), SizeTy,
+         ARGS(TypeMetadataPtrTy, SizeTy, PtrTy, SizeTy,
               SizeTy),
          ATTRS(NoUnwind),
          EFFECT(RuntimeEffect::MetaData),
diff --git a/include/swift/Runtime/STLCompatibility.h b/include/swift/Runtime/STLCompatibility.h
deleted file mode 100644
index e2c5aa27cff18..0000000000000
--- a/include/swift/Runtime/STLCompatibility.h
+++ /dev/null
@@ -1,45 +0,0 @@
-//===---- STLCompatibility.h - Runtime C++ Compatibiltiy Stubs --*- C++ -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef SWIFT_RUNTIME_STL_COMPATIBILITY_H
-#define SWIFT_RUNTIME_STL_COMPATIBILITY_H
-
-#if __cplusplus >= 202002l || defined(__cpp_lib_bit_cast)
-#include <bit>
-#else
-#include <cstdint>
-#include <cstring>
-#include <memory>
-#include <type_traits>
-
-namespace std {
-inline namespace __swift {
-template <typename Destination, typename Source>
-std::enable_if_t<sizeof(Destination) == sizeof(Source) &&
-                 std::is_trivially_copyable_v<Source> &&
-                 std::is_trivially_copyable_v<Destination>, Destination>
-bit_cast(const Source &src) noexcept {
-  static_assert(std::is_trivially_constructible_v<Destination>,
-                "The destination type must be trivially constructible");
-  Destination dst;
-  if constexpr (std::is_pointer_v<Source> || std::is_pointer_v<Destination>)
-    std::memcpy(reinterpret_cast<uintptr_t *>(&dst),
-                reinterpret_cast<const uintptr_t *>(&src), sizeof(Destination));
-  else
-    std::memcpy(&dst, &src, sizeof(Destination));
-  return dst;
-}
-}
-}
-#endif
-
-#endif
diff --git a/include/swift/SIL/AddressWalker.h b/include/swift/SIL/AddressWalker.h
index cbfb50bf65f04..2b680b69c7038 100644
--- a/include/swift/SIL/AddressWalker.h
+++ b/include/swift/SIL/AddressWalker.h
@@ -214,8 +214,7 @@ TransitiveAddressWalker<Impl>::walk(SILValue projectedAddress) {
         isa<AssignInst>(user) || isa<LoadUnownedInst>(user) ||
         isa<StoreUnownedInst>(user) || isa<EndApplyInst>(user) ||
         isa<LoadWeakInst>(user) || isa<StoreWeakInst>(user) ||
-        isa<AssignByWrapperInst>(user) || isa<AssignOrInitInst>(user) ||
-        isa<BeginUnpairedAccessInst>(user) ||
+        isa<AssignOrInitInst>(user) || isa<BeginUnpairedAccessInst>(user) ||
         isa<EndUnpairedAccessInst>(user) || isa<WitnessMethodInst>(user) ||
         isa<SelectEnumAddrInst>(user) || isa<InjectEnumAddrInst>(user) ||
         isa<IsUniqueInst>(user) || isa<ValueMetatypeInst>(user) ||
@@ -229,7 +228,8 @@ TransitiveAddressWalker<Impl>::walk(SILValue projectedAddress) {
         isa<PackElementSetInst>(user) || isa<PackElementGetInst>(user) ||
         isa<DeinitExistentialAddrInst>(user) || isa<LoadBorrowInst>(user) ||
         isa<TupleAddrConstructorInst>(user) || isa<DeallocPackInst>(user) ||
-        isa<MergeIsolationRegionInst>(user)) {
+        isa<MergeIsolationRegionInst>(user) ||
+        isa<EndCOWMutationAddrInst>(user)) {
       callVisitUse(op);
       continue;
     }
@@ -249,6 +249,7 @@ TransitiveAddressWalker<Impl>::walk(SILValue projectedAddress) {
         isa<BeginAccessInst>(user) || isa<TailAddrInst>(user) ||
         isa<IndexAddrInst>(user) || isa<StoreBorrowInst>(user) ||
         isa<UncheckedAddrCastInst>(user) ||
+        isa<VectorBaseAddrInst>(user) ||
         isa<MarkUnresolvedNonCopyableValueInst>(user) ||
         isa<MarkUninitializedInst>(user) || isa<DropDeinitInst>(user) ||
         isa<ProjectBlockStorageInst>(user) || isa<UpcastInst>(user) ||
@@ -287,6 +288,7 @@ TransitiveAddressWalker<Impl>::walk(SILValue projectedAddress) {
         case BuiltinValueKind::GenericXor:
         case BuiltinValueKind::TaskRunInline:
         case BuiltinValueKind::ZeroInitializer:
+        case BuiltinValueKind::PrepareInitialization:
         case BuiltinValueKind::GetEnumTag:
         case BuiltinValueKind::InjectEnumTag:
         case BuiltinValueKind::AddressOfRawLayout:
diff --git a/include/swift/SIL/ApplySite.h b/include/swift/SIL/ApplySite.h
index 5fcf3ffa0be03..f01666c8ed921 100644
--- a/include/swift/SIL/ApplySite.h
+++ b/include/swift/SIL/ApplySite.h
@@ -562,6 +562,18 @@ class ApplySite {
     llvm_unreachable("covered switch");
   }
 
+  bool hasGuaranteedResult() const {
+    switch (ApplySiteKind(Inst->getKind())) {
+    case ApplySiteKind::ApplyInst:
+      return cast<ApplyInst>(Inst)->hasGuaranteedResult();
+    case ApplySiteKind::BeginApplyInst:
+    case ApplySiteKind::TryApplyInst:
+    case ApplySiteKind::PartialApplyInst:
+      return false;
+    }
+    llvm_unreachable("covered switch");
+  }
+
   /// Returns true if \p op is an operand that passes an indirect
   /// result argument to the apply site.
   bool isIndirectResultOperand(const Operand &op) const;
@@ -641,6 +653,10 @@ class ApplySite {
     return getArgumentParameterInfo(oper).hasOption(SILParameterInfo::Sending);
   }
 
+  /// Return true if 'operand' is addressable after type substitution in the
+  /// caller's context.
+  bool isAddressable(const Operand &operand) const;
+
   static ApplySite getFromOpaqueValue(void *p) { return ApplySite(p); }
 
   friend bool operator==(ApplySite lhs, ApplySite rhs) {
@@ -774,6 +790,25 @@ class FullApplySite : public ApplySite {
     llvm_unreachable("Covered switch isn't covered?!");
   }
 
+  // For a direct error result, as a result of an @error convention, if any.
+  SILValue getDirectErrorResult() const {
+    switch (getKind()) {
+    case FullApplySiteKind::ApplyInst:
+    case FullApplySiteKind::BeginApplyInst:
+      return SILValue();
+    case FullApplySiteKind::TryApplyInst: {
+      if (getNumIndirectSILErrorResults())
+        return SILValue(); // Not a direct @error convention.
+
+      auto *errBlock = cast<TryApplyInst>(getInstruction())->getErrorBB();
+      assert(errBlock->getNumArguments() == 1 &&
+             "Expected this try_apply to have a single direct error result");
+      return errBlock->getArgument(0);
+    }
+    }
+    llvm_unreachable("Covered switch isn't covered?!");
+  }
+
   unsigned getNumIndirectSILResults() const {
     return getSubstCalleeConv().getNumIndirectSILResults();
   }
@@ -890,6 +925,21 @@ class FullApplySite : public ApplySite {
            getNumIndirectSILErrorResults();
   }
 
+  std::optional<ActorIsolation> getActorIsolation() const {
+    if (auto isolation = getIsolationCrossing();
+        isolation && isolation->getCalleeIsolation())
+      return isolation->getCalleeIsolation();
+    auto *calleeFunction = getCalleeFunction();
+    if (!calleeFunction)
+      return {};
+    return calleeFunction->getActorIsolation();
+  }
+
+  bool isCallerIsolationInheriting() const {
+    auto isolation = getActorIsolation();
+    return isolation && isolation->isCallerIsolationInheriting();
+  }
+
   static FullApplySite getFromOpaqueValue(void *p) { return FullApplySite(p); }
 
   static bool classof(const SILInstruction *inst) {
diff --git a/include/swift/SIL/BasicBlockUtils.h b/include/swift/SIL/BasicBlockUtils.h
index d443b1f5abf03..1e15bcb78706d 100644
--- a/include/swift/SIL/BasicBlockUtils.h
+++ b/include/swift/SIL/BasicBlockUtils.h
@@ -68,6 +68,10 @@ class DeadEndBlocks {
   const SILFunction *f;
   bool didComputeValue = false;
 
+  /// When non-null, indicates whether dead-end blocks are present
+  /// in the current function.
+  std::optional<bool> hasAnyDeadEnds = std::nullopt;
+
   void compute();
 
 public:
@@ -85,6 +89,17 @@ class DeadEndBlocks {
     return reachableBlocks.count(block) == 0;
   }
 
+  /// Returns true iff none of the function's blocks is a dead-end.
+  /// Note: The underlying value is lazily computed & cached.
+  bool isEmpty() {
+    if (!hasAnyDeadEnds.has_value()) {
+      hasAnyDeadEnds = llvm::any_of(
+          *f, [this](const SILBasicBlock &BB) { return isDeadEnd(&BB); });
+    }
+
+    return !hasAnyDeadEnds.value();
+  }
+
   /// Return true if this dead end blocks has computed its internal cache yet.
   ///
   /// Used to determine if we need to verify a DeadEndBlocks.
diff --git a/include/swift/SIL/DynamicCasts.h b/include/swift/SIL/DynamicCasts.h
index 9f932f83268e8..65cbd829d27af 100644
--- a/include/swift/SIL/DynamicCasts.h
+++ b/include/swift/SIL/DynamicCasts.h
@@ -64,11 +64,15 @@ atBest(DynamicCastFeasibility feasibility, DynamicCastFeasibility bestCase) {
 /// Classify the feasibility of a dynamic cast.  The source and target
 /// types should be unlowered formal types.
 DynamicCastFeasibility classifyDynamicCast(
-    ModuleDecl *context,
+    SILFunction *function,
     CanType sourceType, CanType targetType,
     bool isSourceTypeExact = false,
     bool isWholeModuleOpts = false);
 
+/// Returns true if the conformance is not isolated or if its isolation matches
+/// the isolation `inFunction`.
+bool matchesActorIsolation(ProtocolConformanceRef conformance, SILFunction *inFunction);
+
 SILValue emitSuccessfulScalarUnconditionalCast(SILBuilder &B, SILLocation loc,
                                                SILDynamicCastInst inst);
 
@@ -93,6 +97,12 @@ bool canSILUseScalarCheckedCastInstructions(SILModule &M,
                                             CanType sourceType,
                                             CanType targetType);
 
+/// Can the given cast be performed by the scalar checked-cast instructions in
+/// the current SIL stage, or do we need to use the indirect instructions?
+bool canOptimizeToScalarCheckedCastInstructions(
+    SILFunction *func, CanType sourceType, CanType targetType,
+    CastConsumptionKind consumption);
+
 /// Can the given cast be performed by the scalar checked-cast
 /// instructions at IRGen, or do we need to use the indirect instructions?
 bool canIRGenUseScalarCheckedCastInstructions(SILModule &M,
@@ -103,7 +113,7 @@ bool canIRGenUseScalarCheckedCastInstructions(SILModule &M,
 /// using a scalar cast operation.
 void emitIndirectConditionalCastWithScalar(
     SILBuilder &B, ModuleDecl *M, SILLocation loc,
-    CastingIsolatedConformances isolatedConformances,
+    CheckedCastInstOptions options,
     CastConsumptionKind consumption, SILValue src, CanType sourceType,
     SILValue dest, CanType targetType, SILBasicBlock *trueBB,
     SILBasicBlock *falseBB, ProfileCounter TrueCount = ProfileCounter(),
@@ -386,7 +396,7 @@ struct SILDynamicCastInst {
 
   DynamicCastFeasibility classifyFeasibility(bool allowWholeModule) const {
     return swift::classifyDynamicCast(
-        getModule().getSwiftModule(),
+        getFunction(),
         getSourceFormalType(), getTargetFormalType(),
         isSourceTypeExact(), allowWholeModule && getModule().isWholeModule());
   }
@@ -454,18 +464,18 @@ struct SILDynamicCastInst {
         getModule(), getSourceFormalType(), getTargetFormalType());
   }
 
-  CastingIsolatedConformances getIsolatedConformances() const {
+  CheckedCastInstOptions getCheckedCastOptions() const {
     switch (getKind()) {
     case SILDynamicCastKind::CheckedCastAddrBranchInst:
-      return cast<CheckedCastAddrBranchInst>(inst)->getIsolatedConformances();
+      return cast<CheckedCastAddrBranchInst>(inst)->getCheckedCastOptions();
     case SILDynamicCastKind::CheckedCastBranchInst:
-      return cast<CheckedCastBranchInst>(inst)->getIsolatedConformances();
+      return cast<CheckedCastBranchInst>(inst)->getCheckedCastOptions();
     case SILDynamicCastKind::UnconditionalCheckedCastAddrInst:
       return cast<UnconditionalCheckedCastAddrInst>(inst)
-          ->getIsolatedConformances();
+          ->getCheckedCastOptions();
     case SILDynamicCastKind::UnconditionalCheckedCastInst:
       return cast<UnconditionalCheckedCastInst>(inst)
-          ->getIsolatedConformances();
+          ->getCheckedCastOptions();
     }
   }
 };
diff --git a/include/swift/SIL/GenericSpecializationMangler.h b/include/swift/SIL/GenericSpecializationMangler.h
index 4bd6bf9710084..6ecbdaffaf07d 100644
--- a/include/swift/SIL/GenericSpecializationMangler.h
+++ b/include/swift/SIL/GenericSpecializationMangler.h
@@ -83,7 +83,9 @@ class GenericSpecializationMangler : public SpecializationMangler {
     return Function->getLoweredFunctionType()->getInvocationGenericSignature();
   }
 
-  void appendSubstitutions(GenericSignature sig, SubstitutionMap subs);
+  void appendSubstitutions(GenericSignature calleeSig,
+                           SubstitutionMap calleeSubs,
+                           GenericSignature callerSig);
 
   std::string manglePrespecialized(GenericSignature sig,
                                       SubstitutionMap subs);
@@ -112,7 +114,9 @@ class GenericSpecializationMangler : public SpecializationMangler {
   std::string mangleReabstracted(SubstitutionMap subs, bool alternativeMangling,
                                  const SmallBitVector &paramsRemoved = SmallBitVector());
 
-  std::string mangleForDebugInfo(GenericSignature sig, SubstitutionMap subs,
+  std::string mangleForDebugInfo(GenericSignature calleeSig,
+                                 SubstitutionMap calleeSubs,
+                                 GenericSignature callerSubs,
                                  bool forInlining);
 
   std::string manglePrespecialized(SubstitutionMap subs) {
diff --git a/include/swift/SIL/InstWrappers.h b/include/swift/SIL/InstWrappers.h
index d2c352e50dda5..6e64698069ac1 100644
--- a/include/swift/SIL/InstWrappers.h
+++ b/include/swift/SIL/InstWrappers.h
@@ -38,9 +38,9 @@ struct LoadOperation {
   explicit operator bool() const { return !value.isNull(); }
 
   SingleValueInstruction *getLoadInst() const {
-    if (value.is<LoadInst *>())
-      return value.get<LoadInst *>();
-    return value.get<LoadBorrowInst *>();
+    if (isa<LoadInst *>(value))
+      return cast<LoadInst *>(value);
+    return cast<LoadBorrowInst *>(value);
   }
 
   SingleValueInstruction *operator*() const { return getLoadInst(); }
@@ -50,9 +50,9 @@ struct LoadOperation {
   SingleValueInstruction *operator->() { return getLoadInst(); }
 
   SILValue getOperand() const {
-    if (value.is<LoadInst *>())
-      return value.get<LoadInst *>()->getOperand();
-    return value.get<LoadBorrowInst *>()->getOperand();
+    if (isa<LoadInst *>(value))
+      return cast<LoadInst *>(value)->getOperand();
+    return cast<LoadBorrowInst *>(value)->getOperand();
   }
 
   /// Return the ownership qualifier of the underlying load if we have a load or
@@ -65,7 +65,7 @@ struct LoadOperation {
       return std::nullopt;
     }
 
-    return value.get<LoadInst *>()->getOwnershipQualifier();
+    return cast<LoadInst *>(value)->getOwnershipQualifier();
   }
 };
 
@@ -180,19 +180,19 @@ class SelectEnumOperation {
   operator SingleValueInstruction *() const {
     if (auto *seai = value.dyn_cast<SelectEnumAddrInst *>())
       return seai;
-    return value.get<SelectEnumInst *>();
+    return cast<SelectEnumInst *>(value);
   }
 
   SingleValueInstruction *operator*() const {
     if (auto *seai = value.dyn_cast<SelectEnumAddrInst *>())
       return seai;
-    return value.get<SelectEnumInst *>();
+    return cast<SelectEnumInst *>(value);
   }
 
   SingleValueInstruction *operator->() const {
     if (auto *seai = value.dyn_cast<SelectEnumAddrInst *>())
       return seai;
-    return value.get<SelectEnumInst *>();
+    return cast<SelectEnumInst *>(value);
   }
 
   operator bool() const { return bool(value); }
@@ -200,7 +200,7 @@ class SelectEnumOperation {
   SILValue getOperand() {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->getOperand();
-    return value.get<SelectEnumAddrInst *>()->getOperand();
+    return cast<SelectEnumAddrInst *>(value)->getOperand();
   }
 
   SILValue getEnumOperand() { return getOperand(); }
@@ -208,25 +208,25 @@ class SelectEnumOperation {
   const Operand &getEnumOperandRef() {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->getEnumOperandRef();
-    return value.get<SelectEnumAddrInst *>()->getEnumOperandRef();
+    return cast<SelectEnumAddrInst *>(value)->getEnumOperandRef();
   }
 
   unsigned getNumCases() const {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->getNumCases();
-    return value.get<SelectEnumAddrInst *>()->getNumCases();
+    return cast<SelectEnumAddrInst *>(value)->getNumCases();
   }
 
   std::pair<EnumElementDecl *, SILValue> getCase(unsigned i) const {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->getCase(i);
-    return value.get<SelectEnumAddrInst *>()->getCase(i);
+    return cast<SelectEnumAddrInst *>(value)->getCase(i);
   }
 
   std::pair<EnumElementDecl *, Operand *> getCaseOperand(unsigned i) const {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->getCaseOperand(i);
-    return value.get<SelectEnumAddrInst *>()->getCaseOperand(i);
+    return cast<SelectEnumAddrInst *>(value)->getCaseOperand(i);
   }
 
   /// Return the value that will be used as the result for the specified enum
@@ -234,13 +234,13 @@ class SelectEnumOperation {
   SILValue getCaseResult(EnumElementDecl *D) {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->getCaseResult(D);
-    return value.get<SelectEnumAddrInst *>()->getCaseResult(D);
+    return cast<SelectEnumAddrInst *>(value)->getCaseResult(D);
   }
 
   Operand *getCaseResultOperand(EnumElementDecl *D) {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->getCaseResultOperand(D);
-    return value.get<SelectEnumAddrInst *>()->getCaseResultOperand(D);
+    return cast<SelectEnumAddrInst *>(value)->getCaseResultOperand(D);
   }
 
   /// If the default refers to exactly one case decl, return it.
@@ -249,19 +249,19 @@ class SelectEnumOperation {
   bool hasDefault() const {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->hasDefault();
-    return value.get<SelectEnumAddrInst *>()->hasDefault();
+    return cast<SelectEnumAddrInst *>(value)->hasDefault();
   }
 
   SILValue getDefaultResult() const {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->getDefaultResult();
-    return value.get<SelectEnumAddrInst *>()->getDefaultResult();
+    return cast<SelectEnumAddrInst *>(value)->getDefaultResult();
   }
 
   Operand *getDefaultResultOperand() const {
     if (auto *sei = value.dyn_cast<SelectEnumInst *>())
       return sei->getDefaultResultOperand();
-    return value.get<SelectEnumAddrInst *>()->getDefaultResultOperand();
+    return cast<SelectEnumAddrInst *>(value)->getDefaultResultOperand();
   }
 };
 
diff --git a/include/swift/SIL/InstructionUtils.h b/include/swift/SIL/InstructionUtils.h
index a1ec3ea2fbbc4..cad6d3d7c5e44 100644
--- a/include/swift/SIL/InstructionUtils.h
+++ b/include/swift/SIL/InstructionUtils.h
@@ -41,6 +41,8 @@ SILValue stripCastsWithoutMarkDependence(SILValue V);
 /// begin_borrow instructions.
 SILValue lookThroughOwnershipInsts(SILValue v);
 
+SILValue lookThroughMoveOnlyCheckerPattern(SILValue value);
+
 /// Reverse of lookThroughOwnershipInsts.
 ///
 /// Return true if \p visitor returned true for all uses.
@@ -158,10 +160,6 @@ bool isInstrumentation(SILInstruction *Instruction);
 /// argument of the partial apply if it is.
 SILValue isPartialApplyOfReabstractionThunk(PartialApplyInst *PAI);
 
-/// Returns true if \p PAI is only used by an assign_by_wrapper instruction as
-/// init or set function.
-bool onlyUsedByAssignByWrapper(PartialApplyInst *PAI);
-
 /// Returns true if \p PAI is only used by an \c assign_or_init
 /// instruction as init or set function.
 bool onlyUsedByAssignOrInit(PartialApplyInst *PAI);
@@ -247,6 +245,13 @@ lookUpFunctionInWitnessTable(WitnessMethodInst *wmi, SILModule::LinkingMode link
 /// struct-with-deinit drops the deinit.
 bool shouldExpand(SILModule &module, SILType ty);
 
+/// Returns true if `arg` is mutated.
+/// if `ignoreDestroys` is true, `destroy_addr` instructions are ignored.
+/// `defaultIsMutating` specifies the state of instructions which are not explicitly handled.
+/// For historical reasons this utility is implemented in SILVerifier.cpp.
+bool isIndirectArgumentMutated(SILFunctionArgument *arg, bool ignoreDestroys = false,
+                               bool defaultIsMutating = false);
+
 } // end namespace swift
 
 #endif
diff --git a/include/swift/SIL/Lifetime.h b/include/swift/SIL/Lifetime.h
index 361cd5da20cba..7ba93565e8e12 100644
--- a/include/swift/SIL/Lifetime.h
+++ b/include/swift/SIL/Lifetime.h
@@ -26,7 +26,7 @@ namespace swift {
 /// aggressively its destroys may be hoisted.
 ///
 /// By default, types have lifetimes inferred from their structure, see
-/// TypeLowering::RecursiveProperties::isLexical.  It can be overridden both on
+/// SILTypeProperties::isLexical.  It can be overridden both on
 /// the type level and the value level via attributes.
 struct Lifetime {
   enum Storage : uint8_t {
diff --git a/include/swift/SIL/MemAccessUtils.h b/include/swift/SIL/MemAccessUtils.h
index 07a0002e37559..bf7b48caf4e34 100644
--- a/include/swift/SIL/MemAccessUtils.h
+++ b/include/swift/SIL/MemAccessUtils.h
@@ -164,6 +164,14 @@ inline SILValue stripAccessMarkers(SILValue v) {
   return v;
 }
 
+inline bool isGuaranteedAddressReturn(SILValue value) {
+  auto *defInst = dyn_cast_or_null<ApplyInst>(value->getDefiningInstruction());
+  if (!defInst) {
+    return false;
+  }
+  return defInst->hasGuaranteedAddressResult();
+}
+
 /// Return the source address after stripping as many access projections as
 /// possible without losing the address type.
 ///
@@ -375,12 +383,12 @@ class AccessRepresentation {
     // Define bits for use in AccessStorageAnalysis. Each identified storage
     // object is mapped to one instance of this subclass.
     SWIFT_INLINE_BITFIELD_FULL(StorageAccessInfo, AccessRepresentation,
-                               64 - NumAccessRepresentationBits,
+                               64 - NumberOfAccessRepresentationBits,
                                accessKind : NumSILAccessKindBits,
                                noNestedConflict : 1,
-                               storageIndex : 64 - (NumAccessRepresentationBits
-                                                    + NumSILAccessKindBits
-                                                    + 1));
+                               storageIndex : 64 -
+                                   (NumberOfAccessRepresentationBits +
+                                    NumSILAccessKindBits + 1));
 
     // Define bits for use in the AccessEnforcementOpts pass. Each begin_access
     // in the function is mapped to one instance of this subclass.  Reserve a
@@ -390,13 +398,11 @@ class AccessRepresentation {
     //
     // `AccessRepresentation` refers to the AccessRepresentationBitfield defined
     // above, setting aside enough bits for common data.
-    SWIFT_INLINE_BITFIELD_FULL(AccessEnforcementOptsInfo,
-                               AccessRepresentation,
-                               64 - NumAccessRepresentationBits,
-                               seenNestedConflict : 1,
-                               seenIdenticalStorage : 1,
-                               beginAccessIndex :
-                                 62 - NumAccessRepresentationBits);
+    SWIFT_INLINE_BITFIELD_FULL(AccessEnforcementOptsInfo, AccessRepresentation,
+                               64 - NumberOfAccessRepresentationBits,
+                               seenNestedConflict : 1, seenIdenticalStorage : 1,
+                               beginAccessIndex : 62 -
+                                   NumberOfAccessRepresentationBits);
 
     // Define data flow bits for use in the AccessEnforcementDom pass. Each
     // begin_access in the function is mapped to one instance of this subclass.
@@ -1281,7 +1287,7 @@ struct AccessPathWithBase {
 //
 // Returns false if the access path couldn't be computed.
 bool visitProductLeafAccessPathNodes(
-    SILValue address, TypeExpansionContext tec, SILModule &module,
+    SILValue address, TypeExpansionContext tec, SILFunction &function,
     std::function<void(AccessPath::PathNode, SILType)> visitor);
 
 inline AccessPath AccessPath::compute(SILValue address) {
@@ -1606,6 +1612,7 @@ inline bool isAccessStorageTypeCast(SingleValueInstruction *svi) {
   // Simply pass-thru the incoming address.  But change its type!
   case SILInstructionKind::MoveOnlyWrapperToCopyableAddrInst:
   case SILInstructionKind::CopyableToMoveOnlyWrapperAddrInst:
+  case SILInstructionKind::MoveOnlyWrapperToCopyableBoxInst:
   // Simply pass-thru the incoming address.  But change its type!
   case SILInstructionKind::UncheckedAddrCastInst:
   // Casting to RawPointer does not affect the AccessPath. When converting
@@ -1652,7 +1659,6 @@ inline bool isAccessStorageIdentityCast(SingleValueInstruction *svi) {
   case SILInstructionKind::MarkDependenceInst:
   case SILInstructionKind::CopyValueInst:
   case SILInstructionKind::BeginBorrowInst:
-  case SILInstructionKind::MoveOnlyWrapperToCopyableBoxInst:
     return true;
   }
 }
@@ -1688,6 +1694,22 @@ inline bool isAccessStorageCast(SingleValueInstruction *svi) {
   return isAccessStorageTypeCast(svi) || isAccessStorageIdentityCast(svi);
 }
 
+// Strip access markers and casts that preserve the access storage.
+//
+// Compare to stripAccessAndIdentityCasts.  This function strips cast that
+// change the type.
+inline SILValue stripAccessAndAccessStorageCasts(SILValue v) {
+  if (auto *bai = dyn_cast<BeginAccessInst>(v)) {
+    return stripAccessAndAccessStorageCasts(bai->getOperand());
+  }
+  if (auto *svi = dyn_cast<SingleValueInstruction>(v)) {
+    if (isAccessStorageCast(svi)) {
+      return stripAccessAndAccessStorageCasts(svi->getAllOperands()[0].get());
+    }
+  }
+  return v;
+}
+
 /// Abstract CRTP class for a visiting instructions that are part of the use-def
 /// chain from an accessed address up to the storage base.
 ///
@@ -1786,6 +1808,14 @@ Result AccessUseDefChainVisitor<Impl, Result>::visit(SILValue sourceAddr) {
     if (isExternalGlobalAddressor(cast<ApplyInst>(sourceAddr)))
       return asImpl().visitUnidentified(sourceAddr);
 
+    if (isGuaranteedAddressReturn(sourceAddr)) {
+      auto *selfOp = &cast<ApplyInst>(sourceAddr)->getSelfArgumentOperand();
+      if (selfOp->get()->getType().isObject()) {
+        return asImpl().visitUnidentified(sourceAddr);
+      }
+      return asImpl().visitAccessProjection(cast<ApplyInst>(sourceAddr), selfOp);
+    }
+
     // Don't currently allow any other calls to return an accessed address.
     return asImpl().visitNonAccess(sourceAddr);
   }
diff --git a/include/swift/SIL/OSSACompleteLifetime.h b/include/swift/SIL/OSSACompleteLifetime.h
new file mode 100644
index 0000000000000..a36e1052df618
--- /dev/null
+++ b/include/swift/SIL/OSSACompleteLifetime.h
@@ -0,0 +1,228 @@
+//===--- OwnershipLifetimeCompletion.h ------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// OSSA lifetime completion adds lifetime ending instructions to make
+/// linear lifetimes complete.
+///
+/// Completion is bottom-up recursive over nested borrow scopes. Additionally,
+/// this may be extended to support dependent owned lifetimes in the future to
+/// handle owned non-escaping values.
+///
+/// Lexical lifetimes can only be incomplete as a result of dead-end blocks. In
+/// this case, their lifetime ends immediately before the dead-end block.
+///
+/// Nonlexical lifetimes can be incomplete for any reason. Their lifetime ends
+/// at the liveness boundary.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SILOPTIMIZER_UTILS_OSSSALIFETIMECOMPLETION_H
+#define SWIFT_SILOPTIMIZER_UTILS_OSSSALIFETIMECOMPLETION_H
+
+#include "swift/SIL/NodeDatastructures.h"
+#include "swift/SIL/OwnershipLiveness.h"
+#include "swift/SIL/SILFunction.h"
+
+namespace swift {
+
+class DeadEndBlocks;
+
+enum class LifetimeCompletion { NoLifetime, AlreadyComplete, WasCompleted };
+
+class OSSACompleteLifetime {
+public:
+  enum HandleTrivialVariable_t { IgnoreTrivialVariable, ExtendTrivialVariable };
+
+private:
+  /// If domInfo is nullptr, then InteriorLiveness never assumes dominance. As a
+  /// result it may report extra unenclosedPhis. In that case, any attempt to
+  /// create a new phi would result in an immediately redundant phi.
+  const DominanceInfo *domInfo = nullptr;
+
+  DeadEndBlocks &deadEndBlocks;
+
+  /// Cache intructions already handled by the recursive algorithm to avoid
+  /// recomputing their lifetimes.
+  ValueSet completedValues;
+
+  /// Extend trivial variables for lifetime diagnostics (only in SILGenCleanup).
+  HandleTrivialVariable_t handleTrivialVariable;
+
+  /// Whether verification of the computed liveness should be run even when the
+  /// global setting is off.
+  /// TODO: Remove this option.
+  bool ForceLivenessVerification;
+
+  /// If true, lifetimes are completed with `end_lifetime` instead of `destroy_value`.
+  /// This can be used e.g. for enum values of non-trivial enum types, which are
+  /// known to be a trivial case.
+  bool nonDestroyingEnd;
+
+public:
+  OSSACompleteLifetime(
+      SILFunction *function, const DominanceInfo *domInfo,
+      DeadEndBlocks &deadEndBlocks,
+      HandleTrivialVariable_t handleTrivialVariable = IgnoreTrivialVariable,
+      bool forceLivenessVerification = false,
+      bool nonDestroyingEnd = false)
+      : domInfo(domInfo), deadEndBlocks(deadEndBlocks),
+        completedValues(function), handleTrivialVariable(handleTrivialVariable),
+        ForceLivenessVerification(forceLivenessVerification),
+        nonDestroyingEnd(nonDestroyingEnd) {}
+
+  /// The kind of boundary at which to complete the lifetime.
+  ///
+  /// Liveness: "As early as possible."  Consume the value after the last
+  ///           non-consuming uses.
+  /// Availability: "As late as possible."  Consume the value in the last blocks
+  ///               beyond the non-consuming uses in which the value has been
+  ///               consumed on no incoming paths.
+  struct Boundary {
+    enum Value : uint8_t {
+      Liveness,
+      Availability,
+    };
+    Value value;
+
+    Boundary(Value value) : value(value){};
+    operator Value() const { return value; }
+  };
+
+  /// Insert a lifetime-ending instruction on every path to complete the OSSA
+  /// lifetime of \p value along \p boundary.
+  ///
+  /// If \p boundary is not specified, the following boundary will be used:
+  ///   \p value is lexical -> Boundary::Availability
+  ///   \p value is non-lexical -> Boundary::Liveness
+  ///
+  /// Lifetime completion is only relevant for owned
+  /// values or borrow introducers.
+  ///
+  /// Currently \p boundary == {Boundary::Availability} is used by Mem2Reg and
+  /// TempRValueOpt and PredicatbleMemOpt to complete lexical enum values on
+  /// trivial paths.
+  ///
+  /// Returns true if any new instructions were created to complete the
+  /// lifetime.
+  LifetimeCompletion completeOSSALifetime(SILValue value, Boundary boundary) {
+    switch (value->getOwnershipKind()) {
+    case OwnershipKind::None: {
+      if (auto scopedAddress = ScopedAddressValue(value)) {
+        break;
+      }
+      // During SILGenCleanup, extend move_value [var_decl].
+      if (handleTrivialVariable == ExtendTrivialVariable &&
+          value->isFromVarDecl()) {
+        break;
+      }
+      return LifetimeCompletion::NoLifetime;
+    }
+    case OwnershipKind::Owned:
+      break;
+    case OwnershipKind::Any:
+      llvm::report_fatal_error("value with any ownership kind!?");
+    case OwnershipKind::Guaranteed:
+    case OwnershipKind::Unowned: {
+      BorrowedValue borrowedValue(value);
+      if (!borrowedValue)
+        return LifetimeCompletion::NoLifetime;
+
+      if (!borrowedValue.isLocalScope())
+        return LifetimeCompletion::AlreadyComplete;
+    }
+    }
+
+    if (!completedValues.insert(value))
+      return LifetimeCompletion::AlreadyComplete;
+
+    return analyzeAndUpdateLifetime(value, boundary)
+               ? LifetimeCompletion::WasCompleted
+               : LifetimeCompletion::AlreadyComplete;
+  }
+
+  enum class LifetimeEnd : uint8_t {
+    /// The lifetime ends at the boundary.
+    Boundary,
+    /// The lifetime "ends" in a loop.
+    Loop,
+  };
+
+  static void visitAvailabilityBoundary(
+      SILValue value, const SSAPrunedLiveness &liveness,
+      llvm::function_ref<void(SILInstruction *, LifetimeEnd end)> visit);
+
+protected:
+  bool analyzeAndUpdateLifetime(SILValue value, Boundary boundary);
+  bool analyzeAndUpdateLifetime(ScopedAddressValue value, Boundary boundary);
+};
+
+//===----------------------------------------------------------------------===//
+// UnreachableLifetimeCompletion
+//===----------------------------------------------------------------------===//
+
+/// Fixup OSSA before deleting an unreachable code path.
+///
+/// Only needed when a code path reaches a no-return function, making the
+/// path now partially unreachable. Conditional branch folding requires no fixup
+/// because it causes the entire path to become unreachable.
+class UnreachableLifetimeCompletion {
+  SILFunction *function;
+
+  // If domInfo is nullptr, lifetime completion may attempt to recreate
+  // redundant phis, which should be immediately discarded.
+  const DominanceInfo *domInfo = nullptr;
+  DeadEndBlocks &deadEndBlocks;
+
+  BasicBlockSetVector unreachableBlocks;
+  InstructionSet unreachableInsts; // not including those in unreachableBlocks
+  ValueSetVector incompleteValues;
+  bool updatingLifetimes = false;
+
+public:
+  UnreachableLifetimeCompletion(SILFunction *function, DominanceInfo *domInfo,
+                                DeadEndBlocks &deadEndBlocks)
+      : function(function), domInfo(domInfo), deadEndBlocks(deadEndBlocks),
+        unreachableBlocks(function), unreachableInsts(function),
+        incompleteValues(function) {}
+
+  /// Record information about this unreachable instruction and return true if
+  /// ends any simple OSSA lifetimes.
+  ///
+  /// Note: this must be called in forward order so that lifetime completion
+  /// runs from the inside out.
+  void visitUnreachableInst(SILInstruction *instruction);
+
+  void visitUnreachableBlock(SILBasicBlock *block) {
+    unreachableBlocks.insert(block);
+  }
+
+  /// Complete the lifetime of any value defined outside of the unreachable
+  /// region that was previously destroyed in the unreachable region.
+  bool completeLifetimes();
+};
+
+inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
+                                     OSSACompleteLifetime::Boundary boundary) {
+  switch (boundary) {
+  case OSSACompleteLifetime::Boundary::Liveness:
+    OS << "liveness";
+    break;
+  case OSSACompleteLifetime::Boundary::Availability:
+    OS << "availability";
+    break;
+  }
+  return OS;
+}
+
+} // namespace swift
+
+#endif
diff --git a/include/swift/SIL/OSSALifetimeCompletion.h b/include/swift/SIL/OSSALifetimeCompletion.h
deleted file mode 100644
index 89a4fa025ee3e..0000000000000
--- a/include/swift/SIL/OSSALifetimeCompletion.h
+++ /dev/null
@@ -1,213 +0,0 @@
-//===--- OwnershipLifetimeCompletion.h ------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// OSSA lifetime completion adds lifetime ending instructions to make
-/// linear lifetimes complete.
-///
-/// Completion is bottom-up recursive over nested borrow scopes. Additionally,
-/// this may be extended to support dependent owned lifetimes in the future to
-/// handle owned non-escaping values.
-///
-/// Lexical lifetimes can only be incomplete as a result of dead-end blocks. In
-/// this case, their lifetime ends immediately before the dead-end block.
-///
-/// Nonlexical lifetimes can be incomplete for any reason. Their lifetime ends
-/// at the liveness boundary.
-///
-//===----------------------------------------------------------------------===//
-
-#ifndef SWIFT_SILOPTIMIZER_UTILS_OSSSALIFETIMECOMPLETION_H
-#define SWIFT_SILOPTIMIZER_UTILS_OSSSALIFETIMECOMPLETION_H
-
-#include "swift/SIL/NodeDatastructures.h"
-#include "swift/SIL/OwnershipLiveness.h"
-#include "swift/SIL/SILFunction.h"
-
-namespace swift {
-
-class DeadEndBlocks;
-
-enum class LifetimeCompletion { NoLifetime, AlreadyComplete, WasCompleted };
-
-class OSSALifetimeCompletion {
-public:
-  enum HandleTrivialVariable_t { IgnoreTrivialVariable, ExtendTrivialVariable };
-
-private:
-  // If domInfo is nullptr, then InteriorLiveness never assumes dominance. As a
-  // result it may report extra unenclosedPhis. In that case, any attempt to
-  // create a new phi would result in an immediately redundant phi.
-  const DominanceInfo *domInfo = nullptr;
-
-  DeadEndBlocks &deadEndBlocks;
-
-  // Cache intructions already handled by the recursive algorithm to avoid
-  // recomputing their lifetimes.
-  ValueSet completedValues;
-
-  // Extend trivial variables for lifetime diagnostics (only in SILGenCleanup).
-  HandleTrivialVariable_t handleTrivialVariable;
-
-public:
-  OSSALifetimeCompletion(SILFunction *function, const DominanceInfo *domInfo,
-                         DeadEndBlocks &deadEndBlocks,
-                         HandleTrivialVariable_t handleTrivialVariable = IgnoreTrivialVariable)
-      : domInfo(domInfo), deadEndBlocks(deadEndBlocks),
-        completedValues(function), handleTrivialVariable(handleTrivialVariable) {}
-
-  // The kind of boundary at which to complete the lifetime.
-  //
-  // Liveness: "As early as possible."  Consume the value after the last
-  //           non-consuming uses.
-  // Availability: "As late as possible."  Consume the value in the last blocks
-  //               beyond the non-consuming uses in which the value has been
-  //               consumed on no incoming paths.
-  struct Boundary {
-    enum Value : uint8_t {
-      Liveness,
-      Availability,
-    };
-    Value value;
-
-    Boundary(Value value) : value(value){};
-    operator Value() const { return value; }
-  };
-
-  /// Insert a lifetime-ending instruction on every path to complete the OSSA
-  /// lifetime of \p value along \p boundary.
-  ///
-  /// If \p boundary is not specified, the following boundary will be used:
-  ///   \p value is lexical -> Boundary::Availability
-  ///   \p value is non-lexical -> Boundary::Liveness
-  ///
-  /// Lifetime completion is only relevant for owned
-  /// values or borrow introducers.
-  ///
-  /// Currently \p boundary == {Boundary::Availability} is used by Mem2Reg and
-  /// TempRValueOpt and PredicatbleMemOpt to complete lexical enum values on
-  /// trivial paths.
-  ///
-  /// Returns true if any new instructions were created to complete the
-  /// lifetime.
-  LifetimeCompletion completeOSSALifetime(SILValue value, Boundary boundary) {
-    switch (value->getOwnershipKind()) {
-    case OwnershipKind::None: {
-      if (auto scopedAddress = ScopedAddressValue(value)) {
-        break;
-      }
-      // During SILGenCleanup, extend move_value [var_decl].
-      if (handleTrivialVariable == ExtendTrivialVariable
-          && value->isFromVarDecl()) {
-        break;
-      }
-      return LifetimeCompletion::NoLifetime;
-    }
-    case OwnershipKind::Owned:
-      break;
-    case OwnershipKind::Any:
-      llvm::report_fatal_error("value with any ownership kind!?");
-    case OwnershipKind::Guaranteed:
-    case OwnershipKind::Unowned: {
-      BorrowedValue borrowedValue(value);
-      if (!borrowedValue)
-        return LifetimeCompletion::NoLifetime;
-
-      if (!borrowedValue.isLocalScope())
-        return LifetimeCompletion::AlreadyComplete;
-    }
-    }
-
-    if (!completedValues.insert(value))
-      return LifetimeCompletion::AlreadyComplete;
-
-    return analyzeAndUpdateLifetime(value, boundary)
-               ? LifetimeCompletion::WasCompleted
-               : LifetimeCompletion::AlreadyComplete;
-  }
-
-  enum class LifetimeEnd : uint8_t {
-    /// The lifetime ends at the boundary.
-    Boundary,
-    /// The lifetime "ends" in a loop.
-    Loop,
-  };
-
-  static void visitAvailabilityBoundary(
-      SILValue value, const SSAPrunedLiveness &liveness,
-      llvm::function_ref<void(SILInstruction *, LifetimeEnd end)> visit);
-
-protected:
-  bool analyzeAndUpdateLifetime(SILValue value, Boundary boundary);
-  bool analyzeAndUpdateLifetime(ScopedAddressValue value, Boundary boundary);
-};
-
-//===----------------------------------------------------------------------===//
-// UnreachableLifetimeCompletion
-//===----------------------------------------------------------------------===//
-
-/// Fixup OSSA before deleting an unreachable code path.
-///
-/// Only needed when a code path reaches a no-return function, making the
-/// path now partially unreachable. Conditional branch folding requires no fixup
-/// because it causes the entire path to become unreachable.
-class UnreachableLifetimeCompletion {
-  SILFunction *function;
-
-  // If domInfo is nullptr, lifetime completion may attempt to recreate
-  // redundant phis, which should be immediately discarded.
-  const DominanceInfo *domInfo = nullptr;
-  DeadEndBlocks &deadEndBlocks;
-
-  BasicBlockSetVector unreachableBlocks;
-  InstructionSet unreachableInsts; // not including those in unreachableBlocks
-  ValueSetVector incompleteValues;
-  bool updatingLifetimes = false;
-
-public:
-  UnreachableLifetimeCompletion(SILFunction *function, DominanceInfo *domInfo,
-                                DeadEndBlocks &deadEndBlocks)
-      : function(function), domInfo(domInfo), deadEndBlocks(deadEndBlocks),
-        unreachableBlocks(function), unreachableInsts(function),
-        incompleteValues(function) {}
-
-  /// Record information about this unreachable instruction and return true if
-  /// ends any simple OSSA lifetimes.
-  ///
-  /// Note: this must be called in forward order so that lifetime completion
-  /// runs from the inside out.
-  void visitUnreachableInst(SILInstruction *instruction);
-
-  void visitUnreachableBlock(SILBasicBlock *block) {
-    unreachableBlocks.insert(block);
-  }
-
-  /// Complete the lifetime of any value defined outside of the unreachable
-  /// region that was previously destroyed in the unreachable region.
-  bool completeLifetimes();
-};
-
-inline llvm::raw_ostream &
-operator<<(llvm::raw_ostream &OS, OSSALifetimeCompletion::Boundary boundary) {
-  switch (boundary) {
-  case OSSALifetimeCompletion::Boundary::Liveness:
-    OS << "liveness";
-    break;
-  case OSSALifetimeCompletion::Boundary::Availability:
-    OS << "availability";
-    break;
-  }
-  return OS;
-}
-
-} // namespace swift
-
-#endif
diff --git a/include/swift/SIL/OwnershipUtils.h b/include/swift/SIL/OwnershipUtils.h
index bf54303ecc32d..201a2fe154c10 100644
--- a/include/swift/SIL/OwnershipUtils.h
+++ b/include/swift/SIL/OwnershipUtils.h
@@ -630,6 +630,21 @@ struct BorrowedValue {
   /// necessarilly dominated by the borrow scope.
   void computeTransitiveLiveness(MultiDefPrunedLiveness &liveness) const;
 
+  /// Whether \p insts are completely within this borrow introducer's local
+  /// scope.
+  ///
+  /// Precondition: \p insts are dominated by the local borrow introducer.
+  ///
+  /// This ignores reborrows. The assumption is that, since \p insts are
+  /// dominated by this local scope, checking the extended borrow scope should
+  /// not be necessary to determine they are within the scope.
+  ///
+  /// \p deadEndBlocks is optional during transition. It will be completely
+  /// removed in an upcoming commit.
+  template <typename Instructions>
+  bool areWithinExtendedScope(Instructions insts,
+                              DeadEndBlocks *deadEndBlocks) const;
+
   /// Returns true if \p uses are completely within this borrow introducer's
   /// local scope.
   ///
@@ -1426,6 +1441,43 @@ bool isRedundantMoveValue(MoveValueInst *mvi);
 /// `forEndBorrowValue`, which is the operand value of an `end_borrow`.
 void updateReborrowFlags(SILValue forEndBorrowValue);
 
+/// A location at which a value is used.  Abstracts over explicit uses
+/// (operands) and implicit uses (instructions).
+struct UsePoint {
+  using Value = llvm::PointerUnion<SILInstruction *, Operand *>;
+  Value value;
+
+  UsePoint(Operand *op) : value(op) {}
+  UsePoint(SILInstruction *inst) : value(inst) {}
+  UsePoint(Value value) : value(value) {}
+
+  SILInstruction *getInstruction() const {
+    if (auto *op = dyn_cast<Operand *>(value)) {
+      return op->getUser();
+    }
+    return cast<SILInstruction *>(value);
+  }
+
+  Operand *getOperandOrNull() const { return dyn_cast<Operand *>(value); }
+
+  Operand *getOperand() const { return cast<Operand *>(value); }
+};
+
+struct UsePointToInstruction {
+  SILInstruction *operator()(const UsePoint point) const {
+    return point.getInstruction();
+  }
+};
+
+using UsePointInstructionRange =
+    TransformRange<ArrayRef<UsePoint>, UsePointToInstruction>;
+
+struct PointToOperand {
+  Operand *operator()(const UsePoint point) const { return point.getOperand(); }
+};
+
+using PointOperandRange = TransformRange<ArrayRef<UsePoint>, PointToOperand>;
+
 } // namespace swift
 
 #endif
diff --git a/include/swift/SIL/PrunedLiveness.h b/include/swift/SIL/PrunedLiveness.h
index 8f2853b6bf30f..339642e7f4278 100644
--- a/include/swift/SIL/PrunedLiveness.h
+++ b/include/swift/SIL/PrunedLiveness.h
@@ -729,6 +729,20 @@ class PrunedLiveRange : public PrunedLiveness {
   bool isWithinBoundary(SILInstruction *inst,
                         DeadEndBlocks *deadEndBlocks) const;
 
+  /// Whether all \p insts are between this def and the liveness boundary;
+  /// \p deadEndBlocks is optional.
+  template <typename Instructions>
+  bool areWithinBoundary(Instructions insts,
+                         DeadEndBlocks *deadEndBlocks) const {
+    assert(asImpl().isInitialized());
+
+    for (auto *inst : insts) {
+      if (!isWithinBoundary(inst, deadEndBlocks))
+        return false;
+    }
+    return true;
+  };
+
   /// Returns true when all \p uses are between this def and the liveness
   /// boundary \p deadEndBlocks is optional.
   bool areUsesWithinBoundary(ArrayRef<Operand *> uses,
diff --git a/include/swift/SIL/SILBasicBlock.h b/include/swift/SIL/SILBasicBlock.h
index 877e144234baf..6a5f691ccf68a 100644
--- a/include/swift/SIL/SILBasicBlock.h
+++ b/include/swift/SIL/SILBasicBlock.h
@@ -368,8 +368,6 @@ public SwiftObjectHeader {
   const SILArgument *getArgument(unsigned i) const { return ArgumentList[i]; }
   SILArgument *getArgument(unsigned i) { return ArgumentList[i]; }
 
-  void cloneArgumentList(SILBasicBlock *Other);
-
   void moveArgumentList(SILBasicBlock *from);
 
   /// Erase a specific argument from the arg list.
diff --git a/include/swift/SIL/SILBitfield.h b/include/swift/SIL/SILBitfield.h
index ee46097540747..a3497f554941a 100644
--- a/include/swift/SIL/SILBitfield.h
+++ b/include/swift/SIL/SILBitfield.h
@@ -111,7 +111,7 @@ template <class Impl, class T> class SILBitfield {
   }
 };
 
-/// A set which knowns its size.
+/// A set which knows its size.
 ///
 /// This template adds a size property to a base `Set`.
 template <class Set>
diff --git a/include/swift/SIL/SILBridging.h b/include/swift/SIL/SILBridging.h
index a127562484a9b..a4613c8143b86 100644
--- a/include/swift/SIL/SILBridging.h
+++ b/include/swift/SIL/SILBridging.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -13,16 +13,13 @@
 #ifndef SWIFT_SIL_SILBRIDGING_H
 #define SWIFT_SIL_SILBRIDGING_H
 
-// Do not add other C++/llvm/swift header files here!
-// Function implementations should be placed into SILBridgingImpl.h or SILBridging.cpp and
-// required header files should be added there.
-//
-// Pure bridging mode does not permit including any C++/llvm/swift headers.
-// See also the comments for `BRIDGING_MODE` in the top-level CMakeLists.txt file.
-//
+/// `SILBridging.h` is imported into Swift. Be *very* careful with what you
+/// include here and keep these includes minimal!
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
 #include "swift/AST/ASTBridging.h"
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 #include "llvm/ADT/ArrayRef.h"
 #include "swift/SIL/SILInstruction.h"
 #include "swift/SIL/SILWitnessTable.h"
@@ -39,8 +36,10 @@ struct BridgedBasicBlock;
 struct BridgedSuccessorArray;
 struct OptionalBridgedBasicBlock;
 struct BridgedDeclRef;
+struct BridgedContext;
 
 namespace swift {
+class SILContext;
 class ValueBase;
 class Operand;
 struct SILDebugVariable;
@@ -61,10 +60,13 @@ class SymbolicValueBumpAllocator;
 class ConstExprEvaluator;
 class SILWitnessTable;
 class SILDefaultWitnessTable;
+class SILLoopInfo;
+class SILLoop;
+class BridgedClonerImpl;
+class BridgedTypeSubstClonerImpl;
 class SILDebugLocation;
 class NominalTypeDecl;
 class VarDecl;
-class SwiftPassInvocation;
 class GenericSpecializationInformation;
 class LifetimeDependenceInfo;
 class IndexSubset;
@@ -74,8 +76,28 @@ class SILParameterInfo;
 struct SILDeclRef;
 class SILBuilder;
 class SILLocation;
+class BasicBlockSet;
+class NodeSet;
+class OperandSet;
+class FixedSizeSlabPayload;
+class FixedSizeSlab;
 }
 
+struct BridgedLoop {
+  swift::SILLoop * _Nonnull l;
+  
+  BRIDGED_INLINE SwiftInt getInnerLoopCount() const;
+  BRIDGED_INLINE BridgedLoop getInnerLoop(SwiftInt index) const;
+  
+  BRIDGED_INLINE SwiftInt getBasicBlockCount() const;
+  BRIDGED_INLINE BridgedBasicBlock getBasicBlock(SwiftInt index) const;
+  
+  BRIDGED_INLINE OptionalBridgedBasicBlock getPreheader() const;
+  BRIDGED_INLINE BridgedBasicBlock getHeader() const;
+  
+  BRIDGED_INLINE bool contains(BridgedBasicBlock block) const;
+};
+
 bool swiftModulesInitialized();
 void registerBridgedClass(BridgedStringRef className, SwiftMetatype metatype);
 
@@ -85,7 +107,9 @@ enum class BridgedResultConvention {
   Unowned,
   UnownedInnerPointer,
   Autoreleased,
-  Pack
+  Pack,
+  GuaranteedAddress,
+  Guaranteed,
 };
 
 struct BridgedResultInfo {
@@ -219,8 +243,6 @@ BridgedParameterInfoArray SILFunctionType_getParameters(BridgedCanType);
 
 BRIDGED_INLINE bool SILFunctionType_hasSelfParam(BridgedCanType);
 
-BRIDGED_INLINE bool SILFunctionType_isTrivialNoescape(BridgedCanType);
-
 SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
 BridgedYieldInfoArray SILFunctionType_getYields(BridgedCanType);
 
@@ -248,7 +270,6 @@ struct BridgedType {
   BRIDGED_INLINE bool isAddress() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getAddressType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getObjectType() const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDiagnosticArgument asDiagnosticArgument() const;
   BRIDGED_INLINE bool isTrivial(BridgedFunction f) const;
   BRIDGED_INLINE bool isNonTrivialOrContainsRawPointer(BridgedFunction f) const;
   BRIDGED_INLINE bool isLoadable(BridgedFunction f) const;
@@ -260,7 +281,13 @@ struct BridgedType {
   BRIDGED_INLINE bool isExactSuperclassOf(BridgedType t) const;
   BRIDGED_INLINE bool isMarkedAsImmortal() const;
   BRIDGED_INLINE bool isAddressableForDeps(BridgedFunction f) const;
+  BRIDGED_INLINE SWIFT_IMPORT_UNSAFE BridgedASTType getRawLayoutSubstitutedLikeType() const;
+  BRIDGED_INLINE SWIFT_IMPORT_UNSAFE BridgedASTType getRawLayoutSubstitutedCountType() const;
   BRIDGED_INLINE SwiftInt getCaseIdxOfEnumType(BridgedStringRef name) const;
+  static BRIDGED_INLINE SwiftInt getNumBoxFields(BridgedCanType boxTy);
+  static SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getBoxFieldType(BridgedCanType boxTy,
+                                                                        SwiftInt idx, BridgedFunction f);
+  static BRIDGED_INLINE bool getBoxFieldIsMutable(BridgedCanType boxTy, SwiftInt idx);
   BRIDGED_INLINE SwiftInt getNumNominalFields() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getFieldType(SwiftInt idx, BridgedFunction f) const;
   BRIDGED_INLINE SwiftInt getFieldIdxOfNominalType(BridgedStringRef name) const;
@@ -326,7 +353,7 @@ struct BridgedValueArray {
   const BridgeValueExistential * _Nullable base;
   size_t count;
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
   llvm::ArrayRef<swift::SILValue> getValues(llvm::SmallVectorImpl<swift::SILValue> &storage);
 #endif
 };
@@ -390,17 +417,28 @@ enum class BridgedMemoryBehavior {
 struct BridgedLocation {
   uint64_t storage[3];
 
+  struct FilenameAndLocation {
+    BridgedStringRef path;
+    SwiftInt line;
+    SwiftInt column;
+  };
+
   BRIDGED_INLINE BridgedLocation(const swift::SILDebugLocation &loc);
   BRIDGED_INLINE const swift::SILDebugLocation &getLoc() const;
 
   BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedLocation getAutogeneratedLocation() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedLocation getCleanupLocation() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedLocation withScopeOf(BridgedLocation other) const;
   BRIDGED_INLINE bool hasValidLineNumber() const;
   BRIDGED_INLINE bool isAutoGenerated() const;
   BRIDGED_INLINE bool isInlined() const;
   BRIDGED_INLINE bool isEqualTo(BridgedLocation rhs) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSourceLoc getSourceLocation() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE swift::SourceLoc getSourceLocation() const;
+  BRIDGED_INLINE bool isFilenameAndLocation() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE FilenameAndLocation getFilenameAndLocation() const;
   BRIDGED_INLINE bool hasSameSourceLocation(BridgedLocation rhs) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDeclObj getDecl() const;
   static BRIDGED_INLINE BridgedLocation fromNominalTypeDecl(BridgedDeclObj decl);
   static BRIDGED_INLINE BridgedLocation getArtificialUnreachableLocation();
 };
@@ -423,15 +461,21 @@ struct BridgedFunction {
     NoLocks = 2,
     NoRuntime = 3,
     NoExistentials = 4,
-    NoObjCBridging = 5
+    NoObjCBridging = 5,
+    ManualOwnership = 6,
   };
 
   enum class InlineStrategy {
     InlineDefault,
     NoInline,
+    HeuristicAlwaysInline,
     AlwaysInline
   };
 
+  enum class ABILanguage {
+    Swift, C
+  };
+
   enum class ThunkKind {
     IsNotThunk,
     IsThunk,
@@ -462,8 +506,14 @@ struct BridgedFunction {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef getName() const;
   BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedLocation getLocation() const;
+  BRIDGED_INLINE bool isAccessor() const;
+  BRIDGED_INLINE bool isInitializer() const;
+  BRIDGED_INLINE bool isDeinitializer() const;
+  BRIDGED_INLINE bool isImplicit() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef getAccessorName() const;
   BRIDGED_INLINE bool hasOwnership() const;
   BRIDGED_INLINE bool hasLoweredAddresses() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType getLoweredFunctionType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType getLoweredFunctionTypeInContext() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedGenericSignature getGenericSignature() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSubstitutionMap getForwardingSubstitutionMap() const;
@@ -490,14 +540,15 @@ struct BridgedFunction {
   BRIDGED_INLINE EffectsKind getEffectAttribute() const;
   BRIDGED_INLINE PerformanceConstraints getPerformanceConstraints() const;
   BRIDGED_INLINE InlineStrategy getInlineStrategy() const;
-  BRIDGED_INLINE bool isSerialized() const;
-  BRIDGED_INLINE bool isAnySerialized() const;
+  BRIDGED_INLINE ABILanguage getSILFunctionLanguage() const;
   BRIDGED_INLINE SerializedKind getSerializedKind() const;
   BRIDGED_INLINE bool canBeInlinedIntoCaller(SerializedKind) const;
   BRIDGED_INLINE bool hasValidLinkageForFragileRef(SerializedKind) const;
   BRIDGED_INLINE ThunkKind isThunk() const;
   BRIDGED_INLINE void setThunk(ThunkKind) const;
   BRIDGED_INLINE bool needsStackProtection() const;
+  BRIDGED_INLINE bool shouldOptimize() const;
+  BRIDGED_INLINE bool isReferencedInModule() const;
   BRIDGED_INLINE bool wasDeserializedCanonical() const;
   BRIDGED_INLINE void setNeedStackProtection(bool needSP) const;
   BRIDGED_INLINE void setIsPerformanceConstraint(bool isPerfConstraint) const;
@@ -507,11 +558,14 @@ struct BridgedFunction {
   BRIDGED_INLINE BridgedLinkage getLinkage() const;
   BRIDGED_INLINE void setLinkage(BridgedLinkage linkage) const;
   BRIDGED_INLINE void setIsSerialized(bool isSerialized) const;
+  BRIDGED_INLINE bool conformanceMatchesActorIsolation(BridgedConformance conformance) const;
+  BRIDGED_INLINE bool isSpecialization() const;
   bool isTrapNoReturn() const;
   bool isConvertPointerToPointerArgument() const;
   bool isAutodiffVJP() const;
   SwiftInt specializationLevel() const;
-  SWIFT_IMPORT_UNSAFE BridgedSubstitutionMap getMethodSubstitutions(BridgedSubstitutionMap contextSubs) const;
+  SWIFT_IMPORT_UNSAFE BridgedSubstitutionMap getMethodSubstitutions(BridgedSubstitutionMap contextSubs,
+                                                                    BridgedCanType selfType) const;
   BRIDGED_INLINE OptionalSourceFileKind getSourceFileKind() const;
 
   enum class ParseEffectsMode {
@@ -543,6 +597,7 @@ struct BridgedFunction {
   typedef EffectInfo (* _Nonnull GetEffectInfoFn)(BridgedFunction, SwiftInt);
   typedef BridgedMemoryBehavior (* _Nonnull GetMemBehaviorFn)(BridgedFunction, bool);
   typedef bool (* _Nonnull ArgumentMayReadFn)(BridgedFunction, BridgedOperand, BridgedValue);
+  typedef bool (* _Nonnull IsDeinitBarrierFn)(BridgedFunction);
 
   static void registerBridging(SwiftMetatype metatype,
               RegisterFn initFn, RegisterFn destroyFn,
@@ -550,7 +605,8 @@ struct BridgedFunction {
               CopyEffectsFn copyEffectsFn,
               GetEffectInfoFn effectInfoFn,
               GetMemBehaviorFn memBehaviorFn,
-              ArgumentMayReadFn argumentMayReadFn);
+              ArgumentMayReadFn argumentMayReadFn,
+              IsDeinitBarrierFn isDeinitBarrierFn);
 };
 
 struct OptionalBridgedFunction {
@@ -569,8 +625,11 @@ struct BridgedGlobalVar {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef getName() const;
   BRIDGED_INLINE bool isLet() const;
   BRIDGED_INLINE void setLet(bool value) const;
+  BRIDGED_INLINE bool markedAsUsed() const;
+  BRIDGED_INLINE void setMarkedAsUsed(bool value) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getType() const;
   BRIDGED_INLINE BridgedLinkage getLinkage() const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSourceLoc getSourceLocation() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE swift::SourceLoc getSourceLocation() const;
   BRIDGED_INLINE bool isPossiblyUsedExternally() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedInstruction getFirstStaticInitInst() const;
   bool canBeInitializedStatically() const;
@@ -606,6 +665,7 @@ struct BridgedGenericSpecializationInformation {
 struct BridgedSILDebugVariable {
   uint64_t storage[16];
 
+  BRIDGED_INLINE BridgedSILDebugVariable() {}
   BRIDGED_INLINE BridgedSILDebugVariable(const swift::SILDebugVariable &var);
   BRIDGED_INLINE BridgedSILDebugVariable(const BridgedSILDebugVariable &rhs);
   BRIDGED_INLINE ~BridgedSILDebugVariable();
@@ -616,7 +676,7 @@ struct BridgedSILDebugVariable {
 struct BridgedInstruction {
   SwiftObject obj;
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
   template <class I> I *_Nonnull getAs() const {
     return llvm::cast<I>(static_cast<swift::SILNode *>(obj)->castToInstruction());
   }
@@ -646,6 +706,7 @@ struct BridgedInstruction {
   bool maySynchronize() const;
   bool mayBeDeinitBarrierNotConsideringSideEffects() const;
   BRIDGED_INLINE bool shouldBeForwarding() const;
+  BRIDGED_INLINE bool isIdenticalTo(BridgedInstruction inst) const;
 
   // =========================================================================//
   //                   Generalized instruction subclasses
@@ -681,11 +742,6 @@ struct BridgedInstruction {
     unknown
   };
 
-  struct OptionalInt {
-    SwiftInt value;
-    bool hasValue;
-  };
-
   enum class MarkDependenceKind {
     Unresolved, Escaping, NonEscaping
   };
@@ -702,9 +758,8 @@ struct BridgedInstruction {
     CopyOnSuccess
   };
 
-  enum class CastingIsolatedConformances {
-    Allow,
-    Prohibit
+  struct CheckedCastInstOptions {
+    uint8_t storage;
   };
 
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef CondFailInst_getMessage() const;
@@ -722,10 +777,11 @@ struct BridgedInstruction {
   BRIDGED_INLINE bool IndexAddrInst_needsStackProtection() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedConformanceArray InitExistentialRefInst_getConformances() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType InitExistentialRefInst_getFormalConcreteType() const;
+  BRIDGED_INLINE bool OpenExistentialAddr_isImmutable() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedGlobalVar GlobalAccessInst_getGlobal() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedGlobalVar AllocGlobalInst_getGlobal() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedFunction FunctionRefBaseInst_getReferencedFunction() const;
-  BRIDGED_INLINE OptionalInt IntegerLiteralInst_getValue() const;
+  BRIDGED_INLINE BridgedOptionalInt IntegerLiteralInst_getValue() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef StringLiteralInst_getValue() const;
   BRIDGED_INLINE int StringLiteralInst_getEncoding() const;
   BRIDGED_INLINE SwiftInt TupleExtractInst_fieldIndex() const;
@@ -748,6 +804,7 @@ struct BridgedInstruction {
   BRIDGED_INLINE SwiftInt InitEnumDataAddrInst_caseIndex() const;
   BRIDGED_INLINE SwiftInt UncheckedTakeEnumDataAddrInst_caseIndex() const;
   BRIDGED_INLINE SwiftInt InjectEnumAddrInst_caseIndex() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj InjectEnumAddrInst_element() const;
   BRIDGED_INLINE SwiftInt RefElementAddrInst_fieldIndex() const;
   BRIDGED_INLINE bool RefElementAddrInst_fieldIsLet() const;
   BRIDGED_INLINE bool RefElementAddrInst_isImmutable() const;
@@ -760,6 +817,8 @@ struct BridgedInstruction {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedGenericSpecializationInformation ApplyInst_getSpecializationInfo() const;
   BRIDGED_INLINE bool TryApplyInst_getNonAsync() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedGenericSpecializationInformation TryApplyInst_getSpecializationInfo() const;
+  BRIDGED_INLINE bool BeginApplyInst_getNonThrowing() const;
+  BRIDGED_INLINE bool BeginApplyInst_getNonAsync() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclRef ClassMethodInst_getMember() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclRef WitnessMethodInst_getMember() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType WitnessMethodInst_getLookupType() const;
@@ -772,32 +831,42 @@ struct BridgedInstruction {
   BRIDGED_INLINE bool AllocStackInst_hasDynamicLifetime() const;
   BRIDGED_INLINE bool AllocStackInst_isFromVarDecl() const;
   BRIDGED_INLINE bool AllocStackInst_usesMoveableValueDebugInfo() const;
+  BRIDGED_INLINE bool AllocStackInst_isLexical() const;
+  BRIDGED_INLINE bool AllocBoxInst_hasDynamicLifetime() const;
   BRIDGED_INLINE bool AllocRefInstBase_isObjc() const;
   BRIDGED_INLINE bool AllocRefInstBase_canAllocOnStack() const;
   BRIDGED_INLINE SwiftInt AllocRefInstBase_getNumTailTypes() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSILTypeArray AllocRefInstBase_getTailAllocatedTypes() const;
   BRIDGED_INLINE bool AllocRefDynamicInst_isDynamicTypeDeinitAndSizeKnownEquivalentToBaseType() const;
   BRIDGED_INLINE SwiftInt BeginApplyInst_numArguments() const;
+  BRIDGED_INLINE bool BeginApplyInst_isCalleeAllocated() const;
   BRIDGED_INLINE SwiftInt TryApplyInst_numArguments() const;
+  BRIDGED_INLINE BridgedArgumentConvention YieldInst_getConvention(BridgedOperand forOperand) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock BranchInst_getTargetBlock() const;
   BRIDGED_INLINE SwiftInt SwitchEnumInst_getNumCases() const;
   BRIDGED_INLINE SwiftInt SwitchEnumInst_getCaseIndex(SwiftInt idx) const;
   BRIDGED_INLINE SwiftInt StoreInst_getStoreOwnership() const;
   BRIDGED_INLINE SwiftInt AssignInst_getAssignOwnership() const;
   BRIDGED_INLINE MarkDependenceKind MarkDependenceInst_dependenceKind() const;
-  BRIDGED_INLINE void MarkDependenceInst_resolveToNonEscaping() const;
-  BRIDGED_INLINE void MarkDependenceInst_settleToEscaping() const;
+  BRIDGED_INLINE void MarkDependenceInstruction_resolveToNonEscaping() const;
+  BRIDGED_INLINE void MarkDependenceInstruction_settleToEscaping() const;
   BRIDGED_INLINE MarkDependenceKind MarkDependenceAddrInst_dependenceKind() const;
-  BRIDGED_INLINE void MarkDependenceAddrInst_resolveToNonEscaping() const;
-  BRIDGED_INLINE void MarkDependenceAddrInst_settleToEscaping() const;
   BRIDGED_INLINE SwiftInt BeginAccessInst_getAccessKind() const;
   BRIDGED_INLINE bool BeginAccessInst_isStatic() const;
   BRIDGED_INLINE bool BeginAccessInst_isUnsafe() const;
+  BRIDGED_INLINE void BeginAccess_setAccessKind(SwiftInt accessKind) const;
+  BRIDGED_INLINE SwiftInt BeginAccessInst_getEnforcement() const;
+  BRIDGED_INLINE void BeginAccess_setEnforcement(SwiftInt accessKind) const;
   BRIDGED_INLINE bool CopyAddrInst_isTakeOfSrc() const;
   BRIDGED_INLINE bool CopyAddrInst_isInitializationOfDest() const;
+  BRIDGED_INLINE void CopyAddrInst_setIsTakeOfSrc(bool isTakeOfSrc) const;
+  BRIDGED_INLINE void CopyAddrInst_setIsInitializationOfDest(bool isInitializationOfDest) const;
+  BRIDGED_INLINE bool DeallocBoxInst_isDeadEnd() const;
   BRIDGED_INLINE bool ExplicitCopyAddrInst_isTakeOfSrc() const;
   BRIDGED_INLINE bool ExplicitCopyAddrInst_isInitializationOfDest() const;
   BRIDGED_INLINE SwiftInt MarkUninitializedInst_getKind() const;
+  BRIDGED_INLINE SwiftInt MarkUnresolvedNonCopyableValue_getCheckKind() const;
+  BRIDGED_INLINE bool MarkUnresolvedNonCopyableValue_isStrict() const;
   BRIDGED_INLINE void RefCountingInst_setIsAtomic(bool isAtomic) const;
   BRIDGED_INLINE bool RefCountingInst_getIsAtomic() const;
   BRIDGED_INLINE SwiftInt CondBranchInst_getNumTrueArgs() const;
@@ -805,6 +874,8 @@ struct BridgedInstruction {
   BRIDGED_INLINE bool AllocRefInst_isBare() const;
   BRIDGED_INLINE void AllocRefInst_setIsBare() const;
   BRIDGED_INLINE void TermInst_replaceBranchTarget(BridgedBasicBlock from, BridgedBasicBlock to) const;
+  BRIDGED_INLINE BridgedSubstitutionMap KeyPathInst_getSubstitutionMap() const;
+  BRIDGED_INLINE bool KeyPathInst_hasPattern() const;
   BRIDGED_INLINE SwiftInt KeyPathInst_getNumComponents() const;
   BRIDGED_INLINE void KeyPathInst_getReferencedFunctions(SwiftInt componentIdx, KeyPathFunctionResults * _Nonnull results) const;
   BRIDGED_INLINE void GlobalAddrInst_clearToken() const;
@@ -813,22 +884,22 @@ struct BridgedInstruction {
   BRIDGED_INLINE void LoadInst_setOwnership(SwiftInt ownership) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType UnconditionalCheckedCast_getSourceFormalType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType UnconditionalCheckedCast_getTargetFormalType() const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE CastingIsolatedConformances
-      UnconditionalCheckedCast_getIsolatedConformances() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE CheckedCastInstOptions
+      UnconditionalCheckedCast_getCheckedCastOptions() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType UnconditionalCheckedCastAddr_getSourceFormalType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType UnconditionalCheckedCastAddr_getTargetFormalType() const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE CastingIsolatedConformances
-      UnconditionalCheckedCastAddr_getIsolatedConformances() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE CheckedCastInstOptions
+      UnconditionalCheckedCastAddr_getCheckedCastOptions() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock CheckedCastBranch_getSuccessBlock() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock CheckedCastBranch_getFailureBlock() const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE CastingIsolatedConformances
-      CheckedCastBranch_getIsolatedConformances() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE CheckedCastInstOptions
+      CheckedCastBranch_getCheckedCastOptions() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType CheckedCastAddrBranch_getSourceFormalType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType CheckedCastAddrBranch_getTargetFormalType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock CheckedCastAddrBranch_getSuccessBlock() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock CheckedCastAddrBranch_getFailureBlock() const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE CastingIsolatedConformances
-      CheckedCastAddrBranch_getIsolatedConformances() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE CheckedCastInstOptions
+      CheckedCastAddrBranch_getCheckedCastOptions() const;
   BRIDGED_INLINE void CheckedCastBranch_updateSourceFormalTypeFromOperandLoweredType() const;
   BRIDGED_INLINE CastConsumptionKind CheckedCastAddrBranch_getConsumptionKind() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSubstitutionMap ApplySite_getSubstitutionMap() const;
@@ -838,7 +909,6 @@ struct BridgedInstruction {
   BRIDGED_INLINE SwiftInt FullApplySite_numIndirectResultArguments() const;
   BRIDGED_INLINE bool ConvertFunctionInst_withoutActuallyEscaping() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType TypeValueInst_getParamType() const;
-  BRIDGED_INLINE SwiftInt TypeValueInst_getValue() const;
 
   // =========================================================================//
   //                   VarDeclInst and DebugVariableInst
@@ -885,8 +955,9 @@ struct BridgedArgument {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock getParent() const;
   BRIDGED_INLINE bool isReborrow() const;
   BRIDGED_INLINE bool FunctionArgument_isLexical() const;
+  BRIDGED_INLINE bool FunctionArgument_isClosureCapture() const;
   BRIDGED_INLINE void setReborrow(bool reborrow) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDeclObj getVarDecl() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDeclObj getDecl() const;
   BRIDGED_INLINE void copyFlags(BridgedArgument fromArgument) const;
 };
 
@@ -919,8 +990,11 @@ struct BridgedBasicBlock {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedInstruction getLastInst() const;
   BRIDGED_INLINE SwiftInt getNumArguments() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedArgument getArgument(SwiftInt index) const;
-  SWIFT_IMPORT_UNSAFE  BRIDGED_INLINE BridgedArgument addBlockArgument(BridgedType type, BridgedValue::Ownership ownership) const;
-  SWIFT_IMPORT_UNSAFE  BRIDGED_INLINE BridgedArgument addFunctionArgument(BridgedType type) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedArgument addBlockArgument(BridgedType type, BridgedValue::Ownership ownership) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedArgument addFunctionArgument(BridgedType type) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedArgument insertFunctionArgument(SwiftInt atPosition, BridgedType type,
+                                                                            BridgedValue::Ownership ownership,
+                                                                            OptionalBridgedDeclObj decl) const;
   BRIDGED_INLINE void eraseArgument(SwiftInt index) const;
   BRIDGED_INLINE void moveAllInstructionsToBegin(BridgedBasicBlock dest) const;
   BRIDGED_INLINE void moveAllInstructionsToEnd(BridgedBasicBlock dest) const;
@@ -1040,7 +1114,7 @@ struct BridgedWitnessTableEntry {
     baseProtocol
   };
 
-#ifdef USED_IN_CPP_SOURCE
+#ifdef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
   static BridgedWitnessTableEntry bridge(const swift::SILWitnessTable::Entry &entry) {
     BridgedWitnessTableEntry bridgedEntry;
     *reinterpret_cast<swift::SILWitnessTable::Entry *>(&bridgedEntry.storage) = entry;
@@ -1059,7 +1133,6 @@ struct BridgedWitnessTableEntry {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj getAssociatedTypeRequirement() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType getAssociatedTypeWitness() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType getAssociatedConformanceRequirement() const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedCanType getAssociatedConformanceSubstType() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedConformance getAssociatedConformanceWitness() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj getBaseProtocolRequirement() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedConformance getBaseProtocolWitness() const;
@@ -1074,7 +1147,6 @@ struct BridgedWitnessTableEntry {
                                                        BridgedCanType witness);
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
   static BridgedWitnessTableEntry createAssociatedConformance(BridgedCanType requirement,
-                                                              BridgedCanType substType,
                                                               BridgedConformance witness);
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
   static BridgedWitnessTableEntry createBaseProtocol(BridgedDeclObj requirement,
@@ -1088,6 +1160,7 @@ struct BridgedWitnessTable {
   BRIDGED_INLINE SwiftInt getNumEntries() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedWitnessTableEntry getEntry(SwiftInt index) const;
   BRIDGED_INLINE bool isDeclaration() const;
+  BRIDGED_INLINE bool isSpecialized() const;
 };
 
 struct OptionalBridgedWitnessTable {
@@ -1117,6 +1190,7 @@ struct BridgedBuilder{
 
   BRIDGED_INLINE swift::SILBuilder unbridged() const;
   BRIDGED_INLINE swift::SILLocation regularLoc() const;
+  BRIDGED_INLINE swift::SILLocation returnLoc() const;
 
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createBuiltin(BridgedStringRef name,
                                                                       BridgedType type,
@@ -1127,15 +1201,18 @@ struct BridgedBuilder{
                                           BridgedValueArray arguments) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createCondFail(BridgedValue condition,
                                                                        BridgedStringRef message) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createIntegerLiteral(BridgedType type, SwiftInt value) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createIntegerLiteral(
+      BridgedType type, SwiftInt value, bool treatAsSigned) const;
 
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createAllocRef(BridgedType type,
     bool objc, bool canAllocOnStack, bool isBare,
     BridgedSILTypeArray elementTypes, BridgedValueArray elementCountOperands) const;
 
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction
-  createAllocStack(BridgedType type, bool hasDynamicLifetime, bool isLexical,
-                   bool isFromVarDecl, bool wasMoved) const;
+  createAllocStack(BridgedType type, BridgedSILDebugVariable debugVar,
+                   bool hasDynamicLifetime, bool isLexical, bool isFromVarDecl, bool wasMoved) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction
+  createAllocStack(BridgedType type, bool hasDynamicLifetime, bool isLexical, bool isFromVarDecl, bool wasMoved) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createAllocVector(BridgedValue capacity,
                                                                           BridgedType type) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createDeallocStack(BridgedValue operand) const;
@@ -1155,17 +1232,21 @@ struct BridgedBuilder{
                                                                                BridgedType type) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createUncheckedAddrCast(BridgedValue op,
                                                                                 BridgedType type) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createUncheckedValueCast(BridgedValue op,
+                                                                                 BridgedType type) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createUpcast(BridgedValue op, BridgedType type) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createCheckedCastAddrBranch(
       BridgedValue source, BridgedCanType sourceFormalType,
       BridgedValue destination, BridgedCanType targetFormalType,
-      BridgedInstruction::CastingIsolatedConformances isolatedConformances,
+      BridgedInstruction::CheckedCastInstOptions options,
       BridgedInstruction::CastConsumptionKind consumptionKind,
       BridgedBasicBlock successBlock, BridgedBasicBlock failureBlock) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createUnconditionalCheckedCastAddr(
-        BridgedInstruction::CastingIsolatedConformances isolatedConformances,
+        BridgedInstruction::CheckedCastInstOptions options,
         BridgedValue source, BridgedCanType sourceFormalType,
         BridgedValue destination, BridgedCanType targetFormalType) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createUncheckedOwnershipConversion(
+        BridgedValue op, BridgedValue::Ownership ownership) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createLoad(BridgedValue op, SwiftInt ownership) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createLoadBorrow(BridgedValue op) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createBeginDeallocRef(BridgedValue reference,
@@ -1206,6 +1287,10 @@ struct BridgedBuilder{
                                           BridgedBasicBlock normalBB, BridgedBasicBlock errorBB,
                                           bool isNonAsync,
                                           BridgedGenericSpecializationInformation specInfo) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createBeginApply(BridgedValue function,
+                                          BridgedSubstitutionMap subMap,
+                                          BridgedValueArray arguments, bool isNonThrowing, bool isNonAsync,
+                                          BridgedGenericSpecializationInformation specInfo) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createWitnessMethod(BridgedCanType lookupType,
                                           BridgedConformance conformance,
                                           BridgedDeclRef member, BridgedType methodType) const;
@@ -1233,13 +1318,17 @@ struct BridgedBuilder{
                                                                            BridgedArgumentConvention calleeConvention,
                                                                            BridgedSubstitutionMap bridgedSubstitutionMap = BridgedSubstitutionMap(),
                                                                            bool hasUnknownIsolation = true,
-                                                                           bool isOnStack = false) const;                                                                                  
+                                                                           bool isOnStack = false) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createBranch(BridgedBasicBlock destBlock,
                                                                      BridgedValueArray arguments) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createCondBranch(BridgedValue condition,
+                                                                         BridgedBasicBlock trueBlock,
+                                                                         BridgedBasicBlock falseBlock) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createUnreachable() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createObject(BridgedType type, BridgedValueArray arguments,
                                                                      SwiftInt numBaseElements) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createVector(BridgedValueArray arguments) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createVectorBaseAddr(BridgedValue vector) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createGlobalAddr(BridgedGlobalVar global,
                                                                          OptionalBridgedValue dependencyToken) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createGlobalValue(BridgedGlobalVar global,
@@ -1258,6 +1347,7 @@ struct BridgedBuilder{
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createTupleElementAddr(BridgedValue addr,
                                                                                SwiftInt elementIndex) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createDestructureTuple(BridgedValue str) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createProjectBox(BridgedValue box, SwiftInt fieldIdx) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createStore(BridgedValue src, BridgedValue dst,
                                           SwiftInt ownership) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createInitExistentialRef(BridgedValue instance,
@@ -1271,12 +1361,19 @@ struct BridgedBuilder{
                                           BridgedASTType::MetatypeRepresentation representation) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createEndCOWMutation(BridgedValue instance,
                                                                              bool keepUnique) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createEndCOWMutationAddr(BridgedValue instance) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createMarkDependence(
     BridgedValue value, BridgedValue base, BridgedInstruction::MarkDependenceKind dependenceKind) const;
 
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createMarkDependenceAddr(
     BridgedValue value, BridgedValue base, BridgedInstruction::MarkDependenceKind dependenceKind) const;
     
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createMarkUninitialized(
+    BridgedValue value, SwiftInt kind) const;
+
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createMarkUnresolvedNonCopyableValue(
+    BridgedValue value, SwiftInt checkKind, bool isStrict) const;
+
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createEndAccess(BridgedValue value) const;
 
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createEndApply(BridgedValue value) const;
@@ -1289,24 +1386,201 @@ struct BridgedBuilder{
   SWIFT_IMPORT_UNSAFE void destroyCapturedArgs(BridgedInstruction partialApply) const;
 };
 
-// Passmanager and Context
+// Context
 
-namespace swift {
-  class SwiftPassInvocation;
-}
+struct BridgedBasicBlockSet {
+  swift::BasicBlockSet * _Nonnull set;
 
-struct BridgedChangeNotificationHandler {
-  swift::SwiftPassInvocation * _Nonnull invocation;
+  BRIDGED_INLINE bool contains(BridgedBasicBlock block) const;
+  BRIDGED_INLINE bool insert(BridgedBasicBlock block) const;
+  BRIDGED_INLINE void erase(BridgedBasicBlock block) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedFunction getFunction() const;
+};
 
-  enum class Kind {
-    instructionsChanged,
-    callsChanged,
-    branchesChanged,
-    effectsChanged,
-    functionTablesChanged
+struct BridgedNodeSet {
+  swift::NodeSet * _Nonnull set;
+
+  BRIDGED_INLINE bool containsValue(BridgedValue value) const;
+  BRIDGED_INLINE bool insertValue(BridgedValue value) const;
+  BRIDGED_INLINE void eraseValue(BridgedValue value) const;
+  BRIDGED_INLINE bool containsInstruction(BridgedInstruction inst) const;
+  BRIDGED_INLINE bool insertInstruction(BridgedInstruction inst) const;
+  BRIDGED_INLINE void eraseInstruction(BridgedInstruction inst) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedFunction getFunction() const;
+};
+
+struct BridgedOperandSet {
+  swift::OperandSet * _Nonnull set;
+
+  BRIDGED_INLINE bool contains(BridgedOperand operand) const;
+  BRIDGED_INLINE bool insert(BridgedOperand operand) const;
+  BRIDGED_INLINE void erase(BridgedOperand operand) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedFunction getFunction() const;
+};
+
+struct BridgedContext {
+  swift::SILContext * _Nonnull context;
+
+  enum class SILStage {
+    Raw,
+    Canonical,
+    Lowered
+  };
+
+  enum class NotificationKind {
+    Instructions = 0x1,
+    Calls = 0x2,
+    Branches = 0x4,
+    Effects = 0x8,
+    FunctionTables = 0x10
+  };
+
+  BRIDGED_INLINE bool isTransforming(BridgedFunction function) const;
+  BRIDGED_INLINE void notifyChanges(NotificationKind changeKind) const;
+
+  // Module
+
+  BridgedOwnedString getModuleDescription() const;
+  BRIDGED_INLINE SILStage getSILStage() const;
+  BRIDGED_INLINE bool moduleIsSerialized() const;
+  BRIDGED_INLINE bool moduleHasLoweredAddresses() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj getCurrentModuleContext() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedFunction lookupFunction(BridgedStringRef name) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedVTable lookupVTable(BridgedDeclObj classDecl) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedVTable lookupSpecializedVTable(BridgedType classType) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE void loadFunction(BridgedFunction function, bool loadCalleesRecursively) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedFunction loadFunction(BridgedStringRef name,
+                                                                          bool loadCalleesRecursively) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedFunction lookupStdlibFunction(BridgedStringRef name) const;
+  SWIFT_IMPORT_UNSAFE OptionalBridgedFunction lookUpNominalDeinitFunction(BridgedDeclObj nominal) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSubstitutionMap getContextSubstitutionMap(BridgedType type) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getBuiltinIntegerType(SwiftInt bitWidth) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType getTupleType(BridgedArrayRef elementTypes) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj getSwiftArrayDecl() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj getSwiftMutableSpanDecl() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedValue getSILUndef(BridgedType type) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
+  BridgedConformance getSpecializedConformance(BridgedConformance genericConformance,
+                                                       BridgedASTType type,
+                                                       BridgedSubstitutionMap substitutions) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
+  OptionalBridgedWitnessTable lookupWitnessTable(BridgedConformance conformance) const;
+  BRIDGED_INLINE bool calleesAreStaticallyKnowable(BridgedDeclRef method) const;
+
+
+  // Modifying the Module
+
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedWitnessTable createSpecializedWitnessTable(BridgedLinkage linkage,
+                                                                            bool serialized,
+                                                                            BridgedConformance conformance,
+                                                                            BridgedArrayRef bridgedEntries) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedVTable createSpecializedVTable(BridgedType classType,
+                                                                           bool serialized,
+                                                                           BridgedArrayRef bridgedEntries) const;
+  SWIFT_IMPORT_UNSAFE BridgedFunction createEmptyFunction(BridgedStringRef name,
+                                                          const BridgedParameterInfo * _Nullable bridgedParams,
+                                                          SwiftInt paramCount,
+                                                          bool hasSelfParam,
+                                                          BridgedFunction fromFunc) const;
+  SWIFT_IMPORT_UNSAFE BridgedGlobalVar createGlobalVariable(BridgedStringRef name, BridgedType type,
+                                                            BridgedLinkage linkage, bool isLet,
+                                                            bool markedAsUsed) const;
+  void moveFunctionBody(BridgedFunction sourceFunc, BridgedFunction destFunc) const;
+
+  // Function-local SIL modifications
+
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock splitBlockBefore(BridgedInstruction bridgedInst) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock splitBlockAfter(BridgedInstruction bridgedInst) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock createBlockAfter(BridgedBasicBlock bridgedBlock) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock appendBlock(BridgedFunction bridgedFunction) const;
+  BRIDGED_INLINE void eraseInstruction(BridgedInstruction inst, bool salvageDebugInfo) const;
+  BRIDGED_INLINE void eraseBlock(BridgedBasicBlock block) const;
+  static BRIDGED_INLINE void moveInstructionBefore(BridgedInstruction inst, BridgedInstruction beforeInst);
+  static BRIDGED_INLINE void copyInstructionBefore(BridgedInstruction inst, BridgedInstruction beforeInst);
+
+    // SSAUpdater
+
+  BRIDGED_INLINE void SSAUpdater_initialize(BridgedFunction function, BridgedType type,
+                                            BridgedValue::Ownership ownership) const;
+  BRIDGED_INLINE void SSAUpdater_addAvailableValue(BridgedBasicBlock block, BridgedValue value) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedValue SSAUpdater_getValueAtEndOfBlock(BridgedBasicBlock block) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedValue SSAUpdater_getValueInMiddleOfBlock(BridgedBasicBlock block) const;
+  BRIDGED_INLINE SwiftInt SSAUpdater_getNumInsertedPhis() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedValue SSAUpdater_getInsertedPhi(SwiftInt idx) const;
+
+  // Sets
+
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlockSet allocBasicBlockSet() const;
+  BRIDGED_INLINE void freeBasicBlockSet(BridgedBasicBlockSet set) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedNodeSet allocNodeSet() const;
+  BRIDGED_INLINE void freeNodeSet(BridgedNodeSet set) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedOperandSet allocOperandSet() const;
+  BRIDGED_INLINE void freeOperandSet(BridgedOperandSet set) const;
+
+  // Slabs
+
+  struct Slab {
+    swift::FixedSizeSlabPayload * _Nullable data = nullptr;
+
+    BRIDGED_INLINE static SwiftInt getCapacity();
+    BRIDGED_INLINE Slab(swift::FixedSizeSlab * _Nullable slab);
+    BRIDGED_INLINE swift::FixedSizeSlab * _Nullable getSlab() const;
+    SWIFT_IMPORT_UNSAFE BRIDGED_INLINE Slab getNext() const;
+    SWIFT_IMPORT_UNSAFE BRIDGED_INLINE Slab getPrevious() const;
   };
 
-  void notifyChanges(Kind changeKind) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE Slab allocSlab(Slab afterSlab) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE Slab freeSlab(Slab slab) const;
+};
+
+struct BridgedCloner {
+  swift::BridgedClonerImpl * _Nonnull cloner;
+
+  BridgedCloner(BridgedGlobalVar var, BridgedContext context);
+  BridgedCloner(BridgedInstruction inst, BridgedContext context);
+  BridgedCloner(BridgedFunction emptyFunction, BridgedContext context);
+  void destroy(BridgedContext context);
+  SWIFT_IMPORT_UNSAFE BridgedFunction getCloned() const;
+  SWIFT_IMPORT_UNSAFE BridgedBasicBlock getClonedBasicBlock(BridgedBasicBlock originalBasicBlock) const;
+  void cloneFunctionBody(BridgedFunction originalFunction, BridgedBasicBlock clonedEntryBlock,
+                         BridgedValueArray clonedEntryBlockArgs) const;
+  void cloneFunctionBody(BridgedFunction originalFunction) const;
+  SWIFT_IMPORT_UNSAFE BridgedValue getClonedValue(BridgedValue v);
+  bool isValueCloned(BridgedValue v) const;
+  void recordClonedInstruction(BridgedInstruction origInst, BridgedInstruction clonedInst) const;
+  void recordFoldedValue(BridgedValue orig, BridgedValue mapped) const;
+  BridgedInstruction clone(BridgedInstruction inst) const;
+  void setInsertionBlockIfNotSet(BridgedBasicBlock block) const;
+};
+
+struct BridgedTypeSubstCloner {
+  swift::BridgedTypeSubstClonerImpl * _Nonnull cloner;
+
+  BridgedTypeSubstCloner(BridgedFunction fromFunction, BridgedFunction toFunction,
+                         BridgedSubstitutionMap substitutions, BridgedContext context);
+  void destroy(BridgedContext context);
+  void cloneFunctionBody() const;
+  SWIFT_IMPORT_UNSAFE BridgedBasicBlock getClonedBasicBlock(BridgedBasicBlock originalBasicBlock) const;
+  SWIFT_IMPORT_UNSAFE BridgedValue getClonedValue(BridgedValue v);
+};
+
+struct BridgedVerifier {
+  typedef void (* _Nonnull VerifyFunctionFn)(BridgedContext, BridgedFunction);
+
+  static void runSwiftFunctionVerification(swift::SILFunction * _Nonnull f, swift::SILContext * _Nonnull context);
+
+  static void registerVerifier(VerifyFunctionFn verifyFunctionFn);
+  static void verifierError(BridgedStringRef message, OptionalBridgedInstruction atInstruction,
+                            OptionalBridgedArgument atArgument);
+};
+
+struct BridgedUtilities {
+  typedef void (* _Nonnull UpdateFunctionFn)(BridgedContext, BridgedFunction);
+  typedef void (* _Nonnull UpdatePhisFn)(BridgedContext, BridgedArrayRef);
+
+  static void registerPhiUpdater(UpdateFunctionFn updateBorrowedFromFn,
+                                 UpdatePhisFn updateBorrowedFromPhisFn,
+                                 UpdatePhisFn replacePhisWithIncomingValuesFn);
 };
 
 namespace swift::test {
@@ -1333,18 +1607,11 @@ struct BridgedTestArguments {
   SWIFT_IMPORT_UNSAFE BridgedFunction takeFunction() const;
 };
 
-struct BridgedSwiftPassInvocation {
-  swift::SwiftPassInvocation *_Nonnull invocation;
-};
-
 using SwiftNativeFunctionTestThunk =
-    void (*_Nonnull)(void *_Nonnull, BridgedFunction, BridgedTestArguments,
-                     BridgedSwiftPassInvocation);
-
-void registerFunctionTestThunk(SwiftNativeFunctionTestThunk);
+    void (*_Nonnull)(void *_Nonnull, BridgedFunction, BridgedTestArguments, BridgedContext);
 
-void registerFunctionTest(BridgedStringRef,
-                          void *_Nonnull nativeSwiftInvocation);
+void registerTestThunk(SwiftNativeFunctionTestThunk);
+void registerTest(BridgedStringRef, void *_Nonnull nativeSwiftContext);
 
 SWIFT_END_NULLABILITY_ANNOTATIONS
 
diff --git a/include/swift/SIL/SILBridgingImpl.h b/include/swift/SIL/SILBridgingImpl.h
index fd7c8b278b665..79bfb84a6cc66 100644
--- a/include/swift/SIL/SILBridgingImpl.h
+++ b/include/swift/SIL/SILBridgingImpl.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -23,12 +23,15 @@
 #include "swift/AST/Builtins.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/SourceFile.h"
+#include "swift/AST/StorageImpl.h"
 #include "swift/AST/SubstitutionMap.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/BasicBridging.h"
-#include "swift/Basic/Nullability.h"
 #include "swift/SIL/ApplySite.h"
+#include "swift/SIL/CalleeCache.h"
+#include "swift/SIL/DynamicCasts.h"
 #include "swift/SIL/InstWrappers.h"
+#include "swift/SIL/SILContext.h"
 #include "swift/SIL/SILBuilder.h"
 #include "swift/SIL/SILDefaultWitnessTable.h"
 #include "swift/SIL/SILFunctionConventions.h"
@@ -257,10 +260,6 @@ bool SILFunctionType_hasSelfParam(BridgedCanType funcTy) {
   return funcTy.unbridged()->castTo<swift::SILFunctionType>()->hasSelfParam();
 }
 
-bool SILFunctionType_isTrivialNoescape(BridgedCanType funcTy) {
-  return funcTy.unbridged()->castTo<swift::SILFunctionType>()->isTrivialNoEscape();
-}
-
 BridgedYieldInfoArray SILFunctionType_getYields(BridgedCanType funcTy) {
   return {funcTy.unbridged()->castTo<swift::SILFunctionType>()->getYields()};
 }
@@ -330,10 +329,6 @@ BridgedType BridgedType::getObjectType() const {
   return unbridged().getObjectType();
 }
 
-BridgedDiagnosticArgument BridgedType::asDiagnosticArgument() const {
-  return swift::DiagnosticArgument(unbridged().getASTType());
-}
-
 bool BridgedType::isTrivial(BridgedFunction f) const {
   return unbridged().isTrivial(f.getFunction());
 }
@@ -378,10 +373,32 @@ bool BridgedType::isAddressableForDeps(BridgedFunction f) const {
   return unbridged().isAddressableForDeps(*f.getFunction());
 }
 
+BridgedASTType BridgedType::getRawLayoutSubstitutedLikeType() const {
+  return {unbridged().getRawLayoutSubstitutedLikeType().getPointer()};
+}
+
+BridgedASTType BridgedType::getRawLayoutSubstitutedCountType() const {
+  return {unbridged().getRawLayoutSubstitutedCountType().getPointer()};
+}
+
 SwiftInt BridgedType::getCaseIdxOfEnumType(BridgedStringRef name) const {
   return unbridged().getCaseIdxOfEnumType(name.unbridged());
 }
 
+SwiftInt BridgedType::getNumBoxFields(BridgedCanType boxTy) {
+  return boxTy.unbridged()->castTo<swift::SILBoxType>()->getLayout()->getFields().size();
+}
+
+BridgedType BridgedType::getBoxFieldType(BridgedCanType boxTy, SwiftInt idx, BridgedFunction f) {
+  auto *fn = f.getFunction();
+  return swift::getSILBoxFieldType(fn->getTypeExpansionContext(), boxTy.unbridged()->castTo<swift::SILBoxType>(),
+                                   fn->getModule().Types, idx);
+}
+
+bool BridgedType::getBoxFieldIsMutable(BridgedCanType boxTy, SwiftInt idx) {
+  return boxTy.unbridged()->castTo<swift::SILBoxType>()->getLayout()->getFields()[idx].isMutable();
+}
+
 SwiftInt BridgedType::getNumNominalFields() const {
   return unbridged().getNumNominalFields();
 }
@@ -576,8 +593,13 @@ bool BridgedArgument::FunctionArgument_isLexical() const {
   return llvm::cast<swift::SILFunctionArgument>(getArgument())->getLifetime().isLexical();
 }
 
-OptionalBridgedDeclObj BridgedArgument::getVarDecl() const {
-  return {llvm::dyn_cast_or_null<swift::VarDecl>(getArgument()->getDecl())};
+bool BridgedArgument::FunctionArgument_isClosureCapture() const {
+  return llvm::cast<swift::SILFunctionArgument>(
+    getArgument())->isClosureCapture();
+}
+
+OptionalBridgedDeclObj BridgedArgument::getDecl() const {
+  return {getArgument()->getDecl()};
 }
 
 void BridgedArgument::copyFlags(BridgedArgument fromArgument) const {
@@ -604,6 +626,12 @@ const swift::SILDebugLocation &BridgedLocation::getLoc() const {
 BridgedLocation BridgedLocation::getAutogeneratedLocation() const {
   return getLoc().getAutogeneratedLocation();
 }
+BridgedLocation BridgedLocation::getCleanupLocation() const {
+  return getLoc().getCleanupLocation();
+}
+BridgedLocation BridgedLocation::withScopeOf(BridgedLocation other) const {
+  return swift::SILDebugLocation(getLoc().getLocation(), other.getLoc().getScope());
+}
 bool BridgedLocation::hasValidLineNumber() const {
   return getLoc().hasValidLineNumber();
 }
@@ -616,15 +644,24 @@ bool BridgedLocation::isInlined() const {
 bool BridgedLocation::isEqualTo(BridgedLocation rhs) const {
   return getLoc().isEqualTo(rhs.getLoc());
 }
-BridgedSourceLoc BridgedLocation::getSourceLocation() const {
+swift::SourceLoc BridgedLocation::getSourceLocation() const {
   swift::SILDebugLocation debugLoc = getLoc();
   swift::SILLocation silLoc = debugLoc.getLocation();
-  swift::SourceLoc sourceLoc = silLoc.getSourceLoc();
-  return BridgedSourceLoc(sourceLoc.getOpaquePointerValue());
+  return silLoc.getSourceLoc();
+}
+bool BridgedLocation::isFilenameAndLocation() const {
+  return getLoc().getLocation().isFilenameAndLocation();
+}
+BridgedLocation::FilenameAndLocation BridgedLocation::getFilenameAndLocation() const {
+  auto fnal = getLoc().getLocation().getFilenameAndLocation();
+  return {BridgedStringRef(fnal->filename), (SwiftInt)fnal->line, (SwiftInt)fnal->column};
 }
 bool BridgedLocation::hasSameSourceLocation(BridgedLocation rhs) const {
   return getLoc().hasSameSourceLocation(rhs.getLoc());
 }
+OptionalBridgedDeclObj BridgedLocation::getDecl() const {
+  return {getLoc().getLocation().getAsASTNode<swift::Decl>()};
+}
 BridgedLocation BridgedLocation::fromNominalTypeDecl(BridgedDeclObj decl) {
   return swift::SILDebugLocation(decl.unbridged(), nullptr);
 }
@@ -645,16 +682,46 @@ BridgedStringRef BridgedFunction::getName() const {
 }
 
 BridgedLocation BridgedFunction::getLocation() const {
-  return {swift::SILDebugLocation(getFunction()->getLocation(), getFunction()->getDebugScope())}; 
+  return {swift::SILDebugLocation(getFunction()->getLocation(), getFunction()->getDebugScope())};
+}
+
+bool BridgedFunction::isAccessor() const {
+  if (auto *valDecl = getFunction()->getDeclRef().getDecl()) {
+    return llvm::isa<swift::AccessorDecl>(valDecl);
+  }
+  return false;
+}
+
+BridgedStringRef BridgedFunction::getAccessorName() const {
+  auto *accessorDecl  = llvm::cast<swift::AccessorDecl>(getFunction()->getDeclRef().getDecl());
+  return accessorKindName(accessorDecl->getAccessorKind());
+}
+
+bool BridgedFunction::isInitializer() const {
+  return getFunction()->getDeclRef().isConstructor();
+}
+
+bool BridgedFunction::isDeinitializer() const {
+  return getFunction()->getDeclRef().isDestructor();
+}
+
+bool BridgedFunction::isImplicit() const {
+  if (auto *funcDecl = getFunction()->getDeclRef().getAbstractFunctionDecl()) {
+    return funcDecl->isImplicit();
+  }
+  return false;
 }
 
 bool BridgedFunction::hasOwnership() const { return getFunction()->hasOwnership(); }
 
 bool BridgedFunction::hasLoweredAddresses() const { return getFunction()->getModule().useLoweredAddresses(); }
 
+BridgedCanType BridgedFunction::getLoweredFunctionType() const {
+  return getFunction()->getLoweredFunctionType();
+}
+
 BridgedCanType BridgedFunction::getLoweredFunctionTypeInContext() const {
-  auto expansion = getFunction()->getTypeExpansionContext();
-  return getFunction()->getLoweredFunctionTypeInContext(expansion);
+  return getFunction()->getLoweredFunctionTypeInContext();
 }
 
 BridgedGenericSignature BridgedFunction::getGenericSignature() const {
@@ -767,6 +834,11 @@ BridgedFunction::InlineStrategy BridgedFunction::getInlineStrategy() const {
   return (InlineStrategy)getFunction()->getInlineStrategy();
 }
 
+BridgedFunction::ABILanguage BridgedFunction::getSILFunctionLanguage() const {
+  auto rep = getFunction()->getLoweredFunctionType()->getRepresentation();
+  return (ABILanguage)swift::getSILFunctionLanguage(rep);
+}
+
 BridgedFunction::ThunkKind BridgedFunction::isThunk() const {
   return (ThunkKind)getFunction()->isThunk();
 }
@@ -775,14 +847,6 @@ void BridgedFunction::setThunk(ThunkKind kind) const {
   getFunction()->setThunk((swift::IsThunk_t)kind);
 }
 
-bool BridgedFunction::isSerialized() const {
-  return getFunction()->isSerialized();
-}
-
-bool BridgedFunction::isAnySerialized() const {
-  return getFunction()->isAnySerialized();
-}
-
 BridgedFunction::SerializedKind BridgedFunction::getSerializedKind() const {
   return (SerializedKind)getFunction()->getSerializedKind();
 }
@@ -799,6 +863,14 @@ bool BridgedFunction::needsStackProtection() const {
   return getFunction()->needsStackProtection();
 }
 
+bool BridgedFunction::shouldOptimize() const {
+  return getFunction()->shouldOptimize();
+}
+
+bool BridgedFunction::isReferencedInModule() const {
+  return getFunction()->getRefCount() != 0;
+}
+
 bool BridgedFunction::wasDeserializedCanonical() const {
   return getFunction()->wasDeserializedCanonical();
 }
@@ -823,6 +895,14 @@ void BridgedFunction::setIsSerialized(bool isSerialized) const {
   getFunction()->setSerializedKind(isSerialized ? swift::IsSerialized : swift::IsNotSerialized);
 }
 
+bool BridgedFunction::conformanceMatchesActorIsolation(BridgedConformance conformance) const {
+  return swift::matchesActorIsolation(conformance.unbridged(), getFunction());
+}
+
+bool BridgedFunction::isSpecialization() const {
+  return getFunction()->isSpecialization();
+}
+
 bool BridgedFunction::isResilientNominalDecl(BridgedDeclObj decl) const {
   return decl.getAs<swift::NominalTypeDecl>()->isResilient(getFunction()->getModule().getSwiftModule(),
                                                            getFunction()->getResilienceExpansion());
@@ -871,15 +951,27 @@ bool BridgedGlobalVar::isLet() const { return getGlobal()->isLet(); }
 
 void BridgedGlobalVar::setLet(bool value) const { getGlobal()->setLet(value); }
 
+bool BridgedGlobalVar::markedAsUsed() const {
+  return getGlobal()->markedAsUsed();
+}
+
+void BridgedGlobalVar::setMarkedAsUsed(bool value) const {
+  getGlobal()->setMarkedAsUsed(value);
+}
+
+BridgedType BridgedGlobalVar::getType() const {
+  return getGlobal()->getLoweredType();
+}
+
 BridgedLinkage BridgedGlobalVar::getLinkage() const {
   return (BridgedLinkage)getGlobal()->getLinkage();
 }
 
-BridgedSourceLoc BridgedGlobalVar::getSourceLocation() const {
+swift::SourceLoc BridgedGlobalVar::getSourceLocation() const {
   if (getGlobal()->hasLocation())
     return getGlobal()->getLocation().getSourceLoc();
   else
-    return BridgedSourceLoc();
+    return swift::SourceLoc();
 }
 
 bool BridgedGlobalVar::isPossiblyUsedExternally() const {
@@ -994,6 +1086,10 @@ bool BridgedInstruction::shouldBeForwarding() const {
          llvm::isa<swift::OwnershipForwardingMultipleValueInstruction>(unbridged());
 }
 
+bool BridgedInstruction::isIdenticalTo(BridgedInstruction inst) const {
+  return unbridged()->isIdenticalTo(inst.unbridged());
+}
+
 SwiftInt BridgedInstruction::MultipleValueInstruction_getNumResults() const {
   return getAs<swift::MultipleValueInstruction>()->getNumResults();
 }
@@ -1104,6 +1200,13 @@ BridgedCanType BridgedInstruction::InitExistentialRefInst_getFormalConcreteType(
   return getAs<swift::InitExistentialRefInst>()->getFormalConcreteType();
 }
 
+bool BridgedInstruction::OpenExistentialAddr_isImmutable() const {
+  switch (getAs<swift::OpenExistentialAddrInst>()->getAccessKind()) {
+    case swift::OpenedExistentialAccess::Immutable: return true;
+    case swift::OpenedExistentialAccess::Mutable: return false;
+  }
+}
+
 BridgedGlobalVar BridgedInstruction::GlobalAccessInst_getGlobal() const {
   return {getAs<swift::GlobalAccessInst>()->getReferencedGlobal()};
 }
@@ -1116,12 +1219,9 @@ BridgedFunction BridgedInstruction::FunctionRefBaseInst_getReferencedFunction()
   return {getAs<swift::FunctionRefBaseInst>()->getInitiallyReferencedFunction()};
 }
 
-BridgedInstruction::OptionalInt BridgedInstruction::IntegerLiteralInst_getValue() const {
+BridgedOptionalInt BridgedInstruction::IntegerLiteralInst_getValue() const {
   llvm::APInt result = getAs<swift::IntegerLiteralInst>()->getValue();
-  if (result.getSignificantBits() <= std::min(std::numeric_limits<SwiftInt>::digits, 64)) {
-    return {(SwiftInt)result.getSExtValue(), true};
-  }
-  return {0, false};
+  return getFromAPInt(result);
 }
 
 BridgedStringRef BridgedInstruction::StringLiteralInst_getValue() const {
@@ -1208,6 +1308,10 @@ SwiftInt BridgedInstruction::InjectEnumAddrInst_caseIndex() const {
   return getAs<swift::InjectEnumAddrInst>()->getCaseIndex();
 }
 
+BridgedDeclObj BridgedInstruction::InjectEnumAddrInst_element() const {
+  return {getAs<swift::InjectEnumAddrInst>()->getElement()};
+}
+
 SwiftInt BridgedInstruction::RefElementAddrInst_fieldIndex() const {
   return getAs<swift::RefElementAddrInst>()->getFieldIndex();
 }
@@ -1249,13 +1353,21 @@ BridgedGenericSpecializationInformation BridgedInstruction::ApplyInst_getSpecial
 }
 
 bool BridgedInstruction::TryApplyInst_getNonAsync() const {
-  return getAs<swift::TryApplyInst>()->isNonAsync();  
+  return getAs<swift::TryApplyInst>()->isNonAsync();
 }
 
 BridgedGenericSpecializationInformation BridgedInstruction::TryApplyInst_getSpecializationInfo() const {
   return {getAs<swift::TryApplyInst>()->getSpecializationInfo()};
 }
 
+bool BridgedInstruction::BeginApplyInst_getNonThrowing() const {
+  return getAs<swift::BeginApplyInst>()->isNonThrowing();
+}
+
+bool BridgedInstruction::BeginApplyInst_getNonAsync() const {
+  return getAs<swift::BeginApplyInst>()->isNonAsync();
+}
+
 BridgedDeclRef BridgedInstruction::ClassMethodInst_getMember() const {
   return getAs<swift::ClassMethodInst>()->getMember();
 }
@@ -1265,7 +1377,7 @@ BridgedDeclRef BridgedInstruction::WitnessMethodInst_getMember() const {
 }
 
 BridgedCanType BridgedInstruction::WitnessMethodInst_getLookupType() const {
-  return getAs<swift::WitnessMethodInst>()->getLookupType();  
+  return getAs<swift::WitnessMethodInst>()->getLookupType();
 }
 
 BridgedDeclObj BridgedInstruction::WitnessMethodInst_getLookupProtocol() const {
@@ -1305,6 +1417,14 @@ bool BridgedInstruction::AllocStackInst_usesMoveableValueDebugInfo() const {
   return getAs<swift::AllocStackInst>()->usesMoveableValueDebugInfo();
 }
 
+bool BridgedInstruction::AllocStackInst_isLexical() const {
+  return getAs<swift::AllocStackInst>()->isLexical();
+}
+
+bool BridgedInstruction::AllocBoxInst_hasDynamicLifetime() const {
+  return getAs<swift::AllocBoxInst>()->hasDynamicLifetime();
+}
+
 bool BridgedInstruction::AllocRefInstBase_isObjc() const {
   return getAs<swift::AllocRefInstBase>()->isObjC();
 }
@@ -1329,10 +1449,18 @@ SwiftInt BridgedInstruction::BeginApplyInst_numArguments() const {
   return getAs<swift::BeginApplyInst>()->getNumArguments();
 }
 
+bool BridgedInstruction::BeginApplyInst_isCalleeAllocated() const {
+  return getAs<swift::BeginApplyInst>()->isCalleeAllocated();
+}
+
 SwiftInt BridgedInstruction::TryApplyInst_numArguments() const {
   return getAs<swift::TryApplyInst>()->getNumArguments();
 }
 
+BridgedArgumentConvention BridgedInstruction::YieldInst_getConvention(BridgedOperand forOperand) const {
+  return castToArgumentConvention(getAs<swift::YieldInst>()->getArgumentConventionForOperand(*forOperand.op));
+}
+
 BridgedBasicBlock BridgedInstruction::BranchInst_getTargetBlock() const {
   return {getAs<swift::BranchInst>()->getDestBB()};
 }
@@ -1358,26 +1486,26 @@ BridgedInstruction::MarkDependenceKind BridgedInstruction::MarkDependenceInst_de
   return (MarkDependenceKind)getAs<swift::MarkDependenceInst>()->dependenceKind();
 }
 
-void BridgedInstruction::MarkDependenceInst_resolveToNonEscaping() const {
-  getAs<swift::MarkDependenceInst>()->resolveToNonEscaping();
+void BridgedInstruction::MarkDependenceInstruction_resolveToNonEscaping() const {
+  if (auto *mdi = llvm::dyn_cast<swift::MarkDependenceInst>(unbridged())) {
+    mdi->resolveToNonEscaping();
+  } else {
+    getAs<swift::MarkDependenceAddrInst>()->resolveToNonEscaping();
+  }
 }
 
-void BridgedInstruction::MarkDependenceInst_settleToEscaping() const {
-  getAs<swift::MarkDependenceInst>()->settleToEscaping();
+void BridgedInstruction::MarkDependenceInstruction_settleToEscaping() const {
+  if (auto *mdi = llvm::dyn_cast<swift::MarkDependenceInst>(unbridged())) {
+    mdi->settleToEscaping();
+  } else {
+    getAs<swift::MarkDependenceAddrInst>()->settleToEscaping();
+  }
 }
 
 BridgedInstruction::MarkDependenceKind BridgedInstruction::MarkDependenceAddrInst_dependenceKind() const {
   return (MarkDependenceKind)getAs<swift::MarkDependenceAddrInst>()->dependenceKind();
 }
 
-void BridgedInstruction::MarkDependenceAddrInst_resolveToNonEscaping() const {
-  getAs<swift::MarkDependenceAddrInst>()->resolveToNonEscaping();
-}
-
-void BridgedInstruction::MarkDependenceAddrInst_settleToEscaping() const {
-  getAs<swift::MarkDependenceAddrInst>()->settleToEscaping();
-}
-
 SwiftInt BridgedInstruction::BeginAccessInst_getAccessKind() const {
   return (SwiftInt)getAs<swift::BeginAccessInst>()->getAccessKind();
 }
@@ -1390,6 +1518,18 @@ bool BridgedInstruction::BeginAccessInst_isUnsafe() const {
   return getAs<swift::BeginAccessInst>()->getEnforcement() == swift::SILAccessEnforcement::Unsafe;
 }
 
+void BridgedInstruction::BeginAccess_setAccessKind(SwiftInt accessKind) const {
+  getAs<swift::BeginAccessInst>()->setAccessKind((swift::SILAccessKind)accessKind);
+}
+
+SwiftInt BridgedInstruction::BeginAccessInst_getEnforcement() const {
+  return (SwiftInt)getAs<swift::BeginAccessInst>()->getEnforcement();
+}
+
+void BridgedInstruction::BeginAccess_setEnforcement(SwiftInt accessKind) const {
+  getAs<swift::BeginAccessInst>()->setEnforcement((swift::SILAccessEnforcement)accessKind);
+}
+
 bool BridgedInstruction::CopyAddrInst_isTakeOfSrc() const {
   return getAs<swift::CopyAddrInst>()->isTakeOfSrc();
 }
@@ -1398,6 +1538,19 @@ bool BridgedInstruction::CopyAddrInst_isInitializationOfDest() const {
   return getAs<swift::CopyAddrInst>()->isInitializationOfDest();
 }
 
+void BridgedInstruction::CopyAddrInst_setIsTakeOfSrc(bool isTakeOfSrc) const {
+  return getAs<swift::CopyAddrInst>()->setIsTakeOfSrc(isTakeOfSrc ? swift::IsTake : swift::IsNotTake);
+}
+
+void BridgedInstruction::CopyAddrInst_setIsInitializationOfDest(bool isInitializationOfDest) const {
+  return getAs<swift::CopyAddrInst>()->setIsInitializationOfDest(
+      isInitializationOfDest ? swift::IsInitialization : swift::IsNotInitialization);
+}
+
+bool BridgedInstruction::DeallocBoxInst_isDeadEnd() const {
+  return getAs<swift::DeallocBoxInst>()->isDeadEnd();
+}
+
 bool BridgedInstruction::ExplicitCopyAddrInst_isTakeOfSrc() const {
   return getAs<swift::ExplicitCopyAddrInst>()->isTakeOfSrc();
 }
@@ -1410,6 +1563,14 @@ SwiftInt BridgedInstruction::MarkUninitializedInst_getKind() const {
   return (SwiftInt)getAs<swift::MarkUninitializedInst>()->getMarkUninitializedKind();
 }
 
+SwiftInt BridgedInstruction::MarkUnresolvedNonCopyableValue_getCheckKind() const {
+  return (SwiftInt)getAs<swift::MarkUnresolvedNonCopyableValueInst>()->getCheckKind();
+}
+
+bool BridgedInstruction::MarkUnresolvedNonCopyableValue_isStrict() const {
+  return getAs<swift::MarkUnresolvedNonCopyableValueInst>()->isStrict();
+}
+
 void BridgedInstruction::RefCountingInst_setIsAtomic(bool isAtomic) const {
   getAs<swift::RefCountingInst>()->setAtomicity(
       isAtomic ? swift::RefCountingInst::Atomicity::Atomic
@@ -1441,6 +1602,14 @@ void BridgedInstruction::TermInst_replaceBranchTarget(BridgedBasicBlock from, Br
                                                 to.unbridged());
 }
 
+BridgedSubstitutionMap BridgedInstruction::KeyPathInst_getSubstitutionMap() const {
+  return getAs<swift::KeyPathInst>()->getSubstitutions();
+}
+
+bool BridgedInstruction::KeyPathInst_hasPattern() const {
+  return getAs<swift::KeyPathInst>()->hasPattern();
+}
+
 SwiftInt BridgedInstruction::KeyPathInst_getNumComponents() const {
   if (swift::KeyPathPattern *pattern = getAs<swift::KeyPathInst>()->getPattern()) {
     return (SwiftInt)pattern->getComponents().size();
@@ -1481,31 +1650,33 @@ void BridgedInstruction::CheckedCastBranch_updateSourceFormalTypeFromOperandLowe
 }
 
 BridgedCanType BridgedInstruction::UnconditionalCheckedCast_getSourceFormalType() const {
-  return {getAs<swift::UnconditionalCheckedCastInst>()->getSourceFormalType()};  
+  return {getAs<swift::UnconditionalCheckedCastInst>()->getSourceFormalType()};
 }
 
 BridgedCanType BridgedInstruction::UnconditionalCheckedCast_getTargetFormalType() const {
-  return {getAs<swift::UnconditionalCheckedCastInst>()->getTargetFormalType()};    
+  return {getAs<swift::UnconditionalCheckedCastInst>()->getTargetFormalType()};
 }
 
-BridgedInstruction::CastingIsolatedConformances
-BridgedInstruction::UnconditionalCheckedCast_getIsolatedConformances() const {
-  return static_cast<BridgedInstruction::CastingIsolatedConformances>(
-      getAs<swift::UnconditionalCheckedCastInst>()->getIsolatedConformances());
+BridgedInstruction::CheckedCastInstOptions
+BridgedInstruction::UnconditionalCheckedCast_getCheckedCastOptions() const {
+  return BridgedInstruction::CheckedCastInstOptions{
+      getAs<swift::UnconditionalCheckedCastInst>()->getCheckedCastOptions()
+        .getStorage()};
 }
 
 BridgedCanType BridgedInstruction::UnconditionalCheckedCastAddr_getSourceFormalType() const {
-  return {getAs<swift::UnconditionalCheckedCastAddrInst>()->getSourceFormalType()};  
+  return {getAs<swift::UnconditionalCheckedCastAddrInst>()->getSourceFormalType()};
 }
 
 BridgedCanType BridgedInstruction::UnconditionalCheckedCastAddr_getTargetFormalType() const {
-  return {getAs<swift::UnconditionalCheckedCastAddrInst>()->getTargetFormalType()};    
+  return {getAs<swift::UnconditionalCheckedCastAddrInst>()->getTargetFormalType()};
 }
 
-BridgedInstruction::CastingIsolatedConformances
-BridgedInstruction::UnconditionalCheckedCastAddr_getIsolatedConformances() const {
-  return static_cast<BridgedInstruction::CastingIsolatedConformances>(
-      getAs<swift::UnconditionalCheckedCastAddrInst>()->getIsolatedConformances());
+BridgedInstruction::CheckedCastInstOptions
+BridgedInstruction::UnconditionalCheckedCastAddr_getCheckedCastOptions() const {
+  return BridgedInstruction::CheckedCastInstOptions{
+      getAs<swift::UnconditionalCheckedCastAddrInst>()->getCheckedCastOptions()
+        .getStorage()};
 }
 
 BridgedBasicBlock BridgedInstruction::CheckedCastBranch_getSuccessBlock() const {
@@ -1516,10 +1687,11 @@ BridgedBasicBlock BridgedInstruction::CheckedCastBranch_getFailureBlock() const
   return {getAs<swift::CheckedCastBranchInst>()->getFailureBB()};
 }
 
-BridgedInstruction::CastingIsolatedConformances
-BridgedInstruction::CheckedCastBranch_getIsolatedConformances() const {
-  return static_cast<BridgedInstruction::CastingIsolatedConformances>(
-      getAs<swift::CheckedCastBranchInst>()->getIsolatedConformances());
+BridgedInstruction::CheckedCastInstOptions
+BridgedInstruction::CheckedCastBranch_getCheckedCastOptions() const {
+  return BridgedInstruction::CheckedCastInstOptions{
+      getAs<swift::CheckedCastBranchInst>()->getCheckedCastOptions()
+        .getStorage()};
 }
 
 BridgedCanType BridgedInstruction::CheckedCastAddrBranch_getSourceFormalType() const {
@@ -1527,7 +1699,7 @@ BridgedCanType BridgedInstruction::CheckedCastAddrBranch_getSourceFormalType() c
 }
 
 BridgedCanType BridgedInstruction::CheckedCastAddrBranch_getTargetFormalType() const {
-  return {getAs<swift::CheckedCastAddrBranchInst>()->getTargetFormalType()};  
+  return {getAs<swift::CheckedCastAddrBranchInst>()->getTargetFormalType()};
 }
 
 BridgedBasicBlock BridgedInstruction::CheckedCastAddrBranch_getSuccessBlock() const {
@@ -1550,10 +1722,11 @@ BridgedInstruction::CastConsumptionKind BridgedInstruction::CheckedCastAddrBranc
            getAs<swift::CheckedCastAddrBranchInst>()->getConsumptionKind());
 }
 
-BridgedInstruction::CastingIsolatedConformances
-BridgedInstruction::CheckedCastAddrBranch_getIsolatedConformances() const {
-  return static_cast<BridgedInstruction::CastingIsolatedConformances>(
-      getAs<swift::CheckedCastAddrBranchInst>()->getIsolatedConformances());
+BridgedInstruction::CheckedCastInstOptions
+BridgedInstruction::CheckedCastAddrBranch_getCheckedCastOptions() const {
+  return BridgedInstruction::CheckedCastInstOptions{
+      getAs<swift::CheckedCastAddrBranchInst>()->getCheckedCastOptions()
+        .getStorage()};
 }
 
 BridgedSubstitutionMap BridgedInstruction::ApplySite_getSubstitutionMap() const {
@@ -1587,19 +1760,6 @@ BridgedCanType BridgedInstruction::TypeValueInst_getParamType() const {
   return getAs<swift::TypeValueInst>()->getParamType();
 }
 
-SwiftInt BridgedInstruction::TypeValueInst_getValue() const {
-  auto tvi = getAs<swift::TypeValueInst>();
-
-  // Assume we've already checked that the parameter type is an IntegerType.
-  auto integer = tvi->getParamType()->castTo<swift::IntegerType>();
-
-  if (integer->isNegative()) {
-    return integer->getValue().getSExtValue();
-  } else {
-    return integer->getValue().getZExtValue();
-  }
-}
-
 //===----------------------------------------------------------------------===//
 //                     VarDeclInst and DebugVariableInst
 //===----------------------------------------------------------------------===//
@@ -1736,6 +1896,14 @@ BridgedArgument BridgedBasicBlock::addFunctionArgument(BridgedType type) const {
   return {unbridged()->createFunctionArgument(type.unbridged())};
 }
 
+BridgedArgument BridgedBasicBlock::insertFunctionArgument(SwiftInt atPosition, BridgedType type,
+                                                          BridgedValue::Ownership ownership,
+                                                          OptionalBridgedDeclObj decl) const {
+  return {unbridged()->insertFunctionArgument((unsigned)atPosition, type.unbridged(),
+                                              BridgedValue::unbridge(ownership),
+                                              decl.getAs<swift::ValueDecl>())};
+}
+
 void BridgedBasicBlock::eraseArgument(SwiftInt index) const {
   unbridged()->eraseArgument(index);
 }
@@ -1909,10 +2077,6 @@ BridgedCanType BridgedWitnessTableEntry::getAssociatedConformanceRequirement() c
   return unbridged().getAssociatedConformanceWitness().Requirement;
 }
 
-BridgedCanType BridgedWitnessTableEntry::getAssociatedConformanceSubstType() const {
-  return {unbridged().getAssociatedConformanceWitness().SubstType};
-}
-
 BridgedConformance BridgedWitnessTableEntry::getAssociatedConformanceWitness() const {
   return {unbridged().getAssociatedConformanceWitness().Witness};
 }
@@ -1944,11 +2108,9 @@ BridgedWitnessTableEntry BridgedWitnessTableEntry::createAssociatedType(BridgedD
 }
 
 BridgedWitnessTableEntry BridgedWitnessTableEntry::createAssociatedConformance(BridgedCanType requirement,
-                                                                               BridgedCanType substType,
                                                                                BridgedConformance witness) {
   return bridge(swift::SILWitnessTable::Entry(
     swift::SILWitnessTable::AssociatedConformanceWitness{requirement.unbridged(),
-                                                         substType.unbridged(),
                                                          witness.unbridged()}));
 }
 
@@ -1971,6 +2133,10 @@ bool BridgedWitnessTable::isDeclaration() const {
   return table->isDeclaration();
 }
 
+bool BridgedWitnessTable::isSpecialized() const {
+  return table->isSpecialized();
+}
+
 SwiftInt BridgedDefaultWitnessTable::getNumEntries() const {
   return SwiftInt(table->getEntries().size());
 }
@@ -2026,7 +2192,25 @@ swift::SILBuilder BridgedBuilder::unbridged() const {
 }
 
 swift::SILLocation BridgedBuilder::regularLoc() const {
-  return swift::RegularLocation(loc.getLoc().getLocation());
+  auto l = loc.getLoc().getLocation();
+  switch (l.getKind()) {
+    case swift::SILLocation::ReturnKind:
+    case swift::SILLocation::ImplicitReturnKind:
+    case swift::SILLocation::ArtificialUnreachableKind:
+      return swift::RegularLocation(l);
+    default:
+      return l;
+  }
+}
+
+swift::SILLocation BridgedBuilder::returnLoc() const {
+  auto l = loc.getLoc().getLocation();
+  switch (l.getKind()) {
+    case swift::SILLocation::ArtificialUnreachableKind:
+      return swift::RegularLocation(l);
+    default:
+      return l;
+  }
 }
 
 BridgedInstruction BridgedBuilder::createBuiltin(BridgedStringRef name, BridgedType type,
@@ -2054,9 +2238,11 @@ BridgedInstruction BridgedBuilder::createCondFail(BridgedValue condition, Bridge
                                      message.unbridged())};
 }
 
-BridgedInstruction BridgedBuilder::createIntegerLiteral(BridgedType type, SwiftInt value) const {
-  return {
-      unbridged().createIntegerLiteral(regularLoc(), type.unbridged(), value)};
+BridgedInstruction
+BridgedBuilder::createIntegerLiteral(BridgedType type, SwiftInt value,
+                                     bool treatAsSigned) const {
+  return {unbridged().createIntegerLiteral(regularLoc(), type.unbridged(),
+                                           value, treatAsSigned)};
 }
 
 BridgedInstruction BridgedBuilder::createAllocRef(BridgedType type,
@@ -2070,6 +2256,19 @@ BridgedInstruction BridgedBuilder::createAllocRef(BridgedType type,
       )};
 }
 
+BridgedInstruction BridgedBuilder::createAllocStack(BridgedType type,
+                                                    BridgedSILDebugVariable debugVar,
+                                                    bool hasDynamicLifetime,
+                                                    bool isLexical,
+                                                    bool isFromVarDecl,
+                                                    bool wasMoved) const {
+  return {unbridged().createAllocStack(
+      regularLoc(), type.unbridged(), debugVar.unbridge(),
+      swift::HasDynamicLifetime_t(hasDynamicLifetime),
+      swift::IsLexical_t(isLexical), swift::IsFromVarDecl_t(isFromVarDecl),
+      swift::UsesMoveableValueDebugInfo_t(wasMoved), /*skipVarDeclAssert=*/ true)};
+}
+
 BridgedInstruction BridgedBuilder::createAllocStack(BridgedType type,
                                                     bool hasDynamicLifetime,
                                                     bool isLexical,
@@ -2121,6 +2320,11 @@ BridgedInstruction BridgedBuilder::createUncheckedAddrCast(BridgedValue op, Brid
                                               type.unbridged())};
 }
 
+BridgedInstruction BridgedBuilder::createUncheckedValueCast(BridgedValue op, BridgedType type) const {
+  return {unbridged().createUncheckedValueCast(regularLoc(), op.getSILValue(),
+                                              type.unbridged())};
+}
+
 BridgedInstruction BridgedBuilder::createUpcast(BridgedValue op, BridgedType type) const {
   return {unbridged().createUpcast(regularLoc(), op.getSILValue(),
                                    type.unbridged())};
@@ -2129,13 +2333,13 @@ BridgedInstruction BridgedBuilder::createUpcast(BridgedValue op, BridgedType typ
 BridgedInstruction BridgedBuilder::createCheckedCastAddrBranch(
     BridgedValue source, BridgedCanType sourceFormalType,
     BridgedValue destination, BridgedCanType targetFormalType,
-    BridgedInstruction::CastingIsolatedConformances isolatedConformances,
+    BridgedInstruction::CheckedCastInstOptions options,
     BridgedInstruction::CastConsumptionKind consumptionKind,
     BridgedBasicBlock successBlock, BridgedBasicBlock failureBlock) const
 {
   return {unbridged().createCheckedCastAddrBranch(
             regularLoc(),
-            (swift::CastingIsolatedConformances)isolatedConformances,
+            swift::CheckedCastInstOptions(options.storage),
             (swift::CastConsumptionKind)consumptionKind,
             source.getSILValue(), sourceFormalType.unbridged(),
             destination.getSILValue(), targetFormalType.unbridged(),
@@ -2143,13 +2347,13 @@ BridgedInstruction BridgedBuilder::createCheckedCastAddrBranch(
 }
 
 BridgedInstruction BridgedBuilder::createUnconditionalCheckedCastAddr(
-    BridgedInstruction::CastingIsolatedConformances isolatedConformances,
+    BridgedInstruction::CheckedCastInstOptions options,
     BridgedValue source, BridgedCanType sourceFormalType,
     BridgedValue destination, BridgedCanType targetFormalType) const
 {
   return {unbridged().createUnconditionalCheckedCastAddr(
             regularLoc(),
-            (swift::CastingIsolatedConformances)isolatedConformances,
+            swift::CheckedCastInstOptions(options.storage),
             source.getSILValue(), sourceFormalType.unbridged(),
             destination.getSILValue(), targetFormalType.unbridged())};
 }
@@ -2159,6 +2363,13 @@ BridgedInstruction BridgedBuilder::createLoad(BridgedValue op, SwiftInt ownershi
                                  (swift::LoadOwnershipQualifier)ownership)};
 }
 
+
+BridgedInstruction BridgedBuilder::createUncheckedOwnershipConversion(BridgedValue op,
+                                                                      BridgedValue::Ownership ownership) const {
+  return {unbridged().createUncheckedOwnershipConversion(regularLoc(), op.getSILValue(),
+                                                         BridgedValue::unbridge(ownership))};
+}
+
 BridgedInstruction BridgedBuilder::createLoadBorrow(BridgedValue op) const {
   return {unbridged().createLoadBorrow(regularLoc(), op.getSILValue())};
 }
@@ -2288,6 +2499,19 @@ BridgedInstruction BridgedBuilder::createTryApply(BridgedValue function, Bridged
       arguments.getValues(argValues), normalBB.unbridged(), errorBB.unbridged(), applyOpts, specInfo.data)};
 }
 
+BridgedInstruction BridgedBuilder::createBeginApply(BridgedValue function, BridgedSubstitutionMap subMap,
+                               BridgedValueArray arguments, bool isNonThrowing, bool isNonAsync,
+                               BridgedGenericSpecializationInformation specInfo) const {
+  llvm::SmallVector<swift::SILValue, 16> argValues;
+  swift::ApplyOptions applyOpts;
+  if (isNonThrowing) { applyOpts |= swift::ApplyFlags::DoesNotThrow; }
+  if (isNonAsync) { applyOpts |= swift::ApplyFlags::DoesNotAwait; }
+
+  return {unbridged().createBeginApply(
+      regularLoc(), function.getSILValue(), subMap.unbridged(),
+      arguments.getValues(argValues), applyOpts, specInfo.data)};
+}
+
 BridgedInstruction BridgedBuilder::createWitnessMethod(BridgedCanType lookupType,
                                         BridgedConformance conformance,
                                         BridgedDeclRef member, BridgedType methodType) const {
@@ -2297,7 +2521,7 @@ BridgedInstruction BridgedBuilder::createWitnessMethod(BridgedCanType lookupType
 
 
 BridgedInstruction BridgedBuilder::createReturn(BridgedValue op) const {
-  return {unbridged().createReturn(regularLoc(), op.getSILValue())};
+  return {unbridged().createReturn(returnLoc(), op.getSILValue())};
 }
 
 BridgedInstruction BridgedBuilder::createThrow(BridgedValue op) const {
@@ -2339,7 +2563,7 @@ BridgedInstruction BridgedBuilder::createThinToThickFunction(BridgedValue fn, Br
                                                 resultType.unbridged())};
 }
 
-BridgedInstruction BridgedBuilder::createPartialApply(BridgedValue funcRef, 
+BridgedInstruction BridgedBuilder::createPartialApply(BridgedValue funcRef,
                                                       BridgedValueArray bridgedCapturedArgs,
                                                       BridgedArgumentConvention calleeConvention,
                                                       BridgedSubstitutionMap bridgedSubstitutionMap,
@@ -2354,7 +2578,7 @@ BridgedInstruction BridgedBuilder::createPartialApply(BridgedValue funcRef,
                           : swift::SILFunctionTypeIsolation::forErased(),
       isOnStack ? swift::PartialApplyInst::OnStack
                 : swift::PartialApplyInst::NotOnStack)};
-}                                                                                  
+}
 
 BridgedInstruction BridgedBuilder::createBranch(BridgedBasicBlock destBlock, BridgedValueArray arguments) const {
   llvm::SmallVector<swift::SILValue, 16> argValues;
@@ -2362,8 +2586,15 @@ BridgedInstruction BridgedBuilder::createBranch(BridgedBasicBlock destBlock, Bri
                                    arguments.getValues(argValues))};
 }
 
+BridgedInstruction BridgedBuilder::createCondBranch(BridgedValue condition,
+                                                    BridgedBasicBlock trueBlock,
+                                                    BridgedBasicBlock falseBlock) const {
+  return {unbridged().createCondBranch(regularLoc(), condition.getSILValue(), trueBlock.unbridged(),
+                                       falseBlock.unbridged())};
+}
+
 BridgedInstruction BridgedBuilder::createUnreachable() const {
-  return {unbridged().createUnreachable(regularLoc())};
+  return {unbridged().createUnreachable(loc.getLoc().getLocation())};
 }
 
 BridgedInstruction BridgedBuilder::createObject(BridgedType type,
@@ -2380,6 +2611,10 @@ BridgedInstruction BridgedBuilder::createVector(BridgedValueArray arguments) con
   return {unbridged().createVector(swift::ArtificialUnreachableLocation(), arguments.getValues(argValues))};
 }
 
+BridgedInstruction BridgedBuilder::createVectorBaseAddr(BridgedValue vector) const {
+  return {unbridged().createVectorBaseAddr(regularLoc(), vector.getSILValue())};
+}
+
 BridgedInstruction BridgedBuilder::createGlobalAddr(BridgedGlobalVar global,
                                                     OptionalBridgedValue dependencyToken) const {
   return {unbridged().createGlobalAddr(regularLoc(), global.getGlobal(), dependencyToken.getSILValue())};
@@ -2432,6 +2667,10 @@ BridgedInstruction BridgedBuilder::createDestructureTuple(BridgedValue str) cons
   return {unbridged().createDestructureTuple(regularLoc(), str.getSILValue())};
 }
 
+BridgedInstruction BridgedBuilder::createProjectBox(BridgedValue box, SwiftInt fieldIdx) const {
+  return {unbridged().createProjectBox(regularLoc(), box.getSILValue(), (unsigned)fieldIdx)};
+}
+
 BridgedInstruction BridgedBuilder::createStore(BridgedValue src, BridgedValue dst,
                                SwiftInt ownership) const {
   return {unbridged().createStore(regularLoc(), src.getSILValue(),
@@ -2470,6 +2709,12 @@ BridgedInstruction BridgedBuilder::createEndCOWMutation(BridgedValue instance, b
                                            keepUnique)};
 }
 
+BridgedInstruction
+BridgedBuilder::createEndCOWMutationAddr(BridgedValue instance) const {
+  return {unbridged().createEndCOWMutationAddr(regularLoc(),
+                                               instance.getSILValue())};
+}
+
 BridgedInstruction BridgedBuilder::createMarkDependence(BridgedValue value, BridgedValue base, BridgedInstruction::MarkDependenceKind kind) const {
   return {unbridged().createMarkDependence(regularLoc(), value.getSILValue(), base.getSILValue(), swift::MarkDependenceKind(kind))};
 }
@@ -2480,6 +2725,19 @@ BridgedInstruction BridgedBuilder::createMarkDependenceAddr(BridgedValue value,
       swift::MarkDependenceKind(kind))};
 }
 
+BridgedInstruction BridgedBuilder::createMarkUninitialized(BridgedValue value, SwiftInt kind) const {
+  return {unbridged().createMarkUninitialized(
+      regularLoc(), value.getSILValue(), (swift::MarkUninitializedInst::Kind)kind)};
+}
+
+BridgedInstruction BridgedBuilder::createMarkUnresolvedNonCopyableValue(BridgedValue value,
+                                                                        SwiftInt checkKind, bool isStrict) const {
+  return {unbridged().createMarkUnresolvedNonCopyableValueInst(
+      regularLoc(), value.getSILValue(), (swift::MarkUnresolvedNonCopyableValueInst::CheckKind)checkKind,
+      (swift::MarkUnresolvedNonCopyableValueInst::IsStrict_t)isStrict)};
+}
+
+
 BridgedInstruction BridgedBuilder::createEndAccess(BridgedValue value) const {
   return {unbridged().createEndAccess(regularLoc(), value.getSILValue(), false)};
 }
@@ -2502,6 +2760,346 @@ BridgedInstruction BridgedBuilder::createConvertEscapeToNoEscape(BridgedValue or
   return {unbridged().createConvertEscapeToNoEscape(regularLoc(), originalFunction.getSILValue(), resultType.unbridged(), isLifetimeGuaranteed)};
 }
 
+//===----------------------------------------------------------------------===//
+//                            BridgedBasicBlockSet
+//===----------------------------------------------------------------------===//
+
+bool BridgedBasicBlockSet::contains(BridgedBasicBlock block) const {
+  return set->contains(block.unbridged());
+}
+
+bool BridgedBasicBlockSet::insert(BridgedBasicBlock block) const {
+  return set->insert(block.unbridged());
+}
+
+void BridgedBasicBlockSet::erase(BridgedBasicBlock block) const {
+  set->erase(block.unbridged());
+}
+
+BridgedFunction BridgedBasicBlockSet::getFunction() const {
+  return {set->getFunction()};
+}
+
+//===----------------------------------------------------------------------===//
+//                            BridgedNodeSet
+//===----------------------------------------------------------------------===//
+
+bool BridgedNodeSet::containsValue(BridgedValue value) const {
+  return set->contains(value.getSILValue());
+}
+
+bool BridgedNodeSet::insertValue(BridgedValue value) const {
+  return set->insert(value.getSILValue());
+}
+
+void BridgedNodeSet::eraseValue(BridgedValue value) const {
+  set->erase(value.getSILValue());
+}
+
+bool BridgedNodeSet::containsInstruction(BridgedInstruction inst) const {
+  return set->contains(inst.unbridged()->asSILNode());
+}
+
+bool BridgedNodeSet::insertInstruction(BridgedInstruction inst) const {
+  return set->insert(inst.unbridged()->asSILNode());
+}
+
+void BridgedNodeSet::eraseInstruction(BridgedInstruction inst) const {
+  set->erase(inst.unbridged()->asSILNode());
+}
+
+BridgedFunction BridgedNodeSet::getFunction() const {
+  return {set->getFunction()};
+}
+
+//===----------------------------------------------------------------------===//
+//                            BridgedOperandSet
+//===----------------------------------------------------------------------===//
+
+bool BridgedOperandSet::contains(BridgedOperand operand) const {
+  return set->contains(operand.op);
+}
+
+bool BridgedOperandSet::insert(BridgedOperand operand) const {
+  return set->insert(operand.op);
+}
+
+void BridgedOperandSet::erase(BridgedOperand operand) const {
+  set->erase(operand.op);
+}
+
+BridgedFunction BridgedOperandSet::getFunction() const {
+  return {set->getFunction()};
+}
+
+//===----------------------------------------------------------------------===//
+//                             BridgedContext
+//===----------------------------------------------------------------------===//
+
+static_assert((int)BridgedContext::NotificationKind::Instructions ==
+              (int)swift::SILContext::NotificationKind::Instructions);
+static_assert((int)BridgedContext::NotificationKind::Calls ==
+              (int)swift::SILContext::NotificationKind::Calls);
+static_assert((int)BridgedContext::NotificationKind::Branches ==
+              (int)swift::SILContext::NotificationKind::Branches);
+static_assert((int)BridgedContext::NotificationKind::Effects ==
+              (int)swift::SILContext::NotificationKind::Effects);
+static_assert((int)BridgedContext::NotificationKind::FunctionTables ==
+              (int)swift::SILContext::NotificationKind::FunctionTables);
+
+static_assert((int)BridgedContext::SILStage::Raw == (int)swift::SILStage::Raw);
+static_assert((int)BridgedContext::SILStage::Canonical == (int)swift::SILStage::Canonical);
+static_assert((int)BridgedContext::SILStage::Lowered == (int)swift::SILStage::Lowered);
+
+bool BridgedContext::isTransforming(BridgedFunction function) const {
+  return context->getFunction() == function.getFunction();
+}
+
+void BridgedContext::notifyChanges(NotificationKind changeKind) const {
+  context->notifyChanges((swift::SILContext::NotificationKind)changeKind);
+}
+
+BridgedContext::SILStage BridgedContext::getSILStage() const {
+  return (SILStage)context->getModule()->getStage();
+}
+
+bool BridgedContext::moduleIsSerialized() const {
+  return context->getModule()->isSerialized();
+}
+
+bool BridgedContext::moduleHasLoweredAddresses() const {
+  return context->getModule()->useLoweredAddresses();
+}
+
+BridgedDeclObj BridgedContext::getCurrentModuleContext() const {
+  return {context->getModule()->getSwiftModule()};
+}
+
+OptionalBridgedFunction BridgedContext::lookupFunction(BridgedStringRef name) const {
+  return {context->getModule()->lookUpFunction(name.unbridged())};
+}
+
+OptionalBridgedVTable BridgedContext::lookupVTable(BridgedDeclObj classDecl) const {
+  return {context->getModule()->lookUpVTable(classDecl.getAs<swift::ClassDecl>())};
+}
+
+OptionalBridgedVTable BridgedContext::lookupSpecializedVTable(BridgedType classType) const {
+  return {context->getModule()->lookUpSpecializedVTable(classType.unbridged())};
+}
+
+OptionalBridgedFunction BridgedContext::loadFunction(BridgedStringRef name, bool loadCalleesRecursively) const {
+  return {context->getModule()->loadFunction(name.unbridged(),
+                            loadCalleesRecursively
+                                ? swift::SILModule::LinkingMode::LinkAll
+                                : swift::SILModule::LinkingMode::LinkNormal)};
+}
+
+void BridgedContext::loadFunction(BridgedFunction function, bool loadCalleesRecursively) const {
+  context->getModule()->loadFunction(function.getFunction(),
+                    loadCalleesRecursively ? swift::SILModule::LinkingMode::LinkAll
+                                           : swift::SILModule::LinkingMode::LinkNormal);
+}
+
+BridgedSubstitutionMap BridgedContext::getContextSubstitutionMap(BridgedType type) const {
+  swift::SILType ty = type.unbridged();
+  return ty.getASTType()->getContextSubstitutionMap();
+}
+
+BridgedType BridgedContext::getBuiltinIntegerType(SwiftInt bitWidth) const {
+  return swift::SILType::getBuiltinIntegerType(bitWidth, context->getModule()->getASTContext());
+}
+
+BridgedASTType BridgedContext::getTupleType(BridgedArrayRef elementTypes) const {
+  llvm::SmallVector<swift::TupleTypeElt, 8> elements;
+  for (auto bridgedElmtTy :  elementTypes.unbridged<BridgedASTType>()) {
+    elements.push_back(bridgedElmtTy.unbridged());
+  }
+  return {swift::TupleType::get(elements, context->getModule()->getASTContext())};
+}
+
+BridgedDeclObj BridgedContext::getSwiftArrayDecl() const {
+  return {context->getModule()->getASTContext().getArrayDecl()};
+}
+
+BridgedDeclObj BridgedContext::getSwiftMutableSpanDecl() const {
+  return {context->getModule()->getASTContext().getMutableSpanDecl()};
+}
+
+BridgedValue BridgedContext::getSILUndef(BridgedType type) const {
+  return {swift::SILUndef::get(context->getFunction(), type.unbridged())};
+}
+
+BridgedConformance BridgedContext::getSpecializedConformance(
+                                                     BridgedConformance genericConformance,
+                                                     BridgedASTType type,
+                                                     BridgedSubstitutionMap substitutions) const {
+  auto &ctxt = context->getModule()->getASTContext();
+  auto *genConf = llvm::cast<swift::NormalProtocolConformance>(genericConformance.unbridged().getConcrete());
+  auto *c = ctxt.getSpecializedConformance(type.unbridged(), genConf, substitutions.unbridged());
+  return swift::ProtocolConformanceRef(c);
+}
+
+OptionalBridgedWitnessTable BridgedContext::lookupWitnessTable(BridgedConformance conformance) const {
+  swift::ProtocolConformanceRef ref = conformance.unbridged();
+  if (!ref.isConcrete()) {
+    return {nullptr};
+  }
+  return {context->getModule()->lookUpWitnessTable(ref.getConcrete())};
+}
+
+bool BridgedContext::calleesAreStaticallyKnowable(BridgedDeclRef method) const {
+  return swift::calleesAreStaticallyKnowable(*context->getModule(), method.unbridged());
+}
+
+BridgedWitnessTable BridgedContext::createSpecializedWitnessTable(BridgedLinkage linkage,
+                                                           bool serialized,
+                                                           BridgedConformance conformance,
+                                                           BridgedArrayRef bridgedEntries) const {
+  llvm::SmallVector<swift::SILWitnessTable::Entry, 8> entries;
+  for (const BridgedWitnessTableEntry &e : bridgedEntries.unbridged<BridgedWitnessTableEntry>()) {
+    entries.push_back(e.unbridged());
+  }
+  return {swift::SILWitnessTable::create(*context->getModule(), (swift::SILLinkage)linkage,
+                                         serialized ? swift::IsSerialized : swift::IsNotSerialized,
+                                         conformance.unbridged().getConcrete(),
+                                         entries, {}, /*specialized=*/true)};
+}
+
+BridgedVTable BridgedContext::createSpecializedVTable(BridgedType classType,
+                                                          bool serialized,
+                                                          BridgedArrayRef bridgedEntries) const {
+  llvm::SmallVector<swift::SILVTableEntry, 8> entries;
+  for (const BridgedVTableEntry &e : bridgedEntries.unbridged<BridgedVTableEntry>()) {
+    entries.push_back(e.unbridged());
+  }
+  swift::SILType classTy = classType.unbridged();
+  return {swift::SILVTable::create(*context->getModule(),
+                                   classTy.getClassOrBoundGenericClass(), classTy,
+                                   serialized ? swift::IsSerialized : swift::IsNotSerialized,
+                                   entries)};
+}
+
+BridgedBasicBlock BridgedContext::splitBlockBefore(BridgedInstruction bridgedInst) const {
+  auto *block = bridgedInst.unbridged()->getParent();
+  return {block->split(bridgedInst.unbridged()->getIterator())};
+}
+
+BridgedBasicBlock BridgedContext::splitBlockAfter(BridgedInstruction bridgedInst) const {
+  auto *block = bridgedInst.unbridged()->getParent();
+  return {block->split(std::next(bridgedInst.unbridged()->getIterator()))};
+}
+
+BridgedBasicBlock BridgedContext::createBlockAfter(BridgedBasicBlock bridgedBlock) const {
+  swift::SILBasicBlock *block = bridgedBlock.unbridged();
+  return {block->getParent()->createBasicBlockAfter(block)};
+}
+
+BridgedBasicBlock BridgedContext::appendBlock(BridgedFunction bridgedFunction) const {
+  return {bridgedFunction.getFunction()->createBasicBlock()};
+}
+
+void BridgedContext::eraseInstruction(BridgedInstruction inst, bool salvageDebugInfo) const {
+  context->eraseInstruction(inst.unbridged(), salvageDebugInfo);
+}
+
+void BridgedContext::eraseBlock(BridgedBasicBlock block) const {
+  block.unbridged()->eraseFromParent();
+}
+
+void BridgedContext::moveInstructionBefore(BridgedInstruction inst, BridgedInstruction beforeInst) {
+  swift::SILBasicBlock::moveInstruction(inst.unbridged(), beforeInst.unbridged());
+}
+
+void BridgedContext::copyInstructionBefore(BridgedInstruction inst, BridgedInstruction beforeInst) {
+  inst.unbridged()->clone(beforeInst.unbridged());
+}
+
+OptionalBridgedFunction BridgedContext::lookupStdlibFunction(BridgedStringRef name) const {
+  return {context->lookupStdlibFunction(name.unbridged())};
+}
+
+void BridgedContext::SSAUpdater_initialize(BridgedFunction function, BridgedType type,
+                                           BridgedValue::Ownership ownership) const {
+  context->initializeSSAUpdater(function.getFunction(), type.unbridged(), BridgedValue::unbridge(ownership));
+}
+
+void BridgedContext::SSAUpdater_addAvailableValue(BridgedBasicBlock block, BridgedValue value) const {
+  context->SSAUpdater_addAvailableValue(block.unbridged(), value.getSILValue());
+}
+
+BridgedValue BridgedContext::SSAUpdater_getValueAtEndOfBlock(BridgedBasicBlock block) const {
+  return {context->SSAUpdater_getValueAtEndOfBlock(block.unbridged())};
+}
+
+BridgedValue BridgedContext::SSAUpdater_getValueInMiddleOfBlock(BridgedBasicBlock block) const {
+  return {context->SSAUpdater_getValueInMiddleOfBlock(block.unbridged())};
+}
+
+SwiftInt BridgedContext::SSAUpdater_getNumInsertedPhis() const {
+  return (SwiftInt)context->SSAUpdater_getInsertedPhis().size();
+}
+
+BridgedValue BridgedContext::SSAUpdater_getInsertedPhi(SwiftInt idx) const {
+  return {context->SSAUpdater_getInsertedPhis()[idx]};
+}
+
+BridgedBasicBlockSet BridgedContext::allocBasicBlockSet() const {
+  return {context->allocBlockSet()};
+}
+
+void BridgedContext::freeBasicBlockSet(BridgedBasicBlockSet set) const {
+  context->freeBlockSet(set.set);
+}
+
+BridgedNodeSet BridgedContext::allocNodeSet() const {
+  return {context->allocNodeSet()};
+}
+
+void BridgedContext::freeNodeSet(BridgedNodeSet set) const {
+  context->freeNodeSet(set.set);
+}
+
+BridgedOperandSet BridgedContext::allocOperandSet() const {
+  return {context->allocOperandSet()};
+}
+
+void BridgedContext::freeOperandSet(BridgedOperandSet set) const {
+  context->freeOperandSet(set.set);
+}
+
+SwiftInt BridgedContext::Slab::getCapacity() {
+  return (SwiftInt)swift::FixedSizeSlabPayload::capacity;
+}
+
+BridgedContext::Slab::Slab(swift::FixedSizeSlab * _Nullable slab) {
+  if (slab) {
+    data = slab;
+    assert((void *)data == slab->dataFor<void>());
+  }
+}
+
+swift::FixedSizeSlab * _Nullable BridgedContext::Slab::getSlab() const {
+  if (data)
+    return static_cast<swift::FixedSizeSlab *>(data);
+  return nullptr;
+}
+
+BridgedContext::Slab BridgedContext::Slab::getNext() const {
+  return &*std::next(getSlab()->getIterator());
+}
+
+BridgedContext::Slab BridgedContext::Slab::getPrevious() const {
+  return &*std::prev(getSlab()->getIterator());
+}
+
+BridgedContext::Slab BridgedContext::allocSlab(Slab afterSlab) const {
+  return context->allocSlab(afterSlab.getSlab());
+}
+
+BridgedContext::Slab BridgedContext::freeSlab(Slab slab) const {
+  return context->freeSlab(slab.getSlab());
+}
+
 SWIFT_END_NULLABILITY_ANNOTATIONS
 
 #endif
diff --git a/include/swift/SIL/SILBuilder.h b/include/swift/SIL/SILBuilder.h
index bb69b89228fa0..aa928be7301aa 100644
--- a/include/swift/SIL/SILBuilder.h
+++ b/include/swift/SIL/SILBuilder.h
@@ -22,6 +22,7 @@
 #include "swift/SIL/SILInstruction.h"
 #include "swift/SIL/SILModule.h"
 #include "swift/SIL/SILUndef.h"
+#include "swift/SIL/AbstractionPattern.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/StringExtras.h"
 #include <type_traits>
@@ -209,7 +210,8 @@ class SILBuilder {
 
   TypeExpansionContext getTypeExpansionContext() const {
     if (!F)
-      return TypeExpansionContext::minimal();
+      return TypeExpansionContext::maximal(getModule().getSwiftModule(),
+                                           getModule().isWholeModule());
     return TypeExpansionContext(getFunction());
   }
 
@@ -222,15 +224,10 @@ class SILBuilder {
   }
   ASTContext &getASTContext() const { return getModule().getASTContext(); }
   const Lowering::TypeLowering &getTypeLowering(SILType T) const {
-
-    auto expansion = TypeExpansionContext::maximal(getModule().getSwiftModule(),
-                                                   getModule().isWholeModule());
-    // If there's no current SILFunction, we're inserting into a global
-    // variable initializer.
-    if (F) {
-      expansion = TypeExpansionContext(getFunction());
-    }
-    return getModule().Types.getTypeLowering(T, expansion);
+    return getModule().Types.getTypeLowering(T, getTypeExpansionContext());
+  }
+  SILTypeProperties getTypeProperties(SILType T) const {
+    return getModule().Types.getTypeProperties(T, getTypeExpansionContext());
   }
 
   void setCurrentDebugScope(const SILDebugScope *DS) { CurDebugScope = DS; }
@@ -283,6 +280,14 @@ class SILBuilder {
     return false;
   }
 
+  /// If we have a SILFunction, return true if it has a ManualOwnership
+  /// PerformanceConstraint, which corresponds to an attribute on the FuncDecl.
+  bool hasManualOwnershipAttr() const {
+    if (F)
+      return F->getPerfConstraints() == PerformanceConstraints::ManualOwnership;
+    return false;
+  }
+
   //===--------------------------------------------------------------------===//
   // Insertion Point Management
   //===--------------------------------------------------------------------===//
@@ -715,10 +720,10 @@ class SILBuilder {
   IntegerLiteralInst *createIntegerLiteral(IntegerLiteralExpr *E);
 
   IntegerLiteralInst *createIntegerLiteral(SILLocation Loc, SILType Ty,
-                                           intmax_t Value) {
-    return insert(
-        IntegerLiteralInst::create(getSILDebugLocation(Loc), Ty, Value,
-                                   getModule()));
+                                           intmax_t Value,
+                                           bool treatAsSigned = false) {
+    return insert(IntegerLiteralInst::create(
+        getSILDebugLocation(Loc), Ty, Value, treatAsSigned, getModule()));
   }
   IntegerLiteralInst *createIntegerLiteral(SILLocation Loc, SILType Ty,
                                            const APInt &Value) {
@@ -975,25 +980,13 @@ class SILBuilder {
                                  Qualifier));
   }
 
-  AssignByWrapperInst *createAssignByWrapper(SILLocation Loc, SILValue Src,
-                                             SILValue Dest,
-                                             SILValue Initializer,
-                                             SILValue Setter,
-                                             AssignByWrapperInst::Mode mode) {
-    return insert(new (getModule()) AssignByWrapperInst(
-        getSILDebugLocation(Loc), Src, Dest, Initializer, Setter, mode));
-  }
-
-  AssignOrInitInst *createAssignOrInit(SILLocation Loc,
-                                       VarDecl *Property,
-                                       SILValue Self,
-                                       SILValue Src,
-                                       SILValue Initializer,
-                                       SILValue Setter,
+  AssignOrInitInst *createAssignOrInit(SILLocation Loc, VarDecl *Property,
+                                       SILValue SelfOrLocal, SILValue Src,
+                                       SILValue Initializer, SILValue Setter,
                                        AssignOrInitInst::Mode Mode) {
-    return insert(new (getModule())
-                      AssignOrInitInst(getSILDebugLocation(Loc), Property, Self,
-                                       Src, Initializer, Setter, Mode));
+    return insert(new (getModule()) AssignOrInitInst(
+        getSILDebugLocation(Loc), Property, SelfOrLocal, Src, Initializer,
+        Setter, Mode));
   }
 
   StoreBorrowInst *createStoreBorrow(SILLocation Loc, SILValue Src,
@@ -1553,33 +1546,33 @@ class SILBuilder {
 
   UnconditionalCheckedCastInst *
   createUnconditionalCheckedCast(SILLocation Loc,
-                                 CastingIsolatedConformances isolatedConformances,
+                                 CheckedCastInstOptions options,
                                  SILValue op,
                                  SILType destLoweredTy,
                                  CanType destFormalTy) {
-    return createUnconditionalCheckedCast(Loc, isolatedConformances, op,
+    return createUnconditionalCheckedCast(Loc, options, op,
                                           destLoweredTy, destFormalTy,
                                           op->getOwnershipKind());
   }
 
   UnconditionalCheckedCastInst *
   createUnconditionalCheckedCast(SILLocation Loc,
-                                 CastingIsolatedConformances isolatedConformances,
+                                 CheckedCastInstOptions options,
                                  SILValue op,
                                  SILType destLoweredTy, CanType destFormalTy,
                                  ValueOwnershipKind forwardingOwnershipKind) {
     return insert(UnconditionalCheckedCastInst::create(
-        getSILDebugLocation(Loc), isolatedConformances, op, destLoweredTy,
+        getSILDebugLocation(Loc), options, op, destLoweredTy,
         destFormalTy, getFunction(), forwardingOwnershipKind));
   }
 
   UnconditionalCheckedCastAddrInst *
   createUnconditionalCheckedCastAddr(SILLocation Loc,
-                                     CastingIsolatedConformances isolatedConformances,
+                                     CheckedCastInstOptions options,
                                      SILValue src, CanType sourceFormalType,
                                      SILValue dest, CanType targetFormalType) {
     return insert(UnconditionalCheckedCastAddrInst::create(
-        getSILDebugLocation(Loc), isolatedConformances, src, sourceFormalType,
+        getSILDebugLocation(Loc), options, src, sourceFormalType,
         dest, targetFormalType, getFunction()));
   }
 
@@ -1682,7 +1675,7 @@ class SILBuilder {
   StructInst *createStruct(SILLocation Loc, SILType Ty,
                            ArrayRef<SILValue> Elements,
                            ValueOwnershipKind forwardingOwnershipKind) {
-    ASSERT(isLoadableOrOpaque(Ty));
+    ASSERT(isLoadableOrOpaque(Ty) || isInsertingIntoGlobal());
     return insert(StructInst::create(getSILDebugLocation(Loc), Ty, Elements,
                                      getModule(), forwardingOwnershipKind));
   }
@@ -1727,7 +1720,8 @@ class SILBuilder {
   EnumInst *createEnum(SILLocation Loc, SILValue Operand,
                        EnumElementDecl *Element, SILType Ty,
                        ValueOwnershipKind forwardingOwnershipKind) {
-    ASSERT(isLoadableOrOpaque(Ty));
+    ASSERT(isLoadableOrOpaque(Ty) ||
+           (isInsertingIntoGlobal() && getTypeLowering(Ty).isFixedABI()));
     // Assert that this works and does not crash.
     (void)getModule().getCaseIndex(Element);
 
@@ -1923,6 +1917,15 @@ class SILBuilder {
     return createStructElementAddr(Loc, Operand, Field, ResultTy);
   }
 
+  VectorBaseAddrInst *
+  createVectorBaseAddr(SILLocation loc, SILValue vector) {
+    auto arrayTy = vector->getType().getAs<BuiltinFixedArrayType>();
+    ASSERT(arrayTy && "operand of vector_extract must be a builtin array type");
+    auto elemtTy = getFunction().getLoweredType(Lowering::AbstractionPattern::getOpaque(), arrayTy->getElementType());
+    return insert(new (getModule()) VectorBaseAddrInst(
+        getSILDebugLocation(loc), vector, elemtTy.getAddressType()));
+  }
+
   RefElementAddrInst *createRefElementAddr(SILLocation Loc, SILValue Operand,
                                            VarDecl *Field, SILType ResultTy,
                                            bool IsImmutable = false) {
@@ -2336,7 +2339,7 @@ class SILBuilder {
                       FixLifetimeInst(getSILDebugLocation(Loc), Operand));
   }
   void emitFixLifetime(SILLocation Loc, SILValue Operand) {
-    if (getTypeLowering(Operand->getType()).isTrivial())
+    if (getTypeProperties(Operand->getType()).isTrivial())
       return;
     createFixLifetime(Loc, Operand);
   }
@@ -2383,6 +2386,11 @@ class SILBuilder {
     return insert(new (getModule()) EndCOWMutationInst(getSILDebugLocation(Loc),
                                                   operand, keepUnique));
   }
+  EndCOWMutationAddrInst *createEndCOWMutationAddr(SILLocation Loc,
+                                                   SILValue operand) {
+    return insert(new (getModule()) EndCOWMutationAddrInst(
+        getSILDebugLocation(Loc), operand));
+  }
   DestroyNotEscapedClosureInst *createDestroyNotEscapedClosure(SILLocation Loc,
                                                  SILValue operand,
                                                  unsigned VerificationType) {
@@ -2764,7 +2772,7 @@ class SILBuilder {
 
   CheckedCastBranchInst *
   createCheckedCastBranch(SILLocation Loc, bool isExact,
-                          CastingIsolatedConformances isolatedConformances,
+                          CheckedCastInstOptions options,
                           SILValue op,
                           CanType srcFormalTy, SILType destLoweredTy,
                           CanType destFormalTy, SILBasicBlock *successBB,
@@ -2774,7 +2782,7 @@ class SILBuilder {
 
   CheckedCastBranchInst *
   createCheckedCastBranch(SILLocation Loc, bool isExact,
-                          CastingIsolatedConformances isolatedConformances,
+                          CheckedCastInstOptions options,
                           SILValue op,
                           CanType srcFormalTy, SILType destLoweredTy,
                           CanType destFormalTy, SILBasicBlock *successBB, 
@@ -2785,7 +2793,7 @@ class SILBuilder {
 
   CheckedCastAddrBranchInst *
   createCheckedCastAddrBranch(SILLocation Loc,
-                              CastingIsolatedConformances isolatedConformances,
+                              CheckedCastInstOptions options,
                               CastConsumptionKind consumption,
                               SILValue src, CanType sourceFormalType,
                               SILValue dest, CanType targetFormalType,
@@ -2794,7 +2802,7 @@ class SILBuilder {
                               ProfileCounter Target1Count = ProfileCounter(),
                               ProfileCounter Target2Count = ProfileCounter()) {
     return insertTerminator(CheckedCastAddrBranchInst::create(
-        getSILDebugLocation(Loc), isolatedConformances, consumption, src,
+        getSILDebugLocation(Loc), options, consumption, src,
         sourceFormalType, dest, targetFormalType, successBB, failureBB,
         Target1Count, Target2Count, getFunction()));
   }
@@ -2813,9 +2821,9 @@ class SILBuilder {
   /// instruction, it returns it, otherwise it returns null.
   DestroyAddrInst *emitDestroyAddrAndFold(SILLocation Loc, SILValue Operand) {
     auto U = emitDestroyAddr(Loc, Operand);
-    if (U.isNull() || !U.is<DestroyAddrInst *>())
+    if (U.isNull() || !isa<DestroyAddrInst *>(U))
       return nullptr;
-    return U.get<DestroyAddrInst *>();
+    return cast<DestroyAddrInst *>(U);
   }
 
   /// Perform a strong_release instruction at the current location, attempting
@@ -2829,7 +2837,7 @@ class SILBuilder {
       return nullptr;
     if (auto *SRI = U.dyn_cast<StrongReleaseInst *>())
       return SRI;
-    U.get<StrongRetainInst *>()->eraseFromParent();
+    cast<StrongRetainInst *>(U)->eraseFromParent();
     return nullptr;
   }
 
@@ -2846,7 +2854,7 @@ class SILBuilder {
       return nullptr;
     if (auto *RVI = U.dyn_cast<ReleaseValueInst *>())
       return RVI;
-    U.get<RetainValueInst *>()->eraseFromParent();
+    cast<RetainValueInst *>(U)->eraseFromParent();
     return nullptr;
   }
 
@@ -2863,7 +2871,7 @@ class SILBuilder {
       return nullptr;
     if (auto *DVI = U.dyn_cast<DestroyValueInst *>())
       return DVI;
-    auto *CVI = U.get<CopyValueInst *>();
+    auto *CVI = cast<CopyValueInst *>(U);
     CVI->replaceAllUsesWith(CVI->getOperand());
     CVI->eraseFromParent();
     return nullptr;
@@ -3172,7 +3180,7 @@ class SILBuilder {
     if (!SILModuleConventions(M).useLoweredAddresses())
       return true;
 
-    return getTypeLowering(Ty).isLoadable();
+    return getTypeProperties(Ty).isLoadable();
   }
 
   void appendOperandTypeName(SILType OpdTy, llvm::SmallString<16> &Name) {
@@ -3377,10 +3385,10 @@ class SavedInsertionPointRAII {
   ~SavedInsertionPointRAII() {
     if (savedInsertionPoint.isNull()) {
       builder.clearInsertionPoint();
-    } else if (savedInsertionPoint.is<SILInstruction *>()) {
-      builder.setInsertionPoint(savedInsertionPoint.get<SILInstruction *>());
+    } else if (isa<SILInstruction *>(savedInsertionPoint)) {
+      builder.setInsertionPoint(cast<SILInstruction *>(savedInsertionPoint));
     } else {
-      builder.setInsertionPoint(savedInsertionPoint.get<SILBasicBlock *>());
+      builder.setInsertionPoint(cast<SILBasicBlock *>(savedInsertionPoint));
     }
   }
 };
diff --git a/include/swift/SIL/SILCloner.h b/include/swift/SIL/SILCloner.h
index 080652cb4aa1a..8efd611a50e34 100644
--- a/include/swift/SIL/SILCloner.h
+++ b/include/swift/SIL/SILCloner.h
@@ -80,20 +80,24 @@ struct SubstitutionMapWithLocalArchetypes {
     return Type(type);
   }
 
-  ProtocolConformanceRef operator()(CanType origType,
-                                    Type substType,
+  ProtocolConformanceRef operator()(InFlightSubstitution &IFS,
+                                    Type origType,
                                     ProtocolDecl *proto) {
-    if (isa<LocalArchetypeType>(origType))
-      return swift::lookupConformance(substType, proto);
+    if (origType->is<LocalArchetypeType>())
+      return swift::lookupConformance(origType.subst(IFS), proto);
 
-    if (isa<PrimaryArchetypeType>(origType) ||
-        isa<PackArchetypeType>(origType))
-      origType = origType->mapTypeOutOfContext()->getCanonicalType();
+    if (SubsMap) {
+      if (origType->is<PrimaryArchetypeType>() ||
+          origType->is<PackArchetypeType>()) {
+        origType = origType->mapTypeOutOfContext();
+      }
 
-    if (SubsMap)
-      return SubsMap->lookupConformance(origType, proto);
+      return SubsMap->lookupConformance(
+        origType->getCanonicalType(), proto);
+    }
 
-    return ProtocolConformanceRef::forAbstract(substType, proto);
+    return ProtocolConformanceRef::forAbstract(
+      origType.subst(IFS), proto);
   }
 
   void dump(llvm::raw_ostream &out) const {
@@ -213,6 +217,20 @@ class SILCloner : protected SILInstructionVisitor<ImplClass> {
                          ArrayRef<SILValue> entryArgs,
                          bool replaceOriginalFunctionInPlace = false);
 
+  void cloneFunctionBody(SILFunction *F);
+
+  /// Clone all blocks in this function and all instructions in those
+  /// blocks.
+  ///
+  /// This is used to clone an entire function without mutating the original
+  /// function.
+  ///
+  /// The new function is expected to be completely empty. Clone the entry
+  /// blocks arguments here. The cloned arguments become the inputs to the
+  /// general SILCloner, which expects the new entry block to be ready to emit
+  /// instructions into.
+  void cloneFunction(SILFunction *origF);
+
   /// The same as clone function body, except the caller can provide a callback
   /// that allows for an entry arg to be assigned to a custom old argument. This
   /// is useful if one re-arranges parameters when converting from inout to out.
@@ -409,32 +427,16 @@ class SILCloner : protected SILInstructionVisitor<ImplClass> {
       VarInfo->Scope = getOpScope(VarInfo->Scope);
   }
 
-  ProtocolConformanceRef getOpConformance(Type ty,
-                                          ProtocolConformanceRef conformance) {
-    auto substConf = asImpl().remapConformance(ty, conformance);
-
-#ifndef NDEBUG
-    if (substConf.isInvalid()) {
-      llvm::errs() << "Invalid conformance in SIL cloner:\n";
-      Functor.dump(llvm::errs());
-      llvm::errs() << "\nconformance:\n";
-      conformance.dump(llvm::errs());
-      llvm::errs() << "\noriginal type:\n";
-      ty.dump(llvm::errs());
-      abort();
-    }
-#endif
-
-    return substConf;
+  ProtocolConformanceRef getOpConformance(ProtocolConformanceRef conformance) {
+    return asImpl().remapConformance(conformance);
   }
 
   ArrayRef<ProtocolConformanceRef>
-  getOpConformances(Type ty,
-                    ArrayRef<ProtocolConformanceRef> conformances) {
+  getOpConformances(ArrayRef<ProtocolConformanceRef> conformances) {
     SmallVector<ProtocolConformanceRef, 4> newConformances;
     for (auto conformance : conformances)
-      newConformances.push_back(getOpConformance(ty, conformance));
-    return ty->getASTContext().AllocateCopy(newConformances);
+      newConformances.push_back(getOpConformance(conformance));
+    return getBuilder().getASTContext().AllocateCopy(newConformances);
   }
 
   bool isValueCloned(SILValue OrigValue) const {
@@ -558,28 +560,36 @@ class SILCloner : protected SILInstructionVisitor<ImplClass> {
     return ty;
   }
 
-  ProtocolConformanceRef remapConformance(Type Ty, ProtocolConformanceRef C) {
-    if (Functor.SubsMap || Ty->hasLocalArchetype()) {
+  ProtocolConformanceRef remapConformance(ProtocolConformanceRef conformance) {
+    auto substConf = conformance;
+
+    if (Functor.SubsMap || substConf.getType()->hasLocalArchetype()) {
       SubstOptions options = SubstFlags::SubstitutePrimaryArchetypes;
       if (Functor.hasLocalArchetypes())
         options |= SubstFlags::SubstituteLocalArchetypes;
 
-      C = C.subst(Ty, Functor, Functor, options);
-      if (asImpl().shouldSubstOpaqueArchetypes())
-        Ty = Ty.subst(Functor, Functor, options);
+      substConf = substConf.subst(Functor, Functor, options);
+    }
+
+    if (substConf.isInvalid()) {
+      ABORT([&](auto &out) {
+        out << "Invalid substituted conformance in SIL cloner:\n";
+        Functor.dump(out);
+        out << "\noriginal conformance:\n";
+        conformance.dump(out);
+      });
     }
 
     if (asImpl().shouldSubstOpaqueArchetypes()) {
       auto context = getBuilder().getTypeExpansionContext();
 
-      if (!Ty->hasOpaqueArchetype() ||
-          !context.shouldLookThroughOpaqueTypeArchetypes())
-        return C;
-
-      return substOpaqueTypesWithUnderlyingTypes(C, Ty, context);
+      if (substConf.getType()->hasOpaqueArchetype() &&
+          context.shouldLookThroughOpaqueTypeArchetypes()) {
+        return substOpaqueTypesWithUnderlyingTypes(substConf, context);
+      }
     }
 
-    return C;
+    return substConf;
   }
 
   SubstitutionMap remapSubstitutionMap(SubstitutionMap Subs) {
@@ -599,11 +609,7 @@ class SILCloner : protected SILInstructionVisitor<ImplClass> {
           !context.shouldLookThroughOpaqueTypeArchetypes())
         return Subs;
 
-      ReplaceOpaqueTypesWithUnderlyingTypes replacer(
-        context.getContext(), context.getResilienceExpansion(),
-        context.isWholeModuleContext());
-      return Subs.subst(replacer, replacer,
-                        SubstFlags::SubstituteOpaqueArchetypes);
+      return substOpaqueTypesWithUnderlyingTypes(Subs, context);
     }
 
     return Subs;
@@ -712,32 +718,6 @@ class SILFunctionCloner : public SILClonerWithScopes<SILFunctionCloner> {
 
 public:
   SILFunctionCloner(SILFunction *newF) : SILClonerWithScopes(*newF) {}
-
-  /// Clone all blocks in this function and all instructions in those
-  /// blocks.
-  ///
-  /// This is used to clone an entire function without mutating the original
-  /// function.
-  ///
-  /// The new function is expected to be completely empty. Clone the entry
-  /// blocks arguments here. The cloned arguments become the inputs to the
-  /// general SILCloner, which expects the new entry block to be ready to emit
-  /// instructions into.
-  void cloneFunction(SILFunction *origF) {
-    SILFunction *newF = &Builder.getFunction();
-
-    auto *newEntryBB = newF->createBasicBlock();
-    newEntryBB->cloneArgumentList(origF->getEntryBlock());
-
-    // Copy the new entry block arguments into a separate vector purely to
-    // resolve the type mismatch between SILArgument* and SILValue.
-    SmallVector<SILValue, 8> entryArgs;
-    entryArgs.reserve(newF->getArguments().size());
-    llvm::transform(newF->getArguments(), std::back_inserter(entryArgs),
-                    [](SILArgument *arg) -> SILValue { return arg; });
-
-    SuperTy::cloneFunctionBody(origF, newEntryBB, entryArgs);
-  }
 };
 
 template<typename ImplClass>
@@ -858,18 +838,13 @@ void SILCloner<ImplClass>::cloneFunctionBody(SILFunction *F,
 }
 
 template <typename ImplClass>
-void SILCloner<ImplClass>::cloneFunctionBody(
-    SILFunction *F, SILBasicBlock *clonedEntryBB, ArrayRef<SILValue> entryArgs,
-    llvm::function_ref<SILValue(SILValue)> entryArgIndexToOldArgIndex) {
-  assert(F != clonedEntryBB->getParent() && "Must clone into a new function.");
-  assert(BBMap.empty() && "This API does not allow clients to map blocks.");
-  assert(ValueMap.empty() && "Stale ValueMap.");
+void SILCloner<ImplClass>::cloneFunctionBody(SILFunction *F) {
+  assert(!Builder.getFunction().empty() && "Expect the entry block to already be created");
 
-  assert(entryArgs.size() == F->getArguments().size());
-  for (unsigned i = 0, e = entryArgs.size(); i != e; ++i) {
-    ValueMap[entryArgIndexToOldArgIndex(entryArgs[i])] = entryArgs[i];
-  }
+  assert(F != &Builder.getFunction() && "Must clone into a new function.");
+  assert(BBMap.empty() && "This API does not allow clients to map blocks.");
 
+  SILBasicBlock *clonedEntryBB = Builder.getFunction().getEntryBlock();
   BBMap.insert(std::make_pair(&*F->begin(), clonedEntryBB));
 
   Builder.setInsertionPoint(clonedEntryBB);
@@ -880,6 +855,44 @@ void SILCloner<ImplClass>::cloneFunctionBody(
   commonFixUp(F);
 }
 
+template <typename ImplClass>
+void SILCloner<ImplClass>::cloneFunction(SILFunction *origF) {
+  SILFunction *newF = &Builder.getFunction();
+  if (!newF->empty()) {
+    cloneFunctionBody(origF);
+    return;
+  }
+
+  auto *newEntryBB = newF->createBasicBlock();
+
+  for (auto *funcArg : origF->begin()->getSILFunctionArguments()) {
+    auto *newArg = newEntryBB->insertFunctionArgument(newEntryBB->getNumArguments(),
+      asImpl().remapType(funcArg->getType()), funcArg->getOwnershipKind(), funcArg->getDecl());
+    newArg->copyFlags(funcArg);
+  }
+
+  // Copy the new entry block arguments into a separate vector purely to
+  // resolve the type mismatch between SILArgument* and SILValue.
+  SmallVector<SILValue, 8> entryArgs;
+  entryArgs.reserve(newF->getArguments().size());
+  llvm::transform(newF->getArguments(), std::back_inserter(entryArgs),
+                  [](SILArgument *arg) -> SILValue { return arg; });
+
+  cloneFunctionBody(origF, newEntryBB, entryArgs);
+}
+
+template <typename ImplClass>
+void SILCloner<ImplClass>::cloneFunctionBody(
+    SILFunction *F, SILBasicBlock *clonedEntryBB, ArrayRef<SILValue> entryArgs,
+    llvm::function_ref<SILValue(SILValue)> entryArgIndexToOldArgIndex) {
+  assert(ValueMap.empty() && "Stale ValueMap.");
+  assert(entryArgs.size() == F->getArguments().size());
+  for (unsigned i = 0, e = entryArgs.size(); i != e; ++i) {
+    ValueMap[entryArgIndexToOldArgIndex(entryArgs[i])] = entryArgs[i];
+  }
+  cloneFunctionBody(F);
+}
+
 template<typename ImplClass>
 void SILCloner<ImplClass>::clonePhiArgs(SILBasicBlock *oldBB) {
   auto *mappedBB = BBMap[oldBB];
@@ -1135,8 +1148,7 @@ SILCloner<ImplClass>::visitAllocExistentialBoxInst(
   auto origExistentialType = Inst->getExistentialType();
   auto origFormalType = Inst->getFormalConcreteType();
 
-  auto conformances = getOpConformances(origFormalType,
-                                        Inst->getConformances());
+  auto conformances = getOpConformances(Inst->getConformances());
 
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
   recordClonedInstruction(
@@ -1531,27 +1543,14 @@ void SILCloner<ImplClass>::visitAssignInst(AssignInst *Inst) {
                                       Inst->getOwnershipQualifier()));
 }
 
-template <typename ImplClass>
-void SILCloner<ImplClass>::visitAssignByWrapperInst(AssignByWrapperInst *Inst) {
-  getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
-  recordClonedInstruction(
-      Inst, getBuilder().createAssignByWrapper(
-                getOpLocation(Inst->getLoc()),
-                getOpValue(Inst->getSrc()), getOpValue(Inst->getDest()),
-                getOpValue(Inst->getInitializer()),
-                getOpValue(Inst->getSetter()), Inst->getMode()));
-}
-
 template <typename ImplClass>
 void SILCloner<ImplClass>::visitAssignOrInitInst(AssignOrInitInst *Inst) {
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
   recordClonedInstruction(
       Inst, getBuilder().createAssignOrInit(
-                getOpLocation(Inst->getLoc()),
-                Inst->getProperty(),
-                getOpValue(Inst->getSelf()),
-                getOpValue(Inst->getSrc()),
-                getOpValue(Inst->getInitializer()),
+                getOpLocation(Inst->getLoc()), Inst->getProperty(),
+                getOpValue(Inst->getSelfOrLocalOperand()),
+                getOpValue(Inst->getSrc()), getOpValue(Inst->getInitializer()),
                 getOpValue(Inst->getSetter()), Inst->getMode()));
 }
 
@@ -1712,6 +1711,16 @@ template<typename ImplClass>
 void
 SILCloner<ImplClass>::visitCopyAddrInst(CopyAddrInst *Inst) {
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
+  // When cloning into a function using manual ownership, convert to explicit
+  // copies, in order to preserve the local nature of the perf constraint.
+  if (getBuilder().hasManualOwnershipAttr() && getBuilder().hasOwnership()) {
+    recordClonedInstruction(
+      Inst, getBuilder().createExplicitCopyAddr(
+                getOpLocation(Inst->getLoc()), getOpValue(Inst->getSrc()),
+                getOpValue(Inst->getDest()), Inst->isTakeOfSrc(),
+                Inst->isInitializationOfDest()));
+    return;
+  }
   recordClonedInstruction(
       Inst, getBuilder().createCopyAddr(
                 getOpLocation(Inst->getLoc()), getOpValue(Inst->getSrc()),
@@ -2032,7 +2041,7 @@ SILCloner<ImplClass>::visitUnconditionalCheckedCastInst(
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
   recordClonedInstruction(Inst,
                           getBuilder().createUnconditionalCheckedCast(
-                              OpLoc, Inst->getIsolatedConformances(), OpValue,
+                              OpLoc, Inst->getCheckedCastOptions(), OpValue,
                               OpLoweredType, OpFormalType,
                               getBuilder().hasOwnership()
                                   ? Inst->getForwardingOwnershipKind()
@@ -2051,7 +2060,7 @@ SILCloner<ImplClass>::visitUnconditionalCheckedCastAddrInst(
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
   recordClonedInstruction(Inst,
                           getBuilder().createUnconditionalCheckedCastAddr(
-                              OpLoc, Inst->getIsolatedConformances(),
+                              OpLoc, Inst->getCheckedCastOptions(),
                               SrcValue, SrcType, DestValue, TargetType));
 }
 
@@ -2106,6 +2115,15 @@ void SILCloner<ImplClass>::visitCopyValueInst(CopyValueInst *Inst) {
     return recordFoldedValue(Inst, newValue);
   }
 
+  // When cloning into a function using manual ownership, convert to explicit
+  // copies, in order to preserve the local nature of the perf constraint.
+  if (getBuilder().hasManualOwnershipAttr() && getBuilder().hasOwnership()) {
+    recordClonedInstruction(
+      Inst, getBuilder().createExplicitCopyValue(getOpLocation(Inst->getLoc()),
+                                         getOpValue(Inst->getOperand())));
+    return;
+  }
+
   recordClonedInstruction(
       Inst, getBuilder().createCopyValue(getOpLocation(Inst->getLoc()),
                                          getOpValue(Inst->getOperand())));
@@ -2553,6 +2571,16 @@ SILCloner<ImplClass>::visitStructElementAddrInst(StructElementAddrInst *Inst) {
                 Inst->getField(), getOpType(Inst->getType())));
 }
 
+template<typename ImplClass>
+void
+SILCloner<ImplClass>::visitVectorBaseAddrInst(VectorBaseAddrInst *Inst) {
+  getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
+  recordClonedInstruction(
+      Inst, getBuilder().createVectorBaseAddr(
+                getOpLocation(Inst->getLoc()),
+                getOpValue(Inst->getVector())));
+}
+
 template<typename ImplClass>
 void
 SILCloner<ImplClass>::visitRefElementAddrInst(RefElementAddrInst *Inst) {
@@ -2659,29 +2687,28 @@ SILCloner<ImplClass>::visitObjCSuperMethodInst(ObjCSuperMethodInst *Inst) {
 template<typename ImplClass>
 void
 SILCloner<ImplClass>::visitWitnessMethodInst(WitnessMethodInst *Inst) {
-  auto lookupType = Inst->getLookupType();
-  auto conformance = getOpConformance(lookupType, Inst->getConformance());
-  auto newLookupType = getOpASTType(lookupType);
+  auto conformance = getOpConformance(Inst->getConformance());
+  auto lookupType = getOpASTType(Inst->getLookupType());
 
   if (conformance.isConcrete()) {
-    CanType Ty = conformance.getConcrete()->getType()->getCanonicalType();
+    auto conformingType = conformance.getConcrete()->getType()->getCanonicalType();
 
-    if (Ty != newLookupType) {
+    if (conformingType != lookupType) {
       assert(
-          (Ty->isExactSuperclassOf(newLookupType) ||
+          (conformingType->isExactSuperclassOf(lookupType) ||
            getBuilder().getModule().Types.getLoweredRValueType(
-               getBuilder().getTypeExpansionContext(), Ty) == newLookupType) &&
+               getBuilder().getTypeExpansionContext(), conformingType) == lookupType) &&
           "Should only create upcasts for sub class.");
 
       // We use the super class as the new look up type.
-      newLookupType = Ty;
+      lookupType = conformingType;
     }
   }
 
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
   recordClonedInstruction(Inst,
                           getBuilder().createWitnessMethod(
-                              getOpLocation(Inst->getLoc()), newLookupType,
+                              getOpLocation(Inst->getLoc()), lookupType,
                               conformance, Inst->getMember(), getOpType(Inst->getType())));
 }
 
@@ -2790,8 +2817,7 @@ void
 SILCloner<ImplClass>::visitInitExistentialAddrInst(InitExistentialAddrInst *Inst) {
   CanType origFormalType = Inst->getFormalConcreteType();
 
-  auto conformances = getOpConformances(origFormalType,
-                                        Inst->getConformances());
+  auto conformances = getOpConformances(Inst->getConformances());
 
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
   recordClonedInstruction(
@@ -2806,8 +2832,7 @@ void SILCloner<ImplClass>::visitInitExistentialValueInst(
     InitExistentialValueInst *Inst) {
   CanType origFormalType = Inst->getFormalConcreteType();
 
-  auto conformances = getOpConformances(origFormalType,
-                                        Inst->getConformances());
+  auto conformances = getOpConformances(Inst->getConformances());
 
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
   recordClonedInstruction(
@@ -2821,9 +2846,7 @@ template<typename ImplClass>
 void
 SILCloner<ImplClass>::
 visitInitExistentialMetatypeInst(InitExistentialMetatypeInst *Inst) {
-  auto origFormalType = Inst->getFormalErasedObjectType();
-  auto conformances = getOpConformances(origFormalType,
-                                        Inst->getConformances());
+  auto conformances = getOpConformances(Inst->getConformances());
 
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
   recordClonedInstruction(Inst, getBuilder().createInitExistentialMetatype(
@@ -2837,8 +2860,7 @@ void
 SILCloner<ImplClass>::
 visitInitExistentialRefInst(InitExistentialRefInst *Inst) {
   CanType origFormalType = Inst->getFormalConcreteType();
-  auto conformances = getOpConformances(origFormalType,
-                                        Inst->getConformances());
+  auto conformances = getOpConformances(Inst->getConformances());
 
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
   recordClonedInstruction(
@@ -3187,6 +3209,14 @@ void SILCloner<ImplClass>::visitEndCOWMutationInst(EndCOWMutationInst *Inst) {
                         getOpValue(Inst->getOperand()), Inst->doKeepUnique()));
 }
 template <typename ImplClass>
+void SILCloner<ImplClass>::visitEndCOWMutationAddrInst(
+    EndCOWMutationAddrInst *Inst) {
+  getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
+  recordClonedInstruction(
+      Inst, getBuilder().createEndCOWMutationAddr(
+                getOpLocation(Inst->getLoc()), getOpValue(Inst->getOperand())));
+}
+template <typename ImplClass>
 void SILCloner<ImplClass>::visitDestroyNotEscapedClosureInst(
     DestroyNotEscapedClosureInst *Inst) {
   getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
@@ -3450,7 +3480,7 @@ SILCloner<ImplClass>::visitCheckedCastBranchInst(CheckedCastBranchInst *Inst) {
   recordClonedInstruction(
       Inst, getBuilder().createCheckedCastBranch(
                 getOpLocation(Inst->getLoc()), Inst->isExact(),
-                Inst->getIsolatedConformances(),
+                Inst->getCheckedCastOptions(),
                 getOpValue(Inst->getOperand()),
                 getOpASTType(Inst->getSourceFormalType()),
                 getOpType(Inst->getTargetLoweredType()),
@@ -3472,7 +3502,7 @@ void SILCloner<ImplClass>::visitCheckedCastAddrBranchInst(
   auto FalseCount = Inst->getFalseBBCount();
   recordClonedInstruction(Inst, getBuilder().createCheckedCastAddrBranch(
                                     getOpLocation(Inst->getLoc()),
-                                    Inst->getIsolatedConformances(),
+                                    Inst->getCheckedCastOptions(),
                                     Inst->getConsumptionKind(), SrcValue,
                                     SrcType, DestValue, TargetType, OpSuccBB,
                                     OpFailBB, TrueCount, FalseCount));
@@ -3532,9 +3562,7 @@ visitSwitchEnumAddrInst(SwitchEnumAddrInst *Inst) {
                                               getOpValue(Inst->getOperand()),
                                               DefaultBB, CaseBBs));
 }
-  
 
-  
 template<typename ImplClass>
 void
 SILCloner<ImplClass>::visitSelectEnumInst(SelectEnumInst *Inst) {
diff --git a/include/swift/SIL/SILConstants.h b/include/swift/SIL/SILConstants.h
index 9c829ac42322a..51cc6e3b495e9 100644
--- a/include/swift/SIL/SILConstants.h
+++ b/include/swift/SIL/SILConstants.h
@@ -737,7 +737,7 @@ struct SymbolicClosure final
                                  SymbolicValueAllocator &allocator);
 
   ArrayRef<SymbolicClosureArgument> getCaptures() const {
-    return {getTrailingObjects<SymbolicClosureArgument>(), numCaptures};
+    return getTrailingObjects(numCaptures);
   }
 
   // This is used by the llvm::TrailingObjects base class.
diff --git a/include/swift/SIL/SILContext.h b/include/swift/SIL/SILContext.h
new file mode 100644
index 0000000000000..957fa72e7eee0
--- /dev/null
+++ b/include/swift/SIL/SILContext.h
@@ -0,0 +1,130 @@
+//===--- SILContext.h -------------------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SIL_SILBRIDGINGCONTEXT_H
+#define SWIFT_SIL_SILBRIDGINGCONTEXT_H
+
+#include "swift/SIL/SILFunction.h"
+#include "swift/SIL/BasicBlockBits.h"
+#include "swift/SIL/NodeBits.h"
+#include "swift/SIL/OperandBits.h"
+
+namespace swift {
+
+class SILSSAUpdater;
+
+/// The abstract base class for the C++ implementation of Context in SwiftCompilerSources.
+/// Referenced in BridgedContext.
+///
+/// Everything which only needs SIL is directly implemented in this class.
+/// Everything which needs the SILPassManager is implemented in the derived class SwiftPassInvocation.
+///
+class SILContext {
+public:
+  enum NotificationKind : unsigned {
+    Nothing = 0,
+    Instructions = 0x1,
+    Calls = 0x2,
+    Branches = 0x4,
+    Effects = 0x8,
+    FunctionTables = 0x10
+  };
+
+protected:
+  SILContext(SILFunction *f) : function(f), mod(&f->getModule()) {}
+  SILContext(SILModule *mod) : mod(mod) {}
+
+  virtual ~SILContext();
+
+  /// The currently optimized function or null if this is the context of a module pass.
+  SILFunction *function = nullptr;
+
+  SILModule *mod = nullptr;
+
+  /// All slabs, allocated by the pass.
+  SILModule::SlabList allocatedSlabs;
+
+  static constexpr int BlockSetCapacity = SILBasicBlock::numCustomBits;
+  char blockSetStorage[sizeof(BasicBlockSet) * BlockSetCapacity];
+  bool aliveBlockSets[BlockSetCapacity];
+  int numBlockSetsAllocated = 0;
+
+  static constexpr int NodeSetCapacity = SILNode::numCustomBits;
+  char nodeSetStorage[sizeof(NodeSet) * NodeSetCapacity];
+  bool aliveNodeSets[NodeSetCapacity];
+  int numNodeSetsAllocated = 0;
+
+  static constexpr int OperandSetCapacity = Operand::numCustomBits;
+  char operandSetStorage[sizeof(OperandSet) * OperandSetCapacity];
+  bool aliveOperandSets[OperandSetCapacity];
+  int numOperandSetsAllocated = 0;
+
+  int numClonersAllocated = 0;
+
+  SILSSAUpdater *ssaUpdater = nullptr;
+  SmallVector<SILPhiArgument *, 4> insertedPhisBySSAUpdater;
+
+  /// Change notifications, collected during a pass run.
+  NotificationKind changeNotifications = NotificationKind::Nothing;
+
+  void verifyEverythingIsCleared();
+
+public:
+  SILModule *getModule() const { return mod; }
+  SILFunction *getFunction() const {
+    ASSERT(function != nullptr && "not in a function pass");
+    return function;
+  }
+
+  /// Called by the pass when changes are made to the SIL.
+  void notifyChanges(NotificationKind notification) {
+    changeNotifications = (NotificationKind)(changeNotifications | notification);
+  }
+
+  FixedSizeSlab *allocSlab(FixedSizeSlab *afterSlab);
+
+  FixedSizeSlab *freeSlab(FixedSizeSlab *slab);
+
+  BasicBlockSet *allocBlockSet();
+
+  void freeBlockSet(BasicBlockSet *set);
+
+  NodeSet *allocNodeSet();
+
+  void freeNodeSet(NodeSet *set);
+
+  OperandSet *allocOperandSet();
+
+  void freeOperandSet(OperandSet *set);
+
+  void notifyNewCloner() { numClonersAllocated++; }
+  void notifyClonerDestroyed() { numClonersAllocated--; }
+
+  virtual void eraseInstruction(SILInstruction *inst, bool salvageDebugInfo) = 0;
+  virtual SILFunction *createEmptyFunction(StringRef name, ArrayRef<SILParameterInfo> params,
+                                          bool hasSelfParam, SILFunction *fromFn) = 0;
+  virtual void moveFunctionBody(SILFunction *sourceFn, SILFunction *destFn) = 0;
+
+  virtual SILFunction *lookupStdlibFunction(StringRef name) = 0;
+
+  // The SILSSAUpdater is implemented in the Optimizer. Therefore all the APIs need to take
+  // the indirection through virtual functions to SwiftPassInvocation.
+  virtual void initializeSSAUpdater(SILFunction *function, SILType type, ValueOwnershipKind ownership) = 0;
+  virtual void SSAUpdater_addAvailableValue(SILBasicBlock *block, SILValue value) = 0;
+  virtual SILValue SSAUpdater_getValueAtEndOfBlock(SILBasicBlock *block) = 0;
+  virtual SILValue SSAUpdater_getValueInMiddleOfBlock(SILBasicBlock *block) = 0;
+  ArrayRef<SILPhiArgument*> SSAUpdater_getInsertedPhis() { return insertedPhisBySSAUpdater; }
+};
+
+} // namespace swift
+
+#endif
diff --git a/include/swift/SIL/SILDeclRef.h b/include/swift/SIL/SILDeclRef.h
index d19a66d34659f..6841a7161fd63 100644
--- a/include/swift/SIL/SILDeclRef.h
+++ b/include/swift/SIL/SILDeclRef.h
@@ -38,6 +38,7 @@ namespace swift {
   enum class EffectsKind : uint8_t;
   class AbstractFunctionDecl;
   class AbstractClosureExpr;
+  class ActorIsolation;
   class ValueDecl;
   class FuncDecl;
   class ClosureExpr;
@@ -167,6 +168,10 @@ struct SILDeclRef {
 
     /// The asynchronous main entry-point function.
     AsyncEntryPoint,
+
+    /// An init accessor that calls a propery wrapped field's
+    /// backing storage initializer
+    PropertyWrappedFieldInitAccessor
   };
 
   /// Represents the variants of a back deployable function.
@@ -210,27 +215,27 @@ struct SILDeclRef {
 
   /// Returns the type of AST node location being stored by the SILDeclRef.
   LocKind getLocKind() const {
-    if (loc.is<ValueDecl *>())
+    if (isa<ValueDecl *>(loc))
       return LocKind::Decl;
-    if (loc.is<AbstractClosureExpr *>())
+    if (isa<AbstractClosureExpr *>(loc))
       return LocKind::Closure;
-    if (loc.is<FileUnit *>())
+    if (isa<FileUnit *>(loc))
       return LocKind::File;
     llvm_unreachable("Unhandled location kind!");
   }
 
   /// The derivative function identifier.
   AutoDiffDerivativeFunctionIdentifier * getDerivativeFunctionIdentifier() const {
-    if (!pointer.is<AutoDiffDerivativeFunctionIdentifier *>())
+    if (!isa<AutoDiffDerivativeFunctionIdentifier *>(pointer))
       return nullptr;
-    return pointer.get<AutoDiffDerivativeFunctionIdentifier *>();
+    return cast<AutoDiffDerivativeFunctionIdentifier *>(pointer);
   }
 
   GenericSignature getSpecializedSignature() const {
-    if (!pointer.is<const GenericSignatureImpl *>())
+    if (!isa<const GenericSignatureImpl *>(pointer))
       return GenericSignature();
     else
-      return GenericSignature(pointer.get<const GenericSignatureImpl *>());
+      return GenericSignature(cast<const GenericSignatureImpl *>(pointer));
   }
 
   /// Produces a null SILDeclRef.
@@ -288,8 +293,8 @@ struct SILDeclRef {
   bool isNull() const { return loc.isNull(); }
   explicit operator bool() const { return !isNull(); }
 
-  bool hasDecl() const { return loc.is<ValueDecl *>(); }
-  bool hasFileUnit() const { return loc.is<FileUnit *>(); }
+  bool hasDecl() const { return isa<ValueDecl *>(loc); }
+  bool hasFileUnit() const { return isa<FileUnit *>(loc); }
   bool hasClosureExpr() const;
   bool hasAutoClosureExpr() const;
   bool hasFuncDecl() const;
@@ -302,9 +307,8 @@ struct SILDeclRef {
   AutoClosureExpr *getAutoClosureExpr() const;
   FuncDecl *getFuncDecl() const;
   AbstractFunctionDecl *getAbstractFunctionDecl() const;
-  FileUnit *getFileUnit() const {
-    return loc.get<FileUnit *>();
-  }
+  AccessorDecl *getAccessorDecl() const;
+  FileUnit *getFileUnit() const { return cast<FileUnit *>(loc); }
 
   /// Get ModuleDecl that contains the SILDeclRef
   ModuleDecl *getModuleContext() const;
@@ -385,6 +389,10 @@ struct SILDeclRef {
 
   /// True if the SILDeclRef references an init accessor declaration.
   bool isInitAccessor() const;
+  /// True if the SILDeclRef references an borrow accessor declaration.
+  bool isBorrowAccessor() const;
+  /// True if the SILDeclRef references an mutate accessor declaration.
+  bool isMutateAccessor() const;
 
   /// True if the function should be treated as transparent.
   bool isTransparent() const;
@@ -396,11 +404,25 @@ struct SILDeclRef {
   SerializedKind_t getSerializedKind() const;
   /// True if the function has noinline attribute.
   bool isNoinline() const;
-  /// True if the function has __always inline attribute.
+  /// True if the function has always inline attribute.
   bool isAlwaysInline() const;
+  /// True if the function has __always inline attribute.
+  bool isUnderscoredAlwaysInline() const;
   /// True if the function has the @backDeployed attribute.
   bool isBackDeployed() const;
 
+  /// True if this entity should have a non-unique definition based on the
+  /// embedded linkage model.
+  bool hasNonUniqueDefinition() const;
+
+  /// True if the declaration is explicitly marked as being exposed to a
+  /// foreign language or environment,
+  static bool declExposedToForeignLanguage(const ValueDecl *decl);
+
+  /// True if the declaration should have a non-unique definition based on the
+  /// embedded linkage model.
+  static bool declHasNonUniqueDefinition(const ValueDecl *decl);
+
   /// Return the expected linkage for a definition of this declaration.
   SILLinkage getDefinitionLinkage() const;
 
@@ -433,7 +455,7 @@ struct SILDeclRef {
                       /*knownToBeLocal=*/false,
                       /*runtimeAccessible=*/false, backDeploymentKind,
                       defaultArgIndex, isAsyncLetClosure,
-                      pointer.get<AutoDiffDerivativeFunctionIdentifier *>());
+                      cast<AutoDiffDerivativeFunctionIdentifier *>(pointer));
   }
   /// Returns the distributed entry point corresponding to the same decl.
   SILDeclRef asDistributed(bool distributed = true) const {
@@ -442,7 +464,7 @@ struct SILDeclRef {
                       /*distributed=*/distributed,
                       /*knownToBeLocal=*/false, isRuntimeAccessible,
                       backDeploymentKind, defaultArgIndex, isAsyncLetClosure,
-                      pointer.get<AutoDiffDerivativeFunctionIdentifier *>());
+                      cast<AutoDiffDerivativeFunctionIdentifier *>(pointer));
   }
 
   /// Returns the distributed known-to-be-local entry point corresponding to
@@ -454,7 +476,7 @@ struct SILDeclRef {
                       /*distributedKnownToBeLocal=*/isLocal,
                       isRuntimeAccessible, backDeploymentKind, defaultArgIndex,
                       isAsyncLetClosure,
-                      pointer.get<AutoDiffDerivativeFunctionIdentifier *>());
+                      cast<AutoDiffDerivativeFunctionIdentifier *>(pointer));
   }
 
   /// Returns the runtime accessible entry point corresponding to the same decl.
@@ -469,7 +491,7 @@ struct SILDeclRef {
     return SILDeclRef(loc.getOpaqueValue(), kind, isForeign, distributedThunk,
                       isKnownToBeLocal, isRuntimeAccessible, backDeploymentKind,
                       defaultArgIndex, isAsyncLetClosure,
-                      pointer.get<AutoDiffDerivativeFunctionIdentifier *>());
+                      cast<AutoDiffDerivativeFunctionIdentifier *>(pointer));
   }
 
   /// Returns the entry point for the corresponding autodiff derivative
@@ -485,7 +507,7 @@ struct SILDeclRef {
   /// Returns the entry point for the original function corresponding to an
   /// autodiff derivative function.
   SILDeclRef asAutoDiffOriginalFunction() const {
-    assert(pointer.get<AutoDiffDerivativeFunctionIdentifier *>());
+    assert(cast<AutoDiffDerivativeFunctionIdentifier *>(pointer));
     SILDeclRef declRef = *this;
     declRef.pointer = (AutoDiffDerivativeFunctionIdentifier *)nullptr;
     return declRef;
@@ -498,6 +520,8 @@ struct SILDeclRef {
     return result;
   }
 
+  ActorIsolation getActorIsolation() const;
+
   /// True if the decl ref references a thunk from a natively foreign
   /// declaration to Swift calling convention.
   bool isForeignToNativeThunk() const;
@@ -594,14 +618,14 @@ struct SILDeclRef {
   bool canBeDynamicReplacement() const;
 
   bool isAutoDiffDerivativeFunction() const {
-    return pointer.is<AutoDiffDerivativeFunctionIdentifier *>() &&
-           pointer.get<AutoDiffDerivativeFunctionIdentifier *>() != nullptr;
+    return isa<AutoDiffDerivativeFunctionIdentifier *>(pointer) &&
+           cast<AutoDiffDerivativeFunctionIdentifier *>(pointer) != nullptr;
   }
 
   AutoDiffDerivativeFunctionIdentifier *
   getAutoDiffDerivativeFunctionIdentifier() const {
     assert(isAutoDiffDerivativeFunction());
-    return pointer.get<AutoDiffDerivativeFunctionIdentifier *>();
+    return cast<AutoDiffDerivativeFunctionIdentifier *>(pointer);
   }
   
   bool hasAsync() const;
diff --git a/include/swift/SIL/SILFunction.h b/include/swift/SIL/SILFunction.h
index e93779f9e52da..aeaeb6c8d7bd8 100644
--- a/include/swift/SIL/SILFunction.h
+++ b/include/swift/SIL/SILFunction.h
@@ -42,6 +42,7 @@ class BasicBlockBitfield;
 class NodeBitfield;
 class OperandBitfield;
 class CalleeCache;
+class SILTypeProperties;
 class SILUndef;
 
 namespace Lowering {
@@ -51,7 +52,7 @@ class AbstractionPattern;
 
 enum IsBare_t { IsNotBare, IsBare };
 enum IsTransparent_t { IsNotTransparent, IsTransparent };
-enum Inline_t { InlineDefault, NoInline, AlwaysInline };
+enum Inline_t { InlineDefault, NoInline, HeuristicAlwaysInline, AlwaysInline };
 enum IsThunk_t {
   IsNotThunk,
   IsThunk,
@@ -92,7 +93,8 @@ enum class PerformanceConstraints : uint8_t {
   NoLocks = 2,
   NoRuntime = 3,
   NoExistentials = 4,
-  NoObjCBridging = 5
+  NoObjCBridging = 5,
+  ManualOwnership = 6,
 };
 
 class SILSpecializeAttr final {
@@ -235,6 +237,8 @@ class SILFunction
   /// The lowered type of the function.
   CanSILFunctionType LoweredType;
 
+  CanSILFunctionType LoweredTypeInContext;
+
   /// The context archetypes of the function.
   GenericEnvironment *GenericEnv = nullptr;
 
@@ -571,6 +575,9 @@ class SILFunction
   CanSILFunctionType getLoweredFunctionType() const {
     return LoweredType;
   }
+
+  CanSILFunctionType getLoweredFunctionTypeInContext() const;
+
   CanSILFunctionType
   getLoweredFunctionTypeInContext(TypeExpansionContext context) const;
 
@@ -658,6 +665,10 @@ class SILFunction
 
   bool isNoReturnFunction(TypeExpansionContext context) const;
 
+  /// True if this function should have a non-unique definition based on the
+  /// embedded linkage model.
+  bool hasNonUniqueDefinition() const;
+
   /// Unsafely rewrite the lowered type of this function.
   ///
   /// This routine does not touch the entry block arguments
@@ -784,11 +795,18 @@ class SILFunction
     return TypeExpansionContext(*this);
   }
 
+  SILTypeProperties getTypeProperties(Lowering::AbstractionPattern orig,
+                                      Type subst) const;
+  SILTypeProperties getTypeProperties(Type subst) const;
+  SILTypeProperties getTypeProperties(SILType type) const;
+
   const Lowering::TypeLowering &
-  getTypeLowering(Lowering::AbstractionPattern orig, Type subst);
+  getTypeLowering(Lowering::AbstractionPattern orig, Type subst) const;
 
   const Lowering::TypeLowering &getTypeLowering(Type t) const;
 
+  const Lowering::TypeLowering &getTypeLowering(SILType type) const;
+
   SILType getLoweredType(Lowering::AbstractionPattern orig, Type subst) const;
 
   SILType getLoweredType(Type t) const;
@@ -801,8 +819,6 @@ class SILFunction
 
   SILType getLoweredType(SILType t) const;
 
-  const Lowering::TypeLowering &getTypeLowering(SILType type) const;
-
   bool isTypeABIAccessible(SILType type) const;
 
   /// Returns true if this function has a calling convention that has a self
@@ -910,6 +926,14 @@ class SILFunction
     return swift::isAvailableExternally(getLinkage());
   }
 
+  /// Helper method that determines whether this SILFunction is a Swift runtime
+  /// function, such as swift_retain.
+  bool isSwiftRuntimeFunction() const;
+
+  /// Helper method that determines whether a function with the given name and
+  /// parent module is a Swift runtime function such as swift_retain.
+  static bool isSwiftRuntimeFunction(StringRef name, const ModuleDecl *module);
+
   /// Helper method which returns true if the linkage of the SILFunction
   /// indicates that the object's definition might be required outside the
   /// current SILModule.
@@ -1218,6 +1242,8 @@ class SILFunction
   // Used by the MemoryLifetimeVerifier
   bool argumentMayRead(Operand *argOp, SILValue addr);
 
+  bool isDeinitBarrier();
+
   Purpose getSpecialPurpose() const { return specialPurpose; }
 
   /// Get this function's global_init attribute.
@@ -1316,7 +1342,7 @@ class SILFunction
                              SubstitutionMap forwardingSubs) {
     GenericEnv = env;
     CapturedEnvs = capturedEnvs;
-    ForwardingSubMap = forwardingSubs;
+    ForwardingSubMap = forwardingSubs.getCanonical();
   }
 
   /// Retrieve the generic signature from the generic environment of this
@@ -1461,6 +1487,10 @@ class SILFunction
     return actorIsolation;
   }
 
+  bool isNonisolatedNonsending() const {
+    return actorIsolation && actorIsolation->isCallerIsolationInheriting();
+  }
+
   /// Return the source file that this SILFunction belongs to if it exists.
   SourceFile *getSourceFile() const;
 
@@ -1672,7 +1702,8 @@ class SILFunction
   }
 
   /// Verifies the lifetime of memory locations in the function.
-  void verifyMemoryLifetime(CalleeCache *calleeCache);
+  void verifyMemoryLifetime(CalleeCache *calleeCache,
+                            DeadEndBlocks *deadEndBlocks);
 
   /// Verifies ownership of the function.
   /// Since we don't have complete lifetimes everywhere, computes DeadEndBlocks
diff --git a/include/swift/SIL/SILFunctionConventions.h b/include/swift/SIL/SILFunctionConventions.h
index f431f76e5a081..4f5b8cf25c535 100644
--- a/include/swift/SIL/SILFunctionConventions.h
+++ b/include/swift/SIL/SILFunctionConventions.h
@@ -101,6 +101,15 @@ class SILModuleConventions {
   
   SILModule &getModule() const { return *M; }
 
+  /// Is the current convention to represent address-only types in their final,
+  /// lowered form of a raw address?
+  ///
+  /// Otherwise, address-only types are instead represented opaquely as SSA
+  /// values, until the mandatory SIL pass AddressLowering has run.
+  ///
+  /// See the -enable-sil-opaque-values flag.
+  ///
+  /// \returns true iff address-only types are represented as raw addresses
   bool useLoweredAddresses() const { return loweredAddresses; }
 
   bool isTypeIndirectForIndirectParamConvention(CanType paramTy) {
@@ -261,9 +270,20 @@ class SILFunctionConventions {
   }
 
   bool isArgumentIndexOfIndirectErrorResult(unsigned idx) {
-    unsigned indirectResults = getNumIndirectSILResults();
-    return idx >= indirectResults &&
-           idx < indirectResults + getNumIndirectSILErrorResults();
+    if (auto errorIdx = getArgumentIndexOfIndirectErrorResult())
+      return idx == *errorIdx;
+
+    return false;
+  }
+
+  std::optional<unsigned> getArgumentIndexOfIndirectErrorResult() {
+    unsigned hasIndirectErrorResult = getNumIndirectSILErrorResults();
+    if (!hasIndirectErrorResult)
+      return std::nullopt;
+
+    assert(hasIndirectErrorResult == 1);
+    // Error index is the first one after the indirect return results, if any.
+    return getNumIndirectSILResults();
   }
 
   unsigned getNumAutoDiffSemanticResults() const {
@@ -298,6 +318,22 @@ class SILFunctionConventions {
         IndirectSILResultFilter(silConv.loweredAddresses));
   }
 
+  bool hasGuaranteedResult() const {
+    if (funcTy->getNumResults() != 1) {
+      return false;
+    }
+    return funcTy->getResults()[0].getConvention() ==
+           ResultConvention::Guaranteed;
+  }
+
+  bool hasGuaranteedAddressResult() const {
+    if (funcTy->getNumResults() != 1) {
+      return false;
+    }
+    return funcTy->getResults()[0].getConvention() ==
+           ResultConvention::GuaranteedAddress;
+  }
+
   struct SILResultTypeFunc;
 
   // Gratuitous template parameter is to delay instantiating `mapped_iterator`
@@ -637,6 +673,8 @@ inline bool SILModuleConventions::isIndirectSILResult(SILResultInfo result,
   case ResultConvention::Unowned:
   case ResultConvention::UnownedInnerPointer:
   case ResultConvention::Autoreleased:
+  case ResultConvention::GuaranteedAddress:
+  case ResultConvention::Guaranteed:
     return false;
   }
 
@@ -657,10 +695,11 @@ inline SILType SILModuleConventions::getSILYieldInterfaceType(
   return getSILParamInterfaceType(yield, loweredAddresses);
 }
 
-inline SILType SILModuleConventions::getSILResultInterfaceType(
-                                                      SILResultInfo result,
-                                                      bool loweredAddresses) {
-  return SILModuleConventions::isIndirectSILResult(result, loweredAddresses)
+inline SILType
+SILModuleConventions::getSILResultInterfaceType(SILResultInfo result,
+                                                bool loweredAddresses) {
+  return SILModuleConventions::isIndirectSILResult(result, loweredAddresses) ||
+                 result.isGuaranteedAddressResult()
              ? SILType::getPrimitiveAddressType(result.getInterfaceType())
              : SILType::getPrimitiveObjectType(result.getInterfaceType());
 }
diff --git a/include/swift/SIL/SILGlobalVariable.h b/include/swift/SIL/SILGlobalVariable.h
index 2b507d465d722..fef50bee40ea0 100644
--- a/include/swift/SIL/SILGlobalVariable.h
+++ b/include/swift/SIL/SILGlobalVariable.h
@@ -51,7 +51,11 @@ class SILGlobalVariable
 
   /// The SIL module that the global variable belongs to.
   SILModule &Module;
-  
+
+  /// The module that defines this global variable. This member should only be
+  /// when a global variable is deserialized to be emitted into another module.
+  ModuleDecl *ParentModule = nullptr;
+
   /// The mangled name of the variable, which will be propagated to the
   /// binary.  A pointer into the module's lookup table.
   StringRef Name;
@@ -75,6 +79,10 @@ class SILGlobalVariable
   /// once (either in its declaration, or once later), making it immutable.
   unsigned IsLet : 1;
 
+  /// Whether this declaration was marked `@_used`, meaning that it should be
+  /// added to the llvm.used list.
+  unsigned IsUsed : 1;
+
   /// Whether or not this is a declaration.
   unsigned IsDeclaration : 1;
 
@@ -116,6 +124,15 @@ class SILGlobalVariable
 
   SILModule &getModule() const { return Module; }
 
+  /// Returns the module that defines this function.
+  ModuleDecl *getParentModule() const;
+
+  /// Sets \c ParentModule as fallback if \c DeclCtxt is not available to
+  /// provide the parent module.
+  void setParentModule(ModuleDecl *module) {
+    ParentModule = module;
+  }
+
   SILType getLoweredType() const { return LoweredType; }
   CanSILFunctionType getLoweredFunctionType() const {
     return LoweredType.castTo<SILFunctionType>();
@@ -147,6 +164,10 @@ class SILGlobalVariable
   /// might be referenced from outside the current compilation unit.
   bool isPossiblyUsedExternally() const;
 
+  /// True if this variable should have a non-unique definition based on the
+  /// embedded linkage model.
+  bool hasNonUniqueDefinition() const;
+
   /// Returns true if this global variable should be preserved so it can
   /// potentially be inspected by the debugger.
   bool shouldBePreservedForDebugger() const;
@@ -207,10 +228,9 @@ class SILGlobalVariable
   }
 
   /// Returns true if this global variable has `@_used` attribute.
-  bool markedAsUsed() const {
-    auto *V = getDecl();
-    return V && V->getAttrs().hasAttribute<UsedAttr>();
-  }
+  bool markedAsUsed() const { return IsUsed; }
+
+  void setMarkedAsUsed(bool used) { IsUsed = used; }
 
   /// Returns a SectionAttr if this global variable has `@_section` attribute.
   SectionAttr *getSectionAttr() const {
diff --git a/include/swift/SIL/SILInstruction.h b/include/swift/SIL/SILInstruction.h
index 25a811cde9280..40618b7b580c6 100644
--- a/include/swift/SIL/SILInstruction.h
+++ b/include/swift/SIL/SILInstruction.h
@@ -670,6 +670,10 @@ class SILInstruction : public llvm::ilist_node<SILInstruction> {
   using TransformedOperandValueRange =
     OptionalTransformRange<ArrayRef<Operand>, OperandToTransformedValue>;
 
+  /// Functor for Operand::getUser()
+  struct OperandToUser;
+  using OperandUserRange = TransformRange<ArrayRef<Operand *>, OperandToUser>;
+
   static OperandValueRange getOperandValues(ArrayRef<Operand*> operands);
 
   OperandRefValueRange getOperandValues() const;
@@ -1021,6 +1025,12 @@ struct SILInstruction::OperandRefToValue {
   }
 };
 
+struct SILInstruction::OperandToUser {
+  SILInstruction *operator()(const Operand *use) const {
+    return const_cast<Operand *>(use)->getUser();
+  }
+};
+
 struct SILInstruction::FilterOperandToRealOperand {
   const SILInstruction &i;
 
@@ -1283,7 +1293,9 @@ class ForwardingInstruction {
   /// The resulting forwarded value's ownership, returned by getOwnershipKind(),
   /// is not identical to the forwarding ownership. It differs when the result
   /// is trivial type. e.g. an owned or guaranteed value can be cast to a
-  /// trivial type using owned or guaranteed forwarding.
+  /// trivial type using owned or guaranteed forwarding. Similarly, if a trivial
+  /// value is forwarded into an owned non-Copyable struct or enum, forwarding
+  /// ownership is 'none' while value ownerhip is 'owned'.
   ValueOwnershipKind getForwardingOwnershipKind() const {
     return ownershipKind;
   }
@@ -1725,7 +1737,7 @@ class InstructionBaseWithTrailingOperands
 
   // Destruct tail allocated objects.
   ~InstructionBaseWithTrailingOperands() {
-    Operand *Operands = TrailingObjects::template getTrailingObjects<Operand>();
+    Operand *Operands = this->template getTrailingObjectsNonStrict<Operand>();
     auto end = sharedUInt32().InstructionBaseWithTrailingOperands.numOperands;
     for (unsigned i = 0; i < end; ++i) {
       Operands[i].~Operand();
@@ -1738,13 +1750,13 @@ class InstructionBaseWithTrailingOperands
   }
 
   ArrayRef<Operand> getAllOperands() const {
-    return {TrailingObjects::template getTrailingObjects<Operand>(),
-            sharedUInt32().InstructionBaseWithTrailingOperands.numOperands};
+    return this->template getTrailingObjectsNonStrict<Operand>(
+        sharedUInt32().InstructionBaseWithTrailingOperands.numOperands);
   }
 
   MutableArrayRef<Operand> getAllOperands() {
-    return {TrailingObjects::template getTrailingObjects<Operand>(),
-            sharedUInt32().InstructionBaseWithTrailingOperands.numOperands};
+    return this->template getTrailingObjectsNonStrict<Operand>(
+        sharedUInt32().InstructionBaseWithTrailingOperands.numOperands);
   }
 };
 
@@ -2662,7 +2674,7 @@ class ApplyInstBase<Impl, Base, false> : public Base {
       : Base(kind, DebugLoc, baseArgs...), SubstCalleeType(substCalleeType),
         SpecializationInfo(specializationInfo), NumCallArguments(args.size()),
         NumTypeDependentOperands(typeDependentOperands.size()),
-        Substitutions(subs) {
+        Substitutions(subs.getCanonical()) {
     assert(!!subs == !!callee->getType().castTo<SILFunctionType>()
         ->getInvocationGenericSignature());
 
@@ -2827,13 +2839,13 @@ class ApplyInstBase<Impl, Base, false> : public Base {
   ///   - the formal arguments
   ///   - the type-dependency arguments
   MutableArrayRef<Operand> getAllOperands() {
-    return { asImpl().template getTrailingObjects<Operand>(),
-             getNumAllOperands() };
+    return asImpl().template getTrailingObjectsNonStrict<Operand>(
+        getNumAllOperands());
   }
 
   ArrayRef<Operand> getAllOperands() const {
-    return { asImpl().template getTrailingObjects<Operand>(),
-             getNumAllOperands() };
+    return asImpl().template getTrailingObjectsNonStrict<Operand>(
+        getNumAllOperands());
   }
 
   /// Check whether the given operand index is a call-argument index
@@ -3135,6 +3147,14 @@ class ApplyInst final
          SILFunction &parentFunction,
          const GenericSpecializationInformation *specializationInfo,
          std::optional<ApplyIsolationCrossing> isolationCrossing);
+
+public:
+  bool hasGuaranteedResult() const {
+    return getSubstCalleeConv().hasGuaranteedResult();
+  }
+  bool hasGuaranteedAddressResult() const {
+    return getSubstCalleeConv().hasGuaranteedAddressResult();
+  }
 };
 
 /// PartialApplyInst - Represents the creation of a closure object by partial
@@ -4317,7 +4337,7 @@ class IncrementProfilerCounterInst final
 
   /// The PGO function name for the function in which the counter resides.
   StringRef getPGOFuncName() const {
-    return StringRef(getTrailingObjects<char>(), PGOFuncNameLength);
+    return StringRef(getTrailingObjects(), PGOFuncNameLength);
   }
 
   /// The total number of counters within the function.
@@ -4468,7 +4488,8 @@ class IntegerLiteralInst final
   static IntegerLiteralInst *create(IntegerLiteralExpr *E,
                                     SILDebugLocation Loc, SILModule &M);
   static IntegerLiteralInst *create(SILDebugLocation Loc, SILType Ty,
-                                    intmax_t Value, SILModule &M);
+                                    intmax_t Value, bool treatAsSigned,
+                                    SILModule &M);
   static IntegerLiteralInst *create(SILDebugLocation Loc, SILType Ty,
                                     const APInt &Value, SILModule &M);
 
@@ -4539,7 +4560,7 @@ class StringLiteralInst final
 public:
   /// getValue - Return the string data for the literal, in UTF-8.
   StringRef getValue() const {
-    return {getTrailingObjects<char>(), sharedUInt32().StringLiteralInst.length};
+    return {getTrailingObjects(), sharedUInt32().StringLiteralInst.length};
   }
 
   /// getEncoding - Return the desired encoding of the text.
@@ -4872,6 +4893,7 @@ class EndBorrowInst
 };
 
 /// Different kinds of access.
+/// This enum must stay in sync with `BeginAccessInst.AccessKind` in SwiftCompilerSources.
 enum class SILAccessKind : uint8_t {
   /// An access which takes uninitialized memory and initializes it.
   Init,
@@ -4894,6 +4916,7 @@ enum { NumSILAccessKindBits = 2 };
 StringRef getSILAccessKindName(SILAccessKind kind);
 
 /// Different kinds of exclusivity enforcement for accesses.
+/// This enum must stay in sync with `BeginAccessInst.Enforcement` in SwiftCompilerSources.
 enum class SILAccessEnforcement : uint8_t {
   /// The access's enforcement has not yet been determined.
   Unknown,
@@ -5215,52 +5238,7 @@ class AssignInst
   }
 };
 
-/// AssignByWrapperInst - Represents an abstract assignment via a wrapper,
-/// which may either be an initialization or a store sequence.  This is only
-/// valid in Raw SIL.
-class AssignByWrapperInst
-    : public AssignInstBase<SILInstructionKind::AssignByWrapperInst, 4> {
-  friend SILBuilder;
-  USE_SHARED_UINT8;
-
-public:
-  enum Mode {
-    /// The mode is not decided yet (by DefiniteInitialization).
-    Unknown,
-    
-    /// The initializer is called with Src as argument. The result is stored to
-    /// Dest.
-    Initialization,
-    
-    // Like ``Initialization``, except that the destination is "assigned" rather
-    // than "initialized". This means that the existing value in the destination
-    // is destroyed before the new value is stored.
-    Assign,
-    
-    /// The setter is called with Src as argument. The Dest is not used in this
-    /// case.
-    AssignWrappedValue
-  };
-
-private:
-  AssignByWrapperInst(SILDebugLocation DebugLoc,
-                      SILValue Src, SILValue Dest, SILValue Initializer,
-                      SILValue Setter, Mode mode);
-
-public:
-  SILValue getInitializer() { return Operands[2].get(); }
-  SILValue getSetter() { return  Operands[3].get(); }
-
-  Mode getMode() const {
-    return Mode(sharedUInt8().AssignByWrapperInst.mode);
-  }
-
-  void setMode(Mode mode) {
-    sharedUInt8().AssignByWrapperInst.mode = uint8_t(mode);
-  }
-};
-
-/// AssignOrInitInst - Represents an abstract assignment via a init accessor
+/// AssignOrInitInst - Represents an abstract assignment via an init accessor
 /// or a setter, which may either be an initialization or a store sequence.
 /// This is only valid in Raw SIL.
 ///
@@ -5297,16 +5275,23 @@ class AssignOrInitInst
   };
 
 private:
-  AssignOrInitInst(SILDebugLocation DebugLoc, VarDecl *P, SILValue Self,
+  AssignOrInitInst(SILDebugLocation DebugLoc, VarDecl *P, SILValue SelfOrLocal,
                    SILValue Src, SILValue Initializer, SILValue Setter,
                    Mode mode);
 
 public:
   VarDecl *getProperty() const { return Property; }
-  SILValue getSelf() const { return Operands[0].get(); }
   SILValue getSrc() const { return Operands[1].get(); }
   SILValue getInitializer() const { return Operands[2].get(); }
-  SILValue getSetter() { return  Operands[3].get(); }
+  SILValue getSetter() { return Operands[3].get(); }
+
+  // Init accessors currently don't support local contexts.
+  // The `PropertyWrappedFieldInitAccessor` thunk must work for both local
+  // and nominal contexts. For locals, we work around this by storing the
+  // projected local address directly in the original `Self` operand.
+  // Callers of this method conditionally handle its result based on
+  // the current DeclContext
+  SILValue getSelfOrLocalOperand() const { return Operands[0].get(); }
 
   Mode getMode() const {
     return Mode(sharedUInt8().AssignOrInitInst.mode);
@@ -5328,7 +5313,8 @@ class AssignOrInitInst
 
   unsigned getNumInitializedProperties() const;
 
-  ArrayRef<VarDecl *> getInitializedProperties() const;
+  void forEachInitializedProperty(
+      llvm::function_ref<void(VarDecl *)> callback) const;
   ArrayRef<VarDecl *> getAccessedProperties() const;
 
   ArrayRef<Operand> getAllOperands() const { return Operands.asArray(); }
@@ -5336,6 +5322,7 @@ class AssignOrInitInst
 
   StringRef getPropertyName() const;
   AccessorDecl *getReferencedInitAccessor() const;
+  DeclContext *getDeclContextOrNull() const;
 };
 
 /// Indicates that a memory location is uninitialized at this point and needs to
@@ -5633,7 +5620,7 @@ class SpecifyTestInst final
   void setValueForName(StringRef name, SILValue value) { values[name] = value; }
   llvm::StringMap<SILValue> const &getValues() { return values; }
   StringRef getArgumentsSpecification() const {
-    return StringRef(getTrailingObjects<char>(), ArgumentsSpecificationLength);
+    return StringRef(getTrailingObjects(), ArgumentsSpecificationLength);
   }
 
   ArrayRef<Operand> getAllOperands() const { return {}; }
@@ -5970,7 +5957,7 @@ class ThunkInst final
             Kind kind, SubstitutionMap subs)
       : UnaryInstructionWithTypeDependentOperandsBase(
             debugLoc, operand, typeDependentOperands, outputType),
-        kind(kind), substitutions(subs) {}
+        kind(kind), substitutions(subs.getCanonical()) {}
 
   static ThunkInst *create(SILDebugLocation debugLoc, SILValue operand,
                            SILModule &mod, SILFunction *func, Kind kind,
@@ -6409,6 +6396,42 @@ enum class CastingIsolatedConformances: uint8_t {
   Prohibit
 };
 
+/// Options for checked casts that will be passed down to the dynamic casting machinery.
+class CheckedCastInstOptions {
+  enum Flags {
+    ProhibitIsolatedConformancesBit = 0x01
+  };
+  
+  uint8_t storage = 0;
+  
+  
+public:
+  CheckedCastInstOptions() : storage(0) { }
+  explicit CheckedCastInstOptions(uint8_t storage) : storage(storage) { }
+
+  uint8_t getStorage() const { return storage; }
+
+  CastingIsolatedConformances isolatedConformances() const {
+    return storage & ProhibitIsolatedConformancesBit
+      ? CastingIsolatedConformances::Prohibit
+      : CastingIsolatedConformances::Allow;
+  }
+  
+  CheckedCastInstOptions withIsolatedConformances(CastingIsolatedConformances conformances) const {
+    CheckedCastInstOptions result(*this);
+    switch (conformances) {
+    case CastingIsolatedConformances::Allow:
+      result.storage &= ~ProhibitIsolatedConformancesBit;
+      break;
+        
+    case CastingIsolatedConformances::Prohibit:
+      result.storage |= ProhibitIsolatedConformancesBit;
+      break;
+    }
+    return result;
+  }
+};
+
 /// Perform an unconditional checked cast that aborts if the cast fails.
 class UnconditionalCheckedCastInst final
     : public UnaryInstructionWithTypeDependentOperandsBase<
@@ -6416,11 +6439,11 @@ class UnconditionalCheckedCastInst final
           UnconditionalCheckedCastInst,
           OwnershipForwardingSingleValueInstruction> {
   CanType DestFormalTy;
-  CastingIsolatedConformances IsolatedConformances;
+  CheckedCastInstOptions Options;
   friend SILBuilder;
 
   UnconditionalCheckedCastInst(SILDebugLocation DebugLoc,
-                               CastingIsolatedConformances isolatedConformances,
+                               CheckedCastInstOptions Options,
                                SILValue Operand,
                                ArrayRef<SILValue> TypeDependentOperands,
                                SILType DestLoweredTy, CanType DestFormalTy,
@@ -6429,10 +6452,10 @@ class UnconditionalCheckedCastInst final
             DebugLoc, Operand, TypeDependentOperands, DestLoweredTy,
             forwardingOwnershipKind),
         DestFormalTy(DestFormalTy),
-        IsolatedConformances(isolatedConformances) {}
+        Options(Options) {}
 
   static UnconditionalCheckedCastInst *
-  create(SILDebugLocation DebugLoc, CastingIsolatedConformances isolatedConformances,
+  create(SILDebugLocation DebugLoc, CheckedCastInstOptions options,
          SILValue Operand, SILType DestLoweredTy,
          CanType DestFormalTy, SILFunction &F,
          ValueOwnershipKind forwardingOwnershipKind);
@@ -6444,9 +6467,7 @@ class UnconditionalCheckedCastInst final
   CanType getTargetFormalType() const { return DestFormalTy; }
   SILType getTargetLoweredType() const { return getType(); }
 
-  CastingIsolatedConformances getIsolatedConformances() const {
-    return IsolatedConformances;
-  }
+  CheckedCastInstOptions getCheckedCastOptions() const { return Options; }
 };
 
 /// StructInst - Represents a constructed loadable struct.
@@ -6791,6 +6812,17 @@ class VectorInst final : public InstructionBaseWithTrailingOperands<
   }
 };
 
+class VectorBaseAddrInst
+    : public UnaryInstructionBase<SILInstructionKind::VectorBaseAddrInst,
+                                  SingleValueInstruction> {
+  friend SILBuilder;
+
+  VectorBaseAddrInst(SILDebugLocation debugLoc, SILValue vector, SILType resultTy)
+      : UnaryInstructionBase(debugLoc, vector, resultTy) {}
+public:
+  SILValue getVector() const { return getOperand(); }
+};
+
 /// TupleInst - Represents a constructed loadable tuple.
 class TupleInst final : public InstructionBaseWithTrailingOperands<
                             SILInstructionKind::TupleInst, TupleInst,
@@ -6954,8 +6986,9 @@ class EnumInst
   EnumInst(SILDebugLocation DebugLoc, SILValue Operand,
            EnumElementDecl *Element, SILType ResultTy,
            ValueOwnershipKind forwardingOwnershipKind)
-      : InstructionBase(DebugLoc, ResultTy, forwardingOwnershipKind),
-        Element(Element) {
+    : InstructionBase(DebugLoc, ResultTy,
+                      forwardingOwnershipKind.forwardToInit(ResultTy)),
+      Element(Element) {
     sharedUInt32().EnumInst.caseIndex = InvalidCaseIndex;
 
     if (Operand) {
@@ -7821,6 +7854,7 @@ class OpenExistentialAddrInst
   }
 
   OpenedExistentialAccess getAccessKind() const { return ForAccess; }
+  void setAccessKind(OpenedExistentialAccess kind) { ForAccess = kind; }
 
   CanExistentialArchetypeType getDefinedOpenedArchetype() const {
     const auto archetype = getOpenedArchetypeOf(getType().getASTType());
@@ -8077,20 +8111,6 @@ class InitExistentialMetatypeInst final
          SILFunction *parent);
 
 public:
-  /// Return the object type which was erased.  That is, if this
-  /// instruction erases Decoder<T>.Type.Type to Printable.Type.Type,
-  /// this method returns Decoder<T>.
-  CanType getFormalErasedObjectType() const {
-    auto exType = getType().getASTType();
-    auto concreteType = getOperand()->getType().getASTType();
-    while (auto exMetatype = dyn_cast<ExistentialMetatypeType>(exType)) {
-      exType = exMetatype->getExistentialInstanceType()->getCanonicalType();
-      concreteType = cast<MetatypeType>(concreteType).getInstanceType();
-    }
-    assert(exType.isExistentialType());
-    return concreteType;
-  }
-
   ArrayRef<ProtocolConformanceRef> getConformances() const;
 };
 
@@ -8604,7 +8624,7 @@ class InitBlockStorageHeaderInst
                              SILValue InvokeFunction, SILType BlockType,
                              SubstitutionMap Subs)
       : InstructionBase(DebugLoc, BlockType),
-        Substitutions(Subs),
+        Substitutions(Subs.getCanonical()),
         Operands(this, BlockStorage, InvokeFunction) {
   }
   
@@ -8902,10 +8922,10 @@ class MarkDependenceAddrInst
 
 /// Shared API for MarkDependenceInst and MarkDependenceAddrInst.
 class MarkDependenceInstruction {
-  const SILInstruction *inst = nullptr;
+  SILInstruction *inst = nullptr;
 
 public:
-  explicit MarkDependenceInstruction(const SILInstruction *inst) {
+  explicit MarkDependenceInstruction(SILInstruction *inst) {
     switch (inst->getKind()) {
     case SILInstructionKind::MarkDependenceInst:
     case SILInstructionKind::MarkDependenceAddrInst:
@@ -8966,6 +8986,11 @@ class MarkDependenceInstruction {
     }
     return false;
   }
+
+  SILInstruction *operator->() { return inst; }
+  SILInstruction *operator->() const { return inst; }
+  SILInstruction *operator*() { return inst; }
+  SILInstruction *operator*() const { return inst; }
 };
 
 /// Promote an Objective-C block that is on the stack to the heap, or simply
@@ -9233,6 +9258,7 @@ class MarkUnresolvedNonCopyableValueInst
   friend class SILBuilder;
 
 public:
+  // The raw values must match Instruction.MarkUnresolvedNonCopyableValueInst.CheckKind
   enum class CheckKind : unsigned {
     Invalid = 0,
 
@@ -9593,6 +9619,14 @@ class EndCOWMutationInst
     sharedUInt8().EndCOWMutationInst.keepUnique = keepUnique;
   }
 };
+class EndCOWMutationAddrInst
+    : public UnaryInstructionBase<SILInstructionKind::EndCOWMutationAddrInst,
+                                  NonValueInstruction> {
+  friend SILBuilder;
+
+  EndCOWMutationAddrInst(SILDebugLocation debugLoc, SILValue address)
+      : UnaryInstructionBase(debugLoc, address) {}
+};
 
 /// Given an escaping closure return true iff it has a non-nil context and the
 /// context has a strong reference count greater than 1.
@@ -9850,9 +9884,7 @@ class CondFailInst final
                               StringRef Message, SILModule &M);
 
 public:
-  StringRef getMessage() const {
-    return {getTrailingObjects<char>(), MessageSize};
-  }
+  StringRef getMessage() const { return {getTrailingObjects(), MessageSize}; }
 };
 
 //===----------------------------------------------------------------------===//
@@ -11124,10 +11156,10 @@ class CheckedCastBranchInst final
   SILType DestLoweredTy;
   CanType DestFormalTy;
   bool IsExact;
-  CastingIsolatedConformances IsolatedConformances;
+  CheckedCastInstOptions Options;
 
   CheckedCastBranchInst(SILDebugLocation DebugLoc, bool IsExact,
-                        CastingIsolatedConformances isolatedConformances,
+                        CheckedCastInstOptions Options,
                         SILValue Operand, CanType SrcFormalTy,
                         ArrayRef<SILValue> TypeDependentOperands,
                         SILType DestLoweredTy, CanType DestFormalTy,
@@ -11142,11 +11174,11 @@ class CheckedCastBranchInst final
             preservesOwnership),
         SrcFormalTy(SrcFormalTy), DestLoweredTy(DestLoweredTy),
         DestFormalTy(DestFormalTy), IsExact(IsExact),
-        IsolatedConformances(isolatedConformances) {}
+        Options(Options) {}
 
   static CheckedCastBranchInst *
   create(SILDebugLocation DebugLoc, bool IsExact,
-         CastingIsolatedConformances isolatedConformances, SILValue Operand,
+         CheckedCastInstOptions Options, SILValue Operand,
          CanType SrcFormalTy, SILType DestLoweredTy, CanType DestFormalTy,
          SILBasicBlock *SuccessBB, SILBasicBlock *FailureBB, SILFunction &F,
          ProfileCounter Target1Count, ProfileCounter Target2Count,
@@ -11155,8 +11187,8 @@ class CheckedCastBranchInst final
 public:
   bool isExact() const { return IsExact; }
 
-  CastingIsolatedConformances getIsolatedConformances() const {
-    return IsolatedConformances;
+  CheckedCastInstOptions getCheckedCastOptions() const {
+    return Options;
   }
 
   SILType getSourceLoweredType() const { return getOperand()->getType(); }
@@ -11177,10 +11209,10 @@ class CheckedCastAddrBranchInst final
               SILInstructionKind::CheckedCastAddrBranchInst,
               CheckedCastAddrBranchInst, CastBranchWithConsumptionKindBase> {
   friend SILBuilder;
-  CastingIsolatedConformances IsolatedConformances;
+  CheckedCastInstOptions Options;
 
   CheckedCastAddrBranchInst(SILDebugLocation DebugLoc,
-                            CastingIsolatedConformances isolatedConformances,
+                            CheckedCastInstOptions Options,
                             CastConsumptionKind consumptionKind, SILValue src,
                             CanType srcType, SILValue dest, CanType targetType,
                             ArrayRef<SILValue> TypeDependentOperands,
@@ -11190,7 +11222,7 @@ class CheckedCastAddrBranchInst final
 
   static CheckedCastAddrBranchInst *
   create(SILDebugLocation DebugLoc,
-         CastingIsolatedConformances isolatedConformances,
+         CheckedCastInstOptions options,
          CastConsumptionKind consumptionKind,
          SILValue src, CanType srcType, SILValue dest, CanType targetType,
          SILBasicBlock *successBB, SILBasicBlock *failureBB,
@@ -11198,9 +11230,7 @@ class CheckedCastAddrBranchInst final
          SILFunction &F);
 
 public:
-  CastingIsolatedConformances getIsolatedConformances() const {
-    return IsolatedConformances;
-  }
+  CheckedCastInstOptions getCheckedCastOptions() const { return Options; }
 };
 
 /// Converts a heap object reference to a different type without any runtime
@@ -11243,24 +11273,22 @@ class UnconditionalCheckedCastAddrInst final
                SILInstructionKind::UnconditionalCheckedCastAddrInst,
                UnconditionalCheckedCastAddrInst, NonValueInstruction> {
   friend SILBuilder;
-  CastingIsolatedConformances IsolatedConformances;
+  CheckedCastInstOptions Options;
 
   UnconditionalCheckedCastAddrInst(SILDebugLocation Loc,
-                                   CastingIsolatedConformances isolatedConformances,
+                                   CheckedCastInstOptions options,
                                    SILValue src, CanType sourceType,
                                    SILValue dest, CanType targetType,
                                    ArrayRef<SILValue> TypeDependentOperands);
 
   static UnconditionalCheckedCastAddrInst *
-  create(SILDebugLocation DebugLoc, CastingIsolatedConformances isolatedConformances,
+  create(SILDebugLocation DebugLoc, CheckedCastInstOptions options,
          SILValue src, CanType sourceType,
          SILValue dest, CanType targetType,
          SILFunction &F);
 
 public:
-  CastingIsolatedConformances getIsolatedConformances() const {
-    return IsolatedConformances;
-  }
+  CheckedCastInstOptions getCheckedCastOptions() const { return Options; }
 };
 
 /// A private abstract class to store the destinations of a TryApplyInst.
diff --git a/include/swift/SIL/SILInstructionWorklist.h b/include/swift/SIL/SILInstructionWorklist.h
index f25d62f88b319..eda2dd2fb4eb3 100644
--- a/include/swift/SIL/SILInstructionWorklist.h
+++ b/include/swift/SIL/SILInstructionWorklist.h
@@ -302,9 +302,12 @@ class SILInstructionWorklist : SILInstructionWorklistBase {
   // method to delete the given instruction.
   void eraseInstFromFunction(SILInstruction &instruction,
                              SILBasicBlock::iterator &iterator,
-                             bool addOperandsToWorklist = true) {
-    // Try to salvage debug info first.
-    swift::salvageDebugInfo(&instruction);
+                             bool addOperandsToWorklist = true,
+                             bool salvageDebugInfo = true) {
+    if (salvageDebugInfo) {
+      // Try to salvage debug info first.
+      swift::salvageDebugInfo(&instruction);
+    }
     // Then delete old debug users.
     for (auto result : instruction.getResults()) {
       while (!result->use_empty()) {
@@ -323,9 +326,11 @@ class SILInstructionWorklist : SILInstructionWorklistBase {
   }
 
   void eraseInstFromFunction(SILInstruction &instruction,
-                             bool addOperandsToWorklist = true) {
+                             bool addOperandsToWorklist = true,
+                             bool salvageDebugInfo = true) {
     SILBasicBlock::iterator nullIter;
-    return eraseInstFromFunction(instruction, nullIter, addOperandsToWorklist);
+    return eraseInstFromFunction(instruction, nullIter, addOperandsToWorklist,
+                                 salvageDebugInfo);
   }
 
   void eraseSingleInstFromFunction(SILInstruction &instruction,
diff --git a/include/swift/SIL/SILLocation.h b/include/swift/SIL/SILLocation.h
index 0ec29f4302d4d..a3a5a1eeb6436 100644
--- a/include/swift/SIL/SILLocation.h
+++ b/include/swift/SIL/SILLocation.h
@@ -13,11 +13,12 @@
 #ifndef SWIFT_SIL_LOCATION_H
 #define SWIFT_SIL_LOCATION_H
 
-#include "llvm/ADT/PointerUnion.h"
 #include "swift/AST/ASTNode.h"
+#include "swift/AST/TypeAlignments.h"
 #include "swift/Basic/SourceLoc.h"
+#include "swift/Basic/SwiftBridging.h"
 #include "swift/SIL/SILAllocated.h"
-#include "swift/AST/TypeAlignments.h"
+#include "llvm/ADT/PointerUnion.h"
 
 #include <cstddef>
 #include <type_traits>
@@ -230,14 +231,14 @@ class SILLocation {
   bool isNode(ASTNodeTy Node) const {
     assert(isASTNode());
     ASTNodeTy primaryNd = getPrimaryASTNode();
-    if (primaryNd.getPointer().is<typename base_type<T>::type*>())
-      return isa<T>(Node.getPointer().get<typename base_type<T>::type*>());
+    if (isa<typename base_type<T>::type *>(primaryNd.getPointer()))
+      return isa<T>(cast<typename base_type<T>::type *>(Node.getPointer()));
     return false;
   }
 
   template <typename T>
   T *castNodeTo(ASTNodeTy Node) const {
-    return cast<T>(Node.getPointer().get<typename base_type<T>::type*>());
+    return cast<T>(cast<typename base_type<T>::type *>(Node.getPointer()));
   }
 
   SourceLoc getSourceLoc(ASTNodeTy N) const;
@@ -775,6 +776,11 @@ class SILDebugLocation {
     return autoGenLoc;
   }
 
+  SILDebugLocation getCleanupLocation() const {
+    SILDebugLocation cleanupLoc(CleanupLocation(location), getScope());
+    return cleanupLoc;
+  }
+
   bool isEqualTo(SILDebugLocation rhs) const {
     return getLocation() == rhs.getLocation() && getScope() == rhs.getScope();
   }
diff --git a/include/swift/SIL/SILModule.h b/include/swift/SIL/SILModule.h
index 6cfb8a451986b..223df90ff99a7 100644
--- a/include/swift/SIL/SILModule.h
+++ b/include/swift/SIL/SILModule.h
@@ -255,9 +255,14 @@ class SILModule {
       VTableEntryCache;
 
   /// Lookup table for SIL witness tables from conformances.
-  llvm::DenseMap<const ProtocolConformance *, SILWitnessTable *>
+  llvm::DenseMap<const RootProtocolConformance *, SILWitnessTable *>
   WitnessTableMap;
 
+  /// Lookup table for specialized witness tables from conformances.
+  /// Currently only used in embedded mode.
+  llvm::DenseMap<const ProtocolConformance *, SILWitnessTable *>
+  specializedWitnessTableMap;
+
   /// The list of SILWitnessTables in the module.
   WitnessTableListType witnessTables;
 
@@ -388,10 +393,6 @@ class SILModule {
 
   bool parsedAsSerializedSIL;
 
-  /// Set if we have registered a deserialization notification handler for
-  /// lowering ownership in non transparent functions.
-  /// This gets set in NonTransparent OwnershipModelEliminator pass.
-  bool regDeserializationNotificationHandlerForNonTransparentFuncOME;
   /// Set if we have registered a deserialization notification handler for
   /// lowering ownership in transparent functions.
   /// This gets set in OwnershipModelEliminator pass.
@@ -444,15 +445,9 @@ class SILModule {
     deserializationNotificationHandlers.erase(handler);
   }
 
-  bool hasRegisteredDeserializationNotificationHandlerForNonTransparentFuncOME() {
-    return regDeserializationNotificationHandlerForNonTransparentFuncOME;
-  }
   bool hasRegisteredDeserializationNotificationHandlerForAllFuncOME() {
     return regDeserializationNotificationHandlerForAllFuncOME;
   }
-  void setRegisteredDeserializationNotificationHandlerForNonTransparentFuncOME() {
-    regDeserializationNotificationHandlerForNonTransparentFuncOME = true;
-  }
   void setRegisteredDeserializationNotificationHandlerForAllFuncOME() {
     regDeserializationNotificationHandlerForAllFuncOME = true;
   }
@@ -862,20 +857,26 @@ class SILModule {
   /// Returns true if linking succeeded, false otherwise.
   bool linkFunction(SILFunction *F, LinkingMode LinkMode);
 
+  /// Attempt to deserialize witness table for protocol conformance \p PC.
+  ///
+  /// Returns true if linking succeeded, false otherwise.
+  bool linkWitnessTable(ProtocolConformance *PC, LinkingMode LinkMode);
+
   /// Check if a given function exists in any of the modules.
   /// i.e. it can be linked by linkFunction.
   bool hasFunction(StringRef Name);
 
-  /// Look up the SILWitnessTable representing the lowering of a protocol
-  /// conformance, and collect the substitutions to apply to the referenced
-  /// witnesses, if any.
-  ///
-  /// \arg C The protocol conformance mapped key to use to lookup the witness
-  ///        table.
-  /// \arg deserializeLazily If we cannot find the witness table should we
-  ///                        attempt to lazily deserialize it.
+  /// Look up the SILWitnessTable representing the lowering of a conformance `C`.
+  /// If a specialized witness table exists for the conformance, return the specialized table.
+  /// Specialized witness tables are currently only used in embedded mode.
   SILWitnessTable *lookUpWitnessTable(const ProtocolConformance *C);
 
+  /// Look up the SILWitnessTable representing the lowering of a conformance `C`.
+  /// The `isSpecialized` flag specifies if only non-specialized or specialized witness
+  /// tables are looked up.
+  /// Specialized witness tables are currently only used in embedded mode.
+  SILWitnessTable *lookUpWitnessTable(const ProtocolConformance *C, bool isSpecialized);
+
   /// Attempt to lookup \p Member in the witness table for \p C.
   ///
   /// Also, deserialize all referenced functions according to the \p linkgingMode.
diff --git a/include/swift/SIL/SILNode.h b/include/swift/SIL/SILNode.h
index 091c4b5441775..39a358c631a58 100644
--- a/include/swift/SIL/SILNode.h
+++ b/include/swift/SIL/SILNode.h
@@ -120,7 +120,6 @@ class alignas(8) SILNode :
   enum { NumStoreOwnershipQualifierBits = 2 };
   enum { NumLoadOwnershipQualifierBits = 2 };
   enum { NumAssignOwnershipQualifierBits = 2 };
-  enum { NumAssignByWrapperModeBits = 2 };
   enum { NumSILAccessKindBits = 2 };
   enum { NumSILAccessEnforcementBits = 3 };
   enum { NumAllocRefTailTypesBits = 4 };
@@ -196,7 +195,6 @@ class alignas(8) SILNode :
     SHARED_FIELD(StoreInst, uint8_t ownershipQualifier);
     SHARED_FIELD(LoadInst, uint8_t ownershipQualifier);
     SHARED_FIELD(AssignInst, uint8_t ownershipQualifier);
-    SHARED_FIELD(AssignByWrapperInst, uint8_t mode);
     SHARED_FIELD(AssignOrInitInst, uint8_t mode);
     SHARED_FIELD(StringLiteralInst, uint8_t encoding);
     SHARED_FIELD(SwitchValueInst, bool hasDefault);
diff --git a/include/swift/SIL/SILNodes.def b/include/swift/SIL/SILNodes.def
index 06b3f22ece711..ec872de025599 100644
--- a/include/swift/SIL/SILNodes.def
+++ b/include/swift/SIL/SILNodes.def
@@ -528,7 +528,6 @@ ABSTRACT_VALUE_AND_INST(SingleValueInstruction, ValueBase, SILInstruction)
 
   SINGLE_VALUE_INST(EndCOWMutationInst, end_cow_mutation,
                             SingleValueInstruction, None, DoesNotRelease)
-
   SINGLE_VALUE_INST(DestroyNotEscapedClosureInst, destroy_not_escaped_closure,
                     SingleValueInstruction, MayHaveSideEffects, MayRelease)
 
@@ -588,6 +587,8 @@ ABSTRACT_VALUE_AND_INST(SingleValueInstruction, ValueBase, SILInstruction)
                     SingleValueInstruction, None, DoesNotRelease)
   SINGLE_VALUE_INST(VectorInst, vector,
                     SingleValueInstruction, None, DoesNotRelease)
+  SINGLE_VALUE_INST(VectorBaseAddrInst, vector_base_addr,
+                    SingleValueInstruction, None, DoesNotRelease)
   SINGLE_VALUE_INST(TupleInst, tuple,
                     SingleValueInstruction, None, DoesNotRelease)
   SINGLE_VALUE_INST(TupleExtractInst, tuple_extract,
@@ -836,8 +837,6 @@ NON_VALUE_INST(StoreInst, store,
                SILInstruction, MayHaveSideEffects, MayRelease)
 NON_VALUE_INST(AssignInst, assign,
                SILInstruction, MayWrite, DoesNotRelease)
-NON_VALUE_INST(AssignByWrapperInst, assign_by_wrapper,
-               SILInstruction, MayWrite, DoesNotRelease)
 NON_VALUE_INST(AssignOrInitInst, assign_or_init,
                SILInstruction, MayWrite, DoesNotRelease)
 NON_VALUE_INST(MarkFunctionEscapeInst, mark_function_escape,
@@ -906,9 +905,11 @@ NON_VALUE_INST(IncrementProfilerCounterInst, increment_profiler_counter,
 // MarkDependenceAddrInst has read effects for the base operand. See
 // getMemoryBehavior().
 NON_VALUE_INST(MarkDependenceAddrInst, mark_dependence_addr,
-               SILInstruction, None, DoesNotRelease)
+               SILInstruction, MayReadWrite, DoesNotRelease)
 
-NODE_RANGE(NonValueInstruction, UnreachableInst, MarkDependenceAddrInst)
+NON_VALUE_INST(EndCOWMutationAddrInst, end_cow_mutation_addr,
+               SILInstruction, MayHaveSideEffects, DoesNotRelease)
+NODE_RANGE(NonValueInstruction, UnreachableInst, EndCOWMutationAddrInst)
 
 ABSTRACT_INST(MultipleValueInstruction, SILInstruction)
 MULTIPLE_VALUE_INST(BeginApplyInst, begin_apply,
diff --git a/include/swift/SIL/SILRemarkStreamer.h b/include/swift/SIL/SILRemarkStreamer.h
index 9bb8cc182af1a..503558e336dde 100644
--- a/include/swift/SIL/SILRemarkStreamer.h
+++ b/include/swift/SIL/SILRemarkStreamer.h
@@ -72,6 +72,10 @@ class SILRemarkStreamer {
   /// \c llvm::remarks::RemarkStreamer with the given \c LLVMContext.
   void intoLLVMContext(llvm::LLVMContext &Ctx) &;
 
+  std::unique_ptr<llvm::raw_fd_ostream> releaseStream() {
+    return std::move(remarkStream);
+  }
+
 public:
   /// Emit a remark through the streamer.
   template <typename RemarkT>
@@ -107,7 +111,7 @@ llvm::remarks::Remark SILRemarkStreamer::toLLVMRemark(
   llvmRemark.RemarkType = toRemarkType<RemarkT>();
   llvmRemark.PassName = optRemark.getPassName();
   llvmRemark.RemarkName = optRemark.getIdentifier();
-  llvmRemark.FunctionName = optRemark.getDemangledFunctionName();
+  llvmRemark.FunctionName = optRemark.getFunction()->getName();
   llvmRemark.Loc =
       toRemarkLocation(optRemark.getLocation(), getASTContext().SourceMgr);
 
diff --git a/include/swift/SIL/SILType.h b/include/swift/SIL/SILType.h
index aa3956cb3185e..de96a05269914 100644
--- a/include/swift/SIL/SILType.h
+++ b/include/swift/SIL/SILType.h
@@ -20,6 +20,7 @@
 
 #include "swift/AST/SILLayout.h"
 #include "swift/AST/Types.h"
+#include "swift/Basic/Assertions.h"
 #include "swift/SIL/AbstractionPattern.h"
 #include "swift/SIL/Lifetime.h"
 #include "llvm/ADT/Hashing.h"
@@ -109,7 +110,7 @@ class SILType {
   SILType(CanType ty, SILValueCategory category)
       : value(ty.getPointer(), unsigned(category)) {
     if (!ty) return;
-    assert(ty->isLegalSILType() &&
+    ASSERT(ty->isLegalSILType() &&
            "constructing SILType with type that should have been "
            "eliminated by SIL lowering");
   }
@@ -419,6 +420,9 @@ class SILType {
   
   /// Returns true if the referenced type is guaranteed to have a
   /// single-retainable-pointer representation.
+  /// This does not include C++ imported `SWIFT_SHARED_REFERENCE` classes.
+  /// They act as Swift classes but are not compatible with Swift's
+  /// retain/release runtime functions.
   bool hasRetainablePointerRepresentation() const {
     return getASTType()->hasRetainablePointerRepresentation();
   }
@@ -754,6 +758,13 @@ class SILType {
   SILType subst(SILModule &M, SubstitutionMap subs,
                 TypeExpansionContext context) const;
 
+  /// Strip concurrency annotations from the representation type.
+  SILType stripConcurrency(bool recursive, bool dropGlobalActor) {
+    auto strippedASTTy = getASTType()->stripConcurrency(recursive, dropGlobalActor);
+    return SILType::getPrimitiveType(strippedASTTy->getCanonicalType(),
+                                     getCategory());
+  }
+
   /// Return true if this type references a "ref" type that has a single pointer
   /// representation. Class existentials do not always qualify.
   bool isHeapObjectReferenceType() const;
diff --git a/include/swift/SIL/SILTypeProperties.h b/include/swift/SIL/SILTypeProperties.h
new file mode 100644
index 0000000000000..273b072b3c276
--- /dev/null
+++ b/include/swift/SIL/SILTypeProperties.h
@@ -0,0 +1,269 @@
+//===--- SILTypeProperties.h - Properties of SIL types ----------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SIL_SILTYPEPROPERTIES_H
+#define SWIFT_SIL_SILTYPEPROPERTIES_H
+
+namespace swift {
+
+/// Is a lowered SIL type trivial?  That is, are copies ultimately just
+/// bit-copies, and it takes no work to destroy a value?
+enum IsTrivial_t : bool {
+  IsNotTrivial = false,
+  IsTrivial = true
+};
+
+/// Is a lowered SIL type the Builtin.RawPointer or a struct/tuple/enum which
+/// contains a Builtin.RawPointer?
+/// HasRawPointer is true only for types that are known to contain
+/// Builtin.RawPointer. It is not assumed true for generic or resilient types.
+enum HasRawPointer_t : bool {
+  DoesNotHaveRawPointer = false,
+  HasRawPointer = true
+};
+
+/// Is a lowered SIL type fixed-ABI?  That is, can the current context
+/// assign it a fixed size and alignment and perform value operations on it
+/// (such as copies, destroys, constructions, and projections) without
+/// metadata?
+///
+/// Note that a fully concrete type can be non-fixed-ABI without being
+/// itself resilient if it contains a subobject which is not fixed-ABI.
+///
+/// Also note that we're only concerned with the external value ABI here:
+/// resilient class types are still fixed-ABI, indirect enum cases do not
+/// affect the fixed-ABI-ness of the enum, and so on.
+enum IsFixedABI_t : bool {
+  IsNotFixedABI = false,
+  IsFixedABI = true
+};
+
+/// Is a lowered SIL type address-only?  That is, is the current context
+/// required to keep the value in memory for some reason?
+///
+/// A type might be address-only because:
+///
+///   - it is not fixed-size (e.g. because it is a resilient type) and
+///     therefore cannot be loaded into a statically-boundable set of
+///     registers; or
+///
+///   - it is semantically bound to memory, either because its storage
+///     address is used by the language runtime to implement its semantics
+///     (as with a weak reference) or because its representation is somehow
+///     address-dependent (as with something like a relative pointer).
+///
+/// An address-only type can be fixed-layout and/or trivial.
+/// A non-fixed-layout type is always address-only.
+enum IsAddressOnly_t : bool {
+  IsNotAddressOnly = false,
+  IsAddressOnly = true
+};
+
+/// Is this type somewhat like a reference-counted type?
+enum IsReferenceCounted_t : bool {
+  IsNotReferenceCounted = false,
+  IsReferenceCounted = true
+};
+
+/// Is this type address only because it's resilient?
+enum IsResilient_t : bool {
+  IsNotResilient = false,
+  IsResilient = true
+};
+
+/// Does this type contain an opaque result type that affects type lowering?
+enum IsTypeExpansionSensitive_t : bool {
+  IsNotTypeExpansionSensitive = false,
+  IsTypeExpansionSensitive = true
+};
+
+/// Is the type infinitely defined in terms of itself? (Such types can never
+/// be concretely instantiated, but may still arise from generic specialization.)
+enum IsInfiniteType_t : bool {
+  IsNotInfiniteType = false,
+  IsInfiniteType = true,
+};
+
+/// Does this type contain any pack-like thing.
+enum HasPack_t : bool {
+  HasNoPack = false,
+  HasPack = true,
+};
+
+/// Is the type addressable-for-dependencies?
+///
+/// Values of an addressable-for-dependency type are passed indirectly into
+/// functions that specify a return value lifetime dependency on the value.
+/// This allows the dependent value to safely contain pointers to the in-memory
+/// representation of the source of the dependency.
+enum IsAddressableForDependencies_t : bool {
+  IsNotAddressableForDependencies = false,
+  IsAddressableForDependencies = true,
+};
+
+/// Is a lowered SIL type a struct with `@_rawLayout` or contains such a struct?
+enum HasRawLayout_t : bool {
+  DoesNotHaveRawLayout = false,
+  HasRawLayout = true
+};
+
+class SILTypeProperties {
+  // These are chosen so that bitwise-or merges the flags properly.
+  //
+  // clang-format off
+  enum : unsigned {
+    NonTrivialFlag                 = 1 << 0,
+    NonFixedABIFlag                = 1 << 1,
+    AddressOnlyFlag                = 1 << 2,
+    ResilientFlag                  = 1 << 3,
+    TypeExpansionSensitiveFlag     = 1 << 4,
+    InfiniteFlag                   = 1 << 5,
+    HasRawPointerFlag              = 1 << 6,
+    LexicalFlag                    = 1 << 7,
+    HasPackFlag                    = 1 << 8,
+    AddressableForDependenciesFlag = 1 << 9,
+    HasRawLayoutFlag               = 1 << 10,
+  };
+  // clang-format on
+
+  uint16_t Flags;
+
+public:
+  /// Construct a default SILTypeProperties, which corresponds to
+  /// a trivial, loadable, fixed-layout type.
+  constexpr SILTypeProperties() : Flags(0) {}
+
+  constexpr SILTypeProperties(
+      IsTrivial_t isTrivial, IsFixedABI_t isFixedABI,
+      IsAddressOnly_t isAddressOnly, IsResilient_t isResilient,
+      IsTypeExpansionSensitive_t isTypeExpansionSensitive =
+          IsNotTypeExpansionSensitive,
+      HasRawPointer_t hasRawPointer = DoesNotHaveRawPointer,
+      IsLexical_t isLexical = IsNotLexical, HasPack_t hasPack = HasNoPack,
+      IsAddressableForDependencies_t isAFD = IsNotAddressableForDependencies,
+      HasRawLayout_t hasRawLayout = DoesNotHaveRawLayout)
+      : Flags((isTrivial ? 0U : NonTrivialFlag) |
+              (isFixedABI ? 0U : NonFixedABIFlag) |
+              (isAddressOnly ? AddressOnlyFlag : 0U) |
+              (isResilient ? ResilientFlag : 0U) |
+              (isTypeExpansionSensitive ? TypeExpansionSensitiveFlag : 0U) |
+              (hasRawPointer ? HasRawPointerFlag : 0U) |
+              (isLexical ? LexicalFlag : 0U) |
+              (hasPack ? HasPackFlag : 0U) |
+              (isAFD ? AddressableForDependenciesFlag : 0U) |
+              (hasRawLayout ? HasRawLayoutFlag : 0U)) {}
+
+  constexpr bool operator==(SILTypeProperties p) const {
+    return Flags == p.Flags;
+  }
+
+  static constexpr SILTypeProperties forTrivial() {
+    return {IsTrivial, IsFixedABI, IsNotAddressOnly, IsNotResilient};
+  }
+
+  static constexpr SILTypeProperties forTrivialOpaque() {
+    return {IsTrivial, IsFixedABI, IsNotAddressOnly, IsNotResilient,
+            IsNotTypeExpansionSensitive, HasRawPointer, IsNotLexical,
+            HasNoPack, IsAddressableForDependencies};
+  }
+
+  static constexpr SILTypeProperties forRawPointer() {
+    return {IsTrivial, IsFixedABI, IsNotAddressOnly, IsNotResilient,
+            IsNotTypeExpansionSensitive, HasRawPointer};
+  }
+
+  static constexpr SILTypeProperties forReference() {
+    return {IsNotTrivial, IsFixedABI, IsNotAddressOnly, IsNotResilient,
+            IsNotTypeExpansionSensitive, DoesNotHaveRawPointer, IsLexical};
+  }
+
+  static constexpr SILTypeProperties forOpaque() {
+    return {IsNotTrivial, IsNotFixedABI, IsAddressOnly, IsNotResilient,
+            IsNotTypeExpansionSensitive, HasRawPointer, IsLexical,
+            HasNoPack, IsAddressableForDependencies, HasRawLayout};
+  }
+
+  static constexpr SILTypeProperties forResilient() {
+    return {IsTrivial, IsFixedABI, IsNotAddressOnly, IsResilient,
+            IsNotTypeExpansionSensitive, HasRawPointer, IsNotLexical,
+            HasNoPack, IsNotAddressableForDependencies};
+  }
+
+  void addSubobject(SILTypeProperties other) {
+    Flags |= other.Flags;
+  }
+
+  IsTrivial_t isTrivial() const {
+    return IsTrivial_t((Flags & NonTrivialFlag) == 0);
+  }
+  HasRawPointer_t isOrContainsRawPointer() const {
+    return HasRawPointer_t((Flags & HasRawPointerFlag) != 0);
+  }
+  IsFixedABI_t isFixedABI() const {
+    return IsFixedABI_t((Flags & NonFixedABIFlag) == 0);
+  }
+  IsAddressOnly_t isAddressOnly() const {
+    return IsAddressOnly_t((Flags & AddressOnlyFlag) != 0);
+  }
+  bool isLoadable() const {
+    return !isAddressOnly();
+  }
+  IsResilient_t isResilient() const {
+    return IsResilient_t((Flags & ResilientFlag) != 0);
+  }
+  IsTypeExpansionSensitive_t isTypeExpansionSensitive() const {
+    return IsTypeExpansionSensitive_t(
+        (Flags & TypeExpansionSensitiveFlag) != 0);
+  }
+  IsInfiniteType_t isInfinite() const {
+    return IsInfiniteType_t((Flags & InfiniteFlag) != 0);
+  }
+  IsLexical_t isLexical() const {
+    return IsLexical_t((Flags & LexicalFlag) != 0);
+  }
+  HasPack_t isOrContainsPack() const {
+    return HasPack_t((Flags & HasPackFlag) != 0);
+  }
+  IsAddressableForDependencies_t isAddressableForDependencies() const {
+    return IsAddressableForDependencies_t(
+                              (Flags & AddressableForDependenciesFlag) != 0);
+  }
+  HasRawLayout_t isOrContainsRawLayout() const {
+    return HasRawLayout_t((Flags & HasRawLayoutFlag) != 0);
+  }
+
+  void setNonTrivial() { Flags |= NonTrivialFlag; }
+  void setIsOrContainsRawPointer() { Flags |= HasRawPointerFlag; }
+
+  void setNonFixedABI() { Flags |= NonFixedABIFlag; }
+  void setAddressOnly() { Flags |= AddressOnlyFlag; }
+  void setTypeExpansionSensitive(
+      IsTypeExpansionSensitive_t isTypeExpansionSensitive) {
+    Flags = (Flags & ~TypeExpansionSensitiveFlag) |
+            (isTypeExpansionSensitive ? TypeExpansionSensitiveFlag : 0);
+  }
+  void setInfinite() { Flags |= InfiniteFlag; }
+  void setLexical(IsLexical_t isLexical) {
+    Flags = (Flags & ~LexicalFlag) | (isLexical ? LexicalFlag : 0);
+  }
+  void setHasPack() { Flags |= HasPackFlag; }
+  void setAddressableForDependencies() {
+    Flags |= AddressableForDependenciesFlag;
+  }
+  void setHasRawLayout() {
+    Flags |= HasRawLayoutFlag;
+  }
+};
+
+} // end namespace swift
+
+#endif
diff --git a/include/swift/SIL/SILVTable.h b/include/swift/SIL/SILVTable.h
index 0285c87e332c0..21ad8294bbc77 100644
--- a/include/swift/SIL/SILVTable.h
+++ b/include/swift/SIL/SILVTable.h
@@ -173,15 +173,13 @@ class SILVTable final : public SILAllocated<SILVTable>,
   }
 
   /// Return all of the method entries.
-  ArrayRef<Entry> getEntries() const {
-    return {getTrailingObjects<SILVTableEntry>(), NumEntries};
-  }
+  ArrayRef<Entry> getEntries() const { return getTrailingObjects(NumEntries); }
 
   /// Return all of the method entries mutably.
   /// If you do modify entries, make sure to invoke `updateVTableCache` to update the
   /// SILModule's cache entry.
   MutableArrayRef<Entry> getMutableEntries() {
-    return {getTrailingObjects<SILVTableEntry>(), NumEntries};
+    return getTrailingObjects(NumEntries);
   }
                           
   void updateVTableCache(const Entry &entry);
diff --git a/include/swift/SIL/SILValue.h b/include/swift/SIL/SILValue.h
index 085a3559d2f5f..660ff93ab1c2b 100644
--- a/include/swift/SIL/SILValue.h
+++ b/include/swift/SIL/SILValue.h
@@ -353,6 +353,30 @@ struct ValueOwnershipKind {
                       });
   }
 
+  // An initialized value whose nominal type has a deinit() must be 'owned'. For
+  // example, an owned struct/enum-with-deinit may be initialized by
+  // "forwarding" a trivial value. A struct/enum-with-deinit must be prevented
+  // from forwarding a guaranteed value.
+  //
+  // Simply consider all non-Copyable types to be 'owned'. This could instead be
+  // limited to isValueTypeWithDeinit(). However, forcing non-Copyable types to
+  // be owned is consistent with the fact that their type is non-Trivial and
+  // simplifies reasoning about non-Copyable ownership.
+  ValueOwnershipKind forwardToInit(SILType nominalType) {
+    if (nominalType.isMoveOnly()) {
+      switch (value) {
+      case OwnershipKind::Any:
+      case OwnershipKind::None:
+      case OwnershipKind::Owned:
+        return OwnershipKind::Owned;
+      case OwnershipKind::Guaranteed:
+      case OwnershipKind::Unowned:
+        ABORT("Cannot initialize a nonCopyable type with a guaranteed value");
+      }
+    }
+    return *this;
+  }
+
   StringRef asString() const;
 };
 
@@ -592,6 +616,8 @@ class ValueBase : public SILNode, public SILAllocated<ValueBase> {
 
   bool isBeginApplyToken() const;
 
+  bool isBorrowAccessorResult() const;
+
   /// Unsafely eliminate moveonly from this value's type. Returns true if the
   /// value's underlying type was move only and thus was changed. Returns false
   /// otherwise.
diff --git a/include/swift/SIL/SILWitnessTable.h b/include/swift/SIL/SILWitnessTable.h
index 39bc3c05110f1..a76ef040c923d 100644
--- a/include/swift/SIL/SILWitnessTable.h
+++ b/include/swift/SIL/SILWitnessTable.h
@@ -66,8 +66,6 @@ class SILWitnessTable : public llvm::ilist_node<SILWitnessTable>,
   struct AssociatedConformanceWitness {
     /// The subject type of the associated requirement.
     CanType Requirement;
-    /// FIXME: Temporary.
-    CanType SubstType;
     /// The ProtocolConformanceRef satisfying the requirement.
     ProtocolConformanceRef Witness;
   };
@@ -154,15 +152,6 @@ class SILWitnessTable : public llvm::ilist_node<SILWitnessTable>,
                const PrintOptions &options) const;
   };
 
-  /// An entry for a conformance requirement that makes the requirement
-  /// conditional. These aren't public, but any witness thunks need to feed them
-  /// into the true witness functions.
-  struct ConditionalConformance {
-    /// FIXME: Temporary.
-    CanType Requirement;
-    ProtocolConformanceRef Conformance;
-  };
-
 private:
   /// The module which contains the SILWitnessTable.
   SILModule &Mod;
@@ -186,13 +175,15 @@ class SILWitnessTable : public llvm::ilist_node<SILWitnessTable>,
   ///
   /// (If other private entities are introduced this could/should be switched
   /// into a private version of Entries.)
-  MutableArrayRef<ConditionalConformance> ConditionalConformances;
+  MutableArrayRef<ProtocolConformanceRef> ConditionalConformances;
 
   /// Whether or not this witness table is a declaration. This is separate from
   /// whether or not entries is empty since you can have an empty witness table
   /// that is not a declaration.
   bool IsDeclaration;
- 
+
+  bool specialized;
+
   /// Whether or not this witness table is serialized, which allows
   /// devirtualization from another module.
   unsigned SerializedKind : 2;
@@ -201,11 +192,12 @@ class SILWitnessTable : public llvm::ilist_node<SILWitnessTable>,
   SILWitnessTable(SILModule &M, SILLinkage Linkage, SerializedKind_t Serialized,
                   StringRef name, ProtocolConformance *conformance,
                   ArrayRef<Entry> entries,
-                  ArrayRef<ConditionalConformance> conditionalConformances);
+                  ArrayRef<ProtocolConformanceRef> conditionalConformances,
+                  bool specialized);
 
   /// Private constructor for making SILWitnessTable declarations.
   SILWitnessTable(SILModule &M, SILLinkage Linkage, StringRef Name,
-                  ProtocolConformance *conformance);
+                  ProtocolConformance *conformance, bool specialized);
 
   void addWitnessTable();
 
@@ -214,11 +206,13 @@ class SILWitnessTable : public llvm::ilist_node<SILWitnessTable>,
   static SILWitnessTable *
   create(SILModule &M, SILLinkage Linkage, SerializedKind_t SerializedKind,
          ProtocolConformance *conformance, ArrayRef<Entry> entries,
-         ArrayRef<ConditionalConformance> conditionalConformances);
+         ArrayRef<ProtocolConformanceRef> conditionalConformances,
+         bool specialized);
 
   /// Create a new SILWitnessTable declaration.
   static SILWitnessTable *create(SILModule &M, SILLinkage Linkage,
-                                 ProtocolConformance *conformance);
+                                 ProtocolConformance *conformance,
+                                 bool specialized);
 
   ~SILWitnessTable();
   
@@ -249,6 +243,9 @@ class SILWitnessTable : public llvm::ilist_node<SILWitnessTable>,
   /// Returns true if this witness table is a definition.
   bool isDefinition() const { return !isDeclaration(); }
 
+  // Returns true, if this is a specialized witness table (currently only used in embedded mode).
+  bool isSpecialized() const { return specialized; }
+
   /// Returns true if this witness table is going to be (or was) serialized.
   bool isSerialized() const {
     return SerializedKind_t(SerializedKind) == IsSerialized;
@@ -271,7 +268,7 @@ class SILWitnessTable : public llvm::ilist_node<SILWitnessTable>,
   ArrayRef<Entry> getEntries() const { return Entries; }
 
   /// Return all of the conditional conformances.
-  ArrayRef<ConditionalConformance> getConditionalConformances() const {
+  ArrayRef<ProtocolConformanceRef> getConditionalConformances() const {
     return ConditionalConformances;
   }
 
@@ -300,7 +297,7 @@ class SILWitnessTable : public llvm::ilist_node<SILWitnessTable>,
   /// Change a SILWitnessTable declaration into a SILWitnessTable definition.
   void
   convertToDefinition(ArrayRef<Entry> newEntries,
-                      ArrayRef<ConditionalConformance> conditionalConformances,
+                      ArrayRef<ProtocolConformanceRef> conditionalConformances,
                       SerializedKind_t serializedKind);
 
   // Gets conformance serialized kind.
diff --git a/include/swift/SIL/SILWitnessVisitor.h b/include/swift/SIL/SILWitnessVisitor.h
index 088346727d090..d5f7feb3ed449 100644
--- a/include/swift/SIL/SILWitnessVisitor.h
+++ b/include/swift/SIL/SILWitnessVisitor.h
@@ -100,7 +100,7 @@ template <class T> class SILWitnessVisitor : public ASTVisitor<T> {
       // If this is a new associated type (which does not override an
       // existing associated type), add it.
       if (associatedType->getOverriddenDecls().empty())
-        asDerived().addAssociatedType(AssociatedType(associatedType));
+        asDerived().addAssociatedType(associatedType);
     }
 
     if (asDerived().shouldVisitRequirementSignatureOnly())
diff --git a/include/swift/SIL/TerminatorUtils.h b/include/swift/SIL/TerminatorUtils.h
index 6481d8c77de8f..ecae43e9a23d4 100644
--- a/include/swift/SIL/TerminatorUtils.h
+++ b/include/swift/SIL/TerminatorUtils.h
@@ -56,19 +56,19 @@ class SwitchEnumTermInst {
   operator TermInst *() const {
     if (auto *seai = value.dyn_cast<SwitchEnumAddrInst *>())
       return seai;
-    return value.get<SwitchEnumInst *>();
+    return cast<SwitchEnumInst *>(value);
   }
 
   TermInst *operator*() const {
     if (auto *seai = value.dyn_cast<SwitchEnumAddrInst *>())
       return seai;
-    return value.get<SwitchEnumInst *>();
+    return cast<SwitchEnumInst *>(value);
   }
 
   TermInst *operator->() const {
     if (auto *seai = value.dyn_cast<SwitchEnumAddrInst *>())
       return seai;
-    return value.get<SwitchEnumInst *>();
+    return cast<SwitchEnumInst *>(value);
   }
 
   operator bool() const { return bool(value); }
@@ -76,62 +76,62 @@ class SwitchEnumTermInst {
   SILValue getOperand() {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getOperand();
-    return value.get<SwitchEnumAddrInst *>()->getOperand();
+    return cast<SwitchEnumAddrInst *>(value)->getOperand();
   }
 
   unsigned getNumCases() {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getNumCases();
-    return value.get<SwitchEnumAddrInst *>()->getNumCases();
+    return cast<SwitchEnumAddrInst *>(value)->getNumCases();
   }
 
   std::pair<EnumElementDecl *, SILBasicBlock *> getCase(unsigned i) const {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getCase(i);
-    return value.get<SwitchEnumAddrInst *>()->getCase(i);
+    return cast<SwitchEnumAddrInst *>(value)->getCase(i);
   }
 
   SILBasicBlock *getCaseDestination(EnumElementDecl *decl) const {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getCaseDestination(decl);
-    return value.get<SwitchEnumAddrInst *>()->getCaseDestination(decl);
+    return cast<SwitchEnumAddrInst *>(value)->getCaseDestination(decl);
   }
 
   ProfileCounter getCaseCount(unsigned i) const {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getCaseCount(i);
-    return value.get<SwitchEnumAddrInst *>()->getCaseCount(i);
+    return cast<SwitchEnumAddrInst *>(value)->getCaseCount(i);
   }
 
   ProfileCounter getDefaultCount() const {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getDefaultCount();
-    return value.get<SwitchEnumAddrInst *>()->getDefaultCount();
+    return cast<SwitchEnumAddrInst *>(value)->getDefaultCount();
   }
 
   bool hasDefault() const {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->hasDefault();
-    return value.get<SwitchEnumAddrInst *>()->hasDefault();
+    return cast<SwitchEnumAddrInst *>(value)->hasDefault();
   }
 
   SILBasicBlock *getDefaultBB() const {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getDefaultBB();
-    return value.get<SwitchEnumAddrInst *>()->getDefaultBB();
+    return cast<SwitchEnumAddrInst *>(value)->getDefaultBB();
   }
 
   NullablePtr<SILBasicBlock> getDefaultBBOrNull() const {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getDefaultBBOrNull();
-    return value.get<SwitchEnumAddrInst *>()->getDefaultBBOrNull();
+    return cast<SwitchEnumAddrInst *>(value)->getDefaultBBOrNull();
   }
 
   /// If the default refers to exactly one case decl, return it.
   NullablePtr<EnumElementDecl> getUniqueCaseForDefault() const {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getUniqueCaseForDefault();
-    return value.get<SwitchEnumAddrInst *>()->getUniqueCaseForDefault();
+    return cast<SwitchEnumAddrInst *>(value)->getUniqueCaseForDefault();
   }
 
   /// If the given block only has one enum element decl matched to it,
@@ -140,7 +140,7 @@ class SwitchEnumTermInst {
   getUniqueCaseForDestination(SILBasicBlock *BB) const {
     if (auto *sei = value.dyn_cast<SwitchEnumInst *>())
       return sei->getUniqueCaseForDestination(BB);
-    return value.get<SwitchEnumAddrInst *>()->getUniqueCaseForDestination(BB);
+    return cast<SwitchEnumAddrInst *>(value)->getUniqueCaseForDestination(BB);
   }
 };
 
diff --git a/include/swift/SIL/Test.h b/include/swift/SIL/Test.h
index 7acac7d5f862e..47124ffd57fd6 100644
--- a/include/swift/SIL/Test.h
+++ b/include/swift/SIL/Test.h
@@ -141,6 +141,8 @@ class FunctionTest final {
   /// The lambda to be run.
   TaggedUnion<Invocation, NativeSwiftInvocation> invocation;
 
+  bool isSwiftSILTest = false;
+
 public:
   /// Creates a test that will run \p invocation and stores it in the global
   /// registry.
@@ -158,7 +160,8 @@ class FunctionTest final {
   /// Creates a test that will run \p invocation and stores it in the global
   /// registry.
   static void createNativeSwiftFunctionTest(StringRef name,
-                                            NativeSwiftInvocation invocation);
+                                            NativeSwiftInvocation invocation,
+                                            bool isSILTest);
 
   /// Computes and returns the function's dominance tree.
   DominanceInfo *getDominanceInfo();
@@ -179,7 +182,7 @@ class FunctionTest final {
 
   SILFunctionTransform *getPass();
 
-  SwiftPassInvocation *getSwiftPassInvocation();
+  SILContext *getSILContext();
 
 //===----------------------------------------------------------------------===//
 //=== MARK: Implementation Details                                         ===
@@ -260,7 +263,7 @@ class FunctionTest final {
     virtual DominanceInfo *getDominanceInfo() = 0;
     virtual DeadEndBlocks *getDeadEndBlocks() = 0;
     virtual SILPassManager *getPassManager() = 0;
-    virtual SwiftPassInvocation *getSwiftPassInvocation() = 0;
+    virtual SILContext *getSILContext() = 0;
     virtual ~Dependencies(){};
   };
 
@@ -271,7 +274,7 @@ class FunctionTest final {
 public:
   /// Creates a test that will run \p invocation.  For use by
   /// createNativeSwiftFunctionTest.
-  FunctionTest(StringRef name, NativeSwiftInvocation invocation);
+  FunctionTest(StringRef name, NativeSwiftInvocation invocation, bool isSILTest);
 };
 
 /// Thunks for delaying template instantiation.
diff --git a/include/swift/SIL/TypeLowering.h b/include/swift/SIL/TypeLowering.h
index 6859c87bf37e3..3cf6e735115ba 100644
--- a/include/swift/SIL/TypeLowering.h
+++ b/include/swift/SIL/TypeLowering.h
@@ -20,6 +20,7 @@
 #include "swift/SIL/SILDeclRef.h"
 #include "swift/SIL/SILInstruction.h"
 #include "swift/SIL/SILLocation.h"
+#include "swift/SIL/SILTypeProperties.h"
 #include "swift/SIL/SILValue.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Hashing.h"
@@ -92,240 +93,8 @@ adjustFunctionType(CanSILFunctionType t, SILFunctionType::Representation rep,
                             witnessMethodConformance);
 }
 
-/// Is a lowered SIL type trivial?  That is, are copies ultimately just
-/// bit-copies, and it takes no work to destroy a value?
-enum IsTrivial_t : bool {
-  IsNotTrivial = false,
-  IsTrivial = true
-};
-
-/// Is a lowered SIL type the Builtin.RawPointer or a struct/tuple/enum which
-/// contains a Builtin.RawPointer?
-/// HasRawPointer is true only for types that are known to contain
-/// Builtin.RawPointer. It is not assumed true for generic or resilient types.
-enum HasRawPointer_t : bool {
-  DoesNotHaveRawPointer = false,
-  HasRawPointer = true
-};
-
-/// Is a lowered SIL type fixed-ABI?  That is, can the current context
-/// assign it a fixed size and alignment and perform value operations on it
-/// (such as copies, destroys, constructions, and projections) without
-/// metadata?
-///
-/// Note that a fully concrete type can be non-fixed-ABI without being
-/// itself resilient if it contains a subobject which is not fixed-ABI.
-///
-/// Also note that we're only concerned with the external value ABI here:
-/// resilient class types are still fixed-ABI, indirect enum cases do not
-/// affect the fixed-ABI-ness of the enum, and so on.
-enum IsFixedABI_t : bool {
-  IsNotFixedABI = false,
-  IsFixedABI = true
-};
-
-/// Is a lowered SIL type address-only?  That is, is the current context
-/// required to keep the value in memory for some reason?
-///
-/// A type might be address-only because:
-///
-///   - it is not fixed-size (e.g. because it is a resilient type) and
-///     therefore cannot be loaded into a statically-boundable set of
-///     registers; or
-///
-///   - it is semantically bound to memory, either because its storage
-///     address is used by the language runtime to implement its semantics
-///     (as with a weak reference) or because its representation is somehow
-///     address-dependent (as with something like a relative pointer).
-///
-/// An address-only type can be fixed-layout and/or trivial.
-/// A non-fixed-layout type is always address-only.
-enum IsAddressOnly_t : bool {
-  IsNotAddressOnly = false,
-  IsAddressOnly = true
-};
-
-/// Is this type somewhat like a reference-counted type?
-enum IsReferenceCounted_t : bool {
-  IsNotReferenceCounted = false,
-  IsReferenceCounted = true
-};
-
-/// Is this type address only because it's resilient?
-enum IsResilient_t : bool {
-  IsNotResilient = false,
-  IsResilient = true
-};
-
-/// Does this type contain an opaque result type that affects type lowering?
-enum IsTypeExpansionSensitive_t : bool {
-  IsNotTypeExpansionSensitive = false,
-  IsTypeExpansionSensitive = true
-};
-
-/// Is the type infinitely defined in terms of itself? (Such types can never
-/// be concretely instantiated, but may still arise from generic specialization.)
-enum IsInfiniteType_t : bool {
-  IsNotInfiniteType = false,
-  IsInfiniteType = true,
-};
-
-/// Does this type contain any pack-like thing.
-enum HasPack_t : bool {
-  HasNoPack = false,
-  HasPack = true,
-};
-
-/// Is the type addressable-for-dependencies?
-///
-/// Values of an addressable-for-dependency type are passed indirectly into
-/// functions that specify a return value lifetime dependency on the value.
-/// This allows the dependent value to safely contain pointers to the in-memory
-/// representation of the source of the dependency.
-enum IsAddressableForDependencies_t : bool {
-  IsNotAddressableForDependencies = false,
-  IsAddressableForDependencies = true,
-};
-
 /// Extended type information used by SIL.
 class TypeLowering {
-public:
-  class RecursiveProperties {
-    // These are chosen so that bitwise-or merges the flags properly.
-    //
-    // clang-format off
-    enum : unsigned {
-      NonTrivialFlag                 = 1 << 0,
-      NonFixedABIFlag                = 1 << 1,
-      AddressOnlyFlag                = 1 << 2,
-      ResilientFlag                  = 1 << 3,
-      TypeExpansionSensitiveFlag     = 1 << 4,
-      InfiniteFlag                   = 1 << 5,
-      HasRawPointerFlag              = 1 << 6,
-      LexicalFlag                    = 1 << 7,
-      HasPackFlag                    = 1 << 8,
-      AddressableForDependenciesFlag = 1 << 9,
-    };
-    // clang-format on
-
-    uint16_t Flags;
-
-  public:
-    /// Construct a default RecursiveProperties, which corresponds to
-    /// a trivial, loadable, fixed-layout type.
-    constexpr RecursiveProperties() : Flags(0) {}
-
-    constexpr RecursiveProperties(
-        IsTrivial_t isTrivial, IsFixedABI_t isFixedABI,
-        IsAddressOnly_t isAddressOnly, IsResilient_t isResilient,
-        IsTypeExpansionSensitive_t isTypeExpansionSensitive =
-            IsNotTypeExpansionSensitive,
-        HasRawPointer_t hasRawPointer = DoesNotHaveRawPointer,
-        IsLexical_t isLexical = IsNotLexical, HasPack_t hasPack = HasNoPack,
-        IsAddressableForDependencies_t isAFD = IsNotAddressableForDependencies)
-        : Flags((isTrivial ? 0U : NonTrivialFlag) |
-                (isFixedABI ? 0U : NonFixedABIFlag) |
-                (isAddressOnly ? AddressOnlyFlag : 0U) |
-                (isResilient ? ResilientFlag : 0U) |
-                (isTypeExpansionSensitive ? TypeExpansionSensitiveFlag : 0U) |
-                (hasRawPointer ? HasRawPointerFlag : 0U) |
-                (isLexical ? LexicalFlag : 0U) |
-                (hasPack ? HasPackFlag : 0U) |
-                (isAFD ? AddressableForDependenciesFlag : 0U)) {}
-
-    constexpr bool operator==(RecursiveProperties p) const {
-      return Flags == p.Flags;
-    }
-
-    static constexpr RecursiveProperties forTrivial() {
-      return {IsTrivial, IsFixedABI, IsNotAddressOnly, IsNotResilient};
-    }
-
-    static constexpr RecursiveProperties forTrivialOpaque() {
-      return {IsTrivial, IsFixedABI, IsNotAddressOnly, IsNotResilient,
-              IsNotTypeExpansionSensitive, HasRawPointer, IsNotLexical,
-              HasNoPack, IsAddressableForDependencies};
-    }
-
-    static constexpr RecursiveProperties forRawPointer() {
-      return {IsTrivial, IsFixedABI, IsNotAddressOnly, IsNotResilient,
-              IsNotTypeExpansionSensitive, HasRawPointer};
-    }
-
-    static constexpr RecursiveProperties forReference() {
-      return {IsNotTrivial, IsFixedABI, IsNotAddressOnly, IsNotResilient,
-              IsNotTypeExpansionSensitive, DoesNotHaveRawPointer, IsLexical};
-    }
-
-    static constexpr RecursiveProperties forOpaque() {
-      return {IsNotTrivial, IsNotFixedABI, IsAddressOnly, IsNotResilient,
-              IsNotTypeExpansionSensitive, HasRawPointer, IsLexical,
-              HasNoPack, IsAddressableForDependencies};
-    }
-
-    static constexpr RecursiveProperties forResilient() {
-      return {IsTrivial, IsFixedABI, IsNotAddressOnly, IsResilient,
-              IsNotTypeExpansionSensitive, HasRawPointer, IsNotLexical,
-              HasNoPack, IsAddressableForDependencies};
-    }
-
-    void addSubobject(RecursiveProperties other) {
-      Flags |= other.Flags;
-    }
-
-    IsTrivial_t isTrivial() const {
-      return IsTrivial_t((Flags & NonTrivialFlag) == 0);
-    }
-    HasRawPointer_t isOrContainsRawPointer() const {
-      return HasRawPointer_t((Flags & HasRawPointerFlag) != 0);
-    }
-    IsFixedABI_t isFixedABI() const {
-      return IsFixedABI_t((Flags & NonFixedABIFlag) == 0);
-    }
-    IsAddressOnly_t isAddressOnly() const {
-      return IsAddressOnly_t((Flags & AddressOnlyFlag) != 0);
-    }
-    IsResilient_t isResilient() const {
-      return IsResilient_t((Flags & ResilientFlag) != 0);
-    }
-    IsTypeExpansionSensitive_t isTypeExpansionSensitive() const {
-      return IsTypeExpansionSensitive_t(
-          (Flags & TypeExpansionSensitiveFlag) != 0);
-    }
-    IsInfiniteType_t isInfinite() const {
-      return IsInfiniteType_t((Flags & InfiniteFlag) != 0);
-    }
-    IsLexical_t isLexical() const {
-      return IsLexical_t((Flags & LexicalFlag) != 0);
-    }
-    HasPack_t isOrContainsPack() const {
-      return HasPack_t((Flags & HasPackFlag) != 0);
-    }
-    IsAddressableForDependencies_t isAddressableForDependencies() const {
-      return IsAddressableForDependencies_t(
-                                (Flags & AddressableForDependenciesFlag) != 0);
-    }
-
-    void setNonTrivial() { Flags |= NonTrivialFlag; }
-    void setIsOrContainsRawPointer() { Flags |= HasRawPointerFlag; }
-
-    void setNonFixedABI() { Flags |= NonFixedABIFlag; }
-    void setAddressOnly() { Flags |= AddressOnlyFlag; }
-    void setTypeExpansionSensitive(
-        IsTypeExpansionSensitive_t isTypeExpansionSensitive) {
-      Flags = (Flags & ~TypeExpansionSensitiveFlag) |
-              (isTypeExpansionSensitive ? TypeExpansionSensitiveFlag : 0);
-    }
-    void setInfinite() { Flags |= InfiniteFlag; }
-    void setLexical(IsLexical_t isLexical) {
-      Flags = (Flags & ~LexicalFlag) | (isLexical ? LexicalFlag : 0);
-    }
-    void setHasPack() { Flags |= HasPackFlag; }
-    void setAddressableForDependencies() {
-      Flags |= AddressableForDependenciesFlag;
-    }
-  };
-
 private:
   friend class TypeConverter;
 
@@ -336,7 +105,7 @@ class TypeLowering {
   mutable SILType LoweredType;
 
 private:
-  RecursiveProperties Properties;
+  SILTypeProperties Properties;
 
   /// The resilience expansion for this type lowering.
   /// If the type is not resilient at all, this is always Minimal.
@@ -349,7 +118,7 @@ class TypeLowering {
   mutable const TypeLowering *NextExpansion = nullptr;
 
 protected:
-  TypeLowering(SILType type, RecursiveProperties properties,
+  TypeLowering(SILType type, SILTypeProperties properties,
                IsReferenceCounted_t isRefCounted,
                TypeExpansionContext expansionContext)
       : LoweredType(type), Properties(properties),
@@ -367,7 +136,7 @@ class TypeLowering {
   /// Dump out the internal state of this type lowering to llvm::dbgs().
   SWIFT_DEBUG_DUMP;
 
-  RecursiveProperties getRecursiveProperties() const {
+  SILTypeProperties getRecursiveProperties() const {
     return Properties;
   }
 
@@ -382,7 +151,7 @@ class TypeLowering {
   /// full layout is available to the compiler. This is the inverse of
   /// isAddressOnly.
   bool isLoadable() const {
-    return !isAddressOnly();
+    return Properties.isLoadable();
   }
 
   /// isFixedABI - Returns true if the type has a known fixed layout.
@@ -1071,6 +840,14 @@ class TypeConverter {
     return ti.getLoweredType();
   }
 
+  SILTypeProperties getTypeProperties(AbstractionPattern origType,
+                                      Type substType,
+                                      TypeExpansionContext forExpansion);
+  SILTypeProperties getTypeProperties(Type substType,
+                                      TypeExpansionContext forExpansion);
+  SILTypeProperties getTypeProperties(SILType type,
+                                      TypeExpansionContext forExpansion);
+
   CanType getLoweredRValueType(TypeExpansionContext context, Type t) {
     return getLoweredType(t, context).getRawASTType();
   }
@@ -1389,6 +1166,14 @@ CanSILFunctionType getNativeSILFunctionType(
     std::optional<SubstitutionMap> reqtSubs = std::nullopt,
     ProtocolConformanceRef witnessMethodConformance = ProtocolConformanceRef());
 
+/// origConstant is the parent decl ref in the case of class methods and the
+/// witness method decl ref if we are working with a protocol witness. Pass in
+/// None otherwise.
+std::optional<ActorIsolation>
+getSILFunctionTypeActorIsolation(CanAnyFunctionType substFnInterfaceType,
+                                 std::optional<SILDeclRef> origConstant,
+                                 std::optional<SILDeclRef> constant);
+
 /// The thunk kinds used in the differentiation transform.
 enum class DifferentiationThunkKind {
   /// A reabstraction thunk.
diff --git a/include/swift/SIL/TypeSubstCloner.h b/include/swift/SIL/TypeSubstCloner.h
index a9e5ca25b4419..d7573487791d9 100644
--- a/include/swift/SIL/TypeSubstCloner.h
+++ b/include/swift/SIL/TypeSubstCloner.h
@@ -36,7 +36,7 @@ namespace swift {
 /// subclasses. Used to break a circular dependency from SIL <=>
 /// SILOptimizer that would be caused by us needing to use
 /// SILOptFunctionBuilder here.
-template<typename ImplClass, typename FunctionBuilderTy>
+template<typename ImplClass>
 class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
   friend class SILInstructionVisitor<ImplClass>;
   friend class SILCloner<ImplClass>;
@@ -244,10 +244,11 @@ class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
     auto FalseCount = inst->getFalseBBCount();
 
     // Try to use the scalar cast instruction.
-    if (canSILUseScalarCheckedCastInstructions(B.getModule(),
-                                               sourceType, targetType)) {
+    if (canOptimizeToScalarCheckedCastInstructions(
+            &B.getFunction(), sourceType, targetType,
+            inst->getConsumptionKind())) {
       emitIndirectConditionalCastWithScalar(
-          B, SwiftMod, loc, inst->getIsolatedConformances(),
+          B, SwiftMod, loc, inst->getCheckedCastOptions(),
           inst->getConsumptionKind(), src, sourceType, dest,
           targetType, succBB, failBB, TrueCount, FalseCount);
       return;
@@ -255,7 +256,7 @@ class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
 
     // Otherwise, use the indirect cast.
     B.createCheckedCastAddrBranch(loc,
-                                  inst->getIsolatedConformances(),
+                                  inst->getCheckedCastOptions(),
                                   inst->getConsumptionKind(),
                                   src, sourceType,
                                   dest, targetType,
@@ -284,6 +285,16 @@ class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
     super::visitCopyValueInst(Copy);
   }
 
+  void visitExplicitCopyValueInst(ExplicitCopyValueInst *Copy) {
+    // If the substituted type is trivial, ignore the copy.
+    SILType copyTy = getOpType(Copy->getType());
+    if (copyTy.isTrivial(*Copy->getFunction())) {
+      recordFoldedValue(SILValue(Copy), getOpValue(Copy->getOperand()));
+      return;
+    }
+    super::visitExplicitCopyValueInst(Copy);
+  }
+
   void visitDestroyValueInst(DestroyValueInst *Destroy) {
     // If the substituted type is trivial, ignore the destroy.
     SILType destroyTy = getOpType(Destroy->getOperand()->getType());
@@ -293,6 +304,24 @@ class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
     super::visitDestroyValueInst(Destroy);
   }
 
+  void visitEndLifetimeInst(EndLifetimeInst *endLifetime) {
+    // If the substituted type is trivial, ignore the end_lifetime.
+    SILType ty = getOpType(endLifetime->getOperand()->getType());
+    if (ty.isTrivial(*endLifetime->getFunction())) {
+      return;
+    }
+    super::visitEndLifetimeInst(endLifetime);
+  }
+
+  void visitExtendLifetimeInst(ExtendLifetimeInst *extendLifetime) {
+    // If the substituted type is trivial, ignore the extend_lifetime.
+    SILType ty = getOpType(extendLifetime->getOperand()->getType());
+    if (ty.isTrivial(*extendLifetime->getFunction())) {
+      return;
+    }
+    super::visitExtendLifetimeInst(extendLifetime);
+  }
+
   void visitDifferentiableFunctionExtractInst(
       DifferentiableFunctionExtractInst *dfei) {
     // If the extractee is the original function, do regular cloning.
@@ -355,22 +384,40 @@ class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
   enum { ForInlining = true };
   /// Helper function to clone the parent function of a SILDebugScope if
   /// necessary when inlining said function into a new generic context.
-  /// \param SubsMap - the substitutions of the inlining/specialization process.
-  /// \param RemappedSig - the generic signature.
+  /// \param SubsMap - the substitutions for the call to the callee.
+  /// \param CalleeSig - the callee generic signature.
+  template<typename FunctionBuilderTy>
   static SILFunction *remapParentFunction(FunctionBuilderTy &FuncBuilder,
                                           SILModule &M,
                                           SILFunction *ParentFunction,
                                           SubstitutionMap SubsMap,
-                                          GenericSignature RemappedSig,
+                                          GenericSignature CalleeSig,
                                           bool ForInlining = false) {
     // If the original, non-inlined version of the function had no generic
     // environment, there is no need to remap it.
-    auto *OriginalEnvironment = ParentFunction->getGenericEnvironment();
-    if (!RemappedSig || !OriginalEnvironment)
+    auto *CalleeEnv = ParentFunction->getGenericEnvironment();
+    if (!CalleeSig || !CalleeEnv)
       return ParentFunction;
 
-    if (SubsMap.getRecursiveProperties().hasPrimaryArchetype())
+    // FIXME: Pass the CallerSig down directly instead of doing this.
+    GenericSignature CallerSig;
+    if (SubsMap.getRecursiveProperties().hasPrimaryArchetype()) {
+      for (auto ReplacementType : SubsMap.getReplacementTypes()) {
+        ReplacementType.visit([&](Type t) {
+          if (t->is<PrimaryArchetypeType>() || t->is<PackArchetypeType>()) {
+            auto sig =
+              t->castTo<ArchetypeType>()->getGenericEnvironment()
+                ->getGenericSignature();
+            if (!CallerSig)
+              CallerSig = sig;
+            else
+              ASSERT(CallerSig.getPointer() == sig.getPointer());
+          }
+        });
+      }
+
       SubsMap = SubsMap.mapReplacementTypesOutOfContext();
+    }
 
     // One abstract function in the debug info can only have one set of variables
     // and types. We check if the function is called with non-identity substitutions
@@ -389,7 +436,7 @@ class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
     Mangle::GenericSpecializationMangler Mangler(M.getASTContext(), ParentFunction,
                                                  IsNotSerialized);
     std::string MangledName =
-      Mangler.mangleForDebugInfo(RemappedSig, SubsMap, ForInlining);
+      Mangler.mangleForDebugInfo(CalleeSig, SubsMap, CallerSig, ForInlining);
 
     if (ParentFunction->getName() == MangledName)
       return ParentFunction;
@@ -413,7 +460,7 @@ class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
         // undead.
         if (ParentFunction->empty()) {
           FuncBuilder.eraseFunction(ParentFunction);
-          ParentFunction->setGenericEnvironment(OriginalEnvironment);
+          ParentFunction->setGenericEnvironment(CalleeEnv);
         }
       }
     }
diff --git a/include/swift/SILOptimizer/Analysis/Analysis.h b/include/swift/SILOptimizer/Analysis/Analysis.h
index a0647818b0418..deed38a88d6e5 100644
--- a/include/swift/SILOptimizer/Analysis/Analysis.h
+++ b/include/swift/SILOptimizer/Analysis/Analysis.h
@@ -15,6 +15,8 @@
 
 #include "swift/Basic/NullablePtr.h"
 #include "swift/SIL/Notifications.h"
+#include "swift/SIL/SILModule.h"
+#include "swift/SIL/SILContext.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/Support/Casting.h"
 
@@ -49,25 +51,25 @@ class SILAnalysis {
 
     /// The pass created, deleted or rearranged some instructions in a
     /// function.
-    Instructions = 0x1,
+    Instructions = SILContext::NotificationKind::Instructions,
 
     /// The pass modified some calls (apply instructions).
     ///
     /// The intention of this invalidation kind is to allow analysis that
     /// rely on a specific call graph structure to recompute themselves.
-    Calls = 0x2,
+    Calls = SILContext::NotificationKind::Calls,
 
     /// A pass has invalidated some branches in the program.
     ///
     /// The intention of this invalidation kind is to tell analyses like the
     /// Dominance Analysis and the PostOrder Analysis that the underlying CFG
     /// has been modified.
-    Branches = 0x4,
+    Branches = SILContext::NotificationKind::Branches,
 
     /// The function effects.
     ///
     /// The computed effects of the function are invalidated.
-    Effects = 0x8,
+    Effects = SILContext::NotificationKind::Effects,
 
     /// Convenience states:
     FunctionBody = Calls | Branches | Instructions,
@@ -231,19 +233,19 @@ class FunctionAnalysisBase : public SILAnalysis {
     // Check that the analysis can handle this function.
     verifyFunction(f);
 
-    auto &it = storage.FindAndConstruct(f);
-    if (!it.second)
-      it.second = newFunctionAnalysis(f);
-    return it.second.get();
+    auto &value = storage[f];
+    if (!value)
+      value = newFunctionAnalysis(f);
+    return value.get();
   }
 
   virtual void forcePrecompute(SILFunction *f) override {
     // Check that the analysis can handle this function.
     verifyFunction(f);
 
-    auto &it = storage.FindAndConstruct(f);
-    if (!it.second)
-      it.second = newFunctionAnalysis(f);
+    auto &value = storage[f];
+    if (!value)
+      value = newFunctionAnalysis(f);
   }
 
   /// Invalidate all information in this analysis.
diff --git a/include/swift/SILOptimizer/Analysis/ArrayCallKind.h b/include/swift/SILOptimizer/Analysis/ArrayCallKind.h
new file mode 100644
index 0000000000000..f3db620d0d162
--- /dev/null
+++ b/include/swift/SILOptimizer/Analysis/ArrayCallKind.h
@@ -0,0 +1,45 @@
+//===--- ArrayCallKind.h -------------------------------------- -*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ARRAY_CALL_KIND_H
+#define ARRAY_CALL_KIND_H
+
+/// The kind of array operation identified by looking at the semantics attribute
+/// of the called function.
+enum class ArrayCallKind {
+  kNone = 0,
+  kArrayPropsIsNativeTypeChecked,
+  kCheckSubscript,
+  kCheckIndex,
+  kGetCount,
+  kGetCapacity,
+  kGetElement,
+  kGetElementAddress,
+  kMakeMutable,
+  kEndMutation,
+  kMutateUnknown,
+  kReserveCapacityForAppend,
+  kWithUnsafeMutableBufferPointer,
+  kAppendContentsOf,
+  kAppendElement,
+  // The following two semantic function kinds return the result @owned
+  // instead of operating on self passed as parameter. If you are adding
+  // a function, and it has a self parameter, make sure that it is defined
+  // before this comment.
+  kArrayInit,
+  kArrayInitEmpty,
+  kArrayUninitialized,
+  kArrayUninitializedIntrinsic,
+  kArrayFinalizeIntrinsic
+};
+
+#endif
diff --git a/include/swift/SILOptimizer/Analysis/ArraySemantic.h b/include/swift/SILOptimizer/Analysis/ArraySemantic.h
index 7bbca9d7c7e50..0b144562dea94 100644
--- a/include/swift/SILOptimizer/Analysis/ArraySemantic.h
+++ b/include/swift/SILOptimizer/Analysis/ArraySemantic.h
@@ -14,40 +14,12 @@
 #define SWIFT_SILOPTIMIZER_ANALYSIS_ARRAYSEMANTIC_H
 
 #include "swift/SIL/SILInstruction.h"
+#include "swift/SILOptimizer/Analysis/ArrayCallKind.h"
 
 namespace swift {
 
 class DominanceInfo;
 
-/// The kind of array operation identified by looking at the semantics attribute
-/// of the called function.
-enum class ArrayCallKind {
-  kNone = 0,
-  kArrayPropsIsNativeTypeChecked,
-  kCheckSubscript,
-  kCheckIndex,
-  kGetCount,
-  kGetCapacity,
-  kGetElement,
-  kGetElementAddress,
-  kMakeMutable,
-  kEndMutation,
-  kMutateUnknown,
-  kReserveCapacityForAppend,
-  kWithUnsafeMutableBufferPointer,
-  kAppendContentsOf,
-  kAppendElement,
-  // The following two semantic function kinds return the result @owned
-  // instead of operating on self passed as parameter. If you are adding
-  // a function, and it has a self parameter, make sure that it is defined
-  // before this comment.
-  kArrayInit,
-  kArrayInitEmpty,
-  kArrayUninitialized,
-  kArrayUninitializedIntrinsic,
-  kArrayFinalizeIntrinsic
-};
-
 /// Return true is the given function is an array semantics call.
 ArrayCallKind getArraySemanticsKind(SILFunction *f);
 
diff --git a/include/swift/SILOptimizer/Analysis/LoopRegionAnalysis.h b/include/swift/SILOptimizer/Analysis/LoopRegionAnalysis.h
index 3605e821601e5..1e30af6e94668 100644
--- a/include/swift/SILOptimizer/Analysis/LoopRegionAnalysis.h
+++ b/include/swift/SILOptimizer/Analysis/LoopRegionAnalysis.h
@@ -690,9 +690,9 @@ class LoopRegion {
   LoopTy *getLoop() const;
   FunctionTy *getFunction() const;
 
-  bool isBlock() const { return Ptr.is<BlockTy *>(); }
-  bool isLoop() const { return Ptr.is<LoopTy *>(); }
-  bool isFunction() const { return Ptr.is<FunctionTy *>(); }
+  bool isBlock() const { return isa<BlockTy *>(Ptr); }
+  bool isLoop() const { return isa<LoopTy *>(Ptr); }
+  bool isFunction() const { return isa<FunctionTy *>(Ptr); }
 
   /// Is this the head of an edge that causes unknown control flow.
   ///
diff --git a/include/swift/SILOptimizer/Analysis/RegionAnalysis.h b/include/swift/SILOptimizer/Analysis/RegionAnalysis.h
index f21ccd2b31382..190ae1d65693f 100644
--- a/include/swift/SILOptimizer/Analysis/RegionAnalysis.h
+++ b/include/swift/SILOptimizer/Analysis/RegionAnalysis.h
@@ -108,6 +108,7 @@ class BlockPartitionState {
 
 class TrackableValue;
 class TrackableValueState;
+struct TrackableValueLookupResult;
 
 enum class TrackableValueFlag {
   /// Base value that says a value is uniquely represented and is
@@ -178,16 +179,16 @@ class regionanalysisimpl::TrackableValueState {
 
   void removeFlag(TrackableValueFlag flag) { flagSet -= flag; }
 
-  void print(llvm::raw_ostream &os) const {
+  void print(SILFunction *fn, llvm::raw_ostream &os) const {
     os << "TrackableValueState[id: " << id
        << "][is_no_alias: " << (isNoAlias() ? "yes" : "no")
        << "][is_sendable: " << (isSendable() ? "yes" : "no")
        << "][region_value_kind: ";
-    getIsolationRegionInfo().printForOneLineLogging(os);
+    getIsolationRegionInfo().printForOneLineLogging(fn, os);
     os << "].";
   }
 
-  SWIFT_DEBUG_DUMP { print(llvm::dbgs()); }
+  SWIFT_DEBUG_DUMPER(dump(SILFunction *fn)) { print(fn, llvm::dbgs()); }
 
 private:
   bool hasIsolationRegionInfo() const { return bool(regionInfo); }
@@ -248,30 +249,49 @@ class regionanalysisimpl::TrackableValue {
   /// parameter.
   bool isSendingParameter() const;
 
-  void printIsolationInfo(SmallString<64> &outString) const {
+  void printIsolationInfo(SILFunction *fn, SmallString<64> &outString) const {
     llvm::raw_svector_ostream os(outString);
-    getIsolationRegionInfo().printForDiagnostics(os);
+    getIsolationRegionInfo().printForDiagnostics(fn, os);
   }
 
-  void print(llvm::raw_ostream &os) const {
+  void print(SILFunction *fn, llvm::raw_ostream &os) const {
     os << "TrackableValue. State: ";
-    valueState.print(os);
+    valueState.print(fn, os);
     os << "\n    Rep Value: ";
     getRepresentative().print(os);
   }
 
-  void printVerbose(llvm::raw_ostream &os) const {
+  void printVerbose(SILFunction *fn, llvm::raw_ostream &os) const {
     os << "TrackableValue. State: ";
-    valueState.print(os);
+    valueState.print(fn, os);
     os << "\n    Rep Value: " << getRepresentative();
   }
 
-  SWIFT_DEBUG_DUMP {
-    print(llvm::dbgs());
+  SWIFT_DEBUG_DUMPER(dump(SILFunction *fn)) {
+    print(fn, llvm::dbgs());
     llvm::dbgs() << '\n';
   }
 };
 
+/// A class that contains both a lookup value as well as extra metadata about
+/// properties of the original value that we looked up up from that we
+/// discovered as we searched for the lookup value.
+struct regionanalysisimpl::TrackableValueLookupResult {
+  /// The actual value that we are tracking.
+  ///
+  /// If we are tracking a Sendable address that has a non-Sendable base, this
+  /// will be an empty TrackableValue.
+  TrackableValue value;
+
+  /// If we are tracking an address, this is the base trackable value that is
+  /// being tracked. If the base is a Sendable value, then this will be an empty
+  /// TrackableValue.
+  std::optional<TrackableValue> base;
+
+  void print(SILFunction *fn, llvm::raw_ostream &os) const;
+  SWIFT_DEBUG_DUMPER(dumper(SILFunction *fn)) { print(fn, llvm::dbgs()); }
+};
+
 class RegionAnalysis;
 
 class RegionAnalysisValueMap {
@@ -282,6 +302,8 @@ class RegionAnalysisValueMap {
   using Region = PartitionPrimitives::Region;
   using TrackableValue = regionanalysisimpl::TrackableValue;
   using TrackableValueState = regionanalysisimpl::TrackableValueState;
+  using TrackableValueLookupResult =
+      regionanalysisimpl::TrackableValueLookupResult;
 
 private:
   /// A map from the representative of an equivalence class of values to their
@@ -301,30 +323,57 @@ class RegionAnalysisValueMap {
 
   /// State that the value -> representative computation yields to us.
   struct UnderlyingTrackedValueInfo {
+    /// The equivalence class value that we found that should be merged into
+    /// regions.
+    ///
+    /// Always set to a real value.
     SILValue value;
 
-    /// Only used for addresses.
-    std::optional<ActorIsolation> actorIsolation;
+    /// The actual base value that we found if we were looking for an address
+    /// equivilance class and had a non-Sendable base. If we have an object or
+    /// we do not have a separate base, this is SILValue().
+    SILValue base;
 
-    explicit UnderlyingTrackedValueInfo(SILValue value) : value(value) {}
+    /// Constructor for use if we only have either an object or an address
+    /// equivalence class that involves a complete non-Sendable path.
+    explicit UnderlyingTrackedValueInfo(SILValue value) : value(value), base() {
+      assert(value);
+    }
 
-    UnderlyingTrackedValueInfo() : value(), actorIsolation() {}
+    /// Constructor for use with addresses only where we have either:
+    ///
+    /// 1. A sendable address that is used but that has a non-Sendable base that
+    /// we have to insert requires for.
+    ///
+    /// 2. A non-Sendable address that is used but that has a separate
+    /// non-Sendable base due to an access path chain that has a split in
+    /// between the two due to the non-Sendable address being projected out of
+    /// an intervening sendable struct. The struct can be Sendable due to things
+    /// like being global actor isolated or by being marked @unchecked Sendable.
+    explicit UnderlyingTrackedValueInfo(SILValue value, SILValue base)
+        : value(value), base(base) {
+      assert(value);
+      assert(base);
+    }
+    UnderlyingTrackedValueInfo() : value(), base() {}
 
     UnderlyingTrackedValueInfo(const UnderlyingTrackedValueInfo &newVal)
-        : value(newVal.value), actorIsolation(newVal.actorIsolation) {}
+        : value(newVal.value), base(newVal.base) {}
 
     UnderlyingTrackedValueInfo &
     operator=(const UnderlyingTrackedValueInfo &newVal) {
       value = newVal.value;
-      actorIsolation = newVal.actorIsolation;
+      base = newVal.base;
       return *this;
     }
 
-    UnderlyingTrackedValueInfo(SILValue value,
-                               std::optional<ActorIsolation> actorIsolation)
-        : value(value), actorIsolation(actorIsolation) {}
-
     operator bool() const { return value; }
+
+    void print(llvm::raw_ostream &os) const;
+    SWIFT_DEBUG_DUMP {
+      print(llvm::dbgs());
+      llvm::dbgs() << '\n';
+    }
   };
 
   /// A map from a SILValue to its equivalence class representative.
@@ -341,8 +390,10 @@ class RegionAnalysisValueMap {
     return getUnderlyingTrackedValue(value).value;
   }
 
+  SILFunction *getFunction() const { return fn; }
+
   /// Returns the value for this instruction if it isn't a fake "represenative
-  /// value" to inject actor isolatedness. Asserts in such a case.
+  /// value" to inject actor isolation. Asserts in such a case.
   SILValue getRepresentative(Element trackableValueID) const;
 
   /// Returns the value for this instruction. If it is a fake "representative
@@ -350,7 +401,7 @@ class RegionAnalysisValueMap {
   SILValue maybeGetRepresentative(Element trackableValueID) const;
 
   /// Returns the value for this instruction if it isn't a fake "represenative
-  /// value" to inject actor isolatedness. Asserts in such a case.
+  /// value" to inject actor isolation. Asserts in such a case.
   RepresentativeValue getRepresentativeValue(Element trackableValueID) const;
 
   /// Returns the fake "representative value" for this element if it
@@ -363,10 +414,16 @@ class RegionAnalysisValueMap {
   void print(llvm::raw_ostream &os) const;
   SWIFT_DEBUG_DUMP { print(llvm::dbgs()); }
 
-  TrackableValue
+  TrackableValueLookupResult
   getTrackableValue(SILValue value,
                     bool isAddressCapturedByPartialApply = false) const;
 
+private:
+  TrackableValue
+  getTrackableValueHelper(SILValue value,
+                          bool isAddressCapturedByPartialApply = false) const;
+
+public:
   /// An actor introducing inst is an instruction that doesn't have any
   /// non-Sendable parameters and produces a new value that has to be actor
   /// isolated.
@@ -378,7 +435,8 @@ class RegionAnalysisValueMap {
 
 private:
   std::optional<TrackableValue> getValueForId(Element id) const;
-  std::optional<TrackableValue> tryToTrackValue(SILValue value) const;
+  std::optional<TrackableValueLookupResult>
+  tryToTrackValue(SILValue value) const;
   TrackableValue
   getActorIntroducingRepresentative(SILInstruction *introducingInst,
                                     SILIsolationInfo isolation) const;
@@ -400,6 +458,15 @@ class RegionAnalysisValueMap {
   UnderlyingTrackedValueInfo
   getUnderlyingTrackedValueHelper(SILValue value) const;
 
+  /// A helper function that performs the actual getUnderlyingTrackedValue
+  /// computation that is cached in getUnderlyingTrackedValue(). Please never
+  /// call this directly! Only call it from getUnderlyingTrackedValue.
+  UnderlyingTrackedValueInfo
+  getUnderlyingTrackedValueHelperObject(SILValue value) const;
+
+  UnderlyingTrackedValueInfo
+  getUnderlyingTrackedValueHelperAddress(SILValue value) const;
+
   UnderlyingTrackedValueInfo getUnderlyingTrackedValue(SILValue value) const {
     // Use try_emplace so we only construct underlying tracked value info on
     // success and only lookup once in the hash table.
@@ -477,6 +544,10 @@ class RegionAnalysisFunctionInfo {
 
   bool isSupportedFunction() const { return supportedFunction; }
 
+  NullablePtr<BlockPartitionState> getBlockState(SILBasicBlock *block) const {
+    return blockStates->get(block);
+  }
+
   using iterator = BasicBlockData::iterator;
   using const_iterator = BasicBlockData::const_iterator;
   using reverse_iterator = BasicBlockData::reverse_iterator;
diff --git a/include/swift/SILOptimizer/Differentiation/Common.h b/include/swift/SILOptimizer/Differentiation/Common.h
index d43bf3897cd6c..7ce4b59c45419 100644
--- a/include/swift/SILOptimizer/Differentiation/Common.h
+++ b/include/swift/SILOptimizer/Differentiation/Common.h
@@ -286,7 +286,7 @@ inline void createEntryArguments(SILFunction *f) {
 
 /// Cloner that remaps types using the target function's generic environment.
 class BasicTypeSubstCloner final
-    : public TypeSubstCloner<BasicTypeSubstCloner, SILOptFunctionBuilder> {
+    : public TypeSubstCloner<BasicTypeSubstCloner> {
 
   static SubstitutionMap getSubstitutionMap(SILFunction *target) {
     if (auto *targetGenEnv = target->getGenericEnvironment())
diff --git a/include/swift/SILOptimizer/Differentiation/DifferentiationInvoker.h b/include/swift/SILOptimizer/Differentiation/DifferentiationInvoker.h
index 63b9eb6eb824b..868573914f93b 100644
--- a/include/swift/SILOptimizer/Differentiation/DifferentiationInvoker.h
+++ b/include/swift/SILOptimizer/Differentiation/DifferentiationInvoker.h
@@ -71,10 +71,17 @@ struct DifferentiationInvoker {
 
     /// The parent `apply` instruction and the witness associated with the
     /// `IndirectDifferentiation` case.
-    std::pair<ApplyInst *, SILDifferentiabilityWitness *>
-        indirectDifferentiation;
+    /// Note: This used to be a std::pair, but on FreeBSD, libc++ is
+    /// configured with _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
+    /// and hence does not have a trivial copy constructor
+    struct IndirectDifferentiation {
+      ApplyInst *applyInst;
+      SILDifferentiabilityWitness *witness;
+    };
+    IndirectDifferentiation indirectDifferentiation;
+
     Value(ApplyInst *applyInst, SILDifferentiabilityWitness *witness)
-        : indirectDifferentiation({applyInst, witness}) {}
+      : indirectDifferentiation({applyInst, witness}) {}
 
     /// The witness associated with the `SILDifferentiabilityWitnessInvoker`
     /// case.
@@ -111,7 +118,8 @@ struct DifferentiationInvoker {
   std::pair<ApplyInst *, SILDifferentiabilityWitness *>
   getIndirectDifferentiation() const {
     assert(kind == Kind::IndirectDifferentiation);
-    return value.indirectDifferentiation;
+    return std::make_pair(value.indirectDifferentiation.applyInst,
+                          value.indirectDifferentiation.witness);
   }
 
   SILDifferentiabilityWitness *getSILDifferentiabilityWitnessInvoker() const {
diff --git a/include/swift/SILOptimizer/OptimizerBridging.h b/include/swift/SILOptimizer/OptimizerBridging.h
index 4b42988f936cf..144a9a826eec2 100644
--- a/include/swift/SILOptimizer/OptimizerBridging.h
+++ b/include/swift/SILOptimizer/OptimizerBridging.h
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -13,17 +13,15 @@
 #ifndef SWIFT_SILOPTIMIZER_OPTIMIZERBRIDGING_H
 #define SWIFT_SILOPTIMIZER_OPTIMIZERBRIDGING_H
 
-// Do not add other C++/llvm/swift header files here!
-// Function implementations should be placed into OptimizerBridgingImpl.h or PassManager.cpp
-// (under OptimizerBridging) andrequired header files should be added there.
-//
-// Pure bridging mode does not permit including any C++/llvm/swift headers.
-// See also the comments for `BRIDGING_MODE` in the top-level CMakeLists.txt file.
-//
+/// `OptimizerBridging.h` is imported into Swift. Be *very* careful with what
+/// you include here and keep these includes minimal!
+///
+/// See include guidelines and caveats in `BasicBridging.h`.
 #include "swift/AST/ASTBridging.h"
 #include "swift/SIL/SILBridging.h"
+#include "swift/SILOptimizer/Analysis/ArrayCallKind.h"
 
-#ifndef USED_IN_CPP_SOURCE
+#ifndef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 
 // Pure bridging mode does not permit including any C++/llvm/swift headers.
 // See also the comments for `BRIDGING_MODE` in the top-level CMakeLists.txt file.
@@ -34,26 +32,22 @@
 #error "should not include llvm headers into bridging header"
 #endif
 
-#endif // USED_IN_CPP_SOURCE
+#endif // #ifndef NOT_COMPILED_WITH_SWIFT_PURE_BRIDGING_MODE
 
 SWIFT_BEGIN_NULLABILITY_ANNOTATIONS
 
 namespace swift {
 class AliasAnalysis;
+class ArraySemanticsCall;
 class BasicCalleeAnalysis;
 class CalleeList;
 class DeadEndBlocks;
 class DominanceInfo;
 class PostDominanceInfo;
-class BasicBlockSet;
-class NodeSet;
-class OperandSet;
-class ClonerWithFixedLocation;
+class SILLoopInfo;
+class SILLoop;
 class SwiftPassInvocation;
-class FixedSizeSlabPayload;
-class FixedSizeSlab;
 class SILVTable;
-class ClosureSpecializationCloner;
 }
 
 struct BridgedPassContext;
@@ -68,14 +62,14 @@ struct BridgedAliasAnalysis {
   typedef void (* _Nonnull InitFn)(BridgedAliasAnalysis aliasAnalysis, SwiftInt size);
   typedef void (* _Nonnull DestroyFn)(BridgedAliasAnalysis aliasAnalysis);
   typedef BridgedMemoryBehavior (* _Nonnull GetMemEffectFn)(
-        BridgedPassContext context, BridgedAliasAnalysis aliasAnalysis,
+        BridgedContext context, BridgedAliasAnalysis aliasAnalysis,
         BridgedValue, BridgedInstruction);
   typedef bool (* _Nonnull Escaping2InstFn)(
-        BridgedPassContext context, BridgedAliasAnalysis aliasAnalysis, BridgedValue, BridgedInstruction);
+        BridgedContext context, BridgedAliasAnalysis aliasAnalysis, BridgedValue, BridgedInstruction);
   typedef bool (* _Nonnull Escaping2ValIntFn)(
-        BridgedPassContext context, BridgedAliasAnalysis aliasAnalysis, BridgedValue, BridgedValue);
+        BridgedContext context, BridgedAliasAnalysis aliasAnalysis, BridgedValue, BridgedValue);
   typedef bool (* _Nonnull MayAliasFn)(
-        BridgedPassContext context, BridgedAliasAnalysis aliasAnalysis, BridgedValue, BridgedValue);
+        BridgedContext context, BridgedAliasAnalysis aliasAnalysis, BridgedValue, BridgedValue);
 
   static void registerAnalysis(InitFn initFn,
                                DestroyFn destroyFn,
@@ -120,6 +114,8 @@ struct BridgedDomTree {
   swift::DominanceInfo * _Nonnull di;
 
   BRIDGED_INLINE bool dominates(BridgedBasicBlock dominating, BridgedBasicBlock dominated) const;
+  BRIDGED_INLINE SwiftInt getNumberOfChildren(BridgedBasicBlock bb) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock getChildAt(BridgedBasicBlock bb, SwiftInt index) const;
 };
 
 struct BridgedPostDomTree {
@@ -128,84 +124,23 @@ struct BridgedPostDomTree {
   BRIDGED_INLINE bool postDominates(BridgedBasicBlock dominating, BridgedBasicBlock dominated) const;
 };
 
-struct BridgedUtilities {
-  typedef void (* _Nonnull VerifyFunctionFn)(BridgedPassContext, BridgedFunction);
-  typedef void (* _Nonnull UpdateFunctionFn)(BridgedPassContext, BridgedFunction);
-  typedef void (* _Nonnull UpdatePhisFn)(BridgedPassContext, BridgedArrayRef);
-
-  static void registerVerifier(VerifyFunctionFn verifyFunctionFn);
-  static void registerPhiUpdater(UpdateFunctionFn updateBorrowedFromFn,
-                                 UpdatePhisFn updateBorrowedFromPhisFn,
-                                 UpdatePhisFn replacePhisWithIncomingValuesFn);
-};
-
-struct BridgedBasicBlockSet {
-  swift::BasicBlockSet * _Nonnull set;
-
-  BRIDGED_INLINE bool contains(BridgedBasicBlock block) const;
-  BRIDGED_INLINE bool insert(BridgedBasicBlock block) const;
-  BRIDGED_INLINE void erase(BridgedBasicBlock block) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedFunction getFunction() const;
-};
-
-struct BridgedNodeSet {
-  swift::NodeSet * _Nonnull set;
-
-  BRIDGED_INLINE bool containsValue(BridgedValue value) const;
-  BRIDGED_INLINE bool insertValue(BridgedValue value) const;
-  BRIDGED_INLINE void eraseValue(BridgedValue value) const;
-  BRIDGED_INLINE bool containsInstruction(BridgedInstruction inst) const;
-  BRIDGED_INLINE bool insertInstruction(BridgedInstruction inst) const;
-  BRIDGED_INLINE void eraseInstruction(BridgedInstruction inst) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedFunction getFunction() const;
-};
-
-struct BridgedOperandSet {
-  swift::OperandSet * _Nonnull set;
-
-  BRIDGED_INLINE bool contains(BridgedOperand operand) const;
-  BRIDGED_INLINE bool insert(BridgedOperand operand) const;
-  BRIDGED_INLINE void erase(BridgedOperand operand) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedFunction getFunction() const;
-};
-
-struct BridgedCloner {
-  swift::ClonerWithFixedLocation * _Nonnull cloner;
-
-  BridgedCloner(BridgedGlobalVar var, BridgedPassContext context);
-  BridgedCloner(BridgedInstruction inst, BridgedPassContext context);
-  void destroy(BridgedPassContext context);
-  SWIFT_IMPORT_UNSAFE BridgedValue getClonedValue(BridgedValue v);
-  bool isValueCloned(BridgedValue v) const;
-  void clone(BridgedInstruction inst);
-  void recordFoldedValue(BridgedValue origValue, BridgedValue mappedValue);
-};
-
-struct BridgedSpecializationCloner {
-  swift::ClosureSpecializationCloner * _Nonnull closureSpecCloner;
-
-  SWIFT_IMPORT_UNSAFE BridgedSpecializationCloner(BridgedFunction emptySpecializedFunction);
-  SWIFT_IMPORT_UNSAFE BridgedFunction getCloned() const;
-  SWIFT_IMPORT_UNSAFE BridgedBasicBlock getClonedBasicBlock(BridgedBasicBlock originalBasicBlock) const;
-  void cloneFunctionBody(BridgedFunction originalFunction, BridgedBasicBlock clonedEntryBlock, BridgedValueArray clonedEntryBlockArgs) const;
+struct BridgedLoopTree {
+  swift::SILLoopInfo * _Nonnull li;
+  
+  BRIDGED_INLINE SwiftInt getTopLevelLoopCount() const;
+  BRIDGED_INLINE BridgedLoop getLoop(SwiftInt index) const;
+  
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock splitEdge(BridgedBasicBlock bb, SwiftInt edgeIndex, BridgedDomTree domTree) const;
 };
 
 struct BridgedPassContext {
   swift::SwiftPassInvocation * _Nonnull invocation;
 
-  enum class SILStage {
-    Raw,
-    Canonical,
-    Lowered
-  };
+  BridgedPassContext(swift::SwiftPassInvocation * _Nonnull invocation) : invocation(invocation) {}
+  BRIDGED_INLINE BridgedPassContext(BridgedContext ctxt);
 
-  BridgedOwnedString getModuleDescription() const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedChangeNotificationHandler asNotificationHandler() const;
-  BRIDGED_INLINE void notifyDependencyOnBodyOf(BridgedFunction otherFunction) const;
-  BRIDGED_INLINE SILStage getSILStage() const;
   BRIDGED_INLINE bool hadError() const;
-  BRIDGED_INLINE bool moduleIsSerialized() const;
-  BRIDGED_INLINE bool isTransforming(BridgedFunction function) const;
+  BRIDGED_INLINE void notifyDependencyOnBodyOf(BridgedFunction otherFunction) const;
 
   // Analysis
 
@@ -215,6 +150,15 @@ struct BridgedPassContext {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDomTree getDomTree() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedPostDomTree getPostDomTree() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj getSwiftArrayDecl() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj getSwiftMutableSpanDecl() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedLoopTree getLoopTree() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedLoop getLoop() const;
+  
+  // Array semantics call
+  
+  static BRIDGED_INLINE ArrayCallKind getArraySemanticsCallKind(BridgedInstruction inst);
+  BRIDGED_INLINE bool canHoistArraySemanticsCall(BridgedInstruction inst, BridgedInstruction toInst) const;
+  BRIDGED_INLINE void hoistArraySemanticsCall(BridgedInstruction inst, BridgedInstruction beforeInst) const;
 
   // AST
 
@@ -228,38 +172,38 @@ struct BridgedPassContext {
     bool cfgChanged;
   };
 
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock splitBlockBefore(BridgedInstruction bridgedInst) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock splitBlockAfter(BridgedInstruction bridgedInst) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock createBlockAfter(BridgedBasicBlock bridgedBlock) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock appendBlock(BridgedFunction bridgedFunction) const;
-  BRIDGED_INLINE void eraseInstruction(BridgedInstruction inst) const;
-  BRIDGED_INLINE void eraseBlock(BridgedBasicBlock block) const;
-  static BRIDGED_INLINE void moveInstructionBefore(BridgedInstruction inst, BridgedInstruction beforeInst);
   bool tryOptimizeApplyOfPartialApply(BridgedInstruction closure) const;
   bool tryDeleteDeadClosure(BridgedInstruction closure, bool needKeepArgsAlive) const;
   SWIFT_IMPORT_UNSAFE DevirtResult tryDevirtualizeApply(BridgedInstruction apply, bool isMandatory) const;
   bool tryOptimizeKeypath(BridgedInstruction apply) const;
   SWIFT_IMPORT_UNSAFE OptionalBridgedValue constantFoldBuiltin(BridgedInstruction builtin) const;
   SWIFT_IMPORT_UNSAFE OptionalBridgedFunction specializeFunction(BridgedFunction function,
-                                                                 BridgedSubstitutionMap substitutions) const;
+                                                                 BridgedSubstitutionMap substitutions,
+                                                                 bool convertIndirectToDirect,
+                                                                 bool isMandatory) const;
   void deserializeAllCallees(BridgedFunction function, bool deserializeAll) const;
   bool specializeClassMethodInst(BridgedInstruction cm) const;
   bool specializeWitnessMethodInst(BridgedInstruction wm) const;
   bool specializeAppliesInFunction(BridgedFunction function, bool isMandatory) const;
   BridgedOwnedString mangleOutlinedVariable(BridgedFunction function) const;
   BridgedOwnedString mangleAsyncRemoved(BridgedFunction function) const;
-  BridgedOwnedString mangleWithDeadArgs(const SwiftInt * _Nullable deadArgs,
-                                                            SwiftInt numDeadArgs,
-                                                            BridgedFunction function) const;
-  BridgedOwnedString mangleWithClosureArgs(BridgedValueArray closureArgs,
-                                                               BridgedArrayRef closureArgIndices,
-                                                               BridgedFunction applySiteCallee) const;
-
-  SWIFT_IMPORT_UNSAFE BridgedGlobalVar createGlobalVariable(BridgedStringRef name, BridgedType type,
-                                                            BridgedLinkage linkage, bool isLet) const;
+
+  struct ClosureArgMangling {
+    SwiftInt argIdx;
+    OptionalBridgedInstruction inst;
+    SwiftInt otherArgIdx;
+  };
+
+  BridgedOwnedString mangleWithDeadArgs(BridgedArrayRef bridgedDeadArgIndices, BridgedFunction function) const;
+  BridgedOwnedString mangleWithClosureArgs(BridgedArrayRef closureArgManglings, BridgedFunction applySiteCallee) const;
+  BridgedOwnedString mangleWithConstCaptureArgs(BridgedArrayRef bridgedConstArgs,
+                                                BridgedFunction applySiteCallee) const;
+  BridgedOwnedString mangleWithBoxToStackPromotedArgs(BridgedArrayRef bridgedPromotedArgIndices,
+                                                      BridgedFunction bridgedOriginalFunction) const;
+
   void inlineFunction(BridgedInstruction apply, bool mandatoryInline) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedValue getSILUndef(BridgedType type) const;
   BRIDGED_INLINE bool eliminateDeadAllocations(BridgedFunction f) const;
+  void eraseFunction(BridgedFunction function) const;
 
   BRIDGED_INLINE bool shouldExpand(BridgedType type) const;
 
@@ -270,36 +214,12 @@ struct BridgedPassContext {
   SwiftInt getStaticStride(BridgedType type) const;
   bool canMakeStaticObjectReadOnly(BridgedType type) const;
 
-  // Sets
-
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlockSet allocBasicBlockSet() const;
-  BRIDGED_INLINE void freeBasicBlockSet(BridgedBasicBlockSet set) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedNodeSet allocNodeSet() const;
-  BRIDGED_INLINE void freeNodeSet(BridgedNodeSet set) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedOperandSet allocOperandSet() const;
-  BRIDGED_INLINE void freeOperandSet(BridgedOperandSet set) const;
-
   // Stack nesting
 
   BRIDGED_INLINE void notifyInvalidatedStackNesting() const;
   BRIDGED_INLINE bool getNeedFixStackNesting() const;
   void fixStackNesting(BridgedFunction function) const;
 
-  // Slabs
-
-  struct Slab {
-    swift::FixedSizeSlabPayload * _Nullable data = nullptr;
-
-    BRIDGED_INLINE static SwiftInt getCapacity();
-    BRIDGED_INLINE Slab(swift::FixedSizeSlab * _Nullable slab);
-    BRIDGED_INLINE swift::FixedSizeSlab * _Nullable getSlab() const;
-    SWIFT_IMPORT_UNSAFE BRIDGED_INLINE Slab getNext() const;
-    SWIFT_IMPORT_UNSAFE BRIDGED_INLINE Slab getPrevious() const;
-  };
-
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE Slab allocSlab(Slab afterSlab) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE Slab freeSlab(Slab slab) const;
-
   // Access SIL module data structures
 
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedFunction getFirstFunctionInModule() const;
@@ -314,59 +234,16 @@ struct BridgedPassContext {
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDefaultWitnessTable getFirstDefaultWitnessTableInModule() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE static OptionalBridgedDefaultWitnessTable getNextDefaultWitnessTableInModule(
                                                                                   BridgedDefaultWitnessTable table);
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedFunction lookupFunction(BridgedStringRef name) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedFunction loadFunction(BridgedStringRef name,
-                                                                          bool loadCalleesRecursively) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
-  OptionalBridgedVTable lookupVTable(BridgedDeclObj classDecl) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
-  OptionalBridgedVTable lookupSpecializedVTable(BridgedType classType) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
-  BridgedConformance getSpecializedConformance(BridgedConformance genericConformance,
-                                                       BridgedASTType type,
-                                                       BridgedSubstitutionMap substitutions) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
-  OptionalBridgedWitnessTable lookupWitnessTable(BridgedConformance conformance) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedWitnessTable createWitnessTable(BridgedLinkage linkage,
-                                                                            bool serialized,
-                                                                            BridgedConformance conformance,
-                                                                            BridgedArrayRef bridgedEntries) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedVTable createSpecializedVTable(BridgedType classType,
-                                                                           bool serialized,
-                                                                           BridgedArrayRef bridgedEntries) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE void loadFunction(BridgedFunction function, bool loadCalleesRecursively) const;
-  SWIFT_IMPORT_UNSAFE OptionalBridgedFunction lookupStdlibFunction(BridgedStringRef name) const;
-  SWIFT_IMPORT_UNSAFE OptionalBridgedFunction lookUpNominalDeinitFunction(BridgedDeclObj nominal) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedSubstitutionMap getContextSubstitutionMap(BridgedType type) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getBuiltinIntegerType(SwiftInt bitWidth) const;
-  BRIDGED_INLINE bool calleesAreStaticallyKnowable(BridgedDeclRef method) const;
-  SWIFT_IMPORT_UNSAFE BridgedFunction createEmptyFunction(BridgedStringRef name,
-                                                          const BridgedParameterInfo * _Nullable bridgedParams,
-                                                          SwiftInt paramCount,
-                                                          bool hasSelfParam,
-                                                          BridgedFunction fromFunc) const;
-  void moveFunctionBody(BridgedFunction sourceFunc, BridgedFunction destFunc) const;
 
   // Passmanager housekeeping
 
-  BRIDGED_INLINE void beginTransformFunction(BridgedFunction function) const;
-  BRIDGED_INLINE void endTransformFunction() const;
   BRIDGED_INLINE bool continueWithNextSubpassRun(OptionalBridgedInstruction inst) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedPassContext initializeNestedPassContext(BridgedFunction newFunction) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedContext initializeNestedPassContext(BridgedFunction newFunction) const;
   BRIDGED_INLINE void deinitializedNestedPassContext() const;
   BRIDGED_INLINE void
   addFunctionToPassManagerWorklist(BridgedFunction newFunction,
                                    BridgedFunction oldFunction) const;
 
-  // SSAUpdater
-
-  BRIDGED_INLINE void
-  SSAUpdater_initialize(BridgedFunction function, BridgedType type,
-                        BridgedValue::Ownership ownership) const;
-  BRIDGED_INLINE void SSAUpdater_addAvailableValue(BridgedBasicBlock block, BridgedValue value) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedValue SSAUpdater_getValueAtEndOfBlock(BridgedBasicBlock block) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedValue SSAUpdater_getValueInMiddleOfBlock(BridgedBasicBlock block) const;
-
   // Options
 
   enum class AssertConfiguration {
@@ -382,18 +259,20 @@ struct BridgedPassContext {
   BRIDGED_INLINE bool enableMoveInoutStackProtection() const;
   BRIDGED_INLINE AssertConfiguration getAssertConfiguration() const;
   bool enableSimplificationFor(BridgedInstruction inst) const;
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj getCurrentModuleContext() const;
   BRIDGED_INLINE bool enableWMORequiredDiagnostics() const;
+  BRIDGED_INLINE bool noAllocations() const;
 
   // Temporary for AddressableParameters Bootstrapping.
   BRIDGED_INLINE bool enableAddressDependencies() const;
 
   // Closure specializer
-  SWIFT_IMPORT_UNSAFE BridgedFunction ClosureSpecializer_createEmptyFunctionWithSpecializedSignature(BridgedStringRef specializedName,
+  SWIFT_IMPORT_UNSAFE BridgedFunction createSpecializedFunctionDeclaration(BridgedStringRef specializedName,
                                                         const BridgedParameterInfo * _Nullable specializedBridgedParams,
                                                         SwiftInt paramCount,
-                                                        BridgedFunction bridgedApplySiteCallee,
-                                                        bool isSerialized) const;
+                                                        BridgedFunction bridgedOriginal,
+                                                        bool makeThin,
+                                                        bool makeBare,
+                                                        bool preserveGenericSignature) const;
 
   bool completeLifetime(BridgedValue value) const;
 };
@@ -412,23 +291,21 @@ BridgedDynamicCastResult classifyDynamicCastBridged(BridgedCanType sourceTy, Bri
 
 BridgedDynamicCastResult classifyDynamicCastBridged(BridgedInstruction inst);
 
-void verifierError(BridgedStringRef message, OptionalBridgedInstruction atInstruction, OptionalBridgedArgument atArgument);
-
 //===----------------------------------------------------------------------===//
 //                          Pass registration
 //===----------------------------------------------------------------------===//
 
 struct BridgedFunctionPassCtxt {
   BridgedFunction function;
-  BridgedPassContext passContext;
+  BridgedContext passContext;
 } ;
 
 struct BridgedInstructionPassCtxt {
   BridgedInstruction instruction;
-  BridgedPassContext passContext;
+  BridgedContext passContext;
 };
 
-typedef void (* _Nonnull BridgedModulePassRunFn)(BridgedPassContext);
+typedef void (* _Nonnull BridgedModulePassRunFn)(BridgedContext);
 typedef void (* _Nonnull BridgedFunctionPassRunFn)(BridgedFunctionPassCtxt);
 typedef void (* _Nonnull BridgedInstructionPassRunFn)(BridgedInstructionPassCtxt);
 
@@ -439,6 +316,9 @@ void SILPassManager_registerFunctionPass(BridgedStringRef name,
 void SILCombine_registerInstructionPass(BridgedStringRef instClassName,
                                         BridgedInstructionPassRunFn runFn);
 
+void registerFunctionTestThunk(SwiftNativeFunctionTestThunk);
+void registerFunctionTest(BridgedStringRef, void *_Nonnull nativeSwiftContext);
+
 #ifndef PURE_BRIDGING_MODE
 // In _not_ PURE_BRIDGING_MODE, briding functions are inlined and therefore inluded in the header file.
 #include "OptimizerBridgingImpl.h"
diff --git a/include/swift/SILOptimizer/OptimizerBridgingImpl.h b/include/swift/SILOptimizer/OptimizerBridgingImpl.h
index b31b2078727da..f700122cd64cd 100644
--- a/include/swift/SILOptimizer/OptimizerBridgingImpl.h
+++ b/include/swift/SILOptimizer/OptimizerBridgingImpl.h
@@ -21,12 +21,16 @@
 
 #include "swift/Demangling/Demangle.h"
 #include "swift/SILOptimizer/Analysis/AliasAnalysis.h"
+#include "swift/SILOptimizer/Analysis/ArraySemantic.h"
 #include "swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h"
 #include "swift/SILOptimizer/Analysis/DeadEndBlocksAnalysis.h"
 #include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
+#include "swift/SILOptimizer/Analysis/LoopAnalysis.h"
 #include "swift/SILOptimizer/OptimizerBridging.h"
 #include "swift/SILOptimizer/PassManager/PassManager.h"
+#include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/InstOptUtils.h"
+#include "swift/SILOptimizer/Utils/DebugOptUtils.h"
 
 SWIFT_BEGIN_NULLABILITY_ANNOTATIONS
 
@@ -81,89 +85,77 @@ bool BridgedDomTree::dominates(BridgedBasicBlock dominating, BridgedBasicBlock d
   return di->dominates(dominating.unbridged(), dominated.unbridged());
 }
 
-bool BridgedPostDomTree::postDominates(BridgedBasicBlock dominating, BridgedBasicBlock dominated) const {
-  return pdi->dominates(dominating.unbridged(), dominated.unbridged());
-}
-
-//===----------------------------------------------------------------------===//
-//                            BridgedBasicBlockSet
-//===----------------------------------------------------------------------===//
-
-bool BridgedBasicBlockSet::contains(BridgedBasicBlock block) const {
-  return set->contains(block.unbridged());
-}
-
-bool BridgedBasicBlockSet::insert(BridgedBasicBlock block) const {
-  return set->insert(block.unbridged());
+SwiftInt BridgedDomTree::getNumberOfChildren(BridgedBasicBlock bb) const {
+  return di->getNode(bb.unbridged())->getNumChildren();
 }
 
-void BridgedBasicBlockSet::erase(BridgedBasicBlock block) const {
-  set->erase(block.unbridged());
+BridgedBasicBlock BridgedDomTree::getChildAt(BridgedBasicBlock bb, SwiftInt index) const {
+  return {di->getNode(bb.unbridged())->begin()[index]->getBlock()};
 }
 
-BridgedFunction BridgedBasicBlockSet::getFunction() const {
-  return {set->getFunction()};
+bool BridgedPostDomTree::postDominates(BridgedBasicBlock dominating, BridgedBasicBlock dominated) const {
+  return pdi->dominates(dominating.unbridged(), dominated.unbridged());
 }
 
 //===----------------------------------------------------------------------===//
-//                            BridgedNodeSet
+//                         BridgedLoopTree, BridgedLoop
 //===----------------------------------------------------------------------===//
 
-bool BridgedNodeSet::containsValue(BridgedValue value) const {
-  return set->contains(value.getSILValue());
-}
-
-bool BridgedNodeSet::insertValue(BridgedValue value) const {
-  return set->insert(value.getSILValue());
+SwiftInt BridgedLoopTree::getTopLevelLoopCount() const {
+  return li->end() - li->begin();
 }
 
-void BridgedNodeSet::eraseValue(BridgedValue value) const {
-  set->erase(value.getSILValue());
+BridgedLoop BridgedLoopTree::getLoop(SwiftInt index) const {
+  return {li->begin()[index]};
 }
 
-bool BridgedNodeSet::containsInstruction(BridgedInstruction inst) const {
-  return set->contains(inst.unbridged()->asSILNode());
+BridgedBasicBlock BridgedLoopTree::splitEdge(BridgedBasicBlock bb, SwiftInt edgeIndex, BridgedDomTree domTree) const {
+  return {swift::splitEdge(bb.unbridged()->getTerminator(), edgeIndex, domTree.di, li)};
 }
 
-bool BridgedNodeSet::insertInstruction(BridgedInstruction inst) const {
-  return set->insert(inst.unbridged()->asSILNode());
+SwiftInt BridgedLoop::getInnerLoopCount() const {
+  return l->end() - l->begin();
 }
 
-void BridgedNodeSet::eraseInstruction(BridgedInstruction inst) const {
-  set->erase(inst.unbridged()->asSILNode());
+BridgedLoop BridgedLoop::getInnerLoop(SwiftInt index) const {
+  return {l->begin()[index]};
 }
 
-BridgedFunction BridgedNodeSet::getFunction() const {
-  return {set->getFunction()};
+SwiftInt BridgedLoop::getBasicBlockCount() const {
+  return l->getBlocks().size();
 }
 
-//===----------------------------------------------------------------------===//
-//                            BridgedOperandSet
-//===----------------------------------------------------------------------===//
-
-bool BridgedOperandSet::contains(BridgedOperand operand) const {
-  return set->contains(operand.op);
+BridgedBasicBlock BridgedLoop::getBasicBlock(SwiftInt index) const {
+  return {l->getBlocks()[index]};
 }
 
-bool BridgedOperandSet::insert(BridgedOperand operand) const {
-  return set->insert(operand.op);
+OptionalBridgedBasicBlock BridgedLoop::getPreheader() const {
+  return {l->getLoopPreheader()};
 }
 
-void BridgedOperandSet::erase(BridgedOperand operand) const {
-  set->erase(operand.op);
+BridgedBasicBlock BridgedLoop::getHeader() const {
+  return {l->getHeader()};
 }
 
-BridgedFunction BridgedOperandSet::getFunction() const {
-  return {set->getFunction()};
+bool BridgedLoop::contains(BridgedBasicBlock block) const {
+  return l->contains(block.unbridged());
 }
 
 //===----------------------------------------------------------------------===//
 //                            BridgedPassContext
 //===----------------------------------------------------------------------===//
 
-BridgedChangeNotificationHandler BridgedPassContext::asNotificationHandler() const {
-  return {invocation};
-}
+static_assert((int)swift::SILAnalysis::InvalidationKind::Instructions ==
+              (int)swift::SILContext::NotificationKind::Instructions);
+static_assert((int)swift::SILAnalysis::InvalidationKind::Calls ==
+              (int)swift::SILContext::NotificationKind::Calls);
+static_assert((int)swift::SILAnalysis::InvalidationKind::Branches ==
+              (int)swift::SILContext::NotificationKind::Branches);
+static_assert((int)swift::SILAnalysis::InvalidationKind::Effects ==
+              (int)swift::SILContext::NotificationKind::Effects);
+
+BridgedPassContext::BridgedPassContext(BridgedContext ctxt) :
+  invocation(static_cast<swift::SwiftPassInvocation *>(ctxt.context)) {}
 
 void BridgedPassContext::notifyDependencyOnBodyOf(BridgedFunction otherFunction) const {
   // Currently `otherFunction` is ignored. We could design a more accurate dependency system
@@ -171,22 +163,10 @@ void BridgedPassContext::notifyDependencyOnBodyOf(BridgedFunction otherFunction)
   invocation->getPassManager()->setDependingOnCalleeBodies();
 }
 
-BridgedPassContext::SILStage BridgedPassContext::getSILStage() const {
-  return (SILStage)invocation->getPassManager()->getModule()->getStage();
-}
-
 bool BridgedPassContext::hadError() const {
   return invocation->getPassManager()->getModule()->getASTContext().hadError();
 }
 
-bool BridgedPassContext::moduleIsSerialized() const {
-  return invocation->getPassManager()->getModule()->isSerialized();
-}
-
-bool BridgedPassContext::isTransforming(BridgedFunction function) const {
-  return invocation->getFunction() == function.getFunction();
-}
-
 BridgedAliasAnalysis BridgedPassContext::getAliasAnalysis() const {
   return {invocation->getPassManager()->getAnalysis<swift::AliasAnalysis>(invocation->getFunction())};
 }
@@ -210,126 +190,53 @@ BridgedPostDomTree BridgedPassContext::getPostDomTree() const {
   return {pda->get(invocation->getFunction())};
 }
 
+BridgedLoopTree BridgedPassContext::getLoopTree() const {
+  auto *lt = invocation->getPassManager()->getAnalysis<swift::SILLoopAnalysis>();
+  return {lt->get(invocation->getFunction())};
+}
+
 BridgedDeclObj BridgedPassContext::getSwiftArrayDecl() const {
   swift::SILModule *mod = invocation->getPassManager()->getModule();
   return {mod->getASTContext().getArrayDecl()};
 }
 
-// AST
-
-SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
-BridgedDiagnosticEngine BridgedPassContext::getDiagnosticEngine() const {
+BridgedDeclObj BridgedPassContext::getSwiftMutableSpanDecl() const {
   swift::SILModule *mod = invocation->getPassManager()->getModule();
-  return {&mod->getASTContext().Diags};
-}
-
-// SIL modifications
-
-BridgedBasicBlock BridgedPassContext::splitBlockBefore(BridgedInstruction bridgedInst) const {
-  auto *block = bridgedInst.unbridged()->getParent();
-  return {block->split(bridgedInst.unbridged()->getIterator())};
+  return {mod->getASTContext().getMutableSpanDecl()};
 }
 
-BridgedBasicBlock BridgedPassContext::splitBlockAfter(BridgedInstruction bridgedInst) const {
-  auto *block = bridgedInst.unbridged()->getParent();
-  return {block->split(std::next(bridgedInst.unbridged()->getIterator()))};
-}
+// Array semantics call
 
-BridgedBasicBlock BridgedPassContext::createBlockAfter(BridgedBasicBlock bridgedBlock) const {
-  swift::SILBasicBlock *block = bridgedBlock.unbridged();
-  return {block->getParent()->createBasicBlockAfter(block)};
+ArrayCallKind BridgedPassContext::getArraySemanticsCallKind(BridgedInstruction inst) {
+  swift::ArraySemanticsCall semCall(inst.unbridged());
+  return semCall.getKind();
 }
 
-BridgedBasicBlock BridgedPassContext::appendBlock(BridgedFunction bridgedFunction) const {
-  return {bridgedFunction.getFunction()->createBasicBlock()};
+bool BridgedPassContext::canHoistArraySemanticsCall(BridgedInstruction inst, BridgedInstruction toInst) const {
+  swift::ArraySemanticsCall semCall(inst.unbridged());
+  return semCall.canHoist(toInst.unbridged(), getDomTree().di);
 }
 
-void BridgedPassContext::eraseInstruction(BridgedInstruction inst) const {
-  invocation->eraseInstruction(inst.unbridged());
+void BridgedPassContext::hoistArraySemanticsCall(BridgedInstruction inst, BridgedInstruction beforeInst) const {
+  swift::ArraySemanticsCall semCall(inst.unbridged());
+  semCall.hoist(beforeInst.unbridged(), getDomTree().di);
 }
 
-void BridgedPassContext::eraseBlock(BridgedBasicBlock block) const {
-  block.unbridged()->eraseFromParent();
-}
+// AST
 
-void BridgedPassContext::moveInstructionBefore(BridgedInstruction inst, BridgedInstruction beforeInst) {
-  swift::SILBasicBlock::moveInstruction(inst.unbridged(), beforeInst.unbridged());
+SWIFT_IMPORT_UNSAFE BRIDGED_INLINE
+BridgedDiagnosticEngine BridgedPassContext::getDiagnosticEngine() const {
+  swift::SILModule *mod = invocation->getPassManager()->getModule();
+  return {&mod->getASTContext().Diags};
 }
 
-BridgedValue BridgedPassContext::getSILUndef(BridgedType type) const {
-  return {swift::SILUndef::get(invocation->getFunction(), type.unbridged())};
-}
+// SIL modifications
 
 bool BridgedPassContext::eliminateDeadAllocations(BridgedFunction f) const {
   return swift::eliminateDeadAllocations(f.getFunction(),
                                          this->getDomTree().di);
 }
 
-BridgedBasicBlockSet BridgedPassContext::allocBasicBlockSet() const {
-  return {invocation->allocBlockSet()};
-}
-
-void BridgedPassContext::freeBasicBlockSet(BridgedBasicBlockSet set) const {
-  invocation->freeBlockSet(set.set);
-}
-
-BridgedNodeSet BridgedPassContext::allocNodeSet() const {
-  return {invocation->allocNodeSet()};
-}
-
-void BridgedPassContext::freeNodeSet(BridgedNodeSet set) const {
-  invocation->freeNodeSet(set.set);
-}
-
-BridgedOperandSet BridgedPassContext::allocOperandSet() const {
-  return {invocation->allocOperandSet()};
-}
-
-void BridgedPassContext::freeOperandSet(BridgedOperandSet set) const {
-  invocation->freeOperandSet(set.set);
-}
-
-void BridgedPassContext::notifyInvalidatedStackNesting() const {
-  invocation->setNeedFixStackNesting(true);
-}
-
-bool BridgedPassContext::getNeedFixStackNesting() const {
-  return invocation->getNeedFixStackNesting();
-}
-
-SwiftInt BridgedPassContext::Slab::getCapacity() {
-  return (SwiftInt)swift::FixedSizeSlabPayload::capacity;
-}
-
-BridgedPassContext::Slab::Slab(swift::FixedSizeSlab * _Nullable slab) {
-  if (slab) {
-    data = slab;
-    assert((void *)data == slab->dataFor<void>());
-  }
-}
-
-swift::FixedSizeSlab * _Nullable BridgedPassContext::Slab::getSlab() const {
-  if (data)
-    return static_cast<swift::FixedSizeSlab *>(data);
-  return nullptr;
-}
-
-BridgedPassContext::Slab BridgedPassContext::Slab::getNext() const {
-  return &*std::next(getSlab()->getIterator());
-}
-
-BridgedPassContext::Slab BridgedPassContext::Slab::getPrevious() const {
-  return &*std::prev(getSlab()->getIterator());
-}
-
-BridgedPassContext::Slab BridgedPassContext::allocSlab(Slab afterSlab) const {
-  return invocation->allocSlab(afterSlab.getSlab());
-}
-
-BridgedPassContext::Slab BridgedPassContext::freeSlab(Slab slab) const {
-  return invocation->freeSlab(slab.getSlab());
-}
-
 OptionalBridgedFunction BridgedPassContext::getFirstFunctionInModule() const {
   swift::SILModule *mod = invocation->getPassManager()->getModule();
   if (mod->getFunctions().empty())
@@ -399,106 +306,12 @@ getNextDefaultWitnessTableInModule(BridgedDefaultWitnessTable table) {
   return {&*nextIter};
 }
 
-OptionalBridgedFunction BridgedPassContext::lookupFunction(BridgedStringRef name) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  return {mod->lookUpFunction(name.unbridged())};
-}
-
-OptionalBridgedFunction BridgedPassContext::loadFunction(BridgedStringRef name, bool loadCalleesRecursively) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  return {mod->loadFunction(name.unbridged(),
-                            loadCalleesRecursively
-                                ? swift::SILModule::LinkingMode::LinkAll
-                                : swift::SILModule::LinkingMode::LinkNormal)};
-}
-
-OptionalBridgedVTable BridgedPassContext::lookupVTable(BridgedDeclObj classDecl) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  return {mod->lookUpVTable(classDecl.getAs<swift::ClassDecl>())};
-}
-
-OptionalBridgedVTable BridgedPassContext::lookupSpecializedVTable(BridgedType classType) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  return {mod->lookUpSpecializedVTable(classType.unbridged())};
-}
-
-BridgedConformance BridgedPassContext::getSpecializedConformance(
-                                                     BridgedConformance genericConformance,
-                                                     BridgedASTType type,
-                                                     BridgedSubstitutionMap substitutions) const {
-  auto &ctxt = invocation->getPassManager()->getModule()->getASTContext();
-  auto *genConf = llvm::cast<swift::NormalProtocolConformance>(genericConformance.unbridged().getConcrete());
-  auto *c = ctxt.getSpecializedConformance(type.unbridged(), genConf, substitutions.unbridged());
-  return swift::ProtocolConformanceRef(c);
-}
-
-OptionalBridgedWitnessTable BridgedPassContext::lookupWitnessTable(BridgedConformance conformance) const {
-  swift::ProtocolConformanceRef ref = conformance.unbridged();
-  if (!ref.isConcrete()) {
-    return {nullptr};
-  }
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  return {mod->lookUpWitnessTable(ref.getConcrete())};
-}
-
-BridgedWitnessTable BridgedPassContext::createWitnessTable(BridgedLinkage linkage,
-                                                           bool serialized,
-                                                           BridgedConformance conformance,
-                                                           BridgedArrayRef bridgedEntries) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  llvm::SmallVector<swift::SILWitnessTable::Entry, 8> entries;
-  for (const BridgedWitnessTableEntry &e : bridgedEntries.unbridged<BridgedWitnessTableEntry>()) {
-    entries.push_back(e.unbridged());
-  }
-  return {swift::SILWitnessTable::create(*mod, (swift::SILLinkage)linkage,
-                                         serialized ? swift::IsSerialized : swift::IsNotSerialized,
-                                         conformance.unbridged().getConcrete(),
-                                         entries, {})};
-}
-
-BridgedVTable BridgedPassContext::createSpecializedVTable(BridgedType classType,
-                                                          bool serialized,
-                                                          BridgedArrayRef bridgedEntries) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  llvm::SmallVector<swift::SILVTableEntry, 8> entries;
-  for (const BridgedVTableEntry &e : bridgedEntries.unbridged<BridgedVTableEntry>()) {
-    entries.push_back(e.unbridged());
-  }
-  swift::SILType classTy = classType.unbridged();
-  return {swift::SILVTable::create(*mod,
-                                   classTy.getClassOrBoundGenericClass(), classTy,
-                                   serialized ? swift::IsSerialized : swift::IsNotSerialized,
-                                   entries)};
-}
-
-void BridgedPassContext::loadFunction(BridgedFunction function, bool loadCalleesRecursively) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  mod->loadFunction(function.getFunction(),
-                    loadCalleesRecursively ? swift::SILModule::LinkingMode::LinkAll
-                                           : swift::SILModule::LinkingMode::LinkNormal);
-}
-
-BridgedSubstitutionMap BridgedPassContext::getContextSubstitutionMap(BridgedType type) const {
-  swift::SILType ty = type.unbridged();
-  return ty.getASTType()->getContextSubstitutionMap();
-}
-
-BridgedType BridgedPassContext::getBuiltinIntegerType(SwiftInt bitWidth) const {
-  auto &ctxt = invocation->getPassManager()->getModule()->getASTContext();
-  return swift::SILType::getBuiltinIntegerType(bitWidth, ctxt);
-}
-
-bool BridgedPassContext::calleesAreStaticallyKnowable(BridgedDeclRef method) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  return swift::calleesAreStaticallyKnowable(*mod, method.unbridged());
-}
-
-void BridgedPassContext::beginTransformFunction(BridgedFunction function) const {
-  invocation->beginTransformFunction(function.getFunction());
+void BridgedPassContext::notifyInvalidatedStackNesting() const {
+  invocation->setNeedFixStackNesting(true);
 }
 
-void BridgedPassContext::endTransformFunction() const {
-  invocation->endTransformFunction();
+bool BridgedPassContext::getNeedFixStackNesting() const {
+  return invocation->getNeedFixStackNesting();
 }
 
 bool BridgedPassContext::continueWithNextSubpassRun(OptionalBridgedInstruction inst) const {
@@ -507,40 +320,20 @@ bool BridgedPassContext::continueWithNextSubpassRun(OptionalBridgedInstruction i
       inst.unbridged(), invocation->getFunction(), invocation->getTransform());
 }
 
-BridgedPassContext BridgedPassContext::initializeNestedPassContext(BridgedFunction newFunction) const {
-  return { invocation->initializeNestedSwiftPassInvocation(newFunction.getFunction()) }; 
+BridgedContext BridgedPassContext::initializeNestedPassContext(BridgedFunction newFunction) const {
+  return { invocation->initializeNestedSwiftPassInvocation(newFunction.getFunction()) };
 }
 
 void BridgedPassContext::deinitializedNestedPassContext() const {
   invocation->deinitializeNestedSwiftPassInvocation();
 }
 
-void BridgedPassContext::SSAUpdater_initialize(
-    BridgedFunction function, BridgedType type,
-    BridgedValue::Ownership ownership) const {
-  invocation->initializeSSAUpdater(function.getFunction(), type.unbridged(),
-                                   BridgedValue::unbridge(ownership));
-}
-
 void BridgedPassContext::addFunctionToPassManagerWorklist(
     BridgedFunction newFunction, BridgedFunction oldFunction) const {
   swift::SILPassManager *pm = invocation->getPassManager();
-  pm->addFunctionToWorklist(newFunction.getFunction(),
-                            oldFunction.getFunction());
-}
-
-void BridgedPassContext::SSAUpdater_addAvailableValue(BridgedBasicBlock block, BridgedValue value) const {
-  invocation->getSSAUpdater()->addAvailableValue(block.unbridged(),
-                                                 value.getSILValue());
-}
-
-BridgedValue BridgedPassContext::SSAUpdater_getValueAtEndOfBlock(BridgedBasicBlock block) const {
-  return {invocation->getSSAUpdater()->getValueAtEndOfBlock(block.unbridged())};
-}
-
-BridgedValue BridgedPassContext::SSAUpdater_getValueInMiddleOfBlock(BridgedBasicBlock block) const {
-  return {
-      invocation->getSSAUpdater()->getValueInMiddleOfBlock(block.unbridged())};
+  if (llvm::isa<swift::SILFunctionTransform>(invocation->getTransform())) {
+    pm->addFunctionToWorklist(newFunction.getFunction(), oldFunction.getFunction());
+  }
 }
 
 bool BridgedPassContext::enableStackProtection() const {
@@ -555,7 +348,7 @@ bool BridgedPassContext::enableMergeableTraps() const {
 
 bool BridgedPassContext::hasFeature(BridgedFeature feature) const {
   swift::SILModule *mod = invocation->getPassManager()->getModule();
-  return mod->getASTContext().LangOpts.hasFeature((swift::Feature)feature);
+  return mod->getASTContext().LangOpts.hasFeature(swift::Feature(feature));
 }
 
 bool BridgedPassContext::enableMoveInoutStackProtection() const {
@@ -578,24 +371,21 @@ bool BridgedPassContext::shouldExpand(BridgedType ty) const {
   return swift::shouldExpand(mod, ty.unbridged());
 }
 
-BridgedDeclObj BridgedPassContext::getCurrentModuleContext() const {
-  return {invocation->getPassManager()->getModule()->getSwiftModule()};
-}
-
 bool BridgedPassContext::enableWMORequiredDiagnostics() const {
   swift::SILModule *mod = invocation->getPassManager()->getModule();
   return mod->getOptions().EnableWMORequiredDiagnostics;
 }
 
+bool BridgedPassContext::noAllocations() const {
+  swift::SILModule *mod = invocation->getPassManager()->getModule();
+  return mod->getOptions().NoAllocations;
+}
+
 bool BridgedPassContext::enableAddressDependencies() const {
   swift::SILModule *mod = invocation->getPassManager()->getModule();
   return mod->getOptions().EnableAddressDependencies;
 }
 
-static_assert((int)BridgedPassContext::SILStage::Raw == (int)swift::SILStage::Raw);
-static_assert((int)BridgedPassContext::SILStage::Canonical == (int)swift::SILStage::Canonical);
-static_assert((int)BridgedPassContext::SILStage::Lowered == (int)swift::SILStage::Lowered);
-
 static_assert((int)BridgedPassContext::AssertConfiguration::Debug == (int)swift::SILOptions::Debug);
 static_assert((int)BridgedPassContext::AssertConfiguration::Release == (int)swift::SILOptions::Release);
 static_assert((int)BridgedPassContext::AssertConfiguration::Unchecked == (int)swift::SILOptions::Unchecked);
diff --git a/include/swift/SILOptimizer/PassManager/PassManager.h b/include/swift/SILOptimizer/PassManager/PassManager.h
index ea6a3983a831d..ca4a88399d7b9 100644
--- a/include/swift/SILOptimizer/PassManager/PassManager.h
+++ b/include/swift/SILOptimizer/PassManager/PassManager.h
@@ -18,7 +18,6 @@
 #include "swift/SILOptimizer/Analysis/Analysis.h"
 #include "swift/SILOptimizer/PassManager/PassPipeline.h"
 #include "swift/SILOptimizer/PassManager/Passes.h"
-#include "swift/SILOptimizer/Utils/SILSSAUpdater.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Casting.h"
@@ -52,66 +51,36 @@ void executePassPipelinePlan(SILModule *SM, const SILPassPipelinePlan &plan,
                              irgen::IRGenModule *IRMod = nullptr);
 
 /// Utility class to invoke Swift passes.
-class SwiftPassInvocation {
+class SwiftPassInvocation : public SILContext {
   /// Backlink to the pass manager.
   SILPassManager *passManager;
 
   /// The current transform.
   SILTransform *transform = nullptr;
 
-  /// The currently optimized function.
-  SILFunction *function = nullptr;
-
-  /// Non-null if this is an instruction pass, invoked from SILCombine.
+  /// Non-null if this is an instruction simplification, invoked from SILCombine.
   SILCombiner *silCombiner = nullptr;
 
-  /// Change notifications, collected during a pass run.
-  SILAnalysis::InvalidationKind changeNotifications =
-      SILAnalysis::InvalidationKind::Nothing;
-
-  bool functionTablesChanged = false;
-
-  /// All slabs, allocated by the pass.
-  SILModule::SlabList allocatedSlabs;
-
-  SILSSAUpdater *ssaUpdater = nullptr;
-
   SwiftPassInvocation *nestedSwiftPassInvocation = nullptr;
 
-  static constexpr int BlockSetCapacity = SILBasicBlock::numCustomBits;
-  char blockSetStorage[sizeof(BasicBlockSet) * BlockSetCapacity];
-  bool aliveBlockSets[BlockSetCapacity];
-  int numBlockSetsAllocated = 0;
-
-  static constexpr int NodeSetCapacity = SILNode::numCustomBits;
-  char nodeSetStorage[sizeof(NodeSet) * NodeSetCapacity];
-  bool aliveNodeSets[NodeSetCapacity];
-  int numNodeSetsAllocated = 0;
-
-  static constexpr int OperandSetCapacity = Operand::numCustomBits;
-  char operandSetStorage[sizeof(OperandSet) * OperandSetCapacity];
-  bool aliveOperandSets[OperandSetCapacity];
-  int numOperandSetsAllocated = 0;
-
-  int numClonersAllocated = 0;
-
   bool needFixStackNesting = false;
 
+  void verifyEverythingIsCleared();
+
   void endPass();
 
 public:
   SwiftPassInvocation(SILPassManager *passManager, SILFunction *function,
                          SILCombiner *silCombiner) :
-    passManager(passManager), function(function), silCombiner(silCombiner) {}
+    SILContext(function), passManager(passManager), silCombiner(silCombiner) {}
 
   SwiftPassInvocation(SILPassManager *passManager, SILTransform *transform,
                       SILFunction *function) :
-    passManager(passManager), transform(transform), function(function) {}
+    SILContext(function), passManager(passManager), transform(transform) {}
 
-  SwiftPassInvocation(SILPassManager *passManager) :
-    passManager(passManager) {}
+  SwiftPassInvocation(SILPassManager *passManager);
 
-  ~SwiftPassInvocation();
+  virtual ~SwiftPassInvocation();
 
   SILPassManager *getPassManager() const { return passManager; }
   
@@ -121,29 +90,20 @@ class SwiftPassInvocation {
 
   irgen::IRGenModule *getIRGenModule();
 
-  FixedSizeSlab *allocSlab(FixedSizeSlab *afterSlab);
-
-  FixedSizeSlab *freeSlab(FixedSizeSlab *slab);
-
-  BasicBlockSet *allocBlockSet();
-
-  void freeBlockSet(BasicBlockSet *set);
-
-  NodeSet *allocNodeSet();
-
-  void freeNodeSet(NodeSet *set);
-
-  OperandSet *allocOperandSet();
+  /// The top-level API to erase an instruction, called from the Swift pass.
+  void eraseInstruction(SILInstruction *inst, bool salvageDebugInfo) override;
 
-  void freeOperandSet(OperandSet *set);
+  SILFunction *createEmptyFunction(StringRef name, ArrayRef<SILParameterInfo> params,
+                                  bool hasSelfParam, SILFunction *fromFn) override;
 
-  /// The top-level API to erase an instruction, called from the Swift pass.
-  void eraseInstruction(SILInstruction *inst);
+  void moveFunctionBody(SILFunction *sourceFn, SILFunction *destFn) override;
 
-  /// Called by the pass when changes are made to the SIL.
-  void notifyChanges(SILAnalysis::InvalidationKind invalidationKind);
+  SILFunction *lookupStdlibFunction(StringRef name) override;
 
-  void notifyFunctionTablesChanged();
+  void initializeSSAUpdater(SILFunction *function, SILType type, ValueOwnershipKind ownership) override;
+  void SSAUpdater_addAvailableValue(SILBasicBlock *block, SILValue value) override;
+  SILValue SSAUpdater_getValueAtEndOfBlock(SILBasicBlock *block) override;
+  SILValue SSAUpdater_getValueInMiddleOfBlock(SILBasicBlock *block) override;
 
   /// Called by the pass manager before the pass starts running.
   void startModulePassRun(SILModuleTransform *transform);
@@ -163,31 +123,12 @@ class SwiftPassInvocation {
   /// Called by the SILCombiner when the instruction pass has finished.
   void finishedInstructionPassRun();
   
-  void beginTransformFunction(SILFunction *function);
-
-  void endTransformFunction();
-
   void beginVerifyFunction(SILFunction *function);
   void endVerifyFunction();
 
-  void notifyNewCloner() { numClonersAllocated++; }
-  void notifyClonerDestroyed() { numClonersAllocated--; }
-
   void setNeedFixStackNesting(bool newValue) { needFixStackNesting = newValue; }
   bool getNeedFixStackNesting() const { return needFixStackNesting; }
 
-  void initializeSSAUpdater(SILFunction *fn, SILType type,
-                            ValueOwnershipKind ownership) {
-    if (!ssaUpdater)
-      ssaUpdater = new SILSSAUpdater;
-    ssaUpdater->initialize(fn, type, ownership);
-  }
-
-  SILSSAUpdater *getSSAUpdater() const {
-    assert(ssaUpdater && "SSAUpdater not initialized");
-    return ssaUpdater;
-  }
-
   SwiftPassInvocation *initializeNestedSwiftPassInvocation(SILFunction *newFunction) {
     assert(!nestedSwiftPassInvocation && "Nested Swift pass invocation already initialized");
     nestedSwiftPassInvocation = new SwiftPassInvocation(passManager, transform, newFunction);
@@ -196,7 +137,7 @@ class SwiftPassInvocation {
 
   void deinitializeNestedSwiftPassInvocation() {
     assert(nestedSwiftPassInvocation && "Nested Swift pass invocation not initialized");
-    nestedSwiftPassInvocation->endTransformFunction();
+    nestedSwiftPassInvocation->finishedFunctionPassRun();
     delete nestedSwiftPassInvocation;
     nestedSwiftPassInvocation = nullptr;
   }
@@ -514,14 +455,8 @@ class SILPassManager {
   void viewCallGraph();
 };
 
-inline void SwiftPassInvocation::
-notifyChanges(SILAnalysis::InvalidationKind invalidationKind) {
-    changeNotifications = (SILAnalysis::InvalidationKind)
-        (changeNotifications | invalidationKind);
-}
-inline void SwiftPassInvocation::notifyFunctionTablesChanged() {
-  functionTablesChanged = true;
-}
+inline SwiftPassInvocation::SwiftPassInvocation(SILPassManager *passManager) :
+  SILContext(passManager->getModule()), passManager(passManager)  {}
 
 } // end namespace swift
 
diff --git a/include/swift/SILOptimizer/PassManager/Passes.def b/include/swift/SILOptimizer/PassManager/Passes.def
index c9a500bbb6686..062a3f1b9dc5d 100644
--- a/include/swift/SILOptimizer/PassManager/Passes.def
+++ b/include/swift/SILOptimizer/PassManager/Passes.def
@@ -51,7 +51,7 @@
 ///   This macro follows the same conventions as PASS(Id, Tag, Description),
 ///   but is used for IRGen passes which are built outside of the
 ///   SILOptimizer library.
-///   
+///
 ///   An IRGen pass is created by IRGen and needs to be registered with the pass
 ///   manager dynamically.
 #ifndef IRGEN_PASS
@@ -59,6 +59,8 @@
 #endif
 
 
+PASS(AllocBoxToStack, "allocbox-to-stack",
+     "stack promotion of box objects")
 PASS(CopyToBorrowOptimization, "copy-to-borrow-optimization",
      "Convert load [copy] instructions to load_borrow and remove copies of borrowed values")
 PASS(AliasInfoDumper, "dump-alias-info",
@@ -77,6 +79,8 @@ PASS(AddressEscapeInfoDumper, "dump-addr-escape-info",
      "Dumps address escape information")
 PASS(AccessDumper, "dump-access",
      "Dump access information")
+PASS(ConstantCapturePropagation, "constant-capture-propagation",
+     "Specialize closures with constant captures")
 PASS(ComputeEscapeEffects, "compute-escape-effects",
      "Computes function escape effects")
 PASS(ComputeSideEffects, "compute-side-effects",
@@ -140,16 +144,24 @@ PASS(StackPromotion, "stack-promotion",
      "Stack Promotion of Class Objects")
 PASS(UpdateBorrowedFrom, "update-borrowed-from",
      "Test pass for update borrowed-from instructions")
-// NOTE - ExperimentalSwiftBasedClosureSpecialization and AutodiffClosureSpecialization are a WIP
-PASS(ExperimentalSwiftBasedClosureSpecialization, "experimental-swift-based-closure-specialization",
-     "General closure-specialization pass written in Swift")
+PASS(MandatoryTempRValueElimination, "mandatory-temp-rvalue-elimination",
+     "Mandatory remove short-lived immutable temporary copies")
+PASS(TempRValueElimination, "temp-rvalue-elimination",
+     "Remove short-lived immutable temporary copies")
+PASS(TempLValueElimination, "temp-lvalue-elimination",
+     "Remove short-lived immutable temporary l-values")
+PASS(LoopInvariantCodeMotion, "loop-invariant-code-motion",
+     "New Loop Invariant Code Motion")
+
+PASS(ClosureSpecialization, "closure-specialization",
+     "Specialize functions with closure arguments")
 PASS(AutodiffClosureSpecialization, "autodiff-closure-specialization",
      "Autodiff specific closure-specialization pass")
 
+MODULE_PASS(MandatoryAllocBoxToStack, "mandatory-allocbox-to-stack",
+     "Mandatory stack promotion of box objects")
 MODULE_PASS(AsyncDemotion, "async-demotion",
      "Convert async functions to be synchronous")
-MODULE_PASS(RunUnitTests, "run-unit-tests",
-     "Runs the compiler internal unit tests")
 MODULE_PASS(FunctionUsesDumper, "dump-function-uses",
      "Dump the results of FunctionUses")
 MODULE_PASS(MandatoryPerformanceOptimizations, "mandatory-performance-optimizations",
@@ -160,6 +172,8 @@ MODULE_PASS(StackProtection, "stack-protection",
      "Decides which functions need stack protectors")
 MODULE_PASS(DiagnoseUnknownConstValues, "diagnose-unknown-const-values",
      "Diagnose any '@const' entities which could not be simplified to a compile-time value")
+MODULE_PASS(EmbeddedSwiftDiagnostics, "embedded-swift-diagnostics",
+     "Diagnose violations of Embedded Swift language restrictions")
 
 IRGEN_PASS(AllocStackHoisting, "alloc-stack-hoisting",
            "SIL alloc_stack Hoisting")
@@ -205,7 +219,7 @@ LEGACY_PASS(AccessMarkerElimination, "access-marker-elim",
      "Access Marker Elimination.")
 LEGACY_PASS(AddressLowering, "address-lowering",
      "SIL Address Lowering")
-LEGACY_PASS(AllocBoxToStack, "allocbox-to-stack",
+LEGACY_PASS(LegacyAllocBoxToStack, "legacy-allocbox-to-stack",
      "Stack Promotion of Box Objects")
 LEGACY_PASS(ArrayCountPropagation, "array-count-propagation",
      "Array Count Propagation")
@@ -223,8 +237,6 @@ LEGACY_PASS(CallerAnalysisPrinter, "caller-analysis-printer",
      "Print Caller Analysis for Testing")
 LEGACY_PASS(CapturePromotion, "capture-promotion",
      "Capture Promotion to Eliminate Escaping Boxes")
-LEGACY_PASS(CapturePropagation, "capture-prop",
-     "Captured Constant Propagation")
 LEGACY_PASS(ClosureSpecializer, "closure-specialize",
      "Closure Specialization on Constant Function Arguments")
 
@@ -318,8 +330,6 @@ LEGACY_PASS(MandatoryARCOpts, "mandatory-arc-opts",
      "Mandatory ARC Optimization")
 LEGACY_PASS(HighLevelCSE, "high-level-cse",
      "Common Subexpression Elimination on High-Level SIL")
-LEGACY_PASS(HighLevelLICM, "high-level-licm",
-     "Loop Invariant Code Motion in High-Level SIL")
 LEGACY_PASS(IVInfoPrinter, "iv-info-printer",
      "Print Induction Variable Information for Testing")
 LEGACY_PASS(LowerHopToActor, "lower-hop-to-actor",
@@ -332,8 +342,6 @@ LEGACY_PASS(JumpThreadSimplifyCFG, "jumpthread-simplify-cfg",
      "Simplify CFG via Jump Threading")
 LEGACY_PASS(LetPropertiesOpt, "let-properties-opt",
      "Let Property Optimization")
-LEGACY_PASS(LICM, "licm",
-     "Loop Invariant Code Motion")
 LEGACY_PASS(LateCodeMotion, "late-codemotion",
      "Late Code Motion with Release Hoisting")
 LEGACY_PASS(LateDeadFunctionAndGlobalElimination, "late-deadfuncelim",
@@ -354,6 +362,8 @@ LEGACY_PASS(LowerAggregateInstrs, "lower-aggregate-instrs",
      "Lower Aggregate SIL Instructions to Multiple Scalar Operations")
 LEGACY_PASS(MandatoryInlining, "mandatory-inlining",
      "Mandatory Inlining of Transparent Functions")
+LEGACY_PASS(InlineAlwaysInlining, "inline-always-inlining",
+     "Inlining of '@inline(always)' Functions")
 LEGACY_PASS(Mem2Reg, "mem2reg",
      "Memory to SSA Value Conversion to Remove Stack Allocation")
 LEGACY_PASS(MoveCondFailToPreds, "move-cond-fail-to-preds",
@@ -368,9 +378,6 @@ LEGACY_PASS(ModulePrinter, "module-printer",
      "Print the module")
 LEGACY_PASS(NestedSemanticFunctionCheck, "nested-semantic-function-check",
      "Diagnose improperly nested '@_semantics' functions")
-LEGACY_PASS(NonTransparentFunctionOwnershipModelEliminator,
-     "non-transparent-func-ownership-model-eliminator",
-     "Eliminate Ownership Annotations from non-transparent SIL Functions")
 LEGACY_PASS(RCIdentityDumper, "rc-id-dumper",
      "Print Reference Count Identities")
 LEGACY_PASS(AlwaysInlineInliner, "always-inline",
@@ -399,10 +406,6 @@ LEGACY_PASS(PerformanceSILLinker, "performance-linker",
      "Deserialize all referenced SIL functions")
 LEGACY_PASS(RawSILInstLowering, "raw-sil-inst-lowering",
      "Lower all raw SIL instructions to canonical equivalents.")
-LEGACY_PASS(TempLValueOpt, "temp-lvalue-opt",
-     "Remove short-lived immutable temporary l-values")
-LEGACY_PASS(TempRValueOpt, "temp-rvalue-opt",
-     "Remove short-lived immutable temporary copies")
 LEGACY_PASS(IRGenPrepare, "irgen-prepare",
      "Cleanup SIL in preparation for IRGen")
 LEGACY_PASS(SendNonSendable, "send-non-sendable",
diff --git a/include/swift/SILOptimizer/Utils/BasicBlockOptUtils.h b/include/swift/SILOptimizer/Utils/BasicBlockOptUtils.h
index d7402cc809e05..0568861f61f92 100644
--- a/include/swift/SILOptimizer/Utils/BasicBlockOptUtils.h
+++ b/include/swift/SILOptimizer/Utils/BasicBlockOptUtils.h
@@ -164,6 +164,8 @@ class SinkAddressProjections {
   ///
   /// getInBlockProjectionOperandValues() can be called before or after cloning.
   bool cloneProjections();
+
+  SWIFT_DEBUG_DUMP;
 };
 
 /// Clone a single basic block and any required successor edges within the same
diff --git a/include/swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h b/include/swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h
deleted file mode 100644
index c683973489e57..0000000000000
--- a/include/swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h
+++ /dev/null
@@ -1,173 +0,0 @@
-//===--- CanonicalizeBorrowScope.h - Canonicalize OSSA borrows --*- C++ -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// This utility canonicalizes borrow scopes by rewriting them to restrict them
-/// to only the uses within the scope. To do this, it hoists forwarding
-/// operations out of the scope. This exposes many useless scopes that can be
-/// deleted, which in turn allows canonicalization of the outer owned values
-/// (via CanonicalizeOSSALifetime).
-///
-/// This does not shrink borrow scopes; it does not rewrite end_borrows.  For
-/// that, see ShrinkBorrowScope.
-///
-//===----------------------------------------------------------------------===//
-
-#ifndef SWIFT_SILOPTIMIZER_UTILS_CANONICALIZEBORROWSCOPES_H
-#define SWIFT_SILOPTIMIZER_UTILS_CANONICALIZEBORROWSCOPES_H
-
-#include "swift/Basic/GraphNodeWorklist.h"
-#include "swift/Basic/SmallPtrSetVector.h"
-#include "swift/SIL/OwnershipUtils.h"
-#include "swift/SIL/PrunedLiveness.h"
-#include "swift/SIL/SILInstruction.h"
-#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
-#include "swift/SILOptimizer/Analysis/NonLocalAccessBlockAnalysis.h"
-#include "swift/SILOptimizer/Utils/InstructionDeleter.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SetVector.h"
-
-namespace swift {
-
-class BasicCalleeAnalysis;
-
-//===----------------------------------------------------------------------===//
-//                       MARK: CanonicalizeBorrowScope
-//===----------------------------------------------------------------------===//
-
-class CanonicalizeBorrowScope {
-public:
-  /// Return true if \p inst is an instructions that forwards ownership is its
-  /// first operand and can be trivially duplicated, sunk to its uses, hoisted
-  /// outside a borrow scope and have it's ownership kind flipped from
-  /// guaranteed to owned if needed, as long as OSSA invariants are preserved.
-  static bool isRewritableOSSAForward(SILInstruction *inst);
-
-  /// Return the root of a borrowed extended lifetime for \p def or invalid.
-  ///
-  /// \p def may be any guaranteed value.
-  static SILValue getCanonicalBorrowedDef(SILValue def);
-
-private:
-  // The borrow that begins this scope.
-  BorrowedValue borrowedValue;
-
-  /// The function containing this scope.
-  SILFunction *function;
-
-  /// Pruned liveness for the extended live range including copies. For this
-  /// purpose, only consuming instructions are considered "lifetime
-  /// ending". end_borrows do not end a liverange that may include owned copies.
-  BitfieldRef<SSAPrunedLiveness> liveness;
-
-  InstructionDeleter &deleter;
-
-  /// Visited set for general def-use traversal that prevents revisiting values.
-  GraphNodeWorklist<SILValue, 8> defUseWorklist;
-
-  /// Visited set general CFG traversal that prevents revisiting blocks.
-  GraphNodeWorklist<SILBasicBlock *, 8> blockWorklist;
-
-  /// Record any copies outside the borrow scope that were updated. This
-  /// includes the outer copy that us used by outer uses and copies for any
-  /// hoisted forwarding instructions.
-  SmallVector<CopyValueInst *, 4> updatedCopies;
-
-  /// For borrowed defs, track per-block copies of the borrowed value that only
-  /// have uses outside the borrow scope and will not be removed by
-  /// canonicalization. These copies are effectively distinct OSSA lifetimes
-  /// that should be canonicalized separately.
-  llvm::SmallDenseMap<SILBasicBlock *, CopyValueInst *, 4> persistentCopies;
-
-public:
-  CanonicalizeBorrowScope(SILFunction *function, InstructionDeleter &deleter)
-      : function(function), deleter(deleter) {}
-
-  BorrowedValue getBorrowedValue() const { return borrowedValue; }
-
-  const SSAPrunedLiveness &getLiveness() const { return *liveness; }
-
-  InstructionDeleter &getDeleter() { return deleter; }
-
-  InstModCallbacks &getCallbacks() { return deleter.getCallbacks(); }
-
-  /// Top-level entry point for canonicalizing a SILFunctionArgument. This is a
-  /// straightforward canonicalization that can be performed as a stand-alone
-  /// utility anywhere.
-  bool canonicalizeFunctionArgument(SILFunctionArgument *arg);
-
-  /// Top-level entry point for canonicalizing any borrow scope.
-  ///
-  /// This creates OSSA compensation code outside the borrow scope. It should
-  /// only be called within copy propagation, which knows how to cleanup any new
-  /// copies outside the borrow scope, along with hoisted forwarding
-  /// instructions, etc.
-  bool canonicalizeBorrowScope(BorrowedValue borrow);
-
-  bool hasPersistentCopies() const { return !persistentCopies.empty(); }
-
-  bool isPersistentCopy(CopyValueInst *copy) const {
-    auto iter = persistentCopies.find(copy->getParent());
-    if (iter == persistentCopies.end()) {
-      return false;
-    }
-    return iter->second == copy;
-  }
-
-  // Get all the copies that inserted during canonicalizeBorrowScopes(). These
-  // are cleared at the next call to canonicalizeBorrowScopes().
-  ArrayRef<CopyValueInst *> getUpdatedCopies() const { return updatedCopies; }
-
-  using OuterUsers = llvm::SmallPtrSet<SILInstruction *, 8>;
-
-  SILValue findDefInBorrowScope(SILValue value);
-
-  template <typename Visitor>
-  bool visitBorrowScopeUses(SILValue innerValue, Visitor &visitor);
-
-  void beginVisitBorrowScopeUses() { defUseWorklist.clear(); }
-
-  void recordOuterCopy(CopyValueInst *copy) { updatedCopies.push_back(copy); }
-
-protected:
-  void initBorrow(BorrowedValue borrow) {
-    assert(borrow && persistentCopies.empty() &&
-           (!liveness || liveness->empty()));
-
-    borrowedValue = BorrowedValue();
-    defUseWorklist.clear();
-    blockWorklist.clear();
-    persistentCopies.clear();
-    updatedCopies.clear();
-
-    borrowedValue = borrow;
-    if (liveness)
-      liveness->initializeDef(borrowedValue.value);
-  }
-
-  bool computeBorrowLiveness();
-
-  void filterOuterBorrowUseInsts(OuterUsers &outerUseInsts);
-
-  bool consolidateBorrowScope();
-};
-
-bool shrinkBorrowScope(
-    BeginBorrowInst const &bbi, InstructionDeleter &deleter,
-    BasicCalleeAnalysis *calleeAnalysis,
-    SmallVectorImpl<CopyValueInst *> &modifiedCopyValueInsts);
-
-MoveValueInst *foldDestroysOfCopiedLexicalBorrow(BeginBorrowInst *bbi,
-                                                 DominanceInfo &dominanceTree,
-                                                 InstructionDeleter &deleter);
-} // namespace swift
-
-#endif // SWIFT_SILOPTIMIZER_UTILS_CANONICALIZEBORROWSCOPES_H
diff --git a/include/swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h b/include/swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h
deleted file mode 100644
index 2595baf82dc9e..0000000000000
--- a/include/swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h
+++ /dev/null
@@ -1,519 +0,0 @@
-//===- CanonicalizeOSSALifetime.h - Canonicalize OSSA lifetimes -*- C++ -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// Canonicalize the copies and destroys of a single owned OSSA value.
-///
-/// This top-level API rewrites the extended OSSA lifetime of a SILValue:
-///
-///     void canonicalizeValueLifetime(SILValue def, CanonicalizeOSSALifetime &)
-///
-/// The "extended lifetime" of the references defined by 'def' transitively
-/// includes the uses of 'def' itself along with the uses of any copies of
-/// 'def'. Canonicalization provably minimizes the OSSA lifetime and its copies
-/// by rewriting all copies and destroys. Only consuming uses that are not on
-/// the liveness boundary require a copy.
-///
-/// Example #1: The last consuming use ends the reference lifetime.
-///
-///     bb0(%arg : @owned $T, %addr : @trivial $*T):
-///       %copy = copy_value %arg : $T
-///       store %copy to [init] %addr : $*T
-///       debug_value %addr : $*T, expr op_deref
-///       destroy_value %arg : $T
-///
-/// Will be transformed to:
-///
-///     bb0(%arg : @owned $T, %addr : @trivial $*T):
-///       store %copy to [init] %addr : $*T
-///       debug_value %addr : $*T, expr op_deref
-///
-/// Example #2: Destroys are hoisted to the last use. Copies are inserted only
-/// at consumes within the lifetime (to directly satisfy ownership conventions):
-///
-///     bb0(%arg : @owned $T, %addr : @trivial $*T):
-///       %copy1 = copy_value %arg : $T
-///       store %arg to [init] %addr : $*T
-///       %_ = apply %_(%copy1) : $@convention(thin) (@guaranteed T) -> ()
-///       debug_value %addr : $*T, expr op_deref
-///       destroy_value %copy1 : $T
-///
-/// Will be transformed to:
-///
-///     bb0(%arg : @owned $T, %addr : @trivial $*T):
-///       %copy1 = copy_value %arg : $T
-///       store %copy1 to [init] %addr : $*T
-///       %_ = apply %_(%arg) : $@convention(thin) (@guaranteed T) -> ()
-///       destroy_value %arg : $T
-///       debug_value %addr : $*T, expr op_deref
-///
-/// Example #3: Handle control flow.
-///
-///     bb0(%arg : @owned $T):
-///       cond_br %_, bb1, bb2
-///     bb1:
-///       br bb3
-///     bb2:
-///       %copy = copy_value %arg : $T
-///       %_ = apply %_(%copy) : $@convention(thin) (@guaranteed T) -> ()
-///       destroy_value %copy : $T
-///       br bb3
-///     bb3:
-///       destroy_value %arg : $T
-///
-/// Will be transformed to:
-///
-///     bb0(%arg : @owned $T):
-///       cond_br %_, bb1, bb2
-///     bb1:
-///       destroy_value %arg : $T
-///       br bb3
-///     bb2:
-///       %_ = apply %_(%arg) : $@convention(thin) (@guaranteed T) -> ()
-///       destroy_value %arg : $T
-///       br bb3
-///     bb2:
-///       // The original destroy is deleted.
-///
-/// Pass Requirements:
-///
-///   This utility invalidates instructions but both uses and preserves
-///   NonLocalAccessBlockAnalysis.
-///
-///   The use-def walks in this utility, e.g. getCanonicalCopiedDef, assume no
-///   cycles in the data flow graph without a phi.
-///
-//===----------------------------------------------------------------------===//
-
-#ifndef SWIFT_SILOPTIMIZER_UTILS_CANONICALOSSALIFETIME_H
-#define SWIFT_SILOPTIMIZER_UTILS_CANONICALOSSALIFETIME_H
-
-#include "swift/Basic/SmallPtrSetVector.h"
-#include "swift/SIL/PrunedLiveness.h"
-#include "swift/SIL/SILInstruction.h"
-#include "swift/SILOptimizer/Analysis/DeadEndBlocksAnalysis.h"
-#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
-#include "swift/SILOptimizer/Analysis/NonLocalAccessBlockAnalysis.h"
-#include "swift/SILOptimizer/Utils/InstructionDeleter.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/Statistic.h"
-
-namespace swift {
-
-class BasicCalleeAnalysis;
-
-extern llvm::Statistic NumCopiesAndMovesEliminated;
-extern llvm::Statistic NumCopiesGenerated;
-
-/// Insert a copy on this operand. Trace and update stats.
-void copyLiveUse(Operand *use, InstModCallbacks &instModCallbacks);
-
-/// Diagnose that the given value is a move only type for which \p use causes a
-/// need to copy the move only value.
-///
-/// copy on this operand. Trace and update stats.
-void diagnoseRequiredCopyOfMoveOnly(Operand *use,
-                                    InstModCallbacks &instModCallbacks);
-
-/// Information about consumes on the extended-lifetime boundary. Consuming uses
-/// within the lifetime are not included--they will consume a copy after
-/// rewriting. For borrowed def values, the consumes do not include the end of
-/// the borrow scope, rather the consumes transitively include consumes of any
-/// owned copies of the borrowed value.
-///
-/// This result remains valid during copy rewriting. The only instructions
-/// referenced it contains are consumes that cannot be deleted.
-class CanonicalOSSAConsumeInfo final {
-  /// Map blocks on the lifetime boundary to the last consuming instruction.
-  llvm::SmallDenseMap<SILBasicBlock *, SILInstruction *, 4> finalBlockConsumes;
-
-  /// The instructions on the availability boundary of the dead-end region where
-  /// this value is not consumed.
-  SmallPtrSet<SILInstruction *, 4> unreachableLifetimeEnds;
-
-public:
-  void clear() { finalBlockConsumes.clear(); }
-
-  bool empty() { return finalBlockConsumes.empty(); }
-
-  bool hasUnclaimedConsumes() const { return !finalBlockConsumes.empty(); }
-
-  void recordFinalConsume(SILInstruction *inst) {
-    assert(!finalBlockConsumes.count(inst->getParent()));
-    finalBlockConsumes[inst->getParent()] = inst;
-  }
-
-  // Return true if this instruction is marked as a final consume point of the
-  // current def's live range. A consuming instruction can only be claimed once
-  // because instructions like `tuple` can consume the same value via multiple
-  // operands.
-  bool claimConsume(SILInstruction *inst) {
-    auto destroyPos = finalBlockConsumes.find(inst->getParent());
-    if (destroyPos != finalBlockConsumes.end() && destroyPos->second == inst) {
-      finalBlockConsumes.erase(destroyPos);
-      return true;
-    }
-    return false;
-  }
-
-  void recordUnreachableLifetimeEnd(SILInstruction *inst) {
-    unreachableLifetimeEnds.insert(inst);
-  }
-
-  bool isUnreachableLifetimeEnd(SILInstruction *inst) {
-    return unreachableLifetimeEnds.contains(inst);
-  }
-
-  CanonicalOSSAConsumeInfo() {}
-  CanonicalOSSAConsumeInfo(CanonicalOSSAConsumeInfo const &) = delete;
-  CanonicalOSSAConsumeInfo &
-  operator=(CanonicalOSSAConsumeInfo const &) = delete;
-  SWIFT_ASSERT_ONLY_DECL(void dump() const LLVM_ATTRIBUTE_USED);
-};
-
-enum PruneDebugInsts_t : bool {
-  DontPruneDebugInsts = false,
-  PruneDebugInsts = true,
-};
-
-enum MaximizeLifetime_t : bool {
-  DontMaximizeLifetime = false,
-  MaximizeLifetime = true,
-};
-
-/// Canonicalize OSSA lifetimes.
-///
-/// Allows the allocation of analysis state to be reused across calls to
-/// canonicalizeValueLifetime().
-///
-/// TODO: Move all the private per-definition members into an implementation
-/// class in the .cpp file.
-class CanonicalizeOSSALifetime final {
-public:
-  /// Find the original definition of a potentially copied value. \p copiedValue
-  /// must be an owned value. It is usually a copy but may also be a destroy.
-  ///
-  /// This single helper specifies the root of an owned extended lifetime. Owned
-  /// extended lifetimes may not overlap. This ensures that canonicalization can
-  /// run as a utility without invalidating instruction worklists in the client,
-  /// as long as the client works on each canonical def independently.
-  ///
-  /// If the source of a copy is guaranteed, then the copy itself is the root of
-  /// an owned extended lifetime. Note that it will also be part of a borrowed
-  /// extended lifetime, which will be canonicalized separately by
-  /// CanonicalizeBorrowScope.
-  ///
-  /// This use-def walk must be consistent with the def-use walks performed
-  /// within the canonicalizeValueLifetime() and canonicalizeBorrowScopes()
-  /// implementations.
-  static SILValue getCanonicalCopiedDef(SILValue v) {
-    while (auto *copy = dyn_cast<CopyValueInst>(v)) {
-      auto def = copy->getOperand();
-      if (def->getOwnershipKind() != OwnershipKind::Owned) {
-        // This guaranteed value cannot be handled, treat the copy as an owned
-        // live range def instead.
-        return copy;
-      }
-      v = def;
-    }
-    return v;
-  }
-
-private:
-  /// If true, then debug_value instructions outside of non-debug
-  /// liveness may be pruned during canonicalization.
-  const PruneDebugInsts_t pruneDebugMode;
-
-  /// If true, lifetimes will not be shortened except when necessary to avoid
-  /// copies.
-  const MaximizeLifetime_t maximizeLifetime;
-
-  SILFunction *function;
-
-  // If present, will be used to ensure that the lifetime is not shortened to
-  // end inside an access scope which it previously enclosed.  (Note that ending
-  // before such an access scope is fine regardless.)
-  //
-  // For details, see extendLivenessThroughOverlappingAccess.
-  NonLocalAccessBlockAnalysis *accessBlockAnalysis;
-  // Lazily initialize accessBlocks only when
-  // extendLivenessThroughOverlappingAccess is invoked.
-  NonLocalAccessBlocks *accessBlocks = nullptr;
-
-  DeadEndBlocksAnalysis *deadEndBlocksAnalysis;
-
-  DominanceInfo *domTree = nullptr;
-
-  BasicCalleeAnalysis *calleeAnalysis;
-
-  InstructionDeleter &deleter;
-
-  /// The SILValue to canonicalize.
-  SILValue currentDef;
-
-  /// Instructions beyond which liveness is not extended by destroy uses.
-  ArrayRef<SILInstruction *> currentLexicalLifetimeEnds;
-
-  /// Original points in the CFG where the current value's lifetime is consumed
-  /// or destroyed.  Each block either contains a consuming instruction (e.g.
-  /// `destroy_value`) or is on the availability boundary of the value in a
-  /// dead-end region (e.g. `unreachable`).
-  ///
-  /// For guaranteed values it remains empty. A backward walk from these blocks
-  /// must discover all uses on paths that lead to a return or throw.
-  ///
-  /// These blocks are not necessarily in the pruned live blocks since
-  /// pruned liveness does not consider destroy_values.
-  llvm::SmallSetVector<SILBasicBlock *, 8> consumingBlocks;
-
-  /// Record all interesting debug_value instructions here rather then treating
-  /// them like a normal use. An interesting debug_value is one that may lie
-  /// outside the pruned liveness at the time it is discovered.
-  llvm::SmallPtrSet<DebugValueInst *, 8> debugValues;
-
-  struct Def {
-    enum Kind {
-      Root,
-      Copy,
-      BorrowedFrom,
-      Reborrow,
-    };
-    const Kind kind;
-    const SILValue value;
-    static Def root(SILValue value) { return {Root, value}; }
-    static Def copy(CopyValueInst *cvi) { return {Copy, cvi}; }
-    static Def borrowedFrom(BorrowedFromInst *bfi) {
-      return {BorrowedFrom, bfi};
-    }
-    static Def reborrow(SILArgument *argument) { return {Reborrow, argument}; }
-
-  private:
-    Def(Kind kind, SILValue value) : kind(kind), value(value) {}
-  };
-
-  /// The defs derived from currentDef whose uses are added to liveness.
-  SmallVector<Def, 8> discoveredDefs;
-
-  /// The blocks that were discovered by PrunedLiveness.
-  SmallVector<SILBasicBlock *, 32> discoveredBlocks;
-
-  /// Pruned liveness for the extended live range including copies. For this
-  /// purpose, only consuming instructions are considered "lifetime
-  /// ending". end_borrows do not end a liverange that may include owned copies.
-  BitfieldRef<SSAPrunedLiveness> liveness;
-
-  /// The destroys of the value.  These are not uses, but need to be recorded so
-  /// that we know when the last use in a consuming block is (without having to
-  /// repeatedly do use-def walks from destroys).
-  SmallPtrSetVector<SILInstruction *, 8> destroys;
-
-  /// Information about consuming instructions discovered in this canonical OSSA
-  /// lifetime.
-  CanonicalOSSAConsumeInfo consumes;
-
-public:
-  /// When rewriting destroys, is this an instruction which destroys should not
-  /// be hoisted over to avoid churn and infinite looping.
-  static bool ignoredByDestroyHoisting(SILInstructionKind kind) {
-    switch (kind) {
-    case SILInstructionKind::DebugValueInst:
-    case SILInstructionKind::DestroyValueInst:
-    case SILInstructionKind::CopyValueInst:
-    case SILInstructionKind::BeginBorrowInst:
-    case SILInstructionKind::EndBorrowInst:
-    case SILInstructionKind::FunctionRefInst:
-    case SILInstructionKind::EnumInst:
-    case SILInstructionKind::StructInst:
-      return true;
-    default:
-      return false;
-    }
-  }
-
-  /// Stack-allocated liveness for a single SSA def.
-  struct LivenessState {
-    BitfieldRef<SSAPrunedLiveness>::StackState state;
-
-    LivenessState(CanonicalizeOSSALifetime &parent, SILValue def,
-                  ArrayRef<SILInstruction *> lexicalLifetimeEnds)
-        : state(parent.liveness, def->getFunction()) {
-      parent.initializeLiveness(def, lexicalLifetimeEnds);
-    }
-  };
-
-  CanonicalizeOSSALifetime(
-      PruneDebugInsts_t pruneDebugMode, MaximizeLifetime_t maximizeLifetime,
-      SILFunction *function, NonLocalAccessBlockAnalysis *accessBlockAnalysis,
-      DeadEndBlocksAnalysis *deadEndBlocksAnalysis, DominanceInfo *domTree,
-      BasicCalleeAnalysis *calleeAnalysis, InstructionDeleter &deleter)
-      : pruneDebugMode(pruneDebugMode), maximizeLifetime(maximizeLifetime),
-        function(function), accessBlockAnalysis(accessBlockAnalysis),
-        deadEndBlocksAnalysis(deadEndBlocksAnalysis), domTree(domTree),
-        calleeAnalysis(calleeAnalysis), deleter(deleter) {}
-
-  SILValue getCurrentDef() const { return currentDef; }
-
-  void initializeLiveness(SILValue def,
-                          ArrayRef<SILInstruction *> lexicalLifetimeEnds) {
-    assert(consumingBlocks.empty() && debugValues.empty());
-    clear();
-
-    currentDef = def;
-    currentLexicalLifetimeEnds = lexicalLifetimeEnds;
-
-    liveness->initializeDiscoveredBlocks(&discoveredBlocks);
-    liveness->initializeDef(getCurrentDef());
-  }
-
-  void clear() {
-    // Clear the access blocks analysis pointer in case the client invalidates
-    // the analysis.  If the client did, the analysis will be recomputed in
-    // extendLivenessThroughOverlappingAccess; if it didn't, the analysis
-    // pointer will just be set back to its old value when the analysis' cache
-    // is consulted in extendLivenessThroughOverlappingAccess.
-    accessBlocks = nullptr;
-
-    consumingBlocks.clear();
-    debugValues.clear();
-    discoveredBlocks.clear();
-    consumes.clear();
-    destroys.clear();
-  }
-
-  /// Top-Level API: rewrites copies and destroys within \p def's extended
-  /// lifetime.
-  ///
-  /// For lexical values, canonicalization respects deinit barriers, introducing
-  /// copies as needed to maintain lifetimes beyond final consuming uses to the
-  /// original lexical lifetime end.  When a lexical value is explicitly
-  /// consumed (via the `consume` keyword), however, the lifetime does not
-  /// extend to original destroys beyond that consume--the value must be dead
-  /// after the corresponding marker instructions (`move_value`); to support
-  /// this shortening, the marker instructions must be provided as \p
-  /// lexicalLifetimeEnds. When provided, deinit barriers will be respected
-  /// except to the extent doing so would result in the value being live after
-  /// the marker instructions.
-  ///
-  /// Return true if any change was made to \p def's extended lifetime. \p def
-  /// itself will not be deleted and no instructions outside of \p def's
-  /// extended lifetime will be affected (only copies and destroys are
-  /// rewritten).
-  ///
-  /// This only deletes instructions within \p def's extended lifetime. Use
-  /// InstructionDeleter::cleanUpDeadInstructions() to recursively delete dead
-  /// operands.
-  bool canonicalizeValueLifetime(
-      SILValue def, ArrayRef<SILInstruction *> lexicalLifetimeEnds = {});
-
-  /// Compute the liveness information for \p def. But do not do any rewriting
-  /// or computation of boundaries.
-  ///
-  /// The intention is that this is used if one wants to emit diagnostics using
-  /// the liveness information before doing any rewriting.
-  ///
-  /// Requires an active on-stack instance of LivenessState.
-  ///
-  ///     LivenessState livenessState(*this, def);
-  ///
-  bool computeLiveness();
-
-  /// Given the already computed liveness boundary for the given def, rewrite
-  /// copies of def as appropriate.
-  ///
-  /// Requires an active on-stack instance of LivenessState.
-  void rewriteLifetimes();
-
-  /// Return the pure original boundary just based off of liveness information
-  /// without maximizing or extending liveness.
-  ///
-  /// Requires an active on-stack instance of LivenessState.
-  void findOriginalBoundary(PrunedLivenessBoundary &resultingOriginalBoundary);
-
-  InstModCallbacks &getCallbacks() { return deleter.getCallbacks(); }
-
-  using IsInterestingUser = PrunedLiveness::IsInterestingUser;
-
-  /// Helper method that returns the isInterestingUser status of \p user in the
-  /// passed in Liveness.
-  ///
-  /// NOTE: Only call this after calling computeLivenessBoundary or the results
-  /// will not be initialized.
-  IsInterestingUser isInterestingUser(SILInstruction *user) const {
-    return liveness->isInterestingUser(user);
-  }
-
-  using LifetimeEndingUserRange = PrunedLiveness::LifetimeEndingUserRange;
-  LifetimeEndingUserRange getLifetimeEndingUsers() const {
-    return liveness->getLifetimeEndingUsers();
-  }
-
-  using NonLifetimeEndingUserRange = PrunedLiveness::NonLifetimeEndingUserRange;
-  NonLifetimeEndingUserRange getNonLifetimeEndingUsers() const {
-    return liveness->getNonLifetimeEndingUsers();
-  }
-
-  using UserRange = PrunedLiveness::ConstUserRange;
-  UserRange getUsers() const { return liveness->getAllUsers(); }
-
-private:
-  bool respectsDeinitBarriers() const {
-    if (!currentDef->isLexical())
-      return false;
-    if (currentDef->getFunction()->forceEnableLexicalLifetimes())
-      return true;
-    auto &module = currentDef->getFunction()->getModule();
-    return module.getASTContext().SILOpts.supportsLexicalLifetimes(module);
-  }
-
-  void recordDebugValue(DebugValueInst *dvi) { debugValues.insert(dvi); }
-
-  void recordConsumingUse(Operand *use) { recordConsumingUser(use->getUser()); }
-  /// Record that the value is consumed at `user`.
-  ///
-  /// Either `user` is a consuming use (e.g. `destroy_value`) or it is the
-  /// terminator of a block on the availability boundary of the value in a
-  /// dead-end region (e.g. `unreachable`).
-  void recordConsumingUser(SILInstruction *user) {
-    consumingBlocks.insert(user->getParent());
-  }
-  void recordUnreachableLifetimeEnd(SILInstruction *user) {
-    recordConsumingUser(user);
-    consumes.recordUnreachableLifetimeEnd(user);
-  }
-  bool computeCanonicalLiveness();
-
-  bool endsAccessOverlappingPrunedBoundary(SILInstruction *inst);
-
-  void extendLivenessThroughOverlappingAccess();
-
-  void findExtendedBoundary(PrunedLivenessBoundary const &originalBoundary,
-                            PrunedLivenessBoundary &boundary);
-
-  void extendLivenessToDeadEnds();
-  void extendLexicalLivenessToDeadEnds();
-  void extendLivenessToDeinitBarriers();
-
-  void extendUnconsumedLiveness(PrunedLivenessBoundary const &boundary);
-  void visitExtendedUnconsumedBoundary(
-      ArrayRef<SILInstruction *> ends,
-      llvm::function_ref<void(SILInstruction *, PrunedLiveness::LifetimeEnding)>
-          visitor);
-
-  void insertDestroysOnBoundary(PrunedLivenessBoundary const &boundary,
-                                SmallVectorImpl<DestroyValueInst *> &destroys);
-
-  void rewriteCopies(SmallVectorImpl<DestroyValueInst *> const &destroys);
-};
-
-} // end namespace swift
-
-#endif
diff --git a/include/swift/SILOptimizer/Utils/Devirtualize.h b/include/swift/SILOptimizer/Utils/Devirtualize.h
index 4b647d35958d3..bf9b0a3b60077 100644
--- a/include/swift/SILOptimizer/Utils/Devirtualize.h
+++ b/include/swift/SILOptimizer/Utils/Devirtualize.h
@@ -76,7 +76,7 @@ bool canDevirtualizeClassMethod(FullApplySite AI, ClassDecl *CD,
                                 CanType ClassType,
                                 OptRemark::Emitter *ORE = nullptr,
                                 bool isEffectivelyFinalMethod = false);
-SILFunction *getTargetClassMethod(SILModule &M, ClassDecl *CD,
+SILFunction *getTargetClassMethod(SILModule &M, FullApplySite as, ClassDecl *CD,
                                   CanType ClassType, MethodInst *MI);
 CanType getSelfInstanceType(CanType ClassOrMetatypeType);
 
diff --git a/include/swift/SILOptimizer/Utils/GenericCloner.h b/include/swift/SILOptimizer/Utils/GenericCloner.h
index cc049f1bda00a..bd00f68181e85 100644
--- a/include/swift/SILOptimizer/Utils/GenericCloner.h
+++ b/include/swift/SILOptimizer/Utils/GenericCloner.h
@@ -30,8 +30,8 @@
 namespace swift {
 
 class GenericCloner
-  : public TypeSubstCloner<GenericCloner, SILOptFunctionBuilder> {
-  using SuperTy = TypeSubstCloner<GenericCloner, SILOptFunctionBuilder>;
+  : public TypeSubstCloner<GenericCloner> {
+  using SuperTy = TypeSubstCloner<GenericCloner>;
 
   SILOptFunctionBuilder &FuncBuilder;
   SerializedKind_t Serialized;
diff --git a/include/swift/SILOptimizer/Utils/Generics.h b/include/swift/SILOptimizer/Utils/Generics.h
index 493dbcd1c0bd5..0dc4743ef3811 100644
--- a/include/swift/SILOptimizer/Utils/Generics.h
+++ b/include/swift/SILOptimizer/Utils/Generics.h
@@ -84,7 +84,8 @@ class ReabstractionInfo {
   /// specializer.
   bool ConvertIndirectToDirect = true;
 
-  /// If true, drop unused arguments.
+  /// If true, drop unused arguments. Dropping unused arguments is a
+  /// prerequisite before promoting an indirect argument to a direct argument.
   /// See `droppedArguments`.
   bool dropUnusedArguments = false;
 
@@ -204,7 +205,7 @@ class ReabstractionInfo {
   ReabstractionInfo(ModuleDecl *targetModule, bool isModuleWholeModule,
                     ApplySite Apply, SILFunction *Callee,
                     SubstitutionMap ParamSubs, SerializedKind_t Serialized,
-                    bool ConvertIndirectToDirect, bool dropMetatypeArgs,
+                    bool ConvertIndirectToDirect, bool dropUnusedArguments,
                     OptRemark::Emitter *ORE = nullptr);
 
   /// Constructs the ReabstractionInfo for generic function \p Callee with
diff --git a/include/swift/SILOptimizer/Utils/LoopUtils.h b/include/swift/SILOptimizer/Utils/LoopUtils.h
index 9c1c07e7f157e..f34f449a73fda 100644
--- a/include/swift/SILOptimizer/Utils/LoopUtils.h
+++ b/include/swift/SILOptimizer/Utils/LoopUtils.h
@@ -28,6 +28,7 @@ class SILInstruction;
 class SILLoop;
 class DominanceInfo;
 class SILLoopInfo;
+class DeadEndBlocks;
 
 /// Canonicalize the loop for rotation and downstream passes.
 ///
@@ -40,7 +41,7 @@ bool canonicalizeAllLoops(DominanceInfo *DT, SILLoopInfo *LI);
 
 /// Check whether it is safe to duplicate this instruction when duplicating
 /// this loop by unrolling or versioning.
-bool canDuplicateLoopInstruction(SILLoop *L, SILInstruction *Inst);
+bool canDuplicateLoopInstruction(SILLoop *L, SILInstruction *Inst, DeadEndBlocks *deb);
 
 /// A visitor that visits loops in a function in a bottom up order. It only
 /// performs the visit.
diff --git a/include/swift/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.h b/include/swift/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.h
new file mode 100644
index 0000000000000..f503df0ad7c6b
--- /dev/null
+++ b/include/swift/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.h
@@ -0,0 +1,173 @@
+//===- OSSACanonicalizeGuaranteed.h - Canonicalize OSSA borrows -*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// This utility canonicalizes borrow scopes by rewriting them to restrict them
+/// to only the uses within the scope. To do this, it hoists forwarding
+/// operations out of the scope. This exposes many useless scopes that can be
+/// deleted, which in turn allows canonicalization of the outer owned values
+/// (via OSSACanonicalizeOwned).
+///
+/// This does not shrink borrow scopes; it does not rewrite end_borrows.  For
+/// that, see ShrinkBorrowScope.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SILOPTIMIZER_UTILS_CANONICALIZEBORROWSCOPES_H
+#define SWIFT_SILOPTIMIZER_UTILS_CANONICALIZEBORROWSCOPES_H
+
+#include "swift/Basic/GraphNodeWorklist.h"
+#include "swift/Basic/SmallPtrSetVector.h"
+#include "swift/SIL/OwnershipUtils.h"
+#include "swift/SIL/PrunedLiveness.h"
+#include "swift/SIL/SILInstruction.h"
+#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
+#include "swift/SILOptimizer/Analysis/NonLocalAccessBlockAnalysis.h"
+#include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SetVector.h"
+
+namespace swift {
+
+class BasicCalleeAnalysis;
+
+//===----------------------------------------------------------------------===//
+//                       MARK: OSSACanonicalizeGuaranteed
+//===----------------------------------------------------------------------===//
+
+class OSSACanonicalizeGuaranteed {
+public:
+  /// Return true if \p inst is an instructions that forwards ownership is its
+  /// first operand and can be trivially duplicated, sunk to its uses, hoisted
+  /// outside a borrow scope and have it's ownership kind flipped from
+  /// guaranteed to owned if needed, as long as OSSA invariants are preserved.
+  static bool isRewritableOSSAForward(SILInstruction *inst);
+
+  /// Return the root of a borrowed extended lifetime for \p def or invalid.
+  ///
+  /// \p def may be any guaranteed value.
+  static SILValue getCanonicalBorrowedDef(SILValue def);
+
+private:
+  // The borrow that begins this scope.
+  BorrowedValue borrowedValue;
+
+  /// The function containing this scope.
+  SILFunction *function;
+
+  /// Pruned liveness for the extended live range including copies. For this
+  /// purpose, only consuming instructions are considered "lifetime
+  /// ending". end_borrows do not end a liverange that may include owned copies.
+  BitfieldRef<SSAPrunedLiveness> liveness;
+
+  InstructionDeleter &deleter;
+
+  /// Visited set for general def-use traversal that prevents revisiting values.
+  GraphNodeWorklist<SILValue, 8> defUseWorklist;
+
+  /// Visited set general CFG traversal that prevents revisiting blocks.
+  GraphNodeWorklist<SILBasicBlock *, 8> blockWorklist;
+
+  /// Record any copies outside the borrow scope that were updated. This
+  /// includes the outer copy that us used by outer uses and copies for any
+  /// hoisted forwarding instructions.
+  SmallVector<CopyValueInst *, 4> updatedCopies;
+
+  /// For borrowed defs, track per-block copies of the borrowed value that only
+  /// have uses outside the borrow scope and will not be removed by
+  /// canonicalization. These copies are effectively distinct OSSA lifetimes
+  /// that should be canonicalized separately.
+  llvm::SmallDenseMap<SILBasicBlock *, CopyValueInst *, 4> persistentCopies;
+
+public:
+  OSSACanonicalizeGuaranteed(SILFunction *function, InstructionDeleter &deleter)
+      : function(function), deleter(deleter) {}
+
+  BorrowedValue getBorrowedValue() const { return borrowedValue; }
+
+  const SSAPrunedLiveness &getLiveness() const { return *liveness; }
+
+  InstructionDeleter &getDeleter() { return deleter; }
+
+  InstModCallbacks &getCallbacks() { return deleter.getCallbacks(); }
+
+  /// Top-level entry point for canonicalizing a SILFunctionArgument. This is a
+  /// straightforward canonicalization that can be performed as a stand-alone
+  /// utility anywhere.
+  bool canonicalizeFunctionArgument(SILFunctionArgument *arg);
+
+  /// Top-level entry point for canonicalizing any borrow scope.
+  ///
+  /// This creates OSSA compensation code outside the borrow scope. It should
+  /// only be called within copy propagation, which knows how to cleanup any new
+  /// copies outside the borrow scope, along with hoisted forwarding
+  /// instructions, etc.
+  bool canonicalizeBorrowScope(BorrowedValue borrow);
+
+  bool hasPersistentCopies() const { return !persistentCopies.empty(); }
+
+  bool isPersistentCopy(CopyValueInst *copy) const {
+    auto iter = persistentCopies.find(copy->getParent());
+    if (iter == persistentCopies.end()) {
+      return false;
+    }
+    return iter->second == copy;
+  }
+
+  // Get all the copies that inserted during canonicalizeBorrowScopes(). These
+  // are cleared at the next call to canonicalizeBorrowScopes().
+  ArrayRef<CopyValueInst *> getUpdatedCopies() const { return updatedCopies; }
+
+  using OuterUsers = llvm::SmallPtrSet<SILInstruction *, 8>;
+
+  SILValue findDefInBorrowScope(SILValue value);
+
+  template <typename Visitor>
+  bool visitBorrowScopeUses(SILValue innerValue, Visitor &visitor);
+
+  void beginVisitBorrowScopeUses() { defUseWorklist.clear(); }
+
+  void recordOuterCopy(CopyValueInst *copy) { updatedCopies.push_back(copy); }
+
+protected:
+  void initBorrow(BorrowedValue borrow) {
+    assert(borrow && persistentCopies.empty() &&
+           (!liveness || liveness->empty()));
+
+    borrowedValue = BorrowedValue();
+    defUseWorklist.clear();
+    blockWorklist.clear();
+    persistentCopies.clear();
+    updatedCopies.clear();
+
+    borrowedValue = borrow;
+    if (liveness)
+      liveness->initializeDef(borrowedValue.value);
+  }
+
+  bool computeBorrowLiveness();
+
+  void filterOuterBorrowUseInsts(OuterUsers &outerUseInsts);
+
+  bool consolidateBorrowScope();
+};
+
+bool shrinkBorrowScope(
+    BeginBorrowInst const &bbi, InstructionDeleter &deleter,
+    BasicCalleeAnalysis *calleeAnalysis,
+    SmallVectorImpl<CopyValueInst *> &modifiedCopyValueInsts);
+
+MoveValueInst *foldDestroysOfCopiedLexicalBorrow(BeginBorrowInst *bbi,
+                                                 DominanceInfo &dominanceTree,
+                                                 InstructionDeleter &deleter);
+} // namespace swift
+
+#endif // SWIFT_SILOPTIMIZER_UTILS_CANONICALIZEBORROWSCOPES_H
diff --git a/include/swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h b/include/swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h
new file mode 100644
index 0000000000000..407feecaba3d3
--- /dev/null
+++ b/include/swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h
@@ -0,0 +1,533 @@
+//===- OSSACanonicalizeOwned.h - Canonicalize OSSA lifetimes -*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// Canonicalize the copies and destroys of a single owned OSSA value.
+///
+/// This top-level API rewrites the extended OSSA lifetime of a SILValue:
+///
+///     void canonicalizeValueLifetime(SILValue def, OSSACanonicalizeOwned &)
+///
+/// The "extended lifetime" of the references defined by 'def' transitively
+/// includes the uses of 'def' itself along with the uses of any copies of
+/// 'def'. Canonicalization provably minimizes the OSSA lifetime and its copies
+/// by rewriting all copies and destroys. Only consuming uses that are not on
+/// the liveness boundary require a copy.
+///
+/// Example #1: The last consuming use ends the reference lifetime.
+///
+///     bb0(%arg : @owned $T, %addr : @trivial $*T):
+///       %copy = copy_value %arg : $T
+///       store %copy to [init] %addr : $*T
+///       debug_value %addr : $*T, expr op_deref
+///       destroy_value %arg : $T
+///
+/// Will be transformed to:
+///
+///     bb0(%arg : @owned $T, %addr : @trivial $*T):
+///       store %copy to [init] %addr : $*T
+///       debug_value %addr : $*T, expr op_deref
+///
+/// Example #2: Destroys are hoisted to the last use. Copies are inserted only
+/// at consumes within the lifetime (to directly satisfy ownership conventions):
+///
+///     bb0(%arg : @owned $T, %addr : @trivial $*T):
+///       %copy1 = copy_value %arg : $T
+///       store %arg to [init] %addr : $*T
+///       %_ = apply %_(%copy1) : $@convention(thin) (@guaranteed T) -> ()
+///       debug_value %addr : $*T, expr op_deref
+///       destroy_value %copy1 : $T
+///
+/// Will be transformed to:
+///
+///     bb0(%arg : @owned $T, %addr : @trivial $*T):
+///       %copy1 = copy_value %arg : $T
+///       store %copy1 to [init] %addr : $*T
+///       %_ = apply %_(%arg) : $@convention(thin) (@guaranteed T) -> ()
+///       destroy_value %arg : $T
+///       debug_value %addr : $*T, expr op_deref
+///
+/// Example #3: Handle control flow.
+///
+///     bb0(%arg : @owned $T):
+///       cond_br %_, bb1, bb2
+///     bb1:
+///       br bb3
+///     bb2:
+///       %copy = copy_value %arg : $T
+///       %_ = apply %_(%copy) : $@convention(thin) (@guaranteed T) -> ()
+///       destroy_value %copy : $T
+///       br bb3
+///     bb3:
+///       destroy_value %arg : $T
+///
+/// Will be transformed to:
+///
+///     bb0(%arg : @owned $T):
+///       cond_br %_, bb1, bb2
+///     bb1:
+///       destroy_value %arg : $T
+///       br bb3
+///     bb2:
+///       %_ = apply %_(%arg) : $@convention(thin) (@guaranteed T) -> ()
+///       destroy_value %arg : $T
+///       br bb3
+///     bb2:
+///       // The original destroy is deleted.
+///
+/// Pass Requirements:
+///
+///   This utility invalidates instructions but both uses and preserves
+///   NonLocalAccessBlockAnalysis.
+///
+///   The use-def walks in this utility, e.g. getCanonicalCopiedDef, assume no
+///   cycles in the data flow graph without a phi.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SILOPTIMIZER_UTILS_CANONICALOSSALIFETIME_H
+#define SWIFT_SILOPTIMIZER_UTILS_CANONICALOSSALIFETIME_H
+
+#include "swift/Basic/SmallPtrSetVector.h"
+#include "swift/SIL/PrunedLiveness.h"
+#include "swift/SIL/SILInstruction.h"
+#include "swift/SILOptimizer/Analysis/DeadEndBlocksAnalysis.h"
+#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
+#include "swift/SILOptimizer/Analysis/NonLocalAccessBlockAnalysis.h"
+#include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/Statistic.h"
+
+namespace swift {
+
+class BasicCalleeAnalysis;
+
+extern llvm::Statistic NumCopiesAndMovesEliminated;
+extern llvm::Statistic NumCopiesGenerated;
+
+/// Insert a copy on this operand. Trace and update stats.
+void copyLiveUse(Operand *use, InstModCallbacks &instModCallbacks);
+
+/// Diagnose that the given value is a move only type for which \p use causes a
+/// need to copy the move only value.
+///
+/// copy on this operand. Trace and update stats.
+void diagnoseRequiredCopyOfMoveOnly(Operand *use,
+                                    InstModCallbacks &instModCallbacks);
+
+/// Information about consumes on the extended-lifetime boundary. Consuming uses
+/// within the lifetime are not included--they will consume a copy after
+/// rewriting. For borrowed def values, the consumes do not include the end of
+/// the borrow scope, rather the consumes transitively include consumes of any
+/// owned copies of the borrowed value.
+///
+/// This result remains valid during copy rewriting. The only instructions
+/// referenced it contains are consumes that cannot be deleted.
+class CanonicalOSSAConsumeInfo final {
+  /// Map blocks on the lifetime boundary to the last consuming instruction.
+  llvm::SmallDenseMap<SILBasicBlock *, SILInstruction *, 4> finalBlockConsumes;
+
+  /// The instructions on the availability boundary of the dead-end region where
+  /// this value is not consumed.
+  SmallPtrSet<SILInstruction *, 4> unreachableLifetimeEnds;
+
+public:
+  void clear() { finalBlockConsumes.clear(); }
+
+  bool empty() { return finalBlockConsumes.empty(); }
+
+  bool hasUnclaimedConsumes() const { return !finalBlockConsumes.empty(); }
+
+  void recordFinalConsume(SILInstruction *inst) {
+    assert(!finalBlockConsumes.count(inst->getParent()));
+    finalBlockConsumes[inst->getParent()] = inst;
+  }
+
+  // Return true if this instruction is marked as a final consume point of the
+  // current def's live range. A consuming instruction can only be claimed once
+  // because instructions like `tuple` can consume the same value via multiple
+  // operands.
+  bool claimConsume(SILInstruction *inst) {
+    auto destroyPos = finalBlockConsumes.find(inst->getParent());
+    if (destroyPos != finalBlockConsumes.end() && destroyPos->second == inst) {
+      finalBlockConsumes.erase(destroyPos);
+      return true;
+    }
+    return false;
+  }
+
+  void recordUnreachableLifetimeEnd(SILInstruction *inst) {
+    unreachableLifetimeEnds.insert(inst);
+  }
+
+  bool isUnreachableLifetimeEnd(SILInstruction *inst) {
+    return unreachableLifetimeEnds.contains(inst);
+  }
+
+  CanonicalOSSAConsumeInfo() {}
+  CanonicalOSSAConsumeInfo(CanonicalOSSAConsumeInfo const &) = delete;
+  CanonicalOSSAConsumeInfo &
+  operator=(CanonicalOSSAConsumeInfo const &) = delete;
+  SWIFT_ASSERT_ONLY_DECL(void dump() const LLVM_ATTRIBUTE_USED);
+};
+
+enum PruneDebugInsts_t : bool {
+  DontPruneDebugInsts = false,
+  PruneDebugInsts = true,
+};
+
+enum MaximizeLifetime_t : bool {
+  DontMaximizeLifetime = false,
+  MaximizeLifetime = true,
+};
+
+/// Canonicalize OSSA lifetimes.
+///
+/// Allows the allocation of analysis state to be reused across calls to
+/// canonicalizeValueLifetime().
+///
+/// TODO: Move all the private per-definition members into an implementation
+/// class in the .cpp file.
+class OSSACanonicalizeOwned final {
+public:
+  /// Find the original definition of a potentially copied value. \p copiedValue
+  /// must be an owned value. It is usually a copy but may also be a destroy.
+  ///
+  /// This single helper specifies the root of an owned extended lifetime. Owned
+  /// extended lifetimes may not overlap. This ensures that canonicalization can
+  /// run as a utility without invalidating instruction worklists in the client,
+  /// as long as the client works on each canonical def independently.
+  ///
+  /// If the source of a copy is guaranteed, then the copy itself is the root of
+  /// an owned extended lifetime. Note that it will also be part of a borrowed
+  /// extended lifetime, which will be canonicalized separately by
+  /// OSSACanonicalizeGuaranteed.
+  ///
+  /// This use-def walk must be consistent with the def-use walks performed
+  /// within the canonicalizeValueLifetime() and canonicalizeBorrowScopes()
+  /// implementations.
+  static SILValue getCanonicalCopiedDef(SILValue v) {
+    while (auto *copy = dyn_cast<CopyValueInst>(v)) {
+      auto def = copy->getOperand();
+      if (def->getOwnershipKind() != OwnershipKind::Owned) {
+        // This guaranteed value cannot be handled, treat the copy as an owned
+        // live range def instead.
+        return copy;
+      }
+      v = def;
+    }
+    return v;
+  }
+
+private:
+  /// If true, then debug_value instructions outside of non-debug
+  /// liveness may be pruned during canonicalization.
+  const PruneDebugInsts_t pruneDebugMode;
+
+  /// If true, lifetimes will not be shortened except when necessary to avoid
+  /// copies.
+  const MaximizeLifetime_t maximizeLifetime;
+
+  SILFunction *function;
+
+  // If present, will be used to ensure that the lifetime is not shortened to
+  // end inside an access scope which it previously enclosed.  (Note that ending
+  // before such an access scope is fine regardless.)
+  //
+  // For details, see extendLivenessThroughOverlappingAccess.
+  NonLocalAccessBlockAnalysis *accessBlockAnalysis;
+  // Lazily initialize accessBlocks only when
+  // extendLivenessThroughOverlappingAccess is invoked.
+  NonLocalAccessBlocks *accessBlocks = nullptr;
+
+  DeadEndBlocksAnalysis *deadEndBlocksAnalysis;
+
+  DominanceInfo *domTree = nullptr;
+
+  BasicCalleeAnalysis *calleeAnalysis;
+
+  InstructionDeleter &deleter;
+
+  /// The SILValue to canonicalize.
+  SILValue currentDef;
+
+  /// Instructions beyond which liveness is not extended by destroy uses.
+  ArrayRef<SILInstruction *> explicitLifetimeEnds;
+
+  /// Original points in the CFG where the current value's lifetime is consumed
+  /// or destroyed.  Each block either contains a consuming instruction (e.g.
+  /// `destroy_value`) or is on the availability boundary of the value in a
+  /// dead-end region (e.g. `unreachable`).
+  ///
+  /// For guaranteed values it remains empty. A backward walk from these blocks
+  /// must discover all uses on paths that lead to a return or throw.
+  ///
+  /// These blocks are not necessarily in the pruned live blocks since
+  /// pruned liveness does not consider destroy_values.
+  llvm::SmallSetVector<SILBasicBlock *, 8> consumingBlocks;
+
+  /// Record all interesting debug_value instructions here rather then treating
+  /// them like a normal use. An interesting debug_value is one that may lie
+  /// outside the pruned liveness at the time it is discovered.
+  llvm::SmallPtrSet<DebugValueInst *, 8> debugValues;
+
+  struct Def {
+    enum Kind {
+      Root,
+      Copy,
+      BorrowedFrom,
+      Reborrow,
+    };
+    const Kind kind;
+    const SILValue value;
+    static Def root(SILValue value) { return {Root, value}; }
+    static Def copy(CopyValueInst *cvi) { return {Copy, cvi}; }
+    static Def borrowedFrom(BorrowedFromInst *bfi) {
+      return {BorrowedFrom, bfi};
+    }
+    static Def reborrow(SILArgument *argument) { return {Reborrow, argument}; }
+
+  private:
+    Def(Kind kind, SILValue value) : kind(kind), value(value) {}
+  };
+
+  /// The defs derived from currentDef whose uses are added to liveness.
+  SmallVector<Def, 8> discoveredDefs;
+
+  /// The blocks that were discovered by PrunedLiveness.
+  SmallVector<SILBasicBlock *, 32> discoveredBlocks;
+
+  /// Pruned liveness for the extended live range including copies. For this
+  /// purpose, only consuming instructions are considered "lifetime
+  /// ending". end_borrows do not end a liverange that may include owned copies.
+  BitfieldRef<SSAPrunedLiveness> liveness;
+
+  /// The destroys of the value.  These are not uses, but need to be recorded so
+  /// that we know when the last use in a consuming block is (without having to
+  /// repeatedly do use-def walks from destroys).
+  SmallPtrSetVector<SILInstruction *, 8> destroys;
+
+  /// Information about consuming instructions discovered in this canonical OSSA
+  /// lifetime.
+  CanonicalOSSAConsumeInfo consumes;
+
+public:
+  /// When rewriting destroys, is this an instruction which destroys should not
+  /// be hoisted over to avoid churn and infinite looping.
+  static bool ignoredByDestroyHoisting(SILInstructionKind kind) {
+    switch (kind) {
+    case SILInstructionKind::DebugValueInst:
+    case SILInstructionKind::DestroyValueInst:
+    case SILInstructionKind::CopyValueInst:
+    case SILInstructionKind::BeginBorrowInst:
+    case SILInstructionKind::EndBorrowInst:
+    case SILInstructionKind::FunctionRefInst:
+    case SILInstructionKind::EnumInst:
+    case SILInstructionKind::StructInst:
+      return true;
+    default:
+      return false;
+    }
+  }
+
+  /// Stack-allocated liveness for a single SSA def.
+  struct LivenessState {
+    BitfieldRef<SSAPrunedLiveness>::StackState state;
+
+    LivenessState(OSSACanonicalizeOwned &parent, SILValue def,
+                  ArrayRef<SILInstruction *> lexicalLifetimeEnds)
+        : state(parent.liveness, def->getFunction()) {
+      parent.initializeLiveness(def, lexicalLifetimeEnds);
+    }
+  };
+
+  OSSACanonicalizeOwned(
+      PruneDebugInsts_t pruneDebugMode, MaximizeLifetime_t maximizeLifetime,
+      SILFunction *function, NonLocalAccessBlockAnalysis *accessBlockAnalysis,
+      DeadEndBlocksAnalysis *deadEndBlocksAnalysis, DominanceInfo *domTree,
+      BasicCalleeAnalysis *calleeAnalysis, InstructionDeleter &deleter)
+      : pruneDebugMode(pruneDebugMode), maximizeLifetime(maximizeLifetime),
+        function(function), accessBlockAnalysis(accessBlockAnalysis),
+        deadEndBlocksAnalysis(deadEndBlocksAnalysis), domTree(domTree),
+        calleeAnalysis(calleeAnalysis), deleter(deleter) {}
+
+  SILValue getCurrentDef() const { return currentDef; }
+
+  void initializeLiveness(SILValue def,
+                          ArrayRef<SILInstruction *> lexicalLifetimeEnds) {
+    assert(consumingBlocks.empty() && debugValues.empty());
+    clear();
+
+    currentDef = def;
+    explicitLifetimeEnds = lexicalLifetimeEnds;
+
+    liveness->initializeDiscoveredBlocks(&discoveredBlocks);
+    liveness->initializeDef(getCurrentDef());
+  }
+
+  void clear() {
+    // Clear the access blocks analysis pointer in case the client invalidates
+    // the analysis.  If the client did, the analysis will be recomputed in
+    // extendLivenessThroughOverlappingAccess; if it didn't, the analysis
+    // pointer will just be set back to its old value when the analysis' cache
+    // is consulted in extendLivenessThroughOverlappingAccess.
+    accessBlocks = nullptr;
+
+    consumingBlocks.clear();
+    debugValues.clear();
+    discoveredBlocks.clear();
+    consumes.clear();
+    destroys.clear();
+  }
+
+  /// Top-Level API: rewrites copies and destroys within \p def's extended
+  /// lifetime.
+  ///
+  /// For lexical values, canonicalization respects deinit barriers, introducing
+  /// copies as needed to maintain lifetimes beyond final consuming uses to the
+  /// original lexical lifetime end.  When a lexical value is explicitly
+  /// consumed (via the `consume` keyword), however, the lifetime does not
+  /// extend to original destroys beyond that consume--the value must be dead
+  /// after the corresponding marker instructions (`move_value`); to support
+  /// this shortening, the marker instructions must be provided as \p
+  /// lexicalLifetimeEnds. When provided, deinit barriers will be respected
+  /// except to the extent doing so would result in the value being live after
+  /// the marker instructions.
+  ///
+  /// Return true if any change was made to \p def's extended lifetime. \p def
+  /// itself will not be deleted and no instructions outside of \p def's
+  /// extended lifetime will be affected (only copies and destroys are
+  /// rewritten).
+  ///
+  /// This only deletes instructions within \p def's extended lifetime. Use
+  /// InstructionDeleter::cleanUpDeadInstructions() to recursively delete dead
+  /// operands.
+  bool canonicalizeValueLifetime(
+      SILValue def, ArrayRef<SILInstruction *> lexicalLifetimeEnds = {});
+
+  /// Compute the liveness information for \p def. But do not do any rewriting
+  /// or computation of boundaries.
+  ///
+  /// The intention is that this is used if one wants to emit diagnostics using
+  /// the liveness information before doing any rewriting.
+  ///
+  /// Requires an active on-stack instance of LivenessState.
+  ///
+  ///     LivenessState livenessState(*this, def);
+  ///
+  bool computeLiveness();
+
+  /// Given the already computed liveness boundary for the given def, rewrite
+  /// copies of def as appropriate.
+  ///
+  /// Requires an active on-stack instance of LivenessState.
+  void rewriteLifetimes();
+
+  /// Return the pure original boundary just based off of liveness information
+  /// without maximizing or extending liveness.
+  ///
+  /// Requires an active on-stack instance of LivenessState.
+  void findOriginalBoundary(PrunedLivenessBoundary &resultingOriginalBoundary);
+
+  InstModCallbacks &getCallbacks() { return deleter.getCallbacks(); }
+
+  using IsInterestingUser = PrunedLiveness::IsInterestingUser;
+
+  /// Helper method that returns the isInterestingUser status of \p user in the
+  /// passed in Liveness.
+  ///
+  /// NOTE: Only call this after calling computeLivenessBoundary or the results
+  /// will not be initialized.
+  IsInterestingUser isInterestingUser(SILInstruction *user) const {
+    return liveness->isInterestingUser(user);
+  }
+
+  using LifetimeEndingUserRange = PrunedLiveness::LifetimeEndingUserRange;
+  LifetimeEndingUserRange getLifetimeEndingUsers() const {
+    return liveness->getLifetimeEndingUsers();
+  }
+
+  using NonLifetimeEndingUserRange = PrunedLiveness::NonLifetimeEndingUserRange;
+  NonLifetimeEndingUserRange getNonLifetimeEndingUsers() const {
+    return liveness->getNonLifetimeEndingUsers();
+  }
+
+  using UserRange = PrunedLiveness::ConstUserRange;
+  UserRange getUsers() const { return liveness->getAllUsers(); }
+
+private:
+  bool endingLifetimeAtExplicitEnds() const {
+    return explicitLifetimeEnds.size() > 0;
+  }
+
+  bool respectsDeadEnds() const {
+    // TODO: OSSACompleteLifetime: Once lifetimes are always complete, delete
+    //                               this method.
+    return !endingLifetimeAtExplicitEnds();
+  }
+
+  bool hasAnyDeadEnds() const {
+    return !deadEndBlocksAnalysis->get(function)->isEmpty();
+  }
+
+  bool respectsDeinitBarriers() const {
+    if (!currentDef->isLexical())
+      return false;
+    if (currentDef->getFunction()->forceEnableLexicalLifetimes())
+      return true;
+    auto &module = currentDef->getFunction()->getModule();
+    return module.getASTContext().SILOpts.supportsLexicalLifetimes(module);
+  }
+
+  void recordDebugValue(DebugValueInst *dvi) { debugValues.insert(dvi); }
+
+  void recordConsumingUse(Operand *use) { recordConsumingUser(use->getUser()); }
+  /// Record that the value is consumed at `user`.
+  ///
+  /// Either `user` is a consuming use (e.g. `destroy_value`) or it is the
+  /// terminator of a block on the availability boundary of the value in a
+  /// dead-end region (e.g. `unreachable`).
+  void recordConsumingUser(SILInstruction *user) {
+    consumingBlocks.insert(user->getParent());
+  }
+  void recordUnreachableLifetimeEnd(SILInstruction *user) {
+    recordConsumingUser(user);
+    consumes.recordUnreachableLifetimeEnd(user);
+  }
+  bool computeCanonicalLiveness();
+
+  bool endsAccessOverlappingPrunedBoundary(SILInstruction *inst);
+
+  void extendLivenessThroughOverlappingAccess();
+
+  void findExtendedBoundary(PrunedLivenessBoundary const &originalBoundary,
+                            PrunedLivenessBoundary &boundary);
+
+  void extendLivenessToDeadEnds();
+  void extendLexicalLivenessToDeadEnds();
+  void extendLivenessToDeinitBarriers();
+
+  void extendUnconsumedLiveness(PrunedLivenessBoundary const &boundary);
+  void visitExtendedUnconsumedBoundary(
+      ArrayRef<SILInstruction *> ends,
+      llvm::function_ref<void(SILInstruction *, PrunedLiveness::LifetimeEnding)>
+          visitor);
+
+  void insertDestroysOnBoundary(PrunedLivenessBoundary const &boundary,
+                                SmallVectorImpl<DestroyValueInst *> &destroys);
+
+  void rewriteCopies(SmallVectorImpl<DestroyValueInst *> const &destroys);
+};
+
+} // end namespace swift
+
+#endif
diff --git a/include/swift/SILOptimizer/Utils/OwnershipOptUtils.h b/include/swift/SILOptimizer/Utils/OwnershipOptUtils.h
index 772766301b1a1..412d1a0ef30f7 100644
--- a/include/swift/SILOptimizer/Utils/OwnershipOptUtils.h
+++ b/include/swift/SILOptimizer/Utils/OwnershipOptUtils.h
@@ -48,7 +48,7 @@ inline bool requiresOSSACleanup(SILValue v) {
 ///
 /// Precondition: lifetimeBoundary is a superset of ownedValue's current
 /// lifetime (therefore, none of the safety checks done during
-/// CanonicalizeOSSALifetime are needed here).
+/// OSSACanonicalizeOwned are needed here).
 void extendOwnedLifetime(SILValue ownedValue,
                          PrunedLivenessBoundary &lifetimeBoundary,
                          InstructionDeleter &deleter);
@@ -61,7 +61,7 @@ void extendOwnedLifetime(SILValue ownedValue,
 ///
 /// Precondition: guaranteedBoundary is a superset of beginBorrow's current
 /// scope (therefore, none of the safety checks done during
-/// CanonicalizeBorrowScope are needed here).
+/// OSSACanonicalizeGuaranteed are needed here).
 void extendLocalBorrow(BeginBorrowInst *beginBorrow,
                        PrunedLivenessBoundary &guaranteedBoundary,
                        InstructionDeleter &deleter);
@@ -79,11 +79,6 @@ void extendLocalBorrow(BeginBorrowInst *beginBorrow,
 /// newly created phis do not yet have a borrow scope.
 bool createBorrowScopeForPhiOperands(SILPhiArgument *newPhi);
 
-SILValue
-makeGuaranteedValueAvailable(SILValue value, SILInstruction *user,
-                             DeadEndBlocks &deBlocks,
-                             InstModCallbacks callbacks = InstModCallbacks());
-
 /// Compute the liveness boundary for a guaranteed value. Returns true if no
 /// uses are pointer escapes. If pointer escapes are present, the liveness
 /// boundary is still valid for all known uses.
diff --git a/include/swift/SILOptimizer/Utils/PartitionOpError.def b/include/swift/SILOptimizer/Utils/PartitionOpError.def
index 98253626e95ac..d4ef5b061dec6 100644
--- a/include/swift/SILOptimizer/Utils/PartitionOpError.def
+++ b/include/swift/SILOptimizer/Utils/PartitionOpError.def
@@ -52,6 +52,9 @@ PARTITION_OP_ERROR(InOutSendingNotInitializedAtExit)
 /// at end of function without being reinitialized with something disconnected.
 PARTITION_OP_ERROR(InOutSendingNotDisconnectedAtExit)
 
+/// This is emitted when a concrete inout sending parameter is returned.
+PARTITION_OP_ERROR(InOutSendingReturned)
+
 /// Used to signify an "unknown code pattern" has occured while performing
 /// dataflow.
 ///
diff --git a/include/swift/SILOptimizer/Utils/PartitionUtils.h b/include/swift/SILOptimizer/Utils/PartitionUtils.h
index 201441aaefc66..8c4d56280bd30 100644
--- a/include/swift/SILOptimizer/Utils/PartitionUtils.h
+++ b/include/swift/SILOptimizer/Utils/PartitionUtils.h
@@ -93,7 +93,7 @@ class RegionAnalysisValueMap;
 /// The representative value of the equivalence class that makes up a tracked
 /// value.
 ///
-/// We use a wrapper struct here so that we can inject "fake" actor isolated
+/// We use a wrapper struct here so that we can inject "fake" actor-isolated
 /// values into the regions of values that become merged into an actor by
 /// calling a function without a non-sendable result.
 class RepresentativeValue {
@@ -103,8 +103,8 @@ class RepresentativeValue {
 
   /// If this is set to a SILValue then it is the actual represented value. If
   /// it is set to a SILInstruction, then this is a "fake" representative value
-  /// used to inject actor isolatedness. The instruction stored is the
-  /// instruction that introduced the actor isolated-ness.
+  /// used to inject actor isolation. The instruction stored is the
+  /// instruction that introduced the actor isolation.
   InnerType value;
 
 public:
@@ -121,14 +121,14 @@ class RepresentativeValue {
       return;
     }
 
-    os << *value.get<SILValue>();
+    os << *cast<SILValue>(value);
   }
 
-  SILValue getValue() const { return value.get<SILValue>(); }
+  SILValue getValue() const { return cast<SILValue>(value); }
   SILValue maybeGetValue() const { return value.dyn_cast<SILValue>(); }
-  bool hasRegionIntroducingInst() const { return value.is<SILInstruction *>(); }
+  bool hasRegionIntroducingInst() const { return isa<SILInstruction *>(value); }
   SILInstruction *getActorRegionIntroducingInst() const {
-    return value.get<SILInstruction *>();
+    return cast<SILInstruction *>(value);
   }
 
   bool operator==(SILValue other) const {
@@ -282,7 +282,7 @@ class IsolationHistory::Node final
 
   /// Access the tail allocated buffer of additional element arguments.
   MutableArrayRef<Element> getAdditionalElementArgs() {
-    return {getTrailingObjects<Element>(), numAdditionalElements};
+    return getTrailingObjects(numAdditionalElements);
   }
 
   Node(Kind kind, Node *parent)
@@ -434,6 +434,16 @@ enum class PartitionOpKind : uint8_t {
   /// tryToTrackValue and SILIsolationInfo::get().
   AssignFresh,
 
+  /// Assign one value to a fresh region and then assign it to another value
+  /// that was also just assign fresh. Takes two parameters. The first is the
+  /// element to assign fresh and the second is the element to assign to.
+  ///
+  /// Used in combination with AssignFresh to initialize a chain of
+  /// values. Different from Assign since Assign allows for errors to
+  /// occur. This does not allow for any errors to be emitted since we are just
+  /// initializing a chain of values.
+  AssignFreshAssign,
+
   /// Merge the regions of two values, takes two args, both must be from
   /// non-sent regions.
   Merge,
@@ -483,39 +493,43 @@ enum class PartitionOpKind : uint8_t {
 class PartitionOp {
   using Element = PartitionPrimitives::Element;
 
-private:
-  PartitionOpKind opKind;
-  llvm::SmallVector<Element, 2> opArgs;
+public:
+  enum class Flag : uint8_t {
+    None,
+
+    /// This is a require of a non-Sendable base that we have a Sendable use
+    /// from. If the region was sent but at the sent point did not have any
+    /// element of the region that was captured by reference in a closure, we
+    /// can ignore the use.
+    RequireOfMutableBaseOfSendableValue,
+  };
+  using Options = OptionSet<Flag>;
 
+private:
   /// Record the SILInstruction that this PartitionOp was generated from, if
   /// generated during compilation from a SILBasicBlock
   PointerUnion<SILInstruction *, Operand *> source;
 
+  std::optional<Element> opArg1;
+  std::optional<Element> opArg2;
+
+  PartitionOpKind opKind;
+
+  Options options;
+
   // TODO: can the following declarations be merged?
   PartitionOp(PartitionOpKind opKind, Element arg1,
-              SILInstruction *sourceInst = nullptr)
-      : opKind(opKind), opArgs({arg1}), source(sourceInst) {
-    assert(((opKind != PartitionOpKind::Send &&
-             opKind != PartitionOpKind::UndoSend) ||
-            sourceInst) &&
-           "Send needs a sourceInst");
-  }
-
-  template <typename T>
-  PartitionOp(PartitionOpKind opKind, T collectionOfIndices,
-              SILInstruction *sourceInst = nullptr)
-      : opKind(opKind), opArgs(), source(sourceInst) {
+              SILInstruction *sourceInst = nullptr, Options options = {})
+      : source(sourceInst), opArg1(arg1), opKind(opKind), options(options) {
     assert(((opKind != PartitionOpKind::Send &&
              opKind != PartitionOpKind::UndoSend) ||
             sourceInst) &&
            "Send needs a sourceInst");
-    for (Element elt : collectionOfIndices) {
-      opArgs.push_back(elt);
-    }
   }
 
-  PartitionOp(PartitionOpKind opKind, Element arg1, Operand *sourceOperand)
-      : opKind(opKind), opArgs({arg1}), source(sourceOperand) {
+  PartitionOp(PartitionOpKind opKind, Element arg1, Operand *sourceOperand,
+              Options options = {})
+      : source(sourceOperand), opArg1(arg1), opKind(opKind), options(options) {
     assert(((opKind != PartitionOpKind::Send &&
              opKind != PartitionOpKind::UndoSend) ||
             bool(sourceOperand)) &&
@@ -523,8 +537,9 @@ class PartitionOp {
   }
 
   PartitionOp(PartitionOpKind opKind, Element arg1, Element arg2,
-              SILInstruction *sourceInst = nullptr)
-      : opKind(opKind), opArgs({arg1, arg2}), source(sourceInst) {
+              SILInstruction *sourceInst = nullptr, Options options = {})
+      : source(sourceInst), opArg1(arg1), opArg2(arg2), opKind(opKind),
+        options(options) {
     assert(((opKind != PartitionOpKind::Send &&
              opKind != PartitionOpKind::UndoSend) ||
             sourceInst) &&
@@ -532,15 +547,17 @@ class PartitionOp {
   }
 
   PartitionOp(PartitionOpKind opKind, Element arg1, Element arg2,
-              Operand *sourceOp = nullptr)
-      : opKind(opKind), opArgs({arg1, arg2}), source(sourceOp) {
+              Operand *sourceOp = nullptr, Options options = {})
+      : source(sourceOp), opArg1(arg1), opArg2(arg2), opKind(opKind),
+        options(options) {
     assert((opKind == PartitionOpKind::Assign ||
             opKind == PartitionOpKind::Merge) &&
            "Only supported for assign and merge");
   }
 
-  PartitionOp(PartitionOpKind opKind, SILInstruction *sourceInst)
-      : opKind(opKind), opArgs(), source(sourceInst) {}
+  PartitionOp(PartitionOpKind opKind, SILInstruction *sourceInst,
+              Options options = {})
+      : source(sourceInst), opKind(opKind), options(options) {}
 
   friend class Partition;
 
@@ -550,10 +567,19 @@ class PartitionOp {
     return PartitionOp(PartitionOpKind::Assign, destElt, srcElt, srcOperand);
   }
 
-  template <typename T>
-  static PartitionOp AssignFresh(T collection,
+  static PartitionOp AssignFresh(Element elt,
                                  SILInstruction *sourceInst = nullptr) {
-    return PartitionOp(PartitionOpKind::AssignFresh, collection, sourceInst);
+    return PartitionOp(PartitionOpKind::AssignFresh, elt, sourceInst);
+  }
+
+  /// Assign fresh \p elt and then assign it to \p srcElt.
+  ///
+  /// Used as part of emitting a sequence of AssignFresh that join the same
+  /// element.
+  static PartitionOp AssignFreshAssign(Element elt, Element srcElt,
+                                       SILInstruction *sourceInst = nullptr) {
+    return PartitionOp(PartitionOpKind::AssignFreshAssign, elt, srcElt,
+                       sourceInst);
   }
 
   static PartitionOp Send(Element tgt, Operand *sendingOp) {
@@ -570,9 +596,9 @@ class PartitionOp {
                        sourceOperand);
   }
 
-  static PartitionOp Require(Element tgt,
-                             SILInstruction *sourceInst = nullptr) {
-    return PartitionOp(PartitionOpKind::Require, tgt, sourceInst);
+  static PartitionOp Require(Element tgt, SILInstruction *sourceInst = nullptr,
+                             Options options = {}) {
+    return PartitionOp(PartitionOpKind::Require, tgt, sourceInst, options);
   }
 
   static PartitionOp UnknownPatternError(Element elt,
@@ -593,31 +619,60 @@ class PartitionOp {
   }
 
   bool operator==(const PartitionOp &other) const {
-    return opKind == other.opKind && opArgs == other.opArgs &&
-           source == other.source;
+    return opKind == other.opKind && opArg1 == other.opArg1 &&
+           opArg2 == other.opArg2 && source == other.source;
   };
 
   bool operator<(const PartitionOp &other) const {
     if (opKind != other.opKind)
       return opKind < other.opKind;
-    if (opArgs != other.opArgs)
-      return opArgs < other.opArgs;
+
+    if (opArg1 != other.opArg1) {
+      // null < non-null always.
+      if (!opArg1.has_value() && other.opArg1.has_value())
+        return true;
+      // non-null >= null always.
+      if (opArg1.has_value() && !other.opArg1.has_value())
+        return false;
+      return *opArg1 < other.opArg1.has_value();
+    }
+
+    if (opArg2 != other.opArg2) {
+      // null < non-null always.
+      if (!opArg2.has_value() && other.opArg2.has_value())
+        return true;
+      // non-null >= null always.
+      if (opArg2.has_value() && !other.opArg2.has_value())
+        return false;
+      return *opArg2 < other.opArg2.has_value();
+    }
+
     return source < other.source;
   }
 
   PartitionOpKind getKind() const { return opKind; }
 
-  ArrayRef<Element> getOpArgs() const { return opArgs; }
+  Element getOpArg1() const { return opArg1.value(); }
+  Element getOpArg2() const { return opArg2.value(); }
+
+  Options getOptions() const { return options; }
+
+  void getOpArgs(SmallVectorImpl<Element> &args) const {
+    if (opArg1.has_value())
+      args.push_back(*opArg1);
+    if (opArg2.has_value())
+      args.push_back(*opArg2);
+  }
 
   SILInstruction *getSourceInst() const {
-    if (source.is<Operand *>())
-      return source.get<Operand *>()->getUser();
-    return source.get<SILInstruction *>();
+    if (isa<Operand *>(source))
+      return cast<Operand *>(source)->getUser();
+    return cast<SILInstruction *>(source);
   }
 
-  bool hasSourceInst() const { return source.is<SILInstruction *>(); }
+  bool hasSourceInst() const { return isa<SILInstruction *>(source); }
 
-  Operand *getSourceOp() const { return source.get<Operand *>(); }
+  Operand *getSourceOp() const { return cast<Operand *>(source); }
 
   SILLocation getSourceLoc() const { return getSourceInst()->getLoc(); }
 
@@ -960,6 +1015,9 @@ class Partition {
 
 /// Swift style enum we use to decouple and reduce boilerplate in between the
 /// diagnostic and non-diagnostic part of the infrastructure.
+///
+/// NOTE: This is a noncopyable type so that we can store Partitions in these
+/// errors without copying them all over the place.
 class PartitionOpError {
 public:
   using Element = PartitionPrimitives::Element;
@@ -974,6 +1032,9 @@ class PartitionOpError {
     const PartitionOp *op;
 
     UnknownCodePatternError(const PartitionOp &op) : op(&op) {}
+    UnknownCodePatternError(UnknownCodePatternError &&other) = default;
+    UnknownCodePatternError &
+    operator=(UnknownCodePatternError &&other) = default;
 
     void print(llvm::raw_ostream &os, RegionAnalysisValueMap &valueMap) const;
 
@@ -991,6 +1052,9 @@ class PartitionOpError {
                            Operand *sendingOp)
         : op(&op), sentElement(elt), sendingOp(sendingOp) {}
 
+    LocalUseAfterSendError(LocalUseAfterSendError &&other) = default;
+    LocalUseAfterSendError &operator=(LocalUseAfterSendError &&other) = default;
+
     void print(llvm::raw_ostream &os, RegionAnalysisValueMap &valueMap) const;
 
     SWIFT_DEBUG_DUMPER(dump(RegionAnalysisValueMap &valueMap)) {
@@ -1008,6 +1072,9 @@ class PartitionOpError {
         : op(&op), sentElement(sentElement),
           isolationRegionInfo(isolationRegionInfo) {}
 
+    SentNeverSendableError(SentNeverSendableError &&other) = default;
+    SentNeverSendableError &operator=(SentNeverSendableError &&other) = default;
+
     void print(llvm::raw_ostream &os, RegionAnalysisValueMap &valueMap) const;
 
     SWIFT_DEBUG_DUMPER(dump(RegionAnalysisValueMap &valueMap)) {
@@ -1031,6 +1098,11 @@ class PartitionOpError {
           srcElement(srcElement), srcValue(srcValue),
           srcIsolationRegionInfo(srcIsolationRegionInfo) {}
 
+    AssignNeverSendableIntoSendingResultError(
+        AssignNeverSendableIntoSendingResultError &&other) = default;
+    AssignNeverSendableIntoSendingResultError &
+    operator=(AssignNeverSendableIntoSendingResultError &&other) = default;
+
     void print(llvm::raw_ostream &os, RegionAnalysisValueMap &valueMap) const;
 
     SWIFT_DEBUG_DUMPER(dump(RegionAnalysisValueMap &valueMap)) {
@@ -1047,6 +1119,11 @@ class PartitionOpError {
                                           Operand *sendingOp)
         : op(&op), sentElement(elt), sendingOp(sendingOp) {}
 
+    InOutSendingNotInitializedAtExitError(
+        InOutSendingNotInitializedAtExitError &&other) = default;
+    InOutSendingNotInitializedAtExitError &
+    operator=(InOutSendingNotInitializedAtExitError &&other) = default;
+
     void print(llvm::raw_ostream &os, RegionAnalysisValueMap &valueMap) const;
 
     SWIFT_DEBUG_DUMPER(dump(RegionAnalysisValueMap &valueMap)) {
@@ -1064,6 +1141,49 @@ class PartitionOpError {
         SILDynamicMergedIsolationInfo isolation)
         : op(&op), inoutSendingElement(elt), isolationInfo(isolation) {}
 
+    InOutSendingNotDisconnectedAtExitError(
+        InOutSendingNotDisconnectedAtExitError &&other) = default;
+    InOutSendingNotDisconnectedAtExitError &
+    operator=(InOutSendingNotDisconnectedAtExitError &&other) = default;
+
+    void print(llvm::raw_ostream &os, RegionAnalysisValueMap &valueMap) const;
+
+    SWIFT_DEBUG_DUMPER(dump(RegionAnalysisValueMap &valueMap)) {
+      print(llvm::dbgs(), valueMap);
+    }
+  };
+
+  struct InOutSendingReturnedError {
+    const PartitionOp *op;
+
+    /// The 'inout sending' parameter that caused the error to be emitted.
+    Element inoutSendingElement;
+
+    /// The actual returned value. If we return the 'inout sending' parameter
+    /// then this will equal inoutSendingElement.
+    Element returnedValue;
+
+    /// If we are actor isolated due to being in the same region as the out
+    /// parameter of a actor isolated method... this is that actor isolation.
+    SILDynamicMergedIsolationInfo isolationInfo;
+
+    InOutSendingReturnedError(const PartitionOp &op,
+                              Element inoutSendingElement,
+                              Element returnedValue,
+                              SILDynamicMergedIsolationInfo isolationInfo = {})
+        : op(&op), inoutSendingElement(inoutSendingElement),
+          returnedValue(returnedValue), isolationInfo(isolationInfo) {}
+
+    InOutSendingReturnedError(const PartitionOp &op,
+                              Element inoutSendingElement,
+                              SILDynamicMergedIsolationInfo isolationInfo = {})
+        : InOutSendingReturnedError(op, inoutSendingElement,
+                                    inoutSendingElement, isolationInfo) {}
+
+    InOutSendingReturnedError(InOutSendingReturnedError &&other) = default;
+    InOutSendingReturnedError &
+    operator=(InOutSendingReturnedError &&other) = default;
+
     void print(llvm::raw_ostream &os, RegionAnalysisValueMap &valueMap) const;
 
     SWIFT_DEBUG_DUMPER(dump(RegionAnalysisValueMap &valueMap)) {
@@ -1080,6 +1200,11 @@ class PartitionOpError {
                                             Element returnValue)
         : op(&op), returnValueElement(returnValue) {}
 
+    NonSendableIsolationCrossingResultError(
+        NonSendableIsolationCrossingResultError &&other) = default;
+    NonSendableIsolationCrossingResultError &
+    operator=(NonSendableIsolationCrossingResultError &&other) = default;
+
     void print(llvm::raw_ostream &os, RegionAnalysisValueMap &valueMap) const;
 
     SWIFT_DEBUG_DUMPER(dump(RegionAnalysisValueMap &valueMap)) {
@@ -1088,12 +1213,14 @@ class PartitionOpError {
   };
 
 #define PARTITION_OP_ERROR(NAME)                                               \
-  static_assert(std::is_copy_constructible_v<NAME##Error>,                     \
-                #NAME " must be copy constructable");
-#include "PartitionOpError.def"
-#define PARTITION_OP_ERROR(NAME)                                               \
-  static_assert(std::is_copy_assignable_v<NAME##Error>,                        \
-                #NAME " must be copy assignable");
+  static_assert(!std::is_copy_constructible_v<NAME##Error>,                    \
+                #NAME " must not be copy constructable");                      \
+  static_assert(std::is_move_constructible_v<NAME##Error>,                     \
+                #NAME " must be move constructable");                          \
+  static_assert(!std::is_copy_assignable_v<NAME##Error>,                       \
+                #NAME " must not be copy assignable");                         \
+  static_assert(std::is_move_assignable_v<NAME##Error>,                        \
+                #NAME " must be move assignable");
 #include "PartitionOpError.def"
 
 private:
@@ -1107,11 +1234,12 @@ class PartitionOpError {
 
 public:
 #define PARTITION_OP_ERROR(NAME)                                               \
-  PartitionOpError(NAME##Error error) : kind(Kind::NAME), data(error) {}
+  PartitionOpError(NAME##Error &&error)                                        \
+      : kind(Kind::NAME), data(std::move(error)) {}
 #include "PartitionOpError.def"
 
-  PartitionOpError(const PartitionOpError &error)
-      : kind(error.kind), data(error.data) {
+  PartitionOpError(PartitionOpError &&error)
+      : kind(error.kind), data(std::move(error.data)) {
     switch (getKind()) {
 #define PARTITION_OP_ERROR(NAME)                                               \
   case NAME:                                                                   \
@@ -1122,9 +1250,9 @@ class PartitionOpError {
     }
   }
 
-  PartitionOpError &operator=(const PartitionOpError &error) {
+  PartitionOpError &operator=(PartitionOpError &&error) {
     kind = error.kind;
-    data = error.data;
+    data = std::move(error.data);
 
     switch (getKind()) {
 #define PARTITION_OP_ERROR(NAME)                                               \
@@ -1143,7 +1271,7 @@ class PartitionOpError {
     switch (getKind()) {
 #define PARTITION_OP_ERROR(NAME)                                               \
   case NAME:                                                                   \
-    return get##NAME##Error().print(os, valueMap);
+    return std::get<NAME##Error>(data).print(os, valueMap);
 #include "PartitionOpError.def"
     }
     llvm_unreachable("Covered switch isn't covered?!");
@@ -1154,9 +1282,9 @@ class PartitionOpError {
   }
 
 #define PARTITION_OP_ERROR(NAME)                                               \
-  NAME##Error get##NAME##Error() const {                                       \
+  NAME##Error get##NAME##Error() && {                                          \
     assert(getKind() == Kind::NAME);                                           \
-    return std::get<NAME##Error>(data);                                        \
+    return std::get<NAME##Error>(std::move(data));                             \
   }
 #include "PartitionOpError.def"
 };
@@ -1199,7 +1327,9 @@ struct PartitionOpEvaluator {
     return asImpl().shouldEmitVerboseLogging();
   }
 
-  void handleError(PartitionOpError error) { asImpl().handleError(error); }
+  void handleError(PartitionOpError &&error) {
+    asImpl().handleError(std::move(error));
+  }
 
   /// Call isActorDerived on our CRTP subclass.
   bool isActorDerived(Element elt) const {
@@ -1226,8 +1356,9 @@ struct PartitionOpEvaluator {
             isolationRegionInfo->merge(getIsolationRegionInfo(pair.first));
         if (!isolationRegionInfo)
           return {};
-        if (sourceOp)
+        if (sourceOp) {
           isClosureCapturedElt |= isClosureCaptured(pair.first, sourceOp);
+        }
       }
     }
 
@@ -1241,6 +1372,42 @@ struct PartitionOpEvaluator {
     return SILDynamicMergedIsolationInfo();
   }
 
+  /// If \p region is not disconnected only because of an out parameter, return
+  /// that out parameter. We do not care about other non-disconnected parameters
+  /// since we always want to prefer the return error.
+  SILValue findNonDisconnectedOutParameterInRegion(Region region) const {
+    for (const auto &pair : p.range()) {
+      if (pair.second != region)
+        continue;
+      auto info = getIsolationRegionInfo(pair.first);
+
+      // If we do not have any isolation info, then something bad
+      // happened. Return SILValue().
+      if (!info)
+        return {};
+
+      // If we have something that is disconnected... continue. We do not care
+      // about this.
+      if (info.isDisconnected())
+        continue;
+
+      // See if we ahve an indirect out parameter...
+      if (auto value = asImpl().getIndirectOutParameter(pair.first)) {
+        return value;
+      }
+
+      // If this was not an out parameter, return {}.
+      return {};
+    }
+
+    // After going over our loop, if result is not SILValue(), then we found
+    // that our region is not disconnected due only to a single 'indirect out'
+    // parameter. If SILValue() then we had all disconnected values. If we found
+    // multiple non-disconnected things, we would have bailed earlier in the
+    // loop itself.
+    return SILValue();
+  }
+
   bool isTaskIsolatedDerived(Element elt) const {
     return asImpl().isTaskIsolatedDerived(elt);
   }
@@ -1287,6 +1454,39 @@ struct PartitionOpEvaluator {
     return asImpl().getRepresentativeValue(element);
   }
 
+  /// See if we are assigning an a non-disconnected value into a 'out
+  /// sending' parameter. In such a case, we emit a diagnostic.
+  ///
+  /// Helper used to handle assignment into sending results in the context of
+  /// assigns or merges.
+  void handleAssignNonDisconnectedIntoSendingResult(const PartitionOp &op) {
+    if (!doesParentFunctionHaveSendingResult(op))
+      return;
+
+    auto instance = getRepresentativeValue(op.getOpArg1());
+    if (!instance)
+      return;
+
+    auto *fArg =
+        dyn_cast_or_null<SILFunctionArgument>(instance.maybeGetValue());
+    if (!fArg || !fArg->getArgumentConvention().isIndirectOutParameter())
+      return;
+
+    auto staticRegionIsolation = getIsolationRegionInfo(op.getOpArg2());
+    Region srcRegion = p.getRegion(op.getOpArg2());
+    auto dynamicRegionIsolation = getIsolationRegionInfo(srcRegion);
+
+    // We can unconditionally getValue here since we can never
+    // assign an actor introducing inst.
+    auto rep = getRepresentativeValue(op.getOpArg2()).getValue();
+    if (dynamicRegionIsolation.isDisconnected() ||
+        staticRegionIsolation.isUnsafeNonIsolated())
+      return;
+
+    handleError(AssignNeverSendableIntoSendingResultError(
+        op, op.getOpArg1(), fArg, op.getOpArg2(), rep, dynamicRegionIsolation));
+  }
+
   /// Apply \p op to the partition op.
   void apply(const PartitionOp &op) {
     if (shouldEmitVerboseLogging()) {
@@ -1311,51 +1511,22 @@ struct PartitionOpEvaluator {
 
     switch (op.getKind()) {
     case PartitionOpKind::Assign: {
-      assert(op.getOpArgs().size() == 2 &&
-             "Assign PartitionOp should be passed 2 arguments");
-      assert(p.isTrackingElement(op.getOpArgs()[1]) &&
+      assert(p.isTrackingElement(op.getOpArg2()) &&
              "Assign PartitionOp's source argument should be already tracked");
 
-      // See if we are assigning an a non-disconnected value into a 'out
-      // sending' parameter. In such a case, we emit a diagnostic.
-      if (doesParentFunctionHaveSendingResult(op)) {
-        if (auto instance = getRepresentativeValue(op.getOpArgs()[0])) {
-          if (auto value = instance.maybeGetValue()) {
-            if (auto *fArg = dyn_cast<SILFunctionArgument>(value)) {
-              if (fArg->getArgumentConvention().isIndirectOutParameter()) {
-                auto staticRegionIsolation =
-                    getIsolationRegionInfo(op.getOpArgs()[1]);
-                Region srcRegion = p.getRegion(op.getOpArgs()[1]);
-                auto dynamicRegionIsolation = getIsolationRegionInfo(srcRegion);
-
-                // We can unconditionally getValue here since we can never
-                // assign an actor introducing inst.
-                auto rep = getRepresentativeValue(op.getOpArgs()[1]).getValue();
-                if (!dynamicRegionIsolation.isDisconnected() &&
-                    !staticRegionIsolation.isUnsafeNonIsolated()) {
-                  handleError(AssignNeverSendableIntoSendingResultError(
-                      op, op.getOpArgs()[0], fArg, op.getOpArgs()[1], rep,
-                      dynamicRegionIsolation));
-                }
-              }
-            }
-          }
-        }
-      }
+      // First emit any errors if we are assigning a non-disconnected thing into
+      // a sending result.
+      handleAssignNonDisconnectedIntoSendingResult(op);
 
-      p.assignElement(op.getOpArgs()[0], op.getOpArgs()[1]);
+      // Then perform the actual assignment.
+      //
+      // NOTE: This does not emit any errors on purpose. We rely on requires and
+      // other instructions to emit errors.
+      p.assignElement(op.getOpArg1(), op.getOpArg2());
       return;
     }
     case PartitionOpKind::AssignFresh: {
-      auto arrayRef = op.getOpArgs();
-
-      Element front = arrayRef.front();
-      p.trackNewElement(front);
-      arrayRef = arrayRef.drop_front();
-      for (auto x : arrayRef) {
-        p.trackNewElement(x);
-        p.assignElement(x, front);
-      }
+      p.trackNewElement(op.getOpArg1());
       return;
     }
     case PartitionOpKind::Send: {
@@ -1364,14 +1535,12 @@ struct PartitionOpEvaluator {
       // ensures that if we pass the same argument multiple times to the same
       // sending function as weakly sent arguments, we do not get an
       // error.
-      assert(op.getOpArgs().size() == 1 &&
-             "Send PartitionOp should be passed 1 argument");
-      assert(p.isTrackingElement(op.getOpArgs()[0]) &&
+      assert(p.isTrackingElement(op.getOpArg1()) &&
              "Send PartitionOp's argument should already be tracked");
 
       // Before we do any further work, see if we have a nonisolated(unsafe)
       // element. In such a case, this is also not a real send point.
-      Element sentElement = op.getOpArgs()[0];
+      Element sentElement = op.getOpArg1();
       if (getIsolationRegionInfo(sentElement).isUnsafeNonIsolated()) {
         return;
       }
@@ -1380,7 +1549,7 @@ struct PartitionOpEvaluator {
       // isolation region info of everything else in our region. This is the
       // dynamic isolation region info found by the dataflow.
       Region sentRegion = p.getRegion(sentElement);
-      bool isClosureCapturedElt = false;
+      bool regionHasClosureCapturedElt = false;
       SILDynamicMergedIsolationInfo sentRegionIsolation;
 
       // TODO: Today we only return the first element in our region that has
@@ -1392,17 +1561,20 @@ struct PartitionOpEvaluator {
       if (!pairOpt) {
         return handleError(UnknownCodePatternError(op));
       }
-      std::tie(sentRegionIsolation, isClosureCapturedElt) = *pairOpt;
+      std::tie(sentRegionIsolation, regionHasClosureCapturedElt) = *pairOpt;
 
-      // If we merged anything, we need to handle an attempt to send a
-      // never-sent value unless our value has the same isolation info as our
-      // callee.
       auto calleeIsolationInfo = getIsolationInfo(op);
-      if (!(calleeIsolationInfo &&
-            sentRegionIsolation.hasSameIsolation(calleeIsolationInfo)) &&
-          !sentRegionIsolation.isDisconnected()) {
-        return handleSendNeverSentHelper(op, op.getOpArgs()[0],
-                                         sentRegionIsolation);
+
+      // If our callee and region are both actor isolated and part of the same
+      // isolation domain, do not treat this as a send.
+      if (calleeIsolationInfo.isActorIsolated() &&
+          sentRegionIsolation.hasSameIsolation(calleeIsolationInfo))
+        return;
+
+      // At this point, check if our sent value is not disconnected. If so, emit
+      // a sent never sendable helper.
+      if (sentRegionIsolation && !sentRegionIsolation.isDisconnected()) {
+        return handleSendNeverSentHelper(op, op.getOpArg1(), sentRegionIsolation);
       }
 
       // Next see if we are disconnected and have the same isolation. In such a
@@ -1417,9 +1589,9 @@ struct PartitionOpEvaluator {
           return;
       }
 
-      // Mark op.getOpArgs()[0] as sent.
+      // Mark op.getOpArg1() as sent.
       SendingOperandState &state = operandToStateMap.get(op.getSourceOp());
-      state.isClosureCaptured |= isClosureCapturedElt;
+      state.isClosureCaptured |= regionHasClosureCapturedElt;
       if (auto newInfo = state.isolationInfo.merge(sentRegionIsolation)) {
         state.isolationInfo = *newInfo;
       } else {
@@ -1428,85 +1600,61 @@ struct PartitionOpEvaluator {
       assert(state.isolationInfo && "Cannot have unknown");
       state.isolationHistory.pushCFGHistoryJoin(p.getIsolationHistory());
       auto *ptrSet = ptrSetFactory.get(op.getSourceOp());
-      p.markSent(op.getOpArgs()[0], ptrSet);
+      p.markSent(op.getOpArg1(), ptrSet);
       return;
     }
     case PartitionOpKind::UndoSend: {
-      assert(op.getOpArgs().size() == 1 &&
-             "UndoSend PartitionOp should be passed 1 argument");
-      assert(p.isTrackingElement(op.getOpArgs()[0]) &&
+      assert(p.isTrackingElement(op.getOpArg1()) &&
              "UndoSend PartitionOp's argument should already be tracked");
 
-      // Mark op.getOpArgs()[0] as not sent.
-      p.undoSend(op.getOpArgs()[0]);
+      // Mark op.getOpArg1() as not sent.
+      p.undoSend(op.getOpArg1());
       return;
     }
     case PartitionOpKind::Merge: {
-      assert(op.getOpArgs().size() == 2 &&
-             "Merge PartitionOp should be passed 2 arguments");
-      assert(p.isTrackingElement(op.getOpArgs()[0]) &&
-             p.isTrackingElement(op.getOpArgs()[1]) &&
+      assert(p.isTrackingElement(op.getOpArg1()) &&
+             p.isTrackingElement(op.getOpArg2()) &&
              "Merge PartitionOp's arguments should already be tracked");
 
-      // See if we are assigning an a non-disconnected value into a 'out
-      // sending' parameter. In such a case, we emit a diagnostic.
-      if (doesParentFunctionHaveSendingResult(op)) {
-        if (auto instance = getRepresentativeValue(op.getOpArgs()[0])) {
-          if (auto value = instance.maybeGetValue()) {
-            if (auto *fArg = dyn_cast<SILFunctionArgument>(value)) {
-              if (fArg->getArgumentConvention().isIndirectOutParameter()) {
-                auto staticRegionIsolation =
-                    getIsolationRegionInfo(op.getOpArgs()[1]);
-                Region srcRegion = p.getRegion(op.getOpArgs()[1]);
-                auto dynamicRegionIsolation = getIsolationRegionInfo(srcRegion);
-                // We can unconditionally getValue here since we can never
-                // assign an actor introducing inst.
-                auto rep = getRepresentativeValue(op.getOpArgs()[1]).getValue();
-                if (!dynamicRegionIsolation.isDisconnected() &&
-                    !staticRegionIsolation.isUnsafeNonIsolated()) {
-                  handleError(AssignNeverSendableIntoSendingResultError(
-                      op, op.getOpArgs()[0], fArg, op.getOpArgs()[1], rep,
-                      dynamicRegionIsolation));
-                }
-              }
-            }
-          }
-        }
-      }
+      // Emit an error if we are assigning a non-disconnected thing into a
+      // sending result.
+      handleAssignNonDisconnectedIntoSendingResult(op);
 
-      p.merge(op.getOpArgs()[0], op.getOpArgs()[1]);
+      // Then perform the actual merge.
+      //
+      // NOTE: This does not emit any errors on purpose. We rely on requires and
+      // other instructions to emit errors.
+      p.merge(op.getOpArg1(), op.getOpArg2());
       return;
     }
     case PartitionOpKind::Require:
-      assert(op.getOpArgs().size() == 1 &&
-             "Require PartitionOp should be passed 1 argument");
-      assert(p.isTrackingElement(op.getOpArgs()[0]) &&
+      assert(p.isTrackingElement(op.getOpArg1()) &&
              "Require PartitionOp's argument should already be tracked");
-      if (auto *sentOperandSet = p.getSentOperandSet(op.getOpArgs()[0])) {
+      if (auto *sentOperandSet = p.getSentOperandSet(op.getOpArg1())) {
         for (auto sentOperand : sentOperandSet->data()) {
-          handleLocalUseAfterSendHelper(op, op.getOpArgs()[0], sentOperand);
+          handleLocalUseAfterSendHelper(op, op.getOpArg1(), sentOperand);
         }
       }
       return;
     case PartitionOpKind::InOutSendingAtFunctionExit: {
-      assert(op.getOpArgs().size() == 1 &&
-             "Require PartitionOp should be passed 1 argument");
-      assert(p.isTrackingElement(op.getOpArgs()[0]) &&
+      assert(p.isTrackingElement(op.getOpArg1()) &&
              "Require PartitionOp's argument should already be tracked");
 
       // First check if the region of our 'inout sending' element has been
-      // sent. In that case, we emit a special use after free error.
-      if (auto *sentOperandSet = p.getSentOperandSet(op.getOpArgs()[0])) {
+      // sent. In that case, we emit a special use after free error so that the
+      // user knows that they need to reinitialize the 'inout sending'
+      // parameter.
+      if (auto *sentOperandSet = p.getSentOperandSet(op.getOpArg1())) {
         for (auto sentOperand : sentOperandSet->data()) {
-          handleError(InOutSendingNotInitializedAtExitError(
-              op, op.getOpArgs()[0], sentOperand));
+          handleError(InOutSendingNotInitializedAtExitError(op, op.getOpArg1(),
+                                                            sentOperand));
         }
         return;
       }
 
-      // If we were not sent, check if our region is actor isolated. If so,
+      // If we were not sent, check if our region is not disconnected. If so,
       // error since we need a disconnected value in the inout parameter.
-      Region inoutSendingRegion = p.getRegion(op.getOpArgs()[0]);
+      Region inoutSendingRegion = p.getRegion(op.getOpArg1());
       auto dynamicRegionIsolation = getIsolationRegionInfo(inoutSendingRegion);
 
       // If we failed to merge emit an unknown pattern error so we fail.
@@ -1515,28 +1663,101 @@ struct PartitionOpEvaluator {
         return;
       }
 
-      // Otherwise, emit the error if the dynamic region isolation is not
-      // disconnected.
+      auto handleDirectReturn = [&]() -> bool {
+        bool emittedDiagnostic = false;
+
+        // For each value we are returning...
+        for (auto value : op.getSourceInst()->getOperandValues()) {
+          // Find its element and check if that element is in the same region as
+          // our inout sending param...
+          auto elt = asImpl().getElement(value);
+          if (!elt || inoutSendingRegion != p.getRegion(*elt))
+            continue;
+
+          emittedDiagnostic = true;
+          // Then check if our element is the same as our inoutSendingParam. In
+          // that case, we emit a special error that only refers to the
+          // inoutSendingParam as one entity.
+          //
+          // NOTE: This is taking advantage of us looking through loads when
+          // determining element identity. When that changes, this code will
+          // need to be updated to look through loads.
+          if (*elt == op.getOpArg1()) {
+            handleError(InOutSendingReturnedError(op, op.getOpArg1(),
+                                                  dynamicRegionIsolation));
+            continue;
+          }
+
+          // Otherwise, we need to refer to a different value in the same region
+          // as the 'inout sending' parameter. Emit a special error. For that.
+          handleError(InOutSendingReturnedError(op, op.getOpArg1(), *elt,
+                                                dynamicRegionIsolation));
+        }
+
+        return emittedDiagnostic;
+      };
+
+      // Then check if our region isolated value is not disconnected...
       if (!dynamicRegionIsolation.isDisconnected()) {
+        // Before we emit the more general "inout sending" not disconnected at
+        // exit error... check if our dynamic region isolation is not
+        // disconnected since it is in the same region an out parameter. In that
+        // case we want to emit a special 'cannot return value' error.
+        if (auto outParam =
+                findNonDisconnectedOutParameterInRegion(inoutSendingRegion)) {
+          handleError(InOutSendingReturnedError(op, op.getOpArg1(),
+                                                getElement(outParam).value(),
+                                                dynamicRegionIsolation));
+          return;
+        }
+
+        // If we did not have an out parameter, see if we are returning a
+        // value that is in the region as our 'inout sending' parameter.
+        if (handleDirectReturn())
+          return;
+
+        // Otherwise, we emit the normal not disconnected at exit error.
         handleError(InOutSendingNotDisconnectedAtExitError(
-            op, op.getOpArgs()[0], dynamicRegionIsolation));
+            op, op.getOpArg1(), dynamicRegionIsolation));
+        return;
       }
+
+      // Ok, we have a disconnected value. We could still be returning a
+      // disconnected value in the same region as an 'inout sending'
+      // parameter. We cannot allow that since the caller considers 'inout
+      // sending' values to be in their own region on function return. So it
+      // would assume that it could potentially send the value in the 'inout
+      // sending' parameter and the return value to different isolation
+      // domains... allowing for races.
+
+      // Even though we are disconnected, see if our SILFunction has an actor
+      // isolation. In that case, we want to use that since the direct return
+      // value will be inferred in the caller to have that isolation.
+      if (auto isolation = SILIsolationInfo::getFunctionIsolation(
+              op.getSourceInst()->getFunction())) {
+        dynamicRegionIsolation = {isolation};
+      }
+
+      handleDirectReturn();
       return;
     }
     case PartitionOpKind::UnknownPatternError:
       // Begin tracking the specified element in case we have a later use.
-      p.trackNewElement(op.getOpArgs()[0]);
+      p.trackNewElement(op.getOpArg1());
 
       // Then emit an unknown code pattern error.
       return handleError(UnknownCodePatternError(op));
-    case PartitionOpKind::NonSendableIsolationCrossingResult:
-      // Grab the dynamic dataflow isolation information for our element's
-      // region.
-      Region region = p.getRegion(op.getOpArgs()[0]);
-
+    case PartitionOpKind::NonSendableIsolationCrossingResult: {
       // Then emit the error.
       return handleError(
-          NonSendableIsolationCrossingResultError(op, op.getOpArgs()[0]));
+          NonSendableIsolationCrossingResultError(op, op.getOpArg1()));
+    }
+    case PartitionOpKind::AssignFreshAssign:
+      assert(p.isTrackingElement(op.getOpArg2()) &&
+             "Source argument should be already tracked");
+      p.trackNewElement(op.getOpArg1());
+      p.assignElement(op.getOpArg1(), op.getOpArg2());
+      return;
     }
     llvm_unreachable("Covered switch isn't covered?!");
   }
@@ -1555,9 +1776,32 @@ struct PartitionOpEvaluator {
   }
 
 private:
-  bool isConvertFunctionFromSendableType(SILValue equivalenceClassRep) const {
+  /// To work around not having isolation in interface types, the type checker
+  /// inserts casts and other AST nodes that are used to enrich the AST with
+  /// isolation information. This results in Sendable functions being
+  /// wrapped/converted/etc in ways that hide the Sendability. This helper looks
+  /// through these conversions/wrappers/thunks to see if the original
+  /// underlying function is Sendable.
+  ///
+  /// The two ways this can happen is that we either get an actual function_ref
+  /// that is Sendable or we get a convert function with a Sendable operand.
+  bool isHiddenSendableFunctionType(SILValue equivalenceClassRep) const {
     SILValue valueToTest = equivalenceClassRep;
     while (true) {
+      if (auto *pai = dyn_cast<PartialApplyInst>(valueToTest)) {
+        if (auto *calleeFunction = pai->getCalleeFunction()) {
+          if (pai->getNumArguments() >= 1 &&
+              pai->getArgument(0)->getType().isFunction() &&
+              calleeFunction->isThunk()) {
+            valueToTest = pai->getArgument(0);
+            continue;
+          }
+
+          if (calleeFunction->getLoweredFunctionType()->isSendable())
+            return true;
+        }
+      }
+
       if (auto *i = dyn_cast<ThinToThickFunctionInst>(valueToTest)) {
         valueToTest = i->getOperand();
         continue;
@@ -1569,6 +1813,9 @@ struct PartitionOpEvaluator {
       break;
     }
 
+    if (auto *fn = dyn_cast<FunctionRefInst>(valueToTest))
+      return fn->getReferencedFunction()->getLoweredFunctionType()->isSendable();
+
     auto *cvi = dyn_cast<ConvertFunctionInst>(valueToTest);
     if (!cvi)
       return false;
@@ -1601,7 +1848,7 @@ struct PartitionOpEvaluator {
 
         // See if we have a convert function from a `@Sendable` type. In this
         // case, we want to squelch the error.
-        if (isConvertFunctionFromSendableType(equivalenceClassRep))
+        if (isHiddenSendableFunctionType(equivalenceClassRep))
           return;
       }
 
@@ -1646,7 +1893,7 @@ struct PartitionOpEvaluator {
 
         // See if we have a convert function from a `@Sendable` type. In this
         // case, we want to squelch the error.
-        if (isConvertFunctionFromSendableType(equivalenceClassRep))
+        if (isHiddenSendableFunctionType(equivalenceClassRep))
           return;
       }
     }
@@ -1685,8 +1932,16 @@ struct PartitionOpEvaluatorBaseImpl : PartitionOpEvaluator<Subclass> {
   /// isolated value.
   bool isTaskIsolatedDerived(Element elt) const { return false; }
 
+  /// If \p elt maps to a representative that is an indirect out parameter,
+  /// return that value.
+  SILValue getIndirectOutParameter(Element elt) const { return {}; }
+
+  /// If \p elt maps to a representative that is an 'inout sending' parameter
+  /// that returns that value.
+  SILValue getInOutSendingParameter(Element elt) const { return {}; }
+
   /// By default, do nothing upon error.
-  void handleError(PartitionOpError error) {}
+  void handleError(PartitionOpError &&error) {}
 
   /// Returns the information about \p elt's isolation that we ascertained from
   /// SIL and the AST.
diff --git a/include/swift/SILOptimizer/Utils/SILInliner.h b/include/swift/SILOptimizer/Utils/SILInliner.h
index 928072dd6e788..b5ccdd156a96f 100644
--- a/include/swift/SILOptimizer/Utils/SILInliner.h
+++ b/include/swift/SILOptimizer/Utils/SILInliner.h
@@ -41,7 +41,7 @@ InlineCost instructionInlineCost(SILInstruction &I);
 
 class SILInliner {
 public:
-  enum class InlineKind { MandatoryInline, PerformanceInline };
+  enum class InlineKind { MandatoryInline, PerformanceInline, InlineAlwaysInline };
 
   using DeletionFuncTy = std::function<void(SILInstruction *)>;
 
diff --git a/include/swift/SILOptimizer/Utils/SILIsolationInfo.h b/include/swift/SILOptimizer/Utils/SILIsolationInfo.h
index 114759dcc7b17..54f2916695a6a 100644
--- a/include/swift/SILOptimizer/Utils/SILIsolationInfo.h
+++ b/include/swift/SILOptimizer/Utils/SILIsolationInfo.h
@@ -71,7 +71,14 @@ class ActorInstance {
   ActorInstance() : ActorInstance(SILValue(), Kind::Value) {}
 
   static ActorInstance getForValue(SILValue value) {
+    if (!value)
+      return ActorInstance();
     value = lookThroughInsts(value);
+    if (!value->getType()
+             .getASTType()
+             ->lookThroughAllOptionalTypes()
+             ->isAnyActorType())
+      return ActorInstance();
     return ActorInstance(value, Kind::Value);
   }
 
@@ -96,7 +103,7 @@ class ActorInstance {
     return value.getPointer();
   }
 
-  SILValue maybeGetValue() const {
+  LLVM_ATTRIBUTE_USED SILValue maybeGetValue() const {
     if (getKind() != Kind::Value)
       return SILValue();
     return getValue();
@@ -132,6 +139,10 @@ class ActorInstance {
   bool operator!=(const ActorInstance &other) const {
     return !(*this == other);
   }
+
+  void print(llvm::raw_ostream &os) const;
+
+  SWIFT_DEBUG_DUMP { print(llvm::dbgs()); }
 };
 
 /// The isolation info inferred for a specific SILValue. Use
@@ -174,8 +185,12 @@ class SILIsolationInfo {
     /// parameter and should be allowed to merge into a self parameter.
     UnappliedIsolatedAnyParameter = 0x2,
 
+    /// If set, this was a TaskIsolated value from a nonisolated(nonsending)
+    /// parameter.
+    NonisolatedNonsendingTaskIsolated = 0x4,
+
     /// The maximum number of bits used by a Flag.
-    MaxNumBits = 2,
+    MaxNumBits = 3,
   };
 
   using Options = OptionSet<Flag>;
@@ -193,13 +208,19 @@ class SILIsolationInfo {
   /// derived isolatedValue from.
   ActorInstance actorInstance;
 
+  /// When the isolation is introduced due to a (potentially) isolated
+  /// conformance, the protocol whose conformance might be isolated.
+  ProtocolDecl *isolatedConformance = nullptr;
+
   unsigned kind : 8;
   unsigned options : 8;
 
   SILIsolationInfo(SILValue isolatedValue, SILValue actorInstance,
-                   ActorIsolation actorIsolation, Options options = Options())
+                   ActorIsolation actorIsolation, Options options = Options(),
+                   ProtocolDecl *isolatedConformance = nullptr)
       : actorIsolation(actorIsolation), isolatedValue(isolatedValue),
-        actorInstance(ActorInstance::getForValue(actorInstance)), kind(Actor),
+        actorInstance(ActorInstance::getForValue(actorInstance)),
+        isolatedConformance(isolatedConformance), kind(Actor),
         options(options.toRaw()) {
     assert((!actorInstance ||
             (actorIsolation.getKind() == ActorIsolation::ActorInstance &&
@@ -208,23 +229,39 @@ class SILIsolationInfo {
                  ->lookThroughAllOptionalTypes()
                  ->getAnyActor())) &&
            "actorInstance must be an actor if it is non-empty");
+    assert((getKind() != Disconnected || isolatedConformance == nullptr) &&
+        "isolated conformance cannot be introduced with disconnected region");
   }
 
   SILIsolationInfo(SILValue isolatedValue, ActorInstance actorInstance,
-                   ActorIsolation actorIsolation, Options options = Options())
+                   ActorIsolation actorIsolation, Options options = Options(),
+                   ProtocolDecl *isolatedConformance = nullptr)
       : actorIsolation(actorIsolation), isolatedValue(isolatedValue),
-        actorInstance(actorInstance), kind(Actor), options(options.toRaw()) {
+        actorInstance(actorInstance), isolatedConformance(isolatedConformance),
+        kind(Actor), options(options.toRaw())
+  {
     assert(actorInstance);
     assert(actorIsolation.getKind() == ActorIsolation::ActorInstance);
   }
 
-  SILIsolationInfo(Kind kind, SILValue isolatedValue)
-      : actorIsolation(), isolatedValue(isolatedValue), kind(kind), options(0) {
+  SILIsolationInfo(Kind kind, SILValue isolatedValue,
+                   ProtocolDecl *isolatedConformance = nullptr)
+      : actorIsolation(), isolatedValue(isolatedValue),
+        isolatedConformance(isolatedConformance), kind(kind), options(0) {
   }
 
   SILIsolationInfo(Kind kind, Options options = Options())
       : actorIsolation(), kind(kind), options(options.toRaw()) {}
 
+  /// Infer isolation region from the set of protocol conformances.
+  static SILIsolationInfo getFromConformances(
+      SILValue value, ArrayRef<ProtocolConformanceRef> conformances);
+
+  /// Determine the isolation of conformances that could be introduced by a
+  /// cast from sourceType to destType.
+  static SILIsolationInfo getForCastConformances(
+      SILValue value, CanType sourceType, CanType destType);
+
 public:
   SILIsolationInfo() : actorIsolation(), kind(Kind::Unknown), options(0) {}
 
@@ -246,6 +283,12 @@ class SILIsolationInfo {
     return getOptions().contains(Flag::UnsafeNonIsolated);
   }
 
+  // Retrieve the protocol to which there is (or could be) an isolated
+  // conformance.
+  ProtocolDecl *getIsolatedConformance() const {
+    return isolatedConformance;
+  }
+
   SILIsolationInfo withUnsafeNonIsolated(bool newValue = true) const {
     assert(*this && "Cannot be unknown");
     auto self = *this;
@@ -258,6 +301,45 @@ class SILIsolationInfo {
     return self;
   }
 
+  bool isNonisolatedNonsendingTaskIsolated() const {
+    return getOptions().contains(Flag::NonisolatedNonsendingTaskIsolated);
+  }
+
+  SILIsolationInfo
+  withNonisolatedNonsendingTaskIsolated(bool newValue = true) const {
+    assert(*this && "Cannot be unknown");
+    assert(isTaskIsolated() && "Can only be task isolated");
+    auto self = *this;
+    if (newValue) {
+      self.options =
+          (self.getOptions() | Flag::NonisolatedNonsendingTaskIsolated).toRaw();
+    } else {
+      self.options = self.getOptions().toRaw() &
+                     ~Options(Flag::NonisolatedNonsendingTaskIsolated).toRaw();
+    }
+    return self;
+  }
+
+  /// Produce a new isolation info value that merges in the given isolated
+  /// conformance value.
+  ///
+  /// If both isolation infos have an isolation conformance, pick one
+  /// arbitrarily. Otherwise, the result has no isolated conformance.
+  SILIsolationInfo
+  withMergedIsolatedConformance(ProtocolDecl *newIsolatedConformance) const {
+    SILIsolationInfo result(*this);
+    if (!isolatedConformance || !newIsolatedConformance) {
+      result.isolatedConformance = nullptr;
+      return result;
+    }
+
+    result.isolatedConformance =
+      ProtocolDecl::compare(isolatedConformance, newIsolatedConformance) <= 0
+        ? isolatedConformance
+        : newIsolatedConformance;
+    return result;
+  }
+
   /// Returns true if this actor isolation is derived from an unapplied
   /// isolation parameter. When merging, we allow for this to be merged with a
   /// more specific isolation kind.
@@ -278,16 +360,16 @@ class SILIsolationInfo {
     return self;
   }
 
-  void print(llvm::raw_ostream &os) const;
+  void print(SILFunction *fn, llvm::raw_ostream &os) const;
 
   /// Print a textual representation of the text info that is meant to be
   /// included in other logging output for types that compose with
   /// SILIsolationInfo. As a result, we only print state that can fit on
   /// one line.
-  void printForOneLineLogging(llvm::raw_ostream &os) const;
+  void printForOneLineLogging(SILFunction *fn, llvm::raw_ostream &os) const;
 
-  SWIFT_DEBUG_DUMP {
-    print(llvm::dbgs());
+  SWIFT_DEBUG_DUMPER(dump(SILFunction *fn)) {
+    print(fn, llvm::dbgs());
     llvm::dbgs() << '\n';
   }
 
@@ -296,12 +378,20 @@ class SILIsolationInfo {
   ///
   /// We do this programatically since task-isolated code needs a very different
   /// form of diagnostic than other cases.
-  void printForCodeDiagnostic(llvm::raw_ostream &os) const;
+  void printForCodeDiagnostic(SILFunction *fn, llvm::raw_ostream &os) const;
+
+  /// Overload of printForCodeDiagnostics that returns an interned StringRef
+  /// owned by the AST.
+  StringRef printForCodeDiagnostic(SILFunction *fn) const;
 
-  void printForDiagnostics(llvm::raw_ostream &os) const;
+  void printForDiagnostics(SILFunction *fn, llvm::raw_ostream &os) const;
 
-  SWIFT_DEBUG_DUMPER(dumpForDiagnostics()) {
-    printForDiagnostics(llvm::dbgs());
+  /// Overload of printForDiagnostics that returns an interned StringRef owned
+  /// by the AST.
+  StringRef printForDiagnostics(SILFunction *fn) const;
+
+  SWIFT_DEBUG_DUMPER(dumpForDiagnostics(SILFunction *fn)) {
+    printForDiagnostics(fn, llvm::dbgs());
     llvm::dbgs() << '\n';
   }
 
@@ -372,6 +462,21 @@ class SILIsolationInfo {
             ActorIsolation::forActorInstanceSelf(typeDecl)};
   }
 
+  static SILIsolationInfo
+  getActorInstanceIsolated(SILValue isolatedValue,
+                           const SILFunctionArgument *actorInstance) {
+    assert(actorInstance);
+    auto *varDecl =
+        llvm::dyn_cast_if_present<VarDecl>(actorInstance->getDecl());
+    if (!varDecl)
+      return {};
+    return {isolatedValue, actorInstance,
+            actorInstance->isSelf()
+                ? ActorIsolation::forActorInstanceSelf(varDecl)
+                : ActorIsolation::forActorInstanceParameter(
+                      varDecl, actorInstance->getIndex())};
+  }
+
   static SILIsolationInfo getActorInstanceIsolated(SILValue isolatedValue,
                                                    ActorInstance actorInstance,
                                                    NominalTypeDecl *typeDecl) {
@@ -401,10 +506,13 @@ class SILIsolationInfo {
             Flag::UnappliedIsolatedAnyParameter};
   }
 
-  static SILIsolationInfo getGlobalActorIsolated(SILValue value,
-                                                 Type globalActorType) {
+  static SILIsolationInfo getGlobalActorIsolated(
+      SILValue value,
+      Type globalActorType,
+      ProtocolDecl *isolatedConformance = nullptr) {
     return {value, SILValue() /*no actor instance*/,
-            ActorIsolation::forGlobalActor(globalActorType)};
+            ActorIsolation::forGlobalActor(globalActorType),
+            Options(), isolatedConformance};
   }
 
   static SILIsolationInfo getGlobalActorIsolated(SILValue value,
@@ -416,8 +524,9 @@ class SILIsolationInfo {
                                                     isolation.getGlobalActor());
   }
 
-  static SILIsolationInfo getTaskIsolated(SILValue value) {
-    return {Kind::Task, value};
+  static SILIsolationInfo getTaskIsolated(
+      SILValue value, ProtocolDecl *isolatedConformance = nullptr) {
+    return {Kind::Task, value, isolatedConformance};
   }
 
   /// Attempt to infer the isolation region info for \p inst.
@@ -434,6 +543,14 @@ class SILIsolationInfo {
     return {};
   }
 
+  /// Infer isolation of conformances for the given instruction.
+  static SILIsolationInfo getConformanceIsolation(SILInstruction *inst);
+
+  /// Return SILIsolationInfo based off of the attached ActorIsolation of \p
+  /// fn. If \p fn does not have an actor isolation set, returns an invalid
+  /// SILIsolationInfo.
+  static SILIsolationInfo getFunctionIsolation(SILFunction *fn);
+
   /// A helper that is used to ensure that we treat certain builtin values as
   /// non-Sendable that the AST level otherwise thinks are non-Sendable.
   ///
@@ -442,17 +559,25 @@ class SILIsolationInfo {
   /// TODO: Fix the type checker.
   static bool isNonSendableType(SILType type, SILFunction *fn);
 
+  static bool isSendableType(SILType type, SILFunction *fn) {
+    return !isNonSendableType(type, fn);
+  }
+
   static bool isNonSendableType(SILValue value) {
     return isNonSendableType(value->getType(), value->getFunction());
   }
 
+  static bool isSendableType(SILValue value) {
+    return !isNonSendableType(value);
+  }
+
   bool hasSameIsolation(ActorIsolation actorIsolation) const;
 
   /// Returns true if \p this and \p other have the same isolation. It allows
   /// for the isolated values if any to not match.
   ///
   /// This is useful if one has two non-Sendable values projected from the same
-  /// actor or global actor isolated value. E.x.: two different ref_element_addr
+  /// actor or global-actor-isolated value. E.x.: two different ref_element_addr
   /// from the same actor.
   bool hasSameIsolation(const SILIsolationInfo &other) const;
 
@@ -460,6 +585,19 @@ class SILIsolationInfo {
   /// that the isolation and the isolated value match.
   bool isEqual(const SILIsolationInfo &other) const;
 
+  /// A helper function that prints ActorIsolation like we normally do except
+  /// that it prints nonisolated(nonsending) as nonisolated. This is needed in
+  /// certain cases when talking about use-after-free uses in send non sendable.
+  static void printActorIsolationForDiagnostics(
+      SILFunction *fn, ActorIsolation iso, llvm::raw_ostream &os,
+      StringRef openingQuotationMark = "'", bool asNoun = false);
+
+  /// Overload for printActorIsolationForDiagnostics that produces a StringRef.
+  static StringRef
+  printActorIsolationForDiagnostics(SILFunction *fn, ActorIsolation iso,
+                                    StringRef openingQuotationMark = "'",
+                                    bool asNoun = false);
+
   void Profile(llvm::FoldingSetNodeID &id) const;
 
 private:
@@ -523,43 +661,33 @@ class SILDynamicMergedIsolationInfo {
         SILIsolationInfo::getDisconnected(isUnsafeNonIsolated));
   }
 
-  SWIFT_DEBUG_DUMP { innerInfo.dump(); }
+  SWIFT_DEBUG_DUMPER(dump(SILFunction *fn)) { innerInfo.dump(fn); }
 
-  void printForDiagnostics(llvm::raw_ostream &os) const {
-    innerInfo.printForDiagnostics(os);
+  void printForDiagnostics(SILFunction *fn, llvm::raw_ostream &os) const {
+    innerInfo.printForDiagnostics(fn, os);
   }
 
-  SWIFT_DEBUG_DUMPER(dumpForDiagnostics()) {
-    innerInfo.dumpForDiagnostics();
+  StringRef printForDiagnostics(SILFunction *fn) const {
+    return innerInfo.printForDiagnostics(fn);
   }
 
-  void printForCodeDiagnostic(llvm::raw_ostream &os) const {
-    innerInfo.printForCodeDiagnostic(os);
+  SWIFT_DEBUG_DUMPER(dumpForDiagnostics(SILFunction *fn)) {
+    innerInfo.dumpForDiagnostics(fn);
   }
 
-  void printForOneLineLogging(llvm::raw_ostream &os) const {
-    innerInfo.printForOneLineLogging(os);
+  void printForCodeDiagnostic(SILFunction *fn, llvm::raw_ostream &os) const {
+    innerInfo.printForCodeDiagnostic(fn, os);
   }
-};
 
-} // namespace swift
-
-namespace llvm {
-
-inline llvm::raw_ostream &
-operator<<(llvm::raw_ostream &os,
-           const swift::SILIsolationInfo &isolationInfo) {
-  isolationInfo.printForOneLineLogging(os);
-  return os;
-}
+  StringRef printForCodeDiagnostic(SILFunction *fn) const {
+    return innerInfo.printForCodeDiagnostic(fn);
+  }
 
-inline llvm::raw_ostream &
-operator<<(llvm::raw_ostream &os,
-           const swift::SILDynamicMergedIsolationInfo &isolationInfo) {
-  isolationInfo.printForOneLineLogging(os);
-  return os;
-}
+  void printForOneLineLogging(SILFunction *fn, llvm::raw_ostream &os) const {
+    innerInfo.printForOneLineLogging(fn, os);
+  }
+};
 
-} // namespace llvm
+} // namespace swift
 
 #endif
diff --git a/include/swift/SILOptimizer/Utils/SpecializationMangler.h b/include/swift/SILOptimizer/Utils/SpecializationMangler.h
index 058c912e5a261..0ceaf6517d7f7 100644
--- a/include/swift/SILOptimizer/Utils/SpecializationMangler.h
+++ b/include/swift/SILOptimizer/Utils/SpecializationMangler.h
@@ -68,6 +68,7 @@ class FunctionSignatureSpecializationMangler : public SpecializationMangler {
     BoxToValue = 3,
     BoxToStack = 4,
     InOutToOut = 5,
+    ClosurePropPreviousArg = 6, // the same closure as a previous `ClosureProp` argument
 
     First_Option = 0,
     Last_Option = 31,
@@ -82,8 +83,20 @@ class FunctionSignatureSpecializationMangler : public SpecializationMangler {
     LastOptionSetEntry = 32768,
   };
 
-  using ArgInfo = std::pair<ArgumentModifierIntBase,
-                            NullablePtr<SILInstruction>>;
+  struct ArgInfo {
+    ArgumentModifier kind;
+    union {
+      SILInstruction *inst;
+      unsigned otherArgIdx; // only for `ClosurePropPreviousArg`
+    };
+
+    ArgInfo(ArgumentModifier kind) : kind(kind), inst(nullptr) {}
+
+    void append(ArgumentModifier modifier) {
+      kind = ArgumentModifier(ArgumentModifierIntBase(kind) | ArgumentModifierIntBase(modifier));
+    }
+  };
+
   // Information for each SIL argument in the original function before
   // specialization. This includes SIL indirect result argument required for
   // the original function type at the current stage of compilation.
@@ -99,9 +112,8 @@ class FunctionSignatureSpecializationMangler : public SpecializationMangler {
   void setArgumentConstantProp(unsigned OrigArgIdx, SILInstruction *constInst);
   void appendStringAsIdentifier(StringRef str);
 
-  void setArgumentClosureProp(unsigned OrigArgIdx, PartialApplyInst *PAI);
-  void setArgumentClosureProp(unsigned OrigArgIdx,
-                              ThinToThickFunctionInst *TTTFI);
+  void setArgumentClosureProp(unsigned OrigArgIdx, SILInstruction *closure);
+  void setArgumentClosurePropPreviousArg(unsigned OrigArgIdx, unsigned otherArgIdx);
   void setArgumentDead(unsigned OrigArgIdx);
   void setArgumentOwnedToGuaranteed(unsigned OrigArgIdx);
   void setArgumentGuaranteedToOwned(unsigned OrigArgIdx);
@@ -120,8 +132,7 @@ class FunctionSignatureSpecializationMangler : public SpecializationMangler {
 private:
   void mangleConstantProp(SILInstruction *constInst);
   void mangleClosureProp(SILInstruction *Inst);
-  void mangleArgument(ArgumentModifierIntBase ArgMod,
-                      NullablePtr<SILInstruction> Inst);
+  void mangleArgument(ArgInfo argInfo);
   void mangleReturnValue(ReturnValueModifierIntBase RetMod);
 };
 
diff --git a/include/swift/SILOptimizer/Utils/ValueLifetime.h b/include/swift/SILOptimizer/Utils/ValueLifetime.h
index 231bcb75328f0..8bde0cbd7759c 100644
--- a/include/swift/SILOptimizer/Utils/ValueLifetime.h
+++ b/include/swift/SILOptimizer/Utils/ValueLifetime.h
@@ -223,14 +223,14 @@ class ValueLifetimeAnalysis {
     if (auto *inst = defValue.dyn_cast<SILInstruction *>()) {
       return inst->getFunction();
     }
-    return defValue.get<SILArgument *>()->getFunction();
+    return cast<SILArgument *>(defValue)->getFunction();
   }
 
   SILBasicBlock *getDefValueParentBlock() const {
     if (auto *inst = defValue.dyn_cast<SILInstruction *>()) {
       return inst->getParent();
     }
-    return defValue.get<SILArgument *>()->getParent();
+    return cast<SILArgument *>(defValue)->getParent();
   }
 
   /// Propagates the liveness information up the control flow graph.
diff --git a/include/swift/Sema/CSBindings.h b/include/swift/Sema/CSBindings.h
index e67ad8602ee8b..3e17979652d90 100644
--- a/include/swift/Sema/CSBindings.h
+++ b/include/swift/Sema/CSBindings.h
@@ -118,10 +118,10 @@ struct PotentialBinding {
   ConstraintLocator *getLocator() const {
     if (auto *constraint = BindingSource.dyn_cast<Constraint *>())
       return constraint->getLocator();
-    return BindingSource.get<ConstraintLocator *>();
+    return cast<ConstraintLocator *>(BindingSource);
   }
 
-  Constraint *getSource() const { return BindingSource.get<Constraint *>(); }
+  Constraint *getSource() const { return cast<Constraint *>(BindingSource); }
 
   PotentialBinding withType(Type type) const {
     return {type, Kind, BindingSource};
@@ -527,6 +527,12 @@ class BindingSet {
   void forEachLiteralRequirement(
       llvm::function_ref<void(KnownProtocolKind)> callback) const;
 
+  void forEachAdjacentVariable(
+      llvm::function_ref<void(TypeVariableType *)> callback) const {
+    for (auto *typeVar : AdjacentVars)
+      callback(typeVar);
+  }
+
   /// Return a literal requirement that has the most impact on the binding
   /// score.
   LiteralBindingKind getLiteralForScore() const;
diff --git a/include/swift/Sema/CSFix.h b/include/swift/Sema/CSFix.h
index 159e5a86a2fba..b7ee59d1ea460 100644
--- a/include/swift/Sema/CSFix.h
+++ b/include/swift/Sema/CSFix.h
@@ -394,6 +394,9 @@ enum class FixKind : uint8_t {
   /// Ignore a type imposed by an assignment destination e.g. `let x: Int = ...`
   IgnoreAssignmentDestinationType,
 
+  /// Ignore a non-metatype contextual type for a `type(of:)` expression.
+  IgnoreNonMetatypeDynamicType,
+
   /// Allow argument-to-parameter subtyping even when parameter type
   /// is marked as `inout`.
   AllowConversionThroughInOut,
@@ -488,6 +491,9 @@ enum class FixKind : uint8_t {
   /// the type it's attempting to bind to.
   AllowInlineArrayLiteralCountMismatch,
 
+  /// Reached the limit of @dynamicMemberLookup depth.
+  TooManyDynamicMemberLookups,
+
   /// Ignore that a conformance is isolated but is not allowed to be.
   IgnoreIsolatedConformance,
 };
@@ -560,6 +566,11 @@ class ConstraintFix {
     return false;
   }
 
+  template <typename E>
+  bool directlyAt() const {
+    return getLocator()->directlyAt<E>();
+  }
+
   void print(llvm::raw_ostream &Out) const;
 
   SWIFT_DEBUG_DUMP;
@@ -655,7 +666,7 @@ class RelabelArguments final
   std::string getName() const override { return "re-label argument(s)"; }
 
   ArrayRef<Identifier> getLabels() const {
-    return {getTrailingObjects<Identifier>(), NumLabels};
+    return getTrailingObjects(NumLabels);
   }
 
   bool diagnose(const Solution &solution, bool asNote = false) const override;
@@ -672,7 +683,7 @@ class RelabelArguments final
 
 private:
   MutableArrayRef<Identifier> getLabelsBuffer() {
-    return {getTrailingObjects<Identifier>(), NumLabels};
+    return getTrailingObjects(NumLabels);
   }
 };
 
@@ -848,12 +859,12 @@ class ContextualMismatch : public ConstraintFix {
     // produce another diagnostic for the contextual mismatch complaining that
     // a type is not convertible to a placeholder type.
     if (auto fromPlaceholder = getFromType()->getAs<PlaceholderType>()) {
-      if (fromPlaceholder->getOriginator().is<ErrorExpr *>()) {
+      if (isa<ErrorExpr *>(fromPlaceholder->getOriginator())) {
         return true;
       }
     }
     if (auto toPlaceholder = getToType()->getAs<PlaceholderType>()) {
-      if (toPlaceholder->getOriginator().is<ErrorExpr *>()) {
+      if (isa<ErrorExpr *>(toPlaceholder->getOriginator())) {
         return true;
       }
     }
@@ -1193,7 +1204,7 @@ class GenericArgumentsMismatch final
   }
 
   ArrayRef<unsigned> getMismatches() const {
-    return {getTrailingObjects<unsigned>(), NumMismatches};
+    return getTrailingObjects(NumMismatches);
   }
 
   bool coalesceAndDiagnose(const Solution &solution,
@@ -1216,7 +1227,7 @@ class GenericArgumentsMismatch final
                 bool asNote = false) const;
 
   MutableArrayRef<unsigned> getMismatchesBuf() {
-    return {getTrailingObjects<unsigned>(), NumMismatches};
+    return getTrailingObjects(NumMismatches);
   }
 };
 
@@ -1786,7 +1797,7 @@ class AddMissingArguments final
   std::string getName() const override { return "synthesize missing argument(s)"; }
 
   ArrayRef<SynthesizedArg> getSynthesizedArguments() const {
-    return {getTrailingObjects<SynthesizedArg>(), NumSynthesized};
+    return getTrailingObjects(NumSynthesized);
   }
 
   bool diagnose(const Solution &solution, bool asNote = false) const override;
@@ -1805,7 +1816,7 @@ class AddMissingArguments final
 
 private:
   MutableArrayRef<SynthesizedArg> getSynthesizedArgumentsBuf() {
-    return {getTrailingObjects<SynthesizedArg>(), NumSynthesized};
+    return getTrailingObjects(NumSynthesized);
   }
 };
 
@@ -1834,7 +1845,7 @@ class RemoveExtraneousArguments final
   std::string getName() const override { return "remove extraneous argument(s)"; }
 
   ArrayRef<IndexedParam> getExtraArguments() const {
-    return {getTrailingObjects<IndexedParam>(), NumExtraneous};
+    return getTrailingObjects(NumExtraneous);
   }
 
   bool diagnose(const Solution &solution, bool asNote = false) const override;
@@ -1862,7 +1873,7 @@ class RemoveExtraneousArguments final
 
 private:
   MutableArrayRef<IndexedParam> getExtraArgumentsBuf() {
-    return {getTrailingObjects<IndexedParam>(), NumExtraneous};
+    return getTrailingObjects(NumExtraneous);
   }
 };
 
@@ -2019,6 +2030,8 @@ class AllowInvalidRefInKeyPath final : public ConstraintFix {
     AsyncOrThrowsMethod,
     // Allow a reference to an enum case as a key path component.
     EnumCase,
+    // Allow a reference to a type as a key path component.
+    TypeReference,
   } Kind;
 
   ValueDecl *Member;
@@ -2051,6 +2064,8 @@ class AllowInvalidRefInKeyPath final : public ConstraintFix {
     case RefKind::AsyncOrThrowsMethod:
       return "allow reference to async or throwing method as a key path "
              "component";
+    case RefKind::TypeReference:
+      return "allow reference to a type as a key path component";
     }
     llvm_unreachable("covered switch");
   }
@@ -2262,7 +2277,7 @@ class CollectionElementContextualMismatch final
   }
 
   ArrayRef<Expr *> getElements() const {
-    return {getTrailingObjects<Expr *>(), NumElements};
+    return getTrailingObjects(NumElements);
   }
 
   bool diagnose(const Solution &solution, bool asNote = false) const override;
@@ -2277,7 +2292,7 @@ class CollectionElementContextualMismatch final
 
 private:
   MutableArrayRef<Expr *> getElementBuffer() {
-    return {getTrailingObjects<Expr *>(), NumElements};
+    return getTrailingObjects(NumElements);
   }
 };
 
@@ -2422,6 +2437,30 @@ class IgnoreAssignmentDestinationType final : public ContextualMismatch {
   }
 };
 
+/// Ignore a non-metatype contextual type for a `type(of:)` expression, for
+/// example `let x: Int = type(of: foo)`.
+class IgnoreNonMetatypeDynamicType final : public ContextualMismatch {
+  IgnoreNonMetatypeDynamicType(ConstraintSystem &cs, Type instanceTy,
+                               Type metatypeTy, ConstraintLocator *locator)
+      : ContextualMismatch(cs, FixKind::IgnoreNonMetatypeDynamicType,
+                           instanceTy, metatypeTy, locator) {}
+
+public:
+  std::string getName() const override {
+    return "ignore non-metatype result for 'type(of:)'";
+  }
+
+  bool diagnose(const Solution &solution, bool asNote = false) const override;
+
+  static IgnoreNonMetatypeDynamicType *create(ConstraintSystem &cs,
+                                              Type instanceTy, Type metatypeTy,
+                                              ConstraintLocator *locator);
+
+  static bool classof(const ConstraintFix *fix) {
+    return fix->getKind() == FixKind::IgnoreNonMetatypeDynamicType;
+  }
+};
+
 /// If this is an argument-to-parameter conversion which is associated with
 /// `inout` parameter, subtyping is not permitted, types have to
 /// be identical.
@@ -3516,14 +3555,14 @@ class RenameConflictingPatternVariables final
   }
 
   MutableArrayRef<VarDecl *> getConflictingBuffer() {
-    return {getTrailingObjects<VarDecl *>(), NumConflicts};
+    return getTrailingObjects(NumConflicts);
   }
 
 public:
   std::string getName() const override { return "rename pattern variables"; }
 
   ArrayRef<VarDecl *> getConflictingVars() const {
-    return {getTrailingObjects<VarDecl *>(), NumConflicts};
+    return getTrailingObjects(NumConflicts);
   }
 
   bool diagnose(const Solution &solution, bool asNote = false) const override;
@@ -3876,6 +3915,33 @@ class AllowInlineArrayLiteralCountMismatch final : public ConstraintFix {
   }
 };
 
+class TooManyDynamicMemberLookups : public ConstraintFix {
+  DeclNameRef Name;
+
+  TooManyDynamicMemberLookups(ConstraintSystem &cs, DeclNameRef name,
+                              ConstraintLocator *locator)
+      : ConstraintFix(cs, FixKind::TooManyDynamicMemberLookups, locator),
+        Name(name) {}
+
+public:
+  std::string getName() const override {
+    return "too many dynamic member lookups";
+  }
+
+  bool diagnose(const Solution &solution, bool asNote = false) const override;
+
+  bool diagnoseForAmbiguity(CommonFixesArray commonFixes) const override {
+    return diagnose(*commonFixes.front().first);
+  }
+
+  static TooManyDynamicMemberLookups *
+  create(ConstraintSystem &cs, DeclNameRef name, ConstraintLocator *locator);
+
+  static bool classof(const ConstraintFix *fix) {
+    return fix->getKind() == FixKind::TooManyDynamicMemberLookups;
+  }
+};
+
 class IgnoreIsolatedConformance : public ConstraintFix {
   ProtocolConformance *conformance;
 
diff --git a/include/swift/Sema/CompletionContextFinder.h b/include/swift/Sema/CompletionContextFinder.h
index 6d271021194ba..89c9fb9da2045 100644
--- a/include/swift/Sema/CompletionContextFinder.h
+++ b/include/swift/Sema/CompletionContextFinder.h
@@ -25,22 +25,6 @@ class SyntacticElementTarget;
 }
 
 class CompletionContextFinder : public ASTWalker {
-  enum class ContextKind {
-    FallbackExpression,
-    StringInterpolation,
-    SingleStmtClosure,
-    MultiStmtClosure,
-    ErrorExpression
-  };
-
-  struct Context {
-    ContextKind Kind;
-    Expr *E;
-  };
-
-  /// Stack of all "interesting" contexts up to code completion expression.
-  llvm::SmallVector<Context, 4> Contexts;
-
   /// If we are completing inside an expression, the \c CodeCompletionExpr that
   /// represents the code completion token.
 
@@ -49,51 +33,25 @@ class CompletionContextFinder : public ASTWalker {
   /// component.
   llvm::PointerUnion<CodeCompletionExpr *, const KeyPathExpr *> CompletionNode;
 
-  Expr *InitialExpr = nullptr;
-  DeclContext *InitialDC;
-
-  /// Whether we're looking for any viable fallback expression.
-  bool ForFallback = false;
-
-  /// Finder for fallback completion contexts within the outermost non-closure
-  /// context of the code completion expression's direct context.
-  CompletionContextFinder(DeclContext *completionDC)
-    : InitialDC(completionDC), ForFallback(true) {
-    while (auto *ACE = dyn_cast<AbstractClosureExpr>(InitialDC))
-      InitialDC = ACE->getParent();
-    InitialDC->walkContext(*this);
-  }
-
 public:
   MacroWalking getMacroWalkingBehavior() const override {
     return MacroWalking::Arguments;
   }
 
   /// Finder for completion contexts within the provided SyntacticElementTarget.
-  CompletionContextFinder(constraints::SyntacticElementTarget target,
-                          DeclContext *DC);
-
-  static CompletionContextFinder forFallback(DeclContext *DC) {
-    return CompletionContextFinder(DC);
-  }
+  CompletionContextFinder(constraints::SyntacticElementTarget target);
 
   PreWalkResult<Expr *> walkToExprPre(Expr *E) override;
 
-  PostWalkResult<Expr *> walkToExprPost(Expr *E) override;
-
   PreWalkAction walkToDeclPre(Decl *D) override;
 
-  bool locatedInStringInterpolation() const {
-    return hasContext(ContextKind::StringInterpolation);
-  }
-
   bool hasCompletionExpr() const {
     return CompletionNode.dyn_cast<CodeCompletionExpr *>() != nullptr;
   }
 
   CodeCompletionExpr *getCompletionExpr() const {
     assert(hasCompletionExpr());
-    return CompletionNode.get<CodeCompletionExpr *>();
+    return cast<CodeCompletionExpr *>(CompletionNode);
   }
 
   bool hasCompletionKeyPathComponent() const {
@@ -108,34 +66,14 @@ class CompletionContextFinder : public ASTWalker {
   /// the code completion component.
   const KeyPathExpr *getKeyPathContainingCompletionComponent() const {
     assert(hasCompletionKeyPathComponent());
-    return CompletionNode.get<const KeyPathExpr *>();
+    return cast<const KeyPathExpr *>(CompletionNode);
   }
 
   /// If we are completing in a key path, returns the index at which the key
   /// path has the code completion component.
   size_t getKeyPathCompletionComponentIndex() const;
-
-  struct Fallback {
-    Expr *E;               ///< The fallback expression.
-    DeclContext *DC;       ///< The fallback expression's decl context.
-    bool SeparatePrecheck; ///< True if the fallback may require prechecking.
-  };
-
-  /// As a fallback sometimes its useful to not only type-check
-  /// code completion expression directly but instead add some
-  /// of the enclosing context e.g. when completion is an argument
-  /// to a call.
-  std::optional<Fallback> getFallbackCompletionExpr() const;
-
-private:
-  bool hasContext(ContextKind kind) const {
-    return llvm::find_if(Contexts, [&kind](const Context &currContext) {
-             return currContext.Kind == kind;
-           }) != Contexts.end();
-  }
 };
 
-
 /// Returns \c true if \p range is valid and contains the IDE inspection
 /// target. This performs the underlying check based on \c CharSourceRange
 /// to make sure we correctly return \c true if the ide inspection target
diff --git a/include/swift/Sema/Concurrency.h b/include/swift/Sema/Concurrency.h
index 1f919941ec648..f82f9500616ee 100644
--- a/include/swift/Sema/Concurrency.h
+++ b/include/swift/Sema/Concurrency.h
@@ -36,7 +36,7 @@ struct DiagnosticBehavior;
 /// that the attribute be removed.
 void diagnoseUnnecessaryPreconcurrencyImports(SourceFile &sf);
 
-/// Diagnose the use of an instance property of non-sendable type from an
+/// Diagnose the use of an instance property of non-Sendable type from an
 /// nonisolated deinitializer within an actor-isolated type.
 ///
 /// \returns true iff a diagnostic was emitted for this reference.
diff --git a/include/swift/Sema/Constraint.h b/include/swift/Sema/Constraint.h
index 72db2f161ba39..97f2953a72863 100644
--- a/include/swift/Sema/Constraint.h
+++ b/include/swift/Sema/Constraint.h
@@ -49,6 +49,7 @@ namespace constraints {
 class ConstraintFix;
 class ConstraintLocator;
 class ConstraintSystem;
+class PreparedOverload;
 enum class TrailingClosureMatching;
 
 /// Describes the kind of constraint placed on one or more types.
@@ -437,6 +438,9 @@ class Constraint final : public llvm::ilist_node<Constraint>,
     struct {
       /// The first type.
       Type First;
+
+      /// The prepared overload, if any.
+      PreparedOverload *Prepared;
     } Overload;
 
     struct {
@@ -490,7 +494,8 @@ class Constraint final : public llvm::ilist_node<Constraint>,
              SmallPtrSetImpl<TypeVariableType *> &typeVars);
 
   /// Construct a new overload-binding constraint, which might have a fix.
-  Constraint(Type type, OverloadChoice choice, DeclContext *useDC,
+  Constraint(Type type, OverloadChoice choice,
+             DeclContext *useDC,
              ConstraintFix *fix, ConstraintLocator *locator,
              SmallPtrSetImpl<TypeVariableType *> &typeVars);
 
@@ -871,6 +876,19 @@ class Constraint final : public llvm::ilist_node<Constraint>,
     return *getTrailingObjects<OverloadChoice>();
   }
 
+  /// Retrieve the prepared overload choice for an overload-binding
+  /// constraint.
+  PreparedOverload *getPreparedOverload() const {
+    ASSERT(Kind == ConstraintKind::BindOverload);
+    return Overload.Prepared;
+  }
+
+  void setPreparedOverload(PreparedOverload *preparedOverload) {
+    ASSERT(Kind == ConstraintKind::BindOverload);
+    ASSERT(!Overload.Prepared);
+    Overload.Prepared = preparedOverload;
+  }
+
   FunctionType *getAppliedFunctionType() const {
     assert(Kind == ConstraintKind::ApplicableFunction);
     return Apply.AppliedFn;
diff --git a/include/swift/Sema/ConstraintGraph.h b/include/swift/Sema/ConstraintGraph.h
index d4f0b1ef6e4cc..52a723d0ca840 100644
--- a/include/swift/Sema/ConstraintGraph.h
+++ b/include/swift/Sema/ConstraintGraph.h
@@ -216,7 +216,7 @@ class ConstraintGraphNode {
 
   /// Print this graph node.
   void print(llvm::raw_ostream &out, unsigned indent,
-             PrintOptions PO = PrintOptions()) const;
+             const PrintOptions &PO = PrintOptions()) const;
 
   SWIFT_DEBUG_DUMP;
 
diff --git a/include/swift/Sema/ConstraintLocator.h b/include/swift/Sema/ConstraintLocator.h
index 9a6ea1dc05108..3b6052e6df2ef 100644
--- a/include/swift/Sema/ConstraintLocator.h
+++ b/include/swift/Sema/ConstraintLocator.h
@@ -76,12 +76,7 @@ enum ContextualTypePurpose : uint8_t {
   CTP_CaseStmt,         ///< A single case statement associated with a `switch` or
                         ///  a `do-catch` statement. It has to be convertible
                         ///  to a type of a switch subject or an `Error` type.
-  CTP_ForEachStmt,      ///< "expression/sequence" associated with 'for-in' loop
-                        ///< is expected to conform to 'Sequence' protocol.
-  CTP_ForEachSequence,  ///< Sequence expression associated with `for-in` loop,
-                        ///  this element acts slightly differently compared to
-                        ///  \c CTP_ForEachStmt in a sence that it would
-                        ///  produce conformance constraints.
+  CTP_ForEachSequence,  ///< Sequence expression associated with `for-in` loop.
   CTP_WrappedProperty,  ///< Property type expected to match 'wrappedValue' type
   CTP_ComposedPropertyWrapper, ///< Composed wrapper type expected to match
                                ///< former 'wrappedValue' type
@@ -260,6 +255,10 @@ class ConstraintLocator : public llvm::FoldingSetNode {
   /// of the key path at some index.
   bool isKeyPathMemberComponent() const;
 
+  /// Determine whether this locator points to an apply component of the key
+  /// path at some index.
+  bool isKeyPathApplyComponent() const;
+
   /// Determine whether this locator points to the member found
   /// via key path dynamic member lookup.
   bool isForKeyPathDynamicMemberLookup() const;
@@ -1110,7 +1109,7 @@ class LocatorPathElt::SyntacticElement final
 
   Stmt *asStmt() const {
     auto node = ASTNode::getFromOpaqueValue(getStoredPointer());
-    return node.get<Stmt *>();
+    return cast<Stmt *>(node);
   }
 
   static bool classof(const LocatorPathElt *elt) {
diff --git a/include/swift/Sema/ConstraintSystem.h b/include/swift/Sema/ConstraintSystem.h
index c23b4836bf360..929e145baaa47 100644
--- a/include/swift/Sema/ConstraintSystem.h
+++ b/include/swift/Sema/ConstraintSystem.h
@@ -65,6 +65,11 @@ namespace constraints {
 class ConstraintSystem;
 class SyntacticElementTarget;
 
+// PreparedOverload.h
+struct DeclReferenceType;
+class PreparedOverload;
+struct PreparedOverloadBuilder;
+
 } // end namespace constraints
 
 // Forward declare some TypeChecker related functions
@@ -102,9 +107,7 @@ enum class FreeTypeVariableBinding {
   /// Disallow any binding of such free type variables.
   Disallow,
   /// Allow the free type variables to persist in the solution.
-  Allow,
-  /// Bind the type variables to UnresolvedType to represent the ambiguity.
-  UnresolvedType
+  Allow
 };
 
 /// Describes whether or not a result builder method is supported.
@@ -249,6 +252,8 @@ class ExpressionTimer {
   bool PrintWarning;
 
 public:
+  const static unsigned NoLimit = (unsigned) -1;
+
   ExpressionTimer(AnchorType Anchor, ConstraintSystem &CS,
                   unsigned thresholdInSecs);
 
@@ -274,6 +279,9 @@ class ExpressionTimer {
   /// Return the remaining process time in seconds until the
   /// threshold specified during construction is reached.
   unsigned getRemainingProcessTimeInSeconds() const {
+    if (ThresholdInSecs == NoLimit)
+      return NoLimit;
+
     auto elapsed = unsigned(getElapsedProcessTimeInFractionalSeconds());
     return elapsed >= ThresholdInSecs ? 0 : ThresholdInSecs - elapsed;
   }
@@ -407,12 +415,12 @@ class TypeVariableType::Implementation {
   /// is not itself or has a fixed type binding.
   bool hasRepresentativeOrFixed() const {
     // If we have a fixed type, we're done.
-    if (!ParentOrFixed.is<TypeVariableType *>())
+    if (!isa<TypeVariableType *>(ParentOrFixed))
       return true;
 
     // Check whether the representative is different from our own type
     // variable.
-    return ParentOrFixed.get<TypeVariableType *>() != getTypeVariable();
+    return cast<TypeVariableType *>(ParentOrFixed) != getTypeVariable();
   }
 
   /// Low-level accessor; use getRepresentative() or getFixedType() instead.
@@ -488,6 +496,18 @@ class TypeVariableType::Implementation {
   /// literal (represented by `ArrayExpr` and `DictionaryExpr` in AST).
   bool isCollectionLiteralType() const;
 
+  /// Determine whether this type variable represents a literal such
+  /// as an integer value, a floating-point value with and without a sign.
+  bool isNumberLiteralType() const;
+
+  /// Determine whether this type variable represents a result type of a
+  /// function call.
+  bool isFunctionResult() const;
+
+  /// Determine whether this type variable represents a type of the ternary
+  /// operator.
+  bool isTernary() const;
+
   /// Retrieve the representative of the equivalence class to which this
   /// type variable belongs.
   ///
@@ -499,9 +519,9 @@ class TypeVariableType::Implementation {
     // Find the representative type variable.
     auto result = getTypeVariable();
     Implementation *impl = this;
-    while (impl->ParentOrFixed.is<TypeVariableType *>()) {
+    while (isa<TypeVariableType *>(impl->ParentOrFixed)) {
       // Extract the representative.
-      auto nextTV = impl->ParentOrFixed.get<TypeVariableType *>();
+      auto nextTV = cast<TypeVariableType *>(impl->ParentOrFixed);
       if (nextTV == result)
         break;
 
@@ -514,9 +534,9 @@ class TypeVariableType::Implementation {
 
     // Perform path compression.
     impl = this;
-    while (impl->ParentOrFixed.is<TypeVariableType *>()) {
+    while (isa<TypeVariableType *>(impl->ParentOrFixed)) {
       // Extract the representative.
-      auto nextTV = impl->ParentOrFixed.get<TypeVariableType *>();
+      auto nextTV = cast<TypeVariableType *>(impl->ParentOrFixed);
       if (nextTV == result)
         break;
 
@@ -562,6 +582,12 @@ class TypeVariableType::Implementation {
         recordBinding(*trail);
       getTypeVariable()->Bits.TypeVariableType.Options &= ~TVO_CanBindToNoEscape;
     }
+
+    if (canBindToPack() && !otherRep->getImpl().canBindToPack()) {
+      if (trail)
+        recordBinding(*trail);
+      getTypeVariable()->Bits.TypeVariableType.Options &= ~TVO_CanBindToPack;
+    }
   }
 
   /// Retrieve the fixed type that corresponds to this type variable,
@@ -683,7 +709,7 @@ class TypeVariableType::Implementation {
 namespace constraints {
 
 template <typename T = Expr> T *castToExpr(ASTNode node) {
-  return cast<T>(node.get<Expr *>());
+  return cast<T>(cast<Expr *>(node));
 }
 
 template <typename T = Expr> T *getAsExpr(ASTNode node) {
@@ -697,10 +723,10 @@ template <typename T = Expr> T *getAsExpr(ASTNode node) {
 }
 
 template <typename T> bool isExpr(ASTNode node) {
-  if (node.isNull() || !node.is<Expr *>())
+  if (node.isNull() || !isa<Expr *>(node))
     return false;
 
-  auto *E = node.get<Expr *>();
+  auto *E = cast<Expr *>(node);
   return isa<T>(E);
 }
 
@@ -732,7 +758,7 @@ T *getAsPattern(ASTNode node) {
 }
 
 template <typename T = Stmt> T *castToStmt(ASTNode node) {
-  return cast<T>(node.get<Stmt *>());
+  return cast<T>(cast<Stmt *>(node));
 }
 
 SourceLoc getLoc(ASTNode node);
@@ -1651,7 +1677,11 @@ class Solution {
   /// \param wantInterfaceType If true, maps the resulting type out of context,
   /// and replaces type variables for opened generic parameters with the
   /// generic parameter types. Should only be used for diagnostic logic.
-  Type simplifyType(Type type, bool wantInterfaceType = false) const;
+  /// \param forCompletion If true, will produce archetypes instead of
+  /// ErrorTypes for generic parameter originators, which is what completion
+  /// currently expects for the code completion token.
+  Type simplifyType(Type type, bool wantInterfaceType = false,
+                    bool forCompletion = false) const;
 
   // To aid code completion, we need to attempt to convert type placeholders
   // back into underlying generic parameters if possible, since type
@@ -1738,7 +1768,7 @@ class Solution {
   /// Retrieve the overload choice associated with the given
   /// locator.
   SelectedOverload getOverloadChoice(ConstraintLocator *locator) const {
-    return *getOverloadChoiceIfAvailable(locator);
+    return getOverloadChoiceIfAvailable(locator).value();
   }
 
   /// Retrieve the overload choice for the callee associated with the given
@@ -1911,13 +1941,6 @@ enum class ConstraintSystemFlags {
   /// Set if the client wants diagnostics suppressed.
   SuppressDiagnostics = 0x02,
 
-  /// If set, the client wants a best-effort solution to the constraint system,
-  /// but can tolerate a solution where all of the constraints are solved, but
-  /// not all type variables have been determined.  In this case, the constraint
-  /// system is not applied to the expression AST, but the ConstraintSystem is
-  /// left in-tact.
-  AllowUnresolvedTypeVariables = 0x04,
-
   /// If set, verbose output is enabled for this constraint system.
   ///
   /// Note that this flag is automatically applied to all constraint systems,
@@ -1926,12 +1949,12 @@ enum class ConstraintSystemFlags {
   /// \c DebugConstraintSolverAttempt. Finally, it can also be automatically
   /// enabled for a pre-configured set of expressions on line numbers by setting
   /// \c DebugConstraintSolverOnLines.
-  DebugConstraints = 0x08,
+  DebugConstraints = 0x04,
 
   /// If set, we are solving specifically to determine the type of a
   /// CodeCompletionExpr, and should continue in the presence of errors wherever
   /// possible.
-  ForCodeCompletion = 0x10,
+  ForCodeCompletion = 0x08,
 
   /// Include Clang function types when checking equality for function types.
   ///
@@ -1942,13 +1965,16 @@ enum class ConstraintSystemFlags {
   /// should be treated as semantically different, as they may have different
   /// calling conventions, say due to Clang attributes such as
   /// `__attribute__((ns_consumed))`.
-  UseClangFunctionTypes = 0x20,
+  UseClangFunctionTypes = 0x10,
 
   /// When set, ignore async/sync mismatches
-  IgnoreAsyncSyncMismatch = 0x40,
+  IgnoreAsyncSyncMismatch = 0x20,
 
   /// Disable macro expansions.
-  DisableMacroExpansions = 0x80,
+  DisableMacroExpansions = 0x40,
+
+  /// Enable old type-checker performance hacks.
+  EnablePerformanceHacks = 0x80,
 };
 
 /// Options that affect the constraint system as a whole.
@@ -2124,34 +2150,6 @@ struct ClosureIsolatedByPreconcurrency {
   bool operator()(const ClosureExpr *expr) const;
 };
 
-/// Describes the type produced when referencing a declaration.
-struct DeclReferenceType {
-  /// The "opened" type, which is the type of the declaration where any
-  /// generic parameters have been replaced with type variables.
-  ///
-  /// The mapping from generic parameters to type variables will have been
-  /// recorded by \c recordOpenedTypes when this type is produced.
-  Type openedType;
-
-  /// The opened type, after performing contextual type adjustments such as
-  /// removing concurrency-related annotations for a `@preconcurrency`
-  /// operation.
-  Type adjustedOpenedType;
-
-  /// The type of the reference, based on the original opened type. This is the
-  /// type that the expression used to form the declaration reference would
-  /// have if no adjustments had been applied.
-  Type referenceType;
-
-  /// The type of the reference, which is the adjusted opened type after
-  /// (e.g.) applying the base of a member access. This is the type of the
-  /// expression used to form the declaration reference.
-  Type adjustedReferenceType;
-
-  /// The type that could be thrown by accessing this declaration.
-  Type thrownErrorTypeOnAccess;
-};
-
 /// Describes a system of constraints on type variables, the
 /// solution of which assigns concrete types to each of the type variables.
 /// Constraint systems are typically generated given an (untyped) expression.
@@ -2193,6 +2191,8 @@ class ConstraintSystem {
   unsigned CountDisjunctions = 0;
 
 private:
+  bool PreparingOverload = false;
+
   /// A constraint that has failed along the current solver path.
   /// Do not set directly, call \c recordFailedConstraint instead.
   Constraint *failedConstraint = nullptr;
@@ -2398,6 +2398,10 @@ class ConstraintSystem {
   llvm::DenseMap<std::pair<TypeBase *, ProtocolDecl *>, ProtocolConformanceRef>
       Conformances;
 
+  /// A cache for unavailability checks peformed by the solver.
+  llvm::DenseMap<std::pair<const Decl *, ConstraintLocator *>, bool>
+      UnavailableDecls;
+
   /// The list of all generic requirements fixed along the current
   /// solver path.
   using FixedRequirement =
@@ -2734,6 +2738,7 @@ class ConstraintSystem {
   SolverState *solverState = nullptr;
 
   void recordChange(SolverTrail::Change change) {
+    ASSERT(!PreparingOverload);
     solverState->Trail.recordChange(change);
   }
 
@@ -2902,15 +2907,15 @@ class ConstraintSystem {
   SolverTrail *getTrail() const {
     return solverState ? &solverState->Trail : nullptr;
   }
-
-  /// Add a new type variable that was already created.
-  void addTypeVariable(TypeVariableType *typeVar);
   
   /// Add a constraint from the subscript base to the root of the key
   /// path literal to the constraint system.
   void addKeyPathApplicationRootConstraint(Type root, ConstraintLocatorBuilder locator);
 
 public:
+  /// Add a new type variable that was already created.
+  void addTypeVariable(TypeVariableType *typeVar);
+
   /// Lookup for a member with the given name which is in the given base type.
   ///
   /// This routine caches the results of member lookups in the top constraint
@@ -2931,7 +2936,9 @@ class ConstraintSystem {
 
   /// Create a new type variable.
   TypeVariableType *createTypeVariable(ConstraintLocator *locator,
-                                       unsigned options);
+                                       unsigned options,
+                                       PreparedOverloadBuilder *preparedOverload
+                                           = nullptr);
 
   /// Retrieve the set of active type variables.
   ArrayRef<TypeVariableType *> getTypeVariables() const {
@@ -3065,7 +3072,7 @@ class ConstraintSystem {
     return nullptr;
   }
 
-  TypeBase* getFavoredType(Expr *E) {
+  TypeBase *getFavoredType(Expr *E) {
     assert(E != nullptr);
     return this->FavoredTypes[E];
   }
@@ -3079,39 +3086,15 @@ class ConstraintSystem {
   ///
   /// The side tables are used through the expression type checker to avoid
   /// mutating nodes until we know we have successfully type-checked them.
-  void setType(ASTNode node, Type type) {
-    ASSERT(!node.isNull() && "Cannot set type information on null node");
-    ASSERT(type && "Expected non-null type");
-
-    // Record the type.
-    Type &entry = NodeTypes[node];
-    Type oldType = entry;
-    entry = type;
-
-    if (oldType.getPointer() != type.getPointer()) {
-      // Record the fact that we assigned a type to this node.
-      if (solverState)
-        recordChange(SolverTrail::Change::RecordedNodeType(node, oldType));
-    }
-  }
+  void setType(ASTNode node, Type type,
+               PreparedOverloadBuilder *preparedOverload=nullptr);
 
   /// Undo the above change.
-  void restoreType(ASTNode node, Type oldType) {
-    ASSERT(!node.isNull() && "Cannot set type information on null node");
-
-    if (oldType) {
-      auto found = NodeTypes.find(node);
-      ASSERT(found != NodeTypes.end());
-      found->second = oldType;
-    } else {
-      bool erased = NodeTypes.erase(node);
-      ASSERT(erased);
-    }
-  }
+  void restoreType(ASTNode node, Type oldType);
 
   /// Check to see if we have a type for a node.
   bool hasType(ASTNode node) const {
-    assert(!node.isNull() && "Expected non-null node");
+    ASSERT(!node.isNull() && "Expected non-null node");
     return NodeTypes.count(node) > 0;
   }
 
@@ -3119,55 +3102,30 @@ class ConstraintSystem {
   /// map is used throughout the expression type checker in order to
   /// avoid mutating expressions until we know we have successfully
   /// type-checked them.
-  void setType(const KeyPathExpr *KP, unsigned I, Type T) {
-    ASSERT(KP && "Expected non-null key path parameter!");
-    ASSERT(T && "Expected non-null type!");
-
-    Type &entry = KeyPathComponentTypes[{KP, I}];
-    Type oldType = entry;
-    entry = T;
+  void setType(const KeyPathExpr *KP, unsigned I, Type T);
 
-    if (oldType.getPointer() != T.getPointer()) {
-      if (solverState) {
-        recordChange(
-          SolverTrail::Change::RecordedKeyPathComponentType(
-            KP, I, oldType));
-      }
-    }
-  }
-
-  void restoreType(const KeyPathExpr *KP, unsigned I, Type T) {
-    ASSERT(KP && "Expected non-null key path parameter!");
-
-    if (T) {
-      auto found = KeyPathComponentTypes.find({KP, I});
-      ASSERT(found != KeyPathComponentTypes.end());
-      found->second = T;
-    } else {
-      bool erased = KeyPathComponentTypes.erase({KP, I});
-      ASSERT(erased);
-    }
-  }
+  void restoreType(const KeyPathExpr *KP, unsigned I, Type T);
 
   bool hasType(const KeyPathExpr *KP, unsigned I) const {
-    assert(KP && "Expected non-null key path parameter!");
+    ASSERT(KP && "Expected non-null key path parameter!");
     return KeyPathComponentTypes.find(std::make_pair(KP, I))
               != KeyPathComponentTypes.end();
   }
 
   /// Get the type for an node.
   Type getType(ASTNode node) const {
-    assert(hasType(node) && "Expected type to have been set!");
-    // FIXME: lvalue differences
-    //    assert((!E->getType() ||
-    //            E->getType()->isEqual(ExprTypes.find(E)->second)) &&
-    //           "Mismatched types!");
-    return NodeTypes.find(node)->second;
+    ASSERT(!node.isNull() && "Expected non-null node");
+    auto found = NodeTypes.find(node);
+    ASSERT(found != NodeTypes.end() && "Expected type to have been set!");
+    return found->second;
   }
 
   Type getType(const KeyPathExpr *KP, unsigned I) const {
-    assert(hasType(KP, I) && "Expected type to have been set!");
-    return KeyPathComponentTypes.find(std::make_pair(KP, I))->second;
+    ASSERT(KP && "Expected non-null key path parameter!");
+    auto found = KeyPathComponentTypes.find(std::make_pair(KP, I));
+    ASSERT(found != KeyPathComponentTypes.end() &&
+           "Expected type to have been set!");
+    return found->second;
   }
 
   /// Retrieve the type of the node, if known.
@@ -3179,11 +3137,6 @@ class ConstraintSystem {
     return known->second;
   }
 
-  /// Retrieve type of the given declaration to be used in
-  /// constraint system, this is better than calling `getType()`
-  /// directly because it accounts of constraint system flags.
-  Type getVarType(const VarDecl *var);
-
   /// Cache the type of the expression argument and return that same
   /// argument.
   template <typename T>
@@ -3389,7 +3342,9 @@ class ConstraintSystem {
 
   /// Update OpenedExistentials and record a change in the trail.
   void recordOpenedExistentialType(ConstraintLocator *locator,
-                                   ExistentialArchetypeType *opened);
+                                   ExistentialArchetypeType *opened,
+                                   PreparedOverloadBuilder *preparedOverload
+                                      = nullptr);
 
   /// Retrieve the generic environment for the opened element of a given pack
   /// expansion, or \c nullptr if no environment was recorded yet.
@@ -3484,6 +3439,15 @@ class ConstraintSystem {
     return nullptr;
   }
 
+  Expr *getSemanticsProvidingParentExpr(Expr *expr) {
+    while (auto *parent = getParentExpr(expr)) {
+      if (parent->getSemanticsProvidingExpr() == parent)
+        return parent;
+      expr = parent;
+    }
+    return nullptr;
+  }
+
   /// Retrieve the depth of the given expression.
   std::optional<unsigned> getExprDepth(Expr *expr) {
     if (auto result = getExprDepthAndParent(expr))
@@ -3579,9 +3543,16 @@ class ConstraintSystem {
     return Options.contains(ConstraintSystemFlags::ForCodeCompletion);
   }
 
+  /// Check whether old type-checker performance hacks has been explicitly
+  /// enabled.
+  bool performanceHacksEnabled() const {
+    return Options.contains(ConstraintSystemFlags::EnablePerformanceHacks);
+  }
+
   /// Log and record the application of the fix. Return true iff any
   /// subsequent solution would be worse than the best known solution.
-  bool recordFix(ConstraintFix *fix, unsigned impact = 1);
+  bool recordFix(ConstraintFix *fix, unsigned impact = 1,
+                 PreparedOverloadBuilder *preparedOverload = nullptr);
 
   void recordPotentialHole(TypeVariableType *typeVar);
   void recordAnyTypeVarAsPotentialHole(Type type);
@@ -3656,12 +3627,14 @@ class ConstraintSystem {
   /// Add a constraint to the constraint system.
   void addConstraint(ConstraintKind kind, Type first, Type second,
                      ConstraintLocatorBuilder locator,
-                     bool isFavored = false);
+                     bool isFavored = false,
+                     PreparedOverloadBuilder *preparedOverload = nullptr);
 
   /// Add a requirement as a constraint to the constraint system.
   void addConstraint(Requirement req, ConstraintLocatorBuilder locator,
                      bool isFavored,
-                     bool prohibitNonisolatedConformance);
+                     bool prohibitNonisolatedConformance,
+                     PreparedOverloadBuilder *preparedOverload = nullptr);
 
   void addApplicationConstraint(
       FunctionType *appliedFn, Type calleeType,
@@ -3771,9 +3744,9 @@ class ConstraintSystem {
 
   /// Add a constraint that binds an overload set to a specific choice.
   void addBindOverloadConstraint(Type boundTy, OverloadChoice choice,
-                                 ConstraintLocator *locator,
-                                 DeclContext *useDC) {
-    resolveOverload(locator, boundTy, choice, useDC);
+                                 ConstraintLocator *locator, DeclContext *useDC) {
+    resolveOverload(choice, useDC, locator, boundTy,
+                    /*preparedOverload=*/nullptr);
   }
 
   /// Add a value member constraint to the constraint system.
@@ -4275,7 +4248,8 @@ class ConstraintSystem {
   /// \returns The opened type.
   Type openUnboundGenericType(GenericTypeDecl *decl, Type parentTy,
                               ConstraintLocatorBuilder locator,
-                              bool isTypeResolution);
+                              bool isTypeResolution,
+                              PreparedOverloadBuilder *preparedOverload = nullptr);
 
   /// Replace placeholder types with fresh type variables, and unbound generic
   /// types with bound generic types whose generic args are fresh type
@@ -4285,7 +4259,9 @@ class ConstraintSystem {
   ///
   /// \returns The converted type.
   Type replaceInferableTypesWithTypeVars(Type type,
-                                         ConstraintLocatorBuilder locator);
+                                         ConstraintLocatorBuilder locator,
+                                         PreparedOverloadBuilder *preparedOverload
+                                            = nullptr);
 
   /// "Open" the given type by replacing any occurrences of generic
   /// parameter types and dependent member types with fresh type variables.
@@ -4296,7 +4272,8 @@ class ConstraintSystem {
   ///
   /// \returns The opened type, or \c type if there are no archetypes in it.
   Type openType(Type type, ArrayRef<OpenedType> replacements,
-                ConstraintLocatorBuilder locator);
+                ConstraintLocatorBuilder locator,
+                PreparedOverloadBuilder *preparedOverload);
 
   /// "Open" an opaque archetype type, similar to \c openType.
   Type openOpaqueType(OpaqueTypeArchetypeType *type,
@@ -4312,11 +4289,14 @@ class ConstraintSystem {
   /// aforementioned variable via special constraints.
   Type openPackExpansionType(PackExpansionType *expansion,
                              ArrayRef<OpenedType> replacements,
-                             ConstraintLocatorBuilder locator);
+                             ConstraintLocatorBuilder locator,
+                             PreparedOverloadBuilder *preparedOverload);
 
   /// Update OpenedPackExpansionTypes and record a change in the trail.
   void recordOpenedPackExpansionType(PackExpansionType *expansion,
-                                     TypeVariableType *expansionVar);
+                                     TypeVariableType *expansionVar,
+                                     PreparedOverloadBuilder *preparedOverload
+                                        = nullptr);
 
   /// Undo the above change.
   void removeOpenedPackExpansionType(PackExpansionType *expansion) {
@@ -4341,26 +4321,30 @@ class ConstraintSystem {
   FunctionType *openFunctionType(AnyFunctionType *funcType,
                                  ConstraintLocatorBuilder locator,
                                  SmallVectorImpl<OpenedType> &replacements,
-                                 DeclContext *outerDC);
+                                 DeclContext *outerDC,
+                                 PreparedOverloadBuilder *preparedOverload);
 
   /// Open the generic parameter list and its requirements,
   /// creating type variables for each of the type parameters.
   void openGeneric(DeclContext *outerDC,
                    GenericSignature signature,
                    ConstraintLocatorBuilder locator,
-                   SmallVectorImpl<OpenedType> &replacements);
+                   SmallVectorImpl<OpenedType> &replacements,
+                   PreparedOverloadBuilder *preparedOverload);
 
   /// Open the generic parameter list creating type variables for each of the
   /// type parameters.
   void openGenericParameters(DeclContext *outerDC,
                              GenericSignature signature,
                              SmallVectorImpl<OpenedType> &replacements,
-                             ConstraintLocatorBuilder locator);
+                             ConstraintLocatorBuilder locator,
+                             PreparedOverloadBuilder *preparedOverload);
 
   /// Open a generic parameter into a type variable and record
   /// it in \c replacements.
   TypeVariableType *openGenericParameter(GenericTypeParamType *parameter,
-                                         ConstraintLocatorBuilder locator);
+                                         ConstraintLocatorBuilder locator,
+                                         PreparedOverloadBuilder *preparedOverload);
 
   /// Given generic signature open its generic requirements,
   /// using substitution function, and record them in the
@@ -4369,7 +4353,8 @@ class ConstraintSystem {
                                GenericSignature signature,
                                bool skipProtocolSelfConstraint,
                                ConstraintLocatorBuilder locator,
-                               llvm::function_ref<Type(Type)> subst);
+                               llvm::function_ref<Type(Type)> subst,
+                               PreparedOverloadBuilder *preparedOverload);
 
   // Record the given requirement in the constraint system.
   void openGenericRequirement(DeclContext *outerDC,
@@ -4378,17 +4363,20 @@ class ConstraintSystem {
                               const Requirement &requirement,
                               bool skipProtocolSelfConstraint,
                               ConstraintLocatorBuilder locator,
-                              llvm::function_ref<Type(Type)> subst);
+                              llvm::function_ref<Type(Type)> subst,
+                              PreparedOverloadBuilder *preparedOverload);
 
   /// Update OpenedTypes and record a change in the trail.
   void recordOpenedType(
-      ConstraintLocator *locator, ArrayRef<OpenedType> openedTypes);
+      ConstraintLocator *locator, ArrayRef<OpenedType> openedTypes,
+      PreparedOverloadBuilder *preparedOverload = nullptr);
 
   /// Record the set of opened types for the given locator.
   void recordOpenedTypes(
          ConstraintLocatorBuilder locator,
-         SmallVectorImpl<OpenedType> &replacements,
-         bool fixmeAllowDuplicates=false);
+         const SmallVectorImpl<OpenedType> &replacements,
+         PreparedOverloadBuilder *preparedOverload = nullptr,
+         bool fixmeAllowDuplicates = false);
 
   /// Check whether the given type conforms to the given protocol and if
   /// so return a valid conformance reference.
@@ -4399,7 +4387,7 @@ class ConstraintSystem {
   FunctionType *adjustFunctionTypeForConcurrency(
       FunctionType *fnType, Type baseType, ValueDecl *decl, DeclContext *dc,
       unsigned numApplies, bool isMainDispatchQueue,
-      ArrayRef<OpenedType> replacements, ConstraintLocatorBuilder locator);
+      bool openGlobalActorType, ConstraintLocatorBuilder locator);
 
   /// Retrieve the type of a reference to the given value declaration.
   ///
@@ -4407,39 +4395,10 @@ class ConstraintSystem {
   /// the type by replacing each instance of an archetype with a fresh type
   /// variable.
   ///
-  /// \param decl The declarations whose type is being computed.
-  ///
   /// \returns a description of the type of this declaration reference.
   DeclReferenceType getTypeOfReference(
-                          ValueDecl *decl,
-                          FunctionRefInfo functionRefInfo,
-                          ConstraintLocatorBuilder locator,
-                          DeclContext *useDC);
-
-  /// Return the type-of-reference of the given value.
-  ///
-  /// \param baseType if non-null, return the type of a member reference to
-  ///   this value when the base has the given type
-  ///
-  /// \param UseDC The context of the access.  Some variables have different
-  ///   types depending on where they are used.
-  ///
-  /// \param locator The locator anchored at this value reference, when
-  /// it is a member reference.
-  ///
-  /// \param wantInterfaceType Whether we want the interface type, if available.
-  Type getUnopenedTypeOfReference(VarDecl *value, Type baseType,
-                                  DeclContext *UseDC,
-                                  ConstraintLocator *locator,
-                                  bool wantInterfaceType = false,
-                                  bool adjustForPreconcurrency = true);
-
-  /// Given the opened type and a pile of information about a member reference,
-  /// determine the reference type of the member reference.
-  Type getMemberReferenceTypeFromOpenedType(
-      Type &openedType, Type baseObjTy, ValueDecl *value, DeclContext *outerDC,
-      ConstraintLocator *locator, bool hasAppliedSelf, bool isDynamicLookup,
-      ArrayRef<OpenedType> replacements);
+      OverloadChoice choice, DeclContext *useDC, ConstraintLocatorBuilder locator,
+      PreparedOverloadBuilder *preparedOverload);
 
   /// Retrieve the type of a reference to the given value declaration,
   /// as a member with a base of the given type.
@@ -4448,14 +4407,10 @@ class ConstraintSystem {
   /// this routine "opens up" the type by replacing each instance of a generic
   /// parameter with a fresh type variable.
   ///
-  /// \param isDynamicLookup Indicates that this declaration was found via
-  /// dynamic lookup.
-  ///
   /// \returns a description of the type of this declaration reference.
   DeclReferenceType getTypeOfMemberReference(
-      Type baseTy, ValueDecl *decl, DeclContext *useDC, bool isDynamicLookup,
-      FunctionRefInfo functionRefInfo, ConstraintLocator *locator,
-      SmallVectorImpl<OpenedType> *replacements = nullptr);
+      OverloadChoice choice, DeclContext *useDC, ConstraintLocator *locator,
+      PreparedOverloadBuilder *preparedOverload);
 
   /// Retrieve a list of generic parameter types solver has "opened" (replaced
   /// with a type variable) at the given location.
@@ -4467,6 +4422,56 @@ class ConstraintSystem {
   }
 
 private:
+  /// \returns The opened type and the thrown error type.
+  std::pair<Type, Type> getTypeOfReferencePre(
+       OverloadChoice choice, DeclContext *useDC, ConstraintLocatorBuilder locator,
+       PreparedOverloadBuilder *preparedOverload);
+
+  DeclReferenceType getTypeOfReferencePost(
+       OverloadChoice choice, DeclContext *useDC, ConstraintLocatorBuilder locator,
+       Type openedType, Type thrownErrorType);
+
+  /// \returns the opened type and the thrown error type.
+  std::pair<Type, Type> getTypeOfMemberReferencePre(
+      OverloadChoice choice, DeclContext *useDC, ConstraintLocator *locator,
+      PreparedOverloadBuilder *preparedOverload);
+
+  DeclReferenceType getTypeOfMemberReferencePost(
+      OverloadChoice choice, DeclContext *useDC, ConstraintLocator *locator,
+      Type openedType, Type thrownErrorType);
+
+  Type getTypeOfMemberTypeReference(
+      Type baseObjTy, TypeDecl *typeDecl, ConstraintLocator *locator,
+      PreparedOverloadBuilder *preparedOverload);
+
+  /// Return the type-of-reference of the given value.
+  ///
+  /// \param baseType if non-null, return the type of a member reference to
+  ///   this value when the base has the given type
+  ///
+  /// \param UseDC The context of the access.  Some variables have different
+  ///   types depending on where they are used.
+  ///
+  /// \param locator The locator anchored at this value reference, when
+  /// it is a member reference.
+  ///
+  /// \param wantInterfaceType Whether we want the interface type, if available.
+  Type getUnopenedTypeOfReference(VarDecl *value, Type baseType,
+                                  DeclContext *UseDC,
+                                  ConstraintLocator *locator,
+                                  bool wantInterfaceType);
+
+  std::pair<Type, Type> getOpenedStorageType(
+      Type baseTy, AbstractStorageDecl *value, DeclContext *useDC,
+      bool hasAppliedSelf, ArrayRef<OpenedType> replacements,
+      ConstraintLocator *locator, PreparedOverloadBuilder *preparedOverload);
+
+  /// Given the opened type and a pile of information about a member reference,
+  /// determine the reference type of the member reference.
+  Type getMemberReferenceTypeFromOpenedType(
+      Type type, Type baseObjTy, ValueDecl *value,
+      ConstraintLocator *locator, bool hasAppliedSelf, bool isDynamicLookup);
+
   /// Add the constraints needed to bind an overload's type variable.
   void bindOverloadType(const SelectedOverload &overload, Type boundType,
                         ConstraintLocator *locator, DeclContext *useDC);
@@ -4868,9 +4873,33 @@ class ConstraintSystem {
   void recordResolvedOverload(ConstraintLocator *locator,
                               SelectedOverload choice);
 
+  /// Build and allocate a prepared overload in the solver arena.
+  PreparedOverload *prepareOverload(OverloadChoice choice,
+                                    DeclContext *useDC,
+                                    ConstraintLocator *locator);
+
+  /// Populate the prepared overload with all type variables and constraints
+  /// that are to be introduced into the constraint system when this choice
+  /// is taken.
+  ///
+  /// Returns a pair consisting of the opened type, and the thrown error type.
+  ///
+  /// FIXME: As a transitional mechanism, if preparedOverload is nullptr, this
+  /// immediately performs all operations.
+  std::pair<Type, Type>
+  prepareOverloadImpl(OverloadChoice choice,
+                      DeclContext *useDC,
+                      ConstraintLocator *locator,
+                      PreparedOverloadBuilder *preparedOverload);
+
+  void replayChanges(
+      ConstraintLocator *locator,
+      PreparedOverload *preparedOverload);
+
   /// Resolve the given overload set to the given choice.
-  void resolveOverload(ConstraintLocator *locator, Type boundType,
-                       OverloadChoice choice, DeclContext *useDC);
+  void resolveOverload(OverloadChoice choice, DeclContext *useDC,
+                       ConstraintLocator *locator, Type boundType,
+                       PreparedOverload *preparedOverload);
 
   /// Simplify a type, by replacing type variables with either their
   /// fixed types (if available) or their representatives.
@@ -5274,13 +5303,20 @@ class ConstraintSystem {
   /// Matches a wrapped or projected value parameter type to its backing
   /// property wrapper type by applying the property wrapper.
   TypeMatchResult applyPropertyWrapperToParameter(
-      Type wrapperType, Type paramType, ParamDecl *param, Identifier argLabel,
-      ConstraintKind matchKind, ConstraintLocator *locator,
-      ConstraintLocator *calleeLocator);
+      Type wrapperType,
+      Type paramType,
+      ParamDecl *param,
+      Identifier argLabel,
+      ConstraintKind matchKind,
+      ConstraintLocator *locator,
+      ConstraintLocator *calleeLocator,
+      PreparedOverloadBuilder *preparedOverload = nullptr);
 
   /// Used by applyPropertyWrapperToParameter() to update appliedPropertyWrappers
   /// and record a change in the trail.
-  void applyPropertyWrapper(Expr *anchor, AppliedPropertyWrapper applied);
+  void applyPropertyWrapper(Expr *anchor,
+                            AppliedPropertyWrapper applied,
+                            PreparedOverloadBuilder *preparedOverload = nullptr);
 
   /// Undo the above change.
   void removePropertyWrapper(Expr *anchor);
@@ -5378,8 +5414,12 @@ class ConstraintSystem {
 
   /// Pick a disjunction from the InactiveConstraints list.
   ///
-  /// \returns The selected disjunction.
-  Constraint *selectDisjunction();
+  /// \returns The selected disjunction and a set of it's favored choices.
+  std::optional<std::pair<Constraint *, llvm::TinyPtrVector<Constraint *>>>
+  selectDisjunction();
+
+  /// The old method that is only used when performance hacks are enabled.
+  Constraint *selectDisjunctionWithHacks();
 
   /// Pick a conjunction from the InactiveConstraints list.
   ///
@@ -5594,13 +5634,22 @@ class ConstraintSystem {
     if (CancellationFlag && CancellationFlag->load(std::memory_order_relaxed))
       return true;
 
+    auto markTooComplex = [&](SourceRange range, StringRef reason) {
+      if (isDebugMode()) {
+        if (solverState)
+          llvm::errs().indent(solverState->getCurrentIndent());
+        llvm::errs() << "(too complex: " << reason << ")\n";
+      }
+      isAlreadyTooComplex = {true, range};
+      return true;
+    };
+
     auto used = getASTContext().getSolverMemory() + solutionMemory;
     MaxMemory = std::max(used, MaxMemory);
     auto threshold = getASTContext().TypeCheckerOpts.SolverMemoryThreshold;
     if (MaxMemory > threshold) {
       // No particular location for OoM problems.
-      isAlreadyTooComplex.first = true;
-      return true;
+      return markTooComplex(SourceRange(), "exceeded memory limit");
     }
 
     if (Timer && Timer->isExpired()) {
@@ -5609,23 +5658,18 @@ class ConstraintSystem {
       // emitting an error.
       Timer->disableWarning();
 
-      isAlreadyTooComplex = {true, Timer->getAffectedRange()};
-      return true;
+      return markTooComplex(Timer->getAffectedRange(), "exceeded time limit");
     }
 
     auto &opts = getASTContext().TypeCheckerOpts;
 
     // Bail out once we've looked at a really large number of choices.
-    if (opts.SolverScopeThreshold && NumSolverScopes > opts.SolverScopeThreshold) {
-      isAlreadyTooComplex.first = true;
-      return true;
-    }
+    if (opts.SolverScopeThreshold && NumSolverScopes > opts.SolverScopeThreshold)
+      return markTooComplex(SourceRange(), "exceeded scope limit");
 
     // Bail out once we've taken a really large number of steps.
-    if (opts.SolverTrailThreshold && NumTrailSteps > opts.SolverTrailThreshold) {
-      isAlreadyTooComplex.first = true;
-      return true;
-    }
+    if (opts.SolverTrailThreshold && NumTrailSteps > opts.SolverTrailThreshold)
+      return markTooComplex(SourceRange(), "exceeded trail limit");
 
     return false;
   }
@@ -5659,7 +5703,7 @@ class ConstraintSystem {
 
   /// If we aren't certain that we've emitted a diagnostic, emit a fallback
   /// diagnostic.
-  void maybeProduceFallbackDiagnostic(SyntacticElementTarget target) const;
+  void maybeProduceFallbackDiagnostic(SourceLoc loc) const;
 
   /// Check whether given AST node represents an argument of an application
   /// of some sort (call, operator invocation, subscript etc.)
@@ -5723,6 +5767,23 @@ class OpenUnboundGenericType {
   }
 };
 
+/// A function object suitable for use as an \c OpenRequirementFn that "opens"
+/// the requirements for a given type's generic signature given a set of
+/// argument substitutions.
+class OpenGenericTypeRequirements {
+  ConstraintSystem &cs;
+  const ConstraintLocatorBuilder &locator;
+  PreparedOverloadBuilder *preparedOverload;
+
+public:
+  explicit OpenGenericTypeRequirements(
+      ConstraintSystem &cs, const ConstraintLocatorBuilder &locator,
+      PreparedOverloadBuilder *preparedOverload)
+      : cs(cs), locator(locator), preparedOverload(preparedOverload) {}
+
+  void operator()(GenericTypeDecl *decl, TypeSubstitutionFn subst) const;
+};
+
 class HandlePlaceholderType {
   ConstraintSystem &cs;
   ConstraintLocator *locator;
@@ -6019,6 +6080,7 @@ bool isAutoClosureArgument(Expr *argExpr);
 /// parameter being applied, meaning that it's dropped from the type of the
 /// reference.
 bool hasAppliedSelf(ConstraintSystem &cs, const OverloadChoice &choice);
+bool hasAppliedSelf(const Solution &S, const OverloadChoice &choice);
 bool hasAppliedSelf(const OverloadChoice &choice,
                     llvm::function_ref<Type(Type)> getFixedType);
 
@@ -6079,6 +6141,12 @@ class DisjunctionChoice {
     return false;
   }
 
+  bool isDisfavored() const {
+    if (auto *decl = getOverloadChoiceDecl(Choice))
+      return decl->getAttrs().hasAttribute<DisfavoredOverloadAttr>();
+    return false;
+  }
+
   bool isBeginningOfPartition() const { return IsBeginningOfPartition; }
 
   // FIXME: All three of the accessors below are required to support
@@ -6159,8 +6227,7 @@ class TypeVariableBinding {
   fixForHole(ConstraintSystem &cs) const;
 
   void print(llvm::raw_ostream &Out, SourceManager *, unsigned indent) const {
-    PrintOptions PO;
-    PO.PrintTypesForDebugging = true;
+    PrintOptions PO = PrintOptions::forDebugging();
     Out << "type variable binding " << TypeVar->getString(PO)
         << " := " << Binding.BindingType->getString(PO);
   }
@@ -6313,7 +6380,8 @@ class DisjunctionChoiceProducer : public BindingProducer<DisjunctionChoice> {
 public:
   using Element = DisjunctionChoice;
 
-  DisjunctionChoiceProducer(ConstraintSystem &cs, Constraint *disjunction)
+  DisjunctionChoiceProducer(ConstraintSystem &cs, Constraint *disjunction,
+                            llvm::TinyPtrVector<Constraint *> &favorites)
       : BindingProducer(cs, disjunction->shouldRememberChoice()
                                 ? disjunction->getLocator()
                                 : nullptr),
@@ -6323,6 +6391,11 @@ class DisjunctionChoiceProducer : public BindingProducer<DisjunctionChoice> {
     assert(disjunction->getKind() == ConstraintKind::Disjunction);
     assert(!disjunction->shouldRememberChoice() || disjunction->getLocator());
 
+    // Mark constraints as favored. This information
+    // is going to be used by partitioner.
+    for (auto *choice : favorites)
+      cs.favorConstraint(choice);
+
     // Order and partition the disjunction choices.
     partitionDisjunction(Ordering, PartitionBeginning);
   }
@@ -6367,8 +6440,9 @@ class DisjunctionChoiceProducer : public BindingProducer<DisjunctionChoice> {
   // Partition the choices in the disjunction into groups that we will
   // iterate over in an order appropriate to attempt to stop before we
   // have to visit all of the options.
-  void partitionDisjunction(SmallVectorImpl<unsigned> &Ordering,
-                            SmallVectorImpl<unsigned> &PartitionBeginning);
+  void
+  partitionDisjunction(SmallVectorImpl<unsigned> &Ordering,
+                       SmallVectorImpl<unsigned> &PartitionBeginning);
 
   /// Partition the choices in the range \c first to \c last into groups and
   /// order the groups in the best order to attempt based on the argument
@@ -6455,10 +6529,6 @@ class TypeVarRefCollector : public ASTWalker {
   }
 };
 
-/// Determine whether given type is a known one
-/// for a key path `{Any, Partial, Writable, ReferenceWritable}KeyPath`.
-bool isKnownKeyPathType(Type type);
-
 /// Determine whether the given type is a PartialKeyPath and
 /// AnyKeyPath or existential type thererof, for example,
 /// `PartialKeyPath<...> & Sendable`.
@@ -6656,12 +6726,6 @@ bool isSIMDOperator(ValueDecl *value);
 
 std::string describeGenericType(ValueDecl *GP, bool includeName = false);
 
-/// Whether the given parameter requires an argument.
-bool parameterRequiresArgument(
-    ArrayRef<AnyFunctionType::Param> params,
-    const ParameterListInfo &paramInfo,
-    unsigned paramIdx);
-
 } // end namespace swift
 
 namespace llvm {
diff --git a/include/swift/Sema/IDETypeChecking.h b/include/swift/Sema/IDETypeChecking.h
index 97464ca523722..57a888fbcdea9 100644
--- a/include/swift/Sema/IDETypeChecking.h
+++ b/include/swift/Sema/IDETypeChecking.h
@@ -140,22 +140,6 @@ namespace swift {
   bool typeCheckASTNodeAtLoc(TypeCheckASTNodeAtLocContext TypeCheckCtx,
                              SourceLoc TargetLoc);
 
-  /// Thunk around \c TypeChecker::typeCheckForCodeCompletion to make it
-  /// available to \c swift::ide.
-  /// Type check the given expression and provide results back to code
-  /// completion via specified callback.
-  ///
-  /// This method is designed to be used for code completion which means that
-  /// it doesn't mutate given expression, even if there is a single valid
-  /// solution, and constraint solver is allowed to produce partially correct
-  /// solutions. Such solutions can have any number of holes in them.
-  ///
-  /// \returns `true` if target was applicable and it was possible to infer
-  /// types for code completion, `false` otherwise.
-  bool typeCheckForCodeCompletion(
-      constraints::SyntacticElementTarget &target, bool needsPrecheck,
-      llvm::function_ref<void(const constraints::Solution &)> callback);
-
   /// Thunk around \c TypeChecker::resolveDeclRefExpr to make it available to
   /// \c swift::ide
   Expr *resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE, DeclContext *Context);
@@ -197,7 +181,7 @@ namespace swift {
     Implementation &Impl;
   public:
     SynthesizedExtensionAnalyzer(NominalTypeDecl *Target,
-                                 PrintOptions Options,
+                                 PrintOptions &&Options,
                                  bool IncludeUnconditional = true);
     ~SynthesizedExtensionAnalyzer();
 
diff --git a/include/swift/Sema/OverloadChoice.h b/include/swift/Sema/OverloadChoice.h
index 111703be8f50e..e1b4f0643b2f4 100644
--- a/include/swift/Sema/OverloadChoice.h
+++ b/include/swift/Sema/OverloadChoice.h
@@ -126,20 +126,19 @@ class OverloadChoice {
   /// FIXME: This needs three bits. Can we pack them somewhere?
   FunctionRefInfo TheFunctionRefInfo = FunctionRefInfo::unappliedBaseName();
 
-public:
-  OverloadChoice() : BaseAndDeclKind(nullptr, 0), DeclOrKind() {}
-
   OverloadChoice(Type base, ValueDecl *value,
                  FunctionRefInfo functionRefInfo)
     : BaseAndDeclKind(base, 0),
       TheFunctionRefInfo(functionRefInfo) {
-    assert(!base || !base->hasTypeParameter());
     assert((reinterpret_cast<uintptr_t>(value) & (uintptr_t)0x03) == 0 &&
            "Badly aligned decl");
     
     DeclOrKind = value;
   }
 
+public:
+  OverloadChoice() : BaseAndDeclKind(nullptr, 0), DeclOrKind() {}
+
   OverloadChoice(Type base, OverloadChoiceKind kind)
       : BaseAndDeclKind(base, 0), DeclOrKind(uint32_t(kind)) {
     assert(base && "Must have a base type for overload choice");
@@ -162,6 +161,22 @@ class OverloadChoice {
            BaseAndDeclKind.getInt() == 0 && DeclOrKind.isNull();
   }
 
+  /// Retrieve an overload choice for a declaration that was found via
+  /// unqualified lookup.
+  static OverloadChoice getDecl(ValueDecl *value,
+                                FunctionRefInfo functionRefInfo) {
+    return OverloadChoice(Type(), value, functionRefInfo);
+  }
+
+
+  /// Retrieve an overload choice for a declaration that was found via
+  /// qualified lookup.
+  static OverloadChoice getDecl(Type base, ValueDecl *value,
+                                FunctionRefInfo functionRefInfo) {
+    ASSERT(!base->hasTypeParameter());
+    return OverloadChoice(base, value, functionRefInfo);
+  }
+
   /// Retrieve an overload choice for a declaration that was found via
   /// dynamic lookup.
   static OverloadChoice getDeclViaDynamic(Type base, ValueDecl *value,
@@ -232,8 +247,8 @@ class OverloadChoice {
                  ? OverloadChoiceKind::KeyPathDynamicMemberLookup
                  : OverloadChoiceKind::DynamicMemberLookup;
     }
-    
-    if (DeclOrKind.is<ValueDecl*>()) {
+
+    if (isa<ValueDecl *>(DeclOrKind)) {
       switch (BaseAndDeclKind.getInt()) {
       case IsDeclViaBridge: return OverloadChoiceKind::DeclViaBridge;
       case IsDeclViaDynamic: return OverloadChoiceKind::DeclViaDynamic;
@@ -243,22 +258,35 @@ class OverloadChoice {
       default: return OverloadChoiceKind::Decl;
       }
     }
-    uint32_t kind = DeclOrKind.get<OverloadChoiceKindWithTupleIndex>();
+    uint32_t kind = cast<OverloadChoiceKindWithTupleIndex>(DeclOrKind);
     if (kind >= (uint32_t)OverloadChoiceKind::TupleIndex)
       return OverloadChoiceKind::TupleIndex;
 
     return (OverloadChoiceKind)kind;
   }
 
-  /// Determine whether this choice is for a declaration.
-  bool isDecl() const {
-    return DeclOrKind.is<ValueDecl*>();
+  bool canBePrepared() const {
+    switch (getKind()) {
+    case OverloadChoiceKind::Decl:
+    case OverloadChoiceKind::DeclViaBridge:
+    case OverloadChoiceKind::DeclViaDynamic:
+    case OverloadChoiceKind::DeclViaUnwrappedOptional:
+    case OverloadChoiceKind::DynamicMemberLookup:
+    case OverloadChoiceKind::KeyPathDynamicMemberLookup:
+      return true;
+    case OverloadChoiceKind::TupleIndex:
+    case OverloadChoiceKind::MaterializePack:
+    case OverloadChoiceKind::ExtractFunctionIsolation:
+    case OverloadChoiceKind::KeyPathApplication:
+      return false;
+    }
   }
 
+  /// Determine whether this choice is for a declaration.
+  bool isDecl() const { return isa<ValueDecl *>(DeclOrKind); }
+
   /// Retrieve the declaration that corresponds to this overload choice.
-  ValueDecl *getDecl() const {
-    return DeclOrKind.get<ValueDecl*>();
-  }
+  ValueDecl *getDecl() const { return cast<ValueDecl *>(DeclOrKind); }
 
   /// Retrieves the declaration that corresponds to this overload choice, or
   /// \c nullptr if this choice is not for a declaration.
@@ -295,7 +323,7 @@ class OverloadChoice {
   /// choice.
   unsigned getTupleIndex() const {
     assert(getKind() == OverloadChoiceKind::TupleIndex);
-    uint32_t kind = DeclOrKind.get<OverloadChoiceKindWithTupleIndex>();
+    uint32_t kind = cast<OverloadChoiceKindWithTupleIndex>(DeclOrKind);
     return kind-(uint32_t)OverloadChoiceKind::TupleIndex;
   }
 
diff --git a/include/swift/Sema/PreparedOverload.h b/include/swift/Sema/PreparedOverload.h
new file mode 100644
index 0000000000000..de316eb988b1d
--- /dev/null
+++ b/include/swift/Sema/PreparedOverload.h
@@ -0,0 +1,265 @@
+//===--- PreparedOverload.h - A Choice from an Overload Set  ----*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+#ifndef SWIFT_SEMA_PREPAREDOVERLOAD_H
+#define SWIFT_SEMA_PREPAREDOVERLOAD_H
+
+#include "swift/AST/PropertyWrappers.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/PointerIntPair.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/TrailingObjects.h"
+
+namespace swift {
+
+class ExistentialArchetypeType;
+class GenericTypeParamType;
+class TypeVariableType;
+
+namespace constraints {
+
+class ConstraintLocatorBuilder;
+class ConstraintSystem;
+
+/// Describes the type produced when referencing a declaration.
+struct DeclReferenceType {
+  /// The "opened" type, which is the type of the declaration where any
+  /// generic parameters have been replaced with type variables.
+  ///
+  /// The mapping from generic parameters to type variables will have been
+  /// recorded by \c recordOpenedTypes when this type is produced.
+  Type openedType;
+
+  /// The opened type, after performing contextual type adjustments such as
+  /// removing concurrency-related annotations for a `@preconcurrency`
+  /// operation.
+  Type adjustedOpenedType;
+
+  /// The type of the reference, based on the original opened type. This is the
+  /// type that the expression used to form the declaration reference would
+  /// have if no adjustments had been applied.
+  Type referenceType;
+
+  /// The type of the reference, which is the adjusted opened type after
+  /// (e.g.) applying the base of a member access. This is the type of the
+  /// expression used to form the declaration reference.
+  Type adjustedReferenceType;
+
+  /// The type that could be thrown by accessing this declaration.
+  Type thrownErrorTypeOnAccess;
+};
+
+/// Describes a dependent type that has been opened to a particular type
+/// variable.
+using OpenedType = std::pair<GenericTypeParamType *, TypeVariableType *>;
+
+/// A change to be introduced into the constraint system when this
+/// overload choice is chosen.
+struct PreparedOverloadChange {
+  enum ChangeKind : unsigned {
+    /// A generic parameter was opened to a type variable.
+    AddedTypeVariable,
+
+    /// A generic requirement was opened to a constraint.
+    AddedConstraint,
+
+    /// Special case of a Bind constraint.
+    AddedBindConstraint,
+
+    /// A mapping of generic parameter types to type variables
+    /// was recorded.
+    OpenedTypes,
+
+    /// An existential type was opened.
+    OpenedExistentialType,
+
+    /// A pack expansion type was opened.
+    OpenedPackExpansionType,
+
+    /// A property wrapper was applied to a parameter.
+    AppliedPropertyWrapper,
+
+    /// A fix was recorded because a property wrapper application failed.
+    AddedFix,
+
+    /// The type of an AST node was changed.
+    RecordedNodeType
+  };
+
+  /// The kind of change.
+  ChangeKind Kind;
+
+  union {
+    /// For ChangeKind::AddedTypeVariable.
+    TypeVariableType *TypeVar;
+
+    /// For ChangeKind::AddedConstraint.
+    Constraint *TheConstraint;
+
+    struct {
+      TypeBase *FirstType;
+      TypeBase * SecondType;
+    } Bind;
+
+    /// For ChangeKind::OpenedTypes.
+    struct {
+      const OpenedType *Data;
+      size_t Count;
+    } Replacements;
+
+    /// For ChangeKind::OpenedExistentialType.
+    ExistentialArchetypeType *TheExistential;
+
+    /// For ChangeKind::OpenedPackExpansionType.
+    struct {
+      PackExpansionType *TheExpansion;
+      TypeVariableType *TypeVar;
+    } PackExpansion;
+
+    /// For ChangeKind::AppliedPropertyWrapper.
+    struct {
+      TypeBase *WrapperType;
+      PropertyWrapperInitKind InitKind;
+    } PropertyWrapper;
+
+    /// For ChangeKind::Fix.
+    struct {
+      ConstraintFix *TheFix;
+      unsigned Impact;
+    } Fix;
+
+    /// For ChangeKind::RecordedNodeType.
+    struct {
+      ASTNode Node;
+      Type TheType;
+    } Node;
+  };
+
+  PreparedOverloadChange()
+      : Kind(ChangeKind::AddedTypeVariable),
+        TypeVar(nullptr) { }
+};
+
+/// A "pre-cooked" representation of all type variables and constraints
+/// that are generated as part of an overload choice.
+class PreparedOverload final :
+  public llvm::TrailingObjects<PreparedOverload, PreparedOverloadChange> {
+
+public:
+  using Change = PreparedOverloadChange;
+
+private:
+  Type OpenedType;
+  Type ThrownErrorType;
+  size_t Count;
+
+  size_t numTrailingObjects(OverloadToken<Change>) const {
+    return Count;
+  }
+
+public:
+  PreparedOverload(Type openedType, Type thrownErrorType,
+                   ArrayRef<Change> changes)
+    : OpenedType(openedType), ThrownErrorType(thrownErrorType),
+      Count(changes.size()) {
+    std::uninitialized_copy(changes.begin(), changes.end(),
+                            getTrailingObjects());
+  }
+
+  Type getOpenedType() const {
+    return OpenedType;
+  }
+
+  Type getThrownErrorType() const {
+    return ThrownErrorType;
+  }
+
+  ArrayRef<Change> getChanges() const { return getTrailingObjects(Count); }
+};
+
+struct PreparedOverloadBuilder {
+  SmallVector<PreparedOverload::Change, 8> Changes;
+
+  void addedTypeVariable(TypeVariableType *typeVar) {
+    PreparedOverload::Change change;
+    change.Kind = PreparedOverload::Change::AddedTypeVariable;
+    change.TypeVar = typeVar;
+    Changes.push_back(change);
+  }
+
+  void addedConstraint(Constraint *constraint) {
+    PreparedOverload::Change change;
+    change.Kind = PreparedOverload::Change::AddedConstraint;
+    change.TheConstraint = constraint;
+    Changes.push_back(change);
+  }
+
+  void addedBindConstraint(Type firstType, Type secondType) {
+    PreparedOverload::Change change;
+    change.Kind = PreparedOverload::Change::AddedBindConstraint;
+    change.Bind.FirstType = firstType.getPointer();
+    change.Bind.SecondType = secondType.getPointer();
+    Changes.push_back(change);
+  }
+
+  void openedTypes(ArrayRef<OpenedType> replacements) {
+    PreparedOverload::Change change;
+    change.Kind = PreparedOverload::Change::OpenedTypes;
+    change.Replacements.Data = replacements.data();
+    change.Replacements.Count = replacements.size();
+    Changes.push_back(change);
+  }
+
+  void openedExistentialType(ExistentialArchetypeType *openedExistential) {
+    PreparedOverload::Change change;
+    change.Kind = PreparedOverload::Change::OpenedExistentialType;
+    change.TheExistential = openedExistential;
+    Changes.push_back(change);
+  }
+
+  void openedPackExpansionType(PackExpansionType *packExpansion,
+                               TypeVariableType *typeVar) {
+    PreparedOverload::Change change;
+    change.Kind = PreparedOverload::Change::OpenedPackExpansionType;
+    change.PackExpansion.TheExpansion = packExpansion;
+    change.PackExpansion.TypeVar = typeVar;
+    Changes.push_back(change);
+  }
+
+  void appliedPropertyWrapper(AppliedPropertyWrapper wrapper) {
+    PreparedOverload::Change change;
+    change.Kind = PreparedOverload::Change::AppliedPropertyWrapper;
+    change.PropertyWrapper.WrapperType = wrapper.wrapperType.getPointer();
+    change.PropertyWrapper.InitKind = wrapper.initKind;
+    Changes.push_back(change);
+  }
+
+  void addedFix(ConstraintFix *fix, unsigned impact) {
+    PreparedOverload::Change change;
+    change.Kind = PreparedOverload::Change::AddedFix;
+    change.Fix.TheFix = fix;
+    change.Fix.Impact = impact;
+    Changes.push_back(change);
+  }
+
+  void recordedNodeType(ASTNode node, Type type) {
+    PreparedOverload::Change change;
+    change.Kind = PreparedOverload::Change::RecordedNodeType;
+    change.Node.Node = node;
+    change.Node.TheType = type;
+    Changes.push_back(change);
+  }
+};
+
+}  // end namespace constraints
+}  // end namespace swift
+
+#endif
diff --git a/include/swift/Sema/SourceLoader.h b/include/swift/Sema/SourceLoader.h
index ae908c21be9d2..c0f24f82a23e6 100644
--- a/include/swift/Sema/SourceLoader.h
+++ b/include/swift/Sema/SourceLoader.h
@@ -24,20 +24,17 @@ class ModuleDecl;
 class SourceLoader : public ModuleLoader {
 private:
   ASTContext &Ctx;
-  bool EnableLibraryEvolution;
+  std::vector<ModuleDecl *> ModulesToBindExtensions;
 
   explicit SourceLoader(ASTContext &ctx,
-                        bool enableResilience,
                         DependencyTracker *tracker)
-    : ModuleLoader(tracker), Ctx(ctx),
-      EnableLibraryEvolution(enableResilience) {}
+    : ModuleLoader(tracker), Ctx(ctx) {}
 
 public:
   static std::unique_ptr<SourceLoader>
-  create(ASTContext &ctx, bool enableResilience,
-         DependencyTracker *tracker = nullptr) {
+  create(ASTContext &ctx, DependencyTracker *tracker = nullptr) {
     return std::unique_ptr<SourceLoader>{
-      new SourceLoader(ctx, enableResilience, tracker)
+      new SourceLoader(ctx, tracker)
     };
   }
 
@@ -97,14 +94,6 @@ class SourceLoader : public ModuleLoader {
   {
     // Parsing populates the Objective-C method tables.
   }
-
-  llvm::SmallVector<std::pair<ModuleDependencyID, ModuleDependencyInfo>, 1>
-  getModuleDependencies(Identifier moduleName, StringRef moduleOutputPath, StringRef sdkModuleOutputPath,
-                        const llvm::DenseSet<clang::tooling::dependencies::ModuleID> &alreadySeenClangModules,
-                        clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-                        InterfaceSubContextDelegate &delegate,
-                        llvm::PrefixMapper *mapper,
-                        bool isTestableImport) override;
 };
 }
 
diff --git a/include/swift/Sema/SyntacticElementTarget.h b/include/swift/Sema/SyntacticElementTarget.h
index 2a138d7920dbb..47d084bf2bb98 100644
--- a/include/swift/Sema/SyntacticElementTarget.h
+++ b/include/swift/Sema/SyntacticElementTarget.h
@@ -10,7 +10,8 @@
 //
 //===----------------------------------------------------------------------===//
 //
-//  This file defines the SyntacticElementTarget class.
+//  This file defines the SyntacticElementTarget class (a unit of
+//  type-checking).
 //
 //===----------------------------------------------------------------------===//
 
@@ -59,8 +60,8 @@ struct PackIterationInfo {
 /// within the constraint system.
 using ForEachStmtInfo = TaggedUnion<SequenceIterationInfo, PackIterationInfo>;
 
-/// Describes the target to which a constraint system's solution can be
-/// applied.
+/// Describes the target (a unit of type-checking) to which a constraint
+/// system's solution can be applied.
 class SyntacticElementTarget {
 public:
   enum class Kind {
@@ -262,8 +263,9 @@ class SyntacticElementTarget {
                     unsigned patternBindingIndex, bool bindPatternVarsOneWay);
 
   /// Form an expression target for a ReturnStmt.
-  static SyntacticElementTarget
-  forReturn(ReturnStmt *returnStmt, Type contextTy, DeclContext *dc);
+  static SyntacticElementTarget forReturn(ReturnStmt *returnStmt,
+                                          Expr *returnExpr, Type contextTy,
+                                          DeclContext *dc);
 
   /// Form a target for the preamble of a for-in loop, excluding its where
   /// clause and body.
@@ -450,7 +452,7 @@ class SyntacticElementTarget {
   /// For a pattern initialization target, retrieve the pattern.
   Pattern *getInitializationPattern() const {
     if (kind == Kind::uninitializedVar)
-      return uninitializedVar.declaration.get<Pattern *>();
+      return cast<Pattern *>(uninitializedVar.declaration);
 
     assert(isForInitialization());
     return expression.pattern;
@@ -589,7 +591,7 @@ class SyntacticElementTarget {
 
   void setPattern(Pattern *pattern) {
     if (kind == Kind::uninitializedVar) {
-      assert(uninitializedVar.declaration.is<Pattern *>());
+      assert(isa<Pattern *>(uninitializedVar.declaration));
       uninitializedVar.declaration = pattern;
       return;
     }
@@ -601,7 +603,6 @@ class SyntacticElementTarget {
 
     switch (getExprContextualTypePurpose()) {
     case CTP_Initialization:
-    case CTP_ForEachStmt:
     case CTP_ForEachSequence:
     case CTP_ExprPattern:
       break;
@@ -833,7 +834,7 @@ class SyntacticElementTarget {
               uninitializedVar.declaration.dyn_cast<VarDecl *>()) {
         return wrappedVar->getSourceRange();
       }
-      return uninitializedVar.declaration.get<Pattern *>()->getSourceRange();
+      return cast<Pattern *>(uninitializedVar.declaration)->getSourceRange();
     }
 
     // For-in preamble target doesn't cover the body.
@@ -877,7 +878,7 @@ class SyntacticElementTarget {
               uninitializedVar.declaration.dyn_cast<VarDecl *>()) {
         return wrappedVar->getLoc();
       }
-      return uninitializedVar.declaration.get<Pattern *>()->getLoc();
+      return cast<Pattern *>(uninitializedVar.declaration)->getLoc();
     }
 
     case Kind::forEachPreamble:
diff --git a/include/swift/Serialization/ScanningLoaders.h b/include/swift/Serialization/ScanningLoaders.h
index 42d58bdac8cee..709ade4521666 100644
--- a/include/swift/Serialization/ScanningLoaders.h
+++ b/include/swift/Serialization/ScanningLoaders.h
@@ -18,45 +18,43 @@
 #include "swift/Serialization/SerializedModuleLoader.h"
 
 namespace swift {
+
+/// Result of looking up a Swift module on the current filesystem
+/// search paths.
+struct SwiftModuleScannerQueryResult {
+  struct IncompatibleCandidate {
+    std::string path;
+    std::string incompatibilityReason;
+  };
+
+  SwiftModuleScannerQueryResult()
+      : foundDependencyInfo(std::nullopt), incompatibleCandidates() {}
+
+  SwiftModuleScannerQueryResult(
+      std::optional<ModuleDependencyInfo> &&dependencyInfo,
+      std::vector<IncompatibleCandidate> &&candidates)
+      : foundDependencyInfo(dependencyInfo),
+        incompatibleCandidates(candidates) {}
+
+  std::optional<ModuleDependencyInfo> foundDependencyInfo;
+  std::vector<IncompatibleCandidate> incompatibleCandidates;
+};
+
 /// A module "loader" that looks for .swiftinterface and .swiftmodule files
 /// for the purpose of determining dependencies, but does not attempt to
 /// load the module files.
 class SwiftModuleScanner : public SerializedModuleLoaderBase {
-public:
-  enum ScannerKind { MDS_plain, MDS_placeholder };
-
 private:
-  /// The kind of scanner this is (LLVM-style RTTI)
-  const ScannerKind kind;
-
-  /// The module we're scanning dependencies of.
-  Identifier moduleName;
-
   /// Scan the given interface file to determine dependencies.
   llvm::ErrorOr<ModuleDependencyInfo>
-  scanInterfaceFile(Twine moduleInterfacePath, bool isFramework,
-                    bool isTestableImport);
+  scanInterfaceFile(Identifier moduleID, Twine moduleInterfacePath,
+                    bool isFramework, bool isTestableImport);
 
-  InterfaceSubContextDelegate &astDelegate;
-
-  /// Location where pre-built modules are to be built into.
-  std::string moduleOutputPath;
-  /// Location where pre-built SDK modules are to be built into.
-  std::string sdkModuleOutputPath;
-
-public:
-  std::optional<ModuleDependencyInfo> dependencies;
-
-  SwiftModuleScanner(ASTContext &ctx, ModuleLoadingMode LoadMode,
-                     Identifier moduleName,
-                     InterfaceSubContextDelegate &astDelegate,
-                     StringRef moduleOutputPath, StringRef sdkModuleOutputPath,
-                     ScannerKind kind = MDS_plain)
-      : SerializedModuleLoaderBase(ctx, nullptr, LoadMode,
-                                   /*IgnoreSwiftSourceInfoFile=*/true),
-        kind(kind), moduleName(moduleName), astDelegate(astDelegate),
-        moduleOutputPath(moduleOutputPath),
-        sdkModuleOutputPath(sdkModuleOutputPath) {}
+  /// Scan the given serialized module file to determine dependencies.
+  llvm::ErrorOr<ModuleDependencyInfo>
+  scanBinaryModuleFile(Identifier moduleID, Twine binaryModulePath,
+                       bool isFramework, bool isTestableImport,
+                       bool isCandidateForTextualModule);
 
   std::error_code findModuleFilesInDirectory(
       ImportPath::Element ModuleID, const SerializedModuleBaseName &BaseName,
@@ -65,64 +63,54 @@ class SwiftModuleScanner : public SerializedModuleLoaderBase {
       std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-      bool SkipBuildingInterface, bool IsFramework,
+      bool IsCanImportLookup, bool IsFramework,
       bool IsTestableDependencyLookup) override;
 
+  bool canImportModule(ImportPath::Module named, SourceLoc loc,
+                       ModuleVersionInfo *versionInfo,
+                       bool isTestableImport) override;
+
+  bool handlePossibleTargetMismatch(
+      SourceLoc sourceLocation,
+      StringRef moduleName,
+      const SerializedModuleBaseName &BaseName,
+      bool isCanImportLookup) override;
+
   virtual void collectVisibleTopLevelModuleNames(
       SmallVectorImpl<Identifier> &names) const override {
     llvm_unreachable("Not used");
   }
 
-  ScannerKind getKind() const { return kind; }
-  static bool classof(const SwiftModuleScanner *MDS) {
-    return MDS->getKind() == MDS_plain;
-  }
-};
-
-/// A ModuleLoader that loads placeholder dependency module stubs specified in
-/// -placeholder-dependency-module-map-file
-/// This loader is used only in dependency scanning to inform the scanner that a
-/// set of modules constitute placeholder dependencies that are not visible to
-/// the scanner but will nevertheless be provided by the scanner's clients. This
-/// "loader" will not attempt to load any module files.
-class PlaceholderSwiftModuleScanner : public SwiftModuleScanner {
-  /// Scan the given placeholder module map
-  void parsePlaceholderModuleMap(StringRef fileName);
-
-  llvm::StringMap<ExplicitSwiftModuleInputInfo> PlaceholderDependencyModuleMap;
-  llvm::BumpPtrAllocator Allocator;
-
+  /// AST delegate to be used for textual interface scanning
+  InterfaceSubContextDelegate &astDelegate;
+  /// Clang-specific (-Xcc) command-line flags to include on
+  /// Swift module compilation commands
+  std::vector<std::string> swiftModuleClangCC1CommandLineArgs;
+  /// Module inputs specified with -swift-module-input,
+  /// <ModuleName, Path to .swiftmodule file>
+  llvm::StringMap<std::string> explicitSwiftModuleInputs;
+
+  /// Constituents of a result of a given Swift module query,
+  /// reset at the end of every query.
+  std::optional<ModuleDependencyInfo> foundDependencyInfo;
+  std::vector<SwiftModuleScannerQueryResult::IncompatibleCandidate>
+      incompatibleCandidates;
 public:
-  PlaceholderSwiftModuleScanner(ASTContext &ctx, ModuleLoadingMode LoadMode,
-                                Identifier moduleName,
-                                StringRef PlaceholderDependencyModuleMap,
-                                InterfaceSubContextDelegate &astDelegate,
-                                StringRef moduleOutputPath,
-                                StringRef sdkModuleOutputPath)
-      : SwiftModuleScanner(ctx, LoadMode, moduleName, astDelegate,
-                           moduleOutputPath, sdkModuleOutputPath,
-                           MDS_placeholder) {
-
-    // FIXME: Find a better place for this map to live, to avoid
-    // doing the parsing on every module.
-    if (!PlaceholderDependencyModuleMap.empty()) {
-      parsePlaceholderModuleMap(PlaceholderDependencyModuleMap);
-    }
+  SwiftModuleScanner(
+      ASTContext &ctx, ModuleLoadingMode LoadMode,
+      InterfaceSubContextDelegate &astDelegate,
+      std::vector<std::string> swiftModuleClangCC1CommandLineArgs,
+      llvm::StringMap<std::string> &explicitSwiftModuleInputs)
+      : SerializedModuleLoaderBase(ctx, nullptr, LoadMode,
+                                   /*IgnoreSwiftSourceInfoFile=*/true),
+        astDelegate(astDelegate),
+        swiftModuleClangCC1CommandLineArgs(swiftModuleClangCC1CommandLineArgs),
+        explicitSwiftModuleInputs(explicitSwiftModuleInputs) {
   }
 
-  virtual bool
-  findModule(ImportPath::Element moduleID,
-             SmallVectorImpl<char> *moduleInterfacePath,
-             SmallVectorImpl<char> *moduleInterfaceSourcePath,
-             std::unique_ptr<llvm::MemoryBuffer> *moduleBuffer,
-             std::unique_ptr<llvm::MemoryBuffer> *moduleDocBuffer,
-             std::unique_ptr<llvm::MemoryBuffer> *moduleSourceInfoBuffer,
-             bool skipBuildingInterface, bool isTestableDependencyLookup,
-             bool &isFramework, bool &isSystemModule) override;
-
-  static bool classof(const SwiftModuleScanner *MDS) {
-    return MDS->getKind() == MDS_placeholder;
-  }
+  /// Perform a filesystem search for a Swift module with a given name
+  SwiftModuleScannerQueryResult lookupSwiftModule(Identifier moduleName,
+                                                  bool isTestableImport);
 };
 } // namespace swift
 
diff --git a/include/swift/Serialization/SerializationOptions.h b/include/swift/Serialization/SerializationOptions.h
index 8ef9109a9a9d3..19d2a96ffada5 100644
--- a/include/swift/Serialization/SerializationOptions.h
+++ b/include/swift/Serialization/SerializationOptions.h
@@ -162,7 +162,6 @@ class SerializationOptions {
   bool StaticLibrary = false;
   bool HermeticSealAtLink = false;
   bool EmbeddedSwiftModule = false;
-  bool IsOSSA = false;
   bool SkipNonExportableDecls = false;
   bool ExplicitModuleBuild = false;
   bool EnableSerializationRemarks = false;
diff --git a/include/swift/Serialization/SerializedModuleLoader.h b/include/swift/Serialization/SerializedModuleLoader.h
index 0337f035643a7..c137370177bdf 100644
--- a/include/swift/Serialization/SerializedModuleLoader.h
+++ b/include/swift/Serialization/SerializedModuleLoader.h
@@ -103,7 +103,7 @@ class SerializedModuleLoaderBase : public ModuleLoader {
       std::unique_ptr<llvm::MemoryBuffer> *moduleBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *moduleDocBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *moduleSourceInfoBuffer,
-      bool skipBuildingInterface, bool isTestableDependencyLookup,
+      bool isCanImportLookup, bool isTestableDependencyLookup,
       bool &isFramework, bool &isSystemModule);
 
   /// Attempts to search the provided directory for a loadable serialized
@@ -125,8 +125,8 @@ class SerializedModuleLoaderBase : public ModuleLoader {
       std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-      bool SkipBuildingInterface, bool IsFramework,
-      bool isTestableDependencyLookup = false) = 0;
+      bool IsCanImportLookup, bool IsFramework,
+      bool IsTestableDependencyLookup = false) = 0;
 
   std::error_code
   openModuleFile(
@@ -151,27 +151,31 @@ class SerializedModuleLoaderBase : public ModuleLoader {
   /// to list the architectures that \e are present.
   ///
   /// \returns true if an error diagnostic was emitted
-  virtual bool maybeDiagnoseTargetMismatch(
+  virtual bool handlePossibleTargetMismatch(
       SourceLoc sourceLocation,
       StringRef moduleName,
-      const SerializedModuleBaseName &BaseName) {
+      const SerializedModuleBaseName &baseName,
+      bool isCanImportLookup) {
     return false;
   }
 
+  /// Assuming the \c baseName is a target-specific Swift module path,
+  /// for a missing target variant, collect all adjacent binary module
+  /// files to build a list of discovered modules for incompatible
+  /// architectures.
+  static void identifyArchitectureVariants(
+       ASTContext &Ctx,
+       const SerializedModuleBaseName &baseName,
+       std::vector<std::string> &incompatibleArchModules);
+
   /// Determines if the provided path is a cached artifact for dependency
   /// tracking purposes.
   virtual bool isCached(StringRef DepPath) {
     return false;
   }
 
-  /// Scan the given serialized module file to determine dependencies.
-  llvm::ErrorOr<ModuleDependencyInfo>
-  scanModuleFile(Twine modulePath, bool isFramework,
-                 bool isTestableImport, bool isCandidateForTextualModule);
-
   struct BinaryModuleImports {
-    llvm::StringSet<> moduleImports;
-    llvm::StringSet<> exportedModules;
+    std::vector<ScannerImportStatementInfo> moduleImports;
     std::string headerImport;
   };
 
@@ -189,8 +193,8 @@ class SerializedModuleLoaderBase : public ModuleLoader {
   static llvm::ErrorOr<std::vector<ScannerImportStatementInfo>>
   getMatchingPackageOnlyImportsOfModule(Twine modulePath,
                                         bool isFramework,
-                                        bool isRequiredOSSAModules,
                                         StringRef SDKName,
+                                        const llvm::Triple &target,
                                         StringRef packageName,
                                         llvm::vfs::FileSystem *fileSystem,
                                         PathObfuscator &recoverer);
@@ -217,8 +221,6 @@ class SerializedModuleLoaderBase : public ModuleLoader {
           std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
           bool isFramework);
 
-  bool isRequiredOSSAModules() const;
-
   /// Check whether the module with a given name can be imported without
   /// importing it.
   ///
@@ -263,14 +265,6 @@ class SerializedModuleLoaderBase : public ModuleLoader {
 
   virtual void verifyAllModules() override;
 
-  virtual llvm::SmallVector<std::pair<ModuleDependencyID, ModuleDependencyInfo>, 1>
-  getModuleDependencies(Identifier moduleName, StringRef moduleOutputPath, StringRef sdkModuleOutputPath,
-                        const llvm::DenseSet<clang::tooling::dependencies::ModuleID> &alreadySeenClangModules,
-                        clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-                        InterfaceSubContextDelegate &delegate,
-                        llvm::PrefixMapper *mapper,
-                        bool isTestableImport) override;
-
   /// A textual reason why the compiler rejected a binary module load
   /// attempt with a given status, to be used for diagnostic output.
   static std::optional<std::string> invalidModuleReason(serialization::Status status);
@@ -291,13 +285,14 @@ class ImplicitSerializedModuleLoader : public SerializedModuleLoaderBase {
       std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-      bool SkipBuildingInterface, bool IsFramework,
-      bool isTestableDependencyLookup = false) override;
+      bool IsCanImportLookup, bool IsFramework,
+      bool IsTestableDependencyLookup = false) override;
 
-  bool maybeDiagnoseTargetMismatch(
+  bool handlePossibleTargetMismatch(
       SourceLoc sourceLocation,
       StringRef moduleName,
-      const SerializedModuleBaseName &BaseName) override;
+      const SerializedModuleBaseName &BaseName,
+      bool isCanImportLookup) override;
 
 public:
   virtual ~ImplicitSerializedModuleLoader();
@@ -349,14 +344,9 @@ class MemoryBufferSerializedModuleLoader : public SerializedModuleLoaderBase {
       std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
       std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-      bool SkipBuildingInterface, bool IsFramework,
+      bool IsCanImportLookup, bool IsFramework,
       bool IsTestableDependencyLookup = false) override;
 
-  bool maybeDiagnoseTargetMismatch(
-      SourceLoc sourceLocation,
-      StringRef moduleName,
-      const SerializedModuleBaseName &BaseName) override;
-
   bool BypassResilience;
 public:
   virtual ~MemoryBufferSerializedModuleLoader();
@@ -479,6 +469,9 @@ class SerializedASTFile final : public LoadedFile {
                 const ModuleDecl *importedModule,
                 llvm::SmallSetVector<Identifier, 4> &spiGroups) const override;
 
+  virtual bool isModuleImportedPreconcurrency(
+      const ModuleDecl *importedModule) const override;
+
   std::optional<CommentInfo> getCommentForDecl(const Decl *D) const override;
 
   bool hasLoadedSwiftDoc() const override;
@@ -580,15 +573,16 @@ class SerializedASTFile final : public LoadedFile {
 bool extractCompilerFlagsFromInterface(
     StringRef interfacePath, StringRef buffer, llvm::StringSaver &ArgSaver,
     SmallVectorImpl<const char *> &SubArgs,
-    std::optional<llvm::Triple> PreferredTarget = std::nullopt);
+    std::optional<llvm::Triple> PreferredTarget = std::nullopt,
+    DiagnosticEngine *diagEngine = nullptr);
 
 /// Extract the user module version number from an interface file.
 llvm::VersionTuple extractUserModuleVersionFromInterface(StringRef moduleInterfacePath);
 
 /// Extract embedded bridging header from binary module.
-std::string
+std::unique_ptr<llvm::MemoryBuffer>
 extractEmbeddedBridgingHeaderContent(std::unique_ptr<llvm::MemoryBuffer> file,
-                                     ASTContext &Context);
+                                     StringRef headerPath, ASTContext &Context);
 } // end namespace swift
 
 #endif
diff --git a/include/swift/Serialization/Validation.h b/include/swift/Serialization/Validation.h
index 545e1900dd4c6..e01254c48b183 100644
--- a/include/swift/Serialization/Validation.h
+++ b/include/swift/Serialization/Validation.h
@@ -23,10 +23,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-
-namespace llvm {
-class Triple;
-}
+#include "llvm/TargetParser/Triple.h"
 
 namespace swift {
 
@@ -54,9 +51,6 @@ enum class Status {
   /// The distribution channel doesn't match.
   ChannelIncompatible,
 
-  /// The module is required to be in OSSA, but is not.
-  NotInOSSA,
-
   /// The module file depends on another module that can't be loaded.
   MissingDependency,
 
@@ -150,7 +144,7 @@ class ExtendedValidationInfo {
     unsigned AllowNonResilientAccess: 1;
     unsigned SerializePackageEnabled: 1;
     unsigned StrictMemorySafety: 1;
-    unsigned SupportsExtensibleEnums : 1;
+    unsigned DeferredCodeGen: 1;
   } Bits;
 
 public:
@@ -255,7 +249,14 @@ class ExtendedValidationInfo {
   void setStrictMemorySafety(bool val = true) {
     Bits.StrictMemorySafety = val;
   }
-  
+
+  bool deferredCodeGen() const {
+    return Bits.DeferredCodeGen;
+  }
+  void setDeferredCodeGen(bool val = true) {
+    Bits.DeferredCodeGen = val;
+  }
+
   bool hasCxxInteroperability() const { return Bits.HasCxxInteroperability; }
   void setHasCxxInteroperability(bool val) {
     Bits.HasCxxInteroperability = val;
@@ -272,11 +273,6 @@ class ExtendedValidationInfo {
             version, SourceLoc(), /*Diags=*/nullptr))
       SwiftInterfaceCompilerVersion = genericVersion.value();
   }
-
-  bool supportsExtensibleEnums() const { return Bits.SupportsExtensibleEnums; }
-  void setSupportsExtensibleEnums(bool val) {
-    Bits.SupportsExtensibleEnums = val;
-  }
 };
 
 struct SearchPath {
@@ -298,22 +294,23 @@ struct SearchPath {
 ///
 /// \param data A buffer containing the serialized AST. Result information
 /// refers directly into this buffer.
-/// \param requiresOSSAModules If true, necessitates the module to be
-/// compiled with -enable-ossa-modules.
 /// \param requiredSDK If not empty, only accept modules built with
 /// a compatible SDK. The StringRef represents the canonical SDK name.
+/// \param target The target triple of the current compilation for
+/// validating that the module we are attempting to load is compatible.
 /// \param[out] extendedInfo If present, will be populated with additional
 /// compilation options serialized into the AST at build time that may be
 /// necessary to load it properly.
 /// \param[out] dependencies If present, will be populated with list of
 /// input files the module depends on, if present in INPUT_BLOCK.
 ValidationInfo validateSerializedAST(
-    StringRef data, bool requiresOSSAModules,
+    StringRef data,
     StringRef requiredSDK,
     ExtendedValidationInfo *extendedInfo = nullptr,
     SmallVectorImpl<SerializationOptions::FileDependency> *dependencies =
         nullptr,
-    SmallVectorImpl<SearchPath> *searchPaths = nullptr);
+    SmallVectorImpl<SearchPath> *searchPaths = nullptr,
+    std::optional<llvm::Triple> target = std::nullopt);
 
 /// Emit diagnostics explaining a failure to load a serialized AST.
 ///
diff --git a/include/swift/StaticMirror/ObjectFileContext.h b/include/swift/StaticMirror/ObjectFileContext.h
index 5c259eb40e73a..5b53b3670aa82 100644
--- a/include/swift/StaticMirror/ObjectFileContext.h
+++ b/include/swift/StaticMirror/ObjectFileContext.h
@@ -39,8 +39,12 @@ class Image {
   uint64_t HeaderAddress;
   std::vector<Segment> Segments;
   struct DynamicRelocation {
+    /// The symbol name that the pointer refers to. Empty if only an absolute
+    /// address is available.
     StringRef Symbol;
-    uint64_t Offset;
+    // The offset (if the symbol is available), or the resolved remote address
+    // if the symbol is empty.
+    uint64_t OffsetOrAddress;
   };
   llvm::DenseMap<uint64_t, DynamicRelocation> DynamicRelocations;
 
@@ -53,6 +57,8 @@ class Image {
 
   void scanCOFF(const llvm::object::COFFObjectFile *O);
 
+  void scanWasm(const llvm::object::WasmObjectFile *O);
+
   bool isMachOWithPtrAuth() const;
 
 public:
@@ -88,14 +94,19 @@ class ObjectMemoryReader : public reflection::MemoryReader {
   };
   std::vector<ImageEntry> Images;
 
+  uint64_t PtrauthMask = 0;
+
   std::pair<const Image *, uint64_t>
   decodeImageIndexAndAddress(uint64_t Addr) const;
 
-  uint64_t encodeImageIndexAndAddress(const Image *image,
-                                      uint64_t imageAddr) const;
+  remote::RemoteAddress
+  encodeImageIndexAndAddress(const Image *image,
+                             remote::RemoteAddress imageAddr) const;
 
   StringRef getContentsAtAddress(uint64_t Addr, uint64_t Size);
 
+  uint64_t getPtrauthMask();
+
 public:
   explicit ObjectMemoryReader(
       const std::vector<const llvm::object::ObjectFile *> &ObjectFiles);
@@ -110,7 +121,7 @@ class ObjectMemoryReader : public reflection::MemoryReader {
   // TODO: We could consult the dynamic symbol tables of the images to
   // implement this.
   reflection::RemoteAddress getSymbolAddress(const std::string &name) override {
-    return reflection::RemoteAddress(nullptr);
+    return reflection::RemoteAddress();
   }
 
   ReadBytesResult readBytes(reflection::RemoteAddress Addr,
diff --git a/include/swift/Subsystems.h b/include/swift/Subsystems.h
index 134c3b636d3d5..635c306601c54 100644
--- a/include/swift/Subsystems.h
+++ b/include/swift/Subsystems.h
@@ -126,8 +126,7 @@ namespace swift {
   /// Resolve imports for a source file generated to adapt a given
   /// Clang module.
   void performImportResolutionForClangMacroBuffer(
-    SourceFile &SF, ModuleDecl *clangModule
-  );
+      SourceFile &SF, ModuleDecl *explicitOriginModule);
 
   /// Once type-checking is complete, this instruments code with calls to an
   /// intrinsic that record the expected values of local variables so they can
diff --git a/include/swift/SwiftRemoteMirror/Platform.h b/include/swift/SwiftRemoteMirror/Platform.h
index 587d49e419571..eb666c3506159 100644
--- a/include/swift/SwiftRemoteMirror/Platform.h
+++ b/include/swift/SwiftRemoteMirror/Platform.h
@@ -23,20 +23,16 @@ extern "C" {
 # elif defined(__MACH__)
 #   define SWIFT_REMOTE_MIRROR_LINKAGE __attribute__((__visibility__("default")))
 # else
-#   if defined(_WINDLL)
-#     define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllexport)
-#   else
-#     define SWIFT_REMOTE_MIRROR_LINKAGE
-#   endif
+#   define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllexport)
 # endif
 #else
 # if defined(__ELF__) || defined(__MACH__) || defined(__WASM__)
 #   define SWIFT_REMOTE_MIRROR_LINKAGE __attribute__((__visibility__("default")))
 # else
-#   if defined(_WINDLL)
-#     define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllimport)
-#   else
+#   if defined(swiftRemoteMirror_STATIC)
 #     define SWIFT_REMOTE_MIRROR_LINKAGE
+#   else
+#     define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllimport)
 #   endif
 # endif
 #endif
diff --git a/include/swift/SymbolGraphGen/SymbolGraphOptions.h b/include/swift/SymbolGraphGen/SymbolGraphOptions.h
index 168e345d4c4e3..179c2c142ded9 100644
--- a/include/swift/SymbolGraphGen/SymbolGraphOptions.h
+++ b/include/swift/SymbolGraphGen/SymbolGraphOptions.h
@@ -10,8 +10,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/TargetParser/Triple.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/TargetParser/Triple.h"
 
 #include "swift/AST/AttrKind.h"
 
@@ -69,6 +70,13 @@ struct SymbolGraphOptions {
   /// If this has a value specifies an explicit allow list of reexported module
   /// names that should be included symbol graph.
   std::optional<llvm::ArrayRef<StringRef>> AllowedReexportedModules = {};
+
+  /// If set, a list of availability platforms to restrict (or block) when
+  /// rendering symbol graphs.
+  std::optional<llvm::DenseSet<StringRef>> AvailabilityPlatforms = {};
+
+  /// Whether `AvailabilityPlatforms` is an allow list or a block list.
+  bool AvailabilityIsBlockList = false;
 };
 
 } // end namespace symbolgraphgen
diff --git a/include/swift/Threading/Impl/Darwin.h b/include/swift/Threading/Impl/Darwin.h
index 24a0f71ec4709..2cb48dc0bfff7 100644
--- a/include/swift/Threading/Impl/Darwin.h
+++ b/include/swift/Threading/Impl/Darwin.h
@@ -131,7 +131,9 @@ inline void lazy_mutex_unsafe_unlock(lazy_mutex_handle &handle) {
 
 // .. Recursive mutex support .................................................
 
-// The os_unfair_recursive_lock interface is stable, but not in the SDK. Bring
+#if OS_LOCK_API_VERSION < 20250601
+
+// The os_unfair_recursive_lock interface is stable, but not in this SDK. Bring
 // our own definitions for what we need.
 
 #define OS_UNFAIR_RECURSIVE_LOCK_INIT                                          \
@@ -142,8 +144,6 @@ typedef struct os_unfair_recursive_lock_s {
   uint32_t ourl_count;
 } os_unfair_recursive_lock, *os_unfair_recursive_lock_t;
 
-using recursive_mutex_handle = os_unfair_recursive_lock;
-
 extern "C" void
 os_unfair_recursive_lock_lock_with_options(os_unfair_recursive_lock_t lock,
                                            uint32_t options);
@@ -151,6 +151,10 @@ os_unfair_recursive_lock_lock_with_options(os_unfair_recursive_lock_t lock,
 extern "C" void
 os_unfair_recursive_lock_unlock(os_unfair_recursive_lock_t lock);
 
+#endif // OS_UNFAIR_RECURSIVE_LOCK_INIT
+
+using recursive_mutex_handle = os_unfair_recursive_lock;
+
 inline void recursive_mutex_init(recursive_mutex_handle &handle,
                                  bool checked = false) {
   handle = OS_UNFAIR_RECURSIVE_LOCK_INIT;
diff --git a/lib/APIDigester/CMakeLists.txt b/lib/APIDigester/CMakeLists.txt
index 29d23d1223e7a..1fa0c63c2fc8f 100644
--- a/lib/APIDigester/CMakeLists.txt
+++ b/lib/APIDigester/CMakeLists.txt
@@ -7,4 +7,10 @@ add_swift_host_library(swiftAPIDigester STATIC
 target_link_libraries(swiftAPIDigester PRIVATE
   swiftIDE)
 
+# Clang dependencies. These are private because APIDigester's public
+# interface does not use Clang symbols.
+target_link_libraries(swiftAPIDigester PRIVATE
+  clangAST
+  clangLex)
+
 set_swift_llvm_is_available(swiftAPIDigester)
diff --git a/lib/APIDigester/ModuleAnalyzerNodes.cpp b/lib/APIDigester/ModuleAnalyzerNodes.cpp
index bbc0cb5e61ab1..59ee7d4ed0f83 100644
--- a/lib/APIDigester/ModuleAnalyzerNodes.cpp
+++ b/lib/APIDigester/ModuleAnalyzerNodes.cpp
@@ -3,6 +3,8 @@
 #include "swift/Basic/Defer.h"
 #include "swift/Parse/Lexer.h"
 #include "swift/Sema/IDETypeChecking.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/Lex/Preprocessor.h"
 #include "llvm/ADT/STLExtras.h"
 #include <algorithm>
 #include <swift/APIDigester/ModuleAnalyzerNodes.h>
@@ -752,7 +754,7 @@ SDKNode* SDKNode::constructSDKNode(SDKContext &Ctx,
         AccessorKind unknownKind = (AccessorKind)((uint8_t)(AccessorKind::Last) + 1);
         Info.AccKind = llvm::StringSwitch<AccessorKind>(
           GetScalarString(Pair.getValue()))
-#define ACCESSOR(ID)
+#define ACCESSOR(ID, KEYWORD)
 #define SINGLETON_ACCESSOR(ID, KEYWORD) .Case(#KEYWORD, AccessorKind::ID)
 #include "swift/AST/AccessorKinds.def"
           .Default(unknownKind);
@@ -1063,10 +1065,11 @@ static StringRef getPrintedName(SDKContext &Ctx, Type Ty,
   llvm::raw_string_ostream OS(S);
   PrintOptions PO = getTypePrintOpts(Ctx.getOpts());
   PO.SkipAttributes = true;
+  NonRecursivePrintOptions OPO;
   if (IsImplicitlyUnwrappedOptional)
-    PO.PrintOptionalAsImplicitlyUnwrapped = true;
+    OPO |= NonRecursivePrintOption::ImplicitlyUnwrappedOptional;
 
-  Ty.print(OS, PO);
+  Ty.print(OS, PO, OPO);
   return Ctx.buffer(OS.str());
 }
 
@@ -1165,8 +1168,9 @@ static StringRef getSimpleName(ValueDecl *VD) {
   }
   if (auto *AD = dyn_cast<AccessorDecl>(VD)) {
     switch(AD->getAccessorKind()) {
-#define ACCESSOR(ID) \
-case AccessorKind::ID: return #ID;
+#define ACCESSOR(ID, KEYWORD)                                                  \
+    case AccessorKind::ID:                                                     \
+      return #ID;
 #include "swift/AST/AccessorKinds.def"
     }
   }
@@ -1376,7 +1380,7 @@ StringRef SDKContext::getLanguageIntroVersion(Decl *D) {
   for (auto attr : D->getSemanticAvailableAttrs()) {
     auto domain = attr.getDomain();
 
-    if (domain.isSwiftLanguage() && attr.getIntroduced()) {
+    if (domain.isSwiftLanguageMode() && attr.getIntroduced()) {
       return buffer(attr.getIntroduced()->getAsString());
     }
   }
@@ -1984,7 +1988,7 @@ SwiftDeclCollector::addConformancesToTypeDecl(SDKNodeDeclType *Root,
   } else {
     // Avoid adding the same conformance twice.
     SmallPtrSet<ProtocolConformance*, 4> Seen;
-    for (auto &Conf: NTD->getAllConformances()) {
+    for (auto &Conf: NTD->getAllConformances(/*sorted=*/true)) {
       if (!Ctx.shouldIgnore(Conf->getProtocol()) && !Seen.count(Conf))
         Root->addConformance(constructConformanceNode(Conf));
       Seen.insert(Conf);
@@ -2267,7 +2271,7 @@ struct ScalarEnumerationTraits<DeclKind> {
 template<>
 struct ScalarEnumerationTraits<AccessorKind> {
   static void enumeration(Output &out, AccessorKind &value) {
-#define ACCESSOR(ID)
+#define ACCESSOR(ID, KEYWORD)
 #define SINGLETON_ACCESSOR(ID, KEYWORD) \
   out.enumCase(value, #KEYWORD, AccessorKind::ID);
 #include "swift/AST/AccessorKinds.def"
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 002a7fc1ec098..99c229c1c4557 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -520,7 +520,7 @@ struct ASTContext::Implementation {
   llvm::DenseMap<const AbstractFunctionDecl *, SourceRange> OriginalBodySourceRanges;
 
   /// Macro discriminators per context.
-  llvm::DenseMap<std::pair<const void *, Identifier>, unsigned>
+  llvm::DenseMap<std::pair<const void *, DeclBaseName>, unsigned>
       NextMacroDiscriminator;
 
   /// Local and closure discriminators per context.
@@ -567,6 +567,7 @@ struct ASTContext::Implementation {
     llvm::DenseMap<Type, ExistentialType *> ExistentialTypes;
     llvm::FoldingSet<UnboundGenericType> UnboundGenericTypes;
     llvm::FoldingSet<BoundGenericType> BoundGenericTypes;
+    llvm::FoldingSet<BuiltinFixedArrayType> BuiltinFixedArrayTypes;
     llvm::FoldingSet<ProtocolCompositionType> ProtocolCompositionTypes;
     llvm::FoldingSet<ParameterizedProtocolType> ParameterizedProtocolTypes;
     llvm::FoldingSet<LayoutConstraintInfo> LayoutConstraints;
@@ -632,7 +633,6 @@ struct ASTContext::Implementation {
   llvm::DenseMap<BuiltinIntegerWidth, BuiltinIntegerType*> BuiltinIntegerTypes;
   llvm::DenseMap<unsigned, BuiltinUnboundGenericType*> BuiltinUnboundGenericTypes;
   llvm::FoldingSet<BuiltinVectorType> BuiltinVectorTypes;
-  llvm::FoldingSet<BuiltinFixedArrayType> BuiltinFixedArrayTypes;
   llvm::FoldingSet<DeclName::CompoundDeclName> CompoundNames;
   llvm::DenseMap<UUID, GenericEnvironment *> OpenedElementEnvironments;
   llvm::FoldingSet<IndexSubset> IndexSubsets;
@@ -808,15 +808,15 @@ ASTContext::ASTContext(
       StdlibModuleName(getIdentifier(STDLIB_NAME)),
       SwiftShimsModuleName(getIdentifier(SWIFT_SHIMS_NAME)),
       blockListConfig(SourceMgr),
-      TheErrorType(new(*this, AllocationArena::Permanent) ErrorType(
-          *this, Type(), RecursiveTypeProperties::HasError)),
-      TheUnresolvedType(new(*this, AllocationArena::Permanent)
-                            UnresolvedType(*this)),
+      TheErrorType(new (*this, AllocationArena::Permanent)
+                       ErrorType(*this, Type())),
       TheEmptyTupleType(TupleType::get(ArrayRef<TupleTypeElt>(), *this)),
       TheEmptyPackType(PackType::get(*this, {})),
       TheAnyType(ProtocolCompositionType::theAnyType(*this)),
       TheUnconstrainedAnyType(
           ProtocolCompositionType::theUnconstrainedAnyType(*this)),
+      TheSelfType(CanGenericTypeParamType(
+          GenericTypeParamType::getType(0, 0, *this))),
 #define SINGLETON_TYPE(SHORT_ID, ID) \
     The##SHORT_ID##Type(new (*this, AllocationArena::Permanent) \
                           ID##Type(*this)),
@@ -838,6 +838,12 @@ ASTContext::ASTContext(
 #define IDENTIFIER_WITH_NAME(Name, IdStr) Id_##Name = getIdentifier(IdStr);
 #include "swift/AST/KnownIdentifiers.def"
 
+  Identifier stdlibOverlayNames[] = {
+    Id_Concurrency,
+    Id_StringProcessing
+  };
+  StdlibOverlayNames = AllocateCopy(stdlibOverlayNames);
+
   // Record the initial set of search paths.
   for (const auto &path : SearchPathOpts.getImportSearchPaths())
     getImpl().SearchPathsSet[path.Path] |= SearchPathKind::Import;
@@ -1678,7 +1684,7 @@ ASTContext::getBuiltinInitDecl(NominalTypeDecl *decl,
   }
 
   auto *ctx = const_cast<ASTContext *>(this);
-  witness = builtinConformance.getWitnessByName(type, initName(*ctx));
+  witness = builtinConformance.getWitnessByName(initName(*ctx));
   if (!witness) {
     assert(false && "Missing required witness");
     witness = ConcreteDeclRef();
@@ -2151,15 +2157,14 @@ void ASTContext::addModuleInterfaceChecker(
   getImpl().InterfaceChecker = std::move(checker);
 }
 
-void ASTContext::setModuleAliases(const llvm::StringMap<StringRef> &aliasMap) {
+void ASTContext::setModuleAliases(
+    const llvm::StringMap<std::string> &aliasMap) {
   // This setter should be called only once after ASTContext has been initialized
   assert(ModuleAliasMap.empty());
-  
-  for (auto k: aliasMap.keys()) {
-    auto v = aliasMap.lookup(k);
-    if (!v.empty()) {
-      addModuleAlias(k, v);
-    }
+
+  for (auto &entry : aliasMap) {
+    if (!entry.getValue().empty())
+      addModuleAlias(entry.getKey(), entry.getValue());
   }
 }
 
@@ -2199,59 +2204,6 @@ Identifier ASTContext::getRealModuleName(Identifier key, ModuleAliasLookupOption
   return value.first;
 }
 
-namespace {
-  static StringRef pathStringFromSearchPath(
-      const SearchPathOptions::SearchPath &next) {
-    return next.Path;
-  }
-}
-
-std::vector<std::string> ASTContext::getDarwinImplicitFrameworkSearchPaths()
-const {
-  assert(LangOpts.Target.isOSDarwin());
-  return SearchPathOpts.getDarwinImplicitFrameworkSearchPaths();
-}
-
-llvm::StringSet<> ASTContext::getAllModuleSearchPathsSet()
-const {
-  llvm::StringSet<> result;
-
-  // Import and framework paths are "special", they contain more than path
-  // strings, but path strings are all we care about here.
-  using SearchPathView = ArrayRefView<SearchPathOptions::SearchPath, StringRef,
-                                      pathStringFromSearchPath>;
-
-  SearchPathView importPathsOnly{SearchPathOpts.getImportSearchPaths()};
-  result.insert(importPathsOnly.begin(), importPathsOnly.end());
-
-  SearchPathView frameworkPathsOnly{SearchPathOpts.getFrameworkSearchPaths()};
-  result.insert(frameworkPathsOnly.begin(), frameworkPathsOnly.end());
-
-  if (LangOpts.Target.isOSDarwin()) {
-    auto implicitFrameworkSearchPaths = getDarwinImplicitFrameworkSearchPaths();
-    result.insert(implicitFrameworkSearchPaths.begin(),
-                  implicitFrameworkSearchPaths.end());
-  }
-  result.insert(SearchPathOpts.RuntimeLibraryImportPaths.begin(),
-                SearchPathOpts.RuntimeLibraryImportPaths.end());
-
-  // ClangImporter special-cases the path for SwiftShims, so do the same here
-  // If there are no shims in the resource dir, add a search path in the SDK.
-  SmallString<128> shimsPath(SearchPathOpts.RuntimeResourcePath);
-  llvm::sys::path::append(shimsPath, "shims");
-  if (!llvm::sys::fs::exists(shimsPath)) {
-    shimsPath = SearchPathOpts.getSDKPath();
-    llvm::sys::path::append(shimsPath, "usr", "lib", "swift", "shims");
-  }
-  result.insert(shimsPath.str());
-
-  // Clang system modules are found in the SDK root
-  SmallString<128> clangSysRootPath(SearchPathOpts.getSDKPath());
-  llvm::sys::path::append(clangSysRootPath, "usr", "include");
-  result.insert(clangSysRootPath.str());
-  return result;
-}
-
 void ASTContext::loadExtensions(NominalTypeDecl *nominal,
                                 unsigned previousGeneration) {
   PrettyStackTraceDecl stackTrace("loading extensions for", nominal);
@@ -2338,8 +2290,8 @@ unsigned ASTContext::getNextMacroDiscriminator(
     MacroDiscriminatorContext context,
     DeclBaseName baseName
 ) {
-  std::pair<const void *, Identifier> key(
-      context.getOpaqueValue(), baseName.getIdentifier());
+  std::pair<const void *, DeclBaseName> key(
+      context.getOpaqueValue(), baseName);
   return getImpl().NextMacroDiscriminator[key]++;
 }
 
@@ -2432,16 +2384,35 @@ void ASTContext::addLoadedModule(ModuleDecl *M) {
   // For example, if '-module-alias Foo=Bar' is passed in to the frontend,
   // and a source file has 'import Foo', a module called Bar (real name)
   // will be loaded and added to the map.
-  getImpl().LoadedModules[M->getRealName()] = M;
+
+  auto RealName = M->getRealName();
+  auto ABIName = M->getABIName();
+
+  auto &LoadedModules = getImpl().LoadedModules;
+  auto &NameToModules = getImpl().NameToModules;
+
+  // If a module with the same name has been loaded before, remove it from the
+  // list of modules that share the same name.
+  if (auto *current = LoadedModules.lookup(RealName)) {
+    auto isCurrentModule = [&](ModuleDecl *module) {
+      return module == current;
+    };
+    llvm::erase_if(NameToModules[RealName], isCurrentModule);
+
+    if (RealName != ABIName)
+      llvm::erase_if(NameToModules[ABIName], isCurrentModule);
+  }
+
+  LoadedModules[RealName] = M;
 
   // Add the module to the mapping from module name to list of modules that
   // share that name.
-  getImpl().NameToModules[M->getRealName()].push_back(M);
+  NameToModules[RealName].push_back(M);
 
   // If the ABI name differs from the real name, also add the module to the list
   // that share that ABI name.
-  if (M->getRealName() != M->getABIName())
-    getImpl().NameToModules[M->getABIName()].push_back(M);
+  if (RealName != ABIName)
+    NameToModules[ABIName].push_back(M);
 }
 
 void ASTContext::removeLoadedModule(Identifier RealName) {
@@ -2551,8 +2522,7 @@ void OverriddenDeclsRequest::cacheResult(
 
   // Record the overrides in the context.
   auto &ctx = decl->getASTContext();
-  auto overriddenCopy =
-    ctx.AllocateCopy(value.operator ArrayRef<ValueDecl *>());
+  auto overriddenCopy = ctx.AllocateCopy(ArrayRef<ValueDecl *>(value));
   (void)ctx.getImpl().Overrides.insert({decl, overriddenCopy});
 }
 
@@ -2669,7 +2639,7 @@ void ASTContext::addSucceededCanImportModule(
 
 bool ASTContext::canImportModuleImpl(
     ImportPath::Module ModuleName, SourceLoc loc, llvm::VersionTuple version,
-    bool underlyingVersion, bool isSourceCanImport,
+    bool isUnderlyingVersion, bool isSourceCanImport,
     llvm::VersionTuple &foundVersion,
     llvm::VersionTuple &foundUnderlyingClangVersion) const {
   SmallString<64> FullModuleName;
@@ -2681,16 +2651,16 @@ bool ASTContext::canImportModuleImpl(
     return false;
 
   auto missingVersion = [this, &loc, &ModuleName,
-                                 &underlyingVersion]() -> bool {
+                         &isUnderlyingVersion]() -> bool {
     // The module version could not be parsed from the preferred source for
-    // this query. Diagnose and return `true` to indicate that the unversioned module
-    // will satisfy the query.
+    // this query. Diagnose and return `true` to indicate that the unversioned
+    // module will satisfy the query.
     auto mID = ModuleName[0];
     auto diagLoc = mID.Loc;
     if (mID.Loc.isInvalid())
       diagLoc = loc;
-    Diags.diagnose(diagLoc, diag::cannot_find_project_version, mID.Item.str(),
-                   underlyingVersion);
+    Diags.diagnose(diagLoc, diag::cannot_find_module_version, mID.Item.str(),
+                   isUnderlyingVersion);
     return true;
   };
 
@@ -2702,9 +2672,9 @@ bool ASTContext::canImportModuleImpl(
     if (version.empty())
       return true;
 
-    const auto &foundComparisonVersion = underlyingVersion
-                                      ? Found->second.UnderlyingVersion
-                                      : Found->second.Version;
+    const auto &foundComparisonVersion = isUnderlyingVersion
+                                             ? Found->second.UnderlyingVersion
+                                             : Found->second.Version;
     if (!foundComparisonVersion.empty())
       return version <= foundComparisonVersion;
     else
@@ -2751,10 +2721,10 @@ bool ASTContext::canImportModuleImpl(
         bestUnderlyingVersionInfo = versionInfo;
     }
 
-    if (!underlyingVersion && !bestVersionInfo.isValid())
+    if (!isUnderlyingVersion && !bestVersionInfo.isValid())
       return false;
 
-    if (underlyingVersion && !bestUnderlyingVersionInfo.isValid())
+    if (isUnderlyingVersion && !bestUnderlyingVersionInfo.isValid())
       return false;
 
     foundVersion = bestVersionInfo.getVersion();
@@ -2803,7 +2773,8 @@ bool ASTContext::canImportModuleImpl(
   if (!lookupVersionedModule(versionInfo, underlyingVersionInfo))
     return false;
 
-  const auto &queryVersion = underlyingVersion ? underlyingVersionInfo : versionInfo;
+  const auto &queryVersion =
+      isUnderlyingVersion ? underlyingVersionInfo : versionInfo;
   if (queryVersion.getVersion().empty())
     return missingVersion();
 
@@ -2965,10 +2936,10 @@ NormalProtocolConformance *
 ASTContext::getNormalConformance(Type conformingType,
                                  ProtocolDecl *protocol,
                                  SourceLoc loc,
+                                 TypeRepr *inheritedTypeRepr,
                                  DeclContext *dc,
                                  ProtocolConformanceState state,
-                                 ProtocolConformanceOptions options,
-                                 SourceLoc preconcurrencyLoc) {
+                                 ProtocolConformanceOptions options) {
   assert(dc->isTypeContext());
 
   llvm::FoldingSetNodeID id;
@@ -2982,8 +2953,7 @@ ASTContext::getNormalConformance(Type conformingType,
 
   // Build a new normal protocol conformance.
   auto result = new (*this) NormalProtocolConformance(
-      conformingType, protocol, loc, dc, state,
-      options, preconcurrencyLoc);
+      conformingType, protocol, loc, inheritedTypeRepr, dc, state, options);
   normalConformances.InsertNode(result, insertPos);
 
   return result;
@@ -3506,7 +3476,7 @@ TypeAliasType::TypeAliasType(TypeAliasDecl *typealias, Type parent,
   // Record the parent (or absence of a parent).
   if (parent) {
     Bits.TypeAliasType.HasParent = true;
-    *getTrailingObjects<Type>() = parent;
+    *getTrailingObjects() = parent;
   } else {
     Bits.TypeAliasType.HasParent = false;
   }
@@ -3519,8 +3489,7 @@ TypeAliasType::TypeAliasType(TypeAliasDecl *typealias, Type parent,
     ASSERT(params->size() == count);
     Bits.TypeAliasType.GenericArgCount = count;
     std::uninitialized_copy(genericArgs.begin(), genericArgs.end(),
-                            getTrailingObjects<Type>() +
-                            (parent ? 1 : 0));
+                            getTrailingObjects() + (parent ? 1 : 0));
   } else {
     ASSERT(params == nullptr);
     Bits.TypeAliasType.GenericArgCount = 0;
@@ -3543,6 +3512,12 @@ TypeAliasType *TypeAliasType::get(TypeAliasDecl *typealias, Type parent,
   auto &ctx = underlying->getASTContext();
   auto arena = getArena(properties);
 
+  // Typealiases can't meaningfully be unsafe; it's the underlying type that
+  // matters.
+  properties.removeIsUnsafe();
+  if (underlying->isUnsafe())
+    properties |= RecursiveTypeProperties::IsUnsafe;
+
   // Profile the type.
   llvm::FoldingSetNodeID id;
   TypeAliasType::Profile(id, typealias, parent, genericArgs, underlying);
@@ -3622,8 +3597,36 @@ void LocatableType::Profile(llvm::FoldingSetNodeID &id, SourceLoc loc,
 // Simple accessors.
 Type ErrorType::get(const ASTContext &C) { return C.TheErrorType; }
 
+static Type replacingTypeVariablesAndPlaceholders(Type ty) {
+  if (!ty || !ty->hasTypeVariableOrPlaceholder())
+    return ty;
+
+  auto &ctx = ty->getASTContext();
+
+  return ty.transformRec([&](Type ty) -> std::optional<Type> {
+    if (!ty->hasTypeVariableOrPlaceholder())
+      return ty;
+
+    auto *typePtr = ty.getPointer();
+    if (isa<TypeVariableType>(typePtr) || isa<PlaceholderType>(typePtr))
+      return ErrorType::get(ctx);
+
+    return std::nullopt;
+  });
+}
+
 Type ErrorType::get(Type originalType) {
-  assert(originalType);
+  // The original type is only used for printing/debugging, and we don't support
+  // solver-allocated ErrorTypes. As such, fold any type variables and
+  // placeholders into ErrorTypes. If we have a top-level one, we can return
+  // that directly.
+  originalType = replacingTypeVariablesAndPlaceholders(originalType);
+  if (isa<ErrorType>(originalType.getPointer()))
+    return originalType;
+
+  ASSERT(originalType);
+  ASSERT(!originalType->getRecursiveProperties().isSolverAllocated() &&
+         "Solver-allocated error types not supported");
 
   auto originalProperties = originalType->getRecursiveProperties();
   auto arena = getArena(originalProperties);
@@ -3634,14 +3637,7 @@ Type ErrorType::get(Type originalType) {
 
   void *mem = ctx.Allocate(sizeof(ErrorType) + sizeof(Type),
                            alignof(ErrorType), arena);
-  RecursiveTypeProperties properties = RecursiveTypeProperties::HasError;
-
-  // We need to preserve the solver allocated bit, to ensure any wrapping
-  // types are solver allocated too.
-  if (originalProperties.isSolverAllocated())
-    properties |= RecursiveTypeProperties::SolverAllocated;
-
-  return entry = new (mem) ErrorType(ctx, originalType, properties);
+  return entry = new (mem) ErrorType(ctx, originalType);
 }
 
 void ErrorUnionType::Profile(llvm::FoldingSetNodeID &id, ArrayRef<Type> terms) {
@@ -3698,6 +3694,9 @@ Type PlaceholderType::get(ASTContext &ctx, Originator originator) {
     if (auto *depTy = originator.dyn_cast<DependentMemberType *>())
       return depTy->getRecursiveProperties();
 
+    if (auto *errTy = originator.dyn_cast<ErrorType *>())
+      return errTy->getRecursiveProperties();
+
     return RecursiveTypeProperties();
   }();
   auto arena = getArena(originatorProps);
@@ -3724,8 +3723,9 @@ IntegerType *IntegerType::get(StringRef value, bool isNegative,
   IntegerType::Profile(id, value, isNegative);
 
   void *insertPos;
-  if (auto intType = ctx.getImpl().IntegerTypes.FindNodeOrInsertPos(id, insertPos))
+  if (auto intType = ctx.getImpl().IntegerTypes.FindNodeOrInsertPos(id, insertPos)) {
     return intType;
+  }
 
   auto strCopy = ctx.AllocateCopy(value);
 
@@ -3760,20 +3760,26 @@ BuiltinUnboundGenericType::get(TypeKind genericTypeKind,
 
 BuiltinFixedArrayType *BuiltinFixedArrayType::get(CanType Size,
                                                   CanType ElementType) {
+  RecursiveTypeProperties properties;
+  properties |= Size->getRecursiveProperties();
+  properties |= ElementType->getRecursiveProperties();
+
+  AllocationArena arena = getArena(properties);
+
   llvm::FoldingSetNodeID id;
   BuiltinFixedArrayType::Profile(id, Size, ElementType);
-  auto &context = Size->getASTContext();
+  auto &ctx = Size->getASTContext();
 
   void *insertPos;
-  if (BuiltinFixedArrayType *vecType
-        = context.getImpl().BuiltinFixedArrayTypes
+  if (BuiltinFixedArrayType *faTy
+        = ctx.getImpl().getArena(arena).BuiltinFixedArrayTypes
                  .FindNodeOrInsertPos(id, insertPos))
-    return vecType;
+    return faTy;
 
   BuiltinFixedArrayType *faTy
-    = new (context, AllocationArena::Permanent)
-        BuiltinFixedArrayType(Size, ElementType);
-  context.getImpl().BuiltinFixedArrayTypes.InsertNode(faTy, insertPos);
+    = new (ctx, arena) BuiltinFixedArrayType(Size, ElementType, properties);
+  ctx.getImpl().getArena(arena).BuiltinFixedArrayTypes
+      .InsertNode(faTy, insertPos);
   return faTy;
 }
 
@@ -3924,7 +3930,7 @@ PackElementType::PackElementType(Type packType, unsigned level,
     packType(packType), level(level) {
   assert(packType->isParameterPack() ||
          packType->is<PackArchetypeType>() ||
-         packType->is<TypeVariableType>());
+         packType->isTypeVariableOrMember());
   assert(level > 0);
 }
 
@@ -4092,7 +4098,7 @@ AnyFunctionType::Param swift::computeSelfParam(AbstractFunctionDecl *AFD,
     // Methods returning 'Self' have a dynamic 'self'.
     //
     // FIXME: All methods of non-final classes should have this.
-    else if (wantDynamicSelf && FD->hasDynamicSelfResult())
+    else if (wantDynamicSelf && FD->getResultInterfaceType()->hasDynamicSelfType())
       isDynamicSelf = true;
 
   } else if (auto *CD = dyn_cast<ConstructorDecl>(AFD)) {
@@ -4189,6 +4195,54 @@ void UnboundGenericType::Profile(llvm::FoldingSetNodeID &ID,
   ID.AddPointer(Parent.getPointer());
 }
 
+/// The safety of a parent type does not have an impact on a nested type within
+/// it. This produces the recursive properties of a given type that should
+/// be propagated to a nested type, which won't include any "IsUnsafe" bit
+/// determined based on the declaration itself.
+static RecursiveTypeProperties getRecursivePropertiesAsParent(Type type) {
+  if (!type)
+    return RecursiveTypeProperties();
+
+  // We only need to do anything interesting at all for unsafe types.
+  auto properties = type->getRecursiveProperties();
+  if (!properties.isUnsafe())
+    return properties;
+
+  if (auto nominal = type->getAnyNominal()) {
+    // If the nominal wasn't itself unsafe, then we got the unsafety from
+    // something else (e.g., a generic argument), so it won't change.
+    if (nominal->getExplicitSafety() != ExplicitSafety::Unsafe)
+      return properties;
+  }
+
+  // Drop the "unsafe" bit. We have to recompute it without considering the
+  // enclosing nominal type.
+  properties.removeIsUnsafe();
+
+  // Check generic arguments of parent types.
+  while (type) {
+    // Merge from the generic arguments.
+    if (auto boundGeneric = type->getAs<BoundGenericType>()) {
+      for (auto genericArg : boundGeneric->getGenericArgs())
+        properties |= genericArg->getRecursiveProperties();
+    }
+
+    if (auto nominalOrBound = type->getAs<NominalOrBoundGenericNominalType>()) {
+      type = nominalOrBound->getParent();
+      continue;
+    }
+
+    if (auto unbound = type->getAs<UnboundGenericType>()) {
+      type = unbound->getParent();
+      continue;
+    }
+
+    break;
+  };
+
+  return properties;
+}
+
 UnboundGenericType *UnboundGenericType::
 get(GenericTypeDecl *TheDecl, Type Parent, const ASTContext &C) {
   llvm::FoldingSetNodeID ID;
@@ -4197,7 +4251,7 @@ get(GenericTypeDecl *TheDecl, Type Parent, const ASTContext &C) {
   RecursiveTypeProperties properties;
   if (TheDecl->getExplicitSafety() == ExplicitSafety::Unsafe)
     properties |= RecursiveTypeProperties::IsUnsafe;
-  if (Parent) properties |= Parent->getRecursiveProperties();
+  properties |= getRecursivePropertiesAsParent(Parent);
 
   auto arena = getArena(properties);
 
@@ -4251,7 +4305,7 @@ BoundGenericType *BoundGenericType::get(NominalTypeDecl *TheDecl,
   RecursiveTypeProperties properties;
   if (TheDecl->getExplicitSafety() == ExplicitSafety::Unsafe)
     properties |= RecursiveTypeProperties::IsUnsafe;
-  if (Parent) properties |= Parent->getRecursiveProperties();
+  properties |= getRecursivePropertiesAsParent(Parent);
   for (Type Arg : GenericArgs) {
     properties |= Arg->getRecursiveProperties();
   }
@@ -4334,7 +4388,7 @@ EnumType *EnumType::get(EnumDecl *D, Type Parent, const ASTContext &C) {
   RecursiveTypeProperties properties;
   if (D->getExplicitSafety() == ExplicitSafety::Unsafe)
     properties |= RecursiveTypeProperties::IsUnsafe;
-  if (Parent) properties |= Parent->getRecursiveProperties();
+  properties |= getRecursivePropertiesAsParent(Parent);
   auto arena = getArena(properties);
 
   auto *&known = C.getImpl().getArena(arena).EnumTypes[{D, Parent}];
@@ -4352,7 +4406,7 @@ StructType *StructType::get(StructDecl *D, Type Parent, const ASTContext &C) {
   RecursiveTypeProperties properties;
   if (D->getExplicitSafety() == ExplicitSafety::Unsafe)
     properties |= RecursiveTypeProperties::IsUnsafe;
-  if (Parent) properties |= Parent->getRecursiveProperties();
+  properties |= getRecursivePropertiesAsParent(Parent);
   auto arena = getArena(properties);
 
   auto *&known = C.getImpl().getArena(arena).StructTypes[{D, Parent}];
@@ -4370,7 +4424,7 @@ ClassType *ClassType::get(ClassDecl *D, Type Parent, const ASTContext &C) {
   RecursiveTypeProperties properties;
   if (D->getExplicitSafety() == ExplicitSafety::Unsafe)
     properties |= RecursiveTypeProperties::IsUnsafe;
-  if (Parent) properties |= Parent->getRecursiveProperties();
+  properties |= getRecursivePropertiesAsParent(Parent);
   auto arena = getArena(properties);
 
   auto *&known = C.getImpl().getArena(arena).ClassTypes[{D, Parent}];
@@ -4632,6 +4686,8 @@ isAnyFunctionTypeCanonical(ArrayRef<AnyFunctionType::Param> params,
 // For now, generic function types cannot be dependent (in fact,
 // they erase dependence) or contain type variables, and they're
 // always materializable.
+// FIXME: This doesn't seem great, we should consider changing it to be opt-out
+// rather than opt-in.
 static RecursiveTypeProperties
 getGenericFunctionRecursiveProperties(ArrayRef<AnyFunctionType::Param> params,
                                       Type result, Type globalActor,
@@ -4640,34 +4696,25 @@ getGenericFunctionRecursiveProperties(ArrayRef<AnyFunctionType::Param> params,
                 "revisit this if you add new recursive type properties");
   RecursiveTypeProperties properties;
 
-  for (auto param : params) {
-    if (param.getPlainType()->getRecursiveProperties().hasError())
-      properties |= RecursiveTypeProperties::HasError;
-    if (param.getPlainType()->getRecursiveProperties().isUnsafe())
-      properties |= RecursiveTypeProperties::IsUnsafe;
-  }
+  using Prop = RecursiveTypeProperties::Property;
+  auto mask = (unsigned)Prop::HasError | Prop::IsUnsafe | Prop::HasPlaceholder;
+
+  auto unionBits = [&](Type ty) {
+    if (!ty)
+      return;
+    auto bits = ty->getRecursiveProperties().getBits();
+    properties |= Prop(bits & mask);
+  };
+
+  for (auto param : params)
+    unionBits(param.getPlainType());
 
   if (result->getRecursiveProperties().hasDynamicSelf())
     properties |= RecursiveTypeProperties::HasDynamicSelf;
-  if (result->getRecursiveProperties().hasError())
-    properties |= RecursiveTypeProperties::HasError;
-  if (result->getRecursiveProperties().isUnsafe())
-    properties |= RecursiveTypeProperties::IsUnsafe;
-  
-  if (globalActor) {
-    if (globalActor->getRecursiveProperties().hasError())
-      properties |= RecursiveTypeProperties::HasError;
-    if (globalActor->getRecursiveProperties().isUnsafe())
-      properties |= RecursiveTypeProperties::IsUnsafe;
-  }
-
-  if (thrownError) {
-    if (thrownError->getRecursiveProperties().hasError())
-      properties |= RecursiveTypeProperties::HasError;
-    if (thrownError->getRecursiveProperties().isUnsafe())
-      properties |= RecursiveTypeProperties::IsUnsafe;
-  }
 
+  unionBits(result);
+  unionBits(globalActor);
+  unionBits(thrownError);
   return properties;
 }
 
@@ -5044,8 +5091,8 @@ GenericTypeParamType *GenericTypeParamType::get(Identifier name,
                                                 Type valueType,
                                                 const ASTContext &ctx) {
   llvm::FoldingSetNodeID id;
-  GenericTypeParamType::Profile(id, paramKind, depth, index, valueType,
-                                name);
+  GenericTypeParamType::Profile(id, paramKind, depth, index, /*weight=*/0,
+                                valueType, name);
 
   void *insertPos;
   if (auto gpTy = ctx.getImpl().GenericParamTypes.FindNodeOrInsertPos(id, insertPos))
@@ -5055,8 +5102,8 @@ GenericTypeParamType *GenericTypeParamType::get(Identifier name,
   if (paramKind == GenericTypeParamKind::Pack)
     props |= RecursiveTypeProperties::HasParameterPack;
 
-  auto canType = GenericTypeParamType::get(paramKind, depth, index, valueType,
-                                           ctx);
+  auto canType = GenericTypeParamType::get(paramKind, depth, index, /*weight=*/0,
+                                           valueType, ctx);
 
   auto result = new (ctx, AllocationArena::Permanent)
       GenericTypeParamType(name, canType, ctx);
@@ -5075,10 +5122,10 @@ GenericTypeParamType *GenericTypeParamType::get(GenericTypeParamDecl *param) {
 
 GenericTypeParamType *GenericTypeParamType::get(GenericTypeParamKind paramKind,
                                                 unsigned depth, unsigned index,
-                                                Type valueType,
+                                                unsigned weight, Type valueType,
                                                 const ASTContext &ctx) {
   llvm::FoldingSetNodeID id;
-  GenericTypeParamType::Profile(id, paramKind, depth, index, valueType,
+  GenericTypeParamType::Profile(id, paramKind, depth, index, weight, valueType,
                                 Identifier());
 
   void *insertPos;
@@ -5090,7 +5137,7 @@ GenericTypeParamType *GenericTypeParamType::get(GenericTypeParamKind paramKind,
     props |= RecursiveTypeProperties::HasParameterPack;
 
   auto result = new (ctx, AllocationArena::Permanent)
-      GenericTypeParamType(paramKind, depth, index, valueType, props, ctx);
+      GenericTypeParamType(paramKind, depth, index, weight, valueType, props, ctx);
   ctx.getImpl().GenericParamTypes.InsertNode(result, insertPos);
   return result;
 }
@@ -5099,14 +5146,21 @@ GenericTypeParamType *GenericTypeParamType::getType(unsigned depth,
                                                     unsigned index,
                                                     const ASTContext &ctx) {
   return GenericTypeParamType::get(GenericTypeParamKind::Type, depth, index,
-                                   /*valueType*/ Type(), ctx);
+                                   /*weight=*/0, /*valueType=*/Type(), ctx);
+}
+
+GenericTypeParamType *GenericTypeParamType::getOpaqueResultType(unsigned depth,
+                                                                unsigned index,
+                                                                const ASTContext &ctx) {
+  return GenericTypeParamType::get(GenericTypeParamKind::Type, depth, index,
+                                   /*weight=*/1, /*valueType=*/Type(), ctx);
 }
 
 GenericTypeParamType *GenericTypeParamType::getPack(unsigned depth,
                                                     unsigned index,
                                                     const ASTContext &ctx) {
   return GenericTypeParamType::get(GenericTypeParamKind::Pack, depth, index,
-                                   /*valueType*/ Type(), ctx);
+                                   /*weight=*/0, /*valueType=*/Type(), ctx);
 }
 
 GenericTypeParamType *GenericTypeParamType::getValue(unsigned depth,
@@ -5114,7 +5168,7 @@ GenericTypeParamType *GenericTypeParamType::getValue(unsigned depth,
                                                      Type valueType,
                                                      const ASTContext &ctx) {
   return GenericTypeParamType::get(GenericTypeParamKind::Value, depth, index,
-                                   valueType, ctx);
+                                   /*weight=*/0, valueType, ctx);
 }
 
 ArrayRef<GenericTypeParamType *>
@@ -5312,8 +5366,13 @@ SILFunctionType::SILFunctionType(
              "Cannot return an @noescape function type");
     }
   }
+  bool hasIsolatedParameter = false; (void) hasIsolatedParameter;
   for (auto param : getParameters()) {
-    (void)param;
+    if (param.hasOption(SILParameterInfo::Isolated)) {
+      assert(!hasIsolatedParameter &&
+             "building SIL function type with multiple isolated parameters");
+      hasIsolatedParameter = true;
+    }
     assert(!isa<PackExpansionType>(param.getInterfaceType()) &&
            "Cannot have a pack expansion directly as a parameter");
     assert(param.isPack() == isa<SILPackType>(param.getInterfaceType()) &&
@@ -5537,7 +5596,7 @@ ProtocolType *ProtocolType::get(ProtocolDecl *D, Type Parent,
   RecursiveTypeProperties properties;
   if (D->getExplicitSafety() == ExplicitSafety::Unsafe)
     properties |= RecursiveTypeProperties::IsUnsafe;
-  if (Parent) properties |= Parent->getRecursiveProperties();
+  properties |= getRecursivePropertiesAsParent(Parent);
   auto arena = getArena(properties);
 
   auto *&known = C.getImpl().getArena(arena).ProtocolTypes[{D, Parent}];
@@ -5668,7 +5727,8 @@ OpaqueTypeArchetypeType *OpaqueTypeArchetypeType::getNew(
   ASTContext &ctx = interfaceType->getASTContext();
   auto mem = ctx.Allocate(size, alignof(OpaqueTypeArchetypeType), arena);
   return ::new (mem)
-      OpaqueTypeArchetypeType(environment, properties, interfaceType,
+      OpaqueTypeArchetypeType(environment->isCanonical() ? &ctx : nullptr,
+                              environment, properties, interfaceType,
                               conformsTo, superclass, layout);
 }
 
@@ -5696,6 +5756,7 @@ CanTypeWrapper<ExistentialArchetypeType> ExistentialArchetypeType::getNew(
   void *mem = ctx.Allocate(size, alignof(ExistentialArchetypeType), arena);
 
   return CanExistentialArchetypeType(::new (mem) ExistentialArchetypeType(
+      environment->isCanonical() ? &ctx : nullptr,
       environment, interfaceType, conformsTo, superclass, layout,
       properties));
 }
@@ -5799,7 +5860,7 @@ ProtocolConformanceRef ProtocolConformanceRef::forAbstract(
   case TypeKind::GenericTypeParam:
   case TypeKind::TypeVariable:
   case TypeKind::DependentMember:
-  case TypeKind::Unresolved:
+  case TypeKind::Error:
   case TypeKind::Placeholder:
   case TypeKind::PrimaryArchetype:
   case TypeKind::PackArchetype:
@@ -5809,9 +5870,10 @@ ProtocolConformanceRef ProtocolConformanceRef::forAbstract(
     break;
 
   default:
-    llvm::errs() << "Abstract conformance with bad subject type:\n";
-    conformingType->dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Abstract conformance with bad subject type:\n";
+      conformingType->dump(out);
+    });
   }
 
   // Figure out which arena this should go in.
@@ -5856,20 +5918,20 @@ const AvailabilityContext::Storage *AvailabilityContext::Storage::get(
       ctx.Allocate(storageToAlloc, alignof(AvailabilityContext::Storage));
   auto *newNode = ::new (mem) AvailabilityContext::Storage(
       platformRange, isDeprecated, domainInfos.size());
-  std::uninitialized_copy(
-      domainInfos.begin(), domainInfos.end(),
-      newNode->getTrailingObjects<AvailabilityContext::DomainInfo>());
+  std::uninitialized_copy(domainInfos.begin(), domainInfos.end(),
+                          newNode->getTrailingObjects());
   foldingSet.InsertNode(newNode, insertPos);
 
   return newNode;
 }
 
 const CustomAvailabilityDomain *
-CustomAvailabilityDomain::get(StringRef name, ModuleDecl *mod, Kind kind,
+CustomAvailabilityDomain::get(StringRef name, Kind kind, ModuleDecl *mod,
+                              ValueDecl *decl, FuncDecl *predicateFunc,
                               const ASTContext &ctx) {
   auto identifier = ctx.getIdentifier(name);
   llvm::FoldingSetNodeID id;
-  CustomAvailabilityDomain::Profile(id, identifier, mod, kind);
+  CustomAvailabilityDomain::Profile(id, identifier, mod);
 
   auto &foldingSet = ctx.getImpl().CustomAvailabilityDomains;
   void *insertPos;
@@ -5879,7 +5941,8 @@ CustomAvailabilityDomain::get(StringRef name, ModuleDecl *mod, Kind kind,
 
   void *mem = ctx.Allocate(sizeof(CustomAvailabilityDomain),
                            alignof(CustomAvailabilityDomain));
-  auto *newNode = ::new (mem) CustomAvailabilityDomain(identifier, mod, kind);
+  auto *newNode = ::new (mem)
+      CustomAvailabilityDomain(identifier, kind, mod, decl, predicateFunc);
   foldingSet.InsertNode(newNode, insertPos);
 
   return newNode;
@@ -5942,6 +6005,25 @@ GenericSignature::get(ArrayRef<GenericTypeParamType *> params,
   return newSig;
 }
 
+GenericSignature
+GenericSignature::forInvalid(ArrayRef<GenericTypeParamType *> params) {
+  ASSERT(!params.empty());
+  auto &ctx = params.front()->getASTContext();
+
+  // Add same type requirements that make each of the generic parameters
+  // concrete error types. This helps avoid downstream diagnostics and is
+  // handled the same as if the user wrote e.g `<T where T == Undefined>`.
+  SmallVector<Requirement, 2> requirements;
+  for (auto *param : params) {
+    if (param->isValue())
+      continue;
+
+    requirements.emplace_back(RequirementKind::SameType, param,
+                              ErrorType::get(ctx));
+  }
+  return GenericSignature::get(params, requirements);
+}
+
 GenericEnvironment *GenericEnvironment::forPrimary(GenericSignature signature) {
   auto &ctx = signature->getASTContext();
 
@@ -5949,8 +6031,8 @@ GenericEnvironment *GenericEnvironment::forPrimary(GenericSignature signature) {
   unsigned numGenericParams = signature.getGenericParams().size();
   size_t bytes = totalSizeToAlloc<SubstitutionMap,
                                   OpaqueEnvironmentData,
-                                  OpenedExistentialEnvironmentData,
-                                  OpenedElementEnvironmentData, Type>(
+                                  ExistentialEnvironmentData,
+                                  ElementEnvironmentData, Type>(
       0, 0, 0, 0, numGenericParams);
   void *mem = ctx.Allocate(bytes, alignof(GenericEnvironment));
   return new (mem) GenericEnvironment(signature);
@@ -5960,11 +6042,6 @@ GenericEnvironment *GenericEnvironment::forPrimary(GenericSignature signature) {
 /// outer substitutions.
 GenericEnvironment *GenericEnvironment::forOpaqueType(
     OpaqueTypeDecl *opaque, SubstitutionMap subs) {
-  // TODO: We could attempt to preserve type sugar in the substitution map.
-  // Currently archetypes are assumed to be always canonical in many places,
-  // though, so doing so would require fixing those places.
-  subs = subs.getCanonical();
-
   auto &ctx = opaque->getASTContext();
 
   auto properties = ArchetypeType::archetypeProperties(
@@ -5979,9 +6056,9 @@ GenericEnvironment *GenericEnvironment::forOpaqueType(
     auto signature = opaque->getOpaqueInterfaceGenericSignature();
     unsigned numGenericParams = signature.getGenericParams().size();
     size_t bytes = totalSizeToAlloc<SubstitutionMap,
-                                  OpaqueEnvironmentData,
-                                    OpenedExistentialEnvironmentData,
-                                    OpenedElementEnvironmentData, Type>(
+                                    OpaqueEnvironmentData,
+                                    ExistentialEnvironmentData,
+                                    ElementEnvironmentData, Type>(
         1, 1, 0, 0, numGenericParams);
     void *mem = ctx.Allocate(bytes, alignof(GenericEnvironment), arena);
     env = new (mem) GenericEnvironment(signature, opaque, subs);
@@ -6043,8 +6120,8 @@ GenericEnvironment::forOpenedExistential(
   unsigned numGenericParams = signature.getGenericParams().size();
   size_t bytes = totalSizeToAlloc<SubstitutionMap,
                                   OpaqueEnvironmentData,
-                                  OpenedExistentialEnvironmentData,
-                                  OpenedElementEnvironmentData, Type>(
+                                  ExistentialEnvironmentData,
+                                  ElementEnvironmentData, Type>(
       1, 0, 1, 0, numGenericParams);
   void *mem = ctx.Allocate(bytes, alignof(GenericEnvironment));
   auto *genericEnv =
@@ -6081,8 +6158,8 @@ GenericEnvironment::forOpenedElement(GenericSignature signature,
   unsigned numOpenedParams = signature.getInnermostGenericParams().size();
   size_t bytes = totalSizeToAlloc<SubstitutionMap,
                                   OpaqueEnvironmentData,
-                                  OpenedExistentialEnvironmentData,
-                                  OpenedElementEnvironmentData,
+                                  ExistentialEnvironmentData,
+                                  ElementEnvironmentData,
                                   Type>(
       1, 0, 0, 1, numGenericParams + numOpenedParams);
   void *mem = ctx.Allocate(bytes, alignof(GenericEnvironment));
@@ -6486,7 +6563,7 @@ Type ASTContext::getBridgedToObjC(const DeclContext *dc, Type type,
       *bridgedValueType = type;
 
     // Find the Objective-C class type we bridge to.
-    Type witnessTy = conformance.getTypeWitnessByName(type, Id_ObjectiveCType);
+    Type witnessTy = conformance.getTypeWitnessByName(Id_ObjectiveCType);
     // If Objective-C import is broken, witness type would be a dependent member
     // with `<<error type>>` base.
     return (witnessTy && !witnessTy->hasError()) ? witnessTy : Type();
@@ -6520,13 +6597,16 @@ const clang::Type *
 ASTContext::getClangFunctionType(ArrayRef<AnyFunctionType::Param> params,
                                  Type resultTy,
                                  FunctionTypeRepresentation trueRep) {
-  return getClangTypeConverter().getFunctionType(params, resultTy, trueRep);
+  return getClangTypeConverter().getFunctionType</*templateArgument=*/false>(
+      params, resultTy, trueRep);
 }
 
 const clang::Type *ASTContext::getCanonicalClangFunctionType(
     ArrayRef<SILParameterInfo> params, std::optional<SILResultInfo> result,
     SILFunctionType::Representation trueRep) {
-  auto *ty = getClangTypeConverter().getFunctionType(params, result, trueRep);
+  auto *ty =
+      getClangTypeConverter().getFunctionType</*templateArgument=*/false>(
+          params, result, trueRep);
   return ty ? ty->getCanonicalTypeInternal().getTypePtr() : nullptr;
 }
 
@@ -6583,8 +6663,7 @@ CanGenericSignature ASTContext::getSingleGenericParameterSignature() const {
   if (auto theSig = getImpl().SingleGenericParameterSignature)
     return theSig;
 
-  auto param = GenericTypeParamType::getType(/*depth*/ 0, /*index*/ 0, *this);
-  auto sig = GenericSignature::get(param, { });
+  auto sig = GenericSignature::get({TheSelfType}, { });
   auto canonicalSig = CanGenericSignature(sig);
   getImpl().SingleGenericParameterSignature = canonicalSig;
   return canonicalSig;
@@ -6846,15 +6925,8 @@ CanSILBoxType SILBoxType::get(CanType boxedType) {
                                         /*mutable*/ true),
                                /*captures generic env*/ false);
 
-  auto subMap =
-    SubstitutionMap::get(
-      singleGenericParamSignature,
-      [&](SubstitutableType *type) -> Type {
-        if (type->isEqual(genericParam)) return boxedType;
-
-        return nullptr;
-      },
-      MakeAbstractConformanceForGenericType());
+  auto subMap = SubstitutionMap::get(singleGenericParamSignature, boxedType,
+                                     LookUpConformanceInModule());
   return get(boxedType->getASTContext(), layout, subMap);
 }
 
diff --git a/lib/AST/ASTDemangler.cpp b/lib/AST/ASTDemangler.cpp
index 084facdd8e180..65e846435d357 100644
--- a/lib/AST/ASTDemangler.cpp
+++ b/lib/AST/ASTDemangler.cpp
@@ -24,21 +24,52 @@
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/Decl.h"
+#include "swift/AST/DeclNameExtractor.h"
 #include "swift/AST/GenericSignature.h"
 #include "swift/AST/Module.h"
+#include "swift/AST/ModuleNameLookup.h"
 #include "swift/AST/NameLookup.h"
+#include "swift/AST/NameLookupRequests.h"
 #include "swift/AST/SILLayout.h"
 #include "swift/AST/Type.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/AST/Types.h"
+#include "swift/AST/USRGeneration.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Demangling/Demangler.h"
 #include "swift/Demangling/ManglingMacros.h"
+#include "clang/Tooling/Refactor/USRFinder.h"
 #include "llvm/ADT/StringSwitch.h"
 
 using namespace swift;
 
+Decl *swift::Demangle::getDeclForUSR(ASTContext &ctx, StringRef usr,
+                                     GenericSignature genericSig) {
+  if (!usr.starts_with("s:"))
+    return nullptr;
+
+  std::string mangling(usr);
+  mangling.replace(0, 2, MANGLING_PREFIX_STR);
+
+  Demangle::Context Dem;
+  auto node = Dem.demangleSymbolAsNode(mangling);
+
+  ASTBuilder builder(ctx, genericSig);
+
+  auto hasMatchingUSR = [usr](const ValueDecl *VD) {
+    SmallString<128> candidateUSR;
+    llvm::raw_svector_ostream OS(candidateUSR);
+
+    if (ide::printValueDeclSwiftUSR(VD, OS))
+      return false;
+
+    return usr == candidateUSR;
+  };
+
+  return builder.findDecl(node, /*isMatchingValueDecl=*/hasMatchingUSR);
+}
+
 Type swift::Demangle::getTypeForMangling(ASTContext &ctx,
                                          StringRef mangling,
                                          GenericSignature genericSig) {
@@ -75,6 +106,102 @@ TypeDecl *swift::Demangle::getTypeDeclForUSR(ASTContext &ctx,
   return getTypeDeclForMangling(ctx, mangling, genericSig);
 }
 
+using ValueDeclPredicate = llvm::function_ref<bool(const ValueDecl *)>;
+
+static Decl *findTopLevelClangDecl(ClangModuleLoader *importer, DeclName name,
+                                   ValueDeclPredicate predicate) {
+  struct Consumer : VisibleDeclConsumer {
+    ValueDecl *Result = nullptr;
+    ValueDeclPredicate Predicate;
+
+    explicit Consumer(ValueDeclPredicate Predicate) : Predicate(Predicate) {}
+
+    void foundDecl(ValueDecl *decl, DeclVisibilityKind reason,
+                   DynamicLookupInfo dynamicLookupInfo = {}) override {
+      if (Result != nullptr)
+        return;
+
+      if (Predicate(decl))
+        Result = decl;
+    }
+  } consumer(predicate);
+
+  importer->lookupValue(name, consumer);
+
+  return consumer.Result;
+}
+
+Decl *ASTBuilder::findDecl(
+    NodePointer node,
+    llvm::function_ref<bool(const ValueDecl *)> isMatchingValueDecl) {
+  if (node == nullptr)
+    return nullptr;
+
+  if (auto *TD = createTypeDecl(node))
+    return TD;
+
+  switch (node->getKind()) {
+  case Node::Kind::Global:
+  case Node::Kind::Static:
+  case Node::Kind::BoundGenericEnum:
+  case Node::Kind::BoundGenericClass:
+  case Node::Kind::BoundGenericFunction:
+  case Node::Kind::BoundGenericProtocol:
+  case Node::Kind::BoundGenericStructure:
+  case Node::Kind::BoundGenericTypeAlias:
+  case Node::Kind::BoundGenericOtherNominalType:
+    return findDecl(node->getFirstChild(), isMatchingValueDecl);
+  default:
+    // We should have arrived at a declaration node by now
+    break;
+  }
+
+  DeclNameExtractor NameExtractor(Ctx);
+
+  DeclName name;
+  Identifier privateDiscriminator;
+  if (!NameExtractor.extractDeclName(node, name, privateDiscriminator))
+    return nullptr;
+
+  auto contextNode = node->getFirstChild();
+  if (!contextNode)
+    return nullptr;
+
+  SmallVector<ValueDecl *, 4> candidates;
+  if (contextNode->getKind() == Node::Kind::Module) {
+    // If a foreign Clang module, perform lookup in Clang importer
+    if (getForeignModuleKind(contextNode)) {
+      auto *importer = Ctx.getClangModuleLoader();
+      return findTopLevelClangDecl(importer, name, isMatchingValueDecl);
+    }
+
+    ModuleDecl *scratch;
+    auto potentialModules = findPotentialModules(contextNode, scratch);
+
+    for (auto *module : potentialModules) {
+      module->lookupMember(candidates, module, name, privateDiscriminator);
+    }
+  } else {
+    auto *DC = findDeclContext(contextNode);
+    if (!DC)
+      return nullptr;
+
+    auto *module = DC->getParentModule();
+
+    if (isa<ExtensionDecl>(DC))
+      DC = DC->getSelfNominalTypeDecl();
+
+    module->lookupMember(candidates, DC, name, privateDiscriminator);
+  }
+
+  for (auto *candidate : candidates) {
+    if (isMatchingValueDecl(candidate))
+      return candidate;
+  }
+
+  return nullptr;
+}
+
 Type ASTBuilder::decodeMangledType(NodePointer node, bool forRequirement) {
   return swift::Demangle::decodeMangledType(*this, node, forRequirement)
       .getType();
@@ -205,8 +332,7 @@ Type ASTBuilder::createTypeAliasType(GenericTypeDecl *decl, Type parent) {
 
 static SubstitutionMap
 createSubstitutionMapFromGenericArgs(GenericSignature genericSig,
-                                     ArrayRef<Type> args,
-                                     LookupConformanceFn lookupConformance) {
+                                     ArrayRef<Type> args) {
   if (!genericSig)
     return SubstitutionMap();
   
@@ -214,15 +340,7 @@ createSubstitutionMapFromGenericArgs(GenericSignature genericSig,
     return SubstitutionMap();
 
   return SubstitutionMap::get(
-      genericSig,
-      [&](SubstitutableType *t) -> Type {
-        auto *gp = cast<GenericTypeParamType>(t);
-        unsigned ordinal = genericSig->getGenericParamOrdinal(gp);
-        if (ordinal < args.size())
-          return args[ordinal];
-        return Type();
-      },
-      lookupConformance);
+      genericSig, args, LookUpConformanceInModule());
 }
 
 Type ASTBuilder::createBoundGenericType(GenericTypeDecl *decl,
@@ -237,8 +355,7 @@ Type ASTBuilder::createBoundGenericType(GenericTypeDecl *decl,
 
   // Build a SubstitutionMap.
   auto genericSig = nominalDecl->getGenericSignature();
-  auto subs = createSubstitutionMapFromGenericArgs(
-      genericSig, args, LookUpConformanceInModule());
+  auto subs = createSubstitutionMapFromGenericArgs(genericSig, args);
   if (!subs)
     return Type();
   auto origType = nominalDecl->getDeclaredInterfaceType();
@@ -248,46 +365,53 @@ Type ASTBuilder::createBoundGenericType(GenericTypeDecl *decl,
   return origType.subst(subs);
 }
 
+OpaqueTypeDecl *ASTBuilder::resolveOpaqueTypeDecl(NodePointer opaqueDescriptor) {
+  if (opaqueDescriptor->getKind() != Node::Kind::OpaqueReturnTypeOf)
+    return nullptr;
+
+  auto definingDecl = opaqueDescriptor->getChild(0);
+  auto definingGlobal = Factory.createNode(Node::Kind::Global);
+  definingGlobal->addChild(definingDecl, Factory);
+  auto mangling = mangleNode(definingGlobal, ManglingFlavor);
+  if (!mangling.isSuccess())
+    return nullptr;
+  auto mangledName = mangling.result();
+
+  auto moduleNode = findModuleNode(definingDecl);
+  if (!moduleNode)
+    return nullptr;
+
+  ModuleDecl *scratch;
+  auto potentialParentModules = findPotentialModules(moduleNode, scratch);
+  if (potentialParentModules.empty())
+    return nullptr;
+
+  for (auto module : potentialParentModules)
+    if (auto decl = module->lookupOpaqueResultType(mangledName))
+      return decl;
+
+  return nullptr;
+}
+
 Type ASTBuilder::resolveOpaqueType(NodePointer opaqueDescriptor,
                                    ArrayRef<ArrayRef<Type>> args,
                                    unsigned ordinal) {
-  if (opaqueDescriptor->getKind() == Node::Kind::OpaqueReturnTypeOf) {
-    auto definingDecl = opaqueDescriptor->getChild(0);
-    auto definingGlobal = Factory.createNode(Node::Kind::Global);
-    definingGlobal->addChild(definingDecl, Factory);
-    auto mangling = mangleNode(definingGlobal, ManglingFlavor);
-    if (!mangling.isSuccess())
-      return Type();
-    auto mangledName = mangling.result();
-
-    auto moduleNode = findModuleNode(definingDecl);
-    if (!moduleNode)
-      return Type();
-    auto potentialParentModules = findPotentialModules(moduleNode);
-    if (potentialParentModules.empty())
-      return Type();
+  OpaqueTypeDecl *opaqueDecl = resolveOpaqueTypeDecl(opaqueDescriptor);
+  if (!opaqueDecl)
+    return Type();
 
-    OpaqueTypeDecl *opaqueDecl = nullptr;
-    for (auto module : potentialParentModules)
-      if (auto decl = module->lookupOpaqueResultType(mangledName))
-        opaqueDecl = decl;
+  SmallVector<Type, 8> allArgs;
+  for (auto argSet : args) {
+    allArgs.append(argSet.begin(), argSet.end());
+  }
 
-    if (!opaqueDecl)
-      return Type();
-    SmallVector<Type, 8> allArgs;
-    for (auto argSet : args) {
-      allArgs.append(argSet.begin(), argSet.end());
-    }
+  if (ordinal >= opaqueDecl->getOpaqueGenericParams().size())
+    return Type();
 
-    SubstitutionMap subs = createSubstitutionMapFromGenericArgs(
-        opaqueDecl->getGenericSignature(), allArgs,
-        LookUpConformanceInModule());
-    Type interfaceType = opaqueDecl->getOpaqueGenericParams()[ordinal];
-    return OpaqueTypeArchetypeType::get(opaqueDecl, interfaceType, subs);
-  }
-  
-  // TODO: named opaque types
-  return Type();
+  SubstitutionMap subs = createSubstitutionMapFromGenericArgs(
+      opaqueDecl->getGenericSignature(), allArgs);
+  Type interfaceType = opaqueDecl->getOpaqueGenericParams()[ordinal];
+  return OpaqueTypeArchetypeType::get(opaqueDecl, interfaceType, subs);
 }
 
 Type ASTBuilder::createBoundGenericType(GenericTypeDecl *decl,
@@ -474,14 +598,13 @@ Type ASTBuilder::createFunctionType(
                                                  representation);
 
   // TODO: Handle LifetimeDependenceInfo here.
-  auto einfo =
-      FunctionType::ExtInfoBuilder(
-          representation, noescape, flags.isThrowing(), thrownError,
-          resultDiffKind, clangFunctionType, isolation,
-          /*LifetimeDependenceInfo*/ std::nullopt, extFlags.hasSendingResult())
-          .withAsync(flags.isAsync())
-          .withSendable(flags.isSendable())
-          .build();
+  auto einfo = FunctionType::ExtInfoBuilder(
+                   representation, noescape, flags.isThrowing(), thrownError,
+                   resultDiffKind, clangFunctionType, isolation,
+                   /*LifetimeDependenceInfo*/ {}, extFlags.hasSendingResult())
+                   .withAsync(flags.isAsync())
+                   .withSendable(flags.isSendable())
+                   .build();
 
   return FunctionType::get(funcParams, output, einfo);
 }
@@ -528,6 +651,16 @@ getParameterOptions(ImplParameterInfoOptions implOptions) {
     result |= SILParameterInfo::Sending;
   }
 
+  if (implOptions.contains(ImplParameterInfoFlags::Isolated)) {
+    implOptions -= ImplParameterInfoFlags::Isolated;
+    result |= SILParameterInfo::Isolated;
+  }
+
+  if (implOptions.contains(ImplParameterInfoFlags::ImplicitLeading)) {
+    implOptions -= ImplParameterInfoFlags::ImplicitLeading;
+    result |= SILParameterInfo::ImplicitLeading;
+  }
+
   // If we did not handle all flags in implOptions, this code was not updated
   // appropriately. Return None to signal error.
   if (bool(implOptions))
@@ -704,7 +837,7 @@ Type ASTBuilder::createImplFunctionType(
       SILFunctionType::ExtInfoBuilder(
           representation, flags.isPseudogeneric(), !flags.isEscaping(),
           flags.isSendable(), flags.isAsync(), unimplementable, isolation,
-          diffKind, clangFnType, /*LifetimeDependenceInfo*/ std::nullopt)
+          diffKind, clangFnType, /*LifetimeDependenceInfo*/ {})
           .build();
 
   return SILFunctionType::get(genericSig, einfo, funcCoroutineKind,
@@ -767,65 +900,91 @@ Type ASTBuilder::createExistentialMetatypeType(
 Type ASTBuilder::createConstrainedExistentialType(
     Type base, ArrayRef<BuiltRequirement> constraints,
     ArrayRef<BuiltInverseRequirement> inverseRequirements) {
-  Type constrainedBase;
-
-  if (auto baseTy = base->getAs<ProtocolType>()) {
-    auto baseDecl = baseTy->getDecl();
-    llvm::SmallDenseMap<Identifier, Type> cmap;
-    for (const auto &req : constraints) {
-      switch (req.getKind()) {
-      case RequirementKind::SameShape:
-        llvm_unreachable("Same-shape requirement not supported here");
-      case RequirementKind::Conformance:
-      case RequirementKind::Superclass:
-      case RequirementKind::Layout:
-        continue;
+  llvm::SmallDenseMap<AssociatedTypeDecl *, Type> primaryAssociatedTypes;
+  llvm::SmallDenseSet<AssociatedTypeDecl *> claimed;
+
+  for (const auto &req : constraints) {
+    switch (req.getKind()) {
+    case RequirementKind::SameShape:
+    case RequirementKind::Conformance:
+    case RequirementKind::Superclass:
+    case RequirementKind::Layout:
+      break;
+
+    case RequirementKind::SameType: {
+      if (auto *memberTy = req.getFirstType()->getAs<DependentMemberType>()) {
+        if (memberTy->getBase()->is<GenericTypeParamType>()) {
+          // This is the only case we understand so far.
+          if (auto *assocTy = memberTy->getAssocType())
+            primaryAssociatedTypes[assocTy] = req.getSecondType();
 
-      case RequirementKind::SameType:
-        if (auto *DMT = req.getFirstType()->getAs<DependentMemberType>())
-          cmap[DMT->getName()] = req.getSecondType();
+          continue;
+        }
       }
+      break;
     }
+    }
+
+    // If we end here, we didn't recognize this requirement.
+    return Type();
+  }
+
+  auto maybeFormParameterizedProtocolType = [&](ProtocolType *protoTy) -> Type {
+    auto *proto = protoTy->getDecl();
+
     llvm::SmallVector<Type, 4> args;
-    for (auto *assocTy : baseDecl->getPrimaryAssociatedTypes()) {
-      auto argTy = cmap.find(assocTy->getName());
-      if (argTy == cmap.end()) {
-        return Type();
+    for (auto *assocTy : proto->getPrimaryAssociatedTypes()) {
+      auto found = primaryAssociatedTypes.find(assocTy);
+      if (found != primaryAssociatedTypes.end()) {
+        args.push_back(found->second);
+        claimed.insert(found->first);
+        continue;
       }
-      args.push_back(argTy->getSecond());
     }
 
     // We may not have any arguments because the constrained existential is a
     // plain protocol with an inverse requirement.
-    if (args.empty()) {
-      constrainedBase =
-          ProtocolType::get(baseDecl, baseTy, base->getASTContext());
-    } else {
-      constrainedBase =
-          ParameterizedProtocolType::get(base->getASTContext(), baseTy, args);
-    }
-  } else if (base->isAny()) {
-    // The only other case should be that we got an empty PCT, which is equal to
-    // the Any type. The other constraints should have been encoded in the
-    // existential's generic signature (and arrive as BuiltInverseRequirement).
-    constrainedBase = base;
+    if (args.empty())
+      return protoTy;
+
+    return ParameterizedProtocolType::get(Ctx, protoTy, args);
+  };
+
+  SmallVector<Type, 2> members;
+  bool hasExplicitAnyObject = false;
+  InvertibleProtocolSet inverses;
+
+  // We're given either a single protocol type, or a composition of protocol
+  // types. Transform each protocol type to add arguments, if necessary.
+  if (auto protoTy = base->getAs<ProtocolType>()) {
+    members.push_back(maybeFormParameterizedProtocolType(protoTy));
   } else {
-    return Type();
+    auto compositionTy = base->castTo<ProtocolCompositionType>();
+    hasExplicitAnyObject = compositionTy->hasExplicitAnyObject();
+    ASSERT(compositionTy->getInverses().empty());
+
+    for (auto member : compositionTy->getMembers()) {
+      if (auto *protoTy = member->getAs<ProtocolType>()) {
+        members.push_back(maybeFormParameterizedProtocolType(protoTy));
+        continue;
+      }
+      ASSERT(member->getClassOrBoundGenericClass());
+      members.push_back(member);
+    }
   }
 
-  assert(constrainedBase);
+  // Make sure that all arguments were actually used.
+  ASSERT(claimed.size() == primaryAssociatedTypes.size());
 
   // Handle inverse requirements.
   if (!inverseRequirements.empty()) {
-    InvertibleProtocolSet inverseSet;
     for (const auto &inverseReq : inverseRequirements) {
-      inverseSet.insert(inverseReq.getKind());
+      inverses.insert(inverseReq.getKind());
     }
-    constrainedBase = ProtocolCompositionType::get(
-        Ctx, { constrainedBase }, inverseSet, /*hasExplicitAnyObject=*/false);
   }
 
-  return ExistentialType::get(constrainedBase);
+  return ExistentialType::get(ProtocolCompositionType::get(
+      Ctx, members, inverses, hasExplicitAnyObject));
 }
 
 Type ASTBuilder::createSymbolicExtendedExistentialType(NodePointer shapeNode,
@@ -979,8 +1138,7 @@ Type ASTBuilder::createSILBoxTypeWithLayout(
   SubstitutionMap substs;
   if (signature)
     substs = createSubstitutionMapFromGenericArgs(
-        signature, replacements,
-        LookUpConformanceInModule());
+        signature, replacements);
   return SILBoxType::get(Ctx, layout, substs);
 }
 
@@ -1162,9 +1320,17 @@ ASTBuilder::createTypeDecl(NodePointer node,
 }
 
 llvm::ArrayRef<ModuleDecl *>
-ASTBuilder::findPotentialModules(NodePointer node) {
+ASTBuilder::findPotentialModules(NodePointer node, ModuleDecl *&scratch) {
   assert(node->getKind() == Demangle::Node::Kind::Module);
+
   const auto moduleName = node->getText();
+
+  if (moduleName == CLANG_HEADER_MODULE_NAME) {
+    auto *importer = Ctx.getClangModuleLoader();
+    scratch = importer->getImportedHeaderModule();
+    return ArrayRef(&scratch, 1);
+  }
+
   return Ctx.getModulesByRealOrABIName(moduleName);
 }
 
@@ -1272,7 +1438,8 @@ ASTBuilder::findDeclContext(NodePointer node) {
     // debugger or USR together with the OriginallyDefinedIn attribute for
     // example.
     assert(false && "Looked up module as decl context directly!");
-    auto modules = findPotentialModules(node);
+    ModuleDecl *scratch;
+    auto modules = findPotentialModules(node, scratch);
     return modules.empty() ? nullptr : modules[0];
   }
 
@@ -1290,7 +1457,8 @@ ASTBuilder::findDeclContext(NodePointer node) {
       if (!moduleNode)
         return nullptr;
 
-      auto potentialModules = findPotentialModules(moduleNode);
+      ModuleDecl *scratch;
+      auto potentialModules = findPotentialModules(moduleNode, scratch);
       if (potentialModules.empty())
         return nullptr;
 
@@ -1310,22 +1478,8 @@ ASTBuilder::findDeclContext(NodePointer node) {
     StringRef name;
     StringRef relatedEntityKind;
     Identifier privateDiscriminator;
-    if (declNameNode->getKind() == Demangle::Node::Kind::Identifier) {
-      name = declNameNode->getText();
-
-    } else if (declNameNode->getKind() ==
-                 Demangle::Node::Kind::PrivateDeclName) {
-      name = declNameNode->getChild(1)->getText();
-      privateDiscriminator =
-          getIdentifier(declNameNode->getChild(0)->getText());
-
-    } else if (declNameNode->getKind() ==
-                 Demangle::Node::Kind::RelatedEntityDeclName) {
-      name = declNameNode->getChild(1)->getText();
-      relatedEntityKind = declNameNode->getFirstChild()->getText();
-
-    // Ignore any other decl-name productions for now.
-    } else {
+    if (!extractNameNodeInfo(Ctx, declNameNode, name, relatedEntityKind,
+                             privateDiscriminator)) {
       return nullptr;
     }
 
@@ -1340,7 +1494,8 @@ ASTBuilder::findDeclContext(NodePointer node) {
 
     auto child = node->getFirstChild();
     if (child->getKind() == Node::Kind::Module) {
-      auto potentialModules = findPotentialModules(child);
+      ModuleDecl *scratch;
+      auto potentialModules = findPotentialModules(child, scratch);
       if (potentialModules.empty())
         return nullptr;
 
@@ -1363,7 +1518,8 @@ ASTBuilder::findDeclContext(NodePointer node) {
     return findDeclContext(node->getChild(0));
 
   case Demangle::Node::Kind::Extension: {
-    auto moduleDecls = findPotentialModules(node->getFirstChild());
+    ModuleDecl *scratch;
+    auto moduleDecls = findPotentialModules(node->getFirstChild(), scratch);
     if (moduleDecls.empty())
       return nullptr;
 
@@ -1397,7 +1553,10 @@ ASTBuilder::findDeclContext(NodePointer node) {
     for (auto *ext : nominalDecl->getExtensions()) {
       bool found = false;
       for (ModuleDecl *module : moduleDecls) {
-        if (ext->getParentModule() == module) {
+        auto *extensionModule = ext->getParentModule();
+
+        if (extensionModule == module ||
+            extensionModule == module->getUnderlyingModuleIfOverlay()) {
           found = true;
           break;
         }
@@ -1563,26 +1722,5 @@ GenericTypeDecl *ASTBuilder::findForeignTypeDecl(StringRef name,
 }
 
 Identifier ASTBuilder::getIdentifier(StringRef name) {
-  if (name.size() > 1 && name.front() == '`' && name.back() == '`') {
-    // Raw identifiers have backticks affixed before mangling. We need to
-    // remove those before creating the Identifier for the AST, which doesn't
-    // encode the backticks.
-    std::string fixedName;
-    for (size_t i = 1; i < name.size() - 1; ++i) {
-      unsigned char ch = name[i];
-      // Raw identifiers have the space (U+0020) replaced with a non-breaking
-      // space (U+00A0, UTF-8: 0xC2 0xA0) in their mangling so that parts of
-      // the runtime that use space as a delimiter remain compatible with
-      // these identifiers. Flip it back.
-      if (ch == 0xc2 && i < name.size() - 2 &&
-          (unsigned char)name[i + 1] == 0xa0) {
-        fixedName.push_back(' ');
-        ++i;
-      } else {
-        fixedName.push_back(ch);
-      }
-    }
-    return Ctx.getIdentifier(fixedName);
-  }
-  return Ctx.getIdentifier(name);
+  return Demangle::getIdentifier(Ctx, name);
 }
diff --git a/lib/AST/ASTDumper.cpp b/lib/AST/ASTDumper.cpp
index adecada4369f0..c8bbe0dd5afd0 100644
--- a/lib/AST/ASTDumper.cpp
+++ b/lib/AST/ASTDumper.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -200,6 +200,33 @@ class escaping_ostream : public raw_ostream {
   virtual void anchor() override {}
 };
 
+/// Replaces any local archetypes in the given type with their equivalent
+/// existential upper bounds so that they can be passed to the AST mangler. This
+/// loses information but is probably sufficient for most questions about these
+/// types that consumers of the JSON AST would ask.
+Type replaceLocalArchetypesWithExistentials(Type type) {
+  return type.transformRec([&](TypeBase *t) -> std::optional<Type> {
+    if (auto LAT = dyn_cast<LocalArchetypeType>(t)) {
+      return LAT->getExistentialType();
+    }
+    return std::nullopt;
+  });
+}
+
+/// Replaces any opaque type archetypes in the given type with their equivalent
+/// existential upper bounds. This is used when dumping the mapping of all
+/// opaque types in the source file so that their conformances can be more
+/// easily reasoned about without having to find the declaring opaque result
+/// type deeper in the AST.
+Type replaceOpaqueArchetypesWithExistentials(Type type) {
+  return type.transformRec([&](TypeBase *t) -> std::optional<Type> {
+    if (auto OT = dyn_cast<OpaqueTypeArchetypeType>(t)) {
+      return OT->getExistentialType();
+    }
+    return std::nullopt;
+  });
+}
+
 /// Returns the USR of the given declaration. Gracefully returns an empty
 /// string if D is null or invalid.
 std::string declUSR(const Decl *D) {
@@ -234,14 +261,10 @@ std::string typeUSR(Type type) {
     return "";
 
   if (type->hasArchetype()) {
-    // We can't generate USRs for types that contain archetypes. Replace them
-    // with their interface types.
-    type = type.transformRec([&](TypeBase *t) -> std::optional<Type> {
-      if (auto AT = dyn_cast<ArchetypeType>(t)) {
-        return AT->getInterfaceType();
-      }
-      return std::nullopt;
-    });
+    type = type->mapTypeOutOfContext();
+  }
+  if (type->hasLocalArchetype()) {
+    type = replaceLocalArchetypesWithExistentials(type);
   }
 
   std::string usr;
@@ -305,6 +328,8 @@ static StringRef getDumpString(ReadImplKind kind) {
     return "read_coroutine";
   case ReadImplKind::Read2:
     return "read2_coroutine";
+  case ReadImplKind::Borrow:
+    return "borrow";
   }
   llvm_unreachable("bad kind");
 }
@@ -327,6 +352,8 @@ static StringRef getDumpString(WriteImplKind kind) {
     return "modify_coroutine";
   case WriteImplKind::Modify2:
     return "modify2_coroutine";
+  case WriteImplKind::Mutate:
+    return "mutate";
   }
   llvm_unreachable("bad kind");
 }
@@ -349,6 +376,8 @@ static StringRef getDumpString(ReadWriteImplKind kind) {
     return "stored_with_didset";
   case ReadWriteImplKind::InheritedWithDidSet:
     return "inherited_with_didset";
+  case ReadWriteImplKind::Mutate:
+    return "mutate";
   }
   llvm_unreachable("bad kind");
 }
@@ -552,6 +581,8 @@ static StringRef getDumpString(ExternKind kind) {
 }
 static StringRef getDumpString(InlineKind kind) {
   switch (kind) {
+  case InlineKind::AlwaysUnderscored:
+    return "__always";
   case InlineKind::Always:
     return "always";
   case InlineKind::Never:
@@ -618,14 +649,6 @@ static StringRef getDumpString(FunctionRefInfo::ApplyLevel applyLevel) {
     return "double_apply";
   }
 }
-static StringRef getDumpString(ExecutionKind kind) {
-  switch (kind) {
-  case ExecutionKind::Concurrent:
-    return "concurrent";
-  case ExecutionKind::Caller:
-    return "caller";
-  }
-}
 static StringRef getDumpString(ExplicitSafety safety) {
   switch (safety) {
   case ExplicitSafety::Unspecified:
@@ -636,6 +659,21 @@ static StringRef getDumpString(ExplicitSafety safety) {
     return "unsafe";
   }
 }
+static StringRef getDumpString(ConformanceEntryKind kind) {
+  switch (kind) {
+  case ConformanceEntryKind::Inherited:
+    return "inherited";
+  case ConformanceEntryKind::Explicit:
+    return "explicit";
+  case ConformanceEntryKind::PreMacroExpansion:
+    return "pre_macro_expansion";
+  case ConformanceEntryKind::Synthesized:
+    return "synthesized";
+  case ConformanceEntryKind::Implied:
+    return "implied";
+  }
+  llvm_unreachable("unhandled ConformanceEntryKind");
+}
 static StringRef getDumpString(StringRef s) {
   return s;
 }
@@ -775,8 +813,6 @@ namespace {
     virtual void printSourceRange(const SourceRange R, const ASTContext *Ctx,
                                   Label label) = 0;
 
-    virtual bool hasNonStandardOutput() const = 0;
-
     /// Indicates whether the output format is meant to be parsable. Parsable
     /// output should use structure rather than stringification to convey
     /// detailed information, and generally provides more information than the
@@ -870,10 +906,6 @@ namespace {
       }, label, RangeColor);
     }
 
-    bool hasNonStandardOutput() const override {
-      return &OS != &llvm::errs() && &OS != &llvm::dbgs();
-    }
-
     bool isParsable() const override { return false; }
   };
 
@@ -984,8 +1016,6 @@ namespace {
       OS.attributeEnd();
     }
 
-    bool hasNonStandardOutput() const override { return true; }
-
     bool isParsable() const override { return true; }
   };
 
@@ -1016,10 +1046,6 @@ namespace {
           GetTypeOfExpr(getTypeOfExpr), GetTypeOfTypeRepr(getTypeOfTypeRepr),
           GetTypeOfKeyPathComponent(getTypeOfKeyPathComponent) {}
 
-    bool hasNonStandardOutput() {
-      return Writer.hasNonStandardOutput();
-    }
-
     bool isTypeChecked() const {
       return MemberLoading == ASTDumpMemberLoading::TypeChecked;
     }
@@ -1060,7 +1086,7 @@ namespace {
       else if (auto *SubStmt = Elt.dyn_cast<Stmt*>())
         printRec(SubStmt, Ctx, label);
       else
-        printRec(Elt.get<Decl*>(), label);
+        printRec(cast<Decl *>(Elt), label);
     }
 
     /// Print a statement condition element as a child node.
@@ -1237,13 +1263,19 @@ namespace {
 
     /// Print a substitution map as a child node.
     void printRec(SubstitutionMap map, Label label) {
+      printRec(map, SubstitutionMap::DumpStyle::Full, label);
+    }
+
+    /// Print a substitution map as a child node.
+    void printRec(SubstitutionMap map, SubstitutionMap::DumpStyle style,
+                  Label label) {
       SmallPtrSet<const ProtocolConformance *, 4> Dumped;
-      printRec(map, Dumped, label);
+      printRec(map, style, Dumped, label);
     }
 
     /// Print a substitution map as a child node.
-    void printRec(SubstitutionMap map, VisitedConformances &visited,
-                  Label label);
+    void printRec(SubstitutionMap map, SubstitutionMap::DumpStyle style,
+                  VisitedConformances &visited, Label label);
 
     /// Print a substitution map as a child node.
     void printRec(const ProtocolConformanceRef &conf,
@@ -1259,6 +1291,40 @@ namespace {
     void printRec(const ProtocolConformance *conformance,
                   VisitedConformances &visited, Label label);
 
+    // Print a field that describes the actor isolation associated with an AST
+    // node.
+    void printIsolation(const ActorIsolation &isolation) {
+      switch (isolation) {
+      case ActorIsolation::Unspecified:
+      case ActorIsolation::NonisolatedUnsafe:
+        break;
+
+      case ActorIsolation::Nonisolated:
+        printFlag(true, "nonisolated", CapturesColor);
+        break;
+
+      case ActorIsolation::Erased:
+        printFlag(true, "dynamically_isolated", CapturesColor);
+        break;
+
+      case ActorIsolation::CallerIsolationInheriting:
+        printFlag(true, "isolated_to_caller_isolation", CapturesColor);
+        break;
+
+      case ActorIsolation::ActorInstance:
+        printReferencedDeclWithContextField(isolation.getActorInstance(),
+                                            Label::always("actor_isolated"),
+                                            CapturesColor);
+        break;
+
+      case ActorIsolation::GlobalActor:
+        printTypeField(isolation.getGlobalActor(),
+                       Label::always("global_actor_isolated"), PrintOptions(),
+                       CapturesColor);
+        break;
+      }
+    }
+
     /// Print a requirement node.
     void visitRequirement(const Requirement &requirement, Label label) {
       printHead("requirement", ASTNodeColor, label);
@@ -1270,13 +1336,19 @@ namespace {
 
       printField(requirement.getKind(), Label::optional("kind"));
 
-      if (requirement.getKind() != RequirementKind::Layout
-            && requirement.getSecondType())
-        printTypeField(requirement.getSecondType(),
-                       Label::optional("second_type"), opts);
-      else if (requirement.getLayoutConstraint())
+      switch (requirement.getKind()) {
+      case RequirementKind::Layout:
         printFieldQuoted(requirement.getLayoutConstraint(),
                          Label::optional("layout"));
+        break;
+      case RequirementKind::Conformance:
+        printReferencedDeclField(requirement.getProtocolDecl(),
+                                 Label::optional("protocol"));
+        break;
+      default:
+        printTypeField(requirement.getSecondType(),
+                       Label::optional("second_type"), opts);
+      }
 
       printFoot();
     }
@@ -1662,7 +1734,8 @@ namespace {
     /// Prints a type as a field. If writing a parsable output format, the
     /// `PrintOptions` are ignored and the type is written as a USR; otherwise,
     /// the type is stringified using the `PrintOptions`.
-    void printTypeField(Type Ty, Label label, PrintOptions opts = PrintOptions(),
+    void printTypeField(Type Ty, Label label,
+                        const PrintOptions &opts = PrintOptions(),
                         TerminalColor Color = TypeColor) {
       if (Writer.isParsable()) {
         printField(typeUSR(Ty), label, Color);
@@ -1870,7 +1943,7 @@ namespace {
         printWhereClause(GC->getTrailingWhereClause(),
                          Label::always("where_requirements"));
       } else {
-        const auto ATD = Owner.get<const AssociatedTypeDecl *>();
+        const auto ATD = cast<const AssociatedTypeDecl *>(Owner);
         printWhereClause(ATD->getTrailingWhereClause(),
                          Label::always("where_requirements"));
       }
@@ -1925,6 +1998,62 @@ namespace {
       }
     }
 
+    void printInheritance(const IterableDeclContext *DC) {
+      if (!(Writer.isParsable() && isTypeChecked())) {
+        // If the output is not parsable or we're not type-checked, just print
+        // the inheritance list as written.
+        switch (DC->getIterableContextKind()) {
+        case IterableDeclContextKind::NominalTypeDecl:
+          printInherited(cast<NominalTypeDecl>(DC)->getInherited());
+          break;
+        case IterableDeclContextKind::ExtensionDecl:
+          printInherited(cast<ExtensionDecl>(DC)->getInherited());
+          break;
+        }
+        return;
+      }
+
+      // For parsable, type-checked output, print a more structured
+      // representation of the data.
+      printRecArbitrary(
+          [&](Label label) {
+            printHead("inheritance", FieldLabelColor, label);
+
+            SmallPtrSet<const ProtocolConformance *, 4> dumped;
+            printList(
+                DC->getLocalConformances(),
+                [&](auto conformance, Label label) {
+                  printRec(conformance, dumped, label);
+                },
+                Label::always("conformances"));
+
+            if (auto CD = dyn_cast<ClassDecl>(DC); CD && CD->hasSuperclass()) {
+              printTypeField(CD->getSuperclass(),
+                             Label::always("superclass_type"));
+            }
+
+            if (auto ED = dyn_cast<EnumDecl>(DC); ED && ED->hasRawType()) {
+              printTypeField(ED->getRawType(), Label::always("raw_type"));
+            }
+
+            if (auto PD = dyn_cast<ProtocolDecl>(DC)) {
+              printList(
+                  PD->getAllInheritedProtocols(),
+                  [&](auto inherited, Label label) {
+                    printReferencedDeclField(inherited, label);
+                  },
+                  Label::always("protocols"));
+              if (PD->hasSuperclass()) {
+                printReferencedDeclField(PD->getSuperclassDecl(),
+                                         Label::always("superclass_decl_usr"));
+              }
+            }
+
+            printFoot();
+          },
+          Label::always("inherits"));
+    }
+
     void printInherited(InheritedTypes Inherited) {
       if (Writer.isParsable()) {
         printList(
@@ -2000,14 +2129,19 @@ namespace {
       printFoot();
     }
 
+    void visitUsingDecl(UsingDecl *UD, Label label) {
+      printCommon(UD, "using_decl", label);
+      printFieldQuoted(UD->getSpecifierName(), Label::always("specifier"));
+    }
+
     void visitExtensionDecl(ExtensionDecl *ED, Label label) {
       printCommon(ED, "extension_decl", label, ExtensionColor);
       printFlag(!ED->hasBeenBound(), "unbound");
       if (ED->hasBeenBound()) {
         printTypeField(ED->getExtendedType(), Label::optional("extended_type"));
-      } else {
+      } else if (auto *extTypeRepr = ED->getExtendedTypeRepr()) {
         printNameRaw([&](raw_ostream &OS) {
-          ED->getExtendedTypeRepr()->print(OS);
+          extTypeRepr->print(OS);
         }, Label::optional("extended_type"));
       }
       printCommonPost(ED);
@@ -2260,13 +2394,13 @@ namespace {
       switch (IDC->getIterableContextKind()) {
       case IterableDeclContextKind::NominalTypeDecl: {
         const auto NTD = cast<NominalTypeDecl>(IDC);
-        printInherited(NTD->getInherited());
+        printInheritance(NTD);
         printWhereRequirements(NTD);
         break;
       }
       case IterableDeclContextKind::ExtensionDecl:
         const auto ED = cast<ExtensionDecl>(IDC);
-        printInherited(ED->getInherited());
+        printInheritance(ED);
         printWhereRequirements(ED);
         break;
       }
@@ -2297,6 +2431,27 @@ namespace {
       printFoot();
     }
 
+    // Prints a mapping from the declared interface types of the opaque types to
+    // their equivalent existential type. This loses some information, but it is
+    // meant to make it easier to determine which protocols an opaque type
+    // conforms to when such a type appears elsewhere in an expression dump,
+    // farther away from where the opaque type is declared.
+    void printOpaqueTypeMapping(ArrayRef<OpaqueTypeDecl *> opaqueDecls) {
+      printRecArbitrary(
+          [&](Label label) {
+            printHead("opaque_to_existential_mapping", FieldLabelColor, label);
+            for (const auto OTD : opaqueDecls) {
+              Type interfaceType = OTD->getDeclaredInterfaceType();
+              Type existentialType =
+                  replaceOpaqueArchetypesWithExistentials(interfaceType);
+              printTypeField(existentialType,
+                             Label::always(typeUSR(interfaceType)));
+            }
+            printFoot();
+          },
+          Label::always("opaque_to_existential_mapping"));
+    }
+
     void visitSourceFile(const SourceFile &SF) {
       Writer.setMainBufferID(SF.getBufferID());
 
@@ -2360,11 +2515,20 @@ namespace {
             } else if (auto stmt = item.dyn_cast<Stmt *>()) {
               printRec(stmt, &SF.getASTContext(), label);
             } else {
-              auto expr = item.get<Expr *>();
+              auto expr = cast<Expr *>(item);
               printRec(expr, label);
             }
           },
           Label::optional("items"));
+
+      if (Writer.isParsable() && isTypeChecked()) {
+        SmallVector<OpaqueTypeDecl *, 4> opaqueDecls;
+        SF.getOpaqueReturnTypeDecls(opaqueDecls);
+        if (!opaqueDecls.empty()) {
+          printOpaqueTypeMapping(opaqueDecls);
+        }
+      }
+
       printFoot();
     }
 
@@ -2391,6 +2555,8 @@ namespace {
               VD->getAttrs().getAttribute<NonisolatedAttr>()) {
         if (nonisolatedAttr->isUnsafe()) {
           printFlag(true, "nonisolated(unsafe)", DeclModifierColor);
+        } else if (nonisolatedAttr->isNonSending()) {
+          printFlag(true, "nonisolated(nonsending)", DeclModifierColor);
         } else {
           printFlag(true, "nonisolated", DeclModifierColor);
         }
@@ -2857,11 +3023,6 @@ void swift::printContext(raw_ostream &os, DeclContext *dc) {
         << "autoclosure discriminator=";
     }
 
-    // If we aren't printing to standard error or the debugger output stream,
-    // this client expects to see the computed discriminator. Compute it now.
-    if (&os != &llvm::errs() && &os != &llvm::dbgs())
-      (void)ACE->getDiscriminator();
-
     PrintWithColorRAII(os, DiscriminatorColor) << ACE->getRawDiscriminator();
     break;
   }
@@ -2922,7 +3083,14 @@ void ValueDecl::dumpRef(raw_ostream &os) const {
     printContext(os, getDeclContext());
     os << ".";
     // Print name.
-    getName().printPretty(os);
+    if (auto accessor = dyn_cast<AccessorDecl>(this)) {
+      // If it's an accessor, print the name of the storage and then the
+      // accessor kind.
+      accessor->getStorage()->getName().printPretty(os);
+      os << "." << Decl::getDescriptiveKindName(accessor->getDescriptiveKind());
+    } else {
+      getName().printPretty(os);
+    }
   } else {
     auto moduleName = cast<ModuleDecl>(this)->getRealName();
     os << moduleName;
@@ -3232,13 +3400,11 @@ class PrintExpr : public ExprVisitor<PrintExpr, void, Label>,
   /// FIXME: This should use ExprWalker to print children.
 
   void printCommon(Expr *E, const char *C, Label label) {
-    PrintOptions PO;
-    PO.PrintTypesForDebugging = true;
-
     printHead(C, ExprColor, label);
 
     printFlag(E->isImplicit(), "implicit", ExprModifierColor);
-    printTypeField(GetTypeOfExpr(E), Label::always("type"), PO, TypeColor);
+    printTypeField(GetTypeOfExpr(E), Label::always("type"),
+                   PrintOptions::forDebugging(), TypeColor);
 
     // If we have a source range and an ASTContext, print the source range.
     if (auto Ty = GetTypeOfExpr(E)) {
@@ -3265,6 +3431,8 @@ class PrintExpr : public ExprVisitor<PrintExpr, void, Label>,
 
   void visitErrorExpr(ErrorExpr *E, Label label) {
     printCommon(E, "error_expr", label);
+    if (auto *origExpr = E->getOriginalExpr())
+      printRec(origExpr, Label::optional("original_expr"));
     printFoot();
   }
 
@@ -3649,12 +3817,6 @@ class PrintExpr : public ExprVisitor<PrintExpr, void, Label>,
 
     printFoot();
   }
-  void visitUnresolvedTypeConversionExpr(UnresolvedTypeConversionExpr *E,
-                                         Label label) {
-    printCommon(E, "unresolvedtype_conversion_expr", label);
-    printRec(E->getSubExpr(), Label::optional("sub_expr"));
-    printFoot();
-  }
   void visitFunctionConversionExpr(FunctionConversionExpr *E, Label label) {
     printCommon(E, "function_conversion_expr", label);
     printRec(E->getSubExpr(), Label::optional("sub_expr"));
@@ -3892,10 +4054,8 @@ class PrintExpr : public ExprVisitor<PrintExpr, void, Label>,
   void visitForceTryExpr(ForceTryExpr *E, Label label) {
     printCommon(E, "force_try_expr", label);
 
-    PrintOptions PO;
-    PO.PrintTypesForDebugging = true;
-    printTypeField(E->getThrownError(), Label::always("thrown_error"), PO,
-                   TypeColor);
+    printTypeField(E->getThrownError(), Label::always("thrown_error"),
+                   PrintOptions::forDebugging(), TypeColor);
 
     printRec(E->getSubExpr(), Label::optional("sub_expr"));
     printFoot();
@@ -3904,10 +4064,8 @@ class PrintExpr : public ExprVisitor<PrintExpr, void, Label>,
   void visitOptionalTryExpr(OptionalTryExpr *E, Label label) {
     printCommon(E, "optional_try_expr", label);
 
-    PrintOptions PO;
-    PO.PrintTypesForDebugging = true;
-    printTypeField(E->getThrownError(), Label::always("thrown_error"), PO,
-                   TypeColor);
+    printTypeField(E->getThrownError(), Label::always("thrown_error"),
+                   PrintOptions::forDebugging(), TypeColor);
 
     printRec(E->getSubExpr(), Label::optional("sub_expr"));
     printFoot();
@@ -3936,47 +4094,17 @@ class PrintExpr : public ExprVisitor<PrintExpr, void, Label>,
     printFoot();
   }
 
-  void printClosure(AbstractClosureExpr *E, char const *name,
-                                  Label label) {
+  void printClosure(AbstractClosureExpr *E, char const *name, Label label) {
     printCommon(E, name, label);
 
-    // If we aren't printing to standard error or the debugger output stream,
-    // this client expects to see the computed discriminator. Compute it now.
-    if (hasNonStandardOutput())
-      (void)E->getDiscriminator();
+    // If we're dumping the type-checked AST, compute the discriminator if
+    // needed. Otherwise, print the cached discriminator.
+    auto discriminator = isTypeChecked() ? E->getDiscriminator()
+                                         : E->getRawDiscriminator();
 
-    printField(E->getRawDiscriminator(), Label::always("discriminator"),
+    printField(discriminator, Label::always("discriminator"),
                DiscriminatorColor);
-
-    switch (auto isolation = E->getActorIsolation()) {
-    case ActorIsolation::Unspecified:
-    case ActorIsolation::NonisolatedUnsafe:
-      break;
-
-    case ActorIsolation::Nonisolated:
-      printFlag(true, "nonisolated", CapturesColor);
-      break;
-
-    case ActorIsolation::Erased:
-      printFlag(true, "dynamically_isolated", CapturesColor);
-      break;
-
-    case ActorIsolation::CallerIsolationInheriting:
-      printFlag(true, "isolated_to_caller_isolation", CapturesColor);
-      break;
-
-    case ActorIsolation::ActorInstance:
-      printReferencedDeclWithContextField(isolation.getActorInstance(),
-                                          Label::always("actor_isolated"),
-                                          CapturesColor);
-      break;
-
-    case ActorIsolation::GlobalActor:
-      printTypeField(isolation.getGlobalActor(),
-                     Label::always("global_actor_isolated"), PrintOptions(),
-                     CapturesColor);
-      break;
-    }
+    printIsolation(E->getActorIsolation());
 
     if (auto captureInfo = E->getCachedCaptureInfo()) {
       printCaptureInfoField(captureInfo, Label::optional("captures"));
@@ -4368,6 +4496,12 @@ class PrintExpr : public ExprVisitor<PrintExpr, void, Label>,
   void visitSingleValueStmtExpr(SingleValueStmtExpr *E, Label label) {
     printCommon(E, "single_value_stmt_expr", label);
     printDeclContext(E);
+    if (auto preamble = E->getForExpressionPreamble()) {
+      printRec(preamble->ForAccumulatorDecl,
+               Label::optional("for_preamble_accumulator_decl"));
+      printRec(preamble->ForAccumulatorBinding,
+               Label::optional("for_preamble_accumulator_binding"));
+    }
     printRec(E->getStmt(), &E->getDeclContext()->getASTContext(),
              Label::optional("stmt"));
     printFoot();
@@ -4421,10 +4555,8 @@ class PrintExpr : public ExprVisitor<PrintExpr, void, Label>,
   void visitTypeValueExpr(TypeValueExpr *E, Label label) {
     printCommon(E, "type_value_expr", label);
 
-    PrintOptions PO;
-    PO.PrintTypesForDebugging = true;
-    printTypeField(E->getParamType(), Label::always("param_type"), PO,
-                   TypeColor);
+    printTypeField(E->getParamType(), Label::always("param_type"),
+                   PrintOptions::forDebugging(), TypeColor);
 
     printFoot();
   }
@@ -4487,6 +4619,8 @@ class PrintTypeRepr : public TypeReprVisitor<PrintTypeRepr, void, Label>,
 
   void visitErrorTypeRepr(ErrorTypeRepr *T, Label label) {
     printCommon("type_error", label);
+    if (auto *originalExpr = T->getOriginalExpr())
+      printRec(originalExpr, Label::optional("original_expr"));
   }
 
   void visitAttributedTypeRepr(AttributedTypeRepr *T, Label label) {
@@ -4646,6 +4780,12 @@ class PrintTypeRepr : public TypeReprVisitor<PrintTypeRepr, void, Label>,
     printFoot();
   }
 
+  void visitCallerIsolatedTypeRepr(CallerIsolatedTypeRepr *T, Label label) {
+    printCommon("caller_isolated", label);
+    printRec(T->getBase(), Label::optional("base"));
+    printFoot();
+  }
+
   void visitCompileTimeLiteralTypeRepr(CompileTimeLiteralTypeRepr *T, Label label) {
     printCommon("_const", label);
     printRec(T->getBase(), Label::optional("base"));
@@ -4859,7 +4999,6 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
   TRIVIAL_ATTR_PRINTER(ImplicitSelfCapture, implicit_self_capture)
   TRIVIAL_ATTR_PRINTER(Indirect, indirect)
   TRIVIAL_ATTR_PRINTER(Infix, infix)
-  TRIVIAL_ATTR_PRINTER(InheritActorContext, inherit_actor_context)
   TRIVIAL_ATTR_PRINTER(InheritsConvenienceInitializers,
                        inherits_convenience_initializers)
   TRIVIAL_ATTR_PRINTER(Inlinable, inlinable)
@@ -4876,6 +5015,7 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
   TRIVIAL_ATTR_PRINTER(NSApplicationMain, ns_application_main)
   TRIVIAL_ATTR_PRINTER(NSCopying, ns_copying)
   TRIVIAL_ATTR_PRINTER(NSManaged, ns_managed)
+  TRIVIAL_ATTR_PRINTER(NeverEmitIntoClient, never_emit_into_client)
   TRIVIAL_ATTR_PRINTER(NoAllocation, no_allocation)
   TRIVIAL_ATTR_PRINTER(NoDerivative, no_derivative)
   TRIVIAL_ATTR_PRINTER(NoEagerMove, no_eager_move)
@@ -4884,6 +5024,7 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
   TRIVIAL_ATTR_PRINTER(NoLocks, no_locks)
   TRIVIAL_ATTR_PRINTER(NoMetadata, no_metadata)
   TRIVIAL_ATTR_PRINTER(NoObjCBridging, no_objc_bridging)
+  TRIVIAL_ATTR_PRINTER(ManualOwnership, manual_ownership)
   TRIVIAL_ATTR_PRINTER(NoRuntime, no_runtime)
   TRIVIAL_ATTR_PRINTER(NonEphemeral, non_ephemeral)
   TRIVIAL_ATTR_PRINTER(NonEscapable, non_escapable)
@@ -4925,14 +5066,12 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
   TRIVIAL_ATTR_PRINTER(Used, used)
   TRIVIAL_ATTR_PRINTER(WarnUnqualifiedAccess, warn_unqualified_access)
   TRIVIAL_ATTR_PRINTER(WeakLinked, weak_linked)
+  TRIVIAL_ATTR_PRINTER(Nonexhaustive, nonexhaustive)
+  TRIVIAL_ATTR_PRINTER(Concurrent, concurrent)
+  TRIVIAL_ATTR_PRINTER(UnsafeSelfDependentResult, unsafe_self_dependent_result)
 
 #undef TRIVIAL_ATTR_PRINTER
 
-  void visitExecutionAttr(ExecutionAttr *Attr, Label label) {
-    printCommon(Attr, "execution_attr", label);
-    printField(Attr->getBehavior(), Label::always("behavior"));
-    printFoot();
-  }
   void visitABIAttr(ABIAttr *Attr, Label label) {
     printCommon(Attr, "abi_attr", label);
     printRec(Attr->abiDecl, Label::always("decl"));
@@ -5002,9 +5141,10 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
   }
   void visitBackDeployedAttr(BackDeployedAttr *Attr, Label label) {
     printCommon(Attr, "back_deployed_attr", label);
-    printField(Attr->Platform, Label::always("platform"));
-    printFieldRaw([&](auto &out) { out << Attr->Version.getAsString(); },
-                  Label::always("version"));
+    printField(Attr->getPlatform(), Label::always("platform"));
+    printFieldRaw(
+        [&](auto &out) { out << Attr->getParsedVersion().getAsString(); },
+        Label::always("version"));
     printFoot();
   }
   void visitCDeclAttr(CDeclAttr *Attr, Label label) {
@@ -5183,6 +5323,13 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
   void visitNonisolatedAttr(NonisolatedAttr *Attr, Label label) {
     printCommon(Attr, "nonisolated_attr", label);
     printFlag(Attr->isUnsafe(), "unsafe");
+    printFlag(Attr->isNonSending(), "nonsending");
+    printFoot();
+  }
+  void visitInheritActorContextAttr(InheritActorContextAttr *Attr,
+                                    Label label) {
+    printCommon(Attr, "inherit_actor_context_attr", label);
+    printFlag(Attr->isAlways(), "always");
     printFoot();
   }
   void visitObjCAttr(ObjCAttr *Attr, Label label) {
@@ -5221,11 +5368,12 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
   void visitOriginallyDefinedInAttr(OriginallyDefinedInAttr *Attr,
                                     Label label) {
     printCommon(Attr, "originally_defined_in_attr", label);
-    printField(Attr->ManglingModuleName, Label::always("mangling_module"));
-    printField(Attr->LinkerModuleName, Label::always("linker_module"));
-    printField(Attr->Platform, Label::always("platform"));
-    printFieldRaw([&](auto &out) { out << Attr->MovedVersion.getAsString(); },
-                  Label::always("moved_version"));
+    printField(Attr->getManglingModuleName(), Label::always("mangling_module"));
+    printField(Attr->getLinkerModuleName(), Label::always("linker_module"));
+    printField(Attr->getPlatform(), Label::always("platform"));
+    printFieldRaw(
+        [&](auto &out) { out << Attr->getParsedMovedVersion().getAsString(); },
+        Label::always("moved_version"));
     printFoot();
   }
   void visitPrivateImportAttr(PrivateImportAttr *Attr, Label label) {
@@ -5309,7 +5457,16 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
     printFoot();
   }
   void visitSpecializeAttr(SpecializeAttr *Attr, Label label) {
-    printCommon(Attr, "specialize_attr", label);
+    visitAbstractSpecializeAttr(Attr, label);
+  }
+
+  void visitSpecializedAttr(SpecializedAttr *Attr, Label label) {
+    visitAbstractSpecializeAttr(Attr, label);
+  }
+
+  void visitAbstractSpecializeAttr(AbstractSpecializeAttr *Attr, Label label) {
+    printCommon(Attr, Attr->isPublic() ? "specialized_attr" :
+                  "specialize_attr", label);
     printFlag(Attr->isExported(), "exported");
     printFlag(Attr->isFullSpecialization(), "full");
     printFlag(Attr->isPartialSpecialization(), "partial");
@@ -5554,6 +5711,9 @@ class PrintConformance : public PrintBase {
       printTypeField(conformance->getType(), Label::always("type"));
       printReferencedDeclField(conformance->getProtocol(),
                                Label::always("protocol"));
+      printField(conformance->getSourceKind(), Label::optional("source_kind"));
+      printFlag(conformance->isRetroactive(), "retroactive");
+      printIsolation(conformance->getIsolation());
       if (!Writer.isParsable())
         printFlag(!shouldPrintDetails, "<details printed above>");
     };
@@ -5563,6 +5723,16 @@ class PrintConformance : public PrintBase {
         auto normal = cast<NormalProtocolConformance>(conformance);
 
         printCommon("normal_conformance");
+        printFlag(normal->isPreconcurrency(), "preconcurrency");
+        if (normal->isPreconcurrency() && normal->isComplete()) {
+          printFlag(normal->isPreconcurrencyEffectful(),
+                    "effectful_preconcurrency");
+        }
+        printFlag(normal->isRetroactive(), "retroactive");
+        printFlag(normal->isUnchecked(), "unchecked");
+        if (normal->getExplicitSafety() != ExplicitSafety::Unspecified)
+          printField(normal->getExplicitSafety(), Label::always("safety"));
+
         if (!shouldPrintDetails)
           break;
 
@@ -5657,7 +5827,8 @@ class PrintConformance : public PrintBase {
         if (!shouldPrintDetails)
           break;
 
-        printRec(conf->getSubstitutionMap(), visited,
+        printRec(conf->getSubstitutionMap(),
+                 SubstitutionMap::DumpStyle::Full, visited,
                  Label::optional("substitutions"));
         if (auto condReqs = conf->getConditionalRequirementsIfAvailableOrCached(/*computeIfPossible=*/false)) {
           printList(*condReqs, [&](auto subReq, Label label) {
@@ -5756,7 +5927,7 @@ class PrintConformance : public PrintBase {
 
     // A minimal dump doesn't need the details about the conformances, a lot of
     // that info can be inferred from the signature.
-    if (style == SubstitutionMap::DumpStyle::Minimal)
+    if (style != SubstitutionMap::DumpStyle::Full)
       return;
 
     auto conformances = map.getConformances();
@@ -5775,29 +5946,34 @@ class PrintConformance : public PrintBase {
   }
 };
 
-void PrintBase::printRec(SubstitutionMap map, VisitedConformances &visited,
-                         Label label) {
-  printRecArbitrary([&](Label label) {
-    PrintConformance(Writer)
-        .visitSubstitutionMap(map, SubstitutionMap::DumpStyle::Full, visited,
-                              label);
-  }, label);
+void PrintBase::printRec(SubstitutionMap map, SubstitutionMap::DumpStyle style,
+                         VisitedConformances &visited, Label label) {
+  printRecArbitrary(
+      [&](Label label) {
+        PrintConformance(Writer, MemberLoading)
+            .visitSubstitutionMap(map, style, visited, label);
+      },
+      label);
 }
 
 void PrintBase::printRec(const ProtocolConformanceRef &ref,
                          VisitedConformances &visited, Label label) {
-  printRecArbitrary([&](Label label) {
-    PrintConformance(Writer)
-          .visitProtocolConformanceRef(ref, visited, label);
-  }, label);
+  printRecArbitrary(
+      [&](Label label) {
+        PrintConformance(Writer, MemberLoading)
+            .visitProtocolConformanceRef(ref, visited, label);
+      },
+      label);
 }
 
 void PrintBase::printRec(const ProtocolConformance *conformance,
                          VisitedConformances &visited, Label label) {
-  printRecArbitrary([&](Label label) {
-    PrintConformance(Writer)
-        .visitProtocolConformance(conformance, visited, label);
-  }, label);
+  printRecArbitrary(
+      [&](Label label) {
+        PrintConformance(Writer, MemberLoading)
+            .visitProtocolConformance(conformance, visited, label);
+      },
+      label);
 }
 
 } // end anonymous namespace
@@ -5893,8 +6069,6 @@ namespace {
       printFoot();
     }
 
-    TRIVIAL_TYPE_PRINTER(Unresolved, unresolved)
-
     void visitPlaceholderType(PlaceholderType *T, Label label) {
       printCommon("placeholder_type", label);
       auto originator = T->getOriginator();
@@ -5903,12 +6077,16 @@ namespace {
       } else if (auto *VD = originator.dyn_cast<VarDecl *>()) {
         printFieldQuotedRaw([&](raw_ostream &OS) { VD->dumpRef(OS); },
                             Label::optional("originating_var"), DeclColor);
-      } else if (originator.is<ErrorExpr *>()) {
+      } else if (isa<ErrorExpr *>(originator)) {
         printFlag("error_expr");
+      } else if (auto *errTy = originator.dyn_cast<ErrorType *>()) {
+        printRec(errTy, Label::always("error_type"));
       } else if (auto *DMT = originator.dyn_cast<DependentMemberType *>()) {
         printRec(DMT, Label::always("dependent_member_type"));
-      } else if (originator.is<TypeRepr *>()) {
+      } else if (isa<TypeRepr *>(originator)) {
         printFlag("type_repr");
+      } else if (isa<Pattern *>(originator)) {
+        printFlag("pattern");
       } else {
         assert(false && "unknown originator");
       }
@@ -6198,7 +6376,9 @@ namespace {
 
       printArchetypeCommonRec(T);
       if (!T->getSubstitutions().empty()) {
-        printRec(T->getSubstitutions(), Label::optional("substitutions"));
+        printRec(T->getSubstitutions(),
+                 SubstitutionMap::DumpStyle::NoConformances,
+                 Label::optional("substitutions"));
       }
 
       printFoot();
@@ -6339,8 +6519,8 @@ namespace {
         case FunctionTypeIsolation::Kind::Erased:
           printFlag("@isolated(any)");
           break;
-        case FunctionTypeIsolation::Kind::NonIsolatedCaller:
-          printFlag("@execution(caller)");
+        case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
+          printFlag("nonisolated(nonsending)");
           break;
         }
       }
@@ -6532,6 +6712,7 @@ namespace {
       printCommon("integer_type", label);
       printFlag(T->isNegative(), "is_negative");
       printFieldQuoted(T->getValue(), Label::always("value"), LiteralValueColor);
+      printFieldQuoted(T->getDigitsText(), Label::always("text"), IdentifierColor);
       printFoot();
     }
 
@@ -6592,7 +6773,7 @@ void GenericEnvironment::dump() const {
 
 StringRef swift::getAccessorKindString(AccessorKind value) {
   switch (value) {
-#define ACCESSOR(ID)
+#define ACCESSOR(ID, KEYWORD)
 #define SINGLETON_ACCESSOR(ID, KEYWORD) \
   case AccessorKind::ID: return #KEYWORD;
 #include "swift/AST/AccessorKinds.def"
@@ -6648,7 +6829,7 @@ void RequirementRepr::dump() const {
 }
 
 void GenericParamList::dump() const {
-  print(llvm::errs());
+  print(llvm::errs(), PrintOptions::forDebugging());
   llvm::errs() << '\n';
 }
 
@@ -6657,11 +6838,11 @@ void LayoutConstraint::dump() const {
     llvm::errs() << "(null)\n";
     return;
   }
-  getPointer()->print(llvm::errs());
+  getPointer()->print(llvm::errs(), PrintOptions::forDebugging());
 }
 
 void GenericSignature::dump() const {
-  print(llvm::errs());
+  print(llvm::errs(), PrintOptions::forDebugging());
   llvm::errs() << '\n';
 }
 
@@ -6696,7 +6877,7 @@ void InheritedEntry::dump(llvm::raw_ostream &os) const {
     os << '@' << getDumpString(getExplicitSafety()) << ' ';
   if (isSuppressed())
     os << "~";
-  getType().print(os);
+  getType().print(os, PrintOptions::forDebugging());
 }
 
 void InheritedEntry::dump() const { dump(llvm::errs()); }
diff --git a/lib/AST/ASTMangler.cpp b/lib/AST/ASTMangler.cpp
index 6cab5461b47b0..909252e24ce90 100644
--- a/lib/AST/ASTMangler.cpp
+++ b/lib/AST/ASTMangler.cpp
@@ -49,6 +49,7 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Attr.h"
 #include "clang/AST/Decl.h"
+#include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/Mangle.h"
@@ -160,6 +161,10 @@ static StringRef getCodeForAccessorKind(AccessorKind kind) {
     return "x";
   case AccessorKind::Read2:
     return "y";
+  case AccessorKind::Borrow:
+    return "b";
+  case AccessorKind::Mutate:
+    return "z";
   }
   llvm_unreachable("bad accessor kind");
 }
@@ -252,6 +257,16 @@ std::string ASTMangler::mangleBackingInitializerEntity(const VarDecl *var,
   return finalize();
 }
 
+std::string
+ASTMangler::manglePropertyWrappedFieldInitAccessorEntity(const VarDecl *var,
+                                                         SymbolKind SKind) {
+  llvm::SaveAndRestore X(AllowInverses, inversesAllowed(var));
+  beginMangling();
+  appendPropertyWrappedFieldInitAccessorEntity(var);
+  appendSymbolKind(SKind);
+  return finalize();
+}
+
 std::string ASTMangler::mangleInitFromProjectedValueEntity(const VarDecl *var,
                                                            SymbolKind SKind) {
   llvm::SaveAndRestore X(AllowInverses, inversesAllowed(var));
@@ -299,7 +314,7 @@ std::string ASTMangler::mangleWitnessTable(const ProtocolConformance *C) {
   if (auto *sc = dyn_cast<SpecializedProtocolConformance>(C)) {
     appendProtocolConformance(sc);
     appendOperator("WP");
-  } else if (isa<NormalProtocolConformance>(C)) {
+  } else if (isa<NormalProtocolConformance>(C) || isa<InheritedProtocolConformance>(C)) {
     appendProtocolConformance(C);
     appendOperator("WP");
   } else if (isa<SelfProtocolConformance>(C)) {
@@ -395,7 +410,7 @@ std::string ASTMangler::mangleKeyPathGetterThunkHelper(
       sub = sub.transformRec([](Type t) -> std::optional<Type> {
         if (auto *openedExistential = t->getAs<ExistentialArchetypeType>()) {
           auto &ctx = openedExistential->getASTContext();
-          return GenericTypeParamType::getType(0, 0, ctx);
+          return ctx.TheSelfType;
         }
         return std::nullopt;
       });
@@ -431,7 +446,7 @@ std::string ASTMangler::mangleKeyPathSetterThunkHelper(
       sub = sub.transformRec([](Type t) -> std::optional<Type> {
         if (auto *openedExistential = t->getAs<ExistentialArchetypeType>()) {
           auto &ctx = openedExistential->getASTContext();
-          return GenericTypeParamType::getType(0, 0, ctx);
+          return ctx.TheSelfType;
         }
         return std::nullopt;
       });
@@ -945,6 +960,8 @@ std::string ASTMangler::mangleObjCRuntimeName(const NominalTypeDecl *Nominal) {
 
 std::string ASTMangler::mangleTypeAsContextUSR(const NominalTypeDecl *type) {
   beginManglingWithoutPrefix();
+  llvm::SaveAndRestore<bool> respectOriginallyDefinedInRAII(
+      RespectOriginallyDefinedIn, false);
   llvm::SaveAndRestore<bool> allowUnnamedRAII(AllowNamelessEntities, true);
   BaseEntitySignature base(type);
   appendContext(type, base, type->getAlternateModuleName());
@@ -1006,13 +1023,15 @@ ASTMangler::mangleAnyDecl(const ValueDecl *Decl,
 
   // We have a custom prefix, so finalize() won't verify for us. If we're not
   // in invalid code (coming from an IDE caller) verify manually.
-  if (!Decl->isInvalid())
+  if (CONDITIONAL_ASSERT_enabled() && !prefix && !Decl->isInvalid())
     verify(Storage.str(), Flavor);
   return finalize();
 }
 
 std::string ASTMangler::mangleDeclAsUSR(const ValueDecl *Decl,
                                         StringRef USRPrefix) {
+  llvm::SaveAndRestore<bool> respectOriginallyDefinedInRAII(
+      RespectOriginallyDefinedIn, false);
   return (llvm::Twine(USRPrefix) + mangleAnyDecl(Decl, false)).str();
 }
 
@@ -1021,12 +1040,14 @@ std::string ASTMangler::mangleAccessorEntityAsUSR(AccessorKind kind,
                                                   StringRef USRPrefix,
                                                   bool isStatic) {
   beginManglingWithoutPrefix();
+  llvm::SaveAndRestore<bool> respectOriginallyDefinedInRAII(
+      RespectOriginallyDefinedIn, false);
   llvm::SaveAndRestore<bool> allowUnnamedRAII(AllowNamelessEntities, true);
   Buffer << USRPrefix;
   appendAccessorEntity(getCodeForAccessorKind(kind), decl, isStatic);
   // We have a custom prefix, so finalize() won't verify for us. If we're not
   // in invalid code (coming from an IDE caller) verify manually.
-  if (!decl->isInvalid())
+  if (CONDITIONAL_ASSERT_enabled() && !decl->isInvalid())
     verify(Storage.str().drop_front(USRPrefix.size()), Flavor);
   return finalize();
 }
@@ -1199,7 +1220,8 @@ getOverriddenSwiftProtocolObjCName(const ValueDecl *decl,
   return std::nullopt;
 }
 
-void ASTMangler::appendDeclName(const ValueDecl *decl, DeclBaseName name) {
+void ASTMangler::appendDeclName(const ValueDecl *decl, DeclBaseName name,
+                                bool skipLocalDiscriminator) {
   ASSERT(!getABIDecl(decl) && "caller should make sure we get ABI decls");
   if (name.empty())
     name = decl->getBaseName();
@@ -1240,6 +1262,11 @@ void ASTMangler::appendDeclName(const ValueDecl *decl, DeclBaseName name) {
   }
 
   if (decl->getDeclContext()->isLocalContext()) {
+    // If we don't need a local discriminator (attached macros receive a
+    // separate discriminator), we're done.
+    if (skipLocalDiscriminator)
+      return;
+
     if (auto *paramDecl = dyn_cast<ParamDecl>(decl)) {
       if (!decl->hasName()) {
         // Mangle unnamed params with their ordering.
@@ -1390,7 +1417,6 @@ void ASTMangler::appendType(Type type, GenericSignature sig,
       llvm_unreachable("Cannot mangle module type yet");
 
     case TypeKind::Error:
-    case TypeKind::Unresolved:
     case TypeKind::Placeholder:
       appendOperator("Xe");
       return;
@@ -1440,8 +1466,7 @@ void ASTMangler::appendType(Type type, GenericSignature sig,
     case TypeKind::BuiltinUnsafeValueBuffer:
       return appendOperator("BB");
     case TypeKind::BuiltinUnboundGeneric:
-      llvm::errs() << "Don't know how to mangle a BuiltinUnboundGenericType\n";
-      abort();
+      ABORT("Don't know how to mangle a BuiltinUnboundGenericType");
     case TypeKind::Locatable: {
       auto loc = cast<LocatableType>(tybase);
       return appendType(loc->getSinglyDesugaredType(), sig, forDecl);
@@ -1607,7 +1632,7 @@ void ASTMangler::appendType(Type type, GenericSignature sig,
       // ExtendedExistentialTypeShapes consider existential metatypes to
       // be part of the existential, so if we're symbolically referencing
       // shapes, we need to handle that at this level.
-      if (EMT->hasParameterizedExistential()) {
+      if (EMT->getExistentialLayout().needsExtendedShape(AllowInverses)) {
         auto referent = SymbolicReferent::forExtendedExistentialTypeShape(EMT);
         if (canSymbolicReference(referent)) {
           appendSymbolicExtendedExistentialType(referent, EMT, sig, forDecl);
@@ -1616,7 +1641,7 @@ void ASTMangler::appendType(Type type, GenericSignature sig,
       }
 
       if (EMT->getInstanceType()->isExistentialType() &&
-          EMT->hasParameterizedExistential())
+          EMT->getExistentialLayout().needsExtendedShape(AllowInverses))
         appendConstrainedExistential(EMT->getInstanceType(), sig, forDecl);
       else
         appendType(EMT->getInstanceType(), sig, forDecl);
@@ -1672,8 +1697,7 @@ void ASTMangler::appendType(Type type, GenericSignature sig,
           return appendType(strippedTy, sig, forDecl);
       }
 
-      if (PCT->hasParameterizedExistential()
-          || (PCT->hasInverse() && AllowInverses))
+      if (PCT->getExistentialLayout().needsExtendedShape(AllowInverses))
         return appendConstrainedExistential(PCT, sig, forDecl);
 
       // We mangle ProtocolType and ProtocolCompositionType using the
@@ -1687,7 +1711,8 @@ void ASTMangler::appendType(Type type, GenericSignature sig,
 
     case TypeKind::Existential: {
       auto *ET = cast<ExistentialType>(tybase);
-      if (ET->hasParameterizedExistential()) {
+
+      if (ET->getExistentialLayout().needsExtendedShape(AllowInverses)) {
         auto referent = SymbolicReferent::forExtendedExistentialTypeShape(ET);
         if (canSymbolicReference(referent)) {
           appendSymbolicExtendedExistentialType(referent, ET, sig, forDecl);
@@ -1697,6 +1722,7 @@ void ASTMangler::appendType(Type type, GenericSignature sig,
         return appendConstrainedExistential(ET->getConstraintType(), sig,
                                             forDecl);
       }
+
       return appendType(ET->getConstraintType(), sig, forDecl);
     }
 
@@ -1749,9 +1775,10 @@ void ASTMangler::appendType(Type type, GenericSignature sig,
     case TypeKind::PackArchetype:
     case TypeKind::ElementArchetype:
     case TypeKind::ExistentialArchetype:
-      llvm::errs() << "Cannot mangle free-standing archetype: ";
-      tybase->dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Cannot mangle free-standing archetype: ";
+        tybase->dump(out);
+      });
 
     case TypeKind::OpaqueTypeArchetype: {
       auto opaqueType = cast<OpaqueTypeArchetypeType>(tybase);
@@ -1941,7 +1968,11 @@ void ASTMangler::appendFlatGenericArgs(SubstitutionMap subs,
   for (auto replacement : subs.getReplacementTypes()) {
     if (replacement->hasArchetype())
       replacement = replacement->mapTypeOutOfContext();
-    appendType(replacement, sig, forDecl);
+    if (DWARFMangling) {
+      appendType(replacement, sig, forDecl);
+    } else {
+      appendType(replacement->getCanonicalType(), sig, forDecl);
+    }
   }
 }
 
@@ -2254,6 +2285,10 @@ static char getResultConvention(ResultConvention conv) {
     case ResultConvention::UnownedInnerPointer: return 'u';
     case ResultConvention::Autoreleased: return 'a';
     case ResultConvention::Pack: return 'k';
+    case ResultConvention::GuaranteedAddress:
+      return 'g';
+    case ResultConvention::Guaranteed:
+      return 'G';
   }
   llvm_unreachable("bad result convention");
 }
@@ -2404,6 +2439,10 @@ void ASTMangler::appendImplFunctionType(SILFunctionType *fn,
     OpArgs.push_back(getParamConvention(param.getConvention()));
     if (param.hasOption(SILParameterInfo::Sending))
       OpArgs.push_back('T');
+    if (param.hasOption(SILParameterInfo::Isolated))
+      OpArgs.push_back('I');
+    if (param.hasOption(SILParameterInfo::ImplicitLeading))
+      OpArgs.push_back('L');
     if (auto diffKind = getParamDifferentiability(param.getOptions()))
       OpArgs.push_back(*diffKind);
     appendType(param.getInterfaceType(), sig, forDecl);
@@ -2515,6 +2554,14 @@ ASTMangler::getSpecialManglingContext(const ValueDecl *decl,
   if (auto file = dyn_cast<FileUnit>(decl->getDeclContext())) {
     if (file->getKind() == FileUnitKind::ClangModule ||
         file->getKind() == FileUnitKind::DWARFModule) {
+
+      // Use ClangImporterContext for compatibility aliases to avoid conflicting
+      // with the mangled name of the actual declaration.
+      if (auto *aliasDecl = dyn_cast<TypeAliasDecl>(decl)) {
+        if (aliasDecl->isCompatibilityAlias())
+          return ASTMangler::ClangImporterContext;
+      }
+
       if (decl->getClangDecl())
         return ASTMangler::ObjCContext;
       return ASTMangler::ClangImporterContext;
@@ -2542,6 +2589,8 @@ ASTMangler::getSpecialManglingContext(const ValueDecl *decl,
         hasNameForLinkage = !clangDecl->getDeclName().isEmpty();
       if (hasNameForLinkage) {
         auto *clangDC = clangDecl->getDeclContext();
+        while (isa<clang::LinkageSpecDecl>(clangDC))
+          clangDC = clangDC->getParent();
         // In C, "nested" structs, unions, enums, etc. will become siblings:
         //   struct Foo { struct Bar { }; }; -> struct Foo { }; struct Bar { };
         // Whereas in C++, nested records will actually be nested. So if this is
@@ -3000,7 +3049,7 @@ void ASTMangler::appendContextualInverses(const GenericTypeDecl *contextDecl,
   // that we're extending.
 
   // There are no generic parameters in this extension itself.
-  parts.params = std::nullopt;
+  parts.params = {};
 
   // The depth of parameters for this extension is +1 of the extended signature.
   parts.initialParamDepth = sig.getNextDepth();
@@ -3041,9 +3090,9 @@ void ASTMangler::appendExtension(const ExtensionDecl* ext,
   // "extension is to a protocol" would no longer be a reason to use the
   // extension mangling, because an extension method implementation could be
   // resiliently moved into the original protocol itself.
-  if (ext->isInSameDefiningModule() // case 1
-        && !sigParts.hasRequirements() // case 2
-        && !ext->getDeclaredInterfaceType()->isExistentialType()) { // case 3
+  if (ext->isInSameDefiningModule(RespectOriginallyDefinedIn)     // case 1
+      && !sigParts.hasRequirements()                              // case 2
+      && !ext->getDeclaredInterfaceType()->isExistentialType()) { // case 3
     // skip extension mangling
     return appendAnyGenericType(decl);
   }
@@ -3073,7 +3122,7 @@ void ASTMangler::appendAnyGenericType(const GenericTypeDecl *decl,
 
   auto *nominal = dyn_cast<NominalTypeDecl>(decl);
 
-  if (nominal && isa<BuiltinTupleDecl>(nominal))
+  if (isa_and_nonnull<BuiltinTupleDecl>(nominal))
     return appendOperator("BT");
 
   // Check for certain standard types.
@@ -3108,6 +3157,13 @@ void ASTMangler::appendAnyGenericType(const GenericTypeDecl *decl,
   // Always use Clang names for imported Clang declarations, unless they don't
   // have one.
   auto tryAppendClangName = [this, decl]() -> bool {
+    // We use the Swift name rather than the Clang name for compatibility
+    // aliases since they are ClangImporterContext entities.
+    if (auto *aliasDecl = dyn_cast<TypeAliasDecl>(decl)) {
+      if (aliasDecl->isCompatibilityAlias())
+        return false;
+    }
+
     auto *nominal = dyn_cast<NominalTypeDecl>(decl);
     auto namedDecl = getClangDeclForMangling(decl);
     if (!namedDecl) {
@@ -3125,6 +3181,12 @@ void ASTMangler::appendAnyGenericType(const GenericTypeDecl *decl,
       return false;
     }
 
+    // Mangle `Foo` from `namespace Bar { class Foo; } using Bar::Foo;` the same
+    // way as if we spelled `Bar.Foo` explicitly.
+    if (const auto *usingShadowDecl =
+            dyn_cast<clang::UsingShadowDecl>(namedDecl))
+      namedDecl = usingShadowDecl->getTargetDecl();
+
     // Mangle ObjC classes using their runtime names.
     auto interface = dyn_cast<clang::ObjCInterfaceDecl>(namedDecl);
     auto protocol = dyn_cast<clang::ObjCProtocolDecl>(namedDecl);
@@ -3365,7 +3427,7 @@ void ASTMangler::appendFunctionSignature(AnyFunctionType *fn,
       appendOperator("YA");
     break;
 
-  case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+  case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
     appendOperator("YC");
     break;
   }
@@ -3592,7 +3654,7 @@ bool ASTMangler::GenericSignatureParts::hasRequirements() const {
 }
 
 void ASTMangler::GenericSignatureParts::clear() {
-  params = std::nullopt;
+  params = {};
   requirements.clear();
   inverses.clear();
   initialParamDepth = 0;
@@ -4082,6 +4144,14 @@ void ASTMangler::appendBackingInitializerEntity(const VarDecl *var) {
   appendOperator("fP");
 }
 
+void ASTMangler::appendPropertyWrappedFieldInitAccessorEntity(
+    const VarDecl *var) {
+  llvm::SaveAndRestore X(AllowInverses, inversesAllowed(var));
+  BaseEntitySignature base(var);
+  appendEntity(var, base, "vp", var->isStatic());
+  appendOperator("fF");
+}
+
 void ASTMangler::appendInitFromProjectedValueEntity(const VarDecl *var) {
   llvm::SaveAndRestore X(AllowInverses, inversesAllowed(var));
   BaseEntitySignature base(var);
@@ -4461,8 +4531,7 @@ static unsigned conformanceRequirementIndex(
     ++result;
   }
 
-  llvm::errs() <<"Conformance access path step is missing from requirements";
-  abort();
+  ABORT("Conformance access path step is missing from requirements");
 }
 
 void ASTMangler::appendDependentProtocolConformance(
@@ -4566,9 +4635,10 @@ void ASTMangler::appendAnyProtocolConformance(
   } else if (conformance.isPack()) {
     appendPackProtocolConformance(conformance.getPack(), genericSig);
   } else {
-    llvm::errs() << "Bad conformance in mangler: ";
-    conformance.dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Bad conformance in mangler: ";
+      conformance.dump(out);
+    });
   }
 }
 
@@ -4909,7 +4979,7 @@ void ASTMangler::appendMacroExpansionContext(
       discriminator = expr->getDiscriminator();
       outerExpansionDC = expr->getDeclContext();
     } else {
-      auto decl = cast<MacroExpansionDecl>(parent.get<Decl *>());
+      auto decl = cast<MacroExpansionDecl>(cast<Decl *>(parent));
       outerExpansionLoc = decl->getLoc();
       baseName = decl->getMacroName().getBaseName();
       discriminator = decl->getDiscriminator();
@@ -4924,8 +4994,8 @@ void ASTMangler::appendMacroExpansionContext(
     case GeneratedSourceInfo::Name##MacroExpansion:
 #include "swift/Basic/MacroRoles.def"
   {
-    auto decl = ASTNode::getFromOpaqueValue(generatedSourceInfo->astNode)
-      .get<Decl *>();
+    auto decl =
+        cast<Decl *>(ASTNode::getFromOpaqueValue(generatedSourceInfo->astNode));
     auto attr = generatedSourceInfo->attachedMacroCustomAttr;
     outerExpansionLoc = decl->getLoc();
     outerExpansionDC = decl->getDeclContext();
@@ -5089,17 +5159,34 @@ namespace {
 /// Stores either a declaration or its enclosing context, for use in mangling
 /// of macro expansion contexts.
 struct DeclOrEnclosingContext: llvm::PointerUnion<const Decl *, const DeclContext *> {
+  using Base = llvm::PointerUnion<const Decl *, const DeclContext *>;
   using PointerUnion::PointerUnion;
 
-  const DeclContext *getEnclosingContext() const {
-    if (auto decl = dyn_cast<const Decl *>()) {
-      return decl->getDeclContext();
-    }
+  const DeclContext *getEnclosingContext() const;
+};
+
+} // namespace
+
+namespace llvm {
+
+using ::DeclOrEnclosingContext;
 
-    return get<const DeclContext *>();
+/// `isa`, `dyn_cast`, `cast` for `DeclOrEnclosingContext`.
+template <typename To>
+struct CastInfo<To, DeclOrEnclosingContext>
+    : CastInfo<To, DeclOrEnclosingContext::Base> {};
+template <typename To>
+struct CastInfo<To, const DeclOrEnclosingContext>
+    : CastInfo<To, const DeclOrEnclosingContext::Base> {};
+
+} // end namespace llvm
+
+const DeclContext *DeclOrEnclosingContext::getEnclosingContext() const {
+  if (auto decl = dyn_cast<const Decl *>()) {
+    return decl->getDeclContext();
   }
-};
 
+  return cast<const DeclContext *>(*this);
 }
 
 /// Given a declaration, find the declaration or enclosing context that is
@@ -5158,13 +5245,15 @@ std::string ASTMangler::mangleAttachedMacroExpansion(
 
     // If we needed a local discriminator, stuff that into the name itself.
     // This is hack, but these names aren't stable anyway.
+    bool skipLocalDiscriminator = false;
     if (auto discriminator = precheckedMangleContext.second) {
+      skipLocalDiscriminator = true;
       name = encodeLocalPrecheckedDiscriminator(
           decl->getASTContext(), name, *discriminator);
     }
 
     if (auto valueDecl = dyn_cast<ValueDecl>(decl))
-      appendDeclName(valueDecl, name);
+      appendDeclName(valueDecl, name, skipLocalDiscriminator);
     else if (!name.empty())
       appendIdentifier(name.str());
     else
@@ -5266,15 +5355,11 @@ static void extractExistentialInverseRequirements(
 
   auto &ctx = PCT->getASTContext();
 
-  // Form a parameter referring to the existential's Self.
-  auto existentialSelf =
-      GenericTypeParamType::getType(/*depth=*/0, /*index=*/0, ctx);
-
   for (auto ip : PCT->getInverses()) {
     auto *proto = ctx.getProtocol(getKnownProtocolKind(ip));
     assert(proto);
     ASSERT(!getABIDecl(proto) && "can't use @abi on inverse protocols");
-    inverses.push_back({existentialSelf, proto, SourceLoc()});
+    inverses.push_back({ctx.TheSelfType, proto, SourceLoc()});
   }
 }
 
@@ -5421,6 +5506,7 @@ ASTMangler::BaseEntitySignature::BaseEntitySignature(const Decl *decl)
     case DeclKind::PrefixOperator:
     case DeclKind::PostfixOperator:
     case DeclKind::MacroExpansion:
+    case DeclKind::Using:
       break;
     };
   }
diff --git a/lib/AST/ASTNode.cpp b/lib/AST/ASTNode.cpp
index f19b2117d1220..4ac48835e2632 100644
--- a/lib/AST/ASTNode.cpp
+++ b/lib/AST/ASTNode.cpp
@@ -60,9 +60,9 @@ DeclContext *ASTNode::getAsDeclContext() const {
   if (auto *E = this->dyn_cast<Expr*>()) {
     if (isa<AbstractClosureExpr>(E))
       return static_cast<AbstractClosureExpr*>(E);
-  } else if (is<Stmt*>()) {
+  } else if (isa<Stmt *>(*this)) {
     return nullptr;
-  } else if (auto *D = this->dyn_cast<Decl*>()) {
+  } else if (auto *D = this->dyn_cast<Decl *>()) {
     if (isa<DeclContext>(D))
       return cast<DeclContext>(D);
   } else if (getOpaqueValue())
@@ -79,11 +79,11 @@ bool ASTNode::isImplicit() const {
     return D->isImplicit();
   if (const auto *P = this->dyn_cast<Pattern*>())
     return P->isImplicit();
-  if (this->is<TypeRepr *>())
+  if (isa<TypeRepr *>(*this))
     return false;
-  if (this->is<StmtConditionElement *>())
+  if (isa<StmtConditionElement *>(*this))
     return false;
-  if (this->is<CaseLabelItem *>())
+  if (isa<CaseLabelItem *>(*this))
     return false;
   llvm_unreachable("unsupported AST node");
 }
@@ -124,9 +124,9 @@ void ASTNode::dump(raw_ostream &OS, unsigned Indent) const {
     P->dump(OS, Indent);
   else if (auto T = dyn_cast<TypeRepr*>())
     T->print(OS);
-  else if (is<StmtConditionElement *>())
+  else if (isa<StmtConditionElement *>(*this))
     OS.indent(Indent) << "(statement condition)";
-  else if (is<CaseLabelItem *>()) {
+  else if (isa<CaseLabelItem *>(*this)) {
     OS.indent(Indent) << "(case label item)";
   } else
     llvm_unreachable("unsupported AST node");
@@ -146,14 +146,40 @@ StringRef swift::getTokenText(tok kind) {
   }
 }
 
-#define FUNC(T)                                                               \
-bool ASTNode::is##T(T##Kind Kind) const {                                     \
-  if (!is<T*>())                                                              \
-    return false;                                                             \
-  return get<T*>()->getKind() == Kind;                                        \
-}
+#define FUNC(T)                                                                \
+  bool ASTNode::is##T(T##Kind Kind) const {                                    \
+    if (!isa<T *>(*this))                                                      \
+      return false;                                                            \
+    return cast<T *>(*this)->getKind() == Kind;                                \
+  }
 FUNC(Stmt)
 FUNC(Expr)
 FUNC(Decl)
 FUNC(Pattern)
 #undef FUNC
+
+SourceRange swift::getUnexpandedMacroRange(const SourceManager &SM,
+                                           SourceRange range) {
+  unsigned bufferID = SM.findBufferContainingLoc(range.Start);
+  SourceRange outerRange;
+  while (const auto *info = SM.getGeneratedSourceInfo(bufferID)) {
+    switch (info->kind) {
+#define MACRO_ROLE(Name, Description)                                          \
+  case GeneratedSourceInfo::Name##MacroExpansion:
+#include "swift/Basic/MacroRoles.def"
+      if (auto *customAttr = info->attachedMacroCustomAttr)
+        outerRange = customAttr->getRange();
+      else
+        outerRange =
+            ASTNode::getFromOpaqueValue(info->astNode).getSourceRange();
+      bufferID = SM.findBufferContainingLoc(outerRange.Start);
+      continue;
+    case GeneratedSourceInfo::ReplacedFunctionBody:
+    case GeneratedSourceInfo::PrettyPrinted:
+    case GeneratedSourceInfo::DefaultArgument:
+    case GeneratedSourceInfo::AttributeFromClang:
+      return SourceRange();
+    }
+  }
+  return outerRange;
+}
diff --git a/lib/AST/ASTPrinter.cpp b/lib/AST/ASTPrinter.cpp
index 765b5d7b498db..672ece35e33f2 100644
--- a/lib/AST/ASTPrinter.cpp
+++ b/lib/AST/ASTPrinter.cpp
@@ -20,6 +20,8 @@
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/ASTVisitor.h"
 #include "swift/AST/Attr.h"
+#include "swift/AST/AvailabilityConstraint.h"
+#include "swift/AST/AvailabilityContext.h"
 #include "swift/AST/Builtins.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/Comment.h"
@@ -103,6 +105,13 @@ void PrintOptions::initForSynthesizedExtension(TypeOrExtensionDecl D) {
   TransformContext = TypeTransformContext(D);
 }
 
+void PrintOptions::initForSynthesizedExtensionInScope(TypeOrExtensionDecl D,
+                                                      OverrideScope &scope) const {
+  assert(this == &scope.Options);
+  OVERRIDE_PRINT_OPTION_UNCONDITIONAL(scope, TransformContext,
+                                      TypeTransformContext(D));
+}
+
 void PrintOptions::clearSynthesizedExtension() {
   TransformContext.reset();
 }
@@ -148,7 +157,7 @@ static bool isPackage(Type ty) {
 
 static bool isPrespecilizationDeclWithTarget(const ValueDecl *vd) {
   // Add exported prespecialized symbols.
-  for (auto *attr : vd->getAttrs().getAttributes<SpecializeAttr>()) {
+  for (auto *attr : vd->getAttrs().getAttributes<AbstractSpecializeAttr>()) {
     if (!attr->isExported())
       continue;
     if (attr->getTargetFunctionDecl(vd))
@@ -182,6 +191,47 @@ static bool shouldPrintAllSemanticDetails(const PrintOptions &options) {
   return false;
 }
 
+static bool shouldSkipDeclInPublicInterface(const Decl *D) {
+  // @_spi should be skipped in the public interface.
+  if (D->isSPI())
+    return true;
+
+  // Decls that are unavailable at runtime in an availability domain that has
+  // been @_spiOnly imported should be hidden from the public interface of
+  // a -library-level=api module.
+  auto &ctx = D->getDeclContext()->getASTContext();
+  if (ctx.LangOpts.LibraryLevel != LibraryLevel::API)
+    return false;
+
+  auto *SF = D->getDeclContext()->getParentSourceFile();
+  if (!SF)
+    return false;
+
+  auto constraints = getAvailabilityConstraintsForDecl(
+      D, AvailabilityContext::forDeploymentTarget(ctx));
+  llvm::SmallVector<AvailabilityDomain, 4> unavailableDomains;
+  getRuntimeUnavailableDomains(constraints, unavailableDomains, ctx);
+
+  for (auto domain : unavailableDomains) {
+    if (auto *domainDecl = domain.getDecl()) {
+      if (SF->getRestrictedImportKind(domainDecl->getModuleContext()) ==
+          RestrictedImportKind::SPIOnly)
+        return true;
+    }
+  }
+
+  return false;
+}
+
+/// Get the non-recursive printing options that should be applied when
+/// printing the type of a value decl.
+static NonRecursivePrintOptions getNonRecursiveOptions(const ValueDecl *D) {
+  NonRecursivePrintOptions options;
+  if (D->isImplicitlyUnwrappedOptional())
+    options |= NonRecursivePrintOption::ImplicitlyUnwrappedOptional;
+  return options;
+}
+
 bool PrintOptions::excludeAttr(const DeclAttribute *DA) const {
   if (excludeAttrKind(DA->getKind())) {
     return true;
@@ -197,9 +247,9 @@ bool PrintOptions::excludeAttr(const DeclAttribute *DA) const {
 /// Forces printing types with the `some` keyword, instead of the full stable
 /// reference.
 struct PrintWithOpaqueResultTypeKeywordRAII {
-  PrintWithOpaqueResultTypeKeywordRAII(PrintOptions &Options)
-      : Options(Options) {
-    SavedMode = Options.OpaqueReturnTypePrinting;
+  PrintWithOpaqueResultTypeKeywordRAII(const PrintOptions &options)
+      : Options(const_cast<PrintOptions&>(options)) {
+    SavedMode = options.OpaqueReturnTypePrinting;
     Options.OpaqueReturnTypePrinting =
         PrintOptions::OpaqueReturnTypePrintingMode::WithOpaqueKeyword;
   }
@@ -277,8 +327,7 @@ PrintOptions PrintOptions::printSwiftInterfaceFile(ModuleDecl *ModuleToPrint,
       if (D->getAttrs().hasAttribute<ImplementationOnlyAttr>())
         return false;
 
-      // Skip SPI decls if `PrintSPIs`.
-      if (options.printPublicInterface() && D->isSPI())
+      if (options.printPublicInterface() && shouldSkipDeclInPublicInterface(D))
         return false;
 
       if (auto *VD = dyn_cast<ValueDecl>(D)) {
@@ -304,6 +353,13 @@ PrintOptions PrintOptions::printSwiftInterfaceFile(ModuleDecl *ModuleToPrint,
         }
       }
 
+      // Skip @c @implementation functions along with the attribute.
+      if (auto AFD = dyn_cast<AbstractFunctionDecl>(D)) {
+        if (options.excludeAttrKind(DeclAttrKind::ObjCImplementation) &&
+            AFD->isObjCImplementation() && AFD->getCDeclKind())
+          return false;
+      }
+
       // Skip extensions that extend things we wouldn't print.
       if (auto *ED = dyn_cast<ExtensionDecl>(D)) {
         if (!shouldPrint(ED->getExtendedNominal(), options))
@@ -376,21 +432,24 @@ PrintOptions PrintOptions::printSwiftInterfaceFile(ModuleDecl *ModuleToPrint,
         if (auto *element = ECD->getFirstElement()) {
           // Enum elements are usually not printed, so we have to override the
           // print option controlling that.
-          PrintOptions optionsCopy = options;
-          optionsCopy.ExplodeEnumCaseDecls = true;
-          if (!shouldPrint(element, optionsCopy))
+          PrintOptions::OverrideScope scope(options);
+          OVERRIDE_PRINT_OPTION(scope, ExplodeEnumCaseDecls, true);
+          if (!shouldPrint(element, options))
             return false;
         }
       }
 
+      // The `using` declarations are private to the file at the moment
+      // and shouldn't appear in swift interfaces.
+      if (isa<UsingDecl>(D))
+        return false;
+
       return ShouldPrintChecker::shouldPrint(D, options);
     }
   };
   result.CurrentPrintabilityChecker =
       std::make_shared<ShouldPrintForModuleInterface>();
 
-  // FIXME: We don't really need 'public' on everything; we could just change
-  // the default to 'public' and mark the 'internal' things.
   result.PrintAccess = true;
 
   result.ExcludeAttrList = {
@@ -417,7 +476,7 @@ TypeTransformContext::TypeTransformContext(TypeOrExtensionDecl D)
   if (auto NTD = Decl.Decl.dyn_cast<NominalTypeDecl *>())
     BaseType = NTD->getDeclaredTypeInContext().getPointer();
   else {
-    auto *ED = Decl.Decl.get<ExtensionDecl *>();
+    auto *ED = cast<ExtensionDecl *>(Decl.Decl);
     BaseType = ED->getDeclaredTypeInContext().getPointer();
   }
 }
@@ -666,7 +725,7 @@ namespace {
 /// AST pretty-printer.
 class PrintAST : public ASTVisitor<PrintAST> {
   ASTPrinter &Printer;
-  PrintOptions Options;
+  const PrintOptions &Options;
   unsigned IndentLevel = 0;
   Decl *Current = nullptr;
   Type CurrentType;
@@ -866,14 +925,8 @@ class PrintAST : public ASTVisitor<PrintAST> {
       return;
     if (D->getDeclContext()->isLocalContext())
       return;
-    
-    if (Options.SuppressIsolatedDeinit &&
-        D->getFormalAccess() == AccessLevel::Open &&
-        usesFeatureIsolatedDeinit(D)) {
-      printAccess(AccessLevel::Public);
-    } else {
-      printAccess(D->getFormalAccess());
-    }
+
+    printAccess(D->getFormalAccess());
     bool shouldSkipSetterAccess =
         llvm::is_contained(Options.ExcludeAttrList, DeclAttrKind::SetterAccess);
 
@@ -886,26 +939,24 @@ class PrintAST : public ASTVisitor<PrintAST> {
     }
   }
 
-  void printTypeWithOptions(Type T, const PrintOptions &options) {
-    if (options.TransformContext) {
+  void printType(Type T,
+                 NonRecursivePrintOptions outermostOptions = std::nullopt) {
+    if (Options.TransformContext) {
       // FIXME: it's not clear exactly what we want to keep from the existing
       // options, and what we want to discard.
       PrintOptions FreshOptions;
-      FreshOptions.ExcludeAttrList = options.ExcludeAttrList;
-      FreshOptions.ExclusiveAttrList = options.ExclusiveAttrList;
-      FreshOptions.PrintOptionalAsImplicitlyUnwrapped = options.PrintOptionalAsImplicitlyUnwrapped;
-      FreshOptions.TransformContext = options.TransformContext;
-      FreshOptions.CurrentModule = options.CurrentModule;
-      FreshOptions.FullyQualifiedTypesIfAmbiguous = options.FullyQualifiedTypesIfAmbiguous;
-      T.print(Printer, FreshOptions);
+      FreshOptions.ExcludeAttrList = Options.ExcludeAttrList;
+      FreshOptions.ExclusiveAttrList = Options.ExclusiveAttrList;
+      FreshOptions.TransformContext = Options.TransformContext;
+      FreshOptions.CurrentModule = Options.CurrentModule;
+      FreshOptions.FullyQualifiedTypesIfAmbiguous = Options.FullyQualifiedTypesIfAmbiguous;
+      T.print(Printer, FreshOptions, outermostOptions);
       return;
     }
 
-    T.print(Printer, options);
+    T.print(Printer, Options, outermostOptions);
   }
 
-  void printType(Type T) { printTypeWithOptions(T, Options); }
-
   Type getTransformedType(Type T) {
     if (CurrentType && Current && CurrentType->mayHaveMembers()) {
       SubstitutionMap subMap;
@@ -931,54 +982,46 @@ class PrintAST : public ASTVisitor<PrintAST> {
     return T;
   }
 
-  void printTransformedTypeWithOptions(Type T, PrintOptions options) {
+  void printTransformedType(Type T,
+                            NonRecursivePrintOptions outermostOptions = std::nullopt) {
     T = getTransformedType(T);
 
+    PrintOptions::OverrideScope scope(Options);
     if (CurrentType && Current && CurrentType->mayHaveMembers())
-      options.TransformContext = TypeTransformContext(CurrentType);
+      OVERRIDE_PRINT_OPTION_UNCONDITIONAL(scope, TransformContext,
+                                          TypeTransformContext(CurrentType));
 
-    printTypeWithOptions(T, options);
+    printType(T, outermostOptions);
   }
 
-  void printTransformedType(Type T) {
-    printTransformedTypeWithOptions(T, Options);
-  }
-
-  void printTypeLocWithOptions(const TypeLoc &TL, const PrintOptions &options,
-      std::optional<llvm::function_ref<void()>> printBeforeType = std::nullopt) {
+  void printTypeLoc(const TypeLoc &TL,
+        NonRecursivePrintOptions outermostOptions = std::nullopt,
+        std::optional<llvm::function_ref<void()>> printBeforeType = std::nullopt) {
     if (CurrentType && TL.getType()) {
       if (printBeforeType) (*printBeforeType)();
-      printTransformedTypeWithOptions(TL.getType(), options);
+      printTransformedType(TL.getType(), outermostOptions);
       return;
     }
 
     // Print a TypeRepr if instructed to do so by options, or if the type
     // is null.
-    if (willUseTypeReprPrinting(TL, CurrentType, options)) {
+    if (willUseTypeReprPrinting(TL, CurrentType, Options)) {
       if (auto repr = TL.getTypeRepr())
-        repr->print(Printer, options);
+        repr->print(Printer, Options, outermostOptions);
       return;
     }
 
     if (printBeforeType) (*printBeforeType)();
-    TL.getType().print(Printer, options);
+    TL.getType().print(Printer, Options, outermostOptions);
   }
 
-  void printTypeLoc(const TypeLoc &TL) { printTypeLocWithOptions(TL, Options); }
-
   /// Print a TypeLoc.  If we decide to print based on the type, rather than
   /// based on the TypeRepr, call the given function before printing the type;
   /// this is useful if there are attributes in the TypeRepr which don't end
   /// up being part of the type, such as `@unchecked` in inheritance clauses.
   void printTypeLoc(const TypeLoc &TL,
                     llvm::function_ref<void()> printBeforeType) {
-    printTypeLocWithOptions(TL, Options, printBeforeType);
-  }
-
-  void printTypeLocForImplicitlyUnwrappedOptional(TypeLoc TL, bool IUO) {
-    PrintOptions options = Options;
-    options.PrintOptionalAsImplicitlyUnwrapped = IUO;
-    printTypeLocWithOptions(TL, options);
+    printTypeLoc(TL, /*non-recursive options*/std::nullopt, printBeforeType);
   }
 
   void printContextIfNeeded(const Decl *decl) {
@@ -1067,6 +1110,8 @@ class PrintAST : public ASTVisitor<PrintAST> {
   void printRequirement(const InverseRequirement &inverse,
                         bool forInherited);
 
+  void printArgumentList(ArgumentList *args, bool forSubscript = false);
+
 private:
   bool shouldPrint(const Decl *D, bool Notify = false);
   bool shouldPrintPattern(const Pattern *P);
@@ -1090,19 +1135,20 @@ class PrintAST : public ASTVisitor<PrintAST> {
   bool printASTNodes(const ArrayRef<ASTNode> &Elements, bool NeedIndent = true);
 
   void printOneParameter(const ParamDecl *param, ParameterTypeFlags paramFlags,
-                         bool ArgNameIsAPIByDefault);
+                         bool ArgNameIsAPIByDefault, bool isEnumElement);
 
   void printParameterList(ParameterList *PL,
                           ArrayRef<AnyFunctionType::Param> params,
-                          bool isAPINameByDefault);
+                          bool isAPINameByDefault,
+                          bool isEnumElement);
 
   /// Print the function parameters in curried or selector style,
   /// to match the original function declaration.
   void printFunctionParameters(AbstractFunctionDecl *AFD);
 
   void printArgument(const Argument &arg);
-  
-  void printArgumentList(ArgumentList *args, bool forSubscript = false);
+
+  void printAvailabilitySpec(AvailabilitySpec *spec);
 
   void printStmtCondition(StmtCondition stmt);
 
@@ -1284,12 +1330,18 @@ void PrintAST::printAttributes(const Decl *D) {
   // for each decl They cannot be shared across different decls.
   assert(Options.ExcludeCustomAttrList.empty());
 
+  PrintOptions::OverrideScope scope(Options);
+  scope.addFinalizer([originalExcludeAttrCount](PrintOptions &options) {
+    options.ExcludeAttrList.resize(originalExcludeAttrCount);
+    options.ExcludeCustomAttrList.clear();
+  });
+
   // If there is an `@abi` attr, we need to print it first so that it isn't
   // affected by subsequent mutation of `Options.ExcludeAttrList`.
   if (auto abiAttr = attrs.getAttribute<ABIAttr>()) {
     if (Options.PrintImplicitAttrs && !Options.excludeAttr(abiAttr)) {
       abiAttr->print(Printer, Options, D);
-      Options.ExcludeAttrList.push_back(DeclAttrKind::ABI);
+      scope.Options.ExcludeAttrList.push_back(DeclAttrKind::ABI);
     }
   }
 
@@ -1310,7 +1362,7 @@ void PrintAST::printAttributes(const Decl *D) {
       Printer.printEscapedStringLiteral(
           "this compiler cannot match the ABI specified by the @abi attribute");
       Printer << ")\n";
-      Options.ExcludeAttrList.push_back(DeclAttrKind::Available);
+      scope.Options.ExcludeAttrList.push_back(DeclAttrKind::Available);
     }
   }
 
@@ -1319,7 +1371,7 @@ void PrintAST::printAttributes(const Decl *D) {
     // Don't print a redundant 'final' if we are printing a 'static' decl.
     if (D->getDeclContext()->getSelfClassDecl() &&
         getCorrectStaticSpelling(D) == StaticSpellingKind::KeywordStatic) {
-      Options.ExcludeAttrList.push_back(DeclAttrKind::Final);
+      scope.Options.ExcludeAttrList.push_back(DeclAttrKind::Final);
     }
 
     if (auto vd = dyn_cast<VarDecl>(D)) {
@@ -1328,7 +1380,7 @@ void PrintAST::printAttributes(const Decl *D) {
       // @objcImplementation extension (where final properties should appear
       // computed).
       if (vd->isInitExposedToClients() || vd->isResilient() || isInObjCImpl(vd))
-        Options.ExcludeAttrList.push_back(DeclAttrKind::HasInitialValue);
+        scope.Options.ExcludeAttrList.push_back(DeclAttrKind::HasInitialValue);
 
       if (!Options.PrintForSIL) {
         // Don't print @_hasStorage if the value is simply stored, or the
@@ -1336,7 +1388,7 @@ void PrintAST::printAttributes(const Decl *D) {
         if (vd->isResilient() || isInObjCImpl(vd) ||
             (vd->getImplInfo().isSimpleStored() &&
              !hasLessAccessibleSetter(vd)))
-          Options.ExcludeAttrList.push_back(DeclAttrKind::HasStorage);
+          scope.Options.ExcludeAttrList.push_back(DeclAttrKind::HasStorage);
       }
     }
 
@@ -1351,14 +1403,14 @@ void PrintAST::printAttributes(const Decl *D) {
                Printer << "(" << spiName << ") ";
              },
              [&] { Printer << ""; });
-      Options.ExcludeAttrList.push_back(DeclAttrKind::SPIAccessControl);
+      scope.Options.ExcludeAttrList.push_back(DeclAttrKind::SPIAccessControl);
     }
 
     // Don't print any contextual decl modifiers.
     // We will handle 'mutating' and 'nonmutating' separately.
     if (isa<AccessorDecl>(D)) {
 #define EXCLUDE_ATTR(Class)                                                    \
-  Options.ExcludeAttrList.push_back(DeclAttrKind::Class);
+      scope.Options.ExcludeAttrList.push_back(DeclAttrKind::Class);
 #define CONTEXTUAL_DECL_ATTR(X, Class, ...) EXCLUDE_ATTR(Class)
 #define CONTEXTUAL_SIMPLE_DECL_ATTR(X, Class, ...) EXCLUDE_ATTR(Class)
 #define CONTEXTUAL_DECL_ATTR_ALIAS(X, Class) EXCLUDE_ATTR(Class)
@@ -1393,32 +1445,33 @@ void PrintAST::printAttributes(const Decl *D) {
   if (auto ED = dyn_cast<ExtensionDecl>(D)) {
     if (ED->isObjCImplementation() &&
             Options.excludeAttrKind(DeclAttrKind::ObjCImplementation)) {
-      Options.ExcludeAttrList.push_back(DeclAttrKind::ObjC);
+      scope.Options.ExcludeAttrList.push_back(DeclAttrKind::ObjC);
     }
   }
 
   // We will handle ownership specifiers separately.
   if (isa<FuncDecl>(D)) {
-    Options.ExcludeAttrList.push_back(DeclAttrKind::Mutating);
-    Options.ExcludeAttrList.push_back(DeclAttrKind::NonMutating);
-    Options.ExcludeAttrList.push_back(DeclAttrKind::LegacyConsuming);
-    Options.ExcludeAttrList.push_back(DeclAttrKind::Consuming);
-    Options.ExcludeAttrList.push_back(DeclAttrKind::Borrowing);
-  }
-
-  if (isa<DestructorDecl>(D) && Options.SuppressIsolatedDeinit) {
-    Options.ExcludeAttrList.push_back(DeclAttrKind::Nonisolated);
-    Options.ExcludeAttrList.push_back(DeclAttrKind::Isolated);
-    if (auto globalActor = D->getGlobalActorAttr()) {
-      Options.ExcludeCustomAttrList.push_back(globalActor->first);
+    scope.Options.ExcludeAttrList.push_back(DeclAttrKind::Mutating);
+    scope.Options.ExcludeAttrList.push_back(DeclAttrKind::NonMutating);
+    scope.Options.ExcludeAttrList.push_back(DeclAttrKind::LegacyConsuming);
+    scope.Options.ExcludeAttrList.push_back(DeclAttrKind::Consuming);
+    scope.Options.ExcludeAttrList.push_back(DeclAttrKind::Borrowing);
+  }
+
+  // If we're printing a swiftinterface and the attached property wrappers don't
+  // have an external effect, skip them.
+  if (Options.IsForSwiftInterface) {
+    if (auto *PD = dyn_cast<ParamDecl>(D)) {
+      if (!PD->hasExternalPropertyWrapper() &&
+          PD->getDeclContext()->getResilienceExpansion() !=
+              ResilienceExpansion::Minimal) {
+        for (auto *attr : PD->getAttachedPropertyWrappers())
+          scope.Options.ExcludeCustomAttrList.push_back(attr);
+      }
     }
   }
-  
-  attrs.print(Printer, Options, D);
-
 
-  Options.ExcludeAttrList.resize(originalExcludeAttrCount);
-  Options.ExcludeCustomAttrList.clear();
+  attrs.print(Printer, Options, D);
 }
 
 void PrintAST::printTypedPattern(const TypedPattern *TP) {
@@ -1429,14 +1482,14 @@ void PrintAST::printTypedPattern(const TypedPattern *TP) {
 
   // Make sure to check if the underlying var decl is an implicitly unwrapped
   // optional.
-  bool isIUO = false;
+  NonRecursivePrintOptions outermostOptions;
   if (auto *named = dyn_cast<NamedPattern>(TP->getSubPattern()))
     if (auto decl = named->getDecl())
-      isIUO = decl->isImplicitlyUnwrappedOptional();
+      outermostOptions = getNonRecursiveOptions(decl);
 
   const auto TyLoc = TypeLoc(TP->getTypeRepr(),
                              TP->hasType() ? TP->getType() : Type());
-  printTypeLocForImplicitlyUnwrappedOptional(TyLoc, isIUO);
+  printTypeLoc(TyLoc, outermostOptions);
 }
 
 /// Determines if we are required to print the name of a property declaration,
@@ -1914,15 +1967,9 @@ void PrintAST::printSingleDepthOfGenericSignature(
     if (subMap.empty())
       return param;
 
-    return param.subst(
-      [&](SubstitutableType *type) -> Type {
-        if (cast<GenericTypeParamType>(type)->getDepth() < typeContextDepth)
-          return Type(type).subst(subMap);
-        return type;
-      },
-      [&](CanType depType, Type substType, ProtocolDecl *proto) {
-        return lookupConformance(substType, proto);
-      });
+    OuterSubstitutions replacer{subMap, typeContextDepth};
+    return param.subst(replacer, replacer,
+                       SubstFlags::PreservePackExpansionLevel);
   };
 
   /// Separate the explicit generic parameters from the implicit, opaque
@@ -2234,8 +2281,11 @@ bool isNonSendableExtension(const Decl *D) {
   if (!ED || !ED->isUnavailable())
     return false;
 
-  auto nonSendable =
-      ED->getExtendedNominal()->getAttrs().getEffectiveSendableAttr();
+  auto *NTD = ED->getExtendedNominal();
+  if (!NTD)
+    return false;
+
+  auto nonSendable = NTD->getAttrs().getEffectiveSendableAttr();
   if (!isa_and_nonnull<NonSendableAttr>(nonSendable))
     return false;
 
@@ -2624,6 +2674,8 @@ void PrintAST::printAccessors(const AbstractStorageDecl *ASD) {
       }
       AddAccessorToPrint(AccessorKind::Read2);
       break;
+    case ReadImplKind::Borrow:
+      AddAccessorToPrint(AccessorKind::Borrow);
     }
     switch (impl.getWriteImpl()) {
     case WriteImplKind::Immutable:
@@ -2658,6 +2710,9 @@ void PrintAST::printAccessors(const AbstractStorageDecl *ASD) {
       }
       AddAccessorToPrint(AccessorKind::Modify2);
       break;
+    case WriteImplKind::Mutate:
+      AddAccessorToPrint(AccessorKind::Mutate);
+      break;
     }
   }
 
@@ -2729,6 +2784,10 @@ static void addNamespaceMembers(Decl *decl,
     declOwner = declOwner->getTopLevelModule();
   auto Redecls = llvm::SmallVector<clang::NamespaceDecl *, 2>(namespaceDecl->redecls());
   std::stable_sort(Redecls.begin(), Redecls.end(), [&](clang::NamespaceDecl *LHS, clang::NamespaceDecl *RHS) {
+    // A namespace redeclaration will not have an owning Clang module if it is
+    // declared in a bridging header.
+    if (!LHS->getOwningModule() || !RHS->getOwningModule())
+      return (bool)LHS->getOwningModule() < (bool)RHS->getOwningModule();
     return LHS->getOwningModule()->Name < RHS->getOwningModule()->Name;
   });
   for (auto redecl : Redecls) {
@@ -2757,7 +2816,7 @@ static void addNamespaceMembers(Decl *decl,
             ctx.evaluator, ClangDirectLookupRequest({decl, redecl, name}), {});
 
         for (auto found : allResults) {
-          auto clangMember = found.get<clang::NamedDecl *>();
+          auto clangMember = cast<clang::NamedDecl *>(found);
           if (auto importedDecl =
                   ctx.getClangModuleLoader()->importDeclDirectly(clangMember)) {
             if (addedMembers.insert(importedDecl).second) {
@@ -3055,14 +3114,15 @@ void PrintAST::visitImportDecl(ImportDecl *decl) {
                    [&] { Printer << "."; });
 }
 
+void PrintAST::visitUsingDecl(UsingDecl *decl) {
+  Printer.printIntroducerKeyword("using", Options, " ");
+  Printer << decl->getSpecifierName();
+}
+
 void PrintAST::printExtendedTypeName(TypeLoc ExtendedTypeLoc) {
-  bool OldFullyQualifiedTypesIfAmbiguous =
-    Options.FullyQualifiedTypesIfAmbiguous;
-  Options.FullyQualifiedTypesIfAmbiguous =
-    Options.FullyQualifiedExtendedTypesIfAmbiguous;
-  SWIFT_DEFER {
-    Options.FullyQualifiedTypesIfAmbiguous = OldFullyQualifiedTypesIfAmbiguous;
-  };
+  PrintOptions::OverrideScope scope(Options);
+  OVERRIDE_PRINT_OPTION(scope, FullyQualifiedTypesIfAmbiguous,
+                        Options.FullyQualifiedExtendedTypesIfAmbiguous);
 
   // Strip off generic arguments, if any.
   auto Ty = ExtendedTypeLoc.getType()->getAnyNominal()->getDeclaredType();
@@ -3121,10 +3181,10 @@ void PrintAST::printSynthesizedExtensionImpl(Type ExtendedType,
       if (auto *NTD = Target->getExtendedNominal()) {
         // Update the current decl and type transform for Target rather than
         // ExtDecl.
-        PrintOptions Adjusted = Options;
-        Adjusted.initForSynthesizedExtension(NTD);
+        PrintOptions::OverrideScope scope(Options);
+        Options.initForSynthesizedExtensionInScope(NTD, scope);
+
         llvm::SaveAndRestore<Decl*> TempCurrent(Current, NTD);
-        llvm::SaveAndRestore<PrintOptions> TempOptions(Options, Adjusted);
         printRequirementsFrom(Target, IsFirst);
       }
     }
@@ -3218,30 +3278,10 @@ void PrintAST::printExtension(ExtensionDecl *decl) {
   }
 }
 
-static void suppressingFeatureIsolatedAny(PrintOptions &options,
-                                          llvm::function_ref<void()> action) {
-  llvm::SaveAndRestore<bool> scope(options.SuppressIsolatedAny, true);
-  action();
-}
-
-static void
-suppressingFeatureSendingArgsAndResults(PrintOptions &options,
-                                        llvm::function_ref<void()> action) {
-  llvm::SaveAndRestore<bool> scope(options.SuppressSendingArgsAndResults, true);
-  action();
-}
-
 static void
-suppressingFeatureBitwiseCopyable2(PrintOptions &options,
-                                   llvm::function_ref<void()> action) {
-  llvm::SaveAndRestore<bool> scope(options.SuppressBitwiseCopyable, true);
-  action();
-}
-
-static void
-suppressingFeatureIsolatedDeinit(PrintOptions &options,
-                                 llvm::function_ref<void()> action) {
-  llvm::SaveAndRestore<bool> scope(options.SuppressIsolatedDeinit, true);
+suppressingFeatureLifetimes(PrintOptions &options,
+                                     llvm::function_ref<void()> action) {
+  llvm::SaveAndRestore<bool> scope(options.SuppressLifetimes, true);
   action();
 }
 
@@ -3264,20 +3304,6 @@ struct ExcludeAttrRAII {
 };
 }
 
-static void
-suppressingFeatureMemorySafetyAttributes(PrintOptions &options,
-                                       llvm::function_ref<void()> action) {
-  ExcludeAttrRAII scope(options.ExcludeAttrList, DeclAttrKind::Unsafe);
-  ExcludeAttrRAII scope2(options.ExcludeAttrList, DeclAttrKind::Safe);
-  options.ExcludeAttrList.push_back(TypeAttrKind::Unsafe);
-  SWIFT_DEFER {
-    assert(options.ExcludeAttrList.back() == TypeAttrKind::Unsafe);
-    options.ExcludeAttrList.pop_back();
-  };
-
-  action();
-}
-
 static void
 suppressingFeatureCoroutineAccessors(PrintOptions &options,
                                      llvm::function_ref<void()> action) {
@@ -3286,8 +3312,8 @@ suppressingFeatureCoroutineAccessors(PrintOptions &options,
 }
 
 static void
-suppressingFeatureABIAttribute(PrintOptions &options,
-                               llvm::function_ref<void()> action) {
+suppressingFeatureABIAttributeSE0479(PrintOptions &options,
+                                     llvm::function_ref<void()> action) {
   llvm::SaveAndRestore<bool> scope1(options.PrintSyntheticSILGenName, true);
   ExcludeAttrRAII scope2(options.ExcludeAttrList, DeclAttrKind::ABI);
   action();
@@ -3302,24 +3328,27 @@ suppressingFeatureAddressableTypes(PrintOptions &options,
 }
 
 static void
-suppressingFeatureCustomAvailability(PrintOptions &options,
-                                     llvm::function_ref<void()> action) {
-  // FIXME: [availability] Save and restore a bit controlling whether
-  // @available attributes for custom domains are printed.
+suppressingFeatureNonexhaustiveAttribute(PrintOptions &options,
+                                         llvm::function_ref<void()> action) {
+  ExcludeAttrRAII scope(options.ExcludeAttrList, DeclAttrKind::Nonexhaustive);
   action();
 }
 
 static void
-suppressingFeatureExecutionAttribute(PrintOptions &options,
-                                    llvm::function_ref<void()> action) {
-  llvm::SaveAndRestore<bool> scope1(options.SuppressExecutionAttribute, true);
-  ExcludeAttrRAII scope2(options.ExcludeAttrList, DeclAttrKind::Execution);
+suppressingFeatureInlineAlways(PrintOptions &options,
+                               llvm::function_ref<void()> action) {
+  llvm::SaveAndRestore<bool> scope(options.SuppressInlineAlways, true);
   action();
 }
 
 /// Suppress the printing of a particular feature.
-static void suppressingFeature(PrintOptions &options, Feature feature,
+static void suppressingFeature(const PrintOptions &_options, Feature feature,
                                llvm::function_ref<void()> action) {
+  // Just as we do in OverrideScope, we assume that PrintOptions objects are
+  // always actually temporarily mutable.  We do this here to avoid needing
+  // a const_cast in each of the individual suppression functions above.
+  auto &options = const_cast<PrintOptions&>(_options);
+
   switch (feature) {
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
   case Feature::FeatureName:                                                   \
@@ -3351,7 +3380,7 @@ static void printCompatibilityCheckIf(ASTPrinter &printer, bool isElseIf,
     } else {
       first = false;
     }
-    printer << "$" << getFeatureName(feature);
+    printer << "$" << Feature(feature).getName();
   }
 
 #ifndef NDEBUG
@@ -3368,7 +3397,7 @@ static void printCompatibilityCheckIf(ASTPrinter &printer, bool isElseIf,
 /// Generate a #if ... #elseif ... #endif chain for the given
 /// suppressible feature checks.
 static void printWithSuppressibleFeatureChecks(ASTPrinter &printer,
-                                               PrintOptions &options,
+                                               const PrintOptions &options,
                                                bool firstInChain,
                                                bool includeCompilerCheck,
                             FeatureSet::SuppressibleGenerator &generator,
@@ -3423,7 +3452,7 @@ static void printWithSuppressibleFeatureChecks(ASTPrinter &printer,
 ///   #endif
 /// ```
 void swift::printWithCompatibilityFeatureChecks(ASTPrinter &printer,
-                                                PrintOptions &options,
+                                                const PrintOptions &options,
                                                 Decl *decl,
                                  llvm::function_ref<void()> printBody) {
   // A single accessor does not get a feature check,
@@ -3509,12 +3538,14 @@ void PrintAST::visitPatternBindingDecl(PatternBindingDecl *decl) {
   if (decl->isStatic())
     printStaticKeyword(decl->getCorrectStaticSpelling());
 
+  bool printAsVar = false;
   if (anyVar) {
-    Printer << (anyVar->isSettable(anyVar->getDeclContext()) ? "var " : "let ");
-  } else {
-    Printer << "let ";
+    printAsVar = (anyVar->isSettable(anyVar->getDeclContext()) ||
+                  isInObjCImpl(anyVar));
   }
 
+  Printer << (printAsVar ? "var " : "let ");
+
   bool isFirst = true;
   for (auto idx : range(decl->getNumPatternEntries())) {
     auto *pattern = decl->getPattern(idx);
@@ -3583,28 +3614,17 @@ void PrintAST::visitOpaqueTypeDecl(OpaqueTypeDecl *decl) {
 
 void PrintAST::visitTypeAliasDecl(TypeAliasDecl *decl) {
   auto name = decl->getName();
-  bool suppressingBitwiseCopyable =
-      Options.SuppressBitwiseCopyable &&
-      decl->getModuleContext()->isStdlibModule() &&
-      (decl->getNameStr() == "_BitwiseCopyable");
-  if (suppressingBitwiseCopyable) {
-    name = decl->getASTContext().getIdentifier("BitwiseCopyable");
-  }
   printDocumentationComment(decl);
   printAttributes(decl);
   printAccess(decl);
   Printer.printIntroducerKeyword("typealias", Options, " ");
   printContextIfNeeded(decl);
-  recordDeclLoc(decl,
-    [&]{
-      Printer.printName(name, getTypeMemberPrintNameContext(decl));
-    }, [&]{ // Signature
-      printGenericDeclGenericParams(decl);
-    });
-  if (suppressingBitwiseCopyable) {
-    Printer << " = Swift._BitwiseCopyable";
-    return;
-  }
+  recordDeclLoc(
+      decl,
+      [&] { Printer.printName(name, getTypeMemberPrintNameContext(decl)); },
+      [&] { // Signature
+        printGenericDeclGenericParams(decl);
+      });
   bool ShouldPrint = true;
   Type Ty = decl->getUnderlyingType();
 
@@ -3614,16 +3634,6 @@ void PrintAST::visitTypeAliasDecl(TypeAliasDecl *decl) {
 
   if (ShouldPrint) {
     Printer << " = ";
-    // FIXME: An inferred associated type witness type alias may reference
-    // an opaque type, but OpaqueTypeArchetypes are always canonicalized
-    // so lose type sugar for generic params. Bind the generic signature so
-    // we can map params back into the generic signature and print them
-    // correctly.
-    //
-    // Remove this when we have a way to represent non-canonical archetypes
-    // preserving sugar.
-    llvm::SaveAndRestore<const GenericSignatureImpl *> setGenericSig(
-        Options.GenericSig, decl->getGenericSignature().getPointer());
     printTypeLoc(TypeLoc(decl->getUnderlyingTypeRepr(), Ty));
     printDeclGenericRequirements(decl);
   }
@@ -3800,11 +3810,6 @@ void PrintAST::printPrimaryAssociatedTypes(ProtocolDecl *decl) {
 
 void PrintAST::visitProtocolDecl(ProtocolDecl *decl) {
   auto name = decl->getName();
-  if (Options.SuppressBitwiseCopyable &&
-      decl->getModuleContext()->isStdlibModule() &&
-      (decl->getNameStr() == "BitwiseCopyable")) {
-    name = decl->getASTContext().getIdentifier("_BitwiseCopyable");
-  }
   printDocumentationComment(decl);
   printAttributes(decl);
   printAccess(decl);
@@ -3863,13 +3868,13 @@ static void printParameterFlags(ASTPrinter &printer,
                                 const PrintOptions &options,
                                 const ParamDecl *param,
                                 ParameterTypeFlags flags,
-                                bool escaping) {
-  if (!options.excludeAttrKind(TypeAttrKind::Autoclosure) &&
-      flags.isAutoClosure())
-    printer.printAttrName("@autoclosure ");
-  if (!options.excludeAttrKind(TypeAttrKind::NoDerivative) &&
-      flags.isNoDerivative())
-    printer.printAttrName("@noDerivative ");
+                                bool escaping,
+                                bool isIsolatedToCaller = false) {
+  // Always print `nonisolated(nonsending)` specifier on a parameter
+  // first, to avoid any issues with ordering.
+  if (isIsolatedToCaller) {
+    printer.printKeyword("nonisolated(nonsending)", options, " ");
+  }
 
   switch (flags.getOwnershipSpecifier()) {
   case ParamSpecifier::Default:
@@ -3897,17 +3902,7 @@ static void printParameterFlags(ASTPrinter &printer,
   }
 
   if (flags.isSending()) {
-    if (!options.SuppressSendingArgsAndResults) {
-      printer.printAttrName("sending ");
-    } else if (flags.getOwnershipSpecifier() ==
-               ParamSpecifier::ImplicitlyCopyableConsuming) {
-      // Ok. We are suppressing sending. If our ownership specifier was
-      // originally implicitly copyable consuming our argument was being passed
-      // at +1. By not printing sending, we would be changing the API
-      // potentially to take the parameter at +0 instead of +1. To work around
-      // this, print out consuming so that we preserve the +1 parameter.
-      printer.printKeyword("__owned", options, " ");
-    }
+    printer.printKeyword("sending", options, " ");
   }
 
   if (flags.isIsolated()) {
@@ -3916,14 +3911,24 @@ static void printParameterFlags(ASTPrinter &printer,
       printer.printKeyword("isolated", options, " ");
   }
 
-  if (!options.excludeAttrKind(TypeAttrKind::Escaping) && escaping)
-    printer.printKeyword("@escaping", options, " ");
-
   if (flags.isCompileTimeLiteral())
     printer.printKeyword("_const", options, " ");
-  
+
+  if (!options.excludeAttrKind(TypeAttrKind::Autoclosure) &&
+      flags.isAutoClosure())
+    printer.printAttrName("@autoclosure ");
+  if (!options.excludeAttrKind(TypeAttrKind::NoDerivative) &&
+      flags.isNoDerivative())
+    printer.printAttrName("@noDerivative ");
+
+  // `inout` implies `@escaping`
+  if (flags.getOwnershipSpecifier() != ParamSpecifier::InOut) {
+    if (!options.excludeAttrKind(TypeAttrKind::Escaping) && escaping)
+      printer.printAttrName("@escaping ");
+  }
+
   if (flags.isConstValue())
-    printer.printKeyword("@const", options, " ");
+    printer.printAttrName("@const ");
 }
 
 void PrintAST::visitVarDecl(VarDecl *decl) {
@@ -3939,12 +3944,19 @@ void PrintAST::visitVarDecl(VarDecl *decl) {
   if (decl->isStatic() && Options.PrintStaticKeyword)
     printStaticKeyword(decl->getCorrectStaticSpelling());
   if (decl->getKind() == DeclKind::Var || Options.PrintParameterSpecifiers) {
+    // If InferPropertyIntroducerFromAccessors is set, turn all read-only
+    // properties to `let`.
+    auto introducer = decl->getIntroducer();
+    if (Options.InferPropertyIntroducerFromAccessors &&
+          !cast<VarDecl>(decl)->isSettable(nullptr))
+      introducer = VarDecl::Introducer::Let;
+
     // Map all non-let specifiers to 'var'.  This is not correct, but
     // SourceKit relies on this for info about parameter decls.
     
-    Printer.printIntroducerKeyword(
-      decl->getIntroducer() == VarDecl::Introducer::Let ? "let" : "var",
-      Options, " ");
+    bool printAsVar = (introducer != VarDecl::Introducer::Let ||
+                       isInObjCImpl(decl));
+    Printer.printIntroducerKeyword(printAsVar ? "var" : "let", Options, " ");
   }
   printContextIfNeeded(decl);
   recordDeclLoc(decl,
@@ -3969,8 +3981,7 @@ void PrintAST::visitVarDecl(VarDecl *decl) {
     Printer.printDeclResultTypePre(decl, tyLoc);
 
     PrintWithOpaqueResultTypeKeywordRAII x(Options);
-    printTypeLocForImplicitlyUnwrappedOptional(
-      tyLoc, decl->isImplicitlyUnwrappedOptional());
+    printTypeLoc(tyLoc, getNonRecursiveOptions(decl));
   }
 
   printAccessors(decl);
@@ -3982,7 +3993,8 @@ void PrintAST::visitParamDecl(ParamDecl *decl) {
 
 void PrintAST::printOneParameter(const ParamDecl *param,
                                  ParameterTypeFlags paramFlags,
-                                 bool ArgNameIsAPIByDefault) {
+                                 bool ArgNameIsAPIByDefault,
+                                 bool isEnumElement) {
   Printer.callPrintStructurePre(PrintStructureKind::FunctionParameter, param);
   SWIFT_DEFER {
     Printer.printStructurePost(PrintStructureKind::FunctionParameter, param);
@@ -4032,11 +4044,24 @@ void PrintAST::printOneParameter(const ParamDecl *param,
 
   printArgName();
 
+  auto interfaceTy = param->getInterfaceType();
+
+  // If type of this parameter is isolated to a caller, let's
+  // strip the isolation from the type to avoid printing it as
+  // part of the function type because that would break ordering
+  // between specifiers and attributes.
+  if (param->isCallerIsolated()) {
+    if (auto *funcTy = dyn_cast<AnyFunctionType>(interfaceTy.getPointer())) {
+      interfaceTy =
+          funcTy->withIsolation(FunctionTypeIsolation::forNonIsolated());
+    }
+  }
+
   TypeLoc TheTypeLoc;
   if (auto *repr = param->getTypeRepr()) {
-    TheTypeLoc = TypeLoc(repr, param->getInterfaceType());
+    TheTypeLoc = TypeLoc(repr, interfaceTy);
   } else {
-    TheTypeLoc = TypeLoc::withoutLoc(param->getInterfaceType());
+    TheTypeLoc = TypeLoc::withoutLoc(interfaceTy);
   }
 
   {
@@ -4047,12 +4072,15 @@ void PrintAST::printOneParameter(const ParamDecl *param,
     if (!param->isVariadic() &&
         !willUseTypeReprPrinting(TheTypeLoc, CurrentType, Options)) {
       auto type = TheTypeLoc.getType();
+
+      // We suppress `@escaping` on enum element parameters because it cannot
+      // be written explicitly in this position.
       printParameterFlags(Printer, Options, param, paramFlags,
-                          isEscaping(type));
+                          isEscaping(type) && !isEnumElement,
+                          param->isCallerIsolated());
     }
 
-    printTypeLocForImplicitlyUnwrappedOptional(
-      TheTypeLoc, param->isImplicitlyUnwrappedOptional());
+    printTypeLoc(TheTypeLoc, getNonRecursiveOptions(param));
   }
 
   if (param->isDefaultArgument() && Options.PrintDefaultArgumentValue) {
@@ -4091,8 +4119,10 @@ void PrintAST::printOneParameter(const ParamDecl *param,
 
 void PrintAST::printParameterList(ParameterList *PL,
                                   ArrayRef<AnyFunctionType::Param> params,
-                                  bool isAPINameByDefault) {
-  llvm::SaveAndRestore<bool> scope(Options.PrintSyntheticSILGenName, false);
+                                  bool isAPINameByDefault,
+                                  bool isEnumElement) {
+  PrintOptions::OverrideScope scope(Options);
+  OVERRIDE_PRINT_OPTION(scope, PrintSyntheticSILGenName, false);
 
   Printer.printStructurePre(PrintStructureKind::FunctionParameterList);
   SWIFT_DEFER {
@@ -4107,7 +4137,7 @@ void PrintAST::printParameterList(ParameterList *PL,
                     ? params[i].getParameterFlags()
                     : ParameterTypeFlags();
     printOneParameter(PL->get(i), paramFlags,
-                      isAPINameByDefault);
+                      isAPINameByDefault, isEnumElement);
   }
   Printer << ")";
 }
@@ -4142,7 +4172,8 @@ void PrintAST::printFunctionParameters(AbstractFunctionDecl *AFD) {
     parameterListTypes = funTy->getParams();
 
   printParameterList(BodyParams, parameterListTypes,
-                     AFD->argumentNameIsAPIByDefault());
+                     AFD->argumentNameIsAPIByDefault(),
+                     /*isEnumElement*/false);
 
   if (AFD->hasAsync() || AFD->hasThrows()) {
     Printer.printStructurePre(PrintStructureKind::EffectsSpecifiers);
@@ -4189,7 +4220,7 @@ bool PrintAST::printASTNodes(const ArrayRef<ASTNode> &Elements,
     } else if (auto stmt = element.dyn_cast<Stmt*>()) {
       visit(stmt);
     } else {
-      visit(element.get<Expr*>());
+      visit(cast<Expr *>(element));
     }
   }
   return PrintedSomething;
@@ -4215,6 +4246,7 @@ void PrintAST::visitAccessorDecl(AccessorDecl *decl) {
   case AccessorKind::Modify2:
   case AccessorKind::DidSet:
   case AccessorKind::MutableAddress:
+  case AccessorKind::Borrow:
     recordDeclLoc(decl,
       [&]{
         Printer << getAccessorLabel(decl->getAccessorKind());
@@ -4223,12 +4255,14 @@ void PrintAST::visitAccessorDecl(AccessorDecl *decl) {
   case AccessorKind::Set:
   case AccessorKind::WillSet:
   case AccessorKind::Init:
+  case AccessorKind::Mutate:
     recordDeclLoc(decl,
       [&]{
         Printer << getAccessorLabel(decl->getAccessorKind());
 
         auto params = decl->getParameters();
-        if (params->size() != 0 && !params->get(0)->isImplicit()) {
+        if (params->size() != 0 && !params->get(0)->isImplicit()
+              && Options.PrintExplicitAccessorParameters) {
           auto Name = params->get(0)->getName();
           if (!Name.empty()) {
             Printer << "(";
@@ -4308,13 +4342,14 @@ void PrintAST::visitFuncDecl(FuncDecl *decl) {
       if (proto && Options.TransformContext) {
         auto BaseType = Options.TransformContext->getBaseType();
         if (BaseType->getClassOrBoundGenericClass()) {
-          ResultTy = ResultTy.subst(
-            [&](Type t) -> Type {
-              if (t->isEqual(proto->getSelfInterfaceType()))
+          ResultTy = ResultTy.transformRec(
+            [&](TypeBase *t) -> std::optional<Type> {
+              if (isa<DependentMemberType>(t))
+                return t;
+              else if (t->isEqual(proto->getSelfInterfaceType()))
                 return DynamicSelfType::get(t, Ctx);
-              return t;
-            },
-            MakeAbstractConformanceForGenericType());
+              return std::nullopt;
+            });
           ResultTyLoc = TypeLoc::withoutLoc(ResultTy);
         }
       }
@@ -4332,14 +4367,12 @@ void PrintAST::visitFuncDecl(FuncDecl *decl) {
       Printer.printDeclResultTypePre(decl, ResultTyLoc);
       Printer.callPrintStructurePre(PrintStructureKind::FunctionReturnType);
 
-      if (!Options.SuppressSendingArgsAndResults) {
-        if (decl->hasSendingResult()) {
+      if (decl->hasSendingResult()) {
+        Printer << "sending ";
+      } else if (auto *ft = llvm::dyn_cast_if_present<AnyFunctionType>(
+                     decl->getInterfaceType())) {
+        if (ft->hasExtInfo() && ft->hasSendingResult()) {
           Printer << "sending ";
-        } else if (auto *ft = llvm::dyn_cast_if_present<AnyFunctionType>(
-                       decl->getInterfaceType())) {
-          if (ft->hasExtInfo() && ft->hasSendingResult()) {
-            Printer << "sending ";
-          }
         }
       }
 
@@ -4350,28 +4383,23 @@ void PrintAST::visitFuncDecl(FuncDecl *decl) {
       // such a case, look through the sending type repr since we handle it here
       // ourselves.
       bool usedTypeReprPrinting = false;
-      {
-        llvm::SaveAndRestore<PrintOptions> printOptions(Options);
-        Options.PrintOptionalAsImplicitlyUnwrapped =
-            decl->isImplicitlyUnwrappedOptional();
-        if (willUseTypeReprPrinting(ResultTyLoc, CurrentType, Options)) {
-          if (auto repr = ResultTyLoc.getTypeRepr()) {
-            // If we are printing a sending result... and we found that we have
-            // to use type repr printing, look through sending type repr.
-            // Sending was already applied in our caller.
-            if (auto *sendingRepr = dyn_cast<SendingTypeRepr>(repr)) {
-              repr = sendingRepr->getBase();
-            }
-            repr->print(Printer, Options);
-            usedTypeReprPrinting = true;
+      NonRecursivePrintOptions nrOptions = getNonRecursiveOptions(decl);
+      if (willUseTypeReprPrinting(ResultTyLoc, CurrentType, Options)) {
+        if (auto repr = ResultTyLoc.getTypeRepr()) {
+          // If we are printing a sending result... and we found that we have
+          // to use type repr printing, look through sending type repr.
+          // Sending was already applied in our caller.
+          if (auto *sendingRepr = dyn_cast<SendingTypeRepr>(repr)) {
+            repr = sendingRepr->getBase();
           }
+          repr->print(Printer, Options, nrOptions);
+          usedTypeReprPrinting = true;
         }
       }
 
       // If we printed using type repr printing, do not print again.
       if (!usedTypeReprPrinting) {
-        printTypeLocForImplicitlyUnwrappedOptional(
-            ResultTyLoc, decl->isImplicitlyUnwrappedOptional());
+        printTypeLoc(ResultTyLoc, nrOptions);
       }
       Printer.printStructurePost(PrintStructureKind::FunctionReturnType);
     }
@@ -4395,10 +4423,9 @@ void PrintAST::printEnumElement(EnumElementDecl *elt) {
     });
 
   if (auto *PL = elt->getParameterList()) {
-    llvm::SaveAndRestore<PrintOptions::ArgAndParamPrintingMode>
-      mode(Options.ArgAndParamPrinting,
-           PrintOptions::ArgAndParamPrintingMode::EnumElement);
-
+    PrintOptions::OverrideScope scope(Options);
+    OVERRIDE_PRINT_OPTION(scope, ArgAndParamPrinting,
+                          PrintOptions::ArgAndParamPrintingMode::EnumElement);
 
     auto params = ArrayRef<AnyFunctionType::Param>();
     if (!elt->isInvalid()) {
@@ -4411,12 +4438,9 @@ void PrintAST::printEnumElement(EnumElementDecl *elt) {
                    ->getParams();
     }
 
-    // @escaping is not valid in enum element position, even though the
-    // attribute is implicitly added. Ignore it when printing the parameters.
-    Options.ExcludeAttrList.push_back(TypeAttrKind::Escaping);
     printParameterList(PL, params,
-                       /*isAPINameByDefault*/true);
-    Options.ExcludeAttrList.pop_back();
+                       /*isAPINameByDefault*/true,
+                       /*isEnumElement*/true);
   }
 
   switch (Options.EnumRawValues) {
@@ -4504,7 +4528,8 @@ void PrintAST::visitSubscriptDecl(SubscriptDecl *decl) {
       params = type->castTo<AnyFunctionType>()->getParams();
     }
     printParameterList(decl->getIndices(), params,
-                       /*isAPINameByDefault*/false);
+                       /*isAPINameByDefault*/false,
+                       /*isEnumElement*/false);
   });
 
   {
@@ -4520,16 +4545,14 @@ void PrintAST::visitSubscriptDecl(SubscriptDecl *decl) {
     Printer.printDeclResultTypePre(decl, elementTy);
     Printer.callPrintStructurePre(PrintStructureKind::FunctionReturnType);
 
-    if (!Options.SuppressSendingArgsAndResults) {
       if (decl->getElementTypeRepr()) {
         if (isa<SendingTypeRepr>(decl->getResultTypeRepr()))
           Printer << "sending ";
       }
-    }
 
     PrintWithOpaqueResultTypeKeywordRAII x(Options);
-    printTypeLocForImplicitlyUnwrappedOptional(
-      elementTy, decl->isImplicitlyUnwrappedOptional());
+    auto nrOptions = getNonRecursiveOptions(decl);
+    printTypeLoc(elementTy, nrOptions);
     Printer.printStructurePost(PrintStructureKind::FunctionReturnType);
   }
 
@@ -4733,7 +4756,8 @@ void PrintAST::visitMacroDecl(MacroDecl *decl) {
             params = type->castTo<AnyFunctionType>()->getParams();
           }
           printParameterList(
-              decl->parameterList, params, /*isAPINameByDefault*/true);
+              decl->parameterList, params, /*isAPINameByDefault*/true,
+              /*isEnumElement*/false);
         }
       }
   );
@@ -4752,7 +4776,7 @@ void PrintAST::visitMacroDecl(MacroDecl *decl) {
 
     Printer.printDeclResultTypePre(decl, resultTypeLoc);
     Printer.callPrintStructurePre(PrintStructureKind::FunctionReturnType);
-    printTypeLocWithOptions(resultTypeLoc, Options);
+    printTypeLoc(resultTypeLoc);
     Printer.printStructurePost(PrintStructureKind::FunctionReturnType);
   }
 
@@ -4786,9 +4810,6 @@ void PrintAST::visitMacroDecl(MacroDecl *decl) {
         case BuiltinMacroKind::IsolationMacro:
           Printer << "IsolationMacro";
           break;
-        case BuiltinMacroKind::SwiftSettingsMacro:
-          Printer << "SwiftSettingsMacro";
-          break;
         }
         break;
 
@@ -4818,6 +4839,19 @@ void PrintAST::visitMacroExpansionDecl(MacroExpansionDecl *decl) {
   Printer << ')';
 }
 
+void CustomAttr::printCustomAttr(ASTPrinter &Printer, const PrintOptions &Options) const {
+  Printer.callPrintNamePre(PrintNameContext::Attribute);
+  Printer << "@";
+  if (auto type = getType())
+    type.print(Printer, Options);
+  else
+    getTypeRepr()->print(Printer, Options);
+  Printer.printNamePost(PrintNameContext::Attribute);
+  if (hasArgs() && Options.PrintExprs) {
+    PrintAST(Printer, Options).printArgumentList(argList);
+  }
+}
+
 void PrintAST::visitIntegerLiteralExpr(IntegerLiteralExpr *expr) {
   Printer << expr->getDigitsText();
 }
@@ -5513,9 +5547,6 @@ void PrintAST::visitMakeTemporarilyEscapableExpr(MakeTemporarilyEscapableExpr *e
 void PrintAST::visitProtocolMetatypeToObjectExpr(ProtocolMetatypeToObjectExpr *expr) {
 }
 
-void PrintAST::visitUnresolvedTypeConversionExpr(UnresolvedTypeConversionExpr *expr) {
-}
-
 void PrintAST::visitConditionalBridgeFromObjCExpr(ConditionalBridgeFromObjCExpr *expr) {
 }
 
@@ -5674,19 +5705,58 @@ void PrintAST::visitRepeatWhileStmt(RepeatWhileStmt *stmt) {
   visit(stmt->getCond());
 }
 
+void PrintAST::printAvailabilitySpec(AvailabilitySpec *spec) {
+  auto domainOrIdentifier = spec->getDomainOrIdentifier();
+  if (auto domain = domainOrIdentifier.getAsDomain()) {
+    Printer << domain->getNameForAttributePrinting();
+  } else {
+    Printer << domainOrIdentifier.getAsIdentifier().value();
+  }
+
+  if (!spec->getRawVersion().empty())
+    Printer << " " << spec->getRawVersion().getAsString();
+}
+
 void PrintAST::printStmtCondition(StmtCondition condition) {
   interleave(
       condition,
       [&](StmtConditionElement &elt) {
-        if (auto pattern = elt.getPatternOrNull()) {
-          printPattern(pattern);
-          auto initializer = elt.getInitializer();
-          if (initializer) {
+        switch (elt.getKind()) {
+        case StmtConditionElement::ConditionKind::CK_Boolean:
+          visit(elt.getBoolean());
+          break;
+
+        case StmtConditionElement::ConditionKind::CK_PatternBinding:
+          printPattern(elt.getPattern());
+          if (auto initializer = elt.getInitializer()) {
             Printer << " = ";
             visit(initializer);
           }
-        } else if (auto boolean = elt.getBooleanOrNull()) {
-          visit(boolean);
+          break;
+
+        case StmtConditionElement::ConditionKind::CK_Availability:
+          if (auto availability = elt.getAvailability()) {
+            Printer << (availability->isUnavailability()
+                            ? tok::pound_unavailable
+                            : tok::pound_available)
+                    << "(";
+
+            interleave(
+                availability->getQueries(),
+                [&](AvailabilitySpec *spec) { printAvailabilitySpec(spec); },
+                [&] { Printer << ", "; });
+
+            Printer << ")";
+          }
+          break;
+
+        case StmtConditionElement::ConditionKind::CK_HasSymbol:
+          if (auto hasSymbolInfo = elt.getHasSymbolInfo()) {
+            Printer << tok::pound__hasSymbol << "(";
+            visit(hasSymbolInfo->getSymbolExpr());
+            Printer << ")";
+          }
+          break;
         }
       },
       [&] { Printer << ", "; });
@@ -5866,7 +5936,7 @@ void printCType(ASTContext &Ctx, ASTPrinter &Printer, ExtInfo &info) {
 }
 
 namespace {
-class TypePrinter : public TypeVisitor<TypePrinter> {
+class TypePrinter : public TypeVisitor<TypePrinter, void, NonRecursivePrintOptions> {
   using super = TypeVisitor;
 
   ASTPrinter &Printer;
@@ -6001,12 +6071,17 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       Name = Mod->getASTContext().getIdentifier(ExportedModuleName);
     }
 
+    StringRef PublicModuleName = File->getPublicModuleName();
+    if (Options.UsePublicModuleNames && !PublicModuleName.empty()) {
+      Name = Mod->getASTContext().getIdentifier(PublicModuleName);
+    }
+
     if (Options.UseOriginallyDefinedInModuleNames) {
       Decl *D = Ty->getDecl();
       for (auto attr: D->getAttrs().getAttributes<OriginallyDefinedInAttr>()) {
-        Name = Mod->getASTContext()
-          .getIdentifier(const_cast<OriginallyDefinedInAttr*>(attr)
-                         ->ManglingModuleName);
+        Name = Mod->getASTContext().getIdentifier(
+            const_cast<OriginallyDefinedInAttr *>(attr)
+                ->getManglingModuleName());
         break;
       }
     }
@@ -6090,7 +6165,7 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     // If we printed a parent type or a module qualification, let the printer
     // know we're printing a type member so it escapes `Type` and `Protocol`.
     if (auto parent = Ty->getParent()) {
-      visitParentType(parent);
+      printParentType(parent);
       NameContext = PrintNameContext::TypeMember;
     } else if (shouldPrintFullyQualified(Ty)) {
       printModuleContext(Ty);
@@ -6100,31 +6175,27 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     printTypeDeclName(Ty, NameContext);
   }
 
-  void visit(Type T) {
+  void visit(Type T, NonRecursivePrintOptions nrOptions = std::nullopt) {
     Printer.printTypePre(TypeLoc::withoutLoc(T));
     SWIFT_DEFER { Printer.printTypePost(TypeLoc::withoutLoc(T)); };
 
-    super::visit(T);
+    super::visit(T, nrOptions);
   }
 
-  void visitErrorType(ErrorType *T) {
+  void visitErrorType(ErrorType *T, NonRecursivePrintOptions nrOptions) {
     if (auto originalType = T->getOriginalType()) {
       if (Options.PrintTypesForDebugging || Options.PrintInSILBody)
         Printer << "@error_type ";
       visit(originalType);
-    }
-    else
+    } else if (Options.PrintTypesForDebugging) {
       Printer << "<<error type>>";
-  }
-
-  void visitUnresolvedType(UnresolvedType *T) {
-    if (Options.PrintTypesForDebugging)
-      Printer << "<<unresolvedtype>>";
-    else
+    } else {
       Printer << "_";
+    }
   }
 
-  void visitErrorUnionType(ErrorUnionType *T) {
+  void visitErrorUnionType(ErrorUnionType *T,
+                           NonRecursivePrintOptions nrOptions) {
     Printer << "error_union(";
     interleave(T->getTerms(),
                [&](Type type) {
@@ -6135,7 +6206,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     Printer << ")";
   }
 
-  void visitPlaceholderType(PlaceholderType *T) {
+  void visitPlaceholderType(PlaceholderType *T,
+                            NonRecursivePrintOptions nrOptions) {
     if (Options.PrintTypesForDebugging) {
       Printer << "<<placeholder for ";
       auto originator = T->getOriginator();
@@ -6144,12 +6216,16 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       } else if (auto *VD = originator.dyn_cast<VarDecl *>()) {
         Printer << "decl = ";
         Printer << VD->getName();
-      } else if (originator.is<ErrorExpr *>()) {
+      } else if (isa<ErrorExpr *>(originator)) {
         Printer << "error_expr";
+      } else if (auto *errTy = originator.dyn_cast<ErrorType *>()) {
+        visit(errTy);
       } else if (auto *DMT = originator.dyn_cast<DependentMemberType *>()) {
         visit(DMT);
-      } else if (originator.is<TypeRepr *>()) {
+      } else if (isa<TypeRepr *>(originator)) {
         Printer << "type_repr";
+      } else if (isa<Pattern *>(originator)) {
+        Printer << "pattern";
       } else {
         assert(false && "unknown originator");
       }
@@ -6164,7 +6240,7 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
 #endif
 
 #define ASTPRINTER_PRINT_BUILTINTYPE(NAME)                                     \
-  void visit##NAME(NAME *T) {                                                  \
+  void visit##NAME(NAME *T, NonRecursivePrintOptions nrOptions) {              \
     SmallString<32> buffer;                                                    \
     T->getTypeName(buffer);                                                    \
     Printer << buffer;                                                         \
@@ -6184,10 +6260,22 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
   ASTPRINTER_PRINT_BUILTINTYPE(BuiltinIntegerType)
   ASTPRINTER_PRINT_BUILTINTYPE(BuiltinFloatType)
   ASTPRINTER_PRINT_BUILTINTYPE(BuiltinUnboundGenericType)
-  ASTPRINTER_PRINT_BUILTINTYPE(BuiltinFixedArrayType)
 #undef ASTPRINTER_PRINT_BUILTINTYPE
 
-  void visitSILTokenType(SILTokenType *T) {
+  void visitBuiltinFixedArrayType(BuiltinFixedArrayType *T,
+                                  NonRecursivePrintOptions nrOptions) {
+    SmallString<32> buffer;
+    T->getTypeName(buffer);
+    Printer << buffer;
+    Printer << "<";
+    visit(T->getSize());
+    Printer << ", ";
+    visit(T->getElementType());
+    Printer << ">";
+  }
+
+  void visitSILTokenType(SILTokenType *T,
+                         NonRecursivePrintOptions nrOptions) {
     Printer << BUILTIN_TYPE_NAME_SILTOKEN;
   }
 
@@ -6195,7 +6283,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     return Options.PrintForSIL || Options.PrintTypeAliasUnderlyingType;
   }
 
-  void visitTypeAliasType(TypeAliasType *T) {
+  void visitTypeAliasType(TypeAliasType *T,
+                          NonRecursivePrintOptions nrOptions) {
     if (shouldDesugarTypeAliasType(T)) {
       visit(T->getSinglyDesugaredType());
       return;
@@ -6212,11 +6301,12 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     }
   }
 
-  void visitLocatableType(LocatableType *T) {
+  void visitLocatableType(LocatableType *T,
+                          NonRecursivePrintOptions nrOptions) {
     visit(T->getSinglyDesugaredType());
   }
 
-  void visitPackType(PackType *T) {
+  void visitPackType(PackType *T, NonRecursivePrintOptions nrOptions) {
     if (Options.PrintExplicitPackTypes || Options.PrintTypesForDebugging)
       Printer << "Pack{";
 
@@ -6232,7 +6322,7 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       Printer << "}";
   }
 
-  void visitSILPackType(SILPackType *T) {
+  void visitSILPackType(SILPackType *T, NonRecursivePrintOptions nrOptions) {
     if (!T->isElementAddress())
       Printer << "@direct ";
     Printer << "Pack{";
@@ -6247,7 +6337,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     Printer << "}";
   }
 
-  void visitPackExpansionType(PackExpansionType *T) {
+  void visitPackExpansionType(PackExpansionType *T,
+                              NonRecursivePrintOptions nrOptions) {
     SmallVector<Type, 2> rootParameterPacks;
     T->getPatternType()->getTypeParameterPacks(rootParameterPacks);
 
@@ -6265,12 +6356,13 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     visit(T->getPatternType());
   }
 
-  void visitPackElementType(PackElementType *T) {
+  void visitPackElementType(PackElementType *T,
+                            NonRecursivePrintOptions nrOptions) {
     Printer << "/* level: " << T->getLevel() << " */ ";
     visit(T->getPackType());
   }
 
-  void visitTupleType(TupleType *T) {
+  void visitTupleType(TupleType *T, NonRecursivePrintOptions nrOptions) {
     Printer.callPrintStructurePre(PrintStructureKind::TupleType);
     SWIFT_DEFER { Printer.printStructurePost(PrintStructureKind::TupleType); };
 
@@ -6301,11 +6393,13 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     Printer << ")";
   }
 
-  void visitUnboundGenericType(UnboundGenericType *T) {
+  void visitUnboundGenericType(UnboundGenericType *T,
+                               NonRecursivePrintOptions nrOptions) {
     printQualifiedType(T);
   }
 
-  void visitBoundGenericType(BoundGenericType *T) {
+  void visitBoundGenericType(BoundGenericType *T,
+                             NonRecursivePrintOptions nrOptions) {
     if (Options.SynthesizeSugarOnTypes) {
       if (T->isArray()) {
         Printer << "[";
@@ -6335,7 +6429,7 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       printGenericArgs(T->getExpandedGenericArgs());
   }
 
-  void visitParentType(Type T) {
+  void printParentType(Type T) {
     /// Don't print the parent type if it's being printed in that type context.
     if (Options.TransformContext) {
        if (auto currentType = Options.TransformContext->getBaseType()) {
@@ -6362,35 +6456,37 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
                 enumTy->getDecl()->getClangDecl())) {
           if (namespaceDecl->isInline()) {
             if (auto parent = enumTy->getParent())
-              visitParentType(parent);
+              printParentType(parent);
             return;
           }
         }
       }
     }
-    PrintOptions innerOptions = Options;
-    innerOptions.SynthesizeSugarOnTypes = false;
+
+    PrintOptions::OverrideScope scope(Options);
+    OVERRIDE_PRINT_OPTION(scope, SynthesizeSugarOnTypes, false);
 
     if (auto sugarType = dyn_cast<SyntaxSugarType>(T.getPointer()))
       T = sugarType->getImplementationType();
 
-    TypePrinter(Printer, innerOptions).printWithParensIfNotSimple(T);
+    TypePrinter(Printer, Options).printWithParensIfNotSimple(T);
     Printer << ".";
   }
 
-  void visitEnumType(EnumType *T) {
+  void visitEnumType(EnumType *T, NonRecursivePrintOptions nrOptions) {
     printQualifiedType(T);
   }
 
-  void visitStructType(StructType *T) {
+  void visitStructType(StructType *T, NonRecursivePrintOptions nrOptions) {
     printQualifiedType(T);
   }
 
-  void visitClassType(ClassType *T) {
+  void visitClassType(ClassType *T, NonRecursivePrintOptions nrOptions) {
     printQualifiedType(T);
   }
 
-  void visitAnyMetatypeType(AnyMetatypeType *T) {
+  void visitAnyMetatypeType(AnyMetatypeType *T,
+                            NonRecursivePrintOptions nrOptions) {
     if (T->hasRepresentation()) {
       switch (T->getRepresentation()) {
       case MetatypeRepresentation::Thin:  Printer << "@thin ";  break;
@@ -6431,7 +6527,7 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     Printer << ".Type";
   }
 
-  void visitModuleType(ModuleType *T) {
+  void visitModuleType(ModuleType *T, NonRecursivePrintOptions nrOptions) {
     Printer << "module<";
     // Should print the module real name in case module aliasing is
     // used (see -module-alias), since that's the actual binary name.
@@ -6439,7 +6535,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     Printer << ">";
   }
 
-  void visitDynamicSelfType(DynamicSelfType *T) {
+  void visitDynamicSelfType(DynamicSelfType *T,
+                            NonRecursivePrintOptions nrOptions) {
     if (Options.PrintInSILBody) {
       Printer << "@dynamic_self ";
       visit(T->getSelfType());
@@ -6503,13 +6600,11 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       break;
 
     case FunctionTypeIsolation::Kind::Erased:
-      if (!Options.SuppressIsolatedAny)
-        Printer << "@isolated(any) ";
+      Printer << "@isolated(any) ";
       break;
 
-    case FunctionTypeIsolation::Kind::NonIsolatedCaller:
-      if (!Options.SuppressExecutionAttribute)
-        Printer << "@execution(caller) ";
+    case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
+      Printer << "nonisolated(nonsending) ";
       break;
     }
 
@@ -6754,7 +6849,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     Printer << ")";
   }
 
-  void visitFunctionType(FunctionType *T) {
+  void visitFunctionType(FunctionType *T,
+                         NonRecursivePrintOptions nrOptions) {
     Printer.callPrintStructurePre(PrintStructureKind::FunctionType);
     SWIFT_DEFER {
       Printer.printStructurePost(PrintStructureKind::FunctionType);
@@ -6785,8 +6881,7 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
 
     Printer << " -> ";
 
-    if (!Options.SuppressSendingArgsAndResults && T->hasExtInfo() &&
-        T->hasSendingResult()) {
+    if (T->hasExtInfo() && T->hasSendingResult()) {
       Printer.printKeyword("sending ", Options);
     }
 
@@ -6812,7 +6907,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     Printer << ">";
   }
 
-  void visitGenericFunctionType(GenericFunctionType *T) {
+  void visitGenericFunctionType(GenericFunctionType *T,
+                                NonRecursivePrintOptions nrOptions) {
     Printer.callPrintStructurePre(PrintStructureKind::FunctionType);
     SWIFT_DEFER {
       Printer.printStructurePost(PrintStructureKind::FunctionType);
@@ -6901,7 +6997,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     llvm_unreachable("bad convention");
   }
 
-  void visitSILFunctionType(SILFunctionType *T) {
+  void visitSILFunctionType(SILFunctionType *T,
+                            NonRecursivePrintOptions nrOptions) {
     printSILCoroutineKind(T->getCoroutineKind());
     printFunctionExtInfo(T);
     printCalleeConvention(T->getCalleeConvention());
@@ -6921,77 +7018,73 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     // Yeah, this is fiddly. In the end, we probably want all decls to have
     // substituted types in terms of a generic signature declared on the decl,
     // which would make this logic more uniform.
-    TypePrinter *sub = this;
-    std::optional<TypePrinter> subBuffer;
-    PrintOptions subOptions = Options;
-    if (auto substitutions = T->getPatternSubstitutions()) {
-      subOptions.GenericSig = nullptr;
-      subBuffer.emplace(Printer, subOptions);
-      sub = &*subBuffer;
-
-      GenericSignature sig = substitutions.getGenericSignature();
-
-      // The substituted signature is printed without inverse requirement
-      // desugaring, but also we drop conformances to Copyable and Escapable
-      // when constructing it.
-      sub->Printer << "@substituted ";
-      sub->printGenericSignature(sig,
-                                 PrintAST::PrintParams |
-                                 PrintAST::PrintRequirements);
-      sub->Printer << " ";
-    }
-
-    // Capture list used here to ensure we don't print anything using `this`
-    // printer, but only the sub-Printer.
-    [T, sub, &subOptions] {
-      sub->Printer << "(";
+
+    {
+      PrintOptions::OverrideScope scope(Options);
+
+      if (auto substitutions = T->getPatternSubstitutions()) {
+        OVERRIDE_PRINT_OPTION(scope, GenericSig, nullptr);
+
+        GenericSignature sig = substitutions.getGenericSignature();
+
+        // The substituted signature is printed without inverse requirement
+        // desugaring, but also we drop conformances to Copyable and Escapable
+        // when constructing it.
+        Printer << "@substituted ";
+        printGenericSignature(sig,
+                              PrintAST::PrintParams |
+                              PrintAST::PrintRequirements);
+        Printer << " ";
+      }
+
+      Printer << "(";
       bool first = true;
       unsigned paramIndex = 0;
       for (auto param : T->getParameters()) {
-        sub->Printer.printSeparator(first, ", ");
-        param.print(sub->Printer, subOptions,
+        Printer.printSeparator(first, ", ");
+        param.print(Printer, Options,
                     T->getLifetimeDependenceFor(paramIndex));
         paramIndex++;
       }
-      sub->Printer << ") -> ";
+      Printer << ") -> ";
 
-      sub->Printer.printLifetimeDependence(T->getLifetimeDependenceForResult());
+      Printer.printLifetimeDependence(T->getLifetimeDependenceForResult());
 
       bool parenthesizeResults = mustParenthesizeResults(T);
       if (parenthesizeResults)
-        sub->Printer << "(";
+        Printer << "(";
 
       first = true;
 
       for (auto yield : T->getYields()) {
-        sub->Printer.printSeparator(first, ", ");
-        sub->Printer << "@yields ";
+        Printer.printSeparator(first, ", ");
+        Printer << "@yields ";
         // TODO: Fix lifetime dependence printing here
-        yield.print(sub->Printer, subOptions);
+        yield.print(Printer, Options);
       }
 
       for (auto result : T->getResults()) {
-        sub->Printer.printSeparator(first, ", ");
-        result.print(sub->Printer, subOptions);
+        Printer.printSeparator(first, ", ");
+        result.print(Printer, Options);
       }
 
       if (T->hasErrorResult()) {
-        sub->Printer.printSeparator(first, ", ");
+        Printer.printSeparator(first, ", ");
         if (T->getErrorResult().getConvention() == ResultConvention::Owned)
-          sub->Printer << "@error ";
+          Printer << "@error ";
         else if (T->getErrorResult().getConvention() == ResultConvention::Indirect)
-          sub->Printer << "@error_indirect ";
+          Printer << "@error_indirect ";
         else if (T->getErrorResult().getConvention() == ResultConvention::Unowned)
-          sub->Printer << "@error_unowned ";
+          Printer << "@error_unowned ";
         else {
           assert(false && "Should have error, error_indirect, or error_unowned");
         }
-        T->getErrorResult().getInterfaceType().print(sub->Printer, subOptions);
+        T->getErrorResult().getInterfaceType().print(Printer, Options);
       }
 
       if (parenthesizeResults)
-        sub->Printer << ")";
-    }();
+        Printer << ")";
+    }
 
     // Both the pattern and invocation substitution types are always in
     // terms of the outer environment.  But this wouldn't necessarily be
@@ -7024,12 +7117,13 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     return isa<SILFunctionType>(T->getErrorResult().getInterfaceType());
   }
 
-  void visitSILBlockStorageType(SILBlockStorageType *T) {
+  void visitSILBlockStorageType(SILBlockStorageType *T,
+                                NonRecursivePrintOptions nrOptions) {
     Printer << "@block_storage ";
     printWithParensIfNotSimple(T->getCaptureType());
   }
 
-  void visitSILBoxType(SILBoxType *T) {
+  void visitSILBoxType(SILBoxType *T, NonRecursivePrintOptions nrOptions) {
     // Print attributes.
     if (T->getLayout()->capturesGenericEnvironment()) {
       Printer << "@captures_generics ";
@@ -7038,31 +7132,26 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     {
       // A box layout has its own independent generic environment. Don't try
       // to print it with the environment's generic params.
-      PrintOptions subOptions = Options;
-      subOptions.GenericSig = nullptr;
-      TypePrinter sub(Printer, subOptions);
-
-      // Capture list used here to ensure we don't print anything using `this`
-      // printer, but only the sub-Printer.
-      [&sub, T, options=Options]{
-        if (auto sig = T->getLayout()->getGenericSignature()) {
-          sub.printGenericSignature(sig,
-                          PrintAST::PrintParams |
-                          PrintAST::defaultGenericRequirementFlags(options));
-          sub.Printer << " ";
-        }
-        sub.Printer << "{";
-        interleave(T->getLayout()->getFields(),
-                   [&](const SILField &field) {
-                     sub.Printer <<
-                       (field.isMutable() ? " var " : " let ");
-                     sub.visit(field.getLoweredType());
-                   },
-                   [&]{
-                     sub.Printer << ",";
-                   });
-        sub.Printer << " }";
-      }();
+      PrintOptions::OverrideScope scope(Options);
+      OVERRIDE_PRINT_OPTION(scope, GenericSig, nullptr);
+
+      if (auto sig = T->getLayout()->getGenericSignature()) {
+        printGenericSignature(sig,
+                        PrintAST::PrintParams |
+                        PrintAST::defaultGenericRequirementFlags(Options));
+        Printer << " ";
+      }
+      Printer << "{";
+      interleave(T->getLayout()->getFields(),
+                 [&](const SILField &field) {
+                   Printer <<
+                     (field.isMutable() ? " var " : " let ");
+                   visit(field.getLoweredType());
+                 },
+                 [&]{
+                   Printer << ",";
+                 });
+      Printer << " }";
     }
 
     // The arguments to the layout, if any, do come from the outer environment.
@@ -7071,12 +7160,14 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     }
   }
 
-  void visitSILMoveOnlyWrappedType(SILMoveOnlyWrappedType *T) {
+  void visitSILMoveOnlyWrappedType(SILMoveOnlyWrappedType *T,
+                                   NonRecursivePrintOptions nrOptions) {
     Printer << "@moveOnly ";
     printWithParensIfNotSimple(T->getInnerType());
   }
 
-  void visitArraySliceType(ArraySliceType *T) {
+  void visitArraySliceType(ArraySliceType *T,
+                           NonRecursivePrintOptions nrOptions) {
     if (Options.AlwaysDesugarArraySliceTypes) {
       visit(T->getDesugaredType());
     } else {
@@ -7086,19 +7177,21 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     }
   }
 
-  void visitInlineArrayType(InlineArrayType *T) {
+  void visitInlineArrayType(InlineArrayType *T,
+                            NonRecursivePrintOptions nrOptions) {
     if (Options.AlwaysDesugarInlineArrayTypes) {
       visit(T->getDesugaredType());
     } else {
       Printer << "[";
       visit(T->getCountType());
-      Printer << " x ";
+      Printer << " of ";
       visit(T->getElementType());
       Printer << "]";
     }
   }
 
-  void visitDictionaryType(DictionaryType *T) {
+  void visitDictionaryType(DictionaryType *T,
+                           NonRecursivePrintOptions nrOptions) {
     if (Options.AlwaysDesugarDictionaryTypes) {
       visit(T->getDesugaredType());
     } else {
@@ -7110,27 +7203,22 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     }
   }
 
-  void visitOptionalType(OptionalType *T) {
-    auto printAsIUO = Options.PrintOptionalAsImplicitlyUnwrapped;
+  void visitOptionalType(OptionalType *T,
+                         NonRecursivePrintOptions nrOptions) {
     if (Options.AlwaysDesugarOptionalTypes) {
-      visit(T->getDesugaredType());
+      visit(T->getDesugaredType(), nrOptions);
       return;
     } else {
-      // Printing optionals with a trailing '!' applies only to
-      // top-level optionals, not to any nested within.
-      const_cast<PrintOptions &>(Options).PrintOptionalAsImplicitlyUnwrapped =
-          false;
       printWithParensIfNotSimple(T->getBaseType());
-      const_cast<PrintOptions &>(Options).PrintOptionalAsImplicitlyUnwrapped =
-          printAsIUO;
-      if (printAsIUO)
+      if (nrOptions & NonRecursivePrintOption::ImplicitlyUnwrappedOptional)
         Printer << "!";
       else
         Printer << "?";
     }
   }
 
-  void visitVariadicSequenceType(VariadicSequenceType *T) {
+  void visitVariadicSequenceType(VariadicSequenceType *T,
+                                 NonRecursivePrintOptions nrOptions) {
     if (Options.PrintForSIL) {
       Printer << "[";
       visit(T->getBaseType());
@@ -7141,11 +7229,13 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     }
   }
 
-  void visitProtocolType(ProtocolType *T) {
+  void visitProtocolType(ProtocolType *T,
+                         NonRecursivePrintOptions nrOptions) {
     printQualifiedType(T);
   }
 
-  void visitProtocolCompositionType(ProtocolCompositionType *T) {
+  void visitProtocolCompositionType(ProtocolCompositionType *T,
+                                    NonRecursivePrintOptions nrOptions) {
     interleave(T->getMembers(), [&](Type Ty) { visit(Ty); },
         [&] { Printer << " & "; });
 
@@ -7171,7 +7261,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       Printer.printKeyword("Any", Options);
   }
 
-  void visitParameterizedProtocolType(ParameterizedProtocolType *T) {
+  void visitParameterizedProtocolType(ParameterizedProtocolType *T,
+                                      NonRecursivePrintOptions nrOptions) {
     visit(T->getBaseType());
     Printer << "<";
     interleave(T->getArgs(), [&](Type Ty) { visit(Ty); },
@@ -7179,7 +7270,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     Printer << ">";
   }
 
-  void visitExistentialType(ExistentialType *T) {
+  void visitExistentialType(ExistentialType *T,
+                            NonRecursivePrintOptions nrOptions) {
     if (T->shouldPrintWithAny())
       Printer << "any ";
 
@@ -7195,24 +7287,32 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     }
   }
 
-  void visitBuiltinTupleType(BuiltinTupleType *T) {
+  void visitBuiltinTupleType(BuiltinTupleType *T,
+                             NonRecursivePrintOptions nrOptions) {
     printQualifiedType(T);
   }
 
-  void visitLValueType(LValueType *T) {
+  void visitLValueType(LValueType *T, NonRecursivePrintOptions nrOptions) {
     Printer << "@lvalue ";
     visit(T->getObjectType());
   }
 
-  void visitInOutType(InOutType *T) {
+  void visitInOutType(InOutType *T, NonRecursivePrintOptions nrOptions) {
     Printer << tok::kw_inout << " ";
-    visit(T->getObjectType());
+    // Apply the non-recursive options to the object type of `inout`.
+    // This might seem a little weird, but it's convenient for the uncommon
+    // cases that we do actually print InOutType.
+    visit(T->getObjectType(), nrOptions);
   }
 
-  void visitExistentialArchetypeType(ExistentialArchetypeType *T) {
+  void visitExistentialArchetypeType(ExistentialArchetypeType *T,
+                                     NonRecursivePrintOptions nrOptions) {
     if (Options.PrintForSIL) {
       auto *env = T->getGenericEnvironment();
 
+      if (!T->isRoot())
+        Printer << '(';
+
       Printer << "@opened(\"" << env->getOpenedExistentialUUID() << "\", ";
       auto existentialTy = env->maybeApplyOuterContextSubstitutions(
           env->getOpenedExistentialType());
@@ -7224,12 +7324,12 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       auto interfaceTy = T->getInterfaceType();
       auto selfTy = interfaceTy->getRootGenericParam();
       auto &ctx = selfTy->getASTContext();
-      newAlternativeTypeNames[selfTy->getCanonicalType()] = ctx.Id_Self;
+      Identifier selfId = (T->isRoot() ? ctx.Id_Self : ctx.getIdentifier("Self)"));
+      newAlternativeTypeNames[selfTy->getCanonicalType()] = selfId;
 
-      PrintOptions subOptions = Options;
-      subOptions.AlternativeTypeNames = &newAlternativeTypeNames;
-      TypePrinter sub(Printer, subOptions);
-      sub.visit(interfaceTy);
+      PrintOptions::OverrideScope scope(Options);
+      OVERRIDE_PRINT_OPTION(scope, AlternativeTypeNames, &newAlternativeTypeNames);
+      visit(interfaceTy);
     } else {
       visit(T->getExistentialType());
     }
@@ -7281,7 +7381,8 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     }, LookUpConformanceInModule());
   }
 
-  void visitElementArchetypeType(ElementArchetypeType *T) {
+  void visitElementArchetypeType(ElementArchetypeType *T,
+                                 NonRecursivePrintOptions nrOptions) {
     if (Options.PrintForSIL) {
       Printer << "@pack_element(\"" << T->getOpenedElementID() << "\") ";
       auto packTy = findPackForElementArchetype(T);
@@ -7333,7 +7434,7 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
 
     auto *memberTy = interfaceTy->castTo<DependentMemberType>();
     if (auto *paramTy = memberTy->getBase()->getAs<GenericTypeParamType>())
-      visitParentType(env->mapTypeIntoContext(paramTy));
+      printParentType(env->mapTypeIntoContext(paramTy));
     else {
       printArchetypeCommon(memberTy->getBase(), env);
       Printer << ".";
@@ -7342,11 +7443,13 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     printDependentMember(memberTy);
   }
 
-  void visitPrimaryArchetypeType(PrimaryArchetypeType *T) {
+  void visitPrimaryArchetypeType(PrimaryArchetypeType *T,
+                                 NonRecursivePrintOptions nrOptions) {
     printArchetypeCommon(T->getInterfaceType(), T->getGenericEnvironment());
   }
 
-  void visitOpaqueTypeArchetypeType(OpaqueTypeArchetypeType *T) {
+  void visitOpaqueTypeArchetypeType(OpaqueTypeArchetypeType *T,
+                                    NonRecursivePrintOptions nrOptions) {
     auto interfaceTy = T->getInterfaceType();
     auto *paramTy = interfaceTy->getAs<GenericTypeParamType>();
 
@@ -7387,11 +7490,6 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       if (auto existential = constraint->getAs<ExistentialType>())
         constraint = existential->getConstraintType();
 
-      // Opaque archetype substitutions are always canonical, so re-sugar the
-      // constraint type using the owning declaration's generic parameter names.
-      if (genericSig)
-        constraint = genericSig->getSugaredType(constraint);
-
       visit(constraint);
       return;
     }
@@ -7414,10 +7512,37 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       Printer << ") __";
 
       if (genericSig) {
-        printGenericArgs(decl->getASTContext(),
-                         genericSig.getGenericParams(),
-                         T->getSubstitutions().getReplacementTypes());
+        auto &ctx = decl->getASTContext();
+        auto params = genericSig.getGenericParams();
+        auto args = T->getSubstitutions().getReplacementTypes();
+
+        // Use the new "nested" syntax if there is at least one parameter pack,
+        // because that case didn't round trip at all before anyway. Otherwise,
+        // use the old "flat" syntax, even when the owner declaration is in a
+        // nested generic context, because we want the generated swiftinterface
+        // to continue to work on old compilers.
+        if (genericSig->hasParameterPack()) {
+          bool first = true;
+
+          while (!params.empty()) {
+            if (!first) { Printer << ".__"; }
+            first = false;
+
+            unsigned end = 1;
+            unsigned depth = params.front()->getDepth();
+            while (end < params.size() && params[end]->getDepth() == depth) {
+              ++end;
+            }
+
+            printGenericArgs(ctx, params.take_front(end), args.take_front(end));
+            params = params.slice(end);
+            args = args.slice(end);
+          }
+        } else {
+          printGenericArgs(ctx, params, args);
+        }
       }
+
       return;
     }
     case PrintOptions::OpaqueReturnTypePrintingMode::Description: {
@@ -7436,11 +7561,13 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     }
   }
 
-  void visitPackArchetypeType(PackArchetypeType *T) {
+  void visitPackArchetypeType(PackArchetypeType *T,
+                              NonRecursivePrintOptions nrOptions) {
     printArchetypeCommon(T->getInterfaceType(), T->getGenericEnvironment());
   }
 
-  void visitGenericTypeParamType(GenericTypeParamType *T) {
+  void visitGenericTypeParamType(GenericTypeParamType *T,
+                                 NonRecursivePrintOptions nrOptions) {
     auto printPrefix = [&]{
       if (T->isParameterPack()) printEach();
     };
@@ -7505,20 +7632,23 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     }
   }
 
-  void visitDependentMemberType(DependentMemberType *T) {
-    visitParentType(T->getBase());
+  void visitDependentMemberType(DependentMemberType *T,
+                                NonRecursivePrintOptions nrOptions) {
+    printParentType(T->getBase());
     printDependentMember(T);
   }
 
 #define REF_STORAGE(Name, name, ...) \
-  void visit##Name##StorageType(Name##StorageType *T) { \
+  void visit##Name##StorageType(Name##StorageType *T, \
+                                NonRecursivePrintOptions nrOptions) { \
     if (Options.PrintStorageRepresentationAttrs) \
       Printer << "@sil_" #name " "; \
-    visit(T->getReferentType()); \
+    visit(T->getReferentType(), nrOptions); \
   }
 #include "swift/AST/ReferenceStorage.def"
 
-  void visitTypeVariableType(TypeVariableType *T) {
+  void visitTypeVariableType(TypeVariableType *T,
+                             NonRecursivePrintOptions nrOptions) {
     if (Options.PrintTypesForDebugging) {
       Printer << "$T" << T->getID();
       return;
@@ -7527,7 +7657,7 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     Printer << "_";
   }
 
-  void visitIntegerType(IntegerType *T) {
+  void visitIntegerType(IntegerType *T, NonRecursivePrintOptions nrOptions) {
     if (T->isNegative()) {
       Printer << "-";
     }
@@ -7537,11 +7667,13 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
 };
 } // unnamed namespace
 
-void Type::print(raw_ostream &OS, const PrintOptions &PO) const {
+void Type::print(raw_ostream &OS, const PrintOptions &PO,
+                 NonRecursivePrintOptions nrOptions) const {
   StreamPrinter Printer(OS);
-  print(Printer, PO);
+  print(Printer, PO, nrOptions);
 }
-void Type::print(ASTPrinter &Printer, const PrintOptions &PO) const {
+void Type::print(ASTPrinter &Printer, const PrintOptions &PO,
+                 NonRecursivePrintOptions nrOptions) const {
   if (isNull()) {
     if (!PO.AllowNullTypes) {
       // Use report_fatal_error instead of assert to trap in release builds too.
@@ -7550,7 +7682,7 @@ void Type::print(ASTPrinter &Printer, const PrintOptions &PO) const {
     Printer << "<null>";
     return;
   }
-  TypePrinter(Printer, PO).visit(*this);
+  TypePrinter(Printer, PO).visit(*this, nrOptions);
 }
 
 void AnyFunctionType::printParams(ArrayRef<AnyFunctionType::Param> Params,
@@ -7613,10 +7745,12 @@ void LayoutConstraintInfo::print(ASTPrinter &Printer,
   }
 }
 
-void GenericSignatureImpl::print(raw_ostream &OS, PrintOptions PO) const {
+void GenericSignatureImpl::print(raw_ostream &OS,
+                                 const PrintOptions &PO) const {
   GenericSignature(const_cast<GenericSignatureImpl *>(this)).print(OS, PO);
 }
-void GenericSignatureImpl::print(ASTPrinter &Printer, PrintOptions PO) const {
+void GenericSignatureImpl::print(ASTPrinter &Printer,
+                                 const PrintOptions &PO) const {
   GenericSignature(const_cast<GenericSignatureImpl *>(this)).print(Printer, PO);
 }
 
@@ -7776,6 +7910,10 @@ static StringRef getStringForResultConvention(ResultConvention conv) {
   case ResultConvention::UnownedInnerPointer: return "@unowned_inner_pointer ";
   case ResultConvention::Autoreleased: return "@autoreleased ";
   case ResultConvention::Pack: return "@pack_out ";
+  case ResultConvention::GuaranteedAddress:
+    return "@guaranteed_addr ";
+  case ResultConvention::Guaranteed:
+    return "@guaranteed ";
   }
   llvm_unreachable("bad result convention");
 }
@@ -7804,44 +7942,48 @@ void SILResultInfo::print(ASTPrinter &Printer, const PrintOptions &Opts) const {
   getInterfaceType().print(Printer, Opts);
 }
 
-std::string Type::getString(const PrintOptions &PO) const {
+std::string Type::getString(const PrintOptions &PO,
+                            NonRecursivePrintOptions nrOptions) const {
   std::string Result;
   llvm::raw_string_ostream OS(Result);
-  print(OS, PO);
+  print(OS, PO, nrOptions);
   return OS.str();
 }
 
-std::string TypeBase::getString(const PrintOptions &PO) const {
+std::string TypeBase::getString(const PrintOptions &PO,
+                                NonRecursivePrintOptions nrOptions) const {
   std::string Result;
   llvm::raw_string_ostream OS(Result);
-  print(OS, PO);
+  print(OS, PO, nrOptions);
   return OS.str();
 }
 
-std::string Type::getStringAsComponent(const PrintOptions &PO) const {
+std::string Type::getStringAsComponent(const PrintOptions &PO,
+                                       NonRecursivePrintOptions nrOptions) const {
   std::string Result;
   llvm::raw_string_ostream OS(Result);
 
   if (getPointer()->hasSimpleTypeRepr()) {
-    print(OS, PO);
+    print(OS, PO, nrOptions);
   } else {
     OS << "(";
-    print(OS, PO);
+    print(OS, PO, nrOptions);
     OS << ")";
   }
 
   return OS.str();
 }
 
-std::string TypeBase::getStringAsComponent(const PrintOptions &PO) const {
+std::string TypeBase::getStringAsComponent(const PrintOptions &PO,
+                                           NonRecursivePrintOptions nrOptions) const {
   std::string Result;
   llvm::raw_string_ostream OS(Result);
 
   if (hasSimpleTypeRepr()) {
-    print(OS, PO);
+    print(OS, PO, nrOptions);
   } else {
     OS << "(";
-    print(OS, PO);
+    print(OS, PO, nrOptions);
     OS << ")";
   }
 
@@ -7852,11 +7994,13 @@ void TypeBase::print() const {
   print(llvm::errs());
   llvm::errs() << '\n';
 }
-void TypeBase::print(raw_ostream &OS, const PrintOptions &PO) const {
-  Type(const_cast<TypeBase *>(this)).print(OS, PO);
+void TypeBase::print(raw_ostream &OS, const PrintOptions &PO,
+                     NonRecursivePrintOptions nrOptions) const {
+  Type(const_cast<TypeBase *>(this)).print(OS, PO, nrOptions);
 }
-void TypeBase::print(ASTPrinter &Printer, const PrintOptions &PO) const {
-  Type(const_cast<TypeBase *>(this)).print(Printer, PO);
+void TypeBase::print(ASTPrinter &Printer, const PrintOptions &PO,
+                     NonRecursivePrintOptions nrOptions) const {
+  Type(const_cast<TypeBase *>(this)).print(Printer, PO, nrOptions);
 }
 
 std::string LayoutConstraint::getString(const PrintOptions &PO) const {
diff --git a/lib/AST/ASTScope.cpp b/lib/AST/ASTScope.cpp
index 4583ac892c517..c49c6c49756f5 100644
--- a/lib/AST/ASTScope.cpp
+++ b/lib/AST/ASTScope.cpp
@@ -356,6 +356,8 @@ SourceRange NominalTypeScope::getBraces() const { return decl->getBraces(); }
 
 NullablePtr<NominalTypeDecl>
 ExtensionScope::getCorrespondingNominalTypeDecl() const {
+  if (!decl->hasBeenBound())
+    return nullptr;
   return decl->getExtendedNominal();
 }
 
diff --git a/lib/AST/ASTScopeCreation.cpp b/lib/AST/ASTScopeCreation.cpp
index 40d0bc8b60b9d..d95675b40b24b 100644
--- a/lib/AST/ASTScopeCreation.cpp
+++ b/lib/AST/ASTScopeCreation.cpp
@@ -339,12 +339,12 @@ ASTSourceFileScope::ASTSourceFileScope(SourceFile *SF,
     }
     case MacroRole::Body: {
       auto expansion = SF->getMacroExpansion();
-      if (expansion.is<Decl *>()) {
+      if (isa<Decl *>(expansion)) {
         // Use the end location of the function decl itself as the parentLoc
         // for the new function body scope. This is different from the end
         // location of the original source range, which is after the end of the
         // function decl.
-        bodyForDecl = cast<AbstractFunctionDecl>(expansion.get<Decl *>());
+        bodyForDecl = cast<AbstractFunctionDecl>(cast<Decl *>(expansion));
         parentLoc = expansion.getEndLoc();
         break;
       }
@@ -404,6 +404,7 @@ class NodeAdder
   VISIT_AND_IGNORE(ParamDecl)
   VISIT_AND_IGNORE(MissingDecl)
   VISIT_AND_IGNORE(MissingMemberDecl)
+  VISIT_AND_IGNORE(UsingDecl)
 
   // This declaration is handled from the PatternBindingDecl
   VISIT_AND_IGNORE(VarDecl)
@@ -632,7 +633,7 @@ ASTScopeImpl *ScopeCreator::addToScopeTreeAndReturnInsertionPoint(
     return adder.visit(p, parent, *this);
   if (auto *p = n.dyn_cast<Expr *>())
     return adder.visit(p, parent, *this);
-  auto *p = n.get<Stmt *>();
+  auto *p = cast<Stmt *>(n);
   return adder.visit(p, parent, *this);
 }
 
@@ -661,7 +662,7 @@ void ScopeCreator::addChildrenForKnownAttributes(Decl *decl,
     if (isa<DifferentiableAttr>(attr))
       relevantAttrs.push_back(attr);
 
-    if (isa<SpecializeAttr>(attr))
+    if (isa<AbstractSpecializeAttr>(attr))
       relevantAttrs.push_back(attr);
 
     if (isa<CustomAttr>(attr))
@@ -679,7 +680,7 @@ void ScopeCreator::addChildrenForKnownAttributes(Decl *decl,
     if (auto *diffAttr = dyn_cast<DifferentiableAttr>(attr)) {
       constructExpandAndInsert<DifferentiableAttributeScope>(
           parent, diffAttr, decl);
-    } else if (auto *specAttr = dyn_cast<SpecializeAttr>(attr)) {
+    } else if (auto *specAttr = dyn_cast<AbstractSpecializeAttr>(attr)) {
       if (auto *afd = dyn_cast<AbstractFunctionDecl>(decl)) {
         constructExpandAndInsert<SpecializeAttributeScope>(
             parent, specAttr, afd);
diff --git a/lib/AST/ASTScopeLookup.cpp b/lib/AST/ASTScopeLookup.cpp
index ed80e1440e30e..80e17ecbb2a3a 100644
--- a/lib/AST/ASTScopeLookup.cpp
+++ b/lib/AST/ASTScopeLookup.cpp
@@ -378,10 +378,10 @@ bool CaseLabelItemScope::lookupLocalsOrMembers(DeclConsumer consumer) const {
 }
 
 bool CaseStmtBodyScope::lookupLocalsOrMembers(DeclConsumer consumer) const {
-  for (auto *var : stmt->getCaseBodyVariablesOrEmptyArray())
+  for (auto *var : stmt->getCaseBodyVariables()) {
     if (consumer.consume({var}))
-        return true;
-
+      return true;
+  }
   return false;
 }
 
@@ -703,42 +703,24 @@ lookupEnclosingABIAttributeScope(SourceFile *sourceFile, SourceLoc loc) {
   return nullptr;
 }
 
-static std::pair<CatchNode, const BraceStmtScope *>
-getCatchNodeBody(const ASTScopeImpl *scope, CatchNode node) {
-  const auto &children = scope->getChildren();
-  if (children.empty())
-    return { CatchNode(), nullptr };
-
-  auto stmt = dyn_cast<BraceStmtScope>(children[0]);
-  if (!stmt || stmt->getStmt()->empty())
-    return { CatchNode(), nullptr };
-
-  return std::make_pair(node, stmt);
-}
-
 /// Retrieve the catch node associated with this scope, if any.
-static std::pair<CatchNode, const BraceStmtScope *>
-getCatchNode(const ASTScopeImpl *scope) {
+static CatchNode getCatchNode(const ASTScopeImpl *scope) {
   // Closures introduce a catch scope for errors initiated in their body.
   if (auto closureParams = dyn_cast<ClosureParametersScope>(scope)) {
-    if (auto closure = dyn_cast<ClosureExpr>(closureParams->closureExpr)) {
-      return getCatchNodeBody(scope, const_cast<ClosureExpr *>(closure));
-    }
+    if (auto closure = dyn_cast<ClosureExpr>(closureParams->closureExpr))
+      return closure;
   }
 
   // Functions introduce a catch scope for errors initiated in their body.
-  if (auto function = dyn_cast<FunctionBodyScope>(scope)) {
-    return getCatchNodeBody(
-        scope, const_cast<AbstractFunctionDecl *>(function->decl));
-  }
+  if (auto function = dyn_cast<FunctionBodyScope>(scope))
+    return function->decl;
 
   // Do..catch blocks introduce a catch scope for errors initiated in the `do`
   // body.
-  if (auto doCatch = dyn_cast<DoCatchStmtScope>(scope)) {
-    return getCatchNodeBody(scope, const_cast<DoCatchStmt *>(doCatch->stmt));
-  }
+  if (auto doCatch = dyn_cast<DoCatchStmtScope>(scope))
+    return doCatch->stmt;
 
-  return { CatchNode(), nullptr };
+  return CatchNode();
 }
 
 /// Check whether the given location precedes the start of the catch location
@@ -767,15 +749,22 @@ CatchNode ASTScopeImpl::lookupCatchNode(ModuleDecl *module, SourceLoc loc) {
   ASTScopeAssert(innermost->getWasExpanded(),
                  "If looking in a scope, it must have been expanded.");
 
-  // Look for a body scope that's the
+  // Look for a body scope that's the direct descendent of a catch node.
   const BraceStmtScope *innerBodyScope = nullptr;
   for (auto scope = innermost; scope; scope = scope->getParent().getPtrOrNull()) {
     // If we are at a catch node and in the body of the region from which that
     // node catches thrown errors, we have our result.
-    auto caught = getCatchNode(scope);
-    if (caught.first && caught.second == innerBodyScope &&
-        !locationIsPriorToStartOfCatchScope(loc, caught.first)) {
-      return caught.first;
+    if (innerBodyScope && innerBodyScope->getParent() == scope) {
+      // For a macro expansion, we may have an intermediate source file scope,
+      // we can look through it.
+      auto catchScope = scope;
+      if (auto *sfScope = dyn_cast<ASTSourceFileScope>(catchScope)) {
+        if (auto parent = sfScope->getParent())
+          catchScope = parent.get();
+      }
+      auto caught = getCatchNode(catchScope);
+      if (caught && !locationIsPriorToStartOfCatchScope(loc, caught))
+          return caught;
     }
 
     // If this is a try scope for a try! or try?, it catches the error.
diff --git a/lib/AST/ASTScopePrinting.cpp b/lib/AST/ASTScopePrinting.cpp
index 399fbca7d2cae..2ff3cb5a38fcc 100644
--- a/lib/AST/ASTScopePrinting.cpp
+++ b/lib/AST/ASTScopePrinting.cpp
@@ -29,6 +29,7 @@
 #include "swift/AST/Stmt.h"
 #include "swift/AST/TypeRepr.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Basic/STLExtras.h"
 #include "llvm/Support/Compiler.h"
 #include <algorithm>
@@ -71,15 +72,11 @@ void ASTScopeImpl::dumpOneScopeMapLocation(
 
 void ASTScopeImpl::abortWithVerificationError(
     llvm::function_ref<void(llvm::raw_ostream &)> messageFn) const {
-  llvm::SmallString<0> errorStr;
-  llvm::raw_svector_ostream out(errorStr);
-
-  out << "ASTScopeImpl verification error in source file '"
-      << getSourceFile()->getFilename() << "':\n";
-  messageFn(out);
-
-  llvm::PrettyStackTraceString trace(errorStr.c_str());
-  abort();
+  ABORT([&](auto &out) {
+    out << "ASTScopeImpl verification error in source file '"
+        << getSourceFile()->getFilename() << "':\n";
+    messageFn(out);
+  });
 }
 
 #pragma mark printing
diff --git a/lib/AST/ASTVerifier.cpp b/lib/AST/ASTVerifier.cpp
index 76d2454e981f5..dca0ef13b3bd1 100644
--- a/lib/AST/ASTVerifier.cpp
+++ b/lib/AST/ASTVerifier.cpp
@@ -248,8 +248,8 @@ class Verifier : public ASTWalker {
 
   Verifier(PointerUnion<ModuleDecl *, SourceFile *> M, DeclContext *DC)
       : M(M),
-        Ctx(M.is<ModuleDecl *>() ? M.get<ModuleDecl *>()->getASTContext()
-                                 : M.get<SourceFile *>()->getASTContext()),
+        Ctx(isa<ModuleDecl *>(M) ? cast<ModuleDecl *>(M)->getASTContext()
+                                 : cast<SourceFile *>(M)->getASTContext()),
         Out(llvm::errs()), HadError(Ctx.hadError()) {
     pushScope(DC);
   }
@@ -269,7 +269,7 @@ class Verifier : public ASTWalker {
     if (auto sourceFile = M.dyn_cast<SourceFile *>())
       return sourceFile->getParentModule();
 
-    return M.get<ModuleDecl *>();
+    return cast<ModuleDecl *>(M);
   }
 
 public:
@@ -295,12 +295,12 @@ class Verifier : public ASTWalker {
 #define EXPR(ID, PARENT) \
       case ExprKind::ID: \
         DISPATCH(ID);
-#define UNCHECKED_EXPR(ID, PARENT) \
-      case ExprKind::ID: \
-        assert((HadError || !M.is<SourceFile*>() || \
-                M.get<SourceFile*>()->ASTStage < SourceFile::TypeChecked) && \
-               #ID "in wrong phase");\
-        DISPATCH(ID);
+#define UNCHECKED_EXPR(ID, PARENT)                                             \
+  case ExprKind::ID:                                                           \
+    assert((HadError || !isa<SourceFile *>(M) ||                               \
+            cast<SourceFile *>(M)->ASTStage < SourceFile::TypeChecked) &&      \
+           #ID "in wrong phase");                                              \
+    DISPATCH(ID);
 #include "swift/AST/ExprNodes.def"
 #undef DISPATCH
       }
@@ -313,12 +313,12 @@ class Verifier : public ASTWalker {
 #define EXPR(ID, PARENT) \
       case ExprKind::ID: \
         DISPATCH(ID);
-#define UNCHECKED_EXPR(ID, PARENT) \
-      case ExprKind::ID: \
-        assert((HadError || !M.is<SourceFile*>() || \
-                M.get<SourceFile*>()->ASTStage < SourceFile::TypeChecked) && \
-               #ID "in wrong phase");\
-        DISPATCH(ID);
+#define UNCHECKED_EXPR(ID, PARENT)                                             \
+    case ExprKind::ID:                                                         \
+      assert((HadError || !isa<SourceFile *>(M) ||                             \
+              cast<SourceFile *>(M)->ASTStage < SourceFile::TypeChecked) &&    \
+             #ID "in wrong phase");                                            \
+      DISPATCH(ID);
 #include "swift/AST/ExprNodes.def"
 #undef DISPATCH
       }
@@ -723,13 +723,13 @@ class Verifier : public ASTWalker {
       Scopes.push_back(scope);
     }
     void popScope(DeclContext *scope) {
-      assert(Scopes.back().get<DeclContext*>() == scope);
+      assert(cast<DeclContext *>(Scopes.back()) == scope);
       assert(Generics.back() == scope);
       Scopes.pop_back();
       Generics.pop_back();
     }
     void popScope(BraceStmt *scope) {
-      assert(Scopes.back().get<BraceStmt*>() == scope);
+      assert(cast<BraceStmt *>(Scopes.back()) == scope);
       Scopes.pop_back();
     }
 
@@ -1097,9 +1097,15 @@ class Verifier : public ASTWalker {
     void verifyChecked(ReturnStmt *S) {
       auto func = Functions.back();
       Type resultType;
+      bool hasInOutResult = false;
+
       if (auto *FD = dyn_cast<FuncDecl>(func)) {
         resultType = FD->getResultInterfaceType();
         resultType = FD->mapTypeIntoContext(resultType);
+        hasInOutResult = FD->getInterfaceType()
+                             ->castTo<AnyFunctionType>()
+                             ->getExtInfo()
+                             .hasInOutResult();
       } else if (auto closure = dyn_cast<AbstractClosureExpr>(func)) {
         resultType = closure->getResultType();
       } else if (isa<ConstructorDecl>(func)) {
@@ -1112,6 +1118,9 @@ class Verifier : public ASTWalker {
         auto result = S->getResult();
         auto returnType = result->getType();
         // Make sure that the return has the same type as the function.
+        if (hasInOutResult) {
+          resultType = InOutType::get(resultType);
+        }
         checkSameType(resultType, returnType, "return type");
       } else {
         // Make sure that the function has a Void result type.
@@ -1345,7 +1354,7 @@ class Verifier : public ASTWalker {
     void verifyChecked(AbstractClosureExpr *E) {
       PrettyStackTraceExpr debugStack(Ctx, "verifying closure", E);
 
-      assert(Scopes.back().get<DeclContext*>() == E);
+      assert(cast<DeclContext *>(Scopes.back()) == E);
       assert(E->getParent()->isLocalContext() &&
              "closure expression was not in local context!");
 
@@ -1416,7 +1425,7 @@ class Verifier : public ASTWalker {
         abort();
       }
 
-      checkTrivialSubtype(srcTy, destTy, "MetatypeConversionExpr");
+      checkTrivialSubtype(E, srcTy, destTy, "MetatypeConversionExpr");
       verifyCheckedBase(E);
     }
     
@@ -1641,7 +1650,7 @@ class Verifier : public ASTWalker {
         abort();
       }
 
-      checkTrivialSubtype(srcTy, destTy, "DerivedToBaseExpr");
+      checkTrivialSubtype(E, srcTy, destTy, "DerivedToBaseExpr");
       verifyCheckedBase(E);
     }
 
@@ -1897,6 +1906,18 @@ class Verifier : public ASTWalker {
           continue;
         }
 
+        // If the argument is a concrete variadic expansion, let's check its
+        // every element.
+        if (auto *variadicExpansion = dyn_cast<VarargExpansionExpr>(subExpr)) {
+          if (auto *implicitArray =
+                  dyn_cast<ArrayExpr>(variadicExpansion->getSubExpr())) {
+            for (auto *element : implicitArray->getElements()) {
+              maybeRecordValidPointerConversionForArg(element);
+            }
+            return;
+          }
+        }
+
         break;
       }
 
@@ -2783,7 +2804,7 @@ class Verifier : public ASTWalker {
         // guarantee that all case label items bind corresponding patterns and
         // the case body var decls of a case stmt are created from the var decls
         // of the first case label items.
-        if (!caseStmt->hasBoundDecls()) {
+        if (!caseStmt->hasCaseBodyVariables()) {
           Out << "parent CaseStmt of VarDecl does not have any case body "
                  "decls?!\n";
           abort();
@@ -3590,12 +3611,14 @@ class Verifier : public ASTWalker {
       abort();
     }
 
-    void checkTrivialSubtype(Type srcTy, Type destTy, const char *what) {
+    void checkTrivialSubtype(Expr *E, Type srcTy, Type destTy,
+                             const char *what) {
       if (srcTy->isEqual(destTy)) return;
 
       if (auto srcMetatype = srcTy->getAs<AnyMetatypeType>()) {
         if (auto destMetatype = destTy->getAs<AnyMetatypeType>()) {
-          return checkTrivialSubtype(srcMetatype->getInstanceType(),
+          return checkTrivialSubtype(E,
+                                     srcMetatype->getInstanceType(),
                                      destMetatype->getInstanceType(),
                                      what);
         }
@@ -3625,6 +3648,7 @@ class Verifier : public ASTWalker {
       Out << " to ";
       destTy.print(Out);
       Out << "\n";
+      E->dump(Out);
       abort();
     }
 
diff --git a/lib/AST/ASTWalker.cpp b/lib/AST/ASTWalker.cpp
index 01d995e22156e..c72bdd2ee06ad 100644
--- a/lib/AST/ASTWalker.cpp
+++ b/lib/AST/ASTWalker.cpp
@@ -59,6 +59,7 @@
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/PrettyStackTrace.h"
 #include "swift/Basic/Assertions.h"
+
 using namespace swift;
 
 void ASTWalker::anchor() {}
@@ -120,6 +121,8 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
   [[nodiscard]]
   bool visit(Decl *D) {
     SetParentRAII SetParent(Walker, D);
+    if (visitDeclCommon(D))
+      return true;
     return inherited::visit(D);
   }
 
@@ -138,6 +141,40 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
   //                                 Decls
   //===--------------------------------------------------------------------===//
 
+  [[nodiscard]]
+  bool visitCustomAttr(CustomAttr *CA) {
+    auto *newTypeExpr = doIt(CA->getTypeExpr());
+    if (!newTypeExpr)
+      return true;
+
+    ASSERT(newTypeExpr == CA->getTypeExpr() &&
+           "Cannot change CustomAttr TypeExpr");
+
+    if (auto *args = CA->getArgs()) {
+      auto *newArgs = doIt(args);
+      if (!newArgs)
+        return true;
+
+      CA->setArgs(newArgs);
+    }
+    return false;
+  }
+
+  [[nodiscard]]
+  bool visitDeclCommon(Decl *D) {
+    if (Walker.shouldWalkIntoCustomAttrs()) {
+      for (auto *attr : D->getAttrs()) {
+        auto *CA = dyn_cast<CustomAttr>(attr);
+        if (!CA)
+          continue;
+
+        if (visitCustomAttr(CA))
+          return true;
+      }
+    }
+    return false;
+  }
+
   [[nodiscard]]
   bool visitGenericParamListIfNeeded(GenericContext *GC) {
     // Must check this first in case extensions have not been bound yet
@@ -165,6 +202,10 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
     return false;
   }
 
+  bool visitUsingDecl(UsingDecl *UD) {
+    return false;
+  }
+
   bool visitExtensionDecl(ExtensionDecl *ED) {
     if (auto *typeRepr = ED->getExtendedTypeRepr())
       if (doIt(typeRepr))
@@ -476,7 +517,7 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
         } else if (auto *stmt = expandedNode.dyn_cast<Stmt *>()) {
           alreadyFailed = doIt(stmt) == nullptr;
         } else {
-          auto decl = expandedNode.get<Decl *>();
+          auto decl = cast<Decl *>(expandedNode);
           if (!isa<VarDecl>(decl))
             alreadyFailed = doIt(decl);
         }
@@ -575,7 +616,15 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
     }                                                      \
   } while (false)
 
-  Expr *visitErrorExpr(ErrorExpr *E) { return E; }
+  Expr *visitErrorExpr(ErrorExpr *E) {
+    if (auto *origExpr = E->getOriginalExpr()) {
+      auto *newOrigExpr = doIt(origExpr);
+      if (!newOrigExpr)
+        return nullptr;
+      E->setOriginalExpr(newOrigExpr);
+    }
+    return E;
+  }
   Expr *visitCodeCompletionExpr(CodeCompletionExpr *E) {
     if (Expr *baseExpr = E->getBase()) {
       Expr *newBaseExpr = doIt(baseExpr);
@@ -1336,6 +1385,16 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
   Expr *visitKeyPathDotExpr(KeyPathDotExpr *E) { return E; }
 
   Expr *visitSingleValueStmtExpr(SingleValueStmtExpr *E) {
+    if (auto preamble = E->getForExpressionPreamble()) {
+      if (doIt(preamble->ForAccumulatorDecl)) {
+        return nullptr;
+      }
+
+      if (doIt(preamble->ForAccumulatorBinding)) {
+        return nullptr;
+      }
+    }
+
     if (auto *S = doIt(E->getStmt())) {
       E->setStmt(S);
     } else {
@@ -1421,6 +1480,10 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
   }
 
   Expr *visitTypeValueExpr(TypeValueExpr *E) {
+    if (auto *TR = E->getRepr()) {
+      if (doIt(TR))
+        return nullptr;
+    }
     return E;
   }
 
@@ -1864,7 +1927,7 @@ Stmt *Traversal::visitBraceStmt(BraceStmt *BS) {
       continue;
     }
 
-    auto *D = Elem.get<Decl*>();
+    auto *D = cast<Decl *>(Elem);
     if (doIt(D))
       return nullptr;
 
@@ -2214,10 +2277,25 @@ Pattern *Traversal::visitBoolPattern(BoolPattern *P) {
 
 #pragma mark Type representation traversal
 bool Traversal::visitErrorTypeRepr(ErrorTypeRepr *T) {
+  if (auto *originalExpr = T->getOriginalExpr()) {
+    auto *newExpr = doIt(originalExpr);
+    if (!newExpr)
+      return true;
+    T->setOriginalExpr(newExpr);
+  }
   return false;
 }
 
 bool Traversal::visitAttributedTypeRepr(AttributedTypeRepr *T) {
+  if (Walker.shouldWalkIntoCustomAttrs()) {
+    for (auto attr : T->getAttrs()) {
+      auto *CA = attr.dyn_cast<CustomAttr *>();
+      if (!CA)
+        continue;
+      if (visitCustomAttr(CA))
+        return true;
+    }
+  }
   return doIt(T->getTypeRepr());
 }
 
@@ -2324,6 +2402,10 @@ bool Traversal::visitSendingTypeRepr(SendingTypeRepr *T) {
   return doIt(T->getBase());
 }
 
+bool Traversal::visitCallerIsolatedTypeRepr(CallerIsolatedTypeRepr *T) {
+  return doIt(T->getBase());
+}
+
 bool Traversal::visitCompileTimeLiteralTypeRepr(CompileTimeLiteralTypeRepr *T) {
   return doIt(T->getBase());
 }
diff --git a/lib/AST/AccessNotes.cpp b/lib/AST/AccessNotes.cpp
index 9852876ad74a9..d2add08da323c 100644
--- a/lib/AST/AccessNotes.cpp
+++ b/lib/AST/AccessNotes.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -182,7 +182,7 @@ static void
 convertToErrorAndJoin(const llvm::SMDiagnostic &diag, void *ctxPtr) {
   ASTContext &ctx = *(ASTContext*)ctxPtr;
 
-  SourceLoc loc{diag.getLoc()};
+  auto loc = SourceLoc::getFromPointer(diag.getLoc().getPointer());
   assert(ctx.SourceMgr.isOwning(loc));
 
   switch (diag.getKind()) {
diff --git a/lib/AST/AccessRequests.cpp b/lib/AST/AccessRequests.cpp
index 996677cb07d01..9581435aa3bd6 100644
--- a/lib/AST/AccessRequests.cpp
+++ b/lib/AST/AccessRequests.cpp
@@ -62,11 +62,13 @@ AccessLevelRequest::evaluate(Evaluator &evaluator, ValueDecl *D) const {
     case AccessorKind::Address:
     case AccessorKind::Read:
     case AccessorKind::Read2:
+    case AccessorKind::Borrow:
       return storage->getFormalAccess();
     case AccessorKind::Set:
     case AccessorKind::MutableAddress:
     case AccessorKind::Modify:
     case AccessorKind::Modify2:
+    case AccessorKind::Mutate:
       return storage->getSetterFormalAccess();
     case AccessorKind::WillSet:
     case AccessorKind::DidSet:
diff --git a/lib/AST/ActorIsolation.cpp b/lib/AST/ActorIsolation.cpp
index 19c06555a08da..9c7f1816a86d4 100644
--- a/lib/AST/ActorIsolation.cpp
+++ b/lib/AST/ActorIsolation.cpp
@@ -23,23 +23,27 @@ ActorIsolation ActorIsolation::forMainActor(ASTContext &ctx) {
       ctx.getMainActorType()->mapTypeOutOfContext());
 }
 
+// These constructors are defined out-of-line so that including ActorIsolation.h
+// doesn't require a bunch of other headers to be included.
+
 ActorIsolation::ActorIsolation(Kind kind, NominalTypeDecl *actor,
-                               unsigned parameterIndex)
+                               EncodedParameterIndex parameterIndex)
     : actorInstance(actor), kind(kind), isolatedByPreconcurrency(false),
-      silParsed(false), parameterIndex(parameterIndex) {}
+      silParsed(false), encodedParameterIndex(parameterIndex.getOpaqueValue()) {}
 
 ActorIsolation::ActorIsolation(Kind kind, VarDecl *actor,
-                               unsigned parameterIndex)
+                               EncodedParameterIndex parameterIndex)
     : actorInstance(actor), kind(kind), isolatedByPreconcurrency(false),
-      silParsed(false), parameterIndex(parameterIndex) {}
+      silParsed(false), encodedParameterIndex(parameterIndex.getOpaqueValue()) {}
 
-ActorIsolation::ActorIsolation(Kind kind, Expr *actor, unsigned parameterIndex)
+ActorIsolation::ActorIsolation(Kind kind, Expr *actor,
+                               EncodedParameterIndex parameterIndex)
     : actorInstance(actor), kind(kind), isolatedByPreconcurrency(false),
-      silParsed(false), parameterIndex(parameterIndex) {}
+      silParsed(false), encodedParameterIndex(parameterIndex.getOpaqueValue()) {}
 
 ActorIsolation::ActorIsolation(Kind kind, Type globalActor)
     : globalActor(globalActor), kind(kind), isolatedByPreconcurrency(false),
-      silParsed(false), parameterIndex(0) {}
+      silParsed(false), encodedParameterIndex(0) {}
 
 ActorIsolation
 ActorIsolation::forActorInstanceParameter(Expr *actor,
@@ -61,31 +65,35 @@ ActorIsolation::forActorInstanceParameter(Expr *actor,
     if (auto globalActor = ctx.getProtocol(KnownProtocolKind::GlobalActor)) {
       auto conformance = checkConformance(baseType, globalActor);
       if (conformance &&
-          conformance.getWitnessByName(baseType, ctx.Id_shared) == declRef) {
+          conformance.getWitnessByName(ctx.Id_shared) == declRef) {
         return ActorIsolation::forGlobalActor(baseType);
       }
     }
   }
 
-  return ActorIsolation(ActorInstance, actor, parameterIndex + 1);
+  return ActorIsolation(ActorInstance, actor,
+                        EncodedParameterIndex::parameter(parameterIndex));
 }
 
 ActorIsolation ActorIsolation::forActorInstanceSelf(ValueDecl *decl) {
   if (auto *fn = dyn_cast<AbstractFunctionDecl>(decl))
-    return ActorIsolation(ActorInstance, fn->getImplicitSelfDecl(), 0);
+    return ActorIsolation(ActorInstance, fn->getImplicitSelfDecl(),
+                          EncodedParameterIndex::self());
 
   if (auto *storage = dyn_cast<AbstractStorageDecl>(decl)) {
     if (auto *fn = storage->getAccessor(AccessorKind::Get)) {
-      return ActorIsolation(ActorInstance, fn->getImplicitSelfDecl(), 0);
+      return ActorIsolation(ActorInstance, fn->getImplicitSelfDecl(),
+                            EncodedParameterIndex::self());
     }
   }
 
   auto *dc = decl->getDeclContext();
-  return ActorIsolation(ActorInstance, dc->getSelfNominalTypeDecl(), 0);
+  return ActorIsolation(ActorInstance, dc->getSelfNominalTypeDecl(),
+                        EncodedParameterIndex::self());
 }
 
 ActorIsolation ActorIsolation::forActorInstanceSelf(NominalTypeDecl *selfDecl) {
-  return ActorIsolation(ActorInstance, selfDecl, 0);
+  return ActorIsolation(ActorInstance, selfDecl, EncodedParameterIndex::self());
 }
 
 NominalTypeDecl *ActorIsolation::getActor() const {
@@ -113,7 +121,7 @@ NominalTypeDecl *ActorIsolation::getActor() const {
     return actorType->getReferenceStorageReferent()->getAnyActor();
   }
 
-  return actorInstance.get<NominalTypeDecl *>();
+  return cast<NominalTypeDecl *>(actorInstance);
 }
 
 VarDecl *ActorIsolation::getActorInstance() const {
@@ -183,6 +191,9 @@ bool ActorIsolation::isEqual(const ActorIsolation &lhs,
     auto *lhsActor = lhs.getActorInstance();
     auto *rhsActor = rhs.getActorInstance();
     if (lhsActor && rhsActor) {
+      if (lhsActor == rhsActor)
+        return true;
+
       // FIXME: This won't work for arbitrary isolated parameter captures.
       if ((lhsActor->isSelfParameter() && rhsActor->isSelfParamCapture()) ||
           (lhsActor->isSelfParamCapture() && rhsActor->isSelfParameter())) {
diff --git a/lib/AST/Attr.cpp b/lib/AST/Attr.cpp
index 61b992437d66c..ece312e6fa699 100644
--- a/lib/AST/Attr.cpp
+++ b/lib/AST/Attr.cpp
@@ -61,7 +61,7 @@ static_assert(IsTriviallyDestructible<DeclAttributes>::value,
                 DeclAttribute::APIBreakingToRemove | DeclAttribute::APIStableToRemove), \
                 #Name " needs to specify either APIBreakingToRemove or APIStableToRemove"); \
   static_assert(DeclAttribute::hasOneBehaviorFor##Id(DeclAttribute::InABIAttrMask), \
-                #Name " needs to specify exactly one of ForbiddenInABIAttr, UnconstrainedInABIAttr, EquivalentInABIAttr, InferredInABIAttr, or UnreachableInABIAttr");
+                #Name " needs to specify exactly one of ForbiddenInABIAttr, UnconstrainedInABIAttr, EquivalentInABIAttr, or UnreachableInABIAttr");
 #include "swift/AST/DeclAttr.def"
 
 #define TYPE_ATTR(_, Id)                                                       \
@@ -291,39 +291,12 @@ const char *IsolatedTypeAttr::getIsolationKindName(IsolationKind kind) {
 
 void IsolatedTypeAttr::printImpl(ASTPrinter &printer,
                                  const PrintOptions &options) const {
-  // Suppress the attribute if requested.
-  switch (getIsolationKind()) {
-  case IsolationKind::Dynamic:
-    if (options.SuppressIsolatedAny) return;
-    break;
-  }
-
   printer.callPrintStructurePre(PrintStructureKind::BuiltinAttribute);
   printer.printAttrName("@isolated");
   printer << "(" << getIsolationKindName() << ")";
   printer.printStructurePost(PrintStructureKind::BuiltinAttribute);
 }
 
-void ExecutionTypeAttr::printImpl(ASTPrinter &printer,
-                                  const PrintOptions &options) const {
-  if (options.SuppressExecutionAttribute)
-    return;
-
-  printer.callPrintStructurePre(PrintStructureKind::BuiltinAttribute);
-  printer.printAttrName("@execution");
-  printer << "(";
-  switch (getBehavior()) {
-  case ExecutionKind::Concurrent:
-    printer << "concurrent";
-    break;
-  case ExecutionKind::Caller:
-    printer << "caller";
-    break;
-  }
-  printer << ")";
-  printer.printStructurePost(PrintStructureKind::BuiltinAttribute);
-}
-
 /// Given a name like "inline", return the decl attribute ID that corresponds
 /// to it.  Note that this is a many-to-one mapping, and that the identifier
 /// passed in may only be the first portion of the attribute (e.g. in the case
@@ -441,8 +414,9 @@ DeclAttributes::getBackDeployed(const ASTContext &ctx,
 
     // We have an attribute that is active for the platform, but
     // is it more specific than our current best?
-    if (!bestAttr || inheritsAvailabilityFromPlatform(
-                         backDeployedAttr->Platform, bestAttr->Platform)) {
+    if (!bestAttr ||
+        inheritsAvailabilityFromPlatform(backDeployedAttr->getPlatform(),
+                                         bestAttr->getPlatform())) {
       bestAttr = backDeployedAttr;
     }
   }
@@ -577,8 +551,8 @@ static void printShortFormBackDeployed(ArrayRef<const DeclAttribute *> Attrs,
     if (!isFirst)
       Printer << ", ";
     auto *attr = cast<BackDeployedAttr>(DA);
-    Printer << platformString(attr->Platform) << " "
-            << attr->Version.getAsString();
+    Printer << platformString(attr->getPlatform()) << " "
+            << attr->getVersion().getAsString();
     isFirst = false;
   }
   Printer << ")";
@@ -791,9 +765,9 @@ static std::optional<PlatformKind> referencedPlatform(const DeclAttribute *attr,
     }
     return std::nullopt;
   case DeclAttrKind::BackDeployed:
-    return static_cast<const BackDeployedAttr *>(attr)->Platform;
+    return static_cast<const BackDeployedAttr *>(attr)->getPlatform();
   case DeclAttrKind::OriginallyDefinedIn:
-    return static_cast<const OriginallyDefinedInAttr *>(attr)->Platform;
+    return static_cast<const OriginallyDefinedInAttr *>(attr)->getPlatform();
   default:
     return std::nullopt;
   }
@@ -831,6 +805,7 @@ void DeclAttributes::print(ASTPrinter &Printer, const PrintOptions &Options,
   AttributeVector modifiers;
   bool libraryLevelAPI =
       D && D->getASTContext().LangOpts.LibraryLevel == LibraryLevel::API;
+  auto *SF = D ? D->getDeclContext()->getParentSourceFile() : nullptr;
 
   for (auto DA : llvm::reverse(FlattenedAttrs)) {
     // Don't skip implicit custom attributes. Custom attributes like global
@@ -875,6 +850,16 @@ void DeclAttributes::print(ASTPrinter &Printer, const PrintOptions &Options,
       if (!semanticAttr)
         continue;
 
+      // In the public interfaces of -library-level=api modules, skip @available
+      // attributes that refer to domains imported from @_spiOnly modules.
+      if (Options.printPublicInterface() && libraryLevelAPI) {
+        if (auto *domainDecl = semanticAttr->getDomain().getDecl()) {
+          if (SF->getRestrictedImportKind(domainDecl->getModuleContext()) ==
+              RestrictedImportKind::SPIOnly)
+            continue;
+        }
+      }
+
       if (isShortAvailable(*semanticAttr)) {
         if (semanticAttr->isSwiftLanguageModeSpecific())
           swiftVersionAvailableAttribute.emplace(*semanticAttr);
@@ -993,7 +978,7 @@ static void printAvailableAttr(const Decl *D, const SemanticAvailableAttr &Attr,
   // attributes that are universally unavailable in Swift, we must print them
   // as universally unavailable instead.
   // FIXME: Reconsider this, it's a weird special case.
-  if (Domain.isSwiftLanguage() && Attr.isUnconditionallyUnavailable())
+  if (Domain.isSwiftLanguageMode() && Attr.isUnconditionallyUnavailable())
     Printer << "*";
   else
     Printer << Domain.getNameForAttributePrinting();
@@ -1035,7 +1020,8 @@ static void printAvailableAttr(const Decl *D, const SemanticAvailableAttr &Attr,
   if (!Attr.getMessage().empty()) {
     Printer << ", message: ";
     Printer.printEscapedStringLiteral(Attr.getMessage());
-  } else if (Domain.isSwiftLanguage() && Attr.isUnconditionallyUnavailable())
+  } else if (Domain.isSwiftLanguageMode() &&
+             Attr.isUnconditionallyUnavailable())
     Printer << ", message: \"Not available in Swift\"";
 }
 
@@ -1114,7 +1100,7 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
   case DeclAttrKind::OriginallyDefinedIn: {
     auto Attr = cast<OriginallyDefinedInAttr>(this);
     auto Name = D->getDeclContext()->getParentModule()->getName().str();
-    if (Options.IsForSwiftInterface && Attr->ManglingModuleName == Name)
+    if (Options.IsForSwiftInterface && Attr->getManglingModuleName() == Name)
       return false;
     break;
   }
@@ -1153,7 +1139,18 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
       // Don't print into SIL. Necessary bits have already been generated.
       return false;
     } else {
-      Printer.printSimpleAttr(getAttrName(), /*needAt=*/true);
+      auto attrName = getAttrName();
+      if (getKind() == DeclAttrKind::Inline &&
+          cast<InlineAttr>(this)->getKind() == InlineKind::Always &&
+          Options.SuppressInlineAlways) {
+        attrName = "inline(__always)";
+        Printer.printSimpleAttr(attrName, /*needAt=*/true);
+        Printer << ' ';
+        // Add @inlinable
+        Printer.printSimpleAttr("inlinable", /*needAt=*/true);
+      } else {
+        Printer.printSimpleAttr(attrName, /*needAt=*/true);
+      }
     }
     return true;
 
@@ -1215,13 +1212,15 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
     Printer.printAttrName("@_originallyDefinedIn");
     Printer << "(module: ";
     auto Attr = cast<OriginallyDefinedInAttr>(this);
-    Printer << "\"" << Attr->ManglingModuleName;
-    ASSERT(!Attr->ManglingModuleName.empty());
-    ASSERT(!Attr->LinkerModuleName.empty());
-    if (Attr->LinkerModuleName != Attr->ManglingModuleName)
-      Printer << ";" << Attr->LinkerModuleName;
-    Printer << "\", " << platformString(Attr->Platform) << " " <<
-      Attr->MovedVersion.getAsString();
+    auto ManglingModuleName = Attr->getManglingModuleName();
+    auto LinkerModuleName = Attr->getLinkerModuleName();
+    Printer << "\"" << ManglingModuleName;
+    ASSERT(!ManglingModuleName.empty());
+    ASSERT(!LinkerModuleName.empty());
+    if (LinkerModuleName != ManglingModuleName)
+      Printer << ";" << LinkerModuleName;
+    Printer << "\", " << platformString(Attr->getPlatform()) << " "
+            << Attr->getMovedVersion().getAsString();
     Printer << ")";
     break;
   }
@@ -1259,9 +1258,17 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
     break;
   }
 
-  case DeclAttrKind::CDecl:
-    Printer << "@_cdecl(\"" << cast<CDeclAttr>(this)->Name << "\")";
+  case DeclAttrKind::CDecl: {
+    auto Attr = cast<CDeclAttr>(this);
+    if (Attr->Underscored)
+      Printer << "@_cdecl(\"" << cast<CDeclAttr>(this)->Name << "\")";
+    else {
+      Printer << "@c";
+      if (!Attr->Name.empty())
+        Printer << "(" << cast<CDeclAttr>(this)->Name << ")";
+    }
     break;
+  }
 
   case DeclAttrKind::Expose: {
     Printer.printAttrName("@_expose");
@@ -1273,6 +1280,9 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
     case ExposureKind::Cxx:
       Printer << "(Cxx";
       break;
+    case ExposureKind::NotCxx:
+      Printer << "(!Cxx";
+      break;
     }
     if (!cast<ExposeAttr>(this)->Name.empty())
       Printer << ", \"" << cast<ExposeAttr>(this)->Name << "\"";
@@ -1330,39 +1340,45 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
     break;
   }
 
+  case DeclAttrKind::Specialized:
   case DeclAttrKind::Specialize: {
-    auto *attr = cast<SpecializeAttr>(this);
+    auto *attr = cast<AbstractSpecializeAttr>(this);
     // Don't print the _specialize attribute if it is marked spi and we are
     // asked to skip SPI.
     if (Options.printPublicInterface() && !attr->getSPIGroups().empty())
       return false;
 
     Printer << "@" << getAttrName() << "(";
-    auto exported = attr->isExported() ? "true" : "false";
-    auto kind = attr->isPartialSpecialization() ? "partial" : "full";
-    auto target = attr->getTargetFunctionName();
-    Printer << "exported: "<<  exported << ", ";
-    for (auto id : attr->getSPIGroups()) {
-      Printer << "spi: " << id << ", ";
-    }
-    Printer << "kind: " << kind << ", ";
-    if (target)
-      Printer << "target: " << target << ", ";
-    SmallVector<SemanticAvailableAttr, 8> semanticAvailAttrs;
-    for (auto availAttr : attr->getAvailableAttrs()) {
-      if (auto semanticAttr = D->getSemanticAvailableAttr(availAttr))
-        semanticAvailAttrs.push_back(*semanticAttr);
-    }
 
-    if (!semanticAvailAttrs.empty()) {
-      Printer << "availability: ";
-      if (semanticAvailAttrs.size() == 1) {
-        printAvailableAttr(D, semanticAvailAttrs[0], Printer, Options);
-        Printer << "; ";
-      } else {
-        printShortFormAvailable(D, semanticAvailAttrs, Printer, Options,
-                                true /*forAtSpecialize*/);
-        Printer << "; ";
+    // The non-underscored @specialize attribute currently does not support
+    // parameters so lets not print them.
+    if (!attr->isPublic()) {
+      auto exported = attr->isExported() ? "true" : "false";
+      auto kind = attr->isPartialSpecialization() ? "partial" : "full";
+      auto target = attr->getTargetFunctionName();
+      Printer << "exported: "<<  exported << ", ";
+      for (auto id : attr->getSPIGroups()) {
+        Printer << "spi: " << id << ", ";
+      }
+      Printer << "kind: " << kind << ", ";
+      if (target)
+        Printer << "target: " << target << ", ";
+      SmallVector<SemanticAvailableAttr, 8> semanticAvailAttrs;
+      for (auto availAttr : attr->getAvailableAttrs()) {
+        if (auto semanticAttr = D->getSemanticAvailableAttr(availAttr))
+          semanticAvailAttrs.push_back(*semanticAttr);
+      }
+
+      if (!semanticAvailAttrs.empty()) {
+        Printer << "availability: ";
+        if (semanticAvailAttrs.size() == 1) {
+          printAvailableAttr(D, semanticAvailAttrs[0], Printer, Options);
+          Printer << "; ";
+        } else {
+          printShortFormAvailable(D, semanticAvailAttrs, Printer, Options,
+                                  true /*forAtSpecialize*/);
+          Printer << "; ";
+        }
       }
     }
     SmallVector<Requirement, 4> requirementsScratch;
@@ -1394,9 +1410,10 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
                     if (typeErased)
                       Printer << "@_noMetadata ";
                   }
-                  auto OptionsCopy = Options;
-                  OptionsCopy.PrintInternalLayoutName = typeErased;
-                  req.print(Printer, OptionsCopy);
+
+                  PrintOptions::OverrideScope scope(Options);
+                  OVERRIDE_PRINT_OPTION(scope, PrintInternalLayoutName, typeErased);
+                  req.print(Printer, Options);
                 },
                 [&] { Printer << ", "; });
 
@@ -1456,14 +1473,8 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
   }
 
   case DeclAttrKind::Custom: {
-    Printer.callPrintNamePre(PrintNameContext::Attribute);
-    Printer << "@";
     auto *attr = cast<CustomAttr>(this);
-    if (auto type = attr->getType())
-      type.print(Printer, Options);
-    else
-      attr->getTypeRepr()->print(Printer, Options);
-    Printer.printNamePost(PrintNameContext::Attribute);
+    attr->printCustomAttr(Printer, Options);
     break;
   }
 
@@ -1530,16 +1541,35 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
     Printer.printAttrName("@backDeployed");
     Printer << "(before: ";
     auto Attr = cast<BackDeployedAttr>(this);
-    Printer << platformString(Attr->Platform) << " " <<
-      Attr->Version.getAsString();
+    Printer << platformString(Attr->getPlatform()) << " "
+            << Attr->getVersion().getAsString();
     Printer << ")";
     break;
   }
 
   case DeclAttrKind::Nonisolated: {
     Printer.printAttrName("nonisolated");
-    if (cast<NonisolatedAttr>(this)->isUnsafe()) {
+    switch (cast<NonisolatedAttr>(this)->getModifier()) {
+    case NonIsolatedModifier::None:
+      break;
+    case NonIsolatedModifier::Unsafe:
       Printer << "(unsafe)";
+      break;
+    case NonIsolatedModifier::NonSending:
+      Printer << "(nonsending)";
+      break;
+    }
+    break;
+  }
+
+  case DeclAttrKind::InheritActorContext: {
+    Printer.printAttrName("@_inheritActorContext");
+    switch (cast<InheritActorContextAttr>(this)->getModifier()) {
+    case InheritActorContextModifier::None:
+      break;
+    case InheritActorContextModifier::Always:
+      Printer << "(always)";
+      break;
     }
     break;
   }
@@ -1684,7 +1714,11 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
 
   case DeclAttrKind::Lifetime: {
     auto *attr = cast<LifetimeAttr>(this);
-    Printer << attr->getLifetimeEntry()->getString();
+    if (!attr->isUnderscored() || Options.SuppressLifetimes) {
+      Printer << "@lifetime" << attr->getLifetimeEntry()->getString();
+    } else {
+      Printer << "@_lifetime" << attr->getLifetimeEntry()->getString();
+    }
     break;
   }
 
@@ -1698,7 +1732,7 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
                     ->getVarAtSimilarStructuralPosition(
                                       const_cast<VarDecl *>(cast<VarDecl>(D)));
     if (abiDecl) {
-      auto optionsCopy = Options;
+      PrintOptions::OverrideScope scope(Options);
 
       // Don't print any attributes marked with `ForbiddenInABIAttr`.
       // (Reminder: There is manual logic in `PrintAST::printAttributes()`
@@ -1710,26 +1744,26 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
           continue;
 
         if (attrKind == DeclAttrKind::AccessControl)
-          optionsCopy.PrintAccess = false;
+          OVERRIDE_PRINT_OPTION(scope, PrintAccess, false);
         else
-          optionsCopy.ExcludeAttrList.push_back(attrKind);
+          scope.addExcludedAttr(attrKind);
       }
 
-      abiDecl->print(Printer, optionsCopy);
+      abiDecl->print(Printer, Options);
     }
     Printer << ")";
 
     break;
   }
 
-  case DeclAttrKind::Execution: {
-    auto *attr = cast<ExecutionAttr>(this);
-    switch (attr->getBehavior()) {
-    case ExecutionKind::Concurrent:
-      Printer << "@execution(concurrent)";
+  case DeclAttrKind::Nonexhaustive: {
+    auto *attr = cast<NonexhaustiveAttr>(this);
+    Printer << "@nonexhaustive";
+    switch (attr->getMode()) {
+    case NonexhaustiveMode::Error:
       break;
-    case ExecutionKind::Caller:
-      Printer << "@execution(caller)";
+    case NonexhaustiveMode::Warning:
+      Printer << "(warn)";
       break;
     }
     break;
@@ -1809,7 +1843,9 @@ StringRef DeclAttribute::getAttrName() const {
   case DeclAttrKind::Alignment:
     return "_alignment";
   case DeclAttrKind::CDecl:
-    return "_cdecl";
+    if (cast<CDeclAttr>(this)->Underscored)
+      return "_cdecl";
+    return "c";
   case DeclAttrKind::SwiftNativeObjCRuntimeBase:
     return "_swift_native_objc_runtime_base";
   case DeclAttrKind::Semantics:
@@ -1835,8 +1871,10 @@ StringRef DeclAttribute::getAttrName() const {
     switch (cast<InlineAttr>(this)->getKind()) {
     case InlineKind::Never:
       return "inline(never)";
-    case InlineKind::Always:
+    case InlineKind::AlwaysUnderscored:
       return "inline(__always)";
+    case InlineKind::Always:
+      return "inline(always)";
     }
     llvm_unreachable("Invalid inline kind");
   }
@@ -1900,6 +1938,8 @@ StringRef DeclAttribute::getAttrName() const {
     return "<<ObjC bridged>>";
   case DeclAttrKind::SynthesizedProtocol:
     return "<<synthesized protocol>>";
+  case DeclAttrKind::Specialized:
+    return "specialized";
   case DeclAttrKind::Specialize:
     return "_specialize";
   case DeclAttrKind::StorageRestrictions:
@@ -1931,10 +1971,20 @@ StringRef DeclAttribute::getAttrName() const {
   case DeclAttrKind::Documentation:
     return "_documentation";
   case DeclAttrKind::Nonisolated:
-    if (cast<NonisolatedAttr>(this)->isUnsafe()) {
-        return "nonisolated(unsafe)";
-    } else {
-        return "nonisolated";
+    switch (cast<NonisolatedAttr>(this)->getModifier()) {
+    case NonIsolatedModifier::None:
+      return "nonisolated";
+    case NonIsolatedModifier::Unsafe:
+      return "nonisolated(unsafe)";
+    case NonIsolatedModifier::NonSending:
+      return "nonisolated(nonsending)";
+    }
+  case DeclAttrKind::InheritActorContext:
+    switch (cast<InheritActorContextAttr>(this)->getModifier()) {
+    case InheritActorContextModifier::None:
+      return "_inheritActorContext";
+    case InheritActorContextModifier::Always:
+      return "_inheritActorContext(always)";
     }
   case DeclAttrKind::MacroRole:
     switch (cast<MacroRoleAttr>(this)->getMacroSyntax()) {
@@ -1955,16 +2005,9 @@ StringRef DeclAttribute::getAttrName() const {
       return "_allowFeatureSuppression";
     }
   case DeclAttrKind::Lifetime:
-    return "lifetime";
-  case DeclAttrKind::Execution: {
-    switch (cast<ExecutionAttr>(this)->getBehavior()) {
-    case ExecutionKind::Concurrent:
-      return "execution(concurrent)";
-    case ExecutionKind::Caller:
-      return "execution(caller)";
-    }
-    llvm_unreachable("Invalid execution kind");
-  }
+    return cast<LifetimeAttr>(this)->isUnderscored() ? "_lifetime" : "lifetime";
+  case DeclAttrKind::Nonexhaustive:
+    return "nonexhaustive";
   }
   llvm_unreachable("bad DeclAttrKind");
 }
@@ -2287,7 +2330,7 @@ AvailableAttr *AvailableAttr::createUnavailableInSwift(ASTContext &C,
                                                        StringRef Message,
                                                        StringRef Rename) {
   return new (C) AvailableAttr(
-      SourceLoc(), SourceRange(), AvailabilityDomain::forSwiftLanguage(),
+      SourceLoc(), SourceRange(), AvailabilityDomain::forSwiftLanguageMode(),
       SourceLoc(), Kind::Unavailable, Message, Rename,
       /*Introduced=*/{}, SourceRange(), /*Deprecated=*/{}, SourceRange(),
       /*Obsoleted=*/{}, SourceRange(),
@@ -2299,7 +2342,7 @@ AvailableAttr *AvailableAttr::createSwiftLanguageModeVersioned(
     ASTContext &C, StringRef Message, StringRef Rename,
     llvm::VersionTuple Introduced, llvm::VersionTuple Obsoleted) {
   return new (C) AvailableAttr(
-      SourceLoc(), SourceRange(), AvailabilityDomain::forSwiftLanguage(),
+      SourceLoc(), SourceRange(), AvailabilityDomain::forSwiftLanguageMode(),
       SourceLoc(), Kind::Default, Message, Rename, Introduced, SourceRange(),
       /*Deprecated=*/{}, SourceRange(), Obsoleted, SourceRange(),
       /*Implicit=*/false,
@@ -2331,6 +2374,10 @@ AvailableAttr *AvailableAttr::createUnavailableInEmbedded(ASTContext &C,
       /*Implicit=*/false, /*IsSPI=*/false);
 }
 
+llvm::VersionTuple BackDeployedAttr::getVersion() const {
+  return canonicalizePlatformVersion(getPlatform(), getParsedVersion());
+}
+
 bool BackDeployedAttr::isActivePlatform(const ASTContext &ctx,
                                         bool forTargetVariant) const {
   return isPlatformActive(Platform, ctx.LangOpts, forTargetVariant);
@@ -2358,14 +2405,14 @@ bool AvailableAttr::isEquivalent(const AvailableAttr *other,
                 ==  attachedTo->getSemanticAvailableAttr(other)->getDomain();
 }
 
-static StringRef getManglingModuleName(StringRef OriginalModuleName) {
+static StringRef parseManglingModuleName(StringRef OriginalModuleName) {
   auto index = OriginalModuleName.find(";");
   return index == StringRef::npos
       ? OriginalModuleName
       : OriginalModuleName.slice(0, index);
 }
 
-static StringRef getLinkerModuleName(StringRef OriginalModuleName) {
+static StringRef parseLinkerModuleName(StringRef OriginalModuleName) {
   auto index = OriginalModuleName.find(";");
   return index == StringRef::npos
       ? OriginalModuleName
@@ -2373,22 +2420,22 @@ static StringRef getLinkerModuleName(StringRef OriginalModuleName) {
 }
 
 OriginallyDefinedInAttr::OriginallyDefinedInAttr(
-    SourceLoc AtLoc, SourceRange Range,
-    StringRef OriginalModuleName,
-    PlatformKind Platform,
-    const llvm::VersionTuple MovedVersion, bool Implicit)
-  : DeclAttribute(DeclAttrKind::OriginallyDefinedIn, AtLoc, Range,
-                  Implicit),
-    ManglingModuleName(getManglingModuleName(OriginalModuleName)),
-    LinkerModuleName(getLinkerModuleName(OriginalModuleName)),
-    Platform(Platform),
-    MovedVersion(MovedVersion) {}
+    SourceLoc AtLoc, SourceRange Range, StringRef OriginalModuleName,
+    PlatformKind Platform, const llvm::VersionTuple MovedVersion, bool Implicit)
+    : DeclAttribute(DeclAttrKind::OriginallyDefinedIn, AtLoc, Range, Implicit),
+      ManglingModuleName(parseManglingModuleName(OriginalModuleName)),
+      LinkerModuleName(parseLinkerModuleName(OriginalModuleName)),
+      Platform(Platform), MovedVersion(MovedVersion) {}
+
+llvm::VersionTuple OriginallyDefinedInAttr::getMovedVersion() const {
+  return canonicalizePlatformVersion(getPlatform(), getParsedMovedVersion());
+}
 
 std::optional<OriginallyDefinedInAttr::ActiveVersion>
 OriginallyDefinedInAttr::isActivePlatform(const ASTContext &ctx) const {
   OriginallyDefinedInAttr::ActiveVersion Result;
   Result.Platform = Platform;
-  Result.Version = MovedVersion;
+  Result.Version = getMovedVersion();
   Result.ManglingModuleName = ManglingModuleName;
   Result.LinkerModuleName = LinkerModuleName;
   if (isPlatformActive(Platform, ctx.LangOpts, /*TargetVariant*/false)) {
@@ -2452,31 +2499,32 @@ bool AvailableAttr::isNoAsync() const {
   llvm_unreachable("Unhandled AvailableAttr::Kind in switch.");
 }
 
-SpecializeAttr::SpecializeAttr(SourceLoc atLoc, SourceRange range,
-                               TrailingWhereClause *clause, bool exported,
+AbstractSpecializeAttr::AbstractSpecializeAttr(DeclAttrKind DK,
+                               SourceLoc atLoc, SourceRange range,
+                               TrailingWhereClause *clause,
+                               bool exported,
                                SpecializationKind kind,
                                GenericSignature specializedSignature,
                                DeclNameRef targetFunctionName,
                                ArrayRef<Identifier> spiGroups,
                                ArrayRef<AvailableAttr *> availableAttrs,
                                size_t typeErasedParamsCount)
-    : DeclAttribute(DeclAttrKind::Specialize, atLoc, range,
-                    /*Implicit=*/clause == nullptr),
+    : DeclAttribute(DK, atLoc, range, /*Implicit=*/clause == nullptr),
       trailingWhereClause(clause), specializedSignature(specializedSignature),
       targetFunctionName(targetFunctionName), numSPIGroups(spiGroups.size()),
       numAvailableAttrs(availableAttrs.size()),
       numTypeErasedParams(typeErasedParamsCount),
       typeErasedParamsInitialized(false) {
   std::uninitialized_copy(spiGroups.begin(), spiGroups.end(),
-                          getTrailingObjects<Identifier>());
+                          getSubclassTrailingObjects<Identifier>());
   std::uninitialized_copy(availableAttrs.begin(), availableAttrs.end(),
-                          getTrailingObjects<AvailableAttr *>());
+                          getSubclassTrailingObjects<AvailableAttr *>());
 
-  Bits.SpecializeAttr.exported = exported;
-  Bits.SpecializeAttr.kind = unsigned(kind);
+  Bits.AbstractSpecializeAttr.exported = exported;
+  Bits.AbstractSpecializeAttr.kind = unsigned(kind);
 }
 
-TrailingWhereClause *SpecializeAttr::getTrailingWhereClause() const {
+TrailingWhereClause *AbstractSpecializeAttr::getTrailingWhereClause() const {
   return trailingWhereClause;
 }
 
@@ -2489,15 +2537,13 @@ SpecializeAttr *SpecializeAttr::create(ASTContext &Ctx, SourceLoc atLoc,
                                        ArrayRef<AvailableAttr *> availableAttrs,
                                        GenericSignature specializedSignature) {
   size_t typeErasedParamsCount = 0;
-  if (Ctx.LangOpts.hasFeature(Feature::LayoutPrespecialization)) {
-    if (clause != nullptr) {
-      for (auto &req : clause->getRequirements()) {
-        if (req.getKind() == RequirementReprKind::LayoutConstraint) {
-          if (auto *attributedTy =
-                  dyn_cast<AttributedTypeRepr>(req.getSubjectRepr())) {
-            if (attributedTy->has(TypeAttrKind::NoMetadata)) {
-              typeErasedParamsCount += 1;
-            }
+  if (clause != nullptr) {
+    for (auto &req : clause->getRequirements()) {
+      if (req.getKind() == RequirementReprKind::LayoutConstraint) {
+        if (auto *attributedTy =
+                dyn_cast<AttributedTypeRepr>(req.getSubjectRepr())) {
+          if (attributedTy->has(TypeAttrKind::NoMetadata)) {
+            typeErasedParamsCount += 1;
           }
         }
       }
@@ -2523,8 +2569,8 @@ SpecializeAttr *SpecializeAttr::create(ASTContext &ctx, bool exported,
       spiGroups.size(), availableAttrs.size(), 0);
   void *mem = ctx.Allocate(size, alignof(SpecializeAttr));
   return new (mem) SpecializeAttr(
-      SourceLoc(), SourceRange(), nullptr, exported, kind, specializedSignature,
-      targetFunctionName, spiGroups, availableAttrs, 0);
+      SourceLoc(), SourceRange(), nullptr, exported, kind,
+      specializedSignature, targetFunctionName, spiGroups, availableAttrs, 0);
 }
 
 SpecializeAttr *SpecializeAttr::create(
@@ -2540,23 +2586,86 @@ SpecializeAttr *SpecializeAttr::create(
       SourceLoc(), SourceRange(), nullptr, exported, kind, specializedSignature,
       targetFunctionName, spiGroups, availableAttrs, typeErasedParams.size());
   attr->setTypeErasedParams(typeErasedParams);
-  attr->resolver = resolver;
-  attr->resolverContextData = data;
+  attr->setResolver(resolver, data);
   return attr;
 }
 
-ValueDecl * SpecializeAttr::getTargetFunctionDecl(const ValueDecl *onDecl) const {
+// @specialize
+//
+SpecializedAttr *SpecializedAttr::create(ASTContext &Ctx, SourceLoc atLoc,
+                                       SourceRange range,
+                                       TrailingWhereClause *clause,
+                                       bool exported, SpecializationKind kind,
+                                       DeclNameRef targetFunctionName,
+                                       ArrayRef<Identifier> spiGroups,
+                                       ArrayRef<AvailableAttr *> availableAttrs,
+                                       GenericSignature specializedSignature) {
+  size_t typeErasedParamsCount = 0;
+  if (clause != nullptr) {
+    for (auto &req : clause->getRequirements()) {
+      if (req.getKind() == RequirementReprKind::LayoutConstraint) {
+        if (auto *attributedTy =
+                dyn_cast<AttributedTypeRepr>(req.getSubjectRepr())) {
+          if (attributedTy->has(TypeAttrKind::NoMetadata)) {
+            typeErasedParamsCount += 1;
+          }
+        }
+      }
+    }
+  }
+
+  unsigned size = totalSizeToAlloc<Identifier, AvailableAttr *, Type>(
+      spiGroups.size(), availableAttrs.size(), typeErasedParamsCount);
+  void *mem = Ctx.Allocate(size, alignof(SpecializedAttr));
+
+  return new (mem)
+      SpecializedAttr(atLoc, range, clause, exported, kind, specializedSignature,
+                     targetFunctionName, spiGroups, availableAttrs, typeErasedParamsCount);
+}
+
+SpecializedAttr *SpecializedAttr::create(ASTContext &ctx, bool exported,
+                                       SpecializationKind kind,
+                                       ArrayRef<Identifier> spiGroups,
+                                       ArrayRef<AvailableAttr *> availableAttrs,
+                                       GenericSignature specializedSignature,
+                                       DeclNameRef targetFunctionName) {
+  unsigned size = totalSizeToAlloc<Identifier, AvailableAttr *, Type>(
+      spiGroups.size(), availableAttrs.size(), 0);
+  void *mem = ctx.Allocate(size, alignof(SpecializedAttr));
+  return new (mem) SpecializedAttr(
+      SourceLoc(), SourceRange(), nullptr, exported, kind,
+      specializedSignature, targetFunctionName, spiGroups, availableAttrs, 0);
+}
+
+SpecializedAttr *SpecializedAttr::create(
+    ASTContext &ctx, bool exported, SpecializationKind kind,
+    ArrayRef<Identifier> spiGroups, ArrayRef<AvailableAttr *> availableAttrs,
+    ArrayRef<Type> typeErasedParams, GenericSignature specializedSignature,
+    DeclNameRef targetFunctionName, LazyMemberLoader *resolver,
+    uint64_t data) {
+  unsigned size = totalSizeToAlloc<Identifier, AvailableAttr *, Type>(
+      spiGroups.size(), availableAttrs.size(), typeErasedParams.size());
+  void *mem = ctx.Allocate(size, alignof(SpecializedAttr));
+  auto *attr = new (mem) SpecializedAttr(
+      SourceLoc(), SourceRange(), nullptr, exported, kind, specializedSignature,
+      targetFunctionName, spiGroups, availableAttrs, typeErasedParams.size());
+  attr->setTypeErasedParams(typeErasedParams);
+  attr->setResolver(resolver, data);
+  return attr;
+}
+
+ValueDecl * AbstractSpecializeAttr::getTargetFunctionDecl(const ValueDecl *onDecl) const {
   return evaluateOrDefault(onDecl->getASTContext().evaluator,
                            SpecializeAttrTargetDeclRequest{
-                               onDecl, const_cast<SpecializeAttr *>(this)},
+                               onDecl, const_cast<AbstractSpecializeAttr *>(this)},
                            nullptr);
 }
 
-GenericSignature SpecializeAttr::getSpecializedSignature(
+GenericSignature AbstractSpecializeAttr::getSpecializedSignature(
     const AbstractFunctionDecl *onDecl) const {
   return evaluateOrDefault(onDecl->getASTContext().evaluator,
                            SerializeAttrGenericSignatureRequest{
-                               onDecl, const_cast<SpecializeAttr *>(this)},
+                               onDecl, const_cast<AbstractSpecializeAttr *>(this)},
                            nullptr);
 }
 
@@ -2595,7 +2704,7 @@ bool sameElements(ArrayRef<Element> first, ArrayRef<Element> second) {
   return sameElements(first, second, std::equal_to<Element>());
 }
 
-bool SpecializeAttr::isEquivalent(const SpecializeAttr *other,
+bool AbstractSpecializeAttr::isEquivalent(const AbstractSpecializeAttr *other,
                                   Decl *attachedTo) const {
   if (isExported() != other->isExported() ||
       getSpecializationKind() != other->getSpecializationKind() ||
@@ -2629,7 +2738,7 @@ SPIAccessControlAttr::SPIAccessControlAttr(SourceLoc atLoc, SourceRange range,
                     /*Implicit=*/false),
       numSPIGroups(spiGroups.size()) {
   std::uninitialized_copy(spiGroups.begin(), spiGroups.end(),
-                          getTrailingObjects<Identifier>());
+                          getTrailingObjects());
 }
 
 SPIAccessControlAttr *
@@ -2667,8 +2776,7 @@ DifferentiableAttr::DifferentiableAttr(bool implicit, SourceLoc atLoc,
   assert((diffKind != DifferentiabilityKind::Normal &&
           diffKind != DifferentiabilityKind::Forward) &&
          "'Normal' and 'Forward' are not supported");
-  std::copy(params.begin(), params.end(),
-            getTrailingObjects<ParsedAutoDiffParameter>());
+  std::copy(params.begin(), params.end(), getTrailingObjects());
 }
 
 DifferentiableAttr::DifferentiableAttr(Decl *original, bool implicit,
@@ -2770,8 +2878,7 @@ DerivativeAttr::DerivativeAttr(bool implicit, SourceLoc atLoc,
     : DeclAttribute(DeclAttrKind::Derivative, atLoc, baseRange, implicit),
       BaseTypeRepr(baseTypeRepr), OriginalFunctionName(std::move(originalName)),
       NumParsedParameters(params.size()) {
-  std::copy(params.begin(), params.end(),
-            getTrailingObjects<ParsedAutoDiffParameter>());
+  std::copy(params.begin(), params.end(), getTrailingObjects());
 }
 
 DerivativeAttr::DerivativeAttr(bool implicit, SourceLoc atLoc,
@@ -2837,8 +2944,7 @@ TransposeAttr::TransposeAttr(bool implicit, SourceLoc atLoc,
     : DeclAttribute(DeclAttrKind::Transpose, atLoc, baseRange, implicit),
       BaseTypeRepr(baseTypeRepr), OriginalFunctionName(std::move(originalName)),
       NumParsedParameters(params.size()) {
-  std::uninitialized_copy(params.begin(), params.end(),
-                          getTrailingObjects<ParsedAutoDiffParameter>());
+  std::uninitialized_copy(params.begin(), params.end(), getTrailingObjects());
 }
 
 TransposeAttr::TransposeAttr(bool implicit, SourceLoc atLoc,
@@ -2876,9 +2982,9 @@ StorageRestrictionsAttr::StorageRestrictionsAttr(
     : DeclAttribute(DeclAttrKind::StorageRestrictions, AtLoc, Range, Implicit),
       NumInitializes(initializes.size()), NumAccesses(accesses.size()) {
   std::uninitialized_copy(initializes.begin(), initializes.end(),
-                          getTrailingObjects<Identifier>());
+                          getTrailingObjects());
   std::uninitialized_copy(accesses.begin(), accesses.end(),
-                          getTrailingObjects<Identifier>() + NumInitializes);
+                          getTrailingObjects() + NumInitializes);
 }
 
 StorageRestrictionsAttr *
@@ -3138,7 +3244,7 @@ AllowFeatureSuppressionAttr::AllowFeatureSuppressionAttr(
   Bits.AllowFeatureSuppressionAttr.Inverted = inverted;
   Bits.AllowFeatureSuppressionAttr.NumFeatures = features.size();
   std::uninitialized_copy(features.begin(), features.end(),
-                          getTrailingObjects<Identifier>());
+                          getTrailingObjects());
 }
 
 AllowFeatureSuppressionAttr *AllowFeatureSuppressionAttr::create(
@@ -3160,8 +3266,15 @@ isEquivalent(const AllowFeatureSuppressionAttr *other, Decl *attachedTo) const {
 
 LifetimeAttr *LifetimeAttr::create(ASTContext &context, SourceLoc atLoc,
                                    SourceRange baseRange, bool implicit,
-                                   LifetimeEntry *entry) {
-  return new (context) LifetimeAttr(atLoc, baseRange, implicit, entry);
+                                   LifetimeEntry *entry, bool isUnderscored) {
+  return new (context)
+      LifetimeAttr(atLoc, baseRange, implicit, entry, isUnderscored);
+}
+
+std::string LifetimeAttr::getString() const {
+  return (isUnderscored() ? std::string("@_lifetime")
+                          : std::string("@lifetime")) +
+         getLifetimeEntry()->getString();
 }
 
 bool LifetimeAttr::isEquivalent(const LifetimeAttr *other,
diff --git a/lib/AST/Availability.cpp b/lib/AST/Availability.cpp
index 3f506a20f52d0..b6bd0ae6f6ae7 100644
--- a/lib/AST/Availability.cpp
+++ b/lib/AST/Availability.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -26,7 +26,7 @@
 // FIXME: [availability] Remove this when possible
 #include "swift/AST/DiagnosticsParse.h"
 #include "swift/AST/DiagnosticsSema.h"
-#include "swift/AST/PlatformKind.h"
+#include "swift/AST/PlatformKindUtils.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/AST/TypeWalker.h"
 #include "swift/AST/Types.h"
@@ -197,7 +197,7 @@ void AvailabilityInference::applyInferredAvailableAttrs(
 
       // Walk up the enclosing declaration hierarchy to make sure we aren't
       // missing any inherited attributes.
-      D = AvailabilityInference::parentDeclForInferredAvailability(D);
+      D = D->parentDeclForAvailability();
     } while (D);
   }
 
@@ -213,32 +213,31 @@ void AvailabilityInference::applyInferredAvailableAttrs(
 
 /// Returns the decl that should be considered the parent decl of the given decl
 /// when looking for inherited availability annotations.
-const Decl *
-AvailabilityInference::parentDeclForInferredAvailability(const Decl *D) {
-  if (auto *AD = dyn_cast<AccessorDecl>(D))
+const Decl *Decl::parentDeclForAvailability() const {
+  if (auto *AD = dyn_cast<AccessorDecl>(this))
     return AD->getStorage();
 
-  if (auto *ED = dyn_cast<ExtensionDecl>(D)) {
+  if (auto *ED = dyn_cast<ExtensionDecl>(this)) {
     if (auto *NTD = ED->getExtendedNominal())
       return NTD;
   }
 
-  if (auto *PBD = dyn_cast<PatternBindingDecl>(D)) {
+  if (auto *PBD = dyn_cast<PatternBindingDecl>(this)) {
     if (PBD->getNumPatternEntries() < 1)
       return nullptr;
 
     return PBD->getAnchoringVarDecl(0);
   }
 
-  if (auto *OTD = dyn_cast<OpaqueTypeDecl>(D))
+  if (auto *OTD = dyn_cast<OpaqueTypeDecl>(this))
     return OTD->getNamingDecl();
 
   // Clang decls may be inaccurately parented rdar://53956555
-  if (D->hasClangNode())
+  if (hasClangNode())
     return nullptr;
 
   // Availability is inherited from the enclosing context.
-  return D->getDeclContext()->getInnermostDeclarationDeclContext();
+  return getDeclContext()->getInnermostDeclarationDeclContext();
 }
 
 /// Returns true if the introduced version in \p newAttr should be used instead
@@ -297,18 +296,20 @@ bool AvailabilityInference::updateIntroducedAvailabilityDomainForFallback(
     const SemanticAvailableAttr &attr, const ASTContext &ctx,
     AvailabilityDomain &domain, llvm::VersionTuple &platformVer) {
   std::optional<llvm::VersionTuple> introducedVersion = attr.getIntroduced();
-  if (attr.getPlatform() == PlatformKind::iOS &&
-      introducedVersion.has_value() &&
-      isPlatformActive(PlatformKind::visionOS, ctx.LangOpts)) {
-    // We re-map the iOS introduced version to the corresponding visionOS version
-    auto potentiallyRemappedIntroducedVersion =
-        getRemappedIntroducedVersionForFallbackPlatform(ctx,
-                                                        *introducedVersion);
-    if (potentiallyRemappedIntroducedVersion.has_value()) {
-      domain = AvailabilityDomain::forPlatform(PlatformKind::visionOS);
-      platformVer = potentiallyRemappedIntroducedVersion.value();
-      return true;
-    }
+  if (!introducedVersion.has_value())
+    return false;
+
+  bool hasRemap = false;
+  auto remappedDomain = attr.getDomain().getRemappedDomain(ctx, hasRemap);
+  if (!hasRemap)
+    return false;
+
+  auto potentiallyRemappedIntroducedVersion =
+      getRemappedIntroducedVersionForFallbackPlatform(ctx, *introducedVersion);
+  if (potentiallyRemappedIntroducedVersion.has_value()) {
+    domain = remappedDomain;
+    platformVer = potentiallyRemappedIntroducedVersion.value();
+    return true;
   }
   return false;
 }
@@ -317,18 +318,21 @@ bool AvailabilityInference::updateDeprecatedAvailabilityDomainForFallback(
     const SemanticAvailableAttr &attr, const ASTContext &ctx,
     AvailabilityDomain &domain, llvm::VersionTuple &platformVer) {
   std::optional<llvm::VersionTuple> deprecatedVersion = attr.getDeprecated();
-  if (attr.getPlatform() == PlatformKind::iOS &&
-      deprecatedVersion.has_value() &&
-      isPlatformActive(PlatformKind::visionOS, ctx.LangOpts)) {
-    // We re-map the iOS deprecated version to the corresponding visionOS version
-    auto potentiallyRemappedDeprecatedVersion =
-        getRemappedDeprecatedObsoletedVersionForFallbackPlatform(
-            ctx, *deprecatedVersion);
-    if (potentiallyRemappedDeprecatedVersion.has_value()) {
-      domain = AvailabilityDomain::forPlatform(PlatformKind::visionOS);
-      platformVer = potentiallyRemappedDeprecatedVersion.value();
-      return true;
-    }
+  if (!deprecatedVersion.has_value())
+    return false;
+
+  bool hasRemap = false;
+  auto remappedDomain = attr.getDomain().getRemappedDomain(ctx, hasRemap);
+  if (!hasRemap)
+    return false;
+
+  auto potentiallyRemappedDeprecatedVersion =
+      getRemappedDeprecatedObsoletedVersionForFallbackPlatform(
+          ctx, *deprecatedVersion);
+  if (potentiallyRemappedDeprecatedVersion.has_value()) {
+    domain = remappedDomain;
+    platformVer = potentiallyRemappedDeprecatedVersion.value();
+    return true;
   }
   return false;
 }
@@ -337,44 +341,41 @@ bool AvailabilityInference::updateObsoletedAvailabilityDomainForFallback(
     const SemanticAvailableAttr &attr, const ASTContext &ctx,
     AvailabilityDomain &domain, llvm::VersionTuple &platformVer) {
   std::optional<llvm::VersionTuple> obsoletedVersion = attr.getObsoleted();
-  if (attr.getPlatform() == PlatformKind::iOS && obsoletedVersion.has_value() &&
-      isPlatformActive(PlatformKind::visionOS, ctx.LangOpts)) {
-    // We re-map the iOS obsoleted version to the corresponding visionOS version
-    auto potentiallyRemappedObsoletedVersion =
-        getRemappedDeprecatedObsoletedVersionForFallbackPlatform(
-            ctx, *obsoletedVersion);
-    if (potentiallyRemappedObsoletedVersion.has_value()) {
-      domain = AvailabilityDomain::forPlatform(PlatformKind::visionOS);
-      platformVer = potentiallyRemappedObsoletedVersion.value();
-      return true;
-    }
-  }
-  return false;
-}
+  if (!obsoletedVersion.has_value())
+    return false;
+
+  bool hasRemap = false;
+  auto remappedDomain = attr.getDomain().getRemappedDomain(ctx, hasRemap);
+  if (!hasRemap)
+    return false;
 
-void AvailabilityInference::updateAvailabilityDomainForFallback(
-    const SemanticAvailableAttr &attr, const ASTContext &Ctx,
-    AvailabilityDomain &domain) {
-  if (attr.getPlatform() == PlatformKind::iOS &&
-      isPlatformActive(PlatformKind::visionOS, Ctx.LangOpts)) {
-    domain = AvailabilityDomain::forPlatform(PlatformKind::visionOS);
+  auto potentiallyRemappedObsoletedVersion =
+      getRemappedDeprecatedObsoletedVersionForFallbackPlatform(
+          ctx, *obsoletedVersion);
+  if (potentiallyRemappedObsoletedVersion.has_value()) {
+    domain = remappedDomain;
+    platformVer = potentiallyRemappedObsoletedVersion.value();
+    return true;
   }
+  return false;
 }
 
 bool AvailabilityInference::updateBeforeAvailabilityDomainForFallback(
     const BackDeployedAttr *attr, const ASTContext &ctx,
     AvailabilityDomain &domain, llvm::VersionTuple &platformVer) {
-  auto beforeVersion = attr->Version;
-  if (attr->Platform == PlatformKind::iOS &&
-      isPlatformActive(PlatformKind::visionOS, ctx.LangOpts)) {
-    // We re-map the iOS before version to the corresponding visionOS version
-    auto PotentiallyRemappedIntroducedVersion =
-        getRemappedIntroducedVersionForFallbackPlatform(ctx, beforeVersion);
-    if (PotentiallyRemappedIntroducedVersion.has_value()) {
-      domain = AvailabilityDomain::forPlatform(PlatformKind::visionOS);
-      platformVer = PotentiallyRemappedIntroducedVersion.value();
-      return true;
-    }
+  bool hasRemap = false;
+  auto remappedDomain =
+      attr->getAvailabilityDomain().getRemappedDomain(ctx, hasRemap);
+  if (!hasRemap)
+    return false;
+
+  auto beforeVersion = attr->getVersion();
+  auto potentiallyRemappedIntroducedVersion =
+      getRemappedIntroducedVersionForFallbackPlatform(ctx, beforeVersion);
+  if (potentiallyRemappedIntroducedVersion.has_value()) {
+    domain = remappedDomain;
+    platformVer = potentiallyRemappedIntroducedVersion.value();
+    return true;
   }
   return false;
 }
@@ -406,7 +407,10 @@ AvailabilityInference::annotatedAvailableRange(const Decl *D) {
 }
 
 bool Decl::isAvailableAsSPI() const {
-  return AvailabilityInference::isAvailableAsSPI(this);
+  if (auto attr = getAvailableAttrForPlatformIntroduction())
+    return attr->isSPI();
+
+  return false;
 }
 
 SemanticAvailableAttributes
@@ -570,27 +574,6 @@ getRootTargetDomains(const ASTContext &ctx) {
   return domains;
 }
 
-static bool constraintIndicatesRuntimeUnavailability(
-    const AvailabilityConstraint &constraint, const ASTContext &ctx) {
-  std::optional<CustomAvailabilityDomain::Kind> customDomainKind;
-  if (auto customDomain = constraint.getDomain().getCustomDomain())
-    customDomainKind = customDomain->getKind();
-
-  switch (constraint.getReason()) {
-  case AvailabilityConstraint::Reason::UnconditionallyUnavailable:
-    if (customDomainKind)
-      return customDomainKind == CustomAvailabilityDomain::Kind::Enabled;
-    return true;
-  case AvailabilityConstraint::Reason::Obsoleted:
-  case AvailabilityConstraint::Reason::UnavailableForDeployment:
-    return false;
-  case AvailabilityConstraint::Reason::PotentiallyUnavailable:
-    if (customDomainKind)
-      return customDomainKind == CustomAvailabilityDomain::Kind::Disabled;
-    return false;
-  }
-}
-
 /// Returns true if a decl that is unavailable in the given domain must still be
 /// emitted to preserve load time ABI compatibility.
 static bool
@@ -629,10 +612,7 @@ computeDeclRuntimeAvailability(const Decl *decl) {
 
   // First, collect the unavailable domains from the constraints.
   llvm::SmallVector<AvailabilityDomain, 8> unavailableDomains;
-  for (auto constraint : constraints) {
-    if (constraintIndicatesRuntimeUnavailability(constraint, ctx))
-      unavailableDomains.push_back(constraint.getDomain());
-  }
+  getRuntimeUnavailableDomains(constraints, unavailableDomains, ctx);
 
   // Check whether there are any available attributes that would make the
   // decl available in descendants of the unavailable domains.
@@ -643,6 +623,10 @@ computeDeclRuntimeAvailability(const Decl *decl) {
       continue;
 
     llvm::erase_if(unavailableDomains, [domain](auto unavailableDomain) {
+      // Unavailability in '*' cannot be superseded by an @available attribute
+      // for a more specific availability domain.
+      if (unavailableDomain.isUniversal())
+        return false;
       return unavailableDomain.contains(domain);
     });
   }
@@ -656,6 +640,7 @@ computeDeclRuntimeAvailability(const Decl *decl) {
     if (!domain.isActive(ctx) && !isTargetDomain)
       continue;
 
+    // FIXME: [runtime availability] Update this?
     if (!domain.isRoot())
       continue;
 
@@ -694,10 +679,8 @@ DeclRuntimeAvailability
 DeclRuntimeAvailabilityRequest::evaluate(Evaluator &evaluator,
                                          const Decl *decl) const {
   auto inherited = DeclRuntimeAvailability::PotentiallyAvailable;
-  if (auto *parent =
-          AvailabilityInference::parentDeclForInferredAvailability(decl)) {
+  if (auto *parent = decl->parentDeclForAvailability())
     inherited = getDeclRuntimeAvailability(parent);
-  }
 
   // If the inherited runtime availability is already maximally unavailable
   // then skip computing unavailability for this declaration.
@@ -744,7 +727,7 @@ bool Decl::requiresUnavailableDeclABICompatibilityStubs() const {
 }
 
 AvailabilityRange AvailabilityInference::annotatedAvailableRangeForAttr(
-    const Decl *D, const SpecializeAttr *attr, ASTContext &ctx) {
+    const Decl *D, const AbstractSpecializeAttr *attr, ASTContext &ctx) {
   std::optional<SemanticAvailableAttr> bestAvailAttr;
 
   for (auto *availAttr : attr->getAvailableAttrs()) {
@@ -783,8 +766,7 @@ Decl::getAvailableAttrForPlatformIntroduction(bool checkExtension) const {
   if (!checkExtension)
     return std::nullopt;
 
-  if (auto parent =
-          AvailabilityInference::parentDeclForInferredAvailability(this)) {
+  if (auto parent = parentDeclForAvailability()) {
     if (auto *ED = dyn_cast<ExtensionDecl>(parent)) {
       if (auto attr = getDeclAvailableAttrForPlatformIntroduction(ED))
         return attr;
@@ -802,13 +784,6 @@ AvailabilityRange AvailabilityInference::availableRange(const Decl *D) {
   return AvailabilityRange::alwaysAvailable();
 }
 
-bool AvailabilityInference::isAvailableAsSPI(const Decl *D) {
-  if (auto attr = D->getAvailableAttrForPlatformIntroduction())
-    return attr->isSPI();
-
-  return false;
-}
-
 std::optional<SemanticAvailableAttr>
 SemanticAvailableAttrRequest::evaluate(swift::Evaluator &evaluator,
                                        const AvailableAttr *attr,
@@ -830,7 +805,10 @@ SemanticAvailableAttrRequest::evaluate(swift::Evaluator &evaluator,
 
   auto checkVersion = [&](std::optional<llvm::VersionTuple> version,
                           SourceRange sourceRange) {
-    if (version && !VersionRange::isValidVersion(*version)) {
+    if (!version)
+      return false;
+
+    if (!VersionRange::isValidVersion(*version)) {
       diags
           .diagnose(attrLoc, diag::availability_unsupported_version_number,
                     *version)
@@ -838,6 +816,16 @@ SemanticAvailableAttrRequest::evaluate(swift::Evaluator &evaluator,
       return true;
     }
 
+    // Warn if the version is not a valid one for the domain. For example, macOS
+    // 17 will never exist.
+    if (domain->isVersioned() && !domain->isVersionValid(*version)) {
+      diags
+          .diagnose(attrLoc,
+                    diag::availability_invalid_version_number_for_domain,
+                    *version, *domain)
+          .highlight(sourceRange);
+    }
+
     return false;
   };
 
@@ -868,7 +856,8 @@ SemanticAvailableAttrRequest::evaluate(swift::Evaluator &evaluator,
     return std::nullopt;
   }
 
-  if (domain->isSwiftLanguage() || domain->isPackageDescription()) {
+  if (domain->isSwiftLanguageMode() || domain->isPackageDescription() ||
+      domain->isSwiftRuntime()) {
     switch (attr->getKind()) {
     case AvailableAttr::Kind::Deprecated:
       diags.diagnose(attrLoc,
@@ -913,13 +902,19 @@ std::optional<llvm::VersionTuple> SemanticAvailableAttr::getIntroduced() const {
   return std::nullopt;
 }
 
-std::optional<AvailabilityRange>
-SemanticAvailableAttr::getIntroducedRange(const ASTContext &Ctx) const {
+std::optional<AvailabilityDomainAndRange>
+SemanticAvailableAttr::getIntroducedDomainAndRange(
+    const ASTContext &Ctx) const {
   auto *attr = getParsedAttr();
+  auto domain = getDomain();
+
+  if (domain.isUniversal())
+    return std::nullopt;
+
   if (!attr->getRawIntroduced().has_value()) {
     // For versioned domains, an "introduced:" version is always required to
     // indicate introduction.
-    if (getDomain().isVersioned())
+    if (domain.isVersioned())
       return std::nullopt;
 
     // For version-less domains, an attribute that does not indicate some other
@@ -927,7 +922,8 @@ SemanticAvailableAttr::getIntroducedRange(const ASTContext &Ctx) const {
     // the decl is available in all versions of the domain.
     switch (attr->getKind()) {
     case AvailableAttr::Kind::Default:
-      return AvailabilityRange::alwaysAvailable();
+      return AvailabilityDomainAndRange(domain.getRemappedDomain(Ctx),
+                                        AvailabilityRange::alwaysAvailable());
     case AvailableAttr::Kind::Deprecated:
     case AvailableAttr::Kind::Unavailable:
     case AvailableAttr::Kind::NoAsync:
@@ -936,13 +932,13 @@ SemanticAvailableAttr::getIntroducedRange(const ASTContext &Ctx) const {
   }
 
   llvm::VersionTuple introducedVersion = getIntroduced().value();
-  AvailabilityDomain unusedDomain;
   llvm::VersionTuple remappedVersion;
   if (AvailabilityInference::updateIntroducedAvailabilityDomainForFallback(
-          *this, Ctx, unusedDomain, remappedVersion))
+          *this, Ctx, domain, remappedVersion))
     introducedVersion = remappedVersion;
 
-  return AvailabilityRange{introducedVersion};
+  return AvailabilityDomainAndRange(domain,
+                                    AvailabilityRange{introducedVersion});
 }
 
 std::optional<llvm::VersionTuple> SemanticAvailableAttr::getDeprecated() const {
@@ -951,27 +947,31 @@ std::optional<llvm::VersionTuple> SemanticAvailableAttr::getDeprecated() const {
   return std::nullopt;
 }
 
-std::optional<AvailabilityRange>
-SemanticAvailableAttr::getDeprecatedRange(const ASTContext &Ctx) const {
+std::optional<AvailabilityDomainAndRange>
+SemanticAvailableAttr::getDeprecatedDomainAndRange(
+    const ASTContext &Ctx) const {
   auto *attr = getParsedAttr();
+  AvailabilityDomain domain = getDomain();
+
   if (!attr->getRawDeprecated().has_value()) {
     // Regardless of the whether the domain supports versions or not, an
     // unconditional deprecation attribute indicates the decl is always
     // deprecated.
     if (isUnconditionallyDeprecated())
-      return AvailabilityRange::alwaysAvailable();
+      return AvailabilityDomainAndRange(domain.getRemappedDomain(Ctx),
+                                        AvailabilityRange::alwaysAvailable());
 
     return std::nullopt;
   }
 
   llvm::VersionTuple deprecatedVersion = getDeprecated().value();
-  AvailabilityDomain unusedDomain;
   llvm::VersionTuple remappedVersion;
   if (AvailabilityInference::updateDeprecatedAvailabilityDomainForFallback(
-          *this, Ctx, unusedDomain, remappedVersion))
+          *this, Ctx, domain, remappedVersion))
     deprecatedVersion = remappedVersion;
 
-  return AvailabilityRange{deprecatedVersion};
+  return AvailabilityDomainAndRange(domain,
+                                    AvailabilityRange{deprecatedVersion});
 }
 
 std::optional<llvm::VersionTuple> SemanticAvailableAttr::getObsoleted() const {
@@ -980,22 +980,28 @@ std::optional<llvm::VersionTuple> SemanticAvailableAttr::getObsoleted() const {
   return std::nullopt;
 }
 
-std::optional<AvailabilityRange>
-SemanticAvailableAttr::getObsoletedRange(const ASTContext &Ctx) const {
+std::optional<AvailabilityDomainAndRange>
+SemanticAvailableAttr::getObsoletedDomainAndRange(const ASTContext &Ctx) const {
   auto *attr = getParsedAttr();
+  AvailabilityDomain domain = getDomain();
+
+  if (!attr->getRawObsoleted().has_value()) {
+    // An "unavailable" attribute effectively means obsolete in all versions.
+    if (attr->isUnconditionallyUnavailable())
+      return AvailabilityDomainAndRange(domain.getRemappedDomain(Ctx),
+                                        AvailabilityRange::alwaysAvailable());
 
-  // Obsoletion always requires a version.
-  if (!attr->getRawObsoleted().has_value())
     return std::nullopt;
+  }
 
   llvm::VersionTuple obsoletedVersion = getObsoleted().value();
-  AvailabilityDomain unusedDomain;
   llvm::VersionTuple remappedVersion;
   if (AvailabilityInference::updateObsoletedAvailabilityDomainForFallback(
-          *this, Ctx, unusedDomain, remappedVersion))
+          *this, Ctx, domain, remappedVersion))
     obsoletedVersion = remappedVersion;
 
-  return AvailabilityRange{obsoletedVersion};
+  return AvailabilityDomainAndRange(domain,
+                                    AvailabilityRange{obsoletedVersion});
 }
 
 namespace {
diff --git a/lib/AST/AvailabilityConstraint.cpp b/lib/AST/AvailabilityConstraint.cpp
index 9968cdcf2d34a..1eb15477f23c0 100644
--- a/lib/AST/AvailabilityConstraint.cpp
+++ b/lib/AST/AvailabilityConstraint.cpp
@@ -13,21 +13,19 @@
 #include "swift/AST/AvailabilityConstraint.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/AvailabilityContext.h"
-#include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/Decl.h"
 
 using namespace swift;
 
-std::optional<AvailabilityRange>
-AvailabilityConstraint::getPotentiallyUnavailableRange(
-    const ASTContext &ctx) const {
+AvailabilityDomainAndRange
+AvailabilityConstraint::getDomainAndRange(const ASTContext &ctx) const {
   switch (getReason()) {
-  case Reason::UnconditionallyUnavailable:
-  case Reason::Obsoleted:
-  case Reason::UnavailableForDeployment:
-    return std::nullopt;
-  case Reason::PotentiallyUnavailable:
-    return getAttr().getIntroducedRange(ctx);
+  case Reason::UnavailableUnconditionally:
+  case Reason::UnavailableObsolete:
+    return getAttr().getObsoletedDomainAndRange(ctx).value();
+  case Reason::UnavailableUnintroduced:
+  case Reason::Unintroduced:
+    return getAttr().getIntroducedDomainAndRange(ctx).value();
   }
 }
 
@@ -41,6 +39,32 @@ bool AvailabilityConstraint::isActiveForRuntimeQueries(
                                  /*forRuntimeQuery=*/true);
 }
 
+void AvailabilityConstraint::print(llvm::raw_ostream &os) const {
+  os << "AvailabilityConstraint(";
+  getAttr().getDomain().print(os);
+  os << ", ";
+
+  std::optional<llvm::VersionTuple> version;
+  switch (getReason()) {
+  case Reason::UnavailableUnconditionally:
+    os << "unavailable";
+    break;
+  case Reason::UnavailableObsolete:
+    os << "obsoleted";
+    version = getAttr().getObsoleted();
+    break;
+  case Reason::UnavailableUnintroduced:
+  case Reason::Unintroduced:
+    os << "introduced";
+    version = getAttr().getIntroduced();
+    break;
+  }
+
+  if (version)
+    os << ": " << *version;
+  os << ")";
+}
+
 static bool constraintIsStronger(const AvailabilityConstraint &lhs,
                                  const AvailabilityConstraint &rhs) {
   DEBUG_ASSERT(lhs.getDomain() == rhs.getDomain());
@@ -51,18 +75,20 @@ static bool constraintIsStronger(const AvailabilityConstraint &lhs,
     return lhs.getReason() < rhs.getReason();
 
   switch (lhs.getReason()) {
-  case AvailabilityConstraint::Reason::UnconditionallyUnavailable:
+  case AvailabilityConstraint::Reason::UnavailableUnconditionally:
     // Just keep the first.
     return false;
 
-  case AvailabilityConstraint::Reason::Obsoleted:
+  case AvailabilityConstraint::Reason::UnavailableObsolete:
     // Pick the larger obsoleted range.
-    return *lhs.getAttr().getObsoleted() < *rhs.getAttr().getObsoleted();
+    return lhs.getAttr().getObsoleted().value() <
+           rhs.getAttr().getObsoleted().value();
 
-  case AvailabilityConstraint::Reason::UnavailableForDeployment:
-  case AvailabilityConstraint::Reason::PotentiallyUnavailable:
+  case AvailabilityConstraint::Reason::UnavailableUnintroduced:
+  case AvailabilityConstraint::Reason::Unintroduced:
     // Pick the smaller introduced range.
-    return *lhs.getAttr().getIntroduced() > *rhs.getAttr().getIntroduced();
+    return lhs.getAttr().getIntroduced().value_or(llvm::VersionTuple()) >
+           rhs.getAttr().getIntroduced().value_or(llvm::VersionTuple());
   }
 }
 
@@ -113,25 +139,57 @@ DeclAvailabilityConstraints::getPrimaryConstraint() const {
   return result;
 }
 
+void DeclAvailabilityConstraints::print(llvm::raw_ostream &os) const {
+  os << "{\n";
+  llvm::interleave(
+      constraints,
+      [&os](const AvailabilityConstraint &constraint) {
+        os << "  " << constraint;
+      },
+      [&os] { os << ",\n"; });
+  os << "\n}";
+}
+
+static bool canIgnoreConstraintInUnavailableContexts(
+    const Decl *decl, const AvailabilityConstraint &constraint,
+    const AvailabilityConstraintFlags flags) {
+  auto domain = constraint.getDomain();
+
+  // Always reject uses of universally unavailable declarations, regardless
+  // of context, since there are no possible compilation configurations in
+  // which they are available. However, make an exception for types and
+  // conformances, which can sometimes be awkward to avoid references to.
+  if (!flags.contains(AvailabilityConstraintFlag::
+                      AllowUniversallyUnavailableInCompatibleContexts)) {
+    if (!isa<TypeDecl>(decl) && !isa<ExtensionDecl>(decl)) {
+      if (domain.isUniversal() || domain.isSwiftLanguageMode())
+        return false;
+    }
+  }
+
+  switch (constraint.getReason()) {
+  case AvailabilityConstraint::Reason::UnavailableUnconditionally:
+    return true;
+
+  case AvailabilityConstraint::Reason::Unintroduced:
+  case AvailabilityConstraint::Reason::UnavailableObsolete:
+  case AvailabilityConstraint::Reason::UnavailableUnintroduced:
+    return domain.isVersioned();
+  }
+}
+
 static bool
-isInsideCompatibleUnavailableDeclaration(const Decl *decl,
-                                         const SemanticAvailableAttr &attr,
-                                         const AvailabilityContext &context) {
+shouldIgnoreConstraintInContext(const Decl *decl,
+                                const AvailabilityConstraint &constraint,
+                                const AvailabilityContext &context,
+                                const AvailabilityConstraintFlags flags) {
   if (!context.isUnavailable())
     return false;
 
-  if (!attr.isUnconditionallyUnavailable())
+  if (!canIgnoreConstraintInUnavailableContexts(decl, constraint, flags))
     return false;
 
-  // Refuse calling universally unavailable functions from unavailable code,
-  // but allow the use of types.
-  auto domain = attr.getDomain();
-  if (!isa<TypeDecl>(decl) && !isa<ExtensionDecl>(decl)) {
-    if (domain.isUniversal() || domain.isSwiftLanguage())
-      return false;
-  }
-
-  return context.containsUnavailableDomain(domain);
+  return context.containsUnavailableDomain(constraint.getDomain());
 }
 
 /// Returns the `AvailabilityConstraint` that describes how \p attr restricts
@@ -142,34 +200,34 @@ getAvailabilityConstraintForAttr(const Decl *decl,
                                  const AvailabilityContext &context) {
   // Is the decl unconditionally unavailable?
   if (attr.isUnconditionallyUnavailable())
-    return AvailabilityConstraint::unconditionallyUnavailable(attr);
+    return AvailabilityConstraint::unavailableUnconditionally(attr);
 
   auto &ctx = decl->getASTContext();
   auto domain = attr.getDomain();
-  auto deploymentRange = domain.getDeploymentRange(ctx);
+  bool domainSupportsRefinement = domain.supportsContextRefinement();
 
-  // Is the decl obsoleted in the deployment context?
+  // Compute the available range in the given context. If there is no explicit
+  // range defined by the context, use the deployment range as fallback.
+  std::optional<AvailabilityRange> availableRange;
+  if (domainSupportsRefinement)
+    availableRange = context.getAvailabilityRange(domain, ctx);
+  if (!availableRange)
+    availableRange = domain.getDeploymentRange(ctx);
+
+  // Is the decl obsoleted in this context?
   if (auto obsoletedRange = attr.getObsoletedRange(ctx)) {
-    if (deploymentRange && deploymentRange->isContainedIn(*obsoletedRange))
-      return AvailabilityConstraint::obsoleted(attr);
+    if (availableRange && availableRange->isContainedIn(*obsoletedRange))
+      return AvailabilityConstraint::unavailableObsolete(attr);
   }
 
-  // Is the decl not yet introduced in the local context?
+  // Is the decl not yet introduced in this context?
   if (auto introducedRange = attr.getIntroducedRange(ctx)) {
-    if (domain.supportsContextRefinement()) {
-      auto availableRange = context.getAvailabilityRange(domain, ctx);
-      if (!availableRange || !availableRange->isContainedIn(*introducedRange))
-        return AvailabilityConstraint::potentiallyUnavailable(attr);
-
-      return std::nullopt;
-    }
-
-    // Is the decl not yet introduced in the deployment context?
-    if (deploymentRange && !deploymentRange->isContainedIn(*introducedRange))
-      return AvailabilityConstraint::unavailableForDeployment(attr);
+    if (!availableRange || !availableRange->isContainedIn(*introducedRange))
+      return domainSupportsRefinement
+                 ? AvailabilityConstraint::unintroduced(attr)
+                 : AvailabilityConstraint::unavailableUnintroduced(attr);
   }
 
-  // FIXME: [availability] Model deprecation as an availability constraint.
   return std::nullopt;
 }
 
@@ -218,8 +276,7 @@ static void getAvailabilityConstraintsForDecl(
   // declaration is unconditionally unavailable in a domain for which
   // the context is already unavailable.
   llvm::erase_if(constraints, [&](const AvailabilityConstraint &constraint) {
-    return isInsideCompatibleUnavailableDeclaration(decl, constraint.getAttr(),
-                                                    context);
+    return shouldIgnoreConstraintInContext(decl, constraint, context, flags);
   });
 }
 
@@ -250,9 +307,108 @@ swift::getAvailabilityConstraintsForDecl(const Decl *decl,
   if (decl->getClangNode())
     return constraints;
 
-  auto parent = AvailabilityInference::parentDeclForInferredAvailability(decl);
+  auto parent = decl->parentDeclForAvailability();
   if (auto extension = dyn_cast_or_null<ExtensionDecl>(parent))
     getAvailabilityConstraintsForDecl(constraints, extension, context, flags);
 
   return constraints;
 }
+
+std::optional<AvailabilityConstraint>
+swift::getAvailabilityConstraintForDeclInDomain(
+    const Decl *decl, const AvailabilityContext &context,
+    AvailabilityDomain domain, AvailabilityConstraintFlags flags) {
+  auto constraints = getAvailabilityConstraintsForDecl(decl, context, flags);
+  for (auto const &constraint : constraints) {
+    if (constraint.getDomain().isRelated(domain))
+      return constraint;
+  }
+
+  return std::nullopt;
+}
+
+/// Returns true if unsatisfied `@available(..., unavailable)` constraints for
+/// \p domain make code unreachable at runtime
+static bool
+domainCanBeUnconditionallyUnavailableAtRuntime(AvailabilityDomain domain,
+                                               const ASTContext &ctx) {
+  switch (domain.getKind()) {
+  case AvailabilityDomain::Kind::Universal:
+    return true;
+
+  case AvailabilityDomain::Kind::Platform:
+    if (ctx.LangOpts.TargetVariant &&
+        domain.isActive(ctx, /*forTargetVariant=*/true))
+      return true;
+    return domain.isActive(ctx);
+
+  case AvailabilityDomain::Kind::SwiftLanguageMode:
+  case AvailabilityDomain::Kind::SwiftRuntime:
+  case AvailabilityDomain::Kind::PackageDescription:
+    return false;
+
+  case AvailabilityDomain::Kind::Embedded:
+    return ctx.LangOpts.hasFeature(Feature::Embedded);
+
+  case AvailabilityDomain::Kind::Custom:
+    switch (domain.getCustomDomain()->getKind()) {
+    case CustomAvailabilityDomain::Kind::Enabled:
+    case CustomAvailabilityDomain::Kind::AlwaysEnabled:
+      return true;
+    case CustomAvailabilityDomain::Kind::Disabled:
+    case CustomAvailabilityDomain::Kind::Dynamic:
+      return false;
+    }
+  }
+}
+
+/// Returns true if unsatisfied introduction constraints for \p domain make
+/// code unreachable at runtime.
+static bool
+domainIsUnavailableAtRuntimeIfUnintroduced(AvailabilityDomain domain,
+                                           const ASTContext &ctx) {
+  switch (domain.getKind()) {
+  case AvailabilityDomain::Kind::Universal:
+  case AvailabilityDomain::Kind::Platform:
+  case AvailabilityDomain::Kind::SwiftLanguageMode:
+  case AvailabilityDomain::Kind::SwiftRuntime:
+  case AvailabilityDomain::Kind::PackageDescription:
+    return false;
+
+  case AvailabilityDomain::Kind::Embedded:
+    return !ctx.LangOpts.hasFeature(Feature::Embedded);
+
+  case AvailabilityDomain::Kind::Custom:
+    switch (domain.getCustomDomain()->getKind()) {
+    case CustomAvailabilityDomain::Kind::Enabled:
+    case CustomAvailabilityDomain::Kind::AlwaysEnabled:
+    case CustomAvailabilityDomain::Kind::Dynamic:
+      return false;
+    case CustomAvailabilityDomain::Kind::Disabled:
+      return true;
+    }
+  }
+}
+
+static bool constraintIndicatesRuntimeUnavailability(
+    const AvailabilityConstraint &constraint, const ASTContext &ctx) {
+  auto domain = constraint.getDomain();
+  switch (constraint.getReason()) {
+  case AvailabilityConstraint::Reason::UnavailableUnconditionally:
+    return domainCanBeUnconditionallyUnavailableAtRuntime(domain, ctx);
+  case AvailabilityConstraint::Reason::UnavailableObsolete:
+  case AvailabilityConstraint::Reason::UnavailableUnintroduced:
+    return false;
+  case AvailabilityConstraint::Reason::Unintroduced:
+    return domainIsUnavailableAtRuntimeIfUnintroduced(domain, ctx);
+  }
+}
+
+void swift::getRuntimeUnavailableDomains(
+    const DeclAvailabilityConstraints &constraints,
+    llvm::SmallVectorImpl<AvailabilityDomain> &domains, const ASTContext &ctx) {
+  for (auto constraint : constraints) {
+    if (constraintIndicatesRuntimeUnavailability(constraint, ctx))
+      domains.push_back(constraint.getDomain());
+  }
+}
diff --git a/lib/AST/AvailabilityContext.cpp b/lib/AST/AvailabilityContext.cpp
index f3d747cc630c2..327c74e420b2e 100644
--- a/lib/AST/AvailabilityContext.cpp
+++ b/lib/AST/AvailabilityContext.cpp
@@ -18,6 +18,7 @@
 #include "swift/AST/AvailabilityScope.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/Module.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/Basic/Assertions.h"
 
 using namespace swift;
@@ -155,6 +156,30 @@ AvailabilityContext::forDeploymentTarget(const ASTContext &ctx) {
       AvailabilityRange::forDeploymentTarget(ctx), ctx);
 }
 
+static AvailabilityContext
+contextForLocationInSourceFile(SourceLoc loc, SourceFile *sf,
+                               AvailabilityContext baseAvailability,
+                               const AvailabilityScope **refinedScope) {
+  if (!sf || loc.isInvalid())
+    return baseAvailability;
+
+  auto &ctx = sf->getASTContext();
+  auto *rootScope = AvailabilityScope::getOrBuildForSourceFile(*sf);
+  if (!rootScope)
+    return baseAvailability;
+
+  auto *scope = rootScope->findMostRefinedSubContext(loc, ctx);
+  if (!scope)
+    return baseAvailability;
+
+  if (refinedScope)
+    *refinedScope = scope;
+
+  auto availability = scope->getAvailabilityContext();
+  availability.constrainWithContext(baseAvailability, ctx);
+  return availability;
+}
+
 AvailabilityContext
 AvailabilityContext::forLocation(SourceLoc loc, const DeclContext *declContext,
                                  const AvailabilityScope **refinedScope) {
@@ -191,27 +216,38 @@ AvailabilityContext::forLocation(SourceLoc loc, const DeclContext *declContext,
     declContext = decl->getDeclContext();
   }
 
-  if (!sf || loc.isInvalid())
-    return baseAvailability;
+  return contextForLocationInSourceFile(loc, sf, baseAvailability,
+                                        refinedScope);
+}
 
-  auto *rootScope = AvailabilityScope::getOrBuildForSourceFile(*sf);
-  if (!rootScope)
-    return baseAvailability;
+AvailabilityContext AvailabilityContext::forDeclSignature(const Decl *decl) {
+  // For decls with valid source locations in source files, we can query the
+  // availability scope tree.
+  auto loc = decl->getLoc();
+  auto &ctx = decl->getASTContext();
+  auto availability = forInliningTarget(ctx);
 
-  auto *scope = rootScope->findMostRefinedSubContext(loc, ctx);
-  if (!scope)
-    return baseAvailability;
+  if (loc.isValid()) {
+    if (auto sf = decl->getDeclContext()
+                      ->getParentModule()
+                      ->getSourceFileContainingLocation(loc))
+      return contextForLocationInSourceFile(loc, sf, availability, nullptr);
+  }
 
-  if (refinedScope)
-    *refinedScope = scope;
+  // Otherwise, just walk the decl hierarchy to compute availability.
+  while (decl) {
+    availability.constrainWithDecl(decl);
+    decl = decl->parentDeclForAvailability();
+  }
 
-  auto availability = scope->getAvailabilityContext();
-  availability.constrainWithContext(baseAvailability, ctx);
   return availability;
 }
 
-AvailabilityContext AvailabilityContext::forDeclSignature(const Decl *decl) {
-  return forLocation(decl->getLoc(), decl->getInnermostDeclContext());
+AvailabilityContext
+AvailabilityContext::forAlwaysAvailable(const ASTContext &ctx) {
+  return AvailabilityContext(Storage::get(AvailabilityRange::alwaysAvailable(),
+                                          /*isDeprecated=*/false,
+                                          /*domainInfos=*/{}, ctx));
 }
 
 AvailabilityRange AvailabilityContext::getPlatformRange() const {
@@ -319,10 +355,13 @@ void AvailabilityContext::constrainWithDecl(const Decl *decl) {
 void AvailabilityContext::constrainWithDeclAndPlatformRange(
     const Decl *decl, const AvailabilityRange &otherPlatformRange) {
   auto &ctx = decl->getASTContext();
+
+  // Constrain the platform range first since this may have an effect on
+  // whether the decl is considered obsolete.
+  constrainWithPlatformRange(otherPlatformRange, ctx);
+
   bool isConstrained = false;
   auto platformRange = storage->platformRange;
-  isConstrained |= constrainRange(platformRange, otherPlatformRange);
-
   bool isDeprecated = storage->isDeprecated;
   isConstrained |= constrainBool(isDeprecated, decl->isDeprecated());
 
@@ -338,12 +377,12 @@ void AvailabilityContext::constrainWithDeclAndPlatformRange(
     auto attr = constraint.getAttr();
     auto domain = attr.getDomain();
     switch (constraint.getReason()) {
-    case AvailabilityConstraint::Reason::UnconditionallyUnavailable:
-    case AvailabilityConstraint::Reason::Obsoleted:
-    case AvailabilityConstraint::Reason::UnavailableForDeployment:
+    case AvailabilityConstraint::Reason::UnavailableUnconditionally:
+    case AvailabilityConstraint::Reason::UnavailableObsolete:
+    case AvailabilityConstraint::Reason::UnavailableUnintroduced:
       declDomainInfos.push_back(DomainInfo::unavailable(domain));
       break;
-    case AvailabilityConstraint::Reason::PotentiallyUnavailable:
+    case AvailabilityConstraint::Reason::Unintroduced:
       if (auto introducedRange = attr.getIntroducedRange(ctx)) {
         if (domain.isActivePlatform(ctx)) {
           isConstrained |= constrainRange(platformRange, *introducedRange);
diff --git a/lib/AST/AvailabilityDomain.cpp b/lib/AST/AvailabilityDomain.cpp
index 81d795f4a9086..d2924fb985b56 100644
--- a/lib/AST/AvailabilityDomain.cpp
+++ b/lib/AST/AvailabilityDomain.cpp
@@ -17,22 +17,105 @@
 #include "swift/AST/Module.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/ClangImporter/ClangImporter.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
 #include "llvm/ADT/StringSwitch.h"
 
 using namespace swift;
 
+CustomAvailabilityDomain::Kind
+getCustomDomainKind(clang::FeatureAvailKind featureAvailKind) {
+  switch (featureAvailKind) {
+  case clang::FeatureAvailKind::Available:
+    return CustomAvailabilityDomain::Kind::Enabled;
+  case clang::FeatureAvailKind::Unavailable:
+    return CustomAvailabilityDomain::Kind::Disabled;
+  case clang::FeatureAvailKind::Dynamic:
+    return CustomAvailabilityDomain::Kind::Dynamic;
+  case clang::FeatureAvailKind::AlwaysAvailable:
+    return CustomAvailabilityDomain::Kind::AlwaysEnabled;
+  default:
+    llvm::report_fatal_error("unexpected kind");
+  }
+}
+
+static const CustomAvailabilityDomain *
+customDomainForClangDecl(ValueDecl *decl) {
+  auto *clangDecl = decl->getClangDecl();
+  auto *varDecl = dyn_cast_or_null<clang::VarDecl>(clangDecl);
+  if (!varDecl)
+    return nullptr;
+
+  auto featureInfo = clangDecl->getASTContext().getFeatureAvailInfo(
+      const_cast<clang::VarDecl *>(varDecl));
+
+  // Ensure the decl actually represents an availability domain.
+  if (featureInfo.first.empty())
+    return nullptr;
+
+  // Check that the domain has a supported availability kind.
+  switch (featureInfo.second.Kind) {
+  case clang::FeatureAvailKind::Available:
+  case clang::FeatureAvailKind::Unavailable:
+  case clang::FeatureAvailKind::Dynamic:
+  case clang::FeatureAvailKind::AlwaysAvailable:
+    break;
+  default:
+    return nullptr;
+  }
+
+  auto &ctx = decl->getASTContext();
+  FuncDecl *predicate = nullptr;
+  if (featureInfo.second.Kind == clang::FeatureAvailKind::Dynamic)
+    predicate =
+        ctx.getClangModuleLoader()->getAvailabilityDomainPredicate(varDecl);
+
+  return CustomAvailabilityDomain::get(
+      featureInfo.first, getCustomDomainKind(featureInfo.second.Kind),
+      decl->getModuleContext(), decl, predicate, ctx);
+}
+
+std::optional<AvailabilityDomain>
+AvailabilityDomainForDeclRequest::evaluate(Evaluator &evaluator,
+                                           ValueDecl *decl) const {
+  if (!decl)
+    return std::nullopt;
+
+  if (decl->hasClangNode()) {
+    if (auto *customDomain = customDomainForClangDecl(decl))
+      return AvailabilityDomain::forCustom(customDomain);
+  } else {
+    // FIXME: [availability] Handle Swift availability domains decls.
+  }
+
+  return std::nullopt;
+}
+
+std::optional<AvailabilityDomain>
+AvailabilityDomain::forCustom(ValueDecl *decl) {
+  if (!decl)
+    return std::nullopt;
+
+  return evaluateOrDefault(decl->getASTContext().evaluator,
+                           AvailabilityDomainForDeclRequest{decl}, {});
+}
+
 std::optional<AvailabilityDomain>
 AvailabilityDomain::builtinDomainForString(StringRef string,
                                            const DeclContext *declContext) {
   // This parameter is used in downstream forks, do not remove.
   (void)declContext;
 
-  auto domain = llvm::StringSwitch<std::optional<AvailabilityDomain>>(string)
-                    .Case("*", AvailabilityDomain::forUniversal())
-                    .Case("swift", AvailabilityDomain::forSwiftLanguage())
-                    .Case("_PackageDescription",
-                          AvailabilityDomain::forPackageDescription())
-                    .Default(std::nullopt);
+  auto domain =
+      llvm::StringSwitch<std::optional<AvailabilityDomain>>(string)
+          .Case("*", AvailabilityDomain::forUniversal())
+          .Case("swift", AvailabilityDomain::forSwiftLanguageMode())
+          .Case("SwiftLanguageMode", AvailabilityDomain::forSwiftLanguageMode())
+          .Case("Swift", AvailabilityDomain::forSwiftRuntime())
+          .Case("_PackageDescription",
+                AvailabilityDomain::forPackageDescription())
+          .Default(std::nullopt);
 
   if (domain)
     return domain;
@@ -48,7 +131,8 @@ bool AvailabilityDomain::isVersioned() const {
   case Kind::Universal:
   case Kind::Embedded:
     return false;
-  case Kind::SwiftLanguage:
+  case Kind::SwiftLanguageMode:
+  case Kind::SwiftRuntime:
   case Kind::PackageDescription:
   case Kind::Platform:
     return true;
@@ -58,13 +142,40 @@ bool AvailabilityDomain::isVersioned() const {
   }
 }
 
+bool AvailabilityDomain::isVersionValid(
+    const llvm::VersionTuple &version) const {
+  ASSERT(isVersioned());
+
+  switch (getKind()) {
+  case Kind::Universal:
+  case Kind::Embedded:
+    llvm_unreachable("unexpected domain kind");
+  case Kind::SwiftLanguageMode:
+  case Kind::PackageDescription:
+    return true;
+  case Kind::SwiftRuntime:
+    // Swift 5.0 is the first ABI stable Swift runtime version.
+    if (version.getMajor() < 5)
+      return false;
+    return true;
+
+  case Kind::Platform:
+    if (auto osType = tripleOSTypeForPlatform(getPlatformKind()))
+      return llvm::Triple::isValidVersionForOS(*osType, version);
+    return true;
+  case Kind::Custom:
+    return true;
+  }
+}
+
 bool AvailabilityDomain::supportsContextRefinement() const {
   switch (getKind()) {
   case Kind::Universal:
   case Kind::Embedded:
-  case Kind::SwiftLanguage:
+  case Kind::SwiftLanguageMode:
   case Kind::PackageDescription:
     return false;
+  case Kind::SwiftRuntime:
   case Kind::Platform:
   case Kind::Custom:
     return true;
@@ -75,24 +186,28 @@ bool AvailabilityDomain::supportsQueries() const {
   switch (getKind()) {
   case Kind::Universal:
   case Kind::Embedded:
-  case Kind::SwiftLanguage:
+  case Kind::SwiftLanguageMode:
   case Kind::PackageDescription:
     return false;
+  case Kind::SwiftRuntime:
   case Kind::Platform:
   case Kind::Custom:
     return true;
   }
 }
 
-bool AvailabilityDomain::isActive(const ASTContext &ctx) const {
+bool AvailabilityDomain::isActive(const ASTContext &ctx,
+                                  bool forTargetVariant) const {
   switch (getKind()) {
   case Kind::Universal:
-  case Kind::SwiftLanguage:
+  case Kind::SwiftLanguageMode:
   case Kind::PackageDescription:
   case Kind::Embedded:
     return true;
+  case Kind::SwiftRuntime:
+    return ctx.LangOpts.hasFeature(Feature::SwiftRuntimeAvailability);
   case Kind::Platform:
-    return isPlatformActive(getPlatformKind(), ctx.LangOpts);
+    return isPlatformActive(getPlatformKind(), ctx.LangOpts, forTargetVariant);
   case Kind::Custom:
     // For now, custom domains are always active but it's conceivable that in
     // the future someone might want to define a domain but leave it inactive.
@@ -100,11 +215,30 @@ bool AvailabilityDomain::isActive(const ASTContext &ctx) const {
   }
 }
 
-bool AvailabilityDomain::isActivePlatform(const ASTContext &ctx) const {
+bool AvailabilityDomain::isActivePlatform(const ASTContext &ctx,
+                                          bool forTargetVariant) const {
   if (!isPlatform())
     return false;
 
-  return isActive(ctx);
+  return isActive(ctx, forTargetVariant);
+}
+
+bool AvailabilityDomain::mustBeSpecifiedAlone() const {
+  switch (getKind()) {
+  case Kind::Universal:
+  case Kind::SwiftLanguageMode:
+  case Kind::PackageDescription:
+  case Kind::Embedded:
+  case Kind::Custom:
+    return true;
+  case Kind::SwiftRuntime:
+  case Kind::Platform:
+    // Platform and Swift runtime availability specifications can appear
+    // together, e.g. `@available(Swift 6, macOS 15, iOS 18, *)`.
+    // If there are ever multiple disjoint groups of domains that may be
+    // specified together in the future, this will need to be re-designed.
+    return false;
+  }
 }
 
 static std::optional<llvm::VersionTuple>
@@ -114,10 +248,14 @@ getDeploymentVersion(const AvailabilityDomain &domain, const ASTContext &ctx) {
   case AvailabilityDomain::Kind::Embedded:
   case AvailabilityDomain::Kind::Custom:
     return std::nullopt;
-  case AvailabilityDomain::Kind::SwiftLanguage:
+  case AvailabilityDomain::Kind::SwiftLanguageMode:
     return ctx.LangOpts.EffectiveLanguageVersion;
   case AvailabilityDomain::Kind::PackageDescription:
     return ctx.LangOpts.PackageDescriptionVersion;
+  case AvailabilityDomain::Kind::SwiftRuntime:
+    if (!ctx.LangOpts.hasFeature(Feature::SwiftRuntimeAvailability))
+      return std::nullopt;
+    return ctx.LangOpts.MinSwiftRuntimeVersion;
   case AvailabilityDomain::Kind::Platform:
     if (domain.isActive(ctx))
       return ctx.LangOpts.getMinPlatformVersion();
@@ -127,8 +265,23 @@ getDeploymentVersion(const AvailabilityDomain &domain, const ASTContext &ctx) {
 
 std::optional<AvailabilityRange>
 AvailabilityDomain::getDeploymentRange(const ASTContext &ctx) const {
-  if (auto version = getDeploymentVersion(*this, ctx))
-    return AvailabilityRange{*version};
+  if (isVersioned()) {
+    if (auto version = getDeploymentVersion(*this, ctx))
+      return AvailabilityRange{*version};
+
+    return std::nullopt;
+  }
+
+  if (auto customDomain = getCustomDomain()) {
+    switch (customDomain->getKind()) {
+    case CustomAvailabilityDomain::Kind::AlwaysEnabled:
+      return AvailabilityRange::alwaysAvailable();
+    case CustomAvailabilityDomain::Kind::Enabled:
+    case CustomAvailabilityDomain::Kind::Disabled:
+    case CustomAvailabilityDomain::Kind::Dynamic:
+      return std::nullopt;
+    }
+  }
   return std::nullopt;
 }
 
@@ -136,7 +289,10 @@ llvm::StringRef AvailabilityDomain::getNameForDiagnostics() const {
   switch (getKind()) {
   case Kind::Universal:
     return "*";
-  case Kind::SwiftLanguage:
+  case Kind::SwiftLanguageMode:
+    // FIXME: [runtime availability] Render language mode diags differently.
+    return "Swift";
+  case Kind::SwiftRuntime:
     return "Swift";
   case Kind::PackageDescription:
     return "PackageDescription";
@@ -153,8 +309,10 @@ llvm::StringRef AvailabilityDomain::getNameForAttributePrinting() const {
   switch (getKind()) {
   case Kind::Universal:
     return "*";
-  case Kind::SwiftLanguage:
+  case Kind::SwiftLanguageMode:
     return "swift";
+  case Kind::SwiftRuntime:
+    return "Swift";
   case Kind::PackageDescription:
     return "_PackageDescription";
   case Kind::Embedded:
@@ -166,6 +324,13 @@ llvm::StringRef AvailabilityDomain::getNameForAttributePrinting() const {
   }
 }
 
+ValueDecl *AvailabilityDomain::getDecl() const {
+  if (auto *customDomain = getCustomDomain())
+    return customDomain->getDecl();
+
+  return nullptr;
+}
+
 ModuleDecl *AvailabilityDomain::getModule() const {
   if (auto customDomain = getCustomDomain())
     return customDomain->getModule();
@@ -177,11 +342,13 @@ bool AvailabilityDomain::contains(const AvailabilityDomain &other) const {
   switch (getKind()) {
   case Kind::Universal:
     return true;
-  case Kind::SwiftLanguage:
+  case Kind::SwiftLanguageMode:
   case Kind::PackageDescription:
   case Kind::Embedded:
   case Kind::Custom:
     return other == *this;
+  case Kind::SwiftRuntime:
+    return other.isPlatform() || other == *this;
   case Kind::Platform:
     if (getPlatformKind() == other.getPlatformKind())
       return true;
@@ -194,7 +361,8 @@ bool AvailabilityDomain::isRoot() const {
   switch (getKind()) {
   case AvailabilityDomain::Kind::Universal:
   case AvailabilityDomain::Kind::Embedded:
-  case AvailabilityDomain::Kind::SwiftLanguage:
+  case AvailabilityDomain::Kind::SwiftLanguageMode:
+  case AvailabilityDomain::Kind::SwiftRuntime:
   case AvailabilityDomain::Kind::PackageDescription:
     return true;
   case AvailabilityDomain::Kind::Platform:
@@ -221,6 +389,57 @@ AvailabilityDomain AvailabilityDomain::getRootDomain() const {
   return *this;
 }
 
+const AvailabilityDomain
+AvailabilityDomain::getRemappedDomain(const ASTContext &ctx,
+                                      bool &didRemap) const {
+  if (getPlatformKind() == PlatformKind::iOS &&
+      isPlatformActive(PlatformKind::visionOS, ctx.LangOpts)) {
+    didRemap = true;
+    return AvailabilityDomain::forPlatform(PlatformKind::visionOS);
+  }
+
+  return *this;
+}
+
+bool IsCustomAvailabilityDomainPermanentlyEnabled::evaluate(
+    Evaluator &evaluator, const CustomAvailabilityDomain *customDomain) const {
+  switch (customDomain->getKind()) {
+  case CustomAvailabilityDomain::Kind::Enabled:
+  case CustomAvailabilityDomain::Kind::Disabled:
+  case CustomAvailabilityDomain::Kind::Dynamic:
+    return false;
+
+  case CustomAvailabilityDomain::Kind::AlwaysEnabled:
+    break;
+  }
+
+  auto *domainDecl = customDomain->getDecl();
+  if (!domainDecl)
+    return false;
+
+  if (auto deprecatedAttr = domainDecl->getDeprecatedAttr()) {
+    if (deprecatedAttr->getDomain().isUniversal())
+      return true;
+  }
+
+  if (auto unavailableAttr = domainDecl->getUnavailableAttr()) {
+    if (unavailableAttr->getDomain().isUniversal())
+      return true;
+  }
+
+  return false;
+}
+
+bool AvailabilityDomain::isPermanentlyAlwaysEnabled() const {
+  if (auto *customDomain = getCustomDomain()) {
+    if (auto *domainDecl = customDomain->getDecl())
+      return evaluateOrDefault(
+          domainDecl->getASTContext().evaluator,
+          IsCustomAvailabilityDomainPermanentlyEnabled{customDomain}, false);
+  }
+  return false;
+}
+
 void AvailabilityDomain::print(llvm::raw_ostream &os) const {
   os << getNameForAttributePrinting();
 }
@@ -228,7 +447,8 @@ void AvailabilityDomain::print(llvm::raw_ostream &os) const {
 AvailabilityDomain AvailabilityDomain::copy(ASTContext &ctx) const {
   switch (getKind()) {
   case Kind::Universal:
-  case Kind::SwiftLanguage:
+  case Kind::SwiftLanguageMode:
+  case Kind::SwiftRuntime:
   case Kind::PackageDescription:
   case Kind::Embedded:
   case Kind::Platform:
@@ -250,7 +470,8 @@ bool StableAvailabilityDomainComparator::operator()(
 
   switch (lhsKind) {
   case AvailabilityDomain::Kind::Universal:
-  case AvailabilityDomain::Kind::SwiftLanguage:
+  case AvailabilityDomain::Kind::SwiftLanguageMode:
+  case AvailabilityDomain::Kind::SwiftRuntime:
   case AvailabilityDomain::Kind::PackageDescription:
   case AvailabilityDomain::Kind::Embedded:
     return false;
@@ -268,19 +489,22 @@ bool StableAvailabilityDomainComparator::operator()(
   }
 }
 
-CustomAvailabilityDomain::CustomAvailabilityDomain(Identifier name,
-                                                   ModuleDecl *mod, Kind kind)
-    : name(name), kind(kind), mod(mod) {
+CustomAvailabilityDomain::CustomAvailabilityDomain(Identifier name, Kind kind,
+                                                   ModuleDecl *mod,
+                                                   ValueDecl *decl,
+                                                   FuncDecl *predicateFunc)
+    : name(name), mod(mod), decl(decl), predicateFunc(predicateFunc),
+      kind(kind) {
   ASSERT(!name.empty());
   ASSERT(mod);
+  if (predicateFunc)
+    ASSERT(kind == Kind::Dynamic);
 }
 
 void CustomAvailabilityDomain::Profile(llvm::FoldingSetNodeID &ID,
-                                       Identifier name, ModuleDecl *mod,
-                                       Kind kind) {
+                                       Identifier name, ModuleDecl *mod) {
   ID.AddPointer(name.getAsOpaquePointer());
   ID.AddPointer(mod);
-  ID.AddInteger(static_cast<unsigned>(kind));
 }
 
 std::optional<AvailabilityDomain>
@@ -300,28 +524,68 @@ AvailabilityDomainOrIdentifier::lookUpInDeclContext(
     domain = results.front();
   }
 
+  bool hasCustomAvailability =
+      ctx.LangOpts.hasFeature(Feature::CustomAvailability);
+  bool hasSwiftRuntimeAvailability =
+      ctx.LangOpts.hasFeature(Feature::SwiftRuntimeAvailability);
+
   if (!domain) {
     auto domainString = identifier.str();
+    bool downgradeErrors =
+        !hasCustomAvailability || declContext->isInSwiftinterface();
     if (auto suggestion = closestCorrectedPlatformString(domainString)) {
       diags
           .diagnose(loc, diag::availability_suggest_platform_name, identifier,
                     *suggestion)
+          .limitBehaviorIf(downgradeErrors, DiagnosticBehavior::Warning)
           .fixItReplace(SourceRange(loc), *suggestion);
     } else {
-      diags.diagnose(loc, diag::availability_unrecognized_platform_name,
-                     identifier);
+      diags
+          .diagnose(loc, diag::availability_unrecognized_platform_name,
+                    identifier)
+          .limitBehaviorIf(downgradeErrors, DiagnosticBehavior::Warning);
     }
     return std::nullopt;
   }
 
-  if (domain->isCustom() &&
-      !ctx.LangOpts.hasFeature(Feature::CustomAvailability) &&
-      !declContext->isInSwiftinterface()) {
-    diags.diagnose(loc, diag::attr_availability_requires_custom_availability,
-                   *domain);
+  // The remaining diagnostics are suppressed in .swiftinterfaces.
+  if (declContext->isInSwiftinterface())
+    return domain;
+
+  // Use of custom domains requires the 'CustomAvailability' feature.
+  if (domain->isCustom() && !hasCustomAvailability) {
+    diags.diagnose(loc, diag::availability_domain_requires_feature, *domain,
+                   "CustomAvailability");
+    return std::nullopt;
+  }
+
+  // Use of the 'Swift' domain requires the 'SwiftRuntimeAvailability' feature.
+  if (!hasSwiftRuntimeAvailability && domain->isSwiftRuntime()) {
+    diags.diagnose(loc, diag::availability_domain_requires_feature, *domain,
+                   "SwiftRuntimeAvailability");
     return std::nullopt;
   }
 
+  if (domain->isSwiftLanguageMode()) {
+    // When the 'SwiftRuntimeAvailability' feature is enabled, the 'swift'
+    // domain spelling is deprecated in favor of 'SwiftLanguageMode'.
+    if (hasSwiftRuntimeAvailability && identifier.str() == "swift") {
+      diags
+          .diagnose(loc, diag::availability_domain_renamed, identifier,
+                    "SwiftLanguageMode")
+          .fixItReplace(SourceRange(loc), "SwiftLanguageMode");
+    }
+
+    // Use of the 'SwiftLanguageMode' domain spelling requires the
+    // 'SwiftRuntimeAvailability' feature.
+    if (!hasSwiftRuntimeAvailability &&
+        identifier.str() == "SwiftLanguageMode") {
+      diags.diagnose(loc, diag::availability_domain_requires_feature, *domain,
+                     "SwiftRuntimeAvailability");
+      return std::nullopt;
+    }
+  }
+
   return domain;
 }
 
diff --git a/lib/AST/AvailabilityQuery.cpp b/lib/AST/AvailabilityQuery.cpp
new file mode 100644
index 0000000000000..16b3b41c2ae88
--- /dev/null
+++ b/lib/AST/AvailabilityQuery.cpp
@@ -0,0 +1,148 @@
+//===--- AvailabilityQuery.cpp - Swift Availability Queries ---------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/AST/AvailabilityQuery.h"
+#include "swift/AST/ASTContext.h"
+#include "swift/AST/Decl.h"
+#include "swift/Basic/Platform.h"
+
+using namespace swift;
+
+static void unpackVersion(const llvm::VersionTuple &version,
+                          llvm::SmallVectorImpl<unsigned> &arguments) {
+  arguments.push_back(version.getMajor());
+  arguments.push_back(version.getMinor().value_or(0));
+  arguments.push_back(version.getSubminor().value_or(0));
+}
+
+static FuncDecl *
+getOSVersionRangeCheck(const llvm::VersionTuple &version,
+                       llvm::SmallVectorImpl<unsigned> &arguments,
+                       ASTContext &ctx, bool forTargetVariant) {
+  unpackVersion(version, arguments);
+  return forTargetVariant ? ctx.getIsVariantOSVersionAtLeastDecl()
+                          : ctx.getIsOSVersionAtLeastDecl();
+}
+
+static FuncDecl *getOSVersionOrVariantVersionRangeCheck(
+    const llvm::VersionTuple &targetVersion,
+    const llvm::VersionTuple &variantVersion,
+    llvm::SmallVectorImpl<unsigned> &arguments, ASTContext &ctx) {
+  unpackVersion(targetVersion, arguments);
+  unpackVersion(variantVersion, arguments);
+  return ctx.getIsOSVersionAtLeastOrVariantVersionAtLeast();
+}
+
+static FuncDecl *
+getZipperedOSVersionRangeCheck(const AvailabilityQuery &query,
+                               llvm::SmallVectorImpl<unsigned> &arguments,
+                               ASTContext &ctx) {
+
+  auto targetVersion = query.getPrimaryArgument();
+  auto variantVersion = query.getVariantArgument();
+  DEBUG_ASSERT(targetVersion || variantVersion);
+
+  // We're building zippered, so we need to pass both macOS and iOS versions to
+  // the runtime version range check. At run time that check will determine what
+  // kind of process this code is loaded into. In a macOS process it will use
+  // the macOS version; in an macCatalyst process it will use the iOS version.
+  llvm::Triple targetTriple = ctx.LangOpts.Target;
+  llvm::Triple variantTriple = *ctx.LangOpts.TargetVariant;
+
+  // From perspective of the driver and most of the frontend, -target and
+  // -target-variant are symmetric. That is, the user can pass either:
+  //    -target x86_64-apple-macosx10.15 \
+  //    -target-variant x86_64-apple-ios13.1-macabi
+  // or:
+  //    -target x86_64-apple-ios13.1-macabi \
+  //    -target-variant x86_64-apple-macosx10.15
+  //
+  // However, the runtime availability-checking entry points need to compare
+  // against an actual running OS version and so can't be symmetric. Here we
+  // standardize on "target" means macOS version and "targetVariant" means iOS
+  // version.
+  if (tripleIsMacCatalystEnvironment(targetTriple)) {
+    DEBUG_ASSERT(variantTriple.isMacOSX());
+    // Normalize so that "variant" always means iOS version.
+    std::swap(targetVersion, variantVersion);
+    std::swap(targetTriple, variantTriple);
+  }
+
+  // The variant-only availability-checking entrypoint is not part of the
+  // Swift 5.0 ABI. It is only available in macOS 10.15 and above.
+  bool isVariantEntrypointAvailable = !targetTriple.isMacOSXVersionLT(10, 15);
+
+  // If there is no check for the target but there is for the variant, then we
+  // only need to emit code for the variant check.
+  if (isVariantEntrypointAvailable && !targetVersion && variantVersion)
+    return getOSVersionRangeCheck(*variantVersion, arguments, ctx,
+                                  /*forVariant=*/true);
+
+  // Similarly, if there is a check for the target but not for the target
+  // variant then we only to emit code for the target check.
+  if (targetVersion && !variantVersion)
+    return getOSVersionRangeCheck(*targetVersion, arguments, ctx,
+                                  /*forTargetVariant=*/false);
+
+  if (!isVariantEntrypointAvailable || (targetVersion && variantVersion)) {
+
+    // If the variant-only entrypoint isn't available (as is the case
+    // pre-macOS 10.15) we need to use the zippered entrypoint (which is part of
+    // the Swift 5.0 ABI) even when the macOS version is '*' (all). In this
+    // case, use the minimum macOS deployment version from the target triple.
+    // This ensures the check always passes on macOS.
+    if (!isVariantEntrypointAvailable && !targetVersion) {
+      DEBUG_ASSERT(targetTriple.isMacOSX());
+
+      llvm::VersionTuple macosVersion;
+      targetTriple.getMacOSXVersion(macosVersion);
+      targetVersion = macosVersion;
+    }
+
+    return getOSVersionOrVariantVersionRangeCheck(
+        *targetVersion, *variantVersion, arguments, ctx);
+  }
+
+  llvm_unreachable("Unhandled zippered configuration");
+}
+
+static FuncDecl *
+getOSAvailabilityDeclAndArguments(const AvailabilityQuery &query,
+                                  llvm::SmallVectorImpl<unsigned> &arguments,
+                                  ASTContext &ctx) {
+  if (ctx.LangOpts.TargetVariant)
+    return getZipperedOSVersionRangeCheck(query, arguments, ctx);
+
+  bool isMacCatalyst = tripleIsMacCatalystEnvironment(ctx.LangOpts.Target);
+  return getOSVersionRangeCheck(query.getPrimaryArgument().value(), arguments,
+                                ctx, isMacCatalyst);
+}
+
+FuncDecl *AvailabilityQuery::getDynamicQueryDeclAndArguments(
+    llvm::SmallVectorImpl<unsigned> &arguments, ASTContext &ctx) const {
+  auto domain = getDomain();
+  switch (domain.getKind()) {
+  case AvailabilityDomain::Kind::Universal:
+  case AvailabilityDomain::Kind::SwiftLanguageMode:
+  case AvailabilityDomain::Kind::SwiftRuntime:
+  case AvailabilityDomain::Kind::PackageDescription:
+  case AvailabilityDomain::Kind::Embedded:
+    return nullptr;
+  case AvailabilityDomain::Kind::Platform:
+    return getOSAvailabilityDeclAndArguments(*this, arguments, ctx);
+  case AvailabilityDomain::Kind::Custom:
+    auto customDomain = domain.getCustomDomain();
+    ASSERT(customDomain);
+
+    return customDomain->getPredicateFunc();
+  }
+}
diff --git a/lib/AST/AvailabilityScope.cpp b/lib/AST/AvailabilityScope.cpp
index e24ba24da5e0f..81558b9ca272a 100644
--- a/lib/AST/AvailabilityScope.cpp
+++ b/lib/AST/AvailabilityScope.cpp
@@ -17,6 +17,7 @@
 #include "swift/AST/AvailabilityScope.h"
 
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/AvailabilityConstraint.h"
 #include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/AvailabilitySpec.h"
 #include "swift/AST/Decl.h"
@@ -356,15 +357,17 @@ SourceRange AvailabilityScope::getAvailabilityConditionVersionSourceRange(
 }
 
 std::optional<const AvailabilityRange>
-AvailabilityScope::getExplicitAvailabilityRange() const {
+AvailabilityScope::getExplicitAvailabilityRange(AvailabilityDomain domain,
+                                                ASTContext &ctx) const {
   switch (getReason()) {
   case Reason::Root:
     return std::nullopt;
 
   case Reason::Decl: {
     auto decl = Node.getAsDecl();
-    if (auto attr = decl->getAvailableAttrForPlatformIntroduction())
-      return attr->getIntroducedRange(decl->getASTContext());
+    if (auto constraint = swift::getAvailabilityConstraintForDeclInDomain(
+            decl, AvailabilityContext::forAlwaysAvailable(ctx), domain))
+      return constraint->getAttr().getIntroducedRange(ctx);
 
     return std::nullopt;
   }
@@ -379,22 +382,12 @@ AvailabilityScope::getExplicitAvailabilityRange() const {
   case Reason::GuardStmtElseBranch:
   case Reason::WhileStmtBody:
     // Availability is inherently explicit for all of these nodes.
-    return getPlatformAvailabilityRange();
+    return getAvailabilityContext().getAvailabilityRange(domain, ctx);
   }
 
   llvm_unreachable("Unhandled Reason in switch.");
 }
 
-static std::string
-stringForAvailability(const AvailabilityRange &availability) {
-  if (availability.isAlwaysAvailable())
-    return "all";
-  if (availability.isKnownUnreachable())
-    return "none";
-
-  return availability.getVersionString();
-}
-
 void AvailabilityScope::print(raw_ostream &OS, SourceManager &SrcMgr,
                               unsigned Indent) const {
   OS.indent(Indent);
@@ -446,9 +439,6 @@ void AvailabilityScope::print(raw_ostream &OS, SourceManager &SrcMgr,
     }
   }
 
-  if (auto explicitAvailability = getExplicitAvailabilityRange())
-    OS << " explicit_version=" << stringForAvailability(*explicitAvailability);
-
   for (AvailabilityScope *Child : Children) {
     OS << '\n';
     Child->print(OS, SrcMgr, Indent + 2);
@@ -519,15 +509,16 @@ static void verificationError(
     ASTContext &ctx, llvm::StringRef msg,
     std::initializer_list<std::pair<const char *, const AvailabilityScope *>>
         labelsAndNodes) {
-  llvm::errs() << msg << "\n";
-  for (auto pair : labelsAndNodes) {
-    auto label = std::get<0>(pair);
-    auto scope = std::get<1>(pair);
-    llvm::errs() << label << ":\n";
-    scope->print(llvm::errs(), ctx.SourceMgr);
-    llvm::errs() << "\n";
-  }
-  abort();
+  ABORT([&](auto &out) {
+    out << msg << "\n";
+    for (auto pair : labelsAndNodes) {
+      auto label = std::get<0>(pair);
+      auto scope = std::get<1>(pair);
+      out << label << ":\n";
+      scope->print(out, ctx.SourceMgr);
+      out << "\n";
+    }
+  });
 }
 
 void AvailabilityScope::verify(const AvailabilityScope *parent,
diff --git a/lib/AST/AvailabilityScopeBuilder.cpp b/lib/AST/AvailabilityScopeBuilder.cpp
index f819837317700..47273ff7ac710 100644
--- a/lib/AST/AvailabilityScopeBuilder.cpp
+++ b/lib/AST/AvailabilityScopeBuilder.cpp
@@ -18,6 +18,7 @@
 
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTWalker.h"
+#include "swift/AST/AvailabilityConstraint.h"
 #include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/AvailabilitySpec.h"
 #include "swift/AST/Decl.h"
@@ -30,20 +31,6 @@
 
 using namespace swift;
 
-/// Returns true if there is any availability attribute on the declaration
-/// that is active.
-// FIXME: [availability] De-duplicate this with TypeCheckAvailability.cpp.
-static bool hasActiveAvailableAttribute(const Decl *decl, ASTContext &ctx) {
-  decl = decl->getAbstractSyntaxDeclForAttributes();
-
-  for (auto attr : decl->getSemanticAvailableAttrs()) {
-    if (attr.isActive(ctx))
-      return true;
-  }
-
-  return false;
-}
-
 static bool computeContainedByDeploymentTarget(AvailabilityScope *scope,
                                                ASTContext &ctx) {
   return scope->getPlatformAvailabilityRange().isContainedIn(
@@ -140,7 +127,7 @@ class AvailabilityScopeBuilder : private ASTWalker {
   }
 
   const char *stackTraceAction() const {
-    return "building availabilty scope for";
+    return "building availability scope for";
   }
 
   friend class swift::ExpandChildAvailabilityScopesRequest;
@@ -397,7 +384,7 @@ class AvailabilityScopeBuilder : private ASTWalker {
       return nullptr;
 
     // Declarations with explicit availability attributes always get a scope.
-    if (hasActiveAvailableAttribute(decl, Context)) {
+    if (decl->hasAnyActiveAvailableAttr()) {
       return AvailabilityScope::createForDecl(
           Context, decl, getCurrentScope(),
           getEffectiveAvailabilityForDeclSignature(decl),
@@ -423,16 +410,20 @@ class AvailabilityScopeBuilder : private ASTWalker {
   getEffectiveAvailabilityForDeclSignature(const Decl *decl) {
     auto effectiveIntroduction = AvailabilityRange::alwaysAvailable();
 
-    // Availability attributes are found abstract syntax decls.
+    // Availability attributes are found on abstract syntax decls.
     decl = decl->getAbstractSyntaxDeclForAttributes();
 
     // As a special case, extension decls are treated as effectively as
     // available as the nominal type they extend, up to the deployment target.
     // This rule is a convenience for library authors who have written
-    // extensions without specifying availabilty on the extension itself.
+    // extensions without specifying platform availability on the extension
+    // itself.
     if (auto *extension = dyn_cast<ExtensionDecl>(decl)) {
       auto extendedType = extension->getExtendedType();
-      if (extendedType && !hasActiveAvailableAttribute(decl, Context)) {
+      if (extendedType && !decl->hasAnyMatchingActiveAvailableAttr(
+                              [](SemanticAvailableAttr attr) -> bool {
+                                return attr.getDomain().isPlatform();
+                              })) {
         effectiveIntroduction.intersectWith(
             swift::AvailabilityInference::inferForType(extendedType));
 
@@ -471,10 +462,17 @@ class AvailabilityScopeBuilder : private ASTWalker {
     // As a convenience, explicitly unavailable decls are constrained to the
     // deployment target. There's not much benefit to checking these decls at a
     // lower availability version floor since they can't be invoked by clients.
-    if (getCurrentScope()->getAvailabilityContext().isUnavailable() ||
-        decl->isUnavailable())
+    auto context = getCurrentScope()->getAvailabilityContext();
+    if (context.isUnavailable())
       return true;
 
+    // Check whether the decl is unavailable relative to the current context.
+    if (auto constraint = getAvailabilityConstraintsForDecl(decl, context)
+                              .getPrimaryConstraint()) {
+      if (constraint->isUnavailable())
+        return true;
+    }
+
     // To remain compatible with a lot of existing SPIs that are declared
     // without availability attributes, constrain them to the deployment target
     // too.
@@ -594,8 +592,7 @@ class AvailabilityScopeBuilder : private ASTWalker {
   }
 
   void buildContextsForBodyOfDecl(Decl *decl) {
-    // Are we already constrained by the deployment target and the declaration
-    // doesn't explicitly allow unsafe constructs in its definition, adding
+    // If we are already constrained by the deployment target then adding
     // new contexts won't change availability.
     if (isCurrentScopeContainedByDeploymentTarget())
       return;
@@ -609,8 +606,10 @@ class AvailabilityScopeBuilder : private ASTWalker {
       // Apply deployment-target availability if appropriate for this body.
       if (!isCurrentScopeContainedByDeploymentTarget() &&
           bodyIsDeploymentTarget(decl)) {
-        availability.constrainWithPlatformRange(
-            AvailabilityRange::forDeploymentTarget(Context), Context);
+        // Also constrain availability with the decl itself to handle the case
+        // where the decl becomes obsolete at the deployment target.
+        availability.constrainWithDeclAndPlatformRange(
+            decl, AvailabilityRange::forDeploymentTarget(Context));
       }
 
       nodesAndScopes.push_back(
@@ -824,6 +823,75 @@ class AvailabilityScopeBuilder : private ASTWalker {
     pushContext(fallthroughScope, parentBrace);
   }
 
+  AvailabilityQuery buildAvailabilityQuery(
+      const SemanticAvailabilitySpec spec,
+      const std::optional<SemanticAvailabilitySpec> &variantSpec) {
+    auto domain = spec.getDomain();
+
+    // Variant availability specfications are only supported for platform
+    // domains when compiling with a -target-variant.
+    if (!Context.LangOpts.TargetVariant)
+      ASSERT(!variantSpec);
+
+    auto runtimeRangeForSpec =
+        [](const std::optional<SemanticAvailabilitySpec> &spec)
+        -> std::optional<AvailabilityRange> {
+      if (!spec || spec->isWildcard() || !spec->getDomain().isVersioned())
+        return std::nullopt;
+
+      return AvailabilityRange(spec->getRuntimeVersion());
+    };
+
+    auto primaryRange = runtimeRangeForSpec(spec);
+    auto variantRange = runtimeRangeForSpec(variantSpec);
+
+    switch (domain.getKind()) {
+    case AvailabilityDomain::Kind::Embedded:
+    case AvailabilityDomain::Kind::SwiftLanguageMode:
+    case AvailabilityDomain::Kind::PackageDescription:
+      // These domains don't support queries.
+      llvm::report_fatal_error("unsupported domain");
+
+    case AvailabilityDomain::Kind::Universal:
+      DEBUG_ASSERT(spec.isWildcard());
+
+      // If all of the specs that matched are '*', then the query trivially
+      // evaluates to "true" at compile time.
+      if (!variantRange)
+        return AvailabilityQuery::constant(domain, true);
+
+      // Otherwise, generate a dynamic query for the variant spec. For example,
+      // when compiling zippered for macOS, this should generate a query that
+      // just checks the iOS version at runtime:
+      //
+      //    if #available(iOS 18, *) { ... }
+      //
+      return AvailabilityQuery::dynamic(variantSpec->getDomain(), primaryRange,
+                                        variantRange);
+
+    case AvailabilityDomain::Kind::SwiftRuntime:
+    case AvailabilityDomain::Kind::Platform:
+      // Platform and Swift runtime checks are always dynamic. The SIL optimizer
+      // is responsible eliminating these checks when it can prove that they can
+      // never fail (due to the deployment target). We can't perform that
+      // analysis here because it may depend on inlining.
+      return AvailabilityQuery::dynamic(domain, primaryRange, variantRange);
+    case AvailabilityDomain::Kind::Custom:
+      auto customDomain = domain.getCustomDomain();
+      ASSERT(customDomain);
+
+      switch (customDomain->getKind()) {
+      case CustomAvailabilityDomain::Kind::Enabled:
+      case CustomAvailabilityDomain::Kind::AlwaysEnabled:
+        return AvailabilityQuery::constant(domain, true);
+      case CustomAvailabilityDomain::Kind::Disabled:
+        return AvailabilityQuery::constant(domain, false);
+      case CustomAvailabilityDomain::Kind::Dynamic:
+        return AvailabilityQuery::dynamic(domain, primaryRange, variantRange);
+      }
+    }
+  }
+
   /// Build the availability scopes for a StmtCondition and return a pair of
   /// optional availability contexts, the first for the true branch and the
   /// second for the false branch. A value of `nullopt` for a given branch
@@ -982,23 +1050,19 @@ class AvailabilityScopeBuilder : private ASTWalker {
         continue;
       }
 
-      auto runtimeQueryRange = runtimeQueryRangeForSpec(*spec);
-      query->setAvailableRange(runtimeQueryRange.getRawVersionRange());
-
       // When compiling zippered for macCatalyst, we need to collect both
       // a macOS version (the target version) and an iOS/macCatalyst version
       // (the target-variant). These versions will both be passed to a runtime
       // entrypoint that will check either the macOS version or the iOS
       // version depending on the kind of process this code is loaded into.
-      if (Context.LangOpts.TargetVariant) {
-        auto variantSpec =
-            bestActiveSpecForQuery(query, /*ForTargetVariant*/ true);
-        if (variantSpec) {
-          auto variantQueryRange = runtimeQueryRangeForSpec(*variantSpec);
-          query->setVariantAvailableRange(
-              variantQueryRange.getRawVersionRange());
-        }
-      }
+      std::optional<SemanticAvailabilitySpec> variantSpec =
+          (Context.LangOpts.TargetVariant)
+              ? bestActiveSpecForQuery(query, /*ForTargetVariant*/ true)
+              : std::nullopt;
+
+      query->setAvailabilityQuery(
+          buildAvailabilityQuery(*spec, variantSpec)
+              .asUnavailable(query->isUnavailability()));
 
       // Wildcards are expected to be "useless". There may be other specs in
       // this query that are useful when compiling for other platforms.
@@ -1021,9 +1085,9 @@ class AvailabilityScopeBuilder : private ASTWalker {
         // current scope is completely contained in the range for the spec, then
         // a version query can never be false, so the spec is useless.
         // If so, report this.
-        // FIXME: [availability] Diagnose non-platform queries as useless too.
-        auto explicitRange = currentScope->getExplicitAvailabilityRange();
-        if (domain.isPlatform() && explicitRange && trueRange &&
+        auto explicitRange =
+            currentScope->getExplicitAvailabilityRange(domain, Context);
+        if (explicitRange && trueRange &&
             explicitRange->isContainedIn(*trueRange)) {
           // Platform unavailability queries never refine availability so don't
           // diangose them.
@@ -1032,17 +1096,9 @@ class AvailabilityScopeBuilder : private ASTWalker {
 
           DiagnosticEngine &diags = Context.Diags;
           if (currentScope->getReason() != AvailabilityScope::Reason::Root) {
-            PlatformKind bestPlatform = targetPlatform(Context.LangOpts);
-
-            // If possible, try to report the diagnostic in terms for the
-            // platform the user uttered in the '#available()'. For a platform
-            // that inherits availability from another platform it may be
-            // different from the platform specified in the target triple.
-            if (domain.getPlatformKind() != PlatformKind::none)
-              bestPlatform = domain.getPlatformKind();
             diags.diagnose(query->getLoc(),
                            diag::availability_query_useless_enclosing_scope,
-                           platformString(bestPlatform));
+                           domain.getNameForAttributePrinting());
             diags.diagnose(
                 currentScope->getIntroductionLoc(),
                 diag::availability_query_useless_enclosing_scope_here);
@@ -1164,24 +1220,6 @@ class AvailabilityScopeBuilder : private ASTWalker {
     }
   }
 
-  /// Return the availability context for the given spec.
-  AvailabilityRange runtimeQueryRangeForSpec(SemanticAvailabilitySpec spec) {
-    if (spec.isWildcard())
-      return AvailabilityRange::alwaysAvailable();
-
-    auto domain = spec.getDomain();
-    if (domain.isVersioned())
-      return AvailabilityRange(spec.getRuntimeVersion());
-
-    // If it's not a versioned domain, we must be querying whether a domain is
-    // present or absent.
-    if (domain.isCustom() && domain.getCustomDomain()->getKind() ==
-                                 CustomAvailabilityDomain::Kind::Disabled)
-      return AvailabilityRange::neverAvailable();
-
-    return AvailabilityRange::alwaysAvailable();
-  }
-
   /// For the given spec, returns a pair of availability ranges. The first range
   /// is for the if/then flow and the second is for the if/else flow.
   std::pair<std::optional<AvailabilityRange>, std::optional<AvailabilityRange>>
diff --git a/lib/AST/Bridging/ASTContextBridging.cpp b/lib/AST/Bridging/ASTContextBridging.cpp
index 616497016015d..18eaf236ebc81 100644
--- a/lib/AST/Bridging/ASTContextBridging.cpp
+++ b/lib/AST/Bridging/ASTContextBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -13,7 +13,9 @@
 #include "swift/AST/ASTBridging.h"
 
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/ASTContextGlobalCache.h"
 #include "swift/AST/AvailabilitySpec.h"
+#include "swift/Bridging/BasicSwift.h"
 
 using namespace swift;
 
@@ -21,132 +23,36 @@ using namespace swift;
 // MARK: ASTContext
 //===----------------------------------------------------------------------===//
 
-BridgedIdentifier BridgedASTContext_getIdentifier(BridgedASTContext cContext,
-                                                  BridgedStringRef cStr) {
+Identifier BridgedASTContext_getIdentifier(BridgedASTContext cContext,
+                                           BridgedStringRef cStr) {
   return cContext.unbridged().getIdentifier(cStr.unbridged());
 }
 
-BridgedIdentifier
-BridgedASTContext_getDollarIdentifier(BridgedASTContext cContext, size_t idx) {
-  return cContext.unbridged().getDollarIdentifier(idx);
-}
-
-bool BridgedASTContext_langOptsHasFeature(BridgedASTContext cContext,
-                                          BridgedFeature feature) {
-  return cContext.unbridged().LangOpts.hasFeature((Feature)feature);
-}
-
-unsigned BridgedASTContext_majorLanguageVersion(BridgedASTContext cContext) {
-  return cContext.unbridged().LangOpts.EffectiveLanguageVersion[0];
-}
-
-bool BridgedASTContext_langOptsCustomConditionSet(BridgedASTContext cContext,
-                                                  BridgedStringRef cName) {
-  ASTContext &ctx = cContext.unbridged();
-  auto name = cName.unbridged();
-  if (name.starts_with("$") && ctx.LangOpts.hasFeature(name.drop_front()))
-    return true;
-
-  return ctx.LangOpts.isCustomConditionalCompilationFlagSet(name);
-}
-
-bool BridgedASTContext_langOptsHasFeatureNamed(BridgedASTContext cContext,
-                                               BridgedStringRef cName) {
-  return cContext.unbridged().LangOpts.hasFeature(cName.unbridged());
-}
-
-bool BridgedASTContext_langOptsHasAttributeNamed(BridgedASTContext cContext,
-                                                 BridgedStringRef cName) {
-  return hasAttribute(cContext.unbridged().LangOpts, cName.unbridged());
-}
-
-bool BridgedASTContext_langOptsIsActiveTargetOS(BridgedASTContext cContext,
-                                                BridgedStringRef cName) {
-  return cContext.unbridged().LangOpts.checkPlatformCondition(
-      PlatformConditionKind::OS, cName.unbridged());
-}
-
-bool BridgedASTContext_langOptsIsActiveTargetArchitecture(
-    BridgedASTContext cContext, BridgedStringRef cName) {
-  return cContext.unbridged().LangOpts.checkPlatformCondition(
-      PlatformConditionKind::Arch, cName.unbridged());
-}
-
-bool BridgedASTContext_langOptsIsActiveTargetEnvironment(
-    BridgedASTContext cContext, BridgedStringRef cName) {
-  return cContext.unbridged().LangOpts.checkPlatformCondition(
-      PlatformConditionKind::TargetEnvironment, cName.unbridged());
-}
-
-bool BridgedASTContext_langOptsIsActiveTargetRuntime(BridgedASTContext cContext,
-                                                     BridgedStringRef cName) {
-  return cContext.unbridged().LangOpts.checkPlatformCondition(
-      PlatformConditionKind::Runtime, cName.unbridged());
-}
-
-bool BridgedASTContext_langOptsIsActiveTargetPtrAuth(BridgedASTContext cContext,
-                                                     BridgedStringRef cName) {
-  return cContext.unbridged().LangOpts.checkPlatformCondition(
-      PlatformConditionKind::PtrAuth, cName.unbridged());
-}
-
-unsigned
-BridgedASTContext_langOptsTargetPointerBitWidth(BridgedASTContext cContext) {
-  return cContext.unbridged().LangOpts.Target.isArch64Bit()   ? 64
-         : cContext.unbridged().LangOpts.Target.isArch32Bit() ? 32
-         : cContext.unbridged().LangOpts.Target.isArch16Bit() ? 16
-                                                              : 0;
-}
-
-bool BridgedASTContext_langOptsAttachCommentsToDecls(
-    BridgedASTContext cContext) {
-  return cContext.unbridged().LangOpts.AttachCommentsToDecls;
-}
-
-BridgedEndianness
-BridgedASTContext_langOptsTargetEndianness(BridgedASTContext cContext) {
-  return cContext.unbridged().LangOpts.Target.isLittleEndian() ? EndianLittle
-                                                               : EndianBig;
+Identifier BridgedASTContext__getIdentifier(BridgedASTContext cContext,
+                                            BridgedStringRef cStr) {
+  return cContext.unbridged().getIdentifier(cStr.unbridged());
 }
 
-/// Convert an array of numbers into a form we can use in Swift.
-namespace {
-template <typename Arr>
-SwiftInt convertArray(const Arr &array, SwiftInt **cElements) {
-  SwiftInt numElements = array.size();
-  *cElements = (SwiftInt *)malloc(sizeof(SwiftInt) * numElements);
-  for (SwiftInt i = 0; i != numElements; ++i)
-    (*cElements)[i] = array[i];
-  return numElements;
+Identifier BridgedASTContext_getDollarIdentifier(BridgedASTContext cContext,
+                                                 size_t idx) {
+  return cContext.unbridged().getDollarIdentifier(idx);
 }
-} // namespace
 
-void deallocateIntBuffer(SwiftInt *_Nullable cComponents) { free(cComponents); }
-
-SwiftInt
-BridgedASTContext_langOptsGetLanguageVersion(BridgedASTContext cContext,
-                                             SwiftInt **cComponents) {
-  auto theVersion = cContext.unbridged().LangOpts.EffectiveLanguageVersion;
-  return convertArray(theVersion, cComponents);
+BridgedLangOptions BridgedASTContext_langOpts(BridgedASTContext cContext) {
+  return cContext.unbridged().LangOpts;
 }
 
-SWIFT_NAME("BridgedASTContext.langOptsGetCompilerVersion(self:_:)")
-SwiftInt
-BridgedASTContext_langOptsGetCompilerVersion(BridgedASTContext cContext,
-                                             SwiftInt **cComponents) {
-  auto theVersion = version::Version::getCurrentLanguageVersion();
-  return convertArray(theVersion, cComponents);
+unsigned BridgedASTContext::getMajorLanguageVersion() const {
+  return unbridged().LangOpts.EffectiveLanguageVersion[0];
 }
 
-SwiftInt BridgedASTContext_langOptsGetTargetAtomicBitWidths(
-    BridgedASTContext cContext, SwiftInt *_Nullable *_Nonnull cElements) {
-  return convertArray(cContext.unbridged().LangOpts.getAtomicBitWidthValues(),
-                      cElements);
+BridgedDiagnosticEngine BridgedASTContext::getDiags() const {
+  return &unbridged().Diags;
 }
 
 bool BridgedASTContext_canImport(BridgedASTContext cContext,
                                  BridgedStringRef importPath,
-                                 BridgedSourceLoc canImportLoc,
+                                 SourceLoc canImportLoc,
                                  BridgedCanImportVersion versionKind,
                                  const SwiftInt *_Nullable versionComponents,
                                  SwiftInt numVersionComponents) {
@@ -173,13 +79,26 @@ bool BridgedASTContext_canImport(BridgedASTContext cContext,
 
   ImportPath::Module::Builder builder(cContext.unbridged(),
                                       importPath.unbridged(), /*separator=*/'.',
-                                      canImportLoc.unbridged());
+                                      canImportLoc);
   return cContext.unbridged().canImportModule(
-      builder.get(), canImportLoc.unbridged(), version,
+      builder.get(), canImportLoc, version,
       versionKind == CanImportUnderlyingVersion);
 }
 
-BridgedAvailabilityMacroMap
-BridgedASTContext_getAvailabilityMacroMap(BridgedASTContext cContext) {
-  return &cContext.unbridged().getAvailabilityMacroMap();
+BridgedAvailabilityMacroMap BridgedASTContext::getAvailabilityMacroMap() const {
+  return &unbridged().getAvailabilityMacroMap();
+}
+
+void *BridgedASTContext_staticBuildConfiguration(BridgedASTContext cContext) {
+  ASTContext &ctx = cContext.unbridged();
+  void *staticBuildConfiguration = ctx.getGlobalCache().StaticBuildConfiguration;
+  if (!staticBuildConfiguration) {
+    staticBuildConfiguration =
+        swift_Basic_createStaticBuildConfiguration(ctx.LangOpts);
+    ctx.addCleanup([staticBuildConfiguration] {
+      swift_Basic_freeStaticBuildConfiguration(staticBuildConfiguration);
+    });
+  }
+
+  return staticBuildConfiguration;
 }
diff --git a/lib/AST/Bridging/AvailabilityBridging.cpp b/lib/AST/Bridging/AvailabilityBridging.cpp
index fce3167dc803d..9cd9762cd0f90 100644
--- a/lib/AST/Bridging/AvailabilityBridging.cpp
+++ b/lib/AST/Bridging/AvailabilityBridging.cpp
@@ -12,7 +12,7 @@
 
 #include "swift/AST/ASTBridging.h"
 #include "swift/AST/AvailabilitySpec.h"
-#include "swift/AST/PlatformKind.h"
+#include "swift/AST/PlatformKindUtils.h"
 
 using namespace swift;
 
@@ -43,36 +43,16 @@ BridgedAvailabilityMacroMap_getSpecs(BridgedAvailabilityMacroMap map,
 // MARK: PlatformKind
 //===----------------------------------------------------------------------===//
 
-BridgedPlatformKind BridgedPlatformKind_fromString(BridgedStringRef cStr) {
+BridgedOptionalPlatformKind PlatformKind_fromString(BridgedStringRef cStr) {
   auto optKind = platformFromString(cStr.unbridged());
-  if (!optKind)
-    return BridgedPlatformKind_None;
-
-  switch (*optKind) {
-  case PlatformKind::none:
-    return BridgedPlatformKind_None;
-#define AVAILABILITY_PLATFORM(X, PrettyName)                                   \
-  case PlatformKind::X:                                                        \
-    return BridgedPlatformKind_##X;
-#include "swift/AST/PlatformKinds.def"
+  if (!optKind) {
+    return BridgedOptionalPlatformKind();
   }
+  return *optKind;
 }
 
-BridgedPlatformKind
-BridgedPlatformKind_fromIdentifier(BridgedIdentifier cIdent) {
-  return BridgedPlatformKind_fromString(cIdent.unbridged().str());
-}
-
-PlatformKind unbridge(BridgedPlatformKind platform) {
-  switch (platform) {
-  case BridgedPlatformKind_None:
-    return PlatformKind::none;
-#define AVAILABILITY_PLATFORM(X, PrettyName)                                   \
-  case BridgedPlatformKind_##X:                                                \
-    return PlatformKind::X;
-#include "swift/AST/PlatformKinds.def"
-  }
-  llvm_unreachable("unhandled enum value");
+BridgedOptionalPlatformKind PlatformKind_fromIdentifier(Identifier ident) {
+  return PlatformKind_fromString(ident.str());
 }
 
 //===----------------------------------------------------------------------===//
@@ -81,17 +61,15 @@ PlatformKind unbridge(BridgedPlatformKind platform) {
 
 BridgedAvailabilitySpec
 BridgedAvailabilitySpec_createWildcard(BridgedASTContext cContext,
-                                       BridgedSourceLoc cLoc) {
-  return AvailabilitySpec::createWildcard(cContext.unbridged(),
-                                          cLoc.unbridged());
+                                       SourceLoc loc) {
+  return AvailabilitySpec::createWildcard(cContext.unbridged(), loc);
 }
 
 BridgedAvailabilitySpec BridgedAvailabilitySpec_createForDomainIdentifier(
-    BridgedASTContext cContext, BridgedIdentifier cName, BridgedSourceLoc cLoc,
-    BridgedVersionTuple cVersion, BridgedSourceRange cVersionRange) {
+    BridgedASTContext cContext, Identifier name, SourceLoc loc,
+    BridgedVersionTuple cVersion, SourceRange versionRange) {
   return AvailabilitySpec::createForDomainIdentifier(
-      cContext.unbridged(), cName.unbridged(), cLoc.unbridged(),
-      cVersion.unbridged(), cVersionRange.unbridged());
+      cContext.unbridged(), name, loc, cVersion.unbridged(), versionRange);
 }
 
 BridgedAvailabilitySpec
@@ -101,8 +79,8 @@ BridgedAvailabilitySpec_clone(BridgedAvailabilitySpec spec,
 }
 
 void BridgedAvailabilitySpec_setMacroLoc(BridgedAvailabilitySpec spec,
-                                         BridgedSourceLoc cLoc) {
-  spec.unbridged()->setMacroLoc(cLoc.unbridged());
+                                         SourceLoc loc) {
+  spec.unbridged()->setMacroLoc(loc);
 }
 
 BridgedAvailabilityDomainOrIdentifier
@@ -110,7 +88,7 @@ BridgedAvailabilitySpec_getDomainOrIdentifier(BridgedAvailabilitySpec spec) {
   return spec.unbridged()->getDomainOrIdentifier();
 }
 
-BridgedSourceRange
+SourceRange
 BridgedAvailabilitySpec_getSourceRange(BridgedAvailabilitySpec spec) {
   return spec.unbridged()->getSourceRange();
 }
@@ -124,7 +102,7 @@ BridgedAvailabilitySpec_getRawVersion(BridgedAvailabilitySpec spec) {
   return spec.unbridged()->getRawVersion();
 }
 
-BridgedSourceRange
+SourceRange
 BridgedAvailabilitySpec_getVersionRange(BridgedAvailabilitySpec spec) {
   return spec.unbridged()->getVersionSrcRange();
 }
diff --git a/lib/AST/Bridging/DeclAttributeBridging.cpp b/lib/AST/Bridging/DeclAttributeBridging.cpp
index 774879aad0bda..0803748c5d9e2 100644
--- a/lib/AST/Bridging/DeclAttributeBridging.cpp
+++ b/lib/AST/Bridging/DeclAttributeBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -44,13 +44,11 @@ DifferentiabilityKind unbridged(BridgedDifferentiabilityKind cKind) {
 ParsedAutoDiffParameter BridgedParsedAutoDiffParameter::unbridged() const {
   switch (kind) {
   case Kind::Named:
-    return ParsedAutoDiffParameter::getNamedParameter(loc.unbridged(),
-                                                      value.name.unbridged());
+    return ParsedAutoDiffParameter::getNamedParameter(loc, value.name);
   case Kind::Ordered:
-    return ParsedAutoDiffParameter::getOrderedParameter(loc.unbridged(),
-                                                        value.index);
+    return ParsedAutoDiffParameter::getOrderedParameter(loc, value.index);
   case Kind::Self:
-    return ParsedAutoDiffParameter::getSelfParameter(loc.unbridged());
+    return ParsedAutoDiffParameter::getSelfParameter(loc);
   }
   llvm_unreachable("unhandled enum value");
 }
@@ -68,51 +66,29 @@ ParsedAutoDiffParameter BridgedParsedAutoDiffParameter::unbridged() const {
   }
 #include "swift/AST/DeclAttr.def"
 
-BridgedDeclAttrKind BridgedDeclAttrKind_fromString(BridgedStringRef cStr) {
+BridgedOptionalDeclAttrKind
+BridgedOptionalDeclAttrKind_fromString(BridgedStringRef cStr) {
   auto optKind = DeclAttribute::getAttrKindFromString(cStr.unbridged());
-  if (!optKind)
-    return BridgedDeclAttrKindNone;
-  switch (*optKind) {
-#define DECL_ATTR(_, CLASS, ...)                                               \
-  case DeclAttrKind::CLASS:                                                    \
-    return BridgedDeclAttrKind##CLASS;
-#include "swift/AST/DeclAttr.def"
-  }
-}
-
-std::optional<DeclAttrKind> unbridged(BridgedDeclAttrKind kind) {
-  switch (kind) {
-#define DECL_ATTR(_, CLASS, ...)                                               \
-  case BridgedDeclAttrKind##CLASS:                                             \
-    return DeclAttrKind::CLASS;
-#include "swift/AST/DeclAttr.def"
-  case BridgedDeclAttrKindNone:
-    return std::nullopt;
+  if (!optKind) {
+    return BridgedOptionalDeclAttrKind();
   }
-  llvm_unreachable("unhandled enum value");
+  return *optKind;
 }
 
-BridgedDeclAttribute BridgedDeclAttribute_createSimple(
-    BridgedASTContext cContext, BridgedDeclAttrKind cKind,
-    BridgedSourceLoc cAtLoc, BridgedSourceLoc cAttrLoc) {
-  auto optKind = unbridged(cKind);
-  assert(optKind && "creating attribute of invalid kind?");
-  return DeclAttribute::createSimple(cContext.unbridged(), *optKind,
-                                     cAtLoc.unbridged(), cAttrLoc.unbridged());
+BridgedDeclAttribute
+BridgedDeclAttribute_createSimple(BridgedASTContext cContext,
+                                  swift::DeclAttrKind kind, SourceLoc atLoc,
+                                  SourceLoc attrLoc) {
+  return DeclAttribute::createSimple(cContext.unbridged(), kind, atLoc,
+                                     attrLoc);
 }
 
-bool BridgedDeclAttribute_shouldBeRejectedByParser(BridgedDeclAttrKind cKind) {
-  auto optKind = unbridged(cKind);
-  if (!optKind)
-    return false;
-  return DeclAttribute::shouldBeRejectedByParser(*optKind);
+bool BridgedDeclAttribute_shouldBeRejectedByParser(swift::DeclAttrKind kind) {
+  return DeclAttribute::shouldBeRejectedByParser(kind);
 }
 
-bool BridgedDeclAttribute_isDeclModifier(BridgedDeclAttrKind cKind) {
-  auto optKind = unbridged(cKind);
-  if (!optKind)
-    return false;
-  return DeclAttribute::isDeclModifier(*optKind);
+bool BridgedDeclAttribute_isDeclModifier(swift::DeclAttrKind kind) {
+  return DeclAttribute::isDeclModifier(kind);
 }
 
 void BridgedDeclAttributes_add(BridgedDeclAttributes *cAttrs,
@@ -137,32 +113,26 @@ static AvailableAttr::Kind unbridge(BridgedAvailableAttrKind value) {
 }
 
 BridgedAvailableAttr BridgedAvailableAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedIdentifier cDomainIdentifier,
-    BridgedSourceLoc cDomainLoc, BridgedAvailableAttrKind cKind,
-    BridgedStringRef cMessage, BridgedStringRef cRenamed,
-    BridgedVersionTuple cIntroduced, BridgedSourceRange cIntroducedRange,
-    BridgedVersionTuple cDeprecated, BridgedSourceRange cDeprecatedRange,
-    BridgedVersionTuple cObsoleted, BridgedSourceRange cObsoletedRange,
-    bool isSPI) {
-
-  return new (cContext.unbridged())
-      AvailableAttr(cAtLoc.unbridged(), cRange.unbridged(),
-                    cDomainIdentifier.unbridged(), cDomainLoc.unbridged(),
-                    unbridge(cKind), cMessage.unbridged(), cRenamed.unbridged(),
-                    cIntroduced.unbridged(), cIntroducedRange.unbridged(),
-                    cDeprecated.unbridged(), cDeprecatedRange.unbridged(),
-                    cObsoleted.unbridged(), cObsoletedRange.unbridged(),
-                    /*Implicit=*/false,
-                    /*IsSPI=*/isSPI);
-}
-
-BridgedAvailableAttr
-BridgedAvailableAttr_createUnavailableInEmbedded(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cAtLoc,
-                                                 BridgedSourceRange cRange) {
-  return AvailableAttr::createUnavailableInEmbedded(
-      cContext.unbridged(), cAtLoc.unbridged(), cRange.unbridged());
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    Identifier domainIdentifier, SourceLoc domainLoc,
+    BridgedAvailableAttrKind cKind, BridgedStringRef cMessage,
+    BridgedStringRef cRenamed, BridgedVersionTuple cIntroduced,
+    SourceRange introducedRange, BridgedVersionTuple cDeprecated,
+    SourceRange deprecatedRange, BridgedVersionTuple cObsoleted,
+    SourceRange obsoletedRange, bool isSPI) {
+  return new (cContext.unbridged()) AvailableAttr(
+      atLoc, range, domainIdentifier, domainLoc, unbridge(cKind),
+      cMessage.unbridged(), cRenamed.unbridged(), cIntroduced.unbridged(),
+      introducedRange, cDeprecated.unbridged(), deprecatedRange,
+      cObsoleted.unbridged(), obsoletedRange,
+      /*Implicit=*/false,
+      /*IsSPI=*/isSPI);
+}
+
+BridgedAvailableAttr BridgedAvailableAttr_createUnavailableInEmbedded(
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range) {
+  return AvailableAttr::createUnavailableInEmbedded(cContext.unbridged(), atLoc,
+                                                    range);
 }
 
 void BridgedAvailableAttr_setIsGroupMember(BridgedAvailableAttr cAttr) {
@@ -175,201 +145,148 @@ void BridgedAvailableAttr_setIsGroupTerminator(BridgedAvailableAttr cAttr) {
   cAttr.unbridged()->setIsGroupTerminator();
 }
 
-static std::optional<AccessLevel> unbridge(BridgedAccessLevel level) {
-  switch (level) {
-  case BridgedAccessLevelPrivate:
-    return AccessLevel::Private;
-  case BridgedAccessLevelFilePrivate:
-    return AccessLevel::FilePrivate;
-  case BridgedAccessLevelInternal:
-    return AccessLevel::Internal;
-  case BridgedAccessLevelPackage:
-    return AccessLevel::Package;
-  case BridgedAccessLevelPublic:
-    return AccessLevel::Public;
-  case BridgedAccessLevelOpen:
-    return AccessLevel::Open;
-  case BridgedAccessLevelNone:
-    return std::nullopt;
-  }
-  llvm_unreachable("unhandled BridgedAccessLevel");
-}
-
 BridgedABIAttr BridgedABIAttr_createParsed(BridgedASTContext cContext,
-                                           BridgedSourceLoc atLoc,
-                                           BridgedSourceRange range,
+                                           SourceLoc atLoc, SourceRange range,
                                            BridgedNullableDecl abiDecl) {
-  return new (cContext.unbridged()) ABIAttr(abiDecl.unbridged(),
-                                            atLoc.unbridged(),
-                                            range.unbridged(),
+  return new (cContext.unbridged()) ABIAttr(abiDecl.unbridged(), atLoc, range,
                                             /*isImplicit=*/false);
 }
 
 BridgedAccessControlAttr
 BridgedAccessControlAttr_createParsed(BridgedASTContext cContext,
-                                      BridgedSourceRange cRange,
-                                      BridgedAccessLevel cAccessLevel) {
+                                      SourceRange range,
+                                      swift::AccessLevel accessLevel) {
   return new (cContext.unbridged()) AccessControlAttr(
-      /*atLoc=*/{}, cRange.unbridged(), unbridge(cAccessLevel).value());
+      /*atLoc=*/{}, range, accessLevel);
 }
 
 BridgedAlignmentAttr
-BridgedAlignmentAttr_createParsed(BridgedASTContext cContext,
-                                  BridgedSourceLoc cAtLoc,
-                                  BridgedSourceRange cRange, size_t cValue) {
-  return new (cContext.unbridged()) AlignmentAttr(
-      cValue, cAtLoc.unbridged(), cRange.unbridged(), /*Implicit=*/false);
+BridgedAlignmentAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                  SourceRange range, size_t cValue) {
+  return new (cContext.unbridged())
+      AlignmentAttr(cValue, atLoc, range, /*Implicit=*/false);
 }
 
 BridgedAllowFeatureSuppressionAttr
 BridgedAllowFeatureSuppressionAttr_createParsed(BridgedASTContext cContext,
-                                                BridgedSourceLoc cAtLoc,
-                                                BridgedSourceRange cRange,
+                                                SourceLoc atLoc,
+                                                SourceRange range,
                                                 bool inverted,
                                                 BridgedArrayRef cFeatures) {
-  SmallVector<Identifier> features;
-  for (auto elem : cFeatures.unbridged<BridgedIdentifier>())
-    features.push_back(elem.unbridged());
-  return AllowFeatureSuppressionAttr::create(
-      cContext.unbridged(), cAtLoc.unbridged(), cRange.unbridged(),
-      /*implicit*/ false, inverted, features);
+  auto features = cFeatures.unbridged<Identifier>();
+  return AllowFeatureSuppressionAttr::create(cContext.unbridged(), atLoc, range,
+                                             /*implicit*/ false, inverted,
+                                             features);
 }
 
 BridgedBackDeployedAttr BridgedBackDeployedAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedPlatformKind cPlatform,
-    BridgedVersionTuple cVersion) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    swift::PlatformKind platform, BridgedVersionTuple cVersion) {
   return new (cContext.unbridged()) BackDeployedAttr(
-      cAtLoc.unbridged(), cRange.unbridged(), unbridge(cPlatform),
-      cVersion.unbridged(), /*Implicit=*/false);
+      atLoc, range, platform, cVersion.unbridged(), /*Implicit=*/false);
 }
 
 BridgedCDeclAttr BridgedCDeclAttr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAtLoc,
-                                               BridgedSourceRange cRange,
-                                               BridgedStringRef cName) {
+                                               SourceLoc atLoc,
+                                               SourceRange range,
+                                               BridgedStringRef cName,
+                                               bool underscored) {
   return new (cContext.unbridged())
-      CDeclAttr(cName.unbridged(), cAtLoc.unbridged(), cRange.unbridged(),
-                /*Implicit=*/false);
+      CDeclAttr(cName.unbridged(), atLoc, range,
+                /*Implicit=*/false, /*Underscored*/ underscored);
 }
 
 BridgedCustomAttr BridgedCustomAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc, BridgedTypeRepr cType,
+    BridgedASTContext cContext, SourceLoc atLoc, BridgedTypeRepr cType,
     BridgedNullableCustomAttributeInitializer cInitContext,
     BridgedNullableArgumentList cArgumentList) {
   ASTContext &context = cContext.unbridged();
   return CustomAttr::create(
-      context, cAtLoc.unbridged(), new (context) TypeExpr(cType.unbridged()),
+      context, atLoc, new (context) TypeExpr(cType.unbridged()),
       cInitContext.unbridged(), cArgumentList.unbridged());
 }
 
 BridgedDerivativeAttr BridgedDerivativeAttr_createParsedImpl(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNullableTypeRepr cBaseType,
-    BridgedDeclNameRef cOriginalName, BridgedDeclNameLoc cOriginalNameLoc,
-    std::optional<BridgedAccessorKind> cAccessorKind, BridgedArrayRef cParams) {
-  std::optional<AccessorKind> accessorKind;
-  if (cAccessorKind)
-    accessorKind = unbridged(*cAccessorKind);
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedNullableTypeRepr cBaseType, BridgedDeclNameRef cOriginalName,
+    BridgedDeclNameLoc cOriginalNameLoc,
+    std::optional<swift::AccessorKind> AccessorKind, BridgedArrayRef cParams) {
   SmallVector<ParsedAutoDiffParameter, 2> params;
   for (auto &elem : cParams.unbridged<BridgedParsedAutoDiffParameter>())
     params.push_back(elem.unbridged());
 
-  return DerivativeAttr::create(cContext.unbridged(),
-                                /*implicit=*/false, cAtLoc.unbridged(),
-                                cRange.unbridged(), cBaseType.unbridged(),
-                                DeclNameRefWithLoc{cOriginalName.unbridged(),
-                                                   cOriginalNameLoc.unbridged(),
-                                                   accessorKind},
-                                params);
+  return DerivativeAttr::create(
+      cContext.unbridged(),
+      /*implicit=*/false, atLoc, range, cBaseType.unbridged(),
+      DeclNameRefWithLoc{cOriginalName.unbridged(),
+                         cOriginalNameLoc.unbridged(), AccessorKind},
+      params);
 }
 
 BridgedDerivativeAttr BridgedDerivativeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNullableTypeRepr cBaseType,
-    BridgedDeclNameRef cOriginalName, BridgedDeclNameLoc cOriginalNameLoc,
-    BridgedAccessorKind cAccessorKind, BridgedArrayRef cParams) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedNullableTypeRepr cBaseType, BridgedDeclNameRef cOriginalName,
+    BridgedDeclNameLoc cOriginalNameLoc, swift::AccessorKind AccessorKind,
+    BridgedArrayRef cParams) {
   return BridgedDerivativeAttr_createParsedImpl(
-      cContext, cAtLoc, cRange, cBaseType, cOriginalName, cOriginalNameLoc,
-      cAccessorKind, cParams);
+      cContext, atLoc, range, cBaseType, cOriginalName, cOriginalNameLoc,
+      AccessorKind, cParams);
 }
 
 BridgedDerivativeAttr BridgedDerivativeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNullableTypeRepr cBaseType,
-    BridgedDeclNameRef cOriginalName, BridgedDeclNameLoc cOriginalNameLoc,
-    BridgedArrayRef cParams) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedNullableTypeRepr cBaseType, BridgedDeclNameRef cOriginalName,
+    BridgedDeclNameLoc cOriginalNameLoc, BridgedArrayRef cParams) {
   return BridgedDerivativeAttr_createParsedImpl(
-      cContext, cAtLoc, cRange, cBaseType, cOriginalName, cOriginalNameLoc,
+      cContext, atLoc, range, cBaseType, cOriginalName, cOriginalNameLoc,
       /*cAccessorKind=*/std::nullopt, cParams);
 }
 
 BridgedDifferentiableAttr BridgedDifferentiableAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedDifferentiabilityKind cKind,
-    BridgedArrayRef cParams,
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedDifferentiabilityKind cKind, BridgedArrayRef cParams,
     BridgedNullableTrailingWhereClause cGenericWhereClause) {
   SmallVector<ParsedAutoDiffParameter, 2> params;
   for (auto &elem : cParams.unbridged<BridgedParsedAutoDiffParameter>())
     params.push_back(elem.unbridged());
 
   return DifferentiableAttr::create(cContext.unbridged(), /*implicit=*/false,
-                                    cAtLoc.unbridged(), cRange.unbridged(),
-                                    unbridged(cKind), params,
+                                    atLoc, range, unbridged(cKind), params,
                                     cGenericWhereClause.unbridged());
 }
 
 BridgedDynamicReplacementAttr BridgedDynamicReplacementAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cAttrNameLoc, BridgedSourceLoc cLParenLoc,
-    BridgedDeclNameRef cReplacedFunction, BridgedSourceLoc cRParenLoc) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceLoc attrNameLoc,
+    SourceLoc lParenLoc, BridgedDeclNameRef cReplacedFunction,
+    SourceLoc rParenLoc) {
   return DynamicReplacementAttr::create(
-      cContext.unbridged(), cAtLoc.unbridged(), cAttrNameLoc.unbridged(),
-      cLParenLoc.unbridged(), cReplacedFunction.unbridged(),
-      cRParenLoc.unbridged());
+      cContext.unbridged(), atLoc, attrNameLoc, lParenLoc,
+      cReplacedFunction.unbridged(), rParenLoc);
 }
 
 BridgedDocumentationAttr BridgedDocumentationAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cMetadata,
-    BridgedAccessLevel cAccessLevel) {
-  return new (cContext.unbridged()) DocumentationAttr(
-      cAtLoc.unbridged(), cRange.unbridged(), cMetadata.unbridged(),
-      unbridge(cAccessLevel), /*implicit=*/false);
-}
-
-static EffectsKind unbridged(BridgedEffectsKind kind) {
-  switch (kind) {
-  case BridgedEffectsKindReadNone:
-    return EffectsKind::ReadNone;
-  case BridgedEffectsKindReadOnly:
-    return EffectsKind::ReadOnly;
-  case BridgedEffectsKindReleaseNone:
-    return EffectsKind::ReleaseNone;
-  case BridgedEffectsKindReadWrite:
-    return EffectsKind::ReadWrite;
-  case BridgedEffectsKindUnspecified:
-    return EffectsKind::Unspecified;
-  case BridgedEffectsKindCustom:
-    return EffectsKind::Custom;
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedStringRef cMetadata, BridgedOptionalAccessLevel accessLevel) {
+  std::optional<swift::AccessLevel> optAccessLevel;
+  if (accessLevel.getHasValue()) {
+    optAccessLevel.emplace(accessLevel.getValue());
   }
-  llvm_unreachable("unhandled kind");
+  return new (cContext.unbridged()) DocumentationAttr(
+      atLoc, range, cMetadata.unbridged(), optAccessLevel, /*implicit=*/false);
 }
 
-BridgedEffectsAttr BridgedEffectsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedEffectsKind cEffectKind) {
-  return new (cContext.unbridged()) EffectsAttr(
-      cAtLoc.unbridged(), cRange.unbridged(), unbridged(cEffectKind));
+BridgedEffectsAttr
+BridgedEffectsAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                SourceRange range,
+                                swift::EffectsKind effectKind) {
+  return new (cContext.unbridged()) EffectsAttr(atLoc, range, effectKind);
 }
 
 BridgedEffectsAttr BridgedEffectsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cCustomString,
-    BridgedSourceLoc cCustomStringLoc) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedStringRef cCustomString, SourceLoc customStringLoc) {
   return new (cContext.unbridged())
-      EffectsAttr(cAtLoc.unbridged(), cRange.unbridged(),
-                  cCustomString.unbridged(), cCustomStringLoc.unbridged());
+      EffectsAttr(atLoc, range, cCustomString.unbridged(), customStringLoc);
 }
 
 static ExclusivityAttr::Mode unbridged(BridgedExclusivityAttrMode mode) {
@@ -381,47 +298,27 @@ static ExclusivityAttr::Mode unbridged(BridgedExclusivityAttrMode mode) {
   }
   llvm_unreachable("unhandled enum value");
 }
-BridgedExclusivityAttr BridgedExclusivityAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedExclusivityAttrMode cMode) {
-  return new (cContext.unbridged())
-      ExclusivityAttr(cAtLoc.unbridged(), cRange.unbridged(), unbridged(cMode));
-}
 
-static ExposureKind unbridged(BridgedExposureKind kind) {
-  switch (kind) {
-  case BridgedExposureKindCxx:
-    return ExposureKind::Cxx;
-  case BridgedExposureKindWasm:
-    return ExposureKind::Wasm;
-  }
-  llvm_unreachable("unhandled enum value");
+BridgedExclusivityAttr
+BridgedExclusivityAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                    SourceRange range,
+                                    BridgedExclusivityAttrMode cMode) {
+  return new (cContext.unbridged())
+      ExclusivityAttr(atLoc, range, unbridged(cMode));
 }
 
 BridgedExposeAttr BridgedExposeAttr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cAtLoc,
-                                                 BridgedSourceRange cRange,
+                                                 SourceLoc atLoc,
+                                                 SourceRange range,
                                                  BridgedStringRef cName,
-                                                 BridgedExposureKind cKind) {
+                                                 swift::ExposureKind kind) {
   return new (cContext.unbridged())
-      ExposeAttr(cName.unbridged(), cAtLoc.unbridged(), cRange.unbridged(),
-                 unbridged(cKind), /*Implicit=*/false);
-}
-
-static ExternKind unbridged(BridgedExternKind kind) {
-  switch (kind) {
-  case BridgedExternKindC:
-    return ExternKind::C;
-  case BridgedExternKindWasm:
-    return ExternKind::Wasm;
-  }
-  llvm_unreachable("unhandled enum value");
+      ExposeAttr(cName.unbridged(), atLoc, range, kind, /*Implicit=*/false);
 }
 
 BridgedExternAttr BridgedExternAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedSourceLoc cLParenLoc,
-    BridgedSourceLoc cRParenLoc, BridgedExternKind cKind,
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    SourceLoc lParenLoc, SourceLoc rParenLoc, swift::ExternKind kind,
     BridgedStringRef cModuleName, BridgedStringRef cName) {
   std::optional<StringRef> moduleName = cModuleName.unbridged();
   if (moduleName->empty())
@@ -432,37 +329,24 @@ BridgedExternAttr BridgedExternAttr_createParsed(
     name = std::nullopt;
 
   return new (cContext.unbridged())
-      ExternAttr(moduleName, name, cAtLoc.unbridged(), cLParenLoc.unbridged(),
-                 cRParenLoc.unbridged(), cRange.unbridged(), unbridged(cKind),
+      ExternAttr(moduleName, name, atLoc, lParenLoc, rParenLoc, range, kind,
                  /*Implicit=*/false);
 }
 
 BridgedImplementsAttr BridgedImplementsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedTypeRepr cProtocolType,
-    BridgedDeclNameRef cMemberName, BridgedDeclNameLoc cMemberNameLoc) {
-  return ImplementsAttr::create(cContext.unbridged(), cAtLoc.unbridged(),
-                                cRange.unbridged(), cProtocolType.unbridged(),
-                                cMemberName.unbridged().getFullName(),
-                                cMemberNameLoc.unbridged());
-}
-
-static InlineKind unbridged(BridgedInlineKind kind) {
-  switch (kind) {
-  case BridgedInlineKindNever:
-    return InlineKind::Never;
-  case BridgedInlineKindAlways:
-    return InlineKind::Always;
-  }
-  llvm_unreachable("unhandled enum value");
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedTypeRepr cProtocolType, BridgedDeclNameRef cMemberName,
+    BridgedDeclNameLoc cMemberNameLoc) {
+  return ImplementsAttr::create(
+      cContext.unbridged(), atLoc, range, cProtocolType.unbridged(),
+      cMemberName.unbridged().getFullName(), cMemberNameLoc.unbridged());
 }
 
 BridgedInlineAttr BridgedInlineAttr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cAtLoc,
-                                                 BridgedSourceRange cRange,
-                                                 BridgedInlineKind cKind) {
-  return new (cContext.unbridged())
-      InlineAttr(cAtLoc.unbridged(), cRange.unbridged(), unbridged(cKind));
+                                                 SourceLoc atLoc,
+                                                 SourceRange range,
+                                                 swift::InlineKind kind) {
+  return new (cContext.unbridged()) InlineAttr(atLoc, range, kind);
 }
 
 static swift::ParsedLifetimeDependenceKind
@@ -470,10 +354,12 @@ unbridged(BridgedParsedLifetimeDependenceKind kind) {
   switch (kind) {
   case BridgedParsedLifetimeDependenceKindDefault:
     return swift::ParsedLifetimeDependenceKind::Default;
-  case BridgedParsedLifetimeDependenceKindScope:
-    return swift::ParsedLifetimeDependenceKind::Scope;
+  case BridgedParsedLifetimeDependenceKindBorrow:
+    return swift::ParsedLifetimeDependenceKind::Borrow;
   case BridgedParsedLifetimeDependenceKindInherit:
     return swift::ParsedLifetimeDependenceKind::Inherit;
+  case BridgedParsedLifetimeDependenceKindInout:
+    return swift::ParsedLifetimeDependenceKind::Inout;
   }
   llvm_unreachable("unhandled enum value");
 }
@@ -481,21 +367,19 @@ unbridged(BridgedParsedLifetimeDependenceKind kind) {
 swift::LifetimeDescriptor BridgedLifetimeDescriptor::unbridged() {
   switch (kind) {
   case DescriptorKind::Named:
-    return LifetimeDescriptor::forNamed(
-        value.name.unbridged(), ::unbridged(dependenceKind), loc.unbridged());
+    return LifetimeDescriptor::forNamed(value.name, ::unbridged(dependenceKind),
+                                        loc);
   case DescriptorKind::Ordered:
-    return LifetimeDescriptor::forOrdered(
-        value.index, ::unbridged(dependenceKind), loc.unbridged());
+    return LifetimeDescriptor::forOrdered(value.index,
+                                          ::unbridged(dependenceKind), loc);
   case DescriptorKind::Self:
-    return LifetimeDescriptor::forSelf(::unbridged(dependenceKind),
-                                       loc.unbridged());
+    return LifetimeDescriptor::forSelf(::unbridged(dependenceKind), loc);
   }
   llvm_unreachable("unhandled enum value");
 }
 
 static BridgedLifetimeEntry BridgedLifetimeEntry_createParsedImpl(
-    BridgedASTContext cContext, BridgedSourceRange cRange,
-    BridgedArrayRef cSources,
+    BridgedASTContext cContext, SourceRange range, BridgedArrayRef cSources,
     std::optional<BridgedLifetimeDescriptor> cTarget) {
   SmallVector<LifetimeDescriptor> sources;
   for (auto cSource : cSources.unbridged<BridgedLifetimeDescriptor>())
@@ -504,31 +388,32 @@ static BridgedLifetimeEntry BridgedLifetimeEntry_createParsedImpl(
   if (cTarget)
     target = cTarget->unbridged();
 
-  return LifetimeEntry::create(cContext.unbridged(), cRange.Start.unbridged(),
-                               cRange.End.unbridged(), sources, target);
+  return LifetimeEntry::create(cContext.unbridged(), range.Start, range.End,
+                               sources, target);
 }
 
 BridgedLifetimeEntry
-BridgedLifetimeEntry_createParsed(BridgedASTContext cContext,
-                                  BridgedSourceRange cRange,
+BridgedLifetimeEntry_createParsed(BridgedASTContext cContext, SourceRange range,
                                   BridgedArrayRef cSources) {
-  return BridgedLifetimeEntry_createParsedImpl(cContext, cRange, cSources,
+  return BridgedLifetimeEntry_createParsedImpl(cContext, range, cSources,
                                                std::nullopt);
 }
 
-BridgedLifetimeEntry BridgedLifetimeEntry_createParsed(
-    BridgedASTContext cContext, BridgedSourceRange cRange,
-    BridgedArrayRef cSources, BridgedLifetimeDescriptor cTarget) {
-  return BridgedLifetimeEntry_createParsedImpl(cContext, cRange, cSources,
+BridgedLifetimeEntry
+BridgedLifetimeEntry_createParsed(BridgedASTContext cContext, SourceRange range,
+                                  BridgedArrayRef cSources,
+                                  BridgedLifetimeDescriptor cTarget) {
+  return BridgedLifetimeEntry_createParsedImpl(cContext, range, cSources,
                                                cTarget);
 }
 
-BridgedLifetimeAttr BridgedLifetimeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedLifetimeEntry cEntry) {
-  return LifetimeAttr::create(cContext.unbridged(), cAtLoc.unbridged(),
-                              cRange.unbridged(), /*implicit=*/false,
-                              cEntry.unbridged());
+BridgedLifetimeAttr
+BridgedLifetimeAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                 SourceRange range, BridgedLifetimeEntry cEntry,
+                                 bool isUnderscored) {
+  return LifetimeAttr::create(cContext.unbridged(), atLoc, range,
+                              /*implicit=*/false, cEntry.unbridged(),
+                              isUnderscored);
 }
 
 BridgedMacroRole BridgedMacroRole_fromString(BridgedStringRef str) {
@@ -551,10 +436,10 @@ MacroSyntax unbridge(BridgedMacroSyntax cSyntax) {
 }
 
 BridgedMacroRoleAttr BridgedMacroRoleAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedMacroSyntax cSyntax,
-    BridgedSourceLoc cLParenLoc, BridgedMacroRole cRole, BridgedArrayRef cNames,
-    BridgedArrayRef cConformances, BridgedSourceLoc cRParenLoc) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedMacroSyntax cSyntax, SourceLoc lParenLoc, BridgedMacroRole cRole,
+    BridgedArrayRef cNames, BridgedArrayRef cConformances,
+    SourceLoc rParenLoc) {
   SmallVector<MacroIntroducedDeclName, 2> names;
   for (auto &n : cNames.unbridged<BridgedMacroIntroducedDeclName>())
     names.push_back(n.unbridged());
@@ -563,49 +448,39 @@ BridgedMacroRoleAttr BridgedMacroRoleAttr_createParsed(
   for (auto &t : cConformances.unbridged<BridgedExpr>())
     conformances.push_back(t.unbridged());
 
-  return MacroRoleAttr::create(
-      cContext.unbridged(), cAtLoc.unbridged(), cRange.unbridged(),
-      unbridge(cSyntax), cLParenLoc.unbridged(), unbridge(cRole), names,
-      conformances, cRParenLoc.unbridged(), /*implicit=*/false);
+  return MacroRoleAttr::create(cContext.unbridged(), atLoc, range,
+                               unbridge(cSyntax), lParenLoc, unbridge(cRole),
+                               names, conformances, rParenLoc,
+                               /*implicit=*/false);
 }
 
 BridgedOriginallyDefinedInAttr BridgedOriginallyDefinedInAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cModuleName,
-    BridgedPlatformKind cPlatform, BridgedVersionTuple cVersion) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedStringRef cModuleName, swift::PlatformKind platform,
+    BridgedVersionTuple cVersion) {
   return new (cContext.unbridged()) OriginallyDefinedInAttr(
-      cAtLoc.unbridged(), cRange.unbridged(), cModuleName.unbridged(),
-      unbridge(cPlatform), cVersion.unbridged(),
+      atLoc, range, cModuleName.unbridged(), platform, cVersion.unbridged(),
       /*Implicit=*/false);
 }
 
 BridgedStorageRestrictionsAttr BridgedStorageRestrictionsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedArrayRef cInitializes,
-    BridgedArrayRef cAccesses) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedArrayRef cInitializes, BridgedArrayRef cAccesses) {
   ASTContext &context = cContext.unbridged();
 
-  ArrayRef<Identifier> initializes =
-      cContext.unbridged().AllocateTransform<Identifier>(
-          cInitializes.unbridged<BridgedIdentifier>(),
-          [](auto &e) { return e.unbridged(); });
-  ArrayRef<Identifier> accesses =
-      cContext.unbridged().AllocateTransform<Identifier>(
-          cAccesses.unbridged<BridgedIdentifier>(),
-          [](auto &e) { return e.unbridged(); });
-
-  return StorageRestrictionsAttr::create(
-      context, cAtLoc.unbridged(), cRange.unbridged(), initializes, accesses);
+  auto initializes = cInitializes.unbridged<Identifier>();
+  auto accesses = cAccesses.unbridged<Identifier>();
+  return StorageRestrictionsAttr::create(context, atLoc, range, initializes,
+                                         accesses);
 }
 
 BridgedSwiftNativeObjCRuntimeBaseAttr
 BridgedSwiftNativeObjCRuntimeBaseAttr_createParsed(BridgedASTContext cContext,
-                                                   BridgedSourceLoc cAtLoc,
-                                                   BridgedSourceRange cRange,
-                                                   BridgedIdentifier cName) {
+                                                   SourceLoc atLoc,
+                                                   SourceRange range,
+                                                   Identifier name) {
   return new (cContext.unbridged())
-      SwiftNativeObjCRuntimeBaseAttr(cName.unbridged(), cAtLoc.unbridged(),
-                                     cRange.unbridged(), /*Implicit=*/false);
+      SwiftNativeObjCRuntimeBaseAttr(name, atLoc, range, /*Implicit=*/false);
 }
 
 static NonSendableKind unbridged(BridgedNonSendableKind kind) {
@@ -618,71 +493,69 @@ static NonSendableKind unbridged(BridgedNonSendableKind kind) {
   llvm_unreachable("unhandled enum value");
 }
 
-BridgedNonSendableAttr BridgedNonSendableAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNonSendableKind cKind) {
+BridgedNonSendableAttr
+BridgedNonSendableAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                    SourceRange range,
+                                    BridgedNonSendableKind cKind) {
   return new (cContext.unbridged())
-      NonSendableAttr(cAtLoc.unbridged(), cRange.unbridged(), unbridged(cKind));
+      NonSendableAttr(atLoc, range, unbridged(cKind));
 }
 
 BridgedNonisolatedAttr
-BridgedNonisolatedAttr_createParsed(BridgedASTContext cContext,
-                                    BridgedSourceLoc cAtLoc,
-                                    BridgedSourceRange cRange, bool isUnsafe) {
-  return new (cContext.unbridged()) NonisolatedAttr(
-      cAtLoc.unbridged(), cRange.unbridged(), isUnsafe, /*implicit=*/false);
+BridgedNonisolatedAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                    SourceRange range,
+                                    swift::NonIsolatedModifier modifier) {
+  return new (cContext.unbridged()) NonisolatedAttr(atLoc, range, modifier,
+                                                    /*implicit=*/false);
 }
 
-BridgedObjCAttr
-BridgedObjCAttr_createParsedUnnamed(BridgedASTContext cContext,
-                                    BridgedSourceLoc cAtLoc,
-                                    BridgedSourceLoc cAttrNameLoc) {
-  return ObjCAttr::createUnnamed(cContext.unbridged(), cAtLoc.unbridged(),
-                                 cAttrNameLoc.unbridged());
+BridgedInheritActorContextAttr BridgedInheritActorContextAttr_createParsed(
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    swift::InheritActorContextModifier modifier) {
+  return new (cContext.unbridged())
+      InheritActorContextAttr(atLoc, range, modifier,
+                              /*implicit=*/false);
 }
 
-BridgedObjCAttr BridgedObjCAttr_createParsedNullary(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cAttrNameLoc, BridgedSourceLoc cLParenLoc,
-    BridgedSourceLoc cNameLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cRParenLoc) {
-  return ObjCAttr::createNullary(cContext.unbridged(), cAtLoc.unbridged(),
-                                 cAttrNameLoc.unbridged(),
-                                 cLParenLoc.unbridged(), cNameLoc.unbridged(),
-                                 cName.unbridged(), cRParenLoc.unbridged());
+BridgedObjCAttr BridgedObjCAttr_createParsedUnnamed(BridgedASTContext cContext,
+                                                    SourceLoc atLoc,
+                                                    SourceLoc attrNameLoc) {
+  return ObjCAttr::createUnnamed(cContext.unbridged(), atLoc, attrNameLoc);
+}
+
+BridgedObjCAttr
+BridgedObjCAttr_createParsedNullary(BridgedASTContext cContext, SourceLoc atLoc,
+                                    SourceLoc attrNameLoc, SourceLoc lParenLoc,
+                                    SourceLoc nameLoc, Identifier name,
+                                    SourceLoc rParenLoc) {
+  return ObjCAttr::createNullary(cContext.unbridged(), atLoc, attrNameLoc,
+                                 lParenLoc, nameLoc, name, rParenLoc);
 }
 
 BridgedObjCAttr BridgedObjCAttr_createParsedSelector(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cAttrNameLoc, BridgedSourceLoc cLParenLoc,
-    BridgedArrayRef cNameLocs, BridgedArrayRef cNames,
-    BridgedSourceLoc cRParenLoc) {
-  SmallVector<SourceLoc> nameLocs;
-  for (auto elem : cNameLocs.unbridged<BridgedSourceLoc>())
-    nameLocs.push_back(elem.unbridged());
-  SmallVector<Identifier> names;
-  for (auto elem : cNames.unbridged<BridgedIdentifier>())
-    names.push_back(elem.unbridged());
-
-  return ObjCAttr::createSelector(
-      cContext.unbridged(), cAtLoc.unbridged(), cAttrNameLoc.unbridged(),
-      cLParenLoc.unbridged(), nameLocs, names, cRParenLoc.unbridged());
+    BridgedASTContext cContext, SourceLoc atLoc, SourceLoc attrNameLoc,
+    SourceLoc lParenLoc, BridgedArrayRef cNameLocs, BridgedArrayRef cNames,
+    SourceLoc rParenLoc) {
+  auto nameLocs = cNameLocs.unbridged<SourceLoc>();
+  auto names = cNames.unbridged<Identifier>();
+
+  return ObjCAttr::createSelector(cContext.unbridged(), atLoc, attrNameLoc,
+                                  lParenLoc, nameLocs, names, rParenLoc);
 }
 
 BridgedObjCImplementationAttr BridgedObjCImplementationAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedIdentifier cName, bool isEarlyAdopter) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    Identifier name, bool isEarlyAdopter) {
   return new (cContext.unbridged())
-      ObjCImplementationAttr(cName.unbridged(), cAtLoc.unbridged(),
-                             cRange.unbridged(), isEarlyAdopter);
+      ObjCImplementationAttr(name, atLoc, range, isEarlyAdopter);
 }
 
-BridgedObjCRuntimeNameAttr BridgedObjCRuntimeNameAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedIdentifier cName) {
+BridgedObjCRuntimeNameAttr
+BridgedObjCRuntimeNameAttr_createParsed(BridgedASTContext cContext,
+                                        SourceLoc atLoc, SourceRange range,
+                                        Identifier name) {
   return new (cContext.unbridged())
-      ObjCRuntimeNameAttr(cName.unbridged().str(), cAtLoc.unbridged(),
-                          cRange.unbridged(), /*Implicit=*/false);
+      ObjCRuntimeNameAttr(name.str(), atLoc, range, /*Implicit=*/false);
 }
 
 static OptimizationMode unbridged(BridgedOptimizationMode mode) {
@@ -697,64 +570,59 @@ static OptimizationMode unbridged(BridgedOptimizationMode mode) {
   llvm_unreachable("unhandled enum value");
 }
 
-BridgedOptimizeAttr BridgedOptimizeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedOptimizationMode cMode) {
-
+BridgedOptimizeAttr
+BridgedOptimizeAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                 SourceRange range,
+                                 BridgedOptimizationMode cMode) {
   return new (cContext.unbridged())
-      OptimizeAttr(cAtLoc.unbridged(), cRange.unbridged(), unbridged(cMode));
+      OptimizeAttr(atLoc, range, unbridged(cMode));
 }
 
 BridgedPrivateImportAttr BridgedPrivateImportAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cAttrNameLoc, BridgedSourceLoc cLParenLoc,
-    BridgedStringRef cFileName, BridgedSourceLoc cRParenLoc) {
-  return PrivateImportAttr::create(
-      cContext.unbridged(), cAtLoc.unbridged(), cAttrNameLoc.unbridged(),
-      cLParenLoc.unbridged(), cFileName.unbridged(), cRParenLoc.unbridged());
+    BridgedASTContext cContext, SourceLoc atLoc, SourceLoc attrNameLoc,
+    SourceLoc lParenLoc, BridgedStringRef cFileName, SourceLoc rParenLoc) {
+  return PrivateImportAttr::create(cContext.unbridged(), atLoc, attrNameLoc,
+                                   lParenLoc, cFileName.unbridged(), rParenLoc);
 }
 
 BridgedProjectedValuePropertyAttr
 BridgedProjectedValuePropertyAttr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAtLoc,
-                                               BridgedSourceRange cRange,
-                                               BridgedIdentifier cName) {
+                                               SourceLoc atLoc,
+                                               SourceRange range,
+                                               Identifier name) {
   return new (cContext.unbridged())
-      ProjectedValuePropertyAttr(cName.unbridged(), cAtLoc.unbridged(),
-                                 cRange.unbridged(), /*Implicit=*/false);
+      ProjectedValuePropertyAttr(name, atLoc, range, /*Implicit=*/false);
 }
 
 BridgedRawDocCommentAttr
 BridgedRawDocCommentAttr_createParsed(BridgedASTContext cContext,
-                                      BridgedCharSourceRange cRange) {
-  return new (cContext.unbridged()) RawDocCommentAttr(cRange.unbridged());
+                                      CharSourceRange range) {
+  return new (cContext.unbridged()) RawDocCommentAttr(range);
 }
 
-BridgedRawLayoutAttr BridgedStorageRestrictionsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, size_t size, size_t alignment) {
+BridgedRawLayoutAttr
+BridgedStorageRestrictionsAttr_createParsed(BridgedASTContext cContext,
+                                            SourceLoc atLoc, SourceRange range,
+                                            size_t size, size_t alignment) {
   return new (cContext.unbridged())
-      RawLayoutAttr(size, alignment, cAtLoc.unbridged(), cRange.unbridged());
+      RawLayoutAttr(size, alignment, atLoc, range);
 }
 
 SWIFT_NAME("BridgedRawLayoutAttr.createParsed(_:atLoc:range:like:moveAsLike:)")
 BridgedRawLayoutAttr BridgedStorageRestrictionsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedTypeRepr cLikeType, bool moveAsLike) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedTypeRepr cLikeType, bool moveAsLike) {
   return new (cContext.unbridged())
-      RawLayoutAttr(cLikeType.unbridged(), moveAsLike, cAtLoc.unbridged(),
-                    cRange.unbridged());
+      RawLayoutAttr(cLikeType.unbridged(), moveAsLike, atLoc, range);
 }
 
 SWIFT_NAME("BridgedRawLayoutAttr.createParsed(_:atLoc:range:likeArrayOf:count:"
            "moveAsLike:)")
 BridgedRawLayoutAttr BridgedStorageRestrictionsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedTypeRepr cLikeType,
-    BridgedTypeRepr cCountType, bool moveAsLike) {
-  return new (cContext.unbridged())
-      RawLayoutAttr(cLikeType.unbridged(), cCountType.unbridged(), moveAsLike,
-                    cAtLoc.unbridged(), cRange.unbridged());
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedTypeRepr cLikeType, BridgedTypeRepr cCountType, bool moveAsLike) {
+  return new (cContext.unbridged()) RawLayoutAttr(
+      cLikeType.unbridged(), cCountType.unbridged(), moveAsLike, atLoc, range);
 }
 
 ReferenceOwnership unbridged(BridgedReferenceOwnership kind) {
@@ -771,134 +639,124 @@ ReferenceOwnership unbridged(BridgedReferenceOwnership kind) {
   llvm_unreachable("unhandled enum value");
 }
 
-BridgedReferenceOwnershipAttr BridgedReferenceOwnershipAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedReferenceOwnership cKind) {
+BridgedReferenceOwnershipAttr
+BridgedReferenceOwnershipAttr_createParsed(BridgedASTContext cContext,
+                                           SourceLoc atLoc, SourceRange range,
+                                           BridgedReferenceOwnership cKind) {
   return new (cContext.unbridged())
-      ReferenceOwnershipAttr(cRange.unbridged(), unbridged(cKind));
+      ReferenceOwnershipAttr(range, unbridged(cKind));
 }
 
 BridgedSectionAttr BridgedSectionAttr_createParsed(BridgedASTContext cContext,
-                                                   BridgedSourceLoc cAtLoc,
-                                                   BridgedSourceRange cRange,
+                                                   SourceLoc atLoc,
+                                                   SourceRange range,
                                                    BridgedStringRef cName) {
-  return new (cContext.unbridged())
-      SectionAttr(cName.unbridged(), cAtLoc.unbridged(), cRange.unbridged(),
-                  /*Implicit=*/false);
+  return new (cContext.unbridged()) SectionAttr(cName.unbridged(), atLoc, range,
+                                                /*Implicit=*/false);
 }
 
-BridgedSemanticsAttr BridgedSemanticsAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cValue) {
+BridgedSemanticsAttr
+BridgedSemanticsAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                  SourceRange range, BridgedStringRef cValue) {
   return new (cContext.unbridged())
-      SemanticsAttr(cValue.unbridged(), cAtLoc.unbridged(), cRange.unbridged(),
+      SemanticsAttr(cValue.unbridged(), atLoc, range,
                     /*Implicit=*/false);
 }
 
 BridgedSetterAccessAttr
 BridgedSetterAccessAttr_createParsed(BridgedASTContext cContext,
-                                     BridgedSourceRange cRange,
-                                     BridgedAccessLevel cAccessLevel) {
+                                     SourceRange range,
+                                     swift::AccessLevel accessLevel) {
   return new (cContext.unbridged()) SetterAccessAttr(
-      /*atLoc=*/{}, cRange.unbridged(), unbridge(cAccessLevel).value());
+      /*atLoc=*/{}, range, accessLevel);
 }
 
 static SpecializeAttr::SpecializationKind
 unbridge(BridgedSpecializationKind kind) {
   switch (kind) {
   case BridgedSpecializationKindFull:
-    return SpecializeAttr::SpecializationKind::Full;
+    return AbstractSpecializeAttr::SpecializationKind::Full;
   case BridgedSpecializationKindPartial:
-    return SpecializeAttr::SpecializationKind::Partial;
+    return AbstractSpecializeAttr::SpecializationKind::Partial;
   }
   llvm_unreachable("unhandled kind");
 }
 
 BridgedSpecializeAttr BridgedSpecializeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNullableTrailingWhereClause cWhereClause,
-    bool exported, BridgedSpecializationKind cKind,
-    BridgedDeclNameRef cTargetFunction, BridgedArrayRef cSPIGroups,
-    BridgedArrayRef cAvailableAttrs) {
-  SmallVector<Identifier, 2> spiGroups;
-  for (auto bridging : cSPIGroups.unbridged<BridgedIdentifier>())
-    spiGroups.push_back(bridging.unbridged());
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedNullableTrailingWhereClause cWhereClause, bool exported,
+    BridgedSpecializationKind cKind, BridgedDeclNameRef cTargetFunction,
+    BridgedArrayRef cSPIGroups, BridgedArrayRef cAvailableAttrs) {
+  auto spiGroups = cSPIGroups.unbridged<Identifier>();
   SmallVector<AvailableAttr *, 2> availableAttrs;
   for (auto bridging : cAvailableAttrs.unbridged<BridgedAvailableAttr>())
     availableAttrs.push_back(bridging.unbridged());
 
   return SpecializeAttr::create(
-      cContext.unbridged(), cAtLoc.unbridged(), cRange.unbridged(),
-      cWhereClause.unbridged(), exported, unbridge(cKind),
-      cTargetFunction.unbridged(), spiGroups, availableAttrs);
+      cContext.unbridged(), atLoc, range, cWhereClause.unbridged(), exported,
+      unbridge(cKind), cTargetFunction.unbridged(), spiGroups, availableAttrs);
 }
 
-BridgedSPIAccessControlAttr BridgedSPIAccessControlAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedIdentifier cSPIGroupName) {
+BridgedSpecializedAttr BridgedSpecializedAttr_createParsed(
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedNullableTrailingWhereClause cWhereClause, bool exported,
+    BridgedSpecializationKind cKind, BridgedDeclNameRef cTargetFunction,
+    BridgedArrayRef cSPIGroups, BridgedArrayRef cAvailableAttrs) {
+  auto spiGroups = cSPIGroups.unbridged<Identifier>();
+  SmallVector<AvailableAttr *, 2> availableAttrs;
+  for (auto bridging : cAvailableAttrs.unbridged<BridgedAvailableAttr>())
+    availableAttrs.push_back(bridging.unbridged());
+
+  return SpecializedAttr::create(
+      cContext.unbridged(), atLoc, range, cWhereClause.unbridged(), exported,
+      unbridge(cKind), cTargetFunction.unbridged(), spiGroups, availableAttrs);
+}
 
-  return SPIAccessControlAttr::create(cContext.unbridged(), cAtLoc.unbridged(),
-                                      cRange.unbridged(),
-                                      cSPIGroupName.unbridged());
+BridgedSPIAccessControlAttr
+BridgedSPIAccessControlAttr_createParsed(BridgedASTContext cContext,
+                                         SourceLoc atLoc, SourceRange range,
+                                         Identifier SPIGroupName) {
+  return SPIAccessControlAttr::create(cContext.unbridged(), atLoc, range,
+                                      SPIGroupName);
 }
 
-BridgedSILGenNameAttr BridgedSILGenNameAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cName, bool isRaw) {
-  return new (cContext.unbridged())
-      SILGenNameAttr(cName.unbridged(), isRaw, cAtLoc.unbridged(),
-                     cRange.unbridged(), /*Implicit=*/false);
+BridgedSILGenNameAttr
+BridgedSILGenNameAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                   SourceRange range, BridgedStringRef cName,
+                                   bool isRaw) {
+  return new (cContext.unbridged()) SILGenNameAttr(
+      cName.unbridged(), isRaw, atLoc, range, /*Implicit=*/false);
 }
 
 BridgedTransposeAttr BridgedTransposeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedNullableTypeRepr cBaseType,
-    BridgedDeclNameRef cOriginalName, BridgedDeclNameLoc cOriginalNameLoc,
-    BridgedArrayRef cParams) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceRange range,
+    BridgedNullableTypeRepr cBaseType, BridgedDeclNameRef cOriginalName,
+    BridgedDeclNameLoc cOriginalNameLoc, BridgedArrayRef cParams) {
   SmallVector<ParsedAutoDiffParameter, 2> params;
   for (auto &elem : cParams.unbridged<BridgedParsedAutoDiffParameter>())
     params.push_back(elem.unbridged());
 
   return TransposeAttr::create(
       cContext.unbridged(),
-      /*implicit=*/false, cAtLoc.unbridged(), cRange.unbridged(),
-      cBaseType.unbridged(),
-      DeclNameRefWithLoc{cOriginalName.unbridged(), cOriginalNameLoc.unbridged(),
+      /*implicit=*/false, atLoc, range, cBaseType.unbridged(),
+      DeclNameRefWithLoc{cOriginalName.unbridged(),
+                         cOriginalNameLoc.unbridged(),
                          /*AccessorKind=*/std::nullopt},
       params);
 }
 
-BridgedTypeEraserAttr BridgedTypeEraserAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedTypeExpr cTypeExpr
-
-) {
-  return TypeEraserAttr::create(cContext.unbridged(), cAtLoc.unbridged(),
-                                cRange.unbridged(), cTypeExpr.unbridged());
+BridgedTypeEraserAttr
+BridgedTypeEraserAttr_createParsed(BridgedASTContext cContext, SourceLoc atLoc,
+                                   SourceRange range,
+                                   BridgedTypeExpr cTypeExpr) {
+  return TypeEraserAttr::create(cContext.unbridged(), atLoc, range,
+                                cTypeExpr.unbridged());
 }
 
-BridgedUnavailableFromAsyncAttr BridgedUnavailableFromAsyncAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedStringRef cMessage) {
-  return new (cContext.unbridged())
-      UnavailableFromAsyncAttr(cMessage.unbridged(), cAtLoc.unbridged(),
-                               cRange.unbridged(), /*implicit=*/false);
-}
-
-static ExecutionKind unbridged(BridgedExecutionKind kind) {
-  switch (kind) {
-  case BridgedExecutionKindConcurrent:
-    return ExecutionKind::Concurrent;
-  case BridgedExecutionKindCaller:
-    return ExecutionKind::Caller;
-  }
-  llvm_unreachable("unhandled enum value");
-}
-
-BridgedExecutionAttr BridgedExecutionAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc atLoc,
-    BridgedSourceRange range, BridgedExecutionKind behavior) {
-  return new (cContext.unbridged())
-      ExecutionAttr(atLoc.unbridged(), range.unbridged(),
-                    unbridged(behavior), /*implicit=*/false);
+BridgedUnavailableFromAsyncAttr
+BridgedUnavailableFromAsyncAttr_createParsed(BridgedASTContext cContext,
+                                             SourceLoc atLoc, SourceRange range,
+                                             BridgedStringRef cMessage) {
+  return new (cContext.unbridged()) UnavailableFromAsyncAttr(
+      cMessage.unbridged(), atLoc, range, /*implicit=*/false);
 }
diff --git a/lib/AST/Bridging/DeclBridging.cpp b/lib/AST/Bridging/DeclBridging.cpp
index bbf6b89917a0e..d826d6d4c9536 100644
--- a/lib/AST/Bridging/DeclBridging.cpp
+++ b/lib/AST/Bridging/DeclBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -32,57 +32,50 @@ using namespace swift;
 // MARK: DeclName
 //===----------------------------------------------------------------------===//
 
-BridgedDeclBaseName BridgedDeclBaseName_createConstructor() {
-  return DeclBaseName::createConstructor();
-}
+BridgedDeclNameRef BridgedDeclNameRef_createParsed(BridgedASTContext cContext,
+                                                   DeclBaseName baseName,
+                                                   BridgedArrayRef cLabels) {
+  ASTContext &context = cContext.unbridged();
+  auto labels = cLabels.unbridged<swift::Identifier>();
 
-BridgedDeclBaseName BridgedDeclBaseName_createDestructor() {
-  return DeclBaseName::createDestructor();
+  return DeclNameRef(DeclName(context, baseName, labels));
 }
 
-BridgedDeclBaseName BridgedDeclBaseName_createSubscript() {
-  return DeclBaseName::createSubscript();
+BridgedDeclNameRef BridgedDeclNameRef_createParsed(DeclBaseName baseName) {
+  return DeclNameRef(baseName);
 }
 
-BridgedDeclBaseName
-BridgedDeclBaseName_createIdentifier(BridgedIdentifier identifier) {
-  return DeclBaseName(identifier.unbridged());
+BridgedDeclNameLoc BridgedDeclNameLoc_createParsed(BridgedASTContext cContext,
+                                                   SourceLoc baseNameLoc,
+                                                   SourceLoc lParenLoc,
+                                                   BridgedArrayRef cLabelLocs,
+                                                   SourceLoc rParenLoc) {
+  return BridgedDeclNameLoc_createParsed(cContext, SourceLoc(), baseNameLoc,
+                                         lParenLoc, cLabelLocs, rParenLoc);
 }
 
-BridgedDeclNameRef
-BridgedDeclNameRef_createParsed(BridgedASTContext cContext,
-                                BridgedDeclBaseName cBaseName,
-                                BridgedArrayRef cLabels) {
+BridgedDeclNameLoc BridgedDeclNameLoc_createParsed(BridgedASTContext cContext,
+                                                   SourceLoc moduleSelectorLoc,
+                                                   SourceLoc baseNameLoc,
+                                                   SourceLoc lParenLoc,
+                                                   BridgedArrayRef cLabelLocs,
+                                                   SourceLoc rParenLoc) {
+
   ASTContext &context = cContext.unbridged();
-  SmallVector<Identifier, 4> labels;
-  for (auto &cLabel : cLabels.unbridged<BridgedIdentifier>()) {
-    labels.push_back(cLabel.unbridged());
-  }
-  return DeclNameRef(DeclName(context, cBaseName.unbridged(), labels));
-}
+  auto labelLocs = cLabelLocs.unbridged<SourceLoc>();
 
-BridgedDeclNameRef
-BridgedDeclNameRef_createParsed(BridgedDeclBaseName cBaseName) {
-  return DeclNameRef(cBaseName.unbridged());
+  return DeclNameLoc(context, moduleSelectorLoc, baseNameLoc, lParenLoc,
+                     labelLocs, rParenLoc);
 }
 
-BridgedDeclNameLoc BridgedDeclNameLoc_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cBaseNameLoc,
-    BridgedSourceLoc cLParenLoc, BridgedArrayRef cLabelLocs,
-    BridgedSourceLoc cRParenLoc) {
-
-  ASTContext &context = cContext.unbridged();
-  SmallVector<SourceLoc, 4> labelLocs;
-  for (auto &cLabelLoc : cLabelLocs.unbridged<BridgedSourceLoc>())
-    labelLocs.push_back(cLabelLoc.unbridged());
-
-  return DeclNameLoc(context, cBaseNameLoc.unbridged(), cLParenLoc.unbridged(),
-                     labelLocs, cRParenLoc.unbridged());
+BridgedDeclNameLoc BridgedDeclNameLoc_createParsed(SourceLoc baseNameLoc) {
+  return DeclNameLoc(baseNameLoc);
 }
 
-BridgedDeclNameLoc
-BridgedDeclNameLoc_createParsed(BridgedSourceLoc cBaseNameLoc) {
-  return DeclNameLoc(cBaseNameLoc.unbridged());
+BridgedDeclNameLoc BridgedDeclNameLoc_createParsed(BridgedASTContext cContext,
+                                                   SourceLoc moduleSelectorLoc,
+                                                   SourceLoc baseNameLoc) {
+  return DeclNameLoc(cContext.unbridged(), moduleSelectorLoc, baseNameLoc);
 }
 
 //===----------------------------------------------------------------------===//
@@ -111,10 +104,6 @@ static StaticSpellingKind unbridged(BridgedStaticSpelling kind) {
   return static_cast<StaticSpellingKind>(kind);
 }
 
-AccessorKind unbridged(BridgedAccessorKind kind) {
-  return static_cast<AccessorKind>(kind);
-}
-
 void BridgedDecl_attachParsedAttrs(BridgedDecl decl,
                                    BridgedDeclAttributes attrs) {
   decl.unbridged()->attachParsedAttrs(attrs.unbridged());
@@ -130,14 +119,13 @@ void BridgedDecl_forEachDeclToHoist(BridgedDecl cDecl,
 
 BridgedAccessorDecl BridgedAccessorDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedAccessorKind cKind, BridgedAbstractStorageDecl cStorage,
-    BridgedSourceLoc cDeclLoc, BridgedSourceLoc cAccessorKeywordLoc,
-    BridgedNullableParameterList cParamList, BridgedSourceLoc cAsyncLoc,
-    BridgedSourceLoc cThrowsLoc, BridgedNullableTypeRepr cThrownType) {
+    swift::AccessorKind Kind, BridgedAbstractStorageDecl cStorage,
+    SourceLoc declLoc, SourceLoc accessorKeywordLoc,
+    BridgedNullableParameterList cParamList, SourceLoc asyncLoc,
+    SourceLoc throwsLoc, BridgedNullableTypeRepr cThrownType) {
   return AccessorDecl::createParsed(
-      cContext.unbridged(), unbridged(cKind), cStorage.unbridged(),
-      cDeclLoc.unbridged(), cAccessorKeywordLoc.unbridged(),
-      cParamList.unbridged(), cAsyncLoc.unbridged(), cThrowsLoc.unbridged(),
+      cContext.unbridged(), Kind, cStorage.unbridged(), declLoc,
+      accessorKeywordLoc, cParamList.unbridged(), asyncLoc, throwsLoc,
       cThrownType.unbridged(), cDeclContext.unbridged());
 }
 
@@ -157,17 +145,15 @@ static VarDecl::Introducer unbridged(BridgedVarDeclIntroducer introducer) {
 
 BridgedPatternBindingDecl BridgedPatternBindingDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedDeclAttributes cAttrs, BridgedSourceLoc cStaticLoc,
-    BridgedStaticSpelling cStaticSpelling, BridgedSourceLoc cIntroducerLoc,
+    BridgedDeclAttributes cAttrs, SourceLoc staticLoc,
+    BridgedStaticSpelling cStaticSpelling, SourceLoc introducerLoc,
     BridgedVarDeclIntroducer cIntroducer, BridgedArrayRef cBindingEntries) {
 
   ASTContext &context = cContext.unbridged();
   DeclContext *declContext = cDeclContext.unbridged();
 
   auto introducer = unbridged(cIntroducer);
-  auto introducerLoc = cIntroducerLoc.unbridged();
   auto staticSpelling = unbridged(cStaticSpelling);
-  auto staticLoc = cStaticLoc.unbridged();
 
   SmallVector<PatternBindingEntry, 4> entries;
   for (auto &entry : cBindingEntries.unbridged<BridgedPatternBindingEntry>()) {
@@ -181,8 +167,8 @@ BridgedPatternBindingDecl BridgedPatternBindingDecl_createParsed(
       VD->setTopLevelGlobal(isa<TopLevelCodeDecl>(declContext));
     });
 
-    entries.emplace_back(pattern, entry.equalLoc.unbridged(),
-                         entry.init.unbridged(), entry.initContext.unbridged());
+    entries.emplace_back(pattern, entry.equalLoc, entry.init.unbridged(),
+                         entry.initContext.unbridged());
   }
 
   return PatternBindingDecl::create(context, staticLoc, staticSpelling,
@@ -191,15 +177,14 @@ BridgedPatternBindingDecl BridgedPatternBindingDecl_createParsed(
 
 BridgedParamDecl BridgedParamDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cSpecifierLoc, BridgedIdentifier cArgName,
-    BridgedSourceLoc cArgNameLoc, BridgedIdentifier cParamName,
-    BridgedSourceLoc cParamNameLoc, BridgedNullableExpr cDefaultArgument,
+    SourceLoc specifierLoc, swift::Identifier argName, SourceLoc argNameLoc,
+    swift::Identifier paramName, SourceLoc paramNameLoc,
+    BridgedNullableExpr cDefaultArgument,
     BridgedNullableDefaultArgumentInitializer cDefaultArgumentInitContext) {
   return ParamDecl::createParsed(
-      cContext.unbridged(), cSpecifierLoc.unbridged(), cArgNameLoc.unbridged(),
-      cArgName.unbridged(), cParamNameLoc.unbridged(), cParamName.unbridged(),
-      cDefaultArgument.unbridged(), cDefaultArgumentInitContext.unbridged(),
-      cDeclContext.unbridged());
+      cContext.unbridged(), specifierLoc, argNameLoc, argName, paramNameLoc,
+      paramName, cDefaultArgument.unbridged(),
+      cDefaultArgumentInitContext.unbridged(), cDeclContext.unbridged());
 }
 
 void BridgedConstructorDecl_setParsedBody(BridgedConstructorDecl decl,
@@ -219,25 +204,21 @@ void BridgedDestructorDecl_setParsedBody(BridgedDestructorDecl decl,
 
 BridgedFuncDecl BridgedFuncDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cStaticLoc, BridgedStaticSpelling cStaticSpelling,
-    BridgedSourceLoc cFuncKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
-    BridgedParameterList parameterList, BridgedSourceLoc cAsyncLoc,
-    BridgedSourceLoc cThrowsLoc, BridgedNullableTypeRepr thrownType,
-    BridgedNullableTypeRepr returnType,
+    SourceLoc staticLoc, BridgedStaticSpelling cStaticSpelling,
+    SourceLoc funcKeywordLoc, swift::Identifier name, SourceLoc nameLoc,
+    BridgedNullableGenericParamList genericParamList,
+    BridgedParameterList parameterList, SourceLoc asyncLoc, SourceLoc throwsLoc,
+    BridgedNullableTypeRepr thrownType, BridgedNullableTypeRepr returnType,
     BridgedNullableTrailingWhereClause genericWhereClause) {
   ASTContext &context = cContext.unbridged();
 
   auto *paramList = parameterList.unbridged();
-  auto declName = DeclName(context, cName.unbridged(), paramList);
-  auto asyncLoc = cAsyncLoc.unbridged();
-  auto throwsLoc = cThrowsLoc.unbridged();
+  auto declName = DeclName(context, name, paramList);
   // FIXME: rethrows
 
   auto *decl = FuncDecl::create(
-      context, cStaticLoc.unbridged(), unbridged(cStaticSpelling),
-      cFuncKeywordLoc.unbridged(), declName, cNameLoc.unbridged(),
-      asyncLoc.isValid(), asyncLoc, throwsLoc.isValid(), throwsLoc,
+      context, staticLoc, unbridged(cStaticSpelling), funcKeywordLoc, declName,
+      nameLoc, asyncLoc.isValid(), asyncLoc, throwsLoc.isValid(), throwsLoc,
       thrownType.unbridged(), genericParamList.unbridged(), paramList,
       returnType.unbridged(), cDeclContext.unbridged());
   decl->setTrailingWhereClause(genericWhereClause.unbridged());
@@ -247,24 +228,21 @@ BridgedFuncDecl BridgedFuncDecl_createParsed(
 
 BridgedConstructorDecl BridgedConstructorDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cInitKeywordLoc, BridgedSourceLoc cFailabilityMarkLoc,
-    bool isIUO, BridgedNullableGenericParamList genericParams,
-    BridgedParameterList bridgedParameterList, BridgedSourceLoc cAsyncLoc,
-    BridgedSourceLoc cThrowsLoc, BridgedNullableTypeRepr thrownType,
+    SourceLoc initKeywordLoc, SourceLoc failabilityMarkLoc, bool isIUO,
+    BridgedNullableGenericParamList genericParams,
+    BridgedParameterList bridgedParameterList, SourceLoc asyncLoc,
+    SourceLoc throwsLoc, BridgedNullableTypeRepr thrownType,
     BridgedNullableTrailingWhereClause genericWhereClause) {
-  assert(cFailabilityMarkLoc.unbridged().isValid() || !isIUO);
+  assert(failabilityMarkLoc.isValid() || !isIUO);
 
   ASTContext &context = cContext.unbridged();
 
   auto *parameterList = bridgedParameterList.unbridged();
   auto declName =
       DeclName(context, DeclBaseName::createConstructor(), parameterList);
-  auto asyncLoc = cAsyncLoc.unbridged();
-  auto throwsLoc = cThrowsLoc.unbridged();
-  auto failabilityMarkLoc = cFailabilityMarkLoc.unbridged();
   // FIXME: rethrows
   auto *decl = new (context) ConstructorDecl(
-      declName, cInitKeywordLoc.unbridged(), failabilityMarkLoc.isValid(),
+      declName, initKeywordLoc, failabilityMarkLoc.isValid(),
       failabilityMarkLoc, asyncLoc.isValid(), asyncLoc, throwsLoc.isValid(),
       throwsLoc, thrownType.unbridged(), parameterList,
       genericParams.unbridged(), cDeclContext.unbridged());
@@ -277,28 +255,27 @@ BridgedConstructorDecl BridgedConstructorDecl_createParsed(
 BridgedDestructorDecl
 BridgedDestructorDecl_createParsed(BridgedASTContext cContext,
                                    BridgedDeclContext cDeclContext,
-                                   BridgedSourceLoc cDeinitKeywordLoc) {
+                                   SourceLoc deinitKeywordLoc) {
   ASTContext &context = cContext.unbridged();
-  auto *decl = new (context)
-      DestructorDecl(cDeinitKeywordLoc.unbridged(), cDeclContext.unbridged());
+  auto *decl =
+      new (context) DestructorDecl(deinitKeywordLoc, cDeclContext.unbridged());
 
   return decl;
 }
 
 BridgedMacroDecl BridgedMacroDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cMacroLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList cGenericParams,
-    BridgedParameterList cParams, BridgedSourceLoc cArrowLoc,
+    SourceLoc macroLoc, swift::Identifier name, SourceLoc nameLoc,
+    BridgedNullableGenericParamList cGenericParams,
+    BridgedParameterList cParams, SourceLoc arrowLoc,
     BridgedNullableTypeRepr cResultType, BridgedNullableExpr cDefinition,
     BridgedNullableTrailingWhereClause genericWhereClause) {
   ASTContext &context = cContext.unbridged();
   auto *params = cParams.unbridged();
-  DeclName fullName = DeclName(context, cName.unbridged(), params);
+  DeclName fullName = DeclName(context, name, params);
   auto *decl = new (context)
-      MacroDecl(cMacroLoc.unbridged(), fullName, cNameLoc.unbridged(),
-                cGenericParams.unbridged(), params, cArrowLoc.unbridged(),
-                cResultType.unbridged(), cDefinition.unbridged(),
+      MacroDecl(macroLoc, fullName, nameLoc, cGenericParams.unbridged(), params,
+                arrowLoc, cResultType.unbridged(), cDefinition.unbridged(),
                 cDeclContext.unbridged());
   decl->setTrailingWhereClause(genericWhereClause.unbridged());
   return decl;
@@ -306,15 +283,14 @@ BridgedMacroDecl BridgedMacroDecl_createParsed(
 
 BridgedTypeAliasDecl BridgedTypeAliasDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cAliasKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
-    BridgedSourceLoc cEqualLoc, BridgedTypeRepr opaqueUnderlyingType,
+    SourceLoc aliasKeywordLoc, swift::Identifier name, SourceLoc nameLoc,
+    BridgedNullableGenericParamList genericParamList, SourceLoc equalLoc,
+    BridgedTypeRepr opaqueUnderlyingType,
     BridgedNullableTrailingWhereClause genericWhereClause) {
   ASTContext &context = cContext.unbridged();
 
   auto *decl = new (context)
-      TypeAliasDecl(cAliasKeywordLoc.unbridged(), cEqualLoc.unbridged(),
-                    cName.unbridged(), cNameLoc.unbridged(),
+      TypeAliasDecl(aliasKeywordLoc, equalLoc, name, nameLoc,
                     genericParamList.unbridged(), cDeclContext.unbridged());
   decl->setUnderlyingTypeRepr(opaqueUnderlyingType.unbridged());
   decl->setTrailingWhereClause(genericWhereClause.unbridged());
@@ -360,132 +336,130 @@ convertToInheritedEntries(ASTContext &ctx, BridgedArrayRef cInheritedTypes) {
 
 BridgedNominalTypeDecl BridgedEnumDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cEnumKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
+    SourceLoc enumKeywordLoc, swift::Identifier name, SourceLoc nameLoc,
+    BridgedNullableGenericParamList genericParamList,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange) {
+    SourceRange braceRange) {
   ASTContext &context = cContext.unbridged();
 
-  NominalTypeDecl *decl = new (context) EnumDecl(
-      cEnumKeywordLoc.unbridged(), cName.unbridged(), cNameLoc.unbridged(),
-      convertToInheritedEntries(context, cInheritedTypes),
-      genericParamList.unbridged(), cDeclContext.unbridged());
+  NominalTypeDecl *decl = new (context)
+      EnumDecl(enumKeywordLoc, name, nameLoc,
+               convertToInheritedEntries(context, cInheritedTypes),
+               genericParamList.unbridged(), cDeclContext.unbridged());
   decl->setTrailingWhereClause(genericWhereClause.unbridged());
-  decl->setBraces(cBraceRange.unbridged());
+  decl->setBraces(braceRange);
 
   return decl;
 }
 
 BridgedEnumCaseDecl
 BridgedEnumCaseDecl_createParsed(BridgedDeclContext cDeclContext,
-                                 BridgedSourceLoc cCaseKeywordLoc,
+                                 SourceLoc caseKeywordLoc,
                                  BridgedArrayRef cElements) {
-  return EnumCaseDecl::create(cCaseKeywordLoc.unbridged(),
+  return EnumCaseDecl::create(caseKeywordLoc,
                               cElements.unbridged<EnumElementDecl *>(),
                               cDeclContext.unbridged());
 }
 
 BridgedEnumElementDecl BridgedEnumElementDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedIdentifier cName, BridgedSourceLoc cNameLoc,
-    BridgedNullableParameterList bridgedParameterList,
-    BridgedSourceLoc cEqualsLoc, BridgedNullableExpr rawValue) {
+    swift::Identifier name, SourceLoc nameLoc,
+    BridgedNullableParameterList bridgedParameterList, SourceLoc equalsLoc,
+    BridgedNullableExpr rawValue) {
   ASTContext &context = cContext.unbridged();
 
   auto *parameterList = bridgedParameterList.unbridged();
   DeclName declName;
   {
-    auto identifier = cName.unbridged();
     if (parameterList) {
-      declName = DeclName(context, identifier, parameterList);
+      declName = DeclName(context, name, parameterList);
     } else {
-      declName = identifier;
+      declName = name;
     }
   }
 
-  return new (context) EnumElementDecl(
-      cNameLoc.unbridged(), declName, parameterList, cEqualsLoc.unbridged(),
-      cast_or_null<LiteralExpr>(rawValue.unbridged()),
-      cDeclContext.unbridged());
+  return new (context)
+      EnumElementDecl(nameLoc, declName, parameterList, equalsLoc,
+                      cast_or_null<LiteralExpr>(rawValue.unbridged()),
+                      cDeclContext.unbridged());
 }
 
 BridgedNominalTypeDecl BridgedStructDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cStructKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
+    SourceLoc structKeywordLoc, swift::Identifier name, SourceLoc nameLoc,
+    BridgedNullableGenericParamList genericParamList,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange) {
+    SourceRange braceRange) {
   ASTContext &context = cContext.unbridged();
 
-  NominalTypeDecl *decl = new (context) StructDecl(
-      cStructKeywordLoc.unbridged(), cName.unbridged(), cNameLoc.unbridged(),
-      convertToInheritedEntries(context, cInheritedTypes),
-      genericParamList.unbridged(), cDeclContext.unbridged());
+  NominalTypeDecl *decl = new (context)
+      StructDecl(structKeywordLoc, name, nameLoc,
+                 convertToInheritedEntries(context, cInheritedTypes),
+                 genericParamList.unbridged(), cDeclContext.unbridged());
   decl->setTrailingWhereClause(genericWhereClause.unbridged());
-  decl->setBraces(cBraceRange.unbridged());
+  decl->setBraces(braceRange);
 
   return decl;
 }
 
 BridgedNominalTypeDecl BridgedClassDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cClassKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableGenericParamList genericParamList,
+    SourceLoc classKeywordLoc, swift::Identifier name, SourceLoc nameLoc,
+    BridgedNullableGenericParamList genericParamList,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange, bool isActor) {
+    SourceRange braceRange, bool isActor) {
   ASTContext &context = cContext.unbridged();
 
   NominalTypeDecl *decl = new (context) ClassDecl(
-      cClassKeywordLoc.unbridged(), cName.unbridged(), cNameLoc.unbridged(),
+      classKeywordLoc, name, nameLoc,
       convertToInheritedEntries(context, cInheritedTypes),
       genericParamList.unbridged(), cDeclContext.unbridged(), isActor);
   decl->setTrailingWhereClause(genericWhereClause.unbridged());
-  decl->setBraces(cBraceRange.unbridged());
+  decl->setBraces(braceRange);
 
   return decl;
 }
 
 BridgedNominalTypeDecl BridgedProtocolDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cProtocolKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedArrayRef cPrimaryAssociatedTypeNames,
+    SourceLoc protocolKeywordLoc, swift::Identifier name, SourceLoc nameLoc,
+    BridgedArrayRef cPrimaryAssociatedTypeNames,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange) {
+    SourceRange braceRange) {
   ASTContext &context = cContext.unbridged();
 
   auto primaryAssociatedTypeNames =
       context.AllocateTransform<PrimaryAssociatedTypeName>(
           cPrimaryAssociatedTypeNames.unbridged<BridgedLocatedIdentifier>(),
           [](auto &e) -> PrimaryAssociatedTypeName {
-            return {e.Name.unbridged(), e.NameLoc.unbridged()};
+            return {e.Name, e.NameLoc};
           });
 
-  NominalTypeDecl *decl = new (context) ProtocolDecl(
-      cDeclContext.unbridged(), cProtocolKeywordLoc.unbridged(),
-      cNameLoc.unbridged(), cName.unbridged(), primaryAssociatedTypeNames,
-      convertToInheritedEntries(context, cInheritedTypes),
-      genericWhereClause.unbridged());
-  decl->setBraces(cBraceRange.unbridged());
+  NominalTypeDecl *decl = new (context)
+      ProtocolDecl(cDeclContext.unbridged(), protocolKeywordLoc, nameLoc, name,
+                   primaryAssociatedTypeNames,
+                   convertToInheritedEntries(context, cInheritedTypes),
+                   genericWhereClause.unbridged());
+  decl->setBraces(braceRange);
 
   return decl;
 }
 
 BridgedAssociatedTypeDecl BridgedAssociatedTypeDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cAssociatedtypeKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedArrayRef cInheritedTypes,
+    SourceLoc associatedtypeKeywordLoc, swift::Identifier name,
+    SourceLoc nameLoc, BridgedArrayRef cInheritedTypes,
     BridgedNullableTypeRepr defaultType,
     BridgedNullableTrailingWhereClause genericWhereClause) {
   ASTContext &context = cContext.unbridged();
 
   auto *decl = AssociatedTypeDecl::createParsed(
-      context, cDeclContext.unbridged(), cAssociatedtypeKeywordLoc.unbridged(),
-      cName.unbridged(), cNameLoc.unbridged(), defaultType.unbridged(),
-      genericWhereClause.unbridged());
+      context, cDeclContext.unbridged(), associatedtypeKeywordLoc, name,
+      nameLoc, defaultType.unbridged(), genericWhereClause.unbridged());
   decl->setInherited(convertToInheritedEntries(context, cInheritedTypes));
 
   return decl;
@@ -493,64 +467,58 @@ BridgedAssociatedTypeDecl BridgedAssociatedTypeDecl_createParsed(
 
 BridgedExtensionDecl BridgedExtensionDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cExtensionKeywordLoc, BridgedTypeRepr extendedType,
+    SourceLoc extensionKeywordLoc, BridgedTypeRepr extendedType,
     BridgedArrayRef cInheritedTypes,
     BridgedNullableTrailingWhereClause genericWhereClause,
-    BridgedSourceRange cBraceRange) {
+    SourceRange braceRange) {
   ASTContext &context = cContext.unbridged();
 
   auto *decl = ExtensionDecl::create(
-      context, cExtensionKeywordLoc.unbridged(), extendedType.unbridged(),
+      context, extensionKeywordLoc, extendedType.unbridged(),
       convertToInheritedEntries(context, cInheritedTypes),
       cDeclContext.unbridged(), genericWhereClause.unbridged());
-  decl->setBraces(cBraceRange.unbridged());
+  decl->setBraces(braceRange);
   return decl;
 }
 
 BridgedMacroExpansionDecl BridgedMacroExpansionDecl_createParsed(
-    BridgedDeclContext cDeclContext, BridgedSourceLoc cPoundLoc,
+    BridgedDeclContext cDeclContext, SourceLoc poundLoc,
     BridgedDeclNameRef cMacroNameRef, BridgedDeclNameLoc cMacroNameLoc,
-    BridgedSourceLoc cLeftAngleLoc, BridgedArrayRef cGenericArgs,
-    BridgedSourceLoc cRightAngleLoc, BridgedNullableArgumentList cArgList) {
+    SourceLoc leftAngleLoc, BridgedArrayRef cGenericArgs,
+    SourceLoc rightAngleLoc, BridgedNullableArgumentList cArgList) {
   auto *DC = cDeclContext.unbridged();
   auto &Context = DC->getASTContext();
   return MacroExpansionDecl::create(
-      cDeclContext.unbridged(), cPoundLoc.unbridged(),
-      cMacroNameRef.unbridged(), cMacroNameLoc.unbridged(),
-      cLeftAngleLoc.unbridged(),
-      Context.AllocateCopy(cGenericArgs.unbridged<TypeRepr *>()),
-      cRightAngleLoc.unbridged(), cArgList.unbridged());
+      cDeclContext.unbridged(), poundLoc, cMacroNameRef.unbridged(),
+      cMacroNameLoc.unbridged(), leftAngleLoc,
+      Context.AllocateCopy(cGenericArgs.unbridged<TypeRepr *>()), rightAngleLoc,
+      cArgList.unbridged());
 }
 
 BridgedMissingDecl BridgedMissingDecl_create(BridgedASTContext cContext,
                                              BridgedDeclContext cDeclContext,
-                                             BridgedSourceLoc cLoc) {
+                                             SourceLoc loc) {
   return MissingDecl::create(cContext.unbridged(), cDeclContext.unbridged(),
-                             cLoc.unbridged());
+                             loc);
 }
 
 BridgedOperatorDecl BridgedOperatorDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedOperatorFixity cFixity, BridgedSourceLoc cOperatorKeywordLoc,
-    BridgedIdentifier cName, BridgedSourceLoc cNameLoc,
-    BridgedSourceLoc cColonLoc, BridgedIdentifier cPrecedenceGroupName,
-    BridgedSourceLoc cPrecedenceGroupLoc) {
-  auto colonLoc = cColonLoc.unbridged();
-  assert(colonLoc.isValid() == cPrecedenceGroupName.unbridged().nonempty());
-  assert(colonLoc.isValid() == cPrecedenceGroupLoc.unbridged().isValid());
+    BridgedOperatorFixity cFixity, SourceLoc operatorKeywordLoc,
+    swift::Identifier name, SourceLoc nameLoc, SourceLoc colonLoc,
+    swift::Identifier precedenceGroupName, SourceLoc precedenceGroupLoc) {
+  assert(colonLoc.isValid() == precedenceGroupName.nonempty());
+  assert(colonLoc.isValid() == precedenceGroupLoc.isValid());
 
   ASTContext &context = cContext.unbridged();
-  auto operatorKeywordLoc = cOperatorKeywordLoc.unbridged();
-  auto name = cName.unbridged();
-  auto nameLoc = cNameLoc.unbridged();
   auto *declContext = cDeclContext.unbridged();
 
   OperatorDecl *decl = nullptr;
   switch (cFixity) {
   case BridgedOperatorFixityInfix:
-    decl = new (context) InfixOperatorDecl(
-        declContext, operatorKeywordLoc, name, nameLoc, cColonLoc.unbridged(),
-        cPrecedenceGroupName.unbridged(), cPrecedenceGroupLoc.unbridged());
+    decl = new (context)
+        InfixOperatorDecl(declContext, operatorKeywordLoc, name, nameLoc,
+                          colonLoc, precedenceGroupName, precedenceGroupLoc);
     break;
   case BridgedOperatorFixityPrefix:
     assert(colonLoc.isInvalid());
@@ -568,69 +536,72 @@ BridgedOperatorDecl BridgedOperatorDecl_createParsed(
 }
 
 BridgedPrecedenceGroupDecl BridgedPrecedenceGroupDecl_createParsed(
-    BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cPrecedencegroupKeywordLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedSourceLoc cLeftBraceLoc,
-    BridgedSourceLoc cAssociativityKeywordLoc,
-    BridgedSourceLoc cAssociativityValueLoc,
-    BridgedAssociativity cAssociativity, BridgedSourceLoc cAssignmentKeywordLoc,
-    BridgedSourceLoc cAssignmentValueLoc, bool isAssignment,
-    BridgedSourceLoc cHigherThanKeywordLoc, BridgedArrayRef cHigherThanNames,
-    BridgedSourceLoc cLowerThanKeywordLoc, BridgedArrayRef cLowerThanNames,
-    BridgedSourceLoc cRightBraceLoc) {
+    BridgedDeclContext cDeclContext, SourceLoc precedencegroupKeywordLoc,
+    swift::Identifier name, SourceLoc nameLoc, SourceLoc leftBraceLoc,
+    SourceLoc associativityKeywordLoc, SourceLoc associativityValueLoc,
+    swift::Associativity associativity, SourceLoc assignmentKeywordLoc,
+    SourceLoc assignmentValueLoc, bool isAssignment,
+    SourceLoc higherThanKeywordLoc, BridgedArrayRef cHigherThanNames,
+    SourceLoc lowerThanKeywordLoc, BridgedArrayRef cLowerThanNames,
+    SourceLoc rightBraceLoc) {
 
   SmallVector<PrecedenceGroupDecl::Relation, 2> higherThanNames;
   for (auto &pair : cHigherThanNames.unbridged<BridgedLocatedIdentifier>()) {
-    higherThanNames.push_back(
-        {pair.NameLoc.unbridged(), pair.Name.unbridged(), nullptr});
+    higherThanNames.push_back({pair.NameLoc, pair.Name, nullptr});
   }
 
   SmallVector<PrecedenceGroupDecl::Relation, 2> lowerThanNames;
   for (auto &pair : cLowerThanNames.unbridged<BridgedLocatedIdentifier>()) {
-    lowerThanNames.push_back(
-        {pair.NameLoc.unbridged(), pair.Name.unbridged(), nullptr});
+    lowerThanNames.push_back({pair.NameLoc, pair.Name, nullptr});
   }
 
   return PrecedenceGroupDecl::create(
-      cDeclContext.unbridged(), cPrecedencegroupKeywordLoc.unbridged(),
-      cNameLoc.unbridged(), cName.unbridged(), cLeftBraceLoc.unbridged(),
-      cAssociativityKeywordLoc.unbridged(), cAssociativityValueLoc.unbridged(),
-      static_cast<Associativity>(cAssociativity),
-      cAssignmentKeywordLoc.unbridged(), cAssignmentValueLoc.unbridged(),
-      isAssignment, cHigherThanKeywordLoc.unbridged(), higherThanNames,
-      cLowerThanKeywordLoc.unbridged(), lowerThanNames,
-      cRightBraceLoc.unbridged());
+      cDeclContext.unbridged(), precedencegroupKeywordLoc, nameLoc, name,
+      leftBraceLoc, associativityKeywordLoc, associativityValueLoc,
+      associativity, assignmentKeywordLoc, assignmentValueLoc, isAssignment,
+      higherThanKeywordLoc, higherThanNames, lowerThanKeywordLoc,
+      lowerThanNames, rightBraceLoc);
 }
 
 BridgedImportDecl BridgedImportDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cImportKeywordLoc, BridgedImportKind cImportKind,
-    BridgedSourceLoc cImportKindLoc, BridgedArrayRef cImportPathElements) {
+    SourceLoc importKeywordLoc, BridgedImportKind cImportKind,
+    SourceLoc importKindLoc, BridgedArrayRef cImportPathElements) {
   ImportPath::Builder builder;
   for (auto &element :
        cImportPathElements.unbridged<BridgedLocatedIdentifier>()) {
-    builder.push_back(element.Name.unbridged(), element.NameLoc.unbridged());
+    builder.push_back(element.Name, element.NameLoc);
   }
 
   ASTContext &context = cContext.unbridged();
-  return ImportDecl::create(
-      context, cDeclContext.unbridged(), cImportKeywordLoc.unbridged(),
-      static_cast<ImportKind>(cImportKind), cImportKindLoc.unbridged(),
-      std::move(builder).get());
+  return ImportDecl::create(context, cDeclContext.unbridged(), importKeywordLoc,
+                            static_cast<ImportKind>(cImportKind), importKindLoc,
+                            std::move(builder).get());
+}
+
+BridgedUsingDecl
+BridgedUsingDecl_createParsed(BridgedASTContext cContext,
+                              BridgedDeclContext cDeclContext,
+                              SourceLoc usingKeywordLoc, SourceLoc specifierLoc,
+                              BridgedUsingSpecifier specifier) {
+  ASTContext &ctx = cContext.unbridged();
+  return UsingDecl::create(ctx, usingKeywordLoc, specifierLoc,
+                           static_cast<UsingSpecifier>(specifier),
+                           cDeclContext.unbridged());
 }
 
 BridgedSubscriptDecl BridgedSubscriptDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cStaticLoc, BridgedStaticSpelling cStaticSpelling,
-    BridgedSourceLoc cSubscriptKeywordLoc,
+    SourceLoc staticLoc, BridgedStaticSpelling cStaticSpelling,
+    SourceLoc subscriptKeywordLoc,
     BridgedNullableGenericParamList cGenericParamList,
-    BridgedParameterList cParamList, BridgedSourceLoc cArrowLoc,
+    BridgedParameterList cParamList, SourceLoc arrowLoc,
     BridgedTypeRepr returnType,
     BridgedNullableTrailingWhereClause genericWhereClause) {
   auto *decl = SubscriptDecl::createParsed(
-      cContext.unbridged(), cStaticLoc.unbridged(), unbridged(cStaticSpelling),
-      cSubscriptKeywordLoc.unbridged(), cParamList.unbridged(),
-      cArrowLoc.unbridged(), returnType.unbridged(), cDeclContext.unbridged(),
+      cContext.unbridged(), staticLoc, unbridged(cStaticSpelling),
+      subscriptKeywordLoc, cParamList.unbridged(), arrowLoc,
+      returnType.unbridged(), cDeclContext.unbridged(),
       cGenericParamList.unbridged());
   decl->setTrailingWhereClause(genericWhereClause.unbridged());
   return decl;
@@ -660,9 +631,8 @@ BridgedVarDecl BridgedVarDec_createImplicitStringInterpolationVar(
 void BridgedAbstractStorageDecl_setAccessors(
     BridgedAbstractStorageDecl cStorage, BridgedAccessorRecord accessors) {
   cStorage.unbridged()->setAccessors(
-      accessors.lBraceLoc.unbridged(),
-      accessors.accessors.unbridged<AccessorDecl *>(),
-      accessors.rBraceLoc.unbridged());
+      accessors.lBraceLoc, accessors.accessors.unbridged<AccessorDecl *>(),
+      accessors.rBraceLoc);
 }
 
 //===----------------------------------------------------------------------===//
@@ -692,12 +662,12 @@ bool BridgedNominalTypeDecl_isStructWithUnreferenceableStorage(
 //===----------------------------------------------------------------------===//
 
 BridgedParameterList BridgedParameterList_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLeftParenLoc,
-    BridgedArrayRef cParameters, BridgedSourceLoc cRightParenLoc) {
+    BridgedASTContext cContext, SourceLoc leftParenLoc,
+    BridgedArrayRef cParameters, SourceLoc rightParenLoc) {
   ASTContext &context = cContext.unbridged();
-  return ParameterList::create(context, cLeftParenLoc.unbridged(),
+  return ParameterList::create(context, leftParenLoc,
                                cParameters.unbridged<ParamDecl *>(),
-                               cRightParenLoc.unbridged());
+                               rightParenLoc);
 }
 
 size_t BridgedParameterList_size(BridgedParameterList cParameterList) {
diff --git a/lib/AST/Bridging/DiagnosticsBridging.cpp b/lib/AST/Bridging/DiagnosticsBridging.cpp
index 89baf48a3f86c..6f151ae25a906 100644
--- a/lib/AST/Bridging/DiagnosticsBridging.cpp
+++ b/lib/AST/Bridging/DiagnosticsBridging.cpp
@@ -1,8 +1,8 @@
-//===--- Bridging/DiagnosticsBridging.cpp.cpp -----------------------------===//
+//===--- Bridging/DiagnosticsBridging.cpp -----------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,6 +15,7 @@
 #include "swift/AST/DiagnosticEngine.h"
 #include "swift/AST/DiagnosticsCommon.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/Basic/SourceManager.h"
 
 using namespace swift;
 
@@ -38,34 +39,29 @@ const swift::DiagnosticInfo::FixIt &unbridge(const BridgedDiagnosticFixIt &fixit
   return *reinterpret_cast<const swift::DiagnosticInfo::FixIt *>(&fixit.storage);
 }
 
-BridgedDiagnosticFixIt::BridgedDiagnosticFixIt(BridgedSourceLoc start,
-                                               uint32_t length,
+BridgedDiagnosticFixIt::BridgedDiagnosticFixIt(SourceLoc start, uint32_t length,
                                                BridgedStringRef text) {
-  DiagnosticInfo::FixIt fixit(
-          CharSourceRange(start.unbridged(), length), text.unbridged(),
-          llvm::ArrayRef<DiagnosticArgument>());
+  DiagnosticInfo::FixIt fixit(CharSourceRange(start, length), text.unbridged(),
+                              llvm::ArrayRef<DiagnosticArgument>());
   *reinterpret_cast<swift::DiagnosticInfo::FixIt *>(&storage) = fixit;
 }
 
 void BridgedDiagnosticEngine_diagnose(
-    BridgedDiagnosticEngine bridgedEngine, BridgedSourceLoc loc,
-    BridgedDiagID bridgedDiagID,
+    BridgedDiagnosticEngine bridgedEngine, SourceLoc loc, DiagID diagID,
     BridgedArrayRef /*BridgedDiagnosticArgument*/ bridgedArguments,
-    BridgedSourceLoc highlightStart, uint32_t hightlightLength,
+    SourceLoc highlightStart, uint32_t hightlightLength,
     BridgedArrayRef /*BridgedDiagnosticFixIt*/ bridgedFixIts) {
   auto *D = bridgedEngine.unbridged();
 
-  auto diagID = static_cast<DiagID>(bridgedDiagID);
   SmallVector<DiagnosticArgument, 2> arguments;
   for (auto arg : bridgedArguments.unbridged<BridgedDiagnosticArgument>()) {
     arguments.push_back(arg.unbridged());
   }
-  auto inflight = D->diagnose(loc.unbridged(), diagID, arguments);
+  auto inflight = D->diagnose(loc, diagID, arguments);
 
   // Add highlight.
-  if (highlightStart.unbridged().isValid()) {
-    CharSourceRange highlight(highlightStart.unbridged(),
-                              (unsigned)hightlightLength);
+  if (highlightStart.isValid()) {
+    CharSourceRange highlight(highlightStart, (unsigned)hightlightLength);
     inflight.highlightChars(highlight.getStart(), highlight.getEnd());
   }
 
@@ -78,6 +74,14 @@ void BridgedDiagnosticEngine_diagnose(
   }
 }
 
+SourceLoc BridgedDiagnostic_getLocationFromExternalSource(
+    BridgedDiagnosticEngine bridgedEngine, BridgedStringRef path, SwiftInt line,
+    SwiftInt column) {
+  auto *d = bridgedEngine.unbridged();
+  auto loc = d->SourceMgr.getLocFromExternalSource(path.unbridged(), line, column);
+  return loc;
+}
+
 bool BridgedDiagnosticEngine_hadAnyError(
     BridgedDiagnosticEngine bridgedEngine) {
   return bridgedEngine.unbridged()->hadAnyError();
@@ -107,31 +111,26 @@ struct BridgedDiagnostic::Impl {
   }
 };
 
-BridgedDiagnostic BridgedDiagnostic_create(BridgedSourceLoc cLoc,
+BridgedDiagnostic BridgedDiagnostic_create(SourceLoc loc,
                                            BridgedStringRef cText,
-                                           BridgedDiagnosticSeverity severity,
+                                           DiagnosticKind severity,
                                            BridgedDiagnosticEngine cDiags) {
   StringRef origText = cText.unbridged();
   BridgedDiagnostic::Impl::Allocator alloc;
   StringRef text = origText.copy(alloc);
 
-  SourceLoc loc = cLoc.unbridged();
-
   Diag<StringRef> diagID;
   switch (severity) {
-  case BridgedDiagnosticSeverity::BridgedError:
+  case DiagnosticKind::Error:
     diagID = diag::bridged_error;
     break;
-  case BridgedDiagnosticSeverity::BridgedFatalError:
-    diagID = diag::bridged_fatal_error;
-    break;
-  case BridgedDiagnosticSeverity::BridgedNote:
+  case DiagnosticKind::Note:
     diagID = diag::bridged_note;
     break;
-  case BridgedDiagnosticSeverity::BridgedRemark:
+  case DiagnosticKind::Remark:
     diagID = diag::bridged_remark;
     break;
-  case BridgedDiagnosticSeverity::BridgedWarning:
+  case DiagnosticKind::Warning:
     diagID = diag::bridged_warning;
     break;
   }
@@ -141,25 +140,16 @@ BridgedDiagnostic BridgedDiagnostic_create(BridgedSourceLoc cLoc,
 }
 
 /// Highlight a source range as part of the diagnostic.
-void BridgedDiagnostic_highlight(BridgedDiagnostic cDiag,
-                                 BridgedSourceLoc cStartLoc,
-                                 BridgedSourceLoc cEndLoc) {
-  SourceLoc startLoc = cStartLoc.unbridged();
-  SourceLoc endLoc = cEndLoc.unbridged();
-
+void BridgedDiagnostic_highlight(BridgedDiagnostic cDiag, SourceLoc startLoc,
+                                 SourceLoc endLoc) {
   BridgedDiagnostic::Impl *diag = cDiag.unbridged();
   diag->inFlight.highlightChars(startLoc, endLoc);
 }
 
 /// Add a Fix-It to replace a source range as part of the diagnostic.
-void BridgedDiagnostic_fixItReplace(BridgedDiagnostic cDiag,
-                                    BridgedSourceLoc cStartLoc,
-                                    BridgedSourceLoc cEndLoc,
+void BridgedDiagnostic_fixItReplace(BridgedDiagnostic cDiag, SourceLoc startLoc,
+                                    SourceLoc endLoc,
                                     BridgedStringRef cReplaceText) {
-
-  SourceLoc startLoc = cStartLoc.unbridged();
-  SourceLoc endLoc = cEndLoc.unbridged();
-
   StringRef origReplaceText = cReplaceText.unbridged();
   BridgedDiagnostic::Impl::Allocator alloc;
   StringRef replaceText = origReplaceText.copy(alloc);
diff --git a/lib/AST/Bridging/ExprBridging.cpp b/lib/AST/Bridging/ExprBridging.cpp
index 520076f9bee99..eb0abc5fda646 100644
--- a/lib/AST/Bridging/ExprBridging.cpp
+++ b/lib/AST/Bridging/ExprBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -39,9 +39,8 @@ BridgedArgumentList_createImplicitUnlabeled(BridgedASTContext cContext,
 }
 
 BridgedArgumentList BridgedArgumentList_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLParenLoc,
-    BridgedArrayRef cArgs, BridgedSourceLoc cRParenLoc,
-    size_t cFirstTrailingClosureIndex) {
+    BridgedASTContext cContext, SourceLoc lParenLoc, BridgedArrayRef cArgs,
+    SourceLoc rParenLoc, size_t cFirstTrailingClosureIndex) {
   SmallVector<Argument> arguments;
   arguments.reserve(cArgs.unbridged<BridgedCallArgument>().size());
   for (auto &arg : cArgs.unbridged<BridgedCallArgument>()) {
@@ -52,65 +51,58 @@ BridgedArgumentList BridgedArgumentList_createParsed(
   if (cFirstTrailingClosureIndex < arguments.size())
     firstTrailingClosureIndex = cFirstTrailingClosureIndex;
 
-  return ArgumentList::createParsed(
-      cContext.unbridged(), cLParenLoc.unbridged(), arguments,
-      cRParenLoc.unbridged(), firstTrailingClosureIndex);
+  return ArgumentList::createParsed(cContext.unbridged(), lParenLoc, arguments,
+                                    rParenLoc, firstTrailingClosureIndex);
 }
 
 BridgedArrayExpr BridgedArrayExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cLLoc,
+                                               SourceLoc lLoc,
                                                BridgedArrayRef elements,
                                                BridgedArrayRef commas,
-                                               BridgedSourceLoc cRLoc) {
+                                               SourceLoc rLoc) {
   ASTContext &context = cContext.unbridged();
-  return ArrayExpr::create(context, cLLoc.unbridged(),
-                           elements.unbridged<Expr *>(),
-                           commas.unbridged<SourceLoc>(), cRLoc.unbridged());
+  return ArrayExpr::create(context, lLoc, elements.unbridged<Expr *>(),
+                           commas.unbridged<SourceLoc>(), rLoc);
 }
 
 BridgedArrowExpr BridgedArrowExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAsyncLoc,
-                                               BridgedSourceLoc cThrowsLoc,
+                                               SourceLoc asyncLoc,
+                                               SourceLoc throwsLoc,
                                                BridgedNullableExpr cThrownType,
-                                               BridgedSourceLoc cArrowLoc) {
+                                               SourceLoc arrowLoc) {
   return new (cContext.unbridged())
-      ArrowExpr(cAsyncLoc.unbridged(), cThrowsLoc.unbridged(),
-                cThrownType.unbridged(), cArrowLoc.unbridged());
+      ArrowExpr(asyncLoc, throwsLoc, cThrownType.unbridged(), arrowLoc);
 }
 
 BridgedAssignExpr BridgedAssignExpr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cEqualsLoc) {
-  return new (cContext.unbridged()) AssignExpr(cEqualsLoc.unbridged());
+                                                 SourceLoc equalsLoc) {
+  return new (cContext.unbridged()) AssignExpr(equalsLoc);
 }
 
 BridgedAwaitExpr BridgedAwaitExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAwaitLoc,
+                                               SourceLoc awaitLoc,
                                                BridgedExpr cSubExpr) {
-  return new (cContext.unbridged())
-      AwaitExpr(cAwaitLoc.unbridged(), cSubExpr.unbridged());
+  return new (cContext.unbridged()) AwaitExpr(awaitLoc, cSubExpr.unbridged());
 }
 
-BridgedBindOptionalExpr
-BridgedBindOptionalExpr_createParsed(BridgedASTContext cContext,
-                                     BridgedExpr cSubExpr,
-                                     BridgedSourceLoc cQuestionLoc) {
+BridgedBindOptionalExpr BridgedBindOptionalExpr_createParsed(
+    BridgedASTContext cContext, BridgedExpr cSubExpr, SourceLoc questionLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context) BindOptionalExpr(cSubExpr.unbridged(),
-                                        cQuestionLoc.unbridged(), /*depth=*/0);
+  return new (context)
+      BindOptionalExpr(cSubExpr.unbridged(), questionLoc, /*depth=*/0);
 }
 
 BridgedBooleanLiteralExpr
 BridgedBooleanLiteralExpr_createParsed(BridgedASTContext cContext, bool value,
-                                       BridgedSourceLoc cTokenLoc) {
+                                       SourceLoc tokenLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context) BooleanLiteralExpr(value, cTokenLoc.unbridged());
+  return new (context) BooleanLiteralExpr(value, tokenLoc);
 }
 
 BridgedBorrowExpr BridgedBorrowExpr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cBorrowLoc,
+                                                 SourceLoc borrowLoc,
                                                  BridgedExpr cSubExpr) {
-  return new (cContext.unbridged())
-      BorrowExpr(cBorrowLoc.unbridged(), cSubExpr.unbridged());
+  return new (cContext.unbridged()) BorrowExpr(borrowLoc, cSubExpr.unbridged());
 }
 
 BridgedCallExpr BridgedCallExpr_createParsed(BridgedASTContext cContext,
@@ -123,15 +115,12 @@ BridgedCallExpr BridgedCallExpr_createParsed(BridgedASTContext cContext,
 
 BridgedCaptureListEntry BridegedCaptureListEntry_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedReferenceOwnership cOwnershipKind,
-    BridgedSourceRange cOwnershipRange, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedSourceLoc cEqualLoc,
+    BridgedReferenceOwnership cOwnershipKind, SourceRange ownershipRange,
+    Identifier name, SourceLoc nameLoc, SourceLoc equalLoc,
     BridgedExpr cInitializer) {
   return CaptureListEntry::createParsed(
-      cContext.unbridged(), unbridged(cOwnershipKind),
-      cOwnershipRange.unbridged(), cName.unbridged(), cNameLoc.unbridged(),
-      cEqualLoc.unbridged(), cInitializer.unbridged(),
-      cDeclContext.unbridged());
+      cContext.unbridged(), unbridged(cOwnershipKind), ownershipRange, name,
+      nameLoc, equalLoc, cInitializer.unbridged(), cDeclContext.unbridged());
 }
 
 BridgedCaptureListExpr
@@ -148,12 +137,12 @@ BridgedCaptureListExpr_createParsed(BridgedASTContext cContext,
 
 BridgedClosureExpr BridgedClosureExpr_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedDeclAttributes cAttributes, BridgedSourceRange cBracketRange,
+    BridgedDeclAttributes cAttributes, SourceRange bracketRange,
     BridgedNullableVarDecl cCapturedSelfDecl,
-    BridgedNullableParameterList cParameterList, BridgedSourceLoc cAsyncLoc,
-    BridgedSourceLoc cThrowsLoc, BridgedNullableTypeRepr cThrownType,
-    BridgedSourceLoc cArrowLoc, BridgedNullableTypeRepr cExplicitResultType,
-    BridgedSourceLoc cInLoc) {
+    BridgedNullableParameterList cParameterList, SourceLoc asyncLoc,
+    SourceLoc throwsLoc, BridgedNullableTypeRepr cThrownType,
+    SourceLoc arrowLoc, BridgedNullableTypeRepr cExplicitResultType,
+    SourceLoc inLoc) {
   ASTContext &context = cContext.unbridged();
   DeclContext *declContext = cDeclContext.unbridged();
   TypeExpr *throwsType = nullptr;
@@ -163,12 +152,10 @@ BridgedClosureExpr BridgedClosureExpr_createParsed(
   if (auto *tyR = cExplicitResultType.unbridged())
     explicitResultType = new (context) TypeExpr(tyR);
 
-  return new (context)
-      ClosureExpr(cAttributes.unbridged(), cBracketRange.unbridged(),
-                  cCapturedSelfDecl.unbridged(), cParameterList.unbridged(),
-                  cAsyncLoc.unbridged(), cThrowsLoc.unbridged(), throwsType,
-                  cArrowLoc.unbridged(), cInLoc.unbridged(), explicitResultType,
-                  declContext);
+  return new (context) ClosureExpr(
+      cAttributes.unbridged(), bracketRange, cCapturedSelfDecl.unbridged(),
+      cParameterList.unbridged(), asyncLoc, throwsLoc, throwsType, arrowLoc,
+      inLoc, explicitResultType, declContext);
 }
 
 BridgedParameterList
@@ -196,34 +183,31 @@ void BridgedClosureExpr_setBody(BridgedClosureExpr cClosure,
 }
 
 BridgedCoerceExpr BridgedCoerceExpr_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cAsLoc,
+                                                 SourceLoc asLoc,
                                                  BridgedTypeRepr cType) {
-  return CoerceExpr::create(cContext.unbridged(), cAsLoc.unbridged(),
-                            cType.unbridged());
+  return CoerceExpr::create(cContext.unbridged(), asLoc, cType.unbridged());
 }
 
 BridgedConditionalCheckedCastExpr
 BridgedConditionalCheckedCastExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cAsLoc,
-                                               BridgedSourceLoc cQuestionLoc,
+                                               SourceLoc asLoc,
+                                               SourceLoc questionLoc,
                                                BridgedTypeRepr cType) {
-  return ConditionalCheckedCastExpr::create(
-      cContext.unbridged(), cAsLoc.unbridged(), cQuestionLoc.unbridged(),
-      cType.unbridged());
+  return ConditionalCheckedCastExpr::create(cContext.unbridged(), asLoc,
+                                            questionLoc, cType.unbridged());
 }
 
 BridgedConsumeExpr BridgedConsumeExpr_createParsed(BridgedASTContext cContext,
-                                                   BridgedSourceLoc cConsumeLoc,
+                                                   SourceLoc consumeLoc,
                                                    BridgedExpr cSubExpr) {
   return new (cContext.unbridged())
-      ConsumeExpr(cConsumeLoc.unbridged(), cSubExpr.unbridged());
+      ConsumeExpr(consumeLoc, cSubExpr.unbridged());
 }
 
 BridgedCopyExpr BridgedCopyExpr_createParsed(BridgedASTContext cContext,
-                                             BridgedSourceLoc cCopyLoc,
+                                             SourceLoc copyLoc,
                                              BridgedExpr cSubExpr) {
-  return new (cContext.unbridged())
-      CopyExpr(cCopyLoc.unbridged(), cSubExpr.unbridged());
+  return new (cContext.unbridged()) CopyExpr(copyLoc, cSubExpr.unbridged());
 }
 
 BridgedDeclRefExpr BridgedDeclRefExpr_create(BridgedASTContext cContext,
@@ -235,131 +219,117 @@ BridgedDeclRefExpr BridgedDeclRefExpr_create(BridgedASTContext cContext,
 }
 
 BridgedDictionaryExpr BridgedDictionaryExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLBracketLoc,
+    BridgedASTContext cContext, SourceLoc lBracketLoc,
     BridgedArrayRef cElements, BridgedArrayRef cCommaLocs,
-    BridgedSourceLoc cRBracketLoc) {
-  return DictionaryExpr::create(cContext.unbridged(), cLBracketLoc.unbridged(),
+    SourceLoc rBracketLoc) {
+  return DictionaryExpr::create(cContext.unbridged(), lBracketLoc,
                                 cElements.unbridged<Expr *>(),
-                                cCommaLocs.unbridged<SourceLoc>(),
-                                cRBracketLoc.unbridged());
+                                cCommaLocs.unbridged<SourceLoc>(), rBracketLoc);
 }
 
 BridgedDiscardAssignmentExpr
 BridgedDiscardAssignmentExpr_createParsed(BridgedASTContext cContext,
-                                          BridgedSourceLoc cLoc) {
+                                          SourceLoc loc) {
   return new (cContext.unbridged())
-      DiscardAssignmentExpr(cLoc.unbridged(), /*Implicit=*/false);
+      DiscardAssignmentExpr(loc, /*Implicit=*/false);
 }
 
 BridgedDotSelfExpr BridgedDotSelfExpr_createParsed(BridgedASTContext cContext,
                                                    BridgedExpr cSubExpr,
-                                                   BridgedSourceLoc cDotLoc,
-                                                   BridgedSourceLoc cSelfLoc) {
+                                                   SourceLoc dotLoc,
+                                                   SourceLoc selfLoc) {
 
-  return new (cContext.unbridged()) DotSelfExpr(
-      cSubExpr.unbridged(), cDotLoc.unbridged(), cSelfLoc.unbridged());
+  return new (cContext.unbridged())
+      DotSelfExpr(cSubExpr.unbridged(), dotLoc, selfLoc);
 }
 
 BridgedEditorPlaceholderExpr BridgedEditorPlaceholderExpr_createParsed(
-    BridgedASTContext cContext, BridgedIdentifier cPlaceholderId,
-    BridgedSourceLoc cLoc, BridgedNullableTypeRepr cPlaceholderTyR,
+    BridgedASTContext cContext, Identifier placeholderId, SourceLoc loc,
+    BridgedNullableTypeRepr cPlaceholderTyR,
     BridgedNullableTypeRepr cExpansionTyR) {
-  return new (cContext.unbridged()) EditorPlaceholderExpr(
-      cPlaceholderId.unbridged(), cLoc.unbridged(), cPlaceholderTyR.unbridged(),
-      cExpansionTyR.unbridged());
+  return new (cContext.unbridged())
+      EditorPlaceholderExpr(placeholderId, loc, cPlaceholderTyR.unbridged(),
+                            cExpansionTyR.unbridged());
 }
 
 BridgedErrorExpr BridgedErrorExpr_create(BridgedASTContext cContext,
-                                         BridgedSourceRange cRange) {
-  return new (cContext.unbridged()) ErrorExpr(cRange.unbridged());
+                                         SourceRange range) {
+  return new (cContext.unbridged()) ErrorExpr(range);
 }
 
-BridgedForceTryExpr
-BridgedForceTryExpr_createParsed(BridgedASTContext cContext,
-                                 BridgedSourceLoc cTryLoc, BridgedExpr cSubExpr,
-                                 BridgedSourceLoc cExclaimLoc) {
-  return new (cContext.unbridged()) ForceTryExpr(
-      cTryLoc.unbridged(), cSubExpr.unbridged(), cExclaimLoc.unbridged());
+BridgedForceTryExpr BridgedForceTryExpr_createParsed(BridgedASTContext cContext,
+                                                     SourceLoc tryLoc,
+                                                     BridgedExpr cSubExpr,
+                                                     SourceLoc exclaimLoc) {
+  return new (cContext.unbridged())
+      ForceTryExpr(tryLoc, cSubExpr.unbridged(), exclaimLoc);
 }
 
 BridgedForceValueExpr
 BridgedForceValueExpr_createParsed(BridgedASTContext cContext,
-                                   BridgedExpr cSubExpr,
-                                   BridgedSourceLoc cExclaimLoc) {
+                                   BridgedExpr cSubExpr, SourceLoc exclaimLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      ForceValueExpr(cSubExpr.unbridged(), cExclaimLoc.unbridged());
+  return new (context) ForceValueExpr(cSubExpr.unbridged(), exclaimLoc);
 }
 
-BridgedFloatLiteralExpr
-BridgedFloatLiteralExpr_createParsed(BridgedASTContext cContext,
-                                     BridgedStringRef cStr,
-                                     BridgedSourceLoc cTokenLoc) {
+BridgedFloatLiteralExpr BridgedFloatLiteralExpr_createParsed(
+    BridgedASTContext cContext, BridgedStringRef cStr, SourceLoc tokenLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      FloatLiteralExpr(cStr.unbridged(), cTokenLoc.unbridged());
+  return new (context) FloatLiteralExpr(cStr.unbridged(), tokenLoc);
 }
 
-BridgedForcedCheckedCastExpr BridgedForcedCheckedCastExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAsLoc,
-    BridgedSourceLoc cExclaimLoc, BridgedTypeRepr cType) {
-  return ForcedCheckedCastExpr::create(cContext.unbridged(), cAsLoc.unbridged(),
-                                       cExclaimLoc.unbridged(),
+BridgedForcedCheckedCastExpr
+BridgedForcedCheckedCastExpr_createParsed(BridgedASTContext cContext,
+                                          SourceLoc asLoc, SourceLoc exclaimLoc,
+                                          BridgedTypeRepr cType) {
+  return ForcedCheckedCastExpr::create(cContext.unbridged(), asLoc, exclaimLoc,
                                        cType.unbridged());
 }
 
 BridgedUnresolvedSpecializeExpr BridgedUnresolvedSpecializeExpr_createParsed(
-    BridgedASTContext cContext, BridgedExpr cSubExpr,
-    BridgedSourceLoc cLAngleLoc, BridgedArrayRef cArguments,
-    BridgedSourceLoc cRAngleLoc) {
+    BridgedASTContext cContext, BridgedExpr cSubExpr, SourceLoc lAngleLoc,
+    BridgedArrayRef cArguments, SourceLoc rAngleLoc) {
   return UnresolvedSpecializeExpr::create(
-      cContext.unbridged(), cSubExpr.unbridged(), cLAngleLoc.unbridged(),
-      cArguments.unbridged<TypeRepr *>(), cRAngleLoc.unbridged());
+      cContext.unbridged(), cSubExpr.unbridged(), lAngleLoc,
+      cArguments.unbridged<TypeRepr *>(), rAngleLoc);
 }
 
 BridgedUnsafeExpr BridgedUnsafeExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cUnsafeLoc,
-                                               BridgedExpr cSubExpr) {
-  return new (cContext.unbridged())
-      UnsafeExpr(cUnsafeLoc.unbridged(), cSubExpr.unbridged());
+                                                 SourceLoc unsafeLoc,
+                                                 BridgedExpr cSubExpr) {
+  return new (cContext.unbridged()) UnsafeExpr(unsafeLoc, cSubExpr.unbridged());
 }
 
 BridgedInOutExpr BridgedInOutExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cLoc,
+                                               SourceLoc loc,
                                                BridgedExpr cSubExpr) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      InOutExpr(cLoc.unbridged(), cSubExpr.unbridged(), Type());
+  return new (context) InOutExpr(loc, cSubExpr.unbridged(), Type());
 }
 
-BridgedIntegerLiteralExpr
-BridgedIntegerLiteralExpr_createParsed(BridgedASTContext cContext,
-                                       BridgedStringRef cStr,
-                                       BridgedSourceLoc cTokenLoc) {
+BridgedIntegerLiteralExpr BridgedIntegerLiteralExpr_createParsed(
+    BridgedASTContext cContext, BridgedStringRef cStr, SourceLoc tokenLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      IntegerLiteralExpr(cStr.unbridged(), cTokenLoc.unbridged());
+  return new (context) IntegerLiteralExpr(cStr.unbridged(), tokenLoc);
 }
 
 BridgedKeyPathDotExpr
-BridgedKeyPathDotExpr_createParsed(BridgedASTContext cContext,
-                                   BridgedSourceLoc cLoc) {
-  return new (cContext.unbridged()) KeyPathDotExpr(cLoc.unbridged());
+BridgedKeyPathDotExpr_createParsed(BridgedASTContext cContext, SourceLoc loc) {
+  return new (cContext.unbridged()) KeyPathDotExpr(loc);
 }
 
 BridgedKeyPathExpr BridgedKeyPathExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cBackslashLoc,
+    BridgedASTContext cContext, SourceLoc backslashLoc,
     BridgedNullableExpr cParsedRoot, BridgedNullableExpr cParsedPath,
     bool hasLeadingDot) {
-  return KeyPathExpr::createParsed(
-      cContext.unbridged(), cBackslashLoc.unbridged(), cParsedRoot.unbridged(),
-      cParsedPath.unbridged(), hasLeadingDot);
+  return KeyPathExpr::createParsed(cContext.unbridged(), backslashLoc,
+                                   cParsedRoot.unbridged(),
+                                   cParsedPath.unbridged(), hasLeadingDot);
 }
 
 BridgedKeyPathExpr BridgedKeyPathExpr_createParsedPoundKeyPath(
-    BridgedASTContext cContext, BridgedSourceLoc cPoundLoc,
-    BridgedSourceLoc cLParenLoc, BridgedArrayRef cNames,
-    BridgedArrayRef cNameLocs, BridgedSourceLoc cRParenLoc) {
+    BridgedASTContext cContext, SourceLoc poundLoc, SourceLoc lParenLoc,
+    BridgedArrayRef cNames, BridgedArrayRef cNameLocs, SourceLoc rParenLoc) {
 
   SmallVector<KeyPathExpr::Component> components;
   auto cNameArr = cNames.unbridged<BridgedDeclNameRef>();
@@ -372,16 +342,14 @@ BridgedKeyPathExpr BridgedKeyPathExpr_createParsedPoundKeyPath(
   }
 
   return KeyPathExpr::createParsedPoundKeyPath(
-      cContext.unbridged(), cPoundLoc.unbridged(), cLParenLoc.unbridged(),
-      components, cRParenLoc.unbridged());
+      cContext.unbridged(), poundLoc, lParenLoc, components, rParenLoc);
 }
 
-BridgedSuperRefExpr
-BridgedSuperRefExpr_createParsed(BridgedASTContext cContext,
-                                 BridgedSourceLoc cSuperLoc) {
+BridgedSuperRefExpr BridgedSuperRefExpr_createParsed(BridgedASTContext cContext,
+                                                     SourceLoc superLoc) {
   ASTContext &context = cContext.unbridged();
   return new (context)
-      SuperRefExpr(/*Self=*/nullptr, cSuperLoc.unbridged(), /*Implicit=*/false);
+      SuperRefExpr(/*Self=*/nullptr, superLoc, /*Implicit=*/false);
 }
 
 BridgedSubscriptExpr
@@ -394,34 +362,31 @@ BridgedSubscriptExpr_createParsed(BridgedASTContext cContext,
 
 BridgedInterpolatedStringLiteralExpr
 BridgedInterpolatedStringLiteralExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLoc, size_t literalCapacity,
+    BridgedASTContext cContext, SourceLoc loc, size_t literalCapacity,
     size_t interpolationCount, BridgedTapExpr cAppendingExpr) {
   return new (cContext.unbridged()) InterpolatedStringLiteralExpr(
-      cLoc.unbridged(), literalCapacity, interpolationCount,
-      cAppendingExpr.unbridged());
+      loc, literalCapacity, interpolationCount, cAppendingExpr.unbridged());
 }
 
 BridgedIsExpr BridgedIsExpr_createParsed(BridgedASTContext cContext,
-                                         BridgedSourceLoc cIsLoc,
+                                         SourceLoc isLoc,
                                          BridgedTypeRepr cType) {
-  return IsExpr::create(cContext.unbridged(), cIsLoc.unbridged(),
-                        cType.unbridged());
+  return IsExpr::create(cContext.unbridged(), isLoc, cType.unbridged());
 }
 
 BridgedMacroExpansionExpr BridgedMacroExpansionExpr_createParsed(
-    BridgedDeclContext cDeclContext, BridgedSourceLoc cPoundLoc,
+    BridgedDeclContext cDeclContext, SourceLoc poundLoc,
     BridgedDeclNameRef cMacroNameRef, BridgedDeclNameLoc cMacroNameLoc,
-    BridgedSourceLoc cLeftAngleLoc, BridgedArrayRef cGenericArgs,
-    BridgedSourceLoc cRightAngleLoc, BridgedNullableArgumentList cArgList) {
+    SourceLoc leftAngleLoc, BridgedArrayRef cGenericArgs,
+    SourceLoc rightAngleLoc, BridgedNullableArgumentList cArgList) {
   auto *DC = cDeclContext.unbridged();
   auto &Context = DC->getASTContext();
   return MacroExpansionExpr::create(
-      cDeclContext.unbridged(), cPoundLoc.unbridged(),
+      cDeclContext.unbridged(), poundLoc,
       /*module name=*/DeclNameRef(), /*module name loc=*/DeclNameLoc(),
-      cMacroNameRef.unbridged(), cMacroNameLoc.unbridged(),
-      cLeftAngleLoc.unbridged(),
-      Context.AllocateCopy(cGenericArgs.unbridged<TypeRepr *>()),
-      cRightAngleLoc.unbridged(), cArgList.unbridged(),
+      cMacroNameRef.unbridged(), cMacroNameLoc.unbridged(), leftAngleLoc,
+      Context.AllocateCopy(cGenericArgs.unbridged<TypeRepr *>()), rightAngleLoc,
+      cArgList.unbridged(),
       DC->isTypeContext() ? MacroRole::Declaration
                           : getFreestandingMacroRoles());
 }
@@ -454,22 +419,21 @@ unbridge(BridgedMagicIdentifierLiteralKind cKind) {
 BridgedMagicIdentifierLiteralExpr
 BridgedMagicIdentifierLiteralExpr_createParsed(
     BridgedASTContext cContext, BridgedMagicIdentifierLiteralKind cKind,
-    BridgedSourceLoc cLoc) {
+    SourceLoc loc) {
   return new (cContext.unbridged())
-      MagicIdentifierLiteralExpr(*unbridge(cKind), cLoc.unbridged());
+      MagicIdentifierLiteralExpr(*unbridge(cKind), loc);
 }
 
 BridgedNilLiteralExpr
 BridgedNilLiteralExpr_createParsed(BridgedASTContext cContext,
-                                   BridgedSourceLoc cNilKeywordLoc) {
-  return new (cContext.unbridged()) NilLiteralExpr(cNilKeywordLoc.unbridged());
+                                   SourceLoc nilKeywordLoc) {
+  return new (cContext.unbridged()) NilLiteralExpr(nilKeywordLoc);
 }
 
 BridgedObjCSelectorExpr BridgedObjCSelectorExpr_createParsed(
     BridgedASTContext cContext, BridgedObjCSelectorKind cKind,
-    BridgedSourceLoc cKeywordLoc, BridgedSourceLoc cLParenLoc,
-    BridgedSourceLoc cModifierLoc, BridgedExpr cSubExpr,
-    BridgedSourceLoc cRParenLoc) {
+    SourceLoc keywordLoc, SourceLoc lParenLoc, SourceLoc modifierLoc,
+    BridgedExpr cSubExpr, SourceLoc rParenLoc) {
   ObjCSelectorExpr::ObjCSelectorKind kind;
   switch (cKind) {
   case BridgedObjCSelectorKindMethod:
@@ -482,9 +446,9 @@ BridgedObjCSelectorExpr BridgedObjCSelectorExpr_createParsed(
     kind = ObjCSelectorExpr::Setter;
     break;
   }
-  return new (cContext.unbridged()) ObjCSelectorExpr(
-      kind, cKeywordLoc.unbridged(), cLParenLoc.unbridged(),
-      cModifierLoc.unbridged(), cSubExpr.unbridged(), cRParenLoc.unbridged());
+  return new (cContext.unbridged())
+      ObjCSelectorExpr(kind, keywordLoc, lParenLoc, modifierLoc,
+                       cSubExpr.unbridged(), rParenLoc);
 }
 
 SWIFT_NAME("BridgedObjectLiteralKind.init(from:)")
@@ -512,33 +476,30 @@ unbridge(BridgedObjectLiteralKind kind) {
 
 SWIFT_NAME("BridgedObjectLiteralExpr.createParsed(_:poundLoc:kind:args:)")
 BridgedObjectLiteralExpr BridgedObjectLiteralExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cPoundLoc,
+    BridgedASTContext cContext, SourceLoc poundLoc,
     BridgedObjectLiteralKind cKind, BridgedArgumentList cArgs) {
-  return ObjectLiteralExpr::create(cContext.unbridged(), cPoundLoc.unbridged(),
+  return ObjectLiteralExpr::create(cContext.unbridged(), poundLoc,
                                    *unbridge(cKind), cArgs.unbridged(),
                                    /*implicit=*/false);
 }
 
-BridgedOptionalTryExpr BridgedOptionalTryExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cTryLoc, BridgedExpr cSubExpr,
-    BridgedSourceLoc cQuestionLoc) {
-  return new (cContext.unbridged()) OptionalTryExpr(
-      cTryLoc.unbridged(), cSubExpr.unbridged(), cQuestionLoc.unbridged());
+BridgedOptionalTryExpr
+BridgedOptionalTryExpr_createParsed(BridgedASTContext cContext,
+                                    SourceLoc tryLoc, BridgedExpr cSubExpr,
+                                    SourceLoc questionLoc) {
+  return new (cContext.unbridged())
+      OptionalTryExpr(tryLoc, cSubExpr.unbridged(), questionLoc);
 }
 
-BridgedPackElementExpr
-BridgedPackElementExpr_createParsed(BridgedASTContext cContext,
-                                    BridgedSourceLoc cEachLoc,
-                                    BridgedExpr cPackRefExpr) {
-  return PackElementExpr::create(cContext.unbridged(), cEachLoc.unbridged(),
+BridgedPackElementExpr BridgedPackElementExpr_createParsed(
+    BridgedASTContext cContext, SourceLoc eachLoc, BridgedExpr cPackRefExpr) {
+  return PackElementExpr::create(cContext.unbridged(), eachLoc,
                                  cPackRefExpr.unbridged());
 }
 
-BridgedPackExpansionExpr
-BridgedPackExpansionExpr_createParsed(BridgedASTContext cContext,
-                                      BridgedSourceLoc cRepeatLoc,
-                                      BridgedExpr cPatternExpr) {
-  return PackExpansionExpr::create(cContext.unbridged(), cRepeatLoc.unbridged(),
+BridgedPackExpansionExpr BridgedPackExpansionExpr_createParsed(
+    BridgedASTContext cContext, SourceLoc repeatLoc, BridgedExpr cPatternExpr) {
+  return PackExpansionExpr::create(cContext.unbridged(), repeatLoc,
                                    cPatternExpr.unbridged(),
                                    /*genericEnv=*/nullptr);
 }
@@ -558,20 +519,18 @@ BridgedPrefixUnaryExpr_createParsed(BridgedASTContext cContext,
 }
 
 BridgedRegexLiteralExpr
-BridgedRegexLiteralExpr_createParsed(BridgedASTContext cContext,
-                                     BridgedSourceLoc cLoc,
+BridgedRegexLiteralExpr_createParsed(BridgedASTContext cContext, SourceLoc loc,
                                      BridgedStringRef cRegexText) {
-  return RegexLiteralExpr::createParsed(cContext.unbridged(), cLoc.unbridged(),
+  return RegexLiteralExpr::createParsed(cContext.unbridged(), loc,
                                         cRegexText.unbridged());
 }
 
 BridgedParenExpr BridgedParenExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cLParen,
+                                               SourceLoc lParen,
                                                BridgedExpr cExpr,
-                                               BridgedSourceLoc cRParen) {
+                                               SourceLoc rParen) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      ParenExpr(cLParen.unbridged(), cExpr.unbridged(), cRParen.unbridged());
+  return new (context) ParenExpr(lParen, cExpr.unbridged(), rParen);
 }
 BridgedSequenceExpr BridgedSequenceExpr_createParsed(BridgedASTContext cContext,
                                                      BridgedArrayRef exprs) {
@@ -587,13 +546,11 @@ BridgedSingleValueStmtExpr BridgedSingleValueStmtExpr_createWithWrappedBranches(
       context, S.unbridged(), declContext, mustBeExpr);
 }
 
-BridgedStringLiteralExpr
-BridgedStringLiteralExpr_createParsed(BridgedASTContext cContext,
-                                      BridgedStringRef cStr,
-                                      BridgedSourceLoc cTokenLoc) {
+BridgedStringLiteralExpr BridgedStringLiteralExpr_createParsed(
+    BridgedASTContext cContext, BridgedStringRef cStr, SourceLoc tokenLoc) {
   ASTContext &context = cContext.unbridged();
   auto str = context.AllocateCopy(cStr.unbridged());
-  return new (context) StringLiteralExpr(str, cTokenLoc.unbridged());
+  return new (context) StringLiteralExpr(str, tokenLoc);
 }
 
 BridgedTapExpr BridgedTapExpr_create(BridgedASTContext cContext,
@@ -601,31 +558,28 @@ BridgedTapExpr BridgedTapExpr_create(BridgedASTContext cContext,
   return new (cContext.unbridged()) TapExpr(nullptr, cBody.unbridged());
 }
 
-BridgedTernaryExpr BridgedTernaryExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cQuestionLoc,
-    BridgedExpr cThenExpr, BridgedSourceLoc cColonLoc) {
-  return new (cContext.unbridged()) TernaryExpr(
-      cQuestionLoc.unbridged(), cThenExpr.unbridged(), cColonLoc.unbridged());
+BridgedTernaryExpr BridgedTernaryExpr_createParsed(BridgedASTContext cContext,
+                                                   SourceLoc questionLoc,
+                                                   BridgedExpr cThenExpr,
+                                                   SourceLoc colonLoc) {
+  return new (cContext.unbridged())
+      TernaryExpr(questionLoc, cThenExpr.unbridged(), colonLoc);
 }
 
 BridgedTryExpr BridgedTryExpr_createParsed(BridgedASTContext cContext,
-                                           BridgedSourceLoc cTryLoc,
+                                           SourceLoc tryLoc,
                                            BridgedExpr cSubExpr) {
-  return new (cContext.unbridged())
-      TryExpr(cTryLoc.unbridged(), cSubExpr.unbridged());
+  return new (cContext.unbridged()) TryExpr(tryLoc, cSubExpr.unbridged());
 }
 
-BridgedTupleExpr BridgedTupleExpr_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cLParen,
-                                               BridgedArrayRef subs,
-                                               BridgedArrayRef names,
-                                               BridgedArrayRef cNameLocs,
-                                               BridgedSourceLoc cRParen) {
+BridgedTupleExpr
+BridgedTupleExpr_createParsed(BridgedASTContext cContext, SourceLoc lParen,
+                              BridgedArrayRef subs, BridgedArrayRef names,
+                              BridgedArrayRef cNameLocs, SourceLoc rParen) {
   ASTContext &context = cContext.unbridged();
   return TupleExpr::create(
-      context, cLParen.unbridged(), subs.unbridged<Expr *>(),
-      names.unbridged<Identifier>(), cNameLocs.unbridged<SourceLoc>(),
-      cRParen.unbridged(), /*Implicit*/ false);
+      context, lParen, subs.unbridged<Expr *>(), names.unbridged<Identifier>(),
+      cNameLocs.unbridged<SourceLoc>(), rParen, /*Implicit*/ false);
 }
 
 BridgedTupleExpr BridgedTupleExpr_createParsedDictionaryElement(
@@ -663,21 +617,20 @@ BridgedUnresolvedDeclRefExpr BridgedUnresolvedDeclRefExpr_createParsed(
 }
 
 BridgedUnresolvedDotExpr BridgedUnresolvedDotExpr_createParsed(
-    BridgedASTContext cContext, BridgedExpr base, BridgedSourceLoc cDotLoc,
+    BridgedASTContext cContext, BridgedExpr base, SourceLoc dotLoc,
     BridgedDeclNameRef cName, BridgedDeclNameLoc cNameLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context) UnresolvedDotExpr(
-      base.unbridged(), cDotLoc.unbridged(), cName.unbridged(),
-      cNameLoc.unbridged(), /*isImplicit=*/false);
+  return new (context)
+      UnresolvedDotExpr(base.unbridged(), dotLoc, cName.unbridged(),
+                        cNameLoc.unbridged(), /*isImplicit=*/false);
 }
 
 BridgedUnresolvedMemberExpr BridgedUnresolvedMemberExpr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cDotLoc,
-    BridgedDeclNameRef cName, BridgedDeclNameLoc cNameLoc) {
+    BridgedASTContext cContext, SourceLoc dotLoc, BridgedDeclNameRef cName,
+    BridgedDeclNameLoc cNameLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      UnresolvedMemberExpr(cDotLoc.unbridged(), cNameLoc.unbridged(),
-                           cName.unbridged(), /*isImplicit=*/false);
+  return new (context) UnresolvedMemberExpr(
+      dotLoc, cNameLoc.unbridged(), cName.unbridged(), /*isImplicit=*/false);
 }
 
 BridgedUnresolvedPatternExpr
diff --git a/lib/AST/Bridging/GenericsBridging.cpp b/lib/AST/Bridging/GenericsBridging.cpp
index 6794eb9f89caf..15766836fd79e 100644
--- a/lib/AST/Bridging/GenericsBridging.cpp
+++ b/lib/AST/Bridging/GenericsBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -25,10 +25,10 @@ using namespace swift;
 //===----------------------------------------------------------------------===//
 
 BridgedGenericParamList BridgedGenericParamList_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLeftAngleLoc,
+    BridgedASTContext cContext, SourceLoc leftAngleLoc,
     BridgedArrayRef cParameters,
     BridgedNullableTrailingWhereClause bridgedGenericWhereClause,
-    BridgedSourceLoc cRightAngleLoc) {
+    SourceLoc rightAngleLoc) {
   SourceLoc whereLoc;
   ArrayRef<RequirementRepr> requirements;
   if (auto *genericWhereClause = bridgedGenericWhereClause.unbridged()) {
@@ -37,35 +37,18 @@ BridgedGenericParamList BridgedGenericParamList_createParsed(
   }
 
   return GenericParamList::create(
-      cContext.unbridged(), cLeftAngleLoc.unbridged(),
+      cContext.unbridged(), leftAngleLoc,
       cParameters.unbridged<GenericTypeParamDecl *>(), whereLoc, requirements,
-      cRightAngleLoc.unbridged());
+      rightAngleLoc);
 }
 
 BridgedGenericTypeParamDecl BridgedGenericTypeParamDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
-    BridgedSourceLoc cSpecifierLoc, BridgedIdentifier cName,
-    BridgedSourceLoc cNameLoc, BridgedNullableTypeRepr bridgedInheritedType,
-    size_t index, BridgedGenericTypeParamKind cParamKind) {
-  auto specifierLoc = cSpecifierLoc.unbridged();
-
-  GenericTypeParamKind paramKind;
-
-  switch (cParamKind) {
-  case BridgedGenericTypeParamKindType:
-    paramKind = GenericTypeParamKind::Type;
-    break;
-  case BridgedGenericTypeParamKindPack:
-    paramKind = GenericTypeParamKind::Pack;
-    break;
-  case BridgedGenericTypeParamKindValue:
-    paramKind = GenericTypeParamKind::Value;
-    break;
-  }
-
+    SourceLoc specifierLoc, Identifier name, SourceLoc nameLoc,
+    BridgedNullableTypeRepr bridgedInheritedType, size_t index,
+    swift::GenericTypeParamKind paramKind) {
   auto *decl = GenericTypeParamDecl::createParsed(
-      cDeclContext.unbridged(), cName.unbridged(), cNameLoc.unbridged(),
-      specifierLoc, index, paramKind);
+      cDeclContext.unbridged(), name, nameLoc, specifierLoc, index, paramKind);
 
   if (auto *inheritedType = bridgedInheritedType.unbridged()) {
     auto entry = InheritedEntry(inheritedType);
@@ -78,13 +61,12 @@ BridgedGenericTypeParamDecl BridgedGenericTypeParamDecl_createParsed(
 
 BridgedTrailingWhereClause
 BridgedTrailingWhereClause_createParsed(BridgedASTContext cContext,
-                                        BridgedSourceLoc cWhereKeywordLoc,
+                                        SourceLoc whereKeywordLoc,
                                         BridgedArrayRef cRequirements) {
   SmallVector<RequirementRepr> requirements;
   for (auto &cReq : cRequirements.unbridged<BridgedRequirementRepr>())
     requirements.push_back(cReq.unbridged());
 
-  SourceLoc whereKeywordLoc = cWhereKeywordLoc.unbridged();
   SourceLoc endLoc;
   if (requirements.empty()) {
     endLoc = whereKeywordLoc;
@@ -98,28 +80,28 @@ BridgedTrailingWhereClause_createParsed(BridgedASTContext cContext,
 
 RequirementRepr BridgedRequirementRepr::unbridged() const {
   switch (Kind) {
-  case BridgedRequirementReprKindTypeConstraint:
+  case RequirementReprKind::TypeConstraint:
     return RequirementRepr::getTypeConstraint(
-        FirstType.unbridged(), SeparatorLoc.unbridged(), SecondType.unbridged(),
+        FirstType.unbridged(), SeparatorLoc, SecondType.unbridged(),
         IsExpansionPattern);
-  case BridgedRequirementReprKindSameType:
-    return RequirementRepr::getSameType(
-        FirstType.unbridged(), SeparatorLoc.unbridged(), SecondType.unbridged(),
-        IsExpansionPattern);
-  case BridgedRequirementReprKindLayoutConstraint:
+  case RequirementReprKind::SameType:
+    return RequirementRepr::getSameType(FirstType.unbridged(), SeparatorLoc,
+                                        SecondType.unbridged(),
+                                        IsExpansionPattern);
+  case RequirementReprKind::LayoutConstraint:
     return RequirementRepr::getLayoutConstraint(
-        FirstType.unbridged(), SeparatorLoc.unbridged(),
-        {LayoutConstraint.unbridged(), LayoutConstraintLoc.unbridged()},
+        FirstType.unbridged(), SeparatorLoc,
+        {LayoutConstraint.unbridged(), LayoutConstraintLoc},
         IsExpansionPattern);
   }
 }
 
 BridgedRequirementRepr BridgedRequirementRepr_createTypeConstraint(
-    BridgedTypeRepr cSubject, BridgedSourceLoc cColonLoc,
-    BridgedTypeRepr cConstraint, bool isExpansionPattern) {
+    BridgedTypeRepr cSubject, SourceLoc colonLoc, BridgedTypeRepr cConstraint,
+    bool isExpansionPattern) {
   return {
-      /*SeparatorLoc=*/cColonLoc,
-      /*Kind=*/BridgedRequirementReprKindTypeConstraint,
+      /*SeparatorLoc=*/colonLoc,
+      /*Kind=*/RequirementReprKind::TypeConstraint,
       /*FirstType=*/cSubject,
       /*SecondType=*/cConstraint.unbridged(),
       /*LayoutConstraint=*/{},
@@ -129,11 +111,11 @@ BridgedRequirementRepr BridgedRequirementRepr_createTypeConstraint(
 }
 
 BridgedRequirementRepr BridgedRequirementRepr_createSameType(
-    BridgedTypeRepr cFirstType, BridgedSourceLoc cEqualLoc,
-    BridgedTypeRepr cSecondType, bool isExpansionPattern) {
+    BridgedTypeRepr cFirstType, SourceLoc equalLoc, BridgedTypeRepr cSecondType,
+    bool isExpansionPattern) {
   return {
-      /*SeparatorLoc=*/cEqualLoc,
-      /*Kind=*/BridgedRequirementReprKindSameType,
+      /*SeparatorLoc=*/equalLoc,
+      /*Kind=*/RequirementReprKind::SameType,
       /*FirstType=*/cFirstType,
       /*SecondType=*/cSecondType.unbridged(),
       /*LayoutConstraint=*/{},
@@ -143,85 +125,40 @@ BridgedRequirementRepr BridgedRequirementRepr_createSameType(
 }
 
 BridgedRequirementRepr BridgedRequirementRepr_createLayoutConstraint(
-    BridgedTypeRepr cSubject, BridgedSourceLoc cColonLoc,
-    BridgedLayoutConstraint cLayout, BridgedSourceLoc cLayoutLoc,
+    BridgedTypeRepr cSubject, SourceLoc colonLoc,
+    BridgedLayoutConstraint cLayout, SourceLoc layoutLoc,
     bool isExpansionPattern) {
   return {
-      /*SeparatorLoc=*/cColonLoc,
-      /*Kind=*/BridgedRequirementReprKindLayoutConstraint,
+      /*SeparatorLoc=*/colonLoc,
+      /*Kind=*/RequirementReprKind::LayoutConstraint,
       /*FirstType=*/cSubject,
       /*SecondType=*/nullptr,
       /*LayoutConstraint=*/cLayout,
-      /*LayoutConstraintLoc=*/cLayoutLoc,
+      /*LayoutConstraintLoc=*/layoutLoc,
       /*IsExpansionPattern=*/isExpansionPattern,
   };
 }
 
-static swift::LayoutConstraintKind
-unbridged(BridgedLayoutConstraintKind cKind) {
-  switch (cKind) {
-#define CASE(Kind)                                                             \
-  case BridgedLayoutConstraintKind##Kind:                                      \
-    return swift::LayoutConstraintKind::Kind;
-    CASE(UnknownLayout)
-    CASE(TrivialOfExactSize)
-    CASE(TrivialOfAtMostSize)
-    CASE(Trivial)
-    CASE(Class)
-    CASE(NativeClass)
-    CASE(RefCountedObject)
-    CASE(NativeRefCountedObject)
-    CASE(BridgeObject)
-    CASE(TrivialStride)
-#undef CASE
-  }
-}
-
-static BridgedLayoutConstraintKind bridge(swift::LayoutConstraintKind kind) {
-  switch (kind) {
-#define CASE(Kind)                                                             \
-  case swift::LayoutConstraintKind::Kind:                                      \
-    return BridgedLayoutConstraintKind##Kind;
-    CASE(UnknownLayout)
-    CASE(TrivialOfExactSize)
-    CASE(TrivialOfAtMostSize)
-    CASE(Trivial)
-    CASE(Class)
-    CASE(NativeClass)
-    CASE(RefCountedObject)
-    CASE(NativeRefCountedObject)
-    CASE(BridgeObject)
-    CASE(TrivialStride)
-#undef CASE
-  }
-}
-
 BridgedLayoutConstraint
 BridgedLayoutConstraint_getLayoutConstraint(BridgedASTContext cContext,
-                                            BridgedIdentifier cID) {
-  return swift::getLayoutConstraint(cID.unbridged(), cContext.unbridged());
+                                            Identifier ID) {
+  return swift::getLayoutConstraint(ID, cContext.unbridged());
 }
 
 BridgedLayoutConstraint
 BridgedLayoutConstraint_getLayoutConstraint(BridgedASTContext cContext,
-                                            BridgedLayoutConstraintKind cKind) {
-  return LayoutConstraint::getLayoutConstraint(unbridged(cKind),
-                                               cContext.unbridged());
+                                            swift::LayoutConstraintKind kind) {
+  return LayoutConstraint::getLayoutConstraint(kind, cContext.unbridged());
 }
 
 BridgedLayoutConstraint
 BridgedLayoutConstraint_getLayoutConstraint(BridgedASTContext cContext,
-                                            BridgedLayoutConstraintKind cKind,
+                                            swift::LayoutConstraintKind kind,
                                             size_t size, size_t alignment) {
-  return LayoutConstraint::getLayoutConstraint(unbridged(cKind), size,
-                                               alignment, cContext.unbridged());
-}
-
-BridgedLayoutConstraint BridgedLayoutConstraint_getUnknownLayout() {
-  return LayoutConstraint::getUnknownLayout();
+  return LayoutConstraint::getLayoutConstraint(kind, size, alignment,
+                                               cContext.unbridged());
 }
 
-BridgedLayoutConstraintKind
-BridgedLayoutConstraint_getKind(BridgedLayoutConstraint cConstraint) {
-  return bridge(cConstraint.unbridged()->getKind());
+swift::LayoutConstraintKind BridgedLayoutConstraint::getKind() const {
+  return unbridged()->getKind();
 }
diff --git a/lib/AST/Bridging/MiscBridging.cpp b/lib/AST/Bridging/MiscBridging.cpp
index 54fe953ff8979..3e9eff7c4015b 100644
--- a/lib/AST/Bridging/MiscBridging.cpp
+++ b/lib/AST/Bridging/MiscBridging.cpp
@@ -64,8 +64,9 @@ static SwiftMetatype declMetatypes[(unsigned)DeclKind::Last_Decl + 1];
 SwiftMetatype Decl::getDeclMetatype(DeclKind kind) {
   SwiftMetatype metatype = declMetatypes[(unsigned)kind];
   if (declMetatypesInitialized && !metatype) {
-    llvm::errs() << "Decl " << getKindName(kind) << " not registered\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Decl " << getKindName(kind) << " not registered";
+    });
   }
   return metatype;
 }
@@ -83,9 +84,9 @@ void registerBridgedDecl(BridgedStringRef bridgedClassName,
                       .Default(std::nullopt);
 
   if (!declKind) {
-    llvm::errs() << "Unknown Decl class " << bridgedClassName.unbridged()
-                 << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Unknown Decl class " << bridgedClassName.unbridged();
+    });
   }
   declMetatypes[(unsigned)declKind.value()] = metatype;
 }
diff --git a/lib/AST/Bridging/PatternBridging.cpp b/lib/AST/Bridging/PatternBridging.cpp
index 118f3ab76e94a..8665f02467cce 100644
--- a/lib/AST/Bridging/PatternBridging.cpp
+++ b/lib/AST/Bridging/PatternBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -38,8 +38,8 @@ BridgedNullableVarDecl BridgedPattern_getSingleVar(BridgedPattern cPattern) {
 }
 
 BridgedAnyPattern BridgedAnyPattern_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cLoc) {
-  return new (cContext.unbridged()) AnyPattern(cLoc.unbridged());
+                                                 SourceLoc loc) {
+  return new (cContext.unbridged()) AnyPattern(loc);
 }
 
 BridgedAnyPattern BridgedAnyPattern_createImplicit(BridgedASTContext cContext) {
@@ -48,20 +48,18 @@ BridgedAnyPattern BridgedAnyPattern_createImplicit(BridgedASTContext cContext) {
 
 BridgedBindingPattern
 BridgedBindingPattern_createParsed(BridgedASTContext cContext,
-                                   BridgedSourceLoc cKeywordLoc, bool isLet,
+                                   SourceLoc keywordLoc, bool isLet,
                                    BridgedPattern cSubPattern) {
   VarDecl::Introducer introducer =
       isLet ? VarDecl::Introducer::Let : VarDecl::Introducer::Var;
-  return BindingPattern::createParsed(cContext.unbridged(),
-                                      cKeywordLoc.unbridged(), introducer,
-                                      cSubPattern.unbridged());
+  return BindingPattern::createParsed(cContext.unbridged(), keywordLoc,
+                                      introducer, cSubPattern.unbridged());
 }
 
 BridgedBindingPattern
 BridgedBindingPattern_createImplicitCatch(BridgedDeclContext cDeclContext,
-                                          BridgedSourceLoc cLoc) {
-  return BindingPattern::createImplicitCatch(cDeclContext.unbridged(),
-                                             cLoc.unbridged());
+                                          SourceLoc loc) {
+  return BindingPattern::createImplicitCatch(cDeclContext.unbridged(), loc);
 }
 
 BridgedExprPattern
@@ -73,52 +71,51 @@ BridgedExprPattern_createParsed(BridgedDeclContext cDeclContext,
 }
 
 BridgedIsPattern BridgedIsPattern_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cIsLoc,
+                                               SourceLoc isLoc,
                                                BridgedTypeExpr cTypeExpr) {
   return new (cContext.unbridged())
-      IsPattern(cIsLoc.unbridged(), cTypeExpr.unbridged(),
+      IsPattern(isLoc, cTypeExpr.unbridged(),
                 /*subPattern=*/nullptr, CheckedCastKind::Unresolved);
 }
 
 BridgedNamedPattern
 BridgedNamedPattern_createParsed(BridgedASTContext cContext,
                                  BridgedDeclContext cDeclContext,
-                                 BridgedIdentifier name, BridgedSourceLoc loc) {
+                                 Identifier name, SourceLoc loc) {
   auto &context = cContext.unbridged();
   auto *dc = cDeclContext.unbridged();
 
   // Note 'isStatic' and the introducer value are temporary.
   // The outer context should set the correct values.
   auto *varDecl = new (context) VarDecl(
-      /*isStatic=*/false, VarDecl::Introducer::Let, loc.unbridged(),
-      name.unbridged(), dc);
+      /*isStatic=*/false, VarDecl::Introducer::Let, loc, name, dc);
   auto *pattern = new (context) NamedPattern(varDecl);
   return pattern;
 }
 
-BridgedParenPattern BridgedParenPattern_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLParenLoc,
-    BridgedPattern cSubPattern, BridgedSourceLoc cRParenLoc) {
-  return new (cContext.unbridged()) ParenPattern(
-      cLParenLoc.unbridged(), cSubPattern.unbridged(), cRParenLoc.unbridged());
+BridgedParenPattern BridgedParenPattern_createParsed(BridgedASTContext cContext,
+                                                     SourceLoc lParenLoc,
+                                                     BridgedPattern cSubPattern,
+                                                     SourceLoc rParenLoc) {
+  return new (cContext.unbridged())
+      ParenPattern(lParenLoc, cSubPattern.unbridged(), rParenLoc);
 }
 
-BridgedTuplePattern BridgedTuplePattern_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLParenLoc,
-    BridgedArrayRef cElements, BridgedSourceLoc cRParenLoc) {
+BridgedTuplePattern BridgedTuplePattern_createParsed(BridgedASTContext cContext,
+                                                     SourceLoc lParenLoc,
+                                                     BridgedArrayRef cElements,
+                                                     SourceLoc rParenLoc) {
   ASTContext &context = cContext.unbridged();
   llvm::SmallVector<TuplePatternElt, 4> elements;
   elements.reserve(cElements.Length);
   llvm::transform(cElements.unbridged<BridgedTuplePatternElt>(),
                   std::back_inserter(elements),
                   [](const BridgedTuplePatternElt &elt) {
-                    return TuplePatternElt(elt.Label.unbridged(),
-                                           elt.LabelLoc.unbridged(),
+                    return TuplePatternElt(elt.Label, elt.LabelLoc,
                                            elt.ThePattern.unbridged());
                   });
 
-  return TuplePattern::create(context, cLParenLoc.unbridged(), elements,
-                              cRParenLoc.unbridged());
+  return TuplePattern::create(context, lParenLoc, elements, rParenLoc);
 }
 
 BridgedTypedPattern BridgedTypedPattern_createParsed(BridgedASTContext cContext,
@@ -140,6 +137,6 @@ void BridgedPattern_setImplicit(BridgedPattern cPattern) {
   cPattern.unbridged()->setImplicit();
 }
 
-BridgedIdentifier BridgedPattern_getBoundName(BridgedPattern cPattern) {
+Identifier BridgedPattern_getBoundName(BridgedPattern cPattern) {
   return cPattern.unbridged()->getBoundName();
 }
diff --git a/lib/AST/Bridging/StmtBridging.cpp b/lib/AST/Bridging/StmtBridging.cpp
index 307f8fc458528..e8c11bb98d0cf 100644
--- a/lib/AST/Bridging/StmtBridging.cpp
+++ b/lib/AST/Bridging/StmtBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -45,10 +45,10 @@ BridgedStmtConditionElement_createBoolean(BridgedExpr expr) {
 }
 
 BridgedStmtConditionElement BridgedStmtConditionElement_createPatternBinding(
-    BridgedASTContext cContext, BridgedSourceLoc cIntroducerLoc,
+    BridgedASTContext cContext, SourceLoc introducerLoc,
     BridgedPattern cPattern, BridgedExpr cInitializer) {
   return StmtConditionElement(ConditionalPatternBindingInfo::create(
-      cContext.unbridged(), cIntroducerLoc.unbridged(), cPattern.unbridged(),
+      cContext.unbridged(), introducerLoc, cPattern.unbridged(),
       cInitializer.unbridged()));
 }
 
@@ -58,107 +58,98 @@ BridgedStmtConditionElement BridgedStmtConditionElement_createPoundAvailable(
 }
 
 BridgedPoundAvailableInfo BridgedPoundAvailableInfo_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cPoundLoc,
-    BridgedSourceLoc cLParenLoc, BridgedArrayRef cSpecs,
-    BridgedSourceLoc cRParenLoc, bool isUnavailability) {
+    BridgedASTContext cContext, SourceLoc poundLoc, SourceLoc lParenLoc,
+    BridgedArrayRef cSpecs, SourceLoc rParenLoc, bool isUnavailability) {
   SmallVector<AvailabilitySpec *, 4> specs;
   for (auto cSpec : cSpecs.unbridged<BridgedAvailabilitySpec>())
     specs.push_back(cSpec.unbridged());
-  return PoundAvailableInfo::create(cContext.unbridged(), cPoundLoc.unbridged(),
-                                    cLParenLoc.unbridged(), specs,
-                                    cRParenLoc.unbridged(), isUnavailability);
+  return PoundAvailableInfo::create(cContext.unbridged(), poundLoc, lParenLoc,
+                                    specs, rParenLoc, isUnavailability);
 }
 
 BridgedStmtConditionElement BridgedStmtConditionElement_createHasSymbol(
-    BridgedASTContext cContext, BridgedSourceLoc cPoundLoc,
-    BridgedSourceLoc cLParenLoc, BridgedNullableExpr cSymbolExpr,
-    BridgedSourceLoc cRParenLoc) {
-  return StmtConditionElement(PoundHasSymbolInfo::create(
-      cContext.unbridged(), cPoundLoc.unbridged(), cLParenLoc.unbridged(),
-      cSymbolExpr.unbridged(), cRParenLoc.unbridged()));
+    BridgedASTContext cContext, SourceLoc poundLoc, SourceLoc lParenLoc,
+    BridgedNullableExpr cSymbolExpr, SourceLoc rParenLoc) {
+  return StmtConditionElement(
+      PoundHasSymbolInfo::create(cContext.unbridged(), poundLoc, lParenLoc,
+                                 cSymbolExpr.unbridged(), rParenLoc));
 }
 
 BridgedBraceStmt BridgedBraceStmt_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cLBLoc,
+                                               SourceLoc lBLoc,
                                                BridgedArrayRef elements,
-                                               BridgedSourceLoc cRBLoc) {
+                                               SourceLoc rBLoc) {
   llvm::SmallVector<ASTNode, 16> nodes;
   for (auto node : elements.unbridged<BridgedASTNode>())
     nodes.push_back(node.unbridged());
 
   ASTContext &context = cContext.unbridged();
-  return BraceStmt::create(context, cLBLoc.unbridged(), nodes,
-                           cRBLoc.unbridged());
+  return BraceStmt::create(context, lBLoc, nodes, rBLoc);
 }
 
 BridgedBraceStmt BridgedBraceStmt_createImplicit(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cLBLoc,
+                                                 SourceLoc lBLoc,
                                                  BridgedASTNode element,
-                                                 BridgedSourceLoc cRBLoc) {
-  return BraceStmt::create(cContext.unbridged(), cLBLoc.unbridged(),
-                           {element.unbridged()}, cRBLoc.unbridged(),
+                                                 SourceLoc rBLoc) {
+  return BraceStmt::create(cContext.unbridged(), lBLoc, {element.unbridged()},
+                           rBLoc,
                            /*Implicit=*/true);
 }
 
 BridgedBreakStmt BridgedBreakStmt_createParsed(BridgedDeclContext cDeclContext,
-                                               BridgedSourceLoc cLoc,
-                                               BridgedIdentifier cTargetName,
-                                               BridgedSourceLoc cTargetLoc) {
+                                               SourceLoc loc,
+                                               Identifier targetName,
+                                               SourceLoc targetLoc) {
   return new (cDeclContext.unbridged()->getASTContext())
-      BreakStmt(cLoc.unbridged(), cTargetName.unbridged(),
-                cTargetLoc.unbridged(), cDeclContext.unbridged());
+      BreakStmt(loc, targetName, targetLoc, cDeclContext.unbridged());
 }
 
 static void getCaseLabelItems(BridgedArrayRef cItems,
                        SmallVectorImpl<CaseLabelItem> &output) {
   for (auto &elem : cItems.unbridged<BridgedCaseLabelItemInfo>()) {
     if (!elem.IsDefault) {
-      output.emplace_back(elem.ThePattern.unbridged(),
-                          elem.WhereLoc.unbridged(),
+      output.emplace_back(elem.ThePattern.unbridged(), elem.WhereLoc,
                           elem.GuardExpr.unbridged());
     } else {
       output.push_back(CaseLabelItem::getDefault(
-          cast<AnyPattern>(elem.ThePattern.unbridged()),
-          elem.WhereLoc.unbridged(), elem.GuardExpr.unbridged()));
+          cast<AnyPattern>(elem.ThePattern.unbridged()), elem.WhereLoc,
+          elem.GuardExpr.unbridged()));
     }
   }
 }
 
 BridgedCaseStmt BridgedCaseStmt_createParsedSwitchCase(
-    BridgedASTContext cContext, BridgedSourceLoc cIntroducerLoc,
-    BridgedArrayRef cCaseLabelItems, BridgedSourceLoc cUnknownAttrLoc,
-    BridgedSourceLoc cTerminatorLoc, BridgedBraceStmt cBody) {
+    BridgedASTContext cContext, SourceLoc introducerLoc,
+    BridgedArrayRef cCaseLabelItems, SourceLoc unknownAttrLoc,
+    SourceLoc terminatorLoc, BridgedBraceStmt cBody) {
   SmallVector<CaseLabelItem, 1> labelItems;
   getCaseLabelItems(cCaseLabelItems, labelItems);
 
-  return CaseStmt::createParsedSwitchCase(
-      cContext.unbridged(), cIntroducerLoc.unbridged(), labelItems,
-      cUnknownAttrLoc.unbridged(), cTerminatorLoc.unbridged(),
-      cBody.unbridged());
+  return CaseStmt::createParsedSwitchCase(cContext.unbridged(), introducerLoc,
+                                          labelItems, unknownAttrLoc,
+                                          terminatorLoc, cBody.unbridged());
 }
 
 BridgedCaseStmt BridgedCaseStmt_createParsedDoCatch(
-    BridgedASTContext cContext, BridgedSourceLoc cCatchLoc,
+    BridgedASTContext cContext, SourceLoc catchLoc,
     BridgedArrayRef cCaseLabelItems, BridgedBraceStmt cBody) {
   SmallVector<CaseLabelItem, 1> labelItems;
   getCaseLabelItems(cCaseLabelItems, labelItems);
 
-  return CaseStmt::createParsedDoCatch(cContext.unbridged(),
-                                       cCatchLoc.unbridged(), labelItems,
-                                       cBody.unbridged());
+  return CaseStmt::createParsedDoCatch(cContext.unbridged(), catchLoc,
+                                       labelItems, cBody.unbridged());
 }
 
-BridgedContinueStmt BridgedContinueStmt_createParsed(
-    BridgedDeclContext cDeclContext, BridgedSourceLoc cLoc,
-    BridgedIdentifier cTargetName, BridgedSourceLoc cTargetLoc) {
+BridgedContinueStmt
+BridgedContinueStmt_createParsed(BridgedDeclContext cDeclContext, SourceLoc loc,
+                                 Identifier targetName, SourceLoc targetLoc) {
   return new (cDeclContext.unbridged()->getASTContext())
-      ContinueStmt(cLoc.unbridged(), cTargetName.unbridged(),
-                   cTargetLoc.unbridged(), cDeclContext.unbridged());
+      ContinueStmt(loc, targetName, targetLoc, cDeclContext.unbridged());
 }
 
 BridgedDeferStmt BridgedDeferStmt_createParsed(BridgedDeclContext cDeclContext,
-                                               BridgedSourceLoc cDeferLoc) {
-  return DeferStmt::create(cDeclContext.unbridged(), cDeferLoc.unbridged());
+                                               SourceLoc deferLoc) {
+  return DeferStmt::create(cDeclContext.unbridged(), deferLoc);
 }
 
 BridgedFuncDecl BridgedDeferStmt_getTempDecl(BridgedDeferStmt bridged) {
@@ -166,53 +157,49 @@ BridgedFuncDecl BridgedDeferStmt_getTempDecl(BridgedDeferStmt bridged) {
 }
 
 BridgedDiscardStmt BridgedDiscardStmt_createParsed(BridgedASTContext cContext,
-                                                   BridgedSourceLoc cDiscardLoc,
+                                                   SourceLoc discardLoc,
                                                    BridgedExpr cSubExpr) {
   return new (cContext.unbridged())
-      DiscardStmt(cDiscardLoc.unbridged(), cSubExpr.unbridged());
+      DiscardStmt(discardLoc, cSubExpr.unbridged());
 }
 
 BridgedDoStmt BridgedDoStmt_createParsed(BridgedASTContext cContext,
                                          BridgedLabeledStmtInfo cLabelInfo,
-                                         BridgedSourceLoc cDoLoc,
+                                         SourceLoc doLoc,
                                          BridgedBraceStmt cBody) {
   return new (cContext.unbridged())
-      DoStmt(cLabelInfo.unbridged(), cDoLoc.unbridged(), cBody.unbridged());
+      DoStmt(cLabelInfo.unbridged(), doLoc, cBody.unbridged());
 }
 
 BridgedDoCatchStmt BridgedDoCatchStmt_createParsed(
     BridgedDeclContext cDeclContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cDoLoc, BridgedSourceLoc cThrowsLoc,
-    BridgedNullableTypeRepr cThrownType, BridgedStmt cBody,
-    BridgedArrayRef cCatches) {
+    SourceLoc doLoc, SourceLoc throwsLoc, BridgedNullableTypeRepr cThrownType,
+    BridgedStmt cBody, BridgedArrayRef cCatches) {
   return DoCatchStmt::create(cDeclContext.unbridged(), cLabelInfo.unbridged(),
-                             cDoLoc.unbridged(), cThrowsLoc.unbridged(),
-                             cThrownType.unbridged(), cBody.unbridged(),
+                             doLoc, throwsLoc, cThrownType.unbridged(),
+                             cBody.unbridged(),
                              cCatches.unbridged<CaseStmt *>());
 }
 
 BridgedFallthroughStmt
-BridgedFallthroughStmt_createParsed(BridgedSourceLoc cLoc,
-                                    BridgedDeclContext cDC) {
-  return FallthroughStmt::createParsed(cLoc.unbridged(), cDC.unbridged());
+BridgedFallthroughStmt_createParsed(SourceLoc loc, BridgedDeclContext cDC) {
+  return FallthroughStmt::createParsed(loc, cDC.unbridged());
 }
 
 BridgedForEachStmt BridgedForEachStmt_createParsed(
     BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cForLoc, BridgedSourceLoc cTryLoc,
-    BridgedSourceLoc cAwaitLoc, BridgedSourceLoc cUnsafeLoc,
-    BridgedPattern cPat, BridgedSourceLoc cInLoc,
-    BridgedExpr cSequence, BridgedSourceLoc cWhereLoc,
-    BridgedNullableExpr cWhereExpr, BridgedBraceStmt cBody) {
-  return new (cContext.unbridged()) ForEachStmt(
-      cLabelInfo.unbridged(), cForLoc.unbridged(), cTryLoc.unbridged(),
-      cAwaitLoc.unbridged(), cUnsafeLoc.unbridged(), cPat.unbridged(),
-      cInLoc.unbridged(), cSequence.unbridged(), cWhereLoc.unbridged(),
-      cWhereExpr.unbridged(), cBody.unbridged());
+    SourceLoc forLoc, SourceLoc tryLoc, SourceLoc awaitLoc, SourceLoc unsafeLoc,
+    BridgedPattern cPat, SourceLoc inLoc, BridgedExpr cSequence,
+    SourceLoc whereLoc, BridgedNullableExpr cWhereExpr,
+    BridgedBraceStmt cBody) {
+  return new (cContext.unbridged())
+      ForEachStmt(cLabelInfo.unbridged(), forLoc, tryLoc, awaitLoc, unsafeLoc,
+                  cPat.unbridged(), inLoc, cSequence.unbridged(), whereLoc,
+                  cWhereExpr.unbridged(), cBody.unbridged());
 }
 
 BridgedGuardStmt BridgedGuardStmt_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cGuardLoc,
+                                               SourceLoc guardLoc,
                                                BridgedArrayRef cConds,
                                                BridgedBraceStmt cBody) {
   auto &context = cContext.unbridged();
@@ -220,93 +207,89 @@ BridgedGuardStmt BridgedGuardStmt_createParsed(BridgedASTContext cContext,
       cConds.unbridged<BridgedStmtConditionElement>(),
       [](auto &e) { return e.unbridged(); });
 
-  return new (context)
-      GuardStmt(cGuardLoc.unbridged(), cond, cBody.unbridged());
+  return new (context) GuardStmt(guardLoc, cond, cBody.unbridged());
 }
 
-BridgedIfStmt BridgedIfStmt_createParsed(
-    BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cIfLoc, BridgedArrayRef cConds, BridgedBraceStmt cThen,
-    BridgedSourceLoc cElseLoc, BridgedNullableStmt cElse) {
+BridgedIfStmt
+BridgedIfStmt_createParsed(BridgedASTContext cContext,
+                           BridgedLabeledStmtInfo cLabelInfo, SourceLoc ifLoc,
+                           BridgedArrayRef cConds, BridgedBraceStmt cThen,
+                           SourceLoc elseLoc, BridgedNullableStmt cElse) {
   auto &context = cContext.unbridged();
   StmtCondition cond = context.AllocateTransform<StmtConditionElement>(
       cConds.unbridged<BridgedStmtConditionElement>(),
       [](auto &e) { return e.unbridged(); });
 
-  return new (context)
-      IfStmt(cLabelInfo.unbridged(), cIfLoc.unbridged(), cond,
-             cThen.unbridged(), cElseLoc.unbridged(), cElse.unbridged());
+  return new (context) IfStmt(cLabelInfo.unbridged(), ifLoc, cond,
+                              cThen.unbridged(), elseLoc, cElse.unbridged());
 }
 
 BridgedPoundAssertStmt BridgedPoundAssertStmt_createParsed(
-    BridgedASTContext cContext, BridgedSourceRange cRange,
-    BridgedExpr cConditionExpr, BridgedStringRef cMessage) {
-  return new (cContext.unbridged()) PoundAssertStmt(
-      cRange.unbridged(), cConditionExpr.unbridged(), cMessage.unbridged());
+    BridgedASTContext cContext, SourceRange range, BridgedExpr cConditionExpr,
+    BridgedStringRef cMessage) {
+  return new (cContext.unbridged())
+      PoundAssertStmt(range, cConditionExpr.unbridged(), cMessage.unbridged());
 }
 
-BridgedRepeatWhileStmt BridgedRepeatWhileStmt_createParsed(
-    BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cRepeatLoc, BridgedExpr cCond, BridgedSourceLoc cWhileLoc,
-    BridgedStmt cBody) {
-  return new (cContext.unbridged()) RepeatWhileStmt(
-      cLabelInfo.unbridged(), cRepeatLoc.unbridged(), cCond.unbridged(),
-      cWhileLoc.unbridged(), cBody.unbridged());
+BridgedRepeatWhileStmt
+BridgedRepeatWhileStmt_createParsed(BridgedASTContext cContext,
+                                    BridgedLabeledStmtInfo cLabelInfo,
+                                    SourceLoc repeatLoc, BridgedExpr cCond,
+                                    SourceLoc whileLoc, BridgedStmt cBody) {
+  return new (cContext.unbridged())
+      RepeatWhileStmt(cLabelInfo.unbridged(), repeatLoc, cCond.unbridged(),
+                      whileLoc, cBody.unbridged());
 }
 
 BridgedReturnStmt BridgedReturnStmt_createParsed(BridgedASTContext cContext,
-                                                 BridgedSourceLoc cLoc,
+                                                 SourceLoc loc,
                                                  BridgedNullableExpr expr) {
   ASTContext &context = cContext.unbridged();
-  return ReturnStmt::createParsed(context, cLoc.unbridged(), expr.unbridged());
+  return ReturnStmt::createParsed(context, loc, expr.unbridged());
 }
 
 BridgedSwitchStmt BridgedSwitchStmt_createParsed(
     BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cSwitchLoc, BridgedExpr cSubjectExpr,
-    BridgedSourceLoc cLBraceLoc, BridgedArrayRef cCases,
-    BridgedSourceLoc cRBraceLoc) {
+    SourceLoc switchLoc, BridgedExpr cSubjectExpr, SourceLoc lBraceLoc,
+    BridgedArrayRef cCases, SourceLoc rBraceLoc) {
   SmallVector<CaseStmt *, 16> cases;
   for (auto cCase : cCases.unbridged<BridgedCaseStmt>())
     cases.push_back(cCase.unbridged());
-  return SwitchStmt::create(cLabelInfo.unbridged(), cSwitchLoc.unbridged(),
-                            cSubjectExpr.unbridged(), cLBraceLoc.unbridged(),
-                            cases, cRBraceLoc.unbridged(),
-                            cRBraceLoc.unbridged(), cContext.unbridged());
+  return SwitchStmt::create(cLabelInfo.unbridged(), switchLoc,
+                            cSubjectExpr.unbridged(), lBraceLoc, cases,
+                            rBraceLoc, rBraceLoc, cContext.unbridged());
 }
 
 BridgedThenStmt BridgedThenStmt_createParsed(BridgedASTContext cContext,
-                                             BridgedSourceLoc cThenLoc,
+                                             SourceLoc thenLoc,
                                              BridgedExpr cResult) {
-  return ThenStmt::createParsed(cContext.unbridged(), cThenLoc.unbridged(),
+  return ThenStmt::createParsed(cContext.unbridged(), thenLoc,
                                 cResult.unbridged());
 }
 
 BridgedThrowStmt BridgedThrowStmt_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cThrowLoc,
+                                               SourceLoc throwLoc,
                                                BridgedExpr cSubExpr) {
-  return new (cContext.unbridged())
-      ThrowStmt(cThrowLoc.unbridged(), cSubExpr.unbridged());
+  return new (cContext.unbridged()) ThrowStmt(throwLoc, cSubExpr.unbridged());
 }
 
 BridgedWhileStmt BridgedWhileStmt_createParsed(
     BridgedASTContext cContext, BridgedLabeledStmtInfo cLabelInfo,
-    BridgedSourceLoc cWhileLoc, BridgedArrayRef cCond, BridgedStmt cBody) {
+    SourceLoc whileLoc, BridgedArrayRef cCond, BridgedStmt cBody) {
   auto &context = cContext.unbridged();
   StmtCondition cond = context.AllocateTransform<StmtConditionElement>(
       cCond.unbridged<BridgedStmtConditionElement>(),
       [](auto &e) { return e.unbridged(); });
 
-  return new (cContext.unbridged()) WhileStmt(
-      cLabelInfo.unbridged(), cWhileLoc.unbridged(), cond, cBody.unbridged());
+  return new (cContext.unbridged())
+      WhileStmt(cLabelInfo.unbridged(), whileLoc, cond, cBody.unbridged());
 }
 
 BridgedYieldStmt BridgedYieldStmt_createParsed(BridgedASTContext cContext,
-                                               BridgedSourceLoc cYieldLoc,
-                                               BridgedSourceLoc cLParenLoc,
+                                               SourceLoc yieldLoc,
+                                               SourceLoc lParenLoc,
                                                BridgedArrayRef cYields,
-                                               BridgedSourceLoc cRParenLoc) {
-  return YieldStmt::create(cContext.unbridged(), cYieldLoc.unbridged(),
-                           cLParenLoc.unbridged(), cYields.unbridged<Expr *>(),
-                           cRParenLoc.unbridged());
+                                               SourceLoc rParenLoc) {
+  return YieldStmt::create(cContext.unbridged(), yieldLoc, lParenLoc,
+                           cYields.unbridged<Expr *>(), rParenLoc);
 }
diff --git a/lib/AST/Bridging/TypeAttributeBridging.cpp b/lib/AST/Bridging/TypeAttributeBridging.cpp
index 8f8e92537ea30..975dacf3ce928 100644
--- a/lib/AST/Bridging/TypeAttributeBridging.cpp
+++ b/lib/AST/Bridging/TypeAttributeBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -33,85 +33,46 @@ using namespace swift;
   }
 #include "swift/AST/TypeAttr.def"
 
-BridgedTypeAttrKind BridgedTypeAttrKind_fromString(BridgedStringRef cStr) {
+BridgedOptionalTypeAttrKind
+BridgedOptionalTypeAttrKind_fromString(BridgedStringRef cStr) {
   auto optKind = TypeAttribute::getAttrKindFromString(cStr.unbridged());
-  if (!optKind)
-    return BridgedTypeAttrKindNone;
-  switch (*optKind) {
-#define TYPE_ATTR(_, CLASS)                                                    \
-  case TypeAttrKind::CLASS:                                                    \
-    return BridgedTypeAttrKind##CLASS;
-#include "swift/AST/TypeAttr.def"
-  }
-}
-
-static std::optional<TypeAttrKind> unbridged(BridgedTypeAttrKind kind) {
-  switch (kind) {
-#define TYPE_ATTR(_, CLASS)                                                    \
-  case BridgedTypeAttrKind##CLASS:                                             \
-    return TypeAttrKind::CLASS;
-#include "swift/AST/TypeAttr.def"
-  case BridgedTypeAttrKindNone:
-    return std::nullopt;
+  if (!optKind) {
+    return BridgedOptionalTypeAttrKind();
   }
-  llvm_unreachable("unhandled enum value");
+  return *optKind;
 }
 
-BridgedTypeAttribute BridgedTypeAttribute_createSimple(
-    BridgedASTContext cContext, BridgedTypeAttrKind cKind,
-    BridgedSourceLoc cAtLoc, BridgedSourceLoc cNameLoc) {
-  auto optKind = unbridged(cKind);
-  assert(optKind && "creating attribute of invalid kind?");
-  return TypeAttribute::createSimple(cContext.unbridged(), *optKind,
-                                     cAtLoc.unbridged(), cNameLoc.unbridged());
+BridgedTypeAttribute
+BridgedTypeAttribute_createSimple(BridgedASTContext cContext,
+                                  swift::TypeAttrKind kind, SourceLoc atLoc,
+                                  SourceLoc nameLoc) {
+  return TypeAttribute::createSimple(cContext.unbridged(), kind, atLoc,
+                                     nameLoc);
 }
 
 BridgedConventionTypeAttr BridgedConventionTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cKwLoc, BridgedSourceRange cParens, BridgedStringRef cName,
-    BridgedSourceLoc cNameLoc, BridgedDeclNameRef cWitnessMethodProtocol,
-    BridgedStringRef cClangType, BridgedSourceLoc cClangTypeLoc) {
-  return new (cContext.unbridged()) ConventionTypeAttr(
-      cAtLoc.unbridged(), cKwLoc.unbridged(), cParens.unbridged(),
-      {cName.unbridged(), cNameLoc.unbridged()},
-      cWitnessMethodProtocol.unbridged(),
-      {cClangType.unbridged(), cClangTypeLoc.unbridged()});
+    BridgedASTContext cContext, SourceLoc atLoc, SourceLoc kwLoc,
+    SourceRange parens, BridgedStringRef cName, SourceLoc nameLoc,
+    BridgedDeclNameRef cWitnessMethodProtocol, BridgedStringRef cClangType,
+    SourceLoc clangTypeLoc) {
+  return new (cContext.unbridged())
+      ConventionTypeAttr(atLoc, kwLoc, parens, {cName.unbridged(), nameLoc},
+                         cWitnessMethodProtocol.unbridged(),
+                         {cClangType.unbridged(), clangTypeLoc});
 }
 
 BridgedDifferentiableTypeAttr BridgedDifferentiableTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cNameLoc, BridgedSourceRange cParensRange,
-    BridgedDifferentiabilityKind cKind, BridgedSourceLoc cKindLoc) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceLoc nameLoc,
+    SourceRange parensRange, BridgedDifferentiabilityKind cKind,
+    SourceLoc kindLoc) {
   return new (cContext.unbridged()) DifferentiableTypeAttr(
-      cAtLoc.unbridged(), cNameLoc.unbridged(), cParensRange.unbridged(),
-      {unbridged(cKind), cKindLoc.unbridged()});
-}
-
-BridgedExecutionTypeAttr BridgedExecutionTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cNameLoc, BridgedSourceRange cParensRange,
-    BridgedExecutionTypeAttrExecutionKind behavior,
-    BridgedSourceLoc cBehaviorLoc) {
-  auto behaviorKind = [=] {
-    switch (behavior) {
-    case BridgedExecutionTypeAttrExecutionKind_Concurrent:
-      return ExecutionKind::Concurrent;
-    case BridgedExecutionTypeAttrExecutionKind_Caller:
-      return ExecutionKind::Caller;
-    }
-    llvm_unreachable("bad kind");
-  }();
-  return new (cContext.unbridged()) ExecutionTypeAttr(
-      cAtLoc.unbridged(), cNameLoc.unbridged(), cParensRange.unbridged(),
-      {behaviorKind, cBehaviorLoc.unbridged()});
+      atLoc, nameLoc, parensRange, {unbridged(cKind), kindLoc});
 }
 
 BridgedIsolatedTypeAttr BridgedIsolatedTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cNameLoc, BridgedSourceRange cParensRange,
-
-    BridgedIsolatedTypeAttrIsolationKind cIsolation,
-    BridgedSourceLoc cIsolationLoc) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceLoc nameLoc,
+    SourceRange parensRange, BridgedIsolatedTypeAttrIsolationKind cIsolation,
+    SourceLoc isolationLoc) {
   auto isolationKind = [=] {
     switch (cIsolation) {
     case BridgedIsolatedTypeAttrIsolationKind_DynamicIsolation:
@@ -120,18 +81,15 @@ BridgedIsolatedTypeAttr BridgedIsolatedTypeAttr_createParsed(
     llvm_unreachable("bad kind");
   }();
   return new (cContext.unbridged()) IsolatedTypeAttr(
-      cAtLoc.unbridged(), cNameLoc.unbridged(), cParensRange.unbridged(),
-      {isolationKind, cIsolationLoc.unbridged()});
+      atLoc, nameLoc, parensRange, {isolationKind, isolationLoc});
 }
 
 BridgedOpaqueReturnTypeOfTypeAttr
 BridgedOpaqueReturnTypeOfTypeAttr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceLoc cKwLoc, BridgedSourceRange cParens,
-    BridgedStringRef cMangled, BridgedSourceLoc cMangledLoc, size_t index,
-    BridgedSourceLoc cIndexLoc) {
+    BridgedASTContext cContext, SourceLoc atLoc, SourceLoc kwLoc,
+    SourceRange parens, BridgedStringRef cMangled, SourceLoc mangledLoc,
+    size_t index, SourceLoc indexLoc) {
   return new (cContext.unbridged()) OpaqueReturnTypeOfTypeAttr(
-      cAtLoc.unbridged(), cKwLoc.unbridged(), cParens.unbridged(),
-      {cMangled.unbridged(), cMangledLoc.unbridged()},
-      {static_cast<unsigned int>(index), cIndexLoc.unbridged()});
+      atLoc, kwLoc, parens, {cMangled.unbridged(), mangledLoc},
+      {static_cast<unsigned int>(index), indexLoc});
 }
diff --git a/lib/AST/Bridging/TypeReprBridging.cpp b/lib/AST/Bridging/TypeReprBridging.cpp
index e87a215fa363f..24e61b351872d 100644
--- a/lib/AST/Bridging/TypeReprBridging.cpp
+++ b/lib/AST/Bridging/TypeReprBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -33,96 +33,83 @@ using namespace swift;
 #define ABSTRACT_TYPEREPR(Id, Parent) TYPEREPR(Id, Parent)
 #include "swift/AST/TypeReprNodes.def"
 
-BridgedUnqualifiedIdentTypeRepr BridgedUnqualifiedIdentTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLoc, BridgedIdentifier id) {
+BridgedUnqualifiedIdentTypeRepr
+BridgedUnqualifiedIdentTypeRepr_createParsed(BridgedASTContext cContext,
+                                             SourceLoc loc, Identifier id) {
   return UnqualifiedIdentTypeRepr::create(cContext.unbridged(),
-                                          DeclNameLoc(cLoc.unbridged()),
-                                          DeclNameRef(id.unbridged()));
+                                          DeclNameLoc(loc), DeclNameRef(id));
 }
 
 BridgedUnqualifiedIdentTypeRepr BridgedUnqualifiedIdentTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedIdentifier name,
-    BridgedSourceLoc cNameLoc, BridgedArrayRef genericArgs,
-    BridgedSourceLoc cLAngleLoc, BridgedSourceLoc cRAngleLoc) {
+    BridgedASTContext cContext, Identifier name, SourceLoc nameLoc,
+    BridgedArrayRef genericArgs, SourceLoc lAngleLoc, SourceLoc rAngleLoc) {
   ASTContext &context = cContext.unbridged();
-  auto Loc = DeclNameLoc(cNameLoc.unbridged());
-  auto Name = DeclNameRef(name.unbridged());
-  SourceLoc lAngleLoc = cLAngleLoc.unbridged();
-  SourceLoc rAngleLoc = cRAngleLoc.unbridged();
+  auto Loc = DeclNameLoc(nameLoc);
+  auto Name = DeclNameRef(name);
   return UnqualifiedIdentTypeRepr::create(context, Loc, Name,
                                           genericArgs.unbridged<TypeRepr *>(),
                                           SourceRange{lAngleLoc, rAngleLoc});
 }
 
-BridgedOptionalTypeRepr
-BridgedOptionalTypeRepr_createParsed(BridgedASTContext cContext,
-                                     BridgedTypeRepr base,
-                                     BridgedSourceLoc cQuestionLoc) {
+BridgedOptionalTypeRepr BridgedOptionalTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr base, SourceLoc questionLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      OptionalTypeRepr(base.unbridged(), cQuestionLoc.unbridged());
+  return new (context) OptionalTypeRepr(base.unbridged(), questionLoc);
 }
 
 BridgedImplicitlyUnwrappedOptionalTypeRepr
 BridgedImplicitlyUnwrappedOptionalTypeRepr_createParsed(
     BridgedASTContext cContext, BridgedTypeRepr base,
-    BridgedSourceLoc cExclamationLoc) {
+    SourceLoc exclamationLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context) ImplicitlyUnwrappedOptionalTypeRepr(
-      base.unbridged(), cExclamationLoc.unbridged());
+  return new (context)
+      ImplicitlyUnwrappedOptionalTypeRepr(base.unbridged(), exclamationLoc);
 }
 
-BridgedArrayTypeRepr BridgedArrayTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedTypeRepr base,
-    BridgedSourceLoc cLSquareLoc, BridgedSourceLoc cRSquareLoc) {
+BridgedArrayTypeRepr
+BridgedArrayTypeRepr_createParsed(BridgedASTContext cContext,
+                                  BridgedTypeRepr base, SourceLoc lSquareLoc,
+                                  SourceLoc rSquareLoc) {
   ASTContext &context = cContext.unbridged();
-  SourceLoc lSquareLoc = cLSquareLoc.unbridged();
-  SourceLoc rSquareLoc = cRSquareLoc.unbridged();
   return new (context)
       ArrayTypeRepr(base.unbridged(), SourceRange{lSquareLoc, rSquareLoc});
 }
 
 BridgedDictionaryTypeRepr BridgedDictionaryTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedSourceLoc cLSquareLoc,
-    BridgedTypeRepr keyType, BridgedSourceLoc cColonloc,
-    BridgedTypeRepr valueType, BridgedSourceLoc cRSquareLoc) {
+    BridgedASTContext cContext, SourceLoc lSquareLoc, BridgedTypeRepr keyType,
+    SourceLoc colonLoc, BridgedTypeRepr valueType, SourceLoc rSquareLoc) {
   ASTContext &context = cContext.unbridged();
-  SourceLoc lSquareLoc = cLSquareLoc.unbridged();
-  SourceLoc colonLoc = cColonloc.unbridged();
-  SourceLoc rSquareLoc = cRSquareLoc.unbridged();
   return new (context)
       DictionaryTypeRepr(keyType.unbridged(), valueType.unbridged(), colonLoc,
                          SourceRange{lSquareLoc, rSquareLoc});
 }
 
 BridgedErrorTypeRepr BridgedErrorTypeRepr_create(BridgedASTContext cContext,
-                                                 BridgedSourceRange cRange) {
-  return ErrorTypeRepr::create(cContext.unbridged(), cRange.unbridged());
+                                                 SourceRange range) {
+  return ErrorTypeRepr::create(cContext.unbridged(), range);
 }
 
 BridgedInlineArrayTypeRepr BridgedInlineArrayTypeRepr_createParsed(
     BridgedASTContext cContext, BridgedTypeRepr cCountType,
-    BridgedTypeRepr cElementType, BridgedSourceRange cBracketsRange) {
-  return InlineArrayTypeRepr::create(
-      cContext.unbridged(), cCountType.unbridged(), cElementType.unbridged(),
-      cBracketsRange.unbridged());
+    BridgedTypeRepr cElementType, SourceRange bracketsRange) {
+  return InlineArrayTypeRepr::create(cContext.unbridged(),
+                                     cCountType.unbridged(),
+                                     cElementType.unbridged(), bracketsRange);
 }
 
 BridgedInverseTypeRepr
 BridgedInverseTypeRepr_createParsed(BridgedASTContext cContext,
-                                    BridgedSourceLoc cTildeLoc,
+                                    SourceLoc tildeLoc,
                                     BridgedTypeRepr cConstraint) {
 
   return new (cContext.unbridged())
-      InverseTypeRepr(cTildeLoc.unbridged(), cConstraint.unbridged());
+      InverseTypeRepr(tildeLoc, cConstraint.unbridged());
 }
 
-BridgedIsolatedTypeRepr
-BridgedIsolatedTypeRepr_createParsed(BridgedASTContext cContext,
-                                     BridgedTypeRepr base,
-                                     BridgedSourceLoc cSpecifierLoc) {
+BridgedIsolatedTypeRepr BridgedIsolatedTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr base, SourceLoc specifierLoc) {
   return new (cContext.unbridged())
-      IsolatedTypeRepr(base.unbridged(), cSpecifierLoc.unbridged());
+      IsolatedTypeRepr(base.unbridged(), specifierLoc);
 }
 
 BridgedLifetimeDependentTypeRepr
@@ -133,53 +120,42 @@ BridgedLifetimeDependentTypeRepr_createParsed(BridgedASTContext cContext,
       LifetimeDependentTypeRepr(base.unbridged(), cEntry.unbridged());
 }
 
-BridgedMetatypeTypeRepr
-BridgedMetatypeTypeRepr_createParsed(BridgedASTContext cContext,
-                                     BridgedTypeRepr baseType,
-                                     BridgedSourceLoc cTypeLoc) {
+BridgedMetatypeTypeRepr BridgedMetatypeTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr baseType, SourceLoc typeLoc) {
   ASTContext &context = cContext.unbridged();
-  SourceLoc tyLoc = cTypeLoc.unbridged();
+  SourceLoc tyLoc = typeLoc;
   return new (context) MetatypeTypeRepr(baseType.unbridged(), tyLoc);
 }
 
 BridgedOwnershipTypeRepr BridgedOwnershipTypeRepr_createParsed(
     BridgedASTContext cContext, BridgedTypeRepr base,
-    BridgedParamSpecifier cSpecifier, BridgedSourceLoc cSpecifierLoc) {
-  return new (cContext.unbridged()) OwnershipTypeRepr(
-      base.unbridged(), unbridge(cSpecifier), cSpecifierLoc.unbridged());
+    BridgedParamSpecifier cSpecifier, SourceLoc specifierLoc) {
+  return new (cContext.unbridged())
+      OwnershipTypeRepr(base.unbridged(), unbridge(cSpecifier), specifierLoc);
 }
 
 BridgedPlaceholderTypeRepr
 BridgedPlaceholderTypeRepr_createParsed(BridgedASTContext cContext,
-                                        BridgedSourceLoc cLoc) {
-  return new (cContext.unbridged()) PlaceholderTypeRepr(cLoc.unbridged());
+                                        SourceLoc loc) {
+  return new (cContext.unbridged()) PlaceholderTypeRepr(loc);
 }
 
-BridgedProtocolTypeRepr
-BridgedProtocolTypeRepr_createParsed(BridgedASTContext cContext,
-                                     BridgedTypeRepr baseType,
-                                     BridgedSourceLoc cProtoLoc) {
+BridgedProtocolTypeRepr BridgedProtocolTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr baseType, SourceLoc protoLoc) {
   ASTContext &context = cContext.unbridged();
-  SourceLoc protoLoc = cProtoLoc.unbridged();
   return new (context) ProtocolTypeRepr(baseType.unbridged(), protoLoc);
 }
 
-BridgedPackElementTypeRepr
-BridgedPackElementTypeRepr_createParsed(BridgedASTContext cContext,
-                                        BridgedTypeRepr base,
-                                        BridgedSourceLoc cEachLoc) {
+BridgedPackElementTypeRepr BridgedPackElementTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr base, SourceLoc eachLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      PackElementTypeRepr(cEachLoc.unbridged(), base.unbridged());
+  return new (context) PackElementTypeRepr(eachLoc, base.unbridged());
 }
 
-BridgedPackExpansionTypeRepr
-BridgedPackExpansionTypeRepr_createParsed(BridgedASTContext cContext,
-                                          BridgedTypeRepr base,
-                                          BridgedSourceLoc cRepeatLoc) {
+BridgedPackExpansionTypeRepr BridgedPackExpansionTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr base, SourceLoc repeatLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      PackExpansionTypeRepr(cRepeatLoc.unbridged(), base.unbridged());
+  return new (context) PackExpansionTypeRepr(repeatLoc, base.unbridged());
 }
 
 BridgedAttributedTypeRepr
@@ -203,78 +179,72 @@ BridgedAttributedTypeRepr_createParsed(BridgedASTContext cContext,
                                     base.unbridged());
 }
 
-BridgedSendingTypeRepr
-BridgedSendingTypeRepr_createParsed(BridgedASTContext cContext,
-                                    BridgedTypeRepr base,
-                                    BridgedSourceLoc cSpecifierLoc) {
+BridgedSendingTypeRepr BridgedSendingTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr base, SourceLoc specifierLoc) {
   return new (cContext.unbridged())
-      SendingTypeRepr(base.unbridged(), cSpecifierLoc.unbridged());
+      SendingTypeRepr(base.unbridged(), specifierLoc);
 }
 
-BridgedVarargTypeRepr
-BridgedVarargTypeRepr_createParsed(BridgedASTContext cContext,
-                                   BridgedTypeRepr base,
-                                   BridgedSourceLoc cEllipsisLoc) {
+BridgedCallerIsolatedTypeRepr BridgedCallerIsolatedTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr base, SourceLoc specifierLoc) {
+  return new (cContext.unbridged())
+      CallerIsolatedTypeRepr(base.unbridged(), specifierLoc);
+}
+
+BridgedVarargTypeRepr BridgedVarargTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr base, SourceLoc ellipsisLoc) {
   ASTContext &context = cContext.unbridged();
-  SourceLoc ellipsisLoc = cEllipsisLoc.unbridged();
   TypeRepr *baseType = base.unbridged();
   return new (context) VarargTypeRepr(baseType, ellipsisLoc);
 }
 
-BridgedTupleTypeRepr BridgedTupleTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedArrayRef elements,
-    BridgedSourceLoc cLParenLoc, BridgedSourceLoc cRParenLoc) {
+BridgedTupleTypeRepr
+BridgedTupleTypeRepr_createParsed(BridgedASTContext cContext,
+                                  BridgedArrayRef elements, SourceLoc lParenLoc,
+                                  SourceLoc rParenLoc) {
   ASTContext &context = cContext.unbridged();
-  SourceLoc lParen = cLParenLoc.unbridged();
-  SourceLoc rParen = cRParenLoc.unbridged();
 
   SmallVector<TupleTypeReprElement, 8> tupleElements;
   for (auto element : elements.unbridged<BridgedTupleTypeElement>()) {
     TupleTypeReprElement elementRepr;
-    elementRepr.Name = element.Name.unbridged();
-    elementRepr.NameLoc = element.NameLoc.unbridged();
-    elementRepr.SecondName = element.SecondName.unbridged();
-    elementRepr.SecondNameLoc = element.SecondNameLoc.unbridged();
-    elementRepr.UnderscoreLoc = element.UnderscoreLoc.unbridged();
-    elementRepr.ColonLoc = element.ColonLoc.unbridged();
+    elementRepr.Name = element.Name;
+    elementRepr.NameLoc = element.NameLoc;
+    elementRepr.SecondName = element.SecondName;
+    elementRepr.SecondNameLoc = element.SecondNameLoc;
+    elementRepr.UnderscoreLoc = element.UnderscoreLoc;
+    elementRepr.ColonLoc = element.ColonLoc;
     elementRepr.Type = element.Type.unbridged();
-    elementRepr.TrailingCommaLoc = element.TrailingCommaLoc.unbridged();
+    elementRepr.TrailingCommaLoc = element.TrailingCommaLoc;
     tupleElements.emplace_back(elementRepr);
   }
 
   return TupleTypeRepr::create(context, tupleElements,
-                               SourceRange{lParen, rParen});
+                               SourceRange{lParenLoc, rParenLoc});
 }
 
 BridgedDeclRefTypeRepr BridgedDeclRefTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedTypeRepr cBase, BridgedIdentifier cName,
-    BridgedSourceLoc cLoc, BridgedArrayRef cGenericArguments,
-    BridgedSourceRange cAngleRange) {
+    BridgedASTContext cContext, BridgedTypeRepr cBase, Identifier name,
+    SourceLoc loc, BridgedArrayRef cGenericArguments, SourceRange angleRange) {
   ASTContext &context = cContext.unbridged();
   auto genericArguments = cGenericArguments.unbridged<TypeRepr *>();
-  auto angleRange = cAngleRange.unbridged();
 
   assert(angleRange.isValid() || genericArguments.empty());
 
-  return DeclRefTypeRepr::create(
-      context, cBase.unbridged(), DeclNameLoc(cLoc.unbridged()),
-      DeclNameRef(cName.unbridged()), genericArguments, angleRange);
+  return DeclRefTypeRepr::create(context, cBase.unbridged(), DeclNameLoc(loc),
+                                 DeclNameRef(name), genericArguments,
+                                 angleRange);
 }
 
 BridgedCompositionTypeRepr
 BridgedCompositionTypeRepr_createEmpty(BridgedASTContext cContext,
-                                       BridgedSourceLoc cAnyLoc) {
+                                       SourceLoc anyLoc) {
   ASTContext &context = cContext.unbridged();
-  SourceLoc anyLoc = cAnyLoc.unbridged();
   return CompositionTypeRepr::createEmptyComposition(context, anyLoc);
 }
 
-BridgedCompositionTypeRepr
-BridgedCompositionTypeRepr_createParsed(BridgedASTContext cContext,
-                                        BridgedArrayRef cTypes,
-                                        BridgedSourceLoc cFirstAmpLoc) {
+BridgedCompositionTypeRepr BridgedCompositionTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedArrayRef cTypes, SourceLoc firstAmpLoc) {
   ASTContext &context = cContext.unbridged();
-  SourceLoc firstAmpLoc = cFirstAmpLoc.unbridged();
   auto types = cTypes.unbridged<TypeRepr *>();
   return CompositionTypeRepr::create(
       context, types, types.front()->getStartLoc(),
@@ -284,21 +254,19 @@ BridgedCompositionTypeRepr_createParsed(BridgedASTContext cContext,
 BridgedCompileTimeLiteralTypeRepr
 BridgedCompileTimeLiteralTypeRepr_createParsed(BridgedASTContext cContext,
                                                BridgedTypeRepr base,
-                                               BridgedSourceLoc cSpecifierLoc) {
+                                               SourceLoc specifierLoc) {
   return new (cContext.unbridged())
-      CompileTimeLiteralTypeRepr(base.unbridged(), cSpecifierLoc.unbridged());
+      CompileTimeLiteralTypeRepr(base.unbridged(), specifierLoc);
 }
 
 BridgedFunctionTypeRepr BridgedFunctionTypeRepr_createParsed(
-    BridgedASTContext cContext, BridgedTypeRepr argsTy,
-    BridgedSourceLoc cAsyncLoc, BridgedSourceLoc cThrowsLoc,
-    BridgedNullableTypeRepr thrownType, BridgedSourceLoc cArrowLoc,
+    BridgedASTContext cContext, BridgedTypeRepr argsTy, SourceLoc asyncLoc,
+    SourceLoc throwsLoc, BridgedNullableTypeRepr thrownType, SourceLoc arrowLoc,
     BridgedTypeRepr resultType) {
   ASTContext &context = cContext.unbridged();
   return new (context) FunctionTypeRepr(
-      nullptr, cast<TupleTypeRepr>(argsTy.unbridged()), cAsyncLoc.unbridged(),
-      cThrowsLoc.unbridged(), thrownType.unbridged(), cArrowLoc.unbridged(),
-      resultType.unbridged());
+      nullptr, cast<TupleTypeRepr>(argsTy.unbridged()), asyncLoc, throwsLoc,
+      thrownType.unbridged(), arrowLoc, resultType.unbridged());
 }
 
 BridgedNamedOpaqueReturnTypeRepr BridgedNamedOpaqueReturnTypeRepr_createParsed(
@@ -309,30 +277,22 @@ BridgedNamedOpaqueReturnTypeRepr BridgedNamedOpaqueReturnTypeRepr_createParsed(
       NamedOpaqueReturnTypeRepr(baseTy.unbridged(), genericParams.unbridged());
 }
 
-BridgedOpaqueReturnTypeRepr
-BridgedOpaqueReturnTypeRepr_createParsed(BridgedASTContext cContext,
-                                         BridgedSourceLoc cOpaqueLoc,
-                                         BridgedTypeRepr baseTy) {
+BridgedOpaqueReturnTypeRepr BridgedOpaqueReturnTypeRepr_createParsed(
+    BridgedASTContext cContext, SourceLoc opaqueLoc, BridgedTypeRepr baseTy) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      OpaqueReturnTypeRepr(cOpaqueLoc.unbridged(), baseTy.unbridged());
+  return new (context) OpaqueReturnTypeRepr(opaqueLoc, baseTy.unbridged());
 }
 
-BridgedExistentialTypeRepr
-BridgedExistentialTypeRepr_createParsed(BridgedASTContext cContext,
-                                        BridgedSourceLoc cAnyLoc,
-                                        BridgedTypeRepr baseTy) {
+BridgedExistentialTypeRepr BridgedExistentialTypeRepr_createParsed(
+    BridgedASTContext cContext, SourceLoc anyLoc, BridgedTypeRepr baseTy) {
   ASTContext &context = cContext.unbridged();
-  return new (context)
-      ExistentialTypeRepr(cAnyLoc.unbridged(), baseTy.unbridged());
+  return new (context) ExistentialTypeRepr(anyLoc, baseTy.unbridged());
 }
 
 BridgedIntegerTypeRepr
 BridgedIntegerTypeRepr_createParsed(BridgedASTContext cContext,
-                                    BridgedStringRef cString,
-                                    BridgedSourceLoc cLoc,
-                                    BridgedSourceLoc cMinusLoc) {
+                                    BridgedStringRef cString, SourceLoc loc,
+                                    SourceLoc minusLoc) {
   ASTContext &context = cContext.unbridged();
-  return new (context) IntegerTypeRepr(cString.unbridged(), cLoc.unbridged(),
-                                       cMinusLoc.unbridged());
+  return new (context) IntegerTypeRepr(cString.unbridged(), loc, minusLoc);
 }
diff --git a/lib/AST/Builtins.cpp b/lib/AST/Builtins.cpp
index 3b6c17bebbc76..3ed613359e9e5 100644
--- a/lib/AST/Builtins.cpp
+++ b/lib/AST/Builtins.cpp
@@ -49,23 +49,61 @@ bool BuiltinInfo::isReadNone() const {
   return strchr(BuiltinExtraInfo[(unsigned)ID].Attributes, 'n') != nullptr;
 }
 
-const llvm::AttributeList &
-IntrinsicInfo::getOrCreateAttributes(ASTContext &Ctx) const {
-  using DenseMapInfo = llvm::DenseMapInfo<llvm::AttributeList>;
-  if (DenseMapInfo::isEqual(Attrs, DenseMapInfo::getEmptyKey())) {
-    Attrs = llvm::Intrinsic::getAttributes(Ctx.getIntrinsicScratchContext(), ID);
+const llvm::AttributeSet &
+IntrinsicInfo::getOrCreateFnAttributes(ASTContext &Ctx) const {
+  using DenseMapInfo = llvm::DenseMapInfo<llvm::AttributeSet>;
+  if (DenseMapInfo::isEqual(FnAttrs, DenseMapInfo::getEmptyKey())) {
+    FnAttrs =
+        llvm::Intrinsic::getFnAttributes(Ctx.getIntrinsicScratchContext(), ID);
   }
-  return Attrs;
+  return FnAttrs;
 }
 
 Type swift::getBuiltinType(ASTContext &Context, StringRef Name) {
-  if (Name == "FixedArray") {
-    return BuiltinUnboundGenericType::get(TypeKind::BuiltinFixedArray, Context);
+  // We first map to a kind using a StringSwitch so that we can perform an
+  // exhaustive switch making it easier to know to update this code.
+  auto kind =
+      llvm::StringSwitch<std::optional<BuiltinTypeKind>>(Name)
+          .Case("FixedArray", BuiltinTypeKind::BuiltinFixedArray)
+          .StartsWith("Vec", BuiltinTypeKind::BuiltinVector)
+          .Case("RawPointer", BuiltinTypeKind::BuiltinRawPointer)
+          .Case("RawUnsafeContinuation",
+                BuiltinTypeKind::BuiltinRawUnsafeContinuation)
+          .Case("Job", BuiltinTypeKind::BuiltinJob)
+          .Case("DefaultActorStorage",
+                BuiltinTypeKind::BuiltinDefaultActorStorage)
+          .Case("NonDefaultDistributedActorStorage",
+                BuiltinTypeKind::BuiltinNonDefaultDistributedActorStorage)
+          .Case("Executor", BuiltinTypeKind::BuiltinExecutor)
+          .Case("NativeObject", BuiltinTypeKind::BuiltinNativeObject)
+          .Case("BridgeObject", BuiltinTypeKind::BuiltinBridgeObject)
+          .Case("UnsafeValueBuffer", BuiltinTypeKind::BuiltinUnsafeValueBuffer)
+          .Case("PackIndex", BuiltinTypeKind::BuiltinPackIndex)
+          .StartsWith("FP", BuiltinTypeKind::BuiltinFloat)
+          .Case("Word", BuiltinTypeKind::BuiltinInteger)
+          .Case("IntLiteral", BuiltinTypeKind::BuiltinIntegerLiteral)
+          .StartsWith("Int", BuiltinTypeKind::BuiltinInteger)
+          .Default({});
+
+  // Handle types that are not BuiltinTypeKinds.
+  if (!kind) {
+    if (Name == "SILToken")
+      return Context.TheSILTokenType;
+
+    // AnyObject is the empty class-constrained existential.
+    if (Name == "AnyObject")
+      return CanType(ProtocolCompositionType::theAnyObjectType(Context));
+
+    return Type();
   }
 
-  // Vectors are VecNxT, where "N" is the number of elements and
-  // T is the element type.
-  if (Name.starts_with("Vec")) {
+  switch (*kind) {
+  case BuiltinTypeKind::BuiltinFixedArray:
+    return BuiltinUnboundGenericType::get(TypeKind::BuiltinFixedArray, Context);
+
+  case BuiltinTypeKind::BuiltinVector: {
+    // Vectors are VecNxT, where "N" is the number of elements and
+    // T is the element type.
     Name = Name.substr(3);
     StringRef::size_type xPos = Name.find('x');
     if (xPos == StringRef::npos)
@@ -82,67 +120,62 @@ Type swift::getBuiltinType(ASTContext &Context, StringRef Name) {
 
     return BuiltinVectorType::get(Context, elementType, numElements);
   }
-
-  if (Name == "RawPointer")
+  case BuiltinTypeKind::BuiltinRawPointer:
     return Context.TheRawPointerType;
-  if (Name == "RawUnsafeContinuation")
+  case BuiltinTypeKind::BuiltinRawUnsafeContinuation:
     return Context.TheRawUnsafeContinuationType;
-  if (Name == "Job")
+  case BuiltinTypeKind::BuiltinJob:
     return Context.TheJobType;
-  if (Name == "DefaultActorStorage")
+  case BuiltinTypeKind::BuiltinDefaultActorStorage:
     return Context.TheDefaultActorStorageType;
-  if (Name == "NonDefaultDistributedActorStorage")
+  case BuiltinTypeKind::BuiltinNonDefaultDistributedActorStorage:
     return Context.TheNonDefaultDistributedActorStorageType;
-  if (Name == "Executor")
+  case BuiltinTypeKind::BuiltinExecutor:
     return Context.TheExecutorType;
-  if (Name == "NativeObject")
+  case BuiltinTypeKind::BuiltinNativeObject:
     return Context.TheNativeObjectType;
-  if (Name == "BridgeObject")
+  case BuiltinTypeKind::BuiltinBridgeObject:
     return Context.TheBridgeObjectType;
-  if (Name == "SILToken")
-    return Context.TheSILTokenType;
-  if (Name == "UnsafeValueBuffer")
+  case BuiltinTypeKind::BuiltinUnsafeValueBuffer:
     return Context.TheUnsafeValueBufferType;
-  if (Name == "PackIndex")
+  case BuiltinTypeKind::BuiltinPackIndex:
     return Context.ThePackIndexType;
-  
-  if (Name == "FPIEEE32")
-    return Context.TheIEEE32Type;
-  if (Name == "FPIEEE64")
-    return Context.TheIEEE64Type;
+  case BuiltinTypeKind::BuiltinFloat:
+    // Target specific FP types.
+    if (Name == "FPIEEE32")
+      return Context.TheIEEE32Type;
+    if (Name == "FPIEEE64")
+      return Context.TheIEEE64Type;
+    if (Name == "FPIEEE16")
+      return Context.TheIEEE16Type;
+    if (Name == "FPIEEE80")
+      return Context.TheIEEE80Type;
+    if (Name == "FPIEEE128")
+      return Context.TheIEEE128Type;
+    if (Name == "FPPPC128")
+      return Context.ThePPC128Type;
+    return Type();
+  case BuiltinTypeKind::BuiltinInteger:
+    if (Name == "Word")
+      return BuiltinIntegerType::getWordType(Context);
 
-  if (Name == "Word")
-    return BuiltinIntegerType::getWordType(Context);
+    if (Name == "Int") {
+      return BuiltinUnboundGenericType::get(TypeKind::BuiltinInteger, Context);
+    }
 
-  if (Name == "IntLiteral")
+    // Handle 'int8' and friends.
+    if (Name.substr(0, 3) == "Int") {
+      unsigned BitWidth;
+      if (!Name.substr(3).getAsInteger(10, BitWidth) && BitWidth <= 2048 &&
+          BitWidth != 0) // Cap to prevent unsound things.
+        return BuiltinIntegerType::get(BitWidth, Context);
+    }
+    return Type();
+  case BuiltinTypeKind::BuiltinIntegerLiteral:
     return Context.TheIntegerLiteralType;
-
-  if (Name == "Int") {
-    return BuiltinUnboundGenericType::get(TypeKind::BuiltinInteger, Context);
-  }
-  
-  // Handle 'int8' and friends.
-  if (Name.substr(0, 3) == "Int") {
-    unsigned BitWidth;
-    if (!Name.substr(3).getAsInteger(10, BitWidth) &&
-        BitWidth <= 2048 && BitWidth != 0)  // Cap to prevent unsound things.
-      return BuiltinIntegerType::get(BitWidth, Context);
+  case BuiltinTypeKind::BuiltinUnboundGeneric:
+    return Type();
   }
-  
-  // Target specific FP types.
-  if (Name == "FPIEEE16")
-    return Context.TheIEEE16Type;
-  if (Name == "FPIEEE80")
-    return Context.TheIEEE80Type;
-  if (Name == "FPIEEE128")
-    return Context.TheIEEE128Type;
-  if (Name == "FPPPC128")
-    return Context.ThePPC128Type;
-
-  // AnyObject is the empty class-constrained existential.
-  if (Name == "AnyObject")
-    return CanType(
-      ProtocolCompositionType::theAnyObjectType(Context));
 
   return Type();
 }
@@ -890,16 +923,14 @@ static ValueDecl *getRefCountingOperation(ASTContext &ctx, Identifier id) {
 static ValueDecl *getLoadOperation(ASTContext &ctx, Identifier id) {
   return getBuiltinFunction(ctx, id, _thin,
                             _generics(_unrestricted,
-                                      _conformsTo(_typeparam(0), _copyable),
-                                      _conformsTo(_typeparam(0), _escapable)),
+                                      _conformsTo(_typeparam(0), _copyable)),
                             _parameters(_rawPointer),
                             _typeparam(0));
 }
 
 static ValueDecl *getTakeOperation(ASTContext &ctx, Identifier id) {
   return getBuiltinFunction(ctx, id, _thin,
-                            _generics(_unrestricted,
-                                      _conformsTo(_typeparam(0), _escapable)),
+                            _generics(_unrestricted),
                             _parameters(_rawPointer),
                             _typeparam(0));
 }
@@ -1994,6 +2025,26 @@ static ValueDecl *getInsertElementOperation(ASTContext &Context, Identifier Id,
   return getBuiltinFunction(Id, ArgElts, VecTy);
 }
 
+static ValueDecl *getSelectOperation(ASTContext &Context, Identifier Id,
+                                     Type PredTy, Type ValueTy) {
+  // Check for (NxInt1, NxTy, NxTy) -> NxTy
+  auto VecPredTy = PredTy->getAs<BuiltinVectorType>();
+  if (VecPredTy) {
+    // ValueTy must also be vector type with matching element count.
+    auto VecValueTy = ValueTy->getAs<BuiltinVectorType>();
+    if (!VecValueTy ||
+        VecPredTy->getNumElements() != VecValueTy->getNumElements())
+      return nullptr;
+  } else {
+    // Type is (Int1, Ty, Ty) -> Ty
+    auto IntTy = PredTy->getAs<BuiltinIntegerType>();
+    if (!IntTy || !IntTy->isFixedWidth() || IntTy->getFixedWidth() != 1)
+      return nullptr;
+  }
+  Type ArgElts[] = { PredTy, ValueTy, ValueTy };
+  return getBuiltinFunction(Id, ArgElts, ValueTy);
+}
+
 static ValueDecl *getShuffleVectorOperation(ASTContext &Context, Identifier Id,
                                  Type FirstTy, Type SecondTy) {
   // (Vector<N, T>, Vector<N, T>, Vector<M, Int32) -> Vector<M, T>
@@ -2015,6 +2066,38 @@ static ValueDecl *getShuffleVectorOperation(ASTContext &Context, Identifier Id,
   return getBuiltinFunction(Id, ArgElts, ResultTy);
 }
 
+static ValueDecl *getInterleaveOperation(ASTContext &Context, Identifier Id,
+                                         Type FirstTy) {
+  // (Vector<N,T>, Vector<N,T>) -> (Vector<N,T>, Vector<N,T>)
+  auto VecTy = FirstTy->getAs<BuiltinVectorType>();
+  // Require even length because we don't need anything else to support Swift's
+  // SIMD types and it saves us from having to define what happens for odd
+  // lengths until we actually need to care about them.
+  if (!VecTy || VecTy->getNumElements() % 2 != 0)
+    return nullptr;
+  
+  Type ArgElts[] = { VecTy, VecTy };
+  TupleTypeElt ResultElts[] = { FirstTy, FirstTy };
+  Type ResultTy = TupleType::get(ResultElts, Context);
+  return getBuiltinFunction(Id, ArgElts, ResultTy);
+}
+
+static ValueDecl *getDeinterleaveOperation(ASTContext &Context, Identifier Id,
+                                           Type FirstTy) {
+  // (Vector<N,T>, Vector<N,T>) -> (Vector<N,T>, Vector<N,T>)
+  auto VecTy = FirstTy->getAs<BuiltinVectorType>();
+  // Require even length because we don't need anything else to support Swift's
+  // SIMD types and it saves us from having to define what happens for odd
+  // lengths until we actually need to care about them.
+  if (!VecTy || VecTy->getNumElements() % 2 != 0)
+    return nullptr;
+  
+  Type ArgElts[] = { VecTy, VecTy };
+  TupleTypeElt ResultElts[] = { FirstTy, FirstTy };
+  Type ResultTy = TupleType::get(ResultElts, Context);
+  return getBuiltinFunction(Id, ArgElts, ResultTy);
+}
+
 static ValueDecl *getStaticReportOperation(ASTContext &Context, Identifier Id) {
   auto BoolTy = BuiltinIntegerType::get(1, Context);
   auto MessageTy = Context.TheRawPointerType;
@@ -2343,18 +2426,6 @@ bool swift::canBuiltinBeOverloadedForType(BuiltinValueKind ID, Type Ty) {
   return isBuiltinTypeOverloaded(Ty, OverloadedBuiltinKinds[unsigned(ID)]);
 }
 
-/// Table of string intrinsic names indexed by enum value.
-static const char *const IntrinsicNameTable[] = {
-    "not_intrinsic",
-#define GET_INTRINSIC_NAME_TABLE
-#include "llvm/IR/IntrinsicImpl.inc"
-#undef GET_INTRINSIC_NAME_TABLE
-};
-
-#define GET_INTRINSIC_TARGET_DATA
-#include "llvm/IR/IntrinsicImpl.inc"
-#undef GET_INTRINSIC_TARGET_DATA
-
 llvm::Intrinsic::ID swift::getLLVMIntrinsicID(StringRef InName) {
   using namespace llvm;
 
@@ -2370,10 +2441,8 @@ llvm::Intrinsic::ID swift::getLLVMIntrinsicID(StringRef InName) {
     NameS.push_back(C == '_' ? '.' : C);
 
   const char *Name = NameS.c_str();
-  ArrayRef<const char *> NameTable(&IntrinsicNameTable[1],
-                                   TargetInfos[1].Offset);
-  int Idx = Intrinsic::lookupLLVMIntrinsicByName(NameTable, Name);
-  return static_cast<Intrinsic::ID>(Idx + 1);
+
+  return Intrinsic::lookupIntrinsicID(Name);
 }
 
 llvm::Intrinsic::ID
@@ -2459,7 +2528,6 @@ Type IntrinsicTypeDecoder::decodeImmediate() {
   case IITDescriptor::Metadata:
   case IITDescriptor::ExtendArgument:
   case IITDescriptor::TruncArgument:
-  case IITDescriptor::HalfVecArgument:
   case IITDescriptor::VarArg:
   case IITDescriptor::Token:
   case IITDescriptor::VecOfAnyPtrsToElt:
@@ -2468,6 +2536,7 @@ Type IntrinsicTypeDecoder::decodeImmediate() {
   case IITDescriptor::Subdivide4Argument:
   case IITDescriptor::PPCQuad:
   case IITDescriptor::AArch64Svcount:
+  case IITDescriptor::OneNthEltsVecArgument:
     // These types cannot be expressed in swift yet.
     return Type();
 
@@ -2565,8 +2634,8 @@ getSwiftFunctionTypeForIntrinsic(llvm::Intrinsic::ID ID,
   // Translate LLVM function attributes to Swift function attributes.
   IntrinsicInfo II;
   II.ID = ID;
-  auto attrs = II.getOrCreateAttributes(Context);
-  if (attrs.hasFnAttr(llvm::Attribute::NoReturn)) {
+  auto &attrs = II.getOrCreateFnAttributes(Context);
+  if (attrs.hasAttribute(llvm::Attribute::NoReturn)) {
     ResultTy = Context.getNeverType();
     if (!ResultTy)
       return false;
@@ -3112,6 +3181,7 @@ ValueDecl *swift::getBuiltinValueDecl(ASTContext &Context, Identifier Id) {
     return getUnreachableOperation(Context, Id);
       
   case BuiltinValueKind::ZeroInitializer:
+  case BuiltinValueKind::PrepareInitialization:
     return getZeroInitializerOperation(Context, Id);
       
   case BuiltinValueKind::Once:
@@ -3132,10 +3202,22 @@ ValueDecl *swift::getBuiltinValueDecl(ASTContext &Context, Identifier Id) {
   case BuiltinValueKind::InsertElement:
     if (Types.size() != 3) return nullptr;
     return getInsertElementOperation(Context, Id, Types[0], Types[1], Types[2]);
+    
+  case BuiltinValueKind::Select:
+    if (Types.size() != 2) return nullptr;
+    return getSelectOperation(Context, Id, Types[0], Types[1]);
       
   case BuiltinValueKind::ShuffleVector:
     if (Types.size() != 2) return nullptr;
     return getShuffleVectorOperation(Context, Id, Types[0], Types[1]);
+    
+  case BuiltinValueKind::Interleave:
+    if (Types.size() != 1) return nullptr;
+    return getInterleaveOperation(Context, Id, Types[0]);
+    
+  case BuiltinValueKind::Deinterleave:
+    if (Types.size() != 1) return nullptr;
+    return getDeinterleaveOperation(Context, Id, Types[0]);
 
   case BuiltinValueKind::StaticReport:
     if (!Types.empty()) return nullptr;
@@ -3528,16 +3610,9 @@ StringRef BuiltinType::getTypeName(SmallVectorImpl<char> &result,
     }
     break;
   }
-  case BuiltinTypeKind::BuiltinFixedArray: {
-    auto bfa = cast<BuiltinFixedArrayType>(this);
-    printer << MAYBE_GET_NAMESPACED_BUILTIN(BUILTIN_TYPE_NAME_FIXEDARRAY)
-            << '<';
-    bfa->getSize()->print(printer);
-    printer << ", ";
-    bfa->getElementType()->print(printer);
-    printer << '>';
+  case BuiltinTypeKind::BuiltinFixedArray:
+    printer << MAYBE_GET_NAMESPACED_BUILTIN(BUILTIN_TYPE_NAME_FIXEDARRAY);
     break;
-  }
   case BuiltinTypeKind::BuiltinUnboundGeneric: {
     auto bug = cast<BuiltinUnboundGenericType>(this);
     printer << MAYBE_GET_NAMESPACED_BUILTIN(bug->getBuiltinTypeName());
diff --git a/lib/AST/CMakeLists.txt b/lib/AST/CMakeLists.txt
index d2c7fab6572ce..17b748e1ee468 100644
--- a/lib/AST/CMakeLists.txt
+++ b/lib/AST/CMakeLists.txt
@@ -30,6 +30,7 @@ add_swift_host_library(swiftAST STATIC
   AvailabilityConstraint.cpp
   AvailabilityContext.cpp
   AvailabilityDomain.cpp
+  AvailabilityQuery.cpp
   AvailabilityScope.cpp
   AvailabilityScopeBuilder.cpp
   AvailabilitySpec.cpp
@@ -44,7 +45,9 @@ add_swift_host_library(swiftAST STATIC
   Decl.cpp
   DeclContext.cpp
   DeclContextDumper.cpp
+  DeclNameExtractor.cpp
   DeclNameLoc.cpp
+  DiagnosticArgument.cpp
   DiagnosticBridge.cpp
   DiagnosticConsumer.cpp
   DiagnosticEngine.cpp
@@ -85,7 +88,7 @@ add_swift_host_library(swiftAST STATIC
   ParameterPack.cpp
   Parameter.cpp
   Pattern.cpp
-  PlatformKind.cpp
+  PlatformKindUtils.cpp
   PluginLoader.cpp
   PluginRegistry.cpp
   PrettyStackTrace.cpp
@@ -94,6 +97,7 @@ add_swift_host_library(swiftAST STATIC
   RawComment.cpp
   Requirement.cpp
   RequirementEnvironment.cpp
+  RequirementMachine/ApplyInverses.cpp
   RequirementMachine/ConcreteContraction.cpp
   RequirementMachine/ConcreteTypeWitness.cpp
   RequirementMachine/Diagnostics.cpp
@@ -176,7 +180,7 @@ target_link_libraries(swiftAST
 
 if (SWIFT_BUILD_SWIFT_SYNTAX)
   target_link_libraries(swiftAST
-    PRIVATE swiftASTGen)
+    PRIVATE swiftASTGen swiftBasicSwift)
 endif()
 
 set_swift_llvm_is_available(swiftAST)
diff --git a/lib/AST/CaptureInfo.cpp b/lib/AST/CaptureInfo.cpp
index f2b12c76ff843..4a88879a085a9 100644
--- a/lib/AST/CaptureInfo.cpp
+++ b/lib/AST/CaptureInfo.cpp
@@ -77,7 +77,7 @@ CaptureInfo::CaptureInfo(ASTContext &ctx, ArrayRef<CapturedValue> captures,
   // This is the only kind of local generic environment we can capture right now.
 #ifndef NDEBUG
   for (auto *env : genericEnv) {
-    assert(env->getKind() == GenericEnvironment::Kind::OpenedElement);
+    assert(env->getKind() == GenericEnvironment::Kind::Element);
   }
 #endif
 
diff --git a/lib/AST/ClangTypeConverter.cpp b/lib/AST/ClangTypeConverter.cpp
index 1b1848da354b0..464a595942de1 100644
--- a/lib/AST/ClangTypeConverter.cpp
+++ b/lib/AST/ClangTypeConverter.cpp
@@ -40,6 +40,7 @@
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Sema/Sema.h"
 
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/Compiler.h"
 
@@ -70,7 +71,7 @@ getClangBuiltinTypeFromKind(const clang::ASTContext &context,
 #define SVE_TYPE(Name, Id, SingletonId)                                        \
   case clang::BuiltinType::Id:                                                 \
     return context.SingletonId;
-#include "clang/Basic/AArch64SVEACLETypes.def"
+#include "clang/Basic/AArch64ACLETypes.def"
 #define PPC_VECTOR_TYPE(Name, Id, Size)                                        \
   case clang::BuiltinType::Id:                                                 \
     return context.Id##Ty;
@@ -83,10 +84,14 @@ getClangBuiltinTypeFromKind(const clang::ASTContext &context,
   case clang::BuiltinType::Id:                                                 \
     return context.SingletonId;
 #include "clang/Basic/WebAssemblyReferenceTypes.def"
-#define AMDGPU_TYPE(Name, Id, SingletonId)                                     \
+#define AMDGPU_TYPE(Name, Id, SingletonId, Width, Align)                       \
   case clang::BuiltinType::Id:                                                 \
     return context.SingletonId;
 #include "clang/Basic/AMDGPUTypes.def"
+#define HLSL_INTANGIBLE_TYPE(Name, Id, SingletonId)                            \
+  case clang::BuiltinType::Id:                                                 \
+    return context.SingletonId;
+#include "clang/Basic/HLSLIntangibleTypes.def"
   }
 
   // Not a valid BuiltinType.
@@ -122,11 +127,13 @@ const clang::ASTContext &clangCtx) {
 
 } // end anonymous namespace
 
-const clang::Type *ClangTypeConverter::getFunctionType(
-    ArrayRef<AnyFunctionType::Param> params, Type resultTy,
-    AnyFunctionType::Representation repr) {
-
-  auto resultClangTy = convert(resultTy);
+template <bool templateArgument>
+const clang::Type *
+ClangTypeConverter::getFunctionType(ArrayRef<AnyFunctionType::Param> params,
+                                    Type resultTy,
+                                    AnyFunctionType::Representation repr) {
+  auto resultClangTy =
+      templateArgument ? convertTemplateArgument(resultTy) : convert(resultTy);
   if (resultClangTy.isNull())
     return nullptr;
 
@@ -134,7 +141,8 @@ const clang::Type *ClangTypeConverter::getFunctionType(
   SmallVector<clang::QualType, 4> paramsClangTy;
   bool someParamIsConsumed = false;
   for (auto p : params) {
-    auto pc = convert(p.getPlainType());
+    auto pc = templateArgument ? convertTemplateArgument(p.getPlainType())
+                               : convert(p.getPlainType());
     if (pc.isNull())
       return nullptr;
     clang::FunctionProtoType::ExtParameterInfo extParamInfo;
@@ -165,16 +173,21 @@ const clang::Type *ClangTypeConverter::getFunctionType(
   llvm_unreachable("invalid representation");
 }
 
+template <bool templateArgument>
 const clang::Type *
 ClangTypeConverter::getFunctionType(ArrayRef<SILParameterInfo> params,
                                     std::optional<SILResultInfo> result,
                                     SILFunctionType::Representation repr) {
-
-  // Using the interface type is sufficient as type parameters get mapped to
-  // `id`, since ObjC lightweight generics use type erasure. (See also: SE-0057)
-  auto resultClangTy = result.has_value()
-                     ? convert(result.value().getInterfaceType())
-                     : ClangASTContext.VoidTy;
+  clang::QualType resultClangTy = ClangASTContext.VoidTy;
+  if (result) {
+    // Using the interface type is sufficient as type parameters get mapped to
+    // `id`, since ObjC lightweight generics use type erasure.
+    //
+    // (See also: SE-0057)
+    auto interfaceType = result->getInterfaceType();
+    resultClangTy = templateArgument ? convertTemplateArgument(interfaceType)
+                                     : convert(interfaceType);
+  }
 
   if (resultClangTy.isNull())
     return nullptr;
@@ -183,7 +196,8 @@ ClangTypeConverter::getFunctionType(ArrayRef<SILParameterInfo> params,
   SmallVector<clang::QualType, 4> paramsClangTy;
   bool someParamIsConsumed = false;
   for (auto &p : params) {
-    auto pc = convert(p.getInterfaceType());
+    auto pc = templateArgument ? convertTemplateArgument(p.getInterfaceType())
+                               : convert(p.getInterfaceType());
     if (pc.isNull())
       return nullptr;
     clang::FunctionProtoType::ExtParameterInfo extParamInfo;
@@ -565,18 +579,18 @@ ClangTypeConverter::visitBoundGenericType(BoundGenericType *type) {
   }
 
   if (auto kind = classifyPointer(type))
-    return convertPointerType(argType, kind.value(),
-                              /*templateArgument=*/false);
+    return convertPointerType</*templateArgument=*/false>(argType,
+                                                          kind.value());
 
   if (auto width = classifySIMD(type))
-    return convertSIMDType(argType, width.value(), /*templateArgument=*/false);
+    return convertSIMDType</*templateArgument=*/false>(argType, width.value());
 
   return clang::QualType();
 }
 
+template <bool templateArgument>
 clang::QualType ClangTypeConverter::convertSIMDType(CanType scalarType,
-                                                    unsigned width,
-                                                    bool templateArgument) {
+                                                    unsigned width) {
   clang::QualType scalarTy = templateArgument
                                  ? convertTemplateArgument(scalarType)
                                  : convert(scalarType);
@@ -588,9 +602,9 @@ clang::QualType ClangTypeConverter::convertSIMDType(CanType scalarType,
   return vectorTy;
 }
 
+template <bool templateArgument>
 clang::QualType ClangTypeConverter::convertPointerType(CanType pointeeType,
-                                                       PointerKind kind,
-                                                       bool templateArgument) {
+                                                       PointerKind kind) {
   switch (kind) {
   case PointerKind::Unmanaged:
     return templateArgument ? clang::QualType() : convert(pointeeType);
@@ -643,14 +657,16 @@ clang::QualType ClangTypeConverter::visitEnumType(EnumType *type) {
   if (type->isUninhabited())
     return convert(Context.TheEmptyTupleType);
 
-  if (!type->getDecl()->isObjC())
-    // Can't translate something not marked with @objc
+  auto ED = type->getDecl();
+  if (!ED->isCCompatibleEnum())
+    // Can't translate something not marked with @objc or @c.
     return clang::QualType();
 
   // @objc enums lower to their raw types.
-  return convert(type->getDecl()->getRawType());
+  return convert(ED->getRawType());
 }
 
+template <bool templateArgument>
 clang::QualType ClangTypeConverter::visitFunctionType(FunctionType *type) {
   const clang::Type *clangTy = nullptr;
   auto repr = type->getRepresentation();
@@ -665,12 +681,15 @@ clang::QualType ClangTypeConverter::visitFunctionType(FunctionType *type) {
     auto newRepr = (repr == FunctionTypeRepresentation::Swift
                         ? FunctionTypeRepresentation::Block
                         : repr);
-    clangTy = getFunctionType(type->getParams(), type->getResult(), newRepr);
+    clangTy = getFunctionType<templateArgument>(type->getParams(),
+                                                type->getResult(), newRepr);
   }
   return clang::QualType(clangTy, 0);
 }
 
-clang::QualType ClangTypeConverter::visitSILFunctionType(SILFunctionType *type) {
+template <bool templateArgument>
+clang::QualType
+ClangTypeConverter::visitSILFunctionType(SILFunctionType *type) {
   const clang::Type *clangTy = nullptr;
   auto repr = type->getRepresentation();
   bool useClangTypes = type->getASTContext().LangOpts.UseClangFunctionTypes;
@@ -688,7 +707,8 @@ clang::QualType ClangTypeConverter::visitSILFunctionType(SILFunctionType *type)
     auto optionalResult = results.empty()
                               ? std::nullopt
                               : std::optional<SILResultInfo>(results[0]);
-    clangTy = getFunctionType(type->getParameters(), optionalResult, newRepr);
+    clangTy = getFunctionType<templateArgument>(type->getParameters(),
+                                                optionalResult, newRepr);
   }
   return clang::QualType(clangTy, 0);
 }
@@ -798,6 +818,15 @@ ClangTypeConverter::visitBuiltinFloatType(BuiltinFloatType *type) {
   llvm_unreachable("cannot translate floating-point format to C");
 }
 
+clang::QualType
+ClangTypeConverter::visitBuiltinVectorType(BuiltinVectorType *type) {
+  auto &clangCtx = ClangASTContext;
+  auto eltTy = visit(type->getElementType());
+  return clangCtx.getVectorType(
+    eltTy, type->getNumElements(), clang::VectorKind::Generic
+  );
+}
+
 clang::QualType ClangTypeConverter::visitArchetypeType(ArchetypeType *type) {
   // We see these in the case where we invoke an @objc function
   // through a protocol.
@@ -866,8 +895,15 @@ ClangTypeConverter::convertClangDecl(Type type, const clang::Decl *clangDecl) {
 
   if (auto clangTypeDecl = dyn_cast<clang::TypeDecl>(clangDecl)) {
     auto qualType = ctx.getTypeDeclType(clangTypeDecl);
-    if (type->isForeignReferenceType())
+    if (type->isForeignReferenceType()) {
       qualType = ctx.getPointerType(qualType);
+      auto nonNullAttr = new (ctx) clang::TypeNonNullAttr(
+          ctx,
+          clang::AttributeCommonInfo(
+              clang::SourceRange(), clang::AttributeCommonInfo::AT_TypeNonNull,
+              clang::AttributeCommonInfo::Form::Implicit()));
+      qualType = ctx.getAttributedType(nonNullAttr, qualType, qualType);
+    }
 
     return qualType.getUnqualifiedType();
   }
@@ -933,6 +969,13 @@ clang::QualType ClangTypeConverter::convertTemplateArgument(Type type) {
   if (auto floatType = type->getAs<BuiltinFloatType>())
     return withCache([&]() { return visitBuiltinFloatType(floatType); });
 
+  if (auto tupleType = type->getAs<TupleType>()) {
+    // We do not call visitTupleType() because we cannot yet handle tuples with
+    // a non-zero number of elements.
+    if (tupleType->getNumElements() == 0)
+      return ClangASTContext.VoidTy;
+  }
+
   if (auto structType = type->getAs<StructType>()) {
     // Swift structs are not supported in general, but some foreign types are
     // imported as Swift structs. We reverse that mapping here.
@@ -953,8 +996,6 @@ clang::QualType ClangTypeConverter::convertTemplateArgument(Type type) {
     return withCache([&]() { return reverseBuiltinTypeMapping(structType); });
   }
 
-  // TODO: function pointers are not yet supported, but they should be.
-
   if (auto boundGenericType = type->getAs<BoundGenericType>()) {
     if (boundGenericType->getGenericArgs().size() != 1)
       // Must've got something other than a T?, *Pointer<T>, or SIMD*<T>
@@ -968,8 +1009,8 @@ clang::QualType ClangTypeConverter::convertTemplateArgument(Type type) {
           auto pointeeType = argType->getAs<BoundGenericType>()
                                  ->getGenericArgs()[0]
                                  ->getCanonicalType();
-          return convertPointerType(pointeeType, kind.value(),
-                                    /*templateArgument=*/true);
+          return convertPointerType</*templateArgument=*/true>(pointeeType,
+                                                               kind.value());
         });
 
       // Arbitrary optional types are not (yet) supported
@@ -978,19 +1019,31 @@ clang::QualType ClangTypeConverter::convertTemplateArgument(Type type) {
 
     if (auto kind = classifyPointer(boundGenericType))
       return withCache([&]() {
-        return convertPointerType(argType, kind.value(),
-                                  /*templateArgument=*/true);
+        return convertPointerType</*templateArgument=*/true>(argType,
+                                                             kind.value());
       });
 
     if (auto width = classifySIMD(boundGenericType))
       return withCache([&]() {
-        return convertSIMDType(argType, width.value(),
-                               /*templateArgument=*/true);
+        return convertSIMDType</*templateArgument=*/true>(argType,
+                                                          width.value());
       });
 
     return clang::QualType();
   }
 
+  if (auto functionType = type->getAs<FunctionType>()) {
+    return withCache([&]() {
+      return visitFunctionType</*templateArgument=*/true>(functionType);
+    });
+  }
+
+  if (auto functionType = type->getAs<SILFunctionType>()) {
+    return withCache([&]() {
+      return visitSILFunctionType</*templateArgument=*/true>(functionType);
+    });
+  }
+
   // Most types cannot be used to instantiate C++ function templates; give up.
   return clang::QualType();
 }
diff --git a/lib/AST/ClangTypeConverter.h b/lib/AST/ClangTypeConverter.h
index aaba8e8e28cd3..1cea5071cbd6f 100644
--- a/lib/AST/ClangTypeConverter.h
+++ b/lib/AST/ClangTypeConverter.h
@@ -70,11 +70,13 @@ class ClangTypeConverter :
   /// \returns The appropriate clang type on success, nullptr on failure.
   ///
   /// Precondition: The representation argument must be C-compatible.
-  const clang::Type *getFunctionType(
-    ArrayRef<AnyFunctionType::Param> params, Type resultTy,
-    AnyFunctionType::Representation repr);
+  template <bool templateArgument>
+  const clang::Type *getFunctionType(ArrayRef<AnyFunctionType::Param> params,
+                                     Type resultTy,
+                                     AnyFunctionType::Representation repr);
 
   /// Compute the C function type for a SIL function type.
+  template <bool templateArgument>
   const clang::Type *getFunctionType(ArrayRef<SILParameterInfo> params,
                                      std::optional<SILResultInfo> result,
                                      SILFunctionType::Representation repr);
@@ -125,11 +127,11 @@ class ClangTypeConverter :
 
   clang::QualType convertClangDecl(Type type, const clang::Decl *decl);
 
-  clang::QualType convertSIMDType(CanType scalarType, unsigned width,
-                                  bool templateArgument);
+  template <bool templateArgument>
+  clang::QualType convertSIMDType(CanType scalarType, unsigned width);
 
-  clang::QualType convertPointerType(CanType pointeeType, PointerKind kind,
-                                     bool templateArgument);
+  template <bool templateArgument>
+  clang::QualType convertPointerType(CanType pointeeType, PointerKind kind);
 
   void registerExportedClangDecl(Decl *swiftDecl,
                                  const clang::Decl *clangDecl);
@@ -148,14 +150,17 @@ class ClangTypeConverter :
   clang::QualType visitBoundGenericClassType(BoundGenericClassType *type);
   clang::QualType visitBoundGenericType(BoundGenericType *type);
   clang::QualType visitEnumType(EnumType *type);
+  template <bool templateArgument = false>
   clang::QualType visitFunctionType(FunctionType *type);
   clang::QualType visitProtocolCompositionType(ProtocolCompositionType *type);
   clang::QualType visitExistentialType(ExistentialType *type);
   clang::QualType visitBuiltinRawPointerType(BuiltinRawPointerType *type);
   clang::QualType visitBuiltinIntegerType(BuiltinIntegerType *type);
   clang::QualType visitBuiltinFloatType(BuiltinFloatType *type);
+  clang::QualType visitBuiltinVectorType(BuiltinVectorType *type);
   clang::QualType visitArchetypeType(ArchetypeType *type);
   clang::QualType visitDependentMemberType(DependentMemberType *type);
+  template <bool templateArgument = false>
   clang::QualType visitSILFunctionType(SILFunctionType *type);
   clang::QualType visitGenericTypeParamType(GenericTypeParamType *type);
   clang::QualType visitDynamicSelfType(DynamicSelfType *type);
diff --git a/lib/AST/Concurrency.cpp b/lib/AST/Concurrency.cpp
index 958ac706c692e..c2929dcf2c0dc 100644
--- a/lib/AST/Concurrency.cpp
+++ b/lib/AST/Concurrency.cpp
@@ -19,29 +19,35 @@
 
 using namespace swift;
 
-std::optional<DiagnosticBehavior>
-swift::getConcurrencyDiagnosticBehaviorLimit(NominalTypeDecl *nominal,
-                                             const DeclContext *fromDC,
-                                             bool ignoreExplicitConformance) {
-  ModuleDecl *importedModule = nullptr;
+ModuleDecl *swift::moduleImportForPreconcurrency(
+    NominalTypeDecl *nominal, const DeclContext *fromDC) {
+  // If the declaration itself has the @preconcurrency attribute,
+  // respect it.
   if (nominal->getAttrs().hasAttribute<PreconcurrencyAttr>()) {
-    // If the declaration itself has the @preconcurrency attribute,
-    // respect it.
-    importedModule = nominal->getParentModule();
-  } else {
-    // Determine whether this nominal type is visible via a @preconcurrency
-    // import.
-    auto import = nominal->findImport(fromDC);
-    auto sourceFile = fromDC->getParentSourceFile();
+    return nominal->getParentModule();
+  }
 
-    if (!import || !import->options.contains(ImportFlags::Preconcurrency))
-      return std::nullopt;
+  // Determine whether this nominal type is visible via a @preconcurrency
+  // import.
+  auto import = nominal->findImport(fromDC);
+  auto sourceFile = fromDC->getParentSourceFile();
 
-    if (sourceFile)
-      sourceFile->setImportUsedPreconcurrency(*import);
+  if (!import || !import->options.contains(ImportFlags::Preconcurrency))
+    return nullptr;
 
-    importedModule = import->module.importedModule;
-  }
+  if (sourceFile)
+    sourceFile->setImportUsedPreconcurrency(*import);
+
+  return import->module.importedModule;
+}
+
+std::optional<DiagnosticBehavior>
+swift::getConcurrencyDiagnosticBehaviorLimit(NominalTypeDecl *nominal,
+                                             const DeclContext *fromDC,
+                                             bool ignoreExplicitConformance) {
+  ModuleDecl *importedModule = moduleImportForPreconcurrency(nominal, fromDC);
+  if (!importedModule)
+    return std::nullopt;
 
   // When the type is explicitly non-Sendable, @preconcurrency imports
   // downgrade the diagnostic to a warning in Swift 6.
diff --git a/lib/AST/ConformanceLookup.cpp b/lib/AST/ConformanceLookup.cpp
index dc02e369d7da1..4a589f8cf2fda 100644
--- a/lib/AST/ConformanceLookup.cpp
+++ b/lib/AST/ConformanceLookup.cpp
@@ -66,6 +66,15 @@ swift::collectExistentialConformances(CanType fromType,
   return fromType->getASTContext().AllocateCopy(conformances);
 }
 
+static bool containsNonMarkerProtocols(ArrayRef<ProtocolDecl *> protocols) {
+  for (auto proto : protocols) {
+    if (!proto->isMarkerProtocol())
+      return true;
+  }
+
+  return false;
+}
+
 ProtocolConformanceRef
 swift::lookupExistentialConformance(Type type, ProtocolDecl *protocol) {
   ASTContext &ctx = protocol->getASTContext();
@@ -146,6 +155,12 @@ swift::lookupExistentialConformance(Type type, ProtocolDecl *protocol) {
   if (auto conformance = lookupSuperclassConformance(layout.getSuperclass()))
     return conformance;
 
+  // If the protocol is SendableMetatype, and there are no non-marker protocol
+  // requirements, allow it via self-conformance.
+  if (protocol->isSpecificProtocol(KnownProtocolKind::SendableMetatype) &&
+      !layout.containsNonMarkerProtocols())
+    return ProtocolConformanceRef(ctx.getSelfConformance(protocol));
+
   // We didn't find our protocol in the existential's list; it doesn't
   // conform.
   return ProtocolConformanceRef::forInvalid();
@@ -158,6 +173,10 @@ static bool shouldCreateMissingConformances(Type type, ProtocolDecl *proto) {
     return true;
   }
 
+  // SendableMetatype behaves similarly to Sendable.
+  if (proto->isSpecificProtocol(KnownProtocolKind::SendableMetatype))
+    return true;
+
   return false;
 }
 
@@ -250,8 +269,13 @@ static ProtocolConformanceRef getBuiltinTupleTypeConformance(
   return ProtocolConformanceRef::forMissingOrInvalid(type, protocol);
 }
 
+// We can end up checking builtin conformances for generic function types
+// when e.g. we're checking whether a captured local func declaration is
+// sendable. That's fine, we can answer that question in the abstract
+// without needing to generally support conformances on generic function
+// types.
 using EitherFunctionType =
-    llvm::PointerUnion<const SILFunctionType *, const FunctionType *>;
+    llvm::PointerUnion<const SILFunctionType *, const AnyFunctionType *>;
 
 /// Whether the given function type conforms to Sendable.
 static bool isSendableFunctionType(EitherFunctionType eitherFnTy) {
@@ -269,7 +293,7 @@ static bool isSendableFunctionType(EitherFunctionType eitherFnTy) {
     representation = *converted;
 
   } else {
-    auto functionType = eitherFnTy.get<const FunctionType *>();
+    auto functionType = cast<const AnyFunctionType *>(eitherFnTy);
 
     if (functionType->isSendable())
       return true;
@@ -295,7 +319,7 @@ static bool isEscapableFunctionType(EitherFunctionType eitherFnTy) {
 //    return !silFnTy->isNoEscape();
 //  }
 //
-//  auto functionType = eitherFnTy.get<const FunctionType *>();
+// auto functionType = cast<const FunctionType *>(eitherFnTy);
 //
 //  // TODO: what about autoclosures?
 //  return !functionType->isNoEscape();
@@ -313,7 +337,7 @@ static bool isBitwiseCopyableFunctionType(EitherFunctionType eitherFnTy) {
   if (auto silFnTy = eitherFnTy.dyn_cast<const SILFunctionType *>()) {
     representation = silFnTy->getRepresentation();
   } else {
-    auto fnTy = eitherFnTy.get<const FunctionType *>();
+    auto fnTy = cast<const AnyFunctionType *>(eitherFnTy);
     representation = convertRepresentation(fnTy->getRepresentation());
   }
 
@@ -377,6 +401,48 @@ static ProtocolConformanceRef getBuiltinFunctionTypeConformance(
   return ProtocolConformanceRef::forMissingOrInvalid(type, protocol);
 }
 
+/// Given the instance type of a metatype, determine whether the metatype is
+/// Sendable.
+///
+// Metatypes are generally Sendable, but with isolated conformances we
+// cannot assume that metatypes based on type parameters are Sendable.
+// Therefore, check for conformance to SendableMetatype.
+static bool metatypeWithInstanceTypeIsSendable(Type instanceType) {
+  ASTContext &ctx = instanceType->getASTContext();
+
+  // If we don't have the SendableMetatype protocol at all, just assume all
+  // metatypes are Sendable.
+  auto sendableMetatypeProto =
+      ctx.getProtocol(KnownProtocolKind::SendableMetatype);
+  if (!sendableMetatypeProto)
+    return true;
+
+  // If the instance type is a type parameter, it is not necessarily
+  // SendableMetatype. There will need to be a SendableMetatype requirement,
+  // but we do not have the generic environment to check that.
+  if (instanceType->isTypeParameter())
+    return false;
+
+  // If the instance type conforms to SendableMetatype, then its
+  // metatype is Sendable.
+  auto instanceConformance = lookupConformance(
+      instanceType, sendableMetatypeProto);
+  if (!instanceConformance.isInvalid() &&
+      !instanceConformance.hasMissingConformance())
+    return true;
+
+  // If this is an archetype that is non-SendableMetatype, but there are no
+  // non-marker protocol requirements that could carry conformances, treat
+  // the metatype as Sendable.
+  if (auto archetype = instanceType->getAs<ArchetypeType>()) {
+    if (!containsNonMarkerProtocols(archetype->getConformsTo()))
+      return true;
+  }
+
+  // The instance type is non-Sendable.
+  return false;
+}
+
 /// Synthesize a builtin metatype type conformance to the given protocol, if
 /// appropriate.
 static ProtocolConformanceRef getBuiltinMetaTypeTypeConformance(
@@ -387,31 +453,9 @@ static ProtocolConformanceRef getBuiltinMetaTypeTypeConformance(
   if (auto kp = protocol->getKnownProtocolKind()) {
     switch (*kp) {
     case KnownProtocolKind::Sendable:
-      // Metatypes are generally Sendable, but with isolated conformances we
-      // cannot assume that metatypes based on type parameters are Sendable.
-      // Therefore, check for conformance to SendableMetatype.
-      if (ctx.LangOpts.hasFeature(Feature::IsolatedConformances)) {
-        auto sendableMetatypeProto = 
-            ctx.getProtocol(KnownProtocolKind::SendableMetatype);
-        if (sendableMetatypeProto) {
-          Type instanceType = metatypeType->getInstanceType();
-
-          // If the instance type is a type parameter, it is not necessarily
-          // Sendable. There will need to be a Sendable requirement.
-          if (instanceType->isTypeParameter())
-            break;
-
-          // If the instance type conforms to SendableMetatype, then its
-          // metatype is Sendable.
-          auto instanceConformance = lookupConformance(
-              instanceType, sendableMetatypeProto);
-          if (instanceConformance.isInvalid() ||
-              instanceConformance.hasMissingConformance())
-            break;
-        }
+      if (!metatypeWithInstanceTypeIsSendable(metatypeType->getInstanceType()))
+        break;
 
-        // Every other metatype is Sendable.
-      }
       LLVM_FALLTHROUGH;
 
     case KnownProtocolKind::Copyable:
@@ -565,10 +609,9 @@ LookupConformanceInModuleRequest::evaluate(
   if (type->isTypeVariableOrMember())
     return ProtocolConformanceRef::forAbstract(type, protocol);
 
-  // UnresolvedType is a placeholder for an unknown type used when generating
-  // diagnostics.  We consider it to conform to all protocols, since the
-  // intended type might have. Same goes for PlaceholderType.
-  if (type->is<UnresolvedType>() || type->is<PlaceholderType>())
+  // PlaceholderType is a placeholder for an unknown type. We consider it to
+  // conform to all protocols, since the intended type might have.
+  if (type->is<PlaceholderType>())
     return ProtocolConformanceRef::forAbstract(type, protocol);
 
   // Pack types can conform to protocols.
@@ -582,7 +625,7 @@ LookupConformanceInModuleRequest::evaluate(
   }
 
   // Function types can conform to protocols.
-  if (auto functionType = type->getAs<FunctionType>()) {
+  if (auto functionType = type->getAs<AnyFunctionType>()) {
     return getBuiltinFunctionTypeConformance(type, functionType, protocol);
   }
 
@@ -853,68 +896,65 @@ bool TypeBase::isSendableType() {
 /// Copyable and Escapable checking utilities
 ///
 
-/// Preprocesses a type before querying whether it conforms to an invertible.
-static CanType preprocessTypeForInvertibleQuery(Type orig) {
-  Type type = orig;
-
-  // Strip off any StorageType wrapper.
-  type = type->getReferenceStorageReferent();
-
-  // Pack expansions such as `repeat T` themselves do not have conformances,
-  // so check its pattern type for conformance.
-  if (auto *pet = type->getAs<PackExpansionType>()) {
-    type = pet->getPatternType()->getCanonicalType();
-  }
-
-  // Strip @lvalue and canonicalize.
-  auto canType = type->getRValueType()->getCanonicalType();
-  return canType;
-}
-
 static bool conformsToInvertible(CanType type, InvertibleProtocolKind ip) {
-  auto &ctx = type->getASTContext();
-
-  auto *proto = ctx.getProtocol(getKnownProtocolKind(ip));
-  assert(proto && "missing Copyable/Escapable from stdlib!");
-
-  // Must not have a type parameter!
-  assert(!type->hasTypeParameter() && "caller forgot to mapTypeIntoContext!");
+  // FIXME: Remove these.
+  if (isa<SILPackType>(type))
+    return true;
 
-  assert(!type->hasUnboundGenericType() && "a UGT has no conformances!");
+  if (isa<SILTokenType>(type))
+    return true;
 
-  assert(!type->is<PackExpansionType>());
+  auto *proto = type->getASTContext().getProtocol(getKnownProtocolKind(ip));
+  ASSERT(proto);
 
-  // FIXME: lldb misbehaves by getting here with a SILPackType.
-  //  just pretend it it conforms.
-  if (type->is<SILPackType>())
-    return true;
+  return (bool) checkConformance(type, proto, /*allowMissing=*/false);
+}
 
-  if (type->is<SILTokenType>()) {
-    return true;
-  }
+void TypeBase::computeInvertibleConformances() {
+  Bits.TypeBase.ComputedInvertibleConformances = true;
 
-  // The SIL types in the AST do not have real conformances, and should have
-  // been handled in SILType instead.
-  assert(!(type->is<SILBoxType,
-                    SILMoveOnlyWrappedType,
-                    SILPackType,
-                    SILTokenType>()));
+  Type type(this);
 
-  const bool conforms =
-      (bool) checkConformance(type, proto, /*allowMissing=*/false);
+  // FIXME: Remove all of the below. Callers should be changed to perform any
+  // necessary unwrapping themselves.
 
-  return conforms;
+  // Pack expansions such as `repeat T` themselves do not have conformances,
+  // so check its pattern type for conformance.
+  if (auto *pet = type->getAs<PackExpansionType>())
+    type = pet->getPatternType();
+
+  auto canType = type->getReferenceStorageReferent()
+                     ->getWithoutSpecifierType()
+                     ->getCanonicalType();
+
+  assert(!canType->hasTypeParameter());
+  assert(!canType->hasUnboundGenericType());
+  assert(!isa<SILBoxType>(canType));
+  assert(!isa<SILMoveOnlyWrappedType>(canType));
+
+  Bits.TypeBase.IsCopyable = conformsToInvertible(
+      canType, InvertibleProtocolKind::Copyable);
+  Bits.TypeBase.IsEscapable = conformsToInvertible(
+      canType, InvertibleProtocolKind::Escapable);
 }
 
 /// \returns true iff this type lacks conformance to Copyable.
 bool TypeBase::isNoncopyable() {
-  auto canType = preprocessTypeForInvertibleQuery(this);
-  return !conformsToInvertible(canType, InvertibleProtocolKind::Copyable);
+  if (!Bits.TypeBase.ComputedInvertibleConformances)
+    computeInvertibleConformances();
+  return !Bits.TypeBase.IsCopyable;
+}
+
+/// \returns true iff this type conforms to Copyable.
+bool TypeBase::isCopyable() {
+  return !isNoncopyable();
 }
 
+/// \returns true iff this type conforms to Escaping.
 bool TypeBase::isEscapable() {
-  auto canType = preprocessTypeForInvertibleQuery(this);
-  return conformsToInvertible(canType, InvertibleProtocolKind::Escapable);
+  if (!Bits.TypeBase.ComputedInvertibleConformances)
+    computeInvertibleConformances();
+  return Bits.TypeBase.IsEscapable;
 }
 
 bool TypeBase::isEscapable(GenericSignature sig) {
@@ -924,3 +964,21 @@ bool TypeBase::isEscapable(GenericSignature sig) {
   }
   return contextTy->isEscapable();
 }
+
+bool TypeBase::isBitwiseCopyable() {
+  auto &ctx = getASTContext();
+  auto *bitwiseCopyableProtocol =
+    ctx.getProtocol(KnownProtocolKind::BitwiseCopyable);
+  if (!bitwiseCopyableProtocol) {
+    return false;
+  }
+  return (bool)checkConformance(this, bitwiseCopyableProtocol);
+}
+
+bool TypeBase::isBitwiseCopyable(GenericSignature sig) {
+  Type contextTy = this;
+  if (sig) {
+    contextTy = sig.getGenericEnvironment()->mapTypeIntoContext(contextTy);
+  }
+  return contextTy->isBitwiseCopyable();
+}
diff --git a/lib/AST/ConformanceLookupTable.cpp b/lib/AST/ConformanceLookupTable.cpp
index 46872a0c10e85..0a76d59a2464c 100644
--- a/lib/AST/ConformanceLookupTable.cpp
+++ b/lib/AST/ConformanceLookupTable.cpp
@@ -58,7 +58,7 @@ ProtocolDecl *ConformanceLookupTable::ConformanceEntry::getProtocol() const {
   if (auto protocol = Conformance.dyn_cast<ProtocolDecl *>())
     return protocol;
 
-  return Conformance.get<ProtocolConformance *>()->getProtocol();
+  return cast<ProtocolConformance *>(Conformance)->getProtocol();
 }
 
 void ConformanceLookupTable::ConformanceEntry::markSupersededBy(
@@ -149,13 +149,20 @@ void ConformanceLookupTable::destroy() {
 
 namespace {
   struct ConformanceConstructionInfo : public Located<ProtocolDecl *> {
+    /// The `TypeRepr` of the inheritance clause entry from which this nominal
+    /// was sourced, if any. For example, if this is a conformance to `Y`
+    /// declared as `struct S: X, Y & Z {}`, this is the `TypeRepr` for `Y & Z`.
+    TypeRepr *inheritedTypeRepr;
+
     ConformanceAttributes attributes;
 
     ConformanceConstructionInfo() { }
 
     ConformanceConstructionInfo(ProtocolDecl *item, SourceLoc loc,
+                                TypeRepr *inheritedTypeRepr,
                                 ConformanceAttributes attributes)
-        : Located(item, loc), attributes(attributes) {}
+        : Located(item, loc), inheritedTypeRepr(inheritedTypeRepr),
+          attributes(attributes) {}
   };
 }
 
@@ -210,8 +217,9 @@ void ConformanceLookupTable::forEachInStage(ConformanceStage stage,
       loader.first->loadAllConformances(next, loader.second, conformances);
       registerProtocolConformances(next, conformances);
       for (auto conf : conformances) {
-        protocols.push_back(
-            {conf->getProtocol(), SourceLoc(), ConformanceAttributes()});
+        protocols.push_back({conf->getProtocol(), SourceLoc(),
+                             /*inheritedTypeRepr=*/nullptr,
+                             ConformanceAttributes()});
       }
     } else if (next->getParentSourceFile() ||
                next->getParentModule()->isBuiltinModule()) {
@@ -220,7 +228,8 @@ void ConformanceLookupTable::forEachInStage(ConformanceStage stage,
       for (const auto &found :
                getDirectlyInheritedNominalTypeDecls(next, inverses, anyObject)) {
         if (auto proto = dyn_cast<ProtocolDecl>(found.Item))
-          protocols.push_back({proto, found.Loc, found.attributes});
+          protocols.push_back(
+              {proto, found.Loc, found.inheritedTypeRepr, found.attributes});
       }
     }
 
@@ -292,8 +301,6 @@ void ConformanceLookupTable::updateLookupTable(NominalTypeDecl *nominal,
     forEachInStage(
         stage, nominal,
         [&](NominalTypeDecl *nominal) {
-          auto source = ConformanceSource::forExplicit(nominal);
-
           // Get all of the protocols in the inheritance clause.
           InvertibleProtocolSet inverses;
           bool anyObject = false;
@@ -303,10 +310,12 @@ void ConformanceLookupTable::updateLookupTable(NominalTypeDecl *nominal,
             if (!proto)
               continue;
             auto kp = proto->getKnownProtocolKind();
-           assert(!found.isSuppressed ||
-                  kp.has_value() &&
-                      "suppressed conformance for non-known protocol!?");
+            assert(!found.isSuppressed ||
+                   kp.has_value() &&
+                       "suppressed conformance for non-known protocol!?");
             if (!found.isSuppressed) {
+              auto source = ConformanceSource::forExplicit(
+                  nominal, found.inheritedTypeRepr);
               addProtocol(
                   proto, found.Loc, source.withAttributes(found.attributes));
             }
@@ -318,11 +327,12 @@ void ConformanceLookupTable::updateLookupTable(NominalTypeDecl *nominal,
         [&](ExtensionDecl *ext, ArrayRef<ConformanceConstructionInfo> protos) {
           // The extension decl may not be validated, so we can't use
           // its inherited protocols directly.
-          auto source = ConformanceSource::forExplicit(ext);
-          for (auto locAndProto : protos)
-            addProtocol(
-                locAndProto.Item, locAndProto.Loc,
-                source.withAttributes(locAndProto.attributes));
+          for (auto locAndProto : protos) {
+            auto source = ConformanceSource::forExplicit(
+                ext, locAndProto.inheritedTypeRepr);
+            addProtocol(locAndProto.Item, locAndProto.Loc,
+                        source.withAttributes(locAndProto.attributes));
+          }
         });
     break;
 
@@ -599,6 +609,11 @@ ConformanceLookupTable::Ordering ConformanceLookupTable::compareConformances(
     }
   }
 
+  auto isUnavailable = [](DeclContext *dc) -> bool {
+    auto *ext = dyn_cast<ExtensionDecl>(dc);
+    return ext && ext->isUnavailable();
+  };
+
   // If only one of the conformances is unconditionally available on the
   // current deployment target, pick that one.
   //
@@ -610,7 +625,10 @@ ConformanceLookupTable::Ordering ConformanceLookupTable::compareConformances(
       rhs->getDeclContext()->isAlwaysAvailableConformanceContext()) {
     // Diagnose conflicting marker protocol conformances that differ in
     // un-availability.
-    diagnoseSuperseded = lhs->getProtocol()->isMarkerProtocol();
+    diagnoseSuperseded =
+      (lhs->getProtocol()->isMarkerProtocol() &&
+       isUnavailable(lhs->getDeclContext()) != isUnavailable(rhs->getDeclContext()) &&
+       (lhsKind != ConformanceEntryKind::Implied || rhsKind != ConformanceEntryKind::Implied));
 
     return (lhs->getDeclContext()->isAlwaysAvailableConformanceContext()
             ? Ordering::Before
@@ -862,8 +880,6 @@ DeclContext *ConformanceLookupTable::getConformingContext(
       Type classTy = nominal->getDeclaredInterfaceType();
       do {
         Type superclassTy = classTy->getSuperclassForDecl(superclassDecl);
-        if (superclassTy->is<ErrorType>())
-          return nullptr;
         auto inheritedConformance = swift::lookupConformance(
             superclassTy, protocol, /*allowMissing=*/false);
         if (inheritedConformance)
@@ -936,8 +952,6 @@ ConformanceLookupTable::getConformance(NominalTypeDecl *nominal,
     // declared.
     auto *conformingClass = cast<ClassDecl>(conformingNominal);
     Type superclassTy = type->getSuperclassForDecl(conformingClass);
-    if (superclassTy->is<ErrorType>())
-      return nullptr;
 
     // Look up the inherited conformance.
     auto inheritedConformance = swift::lookupConformance(
@@ -969,12 +983,17 @@ ConformanceLookupTable::getConformance(NominalTypeDecl *nominal,
       implyingConf = origImplyingConf->getRootNormalConformance();
     }
 
+    TypeRepr *inheritedTypeRepr = nullptr;
+    if (entry->Source.getKind() == ConformanceEntryKind::Explicit) {
+      inheritedTypeRepr = entry->Source.getInheritedTypeRepr();
+    }
+
     // Create or find the normal conformance.
     auto normalConf = ctx.getNormalConformance(
-        conformingType, protocol, conformanceLoc, conformingDC,
-        ProtocolConformanceState::Incomplete,
-        entry->Source.getOptions(),
-        entry->Source.getPreconcurrencyLoc());
+        conformingType, protocol, conformanceLoc, inheritedTypeRepr,
+        conformingDC, ProtocolConformanceState::Incomplete,
+        entry->Source.getOptions());
+
     // Invalid code may cause the getConformance call below to loop, so break
     // the infinite recursion by setting this eagerly to shortcircuit with the
     // early return at the start of this function.
@@ -1012,7 +1031,7 @@ ConformanceLookupTable::getConformance(NominalTypeDecl *nominal,
     }
   }
 
-  return entry->Conformance.get<ProtocolConformance *>();
+  return cast<ProtocolConformance *>(entry->Conformance);
 }
 
 void ConformanceLookupTable::addSynthesizedConformance(
@@ -1042,10 +1061,11 @@ void ConformanceLookupTable::registerProtocolConformance(
 
   // Otherwise, add a new entry.
   auto inherited = dyn_cast<InheritedProtocolConformance>(conformance);
-  ConformanceSource source
-    = inherited   ? ConformanceSource::forInherited(cast<ClassDecl>(nominal)) :
-      synthesized ? ConformanceSource::forSynthesized(dc) :
-                    ConformanceSource::forExplicit(dc);
+  ConformanceSource source =
+      inherited ? ConformanceSource::forInherited(cast<ClassDecl>(nominal))
+      : synthesized
+          ? ConformanceSource::forSynthesized(dc)
+          : ConformanceSource::forExplicit(dc, /*inheritedEntry=*/nullptr);
 
   ASTContext &ctx = nominal->getASTContext();
   ConformanceEntry *entry = new (ctx) ConformanceEntry(SourceLoc(),
diff --git a/lib/AST/ConformanceLookupTable.h b/lib/AST/ConformanceLookupTable.h
index 8199526975ce8..c2fe721651aa0 100644
--- a/lib/AST/ConformanceLookupTable.h
+++ b/lib/AST/ConformanceLookupTable.h
@@ -1,4 +1,4 @@
-//===--- ConformanceLookupTable - Conformance Lookup Table ------*- C++ -*-===//
+//===--- ConformanceLookupTable.h - Conformance Lookup Table ----*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -88,12 +88,20 @@ class ConformanceLookupTable : public ASTAllocated<ConformanceLookupTable> {
   class ConformanceSource {
     void *Storage;
 
+    /// The `TypeRepr` of the inheritance clause entry that declares this
+    /// conformance, if any. For example, if this is a conformance to `Y`
+    /// declared as `struct S: X, Y & Z {}`, this is the `TypeRepr` for `Y & Z`.
+    ///
+    /// - Important: The value can be valid only for an explicit conformance.
+    TypeRepr *inheritedTypeRepr;
+
     ConformanceEntryKind Kind;
 
     ConformanceAttributes attributes;
 
-    ConformanceSource(void *ptr, ConformanceEntryKind kind)
-      : Storage(ptr), Kind(kind) { }
+    ConformanceSource(void *ptr, ConformanceEntryKind kind,
+                      TypeRepr *inheritedTypeRepr = nullptr)
+        : Storage(ptr), inheritedTypeRepr(inheritedTypeRepr), Kind(kind) {}
 
   public:
     /// Create an inherited conformance.
@@ -109,8 +117,10 @@ class ConformanceLookupTable : public ASTAllocated<ConformanceLookupTable> {
     /// The given declaration context (nominal type declaration or
     /// extension thereof) explicitly specifies conformance to the
     /// protocol.
-    static ConformanceSource forExplicit(DeclContext *dc) {
-      return ConformanceSource(dc, ConformanceEntryKind::Explicit);
+    static ConformanceSource forExplicit(DeclContext *dc,
+                                         TypeRepr *inheritedEntry) {
+      return ConformanceSource(dc, ConformanceEntryKind::Explicit,
+                               inheritedEntry);
     }
 
     /// Create an implied conformance.
@@ -134,6 +144,13 @@ class ConformanceLookupTable : public ASTAllocated<ConformanceLookupTable> {
       return ConformanceSource(dc, ConformanceEntryKind::PreMacroExpansion);
     }
 
+    /// Return the `TypeRepr` of the inheritance clause entry that declares this
+    /// conformance, if any. For example, if this is a conformance to `Y`
+    /// declared as `struct S: X, Y & Z {}`, this is the `TypeRepr` for `Y & Z`.
+    ///
+    /// - Important: The value can be valid only for an explicit conformance.
+    TypeRepr *getInheritedTypeRepr() const { return inheritedTypeRepr; }
+
     /// Return a new conformance source with the given conformance
     /// attributes.
     ConformanceSource withAttributes(ConformanceAttributes attributes) {
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index cdacf78f9c0a0..8b24c6e4b830d 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -1,9 +1,8 @@
-
 //===--- Decl.cpp - Swift Language Decl ASTs ------------------------------===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,7 +14,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "swift/Strings.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTMangler.h"
@@ -24,6 +22,7 @@
 #include "swift/AST/AccessRequests.h"
 #include "swift/AST/AccessScope.h"
 #include "swift/AST/Attr.h"
+#include "swift/AST/AvailabilityContext.h"
 #include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/CaptureInfo.h"
 #include "swift/AST/ConformanceLookup.h"
@@ -64,6 +63,7 @@
 #include "swift/ClangImporter/ClangModule.h"
 #include "swift/Demangling/ManglingMacros.h"
 #include "swift/Parse/Lexer.h" // FIXME: Bad dependency
+#include "swift/Strings.h"
 #include "clang/Lex/MacroInfo.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
@@ -75,6 +75,7 @@
 
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/Module.h"
+#include "clang/Basic/TargetInfo.h"
 #include "clang/AST/Attr.h"
 #include "clang/AST/DeclObjC.h"
 
@@ -176,7 +177,6 @@ DescriptiveDeclKind Decl::getDescriptiveKind() const {
   TRIVIAL_KIND(InfixOperator);
   TRIVIAL_KIND(PrefixOperator);
   TRIVIAL_KIND(PostfixOperator);
-  TRIVIAL_KIND(TypeAlias);
   TRIVIAL_KIND(GenericTypeParam);
   TRIVIAL_KIND(AssociatedType);
   TRIVIAL_KIND(Protocol);
@@ -189,6 +189,12 @@ DescriptiveDeclKind Decl::getDescriptiveKind() const {
   TRIVIAL_KIND(MissingMember);
   TRIVIAL_KIND(Macro);
   TRIVIAL_KIND(MacroExpansion);
+  TRIVIAL_KIND(Using);
+
+  case DeclKind::TypeAlias:
+    return cast<TypeAliasDecl>(this)->getGenericParams()
+             ? DescriptiveDeclKind::GenericTypeAlias
+             : DescriptiveDeclKind::TypeAlias;
 
    case DeclKind::Enum:
      return cast<EnumDecl>(this)->getGenericParams()
@@ -285,6 +291,12 @@ DescriptiveDeclKind Decl::getDescriptiveKind() const {
 
      case AccessorKind::Init:
        return DescriptiveDeclKind::InitAccessor;
+
+     case AccessorKind::Borrow:
+       return DescriptiveDeclKind::BorrowAccessor;
+
+     case AccessorKind::Mutate:
+       return DescriptiveDeclKind::MutateAccessor;
      }
      llvm_unreachable("bad accessor kind");
    }
@@ -350,6 +362,7 @@ StringRef Decl::getDescriptiveKindName(DescriptiveDeclKind K) {
   ENTRY(PrefixOperator, "prefix operator");
   ENTRY(PostfixOperator, "postfix operator");
   ENTRY(TypeAlias, "type alias");
+  ENTRY(GenericTypeAlias, "generic type alias");
   ENTRY(GenericTypeParam, "generic parameter");
   ENTRY(AssociatedType, "associated type");
   ENTRY(Type, "type");
@@ -364,7 +377,6 @@ StringRef Decl::getDescriptiveKindName(DescriptiveDeclKind K) {
   ENTRY(GenericClass, "generic class");
   ENTRY(GenericActor, "generic actor");
   ENTRY(GenericDistributedActor, "generic distributed actor");
-  ENTRY(GenericType, "generic type");
   ENTRY(Subscript, "subscript");
   ENTRY(StaticSubscript, "static subscript");
   ENTRY(ClassSubscript, "class subscript");
@@ -395,6 +407,9 @@ StringRef Decl::getDescriptiveKindName(DescriptiveDeclKind K) {
   ENTRY(OpaqueVarType, "type");
   ENTRY(Macro, "macro");
   ENTRY(MacroExpansion, "pound literal");
+  ENTRY(Using, "using");
+  ENTRY(BorrowAccessor, "borrow accessor");
+  ENTRY(MutateAccessor, "Mutate accessor");
   }
 #undef ENTRY
   llvm_unreachable("bad DescriptiveDeclKind");
@@ -584,8 +599,7 @@ const Decl *Decl::getInnermostDeclWithAvailability() const {
   if (getAttrs().hasAttribute<AvailableAttr>())
     return this;
 
-  if (auto parent =
-          AvailabilityInference::parentDeclForInferredAvailability(this))
+  if (auto parent = parentDeclForAvailability())
     return parent->getInnermostDeclWithAvailability();
 
   return nullptr;
@@ -600,37 +614,51 @@ Decl::getIntroducedOSVersion(PlatformKind Kind) const {
   return std::nullopt;
 }
 
-std::optional<llvm::VersionTuple>
-Decl::getBackDeployedBeforeOSVersion(ASTContext &Ctx,
-                                     bool forTargetVariant) const {
+std::optional<std::pair<const BackDeployedAttr *, AvailabilityRange>>
+Decl::getBackDeployedAttrAndRange(ASTContext &Ctx,
+                                  bool forTargetVariant) const {
   if (auto *attr = getAttrs().getBackDeployed(Ctx, forTargetVariant)) {
-    auto version = attr->Version;
+    auto version = attr->getVersion();
     AvailabilityDomain ignoredDomain;
     AvailabilityInference::updateBeforeAvailabilityDomainForFallback(
         attr, getASTContext(), ignoredDomain, version);
 
     // If the remap for fallback resulted in 1.0, then the
     // backdeployment prior to that is not meaningful.
-    if (version == clang::VersionTuple(1, 0, 0, 0))
+    if (version == llvm::VersionTuple(1, 0, 0, 0))
       return std::nullopt;
 
-    return version;
+    return std::make_pair(attr, AvailabilityRange(version));
   }
 
   // Accessors may inherit `@backDeployed`.
   if (auto *AD = dyn_cast<AccessorDecl>(this))
-    return AD->getStorage()->getBackDeployedBeforeOSVersion(Ctx,
-                                                            forTargetVariant);
+    return AD->getStorage()->getBackDeployedAttrAndRange(Ctx, forTargetVariant);
 
   return std::nullopt;
 }
 
-bool Decl::isBackDeployed(ASTContext &Ctx) const {
-  if (getBackDeployedBeforeOSVersion(Ctx))
+bool Decl::isBackDeployed() const {
+  auto &Ctx = getASTContext();
+
+  // A function declared in a local context can never be back-deployed.
+  if (getDeclContext()->isLocalContext())
+    return false;
+
+  // A non-public function can never be back-deployed.
+  if (auto VD = dyn_cast<ValueDecl>(this)) {
+    auto access =
+        VD->getFormalAccessScope(/*useDC=*/nullptr,
+                                 /*treatUsableFromInlineAsPublic=*/true);
+    if (!access.isPublic())
+      return false;
+  }
+
+  if (getBackDeployedAttrAndRange(Ctx))
     return true;
 
   if (Ctx.LangOpts.TargetVariant) {
-    if (getBackDeployedBeforeOSVersion(Ctx, /*forTargetVariant=*/true))
+    if (getBackDeployedAttrAndRange(Ctx, /*forTargetVariant=*/true))
       return true;
   }
 
@@ -903,6 +931,17 @@ static ModuleDecl *getModuleContextForNameLookupForCxxDecl(const Decl *decl) {
   if (!ctx.LangOpts.EnableCXXInterop)
     return nullptr;
 
+  // When we clone members for base classes the cloned members have no
+  // corresponding Clang nodes. Look up the original imported declaration to
+  // figure out what Clang module does the cloned member originate from.
+  bool isClonedMember = false;
+  if (auto VD = dyn_cast<ValueDecl>(decl))
+    if (auto loader = ctx.getClangModuleLoader())
+      if (auto original = loader->getOriginalForClonedMember(VD)) {
+        isClonedMember = true;
+        decl = original;
+      }
+
   if (!decl->hasClangNode())
     return nullptr;
 
@@ -910,8 +949,11 @@ static ModuleDecl *getModuleContextForNameLookupForCxxDecl(const Decl *decl) {
 
   // We only need to look for the real parent module when the existing parent
   // is the imported header module.
-  if (!parentModule->isClangHeaderImportModule())
+  if (!parentModule->isClangHeaderImportModule()) {
+    if (isClonedMember)
+      return parentModule;
     return nullptr;
+  }
 
   auto clangModule = decl->getClangDecl()->getOwningModule();
   if (!clangModule)
@@ -1015,6 +1057,36 @@ bool Decl::isInMacroExpansionInContext() const {
   return file->getFulfilledMacroRole() != std::nullopt;
 }
 
+bool Decl::isInMacroExpansionFromClangHeader() const {
+  SourceLoc declLoc = getLoc();
+  if (declLoc.isInvalid())
+    return false;
+
+  auto &ctx = getASTContext();
+  auto &SourceMgr = ctx.SourceMgr;
+
+  auto declBufferID = SourceMgr.findBufferContainingLoc(declLoc);
+  auto declGeneratedSourceInfo = SourceMgr.getGeneratedSourceInfo(declBufferID);
+  if (!declGeneratedSourceInfo)
+    return false;
+  CustomAttr *attr = declGeneratedSourceInfo->attachedMacroCustomAttr;
+  if (!attr)
+    return false;
+
+  SourceLoc macroAttrLoc = attr->AtLoc;
+  if (macroAttrLoc.isInvalid())
+    return false;
+
+  auto macroAttrBufferID = SourceMgr.findBufferContainingLoc(macroAttrLoc);
+  auto macroAttrGeneratedSourceInfo =
+      SourceMgr.getGeneratedSourceInfo(macroAttrBufferID);
+  if (!macroAttrGeneratedSourceInfo)
+    return false;
+
+  return macroAttrGeneratedSourceInfo->kind ==
+         GeneratedSourceInfo::AttributeFromClang;
+}
+
 SourceLoc Decl::getLocFromSource() const {
   switch (getKind()) {
 #define DECL(ID, X) \
@@ -1092,7 +1164,7 @@ StringRef Decl::getAlternateModuleName() const {
   for (auto *Att: Attrs) {
     if (auto *OD = dyn_cast<OriginallyDefinedInAttr>(Att)) {
       if (!OD->isInvalid() && OD->isActivePlatform(getASTContext())) {
-        return OD->ManglingModuleName;
+        return OD->getManglingModuleName();
       }
     }
   }
@@ -1207,17 +1279,20 @@ ExplicitSafety Decl::getExplicitSafety() const {
   // If this declaration is from C, ask the Clang importer.
   if (auto clangDecl = getClangDecl()) {
     ASTContext &ctx = getASTContext();
-    return evaluateOrDefault(ctx.evaluator,
-                             ClangDeclExplicitSafety({clangDecl}),
-                             ExplicitSafety::Unspecified);
+    return evaluateOrDefault(
+        ctx.evaluator,
+        ClangDeclExplicitSafety({clangDecl, isa<ClassDecl>(this)}),
+        ExplicitSafety::Unspecified);
   }
   
-  // Inference: Check the enclosing context.
-  if (auto enclosingDC = getDeclContext()) {
-    // Is this an extension with @safe or @unsafe on it?
-    if (auto ext = dyn_cast<ExtensionDecl>(enclosingDC)) {
-      if (auto extSafety = getExplicitSafetyFromAttrs(ext))
-        return *extSafety;
+  // Inference: Check the enclosing context, unless this is a type.
+  if (!isa<TypeDecl>(this)) {
+    if (auto enclosingDC = getDeclContext()) {
+      // Is this an extension with @safe or @unsafe on it?
+      if (auto ext = dyn_cast<ExtensionDecl>(enclosingDC)) {
+        if (auto extSafety = getExplicitSafetyFromAttrs(ext))
+          return *extSafety;
+      }
     }
   }
 
@@ -1423,8 +1498,8 @@ AvailabilityRange Decl::getAvailabilityForLinkage() const {
 
   // When computing availability for linkage, use the "before" version from
   // the @backDeployed attribute, if present.
-  if (auto backDeployVersion = getBackDeployedBeforeOSVersion(ctx))
-    return AvailabilityRange{*backDeployVersion};
+  if (auto backDeployedAttrAndRange = getBackDeployedAttrAndRange(ctx))
+    return backDeployedAttrAndRange->second;
 
   auto containingContext = AvailabilityInference::annotatedAvailableRange(this);
   if (containingContext.has_value()) {
@@ -1439,7 +1514,7 @@ AvailabilityRange Decl::getAvailabilityForLinkage() const {
     return *containingContext;
   }
 
-  // FIXME: Adopt AvailabilityInference::parentDeclForInferredAvailability()
+  // FIXME: Adopt Decl::parentDeclForAvailability()
   // here instead of duplicating the logic.
   if (auto *accessor = dyn_cast<AccessorDecl>(this))
     return accessor->getStorage()->getAvailabilityForLinkage();
@@ -1462,9 +1537,9 @@ AvailabilityRange Decl::getAvailabilityForLinkage() const {
 
 bool Decl::isAlwaysWeakImported() const {
   // For a Clang declaration, trust Clang.
-  if (auto clangDecl = getClangDecl()) {
-    return clangDecl->isWeakImported();
-  }
+  if (auto clangDecl = getClangDecl())
+    return clangDecl->isWeakImported(
+        getASTContext().LangOpts.getMinPlatformVersion());
 
   if (getAttrs().hasAttribute<WeakLinkedAttr>())
     return true;
@@ -1568,8 +1643,7 @@ bool GenericContext::isComputingGenericSignature() const {
 
 /// If we hit a cycle while building the generic signature, we can't return
 /// nullptr, since this breaks invariants elsewhere. Instead, build a dummy
-/// signature where everything is Copyable and Escapable, to avoid spurious
-/// downstream diagnostics concerning move-only types.
+/// invalid signature to avoid spurious downstream diagnostics.
 static GenericSignature getPlaceholderGenericSignature(
     ASTContext &ctx, const DeclContext *DC) {
   SmallVector<GenericParamList *, 2> gpLists;
@@ -1585,22 +1659,13 @@ static GenericSignature getPlaceholderGenericSignature(
     gpLists[i]->setDepth(i);
 
   SmallVector<GenericTypeParamType *, 2> genericParams;
-  SmallVector<Requirement, 2> requirements;
-
   for (auto *gpList : gpLists) {
     for (auto *genericParam : *gpList) {
       auto type = genericParam->getDeclaredInterfaceType();
       genericParams.push_back(type->castTo<GenericTypeParamType>());
-
-      for (auto ip : InvertibleProtocolSet::allKnown()) {
-        auto proto = ctx.getProtocol(getKnownProtocolKind(ip));
-        requirements.emplace_back(RequirementKind::Conformance, type,
-                                  proto->getDeclaredInterfaceType());
-      }
     }
   }
-
-  return GenericSignature::get(genericParams, requirements);
+  return GenericSignature::forInvalid(genericParams);
 }
 
 GenericSignature GenericContext::getGenericSignature() const {
@@ -1656,8 +1721,7 @@ ImportDecl::ImportDecl(DeclContext *DC, SourceLoc ImportLoc, ImportKind K,
   assert(Bits.ImportDecl.NumPathElements == Path.size() && "Truncation error");
   Bits.ImportDecl.ImportKind = static_cast<unsigned>(K);
   assert(getImportKind() == K && "not enough bits for ImportKind");
-  std::uninitialized_copy(Path.begin(), Path.end(),
-                          getTrailingObjects<ImportPath::Element>());
+  std::uninitialized_copy(Path.begin(), Path.end(), getTrailingObjects());
 }
 
 ImportKind ImportDecl::getBestImportKind(const ValueDecl *VD) {
@@ -1674,6 +1738,7 @@ ImportKind ImportDecl::getBestImportKind(const ValueDecl *VD) {
   case DeclKind::Missing:
   case DeclKind::MissingMember:
   case DeclKind::MacroExpansion:
+  case DeclKind::Using:
     llvm_unreachable("not a ValueDecl");
 
   case DeclKind::AssociatedType:
@@ -1801,6 +1866,30 @@ bool ImportDecl::isAccessLevelImplicit() const {
   return true;
 }
 
+UsingDecl::UsingDecl(SourceLoc usingLoc, SourceLoc specifierLoc,
+                     UsingSpecifier specifier, DeclContext *parent)
+    : Decl(DeclKind::Using, parent), UsingLoc(usingLoc),
+      SpecifierLoc(specifierLoc) {
+  Bits.UsingDecl.Specifier = static_cast<unsigned>(specifier);
+  assert(getSpecifier() == specifier &&
+         "not enough bits in UsingDecl flags for specifier");
+}
+
+std::string UsingDecl::getSpecifierName() const {
+  switch (getSpecifier()) {
+  case UsingSpecifier::MainActor:
+    return "@MainActor";
+  case UsingSpecifier::Nonisolated:
+    return "nonisolated";
+  }
+}
+
+UsingDecl *UsingDecl::create(ASTContext &ctx, SourceLoc usingLoc,
+                             SourceLoc specifierLoc, UsingSpecifier specifier,
+                             DeclContext *parent) {
+  return new (ctx) UsingDecl(usingLoc, specifierLoc, specifier, parent);
+}
+
 void NominalTypeDecl::setConformanceLoader(LazyMemberLoader *lazyLoader,
                                            uint64_t contextData) {
   assert(!Bits.NominalTypeDecl.HasLazyConformances &&
@@ -1863,7 +1952,7 @@ InheritedTypes::InheritedTypes(
   if (auto *typeDecl = decl.dyn_cast<const TypeDecl *>()) {
     Entries = typeDecl->Inherited;
   } else {
-    Entries = decl.get<const ExtensionDecl *>()->Inherited;
+    Entries = cast<const ExtensionDecl *>(decl)->Inherited;
   }
 }
 
@@ -1884,7 +1973,7 @@ ASTContext &InheritedTypes::getASTContext() const {
   if (auto typeDecl = Decl.dyn_cast<const TypeDecl *>()) {
     return typeDecl->getASTContext();
   } else {
-    return Decl.get<const ExtensionDecl *>()->getASTContext();
+    return cast<const ExtensionDecl *>(Decl)->getASTContext();
   }
 }
 
@@ -1896,7 +1985,7 @@ SourceLoc InheritedTypes::getColonLoc() const {
   if (auto typeDecl = Decl.dyn_cast<const TypeDecl *>()) {
     precedingTok = typeDecl->getNameLoc();
   } else {
-    auto *ext = Decl.get<const ExtensionDecl *>();
+    auto *ext = cast<const ExtensionDecl *>(Decl);
     precedingTok = ext->getSourceRange().End;
   }
 
@@ -1937,9 +2026,9 @@ SourceRange InheritedTypes::getRemovalRange(unsigned i) const {
 
 Type InheritedTypes::getResolvedType(unsigned i,
                                      TypeResolutionStage stage) const {
-  ASTContext &ctx = Decl.is<const ExtensionDecl *>()
-                        ? Decl.get<const ExtensionDecl *>()->getASTContext()
-                        : Decl.get<const TypeDecl *>()->getASTContext();
+  ASTContext &ctx = isa<const ExtensionDecl *>(Decl)
+                        ? cast<const ExtensionDecl *>(Decl)->getASTContext()
+                        : cast<const TypeDecl *>(Decl)->getASTContext();
   return evaluateOrDefault(ctx.evaluator, InheritedTypeRequest{Decl, i, stage},
                            InheritedTypeResult::forDefault())
       .getInheritedTypeOrNull(getASTContext());
@@ -2005,21 +2094,8 @@ ExtensionDecl::takeConformanceLoaderSlow() {
 }
 
 NominalTypeDecl *ExtensionDecl::getExtendedNominal() const {
-  if (hasBeenBound()) {
-    return ExtendedNominal.getPointer();
-  } else if (canNeverBeBound()) {
-    return computeExtendedNominal();
-  }
-
-  llvm_unreachable(
-      "Extension must have already been bound (by bindExtensions)");
-}
-
-NominalTypeDecl *ExtensionDecl::computeExtendedNominal() const {
-  ASTContext &ctx = getASTContext();
-  return evaluateOrDefault(
-      ctx.evaluator, ExtendedNominalRequest{const_cast<ExtensionDecl *>(this)},
-      nullptr);
+  auto &eval = getASTContext().evaluator;
+  return evaluateOrDefault(eval, ExtendedNominalRequest{this}, nullptr);
 }
 
 bool ExtensionDecl::canNeverBeBound() const {
@@ -2101,10 +2177,13 @@ bool ExtensionDecl::isWrittenWithConstraints() const {
   return false;
 }
 
-bool ExtensionDecl::isInSameDefiningModule() const {
+bool ExtensionDecl::isInSameDefiningModule(
+    bool RespectOriginallyDefinedIn) const {
   auto decl = getExtendedNominal();
-  auto extensionAlterName = getAlternateModuleName();
-  auto typeAlterName = decl->getAlternateModuleName();
+  auto extensionAlterName =
+      RespectOriginallyDefinedIn ? getAlternateModuleName() : "";
+  auto typeAlterName =
+      RespectOriginallyDefinedIn ? decl->getAlternateModuleName() : "";
 
   if (!extensionAlterName.empty()) {
     if (!typeAlterName.empty()) {
@@ -2183,6 +2262,10 @@ bool Decl::isObjCImplementation() const {
   return getAttrs().hasAttribute<ObjCImplementationAttr>(/*AllowInvalid=*/true);
 }
 
+bool Decl::isNeverEmittedIntoClient() const {
+  return getAttrs().hasAttribute<NeverEmitIntoClientAttr>();
+}
+
 PatternBindingDecl::PatternBindingDecl(SourceLoc StaticLoc,
                                        StaticSpellingKind StaticSpelling,
                                        SourceLoc VarLoc,
@@ -2240,7 +2323,7 @@ PatternBindingDecl::create(ASTContext &Ctx, SourceLoc StaticLoc,
                                           PatternList.size(), Parent);
   // Set up the patterns.
   std::uninitialized_copy(PatternList.begin(), PatternList.end(),
-                          PBD->getTrailingObjects<PatternBindingEntry>());
+                          PBD->getTrailingObjects());
 
   for (auto idx : range(PBD->getNumPatternEntries())) {
     auto *initContext = PBD->getInitContext(idx);
@@ -2287,6 +2370,13 @@ PatternBindingDecl *PatternBindingDecl::createDeserialized(
   return PBD;
 }
 
+CaptureInfo PatternBindingDecl::getCaptureInfo(unsigned i) const {
+  auto *mutableThis = const_cast<PatternBindingDecl *>(this);
+  PatternBindingCaptureInfoRequest req(mutableThis, i);
+  return evaluateOrDefault(getASTContext().evaluator, req,
+                           CaptureInfo::empty());
+}
+
 PatternBindingInitializer *
 PatternBindingInitializer::createDeserialized(PatternBindingDecl *PBD,
                                               unsigned index) {
@@ -2484,6 +2574,19 @@ StringRef PatternBindingEntry::getInitStringRepresentation(
   return extractInlinableText(ctx, init, scratch);
 }
 
+SourceLoc PatternBindingDecl::getStartLoc() const {
+  if (StaticLoc.isValid())
+    return StaticLoc;
+
+  if (VarLoc.isValid())
+    return VarLoc;
+
+  if (getPatternList().empty())
+    return SourceLoc();
+
+  return getPatternList().front().getStartLoc();
+}
+
 SourceRange PatternBindingDecl::getSourceRange() const {
   SourceLoc startLoc = getStartLoc();
   SourceLoc endLoc = getPatternList().empty()
@@ -2587,10 +2690,16 @@ bool PatternBindingDecl::hasStorage() const {
 
 const PatternBindingEntry *
 PatternBindingDecl::getCheckedPatternBindingEntry(unsigned i) const {
-  return evaluateOrDefault(
+  auto result = evaluateOrDefault(
       getASTContext().evaluator,
       PatternBindingEntryRequest{const_cast<PatternBindingDecl *>(this), i},
       nullptr);
+
+  // If we ran into a cycle, we can still return the entry.
+  if (!result)
+    return &getPatternList()[i];
+
+  return result;
 }
 
 void PatternBindingDecl::setPattern(unsigned i, Pattern *P,
@@ -2973,6 +3082,9 @@ getDirectReadAccessStrategy(const AbstractStorageDecl *storage) {
   case ReadImplKind::Read2:
     return AccessStrategy::getAccessor(AccessorKind::Read2,
                                        /*dispatch*/ false);
+  case ReadImplKind::Borrow:
+    return AccessStrategy::getAccessor(AccessorKind::Borrow,
+                                       /*dispatch*/ false);
   }
   llvm_unreachable("bad impl kind");
 }
@@ -3011,13 +3123,18 @@ getDirectWriteAccessStrategy(const AbstractStorageDecl *storage) {
   case WriteImplKind::Modify2:
     return AccessStrategy::getAccessor(AccessorKind::Modify2,
                                        /*dispatch*/ false);
+  case WriteImplKind::Mutate:
+    return AccessStrategy::getAccessor(AccessorKind::Mutate,
+                                       /*dispatch*/ false);
   }
   llvm_unreachable("bad impl kind");
 }
 
-static AccessStrategy
-getOpaqueReadAccessStrategy(const AbstractStorageDecl *storage, bool dispatch,
-                            bool useOldABI);
+static AccessStrategy getOpaqueReadAccessStrategy(
+    const AbstractStorageDecl *storage, bool dispatch, ModuleDecl *module,
+    ResilienceExpansion expansion,
+    std::optional<std::pair<SourceRange, const DeclContext *>> location,
+    bool useOldABI);
 static AccessStrategy
 getOpaqueWriteAccessStrategy(const AbstractStorageDecl *storage, bool dispatch);
 
@@ -3032,7 +3149,9 @@ getDirectReadWriteAccessStrategy(const AbstractStorageDecl *storage) {
     // If the storage isDynamic (and not @objc) use the accessors.
     if (storage->shouldUseNativeDynamicDispatch())
       return AccessStrategy::getMaterializeToTemporary(
-          getOpaqueReadAccessStrategy(storage, false, false),
+          getOpaqueReadAccessStrategy(storage, false, nullptr,
+                                      ResilienceExpansion::Minimal,
+                                      std::nullopt, false),
           getOpaqueWriteAccessStrategy(storage, false));
     return AccessStrategy::getStorage();
   }
@@ -3065,19 +3184,68 @@ getDirectReadWriteAccessStrategy(const AbstractStorageDecl *storage) {
     return AccessStrategy::getMaterializeToTemporary(
                                        getDirectReadAccessStrategy(storage),
                                        getDirectWriteAccessStrategy(storage));
+  case ReadWriteImplKind::Mutate:
+    return AccessStrategy::getAccessor(AccessorKind::Mutate,
+                                       /*dispatch*/ false);
   }
   llvm_unreachable("bad impl kind");
 }
 
-static AccessStrategy
-getOpaqueReadAccessStrategy(const AbstractStorageDecl *storage, bool dispatch,
-                            bool useOldABI) {
+static bool mayReferenceUseCoroutineAccessorOnStorage(
+    ModuleDecl *module, ResilienceExpansion expansion,
+    std::optional<std::pair<SourceRange, const DeclContext *>> reference,
+    const AbstractStorageDecl *storage) {
+  assert(storage);
+  ASTContext &ctx = storage->getASTContext();
+  assert(ctx.LangOpts.hasFeature(Feature::CoroutineAccessors));
+
+  // For triples without platforms, coroutine accessors are always available.
+  auto domain = ctx.getTargetAvailabilityDomain();
+  if (domain.isUniversal())
+    return true;
+
+  // A non-resilient access to storage can always use the coroutine accessor,
+  // provided it exists.  Such an access is compiled with the version of the
+  // module that includes the accessor.
+  bool resilient = [&] {
+    if (module)
+      return storage->isResilient(module, expansion);
+    else
+      return storage->isResilient();
+  }();
+  if (!resilient)
+    return true;
+
+  // Without knowing where the storage is referenced, it can't be known that
+  // a coroutine accessor is available.
+  if (!reference) {
+    return false;
+  }
+
+  // A resilient access to storage may only use a coroutine accessor if the
+  // storage became available no earlier than the feature.
+  auto referenceAvailability = AvailabilityContext::forLocation(
+                                   reference->first.Start, reference->second)
+                                   .getPlatformRange();
+  auto featureAvailability =
+      storage->getASTContext().getCoroutineAccessorsAvailability();
+
+  return referenceAvailability.isContainedIn(featureAvailability);
+}
+
+static AccessStrategy getOpaqueReadAccessStrategy(
+    const AbstractStorageDecl *storage, bool dispatch, ModuleDecl *module,
+    ResilienceExpansion expansion,
+    std::optional<std::pair<SourceRange, const DeclContext *>> location,
+    bool useOldABI) {
   if (useOldABI) {
     assert(storage->requiresOpaqueRead2Coroutine());
     assert(storage->requiresOpaqueReadCoroutine());
     return AccessStrategy::getAccessor(AccessorKind::Read, dispatch);
   }
-  if (storage->requiresOpaqueRead2Coroutine())
+  if (storage->requiresOpaqueRead2Coroutine() &&
+      mayReferenceUseCoroutineAccessorOnStorage(module, expansion, location,
+                                                storage))
     return AccessStrategy::getAccessor(AccessorKind::Read2, dispatch);
   if (storage->requiresOpaqueReadCoroutine())
     return AccessStrategy::getAccessor(AccessorKind::Read, dispatch);
@@ -3091,41 +3259,53 @@ getOpaqueWriteAccessStrategy(const AbstractStorageDecl *storage, bool dispatch)
   return AccessStrategy::getAccessor(AccessorKind::Set, dispatch);
 }
 
-static AccessStrategy
-getOpaqueReadWriteAccessStrategy(const AbstractStorageDecl *storage,
-                                 bool dispatch, bool useOldABI) {
+static AccessStrategy getOpaqueReadWriteAccessStrategy(
+    const AbstractStorageDecl *storage, bool dispatch, ModuleDecl *module,
+    ResilienceExpansion expansion,
+    std::optional<std::pair<SourceRange, const DeclContext *>> location,
+    bool useOldABI) {
   if (useOldABI) {
     assert(storage->requiresOpaqueModify2Coroutine());
     assert(storage->requiresOpaqueModifyCoroutine());
     return AccessStrategy::getAccessor(AccessorKind::Modify, dispatch);
   }
-  if (storage->requiresOpaqueModify2Coroutine())
+  if (storage->requiresOpaqueModify2Coroutine() &&
+      mayReferenceUseCoroutineAccessorOnStorage(module, expansion, location,
+                                                storage))
     return AccessStrategy::getAccessor(AccessorKind::Modify2, dispatch);
   if (storage->requiresOpaqueModifyCoroutine())
     return AccessStrategy::getAccessor(AccessorKind::Modify, dispatch);
   return AccessStrategy::getMaterializeToTemporary(
-      getOpaqueReadAccessStrategy(storage, dispatch, false),
+      getOpaqueReadAccessStrategy(storage, dispatch, nullptr,
+                                  ResilienceExpansion::Minimal, location,
+                                  false),
       getOpaqueWriteAccessStrategy(storage, dispatch));
 }
 
-static AccessStrategy
-getOpaqueAccessStrategy(const AbstractStorageDecl *storage,
-                        AccessKind accessKind, bool dispatch, bool useOldABI) {
+static AccessStrategy getOpaqueAccessStrategy(
+    const AbstractStorageDecl *storage, AccessKind accessKind, bool dispatch,
+    ModuleDecl *module, ResilienceExpansion expansion,
+    std::optional<std::pair<SourceRange, const DeclContext *>> location,
+    bool useOldABI) {
   switch (accessKind) {
   case AccessKind::Read:
-    return getOpaqueReadAccessStrategy(storage, dispatch, useOldABI);
+    return getOpaqueReadAccessStrategy(storage, dispatch, module, expansion,
+                                       location, useOldABI);
   case AccessKind::Write:
     assert(!useOldABI);
     return getOpaqueWriteAccessStrategy(storage, dispatch);
   case AccessKind::ReadWrite:
-    return getOpaqueReadWriteAccessStrategy(storage, dispatch, useOldABI);
+    return getOpaqueReadWriteAccessStrategy(storage, dispatch, module,
+                                            expansion, location, useOldABI);
   }
   llvm_unreachable("bad access kind");
 }
 
 AccessStrategy AbstractStorageDecl::getAccessStrategy(
     AccessSemantics semantics, AccessKind accessKind, ModuleDecl *module,
-    ResilienceExpansion expansion, bool useOldABI) const {
+    ResilienceExpansion expansion,
+    std::optional<std::pair<SourceRange, const DeclContext *>> location,
+    bool useOldABI) const {
   switch (semantics) {
   case AccessSemantics::DirectToStorage:
     assert(hasStorage() || getASTContext().Diags.hadAnyError());
@@ -3142,11 +3322,11 @@ AccessStrategy AbstractStorageDecl::getAccessStrategy(
       // accessors are dynamically dispatched, and we cannot do direct access.
       if (isPolymorphic(this))
         return getOpaqueAccessStrategy(this, accessKind, /*dispatch*/ true,
-                                       useOldABI);
+                                       module, expansion, location, useOldABI);
 
       if (shouldUseNativeDynamicDispatch())
         return getOpaqueAccessStrategy(this, accessKind, /*dispatch*/ false,
-                                       useOldABI);
+                                       module, expansion, location, useOldABI);
 
       // If the storage is resilient from the given module and resilience
       // expansion, we cannot use direct access.
@@ -3169,7 +3349,7 @@ AccessStrategy AbstractStorageDecl::getAccessStrategy(
 
       if (resilient)
         return getOpaqueAccessStrategy(this, accessKind, /*dispatch*/ false,
-                                       useOldABI);
+                                       module, expansion, location, useOldABI);
     }
 
     LLVM_FALLTHROUGH;
@@ -3189,6 +3369,15 @@ AccessStrategy AbstractStorageDecl::getAccessStrategy(
   llvm_unreachable("bad access semantics");
 }
 
+bool AbstractStorageDecl::isAccessedViaPhysicalStorage(
+    AccessSemantics semantics, AccessKind accessKind, ModuleDecl *module,
+    ResilienceExpansion expansion) const {
+  return getAccessStrategy(semantics, accessKind, module, expansion,
+                           /*location=*/std::nullopt,
+                           /*useOldABI=*/false)
+             .getKind() == AccessStrategy::Kind::Storage;
+}
+
 bool AbstractStorageDecl::requiresOpaqueAccessors() const {
   // Subscripts always require opaque accessors, so don't even kick off
   // a request.
@@ -3220,19 +3409,35 @@ bool AbstractStorageDecl::requiresOpaqueAccessor(AccessorKind kind) const {
 
   // Other accessors are never part of the opaque-accessors set.
 #define OPAQUE_ACCESSOR(ID, KEYWORD)
-#define ACCESSOR(ID) \
-  case AccessorKind::ID:
+#define ACCESSOR(ID, KEYWORD) case AccessorKind::ID:
 #include "swift/AST/AccessorKinds.def"
     return false;
   }
   llvm_unreachable("bad accessor kind");
 }
 
+bool AbstractStorageDecl::requiresOpaqueSetter() const {
+  if (!supportsMutation()) {
+    return false;
+  }
+
+  // If a mutate accessor is present, we don't need a setter.
+  if (getAccessor(AccessorKind::Mutate)) {
+    return false;
+  }
+  return true;
+}
+
 bool AbstractStorageDecl::requiresOpaqueReadCoroutine() const {
   ASTContext &ctx = getASTContext();
   if (ctx.LangOpts.hasFeature(Feature::CoroutineAccessors))
     return requiresCorrespondingUnderscoredCoroutineAccessor(
         AccessorKind::Read2);
+
+  // If a borrow accessor is present, we don't need a read coroutine.
+  if (getAccessor(AccessorKind::Borrow)) {
+    return false;
+  }
   return getOpaqueReadOwnership() != OpaqueReadOwnership::Owned;
 }
 
@@ -3240,6 +3445,11 @@ bool AbstractStorageDecl::requiresOpaqueRead2Coroutine() const {
   ASTContext &ctx = getASTContext();
   if (!ctx.LangOpts.hasFeature(Feature::CoroutineAccessors))
     return false;
+
+  // If a borrow accessor is present, we don't need a read coroutine.
+  if (getAccessor(AccessorKind::Borrow)) {
+    return false;
+  }
   return getOpaqueReadOwnership() != OpaqueReadOwnership::Owned;
 }
 
@@ -3524,6 +3734,7 @@ bool ValueDecl::isInstanceMember() const {
   case DeclKind::Missing:
   case DeclKind::MissingMember:
   case DeclKind::MacroExpansion:
+  case DeclKind::Using:
     llvm_unreachable("Not a ValueDecl");
 
   case DeclKind::Class:
@@ -3775,6 +3986,13 @@ bool swift::conflicting(ASTContext &ctx,
   if (sig1.IsFunction != sig2.IsFunction)
     return true;
 
+  // Gracefully handle the case where value generic arguments were introduced
+  // as a conflicting value with static variables of the same name.
+  if (sig1.IsGenericArg != sig2.IsGenericArg) {
+    *wouldConflictInSwift5 = true;
+    return true;
+  }
+
   // Variables always conflict with non-variables with the same signature.
   // (e.g variables with zero argument functions, variables with type
   //  declarations)
@@ -3953,6 +4171,7 @@ OverloadSignature ValueDecl::getOverloadSignature() const {
   signature.IsNominal = isa<NominalTypeDecl>(this);
   signature.IsTypeAlias = isa<TypeAliasDecl>(this);
   signature.IsMacro = isa<MacroDecl>(this);
+  signature.IsGenericArg = isa<GenericTypeParamDecl>(this);
   signature.HasOpaqueReturnType =
                        !signature.IsVariable && (bool)getOpaqueResultTypeDecl();
 
@@ -4407,7 +4626,10 @@ StringRef ValueDecl::getCDeclName() const {
 
   // Handle explicit cdecl attributes.
   if (auto cdeclAttr = getAttrs().getAttribute<CDeclAttr>()) {
-    return cdeclAttr->Name;
+    if (!cdeclAttr->Name.empty())
+      return cdeclAttr->Name;
+    else
+      return getBaseIdentifier().str();
   }
 
   return "";
@@ -4629,6 +4851,7 @@ SourceLoc Decl::getAttributeInsertionLoc(bool forModifier) const {
   case DeclKind::MissingMember:
   case DeclKind::MacroExpansion:
   case DeclKind::BuiltinTuple:
+  case DeclKind::Using:
     // These don't take attributes.
     return SourceLoc();
 
@@ -4702,6 +4925,25 @@ SourceLoc Decl::getAttributeInsertionLoc(bool forModifier) const {
   return resultLoc;
 }
 
+bool ValueDecl::hasAttributeWithInlinableSemantics() const {
+  if (getAttrs().hasAttribute<InlinableAttr>())
+    return true;
+
+  // @inline(always) implies @inlinable on "public" (open, public, package)
+  // declarations.
+  AccessScope access =
+        getFormalAccessScope(nullptr, /*treatUsableFromInlineAsPublic*/false);
+  if (!access.isPublicOrPackage())
+    return false;
+
+  if (auto *inlineAttr = getAttrs().getAttribute<InlineAttr>()) {
+    if (inlineAttr && inlineAttr->getKind() == InlineKind::Always)
+      return true;
+  }
+
+  return false;
+}
+
 /// Returns true if \p VD needs to be treated as publicly-accessible
 /// at the SIL, LLVM, and machine levels due to being @usableFromInline.
 bool ValueDecl::isUsableFromInline() const {
@@ -4714,14 +4956,14 @@ bool ValueDecl::isUsableFromInline() const {
 
   if (getAttrs().hasAttribute<UsableFromInlineAttr>() ||
       getAttrs().hasAttribute<AlwaysEmitIntoClientAttr>() ||
-      getAttrs().hasAttribute<InlinableAttr>())
+      hasAttributeWithInlinableSemantics())
     return true;
 
   if (auto *accessor = dyn_cast<AccessorDecl>(this)) {
     auto *storage = accessor->getStorage();
     if (storage->getAttrs().hasAttribute<UsableFromInlineAttr>() ||
         storage->getAttrs().hasAttribute<AlwaysEmitIntoClientAttr>() ||
-        storage->getAttrs().hasAttribute<InlinableAttr>())
+        storage->hasAttributeWithInlinableSemantics())
       return true;
   }
 
@@ -4729,7 +4971,7 @@ bool ValueDecl::isUsableFromInline() const {
     if (auto *namingDecl = opaqueType->getNamingDecl()) {
       if (namingDecl->getAttrs().hasAttribute<UsableFromInlineAttr>() ||
           namingDecl->getAttrs().hasAttribute<AlwaysEmitIntoClientAttr>() ||
-          namingDecl->getAttrs().hasAttribute<InlinableAttr>())
+          namingDecl->hasAttributeWithInlinableSemantics())
         return true;
     }
   }
@@ -5348,7 +5590,7 @@ void ValueDecl::copyFormalAccessFrom(const ValueDecl *source,
   // Inherit the @usableFromInline attribute.
   if (source->getAttrs().hasAttribute<UsableFromInlineAttr>() &&
       !getAttrs().hasAttribute<UsableFromInlineAttr>() &&
-      !getAttrs().hasAttribute<InlinableAttr>() &&
+      !hasAttributeWithInlinableSemantics() &&
       DeclAttribute::canAttributeAppearOnDecl(DeclAttrKind::UsableFromInline,
                                               this)) {
     auto &ctx = getASTContext();
@@ -5947,9 +6189,13 @@ GenericTypeParamDecl *GenericTypeParamDecl::createImplicit(
 }
 
 Type GenericTypeParamDecl::getValueType() const {
-  return evaluateOrDefault(getASTContext().evaluator,
-    GenericTypeParamDeclGetValueTypeRequest{const_cast<GenericTypeParamDecl *>(this)},
-    Type());
+  if (!isValue())
+    return Type();
+
+  auto &ctx = getASTContext();
+  GenericTypeParamDeclGetValueTypeRequest req(this);
+  auto ty = evaluateOrDefault(ctx.evaluator, req, Type());
+  return ty ? ty : ErrorType::get(ctx);
 }
 
 SourceRange GenericTypeParamDecl::getSourceRange() const {
@@ -6198,6 +6444,9 @@ ConstructorDecl *NominalTypeDecl::getDefaultInitializer() const {
 }
 
 void NominalTypeDecl::synthesizeSemanticMembersIfNeeded(DeclName member) {
+  if (isa<ProtocolDecl>(this))
+    return;
+
   // Silently break cycles here because we can't be sure when and where a
   // request to synthesize will come from yet.
   // FIXME: rdar://56844567
@@ -6854,14 +7103,11 @@ bool EnumDecl::treatAsExhaustiveForDiags(const DeclContext *useDC) const {
     if (enumModule->inSamePackage(useDC->getParentModule()))
       return true;
 
-    // If the module where enum is declared supports extensible enumerations
-    // and this enum is not explicitly marked as "@frozen", cross-module
-    // access cannot be exhaustive and requires `@unknown default:`.
-    if (enumModule->supportsExtensibleEnums() &&
-        !getAttrs().hasAttribute<FrozenAttr>()) {
-      if (useDC != enumModule->getDeclContext())
-        return false;
-    }
+    // When the enum is marked as `@nonexhaustive` cross-module access
+    // cannot be exhaustive and requires `@unknown default:`.
+    if (getAttrs().hasAttribute<NonexhaustiveAttr>() &&
+        enumModule != useDC->getParentModule())
+      return false;
   }
 
   return isFormallyExhaustive(useDC);
@@ -7142,8 +7388,7 @@ bool ProtocolDecl::existentialConformsToSelf() const {
 }
 
 bool ProtocolDecl::hasSelfOrAssociatedTypeRequirements() const {
-  // Because we will have considered all the protocols in a cyclic hierarchy by
-  // the time the cycle is hit.
+  // Be conservative and avoid diagnosing if we hit a cycle.
   const bool resultForCycle = false;
 
   return evaluateOrDefault(getASTContext().evaluator,
@@ -7193,8 +7438,7 @@ ArrayRef<ProtocolDecl *>
 ProtocolDecl::getProtocolDependencies() const {
   return evaluateOrDefault(
       getASTContext().evaluator,
-      ProtocolDependenciesRequest{const_cast<ProtocolDecl *>(this)},
-      std::nullopt);
+      ProtocolDependenciesRequest{const_cast<ProtocolDecl *>(this)}, {});
 }
 
 RequirementSignature ProtocolDecl::getRequirementSignature() const {
@@ -7202,7 +7446,7 @@ RequirementSignature ProtocolDecl::getRequirementSignature() const {
                RequirementSignatureRequest{const_cast<ProtocolDecl *>(this)},
                [this]() {
                  return RequirementSignature::getPlaceholderRequirementSignature(
-                     this, GenericSignatureErrors());
+                     this, GenericSignatureErrorFlags::CircularReference);
                });
 }
 
@@ -7362,6 +7606,10 @@ StringRef swift::getAccessorNameForDiagnostic(AccessorKind accessorKind,
     return "'didSet'";
   case AccessorKind::Init:
     return article ? "an init accessor" : "init accessor";
+  case AccessorKind::Borrow:
+    return article ? " a 'borrow' accessor" : "borrow accessor";
+  case AccessorKind::Mutate:
+    return article ? "a 'mutate' accessor" : "mutate accessor";
   }
   llvm_unreachable("bad accessor kind");
 }
@@ -7454,7 +7702,7 @@ void AbstractStorageDecl::setAccessors(SourceLoc lbraceLoc,
 // Compute the number of opaque accessors.
 const size_t NumOpaqueAccessors =
   0
-#define ACCESSOR(ID)
+#define ACCESSOR(ID, KEYWORD)
 #define OPAQUE_ACCESSOR(ID, KEYWORD) \
   + 1
 #include "swift/AST/AccessorKinds.def"
@@ -7477,14 +7725,14 @@ AbstractStorageDecl::AccessorRecord::create(ASTContext &ctx,
   // Make sure that we have enough space to add implicit opaque accessors later.
   size_t numMissingOpaque = NumOpaqueAccessors;
   {
-#define ACCESSOR(ID)
+#define ACCESSOR(ID, KEYWORD)
 #define OPAQUE_ACCESSOR(ID, KEYWORD)          \
     bool has##ID = false;
 #include "swift/AST/AccessorKinds.def"
     for (auto accessor : accessors) {
       switch (accessor->getAccessorKind()) {
-#define ACCESSOR(ID)                          \
-      case AccessorKind::ID:                  \
+#define ACCESSOR(ID, KEYWORD)                                                  \
+      case AccessorKind::ID:                                                   \
         continue;
 #define OPAQUE_ACCESSOR(ID, KEYWORD)          \
       case AccessorKind::ID:                  \
@@ -7951,50 +8199,6 @@ SourceRange AbstractStorageDecl::getTypeSourceRangeForDiagnostics() const {
   return SourceRange();
 }
 
-static std::optional<std::pair<CaseStmt *, Pattern *>>
-findParentPatternCaseStmtAndPattern(const VarDecl *inputVD) {
-  auto getMatchingPattern = [&](CaseStmt *cs) -> Pattern * {
-    // Check if inputVD is in our case body var decls if we have any. If we do,
-    // treat its pattern as our first case label item pattern.
-    for (auto *vd : cs->getCaseBodyVariablesOrEmptyArray()) {
-      if (vd == inputVD) {
-        return cs->getMutableCaseLabelItems().front().getPattern();
-      }
-    }
-
-    // Then check the rest of our case label items.
-    for (auto &item : cs->getMutableCaseLabelItems()) {
-      if (item.getPattern()->containsVarDecl(inputVD)) {
-        return item.getPattern();
-      }
-    }
-
-    // Otherwise return false if we do not find anything.
-    return nullptr;
-  };
-
-  // First find our canonical var decl. This is the VarDecl corresponding to the
-  // first case label item of the first case block in the fallthrough chain that
-  // our case block is within. Grab the case stmt associated with that var decl
-  // and start traveling down the fallthrough chain looking for the case
-  // statement that the input VD belongs to by using getMatchingPattern().
-  auto *canonicalVD = inputVD->getCanonicalVarDecl();
-  auto *caseStmt =
-      dyn_cast_or_null<CaseStmt>(canonicalVD->getParentPatternStmt());
-  if (!caseStmt)
-    return std::nullopt;
-
-  if (auto *p = getMatchingPattern(caseStmt))
-    return std::make_pair(caseStmt, p);
-
-  while ((caseStmt = caseStmt->getFallthroughDest().getPtrOrNull())) {
-    if (auto *p = getMatchingPattern(caseStmt))
-      return std::make_pair(caseStmt, p);
-  }
-
-  return std::nullopt;
-}
-
 VarDecl *VarDecl::getCanonicalVarDecl() const {
   // Any var decl without a parent var decl is canonical. This means that before
   // type checking, all var decls are canonical.
@@ -8019,16 +8223,7 @@ VarDecl *VarDecl::getCanonicalVarDecl() const {
 }
 
 Stmt *VarDecl::getRecursiveParentPatternStmt() const {
-  // If our parent is already a pattern stmt, just return that.
-  if (auto *stmt = getParentPatternStmt())
-    return stmt;
-
-  // Otherwise, see if we have a parent var decl. If we do not, then return
-  // nullptr. Otherwise, return the case stmt that we found.
-  auto result = findParentPatternCaseStmtAndPattern(this);
-  if (!result.has_value())
-    return nullptr;
-  return result->first;
+  return getCanonicalVarDecl()->getParentPatternStmt();
 }
 
 /// Return the Pattern involved in initializing this VarDecl.  Recall that the
@@ -8048,17 +8243,34 @@ Pattern *VarDecl::getParentPattern() const {
   }
 
   // If this is a statement parent, dig the pattern out of it.
-  if (auto *stmt = getParentPatternStmt()) {
+  const auto *canonicalVD = getCanonicalVarDecl();
+  if (auto *stmt = canonicalVD->getParentPatternStmt()) {
     if (auto *FES = dyn_cast<ForEachStmt>(stmt))
       return FES->getPattern();
 
     if (auto *cs = dyn_cast<CaseStmt>(stmt)) {
-      // In a case statement, search for the pattern that contains it.  This is
-      // a bit silly, because you can't have something like "case x, y:" anyway.
-      for (auto items : cs->getCaseLabelItems()) {
-        if (items.getPattern()->containsVarDecl(this))
-          return items.getPattern();
+      // In a case statement, search for the pattern that contains it.
+      auto findPattern = [](CaseStmt *cs, const VarDecl *VD) -> Pattern * {
+        for (auto items : cs->getCaseLabelItems()) {
+          if (items.getPattern()->containsVarDecl(VD))
+            return items.getPattern();
+        }
+        return nullptr;
+      };
+      if (auto *P = findPattern(cs, this))
+        return P;
+
+      // If it's not in the CaseStmt, check its fallthrough destination.
+      if (auto fallthrough = cs->getFallthroughDest()) {
+        if (auto *P = findPattern(fallthrough.get(), this))
+          return P;
       }
+
+      // Finally, check the canonical variable, this is necessary to correctly
+      // handle case body vars, we just want to take the first pattern that
+      // declares it in that case.
+      if (auto *P = findPattern(cs, canonicalVD))
+        return P;
     }
 
     if (auto *LCS = dyn_cast<LabeledConditionalStmt>(stmt)) {
@@ -8069,14 +8281,6 @@ Pattern *VarDecl::getParentPattern() const {
     }
   }
 
-  // Otherwise, check if we have to walk our case stmt's var decl list to find
-  // the pattern.
-  if (auto caseStmtPatternPair = findParentPatternCaseStmtAndPattern(this)) {
-    return caseStmtPatternPair->second;
-  }
-
-  // Otherwise, this is a case we do not know or understand. Return nullptr to
-  // signal we do not have any information.
   return nullptr;
 }
 
@@ -8137,7 +8341,7 @@ bool VarDecl::isCaseBodyVariable() const {
   auto *caseStmt = dyn_cast_or_null<CaseStmt>(getRecursiveParentPatternStmt());
   if (!caseStmt)
     return false;
-  return llvm::any_of(caseStmt->getCaseBodyVariablesOrEmptyArray(),
+  return llvm::any_of(caseStmt->getCaseBodyVariables(),
                       [&](VarDecl *vd) { return vd == this; });
 }
 
@@ -8363,7 +8567,7 @@ LifetimeAnnotation ParamDecl::getLifetimeAnnotation() const {
   auto specifier = getSpecifier();
   // Copyable parameters which are consumed have eager-move semantics.
   if (specifier == ParamDecl::Specifier::Consuming &&
-      !getTypeInContext()->isNoncopyable()) {
+      getTypeInContext()->isCopyable()) {
     if (getAttrs().hasAttribute<NoEagerMoveAttr>())
       return LifetimeAnnotation::Lexical;
     return LifetimeAnnotation::EagerMove;
@@ -8748,14 +8952,6 @@ void VarDecl::emitLetToVarNoteIfSimple(DeclContext *UseDC) const {
   }
 }
 
-std::optional<ExecutionKind>
-AbstractFunctionDecl::getExecutionBehavior() const {
-  auto *attr = getAttrs().getAttribute<ExecutionAttr>();
-  if (!attr)
-    return {};
-  return attr->getBehavior();
-}
-
 clang::PointerAuthQualifier VarDecl::getPointerAuthQualifier() const {
   if (auto *clangDecl = getClangDecl()) {
     if (auto *valueDecl = dyn_cast<clang::ValueDecl>(clangDecl)) {
@@ -8807,6 +9003,21 @@ ParamDecl *ParamDecl::clone(const ASTContext &Ctx, ParamDecl *PD) {
   return Clone;
 }
 
+ParamDecl *ParamDecl::cloneAccessor(const ASTContext &Ctx,
+                                    ParamDecl const *subscriptParam,
+                                    DeclContext *Parent) {
+  auto *param = new (Ctx) ParamDecl(
+      subscriptParam->getSpecifierLoc(), subscriptParam->getArgumentNameLoc(),
+      subscriptParam->getArgumentName(), subscriptParam->getNameLoc(),
+      subscriptParam->getName(), /*declContext*/ Parent);
+  param->setOptions(subscriptParam->getOptions());
+
+  // The cloned parameter is implicit.
+  param->setImplicit();
+
+  return param;
+}
+
 ParamDecl *
 ParamDecl::createImplicit(ASTContext &Context, SourceLoc specifierLoc,
                           SourceLoc argumentNameLoc, Identifier argumentName,
@@ -8940,6 +9151,12 @@ void ParamDecl::setTypeRepr(TypeRepr *repr) {
         continue;
       }
 
+      if (auto *callerIsolated =
+              dyn_cast<CallerIsolatedTypeRepr>(unwrappedType)) {
+        setCallerIsolated(true);
+        unwrappedType = callerIsolated->getBase();
+      }
+
       break;
     }
   }
@@ -9203,7 +9420,7 @@ void ParamDecl::setDefaultExpr(Expr *E) {
   auto *defaultInfo = DefaultValueAndFlags.getPointer();
   if (defaultInfo) {
     assert(defaultInfo->DefaultArg.isNull() ||
-           defaultInfo->DefaultArg.is<Expr *>());
+           isa<Expr *>(defaultInfo->DefaultArg));
 
     auto *const oldE = defaultInfo->DefaultArg.dyn_cast<Expr *>();
     assert((bool)E == (bool)oldE && "Overwrite of non-null default with null");
@@ -9222,7 +9439,18 @@ void ParamDecl::setDefaultExpr(Expr *E) {
 }
 
 void ParamDecl::setTypeCheckedDefaultExpr(Expr *E) {
-  assert(E || getDefaultArgumentKind() == DefaultArgumentKind::Inherited);
+  // The type-checker will only produce a null expression here if the
+  // default argument is inherited, so if we're called with a null pointer
+  // in any other case, it must be from a request cycle. Don't crash;
+  // just wrap the original expression with an ErrorExpr and proceed.
+  if (!E && getDefaultArgumentKind() != DefaultArgumentKind::Inherited) {
+    auto *initExpr = getStructuralDefaultExpr();
+    assert(initExpr);
+    auto &ctx = getASTContext();
+    E = new (ctx) ErrorExpr(initExpr->getSourceRange(), ErrorType::get(ctx),
+                            initExpr);
+  }
+
   setDefaultExpr(E);
 
   auto *defaultInfo = DefaultValueAndFlags.getPointer();
@@ -9258,7 +9486,7 @@ void ParamDecl::setStoredProperty(VarDecl *var) {
 
   auto *defaultInfo = DefaultValueAndFlags.getPointer();
   assert(defaultInfo->DefaultArg.isNull() ||
-         defaultInfo->DefaultArg.is<VarDecl *>());
+         isa<VarDecl *>(defaultInfo->DefaultArg));
   defaultInfo->DefaultArg = var;
 }
 
@@ -9674,6 +9902,8 @@ DeclName AbstractFunctionDecl::getEffectiveFullName() const {
     case AccessorKind::Read2:
     case AccessorKind::Modify:
     case AccessorKind::Modify2:
+    case AccessorKind::Borrow:
+    case AccessorKind::Mutate:
       return subscript ? subscript->getName()
                        : DeclName(ctx, storage->getBaseName(),
                                   ArrayRef<Identifier>());
@@ -9753,12 +9983,6 @@ Type AbstractFunctionDecl::getMethodInterfaceType() const {
   return Ty->castTo<AnyFunctionType>()->getResult();
 }
 
-bool AbstractFunctionDecl::hasDynamicSelfResult() const {
-  if (auto *funcDecl = dyn_cast<FuncDecl>(this))
-    return funcDecl->getResultInterfaceType()->hasDynamicSelfType();
-  return isa<ConstructorDecl>(this);
-}
-
 AbstractFunctionDecl *AbstractFunctionDecl::getAsyncAlternative() const {
   // Async functions can't have async alternatives
   if (hasAsync())
@@ -10190,30 +10414,20 @@ SourceRange AbstractFunctionDecl::getSignatureSourceRange() const {
   if (isImplicit())
     return SourceRange();
 
-  SourceLoc endLoc;
-
-  // name(parameter list...) async throws(E)
+  SourceRange thrownTypeRange;
   if (auto *typeRepr = getThrownTypeRepr())
-    endLoc = typeRepr->getSourceRange().End;
-  if (endLoc.isInvalid())
-    endLoc = getThrowsLoc();
-  if (endLoc.isInvalid())
-    endLoc = getAsyncLoc();
+    thrownTypeRange = typeRepr->getSourceRange();
 
-  if (endLoc.isInvalid())
-    return getParameterListSourceRange();
-  return SourceRange(getNameLoc(), endLoc);
+  // name(parameter list...) async throws(E)
+  return SourceRange::combine(getParameterListSourceRange(), getAsyncLoc(),
+                              getThrowsLoc(), thrownTypeRange);
 }
 
 SourceRange AbstractFunctionDecl::getParameterListSourceRange() const {
   if (isImplicit())
     return SourceRange();
 
-  auto endLoc = getParameters()->getSourceRange().End;
-  if (endLoc.isInvalid())
-    return getNameLoc();
-
-  return SourceRange(getNameLoc(), endLoc);
+  return SourceRange::combine(getNameLoc(), getParameters()->getSourceRange());
 }
 
 std::optional<Fingerprint> AbstractFunctionDecl::getBodyFingerprint() const {
@@ -10443,6 +10657,15 @@ bool AbstractFunctionDecl::isObjCInstanceMethod() const {
   return isInstanceMember() || isa<ConstructorDecl>(this);
 }
 
+std::optional<ForeignLanguage> AbstractFunctionDecl::getCDeclKind() const {
+  auto attr = getAttrs().getAttribute<CDeclAttr>();
+  if (!attr)
+    return std::nullopt;
+
+  return attr->Underscored ? ForeignLanguage::ObjectiveC
+                           : ForeignLanguage::C;
+}
+
 bool AbstractFunctionDecl::needsNewVTableEntry() const {
   auto &ctx = getASTContext();
   return evaluateOrDefault(
@@ -10502,7 +10725,7 @@ bool AbstractFunctionDecl::isValidKeyPathComponent() const {
 
 bool AbstractFunctionDecl::isResilient() const {
   // Check for attributes that makes functions non-resilient.
-  if (getAttrs().hasAttribute<InlinableAttr>() &&
+  if (hasAttributeWithInlinableSemantics() &&
       getAttrs().hasAttribute<UsableFromInlineAttr>())
     return false;
 
@@ -10551,9 +10774,8 @@ OpaqueTypeDecl::OpaqueTypeDecl(ValueDecl *NamingDecl,
   assert(OpaqueReturnTypeReprs.empty() ||
          OpaqueReturnTypeReprs.size() ==
             OpaqueInterfaceGenericSignature.getInnermostGenericParams().size());
-  std::uninitialized_copy(
-      OpaqueReturnTypeReprs.begin(), OpaqueReturnTypeReprs.end(),
-      getTrailingObjects<TypeRepr *>());
+  std::uninitialized_copy(OpaqueReturnTypeReprs.begin(),
+                          OpaqueReturnTypeReprs.end(), getTrailingObjects());
 }
 
 OpaqueTypeDecl *OpaqueTypeDecl::get(
@@ -10624,7 +10846,11 @@ bool OpaqueTypeDecl::exportUnderlyingType() const {
 }
 
 std::optional<SubstitutionMap>
-OpaqueTypeDecl::getUniqueUnderlyingTypeSubstitutions() const {
+OpaqueTypeDecl::getUniqueUnderlyingTypeSubstitutions(
+    bool typeCheckFunctionBodies) const {
+  if (!typeCheckFunctionBodies)
+    return UniqueUnderlyingType;
+
   return evaluateOrDefault(getASTContext().evaluator,
                            UniqueUnderlyingTypeSubstitutionsRequest{this}, {});
 }
@@ -10665,14 +10891,12 @@ void OpaqueTypeDecl::setConditionallyAvailableSubstitutions(
 
 OpaqueTypeDecl::ConditionallyAvailableSubstitutions *
 OpaqueTypeDecl::ConditionallyAvailableSubstitutions::get(
-    ASTContext &ctx,
-    ArrayRef<AvailabilityCondition> availabilityContext,
+    ASTContext &ctx, ArrayRef<AvailabilityQuery> availabilityQueries,
     SubstitutionMap substitutions) {
-  auto size =
-      totalSizeToAlloc<AvailabilityCondition>(availabilityContext.size());
+  auto size = totalSizeToAlloc<AvailabilityQuery>(availabilityQueries.size());
   auto mem = ctx.Allocate(size, alignof(ConditionallyAvailableSubstitutions));
   return new (mem)
-      ConditionallyAvailableSubstitutions(availabilityContext, substitutions);
+      ConditionallyAvailableSubstitutions(availabilityQueries, substitutions);
 }
 
 bool AbstractFunctionDecl::hasInlinableBodyText() const {
@@ -10957,7 +11181,7 @@ AccessorDecl *AccessorDecl::createImplicit(ASTContext &ctx,
       ctx, /*declLoc=*/SourceLoc(),
       /*accessorKeywordLoc=*/SourceLoc(), accessorKind,
       storage, async, /*asyncLoc=*/SourceLoc(),
-      /*throws=*/true, /*throwsLoc=*/SourceLoc(),
+      /*throws=*/throws, /*throwsLoc=*/SourceLoc(),
       thrownType, parent,
       /*clangNode=*/ClangNode());
   D->setImplicit();
@@ -11011,20 +11235,7 @@ AccessorDecl *AccessorDecl::createParsed(
       paramsEnd = indices->getEndLoc();
     }
     for (auto *subscriptParam : *indices) {
-      // Clone the parameter.
-      auto *param = new (ctx) ParamDecl(
-          subscriptParam->getSpecifierLoc(),
-          subscriptParam->getArgumentNameLoc(),
-          subscriptParam->getArgumentName(), subscriptParam->getNameLoc(),
-          subscriptParam->getName(), /*declContext*/ accessor);
-      param->setAutoClosure(subscriptParam->isAutoClosure());
-
-      // The cloned parameter is implicit.
-      param->setImplicit();
-
-      if (subscriptParam->isSending())
-        param->setSending();
-
+      auto param = ParamDecl::cloneAccessor(ctx, subscriptParam, accessor);
       newParams.push_back(param);
     }
 
@@ -11052,6 +11263,8 @@ StringRef AccessorDecl::implicitParameterNameFor(AccessorKind kind) {
   case AccessorKind::Modify2:
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
     return StringRef();
   }
 }
@@ -11063,6 +11276,7 @@ bool AccessorDecl::isAssumedNonMutating() const {
   case AccessorKind::Address:
   case AccessorKind::Read:
   case AccessorKind::Read2:
+  case AccessorKind::Borrow:
     return true;
 
   case AccessorKind::Set:
@@ -11072,6 +11286,7 @@ bool AccessorDecl::isAssumedNonMutating() const {
   case AccessorKind::Modify:
   case AccessorKind::Modify2:
   case AccessorKind::Init:
+  case AccessorKind::Mutate:
     return false;
   }
   llvm_unreachable("bad accessor kind");
@@ -11220,7 +11435,7 @@ LifetimeAnnotation FuncDecl::getLifetimeAnnotation() const {
   // Copyable parameters which are consumed have eager-move semantics.
   if (getSelfAccessKind() == SelfAccessKind::Consuming) {
     auto *selfDecl = getImplicitSelfDecl();
-    if (selfDecl && !selfDecl->getTypeInContext()->isNoncopyable()) {
+    if (selfDecl && selfDecl->getTypeInContext()->isCopyable()) {
       if (getAttrs().hasAttribute<NoEagerMoveAttr>())
         return LifetimeAnnotation::Lexical;
       return LifetimeAnnotation::EagerMove;
@@ -11324,33 +11539,62 @@ DestructorDecl *DestructorDecl::getSuperDeinit() const {
   return nullptr;
 }
 
-SourceRange FuncDecl::getSourceRange() const {
-  SourceLoc startLoc = getStartLoc();
+SourceLoc FuncDecl::getStartLoc() const {
+  if (StaticLoc)
+    return StaticLoc;
 
-  if (startLoc.isInvalid())
-    return SourceRange();
+  if (FuncLoc)
+    return FuncLoc;
 
-  if (getBodyKind() == BodyKind::Unparsed)
-    return { startLoc, BodyRange.End };
+  auto nameLoc = getNameLoc();
+  if (nameLoc)
+    return nameLoc;
 
-  SourceLoc endLoc = getOriginalBodySourceRange().End;
-  if (endLoc.isInvalid()) {
-    if (isa<AccessorDecl>(this))
-      return startLoc;
+  auto sigStart = getSignatureSourceRange().Start;
+  if (sigStart)
+    return sigStart;
 
-    if (getBodyKind() == BodyKind::Synthesize)
-      return SourceRange();
+  auto resultTyStart = getResultTypeSourceRange().Start;
+  if (resultTyStart)
+    return resultTyStart;
 
-    endLoc = getGenericTrailingWhereClauseSourceRange().End;
-  }
-  if (endLoc.isInvalid())
-    endLoc = getResultTypeSourceRange().End;
-  if (endLoc.isInvalid())
-    endLoc = getSignatureSourceRange().End;
-  if (endLoc.isInvalid())
-    endLoc = startLoc;
+  auto genericWhereStart = getGenericTrailingWhereClauseSourceRange().Start;
+  if (genericWhereStart)
+    return genericWhereStart;
 
-  return { startLoc, endLoc };
+  auto bodyStart = getOriginalBodySourceRange().Start;
+  if (bodyStart)
+    return bodyStart;
+
+  return SourceLoc();
+}
+
+SourceLoc FuncDecl::getEndLoc() const {
+  auto bodyEnd = getOriginalBodySourceRange().End;
+  if (bodyEnd)
+    return bodyEnd;
+
+  auto genericWhereEnd = getGenericTrailingWhereClauseSourceRange().End;
+  if (genericWhereEnd)
+    return genericWhereEnd;
+
+  auto resultTyEnd = getResultTypeSourceRange().End;
+  if (resultTyEnd)
+    return resultTyEnd;
+
+  auto sigEnd = getSignatureSourceRange().End;
+  if (sigEnd)
+    return sigEnd;
+
+  return getStartLoc();
+}
+
+SourceRange FuncDecl::getSourceRange() const {
+  SourceLoc startLoc = getStartLoc();
+  if (startLoc.isInvalid())
+    return SourceRange();
+
+  return { startLoc, getEndLoc() };
 }
 
 EnumElementDecl::EnumElementDecl(SourceLoc IdentifierLoc, DeclName Name,
@@ -11630,6 +11874,12 @@ PrecedenceGroupDecl *InfixOperatorDecl::getPrecedenceGroup() const {
       nullptr);
 }
 
+bool ValueDecl::isDeferBody() const {
+  if (auto fn = dyn_cast<FuncDecl>(this))
+    return fn->isDeferBody();
+  return false;
+}
+
 bool FuncDecl::isDeferBody() const {
   return getBaseIdentifier() == getASTContext().getIdentifier("$defer");
 }
@@ -11821,55 +12071,93 @@ ActorIsolation swift::getActorIsolationOfContext(
     DeclContext *dc,
     llvm::function_ref<ActorIsolation(AbstractClosureExpr *)>
         getClosureActorIsolation) {
-  auto &ctx = dc->getASTContext();
   auto dcToUse = dc;
-  // Defer bodies share actor isolation of their enclosing context.
-  if (auto FD = dyn_cast<FuncDecl>(dcToUse)) {
-    if (FD->isDeferBody()) {
-      dcToUse = FD->getDeclContext();
-    }
+
+  // Defer bodies share the actor isolation of their enclosing context.
+  // We don't actually have to do this check here because
+  // getActorIsolation does consider it already, but it's nice to
+  // avoid some extra request evaluation in a trivial case.
+  while (auto FD = dyn_cast<FuncDecl>(dcToUse)) {
+    if (!FD->isDeferBody()) break;
+    dcToUse = FD->getDeclContext();
   }
+
   if (auto *vd = dyn_cast_or_null<ValueDecl>(dcToUse->getAsDecl()))
     return getActorIsolation(vd);
 
-  // In the context of the initializing or default-value expression of a
-  // stored property:
-  //   - For a static stored property, the isolation matches the VarDecl.
-  //     Static properties are initialized upon first use, so the isolation
-  //     of the initializer must match the isolation required to access the
-  //     property.
-  //   - For a field of a nominal type, the expression can require the same
-  //     actor isolation as the field itself. That default expression may only
-  //     be used from inits that meet the required isolation.
-  if (auto *var = dcToUse->getNonLocalVarDecl()) {
-    // If IsolatedDefaultValues are enabled, treat this context as having
-    // unspecified isolation. We'll compute the required isolation for
-    // the initializer and validate that it matches the isolation of the
-    // var itself in the DefaultInitializerIsolation request.
-    if (ctx.LangOpts.hasFeature(Feature::IsolatedDefaultValues))
-      return ActorIsolation::forUnspecified();
-
-    return getActorIsolation(var);
-  }
-
   if (auto *closure = dyn_cast<AbstractClosureExpr>(dcToUse)) {
     return getClosureActorIsolation(closure);
   }
 
+  if (auto *init = dyn_cast<Initializer>(dcToUse)) {
+    // FIXME: force default argument initializers to report a meaningless
+    // isolation in order to break a bunch of cycles with the way that
+    // isolation is computed for them.
+    return getActorIsolation(init, /*ignoreDefaultArguments*/ true);
+  }
+
   if (isa<TopLevelCodeDecl>(dcToUse)) {
+    auto &ctx = dc->getASTContext();
     if (dcToUse->isAsyncContext() ||
-        dcToUse->getASTContext().LangOpts.StrictConcurrencyLevel >=
-            StrictConcurrency::Complete) {
-      if (Type mainActor = dcToUse->getASTContext().getMainActorType())
+        ctx.LangOpts.StrictConcurrencyLevel >= StrictConcurrency::Complete) {
+      if (Type mainActor = ctx.getMainActorType())
         return ActorIsolation::forGlobalActor(mainActor)
-            .withPreconcurrency(
-                !dcToUse->getASTContext().isSwiftVersionAtLeast(6));
+            .withPreconcurrency(!ctx.isSwiftVersionAtLeast(6));
     }
   }
 
   return ActorIsolation::forUnspecified();
 }
 
+ActorIsolation swift::getActorIsolation(Initializer *init,
+                                        bool ignoreDefaultArguments) {
+  switch (init->getInitializerKind()) {
+  case InitializerKind::PatternBinding:
+    // In the context of the initializing or default-value expression of a
+    // stored property:
+    //   - For a static stored property, the isolation matches the VarDecl.
+    //     Static properties are initialized upon first use, so the isolation
+    //     of the initializer must match the isolation required to access the
+    //     property.
+    //   - For a field of a nominal type, the expression can require the same
+    //     actor isolation as the field itself. That default expression may only
+    //     be used from inits that meet the required isolation.
+    if (auto *var = init->getNonLocalVarDecl()) {
+      auto &ctx = var->getASTContext();
+
+      // If IsolatedDefaultValues are enabled, treat this context as having
+      // unspecified isolation. We'll compute the required isolation for
+      // the initializer and validate that it matches the isolation of the
+      // var itself in the DefaultInitializerIsolation request.
+      if (ctx.LangOpts.hasFeature(Feature::IsolatedDefaultValues))
+        return ActorIsolation::forUnspecified();
+
+      return getActorIsolation(var);
+    }
+
+    return ActorIsolation::forUnspecified();
+
+  case InitializerKind::DefaultArgument: {
+    auto defArgInit = cast<DefaultArgumentInitializer>(init);
+
+    // A hack when used from getActorIsolationOfContext to maintain the
+    // current behavior and avoid request cycles.
+    if (ignoreDefaultArguments)
+      return ActorIsolation::forUnspecified();
+
+    auto fn = cast<ValueDecl>(defArgInit->getParent()->getAsDecl());
+    auto param = getParameterAt(fn, defArgInit->getIndex());
+    assert(param);
+    return param->getInitializerIsolation();
+  }
+
+  case InitializerKind::PropertyWrapper:
+  case InitializerKind::CustomAttribute:
+    return ActorIsolation::forUnspecified();
+  }
+  llvm_unreachable("bad initializer kind");
+}
+
 bool swift::isSameActorIsolated(ValueDecl *value, DeclContext *dc) {
     auto valueIsolation = getActorIsolation(value);
     auto dcIsolation = getActorIsolationOfContext(dc);
@@ -11945,7 +12233,7 @@ Decl *TypeOrExtensionDecl::getAsDecl() const {
   if (auto NTD = Decl.dyn_cast<NominalTypeDecl *>())
     return NTD;
 
-  return Decl.get<ExtensionDecl *>();
+  return cast<ExtensionDecl *>(Decl);
 }
 DeclContext *TypeOrExtensionDecl::getAsDeclContext() const {
   return getAsDecl()->getInnermostDeclContext();
@@ -11955,7 +12243,7 @@ IterableDeclContext *TypeOrExtensionDecl::getAsIterableDeclContext() const {
   if (auto nominal = Decl.dyn_cast<NominalTypeDecl *>())
     return nominal;
 
-  return Decl.get<ExtensionDecl *>();
+  return cast<ExtensionDecl *>(Decl);
 }
 
 NominalTypeDecl *TypeOrExtensionDecl::getBaseNominal() const {
@@ -12017,10 +12305,10 @@ StringRef swift::getAccessorLabel(AccessorKind kind) {
   switch (kind) {
   #define SINGLETON_ACCESSOR(ID, KEYWORD) \
     case AccessorKind::ID: return #KEYWORD;
-  #define ACCESSOR(ID)
-  #include "swift/AST/AccessorKinds.def"
-    }
-    llvm_unreachable("bad accessor kind");
+#define ACCESSOR(ID, KEYWORD)
+#include "swift/AST/AccessorKinds.def"
+  }
+  llvm_unreachable("bad accessor kind");
 }
 
 void swift::simple_display(llvm::raw_ostream &out, AccessorKind kind) {
@@ -12600,10 +12888,10 @@ void MacroExpansionDecl::forEachExpandedNode(
     // expressions, declaration macros can only produce declarations,
     // and code item macros can produce expressions, declarations, and
     // statements.
-    if (roles.contains(MacroRole::Expression) && !node.is<Expr *>())
+    if (roles.contains(MacroRole::Expression) && !isa<Expr *>(node))
       continue;
 
-    if (roles.contains(MacroRole::Declaration) && !node.is<Decl *>())
+    if (roles.contains(MacroRole::Declaration) && !isa<Decl *>(node))
       continue;
 
     callback(node);
@@ -12682,7 +12970,7 @@ MacroDiscriminatorContext MacroDiscriminatorContext::getParentOf(
       if (!origDC->isChildContextOf(expansion->getDeclContext()))
         return MacroDiscriminatorContext(expansion);
     } else {
-      auto expansionDecl = cast<MacroExpansionDecl>(node.get<Decl *>());
+      auto expansionDecl = cast<MacroExpansionDecl>(cast<Decl *>(node));
       if (!origDC->isChildContextOf(expansionDecl->getDeclContext()))
         return MacroDiscriminatorContext(expansionDecl);
     }
@@ -12744,7 +13032,7 @@ CatchNode::getThrownErrorTypeInContext(ASTContext &ctx) const {
     return ctx.getErrorExistentialType();
   }
 
-  auto tryExpr = get<AnyTryExpr *>();
+  auto tryExpr = cast<AnyTryExpr *>(*this);
   if (auto forceTry = llvm::dyn_cast<ForceTryExpr>(tryExpr)) {
     if (auto thrownError = forceTry->getThrownError())
       return thrownError;
@@ -12797,7 +13085,7 @@ bool ExplicitCaughtTypeRequest::isCached() const {
   auto catchNode = std::get<1>(getStorage());
 
   // try? and try! never need to be cached.
-  if (catchNode.is<AnyTryExpr *>())
+  if (isa<AnyTryExpr *>(catchNode))
     return false;
 
   // Functions with explicitly-written thrown types need the result cached.
diff --git a/lib/AST/DeclContext.cpp b/lib/AST/DeclContext.cpp
index 7b5ea4cc21dfa..86890830c50d3 100644
--- a/lib/AST/DeclContext.cpp
+++ b/lib/AST/DeclContext.cpp
@@ -14,7 +14,8 @@
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/AccessScope.h"
-#include "swift/AST/AvailabilityInference.h"
+#include "swift/AST/AvailabilityConstraint.h"
+#include "swift/AST/AvailabilityContext.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/Expr.h"
@@ -213,8 +214,10 @@ AccessorDecl *DeclContext::getInnermostPropertyAccessorContext() {
         return nullptr;
 
       auto *storage = accessor->getStorage();
-      if (isa<VarDecl>(storage) && storage->getDeclContext()->isTypeContext())
+      if ((isa<VarDecl>(storage) || isa<SubscriptDecl>(storage)) &&
+          storage->getDeclContext()->isTypeContext()) {
         return accessor;
+      }
     }
   } while ((dc = dc->getParent()));
 
@@ -446,6 +449,16 @@ DeclContext *DeclContext::getModuleScopeContext() const {
 
 void DeclContext::getSeparatelyImportedOverlays(
     ModuleDecl *declaring, SmallVectorImpl<ModuleDecl *> &overlays) const {
+  if (declaring->isStdlibModule()) {
+    auto &ctx = getASTContext();
+    for (auto overlayName: ctx.StdlibOverlayNames) {
+      if (auto module = ctx.getLoadedModule(overlayName))
+        overlays.push_back(module);
+    }
+    overlays.push_back(declaring);
+    return;
+  }
+
   if (auto SF = getOutermostParentSourceFile())
     SF->getSeparatelyImportedOverlays(declaring, overlays);
 }
@@ -553,7 +566,7 @@ swift::FragileFunctionKindRequest::evaluate(Evaluator &evaluator,
         return {FragileFunctionKind::Transparent};
       }
 
-      if (AFD->getAttrs().hasAttribute<InlinableAttr>()) {
+      if (AFD->hasAttributeWithInlinableSemantics()) {
         return {FragileFunctionKind::Inlinable};
       }
 
@@ -561,7 +574,7 @@ swift::FragileFunctionKindRequest::evaluate(Evaluator &evaluator,
         return {FragileFunctionKind::AlwaysEmitIntoClient};
       }
 
-      if (AFD->isBackDeployed(context->getASTContext())) {
+      if (AFD->isBackDeployed()) {
         return {FragileFunctionKind::BackDeploy};
       }
 
@@ -569,13 +582,13 @@ swift::FragileFunctionKindRequest::evaluate(Evaluator &evaluator,
       // @backDeployed, and @inlinable from their storage declarations.
       if (auto accessor = dyn_cast<AccessorDecl>(AFD)) {
         auto *storage = accessor->getStorage();
-        if (storage->getAttrs().getAttribute<InlinableAttr>()) {
+        if (storage->hasAttributeWithInlinableSemantics()) {
           return {FragileFunctionKind::Inlinable};
         }
         if (storage->getAttrs().hasAttribute<AlwaysEmitIntoClientAttr>()) {
           return {FragileFunctionKind::AlwaysEmitIntoClient};
         }
-        if (storage->isBackDeployed(context->getASTContext())) {
+        if (storage->isBackDeployed()) {
           return {FragileFunctionKind::BackDeploy};
         }
       }
@@ -1496,14 +1509,32 @@ bool AccessScope::allowsPrivateAccess(const DeclContext *useDC, const DeclContex
     auto clangDecl = sourceNTD->getDecl()->getClangDecl();
 
     if (isa_and_nonnull<clang::EnumDecl>(clangDecl)) {
-      // Consider:  class C { private: enum class E { M }; };
-      // If sourceDC is a C++ enum (e.g, E), then we are looking at one of its
-      // members (e.g., E.M). If this is the case, then we should consider
-      // the SWIFT_PRIVATE_FILEID of its enclosing class decl (e.g., C), if any.
-      // Doing so allows the nested private enum's members to inherit the access
-      // of the nested enum type itself.
-      clangDecl = dyn_cast<clang::CXXRecordDecl>(clangDecl->getDeclContext());
-      sourceDC = sourceNTD->getDeclContext();
+      // C/C++ enums are an odd case for access checking because they can only
+      // contain variants as members, and those variants cannot be assigned
+      // access specifiers. Instead, those variants should simply inherit the
+      // access of their parent enum, if any. For instance:
+      //
+      //   class Base { protected: enum class E { M }; };
+      //   class Derived : public Base {};
+      //
+      // In C++, E::M should be accessible within Base and Derived; we should
+      // follow suit in Swift.
+      //
+      // When we check the access of something like E.M, clangDecl will point to
+      // enum class E (the DeclContext of M), and if we've gotten this far, we
+      // can infer that E was accessible in useDC, so its members should be too.
+      //
+      // This is technically unsound (i.e., encapsulation-breaking), because it
+      // is possible to extend imported Clang enums private in Swift extensions.
+      // With this hack, those private members would be accessible everywhere
+      // even though they shouldn't. But right here, when we're checking the E
+      // of E.M, there's no way to tell whether the M is something we imported
+      // from Clang (which we should allow) versus something we defined in Swift
+      // (which we should disallow), without over-complicating the access check.
+      // To limit the encapsulate the breakage, we do an additional check to
+      // ensure we're checking an imported enum that is *nested* in a Clang
+      // record (which is the only way this enum can be imported as private).
+      return isa_and_nonnull<clang::CXXRecordDecl>(clangDecl->getDeclContext());
     }
 
     if (!isa_and_nonnull<clang::CXXRecordDecl>(clangDecl))
@@ -1750,16 +1781,10 @@ bool DeclContext::isAlwaysAvailableConformanceContext() const {
   if (ext == nullptr)
     return true;
 
-  if (ext->isUnavailable())
-    return false;
-
+  // Check whether the extension is always available relative to the deployment
+  // target.
   auto &ctx = getASTContext();
-
-  // FIXME: [availability] Query AvailabilityContext, not platform range.
-  AvailabilityRange conformanceAvailability{
-      AvailabilityInference::availableRange(ext)};
-
-  auto deploymentTarget = AvailabilityRange::forDeploymentTarget(ctx);
-
-  return deploymentTarget.isContainedIn(conformanceAvailability);
+  auto deploymentTarget = AvailabilityContext::forDeploymentTarget(ctx);
+  auto constraints = getAvailabilityConstraintsForDecl(ext, deploymentTarget);
+  return !constraints.getPrimaryConstraint();
 }
diff --git a/lib/AST/DeclNameExtractor.cpp b/lib/AST/DeclNameExtractor.cpp
new file mode 100644
index 0000000000000..f76ae768c32b3
--- /dev/null
+++ b/lib/AST/DeclNameExtractor.cpp
@@ -0,0 +1,237 @@
+//===--- DeclNameExtractor.cpp --------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the DeclNameExtractor utility.
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/AST/DeclNameExtractor.h"
+#include "swift/AST/ASTContext.h"
+
+using namespace swift;
+using namespace Demangle;
+
+bool DeclNameExtractor::extractDeclName(Node *node, DeclName &name,
+                                        Identifier &privateDiscriminator) {
+  if (!node)
+    return false;
+
+  switch (node->getKind()) {
+  case Node::Kind::Class:
+  case Node::Kind::Structure:
+  case Node::Kind::Enum:
+  case Node::Kind::Protocol:
+  case Node::Kind::TypeAlias:
+  case Node::Kind::OtherNominalType:
+  case Node::Kind::AssociatedType:
+  case Node::Kind::AssociatedTypeRef:
+  case Node::Kind::GenericTypeParamDecl:
+  case Node::Kind::Variable:
+  case Node::Kind::Macro:
+    return extractIdentifierName(node, name, privateDiscriminator);
+
+  case Node::Kind::Constructor:
+  case Node::Kind::Allocator:
+    name = DeclName(DeclBaseName::createConstructor());
+    return true;
+
+  case Node::Kind::Destructor:
+  case Node::Kind::Deallocator:
+  case Node::Kind::IsolatedDeallocator:
+    name = DeclName(DeclBaseName::createDestructor());
+    return true;
+
+  case Node::Kind::Function:
+  case Node::Kind::Subscript:
+    return extractFunctionLikeName(node, name, privateDiscriminator);
+
+  default:
+    // For any other node types, we can't extract a meaningful name
+    return false;
+  }
+}
+
+bool DeclNameExtractor::extractIdentifierName(
+    Node *node, DeclName &declName, Identifier &privateDiscriminator) {
+  auto Identifier = node->getChild(1);
+  if (!Identifier)
+    return false;
+
+  StringRef name;
+  StringRef relatedEntityKind;
+  if (!extractNameNodeInfo(Ctx, Identifier, name, relatedEntityKind,
+                           privateDiscriminator)) {
+    return false;
+  }
+
+  declName = getIdentifier(Ctx, name);
+
+  return true;
+}
+
+bool DeclNameExtractor::extractFunctionLikeName(
+    Node *node, DeclName &declName, Identifier &privateDiscriminator) {
+  assert(node->getKind() == Node::Kind::Function ||
+         node->getKind() == Node::Kind::Subscript);
+
+  DeclBaseName BaseName;
+  if (node->getKind() == Node::Kind::Function) {
+    DeclName name;
+    if (extractIdentifierName(node, name, privateDiscriminator)) {
+      BaseName = name.getBaseName();
+    } else {
+      BaseName = extractOperatorName(node);
+    }
+  } else {
+    BaseName = DeclBaseName::createSubscript();
+  }
+
+  if (BaseName.empty())
+    return false;
+
+  // Location of LabelList node if present, otherwise a Type node.
+  unsigned LabelListIdx;
+  if (node->getKind() == Node::Kind::Function) {
+    LabelListIdx = 2;
+  } else {
+    LabelListIdx = 1;
+  }
+
+  auto *LabelsOrType = node->getChild(LabelListIdx);
+  assert(LabelsOrType != nullptr &&
+         (LabelsOrType->getKind() == Node::Kind::LabelList ||
+          LabelsOrType->getKind() == Node::Kind::Type));
+
+  SmallVector<Identifier, 4> ArgLabels;
+  if (LabelsOrType->getKind() == Node::Kind::LabelList) {
+    extractArgLabelsFromLabelList(LabelsOrType, ArgLabels);
+  } else {
+    extractArgLabelsFromType(LabelsOrType, ArgLabels);
+  }
+
+  if (ArgLabels.empty()) {
+    declName = DeclName(BaseName);
+    return true;
+  }
+
+  declName = DeclName(Ctx, BaseName, ArgLabels);
+  return true;
+}
+
+void DeclNameExtractor::extractArgLabelsFromLabelList(
+    Node *LabelList, SmallVectorImpl<Identifier> &ArgLabels) {
+  assert(LabelList->getKind() == Node::Kind::LabelList);
+
+  for (unsigned i = 0; i < LabelList->getNumChildren(); ++i) {
+    auto *Label = LabelList->getChild(i);
+
+    assert(Label && (Label->getKind() == Node::Kind::Identifier ||
+                     Label->getKind() == Node::Kind::FirstElementMarker));
+
+    if (Label->getKind() == Node::Kind::Identifier) {
+      ArgLabels.push_back(getIdentifier(Ctx, Label->getText()));
+    } else {
+      ArgLabels.push_back(Identifier());
+    }
+  }
+}
+
+void DeclNameExtractor::extractArgLabelsFromType(
+    Node *Type, SmallVectorImpl<Identifier> &ArgLabels) {
+  auto ArgTuple = Type->findByKind(Demangle::Node::Kind::ArgumentTuple,
+                                   /*maxDepth=*/5);
+  if (ArgTuple == nullptr)
+    return;
+
+  auto Params = ArgTuple->getFirstChild();
+  auto ParamsType = Params->getFirstChild();
+  if (ParamsType == nullptr)
+    return;
+
+  if (ParamsType->getKind() != Demangle::Node::Kind::Tuple) {
+    // A single, unnamed parameter
+    ArgLabels.push_back(Identifier());
+    return;
+  }
+
+  // More than one parameter are present
+  for (size_t i = 0; i < ParamsType->getNumChildren(); ++i) {
+    assert(ParamsType->getChild(i)->getKind() == Node::Kind::TupleElement &&
+           "Expected a TupleElement");
+    ArgLabels.push_back(Identifier());
+  }
+}
+
+DeclBaseName DeclNameExtractor::extractOperatorName(Node *node) {
+  auto Operator = node->getChild(1);
+  if (!Operator)
+    return DeclBaseName();
+
+  switch (Operator->getKind()) {
+  case Node::Kind::InfixOperator:
+  case Node::Kind::PrefixOperator:
+  case Node::Kind::PostfixOperator:
+    return getIdentifier(Ctx, Operator->getText());
+
+  default:
+    return DeclBaseName();
+  }
+}
+
+Identifier swift::Demangle::getIdentifier(ASTContext &Ctx, StringRef name) {
+  if (name.size() > 1 && name.front() == '`' && name.back() == '`') {
+    // Raw identifiers have backticks affixed before mangling. We need to
+    // remove those before creating the Identifier for the AST, which doesn't
+    // encode the backticks.
+    std::string fixedName;
+    for (size_t i = 1; i < name.size() - 1; ++i) {
+      unsigned char ch = name[i];
+      // Raw identifiers have the space (U+0020) replaced with a non-breaking
+      // space (U+00A0, UTF-8: 0xC2 0xA0) in their mangling so that parts of
+      // the runtime that use space as a delimiter remain compatible with
+      // these identifiers. Flip it back.
+      if (ch == 0xc2 && i < name.size() - 2 &&
+          (unsigned char)name[i + 1] == 0xa0) {
+        fixedName.push_back(' ');
+        ++i;
+      } else {
+        fixedName.push_back(ch);
+      }
+    }
+    return Ctx.getIdentifier(fixedName);
+  }
+  return Ctx.getIdentifier(name);
+}
+
+bool swift::Demangle::extractNameNodeInfo(ASTContext &Ctx, Node *node,
+                                          StringRef &name,
+                                          StringRef &relatedEntityKind,
+                                          Identifier &privateDiscriminator) {
+  switch (node->getKind()) {
+  case Demangle::Node::Kind::Identifier:
+    name = node->getText();
+    return true;
+
+  case Demangle::Node::Kind::PrivateDeclName:
+    name = node->getChild(1)->getText();
+    privateDiscriminator = getIdentifier(Ctx, node->getChild(0)->getText());
+    return true;
+
+  case Demangle::Node::Kind::RelatedEntityDeclName:
+    name = node->getChild(1)->getText();
+    relatedEntityKind = node->getFirstChild()->getText();
+    return true;
+
+  default:
+    return false;
+  }
+}
diff --git a/lib/AST/DiagnosticArgument.cpp b/lib/AST/DiagnosticArgument.cpp
new file mode 100644
index 0000000000000..18d4b8dc5a3b3
--- /dev/null
+++ b/lib/AST/DiagnosticArgument.cpp
@@ -0,0 +1,261 @@
+//===--- DiagnosticArgument.cpp ---------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/AST/DiagnosticArgument.h"
+#include "swift/Basic/Assertions.h"
+
+using namespace swift;
+
+DiagnosticArgument::DiagnosticArgument(StringRef S)
+    : Kind(DiagnosticArgumentKind::String), StringVal(S) {}
+
+DiagnosticArgument::DiagnosticArgument(int I)
+    : Kind(DiagnosticArgumentKind::Integer), IntegerVal(I) {}
+
+DiagnosticArgument::DiagnosticArgument(unsigned I)
+    : Kind(DiagnosticArgumentKind::Unsigned), UnsignedVal(I) {}
+
+DiagnosticArgument::DiagnosticArgument(DeclNameRef R)
+    : Kind(DiagnosticArgumentKind::Identifier), IdentifierVal(R) {}
+
+DiagnosticArgument::DiagnosticArgument(DeclName D)
+    : Kind(DiagnosticArgumentKind::Identifier), IdentifierVal(DeclNameRef(D)) {}
+
+DiagnosticArgument::DiagnosticArgument(DeclBaseName D)
+    : Kind(DiagnosticArgumentKind::Identifier), IdentifierVal(DeclNameRef(D)) {}
+
+DiagnosticArgument::DiagnosticArgument(Identifier I)
+    : Kind(DiagnosticArgumentKind::Identifier), IdentifierVal(DeclNameRef(I)) {}
+
+DiagnosticArgument::DiagnosticArgument(ObjCSelector S)
+    : Kind(DiagnosticArgumentKind::ObjCSelector), ObjCSelectorVal(S) {}
+
+DiagnosticArgument::DiagnosticArgument(const Decl *VD)
+    : Kind(DiagnosticArgumentKind::Decl), TheDecl(VD) {}
+
+DiagnosticArgument::DiagnosticArgument(Type T)
+    : Kind(DiagnosticArgumentKind::Type), TypeVal(T) {}
+
+DiagnosticArgument::DiagnosticArgument(TypeRepr *T)
+    : Kind(DiagnosticArgumentKind::TypeRepr), TyR(T) {}
+
+DiagnosticArgument::DiagnosticArgument(FullyQualified<Type> FQT)
+    : Kind(DiagnosticArgumentKind::FullyQualifiedType),
+      FullyQualifiedTypeVal(FQT) {}
+
+DiagnosticArgument::DiagnosticArgument(WitnessType WT)
+    : Kind(DiagnosticArgumentKind::WitnessType), WitnessTypeVal(WT) {}
+
+DiagnosticArgument::DiagnosticArgument(const TypeLoc &TL) {
+  if (TypeRepr *tyR = TL.getTypeRepr()) {
+    Kind = DiagnosticArgumentKind::TypeRepr;
+    TyR = tyR;
+  } else {
+    Kind = DiagnosticArgumentKind::Type;
+    TypeVal = TL.getType();
+  }
+}
+
+DiagnosticArgument::DiagnosticArgument(DescriptivePatternKind DPK)
+    : Kind(DiagnosticArgumentKind::DescriptivePatternKind),
+      DescriptivePatternKindVal(DPK) {}
+
+DiagnosticArgument::DiagnosticArgument(ReferenceOwnership RO)
+    : Kind(DiagnosticArgumentKind::ReferenceOwnership),
+      ReferenceOwnershipVal(RO) {}
+
+DiagnosticArgument::DiagnosticArgument(SelfAccessKind SAK)
+    : Kind(DiagnosticArgumentKind::SelfAccessKind), SelfAccessKindVal(SAK) {}
+
+DiagnosticArgument::DiagnosticArgument(StaticSpellingKind SSK)
+    : Kind(DiagnosticArgumentKind::StaticSpellingKind),
+      StaticSpellingKindVal(SSK) {}
+
+DiagnosticArgument::DiagnosticArgument(DescriptiveDeclKind DDK)
+    : Kind(DiagnosticArgumentKind::DescriptiveDeclKind),
+      DescriptiveDeclKindVal(DDK) {}
+
+DiagnosticArgument::DiagnosticArgument(StmtKind SK)
+    : Kind(DiagnosticArgumentKind::DescriptiveStmtKind),
+      DescriptiveStmtKindVal(SK) {}
+
+DiagnosticArgument::DiagnosticArgument(const DeclAttribute *attr)
+    : Kind(DiagnosticArgumentKind::DeclAttribute), DeclAttributeVal(attr) {}
+
+DiagnosticArgument::DiagnosticArgument(const TypeAttribute *attr)
+    : Kind(DiagnosticArgumentKind::TypeAttribute), TypeAttributeVal(attr) {}
+
+DiagnosticArgument::DiagnosticArgument(const AvailabilityDomain domain)
+    : Kind(DiagnosticArgumentKind::AvailabilityDomain),
+      AvailabilityDomainVal(domain) {}
+
+DiagnosticArgument::DiagnosticArgument(const AvailabilityRange &range)
+    : Kind(DiagnosticArgumentKind::AvailabilityRange),
+      AvailabilityRangeVal(range) {}
+
+DiagnosticArgument::DiagnosticArgument(llvm::VersionTuple version)
+    : Kind(DiagnosticArgumentKind::VersionTuple), VersionVal(version) {}
+
+DiagnosticArgument::DiagnosticArgument(LayoutConstraint L)
+    : Kind(DiagnosticArgumentKind::LayoutConstraint), LayoutConstraintVal(L) {}
+
+DiagnosticArgument::DiagnosticArgument(ActorIsolation AI)
+    : Kind(DiagnosticArgumentKind::ActorIsolation), ActorIsolationVal(AI) {}
+
+DiagnosticArgument::DiagnosticArgument(IsolationSource IS)
+    : Kind(DiagnosticArgumentKind::IsolationSource), IsolationSourceVal(IS) {}
+
+DiagnosticArgument::DiagnosticArgument(DiagnosticInfo *D)
+    : Kind(DiagnosticArgumentKind::Diagnostic), DiagnosticVal(D) {}
+
+DiagnosticArgument::DiagnosticArgument(const clang::NamedDecl *ND)
+    : Kind(DiagnosticArgumentKind::ClangDecl), ClangDecl(ND) {}
+
+DiagnosticArgument::DiagnosticArgument(const clang::Type *Ty)
+    : Kind(DiagnosticArgumentKind::ClangType), ClangType(Ty) {}
+
+DiagnosticArgumentKind DiagnosticArgument::getKind() const { return Kind; }
+
+StringRef DiagnosticArgument::getAsString() const {
+  ASSERT(Kind == DiagnosticArgumentKind::String);
+  return StringVal;
+}
+
+int DiagnosticArgument::getAsInteger() const {
+  ASSERT(Kind == DiagnosticArgumentKind::Integer);
+  return IntegerVal;
+}
+
+unsigned DiagnosticArgument::getAsUnsigned() const {
+  ASSERT(Kind == DiagnosticArgumentKind::Unsigned);
+  return UnsignedVal;
+}
+
+DeclNameRef DiagnosticArgument::getAsIdentifier() const {
+  ASSERT(Kind == DiagnosticArgumentKind::Identifier);
+  return IdentifierVal;
+}
+
+ObjCSelector DiagnosticArgument::getAsObjCSelector() const {
+  ASSERT(Kind == DiagnosticArgumentKind::ObjCSelector);
+  return ObjCSelectorVal;
+}
+
+const Decl *DiagnosticArgument::getAsDecl() const {
+  ASSERT(Kind == DiagnosticArgumentKind::Decl);
+  return TheDecl;
+}
+
+Type DiagnosticArgument::getAsType() const {
+  ASSERT(Kind == DiagnosticArgumentKind::Type);
+  return TypeVal;
+}
+
+TypeRepr *DiagnosticArgument::getAsTypeRepr() const {
+  ASSERT(Kind == DiagnosticArgumentKind::TypeRepr);
+  return TyR;
+}
+
+FullyQualified<Type> DiagnosticArgument::getAsFullyQualifiedType() const {
+  ASSERT(Kind == DiagnosticArgumentKind::FullyQualifiedType);
+  return FullyQualifiedTypeVal;
+}
+
+WitnessType DiagnosticArgument::getAsWitnessType() const {
+  ASSERT(Kind == DiagnosticArgumentKind::WitnessType);
+  return WitnessTypeVal;
+}
+
+DescriptivePatternKind DiagnosticArgument::getAsDescriptivePatternKind() const {
+  ASSERT(Kind == DiagnosticArgumentKind::DescriptivePatternKind);
+  return DescriptivePatternKindVal;
+}
+
+ReferenceOwnership DiagnosticArgument::getAsReferenceOwnership() const {
+  ASSERT(Kind == DiagnosticArgumentKind::ReferenceOwnership);
+  return ReferenceOwnershipVal;
+}
+
+SelfAccessKind DiagnosticArgument::getAsSelfAccessKind() const {
+  ASSERT(Kind == DiagnosticArgumentKind::SelfAccessKind);
+  return SelfAccessKindVal;
+}
+
+StaticSpellingKind DiagnosticArgument::getAsStaticSpellingKind() const {
+  ASSERT(Kind == DiagnosticArgumentKind::StaticSpellingKind);
+  return StaticSpellingKindVal;
+}
+
+DescriptiveDeclKind DiagnosticArgument::getAsDescriptiveDeclKind() const {
+  ASSERT(Kind == DiagnosticArgumentKind::DescriptiveDeclKind);
+  return DescriptiveDeclKindVal;
+}
+
+StmtKind DiagnosticArgument::getAsDescriptiveStmtKind() const {
+  ASSERT(Kind == DiagnosticArgumentKind::DescriptiveStmtKind);
+  return DescriptiveStmtKindVal;
+}
+
+const DeclAttribute *DiagnosticArgument::getAsDeclAttribute() const {
+  ASSERT(Kind == DiagnosticArgumentKind::DeclAttribute);
+  return DeclAttributeVal;
+}
+
+const TypeAttribute *DiagnosticArgument::getAsTypeAttribute() const {
+  ASSERT(Kind == DiagnosticArgumentKind::TypeAttribute);
+  return TypeAttributeVal;
+}
+
+const AvailabilityDomain DiagnosticArgument::getAsAvailabilityDomain() const {
+  ASSERT(Kind == DiagnosticArgumentKind::AvailabilityDomain);
+  return AvailabilityDomainVal;
+}
+
+const AvailabilityRange DiagnosticArgument::getAsAvailabilityRange() const {
+  ASSERT(Kind == DiagnosticArgumentKind::AvailabilityRange);
+  return AvailabilityRangeVal;
+}
+
+llvm::VersionTuple DiagnosticArgument::getAsVersionTuple() const {
+  ASSERT(Kind == DiagnosticArgumentKind::VersionTuple);
+  return VersionVal;
+}
+
+LayoutConstraint DiagnosticArgument::getAsLayoutConstraint() const {
+  ASSERT(Kind == DiagnosticArgumentKind::LayoutConstraint);
+  return LayoutConstraintVal;
+}
+
+ActorIsolation DiagnosticArgument::getAsActorIsolation() const {
+  ASSERT(Kind == DiagnosticArgumentKind::ActorIsolation);
+  return ActorIsolationVal;
+}
+
+IsolationSource DiagnosticArgument::getAsIsolationSource() const {
+  ASSERT(Kind == DiagnosticArgumentKind::IsolationSource);
+  return IsolationSourceVal;
+}
+
+DiagnosticInfo *DiagnosticArgument::getAsDiagnostic() const {
+  ASSERT(Kind == DiagnosticArgumentKind::Diagnostic);
+  return DiagnosticVal;
+}
+
+const clang::NamedDecl *DiagnosticArgument::getAsClangDecl() const {
+  ASSERT(Kind == DiagnosticArgumentKind::ClangDecl);
+  return ClangDecl;
+}
+
+const clang::Type *DiagnosticArgument::getAsClangType() const {
+  ASSERT(Kind == DiagnosticArgumentKind::ClangType);
+  return ClangType;
+}
diff --git a/lib/AST/DiagnosticBridge.cpp b/lib/AST/DiagnosticBridge.cpp
index 859acbb22c2d6..92978c5a99ed6 100644
--- a/lib/AST/DiagnosticBridge.cpp
+++ b/lib/AST/DiagnosticBridge.cpp
@@ -26,6 +26,7 @@
 using namespace swift;
 
 #if SWIFT_BUILD_SWIFT_SYNTAX
+
 /// Enqueue a diagnostic with ASTGen's diagnostic rendering.
 static void addQueueDiagnostic(void *queuedDiagnostics,
                                void *perFrontendState,
@@ -37,32 +38,6 @@ static void addQueueDiagnostic(void *queuedDiagnostics,
                                            info.FormatArgs);
   }
 
-  BridgedDiagnosticSeverity severity;
-  switch (info.Kind) {
-  case DiagnosticKind::Error:
-    severity = BridgedDiagnosticSeverity::BridgedError;
-    break;
-
-  case DiagnosticKind::Warning:
-    severity = BridgedDiagnosticSeverity::BridgedWarning;
-    break;
-
-  case DiagnosticKind::Remark:
-    severity = BridgedDiagnosticSeverity::BridgedRemark;
-    break;
-
-  case DiagnosticKind::Note:
-    severity = BridgedDiagnosticSeverity::BridgedNote;
-    break;
-  }
-
-  // Map the highlight ranges.
-  SmallVector<BridgedCharSourceRange, 2> highlightRanges;
-  for (const auto &range : info.Ranges) {
-    if (range.isValid())
-      highlightRanges.push_back(range);
-  }
-
   StringRef documentationPath = info.CategoryDocumentationURL;
 
   SmallVector<BridgedFixIt, 2> fixIts;
@@ -73,10 +48,10 @@ static void addQueueDiagnostic(void *queuedDiagnostics,
   swift_ASTGen_addQueuedDiagnostic(
       queuedDiagnostics, perFrontendState,
       text.str(),
-      severity, info.Loc,
+      info.Kind, info.Loc,
       info.Category,
       documentationPath,
-      highlightRanges.data(), highlightRanges.size(),
+      info.Ranges.data(), info.Ranges.size(),
       llvm::ArrayRef<BridgedFixIt>(fixIts));
 
   // TODO: A better way to do this would be to pass the notes as an
@@ -87,6 +62,37 @@ static void addQueueDiagnostic(void *queuedDiagnostics,
   }
 }
 
+void DiagnosticBridge::emitDiagnosticWithoutLocation(
+    const DiagnosticInfo &info, llvm::raw_ostream &out, bool forceColors) {
+  ASSERT(queuedDiagnostics == nullptr);
+
+  // If we didn't have per-frontend state before, create it now.
+  if (!perFrontendState) {
+    perFrontendState = swift_ASTGen_createPerFrontendDiagnosticState();
+  }
+
+  llvm::SmallString<256> text;
+  {
+    llvm::raw_svector_ostream out(text);
+    DiagnosticEngine::formatDiagnosticText(out, info.FormatString,
+                                           info.FormatArgs);
+  }
+
+  BridgedStringRef bridgedRenderedString{nullptr, 0};
+  swift_ASTGen_renderSingleDiagnostic(
+      perFrontendState, text.str(), info.Kind, info.Category,
+      llvm::StringRef(info.CategoryDocumentationURL), forceColors ? 1 : 0,
+      &bridgedRenderedString);
+
+  auto renderedString = bridgedRenderedString.unbridged();
+  if (renderedString.data()) {
+    out << "<unknown>:0: ";
+    out.write(renderedString.data(), renderedString.size());
+    swift_ASTGen_freeBridgedString(renderedString);
+    out << "\n";
+  }
+}
+
 void DiagnosticBridge::enqueueDiagnostic(SourceManager &SM,
                                          const DiagnosticInfo &Info,
                                          unsigned innermostBufferID) {
diff --git a/lib/AST/DiagnosticConsumer.cpp b/lib/AST/DiagnosticConsumer.cpp
index 60ffdfbf13013..e43e01e2bdc18 100644
--- a/lib/AST/DiagnosticConsumer.cpp
+++ b/lib/AST/DiagnosticConsumer.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -40,9 +40,7 @@ DiagnosticInfo::FixIt::FixIt(CharSourceRange R, StringRef Str,
                                          formatForFixIts());
 }
 
-llvm::SMLoc DiagnosticConsumer::getRawLoc(SourceLoc loc) {
-  return loc.Value;
-}
+llvm::SMLoc DiagnosticConsumer::getRawLoc(SourceLoc loc) { return loc; }
 
 LLVM_ATTRIBUTE_UNUSED
 static bool hasDuplicateFileNames(
diff --git a/lib/AST/DiagnosticEngine.cpp b/lib/AST/DiagnosticEngine.cpp
index c487fcdf60ada..31f3275e7d5fb 100644
--- a/lib/AST/DiagnosticEngine.cpp
+++ b/lib/AST/DiagnosticEngine.cpp
@@ -16,6 +16,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/AST/DiagnosticEngine.h"
+#include "swift/AST/AvailabilityDomain.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTPrinter.h"
 #include "swift/AST/Decl.h"
@@ -176,6 +177,16 @@ std::optional<const DiagnosticInfo *> Diagnostic::getWrappedDiagnostic() const {
   return std::nullopt;
 }
 
+SourceLoc Diagnostic::getLocOrDeclLoc() const {
+  if (auto loc = getLoc())
+    return loc;
+
+  if (auto *D = getDecl())
+    return D->getLoc();
+
+  return SourceLoc();
+}
+
 static CharSourceRange toCharSourceRange(SourceManager &SM, SourceRange SR) {
   return CharSourceRange(SM, SR.Start, Lexer::getLocForEndOfToken(SM, SR.End));
 }
@@ -205,11 +216,14 @@ static char extractCharBefore(SourceManager &SM, SourceLoc Loc) {
   return chars[0];
 }
 
+detail::ActiveDiagnostic &InFlightDiagnostic::getActiveDiag() const {
+  return Engine->getActiveDiagnostic(*this);
+}
+
 InFlightDiagnostic &InFlightDiagnostic::highlight(SourceRange R) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
   if (Engine && R.isValid())
-    Engine->getActiveDiagnostic()
-        .addRange(toCharSourceRange(Engine->SourceMgr, R));
+    getDiag().addRange(toCharSourceRange(Engine->SourceMgr, R));
   return *this;
 }
 
@@ -217,15 +231,14 @@ InFlightDiagnostic &InFlightDiagnostic::highlightChars(SourceLoc Start,
                                                        SourceLoc End) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
   if (Engine && Start.isValid())
-    Engine->getActiveDiagnostic()
-        .addRange(toCharSourceRange(Engine->SourceMgr, Start, End));
+    getDiag().addRange(toCharSourceRange(Engine->SourceMgr, Start, End));
   return *this;
 }
 
 InFlightDiagnostic &InFlightDiagnostic::highlightChars(CharSourceRange Range) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
   if (Engine && Range.getStart().isValid())
-    Engine->getActiveDiagnostic().addRange(Range);
+    getDiag().addRange(Range);
   return *this;
 }
 
@@ -260,7 +273,7 @@ InFlightDiagnostic &InFlightDiagnostic::fixItRemove(SourceRange R) {
     charRange = CharSourceRange(charRange.getStart(),
                                 charRange.getByteLength()+1);
   }
-  Engine->getActiveDiagnostic().addFixIt(Diagnostic::FixIt(charRange, {}, {}));
+  getDiag().addFixIt(Diagnostic::FixIt(charRange, {}, {}));
   return *this;
 }
 
@@ -270,8 +283,7 @@ InFlightDiagnostic::fixItReplace(SourceRange R, StringRef FormatString,
   auto &SM = Engine->SourceMgr;
   auto charRange = toCharSourceRange(SM, R);
 
-  Engine->getActiveDiagnostic().addFixIt(
-      Diagnostic::FixIt(charRange, FormatString, Args));
+  getDiag().addFixIt(Diagnostic::FixIt(charRange, FormatString, Args));
   return *this;
 }
 
@@ -307,24 +319,17 @@ InFlightDiagnostic::fixItReplaceChars(SourceLoc Start, SourceLoc End,
                                       ArrayRef<DiagnosticArgument> Args) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
   if (Engine && Start.isValid())
-    Engine->getActiveDiagnostic().addFixIt(
-        Diagnostic::FixIt(toCharSourceRange(Engine->SourceMgr, Start, End),
-                          FormatString, Args));
+    getDiag().addFixIt(Diagnostic::FixIt(
+        toCharSourceRange(Engine->SourceMgr, Start, End), FormatString, Args));
   return *this;
 }
 
-SourceLoc
-DiagnosticEngine::getBestAddImportFixItLoc(const Decl *Member,
-                                           SourceFile *sourceFile) const {
+SourceLoc DiagnosticEngine::getBestAddImportFixItLoc(SourceFile *SF) const {
   auto &SM = SourceMgr;
 
   SourceLoc bestLoc;
-
-  auto SF =
-      sourceFile ? sourceFile : Member->getDeclContext()->getParentSourceFile();
-  if (!SF) {
+  if (!SF)
     return bestLoc;
-  }
 
   for (auto item : SF->getTopLevelItems()) {
     // If we found an import declaration, we want to insert after it.
@@ -356,30 +361,21 @@ DiagnosticEngine::getBestAddImportFixItLoc(const Decl *Member,
 
 InFlightDiagnostic &InFlightDiagnostic::fixItAddImport(StringRef ModuleName) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
-  auto Member = Engine->ActiveDiagnostic->getDecl();
-  SourceLoc bestLoc = Engine->getBestAddImportFixItLoc(Member);
-
-  if (bestLoc.isValid()) {
-    llvm::SmallString<64> importText;
-
-    // @_spi imports.
-    if (Member->isSPI()) {
-      auto spiGroups = Member->getSPIGroups();
-      if (!spiGroups.empty()) {
-        importText += "@_spi(";
-        importText += spiGroups[0].str();
-        importText += ") ";
-      }
-    }
+  auto decl = getDiag().getDecl();
+  if (!decl)
+    return *this;
 
-    importText += "import ";
-    importText += ModuleName;
-    importText += "\n";
+  auto bestLoc = Engine->getBestAddImportFixItLoc(
+      decl->getDeclContext()->getOutermostParentSourceFile());
+  if (!bestLoc.isValid())
+    return *this;
 
-    return fixItInsert(bestLoc, importText);
-  }
+  llvm::SmallString<64> importText;
+  importText += "import ";
+  importText += ModuleName;
+  importText += "\n";
 
-  return *this;
+  return fixItInsert(bestLoc, importText);
 }
 
 InFlightDiagnostic &
@@ -393,15 +389,17 @@ InFlightDiagnostic::fixItAddAttribute(const DeclAttribute *Attr,
                                       const ClosureExpr *E) {
   ASSERT(!E->isImplicit());
 
-  SourceLoc insertionLoc;
+  SourceLoc insertionLoc = E->getBracketRange().Start;
 
-  if (auto *paramList = E->getParameters()) {
-    // HACK: Don't set insertion loc to param list start loc if it's equal to
-    // closure start loc (meaning it's implicit).
-    // FIXME: Don't set the start loc of an implicit param list, or put an
-    // isImplicit bit on ParameterList.
-    if (paramList->getStartLoc() != E->getStartLoc()) {
-      insertionLoc = paramList->getStartLoc();
+  if (insertionLoc.isInvalid()) {
+    if (auto *paramList = E->getParameters()) {
+      // HACK: Don't set insertion loc to param list start loc if it's equal to
+      // closure start loc (meaning it's implicit).
+      // FIXME: Don't set the start loc of an implicit param list, or put an
+      // isImplicit bit on ParameterList.
+      if (paramList->getStartLoc() != E->getStartLoc()) {
+        insertionLoc = paramList->getStartLoc();
+      }
     }
   }
 
@@ -412,9 +410,20 @@ InFlightDiagnostic::fixItAddAttribute(const DeclAttribute *Attr,
   if (insertionLoc.isValid()) {
     return fixItInsert(insertionLoc, "%0 ", {Attr});
   } else {
-    insertionLoc = E->getBody()->getLBraceLoc();
+    auto *body = E->getBody();
+
+    insertionLoc = body->getLBraceLoc();
     ASSERT(insertionLoc.isValid());
-    return fixItInsertAfter(insertionLoc, " %0 in ", {Attr});
+
+    StringRef fixIt = " %0 in";
+    // If the first token in the body literally begins with the next char after
+    // '{', play it safe with a trailing space.
+    if (body->getContentStartLoc() ==
+        insertionLoc.getAdvancedLoc(/*ByteOffset=*/1)) {
+      fixIt = " %0 in ";
+    }
+
+    return fixItInsertAfter(insertionLoc, fixIt, {Attr});
   }
 }
 
@@ -430,16 +439,14 @@ InFlightDiagnostic &InFlightDiagnostic::fixItExchange(SourceRange R1,
   auto text1 = SM.extractText(charRange1);
   auto text2 = SM.extractText(charRange2);
 
-  Engine->getActiveDiagnostic().addFixIt(
-      Diagnostic::FixIt(charRange1, "%0", {text2}));
-  Engine->getActiveDiagnostic().addFixIt(
-      Diagnostic::FixIt(charRange2, "%0", {text1}));
+  getDiag().addFixIt(Diagnostic::FixIt(charRange1, "%0", {text2}));
+  getDiag().addFixIt(Diagnostic::FixIt(charRange2, "%0", {text1}));
   return *this;
 }
 
 InFlightDiagnostic &
 InFlightDiagnostic::limitBehavior(DiagnosticBehavior limit) {
-  Engine->getActiveDiagnostic().setBehaviorLimit(limit);
+  getDiag().setBehaviorLimit(limit);
   return *this;
 }
 
@@ -452,7 +459,7 @@ InFlightDiagnostic::limitBehaviorUntilSwiftVersion(
     // version. We do this before limiting the behavior, because
     // wrapIn will result in the behavior of the wrapping diagnostic.
     if (limit >= DiagnosticBehavior::Warning) {
-      if (majorVersion > 6) {
+      if (majorVersion >= version::Version::getFutureMajorLanguageVersion()) {
         wrapIn(diag::error_in_a_future_swift_lang_mode);
       } else {
         wrapIn(diag::error_in_swift_lang_mode, majorVersion);
@@ -472,6 +479,11 @@ InFlightDiagnostic::limitBehaviorUntilSwiftVersion(
   return *this;
 }
 
+InFlightDiagnostic &InFlightDiagnostic::warnUntilFutureSwiftVersion() {
+  using namespace version;
+  return warnUntilSwiftVersion(Version::getFutureMajorLanguageVersion());
+}
+
 InFlightDiagnostic &
 InFlightDiagnostic::warnUntilSwiftVersion(unsigned majorVersion) {
   return limitBehaviorUntilSwiftVersion(DiagnosticBehavior::Warning,
@@ -493,30 +505,33 @@ InFlightDiagnostic::wrapIn(const Diagnostic &wrapper) {
   // so we don't get a None return or influence future diagnostics.
   DiagnosticState tempState;
   Engine->state.swap(tempState);
-  llvm::SaveAndRestore<DiagnosticBehavior>
-      limit(Engine->getActiveDiagnostic().BehaviorLimit,
-            DiagnosticBehavior::Unspecified);
 
-  Engine->WrappedDiagnostics.push_back(*Engine->diagnosticInfoForDiagnostic(
-      Engine->getActiveDiagnostic(), /* includeDiagnosticName= */ false));
+  auto &ActiveDiag = getActiveDiag();
+  auto &Diag = ActiveDiag.Diag;
+
+  llvm::SaveAndRestore<DiagnosticBehavior> limit(
+      Diag.BehaviorLimit, DiagnosticBehavior::Unspecified);
+
+  ActiveDiag.WrappedDiagnostics.push_back(*Engine->diagnosticInfoForDiagnostic(
+      Diag, /* includeDiagnosticName= */ false));
 
   Engine->state.swap(tempState);
 
-  auto &wrapped = Engine->WrappedDiagnostics.back();
+  auto &wrapped = ActiveDiag.WrappedDiagnostics.back();
 
   // Copy and update its arg list.
-  Engine->WrappedDiagnosticArgs.emplace_back(wrapped.FormatArgs);
-  wrapped.FormatArgs = Engine->WrappedDiagnosticArgs.back();
+  ActiveDiag.WrappedDiagnosticArgs.emplace_back(wrapped.FormatArgs);
+  wrapped.FormatArgs = ActiveDiag.WrappedDiagnosticArgs.back();
 
   // Overwrite the ID and arguments with those from the wrapper.
-  Engine->getActiveDiagnostic().ID = wrapper.ID;
-  Engine->getActiveDiagnostic().Args = wrapper.Args;
+  Diag.ID = wrapper.ID;
+  Diag.Args = wrapper.Args;
   // Intentionally keeping the original GroupID here
 
   // Set the argument to the diagnostic being wrapped.
   ASSERT(wrapper.getArgs().front().getKind() ==
          DiagnosticArgumentKind::Diagnostic);
-  Engine->getActiveDiagnostic().Args.front() = &wrapped;
+  Diag.Args.front() = &wrapped;
 
   return *this;
 }
@@ -527,7 +542,7 @@ void InFlightDiagnostic::flush() {
   
   IsActive = false;
   if (Engine)
-    Engine->flushActiveDiagnostic();
+    Engine->endDiagnostic(*this);
 }
 
 void Diagnostic::addChildNote(Diagnostic &&D) {
@@ -874,18 +889,36 @@ static void formatDiagnosticArgument(StringRef Modifier,
       assert(Modifier.empty() && "Improper modifier for ValueDecl argument");
     }
 
-    // If it's an accessor, describe that and then switch to discussing its
-    // storage.
-    if (auto accessor = dyn_cast<AccessorDecl>(D)) {
-      Out << Decl::getDescriptiveKindName(D->getDescriptiveKind()) << " for ";
-      D = accessor->getStorage();
+    // Handle declarations representing an AvailabilityDomain specially.
+    if (auto VD = dyn_cast<ValueDecl>(D)) {
+      if (auto domain = AvailabilityDomain::forCustom(const_cast<ValueDecl *>(VD))) {
+        Out << "availability domain";
+
+        if (includeName) {
+          Out << " " << FormatOpts.OpeningQuotationMark;
+          Out << domain->getNameForDiagnostics();
+          Out << FormatOpts.ClosingQuotationMark;
+        }
+        break;
+      }
     }
 
-    // If it's an extension, describe that and then switch to discussing its
-    // nominal type.
-    if (auto ext = dyn_cast<ExtensionDecl>(D)) {
-      Out << Decl::getDescriptiveKindName(D->getDescriptiveKind()) << " of ";
-      D = ext->getSelfNominalTypeDecl();
+    if (includeName) {
+      if (auto accessor = dyn_cast<AccessorDecl>(D)) {
+        // If it's an accessor, describe that and then switch to discussing its
+        // storage declaration.
+        Out << Decl::getDescriptiveKindName(D->getDescriptiveKind()) << " for ";
+        D = accessor->getStorage();
+      } else if (auto ext = dyn_cast<ExtensionDecl>(D)) {
+        // If it's an extension with a valid bound type declaration, describe
+        // the extension itself then switch to discussing the bound
+        // declaration.
+        if (auto *nominal = ext->getSelfNominalTypeDecl()) {
+          Out << Decl::getDescriptiveKindName(D->getDescriptiveKind())
+              << " of ";
+          D = nominal;
+        }
+      }
     }
 
     // Figure out the name we want to print.
@@ -960,11 +993,10 @@ static void formatDiagnosticArgument(StringRef Modifier,
       needsQualification = typeSpellingIsAmbiguous(type, Args, printOptions);
     }
 
-    // If a type has an unresolved type, print it with syntax sugar removed for
+    // If a type has a bare error type, print it with syntax sugar removed for
     // clarity. For example, print `Array<_>` instead of `[_]`.
-    if (type->hasUnresolvedType()) {
+    if (type->hasBareError())
       type = type->getWithoutSyntaxSugar();
-    }
 
     if (needsQualification &&
         isa<OpaqueTypeArchetypeType>(type.getPointer()) &&
@@ -1090,6 +1122,26 @@ static void formatDiagnosticArgument(StringRef Modifier,
     }
     break;
   }
+  case DiagnosticArgumentKind::TypeAttribute: {
+    bool useAtStyle = true;
+    if (Modifier == "kind") {
+      useAtStyle = false;
+    } else {
+      ASSERT(Modifier.empty() &&
+             "Improper modifier for TypeAttribute argument");
+    }
+
+    if (!useAtStyle) {
+      Out << "attribute ";
+    }
+    Out << FormatOpts.OpeningQuotationMark;
+    if (useAtStyle) {
+      Out << '@';
+    }
+    Out << Arg.getAsTypeAttribute()->getAttrName();
+    Out << FormatOpts.ClosingQuotationMark;
+    break;
+  }
   case DiagnosticArgumentKind::AvailabilityDomain:
     assert(Modifier.empty() &&
            "Improper modifier for AvailabilityDomain argument");
@@ -1260,7 +1312,8 @@ llvm::cl::opt<bool> AssertOnError("swift-diagnostics-assert-on-error",
 llvm::cl::opt<bool> AssertOnWarning("swift-diagnostics-assert-on-warning",
                                     llvm::cl::init(false));
 
-DiagnosticBehavior DiagnosticState::determineBehavior(const Diagnostic &diag) {
+DiagnosticBehavior
+DiagnosticState::determineBehavior(const Diagnostic &diag) const {
   // We determine how to handle a diagnostic based on the following rules
   //   1) Map the diagnostic to its "intended" behavior, applying the behavior
   //      limit for this particular emission
@@ -1302,54 +1355,77 @@ DiagnosticBehavior DiagnosticState::determineBehavior(const Diagnostic &diag) {
     if (suppressWarnings)
       lvl = DiagnosticBehavior::Ignore;
   }
+
+  if (lvl == DiagnosticBehavior::Note) {
+    if (suppressNotes)
+      lvl = DiagnosticBehavior::Ignore;
+  }
   
   if (lvl == DiagnosticBehavior::Remark) {
     if (suppressRemarks)
       lvl = DiagnosticBehavior::Ignore;
   }
+  return lvl;
+}
 
-  //   5) Update current state for use during the next diagnostic
-  if (lvl == DiagnosticBehavior::Fatal) {
+void DiagnosticState::updateFor(DiagnosticBehavior behavior) {
+  // Update current state for use during the next diagnostic
+  if (behavior == DiagnosticBehavior::Fatal) {
     fatalErrorOccurred = true;
     anyErrorOccurred = true;
-  } else if (lvl == DiagnosticBehavior::Error) {
+  } else if (behavior == DiagnosticBehavior::Error) {
     anyErrorOccurred = true;
   }
 
   ASSERT((!AssertOnError || !anyErrorOccurred) && "We emitted an error?!");
-  ASSERT((!AssertOnWarning || (lvl != DiagnosticBehavior::Warning)) &&
+  ASSERT((!AssertOnWarning || (behavior != DiagnosticBehavior::Warning)) &&
          "We emitted a warning?!");
 
-  previousBehavior = lvl;
-  return lvl;
+  previousBehavior = behavior;
+}
+
+InFlightDiagnostic DiagnosticEngine::beginDiagnostic(const Diagnostic &D) {
+  unsigned idx = ActiveDiagnostics.size();
+  ActiveDiagnostics.emplace_back(D);
+  NumActiveDiags += 1;
+  return InFlightDiagnostic(*this, idx);
 }
 
-void DiagnosticEngine::flushActiveDiagnostic() {
-  assert(ActiveDiagnostic && "No active diagnostic to flush");
-  handleDiagnostic(std::move(*ActiveDiagnostic));
-  ActiveDiagnostic.reset();
+void DiagnosticEngine::endDiagnostic(const InFlightDiagnostic &D) {
+  // Decrement the number of active diagnostics. We wait until all in-flight
+  // diagnostics have ended to ensure a FIFO ordering.
+  ASSERT(NumActiveDiags > 0 && "Unbalanced call to endDiagnostic");
+  NumActiveDiags -= 1;
+  if (NumActiveDiags > 0)
+    return;
+
+  for (auto &D : ActiveDiagnostics)
+    handleDiagnostic(std::move(D));
+
+  ActiveDiagnostics.clear();
 }
 
-void DiagnosticEngine::handleDiagnostic(Diagnostic &&diag) {
+detail::ActiveDiagnostic &
+DiagnosticEngine::getActiveDiagnostic(const InFlightDiagnostic &diag) {
+  return ActiveDiagnostics[diag.Idx];
+}
+
+void DiagnosticEngine::handleDiagnostic(detail::ActiveDiagnostic &&diag) {
   if (TransactionCount == 0) {
-    emitDiagnostic(diag);
-    WrappedDiagnostics.clear();
-    WrappedDiagnosticArgs.clear();
+    emitDiagnostic(diag.Diag);
   } else {
-    onTentativeDiagnosticFlush(diag);
+    onTentativeDiagnosticFlush(diag.Diag);
     TentativeDiagnostics.emplace_back(std::move(diag));
   }
 }
 
 void DiagnosticEngine::clearTentativeDiagnostics() {
   TentativeDiagnostics.clear();
-  WrappedDiagnostics.clear();
-  WrappedDiagnosticArgs.clear();
 }
 
 void DiagnosticEngine::emitTentativeDiagnostics() {
   for (auto &diag : TentativeDiagnostics) {
-    emitDiagnostic(diag);
+    emitDiagnostic(diag.Diag);
   }
   clearTentativeDiagnostics();
 }
@@ -1366,24 +1442,24 @@ std::optional<DiagnosticInfo>
 DiagnosticEngine::diagnosticInfoForDiagnostic(const Diagnostic &diagnostic,
                                               bool includeDiagnosticName) {
   auto behavior = state.determineBehavior(diagnostic);
+  state.updateFor(behavior);
+
   if (behavior == DiagnosticBehavior::Ignore)
     return std::nullopt;
 
   // Figure out the source location.
-  SourceLoc loc = diagnostic.getLoc();
+  SourceLoc loc = diagnostic.getLocOrDeclLoc();
   if (loc.isInvalid() && diagnostic.getDecl()) {
+    // If the location of the decl is invalid, try to pretty-print it into a
+    // buffer and capture the source location there. Make sure we don't have an
+    // active request running since printing AST can kick requests that may
+    // themselves emit diagnostics. This won't help the underlying cycle, but it
+    // at least stops us from overflowing the stack.
     const Decl *decl = diagnostic.getDecl();
-    // If a declaration was provided instead of a location, and that declaration
-    // has a location we can point to, use that location.
-    loc = decl->getLoc();
-
-    // If the location of the decl is invalid still, try to pretty-print the
-    // declaration into a buffer and capture the source location there.
-    if (loc.isInvalid()) {
-      loc = evaluateOrDefault(
-          decl->getASTContext().evaluator, PrettyPrintDeclRequest{decl},
-          SourceLoc());
-    }
+    PrettyPrintDeclRequest req(decl);
+    auto &eval = decl->getASTContext().evaluator;
+    if (!eval.hasActiveRequest(req))
+      loc = evaluateOrDefault(eval, req, SourceLoc());
   }
 
   auto groupID = diagnostic.getGroupID();
@@ -1452,7 +1528,7 @@ getGeneratedSourceInfoMacroName(const GeneratedSourceInfo &info) {
       }
 
       auto expansionDecl =
-          cast<MacroExpansionDecl>(expansionNode.get<Decl *>());
+          cast<MacroExpansionDecl>(cast<Decl *>(expansionNode));
       return expansionDecl->getMacroName().getFullName();
     }
 
@@ -1713,6 +1789,20 @@ void DiagnosticEngine::onTentativeDiagnosticFlush(Diagnostic &diagnostic) {
   }
 }
 
+void DiagnosticQueue::forEach(
+    llvm::function_ref<void(const Diagnostic &)> body) const {
+  for (auto &activeDiag : QueueEngine.TentativeDiagnostics)
+    body(activeDiag.Diag);
+}
+
+void DiagnosticQueue::filter(
+    llvm::function_ref<bool(const Diagnostic &)> predicate) {
+  llvm::erase_if(QueueEngine.TentativeDiagnostics,
+                 [&](detail::ActiveDiagnostic &activeDiag) {
+                   return !predicate(activeDiag.Diag);
+                 });
+}
+
 EncodedDiagnosticMessage::EncodedDiagnosticMessage(StringRef S)
     : Message(Lexer::getEncodedStringSegment(S, Buf, /*IsFirstSegment=*/true,
                                              /*IsLastSegment=*/true,
diff --git a/lib/AST/DistributedDecl.cpp b/lib/AST/DistributedDecl.cpp
index 8ab8b8ed5a4fb..3d9cf93799cc5 100644
--- a/lib/AST/DistributedDecl.cpp
+++ b/lib/AST/DistributedDecl.cpp
@@ -203,7 +203,7 @@ Type swift::getDistributedActorSystemType(NominalTypeDecl *actor) {
   // Dig out the actor system type.
   Type selfType = actor->getSelfInterfaceType();
   auto conformance = lookupConformance(selfType, DA);
-  return conformance.getTypeWitnessByName(selfType, C.Id_ActorSystem);
+  return conformance.getTypeWitnessByName(C.Id_ActorSystem);
 }
 
 Type swift::getDistributedActorIDType(NominalTypeDecl *actor) {
@@ -220,7 +220,7 @@ static Type getTypeWitnessByName(NominalTypeDecl *type, ProtocolDecl *protocol,
   auto conformance = lookupConformance(selfType, protocol);
   if (!conformance || conformance.isInvalid())
     return Type();
-  return conformance.getTypeWitnessByName(selfType, member);
+  return conformance.getTypeWitnessByName(member);
 }
 
 Type swift::getDistributedActorSerializationType(
@@ -301,8 +301,7 @@ Type swift::getDistributedSerializationRequirementType(
   if (conformance.isInvalid())
     return Type();
 
-  return conformance.getTypeWitnessByName(selfType,
-                                          ctx.Id_SerializationRequirement);
+  return conformance.getTypeWitnessByName(ctx.Id_SerializationRequirement);
 }
 
 AbstractFunctionDecl *
@@ -365,11 +364,10 @@ Type swift::getAssociatedTypeOfDistributedSystemOfActor(
   auto actorConformance =
       lookupConformance(
           actorType->getDeclaredInterfaceType(), actorProtocol);
-  if (!actorConformance || actorConformance.isInvalid())
+  if (actorConformance.isInvalid())
     return Type();
 
-  auto subs = SubstitutionMap::getProtocolSubstitutions(
-      actorProtocol, actorType->getDeclaredInterfaceType(), actorConformance);
+  auto subs = SubstitutionMap::getProtocolSubstitutions(actorConformance);
 
   memberTy = memberTy.subst(subs);
 
diff --git a/lib/AST/Evaluator.cpp b/lib/AST/Evaluator.cpp
index 13ba2bc733f7d..dcc1c55423f4f 100644
--- a/lib/AST/Evaluator.cpp
+++ b/lib/AST/Evaluator.cpp
@@ -19,6 +19,7 @@
 #include "swift/AST/DiagnosticEngine.h"
 #include "swift/AST/TypeCheckRequests.h" // for ResolveMacroRequest
 #include "swift/Basic/Assertions.h"
+#include "swift/Basic/Defer.h"
 #include "swift/Basic/LangOptions.h"
 #include "swift/Basic/Range.h"
 #include "swift/Basic/SourceManager.h"
@@ -123,11 +124,44 @@ void Evaluator::diagnoseCycle(const ActiveRequest &request) {
     OS << "\n";
   }
 
-  request.diagnoseCycle(diags);
-  for (const auto &step : llvm::reverse(activeRequests)) {
-    if (step == request) return;
+  // Perform some filtering to avoid emitting duplicate 'through reference here'
+  // notes.
+  DiagnosticQueue cycleDiags(diags, /*emitOnDestruction*/ true);
+  SWIFT_DEFER {
+    auto isDefaultStepNote = [](const Diagnostic &diag) -> bool {
+      return diag.getID() == diag::circular_reference_through.ID;
+    };
+    // First populate seen locs for everything except default step notes. If
+    // we have a diagnostic or custom note at a given location we want to prefer
+    // that over the default step note.
+    llvm::DenseSet<SourceLoc> seenLocs;
+    cycleDiags.forEach([&](const Diagnostic &diag) {
+      if (isDefaultStepNote(diag))
+        return;
+
+      if (auto loc = diag.getLocOrDeclLoc())
+        seenLocs.insert(loc);
+    });
+    // Then we can filter out unnecessary default step notes.
+    cycleDiags.filter([&](const Diagnostic &diag) -> bool {
+      if (!isDefaultStepNote(diag))
+        return true;
+
+      auto loc = diag.getLocOrDeclLoc();
+      return loc && seenLocs.insert(loc).second;
+    });
+  };
+
+  request.diagnoseCycle(cycleDiags.getDiags());
 
-    step.noteCycleStep(diags);
+  for (const auto &step : llvm::reverse(activeRequests)) {
+    if (step == request) {
+      // Note that we diagnosed a cycle for the outermost step to ensure it
+      // also returns a cyclic result.
+      diagnosedActiveCycles.insert(step);
+      return;
+    }
+    step.noteCycleStep(cycleDiags.getDiags());
   }
 
   llvm_unreachable("Diagnosed a cycle but it wasn't represented in the stack");
diff --git a/lib/AST/ExistentialGeneralization.cpp b/lib/AST/ExistentialGeneralization.cpp
index 4060c60b1a72e..d12e2df63b305 100644
--- a/lib/AST/ExistentialGeneralization.cpp
+++ b/lib/AST/ExistentialGeneralization.cpp
@@ -68,10 +68,11 @@ class Generalizer : public CanTypeVisitor<Generalizer, Type> {
       assert(it != substTypes.end());
       return it->second;
     };
-    auto lookupConformance = [&](CanType dependentType,
-                                 Type conformingReplacementType,
+    auto lookupConformance = [&](InFlightSubstitution &IFS,
+                                 Type dependentType,
                                  ProtocolDecl *conformedProtocol) {
-      auto it = substConformances.find({dependentType, conformedProtocol});
+      auto it = substConformances.find(
+          {dependentType->getCanonicalType(), conformedProtocol});
       assert(it != substConformances.end());
       return it->second;
     };
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index e5d7bfee031fe..8aff969050f5b 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -414,7 +414,6 @@ ConcreteDeclRef Expr::getReferencedDecl(bool stopAtParenExpr) const {
 
   PASS_THROUGH_REFERENCE(Load, getSubExpr);
   NO_REFERENCE(DestructureTuple);
-  NO_REFERENCE(UnresolvedTypeConversion);
   PASS_THROUGH_REFERENCE(ABISafeConversion, getSubExpr);
   PASS_THROUGH_REFERENCE(FunctionConversion, getSubExpr);
   PASS_THROUGH_REFERENCE(CovariantFunctionConversion, getSubExpr);
@@ -783,7 +782,6 @@ bool Expr::canAppendPostfixExpression(bool appendingPostfixOperator) const {
   case ExprKind::Load:
   case ExprKind::ABISafeConversion:
   case ExprKind::DestructureTuple:
-  case ExprKind::UnresolvedTypeConversion:
   case ExprKind::FunctionConversion:
   case ExprKind::CovariantFunctionConversion:
   case ExprKind::CovariantReturnConversion:
@@ -993,7 +991,6 @@ bool Expr::isValidParentOfTypeExpr(Expr *typeExpr) const {
   case ExprKind::Binary:
   case ExprKind::Load:
   case ExprKind::DestructureTuple:
-  case ExprKind::UnresolvedTypeConversion:
   case ExprKind::ABISafeConversion:
   case ExprKind::FunctionConversion:
   case ExprKind::CovariantFunctionConversion:
@@ -1089,7 +1086,14 @@ StringRef LiteralExpr::getLiteralKindDescription() const {
   llvm_unreachable("Unhandled literal");
 }
 
-IntegerLiteralExpr * IntegerLiteralExpr::createFromUnsigned(ASTContext &C, unsigned value, SourceLoc loc) {
+void BuiltinLiteralExpr::setBuiltinInitializer(
+    ConcreteDeclRef builtinInitializer) {
+  ASSERT(builtinInitializer);
+  BuiltinInitializer = builtinInitializer;
+}
+
+IntegerLiteralExpr * IntegerLiteralExpr::createFromUnsigned(
+    ASTContext &C, unsigned value, SourceLoc loc) {
   llvm::SmallString<8> Scratch;
   llvm::APInt(sizeof(unsigned)*8, value).toString(Scratch, 10, /*signed*/ false);
   auto Text = C.AllocateCopy(StringRef(Scratch));
@@ -1366,9 +1370,9 @@ CaptureListEntry CaptureListEntry::createParsed(
     SourceRange ownershipRange, Identifier name, SourceLoc nameLoc,
     SourceLoc equalLoc, Expr *initializer, DeclContext *DC) {
 
-  auto introducer =
-      (ownershipKind != ReferenceOwnership::Weak ? VarDecl::Introducer::Let
-                                                 : VarDecl::Introducer::Var);
+  bool forceVar = ownershipKind == ReferenceOwnership::Weak &&
+                  !Ctx.LangOpts.hasFeature(Feature::ImmutableWeakCaptures);
+  auto introducer = forceVar ? VarDecl::Introducer::Var : VarDecl::Introducer::Let;
   auto *VD =
       new (Ctx) VarDecl(/*isStatic==*/false, introducer, nameLoc, name, DC);
 
@@ -1994,9 +1998,10 @@ unsigned AbstractClosureExpr::getDiscriminator() const {
   }
 
   if (getRawDiscriminator() == InvalidDiscriminator) {
-    llvm::errs() << "Closure does not have an assigned discriminator:\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Closure does not have an assigned discriminator:\n";
+      this->dump(out);
+    });
   }
 
   return getRawDiscriminator();
@@ -2219,7 +2224,7 @@ void AutoClosureExpr::setBody(Expr *E) {
 }
 
 Expr *AutoClosureExpr::getSingleExpressionBody() const {
-  return cast<ReturnStmt>(Body->getLastElement().get<Stmt *>())->getResult();
+  return cast<ReturnStmt>(cast<Stmt *>(Body->getLastElement()))->getResult();
 }
 
 Expr *AutoClosureExpr::getUnwrappedCurryThunkExpr() const {
@@ -2441,11 +2446,22 @@ bool Expr::isSelfExprOf(const AbstractFunctionDecl *AFD, bool sameBase) const {
   return false;
 }
 
-TypeValueExpr *TypeValueExpr::createForDecl(DeclNameLoc loc, 
-                                            GenericTypeParamDecl *paramDecl) {
-  auto &ctx = paramDecl->getASTContext();
+TypeValueExpr *TypeValueExpr::createForDecl(DeclNameLoc loc, TypeDecl *decl,
+                                            DeclContext *dc) {
+  auto &ctx = decl->getASTContext();
   ASSERT(loc.isValid());
-  return new (ctx) TypeValueExpr(loc, paramDecl);
+  auto repr = UnqualifiedIdentTypeRepr::create(ctx, loc, decl->createNameRef());
+  repr->setValue(decl, dc);
+  return new (ctx) TypeValueExpr(repr);
+}
+
+GenericTypeParamDecl *TypeValueExpr::getParamDecl() const {
+  auto declRefRepr = cast<DeclRefTypeRepr>(getRepr());
+  return cast<GenericTypeParamDecl>(declRefRepr->getBoundDecl());
+}
+
+SourceRange TypeValueExpr::getSourceRange() const {
+  return getRepr()->getSourceRange();
 }
 
 ExistentialArchetypeType *OpenExistentialExpr::getOpenedArchetype() const {
@@ -2622,7 +2638,7 @@ SingleValueStmtExpr *SingleValueStmtExpr::createWithWrappedBranches(
       continue;
 
     auto &result = BS->getElements().back();
-    assert(result.is<Expr *>() || result.is<Stmt *>());
+    assert(isa<Expr *>(result) || isa<Stmt *>(result));
 
     // Wrap a statement in a SingleValueStmtExpr.
     if (auto *S = result.dyn_cast<Stmt *>()) {
@@ -2695,7 +2711,7 @@ bool SingleValueStmtExpr::isLastElementImplicitResult(
   auto elt = BS->getLastElement();
 
   // Expressions are always valid.
-  if (elt.is<Expr *>())
+  if (isa<Expr *>(elt))
     return true;
 
   if (auto *S = elt.dyn_cast<Stmt *>()) {
@@ -2747,6 +2763,8 @@ SingleValueStmtExpr::Kind SingleValueStmtExpr::getStmtKind() const {
     return Kind::Do;
   case StmtKind::DoCatch:
     return Kind::DoCatch;
+  case StmtKind::ForEach:
+    return Kind::For;
   default:
     llvm_unreachable("Unhandled kind!");
   }
@@ -2765,6 +2783,9 @@ SingleValueStmtExpr::getBranches(SmallVectorImpl<Stmt *> &scratch) const {
     return scratch;
   case Kind::DoCatch:
     return cast<DoCatchStmt>(getStmt())->getBranches(scratch);
+  case Kind::For:
+    scratch.push_back(cast<ForEachStmt>(getStmt())->getBody());
+    return scratch;
   }
   llvm_unreachable("Unhandled case in switch!");
 }
@@ -2891,7 +2912,7 @@ TypeJoinExpr::TypeJoinExpr(llvm::PointerUnion<DeclRefExpr *, TypeBase *> result,
     assert(varRef);
     Var = varRef;
   } else {
-    auto joinType = Type(result.get<TypeBase *>());
+    auto joinType = Type(cast<TypeBase *>(result));
     assert(joinType && "expected non-null type");
     setType(joinType);
   }
@@ -2899,7 +2920,7 @@ TypeJoinExpr::TypeJoinExpr(llvm::PointerUnion<DeclRefExpr *, TypeBase *> result,
   Bits.TypeJoinExpr.NumElements = elements.size();
   // Copy elements.
   std::uninitialized_copy(elements.begin(), elements.end(),
-                          getTrailingObjects<Expr *>());
+                          getTrailingObjects());
 }
 
 TypeJoinExpr *TypeJoinExpr::createImpl(
@@ -3077,7 +3098,7 @@ Type ThrownErrorDestination::getThrownErrorType() const {
   if (auto type = storage.dyn_cast<TypeBase *>())
     return Type(type);
 
-  auto conversion = storage.get<Conversion *>();
+  auto conversion = cast<Conversion *>(storage);
   return conversion->thrownError->getType();
 }
 
@@ -3088,7 +3109,7 @@ Type ThrownErrorDestination::getContextErrorType() const {
   if (auto type = storage.dyn_cast<TypeBase *>())
     return Type(type);
 
-  auto conversion = storage.get<Conversion *>();
+  auto conversion = cast<Conversion *>(storage);
   return conversion->conversion->getType();
 }
 
diff --git a/lib/AST/FeatureSet.cpp b/lib/AST/FeatureSet.cpp
index 2197edead58e8..cb8910241d07d 100644
--- a/lib/AST/FeatureSet.cpp
+++ b/lib/AST/FeatureSet.cpp
@@ -12,6 +12,7 @@
 
 #include "FeatureSet.h"
 
+#include "swift/AST/ASTWalker.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/ExistentialLayout.h"
 #include "swift/AST/GenericParamList.h"
@@ -83,6 +84,7 @@ UNINTERESTING_FEATURE(CodeItemMacros)
 UNINTERESTING_FEATURE(PreambleMacros)
 UNINTERESTING_FEATURE(TupleConformances)
 UNINTERESTING_FEATURE(SymbolLinkageMarkers)
+UNINTERESTING_FEATURE(DeferredCodeGen)
 UNINTERESTING_FEATURE(LazyImmediate)
 UNINTERESTING_FEATURE(MoveOnlyClasses)
 UNINTERESTING_FEATURE(NoImplicitCopy)
@@ -90,7 +92,6 @@ UNINTERESTING_FEATURE(OldOwnershipOperatorSpellings)
 UNINTERESTING_FEATURE(MoveOnlyEnumDeinits)
 UNINTERESTING_FEATURE(MoveOnlyTuples)
 UNINTERESTING_FEATURE(MoveOnlyPartialReinitialization)
-UNINTERESTING_FEATURE(LayoutPrespecialization)
 UNINTERESTING_FEATURE(AccessLevelOnImport)
 UNINTERESTING_FEATURE(AllowNonResilientAccessInPackage)
 UNINTERESTING_FEATURE(ClientBypassResilientAccessInPackage)
@@ -108,7 +109,6 @@ UNINTERESTING_FEATURE(UnqualifiedLookupValidation)
 UNINTERESTING_FEATURE(ImplicitSome)
 UNINTERESTING_FEATURE(ParserASTGen)
 UNINTERESTING_FEATURE(BuiltinMacros)
-UNINTERESTING_FEATURE(ImportSymbolicCXXDecls)
 UNINTERESTING_FEATURE(GenerateBindingsForThrowingFunctionsInCXX)
 UNINTERESTING_FEATURE(ReferenceBindings)
 UNINTERESTING_FEATURE(BuiltinModule)
@@ -116,6 +116,7 @@ UNINTERESTING_FEATURE(RegionBasedIsolation)
 UNINTERESTING_FEATURE(PlaygroundExtendedCallbacks)
 UNINTERESTING_FEATURE(ThenStatements)
 UNINTERESTING_FEATURE(DoExpressions)
+UNINTERESTING_FEATURE(ForExpressions)
 UNINTERESTING_FEATURE(ImplicitLastExprResults)
 UNINTERESTING_FEATURE(RawLayout)
 UNINTERESTING_FEATURE(Embedded)
@@ -123,77 +124,13 @@ UNINTERESTING_FEATURE(Volatile)
 UNINTERESTING_FEATURE(SuppressedAssociatedTypes)
 UNINTERESTING_FEATURE(StructLetDestructuring)
 UNINTERESTING_FEATURE(MacrosOnImports)
-UNINTERESTING_FEATURE(AsyncCallerExecution)
-UNINTERESTING_FEATURE(ExtensibleEnums)
+UNINTERESTING_FEATURE(NonisolatedNonsendingByDefault)
 UNINTERESTING_FEATURE(KeyPathWithMethodMembers)
+UNINTERESTING_FEATURE(ImportMacroAliases)
+UNINTERESTING_FEATURE(NoExplicitNonIsolated)
 
-static bool usesFeatureNonescapableTypes(Decl *decl) {
-  auto containsNonEscapable =
-      [](SmallVectorImpl<InverseRequirement> &inverseReqs) {
-        auto foundIt =
-            llvm::find_if(inverseReqs, [](InverseRequirement inverseReq) {
-              if (inverseReq.getKind() == InvertibleProtocolKind::Escapable) {
-                return true;
-              }
-              return false;
-            });
-        return foundIt != inverseReqs.end();
-      };
-
-  if (auto *valueDecl = dyn_cast<ValueDecl>(decl)) {
-    if (isa<StructDecl, EnumDecl, ClassDecl>(decl)) {
-      auto *nominalDecl = cast<NominalTypeDecl>(valueDecl);
-      InvertibleProtocolSet inverses;
-      bool anyObject = false;
-      getDirectlyInheritedNominalTypeDecls(nominalDecl, inverses, anyObject);
-      if (inverses.containsEscapable()) {
-        return true;
-      }
-    }
-
-    if (auto proto = dyn_cast<ProtocolDecl>(decl)) {
-      auto reqSig = proto->getRequirementSignature();
-
-      SmallVector<Requirement, 2> reqs;
-      SmallVector<InverseRequirement, 2> inverses;
-      reqSig.getRequirementsWithInverses(proto, reqs, inverses);
-      if (containsNonEscapable(inverses))
-        return true;
-    }
-
-    if (isa<AbstractFunctionDecl>(valueDecl) ||
-        isa<AbstractStorageDecl>(valueDecl)) {
-      if (valueDecl->getInterfaceType().findIf([&](Type type) -> bool {
-            if (auto *nominalDecl = type->getAnyNominal()) {
-              if (isa<StructDecl, EnumDecl, ClassDecl>(nominalDecl))
-                return usesFeatureNonescapableTypes(nominalDecl);
-            }
-            return false;
-          })) {
-        return true;
-      }
-    }
-  }
-
-  if (auto *ext = dyn_cast<ExtensionDecl>(decl)) {
-    if (auto *nominal = ext->getExtendedNominal())
-      if (usesFeatureNonescapableTypes(nominal))
-        return true;
-  }
-
-  if (auto *genCtx = decl->getAsGenericContext()) {
-    if (auto genericSig = genCtx->getGenericSignature()) {
-      SmallVector<Requirement, 2> reqs;
-      SmallVector<InverseRequirement, 2> inverseReqs;
-      genericSig->getRequirementsWithInverses(reqs, inverseReqs);
-      if (containsNonEscapable(inverseReqs)) {
-        return true;
-      }
-    }
-  }
-
-  return false;
-}
+// TODO: Return true for inlinable function bodies with module selectors in them
+UNINTERESTING_FEATURE(ModuleSelector)
 
 static bool usesFeatureInlineArrayTypeSugar(Decl *D) {
   return usesTypeMatching(D, [&](Type ty) {
@@ -202,64 +139,42 @@ static bool usesFeatureInlineArrayTypeSugar(Decl *D) {
 }
 
 UNINTERESTING_FEATURE(StaticExclusiveOnly)
+UNINTERESTING_FEATURE(ManualOwnership)
 UNINTERESTING_FEATURE(ExtractConstantsFromMembers)
 UNINTERESTING_FEATURE(GroupActorErrors)
 UNINTERESTING_FEATURE(SameElementRequirements)
+UNINTERESTING_FEATURE(SendingArgsAndResults)
 
-static bool usesFeatureSendingArgsAndResults(Decl *decl) {
-  auto isFunctionTypeWithSending = [](Type type) {
-      auto fnType = type->getAs<AnyFunctionType>();
-      if (!fnType)
-        return false;
-
-      if (fnType->hasExtInfo() && fnType->hasSendingResult())
-        return true;
-
-      return llvm::any_of(fnType->getParams(),
-                          [](AnyFunctionType::Param param) {
-                            return param.getParameterFlags().isSending();
-                          });
-  };
-  auto declUsesFunctionTypesThatUseSending = [&](Decl *decl) {
-    return usesTypeMatching(decl, isFunctionTypeWithSending);
-  };
-
-  if (auto *pd = dyn_cast<ParamDecl>(decl)) {
-    if (pd->isSending()) {
-      return true;
+static bool findUnderscoredLifetimeAttr(Decl *decl) {
+  auto hasUnderscoredLifetimeAttr = [](Decl *decl) {
+    if (!decl->getAttrs().hasAttribute<LifetimeAttr>()) {
+      return false;
     }
+    // Since we ban mixing @lifetime and @_lifetime on the same decl, checking
+    // any one LifetimeAttr on the decl is sufficient.
+    // FIXME: Implement the ban.
+    return decl->getAttrs().getAttribute<LifetimeAttr>()->isUnderscored();
+  };
 
-    if (declUsesFunctionTypesThatUseSending(pd))
-      return true;
-  }
-
-  if (auto *fDecl = dyn_cast<AbstractFunctionDecl>(decl)) {
-    // First check for param decl results.
-    if (llvm::any_of(fDecl->getParameters()->getArray(), [](ParamDecl *pd) {
-          return usesFeatureSendingArgsAndResults(pd);
-        }))
-      return true;
-    if (declUsesFunctionTypesThatUseSending(decl))
-      return true;
+  switch (decl->getKind()) {
+  case DeclKind::Var: {
+    auto *var = cast<VarDecl>(decl);
+    return llvm::any_of(var->getAllAccessors(), hasUnderscoredLifetimeAttr);
   }
-
-  // Check if we have a pattern binding decl for a function that has sending
-  // parameters and results.
-  if (auto *pbd = dyn_cast<PatternBindingDecl>(decl)) {
-    for (auto index : range(pbd->getNumPatternEntries())) {
-      auto *pattern = pbd->getPattern(index);
-      if (pattern->hasType() && isFunctionTypeWithSending(pattern->getType()))
-        return true;
-    }
+  default:
+    return hasUnderscoredLifetimeAttr(decl);
   }
-
-  return false;
 }
 
 static bool usesFeatureLifetimeDependence(Decl *decl) {
   if (decl->getAttrs().hasAttribute<LifetimeAttr>()) {
+    if (findUnderscoredLifetimeAttr(decl)) {
+      // Experimental feature Lifetimes will guard the decl.
+      return false;
+    }
     return true;
   }
+
   if (auto *afd = dyn_cast<AbstractFunctionDecl>(decl)) {
     return afd->getInterfaceType()
       ->getAs<AnyFunctionType>()
@@ -271,34 +186,67 @@ static bool usesFeatureLifetimeDependence(Decl *decl) {
   return false;
 }
 
-UNINTERESTING_FEATURE(DynamicActorIsolation)
-UNINTERESTING_FEATURE(NonfrozenEnumExhaustivity)
-UNINTERESTING_FEATURE(ClosureIsolation)
-UNINTERESTING_FEATURE(Extern)
-UNINTERESTING_FEATURE(ConsumeSelfInDeinit)
+static bool usesFeatureLifetimes(Decl *decl) {
+  return findUnderscoredLifetimeAttr(decl);
+}
 
-static bool usesFeatureBitwiseCopyable2(Decl *decl) {
-  if (!decl->getModuleContext()->isStdlibModule()) {
+static bool usesFeatureInoutLifetimeDependence(Decl *decl) {
+  auto hasInoutLifetimeDependence = [](Decl *decl) {
+    for (auto attr : decl->getAttrs().getAttributes<LifetimeAttr>()) {
+      for (auto source : attr->getLifetimeEntry()->getSources()) {
+        if (source.getParsedLifetimeDependenceKind() ==
+            ParsedLifetimeDependenceKind::Inout) {
+          return true;
+        }
+      }
+    }
     return false;
+  };
+
+  switch (decl->getKind()) {
+  case DeclKind::Var: {
+    auto *var = cast<VarDecl>(decl);
+    return llvm::any_of(var->getAllAccessors(), hasInoutLifetimeDependence);
   }
-  if (auto *proto = dyn_cast<ProtocolDecl>(decl)) {
-    return proto->getNameStr() == "BitwiseCopyable";
+  default:
+    return hasInoutLifetimeDependence(decl);
   }
-  if (auto *typealias = dyn_cast<TypeAliasDecl>(decl)) {
-    return typealias->getNameStr() == "_BitwiseCopyable";
+}
+
+static bool usesFeatureLifetimeDependenceMutableAccessors(Decl *decl) {
+  if (!isa<VarDecl>(decl)) {
+    return false;
   }
-  return false;
+  auto var = cast<VarDecl>(decl);
+  return var->isGetterMutating() && !var->getTypeInContext()->isEscapable();
 }
 
-static bool usesFeatureIsolatedAny(Decl *decl) {
-  return usesTypeMatching(decl, [](Type type) {
-    if (auto fnType = type->getAs<AnyFunctionType>()) {
-      return fnType->getIsolation().isErased();
-    }
+static bool usesFeatureNonescapableAccessorOnTrivial(Decl *decl) {
+  if (!isa<VarDecl>(decl)) {
     return false;
-  });
+  }
+  auto var = cast<VarDecl>(decl);
+  if (!var->hasParsedAccessors()) {
+    return false;
+  }
+  // Check for properties that are both non-Copyable and non-Escapable
+  // (MutableSpan).
+  if (var->getTypeInContext()->isNoncopyable()
+      && !var->getTypeInContext()->isEscapable()) {
+    auto selfTy = var->getDeclContext()->getSelfTypeInContext();
+    // Consider 'self' trivial if it is BitwiseCopyable and Escapable
+    // (UnsafeMutableBufferPointer).
+    return selfTy->isBitwiseCopyable() && selfTy->isEscapable();
+  }
+  return false;
 }
 
+UNINTERESTING_FEATURE(DynamicActorIsolation)
+UNINTERESTING_FEATURE(NonfrozenEnumExhaustivity)
+UNINTERESTING_FEATURE(ClosureIsolation)
+UNINTERESTING_FEATURE(Extern)
+UNINTERESTING_FEATURE(ConsumeSelfInDeinit)
+
 static bool usesFeatureAddressableParameters(Decl *d) {
   if (d->getAttrs().hasAttribute<AddressableSelfAttr>()) {
     return true;
@@ -348,7 +296,7 @@ static ABIAttr *getABIAttr(Decl *decl) {
   return decl->getAttrs().getAttribute<ABIAttr>();
 }
 
-static bool usesFeatureABIAttribute(Decl *decl) {
+static bool usesFeatureABIAttributeSE0479(Decl *decl) {
   return getABIAttr(decl) != nullptr;
 }
 
@@ -366,88 +314,29 @@ static bool usesFeatureCompileTimeValues(Decl *decl) {
          decl->getAttrs().hasAttribute<ConstInitializedAttr>();
 }
 
-static bool usesFeatureClosureBodyMacro(Decl *decl) {
+static bool usesFeatureCompileTimeValuesPreview(Decl *decl) {
   return false;
 }
 
-static bool usesFeatureMemorySafetyAttributes(Decl *decl) {
-  if (decl->getAttrs().hasAttribute<SafeAttr>() ||
-      decl->getAttrs().hasAttribute<UnsafeAttr>())
-    return true;
-
-  IterableDeclContext *idc;
-  if (auto nominal = dyn_cast<NominalTypeDecl>(decl))
-    idc = nominal;
-  else if (auto ext = dyn_cast<ExtensionDecl>(decl))
-    idc = ext;
-  else
-    idc = nullptr;
-
-  // Look for an @unsafe conformance ascribed to this declaration.
-  if (idc) {
-    auto conformances = idc->getLocalConformances();
-    for (auto conformance : conformances) {
-      auto rootConformance = conformance->getRootConformance();
-      if (auto rootNormalConformance =
-              dyn_cast<NormalProtocolConformance>(rootConformance)) {
-        if (rootNormalConformance->getExplicitSafety() == ExplicitSafety::Unsafe)
-          return true;
-      }
-    }
-  }
-
+static bool usesFeatureClosureBodyMacro(Decl *decl) {
   return false;
 }
 
+static bool usesFeatureCDecl(Decl *decl) {
+  auto attr = decl->getAttrs().getAttribute<CDeclAttr>();
+  return attr && !attr->Underscored;
+}
+
 UNINTERESTING_FEATURE(StrictMemorySafety)
+UNINTERESTING_FEATURE(LibraryEvolution)
 UNINTERESTING_FEATURE(SafeInteropWrappers)
 UNINTERESTING_FEATURE(AssumeResilientCxxTypes)
 UNINTERESTING_FEATURE(ImportNonPublicCxxMembers)
-UNINTERESTING_FEATURE(CXXForeignReferenceTypeInitializers)
+UNINTERESTING_FEATURE(SuppressCXXForeignReferenceTypeInitializers)
+UNINTERESTING_FEATURE(WarnUnannotatedReturnOfCxxFrt)
 UNINTERESTING_FEATURE(CoroutineAccessorsUnwindOnCallerError)
 UNINTERESTING_FEATURE(AllowRuntimeSymbolDeclarations)
 
-static bool usesFeatureSwiftSettings(const Decl *decl) {
-  // We just need to guard `#SwiftSettings`.
-  auto *macro = dyn_cast<MacroDecl>(decl);
-  return macro && macro->isStdlibDecl() &&
-         macro->getMacroRoles().contains(MacroRole::Declaration) &&
-         macro->getBaseIdentifier().is("SwiftSettings");
-}
-
-bool swift::usesFeatureIsolatedDeinit(const Decl *decl) {
-  if (auto cd = dyn_cast<ClassDecl>(decl)) {
-    return cd->getFormalAccess() == AccessLevel::Open &&
-           usesFeatureIsolatedDeinit(cd->getDestructor());
-  } else if (auto dd = dyn_cast<DestructorDecl>(decl)) {
-    if (dd->hasExplicitIsolationAttribute()) {
-      return true;
-    }
-    if (auto superDD = dd->getSuperDeinit()) {
-      return usesFeatureIsolatedDeinit(superDD);
-    }
-    return false;
-  } else {
-    return false;
-  }
-}
-
-static bool usesFeatureValueGenerics(Decl *decl) {
-  auto genericContext = decl->getAsGenericContext();
-
-  if (!genericContext || !genericContext->getGenericParams())
-    return false;
-
-  for (auto param : genericContext->getGenericParams()->getParams()) {
-    if (param->isValue())
-      return true;
-
-    continue;
-  }
-
-  return false;
-}
-
 static bool usesFeatureCoroutineAccessors(Decl *decl) {
   auto accessorDeclUsesFeatureCoroutineAccessors = [](AccessorDecl *accessor) {
     return requiresFeatureCoroutineAccessors(accessor->getAccessorKind());
@@ -467,58 +356,100 @@ static bool usesFeatureCoroutineAccessors(Decl *decl) {
   }
 }
 
-static bool usesFeatureCustomAvailability(Decl *decl) {
-  // FIXME: [availability] Check whether @available attributes for custom
-  // domains are attached to the decl.
-  return false;
-}
+UNINTERESTING_FEATURE(GeneralizedIsSameMetaTypeBuiltin)
+UNINTERESTING_FEATURE(CustomAvailability)
 
-static bool usesFeatureBuiltinEmplaceTypedThrows(Decl *decl) {
-  // Callers of 'Builtin.emplace' should explicitly guard the usage with #if.
-  return false;
-}
+static bool usesFeatureAsyncExecutionBehaviorAttributes(Decl *decl) {
+  // Explicit `@concurrent` attribute on the declaration.
+  if (decl->getAttrs().hasAttribute<ConcurrentAttr>())
+    return true;
 
-static bool usesFeatureExecutionAttribute(Decl *decl) {
-  if (!DeclAttribute::canAttributeAppearOnDecl(DeclAttrKind::Execution, decl)) {
-    return false;
+  // Explicit `nonisolated(nonsending)` attribute on the declaration.
+  if (auto *nonisolated = decl->getAttrs().getAttribute<NonisolatedAttr>()) {
+    if (nonisolated->isNonSending())
+      return true;
   }
 
-  if (decl->getAttrs().hasAttribute<ExecutionAttr>())
-    return true;
-
-  auto hasExecutionAttr = [](TypeRepr *R) {
+  auto hasCallerIsolatedAttr = [](TypeRepr *R) {
     if (!R)
       return false;
 
     return R->findIf([](TypeRepr *repr) {
-      if (auto *AT = dyn_cast<AttributedTypeRepr>(repr)) {
-        return llvm::any_of(AT->getAttrs(), [](TypeOrCustomAttr attr) {
-          if (auto *TA = attr.dyn_cast<TypeAttribute *>()) {
-            return isa<ExecutionTypeAttr>(TA);
-          }
-          return false;
-        });
-      }
+      if (isa<CallerIsolatedTypeRepr>(repr))
+        return true;
+
+      // We don't check for @concurrent here because it's
+      // not printed in type positions since it indicates
+      // old "nonisolated" state.
+
       return false;
     });
   };
 
-  auto *VD = cast<ValueDecl>(decl);
+  auto *VD = dyn_cast<ValueDecl>(decl);
+  if (!VD)
+    return false;
+
+  // The declaration is going to be printed with `nonisolated(nonsending)`
+  // attribute.
+  if (getActorIsolation(VD).isCallerIsolationInheriting())
+    return true;
 
-  // Check if any parameters that have `@execution` attribute.
+  // Check if any parameters that have `nonisolated(nonsending)` attribute.
   if (auto *PL = VD->getParameterList()) {
-    for (auto *P : *PL) {
-      if (hasExecutionAttr(P->getTypeRepr()))
-        return true;
-    }
+    if (llvm::any_of(*PL, [&](const ParamDecl *P) {
+          return hasCallerIsolatedAttr(P->getTypeRepr());
+        }))
+      return true;
   }
 
-  if (hasExecutionAttr(VD->getResultTypeRepr()))
+  // Check if result type has explicit `nonisolated(nonsending)` attribute.
+  if (hasCallerIsolatedAttr(VD->getResultTypeRepr()))
     return true;
 
   return false;
 }
 
+static bool usesFeatureNonexhaustiveAttribute(Decl *decl) {
+  return decl->getAttrs().hasAttribute<NonexhaustiveAttr>();
+}
+
+static bool usesFeatureAlwaysInheritActorContext(Decl *decl) {
+  auto *VD = dyn_cast<ValueDecl>(decl);
+  if (!VD)
+    return false;
+
+  if (auto *PL = VD->getParameterList()) {
+    return llvm::any_of(*PL, [&](const ParamDecl *P) {
+      auto *attr = P->getAttrs().getAttribute<InheritActorContextAttr>();
+      return attr && attr->isAlways();
+    });
+  }
+
+  return false;
+}
+
+static bool usesFeatureDefaultIsolationPerFile(Decl *D) {
+  return isa<UsingDecl>(D);
+}
+
+UNINTERESTING_FEATURE(BuiltinSelect)
+UNINTERESTING_FEATURE(BuiltinInterleave)
+UNINTERESTING_FEATURE(BuiltinVectorsExternC)
+UNINTERESTING_FEATURE(AddressOfProperty2)
+UNINTERESTING_FEATURE(ImmutableWeakCaptures)
+// Ignore borrow and mutate accessors until it is used in the standard library.
+UNINTERESTING_FEATURE(BorrowAndMutateAccessors)
+
+static bool usesFeatureInlineAlways(Decl *decl) {
+  if (auto *inlineAttr = decl->getAttrs().getAttribute<InlineAttr>()) {
+    return inlineAttr->getKind() == InlineKind::Always;
+  }
+  return false;
+}
+
+UNINTERESTING_FEATURE(SwiftRuntimeAvailability)
+
 // ----------------------------------------------------------------------------
 // MARK: - FeatureSet
 // ----------------------------------------------------------------------------
@@ -530,7 +461,7 @@ void FeatureSet::collectRequiredFeature(Feature feature,
 
 void FeatureSet::collectSuppressibleFeature(Feature feature,
                                             InsertOrRemove operation) {
-  suppressible.insertOrRemove(numFeatures() - size_t(feature),
+  suppressible.insertOrRemove(Feature::getNumFeatures() - size_t(feature),
                               operation == Insert);
 }
 
@@ -551,6 +482,11 @@ static bool hasFeatureSuppressionAttribute(Decl *decl, StringRef featureName,
   return false;
 }
 
+// These functions are only used when there suppressible language features
+// defined, so suppress warnings about them being unused to avoid spam when
+// there are none.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunused"
 static bool disallowFeatureSuppression(StringRef featureName, Decl *decl) {
   return hasFeatureSuppressionAttribute(decl, featureName, true);
 }
@@ -558,6 +494,7 @@ static bool disallowFeatureSuppression(StringRef featureName, Decl *decl) {
 static bool allowFeatureSuppression(StringRef featureName, Decl *decl) {
   return hasFeatureSuppressionAttribute(decl, featureName, false);
 }
+#pragma clang diagnostic pop
 
 /// Go through all the features used by the given declaration and
 /// either add or remove them to this set.
@@ -604,8 +541,12 @@ FeatureSet swift::getUniqueFeaturesUsed(Decl *decl) {
   // Remove all the features used by all enclosing declarations.
   Decl *enclosingDecl = decl;
   while (!features.empty()) {
+    // If we were in an @abi attribute, collect from the API counterpart.
+    auto abiRole = ABIRoleInfo(enclosingDecl);
+    if (!abiRole.providesAPI() && abiRole.getCounterpart())
+      enclosingDecl = abiRole.getCounterpart();
     // Find the next outermost enclosing declaration.
-    if (auto accessor = dyn_cast<AccessorDecl>(enclosingDecl))
+    else if (auto accessor = dyn_cast<AccessorDecl>(enclosingDecl))
       enclosingDecl = accessor->getStorage();
     else
       enclosingDecl = enclosingDecl->getDeclContext()->getAsDecl();
diff --git a/lib/AST/FeatureSet.h b/lib/AST/FeatureSet.h
index 67fa5473097ca..09bada2053fd7 100644
--- a/lib/AST/FeatureSet.h
+++ b/lib/AST/FeatureSet.h
@@ -19,7 +19,8 @@
 
 namespace swift {
 
-using BasicFeatureSet = FixedBitSet<numFeatures(), Feature>;
+using BasicFeatureSet =
+    FixedBitSet<Feature::getNumFeatures(), Feature::InnerKind>;
 
 class FeatureSet {
   BasicFeatureSet required;
@@ -30,7 +31,7 @@ class FeatureSet {
   // This is the easiest way of letting us iterate from largest to
   // smallest, i.e. from the newest to the oldest feature, which is
   // the order in which we need to emit #if clauses.
-  using SuppressibleFeatureSet = FixedBitSet<numFeatures(), size_t>;
+  using SuppressibleFeatureSet = FixedBitSet<Feature::getNumFeatures(), size_t>;
   SuppressibleFeatureSet suppressible;
 
 public:
@@ -42,7 +43,7 @@ class FeatureSet {
 
   public:
     bool empty() const { return i == e; }
-    Feature next() { return Feature(numFeatures() - *i++); }
+    Feature next() { return Feature(Feature::getNumFeatures() - *i++); }
   };
 
   bool empty() const { return required.empty() && suppressible.empty(); }
diff --git a/lib/AST/FrontendSourceFileDepGraphFactory.cpp b/lib/AST/FrontendSourceFileDepGraphFactory.cpp
index 3b4c88d4158ba..2bf699be7f714 100644
--- a/lib/AST/FrontendSourceFileDepGraphFactory.cpp
+++ b/lib/AST/FrontendSourceFileDepGraphFactory.cpp
@@ -221,6 +221,7 @@ StringRef DependencyKey::Builder::getTopLevelName(const Decl *decl) {
   case DeclKind::MissingMember:
   case DeclKind::Module:
   case DeclKind::MacroExpansion:
+  case DeclKind::Using:
     return "";
   }
 
@@ -241,7 +242,7 @@ bool fine_grained_dependencies::withReferenceDependencies(
         ModuleDepGraphFactory(backend, MD, alsoEmitDotFile).construct();
     return cont(std::move(g));
   } else {
-    auto *SF = MSF.get<const SourceFile *>();
+    auto *SF = cast<const SourceFile *>(MSF);
     SourceFileDepGraph g =
         FrontendSourceFileDepGraphFactory(SF, backend, outputPath, depTracker,
                                           alsoEmitDotFile)
diff --git a/lib/AST/GenericEnvironment.cpp b/lib/AST/GenericEnvironment.cpp
index 915c19f5ea34e..f3633002506b8 100644
--- a/lib/AST/GenericEnvironment.cpp
+++ b/lib/AST/GenericEnvironment.cpp
@@ -31,8 +31,8 @@ size_t GenericEnvironment::numTrailingObjects(
   case Kind::Primary:
     return 0;
 
-  case Kind::OpenedExistential:
-  case Kind::OpenedElement:
+  case Kind::Existential:
+  case Kind::Element:
   case Kind::Opaque:
     return 1;
   }
@@ -42,8 +42,8 @@ size_t GenericEnvironment::numTrailingObjects(
     OverloadToken<OpaqueEnvironmentData>) const {
   switch (getKind()) {
   case Kind::Primary:
-  case Kind::OpenedExistential:
-  case Kind::OpenedElement:
+  case Kind::Existential:
+  case Kind::Element:
     return 0;
 
   case Kind::Opaque:
@@ -52,34 +52,34 @@ size_t GenericEnvironment::numTrailingObjects(
 }
 
 size_t GenericEnvironment::numTrailingObjects(
-    OverloadToken<OpenedExistentialEnvironmentData>) const {
+    OverloadToken<ExistentialEnvironmentData>) const {
   switch (getKind()) {
   case Kind::Primary:
   case Kind::Opaque:
-  case Kind::OpenedElement:
+  case Kind::Element:
     return 0;
 
-  case Kind::OpenedExistential:
+  case Kind::Existential:
     return 1;
   }
 }
 
 size_t GenericEnvironment::numTrailingObjects(
-    OverloadToken<OpenedElementEnvironmentData>) const {
+    OverloadToken<ElementEnvironmentData>) const {
   switch (getKind()) {
   case Kind::Primary:
   case Kind::Opaque:
-  case Kind::OpenedExistential:
+  case Kind::Existential:
     return 0;
 
-  case Kind::OpenedElement:
+  case Kind::Element:
     return 1;
   }
 }
 
 size_t GenericEnvironment::numTrailingObjects(OverloadToken<Type>) const {
   return getGenericParams().size()
-       + (getKind() == Kind::OpenedElement ? getNumOpenedPackParams() : 0);
+       + (getKind() == Kind::Element ? getNumOpenedPackParams() : 0);
 }
 
 /// Retrieve the array containing the context types associated with the
@@ -99,7 +99,7 @@ ArrayRef<Type> GenericEnvironment::getContextTypes() const {
 }
 
 unsigned GenericEnvironment::getNumOpenedPackParams() const {
-  assert(getKind() == Kind::OpenedElement);
+  assert(getKind() == Kind::Element);
   return getGenericSignature().getInnermostGenericParams().size();
 }
 
@@ -130,24 +130,24 @@ OpaqueTypeDecl *GenericEnvironment::getOpaqueTypeDecl() const {
 
 CanGenericTypeParamType
 GenericEnvironment::getOpenedElementShapeClass() const {
-  assert(getKind() == Kind::OpenedElement);
-  auto environmentData = getTrailingObjects<OpenedElementEnvironmentData>();
+  assert(getKind() == Kind::Element);
+  auto environmentData = getTrailingObjects<ElementEnvironmentData>();
   return environmentData->shapeClass;
 }
 
 Type GenericEnvironment::getOpenedExistentialType() const {
-  assert(getKind() == Kind::OpenedExistential);
-  return getTrailingObjects<OpenedExistentialEnvironmentData>()->existential;
+  assert(getKind() == Kind::Existential);
+  return getTrailingObjects<ExistentialEnvironmentData>()->existential;
 }
 
 UUID GenericEnvironment::getOpenedExistentialUUID() const {
-  assert(getKind() == Kind::OpenedExistential);
-  return getTrailingObjects<OpenedExistentialEnvironmentData>()->uuid;
+  assert(getKind() == Kind::Existential);
+  return getTrailingObjects<ExistentialEnvironmentData>()->uuid;
 }
 
 UUID GenericEnvironment::getOpenedElementUUID() const {
-  assert(getKind() == Kind::OpenedElement);
-  return getTrailingObjects<OpenedElementEnvironmentData>()->uuid;
+  assert(getKind() == Kind::Element);
+  return getTrailingObjects<ElementEnvironmentData>()->uuid;
 }
 
 void GenericEnvironment::forEachPackElementArchetype(
@@ -203,22 +203,21 @@ void GenericEnvironment::forEachPackElementBinding(
   assert(elementIt == packElements.end());
 }
 
-GenericEnvironment::GenericEnvironment(GenericSignature signature)
-  : SignatureAndKind(signature, Kind::Primary)
-{
+GenericEnvironment::GenericEnvironment(GenericSignature sig)
+  : sig(sig), kind(Kind::Primary), canonical(true) {
   // Clear out the memory that holds the context types.
   std::uninitialized_fill(getContextTypes().begin(), getContextTypes().end(),
                           Type());
 }
 
 GenericEnvironment::GenericEnvironment(
-    GenericSignature signature,
+    GenericSignature sig,
     Type existential, SubstitutionMap subs, UUID uuid)
-  : SignatureAndKind(signature, Kind::OpenedExistential)
-{
+  : sig(sig), kind(Kind::Existential), canonical(subs.isCanonical()) {
+  ASSERT(canonical);
   *getTrailingObjects<SubstitutionMap>() = subs;
-  new (getTrailingObjects<OpenedExistentialEnvironmentData>())
-    OpenedExistentialEnvironmentData{ existential, uuid };
+  new (getTrailingObjects<ExistentialEnvironmentData>())
+    ExistentialEnvironmentData{ existential, uuid };
 
   // Clear out the memory that holds the context types.
   std::uninitialized_fill(getContextTypes().begin(), getContextTypes().end(),
@@ -226,9 +225,8 @@ GenericEnvironment::GenericEnvironment(
 }
 
 GenericEnvironment::GenericEnvironment(
-      GenericSignature signature, OpaqueTypeDecl *opaque, SubstitutionMap subs)
-  : SignatureAndKind(signature, Kind::Opaque)
-{
+      GenericSignature sig, OpaqueTypeDecl *opaque, SubstitutionMap subs)
+  : sig(sig), kind(Kind::Opaque), canonical(subs.isCanonical()) {
   *getTrailingObjects<SubstitutionMap>() = subs;
   new (getTrailingObjects<OpaqueEnvironmentData>())
     OpaqueEnvironmentData{opaque};
@@ -238,15 +236,15 @@ GenericEnvironment::GenericEnvironment(
                           Type());
 }
 
-GenericEnvironment::GenericEnvironment(GenericSignature signature,
+GenericEnvironment::GenericEnvironment(GenericSignature sig,
                                        UUID uuid,
                                        CanGenericTypeParamType shapeClass,
                                        SubstitutionMap outerSubs)
-  : SignatureAndKind(signature, Kind::OpenedElement)
-{
+  : sig(sig), kind(Kind::Element), canonical(true) {
+  // FIXME: ASSERT(outerSubs.isCanonical());
   *getTrailingObjects<SubstitutionMap>() = outerSubs;
-  new (getTrailingObjects<OpenedElementEnvironmentData>())
-    OpenedElementEnvironmentData{uuid, shapeClass};
+  new (getTrailingObjects<ElementEnvironmentData>())
+    ElementEnvironmentData{uuid, shapeClass};
 
   // Clear out the memory that holds the context types.
   std::uninitialized_fill(getContextTypes().begin(), getContextTypes().end(),
@@ -255,9 +253,9 @@ GenericEnvironment::GenericEnvironment(GenericSignature signature,
   // Fill in the array of opened pack parameters.
   auto openedPacksBuffer = getOpenedPackParams();
   unsigned i = 0;
-  for (auto param : signature.getGenericParams()) {
+  for (auto param : sig.getGenericParams()) {
     if (!param->isParameterPack()) continue;
-    if (!signature->haveSameShape(param, shapeClass)) continue;
+    if (!sig->haveSameShape(param, shapeClass)) continue;
     openedPacksBuffer[i++] = param;
   }
   assert(i == openedPacksBuffer.size());
@@ -314,12 +312,16 @@ GenericEnvironment::maybeApplyOuterContextSubstitutions(Type type) const {
   case Kind::Primary:
     return type;
 
-  case Kind::OpenedExistential:
-  case Kind::OpenedElement:
+  case Kind::Existential:
+  case Kind::Element:
   case Kind::Opaque: {
-    OuterSubstitutions replacer{
-        getOuterSubstitutions(), getGenericSignature()->getMaxDepth()};
-    return type.subst(replacer, replacer);
+    if (auto subs = getOuterSubstitutions()) {
+      OuterSubstitutions replacer{subs,
+                                  getGenericSignature()->getMaxDepth()};
+      return type.subst(replacer, replacer);
+    }
+
+    return type;
   }
   }
 }
@@ -349,9 +351,9 @@ Type MapTypeOutOfContext::operator()(SubstitutableType *type) const {
 Type TypeBase::mapTypeOutOfContext() {
   assert(!hasTypeParameter() && "already have an interface type");
   return Type(this).subst(MapTypeOutOfContext(),
-    MakeAbstractConformanceForGenericType(),
-    SubstFlags::PreservePackExpansionLevel |
-    SubstFlags::SubstitutePrimaryArchetypes);
+                          LookUpConformanceInModule(),
+                          SubstFlags::PreservePackExpansionLevel |
+                          SubstFlags::SubstitutePrimaryArchetypes);
 }
 
 auto GenericEnvironment::getOrCreateNestedTypeStorage() -> NestedTypeStorage & {
@@ -442,7 +444,7 @@ GenericEnvironment::getOrCreateArchetypeFromInterfaceType(Type depType) {
     break;
   }
 
-  case Kind::OpenedExistential: {
+  case Kind::Existential: {
     if (rootGP->getDepth() < genericSig->getMaxDepth()) {
       result = maybeApplyOuterContextSubstitutions(reducedType);
       break;
@@ -475,7 +477,7 @@ GenericEnvironment::getOrCreateArchetypeFromInterfaceType(Type depType) {
     break;
   }
 
-  case Kind::OpenedElement: {
+  case Kind::Element: {
     if (rootGP->getDepth() < genericSig->getMaxDepth()) {
       result = maybeApplyOuterContextSubstitutions(reducedType);
       break;
@@ -606,7 +608,7 @@ struct FindElementArchetypeForOpenedPackParam {
 /// does not apply outer substitutions, which might not be what you expect.
 Type
 GenericEnvironment::mapContextualPackTypeIntoElementContext(Type type) const {
-  assert(getKind() == Kind::OpenedElement);
+  assert(getKind() == Kind::Element);
   assert(!type->hasTypeParameter() && "expected contextual type");
 
   if (!type->hasPackArchetype()) return type;
@@ -638,7 +640,7 @@ GenericEnvironment::mapContextualPackTypeIntoElementContext(CanType type) const
 /// substitutions, so it behaves like mapTypeIntoContext() in that respect.
 Type
 GenericEnvironment::mapPackTypeIntoElementContext(Type type) const {
-  assert(getKind() == Kind::OpenedElement);
+  assert(getKind() == Kind::Element);
   assert(!type->hasPackArchetype());
 
   if (!type->hasParameterPack()) return type;
@@ -680,7 +682,7 @@ GenericEnvironment::mapElementTypeIntoPackContext(Type type) const {
 
       return archetype->getInterfaceType();
     },
-    MakeAbstractConformanceForGenericType(),
+    LookUpConformanceInModule(),
     SubstFlags::PreservePackExpansionLevel |
     SubstFlags::SubstitutePrimaryArchetypes |
     SubstFlags::SubstituteLocalArchetypes);
@@ -745,33 +747,12 @@ Type BuildForwardingSubstitutions::operator()(SubstitutableType *type) const {
   return Type();
 }
 
-SubstitutionMap GenericEnvironment::getForwardingSubstitutionMap() const {
+SubstitutionMap
+GenericEnvironment::getForwardingSubstitutionMap() const {
   auto genericSig = getGenericSignature();
   return SubstitutionMap::get(genericSig,
                               BuildForwardingSubstitutions(this),
-                              MakeAbstractConformanceForGenericType());
-}
-
-std::pair<Type, ProtocolConformanceRef>
-GenericEnvironment::mapConformanceRefIntoContext(GenericEnvironment *genericEnv,
-                                           Type conformingType,
-                                           ProtocolConformanceRef conformance) {
-  if (!genericEnv)
-    return {conformingType, conformance};
-  
-  return genericEnv->mapConformanceRefIntoContext(conformingType, conformance);
-}
-
-std::pair<Type, ProtocolConformanceRef>
-GenericEnvironment::mapConformanceRefIntoContext(
-                                     Type conformingInterfaceType,
-                                     ProtocolConformanceRef conformance) const {
-  auto contextConformance = conformance.subst(conformingInterfaceType,
-    QueryInterfaceTypeSubstitutions(this),
-    LookUpConformanceInModule());
-  
-  auto contextType = mapTypeIntoContext(conformingInterfaceType);
-  return {contextType, contextConformance};
+                              LookUpConformanceInModule());
 }
 
 OpenedElementContext
diff --git a/lib/AST/GenericParamList.cpp b/lib/AST/GenericParamList.cpp
index 7ca5ffbb42f36..3dbfe884992d5 100644
--- a/lib/AST/GenericParamList.cpp
+++ b/lib/AST/GenericParamList.cpp
@@ -39,8 +39,7 @@ GenericParamList::GenericParamList(SourceLoc LAngleLoc,
     WhereLoc(WhereLoc), Requirements(Requirements),
     OuterParameters(nullptr)
 {
-  std::uninitialized_copy(Params.begin(), Params.end(),
-                          getTrailingObjects<GenericTypeParamDecl *>());
+  std::uninitialized_copy(Params.begin(), Params.end(), getTrailingObjects());
 }
 
 GenericParamList *
@@ -123,7 +122,7 @@ TrailingWhereClause::TrailingWhereClause(
     NumRequirements(requirements.size())
 {
   std::uninitialized_copy(requirements.begin(), requirements.end(),
-                          getTrailingObjects<RequirementRepr>());
+                          getTrailingObjects());
 }
 
 TrailingWhereClause *TrailingWhereClause::create(
diff --git a/lib/AST/GenericSignature.cpp b/lib/AST/GenericSignature.cpp
index a0b672e68473b..07d87aa04b8fc 100644
--- a/lib/AST/GenericSignature.cpp
+++ b/lib/AST/GenericSignature.cpp
@@ -246,7 +246,7 @@ bool GenericSignatureImpl::isEqual(GenericSignature Other) const {
 }
 
 bool GenericSignatureImpl::isCanonical() const {
-  if (CanonicalSignatureOrASTContext.is<ASTContext *>())
+  if (isa<ASTContext *>(CanonicalSignatureOrASTContext))
     return true;
   return getCanonicalSignature().getPointer() == this;
 }
@@ -300,12 +300,12 @@ CanGenericSignature GenericSignatureImpl::getCanonicalSignature() const {
 
   // A stored ASTContext indicates that this is the canonical
   // signature.
-  if (CanonicalSignatureOrASTContext.is<ASTContext *>())
+  if (isa<ASTContext *>(CanonicalSignatureOrASTContext))
     return CanGenericSignature(this);
 
   // Otherwise, return the stored canonical signature.
   return CanGenericSignature(
-      CanonicalSignatureOrASTContext.get<const GenericSignatureImpl *>());
+      cast<const GenericSignatureImpl *>(CanonicalSignatureOrASTContext));
 }
 
 GenericEnvironment *GenericSignature::getGenericEnvironment() const {
@@ -371,6 +371,44 @@ bool GenericSignatureImpl::requiresProtocol(Type type,
   return getRequirementMachine()->requiresProtocol(type, proto);
 }
 
+std::optional<std::pair<Type, ProtocolDecl *>>
+GenericSignatureImpl::prohibitsIsolatedConformance(Type type) const {
+  type = getReducedType(type);
+
+  if (!type->isTypeParameter())
+    return std::nullopt;
+
+  // An isolated conformance cannot be used in a context where the type
+  // parameter can escape the isolation domain in which the conformance
+  // was formed. To establish this, we look for Sendable or SendableMetatype
+  // requirements on the type parameter itself.
+  ASTContext &ctx = type->getASTContext();
+  auto sendableProto = ctx.getProtocol(KnownProtocolKind::Sendable);
+  auto sendableMetatypeProto =
+      ctx.getProtocol(KnownProtocolKind::SendableMetatype);
+
+  // Check for a conformance requirement to SendableMetatype, which is
+  // implied by Sendable.
+  if (sendableMetatypeProto && requiresProtocol(type, sendableMetatypeProto)) {
+    // Check for a conformance requirement to Sendable and return that if
+    // it exists, because it's more recognizable and specific.
+    if (sendableProto && requiresProtocol(type, sendableProto))
+      return std::make_pair(type, sendableProto);
+
+    return std::make_pair(type, sendableMetatypeProto);
+  }
+
+  // If this is a nested type, also check whether the parent type conforms to
+  // SendableMetatype, because one can derive this type from the parent type.
+  // FIXME: This is not a complete check, because there are other ways in which
+  // one might be able to derive this type. This needs to determine whether
+  // there is any path from a SendableMetatype-conforming type to this type.
+  if (auto depMemTy = type->getAs<DependentMemberType>())
+    return prohibitsIsolatedConformance(depMemTy->getBase());
+
+  return std::nullopt;
+}
+
 /// Determine whether the given dependent type is equal to a concrete type.
 bool GenericSignatureImpl::isConcreteType(Type type) const {
   assert(type->isTypeParameter() && "Expected a type parameter");
@@ -603,7 +641,7 @@ SubstitutionMap GenericSignatureImpl::getIdentitySubstitutionMap() const {
         return param;
       return PackType::getSingletonPackExpansion(param);
     },
-    MakeAbstractConformanceForGenericType());
+    LookUpConformanceInModule());
 }
 
 GenericTypeParamType *GenericSignatureImpl::getSugaredType(
@@ -793,8 +831,7 @@ int swift::compareAssociatedTypes(AssociatedTypeDecl *assocType1,
   return 0;
 }
 
-/// Canonical ordering for type parameters.
-int swift::compareDependentTypes(Type type1, Type type2) {
+static int compareDependentTypesRec(Type type1, Type type2) {
   // Fast-path check for equality.
   if (type1->isEqual(type2)) return 0;
 
@@ -815,7 +852,7 @@ int swift::compareDependentTypes(Type type1, Type type2) {
 
   // - by base, so t_0_n.`P.T` < t_1_m.`P.T`
   if (int compareBases =
-        compareDependentTypes(depMemTy1->getBase(), depMemTy2->getBase()))
+        compareDependentTypesRec(depMemTy1->getBase(), depMemTy2->getBase()))
     return compareBases;
 
   // - by name, so t_n_m.`P.T` < t_n_m.`P.U`
@@ -831,6 +868,17 @@ int swift::compareDependentTypes(Type type1, Type type2) {
   return 0;
 }
 
+/// Canonical ordering for type parameters.
+int swift::compareDependentTypes(Type type1, Type type2) {
+  auto *root1 = type1->getRootGenericParam();
+  auto *root2 = type2->getRootGenericParam();
+  if (root1->getWeight() != root2->getWeight()) {
+    return root2->getWeight() ? -1 : +1;
+  }
+
+  return compareDependentTypesRec(type1, type2);
+}
+
 #pragma mark Generic signature verification
 
 void GenericSignature::verify() const {
@@ -838,15 +886,18 @@ void GenericSignature::verify() const {
 }
 
 void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
-  auto dumpAndAbort = [&]() {
-    llvm::errs() << "All requirements:\n";
-    for (auto reqt : reqts) {
-      reqt.dump(llvm::errs());
-      llvm::errs() << "\n";
-    }
-    getPointer()->getRequirementMachine()->dump(llvm::errs());
-    abort();
-  };
+  auto dumpAndAbort =
+      [&](llvm::function_ref<void(llvm::raw_ostream &)> message) {
+        ABORT([&](auto &out) {
+          message(out);
+          out << "\nAll requirements:\n";
+          for (auto reqt : reqts) {
+            reqt.dump(out);
+            out << "\n";
+          }
+          getPointer()->getRequirementMachine()->dump(out);
+        });
+      };
 
   auto canSig = getCanonicalSignature();
 
@@ -865,17 +916,17 @@ void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
     // Left-hand side must be a canonical type parameter.
     if (reqt.getKind() != RequirementKind::SameType) {
       if (!reqt.getFirstType()->isTypeParameter()) {
-        llvm::errs() << "Left-hand side must be a type parameter: ";
-        reqt.dump(llvm::errs());
-        llvm::errs() << "\n";
-        dumpAndAbort();
+        dumpAndAbort([&](auto &out) {
+          out << "Left-hand side must be a type parameter: ";
+          reqt.dump(out);
+        });
       }
 
       if (!canSig->isReducedType(reqt.getFirstType())) {
-        llvm::errs() << "Left-hand side is not reduced: ";
-        reqt.dump(llvm::errs());
-        llvm::errs() << "\n";
-        dumpAndAbort();
+        dumpAndAbort([&](auto &out) {
+          out << "Left-hand side is not reduced: ";
+          reqt.dump(out);
+        });
       }
     }
 
@@ -883,40 +934,40 @@ void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
     switch (reqt.getKind()) {
     case RequirementKind::SameShape:
       if (!reqt.getFirstType()->is<GenericTypeParamType>()) {
-        llvm::errs() << "Left hand side is not a generic parameter: ";
-        reqt.dump(llvm::errs());
-        llvm::errs() << "\n";
-        dumpAndAbort();
+        dumpAndAbort([&](auto &out) {
+          out << "Left hand side is not a generic parameter: ";
+          reqt.dump(out);
+        });
       }
 
       if (!reqt.getFirstType()->isRootParameterPack()) {
-        llvm::errs() << "Left hand side is not a parameter pack: ";
-        reqt.dump(llvm::errs());
-        llvm::errs() << "\n";
-        dumpAndAbort();
+        dumpAndAbort([&](auto &out) {
+          out << "Left hand side is not a parameter pack: ";
+          reqt.dump(out);
+        });
       }
 
       if (!reqt.getSecondType()->is<GenericTypeParamType>()) {
-        llvm::errs() << "Right hand side is not a generic parameter: ";
-        reqt.dump(llvm::errs());
-        llvm::errs() << "\n";
-        dumpAndAbort();
+        dumpAndAbort([&](auto &out) {
+          out << "Right hand side is not a generic parameter: ";
+          reqt.dump(out);
+        });
       }
 
       if (!reqt.getSecondType()->isRootParameterPack()) {
-        llvm::errs() << "Right hand side is not a parameter pack: ";
-        reqt.dump(llvm::errs());
-        llvm::errs() << "\n";
-        dumpAndAbort();
+        dumpAndAbort([&](auto &out) {
+          out << "Right hand side is not a parameter pack: ";
+          reqt.dump(out);
+        });
       }
 
       break;
     case RequirementKind::Superclass:
       if (!canSig->isReducedType(reqt.getSecondType())) {
-        llvm::errs() << "Right-hand side is not reduced: ";
-        reqt.dump(llvm::errs());
-        llvm::errs() << "\n";
-        dumpAndAbort();
+        dumpAndAbort([&](auto &out) {
+          out << "Right-hand side is not reduced: ";
+          reqt.dump(out);
+        });
       }
       break;
 
@@ -939,53 +990,53 @@ void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
       auto &component = sameTypeComponents[canType];
 
       if (!hasReducedOrConcreteParent(firstType)) {
-        llvm::errs() << "Left hand side does not have a reduced parent: ";
-        reqt.dump(llvm::errs());
-        llvm::errs() << "\n";
-        dumpAndAbort();
+        dumpAndAbort([&](auto &out) {
+          out << "Left hand side does not have a reduced parent: ";
+          reqt.dump(out);
+        });
       }
 
       if (reqt.getSecondType()->isTypeParameter()) {
         if (!hasReducedOrConcreteParent(secondType)) {
-          llvm::errs() << "Right hand side does not have a reduced parent: ";
-          reqt.dump(llvm::errs());
-          llvm::errs() << "\n";
-          dumpAndAbort();
+          dumpAndAbort([&](auto &out) {
+            out << "Right hand side does not have a reduced parent: ";
+            reqt.dump(out);
+          });
         }
 
         if (compareDependentTypes(firstType, secondType) >= 0) {
-          llvm::errs() << "Out-of-order type parameters: ";
-          reqt.dump(llvm::errs());
-          llvm::errs() << "\n";
-          dumpAndAbort();
+          dumpAndAbort([&](auto &out) {
+            out << "Out-of-order type parameters: ";
+            reqt.dump(out);
+          });
         }
 
         if (component.empty()) {
           component.push_back(firstType);
         } else if (!component.back()->isEqual(firstType)) {
-          llvm::errs() << "Same-type requirement within an equiv. class "
-                       << "is out-of-order: ";
-          reqt.dump(llvm::errs());
-          llvm::errs() << "\n";
-          dumpAndAbort();
+          dumpAndAbort([&](auto &out) {
+            out << "Same-type requirement within an equiv. class "
+                << "is out-of-order: ";
+            reqt.dump(out);
+          });
         }
 
         component.push_back(secondType);
       } else {
         if (!canSig->isReducedType(secondType)) {
-          llvm::errs() << "Right hand side is not reduced: ";
-          reqt.dump(llvm::errs());
-          llvm::errs() << "\n";
-          dumpAndAbort();
+          dumpAndAbort([&](auto &out) {
+            out << "Right hand side is not reduced: ";
+            reqt.dump(out);
+          });
         }
 
         if (component.empty()) {
           component.push_back(secondType);
         } else if (!component.back()->isEqual(secondType)) {
-          llvm::errs() << "Inconsistent concrete requirement in equiv. class: ";
-          reqt.dump(llvm::errs());
-          llvm::errs() << "\n";
-          dumpAndAbort();
+          dumpAndAbort([&](auto &out) {
+            out << "Inconsistent concrete requirement in equiv. class: ";
+            reqt.dump(out);
+          });
         }
       }
       break;
@@ -1006,10 +1057,10 @@ void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
     int compareLHS =
       compareDependentTypes(prevReqt.getFirstType(), reqt.getFirstType());
     if (compareLHS > 0) {
-      llvm::errs() << "Out-of-order left-hand side: ";
-      reqt.dump(llvm::errs());
-      llvm::errs() << "\n";
-      dumpAndAbort();
+      dumpAndAbort([&](auto &out) {
+        out << "Out-of-order left-hand side: ";
+        reqt.dump(out);
+      });
     }
 
     // If we have a concrete same-type requirement, we shouldn't have any
@@ -1017,19 +1068,19 @@ void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
     if (reqt.getKind() == RequirementKind::SameType &&
         !reqt.getSecondType()->isTypeParameter()) {
       if (compareLHS >= 0) {
-        llvm::errs() << "Concrete subject type should not have "
-                     << "any other requirements: ";
-        reqt.dump(llvm::errs());
-        llvm::errs() << "\n";
-        dumpAndAbort();
+        dumpAndAbort([&](auto &out) {
+          out << "Concrete subject type should not have "
+              << "any other requirements: ";
+          reqt.dump(out);
+        });
       }
     }
 
     if (prevReqt.compare(reqt) >= 0) {
-      llvm::errs() << "Out-of-order requirement: ";
-      reqt.dump(llvm::errs());
-      llvm::errs() << "\n";
-      dumpAndAbort();
+      dumpAndAbort([&](auto &out) {
+        out << "Out-of-order requirement: ";
+        reqt.dump(out);
+      });
     }
   }
 
@@ -1044,19 +1095,21 @@ void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
     ProtocolType::canonicalizeProtocols(canonicalProtos);
 
     if (protos.size() != canonicalProtos.size()) {
-      llvm::errs() << "Redundant conformance requirements in signature "
-                   << *this << ":\n";
-      llvm::errs() << "Ours:\n";
-      for (auto *proto : protos)
-        llvm::errs() << "- " << proto->getName() << "\n";
-      llvm::errs() << "Theirs:\n";
-      for (auto *proto : canonicalProtos)
-        llvm::errs() << "- " << proto->getName() << "\n";
-      dumpAndAbort();
+      dumpAndAbort([&](auto &out) {
+        out << "Redundant conformance requirements in signature " << *this
+            << ":\n";
+        out << "Ours:\n";
+        for (auto *proto : protos)
+          out << "- " << proto->getName() << "\n";
+        out << "Theirs:\n";
+        for (auto *proto : canonicalProtos)
+          out << "- " << proto->getName();
+      });
     }
     if (!std::equal(protos.begin(), protos.end(), canonicalProtos.begin())) {
-      llvm::errs() << "Out-of-order conformance requirements\n";
-      dumpAndAbort();
+      dumpAndAbort([&](auto &out) {
+        out << "Out-of-order conformance requirements";
+      });
     }
   }
 
@@ -1064,11 +1117,11 @@ void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
   for (const auto &pair : sameTypeComponents) {
     if (pair.second.front()->isTypeParameter() &&
         !canSig->isReducedType(pair.second.front())) {
-      llvm::errs() << "Abstract same-type requirement involving concrete types\n";
-      llvm::errs() << "Reduced type: " << pair.first << "\n";
-      llvm::errs() << "Left hand side of first requirement: "
-                   << pair.second.front() << "\n";
-      dumpAndAbort();
+      dumpAndAbort([&](auto &out) {
+        out << "Abstract same-type requirement involving concrete types\n";
+        out << "Reduced type: " << pair.first << "\n";
+        out << "Left hand side of first requirement: " << pair.second.front();
+      });
     }
   }
 }
@@ -1114,10 +1167,6 @@ static Requirement stripBoundDependentMemberTypes(Requirement req) {
 
 void swift::validateGenericSignature(ASTContext &context,
                                      GenericSignature sig) {
-  llvm::errs() << "Validating generic signature: ";
-  sig->print(llvm::errs());
-  llvm::errs() << "\n";
-
   // Try building a new signature having the same requirements.
   SmallVector<GenericTypeParamType *, 2> genericParams;
   for (auto *genericParam :  sig.getGenericParams())
@@ -1130,15 +1179,11 @@ void swift::validateGenericSignature(ASTContext &context,
   {
     PrettyStackTraceGenericSignature debugStack("verifying", sig);
 
-    auto newSigWithError = evaluateOrDefault(
-        context.evaluator,
-        AbstractGenericSignatureRequest{
-            nullptr,
-            genericParams,
-            requirements,
-            /*allowInverses=*/false},
-        GenericSignatureWithError());
-
+    auto newSigWithError = buildGenericSignatureWithError(context,
+                                                      GenericSignature(),
+                                                      genericParams,
+                                                      requirements,
+                                                      /*allowInverses*/ false);
     // If there were any errors, the signature was invalid.
     auto errorFlags = newSigWithError.getInt();
     if (errorFlags.contains(GenericSignatureErrorFlags::HasInvalidRequirements) ||
@@ -1258,8 +1303,8 @@ void swift::validateGenericSignaturesInModule(ModuleDecl *module) {
   }
 }
 
-GenericSignature
-swift::buildGenericSignature(ASTContext &ctx,
+GenericSignatureWithError
+swift::buildGenericSignatureWithError(ASTContext &ctx,
                              GenericSignature baseSignature,
                              SmallVector<GenericTypeParamType *, 2> addedParameters,
                              SmallVector<Requirement, 2> addedRequirements,
@@ -1271,7 +1316,18 @@ swift::buildGenericSignature(ASTContext &ctx,
         addedParameters,
         addedRequirements,
         allowInverses},
-      GenericSignatureWithError()).getPointer();
+      GenericSignatureWithError());
+}
+
+GenericSignature
+swift::buildGenericSignature(ASTContext &ctx,
+                             GenericSignature baseSignature,
+                             SmallVector<GenericTypeParamType *, 2> addedParameters,
+                             SmallVector<Requirement, 2> addedRequirements,
+                             bool allowInverses) {
+  return buildGenericSignatureWithError(ctx, baseSignature,
+                                        addedParameters, addedRequirements,
+                                        allowInverses).getPointer();
 }
 
 GenericSignature GenericSignature::withoutMarkerProtocols() const {
@@ -1344,33 +1400,13 @@ RequirementSignature RequirementSignature::getPlaceholderRequirementSignature(
     const ProtocolDecl *proto, GenericSignatureErrors errors) {
   auto &ctx = proto->getASTContext();
 
-  SmallVector<ProtocolDecl *, 2> inheritedProtos;
-  for (auto *inheritedProto : proto->getInheritedProtocols()) {
-    inheritedProtos.push_back(inheritedProto);
-  }
-
+  // Pretend the protocol inherits from Copyable and Escapable.
+  SmallVector<Requirement, 2> requirements;
   for (auto ip : InvertibleProtocolSet::allKnown()) {
     auto *otherProto = ctx.getProtocol(getKnownProtocolKind(ip));
-    inheritedProtos.push_back(otherProto);
-  }
-
-  ProtocolType::canonicalizeProtocols(inheritedProtos);
-
-  SmallVector<Requirement, 2> requirements;
-
-  for (auto *inheritedProto : inheritedProtos) {
     requirements.emplace_back(RequirementKind::Conformance,
                               proto->getSelfInterfaceType(),
-                              inheritedProto->getDeclaredInterfaceType());
-  }
-
-  for (auto *assocTypeDecl : proto->getAssociatedTypeMembers()) {
-    for (auto ip : InvertibleProtocolSet::allKnown()) {
-      auto *otherProto = ctx.getProtocol(getKnownProtocolKind(ip));
-      requirements.emplace_back(RequirementKind::Conformance,
-                                assocTypeDecl->getDeclaredInterfaceType(),
-                                otherProto->getDeclaredInterfaceType());
-    }
+                              otherProto->getDeclaredInterfaceType());
   }
 
   // Maintain invariants.
@@ -1380,7 +1416,8 @@ RequirementSignature RequirementSignature::getPlaceholderRequirementSignature(
                        });
 
   return RequirementSignature(ctx.AllocateCopy(requirements),
-                              ArrayRef<ProtocolTypeAlias>());
+                              ArrayRef<ProtocolTypeAlias>(),
+                              errors);
 }
 
 void RequirementSignature::getRequirementsWithInverses(
diff --git a/lib/AST/Identifier.cpp b/lib/AST/Identifier.cpp
index 90bf6e612f69c..1cb2c3838d67d 100644
--- a/lib/AST/Identifier.cpp
+++ b/lib/AST/Identifier.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -55,6 +55,8 @@ void swift::simple_display(llvm::raw_ostream &out, DeclName name) {
 }
 
 raw_ostream &llvm::operator<<(raw_ostream &OS, DeclNameRef I) {
+  if (I.hasModuleSelector())
+    OS << I.getModuleSelector() << "::";
   OS << I.getFullName();
   return OS;
 }
@@ -78,6 +80,10 @@ raw_ostream &llvm::operator<<(raw_ostream &OS, swift::ObjCSelector S) {
   return OS;
 }
 
+bool Identifier::isEditorPlaceholder() const {
+  return !empty() && isEditorPlaceholder(str());
+}
+
 bool Identifier::isOperatorSlow() const { return Lexer::isOperator(str()); }
 
 bool Identifier::mustAlwaysBeEscaped() const {
@@ -164,9 +170,15 @@ StringRef DeclName::getString(llvm::SmallVectorImpl<char> &scratch,
 }
 
 llvm::raw_ostream &DeclName::print(llvm::raw_ostream &os,
-                                   bool skipEmptyArgumentNames) const {
+                                   bool skipEmptyArgumentNames,
+                                   bool escapeIfNeeded) const {
   // Print the base name.
-  os << getBaseName();
+  auto baseName = getBaseName();
+  if (escapeIfNeeded && baseName.mustAlwaysBeEscaped()) {
+    os << "`" << baseName << "`";
+  } else {
+    os << baseName;
+  }
 
   // If this is a simple name, we're done.
   if (isSimpleName())
@@ -191,8 +203,13 @@ llvm::raw_ostream &DeclName::print(llvm::raw_ostream &os,
 
   // Print the argument names.
   os << "(";
-  for (auto c : getArgumentNames()) {
-    os << c << ':';
+  for (auto argName : getArgumentNames()) {
+    if (escapeIfNeeded && argName.mustAlwaysBeEscaped()) {
+      os << "`" << argName << "`";
+    } else {
+      os << argName;
+    }
+    os << ':';
   }
   os << ")";
   return os;
@@ -208,17 +225,27 @@ void DeclNameRef::dump() const {
 }
 
 StringRef DeclNameRef::getString(llvm::SmallVectorImpl<char> &scratch,
-                             bool skipEmptyArgumentNames) const {
-  return FullName.getString(scratch, skipEmptyArgumentNames);
+                                 bool skipEmptyArgumentNames) const {
+  {
+    llvm::raw_svector_ostream out(scratch);
+    print(out, skipEmptyArgumentNames);
+  }
+
+  return StringRef(scratch.data(), scratch.size());
 }
 
-llvm::raw_ostream &DeclNameRef::print(llvm::raw_ostream &os,
-                                  bool skipEmptyArgumentNames) const {
-  return FullName.print(os, skipEmptyArgumentNames);
+llvm::raw_ostream &
+DeclNameRef::print(llvm::raw_ostream &os,
+                   bool skipEmptyArgumentNames) const {
+  if (hasModuleSelector())
+    os << getModuleSelector() << "::";
+  return getFullName().print(os, skipEmptyArgumentNames);
 }
 
 llvm::raw_ostream &DeclNameRef::printPretty(llvm::raw_ostream &os) const {
-  return FullName.printPretty(os);
+  if (hasModuleSelector())
+    os << getModuleSelector() << "::";
+  return getFullName().printPretty(os);
 }
 
 ObjCSelector::ObjCSelector(ASTContext &ctx, unsigned numArgs,
diff --git a/lib/AST/ImportCache.cpp b/lib/AST/ImportCache.cpp
index 0567151a37dac..3a8db740179c9 100644
--- a/lib/AST/ImportCache.cpp
+++ b/lib/AST/ImportCache.cpp
@@ -35,7 +35,7 @@ ImportSet::ImportSet(bool hasHeaderImportModule,
     NumTopLevelImports(topLevelImports.size()),
     NumTransitiveImports(transitiveImports.size()),
     NumTransitiveSwiftOnlyImports(transitiveSwiftOnlyImports.size()) {
-  auto buffer = getTrailingObjects<ImportedModule>();
+  auto *buffer = getTrailingObjects();
   std::uninitialized_copy(topLevelImports.begin(), topLevelImports.end(),
                           buffer);
   std::uninitialized_copy(transitiveImports.begin(), transitiveImports.end(),
diff --git a/lib/AST/LifetimeDependence.cpp b/lib/AST/LifetimeDependence.cpp
index 8bdef9dc4b73d..6e6612c29f5fe 100644
--- a/lib/AST/LifetimeDependence.cpp
+++ b/lib/AST/LifetimeDependence.cpp
@@ -12,6 +12,7 @@
 
 #include "swift/AST/LifetimeDependence.h"
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/ASTPrinter.h"
 #include "swift/AST/Builtins.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
@@ -25,9 +26,28 @@
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/Range.h"
 #include "swift/Basic/SourceManager.h"
+#include "llvm/ADT/MapVector.h"
 
 namespace swift {
 
+std::string LifetimeDescriptor::getString() const {
+  switch (kind) {
+  case DescriptorKind::Named: {
+    bool shouldEscape =
+        escapeIdentifierInContext(getName(), PrintNameContext::Normal);
+    if (shouldEscape) {
+      return ("`" + getName().str() + "`").str();
+    }
+    return getName().str().str();
+  }
+  case DescriptorKind::Ordered:
+    return std::to_string(getIndex());
+  case DescriptorKind::Self:
+    return "self";
+  }
+  llvm_unreachable("Invalid DescriptorKind");
+}
+
 LifetimeEntry *
 LifetimeEntry::create(const ASTContext &ctx, SourceLoc startLoc,
                       SourceLoc endLoc, ArrayRef<LifetimeDescriptor> sources,
@@ -37,6 +57,35 @@ LifetimeEntry::create(const ASTContext &ctx, SourceLoc startLoc,
   return new (mem) LifetimeEntry(startLoc, endLoc, sources, targetDescriptor);
 }
 
+std::string LifetimeEntry::getString() const {
+  std::string result = "(";
+  if (targetDescriptor.has_value()) {
+    result += targetDescriptor->getString();
+    result += ": ";
+  }
+
+  bool firstElem = true;
+  for (auto source : getSources()) {
+    if (!firstElem) {
+      result += ", ";
+    }
+    auto lifetimeKind = source.getParsedLifetimeDependenceKind();
+    auto kindString = getNameForParsedLifetimeDependenceKind(lifetimeKind);
+    bool printSpace = (lifetimeKind == ParsedLifetimeDependenceKind::Borrow ||
+                       lifetimeKind == ParsedLifetimeDependenceKind::Inherit);
+    if (!kindString.empty()) {
+      result += kindString;
+    }
+    if (printSpace) {
+      result += " ";
+    }
+    result += source.getString();
+    firstElem = false;
+  }
+  result += ")";
+  return result;
+}
+
 std::optional<LifetimeDependenceInfo>
 getLifetimeDependenceFor(ArrayRef<LifetimeDependenceInfo> lifetimeDependencies,
                          unsigned index) {
@@ -58,7 +107,12 @@ filterEscapableLifetimeDependencies(GenericSignature sig,
   for (auto &depInfo : inputs) {
     auto targetIndex = depInfo.getTargetIndex();
     Type substTy = getSubstTargetType(targetIndex);
-    
+
+    // If the type still contains type variables we don't know whether we
+    // can drop the dependency.
+    if (substTy->hasTypeVariable())
+      continue;
+
     // Drop the dependency if the target type is Escapable.
     if (sig || !substTy->hasTypeParameter()) {
       if (substTy->isEscapable(sig)) {
@@ -74,6 +128,20 @@ filterEscapableLifetimeDependencies(GenericSignature sig,
   return didRemoveLifetimeDependencies;
 }
 
+StringRef
+getNameForParsedLifetimeDependenceKind(ParsedLifetimeDependenceKind kind) {
+  switch (kind) {
+  case ParsedLifetimeDependenceKind::Borrow:
+    return "borrow";
+  case ParsedLifetimeDependenceKind::Inherit:
+    return "copy";
+  case ParsedLifetimeDependenceKind::Inout:
+    return "&";
+  default:
+    return "";
+  }
+}
+
 std::string LifetimeDependenceInfo::getString() const {
   std::string lifetimeDependenceString = "@lifetime(";
   auto addressable = getAddressableIndices();
@@ -138,25 +206,18 @@ void LifetimeDependenceInfo::Profile(llvm::FoldingSetNodeID &ID) const {
   }
 }
 
-// Infer the kind of dependence that would be implied by assigning into a stored
-// property of 'sourceType'.
-static LifetimeDependenceKind
-inferLifetimeDependenceKindFromType(Type sourceType) {
-  if (sourceType->isEscapable()) {
-    return LifetimeDependenceKind::Scope;
-  }
-  return LifetimeDependenceKind::Inherit;
-}
-
-// Warning: this is incorrect for Setter 'newValue' parameters. It should only
-// be called for a Setter's 'self'.
-static ValueOwnership getLoweredOwnership(AbstractFunctionDecl *afd) {
+static ValueOwnership getLoweredOwnership(ParamDecl *param,
+                                          AbstractFunctionDecl *afd) {
   if (isa<ConstructorDecl>(afd)) {
     return ValueOwnership::Owned;
   }
   if (auto *ad = dyn_cast<AccessorDecl>(afd)) {
-    if (ad->getAccessorKind() == AccessorKind::Set ||
-        isYieldingMutableAccessor(ad->getAccessorKind())) {
+    if (ad->getAccessorKind() == AccessorKind::Set) {
+      return param->isSelfParameter() ? ValueOwnership::InOut
+                                      : ValueOwnership::Owned;
+    }
+    if (isYieldingMutableAccessor(ad->getAccessorKind())) {
+      assert(param->isSelfParameter());
       return ValueOwnership::InOut;
     }
   }
@@ -169,6 +230,9 @@ static bool isBitwiseCopyable(Type type, ASTContext &ctx) {
   if (!bitwiseCopyableProtocol) {
     return false;
   }
+  if (type->hasError())
+    return false;
+
   return (bool)checkConformance(type, bitwiseCopyableProtocol);
 }
 
@@ -186,6 +250,13 @@ static bool isDiagnosedNonEscapable(Type type) {
   return !type->isEscapable();
 }
 
+static bool isDiagnosedEscapable(Type type) {
+  if (type->hasError()) {
+    return false;
+  }
+  return type->isEscapable();
+}
+
 void LifetimeDependenceInfo::getConcatenatedData(
     SmallVectorImpl<bool> &concatenatedData) const {
   auto pushData = [&](IndexSubset *paramIndices) {
@@ -213,8 +284,144 @@ void LifetimeDependenceInfo::getConcatenatedData(
   }
 }
 
+// Temporary data structure for building target dependencies. Used by the
+// LifetimeDependenceChecker.
+struct LifetimeDependenceBuilder {
+  struct TargetDeps {
+    SmallBitVector inheritIndices;
+    SmallBitVector scopeIndices;
+    bool hasAnnotation;
+    bool isImmortal = false;
+
+    TargetDeps(bool hasAnnotation, unsigned capacity)
+        : inheritIndices(capacity), scopeIndices(capacity),
+          hasAnnotation(hasAnnotation) {}
+
+    bool empty() const {
+      return !(isImmortal || inheritIndices.any() || scopeIndices.any());
+    }
+
+    void addIfNew(unsigned sourceIndex, LifetimeDependenceKind kind) {
+      // Some inferrence rules may attempt to add an inherit dependency after a
+      // scope dependency (accessor wrapper + getter method).
+      if (isImmortal || inheritIndices[sourceIndex]
+          || scopeIndices[sourceIndex]) {
+        return;
+      }
+      switch (kind) {
+      case LifetimeDependenceKind::Inherit:
+        inheritIndices.set(sourceIndex);
+        break;
+      case LifetimeDependenceKind::Scope:
+        scopeIndices.set(sourceIndex);
+        break;
+      }
+    }
+  };
+
+  const unsigned sourceIndexCap;
+
+  LifetimeDependenceBuilder(int sourceIndexCap)
+      : sourceIndexCap(sourceIndexCap) {}
+
+  llvm::SmallMapVector<unsigned, TargetDeps, 4> depsArray;
+
+public:
+  // True if the builder is uninitialized. This may, however, be false even if
+  // all TargetDeps are themselves empty.
+  bool empty() const { return depsArray.empty(); }
+
+  // Return TargetDeps for 'targetIndex' if it has at least one source
+  // dependency.
+  const TargetDeps *getTargetDepsOrNull(unsigned targetIndex) const {
+    auto iter = depsArray.find(targetIndex);
+    if (iter != depsArray.end() && !iter->second.empty()) {
+      return &iter->second;
+    }
+    return nullptr;
+  }
+
+  bool hasTargetDeps(unsigned targetIndex) const {
+    return getTargetDepsOrNull(targetIndex) != nullptr;
+  }
+
+  TargetDeps *createAnnotatedTargetDeps(unsigned targetIndex) {
+    auto iterAndInserted = depsArray.try_emplace(targetIndex, true,
+                                                 sourceIndexCap);
+    if (!iterAndInserted.second)
+      return nullptr;
+
+    return &iterAndInserted.first->second;
+  }
+
+  // Check this before diagnosing any broken inference to avoid diagnosing a
+  // target that has an explicit annotation.
+  TargetDeps *getInferredTargetDeps(unsigned targetIndex) {
+    auto iter = depsArray.try_emplace(targetIndex, false, sourceIndexCap).first;
+    auto &deps = iter->second;
+    return deps.hasAnnotation ? nullptr : &deps;
+  }
+
+  void inferDependency(unsigned targetIndex, unsigned sourceIndex,
+                       LifetimeDependenceKind kind) {
+    auto targetDeps = getInferredTargetDeps(targetIndex);
+    if (!targetDeps)
+      return;
+    targetDeps->addIfNew(sourceIndex, kind);
+  }
+
+  void inferInoutDependency(unsigned paramIndex) {
+    inferDependency(paramIndex, paramIndex, LifetimeDependenceKind::Inherit);
+  }
+
+  // Allocate LifetimeDependenceInfo in the ASTContext. Initialize it by
+  // copying heap-allocated TargetDeps fields into ASTContext allocations
+  // (e.g. convert SmallBitVector to IndexSubset).
+  std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>
+  initializeDependenceInfoArray(ASTContext &ctx) const {
+    if (depsArray.empty()) {
+      return std::nullopt;
+    }
+    // Inference might attempt to infer a target, but fail leaving the source
+    // indices empty.
+    SmallVector<LifetimeDependenceInfo, 4> lifetimeDependencies;
+    for (auto &idxAndDeps : depsArray) {
+      unsigned targetIndex = idxAndDeps.first;
+      auto &deps = idxAndDeps.second;
+      if (deps.empty())
+        continue;
+
+      IndexSubset *inheritIndices = nullptr;
+      if (deps.inheritIndices.any()) {
+        inheritIndices = IndexSubset::get(ctx, deps.inheritIndices);
+        ASSERT(!deps.isImmortal
+               && "cannot combine immortal lifetime with parameter dependency");
+      }
+      IndexSubset *scopeIndices = nullptr;
+      if (deps.scopeIndices.any()) {
+        scopeIndices = IndexSubset::get(ctx, deps.scopeIndices);
+        ASSERT(!deps.isImmortal
+               && "cannot combine immortal lifetime with parameter dependency");
+      }
+      lifetimeDependencies.push_back(LifetimeDependenceInfo{
+          /*inheritLifetimeParamIndices*/ inheritIndices,
+          /*scopeLifetimeParamIndices*/ scopeIndices, targetIndex,
+          /*isImmortal*/ deps.isImmortal});
+    }
+    if (lifetimeDependencies.empty()) {
+      return std::nullopt;
+    }
+    return ctx.AllocateCopy(lifetimeDependencies);
+  }
+};
+
+/// Diagnostics for ~Escpable types in function signatures. This lowers
+/// @_lifetime attributes to the SILFunction's lifetime dependencies and
+/// implements the lifetime inferrence rules.
 class LifetimeDependenceChecker {
-  AbstractFunctionDecl *afd;
+  using TargetDeps = LifetimeDependenceBuilder::TargetDeps;
+
+  ValueDecl *decl;
 
   DeclContext *dc;
   ASTContext &ctx;
@@ -228,41 +435,57 @@ class LifetimeDependenceChecker {
   // represent the function result.
   unsigned resultIndex = ~0;
 
-  SmallVector<LifetimeDependenceInfo, 1> lifetimeDependencies;
+  LifetimeDependenceBuilder depBuilder;
 
   // True if lifetime diganostics have already been performed. Avoids redundant
   // diagnostics, and allows bypassing diagnostics for special cases.
   bool performedDiagnostics = false;
 
 public:
-  LifetimeDependenceChecker(AbstractFunctionDecl *afd):
-    afd(afd), dc(afd->getDeclContext()), ctx(dc->getASTContext())
-  {
+  static int getResultIndex(AbstractFunctionDecl *afd) {
+    return afd->hasImplicitSelfDecl() ? (afd->getParameters()->size() + 1)
+                                      : afd->getParameters()->size();
+  }
+
+  static int getResultIndex(EnumElementDecl *eed) {
+    auto *paramList = eed->getParameterList();
+    return paramList ? paramList->size() + 1 : 1;
+  }
+
+public:
+  LifetimeDependenceChecker(AbstractFunctionDecl *afd)
+      : decl(afd), dc(afd->getDeclContext()), ctx(dc->getASTContext()),
+        resultIndex(getResultIndex(afd)),
+        depBuilder(/*sourceIndexCap*/ resultIndex) {
+
     auto resultTypeRepr = afd->getResultTypeRepr();
     returnLoc = resultTypeRepr ? resultTypeRepr->getLoc() : afd->getLoc();
 
     if (afd->hasImplicitSelfDecl()) {
       selfIndex = afd->getParameters()->size();
-      resultIndex = selfIndex + 1;
-    } else {
-      resultIndex = afd->getParameters()->size();
     }
   }
 
+  LifetimeDependenceChecker(EnumElementDecl *eed)
+      : decl(eed), dc(eed->getDeclContext()), ctx(dc->getASTContext()),
+        resultIndex(getResultIndex(eed)),
+        depBuilder(/*sourceIndexCap*/ resultIndex) {
+
+    selfIndex = resultIndex - 1;
+  }
+
   std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>
   currentDependencies() const {
-    if (lifetimeDependencies.empty()) {
-      return std::nullopt;
-    }
-    return afd->getASTContext().AllocateCopy(lifetimeDependencies);
+    return depBuilder.initializeDependenceInfoArray(ctx);
   }
 
   std::optional<llvm::ArrayRef<LifetimeDependenceInfo>> checkFuncDecl() {
-    assert(isa<FuncDecl>(afd) || isa<ConstructorDecl>(afd));
-    assert(lifetimeDependencies.empty());
+    assert(isa<FuncDecl>(decl) || isa<ConstructorDecl>(decl));
+    assert(depBuilder.empty());
 
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     // Handle Builtins first because, even though Builtins require
-    // LifetimeDependence, we don't force Feature::LifetimeDependence
+    // LifetimeDependence, we don't force the experimental feature
     // to be enabled when importing the Builtin module.
     if (afd->isImplicit() && afd->getModuleContext()->isBuiltinModule()) {
       inferBuiltin();
@@ -270,23 +493,35 @@ class LifetimeDependenceChecker {
     }
 
     if (!ctx.LangOpts.hasFeature(Feature::LifetimeDependence)
+        && !ctx.LangOpts.hasFeature(Feature::Lifetimes)
         && !ctx.SourceMgr.isImportMacroGeneratedLoc(returnLoc)) {
+
+      // Infer inout dependencies without requiring a feature flag. On
+      // returning, 'depBuilder' contains any inferred dependencies. This does
+      // not issue any diagnostics because using unsupported lifetime features
+      // may generate a different diagnostic when the feature flag is disabled.
+      inferMutatingSelf();
+      inferInoutParams();
+
       diagnoseMissingResultDependencies(
         diag::lifetime_dependence_feature_required_return.ID);
       diagnoseMissingSelfDependencies(
         diag::lifetime_dependence_feature_required_mutating.ID);
       diagnoseMissingInoutDependencies(
         diag::lifetime_dependence_feature_required_inout.ID);
-      return std::nullopt;
+
+      return currentDependencies();
     }
 
     if (afd->getAttrs().hasAttribute<LifetimeAttr>()) {
-      return checkAttribute();
+      initializeAttributeDeps();
+      if (performedDiagnostics)
+        return std::nullopt;
     }
     // Methods or functions with @_unsafeNonescapableResult do not require
     // lifetime annotation and do not infer any lifetime dependency.
     if (afd->getAttrs().hasAttribute<UnsafeNonEscapableResultAttr>()) {
-      return std::nullopt;
+      return currentDependencies();
     }
 
     inferOrDiagnose();
@@ -304,6 +539,41 @@ class LifetimeDependenceChecker {
     return currentDependencies();
   }
 
+  std::optional<llvm::ArrayRef<LifetimeDependenceInfo>> checkEnumElementDecl() {
+    auto *eed = cast<EnumElementDecl>(decl);
+    auto *parentEnum = eed->getParentEnum();
+    auto enumType =
+        parentEnum->mapTypeIntoContext(parentEnum->getDeclaredInterfaceType());
+
+    // Add early bailout for imported enums.
+    if (parentEnum->hasClangNode()) {
+      return std::nullopt;
+    }
+
+    // Escapable enum, bailout.
+    if (!isDiagnosedNonEscapable(enumType)) {
+      return std::nullopt;
+    }
+    auto *params = eed->getParameterList();
+    // No payload, bailout.
+    if (!params) {
+      return std::nullopt;
+    }
+
+    TargetDeps *resultDeps = depBuilder.getInferredTargetDeps(resultIndex);
+    ASSERT(resultDeps && "enum declaration has a lifetime attribute");
+
+    // Add all indices of ~Escapable parameters as lifetime dependence sources.
+    for (size_t i = 0; i < params->size(); i++) {
+      auto paramType = params->get(i)->getTypeInContext();
+      if (!isDiagnosedNonEscapable(paramType)) {
+        continue;
+      }
+      resultDeps->inheritIndices.set(i);
+    }
+    return currentDependencies();
+  }
+
 protected:
   template<typename ...ArgTypes>
   InFlightDiagnostic diagnose(
@@ -313,16 +583,17 @@ class LifetimeDependenceChecker {
     return ctx.Diags.diagnose(Loc, ID, std::move(Args)...);
   }
 
+  // Issue a diagnostic for an @_lifetime attribute. This does not set
+  // 'performedDiagnostics', so other lifetime diagnosics are raised as if the
+  // attribute was not present.
   template<typename ...ArgTypes>
   InFlightDiagnostic
-  diagnose(const Decl *decl, Diag<ArgTypes...> id,
-           typename detail::PassArgument<ArgTypes>::type... args) {
+  diagnoseAttr(const Decl *decl, Diag<ArgTypes...> id,
+               typename detail::PassArgument<ArgTypes>::type... args) {
     return ctx.Diags.diagnose(decl, Diagnostic(id, std::move(args)...));
   }
 
-  bool isInit() const {
-    return isa<ConstructorDecl>(afd);
-  }
+  bool isInit() const { return isa<ConstructorDecl>(decl); }
 
   // For initializers, the implicit self parameter is ignored and instead shows
   // up as the result type.
@@ -334,11 +605,13 @@ class LifetimeDependenceChecker {
   // the extra formal self parameter, a dependency targeting the formal result
   // index would incorrectly target the SIL metatype parameter.
   bool hasImplicitSelfParam() const {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     return !isInit() && afd->hasImplicitSelfDecl();
   }
 
   // In SIL, implicit initializers and accessors become explicit.
   bool isImplicitOrSIL() const {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     if (afd->isImplicit()) {
       return true;
     }
@@ -357,7 +630,7 @@ class LifetimeDependenceChecker {
   bool isInterfaceFile() const {
     // TODO: remove this check once all compilers that are rev-locked to the
     // stdlib print the 'copy' dependence kind in the interface (Aug '25)
-    if (auto *sf = afd->getParentSourceFile()) {
+    if (auto *sf = decl->getDeclContext()->getParentSourceFile()) {
       if (sf->Kind == SourceFileKind::Interface) {
         return true;
       }
@@ -365,12 +638,18 @@ class LifetimeDependenceChecker {
     return false;
   }
 
+  // Infer ambiguous cases for backward compatibility.
   bool useLazyInference() const {
     return isInterfaceFile()
       || ctx.LangOpts.EnableExperimentalLifetimeDependenceInference;
   }
 
+  // ==========================================================================
+  // MARK: Catch-all diagnostics for missing attributes and inferrence rules.
+  // ==========================================================================
+
   std::string diagnosticQualifier() const {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     if (afd->isImplicit()) {
       if (isInit()) {
         return "an implicit initializer";
@@ -401,10 +680,7 @@ class LifetimeDependenceChecker {
     if (!isDiagnosedNonEscapable(getResultOrYield())) {
       return;
     }
-    if (llvm::none_of(lifetimeDependencies,
-                      [&](LifetimeDependenceInfo dep) {
-                        return dep.getTargetIndex() == resultIndex;
-                      })) {
+    if (!depBuilder.hasTargetDeps(resultIndex)) {
       ctx.Diags.diagnose(returnLoc, diagID,
                          {StringRef(diagnosticQualifier())});
     }
@@ -415,6 +691,7 @@ class LifetimeDependenceChecker {
   // initializers, the inout self parameter is actually considered the result
   // type so is not handled here.
   void diagnoseMissingSelfDependencies(DiagID diagID) {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     if (!hasImplicitSelfParam()) {
       return;
     }
@@ -425,16 +702,14 @@ class LifetimeDependenceChecker {
     if (!isDiagnosedNonEscapable(dc->getSelfTypeInContext())) {
       return;
     }
-    if (llvm::none_of(lifetimeDependencies,
-                      [&](LifetimeDependenceInfo dep) {
-                        return dep.getTargetIndex() == selfIndex;
-                      })) {
+    if (!depBuilder.hasTargetDeps(selfIndex)) {
       ctx.Diags.diagnose(selfDecl->getLoc(), diagID,
                          {StringRef(diagnosticQualifier())});
     }
   }
   
   void diagnoseMissingInoutDependencies(DiagID diagID) {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     unsigned paramIndex = 0;
     for (auto *param : *afd->getParameters()) {
       SWIFT_DEFER { paramIndex++; };
@@ -445,92 +720,77 @@ class LifetimeDependenceChecker {
             afd->mapTypeIntoContext(param->getInterfaceType()))) {
         continue;
       }
-      if (llvm::none_of(lifetimeDependencies,
-                        [&](LifetimeDependenceInfo dep) {
-                          return dep.getTargetIndex() == paramIndex;
-                        })) {
+      if (!depBuilder.hasTargetDeps(paramIndex)) {
         ctx.Diags.diagnose(param->getLoc(), diagID,
                            {StringRef(diagnosticQualifier()),
-                            param->getName()});
+                            param->getName().str()});
+        if (diagID == diag::lifetime_dependence_cannot_infer_inout.ID) {
+          ctx.Diags.diagnose(
+            param->getLoc(),
+            diag::lifetime_dependence_cannot_infer_inout_suggest,
+            param->getName().str());
+        }
       }
     }
   }
 
-  bool isCompatibleWithOwnership(LifetimeDependenceKind kind, Type type,
-                                 ValueOwnership ownership) const {
-    if (kind == LifetimeDependenceKind::Inherit) {
-      return true;
-    }
-    // Lifetime dependence always propagates through temporary BitwiseCopyable
-    // values, even if the dependence is scoped.
-    if (isBitwiseCopyable(type, ctx)) {
-      return true;
-    }
-    assert(kind == LifetimeDependenceKind::Scope);
-    auto loweredOwnership = ownership != ValueOwnership::Default
-      ? ownership : getLoweredOwnership(afd);
-
-    if (loweredOwnership == ValueOwnership::InOut ||
-        loweredOwnership == ValueOwnership::Shared) {
+  // Attribute parsing helper.
+  bool isCompatibleWithOwnership(ParsedLifetimeDependenceKind kind,
+                                 ParamDecl *param,
+                                 bool isInterfaceFile = false) const {
+    if (kind == ParsedLifetimeDependenceKind::Inherit) {
       return true;
     }
-    assert(loweredOwnership == ValueOwnership::Owned);
-    return false;
-  }
 
-  struct TargetDeps {
-    unsigned targetIndex;
-    SmallBitVector inheritIndices;
-    SmallBitVector scopeIndices;
-
-    TargetDeps(unsigned targetIndex, unsigned capacity)
-      : targetIndex(targetIndex), inheritIndices(capacity),
-        scopeIndices(capacity) {}
-
-    TargetDeps &&add(unsigned sourceIndex, LifetimeDependenceKind kind) && {
-      switch (kind) {
-      case LifetimeDependenceKind::Inherit:
-        inheritIndices.set(sourceIndex);
-        break;
-      case LifetimeDependenceKind::Scope:
-        scopeIndices.set(sourceIndex);
-        break;
+    auto *afd = cast<AbstractFunctionDecl>(decl);
+    auto paramType = param->getTypeInContext();
+    auto ownership = param->getValueOwnership();
+    auto loweredOwnership = ownership != ValueOwnership::Default
+                                ? ownership
+                                : getLoweredOwnership(param, afd);
+
+    if (kind == ParsedLifetimeDependenceKind::Borrow) {
+      // An owned/consumed BitwiseCopyable value can be effectively borrowed
+      // because its lifetime can be indefinitely extended.
+      if (loweredOwnership == ValueOwnership::Owned &&
+          isBitwiseCopyable(paramType, ctx)) {
+        return true;
       }
-      return std::move(*this);
+      if (isInterfaceFile) {
+        return loweredOwnership == ValueOwnership::Shared ||
+               loweredOwnership == ValueOwnership::InOut;
+      }
+      return loweredOwnership == ValueOwnership::Shared;
     }
-  };
-
-  TargetDeps createDeps(unsigned targetIndex) {
-    unsigned capacity = afd->hasImplicitSelfDecl()
-      ? (afd->getParameters()->size() + 1)
-      : afd->getParameters()->size();
-    return TargetDeps(targetIndex, capacity);
+    assert(kind == ParsedLifetimeDependenceKind::Inout);
+    return loweredOwnership == ValueOwnership::InOut;
   }
 
-  // Allocate LifetimeDependenceInfo in the ASTContext and push it onto
-  // lifetimeDependencies.
-  void pushDeps(const TargetDeps &&deps) {
-    assert(llvm::none_of(lifetimeDependencies,
-                         [&](LifetimeDependenceInfo dep) {
-                           return dep.getTargetIndex() == deps.targetIndex;
-                         }));
-    IndexSubset *inheritIndices = nullptr;
-    if (deps.inheritIndices.any()) {
-      inheritIndices = IndexSubset::get(ctx, deps.inheritIndices);
+  // Inferrence helper.
+  bool isCompatibleWithOwnership(LifetimeDependenceKind kind,
+                                 ParamDecl *param) const {
+    if (kind == LifetimeDependenceKind::Inherit) {
+      return true;
     }
-    IndexSubset *scopeIndices = nullptr;
-    if (deps.scopeIndices.any()) {
-      scopeIndices = IndexSubset::get(ctx, deps.scopeIndices);
+
+    auto *afd = cast<AbstractFunctionDecl>(decl);
+    auto paramType = param->getTypeInContext();
+    auto ownership = param->getValueOwnership();
+    auto loweredOwnership = ownership != ValueOwnership::Default
+                                ? ownership
+                                : getLoweredOwnership(param, afd);
+    // Lifetime dependence always propagates through temporary BitwiseCopyable
+    // values, even if the dependence is scoped.
+    if (isBitwiseCopyable(paramType, ctx)) {
+      return true;
     }
-    lifetimeDependencies.push_back(
-      LifetimeDependenceInfo{
-        /*inheritLifetimeParamIndices*/ inheritIndices,
-        /*scopeLifetimeParamIndices*/ scopeIndices,
-        deps.targetIndex,
-        /*isImmortal*/ false});
+    assert(kind == LifetimeDependenceKind::Scope);
+    return loweredOwnership == ValueOwnership::Shared ||
+           loweredOwnership == ValueOwnership::InOut;
   }
 
   Type getResultOrYield() const {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     if (auto *accessor = dyn_cast<AccessorDecl>(afd)) {
       if (accessor->isCoroutine()) {
         auto yieldTyInContext = accessor->mapTypeIntoContext(
@@ -548,52 +808,98 @@ class LifetimeDependenceChecker {
     return afd->mapTypeIntoContext(resultType);
   }
 
+  // ==========================================================================
+  // MARK: @_lifetime attribute semantics
+  // ==========================================================================
+
   std::optional<LifetimeDependenceKind>
   getDependenceKindFromDescriptor(LifetimeDescriptor descriptor,
-                                  ParamDecl *decl) {
+                                  ParamDecl *paramDecl) {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     auto loc = descriptor.getLoc();
+    auto type = paramDecl->getTypeInContext();
+    auto parsedLifetimeKind = descriptor.getParsedLifetimeDependenceKind();
+    auto ownership = paramDecl->getValueOwnership();
+    auto loweredOwnership = ownership != ValueOwnership::Default
+                                ? ownership
+                                : getLoweredOwnership(paramDecl, afd);
 
-    auto ownership = decl->getValueOwnership();
-    auto type = decl->getTypeInContext();
-
-    LifetimeDependenceKind kind;
-    switch (descriptor.getParsedLifetimeDependenceKind()) {
-    case ParsedLifetimeDependenceKind::Default:
+    switch (parsedLifetimeKind) {
+    case ParsedLifetimeDependenceKind::Default: {
       if (type->isEscapable()) {
-        kind = LifetimeDependenceKind::Scope;
-      } else if (useLazyInference()) {
-        kind = LifetimeDependenceKind::Inherit;
-      } else {
-        diagnose(loc, diag::lifetime_dependence_cannot_infer_kind,
-                 diagnosticQualifier(), descriptor.getString());
+        if (loweredOwnership == ValueOwnership::Shared ||
+            loweredOwnership == ValueOwnership::InOut) {
+          return LifetimeDependenceKind::Scope;
+        }
+        diagnose(
+            loc,
+            diag::lifetime_dependence_cannot_use_default_escapable_consuming,
+            getOwnershipSpelling(loweredOwnership));
         return std::nullopt;
       }
-      break;
-    case ParsedLifetimeDependenceKind::Scope:
-      kind = LifetimeDependenceKind::Scope;
-      break;
-    case ParsedLifetimeDependenceKind::Inherit:
-      kind = LifetimeDependenceKind::Inherit;
-      break;
+      if (useLazyInference()) {
+        return LifetimeDependenceKind::Inherit;
+      }
+      diagnose(loc, diag::lifetime_dependence_cannot_infer_kind,
+               diagnosticQualifier(), descriptor.getString());
+      return std::nullopt;
     }
-    // @lifetime(borrow x) is invalid for consuming parameters.
-    if (!isCompatibleWithOwnership(kind, type, ownership)) {
+
+    case ParsedLifetimeDependenceKind::Borrow: LLVM_FALLTHROUGH;
+    case ParsedLifetimeDependenceKind::Inout: {
+      // @lifetime(borrow x) is valid only for borrowing parameters.
+      // @lifetime(&x) is valid only for inout parameters.
+      if (isCompatibleWithOwnership(parsedLifetimeKind, paramDecl,
+                                    isInterfaceFile())) {
+        return LifetimeDependenceKind::Scope;
+      }
       diagnose(loc,
-               diag::lifetime_dependence_cannot_use_parsed_borrow_consuming);
+               diag::lifetime_dependence_parsed_borrow_with_ownership,
+               getNameForParsedLifetimeDependenceKind(parsedLifetimeKind),
+               getOwnershipSpelling(loweredOwnership));
+      switch (loweredOwnership) {
+      case ValueOwnership::Shared:
+        diagnose(loc,
+                 diag::lifetime_dependence_parsed_borrow_with_ownership_fix,
+                 "borrow ", descriptor.getString());
+        break;
+      case ValueOwnership::InOut:
+        diagnose(loc,
+                 diag::lifetime_dependence_parsed_borrow_with_ownership_fix,
+                 "&", descriptor.getString());
+        break;
+      case ValueOwnership::Owned:
+      case ValueOwnership::Default:
+        break;
+      }
       return std::nullopt;
     }
-    // @lifetime(copy x) is only invalid for Escapable types.
-    if (kind == LifetimeDependenceKind::Inherit && type->isEscapable()) {
-      diagnose(loc, diag::lifetime_dependence_invalid_inherit_escapable_type,
-               descriptor.getString());
-      return std::nullopt;
+    case ParsedLifetimeDependenceKind::Inherit: {
+      // @lifetime(copy x) is only invalid for Escapable types.
+      if (type->isEscapable()) {
+        if (loweredOwnership == ValueOwnership::Shared) {
+          diagnose(loc, diag::lifetime_dependence_invalid_inherit_escapable_type,
+                   "borrow ", descriptor.getString());
+        } else if (loweredOwnership == ValueOwnership::InOut) {
+          diagnose(loc, diag::lifetime_dependence_invalid_inherit_escapable_type,
+                   "&", descriptor.getString());
+        } else {
+          diagnose(
+            loc,
+            diag::lifetime_dependence_cannot_use_default_escapable_consuming,
+            getOwnershipSpelling(loweredOwnership));
+        }
+        return std::nullopt;
+      }
+      return LifetimeDependenceKind::Inherit;
+    }
     }
-    return kind;
   }
 
   // Finds the ParamDecl* and its index from a LifetimeDescriptor
   std::optional<std::pair<ParamDecl *, unsigned>>
   getParamDeclFromDescriptor(LifetimeDescriptor descriptor) {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     switch (descriptor.getDescriptorKind()) {
     case LifetimeDescriptor::DescriptorKind::Named: {
       unsigned paramIndex = 0;
@@ -641,209 +947,324 @@ class LifetimeDependenceChecker {
     }
   }
 
-  std::optional<ArrayRef<LifetimeDependenceInfo>> checkAttribute() {
-    SmallVector<LifetimeDependenceInfo, 1> lifetimeDependencies;
-    llvm::SmallSet<unsigned, 1> lifetimeDependentTargets;
+  // Initialize 'depBuilder' based on the function's @_lifetime attributes.
+  void initializeAttributeDeps() {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     auto lifetimeAttrs = afd->getAttrs().getAttributes<LifetimeAttr>();
     for (auto attr : lifetimeAttrs) {
-      auto lifetimeDependenceInfo =
-        checkAttributeEntry(attr->getLifetimeEntry());
-      if (!lifetimeDependenceInfo.has_value()) {
-        return std::nullopt;
+      LifetimeEntry *entry = attr->getLifetimeEntry();
+      auto targetDescriptor = entry->getTargetDescriptor();
+      unsigned targetIndex;
+      if (targetDescriptor.has_value()) {
+        auto targetDeclAndIndex = getParamDeclFromDescriptor(*targetDescriptor);
+        if (!targetDeclAndIndex.has_value()) {
+          return;
+        }
+        // TODO: support dependencies on non-inout parameters.
+        if (!targetDeclAndIndex->first->isInOut()) {
+          diagnoseAttr(targetDeclAndIndex->first,
+                       diag::lifetime_parameter_requires_inout,
+                       targetDescriptor->getString());
+        }
+        if (isDiagnosedEscapable(
+                targetDeclAndIndex->first->getTypeInContext())) {
+          diagnose(targetDescriptor->getLoc(),
+                   diag::lifetime_target_requires_nonescapable, "target");
+        }
+        targetIndex = targetDeclAndIndex->second;
+      } else {
+        if (isDiagnosedEscapable(getResultOrYield())) {
+          diagnose(entry->getLoc(), diag::lifetime_target_requires_nonescapable,
+                   "result");
+        }
+        targetIndex = afd->hasImplicitSelfDecl()
+                          ? afd->getParameters()->size() + 1
+                          : afd->getParameters()->size();
+      }
+      TargetDeps *deps = depBuilder.createAnnotatedTargetDeps(targetIndex);
+      if (deps == nullptr) {
+        diagnose(attr->getLocation(),
+                 diag::lifetime_dependence_duplicate_target);
+        return;
       }
-      auto targetIndex = lifetimeDependenceInfo->getTargetIndex();
-      if (lifetimeDependentTargets.contains(targetIndex)) {
-        // TODO: Diagnose at the source location of the @lifetime attribute with
-        // duplicate target.
-        diagnose(afd->getLoc(), diag::lifetime_dependence_duplicate_target);
+      for (auto source : entry->getSources()) {
+        initializeDescriptorDeps(targetIndex, *deps, source);
       }
-      lifetimeDependentTargets.insert(targetIndex);
-      lifetimeDependencies.push_back(*lifetimeDependenceInfo);
     }
-
-    return afd->getASTContext().AllocateCopy(lifetimeDependencies);
   }
 
-  std::optional<LifetimeDependenceInfo>
-  checkAttributeEntry(LifetimeEntry *entry) {
-    auto capacity = afd->hasImplicitSelfDecl()
-      ? (afd->getParameters()->size() + 1)
-      : afd->getParameters()->size();
-
-    SmallBitVector inheritIndices(capacity);
-    SmallBitVector scopeIndices(capacity);
-
-    auto updateLifetimeIndices = [&](LifetimeDescriptor descriptor,
-                                     unsigned paramIndexToSet,
-                                     LifetimeDependenceKind lifetimeKind) {
-      if (inheritIndices.test(paramIndexToSet) ||
-          scopeIndices.test(paramIndexToSet)) {
-        diagnose(descriptor.getLoc(),
-                 diag::lifetime_dependence_duplicate_param_id);
-        return true;
+  // Initialize TargetDeps based on the function's @_lifetime attributes.
+  void initializeDescriptorDeps(unsigned targetIndex,
+                                TargetDeps &deps,
+                                LifetimeDescriptor source) {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
+    if (source.isImmortal()) {
+      // Record the immortal dependency even if it is invalid to suppress other diagnostics.
+      deps.isImmortal = true;
+      auto immortalParam = std::find_if(
+          afd->getParameters()->begin(), afd->getParameters()->end(),
+          [](ParamDecl *param) {
+            return param->getName().nonempty()
+                   && strcmp(param->getName().get(), "immortal") == 0;
+          });
+      if (immortalParam != afd->getParameters()->end()) {
+        diagnoseAttr(*immortalParam,
+                     diag::lifetime_dependence_immortal_conflict_name);
+        return;
       }
-      if (lifetimeKind == LifetimeDependenceKind::Inherit) {
-        inheritIndices.set(paramIndexToSet);
-      } else {
-        assert(lifetimeKind == LifetimeDependenceKind::Scope);
-        scopeIndices.set(paramIndexToSet);
+      if (deps.inheritIndices.any() || deps.scopeIndices.any()) {
+        diagnoseAttr(*immortalParam, diag::lifetime_dependence_immortal_alone);
       }
-      return false;
-    };
+      return;
+    }
 
-    auto targetDescriptor = entry->getTargetDescriptor();
-    unsigned targetIndex;
-    if (targetDescriptor.has_value()) {
-      auto targetDeclAndIndex = getParamDeclFromDescriptor(*targetDescriptor);
-      if (!targetDeclAndIndex.has_value()) {
-        return std::nullopt;
-      }
-      // TODO: support dependencies on non-inout parameters.
-      if (!targetDeclAndIndex->first->isInOut()) {
-        diagnose(targetDeclAndIndex->first,
-                 diag::lifetime_parameter_requires_inout,
-                 targetDescriptor->getName());
-      }
-      targetIndex = targetDeclAndIndex->second;
-    } else {
-      targetIndex = afd->hasImplicitSelfDecl()
-        ? afd->getParameters()->size() + 1
-        : afd->getParameters()->size();
-    }
-
-    for (auto source : entry->getSources()) {
-      if (source.isImmortal()) {
-        auto immortalParam =
-          std::find_if(afd->getParameters()->begin(),
-                       afd->getParameters()->end(), [](ParamDecl *param) {
-                         return strcmp(param->getName().get(), "immortal") == 0;
-                       });
-        if (immortalParam != afd->getParameters()->end()) {
-          diagnose(*immortalParam,
-                   diag::lifetime_dependence_immortal_conflict_name);
-          return std::nullopt;
-        }
-        return LifetimeDependenceInfo(nullptr, nullptr, targetIndex,
-                                      /*isImmortal*/ true);
-      }
+    auto paramDeclAndIndex = getParamDeclFromDescriptor(source);
+    if (!paramDeclAndIndex.has_value()) {
+      return;
+    }
+    auto *param = paramDeclAndIndex->first;
+    unsigned sourceIndex = paramDeclAndIndex->second;
+    auto lifetimeKind = getDependenceKindFromDescriptor(source, param);
+    if (!lifetimeKind.has_value()) {
+      return;
+    }
+    if (lifetimeKind == LifetimeDependenceKind::Scope && param->isInOut()
+        && sourceIndex == targetIndex) {
+      diagnose(source.getLoc(),
+               diag::lifetime_dependence_cannot_use_parsed_borrow_inout);
+      ctx.Diags.diagnose(source.getLoc(),
+                         diag::lifetime_dependence_cannot_infer_inout_suggest,
+                         param->getName().str());
 
-      auto paramDeclAndIndex = getParamDeclFromDescriptor(source);
-      if (!paramDeclAndIndex.has_value()) {
-        return std::nullopt;
-      }
-      auto lifetimeKind =
-        getDependenceKindFromDescriptor(source, paramDeclAndIndex->first);
-      if (!lifetimeKind.has_value()) {
-        return std::nullopt;
-      }
-      unsigned sourceIndex = paramDeclAndIndex->second;
-      if (lifetimeKind == LifetimeDependenceKind::Scope
-          && sourceIndex == targetIndex) {
-        diagnose(source.getLoc(),
-                 diag::lifetime_dependence_cannot_use_parsed_borrow_inout);
-        return std::nullopt;
-      }
-      bool hasError =
-        updateLifetimeIndices(source, sourceIndex, *lifetimeKind);
-      if (hasError) {
-        return std::nullopt;
-      }
+      return;
+    }
+    addDescriptorIndices(deps, source, sourceIndex, *lifetimeKind);
+  }
+
+  void addDescriptorIndices(TargetDeps &deps, LifetimeDescriptor descriptor,
+                            unsigned paramIndexToSet,
+                            LifetimeDependenceKind lifetimeKind) {
+    if (deps.isImmortal) {
+      diagnose(descriptor.getLoc(), diag::lifetime_dependence_immortal_alone);
+      return;
     }
+    if (deps.inheritIndices.test(paramIndexToSet)
+        || deps.scopeIndices.test(paramIndexToSet)) {
+      diagnose(descriptor.getLoc(),
+               diag::lifetime_dependence_duplicate_param_id);
+      return;
+    }
+    if (lifetimeKind == LifetimeDependenceKind::Inherit) {
+      deps.inheritIndices.set(paramIndexToSet);
+    } else {
+      assert(lifetimeKind == LifetimeDependenceKind::Scope);
+      deps.scopeIndices.set(paramIndexToSet);
+    }
+  }
+
+  // ==========================================================================
+  // MARK: Inferrence rules
+  // ==========================================================================
 
-    return LifetimeDependenceInfo(
-      inheritIndices.any() ? IndexSubset::get(ctx, inheritIndices) : nullptr,
-      scopeIndices.any() ? IndexSubset::get(ctx, scopeIndices) : nullptr,
-      targetIndex, /*isImmortal*/ false);
+  // Infer the kind of dependence that makes sense for reading or writing a
+  // stored property (for getters or initializers).
+  std::optional<LifetimeDependenceKind>
+  inferLifetimeDependenceKind(ParamDecl *param) {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
+    Type paramType = param->getTypeInContext();
+    ValueOwnership ownership = param->getValueOwnership();
+    if (!paramType->isEscapable()) {
+      return LifetimeDependenceKind::Inherit;
+    }
+    // Lifetime dependence always propagates through temporary BitwiseCopyable
+    // values, even if the dependence is scoped.
+    if (isBitwiseCopyable(paramType, ctx)) {
+      return LifetimeDependenceKind::Scope;
+    }
+    auto loweredOwnership = ownership != ValueOwnership::Default
+                                ? ownership
+                                : getLoweredOwnership(param, afd);
+    // It is impossible to depend on a consumed Escapable value (unless it is
+    // BitwiseCopyable as checked above).
+    if (loweredOwnership == ValueOwnership::Owned) {
+      return std::nullopt;
+    }
+    return LifetimeDependenceKind::Scope;
   }
 
-  // On returning, 'lifetimeDependencies' contains any inferred dependencies and
+  // On returning, 'depBuilder' contains any inferred dependencies and
   // 'performedDiagnostics' indicates whether any specific diagnostics were
   // issued.
   void inferOrDiagnose() {
+    if (auto accessor = dyn_cast<AccessorDecl>(decl)) {
+      inferAccessor(accessor);
+      // Aside from the special cases handled above, accessors are considered
+      // regular methods...
+    }
+
     // Infer non-Escapable results.
     if (isDiagnosedNonEscapable(getResultOrYield())) {
-      if (hasImplicitSelfParam()) {
-        // Methods and accessors that return or yield a non-Escapable value.
-        inferNonEscapableResultOnSelf();
-        return;
-      }
       if (isInit() && isImplicitOrSIL()) {
         inferImplicitInit();
-        return;
+      } else if (hasImplicitSelfParam()) {
+        // Methods that return a non-Escapable value - single parameter
+        // default rule.
+        inferNonEscapableResultOnSelf();
+      } else {
+        // Regular functions and initializers that return a non-Escapable value
+        // - single parameter default rule.
+        inferNonEscapableResultOnParam();
       }
-      // Regular functions and initializers that return a non-Escapable value.
-      inferNonEscapableResultOnParam();
-      return;
     }
 
-    // Infer mutating methods.
-    if (hasImplicitSelfParam()) {
-      if (isDiagnosedNonEscapable(dc->getSelfTypeInContext())) {
-        assert(!isInit() && "class initializers have Escapable self");
-        auto *selfDecl = afd->getImplicitSelfDecl();
-        if (selfDecl->isInOut()) {
-          // Mutating methods (excluding initializers)
-          inferMutatingSelf(selfDecl);
-          return;
-        }
-      }
-    }
-    // Infer inout parameters.
+    // Infer mutating non-Escapable methods (excluding initializers) -
+    // `inout` parameter default rule.
+    inferMutatingSelf();
+
+    // Infer inout parameters - `inout` parameter default rule.
     inferInoutParams();
   }
 
-  // Infer method dependence: result depends on self. This includes _modify.
-  void inferNonEscapableResultOnSelf() {
-    Type selfTypeInContext = dc->getSelfTypeInContext();
-    if (selfTypeInContext->hasError()) {
-      return;
-    }
-    bool nonEscapableSelf = isDiagnosedNonEscapable(selfTypeInContext);
-
-    // Avoid diagnosing inference on mutating methods when 'self' is
-    // non-Escapable. The inout 'self' also needs an inferred dependence on
-    // itself. This will be diagnosed when checking for missing dependencies.
-    if (nonEscapableSelf && afd->getImplicitSelfDecl()->isInOut()) {
-      if (auto accessor = dyn_cast<AccessorDecl>(afd)) {
-        inferMutatingAccessor(accessor);
-      }
+  // Infer dependence for an accessor whose non-escapable result depends on
+  // self. This includes _read and _modify.
+  //
+  // Any accessors not handled here will be handled like a normal method.
+  void inferAccessor(AccessorDecl *accessor) {
+    if (!hasImplicitSelfParam()) {
+      // global accessors have no 'self'.
       return;
     }
-
-    // Methods with parameters only apply to lazy inference.
-    if (!useLazyInference() && afd->getParameters()->size() > 0) {
-      return;
+    bool nonEscapableSelf = isDiagnosedNonEscapable(dc->getSelfTypeInContext());
+    if (nonEscapableSelf && accessor->getImplicitSelfDecl()->isInOut()) {
+      // First, infer the dependency of the inout non-Escapable 'self'. This may
+      // result in two inferred dependencies for accessors.
+      inferMutatingAccessor(accessor);
     }
-    if (!nonEscapableSelf && isBitwiseCopyable(selfTypeInContext, ctx)) {
-      diagnose(returnLoc,
-               diag::lifetime_dependence_cannot_infer_bitwisecopyable,
-               diagnosticQualifier(), "self");
+    // Handle synthesized wrappers...
+    if (!isImplicitOrSIL() && !useLazyInference())
       return;
+
+    // Infer the result dependency of the result or yielded value on 'self'
+    // based on the kind of accessor called by this wrapper accessor.
+    if (auto dependenceKind = getImplicitAccessorResultDependence(accessor)) {
+      depBuilder.inferDependency(resultIndex, selfIndex, *dependenceKind);
     }
-    if (!useLazyInference()) {
-      // Do not infer LifetimeDependenceKind::Inherit unless this is an implicit
-      // getter, which simply returns a stored property.
-      if (nonEscapableSelf && !isImplicitOrSIL()) {
-        diagnose(returnLoc, diag::lifetime_dependence_cannot_infer_kind,
-                 diagnosticQualifier(), "self");
+  }
+
+  // Infer a mutating accessor's non-Escapable 'self' dependencies.
+  void inferMutatingAccessor(AccessorDecl *accessor) {
+    switch (accessor->getAccessorKind()) {
+    case AccessorKind::Read:
+    case AccessorKind::Read2:
+    case AccessorKind::Modify:
+    case AccessorKind::Modify2:
+      // '_read' and '_modify' are inferred like regular methods. The yielded
+      // value depends on the single 'self' parameter. Additionally, '_modify'
+      // infers 'self' as an 'inout' parameter.
+      //
+      // The caller of _modify will ensure that the modified 'self', passed as
+      // 'inout', depends on any value stored to the yielded address.
+      //
+      // Note that the AST generates a _modify for stored properties even though
+      // it won't be emitted.
+      break;
+    case AccessorKind::Set: {
+      const unsigned newValIdx = 0;
+      auto *afd = cast<AbstractFunctionDecl>(decl);
+      auto *param = afd->getParameters()->get(newValIdx);
+      Type paramTypeInContext =
+        afd->mapTypeIntoContext(param->getInterfaceType());
+      if (paramTypeInContext->hasError()) {
         return;
       }
+      depBuilder.inferInoutDependency(selfIndex);
+
+      // The 'newValue' dependence kind must match the getter's dependence kind
+      // because the generated '_modify' accessor composes the getter's result
+      // with the setter's 'newValue'. In particular, if the getter's result is
+      // Escapable then the getter does not have any lifetime dependency, so the
+      // setter cannot depend on 'newValue'.
+      if (!paramTypeInContext->isEscapable()) {
+        depBuilder.inferDependency(selfIndex, newValIdx,
+                                   LifetimeDependenceKind::Inherit);
+      }
+      break;
     }
-    auto kind = inferLifetimeDependenceKindFromType(selfTypeInContext);
-    auto selfOwnership = afd->getImplicitSelfDecl()->getValueOwnership();
-    if (!isCompatibleWithOwnership(kind, selfTypeInContext, selfOwnership)) {
-      diagnose(returnLoc,
-               diag::lifetime_dependence_cannot_infer_scope_ownership,
-               "self", diagnosticQualifier());
-      return;
+    case AccessorKind::MutableAddress:
+      if (useLazyInference()) {
+        // Assume that a mutating method does not depend on its parameters.
+        // Currently only for backward interface compatibility. Even though this
+        // is the only useful dependence (a borrow of self is possible but not
+        // useful), explicit annotation is required for now to confirm that the
+        // mutated self cannot depend on anything stored at this address.
+        depBuilder.inferInoutDependency(selfIndex);
+      }
+      break;
+    default:
+      // Unknown mutating accessor.
+      break;
     }
-    pushDeps(createDeps(resultIndex).add(selfIndex, kind));
   }
 
-  // Infer implicit initialization. The dependence kind can be inferred, similar
-  // to an implicit setter, because the implementation is simply an assignment
-  // to stored property.
+  // Implicit accessors must be consistent with the accessor that they
+  // wrap. Otherwise, the sythesized implementation will report a diagnostic
+  // error.
+  std::optional<LifetimeDependenceKind>
+  getImplicitAccessorResultDependence(AccessorDecl *accessor) {
+    if (!isDiagnosedNonEscapable(getResultOrYield()))
+      return std::nullopt;
+
+    std::optional<AccessorKind> wrappedAccessorKind = std::nullopt;
+    switch (accessor->getAccessorKind()) {
+    case AccessorKind::Read:
+    case AccessorKind::Read2:
+    case AccessorKind::Modify:
+    case AccessorKind::Modify2:
+      // read/modify are syntesized as calls to the getter.
+      wrappedAccessorKind = AccessorKind::Get;
+      break;
+    case AccessorKind::Get:
+      // getters are synthesized as access to a stored property.
+      break;
+    default:
+      // Unknown synthesized accessor.
+      // Setters are handled in inferMutatingAccessor() because they don't
+      // return a value.
+      return std::nullopt;
+    }
+    if (wrappedAccessorKind) {
+      auto *var = cast<AbstractStorageDecl>(accessor->getStorage());
+      for (auto *wrappedAccessor : var->getAllAccessors()) {
+        if (wrappedAccessor->isImplicit())
+          continue;
+        if (wrappedAccessor->getAccessorKind() == wrappedAccessorKind) {
+          if (auto deps = wrappedAccessor->getLifetimeDependencies()) {
+            for (auto &dep : *deps) {
+              if (dep.getTargetIndex() != resultIndex)
+                continue;
+              if (dep.checkInherit(selfIndex))
+                return LifetimeDependenceKind::Inherit;
+              if (dep.checkScope(selfIndex))
+                return LifetimeDependenceKind::Scope;
+            }
+          }
+        }
+      }
+    }
+    // Either a Get or Modify without any wrapped accessor. Handle these like a
+    // read of the stored property.
+    return inferLifetimeDependenceKind(accessor->getImplicitSelfDecl());
+  }
+
+  // Infer implicit initialization. A non-Escapable initializer parameter can
+  // always be inferred, similar to an implicit setter, because the
+  // implementation is simply an assignment to stored property. Escapable
+  // parameters are ambiguous: they may either be borrowed or
+  // non-dependent. non-Escapable types often have incidental integer fields
+  // that are unrelated to lifetime. Avoid inferring any dependency on Escapable
+  // parameters unless it is the (unambiguously borrowed) sole parameter.
   void inferImplicitInit() {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     if (afd->getParameters()->size() == 0) {
       // Empty ~Escapable types can be implicitly initialized without any
       // dependencies. In SIL, implicit initializers become explicit. Set
@@ -852,30 +1273,97 @@ class LifetimeDependenceChecker {
       performedDiagnostics = true;
       return;
     }
-    auto targetDeps = createDeps(resultIndex);
+    TargetDeps *resultDeps = depBuilder.getInferredTargetDeps(resultIndex);
+    if (!resultDeps)
+      return; // .sil implicit initializers may have been annotated.
+
     unsigned paramIndex = 0;
     for (auto *param : *afd->getParameters()) {
       SWIFT_DEFER { paramIndex++; };
       Type paramTypeInContext =
         afd->mapTypeIntoContext(param->getInterfaceType());
       if (paramTypeInContext->hasError()) {
+        return;
+      }
+      if (!paramTypeInContext->isEscapable()) {
+        // An implicitly initialized non-Escapable value always copies its
+        // dependency.
+        resultDeps->addIfNew(paramIndex, LifetimeDependenceKind::Inherit);
         continue;
       }
-      auto kind = inferLifetimeDependenceKindFromType(paramTypeInContext);
-      auto paramOwnership = param->getValueOwnership();
-      if (!isCompatibleWithOwnership(kind, paramTypeInContext, paramOwnership))
-      {
+      if (afd->getParameters()->size() > 1 && !useLazyInference()) {
+        diagnose(param->getLoc(),
+                 diag::lifetime_dependence_cannot_infer_implicit_init);
+        return;
+      }
+      // A single Escapable parameter must be borrowed.
+      auto kind = inferLifetimeDependenceKind(param);
+      if (!kind) {
         diagnose(returnLoc,
                  diag::lifetime_dependence_cannot_infer_scope_ownership,
                  param->getParameterName().str(), diagnosticQualifier());
-        continue;
       }
-      targetDeps = std::move(targetDeps).add(paramIndex, kind);
+      resultDeps->addIfNew(paramIndex, LifetimeDependenceKind::Scope);
     }
-    pushDeps(std::move(targetDeps));
+  }
+
+  // Infer method dependence of result on self for methods, getters, and _modify
+  // accessors. Implements the single-parameter rule for methods and accessors
+  // accessors (ignoring the subscript index parameter).
+  void inferNonEscapableResultOnSelf() {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
+
+    TargetDeps *resultDeps = depBuilder.getInferredTargetDeps(resultIndex);
+    if (!resultDeps)
+      return;
+
+    bool nonEscapableSelf = isDiagnosedNonEscapable(dc->getSelfTypeInContext());
+    // Do not infer the result's dependence when the method is mutating and
+    // 'self' is non-Escapable. Independently, a missing dependence on inout
+    // 'self' will be diagnosed. Since an explicit annotation will be needed for
+    // 'self', we also require the method's result to have an explicit
+    // annotation.
+    if (nonEscapableSelf && afd->getImplicitSelfDecl()->isInOut()) {
+      return;
+    }
+    // Methods with parameters only apply to lazy inference. This does not
+    // include accessors because a subscript's index is assumed not to be the
+    // source of the result's dependency.
+    if (!isa<AccessorDecl>(afd) && !useLazyInference()
+        && afd->getParameters()->size() > 0) {
+      return;
+    }
+    if (!useLazyInference() && !isImplicitOrSIL()) {
+      // Require explicit @_lifetime(borrow self) for UnsafePointer-like self.
+      if (!nonEscapableSelf
+          && isBitwiseCopyable(dc->getSelfTypeInContext(), ctx)) {
+        diagnose(returnLoc,
+                 diag::lifetime_dependence_cannot_infer_bitwisecopyable,
+                 diagnosticQualifier(), "self");
+        return;
+      }
+      // Require explicit @_lifetime(copy or borrow) for non-Escapable self.
+      if (nonEscapableSelf) {
+        diagnose(returnLoc, diag::lifetime_dependence_cannot_infer_kind,
+                 diagnosticQualifier(), "self");
+        return;
+      }
+    }
+    // Infer based on ownership if possible for either explicit accessors or
+    // methods as long as they pass preceding ambiguity checks.
+    auto kind = inferLifetimeDependenceKind(afd->getImplicitSelfDecl());
+    if (!kind) {
+      // Special diagnostic for an attempt to depend on a consuming parameter.
+      diagnose(returnLoc,
+               diag::lifetime_dependence_cannot_infer_scope_ownership,
+               "self", diagnosticQualifier());
+      return;
+    }
+    resultDeps->addIfNew(selfIndex, *kind);
   }
 
   // Infer result dependence on a function or intitializer parameter.
+  // Implements the single-parameter rule for functions.
   //
   // Note: for implicit initializers with parameters, consider inferring
   // Inherit dependency for each non-Escapable parameter. This would be
@@ -884,6 +1372,7 @@ class LifetimeDependenceChecker {
   // inference if any exist, infer scoped dependency, or infer no
   // dependency. Implicit setters for Escapable properties are not inferred.
   void inferNonEscapableResultOnParam() {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     // This is only called when there is no 'self' argument that can be the
     // source of a dependence.
     assert(!hasImplicitSelfParam());
@@ -891,6 +1380,9 @@ class LifetimeDependenceChecker {
     if (useLazyInference()) {
       return lazillyInferNonEscapableResultOnParam();
     }
+    TargetDeps *resultDeps = depBuilder.getInferredTargetDeps(resultIndex);
+    if (!resultDeps)
+      return;
 
     // Strict inference only handles a single escapable parameter,
     // which is an unambiguous borrow dependence.
@@ -919,20 +1411,23 @@ class LifetimeDependenceChecker {
       return;
     }
     auto kind = LifetimeDependenceKind::Scope;
-    auto paramOwnership = param->getValueOwnership();
-    if (!isCompatibleWithOwnership(kind, paramTypeInContext, paramOwnership))
-    {
+    if (!isCompatibleWithOwnership(kind, param)) {
       diagnose(returnLoc,
                diag::lifetime_dependence_cannot_infer_scope_ownership,
                param->getParameterName().str(), diagnosticQualifier());
       return;
     }
-    pushDeps(createDeps(resultIndex).add(/*paramIndex*/ 0, kind));
+    resultDeps->addIfNew(/*paramIndex*/ 0, kind);
   }
 
   // Lazy inference for .swiftinterface backward compatibility and
   // experimentation. Inference cases can be added but not removed.
   void lazillyInferNonEscapableResultOnParam() {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
+    TargetDeps *resultDeps = depBuilder.getInferredTargetDeps(resultIndex);
+    if (!resultDeps)
+      return;
+
     std::optional<unsigned> candidateParamIndex;
     std::optional<LifetimeDependenceKind> candidateLifetimeKind;
     unsigned paramIndex = 0;
@@ -953,10 +1448,8 @@ class LifetimeDependenceChecker {
         }
       }
 
-      candidateLifetimeKind =
-        inferLifetimeDependenceKindFromType(paramTypeInContext);
-      if (!isCompatibleWithOwnership(
-            *candidateLifetimeKind, paramTypeInContext, paramOwnership)) {
+      candidateLifetimeKind = inferLifetimeDependenceKind(param);
+      if (!candidateLifetimeKind) {
         continue;
       }
       if (candidateParamIndex) {
@@ -973,76 +1466,75 @@ class LifetimeDependenceChecker {
                diagnosticQualifier());
       return;
     }
-    pushDeps(createDeps(resultIndex).add(*candidateParamIndex,
-                                         *candidateLifetimeKind));
+    resultDeps->addIfNew(*candidateParamIndex, *candidateLifetimeKind);
   }
-  
+
   // Infer a mutating 'self' dependency when 'self' is non-Escapable and the
   // result is 'void'.
-  void inferMutatingSelf(ParamDecl *selfDecl) {
-    // Handle implicit setters before diagnosing mutating methods. This
-    // does not include global accessors, which have no implicit 'self'.
-    if (auto accessor = dyn_cast<AccessorDecl>(afd)) {
-      inferMutatingAccessor(accessor);
+  void inferMutatingSelf() {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
+    if (!hasImplicitSelfParam())
       return;
-    }
-    if (afd->getParameters()->size() > 0) {
+
+    if (!isDiagnosedNonEscapable(dc->getSelfTypeInContext()))
       return;
-    }
-    pushDeps(createDeps(selfIndex).add(selfIndex,
-                                       LifetimeDependenceKind::Inherit));
-  }
 
-  // Infer a mutating accessor's non-Escapable 'self' dependencies.
-  void inferMutatingAccessor(AccessorDecl *accessor) {
-    if (!isImplicitOrSIL() && !useLazyInference()) {
-      // Explicit setters require explicit lifetime dependencies.
+    assert(!isInit() && "class initializers have Escapable self");
+    auto *selfDecl = afd->getImplicitSelfDecl();
+    if (!selfDecl->isInOut())
       return;
-    }
-    switch (accessor->getAccessorKind()) {
-    case AccessorKind::Read:
-      // An implicit _read accessor is generated when a mutating getter is
-      // declared. Emit the same lifetime dependencies as an implicit _modify.
-    case AccessorKind::Modify:
-    case AccessorKind::Modify2:
-      // A _modify's yielded value depends on self. The _modify dependency in
-      // the opposite direction (self depends on the modified value) is not
-      // recorded. The caller of _modify ensures that the modified 'self',
-      // passed as 'inout', depends on any value stored to the yielded address.
-      //
-      // This is required for stored properties because the AST generates a
-      // _modify for them even though it won't be emitted.
-      pushDeps(createDeps(selfIndex).add(selfIndex,
-                                         LifetimeDependenceKind::Inherit));
-      pushDeps(createDeps(resultIndex).add(selfIndex,
-                                           LifetimeDependenceKind::Scope));
-      break;
-    case AccessorKind::Set: {
-      const unsigned newValIdx = 0;
-      auto *param = afd->getParameters()->get(newValIdx);
-      Type paramTypeInContext =
-        afd->mapTypeIntoContext(param->getInterfaceType());
-      if (paramTypeInContext->hasError()) {
-        return;
-      }
-      auto kind = inferLifetimeDependenceKindFromType(paramTypeInContext);
 
-      pushDeps(createDeps(selfIndex)
-               .add(selfIndex, LifetimeDependenceKind::Inherit)
-               .add(newValIdx, kind));
-      break;
-    }
-    default:
-      // Unknown mutating accessor.
-      break;
-    }
+    // Assume that a mutating method does not depend on its parameters.
+    depBuilder.inferInoutDependency(selfIndex);
   }
 
-  // Infer 'inout' parameter dependency when the only parameter is
-  // non-Escapable.
+  // Infer @_lifetime(param: copy param) for 'inout' non-Escapable parameters.
+  //
+  // This supports the common case in which the user of a non-Escapable type,
+  // such as MutableSpan, wants to modify the span's contents without modifying
+  // the span value itself. It should be possible to use MutableSpan this way
+  // without requiring any knowledge of lifetime annotations. The tradeoff is
+  // that it makes authoring non-Escapable types less safe. For example, a
+  // MutableSpan method could update the underlying unsafe pointer and forget to
+  // declare a dependence on the incoming pointer.
+  //
+  // This also allows programmers to make the easy mistake reassign the inout
+  // parameter to another parameter:
+  //
+  //     func reassign(s: inout MutableSpan<Int>, a: MutableSpan) {
+  //       s = a
+  //     }
   //
-  // This is needed for most generic Builtin functions.
+  // But, even if that case were disallowed, they may derive another
+  // non-Escapable value from an Escapable parameteter:
+  //
+  //     func reassign(s: inout MutableSpan<Int>, a: [Int]) {
+  //       s = a.mutableSpan
+  //     }
+  //
+  // In either case, a diagnostics on the `reassign` function's implementation
+  // will catch the invalid reassignment. The only real danger is when the
+  // implementation is uses unsafe constructs.
+  //
+  // Do not issue any diagnostics. This inference is triggered even when the
+  // feature is disabled!
   void inferInoutParams() {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
+    for (unsigned paramIndex : range(afd->getParameters()->size())) {
+      auto *param = afd->getParameters()->get(paramIndex);
+      if (!isDiagnosedNonEscapable(
+              afd->mapTypeIntoContext(param->getInterfaceType()))) {
+        continue;
+      }
+      if (!param->isInOut())
+        continue;
+
+      depBuilder.inferInoutDependency(paramIndex);
+    }
+  }
+
+  void inferUnambiguousInoutParams() {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     if (afd->getParameters()->size() != 1) {
       return;
     }
@@ -1055,16 +1547,14 @@ class LifetimeDependenceChecker {
           afd->mapTypeIntoContext(param->getInterfaceType()))) {
       return;
     }
-    pushDeps(createDeps(paramIndex).add(paramIndex,
-                                        LifetimeDependenceKind::Inherit));
+    depBuilder.inferInoutDependency(paramIndex);
   }
 
   void inferBuiltin() {
+    auto *afd = cast<AbstractFunctionDecl>(decl);
     // Normal inout parameter inference works for most generic Builtins.
-    inferInoutParams();
-    if (!lifetimeDependencies.empty()) {
-      return;
-    }
+    inferUnambiguousInoutParams();
+
     const DeclName &name = afd->getName();
     if (name.isSpecial()) {
       return;
@@ -1078,28 +1568,54 @@ class LifetimeDependenceChecker {
         ctx.getIdentifier(getBuiltinName(BuiltinValueKind::InjectEnumTag))) {
       // ignore the tag parameter
       const unsigned inoutIdx = 0;
-      pushDeps(createDeps(inoutIdx).add(inoutIdx,
-                                        LifetimeDependenceKind::Inherit));
+      depBuilder.inferInoutDependency(inoutIdx);
     } else if (id ==
         ctx.getIdentifier(
           getBuiltinName(BuiltinValueKind::ConvertUnownedUnsafeToGuaranteed))) {
       const unsigned baseIdx = 0;
       const unsigned inoutIdx = 1;
-      pushDeps(createDeps(inoutIdx)
-               .add(inoutIdx, LifetimeDependenceKind::Inherit)
-               .add(baseIdx, LifetimeDependenceKind::Scope));
+      depBuilder.inferInoutDependency(inoutIdx);
+      depBuilder.inferDependency(inoutIdx, baseIdx,
+                                 LifetimeDependenceKind::Scope);
     }
   }
 };
 
 std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>
-LifetimeDependenceInfo::get(AbstractFunctionDecl *afd) {
-  return LifetimeDependenceChecker(afd).checkFuncDecl();
+LifetimeDependenceInfo::get(ValueDecl *decl) {
+  if (auto *afd = dyn_cast<AbstractFunctionDecl>(decl)) {
+    return LifetimeDependenceChecker(afd).checkFuncDecl();
+  }
+  auto *eed = cast<EnumElementDecl>(decl);
+  return LifetimeDependenceChecker(eed).checkEnumElementDecl();
 }
 
+void LifetimeDependenceInfo::dump() const {
+  llvm::errs() << "target: " << getTargetIndex() << '\n';
+  if (isImmortal()) {
+    llvm::errs() << "  immortal\n";
+  }
+  if (auto scoped = getScopeIndices()) {
+    llvm::errs() << "  scoped: ";
+    scoped->dump();
+  }
+  if (auto inherited = getInheritIndices()) {
+    llvm::errs() << "  inherited: ";
+    inherited->dump();
+  }
+  if (auto addressable = getAddressableIndices()) {
+    llvm::errs() << "  addressable: ";
+    addressable->dump();
+  }
+}
+
+// =============================================================================
+// SIL parsing support
+// =============================================================================
+
 // This implements the logic for SIL type descriptors similar to source-level
-// logic in LifetimeDependenceChecker::checkAttributeEntry(). The SIL context is
-// substantially different from Sema.
+// logic in LifetimeDependenceChecker::initializeAttributeDeps(). The SIL
+// context is substantially different from Sema.
 static std::optional<LifetimeDependenceInfo> checkSILTypeModifiers(
   LifetimeDependentTypeRepr *lifetimeDependentRepr, unsigned targetIndex,
   ArrayRef<SILParameterInfo> params, DeclContext *dc) {
@@ -1119,7 +1635,7 @@ static std::optional<LifetimeDependenceInfo> checkSILTypeModifiers(
       auto loc = descriptor.getLoc();
       auto kind = descriptor.getParsedLifetimeDependenceKind();
 
-      if (kind == ParsedLifetimeDependenceKind::Scope &&
+      if (kind == ParsedLifetimeDependenceKind::Borrow &&
           isConsumedParameterInCallee(paramConvention)) {
         diags.diagnose(loc, diag::lifetime_dependence_cannot_use_kind, "_scope",
                        getStringForParameterConvention(paramConvention));
@@ -1134,7 +1650,7 @@ static std::optional<LifetimeDependenceInfo> checkSILTypeModifiers(
       if (kind == ParsedLifetimeDependenceKind::Inherit) {
         inheritLifetimeParamIndices.set(paramIndexToSet);
       } else {
-        assert(kind == ParsedLifetimeDependenceKind::Scope);
+        assert(kind == ParsedLifetimeDependenceKind::Borrow);
         scopeLifetimeParamIndices.set(paramIndexToSet);
       }
       return false;
@@ -1232,23 +1748,4 @@ LifetimeDependenceInfo::getFromSIL(FunctionTypeRepr *funcRepr,
   return dc->getASTContext().AllocateCopy(lifetimeDependencies);
 }
 
-void LifetimeDependenceInfo::dump() const {
-  llvm::errs() << "target: " << getTargetIndex() << '\n';
-  if (isImmortal()) {
-    llvm::errs() << "  immortal\n";
-  }
-  if (auto scoped = getScopeIndices()) {
-    llvm::errs() << "  scoped: ";
-    scoped->dump();
-  }
-  if (auto inherited = getInheritIndices()) {
-    llvm::errs() << "  inherited: ";
-    inherited->dump();
-  }
-  if (auto addressable = getAddressableIndices()) {
-    llvm::errs() << "  addressable: ";
-    addressable->dump();
-  }
-}
-
 } // namespace swift
diff --git a/lib/AST/LocalArchetypeRequirementCollector.cpp b/lib/AST/LocalArchetypeRequirementCollector.cpp
index 9cf14422884bd..7ccdf504a7cc3 100644
--- a/lib/AST/LocalArchetypeRequirementCollector.cpp
+++ b/lib/AST/LocalArchetypeRequirementCollector.cpp
@@ -135,14 +135,14 @@ GenericSignature swift::buildGenericSignatureWithCapturedEnvironments(
     case GenericEnvironment::Kind::Opaque:
       break;
 
-    case GenericEnvironment::Kind::OpenedExistential: {
+    case GenericEnvironment::Kind::Existential: {
       auto existentialTy = genericEnv->maybeApplyOuterContextSubstitutions(
           genericEnv->getOpenedExistentialType())
               ->mapTypeOutOfContext();
       collector.addOpenedExistential(existentialTy);
       continue;
     }
-    case GenericEnvironment::Kind::OpenedElement: {
+    case GenericEnvironment::Kind::Element: {
       collector.addOpenedElement(
           genericEnv->getOpenedElementShapeClass());
       continue;
@@ -183,9 +183,10 @@ Type MapLocalArchetypesOutOfContext::getInterfaceType(
     ++depth;
   }
 
-  llvm::errs() << "Fell off the end:\n";
-  interfaceTy->dump(llvm::errs());
-  abort();
+  ABORT([&](auto &out) {
+    out << "Fell off the end:\n";
+    interfaceTy->dump(out);
+  });
 }
 
 Type MapLocalArchetypesOutOfContext::operator()(SubstitutableType *type) const {
@@ -213,7 +214,7 @@ Type swift::mapLocalArchetypesOutOfContext(
     GenericSignature baseGenericSig,
     ArrayRef<GenericEnvironment *> capturedEnvs) {
   return type.subst(MapLocalArchetypesOutOfContext(baseGenericSig, capturedEnvs),
-                    MakeAbstractConformanceForGenericType(),
+                    LookUpConformanceInModule(),
                     SubstFlags::PreservePackExpansionLevel |
                     SubstFlags::SubstitutePrimaryArchetypes |
                     SubstFlags::SubstituteLocalArchetypes);
@@ -266,10 +267,10 @@ swift::buildSubstitutionMapWithCapturedEnvironments(
         return mapIntoLocalContext(param, baseDepth, capturedEnvs);
       return Type(type).subst(baseSubMap);
     },
-    [&](CanType origType, Type substType,
-        ProtocolDecl *proto) -> ProtocolConformanceRef {
+    [&](InFlightSubstitution &IFS, Type origType, ProtocolDecl *proto)
+          -> ProtocolConformanceRef {
       if (origType->getRootGenericParam()->getDepth() >= baseDepth)
-        return ProtocolConformanceRef::forAbstract(substType, proto);
-      return baseSubMap.lookupConformance(origType, proto);
+        return ProtocolConformanceRef::forAbstract(origType.subst(IFS), proto);
+      return baseSubMap.lookupConformance(origType->getCanonicalType(), proto);
     });
 }
diff --git a/lib/AST/Module.cpp b/lib/AST/Module.cpp
index f8ed0c23c6850..044d5769dd1e5 100644
--- a/lib/AST/Module.cpp
+++ b/lib/AST/Module.cpp
@@ -68,6 +68,7 @@
 #include "llvm/Support/SaveAndRestore.h"
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/Support/raw_ostream.h"
+#include <optional>
 
 using namespace swift;
 
@@ -783,6 +784,7 @@ ModuleDecl::ModuleDecl(Identifier name, ASTContext &ctx,
   Bits.ModuleDecl.AllowNonResilientAccess = 0;
   Bits.ModuleDecl.SerializePackageEnabled = 0;
   Bits.ModuleDecl.StrictMemorySafety = 0;
+  Bits.ModuleDecl.DeferredCodeGen = 0;
 
   // Populate the module's files.
   SmallVector<FileUnit *, 2> files;
@@ -821,6 +823,16 @@ ImplicitImportList ModuleDecl::getImplicitImports() const {
                            {});
 }
 
+const AccessNotesFile *ModuleDecl::getAccessNotes() const {
+  // Only the main module has access notes.
+  if (!isMainModule())
+    return nullptr;
+
+  auto &ctx = getASTContext();
+  return evaluateOrDefault(ctx.evaluator, LoadAccessNotesRequest{&ctx},
+                           nullptr);
+}
+
 SourceFile *ModuleDecl::getSourceFileContainingLocation(SourceLoc loc) {
   if (loc.isInvalid())
     return nullptr;
@@ -847,49 +859,6 @@ SourceFile *ModuleDecl::getSourceFileContainingLocation(SourceLoc loc) {
   return nullptr;
 }
 
-std::pair<unsigned, SourceLoc>
-ModuleDecl::getOriginalLocation(SourceLoc loc) const {
-  assert(loc.isValid());
-
-  SourceManager &SM = getASTContext().SourceMgr;
-  unsigned bufferID = SM.findBufferContainingLoc(loc);
-
-  SourceLoc startLoc = loc;
-  unsigned startBufferID = bufferID;
-  while (const GeneratedSourceInfo *info =
-             SM.getGeneratedSourceInfo(bufferID)) {
-    switch (info->kind) {
-#define MACRO_ROLE(Name, Description)  \
-    case GeneratedSourceInfo::Name##MacroExpansion:
-#include "swift/Basic/MacroRoles.def"
-    {
-      // Location was within a macro expansion, return the expansion site, not
-      // the insertion location.
-      if (info->attachedMacroCustomAttr) {
-        loc = info->attachedMacroCustomAttr->getLocation();
-      } else {
-        ASTNode expansionNode = ASTNode::getFromOpaqueValue(info->astNode);
-        loc = expansionNode.getStartLoc();
-      }
-      bufferID = SM.findBufferContainingLoc(loc);
-      break;
-    }
-    case GeneratedSourceInfo::DefaultArgument:
-      // No original location as it's not actually in any source file
-    case GeneratedSourceInfo::ReplacedFunctionBody:
-      // There's not really any "original" location for locations within
-      // replaced function bodies. The body is actually different code to the
-      // original file.
-    case GeneratedSourceInfo::PrettyPrinted:
-    case GeneratedSourceInfo::AttributeFromClang:
-      // No original location, return the original buffer/location
-      return {startBufferID, startLoc};
-    }
-  }
-
-  return {bufferID, loc};
-}
-
 ArrayRef<SourceFile *>
 PrimarySourceFilesRequest::evaluate(Evaluator &evaluator,
                                     ModuleDecl *mod) const {
@@ -1075,6 +1044,20 @@ void ModuleDecl::lookupImportedSPIGroups(
   FORWARD(lookupImportedSPIGroups, (importedModule, spiGroups));
 }
 
+bool ModuleDecl::isModuleImportedPreconcurrency(
+    const ModuleDecl *importedModule) const {
+  for (const FileUnit *file : getFiles()) {
+    if (file->isModuleImportedPreconcurrency(importedModule))
+      return true;
+
+    if (auto *synth = file->getSynthesizedFile()) {
+      if (synth->isModuleImportedPreconcurrency(importedModule))
+        return true;
+    }
+  }
+  return false;
+}
+
 void ModuleDecl::lookupAvailabilityDomains(
     Identifier identifier,
     llvm::SmallVectorImpl<AvailabilityDomain> &results) const {
@@ -1431,11 +1414,11 @@ SourceFile::getExternalRawLocsForDecl(const Decl *D) const {
   bool InGeneratedBuffer =
       !SM.rangeContainsTokenLoc(SM.getRangeForBuffer(BufferID), MainLoc);
   if (InGeneratedBuffer) {
-    unsigned UnderlyingBufferID;
-    std::tie(UnderlyingBufferID, MainLoc) =
-        D->getModuleContext()->getOriginalLocation(MainLoc);
-    if (BufferID != UnderlyingBufferID)
-      return std::nullopt;
+    if (auto R = getUnexpandedMacroRange(SM, MainLoc)) {
+      if (BufferID != SM.findBufferContainingLoc(R.Start))
+        return std::nullopt;
+      MainLoc = R.Start;
+    }
   }
 
   auto setLoc = [&](ExternalSourceLocs::RawLoc &RawLoc, SourceLoc Loc) {
@@ -1862,7 +1845,7 @@ StringRef ModuleDecl::ReverseFullNameIterator::operator*() const {
     return swiftModule->getRealName().str();
 
   auto *clangModule =
-      static_cast<const clang::Module *>(current.get<const void *>());
+      static_cast<const clang::Module *>(cast<const void *>(current));
   if (!clangModule->isSubModule() && clangModule->Name == "std")
     return "CxxStdlib";
   return clangModule->Name;
@@ -1873,13 +1856,13 @@ ModuleDecl::ReverseFullNameIterator::operator++() {
   if (!current)
     return *this;
 
-  if (current.is<const ModuleDecl *>()) {
+  if (isa<const ModuleDecl *>(current)) {
     current = nullptr;
     return *this;
   }
 
   auto *clangModule =
-      static_cast<const clang::Module *>(current.get<const void *>());
+      static_cast<const clang::Module *>(cast<const void *>(current));
   if (clangModule->Parent)
     current = clangModule->Parent;
   else
@@ -2017,6 +2000,10 @@ bool ModuleDecl::isStdlibModule() const {
   return !getParent() && getName() == getASTContext().StdlibModuleName;
 }
 
+bool ModuleDecl::isCxxModule() const {
+  return !getParent() && getName() == getASTContext().Id_Cxx;
+}
+
 bool ModuleDecl::isConcurrencyModule() const {
   return !getParent() && getName() == getASTContext().Id_Concurrency;
 }
@@ -2411,28 +2398,41 @@ void ModuleDecl::findDeclaredCrossImportOverlaysTransitive(
   if (auto *clangModule = getUnderlyingModuleIfOverlay())
     worklist.push_back(clangModule);
 
+  auto addOverlay = [&](Identifier overlay) {
+    // We don't present non-underscored overlays as part of the underlying
+    // module, so ignore them.
+    if (!overlay.hasUnderscoredNaming())
+      return;
+
+    ModuleDecl *overlayMod =
+        getASTContext().getModuleByIdentifier(overlay);
+    if (!overlayMod && overlayMod != this)
+      return;
+
+    if (seen.insert(overlayMod).second) {
+      overlayModules.push_back(overlayMod);
+      worklist.push_back(overlayMod);
+      if (auto *clangModule = overlayMod->getUnderlyingModuleIfOverlay())
+        worklist.push_back(clangModule);
+    }
+  };
+
   while (!worklist.empty()) {
     ModuleDecl *current = worklist.back();
     worklist.pop_back();
+
+    if (current->isStdlibModule()) {
+      for (auto overlay : getASTContext().StdlibOverlayNames) {
+        addOverlay(overlay);
+      }
+    }
+
     for (auto &pair: current->declaredCrossImports) {
       Identifier &bystander = std::get<0>(pair);
       for (auto *file: std::get<1>(pair)) {
         auto overlays = file->getOverlayModuleNames(current, unused, bystander);
         for (Identifier overlay: overlays) {
-          // We don't present non-underscored overlays as part of the underlying
-          // module, so ignore them.
-          if (!overlay.hasUnderscoredNaming())
-            continue;
-          ModuleDecl *overlayMod =
-              getASTContext().getModuleByName(overlay.str());
-          if (!overlayMod)
-            continue;
-          if (seen.insert(overlayMod).second) {
-            overlayModules.push_back(overlayMod);
-            worklist.push_back(overlayMod);
-            if (auto *clangModule = overlayMod->getUnderlyingModuleIfOverlay())
-              worklist.push_back(clangModule);
-          }
+          addOverlay(overlay);
         }
       }
     }
@@ -2469,6 +2469,12 @@ ModuleDecl::getDeclaringModuleAndBystander() {
   if (!hasUnderscoredNaming())
     return *(declaringModuleAndBystander = {nullptr, Identifier()});
 
+  // If this is one of the stdlib overlays, indicate as much.
+  auto &ctx = getASTContext();
+  if (llvm::is_contained(ctx.StdlibOverlayNames, getRealName()))
+    return *(declaringModuleAndBystander = { ctx.getStdlibModule(),
+                                             Identifier() });
+
   // Search the transitive set of imported @_exported modules to see if any have
   // this module as their overlay.
   SmallPtrSet<ModuleDecl *, 16> seen;
@@ -2548,7 +2554,8 @@ bool ModuleDecl::getRequiredBystandersIfCrossImportOverlay(
   auto *clangModule = declaring->getUnderlyingModuleIfOverlay();
   auto current = std::make_pair(this, Identifier());
   while ((current = current.first->getDeclaringModuleAndBystander()).first) {
-    bystanderNames.push_back(current.second);
+    if (!current.second.empty())
+      bystanderNames.push_back(current.second);
     if (current.first == declaring || current.first == clangModule)
       return true;
   }
@@ -2702,6 +2709,11 @@ void
 SourceFile::setImports(ArrayRef<AttributedImport<ImportedModule>> imports) {
   assert(!Imports && "Already computed imports");
   Imports = getASTContext().AllocateCopy(imports);
+  if (getASTContext().LangOpts.DumpSourceFileImports) {
+    llvm::errs() << "imports for " << getFilename() << ":\n";
+    for (auto Import : imports)
+      llvm::errs() << "\t" << Import.module.importedModule->getName() << "\n";
+  }
 }
 
 std::optional<AttributedImport<ImportedModule>>
@@ -2916,6 +2928,7 @@ bool SourceFile::hasTestableOrPrivateImport(
       });
 }
 
+// FIXME: This should probably be requestified.
 RestrictedImportKind SourceFile::getRestrictedImportKind(const ModuleDecl *module) const {
   auto &imports = getASTContext().getImportCache();
   RestrictedImportKind importKind = RestrictedImportKind::MissingImport;
@@ -3003,7 +3016,9 @@ SourceFile::getImportAccessLevel(const ModuleDecl *targetModule) const {
   // they are recommended over indirect imports.
   if ((!restrictiveImport.has_value() ||
        restrictiveImport->accessLevel < AccessLevel::Public) &&
-     imports.isImportedBy(targetModule, getParentModule()))
+      !(restrictiveImport &&
+        restrictiveImport->module.importedModule->isClangHeaderImportModule()) &&
+      imports.isImportedBy(targetModule, getParentModule()))
     return std::nullopt;
 
   return restrictiveImport;
@@ -3076,6 +3091,20 @@ void SourceFile::lookupImportedSPIGroups(
   }
 }
 
+bool SourceFile::isModuleImportedPreconcurrency(
+    const ModuleDecl *importedModule) const {
+  auto &imports = getASTContext().getImportCache();
+  for (auto &import : *Imports) {
+    if (import.options.contains(ImportFlags::Preconcurrency) &&
+        (importedModule == import.module.importedModule ||
+         imports.isImportedByViaSwiftOnly(importedModule,
+                                          import.module.importedModule))) {
+      return true;
+    }
+  }
+  return false;
+}
+
 bool shouldImplicitImportAsSPI(ArrayRef<Identifier> spiGroups) {
   for (auto group : spiGroups) {
     if (group.empty())
@@ -3109,7 +3138,7 @@ bool SourceFile::isImportedAsSPI(const ValueDecl *targetDecl) const {
   return false;
 }
 
-bool ModuleDecl::isImportedAsSPI(const SpecializeAttr *attr,
+bool ModuleDecl::isImportedAsSPI(const AbstractSpecializeAttr *attr,
                                  const ValueDecl *targetDecl) const {
   auto declSPIGroups = attr->getSPIGroups();
   if (shouldImplicitImportAsSPI(declSPIGroups))
@@ -3829,6 +3858,12 @@ bool SourceFile::FileIDStr::matches(const SourceFile *file) const {
          fileName == llvm::sys::path::filename(file->getFilename());
 }
 
+std::optional<DefaultIsolation> SourceFile::getDefaultIsolation() const {
+  auto &ctx = getASTContext();
+  return evaluateOrDefault(
+      ctx.evaluator, DefaultIsolationInSourceFileRequest{this}, std::nullopt);
+}
+
 namespace {
 class LocalTypeDeclCollector : public ASTWalker {
   SmallVectorImpl<TypeDecl *> &results;
@@ -4017,7 +4052,7 @@ StringRef LoadedFile::getFilename() const {
 
 static const clang::Module *
 getClangModule(llvm::PointerUnion<const ModuleDecl *, const void *> Union) {
-  return static_cast<const clang::Module *>(Union.get<const void *>());
+  return static_cast<const clang::Module *>(cast<const void *>(Union));
 }
 
 StringRef ModuleEntity::getName(bool useRealNameIfAliased) const {
@@ -4065,7 +4100,7 @@ const ModuleDecl* ModuleEntity::getAsSwiftModule() const {
 
 const clang::Module* ModuleEntity::getAsClangModule() const {
   assert(!Mod.isNull());
-  if (Mod.is<const ModuleDecl*>())
+  if (isa<const ModuleDecl *>(Mod))
     return nullptr;
   return getClangModule(Mod);
 }
@@ -4181,282 +4216,3 @@ version::Version ModuleDecl::getLanguageVersionBuiltWith() const {
 
   return version::Version();
 }
-
-//===----------------------------------------------------------------------===//
-//                            MARK: SwiftSettings
-//===----------------------------------------------------------------------===//
-
-static llvm::cl::opt<bool> AllowForDuplicateSwiftSettings(
-    "swift-settings-allow-duplicates",
-    llvm::cl::desc("Option that allows for duplicate SwiftSettings. Just for "
-                   "compiler testing"),
-    llvm::cl::Hidden);
-
-namespace {
-
-enum class SwiftSettingKind {
-  Unknown = 0,
-  DefaultIsolation,
-
-  LastKind = DefaultIsolation,
-};
-
-struct SwiftSettingsWalker : ASTWalker {
-  SourceFile &sf;
-  ASTContext &ctx;
-  SourceFileLangOptions result;
-
-  SmallVector<Expr *, 1> swiftSettingIndexToOriginalExprMap;
-
-  SwiftSettingsWalker(SourceFile &sf, ASTContext &ctx)
-      : sf(sf), ctx(ctx), result() {
-    // NOTE: We do not store a value for Unknown.
-    for (unsigned i : range(unsigned(SwiftSettingKind::LastKind))) {
-      (void)i;
-      swiftSettingIndexToOriginalExprMap.push_back(nullptr);
-    }
-  }
-
-  Expr *&getOriginalSwiftSetting(SwiftSettingKind kind) {
-    assert(kind != SwiftSettingKind::Unknown);
-    return swiftSettingIndexToOriginalExprMap[unsigned(kind) - 1];
-  }
-
-  /// Given a specific CallExpr, pattern matches the CallExpr's first argument
-  /// to validate it is MainActor.self. Returns CanType() if the CallExpr has
-  /// multiple parameters or if its first parameter is not a MainActor.self.
-  ///
-  /// This is used when pattern matching against
-  /// .defaultIsolation(MainActor.self).
-  CanType patternMatchDefaultIsolationMainActor(CallExpr *callExpr);
-
-  /// Validates that macroExpr is a well formed "SwiftSettings" macro. Returns
-  /// true if we can process it and false otherwise.
-  bool isSwiftSettingsMacroExpr(MacroExpansionExpr *macroExpr);
-
-  /// Given a specific \p arg to a SwiftSettings macro, attempt to lookup the
-  /// static method on SwiftSetting. Returns nullptr on failure.
-  std::optional<std::pair<CallExpr *, FuncDecl *>>
-  getSwiftSettingArgDecl(Argument arg);
-
-  PreWalkResult<Expr *> walkToExprPre(Expr *expr) override {
-    // First see if we have a "SwiftSettings" macro expansion expr. If we do not
-    // there is no further work to do... just continue.
-    auto *macroExpr = dyn_cast<MacroExpansionExpr>(expr);
-    if (!macroExpr || !isSwiftSettingsMacroExpr(macroExpr))
-      return Action::SkipChildren(expr);
-
-    // Ok, we found our SwiftSettingsMacro. Lets start pattern matching.
-    bool emittedDiagnostic = false;
-    for (auto arg : *macroExpr->getArgs()) {
-      // If we did not find any macro, we emit an unknown macro error. We use
-      // SWIFT_DEFER so we can use early exits below and ensure we always
-      // perform the check.
-      bool foundValidArg = false;
-      SWIFT_DEFER {
-        if (!foundValidArg) {
-          emittedDiagnostic = true;
-          ctx.Diags.diagnose(arg.getStartLoc(),
-                             diag::swift_settings_invalid_setting);
-        }
-      };
-
-      auto calleeFuncDecl = getSwiftSettingArgDecl(arg);
-      if (!calleeFuncDecl)
-        continue;
-      CallExpr *callExpr;
-      FuncDecl *funcDecl;
-      std::tie(callExpr, funcDecl) = *calleeFuncDecl;
-
-      auto kind =
-          llvm::StringSwitch<SwiftSettingKind>(
-              funcDecl->getBaseIdentifier().get())
-              .Case("defaultIsolation", SwiftSettingKind::DefaultIsolation)
-              .Default(SwiftSettingKind::Unknown);
-      switch (kind) {
-      case SwiftSettingKind::Unknown:
-        // Emit error.
-        continue;
-
-      case SwiftSettingKind::DefaultIsolation:
-        auto *&expr =
-            getOriginalSwiftSetting(SwiftSettingKind::DefaultIsolation);
-
-        // If we already have an expr, emit an error and continue.
-        if (!AllowForDuplicateSwiftSettings && expr) {
-          ctx.Diags.diagnose(arg.getStartLoc(),
-                             diag::swift_settings_duplicate_setting);
-          ctx.Diags.diagnose(
-              expr->getLoc(),
-              diag::swift_settings_duplicate_setting_original_loc);
-          foundValidArg = true;
-          continue;
-        }
-
-        // Otherwise, set things up appropriately.
-        if (auto actor = patternMatchDefaultIsolationMainActor(callExpr)) {
-          expr = callExpr;
-          result.defaultIsolation = actor;
-          foundValidArg = true;
-          continue;
-        }
-
-        if (isa<NilLiteralExpr>(callExpr->getArgs()->getExpr(0))) {
-          expr = callExpr;
-          result.defaultIsolation = {Type()};
-          foundValidArg = true;
-          continue;
-        }
-
-        continue;
-      }
-    }
-
-    return Action::SkipChildren(expr);
-  }
-};
-
-} // namespace
-
-bool SwiftSettingsWalker::isSwiftSettingsMacroExpr(
-    MacroExpansionExpr *macroExpr) {
-  // First make sure we actually have a macro with the name SwiftSettings.
-  if (!macroExpr->getMacroName().getBaseName().getIdentifier().is(
-          "SwiftSettings"))
-    return false;
-
-  // Ok, we found a SwiftSettings macro. Perform an unqualified lookup to find
-  // the decl.
-  SmallVector<MacroDecl *, 1> macroDecls;
-  namelookup::forEachPotentialResolvedMacro(
-      sf.getModuleScopeContext(), macroExpr->getMacroName(),
-      MacroRole::Declaration,
-      [&](MacroDecl *decl, const MacroRoleAttr *) -> void {
-        macroDecls.push_back(decl);
-      });
-
-  // If we have multiple macroDecls, we must have some other macro called
-  // SwiftSettings. Let that take precedence and do not emit anything. The
-  // user can always specify Swift.SwiftSettings if needed?
-  if (macroDecls.size() != 1)
-    return false;
-
-  // Ok, we only found one macroDecl. Make sure that it is from the stdlib. If
-  // not, something weird is happening... we can just skip the children.
-  auto *macroDecl = macroDecls.pop_back_val();
-  if (!macroDecl->isStdlibDecl())
-    return false;
-
-  // Validate the form of our macroDef. We use assert instead of ASSERT since we
-  // go through the request evaluator when we call getDefinition().
-#ifndef NDEBUG
-  auto macroDef = macroDecl->getDefinition();
-  assert(macroDef.kind == MacroDefinition::Kind::Builtin &&
-         macroDef.getBuiltinKind() == BuiltinMacroKind::SwiftSettingsMacro &&
-         "SwiftSettings macro from the stdlib that is not the actual builtin "
-         "macro?!");
-#endif
-
-  // We found a good SwiftSettings macro!
-  return true;
-}
-
-std::optional<std::pair<CallExpr *, FuncDecl *>>
-SwiftSettingsWalker::getSwiftSettingArgDecl(Argument arg) {
-  auto *callExpr = dyn_cast<CallExpr>(arg.getExpr());
-  if (!callExpr)
-    return {};
-
-  auto *directCallee =
-      dyn_cast<UnresolvedMemberExpr>(callExpr->getDirectCallee());
-  if (!directCallee)
-    return {};
-
-  // Now lookup our swiftSettingDecl.
-  NominalTypeDecl *swiftSettingsDecl = nullptr;
-  {
-    SmallVector<ValueDecl *, 1> decls;
-    ctx.lookupInSwiftModule("SwiftSetting", decls);
-
-    // We should always have only one decl and it should be a nominal type
-    // decl.
-    if (decls.size() != 1)
-      return {};
-    swiftSettingsDecl = dyn_cast<NominalTypeDecl>(decls.pop_back_val());
-    if (!swiftSettingsDecl)
-      return {};
-  }
-  assert(swiftSettingsDecl);
-
-  // We have our callee, perform qualified name lookup for it on
-  // SwiftSetting.
-  DirectLookupDescriptor lookupDesc{
-      swiftSettingsDecl, directCallee->getName().getFullName(),
-      NominalTypeDecl::LookupDirectFlags::ExcludeMacroExpansions};
-  auto lookup =
-      evaluateOrDefault(ctx.evaluator, DirectLookupRequest{lookupDesc, {}}, {});
-  if (lookup.empty())
-    return {};
-
-  auto *f = dyn_cast<FuncDecl>(lookup.front());
-  if (!f)
-    return {};
-
-  return {{callExpr, f}};
-}
-
-CanType
-SwiftSettingsWalker::patternMatchDefaultIsolationMainActor(CallExpr *callExpr) {
-  // Grab the dot self expr.
-  auto *selfExpr = dyn_cast<DotSelfExpr>(callExpr->getArgs()->getExpr(0));
-  if (!selfExpr)
-    return CanType();
-
-  // Then validate we have something that is MainActor.
-  auto *declRefExpr = dyn_cast<UnresolvedDeclRefExpr>(selfExpr->getSubExpr());
-  if (!declRefExpr ||
-      !declRefExpr->getName().getBaseName().getIdentifier().is("MainActor"))
-    return CanType();
-
-  // Then use unqualified lookup descriptor to find our MainActor.
-  UnqualifiedLookupDescriptor lookupDesc{
-      declRefExpr->getName(), sf.getModuleScopeContext(), SourceLoc(),
-      UnqualifiedLookupFlags::ExcludeMacroExpansions};
-  auto lookup = evaluateOrDefault(ctx.evaluator,
-                                  UnqualifiedLookupRequest{lookupDesc}, {});
-  if (lookup.allResults().empty())
-    return CanType();
-
-  // Then grab our nominal type decl and make sure it is from the concurrency
-  // module.
-  auto *nomDecl =
-      dyn_cast<NominalTypeDecl>(lookup.allResults().front().getValueDecl());
-  if (!nomDecl)
-    return CanType();
-  auto *nomDeclDC = nomDecl->getDeclContext();
-  auto *nomDeclModule = nomDecl->getParentModule();
-  if (!nomDeclDC->isModuleScopeContext() || !nomDeclModule->isConcurrencyModule())
-    return CanType();
-
-  return nomDecl->getDeclaredType()->getCanonicalType();
-}
-
-SourceFileLangOptions
-SourceFileLangOptionsRequest::evaluate(Evaluator &evaluator,
-                                       SourceFile *f) const {
-  SwiftSettingsWalker walker(*f, f->getASTContext());
-
-  if (!f->getASTContext().LangOpts.hasFeature(Feature::SwiftSettings))
-    return walker.result;
-
-  for (auto *decl : f->getTopLevelDecls())
-    decl->walk(walker);
-
-  return walker.result;
-}
-
-SourceFileLangOptions SourceFile::getLanguageOptions() const {
-  auto &eval = getASTContext().evaluator;
-  auto *self = const_cast<SourceFile *>(this);
-  return evaluateOrDefault(eval, SourceFileLangOptionsRequest{self}, {});
-}
diff --git a/lib/AST/ModuleDependencies.cpp b/lib/AST/ModuleDependencies.cpp
index 063493bb92bb3..4df96ab8eac5a 100644
--- a/lib/AST/ModuleDependencies.cpp
+++ b/lib/AST/ModuleDependencies.cpp
@@ -23,21 +23,16 @@
 #include "swift/AST/SourceFile.h"
 #include "swift/Frontend/Frontend.h"
 #include "swift/Strings.h"
-#include "clang/CAS/IncludeTree.h"
-#include "llvm/CAS/CASProvidingFileSystem.h"
-#include "llvm/CAS/CachingOnDiskFileSystem.h"
+#include "clang/Lex/HeaderSearchOptions.h"
 #include "llvm/Config/config.h"
-#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
-#include "llvm/Support/PrefixMapper.h"
-#include <system_error>
 using namespace swift;
 
 ModuleDependencyInfoStorageBase::~ModuleDependencyInfoStorageBase() {}
 
 bool ModuleDependencyInfo::isSwiftModule() const {
   return isSwiftInterfaceModule() || isSwiftSourceModule() ||
-         isSwiftBinaryModule() || isSwiftPlaceholderModule();
+         isSwiftBinaryModule();
 }
 
 bool ModuleDependencyInfo::isTextualSwiftModule() const {
@@ -67,10 +62,6 @@ bool ModuleDependencyInfo::isSwiftBinaryModule() const {
   return isa<SwiftBinaryModuleDependencyStorage>(storage.get());
 }
 
-bool ModuleDependencyInfo::isSwiftPlaceholderModule() const {
-  return isa<SwiftPlaceholderModuleDependencyStorage>(storage.get());
-}
-
 bool ModuleDependencyInfo::isClangModule() const {
   return isa<ClangModuleDependencyStorage>(storage.get());
 }
@@ -98,10 +89,28 @@ ModuleDependencyInfo::getAsClangModule() const {
   return dyn_cast<ClangModuleDependencyStorage>(storage.get());
 }
 
-/// Retrieve the dependencies for a placeholder dependency module stub.
-const SwiftPlaceholderModuleDependencyStorage *
-ModuleDependencyInfo::getAsPlaceholderDependencyModule() const {
-  return dyn_cast<SwiftPlaceholderModuleDependencyStorage>(storage.get());
+std::string ModuleDependencyInfo::getModuleDefiningPath() const {
+  std::string path = "";
+  switch (getKind()) {
+  case swift::ModuleDependencyKind::SwiftInterface:
+    path = getAsSwiftInterfaceModule()->swiftInterfaceFile;
+    break;
+  case swift::ModuleDependencyKind::SwiftBinary:
+    path = getAsSwiftBinaryModule()->compiledModulePath;
+    break;
+  case swift::ModuleDependencyKind::Clang:
+    path = getAsClangModule()->moduleMapFile;
+    break;
+  case swift::ModuleDependencyKind::SwiftSource:
+    path = getAsSwiftSourceModule()->sourceFiles.front();
+    break;
+  default:
+    llvm_unreachable("Unexpected dependency kind");
+  }
+
+  // Relative to the `module.modulemap` or `.swiftinterface` or `.swiftmodule`,
+  // the defininig path is the parent directory of the file.
+  return llvm::sys::path::parent_path(path).str();
 }
 
 void ModuleDependencyInfo::addTestableImport(ImportPath::Module module) {
@@ -117,14 +126,34 @@ bool ModuleDependencyInfo::isTestableImport(StringRef moduleName) const {
 }
 
 void ModuleDependencyInfo::addOptionalModuleImport(
-    StringRef module, bool isExported, llvm::StringSet<> *alreadyAddedModules) {
-  if (!alreadyAddedModules || alreadyAddedModules->insert(module).second)
-    storage->optionalModuleImports.push_back({module.str(), isExported});
+    StringRef module, bool isExported, AccessLevel accessLevel,
+    llvm::StringSet<> *alreadyAddedModules) {
+
+  if (alreadyAddedModules && alreadyAddedModules->contains(module)) {
+    // Find a prior import of this module and add import location
+    // and adjust whether or not this module is ever imported as exported
+    // as well as the access level
+    for (auto &existingImport : storage->optionalModuleImports) {
+      if (existingImport.importIdentifier == module) {
+        existingImport.isExported |= isExported;
+        existingImport.accessLevel = std::max(existingImport.accessLevel,
+                                              accessLevel);
+        break;
+      }
+    }
+  } else {
+    if (alreadyAddedModules)
+      alreadyAddedModules->insert(module);
+
+    storage->optionalModuleImports.push_back(
+         {module.str(), isExported, accessLevel});
+  }
 }
 
 void ModuleDependencyInfo::addModuleImport(
-    StringRef module, bool isExported, llvm::StringSet<> *alreadyAddedModules,
-    const SourceManager *sourceManager, SourceLoc sourceLocation) {
+    StringRef module, bool isExported, AccessLevel accessLevel,
+    llvm::StringSet<> *alreadyAddedModules, const SourceManager *sourceManager,
+    SourceLoc sourceLocation) {
   auto scannerImportLocToDiagnosticLocInfo =
       [&sourceManager](SourceLoc sourceLocation) {
         auto lineAndColumnNumbers =
@@ -139,13 +168,16 @@ void ModuleDependencyInfo::addModuleImport(
   if (alreadyAddedModules && alreadyAddedModules->contains(module)) {
     // Find a prior import of this module and add import location
     // and adjust whether or not this module is ever imported as exported
+    // as well as the access level
     for (auto &existingImport : storage->moduleImports) {
       if (existingImport.importIdentifier == module) {
         if (validSourceLocation) {
           existingImport.addImportLocation(
-            scannerImportLocToDiagnosticLocInfo(sourceLocation));
+              scannerImportLocToDiagnosticLocInfo(sourceLocation));
         }
         existingImport.isExported |= isExported;
+        existingImport.accessLevel = std::max(existingImport.accessLevel,
+                                              accessLevel);
         break;
       }
     }
@@ -155,16 +187,18 @@ void ModuleDependencyInfo::addModuleImport(
 
     if (validSourceLocation)
       storage->moduleImports.push_back(ScannerImportStatementInfo(
-          module.str(), isExported, scannerImportLocToDiagnosticLocInfo(sourceLocation)));
+          module.str(), isExported, accessLevel,
+          scannerImportLocToDiagnosticLocInfo(sourceLocation)));
     else
       storage->moduleImports.push_back(
-         ScannerImportStatementInfo(module.str(), isExported));
+          ScannerImportStatementInfo(module.str(), isExported, accessLevel));
   }
 }
 
 void ModuleDependencyInfo::addModuleImport(
-    ImportPath::Module module, bool isExported, llvm::StringSet<> *alreadyAddedModules,
-    const SourceManager *sourceManager, SourceLoc sourceLocation) {
+    ImportPath::Module module, bool isExported, AccessLevel accessLevel,
+    llvm::StringSet<> *alreadyAddedModules, const SourceManager *sourceManager,
+    SourceLoc sourceLocation) {
   std::string ImportedModuleName = module.front().Item.str().str();
   auto submodulePath = module.getSubmodulePath();
   if (submodulePath.size() > 0 && !submodulePath[0].Item.empty()) {
@@ -173,11 +207,12 @@ void ModuleDependencyInfo::addModuleImport(
     // module named "Foo_Private". ClangImporter has special support for this.
     if (submoduleComponent.Item.str() == "Private")
       addOptionalModuleImport(ImportedModuleName + "_Private",
+                              isExported, accessLevel,
                               alreadyAddedModules);
   }
 
-  addModuleImport(ImportedModuleName, isExported, alreadyAddedModules,
-                  sourceManager, sourceLocation);
+  addModuleImport(ImportedModuleName, isExported, accessLevel,
+                  alreadyAddedModules, sourceManager, sourceLocation);
 }
 
 void ModuleDependencyInfo::addModuleImports(
@@ -206,6 +241,7 @@ void ModuleDependencyInfo::addModuleImports(
         continue;
 
       addModuleImport(realPath, importDecl->isExported(),
+                      importDecl->getAccessLevel(),
                       &alreadyAddedModules, sourceManager,
                       importDecl->getLoc());
 
@@ -362,11 +398,6 @@ std::string ModuleDependencyInfo::getModuleOutputPath() const {
         cast<SwiftBinaryModuleDependencyStorage>(storage.get());
     return swiftBinaryStorage->compiledModulePath;
   }
-  case swift::ModuleDependencyKind::SwiftPlaceholder: {
-    auto swiftPlaceholderStorage =
-        cast<SwiftPlaceholderModuleDependencyStorage>(storage.get());
-    return swiftPlaceholderStorage->compiledModulePath;
-  }
   default:
     llvm_unreachable("Unexpected dependency kind");
   }
@@ -497,7 +528,6 @@ SwiftDependencyScanningService::SwiftDependencyScanningService() {
       // Swift can handle the working directory optimizaiton
       // already so it is safe to turn on all optimizations.
       clang::tooling::dependencies::ScanningOptimizations::All);
-  SharedFilesystemCache.emplace();
 }
 
 bool
@@ -562,7 +592,8 @@ void swift::dependencies::registerCxxInteropLibraries(
                       return mainModuleName == Name;
                     })) {
     // Only link with CxxStdlib on platforms where the overlay is available.
-    if (Target.isOSDarwin() || Target.isOSLinux() || Target.isOSWindows())
+    if (Target.isOSDarwin() || Target.isOSLinux() || Target.isOSWindows() ||
+        Target.isOSFreeBSD())
       RegistrationCallback(LinkLibrary{"swiftCxxStdlib", LibraryKind::Library,
                                        hasStaticCxxStdlib});
   }
@@ -601,100 +632,6 @@ swift::dependencies::registerBackDeployLibraries(
   #include "swift/Frontend/BackDeploymentLibs.def"
 }
 
-SwiftDependencyTracker::SwiftDependencyTracker(
-    llvm::cas::CachingOnDiskFileSystem &FS, llvm::PrefixMapper *Mapper,
-    const CompilerInvocation &CI)
-    : FS(FS.createProxyFS()), Mapper(Mapper) {
-  auto &SearchPathOpts = CI.getSearchPathOptions();
-
-  auto addCommonFile = [&](StringRef path) {
-    auto file = FS.openFileForRead(path);
-    if (!file)
-      return;
-    auto status = (*file)->status();
-    if (!status)
-      return;
-    auto fileRef = (*file)->getObjectRefForContent();
-    if (!fileRef)
-      return;
-
-    std::string realPath = Mapper ? Mapper->mapToString(path) : path.str();
-    CommonFiles.try_emplace(realPath, **fileRef, (size_t)status->getSize());
-  };
-
-  // Add SDKSetting file.
-  SmallString<256> SDKSettingPath;
-  llvm::sys::path::append(SDKSettingPath, SearchPathOpts.getSDKPath(),
-                          "SDKSettings.json");
-  addCommonFile(SDKSettingPath);
-
-  // Add Legacy layout file.
-  const std::vector<std::string> AllSupportedArches = {
-      "arm64", "arm64e", "x86_64", "i386",
-      "armv7", "armv7s", "armv7k", "arm64_32"};
-
-  for (auto RuntimeLibPath : SearchPathOpts.RuntimeLibraryPaths) {
-    std::error_code EC;
-    for (auto &Arch : AllSupportedArches) {
-      SmallString<256> LayoutFile(RuntimeLibPath);
-      llvm::sys::path::append(LayoutFile, "layouts-" + Arch + ".yaml");
-      addCommonFile(LayoutFile);
-    }
-  }
-
-  // Add VFSOverlay file.
-  for (auto &Overlay: SearchPathOpts.VFSOverlayFiles)
-    addCommonFile(Overlay);
-
-  // Add blocklist file.
-  for (auto &File: CI.getFrontendOptions().BlocklistConfigFilePaths)
-    addCommonFile(File);
-}
-
-void SwiftDependencyTracker::startTracking(bool includeCommonDeps) {
-  TrackedFiles.clear();
-  if (includeCommonDeps) {
-    for (auto &entry : CommonFiles)
-      TrackedFiles.emplace(entry.first(), entry.second);
-  }
-}
-
-void SwiftDependencyTracker::trackFile(const Twine &path) {
-  auto file = FS->openFileForRead(path);
-  if (!file)
-    return;
-  auto status = (*file)->status();
-  if (!status)
-    return;
-  auto fileRef = (*file)->getObjectRefForContent();
-  if (!fileRef)
-    return;
-  std::string realPath =
-      Mapper ? Mapper->mapToString(path.str()) : path.str();
-  TrackedFiles.try_emplace(realPath, **fileRef, (size_t)status->getSize());
-}
-
-llvm::Expected<llvm::cas::ObjectProxy>
-SwiftDependencyTracker::createTreeFromDependencies() {
-  llvm::SmallVector<clang::cas::IncludeTree::FileList::FileEntry> Files;
-  for (auto &file : TrackedFiles) {
-    auto includeTreeFile = clang::cas::IncludeTree::File::create(
-        FS->getCAS(), file.first, file.second.FileRef);
-    if (!includeTreeFile)
-      return includeTreeFile.takeError();
-    Files.push_back(
-        {includeTreeFile->getRef(),
-         (clang::cas::IncludeTree::FileList::FileSizeTy)file.second.Size});
-  }
-
-  auto includeTreeList =
-      clang::cas::IncludeTree::FileList::create(FS->getCAS(), Files, {});
-  if (!includeTreeList)
-    return includeTreeList.takeError();
-
-  return *includeTreeList;
-}
-
 bool SwiftDependencyScanningService::setupCachingDependencyScanningService(
     CompilerInstance &Instance) {
   if (!Instance.getInvocation().getCASOptions().EnableCaching)
@@ -706,55 +643,19 @@ bool SwiftDependencyScanningService::setupCachingDependencyScanningService(
       return false;
 
     // CASOption mismatch, return error.
-    Instance.getDiags().diagnose(
-        SourceLoc(), diag::error_cas,
-        "conflicting CAS options used in scanning service");
+    Instance.getDiags().diagnose(SourceLoc(), diag::error_cas_conflict_options);
     return true;
   }
 
   // Setup CAS.
   CASOpts = Instance.getInvocation().getCASOptions().CASOpts;
-  CAS = Instance.getSharedCASInstance();
-  ActionCache = Instance.getSharedCacheInstance();
-
-  auto CachingFS =
-      llvm::cas::createCachingOnDiskFileSystem(Instance.getObjectStore());
-  if (!CachingFS) {
-    Instance.getDiags().diagnose(SourceLoc(), diag::error_cas,
-                                 toString(CachingFS.takeError()));
-    return true;
-  }
-  CacheFS = std::move(*CachingFS);
-
-  // Setup prefix mapping.
-  auto &ScannerPrefixMapper =
-      Instance.getInvocation().getSearchPathOptions().ScannerPrefixMapper;
-  if (!ScannerPrefixMapper.empty()) {
-    Mapper = std::make_unique<llvm::PrefixMapper>();
-    SmallVector<llvm::MappedPrefix, 4> Prefixes;
-    if (auto E = llvm::MappedPrefix::transformJoined(ScannerPrefixMapper,
-                                                     Prefixes)) {
-      Instance.getDiags().diagnose(SourceLoc(), diag::error_prefix_mapping,
-                                   toString(std::move(E)));
-      return true;
-    }
-    Mapper->addRange(Prefixes);
-    Mapper->sort();
-  }
-
-  UseClangIncludeTree =
-      Instance.getInvocation().getClangImporterOptions().UseClangIncludeTree;
-  const clang::tooling::dependencies::ScanningOutputFormat ClangScanningFormat =
-      UseClangIncludeTree
-          ? clang::tooling::dependencies::ScanningOutputFormat::FullIncludeTree
-          : clang::tooling::dependencies::ScanningOutputFormat::FullTree;
 
   ClangScanningService.emplace(
       clang::tooling::dependencies::ScanningMode::DependencyDirectivesScan,
-      ClangScanningFormat,
+      clang::tooling::dependencies::ScanningOutputFormat::FullIncludeTree,
       Instance.getInvocation().getCASOptions().CASOpts,
       Instance.getSharedCASInstance(), Instance.getSharedCacheInstance(),
-      UseClangIncludeTree ? nullptr : CacheFS,
+      /*CachingOnDiskFileSystem=*/nullptr,
       // The current working directory optimization (off by default)
       // should not impact CAS. We set the optization to all to be
       // consistent with the non-CAS case.
@@ -764,14 +665,9 @@ bool SwiftDependencyScanningService::setupCachingDependencyScanningService(
 }
 
 ModuleDependenciesCache::ModuleDependenciesCache(
-    SwiftDependencyScanningService &globalScanningService,
-    const std::string &mainScanModuleName, const std::string &moduleOutputPath,
-    const std::string &sdkModuleOutputPath, const std::string &scannerContextHash)
-    : globalScanningService(globalScanningService),
-      mainScanModuleName(mainScanModuleName),
+    const std::string &mainScanModuleName, const std::string &scannerContextHash)
+    : mainScanModuleName(mainScanModuleName),
       scannerContextHash(scannerContextHash),
-      moduleOutputPath(moduleOutputPath),
-      sdkModuleOutputPath(sdkModuleOutputPath),
       scanInitializationTime(std::chrono::system_clock::now()) {
   for (auto kind = ModuleDependencyKind::FirstKind;
        kind != ModuleDependencyKind::LastKind; ++kind)
@@ -844,8 +740,6 @@ ModuleDependenciesCache::findSwiftDependency(StringRef moduleName) const {
     return found;
   if (auto found = findDependency(moduleName, ModuleDependencyKind::SwiftSource))
     return found;
-  if (auto found = findDependency(moduleName, ModuleDependencyKind::SwiftPlaceholder))
-    return found;
   return std::nullopt;
 }
 
@@ -885,15 +779,64 @@ void ModuleDependenciesCache::recordDependency(
   map.insert({moduleName, dependency});
 }
 
-void ModuleDependenciesCache::recordDependencies(
-    ModuleDependencyVector dependencies) {
+void ModuleDependenciesCache::recordClangDependencies(
+    const clang::tooling::dependencies::ModuleDepsGraph &dependencies,
+    DiagnosticEngine &diags,
+    BridgeClangDependencyCallback bridgeClangModule) {
   for (const auto &dep : dependencies) {
-    if (!hasDependency(dep.first))
-      recordDependency(dep.first.ModuleName, dep.second);
-    if (dep.second.getKind() == ModuleDependencyKind::Clang) {
-      auto clangModuleDetails = dep.second.getAsClangModule();
-      addSeenClangModule(clang::tooling::dependencies::ModuleID{
-          dep.first.ModuleName, clangModuleDetails->contextHash});
+    auto depID =
+        ModuleDependencyID{dep.ID.ModuleName, ModuleDependencyKind::Clang};
+    if (hasDependency(depID)) {
+      auto priorClangModuleDetails =
+          findKnownDependency(depID).getAsClangModule();
+      DEBUG_ASSERT(priorClangModuleDetails);
+      auto priorContextHash = priorClangModuleDetails->contextHash;
+      auto newContextHash = dep.ID.ContextHash;
+      if (priorContextHash != newContextHash) {
+        // This situation means that within the same scanning action, Clang
+        // Dependency Scanner has produced two different variants of the same
+        // module. This is not supposed to happen, but we are currently
+        // hunting down the rare cases where it does, seemingly due to
+        // differences in Clang Scanner direct by-name queries and transitive
+        // header lookup queries.
+        //
+        // Emit a failure diagnostic here that is hopefully more actionable
+        // for the time being.
+        diags.diagnose(SourceLoc(),
+                           diag::dependency_scan_unexpected_variant,
+                           dep.ID.ModuleName);
+        diags.diagnose(
+            SourceLoc(),
+            diag::dependency_scan_unexpected_variant_context_hash_note,
+            priorContextHash, newContextHash);
+        diags.diagnose(
+            SourceLoc(),
+            diag::dependency_scan_unexpected_variant_module_map_note,
+            priorClangModuleDetails->moduleMapFile, dep.ClangModuleMapFile);
+
+        auto newClangModuleDetails = bridgeClangModule(dep).getAsClangModule();
+        auto diagnoseExtraCommandLineFlags =
+            [&diags](const ClangModuleDependencyStorage *checkModuleDetails,
+                   const ClangModuleDependencyStorage *baseModuleDetails,
+                   bool isNewlyDiscovered) -> void {
+          std::unordered_set<std::string> baseCommandLineSet(
+              baseModuleDetails->buildCommandLine.begin(),
+              baseModuleDetails->buildCommandLine.end());
+          for (const auto &checkArg : checkModuleDetails->buildCommandLine)
+            if (baseCommandLineSet.find(checkArg) == baseCommandLineSet.end())
+              diags.diagnose(
+                  SourceLoc(),
+                  diag::dependency_scan_unexpected_variant_extra_arg_note,
+                  isNewlyDiscovered, checkArg);
+        };
+        diagnoseExtraCommandLineFlags(priorClangModuleDetails,
+                                      newClangModuleDetails, true);
+        diagnoseExtraCommandLineFlags(newClangModuleDetails,
+                                      priorClangModuleDetails, false);
+      }
+    } else {
+      recordDependency(dep.ID.ModuleName, bridgeClangModule(dep));
+      addSeenClangModule(dep.ID);
     }
   }
 }
@@ -910,146 +853,159 @@ void ModuleDependenciesCache::removeDependency(ModuleDependencyID moduleID) {
   map.erase(moduleID.ModuleName);
 }
 
-void
-ModuleDependenciesCache::setImportedSwiftDependencies(ModuleDependencyID moduleID,
-                                                      const ArrayRef<ModuleDependencyID> dependencyIDs) {
+void ModuleDependenciesCache::setImportedSwiftDependencies(
+    ModuleDependencyID moduleID,
+    const ArrayRef<ModuleDependencyID> dependencyIDs) {
   auto dependencyInfo = findKnownDependency(moduleID);
   assert(dependencyInfo.getImportedSwiftDependencies().empty());
 #ifndef NDEBUG
   for (const auto &depID : dependencyIDs)
     assert(depID.Kind != ModuleDependencyKind::Clang);
 #endif
-  // Copy the existing info to a mutable one we can then replace it with, after setting its overlay dependencies.
+  // Copy the existing info to a mutable one we can then replace it with, after
+  // setting its overlay dependencies.
   auto updatedDependencyInfo = dependencyInfo;
   updatedDependencyInfo.setImportedSwiftDependencies(dependencyIDs);
   updateDependency(moduleID, updatedDependencyInfo);
 }
-void
-ModuleDependenciesCache::setImportedClangDependencies(ModuleDependencyID moduleID,
-                                                      const ArrayRef<ModuleDependencyID> dependencyIDs) {
+void ModuleDependenciesCache::setImportedClangDependencies(
+    ModuleDependencyID moduleID,
+    const ArrayRef<ModuleDependencyID> dependencyIDs) {
   auto dependencyInfo = findKnownDependency(moduleID);
   assert(dependencyInfo.getImportedClangDependencies().empty());
 #ifndef NDEBUG
   for (const auto &depID : dependencyIDs)
     assert(depID.Kind == ModuleDependencyKind::Clang);
 #endif
-  // Copy the existing info to a mutable one we can then replace it with, after setting its overlay dependencies.
+  // Copy the existing info to a mutable one we can then replace it with, after
+  // setting its overlay dependencies.
   auto updatedDependencyInfo = dependencyInfo;
   updatedDependencyInfo.setImportedClangDependencies(dependencyIDs);
   updateDependency(moduleID, updatedDependencyInfo);
 }
-void
-ModuleDependenciesCache::setHeaderClangDependencies(ModuleDependencyID moduleID,
-                                                    const ArrayRef<ModuleDependencyID> dependencyIDs) {
+void ModuleDependenciesCache::setHeaderClangDependencies(
+    ModuleDependencyID moduleID,
+    const ArrayRef<ModuleDependencyID> dependencyIDs) {
   auto dependencyInfo = findKnownDependency(moduleID);
 #ifndef NDEBUG
   for (const auto &depID : dependencyIDs)
     assert(depID.Kind == ModuleDependencyKind::Clang);
 #endif
-  // Copy the existing info to a mutable one we can then replace it with, after setting its overlay dependencies.
+  // Copy the existing info to a mutable one we can then replace it with, after
+  // setting its overlay dependencies.
   auto updatedDependencyInfo = dependencyInfo;
   updatedDependencyInfo.setHeaderClangDependencies(dependencyIDs);
   updateDependency(moduleID, updatedDependencyInfo);
 }
-void ModuleDependenciesCache::setSwiftOverlayDependencies(ModuleDependencyID moduleID,
-                                                          const ArrayRef<ModuleDependencyID> dependencyIDs) {
+void ModuleDependenciesCache::setSwiftOverlayDependencies(
+    ModuleDependencyID moduleID,
+    const ArrayRef<ModuleDependencyID> dependencyIDs) {
   auto dependencyInfo = findKnownDependency(moduleID);
   assert(dependencyInfo.getSwiftOverlayDependencies().empty());
 #ifndef NDEBUG
   for (const auto &depID : dependencyIDs)
     assert(depID.Kind != ModuleDependencyKind::Clang);
 #endif
-  // Copy the existing info to a mutable one we can then replace it with, after setting its overlay dependencies.
+  // Copy the existing info to a mutable one we can then replace it with, after
+  // setting its overlay dependencies.
   auto updatedDependencyInfo = dependencyInfo;
   updatedDependencyInfo.setSwiftOverlayDependencies(dependencyIDs);
   updateDependency(moduleID, updatedDependencyInfo);
 }
-void
-ModuleDependenciesCache::setCrossImportOverlayDependencies(ModuleDependencyID moduleID,
-                                                           const ArrayRef<ModuleDependencyID> dependencyIDs) {
+void ModuleDependenciesCache::setCrossImportOverlayDependencies(
+    ModuleDependencyID moduleID,
+    const ModuleDependencyIDCollectionView dependencyIDs) {
   auto dependencyInfo = findKnownDependency(moduleID);
   assert(dependencyInfo.getCrossImportOverlayDependencies().empty());
-  // Copy the existing info to a mutable one we can then replace it with, after setting its overlay dependencies.
+  // Copy the existing info to a mutable one we can then replace it with,
+  // after setting its overlay dependencies.
   auto updatedDependencyInfo = dependencyInfo;
   updatedDependencyInfo.setCrossImportOverlayDependencies(dependencyIDs);
   updateDependency(moduleID, updatedDependencyInfo);
 }
 
-ModuleDependencyIDSetVector
-ModuleDependenciesCache::getAllDependencies(const ModuleDependencyID &moduleID) const {
+ModuleDependencyIDCollectionView ModuleDependenciesCache::getAllDependencies(
+    const ModuleDependencyID &moduleID) const {
   const auto &moduleInfo = findKnownDependency(moduleID);
-  ModuleDependencyIDSetVector result;
-  if (moduleInfo.isSwiftModule()) {
-    auto swiftImportedDepsRef = moduleInfo.getImportedSwiftDependencies();
-    auto headerClangDepsRef = moduleInfo.getHeaderClangDependencies();
-    auto overlayDependenciesRef = moduleInfo.getSwiftOverlayDependencies();
-    result.insert(swiftImportedDepsRef.begin(),
-                  swiftImportedDepsRef.end());
-    result.insert(headerClangDepsRef.begin(),
-                  headerClangDepsRef.end());
-    result.insert(overlayDependenciesRef.begin(),
-                  overlayDependenciesRef.end());
-  }
+  return ModuleDependencyIDCollectionView(
+      moduleInfo.getImportedSwiftDependencies(),
+      moduleInfo.getHeaderClangDependencies(),
+      moduleInfo.getSwiftOverlayDependencies(),
+      moduleInfo.getCrossImportOverlayDependencies(),
+      moduleInfo.getImportedClangDependencies());
+}
 
-  if (moduleInfo.isSwiftSourceModule()) {
-    auto crossImportOverlayDepsRef = moduleInfo.getCrossImportOverlayDependencies();
-    result.insert(crossImportOverlayDepsRef.begin(),
-                  crossImportOverlayDepsRef.end());
-  }
+void ModuleDependenciesCache::addVisibleClangModules(
+    ModuleDependencyID moduleID, const std::vector<std::string> &moduleNames) {
+  if (moduleNames.empty())
+    return;
+  auto dependencyInfo = findKnownDependency(moduleID);
+  auto updatedDependencyInfo = dependencyInfo;
+  updatedDependencyInfo.addVisibleClangModules(moduleNames);
+  updateDependency(moduleID, updatedDependencyInfo);
+}
 
-  auto clangImportedDepsRef = moduleInfo.getImportedClangDependencies();
-  result.insert(clangImportedDepsRef.begin(),
-                clangImportedDepsRef.end());
+llvm::StringSet<> &ModuleDependenciesCache::getVisibleClangModules(
+    ModuleDependencyID moduleID) const {
+  ASSERT(moduleID.Kind == ModuleDependencyKind::SwiftSource ||
+         moduleID.Kind == ModuleDependencyKind::SwiftInterface ||
+         moduleID.Kind == ModuleDependencyKind::SwiftBinary);
+  return findKnownDependency(moduleID).getVisibleClangModules();
+}
 
-  return result;
+ModuleDependencyIDCollectionView
+ModuleDependenciesCache::getDirectImportedDependencies(
+    const ModuleDependencyID &moduleID) const {
+  const auto &moduleInfo = findKnownDependency(moduleID);
+  return ModuleDependencyIDCollectionView(
+      moduleInfo.getImportedSwiftDependencies(),
+      moduleInfo.getImportedClangDependencies());
 }
 
-ModuleDependencyIDSetVector
-ModuleDependenciesCache::getClangDependencies(const ModuleDependencyID &moduleID) const {
+ModuleDependencyIDCollectionView
+ModuleDependenciesCache::getAllClangDependencies(
+    const ModuleDependencyID &moduleID) const {
   const auto &moduleInfo = findKnownDependency(moduleID);
-  ModuleDependencyIDSetVector result;
-  auto clangImportedDepsRef = moduleInfo.getImportedClangDependencies();
-  result.insert(clangImportedDepsRef.begin(),
-                clangImportedDepsRef.end());
-  if (moduleInfo.isSwiftSourceModule() || moduleInfo.isSwiftBinaryModule()) {
-    auto headerClangDepsRef = moduleInfo.getHeaderClangDependencies();
-    result.insert(headerClangDepsRef.begin(),
-                  headerClangDepsRef.end());
-  }
-  return result;
+  return ModuleDependencyIDCollectionView(
+      moduleInfo.getImportedClangDependencies(),
+      moduleInfo.getHeaderClangDependencies());
 }
 
 llvm::ArrayRef<ModuleDependencyID>
-ModuleDependenciesCache::getImportedSwiftDependencies(const ModuleDependencyID &moduleID) const {
+ModuleDependenciesCache::getImportedSwiftDependencies(
+    const ModuleDependencyID &moduleID) const {
   const auto &moduleInfo = findKnownDependency(moduleID);
   assert(moduleInfo.isSwiftModule());
   return moduleInfo.getImportedSwiftDependencies();
 }
 
 llvm::ArrayRef<ModuleDependencyID>
-ModuleDependenciesCache::getImportedClangDependencies(const ModuleDependencyID &moduleID) const {
+ModuleDependenciesCache::getImportedClangDependencies(
+    const ModuleDependencyID &moduleID) const {
   const auto &moduleInfo = findKnownDependency(moduleID);
   return moduleInfo.getImportedClangDependencies();
 }
 
 llvm::ArrayRef<ModuleDependencyID>
-ModuleDependenciesCache::getHeaderClangDependencies(const ModuleDependencyID &moduleID) const {
+ModuleDependenciesCache::getHeaderClangDependencies(
+    const ModuleDependencyID &moduleID) const {
   const auto &moduleInfo = findKnownDependency(moduleID);
   assert(moduleInfo.isSwiftModule());
   return moduleInfo.getHeaderClangDependencies();
 }
 
 llvm::ArrayRef<ModuleDependencyID>
-ModuleDependenciesCache::getSwiftOverlayDependencies(const ModuleDependencyID &moduleID) const {
+ModuleDependenciesCache::getSwiftOverlayDependencies(
+    const ModuleDependencyID &moduleID) const {
   const auto &moduleInfo = findKnownDependency(moduleID);
   assert(moduleInfo.isSwiftModule());
   return moduleInfo.getSwiftOverlayDependencies();
 }
 
 llvm::ArrayRef<ModuleDependencyID>
-ModuleDependenciesCache::getCrossImportOverlayDependencies(const ModuleDependencyID &moduleID) const {
+ModuleDependenciesCache::getCrossImportOverlayDependencies(
+    const ModuleDependencyID &moduleID) const {
   const auto &moduleInfo = findKnownDependency(moduleID);
   assert(moduleInfo.isSwiftSourceModule());
   return moduleInfo.getCrossImportOverlayDependencies();
 }
-
diff --git a/lib/AST/ModuleLoader.cpp b/lib/AST/ModuleLoader.cpp
index 6bd49ae3a8b41..06e2b2c2adaf4 100644
--- a/lib/AST/ModuleLoader.cpp
+++ b/lib/AST/ModuleLoader.cpp
@@ -240,9 +240,6 @@ ModuleDependencyInfo::collectCrossImportOverlayNames(
     case swift::ModuleDependencyKind::SwiftSource: {
       return result;
     }
-    case swift::ModuleDependencyKind::SwiftPlaceholder: {
-      return result;
-    }
     case swift::ModuleDependencyKind::LastKind:
       llvm_unreachable("Unhandled dependency kind.");
   }
diff --git a/lib/AST/ModuleNameLookup.cpp b/lib/AST/ModuleNameLookup.cpp
index 288625bb5ab20..53d02d5dafb17 100644
--- a/lib/AST/ModuleNameLookup.cpp
+++ b/lib/AST/ModuleNameLookup.cpp
@@ -17,6 +17,8 @@
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/NameLookupRequests.h"
 #include "swift/Basic/Assertions.h"
+#include "clang/AST/Attr.h"
+#include "clang/AST/ExprCXX.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace swift;
@@ -161,11 +163,18 @@ void ModuleNameLookup<LookupStrategy>::lookupInModule(
       moduleOrFile->getParentModule(), overlays);
   if (!overlays.empty()) {
     // If so, look in each of those overlays.
-    for (auto overlay : overlays)
-      lookupInModule(decls, overlay, accessPath, moduleScopeContext, options);
+    bool selfOverlay = false;
+    for (auto overlay : overlays) {
+      if (overlay == moduleOrFile->getParentModule())
+        selfOverlay = true;
+      else
+        lookupInModule(decls, overlay, accessPath, moduleScopeContext,
+                       options);
+    }
     // FIXME: This may not work gracefully if more than one of these lookups
     // finds something.
-    return;
+    if (!selfOverlay)
+      return;
   }
 
   const size_t initialCount = decls.size();
@@ -278,6 +287,43 @@ void ModuleNameLookup<LookupStrategy>::lookupInModule(
   if (decls.size() - initialCount <= 1)
     return;
 
+  // Some functions like `memchr` are defined both in libc and in libc++.
+  // Importing both would result in ambiguities, but there are some attributes
+  // that mark the preferred overloads. See _LIBCPP_PREFERRED_OVERLOAD.
+  llvm::SmallPtrSet<ValueDecl *, 4> declsToRemove;
+  bool hasPreferredOverload = false;
+  for (auto decl : decls)
+    if (const auto *clangDecl = decl->getClangDecl()) {
+      if (clangDecl->hasAttr<clang::EnableIfAttr>()) {
+        // FIXME: at some point we might want to call into Clang to implement
+        // the full enable_if semantics including the constant evaluation of the
+        // conditions. For now, just look for the first enable_if(true, "...")
+        // and assume all the rest of the enable_ifs evaluate to true.
+        bool thisDeclHasPreferredOverload = false;
+        for (auto clangAttr :
+             clangDecl->specific_attrs<clang::EnableIfAttr>()) {
+          if (auto litExpr =
+                  dyn_cast<clang::CXXBoolLiteralExpr>(clangAttr->getCond())) {
+            if (litExpr->getValue()) {
+              thisDeclHasPreferredOverload = hasPreferredOverload = true;
+              break;
+            }
+          }
+        }
+        if (!thisDeclHasPreferredOverload)
+          declsToRemove.insert(decl);
+      } else
+        declsToRemove.insert(decl);
+    }
+
+  if (hasPreferredOverload) {
+    decls.erase(std::remove_if(decls.begin() + initialCount, decls.end(),
+                               [&](ValueDecl *d) -> bool {
+                                 return declsToRemove.contains(d);
+                               }),
+                decls.end());
+  }
+
   // Remove duplicated declarations, which can happen when the same module is
   // imported with multiple access paths.
   llvm::SmallPtrSet<ValueDecl *, 4> knownDecls;
diff --git a/lib/AST/NameLookup.cpp b/lib/AST/NameLookup.cpp
index b3ede13438d70..99a0310aa1c58 100644
--- a/lib/AST/NameLookup.cpp
+++ b/lib/AST/NameLookup.cpp
@@ -323,23 +323,16 @@ bool swift::removeOverriddenDecls(SmallVectorImpl<ValueDecl*> &decls) {
     }
 
     while (auto overrides = decl->getOverriddenDecl()) {
-      overridden.insert(overrides);
-
-      // Because initializers from Objective-C base classes have greater
-      // visibility than initializers written in Swift classes, we can
-      // have a "break" in the set of declarations we found, where
-      // C.init overrides B.init overrides A.init, but only C.init and
-      // A.init are in the chain. Make sure we still remove A.init from the
-      // set in this case.
-      if (decl->getBaseName().isConstructor()) {
-        /// FIXME: Avoid the possibility of an infinite loop by fixing the root
-        ///        cause instead (incomplete circularity detection).
-        assert(decl != overrides && "Circular class inheritance?");
-        decl = overrides;
-        continue;
+      if (!overridden.insert(overrides).second) {
+        // If we've already seen a decl then there's no need to visit the decls
+        // that it overrides since they should already be in the set. This also
+        // prevents infinite loops in the case that the AST contains an
+        // override chain with a cycle due to circular inheritance.
+        break;
       }
 
-      break;
+      DEBUG_ASSERT(decl != overrides && "Circular class inheritance?");
+      decl = overrides;
     }
   }
 
@@ -1132,6 +1125,9 @@ enum class DirectlyReferencedTypeLookupFlags {
   /// Include members that would normally be excluded because they come from
   /// modules that have not been imported directly.
   IgnoreMissingImports = 1 << 3,
+
+  /// Whenther we should exclude macro expansions.
+  ExcludeMacroExpansions = 1 << 4,
 };
 
 using DirectlyReferencedTypeLookupOptions =
@@ -2317,6 +2313,13 @@ void NominalTypeDecl::recordObjCMethod(AbstractFunctionDecl *method,
   if (!ObjCMethodLookup && !createObjCMethodLookup())
     return;
 
+  // Only record API decls.
+  Decl *abiRoleDecl = method;
+  if (auto accessor = dyn_cast<AccessorDecl>(method))
+    abiRoleDecl = accessor->getStorage();
+  if (!ABIRoleInfo(abiRoleDecl).providesAPI())
+    return;
+
   // Record the method.
   bool isInstanceMethod = method->isObjCInstanceMethod();
   auto &vec = (*ObjCMethodLookup)[{selector, isInstanceMethod}].Methods;
@@ -2371,7 +2374,9 @@ ObjCCategoryNameMap ClassDecl::getObjCCategoryNameMap() {
 /// the given context.
 static bool shouldRequireImportsInContext(const DeclContext *lookupContext) {
   auto &ctx = lookupContext->getASTContext();
-  if (!ctx.LangOpts.hasFeature(Feature::MemberImportVisibility))
+
+  if (!ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                               /*allowMigration=*/true))
     return false;
 
   // Code outside of the main module (which is often synthesized) isn't subject
@@ -2388,6 +2393,8 @@ static bool isAcceptableLookupResult(const DeclContext *dc, NLOptions options,
                                      ValueDecl *decl,
                                      bool onlyCompleteObjectInits,
                                      bool requireImport) {
+  auto &ctx = dc->getASTContext();
+
   // Filter out designated initializers, if requested.
   if (onlyCompleteObjectInits) {
     if (auto ctor = dyn_cast<ConstructorDecl>(decl)) {
@@ -2405,19 +2412,43 @@ static bool isAcceptableLookupResult(const DeclContext *dc, NLOptions options,
   }
 
   // Check access.
-  if (!(options & NL_IgnoreAccessControl) &&
-      !dc->getASTContext().isAccessControlDisabled()) {
+  if (!(options & NL_IgnoreAccessControl) && !ctx.isAccessControlDisabled()) {
     bool allowUsableFromInline = options & NL_IncludeUsableFromInline;
     if (!decl->isAccessibleFrom(dc, /*forConformance*/ false,
                                 allowUsableFromInline))
       return false;
   }
 
-  // Check that there is some import in the originating context that makes this
-  // decl visible.
-  if (requireImport && !(options & NL_IgnoreMissingImports))
-    if (!dc->isDeclImported(decl))
-      return false;
+  if (requireImport) {
+    // Check that there is some import in the originating context that makes
+    // this decl visible.
+    if (!(options & NL_IgnoreMissingImports)) {
+      if (!dc->isDeclImported(decl))
+        return false;
+    }
+
+    // Unlike in Swift, Obj-C allows method overrides to be declared in
+    // extensions (categories), even outside of the module that defines the
+    // type that is being extended. When MemberImportVisibility is enabled,
+    // if these overrides are not filtered out they can hijack name
+    // lookup and cause the compiler to insist that the module that defines
+    // the extension be imported, contrary to developer expectations.
+    //
+    // Filter results belonging to these extensions out, even when ignoring
+    // missing imports, if we're in a context that requires imports to access
+    // member declarations.
+    if (decl->getOverriddenDecl()) {
+      if (auto *extension = dyn_cast<ExtensionDecl>(decl->getDeclContext())) {
+        if (auto *nominal = extension->getExtendedNominal()) {
+          auto extensionMod = extension->getModuleContext();
+          auto nominalMod = nominal->getModuleContext();
+          if (!extensionMod->isSameModuleLookingThroughOverlays(nominalMod) &&
+              !dc->isDeclImported(extension))
+            return false;
+        }
+      }
+    }
+  }
 
   // Check that it has the appropriate ABI role.
   if (!ABIRoleInfo(decl).matchesOptions(options))
@@ -2713,6 +2744,18 @@ QualifiedLookupRequest::evaluate(Evaluator &eval, const DeclContext *DC,
       }
     }
 
+    // Qualified name lookup can find generic value parameters.
+    auto gpList = current->getGenericParams();
+
+    // .. But not in type contexts (yet)
+    if (!(options & NL_OnlyTypes) && gpList && !member.isSpecial()) {
+      auto gp = gpList->lookUpGenericParam(member.getBaseIdentifier());
+
+      if (gp && gp->isValue()) {
+        decls.push_back(gp);
+      }
+    }
+
     // If we're not looking at a protocol and we're not supposed to
     // visit the protocols that this type conforms to, skip the next
     // step.
@@ -3025,6 +3068,10 @@ static DirectlyReferencedTypeDecls directReferencesForUnqualifiedTypeLookup(
           DirectlyReferencedTypeLookupFlags::IgnoreMissingImports))
     options |= UnqualifiedLookupFlags::IgnoreMissingImports;
 
+  if (typeLookupOptions.contains(
+          DirectlyReferencedTypeLookupFlags::ExcludeMacroExpansions))
+    options |= UnqualifiedLookupFlags::ExcludeMacroExpansions;
+
   // Manually exclude macro expansions here since the source location
   // is overridden below.
   if (namelookup::isInMacroArgument(dc->getParentSourceFile(), loc))
@@ -3107,6 +3154,10 @@ static llvm::TinyPtrVector<TypeDecl *> directReferencesForQualifiedTypeLookup(
             DirectlyReferencedTypeLookupFlags::IgnoreMissingImports))
       options |= NL_IgnoreMissingImports;
 
+    if (typeLookupOptions.contains(
+            DirectlyReferencedTypeLookupFlags::ExcludeMacroExpansions))
+      options |= NL_ExcludeMacroExpansions;
+
     // Look through the type declarations we were given, resolving them down
     // to nominal type declarations, module declarations, and
     SmallVector<ModuleDecl *, 2> moduleDecls;
@@ -3183,6 +3234,12 @@ directReferencesForTypeRepr(Evaluator &evaluator, ASTContext &ctx,
                                        isolated->getBase(), dc, options);
   }
 
+  case TypeReprKind::CallerIsolated: {
+    auto callerIsolated = cast<CallerIsolatedTypeRepr>(typeRepr);
+    return directReferencesForTypeRepr(evaluator, ctx,
+                                       callerIsolated->getBase(), dc, options);
+  }
+
   case TypeReprKind::Composition: {
     auto composition = cast<CompositionTypeRepr>(typeRepr);
     for (auto component : composition->getTypes()) {
@@ -3349,7 +3406,7 @@ DirectlyReferencedTypeDecls InheritedDeclsReferencedRequest::evaluate(
     if (auto typeDecl = decl.dyn_cast<const TypeDecl *>())
       dc = typeDecl->getInnermostDeclContext();
     else
-      dc = (DeclContext *)decl.get<const ExtensionDecl *>();
+      dc = (DeclContext *)cast<const ExtensionDecl *>(decl);
 
     // If looking at a protocol's inheritance list,
     // do not look at protocol members to avoid circularity.
@@ -3526,31 +3583,38 @@ ProtocolRequirementsRequest::evaluate(Evaluator &evaluator,
   return PD->getASTContext().AllocateCopy(requirements);
 }
 
-NominalTypeDecl *
-ExtendedNominalRequest::evaluate(Evaluator &evaluator,
-                                 ExtensionDecl *ext) const {
-  auto typeRepr = ext->getExtendedTypeRepr();
+NominalTypeDecl *ExtensionDecl::computeExtendedNominal(
+    bool excludeMacroExpansions) const {
+  auto typeRepr = getExtendedTypeRepr();
   if (!typeRepr) {
     // We must've seen 'extension { ... }' during parsing.
     return nullptr;
   }
 
-  ASTContext &ctx = ext->getASTContext();
+  ASTContext &ctx = getASTContext();
+  auto &evaluator = ctx.evaluator;
   auto options = defaultDirectlyReferencedTypeLookupOptions;
-  if (ext->isInSpecializeExtensionContext()) {
+
+  if (isInSpecializeExtensionContext()) {
     options |= DirectlyReferencedTypeLookupFlags::AllowUsableFromInline;
   }
+
+  if (excludeMacroExpansions) {
+    options |= DirectlyReferencedTypeLookupFlags::ExcludeMacroExpansions;
+  }
+
   DirectlyReferencedTypeDecls referenced = directReferencesForTypeRepr(
-      evaluator, ctx, typeRepr, ext->getParent(), options);
+      evaluator, ctx, typeRepr, getParent(), options);
 
   // If there were no results, expand the lookup to include members that are
   // inaccessible due to missing imports. The missing imports will be diagnosed
   // elsewhere.
   if (referenced.first.empty() &&
-      ctx.LangOpts.hasFeature(Feature::MemberImportVisibility)) {
+      ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                              /*allowMigration=*/true)) {
     options |= DirectlyReferencedTypeLookupFlags::IgnoreMissingImports;
     referenced = directReferencesForTypeRepr(evaluator, ctx, typeRepr,
-                                             ext->getParent(), options);
+                                             getParent(), options);
   }
 
   // Resolve those type declarations to nominal type declarations.
@@ -3566,7 +3630,24 @@ ExtendedNominalRequest::evaluate(Evaluator &evaluator,
   if (nominalTypes.empty())
     return nullptr;
 
-  return nominalTypes[0];
+  auto *result = nominalTypes[0];
+
+  // Tuple extensions are experimental, if the feature isn't enabled let's not
+  // bind this extension at all. This fixes a bunch of crashers that we don't
+  // yet properly handle with the feature enabled.
+  if (isa<BuiltinTupleDecl>(result) &&
+      !ctx.LangOpts.hasFeature(Feature::TupleConformances)) {
+    return nullptr;
+  }
+
+  return result;
+}
+
+NominalTypeDecl *
+ExtendedNominalRequest::evaluate(Evaluator &evaluator,
+                                 const ExtensionDecl *ext) const {
+  ASSERT(ext->canNeverBeBound() && "Should have been bound by bindExtensions");
+  return ext->computeExtendedNominal();
 }
 
 /// Whether there are only associated types in the set of declarations.
@@ -3953,9 +4034,8 @@ CustomAttrNominalRequest::evaluate(Evaluator &evaluator,
                 .diagnose(loc, diag::warn_property_wrapper_module_scope, name,
                           moduleName)
                 .fixItInsert(loc, moduleName.str().str() + ".");
-            ctx.Diags.diagnose(assocType, diag::kind_declname_declared_here,
-                               assocType->getDescriptiveKind(),
-                               assocType->getName());
+            ctx.Diags.diagnose(assocType, diag::decl_declared_here_with_kind,
+                               assocType);
 
             auto *baseTR = UnqualifiedIdentTypeRepr::create(
                 ctx, nameLoc, DeclNameRef(moduleName));
@@ -4026,7 +4106,8 @@ void swift::getDirectlyInheritedNominalTypeDecls(
 
   // Form the result.
   for (auto nominal : nominalTypes) {
-    result.push_back({nominal, loc, attributes, isSuppressed});
+    result.push_back({nominal, loc, inheritedTypes.getTypeRepr(i), attributes,
+                      isSuppressed});
   }
 }
 
@@ -4059,8 +4140,8 @@ swift::getDirectlyInheritedNominalTypeDecls(
     ConformanceAttributes attributes;
     if (attr->isUnchecked())
       attributes.uncheckedLoc = loc;
-    result.push_back(
-        {attr->getProtocol(), loc, attributes, /*isSuppressed=*/false});
+    result.push_back({attr->getProtocol(), loc, /*inheritedTypeRepr=*/nullptr,
+                      attributes, /*isSuppressed=*/false});
   }
 
   // Else we have access to this information on the where clause.
@@ -4071,7 +4152,8 @@ swift::getDirectlyInheritedNominalTypeDecls(
   // FIXME: Refactor SelfBoundsFromWhereClauseRequest to dig out
   // the source location.
   for (auto inheritedNominal : selfBounds.decls)
-    result.emplace_back(inheritedNominal, SourceLoc(), ConformanceAttributes(),
+    result.emplace_back(inheritedNominal, SourceLoc(),
+                        /*inheritedTypeRepr=*/nullptr, ConformanceAttributes(),
                         /*isSuppressed=*/false);
 
   return result;
diff --git a/lib/AST/NameLookupRequests.cpp b/lib/AST/NameLookupRequests.cpp
index 08c7ab1aee238..fe6f70340d7c0 100644
--- a/lib/AST/NameLookupRequests.cpp
+++ b/lib/AST/NameLookupRequests.cpp
@@ -58,8 +58,7 @@ void SuperclassDeclRequest::diagnoseCycle(DiagnosticEngine &diags) const {
 
 void SuperclassDeclRequest::noteCycleStep(DiagnosticEngine &diags) const {
   auto decl = std::get<0>(getStorage());
-  diags.diagnose(decl, diag::kind_declname_declared_here,
-                 decl->getDescriptiveKind(), decl->getName());
+  diags.diagnose(decl, diag::through_decl_declared_here_with_kind, decl);
 }
 
 std::optional<ClassDecl *> SuperclassDeclRequest::getCachedResult() const {
@@ -206,22 +205,15 @@ HasMissingDesignatedInitializersRequest::evaluate(Evaluator &evaluator,
 
 std::optional<NominalTypeDecl *>
 ExtendedNominalRequest::getCachedResult() const {
-  // Note: if we fail to compute any nominal declaration, it's considered
-  // a cache miss. This allows us to recompute the extended nominal types
-  // during extension binding.
-  // This recomputation is also what allows you to extend types defined inside
-  // other extensions, regardless of source file order. See \c bindExtensions(),
-  // which uses a worklist algorithm that attempts to bind everything until
-  // fixed point.
   auto ext = std::get<0>(getStorage());
-  if (!ext->hasBeenBound() || !ext->getExtendedNominal())
+  if (!ext->hasBeenBound())
     return std::nullopt;
-  return ext->getExtendedNominal();
+  return ext->ExtendedNominal.getPointer();
 }
 
 void ExtendedNominalRequest::cacheResult(NominalTypeDecl *value) const {
   auto ext = std::get<0>(getStorage());
-  ext->setExtendedNominal(value);
+  const_cast<ExtensionDecl *>(ext)->setExtendedNominal(value);
 }
 
 void ExtendedNominalRequest::writeDependencySink(
diff --git a/lib/AST/PackConformance.cpp b/lib/AST/PackConformance.cpp
index a68c20baa5378..e2f6250b1e71d 100644
--- a/lib/AST/PackConformance.cpp
+++ b/lib/AST/PackConformance.cpp
@@ -48,7 +48,7 @@ PackConformance::PackConformance(PackType *conformingType,
 
   assert(ConformingType->getNumElements() == conformances.size());
   std::uninitialized_copy(conformances.begin(), conformances.end(),
-                          getTrailingObjects<ProtocolConformanceRef>());
+                          getTrailingObjects());
 }
 
 size_t PackConformance::numTrailingObjects(
@@ -63,8 +63,7 @@ bool PackConformance::isInvalid() const {
 
 ArrayRef<ProtocolConformanceRef>
 PackConformance::getPatternConformances() const {
-  return {getTrailingObjects<ProtocolConformanceRef>(),
-          ConformingType->getNumElements()};
+  return getTrailingObjects(ConformingType->getNumElements());
 }
 
 bool PackConformance::isCanonical() const {
@@ -112,8 +111,7 @@ PackType *PackConformance::getTypeWitness(
     // conformance.
     if (auto *packExpansion = packElement->getAs<PackExpansionType>()) {
       auto assocTypePattern =
-        conformances[i].getTypeWitness(packExpansion->getPatternType(),
-                                       assocType, options);
+        conformances[i].getTypeWitness(assocType, options);
 
       packElements.push_back(PackExpansionType::get(
           assocTypePattern, packExpansion->getCountType()));
@@ -121,8 +119,7 @@ PackType *PackConformance::getTypeWitness(
     // If the pack element is a scalar type, replace the scalar type with
     // the associated type witness from the pattern conformance.
     } else {
-      auto assocTypeScalar =
-        conformances[i].getTypeWitness(packElement, assocType, options);
+      auto assocTypeScalar = conformances[i].getTypeWitness(assocType, options);
       packElements.push_back(assocTypeScalar);
     }
   }
@@ -144,24 +141,20 @@ PackConformance *PackConformance::getAssociatedConformance(
     auto packElement = ConformingType->getElementType(i);
 
     if (auto *packExpansion = packElement->getAs<PackExpansionType>()) {
-      auto assocTypePattern =
-        conformances[i].getAssociatedType(packExpansion->getPatternType(),
-                                          assocType);
-      packElements.push_back(PackExpansionType::get(
-          assocTypePattern, packExpansion->getCountType()));
-
       auto assocConformancePattern =
-        conformances[i].getAssociatedConformance(packExpansion->getPatternType(),
-                                                 assocType, protocol);
+        conformances[i].getAssociatedConformance(assocType, protocol);
       packConformances.push_back(assocConformancePattern);
-    } else {
-      auto assocTypeScalar =
-        conformances[i].getAssociatedType(packElement, assocType);
-      packElements.push_back(assocTypeScalar);
 
+      auto assocTypePattern = assocConformancePattern.getType();
+      packElements.push_back(PackExpansionType::get(
+          assocTypePattern, packExpansion->getCountType()));
+    } else {
       auto assocConformanceScalar =
-        conformances[i].getAssociatedConformance(packElement, assocType, protocol);
+        conformances[i].getAssociatedConformance(assocType, protocol);
       packConformances.push_back(assocConformanceScalar);
+
+      auto assocTypeScalar = assocConformanceScalar.getType();
+      packElements.push_back(assocTypeScalar);
     }
   }
 
@@ -202,15 +195,12 @@ PackConformance::subst(InFlightSubstitution &IFS) const {
         // Just substitute the conformance.  We don't directly represent
         // pack expansion conformances here; it's sort of implicit in the
         // corresponding pack element type.
-        substConformances.push_back(
-            origConformances[i].subst(origExpansion->getPatternType(), IFS));
+        substConformances.push_back(origConformances[i].subst(IFS));
       });
     } else {
       // Substitute a scalar element of the original pack.
       substElementTypes.push_back(origElementType.subst(IFS));
-
-      substConformances.push_back(
-          origConformances[i].subst(origElementType, IFS));
+      substConformances.push_back(origConformances[i].subst(IFS));
     }
   }
 
diff --git a/lib/AST/ParameterPack.cpp b/lib/AST/ParameterPack.cpp
index 0384104c5d35d..cf09518406db3 100644
--- a/lib/AST/ParameterPack.cpp
+++ b/lib/AST/ParameterPack.cpp
@@ -307,8 +307,6 @@ static CanPackType getReducedShapeOfPack(const ASTContext &ctx,
     }
 
     // Use () as a placeholder for scalar shape.
-    assert(!elt->template is<PackArchetypeType>() &&
-           "Pack archetype outside of a pack expansion");
     elts.push_back(ctx.TheEmptyTupleType);
   }
 
@@ -382,10 +380,11 @@ unsigned ParameterList::getOrigParamIndex(SubstitutionMap subMap,
     remappedIndex -= substCount;
   }
 
-  llvm::errs() << "Invalid substituted argument index: " << substIndex << "\n";
-  subMap.dump(llvm::errs());
-  dump(llvm::errs());
-  abort();
+  ABORT([&](auto &out) {
+    out << "Invalid substituted argument index: " << substIndex << "\n";
+    subMap.dump(out);
+    dump(out);
+  });
 }
 
 /// <T...> Foo<T, Pack{Int, String}> => Pack{T..., Int, String}
diff --git a/lib/AST/Pattern.cpp b/lib/AST/Pattern.cpp
index d6f6eb4874422..94a2fc40be5c3 100644
--- a/lib/AST/Pattern.cpp
+++ b/lib/AST/Pattern.cpp
@@ -208,22 +208,28 @@ namespace {
       return Action::Continue(P);
     }
 
-    // Only walk into an expression insofar as it doesn't open a new scope -
-    // that is, don't walk into a closure body.
     PreWalkResult<Expr *> walkToExprPre(Expr *E) override {
-      if (isa<ClosureExpr>(E)) {
+      // Only walk into an expression insofar as it doesn't open a new scope -
+      // that is, don't walk into a closure body, TapExpr, or
+      // SingleValueStmtExpr. Also don't walk into key paths since any nested
+      // VarDecls are invalid there, and after being diagnosed by key path
+      // resolution the ASTWalker won't visit them.
+      if (isa<ClosureExpr>(E) || isa<TapExpr>(E) ||
+          isa<SingleValueStmtExpr>(E) || isa<KeyPathExpr>(E)) {
         return Action::SkipNode(E);
       }
       return Action::Continue(E);
     }
 
+    PreWalkAction walkToTypeReprPre(TypeRepr *T) override {
+      // ErrorTypeReprs can contain invalid expressions.
+      return Action::Continue();
+    }
+
     // Don't walk into anything else.
     PreWalkResult<Stmt *> walkToStmtPre(Stmt *S) override {
       return Action::SkipNode(S);
     }
-    PreWalkAction walkToTypeReprPre(TypeRepr *T) override {
-      return Action::SkipNode();
-    }
     PreWalkAction walkToParameterListPre(ParameterList *PL) override {
       return Action::SkipNode();
     }
@@ -460,7 +466,7 @@ TuplePattern *TuplePattern::create(ASTContext &C, SourceLoc lp,
                             alignof(TuplePattern));
   TuplePattern *pattern = ::new (buffer) TuplePattern(lp, n, rp);
   std::uninitialized_copy(elts.begin(), elts.end(),
-                          pattern->getTrailingObjects<TuplePatternElt>());
+                          pattern->getTrailingObjects());
   return pattern;
 }
 
@@ -717,7 +723,7 @@ DeclContext *ContextualPattern::getDeclContext() const {
   if (auto pbd = getPatternBindingDecl())
     return pbd->getDeclContext();
 
-  return declOrContext.get<DeclContext *>();
+  return cast<DeclContext *>(declOrContext);
 }
 
 PatternBindingDecl *ContextualPattern::getPatternBindingDecl() const {
@@ -797,7 +803,7 @@ Pattern::getOwnership(
       case VarDecl::Introducer::Var:
         // If the subpattern type is copyable, then we can bind the variable
         // by copying without requiring more than a borrow of the original.
-        if (!p->hasType() || !p->getType()->isNoncopyable()) {
+        if (!p->hasType() || p->getType()->isCopyable()) {
           break;
         }
         // TODO: An explicit `consuming` binding kind consumes regardless of
diff --git a/lib/AST/PlatformKind.cpp b/lib/AST/PlatformKind.cpp
deleted file mode 100644
index 03b227b3aa411..0000000000000
--- a/lib/AST/PlatformKind.cpp
+++ /dev/null
@@ -1,300 +0,0 @@
-//===--- PlatformKind.cpp - Swift Language Platform Kinds -----------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements the platform kinds for API availability.
-//
-//===----------------------------------------------------------------------===//
-
-#include "swift/AST/PlatformKind.h"
-#include "swift/Basic/Assertions.h"
-#include "swift/Basic/LangOptions.h"
-#include "swift/Basic/Platform.h"
-#include "llvm/ADT/StringSwitch.h"
-#include "llvm/Support/ErrorHandling.h"
-
-
-using namespace swift;
-
-StringRef swift::platformString(PlatformKind platform) {
-  switch (platform) {
-  case PlatformKind::none:
-    return "*";
-#define AVAILABILITY_PLATFORM(X, PrettyName)                                   \
-  case PlatformKind::X:                                                        \
-    return #X;
-#include "swift/AST/PlatformKinds.def"
-  }
-  llvm_unreachable("bad PlatformKind");
-}
-
-StringRef swift::prettyPlatformString(PlatformKind platform) {
-  switch (platform) {
-  case PlatformKind::none:
-    return "*";
-#define AVAILABILITY_PLATFORM(X, PrettyName)                                   \
-  case PlatformKind::X:                                                        \
-    return PrettyName;
-#include "swift/AST/PlatformKinds.def"
-  }
-  llvm_unreachable("bad PlatformKind");
-}
-
-std::optional<PlatformKind> swift::platformFromString(StringRef Name) {
-  if (Name == "*")
-    return PlatformKind::none;
-  return llvm::StringSwitch<std::optional<PlatformKind>>(Name)
-#define AVAILABILITY_PLATFORM(X, PrettyName) .Case(#X, PlatformKind::X)
-#include "swift/AST/PlatformKinds.def"
-      .Case("OSX", PlatformKind::macOS)
-      .Case("OSXApplicationExtension", PlatformKind::macOSApplicationExtension)
-      .Default(std::optional<PlatformKind>());
-}
-
-std::optional<PlatformKind> swift::platformFromUnsigned(unsigned value) {
-  PlatformKind platform = PlatformKind(value);
-  switch (platform) {
-  case PlatformKind::none:
-#define AVAILABILITY_PLATFORM(X, PrettyName) case PlatformKind::X:
-#include "swift/AST/PlatformKinds.def"
-    return platform;
-  }
-  return std::nullopt;
-}
-
-std::optional<StringRef>
-swift::closestCorrectedPlatformString(StringRef candidate) {
-  auto lowerCasedCandidate = candidate.lower();
-  auto lowerCasedCandidateRef = StringRef(lowerCasedCandidate);
-  auto minDistance = std::numeric_limits<unsigned int>::max();
-  std::optional<StringRef> result = std::nullopt;
-#define AVAILABILITY_PLATFORM(X, PrettyName)                                   \
-  {                                                                            \
-    auto platform = StringRef(#X);                                             \
-    auto distance = lowerCasedCandidateRef.edit_distance(platform.lower());    \
-    if (distance == 0) {                                                       \
-      return platform;                                                         \
-    }                                                                          \
-    if (distance < minDistance) {                                              \
-      minDistance = distance;                                                  \
-      result = platform;                                                       \
-    }                                                                          \
-  }
-#include "swift/AST/PlatformKinds.def"
-  // If the most similar platform distance is greater than this threshold,
-  // it's not similar enough to be suggested as correction.
-  const unsigned int distanceThreshold = 5;
-  return (minDistance < distanceThreshold) ? result : std::nullopt;
-}
-
-std::optional<PlatformKind>
-swift::basePlatformForExtensionPlatform(PlatformKind Platform) {
-  switch (Platform) {
-  case PlatformKind::macOSApplicationExtension:
-    return PlatformKind::macOS;
-  case PlatformKind::iOSApplicationExtension:
-    return PlatformKind::iOS;
-  case PlatformKind::macCatalystApplicationExtension:
-    return PlatformKind::macCatalyst;
-  case PlatformKind::tvOSApplicationExtension:
-    return PlatformKind::tvOS;
-  case PlatformKind::watchOSApplicationExtension:
-    return PlatformKind::watchOS;
-  case PlatformKind::visionOSApplicationExtension:
-    return PlatformKind::visionOS;
-  case PlatformKind::macOS:
-  case PlatformKind::iOS:
-  case PlatformKind::macCatalyst:
-  case PlatformKind::tvOS:
-  case PlatformKind::watchOS:
-  case PlatformKind::visionOS:
-  case PlatformKind::OpenBSD:
-  case PlatformKind::Windows:
-  case PlatformKind::none:
-    return std::nullopt;
-  }
-  llvm_unreachable("bad PlatformKind");
-}
-
-static bool isPlatformActiveForTarget(PlatformKind Platform,
-                                      const llvm::Triple &Target,
-                                      bool EnableAppExtensionRestrictions,
-                                      bool ForRuntimeQuery) {
-  if (Platform == PlatformKind::none)
-    return true;
-
-  if (!EnableAppExtensionRestrictions &&
-      isApplicationExtensionPlatform(Platform))
-    return false;
-
-  // FIXME: This is an awful way to get the current OS.
-  switch (Platform) {
-    case PlatformKind::macOS:
-    case PlatformKind::macOSApplicationExtension:
-      return Target.isMacOSX();
-    case PlatformKind::iOS:
-    case PlatformKind::iOSApplicationExtension:
-      if (!ForRuntimeQuery && Target.isXROS()) {
-        return true;
-      }
-      return Target.isiOS() && !Target.isTvOS();
-    case PlatformKind::macCatalyst:
-    case PlatformKind::macCatalystApplicationExtension:
-      return tripleIsMacCatalystEnvironment(Target);
-    case PlatformKind::tvOS:
-    case PlatformKind::tvOSApplicationExtension:
-      return Target.isTvOS();
-    case PlatformKind::watchOS:
-    case PlatformKind::watchOSApplicationExtension:
-      return Target.isWatchOS();
-    case PlatformKind::visionOS:
-    case PlatformKind::visionOSApplicationExtension:
-      return Target.isXROS();
-    case PlatformKind::OpenBSD:
-      return Target.isOSOpenBSD();
-    case PlatformKind::Windows:
-      return Target.isOSWindows();
-    case PlatformKind::none:
-      llvm_unreachable("handled above");
-  }
-  llvm_unreachable("bad PlatformKind");
-}
-
-bool swift::isPlatformActive(PlatformKind Platform, const LangOptions &LangOpts,
-                             bool ForTargetVariant, bool ForRuntimeQuery) {
-  if (ForTargetVariant) {
-    assert(LangOpts.TargetVariant && "Must have target variant triple");
-    return isPlatformActiveForTarget(Platform, *LangOpts.TargetVariant,
-                                     LangOpts.EnableAppExtensionRestrictions,
-                                     ForRuntimeQuery);
-  }
-
-  return isPlatformActiveForTarget(Platform, LangOpts.Target,
-                                   LangOpts.EnableAppExtensionRestrictions, ForRuntimeQuery);
-}
-
-static PlatformKind platformForTriple(const llvm::Triple &triple,
-                                      bool enableAppExtensionRestrictions) {
-  if (triple.isMacOSX()) {
-    return (enableAppExtensionRestrictions
-                ? PlatformKind::macOSApplicationExtension
-                : PlatformKind::macOS);
-  }
-
-  if (triple.isTvOS()) {
-    return (enableAppExtensionRestrictions
-                ? PlatformKind::tvOSApplicationExtension
-                : PlatformKind::tvOS);
-  }
-
-  if (triple.isWatchOS()) {
-    return (enableAppExtensionRestrictions
-                ? PlatformKind::watchOSApplicationExtension
-                : PlatformKind::watchOS);
-  }
-
-  if (triple.isiOS()) {
-    if (tripleIsMacCatalystEnvironment(triple))
-      return (enableAppExtensionRestrictions
-                  ? PlatformKind::macCatalystApplicationExtension
-                  : PlatformKind::macCatalyst);
-    return (enableAppExtensionRestrictions
-                ? PlatformKind::iOSApplicationExtension
-                : PlatformKind::iOS);
-  }
-
-  if (triple.isXROS()) {
-    return (enableAppExtensionRestrictions
-                ? PlatformKind::visionOSApplicationExtension
-                : PlatformKind::visionOS);
-  }
-
-  return PlatformKind::none;
-}
-
-PlatformKind swift::targetPlatform(const LangOptions &LangOpts) {
-  return platformForTriple(LangOpts.Target,
-                           LangOpts.EnableAppExtensionRestrictions);
-}
-
-PlatformKind swift::targetVariantPlatform(const LangOptions &LangOpts) {
-  if (auto variant = LangOpts.TargetVariant)
-    return platformForTriple(*LangOpts.TargetVariant,
-                             LangOpts.EnableAppExtensionRestrictions);
-
-  return PlatformKind::none;
-}
-
-bool swift::inheritsAvailabilityFromPlatform(PlatformKind Child,
-                                             PlatformKind Parent) {
-  if (auto ChildPlatformBase = basePlatformForExtensionPlatform(Child)) {
-    if (Parent == ChildPlatformBase)
-      return true;
-  }
-
-  if (Child == PlatformKind::macCatalyst && Parent == PlatformKind::iOS)
-    return true;
-
-  if (Child == PlatformKind::macCatalystApplicationExtension) {
-    if (Parent == PlatformKind::iOS ||
-        Parent == PlatformKind::iOSApplicationExtension) {
-      return true;
-    }
-  }
-
-  if (Child == PlatformKind::visionOS && Parent == PlatformKind::iOS)
-    return true;
-
-  if (Child == PlatformKind::visionOSApplicationExtension) {
-    if (Parent == PlatformKind::iOS ||
-        Parent == PlatformKind::iOSApplicationExtension) {
-      return true;
-    }
-  }
-
-  return false;
-}
-
-llvm::VersionTuple swift::canonicalizePlatformVersion(
-    PlatformKind platform, const llvm::VersionTuple &version) {
-
-  // Canonicalize macOS version for macOS Big Sur to treat
-  // 10.16 as 11.0.
-  if (platform == PlatformKind::macOS ||
-      platform == PlatformKind::macOSApplicationExtension) {
-    return llvm::Triple::getCanonicalVersionForOS(llvm::Triple::MacOSX,
-                                                  version);
-  }
-
-  return version;
-}
-
-bool swift::isPlatformSPI(PlatformKind Platform) {
-  switch (Platform) {
-  case PlatformKind::macOS:
-  case PlatformKind::macOSApplicationExtension:
-  case PlatformKind::iOS:
-  case PlatformKind::iOSApplicationExtension:
-  case PlatformKind::macCatalyst:
-  case PlatformKind::macCatalystApplicationExtension:
-  case PlatformKind::tvOS:
-  case PlatformKind::tvOSApplicationExtension:
-  case PlatformKind::watchOS:
-  case PlatformKind::watchOSApplicationExtension:
-  case PlatformKind::visionOS:
-  case PlatformKind::visionOSApplicationExtension:
-  case PlatformKind::OpenBSD:
-  case PlatformKind::Windows:
-  case PlatformKind::none:
-    return false;
-  }
-  llvm_unreachable("bad PlatformKind");
-}
diff --git a/lib/AST/PlatformKindUtils.cpp b/lib/AST/PlatformKindUtils.cpp
new file mode 100644
index 0000000000000..e54e6be019bee
--- /dev/null
+++ b/lib/AST/PlatformKindUtils.cpp
@@ -0,0 +1,333 @@
+//===--- AST/PlatformKindUtils.cpp ------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// This file implements operations for working with `PlatformKind`.
+///
+//===----------------------------------------------------------------------===//
+
+#include "swift/AST/PlatformKindUtils.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/Basic/LangOptions.h"
+#include "swift/Basic/Platform.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Support/ErrorHandling.h"
+
+using namespace swift;
+
+StringRef swift::platformString(PlatformKind platform) {
+  switch (platform) {
+  case PlatformKind::none:
+    return "*";
+#define AVAILABILITY_PLATFORM(X, PrettyName)                                   \
+  case PlatformKind::X:                                                        \
+    return #X;
+#include "swift/AST/PlatformKinds.def"
+  }
+  llvm_unreachable("bad PlatformKind");
+}
+
+StringRef swift::prettyPlatformString(PlatformKind platform) {
+  switch (platform) {
+  case PlatformKind::none:
+    return "*";
+#define AVAILABILITY_PLATFORM(X, PrettyName)                                   \
+  case PlatformKind::X:                                                        \
+    return PrettyName;
+#include "swift/AST/PlatformKinds.def"
+  }
+  llvm_unreachable("bad PlatformKind");
+}
+
+std::optional<PlatformKind> swift::platformFromString(StringRef Name) {
+  if (Name == "*")
+    return PlatformKind::none;
+  return llvm::StringSwitch<std::optional<PlatformKind>>(Name)
+#define AVAILABILITY_PLATFORM(X, PrettyName) .Case(#X, PlatformKind::X)
+#include "swift/AST/PlatformKinds.def"
+      .Case("OSX", PlatformKind::macOS)
+      .Case("OSXApplicationExtension", PlatformKind::macOSApplicationExtension)
+      .Default(std::optional<PlatformKind>());
+}
+
+std::optional<PlatformKind> swift::platformFromUnsigned(unsigned value) {
+  PlatformKind platform = PlatformKind(value);
+  switch (platform) {
+  case PlatformKind::none:
+#define AVAILABILITY_PLATFORM(X, PrettyName) case PlatformKind::X:
+#include "swift/AST/PlatformKinds.def"
+    return platform;
+  }
+  return std::nullopt;
+}
+
+std::optional<StringRef>
+swift::closestCorrectedPlatformString(StringRef candidate) {
+  auto lowerCasedCandidate = candidate.lower();
+  auto lowerCasedCandidateRef = StringRef(lowerCasedCandidate);
+  auto minDistance = std::numeric_limits<unsigned int>::max();
+  std::optional<StringRef> result = std::nullopt;
+#define AVAILABILITY_PLATFORM(X, PrettyName)                                   \
+  {                                                                            \
+    auto platform = StringRef(#X);                                             \
+    auto distance = lowerCasedCandidateRef.edit_distance(platform.lower());    \
+    if (distance == 0) {                                                       \
+      return platform;                                                         \
+    }                                                                          \
+    if (distance < minDistance) {                                              \
+      minDistance = distance;                                                  \
+      result = platform;                                                       \
+    }                                                                          \
+  }
+#include "swift/AST/PlatformKinds.def"
+  // If the most similar platform distance is greater than this threshold,
+  // it's not similar enough to be suggested as correction.
+  const unsigned int distanceThreshold = 5;
+  return (minDistance < distanceThreshold) ? result : std::nullopt;
+}
+
+std::optional<PlatformKind>
+swift::basePlatformForExtensionPlatform(PlatformKind Platform) {
+  switch (Platform) {
+  case PlatformKind::macOSApplicationExtension:
+    return PlatformKind::macOS;
+  case PlatformKind::iOSApplicationExtension:
+    return PlatformKind::iOS;
+  case PlatformKind::macCatalystApplicationExtension:
+    return PlatformKind::macCatalyst;
+  case PlatformKind::tvOSApplicationExtension:
+    return PlatformKind::tvOS;
+  case PlatformKind::watchOSApplicationExtension:
+    return PlatformKind::watchOS;
+  case PlatformKind::visionOSApplicationExtension:
+    return PlatformKind::visionOS;
+  case PlatformKind::macOS:
+  case PlatformKind::iOS:
+  case PlatformKind::macCatalyst:
+  case PlatformKind::tvOS:
+  case PlatformKind::watchOS:
+  case PlatformKind::visionOS:
+  case PlatformKind::FreeBSD:
+  case PlatformKind::OpenBSD:
+  case PlatformKind::Windows:
+  case PlatformKind::none:
+    return std::nullopt;
+  }
+  llvm_unreachable("bad PlatformKind");
+}
+
+static bool isPlatformActiveForTarget(PlatformKind Platform,
+                                      const llvm::Triple &Target,
+                                      bool EnableAppExtensionRestrictions,
+                                      bool ForRuntimeQuery) {
+  if (Platform == PlatformKind::none)
+    return true;
+
+  if (!EnableAppExtensionRestrictions &&
+      isApplicationExtensionPlatform(Platform))
+    return false;
+
+  // FIXME: This is an awful way to get the current OS.
+  switch (Platform) {
+    case PlatformKind::macOS:
+    case PlatformKind::macOSApplicationExtension:
+      return Target.isMacOSX();
+    case PlatformKind::iOS:
+    case PlatformKind::iOSApplicationExtension:
+      if (!ForRuntimeQuery && Target.isXROS()) {
+        return true;
+      }
+      return Target.isiOS() && !Target.isTvOS();
+    case PlatformKind::macCatalyst:
+    case PlatformKind::macCatalystApplicationExtension:
+      return tripleIsMacCatalystEnvironment(Target);
+    case PlatformKind::tvOS:
+    case PlatformKind::tvOSApplicationExtension:
+      return Target.isTvOS();
+    case PlatformKind::watchOS:
+    case PlatformKind::watchOSApplicationExtension:
+      return Target.isWatchOS();
+    case PlatformKind::visionOS:
+    case PlatformKind::visionOSApplicationExtension:
+      return Target.isXROS();
+    case PlatformKind::OpenBSD:
+      return Target.isOSOpenBSD();
+    case PlatformKind::FreeBSD:
+      return Target.isOSFreeBSD();
+    case PlatformKind::Windows:
+      return Target.isOSWindows();
+    case PlatformKind::none:
+      llvm_unreachable("handled above");
+  }
+  llvm_unreachable("bad PlatformKind");
+}
+
+bool swift::isPlatformActive(PlatformKind Platform, const LangOptions &LangOpts,
+                             bool ForTargetVariant, bool ForRuntimeQuery) {
+  if (ForTargetVariant) {
+    assert(LangOpts.TargetVariant && "Must have target variant triple");
+    return isPlatformActiveForTarget(Platform, *LangOpts.TargetVariant,
+                                     LangOpts.EnableAppExtensionRestrictions,
+                                     ForRuntimeQuery);
+  }
+
+  return isPlatformActiveForTarget(Platform, LangOpts.Target,
+                                   LangOpts.EnableAppExtensionRestrictions, ForRuntimeQuery);
+}
+
+static PlatformKind platformForTriple(const llvm::Triple &triple,
+                                      bool enableAppExtensionRestrictions) {
+  if (triple.isMacOSX()) {
+    return (enableAppExtensionRestrictions
+                ? PlatformKind::macOSApplicationExtension
+                : PlatformKind::macOS);
+  }
+
+  if (triple.isTvOS()) {
+    return (enableAppExtensionRestrictions
+                ? PlatformKind::tvOSApplicationExtension
+                : PlatformKind::tvOS);
+  }
+
+  if (triple.isWatchOS()) {
+    return (enableAppExtensionRestrictions
+                ? PlatformKind::watchOSApplicationExtension
+                : PlatformKind::watchOS);
+  }
+
+  if (triple.isiOS()) {
+    if (tripleIsMacCatalystEnvironment(triple))
+      return (enableAppExtensionRestrictions
+                  ? PlatformKind::macCatalystApplicationExtension
+                  : PlatformKind::macCatalyst);
+    return (enableAppExtensionRestrictions
+                ? PlatformKind::iOSApplicationExtension
+                : PlatformKind::iOS);
+  }
+
+  if (triple.isXROS()) {
+    return (enableAppExtensionRestrictions
+                ? PlatformKind::visionOSApplicationExtension
+                : PlatformKind::visionOS);
+  }
+
+  return PlatformKind::none;
+}
+
+PlatformKind swift::targetPlatform(const LangOptions &LangOpts) {
+  return platformForTriple(LangOpts.Target,
+                           LangOpts.EnableAppExtensionRestrictions);
+}
+
+PlatformKind swift::targetVariantPlatform(const LangOptions &LangOpts) {
+  if (auto variant = LangOpts.TargetVariant)
+    return platformForTriple(*LangOpts.TargetVariant,
+                             LangOpts.EnableAppExtensionRestrictions);
+
+  return PlatformKind::none;
+}
+
+bool swift::inheritsAvailabilityFromPlatform(PlatformKind Child,
+                                             PlatformKind Parent) {
+  if (auto ChildPlatformBase = basePlatformForExtensionPlatform(Child)) {
+    if (Parent == ChildPlatformBase)
+      return true;
+  }
+
+  if (Child == PlatformKind::macCatalyst && Parent == PlatformKind::iOS)
+    return true;
+
+  if (Child == PlatformKind::macCatalystApplicationExtension) {
+    if (Parent == PlatformKind::iOS ||
+        Parent == PlatformKind::iOSApplicationExtension) {
+      return true;
+    }
+  }
+
+  if (Child == PlatformKind::visionOS && Parent == PlatformKind::iOS)
+    return true;
+
+  if (Child == PlatformKind::visionOSApplicationExtension) {
+    if (Parent == PlatformKind::iOS ||
+        Parent == PlatformKind::iOSApplicationExtension) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+std::optional<llvm::Triple::OSType>
+swift::tripleOSTypeForPlatform(PlatformKind platform) {
+  switch (platform) {
+  case PlatformKind::macOS:
+  case PlatformKind::macOSApplicationExtension:
+    return llvm::Triple::MacOSX;
+  case PlatformKind::iOS:
+  case PlatformKind::iOSApplicationExtension:
+  case PlatformKind::macCatalyst:
+  case PlatformKind::macCatalystApplicationExtension:
+    return llvm::Triple::IOS;
+  case PlatformKind::tvOS:
+  case PlatformKind::tvOSApplicationExtension:
+    return llvm::Triple::TvOS;
+  case PlatformKind::watchOS:
+  case PlatformKind::watchOSApplicationExtension:
+    return llvm::Triple::WatchOS;
+  case PlatformKind::visionOS:
+  case PlatformKind::visionOSApplicationExtension:
+    return llvm::Triple::XROS;
+  case PlatformKind::FreeBSD:
+    return llvm::Triple::FreeBSD;
+  case PlatformKind::OpenBSD:
+    return llvm::Triple::OpenBSD;
+  case PlatformKind::Windows:
+    return llvm::Triple::Win32;
+  case PlatformKind::none:
+    return std::nullopt;
+  }
+  llvm_unreachable("bad PlatformKind");
+}
+
+llvm::VersionTuple
+swift::canonicalizePlatformVersion(PlatformKind platform,
+                                   const llvm::VersionTuple &version) {
+  if (auto osType = tripleOSTypeForPlatform(platform)) {
+    bool isInValidRange = llvm::Triple::isValidVersionForOS(*osType, version);
+    return llvm::Triple::getCanonicalVersionForOS(*osType, version,
+                                                  isInValidRange);
+  }
+
+  return version;
+}
+
+bool swift::isPlatformSPI(PlatformKind Platform) {
+  switch (Platform) {
+  case PlatformKind::macOS:
+  case PlatformKind::macOSApplicationExtension:
+  case PlatformKind::iOS:
+  case PlatformKind::iOSApplicationExtension:
+  case PlatformKind::macCatalyst:
+  case PlatformKind::macCatalystApplicationExtension:
+  case PlatformKind::tvOS:
+  case PlatformKind::tvOSApplicationExtension:
+  case PlatformKind::watchOS:
+  case PlatformKind::watchOSApplicationExtension:
+  case PlatformKind::visionOS:
+  case PlatformKind::visionOSApplicationExtension:
+  case PlatformKind::OpenBSD:
+  case PlatformKind::FreeBSD:
+  case PlatformKind::Windows:
+  case PlatformKind::none:
+    return false;
+  }
+  llvm_unreachable("bad PlatformKind");
+}
diff --git a/lib/AST/PluginLoader.cpp b/lib/AST/PluginLoader.cpp
index 59646d7721192..988543a2ee487 100644
--- a/lib/AST/PluginLoader.cpp
+++ b/lib/AST/PluginLoader.cpp
@@ -13,11 +13,12 @@
 #include "swift/AST/PluginLoader.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/DiagnosticEngine.h"
-#include "swift/AST/DiagnosticsFrontend.h"
+#include "swift/AST/DiagnosticsSema.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/SourceManager.h"
 #include "swift/Parse/Lexer.h"
 #include "llvm/Config/config.h"
+#include "llvm/Support/PrefixMapper.h"
 #include "llvm/Support/VirtualFileSystem.h"
 
 using namespace swift;
@@ -63,9 +64,9 @@ static StringRef pluginModuleNameStringFromPath(StringRef path) {
 
 static llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
 getPluginLoadingFS(ASTContext &Ctx) {
-  // If there is a clang include tree FS, using real file system to load plugin
+  // If there is an immutable file system, using real file system to load plugin
   // as the FS in SourceMgr doesn't support directory iterator.
-  if (Ctx.ClangImporterOpts.HasClangIncludeTreeRoot)
+  if (Ctx.CASOpts.HasImmutableFileSystem)
     return llvm::vfs::getRealFileSystem();
   return Ctx.SourceMgr.getFileSystem();
 }
@@ -96,9 +97,45 @@ PluginLoader::getPluginMap() {
     map[moduleNameIdentifier] = {libPath, execPath};
   };
 
+  std::optional<llvm::PrefixMapper> mapper;
+  if (!PathRemap.empty()) {
+    SmallVector<llvm::MappedPrefix, 4> prefixes;
+    llvm::MappedPrefix::transformPairs(PathRemap, prefixes);
+    mapper.emplace();
+    mapper->addRange(prefixes);
+    mapper->sort();
+  }
+  auto remapPath = [&mapper](StringRef path) {
+    if (!mapper)
+      return path.str();
+    return mapper->mapToString(path);
+  };
+
   auto fs = getPluginLoadingFS(Ctx);
   std::error_code ec;
 
+  auto validateLibrary = [&](StringRef path) -> llvm::Expected<std::string> {
+    auto remappedPath = remapPath(path);
+    if (!Ctx.SearchPathOpts.ResolvedPluginVerification || path.empty())
+      return remappedPath;
+
+    auto currentStat = fs->status(remappedPath);
+    if (!currentStat)
+      return llvm::createFileError(remappedPath, currentStat.getError());
+
+    auto goldStat = Ctx.SourceMgr.getFileSystem()->status(path);
+    if (!goldStat)
+      return llvm::createStringError(
+          "cannot open gold reference library to compare");
+
+    // Compare the size for difference for now.
+    if (currentStat->getSize() != goldStat->getSize())
+      return llvm::createStringError(
+          "plugin has changed since dependency scanning");
+
+    return remappedPath;
+  };
+
   for (auto &entry : Ctx.SearchPathOpts.PluginSearchOpts) {
     switch (entry.getKind()) {
 
@@ -156,9 +193,17 @@ PluginLoader::getPluginMap() {
       // Respect resolved plugin config above other search path, and it can
       // overwrite plugins found by other options or previous resolved
       // configuration.
-      for (auto &moduleName : val.ModuleNames)
-        try_emplace(moduleName, val.LibraryPath, val.ExecutablePath,
+      for (auto &moduleName : val.ModuleNames) {
+        auto libPath = validateLibrary(val.LibraryPath);
+        if (!libPath) {
+          Ctx.Diags.diagnose(SourceLoc(), diag::resolved_macro_changed,
+                             remapPath(val.LibraryPath),
+                             toString(libPath.takeError()));
+          continue;
+        }
+        try_emplace(moduleName, *libPath, remapPath(val.ExecutablePath),
                     /*overwrite*/ true);
+      }
       continue;
     }
     }
diff --git a/lib/AST/PluginRegistry.cpp b/lib/AST/PluginRegistry.cpp
index 6dc98e0349727..c838a505be792 100644
--- a/lib/AST/PluginRegistry.cpp
+++ b/lib/AST/PluginRegistry.cpp
@@ -213,6 +213,7 @@ LoadedExecutablePlugin::PluginProcess::~PluginProcess() {
 #else
   close(input);
   close(output);
+  kill(process.Pid, SIGTERM);
 #endif
 
   // Set `SecondsToWait` non-zero so it waits for the timeout and kill it after
diff --git a/lib/AST/PrettyStackTrace.cpp b/lib/AST/PrettyStackTrace.cpp
index 324a4960a6ce4..9b69556b2af63 100644
--- a/lib/AST/PrettyStackTrace.cpp
+++ b/lib/AST/PrettyStackTrace.cpp
@@ -100,6 +100,12 @@ void swift::printDeclDescription(llvm::raw_ostream &out, const Decl *D,
         case AccessorKind::Read2:
           out << "read2";
           break;
+        case AccessorKind::Borrow:
+          out << "borrow";
+          break;
+        case AccessorKind::Mutate:
+          out << "mutate";
+          break;
         }
 
         out << " for " << ASD->getName();
diff --git a/lib/AST/ProtocolConformance.cpp b/lib/AST/ProtocolConformance.cpp
index 81b0d8596aaaf..f6d072a88478a 100644
--- a/lib/AST/ProtocolConformance.cpp
+++ b/lib/AST/ProtocolConformance.cpp
@@ -28,10 +28,12 @@
 #include "swift/AST/Module.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/PackConformance.h"
+#include "swift/AST/Type.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/Statistic.h"
+#include "swift/ClangImporter/ClangImporter.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/SaveAndRestore.h"
@@ -216,7 +218,6 @@ void NormalProtocolConformance::setSourceKindAndImplyingConformance(
   Bits.NormalProtocolConformance.SourceKind = unsigned(sourceKind);
   if (auto implying = implyingConformance) {
     ImplyingConformance = implying;
-    PreconcurrencyLoc = implying->getPreconcurrencyLoc();
     Bits.NormalProtocolConformance.Options =
         implyingConformance->getOptions().toRaw();
     if (getProtocol()->isMarkerProtocol()) {
@@ -249,6 +250,18 @@ bool ProtocolConformance::isRetroactive() const {
     if (isSameRetroactiveContext(extensionModule, conformingTypeModule)) {
       return false;
     }
+
+    auto *useSF = getDeclContext()->getOutermostParentSourceFile();
+    auto blessesSF = [&](auto &blessed) {
+      auto blessedFileID = SourceFile::FileIDStr::parse(blessed.first);
+      return blessedFileID && blessedFileID->matches(useSF);
+    };
+    auto *clangDecl = dyn_cast_or_null<clang::CXXRecordDecl>(
+        conformingTypeDecl->getClangDecl());
+    if (clangDecl &&
+        llvm::any_of(importer::getPrivateFileIDAttrs(clangDecl), blessesSF)) {
+      return false;
+    }
   }
 
   return true;
@@ -515,6 +528,22 @@ TypeExpr *NormalProtocolConformance::getExplicitGlobalActorIsolation() const {
   return ctx.getGlobalCache().conformanceExplicitGlobalActorIsolation[this];
 }
 
+SourceLoc NormalProtocolConformance::getPreconcurrencyLoc() const {
+  if (!isPreconcurrency()) {
+    return SourceLoc();
+  }
+
+  if (!getInheritedTypeRepr()) {
+    return SourceLoc();
+  }
+
+  return getInheritedTypeRepr()->findAttrLoc(TypeAttrKind::Preconcurrency);
+}
+
+bool NormalProtocolConformance::hasExplicitGlobalActorIsolation() const {
+  return Bits.NormalProtocolConformance.HasExplicitGlobalActor;
+}
+
 void
 NormalProtocolConformance::setExplicitGlobalActorIsolation(TypeExpr *typeExpr) {
   if (!typeExpr) {
@@ -623,14 +652,6 @@ void NormalProtocolConformance::setTypeWitness(AssociatedTypeDecl *assocType,
   TypeWitnesses[assocType] = {type, typeDecl};
 }
 
-Type ProtocolConformance::getAssociatedType(Type assocType) const {
-  assert(assocType->isTypeParameter() &&
-         "associated type must be a type parameter");
-
-  ProtocolConformanceRef ref(const_cast<ProtocolConformance*>(this));
-  return ref.getAssociatedType(getType(), assocType);
-}
-
 ProtocolConformanceRef
 ProtocolConformance::getAssociatedConformance(Type assocType,
                                               ProtocolDecl *protocol) const {
@@ -743,6 +764,13 @@ NormalProtocolConformance::getWitnessUncached(ValueDecl *requirement) const {
   return entry->second;
 }
 
+ProtocolConformanceRef
+SelfProtocolConformance::getAssociatedConformance(Type assocType,
+                                                  ProtocolDecl *protocol) const {
+  ASSERT(assocType->isEqual(protocol->getSelfInterfaceType()));
+  return lookupConformance(getType(), protocol);
+}
+
 Witness SelfProtocolConformance::getWitness(ValueDecl *requirement) const {
   return Witness(requirement, SubstitutionMap(), nullptr, SubstitutionMap(),
                  GenericSignature(), std::nullopt);
@@ -802,6 +830,42 @@ void NormalProtocolConformance::resolveValueWitnesses() const {
                     evaluator::SideEffect());
 }
 
+void NormalProtocolConformance::applyConformanceAttribute(
+    InFlightDiagnostic &diag, std::string attrStr) const {
+  TypeRepr *inheritedTypeRepr = nullptr;
+  {
+    // Look through implied conformances.
+    auto *conformance = this;
+    while (conformance->getSourceKind() == ConformanceEntryKind::Implied) {
+      conformance = conformance->getImplyingConformance();
+    }
+    inheritedTypeRepr = conformance->getInheritedTypeRepr();
+  }
+
+  if (!inheritedTypeRepr) {
+    return;
+  }
+
+  // FIXME: We shouldn't be applying the attribute to all the protocols in a
+  // composition.
+  SourceLoc insertionLoc = [&] {
+    if (auto *attrTypeRepr = dyn_cast<AttributedTypeRepr>(inheritedTypeRepr)) {
+      // If this is a modifier, append, rather than prepend, it to the
+      // attribute list. Because e.g. `@unsafe nonisolated P` does parse,
+      // whereas `nonisolated @unsafe P` does not.
+      if (attrStr[0] != '@') {
+        return attrTypeRepr->getTypeRepr()->getStartLoc();
+      }
+    }
+
+    return inheritedTypeRepr->getStartLoc();
+  }();
+
+  attrStr += " ";
+
+  diag.fixItInsert(insertionLoc, attrStr);
+}
+
 SpecializedProtocolConformance::SpecializedProtocolConformance(
     Type conformingType,
     NormalProtocolConformance *genericConformance,
@@ -896,14 +960,7 @@ SpecializedProtocolConformance::getAssociatedConformance(Type assocType,
   ProtocolConformanceRef conformance =
     GenericConformance->getAssociatedConformance(assocType, protocol);
 
-  auto subMap = getSubstitutionMap();
-
-  Type origType =
-    (conformance.isConcrete()
-       ? conformance.getConcrete()->getType()
-       : GenericConformance->getAssociatedType(assocType));
-
-  return conformance.subst(origType, subMap);
+  return conformance.subst(getSubstitutionMap());
 }
 
 ConcreteDeclRef
@@ -994,9 +1051,12 @@ static bool isVanishingTupleConformance(
 
   auto replacementTypes = substitutions.getReplacementTypes();
   assert(replacementTypes.size() == 1);
-  auto packType = replacementTypes[0]->castTo<PackType>();
 
-  return (packType->getNumElements() == 1 &&
+  // This might not be an actual pack type with an invalid tuple conformance.
+  auto packType = replacementTypes[0]->getAs<PackType>();
+
+  return (packType &&
+          packType->getNumElements() == 1 &&
           !packType->getElementTypes()[0]->is<PackExpansionType>());
 }
 
@@ -1207,7 +1267,7 @@ void NominalTypeDecl::prepareConformanceTable() const {
     }
   }
 
-  // Actor classes conform to the actor protocol.
+  // Actor classes conform to the appropriate actor protocol.
   if (auto classDecl = dyn_cast<ClassDecl>(mutableThis)) {
     if (classDecl->isDistributedActor()) {
       addSynthesized(ctx.getProtocol(KnownProtocolKind::DistributedActor));
diff --git a/lib/AST/ProtocolConformanceRef.cpp b/lib/AST/ProtocolConformanceRef.cpp
index 494511e6573d5..0a1ecfa471b25 100644
--- a/lib/AST/ProtocolConformanceRef.cpp
+++ b/lib/AST/ProtocolConformanceRef.cpp
@@ -67,24 +67,22 @@ ProtocolDecl *ProtocolConformanceRef::getProtocol() const {
 }
 
 ProtocolConformanceRef
-ProtocolConformanceRef::subst(Type origType,
-                              SubstitutionMap subMap,
+ProtocolConformanceRef::subst(SubstitutionMap subMap,
                               SubstOptions options) const {
   InFlightSubstitutionViaSubMap IFS(subMap, options);
-  return subst(origType, IFS);
+  return subst(IFS);
 }
 
 ProtocolConformanceRef
-ProtocolConformanceRef::subst(Type origType,
-                              TypeSubstitutionFn subs,
+ProtocolConformanceRef::subst(TypeSubstitutionFn subs,
                               LookupConformanceFn conformances,
                               SubstOptions options) const {
   InFlightSubstitution IFS(subs, conformances, options);
-  return subst(origType, IFS);
+  return subst(IFS);
 }
 
 ProtocolConformanceRef
-ProtocolConformanceRef::subst(Type origType, InFlightSubstitution &IFS) const {
+ProtocolConformanceRef::subst(InFlightSubstitution &IFS) const {
   if (isInvalid())
     return *this;
 
@@ -93,50 +91,40 @@ ProtocolConformanceRef::subst(Type origType, InFlightSubstitution &IFS) const {
   if (isPack())
     return getPack()->subst(IFS);
 
-  ASSERT(isAbstract());
-  auto *proto = getProtocol();
+  auto *abstract = getAbstract();
+  auto origType = abstract->getType();
+  auto *proto = abstract->getProtocol();
 
   // If the type is an opaque archetype, the conformance will remain abstract,
   // unless we're specifically substituting opaque types.
-  if (origType->getAs<OpaqueTypeArchetypeType>()) {
-    if (!IFS.shouldSubstituteOpaqueArchetypes()) {
-      return forAbstract(origType.subst(IFS), proto);
-    }
+  if (origType->is<OpaqueTypeArchetypeType>() &&
+      !IFS.shouldSubstituteOpaqueArchetypes()) {
+    return forAbstract(origType.subst(IFS), proto);
   }
 
-  // FIXME: Handle local archetypes as above!
-
-  // Otherwise, compute the substituted type.
-  auto substType = origType.subst(IFS);
-
-  // If the type is an existential, it must be self-conforming.
-  // FIXME: This feels like it's in the wrong place.
-  if (substType->isExistentialType()) {
-    auto optConformance =
-        lookupConformance(substType, proto, /*allowMissing=*/true);
-    if (optConformance)
-      return optConformance;
-
-    return ProtocolConformanceRef::forInvalid();
+  // If the type is a local archetype, the conformance will remain abstract,
+  // unless we're specifically substituting local types.
+  if (origType->is<LocalArchetypeType>() &&
+      !IFS.shouldSubstituteLocalArchetypes()) {
+    return forAbstract(origType.subst(IFS), proto);
   }
 
   // Local conformance lookup into the substitution map.
   // FIXME: Pack element level?
-  return IFS.lookupConformance(origType->getCanonicalType(), substType, proto,
-                               /*level=*/0);
+  return IFS.lookupConformance(origType, proto, /*level=*/0);
 }
 
 ProtocolConformanceRef ProtocolConformanceRef::mapConformanceOutOfContext() const {
   if (isConcrete()) {
     return getConcrete()->subst(
         MapTypeOutOfContext(),
-        MakeAbstractConformanceForGenericType(),
+        LookUpConformanceInModule(),
         SubstFlags::PreservePackExpansionLevel |
         SubstFlags::SubstitutePrimaryArchetypes);
   } else if (isPack()) {
     return getPack()->subst(
         MapTypeOutOfContext(),
-        MakeAbstractConformanceForGenericType(),
+        LookUpConformanceInModule(),
         SubstFlags::PreservePackExpansionLevel |
         SubstFlags::SubstitutePrimaryArchetypes);
   } else if (isAbstract()) {
@@ -149,7 +137,7 @@ ProtocolConformanceRef ProtocolConformanceRef::mapConformanceOutOfContext() cons
 }
 
 Type
-ProtocolConformanceRef::getTypeWitnessByName(Type type, Identifier name) const {
+ProtocolConformanceRef::getTypeWitnessByName(Identifier name) const {
   assert(!isInvalid());
 
   // Find the named requirement.
@@ -160,11 +148,11 @@ ProtocolConformanceRef::getTypeWitnessByName(Type type, Identifier name) const {
   if (!assocType)
     return ErrorType::get(proto->getASTContext());
 
-  return getTypeWitness(type, assocType);
+  return getTypeWitness(assocType);
 }
 
 ConcreteDeclRef
-ProtocolConformanceRef::getWitnessByName(Type type, DeclName name) const {
+ProtocolConformanceRef::getWitnessByName(DeclName name) const {
   // Find the named requirement.
   auto *proto = getProtocol();
   auto *requirement = proto->getSingleRequirement(name);
@@ -174,7 +162,7 @@ ProtocolConformanceRef::getWitnessByName(Type type, DeclName name) const {
   // For a type with dependent conformance, just return the requirement from
   // the protocol. There are no protocol conformance tables.
   if (!isConcrete()) {
-    auto subs = SubstitutionMap::getProtocolSubstitutions(proto, type, *this);
+    auto subs = SubstitutionMap::getProtocolSubstitutions(*this);
     return ConcreteDeclRef(requirement, subs);
   }
 
@@ -190,79 +178,61 @@ ProtocolConformanceRef::getConditionalRequirements() const {
     return {};
 }
 
-Type ProtocolConformanceRef::getTypeWitness(Type conformingType,
-                                            AssociatedTypeDecl *assocType,
+Type ProtocolConformanceRef::getTypeWitness(AssociatedTypeDecl *assocType,
                                             SubstOptions options) const {
+  if (isInvalid())
+    return ErrorType::get(assocType->getASTContext());
+
   if (isPack()) {
     auto *pack = getPack();
-    ASSERT(conformingType->isEqual(pack->getType()));
-    return pack->getTypeWitness(assocType);
+    return pack->getTypeWitness(assocType, options);
   }
 
-  auto failed = [&]() {
-    return DependentMemberType::get(ErrorType::get(conformingType),
-                                    assocType);
-  };
-
-  if (isInvalid())
-    return failed();
-
-  auto proto = getProtocol();
-  ASSERT(assocType->getProtocol() == proto);
-
   if (isConcrete()) {
-    auto witnessType = getConcrete()->getTypeWitness(assocType, options);
-    if (!witnessType || witnessType->is<ErrorType>())
-      return failed();
+    auto *concrete = getConcrete();
+    ASSERT(concrete->getProtocol() == assocType->getProtocol());
+
+    auto witnessType = concrete->getTypeWitness(assocType, options);
+    if (!witnessType)
+      return ErrorType::get(assocType->getASTContext());
     return witnessType;
   }
 
-  ASSERT(isAbstract());
+  auto *abstract = getAbstract();
+  auto conformingType = abstract->getType();
+  ASSERT(abstract->getProtocol() == assocType->getProtocol());
 
   if (auto *archetypeType = conformingType->getAs<ArchetypeType>()) {
-    return archetypeType->getNestedType(assocType);
+    auto witnessType = archetypeType->getNestedType(assocType);
+    if (!witnessType)
+      return ErrorType::get(assocType->getASTContext());
+    return witnessType;
   }
 
-  CONDITIONAL_ASSERT(conformingType->isTypeParameter() ||
-                     conformingType->isTypeVariableOrMember() ||
-                     conformingType->is<UnresolvedType>() ||
-                     conformingType->is<PlaceholderType>());
-
   return DependentMemberType::get(conformingType, assocType);
 }
 
-Type ProtocolConformanceRef::getAssociatedType(Type conformingType,
-                                               Type assocType) const {
-  if (isInvalid())
-    return ErrorType::get(assocType->getASTContext());
-
-  auto proto = getProtocol();
-
-  auto substMap =
-    SubstitutionMap::getProtocolSubstitutions(proto, conformingType, *this);
-  return assocType.subst(substMap);
-}
-
 ProtocolConformanceRef
-ProtocolConformanceRef::getAssociatedConformance(Type conformingType,
-                                                 Type assocType,
+ProtocolConformanceRef::getAssociatedConformance(Type assocType,
                                                  ProtocolDecl *protocol) const {
+  if (isInvalid())
+    return *this;
+
   // If this is a pack conformance, project the associated conformances from
   // each pack element.
   if (isPack()) {
     auto *pack = getPack();
-    assert(conformingType->isEqual(pack->getType()));
     return ProtocolConformanceRef(
         pack->getAssociatedConformance(assocType, protocol));
   }
 
   // If this is a concrete conformance, project the associated conformance.
   if (isConcrete()) {
-    auto conformance = getConcrete();
-    assert(conformance->getType()->isEqual(conformingType));
-    return conformance->getAssociatedConformance(assocType, protocol);
+    return getConcrete()->getAssociatedConformance(assocType, protocol);
   }
 
+  auto conformingType = getType();
+
   auto computeSubjectType = [&](Type conformingType) -> Type {
     return assocType.transformRec(
       [&](TypeBase *t) -> std::optional<Type> {
diff --git a/lib/AST/Requirement.cpp b/lib/AST/Requirement.cpp
index 6397486287236..46b38a4340b75 100644
--- a/lib/AST/Requirement.cpp
+++ b/lib/AST/Requirement.cpp
@@ -255,10 +255,11 @@ int Requirement::compare(const Requirement &other) const {
 
   // We should only have multiple conformance requirements.
   if (getKind() != RequirementKind::Conformance) {
-    llvm::errs() << "Unordered generic requirements\n";
-    llvm::errs() << "LHS: "; dump(llvm::errs()); llvm::errs() << "\n";
-    llvm::errs() << "RHS: "; other.dump(llvm::errs()); llvm::errs() << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Unordered generic requirements\n";
+      out << "LHS: "; dump(out); out << "\n";
+      out << "RHS: "; other.dump(out);
+    });
   }
 
   int compareProtos =
diff --git a/lib/AST/RequirementEnvironment.cpp b/lib/AST/RequirementEnvironment.cpp
index d60ea83df6f69..c5648b8a47f72 100644
--- a/lib/AST/RequirementEnvironment.cpp
+++ b/lib/AST/RequirementEnvironment.cpp
@@ -17,8 +17,10 @@
 
 #include "swift/AST/RequirementEnvironment.h"
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/DeclContext.h"
+#include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/GenericSignature.h"
 #include "swift/AST/ProtocolConformance.h"
 #include "swift/AST/TypeCheckRequests.h"
@@ -46,10 +48,8 @@ RequirementEnvironment::RequirementEnvironment(
 
   auto conformanceToWitnessThunkGenericParamFn = [&](GenericTypeParamType *genericParam)
       -> GenericTypeParamType * {
-    return GenericTypeParamType::get(genericParam->getParamKind(),
-                                     genericParam->getDepth() + (covariantSelf ? 1 : 0),
-                                     genericParam->getIndex(),
-                                     genericParam->getValueType(), ctx);
+    return genericParam->withDepth(
+        genericParam->getDepth() + (covariantSelf ? 1 : 0));
   };
 
   // This is a substitution function from the generic parameters of the
@@ -71,7 +71,7 @@ RequirementEnvironment::RequirementEnvironment(
     return t;
   };
   auto conformanceToWitnessThunkConformanceFn =
-      MakeAbstractConformanceForGenericType();
+      LookUpConformanceInModule();
 
   auto substConcreteType = concreteType.subst(
       conformanceToWitnessThunkTypeFn,
@@ -87,18 +87,15 @@ RequirementEnvironment::RequirementEnvironment(
   // parameters of the requirement into a combined context that provides the
   // type parameters of the conformance context and the parameters of the
   // requirement.
-  auto selfType = cast<GenericTypeParamType>(
-      proto->getSelfInterfaceType()->getCanonicalType());
-
   reqToWitnessThunkSigMap = SubstitutionMap::get(reqSig,
-    [selfType, substConcreteType, depth, covariantSelf, &ctx]
+    [substConcreteType, depth, covariantSelf, &ctx]
     (SubstitutableType *type) -> Type {
       // If the conforming type is a class, the protocol 'Self' maps to
       // the class-constrained 'Self'. Otherwise, it maps to the concrete
       // type.
-      if (type->isEqual(selfType)) {
+      if (type->isEqual(ctx.TheSelfType)) {
         if (covariantSelf)
-          return GenericTypeParamType::getType(/*depth=*/0, /*index=*/0, ctx);
+          return ctx.TheSelfType;
         return substConcreteType;
       }
       // Other requirement generic parameters map 1:1 with their depth
@@ -109,50 +106,42 @@ RequirementEnvironment::RequirementEnvironment(
       // invalid code.
       if (genericParam->getDepth() != 1)
         return Type();
-      Type substGenericParam = GenericTypeParamType::get(
-          genericParam->getParamKind(), depth, genericParam->getIndex(),
-          genericParam->getValueType(), ctx);
+      Type substGenericParam = genericParam->withDepth(depth);
       if (genericParam->isParameterPack()) {
         substGenericParam = PackType::getSingletonPackExpansion(
             substGenericParam);
       }
       return substGenericParam;
     },
-    [selfType, substConcreteType, conformance, conformanceDC, covariantSelf, &ctx](
-        CanType type, Type replacement, ProtocolDecl *proto)
+    [substConcreteType, conformance, conformanceDC, covariantSelf, &ctx](
+        InFlightSubstitution &IFS, Type type, ProtocolDecl *proto)
           -> ProtocolConformanceRef {
       // The protocol 'Self' conforms concretely to the conforming type.
-      if (type->isEqual(selfType)) {
-        ASSERT(covariantSelf || replacement->isEqual(substConcreteType));
-
-        if (conformance) {
-          ProtocolConformance *specialized = conformance;
-
-          if (conformance->getGenericSignature()) {
-            auto concreteSubs =
-              substConcreteType->getContextSubstitutionMap(conformanceDC);
-            specialized =
-              ctx.getSpecializedConformance(substConcreteType,
-                                            cast<NormalProtocolConformance>(conformance),
-                                            concreteSubs);
-          }
-
-          // findWitnessedObjCRequirements() does a weird thing by passing in a
-          // DC that is not the conformance DC. Work around it here.
-          if (!specialized->getType()->isEqual(replacement)) {
-            ASSERT(specialized->getType()->isExactSuperclassOf(substConcreteType));
-            ASSERT(covariantSelf ? replacement->is<GenericTypeParamType>()
-                                 : replacement->isEqual(substConcreteType));
-            specialized = ctx.getInheritedConformance(replacement, specialized);
-          }
-
-          return ProtocolConformanceRef(specialized);
+      if (type->isEqual(ctx.TheSelfType) && !covariantSelf && conformance) {
+        ProtocolConformance *specialized = conformance;
+
+        if (conformance->getGenericSignature()) {
+          auto concreteSubs =
+            substConcreteType->getContextSubstitutionMap(conformanceDC);
+          specialized =
+            ctx.getSpecializedConformance(substConcreteType,
+                                          cast<NormalProtocolConformance>(conformance),
+                                          concreteSubs);
+        }
+
+        // findWitnessedObjCRequirements() does a weird thing by passing in a
+        // DC that is not the conformance DC. Work around it here.
+        if (!specialized->getType()->isEqual(substConcreteType)) {
+          ASSERT(specialized->getType()->isExactSuperclassOf(substConcreteType));
+          specialized = ctx.getInheritedConformance(substConcreteType, specialized);
         }
+
+        return ProtocolConformanceRef(specialized);
       }
 
       // All other generic parameters come from the requirement itself
       // and conform abstractly.
-      return MakeAbstractConformanceForGenericType()(type, replacement, proto);
+      return lookupConformance(type.subst(IFS), proto);
     });
 
   // If the requirement itself is non-generic, the witness thunk signature
@@ -162,6 +151,11 @@ RequirementEnvironment::RequirementEnvironment(
       reqSig.getRequirements().size() == 1) {
     witnessThunkSig = conformanceDC->getGenericSignatureOfContext()
         .getCanonicalSignature();
+    if (witnessThunkSig) {
+      reqToWitnessThunkSigMap = reqToWitnessThunkSigMap.subst(
+          witnessThunkSig.getGenericEnvironment()
+              ->getForwardingSubstitutionMap());
+    }
     return;
   }
 
@@ -173,8 +167,7 @@ RequirementEnvironment::RequirementEnvironment(
   // If the conforming type is a class, add a class-constrained 'Self'
   // parameter.
   if (covariantSelf) {
-    auto paramTy = GenericTypeParamType::getType(/*depth=*/0, /*index=*/0, ctx);
-    genericParamTypes.push_back(paramTy);
+    genericParamTypes.push_back(ctx.TheSelfType);
   }
 
   // Now, add all generic parameters from the conforming type.
@@ -188,8 +181,7 @@ RequirementEnvironment::RequirementEnvironment(
   // Next, add requirements.
   SmallVector<Requirement, 2> requirements;
   if (covariantSelf) {
-    auto paramTy = GenericTypeParamType::getType(/*depth=*/0, /*index=*/0, ctx);
-    Requirement reqt(RequirementKind::Superclass, paramTy, substConcreteType);
+    Requirement reqt(RequirementKind::Superclass, ctx.TheSelfType, substConcreteType);
     requirements.push_back(reqt);
   }
 
@@ -210,10 +202,7 @@ RequirementEnvironment::RequirementEnvironment(
     }
 
     // Create an equivalent generic parameter at the next depth.
-    auto substGenericParam = GenericTypeParamType::get(
-        genericParam->getParamKind(), depth, genericParam->getIndex(),
-        genericParam->getValueType(), ctx);
-
+    auto substGenericParam = genericParam->withDepth(depth);
     genericParamTypes.push_back(substGenericParam);
   }
 
@@ -230,4 +219,7 @@ RequirementEnvironment::RequirementEnvironment(
                                           std::move(genericParamTypes),
                                           std::move(requirements),
                                           /*allowInverses=*/false);
+  reqToWitnessThunkSigMap = reqToWitnessThunkSigMap.subst(
+      witnessThunkSig.getGenericEnvironment()
+          ->getForwardingSubstitutionMap());
 }
diff --git a/lib/AST/RequirementMachine/ApplyInverses.cpp b/lib/AST/RequirementMachine/ApplyInverses.cpp
new file mode 100644
index 0000000000000..bed9797a7ec3d
--- /dev/null
+++ b/lib/AST/RequirementMachine/ApplyInverses.cpp
@@ -0,0 +1,268 @@
+//===--- ApplyInverses.cpp - Resolve `~Protocol` anti-constraints ---------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// The `applyInverses` function takes the syntactic representation of a generic
+// signature and applies implicit default constraints on generic parameters for
+// core type capabilities like `Copyable` and `Escapable`. In doing so, it
+// looks for explicit constraint suppression "requirements" like `T: ~Copyable`
+// or same-type constraints that would contradict the implicit requirements and
+// filters out unwanted default requirements.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RequirementLowering.h"
+#include "swift/AST/ASTContext.h"
+#include "swift/AST/ConformanceLookup.h"
+#include "swift/AST/Decl.h"
+#include "swift/AST/DiagnosticsSema.h"
+#include "swift/AST/Requirement.h"
+#include "swift/AST/RequirementSignature.h"
+#include "swift/AST/TypeCheckRequests.h"
+#include "swift/AST/TypeMatcher.h"
+#include "swift/AST/TypeRepr.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/Basic/Defer.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/SetVector.h"
+#include "Diagnostics.h"
+#include "RewriteContext.h"
+#include "NameLookup.h"
+
+using namespace swift;
+using namespace rewriting;
+
+void swift::rewriting::applyInverses(
+    ASTContext &ctx,
+    ArrayRef<Type> gps,
+    ArrayRef<InverseRequirement> inverseList,
+    ArrayRef<StructuralRequirement> explicitRequirements,
+    SmallVectorImpl<StructuralRequirement> &result,
+    SmallVectorImpl<RequirementError> &errors) {
+
+  // Are there even any inverses or same-type requirements to validate?
+  if (inverseList.empty() && explicitRequirements.empty()) {
+    return;
+  }
+
+  const bool allowInverseOnAssocType =
+      ctx.LangOpts.hasFeature(Feature::SuppressedAssociatedTypes);
+      
+  llvm::DenseMap<CanType, CanType> representativeGPs;
+  
+  // Start with an identity mapping.
+  for (auto gp : gps) {
+    auto canGP = gp->getCanonicalType();
+    representativeGPs.insert({canGP, canGP});
+  }
+  bool hadSameTypeConstraintInScope = false;
+
+  // Return the in-scope generic parameter that represents the equivalence class
+  // for `gp`, or return null if the parameter is constrained out of scope.
+  auto representativeGPFor = [&](CanType gp) -> CanType {
+    while (true) {
+      auto found = representativeGPs.find(gp);
+      if (found == representativeGPs.end()) {
+        return CanType();
+      }
+      if (found->second == CanType()) {
+        return CanType();
+      }
+      
+      if (found->second == gp) {
+        return gp;
+      }
+      
+      gp = found->second;
+    }
+  };
+
+  // Look for same-type constraints that equate multiple generic parameters
+  // within the scope so we can treat the equivalence class as a unit.
+  for (auto &explicitReqt : explicitRequirements) {
+    if (explicitReqt.req.getKind() != RequirementKind::SameType) {
+      continue;
+    }
+
+    // If one end of the same-type requirement is in scope, and the other is
+    // a concrete type or out-of-scope generic parameter, then the other
+    // parameter is also effectively out of scope.
+    auto firstTy = explicitReqt.req.getFirstType()->getCanonicalType();
+    auto secondTy = explicitReqt.req.getSecondType()->getCanonicalType();
+    if (!representativeGPs.count(firstTy)
+        && !representativeGPs.count(secondTy)) {
+      // Same type constraint doesn't involve any in-scope generic parameters.
+      continue;
+    }
+
+    CanType typeInScope;
+    CanType typeOutOfScope;
+
+    if (representativeGPs.count(firstTy)
+        && !representativeGPs.count(secondTy)){
+      // First type is constrained out of scope.
+      typeInScope = firstTy;
+      typeOutOfScope = secondTy;
+    } else if (!representativeGPs.count(firstTy)
+               && representativeGPs.count(secondTy)) {
+      // Second type is constrained out of scope.
+      typeInScope = secondTy;
+      typeOutOfScope = firstTy;
+    } else {
+      // Otherwise, both ends of the same-type constraint are in scope.
+      // Fold the lexicographically-greater parameter with the lesser.
+      auto firstGP = cast<GenericTypeParamType>(firstTy);
+      auto secondGP = cast<GenericTypeParamType>(secondTy);
+      
+      if (firstGP == secondGP) {
+        // `T == T` has no effect.
+        continue;
+      }
+      
+      if (firstGP->getDepth() > secondGP->getDepth()
+          || (firstGP->getDepth() == secondGP->getDepth()
+              && firstGP->getIndex() > secondGP->getIndex())) {
+        std::swap(firstGP, secondGP);
+      }
+      
+      hadSameTypeConstraintInScope = true;
+      representativeGPs.insert_or_assign(secondGP, representativeGPFor(firstGP));
+      continue;
+    }
+
+    // If the out-of-scope type is another type parameter or associated type,
+    // then ignore this same-type constraint and allow defaulting to continue.
+    //
+    // It would probably have been more principled to suppress any defaulting
+    // in this case, but this behavior shipped in Swift 6.0 and 6.1, so we
+    // need to maintain source compatibility.
+    if (typeOutOfScope->isTypeParameter()) {
+      continue;
+    }
+    
+    // If the out-of-scope type contains errors, then similarly, ignore the
+    // same type constraint. Any additional diagnostics arising from the type
+    // parameter being left ~Copyable or ~Escapable might be misleading if the
+    // corrected code is attempting to refer to a Copyable or Escapable type.
+    if (typeOutOfScope->hasError()) {
+      continue;
+    }
+    
+    representativeGPs.insert_or_assign(representativeGPFor(typeInScope),
+                                       CanType());
+    hadSameTypeConstraintInScope = true;
+  }
+
+  // Summarize the inverses and diagnose ones that are incorrect.
+  llvm::DenseMap<CanType, InvertibleProtocolSet> inverses;
+  for (auto inverse : inverseList) {
+    auto canSubject = inverse.subject->getCanonicalType();
+
+    // Inverses on associated types are experimental.
+    if (!allowInverseOnAssocType && canSubject->is<DependentMemberType>()) {
+      // Special exception: allow if we're building the stdlib.
+      if (!ctx.MainModule->isStdlibModule()) {
+        errors.push_back(RequirementError::forInvalidInverseSubject(inverse));
+        continue;
+      }
+    }
+
+    // Noncopyable checking support for parameter packs is not implemented yet.
+    if (canSubject->isParameterPack()) {
+      errors.push_back(RequirementError::forInvalidInverseSubject(inverse));
+      continue;
+    }
+
+    // Value generics never have inverse requirements (or the positive thereof).
+    if (canSubject->isValueParameter()) {
+      continue;
+    }
+
+    // If the inverse is on a subject that wasn't permitted by our caller, then
+    // remove and diagnose as an error. This can happen when an inner context
+    // has a constraint on some outer generic parameter, e.g.,
+    //
+    //     protocol P {
+    //       func f() where Self: ~Copyable
+    //     }
+    //
+    if (representativeGPs.find(canSubject) == representativeGPs.end()) {
+      errors.push_back(
+          RequirementError::forInvalidInverseOuterSubject(inverse));
+      continue;
+    }
+
+    auto representativeSubject = representativeGPFor(canSubject);
+    
+    // If the subject is in scope, but same-type constrained to a type out of
+    // scope, then allow inverses to be stated even though they are redundant.
+    // This is because older versions of Swift not only accepted but required
+    // `extension Foo where T == NonCopyableType, T: ~Copyable {}` to be
+    // written, so we need to continue to accept that formulation for source
+    // compatibility.
+    if (!representativeSubject) {
+      continue;
+    }
+
+    auto &state = inverses[representativeSubject];
+
+    // Check if this inverse has already been seen.
+    auto inverseKind = inverse.getKind();
+    if (state.contains(inverseKind))
+      continue;
+
+    state.insert(inverseKind);
+    inverses[representativeSubject] = state;
+  }
+
+  // Fast-path: if there are no valid inverses or same-type constraints, then
+  // there are no requirements to be removed.
+  if (inverses.empty() && !hadSameTypeConstraintInScope) {
+    return;
+  }
+
+  // Scan the structural requirements and cancel out any inferred requirements
+  // based on the inverses we saw.
+  result.erase(llvm::remove_if(result, [&](StructuralRequirement structReq) {
+    auto req = structReq.req;
+
+    if (req.getKind() != RequirementKind::Conformance)
+      return false;
+
+    // Only consider requirements involving an invertible protocol.
+    auto proto = req.getProtocolDecl()->getInvertibleProtocolKind();
+    if (!proto) {
+      return false;
+    }
+
+    // See if this subject is in-scope.
+    auto subject = req.getFirstType()->getCanonicalType();
+    auto representative = representativeGPs.find(subject);
+    if (representative == representativeGPs.end()) {
+      return false;
+    }
+      
+    // If this type is same-type constrained into another equivalence class,
+    // then it doesn't need its own defaulted requirements.
+    if (representative->second != subject) {
+      return true;
+    }
+
+    // We now have found the inferred constraint 'Subject : Proto'.
+    // So, remove it if we have recorded a 'Subject : ~Proto'.
+    auto foundInverses = inverses.find(subject);
+    if (foundInverses == inverses.end()) {
+      return false;
+    }
+    auto recordedInverses = foundInverses->getSecond();
+    return recordedInverses.contains(*proto);
+  }), result.end());
+}
diff --git a/lib/AST/RequirementMachine/ConcreteContraction.cpp b/lib/AST/RequirementMachine/ConcreteContraction.cpp
index 0c3ad8b07b8f7..13c4012e7af38 100644
--- a/lib/AST/RequirementMachine/ConcreteContraction.cpp
+++ b/lib/AST/RequirementMachine/ConcreteContraction.cpp
@@ -302,7 +302,7 @@ ConcreteContraction::substTypeParameterRec(Type type, Position position) const {
         return std::nullopt;
       }
 
-      return conformance.getTypeWitness(*substBaseType, assocType);
+      return conformance.getTypeWitness(assocType);
     }
 
     // An unresolved DependentMemberType stores an identifier. Handle this
diff --git a/lib/AST/RequirementMachine/ConcreteTypeWitness.cpp b/lib/AST/RequirementMachine/ConcreteTypeWitness.cpp
index 7c31a63512294..532dc741f9b23 100644
--- a/lib/AST/RequirementMachine/ConcreteTypeWitness.cpp
+++ b/lib/AST/RequirementMachine/ConcreteTypeWitness.cpp
@@ -249,12 +249,13 @@ void PropertyMap::concretizeTypeWitnessInConformance(
   } else if (conformance.isAbstract()) {
     auto archetype = concreteType->getAs<OpaqueTypeArchetypeType>();
     if (archetype == nullptr) {
-      llvm::errs() << "Should only have an abstract conformance with an "
-                   << "opaque archetype type\n";
-      llvm::errs() << "Symbol: " << concreteConformanceSymbol << "\n";
-      llvm::errs() << "Term: " << key << "\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Should only have an abstract conformance with an opaque "
+            << "archetype type\n";
+        out << "Symbol: " << concreteConformanceSymbol << "\n";
+        out << "Term: " << key << "\n";
+        dump(out);
+      });
     }
 
     typeWitness = archetype->getNestedType(assocType)->getCanonicalType();
diff --git a/lib/AST/RequirementMachine/Diagnostics.cpp b/lib/AST/RequirementMachine/Diagnostics.cpp
index 47f47e21ff137..e57299aefd634 100644
--- a/lib/AST/RequirementMachine/Diagnostics.cpp
+++ b/lib/AST/RequirementMachine/Diagnostics.cpp
@@ -226,6 +226,15 @@ bool swift::rewriting::diagnoseRequirementErrors(
       break;
     }
 
+    case RequirementError::Kind::UnsupportedPackSameType: {
+      if (error.getRequirement().hasError())
+        break;
+
+      ctx.Diags.diagnose(loc, diag::unsupported_pack_same_type);
+      diagnosedError = true;
+      break;
+    }
+
     case RequirementError::Kind::InvalidValueGenericType: {
       auto req = error.getRequirement();
 
@@ -238,14 +247,14 @@ bool swift::rewriting::diagnoseRequirementErrors(
       break;
     }
 
-    case RequirementError::Kind::InvalidValueGenericConformance: {
+    case RequirementError::Kind::InvalidValueGenericConstraint: {
       auto req = error.getRequirement();
 
       if (req.hasError())
         break;
 
-      ctx.Diags.diagnose(loc, diag::invalid_value_generic_conformance,
-                         req.getFirstType(), req.getSecondType());
+      ctx.Diags.diagnose(loc, diag::invalid_value_generic_constraint,
+                         req.getFirstType());
       diagnosedError = true;
       break;
     }
@@ -308,8 +317,9 @@ getRequirementForDiagnostics(Type subject, Symbol property,
                        property.getLayoutConstraint());
 
   default:
-    llvm::errs() << "Bad property symbol: " << property << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Bad property symbol: " << property;
+    });
   }
 }
 
diff --git a/lib/AST/RequirementMachine/Diagnostics.h b/lib/AST/RequirementMachine/Diagnostics.h
index e336842684d4b..d5721a0f631ea 100644
--- a/lib/AST/RequirementMachine/Diagnostics.h
+++ b/lib/AST/RequirementMachine/Diagnostics.h
@@ -53,12 +53,15 @@ struct RequirementError {
     RecursiveRequirement,
     /// A not-yet-supported same-element requirement, e.g. each T == Int.
     UnsupportedSameElement,
+    /// A not-yet-supported same-type requirement involving packs and concrete
+    /// types, e.g. (repeat each T) == (Int, repeat each U).
+    UnsupportedPackSameType,
     /// An unexpected value type used in a value generic,
     /// e.g. 'let N: String'.
     InvalidValueGenericType,
-    /// A value generic type was used to conform to a protocol,
-    /// e.g. 'where N: P' where N == 'let N: Int' and P is some protocol.
-    InvalidValueGenericConformance,
+    /// A generic value parameter was used as the subject of a subtype
+    /// constraint, e.g. `N: X` in `struct S<let N: Int> where N: X`.
+    InvalidValueGenericConstraint,
     /// A value generic type was used to same-type to an unrelated type,
     /// e.g. 'where N == Int' where N == 'let N: Int'.
     InvalidValueGenericSameType,
@@ -162,6 +165,10 @@ struct RequirementError {
     return {Kind::UnsupportedSameElement, req, loc};
   }
 
+  static RequirementError forPackSameType(Requirement req, SourceLoc loc) {
+    return {Kind::UnsupportedPackSameType, req, loc};
+  }
+
   static RequirementError forInvalidValueGenericType(Type subjectType,
                                                      Type constraint,
                                                      SourceLoc loc) {
@@ -169,9 +176,12 @@ struct RequirementError {
     return {Kind::InvalidValueGenericType, requirement, loc};
   }
 
-  static RequirementError forInvalidValueGenericConformance(Requirement req,
-                                                            SourceLoc loc) {
-    return {Kind::InvalidValueGenericConformance, req, loc};
+  static RequirementError forInvalidValueGenericConstraint(Type subjectType,
+                                                           Type constraint,
+                                                           SourceLoc loc) {
+    Requirement requirement(RequirementKind::Conformance, subjectType,
+                            constraint);
+    return {Kind::InvalidValueGenericConstraint, requirement, loc};
   }
 
   static RequirementError forInvalidValueGenericSameType(Type subjectType,
diff --git a/lib/AST/RequirementMachine/GenericSignatureQueries.cpp b/lib/AST/RequirementMachine/GenericSignatureQueries.cpp
index 17423df4efaaa..66d18b5fce70c 100644
--- a/lib/AST/RequirementMachine/GenericSignatureQueries.cpp
+++ b/lib/AST/RequirementMachine/GenericSignatureQueries.cpp
@@ -274,8 +274,9 @@ RequirementMachine::getLongestValidPrefix(const MutableTerm &term) const {
     case Symbol::Kind::ConcreteConformance:
     case Symbol::Kind::Shape:
     case Symbol::Kind::PackElement:
-      llvm::errs() <<"Invalid symbol in a type term: " << term << "\n";
-      abort();
+      ABORT([&](auto &out) {
+        out << "Invalid symbol in a type term: " << term;
+      });
     }
 
     // This symbol is valid, add it to the longest prefix.
@@ -346,12 +347,15 @@ static Type substPrefixType(Type type, unsigned suffixLength, Type prefixType,
   auto *assocDecl = memberType->getAssocType();
   auto *proto = assocDecl->getProtocol();
   auto conformance = lookupConformance(substBaseType, proto);
-  return conformance.getTypeWitness(substBaseType, assocDecl);
+  return conformance.getTypeWitness(assocDecl);
 }
 
 Type RequirementMachine::getReducedTypeParameter(
     CanType t,
     ArrayRef<GenericTypeParamType *> genericParams) const {
+  if (Failed)
+    return ErrorType::get(t);
+
   // Get a simplified term T.
   auto term = Context.getMutableTermForType(t, /*proto=*/nullptr);
   System.simplify(term);
@@ -436,25 +440,25 @@ Type RequirementMachine::getReducedTypeParameter(
   // If U is not concrete, we have an invalid member type of a dependent
   // type, which is not valid in this generic signature. Give up.
   if (prefix.empty() || prefixType->isTypeParameter()) {
-    llvm::errs() << "\n";
-    llvm::errs() << "getReducedTypeParameter() was called\n";
-    llvm::errs() << "       with " << Sig << ",\n";
-    llvm::errs() << "       and " << t << ".\n\n";
-    if (prefix.empty()) {
-      llvm::errs() << "This type parameter contains the generic parameter "
-                   << Type(t->getRootGenericParam()) << ".\n\n";
-      llvm::errs() << "This generic parameter is not part of the given "
-                   << "generic signature.\n\n";
-    } else {
-      llvm::errs() << "This type parameter's reduced term is " << term << ".\n\n";
-      llvm::errs() << "This is not a valid term, because " << prefix << " does not "
-                   << "have a member type named " << term[prefix.size()] << ".\n\n";
-    }
-    llvm::errs() << "This usually indicates the caller passed the wrong type or "
-                 << "generic signature to getReducedType().\n\n";
+    ABORT([&](auto &out) {
+      out << "getReducedTypeParameter() was called\n";
+      out << "       with " << Sig << ",\n";
+      out << "       and " << t << ".\n\n";
+      if (prefix.empty()) {
+        out << "This type parameter contains the generic parameter "
+            << Type(t->getRootGenericParam()) << ".\n\n";
+        out << "This generic parameter is not part of the given "
+            << "generic signature.\n\n";
+      } else {
+        out << "This type parameter's reduced term is " << term << ".\n\n";
+        out << "This is not a valid term, because " << prefix << " does not "
+            << "have a member type named " << term[prefix.size()] << ".\n\n";
+      }
+      out << "This usually indicates the caller passed the wrong type or "
+          << "generic signature to getReducedType().\n\n";
 
-    dump(llvm::errs());
-    abort();
+      dump(out);
+    });
   }
 
   // Compute the type of the unresolved suffix term V.
@@ -603,13 +607,14 @@ RequirementMachine::getConformancePath(Type type,
     }
 
     if (CurrentConformancePaths.empty()) {
-      llvm::errs() << "Failed to find conformance path for ";
-      llvm::errs() << type << " (" << term << ")" << " : ";
-      llvm::errs() << protocol->getName() << ":\n";
-      type.dump(llvm::errs());
-      llvm::errs() << "\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Failed to find conformance path for ";
+        out << type << " (" << term << ")" << " : ";
+        out << protocol->getName() << ":\n";
+        type.dump(out);
+        out << "\n";
+        dump(out);
+      });
     }
 
     // The buffer consists of all conformance paths of length N.
@@ -751,10 +756,11 @@ RequirementMachine::getReducedShapeTerm(Type type) const {
   if (term.size() != 2 ||
       term[0].getKind() != Symbol::Kind::GenericParam ||
       term[1].getKind() != Symbol::Kind::Shape) {
-    llvm::errs() << "Invalid reduced shape\n";
-    llvm::errs() << "Type: " << type << "\n";
-    llvm::errs() << "Term: " << term << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Invalid reduced shape\n";
+      out << "Type: " << type << "\n";
+      out << "Term: " << term;
+    });
   }
 
   MutableTerm reducedTerm(term.begin(), term.end() - 1);
@@ -791,12 +797,16 @@ void RequirementMachine::verify(const MutableTerm &term) const {
                                 return genericParam->isEqual(otherType);
                               });
     if (found == genericParams.end()) {
-      llvm::errs() << "Bad generic parameter in " << term << "\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Bad generic parameter in " << term << "\n";
+        dump(out);
+      });
     }
   }
 
+  if (Failed)
+    return;
+
   MutableTerm erased;
 
   // First, "erase" resolved associated types from the term, and try
@@ -820,8 +830,9 @@ void RequirementMachine::verify(const MutableTerm &term) const {
       case Symbol::Kind::ConcreteType:
       case Symbol::Kind::ConcreteConformance:
       case Symbol::Kind::Shape:
-        llvm::errs() << "Bad initial symbol in " << term << "\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Bad initial symbol in " << term;
+        });
         break;
       }
     }
@@ -847,8 +858,9 @@ void RequirementMachine::verify(const MutableTerm &term) const {
     case Symbol::Kind::ConcreteType:
     case Symbol::Kind::ConcreteConformance:
     case Symbol::Kind::PackElement:
-      llvm::errs() << "Bad interior symbol " << symbol << " in " << term << "\n";
-      abort();
+      ABORT([&](auto &out) {
+        out << "Bad interior symbol " << symbol << " in " << term;
+      });
       break;
     }
   }
@@ -858,12 +870,13 @@ void RequirementMachine::verify(const MutableTerm &term) const {
 
   // We should end up with the same term.
   if (simplified != term) {
-    llvm::errs() << "Term verification failed\n";
-    llvm::errs() << "Initial term:    " << term << "\n";
-    llvm::errs() << "Erased term:     " << erased << "\n";
-    llvm::errs() << "Simplified term: " << simplified << "\n";
-    llvm::errs() << "\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Term verification failed\n";
+      out << "Initial term:    " << term << "\n";
+      out << "Erased term:     " << erased << "\n";
+      out << "Simplified term: " << simplified << "\n";
+      out << "\n";
+      dump(out);
+    });
   }
 }
diff --git a/lib/AST/RequirementMachine/HomotopyReduction.cpp b/lib/AST/RequirementMachine/HomotopyReduction.cpp
index 3efadceb16953..c6ef27428e59f 100644
--- a/lib/AST/RequirementMachine/HomotopyReduction.cpp
+++ b/lib/AST/RequirementMachine/HomotopyReduction.cpp
@@ -291,8 +291,8 @@ RewriteSystem::findRuleToDelete(EliminationPredicate isRedundantRuleFn) {
     {
       // If both are concrete type requirements, prefer to eliminate the
       // one with the more deeply nested type.
-      unsigned ruleNesting = rule.getNesting();
-      unsigned otherRuleNesting = otherRule.getNesting();
+      unsigned ruleNesting = rule.getNestingAndSize().first;
+      unsigned otherRuleNesting = otherRule.getNestingAndSize().first;
 
       if (ruleNesting != otherRuleNesting) {
         if (ruleNesting > otherRuleNesting)
@@ -730,11 +730,11 @@ void RewriteSystem::verifyRedundantConformances(
            "Redundant conformance is not a conformance rule?");
 
     if (!rule.isRedundant()) {
-      llvm::errs() << "Homotopy reduction did not eliminate redundant "
-                   << "conformance?\n";
-      llvm::errs() << "(#" << ruleID << ") " << rule << "\n\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Homotopy reduction did not eliminate redundant conformance?\n";
+        out << "(#" << ruleID << ") " << rule << "\n\n";
+        dump(out);
+      });
     }
   }
 }
@@ -752,10 +752,11 @@ void RewriteSystem::verifyMinimizedRules(
     // Ignore the rewrite rule if it is not part of our minimization domain.
     if (!isInMinimizationDomain(rule.getLHS().getRootProtocol())) {
       if (rule.isRedundant()) {
-        llvm::errs() << "Redundant rule outside minimization domain: "
-                     << rule << "\n\n";
-        dump(llvm::errs());
-        abort();
+        ABORT([&](auto &out) {
+          out << "Redundant rule outside minimization domain: " << rule
+              << "\n\n";
+          dump(out);
+        });
       }
 
       continue;
@@ -765,9 +766,10 @@ void RewriteSystem::verifyMinimizedRules(
     // be redundant.
     if (rule.isPermanent()) {
       if (rule.isRedundant()) {
-        llvm::errs() << "Permanent rule is redundant: " << rule << "\n\n";
-        dump(llvm::errs());
-        abort();
+        ABORT([&](auto &out) {
+          out << "Permanent rule is redundant: " << rule << "\n\n";
+          dump(out);
+        });
       }
 
       continue;
@@ -783,18 +785,20 @@ void RewriteSystem::verifyMinimizedRules(
     if (rule.isLHSSimplified() &&
         !rule.isRedundant() &&
         !rule.isProtocolConformanceRule()) {
-      llvm::errs() << "Simplified rule is not redundant: " << rule << "\n\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Simplified rule is not redundant: " << rule << "\n\n";
+        dump(out);
+      });
     }
 
     // RHS-simplified and substitution-simplified rules should be redundant.
     if ((rule.isRHSSimplified() ||
          rule.isSubstitutionSimplified()) &&
         !rule.isRedundant()) {
-      llvm::errs() << "Simplified rule is not redundant: " << rule << "\n\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Simplified rule is not redundant: " << rule << "\n\n";
+        dump(out);
+      });
     }
 
     if (rule.isRedundant() &&
@@ -803,17 +807,19 @@ void RewriteSystem::verifyMinimizedRules(
         !rule.isSubstitutionSimplified() &&
         !rule.containsNameSymbols() &&
         !redundantConformances.count(ruleID)) {
-      llvm::errs() << "Minimal conformance is redundant: " << rule << "\n\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Minimal conformance is redundant: " << rule << "\n\n";
+        dump(out);
+      });
     }
   }
 
   if (RedundantRules.size() != redundantRuleCount) {
-    llvm::errs() << "Expected " << RedundantRules.size() << " redundant rules "
-                 << "but counted " << redundantRuleCount << "\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Expected " << RedundantRules.size() << " redundant rules "
+          << "but counted " << redundantRuleCount << "\n";
+      dump(out);
+    });
   }
 
   // Replacement paths for redundant rules can only reference other redundant
@@ -823,10 +829,11 @@ void RewriteSystem::verifyMinimizedRules(
   for (const auto &pair : llvm::reverse(RedundantRules)) {
     const auto &rule = getRule(pair.first);
     if (!rule.isRedundant()) {
-      llvm::errs() << "Recorded replacement path for non-redundant rule "
-                   << rule << "\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Recorded replacement path for non-redundant rule " << rule
+            << "\n";
+        dump(out);
+      });
     }
 
     for (const auto &step : pair.second) {
@@ -835,10 +842,11 @@ void RewriteSystem::verifyMinimizedRules(
         const auto &otherRule = getRule(otherRuleID);
         if (otherRule.isRedundant() &&
             !laterRedundantRules.count(otherRuleID)) {
-          llvm::errs() << "Redundant requirement path contains a redundant "
-                          "rule " << otherRule << "\n";
-          dump(llvm::errs());
-          abort();
+          ABORT([&](auto &out) {
+            out << "Redundant requirement path contains a redundant rule "
+                << otherRule << "\n";
+            dump(out);
+          });
         }
       }
     }
diff --git a/lib/AST/RequirementMachine/InterfaceType.cpp b/lib/AST/RequirementMachine/InterfaceType.cpp
index 874edccdba7fe..56216ef16653c 100644
--- a/lib/AST/RequirementMachine/InterfaceType.cpp
+++ b/lib/AST/RequirementMachine/InterfaceType.cpp
@@ -250,15 +250,14 @@ getTypeForSymbolRange(const Symbol *begin, const Symbol *end,
       unsigned index = GenericParamKey(genericParam).findIndexIn(genericParams);
 
       if (index == genericParams.size()) {
-        llvm::errs() << "Cannot build interface type for term "
-                     << MutableTerm(begin, end) << "\n";
-        llvm::errs() << "Invalid generic parameter: "
-                     << Type(genericParam) << "\n";
-        llvm::errs() << "Valid generic parameters: ";
-        for (auto *otherParam : genericParams)
-          llvm::errs() << " " << otherParam->getCanonicalType();
-        llvm::errs() << "\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Cannot build interface type for term "
+              << MutableTerm(begin, end) << "\n";
+          out << "Invalid generic parameter: " << Type(genericParam) << "\n";
+          out << "Valid generic parameters: ";
+          for (auto *otherParam : genericParams)
+            out << " " << otherParam->getCanonicalType();
+        });
       }
 
       result = genericParams[index];
@@ -281,11 +280,11 @@ getTypeForSymbolRange(const Symbol *begin, const Symbol *end,
         continue;
 
       case Symbol::Kind::Protocol:
-        handleRoot(GenericTypeParamType::getType(0, 0, ctx.getASTContext()));
+        handleRoot(ctx.getASTContext().TheSelfType);
         continue;
 
       case Symbol::Kind::AssociatedType:
-        handleRoot(GenericTypeParamType::getType(0, 0, ctx.getASTContext()));
+        handleRoot(ctx.getASTContext().TheSelfType);
 
         // An associated type symbol at the root means we have a dependent
         // member type rooted at Self; handle the associated type below.
@@ -300,8 +299,9 @@ getTypeForSymbolRange(const Symbol *begin, const Symbol *end,
       case Symbol::Kind::ConcreteType:
       case Symbol::Kind::ConcreteConformance:
       case Symbol::Kind::Shape:
-        llvm::errs() << "Invalid root symbol: " << MutableTerm(begin, end) << "\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Invalid root symbol: " << MutableTerm(begin, end);
+        });
       }
     }
 
@@ -348,12 +348,12 @@ getTypeForSymbolRange(const Symbol *begin, const Symbol *end,
 
     auto *props = map.lookUpProperties(prefix.rbegin(), prefix.rend());
     if (props == nullptr) {
-      llvm::errs() << "Cannot build interface type for term "
-                   << MutableTerm(begin, end) << "\n";
-      llvm::errs() << "Prefix does not conform to any protocols: "
-                   << prefix << "\n\n";
-      map.dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Cannot build interface type for term "
+            << MutableTerm(begin, end) << "\n";
+        out << "Prefix does not conform to any protocols: " << prefix << "\n\n";
+        map.dump(out);
+      });
     }
 
     // Assert that the associated type's protocol appears among the set
@@ -367,16 +367,16 @@ getTypeForSymbolRange(const Symbol *begin, const Symbol *end,
 
     auto *assocType = props->getAssociatedType(symbol.getName());
     if (assocType == nullptr) {
-      llvm::errs() << "Cannot build interface type for term "
-                   << MutableTerm(begin, end) << "\n";
-      llvm::errs() << "Prefix term does not have a nested type named "
-                   << symbol.getName() << ": "
-                   << prefix << "\n";
-      llvm::errs() << "Property map entry: ";
-      props->dump(llvm::errs());
-      llvm::errs() << "\n\n";
-      map.dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Cannot build interface type for term "
+            << MutableTerm(begin, end) << "\n";
+        out << "Prefix term does not have a nested type named "
+            << symbol.getName() << ": " << prefix << "\n";
+        out << "Property map entry: ";
+        props->dump(out);
+        out << "\n\n";
+        map.dump(out);
+      });
     }
 
     result = DependentMemberType::get(result, assocType);
@@ -487,18 +487,18 @@ Type PropertyMap::getTypeFromSubstitutionSchema(
           bool isShapePosition = (pos == TypePosition::Shape);
           bool isShapeTerm = (substitution.back() == Symbol::forShape(Context));
           if (isShapePosition != isShapeTerm) {
-            llvm::errs() << "Shape vs. type mixup\n\n";
-            schema.dump(llvm::errs());
-            llvm::errs() << "Substitutions:\n";
-            for (auto otherSubst : substitutions) {
-              llvm::errs() << "- ";
-              otherSubst.dump(llvm::errs());
-              llvm::errs() << "\n";
-            }
-            llvm::errs() << "\n";
-            dump(llvm::errs());
-
-            abort();
+            ABORT([&](auto &out) {
+              out << "Shape vs. type mixup\n\n";
+              schema.dump(out);
+              out << "Substitutions:\n";
+              for (auto otherSubst : substitutions) {
+                out << "- ";
+                otherSubst.dump(out);
+                out << "\n";
+              }
+              out << "\n";
+              dump(out);
+            });
           }
 
           // Undo the thing where the count type of a PackExpansionType
diff --git a/lib/AST/RequirementMachine/KnuthBendix.cpp b/lib/AST/RequirementMachine/KnuthBendix.cpp
index a0fc682574b63..3b65af8e70847 100644
--- a/lib/AST/RequirementMachine/KnuthBendix.cpp
+++ b/lib/AST/RequirementMachine/KnuthBendix.cpp
@@ -399,7 +399,8 @@ RewriteSystem::performKnuthBendix(unsigned maxRuleCount,
 
           // We don't have to consider the same pair of rules more than once,
           // since those critical pairs were already resolved.
-          if (!CheckedOverlaps.insert(std::make_pair(i, j)).second)
+          unsigned k = from - lhs.getLHS().begin();
+          if (!CheckedOverlaps.insert(std::make_tuple(i, j, k)).second)
             return;
 
           // Try to repair the confluence violation by adding a new rule.
diff --git a/lib/AST/RequirementMachine/MinimalConformances.cpp b/lib/AST/RequirementMachine/MinimalConformances.cpp
index 3bce42b4d49b3..15e69d882d2a8 100644
--- a/lib/AST/RequirementMachine/MinimalConformances.cpp
+++ b/lib/AST/RequirementMachine/MinimalConformances.cpp
@@ -179,9 +179,10 @@ RewriteSystem::decomposeTermIntoConformanceRuleLeftHandSides(
   RewritePath steps;
   bool simplified = simplify(term, &steps);
   if (!simplified) {
-    llvm::errs() << "Term does not conform to protocol: " << term << "\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Term does not conform to protocol: " << term << "\n";
+      dump(out);
+    });
   }
 
   ASSERT(steps.size() == 1 &&
@@ -291,8 +292,9 @@ static const ProtocolDecl *getParentConformanceForTerm(Term lhs) {
     break;
   }
 
-  llvm::errs() << "Bad symbol in " << lhs << "\n";
-  abort();
+  ABORT([&](auto &out) {
+    out << "Bad symbol in " << lhs;
+  });
 }
 
 /// Collect conformance rules and parent paths, and record an initial
@@ -615,19 +617,20 @@ void RewriteSystem::computeCandidateConformancePaths(
           RewritePath rewritePath;
           bool result = simplify(yp, &rewritePath);
           if (!result) {
-            llvm::errs() << "Does not conform to protocol: " << yp << "\n";
-            dump(llvm::errs());
-            abort();
+            ABORT([&](auto &out) {
+              out << "Does not conform to protocol: " << yp << "\n";
+              dump(out);
+            });
           }
 
           if (rewritePath.size() != 1) {
-            llvm::errs() << "Funny rewrite path: ";
+            ABORT([&](auto &out) {
+              out << "Funny rewrite path: ";
 
-            yp = y;
-            yp.add(rhs.getLHS().back());
-            rewritePath.dump(llvm::errs(), yp, *this);
-            llvm::errs() << "\n";
-            abort();
+              yp = y;
+              yp.add(rhs.getLHS().back());
+              rewritePath.dump(out, yp, *this);
+            });
           }
 
           if (rewritePath.begin()->StartOffset == 0) {
@@ -800,15 +803,15 @@ void MinimalConformances::verifyMinimalConformanceEquations() const {
       auto *otherProto = otherRule.getLHS().back().getProtocol();
 
       if (proto != otherProto) {
-        llvm::errs() << "Invalid equation: ";
-        dumpMinimalConformanceEquation(llvm::errs(),
-                                       pair.first, pair.second);
-        llvm::errs() << "\n";
-        llvm::errs() << "Mismatched conformance:\n";
-        llvm::errs() << "Base rule: " << rule << "\n";
-        llvm::errs() << "Final rule: " << otherRule << "\n\n";
-        dumpMinimalConformanceEquations(llvm::errs());
-        abort();
+        ABORT([&](auto &out) {
+          out << "Invalid equation: ";
+          dumpMinimalConformanceEquation(out, pair.first, pair.second);
+          out << "\n";
+          out << "Mismatched conformance:\n";
+          out << "Base rule: " << rule << "\n";
+          out << "Final rule: " << otherRule << "\n\n";
+          dumpMinimalConformanceEquations(out);
+        });
       }
 
       MutableTerm otherTerm;
@@ -819,13 +822,13 @@ void MinimalConformances::verifyMinimalConformanceEquations() const {
         bool isLastElement = (i == path.size() - 1);
         if ((isLastElement && !rule.isAnyConformanceRule()) ||
             (!isLastElement && !rule.isProtocolConformanceRule())) {
-          llvm::errs() << "Equation term is not a conformance rule: ";
-          dumpMinimalConformanceEquation(llvm::errs(),
-                                         pair.first, pair.second);
-          llvm::errs() << "\n";
-          llvm::errs() << "Term: " << rule << "\n";
-          dumpMinimalConformanceEquations(llvm::errs());
-          abort();
+          ABORT([&](auto &out) {
+            out << "Equation term is not a conformance rule: ";
+            dumpMinimalConformanceEquation(out, pair.first, pair.second);
+            out << "\n";
+            out << "Term: " << rule << "\n";
+            dumpMinimalConformanceEquations(out);
+          });
         }
 
         otherTerm.append(rule.getRHS());
@@ -834,15 +837,15 @@ void MinimalConformances::verifyMinimalConformanceEquations() const {
       (void) System.simplify(otherTerm);
 
       if (baseTerm != otherTerm) {
-        llvm::errs() << "Invalid equation: ";
-        dumpMinimalConformanceEquation(llvm::errs(),
-                                       pair.first, pair.second);
-        llvm::errs() << "\n";
-        llvm::errs() << "Invalid conformance path:\n";
-        llvm::errs() << "Expected: " << baseTerm << "\n";
-        llvm::errs() << "Got: " << otherTerm << "\n\n";
-        dumpMinimalConformanceEquations(llvm::errs());
-        abort();
+        ABORT([&](auto &out) {
+          out << "Invalid equation: ";
+          dumpMinimalConformanceEquation(out, pair.first, pair.second);
+          out << "\n";
+          out << "Invalid conformance path:\n";
+          out << "Expected: " << baseTerm << "\n";
+          out << "Got: " << otherTerm << "\n\n";
+          dumpMinimalConformanceEquations(out);
+        });
       }
     }
   }
@@ -941,22 +944,24 @@ void MinimalConformances::verifyMinimalConformances() const {
       llvm::SmallDenseSet<unsigned, 4> visited;
 
       if (!isConformanceRuleRecoverable(visited, ruleID)) {
-        llvm::errs() << "Redundant conformance is not recoverable:\n";
-        llvm::errs() << rule << "\n\n";
-        dumpMinimalConformanceEquations(llvm::errs());
-        dumpMinimalConformances(llvm::errs());
-        abort();
+        ABORT([&](auto &out) {
+          out << "Redundant conformance is not recoverable:\n";
+          out << rule << "\n\n";
+          dumpMinimalConformanceEquations(out);
+          dumpMinimalConformances(out);
+        });
       }
 
       continue;
     }
 
     if (rule.containsNameSymbols()) {
-      llvm::errs() << "Minimal conformance contains unresolved symbols: ";
-      llvm::errs() << rule << "\n\n";
-      dumpMinimalConformanceEquations(llvm::errs());
-      dumpMinimalConformances(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Minimal conformance contains unresolved symbols: ";
+        out << rule << "\n\n";
+        dumpMinimalConformanceEquations(out);
+        dumpMinimalConformances(out);
+      });
     }
   }
 }
diff --git a/lib/AST/RequirementMachine/PropertyMap.cpp b/lib/AST/RequirementMachine/PropertyMap.cpp
index 9f25f4269fdf8..cf4ee4005edc8 100644
--- a/lib/AST/RequirementMachine/PropertyMap.cpp
+++ b/lib/AST/RequirementMachine/PropertyMap.cpp
@@ -364,14 +364,14 @@ PropertyMap::getOrCreateProperties(Term key) {
   Entries.push_back(props);
   auto oldProps = Trie.insert(key.rbegin(), key.rend(), props);
   if (oldProps) {
-    llvm::errs() << "Duplicate property map entry for " << key << "\n";
-    llvm::errs() << "Old:\n";
-    (*oldProps)->dump(llvm::errs());
-    llvm::errs() << "\n";
-    llvm::errs() << "New:\n";
-    props->dump(llvm::errs());
-    llvm::errs() << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Duplicate property map entry for " << key << "\n";
+      out << "Old:\n";
+      (*oldProps)->dump(out);
+      out << "\n";
+      out << "New:\n";
+      props->dump(out);
+    });
   }
 
   return props;
diff --git a/lib/AST/RequirementMachine/PropertyUnification.cpp b/lib/AST/RequirementMachine/PropertyUnification.cpp
index 58d78095c4228..0a15d160a0949 100644
--- a/lib/AST/RequirementMachine/PropertyUnification.cpp
+++ b/lib/AST/RequirementMachine/PropertyUnification.cpp
@@ -221,9 +221,7 @@ void PropertyMap::addLayoutProperty(
 
     props->LayoutRule = ruleID;
   } else {
-    llvm::errs() << "Arbitrary intersection of layout requirements is "
-                 << "supported yet\n";
-    abort();
+    ABORT("Arbitrary intersection of layout requirements isn't supported yet");
   }
 }
 
diff --git a/lib/AST/RequirementMachine/RequirementBuilder.cpp b/lib/AST/RequirementMachine/RequirementBuilder.cpp
index a0bfcccbb7761..21da0433bbf4d 100644
--- a/lib/AST/RequirementMachine/RequirementBuilder.cpp
+++ b/lib/AST/RequirementMachine/RequirementBuilder.cpp
@@ -395,6 +395,9 @@ RequirementMachine::buildRequirementsFromRules(
     bool reconstituteSugar,
     std::vector<Requirement> &reqs,
     std::vector<ProtocolTypeAlias> &aliases) const {
+  if (Failed)
+    return;
+
   RequirementBuilder builder(System, Map, genericParams, reconstituteSugar);
 
   builder.addRequirementRules(requirementRules);
diff --git a/lib/AST/RequirementMachine/RequirementLowering.cpp b/lib/AST/RequirementMachine/RequirementLowering.cpp
index 795fb1218d248..3203d8e93ac37 100644
--- a/lib/AST/RequirementMachine/RequirementLowering.cpp
+++ b/lib/AST/RequirementMachine/RequirementLowering.cpp
@@ -159,6 +159,7 @@
 #include "swift/AST/TypeMatcher.h"
 #include "swift/AST/TypeRepr.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/Basic/Defer.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/SetVector.h"
 #include "Diagnostics.h"
@@ -221,17 +222,15 @@ static void desugarSameTypeRequirement(
         break;
       }
 
-      auto &ctx = firstType->getASTContext();
-      if (!ctx.LangOpts.hasFeature(Feature::SameElementRequirements)) {
-        // If one side is a parameter pack, this is a same-element requirement, which
-        // is not yet supported.
-        if (firstType->isParameterPack() != secondType->isParameterPack()) {
-          errors.push_back(RequirementError::forSameElement(
-              {kind, sugaredFirstType, secondType}, loc));
-          return true;
-        }
+      if (firstType->is<PackExpansionType>() ||
+          secondType->is<PackExpansionType>()) {
+        errors.push_back(RequirementError::forPackSameType(
+            {kind, sugaredFirstType, secondType}, loc));
+        return true;
       }
 
+      auto &ctx = firstType->getASTContext();
+
       if (firstType->isValueParameter() || secondType->isValueParameter()) {
         // FIXME: If we ever support other value types in the future besides
         // 'Int', then we'd want to check their underlying value type to ensure
@@ -264,16 +263,38 @@ static void desugarSameTypeRequirement(
       }
 
       if (firstType->isTypeParameter() && secondType->isTypeParameter()) {
+        if (!ctx.LangOpts.hasFeature(Feature::SameElementRequirements)) {
+          // If one side is a parameter pack, this is a same-element requirement, which
+          // is not yet supported.
+          if (firstType->isParameterPack() != secondType->isParameterPack()) {
+            errors.push_back(RequirementError::forSameElement(
+                {kind, sugaredFirstType, secondType}, loc));
+            return true;
+          }
+        }
+
         result.emplace_back(kind, sugaredFirstType, secondType);
         return true;
       }
 
       if (firstType->isTypeParameter()) {
+        if (firstType->isParameterPack()) {
+          errors.push_back(RequirementError::forPackSameType(
+              {kind, sugaredFirstType, secondType}, loc));
+          return true;
+        }
+
         result.emplace_back(kind, sugaredFirstType, secondType);
         return true;
       }
 
       if (secondType->isTypeParameter()) {
+        if (secondType->isParameterPack()) {
+          errors.push_back(RequirementError::forPackSameType(
+              {kind, sugaredFirstType, secondType}, loc));
+          return true;
+        }
+
         result.emplace_back(kind, secondType, sugaredFirstType);
         return true;
       }
@@ -368,15 +389,6 @@ static void desugarConformanceRequirement(
 
   // Fast path.
   if (constraintType->is<ProtocolType>()) {
-    // Diagnose attempts to introduce a value generic like 'let N: P' where 'P'
-    // is some protocol in either the defining context or in an extension where
-    // clause.
-    if (req.getFirstType()->isValueParameter()) {
-      errors.push_back(
-        RequirementError::forInvalidValueGenericConformance(req, loc));
-      return;
-    }
-
     if (req.getFirstType()->isTypeParameter()) {
       result.push_back(req);
       return;
@@ -450,6 +462,7 @@ static void desugarSameShapeRequirement(
       !req.getSecondType()->isParameterPack()) {
     errors.push_back(RequirementError::forInvalidShapeRequirement(
         req, loc));
+    return;
   }
 
   result.emplace_back(RequirementKind::SameShape,
@@ -511,11 +524,31 @@ void swift::rewriting::desugarRequirements(
 // Requirement realization and inference.
 //
 
-static void realizeTypeRequirement(DeclContext *dc,
-                                   Type subjectType, Type constraintType,
-                                   SourceLoc loc,
-                                   SmallVectorImpl<StructuralRequirement> &result,
-                                   SmallVectorImpl<RequirementError> &errors) {
+void swift::rewriting::realizeTypeRequirement(DeclContext *dc,
+                                 Type subjectType,
+                                 Type constraintType,
+                                 SourceLoc loc,
+                                 SmallVectorImpl<StructuralRequirement> &result,
+                                 SmallVectorImpl<RequirementError> &errors,
+                                 bool isFromInheritanceClause) {
+  // Handle value generics first.
+  if (subjectType->isValueParameter()) {
+    if (isFromInheritanceClause) {
+      if (!constraintType->isLegalValueGenericType()) {
+        // The definition of a generic value parameter has an unsupported type,
+        // e.g. `<let N: UInt8>`.
+        errors.push_back(RequirementError::forInvalidValueGenericType(
+            subjectType, constraintType, loc));
+      }
+    } else {
+      // A generic value parameter was used as the subject of a subtype
+      // constraint, e.g. `N: X` in `struct S<let N: Int> where N: X`.
+      errors.push_back(RequirementError::forInvalidValueGenericConstraint(
+          subjectType, constraintType, loc));
+    }
+    return;
+  }
+
   // The GenericSignatureBuilder allowed the right hand side of a
   // conformance or superclass requirement to reference a protocol
   // typealias whose underlying type was a protocol or class.
@@ -551,22 +584,6 @@ static void realizeTypeRequirement(DeclContext *dc,
     result.push_back({Requirement(RequirementKind::Superclass,
                                   subjectType, constraintType),
                       loc});
-  } else if (subjectType->isValueParameter() && !isa<ExtensionDecl>(dc)) {
-    // This is a correct value generic definition where 'let N: Int'.
-    //
-    // Note: This definition is only valid in non-extension contexts. If we are
-    // in an extension context then the user has written something like:
-    // 'extension T where N: Int' which is weird and not supported.
-    if (constraintType->isLegalValueGenericType()) {
-      return;
-    }
-
-    // Otherwise, we're trying to define a value generic parameter with an
-    // unsupported type right now e.g. 'let N: UInt8'.
-    errors.push_back(
-        RequirementError::forInvalidValueGenericType(subjectType,
-                                                     constraintType,
-                                                     loc));
   } else {
     errors.push_back(
         RequirementError::forInvalidTypeRequirement(subjectType,
@@ -665,7 +682,7 @@ struct InferRequirementsWalker : public TypeWalker {
         auto addSameTypeConstraint = [&](Type firstType,
                                          AssociatedTypeDecl *assocType) {
           auto conformance = lookupConformance(firstType, differentiableProtocol);
-          auto secondType = conformance.getTypeWitness(firstType, assocType);
+          auto secondType = conformance.getTypeWitness(assocType);
           reqs.push_back({Requirement(RequirementKind::SameType,
                                       firstType, secondType),
                           SourceLoc()});
@@ -769,7 +786,8 @@ void swift::rewriting::realizeRequirement(
       inferRequirements(secondType, moduleForInference, dc, result);
     }
 
-    realizeTypeRequirement(dc, firstType, secondType, loc, result, errors);
+    realizeTypeRequirement(dc, firstType, secondType, loc, result, errors,
+                           /*isFromInheritanceClause*/ false);
     break;
   }
 
@@ -798,106 +816,6 @@ void swift::rewriting::realizeRequirement(
   }
 }
 
-void swift::rewriting::applyInverses(
-    ASTContext &ctx,
-    ArrayRef<Type> gps,
-    ArrayRef<InverseRequirement> inverseList,
-    SmallVectorImpl<StructuralRequirement> &result,
-    SmallVectorImpl<RequirementError> &errors) {
-
-  // No inverses to even validate.
-  if (inverseList.empty())
-    return;
-
-  const bool allowInverseOnAssocType =
-      ctx.LangOpts.hasFeature(Feature::SuppressedAssociatedTypes);
-
-  // Summarize the inverses and diagnose ones that are incorrect.
-  llvm::DenseMap<CanType, InvertibleProtocolSet> inverses;
-  for (auto inverse : inverseList) {
-    auto canSubject = inverse.subject->getCanonicalType();
-
-    // Inverses on associated types are experimental.
-    if (!allowInverseOnAssocType && canSubject->is<DependentMemberType>()) {
-      // Special exception: allow if we're building the stdlib.
-      if (!ctx.MainModule->isStdlibModule()) {
-        errors.push_back(RequirementError::forInvalidInverseSubject(inverse));
-        continue;
-      }
-    }
-
-    // Noncopyable checking support for parameter packs is not implemented yet.
-    if (canSubject->isParameterPack()) {
-      errors.push_back(RequirementError::forInvalidInverseSubject(inverse));
-      continue;
-    }
-
-    // Value generics never have inverse requirements (or the positive thereof).
-    if (canSubject->isValueParameter()) {
-      continue;
-    }
-
-    // WARNING: possible quadratic behavior, but should be OK in practice.
-    auto notInScope = llvm::none_of(gps, [=](Type t) {
-      return t->getCanonicalType() == canSubject;
-    });
-
-    // If the inverse is on a subject that wasn't permitted by our caller, then
-    // remove and diagnose as an error. This can happen when an inner context
-    // has a constraint on some outer generic parameter, e.g.,
-    //
-    //     protocol P {
-    //       func f() where Self: ~Copyable
-    //     }
-    //
-    if (notInScope) {
-      errors.push_back(
-          RequirementError::forInvalidInverseOuterSubject(inverse));
-      continue;
-    }
-
-    auto state = inverses.getOrInsertDefault(canSubject);
-
-    // Check if this inverse has already been seen.
-    auto inverseKind = inverse.getKind();
-    if (state.contains(inverseKind))
-      continue;
-
-    state.insert(inverseKind);
-    inverses[canSubject] = state;
-  }
-
-  // Fast-path: if there are no valid inverses, then there are no requirements
-  // to be removed.
-  if (inverses.empty())
-    return;
-
-  // Scan the structural requirements and cancel out any inferred requirements
-  // based on the inverses we saw.
-  result.erase(llvm::remove_if(result, [&](StructuralRequirement structReq) {
-    auto req = structReq.req;
-
-    if (req.getKind() != RequirementKind::Conformance)
-      return false;
-
-    // Only consider requirements involving an invertible protocol.
-    auto proto = req.getProtocolDecl()->getInvertibleProtocolKind();
-    if (!proto)
-      return false;
-
-    // See if this subject is in-scope.
-    auto subject = req.getFirstType()->getCanonicalType();
-    auto result = inverses.find(subject);
-    if (result == inverses.end())
-      return false;
-
-    // We now have found the inferred constraint 'Subject : Proto'.
-    // So, remove it if we have recorded a 'Subject : ~Proto'.
-    auto recordedInverses = result->getSecond();
-    return recordedInverses.contains(*proto);
-  }), result.end());
-}
-
 /// Collect structural requirements written in the inheritance clause of an
 /// AssociatedTypeDecl, GenericTypeParamDecl, or ProtocolDecl.
 void swift::rewriting::realizeInheritedRequirements(
@@ -922,7 +840,8 @@ void swift::rewriting::realizeInheritedRequirements(
     auto *typeRepr = inheritedTypes.getTypeRepr(index);
     SourceLoc loc = (typeRepr ? typeRepr->getStartLoc() : SourceLoc());
 
-    realizeTypeRequirement(dc, type, inheritedType, loc, result, errors);
+    realizeTypeRequirement(dc, type, inheritedType, loc, result, errors,
+                           /*isFromInheritanceClause*/ true);
   }
 
   // Also check for `SynthesizedProtocolAttr`s with additional constraints added
@@ -933,7 +852,8 @@ void swift::rewriting::realizeInheritedRequirements(
     auto inheritedType = attr->getProtocol()->getDeclaredType();
     auto loc = attr->getLocation();
 
-    realizeTypeRequirement(dc, type, inheritedType, loc, result, errors);
+    realizeTypeRequirement(dc, type, inheritedType, loc, result, errors,
+                           /*isFromInheritanceClause*/ false);
   }
 }
 
@@ -1002,7 +922,8 @@ StructuralRequirementsRequest::evaluate(Evaluator &evaluator,
 
     SmallVector<StructuralRequirement, 2> defaults;
     InverseRequirement::expandDefaults(ctx, needsDefaultRequirements, defaults);
-    applyInverses(ctx, needsDefaultRequirements, inverses, defaults, errors);
+    applyInverses(ctx, needsDefaultRequirements, inverses, result,
+                  defaults, errors);
     result.append(defaults);
 
     diagnoseRequirementErrors(ctx, errors,
@@ -1076,7 +997,8 @@ StructuralRequirementsRequest::evaluate(Evaluator &evaluator,
       && !proto->isSpecificProtocol(KnownProtocolKind::Sendable))
     InverseRequirement::expandDefaults(ctx, needsDefaultRequirements, defaults);
 
-  applyInverses(ctx, needsDefaultRequirements, inverses, defaults, errors);
+  applyInverses(ctx, needsDefaultRequirements, inverses, result,
+                defaults, errors);
   result.append(defaults);
 
   diagnoseRequirementErrors(ctx, errors,
@@ -1267,9 +1189,7 @@ TypeAliasRequirementsRequest::evaluate(Evaluator &evaluator,
           inheritedType->getDeclContext()->getSelfNominalTypeDecl();
       ctx.Diags.diagnose(assocTypeDecl,
                          diag::associated_type_override_typealias,
-                         assocTypeDecl->getName(),
-                         inheritedOwningDecl->getDescriptiveKind(),
-                         inheritedOwningDecl->getDeclaredInterfaceType());
+                         assocTypeDecl->getName(), inheritedOwningDecl);
 
       recordInheritedTypeRequirement(assocTypeDecl, inheritedType);
     }
diff --git a/lib/AST/RequirementMachine/RequirementLowering.h b/lib/AST/RequirementMachine/RequirementLowering.h
index 1f3fbc57ad961..f0626beaaf9c3 100644
--- a/lib/AST/RequirementMachine/RequirementLowering.h
+++ b/lib/AST/RequirementMachine/RequirementLowering.h
@@ -50,6 +50,14 @@ void desugarRequirement(Requirement req, SourceLoc loc,
 void inferRequirements(Type type, ModuleDecl *module, DeclContext *dc,
                        SmallVectorImpl<StructuralRequirement> &result);
 
+void realizeTypeRequirement(DeclContext *dc,
+                            Type subjectType,
+                            Type constraintType,
+                            SourceLoc loc,
+                            SmallVectorImpl<StructuralRequirement> &result,
+                            SmallVectorImpl<RequirementError> &errors,
+                            bool isFromInheritanceClause);
+
 void realizeRequirement(DeclContext *dc,
                         Requirement req, RequirementRepr *reqRepr,
                         bool shouldInferRequirements,
@@ -64,6 +72,7 @@ void realizeInheritedRequirements(TypeDecl *decl, Type type,
 void applyInverses(ASTContext &ctx,
                    ArrayRef<Type> gps,
                    ArrayRef<InverseRequirement> inverseList,
+                   ArrayRef<StructuralRequirement> explicitRequirements,
                    SmallVectorImpl<StructuralRequirement> &result,
                    SmallVectorImpl<RequirementError> &errors);
 
diff --git a/lib/AST/RequirementMachine/RequirementMachine.cpp b/lib/AST/RequirementMachine/RequirementMachine.cpp
index 1fa52060f0c4f..c5a37777a87c0 100644
--- a/lib/AST/RequirementMachine/RequirementMachine.cpp
+++ b/lib/AST/RequirementMachine/RequirementMachine.cpp
@@ -212,6 +212,8 @@ RequirementMachine::RequirementMachine(RewriteContext &ctx)
   MaxRuleCount = langOpts.RequirementMachineMaxRuleCount;
   MaxRuleLength = langOpts.RequirementMachineMaxRuleLength;
   MaxConcreteNesting = langOpts.RequirementMachineMaxConcreteNesting;
+  MaxConcreteSize = langOpts.RequirementMachineMaxConcreteSize;
+  MaxTypeDifferences = langOpts.RequirementMachineMaxTypeDifferences;
   Stats = ctx.getASTContext().Stats;
 
   if (Stats)
@@ -231,19 +233,34 @@ void RequirementMachine::checkCompletionResult(CompletionResult result) const {
     break;
 
   case CompletionResult::MaxRuleCount:
-    llvm::errs() << "Rewrite system exceeded maximum rule count\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Rewrite system exceeded maximum rule count\n";
+      dump(out);
+    });
 
   case CompletionResult::MaxRuleLength:
-    llvm::errs() << "Rewrite system exceeded rule length limit\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Rewrite system exceeded rule length limit\n";
+      dump(out);
+    });
 
   case CompletionResult::MaxConcreteNesting:
-    llvm::errs() << "Rewrite system exceeded concrete type nesting depth limit\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Rewrite system exceeded concrete type nesting depth limit\n";
+      dump(out);
+    });
+
+  case CompletionResult::MaxConcreteSize:
+    ABORT([&](auto &out) {
+      out << "Rewrite system exceeded concrete type size limit\n";
+      dump(out);
+    });
+
+  case CompletionResult::MaxTypeDifferences:
+    ABORT([&](auto &out) {
+      out << "Rewrite system exceeded concrete type difference limit\n";
+      dump(out);
+    });
   }
 }
 
@@ -272,6 +289,9 @@ RequirementMachine::initWithProtocolSignatureRequirements(
   RuleBuilder builder(Context, System.getReferencedProtocols());
   builder.initWithProtocolSignatureRequirements(protos);
 
+  // Remember if any of our upstream protocols failed to complete.
+  Failed = builder.Failed;
+
   // Add the initial set of rewrite rules to the rewrite system.
   System.initialize(/*recordLoops=*/false, protos,
                     std::move(builder.ImportedRules),
@@ -320,6 +340,9 @@ RequirementMachine::initWithGenericSignature(GenericSignature sig) {
   builder.initWithGenericSignature(sig.getGenericParams(),
                                    sig.getRequirements());
 
+  // Remember if any of our upstream protocols failed to complete.
+  Failed = builder.Failed;
+
   // Add the initial set of rewrite rules to the rewrite system.
   System.initialize(/*recordLoops=*/false,
                     /*protos=*/ArrayRef<const ProtocolDecl *>(),
@@ -373,6 +396,9 @@ RequirementMachine::initWithProtocolWrittenRequirements(
   RuleBuilder builder(Context, System.getReferencedProtocols());
   builder.initWithProtocolWrittenRequirements(component, protos);
 
+  // Remember if any of our upstream protocols failed to complete.
+  Failed = builder.Failed;
+
   // Add the initial set of rewrite rules to the rewrite system.
   System.initialize(/*recordLoops=*/true, component,
                     std::move(builder.ImportedRules),
@@ -420,6 +446,9 @@ RequirementMachine::initWithWrittenRequirements(
   RuleBuilder builder(Context, System.getReferencedProtocols());
   builder.initWithWrittenRequirements(genericParams, requirements);
 
+  // Remember if any of our upstream protocols failed to complete.
+  Failed = builder.Failed;
+
   // Add the initial set of rewrite rules to the rewrite system.
   System.initialize(/*recordLoops=*/true,
                     /*protos=*/ArrayRef<const ProtocolDecl *>(),
@@ -493,16 +522,26 @@ RequirementMachine::computeCompletion(RewriteSystem::ValidityPolicy policy) {
           return std::make_pair(CompletionResult::MaxRuleLength,
                                 ruleCount + i);
         }
-        if (newRule.getNesting() > MaxConcreteNesting + System.getDeepestInitialRule()) {
+        auto nestingAndSize = newRule.getNestingAndSize();
+        if (nestingAndSize.first > MaxConcreteNesting + System.getMaxNestingOfInitialRule()) {
           return std::make_pair(CompletionResult::MaxConcreteNesting,
                                 ruleCount + i);
         }
+        if (nestingAndSize.second > MaxConcreteSize + System.getMaxSizeOfInitialRule()) {
+          return std::make_pair(CompletionResult::MaxConcreteSize,
+                                ruleCount + i);
+        }
       }
 
       if (System.getLocalRules().size() > MaxRuleCount) {
         return std::make_pair(CompletionResult::MaxRuleCount,
                               System.getRules().size() - 1);
       }
+
+      if (System.getTypeDifferenceCount() > MaxTypeDifferences) {
+        return std::make_pair(CompletionResult::MaxTypeDifferences,
+                              System.getRules().size() - 1);
+      }
     }
   }
 
@@ -526,10 +565,6 @@ ArrayRef<Rule> RequirementMachine::getLocalRules() const {
   return System.getLocalRules();
 }
 
-bool RequirementMachine::isComplete() const {
-  return Complete;
-}
-
 GenericSignatureErrors RequirementMachine::getErrors() const {
   // FIXME: Assert if we had errors but we didn't emit any diagnostics?
   return System.getErrors();
diff --git a/lib/AST/RequirementMachine/RequirementMachine.h b/lib/AST/RequirementMachine/RequirementMachine.h
index c64248e978f6e..1b1592bd5c51b 100644
--- a/lib/AST/RequirementMachine/RequirementMachine.h
+++ b/lib/AST/RequirementMachine/RequirementMachine.h
@@ -64,10 +64,19 @@ class RequirementMachine final {
   bool Dump = false;
   bool Complete = false;
 
+  /// Whether completion failed, either for this rewrite system, or one of
+  /// its imported protocols. In this case, name lookup might find type
+  /// parameters that are not valid according to the rewrite system, because
+  /// not all conformance requirements will be present. This flag allows
+  /// us to skip certain verification checks in that case.
+  bool Failed = false;
+
   /// Parameters to prevent runaway completion and property map construction.
   unsigned MaxRuleCount;
   unsigned MaxRuleLength;
   unsigned MaxConcreteNesting;
+  unsigned MaxConcreteSize;
+  unsigned MaxTypeDifferences;
 
   UnifiedStatsReporter *Stats;
 
@@ -108,7 +117,9 @@ class RequirementMachine final {
       ArrayRef<GenericTypeParamType *> genericParams,
       ArrayRef<StructuralRequirement> requirements);
 
-  bool isComplete() const;
+  bool isComplete() const {
+    return Complete;
+  }
 
   std::pair<CompletionResult, unsigned>
   computeCompletion(RewriteSystem::ValidityPolicy policy);
@@ -137,6 +148,10 @@ class RequirementMachine final {
 public:
   ~RequirementMachine();
 
+  bool isFailed() const {
+    return Failed;
+  }
+
   // Generic signature queries. Generally you shouldn't have to construct a
   // RequirementMachine instance; instead, call the corresponding methods on
   // GenericSignature, which lazily create a RequirementMachine for you.
diff --git a/lib/AST/RequirementMachine/RequirementMachineRequests.cpp b/lib/AST/RequirementMachine/RequirementMachineRequests.cpp
index 83f06a1538ef6..28ec01d43c5ec 100644
--- a/lib/AST/RequirementMachine/RequirementMachineRequests.cpp
+++ b/lib/AST/RequirementMachine/RequirementMachineRequests.cpp
@@ -163,15 +163,16 @@ static void splitConcreteEquivalenceClasses(
       ctx.LangOpts.RequirementMachineMaxSplitConcreteEquivClassAttempts;
 
   if (attempt >= maxAttempts) {
-    llvm::errs() << "Splitting concrete equivalence classes did not "
-                 << "reach fixed point after " << attempt << " attempts.\n";
-    llvm::errs() << "Last attempt produced these requirements:\n";
-    for (auto req : requirements) {
-      req.dump(llvm::errs());
-      llvm::errs() << "\n";
-    }
-    machine->dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Splitting concrete equivalence classes did not "
+          << "reach fixed point after " << attempt << " attempts.\n";
+      out << "Last attempt produced these requirements:\n";
+      for (auto req : requirements) {
+        req.dump(out);
+        out << "\n";
+      }
+      machine->dump(out);
+    });
   }
 
   splitRequirements.clear();
@@ -628,7 +629,7 @@ AbstractGenericSignatureRequest::evaluate(
             }
             return Type(type);
           },
-          MakeAbstractConformanceForGenericType(),
+          LookUpConformanceInModule(),
           SubstFlags::PreservePackExpansionLevel);
       resugaredRequirements.push_back(resugaredReq);
     }
@@ -671,7 +672,8 @@ AbstractGenericSignatureRequest::evaluate(
 
   SmallVector<StructuralRequirement, 2> defaults;
   InverseRequirement::expandDefaults(ctx, paramsAsTypes, defaults);
-  applyInverses(ctx, paramsAsTypes, inverses, defaults, errors);
+  applyInverses(ctx, paramsAsTypes, inverses, requirements,
+                defaults, errors);
   requirements.append(defaults);
 
   auto &rewriteCtx = ctx.getRewriteContext();
@@ -748,26 +750,6 @@ AbstractGenericSignatureRequest::evaluate(
   }
 }
 
-/// If completion fails, build a dummy generic signature where everything is
-/// Copyable and Escapable, to avoid spurious downstream diagnostics
-/// concerning move-only types.
-static GenericSignature getPlaceholderGenericSignature(
-    ASTContext &ctx, ArrayRef<GenericTypeParamType *> genericParams) {
-  SmallVector<Requirement, 2> requirements;
-  for (auto param : genericParams) {
-    if (param->isValue())
-      continue;
-
-    for (auto ip : InvertibleProtocolSet::allKnown()) {
-      auto proto = ctx.getProtocol(getKnownProtocolKind(ip));
-      requirements.emplace_back(RequirementKind::Conformance, param,
-                                proto->getDeclaredInterfaceType());
-    }
-  }
-
-  return GenericSignature::get(genericParams, requirements);
-}
-
 GenericSignatureWithError
 InferredGenericSignatureRequest::evaluate(
         Evaluator &evaluator,
@@ -870,7 +852,7 @@ InferredGenericSignatureRequest::evaluate(
   // inferred same-type requirements when building the generic signature of
   // an extension whose extended type is a generic typealias.
   for (const auto &req : addedRequirements)
-    requirements.push_back({req, SourceLoc()});
+    requirements.push_back({req, loc});
 
   desugarRequirements(requirements, inverses, errors);
 
@@ -884,7 +866,8 @@ InferredGenericSignatureRequest::evaluate(
 
   SmallVector<StructuralRequirement, 2> defaults;
   InverseRequirement::expandDefaults(ctx, paramTypes, defaults);
-  applyInverses(ctx, paramTypes, inverses, defaults, errors);
+  applyInverses(ctx, paramTypes, inverses, requirements,
+                defaults, errors);
   
   // Any remaining implicit defaults in a conditional inverse requirement
   // extension must be made explicit.
@@ -993,7 +976,7 @@ InferredGenericSignatureRequest::evaluate(
                          diag::requirement_machine_completion_rule,
                          rule);
 
-      auto result = getPlaceholderGenericSignature(ctx, genericParams);
+      auto result = GenericSignature::forInvalid(genericParams);
 
       if (rewriteCtx.getDebugOptions().contains(DebugFlags::Timers)) {
         rewriteCtx.endTimer("InferredGenericSignatureRequest");
diff --git a/lib/AST/RequirementMachine/RewriteContext.cpp b/lib/AST/RequirementMachine/RewriteContext.cpp
index c739df898d356..d9d1564b18164 100644
--- a/lib/AST/RequirementMachine/RewriteContext.cpp
+++ b/lib/AST/RequirementMachine/RewriteContext.cpp
@@ -267,9 +267,9 @@ RequirementMachine *RewriteContext::getRequirementMachine(
   auto &machine = Machines[sig];
   if (machine) {
     if (!machine->isComplete()) {
-      llvm::errs() << "Re-entrant construction of requirement "
-                   << "machine for " << sig << "\n";
-      abort();
+      ABORT([&](auto &out) {
+        out << "Re-entrant construction of requirement machine for " << sig;
+      });
     }
 
     return machine;
@@ -433,10 +433,8 @@ RewriteContext::getProtocolComponentImpl(const ProtocolDecl *proto) {
 
   auto found = Protos.find(proto);
   if (found == Protos.end()) {
-    if (ProtectProtocolComponentRec) {
-      llvm::errs() << "Too much recursion is bad\n";
-      abort();
-    }
+    if (ProtectProtocolComponentRec)
+      ABORT("Too much recursion is bad");
 
     ProtectProtocolComponentRec = true;
 
@@ -469,11 +467,11 @@ RewriteContext::startComputingRequirementSignatures(
   auto &component = getProtocolComponentImpl(proto);
 
   if (component.ComputingRequirementSignatures) {
-    llvm::errs() << "Re-entrant minimization of requirement signatures for: ";
-    for (auto *proto : component.Protos)
-      llvm::errs() << " " << proto->getName();
-    llvm::errs() << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Re-entrant minimization of requirement signatures for: ";
+      for (auto *proto : component.Protos)
+        out << " " << proto->getName();
+    });
   }
 
   component.ComputingRequirementSignatures = true;
@@ -508,11 +506,11 @@ RequirementMachine *RewriteContext::getRequirementMachine(
 
   if (component.Machine) {
     if (!component.Machine->isComplete()) {
-      llvm::errs() << "Re-entrant construction of requirement machine for: ";
-      for (auto *proto : component.Protos)
-        llvm::errs() << " " << proto->getName();
-      llvm::errs() << "\n";
-      abort();
+      ABORT([&](auto &out) {
+        out << "Re-entrant construction of requirement machine for: ";
+        for (auto *proto : component.Protos)
+          out << " " << proto->getName();
+      });
     }
 
     return component.Machine;
diff --git a/lib/AST/RequirementMachine/RewriteLoop.cpp b/lib/AST/RequirementMachine/RewriteLoop.cpp
index 9c373e3729820..ef5a661d3e18b 100644
--- a/lib/AST/RequirementMachine/RewriteLoop.cpp
+++ b/lib/AST/RequirementMachine/RewriteLoop.cpp
@@ -430,16 +430,17 @@ void RewriteLoop::verify(const RewriteSystem &system) const {
   }
 
   if (evaluator.getCurrentTerm() != Basepoint) {
-    llvm::errs() << "Not a loop: ";
-    dump(llvm::errs(), system);
-    llvm::errs() << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Not a loop: ";
+      dump(out, system);
+    });
   }
 
   if (evaluator.isInContext()) {
-    llvm::errs() << "Leftover terms on evaluator stack\n";
-    evaluator.dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Leftover terms on evaluator stack\n";
+      evaluator.dump(out);
+    });
   }
 }
 
@@ -555,17 +556,19 @@ void RewritePathEvaluator::dump(llvm::raw_ostream &out) const {
 
 void RewritePathEvaluator::checkPrimary() const {
   if (Primary.empty()) {
-    llvm::errs() << "Empty primary stack\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Empty primary stack\n";
+      dump(out);
+    });
   }
 }
 
 void RewritePathEvaluator::checkSecondary() const {
   if (Secondary.empty()) {
-    llvm::errs() << "Empty secondary stack\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Empty secondary stack\n";
+      dump(out);
+    });
   }
 }
 
@@ -587,12 +590,13 @@ RewritePathEvaluator::applyRewriteRule(const RewriteStep &step,
   auto rhs = (step.Inverse ? rule.getLHS() : rule.getRHS());
 
   auto bug = [&](StringRef msg) {
-    llvm::errs() << msg << "\n";
-    llvm::errs() << "- Term: " << term << "\n";
-    llvm::errs() << "- StartOffset: " << step.StartOffset << "\n";
-    llvm::errs() << "- EndOffset: " << step.EndOffset << "\n";
-    llvm::errs() << "- Expected subterm: " << lhs << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << msg << "\n";
+      out << "- Term: " << term << "\n";
+      out << "- StartOffset: " << step.StartOffset << "\n";
+      out << "- EndOffset: " << step.EndOffset << "\n";
+      out << "- Expected subterm: " << lhs;
+    });
   };
 
   if (term.size() != step.StartOffset + lhs.size() + step.EndOffset) {
@@ -632,11 +636,12 @@ RewritePathEvaluator::applyPrefixSubstitutions(const RewriteStep &step,
   // We're either adding or removing the prefix to each concrete substitution.
   Symbol &last = *(term.end() - step.EndOffset - 1);
   if (!last.hasSubstitutions()) {
-    llvm::errs() << "Invalid rewrite path\n";
-    llvm::errs() << "- Term: " << term << "\n";
-    llvm::errs() << "- Start offset: " << step.StartOffset << "\n";
-    llvm::errs() << "- End offset: " << step.EndOffset << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Invalid rewrite path\n";
+      out << "- Term: " << term << "\n";
+      out << "- Start offset: " << step.StartOffset << "\n";
+      out << "- End offset: " << step.EndOffset;
+    });
   }
 
   last = last.transformConcreteSubstitutions(
@@ -645,13 +650,14 @@ RewritePathEvaluator::applyPrefixSubstitutions(const RewriteStep &step,
         if (!std::equal(t.begin(),
                         t.begin() + step.Arg,
                         prefix.begin())) {
-          llvm::errs() << "Invalid rewrite path\n";
-          llvm::errs() << "- Term: " << term << "\n";
-          llvm::errs() << "- Substitution: " << t << "\n";
-          llvm::errs() << "- Start offset: " << step.StartOffset << "\n";
-          llvm::errs() << "- End offset: " << step.EndOffset << "\n";
-          llvm::errs() << "- Expected subterm: " << prefix << "\n";
-          abort();
+          ABORT([&](auto &out) {
+            out << "Invalid rewrite path\n";
+            out << "- Term: " << term << "\n";
+            out << "- Substitution: " << t << "\n";
+            out << "- Start offset: " << step.StartOffset << "\n";
+            out << "- End offset: " << step.EndOffset << "\n";
+            out << "- Expected subterm: " << prefix;
+          });
         }
 
         MutableTerm mutTerm(t.begin() + step.Arg, t.end());
@@ -698,17 +704,19 @@ void RewritePathEvaluator::applyDecompose(const RewriteStep &step,
     const auto &term = getCurrentTerm();
     auto symbol = *(term.end() - step.EndOffset - 1);
     if (!symbol.hasSubstitutions()) {
-      llvm::errs() << "Expected term with superclass or concrete type symbol"
-                   << " on primary stack\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Expected term with superclass or concrete type symbol"
+            << " on primary stack\n";
+        dump(out);
+      });
     }
 
     // The symbol must have the expected number of substitutions.
     if (symbol.getSubstitutions().size() != numSubstitutions) {
-      llvm::errs() << "Expected " << numSubstitutions << " substitutions\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Expected " << numSubstitutions << " substitutions\n";
+        dump(out);
+      });
     }
 
     // Push each substitution on the primary stack.
@@ -720,9 +728,10 @@ void RewritePathEvaluator::applyDecompose(const RewriteStep &step,
     // a term that takes the form U.[concrete: C].V or U.[superclass: C].V,
     // where |V| == EndOffset.
     if (Primary.size() < numSubstitutions + 1) {
-      llvm::errs() << "Not enough terms on primary stack\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Not enough terms on primary stack\n";
+        dump(out);
+      });
     }
 
     // The term immediately underneath the substitutions is the one we're
@@ -733,18 +742,20 @@ void RewritePathEvaluator::applyDecompose(const RewriteStep &step,
     // The symbol at the end of this term must have the expected number of
     // substitutions.
     if (symbol.getSubstitutions().size() != numSubstitutions) {
-      llvm::errs() << "Expected " << numSubstitutions << " substitutions\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Expected " << numSubstitutions << " substitutions\n";
+        dump(out);
+      });
     }
 
     for (unsigned i = 0; i < numSubstitutions; ++i) {
       const auto &substitution = *(Primary.end() - numSubstitutions + i);
       if (MutableTerm(symbol.getSubstitutions()[i]) != substitution) {
-        llvm::errs() << "Expected " << symbol.getSubstitutions()[i] << "\n";
-        llvm::errs() << "Got " << substitution << "\n";
-        dump(llvm::errs());
-        abort();
+        ABORT([&](auto &out) {
+          out << "Expected " << symbol.getSubstitutions()[i] << "\n";
+          out << "Got " << substitution << "\n";
+          dump(out);
+        });
       }
     }
 
@@ -765,12 +776,13 @@ RewritePathEvaluator::applyRelation(const RewriteStep &step,
   auto rhs = (step.Inverse ? relation.first : relation.second);
 
   auto bug = [&](StringRef msg) {
-    llvm::errs() << msg << "\n";
-    llvm::errs() << "- Term: " << term << "\n";
-    llvm::errs() << "- StartOffset: " << step.StartOffset << "\n";
-    llvm::errs() << "- EndOffset: " << step.EndOffset << "\n";
-    llvm::errs() << "- Expected subterm: " << lhs << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << msg << "\n";
+      out << "- Term: " << term << "\n";
+      out << "- StartOffset: " << step.StartOffset << "\n";
+      out << "- EndOffset: " << step.EndOffset << "\n";
+      out << "- Expected subterm: " << lhs << "\n";
+    });
   };
 
   if (term.size() != step.StartOffset + lhs.size() + step.EndOffset) {
@@ -799,15 +811,16 @@ void RewritePathEvaluator::applyDecomposeConcrete(const RewriteStep &step,
 
   const auto &difference = system.getTypeDifference(step.Arg);
   auto bug = [&](StringRef msg) {
-    llvm::errs() << msg << "\n";
-    llvm::errs() << "- StartOffset: " << step.StartOffset << "\n";
-    llvm::errs() << "- EndOffset: " << step.EndOffset << "\n";
-    llvm::errs() << "- DifferenceID: " << step.Arg << "\n";
-    llvm::errs() << "\nType difference:\n";
-    difference.dump(llvm::errs());
-    llvm::errs() << "\nEvaluator state:\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << msg << "\n";
+      out << "- StartOffset: " << step.StartOffset << "\n";
+      out << "- EndOffset: " << step.EndOffset << "\n";
+      out << "- DifferenceID: " << step.Arg << "\n";
+      out << "\nType difference:\n";
+      difference.dump(out);
+      out << "\nEvaluator state:\n";
+      dump(out);
+    });
   };
 
   auto substitutions = difference.LHS.getSubstitutions();
@@ -837,9 +850,12 @@ void RewritePathEvaluator::applyDecomposeConcrete(const RewriteStep &step,
       const auto &otherSubstitution = *(Primary.end() - numSubstitutions + n);
       auto expectedSubstitution = difference.getReplacementSubstitution(n);
       if (otherSubstitution != expectedSubstitution) {
-        llvm::errs() << "Got: " << otherSubstitution << "\n";
-        llvm::errs() << "Expected: " << expectedSubstitution << "\n";
-        bug("Unexpected substitution term on the stack");
+        SmallString<0> message;
+        llvm::raw_svector_ostream out(message);
+        out << "Unexpected substitution term on the stack\n";
+        out << "Got: " << otherSubstitution << "\n";
+        out << "Expected: " << expectedSubstitution << "\n";
+        bug(message);
       }
     }
 
@@ -872,20 +888,21 @@ RewritePathEvaluator::applyLeftConcreteProjection(const RewriteStep &step,
   leftBaseTerm.add(difference.LHS);
 
   auto bug = [&](StringRef msg) {
-    llvm::errs() << msg << "\n";
-    llvm::errs() << "- StartOffset: " << step.StartOffset << "\n";
-    llvm::errs() << "- EndOffset: " << step.EndOffset << "\n";
-    llvm::errs() << "- SubstitutionIndex: " << index << "\n";
-    llvm::errs() << "- LeftProjection: " << leftProjection << "\n";
-    llvm::errs() << "- LeftBaseTerm: " << leftBaseTerm << "\n";
-    llvm::errs() << "- DifferenceID: " << step.getTypeDifferenceID() << "\n";
-    llvm::errs() << "\nType difference:\n";
-    difference.dump(llvm::errs());
-    llvm::errs() << ":\n";
-    difference.dump(llvm::errs());
-    llvm::errs() << "\nEvaluator state:\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << msg << "\n";
+      out << "- StartOffset: " << step.StartOffset << "\n";
+      out << "- EndOffset: " << step.EndOffset << "\n";
+      out << "- SubstitutionIndex: " << index << "\n";
+      out << "- LeftProjection: " << leftProjection << "\n";
+      out << "- LeftBaseTerm: " << leftBaseTerm << "\n";
+      out << "- DifferenceID: " << step.getTypeDifferenceID() << "\n";
+      out << "\nType difference:\n";
+      difference.dump(out);
+      out << ":\n";
+      difference.dump(out);
+      out << "\nEvaluator state:\n";
+      dump(out);
+    });
   };
 
   if (!step.Inverse) {
@@ -933,20 +950,21 @@ RewritePathEvaluator::applyRightConcreteProjection(const RewriteStep &step,
   rightBaseTerm.add(difference.RHS);
 
   auto bug = [&](StringRef msg) {
-    llvm::errs() << msg << "\n";
-    llvm::errs() << "- StartOffset: " << step.StartOffset << "\n";
-    llvm::errs() << "- EndOffset: " << step.EndOffset << "\n";
-    llvm::errs() << "- SubstitutionIndex: " << index << "\n";
-    llvm::errs() << "- LeftProjection: " << leftProjection << "\n";
-    llvm::errs() << "- RightProjection: " << rightProjection << "\n";
-    llvm::errs() << "- LeftBaseTerm: " << leftBaseTerm << "\n";
-    llvm::errs() << "- RightBaseTerm: " << rightBaseTerm << "\n";
-    llvm::errs() << "- DifferenceID: " << step.getTypeDifferenceID() << "\n";
-    llvm::errs() << "\nType difference:\n";
-    difference.dump(llvm::errs());
-    llvm::errs() << "\nEvaluator state:\n";
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << msg << "\n";
+      out << "- StartOffset: " << step.StartOffset << "\n";
+      out << "- EndOffset: " << step.EndOffset << "\n";
+      out << "- SubstitutionIndex: " << index << "\n";
+      out << "- LeftProjection: " << leftProjection << "\n";
+      out << "- RightProjection: " << rightProjection << "\n";
+      out << "- LeftBaseTerm: " << leftBaseTerm << "\n";
+      out << "- RightBaseTerm: " << rightBaseTerm << "\n";
+      out << "- DifferenceID: " << step.getTypeDifferenceID() << "\n";
+      out << "\nType difference:\n";
+      difference.dump(out);
+      out << "\nEvaluator state:\n";
+      dump(out);
+    });
   };
 
   if (!step.Inverse) {
diff --git a/lib/AST/RequirementMachine/RewriteSystem.cpp b/lib/AST/RequirementMachine/RewriteSystem.cpp
index 6be27b082a240..ac4dda392d95a 100644
--- a/lib/AST/RequirementMachine/RewriteSystem.cpp
+++ b/lib/AST/RequirementMachine/RewriteSystem.cpp
@@ -34,7 +34,8 @@ RewriteSystem::RewriteSystem(RewriteContext &ctx)
   Frozen = 0;
   RecordLoops = 0;
   LongestInitialRule = 0;
-  DeepestInitialRule = 0;
+  MaxNestingOfInitialRule = 0;
+  MaxSizeOfInitialRule = 0;
 }
 
 RewriteSystem::~RewriteSystem() {
@@ -90,7 +91,12 @@ void RewriteSystem::initialize(
 
   for (const auto &rule : getLocalRules()) {
     LongestInitialRule = std::max(LongestInitialRule, rule.getDepth());
-    DeepestInitialRule = std::max(DeepestInitialRule, rule.getNesting());
+
+    auto nestingAndSize = rule.getNestingAndSize();
+    MaxNestingOfInitialRule = std::max(MaxNestingOfInitialRule,
+                                      nestingAndSize.first);
+    MaxSizeOfInitialRule = std::max(MaxSizeOfInitialRule,
+                                    nestingAndSize.second);
   }
 }
 
@@ -261,17 +267,18 @@ bool RewriteSystem::addRule(MutableTerm lhs, MutableTerm rhs,
 
   auto oldRuleID = Trie.insert(lhs.begin(), lhs.end(), newRuleID);
   if (oldRuleID) {
-    llvm::errs() << "Duplicate rewrite rule!\n";
-    const auto &oldRule = getRule(*oldRuleID);
-    llvm::errs() << "Old rule #" << *oldRuleID << ": ";
-    oldRule.dump(llvm::errs());
-    llvm::errs() << "\nTrying to replay what happened when I simplified this term:\n";
-    Debug |= DebugFlags::Simplify;
-    MutableTerm term = lhs;
-    simplify(lhs);
-
-    dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Duplicate rewrite rule!\n";
+      const auto &oldRule = getRule(*oldRuleID);
+      out << "Old rule #" << *oldRuleID << ": ";
+      oldRule.dump(out);
+      out << "\nTrying to replay what happened when I simplified this term:\n";
+      Debug |= DebugFlags::Simplify;
+      MutableTerm term = lhs;
+      simplify(lhs);
+
+      dump(out);
+    });
   }
 
   // Tell the caller that we added a new rule.
@@ -339,12 +346,13 @@ void RewriteSystem::addRules(
                                  newRule.getLHS().end(),
                                  newRuleID);
     if (oldRuleID) {
-      llvm::errs() << "Imported rules have duplicate left hand sides!\n";
-      llvm::errs() << "New rule #" << newRuleID << ": " << newRule << "\n";
-      const auto &oldRule = getRule(*oldRuleID);
-      llvm::errs() << "Old rule #" << *oldRuleID << ": " << oldRule << "\n\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Imported rules have duplicate left hand sides!\n";
+        out << "New rule #" << newRuleID << ": " << newRule << "\n";
+        const auto &oldRule = getRule(*oldRuleID);
+        out << "Old rule #" << *oldRuleID << ": " << oldRule << "\n\n";
+        dump(out);
+      });
     }
   }
 
@@ -505,12 +513,13 @@ void RewriteSystem::recordRewriteLoop(MutableTerm basepoint,
 }
 
 void RewriteSystem::verifyRewriteRules(ValidityPolicy policy) const {
-#define ASSERT_RULE(expr) \
-  if (!(expr)) { \
-    llvm::errs() << "&&& Malformed rewrite rule: " << rule << "\n"; \
-    llvm::errs() << "&&& " << #expr << "\n\n"; \
-    dump(llvm::errs()); \
-    abort(); \
+#define ASSERT_RULE(expr)                                                      \
+  if (!(expr)) {                                                               \
+    ABORT([&](auto &out) {                                                     \
+      out << "&&& Malformed rewrite rule: " << rule << "\n";                   \
+      out << "&&& " << #expr << "\n\n";                                        \
+      dump(out);                                                               \
+    });                                                                        \
   }
 
   for (const auto &rule : getLocalRules()) {
diff --git a/lib/AST/RequirementMachine/RewriteSystem.h b/lib/AST/RequirementMachine/RewriteSystem.h
index f1d939ee370e0..7f768270bc2e9 100644
--- a/lib/AST/RequirementMachine/RewriteSystem.h
+++ b/lib/AST/RequirementMachine/RewriteSystem.h
@@ -50,7 +50,13 @@ enum class CompletionResult {
   MaxRuleLength,
 
   /// Maximum concrete type nesting depth exceeded.
-  MaxConcreteNesting
+  MaxConcreteNesting,
+
+  /// Maximum concrete type size exceeded.
+  MaxConcreteSize,
+
+  /// Maximum type difference count exceeded.
+  MaxTypeDifferences,
 };
 
 /// A term rewrite system for working with types in a generic signature.
@@ -107,13 +113,16 @@ class RewriteSystem final {
   /// identities among rewrite rules discovered while resolving critical pairs.
   unsigned RecordLoops : 1;
 
-  /// The length of the longest initial rule, used for the MaxRuleLength
-  /// completion non-termination heuristic.
+  /// The length of the longest initial rule, for the MaxRuleLength limit.
   unsigned LongestInitialRule : 16;
 
-  /// The most deeply nested concrete type appearing in an initial rule, used
-  /// for the MaxConcreteNesting completion non-termination heuristic.
-  unsigned DeepestInitialRule : 16;
+  /// The most deeply nested concrete type appearing in an initial rule,
+  /// for the MaxConcreteNesting limit.
+  unsigned MaxNestingOfInitialRule : 16;
+
+  /// The largest concrete type by total tree node count that appears in an
+  /// initial rule, for the MaxConcreteSize limit.
+  unsigned MaxSizeOfInitialRule : 16;
 
 public:
   explicit RewriteSystem(RewriteContext &ctx);
@@ -143,8 +152,12 @@ class RewriteSystem final {
     return LongestInitialRule;
   }
 
-  unsigned getDeepestInitialRule() const {
-    return DeepestInitialRule;
+  unsigned getMaxNestingOfInitialRule() const {
+    return MaxNestingOfInitialRule;
+  }
+
+  unsigned getMaxSizeOfInitialRule() const {
+    return MaxSizeOfInitialRule;
   }
 
   ArrayRef<const ProtocolDecl *> getProtocols() const {
@@ -206,7 +219,7 @@ class RewriteSystem final {
   //////////////////////////////////////////////////////////////////////////////
 
   /// Pairs of rules which have already been checked for overlap.
-  llvm::DenseSet<std::pair<unsigned, unsigned>> CheckedOverlaps;
+  llvm::DenseSet<std::tuple<unsigned, unsigned, unsigned>> CheckedOverlaps;
 
   std::pair<CompletionResult, unsigned>
   performKnuthBendix(unsigned maxRuleCount, unsigned maxRuleLength);
@@ -311,6 +324,10 @@ class RewriteSystem final {
                              std::optional<unsigned> &lhsDifferenceID,
                              std::optional<unsigned> &rhsDifferenceID);
 
+  unsigned getTypeDifferenceCount() const {
+    return Differences.size();
+  }
+
   const TypeDifference &getTypeDifference(unsigned index) const;
 
   void processTypeDifference(const TypeDifference &difference,
diff --git a/lib/AST/RequirementMachine/Rule.cpp b/lib/AST/RequirementMachine/Rule.cpp
index 4c79b60040d34..b4552ca45c0cf 100644
--- a/lib/AST/RequirementMachine/Rule.cpp
+++ b/lib/AST/RequirementMachine/Rule.cpp
@@ -221,7 +221,12 @@ bool Rule::isDerivedFromConcreteProtocolTypeAliasRule() const {
   return true;
 }
 
-/// Returns the length of the left hand side.
+/// Returns the maximum among the length of the left-hand side,
+/// and the length of any substitution terms that appear in a
+/// property symbol at the end of the left-hand side.
+///
+/// This is a measure of the complexity of the rule, which stops
+/// completion from running forever.
 unsigned Rule::getDepth() const {
   auto result = LHS.size();
 
@@ -234,26 +239,30 @@ unsigned Rule::getDepth() const {
   return result;
 }
 
-/// Returns the nesting depth of the concrete symbol at the end of the
-/// left hand side, or 0 if there isn't one.
-unsigned Rule::getNesting() const {
+/// Returns the complexity of the concrete type in the property symbol
+/// at the end of the left-hand side, if there is one.
+///
+/// This is a measure of the complexity of the rule, which stops
+/// completion from running forever.
+std::pair<unsigned, unsigned>
+Rule::getNestingAndSize() const {
   if (LHS.back().hasSubstitutions()) {
     auto type = LHS.back().getConcreteType();
 
     struct Walker : TypeWalker {
       unsigned Nesting = 0;
       unsigned MaxNesting = 0;
+      unsigned Size = 0;
 
       Action walkToTypePre(Type ty) override {
+        ++Size;
         ++Nesting;
-        MaxNesting = std::max(Nesting, MaxNesting);
-
+        MaxNesting = std::max(MaxNesting, Nesting);
         return Action::Continue;
       }
 
       Action walkToTypePost(Type ty) override {
         --Nesting;
-
         return Action::Continue;
       }
     };
@@ -261,10 +270,10 @@ unsigned Rule::getNesting() const {
     Walker walker;
     type.walk(walker);
 
-    return walker.MaxNesting;
+    return std::make_pair(walker.MaxNesting, walker.Size);
   }
 
-  return 0;
+  return std::make_pair(0, 0);
 }
 
 /// Linear order on rules; compares LHS followed by RHS.
diff --git a/lib/AST/RequirementMachine/Rule.h b/lib/AST/RequirementMachine/Rule.h
index 8519bf1a13ea6..9077741e68fa0 100644
--- a/lib/AST/RequirementMachine/Rule.h
+++ b/lib/AST/RequirementMachine/Rule.h
@@ -224,7 +224,7 @@ class Rule final {
 
   unsigned getDepth() const;
 
-  unsigned getNesting() const;
+  std::pair<unsigned, unsigned> getNestingAndSize() const;
 
   std::optional<int> compare(const Rule &other, RewriteContext &ctx) const;
 
diff --git a/lib/AST/RequirementMachine/RuleBuilder.cpp b/lib/AST/RequirementMachine/RuleBuilder.cpp
index 499480cd0f580..3ba68101fa0c3 100644
--- a/lib/AST/RequirementMachine/RuleBuilder.cpp
+++ b/lib/AST/RequirementMachine/RuleBuilder.cpp
@@ -106,19 +106,10 @@ void RuleBuilder::initWithProtocolSignatureRequirements(
     addPermanentProtocolRules(proto);
 
     auto reqs = proto->getRequirementSignature();
-
-    // If completion failed, we'll have a totally empty requirement signature,
-    // but to maintain invariants around what constitutes a valid rewrite term
-    // between getTypeForTerm() and isValidTypeParameter(), we need to add rules
-    // for inherited protocols.
-    if (reqs.getErrors().contains(GenericSignatureErrorFlags::CompletionFailed)) {
-      for (auto *inheritedProto : proto->getAllInheritedProtocols()) {
-        Requirement req(RequirementKind::Conformance,
-                        proto->getSelfInterfaceType(),
-                        inheritedProto->getDeclaredInterfaceType());
-
-        addRequirement(req.getCanonical(), proto);
-      }
+    auto errors = reqs.getErrors();
+    if (errors.contains(GenericSignatureErrorFlags::CompletionFailed) ||
+        errors.contains(GenericSignatureErrorFlags::CircularReference)) {
+      Failed = 1;
     }
 
     for (auto req : reqs.getRequirements())
@@ -495,6 +486,9 @@ void RuleBuilder::collectRulesFromReferencedProtocols() {
       continue;
     }
 
+    if (machine->isFailed())
+      Failed = 1;
+
     // We grab the machine's local rules, not *all* of its rules, to avoid
     // duplicates in case multiple machines share a dependency on a downstream
     // protocol component.
diff --git a/lib/AST/RequirementMachine/RuleBuilder.h b/lib/AST/RequirementMachine/RuleBuilder.h
index e1ce2e095101c..cc96f36810fb7 100644
--- a/lib/AST/RequirementMachine/RuleBuilder.h
+++ b/lib/AST/RequirementMachine/RuleBuilder.h
@@ -83,11 +83,15 @@ struct RuleBuilder {
   /// Used to ensure the initWith*() methods are only called once.
   unsigned Initialized : 1;
 
+  /// Whether completion failed for any of our upstream protocol components.
+  unsigned Failed : 1;
+
   RuleBuilder(RewriteContext &ctx,
               llvm::DenseSet<const ProtocolDecl *> &referencedProtocols)
       : Context(ctx), ReferencedProtocols(referencedProtocols) {
     Dump = ctx.getASTContext().LangOpts.DumpRequirementMachine;
     Initialized = 0;
+    Failed = 0;
   }
 
   void initWithGenericSignature(ArrayRef<GenericTypeParamType *> genericParams,
diff --git a/lib/AST/RequirementMachine/SimplifySubstitutions.cpp b/lib/AST/RequirementMachine/SimplifySubstitutions.cpp
index 68aeba1277228..b03af4006c80f 100644
--- a/lib/AST/RequirementMachine/SimplifySubstitutions.cpp
+++ b/lib/AST/RequirementMachine/SimplifySubstitutions.cpp
@@ -262,10 +262,11 @@ void RewriteSystem::processTypeDifference(const TypeDifference &difference,
   if (lhsRule.getRHS() == difference.BaseTerm &&
       !lhsRule.isSubstitutionSimplified()) {
     if (lhsRule.isFrozen()) {
-      llvm::errs() << "Frozen rule should already be subst-simplified: "
-                   << lhsRule << "\n\n";
-      dump(llvm::errs());
-      abort();
+      ABORT([&](auto &out) {
+        out << "Frozen rule should already be subst-simplified: " << lhsRule
+            << "\n\n";
+        dump(out);
+      });
     }
     lhsRule.markSubstitutionSimplified();
   }
diff --git a/lib/AST/RequirementMachine/Symbol.cpp b/lib/AST/RequirementMachine/Symbol.cpp
index 47582fcae66c2..d8c3dcaf5cea0 100644
--- a/lib/AST/RequirementMachine/Symbol.cpp
+++ b/lib/AST/RequirementMachine/Symbol.cpp
@@ -366,6 +366,8 @@ Symbol Symbol::forLayout(LayoutConstraint layout,
 /// Creates a superclass symbol, representing a superclass constraint.
 Symbol Symbol::forSuperclass(CanType type, ArrayRef<Term> substitutions,
                              RewriteContext &ctx) {
+  ASSERT(type.getClassOrBoundGenericClass() != nullptr);
+
   llvm::FoldingSetNodeID id;
   id.AddInteger(unsigned(Kind::Superclass));
   id.AddPointer(type.getPointer());
@@ -613,10 +615,11 @@ std::optional<int> Symbol::compare(Symbol other, RewriteContext &ctx) const {
   }
 
   if (result == 0) {
-    llvm::errs() << "Two distinct symbols should not compare equal\n";
-    llvm::errs() << "LHS: " << *this << "\n";
-    llvm::errs() << "RHS: " << other << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Two distinct symbols should not compare equal\n";
+      out << "LHS: " << *this << "\n";
+      out << "RHS: " << other;
+    });
   }
 
   return result;
@@ -646,8 +649,9 @@ Symbol Symbol::withConcreteSubstitutions(
     break;
   }
 
-  llvm::errs() << "Bad symbol kind: " << *this << "\n";
-  abort();
+  ABORT([&](auto &out) {
+    out << "Bad symbol kind: " << *this;
+  });
 }
 
 /// For a superclass or concrete type symbol
diff --git a/lib/AST/RequirementMachine/Term.cpp b/lib/AST/RequirementMachine/Term.cpp
index 90e5b885cb6d3..62cd07e6bd201 100644
--- a/lib/AST/RequirementMachine/Term.cpp
+++ b/lib/AST/RequirementMachine/Term.cpp
@@ -39,13 +39,9 @@ struct Term::Storage final
     return Size;
   }
 
-  MutableArrayRef<Symbol> getElements() {
-    return {getTrailingObjects<Symbol>(), Size};
-  }
+  MutableArrayRef<Symbol> getElements() { return getTrailingObjects(Size); }
 
-  ArrayRef<Symbol> getElements() const {
-    return {getTrailingObjects<Symbol>(), Size};
-  }
+  ArrayRef<Symbol> getElements() const { return getTrailingObjects(Size); }
 
   void Profile(llvm::FoldingSetNodeID &id) const;
 };
@@ -122,19 +118,42 @@ bool Term::containsNameSymbols() const {
   return false;
 }
 
-/// Shortlex order on symbol ranges.
+/// Weighted shortlex order on symbol ranges, used for implementing
+/// Term::compare() and MutableTerm::compare().
+///
+/// We first compute a weight vector for both terms and compare the
+/// vectors lexicographically:
+/// - Weight of generic param symbols
+/// - Number of name symbols
+/// - Number of element symbols
 ///
-/// First we compare length, then perform a lexicographic comparison
-/// on symbols if the two ranges have the same length.
+/// If the terms have the same weight, we compare length.
 ///
-/// This is used to implement Term::compare() and MutableTerm::compare()
-/// below.
-static std::optional<int> shortlexCompare(const Symbol *lhsBegin,
-                                          const Symbol *lhsEnd,
-                                          const Symbol *rhsBegin,
-                                          const Symbol *rhsEnd,
-                                          RewriteContext &ctx) {
-  // First, compare the number of name and pack element symbols.
+/// If the terms have the same weight and length, we perform a
+/// lexicographic comparison on symbols.
+///
+static std::optional<int> compareImpl(const Symbol *lhsBegin,
+                                      const Symbol *lhsEnd,
+                                      const Symbol *rhsBegin,
+                                      const Symbol *rhsEnd,
+                                      RewriteContext &ctx) {
+  ASSERT(lhsBegin != lhsEnd);
+  ASSERT(rhsBegin != rhsEnd);
+
+  // First compare weights on generic parameters. The implicit
+  // assumption here is we don't form terms with generic parameter
+  // symbols in the middle, which is true. Otherwise, we'd need
+  // to add up their weights like we do below for name symbols,
+  // of course.
+  if (lhsBegin->getKind() == Symbol::Kind::GenericParam &&
+      rhsBegin->getKind() == Symbol::Kind::GenericParam) {
+    unsigned lhsWeight = lhsBegin->getGenericParam()->getWeight();
+    unsigned rhsWeight = rhsBegin->getGenericParam()->getWeight();
+    if (lhsWeight != rhsWeight)
+      return lhsWeight > rhsWeight ? 1 : -1;
+  }
+
+  // Compare the number of name and pack element symbols.
   unsigned lhsNameCount = 0;
   unsigned lhsPackElementCount = 0;
   for (auto *iter = lhsBegin; iter != lhsEnd; ++iter) {
@@ -192,17 +211,17 @@ static std::optional<int> shortlexCompare(const Symbol *lhsBegin,
   return 0;
 }
 
-/// Shortlex order on terms. Returns None if the terms are identical except
+/// Reduction order on terms. Returns None if the terms are identical except
 /// for an incomparable superclass or concrete type symbol at the end.
 std::optional<int> Term::compare(Term other, RewriteContext &ctx) const {
-  return shortlexCompare(begin(), end(), other.begin(), other.end(), ctx);
+  return compareImpl(begin(), end(), other.begin(), other.end(), ctx);
 }
 
-/// Shortlex order on mutable terms. Returns None if the terms are identical
+/// Reduction order on mutable terms. Returns None if the terms are identical
 /// except for an incomparable superclass or concrete type symbol at the end.
 std::optional<int> MutableTerm::compare(const MutableTerm &other,
                                         RewriteContext &ctx) const {
-  return shortlexCompare(begin(), end(), other.begin(), other.end(), ctx);
+  return compareImpl(begin(), end(), other.begin(), other.end(), ctx);
 }
 
 /// Replace the subterm in the range [from,to) of this term with \p rhs.
diff --git a/lib/AST/RequirementMachine/TypeDifference.cpp b/lib/AST/RequirementMachine/TypeDifference.cpp
index a575882659dca..e1b18ef8344c2 100644
--- a/lib/AST/RequirementMachine/TypeDifference.cpp
+++ b/lib/AST/RequirementMachine/TypeDifference.cpp
@@ -63,9 +63,9 @@ MutableTerm TypeDifference::getReplacementSubstitution(unsigned index) const {
 }
 
 void TypeDifference::dump(llvm::raw_ostream &out) const {
-  llvm::errs() << "Base term: " << BaseTerm << "\n";
-  llvm::errs() << "LHS: " << LHS << "\n";
-  llvm::errs() << "RHS: " << RHS << "\n";
+  out << "Base term: " << BaseTerm << "\n";
+  out << "LHS: " << LHS << "\n";
+  out << "RHS: " << RHS << "\n";
 
   for (const auto &pair : SameTypes) {
     out << "- " << getOriginalSubstitution(pair.first) << " (#";
@@ -79,11 +79,12 @@ void TypeDifference::dump(llvm::raw_ostream &out) const {
 }
 
 void TypeDifference::verify(RewriteContext &ctx) const {
-#define VERIFY(expr, str) \
-  if (!(expr)) { \
-    llvm::errs() << "TypeDifference::verify(): " << str << "\n"; \
-    dump(llvm::errs()); \
-    abort(); \
+#define VERIFY(expr, str)                                                      \
+  if (!(expr)) {                                                               \
+    ABORT([&](auto &out) {                                                     \
+      out << "TypeDifference::verify(): " << str << "\n";                      \
+      dump(out);                                                               \
+    });                                                                        \
   }
 
   VERIFY(LHS.getKind() == RHS.getKind(), "Kind mismatch");
@@ -214,12 +215,13 @@ namespace {
     }
 
     void verify() const {
-#define VERIFY(expr, str) \
-  if (!(expr)) { \
-    llvm::errs() << "ConcreteTypeMatcher::verify(): " << str << "\n"; \
-    dump(llvm::errs()); \
-    abort(); \
-  }
+#define VERIFY(expr, str)                                                      \
+    if (!(expr)) {                                                             \
+      ABORT([&](auto &out) {                                                   \
+        out << "ConcreteTypeMatcher::verify(): " << str << "\n";               \
+        dump(out);                                                             \
+      });                                                                      \
+    }
 
       llvm::DenseSet<unsigned> lhsVisited;
       llvm::DenseSet<unsigned> rhsVisited;
@@ -460,16 +462,17 @@ bool RewriteSystem::computeTypeDifference(
   if (!isConflict) {
     // The meet operation should be commutative.
     if (lhsMeetRhs.RHS != rhsMeetLhs.RHS) {
-      llvm::errs() << "Meet operation was not commutative:\n\n";
+      ABORT([&](auto &out) {
+        out << "Meet operation was not commutative:\n\n";
 
-      llvm::errs() << "LHS: " << lhs << "\n";
-      llvm::errs() << "RHS: " << rhs << "\n";
-      matcher.dump(llvm::errs());
+        out << "LHS: " << lhs << "\n";
+        out << "RHS: " << rhs << "\n";
+        matcher.dump(out);
 
-      llvm::errs() << "\n";
-      llvm::errs() << "LHS ∧ RHS: " << lhsMeetRhs.RHS << "\n";
-      llvm::errs() << "RHS ∧ LHS: " << rhsMeetLhs.RHS << "\n";
-      abort();
+        out << "\n";
+        out << "LHS ∧ RHS: " << lhsMeetRhs.RHS << "\n";
+        out << "RHS ∧ LHS: " << rhsMeetLhs.RHS;
+      });
     }
 
     // The meet operation should be idempotent.
@@ -483,16 +486,17 @@ bool RewriteSystem::computeTypeDifference(
       lhsMeetLhsMeetRhs.verify(Context);
 
       if (lhsMeetRhs.RHS != lhsMeetLhsMeetRhs.RHS) {
-        llvm::errs() << "Meet operation was not idempotent:\n\n";
+        ABORT([&](auto &out) {
+          out << "Meet operation was not idempotent:\n\n";
 
-        llvm::errs() << "LHS: " << lhs << "\n";
-        llvm::errs() << "RHS: " << rhs << "\n";
-        matcher.dump(llvm::errs());
+          out << "LHS: " << lhs << "\n";
+          out << "RHS: " << rhs << "\n";
+          matcher.dump(out);
 
-        llvm::errs() << "\n";
-        llvm::errs() << "LHS ∧ RHS: " << lhsMeetRhs.RHS << "\n";
-        llvm::errs() << "LHS ∧ (LHS ∧ RHS): " << lhsMeetLhsMeetRhs.RHS << "\n";
-        abort();
+          out << "\n";
+          out << "LHS ∧ RHS: " << lhsMeetRhs.RHS << "\n";
+          out << "LHS ∧ (LHS ∧ RHS): " << lhsMeetLhsMeetRhs.RHS;
+        });
       }
     }
 
@@ -506,16 +510,17 @@ bool RewriteSystem::computeTypeDifference(
       rhsMeetRhsMeetRhs.verify(Context);
 
       if (lhsMeetRhs.RHS != rhsMeetRhsMeetRhs.RHS) {
-        llvm::errs() << "Meet operation was not idempotent:\n\n";
+        ABORT([&](auto &out) {
+          out << "Meet operation was not idempotent:\n\n";
 
-        llvm::errs() << "LHS: " << lhs << "\n";
-        llvm::errs() << "RHS: " << rhs << "\n";
-        matcher.dump(llvm::errs());
+          out << "LHS: " << lhs << "\n";
+          out << "RHS: " << rhs << "\n";
+          matcher.dump(out);
 
-        llvm::errs() << "\n";
-        llvm::errs() << "RHS ∧ LHS: " << rhsMeetLhs.RHS << "\n";
-        llvm::errs() << "RHS ∧ (RHS ∧ LHS): " << rhsMeetRhsMeetRhs.RHS << "\n";
-        abort();
+          out << "\n";
+          out << "RHS ∧ LHS: " << rhsMeetLhs.RHS << "\n";
+          out << "RHS ∧ (RHS ∧ LHS): " << rhsMeetRhsMeetRhs.RHS;
+        });
       }
     }
   }
diff --git a/lib/AST/SILLayout.cpp b/lib/AST/SILLayout.cpp
index 2a4599b7baf6d..efcf5ac734934 100644
--- a/lib/AST/SILLayout.cpp
+++ b/lib/AST/SILLayout.cpp
@@ -82,7 +82,7 @@ SILLayout::SILLayout(CanGenericSignature Sig,
 #ifndef NDEBUG
   verifyFields(Sig, Fields);
 #endif
-  auto FieldsMem = getTrailingObjects<SILField>();
+  auto *FieldsMem = getTrailingObjects();
   for (unsigned i : indices(Fields)) {
     new (FieldsMem + i) SILField(Fields[i]);
   }
diff --git a/lib/AST/SearchPathOptions.cpp b/lib/AST/SearchPathOptions.cpp
index 23bb767a5bdf2..308c0fc4754a0 100644
--- a/lib/AST/SearchPathOptions.cpp
+++ b/lib/AST/SearchPathOptions.cpp
@@ -58,14 +58,10 @@ void ModuleSearchPathLookup::rebuildLookupTable(const SearchPathOptions *Opts,
                                 Entry.value().IsSystem, Entry.index());
   }
 
-  // Apple platforms have extra implicit framework search paths:
-  // $SDKROOT/System/Library/Frameworks/ and $SDKROOT/Library/Frameworks/.
-  if (IsOSDarwin) {
-    for (auto Entry : llvm::enumerate(Opts->getDarwinImplicitFrameworkSearchPaths())) {
-      addFilesInPathToLookupTable(FS, Entry.value(),
-                                  ModuleSearchPathKind::DarwinImplicitFramework,
-                                  /*isSystem=*/true, Entry.index());
-    }
+  for (auto Entry : llvm::enumerate(Opts->getImplicitFrameworkSearchPaths())) {
+    addFilesInPathToLookupTable(FS, Entry.value(),
+                                ModuleSearchPathKind::ImplicitFramework,
+                                /*isSystem=*/true, Entry.index());
   }
 
   for (auto Entry : llvm::enumerate(Opts->getRuntimeLibraryImportPaths())) {
@@ -123,12 +119,9 @@ void SearchPathOptions::dump(bool isDarwin) const {
                  << Entry.value().Path << "\n";
   }
 
-  if (isDarwin) {
-    llvm::errs() << "Darwin implicit framework search paths:\n";
-    for (auto Entry :
-         llvm::enumerate(getDarwinImplicitFrameworkSearchPaths())) {
-      llvm::errs() << "  [" << Entry.index() << "] " << Entry.value() << "\n";
-    }
+  llvm::errs() << "Implicit framework search paths:\n";
+  for (auto Entry : llvm::enumerate(getImplicitFrameworkSearchPaths())) {
+    llvm::errs() << "  [" << Entry.index() << "] " << Entry.value() << "\n";
   }
 
   llvm::errs() << "Runtime library import search paths:\n";
diff --git a/lib/AST/Stmt.cpp b/lib/AST/Stmt.cpp
index 273ab7b9ca8cf..95529d2af8216 100644
--- a/lib/AST/Stmt.cpp
+++ b/lib/AST/Stmt.cpp
@@ -184,8 +184,7 @@ BraceStmt::BraceStmt(SourceLoc lbloc, ArrayRef<ASTNode> elts, SourceLoc rbloc,
     : Stmt(StmtKind::Brace, getDefaultImplicitFlag(implicit, lbloc)),
       LBLoc(lbloc), RBLoc(rbloc) {
   Bits.BraceStmt.NumElements = elts.size();
-  std::uninitialized_copy(elts.begin(), elts.end(),
-                          getTrailingObjects<ASTNode>());
+  std::uninitialized_copy(elts.begin(), elts.end(), getTrailingObjects());
 
 #ifndef NDEBUG
   for (auto elt : elts)
@@ -302,6 +301,11 @@ ASTNode BraceStmt::findAsyncNode() {
   return asyncFinder.getAsyncNode();
 }
 
+bool BraceStmt::hasExplicitReturnStmt(ASTContext &ctx) const {
+  return evaluateOrDefault(ctx.evaluator,
+                           BraceHasExplicitReturnStmtRequest{this}, false);
+}
+
 static bool hasSingleActiveElement(ArrayRef<ASTNode> elts) {
   return elts.size() == 1;
 }
@@ -493,7 +497,7 @@ Type DoCatchStmt::getCaughtErrorType() const {
     ->getCaseLabelItems()
     .front()
     .getPattern();
-  if (firstPattern->hasType())
+  if (firstPattern->hasType() && !firstPattern->getType()->hasError())
     return firstPattern->getType();
 
   return Type();
@@ -514,8 +518,6 @@ void LabeledConditionalStmt::setCond(StmtCondition e) {
 /// or `let self = self` condition.
 ///  - If `requiresCaptureListRef` is `true`, additionally requires that the
 ///    RHS of the self condition references a var defined in a capture list.
-///  - If `requireLoadExpr` is `true`, additionally requires that the RHS of
-///    the self condition is a `LoadExpr`.
 bool LabeledConditionalStmt::rebindsSelf(ASTContext &Ctx,
                                          bool requiresCaptureListRef,
                                          bool requireLoadExpr) const {
@@ -529,8 +531,6 @@ bool LabeledConditionalStmt::rebindsSelf(ASTContext &Ctx,
 /// or `let self = self` condition.
 ///  - If `requiresCaptureListRef` is `true`, additionally requires that the
 ///    RHS of the self condition references a var defined in a capture list.
-///  - If `requireLoadExpr` is `true`, additionally requires that the RHS of
-///    the self condition is a `LoadExpr`.
 bool StmtConditionElement::rebindsSelf(ASTContext &Ctx,
                                        bool requiresCaptureListRef,
                                        bool requireLoadExpr) const {
@@ -756,16 +756,17 @@ SourceLoc CaseLabelItem::getEndLoc() const {
 CaseStmt::CaseStmt(CaseParentKind parentKind, SourceLoc itemIntroducerLoc,
                    ArrayRef<CaseLabelItem> caseLabelItems,
                    SourceLoc unknownAttrLoc, SourceLoc itemTerminatorLoc,
-                   BraceStmt *body,
-                   std::optional<MutableArrayRef<VarDecl *>> caseBodyVariables,
+                   BraceStmt *body, ArrayRef<VarDecl *> caseBodyVariables,
                    std::optional<bool> implicit,
                    NullablePtr<FallthroughStmt> fallthroughStmt)
     : Stmt(StmtKind::Case, getDefaultImplicitFlag(implicit, itemIntroducerLoc)),
       UnknownAttrLoc(unknownAttrLoc), ItemIntroducerLoc(itemIntroducerLoc),
       ItemTerminatorLoc(itemTerminatorLoc), ParentKind(parentKind),
-      BodyAndHasFallthrough(body, fallthroughStmt.isNonNull()),
-      CaseBodyVariables(caseBodyVariables) {
+      BodyAndHasFallthrough(body, fallthroughStmt.isNonNull()) {
   Bits.CaseStmt.NumPatterns = caseLabelItems.size();
+  Bits.CaseStmt.NumCaseBodyVars = caseBodyVariables.size();
+  ASSERT(Bits.CaseStmt.NumCaseBodyVars == caseBodyVariables.size() &&
+         "too many case body vars");
   assert(Bits.CaseStmt.NumPatterns > 0 &&
          "case block must have at least one pattern");
   assert(
@@ -775,36 +776,66 @@ CaseStmt::CaseStmt(CaseParentKind parentKind, SourceLoc itemIntroducerLoc,
     *getTrailingObjects<FallthroughStmt *>() = fallthroughStmt.get();
   }
 
+  std::uninitialized_copy(caseBodyVariables.begin(), caseBodyVariables.end(),
+                          getCaseBodyVariablesBuffer().begin());
+
   MutableArrayRef<CaseLabelItem> items{getTrailingObjects<CaseLabelItem>(),
                                        static_cast<size_t>(Bits.CaseStmt.NumPatterns)};
 
-  // At the beginning mark all of our var decls as being owned by this
-  // statement. In the typechecker we wireup the case stmt var decl list since
-  // we know everything is lined up/typechecked then.
   for (unsigned i : range(Bits.CaseStmt.NumPatterns)) {
     new (&items[i]) CaseLabelItem(caseLabelItems[i]);
-    items[i].getPattern()->markOwnedByStatement(this);
-  }
-  for (auto *vd : caseBodyVariables.value_or(MutableArrayRef<VarDecl *>())) {
-    vd->setParentPatternStmt(this);
+    // Mark the CaseStmt as the parent for any canonical VarDecls in the
+    // pattern.
+    items[i].getPattern()->forEachVariable([&](VarDecl *VD) {
+      if (!VD->getParentVarDecl())
+        VD->setParentPatternStmt(this);
+    });
   }
 }
 
 namespace {
-static MutableArrayRef<VarDecl *>
-getCaseVarDecls(ASTContext &ctx, ArrayRef<CaseLabelItem> labelItems) {
-  // Grab the first case label item pattern and use it to initialize the case
-  // body var decls.
-  SmallVector<VarDecl *, 4> tmp;
-  labelItems.front().getPattern()->collectVariables(tmp);
-  return ctx.AllocateTransform<VarDecl *>(
-      llvm::ArrayRef(tmp), [&](VarDecl *vOld) -> VarDecl * {
-        auto *vNew = new (ctx) VarDecl(
-            /*IsStatic*/ false, vOld->getIntroducer(), vOld->getNameLoc(),
-            vOld->getName(), vOld->getDeclContext());
-        vNew->setImplicit();
-        return vNew;
-      });
+/// Produces an array of internal case body variables, and binds all of the
+/// pattern variables that occur within the case to their "parent" pattern
+/// variables, forming chains of variables with the same name.
+///
+/// Given a case such as:
+/// \code
+/// case .a(let x), .b(let x), .c(let x):
+/// \endcode
+///
+/// Each case item contains a (different) pattern variable named `x`. This
+/// function will set the "parent" variable of the second and third `x`
+/// variables to the `x` variable immediately to its left. A fourth `x` will be
+/// the body case variable, whose parent will be set to the `x` within the final
+/// case item.
+static void getCaseVarDecls(ASTContext &ctx, ArrayRef<CaseLabelItem> labelItems,
+                            SmallVectorImpl<VarDecl *> &caseVars) {
+  llvm::SmallDenseMap<Identifier, VarDecl *, 4> allVars;
+
+  auto foundVar = [&](VarDecl *VD) {
+    if (!VD->hasName())
+      return;
+
+    auto &entry = allVars[VD->getName()];
+    if (entry) {
+      VD->setParentVarDecl(entry);
+    } else {
+      auto *caseVar = new (ctx) VarDecl(
+          /*IsStatic*/ false, VD->getIntroducer(), VD->getNameLoc(),
+          VD->getName(), VD->getDeclContext());
+      caseVar->setImplicit();
+      caseVars.push_back(caseVar);
+    }
+    entry = VD;
+  };
+
+  for (auto &caseItem : labelItems)
+    caseItem.getPattern()->forEachVariable(foundVar);
+
+  // Now that we've collected the case variables, ensure they're parented to
+  // the last pattern variables we saw.
+  for (auto caseVar : caseVars)
+    foundVar(caseVar);
 }
 
 struct FallthroughFinder : ASTWalker {
@@ -855,7 +886,8 @@ CaseStmt::createParsedSwitchCase(ASTContext &ctx, SourceLoc introducerLoc,
                                  ArrayRef<CaseLabelItem> caseLabelItems,
                                  SourceLoc unknownAttrLoc, SourceLoc colonLoc,
                                  BraceStmt *body) {
-  auto caseVarDecls = getCaseVarDecls(ctx, caseLabelItems);
+  SmallVector<VarDecl *, 4> caseVarDecls;
+  getCaseVarDecls(ctx, caseLabelItems, caseVarDecls);
   auto fallthroughStmt = FallthroughFinder().findFallthrough(body);
   return create(ctx, CaseParentKind::Switch, introducerLoc, caseLabelItems,
                 unknownAttrLoc, colonLoc, body, caseVarDecls,
@@ -865,23 +897,37 @@ CaseStmt::createParsedSwitchCase(ASTContext &ctx, SourceLoc introducerLoc,
 CaseStmt *CaseStmt::createParsedDoCatch(ASTContext &ctx, SourceLoc catchLoc,
                                         ArrayRef<CaseLabelItem> caseLabelItems,
                                         BraceStmt *body) {
-  auto caseVarDecls = getCaseVarDecls(ctx, caseLabelItems);
+  SmallVector<VarDecl *, 4> caseVarDecls;
+  getCaseVarDecls(ctx, caseLabelItems, caseVarDecls);
   return create(ctx, CaseParentKind::DoCatch, catchLoc, caseLabelItems,
                 /*unknownAttrLoc=*/SourceLoc(), body->getStartLoc(), body,
                 caseVarDecls, /*implicit=*/false, /*fallthroughStmt=*/nullptr);
 }
 
 CaseStmt *
-CaseStmt::create(ASTContext &ctx, CaseParentKind ParentKind, SourceLoc caseLoc,
-                 ArrayRef<CaseLabelItem> caseLabelItems,
-                 SourceLoc unknownAttrLoc, SourceLoc colonLoc, BraceStmt *body,
-                 std::optional<MutableArrayRef<VarDecl *>> caseVarDecls,
-                 std::optional<bool> implicit,
-                 NullablePtr<FallthroughStmt> fallthroughStmt) {
-  void *mem =
-      ctx.Allocate(totalSizeToAlloc<FallthroughStmt *, CaseLabelItem>(
-                       fallthroughStmt.isNonNull(), caseLabelItems.size()),
-                   alignof(CaseStmt));
+CaseStmt::createImplicit(ASTContext &ctx, CaseParentKind parentKind,
+                         ArrayRef<CaseLabelItem> caseLabelItems,
+                         BraceStmt *body,
+                         NullablePtr<FallthroughStmt> fallthroughStmt) {
+  SmallVector<VarDecl *, 4> caseVarDecls;
+  getCaseVarDecls(ctx, caseLabelItems, caseVarDecls);
+  return create(ctx, parentKind, /*catchLoc*/ SourceLoc(), caseLabelItems,
+                /*unknownAttrLoc*/ SourceLoc(), /*colonLoc*/ SourceLoc(), body,
+                caseVarDecls, /*implicit*/ true, fallthroughStmt);
+}
+
+CaseStmt *CaseStmt::create(ASTContext &ctx, CaseParentKind ParentKind,
+                           SourceLoc caseLoc,
+                           ArrayRef<CaseLabelItem> caseLabelItems,
+                           SourceLoc unknownAttrLoc, SourceLoc colonLoc,
+                           BraceStmt *body, ArrayRef<VarDecl *> caseVarDecls,
+                           std::optional<bool> implicit,
+                           NullablePtr<FallthroughStmt> fallthroughStmt) {
+  void *mem = ctx.Allocate(
+      totalSizeToAlloc<FallthroughStmt *, CaseLabelItem, VarDecl *>(
+          fallthroughStmt.isNonNull(), caseLabelItems.size(),
+          caseVarDecls.size()),
+      alignof(CaseStmt));
   return ::new (mem)
       CaseStmt(ParentKind, caseLoc, caseLabelItems, unknownAttrLoc, colonLoc,
                body, caseVarDecls, implicit, fallthroughStmt);
@@ -951,7 +997,7 @@ SwitchStmt *SwitchStmt::create(LabeledStmtInfo LabelInfo, SourceLoc SwitchLoc,
                                                EndLoc);
 
   std::uninitialized_copy(Cases.begin(), Cases.end(),
-                          theSwitch->getTrailingObjects<CaseStmt *>());
+                          theSwitch->getTrailingObjects());
   for (auto *caseStmt : theSwitch->getCases())
     caseStmt->setParentStmt(theSwitch);
 
diff --git a/lib/AST/SubstitutionMap.cpp b/lib/AST/SubstitutionMap.cpp
index eb2410760426a..772f2976ea358 100644
--- a/lib/AST/SubstitutionMap.cpp
+++ b/lib/AST/SubstitutionMap.cpp
@@ -174,14 +174,12 @@ SubstitutionMap SubstitutionMap::get(GenericSignature genericSig,
   // Form the stored conformances.
   SmallVector<ProtocolConformanceRef, 4> conformances;
   for (const auto &req : genericSig.getRequirements()) {
-    if (req.getKind() != RequirementKind::Conformance) continue;
-
-    CanType depTy = req.getFirstType()->getCanonicalType();
-    auto replacement = depTy.subst(IFS);
-    auto *proto = req.getProtocolDecl();
-    auto conformance = IFS.lookupConformance(depTy, replacement, proto,
-                                             /*level=*/0);
-    conformances.push_back(conformance);
+    if (req.getKind() != RequirementKind::Conformance)
+      continue;
+
+    conformances.push_back(
+      IFS.lookupConformance(
+        req.getFirstType(), req.getProtocolDecl(), /*level=*/0));
   }
 
   return SubstitutionMap(genericSig, types, conformances);
@@ -269,66 +267,24 @@ SubstitutionMap::lookupConformance(CanType type, ProtocolDecl *proto) const {
 
   // If the protocol is invertible, fall back to a global lookup instead of
   // evaluating a conformance path, to avoid an infinite substitution issue.
+  //
+  // FIXME: Figure out a more principled way of breaking this cycle.
   if (proto->getInvertibleProtocolKind())
     return swift::lookupConformance(type.subst(*this), proto);
 
   auto path = genericSig->getConformancePath(type, proto);
 
-  ProtocolConformanceRef conformance;
-  for (const auto &step : path) {
-    // For the first step, grab the initial conformance.
-    if (conformance.isInvalid()) {
-      if (auto initialConformance = getSignatureConformance(
-            step.first, step.second)) {
-        conformance = *initialConformance;
-        continue;
-      }
-
-      // We couldn't find the initial conformance, fail.
-      return ProtocolConformanceRef::forInvalid();
-    }
+  // For the first step, grab the initial conformance.
+  auto iter = path.begin();
+  const auto step = *iter++;
 
-    // If we've hit an abstract conformance, everything from here on out is
-    // abstract.
-    // FIXME: This may not always be true, but it holds for now.
-    if (conformance.isAbstract()) {
-      // FIXME: Rip this out once we can get a concrete conformance from
-      // an archetype.
-      return swift::lookupConformance(type.subst(*this), proto);
-    }
+  ProtocolConformanceRef conformance =
+      *getSignatureConformance(step.first, step.second);
 
-    // For the second step, we're looking into the requirement signature for
-    // this protocol.
-    if (conformance.isPack()) {
-      auto pack = conformance.getPack();
-      conformance = ProtocolConformanceRef(
-          pack->getAssociatedConformance(step.first, step.second));
-      if (conformance.isInvalid())
-        return conformance;
-
-      continue;
-    }
-
-    auto concrete = conformance.getConcrete();
-    auto normal = concrete->getRootNormalConformance();
-
-    // If we haven't set the signature conformances yet, force the issue now.
-    if (!normal->hasComputedAssociatedConformances()) {
-      // If we're in the process of checking the type witnesses, fail
-      // gracefully.
-      //
-      // FIXME: This is unsound, because we may not have diagnosed anything but
-      // still end up with an ErrorType in the AST.
-      if (proto->getASTContext().evaluator.hasActiveRequest(
-            ResolveTypeWitnessesRequest{normal})) {
-        return ProtocolConformanceRef::forInvalid();
-      }
-    }
-
-    // Get the associated conformance.
-    conformance = concrete->getAssociatedConformance(step.first, step.second);
-    if (conformance.isInvalid())
-      return conformance;
+  // For each remaining step, project an associated conformance.
+  while (iter != path.end()) {
+    const auto step = *iter++;
+    conformance = conformance.getAssociatedConformance(step.first, step.second);
   }
 
   return conformance;
@@ -336,7 +292,7 @@ SubstitutionMap::lookupConformance(CanType type, ProtocolDecl *proto) const {
 
 SubstitutionMap SubstitutionMap::mapReplacementTypesOutOfContext() const {
   return subst(MapTypeOutOfContext(),
-               MakeAbstractConformanceForGenericType(),
+               LookUpConformanceInModule(),
                SubstFlags::PreservePackExpansionLevel |
                SubstFlags::SubstitutePrimaryArchetypes);
 }
@@ -357,6 +313,13 @@ SubstitutionMap SubstitutionMap::subst(TypeSubstitutionFn subs,
 SubstitutionMap SubstitutionMap::subst(InFlightSubstitution &IFS) const {
   if (empty()) return SubstitutionMap();
 
+  // FIXME: Get this caching working with pack expansions as well.
+  if (IFS.ActivePackExpansions.empty()) {
+    auto found = IFS.SubMaps.find(*this);
+    if (found != IFS.SubMaps.end())
+      return found->second;
+  }
+
   SmallVector<Type, 4> newSubs;
   for (Type type : getReplacementTypes()) {
     newSubs.push_back(type.subst(IFS));
@@ -369,28 +332,27 @@ SubstitutionMap SubstitutionMap::subst(InFlightSubstitution &IFS) const {
 
   auto genericSig = getGenericSignature();
   for (const auto &req : genericSig.getRequirements()) {
-    if (req.getKind() != RequirementKind::Conformance) continue;
-
-    auto conformance = oldConformances[0];
-
-    // Fast path for concrete case -- we don't need to compute substType
-    // at all.
-    if (conformance.isConcrete() &&
-        !IFS.shouldSubstituteOpaqueArchetypes()) {
-      newConformances.push_back(
-        ProtocolConformanceRef(conformance.getConcrete()->subst(IFS)));
-    } else {
-      auto origType = req.getFirstType();
-      auto substType = origType.subst(*this);
+    if (req.getKind() != RequirementKind::Conformance)
+      continue;
 
-      newConformances.push_back(conformance.subst(substType, IFS));
-    }
-    
+    newConformances.push_back(oldConformances[0].subst(IFS));
     oldConformances = oldConformances.slice(1);
   }
 
   assert(oldConformances.empty());
-  return SubstitutionMap(genericSig, newSubs, newConformances);
+  auto result = SubstitutionMap(genericSig, newSubs, newConformances);
+
+  if (IFS.ActivePackExpansions.empty())
+    (void) IFS.SubMaps.insert(std::make_pair(*this, result));
+
+  return result;
+}
+
+SubstitutionMap
+SubstitutionMap::getProtocolSubstitutions(ProtocolConformanceRef conformance) {
+  return getProtocolSubstitutions(conformance.getProtocol(),
+                                  conformance.getType(),
+                                  conformance);
 }
 
 SubstitutionMap
@@ -433,8 +395,7 @@ OverrideSubsInfo::OverrideSubsInfo(const NominalTypeDecl *baseNominal,
                                    const NominalTypeDecl *derivedNominal,
                                    GenericSignature baseSig,
                                    const GenericParamList *derivedParams)
-  : Ctx(baseSig->getASTContext()),
-    BaseDepth(0),
+  : BaseDepth(0),
     OrigDepth(0),
     DerivedParams(derivedParams) {
 
@@ -474,10 +435,7 @@ Type QueryOverrideSubs::operator()(SubstitutableType *type) const {
             ->getDeclaredInterfaceType();
       }
 
-      return GenericTypeParamType::get(
-          gp->getParamKind(),
-          gp->getDepth() + info.OrigDepth - info.BaseDepth,
-          gp->getIndex(), gp->getValueType(), info.Ctx);
+      return gp->withDepth(gp->getDepth() + info.OrigDepth - info.BaseDepth);
     }
   }
 
@@ -485,16 +443,18 @@ Type QueryOverrideSubs::operator()(SubstitutableType *type) const {
 }
 
 ProtocolConformanceRef
-LookUpConformanceInOverrideSubs::operator()(CanType type,
-                                            Type substType,
+LookUpConformanceInOverrideSubs::operator()(InFlightSubstitution &IFS,
+                                            Type type,
                                             ProtocolDecl *proto) const {
   if (type->getRootGenericParam()->getDepth() >= info.BaseDepth)
-    return ProtocolConformanceRef::forAbstract(substType, proto);
+    return ProtocolConformanceRef::forAbstract(type.subst(IFS), proto);
 
-  if (auto conformance = info.BaseSubMap.lookupConformance(type, proto))
+  if (auto conformance = info.BaseSubMap.lookupConformance(
+        type->getCanonicalType(), proto)) {
     return conformance;
+  }
 
-  return lookupConformance(substType, proto);
+  return lookupConformance(type.subst(IFS), proto);
 }
 
 SubstitutionMap
@@ -545,10 +505,10 @@ void SubstitutionMap::verify(bool allowInvalid) const {
 
     if (conformance.isInvalid()) {
       if (!allowInvalid) {
-        llvm::errs() << "Unexpected invalid conformance in substitution map:\n";
-        dump(llvm::dbgs());
-        llvm::errs() << "\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Unexpected invalid conformance in substitution map:\n";
+          dump(out);
+        });
       }
 
       continue;
@@ -559,13 +519,12 @@ void SubstitutionMap::verify(bool allowInvalid) const {
           !substType->is<PackElementType>() &&
           !substType->is<ArchetypeType>() &&
           !substType->isTypeVariableOrMember() &&
-          !substType->is<UnresolvedType>() &&
           !substType->is<PlaceholderType>() &&
           !substType->is<ErrorType>()) {
-        llvm::errs() << "Unexpected abstract conformance in substitution map:\n";
-        dump(llvm::errs());
-        llvm::errs() << "\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Unexpected abstract conformance in substitution map:\n";
+          dump(out);
+        });
       }
 
       continue;
@@ -590,12 +549,12 @@ void SubstitutionMap::verify(bool allowInvalid) const {
         if (substType->getSuperclass())
           continue;
 
-        llvm::errs() << "Expected to find a self conformance:\n";
-        substType->dump(llvm::errs());
-        llvm::errs() << "Substitution map:\n";
-        dump(llvm::errs());
-        llvm::errs() << "\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Expected to find a self conformance:\n";
+          substType->dump(out);
+          out << "Substitution map:\n";
+          dump(out);
+        });
       }
 
       continue;
@@ -605,14 +564,14 @@ void SubstitutionMap::verify(bool allowInvalid) const {
       continue;
 
     if (!concrete->getType()->isEqual(substType)) {
-      llvm::errs() << "Conformance with wrong conforming type:\n";
-      concrete->getType()->dump(llvm::errs());
-      llvm::errs() << "Should be:\n";
-      substType->dump(llvm::errs());
-      llvm::errs() << "Substitution map:\n";
-      dump(llvm::errs());
-      llvm::errs() << "\n";
-      abort();
+      ABORT([&](auto &out) {
+        out << "Conformance with wrong conforming type:\n";
+        concrete->getType()->dump(out);
+        out << "Should be:\n";
+        substType->dump(out);
+        out << "Substitution map:\n";
+        dump(out);
+      });
     }
   }
 }
@@ -659,45 +618,60 @@ bool SubstitutionMap::isIdentity() const {
   return !hasNonIdentityReplacement;
 }
 
-SubstitutionMap SubstitutionMap::mapIntoTypeExpansionContext(
-    TypeExpansionContext context) const {
+SubstitutionMap swift::substOpaqueTypesWithUnderlyingTypes(
+    SubstitutionMap subs, TypeExpansionContext context) {
   ReplaceOpaqueTypesWithUnderlyingTypes replacer(
       context.getContext(), context.getResilienceExpansion(),
       context.isWholeModuleContext());
-  return this->subst(replacer, replacer,
-                     SubstFlags::SubstituteOpaqueArchetypes |
-                     SubstFlags::PreservePackExpansionLevel);
-}
-
-bool OuterSubstitutions::isUnsubstitutedTypeParameter(Type type) const {
-  if (!type->isTypeParameter())
-    return false;
-
-  if (auto depMemTy = type->getAs<DependentMemberType>())
-    return isUnsubstitutedTypeParameter(depMemTy->getBase());
-
-  if (auto genericParam = type->getAs<GenericTypeParamType>())
-    return genericParam->getDepth() >= depth;
+  InFlightSubstitution IFS(replacer, replacer,
+                           SubstFlags::SubstituteOpaqueArchetypes |
+                           SubstFlags::PreservePackExpansionLevel);
+
+  auto substSubs = subs.subst(IFS);
+
+  if (IFS.wasLimitReached()) {
+    ABORT([&](auto &out) {
+      out << "Possible non-terminating type substitution detected\n\n";
+      out << "Original substitution map:\n";
+      subs.dump(out, SubstitutionMap::DumpStyle::NoConformances);
+      out << "Substituted substitution map:\n";
+      substSubs.dump(out, SubstitutionMap::DumpStyle::NoConformances);
+    });
+  }
 
-  return false;
+  return substSubs;
 }
 
 Type OuterSubstitutions::operator()(SubstitutableType *type) const {
-  if (isUnsubstitutedTypeParameter(type))
+  if (cast<GenericTypeParamType>(type)->getDepth() >= depth)
     return Type(type);
 
   return QuerySubstitutionMap{subs}(type);
 }
 
 ProtocolConformanceRef OuterSubstitutions::operator()(
-                                        CanType dependentType,
-                                        Type conformingReplacementType,
+                                        InFlightSubstitution &IFS,
+                                        Type dependentType,
                                         ProtocolDecl *conformedProtocol) const {
-  if (isUnsubstitutedTypeParameter(dependentType))
-    return ProtocolConformanceRef::forAbstract(
-      conformingReplacementType, conformedProtocol);
+  auto sig = subs.getGenericSignature();
+  if (!sig->isValidTypeParameter(dependentType) ||
+      !sig->requiresProtocol(dependentType, conformedProtocol)) {
+    // FIXME: We need the isValidTypeParameter() check instead of just looking
+    // at the root generic parameter because in the case of an existential
+    // environment, the reduced type of a member type of Self might be an outer
+    // type parameter that is not formed from the outer generic signature's
+    // conformance requirements. Ideally, we'd either add these supplementary
+    // conformance requirements to the generalization signature, or we would
+    // store the supplementary conformances directly in the generic environment
+    // somehow.
+    //
+    // Once we check for that and handle it properly, the lookupConformance()
+    // can become a forAbstract().
+    return swift::lookupConformance(
+      dependentType.subst(IFS), conformedProtocol);
+  }
 
   return LookUpConformanceInSubstitutionMap(subs)(
-      dependentType, conformingReplacementType, conformedProtocol);
+      IFS, dependentType, conformedProtocol);
 }
 
diff --git a/lib/AST/SwiftNameTranslation.cpp b/lib/AST/SwiftNameTranslation.cpp
index f675c536dcac7..ed9975acb0339 100644
--- a/lib/AST/SwiftNameTranslation.cpp
+++ b/lib/AST/SwiftNameTranslation.cpp
@@ -16,6 +16,8 @@
 
 #include "swift/AST/SwiftNameTranslation.h"
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/Attr.h"
+#include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/LazyResolver.h"
@@ -27,6 +29,8 @@
 #include "swift/Basic/StringExtras.h"
 
 #include "clang/AST/DeclObjC.h"
+#include "clang/Basic/Module.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include <optional>
 
@@ -48,15 +52,25 @@ getNameForObjC(const ValueDecl *VD, CustomNamesOnly_t customNamesOnly) {
     }
   }
 
+  if (auto cdeclAttr = VD->getAttrs().getAttribute<CDeclAttr>())
+    if (!customNamesOnly || !cdeclAttr->Name.empty())
+      return VD->getCDeclName();
+
   if (customNamesOnly)
     return StringRef();
 
   if (auto clangDecl = dyn_cast_or_null<clang::NamedDecl>(VD->getClangDecl())) {
     if (const clang::IdentifierInfo *II = clangDecl->getIdentifier())
       return II->getName();
-    if (auto *anonDecl = dyn_cast<clang::TagDecl>(clangDecl))
+    if (auto *anonDecl = dyn_cast<clang::TagDecl>(clangDecl)) {
       if (auto *anonTypedef = anonDecl->getTypedefNameForAnonDecl())
         return anonTypedef->getIdentifier()->getName();
+      if (auto *cfOptionsTy =
+              VD->getASTContext()
+                  .getClangModuleLoader()
+                  ->getTypeDefForCXXCFOptionsDefinition(anonDecl))
+        return cfOptionsTy->getDecl()->getName();
+    }
   }
 
   return VD->getBaseIdentifier().str();
@@ -220,15 +234,58 @@ swift::cxx_translation::getNameForCxx(const ValueDecl *VD,
       auto r = ctx.getIdentifier(os.str());
       return r.str();
     }
+  }
 
-    // FIXME: String.Index should be exposed as String::Index, not
-    // _String_Index.
-    if (VD->getBaseIdentifier().str() == "Index") {
-      return "String_Index";
+  return VD->getBaseIdentifier().str();
+}
+
+namespace {
+struct ObjCTypeWalker : TypeWalker {
+  bool hadObjCType = false;
+  const ASTContext &ctx;
+  ObjCTypeWalker(const ASTContext &ctx) : ctx(ctx) {}
+  Action walkToTypePre(Type ty) override {
+    if (auto *nominal = ty->getNominalOrBoundGenericNominal()) {
+      if (auto clangDecl = nominal->getClangDecl()) {
+        if (cxx_translation::isObjCxxOnly(clangDecl, ctx)) {
+          hadObjCType = true;
+          return Action::Stop;
+        }
+      }
     }
+    return Action::Continue;
   }
+};
+} // namespace
 
-  return VD->getBaseIdentifier().str();
+bool swift::cxx_translation::isObjCxxOnly(const ValueDecl *VD) {
+  ObjCTypeWalker walker{VD->getASTContext()};
+  VD->getInterfaceType().walk(walker);
+  return walker.hadObjCType;
+}
+
+bool swift::cxx_translation::isObjCxxOnly(const clang::Decl *D,
+                                          const ASTContext &ctx) {
+  // By default, we import all modules in Obj-C++ mode, so there is no robust
+  // way to tell if something is coming from an Obj-C module. Use the
+  // requirements and the language options to check if we should actually
+  // consider the module to have ObjC constructs.
+  const auto &langOpts = D->getASTContext().getLangOpts();
+  // TODO: have a reasonable guess for headers specified via
+  // `-import-objc-header`.
+  if (!D->hasOwningModule())
+    return false;
+  auto clangModule = D->getOwningModule()->getTopLevelModule();
+  bool requiresObjC = false;
+  for (auto req : clangModule->Requirements)
+    if (req.RequiredState && req.FeatureName == "objc")
+      requiresObjC = true;
+  return langOpts.ObjC &&
+         (requiresObjC ||
+          llvm::any_of(ctx.LangOpts.ModulesRequiringObjC,
+                       [clangModule](StringRef moduleName) {
+                         return clangModule->getFullModuleName() == moduleName;
+                       }));
 }
 
 swift::cxx_translation::DeclRepresentation
@@ -317,6 +374,9 @@ swift::cxx_translation::getDeclRepresentation(
     return {Unsupported, UnrepresentableGenericRequirements};
   }
 
+  if (isObjCxxOnly(VD))
+    return {ObjCxxOnly, std::nullopt};
+
   return {Representable, std::nullopt};
 }
 
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 8153bef6d6276..b7c37172bbd13 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -43,6 +43,7 @@
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/Compiler.h"
+#include "clang/AST/DeclCXX.h"
 #include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
@@ -236,7 +237,6 @@ bool CanType::isReferenceTypeImpl(CanType type, const GenericSignatureImpl *sig,
   // Nothing else is statically just a class reference.
   case TypeKind::SILBlockStorage:
   case TypeKind::Error:
-  case TypeKind::Unresolved:
   case TypeKind::BuiltinInteger:
   case TypeKind::BuiltinIntegerLiteral:
   case TypeKind::BuiltinFloat:
@@ -320,6 +320,8 @@ ExistentialLayout::ExistentialLayout(CanProtocolType type) {
                            !protoDecl->isMarkerProtocol());
   representsAnyObject = false;
 
+  inverses = InvertibleProtocolSet();
+
   protocols.push_back(protoDecl);
   expandDefaults(protocols, InvertibleProtocolSet(), type->getASTContext());
 }
@@ -353,7 +355,7 @@ ExistentialLayout::ExistentialLayout(CanProtocolCompositionType type) {
     protocols.push_back(protoDecl);
   }
 
-  auto inverses = type->getInverses();
+  inverses = type->getInverses();
   expandDefaults(protocols, inverses, type->getASTContext());
 
   representsAnyObject = [&]() {
@@ -433,6 +435,16 @@ Type ExistentialLayout::getSuperclass() const {
   return Type();
 }
 
+bool ExistentialLayout::needsExtendedShape(bool allowInverses) const {
+  if (!getParameterizedProtocols().empty())
+    return true;
+
+  if (allowInverses && hasInverses())
+    return true;
+
+  return false;
+}
+
 bool TypeBase::isObjCExistentialType() {
   return getCanonicalType().isObjCExistentialType();
 }
@@ -748,7 +760,6 @@ bool TypeBase::hasTypeRepr() const {
   return !Type(const_cast<TypeBase *>(this)).findIf([](Type subTy) -> bool {
     switch (subTy->getKind()) {
     case TypeKind::Error:
-    case TypeKind::Unresolved:
     case TypeKind::TypeVariable:
       return true;
 
@@ -829,15 +840,28 @@ CanType CanType::wrapInOptionalTypeImpl(CanType type) {
   return type->wrapInOptionalType()->getCanonicalType();
 }
 
-Type TypeBase::isArrayType() {
-  if (auto boundStruct = getAs<BoundGenericStructType>()) {
-    if (isArray())
-      return boundStruct->getGenericArgs()[0];
+Type TypeBase::getArrayElementType() {
+  if (!isArray())
+    return Type();
 
-    if (isInlineArray())
-      return boundStruct->getGenericArgs()[1];
-  }
-  return Type();
+  if (!is<BoundGenericStructType>())
+    return Type();
+
+  // Array<T>
+  auto boundStruct = castTo<BoundGenericStructType>();
+  return boundStruct->getGenericArgs()[0];
+}
+
+Type TypeBase::getInlineArrayElementType() {
+  if (!isInlineArray())
+    return Type();
+
+  if (!is<BoundGenericStructType>())
+    return Type();
+
+  // InlineArray<n, T>
+  auto boundStruct = castTo<BoundGenericStructType>();
+  return boundStruct->getGenericArgs()[1];
 }
 
 Type TypeBase::getAnyPointerElementType(PointerTypeKind &PTK) {
@@ -1186,6 +1210,15 @@ bool ExistentialLayout::isExistentialWithError(ASTContext &ctx) const {
   return false;
 }
 
+bool ExistentialLayout::containsNonMarkerProtocols() const {
+  for (auto proto : getProtocols()) {
+    if (!proto->isMarkerProtocol())
+      return true;
+  }
+
+  return false;
+}
+
 LayoutConstraint ExistentialLayout::getLayoutConstraint() const {
   if (hasExplicitAnyObject) {
     return LayoutConstraint::getLayoutConstraint(
@@ -1246,6 +1279,62 @@ bool TypeBase::isCGFloat() {
          NTD->getName().is("CGFloat");
 }
 
+bool TypeBase::isObjCBool() {
+  auto *NTD = getAnyNominal();
+  if (!NTD)
+    return false;
+
+  auto *DC = NTD->getDeclContext();
+  if (!DC->isModuleScopeContext())
+    return false;
+
+  auto *module = DC->getParentModule();
+  return module->getName().is("ObjectiveC") && NTD->getName().is("ObjCBool");
+}
+
+bool TypeBase::isCxxString() {
+  auto *nominal = getAnyNominal();
+  if (!nominal)
+    return false;
+
+  auto *clangDecl =
+      dyn_cast_or_null<clang::CXXRecordDecl>(nominal->getClangDecl());
+  if (!clangDecl)
+    return false;
+
+  auto &ctx = nominal->getASTContext();
+  return clangDecl->isInStdNamespace() && clangDecl->getIdentifier() &&
+         ctx.Id_basic_string.is(clangDecl->getName());
+}
+
+bool TypeBase::isUnicodeScalar() {
+  if (!is<StructType>())
+    return false;
+  const auto *structType = castTo<StructType>();
+  if (!structType->getDecl()->getName().is("Scalar"))
+    return false;
+
+  Type parent = structType->getParent();
+  if (!parent->is<EnumType>())
+    return false;
+  const auto enumDecl = parent->castTo<EnumType>()->getDecl();
+  if (!enumDecl->getName().is("Unicode"))
+    return false;
+  const auto *parentDC = enumDecl->getDeclContext();
+  if (!parentDC->isModuleScopeContext() && parentDC->getParentModule()->isStdlibModule())
+    return false;
+  return true;
+}
+
+bool TypeBase::isKnownKeyPathType() {
+  return isKeyPath() || isWritableKeyPath() || isReferenceWritableKeyPath() ||
+         isPartialKeyPath() || isAnyKeyPath();
+}
+
+bool TypeBase::isKnownImmutableKeyPathType() {
+  return isKeyPath() || isPartialKeyPath() || isAnyKeyPath();
+}
+
 bool TypeBase::isKnownStdlibCollectionType() {
   if (isArray() || isDictionary() || isSet()) {
     return true;
@@ -1279,35 +1368,70 @@ Type TypeBase::removeArgumentLabels(unsigned numArgumentLabels) {
   return FunctionType::get(unlabeledParams, result, fnType->getExtInfo());
 }
 
-Type TypeBase::replaceCovariantResultType(Type newResultType,
-                                          unsigned uncurryLevel) {
-  if (uncurryLevel == 0) {
-    bool isLValue = is<LValueType>();
+Type TypeBase::eraseDynamicSelfType() {
+  if (!hasDynamicSelfType())
+    return Type(this);
 
-    auto loadedTy = getWithoutSpecifierType();
-    if (auto objectType = loadedTy->getOptionalObjectType()) {
-      newResultType = OptionalType::get(
-          objectType->replaceCovariantResultType(newResultType, uncurryLevel));
-    }
+  return Type(this).transformWithPosition(
+      TypePosition::Covariant,
+      [&](TypeBase *t, TypePosition pos) -> std::optional<Type> {
+        if (isa<DynamicSelfType>(t) &&
+            pos == TypePosition::Covariant) {
+          return cast<DynamicSelfType>(t)->getSelfType();
+        }
+        return std::nullopt;
+      });
+}
 
-    return isLValue ? LValueType::get(newResultType) : newResultType;
-  }
+Type TypeBase::replaceDynamicSelfType(Type newSelfType) {
+  if (!hasDynamicSelfType())
+    return Type(this);
 
-  // Determine the input and result types of this function.
+  return Type(this).transformWithPosition(
+      TypePosition::Covariant,
+      [&](TypeBase *t, TypePosition pos) -> std::optional<Type> {
+        if (isa<DynamicSelfType>(t) &&
+            pos == TypePosition::Covariant) {
+          return newSelfType;
+        }
+        return std::nullopt;
+      });
+}
+
+Type TypeBase::withCovariantResultType() {
+  // Unwrap the outer function type.
   auto fnType = this->castTo<AnyFunctionType>();
-  auto inputType = fnType->getParams();
-  Type resultType =
-    fnType->getResult()->replaceCovariantResultType(newResultType,
-                                                    uncurryLevel - 1);
+  ASSERT(fnType->getParams().size() == 1);
+
+  // Unwrap the inner function type.
+  auto resultFnType = fnType->getResult()->castTo<FunctionType>();
+  auto resultType = resultFnType->getResult();
 
-  // Produce the resulting function type.
+  bool wasOptional = false;
+  if (auto objectType = resultType->getOptionalObjectType()) {
+    wasOptional = true;
+    resultType = objectType;
+  }
+
+  ASSERT(resultType->getClassOrBoundGenericClass());
+  resultType = DynamicSelfType::get(resultType, getASTContext());
+
+  // Rebuild the inner function type.
+  if (wasOptional)
+    resultType = OptionalType::get(resultType);
+
+  resultFnType = FunctionType::get(resultFnType->getParams(), resultType,
+                                   resultFnType->getExtInfo());
+
+  // Rebuild the outer function type.
   if (auto genericFn = dyn_cast<GenericFunctionType>(fnType)) {
     return GenericFunctionType::get(genericFn->getGenericSignature(),
-                                    inputType, resultType,
+                                    fnType->getParams(), resultFnType,
                                     fnType->getExtInfo());
   }
   
-  return FunctionType::get(inputType, resultType, fnType->getExtInfo());
+  return FunctionType::get(fnType->getParams(), resultFnType,
+                           fnType->getExtInfo());
 }
 
 /// Whether this parameter accepts an unlabeled trailing closure argument
@@ -1344,6 +1468,7 @@ ParameterListInfo::ParameterListInfo(
   propertyWrappers.resize(params.size());
   implicitSelfCapture.resize(params.size());
   inheritActorContext.resize(params.size());
+  alwaysInheritActorContext.resize(params.size());
   variadicGenerics.resize(params.size());
   sendingParameters.resize(params.size());
 
@@ -1400,8 +1525,13 @@ ParameterListInfo::ParameterListInfo(
       implicitSelfCapture.set(i);
     }
 
-    if (param->getAttrs().hasAttribute<InheritActorContextAttr>()) {
-      inheritActorContext.set(i);
+    if (auto *attr =
+            param->getAttrs().getAttribute<InheritActorContextAttr>()) {
+      if (attr->isAlways()) {
+        alwaysInheritActorContext.set(i);
+      } else {
+        inheritActorContext.set(i);
+      }
     }
 
     if (param->getInterfaceType()->is<PackExpansionType>()) {
@@ -1435,10 +1565,18 @@ bool ParameterListInfo::isImplicitSelfCapture(unsigned paramIdx) const {
       : false;
 }
 
-bool ParameterListInfo::inheritsActorContext(unsigned paramIdx) const {
-  return paramIdx < inheritActorContext.size()
-      ? inheritActorContext[paramIdx]
-      : false;
+std::pair<bool, InheritActorContextModifier>
+ParameterListInfo::inheritsActorContext(unsigned paramIdx) const {
+  if (paramIdx >= inheritActorContext.size())
+    return std::make_pair(false, InheritActorContextModifier::None);
+
+  if (inheritActorContext[paramIdx])
+    return std::make_pair(true, InheritActorContextModifier::None);
+
+  if (alwaysInheritActorContext[paramIdx])
+    return std::make_pair(true, InheritActorContextModifier::Always);
+
+  return std::make_pair(false, InheritActorContextModifier::None);
 }
 
 bool ParameterListInfo::isVariadicGenericParameter(unsigned paramIdx) const {
@@ -1646,8 +1784,6 @@ CanType TypeBase::computeCanonicalType() {
 #define ALWAYS_CANONICAL_TYPE(id, parent) case TypeKind::id:
 #define TYPE(id, parent)
 #include "swift/AST/TypeNodes.def"
-  case TypeKind::Error:
-  case TypeKind::Unresolved:
   case TypeKind::TypeVariable:
   case TypeKind::Placeholder:
   case TypeKind::BuiltinTuple:
@@ -1661,6 +1797,14 @@ CanType TypeBase::computeCanonicalType() {
 #define TYPE(id, parent)
 #include "swift/AST/TypeNodes.def"
 
+  case TypeKind::Error: {
+    auto errTy = cast<ErrorType>(this);
+    auto originalTy = errTy->getOriginalType();
+    ASSERT(originalTy && "The bare ErrorType singleton is already canonical");
+    Result = ErrorType::get(originalTy->getCanonicalType()).getPointer();
+    break;
+  }
+
   case TypeKind::Enum:
   case TypeKind::Struct:
   case TypeKind::Class:
@@ -1727,7 +1871,8 @@ CanType TypeBase::computeCanonicalType() {
     auto &C = gpDecl->getASTContext();
     Result =
         GenericTypeParamType::get(gp->getParamKind(), gp->getDepth(),
-                                  gp->getIndex(), gp->getValueType(),
+                                  gp->getIndex(), gp->getWeight(),
+                                  gp->getValueType(),
                                   C);
     break;
   }
@@ -1878,6 +2023,26 @@ CanType TypeBase::computeCanonicalType() {
     Result = ErrorUnionType::get(ctx, newTerms).getPointer();
     break;
   }
+  case TypeKind::OpaqueTypeArchetype: {
+    auto *AT = cast<OpaqueTypeArchetypeType>(this);
+    Result = OpaqueTypeArchetypeType::get(
+        AT->getDecl(), AT->getInterfaceType(),
+        AT->getSubstitutions().getCanonical())
+          ->castTo<OpaqueTypeArchetypeType>();
+    break;
+  }
+  case TypeKind::Integer: {
+    auto intTy = cast<IntegerType>(this);
+    APInt value = intTy->getValue();
+    if (intTy->isNegative()) {
+      value = -value;
+    }
+    SmallString<20> canonicalText;
+    value.toStringUnsigned(canonicalText);
+    Result = IntegerType::get(canonicalText, intTy->isNegative(),
+                              intTy->getASTContext());
+    break;
+  }
   }
 
   // Cache the canonical type for future queries.
@@ -2030,7 +2195,8 @@ GenericSignature TypeAliasType::getGenericSignature() const {
   return typealias->getGenericSignature();
 }
 
-SubstitutionMap TypeAliasType::getSubstitutionMap() const {
+SubstitutionMap
+TypeAliasType::getSubstitutionMap(bool wantContextualType) const {
   auto genericSig = typealias->getGenericSignature();
   if (!genericSig)
     return SubstitutionMap();
@@ -2039,8 +2205,14 @@ SubstitutionMap TypeAliasType::getSubstitutionMap() const {
   DeclContext *dc = typealias->getDeclContext();
 
   if (dc->isLocalContext()) {
-    if (auto parentSig = dc->getGenericSignatureOfContext())
-      parentSubMap = parentSig->getIdentitySubstitutionMap();
+    if (auto parentSig = dc->getGenericSignatureOfContext()) {
+      if (wantContextualType) {
+        parentSubMap =
+            parentSig.getGenericEnvironment()->getForwardingSubstitutionMap();
+      } else {
+        parentSubMap = parentSig->getIdentitySubstitutionMap();
+      }
+    }
   } else if (auto parent = getParent()) {
     parentSubMap = parent->getContextSubstitutionMap(dc);
   }
@@ -2060,8 +2232,9 @@ GenericTypeParamType::GenericTypeParamType(GenericTypeParamDecl *param,
   : SubstitutableType(TypeKind::GenericTypeParam, nullptr, props),
     Decl(param) {
   ASSERT(param->getDepth() != GenericTypeParamDecl::InvalidDepth);
-  Depth = param->getDepth();
   IsDecl = true;
+  Depth = param->getDepth();
+  Weight = 0;
   Index = param->getIndex();
   ParamKind = param->getParamKind();
   ValueType = param->getValueType();
@@ -2074,8 +2247,9 @@ GenericTypeParamType::GenericTypeParamType(Identifier name,
                         canType->getRecursiveProperties()),
       Decl(nullptr) {
   Name = name;
-  Depth = canType->getDepth();
   IsDecl = false;
+  Depth = canType->getDepth();
+  Weight = canType->getWeight();
   Index = canType->getIndex();
   ParamKind = canType->getParamKind();
   ValueType = canType->getValueType();
@@ -2085,13 +2259,16 @@ GenericTypeParamType::GenericTypeParamType(Identifier name,
 
 GenericTypeParamType::GenericTypeParamType(GenericTypeParamKind paramKind,
                                            unsigned depth, unsigned index,
-                                           Type valueType,
+                                           unsigned weight, Type valueType,
                                            RecursiveTypeProperties props,
                                            const ASTContext &ctx)
     : SubstitutableType(TypeKind::GenericTypeParam, &ctx, props),
       Decl(nullptr) {
-  Depth = depth;
+  ASSERT(!(paramKind == GenericTypeParamKind::Value && !valueType) &&
+         "Value generic parameter must have type");
   IsDecl = false;
+  Depth = depth;
+  Weight = weight;
   Index = index;
   ParamKind = paramKind;
   ValueType = valueType;
@@ -2142,6 +2319,15 @@ Type GenericTypeParamType::getValueType() const {
   return ValueType;
 }
 
+GenericTypeParamType *GenericTypeParamType::withDepth(unsigned depth) const {
+  return GenericTypeParamType::get(getParamKind(),
+                                   depth,
+                                   getIndex(),
+                                   getWeight(),
+                                   getValueType(),
+                                   getASTContext());
+}
+
 const llvm::fltSemantics &BuiltinFloatType::getAPFloatSemantics() const {
   switch (getFPKind()) {
   case BuiltinFloatType::IEEE16:  return APFloat::IEEEhalf();
@@ -2163,10 +2349,9 @@ bool TypeBase::mayBeCallable(DeclContext *dc) {
     return true;
 
   // Unresolved types that could potentially be callable.
-  if (isPlaceholder() || is<UnresolvedType>() ||
-      isTypeParameter() || isTypeVariableOrMember()) {
+  if (isPlaceholder() || isTypeParameter() || isTypeVariableOrMember())
     return true;
-  }
+
   // Callable nominal types.
   if (isCallAsFunctionType(dc) || hasDynamicCallableAttribute())
     return true;
@@ -2214,10 +2399,24 @@ Type TypeBase::getSuperclass(bool useArchetypes) {
   Type superclassTy = classDecl->getSuperclass();
 
   // If there's no superclass, or it is fully concrete, we're done.
-  if (!superclassTy || !superclassTy->hasTypeParameter() ||
-      hasUnboundGenericType())
+  if (!superclassTy || !superclassTy->hasTypeParameter())
     return superclassTy;
 
+  auto hasUnboundGenericType = [&]() {
+    Type t(this);
+    while (t) {
+      if (t->is<UnboundGenericType>())
+        return true;
+      t = t->getNominalParent();
+    }
+    return false;
+  };
+
+  // If we started with an UnboundGenericType, we cannot apply the
+  // context substitution map. Return the unbound form of the superclass.
+  if (hasUnboundGenericType())
+    return superclassTy->getAnyNominal()->getDeclaredType();
+
   // Gather substitutions from the self type, and apply them to the original
   // superclass type to form the substituted superclass type.
   auto subMap = getContextSubstitutionMap(classDecl,
@@ -2755,6 +2954,11 @@ static bool hasRetainablePointerRepresentation(CanType type) {
     type = objType;
   }
 
+  // C++ imported `SWIFT_SHARED_REFERENCE` classes are not compatible with
+  // Swift's retain/release runtime functions.
+  if (type.isForeignReferenceType())
+    return false;
+
   return isBridgeableObjectType(type);
 }
 
@@ -3007,6 +3211,12 @@ getForeignRepresentable(Type type, ForeignLanguage language,
       // Imported classes and protocols are not representable in C.
       if (isa<ClassDecl>(nominal) || isa<ProtocolDecl>(nominal))
         return failure();
+
+      // @objc enums are not representable in C, @c ones and imported ones
+      // are ok.
+      if (!nominal->hasClangNode())
+        return failure();
+
       LLVM_FALLTHROUGH;
 
     case ForeignLanguage::ObjectiveC:
@@ -3045,6 +3255,11 @@ getForeignRepresentable(Type type, ForeignLanguage language,
     }
   }
 
+  // @c enums are representable in C and Objective-C.
+  if (nominal->getAttrs().getAttribute<CDeclAttr>()) {
+    return { ForeignRepresentableKind::Trivial, nullptr };
+  }
+
   // Pointers may be representable in ObjC.
   PointerTypeKind pointerKind;
   if (auto pointerElt = type->getAnyPointerElementType(pointerKind)) {
@@ -3466,7 +3681,7 @@ bool TypeBase::matchesFunctionType(Type other, TypeMatchOptions matchMode,
 /// return the field index, otherwise return -1.
 int TupleType::getNamedElementId(Identifier I) const {
   for (unsigned i = 0, e = Bits.TupleType.Count; i != e; ++i) {
-    if (getTrailingObjects<TupleTypeElt>()[i].getName() == I)
+    if (getTrailingObjects()[i].getName() == I)
       return i;
   }
 
@@ -3475,13 +3690,13 @@ int TupleType::getNamedElementId(Identifier I) const {
 }
 
 ArchetypeType::ArchetypeType(TypeKind Kind,
-                             const ASTContext &Ctx,
+                             const ASTContext *Ctx,
                              RecursiveTypeProperties properties,
                              Type InterfaceType,
                              ArrayRef<ProtocolDecl *> ConformsTo,
                              Type Superclass, LayoutConstraint Layout,
                              GenericEnvironment *Environment)
-  : SubstitutableType(Kind, &Ctx, properties),
+  : SubstitutableType(Kind, Ctx, properties),
     InterfaceType(InterfaceType),
     Environment(Environment)
 {
@@ -3615,7 +3830,7 @@ PrimaryArchetypeType::PrimaryArchetypeType(const ASTContext &Ctx,
                                      ArrayRef<ProtocolDecl *> ConformsTo,
                                      Type Superclass, LayoutConstraint Layout,
                                      RecursiveTypeProperties Properties)
-  : ArchetypeType(TypeKind::PrimaryArchetype, Ctx, Properties,
+  : ArchetypeType(TypeKind::PrimaryArchetype, &Ctx, Properties,
                   InterfaceType, ConformsTo, Superclass, Layout, GenericEnv)
 {
   assert(!InterfaceType->isParameterPack());
@@ -3651,12 +3866,13 @@ PrimaryArchetypeType::getNew(const ASTContext &Ctx,
 }
 
 OpaqueTypeArchetypeType::OpaqueTypeArchetypeType(
+    const ASTContext *ctx,
     GenericEnvironment *environment,
     RecursiveTypeProperties properties,
     Type interfaceType,
     ArrayRef<ProtocolDecl*> conformsTo,
     Type superclass, LayoutConstraint layout)
-  : ArchetypeType(TypeKind::OpaqueTypeArchetype, interfaceType->getASTContext(),
+  : ArchetypeType(TypeKind::OpaqueTypeArchetype, ctx,
                   properties, interfaceType, conformsTo, superclass, layout,
                   environment)
 {
@@ -3672,11 +3888,10 @@ SubstitutionMap OpaqueTypeArchetypeType::getSubstitutions() const {
 }
 
 ExistentialArchetypeType::ExistentialArchetypeType(
-    GenericEnvironment *environment, Type interfaceType,
+    const ASTContext *ctx, GenericEnvironment *environment, Type interfaceType,
     ArrayRef<ProtocolDecl *> conformsTo, Type superclass,
     LayoutConstraint layout, RecursiveTypeProperties properties)
-  : LocalArchetypeType(TypeKind::ExistentialArchetype,
-                       interfaceType->getASTContext(), properties,
+  : LocalArchetypeType(TypeKind::ExistentialArchetype, ctx, properties,
                        interfaceType, conformsTo, superclass, layout,
                        environment)
 {
@@ -3688,7 +3903,7 @@ PackArchetypeType::PackArchetypeType(
     ArrayRef<ProtocolDecl *> ConformsTo, Type Superclass,
     LayoutConstraint Layout, PackShape Shape,
     RecursiveTypeProperties Properties)
-  : ArchetypeType(TypeKind::PackArchetype, Ctx, Properties,
+  : ArchetypeType(TypeKind::PackArchetype, &Ctx, Properties,
                     InterfaceType, ConformsTo, Superclass, Layout, GenericEnv) {
   assert(InterfaceType->isParameterPack());
   *getTrailingObjects<PackShape>() = Shape;
@@ -3740,7 +3955,7 @@ CanType PackArchetypeType::getReducedShape() {
 }
 
 ElementArchetypeType::ElementArchetypeType(
-    const ASTContext &Ctx, GenericEnvironment *GenericEnv, Type InterfaceType,
+    const ASTContext *Ctx, GenericEnvironment *GenericEnv, Type InterfaceType,
     ArrayRef<ProtocolDecl *> ConformsTo, Type Superclass,
     LayoutConstraint Layout)
     : LocalArchetypeType(TypeKind::ElementArchetype, Ctx,
@@ -3766,7 +3981,8 @@ CanTypeWrapper<ElementArchetypeType> ElementArchetypeType::getNew(
       alignof(ElementArchetypeType), arena);
 
   return CanElementArchetypeType(::new (mem) ElementArchetypeType(
-      ctx, environment, interfaceType, conformsTo, superclass, layout));
+      environment->isCanonical() ? &ctx : nullptr,
+      environment, interfaceType, conformsTo, superclass, layout));
 }
 
 UUID ElementArchetypeType::getOpenedElementID() const {
@@ -3802,7 +4018,7 @@ ParameterizedProtocolType::ParameterizedProtocolType(
   assert(args.size() > 0);
   Bits.ParameterizedProtocolType.ArgCount = args.size();
   for (unsigned i : indices(args))
-    getTrailingObjects<Type>()[i] = args[i];
+    getTrailingObjects()[i] = args[i];
 }
 
 void ParameterizedProtocolType::Profile(llvm::FoldingSetNodeID &ID,
@@ -4171,10 +4387,10 @@ bool TypeBase::isNoEscape() const {
 }
 
 Identifier DependentMemberType::getName() const {
-  if (NameOrAssocType.is<Identifier>())
-    return NameOrAssocType.get<Identifier>();
+  if (isa<Identifier>(NameOrAssocType))
+    return cast<Identifier>(NameOrAssocType);
 
-  return NameOrAssocType.get<AssociatedTypeDecl *>()->getName();
+  return cast<AssociatedTypeDecl *>(NameOrAssocType)->getName();
 }
 
 Type Type::transformRec(
@@ -4228,6 +4444,12 @@ bool Type::findIf(llvm::function_ref<bool(Type)> pred) const {
 }
 
 TypeTraitResult TypeBase::canBeClass() {
+  // Foreign reference types are represented as Swift classes in the AST,
+  // however, they use custom retain/release operations, and therefore aren't
+  // AnyObjects.
+  if (isForeignReferenceType())
+    return TypeTraitResult::IsNot;
+
   // Any bridgeable object type can be a class.
   if (isBridgeableObjectType())
     return TypeTraitResult::Is;
@@ -4383,7 +4605,6 @@ ReferenceCounting TypeBase::getReferenceCounting() {
   case TypeKind::SILFunction:
   case TypeKind::SILBlockStorage:
   case TypeKind::Error:
-  case TypeKind::Unresolved:
   case TypeKind::BuiltinInteger:
   case TypeKind::BuiltinIntegerLiteral:
   case TypeKind::BuiltinFloat:
@@ -4569,7 +4790,7 @@ TypeBase::getAutoDiffTangentSpace(LookupConformanceFn lookupConformance) {
   // Try to get the `TangentVector` associated type of `base`.
   // Return the associated type if it is valid.
   auto conformance = swift::lookupConformance(this, differentiableProtocol);
-  auto assocTy = conformance.getTypeWitness(this, assocDecl);
+  auto assocTy = conformance.getTypeWitness(assocDecl);
   if (!assocTy->hasError())
     return cache(TangentSpace::getTangentVector(assocTy));
 
@@ -4768,7 +4989,8 @@ AnyFunctionType::getAutoDiffDerivativeFunctionLinearMapType(
     if (!resultTan)
       return llvm::make_error<DerivativeFunctionTypeError>(
         this, DerivativeFunctionTypeError::Kind::NonDifferentiableResult,
-        std::make_pair(originalResultType, unsigned(originalResult.index)));
+        DerivativeFunctionTypeError::TypeAndIndex(
+          originalResultType, unsigned(originalResult.index)));
 
     if (!originalResult.isSemanticResultParameter)
       resultTanTypes.push_back(resultTan->getType());
@@ -4798,7 +5020,7 @@ AnyFunctionType::getAutoDiffDerivativeFunctionLinearMapType(
             this,
             DerivativeFunctionTypeError::Kind::
                 NonDifferentiableDifferentiabilityParameter,
-            std::make_pair(paramType, i));
+            DerivativeFunctionTypeError::TypeAndIndex(paramType, i));
 
       differentialParams.push_back(AnyFunctionType::Param(
           paramTan->getType(), Identifier(), diffParam.getParameterFlags()));
@@ -4846,7 +5068,7 @@ AnyFunctionType::getAutoDiffDerivativeFunctionLinearMapType(
             this,
             DerivativeFunctionTypeError::Kind::
                 NonDifferentiableDifferentiabilityParameter,
-            std::make_pair(paramType, i));
+            DerivativeFunctionTypeError::TypeAndIndex(paramType, i));
 
       if (diffParam.isAutoDiffSemanticResult()) {
         if (paramType->isVoid())
@@ -4994,11 +5216,15 @@ StringRef swift::getNameForParamSpecifier(ParamSpecifier specifier) {
   llvm_unreachable("bad ParamSpecifier");
 }
 
-std::optional<DiagnosticBehavior>
-TypeBase::getConcurrencyDiagnosticBehaviorLimit(DeclContext *declCtx) const {
-  auto *self = const_cast<TypeBase *>(this);
+static std::optional<DiagnosticBehavior>
+getConcurrencyDiagnosticBehaviorLimitRec(
+    Type type, DeclContext *declCtx,
+    llvm::SmallPtrSetImpl<NominalTypeDecl *> &visited) {
+  if (auto *nomDecl = type->getNominalOrBoundGenericNominal()) {
+    // If we have already seen this type, treat it as having no limit.
+    if (!visited.insert(nomDecl).second)
+      return std::nullopt;
 
-  if (auto *nomDecl = self->getNominalOrBoundGenericNominal()) {
     // First try to just grab the exact concurrency diagnostic behavior.
     if (auto result =
             swift::getConcurrencyDiagnosticBehaviorLimit(nomDecl, declCtx)) {
@@ -5009,11 +5235,12 @@ TypeBase::getConcurrencyDiagnosticBehaviorLimit(DeclContext *declCtx) const {
     // merging our fields if we have a struct.
     if (auto *structDecl = dyn_cast<StructDecl>(nomDecl)) {
       std::optional<DiagnosticBehavior> diagnosticBehavior;
-      auto substMap = self->getContextSubstitutionMap();
+      auto substMap = type->getContextSubstitutionMap();
       for (auto storedProperty : structDecl->getStoredProperties()) {
         auto lhs = diagnosticBehavior.value_or(DiagnosticBehavior::Unspecified);
         auto astType = storedProperty->getInterfaceType().subst(substMap);
-        auto rhs = astType->getConcurrencyDiagnosticBehaviorLimit(declCtx);
+        auto rhs = getConcurrencyDiagnosticBehaviorLimitRec(astType, declCtx,
+                                                            visited);
         auto result = lhs.merge(rhs.value_or(DiagnosticBehavior::Unspecified));
         if (result != DiagnosticBehavior::Unspecified)
           diagnosticBehavior = result;
@@ -5024,13 +5251,14 @@ TypeBase::getConcurrencyDiagnosticBehaviorLimit(DeclContext *declCtx) const {
 
   // When attempting to determine the diagnostic behavior limit of a tuple, just
   // merge for each of the elements.
-  if (auto *tupleType = self->getAs<TupleType>()) {
+  if (auto *tupleType = type->getAs<TupleType>()) {
     std::optional<DiagnosticBehavior> diagnosticBehavior;
     for (auto tupleType : tupleType->getElements()) {
       auto lhs = diagnosticBehavior.value_or(DiagnosticBehavior::Unspecified);
 
       auto type = tupleType.getType()->getCanonicalType();
-      auto rhs = type->getConcurrencyDiagnosticBehaviorLimit(declCtx);
+      auto rhs = getConcurrencyDiagnosticBehaviorLimitRec(type, declCtx,
+                                                          visited);
       auto result = lhs.merge(rhs.value_or(DiagnosticBehavior::Unspecified));
       if (result != DiagnosticBehavior::Unspecified)
         diagnosticBehavior = result;
@@ -5038,7 +5266,21 @@ TypeBase::getConcurrencyDiagnosticBehaviorLimit(DeclContext *declCtx) const {
     return diagnosticBehavior;
   }
 
-  return {};
+  // Metatypes that aren't Sendable were introduced in Swift 6.2, so downgrade
+  // them to warnings prior to Swift 7.
+  if (type->is<AnyMetatypeType>()) {
+    if (!type->getASTContext().LangOpts.isSwiftVersionAtLeast(7))
+      return DiagnosticBehavior::Warning;
+  }
+
+  return std::nullopt;
+}
+
+std::optional<DiagnosticBehavior>
+TypeBase::getConcurrencyDiagnosticBehaviorLimit(DeclContext *declCtx) const {
+  auto *self = const_cast<TypeBase *>(this);
+  llvm::SmallPtrSet<NominalTypeDecl *, 16> visited;
+  return getConcurrencyDiagnosticBehaviorLimitRec(Type(self), declCtx, visited);
 }
 
 GenericTypeParamKind
diff --git a/lib/AST/TypeCheckRequests.cpp b/lib/AST/TypeCheckRequests.cpp
index d20c0b72d453f..a4debbb322221 100644
--- a/lib/AST/TypeCheckRequests.cpp
+++ b/lib/AST/TypeCheckRequests.cpp
@@ -48,7 +48,7 @@ void swift::simple_display(
     return;
   }
 
-  auto ext = value.get<const ExtensionDecl *>();
+  auto ext = cast<const ExtensionDecl *>(value);
   simple_display(out, ext);
 }
 
@@ -123,7 +123,7 @@ ASTContext &InheritedTypeRequest::getASTContext() const {
   if (auto *td = declUnion.dyn_cast<const TypeDecl *>()) {
     return td->getASTContext();
   }
-  return declUnion.get<const ExtensionDecl *>()->getASTContext();
+  return cast<const ExtensionDecl *>(declUnion)->getASTContext();
 }
 
 SourceLoc InheritedTypeRequest::getNearestLoc() const {
@@ -217,8 +217,7 @@ void EnumRawTypeRequest::diagnoseCycle(DiagnosticEngine &diags) const {
 
 void EnumRawTypeRequest::noteCycleStep(DiagnosticEngine &diags) const {
   auto *decl = std::get<0>(getStorage());
-  diags.diagnose(decl, diag::kind_declname_declared_here,
-                 decl->getDescriptiveKind(), decl->getName());
+  diags.diagnose(decl, diag::through_decl_declared_here_with_kind, decl);
 }
 
 //----------------------------------------------------------------------------//
@@ -248,10 +247,8 @@ void ProtocolRequiresClassRequest::diagnoseCycle(DiagnosticEngine &diags) const
 }
 
 void ProtocolRequiresClassRequest::noteCycleStep(DiagnosticEngine &diags) const {
-  auto requirement = std::get<0>(getStorage());
-  diags.diagnose(requirement, diag::kind_declname_declared_here,
-                 DescriptiveDeclKind::Protocol,
-                 requirement->getName());
+  auto *proto = std::get<0>(getStorage());
+  diags.diagnose(proto, diag::through_decl_declared_here_with_kind, proto);
 }
 
 std::optional<bool> ProtocolRequiresClassRequest::getCachedResult() const {
@@ -274,9 +271,8 @@ void ExistentialConformsToSelfRequest::diagnoseCycle(DiagnosticEngine &diags) co
 }
 
 void ExistentialConformsToSelfRequest::noteCycleStep(DiagnosticEngine &diags) const {
-  auto requirement = std::get<0>(getStorage());
-  diags.diagnose(requirement, diag::kind_declname_declared_here,
-                 DescriptiveDeclKind::Protocol, requirement->getName());
+  auto *proto = std::get<0>(getStorage());
+  diags.diagnose(proto, diag::through_decl_declared_here_with_kind, proto);
 }
 
 std::optional<bool> ExistentialConformsToSelfRequest::getCachedResult() const {
@@ -301,9 +297,8 @@ void HasSelfOrAssociatedTypeRequirementsRequest::diagnoseCycle(
 
 void HasSelfOrAssociatedTypeRequirementsRequest::noteCycleStep(
     DiagnosticEngine &diags) const {
-  auto requirement = std::get<0>(getStorage());
-  diags.diagnose(requirement, diag::kind_declname_declared_here,
-                 DescriptiveDeclKind::Protocol, requirement->getName());
+  auto *proto = std::get<0>(getStorage());
+  diags.diagnose(proto, diag::through_decl_declared_here_with_kind, proto);
 }
 
 std::optional<bool>
@@ -473,7 +468,7 @@ WhereClauseOwner::WhereClauseOwner(AssociatedTypeDecl *atd)
 SourceLoc WhereClauseOwner::getLoc() const {
   if (auto genericParams = source.dyn_cast<GenericParamList *>()) {
     return genericParams->getWhereLoc();
-  } else if (auto attr = source.dyn_cast<SpecializeAttr *>()) {
+  } else if (auto attr = source.dyn_cast<AbstractSpecializeAttr *>()) {
     return attr->getLocation();
   } else if (auto attr = source.dyn_cast<DifferentiableAttr *>()) {
     return attr->getLocation();
@@ -486,11 +481,14 @@ SourceLoc WhereClauseOwner::getLoc() const {
 
 void swift::simple_display(llvm::raw_ostream &out,
                            const WhereClauseOwner &owner) {
-  if (owner.source.is<TrailingWhereClause *>()) {
+  if (isa<TrailingWhereClause *>(owner.source)) {
     simple_display(out, owner.dc->getAsDecl());
-  } else if (owner.source.is<SpecializeAttr *>()) {
-    out << "@_specialize";
-  } else if (owner.source.is<DifferentiableAttr *>()) {
+  } else if (auto attr = owner.source.dyn_cast<AbstractSpecializeAttr *>()) {
+    if (attr->isPublic())
+      out << "@specialized";
+    else
+      out << "@_specialize";
+  } else if (isa<DifferentiableAttr *>(owner.source)) {
     out << "@_differentiable";
   } else {
     out << "(SIL generic parameter list)";
@@ -513,13 +511,13 @@ void RequirementRequest::noteCycleStep(DiagnosticEngine &diags) const {
 MutableArrayRef<RequirementRepr> WhereClauseOwner::getRequirements() const {
   if (const auto genericParams = source.dyn_cast<GenericParamList *>()) {
     return genericParams->getRequirements();
-  } else if (const auto attr = source.dyn_cast<SpecializeAttr *>()) {
+  } else if (const auto attr = source.dyn_cast<AbstractSpecializeAttr *>()) {
     if (auto whereClause = attr->getTrailingWhereClause())
       return whereClause->getRequirements();
   } else if (const auto attr = source.dyn_cast<DifferentiableAttr *>()) {
     if (auto whereClause = attr->getWhereClause())
       return whereClause->getRequirements();
-  } else if (const auto whereClause = source.get<TrailingWhereClause *>()) {
+  } else if (const auto whereClause = cast<TrailingWhereClause *>(source)) {
     return whereClause->getRequirements();
   }
 
@@ -1224,11 +1222,16 @@ std::optional<Type> InterfaceTypeRequest::getCachedResult() const {
 void InterfaceTypeRequest::cacheResult(Type type) const {
   auto *decl = std::get<0>(getStorage());
   if (type) {
-    assert(!type->hasTypeVariable() && "Type variable in interface type");
-    assert(!type->is<InOutType>() && "Interface type must be materializable");
-    assert(!type->hasPrimaryArchetype() && "Archetype in interface type");
-    assert(decl->getDeclContext()->isLocalContext() || !type->hasLocalArchetype() &&
+    ASSERT(!type->hasTypeVariable() && "Type variable in interface type");
+    ASSERT(!type->is<InOutType>() && "Interface type must be materializable");
+    ASSERT(!type->hasPrimaryArchetype() && "Archetype in interface type");
+    ASSERT(decl->getDeclContext()->isLocalContext() || !type->hasLocalArchetype() &&
            "Local archetype in interface type of non-local declaration");
+    // Placeholders are only permitted in closure parameters.
+    if (!(isa<ParamDecl>(decl) &&
+          isa<AbstractClosureExpr>(decl->getDeclContext()))) {
+      ASSERT(!type->hasPlaceholder() && "Placeholder in interface type");
+    }
   }
   decl->TypeAndAccess.setPointer(type);
 }
@@ -1369,6 +1372,38 @@ void AssociatedConformanceRequest::cacheResult(
   conformance->setAssociatedConformance(index, assocConf);
 }
 
+//----------------------------------------------------------------------------//
+// RawConformanceIsolationRequest computation.
+//----------------------------------------------------------------------------//
+std::optional<std::optional<ActorIsolation>>
+RawConformanceIsolationRequest::getCachedResult() const {
+  // We only want to cache for global-actor-isolated conformances. For
+  // everything else, which is nearly every conformance, this request quickly
+  // returns "nonisolated" so there is no point in caching it.
+  auto conformance = std::get<0>(getStorage());
+
+  // Was actor isolation non-isolated?
+  if (conformance->isRawIsolationInferred())
+    return std::optional<ActorIsolation>();
+
+  ASTContext &ctx = conformance->getDeclContext()->getASTContext();
+  return ctx.evaluator.getCachedNonEmptyOutput(*this);
+}
+
+void RawConformanceIsolationRequest::cacheResult(
+    std::optional<ActorIsolation> result) const {
+  auto conformance = std::get<0>(getStorage());
+
+  // Common case: conformance is inferred, so there's no result.
+  if (!result) {
+    conformance->setRawConformanceInferred();
+    return;
+  }
+
+  ASTContext &ctx = conformance->getDeclContext()->getASTContext();
+  ctx.evaluator.cacheNonEmptyOutput(*this, std::move(result));
+}
+
 //----------------------------------------------------------------------------//
 // ConformanceIsolationRequest computation.
 //----------------------------------------------------------------------------//
@@ -1378,31 +1413,25 @@ ConformanceIsolationRequest::getCachedResult() const {
   // everything else, which is nearly every conformance, this request quickly
   // returns "nonisolated" so there is no point in caching it.
   auto conformance = std::get<0>(getStorage());
-  auto rootNormal =
-      dyn_cast<NormalProtocolConformance>(conformance->getRootConformance());
-  if (!rootNormal)
-    return ActorIsolation::forNonisolated(false);
 
   // Was actor isolation non-isolated?
-  if (rootNormal->isComputedNonisolated())
+  if (conformance->isComputedNonisolated())
     return ActorIsolation::forNonisolated(false);
 
-  ASTContext &ctx = rootNormal->getDeclContext()->getASTContext();
+  ASTContext &ctx = conformance->getDeclContext()->getASTContext();
   return ctx.evaluator.getCachedNonEmptyOutput(*this);
 }
 
 void ConformanceIsolationRequest::cacheResult(ActorIsolation result) const {
   auto conformance = std::get<0>(getStorage());
-  auto rootNormal =
-      cast<NormalProtocolConformance>(conformance->getRootConformance());
 
   // Common case: conformance is nonisolated.
   if (result.isNonisolated()) {
-    rootNormal->setComputedNonnisolated();
+    conformance->setComputedNonnisolated();
     return;
   }
 
-  ASTContext &ctx = rootNormal->getDeclContext()->getASTContext();
+  ASTContext &ctx = conformance->getDeclContext()->getASTContext();
   ctx.evaluator.cacheNonEmptyOutput(*this, std::move(result));
 }
 
@@ -1419,8 +1448,7 @@ void HasCircularInheritedProtocolsRequest::diagnoseCycle(
 void HasCircularInheritedProtocolsRequest::noteCycleStep(
     DiagnosticEngine &diags) const {
   auto *decl = std::get<0>(getStorage());
-  diags.diagnose(decl, diag::kind_declname_declared_here,
-                 decl->getDescriptiveKind(), decl->getName());
+  diags.diagnose(decl, diag::through_decl_declared_here_with_kind, decl);
 }
 
 //----------------------------------------------------------------------------//
@@ -1434,8 +1462,7 @@ void HasCircularRawValueRequest::diagnoseCycle(DiagnosticEngine &diags) const {
 
 void HasCircularRawValueRequest::noteCycleStep(DiagnosticEngine &diags) const {
   auto *decl = std::get<0>(getStorage());
-  diags.diagnose(decl, diag::kind_declname_declared_here,
-                 decl->getDescriptiveKind(), decl->getName());
+  diags.diagnose(decl, diag::through_decl_declared_here_with_kind, decl);
 }
 
 //----------------------------------------------------------------------------//
@@ -1467,7 +1494,7 @@ std::optional<Expr *> DefaultArgumentExprRequest::getCachedResult() const {
   if (!defaultInfo->InitContextAndIsTypeChecked.getInt())
     return std::nullopt;
 
-  return defaultInfo->DefaultArg.get<Expr *>();
+  return cast<Expr *>(defaultInfo->DefaultArg);
 }
 
 void DefaultArgumentExprRequest::cacheResult(Expr *expr) const {
@@ -2029,6 +2056,17 @@ void ActorIsolation::dumpForDiagnostics() const {
   llvm::dbgs() << '\n';
 }
 
+unsigned ActorIsolation::getActorInstanceUnionIndex() const {
+  assert(isActorInstanceIsolated());
+  if (isa<NominalTypeDecl *>(actorInstance))
+    return 0;
+  if (isa<VarDecl *>(actorInstance))
+    return 1;
+  if (isa<Expr *>(actorInstance))
+    return 2;
+  llvm_unreachable("Unhandled");
+}
+
 void swift::simple_display(
     llvm::raw_ostream &out, const ActorIsolation &state) {
   if (state.preconcurrency())
@@ -2165,7 +2203,7 @@ GlobalActorAttributeRequest::getCachedResult() const {
 
     return decl->getASTContext().evaluator.getCachedNonEmptyOutput(*this);
   } else {
-    auto closure = subject.get<ClosureExpr *>();
+    auto closure = cast<ClosureExpr *>(subject);
     if (closure->hasNoGlobalActorAttribute())
       return std::optional(std::optional<CustomAttrNominalPair>());
 
@@ -2186,7 +2224,7 @@ GlobalActorAttributeRequest::cacheResult(std::optional<CustomAttrNominalPair> va
 
     decl->getASTContext().evaluator.cacheNonEmptyOutput(*this, std::move(value));
   } else {
-    auto closure = subject.get<ClosureExpr *>();
+    auto closure = cast<ClosureExpr *>(subject);
     if (!value) {
       closure->setHasNoGlobalActorAttribute();
       return;
@@ -2295,10 +2333,10 @@ ArgumentList *UnresolvedMacroReference::getArgs() const {
 }
 
 MacroRoles UnresolvedMacroReference::getMacroRoles() const {
-  if (pointer.is<FreestandingMacroExpansion *>())
+  if (isa<FreestandingMacroExpansion *>(pointer))
     return getFreestandingMacroRoles();
 
-  if (pointer.is<CustomAttr *>())
+  if (isa<CustomAttr *>(pointer))
     return getAttachedMacroRoles();
 
   llvm_unreachable("Unsupported macro reference");
@@ -2701,24 +2739,36 @@ void ExpandBodyMacroRequest::noteCycleStep(DiagnosticEngine &diags) const {
 
 std::optional<std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>>
 LifetimeDependenceInfoRequest::getCachedResult() const {
-  auto *func = std::get<0>(getStorage());
+  auto *decl = std::get<0>(getStorage());
+  bool noLifetimeDependenceInfo;
 
-  if (func->LazySemanticInfo.NoLifetimeDependenceInfo)
+  if (auto *func = dyn_cast<AbstractFunctionDecl>(decl)) {
+    noLifetimeDependenceInfo = func->LazySemanticInfo.NoLifetimeDependenceInfo;
+  } else {
+    auto *eed = cast<EnumElementDecl>(decl);
+    noLifetimeDependenceInfo = eed->LazySemanticInfo.NoLifetimeDependenceInfo;
+  }
+
+  if (noLifetimeDependenceInfo)
     return std::optional(std::optional<LifetimeDependenceInfo>());
 
-  return func->getASTContext().evaluator.getCachedNonEmptyOutput(*this);
+  return decl->getASTContext().evaluator.getCachedNonEmptyOutput(*this);
 }
 
 void LifetimeDependenceInfoRequest::cacheResult(
     std::optional<llvm::ArrayRef<LifetimeDependenceInfo>> result) const {
-  auto *func = std::get<0>(getStorage());
-  
+  auto *decl = std::get<0>(getStorage());
+
   if (!result) {
-    func->LazySemanticInfo.NoLifetimeDependenceInfo = 1;
-    return;
+    if (auto *func = dyn_cast<AbstractFunctionDecl>(decl)) {
+      func->LazySemanticInfo.NoLifetimeDependenceInfo = 1;
+      return;
+    }
+    auto *eed = cast<EnumElementDecl>(decl);
+    eed->LazySemanticInfo.NoLifetimeDependenceInfo = 1;
   }
 
-  func->getASTContext().evaluator.cacheNonEmptyOutput(*this, std::move(result));
+  decl->getASTContext().evaluator.cacheNonEmptyOutput(*this, std::move(result));
 }
 
 //----------------------------------------------------------------------------//
@@ -2751,6 +2801,23 @@ void ParamCaptureInfoRequest::cacheResult(CaptureInfo info) const {
   param->setDefaultArgumentCaptureInfo(info);
 }
 
+//----------------------------------------------------------------------------//
+// PatternBindingCaptureInfoRequest caching.
+//----------------------------------------------------------------------------//
+
+std::optional<CaptureInfo>
+PatternBindingCaptureInfoRequest::getCachedResult() const {
+  auto *PBD = std::get<0>(getStorage());
+  auto idx = std::get<1>(getStorage());
+  return PBD->getPatternList()[idx].getCachedCaptureInfo();
+}
+
+void PatternBindingCaptureInfoRequest::cacheResult(CaptureInfo info) const {
+  auto *PBD = std::get<0>(getStorage());
+  auto idx = std::get<1>(getStorage());
+  PBD->getMutablePatternList()[idx].setCaptureInfo(info);
+}
+
 //----------------------------------------------------------------------------//
 // SemanticAvailableAttrRequest computation.
 //----------------------------------------------------------------------------//
@@ -2775,3 +2842,48 @@ void SemanticAvailableAttrRequest::cacheResult(
   if (!value)
     attr->setInvalid();
 }
+
+//----------------------------------------------------------------------------//
+// AvailabilityDomainForDeclRequest computation.
+//----------------------------------------------------------------------------//
+
+std::optional<std::optional<AvailabilityDomain>>
+AvailabilityDomainForDeclRequest::getCachedResult() const {
+  auto decl = std::get<0>(getStorage());
+
+  if (decl->LazySemanticInfo.noAvailabilityDomain)
+    return std::optional<AvailabilityDomain>();
+  return decl->getASTContext().evaluator.getCachedNonEmptyOutput(*this);
+}
+
+void AvailabilityDomainForDeclRequest::cacheResult(
+    std::optional<AvailabilityDomain> domain) const {
+  auto decl = std::get<0>(getStorage());
+
+  if (!domain) {
+    decl->LazySemanticInfo.noAvailabilityDomain = 1;
+    return;
+  }
+
+  decl->getASTContext().evaluator.cacheNonEmptyOutput(*this, std::move(domain));
+}
+
+//----------------------------------------------------------------------------//
+// IsCustomAvailabilityDomainPermanentlyEnabled computation.
+//----------------------------------------------------------------------------//
+std::optional<bool>
+IsCustomAvailabilityDomainPermanentlyEnabled::getCachedResult() const {
+  auto *domain = std::get<0>(getStorage());
+
+  if (domain->flags.isPermanentlyEnabledComputed)
+    return domain->flags.isPermanentlyEnabled;
+  return std::nullopt;
+}
+
+void IsCustomAvailabilityDomainPermanentlyEnabled::cacheResult(
+    bool isPermanentlyEnabled) const {
+  auto *domain = const_cast<CustomAvailabilityDomain *>(std::get<0>(getStorage()));
+
+  domain->flags.isPermanentlyEnabledComputed = true;
+  domain->flags.isPermanentlyEnabled = isPermanentlyEnabled;
+}
diff --git a/lib/AST/TypeRepr.cpp b/lib/AST/TypeRepr.cpp
index 0980e8dacfa50..f614e2dc98d8c 100644
--- a/lib/AST/TypeRepr.cpp
+++ b/lib/AST/TypeRepr.cpp
@@ -235,10 +235,10 @@ const TypeRepr *DeclRefTypeRepr::getRoot() const {
 DeclNameLoc DeclRefTypeRepr::getNameLoc() const { return NameLoc; }
 
 DeclNameRef DeclRefTypeRepr::getNameRef() const {
-  if (NameOrDecl.is<DeclNameRef>())
-    return NameOrDecl.get<DeclNameRef>();
+  if (isa<DeclNameRef>(NameOrDecl))
+    return cast<DeclNameRef>(NameOrDecl);
 
-  return NameOrDecl.get<TypeDecl *>()->createNameRef();
+  return cast<TypeDecl *>(NameOrDecl)->createNameRef();
 }
 
 void DeclRefTypeRepr::overwriteNameRef(DeclNameRef newId) {
@@ -246,7 +246,7 @@ void DeclRefTypeRepr::overwriteNameRef(DeclNameRef newId) {
   NameOrDecl = newId;
 }
 
-bool DeclRefTypeRepr::isBound() const { return NameOrDecl.is<TypeDecl *>(); }
+bool DeclRefTypeRepr::isBound() const { return isa<TypeDecl *>(NameOrDecl); }
 
 TypeDecl *DeclRefTypeRepr::getBoundDecl() const {
   return NameOrDecl.dyn_cast<TypeDecl *>();
@@ -319,19 +319,22 @@ InlineArrayTypeRepr *InlineArrayTypeRepr::create(ASTContext &ctx,
 }
 
 static void printTypeRepr(const TypeRepr *TyR, ASTPrinter &Printer,
-                          const PrintOptions &Opts) {
+                          const PrintOptions &Opts,
+                          NonRecursivePrintOptions nrOpts = std::nullopt) {
   if (TyR == nullptr)
     Printer << "<null>";
   else
-    TyR->print(Printer, Opts);
+    TyR->print(Printer, Opts, nrOpts);
 }
 
-void TypeRepr::print(raw_ostream &OS, const PrintOptions &Opts) const {
+void TypeRepr::print(raw_ostream &OS, const PrintOptions &opts,
+                     NonRecursivePrintOptions nrOpts) const {
   StreamPrinter Printer(OS);
-  print(Printer, Opts);
+  print(Printer, opts, nrOpts);
 }
 
-void TypeRepr::print(ASTPrinter &Printer, const PrintOptions &Opts) const {
+void TypeRepr::print(ASTPrinter &Printer, const PrintOptions &opts,
+                     NonRecursivePrintOptions nrOpts) const {
   Printer.printTypePre(TypeLoc(const_cast<TypeRepr *>(this)));
   SWIFT_DEFER {
     Printer.printTypePost(TypeLoc(const_cast<TypeRepr *>(this)));
@@ -341,7 +344,7 @@ void TypeRepr::print(ASTPrinter &Printer, const PrintOptions &Opts) const {
 #define TYPEREPR(CLASS, PARENT) \
   case TypeReprKind::CLASS: { \
     auto Ty = static_cast<const CLASS##TypeRepr*>(this); \
-    return Ty->printImpl(Printer, Opts); \
+    return Ty->printImpl(Printer, opts, nrOpts); \
   }
 #include "swift/AST/TypeReprNodes.def"
   }
@@ -349,7 +352,8 @@ void TypeRepr::print(ASTPrinter &Printer, const PrintOptions &Opts) const {
 }
 
 void ErrorTypeRepr::printImpl(ASTPrinter &Printer,
-                              const PrintOptions &Opts) const {
+                              const PrintOptions &opts,
+                              NonRecursivePrintOptions nrOpts) const {
   Printer << "<<error type>>";
 }
 
@@ -386,9 +390,13 @@ ReferenceOwnership AttributedTypeRepr::getSILOwnership() const {
 }
 
 void AttributedTypeRepr::printImpl(ASTPrinter &Printer,
-                                   const PrintOptions &Opts) const {
-  printAttrs(Printer, Opts);
-  printTypeRepr(Ty, Printer, Opts);
+                                   const PrintOptions &opts,
+                                   NonRecursivePrintOptions nrOpts) const {
+  printAttrs(Printer, opts);
+
+  // Consider the non-recursive options to still apply to the type
+  // modified by the attribute.
+  printTypeRepr(Ty, Printer, opts, nrOpts);
 }
 
 void AttributedTypeRepr::printAttrs(llvm::raw_ostream &OS) const {
@@ -402,10 +410,10 @@ void AttributedTypeRepr::printAttrs(ASTPrinter &Printer,
     if (auto customAttr = attr.dyn_cast<CustomAttr*>()) {
       Printer.callPrintStructurePre(PrintStructureKind::BuiltinAttribute);
       Printer << "@";
-      customAttr->getTypeRepr()->print(Printer, Options);
+      customAttr->getTypeRepr()->print(Printer, Options, std::nullopt);
       Printer.printStructurePost(PrintStructureKind::BuiltinAttribute);
     } else {
-      auto typeAttr = attr.get<TypeAttribute*>();
+      auto typeAttr = cast<TypeAttribute *>(attr);
       if (Options.excludeAttrKind(typeAttr->getKind()))
         continue;
       typeAttr->print(Printer, Options);
@@ -415,9 +423,10 @@ void AttributedTypeRepr::printAttrs(ASTPrinter &Printer,
 }
 
 void DeclRefTypeRepr::printImpl(ASTPrinter &Printer,
-                                const PrintOptions &Opts) const {
+                                const PrintOptions &opts,
+                                NonRecursivePrintOptions nrOpts) const {
   if (auto *qualIdentTR = dyn_cast<QualifiedIdentTypeRepr>(this)) {
-    printTypeRepr(qualIdentTR->getBase(), Printer, Opts);
+    printTypeRepr(qualIdentTR->getBase(), Printer, opts);
     Printer << ".";
   }
 
@@ -434,14 +443,15 @@ void DeclRefTypeRepr::printImpl(ASTPrinter &Printer,
     Printer << "<";
     interleave(
         getGenericArgs(),
-        [&](TypeRepr *Arg) { printTypeRepr(Arg, Printer, Opts); },
+        [&](TypeRepr *Arg) { printTypeRepr(Arg, Printer, opts); },
         [&] { Printer << ", "; });
     Printer << ">";
   }
 }
 
 void FunctionTypeRepr::printImpl(ASTPrinter &Printer,
-                                 const PrintOptions &Opts) const {
+                                 const PrintOptions &Opts,
+                                 NonRecursivePrintOptions nrOpts) const {
   Printer.callPrintStructurePre(PrintStructureKind::FunctionType);
   printTypeRepr(ArgsTy, Printer, Opts);
   if (isAsync()) {
@@ -462,42 +472,32 @@ void FunctionTypeRepr::printImpl(ASTPrinter &Printer,
   Printer << " -> ";
   Printer.callPrintStructurePre(PrintStructureKind::FunctionReturnType);
 
-  // Check if we are supposed to suppress sending results. If so, look through
-  // the ret ty if it is a Sending TypeRepr.
-  //
-  // DISCUSSION: The reason why we do this is that Sending TypeRepr is used for
-  // arguments and results... and we need the arguments case when we suppress to
-  // print __owned. So this lets us handle both cases.
-  auto ActualRetTy = RetTy;
-  if (Opts.SuppressSendingArgsAndResults) {
-    if (auto *x = dyn_cast<SendingTypeRepr>(RetTy)) {
-      ActualRetTy = x->getBase();
-    }
-  }
-  printTypeRepr(ActualRetTy, Printer, Opts);
-
+  printTypeRepr(RetTy, Printer, Opts);
   Printer.printStructurePost(PrintStructureKind::FunctionReturnType);
   Printer.printStructurePost(PrintStructureKind::FunctionType);
 }
 
 void InlineArrayTypeRepr::printImpl(ASTPrinter &Printer,
-                                    const PrintOptions &Opts) const {
+                                    const PrintOptions &Opts,
+                                    NonRecursivePrintOptions nrOpts) const {
   Printer << "[";
   printTypeRepr(getCount(), Printer, Opts);
-  Printer << " x ";
+  Printer << " of ";
   printTypeRepr(getElement(), Printer, Opts);
   Printer << "]";
 }
 
 void ArrayTypeRepr::printImpl(ASTPrinter &Printer,
-                              const PrintOptions &Opts) const {
+                              const PrintOptions &Opts,
+                              NonRecursivePrintOptions nrOpts) const {
   Printer << "[";
   printTypeRepr(getBase(), Printer, Opts);
   Printer << "]";
 }
 
 void DictionaryTypeRepr::printImpl(ASTPrinter &Printer,
-                                   const PrintOptions &Opts) const {
+                                   const PrintOptions &Opts,
+                                   NonRecursivePrintOptions nrOpts) const {
   Printer << "[";
   printTypeRepr(Key, Printer, Opts);
   Printer << " : ";
@@ -506,13 +506,15 @@ void DictionaryTypeRepr::printImpl(ASTPrinter &Printer,
 }
 
 void OptionalTypeRepr::printImpl(ASTPrinter &Printer,
-                                 const PrintOptions &Opts) const {
+                                 const PrintOptions &Opts,
+                                 NonRecursivePrintOptions nrOpts) const {
   printTypeRepr(Base, Printer, Opts);
   Printer << "?";
 }
 
 void ImplicitlyUnwrappedOptionalTypeRepr::printImpl(ASTPrinter &Printer,
-                                          const PrintOptions &Opts) const {
+                                 const PrintOptions &Opts,
+                                 NonRecursivePrintOptions nrOpts) const {
   printTypeRepr(Base, Printer, Opts);
   Printer << "!";
 }
@@ -523,7 +525,7 @@ TupleTypeRepr::TupleTypeRepr(ArrayRef<TupleTypeReprElement> Elements,
   Bits.TupleTypeRepr.NumElements = Elements.size();
 
   std::uninitialized_copy(Elements.begin(), Elements.end(),
-                          getTrailingObjects<TupleTypeReprElement>());
+                          getTrailingObjects());
 }
 
 TupleTypeRepr *TupleTypeRepr::create(const ASTContext &C,
@@ -680,7 +682,7 @@ PackTypeRepr::PackTypeRepr(SourceLoc keywordLoc, SourceRange braceLocs,
   : TypeRepr(TypeReprKind::Pack),
     KeywordLoc(keywordLoc), BraceLocs(braceLocs) {
   Bits.PackTypeRepr.NumElements = elements.size();
-  memcpy(getTrailingObjects<TypeRepr*>(), elements.data(),
+  memcpy(getTrailingObjects(), elements.data(),
          elements.size() * sizeof(TypeRepr*));
 }
 
@@ -743,20 +745,23 @@ SourceLoc LifetimeDependentTypeRepr::getLocImpl() const {
 }
 
 void LifetimeDependentTypeRepr::printImpl(ASTPrinter &Printer,
-                                          const PrintOptions &Opts) const {
+                                          const PrintOptions &Opts,
+                                          NonRecursivePrintOptions nrOpts) const {
   Printer << " ";
   Printer << getLifetimeEntry()->getString();
-  printTypeRepr(getBase(), Printer, Opts);
+  printTypeRepr(getBase(), Printer, Opts, nrOpts);
 }
 
 void VarargTypeRepr::printImpl(ASTPrinter &Printer,
-                               const PrintOptions &Opts) const {
+                               const PrintOptions &Opts,
+                               NonRecursivePrintOptions nrOpts) const {
   printTypeRepr(Element, Printer, Opts);
   Printer << "...";
 }
 
 void PackTypeRepr::printImpl(ASTPrinter &Printer,
-                             const PrintOptions &Opts) const {
+                             const PrintOptions &Opts,
+                             NonRecursivePrintOptions nrOpts) const {
   Printer.printKeyword("Pack", Opts);
   Printer << "{";
   auto elts = getElements();
@@ -768,19 +773,22 @@ void PackTypeRepr::printImpl(ASTPrinter &Printer,
 }
 
 void PackExpansionTypeRepr::printImpl(ASTPrinter &Printer,
-                                      const PrintOptions &Opts) const {
+                                      const PrintOptions &Opts,
+                                      NonRecursivePrintOptions nrOpts) const {
   Printer.printKeyword("repeat", Opts, /*Suffix=*/" ");
   printTypeRepr(Pattern, Printer, Opts);
 }
 
 void PackElementTypeRepr::printImpl(ASTPrinter &Printer,
-                                    const PrintOptions &Opts) const {
+                                    const PrintOptions &Opts,
+                                    NonRecursivePrintOptions nrOpts) const {
   Printer.printKeyword("each", Opts, /*Suffix=*/" ");
   printTypeRepr(PackType, Printer, Opts);
 }
 
 void TupleTypeRepr::printImpl(ASTPrinter &Printer,
-                              const PrintOptions &Opts) const {
+                              const PrintOptions &Opts,
+                              NonRecursivePrintOptions nrOpts) const {
   Printer.callPrintStructurePre(PrintStructureKind::TupleType);
   SWIFT_DEFER { Printer.printStructurePost(PrintStructureKind::TupleType); };
 
@@ -822,7 +830,8 @@ CompositionTypeRepr *CompositionTypeRepr::create(const ASTContext &C,
 }
 
 void CompositionTypeRepr::printImpl(ASTPrinter &Printer,
-                                    const PrintOptions &Opts) const {
+                                    const PrintOptions &Opts,
+                                    NonRecursivePrintOptions nrOpts) const {
   if (getTypes().empty()) {
     Printer.printKeyword("Any", Opts);
   } else {
@@ -832,25 +841,29 @@ void CompositionTypeRepr::printImpl(ASTPrinter &Printer,
 }
 
 void MetatypeTypeRepr::printImpl(ASTPrinter &Printer,
-                                 const PrintOptions &Opts) const {
+                                 const PrintOptions &Opts,
+                                 NonRecursivePrintOptions nrOpts) const {
   printTypeRepr(Base, Printer, Opts);
   Printer << ".Type";
 }
 
 void ProtocolTypeRepr::printImpl(ASTPrinter &Printer,
-                                 const PrintOptions &Opts) const {
+                                 const PrintOptions &Opts,
+                                 NonRecursivePrintOptions nrOpts) const {
   printTypeRepr(Base, Printer, Opts);
   Printer << ".Protocol";
 }
 
 void OpaqueReturnTypeRepr::printImpl(ASTPrinter &Printer,
-                                     const PrintOptions &Opts) const {
+                                     const PrintOptions &Opts,
+                                     NonRecursivePrintOptions nrOpts) const {
   Printer.printKeyword("some", Opts, /*Suffix=*/" ");
   printTypeRepr(Constraint, Printer, Opts);
 }
 
 void ExistentialTypeRepr::printImpl(ASTPrinter &Printer,
-                                    const PrintOptions &Opts) const {
+                                    const PrintOptions &Opts,
+                                    NonRecursivePrintOptions nrOpts) const {
   Printer.printKeyword("any", Opts, /*Suffix=*/" ");
   printTypeRepr(Constraint, Printer, Opts);
 }
@@ -868,20 +881,23 @@ SourceLoc NamedOpaqueReturnTypeRepr::getLocImpl() const {
 }
 
 void NamedOpaqueReturnTypeRepr::printImpl(ASTPrinter &Printer,
-                                          const PrintOptions &Opts) const {
+                                  const PrintOptions &Opts,
+                                  NonRecursivePrintOptions nrOpts) const {
   GenericParams->print(Printer, Opts);
   Printer << ' ';
   printTypeRepr(Base, Printer, Opts);
 }
 
 void InverseTypeRepr::printImpl(ASTPrinter &Printer,
-                                const PrintOptions &Opts) const {
+                                const PrintOptions &Opts,
+                                NonRecursivePrintOptions nrOpts) const {
   Printer << "~";
   printTypeRepr(Constraint, Printer, Opts);
 }
 
 void SpecifierTypeRepr::printImpl(ASTPrinter &Printer,
-                                  const PrintOptions &Opts) const {
+                                  const PrintOptions &Opts,
+                                  NonRecursivePrintOptions nrOpts) const {
   switch (getKind()) {
 #define TYPEREPR(CLASS, PARENT) case TypeReprKind::CLASS:
 #define SPECIFIER_TYPEREPR(CLASS, PARENT)
@@ -897,13 +913,7 @@ void SpecifierTypeRepr::printImpl(ASTPrinter &Printer,
     Printer.printKeyword("isolated", Opts, " ");
     break;
   case TypeReprKind::Sending:
-    // This handles the argument case. The result case is handled in
-    // FunctionTypeRepr.
-    if (!Opts.SuppressSendingArgsAndResults) {
-      Printer.printKeyword("sending", Opts, " ");
-    } else {
-      Printer.printKeyword("__owned", Opts, " ");
-    }
+    Printer.printKeyword("sending", Opts, " ");
     break;
   case TypeReprKind::CompileTimeLiteral:
     Printer.printKeyword("_const", Opts, " ");
@@ -912,7 +922,7 @@ void SpecifierTypeRepr::printImpl(ASTPrinter &Printer,
     Printer.printKeyword("@const", Opts, " ");
     break;
   }
-  printTypeRepr(Base, Printer, Opts);
+  printTypeRepr(Base, Printer, Opts, nrOpts);
 }
 
 StringRef OwnershipTypeRepr::getSpecifierSpelling() const {
@@ -923,41 +933,43 @@ ValueOwnership OwnershipTypeRepr::getValueOwnership() const {
   return ParamDecl::getValueOwnershipForSpecifier(getSpecifier());
 }
 
+void CallerIsolatedTypeRepr::printImpl(ASTPrinter &Printer,
+                                const PrintOptions &Opts,
+                                NonRecursivePrintOptions nrOpts) const {
+  Printer.printKeyword("nonisolated(nonsending)", Opts);
+}
+
 void PlaceholderTypeRepr::printImpl(ASTPrinter &Printer,
-                                    const PrintOptions &Opts) const {
+                                    const PrintOptions &Opts,
+                                    NonRecursivePrintOptions nrOpts) const {
   Printer.printText("_");
 }
 
 void FixedTypeRepr::printImpl(ASTPrinter &Printer,
-                              const PrintOptions &Opts) const {
-  getType().print(Printer, Opts);
+                              const PrintOptions &Opts,
+                              NonRecursivePrintOptions nrOpts) const {
+  getType().print(Printer, Opts, nrOpts);
 }
 
 void SelfTypeRepr::printImpl(ASTPrinter &Printer,
-                             const PrintOptions &Opts) const {
-  getType().print(Printer, Opts);
+                             const PrintOptions &Opts,
+                             NonRecursivePrintOptions nrOpts) const {
+  getType().print(Printer, Opts, nrOpts);
 }
 
 void SILBoxTypeRepr::printImpl(ASTPrinter &Printer,
-                               const PrintOptions &Opts) const {
+                               const PrintOptions &Opts,
+                               NonRecursivePrintOptions nrOpts) const {
   // TODO
   Printer.printKeyword("sil_box", Opts);
 }
 
 void IntegerTypeRepr::printImpl(ASTPrinter &Printer,
-                                const PrintOptions &Opts) const {
+                                const PrintOptions &Opts,
+                                NonRecursivePrintOptions nrOpts) const {
   Printer.printText(getValue());
 }
 
-void ErrorTypeRepr::dischargeDiagnostic(swift::ASTContext &Context) {
-  if (!DelayedDiag)
-    return;
-
-  // Consume and emit the diagnostic.
-  Context.Diags.diagnose(Range.Start, *DelayedDiag).highlight(Range);
-  DelayedDiag = std::nullopt;
-}
-
 // See swift/Basic/Statistic.h for declaration: this enables tracing
 // TypeReprs, is defined here to avoid too much layering violation / circular
 // linkage dependency.
diff --git a/lib/AST/TypeSubstitution.cpp b/lib/AST/TypeSubstitution.cpp
index 723998f992c65..3eaf3cd55e5ab 100644
--- a/lib/AST/TypeSubstitution.cpp
+++ b/lib/AST/TypeSubstitution.cpp
@@ -75,16 +75,29 @@ CanGenericFunctionType::substGenericArgs(SubstitutionMap subs) const {
 }
 
 ProtocolConformanceRef LookUpConformanceInModule::
-operator()(CanType dependentType, Type conformingReplacementType,
+operator()(InFlightSubstitution &IFS, Type dependentType,
            ProtocolDecl *conformedProtocol) const {
-  return lookupConformance(conformingReplacementType,
+  return lookupConformance(dependentType.subst(IFS),
                            conformedProtocol,
                            /*allowMissing=*/true);
 }
 
 ProtocolConformanceRef LookUpConformanceInSubstitutionMap::
-operator()(CanType dependentType, Type conformingReplacementType,
+operator()(InFlightSubstitution &IFS, Type dependentType,
            ProtocolDecl *conformedProtocol) const {
+  if (dependentType->is<PrimaryArchetypeType>() ||
+      dependentType->is<PackArchetypeType>())
+    dependentType = dependentType->mapTypeOutOfContext();
+
+  auto result = Subs.lookupConformance(
+      dependentType->getCanonicalType(),
+      conformedProtocol);
+  if (!result.isInvalid())
+    return result;
+
+  // Don't compute this in the fast path above.
+  auto conformingReplacementType = dependentType.subst(IFS);
+
   // Lookup conformances for archetypes that conform concretely
   // via a superclass.
   if (conformingReplacementType->is<ArchetypeType>()) {
@@ -93,14 +106,6 @@ operator()(CanType dependentType, Type conformingReplacementType,
         /*allowMissing=*/true);
   }
 
-  if (isa<PrimaryArchetypeType>(dependentType) ||
-      isa<PackArchetypeType>(dependentType))
-    dependentType = dependentType->mapTypeOutOfContext()->getCanonicalType();
-
-  auto result = Subs.lookupConformance(dependentType, conformedProtocol);
-  if (!result.isInvalid())
-    return result;
-
   // Otherwise, the original type might be fixed to a concrete type in
   // the substitution map's input generic signature.
   if (auto genericSig = Subs.getGenericSignature()) {
@@ -115,48 +120,18 @@ operator()(CanType dependentType, Type conformingReplacementType,
   return ProtocolConformanceRef::forInvalid();
 }
 
-ProtocolConformanceRef MakeAbstractConformanceForGenericType::
-operator()(CanType dependentType, Type conformingReplacementType,
-           ProtocolDecl *conformedProtocol) const {
-  // The places that use this can also produce conformance packs, generally
-  // just for singleton pack expansions.
-  if (auto conformingPack = conformingReplacementType->getAs<PackType>()) {
-    SmallVector<ProtocolConformanceRef, 4> conformances;
-    for (auto conformingPackElt : conformingPack->getElementTypes()) {
-      // Look through pack expansions; there's no equivalent conformance
-      // expansion right now.
-      auto expansion = conformingPackElt->getAs<PackExpansionType>();
-      if (expansion) conformingPackElt = expansion->getPatternType();
-
-      auto conformance =
-        (*this)(dependentType, conformingPackElt, conformedProtocol);
-      conformances.push_back(conformance);
-    }
-    return ProtocolConformanceRef(
-        PackConformance::get(conformingPack, conformedProtocol, conformances));
-  }
-
-  if (conformingReplacementType->is<ErrorType>())
-    return ProtocolConformanceRef::forInvalid();
-
-  // A class-constrained archetype might conform to the protocol
-  // concretely.
-  if (auto *archetypeType = conformingReplacementType->getAs<ArchetypeType>()) {
-    if (archetypeType->getSuperclass()) {
-      return lookupConformance(archetypeType, conformedProtocol);
-    }
-  }
-
-  return ProtocolConformanceRef::forAbstract(
-    conformingReplacementType, conformedProtocol);
-}
-
 InFlightSubstitution::InFlightSubstitution(TypeSubstitutionFn substType,
                                            LookupConformanceFn lookupConformance,
                                            SubstOptions options)
-  : Options(options),
-    BaselineSubstType(substType),
-    BaselineLookupConformance(lookupConformance) {
+  : BaselineSubstType(substType),
+    BaselineLookupConformance(lookupConformance),
+    Options(options) {
+
+  InitLimit = 0;
+  LimitReached = 0;
+  RemainingDepth = 0;
+  RemainingCount = 0;
+
   // FIXME: Don't substitute type parameters if one of the special flags is set.
   Props |= RecursiveTypeProperties::HasTypeParameter;
 
@@ -216,22 +191,14 @@ void InFlightSubstitution::expandPackExpansionShape(Type origShape,
   ActivePackExpansions.pop_back();
 }
 
-Type InFlightSubstitution::substType(SubstitutableType *origType,
-                                     unsigned level) {
-  auto substType = BaselineSubstType(origType);
-  if (!substType)
-    return Type();
+Type InFlightSubstitution::projectLaneFromPackType(Type substType,
+                                                   unsigned level) {
+  auto outerExpansions = ArrayRef(ActivePackExpansions).drop_back(level);
+  auto innerExpansions = ArrayRef(ActivePackExpansions).take_back(level);
 
   // FIXME: All the logic around 'level' is probably slightly wrong, and in
   // the unlikely event that it is correct, at the very least warrants a
   // detailed explanation.
-
-  if (ActivePackExpansions.empty())
-    return substType->increasePackElementLevel(level);
-
-  auto outerExpansions = ArrayRef(ActivePackExpansions).drop_back(level);
-  auto innerExpansions = ArrayRef(ActivePackExpansions).take_back(level);
-
   unsigned outerLevel = 0;
   if (!getOptions().contains(SubstFlags::PreservePackExpansionLevel)) {
     for (const auto &activeExpansion : outerExpansions) {
@@ -272,20 +239,56 @@ Type InFlightSubstitution::substType(SubstitutableType *origType,
   }
 }
 
+/// Note that the type is just used to recover an ASTContext.
+bool InFlightSubstitution::checkLimits(Type ty) {
+  if (!InitLimit) {
+    auto &ctx = ty->getASTContext();
+
+    InitLimit = 1;
+    RemainingCount = ctx.LangOpts.MaxSubstitutionCount;
+    RemainingDepth = ctx.LangOpts.MaxSubstitutionDepth;
+    return false;
+  }
+
+  if (RemainingCount == 0 || RemainingDepth == 0) {
+    LimitReached = true;
+    return true;
+  }
+  return false;
+}
+
+Type InFlightSubstitution::substType(SubstitutableType *origType,
+                                     unsigned level) {
+  auto substType = BaselineSubstType(origType);
+  if (!substType)
+    return Type();
+
+  if (!ActivePackExpansions.empty())
+    substType = projectLaneFromPackType(substType, level);
+  else
+    substType = substType->increasePackElementLevel(level);
+
+  // Opaque type replacement must iterate until fixed point.
+  if (shouldSubstituteOpaqueArchetypes() &&
+      substType->hasOpaqueArchetype() &&
+      !substType->isEqual(origType)) {
+    if (checkLimits(origType)) {
+      return ErrorType::get(substType);
+    }
+
+    --RemainingCount;
+    --RemainingDepth;
+    substType = substType.subst(*this);
+    ++RemainingDepth;
+  }
+
+  return substType;
+}
+
 ProtocolConformanceRef
-InFlightSubstitution::lookupConformance(CanType dependentType,
-                                        Type conformingReplacementType,
-                                        ProtocolDecl *conformedProtocol,
-                                        unsigned level) {
-  auto substConfRef = BaselineLookupConformance(dependentType,
-                                                conformingReplacementType,
-                                                conformedProtocol);
-  if (!substConfRef ||
-      ActivePackExpansions.empty() ||
-      !substConfRef.isPack())
-    return substConfRef;
-
-  auto substPackConf = substConfRef.getPack();
+InFlightSubstitution::projectLaneFromPackConformance(
+                                                 PackConformance *substPackConf,
+                                                 unsigned level) {
   auto substPackPatterns = substPackConf->getPatternConformances();
   assert(level < ActivePackExpansions.size() && "too deep");
   auto index = ActivePackExpansions[ActivePackExpansions.size() - level - 1]
@@ -296,6 +299,32 @@ InFlightSubstitution::lookupConformance(CanType dependentType,
   return substPackPatterns[index];
 }
 
+ProtocolConformanceRef
+InFlightSubstitution::lookupConformance(Type dependentType,
+                                        ProtocolDecl *proto,
+                                        unsigned level) {
+  auto substConfRef = BaselineLookupConformance(*this, dependentType, proto);
+  if (!ActivePackExpansions.empty() && substConfRef.isPack()) {
+    substConfRef = projectLaneFromPackConformance(
+        substConfRef.getPack(), level);
+  }
+
+  // Opaque type replacement must iterate until fixed point.
+  if (shouldSubstituteOpaqueArchetypes() && substConfRef &&
+      substConfRef.getType()->hasOpaqueArchetype() &&
+      !substConfRef.getType()->isEqual(dependentType)) {
+    if (checkLimits(dependentType)) {
+      return ProtocolConformanceRef::forInvalid();
+    }
+    --RemainingCount;
+    --RemainingDepth;
+    substConfRef = substConfRef.subst(*this);
+    ++RemainingDepth;
+  }
+
+  return substConfRef;
+}
+
 namespace {
 
 class TypeSubstituter : public TypeTransform<TypeSubstituter> {
@@ -378,7 +407,7 @@ TypeSubstituter::transformOpaqueTypeArchetypeType(OpaqueTypeArchetypeType *opaqu
 
   // If we return an opaque archetype unchanged, recurse into its substitutions
   // as a special case.
-  if (known->getCanonicalType() == opaque->getCanonicalType())
+  if (known.getPointer() == opaque)
     return std::nullopt; // Recursively process the substitutions of the
                          // opaque type archetype.
   return known;
@@ -430,20 +459,19 @@ Type TypeSubstituter::transformPackElementType(PackElementType *element,
 Type TypeSubstituter::transformDependentMemberType(DependentMemberType *dependent,
                                                    TypePosition pos) {
   auto origBase = dependent->getBase();
-  auto substBase = doIt(origBase, TypePosition::Invariant);
-
-  if (auto *selfType = substBase->getAs<DynamicSelfType>())
-    substBase = selfType->getSelfType();
 
   auto *assocType = dependent->getAssocType();
   ASSERT(assocType);
 
-  auto proto = assocType->getProtocol();
-  ProtocolConformanceRef conformance =
-    IFS.lookupConformance(origBase->getCanonicalType(), substBase,
-                          proto, level);
+  auto *proto = assocType->getProtocol();
+  auto conformance = IFS.lookupConformance(origBase, proto, level);
 
-  return conformance.getTypeWitness(substBase, assocType, IFS.getOptions());
+  auto result = conformance.getTypeWitness(assocType, IFS.getOptions());
+  if (result->is<ErrorType>()) {
+    auto substBase = origBase.subst(IFS);
+    return DependentMemberType::get(ErrorType::get(substBase), assocType);
+  }
+  return result;
 }
 
 SubstitutionMap TypeSubstituter::transformSubstitutionMap(SubstitutionMap subs) {
@@ -514,14 +542,20 @@ Type TypeBase::getSuperclassForDecl(const ClassDecl *baseClass,
     t = t->getSuperclass(useArchetypes);
   }
 
-#ifndef NDEBUG
-  auto *currentClass = getConcreteTypeForSuperclassTraversing(this)
-      ->getClassOrBoundGenericClass();
-  assert(baseClass->isSuperclassOf(currentClass) &&
-         "no inheritance relationship between given classes");
-#endif
+  if (CONDITIONAL_ASSERT_enabled()) {
+    auto *currentClass = getConcreteTypeForSuperclassTraversing(this)
+        ->getClassOrBoundGenericClass();
+    ASSERT(baseClass->isSuperclassOf(currentClass) &&
+           "no inheritance relationship between given classes");
+  }
 
-  return ErrorType::get(this);
+  // We can end up here if the AST is invalid, because then
+  // getSuperclassDecl() might resolve to a decl, and yet
+  // getSuperclass() is just an ErrorType. Make sure we still
+  // return a nominal type as the result though, and not an
+  // ErrorType, because that's what callers expect.
+  return baseClass->getDeclaredInterfaceType()
+      .subst(SubstitutionMap())->getCanonicalType();
 }
 
 SubstitutionMap TypeBase::getContextSubstitutionMap() {
@@ -537,7 +571,7 @@ SubstitutionMap TypeBase::getContextSubstitutionMap() {
 
   Type baseTy(this);
 
-  assert(!baseTy->hasLValueType() &&
+  assert(!baseTy->is<LValueType>() &&
          !baseTy->is<AnyMetatypeType>() &&
          !baseTy->is<ErrorType>());
 
@@ -619,7 +653,7 @@ TypeBase::getContextSubstitutions(const DeclContext *dc,
   assert(dc->isTypeContext());
   Type baseTy(this);
 
-  assert(!baseTy->hasLValueType() &&
+  assert(!baseTy->is<LValueType>() &&
          !baseTy->is<AnyMetatypeType>() &&
          !baseTy->is<ErrorType>());
 
@@ -744,7 +778,9 @@ TypeBase::getContextSubstitutions(const DeclContext *dc,
 SubstitutionMap TypeBase::getContextSubstitutionMap(
     const DeclContext *dc,
     GenericEnvironment *genericEnv) {
-  if (dc == getAnyNominal() && genericEnv == nullptr)
+  auto *nominal = getAnyNominal();
+  if (dc == nominal && !isa<ProtocolDecl>(nominal) &&
+      genericEnv == nullptr)
     return getContextSubstitutionMap();
 
   auto genericSig = dc->getGenericSignatureOfContext();
@@ -831,33 +867,27 @@ Type TypeBase::getTypeOfMember(const ValueDecl *member,
 
 Type TypeBase::adjustSuperclassMemberDeclType(const ValueDecl *baseDecl,
                                               const ValueDecl *derivedDecl,
-                                              Type memberType) {
+                                              Type type) {
   auto subs = SubstitutionMap::getOverrideSubstitutions(
       baseDecl, derivedDecl);
 
-  if (auto *genericMemberType = memberType->getAs<GenericFunctionType>()) {
-    memberType = FunctionType::get(genericMemberType->getParams(),
-                                   genericMemberType->getResult(),
-                                   genericMemberType->getExtInfo());
+  if (auto *genericMemberType = type->getAs<GenericFunctionType>()) {
+    type = genericMemberType->substGenericArgs(subs);
+  } else {
+    type = type.subst(subs);
   }
 
-  auto type = memberType.subst(subs);
   if (baseDecl->getDeclContext()->getSelfProtocolDecl())
     return type;
 
   if (auto *afd = dyn_cast<AbstractFunctionDecl>(baseDecl)) {
     type = type->replaceSelfParameterType(this);
-    if (afd->hasDynamicSelfResult())
-      type = type->replaceCovariantResultType(this, /*uncurryLevel=*/2);
-  } else if (auto *sd = dyn_cast<SubscriptDecl>(baseDecl)) {
-    if (sd->getElementInterfaceType()->hasDynamicSelfType())
-      type = type->replaceCovariantResultType(this, /*uncurryLevel=*/1);
-  } else if (auto *vd = dyn_cast<VarDecl>(baseDecl)) {
-    if (vd->getValueInterfaceType()->hasDynamicSelfType())
-      type = type->replaceCovariantResultType(this, /*uncurryLevel=*/0);
+    if (isa<ConstructorDecl>(afd) &&
+        afd->getDeclContext()->getSelfClassDecl())
+      type = type->withCovariantResultType();
   }
 
-  return type;
+  return type->replaceDynamicSelfType(this);
 }
 
 //===----------------------------------------------------------------------===//
@@ -867,10 +897,10 @@ Type TypeBase::adjustSuperclassMemberDeclType(const ValueDecl *baseDecl,
 OpaqueSubstitutionKind
 ReplaceOpaqueTypesWithUnderlyingTypes::shouldPerformSubstitution(
     OpaqueTypeDecl *opaque) const {
-  const auto *inContext = getContext();
   auto inModule = inContext ? inContext->getParentModule()
                             : opaque->getParentModule();
-  return shouldPerformSubstitution(opaque, inModule, contextExpansion);
+  return shouldPerformSubstitution(
+      opaque, inModule, ResilienceExpansion(contextExpansion));
 }
 OpaqueSubstitutionKind
 ReplaceOpaqueTypesWithUnderlyingTypes::shouldPerformSubstitution(
@@ -918,17 +948,6 @@ ReplaceOpaqueTypesWithUnderlyingTypes::shouldPerformSubstitution(
   return OpaqueSubstitutionKind::SubstituteNonResilientModule;
 }
 
-static Type substOpaqueTypesWithUnderlyingTypesRec(
-    Type ty, const DeclContext *inContext, ResilienceExpansion contextExpansion,
-    bool isWholeModuleContext,
-    llvm::DenseSet<ReplaceOpaqueTypesWithUnderlyingTypes::SeenDecl> &decls) {
-  ReplaceOpaqueTypesWithUnderlyingTypes replacer(inContext, contextExpansion,
-                                                 isWholeModuleContext, decls);
-  return ty.subst(replacer, replacer,
-                  SubstFlags::SubstituteOpaqueArchetypes |
-                  SubstFlags::PreservePackExpansionLevel);
-}
-
 /// Checks that \p dc has access to \p ty for the purposes of an opaque
 /// substitution described by \p kind.
 ///
@@ -985,13 +1004,6 @@ static bool canSubstituteTypeInto(Type ty, const DeclContext *dc,
   llvm_unreachable("invalid substitution kind");
 }
 
-ReplaceOpaqueTypesWithUnderlyingTypes::ReplaceOpaqueTypesWithUnderlyingTypes(
-    const DeclContext *inContext, ResilienceExpansion contextExpansion,
-    bool isWholeModuleContext, llvm::DenseSet<SeenDecl> &seen)
-    : contextExpansion(contextExpansion),
-      inContextAndIsWholeModule(inContext, isWholeModuleContext),
-      seenDecls(&seen) {}
-
 Type ReplaceOpaqueTypesWithUnderlyingTypes::
 operator()(SubstitutableType *maybeOpaqueType) const {
   auto *archetype = dyn_cast<OpaqueTypeArchetypeType>(maybeOpaqueType);
@@ -1007,7 +1019,7 @@ operator()(SubstitutableType *maybeOpaqueType) const {
     return maybeOpaqueType;
   }
 
-  auto subs = decl->getUniqueUnderlyingTypeSubstitutions();
+  auto subs = decl->getUniqueUnderlyingTypeSubstitutions(typeCheckFunctionBodies);
   // If the body of the opaque decl providing decl has not been type checked we
   // don't have a underlying substitution.
   if (!subs.has_value())
@@ -1020,16 +1032,12 @@ operator()(SubstitutableType *maybeOpaqueType) const {
 
   // Check that we are allowed to substitute the underlying type into the
   // context.
-  auto inContext = this->getContext();
-  auto isContextWholeModule = this->isWholeModule();
-  auto contextExpansion = this->contextExpansion;
   if (inContext &&
       partialSubstTy.findIf(
-          [inContext, substitutionKind, isContextWholeModule,
-           contextExpansion](Type t) -> bool {
+          [&](Type t) -> bool {
             if (!canSubstituteTypeInto(t, inContext, substitutionKind,
-                                       contextExpansion,
-                                       isContextWholeModule))
+                                       ResilienceExpansion(contextExpansion),
+                                       isWholeModule))
               return true;
             return false;
           }))
@@ -1039,40 +1047,11 @@ operator()(SubstitutableType *maybeOpaqueType) const {
   // for its type arguments. We perform this substitution after checking for
   // visibility, since we do not want the result of the visibility check to
   // depend on the substitutions previously applied.
-  auto substTy = partialSubstTy.subst(outerSubs);
-
-  // If the type changed, but still contains opaque types, recur.
-  if (!substTy->isEqual(maybeOpaqueType) && substTy->hasOpaqueArchetype()) {
-    SeenDecl seenKey(decl, outerSubs);
-    if (auto *alreadySeen = this->seenDecls) {
-      // Detect substitution loops. If we find one, just bounce the original
-      // type back to the caller. This substitution will fail at runtime
-      // instead.
-      if (!alreadySeen->insert(seenKey).second) {
-        return maybeOpaqueType;
-      }
-
-      auto res = ::substOpaqueTypesWithUnderlyingTypesRec(
-          substTy, inContext, contextExpansion, isContextWholeModule,
-          *alreadySeen);
-      alreadySeen->erase(seenKey);
-      return res;
-    } else {
-      // We're the top of the stack for the recursion check. Allocate a set of
-      // opaque result type decls we've already seen for the rest of the check.
-      llvm::DenseSet<SeenDecl> seenDecls;
-      seenDecls.insert(seenKey);
-      return ::substOpaqueTypesWithUnderlyingTypesRec(
-          substTy, inContext, contextExpansion, isContextWholeModule,
-          seenDecls);
-    }
-  }
-
-  return substTy;
+  return partialSubstTy.subst(outerSubs);
 }
 
-CanType swift::substOpaqueTypesWithUnderlyingTypes(CanType ty,
-                                                   TypeExpansionContext context) {
+Type swift::substOpaqueTypesWithUnderlyingTypes(Type ty,
+                                                TypeExpansionContext context) {
   if (!context.shouldLookThroughOpaqueTypeArchetypes() ||
       !ty->hasOpaqueArchetype())
     return ty;
@@ -1080,51 +1059,83 @@ CanType swift::substOpaqueTypesWithUnderlyingTypes(CanType ty,
   ReplaceOpaqueTypesWithUnderlyingTypes replacer(
       context.getContext(), context.getResilienceExpansion(),
       context.isWholeModuleContext());
-  SubstOptions flags = (SubstFlags::SubstituteOpaqueArchetypes |
-                        SubstFlags::PreservePackExpansionLevel);
-  return ty.subst(replacer, replacer, flags)->getCanonicalType();
+  InFlightSubstitution IFS(replacer, replacer,
+                           SubstFlags::SubstituteOpaqueArchetypes |
+                           SubstFlags::PreservePackExpansionLevel);
+
+  auto substTy = ty.subst(IFS);
+
+  // FIXME: This should be a diagnostic at the source location of the innermost
+  // request or something.
+  if (IFS.wasLimitReached()) {
+    ABORT([&](auto &out) {
+      out << "Possible non-terminating type substitution detected\n\n";
+      out << "Original type:\n";
+      ty.dump(out);
+      out << "Substituted type:\n";
+      substTy.dump(out);
+    });
+  }
+
+  return substTy;
 }
 
-static ProtocolConformanceRef substOpaqueTypesWithUnderlyingTypesRec(
-    ProtocolConformanceRef ref, Type origType, const DeclContext *inContext,
-    ResilienceExpansion contextExpansion, bool isWholeModuleContext,
-    llvm::DenseSet<ReplaceOpaqueTypesWithUnderlyingTypes::SeenDecl> &decls) {
-  ReplaceOpaqueTypesWithUnderlyingTypes replacer(inContext, contextExpansion,
-                                                 isWholeModuleContext, decls);
-  return ref.subst(origType, replacer, replacer,
-                   SubstFlags::SubstituteOpaqueArchetypes |
-                   SubstFlags::PreservePackExpansionLevel);
+CanType
+swift::substOpaqueTypesWithUnderlyingTypes(CanType ty,
+                                           TypeExpansionContext context) {
+  return substOpaqueTypesWithUnderlyingTypes(static_cast<Type>(ty), context)
+      ->getCanonicalType();
 }
 
 ProtocolConformanceRef swift::substOpaqueTypesWithUnderlyingTypes(
-    ProtocolConformanceRef ref, Type origType, TypeExpansionContext context) {
+    ProtocolConformanceRef ref, TypeExpansionContext context) {
   ReplaceOpaqueTypesWithUnderlyingTypes replacer(
       context.getContext(), context.getResilienceExpansion(),
       context.isWholeModuleContext());
-  return ref.subst(origType, replacer, replacer,
-                   SubstFlags::SubstituteOpaqueArchetypes);
+  InFlightSubstitution IFS(replacer, replacer,
+                           SubstFlags::SubstituteOpaqueArchetypes);
+
+  auto substRef = ref.subst(IFS);
+
+  // FIXME: This should be a diagnostic at the source location of the innermost
+  // request or something.
+  if (IFS.wasLimitReached()) {
+    ABORT([&](auto &out) {
+      out << "Possible non-terminating conformance substitution detected\n\n";
+      out << "Original conformance:\n";
+      ref.dump(out);
+      out << "\nSubstituted conformance:\n";
+      substRef.dump(out);
+    });
+  }
+
+  return substRef;
 }
 
 ProtocolConformanceRef ReplaceOpaqueTypesWithUnderlyingTypes::
-operator()(CanType maybeOpaqueType, Type replacementType,
+operator()(InFlightSubstitution &IFS, Type maybeOpaqueType,
            ProtocolDecl *protocol) const {
   auto archetype = dyn_cast<OpaqueTypeArchetypeType>(maybeOpaqueType);
   if (!archetype)
-    return lookupConformance(replacementType, protocol);
+    return ProtocolConformanceRef::forAbstract(maybeOpaqueType, protocol);
 
   auto *genericEnv = archetype->getGenericEnvironment();
   auto *decl = genericEnv->getOpaqueTypeDecl();
   auto outerSubs = genericEnv->getOuterSubstitutions();
 
   auto substitutionKind = shouldPerformSubstitution(decl);
-  if (substitutionKind == OpaqueSubstitutionKind::DontSubstitute)
-    return lookupConformance(replacementType, protocol);
+  if (substitutionKind == OpaqueSubstitutionKind::DontSubstitute) {
+    return ProtocolConformanceRef::forAbstract(
+      maybeOpaqueType.subst(IFS), protocol);
+  }
 
   auto subs = decl->getUniqueUnderlyingTypeSubstitutions();
   // If the body of the opaque decl providing decl has not been type checked we
   // don't have a underlying substitution.
-  if (!subs.has_value())
-    return lookupConformance(replacementType, protocol);
+  if (!subs.has_value()) {
+    return ProtocolConformanceRef::forAbstract(
+      maybeOpaqueType.subst(IFS), protocol);
+  }
 
   // Apply the underlying type substitutions to the interface type of the
   // archetype in question. This will map the inner generic signature of the
@@ -1133,58 +1144,53 @@ operator()(CanType maybeOpaqueType, Type replacementType,
 
   // Check that we are allowed to substitute the underlying type into the
   // context.
-  auto inContext = this->getContext();
-  auto isContextWholeModule = this->isWholeModule();
-  auto contextExpansion = this->contextExpansion;
-  if (partialSubstTy.findIf(
-          [inContext, substitutionKind, isContextWholeModule,
-          contextExpansion](Type t) -> bool {
+  if (inContext &&
+      partialSubstTy.findIf(
+          [&](Type t) -> bool {
             if (!canSubstituteTypeInto(t, inContext, substitutionKind,
-                                       contextExpansion,
-                                       isContextWholeModule))
+                                       ResilienceExpansion(contextExpansion),
+                                       isWholeModule))
               return true;
             return false;
-          }))
-    return lookupConformance(replacementType, protocol);
-
-  // Then apply the substitutions from the root opaque archetype, to specialize
-  // for its type arguments. We perform this substitution after checking for
-  // visibility, since we do not want the result of the visibility check to
-  // depend on the substitutions previously applied.
-  auto substTy = partialSubstTy.subst(outerSubs);
+          })) {
+    return ProtocolConformanceRef::forAbstract(
+      maybeOpaqueType.subst(IFS), protocol);
+  }
 
   auto partialSubstRef =
       subs->lookupConformance(archetype->getInterfaceType()->getCanonicalType(),
                               protocol);
-  auto substRef =
-      partialSubstRef.subst(partialSubstTy, outerSubs);
-
-  // If the type still contains opaque types, recur.
-  if (substTy->hasOpaqueArchetype()) {
-    SeenDecl seenKey(decl, outerSubs);
-    
-    if (auto *alreadySeen = this->seenDecls) {
-      // Detect substitution loops. If we find one, just bounce the original
-      // type back to the caller. This substitution will fail at runtime
-      // instead.
-      if (!alreadySeen->insert(seenKey).second) {
-        return lookupConformance(replacementType, protocol);
-      }
+  return partialSubstRef.subst(outerSubs);
+}
 
-      auto res = ::substOpaqueTypesWithUnderlyingTypesRec(
-          substRef, substTy, inContext, contextExpansion, isContextWholeModule,
-          *alreadySeen);
-      alreadySeen->erase(seenKey);
-      return res;
-    } else {
-      // We're the top of the stack for the recursion check. Allocate a set of
-      // opaque result type decls we've already seen for the rest of the check.
-      llvm::DenseSet<SeenDecl> seenDecls;
-      seenDecls.insert(seenKey);
-      return ::substOpaqueTypesWithUnderlyingTypesRec(
-          substRef, substTy, inContext, contextExpansion, isContextWholeModule,
-          seenDecls);
-    }
-  }
-  return substRef;
+Type ReplaceExistentialArchetypesWithConcreteTypes::getInterfaceType(
+    ExistentialArchetypeType *type) const {
+  return type->getInterfaceType().transformRec(
+    [&](TypeBase *type) -> std::optional<Type> {
+      if (isa<GenericTypeParamType>(type))
+        return type->getASTContext().TheSelfType;
+      return std::nullopt;
+    });
+}
+
+Type ReplaceExistentialArchetypesWithConcreteTypes::operator()(
+    SubstitutableType *type) const {
+  auto *existentialArchetype = dyn_cast<ExistentialArchetypeType>(type);
+  if (!existentialArchetype ||
+      existentialArchetype->getGenericEnvironment() != env)
+    return type;
+
+  auto interfaceType = getInterfaceType(existentialArchetype);
+  return interfaceType.subst(subs);
+}
+
+ProtocolConformanceRef ReplaceExistentialArchetypesWithConcreteTypes::operator()(
+    InFlightSubstitution &IFS, Type origType, ProtocolDecl *proto) const {
+  auto existentialArchetype = dyn_cast<ExistentialArchetypeType>(origType);
+  if (!existentialArchetype ||
+      existentialArchetype->getGenericEnvironment() != env)
+    return ProtocolConformanceRef::forAbstract(origType.subst(IFS), proto);
+
+  return subs.lookupConformance(
+      getInterfaceType(existentialArchetype)->getCanonicalType(), proto);
 }
diff --git a/lib/AST/TypeWalker.cpp b/lib/AST/TypeWalker.cpp
index 9954fab3ca653..b14330d807a2c 100644
--- a/lib/AST/TypeWalker.cpp
+++ b/lib/AST/TypeWalker.cpp
@@ -35,7 +35,6 @@ class Traversal : public TypeVisitor<Traversal, bool>
   TypeWalker &Walker;
 
   bool visitErrorType(ErrorType *ty) { return false; }
-  bool visitUnresolvedType(UnresolvedType *ty) { return false; }
   bool visitPlaceholderType(PlaceholderType *ty) { return false; }
   bool visitBuiltinType(BuiltinType *ty) { return false; }
   bool visitIntegerType(IntegerType *ty) { return false; }
diff --git a/lib/AST/USRGeneration.cpp b/lib/AST/USRGeneration.cpp
index 077dd13e767af..fd25bc3db6909 100644
--- a/lib/AST/USRGeneration.cpp
+++ b/lib/AST/USRGeneration.cpp
@@ -173,7 +173,80 @@ static bool shouldUseObjCUSR(const Decl *D) {
 void swift::simple_display(llvm::raw_ostream &out,
                            const USRGenerationOptions &options) {
   out << "USRGenerationOptions (distinguishSynthesizedDecls: "
-      << options.distinguishSynthesizedDecls << ")";
+      << options.distinguishSynthesizedDecls
+      << ", useSwiftUSR: " << options.useSwiftUSR << ")";
+}
+
+std::optional<std::string>
+swift::ClangUSRGenerationRequest::evaluate(Evaluator &evaluator,
+                                           const ValueDecl *D) const {
+  llvm::SmallString<128> Buffer;
+  llvm::raw_svector_ostream OS(Buffer);
+
+  auto *importer = D->getASTContext().getClangModuleLoader();
+  if (ClangNode ClangN = importer->getEffectiveClangNode(D)) {
+    if (auto ClangD = ClangN.getAsDecl()) {
+      bool Ignore = clang::index::generateUSRForDecl(ClangD, Buffer);
+      if (!Ignore) {
+        return std::string(Buffer.str());
+      } else {
+        return std::string();
+      }
+    }
+
+    auto &Importer = *D->getASTContext().getClangModuleLoader();
+
+    auto ClangMacroInfo = ClangN.getAsMacro();
+    bool Ignore = clang::index::generateUSRForMacro(
+        D->getBaseIdentifier().str(), ClangMacroInfo->getDefinitionLoc(),
+        Importer.getClangASTContext().getSourceManager(), Buffer);
+    if (!Ignore)
+      return std::string(Buffer.str());
+    else
+      return std::string();
+  }
+
+  if (shouldUseObjCUSR(D)) {
+    if (printObjCUSR(D, OS)) {
+      return std::string();
+    } else {
+      return std::string(OS.str());
+    }
+  }
+
+  return std::nullopt;
+}
+
+std::optional<std::optional<std::string>>
+swift::ClangUSRGenerationRequest::getCachedResult() const {
+  auto *decl = std::get<0>(getStorage());
+  if (decl->LazySemanticInfo.noClangUSR)
+    return std::optional(std::optional<std::string>());
+
+  return decl->getASTContext().evaluator.getCachedNonEmptyOutput(*this);
+}
+
+void swift::ClangUSRGenerationRequest::cacheResult(
+    std::optional<std::string> result) const {
+  auto *decl = std::get<0>(getStorage());
+  if (!result) {
+    const_cast<ValueDecl *>(decl)->LazySemanticInfo.noClangUSR = 1;
+    return;
+  }
+  decl->getASTContext().evaluator.cacheNonEmptyOutput(*this, std::move(result));
+}
+
+std::string
+swift::SwiftUSRGenerationRequest::evaluate(Evaluator &evaluator,
+                                           const ValueDecl *D) const {
+  auto declIFaceTy = D->getInterfaceType();
+
+  // Invalid code.
+  if (declIFaceTy.findIf([](Type t) -> bool { return t->is<ModuleType>(); }))
+    return std::string();
+
+  Mangle::ASTMangler NewMangler(D->getASTContext());
+  return NewMangler.mangleDeclAsUSR(D, getUSRSpacePrefix());
 }
 
 std::string
@@ -184,13 +257,14 @@ swift::USRGenerationRequest::evaluate(Evaluator &evaluator, const ValueDecl *D,
 
   if (!D->hasName() && !isa<ParamDecl>(D) && !isa<AccessorDecl>(D))
     return std::string(); // Ignore.
-  if (D->getModuleContext()->isBuiltinModule() &&
-      !isa<BuiltinTupleDecl>(D))
+  if (D->getModuleContext()->isBuiltinModule() && !isa<BuiltinTupleDecl>(D))
     return std::string(); // Ignore.
   if (isa<ModuleDecl>(D))
     return std::string(); // Ignore.
 
-  auto interpretAsClangNode = [&options](const ValueDecl *D) -> ClangNode {
+  /// Checks whether \p D is a synthesized Clang declaration that should have a
+  /// Swift USR.
+  auto isSynthesizedDeclWithSwiftUSR = [](const ValueDecl *D) -> bool {
     auto *importer = D->getASTContext().getClangModuleLoader();
     ClangNode ClangN = importer->getEffectiveClangNode(D);
     if (auto ClangD = ClangN.getAsDecl()) {
@@ -210,67 +284,30 @@ swift::USRGenerationRequest::evaluate(Evaluator &evaluator, const ValueDecl *D,
       // But we want unique USRs for the above symbols, so use the clang USR
       // for the enum cases, and the Swift USR for the vars.
       //
-      if (!options.distinguishSynthesizedDecls) {
-        return ClangN;
-      }
       if (auto *ClangEnumConst = dyn_cast<clang::EnumConstantDecl>(ClangD)) {
         if (auto *ClangEnum =
                 dyn_cast<clang::EnumDecl>(ClangEnumConst->getDeclContext())) {
           if (ClangEnum->hasAttr<clang::NSErrorDomainAttr>() && isa<VarDecl>(D))
-            return ClangNode();
+            return true;
         }
       }
       if (D->getAttrs().hasAttribute<ClangImporterSynthesizedTypeAttr>()) {
-        return ClangNode();
+        return true;
       }
     }
-    return ClangN;
+    return false;
   };
 
-  llvm::SmallString<128> Buffer;
-  llvm::raw_svector_ostream OS(Buffer);
-
-  if (ClangNode ClangN = interpretAsClangNode(D)) {
-    if (auto ClangD = ClangN.getAsDecl()) {
-      bool Ignore = clang::index::generateUSRForDecl(ClangD, Buffer);
-      if (!Ignore) {
-        return std::string(Buffer.str());
-      } else {
-        return std::string();
-      }
+  if (!options.useSwiftUSR && (!options.distinguishSynthesizedDecls ||
+                               !isSynthesizedDeclWithSwiftUSR(D))) {
+    if (auto clangUSR = evaluateOrDefault(
+            evaluator, ClangUSRGenerationRequest{D}, std::nullopt)) {
+      return clangUSR.value();
     }
-
-    auto &Importer = *D->getASTContext().getClangModuleLoader();
-
-    auto ClangMacroInfo = ClangN.getAsMacro();
-    bool Ignore = clang::index::generateUSRForMacro(
-        D->getBaseIdentifier().str(),
-        ClangMacroInfo->getDefinitionLoc(),
-        Importer.getClangASTContext().getSourceManager(), Buffer);
-    if (!Ignore)
-      return std::string(Buffer.str());
-    else
-      return std::string();
   }
 
-  if (shouldUseObjCUSR(D)) {
-    if (printObjCUSR(D, OS)) {
-      return std::string();
-    } else {
-      return std::string(OS.str());
-    }
-  }
-
-  auto declIFaceTy = D->getInterfaceType();
-
-  // Invalid code.
-  if (declIFaceTy.findIf([](Type t) -> bool {
-        return t->is<ModuleType>();
-      }))
-    return std::string();
-
-  Mangle::ASTMangler NewMangler(D->getASTContext());
-  return NewMangler.mangleDeclAsUSR(D, getUSRSpacePrefix());
+  return evaluateOrDefault(evaluator, SwiftUSRGenerationRequest{D},
+                           std::string());
 }
 
 std::string ide::demangleUSR(StringRef mangled) {
@@ -307,10 +344,12 @@ bool ide::printModuleUSR(ModuleEntity Mod, raw_ostream &OS) {
 }
 
 bool ide::printValueDeclUSR(const ValueDecl *D, raw_ostream &OS,
-                            bool distinguishSynthesizedDecls) {
+                            bool distinguishSynthesizedDecls,
+                            bool useSwiftUSR) {
   auto result = evaluateOrDefault(
       D->getASTContext().evaluator,
-      USRGenerationRequest{D, {distinguishSynthesizedDecls}}, std::string());
+      USRGenerationRequest{D, {distinguishSynthesizedDecls, useSwiftUSR}},
+      std::string());
   if (result.empty())
     return true;
   OS << result;
diff --git a/lib/AST/UnqualifiedLookup.cpp b/lib/AST/UnqualifiedLookup.cpp
index 51820b41a9ca8..45f6ed4b3fcb1 100644
--- a/lib/AST/UnqualifiedLookup.cpp
+++ b/lib/AST/UnqualifiedLookup.cpp
@@ -483,6 +483,9 @@ void UnqualifiedLookupFactory::addImportedResults(const DeclContext *const dc) {
     nlOptions |= NL_ExcludeMacroExpansions;
   if (options.contains(Flags::ABIProviding))
     nlOptions |= NL_ABIProviding;
+  if (options.contains(Flags::IgnoreAccessControl))
+    nlOptions |= NL_IgnoreAccessControl;
+
   lookupInModule(dc, Name.getFullName(), CurModuleResults,
                  NLKind::UnqualifiedLookup, resolutionKind, dc,
                  Loc, nlOptions);
diff --git a/lib/ASTGen/CMakeLists.txt b/lib/ASTGen/CMakeLists.txt
index 46d88fef49174..6427618084d1d 100644
--- a/lib/ASTGen/CMakeLists.txt
+++ b/lib/ASTGen/CMakeLists.txt
@@ -14,6 +14,8 @@ if(SWIFT_BUILD_REGEX_PARSER_IN_COMPILER)
   add_pure_swift_host_library(_CompilerRegexParser STATIC
     "${COMPILER_REGEX_PARSER_SOURCES}"
   )
+  target_compile_options(_CompilerRegexParser PRIVATE
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>")
 else()
   # Dummy target for dependencies
   add_custom_target(_CompilerRegexParser)
diff --git a/lib/ASTGen/Sources/ASTGen/ASTGen.swift b/lib/ASTGen/Sources/ASTGen/ASTGen.swift
index f0a04bb1888da..86051f9f44dc2 100644
--- a/lib/ASTGen/Sources/ASTGen/ASTGen.swift
+++ b/lib/ASTGen/Sources/ASTGen/ASTGen.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -177,12 +177,12 @@ struct ASTGenVisitor {
 }
 
 extension ASTGenVisitor {
-  /// Obtains a bridged, `ASTContext`-owned "identifier".
+  /// Obtains a `ASTContext`-owned "identifier".
   ///
-  /// If the token text is `_`, return an empty identifier. If the token is an
+  /// If the token text is `_`, returns an empty identifier. If the token is an
   /// escaped identifier, backticks are stripped.
   @inline(__always)
-  func generateIdentifier(_ token: TokenSyntax) -> BridgedIdentifier {
+  func generateIdentifier(_ token: TokenSyntax) -> Identifier {
     if token.rawTokenKind == .wildcard {
       return nil
     }
@@ -193,32 +193,33 @@ extension ASTGenVisitor {
     return self.ctx.getIdentifier(text.bridged)
   }
 
-  /// Obtains a bridged, `ASTContext`-owned "identifier".
+  /// Obtains a `ASTContext`-owned "identifier".
   ///
-  /// If the `token` text is `nil`, return an empty identifier.
+  /// If the `token` text is `nil`, returns an empty identifier.
   @inline(__always)
-  func generateIdentifier(_ token: TokenSyntax?) -> BridgedIdentifier {
+  func generateIdentifier(_ token: TokenSyntax?) -> Identifier {
     token.map(generateIdentifier(_:)) ?? nil
   }
 
-  /// Obtains the start location of the node excluding leading trivia in the
+  /// Obtains the C++ start location of the node excluding leading trivia in the
   /// source buffer.
   @inline(__always)
-  func generateSourceLoc(_ node: some SyntaxProtocol) -> BridgedSourceLoc {
-    BridgedSourceLoc(at: node.positionAfterSkippingLeadingTrivia, in: self.base)
+  func generateSourceLoc(_ node: some SyntaxProtocol) -> SourceLoc {
+    SourceLoc(at: node.positionAfterSkippingLeadingTrivia, in: self.base)
   }
 
-  /// Obtains the start location of the node excluding leading trivia in the
+  /// Obtains the C++ start location of the node excluding leading trivia in the
   /// source buffer. If the `node` is nil returns an invalid source location.
   @inline(__always)
-  func generateSourceLoc(_ node: (some SyntaxProtocol)?) -> BridgedSourceLoc {
+  func generateSourceLoc(_ node: (some SyntaxProtocol)?) -> SourceLoc {
     node.map(generateSourceLoc(_:)) ?? nil
   }
 
-  /// Obtains a pair of bridged identifier and the bridged source location.
+  /// Obtains a pair of an `ASTContext`-owned identifier and a C++ source
+  /// location from `token`.
   @inline(__always)
   func generateIdentifierAndSourceLoc(_ token: TokenSyntax) -> (
-    identifier: BridgedIdentifier, sourceLoc: BridgedSourceLoc
+    identifier: Identifier, sourceLoc: SourceLoc
   ) {
     return (
       self.generateIdentifier(token),
@@ -226,12 +227,13 @@ extension ASTGenVisitor {
     )
   }
 
-  /// Obtains a pair of bridged identifier and the bridged source location.
+  /// Obtains a pair of an `ASTContext`-owned identifier and a C++ source
+  /// location from `token`.
   /// If `token` is `nil`, returns a pair of an empty identifier and an invalid
   /// source location.
   @inline(__always)
   func generateIdentifierAndSourceLoc(_ token: TokenSyntax?) -> (
-    identifier: BridgedIdentifier, sourceLoc: BridgedSourceLoc
+    identifier: Identifier, sourceLoc: SourceLoc
   ) {
     token.map(generateIdentifierAndSourceLoc(_:)) ?? (nil, nil)
   }
@@ -245,55 +247,55 @@ extension ASTGenVisitor {
     )
   }
 
-  /// Obtains bridged token source range from a pair of token nodes.
+  /// Obtains a C++ source range from a pair of token nodes.
   @inline(__always)
-  func generateSourceRange(start: TokenSyntax, end: TokenSyntax) -> BridgedSourceRange {
-    BridgedSourceRange(
+  func generateSourceRange(start: TokenSyntax, end: TokenSyntax) -> SourceRange {
+    .init(
       start: self.generateSourceLoc(start),
       end: self.generateSourceLoc(end)
     )
   }
 
-  /// Obtains bridged token source range of a syntax node.
+  /// Obtains the C++ source range of a syntax node.
   @inline(__always)
-  func generateSourceRange(_ node: some SyntaxProtocol) -> BridgedSourceRange {
+  func generateSourceRange(_ node: some SyntaxProtocol) -> SourceRange {
     guard let start = node.firstToken(viewMode: .sourceAccurate) else {
-      return BridgedSourceRange(start: nil, end: nil)
+      return .init()
     }
     return generateSourceRange(start: start, end: node.lastToken(viewMode: .sourceAccurate)!)
   }
 
-  /// Obtains bridged token source range of a syntax node.
+  /// Obtains the C++ source range of a syntax node.
   @inline(__always)
-  func generateSourceRange(_ node: (some SyntaxProtocol)?) -> BridgedSourceRange {
+  func generateSourceRange(_ node: (some SyntaxProtocol)?) -> SourceRange {
     guard let node = node else {
-      return BridgedSourceRange(start: nil, end: nil)
+      return .init()
     }
     return generateSourceRange(node)
   }
 
-  /// Obtains bridged token source range for a syntax node.
-  /// Unlike `generateSourceRange(_:)`, this correctly emulates the string/regex literal token SourceLoc in AST.
-  func generateImplicitBraceRange(_ node: some SyntaxProtocol) -> BridgedSourceRange {
+  /// Obtains the C++ source range of a syntax node.
+  /// Unlike `generateSourceRange(_:)`, this correctly emulates the string/regex literal token `SourceLoc` in AST.
+  func generateImplicitBraceRange(_ node: some SyntaxProtocol) -> SourceRange {
     let loc = self.generateSourceLoc(node)
     if let endTok = node.lastToken(viewMode: .sourceAccurate) {
       switch endTok.parent?.kind {
       case .stringLiteralExpr, .regexLiteralExpr:
         // string/regex literal are single token in AST.
-        return BridgedSourceRange(start:loc, end: self.generateSourceLoc(endTok.parent))
+        return .init(start: loc, end: self.generateSourceLoc(endTok.parent))
       default:
-        return BridgedSourceRange(start:loc, end: self.generateSourceLoc(endTok))
+        return .init(start: loc, end: self.generateSourceLoc(endTok))
       }
     } else {
-      return BridgedSourceRange(start:loc, end: loc)
+      return .init(start:loc, end: loc)
     }
   }
 
-  /// Obtains bridged character source range.
+  /// Obtains a C++ character source range.
   @inline(__always)
-  func generateCharSourceRange(start: AbsolutePosition, length: SourceLength) -> BridgedCharSourceRange {
-    BridgedCharSourceRange(
-      start: BridgedSourceLoc(at: start, in: self.base),
+  func generateCharSourceRange(start: AbsolutePosition, length: SourceLength) -> CharSourceRange {
+    .init(
+      start: SourceLoc(at: start, in: self.base),
       byteLength: UInt32(length.utf8Length)
     )
   }
diff --git a/lib/ASTGen/Sources/ASTGen/Availability.swift b/lib/ASTGen/Sources/ASTGen/Availability.swift
index fd0b1be95e1fb..f51365193f7ab 100644
--- a/lib/ASTGen/Sources/ASTGen/Availability.swift
+++ b/lib/ASTGen/Sources/ASTGen/Availability.swift
@@ -21,8 +21,8 @@ import SwiftIfConfig
 extension ASTGenVisitor {
   /// Implementation detail for `generateAvailableAttr(attribute:)` and `generateSpecializeAttr(attribute:)`.
   func generateAvailableAttr(
-    atLoc: BridgedSourceLoc,
-    range: BridgedSourceRange,
+    atLoc: SourceLoc,
+    range: SourceRange,
     attrName: SyntaxText,
     args: AvailabilityArgumentListSyntax
   ) -> [BridgedAvailableAttr] {
@@ -66,8 +66,8 @@ extension ASTGenVisitor {
   }
 
   func generateAvailableAttrShorthand(
-    atLoc: BridgedSourceLoc,
-    range: BridgedSourceRange,
+    atLoc: SourceLoc,
+    range: SourceRange,
     args: AvailabilityArgumentListSyntax,
     isSPI: Bool
   ) -> [BridgedAvailableAttr] {
@@ -101,9 +101,9 @@ extension ASTGenVisitor {
         introduced: spec.rawVersion,
         introducedRange: spec.versionRange,
         deprecated: BridgedVersionTuple(),
-        deprecatedRange: BridgedSourceRange(),
+        deprecatedRange: SourceRange(),
         obsoleted: BridgedVersionTuple(),
-        obsoletedRange: BridgedSourceRange(),
+        obsoletedRange: SourceRange(),
         isSPI: isSPI
       )
       attr.setIsGroupMember()
@@ -121,8 +121,8 @@ extension ASTGenVisitor {
   }
 
   func generateAvailableAttrExtended(
-    atLoc: BridgedSourceLoc,
-    range: BridgedSourceRange,
+    atLoc: SourceLoc,
+    range: SourceRange,
     args: AvailabilityArgumentListSyntax,
     isSPI: Bool
   ) -> BridgedAvailableAttr? {
@@ -155,7 +155,7 @@ extension ASTGenVisitor {
 
     struct VersionAndRange {
       let version: VersionTuple
-      let range: BridgedSourceRange
+      let range: SourceRange
     }
 
     var introduced: VersionAndRange? = nil
@@ -263,11 +263,11 @@ extension ASTGenVisitor {
       message: message ?? BridgedStringRef(),
       renamed: renamed ?? BridgedStringRef(),
       introduced: introduced?.version.bridged ?? BridgedVersionTuple(),
-      introducedRange: introduced?.range ?? BridgedSourceRange(),
+      introducedRange: introduced?.range ?? SourceRange(),
       deprecated: deprecated?.version.bridged ?? BridgedVersionTuple(),
-      deprecatedRange: deprecated?.range ?? BridgedSourceRange(),
+      deprecatedRange: deprecated?.range ?? SourceRange(),
       obsoleted: obsoleted?.version.bridged ?? BridgedVersionTuple(),
-      obsoletedRange: obsoleted?.range ?? BridgedSourceRange(),
+      obsoletedRange: obsoleted?.range ?? SourceRange(),
       isSPI: isSPI
     )
   }
@@ -369,7 +369,7 @@ extension ASTGenVisitor {
     return result
   }
 
-  typealias GeneratedPlatformVersion = (platform: BridgedPlatformKind, version: BridgedVersionTuple)
+  typealias GeneratedPlatformVersion = (platform: swift.PlatformKind, version: BridgedVersionTuple)
 
   func generate(platformVersionList node: PlatformVersionItemListSyntax) -> [GeneratedPlatformVersion] {
     var result: [GeneratedPlatformVersion] = []
@@ -380,9 +380,9 @@ extension ASTGenVisitor {
       let version = self.generate(versionTuple: platformVersionNode.version)?.bridged ?? BridgedVersionTuple()
 
       // If the name is a platform name, use it.
-      let platform = BridgedPlatformKind(from: platformName.bridged)
-      if platform != .none {
-        result.append((platform: platform, version: version))
+      let platform = BridgedOptionalPlatformKind(from: platformName.bridged)
+      guard !platform.hasValue else {
+        result.append((platform: platform.value, version: version))
         continue
       }
 
@@ -397,11 +397,12 @@ extension ASTGenVisitor {
             let spec = BridgedAvailabilitySpec(raw: UnsafeMutableRawPointer(mutating: ptr))
             let domainOrIdentifier = spec.domainOrIdentifier
             precondition(!domainOrIdentifier.isDomain)
-            let platform = BridgedPlatformKind(from: domainOrIdentifier.asIdentifier)
-            guard platform != .none else {
+            let platform = BridgedOptionalPlatformKind(from: domainOrIdentifier.asIdentifier)
+            guard platform.hasValue else {
+              // TODO: Diagnose?
               continue
             }
-            result.append((platform: platform, version: spec.rawVersion))
+            result.append((platform: platform.value, version: spec.rawVersion))
           }
         }
         continue
diff --git a/lib/ASTGen/Sources/ASTGen/Bridge.swift b/lib/ASTGen/Sources/ASTGen/Bridge.swift
index f15534677d9cd..257a4cca8642b 100644
--- a/lib/ASTGen/Sources/ASTGen/Bridge.swift
+++ b/lib/ASTGen/Sources/ASTGen/Bridge.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,6 +15,12 @@ import BasicBridging
 import SwiftIfConfig
 @_spi(RawSyntax) import SwiftSyntax
 
+public typealias Identifier = swift.Identifier
+public typealias DeclBaseName = swift.DeclBaseName
+public typealias SourceLoc = swift.SourceLoc
+public typealias SourceRange = swift.SourceRange
+public typealias CharSourceRange = swift.CharSourceRange
+
 public protocol BridgedNullable: ExpressibleByNilLiteral {
   associatedtype RawPtr
   init(raw: RawPtr?)
@@ -25,8 +31,8 @@ extension BridgedNullable {
   }
 }
 
-extension BridgedSourceLoc: /*@retroactive*/ swiftASTGen.BridgedNullable {}
-extension BridgedIdentifier: /*@retroactive*/ swiftASTGen.BridgedNullable {}
+extension SourceLoc: /*@retroactive*/ swiftASTGen.BridgedNullable {}
+extension Identifier: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 extension BridgedNullableDecl: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 extension BridgedNullableExpr: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 extension BridgedNullableStmt: /*@retroactive*/ swiftASTGen.BridgedNullable {}
@@ -41,7 +47,7 @@ extension BridgedNullableCustomAttributeInitializer: /*@retroactive*/ swiftASTGe
 extension BridgedNullableArgumentList: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 extension BridgedNullableVarDecl: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 
-extension BridgedIdentifier: /*@retroactive*/ Swift.Equatable {
+extension Identifier: /*@retroactive*/ Swift.Equatable {
   public static func == (lhs: Self, rhs: Self) -> Bool {
     lhs.raw == rhs.raw
   }
@@ -101,15 +107,17 @@ extension BridgedVarDecl: BridgedHasNullable {
   typealias Nullable = BridgedNullableVarDecl
 }
 
-public extension BridgedSourceLoc {
-  /// Form a source location at the given absolute position in `buffer`.
+public extension SourceLoc {
+  /// Form a C++ source location at the given absolute position in `buffer`.
   init(
     at position: AbsolutePosition,
     in buffer: UnsafeBufferPointer<UInt8>
   ) {
     precondition(position.utf8Offset >= 0 && position.utf8Offset <= buffer.count)
-    self = BridgedSourceLoc(raw: buffer.baseAddress!).advanced(by: position.utf8Offset)
+    self = SourceLoc(raw: buffer.baseAddress!.advanced(by: position.utf8Offset))
   }
+
+  var isValid: Bool { isValid() }
 }
 
 extension BridgedLabeledStmtInfo: /*@retroactive*/ Swift.ExpressibleByNilLiteral {
@@ -118,21 +126,6 @@ extension BridgedLabeledStmtInfo: /*@retroactive*/ Swift.ExpressibleByNilLiteral
   }
 }
 
-extension String {
-  init(bridged: BridgedStringRef) {
-    self.init(
-      decoding: UnsafeBufferPointer(start: bridged.data, count: bridged.count),
-      as: UTF8.self
-    )
-  }
-
-  public mutating func withBridgedString<R>(_ body: (BridgedStringRef) throws -> R) rethrows -> R {
-    try withUTF8 { buffer in
-      try body(BridgedStringRef(data: buffer.baseAddress, count: buffer.count))
-    }
-  }
-}
-
 extension SyntaxText {
   var bridged: BridgedStringRef {
     BridgedStringRef(data: self.baseAddress, count: self.count)
@@ -190,48 +183,48 @@ extension VersionTuple {
 }
 
 extension SyntaxProtocol {
-  /// Obtains the bridged start location of the node excluding leading trivia in the source buffer provided by `astgen`
+  /// Obtains the C++ start location of the node excluding leading trivia in the source buffer provided by `astgen`
   ///
   /// - Parameter astgen: The visitor providing the source buffer.
   @available(*, deprecated, message: "use ASTContext.bridgedSourceLoc(syntax:)")
   @inline(__always)
-  func bridgedSourceLoc(in astgen: ASTGenVisitor) -> BridgedSourceLoc {
+  func bridgedSourceLoc(in astgen: ASTGenVisitor) -> SourceLoc {
     astgen.generateSourceLoc(self)
   }
 }
 
 extension Optional where Wrapped: SyntaxProtocol {
-  /// Obtains the bridged start location of the node excluding leading trivia in the source buffer provided by `astgen`.
+  /// Obtains the C++ start location of the node excluding leading trivia in the source buffer provided by `astgen`.
   ///
   /// - Parameter astgen: The visitor providing the source buffer.
   @available(*, deprecated, message: "use ASTContext.bridgedSourceLoc(syntax:)")
   @inline(__always)
-  func bridgedSourceLoc(in astgen: ASTGenVisitor) -> BridgedSourceLoc {
+  func bridgedSourceLoc(in astgen: ASTGenVisitor) -> SourceLoc {
     astgen.generateSourceLoc(self)
   }
 }
 
 extension TokenSyntax {
-  /// Obtains a bridged, `ASTContext`-owned copy of this token's text.
+  /// Obtains an `ASTContext`-owned copy of this token's text.
   ///
   /// - Parameter astgen: The visitor providing the `ASTContext`.
   @available(*, deprecated, message: "use ASTContext.bridgedIdentifier(token:)")
   @inline(__always)
-  func bridgedIdentifier(in astgen: ASTGenVisitor) -> BridgedIdentifier {
+  func bridgedIdentifier(in astgen: ASTGenVisitor) -> Identifier {
     astgen.generateIdentifier(self)
   }
 
-  /// Obtains a bridged, `ASTContext`-owned copy of this token's text, and its bridged start location in the
+  /// Obtains a `ASTContext`-owned copy of this token's text, and its C++ start location in the
   /// source buffer provided by `astgen`.
   ///
   /// - Parameter astgen: The visitor providing the `ASTContext` and source buffer.
   @available(*, deprecated, message: "use ASTContext.bridgedIdentifierAndSourceLoc(token:)")
   @inline(__always)
-  func bridgedIdentifierAndSourceLoc(in astgen: ASTGenVisitor) -> (BridgedIdentifier, BridgedSourceLoc) {
+  func bridgedIdentifierAndSourceLoc(in astgen: ASTGenVisitor) -> (Identifier, SourceLoc) {
     astgen.generateIdentifierAndSourceLoc(self)
   }
 
-  /// Obtains a bridged, `ASTContext`-owned copy of this token's text, and its bridged start location in the
+  /// Obtains a `ASTContext`-owned copy of this token's text, and its C++ start location in the
   /// source buffer provided by `astgen`.
   ///
   /// - Parameter astgen: The visitor providing the `ASTContext` and source buffer.
@@ -243,27 +236,27 @@ extension TokenSyntax {
 }
 
 extension Optional<TokenSyntax> {
-  /// Obtains a bridged, `ASTContext`-owned copy of this token's text.
+  /// Obtains a `ASTContext`-owned copy of this token's text.
   ///
   /// - Parameter astgen: The visitor providing the `ASTContext`.
   @available(*, deprecated, message: "use ASTContext.bridgedIdentifier(token:)")
   @inline(__always)
-  func bridgedIdentifier(in astgen: ASTGenVisitor) -> BridgedIdentifier {
+  func bridgedIdentifier(in astgen: ASTGenVisitor) -> Identifier {
     astgen.generateIdentifier(self)
   }
 
-  /// Obtains a bridged, `ASTContext`-owned copy of this token's text, and its bridged start location in the
+  /// Obtains a `ASTContext`-owned copy of this token's text, and its C++ start location in the
   /// source buffer provided by `astgen` excluding leading trivia.
   ///
   /// - Parameter astgen: The visitor providing the `ASTContext` and source buffer.
   @available(*, deprecated, message: "use ASTContext.bridgedIdentifierAndSourceLoc(token:)")
   @inline(__always)
-  func bridgedIdentifierAndSourceLoc(in astgen: ASTGenVisitor) -> (BridgedIdentifier, BridgedSourceLoc) {
+  func bridgedIdentifierAndSourceLoc(in astgen: ASTGenVisitor) -> (Identifier, SourceLoc) {
     astgen.generateIdentifierAndSourceLoc(self)
   }
 }
 
-extension BridgedSourceRange {
+extension SourceRange {
   @available(*, deprecated, message: "use ASTContext.bridgedSourceRange(startToken:endToken:)")
   @inline(__always)
   init(startToken: TokenSyntax, endToken: TokenSyntax, in astgen: ASTGenVisitor) {
diff --git a/lib/ASTGen/Sources/ASTGen/BuiltinPound.swift b/lib/ASTGen/Sources/ASTGen/BuiltinPound.swift
index 8dbe88d23359b..93b6c367d7fd9 100644
--- a/lib/ASTGen/Sources/ASTGen/BuiltinPound.swift
+++ b/lib/ASTGen/Sources/ASTGen/BuiltinPound.swift
@@ -76,7 +76,7 @@ extension ASTGenVisitor {
       let keypathExpr = self.generateObjCKeyPathExpr(freestandingMacroExpansion: node)
       return .generated(.expr(keypathExpr))
 
-    case .assert where ctx.langOptsHasFeature(.StaticAssert):
+    case .assert where ctx.langOpts.hasFeature(.StaticAssert):
       let assertStmtOpt = self.generatePoundAssertStmt(freestandingMacroExpansion: node)
       return .generated(assertStmtOpt.map({ .stmt($0.asStmt) }))
 
@@ -143,7 +143,7 @@ extension ASTGenVisitor {
   }
 
   func generatePoundAssertStmt(freestandingMacroExpansion node: some FreestandingMacroExpansionSyntax) -> BridgedPoundAssertStmt? {
-    assert(self.ctx.langOptsHasFeature(.StaticAssert))
+    assert(self.ctx.langOpts.hasFeature(.StaticAssert))
     var args = node.arguments[...]
     let conditionExpr = self.generateConsumingAttrOption(args: &args, label: nil) { conditionNode in
       self.generate(expr: conditionNode)
diff --git a/lib/ASTGen/Sources/ASTGen/CMakeLists.txt b/lib/ASTGen/Sources/ASTGen/CMakeLists.txt
index 91271f87e84cb..678a23509cc43 100644
--- a/lib/ASTGen/Sources/ASTGen/CMakeLists.txt
+++ b/lib/ASTGen/Sources/ASTGen/CMakeLists.txt
@@ -9,6 +9,7 @@ add_pure_swift_host_library(swiftASTGen STATIC CXX_INTEROP
   Decls.swift
   Diagnostics.swift
   DiagnosticsBridge.swift
+  EmbeddedSupport.swift
   Exprs.swift
   Fingerprint.swift
   Generics.swift
@@ -26,6 +27,7 @@ add_pure_swift_host_library(swiftASTGen STATIC CXX_INTEROP
   DEPENDENCIES
     swiftAST
   SWIFT_DEPENDENCIES
+    _CompilerSwiftCompilerPluginMessageHandling
     _CompilerRegexParser
     _CompilerSwiftSyntax
     _CompilerSwiftIfConfig
@@ -35,4 +37,5 @@ add_pure_swift_host_library(swiftASTGen STATIC CXX_INTEROP
     _CompilerSwiftParser
     _CompilerSwiftParserDiagnostics
     _CompilerSwiftDiagnostics
+    swiftBasicSwift
 )
diff --git a/lib/ASTGen/Sources/ASTGen/CompilerBuildConfiguration.swift b/lib/ASTGen/Sources/ASTGen/CompilerBuildConfiguration.swift
index 6eae1e83c0a9a..3dbc62d4d760a 100644
--- a/lib/ASTGen/Sources/ASTGen/CompilerBuildConfiguration.swift
+++ b/lib/ASTGen/Sources/ASTGen/CompilerBuildConfiguration.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -10,42 +10,46 @@
 //
 //===----------------------------------------------------------------------===//
 
+import BasicBridging
 import ASTBridging
+import swiftBasicSwift
 import SwiftDiagnostics
 @_spi(Compiler) import SwiftIfConfig
 @_spi(ExperimentalLanguageFeatures) import SwiftParser
 @_spi(ExperimentalLanguageFeatures) import SwiftSyntax
 
+extension BridgedASTContext {
+  /// Retrieve the (cached) static build configuration for this ASTContext.
+  public var staticBuildConfiguration: StaticBuildConfiguration {
+    staticBuildConfigurationPtr.assumingMemoryBound(
+      to: StaticBuildConfiguration.self
+    ).pointee
+  }
+}
+
 /// A build configuration that uses the compiler's ASTContext to answer
 /// queries.
 struct CompilerBuildConfiguration: BuildConfiguration {
   let ctx: BridgedASTContext
+  let staticBuildConfiguration: StaticBuildConfiguration
   let sourceBuffer: UnsafeBufferPointer<UInt8>
 
   init(ctx: BridgedASTContext, sourceBuffer: UnsafeBufferPointer<UInt8>) {
     self.ctx = ctx
+    self.staticBuildConfiguration = ctx.staticBuildConfiguration
     self.sourceBuffer = sourceBuffer
   }
 
-  func isCustomConditionSet(name: String) throws -> Bool {
-    var name = name
-    return name.withBridgedString { nameRef in
-      ctx.langOptsCustomConditionSet(nameRef)
-    }
+  func isCustomConditionSet(name: String) -> Bool {
+    staticBuildConfiguration.isCustomConditionSet(name: name)
   }
   
-  func hasFeature(name: String) throws -> Bool {
-    var name = name
-    return name.withBridgedString { nameRef in
-      ctx.langOptsHasFeatureNamed(nameRef)
-    }
+  func hasFeature(name: String) -> Bool {
+    staticBuildConfiguration.hasFeature(name: name)
   }
   
-  func hasAttribute(name: String) throws -> Bool {
-    var name = name
-    return name.withBridgedString { nameRef in
-      ctx.langOptsHasAttributeNamed(nameRef)
-    }
+  func hasAttribute(name: String) -> Bool {
+    staticBuildConfiguration.hasAttribute(name: name)
   }
   
   func canImport(
@@ -74,7 +78,7 @@ struct CompilerBuildConfiguration: BuildConfiguration {
       versionComponents.withUnsafeBufferPointer { versionComponentsBuf in
         ctx.canImport(
           importPath: bridgedImportPathStr,
-          location: BridgedSourceLoc(
+          location: SourceLoc(
             at: importPath.first!.0.position,
             in: sourceBuffer
           ),
@@ -86,85 +90,50 @@ struct CompilerBuildConfiguration: BuildConfiguration {
     }
   }
   
-  func isActiveTargetOS(name: String) throws -> Bool {
-    var name = name
-    return name.withBridgedString { nameRef in
-      ctx.langOptsIsActiveTargetOS(nameRef)
-    }
+  func isActiveTargetOS(name: String) -> Bool {
+    staticBuildConfiguration.isActiveTargetOS(name: name)
   }
   
-  func isActiveTargetArchitecture(name: String) throws -> Bool {
-    var name = name
-    return name.withBridgedString { nameRef in
-      ctx.langOptsIsActiveTargetArchitecture(nameRef)
-    }
+  func isActiveTargetArchitecture(name: String) -> Bool {
+    staticBuildConfiguration.isActiveTargetArchitecture(name: name)
   }
   
-  func isActiveTargetEnvironment(name: String) throws -> Bool {
-    var name = name
-    return name.withBridgedString { nameRef in
-      ctx.langOptsIsActiveTargetEnvironment(nameRef)
-    }
+  func isActiveTargetEnvironment(name: String) -> Bool {
+    staticBuildConfiguration.isActiveTargetEnvironment(name: name)
   }
   
   func isActiveTargetRuntime(name: String) throws -> Bool {
-    var name = name
-
     // Complain if the provided runtime isn't one of the known values.
     switch name {
     case "_Native", "_ObjC", "_multithreaded": break
     default: throw IfConfigError.unexpectedRuntimeCondition
     }
 
-    return name.withBridgedString { nameRef in
-      ctx.langOptsIsActiveTargetRuntime(nameRef)
-    }
+    return staticBuildConfiguration.isActiveTargetRuntime(name: name)
   }
-  
-  func isActiveTargetPointerAuthentication(name: String) throws -> Bool {
-    var name = name
-    return name.withBridgedString { nameRef in
-      ctx.langOptsIsActiveTargetPtrAuth(nameRef)
-    }
+
+  func isActiveTargetPointerAuthentication(name: String) -> Bool {
+    staticBuildConfiguration.isActiveTargetPointerAuthentication(name: name)
   }
   
   var targetPointerBitWidth: Int {
-    Int(ctx.langOptsTargetPointerBitWidth)
+    staticBuildConfiguration.targetPointerBitWidth
   }
 
   var targetAtomicBitWidths: [Int] {
-    var bitWidthsBuf: UnsafeMutablePointer<SwiftInt>? = nil
-    let count = ctx.langOptsGetTargetAtomicBitWidths(&bitWidthsBuf)
-    let bitWidths = Array(UnsafeMutableBufferPointer(start: bitWidthsBuf, count: count))
-    deallocateIntBuffer(bitWidthsBuf);
-    return bitWidths
+    staticBuildConfiguration.targetAtomicBitWidths
   }
 
   var endianness: Endianness {
-    switch ctx.langOptsTargetEndianness {
-    case .EndianBig: return .big
-    case .EndianLittle: return .little
-    }
+    staticBuildConfiguration.endianness
   }
 
-  var languageVersion: VersionTuple { 
-    var componentsBuf: UnsafeMutablePointer<SwiftInt>? = nil
-    let count = ctx.langOptsGetLanguageVersion(&componentsBuf)
-    let version = VersionTuple(
-      components: Array(UnsafeMutableBufferPointer(start: componentsBuf, count: count))
-    )
-    deallocateIntBuffer(componentsBuf);
-    return version
+  var languageVersion: VersionTuple {
+    staticBuildConfiguration.languageVersion
   }
 
-  var compilerVersion: VersionTuple { 
-    var componentsBuf: UnsafeMutablePointer<SwiftInt>? = nil
-    let count = ctx.langOptsGetCompilerVersion(&componentsBuf)
-    let version = VersionTuple(
-      components: Array(UnsafeMutableBufferPointer(start: componentsBuf, count: count))
-    )
-    deallocateIntBuffer(componentsBuf);
-    return version
+  var compilerVersion: VersionTuple {
+    staticBuildConfiguration.compilerVersion
   }
 }
 
diff --git a/lib/ASTGen/Sources/ASTGen/DeclAttrs.swift b/lib/ASTGen/Sources/ASTGen/DeclAttrs.swift
index 7d80b663340f0..e77859ba11836 100644
--- a/lib/ASTGen/Sources/ASTGen/DeclAttrs.swift
+++ b/lib/ASTGen/Sources/ASTGen/DeclAttrs.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -21,17 +21,17 @@ extension ASTGenVisitor {
   struct DeclAttributesResult {
     var attributes: BridgedDeclAttributes
     var staticSpelling: BridgedStaticSpelling
-    var staticLoc: BridgedSourceLoc
+    var staticLoc: SourceLoc
   }
 
   func generateDeclAttributes(_ node: some WithAttributesSyntax & WithModifiersSyntax, allowStatic: Bool) -> DeclAttributesResult {
     var attrs = BridgedDeclAttributes()
     var staticSpelling: BridgedStaticSpelling = .none
-    var staticLoc: BridgedSourceLoc = nil
+    var staticLoc: SourceLoc = nil
 
     // Comments.
     COMMENT: if
-      self.ctx.langOptsAttachCommentsToDecls,
+      self.ctx.langOpts.attachCommentsToDecls,
       let firstTok = node.firstToken(viewMode: .sourceAccurate)
     {
       var pos = firstTok.position
@@ -115,237 +115,254 @@ extension ASTGenVisitor {
 
     if let identTy = node.attributeName.as(IdentifierTypeSyntax.self) {
       let attrName = identTy.name.rawText
-      let attrKind = BridgedDeclAttrKind(from: attrName.bridged)
+      let attrKind: swift.DeclAttrKind?
+      do {
+        let bridgedOptional = BridgedOptionalDeclAttrKind(from: attrName.bridged)
+        attrKind = if bridgedOptional.hasValue {
+          bridgedOptional.value
+        } else {
+          nil
+        }
+      }
+
       switch attrKind {
-      case .execution:
-        return handle(self.generateExecutionAttr(attribute: node)?.asDeclAttribute)
       case .ABI:
         return handle(self.generateABIAttr(attribute: node)?.asDeclAttribute)
-      case .alignment:
+      case .Alignment:
         return handle(self.generateAlignmentAttr(attribute: node)?.asDeclAttribute)
-      case .allowFeatureSuppression:
+      case .AllowFeatureSuppression:
         return handle(self.generateAllowFeatureSuppressionAttr(attribute: node, attrName: attrName)?.asDeclAttribute)
-      case .available:
+      case .Available:
         return self.generateAvailableAttr(attribute: node, attrName: attrName).forEach { handle($0.asDeclAttribute) }
-      case .backDeployed:
+      case .BackDeployed:
         return self.generateBackDeployedAttr(attribute: node).forEach { handle($0.asDeclAttribute) }
-      case .cDecl:
+      case .CDecl:
         return handle(self.generateCDeclAttr(attribute: node)?.asDeclAttribute)
-      case .derivative:
+      case .Derivative:
         return handle(self.generateDerivativeAttr(attribute: node)?.asDeclAttribute)
-      case .differentiable:
+      case .Differentiable:
         return handle(self.generateDifferentiableAttr(attribute: node)?.asDeclAttribute)
-      case .dynamicReplacement:
+      case .DynamicReplacement:
         return handle(self.generateDynamicReplacementAttr(attribute: node)?.asDeclAttribute)
-      case .documentation:
+      case .Documentation:
         return handle(self.generateDocumentationAttr(attribute: node)?.asDeclAttribute)
-      case .effects:
+      case .Effects:
         return handle(self.generateEffectsAttr(attribute: node)?.asDeclAttribute)
-      case .exclusivity:
+      case .Exclusivity:
         return handle(self.generateExclusivityAttr(attribute: node)?.asDeclAttribute)
-      case .expose:
+      case .Expose:
         return handle(self.generateExposeAttr(attribute: node)?.asDeclAttribute)
-      case .extern:
+      case .Extern:
         return handle(self.generateExternAttr(attribute: node)?.asDeclAttribute)
-      case .implements:
+      case .Implements:
         return handle(self.generateImplementsAttr(attribute: node)?.asDeclAttribute)
-      case .inline:
+      case .Inline:
         return handle(self.generateInlineAttr(attribute: node)?.asDeclAttribute)
-      case .lifetime:
+      case .Lifetime:
         return handle(self.generateLifetimeAttr(attribute: node)?.asDeclAttribute)
-      case .macroRole:
+      case .MacroRole:
         return handle(self.generateMacroRoleAttr(attribute: node, attrName: attrName)?.asDeclAttribute)
-      case .nonSendable:
+      case .NonSendable:
         return handle(self.generateNonSendableAttr(attribute: node)?.asDeclAttribute)
-      case .objC:
+      case .ObjC:
         return handle(self.generateObjCAttr(attribute: node)?.asDeclAttribute)
-      case .objCImplementation:
+      case .ObjCImplementation:
         return handle(self.generateObjCImplementationAttr(attribute: node)?.asDeclAttribute)
-      case .objCRuntimeName:
+      case .ObjCRuntimeName:
         return handle(self.generateObjCRuntimeNameAttr(attribute: node)?.asDeclAttribute)
-      case .optimize:
+      case .Optimize:
         return handle(self.generateOptimizeAttr(attribute: node)?.asDeclAttribute)
-      case .originallyDefinedIn:
+      case .OriginallyDefinedIn:
         return self.generateOriginallyDefinedInAttr(attribute: node).forEach { handle($0.asDeclAttribute) }
-      case .privateImport:
+      case .PrivateImport:
         return handle(self.generatePrivateImportAttr(attribute: node)?.asDeclAttribute)
-      case .projectedValueProperty:
+      case .ProjectedValueProperty:
         return handle(self.generateProjectedValuePropertyAttr(attribute: node)?.asDeclAttribute)
-      case .rawLayout:
+      case .RawLayout:
         return handle(self.generateRawLayoutAttr(attribute: node)?.asDeclAttribute)
-      case .section:
+      case .Section:
         return handle(self.generateSectionAttr(attribute: node)?.asDeclAttribute)
-      case .semantics:
+      case .Semantics:
         return handle(self.generateSemanticsAttr(attribute: node)?.asDeclAttribute)
-      case .silGenName:
+      case .SILGenName:
         return handle(self.generateSILGenNameAttr(attribute: node)?.asDeclAttribute)
-      case .specialize:
+      case .Specialize:
         return handle(self.generateSpecializeAttr(attribute: node, attrName: attrName)?.asDeclAttribute)
-      case .spiAccessControl:
+      case .Specialized:
+        return handle(self.generateSpecializedAttr(attribute: node, attrName: attrName)?.asDeclAttribute)
+      case .SPIAccessControl:
         return handle(self.generateSPIAccessControlAttr(attribute: node)?.asDeclAttribute)
-      case .storageRestrictions:
+      case .StorageRestrictions:
         return handle(self.generateStorageRestrictionAttr(attribute: node)?.asDeclAttribute)
-      case .swiftNativeObjCRuntimeBase:
+      case .SwiftNativeObjCRuntimeBase:
         return handle(self.generateSwiftNativeObjCRuntimeBaseAttr(attribute: node)?.asDeclAttribute)
-      case .transpose:
+      case .Transpose:
         return handle(self.generateTransposeAttr(attribute: node)?.asDeclAttribute)
-      case .typeEraser:
+      case .TypeEraser:
         return handle(self.generateTypeEraserAttr(attribute: node)?.asDeclAttribute)
-      case .unavailableFromAsync:
+      case .UnavailableFromAsync:
         return handle(self.generateUnavailableFromAsyncAttr(attribute: node)?.asDeclAttribute)
-      case .reasync:
-        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .atReasync))
-      case .rethrows:
-        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .atRethrows))
-      case .none where attrName == "_unavailableInEmbedded":
+      case .Reasync:
+        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .AtReasync))
+      case .Rethrows:
+        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .AtRethrows))
+      case .Concurrent:
+        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .Concurrent))
+      case nil where attrName == "_unavailableInEmbedded":
         return handle(self.generateUnavailableInEmbeddedAttr(attribute: node)?.asDeclAttribute)
 
       // Renamed attributes.
-      case .none where attrName == "_functionBuilder":
+      case nil where attrName == "_functionBuilder":
         // TODO: Diagnostics. '_functionBuilder' is renamed to 'resultBuilder'
-        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .resultBuilder))
-      case .none where attrName == "_inlineable":
+        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .ResultBuilder))
+      case nil where attrName == "_inlineable":
         // TODO: Diagnose.
-        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .inlinable))
-      case .none where attrName == "inlineable":
+        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .Inlinable))
+      case nil where attrName == "inlineable":
         // TODO: Diagnose.
-        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .inlinable))
-      case .none where attrName == "_versioned":
+        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .Inlinable))
+      case nil where attrName == "_versioned":
         // TODO: Diagnose.
-        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .usableFromInline))
+        return handle(self.generateSimpleDeclAttr(attribute: node, kind: .UsableFromInline))
 
       // Simple attributes.
-      case .addressableSelf,
-        .addressableForDependencies,
-        .alwaysEmitConformanceMetadata,
-        .alwaysEmitIntoClient,
-        .atReasync,
-        .atRethrows,
-        .borrowed,
-        .compilerInitialized,
-        .constVal,
-        .constInitialized,
-        .dynamicCallable,
-        .eagerMove,
-        .exported,
-        .discardableResult,
-        .disfavoredOverload,
-        .dynamicMemberLookup,
-        .emitAssemblyVisionRemarks,
-        .extractConstantsFromMembers,
-        .fixedLayout,
-        .frozen,
-        .gkInspectable,
-        .globalActor,
-        .hasInitialValue,
-        .hasMissingDesignatedInitializers,
-        .hasStorage,
-        .ibAction,
-        .ibDesignable,
-        .ibInspectable,
-        .ibOutlet,
-        .ibSegueAction,
-        .implementationOnly,
-        .implicitSelfCapture,
-        .inheritActorContext,
-        .inheritsConvenienceInitializers,
-        .inlinable,
-        .isolated,
-        .lexicalLifetimes,
-        .lldbDebuggerFunction,
-        .mainType,
-        .marker,
-        .moveOnly,
-        .noAllocation,
-        .noDerivative,
-        .noEagerMove,
-        .noExistentials,
-        .noRuntime,
-        .noImplicitCopy,
-        .noLocks,
-        .noMetadata,
-        .noObjCBridging,
-        .nonEphemeral,
-        .nonEscapable,
-        .nonObjC,
-        .nonOverride,
-        .nsApplicationMain,
-        .nsCopying,
-        .nsManaged,
-        .objCMembers,
-        .objCNonLazyRealization,
-        .preconcurrency,
-        .preInverseGenerics,
-        .propertyWrapper,
-        .requiresStoredPropertyInits,
-        .resultBuilder,
-        .safe,
-        .sendable,
-        .sensitive,
-        .spiOnly,
-        .showInInterface,
-        .specializeExtension,
-        .staticExclusiveOnly,
-        .testable,
-        .transparent,
-        .uiApplicationMain,
-        .unsafe,
-        .unsafeInheritExecutor,
-        .unsafeNoObjCTaggedPointer,
-        .unsafeNonEscapableResult,
-        .usableFromInline,
-        .used,
-        .warnUnqualifiedAccess,
-        .weakLinked:
-
-        return handle(self.generateSimpleDeclAttr(attribute: node, kind: attrKind))
+      case .AddressableSelf,
+        .AddressableForDependencies,
+        .AlwaysEmitConformanceMetadata,
+        .AlwaysEmitIntoClient,
+        .AtReasync,
+        .AtRethrows,
+        .Borrowed,
+        .CompilerInitialized,
+        .ConstVal,
+        .ConstInitialized,
+        .DynamicCallable,
+        .EagerMove,
+        .Exported,
+        .Nonexhaustive,
+        .DiscardableResult,
+        .DisfavoredOverload,
+        .DynamicMemberLookup,
+        .EmitAssemblyVisionRemarks,
+        .ExtractConstantsFromMembers,
+        .FixedLayout,
+        .Frozen,
+        .GKInspectable,
+        .GlobalActor,
+        .HasInitialValue,
+        .HasMissingDesignatedInitializers,
+        .HasStorage,
+        .IBAction,
+        .IBDesignable,
+        .IBInspectable,
+        .IBOutlet,
+        .IBSegueAction,
+        .ImplementationOnly,
+        .ImplicitSelfCapture,
+        .InheritsConvenienceInitializers,
+        .Inlinable,
+        .Isolated,
+        .LexicalLifetimes,
+        .LLDBDebuggerFunction,
+        .MainType,
+        .ManualOwnership,
+        .Marker,
+        .MoveOnly,
+        .NeverEmitIntoClient,
+        .NoAllocation,
+        .NoDerivative,
+        .NoEagerMove,
+        .NoExistentials,
+        .NoRuntime,
+        .NoImplicitCopy,
+        .NoLocks,
+        .NoMetadata,
+        .NoObjCBridging,
+        .NonEphemeral,
+        .NonEscapable,
+        .NonObjC,
+        .NonOverride,
+        .NSApplicationMain,
+        .NSCopying,
+        .NSManaged,
+        .ObjCMembers,
+        .ObjCNonLazyRealization,
+        .Preconcurrency,
+        .PreInverseGenerics,
+        .PropertyWrapper,
+        .RequiresStoredPropertyInits,
+        .ResultBuilder,
+        .Safe,
+        .Sendable,
+        .Sensitive,
+        .SPIOnly,
+        .ShowInInterface,
+        .SpecializeExtension,
+        .StaticExclusiveOnly,
+        .Testable,
+        .Transparent,
+        .UIApplicationMain,
+        .Unsafe,
+        .UnsafeInheritExecutor,
+        .UnsafeNoObjCTaggedPointer,
+        .UnsafeNonEscapableResult,
+        .UsableFromInline,
+        .Used,
+        .WarnUnqualifiedAccess,
+        .WeakLinked,
+        .UnsafeSelfDependentResult:
+
+        return handle(self.generateSimpleDeclAttr(attribute: node, kind: attrKind!))
 
       // Modifers.
-      case .accessControl:
+      case .AccessControl:
         // TODO: Diagnose and generateAccessControl().
         fatalError("unimplemented (access control modifier parsed as attributes)")
-      case .nonisolated:
+      case .Nonisolated:
         // TODO: Diagnose.
         return handle(self.generateNonisolatedAttr(attribute: node)?.asDeclAttribute)
-      case .referenceOwnership:
+      case .ReferenceOwnership:
         // TODO: Diagnose.
         return handle(self.generateReferenceOwnershipAttr(attribute: node, attrName: attrName)?.asDeclAttribute)
-      case .async,
-        .consuming,
-        .borrowing,
-        .actor,
-        .distributedActor,
-        .required,
-        .optional,
-        .lazy,
-        .dynamic,
-        .infix,
-        .prefix,
-        .postfix,
-        .legacyConsuming,
-        .mutating,
-        .nonMutating,
-        .convenience,
-        .override,
-        .indirect,
-        .final,
-        .knownToBeLocal,
-        .compileTimeLiteral:
+      case .InheritActorContext:
+        return handle(self.generateInheritActorContextAttr(attribute: node)?.asDeclAttribute)
+
+      case .Async,
+        .Consuming,
+        .Borrowing,
+        .Actor,
+        .DistributedActor,
+        .Required,
+        .Optional,
+        .Lazy,
+        .Dynamic,
+        .Infix,
+        .Prefix,
+        .Postfix,
+        .LegacyConsuming,
+        .Mutating,
+        .NonMutating,
+        .Convenience,
+        .Override,
+        .Indirect,
+        .Final,
+        .KnownToBeLocal,
+        .CompileTimeLiteral:
 
         // generateSimpleDeclAttr will diagnose and fix-it to change it to modifiers.
-        return handle(self.generateSimpleDeclAttr(attribute: node, kind: attrKind))
+        return handle(self.generateSimpleDeclAttr(attribute: node, kind: attrKind!))
 
       // 'RejectByParser', these attribute kind should not be parsed as built-in attributes.
-      case .rawDocComment,
-        .objCBridged,
-        .synthesizedProtocol,
-        .staticInitializeObjCMetadata,
-        .restatedObjCConformance,
-        .clangImporterSynthesizedType,
-        .forbidSerializingReference,
-        .custom,
-        .setterAccess:
-        assert(BridgedDeclAttribute.shouldBeRejectedByParser(attrKind))
+      case .RawDocComment,
+        .ObjCBridged,
+        .SynthesizedProtocol,
+        .StaticInitializeObjCMetadata,
+        .RestatedObjCConformance,
+        .ClangImporterSynthesizedType,
+        .ForbidSerializingReference,
+        .Custom,
+        .SetterAccess:
+        assert(BridgedDeclAttribute.shouldBeRejectedByParser(attrKind!))
         // Fall back to CustomAttr.
         break
 
@@ -358,33 +375,6 @@ extension ASTGenVisitor {
     return handle(self.generateCustomAttr(attribute: node)?.asDeclAttribute)
   }
 
-  /// E.g.:
-  ///   ```
-  ///   @execution(concurrent)
-  ///   @execution(caller)
-  ///   ```
-  func generateExecutionAttr(attribute node: AttributeSyntax) -> BridgedExecutionAttr? {
-    let behavior: BridgedExecutionKind? = self.generateSingleAttrOption(
-      attribute: node,
-      {
-        switch $0.rawText {
-        case "concurrent": return .concurrent
-        case "caller": return .caller
-        default: return nil
-        }
-      }
-    )
-    guard let behavior else {
-      return nil
-    }
-    return .createParsed(
-      self.ctx,
-      atLoc: self.generateSourceLoc(node.atSign),
-      range: self.generateAttrSourceRange(node),
-      behavior: behavior
-    )
-  }
-
   /// E.g.:
   ///   ```
   ///   @abi(func fn())
@@ -478,7 +468,7 @@ extension ASTGenVisitor {
       return nil
     }
 
-    let features = args.compactMap(in: self) { arg -> BridgedIdentifier? in
+    let features = args.compactMap(in: self) { arg -> Identifier? in
       guard arg.label == nil,
             let declNameExpr = arg.expression.as(DeclReferenceExprSyntax.self),
             declNameExpr.argumentNames == nil
@@ -556,20 +546,37 @@ extension ASTGenVisitor {
   /// E.g.:
   ///   ```
   ///   @_cdecl("c_function_name")
+  ///   @cdecl(c_function_name)
+  ///   @cdecl
   ///   ```
   func generateCDeclAttr(attribute node: AttributeSyntax) -> BridgedCDeclAttr? {
-    self.generateWithLabeledExprListArguments(attribute: node) { args in
-      guard let name = self.generateConsumingSimpleStringLiteralAttrOption(args: &args) else {
+    let attrName = node.attributeName.as(IdentifierTypeSyntax.self)?.name.text
+    let underscored = attrName?.hasPrefix("_") ?? false
+
+    var name: BridgedStringRef? = nil
+    if node.arguments != nil || underscored {
+      name = self.generateWithLabeledExprListArguments(attribute: node) {
+          args in
+        if underscored {
+          self.generateConsumingSimpleStringLiteralAttrOption(args: &args)
+        } else {
+           self.generateConsumingPlainIdentifierAttrOption(args: &args) {
+             return $0.rawText.bridged
+           }
+        }
+      }
+      guard name != nil else {
         return nil
       }
-
-      return .createParsed(
-        self.ctx,
-        atLoc: self.generateSourceLoc(node.atSign),
-        range: self.generateAttrSourceRange(node),
-        name: name
-      )
     }
+
+    return .createParsed(
+      self.ctx,
+      atLoc: self.generateSourceLoc(node.atSign),
+      range: self.generateAttrSourceRange(node),
+      name: name ?? "",
+      underscored: underscored
+    )
   }
 
   struct GeneratedDerivativeOriginalDecl {
@@ -664,7 +671,7 @@ extension ASTGenVisitor {
       return nil
     }
 
-    let accessorKind: BridgedAccessorKind?
+    let accessorKind: swift.AccessorKind?
     if let accessorToken = args.accessorSpecifier {
       accessorKind = self.generate(accessorSpecifier: accessorToken)
     } else {
@@ -779,13 +786,13 @@ extension ASTGenVisitor {
       return nil
     }
 
-    var visibility: BridgedAccessLevel = .none
+    var visibility: swift.AccessLevel?
     var metadata: BridgedStringRef? = nil
 
     while let arg = args.popFirst() {
       switch arg.label.rawText {
       case "visibility":
-        guard visibility == .none else {
+        guard visibility == nil else {
           // TODO: Diagnose duplicated 'visibility" arguments
           continue
         }
@@ -799,7 +806,7 @@ extension ASTGenVisitor {
         case .package: visibility = .package
         case .internal: visibility = .internal
         case .private: visibility = .private
-        case .fileprivate: visibility = .filePrivate
+        case .fileprivate: visibility = .fileprivate
         default:
           // TODO: Diagnose
           continue
@@ -833,7 +840,7 @@ extension ASTGenVisitor {
       atLoc: self.generateSourceLoc(node.atSign),
       range: self.generateAttrSourceRange(node),
       metadata: metadata ?? "",
-      accessLevel: visibility
+      accessLevel: visibility == nil ? .init() : .init(visibility!)
     )
   }
 
@@ -850,16 +857,16 @@ extension ASTGenVisitor {
       // TODO: Diagnose?
       return nil
     }
-    let effectKind: BridgedEffectsKind
+    let effectKind: swift.EffectsKind
     switch arguments.first!.rawText {
     case "readonly":
-      effectKind = .readOnly
+      effectKind = .readonly
     case "readnone":
-      effectKind = .readNone
+      effectKind = .readnone
     case "releasenone":
-      effectKind = .releaseNone
+      effectKind = .releasenone
     case "readwrite":
-      effectKind = .readWrite
+      effectKind = .readwrite
     default:
       effectKind = .custom
     }
@@ -919,7 +926,7 @@ extension ASTGenVisitor {
     // FIXME: SwiftParser should parse the argument as LabeledExprListArguments
     return self.generateWithLabeledExprListArguments(attribute: node) { args in
       // Exposure kind.
-      let kind: BridgedExposureKind? = self.generateConsumingPlainIdentifierAttrOption(args: &args) {
+      let kind: swift.ExposureKind? = self.generateConsumingPlainIdentifierAttrOption(args: &args) {
         switch $0.rawText {
         case "Cxx":
           return .cxx
@@ -962,10 +969,10 @@ extension ASTGenVisitor {
   ///   ```
   func generateExternAttr(attribute node: AttributeSyntax) -> BridgedExternAttr? {
     return self.generateWithLabeledExprListArguments(attribute: node) { args in
-      let kind: BridgedExternKind? = self.generateConsumingPlainIdentifierAttrOption(args: &args) {
+      let kind: swift.ExternKind? = self.generateConsumingPlainIdentifierAttrOption(args: &args) {
         switch $0.rawText {
         case "c":
-          return .C
+          return .c
         case "wasm":
           return .wasm
         default:
@@ -980,7 +987,7 @@ extension ASTGenVisitor {
       let moduleName: BridgedStringRef?
       let symbolName: BridgedStringRef?
       switch kind {
-      case .C:
+      case .c:
         moduleName = nil
         symbolName = args.isEmpty ? nil : self.generateConsumingSimpleStringLiteralAttrOption(args: &args)
       case .wasm:
@@ -1057,14 +1064,16 @@ extension ASTGenVisitor {
   ///   ```
   ///   @inline(never)
   ///   @inline(__always)
+  ///   @inline(always)
   ///   ```
   func generateInlineAttr(attribute node: AttributeSyntax) -> BridgedInlineAttr? {
-    let kind: BridgedInlineKind? = self.generateSingleAttrOption(
+    let kind: swift.InlineKind? = self.generateSingleAttrOption(
       attribute: node,
       {
         switch $0.rawText {
         case "never": return .never
-        case "__always": return .always
+        case "__always": return .alwaysUnderscored
+        case "always": return .always
         default: return nil
         }
       }
@@ -1104,8 +1113,11 @@ extension ASTGenVisitor {
       lifetimeDependenceKind = .inherit
       descriptorExpr = copyExpr.expression
     } else if let borrowExpr = node.as(BorrowExprSyntax.self) {
-      lifetimeDependenceKind = .scope
+      lifetimeDependenceKind = .borrow
       descriptorExpr = borrowExpr.expression
+    } else if let inoutExpr = node.as(InOutExprSyntax.self) {
+      lifetimeDependenceKind = .inout
+      descriptorExpr = inoutExpr.expression
     } else {
       lifetimeDependenceKind = .default
       descriptorExpr = node
@@ -1187,19 +1199,17 @@ extension ASTGenVisitor {
   ///   @lifetime(self)
   ///   ```
   func generateLifetimeAttr(attribute node: AttributeSyntax) -> BridgedLifetimeAttr? {
-    guard self.ctx.langOptsHasFeature(.LifetimeDependence) else {
-      // TODO: Diagnose
-      fatalError("@lifetime attribute requires 'LifetimeDependence' feature")
-    }
     guard let entry = self.generateLifetimeEntry(attribute: node) else {
       // TODO: Diagnose?
       return nil
     }
+
     return .createParsed(
       self.ctx,
       atLoc: self.generateSourceLoc(node.atSign),
       range: self.generateAttrSourceRange(node),
-      entry: entry
+      entry: entry,
+      isUnderscored: node.attributeName.as(IdentifierTypeSyntax.self)?.name.text == "_lifetime"
     )
   }
 
@@ -1267,7 +1277,7 @@ extension ASTGenVisitor {
       if let arg = arg.as(DeclReferenceExprSyntax.self) {
         name = self.generateDeclNameRef(declReferenceExpr: arg).name
       } else if arg.is(DiscardAssignmentExprSyntax.self) {
-        name = BridgedDeclNameRef.createParsed(.createIdentifier(self.ctx.getIdentifier("_")))
+        name = BridgedDeclNameRef.createParsed(.init(self.ctx.getIdentifier("_")))
       } else {
         // TODO: Diagnose
         fatalError("expected name")
@@ -1411,27 +1421,47 @@ extension ASTGenVisitor {
 
   // FIXME: This is a decl modifier
   func generateNonisolatedAttr(attribute node: AttributeSyntax) -> BridgedNonisolatedAttr? {
-    let isUnsafe = self.generateSingleAttrOption(
+    let modifier: swift.NonIsolatedModifier? = self.generateSingleAttrOption(
       attribute: node,
       {
         switch $0.rawText {
-        case "unsafe":
-          return true
-        default:
-          // FIXME: Diagnose.
-          return nil
+        case "unsafe": return .unsafe
+        case "nonsending": return .nonsending
+        default: return nil
+        }
+      },
+      valueIfOmitted: swift.NonIsolatedModifier.none
+    )
+    guard let modifier else {
+      return nil
+    }
+    return .createParsed(
+      self.ctx,
+      atLoc: self.generateSourceLoc(node.atSign),
+      range: self.generateAttrSourceRange(node),
+      modifier: modifier
+    )
+  }
+
+  func generateInheritActorContextAttr(attribute node: AttributeSyntax) -> BridgedInheritActorContextAttr? {
+    let modifier: swift.InheritActorContextModifier? = self.generateSingleAttrOption(
+      attribute: node,
+      {
+        switch $0.rawText {
+        case "always": return .always
+        default: return nil
         }
       },
-      valueIfOmitted: false
+      valueIfOmitted: swift.InheritActorContextModifier.none
     )
-    guard let isUnsafe else {
+    guard let modifier else {
       return nil
     }
     return .createParsed(
       self.ctx,
       atLoc: self.generateSourceLoc(node.atSign),
       range: self.generateAttrSourceRange(node),
-      isUnsafe: isUnsafe
+      modifier: modifier
     )
   }
 
@@ -1498,10 +1528,10 @@ extension ASTGenVisitor {
   ///   @_objcImplementation(CategoryName)
   ///   ```
   func generateObjCImplementationAttr(attribute node: AttributeSyntax) -> BridgedObjCImplementationAttr? {
-    let name: BridgedIdentifier? = self.generateSingleAttrOption(
+    let name: Identifier? = self.generateSingleAttrOption(
       attribute: node,
       self.generateIdentifier,
-      valueIfOmitted: BridgedIdentifier()
+      valueIfOmitted: Identifier()
     )
     guard let name else {
       // Should be diagnosed by `generateSingleAttrOption`.
@@ -1525,7 +1555,7 @@ extension ASTGenVisitor {
   ///   @_objcRuntimeName(RenamedClass)
   ///   ```
   func generateObjCRuntimeNameAttr(attribute node: AttributeSyntax) -> BridgedObjCRuntimeNameAttr? {
-    let name: BridgedIdentifier? = self.generateSingleAttrOption(attribute: node) {
+    let name: Identifier? = self.generateSingleAttrOption(attribute: node) {
       self.generateIdentifier($0)
     }
     guard let name else {
@@ -1630,7 +1660,7 @@ extension ASTGenVisitor {
   ///   ```
   func generateProjectedValuePropertyAttr(attribute node: AttributeSyntax) -> BridgedProjectedValuePropertyAttr? {
     // `@_dynamicReplacement` has special argument list syntax
-    let name = self.generateSingleAttrOption(attribute: node, { self.generateIdentifier($0) }, valueIfOmitted: BridgedIdentifier())
+    let name = self.generateSingleAttrOption(attribute: node, { self.generateIdentifier($0) }, valueIfOmitted: Identifier())
     guard let name else {
       // TODO: Diagnose.
       return nil
@@ -1648,7 +1678,7 @@ extension ASTGenVisitor {
     var node = node
 
     // Try value first.
-    let minusLoc: BridgedSourceLoc
+    let minusLoc: SourceLoc
     if let prefixExpr = node.as(PrefixOperatorExprSyntax.self),
       prefixExpr.operator.rawText == "-",
       prefixExpr.expression.is(IntegerLiteralExprSyntax.self) {
@@ -1871,7 +1901,40 @@ extension ASTGenVisitor {
 
   /// E.g.:
   ///   ```
-  ///   @_specialize(exporeted: true, T == Int)
+  ///   @specialized(T == Int)
+  ///   ```
+  func generateSpecializedAttr(attribute node: AttributeSyntax, attrName: SyntaxText) -> BridgedSpecializedAttr? {
+    guard
+      let arg = node.arguments?.as(SpecializedAttributeArgumentSyntax.self)
+    else {
+      // TODO: Diagnose
+      return nil
+    }
+    let exported: Bool? = nil
+    let kind: BridgedSpecializationKind? = nil
+    var whereClause: BridgedTrailingWhereClause? = nil
+    let targetFunction: BridgedDeclNameRef? = nil
+    let spiGroups: [Identifier] = []
+    let availableAttrs: [BridgedAvailableAttr] = []
+
+    whereClause = self.generate(genericWhereClause: arg.genericWhereClause)
+
+    return .createParsed(
+      self.ctx,
+      atLoc: self.generateSourceLoc(node.atSign),
+      range: self.generateAttrSourceRange(node),
+      whereClause: whereClause.asNullable,
+      exported: exported ?? false,
+      kind: kind ?? .full,
+      taretFunction: targetFunction ?? BridgedDeclNameRef(),
+      spiGroups: spiGroups.lazy.bridgedArray(in: self),
+      availableAttrs: availableAttrs.lazy.bridgedArray(in: self)
+    )
+  }
+
+  /// E.g.:
+  ///   ```
+  ///   @_specialize(exported: true, T == Int)
   ///   ```
   func generateSpecializeAttr(attribute node: AttributeSyntax, attrName: SyntaxText) -> BridgedSpecializeAttr? {
     guard
@@ -1880,18 +1943,17 @@ extension ASTGenVisitor {
       // TODO: Diagnose
       return nil
     }
-
     var exported: Bool?
     var kind: BridgedSpecializationKind? = nil
     var whereClause: BridgedTrailingWhereClause? = nil
     var targetFunction: BridgedDeclNameRef? = nil
-    var spiGroups: [BridgedIdentifier] = []
+    var spiGroups: [Identifier] = []
     var availableAttrs: [BridgedAvailableAttr] = []
 
     while let arg = args.popFirst() {
       switch arg {
       case .genericWhereClause(let arg):
-        whereClause =  self.generate(genericWhereClause: arg)
+        whereClause = self.generate(genericWhereClause: arg)
       case .specializeTargetFunctionArgument(let arg):
         if targetFunction != nil {
           // TODO: Diangose.
@@ -1971,7 +2033,7 @@ extension ASTGenVisitor {
   ///   @_spi(GroupName)
   ///   ```
   func generateSPIAccessControlAttr(attribute node: AttributeSyntax) -> BridgedSPIAccessControlAttr? {
-    let spiName: BridgedIdentifier? = self.generateSingleAttrOption(attribute: node) {
+    let spiName: Identifier? = self.generateSingleAttrOption(attribute: node) {
       self.generateIdentifier($0)
     }
     guard let spiName else {
@@ -2005,8 +2067,8 @@ extension ASTGenVisitor {
         case invalid
       }
       var argState = AttrArgumentState<Argument, UInt8>(.invalid)
-      var initializesProperties: [BridgedIdentifier] = []
-      var accessesProperties: [BridgedIdentifier] = []
+      var initializesProperties: [Identifier] = []
+      var accessesProperties: [Identifier] = []
 
       while let arg = args.popFirst() {
         // Label.
@@ -2031,7 +2093,7 @@ extension ASTGenVisitor {
         }
 
         // Value.
-        func generatePropertyName(expr node: ExprSyntax) -> BridgedIdentifier? {
+        func generatePropertyName(expr node: ExprSyntax) -> Identifier? {
           guard
             let node = node.as(DeclReferenceExprSyntax.self),
             node.argumentNames == nil
@@ -2072,7 +2134,7 @@ extension ASTGenVisitor {
   ///   @_swift_native_objc_runtime_base(FooBase)
   ///   ```
   func generateSwiftNativeObjCRuntimeBaseAttr(attribute node: AttributeSyntax) -> BridgedSwiftNativeObjCRuntimeBaseAttr? {
-    let name: BridgedIdentifier? = self.generateSingleAttrOption(attribute: node) {
+    let name: Identifier? = self.generateSingleAttrOption(attribute: node) {
       self.generateIdentifier($0)
     }
     guard let name else {
@@ -2169,7 +2231,7 @@ extension ASTGenVisitor {
   }
 
   func generateUnavailableInEmbeddedAttr(attribute node: AttributeSyntax) -> BridgedAvailableAttr? {
-    if ctx.langOptsHasFeature(.Embedded) {
+    if ctx.langOpts.hasFeature(.Embedded) {
       return BridgedAvailableAttr.createUnavailableInEmbedded(
         self.ctx,
         atLoc: self.generateSourceLoc(node.atSign),
@@ -2181,7 +2243,7 @@ extension ASTGenVisitor {
     }
   }
 
-  func generateSimpleDeclAttr(attribute node: AttributeSyntax, kind: BridgedDeclAttrKind) -> BridgedDeclAttribute? {
+  func generateSimpleDeclAttr(attribute node: AttributeSyntax, kind: swift.DeclAttrKind) -> BridgedDeclAttribute? {
     // TODO: Diagnose extraneous arguments.
     // TODO: Diagnose if `kind` is a modifier.
     return BridgedDeclAttribute.createSimple(
@@ -2231,9 +2293,9 @@ extension ASTGenVisitor {
     )
   }
 
-  func generateAttrSourceRange(_ node: AttributeSyntax) -> BridgedSourceRange {
+  func generateAttrSourceRange(_ node: AttributeSyntax) -> SourceRange {
     guard let firstNameTok = node.attributeName.firstToken(viewMode: .sourceAccurate) else {
-      return BridgedSourceRange()
+      return .init()
     }
     return self.generateSourceRange(start: firstNameTok, end: node.lastToken(viewMode: .sourceAccurate)!)
   }
@@ -2354,7 +2416,7 @@ extension ASTGenVisitor {
     case .private:
       return self.generateAccessControlAttr(declModifier: node, level: .private)
     case .fileprivate:
-      return self.generateAccessControlAttr(declModifier: node, level: .filePrivate)
+      return self.generateAccessControlAttr(declModifier: node, level: .fileprivate)
     case .internal:
       return self.generateAccessControlAttr(declModifier: node, level: .internal)
     case .package:
@@ -2369,20 +2431,20 @@ extension ASTGenVisitor {
       return self.generateReferenceOwnershipAttr(declModifier: node)?.asDeclAttribute
     default:
       // Other modifiers are all "simple" attributes.
-      let kind = BridgedDeclAttrKind(from: node.name.rawText.bridged)
-      guard kind != .none else {
+      let kind = BridgedOptionalDeclAttrKind(from: node.name.rawText.bridged)
+      guard kind.hasValue else {
         // TODO: Diagnose.
         fatalError("(compiler bug) unknown decl modifier")
       }
-      if !BridgedDeclAttribute.isDeclModifier(kind) {
+      if !BridgedDeclAttribute.isDeclModifier(kind.value) {
         // TODO: Diagnose.
         fatalError("(compiler bug) decl attribute was parsed as a modifier")
       }
-      return self.generateSimpleDeclAttr(declModifier: node, kind: kind)
+      return self.generateSimpleDeclAttr(declModifier: node, kind: kind.value)
     }
   }
 
-  func generateAccessControlAttr(declModifier node: DeclModifierSyntax, level: BridgedAccessLevel)
+  func generateAccessControlAttr(declModifier node: DeclModifierSyntax, level: swift.AccessLevel)
     -> BridgedDeclAttribute?
   {
     if let detail = node.detail {
@@ -2405,12 +2467,14 @@ extension ASTGenVisitor {
   }
 
   func generateNonisolatedAttr(declModifier node: DeclModifierSyntax) -> BridgedNonisolatedAttr? {
-    let isUnsafe: Bool
+    let modifier: swift.NonIsolatedModifier
     switch node.detail?.detail.rawText {
     case "unsafe":
-      isUnsafe = true
+      modifier = .unsafe
+    case "nonsending":
+      modifier = .nonsending
     case nil:
-      isUnsafe = false
+      modifier = .none
     case let text?:
       // TODO: Diagnose
       _ = text
@@ -2421,7 +2485,7 @@ extension ASTGenVisitor {
       self.ctx,
       atLoc: nil,
       range: self.generateSourceRange(node),
-      isUnsafe: isUnsafe
+      modifier: modifier
     )
   }
 
@@ -2463,7 +2527,7 @@ extension ASTGenVisitor {
     )
   }
 
-  func generateSimpleDeclAttr(declModifier node: DeclModifierSyntax, kind: BridgedDeclAttrKind) -> BridgedDeclAttribute? {
+  func generateSimpleDeclAttr(declModifier node: DeclModifierSyntax, kind: swift.DeclAttrKind) -> BridgedDeclAttribute? {
     // TODO: Diagnose non-modifier kind? Parser shouldn't accept them, though.
     // Simple modifier don't accept any detail.
     precondition(node.detail == nil, "decl modifiers can't have arguments except access control modifiers")
diff --git a/lib/ASTGen/Sources/ASTGen/Decls.swift b/lib/ASTGen/Sources/ASTGen/Decls.swift
index 62e275dac7d55..900eb1ab440be 100644
--- a/lib/ASTGen/Sources/ASTGen/Decls.swift
+++ b/lib/ASTGen/Sources/ASTGen/Decls.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -67,12 +67,17 @@ extension ASTGenVisitor {
       return self.generate(subscriptDecl: node).asDecl
     case .typeAliasDecl(let node):
       return self.generate(typeAliasDecl: node)?.asDecl
+    case .unexpectedCodeDecl:
+      // Ignore unexpected code.
+      return nil
     case .variableDecl(let node):
       return self.generate(variableDecl: node)
+    case .usingDecl(let node):
+      return self.generate(usingDecl: node)?.asDecl
     }
   }
 
-  func generateIdentifierDeclNameAndLoc(_ node: TokenSyntax) -> (identifier: BridgedIdentifier, sourceLoc: BridgedSourceLoc)? {
+  func generateIdentifierDeclNameAndLoc(_ node: TokenSyntax) -> (identifier: Identifier, sourceLoc: SourceLoc)? {
     guard node.presence == .present else {
       return nil
     }
@@ -373,7 +378,7 @@ extension ASTGenVisitor {
 // MARK: - AbstractStorageDecl
 
 extension ASTGenVisitor {
-  func generate(accessorSpecifier specifier: TokenSyntax) -> BridgedAccessorKind? {
+  func generate(accessorSpecifier specifier: TokenSyntax) -> swift.AccessorKind? {
     switch specifier.keywordKind {
     case .get:
       return .get
@@ -384,21 +389,21 @@ extension ASTGenVisitor {
     case .willSet:
       return .willSet
     case .unsafeAddress:
-      return .address
+      return .unsafeAddress
     case .unsafeMutableAddress:
-      return .mutableAddress
+      return .unsafeMutableAddress
     case ._read:
-      return .read
+      return ._read
     case ._modify:
-      return .modify
+      return ._modify
     case .`init`:
-      return .`init`
+      return .Init
     case .read:
-      precondition(ctx.langOptsHasFeature(.CoroutineAccessors), "(compiler bug) 'read' accessor should only be parsed with 'CoroutineAccessors' feature")
-      return .read2
+      precondition(ctx.langOpts.hasFeature(.CoroutineAccessors), "(compiler bug) 'read' accessor should only be parsed with 'CoroutineAccessors' feature")
+      return .read
     case .modify:
-      precondition(ctx.langOptsHasFeature(.CoroutineAccessors), "(compiler bug) 'modify' accessor should only be parsed with 'CoroutineAccessors' feature")
-      return .modify2
+      precondition(ctx.langOpts.hasFeature(.CoroutineAccessors), "(compiler bug) 'modify' accessor should only be parsed with 'CoroutineAccessors' feature")
+      return .modify
     default:
       self.diagnose(.unknownAccessorSpecifier(specifier))
       return nil
@@ -667,9 +672,9 @@ extension ASTGenVisitor {
 extension ASTGenVisitor {
   struct GeneratedFunctionSignature {
     var parameterList: BridgedParameterList
-    var asyncLoc: BridgedSourceLoc
+    var asyncLoc: SourceLoc
     var isReasync: Bool
-    var throwsLoc: BridgedSourceLoc
+    var throwsLoc: SourceLoc
     var isRethrows: Bool
     var thrownType: BridgedTypeRepr?
     var returnType: BridgedTypeRepr?
@@ -704,7 +709,7 @@ extension ASTGenVisitor {
     }
     let signature = self.generate(
       functionSignature: node.signature,
-      for: name.isOperator ? .operator : .function
+      for: name.isOperator() ? .operator : .function
     )
 
     let decl = BridgedFuncDecl.createParsed(
@@ -724,10 +729,10 @@ extension ASTGenVisitor {
       genericWhereClause: self.generate(genericWhereClause: node.genericWhereClause)
     )
     if signature.isReasync {
-      attrs.attributes.add(BridgedDeclAttribute.createSimple(self.ctx, kind: .reasync, atLoc: nil, nameLoc: signature.asyncLoc))
+      attrs.attributes.add(BridgedDeclAttribute.createSimple(self.ctx, kind: .Reasync, atLoc: nil, nameLoc: signature.asyncLoc))
     }
     if signature.isRethrows {
-      attrs.attributes.add(BridgedDeclAttribute.createSimple(self.ctx, kind: .rethrows, atLoc: nil, nameLoc: signature.throwsLoc))
+      attrs.attributes.add(BridgedDeclAttribute.createSimple(self.ctx, kind: .Rethrows, atLoc: nil, nameLoc: signature.throwsLoc))
     }
     decl.asDecl.attachParsedAttrs(attrs.attributes)
 
@@ -761,10 +766,10 @@ extension ASTGenVisitor {
       genericWhereClause: self.generate(genericWhereClause: node.genericWhereClause)
     )
     if signature.isReasync {
-      attrs.attributes.add(BridgedDeclAttribute.createSimple(self.ctx, kind: .reasync, atLoc: nil, nameLoc: signature.asyncLoc))
+      attrs.attributes.add(BridgedDeclAttribute.createSimple(self.ctx, kind: .Reasync, atLoc: nil, nameLoc: signature.asyncLoc))
     }
     if signature.isRethrows {
-      attrs.attributes.add(BridgedDeclAttribute.createSimple(self.ctx, kind: .rethrows, atLoc: nil, nameLoc: signature.throwsLoc))
+      attrs.attributes.add(BridgedDeclAttribute.createSimple(self.ctx, kind: .Rethrows, atLoc: nil, nameLoc: signature.throwsLoc))
     }
     decl.asDecl.attachParsedAttrs(attrs.attributes)
     
@@ -925,7 +930,7 @@ extension ASTGenVisitor {
 
 // MARK: - PrecedenceGroupDecl
 
-extension BridgedAssociativity {
+extension swift.Associativity {
   fileprivate init?(from keyword: Keyword?) {
     switch keyword {
     case .none?: self = .none
@@ -989,9 +994,9 @@ extension ASTGenVisitor {
       }
     }
 
-    let associativityValue: BridgedAssociativity
+    let associativityValue: swift.Associativity
     if let token = body.associativity?.value {
-      if let value = BridgedAssociativity(from: token.keywordKind) {
+      if let value = swift.Associativity(from: token.keywordKind) {
         associativityValue = value
       } else {
         self.diagnose(.unexpectedTokenKind(token: token))
@@ -1083,6 +1088,37 @@ extension ASTGenVisitor {
   }
 }
 
+extension ASTGenVisitor {
+  func generate(usingDecl node: UsingDeclSyntax) -> BridgedUsingDecl? {
+    var specifier: BridgedUsingSpecifier? = nil
+
+    switch node.specifier {
+    case .attribute(let attr):
+      if let identifier = attr.attributeName.as(IdentifierTypeSyntax.self),
+         identifier.name.tokenKind == .identifier("MainActor") {
+        specifier = .mainActor
+      }
+    case .modifier(let modifier):
+      if case .identifier("nonisolated") = modifier.tokenKind {
+        specifier = .nonisolated
+      }
+    }
+
+    guard let specifier else {
+      self.diagnose(.invalidDefaultIsolationSpecifier(node.specifier))
+      return nil
+    }
+
+    return BridgedUsingDecl.createParsed(
+      self.ctx,
+      declContext: self.declContext,
+      usingKeywordLoc: self.generateSourceLoc(node.usingKeyword),
+      specifierLoc: self.generateSourceLoc(node.specifier),
+      specifier: specifier
+    )
+  }
+}
+
 extension ASTGenVisitor {
   func generate(memberBlockItem node: MemberBlockItemSyntax) -> BridgedDecl? {
     if let node = node.decl.as(MacroExpansionDeclSyntax.self) {
diff --git a/lib/ASTGen/Sources/ASTGen/Diagnostics.swift b/lib/ASTGen/Sources/ASTGen/Diagnostics.swift
index 3d578d51d2456..ff78907df0f93 100644
--- a/lib/ASTGen/Sources/ASTGen/Diagnostics.swift
+++ b/lib/ASTGen/Sources/ASTGen/Diagnostics.swift
@@ -146,6 +146,13 @@ extension ASTGenDiagnostic {
       message: "expressions are not allowed at the top level"
     )
   }
+
+  static func invalidDefaultIsolationSpecifier(_ specifier: some SyntaxProtocol) -> Self {
+    Self(
+      node: specifier,
+      message: "default isolation can only be set to '@MainActor' or 'nonisolated'"
+    )
+  }
 }
 
 /// DeclAttributes diagnostics
diff --git a/lib/ASTGen/Sources/ASTGen/DiagnosticsBridge.swift b/lib/ASTGen/Sources/ASTGen/DiagnosticsBridge.swift
index 6d733229c2e1a..45e39aa634b8e 100644
--- a/lib/ASTGen/Sources/ASTGen/DiagnosticsBridge.swift
+++ b/lib/ASTGen/Sources/ASTGen/DiagnosticsBridge.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -33,15 +33,15 @@ fileprivate func emitDiagnosticParts(
   // Map severity
   let bridgedSeverity = severity.bridged
 
-  func bridgedSourceLoc(at position: AbsolutePosition) -> BridgedSourceLoc {
-    return BridgedSourceLoc(at: position.advanced(by: offset), in: sourceFileBuffer)
+  func sourceLoc(at position: AbsolutePosition) -> SourceLoc {
+    return SourceLoc(at: position.advanced(by: offset), in: sourceFileBuffer)
   }
 
   // Emit the diagnostic
   var mutableMessage = message
   let diag = mutableMessage.withBridgedString { bridgedMessage in
     BridgedDiagnostic(
-      at: bridgedSourceLoc(at: position),
+      at: sourceLoc(at: position),
       message: bridgedMessage,
       severity: bridgedSeverity,
       engine: diagnosticEngine
@@ -51,8 +51,8 @@ fileprivate func emitDiagnosticParts(
   // Emit highlights
   for highlight in highlights {
     diag.highlight(
-      start: bridgedSourceLoc(at: highlight.positionAfterSkippingLeadingTrivia),
-      end: bridgedSourceLoc(at: highlight.endPositionBeforeTrailingTrivia)
+      start: sourceLoc(at: highlight.positionAfterSkippingLeadingTrivia),
+      end: sourceLoc(at: highlight.endPositionBeforeTrailingTrivia)
     )
   }
 
@@ -61,8 +61,8 @@ fileprivate func emitDiagnosticParts(
     var newText: String = edit.replacement
     newText.withBridgedString { bridgedMessage in
       diag.fixItReplace(
-        start: bridgedSourceLoc(at: edit.range.lowerBound),
-        end: bridgedSourceLoc(at: edit.range.upperBound),
+        start: sourceLoc(at: edit.range.lowerBound),
+        end: sourceLoc(at: edit.range.upperBound),
         replacement: bridgedMessage
       )
     }
@@ -120,7 +120,7 @@ public func emitDiagnostic(
 }
 
 extension DiagnosticSeverity {
-  public var bridged: BridgedDiagnosticSeverity {
+  public var bridged: swift.DiagnosticKind {
     switch self {
     case .error: return .error
     case .note: return .note
@@ -177,10 +177,9 @@ fileprivate struct SimpleDiagnostic: DiagnosticMessage {
   }
 }
 
-extension BridgedDiagnosticSeverity {
+extension swift.DiagnosticKind {
   var asSeverity: DiagnosticSeverity {
     switch self {
-    case .fatalError: return .error
     case .error: return .error
     case .warning: return .warning
     case .remark: return .remark
@@ -250,11 +249,11 @@ public func addQueuedDiagnostic(
   queuedDiagnosticsPtr: UnsafeMutableRawPointer,
   perFrontendDiagnosticStatePtr: UnsafeMutableRawPointer,
   text: BridgedStringRef,
-  severity: BridgedDiagnosticSeverity,
-  cLoc: BridgedSourceLoc,
+  severity: swift.DiagnosticKind,
+  loc: SourceLoc,
   categoryName: BridgedStringRef,
   documentationPath: BridgedStringRef,
-  highlightRangesPtr: UnsafePointer<BridgedCharSourceRange>?,
+  highlightRangesPtr: UnsafePointer<CharSourceRange>?,
   numHighlightRanges: Int,
   fixItsUntyped: BridgedArrayRef
 ) {
@@ -266,7 +265,7 @@ public func addQueuedDiagnostic(
     to: PerFrontendDiagnosticState.self
   )
 
-  guard let rawPosition = cLoc.getOpaquePointerValue() else {
+  guard let rawPosition = loc.raw else {
     return
   }
 
@@ -308,7 +307,7 @@ public func addQueuedDiagnostic(
 
   // Map the highlights.
   var highlights: [Syntax] = []
-  let highlightRanges = UnsafeBufferPointer<BridgedCharSourceRange>(
+  let highlightRanges = UnsafeBufferPointer<CharSourceRange>(
     start: highlightRangesPtr,
     count: numHighlightRanges
   )
@@ -316,9 +315,7 @@ public func addQueuedDiagnostic(
     let range = highlightRanges[index]
 
     // Make sure both the start and the end land within this source file.
-    guard let start = range.start.getOpaquePointerValue(),
-      let end = range.start.advanced(by: range.byteLength).getOpaquePointerValue()
-    else {
+    guard let start = range.start.raw, let end = range.end.raw else {
       continue
     }
 
@@ -387,9 +384,7 @@ public func addQueuedDiagnostic(
   let fixItChanges: [FixIt.Change] = fixItsUntyped.withElements(ofType: BridgedFixIt.self) { fixIts in
     fixIts.compactMap { fixIt in
       guard let startPos = sourceFile.position(of: fixIt.replacementRange.start),
-            let endPos = sourceFile.position(
-              of: fixIt.replacementRange.start.advanced(
-                by: fixIt.replacementRange.byteLength)) else {
+            let endPos = sourceFile.position(of: fixIt.replacementRange.end) else {
         return nil
       }
 
@@ -425,6 +420,60 @@ public func addQueuedDiagnostic(
   queuedDiagnostics.pointee.grouped.addDiagnostic(diagnostic)
 }
 
+/// Render a single diagnostic that has no source location information.
+@_cdecl("swift_ASTGen_renderSingleDiagnostic")
+public func renderSingleDiagnostic(
+  perFrontendDiagnosticStatePtr: UnsafeMutableRawPointer,
+  text: BridgedStringRef,
+  severity: swift.DiagnosticKind,
+  categoryName: BridgedStringRef,
+  documentationPath: BridgedStringRef,
+  colorize: Int,
+  renderedStringOutPtr: UnsafeMutablePointer<BridgedStringRef>
+) {
+  let diagnosticState = perFrontendDiagnosticStatePtr.assumingMemoryBound(
+    to: PerFrontendDiagnosticState.self
+  )
+
+  let documentationPath = String(bridged: documentationPath)
+  let documentationURL: String? = if !documentationPath.isEmpty {
+      // If this looks doesn't look like a URL, prepend file://.
+      documentationPath.looksLikeURL ? documentationPath : "file://\(documentationPath)"
+    } else {
+      nil
+    }
+
+  let categoryName = String(bridged: categoryName)
+  // If the data comes from serialized diagnostics, it's possible that
+  // the category name is empty because StringRef() is serialized into
+  // an empty string.
+  let category: DiagnosticCategory? = if !categoryName.isEmpty {
+      DiagnosticCategory(
+        name: categoryName,
+        documentationURL: documentationURL
+      )
+    } else {
+      nil
+    }
+
+  // Note that we referenced this category.
+  if let category {
+    diagnosticState.pointee.referencedCategories.insert(category)
+  }
+
+  let formatter = DiagnosticsFormatter(colorize: colorize != 0)
+
+  let renderedStr = formatter.formattedMessage(
+    SimpleDiagnostic(
+      message: String(bridged: text),
+      severity: severity.asSeverity,
+      category: category
+    )
+  )
+
+  renderedStringOutPtr.pointee = allocateBridgedString(renderedStr)
+}
+
 /// Render the queued diagnostics into a UTF-8 string.
 @_cdecl("swift_ASTGen_renderQueuedDiagnostics")
 public func renderQueuedDiagnostics(
diff --git a/lib/ASTGen/Sources/ASTGen/EmbeddedSupport.swift b/lib/ASTGen/Sources/ASTGen/EmbeddedSupport.swift
new file mode 100644
index 0000000000000..0dfc9fa768fbe
--- /dev/null
+++ b/lib/ASTGen/Sources/ASTGen/EmbeddedSupport.swift
@@ -0,0 +1,142 @@
+//===--- EmbeddedSupport.swift --------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import ASTBridging
+import BasicBridging
+import SwiftIfConfig
+import SwiftSyntax
+
+extension ExportedSourceFile {
+  /// Return the configured regions for this source file.
+  mutating func configuredRegionsIfEmbedded(astContext: BridgedASTContext) -> ConfiguredRegions {
+    if let _configuredRegionsIfEmbedded {
+      return _configuredRegionsIfEmbedded
+    }
+
+    // Ensure that we've already computed the configured regions, which can
+    // emit diagnostics.
+    _ = configuredRegions(astContext: astContext)
+
+    let configuration = EmbeddedBuildConfiguration(
+      ctx: astContext,
+      sourceBuffer: buffer
+    )
+
+    let regions = syntax.configuredRegions(in: configuration)
+    _configuredRegionsIfEmbedded = regions
+    return regions
+  }
+}
+
+/// Determine whether the given source location is active when this source
+/// file is compiled in Embedded Swift.
+@_cdecl("swift_ASTGen_activeInEmbeddedSwift")
+public func activeInEmbeddedSwift(
+  astContext: BridgedASTContext,
+  sourceFilePtr: UnsafeMutableRawPointer,
+  at location: SourceLoc
+) -> Int {
+  guard let token = findToken(
+    in: UnsafeRawPointer(sourceFilePtr),
+    at: location.raw?.assumingMemoryBound(to: UInt8.self)
+  ) else {
+    return 0
+  }
+
+  let sourceFile = sourceFilePtr.assumingMemoryBound(to: ExportedSourceFile.self)
+  let regions = sourceFile.pointee.configuredRegionsIfEmbedded(astContext: astContext)
+  return regions.isActive(token) == .active ? 1 : 0
+}
+
+/// A build configuration that is a thin shim over the
+/// CompilerBuildConfiguration that enables the Embedded language feature,
+/// allowing the compiler to determine whether code we're in will be available
+/// in an embedded context or not.
+struct EmbeddedBuildConfiguration: BuildConfiguration {
+  let configuration: CompilerBuildConfiguration
+
+  init(ctx: BridgedASTContext, sourceBuffer: UnsafeBufferPointer<UInt8>) {
+    self.configuration = .init(ctx: ctx, sourceBuffer: sourceBuffer)
+  }
+
+  func isCustomConditionSet(name: String) -> Bool {
+    // $Embedded is set when building Embedded Swift
+    if name == "$Embedded" {
+      return true
+    }
+
+    return configuration.isCustomConditionSet(name: name)
+  }
+
+  func hasFeature(name: String) -> Bool {
+    // The "Embedded" feature is set when building Embedded Swift.
+    if name == "Embedded" {
+      return true
+    }
+
+    return configuration.hasFeature(name: name)
+  }
+
+  func hasAttribute(name: String) -> Bool {
+    return configuration.hasAttribute(name: name)
+  }
+
+  func canImport(
+    importPath: [(TokenSyntax, String)],
+    version: CanImportVersion
+  ) throws -> Bool {
+    // FIXME: We would prefer to call the underlying canImport in some kind of
+    // "replay" mode that is not allowed to produce diagnostics or trigger any
+    // loading.
+    return false
+  }
+
+  func isActiveTargetOS(name: String) -> Bool {
+    return configuration.isActiveTargetOS(name: name)
+  }
+
+  func isActiveTargetArchitecture(name: String) -> Bool {
+    return configuration.isActiveTargetArchitecture(name: name)
+  }
+
+  func isActiveTargetEnvironment(name: String) -> Bool {
+    return configuration.isActiveTargetEnvironment(name: name)
+  }
+
+  func isActiveTargetRuntime(name: String) throws -> Bool {
+    return try configuration.isActiveTargetRuntime(name: name)
+  }
+
+  func isActiveTargetPointerAuthentication(name: String) -> Bool {
+    return configuration.isActiveTargetPointerAuthentication(name: name)
+  }
+
+  var targetPointerBitWidth: Int {
+    return configuration.targetPointerBitWidth
+  }
+
+  var targetAtomicBitWidths: [Int] {
+    return configuration.targetAtomicBitWidths
+  }
+
+  var endianness: Endianness {
+    return configuration.endianness
+  }
+
+  var languageVersion: VersionTuple {
+    return configuration.languageVersion
+  }
+
+  var compilerVersion: VersionTuple {
+    return configuration.compilerVersion
+  }
+}
diff --git a/lib/ASTGen/Sources/ASTGen/Exprs.swift b/lib/ASTGen/Sources/ASTGen/Exprs.swift
index f7d774298bbf2..c30c23e06fc50 100644
--- a/lib/ASTGen/Sources/ASTGen/Exprs.swift
+++ b/lib/ASTGen/Sources/ASTGen/Exprs.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 import ASTBridging
+import swiftBasicSwift
 import SwiftDiagnostics
 @_spi(Compiler) import SwiftParser
 @_spi(ExperimentalLanguageFeatures) @_spi(RawSyntax) import SwiftSyntax
@@ -167,8 +168,8 @@ extension ASTGenVisitor {
   }
 
   func generate(arrowExpr node: ArrowExprSyntax) -> BridgedArrowExpr {
-    let asyncLoc: BridgedSourceLoc
-    let throwsLoc: BridgedSourceLoc
+    let asyncLoc: SourceLoc
+    let throwsLoc: SourceLoc
     let thrownTypeExpr: BridgedNullableExpr
 
     if let effectSpecifiers = node.effectSpecifiers {
@@ -285,7 +286,7 @@ extension ASTGenVisitor {
       fatalError("invalid ownership")
     }
     let nameAndLoc = self.generateIdentifierAndSourceLoc(node.name)
-    let equalLoc: BridgedSourceLoc
+    let equalLoc: SourceLoc
     let initExpr: BridgedExpr
     if let initializer = node.initializer {
       equalLoc = self.generateSourceLoc(initializer.equal)
@@ -309,7 +310,7 @@ extension ASTGenVisitor {
 
     // If we captured something under the name "self", remember that.
     if nameAndLoc.identifier == ctx.id_self {
-      capturedSelfDecl = entry.varDecl
+      capturedSelfDecl = entry.getVarDecl()
     }
 
     return entry
@@ -317,16 +318,16 @@ extension ASTGenVisitor {
 
   struct GeneratedClosureSignature {
     var attributes: BridgedDeclAttributes = BridgedDeclAttributes()
-    var bracketRange: BridgedSourceRange = BridgedSourceRange(start: nil, end: nil)
+    var bracketRange: SourceRange = .init()
     var captureList: BridgedArrayRef = BridgedArrayRef()
     var capturedSelfDecl: BridgedVarDecl? = nil
     var params: BridgedParameterList? = nil
-    var asyncLoc: BridgedSourceLoc = nil
-    var throwsLoc: BridgedSourceLoc = nil
+    var asyncLoc: SourceLoc = nil
+    var throwsLoc: SourceLoc = nil
     var thrownType: BridgedTypeRepr? = nil
-    var arrowLoc: BridgedSourceLoc = nil
+    var arrowLoc: SourceLoc = nil
     var explicitResultType: BridgedTypeRepr? = nil
-    var inLoc: BridgedSourceLoc = nil
+    var inLoc: SourceLoc = nil
   }
 
   func generate(closureExpr node: ClosureExprSyntax) -> BridgedExpr {
@@ -443,8 +444,8 @@ extension ASTGenVisitor {
       let normalArgs = labeledExprList.lazy.map({ elem in
         let labelInfo = elem.label.map(self.generateIdentifierAndSourceLoc(_:))
         return BridgedCallArgument(
-          labelLoc: labelInfo?.sourceLoc ?? BridgedSourceLoc(),
-          label: labelInfo?.identifier ?? BridgedIdentifier(),
+          labelLoc: labelInfo?.sourceLoc ?? SourceLoc(),
+          label: labelInfo?.identifier ?? Identifier(),
           argExpr: self.generate(expr: elem.expression)
         )
       })
@@ -520,7 +521,7 @@ extension ASTGenVisitor {
   func generateDeclNameRef(declReferenceExpr node: DeclReferenceExprSyntax) -> (
     name: BridgedDeclNameRef, loc: BridgedDeclNameLoc
   ) {
-    let baseName: BridgedDeclBaseName
+    let baseName: DeclBaseName
     switch node.baseName.keywordKind {
     case .`init`:
       baseName = .createConstructor()
@@ -529,7 +530,7 @@ extension ASTGenVisitor {
     case .subscript:
       baseName = .createSubscript()
     default:
-      baseName = .createIdentifier(self.generateIdentifier(node.baseName))
+      baseName = .init(self.generateIdentifier(node.baseName))
     }
     let baseNameLoc = self.generateSourceLoc(node.baseName)
 
@@ -686,7 +687,7 @@ extension ASTGenVisitor {
       if prop.declName.baseName.presence == .missing {
         return BridgedErrorExpr.create(
           self.ctx,
-          loc: BridgedSourceRange(start: dotLoc, end: dotLoc)
+          loc: .init(start: dotLoc)
         ).asExpr
       } else if prop.declName.baseName.keywordKind == .`self` {
         // TODO: Diagnose if there's arguments
@@ -815,12 +816,12 @@ extension ASTGenVisitor {
   }
 
   struct FreestandingMacroExpansionInfo {
-    var poundLoc: BridgedSourceLoc
+    var poundLoc: SourceLoc
     var macroNameRef: BridgedDeclNameRef
     var macroNameLoc: BridgedDeclNameLoc
-    var leftAngleLoc: BridgedSourceLoc
+    var leftAngleLoc: SourceLoc
     var genericArgs: BridgedArrayRef
-    var rightAngleLoc: BridgedSourceLoc
+    var rightAngleLoc: SourceLoc
     var arguments: BridgedNullableArgumentList
   }
 
@@ -828,9 +829,9 @@ extension ASTGenVisitor {
     let poundLoc = self.generateSourceLoc(node.pound)
     let nameLoc = self.generateIdentifierAndSourceLoc(node.macroName)
 
-    let leftAngleLoc: BridgedSourceLoc
+    let leftAngleLoc: SourceLoc
     let genericArgs: [BridgedTypeRepr]
-    let rightAngleLoc: BridgedSourceLoc
+    let rightAngleLoc: SourceLoc
     if let generics = node.genericArgumentClause {
       leftAngleLoc = self.generateSourceLoc(generics.leftAngle)
       genericArgs = generics.arguments.map {
@@ -858,7 +859,7 @@ extension ASTGenVisitor {
 
     return FreestandingMacroExpansionInfo(
       poundLoc: poundLoc,
-      macroNameRef: .createParsed(.createIdentifier(nameLoc.identifier)),
+      macroNameRef: .createParsed(.init(nameLoc.identifier)),
       macroNameLoc: .createParsed(nameLoc.sourceLoc),
       leftAngleLoc: leftAngleLoc,
       genericArgs: genericArgs.lazy.bridgedArray(in: self),
@@ -955,7 +956,7 @@ extension ASTGenVisitor {
     let loc = self.generateSourceLoc(node.previousToken(viewMode: .sourceAccurate))
     return BridgedErrorExpr.create(
       self.ctx,
-      loc: BridgedSourceRange(start: loc, end: loc)
+      loc: .init(start: loc)
     ).asExpr
   }
 
@@ -1332,7 +1333,7 @@ extension ASTGenVisitor {
 
     return .createParsed(
       self.ctx,
-      name: .createParsed(.createIdentifier(name)),
+      name: .createParsed(.init(name)),
       kind: kind,
       loc: .createParsed(nameLoc)
     );
diff --git a/lib/ASTGen/Sources/ASTGen/Generics.swift b/lib/ASTGen/Sources/ASTGen/Generics.swift
index 341c73fe206de..b5a5d1326d90f 100644
--- a/lib/ASTGen/Sources/ASTGen/Generics.swift
+++ b/lib/ASTGen/Sources/ASTGen/Generics.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -41,13 +41,14 @@ extension ASTGenVisitor {
       preconditionFailure("Node not part of the parent?")
     }
 
-    var paramKind: BridgedGenericTypeParamKind = .type
-
-    if node.specifier?.tokenKind == .keyword(.each) {
-      paramKind = .pack
-    } else if node.specifier?.tokenKind == .keyword(.let) {
-      paramKind = .value
-    }
+    let paramKind: swift.GenericTypeParamKind =
+      if node.specifier?.tokenKind == .keyword(.each) {
+        .pack
+      } else if node.specifier?.tokenKind == .keyword(.let) {
+        .value
+      } else {
+        .type
+      }
 
     return .createParsed(
       self.ctx,
@@ -188,7 +189,7 @@ extension ASTGenVisitor {
   }
 
   func generateIntegerType(expr node: ExprSyntax) -> BridgedIntegerTypeRepr {
-    var minusLoc = BridgedSourceLoc()
+    var minusLoc = SourceLoc()
     let literalExpr: IntegerLiteralExprSyntax
 
     // The only expressions generic argument types support right now are
diff --git a/lib/ASTGen/Sources/ASTGen/LexicalLookup.swift b/lib/ASTGen/Sources/ASTGen/LexicalLookup.swift
index 7315ce6c1b4c8..af7099fa2d645 100644
--- a/lib/ASTGen/Sources/ASTGen/LexicalLookup.swift
+++ b/lib/ASTGen/Sources/ASTGen/LexicalLookup.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -40,7 +40,7 @@ private let rowCharWidth: Int = 30
 public func unqualifiedLookup(
   sourceFilePtr: UnsafeMutableRawPointer,
   astContext: BridgedASTContext,
-  lookupAt: BridgedSourceLoc,
+  lookupAt: SourceLoc,
   finishInSequentialScope: Bool,
   astScopeResultRef: BridgedArrayRef
 ) -> Bool {
@@ -612,7 +612,7 @@ struct ConsumedLookupResultFlag: OptionSet, Hashable {
   static let ignoreNextFromHere = ConsumedLookupResultFlag(rawValue: 1 << 6)
 }
 
-extension SourceLocation {
+extension SwiftSyntax.SourceLocation {
   fileprivate var lineWithColumn: String {
     return "\(line):\(column)"
   }
diff --git a/lib/ASTGen/Sources/ASTGen/Literals.swift b/lib/ASTGen/Sources/ASTGen/Literals.swift
index 2b4a3edc5e48b..7f2a1c2e481a9 100644
--- a/lib/ASTGen/Sources/ASTGen/Literals.swift
+++ b/lib/ASTGen/Sources/ASTGen/Literals.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -55,14 +55,14 @@ extension ASTGenVisitor {
     let stringLiteralKind = node.stringLiteralKind ?? .singleLine
     let delimiterLength = node.delimiterLength
     let startLoc = self.generateSourceLoc(node)
-    let afterQuoteLoc: BridgedSourceLoc = {
+    let afterQuoteLoc: SourceLoc = {
       var l = startLoc
       if let pound = node.openingPounds {
-        l = l.advanced(by: pound.trimmedLength.utf8Length)
-        l = l.advanced(by: pound.trailingTriviaLength.utf8Length)
-        l = l.advanced(by: node.openingQuote.leadingTriviaLength.utf8Length)
+        l = l.advanced(by: CInt(pound.trimmedLength.utf8Length))
+        l = l.advanced(by: CInt(pound.trailingTriviaLength.utf8Length))
+        l = l.advanced(by: CInt(node.openingQuote.leadingTriviaLength.utf8Length))
       }
-      l = l.advanced(by: node.openingQuote.trimmedLength.utf8Length)
+      l = l.advanced(by: CInt(node.openingQuote.trimmedLength.utf8Length))
       return l
     }()
 
@@ -76,12 +76,12 @@ extension ASTGenVisitor {
     // Name reference to `appendLiteral(_:)`
     let appendLiteral = BridgedDeclNameRef.createParsed(
       self.ctx,
-      baseName: .createIdentifier(self.ctx.getIdentifier("appendLiteral")),
-      argumentLabels: CollectionOfOne(BridgedIdentifier()).bridgedArray(in: self)
+      baseName: .init(self.ctx.getIdentifier("appendLiteral")),
+      argumentLabels: CollectionOfOne(Identifier()).bridgedArray(in: self)
     )
     // Name reference to `appendInterpolation`. Arguments labels are not determined yet.
     let appendInterpolation = BridgedDeclNameRef.createParsed(
-      .createIdentifier(self.ctx.getIdentifier("appendInterpolation"))
+      .init(self.ctx.getIdentifier("appendInterpolation"))
     )
 
     // Total byte length of "literal" segments.
@@ -91,7 +91,7 @@ extension ASTGenVisitor {
 
     // In multi-line string literals, each line has '.stringSegment' even without
     // interpolations. We need to join them into single string literal value in AST.
-    var currLiteral: (value: String, loc: BridgedSourceLoc)? = nil
+    var currLiteral: (value: String, loc: SourceLoc)? = nil
     var isFirst = true
     func consumeCurrentLiteralValue() {
       guard var literal = currLiteral else {
diff --git a/lib/ASTGen/Sources/ASTGen/ParameterClause.swift b/lib/ASTGen/Sources/ASTGen/ParameterClause.swift
index 9edb5c250adcd..69280d2d2aa34 100644
--- a/lib/ASTGen/Sources/ASTGen/ParameterClause.swift
+++ b/lib/ASTGen/Sources/ASTGen/ParameterClause.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2023-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -120,12 +120,12 @@ extension ASTGenVisitor {
     }
 
     // FIXME: This location should be derived from the type repr.
-    let specifierLoc: BridgedSourceLoc = nil
+    let specifierLoc: SourceLoc = nil
 
-    let paramName: BridgedIdentifier
-    let paramNameLoc: BridgedSourceLoc
-    let argName: BridgedIdentifier
-    let argNameLoc: BridgedSourceLoc
+    let paramName: Identifier
+    let paramNameLoc: SourceLoc
+    let argName: Identifier
+    let argNameLoc: SourceLoc
 
     // Map the first name and second name to argument name and parameter name.
     // If we have both, use them. If we only have one, then use that as the
diff --git a/lib/ASTGen/Sources/ASTGen/Regex.swift b/lib/ASTGen/Sources/ASTGen/Regex.swift
index 6461abbcb97c0..645bedc0ceb3d 100644
--- a/lib/ASTGen/Sources/ASTGen/Regex.swift
+++ b/lib/ASTGen/Sources/ASTGen/Regex.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -67,7 +67,7 @@ public func _RegexLiteralLexingFn(
       var message = error.message
       message.withBridgedString { message in
         BridgedDiagnostic(
-          at: BridgedSourceLoc(raw: error.location),
+          at: SourceLoc(raw: error.location),
           message: message,
           severity: .error,
           engine: BridgedDiagnosticEngine(raw: diagEnginePtr)
@@ -99,7 +99,7 @@ public func _RegexLiteralParsingFn(
   _ captureStructureOut: UnsafeMutableRawPointer,
   _ captureStructureSize: UInt,
   _ patternFeaturesOut: UnsafeMutablePointer<BridgedRegexLiteralPatternFeatures>,
-  _ bridgedDiagnosticBaseLoc: BridgedSourceLoc,
+  _ baseLoc: SourceLoc,
   _ bridgedDiagnosticEngine: BridgedDiagnosticEngine
 ) -> Bool {
   let str = String(bridged: input)
@@ -119,10 +119,10 @@ public func _RegexLiteralParsingFn(
     versionOut.pointee = UInt(version)
     return false
   } catch let error as CompilerParseError {
-    var diagLoc = bridgedDiagnosticBaseLoc
+    var diagLoc = baseLoc
     if diagLoc.isValid, let errorLoc = error.location {
       let offset = str.utf8.distance(from: str.startIndex, to: errorLoc)
-      diagLoc = diagLoc.advanced(by: offset)
+      diagLoc = diagLoc.advanced(by: CInt(offset))
     }
     var message = error.message
     message.withBridgedString { message in
diff --git a/lib/ASTGen/Sources/ASTGen/SourceFile.swift b/lib/ASTGen/Sources/ASTGen/SourceFile.swift
index d7692a4641607..b6823c5a5f944 100644
--- a/lib/ASTGen/Sources/ASTGen/SourceFile.swift
+++ b/lib/ASTGen/Sources/ASTGen/SourceFile.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -43,18 +43,26 @@ public struct ExportedSourceFile {
   /// This is a cached value; access via configuredRegions(astContext:).
   var _configuredRegions: ConfiguredRegions? = nil
 
-  public func position(of location: BridgedSourceLoc) -> AbsolutePosition? {
+  /// Configured regions for this source file assuming if it were being treated
+  /// as Embedded Swift. This is used only when we are compiling non-Embedded
+  /// Swift but diagnosing uses of constructs that aren't allowed in Embedded
+  /// Swift.
+  ///
+  /// This is a cached value; access via configuredRegionsAsEmbedded(astContext:).
+  var _configuredRegionsIfEmbedded: ConfiguredRegions? = nil
+
+  public func position(of location: SourceLoc) -> AbsolutePosition? {
     let sourceFileBaseAddress = UnsafeRawPointer(buffer.baseAddress!)
-    guard let opaqueValue = location.getOpaquePointerValue() else {
+    guard let rawAddress = location.raw else {
       return nil
     }
-    return AbsolutePosition(utf8Offset: opaqueValue - sourceFileBaseAddress)
+    return AbsolutePosition(utf8Offset: rawAddress - sourceFileBaseAddress)
   }
 
-  /// Retrieve a bridged source location for the given absolute position in
+  /// Retrieve a C++ source location for the given absolute position in
   /// this source file.
-  public func sourceLoc(at position: AbsolutePosition) -> BridgedSourceLoc {
-    BridgedSourceLoc(at: position, in: buffer)
+  public func sourceLoc(at position: AbsolutePosition) -> SourceLoc {
+    SourceLoc(at: position, in: buffer)
   }
 }
 
@@ -64,7 +72,7 @@ extension Parser.ExperimentalFeatures {
     guard let context = context else { return }
 
     func mapFeature(_ bridged: BridgedFeature, to feature: Self) {
-      if context.langOptsHasFeature(bridged) {
+      if context.langOpts.hasFeature(bridged) {
         insert(feature)
       }
     }
@@ -75,10 +83,10 @@ extension Parser.ExperimentalFeatures {
     mapFeature(.NonescapableTypes, to: .nonescapableTypes)
     mapFeature(.TrailingComma, to: .trailingComma)
     mapFeature(.CoroutineAccessors, to: .coroutineAccessors)
-    mapFeature(.ABIAttribute, to: .abiAttribute)
     mapFeature(.OldOwnershipOperatorSpellings, to: .oldOwnershipOperatorSpellings)
     mapFeature(.KeyPathWithMethodMembers, to: .keypathWithMethodMembers)
-    mapFeature(.InlineArrayTypeSugar, to: .inlineArrayTypeSugar)
+    mapFeature(.DefaultIsolationPerFile, to: .defaultIsolationPerFile)
+    mapFeature(.BorrowAndMutateAccessors, to: .borrowAndMutateAccessors)
   }
 }
 
diff --git a/lib/ASTGen/Sources/ASTGen/Stmts.swift b/lib/ASTGen/Sources/ASTGen/Stmts.swift
index ca9b4e939dfcf..c97d8d558e3c4 100644
--- a/lib/ASTGen/Sources/ASTGen/Stmts.swift
+++ b/lib/ASTGen/Sources/ASTGen/Stmts.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -221,7 +221,7 @@ extension ASTGenVisitor {
         let identifier = pat.boundName
         if identifier != nil {
           // For `if let foo { }` Create a `foo` expression as the initializer.
-          let ref = BridgedDeclNameRef.createParsed(.createIdentifier(identifier))
+          let ref = BridgedDeclNameRef.createParsed(.init(identifier))
           let loc = BridgedDeclNameLoc.createParsed(self.generateSourceLoc(node.pattern))
           initializer =
             BridgedUnresolvedDeclRefExpr.createParsed(
@@ -511,8 +511,8 @@ extension ASTGenVisitor {
 
   func generate(switchCase node: SwitchCaseSyntax) -> BridgedCaseStmt {
     let unknownAttrLoc = self.generateSourceLoc(node.attribute?.atSign)
-    let introducerLoc: BridgedSourceLoc
-    let terminatorLoc: BridgedSourceLoc
+    let introducerLoc: SourceLoc
+    let terminatorLoc: SourceLoc
     let items: BridgedArrayRef
     switch node.label {
     case .case(let node):
@@ -600,8 +600,8 @@ extension ASTGenVisitor {
   func generate(yieldStmt node: YieldStmtSyntax) -> BridgedYieldStmt {
     // FIXME: SwiftParser always parses `yield(...)` as an expression.
     // ASTGen needs to convert the call to an expression (in generate(codeBlockItem:)?)
-    let lParenLoc: BridgedSourceLoc
-    let rParenLoc: BridgedSourceLoc
+    let lParenLoc: SourceLoc
+    let rParenLoc: SourceLoc
     let yields: BridgedArrayRef
     switch node.yieldedExpressions {
     case .multiple(let node):
diff --git a/lib/ASTGen/Sources/ASTGen/TypeAttrs.swift b/lib/ASTGen/Sources/ASTGen/TypeAttrs.swift
index 0aea4fe145ca4..61276068d515d 100644
--- a/lib/ASTGen/Sources/ASTGen/TypeAttrs.swift
+++ b/lib/ASTGen/Sources/ASTGen/TypeAttrs.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -36,92 +36,99 @@ extension ASTGenVisitor {
   func generateTypeAttribute(attribute node: AttributeSyntax) -> BridgedTypeOrCustomAttr? {
     if let identTy = node.attributeName.as(IdentifierTypeSyntax.self) {
       let attrName = identTy.name.rawText
-      let attrKind = BridgedTypeAttrKind(from: attrName.bridged)
+      let attrKind: swift.TypeAttrKind?
+      do {
+        let bridgedOptional = BridgedOptionalTypeAttrKind(from: attrName.bridged)
+        attrKind = if bridgedOptional.hasValue {
+          bridgedOptional.value
+        } else {
+          nil
+        }
+      }
 
       switch attrKind {
       // Simple type attributes.
-      case .autoclosure,
-        .addressable,
-        .escaping,
-        .noEscape,
-        .noDerivative,
-        .async,
-        .sendable,
-        .retroactive,
-        .unchecked,
-        .unsafe,
-        .preconcurrency,
-        .local,
-        .noMetadata,
-        .nonisolated,
-        .packGuaranteed,
-        .packInout,
-        .packOut,
-        .packOwned,
-        .pseudogeneric,
-        .yields,
-        .yieldMany,
-        .yieldOnce,
-        .yieldOnce2,
-        .thin,
-        .thick,
-        .unimplementable:
-        return self.generateSimpleTypeAttr(attribute: node, kind: attrKind)
+      case .Autoclosure,
+        .Addressable,
+        .Concurrent,
+        .Escaping,
+        .NoEscape,
+        .NoDerivative,
+        .Async,
+        .Sendable,
+        .Retroactive,
+        .Unchecked,
+        .Unsafe,
+        .Preconcurrency,
+        .Local,
+        .NoMetadata,
+        .Nonisolated,
+        .PackGuaranteed,
+        .PackInout,
+        .PackOut,
+        .PackOwned,
+        .Pseudogeneric,
+        .Yields,
+        .YieldMany,
+        .YieldOnce,
+        .YieldOnce2,
+        .Thin,
+        .Thick,
+        .Unimplementable:
+        return self.generateSimpleTypeAttr(attribute: node, kind: attrKind!)
           .map(BridgedTypeOrCustomAttr.typeAttr(_:))
 
-      case .convention:
+      case .Convention:
         return (self.generateConventionTypeAttr(attribute: node)?.asTypeAttribute)
           .map(BridgedTypeOrCustomAttr.typeAttr(_:))
-      case .differentiable:
+      case .Differentiable:
         return (self.generateDifferentiableTypeAttr(attribute: node)?.asTypeAttribute)
           .map(BridgedTypeOrCustomAttr.typeAttr(_:))
-      case .execution:
-        return (self.generateExecutionTypeAttr(attribute: node)?.asTypeAttribute)
-          .map(BridgedTypeOrCustomAttr.typeAttr(_:))
-      case .opaqueReturnTypeOf:
+      case .OpaqueReturnTypeOf:
         return (self.generateOpaqueReturnTypeOfTypeAttr(attribute: node)?.asTypeAttribute)
           .map(BridgedTypeOrCustomAttr.typeAttr(_:))
-      case .isolated:
+      case .Isolated:
         return (self.generateIsolatedTypeAttr(attribute: node)?.asTypeAttribute)
           .map(BridgedTypeOrCustomAttr.typeAttr(_:))
 
       // SIL type attributes are not supported.
-      case .autoreleased,
-        .blockStorage,
-        .box,
-        .calleeGuaranteed,
-        .calleeOwned,
-        .capturesGenerics,
-        .direct,
-        .dynamicSelf,
-        .error,
-        .errorIndirect,
-        .errorUnowned,
-        .guaranteed,
-        .in,
-        .inConstant,
-        .inGuaranteed,
-        .inCXX,
-        .inout,
-        .inoutAliasable,
-        .moveOnly,
-        .objCMetatype,
-        .opened,
-        .out,
-        .owned,
-        .packElement,
-        .silIsolated,
-        .silUnmanaged,
-        .silUnowned,
-        .silWeak,
-        .silSending,
-        .silImplicitLeadingParam,
-        .unownedInnerPointer:
+      case .Autoreleased,
+        .BlockStorage,
+        .Box,
+        .CalleeGuaranteed,
+        .CalleeOwned,
+        .CapturesGenerics,
+        .Direct,
+        .DynamicSelf,
+        .Error,
+        .ErrorIndirect,
+        .ErrorUnowned,
+        .Guaranteed,
+        .GuaranteedAddress,
+        .In,
+        .InConstant,
+        .InGuaranteed,
+        .InCXX,
+        .Inout,
+        .InoutAliasable,
+        .MoveOnly,
+        .ObjCMetatype,
+        .Opened,
+        .Out,
+        .Owned,
+        .PackElement,
+        .SILIsolated,
+        .SILUnmanaged,
+        .SILUnowned,
+        .SILWeak,
+        .SILSending,
+        .SILImplicitLeadingParam,
+        .UnownedInnerPointer:
         // TODO: Diagnose or fallback to CustomAttr?
         fatalError("SIL type attributes are not supported")
         break;
 
-      case .none:
+      case nil:
         // Not a builtin type attribute. Fall back to CustomAttr
         break;
       }
@@ -133,7 +140,7 @@ extension ASTGenVisitor {
     return nil
   }
 
-  func generateSimpleTypeAttr(attribute node: AttributeSyntax, kind: BridgedTypeAttrKind) -> BridgedTypeAttribute? {
+  func generateSimpleTypeAttr(attribute node: AttributeSyntax, kind: swift.TypeAttrKind) -> BridgedTypeAttribute? {
     // TODO: Diagnose extraneous arguments.
     return BridgedTypeAttribute.createSimple(
       self.ctx,
@@ -157,16 +164,16 @@ extension ASTGenVisitor {
         return nil
       }
 
-      let cTypeNameLoc: BridgedSourceLoc?
+      let typeNameLoc: SourceLoc
       let cTypeName: BridgedStringRef?
       if !args.isEmpty {
-        cTypeNameLoc = self.generateSourceLoc(args.first?.expression)
+        typeNameLoc = self.generateSourceLoc(args.first?.expression)
         cTypeName = self.generateConsumingSimpleStringLiteralAttrOption(args: &args, label: "cType")
         guard cTypeName != nil else {
           return nil
         }
       } else {
-        cTypeNameLoc = nil
+        typeNameLoc = nil
         cTypeName = nil
       }
 
@@ -182,14 +189,14 @@ extension ASTGenVisitor {
         nameLoc: nameAndLoc.loc,
         witnessMethodProtocol: witnessMethodProtocol,
         clangType: cTypeName ?? BridgedStringRef(),
-        clangTypeLoc: cTypeNameLoc ?? BridgedSourceLoc()
+        clangTypeLoc: typeNameLoc
       )
     }
   }
 
   func generateDifferentiableTypeAttr(attribute node: AttributeSyntax) -> BridgedDifferentiableTypeAttr? {
     let differentiability: BridgedDifferentiabilityKind
-    let differentiabilityLoc: BridgedSourceLoc
+    let differentiabilityLoc: SourceLoc
     if let args = node.arguments {
       guard let args = args.as(DifferentiableAttributeArgumentsSyntax.self) else {
         fatalError("(compiler bug) invalid arguments for @differentiable attribute")
@@ -239,34 +246,6 @@ extension ASTGenVisitor {
       kindLoc: differentiabilityLoc
     )
   }
-
-  func generateExecutionTypeAttr(attribute node: AttributeSyntax) -> BridgedExecutionTypeAttr? {
-    let behaviorLoc = self.generateSourceLoc(node.arguments)
-    let behavior: BridgedExecutionTypeAttrExecutionKind? = self.generateSingleAttrOption(
-      attribute: node,
-      {
-        switch $0.rawText {
-        case "concurrent": return .concurrent
-        case "caller": return .caller
-        default:
-          // TODO: Diagnose.
-          return nil
-        }
-      }
-    )
-    guard let behavior else {
-      return nil
-    }
-      
-    return .createParsed(
-      self.ctx,
-      atLoc: self.generateSourceLoc(node.atSign),
-      nameLoc: self.generateSourceLoc(node.attributeName),
-      parensRange: self.generateAttrParensRange(attribute: node),
-      behavior: behavior,
-      behaviorLoc: behaviorLoc
-    )
-  }
   
   func generateIsolatedTypeAttr(attribute node: AttributeSyntax) -> BridgedIsolatedTypeAttr? {
     let isolationKindLoc = self.generateSourceLoc(node.arguments)
@@ -334,9 +313,9 @@ extension ASTGenVisitor {
 
   }
   
-  func generateAttrParensRange(attribute node: AttributeSyntax) -> BridgedSourceRange {
+  func generateAttrParensRange(attribute node: AttributeSyntax) -> SourceRange {
     guard let lParen = node.leftParen else {
-      return BridgedSourceRange()
+      return .init()
     }
     return self.generateSourceRange(start: lParen, end: node.lastToken(viewMode: .sourceAccurate)!)
   }
diff --git a/lib/ASTGen/Sources/ASTGen/Types.swift b/lib/ASTGen/Sources/ASTGen/Types.swift
index a0cd884131f0b..600b48244b735 100644
--- a/lib/ASTGen/Sources/ASTGen/Types.swift
+++ b/lib/ASTGen/Sources/ASTGen/Types.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -109,7 +109,7 @@ extension ASTGenVisitor {
       self.ctx,
       count: self.generate(genericArgument: node.count.argument),
       element: self.generate(genericArgument: node.element.argument),
-      brackets: BridgedSourceRange(
+      brackets: .init(
         start: self.generateSourceLoc(node.leftSquare),
         end: self.generateSourceLoc(node.rightSquare)
       )
@@ -120,7 +120,7 @@ extension ASTGenVisitor {
     let (name, nameLoc) = self.generateIdentifierAndSourceLoc(node.name)
 
     let genericArguments: BridgedArrayRef
-    let angleRange: BridgedSourceRange
+    let angleRange: SourceRange
     if let generics = node.genericArgumentClause {
       genericArguments = generics.arguments.lazy.map {
         self.generate(genericArgument: $0.argument)
@@ -193,7 +193,7 @@ extension ASTGenVisitor {
     let loc = self.generateSourceLoc(node.previousToken(viewMode: .sourceAccurate))
     return BridgedErrorTypeRepr.create(
       self.ctx,
-      range: BridgedSourceRange(start: loc, end: loc)
+      range: .init(start: loc)
     ).asTypeRepr
   }
 
@@ -357,11 +357,12 @@ extension ASTGenVisitor {
 
     // Specifiers
     var ownership: BridgedParamSpecifier = .default
-    var ownershipLoc: BridgedSourceLoc = nil
-    var isolatedLoc: BridgedSourceLoc = nil
-    var constLoc: BridgedSourceLoc = nil
-    var sendingLoc: BridgedSourceLoc = nil
+    var ownershipLoc: SourceLoc = nil
+    var isolatedLoc: SourceLoc = nil
+    var constLoc: SourceLoc = nil
+    var sendingLoc: SourceLoc = nil
     var lifetimeEntry: BridgedLifetimeEntry? = nil
+    var nonisolatedLoc: SourceLoc = nil
 
     // TODO: Diagnostics for duplicated specifiers, and ordering.
     for node in node.specifiers {
@@ -398,6 +399,8 @@ extension ASTGenVisitor {
           ),
           sources: node.arguments.lazy.compactMap(self.generateLifetimeDescriptor(lifetimeSpecifierArgument:)).bridgedArray(in: self)
         )
+      case .nonisolatedTypeSpecifier(_):
+        nonisolatedLoc = loc
       }
     }
 
@@ -454,6 +457,14 @@ extension ASTGenVisitor {
       ).asTypeRepr
     }
 
+    if nonisolatedLoc.isValid {
+      type = BridgedCallerIsolatedTypeRepr.createParsed(
+        self.ctx,
+        base: type,
+        specifierLoc: nonisolatedLoc
+      ).asTypeRepr
+    }
+
     return type
   }
 }
@@ -491,7 +502,7 @@ extension ASTGenVisitor {
 extension ASTGenVisitor {
   struct GeneratedGenericArguments {
     var arguments: BridgedArrayRef = .init()
-    var range: BridgedSourceRange = .init()
+    var range: SourceRange = .init()
   }
 
   /// Generate 'TypeRepr' from a expression, because 'conformances' arguments in
diff --git a/lib/ASTGen/Sources/BasicSwift/CMakeLists.txt b/lib/ASTGen/Sources/BasicSwift/CMakeLists.txt
new file mode 100644
index 0000000000000..beeb67ef70cc2
--- /dev/null
+++ b/lib/ASTGen/Sources/BasicSwift/CMakeLists.txt
@@ -0,0 +1,11 @@
+add_pure_swift_host_library(swiftBasicSwift STATIC CXX_INTEROP
+  StaticBuildConfiguration+LangOptions.swift
+  String+BridgedString.swift
+
+  DEPENDENCIES
+    swiftBasic
+  SWIFT_DEPENDENCIES
+    _CompilerSwiftCompilerPluginMessageHandling
+    _CompilerSwiftSyntax
+    _CompilerSwiftIfConfig
+)
diff --git a/lib/ASTGen/Sources/BasicSwift/StaticBuildConfiguration+LangOptions.swift b/lib/ASTGen/Sources/BasicSwift/StaticBuildConfiguration+LangOptions.swift
new file mode 100644
index 0000000000000..7bdd51e6ae3f3
--- /dev/null
+++ b/lib/ASTGen/Sources/BasicSwift/StaticBuildConfiguration+LangOptions.swift
@@ -0,0 +1,149 @@
+//===--- StaticBuildConfiguration+ASTContext.swift ------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import ASTBridging
+@_spi(PluginMessage) import SwiftCompilerPluginMessageHandling
+import SwiftDiagnostics
+@_spi(Compiler) import SwiftIfConfig
+@_spi(ExperimentalLanguageFeatures) import SwiftParser
+@_spi(ExperimentalLanguageFeatures) import SwiftSyntax
+
+extension StaticBuildConfiguration {
+  /// Configuration entries captured in the initializer from a bridged context.
+  private struct ConfigurationEntries {
+    var customConditions: Set<String> = []
+    var features: Set<String> = []
+    var attributes: Set<String> = []
+    var targetOSNames: Set<String> = []
+    var targetArchitectures: Set<String> = []
+    var targetEnvironments: Set<String> = []
+    var targetRuntimes: Set<String> = []
+    var targetPointerAuthenticationSchemes: Set<String> = []
+    var targetObjectFileFormats: Set<String> = []
+  }
+
+  /// Initialize a static build configuration for the given language options.
+  init(langOptions: BridgedLangOptions) {
+    var entries = ConfigurationEntries()
+
+    langOptions.enumerateBuildConfigurationEntries(callbackContext: &entries) { cContext, entries, key, value in
+      let entries = entries.assumingMemoryBound(to: ConfigurationEntries.self)
+      switch key {
+      case .BCKAttribute:
+        entries.pointee.attributes.insert(String(bridged: value))
+      case .BCKCustomCondition:
+        entries.pointee.customConditions.insert(String(bridged: value))
+      case .BCKFeature:
+        entries.pointee.features.insert(String(bridged: value))
+      case .BCKTargetOSName:
+        entries.pointee.targetOSNames.insert(String(bridged: value))
+      case .BCKTargetArchitecture:
+        entries.pointee.targetArchitectures.insert(String(bridged: value))
+      case .BCKTargetEnvironment:
+        entries.pointee.targetEnvironments.insert(String(bridged: value))
+      case .BCKTargetRuntime:
+        entries.pointee.targetRuntimes.insert(String(bridged: value))
+      case .BCKTargetPointerAuthenticationScheme:
+        entries.pointee.targetPointerAuthenticationSchemes.insert(String(bridged: value))
+      case .BCKTargetObjectFileFormat:
+        entries.pointee.targetObjectFileFormats.insert(String(bridged: value))
+      }
+    }
+
+    let targetPointerBitWidth = Int(langOptions.targetPointerBitWidth)
+
+    // Atomic bit widths.
+    let targetAtomicBitWidths: [Int]
+    do {
+      var bitWidthsBuf: UnsafeMutablePointer<SwiftInt>? = nil
+      let bitWidthsCount = langOptions.getTargetAtomicBitWidths(&bitWidthsBuf)
+      targetAtomicBitWidths = Array(UnsafeMutableBufferPointer(start: bitWidthsBuf, count: bitWidthsCount))
+      deallocateIntBuffer(bitWidthsBuf);
+    }
+
+    let endianness: Endianness
+    switch langOptions.targetEndianness {
+    case .EndianBig: endianness = .big
+    case .EndianLittle: endianness = .little
+    }
+
+    let languageVersion = getVersionTuple { langOptions.getLanguageVersion(&$0) }
+    let compilerVersion = getVersionTuple { langOptions.getCompilerVersion(&$0) }
+    self.init(
+      customConditions: entries.customConditions,
+      features: entries.features,
+      attributes: entries.attributes,
+      targetOSs: entries.targetOSNames,
+      targetArchitectures: entries.targetArchitectures,
+      targetEnvironments: entries.targetEnvironments,
+      targetRuntimes: entries.targetRuntimes,
+      targetPointerAuthenticationSchemes: entries.targetPointerAuthenticationSchemes,
+      targetObjectFileFormats: entries.targetObjectFileFormats,
+      targetPointerBitWidth: targetPointerBitWidth,
+      targetAtomicBitWidths: targetAtomicBitWidths,
+      endianness: endianness,
+      languageVersion: languageVersion,
+      compilerVersion: compilerVersion
+    )
+  }
+}
+
+/// Get a version tuple from C++.
+private func getVersionTuple(
+  body: (inout UnsafeMutablePointer<SwiftInt>?) -> Int
+) -> VersionTuple {
+  var componentsBuf: UnsafeMutablePointer<SwiftInt>? = nil
+  let count = body(&componentsBuf)
+  let version = VersionTuple(
+    components: Array(UnsafeMutableBufferPointer(start: componentsBuf, count: count))
+  )
+  deallocateIntBuffer(componentsBuf);
+  return version
+}
+
+@_cdecl("swift_ASTGen_printStaticBuildConfiguration")
+public func printStaticBuildConfiguration(
+  langOptions: BridgedLangOptions
+) -> BridgedStringRef {
+  let config = StaticBuildConfiguration(langOptions: langOptions)
+  let result = try? JSON.encode(config).withUnsafeBufferPointer { buffer in
+    let ptr = UnsafeMutablePointer<UInt8>.allocate(
+      capacity: buffer.count + 1
+    )
+    if let baseAddress = buffer.baseAddress {
+      ptr.initialize(from: baseAddress, count: buffer.count)
+    }
+
+    // null terminate, for client's convenience.
+    ptr[buffer.count] = 0
+
+    return BridgedStringRef(data: ptr, count: buffer.count)
+  }
+
+  return result ?? BridgedStringRef()
+}
+
+@_cdecl("swift_Basic_createStaticBuildConfiguration")
+public func createStaticBuildConfiguration(
+  cLangOpts: BridgedLangOptions
+) -> UnsafeMutableRawPointer {
+  let storage = UnsafeMutablePointer<StaticBuildConfiguration>.allocate(capacity: 1)
+  storage.initialize(to: StaticBuildConfiguration(langOptions: cLangOpts))
+  return UnsafeMutableRawPointer(storage)
+}
+
+/// Free the given static build configuration.
+@_cdecl("swift_Basic_freeStaticBuildConfiguration")
+public func freeStaticBuildConfiguration(pointer: UnsafeMutableRawPointer) {
+  pointer.assumingMemoryBound(to: StaticBuildConfiguration.self)
+    .deinitialize(count: 1).deallocate()
+}
diff --git a/lib/ASTGen/Sources/BasicSwift/String+BridgedString.swift b/lib/ASTGen/Sources/BasicSwift/String+BridgedString.swift
new file mode 100644
index 0000000000000..ef7fcdb4e6e5b
--- /dev/null
+++ b/lib/ASTGen/Sources/BasicSwift/String+BridgedString.swift
@@ -0,0 +1,28 @@
+//===--- String+BridgedString.swift ---------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import BasicBridging
+
+extension String {
+  public init(bridged: BridgedStringRef) {
+    self.init(
+      decoding: UnsafeBufferPointer(start: bridged.data, count: bridged.count),
+      as: UTF8.self
+    )
+  }
+
+  public mutating func withBridgedString<R>(_ body: (BridgedStringRef) throws -> R) rethrows -> R {
+    try withUTF8 { buffer in
+      try body(BridgedStringRef(data: buffer.baseAddress, count: buffer.count))
+    }
+  }
+}
diff --git a/lib/ASTGen/Sources/CMakeLists.txt b/lib/ASTGen/Sources/CMakeLists.txt
index 57efe7eddacee..1e2f2816f2cbb 100644
--- a/lib/ASTGen/Sources/CMakeLists.txt
+++ b/lib/ASTGen/Sources/CMakeLists.txt
@@ -1,3 +1,4 @@
+add_subdirectory(BasicSwift)
 add_subdirectory(ASTGen)
 add_subdirectory(MacroEvaluation)
 add_subdirectory(SwiftIDEUtilsBridging)
diff --git a/lib/ASTGen/Sources/MacroEvaluation/Macros.swift b/lib/ASTGen/Sources/MacroEvaluation/Macros.swift
index 21c42fbbcbc89..91068283a0d0c 100644
--- a/lib/ASTGen/Sources/MacroEvaluation/Macros.swift
+++ b/lib/ASTGen/Sources/MacroEvaluation/Macros.swift
@@ -14,6 +14,7 @@ import ASTBridging
 import BasicBridging
 @_spi(PluginMessage) @_spi(ExperimentalLanguageFeature) import SwiftCompilerPluginMessageHandling
 import SwiftDiagnostics
+import SwiftIfConfig
 import SwiftParser
 import SwiftSyntax
 @_spi(ExperimentalLanguageFeature) @_spi(Compiler) import SwiftSyntaxMacroExpansion
@@ -244,9 +245,6 @@ func checkMacroDefinition(
         case "IsolationMacro":
           return Int(BridgedMacroDefinitionKind.builtinIsolationMacro.rawValue)
 
-        case "SwiftSettingsMacro":
-          return Int(BridgedMacroDefinitionKind.builtinSwiftSettingsMacro.rawValue)
-
         // These builtins don't exist, but are put into the standard library at
         // least for documentation purposes right now. Don't emit a warning for
         // them, but do fail operation.
@@ -422,7 +420,7 @@ func makeExpansionOutputResult(
 @_cdecl("swift_Macros_expandFreestandingMacro")
 @usableFromInline
 func expandFreestandingMacro(
-  diagEnginePtr: UnsafeMutableRawPointer,
+  cContext: BridgedASTContext,
   macroPtr: UnsafeRawPointer,
   discriminatorText: UnsafePointer<CChar>,
   rawMacroRole: UInt8,
@@ -464,7 +462,7 @@ func expandFreestandingMacro(
   let expandedSource: String? = expandFreestandingMacroImpl(
     macroPtr: macroPtr,
     macroRole: macroRole,
-    diagEnginePtr: diagEnginePtr,
+    cContext: cContext,
     expansionSyntax: expansion,
     sourceFilePtr: sourceFilePtr,
     discriminator: discriminator
@@ -479,7 +477,7 @@ func expandFreestandingMacro(
 func expandFreestandingMacroImpl(
   macroPtr: UnsafeRawPointer,
   macroRole: MacroRole,
-  diagEnginePtr: UnsafeMutableRawPointer,
+  cContext: BridgedASTContext,
   expansionSyntax: FreestandingMacroExpansionSyntax,
   sourceFilePtr: UnsafePointer<ExportedSourceFile>,
   discriminator: String
@@ -508,14 +506,15 @@ func expandFreestandingMacroImpl(
   }
 
   // Send the message.
-  let message = HostToPluginMessage.expandFreestandingMacro(
-    macro: .init(moduleName: macro.moduleName, typeName: macro.typeName, name: macroName),
-    macroRole: pluginMacroRole,
-    discriminator: discriminator,
-    syntax: PluginMessage.Syntax(syntax: Syntax(expansionSyntax), in: sourceFilePtr)!,
-    lexicalContext: pluginLexicalContext(of: expansionSyntax)
-  )
   do {
+    let message = HostToPluginMessage.expandFreestandingMacro(
+      macro: .init(moduleName: macro.moduleName, typeName: macro.typeName, name: macroName),
+      macroRole: pluginMacroRole,
+      discriminator: discriminator,
+      syntax: PluginMessage.Syntax(syntax: Syntax(expansionSyntax), in: sourceFilePtr)!,
+      lexicalContext: pluginLexicalContext(of: expansionSyntax),
+      staticBuildConfiguration: try cContext.staticBuildConfiguration.asJSON
+    )
     let result = try macro.plugin.sendMessageAndWait(message)
     let expandedSource: String?
     let diagnostics: [PluginMessage.Diagnostic]
@@ -530,14 +529,14 @@ func expandFreestandingMacroImpl(
 
     // Process the result.
     if !diagnostics.isEmpty {
-      let diagEngine = PluginDiagnosticsEngine(cxxDiagnosticEngine: diagEnginePtr)
+      let diagEngine = PluginDiagnosticsEngine(cContext: cContext)
       diagEngine.add(exportedSourceFile: sourceFilePtr)
       diagEngine.emit(diagnostics, messageSuffix: " (from macro '\(macroName)')")
     }
     return expandedSource
 
   } catch let error {
-    let srcMgr = SourceManager(cxxDiagnosticEngine: diagEnginePtr)
+    let srcMgr = SourceManager(cContext: cContext)
     srcMgr.insert(sourceFilePtr)
     srcMgr.diagnose(
       diagnostic: .init(
@@ -555,7 +554,7 @@ func expandFreestandingMacroImpl(
 @_cdecl("swift_Macros_expandAttachedMacro")
 @usableFromInline
 func expandAttachedMacro(
-  diagEnginePtr: UnsafeMutableRawPointer,
+  cContext: BridgedASTContext,
   macroPtr: UnsafeRawPointer,
   discriminatorText: UnsafePointer<CChar>,
   qualifiedTypeText: UnsafePointer<CChar>,
@@ -613,7 +612,7 @@ func expandAttachedMacro(
   let conformanceList = String(cString: conformanceListText)
 
   let expandedSource: String? = expandAttachedMacroImpl(
-    diagEnginePtr: diagEnginePtr,
+    cContext: cContext,
     macroPtr: macroPtr,
     rawMacroRole: rawMacroRole,
     discriminator: discriminator,
@@ -648,7 +647,7 @@ private func pluginLexicalContext(of node: some SyntaxProtocol) -> [PluginMessag
 }
 
 func expandAttachedMacroImpl(
-  diagEnginePtr: UnsafeMutableRawPointer,
+  cContext: BridgedASTContext,
   macroPtr: UnsafeRawPointer,
   rawMacroRole: UInt8,
   discriminator: String,
@@ -721,18 +720,19 @@ func expandAttachedMacroImpl(
 
 
   // Send the message.
-  let message = HostToPluginMessage.expandAttachedMacro(
-    macro: .init(moduleName: macro.moduleName, typeName: macro.typeName, name: macroName),
-    macroRole: macroRole,
-    discriminator: discriminator,
-    attributeSyntax: customAttributeSyntax,
-    declSyntax: declSyntax,
-    parentDeclSyntax: parentDeclSyntax,
-    extendedTypeSyntax: extendedTypeSyntax,
-    conformanceListSyntax: conformanceListSyntax,
-    lexicalContext: pluginLexicalContext(of: declarationNode)
-  )
   do {
+    let message = HostToPluginMessage.expandAttachedMacro(
+      macro: .init(moduleName: macro.moduleName, typeName: macro.typeName, name: macroName),
+      macroRole: macroRole,
+      discriminator: discriminator,
+      attributeSyntax: customAttributeSyntax,
+      declSyntax: declSyntax,
+      parentDeclSyntax: parentDeclSyntax,
+      extendedTypeSyntax: extendedTypeSyntax,
+      conformanceListSyntax: conformanceListSyntax,
+      lexicalContext: pluginLexicalContext(of: declarationNode),
+      staticBuildConfiguration: try cContext.staticBuildConfiguration.asJSON
+    )
     let expandedSource: String?
     let diagnostics: [PluginMessage.Diagnostic]
     switch try macro.plugin.sendMessageAndWait(message) {
@@ -759,7 +759,7 @@ func expandAttachedMacroImpl(
 
     // Process the result.
     if !diagnostics.isEmpty {
-      let diagEngine = PluginDiagnosticsEngine(cxxDiagnosticEngine: diagEnginePtr)
+      let diagEngine = PluginDiagnosticsEngine(cContext: cContext)
       diagEngine.add(exportedSourceFile: customAttrSourceFilePtr)
       diagEngine.add(exportedSourceFile: declarationSourceFilePtr)
       if let parentDeclSourceFilePtr = parentDeclSourceFilePtr {
@@ -770,7 +770,7 @@ func expandAttachedMacroImpl(
     return expandedSource
 
   } catch let error {
-    let srcMgr = SourceManager(cxxDiagnosticEngine: diagEnginePtr)
+    let srcMgr = SourceManager(cContext: cContext)
     srcMgr.insert(customAttrSourceFilePtr)
     srcMgr.insert(declarationSourceFilePtr)
     if let parentDeclSourceFilePtr = parentDeclSourceFilePtr {
@@ -790,3 +790,11 @@ func expandAttachedMacroImpl(
   }
 }
 
+extension StaticBuildConfiguration {
+  /// Form the JSON representation of this static build configuration.
+  var asJSON: String {
+    get throws {
+      try String(decoding: JSON.encode(self), as: UTF8.self)
+    }
+  }
+}
diff --git a/lib/ASTGen/Sources/MacroEvaluation/PluginHost.swift b/lib/ASTGen/Sources/MacroEvaluation/PluginHost.swift
index 5e134f64fea68..85005e2f64fa9 100644
--- a/lib/ASTGen/Sources/MacroEvaluation/PluginHost.swift
+++ b/lib/ASTGen/Sources/MacroEvaluation/PluginHost.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift open source project
 //
-// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2023-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See http://swift.org/LICENSE.txt for license information
@@ -201,8 +201,8 @@ class PluginDiagnosticsEngine {
   private let bridgedDiagEngine: BridgedDiagnosticEngine
   private var exportedSourceFileByName: [String: UnsafePointer<ExportedSourceFile>] = [:]
 
-  init(cxxDiagnosticEngine: UnsafeMutableRawPointer) {
-    self.bridgedDiagEngine = BridgedDiagnosticEngine(raw: cxxDiagnosticEngine)
+  init(cContext: BridgedASTContext) {
+    self.bridgedDiagEngine = cContext.diags
   }
 
   /// Failable convenience initializer for optional cxx engine pointer.
@@ -262,7 +262,7 @@ class PluginDiagnosticsEngine {
     fixItChanges: [PluginMessage.Diagnostic.FixIt.Change] = []
   ) {
     // Map severity
-    let bridgedSeverity: BridgedDiagnosticSeverity
+    let bridgedSeverity: swift.DiagnosticKind
     switch severity {
     case .error: bridgedSeverity = .error
     case .note: bridgedSeverity = .note
@@ -334,7 +334,7 @@ class PluginDiagnosticsEngine {
   private func bridgedSourceLoc(
     at offset: Int,
     in fileName: String
-  ) -> BridgedSourceLoc {
+  ) -> SourceLoc {
     // Find the corresponding exported source file.
     guard let exportedSourceFile = exportedSourceFileByName[fileName] else {
       return nil
@@ -348,20 +348,20 @@ class PluginDiagnosticsEngine {
     guard offset <= exportedSourceFile.pointee.buffer.count else {
       return nil
     }
-    return BridgedSourceLoc(raw: bufferBaseAddress).advanced(by: offset)
+    return SourceLoc(raw: bufferBaseAddress.advanced(by: offset))
   }
 
-  /// C++ source location from a position value from a plugin.
+  /// Returns a C++ source location from a position value from a plugin.
   private func bridgedSourceLoc(
     at position: PluginMessage.Diagnostic.Position
-  ) -> BridgedSourceLoc {
+  ) -> SourceLoc {
     return bridgedSourceLoc(at: position.offset, in: position.fileName)
   }
 
-  /// C++ source range from a range value from a plugin.
+  /// Returns a C++ source range from a range value from a plugin.
   private func bridgedSourceRange(
     for range: PluginMessage.Diagnostic.PositionRange
-  ) -> (start: BridgedSourceLoc, end: BridgedSourceLoc)? {
+  ) -> (start: SourceLoc, end: SourceLoc)? {
     let start = bridgedSourceLoc(at: range.startOffset, in: range.fileName)
     let end = bridgedSourceLoc(at: range.endOffset, in: range.fileName)
 
diff --git a/lib/ASTGen/Sources/MacroEvaluation/SourceManager.swift b/lib/ASTGen/Sources/MacroEvaluation/SourceManager.swift
index 390607f73cd8f..1011d2652419a 100644
--- a/lib/ASTGen/Sources/MacroEvaluation/SourceManager.swift
+++ b/lib/ASTGen/Sources/MacroEvaluation/SourceManager.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -23,6 +23,10 @@ class SourceManager {
     self.bridgedDiagEngine = BridgedDiagnosticEngine(raw: cxxDiagnosticEngine)
   }
 
+  init(cContext: BridgedASTContext) {
+    self.bridgedDiagEngine = cContext.diags
+  }
+
   /// The bridged diagnostic engine (just the wrapped C++ `DiagnosticEngine`).
   let bridgedDiagEngine: BridgedDiagnosticEngine
 
@@ -101,7 +105,7 @@ extension SourceManager {
   func bridgedSourceLoc<Node: SyntaxProtocol>(
     for node: Node,
     at position: AbsolutePosition? = nil
-  ) -> BridgedSourceLoc {
+  ) -> SourceLoc {
     // Find the source file and this node's position within it.
     let (rootNode, rootPosition) = rootSyntax(of: node)
 
@@ -116,7 +120,7 @@ extension SourceManager {
     let nodeOffset = SourceLength(utf8Length: position.utf8Offset - node.position.utf8Offset)
     let realPosition = rootPosition + nodeOffset
 
-    return BridgedSourceLoc(at: realPosition, in: exportedSourceFile.pointee.buffer)
+    return SourceLoc(at: realPosition, in: exportedSourceFile.pointee.buffer)
   }
 }
 
@@ -130,7 +134,7 @@ extension SourceManager {
     fixItChanges: [FixIt.Change] = []
   ) {
     // Map severity
-    let bridgedSeverity = severity.bridged
+    let bridgedSeverity: swift.DiagnosticKind = severity.bridged
 
     // Emit the diagnostic
     var mutableMessage = message
@@ -153,8 +157,8 @@ extension SourceManager {
 
     // Emit changes for a Fix-It.
     for change in fixItChanges {
-      let replaceStartLoc: BridgedSourceLoc
-      let replaceEndLoc: BridgedSourceLoc
+      let replaceStartLoc: SourceLoc
+      let replaceEndLoc: SourceLoc
       var newText: String
 
       switch change {
diff --git a/lib/ASTGen/Sources/SwiftIDEUtilsBridging/NameMatcherBridging.swift b/lib/ASTGen/Sources/SwiftIDEUtilsBridging/NameMatcherBridging.swift
index 8d7e8072a276e..18dd00a8d0eb1 100644
--- a/lib/ASTGen/Sources/SwiftIDEUtilsBridging/NameMatcherBridging.swift
+++ b/lib/ASTGen/Sources/SwiftIDEUtilsBridging/NameMatcherBridging.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -17,10 +17,10 @@ import swiftASTGen
 
 // MARK: - Bridged type initializers
 
-fileprivate extension BridgedCharSourceRange {
+fileprivate extension CharSourceRange {
   init(from range: Range<AbsolutePosition>, in sourceFile: ExportedSourceFile) {
     self.init(
-      start: BridgedSourceLoc(at: range.lowerBound, in: sourceFile.buffer),
+      start: SourceLoc(at: range.lowerBound, in: sourceFile.buffer),
       byteLength: UInt32(range.upperBound.utf8Offset - range.lowerBound.utf8Offset)
     )
   }
@@ -30,7 +30,7 @@ fileprivate extension BridgedCharSourceRangeVector {
   init(from ranges: some Sequence<Range<AbsolutePosition>>, in sourceFile: ExportedSourceFile) {
     self = .init()
     for range in ranges {
-      self.append(BridgedCharSourceRange(from: range, in: sourceFile))
+      self.append(.init(from: range, in: sourceFile))
     }
   }
 }
@@ -75,7 +75,7 @@ extension BridgedResolvedLoc {
     case .selector(let arguments2): arguments = arguments2
     }
     self.init(
-      range: BridgedCharSourceRange(from: resolvedLoc.baseNameRange, in: sourceFile),
+      range: .init(from: resolvedLoc.baseNameRange, in: sourceFile),
       labelRanges: BridgedCharSourceRangeVector(from: arguments.map { $0.range }, in: sourceFile),
       firstTrailingLabel: firstTrailingClosureIndex,
       labelType: LabelRangeType(resolvedLoc.arguments),
@@ -101,7 +101,7 @@ fileprivate extension IDEBridging.ResolvedLocContext {
 @_cdecl("swift_SwiftIDEUtilsBridging_runNameMatcher")
 public func runNameMatcher(
   sourceFilePtr: UnsafeRawPointer,
-  locations: UnsafePointer<BridgedSourceLoc>,
+  locations: UnsafePointer<SourceLoc>,
   locationsCount: UInt
 ) -> UnsafeMutableRawPointer? {
   let sourceFile = sourceFilePtr.bindMemory(to: ExportedSourceFile.self, capacity: 1).pointee
diff --git a/lib/ASTSectionImporter/ASTSectionImporter.cpp b/lib/ASTSectionImporter/ASTSectionImporter.cpp
index b41852496c884..1384630b739f2 100644
--- a/lib/ASTSectionImporter/ASTSectionImporter.cpp
+++ b/lib/ASTSectionImporter/ASTSectionImporter.cpp
@@ -58,7 +58,7 @@ swift::parseASTSection(MemoryBufferSerializedModuleLoader &Loader,
   // headers. Iterate over all AST modules.
   while (!buf.empty()) {
     auto info = serialization::validateSerializedAST(
-        buf, Loader.isRequiredOSSAModules(),
+        buf,
         /*requiredSDK*/StringRef());
 
     assert(info.name.size() < (2 << 10) && "name failed sanity check");
diff --git a/lib/Basic/Assertions.cpp b/lib/Basic/Assertions.cpp
index e195ec0745668..268deebdd73c6 100644
--- a/lib/Basic/Assertions.cpp
+++ b/lib/Basic/Assertions.cpp
@@ -14,7 +14,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/SmallString.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/raw_ostream.h"
 #include "swift/Basic/Assertions.h"
 #include <iostream>
@@ -34,6 +36,27 @@ int CONDITIONAL_ASSERT_Global_enable_flag =
   1; // Default to `on` in debug builds
 #endif
 
+static void ASSERT_help(llvm::raw_ostream &out) {
+  static int ASSERT_help_shown = 0;
+  if (ASSERT_help_shown) {
+    return;
+  }
+  ASSERT_help_shown = 1;
+
+  if (!AssertHelp) {
+    out << "(to display assertion configuration options: -Xllvm -assert-help)\n";
+    return;
+  }
+
+  out << "\n";
+  out << "Control assertion behavior with one or more of the following options:\n\n";
+  out << " -Xllvm -assert-continue\n";
+  out << "     Continue after any failed assertion\n\n";
+}
+
+[[noreturn]]
+static inline void _abortWithMessage(llvm::StringRef message);
+
 void ASSERT_failure(const char *expr, const char *filename, int line, const char *func) {
   // Find the last component of `filename`
   // Needed on Windows MSVC, which lacks __FILE_NAME__
@@ -45,39 +68,24 @@ void ASSERT_failure(const char *expr, const char *filename, int line, const char
     }
   }
 
-  llvm::errs()
-    << "Assertion failed: "
-    << "(" << expr << "), "
-    << "function " << func << " at "
-    << filename << ":"
-    << line << ".\n";
+  llvm::SmallString<0> message;
+  llvm::raw_svector_ostream out(message);
+
+  out << "Assertion failed: "
+      << "(" << expr << "), "
+      << "function " << func << " at "
+      << filename << ":"
+      << line << ".\n";
 
-  ASSERT_help();
+  ASSERT_help(out);
 
   if (AssertContinue) {
+    llvm::errs() << message;
     llvm::errs() << "Continuing after failed assertion (-Xllvm -assert-continue)\n";
     return;
   }
 
-  abort();
-}
-
-void ASSERT_help() {
-  static int ASSERT_help_shown = 0;
-  if (ASSERT_help_shown) {
-    return;
-  }
-  ASSERT_help_shown = 1;
-
-  if (!AssertHelp) {
-    llvm::errs() << "(to display assertion configuration options: -Xllvm -assert-help)\n";
-    return;
-  }
-
-  llvm::errs() << "\n";
-  llvm::errs() << "Control assertion behavior with one or more of the following options:\n\n";
-  llvm::errs() << " -Xllvm -assert-continue\n";
-  llvm::errs() << "     Continue after any failed assertion\n\n";
+  _abortWithMessage(message);
 }
 
 // This has to be callable in the same way as the macro version,
@@ -86,3 +94,54 @@ void ASSERT_help() {
 int CONDITIONAL_ASSERT_enabled() {
   return (CONDITIONAL_ASSERT_Global_enable_flag != 0);
 }
+
+// MARK: ABORT
+
+namespace {
+/// Similar to PrettyStackTraceString, but formats multi-line strings for
+/// the stack trace.
+class PrettyStackTraceMultilineString : public llvm::PrettyStackTraceEntry {
+  llvm::StringRef Str;
+
+public:
+  PrettyStackTraceMultilineString(llvm::StringRef str) : Str(str) {}
+  void print(llvm::raw_ostream &OS) const override {
+    // For each line, add a leading character and indentation to better match
+    // the formatting of the stack trace.
+    for (auto c : Str.rtrim('\n')) {
+      OS << c;
+      if (c == '\n')
+        OS << "| \t";
+    }
+    OS << '\n';
+  }
+};
+} // end anonymous namespace
+
+static void _abortWithMessage(llvm::StringRef message) {
+  // Use a pretty stack trace to ensure the message gets picked up the
+  // crash reporter.
+  PrettyStackTraceMultilineString trace(message);
+
+  // Also dump to stderr in case pretty backtracing is disabled, and to
+  // allow the message to be seen while attached with a debugger.
+  llvm::errs() << message << '\n';
+
+  abort();
+}
+
+void _ABORT(const char *file, int line, const char *func,
+            llvm::function_ref<void(llvm::raw_ostream &)> message) {
+  llvm::SmallString<0> errorStr;
+  llvm::raw_svector_ostream out(errorStr);
+  out << "Abort: " << "function " << func << " at "
+      << file << ":" << line << "\n";
+  message(out);
+
+  _abortWithMessage(errorStr);
+}
+
+void _ABORT(const char *file, int line, const char *func,
+            llvm::StringRef message) {
+  _ABORT(file, line, func, [&](auto &out) { out << message; });
+}
diff --git a/lib/Basic/BasicBridging.cpp b/lib/Basic/BasicBridging.cpp
index 3432f11a1f70c..abc25424aa5d5 100644
--- a/lib/Basic/BasicBridging.cpp
+++ b/lib/Basic/BasicBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -75,13 +75,13 @@ void BridgedOwnedString::destroy() const {
 }
 
 //===----------------------------------------------------------------------===//
-// MARK: Data
+// MARK: BridgedData
 //===----------------------------------------------------------------------===//
 
-void BridgedData_free(BridgedData data) {
-  if (data.BaseAddress == nullptr)
+void BridgedData::free() const {
+  if (BaseAddress == nullptr)
     return;
-  free(const_cast<char *>(data.BaseAddress));
+  ::free(const_cast<char *>(BaseAddress));
 }
 
 //===----------------------------------------------------------------------===//
@@ -91,9 +91,8 @@ void BridgedData_free(BridgedData data) {
 BridgedCharSourceRangeVector::BridgedCharSourceRangeVector()
     : vector(new std::vector<CharSourceRange>()) {}
 
-void BridgedCharSourceRangeVector::push_back(BridgedCharSourceRange range) {
-  static_cast<std::vector<CharSourceRange> *>(vector)->push_back(
-      range.unbridged());
+void BridgedCharSourceRangeVector::push_back(swift::CharSourceRange range) {
+  static_cast<std::vector<CharSourceRange> *>(vector)->push_back(range);
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/Basic/BlockList.cpp b/lib/Basic/BlockList.cpp
index f89eccbc238d1..0e9af708dc77c 100644
--- a/lib/Basic/BlockList.cpp
+++ b/lib/Basic/BlockList.cpp
@@ -115,8 +115,10 @@ void swift::BlockListStore::Implementation::addConfigureFilePath(StringRef path)
                       SM.getLLVMSourceMgr());
   for (auto DI = Stream.begin(); DI != Stream.end(); ++ DI) {
     assert(DI != Stream.end() && "Failed to read a document");
-    yaml::Node *N = DI->getRoot();
-    for (auto &pair: *dyn_cast<yaml::MappingNode>(N)) {
+    auto *MapNode = dyn_cast<yaml::MappingNode>(DI->getRoot());
+    if (!MapNode)
+      continue;
+    for (auto &pair: *MapNode) {
       std::string key = getScalaString(pair.getKey());
       auto action = llvm::StringSwitch<BlockListAction>(key)
 #define BLOCKLIST_ACTION(X) .Case(#X, BlockListAction::X)
diff --git a/lib/Basic/CMakeLists.txt b/lib/Basic/CMakeLists.txt
index 0f8c65b7857b4..b75e0c8377121 100644
--- a/lib/Basic/CMakeLists.txt
+++ b/lib/Basic/CMakeLists.txt
@@ -59,6 +59,7 @@ add_swift_host_library(swiftBasic STATIC
   ParseableOutput.cpp
   JSONSerialization.cpp
   LangOptions.cpp
+  LangOptionsBridging.cpp
   LoadDynamicLibrary.cpp
   Located.cpp
   Mangler.cpp
@@ -75,6 +76,7 @@ add_swift_host_library(swiftBasic STATIC
   StableHasher.cpp
   Statistic.cpp
   StringExtras.cpp
+  SupportedFeatures.cpp
   TargetInfo.cpp
   TaskQueue.cpp
   ThreadSafeRefCounted.cpp
@@ -133,10 +135,8 @@ if(NOT "${SWIFT_VENDOR}" STREQUAL "")
       " -DSWIFT_VENDOR=\"\\\"${SWIFT_VENDOR}\\\"\"")
 endif()
 
-set(SWIFT_COMPILER_VERSION "" CACHE STRING
-    "The string that identifies the SCM commit(s) for this build")
-
 message(STATUS "Swift compiler version: ${SWIFT_COMPILER_VERSION}")
+message(STATUS "Swift toolchain version: ${SWIFT_TOOLCHAIN_VERSION}")
 message(STATUS "Embedded clang compiler version: ${CLANG_COMPILER_VERSION}")
 
 if(SWIFT_COMPILER_VERSION)
@@ -149,3 +149,7 @@ if(CLANG_COMPILER_VERSION)
     " -DCLANG_COMPILER_VERSION=\"\\\"${CLANG_COMPILER_VERSION}\\\"\"")
 endif()
 
+if(SWIFT_TOOLCHAIN_VERSION)
+  set_property(SOURCE Version.cpp APPEND_STRING PROPERTY COMPILE_FLAGS
+    " -DSWIFT_TOOLCHAIN_VERSION=\"\\\"${SWIFT_TOOLCHAIN_VERSION}\\\"\"")
+endif()
diff --git a/lib/Basic/Feature.cpp b/lib/Basic/Feature.cpp
index b8f5e68b26a87..597f310d2222f 100644
--- a/lib/Basic/Feature.cpp
+++ b/lib/Basic/Feature.cpp
@@ -16,8 +16,8 @@
 
 using namespace swift;
 
-bool swift::isFeatureAvailableInProduction(Feature feature) {
-  switch (feature) {
+bool Feature::isAvailableInProduction() const {
+  switch (kind) {
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
   case Feature::FeatureName:                                                   \
     return true;
@@ -29,8 +29,8 @@ bool swift::isFeatureAvailableInProduction(Feature feature) {
   llvm_unreachable("covered switch");
 }
 
-llvm::StringRef swift::getFeatureName(Feature feature) {
-  switch (feature) {
+llvm::StringRef Feature::getName() const {
+  switch (kind) {
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
   case Feature::FeatureName:                                                   \
     return #FeatureName;
@@ -39,7 +39,7 @@ llvm::StringRef swift::getFeatureName(Feature feature) {
   llvm_unreachable("covered switch");
 }
 
-std::optional<Feature> swift::getUpcomingFeature(llvm::StringRef name) {
+std::optional<Feature> Feature::getUpcomingFeature(llvm::StringRef name) {
   return llvm::StringSwitch<std::optional<Feature>>(name)
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #define UPCOMING_FEATURE(FeatureName, SENumber, Version)                       \
@@ -48,7 +48,7 @@ std::optional<Feature> swift::getUpcomingFeature(llvm::StringRef name) {
       .Default(std::nullopt);
 }
 
-std::optional<Feature> swift::getExperimentalFeature(llvm::StringRef name) {
+std::optional<Feature> Feature::getExperimentalFeature(llvm::StringRef name) {
   return llvm::StringSwitch<std::optional<Feature>>(name)
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #define EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)                     \
@@ -57,8 +57,8 @@ std::optional<Feature> swift::getExperimentalFeature(llvm::StringRef name) {
       .Default(std::nullopt);
 }
 
-std::optional<unsigned> swift::getFeatureLanguageVersion(Feature feature) {
-  switch (feature) {
+std::optional<unsigned> Feature::getLanguageVersion() const {
+  switch (kind) {
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #define UPCOMING_FEATURE(FeatureName, SENumber, Version)                       \
   case Feature::FeatureName:                                                   \
@@ -69,26 +69,29 @@ std::optional<unsigned> swift::getFeatureLanguageVersion(Feature feature) {
   }
 }
 
-bool swift::isFeatureAdoptable(Feature feature) {
-  switch (feature) {
-#define ADOPTABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)
-#define ADOPTABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)
+bool Feature::isMigratable() const {
+  switch (kind) {
+#define MIGRATABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)
+#define MIGRATABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)
+#define MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Name)
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
   case Feature::FeatureName:
 #include "swift/Basic/Features.def"
     return false;
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
-#define ADOPTABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)             \
+#define MIGRATABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)            \
   case Feature::FeatureName:
-#define ADOPTABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)           \
+#define MIGRATABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)          \
+  case Feature::FeatureName:
+#define MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Name)      \
   case Feature::FeatureName:
 #include "swift/Basic/Features.def"
     return true;
   }
 }
 
-bool swift::includeInModuleInterface(Feature feature) {
-  switch (feature) {
+bool Feature::includeInModuleInterface() const {
+  switch (kind) {
 #define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
   case Feature::FeatureName:                                                   \
     return true;
diff --git a/lib/Basic/FileTypes.cpp b/lib/Basic/FileTypes.cpp
index 46430d38fe373..dbe719bdc8677 100644
--- a/lib/Basic/FileTypes.cpp
+++ b/lib/Basic/FileTypes.cpp
@@ -112,7 +112,7 @@ bool file_types::isTextual(ID Id) {
   case file_types::TY_PackageSwiftModuleInterfaceFile:
   case file_types::TY_SwiftOverlayFile:
   case file_types::TY_JSONDependencies:
-  case file_types::TY_JSONFeatures:
+  case file_types::TY_JSONArguments:
   case file_types::TY_SwiftABIDescriptor:
   case file_types::TY_SwiftAPIDescriptor:
   case file_types::TY_ConstValues:
@@ -195,7 +195,7 @@ bool file_types::isAfterLLVM(ID Id) {
   case file_types::TY_PrivateSwiftModuleInterfaceFile:
   case file_types::TY_PackageSwiftModuleInterfaceFile:
   case file_types::TY_JSONDependencies:
-  case file_types::TY_JSONFeatures:
+  case file_types::TY_JSONArguments:
   case file_types::TY_IndexUnitOutputPath:
   case file_types::TY_SwiftABIDescriptor:
   case file_types::TY_SwiftAPIDescriptor:
@@ -257,7 +257,7 @@ bool file_types::isPartOfSwiftCompilation(ID Id) {
   case file_types::TY_YAMLOptRecord:
   case file_types::TY_BitstreamOptRecord:
   case file_types::TY_JSONDependencies:
-  case file_types::TY_JSONFeatures:
+  case file_types::TY_JSONArguments:
   case file_types::TY_IndexUnitOutputPath:
   case file_types::TY_SwiftABIDescriptor:
   case file_types::TY_SwiftAPIDescriptor:
@@ -321,7 +321,7 @@ bool file_types::isProducedFromDiagnostics(ID Id) {
   case file_types::TY_YAMLOptRecord:
   case file_types::TY_BitstreamOptRecord:
   case file_types::TY_JSONDependencies:
-  case file_types::TY_JSONFeatures:
+  case file_types::TY_JSONArguments:
   case file_types::TY_IndexUnitOutputPath:
   case file_types::TY_SwiftABIDescriptor:
   case file_types::TY_SwiftAPIDescriptor:
diff --git a/lib/Basic/LangOptions.cpp b/lib/Basic/LangOptions.cpp
index a65755018c10e..114b81a20ae53 100644
--- a/lib/Basic/LangOptions.cpp
+++ b/lib/Basic/LangOptions.cpp
@@ -51,11 +51,6 @@ LangOptions::LangOptions() {
   disableFeature(Feature::ExtensionMacros);
 #endif
 
-  // Note: Introduce default-on language options here.
-  enableFeature(Feature::NoncopyableGenerics);
-  enableFeature(Feature::BorrowingSwitch);
-  enableFeature(Feature::MoveOnlyPartialConsumption);
-
   // Enable any playground options that are enabled by default.
 #define PLAYGROUND_OPTION(OptionName, Description, DefaultOn, HighPerfOn) \
   if (DefaultOn) \
@@ -257,6 +252,9 @@ LangOptions::getPlatformConditionValue(PlatformConditionKind Kind) const {
 
 bool LangOptions::
 checkPlatformCondition(PlatformConditionKind Kind, StringRef Value) const {
+  // Note: BridgedASTContext_enumerateBuildConfigurationEntries has a redundant
+  // copy of these special cases.
+
   // Check a special case that "macOS" is an alias of "OSX".
   if (Kind == PlatformConditionKind::OS && Value == "macOS")
     return checkPlatformCondition(Kind, "OSX");
@@ -298,15 +296,14 @@ bool LangOptions::FeatureState::isEnabled() const {
   return state == FeatureState::Kind::Enabled;
 }
 
-bool LangOptions::FeatureState::isEnabledForAdoption() const {
-  ASSERT(isFeatureAdoptable(feature) &&
-         "You forgot to make the feature adoptable!");
+bool LangOptions::FeatureState::isEnabledForMigration() const {
+  ASSERT(feature.isMigratable() && "You forgot to make the feature migratable!");
 
-  return state == FeatureState::Kind::EnabledForAdoption;
+  return state == FeatureState::Kind::EnabledForMigration;
 }
 
 LangOptions::FeatureStateStorage::FeatureStateStorage()
-    : states(numFeatures(), FeatureState::Kind::Off) {}
+    : states(Feature::getNumFeatures(), FeatureState::Kind::Off) {}
 
 void LangOptions::FeatureStateStorage::setState(Feature feature,
                                                 FeatureState::Kind state) {
@@ -327,7 +324,7 @@ LangOptions::FeatureState LangOptions::getFeatureState(Feature feature) const {
   if (state.isEnabled())
     return state;
 
-  if (auto version = getFeatureLanguageVersion(feature)) {
+  if (auto version = feature.getLanguageVersion()) {
     if (isSwiftVersionAtLeast(*version)) {
       return FeatureState(feature, FeatureState::Kind::Enabled);
     }
@@ -336,12 +333,18 @@ LangOptions::FeatureState LangOptions::getFeatureState(Feature feature) const {
   return state;
 }
 
-bool LangOptions::hasFeature(Feature feature) const {
-  if (featureStates.getState(feature).isEnabled())
+bool LangOptions::hasFeature(Feature feature, bool allowMigration) const {
+  auto state = featureStates.getState(feature);
+  if (state.isEnabled())
     return true;
 
-  if (auto version = getFeatureLanguageVersion(feature))
-    return isSwiftVersionAtLeast(*version);
+  if (auto version = feature.getLanguageVersion()) {
+    if (isSwiftVersionAtLeast(*version))
+      return true;
+  }
+
+  if (allowMigration && state.isEnabledForMigration())
+    return true;
 
   return false;
 }
@@ -358,13 +361,18 @@ bool LangOptions::hasFeature(llvm::StringRef featureName) const {
   return false;
 }
 
-void LangOptions::enableFeature(Feature feature, bool forAdoption) {
-  if (forAdoption) {
-    ASSERT(isFeatureAdoptable(feature));
-    featureStates.setState(feature, FeatureState::Kind::EnabledForAdoption);
-  } else {
-    featureStates.setState(feature, FeatureState::Kind::Enabled);
+bool LangOptions::isMigratingToFeature(Feature feature) const {
+  return featureStates.getState(feature).isEnabledForMigration();
+}
+
+void LangOptions::enableFeature(Feature feature, bool forMigration) {
+  if (forMigration) {
+    ASSERT(feature.isMigratable());
+    featureStates.setState(feature, FeatureState::Kind::EnabledForMigration);
+    return;
   }
+
+  featureStates.setState(feature, FeatureState::Kind::Enabled);
 }
 
 void LangOptions::disableFeature(Feature feature) {
diff --git a/lib/Basic/LangOptionsBridging.cpp b/lib/Basic/LangOptionsBridging.cpp
new file mode 100644
index 0000000000000..5ccc2a8ea1df0
--- /dev/null
+++ b/lib/Basic/LangOptionsBridging.cpp
@@ -0,0 +1,265 @@
+//===--- Bridging/LangOptsBridging.cpp ------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/AST/ASTBridging.h"
+
+#include "swift/Basic/LangOptions.h"
+
+using namespace swift;
+
+bool BridgedLangOptions_hasFeature(BridgedLangOptions cLangOpts,
+                                   BridgedFeature feature) {
+  return cLangOpts.unbridged().hasFeature((Feature)feature);
+}
+
+
+unsigned BridgedLangOptions::getTargetPointerBitWidth() const {
+  return unbridged().Target.isArch64Bit()   ? 64
+         : unbridged().Target.isArch32Bit() ? 32
+         : unbridged().Target.isArch16Bit() ? 16
+                                            : 0;
+}
+
+BridgedEndianness BridgedLangOptions::getTargetEndianness() const {
+  return unbridged().Target.isLittleEndian() ? EndianLittle : EndianBig;
+}
+
+bool BridgedLangOptions::getAttachCommentsToDecls() const {
+  return unbridged().AttachCommentsToDecls;
+}
+
+/// Convert an array of numbers into a form we can use in Swift.
+namespace {
+template <typename Arr>
+SwiftInt convertArray(const Arr &array, SwiftInt **cElements) {
+  SwiftInt numElements = array.size();
+  *cElements = (SwiftInt *)malloc(sizeof(SwiftInt) * numElements);
+  for (SwiftInt i = 0; i != numElements; ++i)
+    (*cElements)[i] = array[i];
+  return numElements;
+}
+} // namespace
+
+void deallocateIntBuffer(SwiftInt *_Nullable cComponents) { free(cComponents); }
+
+SwiftInt
+BridgedLangOptions_getLanguageVersion(BridgedLangOptions cLangOpts,
+                                      SwiftInt **cComponents) {
+  auto theVersion = cLangOpts.unbridged().EffectiveLanguageVersion;
+  return convertArray(theVersion, cComponents);
+}
+
+SwiftInt
+BridgedLangOptions_getCompilerVersion(BridgedLangOptions cLangOpts,
+                                      SwiftInt **cComponents) {
+  auto theVersion = version::Version::getCurrentLanguageVersion();
+  return convertArray(theVersion, cComponents);
+}
+
+SwiftInt BridgedLangOptions_getTargetAtomicBitWidths(
+    BridgedLangOptions cLangOpts, SwiftInt *_Nullable *_Nonnull cElements) {
+  return convertArray(cLangOpts.unbridged().getAtomicBitWidthValues(),
+                      cElements);
+}
+
+namespace {
+
+/// Describe behaviors that should prevent an attribute from being shown.
+///
+/// This is DeclAttrBehaviors, but with irrelevent values set to zero.
+enum DeclAttrBehaviorsNotShown : uint64_t {
+  /// Whether this attribute is only valid when concurrency is enabled.
+  ConcurrencyOnly = 0,
+
+  /// True if multiple instances of this attribute are allowed on a single
+  /// declaration.
+  AllowMultipleAttributes = 0,
+
+  /// True if this is a decl modifier - i.e., that it should not be spelled
+  /// with an @.
+  DeclModifier = 1ull << 2,
+
+  /// True if this is a long attribute that should be printed on its own line.
+  ///
+  /// Currently has no effect on DeclModifier attributes.
+  LongAttribute = 0,
+
+  /// True if this shouldn't be serialized.
+  NotSerialized = 0,
+
+  /// True if this attribute is only valid when parsing a .sil file.
+  SILOnly = 1ull << 5,
+
+  /// The attribute should be reported by parser as unknown.
+  RejectByParser = 1ull << 6,
+
+  /// Whether client code cannot use the attribute. Hides it in code completion.
+  UserInaccessible = 1ull << 7,
+
+  /// Whether adding this attribute can break API
+  APIBreakingToAdd = 0,
+
+  /// Whether removing this attribute can break API
+  APIBreakingToRemove = 0,
+
+  /// Whether adding this attribute can break ABI
+  ABIBreakingToAdd = 0,
+
+  /// Whether removing this attribute can break ABI
+  ABIBreakingToRemove = 0,
+
+  /// The opposite of APIBreakingToAdd
+  APIStableToAdd = 0,
+
+  /// The opposite of APIBreakingToRemove
+  APIStableToRemove = 0,
+
+  /// The opposite of ABIBreakingToAdd
+  ABIStableToAdd = 0,
+
+  /// The opposite of ABIBreakingToRemove
+  ABIStableToRemove = 0,
+
+  /// Attribute should not be used in an \c \@abi attribute. Use for
+  /// attributes which cannot affect mangled names, even indirectly, and
+  /// which either don't affect ABI or where ABI-only declarations get their
+  /// behavior from their API counterpart.
+  ForbiddenInABIAttr = 0,
+
+  /// Attribute can be used without restrictions in an \c \@abi attribute.
+  /// Use for attributes which affect mangled names but otherwise don't alter
+  /// the ABI, or ones where the \c ABIDeclChecker manually implements
+  /// special checking logic (e.g. because several different attributes
+  /// contribute to the same aspect of ABI in some complicated way).
+  UnconstrainedInABIAttr = 0,
+
+  /// Attribute can be used in an \c \@abi attribute, but must match
+  /// equivalent on API decl. Use for attributes which affect both mangled
+  /// names and other parts of the ABI such that the declaration can only be
+  /// valid if they match.
+  EquivalentInABIAttr = 0,
+
+  /// Use for attributes which are \em only valid on declarations that cannot
+  /// have an \c @abi attribute, such as \c ImportDecl .
+  UnreachableInABIAttr = 0,
+};
+
+}
+
+void BridgedLangOptions_enumerateBuildConfigurationEntries(
+    BridgedLangOptions cLangOpts,
+    void * _Nonnull callbackContext,
+    void (* _Nonnull callback)(
+        BridgedLangOptions cLangOpts, void * _Nonnull callbackContext,
+        BuildConfigurationKey key, BridgedStringRef value)) {
+  const LangOptions &langOpts = cLangOpts.unbridged();
+
+  // Enumerate custom conditions.
+  for (const auto &customCondition: langOpts.getCustomConditionalCompilationFlags()) {
+    callback(cLangOpts, callbackContext, BCKCustomCondition,
+             StringRef(customCondition));
+  }
+
+  // Enumerate features that are enabled.
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
+  if (langOpts.hasFeature(Feature::FeatureName))                               \
+    callback(cLangOpts, callbackContext, BCKFeature, StringRef(#FeatureName));
+#include "swift/Basic/Features.def"
+
+  // Enumerate attributes that are available.
+#define DECL_ATTR(SPELLING, CLASS, REQUIREMENTS, BEHAVIORS, CODE)              \
+  if ((BEHAVIORS) == 0) \
+    callback(cLangOpts, callbackContext, BCKAttribute, StringRef(#SPELLING));
+#include "swift/AST/DeclAttr.def"
+
+#define SIL_TYPE_ATTR(X, C)
+#define TYPE_ATTR(SPELLING, CLASS)                                             \
+  callback(cLangOpts, callbackContext, BCKAttribute, StringRef(#SPELLING));
+#include "swift/AST/TypeAttr.def"
+
+  // Deal with all of the target platform/architecture information.
+  for (const auto &[kind, value] : langOpts.getPlatformConditionValues()) {
+    switch (kind) {
+      case PlatformConditionKind::OS:
+        callback(cLangOpts, callbackContext, BCKTargetOSName, StringRef(value));
+
+        // Special case that macOS is an alias of OSX.
+        if (value == "OSX") {
+          callback(cLangOpts, callbackContext, BCKTargetOSName,
+                   StringRef("macOS"));
+        }
+        break;
+
+      case PlatformConditionKind::Arch:
+        callback(cLangOpts, callbackContext, BCKTargetArchitecture, StringRef(value));
+        break;
+
+      case PlatformConditionKind::Runtime:
+        callback(cLangOpts, callbackContext, BCKTargetRuntime, StringRef(value));
+        break;
+
+      case PlatformConditionKind::TargetEnvironment:
+        callback(cLangOpts, callbackContext, BCKTargetEnvironment,
+                 StringRef(value));
+
+        // When compiling for iOS we consider "macCatalyst" to be a
+        // synonym of "macabi". This enables the use of
+        // #if targetEnvironment(macCatalyst) as a compilation
+        // condition for macCatalyst.
+        if (value == "macabi" && langOpts.Target.isiOS()) {
+          callback(cLangOpts, callbackContext, BCKTargetEnvironment,
+                   StringRef("macCatalyst"));
+        }
+        break;
+
+      case PlatformConditionKind::PtrAuth:
+        callback(cLangOpts, callbackContext, BCKTargetPointerAuthenticationScheme,
+                 StringRef(value));
+        break;
+
+      case PlatformConditionKind::Endianness:
+      case PlatformConditionKind::PointerBitWidth:
+      case PlatformConditionKind::CanImport:
+      case PlatformConditionKind::HasAtomicBitWidth:
+        // Handled separately.
+        break;
+    }
+  }
+
+  // Object file format.
+  llvm::Triple triple(langOpts.Target.getTriple());
+  switch (triple.getObjectFormat()) {
+    case llvm::Triple::ObjectFormatType::COFF:
+      callback(cLangOpts, callbackContext, BCKTargetObjectFileFormat,
+               StringRef("COFF"));
+      break;
+    case llvm::Triple::ObjectFormatType::ELF:
+      callback(cLangOpts, callbackContext, BCKTargetObjectFileFormat,
+               StringRef("ELF"));
+      break;
+    case llvm::Triple::ObjectFormatType::MachO:
+      callback(cLangOpts, callbackContext, BCKTargetObjectFileFormat,
+               StringRef("MachO"));
+      break;
+    case llvm::Triple::ObjectFormatType::SPIRV:
+      callback(cLangOpts, callbackContext, BCKTargetObjectFileFormat,
+               StringRef("SPIRV"));
+      break;
+    case llvm::Triple::ObjectFormatType::Wasm:
+      callback(cLangOpts, callbackContext, BCKTargetObjectFileFormat,
+               StringRef("Wasm"));
+      break;
+    default:
+      // Ignore others.
+      break;
+  }
+}
diff --git a/lib/Basic/Mangler.cpp b/lib/Basic/Mangler.cpp
index 35bad0b1ad60d..f8f6f5c2a18e0 100644
--- a/lib/Basic/Mangler.cpp
+++ b/lib/Basic/Mangler.cpp
@@ -12,6 +12,7 @@
 
 #include "swift/Basic/Mangler.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Demangling/Demangler.h"
 #include "swift/Demangling/ManglingMacros.h"
 #include "swift/Demangling/Punycode.h"
@@ -201,22 +202,25 @@ void Mangler::verify(StringRef nameStr, ManglingFlavor Flavor) {
   Demangler Dem;
   NodePointer Root = Dem.demangleSymbol(nameStr);
   if (!Root || treeContains(Root, Node::Kind::Suffix)) {
-    llvm::errs() << "Can't demangle: " << nameStr << '\n';
-    abort();
+    ABORT([&](auto &out) {
+      out << "Can't demangle: " << nameStr;
+    });
   }
   auto mangling = mangleNode(Root, Flavor);
   if (!mangling.isSuccess()) {
-    llvm::errs() << "Can't remangle: " << nameStr << '\n';
-    abort();
+    ABORT([&](auto &out) {
+      out << "Can't remangle: " << nameStr;
+    });
   }
   std::string Remangled = mangling.result();
   if (Remangled == nameStr)
     return;
 
-  llvm::errs() << "Remangling failed:\n"
-                  "original     = " << nameStr << "\n"
-                  "remangled    = " << Remangled << "\n";
-  abort();
+  ABORT([&](auto &out) {
+    out << "Remangling failed:\n";
+    out << "original     = " << nameStr << "\n";
+    out << "remangled    = " << Remangled;
+  });
 }
 
 void Mangler::appendIdentifier(StringRef ident, bool allowRawIdentifiers) {
diff --git a/lib/Basic/Platform.cpp b/lib/Basic/Platform.cpp
index 4b6b827ef6594..8906bce54be32 100644
--- a/lib/Basic/Platform.cpp
+++ b/lib/Basic/Platform.cpp
@@ -117,23 +117,32 @@ bool swift::tripleRequiresRPathForSwiftLibrariesInOS(
     // macOS versions before 10.14.4 don't have Swift in the OS
     // (the linker still uses an rpath-based install name until 10.15).
     // macOS versions before 12.0 don't have _Concurrency in the OS.
-    return triple.isMacOSXVersionLT(12, 0);
+    // macOS versions before 26.0 don't have Span in stdlib.
+    return triple.isMacOSXVersionLT(26, 0);
   }
 
   if (triple.isiOS()) {
     // iOS versions before 12.2 don't have Swift in the OS.
     // iOS versions before 15.0 don't have _Concurrency in the OS.
-    return triple.isOSVersionLT(15, 0);
+    // iOS versions before 26.0 don't have Span in stdlib.
+    return triple.isOSVersionLT(26, 0);
   }
 
   if (triple.isWatchOS()) {
     // watchOS versions before 5.2 don't have Swift in the OS.
     // watchOS versions before 8.0 don't have _Concurrency in the OS.
-    return triple.isOSVersionLT(8, 0);
+    // watchOS versions before 26.0 don't have Span in stdlib.
+    return triple.isOSVersionLT(26, 0);
+  }
+
+  if (triple.isTvOS()) {
+    // tvOS versions before 26.0 don't have Span in stdlib.
+    return triple.isOSVersionLT(26, 0);
   }
 
   if (triple.isXROS()) {
-    return triple.isOSVersionLT(1, 0);
+    // visionOS versions before 26.0 don't have Span in stdlib.
+    return triple.isOSVersionLT(26, 0);
   }
 
   // Other platforms don't have Swift installed as part of the OS by default.
@@ -273,11 +282,29 @@ StringRef swift::getPlatformNameForTriple(const llvm::Triple &triple) {
     return "none";
   case llvm::Triple::UEFI:
   case llvm::Triple::LiteOS:
+  case llvm::Triple::Managarm:
     llvm_unreachable("unsupported OS");
   }
   llvm_unreachable("unsupported OS");
 }
 
+llvm::VersionTuple swift::getVersionForTriple(const llvm::Triple &triple) {
+  if (triple.isMacOSX()) {
+    llvm::VersionTuple OSVersion;
+    triple.getMacOSXVersion(OSVersion);
+    return OSVersion;
+  } else if (triple.isiOS()) {
+    return triple.getiOSVersion();
+  } else if (triple.isWatchOS()) {
+    return triple.getOSVersion();
+  } else if (triple.isXROS()) {
+    return triple.getOSVersion();
+  } else if (triple.isOSWindows()) {
+    return triple.getOSVersion();
+  }
+  return llvm::VersionTuple(/*Major=*/0, /*Minor=*/0, /*Subminor=*/0);
+}
+
 StringRef swift::getMajorArchitectureName(const llvm::Triple &Triple) {
   if (Triple.isOSLinux()) {
     switch (Triple.getSubArch()) {
@@ -291,6 +318,13 @@ StringRef swift::getMajorArchitectureName(const llvm::Triple &Triple) {
       break;
     }
   }
+
+  if (Triple.isOSOpenBSD()) {
+    if (Triple.getArchName() == "amd64") {
+      return "x86_64";
+    }
+  }
+
   return Triple.getArchName();
 }
 
@@ -422,6 +456,11 @@ llvm::Triple swift::getTargetSpecificModuleTriple(const llvm::Triple &triple) {
     return swift::getUnversionedTriple(triple);
   }
 
+  if (triple.isOSOpenBSD()) {
+    StringRef arch = swift::getMajorArchitectureName(triple);
+    return llvm::Triple(arch, triple.getVendorName(), triple.getOSName());
+  }
+
   // Other platforms get no normalization.
   return triple;
 }
@@ -836,6 +875,37 @@ llvm::VersionTuple swift::getTargetSDKVersion(clang::DarwinSDKInfo &SDKInfo,
   return SDKVersion;
 }
 
+std::optional<llvm::Triple>
+swift::getCanonicalTriple(const llvm::Triple &triple) {
+  llvm::Triple Result = triple;
+  // Non-darwin targets do not require canonicalization.
+  if (!triple.isOSDarwin())
+    return Result;
+
+  // If the OS versions stay the same, return back the same triple.
+  const llvm::VersionTuple inputOSVersion = triple.getOSVersion();
+  const bool isOSVersionInValidRange =
+      llvm::Triple::isValidVersionForOS(triple.getOS(), inputOSVersion);
+  const llvm::VersionTuple canonicalVersion =
+      llvm::Triple::getCanonicalVersionForOS(
+          triple.getOS(), triple.getOSVersion(), isOSVersionInValidRange);
+  if (canonicalVersion == triple.getOSVersion())
+    return Result;
+
+  const std::string inputOSName = triple.getOSName().str();
+  const std::string inputOSVersionAsStr = inputOSVersion.getAsString();
+  const int platformNameLength =
+      inputOSName.size() - inputOSVersionAsStr.size();
+  if (!StringRef(inputOSName).ends_with(inputOSVersionAsStr) ||
+      (platformNameLength <= 0))
+    return std::nullopt;
+
+  llvm::SmallString<64> buffer(inputOSName.substr(0, platformNameLength));
+  buffer.append(canonicalVersion.getAsString());
+  Result.setOSName(buffer.str());
+  return Result;
+}
+
 static std::string getPlistEntry(const llvm::Twine &Path, StringRef KeyName) {
   auto BufOrErr = llvm::MemoryBuffer::getFile(Path);
   if (!BufOrErr) {
diff --git a/lib/Basic/PrettyStackTrace.cpp b/lib/Basic/PrettyStackTrace.cpp
index 9ea117b67a23e..78d4e8d277405 100644
--- a/lib/Basic/PrettyStackTrace.cpp
+++ b/lib/Basic/PrettyStackTrace.cpp
@@ -18,6 +18,7 @@
 #include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Basic/QuotedString.h"
 #include "swift/Basic/Version.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/raw_ostream.h"
 
diff --git a/lib/Basic/Program.cpp b/lib/Basic/Program.cpp
index 1d53cdef6b300..473b41a860ef1 100644
--- a/lib/Basic/Program.cpp
+++ b/lib/Basic/Program.cpp
@@ -123,11 +123,15 @@ swift::ExecuteWithPipe(llvm::StringRef program,
   posix_spawn_file_actions_t FileActions;
   posix_spawn_file_actions_init(&FileActions);
 
+  // Redirect file descriptors...
   posix_spawn_file_actions_adddup2(&FileActions, p1.read, STDIN_FILENO);
-  posix_spawn_file_actions_addclose(&FileActions, p1.write);
-
   posix_spawn_file_actions_adddup2(&FileActions, p2.write, STDOUT_FILENO);
+
+  // Close all file descriptors, not needed as we duped them to the stdio.
+  posix_spawn_file_actions_addclose(&FileActions, p1.read);
+  posix_spawn_file_actions_addclose(&FileActions, p1.write);
   posix_spawn_file_actions_addclose(&FileActions, p2.read);
+  posix_spawn_file_actions_addclose(&FileActions, p2.write);
 
   // Spawn the subtask.
   int error = posix_spawn(&pid, progCStr, &FileActions, nullptr,
@@ -156,13 +160,16 @@ swift::ExecuteWithPipe(llvm::StringRef program,
 
   // Child process.
   case 0:
-    close(p1.write);
-    close(p2.read);
-
     // Redirect file descriptors...
     dup2(p1.read, STDIN_FILENO);
     dup2(p2.write, STDOUT_FILENO);
 
+    // Close all file descriptors, not needed as we duped them to the stdio.
+    close(p1.read);
+    close(p1.write);
+    close(p2.read);
+    close(p2.write);
+
     // Execute the program.
     if (envp) {
       execve(progCStr, const_cast<char **>(argv), const_cast<char **>(envp));
@@ -180,11 +187,12 @@ swift::ExecuteWithPipe(llvm::StringRef program,
 
   // Parent process.
   default:
+    close(p1.read);
+    close(p2.write);
     break;
   }
 #endif
-  close(p1.read);
-  close(p2.write);
+
   llvm::sys::ProcessInfo proc;
   proc.Pid = pid;
   proc.Process = pid;
diff --git a/lib/Basic/SourceLoc.cpp b/lib/Basic/SourceLoc.cpp
index 03b9ce15f1823..682399a139a83 100644
--- a/lib/Basic/SourceLoc.cpp
+++ b/lib/Basic/SourceLoc.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -120,7 +120,7 @@ void SourceManager::createVirtualFile(SourceLoc Loc, StringRef Name,
   CharSourceRange Range = CharSourceRange(Loc, Length);
 
   // Skip if this range has already been added
-  VirtualFile &File = VirtualFiles[Range.getEnd().Value.getPointer()];
+  VirtualFile &File = VirtualFiles[Range.getEnd().getPointer()];
   if (File.Range.isValid()) {
     assert(Name == StringRef(File.Name));
     assert(LineOffset == File.LineOffset);
@@ -132,8 +132,8 @@ void SourceManager::createVirtualFile(SourceLoc Loc, StringRef Name,
   File.Name = Name.str();
   File.LineOffset = LineOffset;
 
-  if (CachedVFile.first && Range.contains(SourceLoc(llvm::SMLoc::getFromPointer(
-                               CachedVFile.first)))) {
+  if (CachedVFile.first &&
+      Range.contains(SourceLoc::getFromPointer(CachedVFile.first))) {
     CachedVFile = {nullptr, nullptr};
   }
 }
@@ -143,7 +143,7 @@ bool SourceManager::openVirtualFile(SourceLoc loc, StringRef name,
   CharSourceRange fullRange = getRangeForBuffer(findBufferContainingLoc(loc));
   SourceLoc end;
 
-  auto nextRangeIter = VirtualFiles.upper_bound(loc.Value.getPointer());
+  auto nextRangeIter = VirtualFiles.upper_bound(loc.getPointer());
   if (nextRangeIter != VirtualFiles.end() &&
       fullRange.contains(nextRangeIter->second.Range.getStart())) {
     const VirtualFile &existingFile = nextRangeIter->second;
@@ -160,7 +160,7 @@ bool SourceManager::openVirtualFile(SourceLoc loc, StringRef name,
   }
 
   CharSourceRange range = CharSourceRange(*this, loc, end);
-  VirtualFiles[end.Value.getPointer()] = {range, name.str(), lineOffset};
+  VirtualFiles[end.getPointer()] = {range, name.str(), lineOffset};
   CachedVFile = {nullptr, nullptr};
   return true;
 }
@@ -183,16 +183,16 @@ void SourceManager::closeVirtualFile(SourceLoc end) {
   CharSourceRange oldRange = virtualFile->Range;
   virtualFile->Range = CharSourceRange(*this, virtualFile->Range.getStart(),
                                        end);
-  VirtualFiles[end.Value.getPointer()] = std::move(*virtualFile);
+  VirtualFiles[end.getPointer()] = std::move(*virtualFile);
 
-  bool existed = VirtualFiles.erase(oldRange.getEnd().Value.getPointer());
+  bool existed = VirtualFiles.erase(oldRange.getEnd().getPointer());
   assert(existed);
   (void)existed;
 }
 
 const SourceManager::VirtualFile *
 SourceManager::getVirtualFile(SourceLoc Loc) const {
-  const char *p = Loc.Value.getPointer();
+  const char *p = Loc.getPointer();
 
   if (CachedVFile.first == p)
     return CachedVFile.second;
@@ -328,7 +328,7 @@ StringRef SourceManager::getIdentifierForBuffer(
 
 CharSourceRange SourceManager::getRangeForBuffer(unsigned bufferID) const {
   auto *buffer = LLVMSourceMgr.getMemoryBuffer(bufferID);
-  SourceLoc start{llvm::SMLoc::getFromPointer(buffer->getBufferStart())};
+  auto start = SourceLoc::getFromPointer(buffer->getBufferStart());
   return CharSourceRange(start, buffer->getBufferSize());
 }
 
@@ -336,10 +336,10 @@ unsigned SourceManager::getLocOffsetInBuffer(SourceLoc Loc,
                                              unsigned BufferID) const {
   assert(Loc.isValid() && "location should be valid");
   auto *Buffer = LLVMSourceMgr.getMemoryBuffer(BufferID);
-  assert(Loc.Value.getPointer() >= Buffer->getBuffer().begin() &&
-         Loc.Value.getPointer() <= Buffer->getBuffer().end() &&
+  assert(Loc.getPointer() >= Buffer->getBuffer().begin() &&
+         Loc.getPointer() <= Buffer->getBuffer().end() &&
          "Location is not from the specified buffer");
-  return Loc.Value.getPointer() - Buffer->getBuffer().begin();
+  return Loc.getPointer() - Buffer->getBuffer().begin();
 }
 
 unsigned SourceManager::getByteDistance(SourceLoc Start, SourceLoc End) const {
@@ -348,13 +348,13 @@ unsigned SourceManager::getByteDistance(SourceLoc Start, SourceLoc End) const {
 #ifndef NDEBUG
   unsigned BufferID = findBufferContainingLoc(Start);
   auto *Buffer = LLVMSourceMgr.getMemoryBuffer(BufferID);
-  assert(End.Value.getPointer() >= Buffer->getBuffer().begin() &&
-         End.Value.getPointer() <= Buffer->getBuffer().end() &&
+  assert(End.getPointer() >= Buffer->getBuffer().begin() &&
+         End.getPointer() <= Buffer->getBuffer().end() &&
          "End location is not from the same buffer");
 #endif
   // When we have a rope buffer, could be implemented in terms of
   // getLocOffsetInBuffer().
-  return End.Value.getPointer() - Start.Value.getPointer();
+  return End.getPointer() - Start.getPointer();
 }
 
 unsigned SourceManager::getColumnInBuffer(SourceLoc Loc,
@@ -482,7 +482,7 @@ namespace {
 
 std::optional<unsigned>
 SourceManager::findBufferContainingLocInternal(SourceLoc Loc) const {
-  assert(Loc.isValid());
+  ASSERT(Loc.isValid());
 
   // If the cache is out-of-date, update it now.
   unsigned numBuffers = LLVMSourceMgr.getNumBuffers();
@@ -512,10 +512,10 @@ SourceManager::findBufferContainingLocInternal(SourceLoc Loc) const {
     auto less_equal = std::less_equal<const char *>();
     auto buffer = LLVMSourceMgr.getMemoryBuffer(bufferID);
 
-    return less_equal(buffer->getBufferStart(), Loc.Value.getPointer()) &&
+    return less_equal(buffer->getBufferStart(), Loc.getPointer()) &&
            // Use <= here so that a pointer to the null at the end of the
            // buffer is included as part of the buffer.
-           less_equal(Loc.Value.getPointer(), buffer->getBufferEnd());
+           less_equal(Loc.getPointer(), buffer->getBufferEnd());
   };
 
   // Check the last buffer we looked in.
@@ -569,15 +569,15 @@ SourceRange SourceRange::combine(ArrayRef<SourceRange> ranges) {
 }
 
 void SourceRange::widen(SourceRange Other) {
-  if (Other.Start.Value.getPointer() < Start.Value.getPointer())
+  if (Other.Start.getPointer() < Start.getPointer())
     Start = Other.Start;
-  if (Other.End.Value.getPointer() > End.Value.getPointer())
+  if (Other.End.getPointer() > End.getPointer())
     End = Other.End;
 }
 
 bool SourceRange::contains(SourceLoc Loc) const {
-  return Start.Value.getPointer() <= Loc.Value.getPointer() &&
-         Loc.Value.getPointer() <= End.Value.getPointer();
+  return Start.getPointer() <= Loc.getPointer() &&
+         Loc.getPointer() <= End.getPointer();
 }
 
 bool SourceRange::overlaps(SourceRange Other) const {
diff --git a/lib/Basic/Statistic.cpp b/lib/Basic/Statistic.cpp
index 4a20de17501c0..f270fe9ed690c 100644
--- a/lib/Basic/Statistic.cpp
+++ b/lib/Basic/Statistic.cpp
@@ -33,7 +33,7 @@
 #ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>
 #endif
-#ifdef HAVE_SYS_RESOURCE_H
+#if HAVE_GETRUSAGE && !defined(__HAIKU__)
 #include <sys/resource.h>
 #endif
 #ifdef HAVE_PROC_PID_RUSAGE
@@ -383,7 +383,7 @@ void UnifiedStatsReporter::recordJobMaxRSS(long rss) {
 }
 
 int64_t UnifiedStatsReporter::getChildrenMaxResidentSetSize() {
-#if defined(HAVE_GETRUSAGE) && !defined(__HAIKU__)
+#if HAVE_GETRUSAGE && !defined(__HAIKU__)
   struct rusage RU;
   ::getrusage(RUSAGE_CHILDREN, &RU);
   int64_t M = static_cast<int64_t>(RU.ru_maxrss);
diff --git a/lib/Basic/SupportedFeatures.cpp b/lib/Basic/SupportedFeatures.cpp
new file mode 100644
index 0000000000000..4ba21f8a3c03a
--- /dev/null
+++ b/lib/Basic/SupportedFeatures.cpp
@@ -0,0 +1,145 @@
+//===--- SupportedFeatures.cpp - Supported features printing --------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include <array>
+#include <vector>
+
+#include "swift/AST/DiagnosticGroups.h"
+#include "swift/Basic/Feature.h"
+#include "swift/Frontend/Frontend.h"
+
+#include "llvm/Support/raw_ostream.h"
+
+using namespace swift;
+
+namespace swift {
+namespace features {
+
+/// The subset of diagnostic groups (called categories by the diagnostic machinery) whose diagnostics should be
+/// considered to be part of the migration for this feature.
+///
+///  When making a feature migratable, ensure that all of the warnings that are used to drive the migration are
+///  part of a diagnostic group, and put that diagnostic group into the list for that feature here.
+static std::vector<DiagGroupID> migratableCategories(Feature feature) {
+  switch (feature) {
+    case Feature::InnerKind::ExistentialAny:
+      return { DiagGroupID::ExistentialAny };
+    case Feature::InnerKind::InferIsolatedConformances:
+      return { DiagGroupID::IsolatedConformances };
+    case Feature::InnerKind::MemberImportVisibility:
+      return { DiagGroupID::MemberImportVisibility };
+    case Feature::InnerKind::NonisolatedNonsendingByDefault:
+      return { DiagGroupID::NonisolatedNonsendingByDefault };
+    case Feature::InnerKind::StrictMemorySafety:
+      return { DiagGroupID::StrictMemorySafety };
+
+    // Provide unreachable cases for all of the non-migratable features.
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description) case Feature::FeatureName:
+#define MIGRATABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)
+#define MIGRATABLE_EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)
+#define MIGRATABLE_OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Name)
+#include "swift/Basic/Features.def"
+    llvm_unreachable("Not a migratable feature");
+  }
+}
+
+/// For optional language features, return the flag name used by the compiler to enable the feature. For all others,
+/// returns an empty optional.
+static std::optional<std::string_view> optionalFlagName(Feature feature) {
+  switch (feature) {
+  case Feature::StrictMemorySafety:
+    return "-strict-memory-safety";
+
+  case Feature::LibraryEvolution:
+    return "-enable-library-evolution";
+
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description) case Feature::FeatureName:
+#define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Description)
+#include "swift/Basic/Features.def"
+    return std::nullopt;
+  }
+}
+
+/// Print information about what features upcoming/experimental are
+/// supported by the compiler.
+/// The information includes whether a feature is adoptable and for
+/// upcoming features - what is the first mode it's introduced.
+void printSupportedFeatures(llvm::raw_ostream &out) {
+  std::array optional{
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
+#define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Description) Feature::FeatureName,
+#include "swift/Basic/Features.def"
+  };
+
+  std::array upcoming{
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
+#define UPCOMING_FEATURE(FeatureName, SENumber, Version) Feature::FeatureName,
+#include "swift/Basic/Features.def"
+  };
+
+  std::vector<swift::Feature> experimental{{
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
+#define EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd) Feature::FeatureName,
+#include "swift/Basic/Features.def"
+  }};
+
+  // Include only experimental features that are available in production.
+  llvm::erase_if(experimental, [](auto &feature) {
+    return !feature.isAvailableInProduction();
+  });
+
+  out << "{\n";
+  auto printFeature = [&out](const Feature &feature) {
+    out << "      ";
+    out << "{ \"name\": \"" << feature.getName() << "\"";
+    if (feature.isMigratable()) {
+      out << ", \"migratable\": true";
+
+      auto categories = migratableCategories(feature);
+      out << ", \"categories\": [";
+      llvm::interleave(categories, [&out](DiagGroupID diagGroupID) {
+        out << "\"" << getDiagGroupInfoByID(diagGroupID).name << "\"";
+      }, [&out] {
+        out << ", ";
+      });
+      out << "]";
+    }
+    if (auto version = feature.getLanguageVersion()) {
+      out << ", \"enabled_in\": \"" << *version << "\"";
+    }
+
+    if (auto flagName = optionalFlagName(feature)) {
+      out << ", \"flag_name\": \"" << *flagName << "\"";
+    }
+
+    out << " }";
+  };
+
+  out << "  \"features\": {\n";
+  out << "    \"optional\": [\n";
+  llvm::interleave(optional, printFeature, [&out] { out << ",\n"; });
+  out << "\n    ],\n";
+
+  out << "    \"upcoming\": [\n";
+  llvm::interleave(upcoming, printFeature, [&out] { out << ",\n"; });
+  out << "\n    ],\n";
+
+  out << "    \"experimental\": [\n";
+  llvm::interleave(experimental, printFeature, [&out] { out << ",\n"; });
+  out << "\n    ]\n";
+
+  out << "  }\n";
+  out << "}\n";
+}
+
+} // end namespace features
+} // end namespace swift
diff --git a/lib/Basic/TargetInfo.cpp b/lib/Basic/TargetInfo.cpp
index 53f3a219d7205..36e1512d1d103 100644
--- a/lib/Basic/TargetInfo.cpp
+++ b/lib/Basic/TargetInfo.cpp
@@ -65,6 +65,14 @@ void printTargetInfo(const CompilerInvocation &invocation,
   writeEscaped(version::getSwiftFullVersion(version::Version::getCurrentLanguageVersion()), out);
   out << "\",\n";
 
+  // Distribution tag, if any.
+  StringRef tag = version::getCurrentCompilerTag();
+  if (!tag.empty()) {
+    out << "  \"swiftCompilerTag\": \"";
+    writeEscaped(tag, out);
+    out << "\",\n";
+  }
+
   // Target triple and target variant triple.
   auto runtimeVersion =
     invocation.getIRGenOptions().AutolinkRuntimeCompatibilityLibraryVersion;
@@ -137,13 +145,13 @@ void printTripleInfo(const CompilerInvocation &invocation,
   out << "    \"arch\": \"" << swift::getMajorArchitectureName(triple)
       << "\",\n";
 
-  clang::DiagnosticsEngine DE{new clang::DiagnosticIDs(),
-                              new clang::DiagnosticOptions(),
+  clang::DiagnosticOptions diagOpts;
+  clang::DiagnosticsEngine DE{new clang::DiagnosticIDs(), diagOpts,
                               new clang::IgnoringDiagConsumer()};
-  std::shared_ptr<clang::TargetOptions> TO =
-      std::make_shared<clang::TargetOptions>();
-  TO->Triple = triple.str();
-  clang::TargetInfo *TI = clang::TargetInfo::CreateTargetInfo(DE, TO);
+
+  clang::TargetOptions targetOpts;
+  targetOpts.Triple = triple.str();
+  clang::TargetInfo *TI = clang::TargetInfo::CreateTargetInfo(DE, targetOpts);
   out << "    \"pointerWidthInBits\": "
       << TI->getPointerWidth(clang::LangAS::Default) << ",\n";
   out << "    \"pointerWidthInBytes\": "
diff --git a/lib/Basic/Version.cpp b/lib/Basic/Version.cpp
index 94085bf601654..5dfdb030278c1 100644
--- a/lib/Basic/Version.cpp
+++ b/lib/Basic/Version.cpp
@@ -181,16 +181,19 @@ std::optional<Version> Version::getEffectiveLanguageVersion() const {
     static_assert(SWIFT_VERSION_MAJOR == 6,
                   "getCurrentLanguageVersion is no longer correct here");
     return Version::getCurrentLanguageVersion();
-  case 7:
-    // Allow version '7' in asserts compilers *only* so that we can start
-    // testing changes planned for after Swift 6. Note that it's still not
-    // listed in `Version::getValidEffectiveVersions()`.
-    // FIXME: When Swift 7 becomes real, remove 'REQUIRES: swift7' from tests
-    //        using '-swift-version 7'.
+
+  // FIXME: When Swift 7 becomes real, remove 'REQUIRES: swift7' from tests
+  //        using '-swift-version 7'.
+
+  case Version::getFutureMajorLanguageVersion():
+    // Allow the future language mode version in asserts compilers *only* so
+    // that we can start testing changes planned for after the current latest
+    // language mode. Note that it'll not be listed in
+    // `Version::getValidEffectiveVersions()`.
 #ifdef NDEBUG
     LLVM_FALLTHROUGH;
 #else
-    return Version{7};
+    return Version{Version::getFutureMajorLanguageVersion()};
 #endif
   default:
     return std::nullopt;
@@ -301,17 +304,9 @@ StringRef getSwiftRevision() {
 #endif
 }
 
-bool isCurrentCompilerTagged() {
-#ifdef SWIFT_COMPILER_VERSION
-  return true;
-#else
-  return false;
-#endif
-}
-
 StringRef getCurrentCompilerTag() {
-#ifdef SWIFT_COMPILER_VERSION
-  return SWIFT_COMPILER_VERSION;
+#ifdef SWIFT_TOOLCHAIN_VERSION
+  return SWIFT_TOOLCHAIN_VERSION;
 #else
   return StringRef();
 #endif
diff --git a/lib/ClangImporter/CFTypeInfo.h b/lib/ClangImporter/CFTypeInfo.h
index e62576f5d71f0..819d9a4db853d 100644
--- a/lib/ClangImporter/CFTypeInfo.h
+++ b/lib/ClangImporter/CFTypeInfo.h
@@ -16,6 +16,7 @@
 #ifndef SWIFT_IMPORTER_CFTYPEINFO_H
 #define SWIFT_IMPORTER_CFTYPEINFO_H
 
+#include "swift/Basic/LLVM.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/StringRef.h"
 
@@ -91,20 +92,20 @@ class CFPointeeInfo {
 
   bool isRecord() const {
     assert(isValid());
-    return !Decl.isNull() && Decl.is<const clang::RecordDecl *>();
+    return !Decl.isNull() && isa<const clang::RecordDecl *>(Decl);
   }
   const clang::RecordDecl *getRecord() const {
     assert(isRecord());
-    return Decl.get<const clang::RecordDecl *>();
+    return cast<const clang::RecordDecl *>(Decl);
   }
 
   bool isTypedef() const {
     assert(isValid());
-    return !Decl.isNull() && Decl.is<const clang::TypedefNameDecl *>();
+    return !Decl.isNull() && isa<const clang::TypedefNameDecl *>(Decl);
   }
   const clang::TypedefNameDecl *getTypedef() const {
     assert(isTypedef());
-    return Decl.get<const clang::TypedefNameDecl *>();
+    return cast<const clang::TypedefNameDecl *>(Decl);
   }
 };
 }
diff --git a/include/swift/ClangImporter/CXXMethodBridging.h b/lib/ClangImporter/CXXMethodBridging.h
similarity index 99%
rename from include/swift/ClangImporter/CXXMethodBridging.h
rename to lib/ClangImporter/CXXMethodBridging.h
index 51b3cf31e462a..ff095551cb9fa 100644
--- a/include/swift/ClangImporter/CXXMethodBridging.h
+++ b/lib/ClangImporter/CXXMethodBridging.h
@@ -4,9 +4,10 @@
 #include "swift/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "llvm/ADT/StringRef.h"
-
 #include <string>
+
 namespace swift {
+
 struct CXXMethodBridging {
   enum class Kind { unknown, getter, setter, subscript };
 
@@ -165,5 +166,7 @@ struct CXXMethodBridging {
            loweredName == "get" || loweredName == "set";
   }
 };
+
 } // namespace swift
+
 #endif // SWIFT_CXXMETHODBRIDGING_H
diff --git a/lib/ClangImporter/ClangAdapter.cpp b/lib/ClangImporter/ClangAdapter.cpp
index f832a5af21f05..363425226914e 100644
--- a/lib/ClangImporter/ClangAdapter.cpp
+++ b/lib/ClangImporter/ClangAdapter.cpp
@@ -428,7 +428,7 @@ OmissionTypeName importer::getClangTypeNameForOmission(clang::ASTContext &ctx,
 
     // ARM SVE builtin types that don't have Swift equivalents.
 #define SVE_TYPE(Name, Id, ...) case clang::BuiltinType::Id:
-#include "clang/Basic/AArch64SVEACLETypes.def"
+#include "clang/Basic/AArch64ACLETypes.def"
       return OmissionTypeName();
 
     // PPC MMA builtin types that don't have Swift equivalents.
@@ -450,6 +450,11 @@ OmissionTypeName importer::getClangTypeNameForOmission(clang::ASTContext &ctx,
 #define AMDGPU_TYPE(Name, Id, ...) case clang::BuiltinType::Id:
 #include "clang/Basic/AMDGPUTypes.def"
       return OmissionTypeName();
+
+    // HLSL intangible builtin types that don't have Swift equivalents.
+#define HLSL_INTANGIBLE_TYPE(Name, Id, ...) case clang::BuiltinType::Id:
+#include "clang/Basic/HLSLIntangibleTypes.def"
+      return OmissionTypeName();
     }
   }
 
diff --git a/lib/ClangImporter/ClangClassTemplateNamePrinter.cpp b/lib/ClangImporter/ClangClassTemplateNamePrinter.cpp
index fdd51a3af2b61..f0512c4244196 100644
--- a/lib/ClangImporter/ClangClassTemplateNamePrinter.cpp
+++ b/lib/ClangImporter/ClangClassTemplateNamePrinter.cpp
@@ -14,6 +14,7 @@
 #include "ImporterImpl.h"
 #include "swift/ClangImporter/ClangImporter.h"
 #include "clang/AST/TemplateArgumentVisitor.h"
+#include "clang/AST/Type.h"
 #include "clang/AST/TypeVisitor.h"
 
 using namespace swift;
@@ -94,6 +95,18 @@ struct TemplateInstantiationNamePrinter
     return "_";
   }
 
+  std::string VisitReferenceType(const clang::ReferenceType *type) {
+    llvm::SmallString<128> storage;
+    llvm::raw_svector_ostream buffer(storage);
+    if (type->isLValueReferenceType()) {
+      buffer << "__cxxLRef<";
+    } else {
+      buffer << "__cxxRRef<";
+    }
+    buffer << Visit(type->getPointeeType().getTypePtr()) << ">";
+    return buffer.str().str();
+  }
+
   std::string VisitPointerType(const clang::PointerType *type) {
     std::string pointeeResult = Visit(type->getPointeeType().getTypePtr());
 
diff --git a/lib/ClangImporter/ClangDerivedConformances.cpp b/lib/ClangImporter/ClangDerivedConformances.cpp
index c54a3ecd1e995..3991d985ae99b 100644
--- a/lib/ClangImporter/ClangDerivedConformances.cpp
+++ b/lib/ClangImporter/ClangDerivedConformances.cpp
@@ -265,7 +265,8 @@ instantiateTemplatedOperator(ClangImporter::Implementation &impl,
       classDecl->getLocation(), clang::OverloadCandidateSet::CSK_Operator,
       clang::OverloadCandidateSet::OperatorRewriteInfo(opKind,
                                               clang::SourceLocation(), false));
-  clangSema.LookupOverloadedBinOp(candidateSet, opKind, ops, {arg, arg}, true);
+  std::array<clang::Expr *, 2> args{arg, arg};
+  clangSema.LookupOverloadedBinOp(candidateSet, opKind, ops, args, true);
 
   clang::OverloadCandidateSet::iterator best;
   switch (candidateSet.BestViableFunction(clangSema, clang::SourceLocation(),
@@ -667,6 +668,8 @@ void swift::conformToCxxOptionalIfNeeded(
   assert(decl);
   assert(clangDecl);
   ASTContext &ctx = decl->getASTContext();
+  clang::ASTContext &clangCtx = impl.getClangASTContext();
+  clang::Sema &clangSema = impl.getClangSema();
 
   if (!isStdDecl(clangDecl, {"optional"}))
     return;
@@ -689,6 +692,64 @@ void swift::conformToCxxOptionalIfNeeded(
 
   impl.addSynthesizedTypealias(decl, ctx.getIdentifier("Wrapped"), pointeeTy);
   impl.addSynthesizedProtocolAttrs(decl, {KnownProtocolKind::CxxOptional});
+
+  // `std::optional` has a C++ constructor that takes the wrapped value as a
+  // parameter. Unfortunately this constructor has templated parameter type, so
+  // it isn't directly usable from Swift. Let's explicitly instantiate a
+  // constructor with the wrapped value type, and then import it into Swift.
+
+  auto valueTypeDecl = lookupNestedClangTypeDecl(clangDecl, "value_type");
+  if (!valueTypeDecl)
+    // `std::optional` without a value_type?!
+    return;
+  auto valueType = clangCtx.getTypeDeclType(valueTypeDecl);
+
+  auto constRefValueType =
+      clangCtx.getLValueReferenceType(valueType.withConst());
+  // Create a fake variable with type of the wrapped value.
+  auto fakeValueVarDecl = clang::VarDecl::Create(
+      clangCtx, /*DC*/ clangCtx.getTranslationUnitDecl(),
+      clang::SourceLocation(), clang::SourceLocation(), /*Id*/ nullptr,
+      constRefValueType, clangCtx.getTrivialTypeSourceInfo(constRefValueType),
+      clang::StorageClass::SC_None);
+  auto fakeValueRefExpr = new (clangCtx) clang::DeclRefExpr(
+      clangCtx, fakeValueVarDecl, false,
+      constRefValueType.getNonReferenceType(), clang::ExprValueKind::VK_LValue,
+      clang::SourceLocation());
+
+  auto clangDeclTyInfo = clangCtx.getTrivialTypeSourceInfo(
+      clang::QualType(clangDecl->getTypeForDecl(), 0));
+  SmallVector<clang::Expr *, 1> constructExprArgs = {fakeValueRefExpr};
+
+  // Instantiate the templated constructor that would accept this fake variable.
+  clang::Sema::SFINAETrap trap(clangSema);
+  auto constructExprResult = clangSema.BuildCXXTypeConstructExpr(
+      clangDeclTyInfo, clangDecl->getLocation(), constructExprArgs,
+      clangDecl->getLocation(), /*ListInitialization*/ false);
+  if (!constructExprResult.isUsable() || trap.hasErrorOccurred())
+    return;
+
+  auto castExpr = dyn_cast_or_null<clang::CastExpr>(constructExprResult.get());
+  if (!castExpr)
+    return;
+
+  // The temporary bind expression will only be present for some non-trivial C++
+  // types.
+  auto bindTempExpr =
+      dyn_cast_or_null<clang::CXXBindTemporaryExpr>(castExpr->getSubExpr());
+
+  auto constructExpr = dyn_cast_or_null<clang::CXXConstructExpr>(
+      bindTempExpr ? bindTempExpr->getSubExpr() : castExpr->getSubExpr());
+  if (!constructExpr)
+    return;
+
+  auto constructorDecl = constructExpr->getConstructor();
+
+  auto importedConstructor =
+      impl.importDecl(constructorDecl, impl.CurrentVersion);
+  if (!importedConstructor)
+    return;
+  decl->addMember(importedConstructor);
 }
 
 void swift::conformToCxxSequenceIfNeeded(
diff --git a/lib/ClangImporter/ClangDiagnosticConsumer.cpp b/lib/ClangImporter/ClangDiagnosticConsumer.cpp
index d682ae6dd5dab..185165cca43b7 100644
--- a/lib/ClangImporter/ClangDiagnosticConsumer.cpp
+++ b/lib/ClangImporter/ClangDiagnosticConsumer.cpp
@@ -34,10 +34,8 @@ namespace {
 
   public:
     ClangDiagRenderer(const clang::LangOptions &langOpts,
-                      clang::DiagnosticOptions *diagOpts,
-                      decltype(callback) fn)
-       : DiagnosticNoteRenderer(langOpts, diagOpts),
-         callback(fn) {}
+                      clang::DiagnosticOptions &diagOpts, decltype(callback) fn)
+        : DiagnosticNoteRenderer(langOpts, diagOpts), callback(fn) {}
 
   private:
     /// Is this a diagnostic that doesn't do the user any good to show if it
@@ -51,7 +49,7 @@ namespace {
       if (auto *activeDiag = info.dyn_cast<const clang::Diagnostic *>())
         ID = activeDiag->getID();
       else
-        ID = info.get<const clang::StoredDiagnostic *>()->getID();
+        ID = cast<const clang::StoredDiagnostic *>(info)->getID();
       return ID == clang::diag::note_module_import_here ||
              ID == clang::diag::err_module_not_built;
     }
@@ -107,10 +105,9 @@ namespace {
 
 ClangDiagnosticConsumer::ClangDiagnosticConsumer(
     ClangImporter::Implementation &impl,
-    clang::DiagnosticOptions &clangDiagOptions,
-    bool dumpToStderr)
-  : TextDiagnosticPrinter(llvm::errs(), &clangDiagOptions),
-    ImporterImpl(impl), DumpToStderr(dumpToStderr) {}
+    clang::DiagnosticOptions &clangDiagOptions, bool dumpToStderr)
+    : TextDiagnosticPrinter(llvm::errs(), clangDiagOptions), ImporterImpl(impl),
+      DumpToStderr(dumpToStderr) {}
 
 void ClangDiagnosticConsumer::HandleDiagnostic(
     clang::DiagnosticsEngine::Level clangDiagLevel,
@@ -179,7 +176,7 @@ void ClangDiagnosticConsumer::HandleDiagnostic(
     assert(clangDiag.hasSourceManager());
     auto clangCI = ImporterImpl.getClangInstance();
     ClangDiagRenderer renderer(clangCI->getLangOpts(),
-                               &clangCI->getDiagnosticOpts(), emitDiag);
+                               clangCI->getDiagnosticOpts(), emitDiag);
     clang::FullSourceLoc clangDiagLoc(clangDiag.getLocation(),
                                       clangDiag.getSourceManager());
     renderer.emitDiagnostic(clangDiagLoc, clangDiagLevel, message,
diff --git a/lib/ClangImporter/ClangImporter.cpp b/lib/ClangImporter/ClangImporter.cpp
index ade853a2fa111..60cc7c87fbd32 100644
--- a/lib/ClangImporter/ClangImporter.cpp
+++ b/lib/ClangImporter/ClangImporter.cpp
@@ -24,6 +24,7 @@
 #include "swift/AST/Builtins.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/ConcreteDeclRef.h"
+#include "swift/AST/Decl.h"
 #include "swift/AST/DiagnosticEngine.h"
 #include "swift/AST/DiagnosticsClangImporter.h"
 #include "swift/AST/DiagnosticsSema.h"
@@ -66,6 +67,7 @@
 #include "clang/Basic/FileEntry.h"
 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/LangStandard.h"
+#include "clang/Basic/MacroBuilder.h"
 #include "clang/Basic/Module.h"
 #include "clang/Basic/Specifiers.h"
 #include "clang/Basic/TargetInfo.h"
@@ -89,6 +91,7 @@
 #include "clang/Serialization/ASTReader.h"
 #include "clang/Serialization/ASTWriter.h"
 #include "clang/Serialization/ObjectFilePCHContainerReader.h"
+#include "clang/Tooling/DependencyScanning/ModuleDepCollector.h"
 #include "clang/Tooling/DependencyScanning/ScanAndUpdateArgs.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/STLExtras.h"
@@ -326,7 +329,7 @@ class BridgingPPTracker : public clang::PPCallbacks {
       return;
     SmallVector<clang::SourceLocation, 4> IdLocs;
     for (auto &P : Path)
-      IdLocs.push_back(P.second);
+      IdLocs.push_back(P.getLoc());
     handleImport(ImportLoc, IdLocs, Imported);
   }
 
@@ -441,12 +444,10 @@ bool ClangImporter::Implementation::shouldIgnoreBridgeHeaderTopLevelDecl(
   return importer::isForwardDeclOfType(D);
 }
 
-ClangImporter::ClangImporter(ASTContext &ctx,
-                             DependencyTracker *tracker,
+ClangImporter::ClangImporter(ASTContext &ctx, DependencyTracker *tracker,
                              DWARFImporterDelegate *dwarfImporterDelegate)
     : ClangModuleLoader(tracker),
-      Impl(*new Implementation(ctx, tracker, dwarfImporterDelegate)) {
-}
+      Impl(*new Implementation(ctx, tracker, dwarfImporterDelegate)) {}
 
 ClangImporter::~ClangImporter() {
   delete &Impl;
@@ -476,6 +477,11 @@ void importer::getNormalInvocationArguments(
   if (LangOpts.ClangTarget.has_value() && !ignoreClangTarget) {
     triple = LangOpts.ClangTarget.value();
   }
+  auto canonicalTriple = getCanonicalTriple(triple);
+  if (canonicalTriple.has_value() &&
+      !areTriplesStrictlyEqual(*canonicalTriple, triple))
+    triple = *canonicalTriple;
+
   SearchPathOptions &searchPathOpts = ctx.SearchPathOpts;
   ClangImporterOptions &importerOpts = ctx.ClangImporterOpts;
   auto languageVersion = ctx.LangOpts.EffectiveLanguageVersion;
@@ -511,6 +517,10 @@ void importer::getNormalInvocationArguments(
       "-isystem", searchPathOpts.RuntimeResourcePath,
   });
 
+  if (LangOpts.hasFeature(Feature::Embedded)) {
+    invocationArgStrs.insert(invocationArgStrs.end(), {"-D__swift_embedded__"});
+  }
+
   // Enable Position Independence.  `-fPIC` is not supported on Windows, which
   // is implicitly position independent.
   if (!triple.isOSWindows())
@@ -676,6 +686,9 @@ void importer::getNormalInvocationArguments(
     }
   }
 
+  if (LangOpts.UseStaticStandardLibrary)
+    invocationArgStrs.push_back("-DSWIFT_STATIC_STDLIB");
+
   // If we support SendingArgsAndResults, set the -D flag to signal that it
   // is supported.
   if (LangOpts.hasFeature(Feature::SendingArgsAndResults))
@@ -772,6 +785,10 @@ void importer::getNormalInvocationArguments(
     invocationArgStrs.push_back("-iapinotes-modules");
     invocationArgStrs.push_back(path.str().str());
   }
+
+  if (importerOpts.LoadVersionIndependentAPINotes)
+    invocationArgStrs.insert(invocationArgStrs.end(),
+                             {"-fswift-version-independent-apinotes"});
 }
 
 static void
@@ -799,6 +816,11 @@ importer::addCommonInvocationArguments(
   if (ctx.LangOpts.ClangTarget.has_value() && !ignoreClangTarget) {
     triple = ctx.LangOpts.ClangTarget.value();
   }
+  auto canonicalTriple = getCanonicalTriple(triple);
+  if (canonicalTriple.has_value() &&
+      !areTriplesStrictlyEqual(*canonicalTriple, triple))
+    triple = *canonicalTriple;
+
   SearchPathOptions &searchPathOpts = ctx.SearchPathOpts;
   const ClangImporterOptions &importerOpts = ctx.ClangImporterOpts;
 
@@ -821,9 +843,8 @@ importer::addCommonInvocationArguments(
     switch (triple.getArch()) {
     case llvm::Triple::x86:
     case llvm::Triple::x86_64:
-      // `-mcpu` is deprecated and an alias for `-mtune`. We need to pass
-      // `-march` and `-mtune` to behave identically to the `apple-a\d+` cases
-      // below.
+      // For x86, `-mcpu` is deprecated and an alias of `-mtune`. We need to
+      // pass `-march` and `-mtune` to behave like `-mcpu` on other targets.
       invocationArgStrs.push_back("-march=" + importerOpts.TargetCPU);
       invocationArgStrs.push_back("-mtune=" + importerOpts.TargetCPU);
       break;
@@ -831,29 +852,6 @@ importer::addCommonInvocationArguments(
       invocationArgStrs.push_back("-mcpu=" + importerOpts.TargetCPU);
       break;
     }
-  } else if (triple.isOSDarwin()) {
-    // Special case CPU based on known deployments:
-    //   - arm64 deploys to apple-a7
-    //   - arm64 on macOS
-    //   - arm64 for iOS/tvOS/watchOS simulators
-    //   - arm64e deploys to apple-a12
-    // and arm64e (everywhere) and arm64e macOS defaults to the "apple-a12" CPU
-    // for Darwin, but Clang only detects this if we use -arch.
-    if (triple.getArchName() == "arm64e")
-      invocationArgStrs.push_back("-mcpu=apple-a12");
-    else if (triple.isAArch64() && triple.isMacOSX())
-      invocationArgStrs.push_back("-mcpu=apple-a12");
-    else if (triple.isAArch64() && triple.isSimulatorEnvironment() &&
-             (triple.isiOS() || triple.isWatchOS()))
-      invocationArgStrs.push_back("-mcpu=apple-a12");
-    else if (triple.isAArch64() && triple.isSimulatorEnvironment() &&
-             triple.isXROS())
-      invocationArgStrs.push_back("-mcpu=apple-a12");
-    else if (triple.getArch() == llvm::Triple::aarch64 ||
-             triple.getArch() == llvm::Triple::aarch64_32 ||
-             triple.getArch() == llvm::Triple::aarch64_be) {
-      invocationArgStrs.push_back("-mcpu=apple-a7");
-    }
   } else if (triple.getArch() == llvm::Triple::systemz) {
     invocationArgStrs.push_back("-march=z13");
   }
@@ -864,6 +862,10 @@ importer::addCommonInvocationArguments(
     invocationArgStrs.push_back("-mcx16");
   }
 
+  // REPL and LLDB unconditionally want debug info in pcm files.
+  if (importerOpts.DebuggerSupport)
+    invocationArgStrs.push_back("-g");
+
   if (triple.isOSDarwin()) {
     if (auto variantTriple = ctx.LangOpts.TargetVariant) {
       // Passing the -target-variant along to clang causes clang's
@@ -871,6 +873,12 @@ importer::addCommonInvocationArguments(
       invocationArgStrs.push_back("-darwin-target-variant");
       if (ctx.LangOpts.ClangTargetVariant.has_value() && !ignoreClangTarget)
         variantTriple = ctx.LangOpts.ClangTargetVariant.value();
+
+      auto canonicalVariantTriple = getCanonicalTriple(*variantTriple);
+      if (canonicalVariantTriple.has_value() &&
+          !areTriplesStrictlyEqual(*canonicalVariantTriple, *variantTriple))
+        *variantTriple = *canonicalVariantTriple;
+
       invocationArgStrs.push_back(variantTriple->str());
     }
 
@@ -981,10 +989,8 @@ bool ClangImporter::canReadPCH(StringRef PCHFilename) {
   // FIXME: The following attempts to do an initial ReadAST invocation to verify
   // the PCH, without causing trouble for the existing CompilerInstance.
   // Look into combining creating the ASTReader along with verification + update
-  // if necessary, so that we can create and use one ASTReader in the common case
-  // when there is no need for update.
-  clang::CompilerInstance CI(Impl.Instance->getPCHContainerOperations(),
-                             &Impl.Instance->getModuleCache());
+  // if necessary, so that we can create and use one ASTReader in the common
+  // case when there is no need for update.
   auto invocation =
       std::make_shared<clang::CompilerInvocation>(*Impl.Invocation);
   invocation->getPreprocessorOpts().DisablePCHOrModuleValidation =
@@ -999,10 +1005,13 @@ bool ClangImporter::canReadPCH(StringRef PCHFilename) {
   // will try to free it.
   invocation->getPreprocessorOpts().RemappedFileBuffers.clear();
 
-  CI.setInvocation(std::move(invocation));
+  clang::DiagnosticOptions diagOpts;
+  clang::CompilerInstance CI(std::move(invocation),
+                             Impl.Instance->getPCHContainerOperations(),
+                             &Impl.Instance->getModuleCache());
   CI.setTarget(&Impl.Instance->getTarget());
-  CI.setDiagnostics(
-      &*clang::CompilerInstance::createDiagnostics(new clang::DiagnosticOptions()));
+  CI.setDiagnostics(&*clang::CompilerInstance::createDiagnostics(
+      Impl.Instance->getVirtualFileSystem(), diagOpts));
 
   // Note: Reusing the file manager is safe; this is a component that's already
   // reused when building PCM files for the module cache.
@@ -1061,27 +1070,6 @@ std::string ClangImporter::getOriginalSourceFile(StringRef PCHFilename) {
       Impl.Instance->getPCHContainerReader(), Impl.Instance->getDiagnostics());
 }
 
-void ClangImporter::addClangInvovcationDependencies(
-    std::vector<std::string> &files) {
-  auto addFiles = [&files](const auto &F) {
-    files.insert(files.end(), F.begin(), F.end());
-  };
-  auto &invocation = *Impl.Invocation;
-  // FIXME: Add file dependencies that are not accounted. The long term solution
-  // is to do a dependency scanning for clang importer and use that directly.
-  SmallVector<std::string, 4> HeaderMapFileNames;
-  Impl.Instance->getPreprocessor().getHeaderSearchInfo().getHeaderMapFileNames(
-      HeaderMapFileNames);
-  addFiles(HeaderMapFileNames);
-  addFiles(invocation.getHeaderSearchOpts().VFSOverlayFiles);
-  // FIXME: Should not depend on working directory. Build system/swift driver
-  // should not pass working directory here but if that option is passed,
-  // repect that and add that into CASFS.
-  auto CWD = invocation.getFileSystemOpts().WorkingDir;
-  if (!CWD.empty())
-    files.push_back(CWD);
-}
-
 std::optional<std::string>
 ClangImporter::getPCHFilename(const ClangImporterOptions &ImporterOptions,
                               StringRef SwiftPCHHash, bool &isExplicit) {
@@ -1163,6 +1151,8 @@ ClangImporter::getClangDriverArguments(ASTContext &ctx, bool ignoreClangTarget)
 std::optional<std::vector<std::string>> ClangImporter::getClangCC1Arguments(
     ASTContext &ctx, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
     bool ignoreClangTarget) {
+  ASSERT(VFS && "Expected non-null file system");
+
   std::unique_ptr<clang::CompilerInvocation> CI;
 
   // Set up a temporary diagnostic client to report errors from parsing the
@@ -1173,13 +1163,11 @@ std::optional<std::vector<std::string>> ClangImporter::getClangCC1Arguments(
   //
   // The long-term client for Clang diagnostics is set up afterwards, after the
   // clang::CompilerInstance is created.
-  llvm::IntrusiveRefCntPtr<clang::DiagnosticOptions> tempDiagOpts{
-      new clang::DiagnosticOptions};
-  auto *tempDiagClient =
-      new ClangDiagnosticConsumer(Impl, *tempDiagOpts,
-                                  ctx.ClangImporterOpts.DumpClangDiagnostics);
+  clang::DiagnosticOptions tempDiagOpts;
+  auto *tempDiagClient = new ClangDiagnosticConsumer(
+      Impl, tempDiagOpts, ctx.ClangImporterOpts.DumpClangDiagnostics);
   auto clangDiags = clang::CompilerInstance::createDiagnostics(
-      tempDiagOpts.get(), tempDiagClient,
+      *VFS, tempDiagOpts, tempDiagClient,
       /*owned*/ true);
 
   // If using direct cc1 module build, use extra args to setup ClangImporter.
@@ -1200,7 +1188,7 @@ std::optional<std::vector<std::string>> ClangImporter::getClangCC1Arguments(
     // to reduce the number of argument passing on the command-line and swift
     // compiler can be more efficient to compute swift cache key without having
     // the knowledge about clang command-line options.
-    if (ctx.CASOpts.EnableCaching) {
+    if (ctx.CASOpts.EnableCaching || ctx.CASOpts.ImportModuleFromCAS) {
       CI->getCASOpts() = ctx.CASOpts.CASOpts;
       // When clangImporter is used to compile (generate .pcm or .pch), need to
       // inherit the include tree from swift args (last one wins) and clear the
@@ -1209,9 +1197,8 @@ std::optional<std::vector<std::string>> ClangImporter::getClangCC1Arguments(
                clang::frontend::ActionKind::GenerateModule ||
            CI->getFrontendOpts().ProgramAction ==
                clang::frontend::ActionKind::GeneratePCH) &&
-          ctx.ClangImporterOpts.HasClangIncludeTreeRoot) {
-        CI->getFrontendOpts().CASIncludeTreeID =
-            ctx.CASOpts.ClangIncludeTrees.back();
+          !ctx.CASOpts.ClangIncludeTree.empty()) {
+        CI->getFrontendOpts().CASIncludeTreeID = ctx.CASOpts.ClangIncludeTree;
         CI->getFrontendOpts().Inputs.clear();
       }
     }
@@ -1264,13 +1251,11 @@ std::optional<std::vector<std::string>> ClangImporter::getClangCC1Arguments(
   // to missing files and report the error that clang would throw manually.
   // rdar://77516546 is tracking that the clang importer should be more
   // resilient and provide a module even if there were building it.
-  auto TempVFS = clang::createVFSFromCompilerInvocation(
-      *CI, *clangDiags,
-      VFS ? VFS : Impl.SwiftContext.SourceMgr.getFileSystem());
+  auto TempVFS = clang::createVFSFromCompilerInvocation(*CI, *clangDiags, VFS);
 
   std::vector<std::string> FilteredModuleMapFiles;
   for (auto ModuleMapFile : CI->getFrontendOpts().ModuleMapFiles) {
-    if (ctx.ClangImporterOpts.HasClangIncludeTreeRoot) {
+    if (ctx.CASOpts.HasImmutableFileSystem) {
       // There is no need to add any module map file here. Issue a warning and
       // drop the option.
       Impl.diagnose(SourceLoc(), diag::module_map_ignored, ModuleMapFile);
@@ -1302,10 +1287,10 @@ std::unique_ptr<clang::CompilerInvocation> ClangImporter::createClangInvocation(
   // option here is either generated by dependency scanner or just round tripped
   // from `getClangCC1Arguments` so we don't expect it to fail. Use a simple
   // printing diagnostics consumer for debugging any unexpected error.
-  auto diagOpts = llvm::makeIntrusiveRefCnt<clang::DiagnosticOptions>();
+  clang::DiagnosticOptions diagOpts;
   clang::DiagnosticsEngine clangDiags(
       new clang::DiagnosticIDs(), diagOpts,
-      new clang::TextDiagnosticPrinter(llvm::errs(), diagOpts.get()));
+      new clang::TextDiagnosticPrinter(llvm::errs(), diagOpts));
 
   // Finally, use the CC1 command-line and the diagnostic engine
   // to instantiate our Invocation.
@@ -1317,11 +1302,9 @@ std::unique_ptr<clang::CompilerInvocation> ClangImporter::createClangInvocation(
   return CI;
 }
 
-std::unique_ptr<ClangImporter>
-ClangImporter::create(ASTContext &ctx,
-                      std::string swiftPCHHash, DependencyTracker *tracker,
-                      DWARFImporterDelegate *dwarfImporterDelegate,
-                      bool ignoreFileMapping) {
+std::unique_ptr<ClangImporter> ClangImporter::create(
+    ASTContext &ctx, std::string swiftPCHHash, DependencyTracker *tracker,
+    DWARFImporterDelegate *dwarfImporterDelegate, bool ignoreFileMapping) {
   std::unique_ptr<ClangImporter> importer{
       new ClangImporter(ctx, tracker, dwarfImporterDelegate)};
   auto &importerOpts = ctx.ClangImporterOpts;
@@ -1344,49 +1327,11 @@ ClangImporter::create(ASTContext &ctx,
       ctx.SourceMgr.getFileSystem();
 
   ClangInvocationFileMapping fileMapping =
-    getClangInvocationFileMapping(ctx, nullptr, ignoreFileMapping);
+    applyClangInvocationMapping(ctx, nullptr, VFS, ignoreFileMapping);
 
   importer->requiresBuiltinHeadersInSystemModules =
       fileMapping.requiresBuiltinHeadersInSystemModules;
 
-  // Avoid creating indirect file system when using include tree.
-  if (!ctx.ClangImporterOpts.HasClangIncludeTreeRoot) {
-    // Wrap Swift's FS to allow Clang to override the working directory
-    VFS = llvm::vfs::RedirectingFileSystem::create(
-        fileMapping.redirectedFiles, true, *ctx.SourceMgr.getFileSystem());
-    if (importerOpts.DumpClangDiagnostics) {
-      llvm::errs() << "clang importer redirected file mappings:\n";
-      for (const auto &mapping : fileMapping.redirectedFiles) {
-        llvm::errs() << "   mapping real file '" << mapping.second
-                     << "' to virtual file '" << mapping.first << "'\n";
-      }
-      llvm::errs() << "\n";
-    }
-
-    if (!fileMapping.overridenFiles.empty()) {
-      llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> overridenVFS =
-          new llvm::vfs::InMemoryFileSystem();
-      for (const auto &file : fileMapping.overridenFiles) {
-        if (importerOpts.DumpClangDiagnostics) {
-          llvm::errs() << "clang importer overriding file '" << file.first
-                       << "' with the following contents:\n";
-          llvm::errs() << file.second << "\n";
-        }
-        auto contents = ctx.Allocate<char>(file.second.size() + 1);
-        std::copy(file.second.begin(), file.second.end(), contents.begin());
-        // null terminate the buffer.
-        contents[contents.size() - 1] = '\0';
-        overridenVFS->addFile(file.first, 0,
-                              llvm::MemoryBuffer::getMemBuffer(StringRef(
-                                  contents.begin(), contents.size() - 1)));
-      }
-      llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> overlayVFS =
-          new llvm::vfs::OverlayFileSystem(VFS);
-      VFS = overlayVFS;
-      overlayVFS->pushOverlay(overridenVFS);
-    }
-  }
-
   // Create a new Clang compiler invocation.
   {
     if (auto ClangArgs = importer->getClangCC1Arguments(ctx, VFS))
@@ -1432,6 +1377,9 @@ ClangImporter::create(ASTContext &ctx,
     // The Clang modules produced by ClangImporter are always embedded in an
     // ObjectFilePCHContainer and contain -gmodules debug info.
     importer->Impl.Invocation->getCodeGenOpts().DebugTypeExtRefs = true;
+    if (importerOpts.DebuggerSupport)
+      importer->Impl.Invocation->getCodeGenOpts().setDebugInfo(
+          llvm::codegenoptions::FullDebugInfo);
 
     auto PCHContainerOperations =
       std::make_shared<clang::PCHContainerOperations>();
@@ -1439,12 +1387,10 @@ ClangImporter::create(ASTContext &ctx,
         std::make_unique<clang::ObjectFilePCHContainerWriter>());
     PCHContainerOperations->registerReader(
         std::make_unique<clang::ObjectFilePCHContainerReader>());
-    importer->Impl.Instance.reset(
-        new clang::CompilerInstance(std::move(PCHContainerOperations)));
+    importer->Impl.Instance.reset(new clang::CompilerInstance(
+        importer->Impl.Invocation, std::move(PCHContainerOperations)));
   }
   auto &instance = *importer->Impl.Instance;
-  instance.setInvocation(importer->Impl.Invocation);
-
   if (tracker)
     instance.addDependencyCollector(tracker->getClangCollector());
 
@@ -1454,7 +1400,7 @@ ClangImporter::create(ASTContext &ctx,
     auto actualDiagClient = std::make_unique<ClangDiagnosticConsumer>(
         importer->Impl, instance.getDiagnosticOpts(),
         importerOpts.DumpClangDiagnostics);
-    instance.createDiagnostics(actualDiagClient.release());
+    instance.createDiagnostics(*VFS, actualDiagClient.release());
   }
 
   // Set up the file manager.
@@ -1488,16 +1434,12 @@ ClangImporter::create(ASTContext &ctx,
         importer.get(), importerOpts, VFS, *swiftTargetClangArgs);
     if (!swiftTargetClangInvocation)
       return nullptr;
-    importer->Impl.setSwiftTargetInfo(clang::TargetInfo::CreateTargetInfo(
-        clangDiags, swiftTargetClangInvocation->TargetOpts));
-    importer->Impl.setSwiftCodeGenOptions(new clang::CodeGenOptions(
-        swiftTargetClangInvocation->getCodeGenOpts()));
+
+    importer->Impl.configureOptionsForCodeGen(clangDiags,
+                                              swiftTargetClangInvocation.get());
   } else {
-    // Just use the existing Invocation's directly
-    importer->Impl.setSwiftTargetInfo(clang::TargetInfo::CreateTargetInfo(
-        clangDiags, importer->Impl.Invocation->TargetOpts));
-    importer->Impl.setSwiftCodeGenOptions(
-        new clang::CodeGenOptions(importer->Impl.Invocation->getCodeGenOpts()));
+    // Set using the existing invocation.
+    importer->Impl.configureOptionsForCodeGen(clangDiags);
   }
 
   // Create the associated action.
@@ -1514,9 +1456,8 @@ ClangImporter::create(ASTContext &ctx,
   // things here.
 
   // Create the target instance.
-  instance.setTarget(
-    clang::TargetInfo::CreateTargetInfo(clangDiags,
-                                        instance.getInvocation().TargetOpts));
+  instance.setTarget(clang::TargetInfo::CreateTargetInfo(
+      clangDiags, instance.getInvocation().getTargetOpts()));
   if (!instance.hasTarget())
     return nullptr;
 
@@ -1524,7 +1465,8 @@ ClangImporter::create(ASTContext &ctx,
   //
   // FIXME: We shouldn't need to do this, the target should be immutable once
   // created. This complexity should be lifted elsewhere.
-  instance.getTarget().adjust(clangDiags, instance.getLangOpts());
+  instance.getTarget().adjust(clangDiags, instance.getLangOpts(),
+                              /*AuxTarget=*/nullptr);
 
   if (importerOpts.Mode == ClangImporterOptions::Modes::EmbedBitcode)
     return importer;
@@ -1839,15 +1781,24 @@ bool ClangImporter::importHeader(StringRef header, ModuleDecl *adapter,
                                  off_t expectedSize, time_t expectedModTime,
                                  StringRef cachedContents, SourceLoc diagLoc) {
   clang::FileManager &fileManager = Impl.Instance->getFileManager();
-  auto headerFile = fileManager.getFile(header, /*OpenFile=*/true);
-  // Prefer importing the header directly if the header content matches by
-  // checking size and mod time. This allows correct import if some no-modular
-  // headers are already imported into clang importer. If mod time is zero, then
-  // the module should be built from CAS and there is no mod time to verify.
-  if (headerFile && (*headerFile)->getSize() == expectedSize &&
-      (expectedModTime == 0 ||
-       (*headerFile)->getModificationTime() == expectedModTime)) {
-    return importBridgingHeader(header, adapter, diagLoc, false, true);
+  // Especially in an explicit modules project, LLDB might not know all the
+  // search paths needed to imported the on disk header, so prefer the
+  // serialized preprocessed contents when debugger support is on.
+  if (!Impl.SwiftContext.ClangImporterOpts.PreferSerializedBridgingHeader ||
+      cachedContents.empty()) {
+    auto headerFile = fileManager.getOptionalFileRef(header, /*OpenFile=*/true);
+    // Prefer importing the header directly if the header content matches by
+    // checking size and mod time. This allows correct import if some no-modular
+    // headers are already imported into clang importer. If mod time is zero,
+    // then the module should be built from CAS and there is no mod time to
+    // verify.  LLDB prefers the serialized bridging header because, in an
+    // explicit modules project, LLDB might not know all the search paths needed
+    // to imported the on disk header.
+    if (headerFile && headerFile->getSize() == expectedSize &&
+        (expectedModTime == 0 ||
+         headerFile->getModificationTime() == expectedModTime)) {
+      return importBridgingHeader(header, adapter, diagLoc, false, true);
+    }
   }
 
   // If we've made it to here, this is some header other than the bridging
@@ -1857,9 +1808,8 @@ bool ClangImporter::importHeader(StringRef header, ModuleDecl *adapter,
 
   if (!cachedContents.empty() && cachedContents.back() == '\0')
     cachedContents = cachedContents.drop_back();
-  std::unique_ptr<llvm::MemoryBuffer> sourceBuffer{
-    llvm::MemoryBuffer::getMemBuffer(cachedContents, header)
-  };
+  std::unique_ptr<llvm::MemoryBuffer> sourceBuffer =
+      llvm::MemoryBuffer::getMemBufferCopy(cachedContents, header);
   return Impl.importHeader(adapter, header, diagLoc, /*trackParsedSymbols=*/false,
                            std::move(sourceBuffer), true);
 }
@@ -1869,16 +1819,11 @@ bool ClangImporter::importBridgingHeader(StringRef header, ModuleDecl *adapter,
                                          bool trackParsedSymbols,
                                          bool implicitImport) {
   if (isPCHFilenameExtension(header)) {
-    Impl.ImportedHeaderOwners.push_back(adapter);
-    // We already imported this with -include-pch above, so we should have
-    // collected a bunch of PCH-encoded module imports that we just need to
-    // replay in handleDeferredImports.
-    Impl.handleDeferredImports(diagLoc);
-    return false;
+    return bindBridgingHeader(adapter, diagLoc);
   }
 
   clang::FileManager &fileManager = Impl.Instance->getFileManager();
-  auto headerFile = fileManager.getFile(header, /*OpenFile=*/true);
+  auto headerFile = fileManager.getOptionalFileRef(header, /*OpenFile=*/true);
   if (!headerFile) {
     Impl.diagnose(diagLoc, diag::bridging_header_missing, header);
     return true;
@@ -1901,6 +1846,15 @@ bool ClangImporter::importBridgingHeader(StringRef header, ModuleDecl *adapter,
                            std::move(sourceBuffer), implicitImport);
 }
 
+bool ClangImporter::bindBridgingHeader(ModuleDecl *adapter, SourceLoc diagLoc) {
+  Impl.ImportedHeaderOwners.push_back(adapter);
+  // We already imported this with -include-pch above, so we should have
+  // collected a bunch of PCH-encoded module imports that we just need to
+  // replay in handleDeferredImports.
+  Impl.handleDeferredImports(diagLoc);
+  return false;
+}
+
 static llvm::Expected<llvm::cas::ObjectRef>
 setupIncludeTreeInput(clang::CompilerInvocation &invocation,
                       StringRef headerPath, StringRef pchIncludeTree) {
@@ -1962,13 +1916,13 @@ std::string ClangImporter::getBridgingHeaderContents(
 
   invocation->getPreprocessorOpts().resetNonModularOptions();
 
-  clang::CompilerInstance rewriteInstance(
-    Impl.Instance->getPCHContainerOperations(),
-    &Impl.Instance->getModuleCache());
-  rewriteInstance.setInvocation(invocation);
-  rewriteInstance.createDiagnostics(new clang::IgnoringDiagConsumer);
-
   clang::FileManager &fileManager = Impl.Instance->getFileManager();
+
+  clang::CompilerInstance rewriteInstance(
+      std::move(invocation), Impl.Instance->getPCHContainerOperations(),
+      &Impl.Instance->getModuleCache());
+  rewriteInstance.createDiagnostics(fileManager.getVirtualFileSystem(),
+                                    new clang::IgnoringDiagConsumer);
   rewriteInstance.setFileManager(&fileManager);
   rewriteInstance.createSourceManager(fileManager);
   rewriteInstance.setTarget(&Impl.Instance->getTarget());
@@ -2018,9 +1972,9 @@ std::string ClangImporter::getBridgingHeaderContents(
     return "";
   }
 
-  if (auto fileInfo = fileManager.getFile(headerPath)) {
-    fileSize = (*fileInfo)->getSize();
-    fileModTime = (*fileInfo)->getModificationTime();
+  if (auto fileInfo = fileManager.getOptionalFileRef(headerPath)) {
+    fileSize = fileInfo->getSize();
+    fileModTime = fileInfo->getModificationTime();
   }
   return result;
 }
@@ -2067,14 +2021,14 @@ ClangImporter::cloneCompilerInstanceForPrecompiling() {
   // Share the CASOption and the underlying CAS.
   invocation->setCASOption(Impl.Invocation->getCASOptsPtr());
 
+  clang::FileManager &fileManager = Impl.Instance->getFileManager();
+
   auto clonedInstance = std::make_unique<clang::CompilerInstance>(
-    Impl.Instance->getPCHContainerOperations(),
-    &Impl.Instance->getModuleCache());
-  clonedInstance->setInvocation(std::move(invocation));
-  clonedInstance->createDiagnostics(&Impl.Instance->getDiagnosticClient(),
+      std::move(invocation), Impl.Instance->getPCHContainerOperations(),
+      &Impl.Instance->getModuleCache());
+  clonedInstance->createDiagnostics(fileManager.getVirtualFileSystem(),
+                                    &Impl.Instance->getDiagnosticClient(),
                                     /*ShouldOwnClient=*/false);
-
-  clang::FileManager &fileManager = Impl.Instance->getFileManager();
   clonedInstance->setFileManager(&fileManager);
   clonedInstance->createSourceManager(fileManager);
   clonedInstance->setTarget(&Impl.Instance->getTarget());
@@ -2360,17 +2314,15 @@ ModuleDecl *ClangImporter::Implementation::loadModuleClang(
   auto realModuleName = SwiftContext.getRealModuleName(path.front().Item).str();
 
   // Convert the Swift import path over to a Clang import path.
-  SmallVector<std::pair<clang::IdentifierInfo *, clang::SourceLocation>, 4>
-      clangPath;
+  SmallVector<clang::IdentifierLoc, 4> clangPath;
   bool isTopModuleComponent = true;
   for (auto component : path) {
     StringRef item = isTopModuleComponent? realModuleName:
                                            component.Item.str();
     isTopModuleComponent = false;
 
-    clangPath.emplace_back(
-        getClangPreprocessor().getIdentifierInfo(item),
-        exportSourceLoc(component.Loc));
+    clangPath.emplace_back(exportSourceLoc(component.Loc),
+                           getClangPreprocessor().getIdentifierInfo(item));
   }
 
   auto &diagEngine = Instance->getDiagnostics();
@@ -2380,14 +2332,13 @@ ModuleDecl *ClangImporter::Implementation::loadModuleClang(
   auto loadModule = [&](clang::ModuleIdPath path,
                         clang::Module::NameVisibilityKind visibility)
       -> clang::ModuleLoadResult {
-    auto importRAII =
-        diagClient.handleImport(clangPath.front().first, diagEngine,
-                                importLoc);
+    auto importRAII = diagClient.handleImport(
+        clangPath.front().getIdentifierInfo(), diagEngine, importLoc);
 
     std::string preservedIndexStorePathOption;
     auto &clangFEOpts = Instance->getFrontendOpts();
     if (!clangFEOpts.IndexStorePath.empty()) {
-      StringRef moduleName = path[0].first->getName();
+      StringRef moduleName = path[0].getIdentifierInfo()->getName();
       // Ignore the SwiftShims module for the index data.
       if (moduleName == SwiftContext.SwiftShimsModuleName.str()) {
         preservedIndexStorePathOption = clangFEOpts.IndexStorePath;
@@ -2605,6 +2556,10 @@ PlatformAvailability::PlatformAvailability(const LangOptions &langOpts)
   case PlatformKind::visionOSApplicationExtension:
     break;
 
+  case PlatformKind::FreeBSD:
+    deprecatedAsUnavailableMessage = "";
+    break;
+
   case PlatformKind::OpenBSD:
     deprecatedAsUnavailableMessage = "";
     break;
@@ -2652,6 +2607,9 @@ bool PlatformAvailability::isPlatformRelevant(StringRef name) const {
     return name == "xros" || name == "xros_app_extension" ||
            name == "visionos" || name == "visionos_app_extension";
 
+  case PlatformKind::FreeBSD:
+    return name == "freebsd";
+
   case PlatformKind::OpenBSD:
     return name == "openbsd";
 
@@ -2723,6 +2681,10 @@ bool PlatformAvailability::treatDeprecatedAsUnavailable(
     // No deprecation filter on xrOS
     return false;
 
+  case PlatformKind::FreeBSD:
+    // No deprecation filter on FreeBSD
+    return false;
+
   case PlatformKind::OpenBSD:
     // No deprecation filter on OpenBSD
     return false;
@@ -2743,11 +2705,9 @@ ClangImporter::Implementation::Implementation(
       DisableSwiftBridgeAttr(ctx.ClangImporterOpts.DisableSwiftBridgeAttr),
       BridgingHeaderExplicitlyRequested(
           !ctx.ClangImporterOpts.BridgingHeader.empty()),
+      BridgingHeaderIsInternal(ctx.ClangImporterOpts.BridgingHeaderIsInternal),
       DisableOverlayModules(ctx.ClangImporterOpts.DisableOverlayModules),
       EnableClangSPI(ctx.ClangImporterOpts.EnableClangSPI),
-      UseClangIncludeTree(ctx.ClangImporterOpts.UseClangIncludeTree),
-      importSymbolicCXXDecls(
-          ctx.LangOpts.hasFeature(Feature::ImportSymbolicCXXDecls)),
       IsReadingBridgingPCH(false),
       CurrentVersion(ImportNameVersion::fromOptions(ctx.LangOpts)),
       Walker(DiagnosticWalker(*this)), BuffersForDiagnostics(ctx.SourceMgr),
@@ -2866,6 +2826,74 @@ ClangModuleUnit *ClangImporter::Implementation::getWrapperForModule(
   if (auto mainModule = SwiftContext.MainModule) {
     implicitImportInfo = mainModule->getImplicitImportInfo();
   }
+
+  if (!underlying->isSubModule()) {
+    // Make sure that synthesized Swift code in the clang module wrapper
+    // (e.g. _SwiftifyImport macro expansions) can access the same symbols
+    // as if it were actually in the clang module, by copying the imports.
+    // Because this top-level module wrapper contains all the imported decls
+    // of the clang submodules, we need to add the imports of all the
+    // transitive submodules, since we don't know at this point of the
+    // compilation which submodules will contain relevant macros.
+    // We also need to add (transitive) explicit submodules as imports,
+    // to make sure that they are marked as imported *somewhere* (clang modules
+    // including them don't count) - otherwise their decls won't be found after
+    // non-visible clang decls are filtered out.
+    llvm::SmallVector<const clang::Module *, 32> SubmoduleWorklist;
+    llvm::DenseSet<ImportPath> Imported;
+    SubmoduleWorklist.push_back(underlying);
+    ImportPath::Builder underlyingSwiftModulePath =
+        getSwiftModulePath(underlying);
+    Imported.insert(underlyingSwiftModulePath.get());
+    for (auto UI : implicitImportInfo.AdditionalUnloadedImports)
+      Imported.insert(UI.module.getImportPath());
+    assert(implicitImportInfo.AdditionalImports.empty());
+
+    auto addImplicitImport = [&implicitImportInfo, &Imported,
+                              this](const clang::Module *M,
+                                    bool guaranteedUnique) {
+      ImportPath::Builder builder = getSwiftModulePath(M);
+      if (!guaranteedUnique && Imported.count(builder.get()))
+        return;
+
+      // Don't perform this clone for modules already added to the list
+      ImportPath importedModulePath = builder.copyTo(SwiftContext);
+
+#ifndef NDEBUG
+      const bool performSanityCheck = true;
+#else
+      const bool performSanityCheck = false;
+#endif
+      if (!guaranteedUnique || performSanityCheck) {
+        bool WasInserted = Imported.insert(importedModulePath).second;
+        assert(WasInserted);
+      }
+
+      UnloadedImportedModule importedModule(importedModulePath,
+                                            ImportKind::Module);
+      implicitImportInfo.AdditionalUnloadedImports.push_back(
+          std::move(importedModule));
+    };
+
+    while (!SubmoduleWorklist.empty()) {
+      const clang::Module *CurrModule = SubmoduleWorklist.pop_back_val();
+      if (CurrModule->IsExplicit) {
+        // We don't add imports under the same TLM, and submodules form
+        // a tree, so these don't require deduplication.
+        addImplicitImport(CurrModule, /*guaranteedUnique=*/true);
+      }
+      for (auto *I : CurrModule->Imports) {
+        // `underlying` is the current TLM. Only explicit submodules need to
+        // be imported under the same TLM, which is handled above.
+        if (I->getTopLevelModule() == underlying)
+          continue;
+        addImplicitImport(I, /*guaranteedUnique=*/false);
+      }
+      for (auto *Submodule : CurrModule->submodules())
+        SubmoduleWorklist.push_back(Submodule);
+    }
+  }
+
   ClangModuleUnit *file = nullptr;
   auto wrapper = ModuleDecl::create(name, SwiftContext, implicitImportInfo,
                                     [&](ModuleDecl *wrapper, auto addFile) {
@@ -3405,7 +3433,7 @@ class DarwinLegacyFilterDeclConsumer : public swift::VisibleDeclConsumer {
 /// Translate a MacroDefinition to a ClangNode, either a ModuleMacro for
 /// a definition imported from a module or a MacroInfo for a macro defined
 /// locally.
-ClangNode getClangNodeForMacroDefinition(clang::MacroDefinition &M) {
+static ClangNode getClangNodeForMacroDefinition(clang::MacroDefinition &M) {
   if (!M.getModuleMacros().empty())
     return ClangNode(M.getModuleMacros().back()->getMacroInfo());
   if (auto *MD = M.getLocalDirective())
@@ -3417,7 +3445,7 @@ void ClangImporter::lookupBridgingHeaderDecls(
                               llvm::function_ref<bool(ClangNode)> filter,
                               llvm::function_ref<void(Decl*)> receiver) const {
   for (auto &Import : Impl.BridgeHeaderTopLevelImports) {
-    auto ImportD = Import.get<ImportDecl*>();
+    auto ImportD = cast<ImportDecl *>(Import);
     if (filter(ImportD->getClangDecl()))
       receiver(ImportD);
   }
@@ -3591,6 +3619,17 @@ void ClangImporter::lookupTypeDecl(
         if (auto ext = dyn_cast_or_null<ExtensionDecl>(imported)) {
           imported = ext->getExtendedNominal();
         }
+
+        // Look through compatibility aliases since we must have mangled the
+        // underlying type (see ASTMangler::getSpecialManglingContext).
+        if (auto *alias = dyn_cast_or_null<TypeAliasDecl>(imported)) {
+          if (alias->isCompatibilityAlias()) {
+            imported = alias->getUnderlyingType()->getAnyNominal();
+            assert(imported != nullptr &&
+                   "No underlying decl for a compatibility typealias");
+          }
+        }
+
         if (auto *importedType = dyn_cast_or_null<TypeDecl>(imported)) {
           foundViaClang = true;
           receiver(importedType);
@@ -3716,7 +3755,7 @@ void ClangModuleUnit::getTopLevelDecls(SmallVectorImpl<Decl*> &results) const {
 
     llvm::SmallPtrSet<ExtensionDecl *, 8> knownExtensions;
     for (auto entry : lookupTable->allGlobalsAsMembers()) {
-      auto decl = entry.get<clang::NamedDecl *>();
+      auto decl = cast<clang::NamedDecl *>(entry);
       if (decl->getOwningModule() != clangModule) continue;
 
       Decl *importedDecl = owner.importDecl(decl, owner.CurrentVersion);
@@ -3763,7 +3802,11 @@ ImportDecl *swift::createImportDecl(ASTContext &Ctx,
   while (TmpMod) {
     // If this is a C++ stdlib module, print its name as `CxxStdlib` instead of
     // `std`. `CxxStdlib` is the only accepted spelling of the C++ stdlib module
-    // name in Swift.
+    // name in Swift. In libc++ versions 17-19 there are multiple TLMs, named
+    // std_vector, std_array etc. We don't support importing those modules, but
+    // when printing the module interface it'd be weird to print "import
+    // CxxStdlib" over and over, so those are still printed as "import
+    // std_vector". This only affects the module interface for CxxStdlib.
     Identifier moduleName = !TmpMod->isSubModule() && TmpMod->Name == "std"
                                 ? Ctx.Id_CxxStdlib
                                 : Ctx.getIdentifier(TmpMod->Name);
@@ -3783,8 +3826,13 @@ ImportDecl *swift::createImportDecl(ASTContext &Ctx,
   auto *ID = ImportDecl::create(Ctx, DC, SourceLoc(),
                                 ImportKind::Module, SourceLoc(),
                                 importPath.get(), ClangN);
-  if (IsExported)
+  if (Ctx.ClangImporterOpts.BridgingHeaderIsInternal) {
+    ID->getAttrs().add(
+        new (Ctx) AccessControlAttr(SourceLoc(), SourceRange(),
+                                    AccessLevel::Internal, /*implicit=*/true));
+  } else if (IsExported) {
     ID->getAttrs().add(new (Ctx) ExportedAttr(/*IsImplicit=*/false));
+  }
   return ID;
 }
 
@@ -4114,35 +4162,30 @@ void ClangModuleUnit::lookupObjCMethods(
 
 void ClangModuleUnit::lookupAvailabilityDomains(
     Identifier identifier, SmallVectorImpl<AvailabilityDomain> &results) const {
-  auto lookupTable = owner.findLookupTable(clangModule);
-  if (!lookupTable)
+  auto domainName = identifier.str();
+  auto &ctx = getASTContext();
+  auto &clangASTContext = getClangASTContext();
+
+  auto domainInfo = clangASTContext.getFeatureAvailInfo(domainName);
+  if (domainInfo.Kind == clang::FeatureAvailKind::None)
     return;
 
-  auto varDecl = lookupTable->lookupAvailabilityDomainDecl(identifier.str());
+  auto *varDecl = dyn_cast_or_null<clang::VarDecl>(domainInfo.Decl);
   if (!varDecl)
     return;
 
-  auto featureInfo = getClangASTContext().getFeatureAvailInfo(varDecl);
-  if (featureInfo.first.empty())
+  // The decl that was found may belong to a different Clang module.
+  if (varDecl->getOwningModule() != getClangModule())
     return;
 
-  auto getDomainKind = [](clang::FeatureAvailKind featureAvailKind) {
-    switch (featureAvailKind) {
-    case clang::FeatureAvailKind::None:
-      llvm_unreachable("unexpected kind");
-    case clang::FeatureAvailKind::Available:
-      return CustomAvailabilityDomain::Kind::Enabled;
-    case clang::FeatureAvailKind::Unavailable:
-      return CustomAvailabilityDomain::Kind::Disabled;
-    case clang::FeatureAvailKind::Dynamic:
-      return CustomAvailabilityDomain::Kind::Dynamic;
-    }
-  };
+  auto *imported = dyn_cast_or_null<ValueDecl>(
+      ctx.getClangModuleLoader()->importDeclDirectly(varDecl));
+  if (!imported)
+    return;
 
-  auto domain = AvailabilityDomain::forCustom(CustomAvailabilityDomain::get(
-      featureInfo.first, getParentModule(),
-      getDomainKind(featureInfo.second.Kind), getASTContext()));
-  results.push_back(domain);
+  auto customDomain = AvailabilityDomain::forCustom(imported);
+  ASSERT(customDomain);
+  results.push_back(*customDomain);
 }
 
 void ClangModuleUnit::collectLinkLibraries(
@@ -4185,7 +4228,7 @@ clang::TargetInfo &ClangImporter::getModuleAvailabilityTarget() const {
 }
 
 clang::TargetInfo &ClangImporter::getTargetInfo() const {
-  return *Impl.getSwiftTargetInfo();
+  return Impl.getCodeGenTargetInfo();
 }
 
 clang::ASTContext &ClangImporter::getClangASTContext() const {
@@ -4218,7 +4261,7 @@ clang::Sema &ClangImporter::getClangSema() const {
 }
 
 clang::CodeGenOptions &ClangImporter::getCodeGenOpts() const {
-  return *Impl.getSwiftCodeGenOptions();
+  return Impl.getCodeGenOptions();
 }
 
 std::string ClangImporter::getClangModuleHash() const {
@@ -4234,8 +4277,8 @@ ClangImporter::getSwiftExplicitModuleDirectCC1Args() const {
   });
 
   clang::CompilerInvocation instance;
-  clang::DiagnosticsEngine clangDiags(new clang::DiagnosticIDs(),
-                                      new clang::DiagnosticOptions(),
+  clang::DiagnosticOptions diagOpts;
+  clang::DiagnosticsEngine clangDiags(new clang::DiagnosticIDs(), diagOpts,
                                       new clang::IgnoringDiagConsumer());
   bool success = clang::CompilerInvocation::CreateFromArgs(instance, clangArgs,
                                                            clangDiags);
@@ -4276,15 +4319,14 @@ ClangImporter::getSwiftExplicitModuleDirectCC1Args() const {
   PPOpts.MacroIncludes.clear();
   PPOpts.Includes.clear();
 
-  // CodeGenOptions.
-  auto &CGOpts = instance.getCodeGenOpts();
-  CGOpts.DebugCompilationDir.clear();
+  // Clear benign CodeGenOptions.
+  clang::tooling::dependencies::resetBenignCodeGenOptions(
+      clang::frontend::ActionKind::GenerateModule, instance.getLangOpts(),
+      instance.getCodeGenOpts());
 
-  if (Impl.SwiftContext.ClangImporterOpts.UseClangIncludeTree) {
-    // FileSystemOptions.
-    auto &FSOpts = instance.getFileSystemOpts();
-    FSOpts.WorkingDir.clear();
-  }
+  // FileSystemOptions.
+  auto &FSOpts = instance.getFileSystemOpts();
+  FSOpts.WorkingDir.clear();
 
   if (!Impl.SwiftContext.SearchPathOpts.ScannerPrefixMapper.empty()) {
     // Remap all the paths if requested.
@@ -4432,7 +4474,14 @@ ModuleDecl *ClangModuleUnit::getOverlayModule() const {
     // FIXME: Include proper source location.
     ModuleDecl *M = getParentModule();
     ASTContext &Ctx = M->getASTContext();
-    auto overlay = Ctx.getOverlayModule(this);
+
+    ModuleDecl *overlay = nullptr;
+    // During compilation of a textual interface with no formal C++ interop mode,
+    // i.e. it was built without C++ interop, avoid querying the 'CxxStdlib' overlay
+    // for it, since said overlay was not used during compilation of this module.
+    if (!importer::isCxxStdModule(clangModule) || Ctx.LangOpts.FormalCxxInteropMode)
+      overlay = Ctx.getOverlayModule(this);
+
     if (overlay) {
       Ctx.addLoadedModule(overlay);
     } else {
@@ -4452,7 +4501,8 @@ ModuleDecl *ClangModuleUnit::getOverlayModule() const {
     // If this Clang module is a part of the C++ stdlib, and we haven't loaded
     // the overlay for it so far, it is a split libc++ module (e.g. std_vector).
     // Load the CxxStdlib overlay explicitly.
-    if (!overlay && importer::isCxxStdModule(clangModule)) {
+    if (!overlay && importer::isCxxStdModule(clangModule) &&
+        Ctx.LangOpts.FormalCxxInteropMode) {
       ImportPath::Module::Builder builder(Ctx.Id_CxxStdlib);
       overlay = owner.loadModule(SourceLoc(), std::move(builder).get());
     }
@@ -4616,8 +4666,8 @@ void ClangModuleUnit::getImportedModulesForLookup(
     if (owner.SwiftContext.LangOpts.EnableCXXInterop && topLevel &&
         isCxxStdModule(topLevel) && wrapper->clangModule &&
         isCxxStdModule(wrapper->clangModule)) {
-      // The CxxStdlib overlay re-exports the clang module std, which in recent
-      // libc++ versions re-exports top-level modules for different std headers
+      // The CxxStdlib overlay re-exports the clang module std, which in libc++
+      // versions 17-19 re-exports top-level modules for different std headers
       // (std_string, std_vector, etc). The overlay module for each of the std
       // modules is the CxxStdlib module itself. Make sure we return the actual
       // clang modules (std_xyz) as transitive dependencies instead of just
@@ -4658,6 +4708,37 @@ void ClangImporter::Implementation::getMangledName(
   }
 }
 
+void ClangImporter::Implementation::configureOptionsForCodeGen(
+    clang::DiagnosticsEngine &Diags, clang::CompilerInvocation *CI) {
+  clang::TargetInfo *targetInfo = nullptr;
+  if (CI) {
+    TargetOpts.reset(new clang::TargetOptions(std::move(CI->getTargetOpts())));
+    CodeGenOpts.reset(
+        new clang::CodeGenOptions(std::move(CI->getCodeGenOpts())));
+    targetInfo = clang::TargetInfo::CreateTargetInfo(Diags, *TargetOpts);
+
+    // Ensure the target info has configured target-specific defines
+    std::string defineBuffer;
+    llvm::raw_string_ostream predefines(defineBuffer);
+    clang::MacroBuilder builder(predefines);
+    targetInfo->getTargetDefines(Instance->getLangOpts(), builder);
+  } else {
+    targetInfo =
+        clang::TargetInfo::CreateTargetInfo(Diags, Invocation->getTargetOpts());
+  }
+
+  CodeGenTargetInfo.reset(targetInfo);
+}
+
+clang::CodeGenOptions &
+ClangImporter::Implementation::getCodeGenOptions() const {
+  if (CodeGenOpts) {
+    return *CodeGenOpts.get();
+  }
+
+  return Invocation->getCodeGenOpts();
+}
+
 // ---------------------------------------------------------------------------
 // Swift lookup tables
 // ---------------------------------------------------------------------------
@@ -4970,7 +5051,7 @@ void ClangImporter::Implementation::diagnoseMemberValue(
   forEachLookupTable([&](SwiftLookupTable &table) -> bool {
     for (const auto &entry :
          table.lookup(name.getBaseName(), EffectiveClangContext(container))) {
-      if (clang::NamedDecl *nd = entry.get<clang::NamedDecl *>()) {
+      if (clang::NamedDecl *nd = cast<clang::NamedDecl *>(entry)) {
         // We are only interested in members of a particular context,
         // skip other contexts.
         if (nd->getDeclContext() != container)
@@ -5024,11 +5105,26 @@ bool ClangImporter::Implementation::emitDiagnosticsForTarget(
     ImportDiagnosticTarget target, clang::SourceLocation fallbackLoc) {
   for (auto it = ImportDiagnostics[target].rbegin();
        it != ImportDiagnostics[target].rend(); ++it) {
-    HeaderLoc loc = HeaderLoc(it->loc.isValid() ? it->loc : fallbackLoc);
+    clang::SourceLocation loc = it->loc.isValid() ? it->loc : fallbackLoc;
+    HeaderLoc hdrLoc(loc);
+    if (const auto *declTarget = target.dyn_cast<const clang::Decl *>()) {
+      if (const auto *func = llvm::dyn_cast<clang::FunctionDecl>(declTarget)) {
+        if (func->isTemplateInstantiation()) {
+          if (const auto *pattern = func->getTemplateInstantiationPattern()) {
+            std::pair<const clang::FunctionDecl *, DiagID> key = {
+                pattern, it->diag.getID()};
+            if (!DiagnosedTemplateDiagnostics.insert(key).second)
+              continue;
+            hdrLoc = HeaderLoc(pattern->getLocation());
+          }
+        }
+      }
+    }
+
     if (it->diag.getID() == diag::record_not_automatically_importable.ID) {
-      diagnoseForeignReferenceTypeFixit(*this, loc, it->diag);
+      diagnoseForeignReferenceTypeFixit(*this, hdrLoc, it->diag);
     } else {
-      diagnose(loc, it->diag);
+      diagnose(hdrLoc, it->diag);
     }
   }
   return ImportDiagnostics[target].size();
@@ -5179,7 +5275,7 @@ TinyPtrVector<ValueDecl *> CXXNamespaceMemberLookup::evaluate(
         {});
 
     for (auto found : allResults) {
-      auto clangMember = found.get<clang::NamedDecl *>();
+      auto clangMember = cast<clang::NamedDecl *>(found);
       auto it = importedDecls.insert(clangMember);
       // Skip over members already found during lookup in
       // prior redeclarations.
@@ -5194,7 +5290,7 @@ TinyPtrVector<ValueDecl *> CXXNamespaceMemberLookup::evaluate(
   return result;
 }
 
-static const llvm::StringMap<std::vector<int>> STLConditionalEscapableParams{
+static const llvm::StringMap<std::vector<int>> STLConditionalParams{
     {"basic_string", {0}},
     {"vector", {0}},
     {"array", {0}},
@@ -5224,16 +5320,66 @@ static const llvm::StringMap<std::vector<int>> STLConditionalEscapableParams{
     {"unordered_multimap", {0, 1}},
 };
 
+template <typename Kind>
+static std::optional<Kind> checkConditionalParams(
+    clang::RecordDecl *recordDecl, const std::vector<int> &STLParams,
+    std::set<StringRef> &conditionalParams,
+    std::function<std::optional<Kind>(clang::TemplateArgument &, StringRef)>
+        &checkArg) {
+  auto specDecl = cast<clang::ClassTemplateSpecializationDecl>(recordDecl);
+  SmallVector<std::pair<unsigned, StringRef>, 4> argumentsToCheck;
+  bool hasInjectedSTLAnnotation = !STLParams.empty();
+  while (specDecl) {
+    auto templateDecl = specDecl->getSpecializedTemplate();
+    if (hasInjectedSTLAnnotation) {
+      auto params = templateDecl->getTemplateParameters();
+      for (auto idx : STLParams)
+        argumentsToCheck.push_back(
+            std::make_pair(idx, params->getParam(idx)->getName()));
+    } else {
+      for (auto [idx, param] :
+           llvm::enumerate(*templateDecl->getTemplateParameters())) {
+        if (conditionalParams.erase(param->getName()))
+          argumentsToCheck.push_back(std::make_pair(idx, param->getName()));
+      }
+    }
+    auto &argList = specDecl->getTemplateArgs();
+    for (auto argToCheck : argumentsToCheck) {
+      auto arg = argList[argToCheck.first];
+      llvm::SmallVector<clang::TemplateArgument, 1> nonPackArgs;
+      if (arg.getKind() == clang::TemplateArgument::Pack) {
+        auto pack = arg.getPackAsArray();
+        nonPackArgs.assign(pack.begin(), pack.end());
+      } else
+        nonPackArgs.push_back(arg);
+      for (auto nonPackArg : nonPackArgs) {
+        auto result = checkArg(nonPackArg, argToCheck.second);
+        if (result.has_value())
+          return result.value();
+      }
+    }
+    if (hasInjectedSTLAnnotation)
+      break;
+    clang::DeclContext *dc = specDecl;
+    specDecl = nullptr;
+    while ((dc = dc->getParent())) {
+      specDecl = dyn_cast<clang::ClassTemplateSpecializationDecl>(dc);
+      if (specDecl)
+        break;
+    }
+  }
+  return std::nullopt;
+}
+
 static std::set<StringRef>
-getConditionalEscapableAttrParams(const clang::RecordDecl *decl) {
+getConditionalAttrParams(const clang::RecordDecl *decl, StringRef attrName) {
   std::set<StringRef> result;
   if (!decl->hasAttrs())
     return result;
   for (auto attr : decl->getAttrs()) {
-    if (auto swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr))
-      if (swiftAttr->getAttribute().starts_with("escapable_if:")) {
-        StringRef params = swiftAttr->getAttribute().drop_front(
-            StringRef("escapable_if:").size());
+    if (auto swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr)) {
+      StringRef params = swiftAttr->getAttribute();
+      if (params.consume_front(attrName)) {
         auto commaPos = params.find(',');
         StringRef nextParam = params.take_front(commaPos);
         while (!nextParam.empty() && commaPos != StringRef::npos) {
@@ -5243,10 +5389,21 @@ getConditionalEscapableAttrParams(const clang::RecordDecl *decl) {
           nextParam = params.take_front(commaPos);
         }
       }
+    }
   }
   return result;
 }
 
+static std::set<StringRef>
+getConditionalEscapableAttrParams(const clang::RecordDecl *decl) {
+  return getConditionalAttrParams(decl, "escapable_if:");
+}
+
+static std::set<StringRef>
+getConditionalCopyableAttrParams(const clang::RecordDecl *decl) {
+  return getConditionalAttrParams(decl, "copyable_if:");
+}
+
 CxxEscapability
 ClangTypeEscapability::evaluate(Evaluator &evaluator,
                                 EscapabilityLookupDescriptor desc) const {
@@ -5270,62 +5427,35 @@ ClangTypeEscapability::evaluate(Evaluator &evaluator,
       return CxxEscapability::Escapable;
     auto injectedStlAnnotation =
         recordDecl->isInStdNamespace()
-            ? STLConditionalEscapableParams.find(recordDecl->getName())
-            : STLConditionalEscapableParams.end();
-    bool hasInjectedSTLAnnotation =
-        injectedStlAnnotation != STLConditionalEscapableParams.end();
+            ? STLConditionalParams.find(recordDecl->getName())
+            : STLConditionalParams.end();
+    auto STLParams = injectedStlAnnotation != STLConditionalParams.end()
+                         ? injectedStlAnnotation->second
+                         : std::vector<int>();
     auto conditionalParams = getConditionalEscapableAttrParams(recordDecl);
-    if (!conditionalParams.empty() || hasInjectedSTLAnnotation) {
-      auto specDecl = cast<clang::ClassTemplateSpecializationDecl>(recordDecl);
-      SmallVector<std::pair<unsigned, StringRef>, 4> argumentsToCheck;
+
+    if (!STLParams.empty() || !conditionalParams.empty()) {
       HeaderLoc loc{recordDecl->getLocation()};
-      while (specDecl) {
-        auto templateDecl = specDecl->getSpecializedTemplate();
-        if (hasInjectedSTLAnnotation) {
-          auto params = templateDecl->getTemplateParameters();
-          for (auto idx : injectedStlAnnotation->second)
-            argumentsToCheck.push_back(
-                std::make_pair(idx, params->getParam(idx)->getName()));
-        } else {
-          for (auto [idx, param] :
-               llvm::enumerate(*templateDecl->getTemplateParameters())) {
-            if (conditionalParams.erase(param->getName()))
-              argumentsToCheck.push_back(std::make_pair(idx, param->getName()));
-          }
+      std::function checkArgEscapability =
+          [&](clang::TemplateArgument &arg,
+              StringRef argToCheck) -> std::optional<CxxEscapability> {
+        if (arg.getKind() != clang::TemplateArgument::Type && desc.impl) {
+          desc.impl->diagnose(loc, diag::type_template_parameter_expected,
+                              argToCheck);
+          return CxxEscapability::Unknown;
         }
-        auto &argList = specDecl->getTemplateArgs();
-        for (auto argToCheck : argumentsToCheck) {
-          auto arg = argList[argToCheck.first];
-          llvm::SmallVector<clang::TemplateArgument, 1> nonPackArgs;
-          if (arg.getKind() == clang::TemplateArgument::Pack) {
-            auto pack = arg.getPackAsArray();
-            nonPackArgs.assign(pack.begin(), pack.end());
-          } else
-            nonPackArgs.push_back(arg);
-          for (auto nonPackArg : nonPackArgs) {
-            if (nonPackArg.getKind() != clang::TemplateArgument::Type &&
-                desc.impl) {
-              desc.impl->diagnose(loc, diag::type_template_parameter_expected,
-                                  argToCheck.second);
-              return CxxEscapability::Unknown;
-            }
 
-            auto argEscapability = evaluateEscapability(
-                nonPackArg.getAsType()->getUnqualifiedDesugaredType());
-            if (argEscapability == CxxEscapability::NonEscapable)
-              return CxxEscapability::NonEscapable;
-          }
-        }
-        if (hasInjectedSTLAnnotation)
-          break;
-        clang::DeclContext *dc = specDecl;
-        specDecl = nullptr;
-        while ((dc = dc->getParent())) {
-          specDecl = dyn_cast<clang::ClassTemplateSpecializationDecl>(dc);
-          if (specDecl)
-            break;
-        }
-      }
+        auto argEscapability = evaluateEscapability(
+            arg.getAsType()->getUnqualifiedDesugaredType());
+        if (argEscapability == CxxEscapability::NonEscapable)
+          return CxxEscapability::NonEscapable;
+        return std::nullopt;
+      };
+
+      auto result = checkConditionalParams<CxxEscapability>(
+          recordDecl, STLParams, conditionalParams, checkArgEscapability);
+      if (result.has_value())
+        return result.value();
 
       if (desc.impl)
         for (auto name : conditionalParams)
@@ -5336,7 +5466,8 @@ ClangTypeEscapability::evaluate(Evaluator &evaluator,
     if (desc.annotationOnly)
       return CxxEscapability::Unknown;
     auto cxxRecordDecl = dyn_cast<clang::CXXRecordDecl>(recordDecl);
-    if (!cxxRecordDecl || cxxRecordDecl->isAggregate()) {
+    if (recordDecl->getDefinition() &&
+        (!cxxRecordDecl || cxxRecordDecl->isAggregate())) {
       if (cxxRecordDecl) {
         for (auto base : cxxRecordDecl->bases()) {
           auto baseEscapability = evaluateEscapability(
@@ -5365,6 +5496,14 @@ ClangTypeEscapability::evaluate(Evaluator &evaluator,
         ClangTypeEscapability({elemTy, desc.impl, desc.annotationOnly}),
         CxxEscapability::Unknown);
   }
+  if (const auto *vecTy = desugared->getAs<clang::VectorType>()) {
+    return evaluateOrDefault(
+        evaluator,
+        ClangTypeEscapability(
+            {vecTy->getElementType()->getUnqualifiedDesugaredType(), desc.impl,
+             desc.annotationOnly}),
+        CxxEscapability::Unknown);
+  }
 
   // Base cases
   if (desugared->isAnyPointerType() || desugared->isBlockPointerType() ||
@@ -5563,10 +5702,11 @@ const clang::CXXMethodDecl *getCalledBaseCxxMethod(FuncDecl *baseMember) {
 
 // Construct a Swift method that represents the synthesized C++ method
 // that invokes the base C++ method.
-FuncDecl *synthesizeBaseFunctionDeclCall(ClangImporter &impl, ASTContext &ctx,
-                                         NominalTypeDecl *derivedStruct,
-                                         NominalTypeDecl *baseStruct,
-                                         FuncDecl *baseMember) {
+static FuncDecl *synthesizeBaseFunctionDeclCall(ClangImporter &impl,
+                                                ASTContext &ctx,
+                                                NominalTypeDecl *derivedStruct,
+                                                NominalTypeDecl *baseStruct,
+                                                FuncDecl *baseMember) {
   auto *cxxMethod = getCalledBaseCxxMethod(baseMember);
   if (!cxxMethod)
     return nullptr;
@@ -6262,7 +6402,7 @@ static ValueDecl *cloneBaseMemberDecl(ValueDecl *decl, DeclContext *newContext,
     auto out = new (rawMemory) TypeAliasDecl(
         typeDecl->getLoc(), typeDecl->getLoc(), typeDecl->getName(),
         typeDecl->getLoc(), nullptr, newContext);
-    out->setUnderlyingType(typeDecl->getInterfaceType());
+    out->setUnderlyingType(typeDecl->getDeclaredInterfaceType());
     out->setAccess(access);
     inheritance.setUnavailableIfNecessary(decl, out);
     return out;
@@ -6302,7 +6442,7 @@ TinyPtrVector<ValueDecl *> ClangRecordMemberLookup::evaluate(
   // Find the results that are actually a member of "recordDecl".
   ClangModuleLoader *clangModuleLoader = ctx.getClangModuleLoader();
   for (auto foundEntry : directResults) {
-    auto found = foundEntry.get<clang::NamedDecl *>();
+    auto found = cast<clang::NamedDecl *>(foundEntry);
     if (dyn_cast<clang::Decl>(found->getDeclContext()) !=
         recordDecl->getClangDecl())
       continue;
@@ -6355,7 +6495,8 @@ TinyPtrVector<ValueDecl *> ClangRecordMemberLookup::evaluate(
          cast<NominalTypeDecl>(recordDecl)->getCurrentMembersWithoutLoading()) {
       auto namedMember = dyn_cast<ValueDecl>(member);
       if (!namedMember || !namedMember->hasName() ||
-          namedMember->getName().getBaseName() != name)
+          namedMember->getName().getBaseName() != name ||
+          clangModuleLoader->getOriginalForClonedMember(namedMember))
         continue;
 
       auto *imported = clangModuleLoader->importBaseMemberDecl(
@@ -6368,16 +6509,15 @@ TinyPtrVector<ValueDecl *> ClangRecordMemberLookup::evaluate(
   }
 
   // If this is a C++ record, look through any base classes.
-  if (auto cxxRecord =
-          dyn_cast<clang::CXXRecordDecl>(recordDecl->getClangDecl())) {
+  const clang::CXXRecordDecl *cxxRecord;
+  if ((cxxRecord = dyn_cast<clang::CXXRecordDecl>(recordDecl->getClangDecl())) &&
+      cxxRecord->isCompleteDefinition()) {
     // Capture the arity of already found members in the
     // current record, to avoid adding ambiguous members
     // from base classes.
-    const auto getArity =
-        ClangImporter::Implementation::getImportedBaseMemberDeclArity;
-    llvm::SmallSet<size_t, 4> foundNameArities;
+    llvm::SmallSet<DeclName, 4> foundMethodNames;
     for (const auto *valueDecl : result)
-      foundNameArities.insert(getArity(valueDecl));
+      foundMethodNames.insert(valueDecl->getName());
 
     for (auto base : cxxRecord->bases()) {
       if (skipIfNonPublic && base.getAccessSpecifier() != clang::AS_public)
@@ -6390,6 +6530,11 @@ TinyPtrVector<ValueDecl *> ClangRecordMemberLookup::evaluate(
         continue;
 
       auto *baseRecord = baseType->getAs<clang::RecordType>()->getDecl();
+
+      if (isSymbolicCircularBase(cxxRecord, baseRecord))
+        // Skip circular bases to avoid unbounded recursion
+        continue;
+
       if (auto import = clangModuleLoader->importDeclDirectly(baseRecord)) {
         // If we are looking up the base class, go no further. We will have
         // already found it during the other lookup.
@@ -6406,9 +6551,9 @@ TinyPtrVector<ValueDecl *> ClangRecordMemberLookup::evaluate(
             {});
 
         for (auto foundInBase : baseResults) {
-          // Do not add duplicate entry with the same arity,
+          // Do not add duplicate entry with the same DeclName,
           // as that would cause an ambiguous lookup.
-          if (foundNameArities.count(getArity(foundInBase)))
+          if (foundMethodNames.count(foundInBase->getName()))
             continue;
 
           collector.add(foundInBase);
@@ -6544,15 +6689,23 @@ static void lookupRelatedFuncs(AbstractFunctionDecl *func,
   else
     swiftName = func->getName();
 
-  NLOptions options = NL_IgnoreAccessControl | NL_IgnoreMissingImports;
   if (auto ty = func->getDeclContext()->getSelfNominalTypeDecl()) {
+    NLOptions options = NL_IgnoreAccessControl | NL_IgnoreMissingImports;
     ty->lookupQualified({ ty }, DeclNameRef(swiftName), func->getLoc(),
                         NL_QualifiedDefault | options, results);
   }
   else {
-    auto mod = func->getDeclContext()->getParentModule();
-    mod->lookupQualified(mod, DeclNameRef(swiftName), func->getLoc(),
-                         NL_RemoveOverridden | options, results);
+    ASTContext &ctx = func->getASTContext();
+    UnqualifiedLookupOptions options =
+      UnqualifiedLookupFlags::IgnoreAccessControl;
+    UnqualifiedLookupDescriptor descriptor(
+        DeclNameRef(ctx, Identifier(), swiftName), func->getDeclContext(),
+        func->getLoc(), options);
+    auto lookup = evaluateOrDefault(func->getASTContext().evaluator,
+                                    UnqualifiedLookupRequest{descriptor}, {});
+    for (const auto &result : lookup) {
+      results.push_back(result.getValueDecl());
+    }
   }
 }
 
@@ -6838,8 +6991,9 @@ ClangImporter::Implementation::loadNamedMembers(
   if (CD) {
     for (auto entry : table->lookup(SerializedSwiftName(N),
                                     effectiveClangContext)) {
-      if (!entry.is<clang::NamedDecl *>()) continue;
-      auto member = entry.get<clang::NamedDecl *>();
+      if (!isa<clang::NamedDecl *>(entry))
+        continue;
+      auto member = cast<clang::NamedDecl *>(entry);
       if (!isVisibleClangEntry(member)) continue;
 
       // Skip Decls from different clang::DeclContexts
@@ -6871,8 +7025,9 @@ ClangImporter::Implementation::loadNamedMembers(
 
   for (auto entry : table->lookupGlobalsAsMembers(SerializedSwiftName(N),
                                                   effectiveClangContext)) {
-    if (!entry.is<clang::NamedDecl *>()) continue;
-    auto member = entry.get<clang::NamedDecl *>();
+    if (!isa<clang::NamedDecl *>(entry))
+      continue;
+    auto member = cast<clang::NamedDecl *>(entry);
     if (!isVisibleClangEntry(member)) continue;
 
     // Skip Decls from different clang::DeclContexts. We don't do this for
@@ -7136,18 +7291,17 @@ clang::FunctionDecl *ClangImporter::instantiateCXXFunctionTemplate(
     // TODO: Use the location of the apply here.
     // TODO: This error message should not reference implementation details.
     // See: https://github.com/apple/swift/pull/33053#discussion_r477003350
-    ctx.Diags.diagnose(SourceLoc(), diag::unable_to_convert_generic_swift_types,
-                       getFuncName(), failedTypesStr);
+    Impl.diagnose(HeaderLoc(func->getBeginLoc()),
+                  diag::unable_to_convert_generic_swift_types, getFuncName(),
+                  failedTypesStr);
     return nullptr;
   }
 
   // Instantiate a specialization of this template using the substitution map.
   auto *templateArgList = clang::TemplateArgumentList::CreateCopy(
       func->getASTContext(), templateSubst);
-  auto &sema = getClangInstance().getSema();
-  auto *spec = sema.InstantiateFunctionDeclaration(func, templateArgList,
-                                                   clang::SourceLocation());
-  if (!spec) {
+
+  auto diagnoseSubstFail = [&]() {
     std::string templateParams;
     llvm::raw_string_ostream templateParamsStream(templateParams);
     llvm::interleaveComma(templateArgList->asArray(), templateParamsStream,
@@ -7156,12 +7310,27 @@ clang::FunctionDecl *ClangImporter::instantiateCXXFunctionTemplate(
                                       templateParamsStream,
                                       /*IncludeType*/ true);
                           });
-    ctx.Diags.diagnose(SourceLoc(),
-                       diag::unable_to_substitute_cxx_function_template,
-                       getFuncName(), templateParams);
+    Impl.diagnose(HeaderLoc(func->getBeginLoc()),
+                  diag::unable_to_substitute_cxx_function_template,
+                  getFuncName(), templateParams);
+  };
+
+  auto &sema = getClangInstance().getSema();
+  auto *spec = sema.InstantiateFunctionDeclaration(func, templateArgList,
+                                                   clang::SourceLocation());
+  if (!spec || spec->isInvalidDecl()) {
+    diagnoseSubstFail();
     return nullptr;
   }
+
   sema.InstantiateFunctionDefinition(clang::SourceLocation(), spec);
+  // Even if the declaration can be instantiated, the definition may contain
+  // a substitution failure that renders spec invalid as a side-effect.
+  if (spec->isInvalidDecl()) {
+    diagnoseSubstFail();
+    return nullptr;
+  }
+
   return spec;
 }
 
@@ -7175,7 +7344,8 @@ ClangImporter::instantiateCXXClassTemplate(
     ctsd = clang::ClassTemplateSpecializationDecl::Create(
         decl->getASTContext(), decl->getTemplatedDecl()->getTagKind(),
         decl->getDeclContext(), decl->getTemplatedDecl()->getBeginLoc(),
-        decl->getLocation(), decl, arguments, nullptr);
+        decl->getLocation(), decl, arguments, /*StrictPackMatch*/ false,
+        nullptr);
     decl->AddSpecialization(ctsd, InsertPos);
   }
 
@@ -7557,6 +7727,12 @@ ClangImporter::getCXXFunctionTemplateSpecialization(SubstitutionMap subst,
   assert(isa<clang::FunctionTemplateDecl>(decl->getClangDecl()) &&
          "This API should only be used with function templates.");
 
+  // If we hit some instantiation failure and expect the compiler to imminently
+  // terminate (with an error), return some reasonable-looking placeholder value
+  // in the meantime because callers expect this function to return some
+  // non-empty ConcreteDeclRef.
+  auto failurePlaceholder = [&]() { return ConcreteDeclRef(decl); };
+
   auto *newFn =
       decl->getASTContext()
           .getClangModuleLoader()
@@ -7565,31 +7741,28 @@ ClangImporter::getCXXFunctionTemplateSpecialization(SubstitutionMap subst,
               const_cast<clang::FunctionTemplateDecl *>(
                   cast<clang::FunctionTemplateDecl>(decl->getClangDecl())),
               subst);
-  // We failed to specialize this function template. The compiler is going to
-  // exit soon. Return something valid in the meantime.
   if (!newFn)
-    return ConcreteDeclRef(decl);
+    return failurePlaceholder();
 
   auto [fnIt, inserted] =
       Impl.specializedFunctionTemplates.try_emplace(newFn, nullptr);
   if (!inserted)
     return ConcreteDeclRef(fnIt->second);
 
-  auto newDecl = cast_or_null<ValueDecl>(
-      decl->getASTContext().getClangModuleLoader()->importDeclDirectly(
-          newFn));
+  auto *newDecl = cast_or_null<ValueDecl>(
+      decl->getASTContext().getClangModuleLoader()->importDeclDirectly(newFn));
+  if (!newDecl)
+    return failurePlaceholder();
 
-  if (auto fn = dyn_cast<AbstractFunctionDecl>(newDecl)) {
+  if (auto *fn = dyn_cast<AbstractFunctionDecl>(newDecl)) {
     if (!subst.empty()) {
       newDecl = rewriteIntegerTypes(subst, decl, fn);
     }
   }
 
-  if (auto fn = dyn_cast<FuncDecl>(decl)) {
+  if (auto *fn = dyn_cast<FuncDecl>(decl)) {
     newDecl = addThunkForDependentTypes(fn, cast<FuncDecl>(newDecl));
-  }
 
-  if (auto fn = dyn_cast<FuncDecl>(decl)) {
     if (newFn->getNumParams() != fn->getParameters()->size()) {
       newDecl = generateThunkForExtraMetatypes(subst, fn,
                                                cast<FuncDecl>(newDecl));
@@ -7677,6 +7850,14 @@ ClangImporter::getDefaultArgGenerator(const clang::ParmVarDecl *param) {
   return nullptr;
 }
 
+FuncDecl *
+ClangImporter::getAvailabilityDomainPredicate(const clang::VarDecl *var) {
+  auto it = Impl.availabilityDomainPredicates.find(var);
+  if (it != Impl.availabilityDomainPredicates.end())
+    return it->second;
+  return nullptr;
+}
+
 SwiftLookupTable *
 ClangImporter::findLookupTable(const clang::Module *clangModule) {
   return Impl.findLookupTable(clangModule);
@@ -7702,12 +7883,28 @@ ValueDecl *ClangImporter::Implementation::importBaseMemberDecl(
   auto known = clonedBaseMembers.find(key);
   if (known == clonedBaseMembers.end()) {
     ValueDecl *cloned = cloneBaseMemberDecl(decl, newContext, inheritance);
+    handleAmbiguousSwiftName(cloned);
     known = clonedBaseMembers.insert({key, cloned}).first;
+    clonedMembers.insert(std::make_pair(cloned, decl));
   }
 
   return known->second;
 }
 
+ValueDecl *ClangImporter::Implementation::getOriginalForClonedMember(
+    const ValueDecl *decl) {
+  // If this is a cloned decl, we don't want to reclone it
+  // Otherwise, we may end up with multiple copies of the same method
+  if (!decl->hasClangNode()) {
+    // Skip decls with a clang node as those will never be a clone
+    auto result = clonedMembers.find(decl);
+    if (result != clonedMembers.end())
+      return result->getSecond();
+  }
+
+  return nullptr;
+}
+
 size_t ClangImporter::Implementation::getImportedBaseMemberDeclArity(
     const ValueDecl *valueDecl) {
   if (auto *func = dyn_cast<FuncDecl>(valueDecl)) {
@@ -7724,6 +7921,10 @@ ClangImporter::importBaseMemberDecl(ValueDecl *decl, DeclContext *newContext,
   return Impl.importBaseMemberDecl(decl, newContext, inheritance);
 }
 
+ValueDecl *ClangImporter::getOriginalForClonedMember(const ValueDecl *decl) {
+  return Impl.getOriginalForClonedMember(decl);
+}
+
 void ClangImporter::diagnoseTopLevelValue(const DeclName &name) {
   Impl.diagnoseTopLevelValue(name);
 }
@@ -7803,7 +8004,7 @@ ClangImporter::createEmbeddedBridgingHeaderCacheKey(
                    "ChainedHeaderIncludeTree -> EmbeddedHeaderIncludeTree");
 }
 
-static bool hasImportAsRefAttr(const clang::RecordDecl *decl) {
+bool importer::hasImportAsRefAttr(const clang::RecordDecl *decl) {
   return decl->hasAttrs() && llvm::any_of(decl->getAttrs(), [](auto *attr) {
            if (auto swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr))
              return swiftAttr->getAttribute() == "import_reference" ||
@@ -7814,20 +8015,6 @@ static bool hasImportAsRefAttr(const clang::RecordDecl *decl) {
          });
 }
 
-// Is this a pointer to a foreign reference type.
-bool importer::isForeignReferenceTypeWithoutImmortalAttrs(const clang::QualType type) {
-  if (!type->isPointerType())
-    return false;
-
-  auto pointeeType =
-      dyn_cast<clang::RecordType>(type->getPointeeType().getCanonicalType());
-  if (pointeeType == nullptr)
-    return false;
-
-  return hasImportAsRefAttr(pointeeType->getDecl()) &&
-         !hasImmortalAttrs(pointeeType->getDecl());
-}
-
 static bool hasDiamondInheritanceRefType(const clang::CXXRecordDecl *decl) {
   if (!decl->hasDefinition() || decl->isDependentType())
     return false;
@@ -7868,10 +8055,6 @@ getRefParentDecls(const clang::RecordDecl *decl, ASTContext &ctx,
                                  decl);
           importerImpl->DiagnosedCxxRefDecls.insert(decl);
         }
-      } else {
-        ctx.Diags.diagnose({}, diag::cant_infer_frt_in_cxx_inheritance, decl);
-        assert(false && "nullpointer passeed for importerImpl when calling "
-                        "getRefParentOrDiag");
       }
       return matchingDecls;
     }
@@ -7885,10 +8068,28 @@ getRefParentDecls(const clang::RecordDecl *decl, ASTContext &ctx,
   return matchingDecls;
 }
 
-static llvm::SmallVector<ValueDecl *, 1>
-getValueDeclsForName(const clang::Decl *decl, ASTContext &ctx, StringRef name) {
+llvm::SmallVector<ValueDecl *, 1>
+importer::getValueDeclsForName(NominalTypeDecl *decl, StringRef name) {
+  // If the name is empty, don't try to find any decls.
+  if (name.empty())
+    return {};
+
+  auto &ctx = decl->getASTContext();
+  auto clangDecl = decl->getClangDecl();
   llvm::SmallVector<ValueDecl *, 1> results;
-  auto *clangMod = decl->getOwningModule();
+
+  if (name.starts_with(".")) {
+    // Look for a member of decl instead of a global.
+    StringRef memberName = name.drop_front(1);
+    if (memberName.empty())
+      return {};
+    auto declName = DeclName(ctx.getIdentifier(memberName));
+    auto allResults = evaluateOrDefault(
+        ctx.evaluator, ClangRecordMemberLookup({decl, declName}), {});
+    return SmallVector<ValueDecl *, 1>(allResults.begin(), allResults.end());
+  }
+
+  auto *clangMod = clangDecl->getOwningModule();
   if (clangMod && clangMod->isSubModule())
     clangMod = clangMod->getTopLevelModule();
   if (clangMod) {
@@ -7946,10 +8147,6 @@ getRefParentOrDiag(const clang::RecordDecl *decl, ASTContext &ctx,
                                decl);
         importerImpl->DiagnosedCxxRefDecls.insert(decl);
       }
-    } else {
-      ctx.Diags.diagnose({}, diag::cant_infer_frt_in_cxx_inheritance, decl);
-      assert(false && "nullpointer passed for importerImpl when calling "
-                      "getRefParentOrDiag");
     }
     return nullptr;
   }
@@ -8006,7 +8203,7 @@ bool importer::hasIteratorAPIAttr(const clang::Decl *decl) {
   return hasSwiftAttribute(decl, "import_iterator");
 }
 
-static bool hasNonCopyableAttr(const clang::RecordDecl *decl) {
+bool importer::hasNonCopyableAttr(const clang::RecordDecl *decl) {
   return hasSwiftAttribute(decl, "~Copyable");
 }
 
@@ -8068,87 +8265,13 @@ bool importer::isViewType(const clang::CXXRecordDecl *decl) {
   return !hasOwnedValueAttr(decl) && hasPointerInSubobjects(decl);
 }
 
-static bool copyConstructorIsDefaulted(const clang::CXXRecordDecl *decl) {
-  auto ctor = llvm::find_if(decl->ctors(), [](clang::CXXConstructorDecl *ctor) {
-    return ctor->isCopyConstructor();
-  });
-
-  assert(ctor != decl->ctor_end());
-  return ctor->isDefaulted();
-}
-
-static bool copyAssignOperatorIsDefaulted(const clang::CXXRecordDecl *decl) {
-  auto copyAssignOp = llvm::find_if(decl->decls(), [](clang::Decl *member) {
-    if (auto method = dyn_cast<clang::CXXMethodDecl>(member))
-      return method->isCopyAssignmentOperator();
-    return false;
-  });
-
-  assert(copyAssignOp != decl->decls_end());
-  return cast<clang::CXXMethodDecl>(*copyAssignOp)->isDefaulted();
-}
-
-/// Recursively checks that there are no user-provided copy constructors or
-/// destructors in any fields or base classes.
-/// Does not check C++ records with specific API annotations.
-static bool isSufficientlyTrivial(const clang::CXXRecordDecl *decl) {
-  // Probably a class template that has not yet been specialized:
-  if (!decl->getDefinition())
-    return true;
-
-  if ((decl->hasUserDeclaredCopyConstructor() &&
-       !copyConstructorIsDefaulted(decl)) ||
-      (decl->hasUserDeclaredCopyAssignment() &&
-       !copyAssignOperatorIsDefaulted(decl)) ||
-      (decl->hasUserDeclaredDestructor() && decl->getDestructor() &&
-       !decl->getDestructor()->isDefaulted()))
-    return false;
-
-  auto checkType = [](clang::QualType t) {
-    if (auto recordType = dyn_cast<clang::RecordType>(t.getCanonicalType())) {
-      if (auto cxxRecord =
-              dyn_cast<clang::CXXRecordDecl>(recordType->getDecl())) {
-        if (hasImportAsRefAttr(cxxRecord) || hasOwnedValueAttr(cxxRecord) ||
-            hasUnsafeAPIAttr(cxxRecord))
-          return true;
-
-        if (!isSufficientlyTrivial(cxxRecord))
-          return false;
-      }
-    }
-
-    return true;
-  };
-
-  for (auto field : decl->fields()) {
-    if (!checkType(field->getType()))
-      return false;
-  }
-
-  for (auto base : decl->bases()) {
-    if (!checkType(base.getType()))
-      return false;
-  }
-
-  return true;
-}
-
-/// Checks if a record provides the required value type lifetime operations
-/// (copy and destroy).
 static bool hasCopyTypeOperations(const clang::CXXRecordDecl *decl) {
-  // Hack for a base type of std::optional from the Microsoft standard library.
-  if (decl->isInStdNamespace() && decl->getIdentifier() &&
-      decl->getName() == "_Optional_construct_base")
-    return true;
-
   if (decl->hasSimpleCopyConstructor())
     return true;
 
-  // If we have no way of copying the type we can't import the class
-  // at all because we cannot express the correct semantics as a swift
-  // struct.
   return llvm::any_of(decl->ctors(), [](clang::CXXConstructorDecl *ctor) {
     return ctor->isCopyConstructor() && !ctor->isDeleted() &&
+           !ctor->isIneligibleOrNotSelected() &&
            // FIXME: Support default arguments (rdar://142414553)
            ctor->getNumParams() == 1 &&
            ctor->getAccess() == clang::AccessSpecifier::AS_public;
@@ -8156,25 +8279,22 @@ static bool hasCopyTypeOperations(const clang::CXXRecordDecl *decl) {
 }
 
 static bool hasMoveTypeOperations(const clang::CXXRecordDecl *decl) {
-  // If we have no way of copying the type we can't import the class
-  // at all because we cannot express the correct semantics as a swift
-  // struct.
-  if (llvm::any_of(decl->ctors(), [](clang::CXXConstructorDecl *ctor) {
-        return ctor->isMoveConstructor() &&
-               (ctor->isDeleted() || ctor->getAccess() != clang::AS_public);
-      }))
-    return false;
+  if (decl->hasSimpleMoveConstructor())
+    return true;
 
   return llvm::any_of(decl->ctors(), [](clang::CXXConstructorDecl *ctor) {
-    return ctor->isMoveConstructor() &&
+    return ctor->isMoveConstructor() && !ctor->isDeleted() &&
+           !ctor->isIneligibleOrNotSelected() &&
            // FIXME: Support default arguments (rdar://142414553)
-           ctor->getNumParams() == 1;
+           ctor->getNumParams() == 1 &&
+           ctor->getAccess() == clang::AS_public;
   });
 }
 
 static bool hasDestroyTypeOperations(const clang::CXXRecordDecl *decl) {
   if (auto dtor = decl->getDestructor()) {
-    if (dtor->isDeleted() || dtor->getAccess() != clang::AS_public) {
+    if (dtor->isDeleted() || dtor->isIneligibleOrNotSelected() ||
+        dtor->getAccess() != clang::AS_public) {
       return false;
     }
     return true;
@@ -8230,46 +8350,17 @@ CxxRecordSemantics::evaluate(Evaluator &evaluator,
 
   auto cxxDecl = dyn_cast<clang::CXXRecordDecl>(decl);
   if (!cxxDecl) {
-    return CxxRecordSemanticsKind::Trivial;
+    return CxxRecordSemanticsKind::Value;
   }
 
   if (isSwiftClassType(cxxDecl))
     return CxxRecordSemanticsKind::SwiftClassType;
 
-  if (!hasDestroyTypeOperations(cxxDecl) ||
-      (!hasCopyTypeOperations(cxxDecl) && !hasMoveTypeOperations(cxxDecl))) {
-
-    if (hasConstructorWithUnsupportedDefaultArgs(cxxDecl))
-      return CxxRecordSemanticsKind::UnavailableConstructors;
-
-    return CxxRecordSemanticsKind::MissingLifetimeOperation;
-  }
-
-  if (hasNonCopyableAttr(cxxDecl) && hasMoveTypeOperations(cxxDecl)) {
-    return CxxRecordSemanticsKind::MoveOnly;
-  }
-
-  if (hasOwnedValueAttr(cxxDecl)) {
-    return CxxRecordSemanticsKind::Owned;
-  }
-
   if (hasIteratorAPIAttr(cxxDecl) || isIterator(cxxDecl)) {
     return CxxRecordSemanticsKind::Iterator;
   }
 
-  if (hasCopyTypeOperations(cxxDecl)) {
-    return CxxRecordSemanticsKind::Owned;
-  }
-
-  if (hasMoveTypeOperations(cxxDecl)) {
-    return CxxRecordSemanticsKind::MoveOnly;
-  }
-
-  if (isSufficientlyTrivial(cxxDecl)) {
-    return CxxRecordSemanticsKind::Trivial;
-  }
-
-  llvm_unreachable("Could not classify C++ type.");
+  return CxxRecordSemanticsKind::Value;
 }
 
 ValueDecl *
@@ -8300,6 +8391,120 @@ CxxRecordAsSwiftType::evaluate(Evaluator &evaluator,
   return nullptr;
 }
 
+CxxValueSemanticsKind
+CxxValueSemantics::evaluate(Evaluator &evaluator,
+                            CxxValueSemanticsDescriptor desc) const {
+
+  const auto *type = desc.type;
+  auto *importerImpl = desc.importerImpl;
+
+  auto desugared = type->getUnqualifiedDesugaredType();
+  const auto *recordType = desugared->getAs<clang::RecordType>();
+  if (!recordType)
+    return CxxValueSemanticsKind::Copyable;
+
+  auto recordDecl = recordType->getDecl();
+
+  // When a reference type is copied, the pointer’s value is copied rather than
+  // the object’s storage. This means reference types can be imported as
+  // copyable to Swift, even when they are non-copyable in C++.
+  if (recordHasReferenceSemantics(recordDecl, importerImpl))
+    return CxxValueSemanticsKind::Copyable;
+
+  if (recordDecl->isInStdNamespace()) {
+    // Hack for a base type of std::optional from the Microsoft standard
+    // library.
+    if (recordDecl->getIdentifier() &&
+        recordDecl->getName() == "_Optional_construct_base")
+      return CxxValueSemanticsKind::Copyable;
+  }
+
+  if (!hasNonCopyableAttr(recordDecl)) {
+    auto injectedStlAnnotation =
+        recordDecl->isInStdNamespace()
+            ? STLConditionalParams.find(recordDecl->getName())
+            : STLConditionalParams.end();
+    auto STLParams = injectedStlAnnotation != STLConditionalParams.end()
+                         ? injectedStlAnnotation->second
+                         : std::vector<int>();
+    auto conditionalParams = getConditionalCopyableAttrParams(recordDecl);
+
+    if (!STLParams.empty() || !conditionalParams.empty()) {
+      HeaderLoc loc{recordDecl->getLocation()};
+      std::function checkArgValueSemantics =
+          [&](clang::TemplateArgument &arg,
+              StringRef argToCheck) -> std::optional<CxxValueSemanticsKind> {
+        if (arg.getKind() != clang::TemplateArgument::Type && importerImpl) {
+          importerImpl->diagnose(loc, diag::type_template_parameter_expected,
+                                 argToCheck);
+          return CxxValueSemanticsKind::Unknown;
+        }
+
+        auto argValueSemantics = evaluateOrDefault(
+            evaluator,
+            CxxValueSemantics(
+                {arg.getAsType()->getUnqualifiedDesugaredType(), importerImpl}),
+            {});
+        if (argValueSemantics != CxxValueSemanticsKind::Copyable)
+          return argValueSemantics;
+        return std::nullopt;
+      };
+
+      auto result = checkConditionalParams<CxxValueSemanticsKind>(
+          recordDecl, STLParams, conditionalParams, checkArgValueSemantics);
+      if (result.has_value())
+        return result.value();
+
+      if (importerImpl)
+        for (auto name : conditionalParams)
+          importerImpl->diagnose(loc, diag::unknown_template_parameter, name);
+
+      return CxxValueSemanticsKind::Copyable;
+    }
+  }
+
+  const auto cxxRecordDecl = dyn_cast<clang::CXXRecordDecl>(recordDecl);
+  if (!cxxRecordDecl || !cxxRecordDecl->isCompleteDefinition()) {
+    if (hasNonCopyableAttr(recordDecl))
+      return CxxValueSemanticsKind::MoveOnly;
+    return CxxValueSemanticsKind::Copyable;
+  }
+
+  bool isCopyable = !hasNonCopyableAttr(cxxRecordDecl) && 
+                    hasCopyTypeOperations(cxxRecordDecl);
+  bool isMovable = hasMoveTypeOperations(cxxRecordDecl);
+
+  if (!hasDestroyTypeOperations(cxxRecordDecl) || (!isCopyable && !isMovable)) {
+
+    if (hasConstructorWithUnsupportedDefaultArgs(cxxRecordDecl))
+      return CxxValueSemanticsKind::UnavailableConstructors;
+
+    return CxxValueSemanticsKind::MissingLifetimeOperation;
+  }
+
+  if (hasNonCopyableAttr(cxxRecordDecl) && isMovable)
+    return CxxValueSemanticsKind::MoveOnly;
+
+  if (isCopyable)
+    return CxxValueSemanticsKind::Copyable;
+
+  if (isMovable)
+    return CxxValueSemanticsKind::MoveOnly;
+
+  llvm_unreachable("Could not classify C++ type.");
+}
+
+void swift::simple_display(llvm::raw_ostream &out,
+                           CxxValueSemanticsDescriptor desc) {
+  out << "Checking if '";
+  out << clang::QualType(desc.type, 0).getAsString();
+  out << "' is copyable or movable.";
+}
+
+SourceLoc swift::extractNearestSourceLoc(CxxValueSemanticsDescriptor) {
+  return SourceLoc();
+}
+
 static bool anySubobjectsSelfContained(const clang::CXXRecordDecl *decl) {
   // std::pair and std::tuple might have copy and move constructors, or base
   // classes with copy and move constructors, but they are not self-contained
@@ -8435,6 +8640,20 @@ SourceLoc swift::extractNearestSourceLoc(SafeUseOfCxxDeclDescriptor desc) {
   return SourceLoc();
 }
 
+void swift::simple_display(llvm::raw_ostream &out,
+                           CxxDeclExplicitSafetyDescriptor desc) {
+  out << "Checking if '";
+  if (auto namedDecl = dyn_cast<clang::NamedDecl>(desc.decl))
+    out << namedDecl->getNameAsString();
+  else
+    out << "<invalid decl>";
+  out << "' is explicitly safe.\n";
+}
+
+SourceLoc swift::extractNearestSourceLoc(CxxDeclExplicitSafetyDescriptor desc) {
+  return SourceLoc();
+}
+
 CustomRefCountingOperationResult CustomRefCountingOperation::evaluate(
     Evaluator &evaluator, CustomRefCountingOperationDescriptor desc) const {
   auto swiftDecl = desc.decl;
@@ -8479,7 +8698,7 @@ CustomRefCountingOperationResult CustomRefCountingOperation::evaluate(
     return {CustomRefCountingOperationResult::immortal, nullptr, name};
 
   llvm::SmallVector<ValueDecl *, 1> results =
-      getValueDeclsForName(swiftDecl->getClangDecl(), ctx, name);
+      getValueDeclsForName(const_cast<ClassDecl*>(swiftDecl), name);
   if (results.size() == 1)
     return {CustomRefCountingOperationResult::foundOperation, results.front(),
             name};
@@ -8509,12 +8728,14 @@ static bool hasUnsafeType(Evaluator &evaluator, clang::QualType clangType) {
     // All other pointers are considered unsafe.
     return true;
   }
-  
+
   // Handle records recursively.
   if (auto recordDecl = clangType->getAsTagDecl()) {
-    auto safety =
-        evaluateOrDefault(evaluator, ClangDeclExplicitSafety({recordDecl}),
-                          ExplicitSafety::Unspecified);
+    // If we reached this point the types is not imported as a shared reference,
+    // so we don't need to check the bases whether they are shared references.
+    auto safety = evaluateOrDefault(
+        evaluator, ClangDeclExplicitSafety({recordDecl, false}),
+        ExplicitSafety::Unspecified);
     switch (safety) {
       case ExplicitSafety::Unsafe:
         return true;
@@ -8529,10 +8750,9 @@ static bool hasUnsafeType(Evaluator &evaluator, clang::QualType clangType) {
   return false;
 }
 
-ExplicitSafety ClangDeclExplicitSafety::evaluate(
-    Evaluator &evaluator,
-    SafeUseOfCxxDeclDescriptor desc
-) const {
+ExplicitSafety
+ClangDeclExplicitSafety::evaluate(Evaluator &evaluator,
+                                  CxxDeclExplicitSafetyDescriptor desc) const {
   // FIXME: Somewhat duplicative with importAsUnsafe.
   // FIXME: Also similar to hasPointerInSubobjects
   // FIXME: should probably also subsume IsSafeUseOfCxxDecl
@@ -8545,7 +8765,11 @@ ExplicitSafety ClangDeclExplicitSafety::evaluate(
   // Explicitly safe.
   if (hasSwiftAttribute(decl, "safe"))
     return ExplicitSafety::Safe;
-  
+
+  // Shared references are considered safe.
+  if (desc.isClass)
+    return ExplicitSafety::Safe;
+
   // Enums are always safe.
   if (isa<clang::EnumDecl>(decl))
     return ExplicitSafety::Safe;
@@ -8581,7 +8805,7 @@ ExplicitSafety ClangDeclExplicitSafety::evaluate(
     if (hasUnsafeType(evaluator, field->getType()))
       return ExplicitSafety::Unsafe;
   }
-  
+
   // Okay, call it safe.
   return ExplicitSafety::Safe;
 }
@@ -8590,23 +8814,6 @@ bool ClangDeclExplicitSafety::isCached() const {
   return isa<clang::RecordDecl>(std::get<0>(getStorage()).decl);
 }
 
-void ClangImporter::withSymbolicFeatureEnabled(
-    llvm::function_ref<void(void)> callback) {
-  llvm::SaveAndRestore<bool> oldImportSymbolicCXXDecls(
-      Impl.importSymbolicCXXDecls, true);
-  Impl.nameImporter->enableSymbolicImportFeature(true);
-  auto importedDeclsCopy = Impl.ImportedDecls;
-  Impl.ImportedDecls.clear();
-  callback();
-  Impl.ImportedDecls = std::move(importedDeclsCopy);
-  Impl.nameImporter->enableSymbolicImportFeature(
-      oldImportSymbolicCXXDecls.get());
-}
-
-bool ClangImporter::isSymbolicImportEnabled() const {
-  return Impl.importSymbolicCXXDecls;
-}
-
 const clang::TypedefType *ClangImporter::getTypeDefForCXXCFOptionsDefinition(
     const clang::Decl *candidateDecl) {
 
@@ -8671,7 +8878,7 @@ bool importer::isCxxStdModule(const clang::Module *module) {
 bool importer::isCxxStdModule(StringRef moduleName, bool IsSystem) {
   if (moduleName == "std")
     return true;
-  // In recent libc++ versions the module is split into multiple top-level
+  // In libc++ versions 17-19 the module is split into multiple top-level
   // modules (std_vector, std_utility, etc).
   if (IsSystem && moduleName.starts_with("std_")) {
     if (moduleName == "std_errno_h")
@@ -8681,6 +8888,19 @@ bool importer::isCxxStdModule(StringRef moduleName, bool IsSystem) {
   return false;
 }
 
+ImportPath::Builder ClangImporter::Implementation::getSwiftModulePath(const clang::Module *M) {
+  ImportPath::Builder builder;
+  while (M) {
+    if (!M->isSubModule() && isCxxStdModule(M))
+      builder.push_back(SwiftContext.Id_CxxStdlib);
+    else
+      builder.push_back(SwiftContext.getIdentifier(M->Name));
+    M = M->Parent;
+  }
+  std::reverse(builder.begin(), builder.end());
+  return builder;
+}
+
 std::optional<clang::QualType>
 importer::getCxxReferencePointeeTypeOrNone(const clang::Type *type) {
   if (type->isReferenceType())
@@ -8793,3 +9013,73 @@ bool importer::declIsCxxOnly(const Decl *decl) {
   }
   return false;
 }
+
+bool importer::isClangNamespace(const DeclContext *dc) {
+  if (const auto *ed = dc->getSelfEnumDecl())
+    return isa_and_nonnull<clang::NamespaceDecl>(ed->getClangDecl());
+
+  return false;
+}
+
+bool importer::isSymbolicCircularBase(const clang::CXXRecordDecl *symbolicClass,
+                                      const clang::RecordDecl *base) {
+  auto *classTemplate = symbolicClass->getDescribedClassTemplate();
+  if (!classTemplate)
+    return false;
+
+  auto *specializedBase =
+      dyn_cast<clang::ClassTemplateSpecializationDecl>(base);
+  if (!specializedBase)
+    return false;
+
+  return classTemplate->getCanonicalDecl() ==
+         specializedBase->getSpecializedTemplate()->getCanonicalDecl();
+}
+
+std::optional<ResultConvention>
+swift::importer::getCxxRefConventionWithAttrs(const clang::Decl *decl) {
+  using RC = ResultConvention;
+
+  if (auto result =
+          matchSwiftAttr<RC>(decl, {{"returns_unretained", RC::Unowned},
+                                    {"returns_retained", RC::Owned}}))
+    return result;
+
+  const clang::Type *returnTy = nullptr;
+  if (const auto *func = llvm::dyn_cast<clang::FunctionDecl>(decl))
+    returnTy = func->getReturnType().getTypePtrOrNull();
+  else if (const auto *method = llvm::dyn_cast<clang::ObjCMethodDecl>(decl))
+    returnTy = method->getReturnType().getTypePtrOrNull();
+
+  if (!returnTy)
+    return std::nullopt;
+
+  const clang::Type *desugaredReturnTy =
+      returnTy->getUnqualifiedDesugaredType();
+
+  if (const auto *ptrType =
+          llvm::dyn_cast<clang::PointerType>(desugaredReturnTy)) {
+    if (const clang::RecordDecl *record =
+            ptrType->getPointeeType()->getAsRecordDecl()) {
+      return matchSwiftAttrConsideringInheritance<RC>(
+          record, {{"returned_as_unretained_by_default", RC::Unowned}});
+    }
+  }
+
+  return std::nullopt;
+}
+
+NominalType *swift::stripInlineNamespaces(NominalType *outer,
+                                          NominalType *inner) {
+  if (!outer || !inner || inner == outer)
+    return nullptr;
+  auto CDInner = inner->getDecl()->getClangDecl();
+  while (inner && isa_and_nonnull<clang::NamespaceDecl>(CDInner) &&
+         cast<clang::NamespaceDecl>(CDInner)->isInline() &&
+         inner->getCanonicalType() != outer->getCanonicalType()) {
+    CDInner = cast<clang::Decl>(CDInner->getDeclContext());
+    inner = dyn_cast<NominalType>(inner->getParent().getPointer());
+  }
+
+  return inner;
+}
diff --git a/lib/ClangImporter/ClangIncludePaths.cpp b/lib/ClangImporter/ClangIncludePaths.cpp
index d2185fd152ded..f8289e1e8e17e 100644
--- a/lib/ClangImporter/ClangIncludePaths.cpp
+++ b/lib/ClangImporter/ClangIncludePaths.cpp
@@ -127,9 +127,13 @@ std::pair<clang::driver::Driver,
 ClangImporter::createClangDriver(
     const LangOptions &LangOpts, const ClangImporterOptions &ClangImporterOpts,
     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> vfs) {
+
+  auto diagVFS = vfs ? vfs : llvm::vfs::getRealFileSystem();
+
+  clang::DiagnosticOptions diagOpts;
   auto *silentDiagConsumer = new clang::DiagnosticConsumer();
   auto clangDiags = clang::CompilerInstance::createDiagnostics(
-      new clang::DiagnosticOptions(), silentDiagConsumer);
+      *diagVFS, diagOpts, silentDiagConsumer);
   clang::driver::Driver clangDriver(ClangImporterOpts.clangPath,
                                     LangOpts.Target.str(), *clangDiags,
                                     "clang LLVM compiler", vfs);
@@ -197,7 +201,7 @@ ClangImporter::createClangArgs(const ClangImporterOptions &ClangImporterOpts,
 }
 
 static SmallVector<std::pair<std::string, std::string>, 2>
-getLibcFileMapping(ASTContext &ctx, StringRef modulemapFileName,
+getLibcFileMapping(const ASTContext &ctx, StringRef modulemapFileName,
                    std::optional<ArrayRef<StringRef>> maybeHeaderFileNames,
                    const llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &vfs,
                    bool suppressDiagnostic) {
@@ -263,7 +267,7 @@ getLibcFileMapping(ASTContext &ctx, StringRef modulemapFileName,
 }
 
 static void getLibStdCxxFileMapping(
-    ClangInvocationFileMapping &fileMapping, ASTContext &ctx,
+    ClangInvocationFileMapping &fileMapping, const ASTContext &ctx,
     const llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &vfs,
     bool suppressDiagnostic) {
   assert(ctx.LangOpts.EnableCXXInterop &&
@@ -412,7 +416,21 @@ static void getLibStdCxxFileMapping(
       "bits/unique_lock.h", "bits/unique_ptr.h", "bits/unordered_map.h",
       "bits/unordered_set.h", "bits/uses_allocator.h",
       "bits/uses_allocator_args.h", "bits/valarray_after.h",
-      "bits/valarray_array.h", "bits/valarray_before.h"};
+      "bits/valarray_array.h", "bits/valarray_before.h", "bits/version.h",
+      // C++20 and newer:
+      "barrier",
+      "compare",
+      "concepts",
+      "format",
+      "latch",
+      "numbers",
+      "ranges",
+      "semaphore",
+      "source_location",
+      "span",
+      "stop_token",
+      "syncstream",
+    };
   std::string additionalHeaderDirectives;
   llvm::raw_string_ostream os(additionalHeaderDirectives);
   os << contents.substr(0, headerInjectionPoint);
@@ -454,7 +472,7 @@ GetPlatformAuxiliaryFile(StringRef Platform, StringRef File,
 }
 
 void GetWindowsFileMappings(
-    ClangInvocationFileMapping &fileMapping, ASTContext &Context,
+    ClangInvocationFileMapping &fileMapping, const ASTContext &Context,
     const llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &driverVFS,
     bool &requiresBuiltinHeadersInSystemModules) {
   const llvm::Triple &Triple = Context.LangOpts.Target;
@@ -482,14 +500,23 @@ void GetWindowsFileMappings(
                              WindowsSDK.Path, WindowsSDK.MajorVersion,
                              WindowsSDK.IncludeVersion,
                              WindowsSDK.LibraryVersion)) {
+    assert(WindowsSDK.MajorVersion > 8);
     llvm::SmallString<261> WinSDKInjection{WindowsSDK.Path};
     llvm::sys::path::append(WinSDKInjection, "Include");
-    if (WindowsSDK.MajorVersion > 8)
-      llvm::sys::path::append(WinSDKInjection, WindowsSDK.IncludeVersion, "um");
+    llvm::sys::path::append(WinSDKInjection, WindowsSDK.IncludeVersion, "um");
     llvm::sys::path::append(WinSDKInjection, "module.modulemap");
 
-    AuxiliaryFile =
-        GetPlatformAuxiliaryFile("windows", "winsdk.modulemap", SearchPathOpts);
+    AuxiliaryFile = GetPlatformAuxiliaryFile("windows", "winsdk_um.modulemap",
+                                             SearchPathOpts);
+    if (!AuxiliaryFile.empty())
+      fileMapping.redirectedFiles.emplace_back(std::string(WinSDKInjection),
+                                               AuxiliaryFile);
+
+    llvm::sys::path::remove_filename(WinSDKInjection);
+    llvm::sys::path::remove_filename(WinSDKInjection);
+    llvm::sys::path::append(WinSDKInjection, "shared", "module.modulemap");
+    AuxiliaryFile = GetPlatformAuxiliaryFile(
+        "windows", "winsdk_shared.modulemap", SearchPathOpts);
     if (!AuxiliaryFile.empty())
       fileMapping.redirectedFiles.emplace_back(std::string(WinSDKInjection),
                                                AuxiliaryFile);
@@ -585,7 +612,7 @@ void GetWindowsFileMappings(
 } // namespace
 
 ClangInvocationFileMapping swift::getClangInvocationFileMapping(
-  ASTContext &ctx, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> vfs,
+  const ASTContext &ctx, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> vfs,
   bool suppressDiagnostic) {
   ClangInvocationFileMapping result;
   if (!vfs)
@@ -655,3 +682,52 @@ ClangInvocationFileMapping swift::getClangInvocationFileMapping(
                          result.requiresBuiltinHeadersInSystemModules);
   return result;
 }
+
+ClangInvocationFileMapping swift::applyClangInvocationMapping(const ASTContext &ctx,
+                                        llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> baseVFS,
+                                        llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &fileSystem,
+                                        bool suppressDiagnostics) {
+  if (ctx.CASOpts.HasImmutableFileSystem)
+    return ClangInvocationFileMapping();
+
+  ClangInvocationFileMapping fileMapping =
+    getClangInvocationFileMapping(ctx, baseVFS, suppressDiagnostics);
+
+  auto importerOpts = ctx.ClangImporterOpts;
+  // Wrap Swift's FS to allow Clang to override the working directory
+  fileSystem = llvm::vfs::RedirectingFileSystem::create(
+      fileMapping.redirectedFiles, true, *fileSystem);
+  if (importerOpts.DumpClangDiagnostics) {
+    llvm::errs() << "clang importer redirected file mappings:\n";
+    for (const auto &mapping : fileMapping.redirectedFiles) {
+      llvm::errs() << "   mapping real file '" << mapping.second
+                   << "' to virtual file '" << mapping.first << "'\n";
+    }
+    llvm::errs() << "\n";
+  }
+
+  if (!fileMapping.overridenFiles.empty()) {
+    llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> overridenVFS =
+        new llvm::vfs::InMemoryFileSystem();
+    for (const auto &file : fileMapping.overridenFiles) {
+      if (importerOpts.DumpClangDiagnostics) {
+        llvm::errs() << "clang importer overriding file '" << file.first
+                     << "' with the following contents:\n";
+        llvm::errs() << file.second << "\n";
+      }
+      auto contents = ctx.Allocate<char>(file.second.size() + 1);
+      std::copy(file.second.begin(), file.second.end(), contents.begin());
+      // null terminate the buffer.
+      contents[contents.size() - 1] = '\0';
+      overridenVFS->addFile(file.first, 0,
+                            llvm::MemoryBuffer::getMemBuffer(StringRef(
+                                contents.begin(), contents.size() - 1)));
+    }
+    llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> overlayVFS =
+        new llvm::vfs::OverlayFileSystem(fileSystem);
+    fileSystem = overlayVFS;
+    overlayVFS->pushOverlay(overridenVFS);
+  }
+
+  return fileMapping;
+}
diff --git a/lib/ClangImporter/ClangModuleDependencyScanner.cpp b/lib/ClangImporter/ClangModuleDependencyScanner.cpp
index 650473f7e5299..7051051cf29bb 100644
--- a/lib/ClangImporter/ClangModuleDependencyScanner.cpp
+++ b/lib/ClangImporter/ClangModuleDependencyScanner.cpp
@@ -37,68 +37,21 @@ using namespace swift;
 using namespace clang::tooling;
 using namespace clang::tooling::dependencies;
 
-static std::string
-moduleCacheRelativeLookupModuleOutput(const ModuleDeps &MD, ModuleOutputKind MOK,
-                                      const StringRef moduleCachePath,
-                                      const StringRef stableModuleCachePath,
-                                      const StringRef runtimeResourcePath) {
-  llvm::SmallString<128> outputPath(moduleCachePath);
-  if (MD.IsInStableDirectories)
-    outputPath = stableModuleCachePath;
-
-  // FIXME: This is a hack to treat Clang modules defined in the compiler's
-  // own resource directory as stable, when they are not reported as such
-  // by the Clang scanner.
-  if (!runtimeResourcePath.empty() &&
-      hasPrefix(llvm::sys::path::begin(MD.ClangModuleMapFile),
-                llvm::sys::path::end(MD.ClangModuleMapFile),
-                llvm::sys::path::begin(runtimeResourcePath),
-                llvm::sys::path::end(runtimeResourcePath)))
-    outputPath = stableModuleCachePath;
-
-  llvm::sys::path::append(outputPath, MD.ID.ModuleName + "-" + MD.ID.ContextHash);
-  switch (MOK) {
-  case ModuleOutputKind::ModuleFile:
-    llvm::sys::path::replace_extension(
-        outputPath, getExtension(swift::file_types::TY_ClangModuleFile));
-    break;
-  case ModuleOutputKind::DependencyFile:
-    llvm::sys::path::replace_extension(
-        outputPath, getExtension(swift::file_types::TY_Dependencies));
-    break;
-  case ModuleOutputKind::DependencyTargets:
-    return MD.ID.ModuleName + "-" + MD.ID.ContextHash;
-  case ModuleOutputKind::DiagnosticSerializationFile:
-    llvm::sys::path::replace_extension(
-        outputPath, getExtension(swift::file_types::TY_SerializedDiagnostics));
-    break;
-  }
-  return outputPath.str().str();
-}
-
 static void addScannerPrefixMapperInvocationArguments(
     std::vector<std::string> &invocationArgStrs, ASTContext &ctx) {
   for (const auto &arg : ctx.SearchPathOpts.ScannerPrefixMapper) {
-    std::string prefixMapArg = "-fdepscan-prefix-map=" + arg;
-    invocationArgStrs.push_back(prefixMapArg);
+    invocationArgStrs.push_back("-fdepscan-prefix-map");
+    invocationArgStrs.push_back(arg.first);
+    invocationArgStrs.push_back(arg.second);
   }
 }
 
 /// Create the command line for Clang dependency scanning.
 std::vector<std::string> ClangImporter::getClangDepScanningInvocationArguments(
-    ASTContext &ctx, std::optional<StringRef> sourceFileName) {
+    ASTContext &ctx) {
   std::vector<std::string> commandLineArgs = getClangDriverArguments(ctx);
   addScannerPrefixMapperInvocationArguments(commandLineArgs, ctx);
 
-  auto sourceFilePos = std::find(
-      commandLineArgs.begin(), commandLineArgs.end(),
-      "<swift-imported-modules>");
-  assert(sourceFilePos != commandLineArgs.end());
-  if (sourceFileName.has_value())
-    *sourceFilePos = sourceFileName->str();
-  else
-    commandLineArgs.erase(sourceFilePos);
-
   // HACK! Drop the -fmodule-format= argument and the one that
   // precedes it.
   {
@@ -129,202 +82,10 @@ std::vector<std::string> ClangImporter::getClangDepScanningInvocationArguments(
   return commandLineArgs;
 }
 
-static std::unique_ptr<llvm::PrefixMapper>
-getClangPrefixMapper(DependencyScanningTool &clangScanningTool,
-                     ModuleDeps &clangModuleDep,
-                     clang::CompilerInvocation &depsInvocation) {
-  std::unique_ptr<llvm::PrefixMapper> Mapper;
-  if (clangModuleDep.IncludeTreeID) {
-    Mapper = std::make_unique<llvm::PrefixMapper>();
-  } else if (clangModuleDep.CASFileSystemRootID) {
-    assert(clangScanningTool.getCachingFileSystem());
-    Mapper = std::make_unique<llvm::TreePathPrefixMapper>(
-        clangScanningTool.getCachingFileSystem());
-  }
-
-  if (Mapper)
-    DepscanPrefixMapping::configurePrefixMapper(depsInvocation, *Mapper);
-
-  return Mapper;
-}
-
-ModuleDependencyVector ClangImporter::bridgeClangModuleDependencies(
-    clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-    clang::tooling::dependencies::ModuleDepsGraph &clangDependencies,
-    StringRef moduleOutputPath, StringRef stableModuleOutputPath,
-    RemapPathCallback callback) {
-  const auto &ctx = Impl.SwiftContext;
-  ModuleDependencyVector result;
-
-  auto remapPath = [&](StringRef path) {
-    if (callback)
-      return callback(path);
-    return path.str();
-  };
-
-  for (auto &clangModuleDep : clangDependencies) {
-    // File dependencies for this module.
-    std::vector<std::string> fileDeps;
-    clangModuleDep.forEachFileDep(
-        [&fileDeps](StringRef fileDep) { fileDeps.emplace_back(fileDep); });
-
-    std::vector<std::string> swiftArgs;
-    auto addClangArg = [&](Twine arg) {
-      swiftArgs.push_back("-Xcc");
-      swiftArgs.push_back(arg.str());
-    };
-
-    // We are using Swift frontend mode.
-    swiftArgs.push_back("-frontend");
-
-    // Swift frontend action: -emit-pcm
-    swiftArgs.push_back("-emit-pcm");
-    swiftArgs.push_back("-module-name");
-    swiftArgs.push_back(clangModuleDep.ID.ModuleName);
-
-    auto pcmPath = moduleCacheRelativeLookupModuleOutput(
-        clangModuleDep, ModuleOutputKind::ModuleFile, moduleOutputPath,
-        stableModuleOutputPath, ctx.SearchPathOpts.RuntimeResourcePath);
-    swiftArgs.push_back("-o");
-    swiftArgs.push_back(pcmPath);
-
-    // Ensure that the resulting PCM build invocation uses Clang frontend
-    // directly
-    swiftArgs.push_back("-direct-clang-cc1-module-build");
-
-    // Swift frontend option for input file path (Foo.modulemap).
-    swiftArgs.push_back(remapPath(clangModuleDep.ClangModuleMapFile));
-
-    // Handle VFSOverlay. If include tree is used, there is no need for overlay.
-    if (!ctx.ClangImporterOpts.UseClangIncludeTree) {
-      for (auto &overlay : ctx.SearchPathOpts.VFSOverlayFiles) {
-        swiftArgs.push_back("-vfsoverlay");
-        swiftArgs.push_back(remapPath(overlay));
-      }
-    }
-
-    // Add args reported by the scanner.
-
-    // Round-trip clang args to canonicalize and clear the options that swift
-    // compiler doesn't need.
-    clang::CompilerInvocation depsInvocation;
-    clang::DiagnosticsEngine clangDiags(new clang::DiagnosticIDs(),
-                                        new clang::DiagnosticOptions(),
-                                        new clang::IgnoringDiagConsumer());
-
-    llvm::SmallVector<const char*> clangArgs;
-    llvm::for_each(
-        clangModuleDep.getBuildArguments(),
-        [&](const std::string &Arg) { clangArgs.push_back(Arg.c_str()); });
-
-    bool success = clang::CompilerInvocation::CreateFromArgs(
-        depsInvocation, clangArgs, clangDiags);
-    (void)success;
-    assert(success && "clang option from dep scanner round trip failed");
-
-    // Create a prefix mapper that matches clang's configuration.
-    auto Mapper =
-        getClangPrefixMapper(clangScanningTool, clangModuleDep, depsInvocation);
-
-    // Clear the cache key for module. The module key is computed from clang
-    // invocation, not swift invocation.
-    depsInvocation.getFrontendOpts().ModuleCacheKeys.clear();
-    depsInvocation.getFrontendOpts().PathPrefixMappings.clear();
-    depsInvocation.getFrontendOpts().OutputFile.clear();
-
-    // Reset CASOptions since that should be coming from swift.
-    depsInvocation.getCASOpts() = clang::CASOptions();
-    depsInvocation.getFrontendOpts().CASIncludeTreeID.clear();
-
-    // FIXME: workaround for rdar://105684525: find the -ivfsoverlay option
-    // from clang scanner and pass to swift.
-    for (auto overlay : depsInvocation.getHeaderSearchOpts().VFSOverlayFiles) {
-      if (llvm::is_contained(ctx.SearchPathOpts.VFSOverlayFiles, overlay))
-        continue;
-      swiftArgs.push_back("-vfsoverlay");
-      swiftArgs.push_back(overlay);
-    }
-
-    llvm::BumpPtrAllocator allocator;
-    llvm::StringSaver saver(allocator);
-    clangArgs.clear();
-    depsInvocation.generateCC1CommandLine(
-        clangArgs,
-        [&saver](const llvm::Twine &T) { return saver.save(T).data(); });
-
-    llvm::for_each(clangArgs, addClangArg);
-
-    // CASFileSystemRootID.
-    std::string RootID = clangModuleDep.CASFileSystemRootID
-                             ? clangModuleDep.CASFileSystemRootID->toString()
-                             : "";
-
-    std::string IncludeTree =
-        clangModuleDep.IncludeTreeID ? *clangModuleDep.IncludeTreeID : "";
-
-    ctx.CASOpts.enumerateCASConfigurationFlags(
-        [&](StringRef Arg) { swiftArgs.push_back(Arg.str()); });
-
-    if (!RootID.empty()) {
-      swiftArgs.push_back("-no-clang-include-tree");
-      swiftArgs.push_back("-cas-fs");
-      swiftArgs.push_back(RootID);
-    }
-
-    if (!IncludeTree.empty()) {
-      swiftArgs.push_back("-clang-include-tree-root");
-      swiftArgs.push_back(IncludeTree);
-    }
-
-    std::string mappedPCMPath = pcmPath;
-    if (Mapper)
-      Mapper->mapInPlace(mappedPCMPath);
-
-    std::vector<LinkLibrary> LinkLibraries;
-    for (const auto &ll : clangModuleDep.LinkLibraries)
-      LinkLibraries.emplace_back(
-          ll.Library,
-          ll.IsFramework ? LibraryKind::Framework : LibraryKind::Library,
-          /*static=*/false);
-
-    // Module-level dependencies.
-    llvm::StringSet<> alreadyAddedModules;
-    auto dependencies = ModuleDependencyInfo::forClangModule(
-        pcmPath, mappedPCMPath, clangModuleDep.ClangModuleMapFile,
-        clangModuleDep.ID.ContextHash, swiftArgs, fileDeps,
-        LinkLibraries, RootID, IncludeTree, /*module-cache-key*/ "",
-        clangModuleDep.IsSystem);
-
-    std::vector<ModuleDependencyID> directDependencyIDs;
-    for (const auto &moduleName : clangModuleDep.ClangModuleDeps) {
-      // FIXME: This assumes, conservatively, that all Clang module imports
-      // are exported. We need to fix this once the clang scanner gains the appropriate
-      // API to query this.
-      dependencies.addModuleImport(moduleName.ModuleName, /* isExported */ true, &alreadyAddedModules);
-      // It is safe to assume that all dependencies of a Clang module are Clang modules.
-      directDependencyIDs.push_back({moduleName.ModuleName, ModuleDependencyKind::Clang});
-    }
-    dependencies.setImportedClangDependencies(directDependencyIDs);
-    result.push_back(std::make_pair(ModuleDependencyID{clangModuleDep.ID.ModuleName,
-                                                       ModuleDependencyKind::Clang},
-                                    dependencies));
-  }
-  return result;
-}
-
-void ClangImporter::recordBridgingHeaderOptions(
-    ModuleDependencyInfo &MDI,
-    const clang::tooling::dependencies::TranslationUnitDeps &deps) {
-  std::vector<std::string> swiftArgs;
-  getBridgingHeaderOptions(deps, swiftArgs);
-  MDI.updateBridgingHeaderCommandLine(swiftArgs);
-}
-
 void ClangImporter::getBridgingHeaderOptions(
+    const ASTContext &ctx,
     const clang::tooling::dependencies::TranslationUnitDeps &deps,
     std::vector<std::string> &swiftArgs) {
-  auto &ctx = Impl.SwiftContext;
-
   auto addClangArg = [&](Twine arg) {
     swiftArgs.push_back("-Xcc");
     swiftArgs.push_back(arg.str());
@@ -345,8 +106,8 @@ void ClangImporter::getBridgingHeaderOptions(
   // Round-trip clang args to canonicalize and clear the options that swift
   // compiler doesn't need.
   clang::CompilerInvocation depsInvocation;
-  clang::DiagnosticsEngine clangDiags(new clang::DiagnosticIDs(),
-                                      new clang::DiagnosticOptions(),
+  clang::DiagnosticOptions diagOpts;
+  clang::DiagnosticsEngine clangDiags(new clang::DiagnosticIDs(), diagOpts,
                                       new clang::IgnoringDiagConsumer());
 
   llvm::SmallVector<const char *> clangArgs;
@@ -383,172 +144,4 @@ void ClangImporter::getBridgingHeaderOptions(
     swiftArgs.push_back("-clang-include-tree-root");
     swiftArgs.push_back(*Tree);
   }
-  if (auto CASFS = deps.CASFileSystemRootID) {
-    swiftArgs.push_back("-no-clang-include-tree");
-    swiftArgs.push_back("-cas-fs");
-    swiftArgs.push_back(*CASFS);
-  }
-}
-
-// The Swift compiler does not have a concept of a working directory.
-// It is instead handled by the Swift driver by resolving relative paths
-// according to the driver's notion of a working directory. On the other hand,
-// Clang does have a concept working directory which may be specified on this
-// Clang invocation with '-working-directory'. If so, it is crucial that we
-// use this directory as an argument to the Clang scanner invocation below.
-static std::optional<std::string>
-computeClangWorkingDirectory(const std::vector<std::string> &commandLineArgs,
-                             const ASTContext &ctx) {
-  std::string workingDir;
-  auto clangWorkingDirPos = std::find(
-      commandLineArgs.rbegin(), commandLineArgs.rend(), "-working-directory");
-  if (clangWorkingDirPos == commandLineArgs.rend())
-    workingDir =
-        ctx.SourceMgr.getFileSystem()->getCurrentWorkingDirectory().get();
-  else {
-    if (clangWorkingDirPos - 1 == commandLineArgs.rend()) {
-      ctx.Diags.diagnose(SourceLoc(), diag::clang_dependency_scan_error,
-                         "Missing '-working-directory' argument");
-      return std::nullopt;
-    }
-    workingDir = *(clangWorkingDirPos - 1);
-  }
-  return workingDir;
-}
-
-ModuleDependencyVector
-ClangImporter::getModuleDependencies(Identifier moduleName,
-                                     StringRef moduleOutputPath,
-                                     StringRef sdkModuleOutputPath,
-                                     const llvm::DenseSet<clang::tooling::dependencies::ModuleID> &alreadySeenClangModules,
-                                     clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-                                     InterfaceSubContextDelegate &delegate,
-                                     llvm::PrefixMapper *mapper,
-                                     bool isTestableImport) {
-  auto &ctx = Impl.SwiftContext;
-  // Determine the command-line arguments for dependency scanning.
-  std::vector<std::string> commandLineArgs =
-      getClangDepScanningInvocationArguments(ctx);
-  auto optionalWorkingDir = computeClangWorkingDirectory(commandLineArgs, ctx);
-  if (!optionalWorkingDir) {
-    ctx.Diags.diagnose(SourceLoc(), diag::clang_dependency_scan_error,
-                       "Missing '-working-directory' argument");
-    return {};
-  }
-  std::string workingDir = *optionalWorkingDir;
-  auto lookupModuleOutput =
-      [moduleOutputPath, sdkModuleOutputPath, &ctx]
-      (const ModuleDeps &MD, ModuleOutputKind MOK) -> std::string {
-    return moduleCacheRelativeLookupModuleOutput(MD, MOK, moduleOutputPath,
-                                                 sdkModuleOutputPath,
-                                                 ctx.SearchPathOpts.RuntimeResourcePath);
-  };
-
-  auto clangModuleDependencies =
-      clangScanningTool.getModuleDependencies(
-          moduleName.str(), commandLineArgs, workingDir,
-          alreadySeenClangModules, lookupModuleOutput);
-  if (!clangModuleDependencies) {
-    auto errorStr = toString(clangModuleDependencies.takeError());
-    // We ignore the "module 'foo' not found" error, the Swift dependency
-    // scanner will report such an error only if all of the module loaders
-    // fail as well.
-    if (errorStr.find("fatal error: module '" + moduleName.str().str() +
-                      "' not found") == std::string::npos)
-      ctx.Diags.diagnose(SourceLoc(), diag::clang_dependency_scan_error,
-                         errorStr);
-    return {};
-  }
-
-  return bridgeClangModuleDependencies(clangScanningTool,
-                                       *clangModuleDependencies,
-                                       moduleOutputPath, sdkModuleOutputPath,
-                                       [&](StringRef path) {
-                                         if (mapper)
-                                           return mapper->mapToString(path);
-                                         return path.str();
-                                       });
-}
-
-bool ClangImporter::getHeaderDependencies(
-    ModuleDependencyID moduleID, std::optional<StringRef> headerPath,
-    std::optional<llvm::MemoryBufferRef> sourceBuffer,
-    clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-    ModuleDependenciesCache &cache,
-    ModuleDependencyIDSetVector &headerClangModuleDependencies,
-    std::vector<std::string> &headerFileInputs,
-    std::vector<std::string> &bridgingHeaderCommandLine,
-    std::optional<std::string> &includeTreeID) {
-  // Scan the specified textual header file and collect its dependencies
-  auto scanHeaderDependencies = [&]() -> llvm::Expected<TranslationUnitDeps> {
-    auto &ctx = Impl.SwiftContext;
-    std::vector<std::string> commandLineArgs =
-        getClangDepScanningInvocationArguments(ctx, headerPath);
-    auto optionalWorkingDir =
-        computeClangWorkingDirectory(commandLineArgs, ctx);
-    if (!optionalWorkingDir) {
-      ctx.Diags.diagnose(SourceLoc(), diag::clang_dependency_scan_error,
-                         "Missing '-working-directory' argument");
-      return llvm::errorCodeToError(
-          std::error_code(errno, std::generic_category()));
-    }
-    std::string workingDir = *optionalWorkingDir;
-    auto moduleOutputPath = cache.getModuleOutputPath();
-    auto sdkModuleOutputPath = cache.getSDKModuleOutputPath();
-    auto lookupModuleOutput =
-        [moduleOutputPath, sdkModuleOutputPath, &ctx]
-        (const ModuleDeps &MD, ModuleOutputKind MOK) -> std::string {
-      return moduleCacheRelativeLookupModuleOutput(MD, MOK,
-                                                   moduleOutputPath,
-                                                   sdkModuleOutputPath,
-                                                   ctx.SearchPathOpts.RuntimeResourcePath);
-    };
-    auto dependencies = clangScanningTool.getTranslationUnitDependencies(
-        commandLineArgs, workingDir, cache.getAlreadySeenClangModules(),
-        lookupModuleOutput, sourceBuffer);
-    if (!dependencies)
-      return dependencies.takeError();
-
-    // Record module dependencies for each new module we found.
-    auto bridgedDeps = bridgeClangModuleDependencies(
-        clangScanningTool, dependencies->ModuleGraph,
-        moduleOutputPath, sdkModuleOutputPath,
-        [&cache](StringRef path) {
-          return cache.getScanService().remapPath(path);
-        });
-    cache.recordDependencies(bridgedDeps);
-
-    llvm::copy(dependencies->FileDeps, std::back_inserter(headerFileInputs));
-    auto bridgedDependencyIDs =
-        llvm::map_range(dependencies->ClangModuleDeps, [](auto &input) {
-          return ModuleDependencyID{input.ModuleName, ModuleDependencyKind::Clang};
-        });
-    headerClangModuleDependencies.insert(bridgedDependencyIDs.begin(),
-                                         bridgedDependencyIDs.end());
-    return dependencies;
-  };
-
-  // - If a generated header is provided, scan the generated header.
-  // - Textual module dependencies require us to process their bridging header.
-  // - Binary module dependnecies may have arbitrary header inputs.
-  auto clangModuleDependencies = scanHeaderDependencies();
-  if (!clangModuleDependencies) {
-    // FIXME: Route this to a normal diagnostic.
-    llvm::logAllUnhandledErrors(clangModuleDependencies.takeError(),
-                                llvm::errs());
-    Impl.SwiftContext.Diags.diagnose(
-        SourceLoc(), diag::clang_dependency_scan_error,
-        "failed to scan bridging header dependencies");
-    return true;
-  }
-
-  auto targetModuleInfo = cache.findKnownDependency(moduleID);
-  if (!targetModuleInfo.isTextualSwiftModule())
-    return false;
-
-  if (auto TreeID = clangModuleDependencies->IncludeTreeID)
-    includeTreeID = TreeID;
-  getBridgingHeaderOptions(*clangModuleDependencies, bridgingHeaderCommandLine);
-
-  return false;
 }
diff --git a/lib/ClangImporter/ImportDecl.cpp b/lib/ClangImporter/ImportDecl.cpp
index 6bd63bda9938f..f2db92c2f1100 100644
--- a/lib/ClangImporter/ImportDecl.cpp
+++ b/lib/ClangImporter/ImportDecl.cpp
@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "CFTypeInfo.h"
+#include "CXXMethodBridging.h"
 #include "ClangDerivedConformances.h"
 #include "ImporterImpl.h"
 #include "SwiftDeclSynthesizer.h"
@@ -26,6 +27,7 @@
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/DiagnosticsClangImporter.h"
+#include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/ExistentialLayout.h"
 #include "swift/AST/Expr.h"
 #include "swift/AST/GenericEnvironment.h"
@@ -46,35 +48,43 @@
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Basic/SourceLoc.h"
+#include "swift/Basic/SourceManager.h"
 #include "swift/Basic/Statistic.h"
 #include "swift/Basic/StringExtras.h"
 #include "swift/Basic/Version.h"
-#include "swift/ClangImporter/CXXMethodBridging.h"
 #include "swift/ClangImporter/ClangImporter.h"
 #include "swift/ClangImporter/ClangImporterRequests.h"
 #include "swift/ClangImporter/ClangModule.h"
 #include "swift/Parse/Lexer.h"
+#include "swift/Parse/ParseDeclName.h"
 #include "swift/Strings.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Attr.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjCCommon.h"
+#include "clang/AST/Expr.h"
 #include "clang/AST/PrettyPrinter.h"
+#include "clang/AST/RecordLayout.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/AST/StmtVisitor.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/Specifiers.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/Lookup.h"
+#include "clang/Sema/SemaDiagnostic.h"
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallBitVector.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/TinyPtrVector.h"
+#include "llvm/Support/Casting.h"
 #include "llvm/Support/Path.h"
 
 #include <algorithm>
@@ -131,7 +141,6 @@ createFuncOrAccessor(ClangImporter::Implementation &impl, SourceLoc funcLoc,
                                     genericParams, dc, clangNode);
   }
   impl.importSwiftAttrAttributes(decl);
-  impl.swiftify(decl);
 
   return decl;
 }
@@ -163,10 +172,6 @@ void ClangImporter::Implementation::makeComputed(AbstractStorageDecl *storage,
 bool importer::recordHasReferenceSemantics(
     const clang::RecordDecl *decl,
     ClangImporter::Implementation *importerImpl) {
-  if (!isa<clang::CXXRecordDecl>(decl) &&
-      !importerImpl->SwiftContext.LangOpts.CForeignReferenceTypes)
-    return false;
-
   // At this point decl might not be fully imported into Swift yet, which
   // means we might not have asked Clang to generate its implicit members, such
   // as copy or move constructors. This would cause CxxRecordSemanticsRequest to
@@ -189,6 +194,22 @@ bool importer::hasImmortalAttrs(const clang::RecordDecl *decl) {
          });
 }
 
+importer::ReturnOwnershipInfo::ReturnOwnershipInfo(
+    const clang::NamedDecl *decl) {
+  if (!decl->hasAttrs())
+    return;
+
+  for (const auto *attr : decl->getAttrs()) {
+    if (const auto *swiftAttr = llvm::dyn_cast<clang::SwiftAttrAttr>(attr)) {
+      if (swiftAttr->getAttribute() == "returns_unretained") {
+        hasReturnsUnretained = true;
+      } else if (swiftAttr->getAttribute() == "returns_retained") {
+        hasReturnsRetained = true;
+      }
+    }
+  }
+}
+
 #ifndef NDEBUG
 static bool verifyNameMapping(MappedTypeNameKind NameMapping,
                               StringRef left, StringRef right) {
@@ -378,6 +399,7 @@ getSwiftStdlibType(const clang::TypedefNameDecl *D,
       case clang::TargetInfo::PNaClABIBuiltinVaList:
       case clang::TargetInfo::SystemZBuiltinVaList:
       case clang::TargetInfo::X86_64ABIBuiltinVaList:
+      case clang::TargetInfo::XtensaABIBuiltinVaList:
         return std::make_pair(Type(), "");
     }
     break;
@@ -842,32 +864,11 @@ static bool isPrintLikeMethod(DeclName name, const DeclContext *dc) {
 using MirroredMethodEntry =
   std::tuple<const clang::ObjCMethodDecl*, ProtocolDecl*, bool /*isAsync*/>;
 
-ImportedType findOptionSetType(clang::QualType type,
-                               ClangImporter::Implementation &Impl) {
-  ImportedType importedType;
-  auto fieldType = type;
-  if (auto elaborated = dyn_cast<clang::ElaboratedType>(fieldType))
-    fieldType = elaborated->desugar();
-  if (auto typedefType = dyn_cast<clang::TypedefType>(fieldType)) {
-    if (Impl.isUnavailableInSwift(typedefType->getDecl())) {
-      if (auto clangEnum =
-              findAnonymousEnumForTypedef(Impl.SwiftContext, typedefType)) {
-        // If this fails, it means that we need a stronger predicate for
-        // determining the relationship between an enum and typedef.
-        assert(
-            clangEnum.value()->getIntegerType()->getCanonicalTypeInternal() ==
-            typedefType->getCanonicalTypeInternal());
-        if (auto swiftEnum = Impl.importDecl(*clangEnum, Impl.CurrentVersion)) {
-          importedType = {cast<TypeDecl>(swiftEnum)->getDeclaredInterfaceType(),
-                          false};
-        }
-      }
-    }
-  }
-  return importedType;
-}
-
 static bool areRecordFieldsComplete(const clang::CXXRecordDecl *decl) {
+  // If the type is incomplete, then the fields are not complete.
+  if (!decl->isCompleteDefinition())
+    return false;
+
   for (const auto *f : decl->fields()) {
     auto *fieldRecord = f->getType()->getAsCXXRecordDecl();
     if (fieldRecord) {
@@ -1193,7 +1194,8 @@ namespace {
       auto *enumDecl = Impl.createDeclWithClangNode<EnumDecl>(
           decl, AccessLevel::Public, Impl.importSourceLoc(decl->getBeginLoc()),
           importedName.getBaseIdentifier(Impl.SwiftContext),
-          Impl.importSourceLoc(decl->getLocation()), std::nullopt, nullptr, dc);
+          Impl.importSourceLoc(decl->getLocation()), ArrayRef<InheritedEntry>(),
+          nullptr, dc);
       // TODO: we only have this for the sid effect of calling
       // "FirstDeclAndLazyMembers.setInt(true)".
       // This should never actually try to use Impl as the member loader,
@@ -1496,6 +1498,24 @@ namespace {
         // bridging, i.e. if the imported typealias should name a bridged type
         // or the original C type.
         clang::QualType ClangType = Decl->getUnderlyingType();
+
+        // Prevent import of typedefs to forward-declared explicit template
+        // specializations, which would trigger assertion in Clang.
+        if (auto *templateSpec = dyn_cast<clang::TemplateSpecializationType>(
+                importer::desugarIfElaborated(ClangType).getTypePtr())) {
+          if (auto *recordType =
+                  templateSpec->desugar()->getAs<clang::RecordType>()) {
+            if (auto *spec = dyn_cast<clang::ClassTemplateSpecializationDecl>(
+                    recordType->getDecl())) {
+              if (spec->getSpecializationKind() ==
+                      clang::TSK_ExplicitSpecialization &&
+                  !spec->isCompleteDefinition()) {
+                return nullptr;
+              }
+            }
+          }
+        }
+
         SwiftType = Impl.importTypeIgnoreIUO(
             ClangType, ImportTypeKind::Typedef,
             ImportDiagnosticAdder(Impl, Decl, Decl->getLocation()),
@@ -1617,7 +1637,8 @@ namespace {
         auto access = importer::convertClangAccess(decl->getAccess());
         auto Loc = Impl.importSourceLoc(decl->getLocation());
         auto structDecl = Impl.createDeclWithClangNode<StructDecl>(
-            decl, access, Loc, name, Loc, std::nullopt, nullptr, dc);
+            decl, access, Loc, name, Loc, ArrayRef<InheritedEntry>(), nullptr,
+            dc);
 
         auto options = getDefaultMakeStructRawValuedOptions();
         options |= MakeStructRawValuedFlags::MakeUnlabeledValueInit;
@@ -1671,7 +1692,7 @@ namespace {
               "NSError enums shouldn't be defined as non-public C++ members");
           // Create the wrapper struct.
           errorWrapper =
-              new (C) StructDecl(loc, name, loc, std::nullopt, nullptr, dc);
+              new (C) StructDecl(loc, name, loc, /*Inherited*/ {}, nullptr, dc);
           SourceLoc end = Impl.importSourceLoc(decl->getEndLoc());
           errorWrapper->setBraces(SourceRange(loc, end));
           errorWrapper->setAccess(AccessLevel::Public);
@@ -1741,8 +1762,8 @@ namespace {
         // Create the enumeration.
         auto enumDecl = Impl.createDeclWithClangNode<EnumDecl>(
             decl, importer::convertClangAccess(decl->getAccess()), loc,
-            enumName, Impl.importSourceLoc(decl->getLocation()), std::nullopt,
-            nullptr, enumDC);
+            enumName, Impl.importSourceLoc(decl->getLocation()),
+            ArrayRef<InheritedEntry>(), nullptr, enumDC);
         enumDecl->setHasFixedRawValues();
 
         // Annotate as 'frozen' if appropriate.
@@ -1864,10 +1885,28 @@ namespace {
         break;
       }
 
+      /// A table mapping each raw value used in this enum to the clang or
+      /// Swift decl for the "canonical" constant corresponding to that raw
+      /// value. The clang decls represent cases that haven't yet been imported;
+      /// the Swift decls represent cases that have been imported before.
+      ///
+      /// The problem we are trying to solve here is that C allows several
+      /// constants in the same enum to have the same raw value, but Swift does
+      /// not. We must therefore resolve collisions by selecting one case to be
+      /// the "canonical" one that will be imported as an \c EnumElementDecl
+      /// and importing the others as static \c VarDecl aliases of it. This
+      /// map knows which constants are canonical and can map a constant's raw
+      /// value to its corresponding canonical constant.
+      ///
+      /// Note that unavailable constants don't get inserted into this table,
+      /// so if an unavailable constant has no available alias, it simply won't
+      /// be present here. (Potential raw value conflicts doesn't really matter
+      /// for them because they will be imported as unavailable anyway.)
       llvm::SmallDenseMap<llvm::APSInt,
                           PointerUnion<const clang::EnumConstantDecl *,
                                        EnumElementDecl *>, 8> canonicalEnumConstants;
 
+      // Fill in `canonicalEnumConstants` if it will be used.
       if (enumKind == EnumKind::NonFrozenEnum ||
           enumKind == EnumKind::FrozenEnum) {
         for (auto constant : decl->enumerators()) {
@@ -1942,24 +1981,32 @@ namespace {
                 SwiftDeclConverter(Impl, getActiveSwiftVersion())
                     .importEnumCase(constant, decl, cast<EnumDecl>(result));
           } else {
-            const clang::EnumConstantDecl *unimported =
+            // Will initially be nullptr if `canonicalCaseIter` points to a
+            // memoized result.
+            const clang::EnumConstantDecl *canonConstant =
                 canonicalCaseIter->
                   second.dyn_cast<const clang::EnumConstantDecl *>();
 
-            // Import the canonical enumerator for this case first.
-            if (unimported) {
+            // First, either import the canonical constant for this case,
+            // or extract the memoized result of a previous import (and use it
+            // to populate `canonConstant`).
+            if (canonConstant) {
               enumeratorDecl = SwiftDeclConverter(Impl, getActiveSwiftVersion())
-                  .importEnumCase(unimported, decl, cast<EnumDecl>(result));
+                  .importEnumCase(canonConstant, decl, cast<EnumDecl>(result));
               if (enumeratorDecl) {
+                // Memoize so we end up in the `else` branch next time.
                 canonicalCaseIter->getSecond() =
                     cast<EnumElementDecl>(enumeratorDecl);
               }
             } else {
               enumeratorDecl =
-                  canonicalCaseIter->second.get<EnumElementDecl *>();
+                  cast<EnumElementDecl *>(canonicalCaseIter->second);
+              canonConstant =
+                  cast<clang::EnumConstantDecl>(enumeratorDecl->getClangDecl());
             }
 
-            if (unimported != constant && enumeratorDecl) {
+            // If `constant` wasn't the `canonConstant`, import it as an alias.
+            if (canonConstant != constant && enumeratorDecl) {
               ImportedName importedName =
                   Impl.importFullName(constant, getActiveSwiftVersion());
               Identifier name = importedName.getBaseIdentifier(Impl.SwiftContext);
@@ -1975,6 +2022,7 @@ namespace {
             }
           }
 
+          // Now import each of the constant's alternate names.
           Impl.forEachDistinctName(constant,
                                    [&](ImportedName newName,
                                        ImportNameVersion nameVersion) -> bool {
@@ -2025,6 +2073,19 @@ namespace {
         }
       }
 
+      // We don't always add an imported canonical constant to the enum's
+      // members right away, but we should have by the time we leave the loop.
+      // Verify that they are all in the enum's member list. (rdar://148213237)
+      if (CONDITIONAL_ASSERT_enabled()) {
+        for (const auto &entry : canonicalEnumConstants) {
+          auto importedCase = entry.second.dyn_cast<EnumElementDecl *>();
+          if (!importedCase)
+            continue;
+
+          ASSERT(llvm::is_contained(result->getCurrentMembers(), importedCase));
+        }
+      }
+
       return result;
     }
 
@@ -2035,8 +2096,8 @@ namespace {
     bool recordHasMoveOnlySemantics(const clang::RecordDecl *decl) {
       auto semanticsKind = evaluateOrDefault(
           Impl.SwiftContext.evaluator,
-          CxxRecordSemantics({decl, Impl.SwiftContext, &Impl}), {});
-      return semanticsKind == CxxRecordSemanticsKind::MoveOnly;
+          CxxValueSemantics({decl->getTypeForDecl(), &Impl}), {});
+      return semanticsKind == CxxValueSemanticsKind::MoveOnly;
     }
 
     void markReturnsUnsafeNonescapable(AbstractFunctionDecl *fd) {
@@ -2081,25 +2142,27 @@ namespace {
       if (decl->isInterface())
         return nullptr;
 
-      if (!decl->getDefinition()) {
+      bool incompleteTypeAsReference = false;
+      if (auto def = decl->getDefinition()) {
+        // Continue with the definition of the type.
+        decl = def;
+      } else if (recordHasReferenceSemantics(decl)) {
+        // Incomplete types are okay if the resulting type has reference
+        // semantics.
+        incompleteTypeAsReference = true;
+      } else {
         Impl.addImportDiagnostic(
             decl,
             Diagnostic(diag::incomplete_record, Impl.SwiftContext.AllocateCopy(
                                                     decl->getNameAsString())),
             decl->getLocation());
-      }
 
-      // FIXME: Figure out how to deal with incomplete types, since that
-      // notion doesn't exist in Swift.
-      decl = decl->getDefinition();
-      if (!decl) {
         forwardDeclaration = true;
         return nullptr;
       }
 
       // TODO(https://github.com/apple/swift/issues/56206): Fix this once we support dependent types.
-      if (decl->getTypeForDecl()->isDependentType() &&
-          !Impl.importSymbolicCXXDecls) {
+      if (decl->getTypeForDecl()->isDependentType()) {
         Impl.addImportDiagnostic(
             decl, Diagnostic(
                       diag::record_is_dependent,
@@ -2109,7 +2172,7 @@ namespace {
       }
 
       // Don't import nominal types that are over-aligned.
-      if (Impl.isOverAligned(decl)) {
+      if (decl->isCompleteDefinition() && Impl.isOverAligned(decl)) {
         Impl.addImportDiagnostic(
             decl, Diagnostic(
                       diag::record_over_aligned,
@@ -2120,6 +2183,9 @@ namespace {
 
       auto isNonTrivialDueToAddressDiversifiedPtrAuth =
           [](const clang::RecordDecl *decl) {
+            if (!decl->isCompleteDefinition())
+              return true;
+
             for (auto *field : decl->fields()) {
               if (!field->getType().isNonTrivialToPrimitiveCopy()) {
                 continue;
@@ -2175,7 +2241,8 @@ namespace {
                                             *correctSwiftName);
 
       auto dc =
-          Impl.importDeclContextOf(decl, importedName.getEffectiveContext());
+          Impl.importDeclContextOf(decl, importedName.getEffectiveContext(),
+                                   incompleteTypeAsReference);
       if (!dc) {
         Impl.addImportDiagnostic(
             decl, Diagnostic(
@@ -2206,7 +2273,7 @@ namespace {
       else
         result = Impl.createDeclWithClangNode<StructDecl>(
             decl, importer::convertClangAccess(decl->getAccess()), loc, name,
-            loc, std::nullopt, nullptr, dc);
+            loc, ArrayRef<InheritedEntry>(), nullptr, dc);
       Impl.ImportedDecls[{decl->getCanonicalDecl(), getVersion()}] = result;
 
       if (recordHasMoveOnlySemantics(decl)) {
@@ -2222,9 +2289,11 @@ namespace {
       // solution would be to turn them into members and add conversion
       // functions.
       if (auto cxxRecordDecl = dyn_cast<clang::CXXRecordDecl>(decl)) {
-        for (auto base : cxxRecordDecl->bases()) {
-          if (auto *baseRecordDecl = base.getType()->getAsCXXRecordDecl()) {
-            Impl.importDecl(baseRecordDecl, getVersion());
+        if (cxxRecordDecl->isCompleteDefinition()) {
+          for (auto base : cxxRecordDecl->bases()) {
+            if (auto *baseRecordDecl = base.getType()->getAsCXXRecordDecl()) {
+              Impl.importDecl(baseRecordDecl, getVersion());
+            }
           }
         }
       }
@@ -2359,7 +2428,34 @@ namespace {
           continue;
         }
 
-        members.push_back(cast<VarDecl>(member));
+        auto *vd = cast<VarDecl>(member);
+        auto getFieldDecl =
+            [](const clang::NamedDecl *decl) -> const clang::FieldDecl * {
+          if (const clang::FieldDecl *fd = dyn_cast<clang::FieldDecl>(decl))
+            return fd;
+          if (const clang::IndirectFieldDecl *ind =
+                  dyn_cast<clang::IndirectFieldDecl>(decl))
+            return ind->getAnonField();
+          return nullptr;
+        };
+
+        if (!isNonEscapable && !decl->isAnonymousStructOrUnion()) {
+          if (const auto *fd = getFieldDecl(nd)) {
+            if (evaluateOrDefault(
+                    Impl.SwiftContext.evaluator,
+                    ClangTypeEscapability({fd->getType().getTypePtr(), &Impl}),
+                    CxxEscapability::Unknown) ==
+                CxxEscapability::NonEscapable) {
+              Impl.addImportDiagnostic(
+                  decl,
+                  Diagnostic(diag::nonescapable_field_of_escapable, decl,
+                             nd->getName()),
+                  decl->getLocation());
+              return nullptr;
+            }
+          }
+        }
+        members.push_back(vd);
       }
 
       bool hasReferenceableFields = !members.empty();
@@ -2416,7 +2512,9 @@ namespace {
 
       const clang::CXXRecordDecl *cxxRecordDecl =
           dyn_cast<clang::CXXRecordDecl>(decl);
-      bool hasBaseClasses = cxxRecordDecl && !cxxRecordDecl->bases().empty();
+      bool hasBaseClasses = cxxRecordDecl &&
+          cxxRecordDecl->isCompleteDefinition() &&
+          !cxxRecordDecl->bases().empty();
       if (hasBaseClasses) {
         hasUnreferenceableStorage = true;
         hasMemberwiseInitializer = false;
@@ -2424,7 +2522,8 @@ namespace {
 
       bool needsEmptyInitializer = true;
       if (cxxRecordDecl) {
-        needsEmptyInitializer = !cxxRecordDecl->isAbstract() &&
+        needsEmptyInitializer = cxxRecordDecl->isCompleteDefinition() &&
+                                !cxxRecordDecl->isAbstract() &&
                                 (!cxxRecordDecl->hasDefaultConstructor() ||
                                  cxxRecordDecl->ctors().empty());
       }
@@ -2468,7 +2567,8 @@ namespace {
       // only when the same is possible in C++. While we could check for that
       // exactly, checking whether the C++ class is an aggregate
       // (C++ [dcl.init.aggr]) has the same effect.
-      bool isAggregate = !cxxRecordDecl || cxxRecordDecl->isAggregate();
+      bool isAggregate = decl->isCompleteDefinition() &&
+          (!cxxRecordDecl || cxxRecordDecl->isAggregate());
       if ((hasReferenceableFields && hasMemberwiseInitializer && isAggregate) ||
           forceMemberwiseInitializer) {
         // The default zero initializer suppresses the implicit value
@@ -2497,8 +2597,8 @@ namespace {
           result->addMember(ctor);
         }
       } else {
-        if (Impl.SwiftContext.LangOpts.hasFeature(
-                Feature::CXXForeignReferenceTypeInitializers)) {
+        if (!Impl.SwiftContext.LangOpts.hasFeature(
+                Feature::SuppressCXXForeignReferenceTypeInitializers)) {
           assert(
               isa<ClassDecl>(result) &&
               "Expected result to be a ClassDecl as it cannot be a StructDecl");
@@ -2516,12 +2616,13 @@ namespace {
                              });
                 });
             if (!hasUserProvidedStaticFactory) {
-              if (auto generatedCxxMethodDecl =
-                      synthesizer.synthesizeStaticFactoryForCXXForeignRef(
-                          cxxRecordDecl)) {
+              auto generatedCxxMethodDecls =
+                  synthesizer.synthesizeStaticFactoryForCXXForeignRef(
+                      cxxRecordDecl);
+              for (auto *methodDecl : generatedCxxMethodDecls) {
                 if (Decl *importedInitDecl =
                         Impl.SwiftContext.getClangModuleLoader()
-                            ->importDeclDirectly(generatedCxxMethodDecl))
+                            ->importDeclDirectly(methodDecl))
                   result->addMember(importedInitDecl);
               }
             }
@@ -2593,22 +2694,23 @@ namespace {
           result->addMember(p);
         }
 
-        for (auto &subscriptInfo : Impl.cxxSubscripts) {
-          auto declAndParameterType = subscriptInfo.first;
-          if (declAndParameterType.first != result)
-            continue;
-
-          auto getterAndSetter = subscriptInfo.second;
-          auto subscript = synthesizer.makeSubscript(getterAndSetter.first,
-                                                     getterAndSetter.second);
-          // Also add subscripts directly because they won't be found from the
-          // clang decl.
-          result->addMember(subscript);
-
-          // Add the subscript as an alternative for the getter so that it gets
-          // carried into derived classes.
-          auto *subscriptImpl = getterAndSetter.first ? getterAndSetter.first : getterAndSetter.second;
-          Impl.addAlternateDecl(subscriptImpl, subscript);
+        auto it = Impl.cxxSubscripts.find(result);
+        if (it != Impl.cxxSubscripts.end()) {
+          for (auto &subscriptInfo : it->second) {
+            auto getterAndSetter = subscriptInfo.second;
+            auto subscript = synthesizer.makeSubscript(getterAndSetter.first,
+                                                       getterAndSetter.second);
+            // Also add subscripts directly because they won't be found from the
+            // clang decl.
+            result->addMember(subscript);
+
+            // Add the subscript as an alternative for the getter so that it
+            // gets carried into derived classes.
+            auto *subscriptImpl = getterAndSetter.first
+                                      ? getterAndSetter.first
+                                      : getterAndSetter.second;
+            Impl.addAlternateDecl(subscriptImpl, subscript);
+          }
         }
 
         auto getterAndSetterIt = Impl.cxxDereferenceOperators.find(result);
@@ -2633,6 +2735,28 @@ namespace {
         }
       }
 
+      if (auto classDecl = dyn_cast<ClassDecl>(result)) {
+        validateForeignReferenceType(decl, classDecl);
+
+        auto availability = Impl.SwiftContext.getSwift58Availability();
+        if (!availability.isAlwaysAvailable()) {
+          assert(availability.hasMinimumVersion());
+          auto AvAttr = AvailableAttr::createPlatformVersioned(
+              Impl.SwiftContext, targetPlatform(Impl.SwiftContext.LangOpts),
+              /*Message=*/"", /*Rename=*/"",
+              availability.getRawMinimumVersion(), /*Deprecated=*/{},
+              /*Obsoleted=*/{});
+          classDecl->getAttrs().add(AvAttr);
+        }
+
+        if (cxxRecordDecl && cxxRecordDecl->isEffectivelyFinal())
+          classDecl->getAttrs().add(new (Impl.SwiftContext)
+                                        FinalAttr(/*IsImplicit=*/true));
+      }
+
+      // If we need it, add an explicit "deinit" to this type.
+      synthesizer.addExplicitDeinitIfRequired(result, decl);
+
       result->setMemberLoader(&Impl, 0);
       return result;
     }
@@ -2675,12 +2799,13 @@ namespace {
       }
     }
 
-    void validateForeignReferenceType(const clang::CXXRecordDecl *decl,
+    void validateForeignReferenceType(const clang::RecordDecl *decl,
                                       ClassDecl *classDecl) {
 
       enum class RetainReleaseOperationKind {
         notAfunction,
-        doesntReturnVoidOrSelf,
+        notAnInstanceFunction,
+        invalidReturnType,
         invalidParameters,
         valid
       };
@@ -2693,35 +2818,62 @@ namespace {
         if (!operationFn)
           return RetainReleaseOperationKind::notAfunction;
 
-        if (operationFn->getParameters()->size() != 1)
-          return RetainReleaseOperationKind::invalidParameters;
+        if (operationFn->isStatic())
+          return RetainReleaseOperationKind::notAnInstanceFunction;
 
-        Type paramType =
-            operationFn->getParameters()->get(0)->getInterfaceType();
-        // Unwrap if paramType is an OptionalType
-        if (Type optionalType = paramType->getOptionalObjectType()) {
-          paramType = optionalType;
-        }
+        if (operationFn->isInstanceMember()) {
+          if (operationFn->getParameters()->size() != 0)
+            return RetainReleaseOperationKind::invalidParameters;
+        } else {
+          if (operationFn->getParameters()->size() != 1)
+            return RetainReleaseOperationKind::invalidParameters;
+        }
+
+        Type paramType;
+        NominalTypeDecl *paramDecl = nullptr;
+        if (!operationFn->isInstanceMember()) {
+          paramType =
+              operationFn->getParameters()->get(0)->getInterfaceType();
+          // Unwrap if paramType is an OptionalType
+          if (Type optionalType = paramType->getOptionalObjectType()) {
+            paramType = optionalType;
+          }
 
-        swift::NominalTypeDecl *paramDecl = paramType->getAnyNominal();
+          paramDecl = paramType->getAnyNominal();
+        } else {
+          paramDecl = cast<NominalTypeDecl>(operationFn->getParent());
+          paramType = paramDecl->getDeclaredInterfaceType();
+        }
 
         // The return type should be void (for release functions), or void
         // or the parameter type (for retain functions).
         auto resultInterfaceType = operationFn->getResultInterfaceType();
-        if (!resultInterfaceType->isVoid()) {
+        if (!resultInterfaceType->isVoid() &&
+            !resultInterfaceType->isUInt() &&
+            !resultInterfaceType->isUInt8() &&
+            !resultInterfaceType->isUInt16() &&
+            !resultInterfaceType->isUInt32() &&
+            !resultInterfaceType->isUInt64() &&
+            !resultInterfaceType->isInt() &&
+            !resultInterfaceType->isInt8() &&
+            !resultInterfaceType->isInt16() &&
+            !resultInterfaceType->isInt32() &&
+            !resultInterfaceType->isInt64()) {
           if (operationKind == CustomRefCountingOperationKind::release ||
               !resultInterfaceType->lookThroughSingleOptionalType()->isEqual(paramType))
-            return RetainReleaseOperationKind::doesntReturnVoidOrSelf;
+            return RetainReleaseOperationKind::invalidReturnType;
         }
 
         // The parameter of the retain/release function should be pointer to the
         // same FRT or a base FRT.
         if (paramDecl != classDecl) {
-          if (const clang::Decl *paramClangDecl = paramDecl->getClangDecl()) {
-            if (const auto *paramTypeDecl =
-                    dyn_cast<clang::CXXRecordDecl>(paramClangDecl)) {
-              if (decl->isDerivedFrom(paramTypeDecl)) {
-                return RetainReleaseOperationKind::valid;
+          if (auto cxxDecl = dyn_cast<clang::CXXRecordDecl>(decl)) {
+            if (const clang::Decl *paramClangDecl = paramDecl->getClangDecl()) {
+              if (const auto *paramTypeDecl =
+                      dyn_cast<clang::CXXRecordDecl>(paramClangDecl)) {
+                if (cxxDecl->isDerivedFrom(paramTypeDecl)) {
+                  return RetainReleaseOperationKind::valid;
+                }
               }
             }
           }
@@ -2776,7 +2928,13 @@ namespace {
               diag::foreign_reference_types_retain_release_not_a_function_decl,
               false, retainOperation.name);
           break;
-        case RetainReleaseOperationKind::doesntReturnVoidOrSelf:
+        case RetainReleaseOperationKind::notAnInstanceFunction:
+          Impl.diagnose(
+              loc,
+              diag::foreign_reference_types_retain_release_not_an_instance_function,
+              false, retainOperation.name);
+          break;
+        case RetainReleaseOperationKind::invalidReturnType:
           Impl.diagnose(
               loc,
               diag::foreign_reference_types_retain_non_void_or_self_return_type,
@@ -2841,7 +2999,13 @@ namespace {
               diag::foreign_reference_types_retain_release_not_a_function_decl,
               true, releaseOperation.name);
           break;
-        case RetainReleaseOperationKind::doesntReturnVoidOrSelf:
+        case RetainReleaseOperationKind::notAnInstanceFunction:
+          Impl.diagnose(
+              loc,
+              diag::foreign_reference_types_retain_release_not_an_instance_function,
+              true, releaseOperation.name);
+          break;
+        case RetainReleaseOperationKind::invalidReturnType:
           Impl.diagnose(
               loc,
               diag::foreign_reference_types_release_non_void_return_type,
@@ -2871,7 +3035,13 @@ namespace {
       if (!Impl.SwiftContext.LangOpts.EnableCXXInterop)
         return VisitRecordDecl(decl);
 
-      if (!decl->getDefinition()) {
+      if (auto def = decl->getDefinition()) {
+        // Continue with the definition of the type.
+        decl = def;
+      } else if (recordHasReferenceSemantics(decl)) {
+        // Incomplete types are okay if the resulting type has reference
+        // semantics.
+      } else {
         Impl.addImportDiagnostic(
             decl,
             Diagnostic(diag::incomplete_record, Impl.SwiftContext.AllocateCopy(
@@ -2887,10 +3057,7 @@ namespace {
             Impl.diagnose(HeaderLoc(attr.second),
                           diag::private_fileid_attr_here);
         }
-      }
 
-      decl = decl->getDefinition();
-      if (!decl) {
         forwardDeclaration = true;
         return nullptr;
       }
@@ -2903,8 +3070,17 @@ namespace {
           decl->getIdentifier() &&
           (decl->getName() == "tzdb" || decl->getName() == "time_zone_link" ||
            decl->getName() == "__compressed_pair" ||
+           decl->getName() == "__optional_copy_assign_base" || // libc++
+           decl->getName() == "__optional_move_assign_base" || // libc++
            decl->getName() == "time_zone"))
         return nullptr;
+      // Bail if this is one of the base types of std::optional. Those types are
+      // mixins that are not designed to be used directly.
+      if (decl->getDeclContext()->isNamespace() && decl->isInStdNamespace() &&
+          decl->getIdentifier() &&
+          (decl->getName() == "_Optional_payload_base" ||
+           decl->getName() == "_Optional_payload"))
+        return nullptr;
 
       auto &clangSema = Impl.getClangSema();
       // Make Clang define any implicit constructors it may need (copy,
@@ -2923,7 +3099,9 @@ namespace {
                             usingShadowDecl)) {
                   auto baseCtorDecl = dyn_cast<clang::CXXConstructorDecl>(
                       ctorUsingShadowDecl->getTargetDecl());
-                  if (!baseCtorDecl || baseCtorDecl->isDeleted())
+                  if (!baseCtorDecl || baseCtorDecl->isDeleted() ||
+                      baseCtorDecl->isCopyConstructor() ||
+                      baseCtorDecl->isMoveConstructor())
                     continue;
                   auto loc = ctorUsingShadowDecl->getLocation();
 
@@ -2945,10 +3123,14 @@ namespace {
             clangSema.DefineImplicitDefaultConstructor(clang::SourceLocation(),
                                                        ctor);
         }
+        // If the C++ struct is annotated as non-copyable, we should not try to
+        // instantiate its copy constructor.
+        bool isExplicitlyNonCopyable = hasNonCopyableAttr(decl);
+
         clang::CXXConstructorDecl *copyCtor = nullptr;
         clang::CXXConstructorDecl *moveCtor = nullptr;
         clang::CXXConstructorDecl *defaultCtor = nullptr;
-        if (decl->needsImplicitCopyConstructor()) {
+        if (decl->needsImplicitCopyConstructor() && !isExplicitlyNonCopyable) {
           copyCtor = clangSema.DeclareImplicitCopyConstructor(
               const_cast<clang::CXXRecordDecl *>(decl));
         }
@@ -2971,7 +3153,7 @@ namespace {
                 // that's what "DefineImplicitCopyConstructor" checks.
                 !declCtor->doesThisDeclarationHaveABody()) {
               if (declCtor->isCopyConstructor()) {
-                if (!copyCtor)
+                if (!copyCtor && !isExplicitlyNonCopyable)
                   copyCtor = declCtor;
               } else if (declCtor->isMoveConstructor()) {
                 if (!moveCtor)
@@ -2983,11 +3165,12 @@ namespace {
             }
           }
         }
-        if (copyCtor) {
+        if (copyCtor && !isExplicitlyNonCopyable &&
+            !decl->isAnonymousStructOrUnion()) {
           clangSema.DefineImplicitCopyConstructor(clang::SourceLocation(),
                                                   copyCtor);
         }
-        if (moveCtor) {
+        if (moveCtor && !decl->isAnonymousStructOrUnion()) {
           clangSema.DefineImplicitMoveConstructor(clang::SourceLocation(),
                                                   moveCtor);
         }
@@ -3005,14 +3188,11 @@ namespace {
 
       // It is important that we bail on an unimportable record *before* we import
       // any of its members or cache the decl.
-      auto semanticsKind = evaluateOrDefault(
+      auto valueSemanticsKind = evaluateOrDefault(
           Impl.SwiftContext.evaluator,
-          CxxRecordSemantics({decl, Impl.SwiftContext, &Impl}), {});
-      if ((semanticsKind == CxxRecordSemanticsKind::MissingLifetimeOperation ||
-           semanticsKind == CxxRecordSemanticsKind::UnavailableConstructors) &&
-          // Let un-specialized class templates through. We'll sort out their
-          // members once they're instantiated.
-          !Impl.importSymbolicCXXDecls) {
+          CxxValueSemantics({decl->getTypeForDecl(), &Impl}), {});
+      if (valueSemanticsKind == CxxValueSemanticsKind::MissingLifetimeOperation ||
+          valueSemanticsKind == CxxValueSemanticsKind::UnavailableConstructors) {
 
         HeaderLoc loc(decl->getLocation());
         if (hasUnsafeAPIAttr(decl))
@@ -3025,7 +3205,7 @@ namespace {
           Impl.diagnose(loc, diag::api_pattern_attr_ignored, "import_iterator",
                         decl->getNameAsString());
 
-        if (semanticsKind == CxxRecordSemanticsKind::UnavailableConstructors) {
+        if (valueSemanticsKind == CxxValueSemanticsKind::UnavailableConstructors) {
           Impl.addImportDiagnostic(
               decl, Diagnostic(diag::record_unsupported_default_args),
               decl->getLocation());
@@ -3039,7 +3219,12 @@ namespace {
             decl->getLocation());
         return nullptr;
       }
-      if (semanticsKind == CxxRecordSemanticsKind::SwiftClassType) {
+
+      auto cxxRecordsemanticsKind = evaluateOrDefault(
+          Impl.SwiftContext.evaluator,
+          CxxRecordSemantics({decl, Impl.SwiftContext, &Impl}), {});
+
+      if (cxxRecordsemanticsKind == CxxRecordSemanticsKind::SwiftClassType) {
         // FIXME: add a diagnostic here for unsupported imported use of Swift
         // type?
         return nullptr;
@@ -3062,25 +3247,6 @@ namespace {
 
       validatePrivateFileIDAttributes(decl);
 
-      if (auto classDecl = dyn_cast<ClassDecl>(result)) {
-        validateForeignReferenceType(decl, classDecl);
-
-        auto availability = Impl.SwiftContext.getSwift58Availability();
-        if (!availability.isAlwaysAvailable()) {
-          assert(availability.hasMinimumVersion());
-          auto AvAttr = AvailableAttr::createPlatformVersioned(
-              Impl.SwiftContext, targetPlatform(Impl.SwiftContext.LangOpts),
-              /*Message=*/"", /*Rename=*/"",
-              availability.getRawMinimumVersion(), /*Deprecated=*/{},
-              /*Obsoleted=*/{});
-          classDecl->getAttrs().add(AvAttr);
-        }
-
-        if (decl->isEffectivelyFinal())
-          classDecl->getAttrs().add(new (Impl.SwiftContext)
-                                    FinalAttr(/*IsImplicit=*/true));
-      }
-
       // If this module is declared as a C++ module, try to synthesize
       // conformances to Swift protocols from the Cxx module.
       auto clangModule = Impl.getClangOwningModule(result->getClangNode());
@@ -3099,82 +3265,9 @@ namespace {
         }
       }
 
-      if (auto *ntd = dyn_cast<NominalTypeDecl>(result))
-        addExplicitProtocolConformances(ntd, decl);
-
       return result;
     }
 
-    void
-    addExplicitProtocolConformances(NominalTypeDecl *decl,
-                                    const clang::CXXRecordDecl *clangDecl) {
-      // Propagate conforms_to attribute from public base classes.
-      for (auto base : clangDecl->bases()) {
-        if (base.getAccessSpecifier() != clang::AccessSpecifier::AS_public)
-          continue;
-        if (auto *baseClangDecl = base.getType()->getAsCXXRecordDecl())
-          addExplicitProtocolConformances(decl, baseClangDecl);
-      }
-
-      if (!clangDecl->hasAttrs())
-        return;
-
-      SmallVector<ValueDecl *, 1> results;
-      auto conformsToAttr =
-          llvm::find_if(clangDecl->getAttrs(), [](auto *attr) {
-            if (auto swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr))
-              return swiftAttr->getAttribute().starts_with("conforms_to:");
-            return false;
-          });
-      if (conformsToAttr == clangDecl->getAttrs().end())
-        return;
-
-      auto conformsToValue = cast<clang::SwiftAttrAttr>(*conformsToAttr)
-                                 ->getAttribute()
-                                 .drop_front(StringRef("conforms_to:").size())
-                                 .str();
-      auto names = StringRef(conformsToValue).split('.');
-      auto moduleName = names.first;
-      auto protocolName = names.second;
-      if (protocolName.empty()) {
-        HeaderLoc attrLoc((*conformsToAttr)->getLocation());
-        Impl.diagnose(attrLoc, diag::conforms_to_missing_dot, conformsToValue);
-        return;
-      }
-
-      auto *mod = Impl.SwiftContext.getModuleByIdentifier(
-          Impl.SwiftContext.getIdentifier(moduleName));
-      if (!mod) {
-        HeaderLoc attrLoc((*conformsToAttr)->getLocation());
-        Impl.diagnose(attrLoc, diag::cannot_find_conforms_to_module,
-                      conformsToValue, moduleName);
-        return;
-      }
-      mod->lookupValue(Impl.SwiftContext.getIdentifier(protocolName),
-                       NLKind::UnqualifiedLookup, results);
-      if (results.empty()) {
-        HeaderLoc attrLoc((*conformsToAttr)->getLocation());
-        Impl.diagnose(attrLoc, diag::cannot_find_conforms_to, protocolName,
-                      moduleName);
-        return;
-      } else if (results.size() != 1) {
-        HeaderLoc attrLoc((*conformsToAttr)->getLocation());
-        Impl.diagnose(attrLoc, diag::conforms_to_ambiguous, protocolName,
-                      moduleName);
-        return;
-      }
-
-      auto result = results.front();
-      if (auto protocol = dyn_cast<ProtocolDecl>(result)) {
-        decl->getAttrs().add(
-            new (Impl.SwiftContext) SynthesizedProtocolAttr(protocol, &Impl, false));
-      } else {
-        HeaderLoc attrLoc((*conformsToAttr)->getLocation());
-        Impl.diagnose(attrLoc, diag::conforms_to_not_protocol,
-                      result->getDescriptiveKind(), result, conformsToValue);
-      }
-    }
-
     bool isSpecializationDepthGreaterThan(
         const clang::ClassTemplateSpecializationDecl *decl, unsigned maxDepth) {
       for (auto arg : decl->getTemplateArgs().asArray()) {
@@ -3193,32 +3286,12 @@ namespace {
 
     Decl *VisitClassTemplateSpecializationDecl(
                  const clang::ClassTemplateSpecializationDecl *decl) {
-      // Treat a specific specialization like the unspecialized class template
-      // when importing it in symbolic mode.
-      if (Impl.importSymbolicCXXDecls)
-        return Impl.importDecl(decl->getSpecializedTemplate(),
-                               Impl.CurrentVersion);
-
-      bool isPair = decl->getSpecializedTemplate()->isInStdNamespace() &&
-                    decl->getSpecializedTemplate()->getName() == "pair";
-
-      // Before we go any further, check if we've already got tens of thousands
-      // of specializations. If so, it means we're likely instantiating a very
-      // deep/complex template, or we've run into an infinite loop. In either
-      // case, its not worth the compile time, so bail.
-      // TODO: this could be configurable at some point.
-      size_t specializationLimit = !isPair ? 1000 : 10000;
-      if (size_t(
-              llvm::size(decl->getSpecializedTemplate()->specializations())) >
-          specializationLimit) {
-        // Note: it would be nice to import a dummy unavailable struct,
-        // but we would then need to instantiate the template here,
-        // as we cannot import a struct without a definition. That would
-        // defeat the purpose. Also, we can't make the dummy
-        // struct simply unavailable, as that still makes the
-        // typelias that references it available.
+      // Importing std::conditional substantially increases compile times when
+      // building with libstdc++, i.e. on most Linux distros.
+      if (decl->isInStdNamespace() && decl->getIdentifier() &&
+          (decl->getName() == "conditional" || decl->getName() == "__or_" ||
+            decl->getName() == "_Expr" || decl->getName() == "__val_expr"))
         return nullptr;
-      }
 
       // `decl->getDefinition()` can return nullptr before the call to sema and
       // return its definition afterwards.
@@ -3228,7 +3301,7 @@ namespace {
             decl->getLocation(),
             const_cast<clang::ClassTemplateSpecializationDecl *>(decl),
             clang::TemplateSpecializationKind::TSK_ImplicitInstantiation,
-            /*Complain*/ false);
+            /*Complain*/ false, /*PrimaryStrictPackMatch*/ false);
         // If the template can't be instantiated, bail.
         if (notInstantiated)
           return nullptr;
@@ -3373,8 +3446,8 @@ namespace {
               decl->getAnonField()->getParent())) {
         auto semanticsKind = evaluateOrDefault(
             Impl.SwiftContext.evaluator,
-            CxxRecordSemantics({parent, Impl.SwiftContext, &Impl}), {});
-        if (semanticsKind == CxxRecordSemanticsKind::MissingLifetimeOperation)
+            CxxValueSemantics({parent->getTypeForDecl(), &Impl}), {});
+        if (semanticsKind == CxxValueSemanticsKind::MissingLifetimeOperation)
           return nullptr;
       }
 
@@ -3396,6 +3469,12 @@ namespace {
       result->setInterfaceType(type);
       result->setIsObjC(false);
       result->setIsDynamic(false);
+      if (decl->getType().isConstQualified()) {
+        // Note that in C++ there are ways to change the values of const
+        // members, so we don't use WriteImplKind::Immutable storage.
+        assert(result->supportsMutation());
+        result->overwriteSetterAccess(AccessLevel::Private);
+      }
       Impl.recordImplicitUnwrapForDecl(result,
                                        importedType.isImplicitlyUnwrapped());
 
@@ -3533,63 +3612,34 @@ namespace {
              isa<clang::ObjCMethodDecl>(decl) &&
                  "checkBridgingAttrs called with a clang::NamedDecl which is "
                  "neither clang::FunctionDecl nor clang::ObjCMethodDecl");
-      bool returnsRetainedAttrIsPresent = false;
-      bool returnsUnretainedAttrIsPresent = false;
-      if (decl->hasAttrs()) {
-        for (const auto *attr : decl->getAttrs()) {
-          if (const auto *swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr)) {
-            if (swiftAttr->getAttribute() == "returns_unretained") {
-              returnsUnretainedAttrIsPresent = true;
-            } else if (swiftAttr->getAttribute() == "returns_retained") {
-              returnsRetainedAttrIsPresent = true;
-            }
-          }
-        }
-      }
+
+      auto attrInfo = importer::ReturnOwnershipInfo(decl);
 
       HeaderLoc loc(decl->getLocation());
       const auto retType =
           isa<clang::FunctionDecl>(decl)
               ? cast<clang::FunctionDecl>(decl)->getReturnType()
               : cast<clang::ObjCMethodDecl>(decl)->getReturnType();
-      if (isForeignReferenceTypeWithoutImmortalAttrs(retType)) {
-        if (returnsRetainedAttrIsPresent && returnsUnretainedAttrIsPresent) {
+      clang::QualType pointeeType = retType;
+      if (retType->isPointerType() || retType->isReferenceType()) {
+        pointeeType = retType->getPointeeType();
+      }
+
+      clang::RecordDecl *recordDecl = nullptr;
+      if (const auto *recordType = pointeeType->getAs<clang::RecordType>()) {
+        recordDecl = recordType->getDecl();
+      }
+
+      if (recordDecl && recordHasReferenceSemantics(recordDecl) &&
+          !hasImmortalAttrs(recordDecl)) {
+        if (attrInfo.hasConflictingAttr()) {
           Impl.diagnose(loc, diag::both_returns_retained_returns_unretained,
                         decl);
-        } else if (!returnsRetainedAttrIsPresent &&
-                   !returnsUnretainedAttrIsPresent) {
-          bool unannotatedAPIWarningNeeded = false;
-          if (isa<clang::FunctionDecl>(decl) &&
-              !isa<clang::CXXDeductionGuideDecl>(decl)) {
-            if (const auto *methodDecl = dyn_cast<clang::CXXMethodDecl>(decl)) {
-              // FIXME: In the future we should support SWIFT_RETURNS_RETAINED
-              // and SWIFT_RETURNS_UNRETAINED for overloaded C++ operators
-              // returning SWIFT_SHARED_REFERENCE types
-              if (!isa<clang::CXXConstructorDecl>(methodDecl) &&
-                  !isa<clang::CXXDestructorDecl>(methodDecl) &&
-                  !methodDecl->isOverloadedOperator() &&
-                  methodDecl->isUserProvided()) {
-                // normal c++ member method
-                unannotatedAPIWarningNeeded = true;
-              }
-            } else {
-              // global or top-level C/C++ function
-              unannotatedAPIWarningNeeded = true;
-            }
-          } else if (isa<clang::ObjCMethodDecl>(decl)) {
-            unannotatedAPIWarningNeeded = true;
-          }
-
-          if (unannotatedAPIWarningNeeded) {
-            HeaderLoc loc(decl->getLocation());
-            Impl.diagnose(loc, diag::no_returns_retained_returns_unretained,
-                          decl);
-          }
         } else if (const auto *methodDecl =
                        dyn_cast<clang::CXXMethodDecl>(decl)) {
           // Warning for annotated overloaded C++ operators as they currently
           // follow Swift method's convention and always return owned.
-          if (methodDecl->isOverloadedOperator()) {
+          if (methodDecl->isOverloadedOperator() && attrInfo.hasRetainAttr()) {
             Impl.diagnose(
                 loc,
                 diag::
@@ -3598,7 +3648,19 @@ namespace {
           }
         }
       } else {
-        if (returnsRetainedAttrIsPresent || returnsUnretainedAttrIsPresent) {
+        if (attrInfo.hasRetainAttr()) {
+          if (const auto *functionDecl = dyn_cast<clang::FunctionDecl>(decl)) {
+            // Skip diagnostics for template instantiations and template-dependent
+            // return types. We cannot determine at import time whether T or T* will
+            // be instantiated as a SWIFT_SHARED_REFERENCE type or not, so we avoid
+            // emitting potentially incorrect warnings for these cases.
+            if (functionDecl->isTemplateInstantiation() ||
+                functionDecl->getReturnType()->isInstantiationDependentType() ||
+                functionDecl->getReturnType()->isDependentType()) {
+              return;
+            }
+          }
+
           Impl.diagnose(
               loc,
               diag::
@@ -3621,14 +3683,16 @@ namespace {
         return true;
 
       if (importedName.isSubscriptAccessor()) {
-        assert(func->getParameters()->size() == 1);
-        auto parameter = func->getParameters()->get(0);
-        auto parameterType = parameter->getTypeInContext();
-        if (!typeDecl || !parameterType)
-          return false;
-        if (parameter->isInOut())
-          // Subscripts with inout parameters are not allowed in Swift.
-          return false;
+        SmallVector<TypeBase *> params;
+        for (auto parameter : *(func->getParameters())) {
+          auto parameterType = parameter->getTypeInContext();
+          if (!typeDecl || !parameterType)
+            return false;
+          if (parameter->isInOut())
+            // Subscripts with inout parameters are not allowed in Swift.
+            return false;
+          params.push_back(parameterType.getPointer());
+        }
         // Subscript setter is marked as mutating in Swift even if the
         // C++ `operator []` is `const`.
         if (importedName.getAccessorKind() ==
@@ -3637,7 +3701,8 @@ namespace {
             !typeDecl->getDeclaredType()->isForeignReferenceType())
           func->setSelfAccessKind(SelfAccessKind::Mutating);
 
-        auto &getterAndSetter = Impl.cxxSubscripts[{typeDecl, parameterType}];
+        auto &getterAndSetterMap = Impl.cxxSubscripts[typeDecl];
+        auto &getterAndSetter = getterAndSetterMap[params];
 
         switch (importedName.getAccessorKind()) {
         case ImportedAccessorKind::SubscriptGetter:
@@ -3863,9 +3928,8 @@ namespace {
               Impl.SwiftContext, SourceLoc(), templateParams, SourceLoc());
       }
 
-      bool importFuncWithoutSignature =
-          isa<clang::CXXMethodDecl>(decl) && Impl.importSymbolicCXXDecls;
-      if (!dc->isModuleScopeContext() && !isa<clang::CXXMethodDecl>(decl)) {
+      if (!dc->isModuleScopeContext() && !isClangNamespace(dc) &&
+          !isa<clang::CXXMethodDecl>(decl)) {
         // Handle initializers.
         if (name.getBaseName().isConstructor()) {
           assert(!accessorInfo);
@@ -3930,39 +3994,12 @@ namespace {
           importedType =
               Impl.importFunctionReturnType(dc, decl, allowNSUIntegerAsInt);
       } else {
-        if (importFuncWithoutSignature) {
-          importedType = ImportedType{Impl.SwiftContext.getVoidType(), false};
-          if (decl->param_empty())
-            bodyParams = ParameterList::createEmpty(Impl.SwiftContext);
-          else {
-            llvm::SmallVector<ParamDecl *, 4> params;
-            for (const auto &param : decl->parameters()) {
-
-              Identifier bodyName =
-                  Impl.importFullName(param, Impl.CurrentVersion)
-                      .getBaseIdentifier(Impl.SwiftContext);
-              auto paramInfo = Impl.createDeclWithClangNode<ParamDecl>(
-                  param, AccessLevel::Private, SourceLoc(), SourceLoc(),
-                  Identifier(), Impl.importSourceLoc(param->getLocation()),
-                  bodyName, Impl.ImportedHeaderUnit);
-              paramInfo->setSpecifier(ParamSpecifier::Default);
-              paramInfo->setInterfaceType(Impl.SwiftContext.TheAnyType);
-              if (param->hasDefaultArg()) {
-                paramInfo->setDefaultArgumentKind(DefaultArgumentKind::Normal);
-                paramInfo->setDefaultValueStringRepresentation("cxxDefaultArg");
-              }
-              params.push_back(paramInfo);
-            }
-            bodyParams = ParameterList::create(Impl.SwiftContext, params);
-          }
-        } else {
-          // Import the function type. If we have parameters, make sure their
-          // names get into the resulting function type.
-          importedType = Impl.importFunctionParamsAndReturnType(
-              dc, decl, {decl->param_begin(), decl->param_size()},
-              decl->isVariadic(), isInSystemModule(dc), name, bodyParams,
-              templateParams);
-        }
+        // Import the function type. If we have parameters, make sure their
+        // names get into the resulting function type.
+        importedType = Impl.importFunctionParamsAndReturnType(
+            dc, decl, {decl->param_begin(), decl->param_size()},
+            decl->isVariadic(), isInSystemModule(dc), name, bodyParams,
+            templateParams);
 
         if (auto *mdecl = dyn_cast<clang::CXXMethodDecl>(decl)) {
           if (mdecl->isStatic()) {
@@ -4020,6 +4057,15 @@ namespace {
         if (ctordecl->isCopyConstructor() || ctordecl->isMoveConstructor())
           return nullptr;
 
+        // Don't import the generic ctors of std::span, rely on the ctors that
+        // we instantiate when conforming to the overlay. These generic ctors
+        // can cause crashes in codegen.
+        // FIXME: figure out why.
+        const auto *parent = ctordecl->getParent();
+        if (funcTemplate && parent->isInStdNamespace() &&
+            parent->getIdentifier() && parent->getName() == "span")
+          return nullptr;
+
         DeclName ctorName(Impl.SwiftContext, DeclBaseName::createConstructor(),
                           bodyParams);
         result = Impl.createDeclWithClangNode<ConstructorDecl>(
@@ -4050,9 +4096,13 @@ namespace {
           }
           if (selfIdx) {
             func->setSelfIndex(selfIdx.value());
-            if (Impl.SwiftContext.LangOpts.hasFeature(
-                    Feature::AddressableParameters))
-              func->getImplicitSelfDecl()->setAddressable();
+            // FIXME: Make this work when SIL Opaque Values are enabled.
+            // Currently, addressable parameters and opaque values are at odds.
+            if (!dc->getDeclaredInterfaceType()->hasReferenceSemantics() &&
+                !importedName.importAsMember() &&
+                !Impl.SwiftContext.SILOpts.EnableSILOpaqueValues)
+              func->getAttrs().add(new (Impl.SwiftContext)
+                                       AddressableSelfAttr(true));
           } else {
             func->setStatic();
             func->setImportAsStaticMember();
@@ -4060,12 +4110,10 @@ namespace {
         }
         func->setAccess(importer::convertClangAccess(decl->getAccess()));
 
-        if (!importFuncWithoutSignature) {
-          bool success = processSpecialImportedFunc(
-              func, importedName, decl->getOverloadedOperator());
-          if (!success)
-            return nullptr;
-        }
+        bool success = processSpecialImportedFunc(
+            func, importedName, decl->getOverloadedOperator());
+        if (!success)
+          return nullptr;
       }
 
       result->setIsObjC(false);
@@ -4102,13 +4150,58 @@ namespace {
       return false;
     }
 
+    // Inject lifetime annotations selectively for some STL types so we can use
+    // unsafeAddress to avoid copies.
+    bool inferSelfDependence(const clang::FunctionDecl *decl,
+                             AbstractFunctionDecl *result, size_t returnIdx) {
+      const auto *method = dyn_cast<clang::CXXMethodDecl>(decl);
+      if (!method)
+        return false;
+      const auto *enclosing = method->getParent();
+      if (enclosing->isInStdNamespace() &&
+          (enclosing->getName() == "unique_ptr" ||
+           enclosing->getName() == "shared_ptr") &&
+          method->isOverloadedOperator() &&
+          method->getOverloadedOperator() == clang::OO_Star) {
+        SmallVector<LifetimeDependenceInfo, 1> lifetimeDependencies;
+        SmallBitVector dependenciesOfRet(returnIdx);
+        dependenciesOfRet[result->getSelfIndex()] = true;
+        lifetimeDependencies.push_back(LifetimeDependenceInfo(
+            nullptr, IndexSubset::get(Impl.SwiftContext, dependenciesOfRet),
+            returnIdx,
+            /*isImmortal*/ false));
+        Impl.SwiftContext.evaluator.cacheOutput(
+            LifetimeDependenceInfoRequest{result},
+            Impl.SwiftContext.AllocateCopy(lifetimeDependencies));
+        Impl.returnsSelfDependentValue.insert(result);
+        return true;
+      }
+      return false;
+    }
+
+    static bool isReturnDependsOnSelf(
+        AbstractFunctionDecl *f,
+        const ArrayRef<LifetimeDependenceInfo> &lifetimeDeps) {
+      if (isa<ConstructorDecl>(f) || !f->getImportAsMemberStatus().isInstance())
+        return false;
+      for (auto dependence : lifetimeDeps) {
+        auto returnIdx = f->getParameters()->size() + !isa<ConstructorDecl>(f);
+        if (!dependence.hasInheritLifetimeParamIndices() &&
+            dependence.hasScopeLifetimeParamIndices() &&
+            dependence.getTargetIndex() == returnIdx)
+          return dependence.getScopeIndices()->contains(f->getSelfIndex());
+      }
+      return false;
+    }
+
     void addLifetimeDependencies(const clang::FunctionDecl *decl,
                                  AbstractFunctionDecl *result) {
       if (decl->getTemplatedKind() == clang::FunctionDecl::TK_FunctionTemplate)
         return;
 
       // FIXME: support C functions imported as members.
-      if (result->getImportAsMemberStatus().isImportAsMember() &&
+      if (!isClangNamespace(result->getDeclContext()) &&
+          result->getImportAsMemberStatus().isImportAsMember() &&
           !isa<clang::CXXMethodDecl, clang::ObjCMethodDecl>(decl))
         return;
 
@@ -4119,10 +4212,19 @@ namespace {
                    CxxEscapability::Unknown) != CxxEscapability::NonEscapable;
       };
 
+      auto swiftParams = result->getParameters();
+      bool hasSelf =
+          result->hasImplicitSelfDecl() && !isa<ConstructorDecl>(result);
+      auto returnIdx = swiftParams->size() + hasSelf;
+
+      if (inferSelfDependence(decl, result, returnIdx))
+        return;
+
       // FIXME: this uses '0' as the result index. That only works for
       // standalone functions with no parameters.
       // See markReturnsUnsafeNonescapable() for a general approach.
       auto &ASTContext = result->getASTContext();
+
       SmallVector<LifetimeDependenceInfo, 1> lifetimeDependencies;
       LifetimeDependenceInfo immortalLifetime(nullptr, nullptr, 0,
                                               /*isImmortal*/ true);
@@ -4145,10 +4247,7 @@ namespace {
         }
       };
 
-      auto swiftParams = result->getParameters();
-      bool hasSelf =
-          result->hasImplicitSelfDecl() && !isa<ConstructorDecl>(result);
-      const auto dependencyVecSize = swiftParams->size() + hasSelf;
+      const auto dependencyVecSize = returnIdx;
       SmallBitVector inheritLifetimeParamIndicesForReturn(dependencyVecSize);
       SmallBitVector scopedLifetimeParamIndicesForReturn(dependencyVecSize);
       SmallBitVector paramHasAnnotation(dependencyVecSize);
@@ -4175,14 +4274,14 @@ namespace {
             for (auto param : attr->params()) {
               // FIXME: Swift assumes no escaping to globals. We should diagnose
               // this.
-              if (param == clang::LifetimeCaptureByAttr::GLOBAL ||
-                  param == clang::LifetimeCaptureByAttr::UNKNOWN ||
-                  param == clang::LifetimeCaptureByAttr::INVALID)
+              if (param == clang::LifetimeCaptureByAttr::Global ||
+                  param == clang::LifetimeCaptureByAttr::Unknown ||
+                  param == clang::LifetimeCaptureByAttr::Invalid)
                 continue;
 
               paramHasAnnotation[idx] = true;
               if (isa<clang::CXXMethodDecl>(decl) &&
-                  param == clang::LifetimeCaptureByAttr::THIS) {
+                  param == clang::LifetimeCaptureByAttr::This) {
                 auto [it, inserted] = inheritedArgDependences.try_emplace(
                     result->getSelfIndex(), SmallBitVector(dependencyVecSize));
                 it->second[idx] = true;
@@ -4227,7 +4326,7 @@ namespace {
                 ? IndexSubset::get(Impl.SwiftContext,
                                    scopedLifetimeParamIndicesForReturn)
                 : nullptr,
-            swiftParams->size() + hasSelf,
+            returnIdx,
             /*isImmortal*/ false));
       else if (auto *ctordecl = dyn_cast<clang::CXXConstructorDecl>(decl)) {
         // Assume default constructed view types have no dependencies.
@@ -4266,6 +4365,10 @@ namespace {
       }
 
       Impl.diagnoseTargetDirectly(decl);
+
+      if (isReturnDependsOnSelf(result, lifetimeDependencies)) {
+        Impl.returnsSelfDependentValue.insert(result);
+      }
     }
 
     void finishFuncDecl(const clang::FunctionDecl *decl,
@@ -4290,6 +4393,7 @@ namespace {
       }
 
       recordObjCOverride(result);
+      Impl.swiftify(result);
     }
 
     static bool hasComputedPropertyAttr(const clang::Decl *decl) {
@@ -4348,7 +4452,12 @@ namespace {
             // Create a thunk that will perform dynamic dispatch.
             // TODO: we don't have to import the actual `method` in this case,
             // we can just synthesize a thunk and import that instead.
-            auto result = synthesizer.makeVirtualMethod(decl);
+
+            llvm::SmallString<64> swiftName;
+            funcDecl->getName().getString(swiftName);
+            FuncDecl *result =
+                synthesizer.makeVirtualMethod(decl, swiftName.str());
+
             if (result) {
               return result;
             } else {
@@ -4379,6 +4488,33 @@ namespace {
     }
 
     Decl *VisitFieldDecl(const clang::FieldDecl *decl) {
+      if (decl->hasAttr<clang::NoUniqueAddressAttr>()) {
+        if (const auto *rd = decl->getType()->getAsRecordDecl()) {
+          // Clang can store the next field in the padding of this one. Swift
+          // does not support this yet so let's not import the field and
+          // represent it with an opaque blob in codegen.
+          //
+          // This check is not relevant when importing the decl symbolically
+          // (since that isn't used for codegen). In fact, we need to avoid this
+          // check because symbolic imports can expose us to dependent types
+          // whose ASTRecordLayout cannot be queried.
+          const auto &fieldLayout =
+              decl->getASTContext().getASTRecordLayout(rd);
+          auto &clangCtx = decl->getASTContext();
+          if (!decl->isZeroSize(clangCtx) &&
+              fieldLayout.getDataSize() != fieldLayout.getSize()) {
+            const auto *parent = decl->getParent();
+            auto currIdx = decl->getFieldIndex();
+            auto nextIdx = currIdx + 1;
+            const auto &parentLayout = clangCtx.getASTRecordLayout(parent);
+            if (parentLayout.getFieldCount() > nextIdx &&
+                parentLayout.getFieldOffset(nextIdx) <
+                    (parentLayout.getFieldOffset(currIdx) +
+                     clangCtx.toBits(fieldLayout.getSize())))
+              return nullptr;
+          }
+        }
+      }
       // Fields are imported as variables.
       std::optional<ImportedName> correctSwiftName;
       ImportedName importedName;
@@ -4416,8 +4552,8 @@ namespace {
           return nullptr;
       }
 
-      auto fieldType = decl->getType();
-      ImportedType importedType = findOptionSetType(fieldType, Impl);
+      auto fieldType = desugarIfElaborated(decl->getType());
+      ImportedType importedType = importer::findOptionSetEnum(fieldType, Impl);
 
       if (!importedType)
         importedType =
@@ -4461,6 +4597,10 @@ namespace {
         // FIXME: Temporarily unreachable because of check above.
         markAsVariant(result, *correctSwiftName);
 
+      if (decl->isAnonymousStructOrUnion())
+        Impl.markUnavailable(
+            result, "refer to the members of the anonymous type instead");
+
       return result;
     }
 
@@ -4493,19 +4633,86 @@ namespace {
       if (dc->isTypeContext())
         isStatic = true;
 
-      // For now we don't import static constexpr
-      if (isStatic && decl->isConstexpr())
+      // For now we don't import static constexpr. TODO: Lift this restriction.
+      if (isStatic && !isClangNamespace(dc) && decl->isConstexpr())
         return nullptr;
 
       auto introducer = Impl.shouldImportGlobalAsLet(decl->getType())
                         ? VarDecl::Introducer::Let
                         : VarDecl::Introducer::Var;
-      auto result = Impl.createDeclWithClangNode<VarDecl>(
-          decl, importer::convertClangAccess(decl->getAccess()),
-          /*IsStatic*/ isStatic, introducer,
-          Impl.importSourceLoc(decl->getLocation()), name, dc);
-      result->setIsObjC(false);
-      result->setIsDynamic(false);
+
+      ValueDecl *result = nullptr;
+
+      bool initIsEvaluatable = false;
+      if (Impl.SwiftContext.ClangImporterOpts.EnableConstValueImporting) {
+        if (auto init = decl->getInit()) {
+          // Don't import values when type-dependent or value-dependent.
+          bool typeDependent = decl->getType()->isDependentType();
+          bool valueDependent = init->isValueDependent();
+
+          initIsEvaluatable = !typeDependent && !valueDependent;
+        }
+      }
+
+      // If the variable is const (we're importing it as a let), and has an
+      // initializer, then ask Clang for its constant value and synthesize a
+      // getter with that value.
+      if (introducer == VarDecl::Introducer::Let && initIsEvaluatable) {
+        auto val = decl->evaluateValue();
+        // For now, only import integer and float constants. If in the future
+        // SwiftDeclSynthesizer::createConstant becomes able to import more
+        // types, we can lift this restriction.
+        if (val && (val->isFloat() || val->isInt())) {
+          auto type = Impl.importTypeIgnoreIUO(
+              decl->getType(), ImportTypeKind::Value,
+              ImportDiagnosticAdder(Impl, decl, decl->getLocation()),
+              isInSystemModule(dc), Bridgeability::None, ImportTypeAttrs());
+
+          // Do not attempt to import CGFloat values, for now. Importing
+          // CGFloats is special cased in the importer, and needs more handling.
+          bool isCGFloat = (type && type->isCGFloat()) ||
+                           (type && synthesizer.isCGFloat(type));
+          // Do not attempts to import ObjCBool values, for similar reasons.
+          bool isObjCBool = (type && type->isObjCBool()) ||
+                            (type && synthesizer.isObjCBool(type));
+          // Do not attempts to import CWideChar (wchar_t) values. CWideChar is
+          // a typealias for Unicode.Scalar, which does not
+          // implement _ExpressibleByBuiltinIntegerLiteral.
+          // FIXME: import using _ExpressibleByUnicodeScalarLiteral.
+          bool isUnicodeScalar = (type && type->isUnicodeScalar()) ||
+                                 (type && synthesizer.isUnicodeScalar(type));
+
+          if (type && !isCGFloat && !isObjCBool && !isUnicodeScalar) {
+            auto convertKind = ConstantConvertKind::None;
+            // Request conversions on enums, and swift_wrapper((enum/struct))
+            // types
+            if (decl->getType()->isEnumeralType()) {
+              if (type->getEnumOrBoundGenericEnum()) {
+                // When importing as an enum, also apply implicit force unwrap
+                convertKind = ConstantConvertKind::ConstructionWithUnwrap;
+              } else {
+                convertKind = ConstantConvertKind::Construction;
+              }
+            } else if (findSwiftNewtype(decl, Impl.getClangSema(),
+                                      Impl.CurrentVersion))
+              convertKind = ConstantConvertKind::Construction;
+
+            result = synthesizer.createConstant(
+                name, dc, type, *val, convertKind, isStatic, decl,
+                importer::convertClangAccess(decl->getAccess()));
+          }
+        }
+      }
+
+      // Otherwise, import as an external declaration
+      if (!result) {
+        result = Impl.createDeclWithClangNode<VarDecl>(
+            decl, importer::convertClangAccess(decl->getAccess()),
+            /*IsStatic*/ isStatic, introducer,
+            Impl.importSourceLoc(decl->getLocation()), name, dc);
+        result->setIsObjC(false);
+        result->setIsDynamic(false);
+      }
 
       // If imported as member, the member should be final.
       if (dc->getSelfClassDecl())
@@ -4516,9 +4723,22 @@ namespace {
       if (correctSwiftName)
         markAsVariant(result, *correctSwiftName);
 
+      // If the decl represents an availability domain, eagerly synthesize its
+      // `if #available` predicate function.
+      if (decl->hasAttrs() &&
+          llvm::any_of(decl->getAttrs(), [](clang::Attr *attr) {
+            return isa<clang::AvailabilityDomainAttr>(attr);
+          }))
+        (void)synthesizer.makeAvailabilityDomainPredicate(decl);
+
       return result;
     }
 
+    Decl *VisitVarTemplatePartialSpecializationDecl(
+        const clang::VarTemplatePartialSpecializationDecl *decl) {
+      return nullptr;
+    }
+
     Decl *VisitImplicitParamDecl(const clang::ImplicitParamDecl *decl) {
       // Parameters are never directly imported.
       return nullptr;
@@ -4563,15 +4783,10 @@ namespace {
       if (name.empty())
         return nullptr;
 
-      if (Impl.importSymbolicCXXDecls)
-        // Import an unspecialized C++ class template as a Swift value/class
-        // type in symbolic mode.
-        return Impl.importDecl(decl->getTemplatedDecl(), Impl.CurrentVersion);
-
       auto loc = Impl.importSourceLoc(decl->getLocation());
       auto dc = Impl.importDeclContextOf(
           decl, importedName.getEffectiveContext());
-      
+
       SmallVector<GenericTypeParamDecl *, 4> genericParams;
       for (auto &param : *decl->getTemplateParameters()) {
         auto genericParamDecl =
@@ -4588,7 +4803,7 @@ namespace {
 
       auto structDecl = Impl.createDeclWithClangNode<StructDecl>(
           decl, importer::convertClangAccess(decl->getAccess()), loc, name, loc,
-          std::nullopt, genericParamList, dc);
+          ArrayRef<InheritedEntry>(), genericParamList, dc);
 
       auto attr = AvailableAttr::createUniversallyUnavailable(
           Impl.SwiftContext, "Un-specialized class templates are not currently "
@@ -5352,9 +5567,8 @@ namespace {
                       { }, dc, nullptr, decl);
       Impl.SwiftContext.evaluator.cacheOutput(ExtendedTypeRequest{result},
                                               objcClass->getDeclaredType());
-      Impl.SwiftContext.evaluator.cacheOutput(ExtendedNominalRequest{result},
-                                              std::move(objcClass));
-      
+      result->setExtendedNominal(objcClass);
+
       Identifier categoryName;
       if (!decl->getName().empty())
         categoryName = Impl.SwiftContext.getIdentifier(decl->getName());
@@ -5601,7 +5815,8 @@ namespace {
                                            /*allowForwardDeclaration=*/true),
                 Impl.importSourceLoc(decl->getBeginLoc()),
                 Impl.importSourceLoc(decl->getLocation()), name,
-                ArrayRef<PrimaryAssociatedTypeName>(), std::nullopt,
+                ArrayRef<PrimaryAssociatedTypeName>(),
+                ArrayRef<InheritedEntry>(),
                 /*TrailingWhere=*/nullptr);
 
             Impl.ImportedDecls[{decl->getCanonicalDecl(), getVersion()}] = result;
@@ -5641,7 +5856,7 @@ namespace {
           decl, AccessLevel::Public, dc,
           Impl.importSourceLoc(decl->getBeginLoc()),
           Impl.importSourceLoc(decl->getLocation()), name,
-          ArrayRef<PrimaryAssociatedTypeName>(), std::nullopt,
+          ArrayRef<PrimaryAssociatedTypeName>(), ArrayRef<InheritedEntry>(),
           /*TrailingWhere=*/nullptr);
 
       addObjCAttribute(result, Impl.importIdentifier(decl->getIdentifier()));
@@ -5684,7 +5899,7 @@ namespace {
 
         auto result = Impl.createDeclWithClangNode<ClassDecl>(
             decl, AccessLevel::Public, SourceLoc(), name, SourceLoc(),
-            std::nullopt, nullptr, dc,
+            ArrayRef<InheritedEntry>(), nullptr, dc,
             /*isActor*/ false);
         if (cacheResult)
           Impl.ImportedDecls[{decl->getCanonicalDecl(), getVersion()}] = result;
@@ -5798,7 +6013,8 @@ namespace {
       // Create the class declaration and record it.
       auto result = Impl.createDeclWithClangNode<ClassDecl>(
           decl, access, Impl.importSourceLoc(decl->getBeginLoc()), name,
-          Impl.importSourceLoc(decl->getLocation()), std::nullopt, nullptr, dc,
+          Impl.importSourceLoc(decl->getLocation()), ArrayRef<InheritedEntry>(),
+          nullptr, dc,
           /*isActor*/ false);
 
       // Import generic arguments, if any.
@@ -6009,8 +6225,8 @@ namespace {
         }
       }
 
-      auto fieldType = decl->getType();
-      ImportedType importedType = findOptionSetType(fieldType, Impl);
+      auto fieldType = desugarIfElaborated(decl->getType());
+      ImportedType importedType = importer::findOptionSetEnum(fieldType, Impl);
 
       if (!importedType)
         importedType = Impl.importPropertyType(decl, isInSystemModule(dc));
@@ -6272,7 +6488,7 @@ SwiftDeclConverter::importCFClassType(const clang::TypedefNameDecl *decl,
 
   auto theClass = Impl.createDeclWithClangNode<ClassDecl>(
       decl, AccessLevel::Public, SourceLoc(), className, SourceLoc(),
-      std::nullopt, nullptr, dc, /*isActor*/ false);
+      ArrayRef<InheritedEntry>(), nullptr, dc, /*isActor*/ false);
   theClass->setSuperclass(superclass);
   theClass->setAddedImplicitInitializers(); // suppress all initializers
   theClass->setHasMissingVTableEntries(false);
@@ -6411,6 +6627,20 @@ static bool conformsToProtocolInOriginalModule(NominalTypeDecl *nominal,
   return false;
 }
 
+/// Determine whether the given nominal type was imported with an OptionSet
+/// conformance.
+static bool isImportedOptionSet(NominalTypeDecl *nominal) {
+  for (auto attr : nominal->getAttrs()) {
+    if (auto synthesizedAttr = dyn_cast<SynthesizedProtocolAttr>(attr)) {
+      if (synthesizedAttr->getProtocol()->isSpecificProtocol(
+              KnownProtocolKind::OptionSet))
+        return true;
+    }
+  }
+
+  return false;
+}
+
 Decl *
 SwiftDeclConverter::importSwiftNewtype(const clang::TypedefNameDecl *decl,
                                        clang::SwiftNewTypeAttr *newtypeAttr,
@@ -6438,7 +6668,7 @@ SwiftDeclConverter::importSwiftNewtype(const clang::TypedefNameDecl *decl,
 
   auto structDecl = Impl.createDeclWithClangNode<StructDecl>(
       decl, importer::convertClangAccess(decl->getAccess()), Loc, name, Loc,
-      std::nullopt, nullptr, dc);
+      ArrayRef<InheritedEntry>(), nullptr, dc);
 
   // Import the type of the underlying storage
   ImportDiagnosticAdder addImportDiag(Impl, decl, decl->getLocation());
@@ -6485,6 +6715,11 @@ SwiftDeclConverter::importSwiftNewtype(const clang::TypedefNameDecl *decl,
   addKnown(KnownProtocolKind::RawRepresentable);
   addKnown(KnownProtocolKind::SwiftNewtypeWrapper);
 
+  // If this type was also imported as an OptionSet, include those typealiases.
+  if (isImportedOptionSet(structDecl)) {
+    Impl.addOptionSetTypealiases(structDecl);
+  }
+
   // Local function to add a known protocol only when the
   // underlying type conforms to it.
   auto computedNominal = computedPropertyUnderlyingType->getAnyNominal();
@@ -6739,14 +6974,12 @@ Decl *SwiftDeclConverter::importEnumCaseAlias(
 NominalTypeDecl *
 SwiftDeclConverter::importAsOptionSetType(DeclContext *dc, Identifier name,
                                           const clang::EnumDecl *decl) {
-  ASTContext &ctx = Impl.SwiftContext;
-
   auto Loc = Impl.importSourceLoc(decl->getLocation());
 
   // Create a struct with the underlying type as a field.
   auto structDecl = Impl.createDeclWithClangNode<StructDecl>(
       decl, importer::convertClangAccess(decl->getAccess()), Loc, name, Loc,
-      std::nullopt, nullptr, dc);
+      ArrayRef<InheritedEntry>(), nullptr, dc);
   Impl.ImportedDecls[{decl->getCanonicalDecl(), getVersion()}] = structDecl;
 
   // Compute the underlying type.
@@ -6759,10 +6992,7 @@ SwiftDeclConverter::importAsOptionSetType(DeclContext *dc, Identifier name,
 
   synthesizer.makeStructRawValued(structDecl, underlyingType,
                                   {KnownProtocolKind::OptionSet});
-  auto selfType = structDecl->getDeclaredInterfaceType();
-  Impl.addSynthesizedTypealias(structDecl, ctx.Id_Element, selfType);
-  Impl.addSynthesizedTypealias(structDecl, ctx.Id_ArrayLiteralElement,
-                               selfType);
+  Impl.addOptionSetTypealiases(structDecl);
   return structDecl;
 }
 
@@ -6974,8 +7204,7 @@ SwiftDeclConverter::getImplicitProperty(ImportedName importedName,
       getAccessorPropertyType(getter, false, getterName.getSelfIndex());
   if (propertyType.isNull())
     return nullptr;
-  if (auto elaborated = dyn_cast<clang::ElaboratedType>(propertyType))
-    propertyType = elaborated->desugar();
+  propertyType = desugarIfElaborated(propertyType);
 
   // If there is a setter, check that the property it implies
   // matches that of the getter.
@@ -7001,24 +7230,7 @@ SwiftDeclConverter::getImplicitProperty(ImportedName importedName,
   if (dc->isTypeContext() && !getterName.getSelfIndex())
     isStatic = true;
 
-  ImportedType importedType;
-
-  // Sometimes we import unavailable typedefs as enums. If that's the case,
-  // use the enum, not the typedef here.
-  if (auto typedefType = dyn_cast<clang::TypedefType>(propertyType.getTypePtr())) {
-    if (Impl.isUnavailableInSwift(typedefType->getDecl())) {
-      if (auto clangEnum = findAnonymousEnumForTypedef(Impl.SwiftContext, typedefType)) {
-        // If this fails, it means that we need a stronger predicate for
-        // determining the relationship between an enum and typedef.
-        assert(clangEnum.value()->getIntegerType()->getCanonicalTypeInternal() ==
-               typedefType->getCanonicalTypeInternal());
-        if (auto swiftEnum = Impl.importDecl(*clangEnum, Impl.CurrentVersion)) {
-          importedType = {cast<TypeDecl>(swiftEnum)->getDeclaredInterfaceType(),
-                          false};
-        }
-      }
-    }
-  }
+  ImportedType importedType = importer::findOptionSetEnum(propertyType, Impl);
 
   if (!importedType) {
     // Compute the property type.
@@ -8558,6 +8770,26 @@ bool importer::isSpecialUIKitStructZeroProperty(const clang::NamedDecl *decl) {
   return ident->isStr("UIEdgeInsetsZero") || ident->isStr("UIOffsetZero");
 }
 
+bool importer::isSpecialAppKitFunctionKeyProperty(
+    const clang::NamedDecl *decl) {
+  auto constant = dyn_cast<clang::EnumConstantDecl>(decl);
+  if (!constant)
+    return false;
+
+  auto module = constant->getOwningModule();
+  if (!module || module->getTopLevelModuleName() != "AppKit")
+    return false;
+
+  clang::DeclarationName name = constant->getDeclName();
+  const clang::IdentifierInfo *ident = name.getAsIdentifierInfo();
+  if (!ident)
+    return false;
+  auto rawName = ident->getName();
+
+  return rawName.starts_with("NS") &&
+         (rawName.ends_with("FunctionKey") || rawName.ends_with("Character"));
+}
+
 bool importer::hasSameUnderlyingType(const clang::Type *a,
                                      const clang::TemplateTypeParmDecl *b) {
   while (a->isPointerType() || a->isReferenceType())
@@ -8566,17 +8798,16 @@ bool importer::hasSameUnderlyingType(const clang::Type *a,
 }
 
 SourceFile &ClangImporter::Implementation::getClangSwiftAttrSourceFile(
-    ModuleDecl &module,
-    StringRef attributeText,
-    bool cached
-) {
+    Decl *MappedDecl, StringRef attributeText, bool cached) {
+  auto *module = MappedDecl->getDeclContext()->getParentModule();
+
   ::TinyPtrVector<SourceFile *> *sourceFiles = nullptr;
   if (cached) {
     sourceFiles = &ClangSwiftAttrSourceFiles[attributeText];
 
     // Check whether we've already created a source file.
     for (auto sourceFile : *sourceFiles) {
-      if (sourceFile->getParentModule() == &module)
+      if (sourceFile->getParentModule() == module)
         return *sourceFile;
     }
   }
@@ -8586,20 +8817,17 @@ SourceFile &ClangImporter::Implementation::getClangSwiftAttrSourceFile(
   auto &sourceMgr = SwiftContext.SourceMgr;
   auto bufferID = sourceMgr.addMemBufferCopy(attributeText);
 
-  // Note that this is for an attribute.
-  sourceMgr.setGeneratedSourceInfo(
-      bufferID,
-      {
-        GeneratedSourceInfo::AttributeFromClang,
-        CharSourceRange(),
-        sourceMgr.getRangeForBuffer(bufferID),
-        &module
-      }
-  );
+  auto info = GeneratedSourceInfo{GeneratedSourceInfo::AttributeFromClang,
+                                  CharSourceRange(),
+                                  sourceMgr.getRangeForBuffer(bufferID)};
+  info.astNode = static_cast<void *>(module);
+  info.clangNode = MappedDecl->getClangNode();
+
+  sourceMgr.setGeneratedSourceInfo(bufferID, info);
 
   // Create the source file.
-  auto sourceFile = new (SwiftContext)
-      SourceFile(module, SourceFileKind::Library, bufferID);
+  auto sourceFile =
+      new (SwiftContext) SourceFile(*module, SourceFileKind::Library, bufferID);
 
   if (cached)
     sourceFiles->push_back(sourceFile);
@@ -8622,8 +8850,8 @@ void ClangImporter::Implementation::importNontrivialAttribute(
   bool cached = true;
   while (true) {
     // Dig out a source file we can use for parsing.
-    auto &sourceFile = getClangSwiftAttrSourceFile(
-        *MappedDecl->getDeclContext()->getParentModule(), AttrString, cached);
+    auto &sourceFile =
+        getClangSwiftAttrSourceFile(MappedDecl, AttrString, cached);
 
     auto topLevelDecls = sourceFile.getTopLevelDecls();
 
@@ -8682,6 +8910,7 @@ ClangImporter::Implementation::importSwiftAttrAttributes(Decl *MappedDecl) {
 
   std::optional<const clang::SwiftAttrAttr *> seenMainActorAttr;
   const clang::SwiftAttrAttr *seenMutabilityAttr = nullptr;
+  llvm::SmallSet<ProtocolDecl *, 4> conformancesSeen;
 
   auto importAttrsFromDecl = [&](const clang::NamedDecl *ClangDecl) {
     //
@@ -8747,8 +8976,7 @@ ClangImporter::Implementation::importSwiftAttrAttributes(Decl *MappedDecl) {
       // Hard-code @actorIndependent, until Objective-C clients start
       // using nonisolated.
       if (swiftAttr->getAttribute() == "@actorIndependent") {
-        auto attr = new (SwiftContext)
-            NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true);
+        auto attr = NonisolatedAttr::createImplicit(SwiftContext);
         MappedDecl->getAttrs().add(attr);
         continue;
       }
@@ -8765,9 +8993,9 @@ ClangImporter::Implementation::importSwiftAttrAttributes(Decl *MappedDecl) {
         if (lookupConformance(ty, protocol))
           continue;
         auto conformance = SwiftContext.getNormalConformance(
-            ty, protocol, nominal->getLoc(), nominal->getDeclContextForModule(),
-            ProtocolConformanceState::Complete,
-            ProtocolConformanceOptions());
+            ty, protocol, nominal->getLoc(), /*inheritedTypeRepr=*/nullptr,
+            nominal->getDeclContextForModule(),
+            ProtocolConformanceState::Complete, ProtocolConformanceOptions());
         conformance->setSourceKindAndImplyingConformance(
             ConformanceEntryKind::Synthesized, nullptr);
 
@@ -8798,6 +9026,11 @@ ClangImporter::Implementation::importSwiftAttrAttributes(Decl *MappedDecl) {
         continue;
       }
 
+      if (swiftAttr->getAttribute().starts_with("conforms_to:")) {
+        if (auto nominal = dyn_cast<NominalTypeDecl>(MappedDecl))
+          addExplicitProtocolConformance(nominal, swiftAttr, conformancesSeen);
+      }
+
       importNontrivialAttribute(MappedDecl, swiftAttr->getAttribute());
     }
 
@@ -8860,6 +9093,14 @@ ClangImporter::Implementation::importSwiftAttrAttributes(Decl *MappedDecl) {
     }
   }
 
+  // Import explicit conformances from C++ base classes.
+  if (auto nominal = dyn_cast<NominalTypeDecl>(MappedDecl)) {
+    if (auto cxxRecordDecl = dyn_cast<clang::CXXRecordDecl>(ClangDecl)) {
+      addExplicitProtocolConformancesFromBases(
+          nominal, cxxRecordDecl, /*isBase=*/false);
+    }
+  }
+
   // Now that we've collected all @Sendable and @_nonSendable attributes, we
   // can see if we should synthesize a Sendable conformance.
   if (auto nominal = dyn_cast<NominalTypeDecl>(MappedDecl)) {
@@ -8881,23 +9122,33 @@ ClangImporter::Implementation::importSwiftAttrAttributes(Decl *MappedDecl) {
       auto *mappedVar = cast<VarDecl>(MappedDecl);
       if (mappedVar->isStatic() && mappedVar->isLet() &&
           isNSNotificationName(cast<clang::ValueDecl>(ClangDecl)->getType())) {
-        MappedDecl->getAttrs().add(new (SwiftContext) NonisolatedAttr(
-            /*unsafe=*/false, /*implicit=*/true));
+        MappedDecl->getAttrs().add(
+            NonisolatedAttr::createImplicit(SwiftContext));
       }
     }
   }
 }
 
 namespace {
+ValueDecl *getKnownSingleDecl(ASTContext &SwiftContext, StringRef DeclName) {
+  SmallVector<ValueDecl *, 1> decls;
+  SwiftContext.lookupInSwiftModule(DeclName, decls);
+  assert(decls.size() < 2);
+  if (decls.size() != 1) return nullptr;
+  return decls[0];
+}
+
 class SwiftifyInfoPrinter {
 public:
   static const ssize_t SELF_PARAM_INDEX = -2;
   static const ssize_t RETURN_VALUE_INDEX = -1;
   clang::ASTContext &ctx;
+  ASTContext &SwiftContext;
   llvm::raw_ostream &out;
+  MacroDecl &SwiftifyImportDecl;
   bool firstParam = true;
-  SwiftifyInfoPrinter(clang::ASTContext &ctx, llvm::raw_ostream &out)
-      : ctx(ctx), out(out) {
+  SwiftifyInfoPrinter(clang::ASTContext &ctx, ASTContext &SwiftContext, llvm::raw_ostream &out, MacroDecl &SwiftifyImportDecl)
+      : ctx(ctx), SwiftContext(SwiftContext), out(out), SwiftifyImportDecl(SwiftifyImportDecl) {
     out << "@_SwiftifyImport(";
   }
   ~SwiftifyInfoPrinter() { out << ")"; }
@@ -8954,7 +9205,35 @@ class SwiftifyInfoPrinter {
     out << "]";
   }
 
+  void printAvailability() {
+    if (!hasMacroParameter("spanAvailability"))
+      return;
+    printSeparator();
+    out << "spanAvailability: ";
+    printAvailabilityOfType("Span");
+  }
+
 private:
+  bool hasMacroParameter(StringRef ParamName) {
+    for (auto *Param : *SwiftifyImportDecl.parameterList)
+      if (Param->getArgumentName().str() == ParamName)
+        return true;
+    return false;
+  }
+
+  void printAvailabilityOfType(StringRef Name) {
+    ValueDecl *D = getKnownSingleDecl(SwiftContext, Name);
+    out << "\"";
+    llvm::SaveAndRestore<bool> hasAvailbilitySeparatorRestore(firstParam, true);
+    for (auto attr : D->getSemanticAvailableAttrs(/*includingInactive=*/true)) {
+      auto introducedOpt = attr.getIntroduced();
+      if (!introducedOpt.has_value()) continue;
+      printSeparator();
+      out << prettyPlatformString(attr.getPlatform()) << " " << introducedOpt.value();
+    }
+    out << "\"";
+  }
+
   void printSeparator() {
     if (!firstParam) {
       out << ", ";
@@ -8974,13 +9253,261 @@ class SwiftifyInfoPrinter {
 };
 } // namespace
 
-void ClangImporter::Implementation::swiftify(FuncDecl *MappedDecl) {
+namespace {
+struct CountedByExpressionValidator
+    : clang::ConstStmtVisitor<CountedByExpressionValidator, bool> {
+  bool VisitDeclRefExpr(const clang::DeclRefExpr *e) { return true; }
+
+  bool VisitIntegerLiteral(const clang::IntegerLiteral *IL) {
+    switch (IL->getType()->castAs<clang::BuiltinType>()->getKind()) {
+    case clang::BuiltinType::Char_S:
+    case clang::BuiltinType::Char_U:
+    case clang::BuiltinType::UChar:
+    case clang::BuiltinType::SChar:
+    case clang::BuiltinType::Short:
+    case clang::BuiltinType::UShort:
+    case clang::BuiltinType::UInt:
+    case clang::BuiltinType::Long:
+    case clang::BuiltinType::ULong:
+    case clang::BuiltinType::LongLong:
+    case clang::BuiltinType::ULongLong:
+      // These integer literals are printed with a suffix that isn't valid Swift
+      // syntax
+      return false;
+    default:
+      return true;
+    }
+  }
+
+  bool VisitImplicitCastExpr(const clang::ImplicitCastExpr *c) {
+    return this->Visit(c->getSubExpr());
+  }
+  bool VisitParenExpr(const clang::ParenExpr *p) {
+    return this->Visit(p->getSubExpr());
+  }
+
+#define SUPPORTED_UNOP(UNOP) \
+  bool VisitUnary ## UNOP(const clang::UnaryOperator *unop) { \
+    return this->Visit(unop->getSubExpr()); \
+  }
+  SUPPORTED_UNOP(Plus)
+  SUPPORTED_UNOP(Minus)
+  SUPPORTED_UNOP(Not)
+#undef SUPPORTED_UNOP
+
+#define SUPPORTED_BINOP(BINOP) \
+  bool VisitBin ## BINOP(const clang::BinaryOperator *binop) { \
+    return this->Visit(binop->getLHS()) && this->Visit(binop->getRHS()); \
+  }
+  SUPPORTED_BINOP(Add)
+  SUPPORTED_BINOP(Sub)
+  SUPPORTED_BINOP(Div)
+  SUPPORTED_BINOP(Mul)
+  SUPPORTED_BINOP(Rem)
+  SUPPORTED_BINOP(Shl)
+  SUPPORTED_BINOP(Shr)
+  SUPPORTED_BINOP(And)
+  SUPPORTED_BINOP(Xor)
+  SUPPORTED_BINOP(Or)
+#undef SUPPORTED_BINOP
+
+  bool VisitStmt(const clang::Stmt *) { return false; }
+};
+} // namespace
+
+// Don't try to transform any Swift types that _SwiftifyImport doesn't know how
+// to handle.
+static bool SwiftifiableCountedByPointerType(Type swiftType) {
+  Type nonnullType = swiftType->lookThroughSingleOptionalType();
+  PointerTypeKind PTK;
+  return nonnullType->getAnyPointerElementType(PTK) &&
+    (PTK == PTK_UnsafePointer || PTK == PTK_UnsafeMutablePointer);
+}
+static bool SwiftifiableSizedByPointerType(const clang::ASTContext &ctx,
+                                           Type swiftType,
+                                           const clang::CountAttributedType *CAT) {
+  Type nonnullType = swiftType->lookThroughSingleOptionalType();
+  if (nonnullType->isOpaquePointer())
+    return true;
+  PointerTypeKind PTK;
+  if (!nonnullType->getAnyPointerElementType(PTK))
+    return false;
+  if (PTK == PTK_UnsafeRawPointer || PTK == PTK_UnsafeMutableRawPointer)
+    return true;
+  if (PTK != PTK_UnsafePointer && PTK != PTK_UnsafeMutablePointer)
+    return false;
+  // We have a pointer to a type with a size. Verify that it is char-sized.
+  auto PtrT = CAT->getAs<clang::PointerType>();
+  auto PointeeT = PtrT->getPointeeType();
+  return ctx.getTypeSizeInChars(PointeeT).isOne();
+}
+static bool SwiftifiableCAT(const clang::ASTContext &ctx,
+                            const clang::CountAttributedType *CAT,
+                            Type swiftType) {
+  return CAT && CountedByExpressionValidator().Visit(CAT->getCountExpr()) &&
+    (CAT->isCountInBytes() ?
+       SwiftifiableSizedByPointerType(ctx, swiftType, CAT)
+     : SwiftifiableCountedByPointerType(swiftType));
+}
+
+namespace {
+
+// Searches for template instantiations that are not behind type aliases.
+// FIXME: make sure the generated code compiles for template
+// instantiations that are not behind type aliases.
+struct UnaliasedInstantiationVisitor
+    : clang::RecursiveASTVisitor<UnaliasedInstantiationVisitor> {
+  bool hasUnaliasedInstantiation = false;
+
+  bool TraverseTypedefType(const clang::TypedefType *) { return true; }
+
+  bool
+  VisitTemplateSpecializationType(const clang::TemplateSpecializationType *) {
+    hasUnaliasedInstantiation = true;
+    return false;
+  }
+};
+} // namespace
+
+
+
+void ClangImporter::Implementation::addExplicitProtocolConformance(
+    NominalTypeDecl *decl,
+    clang::SwiftAttrAttr *conformsToAttr,
+    llvm::SmallSet<ProtocolDecl *, 4> &alreadyAdded) {
+  auto conformsToValue = conformsToAttr->getAttribute()
+                             .drop_front(StringRef("conforms_to:").size())
+                             .str();
+  auto names = StringRef(conformsToValue).split('.');
+  auto moduleName = names.first;
+  auto protocolName = names.second;
+  if (protocolName.empty()) {
+    HeaderLoc attrLoc(conformsToAttr->getLocation());
+    diagnose(attrLoc, diag::conforms_to_missing_dot, conformsToValue);
+    return;
+  }
+
+  auto *mod = SwiftContext.getModuleByIdentifier(
+      SwiftContext.getIdentifier(moduleName));
+  if (!mod) {
+    HeaderLoc attrLoc(conformsToAttr->getLocation());
+    diagnose(attrLoc, diag::cannot_find_conforms_to_module,
+             conformsToValue, moduleName);
+    return;
+  }
+
+  SmallVector<ValueDecl *, 1> results;
+  mod->lookupValue(SwiftContext.getIdentifier(protocolName),
+                   NLKind::UnqualifiedLookup, results);
+  if (results.empty()) {
+    HeaderLoc attrLoc(conformsToAttr->getLocation());
+    diagnose(attrLoc, diag::cannot_find_conforms_to, protocolName,
+             moduleName);
+    return;
+  }
+
+  if (results.size() != 1) {
+    HeaderLoc attrLoc(conformsToAttr->getLocation());
+    diagnose(attrLoc, diag::conforms_to_ambiguous, protocolName,
+             moduleName);
+    return;
+  }
+
+  auto result = results.front();
+  if (auto protocol = dyn_cast<ProtocolDecl>(result)) {
+    auto [_, inserted] = alreadyAdded.insert(protocol);
+    if (!inserted) {
+      HeaderLoc attrLoc(conformsToAttr->getLocation());
+      diagnose(attrLoc, diag::redundant_conformance_protocol,
+               decl->getDeclaredInterfaceType(), conformsToValue);
+    }
+
+    decl->getAttrs().add(
+        new (SwiftContext) SynthesizedProtocolAttr(protocol, this, false));
+  } else {
+    HeaderLoc attrLoc((conformsToAttr)->getLocation());
+    diagnose(attrLoc, diag::conforms_to_not_protocol, result,
+             conformsToValue);
+  }
+}
+
+void ClangImporter::Implementation::addExplicitProtocolConformancesFromBases(
+    NominalTypeDecl *nominal,
+    const clang::CXXRecordDecl *cxxRecordDecl,
+    bool isBase) {
+  if (cxxRecordDecl->isCompleteDefinition()) {
+    // Propagate conforms_to attribute from public base classes.
+    for (auto base : cxxRecordDecl->bases()) {
+      if (base.getAccessSpecifier() != clang::AccessSpecifier::AS_public)
+        continue;
+      if (auto *baseClangDecl = base.getType()->getAsCXXRecordDecl())
+        addExplicitProtocolConformancesFromBases(nominal, baseClangDecl,
+                                                 /*isBase=*/true);
+    }
+  }
+
+  if (isBase && cxxRecordDecl->hasAttrs()) {
+    llvm::SmallSet<ProtocolDecl *, 4> alreadyAdded;
+    llvm::for_each(cxxRecordDecl->getAttrs(), [&](auto *attr) {
+      if (auto swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr)) {
+        if (swiftAttr->getAttribute().starts_with("conforms_to:"))
+          addExplicitProtocolConformance(nominal, swiftAttr, alreadyAdded);
+      }
+    });
+  }
+}
+
+void ClangImporter::Implementation::addOptionSetTypealiases(
+    NominalTypeDecl *nominal) {
+  auto selfType = nominal->getDeclaredInterfaceType();
+  addSynthesizedTypealias(nominal, SwiftContext.Id_Element, selfType);
+  addSynthesizedTypealias(nominal, SwiftContext.Id_ArrayLiteralElement,
+                          selfType);
+}
+
+#define SIW_DBG(x) DEBUG_WITH_TYPE("safe-interop-wrappers", llvm::dbgs() << x)
+
+// until CountAttributedType::getAttributeName lands in our LLVM branch
+static StringRef getAttributeName(const clang::CountAttributedType *CAT) {
+  switch (CAT->getKind()) {
+    case clang::CountAttributedType::CountedBy:
+      return "__counted_by";
+    case clang::CountAttributedType::CountedByOrNull:
+      return "__counted_by_or_null";
+    case clang::CountAttributedType::SizedBy:
+      return "__sized_by";
+    case clang::CountAttributedType::SizedByOrNull:
+      return "__sized_by_or_null";
+    case clang::CountAttributedType::EndedBy:
+      llvm_unreachable("CountAttributedType cannot be ended_by");
+  }
+}
+
+void ClangImporter::Implementation::swiftify(AbstractFunctionDecl *MappedDecl) {
   if (!SwiftContext.LangOpts.hasFeature(Feature::SafeInteropWrappers))
     return;
   auto ClangDecl =
       dyn_cast_or_null<clang::FunctionDecl>(MappedDecl->getClangDecl());
   if (!ClangDecl)
     return;
+  SIW_DBG("Checking " << *ClangDecl << " for bounds and lifetime info\n");
+
+  // FIXME: for private macro generated functions we do not serialize the
+  // SILFunction's body anywhere triggering assertions.
+  if (ClangDecl->getAccess() == clang::AS_protected ||
+      ClangDecl->getAccess() == clang::AS_private)
+    return;
+
+  MacroDecl *SwiftifyImportDecl = dyn_cast_or_null<MacroDecl>(getKnownSingleDecl(SwiftContext, "_SwiftifyImport"));
+  if (!SwiftifyImportDecl)
+    return;
+
+  {
+    UnaliasedInstantiationVisitor visitor;
+    visitor.TraverseType(ClangDecl->getType());
+    if (visitor.hasUnaliasedInstantiation)
+      return;
+  }
 
   llvm::SmallString<128> MacroString;
   // We only attach the macro if it will produce an overload. Any __counted_by
@@ -9003,56 +9530,130 @@ void ClangImporter::Implementation::swiftify(FuncDecl *MappedDecl) {
           }
           return false;
         };
-    SwiftifyInfoPrinter printer(getClangASTContext(), out);
+    SwiftifyInfoPrinter printer(getClangASTContext(), SwiftContext, out, *SwiftifyImportDecl);
+    Type swiftReturnTy;
+    if (const auto *funcDecl = dyn_cast<FuncDecl>(MappedDecl))
+      swiftReturnTy = funcDecl->getResultInterfaceType();
+    else if (const auto *ctorDecl = dyn_cast<ConstructorDecl>(MappedDecl))
+      swiftReturnTy = ctorDecl->getResultInterfaceType();
+    else
+      ABORT("Unexpected AbstractFunctionDecl subclass.");
     bool returnIsStdSpan = registerStdSpanTypeMapping(
-        MappedDecl->getResultInterfaceType(), ClangDecl->getReturnType());
-    if (auto CAT =
-            ClangDecl->getReturnType()->getAs<clang::CountAttributedType>()) {
+        swiftReturnTy, ClangDecl->getReturnType());
+    auto *CAT = ClangDecl->getReturnType()->getAs<clang::CountAttributedType>();
+    if (SwiftifiableCAT(getClangASTContext(), CAT, swiftReturnTy)) {
       printer.printCountedBy(CAT, SwiftifyInfoPrinter::RETURN_VALUE_INDEX);
+      SIW_DBG("  Found bounds info '" << clang::QualType(CAT, 0) << "' on return value\n");
       attachMacro = true;
     }
     bool returnHasLifetimeInfo = false;
     if (SwiftDeclConverter::getImplicitObjectParamAnnotation<
             clang::LifetimeBoundAttr>(ClangDecl)) {
+      SIW_DBG("  Found lifetimebound attribute on implicit 'this'\n");
       printer.printLifetimeboundReturn(SwiftifyInfoPrinter::SELF_PARAM_INDEX,
                                        true);
       returnHasLifetimeInfo = true;
     }
+
+    bool isClangInstanceMethod =
+        isa<clang::CXXMethodDecl>(ClangDecl) &&
+        !isa<clang::CXXConstructorDecl>(ClangDecl) &&
+        cast<clang::CXXMethodDecl>(ClangDecl)->isInstance();
+    size_t swiftNumParams = MappedDecl->getParameters()->size() -
+                            (ClangDecl->isVariadic() ? 1 : 0);
+    ASSERT((MappedDecl->isImportAsInstanceMember() == isClangInstanceMethod) ==
+           (ClangDecl->getNumParams() == swiftNumParams));
+
+    size_t selfParamIndex = MappedDecl->isImportAsInstanceMember()
+                                ? MappedDecl->getSelfIndex()
+                                : ClangDecl->getNumParams();
     for (auto [index, clangParam] : llvm::enumerate(ClangDecl->parameters())) {
       auto clangParamTy = clangParam->getType();
-      auto swiftParam = MappedDecl->getParameters()->get(index);
+      int mappedIndex = index < selfParamIndex ? index :
+        index > selfParamIndex ? index - 1 :
+        SwiftifyInfoPrinter::SELF_PARAM_INDEX;
+      ParamDecl *swiftParam = nullptr;
+      if (mappedIndex == SwiftifyInfoPrinter::SELF_PARAM_INDEX) {
+        swiftParam = MappedDecl->getImplicitSelfDecl(/*createIfNeeded*/true);
+      } else {
+        swiftParam = MappedDecl->getParameters()->get(mappedIndex);
+      }
+      ASSERT(swiftParam);
+      Type swiftParamTy = swiftParam->getInterfaceType();
       bool paramHasBoundsInfo = false;
-      if (auto CAT = clangParamTy->getAs<clang::CountAttributedType>()) {
-        printer.printCountedBy(CAT, index);
+      auto *CAT = clangParamTy->getAs<clang::CountAttributedType>();
+      if (CAT && mappedIndex == SwiftifyInfoPrinter::SELF_PARAM_INDEX) {
+        diagnose(HeaderLoc(clangParam->getLocation()),
+                 diag::warn_clang_ignored_bounds_on_self, getAttributeName(CAT));
+        auto swiftName = ClangDecl->getAttr<clang::SwiftNameAttr>();
+        ASSERT(swiftName &&
+               "free function mapped to instance method without swift_name??");
+        diagnose(HeaderLoc(swiftName->getLocation()),
+                 diag::note_swift_name_instance_method);
+      } else if (SwiftifiableCAT(getClangASTContext(), CAT, swiftParamTy)) {
+        printer.printCountedBy(CAT, mappedIndex);
+        SIW_DBG("  Found bounds info '" << clangParamTy
+                << "' on parameter '" << *clangParam << "'\n");
         attachMacro = paramHasBoundsInfo = true;
       }
       bool paramIsStdSpan = registerStdSpanTypeMapping(
-          swiftParam->getInterfaceType(), clangParamTy);
+          swiftParamTy, clangParamTy);
       paramHasBoundsInfo |= paramIsStdSpan;
 
       bool paramHasLifetimeInfo = false;
       if (clangParam->hasAttr<clang::NoEscapeAttr>()) {
-        printer.printNonEscaping(index);
+        SIW_DBG("  Found noescape attribute on parameter '" << *clangParam << "'\n");
+        printer.printNonEscaping(mappedIndex);
         paramHasLifetimeInfo = true;
       }
       if (clangParam->hasAttr<clang::LifetimeBoundAttr>()) {
-        printer.printLifetimeboundReturn(
-            index, !paramHasBoundsInfo &&
-                       swiftParam->getInterfaceType()->isEscapable());
+        SIW_DBG("  Found lifetimebound attribute on parameter '"
+                        << *clangParam << "'\n");
+        // If this parameter has bounds info we will tranform it into a Span,
+        // so then it will no longer be Escapable.
+        bool willBeEscapable = swiftParamTy->isEscapable() &&
+            (!paramHasBoundsInfo ||
+             mappedIndex == SwiftifyInfoPrinter::SELF_PARAM_INDEX);
+        printer.printLifetimeboundReturn(mappedIndex, willBeEscapable);
         paramHasLifetimeInfo = true;
         returnHasLifetimeInfo = true;
       }
-      if (paramIsStdSpan && paramHasLifetimeInfo)
+      if (paramIsStdSpan && paramHasLifetimeInfo) {
+        SIW_DBG("  Found both std::span and lifetime info "
+                        "for parameter '" << *clangParam << "'\n");
         attachMacro = true;
+      }
     }
-    if (returnIsStdSpan && returnHasLifetimeInfo)
+    if (returnIsStdSpan && returnHasLifetimeInfo) {
+      SIW_DBG("  Found both std::span and lifetime info for return value\n");
       attachMacro = true;
+    }
+    printer.printAvailability();
     printer.printTypeMapping(typeMapping);
   }
 
-  if (attachMacro)
-    importNontrivialAttribute(MappedDecl, MacroString);
+  if (attachMacro) {
+    SIW_DBG("Attaching safe interop macro: " << MacroString << "\n");
+    if (clang::RawComment *raw =
+            getClangASTContext().getRawCommentForDeclNoCache(ClangDecl)) {
+      // swift::RawDocCommentAttr doesn't contain its text directly, but instead
+      // references the source range of the parsed comment. Instead of creating
+      // a new source file just to parse the doc comment, we can add the
+      // comment to the macro invocation attribute, which the macro has access
+      // to. Waiting until we know that the macro will be attached before
+      // emitting the comment to the string, despite the comment occurring
+      // first, avoids copying a bunch of potentially long comments for nodes
+      // that don't end up with wrappers.
+      auto commentString =
+          raw->getRawText(getClangASTContext().getSourceManager());
+      importNontrivialAttribute(MappedDecl,
+                                (commentString + "\n" + MacroString).str());
+    } else {
+      importNontrivialAttribute(MappedDecl, MacroString);
+    }
+  }
 }
+#undef SIW_DBG
 
 static bool isUsingMacroName(clang::SourceManager &SM,
                              clang::SourceLocation loc,
@@ -9069,6 +9670,72 @@ static bool isUsingMacroName(clang::SourceManager &SM,
   return content == MacroName;
 }
 
+static void filterUsableVersionedAttrs(
+    const clang::NamedDecl *clangDecl, llvm::VersionTuple currentVersion,
+    std::set<clang::SwiftVersionedAdditionAttr *> &applicableVersionedAttrSet) {
+  // Scan through Swift-Versioned clang attributes and select which one to apply
+  // if multiple candidates exist.
+  SmallVector<clang::SwiftVersionedAdditionAttr *, 4> swiftVersionedAttributes;
+  for (auto attr : clangDecl->attrs())
+    if (auto versionedAttr = dyn_cast<clang::SwiftVersionedAdditionAttr>(attr))
+      swiftVersionedAttributes.push_back(versionedAttr);
+
+  // An attribute version is valid to apply if it is greater than the current
+  // version or is unversioned
+  auto applicableVersion =
+      [currentVersion](clang::VersionTuple attrVersion) -> bool {
+    return attrVersion.empty() || attrVersion >= currentVersion;
+  };
+
+  // We have a better attribute option if there exists another versioned attr
+  // wrapper for this attribute kind with a valid version that is lower than the
+  // one of the attribute we are considering
+  auto haveBetterAttr = [swiftVersionedAttributes, applicableVersion](
+                            clang::VersionTuple attrVersion,
+                            clang::attr::Kind attrKind) -> bool {
+    for (auto VAI = swiftVersionedAttributes.begin(),
+              VAE = swiftVersionedAttributes.end();
+         VAI != VAE; ++VAI) {
+      auto otherVersionedAttr = *VAI;
+      auto otherAttrKind = otherVersionedAttr->getAdditionalAttr()->getKind();
+      auto otherAttrVersion = otherVersionedAttr->getVersion();
+      // Same exact attribute, ignore
+      if (otherAttrKind == attrKind && otherAttrVersion == attrVersion)
+        continue;
+
+      // For a matching attribute kind, an un-versioned attribute
+      // never takes precedence over an exsiting valid versioned one.
+      if (otherAttrKind == attrKind && !attrVersion.empty() &&
+          otherAttrVersion.empty())
+        continue;
+      if (otherAttrKind == attrKind && applicableVersion(otherAttrVersion) &&
+          attrVersion.empty())
+        return true;
+
+      // For two versioned attributes of the same kind, the one with the lower
+      // applicable version takes precedence.
+      if (otherAttrKind == attrKind && applicableVersion(otherAttrVersion) &&
+          otherAttrVersion < attrVersion)
+        return true;
+    }
+    return false;
+  };
+
+  for (auto VAI = swiftVersionedAttributes.begin(),
+            VAE = swiftVersionedAttributes.end();
+       VAI != VAE; ++VAI) {
+    auto versionedAttr = *VAI;
+    auto attrKind = versionedAttr->getAdditionalAttr()->getKind();
+    auto attrVersion = versionedAttr->getVersion();
+    if (!applicableVersion(attrVersion))
+      continue;
+    else if (haveBetterAttr(attrVersion, attrKind))
+      continue;
+    else
+      applicableVersionedAttrSet.insert(versionedAttr);
+  }
+}
+
 void ClangImporter::Implementation::importAttributesFromClangDeclToSynthesizedSwiftDecl(Decl *sourceDecl, Decl* synthesizedDecl)
 {
   // sourceDecl->getClangDecl() can be null because some lazily instantiated cases like C++ members that were instantiated from using-shadow-decls have no corresponding Clang decl.
@@ -9261,7 +9928,7 @@ void ClangImporter::Implementation::importAttributes(
       declContext->lookupAvailabilityDomains(domainIdentifier, results);
 
       if (results.size() > 0) {
-        // FIXME: [availability] Diagnose ambiguous availabilty domain name?
+        // FIXME: [availability] Diagnose ambiguous availability domain name?
         auto AttrKind = avail->getUnavailable()
                             ? AvailableAttr::Kind::Unavailable
                             : AvailableAttr::Kind::Default;
@@ -9379,6 +10046,76 @@ void ClangImporter::Implementation::importAttributes(
   }
 }
 
+static void applyTypeAndNullabilityAPINotes(
+    const clang::NamedDecl *ClangDecl, clang::Sema &Sema,
+    const ImportNameVersion CurrentImporterVersion) {
+  // When importing from a module built with version-independent APINotes
+  // payload, the decl will carry all possible versioned notes, without directly
+  // applying any of them. For "type" and "nullability" notes, we must apply
+  // them first, here, since they change the actual type of the decl as seen
+  // downstream.
+  //
+  // Other kinds of notes will be handled in `importAttributes`.
+  for (clang::NamedDecl::attr_iterator AI = ClangDecl->attr_begin(),
+                                       AE = ClangDecl->attr_end();
+       AI != AE; ++AI) {
+    if (!isa<clang::SwiftTypeAttr>(*AI) &&
+        !isa<clang::SwiftNullabilityAttr>(*AI))
+      continue;
+
+    // Apply Type APINotes
+    if (auto typeRenameAttr = dyn_cast<clang::SwiftTypeAttr>(*AI)) {
+      Sema.ApplyAPINotesType(const_cast<clang::NamedDecl *>(ClangDecl),
+                             typeRenameAttr->getTypeString());
+    }
+
+    // Apply Nullability APINotes
+    if (auto nullabilityAttr = dyn_cast<clang::SwiftNullabilityAttr>(*AI)) {
+      clang::NullabilityKind nullability;
+      switch (nullabilityAttr->getKind()) {
+      case clang::SwiftNullabilityAttr::Kind::NonNull:
+        nullability = clang::NullabilityKind::NonNull;
+        break;
+      case clang::SwiftNullabilityAttr::Kind::Nullable:
+        nullability = clang::NullabilityKind::Nullable;
+        break;
+      case clang::SwiftNullabilityAttr::Kind::Unspecified:
+        nullability = clang::NullabilityKind::Unspecified;
+        break;
+      case clang::SwiftNullabilityAttr::Kind::NullableResult:
+        nullability = clang::NullabilityKind::NullableResult;
+        break;
+      }
+
+      Sema.ApplyNullability(const_cast<clang::NamedDecl *>(ClangDecl),
+                            nullability);
+    }
+  }
+}
+
+static void canonicalizeVersionedSwiftAttributes(
+    const clang::NamedDecl *ClangDecl,
+    const ImportNameVersion CurrentImporterVersion) {
+  if (!ClangDecl->hasAttrs())
+    return;
+
+  // Filter out only the versioned attributes which apply to the
+  // current compilation's language version
+  std::set<clang::SwiftVersionedAdditionAttr *> applicableVersionedAttrSet;
+  filterUsableVersionedAttrs(ClangDecl,
+                             CurrentImporterVersion.asClangVersionTuple(),
+                             applicableVersionedAttrSet);
+
+  // Drop all versioned addition attributes and re-add
+  // above-filtered out applicable attributes in a non-versioned
+  // form in order to ensure all downstream clients
+  // get the expected attribute view.
+  auto mutableDecl = const_cast<clang::NamedDecl *>(ClangDecl);
+  mutableDecl->dropAttrs<clang::SwiftVersionedAdditionAttr>();
+  for (const auto &attr : applicableVersionedAttrSet)
+    mutableDecl->addAttr(attr->getAdditionalAttr());
+}
+
 Decl *
 ClangImporter::Implementation::importDeclImpl(const clang::NamedDecl *ClangDecl,
                                               ImportNameVersion version,
@@ -9390,6 +10127,21 @@ ClangImporter::Implementation::importDeclImpl(const clang::NamedDecl *ClangDecl,
   if (ClangDecl->isInvalidDecl())
     return nullptr;
 
+  // If '-version-independent-apinotes' is used, the `ClangDecl`
+  // will be carrying various APINotes-sourced attributes wrapped
+  // in `SwiftVersionedAdditionAttr`. Filter out which ones are applicable
+  // for the current compilation version and rewrite the set of versioned
+  // attributes with the corresponding subset of only applicable wrapped
+  // attributes.
+  if (SwiftContext.ClangImporterOpts.LoadVersionIndependentAPINotes) {
+    canonicalizeVersionedSwiftAttributes(ClangDecl, CurrentVersion);
+    // When '-version-independent-apinotes' is used, "type" and "nullability"
+    // notes are applied by the client (Importer) instead of the producer of the
+    // Clang module we are consuming. Do so now, early, since these notes
+    // affect the decl's type and require mutation.
+    applyTypeAndNullabilityAPINotes(ClangDecl, getClangSema(), CurrentVersion);
+  }
+
   bool SkippedOverTypedef = false;
   Decl *Result = nullptr;
   if (auto *UnderlyingDecl = canSkipOverTypedef(*this, ClangDecl,
@@ -9397,7 +10149,7 @@ ClangImporter::Implementation::importDeclImpl(const clang::NamedDecl *ClangDecl,
     Result = importDecl(UnderlyingDecl, version);
     SkippedOverTypedef = true;
   }
-  
+
   if (!Result) {
     SwiftDeclConverter converter(*this, version);
     Result = converter.Visit(ClangDecl);
@@ -9530,8 +10282,8 @@ void ClangImporter::Implementation::startedImportingEntity() {
 }
 
 /// Look up associated type requirements in the conforming type.
-static void finishTypeWitnesses(
-    NormalProtocolConformance *conformance) {
+static void finishTypeWitnesses(NormalProtocolConformance *conformance,
+                                ASTContext &ctx) {
   auto *dc = conformance->getDeclContext();
   auto nominal = dc->getSelfNominalTypeDecl();
 
@@ -9565,12 +10317,21 @@ static void finishTypeWitnesses(
       break;
     }
 
+    if (!satisfied && assocType->hasDefaultDefinitionType()) {
+      auto defaultType = assocType->getDefaultDefinitionType();
+      auto subMap =
+          selfType->getContextSubstitutionMap(assocType->getDeclContext());
+      defaultType = defaultType.subst(subMap);
+      conformance->setTypeWitness(assocType, defaultType, assocType);
+      satisfied = true;
+    }
+
     if (!satisfied) {
-      llvm::errs() << ("Cannot look up associated type for "
-                        "imported conformance:\n");
-      conformance->getType().dump(llvm::errs());
-      assocType->dump(llvm::errs());
-      abort();
+      // Avoid compiler crash due to missing witness.
+      conformance->setTypeWitness(assocType, ErrorType::get(ctx), assocType);
+      proto->diagnose(diag::type_does_not_conform, selfType,
+                      proto->getDeclaredType());
+      proto->diagnose(diag::no_witnesses_type, assocType);
     }
   }
 }
@@ -9618,7 +10379,7 @@ void ClangImporter::Implementation::finishNormalConformance(
   auto *proto = conformance->getProtocol();
   PrettyStackTraceConformance trace("completing import of", conformance);
 
-  finishTypeWitnesses(conformance);
+  finishTypeWitnesses(conformance, SwiftContext);
 
   // Imported conformances to @objc protocols also require additional
   // initialization to complete the requirement to witness mapping.
@@ -9881,7 +10642,8 @@ ClangImporter::Implementation::importDeclForDeclContext(
 DeclContext *
 ClangImporter::Implementation::importDeclContextOf(
   const clang::Decl *decl,
-  EffectiveClangContext context)
+  EffectiveClangContext context,
+  bool allowForwardDeclaration)
 {
   DeclContext *importedDC = nullptr;
   switch (context.getKind()) {
@@ -9898,7 +10660,7 @@ ClangImporter::Implementation::importDeclContextOf(
       // Treat friend decls like top-level decls.
       if (functionDecl->getFriendObjectKind()) {
         // Find the top-level decl context.
-        while (isa<clang::NamedDecl>(dc))
+        while (!dc->isFileContext())
           dc = dc->getParent();
       }
 
@@ -9910,7 +10672,7 @@ ClangImporter::Implementation::importDeclContextOf(
     }
 
     if (dc->isTranslationUnit()) {
-      if (auto *module = getClangModuleForDecl(decl))
+      if (auto *module = getClangModuleForDecl(decl, allowForwardDeclaration))
         return module;
       else
         return nullptr;
@@ -9963,9 +10725,11 @@ ClangImporter::Implementation::importDeclContextOf(
   if (!importedDC) return nullptr;
 
   // If the declaration was not global to start with, we're done.
-  bool isGlobal =
-    decl->getDeclContext()->getRedeclContext()->isTranslationUnit();
-  if (!isGlobal) return importedDC;
+  bool isRenamedGlobal =
+      decl->getDeclContext()->getRedeclContext()->isTranslationUnit() ||
+      (context.getKind() == EffectiveClangContext::UnresolvedContext &&
+          decl->getDeclContext()->getRedeclContext()->isNamespace());
+  if (!isRenamedGlobal) return importedDC;
 
   // If the resulting declaration context is not a nominal type,
   // we're done.
@@ -9985,8 +10749,7 @@ ClangImporter::Implementation::importDeclContextOf(
                                    getClangModuleForDecl(decl), nullptr);
   SwiftContext.evaluator.cacheOutput(ExtendedTypeRequest{ext},
                                      nominal->getDeclaredType());
-  SwiftContext.evaluator.cacheOutput(ExtendedNominalRequest{ext},
-                                     std::move(nominal));
+  ext->setExtendedNominal(nominal);
 
   // Record this extension so we can find it later. We do this early because
   // once we've set the member loader, we don't know when the compiler will use
@@ -10033,6 +10796,22 @@ ValueDecl *ClangImporter::Implementation::createUnavailableDecl(
   return var;
 }
 
+void ClangImporter::Implementation::handleAmbiguousSwiftName(ValueDecl *decl) {
+  if (!decl || decl->isUnavailable())
+    return;
+
+  auto *cxxRecordDecl = dyn_cast<clang::CXXRecordDecl>(
+      decl->getDeclContext()->getAsDecl()->getClangDecl());
+
+  if (!cxxRecordDecl)
+    return;
+
+  if (findUnavailableMethod(cxxRecordDecl, decl->getName())) {
+    markUnavailable(decl,
+                    "overrides multiple C++ methods with different Swift names");
+  }
+}
+
 // Force the members of the entire inheritance hierarchy to be loaded and
 // deserialized before loading the members of this class. This allows the
 // decl members table to be warmed up and enables the correct identification of
@@ -10157,7 +10936,9 @@ void ClangImporter::Implementation::loadAllMembersOfRecordDecl(
   }
 
   // If this is a C++ record, look through the base classes too.
-  if (auto cxxRecord = dyn_cast<clang::CXXRecordDecl>(clangRecord)) {
+  const clang::CXXRecordDecl *cxxRecord;
+  if ((cxxRecord = dyn_cast<clang::CXXRecordDecl>(clangRecord)) &&
+      cxxRecord->isCompleteDefinition()) {
     for (auto base : cxxRecord->bases()) {
       if (skipIfNonPublic && base.getAccessSpecifier() != clang::AS_public)
         continue;
@@ -10265,7 +11046,7 @@ void ClangImporter::Implementation::loadAllMembersIntoExtension(
 
   // Load the members.
   for (auto entry : table->allGlobalsAsMembersInContext(effectiveClangContext)) {
-    auto decl = entry.get<clang::NamedDecl *>();
+    auto decl = cast<clang::NamedDecl *>(entry);
 
     // Only include members in the same submodule as this extension.
     if (getClangSubmoduleForDecl(decl) != submodule)
@@ -10481,9 +11262,8 @@ void ClangImporter::Implementation::loadAllConformances(
       options |= ProtocolConformanceFlags::Unchecked;
 
     auto conformance = SwiftContext.getNormalConformance(
-        dc->getDeclaredInterfaceType(),
-        protocol, SourceLoc(), dc,
-        ProtocolConformanceState::Incomplete,
+        dc->getDeclaredInterfaceType(), protocol, SourceLoc(),
+        /*inheritedTypeRepr=*/nullptr, dc, ProtocolConformanceState::Incomplete,
         options);
     conformance->setLazyLoader(this, /*context*/0);
     conformance->setState(ProtocolConformanceState::Complete);
diff --git a/lib/ClangImporter/ImportEnumInfo.cpp b/lib/ClangImporter/ImportEnumInfo.cpp
index 07dfb6fc5d6ff..dc5c8a0d91709 100644
--- a/lib/ClangImporter/ImportEnumInfo.cpp
+++ b/lib/ClangImporter/ImportEnumInfo.cpp
@@ -244,10 +244,44 @@ StringRef importer::getCommonPluralPrefix(StringRef singular,
 }
 
 const clang::Type *importer::getUnderlyingType(const clang::EnumDecl *decl) {
-  const clang::Type *underlyingType = decl->getIntegerType().getTypePtr();
-  if (auto elaborated = dyn_cast<clang::ElaboratedType>(underlyingType))
-    underlyingType = elaborated->desugar().getTypePtr();
-  return underlyingType;
+  return importer::desugarIfElaborated(decl->getIntegerType().getTypePtr());
+}
+
+ImportedType importer::findOptionSetEnum(clang::QualType type,
+                                         ClangImporter::Implementation &Impl) {
+  auto typedefType = dyn_cast<clang::TypedefType>(type);
+  if (!typedefType || !Impl.isUnavailableInSwift(typedefType->getDecl()))
+    // If this isn't a typedef, or it is a typedef that is available in Swift,
+    // then this definitely isn't used for {CF,NS}_OPTIONS.
+    return ImportedType();
+
+  if (Impl.SwiftContext.LangOpts.EnableCXXInterop &&
+      !isCFOptionsMacro(typedefType->getDecl(), Impl.getClangPreprocessor())) {
+    return ImportedType();
+  }
+
+  auto clangEnum = findAnonymousEnumForTypedef(Impl.SwiftContext, typedefType);
+  if (!clangEnum)
+    return ImportedType();
+
+  // Assert that the typedef has the same underlying integer representation as
+  // the enum we think it assigns a type name to.
+  //
+  // If these fails, it means that we need a stronger predicate for
+  // determining the relationship between an enum and typedef.
+  if (auto *tdEnum =
+          dyn_cast<clang::EnumType>(typedefType->getCanonicalTypeInternal())) {
+    ASSERT(clangEnum.value()->getIntegerType()->getCanonicalTypeInternal() ==
+           tdEnum->getDecl()->getIntegerType()->getCanonicalTypeInternal());
+  } else {
+    ASSERT(clangEnum.value()->getIntegerType()->getCanonicalTypeInternal() ==
+           typedefType->getCanonicalTypeInternal());
+  }
+
+  if (auto *swiftEnum = Impl.importDecl(*clangEnum, Impl.CurrentVersion))
+    return {cast<TypeDecl>(swiftEnum)->getDeclaredInterfaceType(), false};
+
+  return ImportedType();
 }
 
 /// Determine the prefix to be stripped from the names of the enum constants
diff --git a/lib/ClangImporter/ImportEnumInfo.h b/lib/ClangImporter/ImportEnumInfo.h
index 1bffcc76a4b68..bc57675ff4499 100644
--- a/lib/ClangImporter/ImportEnumInfo.h
+++ b/lib/ClangImporter/ImportEnumInfo.h
@@ -19,6 +19,8 @@
 
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/Decl.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Sema/Sema.h"
 #include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/DenseMap.h"
 
@@ -164,14 +166,18 @@ StringRef getCommonPluralPrefix(StringRef singular, StringRef plural);
 /// an elaborated type, an unwrapped type is returned.
 const clang::Type *getUnderlyingType(const clang::EnumDecl *decl);
 
-inline bool isCFOptionsMacro(StringRef macroName) {
-  return llvm::StringSwitch<bool>(macroName)
+inline bool isCFOptionsMacro(const clang::NamedDecl *decl,
+                             clang::Preprocessor &preprocessor) {
+  auto loc = decl->getEndLoc();
+  if (!loc.isMacroID())
+    return false;
+  return llvm::StringSwitch<bool>(preprocessor.getImmediateMacroName(loc))
       .Case("CF_OPTIONS", true)
       .Case("NS_OPTIONS", true)
       .Default(false);
 }
 
-}
-}
+} // namespace importer
+} // namespace swift
 
 #endif // SWIFT_CLANG_IMPORT_ENUM_H
diff --git a/lib/ClangImporter/ImportMacro.cpp b/lib/ClangImporter/ImportMacro.cpp
index 570d55a55fd64..3a089b7e9fa75 100644
--- a/lib/ClangImporter/ImportMacro.cpp
+++ b/lib/ClangImporter/ImportMacro.cpp
@@ -20,6 +20,7 @@
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/DiagnosticsClangImporter.h"
 #include "swift/AST/Expr.h"
+#include "swift/AST/ParameterList.h"
 #include "swift/AST/Stmt.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
@@ -31,6 +32,7 @@
 #include "clang/Lex/MacroInfo.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/DelayedDiagnostic.h"
+#include "clang/Sema/Lookup.h"
 #include "clang/Sema/Sema.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
 #include "llvm/ADT/SmallString.h"
@@ -331,12 +333,16 @@ getIntegerConstantForMacroToken(ClangImporter::Implementation &impl,
     }
 
   // Macro identifier.
-  // TODO: for some reason when in C++ mode, "hasMacroDefinition" is often
-  // false: rdar://110071334
-  } else if (token.is(clang::tok::identifier) &&
-             token.getIdentifierInfo()->hasMacroDefinition()) {
+  } else if (token.is(clang::tok::identifier)) {
 
     auto rawID = token.getIdentifierInfo();
+
+    // When importing in (Objective-)C++ language mode, sometimes a macro might
+    // have an outdated identifier info, which would cause Clang preprocessor to
+    // assume that it does not have a definition.
+    if (rawID->isOutOfDate())
+      (void)impl.getClangPreprocessor().getLeafModuleMacros(rawID);
+
     auto definition = impl.getClangPreprocessor().getMacroDefinition(rawID);
     if (!definition)
       return std::nullopt;
@@ -371,6 +377,107 @@ getIntegerConstantForMacroToken(ClangImporter::Implementation &impl,
   return std::nullopt;
 }
 
+namespace {
+ValueDecl *importDeclAlias(ClangImporter::Implementation &clang,
+                           swift::DeclContext *DC, const clang::ValueDecl *D,
+                           Identifier alias) {
+  if (!DC->getASTContext().LangOpts.hasFeature(Feature::ImportMacroAliases))
+    return nullptr;
+
+  // Variadic functions cannot be imported into Swift.
+  // FIXME(compnerd) emit a diagnostic for the missing diagnostic.
+  if (const auto *FD = dyn_cast<clang::FunctionDecl>(D))
+    if (FD->isVariadic())
+      return nullptr;
+
+  // Ignore self-referential macros.
+  if (D->getName() == alias.str())
+    return nullptr;
+
+  swift::ValueDecl *VD =
+      dyn_cast_or_null<ValueDecl>(clang.importDecl(D, clang.CurrentVersion));
+  if (VD == nullptr)
+    return nullptr;
+
+  // If the imported decl is named identically, avoid the aliasing.
+  if (VD->getBaseIdentifier().str() == alias.str())
+    return nullptr;
+
+  swift::ASTContext &Ctx = DC->getASTContext();
+  ImportedType Ty =
+      clang.importType(D->getType(), ImportTypeKind::Abstract,
+                       [&clang, &D](Diagnostic &&Diag) {
+                         clang.addImportDiagnostic(D, std::move(Diag),
+                                                   D->getLocation());
+                       }, /*AllowsNSUIntegerAsInt*/true,
+                       Bridgeability::None, { });
+  swift::Type GetterTy = FunctionType::get({}, Ty.getType(), ASTExtInfo{});
+  swift::Type SetterTy =
+      FunctionType::get({AnyFunctionType::Param(Ty.getType())},
+                        Ctx.TheEmptyTupleType, ASTExtInfo{});
+
+  /* Storage */
+  swift::VarDecl *V =
+      new (Ctx) VarDecl(/*IsStatic*/false, VarDecl::Introducer::Var,
+                        SourceLoc(), alias, DC);
+  V->setAccess(swift::AccessLevel::Public);
+  V->setInterfaceType(Ty.getType());
+  V->getAttrs().add(new (Ctx) TransparentAttr(/*Implicit*/true));
+  V->getAttrs().add(new (Ctx) InlineAttr(InlineKind::AlwaysUnderscored));
+
+  /* Accessor */
+  swift::AccessorDecl *G = nullptr;
+  {
+    G = AccessorDecl::createImplicit(Ctx, AccessorKind::Get, V, false, false,
+                                     TypeLoc(), GetterTy, DC);
+    G->setAccess(swift::AccessLevel::Public);
+    G->setInterfaceType(GetterTy);
+    G->setIsTransparent(true);
+    G->setParameters(ParameterList::createEmpty(Ctx));
+
+    DeclRefExpr *DRE =
+        new (Ctx) DeclRefExpr(ConcreteDeclRef(VD), {}, /*Implicit*/true,
+                              AccessSemantics::Ordinary, Ty.getType());
+    ReturnStmt *RS = ReturnStmt::createImplicit(Ctx, DRE);
+
+    G->setBody(BraceStmt::createImplicit(Ctx, {RS}),
+               AbstractFunctionDecl::BodyKind::TypeChecked);
+  }
+
+  swift::AccessorDecl *S = nullptr;
+  if (isa<clang::VarDecl>(D) &&
+      !cast<clang::VarDecl>(D)->getType().isConstQualified()) {
+    S = AccessorDecl::createImplicit(Ctx, AccessorKind::Set, V, false, false,
+                                     TypeLoc(), Ctx.TheEmptyTupleType, DC);
+    S->setAccess(swift::AccessLevel::Public);
+    S->setInterfaceType(SetterTy);
+    S->setIsTransparent(true);
+    S->setParameters(ParameterList::create(Ctx, {
+      ParamDecl::createImplicit(Ctx, Identifier(), Ctx.getIdentifier("newValue"),
+                                Ty.getType(), DC)
+    }));
+
+    DeclRefExpr *LHS =
+        new (Ctx) DeclRefExpr(ConcreteDeclRef(VD), {}, /*Implicit*/true,
+                              AccessSemantics::Ordinary, Ty.getType());
+    DeclRefExpr *RHS =
+        new (Ctx) DeclRefExpr(S->getParameters()->get(0), {}, /*Implicit*/true,
+                              AccessSemantics::Ordinary, Ty.getType());
+    AssignExpr *AE = new (Ctx) AssignExpr(LHS, SourceLoc(), RHS, true);
+    AE->setType(Ctx.TheEmptyTupleType);
+    S->setBody(BraceStmt::createImplicit(Ctx, {AE}),
+               AbstractFunctionDecl::BodyKind::TypeChecked);
+  }
+
+  /* Bind */
+  V->setImplInfo(S ? StorageImplInfo::getMutableComputed()
+                   : StorageImplInfo::getImmutableComputed());
+  V->setAccessors(SourceLoc(), S ? ArrayRef{G,S} : ArrayRef{G}, SourceLoc());
+
+  return V;
+}
+}
+
 static ValueDecl *importMacro(ClangImporter::Implementation &impl,
                               llvm::SmallSet<StringRef, 4> &visitedMacros,
                               DeclContext *DC, Identifier name,
@@ -509,7 +616,14 @@ static ValueDecl *importMacro(ClangImporter::Implementation &impl,
         }
       }
 
-      // FIXME: If the identifier refers to a declaration, alias it?
+      /* Create an alias for any Decl */
+      clang::Sema &S = impl.getClangSema();
+      clang::LookupResult R(S, {{tok.getIdentifierInfo()}, {}},
+                            clang::Sema::LookupAnyName);
+      if (S.LookupName(R, S.TUScope))
+        if (R.getResultKind() == clang::LookupResultKind::Found)
+          if (const auto *VD = dyn_cast<clang::ValueDecl>(R.getFoundDecl()))
+            return importDeclAlias(impl, DC, VD, name);
     }
 
     // TODO(https://github.com/apple/swift/issues/57735): Seems rare to have a single token that is neither a literal nor an identifier, but add diagnosis.
diff --git a/lib/ClangImporter/ImportName.cpp b/lib/ClangImporter/ImportName.cpp
index ba072a640b6ad..b74ef5085924a 100644
--- a/lib/ClangImporter/ImportName.cpp
+++ b/lib/ClangImporter/ImportName.cpp
@@ -18,6 +18,7 @@
 #include "CFTypeInfo.h"
 #include "ClangClassTemplateNamePrinter.h"
 #include "ClangDiagnosticConsumer.h"
+#include "ImportEnumInfo.h"
 #include "ImporterImpl.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ClangSwiftTypeCorrespondence.h"
@@ -645,9 +646,12 @@ findSwiftNameAttr(const clang::Decl *decl, ImportNameVersion version) {
   if (version > ImportNameVersion::swift2()) {
     // FIXME: Until Apple gets a chance to update UIKit's API notes, always use
     // the new name for certain properties.
-    if (auto *namedDecl = dyn_cast<clang::NamedDecl>(decl))
+    if (auto *namedDecl = dyn_cast<clang::NamedDecl>(decl)) {
       if (importer::isSpecialUIKitStructZeroProperty(namedDecl))
         version = ImportNameVersion::swift4_2();
+      if (importer::isSpecialAppKitFunctionKeyProperty(namedDecl))
+        return std::nullopt;
+    }
 
     // Dig out the attribute that specifies the Swift name.
     std::optional<AnySwiftNameAttr> activeAttr;
@@ -1530,6 +1534,15 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
   if (isa<clang::ObjCCategoryDecl>(D))
     return ImportedName();
 
+  // C++ interop was not available in Swift 2
+  if (!swift3OrLaterName && isa<clang::CXXMethodDecl>(D)) {
+    return ImportedName();
+  }
+  // If this function uses C++23 deducing this, bail.
+  if (auto functionDecl = dyn_cast<clang::FunctionDecl>(D))
+    if (functionDecl->hasCXXExplicitFunctionObjectParameter())
+      return {};
+
   // Dig out the definition, if there is one.
   if (auto def = getDefinitionForClangTypeDecl(D)) {
     if (*def)
@@ -1700,6 +1713,12 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
       }
     }
 
+    // `swift_name` attribute is not supported in virtual methods overrides
+    if (auto method = dyn_cast<clang::CXXMethodDecl>(D)) {
+      if (method->isVirtual() && method->size_overridden_methods() > 0)
+        skipCustomName = true;
+    }
+
     if (!skipCustomName) {
       result.info.hasCustomName = true;
       result.declName = parsedName.formDeclName(
@@ -1877,15 +1896,9 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
   // imported into Swift to avoid having two types with the same name, which
   // cause subtle name lookup issues.
   if (swiftCtx.LangOpts.EnableCXXInterop &&
-      isUnavailableInSwift(D, nullptr, true)) {
-    auto loc = D->getEndLoc();
-    if (loc.isMacroID()) {
-      StringRef macroName =
-          clangSema.getPreprocessor().getImmediateMacroName(loc);
-      if (isCFOptionsMacro(macroName))
-        return ImportedName();
-    }
-  }
+      isUnavailableInSwift(D, nullptr, true) &&
+      isCFOptionsMacro(D, clangSema.getPreprocessor()))
+    return ImportedName();
 
   /// Whether the result is a function name.
   bool isFunction = false;
@@ -1955,6 +1968,7 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
     case clang::OverloadedOperatorKind::OO_Caret:
     case clang::OverloadedOperatorKind::OO_Amp:
     case clang::OverloadedOperatorKind::OO_Pipe:
+    case clang::OverloadedOperatorKind::OO_Tilde:
     case clang::OverloadedOperatorKind::OO_Exclaim:
     case clang::OverloadedOperatorKind::OO_Less:
     case clang::OverloadedOperatorKind::OO_Greater:
@@ -1967,6 +1981,14 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
     case clang::OverloadedOperatorKind::OO_GreaterEqual:
     case clang::OverloadedOperatorKind::OO_AmpAmp:
     case clang::OverloadedOperatorKind::OO_PipePipe: {
+      // If the operator has a parameter that is an rvalue reference, it would
+      // cause name lookup collision with an overload that has lvalue reference
+      // parameter, if it exists.
+      for (auto paramDecl : functionDecl->parameters()) {
+        if (paramDecl->getType()->isRValueReferenceType())
+          return ImportedName();
+      }
+
       auto operatorName =
           isa<clang::CXXMethodDecl>(functionDecl)
               ? getOperatorName(swiftCtx, op)
@@ -2266,11 +2288,6 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
 
   if (auto classTemplateSpecDecl =
           dyn_cast<clang::ClassTemplateSpecializationDecl>(D)) {
-    /// Symbolic specializations get imported as the symbolic class template
-    /// type.
-    if (importSymbolicCXXDecls)
-      return importNameImpl(classTemplateSpecDecl->getSpecializedTemplate(),
-                            version, givenName);
     if (!isa<clang::ClassTemplatePartialSpecializationDecl>(D)) {
       auto name = printClassTemplateSpecializationName(classTemplateSpecDecl,
                                                        swiftCtx, this, version);
@@ -2312,6 +2329,42 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
       newName = baseName.substr(StringRef("__synthesizedVirtualCall_").size());
       baseName = newName;
     }
+    if (method->isVirtual()) {
+      // The name should be imported from the base method
+      if (method->size_overridden_methods() > 0) {
+        DeclName overriddenName;
+        bool foundDivergentMethod = false;
+        for (auto overriddenMethod : method->overridden_methods()) {
+          ImportedName importedName =
+              importName(overriddenMethod, version, givenName);
+          if (!overriddenName) {
+            overriddenName = importedName.getDeclName();
+          } else if (overriddenName.compare(importedName.getDeclName())) {
+            importerImpl->insertUnavailableMethod(method->getParent(),
+                                                  importedName.getDeclName());
+            foundDivergentMethod = true;
+          }
+        }
+
+        if (foundDivergentMethod) {
+          // The method we want to mark as unavailable will be generated
+          // lazily, when we clone the methods from base classes to the derived
+          // class method->getParent().
+          // Since we don't have the actual method here, we store this
+          // information to be accessed when we generate the actual method.
+          importerImpl->insertUnavailableMethod(method->getParent(),
+                                                overriddenName);
+          return ImportedName();
+        }
+
+        baseName = overriddenName.getBaseIdentifier().str();
+        // Also inherit argument names from base method
+        argumentNames.clear();
+        llvm::for_each(overriddenName.getArgumentNames(), [&](Identifier arg) {
+          argumentNames.push_back(arg.str());
+        });
+      }
+    }
   }
 
   // swift_newtype-ed declarations may have common words with the type name
diff --git a/lib/ClangImporter/ImportName.h b/lib/ClangImporter/ImportName.h
index 254a58eb45132..9dde3b56e2631 100644
--- a/lib/ClangImporter/ImportName.h
+++ b/lib/ClangImporter/ImportName.h
@@ -423,8 +423,6 @@ class NameImporter {
   llvm::DenseMap<std::pair<const clang::ObjCInterfaceDecl *, char>,
                  std::unique_ptr<InheritedNameSet>> allProperties;
 
-  bool importSymbolicCXXDecls;
-
   ClangImporter::Implementation *importerImpl;
 
 public:
@@ -432,8 +430,6 @@ class NameImporter {
                clang::Sema &cSema, ClangImporter::Implementation *importerImpl)
       : swiftCtx(ctx), availability(avail), clangSema(cSema),
         enumInfos(clangSema.getPreprocessor()),
-        importSymbolicCXXDecls(
-            ctx.LangOpts.hasFeature(Feature::ImportSymbolicCXXDecls)),
         importerImpl(importerImpl) {}
 
   /// Determine the Swift name for a Clang decl
@@ -498,10 +494,6 @@ class NameImporter {
                             clang::ObjCInterfaceDecl *classDecl,
                             bool forInstance);
 
-  inline void enableSymbolicImportFeature(bool isEnabled) {
-    importSymbolicCXXDecls = isEnabled;
-  }
-
   /// Retrieve a purported custom name even if it is invalid.
   static std::optional<StringRef>
   findCustomName(const clang::Decl *decl, ImportNameVersion version);
diff --git a/lib/ClangImporter/ImportType.cpp b/lib/ClangImporter/ImportType.cpp
index 89921480a0a6a..79d469ff55808 100644
--- a/lib/ClangImporter/ImportType.cpp
+++ b/lib/ClangImporter/ImportType.cpp
@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "CFTypeInfo.h"
+#include "ImportEnumInfo.h"
 #include "ImporterImpl.h"
 #include "SwiftDeclSynthesizer.h"
 #include "swift/ABI/MetadataValues.h"
@@ -75,10 +76,6 @@ bool ClangImporter::Implementation::isOverAligned(const clang::TypeDecl *decl) {
 }
 
 bool ClangImporter::Implementation::isOverAligned(clang::QualType type) {
-  // Do not check type layout for a clang type in symbolic mode as the
-  // type could be a dependent type.
-  if (importSymbolicCXXDecls)
-    return false;
   auto align = getClangASTContext().getTypeAlignInChars(type);
   return align > clang::CharUnits::fromQuantity(MaximumAlignment);
 }
@@ -350,7 +347,7 @@ namespace {
 
       // ARM SVE builtin types that don't have Swift equivalents.
 #define SVE_TYPE(Name, Id, ...) case clang::BuiltinType::Id:
-#include "clang/Basic/AArch64SVEACLETypes.def"
+#include "clang/Basic/AArch64ACLETypes.def"
         return Type();
 
       // PPC SVE builtin types that don't have Swift equivalents.
@@ -368,10 +365,15 @@ namespace {
         return Type();
 
       // AMDGPU builtin types that don't have Swift equivalents.
-#define AMDGPU_TYPE(Name, Id, SingletonId) case clang::BuiltinType::Id:
+#define AMDGPU_TYPE(Name, Id, SingletonId, Width, Align)                       \
+      case clang::BuiltinType::Id:
 #include "clang/Basic/AMDGPUTypes.def"
         return Type();
 
+      // HLSL intangible builtin types that don't have Swift equivalents.
+#define HLSL_INTANGIBLE_TYPE(Name, Id, ...) case clang::BuiltinType::Id:
+#include "clang/Basic/HLSLIntangibleTypes.def"
+        return Type();
       }
 
       llvm_unreachable("Invalid BuiltinType.");
@@ -417,6 +419,26 @@ namespace {
       return Type();
     }
 
+    ImportResult VisitHLSLAttributedResourceType(
+        const clang::HLSLAttributedResourceType *type) {
+      Impl.addImportDiagnostic(
+          type,
+          Diagnostic(diag::unsupported_builtin_type, type->getTypeClassName()),
+          clang::SourceLocation());
+      // FIXME: (?) HLSL types are not supported in Swift.
+      return Type();
+    }
+
+    ImportResult
+    VisitHLSLInlineSpirvType(const clang::HLSLInlineSpirvType *type) {
+      Impl.addImportDiagnostic(
+          type,
+          Diagnostic(diag::unsupported_builtin_type, type->getTypeClassName()),
+          clang::SourceLocation());
+      // FIXME: (?) HLSL types are not supported in Swift.
+      return Type();
+    }
+
     ImportResult
     VisitCountAttributedType(const clang::CountAttributedType *type) {
       return Visit(type->desugar());
@@ -425,17 +447,15 @@ namespace {
     ImportResult VisitDynamicRangePointerType(
         const clang::DynamicRangePointerType *type) {
       // DynamicRangePointerType is a clang type representing a pointer with
-      // an "ended_by" type attribute for -fbounds-safety. For now, we don't
-      // import these into Swift.
-      return Type();
+      // an "ended_by" type attribute for -fbounds-safety.
+      return Visit(type->desugar());
     }
 
     ImportResult VisitValueTerminatedType(
         const clang::ValueTerminatedType *type) {
       // ValueTerminatedType is a clang type representing a pointer with
-      // a "terminated_by" type attribute for -fbounds-safety. For now, we don't
-      // import these into Swift.
-      return Type();
+      // a "terminated_by" type attribute for -fbounds-safety.
+      return Visit(type->desugar());
     }
 
     ImportResult VisitMemberPointerType(const clang::MemberPointerType *type) {
@@ -730,20 +750,45 @@ namespace {
             paramQualType->getPointeeType().isConstQualified())
           paramQualType = paramQualType->getPointeeType();
 
+        // Mark any `sending` parameters if need be.
+        ImportTypeAttrs paramAttributes;
+        if (Impl.SwiftContext.LangOpts.hasFeature(Feature::SendingArgsAndResults)) {
+          getConcurrencyAttrs(Impl.SwiftContext, ImportTypeKind::Parameter,
+                              paramAttributes, paramQualType);
+        }
+
         auto swiftParamTy = Impl.importTypeIgnoreIUO(
             paramQualType, paramImportKind, addImportDiagnostic,
             AllowNSUIntegerAsInt, Bridging, ImportTypeAttrs(), OTK_Optional);
         if (!swiftParamTy)
           return Type();
 
+        ParameterTypeFlags flags;
+        flags = flags.withSending(
+            paramAttributes.contains(ImportTypeAttr::Sending));
+
         // FIXME(https://github.com/apple/swift/issues/45134): If we were walking TypeLocs, we could actually get parameter names.
         // The probably doesn't matter outside of a FuncDecl, which we'll have
         // to special-case, but it's an interesting bit of data loss.
-        params.push_back(FunctionType::Param(swiftParamTy));
+        params.emplace_back(swiftParamTy, Identifier(), flags);
+      }
+
+      // Mark any `sending` result types if need be.
+      auto extInfo = FunctionType::ExtInfo();
+      ImportTypeAttrs resultAttributes;
+      if (Impl.SwiftContext.LangOpts.hasFeature(Feature::SendingArgsAndResults)) {
+        getConcurrencyAttrs(Impl.SwiftContext, ImportTypeKind::Result,
+                            resultAttributes, type->getReturnType());
+
+        const bool sending = resultAttributes.contains(ImportTypeAttr::Sending);
+        extInfo = FunctionType::ExtInfo()
+                           .intoBuilder()
+                           .withSendingResult(sending)
+                           .build();
       }
 
       // Form the function type.
-      return FunctionType::get(params, resultTy, FunctionType::ExtInfo());
+      return FunctionType::get(params, resultTy, extInfo);
     }
 
     ImportResult
@@ -1714,10 +1759,9 @@ void swift::getConcurrencyAttrs(ASTContext &SwiftContext,
                                 ImportTypeKind importKind,
                                 ImportTypeAttrs &attrs, clang::QualType type) {
   bool isMainActor = false;
-  bool isSendable =
-      SwiftContext.LangOpts.hasFeature(Feature::SendableCompletionHandlers) &&
-      importKind == ImportTypeKind::CompletionHandlerParameter;
+  bool isSendable = false;
   bool isNonSendable = false;
+  bool isSending = false;
 
   // Consider only immediate attributes, don't look through the typerefs
   // because they are imported separately.
@@ -1725,18 +1769,25 @@ void swift::getConcurrencyAttrs(ASTContext &SwiftContext,
     if (isMainActorAttr(attr)) {
       isMainActor = true;
       isSendable = true; // MainActor implies Sendable
-    } else if (attr->getAttribute() == "@Sendable")
+    } else if (attr->getAttribute() == "@Sendable") {
       isSendable = true;
-    else if (attr->getAttribute() == "@_nonSendable")
+    } else if (attr->getAttribute() == "@_nonSendable") {
       isNonSendable = true;
+    } else if (attr->getAttribute() == "sending") {
+      isSending = true;
+    }
   });
 
   if (isMainActor)
     attrs |= ImportTypeAttr::MainActor;
   if (isSendable)
     attrs |= ImportTypeAttr::Sendable;
-  if (isNonSendable)
+  if (isNonSendable) {
     attrs -= ImportTypeAttr::Sendable;
+    attrs -= ImportTypeAttr::DefaultsToSendable;
+  }
+  if (isSending)
+    attrs |= ImportTypeAttr::Sending;
 }
 
 ImportedType ClangImporter::Implementation::importType(
@@ -2013,7 +2064,6 @@ class GetSendableType :
     return pass(ty, /*found=*/true);
   }
 
-  NEVER_VISIT(UnresolvedType)
   NEVER_VISIT(PlaceholderType)
   NEVER_VISIT(BuiltinType)
   NEVER_VISIT(BuiltinTupleType)
@@ -2191,16 +2241,14 @@ applyImportTypeAttrs(ImportTypeAttrs attrs, Type type,
     }
   }
 
-  if (attrs.contains(ImportTypeAttr::Sendable)) {
+  if (attrs.contains(ImportTypeAttr::Sendable) ||
+      attrs.contains(ImportTypeAttr::DefaultsToSendable)) {
     bool changed;
     std::tie(type, changed) = GetSendableType(SwiftContext).convert(type);
 
     // Diagnose if we couldn't find a place to add `Sendable` to the type.
     if (!changed) {
       addDiag(Diagnostic(diag::clang_ignored_sendable_attr, type));
-
-      if (attrs.contains(ImportTypeAttr::DefaultsToSendable))
-        addDiag(Diagnostic(diag::clang_param_should_be_implicitly_sendable));
     }
   }
 
@@ -2255,10 +2303,8 @@ ImportedType ClangImporter::Implementation::importFunctionReturnType(
     OptionalityOfReturn = OTK_ImplicitlyUnwrappedOptional;
   }
 
-  clang::QualType returnType = clangDecl->getReturnType();
-  if (auto elaborated =
-          dyn_cast<clang::ElaboratedType>(returnType))
-    returnType = elaborated->desugar();
+  clang::QualType returnType = desugarIfElaborated(clangDecl->getReturnType());
+  returnType = desugarIfBoundsAttributed(returnType);
   // In C interop mode, the return type of library builtin functions
   // like 'memcpy' from headers like 'string.h' drops
   // any nullability specifiers from their return type, and preserves it on the
@@ -2296,19 +2342,9 @@ ImportedType ClangImporter::Implementation::importFunctionReturnType(
           ->isTemplateTypeParmType())
     OptionalityOfReturn = OTK_None;
 
-  if (auto typedefType = dyn_cast<clang::TypedefType>(returnType)) {
-    if (isUnavailableInSwift(typedefType->getDecl())) {
-      if (auto clangEnum = findAnonymousEnumForTypedef(SwiftContext, typedefType)) {
-        // If this fails, it means that we need a stronger predicate for
-        // determining the relationship between an enum and typedef.
-        assert(clangEnum.value()->getIntegerType()->getCanonicalTypeInternal() ==
-               typedefType->getCanonicalTypeInternal());
-        if (auto swiftEnum = importDecl(*clangEnum, CurrentVersion)) {
-          return {cast<TypeDecl>(swiftEnum)->getDeclaredInterfaceType(), false};
-        }
-      }
-    }
-  }
+  ImportedType optionSetEnum = importer::findOptionSetEnum(returnType, *this);
+  if (optionSetEnum)
+    return optionSetEnum;
 
   // Import the underlying result type.
   if (clangDecl) {
@@ -2348,10 +2384,6 @@ findGenericTypeInGenericDecls(ClangImporter::Implementation &impl,
       llvm::find_if(genericParams, [name](GenericTypeParamDecl *generic) {
         return generic->getName().str() == name;
       });
-  // We sometimes are unable compute the exact Swift type
-  // of symbolic declarations. Fallback to using `Any` in that case.
-  if (impl.importSymbolicCXXDecls && genericParamIter == genericParams.end())
-    return impl.SwiftContext.TheAnyType;
   // TODO: once we support generics in class types, replace this with
   // "return nullptr". Once support for template classes, this will need to
   // be updated, though. I'm leaving the assert here to make it easier to
@@ -2376,27 +2408,12 @@ ImportedType ClangImporter::Implementation::importFunctionParamsAndReturnType(
 
   // Only eagerly import the return type if it's not too expensive (the current
   // heuristic for that is if it's not a record type).
-  ImportedType importedType;
   ImportDiagnosticAdder addDiag(*this, clangDecl,
                                 clangDecl->getSourceRange().getBegin());
-  clang::QualType returnType = clangDecl->getReturnType();
-  if (auto elaborated = dyn_cast<clang::ElaboratedType>(returnType))
-    returnType = elaborated->desugar();
-
-  if (auto typedefType = dyn_cast<clang::TypedefType>(returnType)) {
-    if (isUnavailableInSwift(typedefType->getDecl())) {
-      if (auto clangEnum = findAnonymousEnumForTypedef(SwiftContext, typedefType)) {
-        // If this fails, it means that we need a stronger predicate for
-        // determining the relationship between an enum and typedef.
-        assert(clangEnum.value()->getIntegerType()->getCanonicalTypeInternal() ==
-               typedefType->getCanonicalTypeInternal());
-        if (auto swiftEnum = importDecl(*clangEnum, CurrentVersion)) {
-          importedType = {cast<TypeDecl>(swiftEnum)->getDeclaredInterfaceType(),
-                          false};
-        }
-      }
-    }
-  }
+  clang::QualType returnType = desugarIfElaborated(clangDecl->getReturnType());
+  returnType = desugarIfBoundsAttributed(returnType);
+
+  ImportedType importedType = importer::findOptionSetEnum(returnType, *this);
 
   if (auto templateType =
           dyn_cast<clang::TemplateTypeParmType>(returnType)) {
@@ -2452,17 +2469,51 @@ ImportedType ClangImporter::Implementation::importFunctionParamsAndReturnType(
   return {swiftResultTy, importedType.isImplicitlyUnwrapped()};
 }
 
+static bool isParameterContextGlobalActorIsolated(DeclContext *dc,
+                                                  const clang::Decl *parent) {
+  if (getActorIsolationOfContext(dc).isGlobalActor())
+    return true;
+
+  if (!parent->hasAttrs())
+    return false;
+
+  for (const auto *attr : parent->getAttrs()) {
+    if (auto swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr)) {
+      if (isMainActorAttr(swiftAttr))
+        return true;
+    }
+  }
+
+  return false;
+}
+
+static bool isSendableInferenceOnCompletionHandlerParameterAllowed(
+    DeclContext *dc, const clang::Decl *parent) {
+  auto &C = dc->getASTContext();
+  if (!C.LangOpts.hasFeature(Feature::SendableCompletionHandlers))
+    return false;
+
+  return !isParameterContextGlobalActorIsolated(dc, parent);
+}
+
 std::optional<ClangImporter::Implementation::ImportParameterTypeResult>
 ClangImporter::Implementation::importParameterType(
-    const clang::ParmVarDecl *param, OptionalTypeKind optionalityOfParam,
-    bool allowNSUIntegerAsInt, bool isNSDictionarySubscriptGetter,
-    bool paramIsError, bool paramIsCompletionHandler,
+    DeclContext *dc, const clang::Decl *parent, const clang::ParmVarDecl *param,
+    OptionalTypeKind optionalityOfParam, bool allowNSUIntegerAsInt,
+    bool isNSDictionarySubscriptGetter, bool paramIsError,
+    bool paramIsCompletionHandler,
     std::optional<unsigned> completionHandlerErrorParamIndex,
     ArrayRef<GenericTypeParamDecl *> genericParams,
     llvm::function_ref<void(Diagnostic &&)> addImportDiagnosticFn) {
-  auto paramTy = param->getType();
-  if (auto elaborated = dyn_cast<clang::ElaboratedType>(paramTy))
-    paramTy = elaborated->desugar();
+  auto paramTy = desugarIfElaborated(param->getType());
+  paramTy = desugarIfBoundsAttributed(paramTy);
+
+  // If this type has a _Nullable/_Nonnull attribute, drop it, since we already
+  // have that information in optionalityOfParam.
+  if (auto attributedTy = dyn_cast<clang::AttributedType>(paramTy)) {
+    if (attributedTy->getImmediateNullability())
+      clang::AttributedType::stripOuterNullability(paramTy);
+  }
 
   ImportTypeKind importKind = paramIsCompletionHandler
                                   ? ImportTypeKind::CompletionHandlerParameter
@@ -2475,23 +2526,13 @@ ClangImporter::Implementation::importParameterType(
   bool isConsuming = false;
   bool isParamTypeImplicitlyUnwrapped = false;
 
-  // Sometimes we import unavailable typedefs as enums. If that's the case,
-  // use the enum, not the typedef here.
-  if (auto typedefType = dyn_cast<clang::TypedefType>(paramTy.getTypePtr())) {
-    if (isUnavailableInSwift(typedefType->getDecl())) {
-      if (auto clangEnum =
-              findAnonymousEnumForTypedef(SwiftContext, typedefType)) {
-        // If this fails, it means that we need a stronger predicate for
-        // determining the relationship between an enum and typedef.
-        assert(clangEnum.value()
-                   ->getIntegerType()
-                   ->getCanonicalTypeInternal() ==
-               typedefType->getCanonicalTypeInternal());
-        if (auto swiftEnum = importDecl(*clangEnum, CurrentVersion)) {
-          swiftParamTy = cast<TypeDecl>(swiftEnum)->getDeclaredInterfaceType();
-        }
-      }
-    }
+  if (paramIsCompletionHandler &&
+      isSendableInferenceOnCompletionHandlerParameterAllowed(dc, parent)) {
+    attrs |= ImportTypeAttr::DefaultsToSendable;
+  }
+
+  if (auto optionSetEnum = importer::findOptionSetEnum(paramTy, *this)) {
+    swiftParamTy = optionSetEnum.getType();
   } else if (isa<clang::PointerType>(paramTy) &&
              isa<clang::TemplateTypeParmType>(paramTy->getPointeeType())) {
     auto pointeeType = paramTy->getPointeeType();
@@ -2507,6 +2548,17 @@ ClangImporter::Implementation::importParameterType(
                                        pointerKind));
       return std::nullopt;
     }
+    switch (optionalityOfParam) {
+    case OTK_Optional:
+      swiftParamTy = OptionalType::get(swiftParamTy);
+      break;
+    case OTK_ImplicitlyUnwrappedOptional:
+      swiftParamTy = OptionalType::get(swiftParamTy);
+      isParamTypeImplicitlyUnwrapped = true;
+      break;
+    case OTK_None:
+      break;
+    }
   } else if (isa<clang::ReferenceType>(paramTy) &&
              isa<clang::TemplateTypeParmType>(paramTy->getPointeeType())) {
     // We don't support universal reference, bail.
@@ -2696,8 +2748,12 @@ static ParamDecl *getParameterInfo(ClangImporter::Implementation *impl,
   // C++ types taking a reference might return a reference/pointer to a
   // subobject of the referenced storage. In those cases we need to prevent the
   // Swift compiler to pass in a temporary copy to prevent dangling.
-  if (ASTContext.LangOpts.hasFeature(Feature::AddressableParameters) &&
-      !param->getType().isNull() && param->getType()->isReferenceType()) {
+  auto paramContext = param->getDeclContext();
+  if (!param->getType().isNull() && param->getType()->isLValueReferenceType() &&
+      !swiftParamTy->isForeignReferenceType() &&
+      !(isa<clang::FunctionDecl>(paramContext) &&
+        cast<clang::FunctionDecl>(paramContext)->isOverloadedOperator()) &&
+      !isa<clang::ObjCMethodDecl, clang::ObjCContainerDecl>(paramContext)) {
     paramInfo->setAddressable();
   }
 
@@ -2755,8 +2811,6 @@ ParameterList *ClangImporter::Implementation::importFunctionParameterList(
     }
 
     bool knownNonNull = !nonNullArgs.empty() && nonNullArgs[index];
-    // Specialized templates need to match the args/result exactly.
-    knownNonNull |= clangDecl->isFunctionTemplateSpecialization();
 
     // Check nullability of the parameter.
     OptionalTypeKind optionalityOfParam =
@@ -2764,13 +2818,13 @@ ParameterList *ClangImporter::Implementation::importFunctionParameterList(
 
     ImportDiagnosticAdder paramAddDiag(*this, clangDecl, param->getLocation());
 
-    auto swiftParamTyOpt =
-        importParameterType(param, optionalityOfParam, allowNSUIntegerAsInt,
-                            /*isNSDictionarySubscriptGetter=*/false,
-                            /*paramIsError=*/false,
-                            /*paramIsCompletionHandler=*/false,
-                            /*completionHandlerErrorParamIndex=*/std::nullopt,
-                            genericParams, paramAddDiag);
+    auto swiftParamTyOpt = importParameterType(
+        dc, clangDecl, param, optionalityOfParam, allowNSUIntegerAsInt,
+        /*isNSDictionarySubscriptGetter=*/false,
+        /*paramIsError=*/false,
+        /*paramIsCompletionHandler=*/false,
+        /*completionHandlerErrorParamIndex=*/std::nullopt, genericParams,
+        paramAddDiag);
     if (!swiftParamTyOpt) {
       addImportDiagnostic(param,
                           Diagnostic(diag::parameter_type_not_imported, param),
@@ -2859,9 +2913,10 @@ ParameterList *ClangImporter::Implementation::importFunctionParameterList(
   // Estimate locations for the begin and end of parameter list.
   auto begin = clangDecl->getLocation();
   auto end = begin;
-  if (!params.empty()) {
-    begin = params.front()->getBeginLoc();
-    end = params.back()->getEndLoc();
+  auto paramsRange = clangDecl->getParametersSourceRange();
+  if (paramsRange.isValid()) {
+    begin = paramsRange.getBegin();
+    end = paramsRange.getEnd();
   }
   return ParameterList::create(SwiftContext, importSourceLoc(begin), parameters,
                                importSourceLoc(end));
@@ -2932,13 +2987,8 @@ ArgumentAttrs ClangImporter::Implementation::inferDefaultArgument(
           return argumentAttrs;
         }
       }
-      auto loc = typedefDecl->getEndLoc();
-      if (loc.isMacroID()) {
-        StringRef macroName =
-            nameImporter.getClangPreprocessor().getImmediateMacroName(loc);
-        if (isCFOptionsMacro(macroName))
-          return argumentAttrs;
-      }
+      if (isCFOptionsMacro(typedefDecl, nameImporter.getClangPreprocessor()))
+        return argumentAttrs;
     }
   }
 
@@ -3211,26 +3261,8 @@ ImportedType ClangImporter::Implementation::importMethodParamsAndReturnType(
 
   ImportDiagnosticAdder addImportDiag(*this, clangDecl,
                                       clangDecl->getLocation());
-  clang::QualType resultType = clangDecl->getReturnType();
-  if (auto elaborated = dyn_cast<clang::ElaboratedType>(resultType))
-    resultType = elaborated->desugar();
-
-  ImportedType importedType;
-  if (auto typedefType = dyn_cast<clang::TypedefType>(resultType.getTypePtr())) {
-    if (isUnavailableInSwift(typedefType->getDecl())) {
-      if (auto clangEnum = findAnonymousEnumForTypedef(SwiftContext, typedefType)) {
-        // If this fails, it means that we need a stronger predicate for
-        // determining the relationship between an enum and typedef.
-        assert(clangEnum.value()->getIntegerType()->getCanonicalTypeInternal() ==
-               typedefType->getCanonicalTypeInternal());
-        if (auto swiftEnum = importDecl(*clangEnum, CurrentVersion)) {
-          importedType = {cast<TypeDecl>(swiftEnum)->getDeclaredInterfaceType(),
-                          false};
-        }
-      }
-    }
-  }
-
+  clang::QualType resultType = desugarIfElaborated(clangDecl->getReturnType());
+  ImportedType importedType = importer::findOptionSetEnum(resultType, *this);
   if (!importedType)
     importedType = importType(resultType, resultKind, addImportDiag,
                               allowNSUIntegerAsIntInResult, Bridgeability::Full,
@@ -3345,7 +3377,8 @@ ImportedType ClangImporter::Implementation::importMethodParamsAndReturnType(
     ImportDiagnosticAdder paramAddDiag(*this, clangDecl, param->getLocation());
 
     auto swiftParamTyOpt = importParameterType(
-        param, optionalityOfParam, allowNSUIntegerAsIntInParam,
+        origDC, clangDecl, param, optionalityOfParam,
+        allowNSUIntegerAsIntInParam,
         kind == SpecialMethodKind::NSDictionarySubscriptGetter, paramIsError,
         paramIsCompletionHandler, completionHandlerErrorParamIndex,
         ArrayRef<GenericTypeParamDecl *>(), paramAddDiag);
@@ -3383,11 +3416,19 @@ ImportedType ClangImporter::Implementation::importMethodParamsAndReturnType(
               decomposeCompletionHandlerType(swiftParamTy, *asyncInfo)) {
         swiftResultTy = replacedSwiftResultTy;
 
+        ImportTypeAttrs attrs;
+        // This is required because a parameter type of a sync variant and
+        // a completion type of an async variant have to match exactly.
+        if (isSendableInferenceOnCompletionHandlerParameterAllowed(origDC,
+                                                                   clangDecl)) {
+          attrs |= ImportTypeAttr::DefaultsToSendable;
+        }
+
         // Import the original completion handler type without adjustments.
         Type origSwiftParamTy =
             importType(paramTy, ImportTypeKind::CompletionHandlerParameter,
                        paramAddDiag, allowNSUIntegerAsIntInParam,
-                       Bridgeability::Full, ImportTypeAttrs(),
+                       Bridgeability::Full, attrs,
                        optionalityOfParam,
                        /*resugarNSErrorPointer=*/!paramIsError, std::nullopt)
                 .getType();
@@ -3478,9 +3519,6 @@ ImportedType ClangImporter::Implementation::importMethodParamsAndReturnType(
           importedType.isImplicitlyUnwrapped()};
 }
 
-ImportedType findOptionSetType(clang::QualType type,
-                               ClangImporter::Implementation &Impl);
-
 ImportedType ClangImporter::Implementation::importAccessorParamsAndReturnType(
     const DeclContext *dc, const clang::ObjCPropertyDecl *property,
     const clang::ObjCMethodDecl *clangDecl, bool isFromSystemModule,
@@ -3506,11 +3544,11 @@ ImportedType ClangImporter::Implementation::importAccessorParamsAndReturnType(
   if (!origDC)
     return {Type(), false};
 
-  auto fieldType = isGetter ? clangDecl->getReturnType()
-                            : clangDecl->getParamDecl(0)->getType();
-
+  auto fieldType =
+      desugarIfElaborated(isGetter ? clangDecl->getReturnType()
+                                   : clangDecl->getParamDecl(0)->getType());
   // Import the property type, independent of what kind of accessor this is.
-  ImportedType importedType = findOptionSetType(fieldType, *this);
+  ImportedType importedType = importer::findOptionSetEnum(fieldType, *this);
   if (!importedType)
     importedType = importPropertyType(property, isFromSystemModule);
   if (!importedType)
diff --git a/lib/ClangImporter/ImporterImpl.h b/lib/ClangImporter/ImporterImpl.h
index 870e68a2152ed..ed4c18dd1ca7a 100644
--- a/lib/ClangImporter/ImporterImpl.h
+++ b/lib/ClangImporter/ImporterImpl.h
@@ -25,6 +25,7 @@
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/ForeignErrorConvention.h"
+#include "swift/AST/Identifier.h"
 #include "swift/AST/LazyResolver.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/RequirementSignature.h"
@@ -202,8 +203,7 @@ enum class ImportTypeAttr : uint8_t {
   Sendable = 1 << 2,
 
   /// Type is in a declaration where it would be imported as Sendable by
-  /// default. This comes directly from the parameters to
-  /// \c getImportTypeAttrs() and merely affects diagnostics.
+  /// default. Currently used for completion handlers.
   DefaultsToSendable = 1 << 3,
 
   /// Import the type of a parameter declared with
@@ -217,6 +217,10 @@ enum class ImportTypeAttr : uint8_t {
   ///
   /// This ensures that the parameter is not marked as Unmanaged.
   CFUnretainedOutParameter = 1 << 5,
+
+  /// Type should be imported as though declaration was marked with
+  /// \c __attribute__((swift_attr("sending"))) .
+  Sending = 1 << 6,
 };
 
 /// Find and iterate over swift attributes embedded in the type
@@ -469,13 +473,17 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   // emitted due to failed SWIFT_SHARED_REFERENCE inference.
   std::unordered_set<const clang::RecordDecl *> DiagnosedCxxRefDecls;
 
+  // Tracks which function templates have already had a diagnostic emitted,
+  // to avoid duplicate diagnostics across instantiations.
+  llvm::DenseSet<std::pair<const clang::FunctionDecl *, DiagID>>
+      DiagnosedTemplateDiagnostics;
+
   const bool ImportForwardDeclarations;
   const bool DisableSwiftBridgeAttr;
   const bool BridgingHeaderExplicitlyRequested;
+  const bool BridgingHeaderIsInternal;
   const bool DisableOverlayModules;
   const bool EnableClangSPI;
-  const bool UseClangIncludeTree;
-  bool importSymbolicCXXDecls;
 
   bool IsReadingBridgingPCH;
   llvm::SmallVector<clang::serialization::SubmoduleID, 2> PCHImportedSubmodules;
@@ -633,22 +641,22 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   /// corresponding to the instantiating Swift compilation's triple. These are
   /// to be used by all IRGen/CodeGen clients of `ClangImporter`.
   std::unique_ptr<clang::TargetInfo> CodeGenTargetInfo;
+  /// - Important: Do not access directly. This field exists only to make sure
+  ///   we own the target options stored in `CodeGenTargetInfo` because
+  ///   `clang::TargetOptions` no longer co-owns them:
+  ///   https://github.com/llvm/llvm-project/pull/106271.
+  std::unique_ptr<clang::TargetOptions> TargetOpts;
   std::unique_ptr<clang::CodeGenOptions> CodeGenOpts;
 
-public:
-  void setSwiftTargetInfo(clang::TargetInfo *SwiftTargetInfo) {
-    CodeGenTargetInfo.reset(SwiftTargetInfo);
-  }
-  clang::TargetInfo *getSwiftTargetInfo() const {
-    return CodeGenTargetInfo.get();
-  }
+  /// Sets the target & code generation options for use by IRGen/CodeGen
+  /// clients of `ClangImporter`. If `CI` is null, the data is drawn from the
+  /// importer's invocation.
+  void configureOptionsForCodeGen(clang::DiagnosticsEngine &Diags,
+                                  clang::CompilerInvocation *CI = nullptr);
 
-  void setSwiftCodeGenOptions(clang::CodeGenOptions *SwiftCodeGenOpts) {
-    CodeGenOpts.reset(SwiftCodeGenOpts);
-  }
-  clang::CodeGenOptions *getSwiftCodeGenOptions() const {
-    return CodeGenOpts.get();
-  }
+  clang::TargetInfo &getCodeGenTargetInfo() const { return *CodeGenTargetInfo; }
+
+  clang::CodeGenOptions &getCodeGenOptions() const;
 
 private:
   /// Generation number that is used for crude versioning.
@@ -677,8 +685,11 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   ///
   /// `.first` corresponds to a getter
   /// `.second` corresponds to a setter
-  llvm::MapVector<std::pair<NominalTypeDecl *, Type>,
-                  std::pair<FuncDecl *, FuncDecl *>> cxxSubscripts;
+  llvm::DenseMap<NominalTypeDecl *,
+                 llvm::MapVector<SmallVector<TypeBase *>,
+                                 std::pair<FuncDecl *, FuncDecl *>,
+                                 std::map<SmallVector<TypeBase *>, unsigned>>>
+      cxxSubscripts;
 
   llvm::MapVector<NominalTypeDecl *, std::pair<FuncDecl *, FuncDecl *>>
       cxxDereferenceOperators;
@@ -690,6 +701,17 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   llvm::DenseMap<std::pair<ValueDecl *, DeclContext *>, ValueDecl *>
       clonedBaseMembers;
 
+  // Map all cloned methods back to the original member
+  llvm::DenseMap<ValueDecl *, ValueDecl *> clonedMembers;
+
+  // Keep track of methods that are unavailale in each class.
+  // We need this set because these methods will be imported lazily. We don't
+  // have the corresponding Swift method when the availability check is
+  // performed, so instead we store the information in this set and then, when
+  // the method is finally generated, we check if it's present here
+  llvm::DenseSet<std::pair<const clang::CXXRecordDecl *, DeclName>>
+      unavailableMethods;
+
 public:
   llvm::DenseMap<const clang::ParmVarDecl*, FuncDecl*> defaultArgGenerators;
 
@@ -698,6 +720,8 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   ValueDecl *importBaseMemberDecl(ValueDecl *decl, DeclContext *newContext,
                                   ClangInheritanceInfo inheritance);
 
+  ValueDecl *getOriginalForClonedMember(const ValueDecl *decl);
+
   static size_t getImportedBaseMemberDeclArity(const ValueDecl *valueDecl);
 
   // Cache for already-specialized function templates and any thunks they may
@@ -709,6 +733,12 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   /// properties.
   llvm::DenseMap<const clang::FunctionDecl *, VarDecl *> FunctionsAsProperties;
 
+  /// Calling AbstractFunctionDecl::getLifetimeDependencies before we added
+  /// the conformances we want to all the imported types is problematic because
+  /// it will populate the conformance too early. To avoid the need for that we
+  /// store functions with interesting lifetimes.
+  llvm::DenseSet<const AbstractFunctionDecl *> returnsSelfDependentValue;
+
   importer::EnumInfo getEnumInfo(const clang::EnumDecl *decl) {
     return getNameImporter().getEnumInfo(decl);
   }
@@ -716,6 +746,18 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
     return getNameImporter().getEnumKind(decl);
   }
 
+  bool findUnavailableMethod(const clang::CXXRecordDecl *classDecl,
+                             DeclName name) {
+    return unavailableMethods.contains({classDecl, name});
+  }
+
+  void insertUnavailableMethod(const clang::CXXRecordDecl *classDecl,
+                               DeclName name) {
+    unavailableMethods.insert({classDecl, name});
+  }
+
+  void handleAmbiguousSwiftName(ValueDecl *decl);
+
 private:
   /// A mapping from imported declarations to their "alternate" declarations,
   /// for cases where a single Clang declaration is imported to two
@@ -812,6 +854,11 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
 public:
   importer::PlatformAvailability platformAvailability;
 
+  /// The synthesized predicate functions for imported `VarDecl`s that represent
+  /// availability domains.
+  llvm::DenseMap<const clang::VarDecl *, FuncDecl *>
+      availabilityDomainPredicates;
+
 private:
   /// For importing names. This is initialized by the ClangImporter::create()
   /// after having set up a suitable Clang instance.
@@ -1058,9 +1105,9 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   StringRef getSwiftNameFromClangName(StringRef name);
 
   /// Retrieve the placeholder source file for use in parsing Swift attributes
-  /// in the given module.
-  SourceFile &getClangSwiftAttrSourceFile(
-      ModuleDecl &module, StringRef attributeText, bool cached);
+  /// of the given Decl.
+  SourceFile &getClangSwiftAttrSourceFile(Decl *MappedDecl,
+                                          StringRef attributeText, bool cached);
 
   /// Create attribute with given text and attach it to decl, creating or
   /// retrieving a chached source file as needed.
@@ -1191,7 +1238,8 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   /// \returns The imported declaration context, or null if it could not
   /// be converted.
   DeclContext *importDeclContextOf(const clang::Decl *D,
-                                   EffectiveClangContext context);
+                                   EffectiveClangContext context,
+                                   bool allowForwardDeclaration = false);
 
   /// Determine whether the given declaration is considered
   /// 'unavailable' in Swift.
@@ -1231,6 +1279,8 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   /// \returns The named module, or null if the module has not been imported.
   ModuleDecl *getNamedModule(StringRef name);
 
+  ImportPath::Builder getSwiftModulePath(const clang::Module *M);
+
   /// Returns the "Foundation" module, if it can be loaded.
   ///
   /// After this has been called, the Foundation module will or won't be loaded
@@ -1460,6 +1510,8 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
 
   /// Import a parameter type
   ///
+  /// \param dc The declaration context in which this parameter appears.
+  /// \param parent The declaration with which this parameter is associated.
   /// \param param The underlaying parameter declaraction.
   /// \param optionalityOfParam The kind of optionality for the parameter
   ///        being imported.
@@ -1487,6 +1539,7 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   ///
   /// \returns The imported parameter result on success, or None on failure.
   std::optional<ImportParameterTypeResult> importParameterType(
+      DeclContext *dc, const clang::Decl *parent,
       const clang::ParmVarDecl *param, OptionalTypeKind optionalityOfParam,
       bool allowNSUIntegerAsInt, bool isNSDictionarySubscriptGetter,
       bool paramIsError, bool paramIsCompletionHandler,
@@ -1685,7 +1738,7 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
     llvm_unreachable("unimplemented for ClangImporter");
   }
 
-  ValueDecl *loadTargetFunctionDecl(const SpecializeAttr *attr,
+  ValueDecl *loadTargetFunctionDecl(const AbstractSpecializeAttr *attr,
                                     uint64_t contextData) override {
     llvm_unreachable("unimplemented for ClangImporter");
   }
@@ -1754,7 +1807,26 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   }
 
   void importSwiftAttrAttributes(Decl *decl);
-  void swiftify(FuncDecl *MappedDecl);
+
+  /// Add the explicit protocol conformance specified by the given swift_attr
+  /// attribute to the given nominal type.
+  void addExplicitProtocolConformance(
+      NominalTypeDecl *decl,
+      clang::SwiftAttrAttr *conformsToAttr,
+      llvm::SmallSet<ProtocolDecl *, 4> &alreadyAdded);
+
+  /// Add explicit protocol conformances from the bases of the given C++ class
+  /// declaration's swift_attr attributes to the given nominal type.
+  void addExplicitProtocolConformancesFromBases(
+      NominalTypeDecl *nominal,
+      const clang::CXXRecordDecl *cxxRecordDecl,
+      bool isBase);
+
+  /// Add implicit typealiases required when turning the given nominal type
+  /// into an option set.
+  void addOptionSetTypealiases(NominalTypeDecl *nominal);
+
+  void swiftify(AbstractFunctionDecl *MappedDecl);
 
   /// Find the lookup table that corresponds to the given Clang module.
   ///
@@ -1902,10 +1974,6 @@ namespace importer {
 bool recordHasReferenceSemantics(const clang::RecordDecl *decl,
                                  ClangImporter::Implementation *importerImpl);
 
-/// Returns true if the given C/C++ reference type uses "immortal"
-/// retain/release functions.
-bool hasImmortalAttrs(const clang::RecordDecl *decl);
-
 /// Whether this is a forward declaration of a type. We ignore forward
 /// declarations in certain cases, and instead process the real declarations.
 bool isForwardDeclOfType(const clang::Decl *decl);
@@ -1917,6 +1985,12 @@ bool shouldSuppressDeclImport(const clang::Decl *decl);
 /// but are now renamed using the swift_name attribute.
 bool isSpecialUIKitStructZeroProperty(const clang::NamedDecl *decl);
 
+/// Identifies certain AppKit constants that have overlay equivalents but are
+/// also annotated with SwiftName API Notes attributes at the same time. Older
+/// Clang versions were silently dropping the API Notes attribute on those
+/// constants.
+bool isSpecialAppKitFunctionKeyProperty(const clang::NamedDecl *decl);
+
 /// \returns true if \p a has the same underlying type as \p b after removing
 /// any pointer/reference specifiers. Note that this does not currently look through
 /// nested types other than pointers or references.
@@ -2028,13 +2102,15 @@ findAnonymousEnumForTypedef(const ASTContext &ctx,
   auto foundDecls = lookupTable->lookup(
       SerializedSwiftName(typedefDecl->getName()), EffectiveClangContext());
 
-  auto found = llvm::find_if(foundDecls, [](SwiftLookupTable::SingleEntry decl) {
-    return decl.is<clang::NamedDecl *>() &&
-        isa<clang::EnumDecl>(decl.get<clang::NamedDecl *>());
-  });
+  auto found =
+      llvm::find_if(foundDecls, [](SwiftLookupTable::SingleEntry decl) {
+        return isa<clang::NamedDecl *>(decl) &&
+               isa<clang::EnumDecl>(cast<clang::NamedDecl *>(decl));
+      });
 
-  if (found != foundDecls.end())
-    return cast<clang::EnumDecl>(found->get<clang::NamedDecl *>());
+  if (found != foundDecls.end()) {
+    return cast<clang::EnumDecl>(cast<clang::NamedDecl *>(*found));
+  }
 
   // If a swift_private attribute has been attached to the enum, its name will
   // be prefixed with two underscores
@@ -2047,14 +2123,15 @@ findAnonymousEnumForTypedef(const ASTContext &ctx,
 
   auto swiftPrivateFound =
       llvm::find_if(foundDecls, [](SwiftLookupTable::SingleEntry decl) {
-        return decl.is<clang::NamedDecl *>() &&
-               isa<clang::EnumDecl>(decl.get<clang::NamedDecl *>()) &&
-               decl.get<clang::NamedDecl *>()
+        return isa<clang::NamedDecl *>(decl) &&
+               isa<clang::EnumDecl>(cast<clang::NamedDecl *>(decl)) &&
+               cast<clang::NamedDecl *>(decl)
                    ->hasAttr<clang::SwiftPrivateAttr>();
       });
 
-  if (swiftPrivateFound != foundDecls.end())
-    return cast<clang::EnumDecl>(swiftPrivateFound->get<clang::NamedDecl *>());
+  if (swiftPrivateFound != foundDecls.end()) {
+    return cast<clang::EnumDecl>(cast<clang::NamedDecl *>(*swiftPrivateFound));
+  }
 
   return std::nullopt;
 }
@@ -2078,11 +2155,56 @@ bool hasUnsafeAPIAttr(const clang::Decl *decl);
 bool hasIteratorAPIAttr(const clang::Decl *decl);
 
 bool hasNonEscapableAttr(const clang::RecordDecl *decl);
-
+bool hasNonCopyableAttr(const clang::RecordDecl *decl);
 bool hasEscapableAttr(const clang::RecordDecl *decl);
 
 bool isViewType(const clang::CXXRecordDecl *decl);
 
+inline const clang::Type *desugarIfElaborated(const clang::Type *type) {
+  if (auto elaborated = dyn_cast<clang::ElaboratedType>(type))
+    return elaborated->desugar().getTypePtr();
+  return type;
+}
+
+inline clang::QualType desugarIfElaborated(clang::QualType type) {
+  if (auto elaborated = dyn_cast<clang::ElaboratedType>(type))
+    return elaborated->desugar();
+  return type;
+}
+
+inline clang::QualType desugarIfBoundsAttributed(clang::QualType type) {
+  if (auto BAT = dyn_cast<clang::BoundsAttributedType>(type))
+    return BAT->desugar();
+  if (auto VT = dyn_cast<clang::ValueTerminatedType>(type))
+    return VT->desugar();
+  if (auto AT = dyn_cast<clang::AttributedType>(type))
+    switch (AT->getAttrKind()) {
+      case clang::attr::PtrUnsafeIndexable:
+      case clang::attr::PtrSingle:
+        return AT->desugar();
+      default:
+        break;
+    }
+  return type;
+}
+
+/// Option set enums are sometimes imported as typedefs which assign a name to
+/// the type, but are unavailable in Swift.
+///
+/// If given such a typedef, this helper function retrieves and imports the
+/// underlying enum type. Returns an empty ImportedType otherwise.
+///
+/// If \a type is an elaborated type, it should be desugared first.
+ImportedType findOptionSetEnum(clang::QualType type,
+                               ClangImporter::Implementation &Impl);
+
+/// Find value declarations in the same module as the given Clang declaration
+/// and with the given name.
+///
+/// The name we're looking for is the Swift name.
+llvm::SmallVector<ValueDecl *, 1>
+getValueDeclsForName(NominalTypeDecl* decl, StringRef name);
+
 } // end namespace importer
 } // end namespace swift
 
diff --git a/lib/ClangImporter/MappedTypes.def b/lib/ClangImporter/MappedTypes.def
index ea4610eb0e215..ca7b63a701250 100644
--- a/lib/ClangImporter/MappedTypes.def
+++ b/lib/ClangImporter/MappedTypes.def
@@ -129,6 +129,9 @@ MAP_STDLIB_TYPE("u_int64_t", UnsignedInt, 64, "UInt64", false, DoNothing)
 MAP_STDLIB_TYPE("va_list", VaList, 0, "CVaListPointer", false, DoNothing)
 MAP_STDLIB_TYPE("__gnuc_va_list", VaList, 0, "CVaListPointer", false, DoNothing)
 MAP_STDLIB_TYPE("__va_list", VaList, 0, "CVaListPointer", false, DoNothing)
+// Cover all va_list family of types just aliased by __builtin_va_list, including
+// __isoc_va_list from wasi-libc.
+MAP_STDLIB_TYPE("__builtin_va_list", VaList, 0, "CVaListPointer", false, DoNothing)
 
 // libkern/OSTypes.h types.
 MAP_STDLIB_TYPE("UInt", UnsignedInt, 32, "CUnsignedInt", false, DoNothing)
diff --git a/lib/ClangImporter/Serializability.cpp b/lib/ClangImporter/Serializability.cpp
index b57c47dce21c9..4802ea506f3d3 100644
--- a/lib/ClangImporter/Serializability.cpp
+++ b/lib/ClangImporter/Serializability.cpp
@@ -330,6 +330,9 @@ namespace {
     void writeTypeCoupledDeclRefInfo(clang::TypeCoupledDeclRefInfo info) {
       llvm_unreachable("TypeCoupledDeclRefInfo shouldn't be reached from swift");
     }
+    void writeHLSLSpirvOperand(clang::SpirvOperand) {
+      llvm_unreachable("SpirvOperand shouldn't be reached from swift");
+    }
   };
 }
 
diff --git a/lib/ClangImporter/SwiftBridging/swift/bridging b/lib/ClangImporter/SwiftBridging/swift/bridging
index c111d82ad884d..d1083b19eb50d 100644
--- a/lib/ClangImporter/SwiftBridging/swift/bridging
+++ b/lib/ClangImporter/SwiftBridging/swift/bridging
@@ -1,5 +1,5 @@
-// -*- C++ -*-
-//===------------------ bridging - C++ and Swift Interop --------*- C++ -*-===//
+// -*- C -*-
+//===------------------ bridging - C and Swift Interop ----------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -32,7 +32,7 @@
 /// that return a `class` or `struct` type that is annotated with this macro.
 #define SWIFT_SELF_CONTAINED __attribute__((swift_attr("import_owned")))
 
-/// Specifies that a C++ method returns a value that is presumed to contain
+/// Specifies that a method returns a value that is presumed to contain
 /// objects whose lifetime is not dependent on `this` or other parameters passed
 /// to the method.
 #define SWIFT_RETURNS_INDEPENDENT_VALUE __attribute__((swift_attr("import_unsafe")))
@@ -45,16 +45,16 @@
 #define _CXX_INTEROP_CONCAT(...) \
   _CXX_INTEROP_CONCAT_(__VA_ARGS__,,,,,,,,,,,,,,,,,)
 
-/// Specifies that a C++ `class` or `struct` is reference-counted using
+/// Specifies that a `class` or `struct` is reference-counted using
 /// the given `retain` and `release` functions. This annotation lets Swift import
 /// such a type as reference counted type in Swift, taking advantage of Swift's
 /// automatic reference counting.
 ///
 /// This example shows how to use this macro to let Swift know that
-/// a non-copyable reference counted C++ class can be imported as a reference counted type in Swift:
+/// a reference counted C++ class can be imported as a reference counted type in Swift:
 ///  ```c++
 ///    class SWIFT_SHARED_REFERENCE(retainSharedObject, releaseSharedObject)
-///    SharedObject : NonCopyable, IntrusiveReferenceCounted<SharedObject> {
+///    SharedObject : IntrusiveReferenceCounted<SharedObject> {
 ///    public:
 ///      static SharedObject* create();
 ///      void doSomething();
@@ -71,21 +71,20 @@
 ///    object.doSomething()
 ///    // The Swift compiler will release object here.
 ///  ```
-#define SWIFT_SHARED_REFERENCE(_retain, _release)                                \
+#define SWIFT_SHARED_REFERENCE(_retain, _release)                          \
   __attribute__((swift_attr("import_reference")))                          \
   __attribute__((swift_attr(_CXX_INTEROP_STRINGIFY(retain:_retain))))      \
   __attribute__((swift_attr(_CXX_INTEROP_STRINGIFY(release:_release))))
 
-/// Specifies that a C++ `class` or `struct` is a reference type whose lifetime
+/// Specifies that a `class` or `struct` is a reference type whose lifetime
 /// is presumed to be immortal, i.e. the reference to such object is presumed to
 /// always be valid. This annotation lets Swift import such a type as a reference
 /// type in Swift.
 ////
 /// This example shows how to use this macro to let Swift know that
-/// a non-copyable singleton C++ class can be imported as a reference type in Swift:
+/// a singleton C++ class can be imported as a reference type in Swift:
 ///  ```c++
-///    class SWIFT_IMMORTAL_REFERENCE
-///    LoggerSingleton : NonCopyable {
+///    class SWIFT_IMMORTAL_REFERENCE LoggerSingleton {
 ///    public:
 ///      static LoggerSingleton &getInstance();
 ///      void log(int x);
@@ -98,24 +97,24 @@
 ///    let logger = LoggerSingleton.getInstance()
 ///    logger.log(123)
 ///  ```
-#define SWIFT_IMMORTAL_REFERENCE                                                \
-  __attribute__((swift_attr("import_reference")))                         \
-  __attribute__((swift_attr(_CXX_INTEROP_STRINGIFY(retain:immortal))))    \
-  __attribute__((swift_attr(_CXX_INTEROP_STRINGIFY(release:immortal))))
+#define SWIFT_IMMORTAL_REFERENCE                     \
+  __attribute__((swift_attr("import_reference")))    \
+  __attribute__((swift_attr("retain:immortal")))     \
+  __attribute__((swift_attr("release:immortal")))
 
-/// Specifies that a C++ `class` or `struct` is a reference type whose lifetime
+/// Specifies that a `class` or `struct` is a reference type whose lifetime
 /// is not managed automatically. The programmer must validate that any reference
 /// to such object is valid themselves. This annotation lets Swift import such a type as a reference type in Swift.
-#define SWIFT_UNSAFE_REFERENCE                                                  \
-  __attribute__((swift_attr("import_reference")))                         \
-  __attribute__((swift_attr(_CXX_INTEROP_STRINGIFY(retain:immortal))))    \
-  __attribute__((swift_attr(_CXX_INTEROP_STRINGIFY(release:immortal))))   \
+#define SWIFT_UNSAFE_REFERENCE                       \
+  __attribute__((swift_attr("import_reference")))    \
+  __attribute__((swift_attr("retain:immortal")))     \
+  __attribute__((swift_attr("release:immortal")))    \
   __attribute__((swift_attr("unsafe")))
 
 /// Specifies a name that will be used in Swift for this declaration instead of its original name.
 #define SWIFT_NAME(_name) __attribute__((swift_name(#_name)))
 
-/// Specifies that a specific C++ `class` or `struct` conforms to a
+/// Specifies that a specific `class` or `struct` conforms to a
 /// a specific Swift protocol.
 ///
 /// This example shows how to use this macro to conform a class template to a Swift protocol:
@@ -147,7 +146,7 @@
 #define SWIFT_MUTATING \
   __attribute__((swift_attr("mutating")))
 
-/// Specifies that a specific c++ type such class or struct should be imported as type marked 
+/// Specifies that a specific class or struct should be imported as type marked
 /// as `@unchecked Sendable` type in swift. If this annotation is used, the type is therefore allowed to
 /// use safely across async contexts.
 ///
@@ -160,19 +159,48 @@
 #define SWIFT_UNCHECKED_SENDABLE \
   __attribute__((swift_attr("@Sendable")))
 
-/// Specifies that a specific c++ type such class or struct should be imported
-/// as a non-copyable Swift value type.
+/// Specifies that a `class` or `struct` should be imported as a non-copyable
+/// Swift value type.
 #define SWIFT_NONCOPYABLE \
   __attribute__((swift_attr("~Copyable")))
 
-/// Specifies that a specific c++ type such class or struct should be imported
-/// as a non-escapable Swift value type when the non-escapable language feature
-/// is enabled.
+/// Specifies that a `class` or `struct` should be imported as a non-copyable
+/// Swift value type that calls the given `_destroy` function when a value is no
+/// longer used.
+///
+/// This example shows how to use this macro to let Swift know that
+/// a given C struct should have its members freed when it goes out of scope:
+///  ```c
+///    typedef struct SWIFT_NONCOPYABLE_WITH_DESTROY(mytypeFreeMembers) MyType {
+///      void *storage
+///    } MyType;
+///
+///    void mytypeFreeMembers(MyType toBeDestroyed);
+///    MyType mytypeCreate(void);
+///  ```
+///
+///  Usage in Swift:
+///   ```swift
+///   let mt = mytypeCreate()
+///   let mt2 = mt   // consumes mt
+///   // once mt2 is unused, Swift will call mytypeFreeMembers(mt2)
+///   ```
+#define SWIFT_NONCOPYABLE_WITH_DESTROY(_destroy) \
+  __attribute__((swift_attr("~Copyable"))) \
+  __attribute__((swift_attr(_CXX_INTEROP_STRINGIFY(destroy:_destroy))))
+
+/// Specifies that a C++ `class` or `struct` should be imported as a copyable
+/// Swift value if all of the specified template arguments are copyable.
+#define SWIFT_COPYABLE_IF(...) \
+  __attribute__((swift_attr("copyable_if:" _CXX_INTEROP_CONCAT(__VA_ARGS__))))
+
+/// Specifies that a specific class or struct should be imported
+/// as a non-escapable Swift value type.
 #define SWIFT_NONESCAPABLE \
   __attribute__((swift_attr("~Escapable")))
 
-/// Specifies that a specific c++ type such class or struct should be imported
-/// as a escapable Swift value. While this matches the default behavior,
+/// Specifies that a specific class or struct should be imported
+/// as an escapable Swift value. While this matches the default behavior,
 /// in safe mode interop mode it ensures that the type is not marked as
 /// unsafe.
 #define SWIFT_ESCAPABLE \
@@ -183,14 +211,31 @@
 #define SWIFT_ESCAPABLE_IF(...) \
   __attribute__((swift_attr("escapable_if:" _CXX_INTEROP_CONCAT(__VA_ARGS__))))
 
-/// Specifies that the return value is passed as owned for C++ functions and
+/// Specifies that the return value is passed as owned for functions and
 /// methods returning types annotated as `SWIFT_SHARED_REFERENCE`
 #define SWIFT_RETURNS_RETAINED __attribute__((swift_attr("returns_retained")))
-/// Specifies that the return value is passed as unowned for C++ functions and
+/// Specifies that the return value is passed as unowned for functions and
 /// methods returning types annotated as `SWIFT_SHARED_REFERENCE`
 #define SWIFT_RETURNS_UNRETAINED                                               \
   __attribute__((swift_attr("returns_unretained")))
 
+/// Applied to a foreign reference type annotated with
+/// SWIFT_SHARED_REFERENCE. Indicates that APIs returning this type are
+/// assumed to return an unowned (+0) value by default, unless explicitly annotated
+/// with SWIFT_RETURNS_RETAINED.
+///
+/// For example:
+/// ```c++
+/// struct SWIFT_SHARED_REFERENCE(retainBar, releaseBar)
+/// SWIFT_RETURNED_AS_UNRETAINED_BY_DEFAULT
+/// Bar { ... };
+/// ```
+///
+/// In Swift, APIs returning `Bar*` will be assumed to return an unowned
+/// value.
+#define SWIFT_RETURNED_AS_UNRETAINED_BY_DEFAULT                                    \
+  __attribute__((swift_attr("returned_as_unretained_by_default")))
+
 /// Specifies that the non-public members of a C++ class, struct, or union can
 /// be accessed from extensions of that type, in the given file ID.
 ///
@@ -241,6 +286,8 @@
 #define SWIFT_MUTATING 
 #define SWIFT_UNCHECKED_SENDABLE
 #define SWIFT_NONCOPYABLE
+#define SWIDT_NONCOPYABLE_WITH_DESTROY(_destroy)
+#define SWIFT_COPYABLE_IF(...)
 #define SWIFT_NONESCAPABLE
 #define SWIFT_ESCAPABLE
 #define SWIFT_ESCAPABLE_IF(...)
diff --git a/lib/ClangImporter/SwiftDeclSynthesizer.cpp b/lib/ClangImporter/SwiftDeclSynthesizer.cpp
index c3803657b6795..751a1e6d202a2 100644
--- a/lib/ClangImporter/SwiftDeclSynthesizer.cpp
+++ b/lib/ClangImporter/SwiftDeclSynthesizer.cpp
@@ -11,16 +11,20 @@
 //===----------------------------------------------------------------------===//
 
 #include "SwiftDeclSynthesizer.h"
+#include "CXXMethodBridging.h"
 #include "swift/AST/ASTMangler.h"
+#include "swift/AST/Attr.h"
 #include "swift/AST/AttrKind.h"
 #include "swift/AST/Builtins.h"
 #include "swift/AST/Decl.h"
+#include "swift/AST/DiagnosticsClangImporter.h"
 #include "swift/AST/Expr.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/Pattern.h"
 #include "swift/AST/Stmt.h"
+#include "swift/AST/TypeCheckRequests.h"
 #include "swift/Basic/Assertions.h"
-#include "swift/ClangImporter/CXXMethodBridging.h"
+#include "swift/ClangImporter/ClangImporterRequests.h"
 #include "clang/AST/Mangle.h"
 #include "clang/Sema/DelayedDiagnostic.h"
 
@@ -44,7 +48,7 @@ static Argument createSelfArg(AccessorDecl *accessorDecl) {
 
 static CallExpr *createAccessorImplCallExpr(FuncDecl *accessorImpl,
                                             Argument selfArg,
-                                            DeclRefExpr *keyRefExpr = nullptr) {
+                                            ArrayRef<Expr *> keyRefExprs) {
   ASTContext &ctx = accessorImpl->getASTContext();
 
   auto accessorImplExpr =
@@ -57,12 +61,8 @@ static CallExpr *createAccessorImplCallExpr(FuncDecl *accessorImpl,
   accessorImplDotCallExpr->setType(accessorImpl->getMethodInterfaceType());
   accessorImplDotCallExpr->setThrows(nullptr);
 
-  ArgumentList *argList;
-  if (keyRefExpr) {
-    argList = ArgumentList::forImplicitUnlabeled(ctx, {keyRefExpr});
-  } else {
-    argList = ArgumentList::forImplicitUnlabeled(ctx, {});
-  }
+  ArgumentList *argList = ArgumentList::forImplicitUnlabeled(ctx, keyRefExprs);
+
   auto *accessorImplCallExpr =
       CallExpr::createImplicit(ctx, accessorImplDotCallExpr, argList);
   accessorImplCallExpr->setType(accessorImpl->getResultInterfaceType());
@@ -131,7 +131,7 @@ static AccessorDecl *makeFieldSetterDecl(ClangImporter::Implementation &Impl,
   setterDecl->setIsDynamic(false);
   if (!isa<ClassDecl>(importedDecl))
     setterDecl->setSelfAccessKind(SelfAccessKind::Mutating);
-  setterDecl->setAccess(importedFieldDecl->getFormalAccess());
+  setterDecl->setAccess(importedFieldDecl->getSetterFormalAccess());
 
   return setterDecl;
 }
@@ -195,6 +195,40 @@ Type SwiftDeclSynthesizer::getConstantLiteralType(
   }
 }
 
+// This method is exposed on SwiftDeclSynthesizer to keep code that accesses
+// RawTypes together.
+bool SwiftDeclSynthesizer::isCGFloat(Type type) {
+  auto found = ImporterImpl.RawTypes.find(type->getAnyNominal());
+  if (found == ImporterImpl.RawTypes.end()) {
+    return false;
+  }
+  
+  Type importTy = found->second;
+  return importTy->isCGFloat();
+}
+
+// This method is exposed on SwiftDeclSynthesizer to keep code that accesses
+// RawTypes together.
+bool SwiftDeclSynthesizer::isObjCBool(Type type) {
+  auto found = ImporterImpl.RawTypes.find(type->getAnyNominal());
+  if (found == ImporterImpl.RawTypes.end()) {
+    return false;
+  }
+  
+  Type importTy = found->second;
+  return importTy->isObjCBool();
+}
+
+bool SwiftDeclSynthesizer::isUnicodeScalar(Type type) {
+  auto found = ImporterImpl.RawTypes.find(type->getAnyNominal());
+  if (found == ImporterImpl.RawTypes.end()) {
+    return false;
+  }
+
+  Type importTy = found->second;
+  return importTy->isUnicodeScalar();
+}
+
 ValueDecl *SwiftDeclSynthesizer::createConstant(Identifier name,
                                                 DeclContext *dc, Type type,
                                                 const clang::APValue &value,
@@ -426,7 +460,6 @@ ValueDecl *SwiftDeclSynthesizer::createConstant(Identifier name,
       /*ThrowsLoc=*/SourceLoc(), /*ThrownType=*/TypeLoc(),
       params, type, dc);
   func->setStatic(isStatic);
-  func->setAccess(getOverridableAccessLevel(dc));
   func->setIsObjC(false);
   func->setIsDynamic(false);
 
@@ -436,9 +469,7 @@ ValueDecl *SwiftDeclSynthesizer::createConstant(Identifier name,
 
   // Mark the function transparent so that we inline it away completely.
   func->getAttrs().add(new (C) TransparentAttr(/*implicit*/ true));
-  auto nonisolatedAttr =
-      new (C) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true);
-  var->getAttrs().add(nonisolatedAttr);
+  var->getAttrs().add(NonisolatedAttr::createImplicit(C));
 
   // Set the function up as the getter.
   ImporterImpl.makeComputed(var, func, nullptr);
@@ -1546,33 +1577,36 @@ synthesizeUnwrappingGetterOrAddressGetterBody(AbstractFunctionDecl *afd,
   ASTContext &ctx = getterDecl->getASTContext();
 
   auto selfArg = createSelfArg(getterDecl);
-  DeclRefExpr *keyRefExpr = getterDecl->getParameters()->size() == 0
-                                ? nullptr
-                                : createParamRefExpr(getterDecl, 0);
+  SmallVector<Expr *> arguments;
+  for (size_t idx = 0, end = getterDecl->getParameters()->size(); idx < end;
+       ++idx)
+    arguments.push_back(createParamRefExpr(getterDecl, idx));
 
   Type elementTy = getterDecl->getResultInterfaceType();
 
   auto *getterImplCallExpr =
-      createAccessorImplCallExpr(getterImpl, selfArg, keyRefExpr);
+      createAccessorImplCallExpr(getterImpl, selfArg, arguments);
 
   // This default handles C++'s operator[] that returns a value type.
   Expr *propertyExpr = getterImplCallExpr;
   PointerTypeKind ptrKind;
 
-  // The following check returns true if the subscript operator returns a C++
-  // reference type. This check actually checks to see if the type is a pointer
-  // type, but this does not apply to C pointers because they are Optional types
-  // when imported. TODO: Use a more obvious check here.
+  // The following check returns true if the subscript operator returns a
+  // C++ reference type. This check actually checks to see if the type is
+  // a pointer type, but this does not apply to C pointers because they
+  // are Optional types when imported. TODO: Use a more obvious check
+  // here.
   if (!isAddress &&
       getterImpl->getResultInterfaceType()->getAnyPointerElementType(ptrKind)) {
-    // `getterImpl` can return either UnsafePointer or UnsafeMutablePointer.
-    // Retrieve the corresponding `.pointee` declaration.
+    // `getterImpl` can return either UnsafePointer or
+    // UnsafeMutablePointer. Retrieve the corresponding `.pointee`
+    // declaration.
     VarDecl *pointeePropertyDecl = ctx.getPointerPointeePropertyDecl(ptrKind);
 
     // Handle operator[] that returns a reference type.
-    SubstitutionMap subMap = SubstitutionMap::get(
-        ctx.getUnsafePointerDecl()->getGenericSignature(), {elementTy},
-        LookUpConformanceInModule());
+    SubstitutionMap subMap =
+        SubstitutionMap::get(ctx.getUnsafePointerDecl()->getGenericSignature(),
+                             {elementTy}, LookUpConformanceInModule());
     auto pointeePropertyRefExpr = new (ctx) MemberRefExpr(
         getterImplCallExpr, SourceLoc(),
         ConcreteDeclRef(pointeePropertyDecl, subMap), DeclNameLoc(),
@@ -1617,16 +1651,15 @@ synthesizeUnwrappingSetterBody(AbstractFunctionDecl *afd, void *context) {
 
   auto selfArg = createSelfArg(setterDecl);
   DeclRefExpr *valueParamRefExpr = createParamRefExpr(setterDecl, 0);
-  // For a subscript this decl will have two parameters, for a pointee property
-  // it will only have one.
-  DeclRefExpr *keyParamRefExpr = setterDecl->getParameters()->size() == 1
-                                     ? nullptr
-                                     : createParamRefExpr(setterDecl, 1);
+  SmallVector<Expr *> arguments;
+  for (size_t idx = 1, end = setterDecl->getParameters()->size(); idx < end;
+       ++idx)
+    arguments.push_back(createParamRefExpr(setterDecl, idx));
 
   Type elementTy = valueParamRefExpr->getDecl()->getInterfaceType();
 
   auto *setterImplCallExpr =
-      createAccessorImplCallExpr(setterImpl, selfArg, keyParamRefExpr);
+      createAccessorImplCallExpr(setterImpl, selfArg, arguments);
 
   VarDecl *pointeePropertyDecl =
       ctx.getPointerPointeePropertyDecl(PTK_UnsafeMutablePointer);
@@ -1663,7 +1696,7 @@ synthesizeUnwrappingAddressSetterBody(AbstractFunctionDecl *afd,
 
   auto selfArg = createSelfArg(setterDecl);
   auto *setterImplCallExpr =
-      createAccessorImplCallExpr(setterImpl, selfArg, nullptr);
+      createAccessorImplCallExpr(setterImpl, selfArg, {});
 
   auto *returnStmt = ReturnStmt::createImplicit(ctx, setterImplCallExpr);
 
@@ -1682,6 +1715,7 @@ SubscriptDecl *SwiftDeclSynthesizer::makeSubscript(FuncDecl *getter,
   FuncDecl *getterImpl = getter ? getter : setter;
   FuncDecl *setterImpl = setter;
 
+  // FIXME: support unsafeAddress accessors.
   // Get the return type wrapped in `Unsafe(Mutable)Pointer<T>`.
   const auto rawElementTy = getterImpl->getResultInterfaceType();
   // Unwrap `T`. Use rawElementTy for return by value.
@@ -1691,15 +1725,16 @@ SubscriptDecl *SwiftDeclSynthesizer::makeSubscript(FuncDecl *getter,
 
   auto &ctx = ImporterImpl.SwiftContext;
 
-  assert(getterImpl->getParameters()->size() == 1 &&
-         "subscript can only have 1 parameter");
-  auto bodyParam = ParamDecl::clone(ctx, getterImpl->getParameters()->get(0));
-  // If the subscript parameter is unnamed, give it a name to make sure SILGen
-  // creates a variable for it.
-  if (bodyParam->getName().empty())
-    bodyParam->setName(ctx.getIdentifier("__index"));
-
-  auto bodyParams = ParameterList::create(ctx, bodyParam);
+  SmallVector<ParamDecl *> paramVec;
+  for (auto [i, param] : llvm::enumerate(*getterImpl->getParameters())) {
+    auto clonedParam = ParamDecl::clone(ctx, param);
+    // If the subscript parameter is unnamed, give it a name to make sure SILGen
+    // creates a variable for it.
+    if (clonedParam->getName().empty())
+      clonedParam->setName(ctx.getIdentifier("__index" + std::to_string(i)));
+    paramVec.push_back(clonedParam);
+  }
+  auto bodyParams = ParameterList::create(ctx, paramVec);
   DeclName name(ctx, DeclBaseName::createSubscript(), bodyParams);
   auto dc = getterImpl->getDeclContext();
 
@@ -1734,8 +1769,11 @@ SubscriptDecl *SwiftDeclSynthesizer::makeSubscript(FuncDecl *getter,
     paramVarDecl->setSpecifier(ParamSpecifier::Default);
     paramVarDecl->setInterfaceType(elementTy);
 
-    auto setterParamList =
-        ParameterList::create(ctx, {paramVarDecl, bodyParams->get(0)});
+    SmallVector<ParamDecl *> setterParams;
+    setterParams.push_back(paramVarDecl);
+    setterParams.append(bodyParams->begin(), bodyParams->end());
+
+    auto setterParamList = ParameterList::create(ctx, setterParams);
 
     setterDecl = AccessorDecl::create(
         ctx, setterImpl->getLoc(), setterImpl->getLoc(), AccessorKind::Set,
@@ -1775,6 +1813,8 @@ SwiftDeclSynthesizer::makeDereferencedPointeeProperty(FuncDecl *getter,
   FuncDecl *getterImpl = getter ? getter : setter;
   FuncDecl *setterImpl = setter;
   auto dc = getterImpl->getDeclContext();
+  bool resultDependsOnSelf =
+      ImporterImpl.returnsSelfDependentValue.contains(getterImpl);
 
   // Get the return type wrapped in `Unsafe(Mutable)Pointer<T>`.
   const auto rawElementTy = getterImpl->getResultInterfaceType();
@@ -1785,9 +1825,9 @@ SwiftDeclSynthesizer::makeDereferencedPointeeProperty(FuncDecl *getter,
   // Use 'address' or 'mutableAddress' accessors for non-copyable
   // types that are returned indirectly.
   bool isNoncopyable = dc->mapTypeIntoContext(elementTy)->isNoncopyable();
-  bool isImplicit = !isNoncopyable;
+  bool isImplicit = !(isNoncopyable || resultDependsOnSelf);
   bool useAddress =
-      rawElementTy->getAnyPointerElementType() && isNoncopyable;
+      rawElementTy->getAnyPointerElementType() && (isNoncopyable || resultDependsOnSelf);
 
   auto result = new (ctx)
       VarDecl(/*isStatic*/ false, VarDecl::Introducer::Var,
@@ -1908,7 +1948,7 @@ synthesizeSuccessorFuncBody(AbstractFunctionDecl *afd, void *context) {
 
   // Call `operator++`.
   auto incrementExpr = createAccessorImplCallExpr(
-      incrementImpl, Argument::implicitInOut(ctx, copyRefLValueExpr));
+      incrementImpl, Argument::implicitInOut(ctx, copyRefLValueExpr), {});
 
   auto copyRefRValueExpr = new (ctx) DeclRefExpr(copyDecl, DeclNameLoc(),
                                                  /*implicit*/ true);
@@ -2023,11 +2063,6 @@ clang::CXXMethodDecl *SwiftDeclSynthesizer::synthesizeCXXForwardingMethod(
   assert(!method->isStatic() ||
          method->getNameInfo().getName().getCXXOverloadedOperator() ==
              clang::OO_Call);
-  // When emitting symbolic decls, the method might not have a concrete
-  // record type as this type.
-  if (ImporterImpl.importSymbolicCXXDecls && !method->isStatic() &&
-      !method->getThisType()->getPointeeCXXRecordDecl())
-    return nullptr;
 
   // Create a new method in the derived class that calls the base method.
   clang::DeclarationName name = method->getNameInfo().getName();
@@ -2113,6 +2148,8 @@ clang::CXXMethodDecl *SwiftDeclSynthesizer::synthesizeCXXForwardingMethod(
     // convention.
     newMethod->addAttr(clang::CFReturnsRetainedAttr::CreateImplicit(clangCtx));
   }
+  if (auto swiftNameAttr = method->getAttr<clang::SwiftNameAttr>())
+    newMethod->addAttr(swiftNameAttr->clone(clangCtx));
 
   llvm::SmallVector<clang::ParmVarDecl *, 4> params;
   for (size_t i = 0; i < method->getNumParams(); ++i) {
@@ -2169,11 +2206,18 @@ clang::CXXMethodDecl *SwiftDeclSynthesizer::synthesizeCXXForwardingMethod(
   for (size_t i = 0; i < newMethod->getNumParams(); ++i) {
     auto *param = newMethod->getParamDecl(i);
     auto type = param->getType();
-    if (type->isReferenceType())
-      type = type->getPointeeType();
-    args.push_back(new (clangCtx) clang::DeclRefExpr(
-        clangCtx, param, false, type, clang::ExprValueKind::VK_LValue,
-        clang::SourceLocation()));
+    clang::Expr *argExpr = new (clangCtx) clang::DeclRefExpr(
+        clangCtx, param, false, type.getNonReferenceType(),
+        clang::ExprValueKind::VK_LValue, clang::SourceLocation());
+    if (type->isRValueReferenceType()) {
+      argExpr = clangSema
+                    .BuildCXXNamedCast(
+                        clang::SourceLocation(), clang::tok::kw_static_cast,
+                        clangCtx.getTrivialTypeSourceInfo(type), argExpr,
+                        clang::SourceRange(), clang::SourceRange())
+                    .get();
+    }
+    args.push_back(argExpr);
   }
   auto memberCall = clangSema.BuildCallExpr(
       nullptr, memberExpr, clang::SourceLocation(), args,
@@ -2269,7 +2313,7 @@ SwiftDeclSynthesizer::makeOperator(FuncDecl *operatorMethod,
 // MARK: C++ virtual methods
 
 FuncDecl *SwiftDeclSynthesizer::makeVirtualMethod(
-    const clang::CXXMethodDecl *clangMethodDecl) {
+    const clang::CXXMethodDecl *clangMethodDecl, StringRef swiftName) {
   auto clangDC = clangMethodDecl->getParent();
   auto &ctx = ImporterImpl.SwiftContext;
 
@@ -2280,6 +2324,25 @@ FuncDecl *SwiftDeclSynthesizer::makeVirtualMethod(
       clangDC, clangDC, clangMethodDecl, ForwardingMethodKind::Virtual,
       ReferenceReturnTypeBehaviorForBaseMethodSynthesis::KeepReference,
       /*forceConstQualifier*/ false);
+  
+  // If the override has a swift_name different from the base
+  // method, we ignore the swift_name attribute and instead use the base method's name.
+  // In this case, swiftName holds the correct derived method name obtained through NameImporter
+  if (clangMethodDecl->size_overridden_methods() > 0) {
+    if (auto oldSwiftNameAttr = newMethod->getAttr<clang::SwiftNameAttr>()) {
+      auto oldSwiftName = oldSwiftNameAttr->getName();
+      
+      if (swiftName != oldSwiftName) {
+        ImporterImpl.diagnose(HeaderLoc(oldSwiftNameAttr->getLoc()),
+                              diag::swift_name_attr_ignored,
+                              oldSwiftName);
+        oldSwiftNameAttr->setName(newMethod->getASTContext(), swiftName);
+      }
+    } else {
+      newMethod->addAttr(clang::SwiftNameAttr::CreateImplicit(
+          newMethod->getASTContext(), swiftName));
+    }
+  }
 
   auto result = dyn_cast_or_null<FuncDecl>(
       ctx.getClangModuleLoader()->importDeclDirectly(newMethod));
@@ -2317,7 +2380,7 @@ synthesizeComputedGetterFromCXXMethod(AbstractFunctionDecl *afd,
 
   auto selfArg = createSelfArg(accessor);
 
-  auto *getterImplCallExpr = createAccessorImplCallExpr(method, selfArg);
+  auto *getterImplCallExpr = createAccessorImplCallExpr(method, selfArg, {});
   auto &ctx = method->getASTContext();
   auto *returnStmt = ReturnStmt::createImplicit(ctx, getterImplCallExpr);
   auto *body = BraceStmt::create(ctx, SourceLoc(), {returnStmt}, SourceLoc());
@@ -2335,7 +2398,7 @@ synthesizeComputedSetterFromCXXMethod(AbstractFunctionDecl *afd,
   DeclRefExpr *valueParamRefExpr = createParamRefExpr(setterDecl, 0);
 
   auto *getterImplCallExpr =
-      createAccessorImplCallExpr(setterImpl, selfArg, valueParamRefExpr);
+      createAccessorImplCallExpr(setterImpl, selfArg, {valueParamRefExpr});
 
   auto body = BraceStmt::create(setterImpl->getASTContext(), SourceLoc(),
                                 {getterImplCallExpr}, SourceLoc());
@@ -2516,6 +2579,13 @@ SwiftDeclSynthesizer::makeDefaultArgument(const clang::ParmVarDecl *param,
       ImporterImpl.ImportedHeaderUnit);
   funcDecl->setBodySynthesizer(synthesizeDefaultArgumentBody, (void *)param);
   funcDecl->setAccess(AccessLevel::Public);
+  funcDecl->getAttrs().add(new (ctx)
+                               AlwaysEmitIntoClientAttr(/*IsImplicit=*/true));
+  // At this point, the parameter/return types of funcDecl might not be imported
+  // into Swift completely, meaning that their protocol conformances might not
+  // be populated yet. Prevent LifetimeDependenceInfoRequest from prematurely
+  // populating the conformance table for the types involved.
+  ctx.evaluator.cacheOutput(LifetimeDependenceInfoRequest{funcDecl}, {});
 
   ImporterImpl.defaultArgGenerators[param] = funcDecl;
 
@@ -2534,128 +2604,538 @@ SwiftDeclSynthesizer::makeDefaultArgument(const clang::ParmVarDecl *param,
 
 // MARK: C++ foreign reference type constructors
 
-clang::CXXMethodDecl *
+llvm::SmallVector<clang::CXXMethodDecl *, 4>
 SwiftDeclSynthesizer::synthesizeStaticFactoryForCXXForeignRef(
     const clang::CXXRecordDecl *cxxRecordDecl) {
 
+  if (!cxxRecordDecl->isCompleteDefinition() || cxxRecordDecl->isAbstract())
+    return {};
+
   clang::ASTContext &clangCtx = cxxRecordDecl->getASTContext();
   clang::Sema &clangSema = ImporterImpl.getClangSema();
 
   clang::QualType cxxRecordTy = clangCtx.getRecordType(cxxRecordDecl);
+  clang::SourceLocation cxxRecordDeclLoc = cxxRecordDecl->getLocation();
 
-  clang::CXXConstructorDecl *defaultCtorDecl = nullptr;
-  for (clang::CXXConstructorDecl *ctor : cxxRecordDecl->ctors()) {
-    if (ctor->parameters().empty() && !ctor->isDeleted() &&
-        ctor->getAccess() != clang::AS_private &&
-        ctor->getAccess() != clang::AS_protected) {
-      defaultCtorDecl = ctor;
-      break;
-    }
+  llvm::SmallVector<clang::CXXConstructorDecl *, 4> ctorDeclsForSynth;
+  for (clang::CXXConstructorDecl *ctorDecl : cxxRecordDecl->ctors()) {
+    if (ctorDecl->isDeleted() || ctorDecl->getAccess() == clang::AS_private ||
+        ctorDecl->getAccess() == clang::AS_protected ||
+        ctorDecl->isCopyOrMoveConstructor() || ctorDecl->isVariadic())
+      continue;
+
+    bool hasDefaultArg = !ctorDecl->parameters().empty() &&
+                         ctorDecl->parameters().back()->hasDefaultArg();
+    // TODO: Add support for default args in ctors for C++ foreign reference
+    // types.
+    if (hasDefaultArg)
+      continue;
+    ctorDeclsForSynth.push_back(ctorDecl);
   }
-  if (!defaultCtorDecl)
-    return nullptr;
+
+  if (ctorDeclsForSynth.empty())
+    return {};
 
   clang::FunctionDecl *operatorNew = nullptr;
   clang::FunctionDecl *operatorDelete = nullptr;
-  bool passAlignment = false;
+  clang::ImplicitAllocationParameters IAP(clang::AlignedAllocationMode::No);
+  clang::Sema::SFINAETrap trap(clangSema);
   bool findingAllocFuncFailed = clangSema.FindAllocationFunctions(
-      cxxRecordDecl->getLocation(), clang::SourceRange(), clang::Sema::AFS_Both,
-      clang::Sema::AFS_Both, cxxRecordTy,
-      /*IsArray*/ false, passAlignment, clang::MultiExprArg(), operatorNew,
-      operatorDelete, /*Diagnose*/ false);
-  if (findingAllocFuncFailed || !operatorNew || operatorNew->isDeleted() ||
+      cxxRecordDeclLoc, clang::SourceRange(),
+      clang::AllocationFunctionScope::Both,
+      clang::AllocationFunctionScope::Both, cxxRecordTy, /*IsArray=*/false, IAP,
+      clang::MultiExprArg(), operatorNew, operatorDelete,
+      /*Diagnose=*/false);
+  if (trap.hasErrorOccurred() || findingAllocFuncFailed || !operatorNew ||
+      operatorNew->isDeleted() ||
       operatorNew->getAccess() == clang::AS_private ||
       operatorNew->getAccess() == clang::AS_protected)
-    return nullptr;
+    return {};
 
   clang::QualType cxxRecordPtrTy = clangCtx.getPointerType(cxxRecordTy);
   // Adding `_Nonnull` to the return type of synthesized static factory
   bool nullabilityCannotBeAdded =
       clangSema.CheckImplicitNullabilityTypeSpecifier(
-          cxxRecordPtrTy, clang::NullabilityKind::NonNull,
-          cxxRecordDecl->getLocation(),
-          /*isParam=*/false,
-          /*OverrideExisting=*/true);
+          cxxRecordPtrTy, clang::NullabilityKind::NonNull, cxxRecordDeclLoc,
+          /*isParam=*/false, /*OverrideExisting=*/true);
   assert(!nullabilityCannotBeAdded &&
          "Failed to add _Nonnull specifier to synthesized "
          "static factory's return type");
 
   clang::IdentifierTable &clangIdents = clangCtx.Idents;
-  clang::IdentifierInfo *funcNameToSynthesize = &clangIdents.get(
-      ("__returns_" + cxxRecordDecl->getNameAsString()).c_str());
-  clang::FunctionProtoType::ExtProtoInfo EPI;
-  clang::QualType funcTypeToSynthesize =
-      clangCtx.getFunctionType(cxxRecordPtrTy, {}, EPI);
-
-  clang::CXXMethodDecl *synthesizedCxxMethodDecl = clang::CXXMethodDecl::Create(
-      clangCtx, const_cast<clang::CXXRecordDecl *>(cxxRecordDecl),
-      cxxRecordDecl->getLocation(),
-      clang::DeclarationNameInfo(funcNameToSynthesize,
-                                 cxxRecordDecl->getLocation()),
-      funcTypeToSynthesize,
-      clangCtx.getTrivialTypeSourceInfo(funcTypeToSynthesize), clang::SC_Static,
-      /*UsesFPIntrin=*/false, /*isInline=*/true,
-      clang::ConstexprSpecKind::Unspecified, cxxRecordDecl->getLocation());
-  assert(synthesizedCxxMethodDecl &&
-         "Unable to synthesize static factory for c++ foreign reference type");
-  synthesizedCxxMethodDecl->setAccess(clang::AccessSpecifier::AS_public);
-
-  if (!hasImmortalAttrs(cxxRecordDecl)) {
-    clang::SwiftAttrAttr *returnsRetainedAttrForSynthesizedCxxMethodDecl =
-        clang::SwiftAttrAttr::Create(clangCtx, "returns_retained");
-    synthesizedCxxMethodDecl->addAttr(
-        returnsRetainedAttrForSynthesizedCxxMethodDecl);
+
+  llvm::SmallVector<clang::CXXMethodDecl *, 4> synthesizedFactories;
+  unsigned int selectedCtorDeclCounter = 0;
+  for (clang::CXXConstructorDecl *selectedCtorDecl : ctorDeclsForSynth) {
+    unsigned int ctorParamCount = selectedCtorDecl->getNumParams();
+    selectedCtorDeclCounter++;
+
+    std::string funcName = "__returns_" + cxxRecordDecl->getNameAsString();
+    if (ctorParamCount > 0)
+      funcName += "_" + std::to_string(ctorParamCount) + "_params";
+    funcName += "_" + std::to_string(selectedCtorDeclCounter);
+    clang::IdentifierInfo *funcNameToSynth = &clangIdents.get(funcName);
+
+    auto ctorFunctionProtoTy =
+        selectedCtorDecl->getType()->getAs<clang::FunctionProtoType>();
+    clang::ArrayRef<clang::QualType> paramTypes =
+        ctorFunctionProtoTy->getParamTypes();
+    clang::FunctionProtoType::ExtProtoInfo EPI;
+    clang::QualType funcTypeToSynth =
+        clangCtx.getFunctionType(cxxRecordPtrTy, paramTypes, EPI);
+
+    clang::CXXMethodDecl *synthCxxMethodDecl = clang::CXXMethodDecl::Create(
+        clangCtx, const_cast<clang::CXXRecordDecl *>(cxxRecordDecl),
+        cxxRecordDeclLoc,
+        clang::DeclarationNameInfo(funcNameToSynth, cxxRecordDeclLoc),
+        funcTypeToSynth, clangCtx.getTrivialTypeSourceInfo(funcTypeToSynth),
+        clang::SC_Static, /*UsesFPIntrin=*/false, /*isInline=*/true,
+        clang::ConstexprSpecKind::Unspecified, cxxRecordDeclLoc);
+    assert(
+        synthCxxMethodDecl &&
+        "Unable to synthesize static factory for c++ foreign reference type");
+    synthCxxMethodDecl->setAccess(clang::AccessSpecifier::AS_public);
+
+    llvm::SmallVector<clang::ParmVarDecl *, 4> synthParams;
+    for (unsigned int i = 0; i < ctorParamCount; ++i) {
+      auto *origParam = selectedCtorDecl->getParamDecl(i);
+      clang::IdentifierInfo *paramIdent = origParam->getIdentifier();
+      if (!paramIdent) {
+        std::string dummyName = "__unnamed_param_" + std::to_string(i);
+        paramIdent = &clangIdents.get(dummyName);
+      }
+      auto *param = clang::ParmVarDecl::Create(
+          clangCtx, synthCxxMethodDecl, cxxRecordDeclLoc, cxxRecordDeclLoc,
+          paramIdent, origParam->getType(),
+          clangCtx.getTrivialTypeSourceInfo(origParam->getType()),
+          clang::SC_None, /*DefArg=*/nullptr);
+      param->setIsUsed();
+      synthParams.push_back(param);
+    }
+    synthCxxMethodDecl->setParams(synthParams);
+
+    if (!hasImmortalAttrs(cxxRecordDecl)) {
+      synthCxxMethodDecl->addAttr(
+          clang::SwiftAttrAttr::Create(clangCtx, "returns_retained"));
+    }
+
+    std::string swiftInitStr = "init(";
+    for (unsigned i = 0; i < ctorParamCount; ++i) {
+      auto paramType = selectedCtorDecl->getParamDecl(i)->getType();
+      if (paramType->isRValueReferenceType()) {
+        swiftInitStr += "consuming:";
+      } else {
+        swiftInitStr += "_:";
+      }
+    }
+    swiftInitStr += ")";
+    synthCxxMethodDecl->addAttr(
+        clang::SwiftNameAttr::Create(clangCtx, swiftInitStr));
+
+    llvm::SmallVector<clang::Expr *, 4> ctorArgs;
+    for (auto *param : synthParams) {
+      clang::QualType paramTy = param->getType();
+      clang::QualType exprTy = paramTy.getNonReferenceType();
+      clang::Expr *argExpr = clang::DeclRefExpr::Create(
+          clangCtx, clang::NestedNameSpecifierLoc(), cxxRecordDeclLoc, param,
+          /*RefersToEnclosingVariableOrCapture=*/false, cxxRecordDeclLoc,
+          exprTy, clang::VK_LValue);
+      if (paramTy->isRValueReferenceType()) {
+        argExpr = clangSema
+                      .BuildCXXNamedCast(
+                          cxxRecordDeclLoc, clang::tok::kw_static_cast,
+                          clangCtx.getTrivialTypeSourceInfo(paramTy), argExpr,
+                          clang::SourceRange(), clang::SourceRange())
+                      .get();
+      }
+      ctorArgs.push_back(argExpr);
+    }
+    llvm::SmallVector<clang::Expr *, 4> ctorArgsToAdd;
+
+    if (clangSema.CompleteConstructorCall(selectedCtorDecl, cxxRecordTy,
+                                          ctorArgs, cxxRecordDeclLoc,
+                                          ctorArgsToAdd))
+      continue;
+
+    clang::ExprResult synthCtorExprResult = clangSema.BuildCXXConstructExpr(
+        cxxRecordDeclLoc, cxxRecordTy, selectedCtorDecl,
+        /*Elidable=*/false, ctorArgsToAdd,
+        /*HadMultipleCandidates=*/false,
+        /*IsListInitialization=*/false,
+        /*IsStdInitListInitialization=*/false,
+        /*RequiresZeroInit=*/false, clang::CXXConstructionKind::Complete,
+        clang::SourceRange(cxxRecordDeclLoc, cxxRecordDeclLoc));
+    assert(!synthCtorExprResult.isInvalid() &&
+           "Unable to synthesize constructor expression for c++ foreign "
+           "reference type");
+    clang::Expr *synthCtorExpr = synthCtorExprResult.get();
+
+    clang::ExprResult synthNewExprResult = clangSema.BuildCXXNew(
+        clang::SourceRange(), /*UseGlobal=*/false, clang::SourceLocation(), {},
+        clang::SourceLocation(), clang::SourceRange(), cxxRecordTy,
+        clangCtx.getTrivialTypeSourceInfo(cxxRecordTy), std::nullopt,
+        clang::SourceRange(cxxRecordDeclLoc, cxxRecordDeclLoc), synthCtorExpr);
+    assert(
+        !synthNewExprResult.isInvalid() &&
+        "Unable to synthesize `new` expression for c++ foreign reference type");
+    auto *synthNewExpr = cast<clang::CXXNewExpr>(synthNewExprResult.get());
+
+    clang::ReturnStmt *synthRetStmt = clang::ReturnStmt::Create(
+        clangCtx, cxxRecordDeclLoc, synthNewExpr, /*NRVOCandidate=*/nullptr);
+    assert(synthRetStmt && "Unable to synthesize return statement for "
+                           "static factory of c++ foreign reference type");
+
+    clang::CompoundStmt *synthFuncBody = clang::CompoundStmt::Create(
+        clangCtx, {synthRetStmt}, clang::FPOptionsOverride(), cxxRecordDeclLoc,
+        cxxRecordDeclLoc);
+    assert(synthRetStmt && "Unable to synthesize function body for static "
+                           "factory of c++ foreign reference type");
+
+    synthCxxMethodDecl->setBody(synthFuncBody);
+    synthCxxMethodDecl->addAttr(clang::NoDebugAttr::CreateImplicit(clangCtx));
+
+    synthCxxMethodDecl->setImplicit();
+    synthCxxMethodDecl->setImplicitlyInline();
+
+    synthesizedFactories.push_back(synthCxxMethodDecl);
   }
 
-  clang::SwiftNameAttr *swiftNameInitAttrForSynthesizedCxxMethodDecl =
-      clang::SwiftNameAttr::Create(clangCtx, "init()");
-  synthesizedCxxMethodDecl->addAttr(
-      swiftNameInitAttrForSynthesizedCxxMethodDecl);
-
-  clang::ExprResult synthesizedConstructExprResult =
-      clangSema.BuildCXXConstructExpr(
-          clang::SourceLocation(), cxxRecordTy, defaultCtorDecl,
-          /*Elidable=*/false, clang::MultiExprArg(),
-          /*HadMultipleCandidates=*/false,
-          /*IsListInitialization=*/false,
-          /*IsStdInitListInitialization=*/false,
-          /*RequiresZeroInit=*/false, clang::CXXConstructionKind::Complete,
-          clang::SourceRange());
-  assert(!synthesizedConstructExprResult.isInvalid() &&
-         "Unable to synthesize constructor expression for c++ foreign "
-         "reference type");
-  clang::CXXConstructExpr *synthesizedConstructExpr =
-      cast<clang::CXXConstructExpr>(synthesizedConstructExprResult.get());
-
-  clang::ExprResult synthesizedNewExprResult = clangSema.BuildCXXNew(
-      clang::SourceRange(), /*UseGlobal=*/false, clang::SourceLocation(), {},
-      clang::SourceLocation(), clang::SourceRange(), cxxRecordTy,
-      clangCtx.getTrivialTypeSourceInfo(cxxRecordTy), std::nullopt,
-      clang::SourceRange(), synthesizedConstructExpr);
-  assert(
-      !synthesizedNewExprResult.isInvalid() &&
-      "Unable to synthesize `new` expression for c++ foreign reference type");
-  clang::CXXNewExpr *synthesizedNewExpr =
-      cast<clang::CXXNewExpr>(synthesizedNewExprResult.get());
-
-  clang::ReturnStmt *synthesizedRetStmt =
-      clang::ReturnStmt::Create(clangCtx, clang::SourceLocation(),
-                                synthesizedNewExpr, /*VarDecl=*/nullptr);
-  assert(synthesizedRetStmt && "Unable to synthesize return statement for "
-                               "static factory of c++ foreign reference type");
-
-  clang::CompoundStmt *synthesizedFuncBody = clang::CompoundStmt::Create(
-      clangCtx, {synthesizedRetStmt}, clang::FPOptionsOverride(),
-      clang::SourceLocation(), clang::SourceLocation());
-  assert(synthesizedRetStmt && "Unable to synthesize function body for static "
-                               "factory of c++ foreign reference type");
-
-  synthesizedCxxMethodDecl->setBody(synthesizedFuncBody);
-  synthesizedCxxMethodDecl->addAttr(
-      clang::NoDebugAttr::CreateImplicit(clangCtx));
-
-  synthesizedCxxMethodDecl->setImplicit();
-  synthesizedCxxMethodDecl->setImplicitlyInline();
-
-  return synthesizedCxxMethodDecl;
+  return synthesizedFactories;
+}
+
+static std::pair<BraceStmt *, bool>
+synthesizeAvailabilityDomainPredicateBody(AbstractFunctionDecl *afd,
+                                          void *context) {
+  auto clangVarDecl = static_cast<const clang::VarDecl *>(context);
+  clang::ASTContext &clangCtx = clangVarDecl->getASTContext();
+  auto domainInfo =
+      clangCtx.getFeatureAvailInfo(const_cast<clang::VarDecl *>(clangVarDecl));
+  ASSERT(domainInfo.second.Call);
+
+  auto funcDecl = cast<FuncDecl>(afd);
+  ASTContext &ctx = funcDecl->getASTContext();
+
+  // FIXME: The need for an intermediate function to call could be eliminated if
+  // Clang provided the predicate function decl directly, rather than a call
+  // expression that must be wrapped in a function.
+  // Synthesize `return {domain predicate expression}`.
+  auto clangHelperReturnStmt = clang::ReturnStmt::Create(
+      clangCtx, clang::SourceLocation(), domainInfo.second.Call, nullptr);
+
+  // Synthesize `int __XYZ_isAvailable() { return {predicate expr}; }`.
+  auto clangDeclName = clang::DeclarationName(
+      &clangCtx.Idents.get("__" + domainInfo.first.str() + "_isAvailable"));
+  auto clangDeclContext = clangCtx.getTranslationUnitDecl();
+  clang::QualType funcTy =
+      clangCtx.getFunctionType(domainInfo.second.Call->getType(), {},
+                               clang::FunctionProtoType::ExtProtoInfo());
+
+  auto clangHelperFuncDecl = clang::FunctionDecl::Create(
+      clangCtx, clangDeclContext, clang::SourceLocation(),
+      clang::SourceLocation(), clangDeclName, funcTy,
+      clangCtx.getTrivialTypeSourceInfo(funcTy),
+      clang::StorageClass::SC_Static);
+  clangHelperFuncDecl->setImplicit();
+  clangHelperFuncDecl->setImplicitlyInline();
+  clangHelperFuncDecl->setBody(clangHelperReturnStmt);
+
+  // Import `func __XYZ_isAvailable() -> Bool` into Swift.
+  auto helperFuncDecl = dyn_cast_or_null<FuncDecl>(
+      ctx.getClangModuleLoader()->importDeclDirectly(clangHelperFuncDecl));
+  if (!helperFuncDecl)
+    return {nullptr, /*isTypeChecked=*/true};
+
+  auto helperFuncRef = new (ctx) DeclRefExpr(ConcreteDeclRef(helperFuncDecl),
+                                             DeclNameLoc(), /*Implicit=*/true);
+  helperFuncRef->setType(helperFuncDecl->getInterfaceType());
+
+  // Synthesize `__XYZ_isAvailable()`.
+  auto helperCall = CallExpr::createImplicit(
+      ctx, helperFuncRef, ArgumentList::createImplicit(ctx, {}));
+  helperCall->setType(helperFuncDecl->getResultInterfaceType());
+  helperCall->setThrows(nullptr);
+
+  // Synthesize `__XYZ_isAvailable()._value`.
+  auto *memberRef =
+      UnresolvedDotExpr::createImplicit(ctx, helperCall, ctx.Id_value_);
+
+  // Synthesize `return __XYZ_isAvailable()._value`.
+  auto *returnStmt = ReturnStmt::createImplicit(ctx, memberRef);
+  auto body = BraceStmt::create(ctx, SourceLoc(), {returnStmt}, SourceLoc(),
+                                /*implicit=*/true);
+
+  return {body, /*isTypeChecked=*/false};
+}
+
+/// Mark the given declaration as always deprecated for the given reason.
+static void markDeprecated(Decl *decl, llvm::Twine message) {
+  ASTContext &ctx = decl->getASTContext();
+  decl->getAttrs().add(
+      AvailableAttr::createUniversallyDeprecated(
+        ctx, ctx.AllocateCopy(message.str())));
+}
+
+static bool copyConstructorIsDefaulted(const clang::CXXRecordDecl *decl) {
+  auto ctor = llvm::find_if(decl->ctors(), [](clang::CXXConstructorDecl *ctor) {
+    return ctor->isCopyConstructor();
+  });
+
+  assert(ctor != decl->ctor_end());
+  return ctor->isDefaulted();
+}
+
+static bool copyAssignOperatorIsDefaulted(const clang::CXXRecordDecl *decl) {
+  auto copyAssignOp = llvm::find_if(decl->decls(), [](clang::Decl *member) {
+    if (auto method = dyn_cast<clang::CXXMethodDecl>(member))
+      return method->isCopyAssignmentOperator();
+    return false;
+  });
+
+  assert(copyAssignOp != decl->decls_end());
+  return cast<clang::CXXMethodDecl>(*copyAssignOp)->isDefaulted();
+}
+
+/// Recursively checks that there are no user-provided copy constructors or
+/// destructors in any fields or base classes.
+/// Does not check C++ records with specific API annotations.
+static bool isSufficientlyTrivial(const clang::CXXRecordDecl *decl) {
+  // Probably a class template that has not yet been specialized:
+  if (!decl->getDefinition())
+    return true;
+
+  if ((decl->hasUserDeclaredCopyConstructor() &&
+       !copyConstructorIsDefaulted(decl)) ||
+      (decl->hasUserDeclaredCopyAssignment() &&
+       !copyAssignOperatorIsDefaulted(decl)) ||
+      (decl->hasUserDeclaredDestructor() && decl->getDestructor() &&
+       !decl->getDestructor()->isDefaulted()))
+    return false;
+
+  auto checkType = [](clang::QualType t) {
+    if (auto recordType = dyn_cast<clang::RecordType>(t.getCanonicalType())) {
+      if (auto cxxRecord =
+              dyn_cast<clang::CXXRecordDecl>(recordType->getDecl())) {
+        if (hasImportAsRefAttr(cxxRecord) || hasOwnedValueAttr(cxxRecord) ||
+            hasUnsafeAPIAttr(cxxRecord))
+          return true;
+
+        if (!isSufficientlyTrivial(cxxRecord))
+          return false;
+      }
+    }
+
+    return true;
+  };
+
+  for (auto field : decl->fields()) {
+    if (!checkType(field->getType()))
+      return false;
+  }
+
+  for (auto base : decl->bases()) {
+    if (!checkType(base.getType()))
+      return false;
+  }
+
+  return true;
+}
+
+/// Find an explicitly-provided "destroy" operation specified for the
+/// given Clang type and return it.
+FuncDecl *SwiftDeclSynthesizer::findExplicitDestroy(
+    NominalTypeDecl *nominal, const clang::RecordDecl *clangType) {
+  if (!clangType->hasAttrs())
+    return nullptr;
+
+  llvm::SmallPtrSet<FuncDecl *, 2> matchingDestroyFuncs;
+  llvm::TinyPtrVector<FuncDecl *> nonMatchingDestroyFuncs;
+  for (auto attr : clangType->getAttrs()) {
+    auto swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr);
+    if (!swiftAttr)
+      continue;
+
+    auto destroyFuncName = swiftAttr->getAttribute();
+    if (!destroyFuncName.consume_front("destroy:"))
+      continue;
+
+    auto decls = getValueDeclsForName(nominal, destroyFuncName);
+    for (auto decl : decls) {
+      auto func = dyn_cast<FuncDecl>(decl);
+      if (!func)
+        continue;
+
+      auto params = func->getParameters();
+      if (params->size() != 1) {
+        nonMatchingDestroyFuncs.push_back(func);
+        continue;
+      }
+
+      if (!params->get(0)->getInterfaceType()->isEqual(
+              nominal->getDeclaredInterfaceType())) {
+        nonMatchingDestroyFuncs.push_back(func);
+        continue;
+      }
+
+      matchingDestroyFuncs.insert(func);
+    }
+  }
+
+  switch (matchingDestroyFuncs.size()) {
+  case 0:
+    if (!nonMatchingDestroyFuncs.empty()) {
+      markDeprecated(
+          nominal,
+          "destroy function '" +
+           nonMatchingDestroyFuncs.front()->getName().getBaseName()
+             .userFacingName() +
+           "' must have a single parameter with type '" +
+           nominal->getDeclaredInterfaceType().getString() + "'");
+    }
+
+    return nullptr;
+
+  case 1:
+    // Handled below.
+    break;
+
+  default: {
+    auto iter = matchingDestroyFuncs.begin();
+    auto first = *iter++;
+    auto second = *iter;
+    markDeprecated(
+        nominal,
+        "multiple destroy operations ('" +
+          first->getName().getBaseName().userFacingName() +
+          "' and '" +
+          second->getName().getBaseName().userFacingName() +
+          "') provided for type");
+    return nullptr;
+  }
+  }
+
+  auto destroyFunc = *matchingDestroyFuncs.begin();
+
+  // If this type isn't imported as noncopyable, we can't respect the request
+  // for a destroy operation.
+  ASTContext &ctx = ImporterImpl.SwiftContext;
+  auto valueSemanticsKind = evaluateOrDefault(
+      ctx.evaluator, 
+      CxxValueSemantics({clangType->getTypeForDecl(), &ImporterImpl}), {});
+
+  if (valueSemanticsKind != CxxValueSemanticsKind::Copyable &&
+      valueSemanticsKind != CxxValueSemanticsKind::MoveOnly)
+    return nullptr;
+
+  auto cxxRecordSemanticsKind = evaluateOrDefault(
+      ctx.evaluator, CxxRecordSemantics({clangType, ctx, &ImporterImpl}), {});
+  switch (cxxRecordSemanticsKind) {
+  case CxxRecordSemanticsKind::Value:
+  case CxxRecordSemanticsKind::Reference:
+    if (auto cxxRecord = dyn_cast<clang::CXXRecordDecl>(clangType)) {
+      if (!isSufficientlyTrivial(cxxRecord)) {
+        markDeprecated(
+            nominal,
+            "destroy operation '" +
+              destroyFunc->getName().getBaseName().userFacingName() +
+              "' is not allowed on types with a non-trivial destructor");
+        return nullptr;
+      }
+    }
+
+    if (valueSemanticsKind == CxxValueSemanticsKind::MoveOnly)
+      return destroyFunc;
+
+    markDeprecated(
+        nominal,
+        "destroy operation '" +
+          destroyFunc->getName().getBaseName().userFacingName() +
+          "' is only allowed on non-copyable types; "
+          "did you mean to use SWIFT_NONCOPYABLE?");
+    return nullptr;
+
+  case CxxRecordSemanticsKind::Iterator:
+  case CxxRecordSemanticsKind::SwiftClassType:
+    return nullptr;
+  }
+}
+
+/// Function body synthesizer for a deinit of a noncopyable type, which
+/// passes "self" to the given "destroy" function.
+static std::pair<BraceStmt *, bool>
+synthesizeDeinitBodyForCustomDestroy(
+    AbstractFunctionDecl *deinitFunc, void *opaqueDestroyFunc) {
+  auto deinit = cast<DestructorDecl>(deinitFunc);
+  auto destroyFunc = static_cast<FuncDecl *>(opaqueDestroyFunc);
+
+  ASTContext &ctx = deinit->getASTContext();
+  auto funcRef = new (ctx) DeclRefExpr(
+      destroyFunc, DeclNameLoc(), /*Implicit=*/true);
+  auto selfRef = new (ctx) DeclRefExpr(
+      deinit->getImplicitSelfDecl(), DeclNameLoc(), /*Implicit=*/true);
+  auto callExpr = CallExpr::createImplicit(
+      ctx, funcRef,
+      ArgumentList::createImplicit(
+        ctx,
+        { Argument(SourceLoc(), Identifier(), selfRef)}
+      )
+  );
+
+  auto braceStmt = BraceStmt::createImplicit(ctx, { ASTNode(callExpr) });
+  return std::make_pair(braceStmt, /*typechecked=*/false);
+}
+
+void SwiftDeclSynthesizer::addExplicitDeinitIfRequired(
+    NominalTypeDecl *nominal, const clang::RecordDecl *clangType) {
+  auto destroyFunc = findExplicitDestroy(nominal, clangType);
+  if (!destroyFunc)
+    return;
+
+  ASTContext &ctx = nominal->getASTContext();
+  auto destructor = new (ctx) DestructorDecl(SourceLoc(), nominal);
+  destructor->setSynthesized(true);
+  destructor->copyFormalAccessFrom(nominal, /*sourceIsParentContext*/true);
+  destructor->setBodySynthesizer(
+      synthesizeDeinitBodyForCustomDestroy, destroyFunc);
+
+  nominal->addMember(destructor);
+}
+
+FuncDecl *SwiftDeclSynthesizer::makeAvailabilityDomainPredicate(
+    const clang::VarDecl *var) {
+  ASTContext &ctx = ImporterImpl.SwiftContext;
+  clang::ASTContext &clangCtx = var->getASTContext();
+  auto featureInfo =
+      clangCtx.getFeatureAvailInfo(const_cast<clang::VarDecl *>(var));
+
+  // If the decl doesn't represent and availability domain, skip it.
+  if (featureInfo.first.empty())
+    return nullptr;
+
+  // Only dynamic availability domains require a predicate function.
+  if (featureInfo.second.Kind != clang::FeatureAvailKind::Dynamic)
+    return nullptr;
+
+  if (!featureInfo.second.Call)
+    return nullptr;
+
+  // Synthesize `func __swift_XYZ_isAvailable() -> Builtin.Int1 { ... }`.
+  std::string s;
+  llvm::raw_string_ostream os(s);
+  os << "__swift_" << featureInfo.first << "_isAvailable";
+  DeclName funcName(ctx, DeclBaseName(ctx.getIdentifier(s)),
+                    ParameterList::createEmpty(ctx));
+
+  auto funcDecl = FuncDecl::createImplicit(
+      ctx, StaticSpellingKind::None, funcName, SourceLoc(), /*Async=*/false,
+      /*Throws=*/false, Type(), {}, ParameterList::createEmpty(ctx),
+      BuiltinIntegerType::get(1, ctx), ImporterImpl.ImportedHeaderUnit);
+  funcDecl->setBodySynthesizer(synthesizeAvailabilityDomainPredicateBody,
+                               (void *)var);
+  funcDecl->setAccess(AccessLevel::Public);
+  funcDecl->getAttrs().add(new (ctx)
+                               AlwaysEmitIntoClientAttr(/*IsImplicit=*/true));
+
+  ImporterImpl.availabilityDomainPredicates[var] = funcDecl;
+
+  return funcDecl;
 }
diff --git a/lib/ClangImporter/SwiftDeclSynthesizer.h b/lib/ClangImporter/SwiftDeclSynthesizer.h
index 9fab97a4e7b0e..8ca3eaec128e4 100644
--- a/lib/ClangImporter/SwiftDeclSynthesizer.h
+++ b/lib/ClangImporter/SwiftDeclSynthesizer.h
@@ -1,4 +1,4 @@
-//===--- DeclSynthesizer.h - Synthesize helper Swift decls ------*- C++ -*-===//
+//===--- SwiftDeclSynthesizer.h - Synthesize helper Swift decls -*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -322,7 +322,8 @@ class SwiftDeclSynthesizer {
 
   /// Given an overload of a C++ virtual method on a reference type, create a
   /// method that dispatches the call dynamically.
-  FuncDecl *makeVirtualMethod(const clang::CXXMethodDecl *clangMethodDecl);
+  FuncDecl *makeVirtualMethod(const clang::CXXMethodDecl *clangMethodDecl,
+                              StringRef swiftName);
 
   FuncDecl *makeInstanceToStaticOperatorCallMethod(
       const clang::CXXMethodDecl *clangMethodDecl);
@@ -337,11 +338,34 @@ class SwiftDeclSynthesizer {
   /// Synthesize a static factory method for a C++ foreign reference type,
   /// returning a `CXXMethodDecl*` or `nullptr` if the required constructor or
   /// allocation function is not found.
-  clang::CXXMethodDecl *synthesizeStaticFactoryForCXXForeignRef(
+  llvm::SmallVector<clang::CXXMethodDecl *, 4>
+  synthesizeStaticFactoryForCXXForeignRef(
       const clang::CXXRecordDecl *cxxRecordDecl);
 
+  /// Look for an explicitly-provided "destroy" operation. If one exists
+  /// and the type has been imported as noncopyable, add an explicit `deinit`
+  /// that calls that destroy operation.
+  void addExplicitDeinitIfRequired(
+      NominalTypeDecl *nominal, const clang::RecordDecl *clangType);
+
+  /// Synthesize a Swift function that calls the Clang runtime predicate
+  /// function for the availability domain represented by `var`.
+  FuncDecl *makeAvailabilityDomainPredicate(const clang::VarDecl *var);
+
+  bool isCGFloat(Type type);
+
+  bool isObjCBool(Type type);
+
+  bool isUnicodeScalar(Type type);
+
 private:
   Type getConstantLiteralType(Type type, ConstantConvertKind convertKind);
+
+  /// Find an explicitly-provided "destroy" operation specified for the
+  /// given Clang type and return it.
+  FuncDecl *findExplicitDestroy(
+      NominalTypeDecl *nominal, const clang::RecordDecl *clangType);
+
 };
 
 } // namespace swift
diff --git a/lib/ClangImporter/SwiftLookupTable.cpp b/lib/ClangImporter/SwiftLookupTable.cpp
index 92ce51f81e857..235e9531d7af0 100644
--- a/lib/ClangImporter/SwiftLookupTable.cpp
+++ b/lib/ClangImporter/SwiftLookupTable.cpp
@@ -22,6 +22,7 @@
 #include "swift/Basic/STLExtras.h"
 #include "swift/Basic/Version.h"
 #include "swift/ClangImporter/ClangImporter.h"
+#include "swift/Parse/ParseDeclName.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/Lex/MacroInfo.h"
@@ -64,7 +65,6 @@ namespace {
 
   class BaseNameToEntitiesTableReaderInfo;
   class GlobalsAsMembersTableReaderInfo;
-  class AvailabilityDomainsTableReaderInfo;
 
   using SerializedBaseNameToEntitiesTable =
     llvm::OnDiskIterableChainedHashTable<BaseNameToEntitiesTableReaderInfo>;
@@ -74,9 +74,6 @@ namespace {
 
   using SerializedGlobalsAsMembersIndex =
     llvm::OnDiskIterableChainedHashTable<GlobalsAsMembersTableReaderInfo>;
-
-  using SerializedAvailabilityDomainsTable =
-      llvm::OnDiskIterableChainedHashTable<AvailabilityDomainsTableReaderInfo>;
 } // end anonymous namespace
 
 namespace swift {
@@ -118,8 +115,6 @@ class SwiftLookupTableReader : public clang::ModuleFileExtensionReader {
 
   std::unique_ptr<SerializedBaseNameToEntitiesTable> SerializedTable;
   ArrayRef<clang::serialization::DeclID> Categories;
-  // FIXME: [availability] Remove this when Clang supports domain lookup.
-  std::unique_ptr<SerializedAvailabilityDomainsTable> AvailabilityDomainsTable;
   std::unique_ptr<SerializedGlobalsAsMembersTable> GlobalsAsMembersTable;
   std::unique_ptr<SerializedGlobalsAsMembersIndex> GlobalsAsMembersIndex;
 
@@ -130,8 +125,6 @@ class SwiftLookupTableReader : public clang::ModuleFileExtensionReader {
                          std::unique_ptr<SerializedBaseNameToEntitiesTable>
                              serializedTable,
                          ArrayRef<clang::serialization::DeclID> categories,
-                         std::unique_ptr<SerializedAvailabilityDomainsTable>
-                             availabilityDomainsTable,
                          std::unique_ptr<SerializedGlobalsAsMembersTable>
                              globalsAsMembersTable,
                          std::unique_ptr<SerializedGlobalsAsMembersIndex>
@@ -139,7 +132,6 @@ class SwiftLookupTableReader : public clang::ModuleFileExtensionReader {
       : ModuleFileExtensionReader(extension), Reader(reader),
         ModuleFile(moduleFile), OnRemove(onRemove),
         SerializedTable(std::move(serializedTable)), Categories(categories),
-        AvailabilityDomainsTable(std::move(availabilityDomainsTable)),
         GlobalsAsMembersTable(std::move(globalsAsMembersTable)),
         GlobalsAsMembersIndex(std::move(globalsAsMembersIndex)) {}
 
@@ -194,12 +186,6 @@ class SwiftLookupTableReader : public clang::ModuleFileExtensionReader {
   bool lookupGlobalsAsMembers(
       SerializedSwiftName baseName,
       SmallVectorImpl<SwiftLookupTable::FullTableEntry> &entries);
-
-  SmallVector<StringRef, 4> getAvailabilityDomainNames();
-
-  /// Retreve the decl ID representing the availability domain with the given
-  /// name.
-  clang::serialization::DeclID lookupAvailabilityDomain(StringRef domainName);
 };
 } // namespace swift
 
@@ -234,7 +220,7 @@ bool SwiftLookupTable::contextRequiresName(ContextKind kind) {
 
 /// Try to translate the given Clang declaration into a context.
 static std::optional<SwiftLookupTable::StoredContext>
-translateDeclToContext(clang::NamedDecl *decl) {
+translateDeclToContext(const clang::NamedDecl *decl) {
   // Tag declaration.
   if (auto tag = dyn_cast<clang::TagDecl>(decl)) {
     if (tag->getIdentifier())
@@ -339,22 +325,49 @@ SwiftLookupTable::translateContext(EffectiveClangContext context) {
 
 /// Lookup an unresolved context name and resolve it to a Clang
 /// declaration context or typedef name.
-clang::NamedDecl *SwiftLookupTable::resolveContext(StringRef unresolvedName) {
+const clang::NamedDecl *
+SwiftLookupTable::resolveContext(StringRef unresolvedName) {
+  SmallVector<StringRef, 1> nameComponents;
+  unresolvedName.split(nameComponents, '.');
+
+  EffectiveClangContext parentContext;
+
   // Look for a context with the given Swift name.
-  for (auto entry :
-       lookup(SerializedSwiftName(unresolvedName),
-              std::make_pair(ContextKind::TranslationUnit, StringRef()))) {
-    if (auto decl = entry.dyn_cast<clang::NamedDecl *>()) {
-      if (isa<clang::TagDecl>(decl) ||
-          isa<clang::ObjCInterfaceDecl>(decl) ||
-          isa<clang::TypedefNameDecl>(decl))
-        return decl;
+  for (auto nameComponent : nameComponents) {
+    auto entries =
+        parentContext
+            ? lookup(SerializedSwiftName(nameComponent), parentContext)
+            : lookup(SerializedSwiftName(nameComponent),
+                     std::make_pair(ContextKind::TranslationUnit, StringRef()));
+    bool entryFound = false;
+    for (auto entry : entries) {
+      if (auto decl = entry.dyn_cast<clang::NamedDecl *>()) {
+        if (isa<clang::TagDecl>(decl) ||
+            isa<clang::ObjCInterfaceDecl>(decl) ||
+            isa<clang::NamespaceDecl>(decl)) {
+          entryFound = true;
+          parentContext = EffectiveClangContext(cast<clang::DeclContext>(decl));
+          break;
+        }
+        if (auto typedefDecl = dyn_cast<clang::TypedefNameDecl>(decl)) {
+          entryFound = true;
+          parentContext = EffectiveClangContext(typedefDecl);
+          break;
+        }
+      }
     }
-  }
 
-  // FIXME: Search imported modules to resolve the context.
+    // If we could not resolve this component of the qualified name, bail.
+    if (!entryFound)
+      break;
+  }
+  
+  if (!parentContext)
+    return nullptr;
 
-  return nullptr;
+  return parentContext.getAsDeclContext()
+             ? cast<clang::NamedDecl>(parentContext.getAsDeclContext())
+             : parentContext.getTypedefName();
 }
 
 void SwiftLookupTable::addCategory(clang::ObjCCategoryDecl *category) {
@@ -365,11 +378,6 @@ void SwiftLookupTable::addCategory(clang::ObjCCategoryDecl *category) {
   Categories.push_back(category);
 }
 
-void SwiftLookupTable::addAvailabilityDomainDecl(StringRef name,
-                                                 clang::VarDecl *decl) {
-  AvailabilityDomains.insert({name, decl});
-}
-
 bool SwiftLookupTable::resolveUnresolvedEntries(
     SmallVectorImpl<SingleEntry> &unresolved) {
   // Common case: nothing left to resolve.
@@ -454,10 +462,11 @@ static bool isGlobalAsMember(SwiftLookupTable::SingleEntry entry,
 
   // Macros are never stored within a non-translation-unit context in
   // Clang.
-  if (entry.is<clang::MacroInfo *>()) return true;
+  if (isa<clang::MacroInfo *>(entry))
+    return true;
 
   // We have a declaration.
-  auto decl = entry.get<clang::NamedDecl *>();
+  auto *decl = cast<clang::NamedDecl *>(entry);
 
   // Enumerators have the translation unit as their redeclaration context,
   // but members of anonymous enums are still allowed to be in the
@@ -506,7 +515,7 @@ bool SwiftLookupTable::addLocalEntry(
     if (moduleMacro && existingEntry.isMacroEntry()) {
       SingleEntry decodedEntry = mapStoredMacro(existingEntry,
                                                 /*assumeModule*/true);
-      const auto *existingMacro = decodedEntry.get<clang::ModuleMacro *>();
+      const auto *existingMacro = cast<clang::ModuleMacro *>(decodedEntry);
 
       const clang::Module *newModule = moduleMacro->getOwningModule();
       const clang::Module *existingModule = existingMacro->getOwningModule();
@@ -546,7 +555,7 @@ void SwiftLookupTable::addEntry(DeclName name, SingleEntry newEntry,
   auto contextOpt = translateContext(effectiveContext);
   if (!contextOpt) {
     // We might be able to resolve this later.
-    if (newEntry.is<clang::NamedDecl *>()) {
+    if (isa<clang::NamedDecl *>(newEntry)) {
       UnresolvedEntries.push_back(
         std::make_tuple(name, newEntry, effectiveContext));
     }
@@ -732,38 +741,6 @@ SwiftLookupTable::lookupGlobalsAsMembers(SerializedSwiftName baseName,
   return lookupGlobalsAsMembersImpl(baseName, *storedContext);
 }
 
-// FIXME: [availability] Remove this once Clang has a lookup table.
-clang::VarDecl *SwiftLookupTable::lookupAvailabilityDomainDecl(StringRef name) {
-  // If the name is empty, there is nothing to find.
-  if (name.empty())
-    return nullptr;
-
-  // See if we have an existing cached lookup result.
-  auto known = AvailabilityDomains.find(name);
-  if (known != AvailabilityDomains.end())
-    return known->second;
-
-  // If there's no reader, we've found all there is to find.
-  if (!Reader)
-    return nullptr;
-
-  // Look up this domain in the module file.
-  clang::VarDecl *result = nullptr;
-  auto declID = Reader->lookupAvailabilityDomain(name);
-  if (declID) {
-    auto localID = clang::LocalDeclID::get(Reader->getASTReader(),
-                                           Reader->getModuleFile(), declID);
-    result = cast_or_null<clang::VarDecl>(
-        Reader->getASTReader().GetLocalDecl(Reader->getModuleFile(), localID));
-  }
-
-  // Add the result to the table (whether we found a decl or not) so that we
-  // don't look again.
-  AvailabilityDomains.insert({name, result});
-
-  return result;
-}
-
 SmallVector<SwiftLookupTable::SingleEntry, 4>
 SwiftLookupTable::allGlobalsAsMembersInContext(EffectiveClangContext context) {
   if (!context) return { };
@@ -972,10 +949,6 @@ void SwiftLookupTable::deserializeAll() {
   for (auto context : Reader->getGlobalsAsMembersContexts()) {
     (void)allGlobalsAsMembersInContext(context);
   }
-
-  for (auto domainName : Reader->getAvailabilityDomainNames()) {
-    (void)lookupAvailabilityDomainDecl(domainName);
-  }
 }
 
 /// Print a stored context to the given output stream for debugging purposes.
@@ -1106,22 +1079,6 @@ void SwiftLookupTable::dump(raw_ostream &os) const {
       os << "\n";
     }
   }
-
-  if (!AvailabilityDomains.empty()) {
-    os << "Availability domains:\n";
-    SmallVector<StringRef, 4> domainNames;
-    for (const auto &entry : AvailabilityDomains) {
-      domainNames.push_back(entry.first);
-    }
-    llvm::array_pod_sort(domainNames.begin(), domainNames.end());
-
-    for (auto domainName : domainNames) {
-      os << "  " << domainName << ": ";
-
-      auto *domainDecl = AvailabilityDomains.find(domainName)->second;
-      os << (domainDecl ? domainDecl->getName() : "<nullptr>") << "\n";
-    }
-  }
 }
 
 // ---------------------------------------------------------------------------
@@ -1151,10 +1108,6 @@ namespace {
     /// Record that contains the mapping from contexts to the list of
     /// globals that will be injected as members into those contexts.
     GLOBALS_AS_MEMBERS_INDEX_RECORD_ID,
-
-    // FIXME: [availability] Remove this when Clang supports domain lookup.
-    /// Record that contains the mapping from domain names to domain decls.
-    AVAILABILITY_DOMAINS_ID,
   };
 
   using BaseNameToEntitiesTableRecordLayout
@@ -1169,9 +1122,6 @@ namespace {
   using GlobalsAsMembersIndexRecordLayout
     = BCRecordLayout<GLOBALS_AS_MEMBERS_INDEX_RECORD_ID, BCVBR<16>, BCBlob>;
 
-  using AvailabilityDomainsTableRecordLayout =
-      BCRecordLayout<AVAILABILITY_DOMAINS_ID, BCVBR<16>, BCBlob>;
-
   constexpr size_t SizeOfEmittedStoredSingleEntry
     = sizeof(StoredSingleEntry::SerializationID)
       + sizeof(StoredSingleEntry::SubmoduleID);
@@ -1186,9 +1136,10 @@ namespace {
       ids = StoredSingleEntry::forSerializedDecl(
                                  astWriter.getDeclID(decl).getRawValue());
     } else if (auto *macro = mappedEntry.dyn_cast<clang::MacroInfo *>()) {
-      ids = StoredSingleEntry::forSerializedMacro(astWriter.getMacroID(macro));
+      ids = StoredSingleEntry::forSerializedMacro(
+          astWriter.getMacroRef(macro, /*Name=*/nullptr));
     } else {
-      auto *moduleMacro = mappedEntry.get<clang::ModuleMacro *>();
+      auto *moduleMacro = cast<clang::ModuleMacro *>(mappedEntry);
       StoredSingleEntry::SerializationID nameID =
         astWriter.getIdentifierRef(moduleMacro->getName());
       StoredSingleEntry::SubmoduleID submoduleID =
@@ -1367,38 +1318,6 @@ namespace {
     }
   };
 
-  // FIXME: [availability] Remove this when Clang supports domain lookup.
-  /// Trait used to write the on-disk hash table for the identifier ->
-  /// availability domain table.
-  class AvailabilityDomainsTableWriterInfo {
-  public:
-    using key_type = StringRef;
-    using key_type_ref = key_type;
-    using data_type = clang::serialization::DeclID;
-    using data_type_ref = const data_type &;
-    using hash_value_type = uint32_t;
-    using offset_type = unsigned;
-
-    hash_value_type ComputeHash(key_type_ref key) { return llvm::djbHash(key); }
-
-    std::pair<unsigned, unsigned>
-    EmitKeyDataLength(raw_ostream &os, key_type_ref key, data_type_ref) {
-      uint32_t keyLength = key.size();
-      uint32_t dataLength = sizeof(data_type);
-
-      llvm::support::endian::Writer writer(os, llvm::endianness::little);
-      writer.write<uint16_t>(keyLength);
-      writer.write<uint16_t>(dataLength);
-      return {keyLength, dataLength};
-    }
-
-    void EmitKey(raw_ostream &os, key_type_ref key, unsigned) { os << key; }
-
-    void EmitData(raw_ostream &os, key_type_ref, data_type_ref data, unsigned) {
-      llvm::support::endian::Writer writer(os, llvm::endianness::little);
-      writer.write<data_type>(data);
-    }
-  };
 } // end anonymous namespace
 
 void SwiftLookupTableWriter::writeExtensionContents(
@@ -1510,35 +1429,6 @@ void SwiftLookupTableWriter::writeExtensionContents(
     GlobalsAsMembersIndexRecordLayout layout(stream);
     layout.emit(ScratchRecord, tableOffset, hashTableBlob);
   }
-
-  if (!table.AvailabilityDomains.empty()) {
-    // Sort the availability domain names.
-    SmallVector<StringRef, 4> domainNames;
-    for (const auto &entry : table.AvailabilityDomains)
-      domainNames.push_back(entry.first);
-    llvm::array_pod_sort(domainNames.begin(), domainNames.end());
-
-    llvm::SmallString<4096> hashTableBlob;
-    uint32_t tableOffset;
-    {
-      llvm::OnDiskChainedHashTableGenerator<AvailabilityDomainsTableWriterInfo>
-          generator;
-      AvailabilityDomainsTableWriterInfo info;
-
-      for (auto domainName : domainNames) {
-        auto domainDecl = table.AvailabilityDomains[domainName];
-        auto declID = Writer.getDeclID(domainDecl).getRawValue();
-        generator.insert(domainName, declID, info);
-      }
-
-      llvm::raw_svector_ostream blobStream(hashTableBlob);
-      // Make sure that no bucket is at offset 0
-      endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
-      tableOffset = generator.Emit(blobStream, info);
-    }
-    AvailabilityDomainsTableRecordLayout layout(stream);
-    layout.emit(ScratchRecord, tableOffset, hashTableBlob);
-  }
 }
 
 namespace {
@@ -1690,46 +1580,6 @@ namespace {
     }
   };
 
-  // FIXME: [availability] Remove this when Clang supports domain lookup.
-  /// Used to deserialize the on-disk identifier -> availability domain table.
-  class AvailabilityDomainsTableReaderInfo {
-  public:
-    using internal_key_type = llvm::StringRef;
-    using external_key_type = internal_key_type;
-    using data_type = clang::serialization::DeclID;
-    using hash_value_type = uint32_t;
-    using offset_type = unsigned;
-
-    internal_key_type GetInternalKey(external_key_type key) { return key; }
-    external_key_type GetExternalKey(internal_key_type key) { return key; }
-
-    hash_value_type ComputeHash(internal_key_type key) {
-      return llvm::djbHash(key);
-    }
-
-    static bool EqualKey(internal_key_type lhs, internal_key_type rhs) {
-      return lhs == rhs;
-    }
-
-    static std::pair<unsigned, unsigned>
-    ReadKeyDataLength(const uint8_t *&data) {
-      unsigned keyLength =
-          endian::readNext<uint16_t, llvm::endianness::little>(data);
-      unsigned dataLength =
-          endian::readNext<uint16_t, llvm::endianness::little>(data);
-      return {keyLength, dataLength};
-    }
-
-    static internal_key_type ReadKey(const uint8_t *data, unsigned length) {
-      return llvm::StringRef(reinterpret_cast<const char *>(data), length);
-    }
-
-    static data_type ReadData(internal_key_type key, const uint8_t *data,
-                              unsigned length) {
-      return endian::readNext<data_type, llvm::endianness::little>(data);
-    }
-  };
-
 } // end anonymous namespace
 
 clang::NamedDecl *SwiftLookupTable::mapStoredDecl(StoredSingleEntry &entry) {
@@ -1839,7 +1689,6 @@ SwiftLookupTableReader::create(clang::ModuleFileExtension *extension,
   std::unique_ptr<SerializedGlobalsAsMembersIndex> globalsAsMembersIndex;
   std::unique_ptr<SerializedGlobalsAsMembersTable> globalsAsMembersTable;
   ArrayRef<clang::serialization::DeclID> categories;
-  std::unique_ptr<SerializedAvailabilityDomainsTable> availabilityDomainsTable;
 
   while (next.Kind != llvm::BitstreamEntry::EndBlock) {
     if (next.Kind == llvm::BitstreamEntry::Error)
@@ -1932,20 +1781,6 @@ SwiftLookupTableReader::create(clang::ModuleFileExtension *extension,
       break;
     }
 
-    case AVAILABILITY_DOMAINS_ID: {
-      // Already saw the availability domains table.
-      if (availabilityDomainsTable)
-        return nullptr;
-
-      uint32_t tableOffset;
-      AvailabilityDomainsTableRecordLayout::readRecord(scratch, tableOffset);
-      auto base = reinterpret_cast<const uint8_t *>(blobData.data());
-
-      availabilityDomainsTable.reset(SerializedAvailabilityDomainsTable::Create(
-          base + tableOffset, base + sizeof(uint32_t), base));
-      break;
-    }
-
     default:
       // Unknown record, possibly for use by a future version of the
       // module format.
@@ -1969,7 +1804,6 @@ SwiftLookupTableReader::create(clang::ModuleFileExtension *extension,
   return std::unique_ptr<SwiftLookupTableReader>(
            new SwiftLookupTableReader(extension, reader, moduleFile, onRemove,
                                       std::move(serializedTable), categories,
-                                      std::move(availabilityDomainsTable),
                                       std::move(globalsAsMembersTable),
                                       std::move(globalsAsMembersIndex)));
 
@@ -2045,30 +1879,6 @@ bool SwiftLookupTableReader::lookupGlobalsAsMembers(
   return true;
 }
 
-SmallVector<StringRef, 4> SwiftLookupTableReader::getAvailabilityDomainNames() {
-  SmallVector<StringRef, 4> results;
-  if (!AvailabilityDomainsTable)
-    return {};
-
-  for (auto name : AvailabilityDomainsTable->keys()) {
-    results.push_back(name);
-  }
-  return results;
-}
-
-clang::serialization::DeclID
-SwiftLookupTableReader::lookupAvailabilityDomain(StringRef domainName) {
-  if (!AvailabilityDomainsTable)
-    return {};
-
-  // Look for an entry with this context name.
-  auto known = AvailabilityDomainsTable->find(domainName);
-  if (known == AvailabilityDomainsTable->end())
-    return {};
-
-  return *known;
-}
-
 clang::ModuleFileExtensionMetadata
 SwiftNameLookupExtension::getExtensionMetadata() const {
   clang::ModuleFileExtensionMetadata metadata;
@@ -2100,19 +1910,9 @@ void importer::addEntryToLookupTable(SwiftLookupTable &table,
   if (shouldSuppressDeclImport(named))
     return;
 
-  // Leave incomplete struct/enum/union types out of the table; Swift only
-  // handles pointers to them.
-  // FIXME: At some point we probably want to be importing incomplete types,
-  // so that pointers to different incomplete types themselves have distinct
-  // types. At that time it will be necessary to make the decision of whether
-  // or not to import an incomplete type declaration based on whether it's
-  // actually the struct backing a CF type:
-  //
-  //    typedef struct CGColor *CGColorRef;
-  //
-  // The best way to do this is probably to change CFDatabase.def to include
-  // struct names when relevant, not just pointer names. That way we can check
-  // both CFDatabase.def and the objc_bridge attribute and cover all our bases.
+  // Leave incomplete struct/enum/union types out of the table, unless they
+  // are types that will be imported as reference types (e.g., CF types or
+  // those that use SWIFT_SHARED_REFERENCE).
   if (auto *tagDecl = dyn_cast<clang::TagDecl>(named)) {
     // We add entries for ClassTemplateSpecializations that don't have
     // definition. It's possible that the decl will be instantiated by
@@ -2120,7 +1920,9 @@ void importer::addEntryToLookupTable(SwiftLookupTable &table,
     // ClassTemplateSPecializations here because we're currently writing the
     // AST, so we cannot modify it.
     if (!isa<clang::ClassTemplateSpecializationDecl>(named) &&
-        !tagDecl->getDefinition()) {
+        !tagDecl->getDefinition() &&
+        !(isa<clang::RecordDecl>(tagDecl) &&
+          hasImportAsRefAttr(cast<clang::RecordDecl>(tagDecl)))) {
       return;
     }
   }
@@ -2141,6 +1943,15 @@ void importer::addEntryToLookupTable(SwiftLookupTable &table,
                          named, importedName.getEffectiveContext());
         }
 
+        if (auto swiftNameAttr = named->getAttr<clang::SwiftNameAttr>()) {
+          auto parsedDeclName = parseDeclName(swiftNameAttr->getName());
+          auto swiftDeclName =
+              parsedDeclName.formDeclName(nameImporter.getContext());
+          if (importedName.getDeclName() != swiftDeclName)
+            table.addEntry(swiftDeclName, named,
+                           importedName.getEffectiveContext());
+        }
+
         return true;
       });
   if (failed) {
@@ -2232,16 +2043,6 @@ void importer::addEntryToLookupTable(SwiftLookupTable &table,
         addEntryToLookupTable(table, usingShadowDecl, nameImporter);
     }
   }
-
-  // If this decl represents an availability domain, add it to the lookup table
-  // as one.
-  // FIXME: [availability] Remove this once Clang has a lookup table.
-  if (auto varDecl = dyn_cast<clang::VarDecl>(named)) {
-    auto mutableVar = const_cast<clang::VarDecl *>(varDecl);
-    auto domainInfo = clangContext.getFeatureAvailInfo(mutableVar);
-    if (!domainInfo.first.empty())
-      table.addAvailabilityDomainDecl(domainInfo.first, mutableVar);
-  }
 }
 
 /// Returns the nearest parent of \p module that is marked \c explicit in its
@@ -2342,7 +2143,7 @@ void importer::finalizeLookupTable(
   if (table.resolveUnresolvedEntries(unresolved)) {
     // Complain about unresolved entries that remain.
     for (auto entry : unresolved) {
-      auto decl = entry.get<clang::NamedDecl *>();
+      auto *decl = cast<clang::NamedDecl *>(entry);
       auto swiftName = decl->getAttr<clang::SwiftNameAttr>();
 
       if (swiftName
diff --git a/lib/ClangImporter/SwiftLookupTable.h b/lib/ClangImporter/SwiftLookupTable.h
index 2886b716dab3a..5849233c110b6 100644
--- a/lib/ClangImporter/SwiftLookupTable.h
+++ b/lib/ClangImporter/SwiftLookupTable.h
@@ -486,10 +486,6 @@ class SwiftLookupTable {
   /// The list of Objective-C categories and extensions.
   llvm::SmallVector<clang::ObjCCategoryDecl *, 4> Categories;
 
-  /// A mapping from availability domain name strings to their corresponding
-  /// declarations.
-  llvm::SmallDenseMap<StringRef, clang::VarDecl *> AvailabilityDomains;
-
   /// A mapping from stored contexts to the set of global declarations that
   /// are mapped to members within that context.
   ///
@@ -554,9 +550,6 @@ class SwiftLookupTable {
   /// Add an Objective-C category or extension to the table.
   void addCategory(clang::ObjCCategoryDecl *category);
 
-  /// Add an entry for a Clang availability domain.
-  void addAvailabilityDomainDecl(StringRef name, clang::VarDecl *decl);
-
   /// Resolve any unresolved entries.
   ///
   /// \param unresolved Will be populated with the list of entries
@@ -600,7 +593,7 @@ class SwiftLookupTable {
 public:
   /// Lookup an unresolved context name and resolve it to a Clang
   /// named declaration.
-  clang::NamedDecl *resolveContext(StringRef unresolvedName);
+  const clang::NamedDecl *resolveContext(StringRef unresolvedName);
 
   /// Lookup the set of entities with the given base name.
   ///
@@ -639,10 +632,6 @@ class SwiftLookupTable {
   lookupGlobalsAsMembers(SerializedSwiftName baseName,
                          EffectiveClangContext searchContext);
 
-  /// Retrieve the `VarDecl` that represents the availability domain with the
-  /// given name, or `nullptr` if there isn't one.
-  clang::VarDecl *lookupAvailabilityDomainDecl(StringRef name);
-
   SmallVector<SingleEntry, 4>
   allGlobalsAsMembersInContext(EffectiveClangContext context);
 
diff --git a/lib/ConstExtract/ConstExtract.cpp b/lib/ConstExtract/ConstExtract.cpp
index 2cc24eb231011..98d3065bc1772 100644
--- a/lib/ConstExtract/ConstExtract.cpp
+++ b/lib/ConstExtract/ConstExtract.cpp
@@ -302,10 +302,8 @@ extractCompileTimeValue(Expr *expr, const DeclContext *declContext) {
 
     case ExprKind::Call: {
       auto callExpr = cast<CallExpr>(expr);
-      auto functionKind = callExpr->getFn()->getKind();
 
-      if (functionKind == ExprKind::DeclRef) {
-        auto declRefExpr = cast<DeclRefExpr>(callExpr->getFn());
+      if (auto declRefExpr = dyn_cast<DeclRefExpr>(callExpr->getFn())) {
         auto identifier =
             declRefExpr->getDecl()->getName().getBaseIdentifier().str().str();
 
@@ -314,17 +312,15 @@ extractCompileTimeValue(Expr *expr, const DeclContext *declContext) {
         return std::make_shared<FunctionCallValue>(identifier, parameters);
       }
 
-      if (functionKind == ExprKind::ConstructorRefCall) {
+      if (isa<ConstructorRefCallExpr>(callExpr->getFn())) {
         std::vector<FunctionParameter> parameters =
             extractFunctionArguments(callExpr->getArgs(), declContext);
         return std::make_shared<InitCallValue>(callExpr->getType(), parameters);
       }
 
-      if (functionKind == ExprKind::DotSyntaxCall) {
-        auto dotSyntaxCallExpr = cast<DotSyntaxCallExpr>(callExpr->getFn());
+      if (auto dotSyntaxCallExpr = dyn_cast<DotSyntaxCallExpr>(callExpr->getFn())) {
         auto fn = dotSyntaxCallExpr->getFn();
-        if (fn->getKind() == ExprKind::DeclRef) {
-          auto declRefExpr = cast<DeclRefExpr>(fn);
+        if (auto declRefExpr = dyn_cast<DeclRefExpr>(fn)) {
           auto baseIdentifierName =
               declRefExpr->getDecl()->getName().getBaseIdentifier().str().str();
 
@@ -355,14 +351,24 @@ extractCompileTimeValue(Expr *expr, const DeclContext *declContext) {
         }
       }
 
+      if (auto functionConversionExpr = dyn_cast<FunctionConversionExpr>(callExpr->getFn())) {
+        if (auto declRefExpr = dyn_cast<DeclRefExpr>(functionConversionExpr->getSubExpr())) {
+          auto identifier =
+              declRefExpr->getDecl()->getName().getBaseIdentifier().str().str();
+
+          std::vector<FunctionParameter> parameters =
+              extractFunctionArguments(callExpr->getArgs(), declContext);
+          return std::make_shared<FunctionCallValue>(identifier, parameters);
+        }
+      }
+
       break;
     }
 
     case ExprKind::DotSyntaxCall: {
       auto dotSyntaxCallExpr = cast<DotSyntaxCallExpr>(expr);
       auto fn = dotSyntaxCallExpr->getFn();
-      if (fn->getKind() == ExprKind::DeclRef) {
-        auto declRefExpr = cast<DeclRefExpr>(fn);
+      if (auto declRefExpr = dyn_cast<DeclRefExpr>(fn)) {
         auto caseName =
             declRefExpr->getDecl()->getName().getBaseIdentifier().str().str();
         return std::make_shared<EnumValue>(caseName, std::nullopt);
@@ -414,7 +420,7 @@ extractCompileTimeValue(Expr *expr, const DeclContext *declContext) {
       assert(!decl->hasDefaultExpr());
       switch (decl->getDefaultArgumentKind()) {
       case DefaultArgumentKind::NilLiteral:
-        return std::make_shared<RawLiteralValue>("nil");
+        return std::make_shared<NilLiteralValue>();
       case DefaultArgumentKind::EmptyArray:
         return std::make_shared<ArrayValue>(
             std::vector<std::shared_ptr<CompileTimeValue>>());
@@ -507,6 +513,12 @@ extractCompileTimeValue(Expr *expr, const DeclContext *declContext) {
       auto derivedExpr = cast<DerivedToBaseExpr>(expr);
       return extractCompileTimeValue(derivedExpr->getSubExpr(), declContext);
     }
+
+    case ExprKind::OpenExistential: {
+      auto openExistentialExpr = cast<OpenExistentialExpr>(expr);
+      return extractCompileTimeValue(openExistentialExpr->getExistentialValue(), declContext);
+    }
+
     default: {
       break;
     }
@@ -623,7 +635,7 @@ ConstValueTypeInfo ConstantValueInfoRequest::evaluate(
   auto shouldExtract = [&](DeclContext *decl) {
     if (auto SF = extractionScope.dyn_cast<const SourceFile *>())
       return decl->getOutermostParentSourceFile() == SF;
-    return decl->getParentModule() == extractionScope.get<ModuleDecl *>();
+    return decl->getParentModule() == cast<ModuleDecl *>(extractionScope);
   };
 
   std::vector<ConstValueTypePropertyInfo> Properties;
diff --git a/lib/Demangling/Context.cpp b/lib/Demangling/Context.cpp
index c762ea1930e18..c28d754bb641c 100644
--- a/lib/Demangling/Context.cpp
+++ b/lib/Demangling/Context.cpp
@@ -66,6 +66,12 @@ std::string Context::demangleSymbolAsString(llvm::StringRef MangledName,
   return demangling;
 }
 
+void Context::demangleSymbolAsString(llvm::StringRef MangledName,
+                                     NodePrinter &Printer) {
+  NodePointer root = demangleSymbolAsNode(MangledName);
+  nodeToString(root, Printer);
+}
+
 std::string Context::demangleTypeAsString(llvm::StringRef MangledName,
                                           const DemangleOptions &Options) {
   NodePointer root = demangleTypeAsNode(MangledName);
@@ -275,6 +281,11 @@ std::string demangleSymbolAsString(const char *MangledName,
                                     Options);
 }
 
+void demangleSymbolAsString(StringRef MangledName, NodePrinter &Printer) {
+  Context Ctx;
+  return Ctx.demangleSymbolAsString(MangledName, Printer);
+}
+
 std::string demangleTypeAsString(const char *MangledName,
                                  size_t MangledNameLength,
                                  const DemangleOptions &Options) {
diff --git a/lib/Demangling/Demangler.cpp b/lib/Demangling/Demangler.cpp
index df66c2672ffdc..062b0ee82bb75 100644
--- a/lib/Demangling/Demangler.cpp
+++ b/lib/Demangling/Demangler.cpp
@@ -601,6 +601,11 @@ NodePointer NodeFactory::createNode(Node::Kind K) {
 NodePointer NodeFactory::createNode(Node::Kind K, Node::IndexType Index) {
   return new (Allocate<Node>()) Node(K, Index);
 }
+NodePointer NodeFactory::createNode(Node::Kind K, uint64_t RemoteAddress,
+                                    uint8_t AddressSpace) {
+  return new (Allocate<Node>()) Node(K, RemoteAddress, AddressSpace);
+}
+
 NodePointer NodeFactory::createNodeWithAllocatedText(Node::Kind K,
                                                      llvm::StringRef Text) {
   return new (Allocate<Node>()) Node(K, Text);
@@ -1042,6 +1047,7 @@ NodePointer Demangler::demangleOperator() {
       case 'C': return demangleConcreteProtocolConformance();
       case 'D': return demangleDependentProtocolConformanceRoot();
       case 'I': return demangleDependentProtocolConformanceInherited();
+      case 'O': return demangleDependentProtocolConformanceOpaque();
       case 'P':
         return createWithChild(
             Node::Kind::ProtocolConformanceRefInTypeModule, popProtocol());
@@ -1119,7 +1125,8 @@ NodePointer Demangler::demangleOperator() {
       // outlined copy functions. We treat such a suffix as "unmangled suffix".
       pushBack();
       return createNode(Node::Kind::Suffix, consumeAll());
-    case '$': return demangleIntegerType();
+    case '$':
+      return demangleIntegerType();
     default:
       pushBack();
       return demangleIdentifier();
@@ -1961,6 +1968,7 @@ NodePointer Demangler::popAnyProtocolConformance() {
     case Node::Kind::DependentProtocolConformanceRoot:
     case Node::Kind::DependentProtocolConformanceInherited:
     case Node::Kind::DependentProtocolConformanceAssociated:
+    case Node::Kind::DependentProtocolConformanceOpaque:
       return true;
 
     default:
@@ -2060,6 +2068,13 @@ NodePointer Demangler::demangleDependentConformanceIndex() {
   return createNode(Node::Kind::Index, unsigned(index) - 2);
 }
 
+NodePointer Demangler::demangleDependentProtocolConformanceOpaque() {
+  NodePointer type = popNode(Node::Kind::Type);
+  NodePointer conformance = popDependentProtocolConformance();
+  return createWithChildren(Node::Kind::DependentProtocolConformanceOpaque,
+                            conformance, type);
+}
+
 NodePointer Demangler::demangleRetroactiveConformance() {
   NodePointer index = demangleIndexAsNode();
   NodePointer conformance = popAnyProtocolConformance();
@@ -2126,6 +2141,7 @@ bool Demangle::nodeConsumesGenericArgs(Node *node) {
     case Node::Kind::DefaultArgumentInitializer:
     case Node::Kind::Initializer:
     case Node::Kind::PropertyWrapperBackingInitializer:
+    case Node::Kind::PropertyWrappedFieldInitAccessor:
     case Node::Kind::PropertyWrapperInitFromProjectedValue:
     case Node::Kind::Static:
       return false;
@@ -2292,6 +2308,22 @@ NodePointer Demangler::demangleImplParameterSending() {
   return createNode(Node::Kind::ImplParameterSending, attr);
 }
 
+NodePointer Demangler::demangleImplParameterIsolated() {
+  // Empty string represents default differentiability.
+  if (!nextIf('I'))
+    return nullptr;
+  const char *attr = "isolated";
+  return createNode(Node::Kind::ImplParameterIsolated, attr);
+}
+
+NodePointer Demangler::demangleImplParameterImplicitLeading() {
+  // Empty string represents default differentiability.
+  if (!nextIf('L'))
+    return nullptr;
+  const char *attr = "sil_implicit_leading_param";
+  return createNode(Node::Kind::ImplParameterImplicitLeading, attr);
+}
+
 NodePointer Demangler::demangleImplParameterResultDifferentiability() {
   // Empty string represents default differentiability.
   const char *attr = "";
@@ -2443,6 +2475,10 @@ NodePointer Demangler::demangleImplFunctionType() {
       Param = addChild(Param, Diff);
     if (auto Sending = demangleImplParameterSending())
       Param = addChild(Param, Sending);
+    if (auto Sending = demangleImplParameterIsolated())
+      Param = addChild(Param, Sending);
+    if (auto Sending = demangleImplParameterImplicitLeading())
+      Param = addChild(Param, Sending);
     ++NumTypesToAdd;
   }
 
@@ -3343,43 +3379,40 @@ NodePointer Demangler::demangleFunctionSpecialization() {
     if (Param->getKind() != Node::Kind::FunctionSignatureSpecializationParam)
       continue;
 
-    if (Param->getNumChildren() == 0)
-      continue;
-    NodePointer KindNd = Param->getFirstChild();
-    assert(KindNd->getKind() ==
-             Node::Kind::FunctionSignatureSpecializationParamKind);
-    auto ParamKind = (FunctionSigSpecializationParamKind)KindNd->getIndex();
-    switch (ParamKind) {
-      case FunctionSigSpecializationParamKind::ConstantPropFunction:
-      case FunctionSigSpecializationParamKind::ConstantPropGlobal:
-      case FunctionSigSpecializationParamKind::ConstantPropString:
-      case FunctionSigSpecializationParamKind::ConstantPropKeyPath:
-      case FunctionSigSpecializationParamKind::ClosureProp: {
-        size_t FixedChildren = Param->getNumChildren();
-        while (NodePointer Ty = popNode(Node::Kind::Type)) {
-          if (ParamKind != FunctionSigSpecializationParamKind::ClosureProp &&
-              ParamKind != FunctionSigSpecializationParamKind::ConstantPropKeyPath)
-            return nullptr;
-          Param = addChild(Param, Ty);
-        }
-        NodePointer Name = popNode(Node::Kind::Identifier);
-        if (!Name)
-          return nullptr;
-        StringRef Text = Name->getText();
-        if (ParamKind ==
-                FunctionSigSpecializationParamKind::ConstantPropString &&
-            !Text.empty() && Text[0] == '_') {
-          // A '_' escapes a leading digit or '_' of a string constant.
-          Text = Text.drop_front(1);
+    size_t fixedChildren = Param->getNumChildren();
+    NodePointer paramToAdd = Param;
+    for (size_t childIdx = 0; childIdx < fixedChildren; ++childIdx) {
+      NodePointer KindNd = Param->getChild(fixedChildren - childIdx - 1);
+      if (KindNd->getKind() != Node::Kind::FunctionSignatureSpecializationParamKind)
+        continue;
+
+      auto ParamKind = (FunctionSigSpecializationParamKind)KindNd->getIndex();
+      switch (ParamKind) {
+        case FunctionSigSpecializationParamKind::ClosureProp: {
+          while (NodePointer Ty = popNode(Node::Kind::Type)) {
+            paramToAdd = addChild(paramToAdd, Ty);
+          }
+          break;
         }
-        addChild(Param, createNodeWithAllocatedText(
-          Node::Kind::FunctionSignatureSpecializationParamPayload, Text));
-        Param->reverseChildren(FixedChildren);
-        break;
+        case FunctionSigSpecializationParamKind::ConstantPropKeyPath:
+          paramToAdd = addChild(paramToAdd, popNode(Node::Kind::Type));
+          paramToAdd = addChild(paramToAdd, popNode(Node::Kind::Type));
+          break;
+        case FunctionSigSpecializationParamKind::ConstantPropStruct:
+          paramToAdd = addChild(paramToAdd, popNode(Node::Kind::Type));
+          continue;
+        case FunctionSigSpecializationParamKind::ConstantPropFunction:
+        case FunctionSigSpecializationParamKind::ConstantPropGlobal:
+        case FunctionSigSpecializationParamKind::ConstantPropString:
+          break;
+        default:
+          continue;
       }
-      default:
-        break;
+      paramToAdd = addChild(paramToAdd, popNode(Node::Kind::Identifier));
     }
+    if (!paramToAdd)
+      return nullptr;
+    Param->reverseChildren(fixedChildren);
   }
   return Spec;
 }
@@ -3397,59 +3430,92 @@ NodePointer Demangler::demangleFuncSpecParam(Node::Kind Kind) {
       return addChild(Param, createNode(
         Node::Kind::FunctionSignatureSpecializationParamKind,
         uint64_t(FunctionSigSpecializationParamKind::ClosureProp)));
+    case 'C': {
+      // Consumes an identifier and multiple type parameters.
+      // The parameters will be added later.
+      addChild(Param, createNode(
+        Node::Kind::FunctionSignatureSpecializationParamKind,
+        uint64_t(FunctionSigSpecializationParamKind::ClosurePropPreviousArg)));
+      int prevArgIdx = demangleNatural();
+      if (prevArgIdx < 0)
+        return nullptr;
+      return addChild(Param, createNode(
+         Node::Kind::FunctionSignatureSpecializationParamPayload, (Node::IndexType)prevArgIdx));
+    }
     case 'p': {
-      switch (nextChar()) {
-        case 'f':
-          // Consumes an identifier parameter, which will be added later.
-          return addChild(
-              Param,
-              createNode(Node::Kind::FunctionSignatureSpecializationParamKind,
-                         Node::IndexType(FunctionSigSpecializationParamKind::
-                                             ConstantPropFunction)));
-        case 'g':
-          // Consumes an identifier parameter, which will be added later.
-          return addChild(
-              Param,
-              createNode(
-                  Node::Kind::FunctionSignatureSpecializationParamKind,
-                  Node::IndexType(
-                      FunctionSigSpecializationParamKind::ConstantPropGlobal)));
-        case 'i':
-          return addFuncSpecParamNumber(Param,
-                    FunctionSigSpecializationParamKind::ConstantPropInteger);
-        case 'd':
-          return addFuncSpecParamNumber(Param,
-                      FunctionSigSpecializationParamKind::ConstantPropFloat);
-        case 's': {
-          // Consumes an identifier parameter (the string constant),
-          // which will be added later.
-          const char *Encoding = nullptr;
-          switch (nextChar()) {
-            case 'b': Encoding = "u8"; break;
-            case 'w': Encoding = "u16"; break;
-            case 'c': Encoding = "objc"; break;
-            default: return nullptr;
+      for (;;) {
+        switch (nextChar()) {
+          case 'S':
+            // Consumes an identifier parameter, which will be added later.
+            addChild(
+                Param,
+                createNode(Node::Kind::FunctionSignatureSpecializationParamKind,
+                           Node::IndexType(FunctionSigSpecializationParamKind::
+                                               ConstantPropStruct)));
+            break;
+          case 'f':
+            // Consumes an identifier parameter, which will be added later.
+            addChild(
+                Param,
+                createNode(Node::Kind::FunctionSignatureSpecializationParamKind,
+                           Node::IndexType(FunctionSigSpecializationParamKind::
+                                               ConstantPropFunction)));
+            break;
+          case 'g':
+            // Consumes an identifier parameter, which will be added later.
+            addChild(
+                Param,
+                createNode(
+                    Node::Kind::FunctionSignatureSpecializationParamKind,
+                    Node::IndexType(
+                        FunctionSigSpecializationParamKind::ConstantPropGlobal)));
+            break;
+          case 'i':
+            if (!addFuncSpecParamNumber(Param,
+                      FunctionSigSpecializationParamKind::ConstantPropInteger)) {
+              return nullptr;
+            }
+            break;
+          case 'd':
+            if (!addFuncSpecParamNumber(Param,
+                        FunctionSigSpecializationParamKind::ConstantPropFloat)) {
+              return nullptr;
+            }
+            break;
+          case 's': {
+            // Consumes an identifier parameter (the string constant),
+            // which will be added later.
+            const char *Encoding = nullptr;
+            switch (nextChar()) {
+              case 'b': Encoding = "u8"; break;
+              case 'w': Encoding = "u16"; break;
+              case 'c': Encoding = "objc"; break;
+              default: return nullptr;
+            }
+            addChild(Param,
+                     createNode(
+                         Node::Kind::FunctionSignatureSpecializationParamKind,
+                         Node::IndexType(
+                             swift::Demangle::FunctionSigSpecializationParamKind::
+                                 ConstantPropString)));
+            addChild(Param, createNode(
+                    Node::Kind::FunctionSignatureSpecializationParamPayload,
+                    Encoding));
+            break;
           }
-          addChild(Param,
-                   createNode(
-                       Node::Kind::FunctionSignatureSpecializationParamKind,
-                       Node::IndexType(
-                           swift::Demangle::FunctionSigSpecializationParamKind::
-                               ConstantPropString)));
-          return addChild(Param, createNode(
-                  Node::Kind::FunctionSignatureSpecializationParamPayload,
-                  Encoding));
-        }
-        case 'k': {
-          // Consumes two types and a SHA1 identifier.
-          return addChild(
-              Param,
-              createNode(Node::Kind::FunctionSignatureSpecializationParamKind,
-                         Node::IndexType(FunctionSigSpecializationParamKind::
-                                             ConstantPropKeyPath)));
+          case 'k': {
+            // Consumes two types and a SHA1 identifier.
+            addChild(
+                Param,
+                createNode(Node::Kind::FunctionSignatureSpecializationParamKind,
+                           Node::IndexType(FunctionSigSpecializationParamKind::
+                                               ConstantPropKeyPath)));
+            break;
+          }
+          default:
+            pushBack();
+            return Param;
         }
-        default:
-          return nullptr;
       }
     }
     case 'e': {
@@ -3637,6 +3703,15 @@ NodePointer Demangler::demangleWitness() {
     }
     case 'O': {
       switch (nextChar()) {
+      case 'B': {
+        if (auto sig = popNode(Node::Kind::DependentGenericSignature))
+          return createWithChildren(
+              Node::Kind::OutlinedInitializeWithTakeNoValueWitness,
+              popNode(Node::Kind::Type), sig);
+        return createWithChild(
+            Node::Kind::OutlinedInitializeWithTakeNoValueWitness,
+            popNode(Node::Kind::Type));
+      }
       case 'C': {
         if (auto sig = popNode(Node::Kind::DependentGenericSignature))
           return createWithChildren(Node::Kind::OutlinedInitializeWithCopyNoValueWitness,
@@ -4032,6 +4107,12 @@ NodePointer Demangler::demangleAccessor(NodePointer ChildNode) {
     case 'M': Kind = Node::Kind::ModifyAccessor; break;
     case 'x': Kind = Node::Kind::Modify2Accessor; break;
     case 'i': Kind = Node::Kind::InitAccessor; break;
+    case 'b':
+      Kind = Node::Kind::BorrowAccessor;
+      break;
+    case 'z':
+      Kind = Node::Kind::MutateAccessor;
+      break;
     case 'a':
       switch (nextChar()) {
         case 'O': Kind = Node::Kind::OwningMutableAddressor; break;
@@ -4092,6 +4173,10 @@ NodePointer Demangler::demangleFunctionEntity() {
       Args = None;
       Kind = Node::Kind::PropertyWrapperBackingInitializer;
       break;
+    case 'F':
+      Args = None;
+      Kind = Node::Kind::PropertyWrappedFieldInitAccessor;
+      break;
     case 'W':
       Args = None;
       Kind = Node::Kind::PropertyWrapperInitFromProjectedValue;
diff --git a/lib/Demangling/NodePrinter.cpp b/lib/Demangling/NodePrinter.cpp
index 4f7cbbf24470e..6762fadefa8a6 100644
--- a/lib/Demangling/NodePrinter.cpp
+++ b/lib/Demangling/NodePrinter.cpp
@@ -166,393 +166,351 @@ static StringRef toString(ValueWitnessKind k) {
   }
   printer_unreachable("bad value witness kind");
 }
+} // end anonymous namespace
 
-class NodePrinter {
-private:
-  DemanglerPrinter Printer;
-  DemangleOptions Options;
-  bool SpecializationPrefixPrinted = false;
-  bool isValid = true;
-
-public:
-  NodePrinter(DemangleOptions options) : Options(options) {}
-
-  std::string printRoot(NodePointer root) {
-    isValid = true;
-    print(root, 0);
-    if (isValid)
-      return std::move(Printer).str();
-    return "";
+void NodePrinter::printChildren(Node::iterator begin, Node::iterator end,
+                                unsigned depth, const char *sep) {
+  for (; begin != end;) {
+    print(*begin, depth + 1);
+    ++begin;
+    if (sep && begin != end)
+      Printer << sep;
   }
+}
 
-private:
-  static const unsigned MaxDepth = 768;
-
-  /// Called when the node tree in valid.
-  ///
-  /// The demangler already catches most error cases and mostly produces valid
-  /// node trees. But some cases are difficult to catch in the demangler and
-  /// instead the NodePrinter bails.
-  void setInvalid() { isValid = false; }
+void NodePrinter::printChildren(NodePointer Node, unsigned depth,
+                                const char *sep) {
+  if (!Node)
+    return;
+  Node::iterator begin = Node->begin(), end = Node->end();
+  printChildren(begin, end, depth, sep);
+}
 
-  void printChildren(Node::iterator begin, Node::iterator end, unsigned depth,
-                     const char *sep = nullptr) {
-    for (; begin != end;) {
-      print(*begin, depth + 1);
-      ++begin;
-      if (sep && begin != end)
-        Printer << sep;
-    }
+NodePointer NodePrinter::getFirstChildOfKind(NodePointer Node,
+                                             Node::Kind kind) {
+  if (!Node)
+    return nullptr;
+  for (NodePointer child : *Node) {
+    if (child && child->getKind() == kind)
+      return child;
   }
+  return nullptr;
+}
 
-  void printChildren(NodePointer Node, unsigned depth,
-                     const char *sep = nullptr) {
-    if (!Node)
-      return;
-    Node::iterator begin = Node->begin(), end = Node->end();
-    printChildren(begin, end, depth, sep);
-  }
+void NodePrinter::printBoundGenericNoSugar(NodePointer Node, unsigned depth) {
+  if (Node->getNumChildren() < 2)
+    return;
+  NodePointer typelist = Node->getChild(1);
+  print(Node->getChild(0), depth + 1);
+  Printer << "<";
+  printChildren(typelist, depth, ", ");
+  Printer << ">";
+}
 
-  NodePointer getFirstChildOfKind(NodePointer Node, Node::Kind kind) {
-    if (!Node)
-      return nullptr;
-    for (NodePointer child : *Node) {
-      if (child && child->getKind() == kind)
-        return child;
-    }
-    return nullptr;
-  }
+static bool isExistentialType(NodePointer node) {
+  return (node->getKind() == Node::Kind::ExistentialMetatype ||
+          node->getKind() == Node::Kind::ProtocolList ||
+          node->getKind() == Node::Kind::ProtocolListWithClass ||
+          node->getKind() == Node::Kind::ProtocolListWithAnyObject);
+}
 
-  void printBoundGenericNoSugar(NodePointer Node, unsigned depth) {
-    if (Node->getNumChildren() < 2)
-      return;
-    NodePointer typelist = Node->getChild(1);
-    print(Node->getChild(0), depth + 1);
-    Printer << "<";
-    printChildren(typelist, depth, ", ");
-    Printer << ">";
-  }
+void NodePrinter::printOptionalIndex(NodePointer node) {
+  assert(node->getKind() == Node::Kind::Index ||
+         node->getKind() == Node::Kind::UnknownIndex);
+  if (node->hasIndex())
+    Printer << "#" << node->getIndex() << " ";
+}
 
-  void printOptionalIndex(NodePointer node) {
-    assert(node->getKind() == Node::Kind::Index ||
-           node->getKind() == Node::Kind::UnknownIndex);
-    if (node->hasIndex())
-      Printer << "#" << node->getIndex() << " ";
-  }
+bool NodePrinter::printContext(NodePointer Context) {
+  if (!Options.QualifyEntities)
+    return false;
 
-  static bool isSwiftModule(NodePointer node) {
-    return (node->getKind() == Node::Kind::Module &&
-            node->getText() == STDLIB_NAME);
-  }
-  
-  bool printContext(NodePointer Context) {
-    if (!Options.QualifyEntities)
+  if (Context->getKind() == Node::Kind::Module) {
+    if (Context->getText() == swift::STDLIB_NAME)
+      return Options.DisplayStdlibModule;
+    if (Context->getText() == swift::MANGLING_MODULE_OBJC)
+      return Options.DisplayObjCModule;
+    if (Context->getText() == Options.HidingCurrentModule)
       return false;
+    if (Context->getText().starts_with(LLDB_EXPRESSIONS_MODULE_NAME_PREFIX))
+      return Options.DisplayDebuggerGeneratedModule;
+  }
+  return true;
+}
 
-    if (Context->getKind() == Node::Kind::Module) {
-      if (Context->getText() == swift::STDLIB_NAME)
-        return Options.DisplayStdlibModule;
-      if (Context->getText() == swift::MANGLING_MODULE_OBJC)
-        return Options.DisplayObjCModule;
-      if (Context->getText() == Options.HidingCurrentModule)
-        return false;
-      if (Context->getText().starts_with(LLDB_EXPRESSIONS_MODULE_NAME_PREFIX))
-        return Options.DisplayDebuggerGeneratedModule;
-    }
+bool NodePrinter::isSimpleType(NodePointer Node) {
+  switch (Node->getKind()) {
+  case Node::Kind::AssociatedType:
+  case Node::Kind::AssociatedTypeRef:
+  case Node::Kind::BoundGenericClass:
+  case Node::Kind::BoundGenericEnum:
+  case Node::Kind::BoundGenericStructure:
+  case Node::Kind::BoundGenericProtocol:
+  case Node::Kind::BoundGenericOtherNominalType:
+  case Node::Kind::BoundGenericTypeAlias:
+  case Node::Kind::BoundGenericFunction:
+  case Node::Kind::BuiltinTypeName:
+  case Node::Kind::BuiltinTupleType:
+  case Node::Kind::BuiltinFixedArray:
+  case Node::Kind::Class:
+  case Node::Kind::DependentGenericType:
+  case Node::Kind::DependentMemberType:
+  case Node::Kind::DependentGenericParamType:
+  case Node::Kind::DynamicSelf:
+  case Node::Kind::Enum:
+  case Node::Kind::ErrorType:
+  case Node::Kind::ExistentialMetatype:
+  case Node::Kind::Metatype:
+  case Node::Kind::MetatypeRepresentation:
+  case Node::Kind::Module:
+  case Node::Kind::Tuple:
+  case Node::Kind::Pack:
+  case Node::Kind::SILPackDirect:
+  case Node::Kind::SILPackIndirect:
+  case Node::Kind::ConstrainedExistentialRequirementList:
+  case Node::Kind::ConstrainedExistentialSelf:
+  case Node::Kind::Protocol:
+  case Node::Kind::ProtocolSymbolicReference:
+  case Node::Kind::ReturnType:
+  case Node::Kind::SILBoxType:
+  case Node::Kind::SILBoxTypeWithLayout:
+  case Node::Kind::Structure:
+  case Node::Kind::OtherNominalType:
+  case Node::Kind::TupleElementName:
+  case Node::Kind::TypeAlias:
+  case Node::Kind::TypeList:
+  case Node::Kind::LabelList:
+  case Node::Kind::TypeSymbolicReference:
+  case Node::Kind::SugaredOptional:
+  case Node::Kind::SugaredArray:
+  case Node::Kind::SugaredInlineArray:
+  case Node::Kind::SugaredDictionary:
+  case Node::Kind::SugaredParen:
+  case Node::Kind::Integer:
+  case Node::Kind::NegativeInteger:
     return true;
-  }
 
-  static bool isIdentifier(NodePointer node, StringRef desired) {
-    return (node->getKind() == Node::Kind::Identifier &&
-            node->getText() == desired);
-  }
-  
-  enum class SugarType {
-    None,
-    Optional,
-    ImplicitlyUnwrappedOptional,
-    Array,
-    Dictionary
-  };
+  case Node::Kind::Type:
+    return isSimpleType(Node->getChild(0));
 
-  enum class TypePrinting {
-    NoType,
-    WithColon,
-    FunctionStyle
-  };
+  case Node::Kind::ProtocolList:
+    return Node->getChild(0)->getNumChildren() <= 1;
 
-  /// Determine whether this is a "simple" type, from the type-simple
-  /// production.
-  bool isSimpleType(NodePointer Node) {
-    switch (Node->getKind()) {
-    case Node::Kind::AssociatedType:
-    case Node::Kind::AssociatedTypeRef:
-    case Node::Kind::BoundGenericClass:
-    case Node::Kind::BoundGenericEnum:
-    case Node::Kind::BoundGenericStructure:
-    case Node::Kind::BoundGenericProtocol:
-    case Node::Kind::BoundGenericOtherNominalType:
-    case Node::Kind::BoundGenericTypeAlias:
-    case Node::Kind::BoundGenericFunction:
-    case Node::Kind::BuiltinTypeName:
-    case Node::Kind::BuiltinTupleType:
-    case Node::Kind::BuiltinFixedArray:
-    case Node::Kind::Class:
-    case Node::Kind::DependentGenericType:
-    case Node::Kind::DependentMemberType:
-    case Node::Kind::DependentGenericParamType:
-    case Node::Kind::DynamicSelf:
-    case Node::Kind::Enum:
-    case Node::Kind::ErrorType:
-    case Node::Kind::ExistentialMetatype:
-    case Node::Kind::Metatype:
-    case Node::Kind::MetatypeRepresentation:
-    case Node::Kind::Module:
-    case Node::Kind::Tuple:
-    case Node::Kind::Pack:
-    case Node::Kind::SILPackDirect:
-    case Node::Kind::SILPackIndirect:
-    case Node::Kind::ConstrainedExistentialRequirementList:
-    case Node::Kind::ConstrainedExistentialSelf:
-    case Node::Kind::Protocol:
-    case Node::Kind::ProtocolSymbolicReference:
-    case Node::Kind::ReturnType:
-    case Node::Kind::SILBoxType:
-    case Node::Kind::SILBoxTypeWithLayout:
-    case Node::Kind::Structure:
-    case Node::Kind::OtherNominalType:
-    case Node::Kind::TupleElementName:
-    case Node::Kind::TypeAlias:
-    case Node::Kind::TypeList:
-    case Node::Kind::LabelList:
-    case Node::Kind::TypeSymbolicReference:
-    case Node::Kind::SugaredOptional:
-    case Node::Kind::SugaredArray:
-    case Node::Kind::SugaredInlineArray:
-    case Node::Kind::SugaredDictionary:
-    case Node::Kind::SugaredParen:
-    case Node::Kind::Integer:
-    case Node::Kind::NegativeInteger:
-      return true;
+  case Node::Kind::ProtocolListWithAnyObject:
+    return Node->getChild(0)->getChild(0)->getNumChildren() == 0;
 
-    case Node::Kind::Type:
-      return isSimpleType(Node->getChild(0));
-
-    case Node::Kind::ProtocolList:
-      return Node->getChild(0)->getNumChildren() <= 1;
-
-    case Node::Kind::ProtocolListWithAnyObject:
-      return Node->getChild(0)->getChild(0)->getNumChildren() == 0;
-
-    case Node::Kind::ConstrainedExistential:
-    case Node::Kind::PackElement:
-    case Node::Kind::PackElementLevel:
-    case Node::Kind::PackExpansion:
-    case Node::Kind::ProtocolListWithClass:
-    case Node::Kind::AccessorAttachedMacroExpansion:
-    case Node::Kind::AccessorFunctionReference:
-    case Node::Kind::Allocator:
-    case Node::Kind::ArgumentTuple:
-    case Node::Kind::AssociatedConformanceDescriptor:
-    case Node::Kind::AssociatedTypeDescriptor:
-    case Node::Kind::AssociatedTypeMetadataAccessor:
-    case Node::Kind::AssociatedTypeWitnessTableAccessor:
-    case Node::Kind::AsyncRemoved:
-    case Node::Kind::AutoClosureType:
-    case Node::Kind::BaseConformanceDescriptor:
-    case Node::Kind::BaseWitnessTableAccessor:
-    case Node::Kind::BodyAttachedMacroExpansion:
-    case Node::Kind::ClangType:
-    case Node::Kind::ClassMetadataBaseOffset:
-    case Node::Kind::CFunctionPointer:
-    case Node::Kind::ConformanceAttachedMacroExpansion:
-    case Node::Kind::Constructor:
-    case Node::Kind::CoroutineContinuationPrototype:
-    case Node::Kind::CurryThunk:
-    case Node::Kind::SILThunkIdentity:
-    case Node::Kind::DispatchThunk:
-    case Node::Kind::Deallocator:
-    case Node::Kind::IsolatedDeallocator:
-    case Node::Kind::DeclContext:
-    case Node::Kind::DefaultArgumentInitializer:
-    case Node::Kind::DefaultAssociatedTypeMetadataAccessor:
-    case Node::Kind::DefaultAssociatedConformanceAccessor:
-    case Node::Kind::DependentAssociatedTypeRef:
-    case Node::Kind::DependentGenericSignature:
-    case Node::Kind::DependentGenericParamPackMarker:
-    case Node::Kind::DependentGenericParamCount:
-    case Node::Kind::DependentGenericConformanceRequirement:
-    case Node::Kind::DependentGenericLayoutRequirement:
-    case Node::Kind::DependentGenericSameTypeRequirement:
-    case Node::Kind::DependentGenericSameShapeRequirement:
-    case Node::Kind::DependentPseudogenericSignature:
-    case Node::Kind::Destructor:
-    case Node::Kind::DidSet:
-    case Node::Kind::DirectMethodReferenceAttribute:
-    case Node::Kind::Directness:
-    case Node::Kind::DynamicAttribute:
-    case Node::Kind::EscapingAutoClosureType:
-    case Node::Kind::EscapingObjCBlock:
-    case Node::Kind::NoEscapeFunctionType:
-    case Node::Kind::ExplicitClosure:
-    case Node::Kind::Extension:
-    case Node::Kind::ExtensionAttachedMacroExpansion:
-    case Node::Kind::EnumCase:
-    case Node::Kind::FieldOffset:
-    case Node::Kind::FreestandingMacroExpansion:
-    case Node::Kind::FullObjCResilientClassStub:
-    case Node::Kind::FullTypeMetadata:
-    case Node::Kind::Function:
-    case Node::Kind::FunctionSignatureSpecialization:
-    case Node::Kind::FunctionSignatureSpecializationParam:
-    case Node::Kind::FunctionSignatureSpecializationReturn:
-    case Node::Kind::FunctionSignatureSpecializationParamKind:
-    case Node::Kind::FunctionSignatureSpecializationParamPayload:
-    case Node::Kind::FunctionType:
-    case Node::Kind::GenericProtocolWitnessTable:
-    case Node::Kind::GenericProtocolWitnessTableInstantiationFunction:
-    case Node::Kind::GenericPartialSpecialization:
-    case Node::Kind::GenericPartialSpecializationNotReAbstracted:
-    case Node::Kind::GenericSpecialization:
-    case Node::Kind::GenericSpecializationNotReAbstracted:
-    case Node::Kind::GenericSpecializationInResilienceDomain:
-    case Node::Kind::GenericSpecializationParam:
-    case Node::Kind::GenericSpecializationPrespecialized:
-    case Node::Kind::InlinedGenericFunction:
-    case Node::Kind::GenericTypeMetadataPattern:
-    case Node::Kind::Getter:
-    case Node::Kind::Global:
-    case Node::Kind::GlobalGetter:
-    case Node::Kind::Identifier:
-    case Node::Kind::Index:
-    case Node::Kind::InitAccessor:
-    case Node::Kind::IVarInitializer:
-    case Node::Kind::IVarDestroyer:
-    case Node::Kind::ImplDifferentiabilityKind:
-    case Node::Kind::ImplEscaping:
-    case Node::Kind::ImplErasedIsolation:
-    case Node::Kind::ImplSendingResult:
-    case Node::Kind::ImplConvention:
-    case Node::Kind::ImplParameterResultDifferentiability:
-    case Node::Kind::ImplParameterSending:
-    case Node::Kind::ImplFunctionAttribute:
-    case Node::Kind::ImplFunctionConvention:
-    case Node::Kind::ImplFunctionConventionName:
-    case Node::Kind::ImplFunctionType:
-    case Node::Kind::ImplCoroutineKind:
-    case Node::Kind::ImplInvocationSubstitutions:
-    case Node::Kind::ImplPatternSubstitutions:
-    case Node::Kind::ImplicitClosure:
-    case Node::Kind::ImplParameter:
-    case Node::Kind::ImplResult:
-    case Node::Kind::ImplYield:
-    case Node::Kind::ImplErrorResult:
-    case Node::Kind::InOut:
-    case Node::Kind::InfixOperator:
-    case Node::Kind::Initializer:
-    case Node::Kind::Isolated:
-    case Node::Kind::Sending:
-    case Node::Kind::CompileTimeLiteral:
-    case Node::Kind::ConstValue:
-    case Node::Kind::PropertyWrapperBackingInitializer:
-    case Node::Kind::PropertyWrapperInitFromProjectedValue:
-    case Node::Kind::KeyPathGetterThunkHelper:
-    case Node::Kind::KeyPathSetterThunkHelper:
-    case Node::Kind::KeyPathUnappliedMethodThunkHelper:
-    case Node::Kind::KeyPathAppliedMethodThunkHelper:
-    case Node::Kind::KeyPathEqualsThunkHelper:
-    case Node::Kind::KeyPathHashThunkHelper:
-    case Node::Kind::LazyProtocolWitnessTableAccessor:
-    case Node::Kind::LazyProtocolWitnessTableCacheVariable:
-    case Node::Kind::LocalDeclName:
-    case Node::Kind::Macro:
-    case Node::Kind::MacroExpansionLoc:
-    case Node::Kind::MacroExpansionUniqueName:
-    case Node::Kind::MaterializeForSet:
-    case Node::Kind::MemberAttributeAttachedMacroExpansion:
-    case Node::Kind::MemberAttachedMacroExpansion:
-    case Node::Kind::MergedFunction:
-    case Node::Kind::Metaclass:
-    case Node::Kind::MethodDescriptor:
-    case Node::Kind::MethodLookupFunction:
-    case Node::Kind::ModifyAccessor:
-    case Node::Kind::Modify2Accessor:
-    case Node::Kind::NativeOwningAddressor:
-    case Node::Kind::NativeOwningMutableAddressor:
-    case Node::Kind::NativePinningAddressor:
-    case Node::Kind::NativePinningMutableAddressor:
-    case Node::Kind::NominalTypeDescriptor:
-    case Node::Kind::NominalTypeDescriptorRecord:
-    case Node::Kind::NonObjCAttribute:
-    case Node::Kind::Number:
-    case Node::Kind::ObjCAsyncCompletionHandlerImpl:
-    case Node::Kind::ObjCAttribute:
-    case Node::Kind::ObjCBlock:
-    case Node::Kind::ObjCMetadataUpdateFunction:
-    case Node::Kind::ObjCResilientClassStub:
-    case Node::Kind::OpaqueTypeDescriptor:
-    case Node::Kind::OpaqueTypeDescriptorRecord:
-    case Node::Kind::OpaqueTypeDescriptorAccessor:
-    case Node::Kind::OpaqueTypeDescriptorAccessorImpl:
-    case Node::Kind::OpaqueTypeDescriptorAccessorKey:
-    case Node::Kind::OpaqueTypeDescriptorAccessorVar:
-    case Node::Kind::Owned:
-    case Node::Kind::OwningAddressor:
-    case Node::Kind::OwningMutableAddressor:
-    case Node::Kind::PartialApplyForwarder:
-    case Node::Kind::PartialApplyObjCForwarder:
-    case Node::Kind::PeerAttachedMacroExpansion:
-    case Node::Kind::PostfixOperator:
-    case Node::Kind::PreambleAttachedMacroExpansion:
-    case Node::Kind::PredefinedObjCAsyncCompletionHandlerImpl:
-    case Node::Kind::PrefixOperator:
-    case Node::Kind::PrivateDeclName:
-    case Node::Kind::PropertyDescriptor:
-    case Node::Kind::ProtocolConformance:
-    case Node::Kind::ProtocolConformanceDescriptor:
-    case Node::Kind::ProtocolConformanceDescriptorRecord:
-    case Node::Kind::MetadataInstantiationCache:
-    case Node::Kind::ProtocolDescriptor:
-    case Node::Kind::ProtocolDescriptorRecord:
-    case Node::Kind::ProtocolRequirementsBaseDescriptor:
-    case Node::Kind::ProtocolSelfConformanceDescriptor:
-    case Node::Kind::ProtocolSelfConformanceWitness:
-    case Node::Kind::ProtocolSelfConformanceWitnessTable:
-    case Node::Kind::ProtocolWitness:
-    case Node::Kind::ProtocolWitnessTable:
-    case Node::Kind::ProtocolWitnessTableAccessor:
-    case Node::Kind::ProtocolWitnessTablePattern:
-    case Node::Kind::ReabstractionThunk:
-    case Node::Kind::ReabstractionThunkHelper:
-    case Node::Kind::ReabstractionThunkHelperWithSelf:
-    case Node::Kind::ReabstractionThunkHelperWithGlobalActor:
-    case Node::Kind::ReadAccessor:
-    case Node::Kind::Read2Accessor:
-    case Node::Kind::RelatedEntityDeclName:
-    case Node::Kind::RetroactiveConformance:
-    case Node::Kind::Setter:
-    case Node::Kind::Shared:
-    case Node::Kind::SILBoxLayout:
-    case Node::Kind::SILBoxMutableField:
-    case Node::Kind::SILBoxImmutableField:
-    case Node::Kind::IsSerialized:
-    case Node::Kind::DroppedArgument:
-    case Node::Kind::SpecializationPassID:
-    case Node::Kind::Static:
-    case Node::Kind::Subscript:
-    case Node::Kind::Suffix:
-    case Node::Kind::ThinFunctionType:
-    case Node::Kind::TupleElement:
-    case Node::Kind::TypeMangling:
-    case Node::Kind::TypeMetadata:
-    case Node::Kind::TypeMetadataAccessFunction:
-    case Node::Kind::TypeMetadataCompletionFunction:
-    case Node::Kind::TypeMetadataInstantiationCache:
-    case Node::Kind::TypeMetadataInstantiationFunction:
-    case Node::Kind::TypeMetadataSingletonInitializationCache:
-    case Node::Kind::TypeMetadataDemanglingCache:
-    case Node::Kind::TypeMetadataLazyCache:
-    case Node::Kind::UncurriedFunctionType:
+  case Node::Kind::ConstrainedExistential:
+  case Node::Kind::PackElement:
+  case Node::Kind::PackElementLevel:
+  case Node::Kind::PackExpansion:
+  case Node::Kind::ProtocolListWithClass:
+  case Node::Kind::AccessorAttachedMacroExpansion:
+  case Node::Kind::AccessorFunctionReference:
+  case Node::Kind::Allocator:
+  case Node::Kind::ArgumentTuple:
+  case Node::Kind::AssociatedConformanceDescriptor:
+  case Node::Kind::AssociatedTypeDescriptor:
+  case Node::Kind::AssociatedTypeMetadataAccessor:
+  case Node::Kind::AssociatedTypeWitnessTableAccessor:
+  case Node::Kind::AsyncRemoved:
+  case Node::Kind::AutoClosureType:
+  case Node::Kind::BaseConformanceDescriptor:
+  case Node::Kind::BaseWitnessTableAccessor:
+  case Node::Kind::BodyAttachedMacroExpansion:
+  case Node::Kind::ClangType:
+  case Node::Kind::ClassMetadataBaseOffset:
+  case Node::Kind::CFunctionPointer:
+  case Node::Kind::ConformanceAttachedMacroExpansion:
+  case Node::Kind::Constructor:
+  case Node::Kind::CoroutineContinuationPrototype:
+  case Node::Kind::CurryThunk:
+  case Node::Kind::SILThunkIdentity:
+  case Node::Kind::DispatchThunk:
+  case Node::Kind::Deallocator:
+  case Node::Kind::IsolatedDeallocator:
+  case Node::Kind::DeclContext:
+  case Node::Kind::DefaultArgumentInitializer:
+  case Node::Kind::DefaultAssociatedTypeMetadataAccessor:
+  case Node::Kind::DefaultAssociatedConformanceAccessor:
+  case Node::Kind::DependentAssociatedTypeRef:
+  case Node::Kind::DependentGenericSignature:
+  case Node::Kind::DependentGenericParamPackMarker:
+  case Node::Kind::DependentGenericParamCount:
+  case Node::Kind::DependentGenericConformanceRequirement:
+  case Node::Kind::DependentGenericLayoutRequirement:
+  case Node::Kind::DependentGenericSameTypeRequirement:
+  case Node::Kind::DependentGenericSameShapeRequirement:
+  case Node::Kind::DependentPseudogenericSignature:
+  case Node::Kind::Destructor:
+  case Node::Kind::DidSet:
+  case Node::Kind::DirectMethodReferenceAttribute:
+  case Node::Kind::Directness:
+  case Node::Kind::DynamicAttribute:
+  case Node::Kind::EscapingAutoClosureType:
+  case Node::Kind::EscapingObjCBlock:
+  case Node::Kind::NoEscapeFunctionType:
+  case Node::Kind::ExplicitClosure:
+  case Node::Kind::Extension:
+  case Node::Kind::ExtensionAttachedMacroExpansion:
+  case Node::Kind::EnumCase:
+  case Node::Kind::FieldOffset:
+  case Node::Kind::FreestandingMacroExpansion:
+  case Node::Kind::FullObjCResilientClassStub:
+  case Node::Kind::FullTypeMetadata:
+  case Node::Kind::Function:
+  case Node::Kind::FunctionSignatureSpecialization:
+  case Node::Kind::FunctionSignatureSpecializationParam:
+  case Node::Kind::FunctionSignatureSpecializationReturn:
+  case Node::Kind::FunctionSignatureSpecializationParamKind:
+  case Node::Kind::FunctionSignatureSpecializationParamPayload:
+  case Node::Kind::FunctionType:
+  case Node::Kind::GenericProtocolWitnessTable:
+  case Node::Kind::GenericProtocolWitnessTableInstantiationFunction:
+  case Node::Kind::GenericPartialSpecialization:
+  case Node::Kind::GenericPartialSpecializationNotReAbstracted:
+  case Node::Kind::GenericSpecialization:
+  case Node::Kind::GenericSpecializationNotReAbstracted:
+  case Node::Kind::GenericSpecializationInResilienceDomain:
+  case Node::Kind::GenericSpecializationParam:
+  case Node::Kind::GenericSpecializationPrespecialized:
+  case Node::Kind::InlinedGenericFunction:
+  case Node::Kind::GenericTypeMetadataPattern:
+  case Node::Kind::Getter:
+  case Node::Kind::Global:
+  case Node::Kind::GlobalGetter:
+  case Node::Kind::Identifier:
+  case Node::Kind::Index:
+  case Node::Kind::InitAccessor:
+  case Node::Kind::IVarInitializer:
+  case Node::Kind::IVarDestroyer:
+  case Node::Kind::ImplDifferentiabilityKind:
+  case Node::Kind::ImplEscaping:
+  case Node::Kind::ImplErasedIsolation:
+  case Node::Kind::ImplSendingResult:
+  case Node::Kind::ImplConvention:
+  case Node::Kind::ImplParameterResultDifferentiability:
+  case Node::Kind::ImplParameterSending:
+  case Node::Kind::ImplParameterIsolated:
+  case Node::Kind::ImplParameterImplicitLeading:
+  case Node::Kind::ImplFunctionAttribute:
+  case Node::Kind::ImplFunctionConvention:
+  case Node::Kind::ImplFunctionConventionName:
+  case Node::Kind::ImplFunctionType:
+  case Node::Kind::ImplCoroutineKind:
+  case Node::Kind::ImplInvocationSubstitutions:
+  case Node::Kind::ImplPatternSubstitutions:
+  case Node::Kind::ImplicitClosure:
+  case Node::Kind::ImplParameter:
+  case Node::Kind::ImplResult:
+  case Node::Kind::ImplYield:
+  case Node::Kind::ImplErrorResult:
+  case Node::Kind::InOut:
+  case Node::Kind::InfixOperator:
+  case Node::Kind::Initializer:
+  case Node::Kind::Isolated:
+  case Node::Kind::Sending:
+  case Node::Kind::CompileTimeLiteral:
+  case Node::Kind::ConstValue:
+  case Node::Kind::PropertyWrapperBackingInitializer:
+  case Node::Kind::PropertyWrappedFieldInitAccessor:
+  case Node::Kind::PropertyWrapperInitFromProjectedValue:
+  case Node::Kind::KeyPathGetterThunkHelper:
+  case Node::Kind::KeyPathSetterThunkHelper:
+  case Node::Kind::KeyPathUnappliedMethodThunkHelper:
+  case Node::Kind::KeyPathAppliedMethodThunkHelper:
+  case Node::Kind::KeyPathEqualsThunkHelper:
+  case Node::Kind::KeyPathHashThunkHelper:
+  case Node::Kind::LazyProtocolWitnessTableAccessor:
+  case Node::Kind::LazyProtocolWitnessTableCacheVariable:
+  case Node::Kind::LocalDeclName:
+  case Node::Kind::Macro:
+  case Node::Kind::MacroExpansionLoc:
+  case Node::Kind::MacroExpansionUniqueName:
+  case Node::Kind::MaterializeForSet:
+  case Node::Kind::MemberAttributeAttachedMacroExpansion:
+  case Node::Kind::MemberAttachedMacroExpansion:
+  case Node::Kind::MergedFunction:
+  case Node::Kind::Metaclass:
+  case Node::Kind::MethodDescriptor:
+  case Node::Kind::MethodLookupFunction:
+  case Node::Kind::ModifyAccessor:
+  case Node::Kind::Modify2Accessor:
+  case Node::Kind::NativeOwningAddressor:
+  case Node::Kind::NativeOwningMutableAddressor:
+  case Node::Kind::NativePinningAddressor:
+  case Node::Kind::NativePinningMutableAddressor:
+  case Node::Kind::NominalTypeDescriptor:
+  case Node::Kind::NominalTypeDescriptorRecord:
+  case Node::Kind::NonObjCAttribute:
+  case Node::Kind::Number:
+  case Node::Kind::ObjCAsyncCompletionHandlerImpl:
+  case Node::Kind::ObjCAttribute:
+  case Node::Kind::ObjCBlock:
+  case Node::Kind::ObjCMetadataUpdateFunction:
+  case Node::Kind::ObjCResilientClassStub:
+  case Node::Kind::OpaqueTypeDescriptor:
+  case Node::Kind::OpaqueTypeDescriptorRecord:
+  case Node::Kind::OpaqueTypeDescriptorAccessor:
+  case Node::Kind::OpaqueTypeDescriptorAccessorImpl:
+  case Node::Kind::OpaqueTypeDescriptorAccessorKey:
+  case Node::Kind::OpaqueTypeDescriptorAccessorVar:
+  case Node::Kind::Owned:
+  case Node::Kind::OwningAddressor:
+  case Node::Kind::OwningMutableAddressor:
+  case Node::Kind::PartialApplyForwarder:
+  case Node::Kind::PartialApplyObjCForwarder:
+  case Node::Kind::PeerAttachedMacroExpansion:
+  case Node::Kind::PostfixOperator:
+  case Node::Kind::PreambleAttachedMacroExpansion:
+  case Node::Kind::PredefinedObjCAsyncCompletionHandlerImpl:
+  case Node::Kind::PrefixOperator:
+  case Node::Kind::PrivateDeclName:
+  case Node::Kind::PropertyDescriptor:
+  case Node::Kind::ProtocolConformance:
+  case Node::Kind::ProtocolConformanceDescriptor:
+  case Node::Kind::ProtocolConformanceDescriptorRecord:
+  case Node::Kind::MetadataInstantiationCache:
+  case Node::Kind::ProtocolDescriptor:
+  case Node::Kind::ProtocolDescriptorRecord:
+  case Node::Kind::ProtocolRequirementsBaseDescriptor:
+  case Node::Kind::ProtocolSelfConformanceDescriptor:
+  case Node::Kind::ProtocolSelfConformanceWitness:
+  case Node::Kind::ProtocolSelfConformanceWitnessTable:
+  case Node::Kind::ProtocolWitness:
+  case Node::Kind::ProtocolWitnessTable:
+  case Node::Kind::ProtocolWitnessTableAccessor:
+  case Node::Kind::ProtocolWitnessTablePattern:
+  case Node::Kind::ReabstractionThunk:
+  case Node::Kind::ReabstractionThunkHelper:
+  case Node::Kind::ReabstractionThunkHelperWithSelf:
+  case Node::Kind::ReabstractionThunkHelperWithGlobalActor:
+  case Node::Kind::ReadAccessor:
+  case Node::Kind::Read2Accessor:
+  case Node::Kind::RelatedEntityDeclName:
+  case Node::Kind::RetroactiveConformance:
+  case Node::Kind::Setter:
+  case Node::Kind::Shared:
+  case Node::Kind::SILBoxLayout:
+  case Node::Kind::SILBoxMutableField:
+  case Node::Kind::SILBoxImmutableField:
+  case Node::Kind::IsSerialized:
+  case Node::Kind::DroppedArgument:
+  case Node::Kind::SpecializationPassID:
+  case Node::Kind::Static:
+  case Node::Kind::Subscript:
+  case Node::Kind::Suffix:
+  case Node::Kind::ThinFunctionType:
+  case Node::Kind::TupleElement:
+  case Node::Kind::TypeMangling:
+  case Node::Kind::TypeMetadata:
+  case Node::Kind::TypeMetadataAccessFunction:
+  case Node::Kind::TypeMetadataCompletionFunction:
+  case Node::Kind::TypeMetadataInstantiationCache:
+  case Node::Kind::TypeMetadataInstantiationFunction:
+  case Node::Kind::TypeMetadataSingletonInitializationCache:
+  case Node::Kind::TypeMetadataDemanglingCache:
+  case Node::Kind::TypeMetadataLazyCache:
+  case Node::Kind::UncurriedFunctionType:
 #define REF_STORAGE(Name, ...) \
     case Node::Kind::Name:
 #include "swift/AST/ReferenceStorage.def"
@@ -589,6 +547,7 @@ class NodePrinter {
     case Node::Kind::OutlinedRetain:
     case Node::Kind::OutlinedRelease:
     case Node::Kind::OutlinedInitializeWithTake:
+    case Node::Kind::OutlinedInitializeWithTakeNoValueWitness:
     case Node::Kind::OutlinedInitializeWithCopy:
     case Node::Kind::OutlinedAssignWithTake:
     case Node::Kind::OutlinedAssignWithCopy:
@@ -615,6 +574,7 @@ class NodePrinter {
     case Node::Kind::DependentProtocolConformanceAssociated:
     case Node::Kind::DependentProtocolConformanceInherited:
     case Node::Kind::DependentProtocolConformanceRoot:
+    case Node::Kind::DependentProtocolConformanceOpaque:
     case Node::Kind::ProtocolConformanceRefInTypeModule:
     case Node::Kind::ProtocolConformanceRefInProtocolModule:
     case Node::Kind::ProtocolConformanceRefInOtherModule:
@@ -662,600 +622,553 @@ class NodePrinter {
     case Node::Kind::DependentGenericParamValueMarker:
     case Node::Kind::CoroFunctionPointer:
     case Node::Kind::DefaultOverride:
+    case Node::Kind::BorrowAccessor:
+    case Node::Kind::MutateAccessor:
       return false;
     }
     printer_unreachable("bad node kind");
-  }
+}
 
-  void printWithParens(NodePointer type, unsigned depth) {
-    bool needs_parens = !isSimpleType(type);
-    if (needs_parens)
-      Printer << "(";
-    print(type, depth + 1);
-    if (needs_parens)
-      Printer << ")";
-  }
+void NodePrinter::printWithParens(NodePointer type, unsigned depth) {
+  bool needs_parens = !isSimpleType(type);
+  if (needs_parens)
+    Printer << "(";
+  print(type, depth + 1);
+  if (needs_parens)
+    Printer << ")";
+}
 
-  SugarType findSugar(NodePointer Node) {
-    if (Node->getNumChildren() == 1 &&
-        Node->getKind() == Node::Kind::Type)
-      return findSugar(Node->getChild(0));
-    
-    if (Node->getNumChildren() != 2)
-      return SugarType::None;
-    
-    if (Node->getKind() != Node::Kind::BoundGenericEnum &&
-        Node->getKind() != Node::Kind::BoundGenericStructure)
-      return SugarType::None;
-
-    auto unboundType = Node->getChild(0)->getChild(0); // drill through Type
-    auto typeArgs = Node->getChild(1);
-    
-    if (Node->getKind() == Node::Kind::BoundGenericEnum) {
-      // Swift.Optional
-      if (isIdentifier(unboundType->getChild(1), "Optional") &&
-          typeArgs->getNumChildren() == 1 &&
-          isSwiftModule(unboundType->getChild(0))) {
-        return SugarType::Optional;
-      }
+NodePrinter::SugarType NodePrinter::findSugar(NodePointer Node) {
+  if (Node->getNumChildren() == 1 && Node->getKind() == Node::Kind::Type)
+    return findSugar(Node->getChild(0));
 
-      // Swift.ImplicitlyUnwrappedOptional
-      if (isIdentifier(unboundType->getChild(1), 
-                       "ImplicitlyUnwrappedOptional") &&
-          typeArgs->getNumChildren() == 1 &&
-          isSwiftModule(unboundType->getChild(0))) {
-        return SugarType::ImplicitlyUnwrappedOptional;
-      }
+  if (Node->getNumChildren() != 2)
+    return SugarType::None;
 
-      return SugarType::None;
-    }
+  if (Node->getKind() != Node::Kind::BoundGenericEnum &&
+      Node->getKind() != Node::Kind::BoundGenericStructure)
+    return SugarType::None;
 
-    assert(Node->getKind() == Node::Kind::BoundGenericStructure);
+  auto unboundType = Node->getChild(0)->getChild(0); // drill through Type
+  auto typeArgs = Node->getChild(1);
 
-    // Array
-    if (isIdentifier(unboundType->getChild(1), "Array") &&
+  if (Node->getKind() == Node::Kind::BoundGenericEnum) {
+    // Swift.Optional
+    if (isIdentifier(unboundType->getChild(1), "Optional") &&
         typeArgs->getNumChildren() == 1 &&
         isSwiftModule(unboundType->getChild(0))) {
-      return SugarType::Array;
+      return SugarType::Optional;
     }
 
-    // Dictionary
-    if (isIdentifier(unboundType->getChild(1), "Dictionary") &&
-        typeArgs->getNumChildren() == 2 &&
+    // Swift.ImplicitlyUnwrappedOptional
+    if (isIdentifier(unboundType->getChild(1), "ImplicitlyUnwrappedOptional") &&
+        typeArgs->getNumChildren() == 1 &&
         isSwiftModule(unboundType->getChild(0))) {
-      return SugarType::Dictionary;
+      return SugarType::ImplicitlyUnwrappedOptional;
     }
 
     return SugarType::None;
   }
 
-  void printBoundGeneric(NodePointer Node, unsigned depth) {
-    if (Node->getNumChildren() < 2)
-      return;
-    if (Node->getNumChildren() != 2) {
-      printBoundGenericNoSugar(Node, depth);
-      return;
-    }
-
-    if (!Options.SynthesizeSugarOnTypes ||
-        Node->getKind() == Node::Kind::BoundGenericClass)
-    {
-      // no sugar here
-      printBoundGenericNoSugar(Node, depth);
-      return;
-    }
+  assert(Node->getKind() == Node::Kind::BoundGenericStructure);
 
-    // Print the conforming type for a "bound" protocol node "as" the protocol
-    // type.
-    if (Node->getKind() == Node::Kind::BoundGenericProtocol) {
-      printChildren(Node->getChild(1), depth);
-      Printer << " as ";
-      print(Node->getChild(0), depth + 1);
-      return;
-    }
+  // Array
+  if (isIdentifier(unboundType->getChild(1), "Array") &&
+      typeArgs->getNumChildren() == 1 &&
+      isSwiftModule(unboundType->getChild(0))) {
+    return SugarType::Array;
+  }
 
-    SugarType sugarType = findSugar(Node);
-    
-    switch (sugarType) {
-      case SugarType::None:
-        printBoundGenericNoSugar(Node, depth);
-        break;
-      case SugarType::Optional:
-      case SugarType::ImplicitlyUnwrappedOptional: {
-        NodePointer type = Node->getChild(1)->getChild(0);
-        printWithParens(type, depth);
-        Printer << (sugarType == SugarType::Optional ? "?" : "!");
-        break;
-      }
-      case SugarType::Array: {
-        NodePointer type = Node->getChild(1)->getChild(0);
-        Printer << "[";
-        print(type, depth + 1);
-        Printer << "]";
-        break;
-      }
-      case SugarType::Dictionary: {
-        NodePointer keyType = Node->getChild(1)->getChild(0);
-        NodePointer valueType = Node->getChild(1)->getChild(1);
-        Printer << "[";
-        print(keyType, depth + 1);
-        Printer << " : ";
-        print(valueType, depth + 1);
-        Printer << "]";
-        break;
-      }
-    }
+  // Dictionary
+  if (isIdentifier(unboundType->getChild(1), "Dictionary") &&
+      typeArgs->getNumChildren() == 2 &&
+      isSwiftModule(unboundType->getChild(0))) {
+    return SugarType::Dictionary;
   }
 
-  NodePointer getChildIf(NodePointer Node, Node::Kind Kind) {
-    auto result =
-        std::find_if(Node->begin(), Node->end(), [&](NodePointer child) {
-          return child->getKind() == Kind;
-        });
-    return result != Node->end() ? *result : nullptr;
+  return SugarType::None;
+}
+
+void NodePrinter::printBoundGeneric(NodePointer Node, unsigned depth) {
+  if (Node->getNumChildren() < 2)
+    return;
+  if (Node->getNumChildren() != 2) {
+    printBoundGenericNoSugar(Node, depth);
+    return;
   }
 
-  void printFunctionParameters(NodePointer LabelList, NodePointer ParameterType,
-                               unsigned depth, bool showTypes) {
-    if (ParameterType->getKind() != Node::Kind::ArgumentTuple) {
-      setInvalid();
-      return;
-    }
+  if (!Options.SynthesizeSugarOnTypes ||
+      Node->getKind() == Node::Kind::BoundGenericClass) {
+    // no sugar here
+    printBoundGenericNoSugar(Node, depth);
+    return;
+  }
 
-    NodePointer Parameters = ParameterType->getFirstChild();
-    assert(Parameters->getKind() == Node::Kind::Type);
-    Parameters = Parameters->getFirstChild();
-    if (Parameters->getKind() != Node::Kind::Tuple) {
-      // only a single not-named parameter
-      if (showTypes) {
-        Printer << '(';
-        print(Parameters, depth + 1);
-        Printer << ')';
-      } else {
-        Printer << "(_:)";
-      }
-      return;
-    }
+  // Print the conforming type for a "bound" protocol node "as" the protocol
+  // type.
+  if (Node->getKind() == Node::Kind::BoundGenericProtocol) {
+    printChildren(Node->getChild(1), depth);
+    Printer << " as ";
+    print(Node->getChild(0), depth + 1);
+    return;
+  }
 
-    auto getLabelFor = [&](NodePointer Param, unsigned Index) -> std::string {
-      auto Label = LabelList->getChild(Index);
-      assert(Label && (Label->getKind() == Node::Kind::Identifier ||
-                       Label->getKind() == Node::Kind::FirstElementMarker));
-      return Label->getKind() == Node::Kind::Identifier ? Label->getText().str()
-                                                        : "_";
-    };
-
-    unsigned ParamIndex = 0;
-    bool hasLabels = LabelList && LabelList->getNumChildren() > 0;
-
-    Printer << '(';
-    llvm::interleave(
-        Parameters->begin(), Parameters->end(),
-        [&](NodePointer Param) {
-          assert(Param->getKind() == Node::Kind::TupleElement);
-
-          if (hasLabels) {
-            Printer << getLabelFor(Param, ParamIndex) << ':';
-          } else if (!showTypes) {
-            if (auto Label = getChildIf(Param, Node::Kind::TupleElementName))
-              Printer << Label->getText() << ":";
-            else
-              Printer << "_:";
-          }
+  SugarType sugarType = findSugar(Node);
 
-          if (hasLabels && showTypes)
-            Printer << ' ';
+  switch (sugarType) {
+  case SugarType::None:
+    printBoundGenericNoSugar(Node, depth);
+    break;
+  case SugarType::Optional:
+  case SugarType::ImplicitlyUnwrappedOptional: {
+    NodePointer type = Node->getChild(1)->getChild(0);
+    printWithParens(type, depth);
+    Printer << (sugarType == SugarType::Optional ? "?" : "!");
+    break;
+  }
+  case SugarType::Array: {
+    NodePointer type = Node->getChild(1)->getChild(0);
+    Printer << "[";
+    print(type, depth + 1);
+    Printer << "]";
+    break;
+  }
+  case SugarType::Dictionary: {
+    NodePointer keyType = Node->getChild(1)->getChild(0);
+    NodePointer valueType = Node->getChild(1)->getChild(1);
+    Printer << "[";
+    print(keyType, depth + 1);
+    Printer << " : ";
+    print(valueType, depth + 1);
+    Printer << "]";
+    break;
+  }
+  }
+}
 
-          ++ParamIndex;
+NodePointer NodePrinter::getChildIf(NodePointer Node, Node::Kind Kind) {
+  auto result =
+      std::find_if(Node->begin(), Node->end(),
+                   [&](NodePointer child) { return child->getKind() == Kind; });
+  return result != Node->end() ? *result : nullptr;
+}
 
-          if (showTypes)
-            print(Param, depth + 1);
-        },
-        [&]() { Printer << (showTypes ? ", " : ""); });
-    Printer << ')';
+void NodePrinter::printFunctionParameters(NodePointer LabelList,
+                                          NodePointer ParameterType,
+                                          unsigned depth, bool showTypes) {
+  if (ParameterType->getKind() != Node::Kind::ArgumentTuple) {
+    setInvalid();
+    return;
   }
 
-  void printFunctionType(NodePointer LabelList, NodePointer node,
-                         unsigned depth) {
-    if (node->getNumChildren() < 2) {
-      setInvalid();
-      return;
+  NodePointer Parameters = ParameterType->getFirstChild();
+  assert(Parameters->getKind() == Node::Kind::Type);
+  Parameters = Parameters->getFirstChild();
+  if (Parameters->getKind() != Node::Kind::Tuple) {
+    // only a single not-named parameter
+    if (showTypes) {
+      Printer << '(';
+      print(Parameters, depth + 1);
+      Printer << ')';
+    } else {
+      Printer << "(_:)";
     }
+    return;
+  }
 
-    auto printConventionWithMangledCType = [this, node,
-                                            depth](const char *convention) {
-      Printer << "@convention(" << convention;
-      if (node->getFirstChild()->getKind() == Node::Kind::ClangType) {
-        Printer << ", mangledCType: \"";
-        print(node->getFirstChild(), depth + 1);
-        Printer << '"';
-      }
-      Printer << ") ";
-    };
+  auto getLabelFor = [&](NodePointer Param, unsigned Index) -> std::string {
+    auto Label = LabelList->getChild(Index);
+    assert(Label && (Label->getKind() == Node::Kind::Identifier ||
+                     Label->getKind() == Node::Kind::FirstElementMarker));
+    return Label->getKind() == Node::Kind::Identifier ? Label->getText().str()
+                                                      : "_";
+  };
 
-    switch (node->getKind()) {
-    case Node::Kind::FunctionType:
-    case Node::Kind::UncurriedFunctionType:
-    case Node::Kind::NoEscapeFunctionType:
-      break;
-    case Node::Kind::AutoClosureType:
-    case Node::Kind::EscapingAutoClosureType:
-      Printer << "@autoclosure "; break;
-    case Node::Kind::ThinFunctionType:
-      Printer << "@convention(thin) "; break;
-    case Node::Kind::CFunctionPointer:
-      printConventionWithMangledCType("c");
-      break;
-    case Node::Kind::EscapingObjCBlock:
-      Printer << "@escaping ";
-      LLVM_FALLTHROUGH;
-    case Node::Kind::ObjCBlock:
-      printConventionWithMangledCType("block");
-      break;
-    default:
-      assert(false && "Unhandled function type in printFunctionType!");
+  unsigned ParamIndex = 0;
+  bool hasLabels = LabelList && LabelList->getNumChildren() > 0;
+
+  Printer << '(';
+  llvm::interleave(
+      Parameters->begin(), Parameters->end(),
+      [&](NodePointer Param) {
+        assert(Param->getKind() == Node::Kind::TupleElement);
+
+        if (hasLabels) {
+          Printer << getLabelFor(Param, ParamIndex) << ':';
+        } else if (!showTypes) {
+          if (auto Label = getChildIf(Param, Node::Kind::TupleElementName))
+            Printer << Label->getText() << ":";
+          else
+            Printer << "_:";
+        }
+
+        if (hasLabels && showTypes)
+          Printer << ' ';
+
+        ++ParamIndex;
+
+        if (showTypes)
+          print(Param, depth + 1);
+      },
+      [&]() { Printer << (showTypes ? ", " : ""); });
+  Printer << ')';
+}
+
+void NodePrinter::printFunctionType(NodePointer LabelList, NodePointer node,
+                                    unsigned depth) {
+  if (node->getNumChildren() < 2) {
+    setInvalid();
+    return;
+  }
+
+  auto printConventionWithMangledCType = [this, node,
+                                          depth](const char *convention) {
+    Printer << "@convention(" << convention;
+    if (node->getFirstChild()->getKind() == Node::Kind::ClangType) {
+      Printer << ", mangledCType: \"";
+      print(node->getFirstChild(), depth + 1);
+      Printer << '"';
     }
+    Printer << ") ";
+  };
 
-    unsigned argIndex = node->getNumChildren() - 2;
-    unsigned startIndex = 0;
-    bool isSendable = false, isAsync = false, hasSendingResult = false;
-    auto diffKind = MangledDifferentiabilityKind::NonDifferentiable;
-    if (node->getChild(startIndex)->getKind() == Node::Kind::ClangType) {
-      // handled earlier
-      ++startIndex;
-    }
+  switch (node->getKind()) {
+  case Node::Kind::FunctionType:
+  case Node::Kind::UncurriedFunctionType:
+  case Node::Kind::NoEscapeFunctionType:
+    break;
+  case Node::Kind::AutoClosureType:
+  case Node::Kind::EscapingAutoClosureType:
+    Printer << "@autoclosure ";
+    break;
+  case Node::Kind::ThinFunctionType:
+    Printer << "@convention(thin) ";
+    break;
+  case Node::Kind::CFunctionPointer:
+    printConventionWithMangledCType("c");
+    break;
+  case Node::Kind::EscapingObjCBlock:
+    Printer << "@escaping ";
+    LLVM_FALLTHROUGH;
+  case Node::Kind::ObjCBlock:
+    printConventionWithMangledCType("block");
+    break;
+  default:
+    assert(false && "Unhandled function type in printFunctionType!");
+  }
 
-    // Be sure to check for function signature components in the same
-    // order that they're added by the demangler, which is the reverse
-    // of the order that they appear in the mangling grammar.
+  unsigned argIndex = node->getNumChildren() - 2;
+  unsigned startIndex = 0;
+  bool isSendable = false, isAsync = false, hasSendingResult = false;
+  auto diffKind = MangledDifferentiabilityKind::NonDifferentiable;
+  if (node->getChild(startIndex)->getKind() == Node::Kind::ClangType) {
+    // handled earlier
+    ++startIndex;
+  }
 
-    if (node->getChild(startIndex)->getKind() ==
-        Node::Kind::SendingResultFunctionType) {
-      ++startIndex;
-      hasSendingResult = true;
-    }
+  // Be sure to check for function signature components in the same
+  // order that they're added by the demangler, which is the reverse
+  // of the order that they appear in the mangling grammar.
 
-    // function-isolation; note that these can't actually both appear.
-    if (node->getChild(startIndex)->getKind()
-            == Node::Kind::IsolatedAnyFunctionType) {
-      print(node->getChild(startIndex), depth + 1);
-      ++startIndex;
-    }
+  if (node->getChild(startIndex)->getKind() ==
+      Node::Kind::SendingResultFunctionType) {
+    ++startIndex;
+    hasSendingResult = true;
+  }
 
-    Node *nonIsolatedCallerNode = nullptr;
-    if (node->getChild(startIndex)->getKind() ==
-          Node::Kind::NonIsolatedCallerFunctionType) {
-      nonIsolatedCallerNode = node->getChild(startIndex);
-      ++startIndex;
-    }
+  // function-isolation; note that these can't actually both appear.
+  if (node->getChild(startIndex)->getKind() ==
+      Node::Kind::IsolatedAnyFunctionType) {
+    print(node->getChild(startIndex), depth + 1);
+    ++startIndex;
+  }
 
-    if (node->getChild(startIndex)->getKind() ==
-          Node::Kind::GlobalActorFunctionType) {
-      print(node->getChild(startIndex), depth + 1);
-      ++startIndex;
-    }
+  Node *nonIsolatedCallerNode = nullptr;
+  if (node->getChild(startIndex)->getKind() ==
+      Node::Kind::NonIsolatedCallerFunctionType) {
+    nonIsolatedCallerNode = node->getChild(startIndex);
+    ++startIndex;
+  }
 
-    if (node->getChild(startIndex)->getKind() ==
-        Node::Kind::DifferentiableFunctionType) {
-      diffKind =
-          (MangledDifferentiabilityKind)node->getChild(startIndex)->getIndex();
-      ++startIndex;
-    }
+  if (node->getChild(startIndex)->getKind() ==
+      Node::Kind::GlobalActorFunctionType) {
+    print(node->getChild(startIndex), depth + 1);
+    ++startIndex;
+  }
 
-    Node *thrownErrorNode = nullptr;
-    if (node->getChild(startIndex)->getKind() == Node::Kind::ThrowsAnnotation ||
-        node->getChild(startIndex)->getKind()
-          == Node::Kind::TypedThrowsAnnotation) {
-      thrownErrorNode = node->getChild(startIndex);
-      ++startIndex;
-    }
+  if (node->getChild(startIndex)->getKind() ==
+      Node::Kind::DifferentiableFunctionType) {
+    diffKind =
+        (MangledDifferentiabilityKind)node->getChild(startIndex)->getIndex();
+    ++startIndex;
+  }
 
-    if (node->getChild(startIndex)->getKind()
-            == Node::Kind::ConcurrentFunctionType) {
-      ++startIndex;
-      isSendable = true;
-    }
-    if (node->getChild(startIndex)->getKind() == Node::Kind::AsyncAnnotation) {
-      ++startIndex;
-      isAsync = true;
-    }
+  Node *thrownErrorNode = nullptr;
+  if (node->getChild(startIndex)->getKind() == Node::Kind::ThrowsAnnotation ||
+      node->getChild(startIndex)->getKind() ==
+          Node::Kind::TypedThrowsAnnotation) {
+    thrownErrorNode = node->getChild(startIndex);
+    ++startIndex;
+  }
 
-    switch (diffKind) {
-    case MangledDifferentiabilityKind::Forward:
-      Printer << "@differentiable(_forward) ";
-      break;
-    case MangledDifferentiabilityKind::Reverse:
-      Printer << "@differentiable(reverse) ";
-      break;
-    case MangledDifferentiabilityKind::Linear:
-      Printer << "@differentiable(_linear) ";
-      break;
-    case MangledDifferentiabilityKind::Normal:
-      Printer << "@differentiable ";
-      break;
-    case MangledDifferentiabilityKind::NonDifferentiable:
-      break;
-    }
+  if (node->getChild(startIndex)->getKind() ==
+      Node::Kind::ConcurrentFunctionType) {
+    ++startIndex;
+    isSendable = true;
+  }
+  if (node->getChild(startIndex)->getKind() == Node::Kind::AsyncAnnotation) {
+    ++startIndex;
+    isAsync = true;
+  }
 
-    if (nonIsolatedCallerNode)
-      print(nonIsolatedCallerNode, depth + 1);
+  switch (diffKind) {
+  case MangledDifferentiabilityKind::Forward:
+    Printer << "@differentiable(_forward) ";
+    break;
+  case MangledDifferentiabilityKind::Reverse:
+    Printer << "@differentiable(reverse) ";
+    break;
+  case MangledDifferentiabilityKind::Linear:
+    Printer << "@differentiable(_linear) ";
+    break;
+  case MangledDifferentiabilityKind::Normal:
+    Printer << "@differentiable ";
+    break;
+  case MangledDifferentiabilityKind::NonDifferentiable:
+    break;
+  }
 
-    if (isSendable)
-      Printer << "@Sendable ";
+  if (nonIsolatedCallerNode)
+    print(nonIsolatedCallerNode, depth + 1);
 
-    printFunctionParameters(LabelList, node->getChild(argIndex), depth,
-                            Options.ShowFunctionArgumentTypes);
+  if (isSendable)
+    Printer << "@Sendable ";
 
-    if (!Options.ShowFunctionArgumentTypes)
-      return;
+  printFunctionParameters(LabelList, node->getChild(argIndex), depth,
+                          Options.ShowFunctionArgumentTypes);
 
-    if (isAsync)
-      Printer << " async";
+  if (!Options.ShowFunctionArgumentTypes)
+    return;
 
-    if (thrownErrorNode) {
-      print(thrownErrorNode, depth + 1);
-    }
+  if (isAsync)
+    Printer << " async";
 
-    Printer << " -> ";
+  if (thrownErrorNode) {
+    print(thrownErrorNode, depth + 1);
+  }
 
-    if (hasSendingResult)
-      Printer << "sending ";
+  Printer << " -> ";
 
-    print(node->getChild(argIndex + 1), depth + 1);
-  }
+  if (hasSendingResult)
+    Printer << "sending ";
 
-  void printImplFunctionType(NodePointer fn, unsigned depth) {
-    NodePointer patternSubs = nullptr;
-    NodePointer invocationSubs = nullptr;
-    NodePointer sendingResult = nullptr;
-    enum State { Attrs, Inputs, Results } curState = Attrs;
-    auto transitionTo = [&](State newState) {
-      assert(newState >= curState);
-      for (; curState != newState; curState = State(curState + 1)) {
-        switch (curState) {
-        case Attrs:
-          if (patternSubs) {
-            Printer << "@substituted ";
-            print(patternSubs->getChild(0), depth + 1);
-            Printer << ' ';
-          }
-          Printer << '(';
-          continue;
-        case Inputs:
-          Printer << ") -> ";
-          if (sendingResult) {
-            print(sendingResult, depth + 1);
-            Printer << " ";
-          }
-          Printer << "(";
-          continue;
-        case Results: printer_unreachable("no state after Results");
-        }
-        printer_unreachable("bad state");
-      }
-    };
+  print(node->getChild(argIndex + 1), depth + 1);
+}
 
-    for (auto &child : *fn) {
-      if (child->getKind() == Node::Kind::ImplParameter) {
-        if (curState == Inputs) Printer << ", ";
-        transitionTo(Inputs);
-        print(child, depth + 1);
-      } else if (child->getKind() == Node::Kind::ImplResult
-                 || child->getKind() == Node::Kind::ImplYield
-                 || child->getKind() == Node::Kind::ImplErrorResult) {
-        if (curState == Results) Printer << ", ";
-        transitionTo(Results);
-        print(child, depth + 1);
-      } else if (child->getKind() == Node::Kind::ImplPatternSubstitutions) {
-        patternSubs = child;
-      } else if (child->getKind() == Node::Kind::ImplInvocationSubstitutions) {
-        invocationSubs = child;
-      } else if (child->getKind() == Node::Kind::ImplSendingResult) {
-        sendingResult = child;
-      } else {
-        assert(curState == Attrs);
-        print(child, depth + 1);
-        Printer << ' ';
+void NodePrinter::printImplFunctionType(NodePointer fn, unsigned depth) {
+  NodePointer patternSubs = nullptr;
+  NodePointer invocationSubs = nullptr;
+  NodePointer sendingResult = nullptr;
+  enum State { Attrs, Inputs, Results } curState = Attrs;
+  auto transitionTo = [&](State newState) {
+    assert(newState >= curState);
+    for (; curState != newState; curState = State(curState + 1)) {
+      switch (curState) {
+      case Attrs:
+        if (patternSubs) {
+          Printer << "@substituted ";
+          print(patternSubs->getChild(0), depth + 1);
+          Printer << ' ';
+        }
+        Printer << '(';
+        continue;
+      case Inputs:
+        Printer << ") -> ";
+        if (sendingResult) {
+          print(sendingResult, depth + 1);
+          Printer << " ";
+        }
+        Printer << "(";
+        continue;
+      case Results:
+        printer_unreachable("no state after Results");
       }
+      printer_unreachable("bad state");
     }
-    transitionTo(Results);
-    Printer << ')';
+  };
 
-    if (patternSubs) {
-      Printer << " for <";
-      printChildren(patternSubs->getChild(1), depth);
-      Printer << '>';
-    }
-    if (invocationSubs) {
-      Printer << " for <";
-      printChildren(invocationSubs->getChild(0), depth);
-      Printer << '>';
+  for (auto &child : *fn) {
+    if (child->getKind() == Node::Kind::ImplParameter) {
+      if (curState == Inputs)
+        Printer << ", ";
+      transitionTo(Inputs);
+      print(child, depth + 1);
+    } else if (child->getKind() == Node::Kind::ImplResult ||
+               child->getKind() == Node::Kind::ImplYield ||
+               child->getKind() == Node::Kind::ImplErrorResult) {
+      if (curState == Results)
+        Printer << ", ";
+      transitionTo(Results);
+      print(child, depth + 1);
+    } else if (child->getKind() == Node::Kind::ImplPatternSubstitutions) {
+      patternSubs = child;
+    } else if (child->getKind() == Node::Kind::ImplInvocationSubstitutions) {
+      invocationSubs = child;
+    } else if (child->getKind() == Node::Kind::ImplSendingResult) {
+      sendingResult = child;
+    } else {
+      assert(curState == Attrs);
+      print(child, depth + 1);
+      Printer << ' ';
     }
   }
+  transitionTo(Results);
+  Printer << ')';
+
+  if (patternSubs) {
+    Printer << " for <";
+    printChildren(patternSubs->getChild(1), depth);
+    Printer << '>';
+  }
+  if (invocationSubs) {
+    Printer << " for <";
+    printChildren(invocationSubs->getChild(0), depth);
+    Printer << '>';
+  }
+}
 
-  void printGenericSignature(NodePointer Node, unsigned depth) {
-    Printer << '<';
+void NodePrinter::printGenericSignature(NodePointer Node, unsigned depth) {
+  Printer << '<';
 
-    unsigned numChildren = Node->getNumChildren();
+  unsigned numChildren = Node->getNumChildren();
 
-    unsigned numGenericParams = 0;
-    for (; numGenericParams < numChildren; ++numGenericParams) {
-      if (Node->getChild(numGenericParams)->getKind()
-               != Node::Kind::DependentGenericParamCount) {
-        break;
-      }
+  unsigned numGenericParams = 0;
+  for (; numGenericParams < numChildren; ++numGenericParams) {
+    if (Node->getChild(numGenericParams)->getKind() !=
+        Node::Kind::DependentGenericParamCount) {
+      break;
     }
+  }
 
-    unsigned firstRequirement = numGenericParams;
-    for (; firstRequirement < numChildren; ++firstRequirement) {
-      auto child = Node->getChild(firstRequirement);
-      if (child->getKind() == Node::Kind::Type)
-        child = child->getChild(0);
-      if (child->getKind() != Node::Kind::DependentGenericParamPackMarker &&
-          child->getKind() != Node::Kind::DependentGenericParamValueMarker) {
-        break;
-      }
+  unsigned firstRequirement = numGenericParams;
+  for (; firstRequirement < numChildren; ++firstRequirement) {
+    auto child = Node->getChild(firstRequirement);
+    if (child->getKind() == Node::Kind::Type)
+      child = child->getChild(0);
+    if (child->getKind() != Node::Kind::DependentGenericParamPackMarker &&
+        child->getKind() != Node::Kind::DependentGenericParamValueMarker) {
+      break;
     }
+  }
 
-    auto isGenericParamPack = [&](unsigned depth, unsigned index) {
-      for (unsigned i = numGenericParams; i < firstRequirement; ++i) {
-        auto child = Node->getChild(i);
-        if (child->getKind() != Node::Kind::DependentGenericParamPackMarker)
-          continue;
-        child = child->getChild(0);
+  auto isGenericParamPack = [&](unsigned depth, unsigned index) {
+    for (unsigned i = numGenericParams; i < firstRequirement; ++i) {
+      auto child = Node->getChild(i);
+      if (child->getKind() != Node::Kind::DependentGenericParamPackMarker)
+        continue;
+      child = child->getChild(0);
 
-        if (child->getKind() != Node::Kind::Type)
-          continue;
+      if (child->getKind() != Node::Kind::Type)
+        continue;
 
-        child = child->getChild(0);
-        if (child->getKind() != Node::Kind::DependentGenericParamType)
-          continue;
+      child = child->getChild(0);
+      if (child->getKind() != Node::Kind::DependentGenericParamType)
+        continue;
 
-        if (index == child->getChild(0)->getIndex() &&
-            depth == child->getChild(1)->getIndex()) {
-          return true;
-        }
+      if (index == child->getChild(0)->getIndex() &&
+          depth == child->getChild(1)->getIndex()) {
+        return true;
       }
+    }
 
-      return false;
-    };
+    return false;
+  };
 
-    auto isGenericParamValue = [&](unsigned depth, unsigned index) {
-      for (unsigned i = numGenericParams; i < firstRequirement; ++i) {
-        auto child = Node->getChild(i);
-        if (child->getKind() != Node::Kind::DependentGenericParamValueMarker)
-          continue;
-        child = child->getChild(0);
+  auto isGenericParamValue = [&](unsigned depth, unsigned index) {
+    for (unsigned i = numGenericParams; i < firstRequirement; ++i) {
+      auto child = Node->getChild(i);
+      if (child->getKind() != Node::Kind::DependentGenericParamValueMarker)
+        continue;
+      child = child->getChild(0);
 
-        if (child->getKind() != Node::Kind::Type)
-          continue;
+      if (child->getKind() != Node::Kind::Type)
+        continue;
 
-        auto param = child->getChild(0);
-        auto type = child->getChild(1);
-        if (param->getKind() != Node::Kind::DependentGenericParamType)
-          continue;
+      auto param = child->getChild(0);
+      auto type = child->getChild(1);
+      if (param->getKind() != Node::Kind::DependentGenericParamType)
+        continue;
 
-        if (index == param->getChild(0)->getIndex() &&
-            depth == param->getChild(1)->getIndex()) {
-          return std::make_pair(true, type);
-        }
+      if (index == param->getChild(0)->getIndex() &&
+          depth == param->getChild(1)->getIndex()) {
+        return std::make_pair(true, type);
       }
+    }
 
-      return std::make_pair(false, NodePointer());
-    };
+    return std::make_pair(false, NodePointer());
+  };
 
-    unsigned gpDepth = 0;
-    for (; gpDepth < numGenericParams; ++gpDepth) {
-      if (gpDepth != 0)
-        Printer << "><";
+  unsigned gpDepth = 0;
+  for (; gpDepth < numGenericParams; ++gpDepth) {
+    if (gpDepth != 0)
+      Printer << "><";
 
-      unsigned count = Node->getChild(gpDepth)->getIndex();
-      for (unsigned index = 0; index < count; ++index) {
-        if (index != 0)
-          Printer << ", ";
+    unsigned count = Node->getChild(gpDepth)->getIndex();
+    for (unsigned index = 0; index < count; ++index) {
+      if (index != 0)
+        Printer << ", ";
 
-        // Limit the number of printed generic parameters. In practice this
-        // it will never be exceeded. The limit is only important for malformed
-        // symbols where count can be really huge.
-        if (index >= 128) {
-          Printer << "...";
-          break;
-        }
+      // Limit the number of printed generic parameters. In practice this
+      // it will never be exceeded. The limit is only important for malformed
+      // symbols where count can be really huge.
+      if (index >= 128) {
+        Printer << "...";
+        break;
+      }
 
-        if (isGenericParamPack(gpDepth, index))
-          Printer << "each ";
+      if (isGenericParamPack(gpDepth, index))
+        Printer << "each ";
 
-        auto value = isGenericParamValue(gpDepth, index);
+      auto value = isGenericParamValue(gpDepth, index);
 
-        if (value.first)
-          Printer << "let ";
+      if (value.first)
+        Printer << "let ";
 
-        // FIXME: Depth won't match when a generic signature applies to a
-        // method in generic type context.
-        Printer << Options.GenericParameterName(gpDepth, index);
+      // FIXME: Depth won't match when a generic signature applies to a
+      // method in generic type context.
+      Printer << Options.GenericParameterName(gpDepth, index);
 
-        if (value.second) {
-          Printer << ": ";
-          print(value.second, depth + 1);
-        }
+      if (value.second) {
+        Printer << ": ";
+        print(value.second, depth + 1);
       }
     }
+  }
 
-    if (firstRequirement != numChildren) {
-      if (Options.DisplayWhereClauses) {
-        Printer << " where ";
-        for (unsigned i = firstRequirement; i < numChildren; ++i) {
-          if (i > firstRequirement)
-            Printer << ", ";
-          print(Node->getChild(i), depth + 1);
-        }
+  if (firstRequirement != numChildren) {
+    if (Options.DisplayWhereClauses) {
+      Printer << " where ";
+      for (unsigned i = firstRequirement; i < numChildren; ++i) {
+        if (i > firstRequirement)
+          Printer << ", ";
+        print(Node->getChild(i), depth + 1);
       }
     }
-    Printer << '>';
   }
-
-  void printFunctionSigSpecializationParams(NodePointer Node, unsigned depth);
-
-  void printSpecializationPrefix(NodePointer node, StringRef Description,
-                                 unsigned depth,
-                                 StringRef ParamPrefix = StringRef());
-
-  /// The main big print function.
-  NodePointer print(NodePointer Node, unsigned depth,
-                    bool asPrefixContext = false);
-
-  NodePointer printAbstractStorage(NodePointer Node, unsigned depth,
-                                   bool asPrefixContent, StringRef ExtraName);
-
-  /// Utility function to print entities.
-  ///
-  /// \param Entity The entity node to print
-  /// \param depth The depth in the print() call tree.
-  /// \param asPrefixContext Should the entity printed as a context which as a
-  ///        prefix to another entity, e.g. the Abc in Abc.def()
-  /// \param TypePr How should the type of the entity be printed, if at all.
-  ///        E.g. with a colon for properties or as a function type.
-  /// \param hasName Does the entity has a name, e.g. a function in contrast to
-  ///        an initializer.
-  /// \param ExtraName An extra name added to the entity name (if any).
-  /// \param ExtraIndex An extra index added to the entity name (if any),
-  ///        e.g. closure #1
-  /// \param OverwriteName If non-empty, print this name instead of the one
-  ///        provided by the node. Gets printed even if hasName is false.
-  /// \return If a non-null node is returned it's a context which must be
-  ///         printed in postfix-form after the entity: "<entity> in <context>".
-  NodePointer printEntity(NodePointer Entity, unsigned depth,
-                          bool asPrefixContext, TypePrinting TypePr,
-                          bool hasName, StringRef ExtraName = "",
-                          int ExtraIndex = -1, StringRef OverwriteName = "");
-
-  /// Print the type of an entity.
-  ///
-  /// \param Entity The entity.
-  /// \param type The type of the entity.
-  /// \param genericFunctionTypeList If not null, the generic argument types
-  ///           which is printed in the generic signature.
-  /// \param depth The depth in the print() call tree.
-  void printEntityType(NodePointer Entity, NodePointer type,
-                       NodePointer genericFunctionTypeList, unsigned depth);
-};
-} // end anonymous namespace
-
-static bool isExistentialType(NodePointer node) {
-  return (node->getKind() == Node::Kind::ExistentialMetatype ||
-          node->getKind() == Node::Kind::ProtocolList ||
-          node->getKind() == Node::Kind::ProtocolListWithClass ||
-          node->getKind() == Node::Kind::ProtocolListWithAnyObject);
+  Printer << '>';
 }
 
 /// Print the relevant parameters and return the new index.
 void NodePrinter::printFunctionSigSpecializationParams(NodePointer Node,
                                                        unsigned depth) {
   unsigned Idx = 0;
+  unsigned argIdx = 0;
   unsigned End = Node->getNumChildren();
   while (Idx < End) {
-    NodePointer firstChild = Node->getChild(Idx);
-    unsigned V = firstChild->getIndex();
+    NodePointer child = Node->getChild(Idx);
+    if (!child->hasIndex())
+      return;
+    unsigned V = child->getIndex();
     auto K = FunctionSigSpecializationParamKind(V);
     switch (K) {
     case FunctionSigSpecializationParamKind::BoxToValue:
@@ -1268,18 +1181,14 @@ void NodePrinter::printFunctionSigSpecializationParams(NodePointer Node,
       Printer << "[";
       print(Node->getChild(Idx++), depth + 1);
       Printer << " : ";
-      const auto &text = Node->getChild(Idx++)->getText();
-      std::string demangledName = demangleSymbolAsString(text);
-      if (demangledName.empty()) {
-        Printer << text;
-      } else {
-        Printer << demangledName;
-      }
+      printNextParamChildNode(Node, argIdx, K, depth);
       Printer << "]";
       break;
     }
     case FunctionSigSpecializationParamKind::ConstantPropInteger:
     case FunctionSigSpecializationParamKind::ConstantPropFloat:
+      if (Idx + 2 > End)
+        return;
       Printer << "[";
       print(Node->getChild(Idx++), depth + 1);
       Printer << " : ";
@@ -1287,12 +1196,14 @@ void NodePrinter::printFunctionSigSpecializationParams(NodePointer Node,
       Printer << "]";
       break;
     case FunctionSigSpecializationParamKind::ConstantPropString:
+      if (Idx + 2 > End)
+        return;
       Printer << "[";
       print(Node->getChild(Idx++), depth + 1);
       Printer << " : ";
       print(Node->getChild(Idx++), depth + 1);
       Printer << "'";
-      print(Node->getChild(Idx++), depth + 1);
+      printNextParamChildNode(Node, argIdx, K, depth);
       Printer << "'";
       Printer << "]";
       break;
@@ -1300,14 +1211,23 @@ void NodePrinter::printFunctionSigSpecializationParams(NodePointer Node,
       Printer << "[";
       print(Node->getChild(Idx++), depth + 1);
       Printer << " : ";
-      print(Node->getChild(Idx++), depth + 1);
+      printNextParamChildNode(Node, argIdx, K, depth);
       Printer << "<";
-      print(Node->getChild(Idx++), depth + 1);
+      printNextParamChildNode(Node, argIdx, K, depth);
       Printer << ",";
-      print(Node->getChild(Idx++), depth + 1);
+      printNextParamChildNode(Node, argIdx, K, depth);
       Printer << ">]";
       break;
+    case FunctionSigSpecializationParamKind::ConstantPropStruct:
+      Printer << "[";
+      print(Node->getChild(Idx++), depth + 1);
+      Printer << " : ";
+      printNextParamChildNode(Node, argIdx, K, depth);
+      Printer << "]";
+      break;
     case FunctionSigSpecializationParamKind::ClosureProp:
+      if (Idx + 2 > End)
+        return;
       Printer << "[";
       print(Node->getChild(Idx++), depth + 1);
       Printer << " : ";
@@ -1327,6 +1247,15 @@ void NodePrinter::printFunctionSigSpecializationParams(NodePointer Node,
       }
       Printer << "]";
       break;
+    case FunctionSigSpecializationParamKind::ClosurePropPreviousArg:
+      if (Idx + 2 > End)
+        return;
+      Printer << "[";
+      print(Node->getChild(Idx++), depth + 1);
+      Printer << " ";
+      print(Node->getChild(Idx++), depth + 1);
+      Printer << "]";
+      break;
     default:
       assert(
        ((V & unsigned(FunctionSigSpecializationParamKind::OwnedToGuaranteed)) ||
@@ -1341,6 +1270,56 @@ void NodePrinter::printFunctionSigSpecializationParams(NodePointer Node,
   }
 }
 
+void NodePrinter::printNextParamChildNode(NodePointer nd, unsigned &idx,
+                                          FunctionSigSpecializationParamKind kind,
+                                          unsigned depth) {
+  while (idx < nd->getNumChildren()) {
+    NodePointer child = nd->getChild(idx++);
+    if (child->getKind() == Node::Kind::FunctionSignatureSpecializationParamKind ||
+        child->getKind() == Node::Kind::FunctionSignatureSpecializationParamPayload) {
+      continue;
+    }
+    switch (kind) {
+      case FunctionSigSpecializationParamKind::ConstantPropInteger:
+      case FunctionSigSpecializationParamKind::ConstantPropFloat: {
+        if (!child->hasText())
+          return;
+        const auto &text = child->getText();
+        std::string demangledName = demangleSymbolAsString(text);
+        if (demangledName.empty()) {
+          Printer << text;
+        } else {
+          Printer << demangledName;
+        }
+        break;
+      }
+      case FunctionSigSpecializationParamKind::ConstantPropString:
+        if (child->hasText()) {
+          StringRef text = child->getText();
+          if (!text.empty() && text[0] == '_') {
+            Printer << text.drop_front(1);
+            return;
+          }
+        }
+        print(child, depth + 1);
+        break;
+      case FunctionSigSpecializationParamKind::ConstantPropFunction:
+      case FunctionSigSpecializationParamKind::ConstantPropGlobal: {
+        std::string demangledName = demangleSymbolAsString(child->getText());
+        if (demangledName.empty()) {
+          Printer << child->getText();
+        } else {
+          Printer << demangledName;
+        }
+        break;
+      }
+      default:
+        print(child, depth + 1);
+    }
+    return;
+  }
+}
+
 void NodePrinter::printSpecializationPrefix(NodePointer node,
                                             StringRef Description,
                                             unsigned depth,
@@ -1506,6 +1485,7 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
     print(Node->getChild(0), depth + 1);
     return nullptr;
   case Node::Kind::OutlinedInitializeWithTake:
+  case Node::Kind::OutlinedInitializeWithTakeNoValueWitness:
     Printer << "outlined init with take of ";
     print(Node->getChild(0), depth + 1);
     return nullptr;
@@ -1665,6 +1645,10 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
     return printEntity(Node, depth, asPrefixContext, TypePrinting::NoType,
                        /*hasName*/ false,
                        "property wrapper backing initializer");
+  case Node::Kind::PropertyWrappedFieldInitAccessor:
+    return printEntity(Node, depth, asPrefixContext, TypePrinting::NoType,
+                       /*hasName*/ false,
+                       "property wrapped field init accessor");
   case Node::Kind::PropertyWrapperInitFromProjectedValue:
     return printEntity(Node, depth, asPrefixContext, TypePrinting::NoType,
                        /*hasName*/ false,
@@ -1914,11 +1898,15 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
   case Node::Kind::FunctionSignatureSpecializationParam:
     printer_unreachable("should be handled in printSpecializationPrefix");
   case Node::Kind::FunctionSignatureSpecializationParamPayload: {
-    std::string demangledName = demangleSymbolAsString(Node->getText());
-    if (demangledName.empty()) {
-      Printer << Node->getText();
-    } else {
-      Printer << demangledName;
+    if (Node->hasText()) {
+      std::string demangledName = demangleSymbolAsString(Node->getText());
+      if (demangledName.empty()) {
+        Printer << Node->getText();
+      } else {
+        Printer << demangledName;
+      }
+    } else if (Node->hasIndex()) {
+      Printer << Node->getIndex();
     }
     return nullptr;
   }
@@ -1990,9 +1978,15 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
     case FunctionSigSpecializationParamKind::ConstantPropKeyPath:
       Printer << "Constant Propagated KeyPath";
       return nullptr;
+    case FunctionSigSpecializationParamKind::ConstantPropStruct:
+      Printer << "Constant Propagated Struct";
+      return nullptr;
     case FunctionSigSpecializationParamKind::ClosureProp:
       Printer << "Closure Propagated";
       return nullptr;
+    case FunctionSigSpecializationParamKind::ClosurePropPreviousArg:
+      Printer << "Same As Argument";
+      return nullptr;
     case FunctionSigSpecializationParamKind::ExistentialToGeneric:
     case FunctionSigSpecializationParamKind::Dead:
     case FunctionSigSpecializationParamKind::OwnedToGuaranteed:
@@ -2393,14 +2387,28 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
       Printer << "merged ";
     }
     return nullptr;
-  case Node::Kind::TypeSymbolicReference:
+  case Node::Kind::TypeSymbolicReference: {
     Printer << "type symbolic reference 0x";
-    Printer.writeHex(Node->getIndex());
+    if (Node->hasRemoteAddress()) {
+      auto ra = Node->getRemoteAddress();
+      Printer.writeHex(ra.first);
+      Printer << " (" << ra.second << ")";
+    } else if (Node->hasIndex()) {
+      Printer.writeHex(Node->getIndex());
+    }
     return nullptr;
-  case Node::Kind::OpaqueTypeDescriptorSymbolicReference:
+  }
+  case Node::Kind::OpaqueTypeDescriptorSymbolicReference: {
     Printer << "opaque type symbolic reference 0x";
-    Printer.writeHex(Node->getIndex());
+    if (Node->hasRemoteAddress()) {
+      auto ra = Node->getRemoteAddress();
+      Printer.writeHex(ra.first);
+      Printer << " (" << ra.second << ")";
+    } else if (Node->hasIndex()) {
+      Printer.writeHex(Node->getIndex());
+    }
     return nullptr;
+  }
   case Node::Kind::DistributedThunk:
     if (!Options.ShortenThunk) {
       Printer << "distributed thunk ";
@@ -2785,6 +2793,12 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
   case Node::Kind::InitAccessor:
     return printAbstractStorage(Node->getFirstChild(), depth, asPrefixContext,
                                 "init");
+  case Node::Kind::BorrowAccessor:
+    return printAbstractStorage(Node->getFirstChild(), depth, asPrefixContext,
+                                "borrow");
+  case Node::Kind::MutateAccessor:
+    return printAbstractStorage(Node->getFirstChild(), depth, asPrefixContext,
+                                "mutate");
   case Node::Kind::Allocator:
     return printEntity(
         Node, depth, asPrefixContext, TypePrinting::FunctionStyle,
@@ -2887,6 +2901,8 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
     Printer << Node->getText() << ' ';
     return nullptr;
   case Node::Kind::ImplParameterSending:
+  case Node::Kind::ImplParameterIsolated:
+  case Node::Kind::ImplParameterImplicitLeading:
     // Skip if text is empty.
     if (Node->getText().empty())
       return nullptr;
@@ -3132,7 +3148,7 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
     Printer << "@isolated(any) ";
     return nullptr;
   case Node::Kind::NonIsolatedCallerFunctionType:
-    Printer << "@execution(caller) ";
+    Printer << "nonisolated(nonsending) ";
     return nullptr;
   case Node::Kind::SendingResultFunctionType:
     Printer << "sending ";
@@ -3275,6 +3291,12 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
     Printer << " to ";
     print(Node->getChild(1), depth + 1);
     return nullptr;
+  case Node::Kind::DependentProtocolConformanceOpaque:
+    Printer << "opaque result conformance ";
+    print(Node->getChild(0), depth + 1);
+    Printer << " of ";
+    print(Node->getChild(1), depth + 1);
+    return nullptr;
   case Node::Kind::ProtocolConformanceRefInTypeModule:
     Printer << "protocol conformance ref (type's module) ";
     printChildren(Node, depth);
@@ -3299,7 +3321,7 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
   case Node::Kind::SugaredInlineArray: {
     Printer << "[";
     print(Node->getChild(0), depth + 1);
-    Printer << " x ";
+    Printer << " of ";
     print(Node->getChild(1), depth + 1);
     Printer << "]";
     return nullptr;
@@ -3567,35 +3589,9 @@ NodePointer NodePrinter::printEntity(NodePointer Entity, unsigned depth,
     }
   }
 
-  if (hasName || !OverwriteName.empty()) {
-    if (!ExtraName.empty() && MultiWordName) {
-      Printer << ExtraName;
-      if (ExtraIndex >= 0)
-        Printer << ExtraIndex;
-
-      Printer << " of ";
-      ExtraName = "";
-      ExtraIndex = -1;
-    }
-    size_t CurrentPos = Printer.getStringRef().size();
-    if (!OverwriteName.empty()) {
-      Printer << OverwriteName;
-    } else {
-      auto Name = Entity->getChild(1);
-      if (Name->getKind() != Node::Kind::PrivateDeclName)
-        print(Name, depth + 1);
+  printFunctionName(hasName, OverwriteName, ExtraName, MultiWordName,
+                    ExtraIndex, Entity, depth);
 
-      if (auto PrivateName = getChildIf(Entity, Node::Kind::PrivateDeclName))
-        print(PrivateName, depth + 1);
-    }
-    if (Printer.getStringRef().size() != CurrentPos && !ExtraName.empty())
-      Printer << '.';
-  }
-  if (!ExtraName.empty()) {
-    Printer << ExtraName;
-    if (ExtraIndex >= 0)
-      Printer << ExtraIndex;
-  }
   if (TypePr != TypePrinting::NoType) {
     NodePointer type = getChildIf(Entity, Node::Kind::Type);
     assert(type && "malformed entity");
@@ -3636,7 +3632,9 @@ NodePointer NodePrinter::printEntity(NodePointer Entity, unsigned depth,
     if (Entity->getKind() == Node::Kind::DefaultArgumentInitializer ||
         Entity->getKind() == Node::Kind::Initializer ||
         Entity->getKind() == Node::Kind::PropertyWrapperBackingInitializer ||
-        Entity->getKind() == Node::Kind::PropertyWrapperInitFromProjectedValue) {
+        Entity->getKind() == Node::Kind::PropertyWrappedFieldInitAccessor ||
+        Entity->getKind() ==
+            Node::Kind::PropertyWrapperInitFromProjectedValue) {
       Printer << " of ";
     } else {
       Printer << " in ";
@@ -3647,6 +3645,43 @@ NodePointer NodePrinter::printEntity(NodePointer Entity, unsigned depth,
   return PostfixContext;
 }
 
+void NodePrinter::printFunctionName(bool hasName,
+                                    llvm::StringRef &OverwriteName,
+                                    llvm::StringRef &ExtraName,
+                                    bool MultiWordName, int &ExtraIndex,
+                                    swift::Demangle::NodePointer Entity,
+                                    unsigned int depth) {
+  if (hasName || !OverwriteName.empty()) {
+    if (!ExtraName.empty() && MultiWordName) {
+      Printer << ExtraName;
+      if (ExtraIndex >= 0)
+        Printer << ExtraIndex;
+
+      Printer << " of ";
+      ExtraName = "";
+      ExtraIndex = -1;
+    }
+    size_t CurrentPos = Printer.getStringRef().size();
+    if (!OverwriteName.empty()) {
+      Printer << OverwriteName;
+    } else {
+      auto Name = Entity->getChild(1);
+      if (Name->getKind() != Node::Kind::PrivateDeclName)
+        print(Name, depth + 1);
+
+      if (auto PrivateName = getChildIf(Entity, Node::Kind::PrivateDeclName))
+        print(PrivateName, depth + 1);
+    }
+    if (Printer.getStringRef().size() != CurrentPos && !ExtraName.empty())
+      Printer << '.';
+  }
+  if (!ExtraName.empty()) {
+    Printer << ExtraName;
+    if (ExtraIndex >= 0)
+      Printer << ExtraIndex;
+  }
+}
+
 void NodePrinter::printEntityType(NodePointer Entity, NodePointer type,
                                   NodePointer genericFunctionTypeList,
                                   unsigned depth) {
@@ -3825,12 +3860,32 @@ std::string Demangle::keyPathSourceString(const char *MangledName,
   return invalid;
 }
 
+/// Converts a demangled node to a string.
+///
+/// \param root The root of the AST to demangle.
+/// \param options The `DemangleOptions` which will be used to create the
+/// NodePrinter.
+///
+/// \return The demangled node as a string.
 std::string Demangle::nodeToString(NodePointer root,
                                    const DemangleOptions &options) {
   if (!root)
     return "";
 
-  return NodePrinter(options).printRoot(root);
+  NodePrinter printer = NodePrinter(options);
+  nodeToString(root, printer);
+  return printer.takeString();
+}
+
+/// Converts a demangled node to a string, which is stored in the `printer`.
+///
+/// \param root The root of the AST to demangle.
+/// \param printer The `NodePrinter` which will be used to print the AST to a
+/// string.
+void Demangle::nodeToString(NodePointer root, NodePrinter &printer) {
+  if (!root)
+    return;
+  printer.printRoot(root);
 }
 
 #endif
diff --git a/lib/Demangling/OldDemangler.cpp b/lib/Demangling/OldDemangler.cpp
index 2a4b5f659b8ed..7acd278a08279 100644
--- a/lib/Demangling/OldDemangler.cpp
+++ b/lib/Demangling/OldDemangler.cpp
@@ -528,7 +528,8 @@ class OldDemangler {
       if (!name || !Mangled.nextIf('_'))
         return false;
       parent->addChild(FUNCSIGSPEC_CREATE_PARAM_KIND(ConstantPropFunction), Factory);
-      parent->addChild(FUNCSIGSPEC_CREATE_PARAM_PAYLOAD(name->getText()), Factory);
+      NodePointer pl = Factory.createNode(Node::Kind::Identifier, name->getText());
+      parent->addChild(pl, Factory);
       return true;
     }
 
@@ -537,7 +538,8 @@ class OldDemangler {
       if (!name || !Mangled.nextIf('_'))
         return false;
       parent->addChild(FUNCSIGSPEC_CREATE_PARAM_KIND(ConstantPropGlobal), Factory);
-      parent->addChild(FUNCSIGSPEC_CREATE_PARAM_PAYLOAD(name->getText()), Factory);
+      NodePointer pl = Factory.createNode(Node::Kind::Identifier, name->getText());
+      parent->addChild(pl, Factory);
       return true;
     }
 
@@ -583,7 +585,8 @@ class OldDemangler {
 
       parent->addChild(FUNCSIGSPEC_CREATE_PARAM_KIND(ConstantPropString), Factory);
       parent->addChild(FUNCSIGSPEC_CREATE_PARAM_PAYLOAD(encodingStr), Factory);
-      parent->addChild(FUNCSIGSPEC_CREATE_PARAM_PAYLOAD(str->getText()), Factory);
+      NodePointer pl = Factory.createNode(Node::Kind::Identifier, str->getText());
+      parent->addChild(pl, Factory);
       return true;
     }
 
diff --git a/lib/Demangling/OldRemangler.cpp b/lib/Demangling/OldRemangler.cpp
index 3a26e908465f4..199e4dac12611 100644
--- a/lib/Demangling/OldRemangler.cpp
+++ b/lib/Demangling/OldRemangler.cpp
@@ -555,6 +555,13 @@ Remangler::mangleDependentProtocolConformanceAssociated(Node *node,
   return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
 }
 
+ManglingError
+Remangler::mangleDependentProtocolConformanceOpaque(Node *node,
+                                                    unsigned depth) {
+  // Dependent conformances aren't in the old mangling
+  return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
+}
+
 ManglingError Remangler::mangleProtocolConformance(Node *node, unsigned depth) {
   // type, protocol name, context
   DEMANGLER_ASSERT(node->getNumChildren() == 3, node);
@@ -1181,6 +1188,11 @@ ManglingError Remangler::manglePropertyWrapperBackingInitializer(
   return mangleSimpleEntity(node, 'I', "P", ctx, depth + 1);
 }
 
+ManglingError Remangler::manglePropertyWrappedFieldInitAccessor(
+    Node *node, EntityContext &ctx, unsigned depth) {
+  return mangleSimpleEntity(node, 'I', "F", ctx, depth + 1);
+}
+
 ManglingError Remangler::manglePropertyWrapperInitFromProjectedValue(
     Node *node, EntityContext &ctx, unsigned depth) {
   return mangleSimpleEntity(node, 'I', "W", ctx, depth + 1);
@@ -1861,7 +1873,17 @@ ManglingError Remangler::mangleImplParameterSending(Node *node,
     Buffer << 'T';
     return ManglingError::Success;
   }
-  return MANGLING_ERROR(ManglingError::InvalidImplParameterSending, node);
+  return MANGLING_ERROR(ManglingError::InvalidImplParameterAttr, node);
+}
+
+ManglingError Remangler::mangleImplParameterIsolated(Node *node,
+                                                    unsigned depth) {
+  return ManglingError::Success;
+}
+
+ManglingError Remangler::mangleImplParameterImplicitLeading(Node *node,
+                                                            unsigned depth) {
+  return ManglingError::Success;
 }
 
 ManglingError Remangler::mangleDynamicSelf(Node *node, unsigned depth) {
@@ -2654,6 +2676,13 @@ ManglingError Remangler::mangleOutlinedDestroy(Node *node, unsigned depth) {
   Buffer << "Wh";
   return mangleSingleChildNode(node, depth + 1);
 }
+
+ManglingError
+Remangler::mangleOutlinedInitializeWithTakeNoValueWitness(Node *node,
+                                                          unsigned depth) {
+  return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
+}
+
 ManglingError Remangler::mangleOutlinedInitializeWithCopyNoValueWitness(Node *node,
                                                                         unsigned depth) {
   return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
@@ -3128,3 +3157,13 @@ ManglingError Remangler::mangleDependentGenericParamValueMarker(Node *node,
                                                                 unsigned depth) {
   return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
 }
+
+ManglingError Remangler::mangleBorrowAccessor(Node *node, EntityContext &ctx,
+                                              unsigned depth) {
+  return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
+}
+
+ManglingError Remangler::mangleMutateAccessor(Node *node, EntityContext &ctx,
+                                              unsigned depth) {
+  return MANGLING_ERROR(ManglingError::UnsupportedNodeKind, node);
+}
diff --git a/lib/Demangling/Remangler.cpp b/lib/Demangling/Remangler.cpp
index 4a29fd664911b..f9a339eee25e8 100644
--- a/lib/Demangling/Remangler.cpp
+++ b/lib/Demangling/Remangler.cpp
@@ -632,6 +632,7 @@ ManglingError Remangler::mangleGenericArgs(Node *node, char &Separator,
     case Node::Kind::DefaultArgumentInitializer:
     case Node::Kind::Initializer:
     case Node::Kind::PropertyWrapperBackingInitializer:
+    case Node::Kind::PropertyWrappedFieldInitAccessor:
     case Node::Kind::PropertyWrapperInitFromProjectedValue:
     case Node::Kind::Static:
       if (!fullSubstitutionMap)
@@ -1500,37 +1501,18 @@ ManglingError Remangler::mangleFunction(Node *node, unsigned depth) {
 ManglingError Remangler::mangleFunctionSignatureSpecialization(Node *node,
                                                                unsigned depth) {
   for (NodePointer Param : *node) {
-    if (Param->getKind() == Node::Kind::FunctionSignatureSpecializationParam &&
-        Param->getNumChildren() > 0) {
-      Node *KindNd = Param->getChild(0);
-      switch (FunctionSigSpecializationParamKind(KindNd->getIndex())) {
-        case FunctionSigSpecializationParamKind::ConstantPropFunction:
-        case FunctionSigSpecializationParamKind::ConstantPropGlobal:
-          RETURN_IF_ERROR(mangleIdentifier(Param->getChild(1), depth + 1));
-          break;
-        case FunctionSigSpecializationParamKind::ConstantPropString: {
-          NodePointer TextNd = Param->getChild(2);
-          StringRef Text = TextNd->getText();
-          if (!Text.empty() && (isDigit(Text[0]) || Text[0] == '_')) {
-            std::string Buffer = "_";
-            Buffer.append(Text.data(), Text.size());
-            TextNd = Factory.createNode(Node::Kind::Identifier, Buffer);
-          }
-          RETURN_IF_ERROR(mangleIdentifier(TextNd, depth + 1));
-          break;
-        }
-        case FunctionSigSpecializationParamKind::ClosureProp:
-        case FunctionSigSpecializationParamKind::ConstantPropKeyPath:
-          RETURN_IF_ERROR(mangleIdentifier(Param->getChild(1), depth + 1));
-          for (unsigned i = 2, e = Param->getNumChildren(); i != e; ++i) {
-            RETURN_IF_ERROR(mangleType(Param->getChild(i), depth + 1));
-          }
-          break;
-        default:
-          break;
+    if (Param->getKind() != Node::Kind::FunctionSignatureSpecializationParam)
+      continue;
+
+    for (NodePointer paramChild : *Param) {
+      if (paramChild->getKind() == Node::Kind::FunctionSignatureSpecializationParamKind ||
+          paramChild->getKind() == Node::Kind::FunctionSignatureSpecializationParamPayload) {
+        continue;
       }
+      RETURN_IF_ERROR(mangle(paramChild, depth + 1));
     }
   }
+
   Buffer << "Tf";
   bool returnValMangled = false;
   for (NodePointer Child : *node) {
@@ -1567,26 +1549,37 @@ Remangler::mangleFunctionSignatureSpecializationParam(Node *node,
 
   // The first child is always a kind that specifies the type of param that we
   // have.
-  Node *KindNd = node->getChild(0);
-  unsigned kindValue = KindNd->getIndex();
-  auto kind = FunctionSigSpecializationParamKind(kindValue);
+  const char *constPropPrefix = "p";
+
+  size_t idx = 0, end = node->getNumChildren();
+  while (idx < end) {
+    Node *kindNd = node->getChild(idx++);
+    if (kindNd->getKind() != Node::Kind::FunctionSignatureSpecializationParamKind)
+      continue;
+  
+    unsigned kindValue = kindNd->getIndex();
 
-  switch (kind) {
+    switch (FunctionSigSpecializationParamKind(kindValue)) {
     case FunctionSigSpecializationParamKind::ConstantPropFunction:
-      Buffer << "pf";
+      Buffer << constPropPrefix << "f";
+      constPropPrefix = "";
       break;
     case FunctionSigSpecializationParamKind::ConstantPropGlobal:
-      Buffer << "pg";
+      Buffer << constPropPrefix << "g";
+      constPropPrefix = "";
       break;
     case FunctionSigSpecializationParamKind::ConstantPropInteger:
-      Buffer << "pi" << node->getChild(1)->getText();
+      Buffer << constPropPrefix << "i" << node->getChild(idx++)->getText();
+      constPropPrefix = "";
       break;
     case FunctionSigSpecializationParamKind::ConstantPropFloat:
-      Buffer << "pd" << node->getChild(1)->getText();
+      Buffer << constPropPrefix << "d" << node->getChild(idx++)->getText();
+      constPropPrefix = "";
       break;
     case FunctionSigSpecializationParamKind::ConstantPropString: {
-      Buffer << "ps";
-      StringRef encodingStr = node->getChild(1)->getText();
+      Buffer << constPropPrefix << "s";
+      constPropPrefix = "";
+      StringRef encodingStr = node->getChild(idx++)->getText();
       if (encodingStr == "u8") {
         Buffer << 'b';
       } else if (encodingStr == "u16") {
@@ -1599,11 +1592,19 @@ Remangler::mangleFunctionSignatureSpecializationParam(Node *node,
       break;
     }
     case FunctionSigSpecializationParamKind::ConstantPropKeyPath:
-      Buffer << "pk";
+      Buffer << constPropPrefix << "k";
+      constPropPrefix = "";
+      break;
+    case FunctionSigSpecializationParamKind::ConstantPropStruct:
+      Buffer << constPropPrefix << "S";
+      constPropPrefix = "";
       break;
     case FunctionSigSpecializationParamKind::ClosureProp:
       Buffer << 'c';
       break;
+    case FunctionSigSpecializationParamKind::ClosurePropPreviousArg:
+      Buffer << 'C' << node->getChild(idx++)->getIndex();
+      break;
     case FunctionSigSpecializationParamKind::BoxToValue:
       Buffer << 'i';
       break;
@@ -1649,6 +1650,7 @@ Remangler::mangleFunctionSignatureSpecializationParam(Node *node,
       if (kindValue & unsigned(FunctionSigSpecializationParamKind::SROA))
         Buffer << 'X';
       break;
+    }
   }
 
   return ManglingError::Success;
@@ -1953,7 +1955,31 @@ ManglingError Remangler::mangleImplParameterSending(Node *node,
   char diffChar =
       llvm::StringSwitch<char>(node->getText()).Case("sending", 'T').Default(0);
   if (!diffChar)
-    return MANGLING_ERROR(ManglingError::InvalidImplParameterSending, node);
+    return MANGLING_ERROR(ManglingError::InvalidImplParameterAttr, node);
+  Buffer << diffChar;
+
+  return ManglingError::Success;
+}
+
+ManglingError Remangler::mangleImplParameterIsolated(Node *node,
+                                                     unsigned depth) {
+  DEMANGLER_ASSERT(node->hasText(), node);
+  char diffChar =
+      llvm::StringSwitch<char>(node->getText()).Case("isolated", 'I').Default(0);
+  if (!diffChar)
+    return MANGLING_ERROR(ManglingError::InvalidImplParameterAttr, node);
+  Buffer << diffChar;
+
+  return ManglingError::Success;
+}
+
+ManglingError Remangler::mangleImplParameterImplicitLeading(Node *node,
+                                                            unsigned depth) {
+  DEMANGLER_ASSERT(node->hasText(), node);
+  char diffChar =
+      llvm::StringSwitch<char>(node->getText()).Case("sil_implicit_leading_param", 'L').Default(0);
+  if (!diffChar)
+    return MANGLING_ERROR(ManglingError::InvalidImplParameterAttr, node);
   Buffer << diffChar;
 
   return ManglingError::Success;
@@ -2030,10 +2056,7 @@ ManglingError Remangler::mangleImplFunctionType(Node *node, unsigned depth) {
     case Node::Kind::ImplYield:
     case Node::Kind::ImplErrorResult:
       // Mangle type. Type should be the last child.
-      DEMANGLER_ASSERT(Child->getNumChildren() == 2 ||
-                           Child->getNumChildren() == 3 ||
-                           Child->getNumChildren() == 4,
-                       node);
+      DEMANGLER_ASSERT(Child->getNumChildren() >= 2, Child);
       RETURN_IF_ERROR(mangle(Child->getLastChild(), depth + 1));
       break;
     case Node::Kind::DependentPseudogenericSignature:
@@ -2168,15 +2191,32 @@ ManglingError Remangler::mangleImplFunctionType(Node *node, unsigned depth) {
                                Child->getFirstChild());
         }
         Buffer << ConvCh;
-        // Mangle parameter differentiability, if it exists.
-        if (Child->getNumChildren() == 3) {
-          RETURN_IF_ERROR(mangleImplParameterResultDifferentiability(
-              Child->getChild(1), depth + 1));
-        } else if (Child->getNumChildren() == 4) {
-          RETURN_IF_ERROR(mangleImplParameterResultDifferentiability(
-              Child->getChild(1), depth + 1));
-          RETURN_IF_ERROR(
-              mangleImplParameterSending(Child->getChild(2), depth + 1));
+
+        for (unsigned i = 1; i < Child->getNumChildren() - 1; ++i) {
+          auto *Grandchild = Child->getChild(i);
+          switch (Grandchild->getKind()) {
+          case Node::Kind::ImplParameterResultDifferentiability:
+            RETURN_IF_ERROR(mangleImplParameterResultDifferentiability(
+              Grandchild, depth + 1));
+            break;
+          case Node::Kind::ImplParameterSending:
+            RETURN_IF_ERROR(mangleImplParameterSending(
+              Grandchild, depth + 1));
+            break;
+          case Node::Kind::ImplParameterIsolated:
+            RETURN_IF_ERROR(mangleImplParameterIsolated(
+              Grandchild, depth + 1));
+            break;
+          case Node::Kind::ImplParameterImplicitLeading:
+            RETURN_IF_ERROR(mangleImplParameterImplicitLeading(
+              Grandchild, depth + 1));
+            break;
+          default:
+            Child->dump();
+            abort();
+            return MANGLING_ERROR(ManglingError::InvalidImplParameterAttr,
+                                  Grandchild);
+          }
         }
         break;
       }
@@ -2316,6 +2356,13 @@ Remangler::manglePropertyWrapperBackingInitializer(Node *node, unsigned depth) {
   return ManglingError::Success;
 }
 
+ManglingError
+Remangler::manglePropertyWrappedFieldInitAccessor(Node *node, unsigned depth) {
+  RETURN_IF_ERROR(mangleChildNodes(node, depth + 1));
+  Buffer << "fF";
+  return ManglingError::Success;
+}
+
 ManglingError
 Remangler::manglePropertyWrapperInitFromProjectedValue(Node *node,
                                                        unsigned depth) {
@@ -2777,6 +2824,16 @@ ManglingError Remangler::mangleDependentConformanceIndex(Node *node,
   return ManglingError::Success;
 }
 
+ManglingError Remangler::mangleDependentProtocolConformanceOpaque(Node *node,
+                                                                  unsigned depth) {
+  DEMANGLER_ASSERT(node->getKind() == Node::Kind::DependentProtocolConformanceOpaque,
+                   node);
+  RETURN_IF_ERROR(mangleAnyProtocolConformance(node->getChild(0), depth + 1));
+  RETURN_IF_ERROR(mangleType(node->getChild(1), depth + 1));
+  Buffer << "HO";
+  return ManglingError::Success;
+}
+
 ManglingError Remangler::mangleAnyProtocolConformance(Node *node,
                                                       unsigned depth) {
   switch (node->getKind()) {
@@ -2790,6 +2847,8 @@ ManglingError Remangler::mangleAnyProtocolConformance(Node *node,
     return mangleDependentProtocolConformanceInherited(node, depth + 1);
   case Node::Kind::DependentProtocolConformanceAssociated:
     return mangleDependentProtocolConformanceAssociated(node, depth + 1);
+  case Node::Kind::DependentProtocolConformanceOpaque:
+    return mangleDependentProtocolConformanceOpaque(node, depth + 1);
   default:
     // Should this really succeed?!
     return ManglingError::Success;
@@ -3564,6 +3623,14 @@ ManglingError Remangler::mangleOutlinedInitializeWithTake(Node *node,
   return ManglingError::Success;
 }
 
+ManglingError
+Remangler::mangleOutlinedInitializeWithTakeNoValueWitness(Node *node,
+                                                          unsigned depth) {
+  RETURN_IF_ERROR(mangleChildNodes(node, depth + 1));
+  Buffer << "WOB";
+  return ManglingError::Success;
+}
+
 ManglingError Remangler::mangleOutlinedInitializeWithCopy(Node *node,
                                                           unsigned depth) {
   RETURN_IF_ERROR(mangleChildNodes(node, depth + 1));
@@ -4063,6 +4130,14 @@ ManglingError Remangler::mangleDependentGenericParamValueMarker(Node *node,
   return ManglingError::Success;
 }
 
+ManglingError Remangler::mangleBorrowAccessor(Node *node, unsigned depth) {
+  return mangleAbstractStorage(node->getFirstChild(), "b", depth + 1);
+}
+
+ManglingError Remangler::mangleMutateAccessor(Node *node, unsigned depth) {
+  return mangleAbstractStorage(node->getFirstChild(), "z", depth + 1);
+}
+
 } // anonymous namespace
 
 /// The top-level interface to the remangler.
@@ -4139,6 +4214,7 @@ bool Demangle::isSpecialized(Node *node) {
     case Node::Kind::ImplicitClosure:
     case Node::Kind::Initializer:
     case Node::Kind::PropertyWrapperBackingInitializer:
+    case Node::Kind::PropertyWrappedFieldInitAccessor:
     case Node::Kind::PropertyWrapperInitFromProjectedValue:
     case Node::Kind::DefaultArgumentInitializer:
     case Node::Kind::Getter:
@@ -4184,6 +4260,7 @@ ManglingErrorOr<NodePointer> Demangle::getUnspecialized(Node *node,
     case Node::Kind::ImplicitClosure:
     case Node::Kind::Initializer:
     case Node::Kind::PropertyWrapperBackingInitializer:
+    case Node::Kind::PropertyWrappedFieldInitAccessor:
     case Node::Kind::PropertyWrapperInitFromProjectedValue:
     case Node::Kind::DefaultArgumentInitializer:
     case Node::Kind::Static:
diff --git a/lib/Demangling/RemanglerBase.h b/lib/Demangling/RemanglerBase.h
index 7a6a4fe9feefc..2ed698e4d2a91 100644
--- a/lib/Demangling/RemanglerBase.h
+++ b/lib/Demangling/RemanglerBase.h
@@ -1,4 +1,4 @@
-//===--- Demangler.h - String to Node-Tree Demangling -----------*- C++ -*-===//
+//===--- RemanglerBase.h - String to Node-Tree Demangling -------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -19,6 +19,7 @@
 
 #include "swift/Demangling/Demangler.h"
 #include "swift/Demangling/NamespaceMacros.h"
+#include "llvm/ADT/PointerIntPair.h"
 #include <unordered_map>
 
 using namespace swift::Demangle;
@@ -37,14 +38,19 @@ SWIFT_BEGIN_INLINE_NAMESPACE
 
 // An entry in the remangler's substitution map.
 class SubstitutionEntry {
-  Node *TheNode = nullptr;
+  llvm::PointerIntPair<Node *, 1, bool> NodeAndTreatAsIdentifier;
   size_t StoredHash = 0;
-  bool treatAsIdentifier = false;
+
+  Node *getNode() const { return NodeAndTreatAsIdentifier.getPointer(); }
+
+  bool getTreatAsIdentifier() const {
+    return NodeAndTreatAsIdentifier.getInt();
+  }
 
 public:
   void setNode(Node *node, bool treatAsIdentifier, size_t hash) {
-    this->treatAsIdentifier = treatAsIdentifier;
-    TheNode = node;
+    NodeAndTreatAsIdentifier.setPointer(node);
+    NodeAndTreatAsIdentifier.setInt(treatAsIdentifier);
     StoredHash = hash;
   }
 
@@ -54,10 +60,10 @@ class SubstitutionEntry {
     }
   };
 
-  bool isEmpty() const { return !TheNode; }
+  bool isEmpty() const { return !getNode(); }
 
   bool matches(Node *node, bool treatAsIdentifier) const {
-    return node == TheNode && treatAsIdentifier == this->treatAsIdentifier;
+    return node == getNode() && treatAsIdentifier == getTreatAsIdentifier();
   }
 
   size_t hash() const { return StoredHash; }
@@ -67,12 +73,12 @@ class SubstitutionEntry {
                          const SubstitutionEntry &rhs) {
     if (lhs.StoredHash != rhs.StoredHash)
       return false;
-    if (lhs.treatAsIdentifier != rhs.treatAsIdentifier)
+    if (lhs.getTreatAsIdentifier() != rhs.getTreatAsIdentifier())
       return false;
-    if (lhs.treatAsIdentifier) {
-      return identifierEquals(lhs.TheNode, rhs.TheNode);
+    if (lhs.getTreatAsIdentifier()) {
+      return identifierEquals(lhs.getNode(), rhs.getNode());
     }
-    return lhs.deepEquals(lhs.TheNode, rhs.TheNode);
+    return lhs.deepEquals(lhs.getNode(), rhs.getNode());
   }
 
   static bool identifierEquals(Node *lhs, Node *rhs);
diff --git a/lib/DependencyScan/DependencyScanJSON.cpp b/lib/DependencyScan/DependencyScanJSON.cpp
index 4df34e396903f..fd609e1d19798 100644
--- a/lib/DependencyScan/DependencyScanJSON.cpp
+++ b/lib/DependencyScan/DependencyScanJSON.cpp
@@ -77,6 +77,11 @@ void writeJSONValue(llvm::raw_ostream &out, bool value, unsigned indentLevel) {
   out.write_escaped(value ? "true" : "false");
 }
 
+/// Write a boolean value as JSON.
+void writeJSONValue(llvm::raw_ostream &out, uint32_t value, unsigned indentLevel) {
+  out.write_escaped(std::to_string(value));
+}
+
 /// Write a JSON array.
 template <typename T>
 void writeJSONValue(llvm::raw_ostream &out, ArrayRef<T> values,
@@ -129,7 +134,6 @@ void writeEncodedModuleIdJSONValue(llvm::raw_ostream &out,
   out << "{\n";
   static const std::string textualPrefix("swiftTextual");
   static const std::string binaryPrefix("swiftBinary");
-  static const std::string placeholderPrefix("swiftPlaceholder");
   static const std::string clangPrefix("clang");
   std::string valueStr = get_C_string(value);
   std::string moduleKind;
@@ -141,10 +145,6 @@ void writeEncodedModuleIdJSONValue(llvm::raw_ostream &out,
     // FIXME: rename to be consistent in the clients (swift-driver)
     moduleKind = "swiftPrebuiltExternal";
     moduleName = valueStr.substr(binaryPrefix.size() + 1);
-  } else if (!valueStr.compare(0, placeholderPrefix.size(),
-                               placeholderPrefix)) {
-    moduleKind = "swiftPlaceholder";
-    moduleName = valueStr.substr(placeholderPrefix.size() + 1);
   } else {
     moduleKind = "clang";
     moduleName = valueStr.substr(clangPrefix.size() + 1);
@@ -226,6 +226,94 @@ void writeLinkLibraries(llvm::raw_ostream &out,
   out << "\n";
 }
 
+void writeImportInfos(llvm::raw_ostream &out,
+                      const swiftscan_import_info_set_t *imports,
+                      bool optional, unsigned indentLevel,
+                      bool trailingComma) {
+  out.indent(indentLevel * 2);
+  if (optional)
+    out << "\"optionalImports\": ";
+  else
+    out << "\"imports\": ";
+  out << "[\n";
+
+  for (size_t i = 0; i < imports->count; ++i) {
+    const auto &iInfo = *imports->imports[i];
+    out.indent((indentLevel + 1) * 2);
+    out << "{\n";
+    auto entryIndentLevel = ((indentLevel + 2) * 2);
+    out.indent(entryIndentLevel);
+    out << "\"identifier\": ";
+    writeJSONValue(out, iInfo.import_identifier, indentLevel);
+    out << ",\n";
+    out.indent(entryIndentLevel);
+    out << "\"accessLevel\": ";
+    switch (iInfo.access_level) {
+      case SWIFTSCAN_ACCESS_LEVEL_PRIVATE:
+        writeJSONValue(out, StringRef("private"), entryIndentLevel);
+        break;
+      case SWIFTSCAN_ACCESS_LEVEL_FILEPRIVATE:
+        writeJSONValue(out, StringRef("fileprivate"), entryIndentLevel);
+        break;
+      case SWIFTSCAN_ACCESS_LEVEL_INTERNAL:
+        writeJSONValue(out, StringRef("internal"), entryIndentLevel);
+        break;
+      case SWIFTSCAN_ACCESS_LEVEL_PACKAGE:
+        writeJSONValue(out, StringRef("package"), entryIndentLevel);
+        break;
+      case SWIFTSCAN_ACCESS_LEVEL_PUBLIC:
+        writeJSONValue(out, StringRef("public"), entryIndentLevel);
+        break;
+    }
+
+    if (iInfo.source_locations->count) {
+      out << ",\n";
+      out.indent(entryIndentLevel);
+      out << "\"importLocations\": ";
+      out << "[\n";
+      auto slIndentLevel = ((entryIndentLevel + 4));
+      for (size_t i = 0; i < iInfo.source_locations->count; ++i) {
+        out.indent(entryIndentLevel + 2);
+        out << "{\n";
+        const auto &sl = *iInfo.source_locations->source_locations[i];
+        out.indent(slIndentLevel);
+        out << "\"bufferIdentifier\": ";
+        writeJSONValue(out, sl.buffer_identifier, indentLevel);
+        out << ",\n";
+        out.indent(slIndentLevel);
+        out << "\"linuNumber\": ";
+        writeJSONValue(out, sl.line_number, indentLevel);
+        out << ",\n";
+        out.indent(slIndentLevel);
+        out << "\"columnNumber\": ";
+        writeJSONValue(out, sl.column_number, indentLevel);
+        out << "\n";
+        out.indent(entryIndentLevel + 2);
+        out << "}";
+        if (i != iInfo.source_locations->count - 1)
+          out << ",";
+        out << "\n";
+      }
+      out.indent(entryIndentLevel);
+      out << "]\n";
+    } else {
+      out << "\n";
+    }
+    out.indent((indentLevel + 1) * 2);
+    out << "}";
+    if (i != imports->count - 1)
+      out << ",";
+    out << "\n";
+  }
+
+  out.indent(indentLevel * 2);
+  out << "]";
+
+  if (trailingComma)
+    out << ",";
+  out << "\n";
+}
+
 static void
 writeMacroDependencies(llvm::raw_ostream &out,
                        const swiftscan_macro_dependency_set_t *macro_deps,
@@ -243,15 +331,15 @@ writeMacroDependencies(llvm::raw_ostream &out,
     auto entryIndentLevel = ((indentLevel + 2) * 2);
     out.indent(entryIndentLevel);
     out << "\"moduleName\": ";
-    writeJSONValue(out, macroInfo.moduleName, indentLevel);
+    writeJSONValue(out, macroInfo.module_name, indentLevel);
     out << ",\n";
     out.indent(entryIndentLevel);
     out << "\"libraryPath\": ";
-    writeJSONValue(out, macroInfo.libraryPath, entryIndentLevel);
+    writeJSONValue(out, macroInfo.library_path, entryIndentLevel);
     out << ",\n";
     out.indent(entryIndentLevel);
     out << "\"executablePath\": ";
-    writeJSONValue(out, macroInfo.executablePath, entryIndentLevel);
+    writeJSONValue(out, macroInfo.executable_path, entryIndentLevel);
     out << "\n";
     out.indent((indentLevel + 1) * 2);
     out << "}";
@@ -276,13 +364,6 @@ getAsTextualDependencyModule(swiftscan_module_details_t details) {
   return nullptr;
 }
 
-static const swiftscan_swift_placeholder_details_t *
-getAsPlaceholderDependencyModule(swiftscan_module_details_t details) {
-  if (details->kind == SWIFTSCAN_DEPENDENCY_INFO_SWIFT_PLACEHOLDER)
-    return &details->swift_placeholder_details;
-  return nullptr;
-}
-
 static const swiftscan_swift_binary_details_t *
 getAsBinaryDependencyModule(swiftscan_module_details_t details) {
   if (details->kind == SWIFTSCAN_DEPENDENCY_INFO_SWIFT_BINARY)
@@ -329,8 +410,6 @@ void writeJSON(llvm::raw_ostream &out,
     out << ",\n";
     out.indent(2 * 2);
     out << "{\n";
-    auto swiftPlaceholderDeps =
-        getAsPlaceholderDependencyModule(moduleInfo.details);
     auto swiftTextualDeps = getAsTextualDependencyModule(moduleInfo.details);
     auto swiftBinaryDeps = getAsBinaryDependencyModule(moduleInfo.details);
     auto clangDeps = getAsClangDependencyModule(moduleInfo.details);
@@ -343,9 +422,7 @@ void writeJSON(llvm::raw_ostream &out,
         std::string(get_C_string(moduleInfo.module_name));
     std::string moduleName =
         moduleKindAndName.substr(moduleKindAndName.find(":") + 1);
-    if (swiftPlaceholderDeps)
-      modulePath = get_C_string(swiftPlaceholderDeps->compiled_module_path);
-    else if (swiftBinaryDeps)
+    if (swiftBinaryDeps)
       modulePath = get_C_string(swiftBinaryDeps->compiled_module_path);
     else if (clangDeps || swiftTextualDeps)
       modulePath = get_C_string(moduleInfo.module_path);
@@ -368,6 +445,10 @@ void writeJSON(llvm::raw_ostream &out,
                         /*trailingComma=*/true);
       writeLinkLibraries(out, moduleInfo.link_libraries,
                          3, /*trailingComma=*/true);
+      writeImportInfos(out, moduleInfo.imports, /*optional*/ false,
+                       3, /*trailingComma=*/true);
+      writeImportInfos(out, moduleInfo.optional_imports, /*optional*/ true,
+                       3, /*trailingComma=*/true);
     }
     // Swift and Clang-specific details.
     out.indent(3 * 2);
@@ -424,6 +505,9 @@ void writeJSON(llvm::raw_ostream &out,
       bool hasOverlayDependencies =
           swiftTextualDeps->swift_overlay_module_dependencies &&
           swiftTextualDeps->swift_overlay_module_dependencies->count > 0;
+      bool hasSourceImportedDependencies =
+          swiftTextualDeps->source_import_module_dependencies &&
+          swiftTextualDeps->source_import_module_dependencies->count > 0;
       bool commaAfterBridgingHeaderPath = hasOverlayDependencies;
       bool commaAfterFramework =
           hasBridgingHeader || commaAfterBridgingHeaderPath;
@@ -448,6 +532,11 @@ void writeJSON(llvm::raw_ostream &out,
                            /*trailingComma=*/true);
       writeMacroDependencies(out, swiftTextualDeps->macro_dependencies, 5,
                              /*trailingComma=*/true);
+      if (hasSourceImportedDependencies) {
+        writeDependencies(out, swiftTextualDeps->source_import_module_dependencies,
+                          "sourceImportedDependencies", 5,
+                          /*trailingComma=*/true);
+      }
       writeJSONSingleField(out, "isFramework", swiftTextualDeps->is_framework,
                            5, commaAfterFramework);
       /// Bridging header and its source file dependencies, if any.
@@ -491,25 +580,6 @@ void writeJSON(llvm::raw_ostream &out,
                           "swiftOverlayDependencies", 5,
                           /*trailingComma=*/false);
       }
-    } else if (swiftPlaceholderDeps) {
-      out << "\"swiftPlaceholder\": {\n";
-
-      // Module doc file
-      if (swiftPlaceholderDeps->module_doc_path.data &&
-          get_C_string(swiftPlaceholderDeps->module_doc_path)[0] != '\0')
-        writeJSONSingleField(out, "moduleDocPath",
-                             swiftPlaceholderDeps->module_doc_path,
-                             /*indentLevel=*/5,
-                             /*trailingComma=*/true);
-
-      // Module Source Info file
-      if (swiftPlaceholderDeps->module_source_info_path.data &&
-          get_C_string(swiftPlaceholderDeps->module_source_info_path)[0] !=
-              '\0')
-        writeJSONSingleField(out, "moduleSourceInfoPath",
-                             swiftPlaceholderDeps->module_source_info_path,
-                             /*indentLevel=*/5,
-                             /*trailingComma=*/false);
     } else if (swiftBinaryDeps) {
       bool hasOverlayDependencies =
         swiftBinaryDeps->swift_overlay_module_dependencies &&
diff --git a/lib/DependencyScan/DependencyScanningTool.cpp b/lib/DependencyScan/DependencyScanningTool.cpp
index 982cf77c7d9fd..6a307bf40ff75 100644
--- a/lib/DependencyScan/DependencyScanningTool.cpp
+++ b/lib/DependencyScan/DependencyScanningTool.cpp
@@ -15,6 +15,7 @@
 #include "swift/Basic/LLVMInitialize.h"
 #include "swift/Basic/TargetInfo.h"
 #include "swift/Basic/ColorUtils.h"
+#include "swift/Basic/Defer.h"
 #include "swift/DependencyScan/DependencyScanningTool.h"
 #include "swift/DependencyScan/DependencyScanImpl.h"
 #include "swift/DependencyScan/SerializedModuleDependencyCacheFormat.h"
@@ -64,15 +65,16 @@ llvm::ErrorOr<swiftscan_string_ref_t> getTargetInfo(ArrayRef<const char *> Comma
   return c_string_utils::create_clone(ResultStr.c_str());
 }
 
-void DependencyScanDiagnosticCollector::handleDiagnostic(SourceManager &SM,
+void ThreadSafeDiagnosticCollector::handleDiagnostic(SourceManager &SM,
                       const DiagnosticInfo &Info) {
+  llvm::sys::SmartScopedLock<true> Lock(DiagnosticConsumerStateLock);
   addDiagnostic(SM, Info);
   for (auto ChildInfo : Info.ChildDiagnosticInfo) {
     addDiagnostic(SM, *ChildInfo);
   }
 }
 
-void DependencyScanDiagnosticCollector::addDiagnostic(
+void DepScanInMemoryDiagnosticCollector::addDiagnostic(
     SourceManager &SM, const DiagnosticInfo &Info) {
   // Determine what kind of diagnostic we're emitting.
   llvm::SourceMgr::DiagKind SMKind;
@@ -129,22 +131,16 @@ void DependencyScanDiagnosticCollector::addDiagnostic(
   }
 }
 
-void LockingDependencyScanDiagnosticCollector::addDiagnostic(
-    SourceManager &SM, const DiagnosticInfo &Info) {
-  llvm::sys::SmartScopedLock<true> Lock(ScanningDiagnosticConsumerStateLock);
-  DependencyScanDiagnosticCollector::addDiagnostic(SM, Info);
-}
-
 swiftscan_diagnostic_set_t *mapCollectedDiagnosticsForOutput(
-    const DependencyScanDiagnosticCollector *diagnosticCollector) {
-  auto collectedDiagnostics = diagnosticCollector->getDiagnostics();
-  auto numDiagnostics = collectedDiagnostics.size();
+    ArrayRef<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+        diagnostics) {
+  auto numDiagnostics = diagnostics.size();
   swiftscan_diagnostic_set_t *diagnosticOutput = new swiftscan_diagnostic_set_t;
   diagnosticOutput->count = numDiagnostics;
   diagnosticOutput->diagnostics =
       new swiftscan_diagnostic_info_t[numDiagnostics];
   for (size_t i = 0; i < numDiagnostics; ++i) {
-    const auto &Diagnostic = collectedDiagnostics[i];
+    const auto &Diagnostic = diagnostics[i];
     swiftscan_diagnostic_info_s *diagnosticInfo =
         new swiftscan_diagnostic_info_s;
     diagnosticInfo->message =
@@ -188,7 +184,8 @@ swiftscan_diagnostic_set_t *mapCollectedDiagnosticsForOutput(
 // module dependnecies but captures the diagnostics emitted during the attempted
 // scan query.
 static swiftscan_dependency_graph_t generateHollowDiagnosticOutput(
-    const DependencyScanDiagnosticCollector &ScanDiagnosticConsumer) {
+    ArrayRef<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+        diagnostics) {
   // Create a dependency graph instance
   swiftscan_dependency_graph_t hollowResult = new swiftscan_dependency_graph_s;
 
@@ -222,6 +219,7 @@ static swiftscan_dependency_graph_t generateHollowDiagnosticOutput(
                                           c_string_utils::create_empty_set(),
                                           c_string_utils::create_empty_set(),
                                           c_string_utils::create_empty_set(),
+                                          c_string_utils::create_empty_set(),
                                           c_string_utils::create_null(),
                                           false,
                                           false,
@@ -241,9 +239,16 @@ static swiftscan_dependency_graph_t generateHollowDiagnosticOutput(
   hollowLinkLibrarySet->link_libraries = nullptr;
   hollowMainModuleInfo->link_libraries = hollowLinkLibrarySet;
 
+  // Empty Import set
+  swiftscan_import_info_set_t *hollowImportInfoSet =
+      new swiftscan_import_info_set_t;
+  hollowImportInfoSet->count = 0;
+  hollowImportInfoSet->imports = nullptr;
+  hollowMainModuleInfo->imports = hollowImportInfoSet;
+
   // Populate the diagnostic info
   hollowResult->diagnostics =
-      mapCollectedDiagnosticsForOutput(&ScanDiagnosticConsumer);
+      mapCollectedDiagnosticsForOutput(diagnostics);
   return hollowResult;
 }
 
@@ -251,49 +256,46 @@ static swiftscan_dependency_graph_t generateHollowDiagnosticOutput(
 // imports but captures the diagnostics emitted during the attempted
 // scan query.
 static swiftscan_import_set_t generateHollowDiagnosticOutputImportSet(
-    const DependencyScanDiagnosticCollector &ScanDiagnosticConsumer) {
+    ArrayRef<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+        diagnostics) {
   // Create an dependency graph instance
   swiftscan_import_set_t hollowResult = new swiftscan_import_set_s;
   hollowResult->imports = c_string_utils::create_empty_set();
   hollowResult->diagnostics =
-      mapCollectedDiagnosticsForOutput(&ScanDiagnosticConsumer);
+    mapCollectedDiagnosticsForOutput(diagnostics);
   return hollowResult;
 }
 
 DependencyScanningTool::DependencyScanningTool()
     : ScanningService(std::make_unique<SwiftDependencyScanningService>()),
-      CDC(), Alloc(), Saver(Alloc) {}
+      Alloc(), Saver(Alloc) {}
 
 llvm::ErrorOr<swiftscan_dependency_graph_t>
-DependencyScanningTool::getDependencies(
-    ArrayRef<const char *> Command,
-    const llvm::StringSet<> &PlaceholderModules,
-    StringRef WorkingDirectory) {
-  // There may be errors as early as in instance initialization, so we must ensure
-  // we can catch those.
-  auto ScanDiagnosticConsumer = std::make_shared<DependencyScanDiagnosticCollector>();
+DependencyScanningTool::getDependencies(ArrayRef<const char *> Command,
+                                        StringRef WorkingDirectory) {
+  // Diagnostics which may get collected during scanning instance
+  // initialization
+  std::vector<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+      InitializationDiagnostics;
 
   // The primary instance used to scan the query Swift source-code
-  auto QueryContextOrErr = initCompilerInstanceForScan(Command,
-                                                       WorkingDirectory,
-                                                       ScanDiagnosticConsumer);
-  if (QueryContextOrErr.getError())
-    return generateHollowDiagnosticOutput(*ScanDiagnosticConsumer);
-
-  auto QueryContext = std::move(*QueryContextOrErr);
+  auto QueryContext = createScanQueryContext(Command, WorkingDirectory,
+                                             InitializationDiagnostics);
+  if (QueryContext.getError())
+    return generateHollowDiagnosticOutput(InitializationDiagnostics);
+  auto ScanInstance = QueryContext->ScanInstance.get();
 
   // Local scan cache instance, wrapping the shared global cache.
   ModuleDependenciesCache cache(
-      *ScanningService, QueryContext.ScanInstance->getMainModule()->getNameStr().str(),
-      QueryContext.ScanInstance->getInvocation().getFrontendOptions().ExplicitModulesOutputPath,
-      QueryContext.ScanInstance->getInvocation().getFrontendOptions().ExplicitSDKModulesOutputPath,
-      QueryContext.ScanInstance->getInvocation().getModuleScanningHash());
+      ScanInstance->getMainModule()->getNameStr().str(),
+      ScanInstance->getInvocation().getModuleScanningHash());
   // Execute the scanning action, retrieving the in-memory result
-  auto DependenciesOrErr = performModuleScan(*QueryContext.ScanInstance.get(), 
-                                             QueryContext.ScanDiagnostics.get(),
-                                             cache);
+  auto DependenciesOrErr =
+      performModuleScan(*ScanningService, cache, *QueryContext);
+
   if (DependenciesOrErr.getError())
-    return generateHollowDiagnosticOutput(*ScanDiagnosticConsumer);
+    return generateHollowDiagnosticOutput(
+        QueryContext->InMemoryDiagnosticCollector->getDiagnosticsRef());
 
   return std::move(*DependenciesOrErr);
 }
@@ -301,50 +303,37 @@ DependencyScanningTool::getDependencies(
 llvm::ErrorOr<swiftscan_import_set_t>
 DependencyScanningTool::getImports(ArrayRef<const char *> Command,
                                    StringRef WorkingDirectory) {
-  // There may be errors as early as in instance initialization, so we must ensure
-  // we can catch those
-  auto ScanDiagnosticConsumer = std::make_shared<DependencyScanDiagnosticCollector>();
-  // The primary instance used to scan the query Swift source-code
-  auto QueryContextOrErr = initCompilerInstanceForScan(Command,
-                                                       WorkingDirectory,
-                                                       ScanDiagnosticConsumer);
-  if (QueryContextOrErr.getError())
-    return generateHollowDiagnosticOutputImportSet(*ScanDiagnosticConsumer);
+  // Diagnostics which may get collected during scanning instance
+  // initialization
+  std::vector<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+      InitializationDiagnostics;
 
-  auto QueryContext = std::move(*QueryContextOrErr);
+  // The primary instance used to scan the query Swift source-code
+  auto QueryContext = createScanQueryContext(Command, WorkingDirectory,
+                                             InitializationDiagnostics);
+  if (QueryContext.getError())
+    return generateHollowDiagnosticOutputImportSet(InitializationDiagnostics);
+  auto ScanInstance = QueryContext->ScanInstance.get();
 
   // Local scan cache instance, wrapping the shared global cache.
   ModuleDependenciesCache cache(
-      *ScanningService, QueryContext.ScanInstance->getMainModule()->getNameStr().str(),
-      QueryContext.ScanInstance->getInvocation().getFrontendOptions().ExplicitModulesOutputPath,
-      QueryContext.ScanInstance->getInvocation().getFrontendOptions().ExplicitSDKModulesOutputPath,
-      QueryContext.ScanInstance->getInvocation().getModuleScanningHash());
-  auto DependenciesOrErr = performModulePrescan(*QueryContext.ScanInstance.get(), 
-                                                QueryContext.ScanDiagnostics.get(),
-                                                cache);
+      ScanInstance->getMainModule()->getNameStr().str(),
+      ScanInstance->getInvocation().getModuleScanningHash());
+  // Execute the pre-scanning action, retrieving the in-memory result
+  auto DependenciesOrErr =
+      performModulePrescan(*ScanningService, cache, *QueryContext);
+
   if (DependenciesOrErr.getError())
-    return generateHollowDiagnosticOutputImportSet(*ScanDiagnosticConsumer);
+    return generateHollowDiagnosticOutputImportSet(
+        QueryContext->InMemoryDiagnosticCollector->getDiagnosticsRef());
 
   return std::move(*DependenciesOrErr);
 }
 
-std::vector<
-    DependencyScanDiagnosticCollector::ScannerDiagnosticInfo>
-DependencyScanningTool::getDiagnostics() {
-  llvm::sys::SmartScopedLock<true> Lock(DependencyScanningToolStateLock);
-  return CDC.Diagnostics;
-}
-
-void DependencyScanningTool::resetDiagnostics() {
-  llvm::sys::SmartScopedLock<true> Lock(DependencyScanningToolStateLock);
-  CDC.reset();
-}
-
-llvm::ErrorOr<ScanQueryInstance>
-DependencyScanningTool::initCompilerInstanceForScan(
-    ArrayRef<const char *> CommandArgs,
-    StringRef WorkingDir,
-    std::shared_ptr<DependencyScanDiagnosticCollector> scannerDiagnosticsCollector) {
+llvm::ErrorOr<ScanQueryContext> DependencyScanningTool::createScanQueryContext(
+    ArrayRef<const char *> CommandArgs, StringRef WorkingDir,
+    std::vector<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+        &InitializationDiagnostics) {
   // The remainder of this method operates on shared state in the
   // scanning service
   llvm::sys::SmartScopedLock<true> Lock(DependencyScanningToolStateLock);
@@ -353,61 +342,82 @@ DependencyScanningTool::initCompilerInstanceForScan(
   // client-side API plumbing.
   llvm::sys::SmartScopedLock<true> TargetInfoLock(TargetInfoMutex);
 
+  // There may be errors as early as in instance initialization, so we must
+  // ensure we can catch those
+  auto ScannerDiagnosticsCollector =
+      std::make_unique<DepScanInMemoryDiagnosticCollector>();
+
   // State unique to an individual scan
   auto Instance = std::make_unique<CompilerInstance>();
+  Instance->addDiagnosticConsumer(ScannerDiagnosticsCollector.get());
 
-  // FIXME: The shared CDC must be deprecated once all clients have switched
-  // to using per-scan diagnostic output embedded in the `swiftscan_dependency_graph_s`
-  Instance->addDiagnosticConsumer(&CDC);
-  Instance->addDiagnosticConsumer(scannerDiagnosticsCollector.get());
+  {
+    // In case we exit with an error, ensure the client gets the
+    // diagnostics collected so-far.
+    SWIFT_DEFER {
+      InitializationDiagnostics = ScannerDiagnosticsCollector->getDiagnostics();
+    };
+
+    // Basic error checking on the arguments
+    if (CommandArgs.empty()) {
+      Instance->getDiags().diagnose(SourceLoc(), diag::error_no_frontend_args);
+      return std::make_error_code(std::errc::invalid_argument);
+    }
 
-  // Basic error checking on the arguments
-  if (CommandArgs.empty()) {
-    Instance->getDiags().diagnose(SourceLoc(), diag::error_no_frontend_args);
-    return std::make_error_code(std::errc::invalid_argument);
-  }
+    CompilerInvocation Invocation;
+    SmallString<128> WorkingDirectory(WorkingDir);
+    if (WorkingDirectory.empty())
+      llvm::sys::fs::current_path(WorkingDirectory);
 
-  CompilerInvocation Invocation;
-  SmallString<128> WorkingDirectory(WorkingDir);
-  if (WorkingDirectory.empty())
-    llvm::sys::fs::current_path(WorkingDirectory);
+    // Parse/tokenize arguments.
+    std::string CommandString;
+    for (const auto *c : CommandArgs) {
+      CommandString.append(c);
+      CommandString.append(" ");
+    }
+    SmallVector<const char *, 4> Args;
+    llvm::BumpPtrAllocator Alloc;
+    llvm::StringSaver Saver(Alloc);
+    // Ensure that we use the Windows command line parsing on Windows as we need
+    // to ensure that we properly handle paths.
+    if (llvm::Triple(llvm::sys::getProcessTriple()).isOSWindows())
+      llvm::cl::TokenizeWindowsCommandLine(CommandString, Saver, Args);
+    else
+      llvm::cl::TokenizeGNUCommandLine(CommandString, Saver, Args);
+
+    if (Invocation.parseArgs(Args, Instance->getDiags(),
+                             nullptr, WorkingDirectory, "/tmp/foo")) {
+      return std::make_error_code(std::errc::invalid_argument);
+    }
 
-  // Parse/tokenize arguments.
-  std::string CommandString;
-  for (const auto *c : CommandArgs) {
-    CommandString.append(c);
-    CommandString.append(" ");
-  }
-  SmallVector<const char *, 4> Args;
-  llvm::BumpPtrAllocator Alloc;
-  llvm::StringSaver Saver(Alloc);
-  // Ensure that we use the Windows command line parsing on Windows as we need
-  // to ensure that we properly handle paths.
-  if (llvm::Triple(llvm::sys::getProcessTriple()).isOSWindows())
-    llvm::cl::TokenizeWindowsCommandLine(CommandString, Saver, Args);
-  else
-    llvm::cl::TokenizeGNUCommandLine(CommandString, Saver, Args);
+    // Setup the instance
+    std::string InstanceSetupError;
+    if (Instance->setup(Invocation, InstanceSetupError))
+      return std::make_error_code(std::errc::not_supported);
 
-  if (Invocation.parseArgs(Args, Instance->getDiags(),
-                           nullptr, WorkingDirectory, "/tmp/foo")) {
-    return std::make_error_code(std::errc::invalid_argument);
-  }
+    Invocation.getFrontendOptions().LLVMArgs.clear();
 
-  // Setup the instance
-  std::string InstanceSetupError;
-  if (Instance->setup(Invocation, InstanceSetupError)) {
-    return std::make_error_code(std::errc::not_supported);
-  }
-  Invocation.getFrontendOptions().LLVMArgs.clear();
+    // Setup the caching service after the instance finishes setup.
+    if (ScanningService->setupCachingDependencyScanningService(*Instance))
+      return std::make_error_code(std::errc::invalid_argument);
 
-  // Setup the caching service after the instance finishes setup.
-  if (ScanningService->setupCachingDependencyScanningService(*Instance))
-    return std::make_error_code(std::errc::invalid_argument);
+    (void)Instance->getMainModule();
+  }
 
-  (void)Instance->getMainModule();
+  auto SerializedDiagnosticsOutputPath =
+      Instance->getInvocation()
+          .getSerializedDiagnosticsPathForAtMostOnePrimary();
+  std::unique_ptr<DiagnosticConsumer> SerailizedDiagnosticsConsumer;
+  if (!SerializedDiagnosticsOutputPath.empty()) {
+    SerailizedDiagnosticsConsumer =
+        swift::serialized_diagnostics::createThreadSafeConsumer(
+            SerializedDiagnosticsOutputPath, false);
+    Instance->addDiagnosticConsumer(SerailizedDiagnosticsConsumer.get());
+  }
 
-  return ScanQueryInstance{std::move(Instance), 
-                           scannerDiagnosticsCollector};
+  return ScanQueryContext{std::move(Instance),
+                          std::move(ScannerDiagnosticsCollector),
+                          std::move(SerailizedDiagnosticsConsumer)};
 }
 
 } // namespace dependencies
diff --git a/lib/DependencyScan/ModuleDependencyCacheSerialization.cpp b/lib/DependencyScan/ModuleDependencyCacheSerialization.cpp
index 7dd4d09569e07..c3ed6f2fb8248 100644
--- a/lib/DependencyScan/ModuleDependencyCacheSerialization.cpp
+++ b/lib/DependencyScan/ModuleDependencyCacheSerialization.cpp
@@ -45,10 +45,12 @@ class ModuleDependenciesCacheDeserializer {
   std::vector<LinkLibrary> LinkLibraries;
   std::vector<std::vector<uint64_t>> ArraysOfLinkLibraryIDs;
   std::vector<std::pair<std::string, MacroPluginDependency>> MacroDependencies;
+  std::vector<serialization::SearchPath> SearchPaths;
   std::vector<std::vector<uint64_t>> ArraysOfMacroDependenciesIDs;
   std::vector<ScannerImportStatementInfo> ImportStatements;
   std::vector<std::vector<uint64_t>> ArraysOfImportStatementIDs;
   std::vector<std::vector<uint64_t>> ArraysOfOptionalImportStatementIDs;
+  std::vector<std::vector<uint64_t>> ArraysOfSearchPathIDs;
 
   llvm::BitstreamCursor Cursor;
   SmallVector<uint64_t, 64> Scratch;
@@ -66,6 +68,8 @@ class ModuleDependenciesCacheDeserializer {
   std::optional<std::vector<LinkLibrary>> getLinkLibraryArray(unsigned n);
   std::optional<std::vector<std::pair<std::string, MacroPluginDependency>>>
   getMacroDependenciesArray(unsigned n);
+  std::optional<std::vector<serialization::SearchPath>>
+  getSearchPathArray(unsigned n);
   std::optional<std::vector<ScannerImportStatementInfo>>
   getImportStatementInfoArray(unsigned n);
   std::optional<std::vector<ScannerImportStatementInfo>>
@@ -218,9 +222,6 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
 
   bool hasCurrentModule = false;
   std::string currentModuleName;
-  std::vector<ScannerImportStatementInfo> currentModuleImports;
-  std::vector<ScannerImportStatementInfo> currentOptionalModuleImports;
-
   std::vector<ModuleDependencyID> importedSwiftDependenciesIDs;
   std::vector<ModuleDependencyID> importedClangDependenciesIDs;
   std::vector<ModuleDependencyID> crossImportOverlayDependenciesIDs;
@@ -232,27 +233,12 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
   std::vector<ScannerImportStatementInfo> importStatements;
   std::vector<ScannerImportStatementInfo> optionalImportStatements;
 
-  std::vector<std::string> auxiliaryFiles;
-
   auto addCommonDependencyInfo =
-      [&currentModuleImports, &currentOptionalModuleImports,
-       &importedClangDependenciesIDs, &auxiliaryFiles,
-       &macroDependencies](ModuleDependencyInfo &moduleDep) {
-        // Add imports of this module
-        for (const auto &moduleName : currentModuleImports)
-          moduleDep.addModuleImport(moduleName.importIdentifier,
-                                    moduleName.isExported);
-        // Add optional imports of this module
-        for (const auto &moduleName : currentOptionalModuleImports)
-          moduleDep.addOptionalModuleImport(moduleName.importIdentifier,
-                                            moduleName.isExported);
-
+      [&importedClangDependenciesIDs, &macroDependencies]
+      (ModuleDependencyInfo &moduleDep) {
         // Add qualified dependencies of this module
         moduleDep.setImportedClangDependencies(importedClangDependenciesIDs);
 
-        // Add any auxiliary files
-        moduleDep.setAuxiliaryFiles(auxiliaryFiles);
-
         // Add macro dependencies
         for (const auto &md : macroDependencies)
           moduleDep.addMacroDependency(md.first, md.second.LibraryPath,
@@ -297,7 +283,7 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
           llvm::report_fatal_error("Bad bridging module dependencies");
         llvm::StringSet<> alreadyAdded;
         std::vector<ModuleDependencyID> bridgingModuleDepIDs;
-        for (const auto &mod : bridgingModuleDeps.value())
+        for (const auto &mod : *bridgingModuleDeps)
           bridgingModuleDepIDs.push_back(
               ModuleDependencyID{mod, ModuleDependencyKind::Clang});
         moduleDep.setHeaderClangDependencies(bridgingModuleDepIDs);
@@ -364,7 +350,7 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
         llvm::report_fatal_error("Bad link library identifier");
 
       LinkLibraries.emplace_back(
-          libraryIdentifier.value(),
+          *libraryIdentifier,
                       isFramework ? LibraryKind::Framework
                                   : LibraryKind::Library,
                       isStatic, shouldForceLoad);
@@ -395,8 +381,8 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
         llvm::report_fatal_error("Bad macro dependency: no executable path");
 
       MacroDependencies.push_back(
-          {macroModuleName.value(),
-           MacroPluginDependency{libraryPath.value(), executablePath.value()}});
+          {*macroModuleName,
+           MacroPluginDependency{*libraryPath, *executablePath}});
       break;
     }
 
@@ -407,13 +393,33 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
       break;
     }
 
+    case SEARCH_PATH_NODE: {
+      unsigned pathStrID;
+      bool isFramework, isSystem;
+      SearchPathLayout::readRecord(Scratch, pathStrID, isFramework, isSystem);
+      auto pathStr = getIdentifier(pathStrID);
+      if (!pathStr)
+        llvm::report_fatal_error("Bad search path: no path string");
+      SearchPaths.push_back({*pathStr, isFramework, isSystem});
+      break;
+    }
+
+    case SEARCH_PATH_ARRAY_NODE: {
+      ArrayRef<uint64_t> identifierIDs;
+      SearchPathArrayLayout::readRecord(Scratch, identifierIDs);
+      ArraysOfSearchPathIDs.push_back(identifierIDs.vec());
+      break;
+    }
+
     case IMPORT_STATEMENT_NODE: {
       unsigned importIdentifierID, bufferIdentifierID;
       unsigned lineNumber, columnNumber;
       bool isOptional, isExported;
+      uint8_t rawAccessLevel;
       ImportStatementLayout::readRecord(Scratch, importIdentifierID,
                                         bufferIdentifierID, lineNumber,
-                                        columnNumber, isOptional, isExported);
+                                        columnNumber, isOptional, isExported,
+                                        rawAccessLevel);
       auto importIdentifier = getIdentifier(importIdentifierID);
       if (!importIdentifier)
         llvm::report_fatal_error("Bad import statement info: no import name");
@@ -422,10 +428,14 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
       if (!bufferIdentifier)
         llvm::report_fatal_error(
             "Bad import statement info: no buffer identifier");
-      ImportStatements.push_back(ScannerImportStatementInfo(
-          importIdentifier.value(), isExported,
-          ScannerImportStatementInfo::ImportDiagnosticLocationInfo(
-              bufferIdentifier.value(), lineNumber, columnNumber)));
+      if (bufferIdentifier->empty())
+        ImportStatements.push_back(ScannerImportStatementInfo(
+            *importIdentifier, isExported, AccessLevel(rawAccessLevel)));
+      else
+        ImportStatements.push_back(ScannerImportStatementInfo(
+            *importIdentifier, isExported, AccessLevel(rawAccessLevel),
+            ScannerImportStatementInfo::ImportDiagnosticLocationInfo(
+                *bufferIdentifier, lineNumber, columnNumber)));
       break;
     }
 
@@ -450,8 +460,7 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
           importedSwiftDependenciesIDsArrayID,
           importedClangDependenciesIDsArrayID,
           crossImportOverlayDependenciesIDsArrayID,
-          swiftOverlayDependenciesIDsArrayID, moduleCacheKeyID,
-          AuxiliaryFilesArrayID;
+          swiftOverlayDependenciesIDsArrayID, moduleCacheKeyID;
 
       ModuleInfoLayout::readRecord(Scratch, moduleNameID, moduleImportsArrayID,
                                    optionalImportsArrayID, linkLibraryArrayID,
@@ -460,7 +469,7 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
                                    importedClangDependenciesIDsArrayID,
                                    crossImportOverlayDependenciesIDsArrayID,
                                    swiftOverlayDependenciesIDsArrayID,
-                                   moduleCacheKeyID, AuxiliaryFilesArrayID);
+                                   moduleCacheKeyID);
       auto moduleName = getIdentifier(moduleNameID);
       if (!moduleName)
         llvm::report_fatal_error("Bad module name");
@@ -470,19 +479,12 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
           getImportStatementInfoArray(moduleImportsArrayID);
       if (!optionalImportStatementInfos)
         llvm::report_fatal_error("Bad direct Swift dependencies: no imports");
-      importStatements = optionalImportStatementInfos.value();
+      importStatements = *optionalImportStatementInfos;
 
       auto optionalOptionalImportStatementInfos =
           getOptionalImportStatementInfoArray(optionalImportsArrayID);
-      if (!optionalOptionalImportStatementInfos)
-        llvm::report_fatal_error(
-            "Bad direct Swift dependencies: no optional imports");
-      optionalImportStatements = optionalOptionalImportStatementInfos.value();
-
-      auto optionalAuxiliaryFiles = getStringArray(AuxiliaryFilesArrayID);
-      if (optionalAuxiliaryFiles.has_value())
-        for (const auto &af : optionalAuxiliaryFiles.value())
-          auxiliaryFiles.push_back(af);
+      if (optionalOptionalImportStatementInfos)
+        optionalImportStatements = *optionalOptionalImportStatementInfos;
 
       auto optionalImportedSwiftDependenciesIDs =
           getModuleDependencyIDArray(importedSwiftDependenciesIDsArrayID);
@@ -490,7 +492,7 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
         llvm::report_fatal_error(
             "Bad direct Swift dependencies: no qualified dependencies");
       importedSwiftDependenciesIDs =
-          optionalImportedSwiftDependenciesIDs.value();
+          *optionalImportedSwiftDependenciesIDs;
 
       auto optionalImportedClangDependenciesIDs =
           getModuleDependencyIDArray(importedClangDependenciesIDsArrayID);
@@ -498,7 +500,7 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
         llvm::report_fatal_error(
             "Bad direct Clang dependencies: no qualified dependencies");
       importedClangDependenciesIDs =
-          optionalImportedClangDependenciesIDs.value();
+          *optionalImportedClangDependenciesIDs;
 
       auto optionalCrossImportOverlayDependenciesIDs =
           getModuleDependencyIDArray(crossImportOverlayDependenciesIDsArrayID);
@@ -506,14 +508,14 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
         llvm::report_fatal_error(
             "Bad Cross-Import Overlay dependencies: no qualified dependencies");
       crossImportOverlayDependenciesIDs =
-          optionalCrossImportOverlayDependenciesIDs.value();
+          *optionalCrossImportOverlayDependenciesIDs;
 
       auto optionalSwiftOverlayDependenciesIDs =
           getModuleDependencyIDArray(swiftOverlayDependenciesIDsArrayID);
       if (!optionalSwiftOverlayDependenciesIDs)
         llvm::report_fatal_error(
             "Bad Swift Overlay dependencies: no qualified dependencies");
-      swiftOverlayDependenciesIDs = optionalSwiftOverlayDependenciesIDs.value();
+      swiftOverlayDependenciesIDs = *optionalSwiftOverlayDependenciesIDs;
 
       auto optionalLinkLibraries = getLinkLibraryArray(linkLibraryArrayID);
       if (!optionalLinkLibraries)
@@ -587,7 +589,7 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
 
       // Form the dependencies storage object
       auto moduleDep = ModuleDependencyInfo::forSwiftInterfaceModule(
-          optionalSwiftInterfaceFile.value(), compiledCandidatesRefs,
+          *optionalSwiftInterfaceFile, compiledCandidatesRefs,
           buildCommandRefs, importStatements, optionalImportStatements,
           linkLibraries, isFramework, isStatic, *rootFileSystemID,
           *moduleCacheKey, *userModuleVersion);
@@ -675,14 +677,16 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
         llvm::report_fatal_error(
             "Unexpected SWIFT_BINARY_MODULE_DETAILS_NODE record");
       unsigned compiledModulePathID, moduleDocPathID, moduleSourceInfoPathID,
-          headerImportID, definingInterfacePathID,
+          headerImportID, definingInterfacePathID, searchPathArrayID,
           headerModuleDependenciesArrayID, headerImportsSourceFilesArrayID,
-          isFramework, isStatic, moduleCacheKeyID, userModuleVersionID;
+          isFramework, isStatic, isBuiltWithCxxInterop, moduleCacheKeyID,
+          userModuleVersionID;
       SwiftBinaryModuleDetailsLayout::readRecord(
           Scratch, compiledModulePathID, moduleDocPathID,
           moduleSourceInfoPathID, headerImportID, definingInterfacePathID,
           headerModuleDependenciesArrayID, headerImportsSourceFilesArrayID,
-          isFramework, isStatic, moduleCacheKeyID, userModuleVersionID);
+          searchPathArrayID, isFramework, isStatic, isBuiltWithCxxInterop,
+          moduleCacheKeyID, userModuleVersionID);
 
       auto compiledModulePath = getIdentifier(compiledModulePathID);
       if (!compiledModulePath)
@@ -707,13 +711,17 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
       if (!definingInterfacePath)
         llvm::report_fatal_error(
             "Bad binary direct dependencies: no defining interface path");
+      auto searchPaths = getSearchPathArray(searchPathArrayID);
+      if (!searchPaths)
+        llvm::report_fatal_error(
+            "Bad binary direct dependencies: no serialized search paths");
 
       // Form the dependencies storage object
       auto moduleDep = ModuleDependencyInfo::forSwiftBinaryModule(
           *compiledModulePath, *moduleDocPath, *moduleSourceInfoPath,
-          currentModuleImports, currentOptionalModuleImports, linkLibraries,
-          *headerImport, *definingInterfacePath, isFramework, isStatic,
-          *moduleCacheKey, *userModuleVersion);
+          importStatements, optionalImportStatements, linkLibraries,
+          *searchPaths, *headerImport, *definingInterfacePath, isFramework,
+          isStatic, isBuiltWithCxxInterop, *moduleCacheKey, *userModuleVersion);
 
       addCommonDependencyInfo(moduleDep);
       addSwiftCommonDependencyInfo(moduleDep);
@@ -744,34 +752,6 @@ bool ModuleDependenciesCacheDeserializer::readGraph(
       break;
     }
 
-    case SWIFT_PLACEHOLDER_MODULE_DETAILS_NODE: {
-      if (!hasCurrentModule)
-        llvm::report_fatal_error(
-            "Unexpected SWIFT_PLACEHOLDER_MODULE_DETAILS_NODE record");
-      unsigned compiledModulePathID, moduleDocPathID, moduleSourceInfoPathID;
-      SwiftPlaceholderModuleDetailsLayout::readRecord(
-          Scratch, compiledModulePathID, moduleDocPathID,
-          moduleSourceInfoPathID);
-
-      auto compiledModulePath = getIdentifier(compiledModulePathID);
-      if (!compiledModulePath)
-        llvm::report_fatal_error("Bad compiled module path");
-      auto moduleDocPath = getIdentifier(moduleDocPathID);
-      if (!moduleDocPath)
-        llvm::report_fatal_error("Bad module doc path");
-      auto moduleSourceInfoPath = getIdentifier(moduleSourceInfoPathID);
-      if (!moduleSourceInfoPath)
-        llvm::report_fatal_error("Bad module source info path");
-
-      // Form the dependencies storage object
-      auto moduleDep = ModuleDependencyInfo::forPlaceholderSwiftModuleStub(
-          *compiledModulePath, *moduleDocPath, *moduleSourceInfoPath);
-
-      cache.recordDependency(currentModuleName, std::move(moduleDep));
-      hasCurrentModule = false;
-      break;
-    }
-
     case CLANG_MODULE_DETAILS_NODE: {
       if (!hasCurrentModule)
         llvm::report_fatal_error("Unexpected CLANG_MODULE_DETAILS_NODE record");
@@ -930,6 +910,25 @@ ModuleDependenciesCacheDeserializer::getMacroDependenciesArray(unsigned n) {
   return result;
 }
 
+std::optional<std::vector<serialization::SearchPath>>
+ModuleDependenciesCacheDeserializer::getSearchPathArray(unsigned n) {
+  if (n == 0)
+    return std::vector<serialization::SearchPath>();
+
+  --n;
+  if (n >= ArraysOfSearchPathIDs.size())
+    return std::nullopt;
+
+  auto &llIDs = ArraysOfSearchPathIDs[n];
+
+  auto IDtoLLMap = [this](unsigned index) { return SearchPaths[index]; };
+  std::vector<serialization::SearchPath> result;
+  result.reserve(llIDs.size());
+  std::transform(llIDs.begin(), llIDs.end(), std::back_inserter(result),
+                 IDtoLLMap);
+  return result;
+}
+
 std::optional<std::vector<ScannerImportStatementInfo>>
 ModuleDependenciesCacheDeserializer::getImportStatementInfoArray(unsigned n) {
   if (n == 0)
@@ -984,10 +983,9 @@ ModuleDependenciesCacheDeserializer::getOptionalImportStatementInfoArray(
 std::optional<std::vector<ModuleDependencyID>>
 ModuleDependenciesCacheDeserializer::getModuleDependencyIDArray(unsigned n) {
   auto encodedIdentifierStringArray = getStringArray(n);
-  if (encodedIdentifierStringArray.has_value()) {
+  if (encodedIdentifierStringArray) {
     static const std::string textualPrefix("swiftTextual");
     static const std::string binaryPrefix("swiftBinary");
-    static const std::string placeholderPrefix("swiftPlaceholder");
     static const std::string clangPrefix("clang");
     std::vector<ModuleDependencyID> result;
     for (const auto &encodedIdentifierString : *encodedIdentifierStringArray) {
@@ -1002,11 +1000,6 @@ ModuleDependenciesCacheDeserializer::getModuleDependencyIDArray(unsigned n) {
         auto moduleName =
             encodedIdentifierString.substr(binaryPrefix.size() + 1);
         id = {moduleName, ModuleDependencyKind::SwiftBinary};
-      } else if (!encodedIdentifierString.compare(0, placeholderPrefix.size(),
-                                                  placeholderPrefix)) {
-        auto moduleName =
-            encodedIdentifierString.substr(placeholderPrefix.size() + 1);
-        id = {moduleName, ModuleDependencyKind::SwiftPlaceholder};
       } else {
         auto moduleName =
             encodedIdentifierString.substr(clangPrefix.size() + 1);
@@ -1053,7 +1046,6 @@ enum ModuleIdentifierArrayKind : uint8_t {
   ImportedClangDependenciesIDs,
   CrossImportOverlayDependenciesIDs,
   SwiftOverlayDependenciesIDs,
-  AuxiliaryFileIDs,
   CompiledModuleCandidates,
   BuildCommandLine,
   SourceFiles,
@@ -1106,6 +1098,7 @@ class ModuleDependenciesCacheSerializer {
 
   std::unordered_map<ModuleDependencyID, unsigned> LinkLibraryArrayIDsMap;
   std::unordered_map<ModuleDependencyID, unsigned> MacroDependenciesArrayIDsMap;
+  std::unordered_map<ModuleDependencyID, unsigned> SearchPathArrayIDsMap;
   std::unordered_map<ModuleDependencyID, unsigned> ImportInfosArrayIDsMap;
   std::unordered_map<ModuleDependencyID, unsigned>
       OptionalImportInfosArrayIDsMap;
@@ -1132,6 +1125,7 @@ class ModuleDependenciesCacheSerializer {
                                 ModuleIdentifierArrayKind arrayKind) const;
   unsigned getLinkLibrariesArrayID(ModuleDependencyID moduleID) const;
   unsigned getMacroDependenciesArrayID(ModuleDependencyID moduleID) const;
+  unsigned getSearchPathArrayID(ModuleDependencyID moduleID) const;
   unsigned getImportStatementsArrayID(ModuleDependencyID moduleID) const;
   unsigned
   getOptionalImportStatementsArrayID(ModuleDependencyID moduleID) const;
@@ -1168,10 +1162,15 @@ class ModuleDependenciesCacheSerializer {
   unsigned writeMacroDependencies(const ModuleDependencyInfo &dependencyInfo);
   void writeMacroDependenciesArray(unsigned startIndex, unsigned count);
 
+  void writeSearchPaths(const ModuleDependenciesCache &cache);
+  unsigned writeSearchPaths(const SwiftBinaryModuleDependencyStorage &dependencyInfo);
+  void writeSearchPathsArray(unsigned startIndex, unsigned count);
+
   void writeImportStatementInfos(const ModuleDependenciesCache &cache);
   unsigned writeImportStatementInfos(const ModuleDependencyInfo &dependencyInfo,
                                      bool optional);
   void writeImportStatementInfosArray(unsigned startIndex, unsigned count);
+  void writeOptionalImportStatementInfosArray(unsigned startIndex, unsigned count);
 
   void writeModuleInfo(ModuleDependencyID moduleID,
                        const ModuleDependencyInfo &dependencyInfo);
@@ -1228,6 +1227,8 @@ void ModuleDependenciesCacheSerializer::writeBlockInfoBlock() {
   BLOCK_RECORD(graph_block, LINK_LIBRARY_ARRAY_NODE);
   BLOCK_RECORD(graph_block, MACRO_DEPENDENCY_NODE);
   BLOCK_RECORD(graph_block, MACRO_DEPENDENCY_ARRAY_NODE);
+  BLOCK_RECORD(graph_block, SEARCH_PATH_NODE);
+  BLOCK_RECORD(graph_block, SEARCH_PATH_ARRAY_NODE);
   BLOCK_RECORD(graph_block, IMPORT_STATEMENT_NODE);
   BLOCK_RECORD(graph_block, IMPORT_STATEMENT_ARRAY_NODE);
   BLOCK_RECORD(graph_block, OPTIONAL_IMPORT_STATEMENT_ARRAY_NODE);
@@ -1235,7 +1236,6 @@ void ModuleDependenciesCacheSerializer::writeBlockInfoBlock() {
   BLOCK_RECORD(graph_block, SWIFT_INTERFACE_MODULE_DETAILS_NODE);
   BLOCK_RECORD(graph_block, SWIFT_SOURCE_MODULE_DETAILS_NODE);
   BLOCK_RECORD(graph_block, SWIFT_BINARY_MODULE_DETAILS_NODE);
-  BLOCK_RECORD(graph_block, SWIFT_PLACEHOLDER_MODULE_DETAILS_NODE);
   BLOCK_RECORD(graph_block, CLANG_MODULE_DETAILS_NODE);
 }
 
@@ -1288,8 +1288,8 @@ void ModuleDependenciesCacheSerializer::writeLinkLibraries(
     for (const auto &entry : modMap) {
       ModuleDependencyID moduleID = {entry.getKey().str(), kind};
       auto optionalDependencyInfo = cache.findDependency(moduleID);
-      assert(optionalDependencyInfo.has_value() && "Expected dependency info.");
-      auto dependencyInfo = optionalDependencyInfo.value();
+      assert(optionalDependencyInfo && "Expected dependency info.");
+      auto dependencyInfo = *optionalDependencyInfo;
       unsigned numLLs = writeLinkLibraryInfos(*dependencyInfo);
       moduleLLArrayMap.insert({moduleID, std::make_pair(lastLLIndex, numLLs)});
       lastLLIndex += numLLs;
@@ -1343,8 +1343,8 @@ void ModuleDependenciesCacheSerializer::writeMacroDependencies(
     for (const auto &entry : modMap) {
       ModuleDependencyID moduleID = {entry.getKey().str(), kind};
       auto optionalDependencyInfo = cache.findDependency(moduleID);
-      assert(optionalDependencyInfo.has_value() && "Expected dependency info.");
-      auto dependencyInfo = optionalDependencyInfo.value();
+      assert(optionalDependencyInfo && "Expected dependency info.");
+      auto dependencyInfo = *optionalDependencyInfo;
       unsigned numMDs = writeMacroDependencies(*dependencyInfo);
       moduleMacroDepArrayMap.insert(
           {moduleID, std::make_pair(lastMDIndex, numMDs)});
@@ -1389,6 +1389,52 @@ void ModuleDependenciesCacheSerializer::writeMacroDependenciesArray(
       Out, ScratchRecord, AbbrCodes[MacroDependencyArrayLayout::Code], vec);
 }
 
+void ModuleDependenciesCacheSerializer::writeSearchPaths(const ModuleDependenciesCache &cache) {
+  unsigned lastSPIndex = 0;
+  std::map<ModuleDependencyID, std::pair<unsigned, unsigned>>
+      moduleSearchPathArrayMap;
+
+  auto modMap = cache.getDependenciesMap(ModuleDependencyKind::SwiftBinary);
+  for (const auto &entry : modMap) {
+    ModuleDependencyID moduleID = {entry.getKey().str(), ModuleDependencyKind::SwiftBinary};
+    auto optionalDependencyInfo = cache.findDependency(moduleID);
+    assert(optionalDependencyInfo && "Expected dependency info.");
+    auto dependencyInfo = *optionalDependencyInfo;
+    unsigned numSPs = writeSearchPaths(*dependencyInfo->getAsSwiftBinaryModule());
+    moduleSearchPathArrayMap.insert({moduleID, std::make_pair(lastSPIndex, numSPs)});
+    lastSPIndex += numSPs;
+  }
+
+  unsigned lastSPArrayIndex = 1;
+  for (const auto &entry : modMap) {
+    ModuleDependencyID moduleID = {entry.getKey().str(), ModuleDependencyKind::SwiftBinary};
+    auto entries = moduleSearchPathArrayMap.at(moduleID);
+    if (entries.second == 0)
+      continue;
+    writeSearchPathsArray(entries.first, entries.second);
+    SearchPathArrayIDsMap.insert({moduleID, lastSPArrayIndex++});
+  }
+}
+unsigned ModuleDependenciesCacheSerializer::writeSearchPaths(const SwiftBinaryModuleDependencyStorage &dependencyInfo) {
+  using namespace graph_block;
+  for (const auto &searchPath : dependencyInfo.serializedSearchPaths) {
+    SearchPathLayout::emitRecord(
+        Out, ScratchRecord, AbbrCodes[SearchPathLayout::Code],
+        getIdentifier(searchPath.Path),
+        searchPath.IsFramework,
+        searchPath.IsSystem);
+  }
+  return dependencyInfo.serializedSearchPaths.size();
+}
+
+void ModuleDependenciesCacheSerializer::writeSearchPathsArray(unsigned startIndex, unsigned count) {
+  using namespace graph_block;
+  std::vector<unsigned> vec(count);
+  std::iota(vec.begin(), vec.end(), startIndex);
+  SearchPathArrayLayout::emitRecord(
+      Out, ScratchRecord, AbbrCodes[SearchPathArrayLayout::Code], vec);
+}
+
 void ModuleDependenciesCacheSerializer::writeImportStatementInfos(
     const ModuleDependenciesCache &cache) {
   unsigned lastImportInfoIndex = 0;
@@ -1399,11 +1445,11 @@ void ModuleDependenciesCacheSerializer::writeImportStatementInfos(
   for (auto kind = ModuleDependencyKind::FirstKind;
        kind != ModuleDependencyKind::LastKind; ++kind) {
     auto modMap = cache.getDependenciesMap(kind);
-    for (const auto &entry : modMap) {
-      ModuleDependencyID moduleID = {entry.getKey().str(), kind};
+    for (const auto &entry : modMap.keys()) {
+      ModuleDependencyID moduleID = {entry.str(), kind};
       auto optionalDependencyInfo = cache.findDependency(moduleID);
-      assert(optionalDependencyInfo.has_value() && "Expected dependency info.");
-      auto dependencyInfo = optionalDependencyInfo.value();
+      assert(optionalDependencyInfo && "Expected dependency info.");
+      auto dependencyInfo = *optionalDependencyInfo;
 
       auto numImportInfos =
           writeImportStatementInfos(*dependencyInfo, /* optional */ false);
@@ -1414,22 +1460,28 @@ void ModuleDependenciesCacheSerializer::writeImportStatementInfos(
       auto numOptionalImportInfos =
           writeImportStatementInfos(*dependencyInfo, /* optional */ true);
       optionalImportInfoArrayMap.insert(
-          {moduleID, std::make_pair(lastImportInfoIndex, numImportInfos)});
+          {moduleID, std::make_pair(lastImportInfoIndex, numOptionalImportInfos)});
       lastImportInfoIndex += numOptionalImportInfos;
     }
   }
 
   unsigned lastImportInfoArrayIndex = 1;
+  unsigned lastOptionalImportInfoArrayIndex = 1;
   for (auto kind = ModuleDependencyKind::FirstKind;
        kind != ModuleDependencyKind::LastKind; ++kind) {
     auto modMap = cache.getDependenciesMap(kind);
-    for (const auto &entry : modMap) {
-      ModuleDependencyID moduleID = {entry.getKey().str(), kind};
+    for (const auto &entry : modMap.keys()) {
+      ModuleDependencyID moduleID = {entry.str(), kind};
       auto entries = importInfoArrayMap.at(moduleID);
-      if (entries.second == 0)
-        continue;
-      writeImportStatementInfosArray(entries.first, entries.second);
-      ImportInfosArrayIDsMap.insert({moduleID, lastImportInfoArrayIndex++});
+      if (entries.second != 0) {
+        writeImportStatementInfosArray(entries.first, entries.second);
+        ImportInfosArrayIDsMap.insert({moduleID, lastImportInfoArrayIndex++});
+      }
+      auto optionalEntries = optionalImportInfoArrayMap.at(moduleID);
+      if (optionalEntries.second != 0) {
+        writeOptionalImportStatementInfosArray(optionalEntries.first, optionalEntries.second);
+        OptionalImportInfosArrayIDsMap.insert({moduleID, lastOptionalImportInfoArrayIndex++});
+      }
     }
   }
 }
@@ -1440,22 +1492,33 @@ unsigned ModuleDependenciesCacheSerializer::writeImportStatementInfos(
   size_t count = 0;
   auto emitImportStatementInfo = [this, &count](const auto &importInfo,
                                                 bool isOptional) {
-    for (auto &importLoc : importInfo.importLocations) {
+    if (importInfo.importLocations.empty()) {
       ImportStatementLayout::emitRecord(
           Out, ScratchRecord, AbbrCodes[ImportStatementLayout::Code],
           getIdentifier(importInfo.importIdentifier),
-          getIdentifier(importLoc.bufferIdentifier), importLoc.lineNumber,
-          importLoc.columnNumber, isOptional, importInfo.isExported);
+          0, 0, 0, isOptional, importInfo.isExported,
+          static_cast<std::underlying_type<AccessLevel>::type>(importInfo.accessLevel));
       count++;
+    } else {
+      for (auto &importLoc : importInfo.importLocations) {
+        ImportStatementLayout::emitRecord(
+            Out, ScratchRecord, AbbrCodes[ImportStatementLayout::Code],
+            getIdentifier(importInfo.importIdentifier),
+            getIdentifier(importLoc.bufferIdentifier), importLoc.lineNumber,
+            importLoc.columnNumber, isOptional, importInfo.isExported,
+            static_cast<std::underlying_type<AccessLevel>::type>(importInfo.accessLevel));
+        count++;
+      }
     }
   };
 
-  for (auto &importInfo : dependencyInfo.getModuleImports())
-    emitImportStatementInfo(importInfo, false);
-
-  for (auto &importInfo : dependencyInfo.getOptionalModuleImports())
-    emitImportStatementInfo(importInfo, true);
-
+  if (!optional) {
+    for (auto &importInfo : dependencyInfo.getModuleImports())
+      emitImportStatementInfo(importInfo, false);
+  } else {
+    for (auto &importInfo : dependencyInfo.getOptionalModuleImports())
+      emitImportStatementInfo(importInfo, true);
+  }
   return count;
 }
 
@@ -1468,6 +1531,15 @@ void ModuleDependenciesCacheSerializer::writeImportStatementInfosArray(
       Out, ScratchRecord, AbbrCodes[ImportStatementArrayLayout::Code], vec);
 }
 
+void ModuleDependenciesCacheSerializer::writeOptionalImportStatementInfosArray(
+    unsigned startIndex, unsigned count) {
+  using namespace graph_block;
+  std::vector<unsigned> vec(count);
+  std::iota(vec.begin(), vec.end(), startIndex);
+  OptionalImportStatementArrayLayout::emitRecord(
+      Out, ScratchRecord, AbbrCodes[OptionalImportStatementArrayLayout::Code], vec);
+}
+
 void ModuleDependenciesCacheSerializer::writeModuleInfo(
     ModuleDependencyID moduleID, const ModuleDependencyInfo &dependencyInfo) {
   using namespace graph_block;
@@ -1486,9 +1558,7 @@ void ModuleDependenciesCacheSerializer::writeModuleInfo(
           ModuleIdentifierArrayKind::CrossImportOverlayDependenciesIDs),
       getIdentifierArrayID(
           moduleID, ModuleIdentifierArrayKind::SwiftOverlayDependenciesIDs),
-      getIdentifier(dependencyInfo.getModuleCacheKey()),
-      getIdentifierArrayID(moduleID,
-                           ModuleIdentifierArrayKind::AuxiliaryFileIDs));
+      getIdentifier(dependencyInfo.getModuleCacheKey()));
 
   switch (dependencyInfo.getKind()) {
   case swift::ModuleDependencyKind::SwiftInterface: {
@@ -1500,8 +1570,8 @@ void ModuleDependenciesCacheSerializer::writeModuleInfo(
         getIdentifier(swiftTextDeps->swiftInterfaceFile);
     unsigned bridgingHeaderFileId =
         swiftTextDeps->textualModuleDetails.bridgingHeaderFile
-            ? getIdentifier(swiftTextDeps->textualModuleDetails
-                                .bridgingHeaderFile.value())
+            ? getIdentifier(*(swiftTextDeps->textualModuleDetails
+                                .bridgingHeaderFile))
             : 0;
     SwiftInterfaceModuleDetailsLayout::emitRecord(
         Out, ScratchRecord, AbbrCodes[SwiftInterfaceModuleDetailsLayout::Code],
@@ -1529,8 +1599,8 @@ void ModuleDependenciesCacheSerializer::writeModuleInfo(
     assert(swiftSourceDeps);
     unsigned bridgingHeaderFileId =
         swiftSourceDeps->textualModuleDetails.bridgingHeaderFile
-            ? getIdentifier(swiftSourceDeps->textualModuleDetails
-                                .bridgingHeaderFile.value())
+            ? getIdentifier(*(swiftSourceDeps->textualModuleDetails
+                                .bridgingHeaderFile))
             : 0;
     SwiftSourceModuleDetailsLayout::emitRecord(
         Out, ScratchRecord, AbbrCodes[SwiftSourceModuleDetailsLayout::Code],
@@ -1568,21 +1638,11 @@ void ModuleDependenciesCacheSerializer::writeModuleInfo(
         getIdentifierArrayID(
             moduleID,
             ModuleIdentifierArrayKind::HeaderInputDependencySourceFiles),
+        getSearchPathArrayID(moduleID),
         swiftBinDeps->isFramework, swiftBinDeps->isStatic,
+        swiftBinDeps->isBuiltWithCxxInterop,
         getIdentifier(swiftBinDeps->moduleCacheKey),
         getIdentifier(swiftBinDeps->userModuleVersion));
-
-    break;
-  }
-  case swift::ModuleDependencyKind::SwiftPlaceholder: {
-    auto swiftPHDeps = dependencyInfo.getAsPlaceholderDependencyModule();
-    assert(swiftPHDeps);
-    SwiftPlaceholderModuleDetailsLayout::emitRecord(
-        Out, ScratchRecord,
-        AbbrCodes[SwiftPlaceholderModuleDetailsLayout::Code],
-        getIdentifier(swiftPHDeps->compiledModulePath),
-        getIdentifier(swiftPHDeps->moduleDocPath),
-        getIdentifier(swiftPHDeps->sourceInfoPath));
     break;
   }
   case swift::ModuleDependencyKind::Clang: {
@@ -1708,6 +1768,15 @@ unsigned ModuleDependenciesCacheSerializer::getMacroDependenciesArrayID(
   return iter->second;
 }
 
+unsigned ModuleDependenciesCacheSerializer::getSearchPathArrayID(
+    ModuleDependencyID moduleID) const {
+  auto iter = SearchPathArrayIDsMap.find(moduleID);
+  if (iter == SearchPathArrayIDsMap.end())
+    return 0;
+
+  return iter->second;
+}
+
 unsigned ModuleDependenciesCacheSerializer::getImportStatementsArrayID(
     ModuleDependencyID moduleID) const {
   auto iter = ImportInfosArrayIDsMap.find(moduleID);
@@ -1732,20 +1801,14 @@ void ModuleDependenciesCacheSerializer::collectStringsAndArrays(
   for (auto kind = ModuleDependencyKind::FirstKind;
        kind != ModuleDependencyKind::LastKind; ++kind) {
     auto modMap = cache.getDependenciesMap(kind);
-    for (const auto &entry : modMap) {
-      ModuleDependencyID moduleID = {entry.getKey().str(), kind};
+    for (const auto &entry : modMap.keys()) {
+      ModuleDependencyID moduleID = {entry.str(), kind};
       auto optionalDependencyInfo = cache.findDependency(moduleID);
-      assert(optionalDependencyInfo.has_value() && "Expected dependency info.");
-      auto dependencyInfo = optionalDependencyInfo.value();
+      assert(optionalDependencyInfo && "Expected dependency info.");
+      auto dependencyInfo = *optionalDependencyInfo;
       // Add the module's name
       addIdentifier(moduleID.ModuleName);
 
-      // Map import infos to their respective module identifiers
-      auto importInfoArrayToIdentifier =
-          [](const auto &importInfo) -> std::string {
-        return importInfo.importIdentifier;
-      };
-
       for (const auto &ll : dependencyInfo->getLinkLibraries())
         addIdentifier(ll.getName().str());
 
@@ -1754,22 +1817,18 @@ void ModuleDependenciesCacheSerializer::collectStringsAndArrays(
         addIdentifier(md.second.LibraryPath);
         addIdentifier(md.second.ExecutablePath);
       }
+      
+      for (const auto &ii : dependencyInfo->getModuleImports()) {
+        addIdentifier(ii.importIdentifier);
+        for (const auto &il : ii.importLocations)
+          addIdentifier(il.bufferIdentifier);
+      }
 
-      // Add the module's imports
-      std::vector<std::string> importIdentifiers;
-      llvm::transform(dependencyInfo->getModuleImports(),
-                      std::back_inserter(importIdentifiers),
-                      importInfoArrayToIdentifier);
-      std::vector<std::string> optionalImportIdentifiers;
-      llvm::transform(dependencyInfo->getOptionalModuleImports(),
-                      std::back_inserter(optionalImportIdentifiers),
-                      importInfoArrayToIdentifier);
-
-      addStringArray(moduleID, ModuleIdentifierArrayKind::DependencyImports,
-                     importIdentifiers);
-      addStringArray(moduleID,
-                     ModuleIdentifierArrayKind::OptionalDependencyImports,
-                     optionalImportIdentifiers);
+      for (const auto &oii : dependencyInfo->getOptionalModuleImports()) {
+        addIdentifier(oii.importIdentifier);
+        for (const auto &oil : oii.importLocations)
+          addIdentifier(oil.bufferIdentifier);
+      }
 
       addDependencyIDArray(
           moduleID, ModuleIdentifierArrayKind::ImportedSwiftDependenciesIDs,
@@ -1785,9 +1844,6 @@ void ModuleDependenciesCacheSerializer::collectStringsAndArrays(
           moduleID, ModuleIdentifierArrayKind::SwiftOverlayDependenciesIDs,
           dependencyInfo->getSwiftOverlayDependencies());
 
-      addStringArray(moduleID, ModuleIdentifierArrayKind::AuxiliaryFileIDs,
-                     dependencyInfo->getAuxiliaryFiles());
-
       std::vector<std::string> clangHeaderDependencyNames;
       for (const auto &headerDepID :
            dependencyInfo->getHeaderClangDependencies())
@@ -1806,9 +1862,9 @@ void ModuleDependenciesCacheSerializer::collectStringsAndArrays(
         addStringArray(moduleID, ModuleIdentifierArrayKind::BuildCommandLine,
                        swiftTextDeps->textualModuleDetails.buildCommandLine);
         addIdentifier(swiftTextDeps->contextHash);
-        if (swiftTextDeps->textualModuleDetails.bridgingHeaderFile.has_value())
+        if (swiftTextDeps->textualModuleDetails.bridgingHeaderFile)
           addIdentifier(
-              swiftTextDeps->textualModuleDetails.bridgingHeaderFile.value());
+              *(swiftTextDeps->textualModuleDetails.bridgingHeaderFile));
         addStringArray(moduleID, ModuleIdentifierArrayKind::SourceFiles,
                        std::vector<std::string>());
         addStringArray(moduleID, ModuleIdentifierArrayKind::BridgingSourceFiles,
@@ -1842,23 +1898,16 @@ void ModuleDependenciesCacheSerializer::collectStringsAndArrays(
             moduleID,
             ModuleIdentifierArrayKind::HeaderInputDependencySourceFiles,
             swiftBinDeps->headerSourceFiles);
-        break;
-      }
-      case swift::ModuleDependencyKind::SwiftPlaceholder: {
-        auto swiftPHDeps = dependencyInfo->getAsPlaceholderDependencyModule();
-        assert(swiftPHDeps);
-        addIdentifier(swiftPHDeps->compiledModulePath);
-        addIdentifier(swiftPHDeps->moduleDocPath);
-        addIdentifier(swiftPHDeps->sourceInfoPath);
+        llvm::for_each(swiftBinDeps->serializedSearchPaths,
+                       [this](auto &sp) { addIdentifier(sp.Path); });
         break;
       }
       case swift::ModuleDependencyKind::SwiftSource: {
         auto swiftSourceDeps = dependencyInfo->getAsSwiftSourceModule();
         assert(swiftSourceDeps);
-        if (swiftSourceDeps->textualModuleDetails.bridgingHeaderFile
-                .has_value())
+        if (swiftSourceDeps->textualModuleDetails.bridgingHeaderFile)
           addIdentifier(
-              swiftSourceDeps->textualModuleDetails.bridgingHeaderFile.value());
+            *(swiftSourceDeps->textualModuleDetails.bridgingHeaderFile));
         addStringArray(moduleID, ModuleIdentifierArrayKind::SourceFiles,
                        swiftSourceDeps->sourceFiles);
         addStringArray(
@@ -1922,13 +1971,15 @@ void ModuleDependenciesCacheSerializer::writeInterModuleDependenciesCache(
   registerRecordAbbr<LinkLibraryArrayLayout>();
   registerRecordAbbr<MacroDependencyLayout>();
   registerRecordAbbr<MacroDependencyArrayLayout>();
+  registerRecordAbbr<SearchPathLayout>();
+  registerRecordAbbr<SearchPathArrayLayout>();
   registerRecordAbbr<ImportStatementLayout>();
   registerRecordAbbr<ImportStatementArrayLayout>();
+  registerRecordAbbr<OptionalImportStatementArrayLayout>();
   registerRecordAbbr<ModuleInfoLayout>();
   registerRecordAbbr<SwiftSourceModuleDetailsLayout>();
   registerRecordAbbr<SwiftInterfaceModuleDetailsLayout>();
   registerRecordAbbr<SwiftBinaryModuleDetailsLayout>();
-  registerRecordAbbr<SwiftPlaceholderModuleDetailsLayout>();
   registerRecordAbbr<ClangModuleDetailsLayout>();
 
   // Make a pass to collect all unique strings and arrays
@@ -1956,6 +2007,9 @@ void ModuleDependenciesCacheSerializer::writeInterModuleDependenciesCache(
   // Write all the arrays of macro dependency infos for this graph
   writeMacroDependencies(cache);
 
+  // Write all the arrays of binary-module-serialized search paths
+  writeSearchPaths(cache);
+
   // Write the core graph
   for (auto kind = ModuleDependencyKind::FirstKind;
        kind != ModuleDependencyKind::LastKind; ++kind) {
diff --git a/lib/DependencyScan/ModuleDependencyScanner.cpp b/lib/DependencyScan/ModuleDependencyScanner.cpp
index f032321f77371..5cd19423bf489 100644
--- a/lib/DependencyScan/ModuleDependencyScanner.cpp
+++ b/lib/DependencyScan/ModuleDependencyScanner.cpp
@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "swift/DependencyScan/ModuleDependencyScanner.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/DiagnosticEngine.h"
 #include "swift/AST/DiagnosticSuppression.h"
@@ -26,14 +27,16 @@
 #include "swift/Basic/FileTypes.h"
 #include "swift/Basic/PrettyStackTrace.h"
 #include "swift/ClangImporter/ClangImporter.h"
-#include "swift/DependencyScan/ModuleDependencyScanner.h"
 #include "swift/Frontend/CompileJobCacheKey.h"
 #include "swift/Frontend/ModuleInterfaceLoader.h"
+#include "swift/Serialization/ScanningLoaders.h"
 #include "swift/Serialization/SerializedModuleLoader.h"
 #include "swift/Subsystems.h"
+#include "clang/CAS/IncludeTree.h"
+#include "clang/Frontend/CompilerInstance.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/SetOperations.h"
-#include "llvm/CAS/CachingOnDiskFileSystem.h"
+#include "llvm/CAS/CASProvidingFileSystem.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/MemoryBufferRef.h"
@@ -72,7 +75,8 @@ static void findPath_dfs(ModuleDependencyID X, ModuleDependencyID Y,
         node->isClangModule())
       lookupKind = ModuleDependencyKind::Clang;
 
-    auto optionalDepNode = cache.findDependency(dep.importIdentifier, lookupKind);
+    auto optionalDepNode =
+        cache.findDependency(dep.importIdentifier, lookupKind);
     if (!optionalDepNode.has_value())
       continue;
     auto depNode = optionalDepNode.value();
@@ -100,95 +104,127 @@ findPathToDependency(ModuleDependencyID dependency,
   return dependencyPath;
 }
 
-// Diagnose scanner failure and attempt to reconstruct the dependency
-// path from the main module to the missing dependency.
-static void
-diagnoseScannerFailure(const ScannerImportStatementInfo &moduleImport,
-                       DiagnosticEngine &Diags,
-                       const ModuleDependenciesCache &cache,
-                       std::optional<ModuleDependencyID> dependencyOf) {
-  SourceLoc importLoc = SourceLoc();
-  if (!moduleImport.importLocations.empty()) {
-    auto locInfo = moduleImport.importLocations[0];
-    importLoc = Diags.SourceMgr.getLocFromExternalSource(locInfo.bufferIdentifier,
-                                                         locInfo.lineNumber,
-                                                         locInfo.columnNumber);
-  }
-
-  Diags.diagnose(importLoc, diag::dependency_scan_module_not_found,
-                 moduleImport.importIdentifier);
-  if (dependencyOf.has_value()) {
-    auto path = findPathToDependency(dependencyOf.value(), cache);
-    // We may fail to construct a path in some cases, such as a Swift overlay of
-    // a Clang module dependnecy.
-    if (path.empty())
-      path = {dependencyOf.value()};
-
-    for (auto it = path.rbegin(), end = path.rend(); it != end; ++it) {
-      const auto &entry = *it;
-      auto optionalEntryNode = cache.findDependency(entry);
-      assert(optionalEntryNode.has_value());
-      auto entryNode = optionalEntryNode.value();
-      std::string moduleFilePath = "";
-      bool isClang = false;
-      switch (entryNode->getKind()) {
-      case swift::ModuleDependencyKind::SwiftSource:
-        Diags.diagnose(importLoc, diag::dependency_as_imported_by_main_module,
-                       entry.ModuleName);
-        continue;
-      case swift::ModuleDependencyKind::SwiftInterface:
-        moduleFilePath =
-            entryNode->getAsSwiftInterfaceModule()->swiftInterfaceFile;
-        break;
-      case swift::ModuleDependencyKind::SwiftBinary:
-        moduleFilePath =
-            entryNode->getAsSwiftBinaryModule()->compiledModulePath;
-        break;
-      case swift::ModuleDependencyKind::SwiftPlaceholder:
-        moduleFilePath =
-            entryNode->getAsPlaceholderDependencyModule()->compiledModulePath;
-        break;
-      case swift::ModuleDependencyKind::Clang:
-        moduleFilePath = entryNode->getAsClangModule()->moduleMapFile;
-        isClang = true;
-        break;
-      default:
-        llvm_unreachable("Unexpected dependency kind");
-      }
+static bool isSwiftDependencyKind(ModuleDependencyKind Kind) {
+  return Kind == ModuleDependencyKind::SwiftInterface ||
+         Kind == ModuleDependencyKind::SwiftSource ||
+         Kind == ModuleDependencyKind::SwiftBinary;
+}
 
-      Diags.diagnose(importLoc, diag::dependency_as_imported_by,
-                     entry.ModuleName, moduleFilePath, isClang);
-    }
+// The Swift compiler does not have a concept of a working directory.
+// It is instead handled by the Swift driver by resolving relative paths
+// according to the driver's notion of a working directory. On the other hand,
+// Clang does have a concept working directory which may be specified on a
+// Clang invocation with '-working-directory'. If so, it is crucial that we
+// use this directory as an argument to the Clang scanner invocation below.
+static std::string
+computeClangWorkingDirectory(const std::vector<std::string> &commandLineArgs,
+                             const ASTContext &ctx) {
+  std::string workingDir;
+  auto clangWorkingDirPos = std::find(
+      commandLineArgs.rbegin(), commandLineArgs.rend(), "-working-directory");
+  if (clangWorkingDirPos == commandLineArgs.rend())
+    workingDir =
+        ctx.SourceMgr.getFileSystem()->getCurrentWorkingDirectory().get();
+  else {
+    if (clangWorkingDirPos - 1 == commandLineArgs.rend()) {
+      ctx.Diags.diagnose(SourceLoc(), diag::clang_dependency_scan_error,
+                         "Missing '-working-directory' argument");
+      workingDir =
+          ctx.SourceMgr.getFileSystem()->getCurrentWorkingDirectory().get();
+    } else
+      workingDir = *(clangWorkingDirPos - 1);
   }
+  return workingDir;
+}
 
-  if (moduleImport.importLocations.size() > 1) {
-    for (size_t i = 1; i < moduleImport.importLocations.size(); ++i) {
-      auto locInfo = moduleImport.importLocations[i];
-      auto importLoc = Diags.SourceMgr.getLocFromExternalSource(locInfo.bufferIdentifier,
-                                                                locInfo.lineNumber,
-                                                                locInfo.columnNumber);
-      Diags.diagnose(importLoc, diag::unresolved_import_location);
-    }
+std::string ModuleDependencyScanner::clangModuleOutputPathLookup(
+    const clang::tooling::dependencies::ModuleDeps &clangDeps,
+    clang::tooling::dependencies::ModuleOutputKind moduleOutputKind) const {
+  llvm::SmallString<128> outputPath(ModuleOutputPath);
+  if (clangDeps.IsInStableDirectories)
+    outputPath = SDKModuleOutputPath;
+
+  auto runtimeResourcePath = ScanASTContext.SearchPathOpts.RuntimeResourcePath;
+
+  // FIXME: This is a hack to treat Clang modules defined in the compiler's
+  // own resource directory as stable, when they are not reported as such
+  // by the Clang scanner.
+  if (!runtimeResourcePath.empty() &&
+      hasPrefix(llvm::sys::path::begin(clangDeps.ClangModuleMapFile),
+                llvm::sys::path::end(clangDeps.ClangModuleMapFile),
+                llvm::sys::path::begin(runtimeResourcePath),
+                llvm::sys::path::end(runtimeResourcePath)))
+    outputPath = SDKModuleOutputPath;
+
+  llvm::sys::path::append(outputPath, clangDeps.ID.ModuleName + "-" +
+                                          clangDeps.ID.ContextHash);
+  switch (moduleOutputKind) {
+  case clang::tooling::dependencies::ModuleOutputKind::ModuleFile:
+    llvm::sys::path::replace_extension(
+        outputPath, getExtension(swift::file_types::TY_ClangModuleFile));
+    break;
+  case clang::tooling::dependencies::ModuleOutputKind::DependencyFile:
+    llvm::sys::path::replace_extension(
+        outputPath, getExtension(swift::file_types::TY_Dependencies));
+    break;
+  case clang::tooling::dependencies::ModuleOutputKind::DependencyTargets:
+    return clangDeps.ID.ModuleName + "-" + clangDeps.ID.ContextHash;
+  case clang::tooling::dependencies::ModuleOutputKind::
+      DiagnosticSerializationFile:
+    llvm::sys::path::replace_extension(
+        outputPath, getExtension(swift::file_types::TY_SerializedDiagnostics));
+    break;
   }
+  return outputPath.str().str();
 }
 
-static bool isSwiftDependencyKind(ModuleDependencyKind Kind) {
-  return Kind == ModuleDependencyKind::SwiftInterface ||
-         Kind == ModuleDependencyKind::SwiftSource ||
-         Kind == ModuleDependencyKind::SwiftBinary ||
-         Kind == ModuleDependencyKind::SwiftPlaceholder;
+static std::vector<std::string> inputSpecificClangScannerCommand(
+    const std::vector<std::string> &baseCommandLineArgs,
+    std::optional<StringRef> sourceFileName) {
+  std::vector<std::string> result(baseCommandLineArgs.begin(),
+                                  baseCommandLineArgs.end());
+  auto sourceFilePos =
+      std::find(result.begin(), result.end(), "<swift-imported-modules>");
+  assert(sourceFilePos != result.end());
+  if (sourceFileName.has_value())
+    *sourceFilePos = sourceFileName->str();
+  else
+    result.erase(sourceFilePos);
+  return result;
+}
+
+static llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
+getClangScanningFS(std::shared_ptr<llvm::cas::ObjectStore> cas,
+                   ASTContext &ctx) {
+  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> baseFileSystem =
+      llvm::vfs::createPhysicalFileSystem();
+  ClangInvocationFileMapping fileMapping =
+    applyClangInvocationMapping(ctx, nullptr, baseFileSystem, false);
+
+  if (cas)
+    return llvm::cas::createCASProvidingFileSystem(cas, baseFileSystem);
+  return baseFileSystem;
 }
 
 ModuleDependencyScanningWorker::ModuleDependencyScanningWorker(
     SwiftDependencyScanningService &globalScanningService,
     const CompilerInvocation &ScanCompilerInvocation,
     const SILOptions &SILOptions, ASTContext &ScanASTContext,
-    swift::DependencyTracker &DependencyTracker, DiagnosticEngine &Diagnostics)
-    : clangScanningTool(*globalScanningService.ClangScanningService,
-                        globalScanningService.getClangScanningFS()) {
-  // Create a scanner-specific Invocation and ASTContext.
-  workerCompilerInvocation =
-      std::make_unique<CompilerInvocation>(ScanCompilerInvocation);
+    swift::DependencyTracker &DependencyTracker,
+    std::shared_ptr<llvm::cas::ObjectStore> CAS,
+    std::shared_ptr<llvm::cas::ActionCache> ActionCache,
+    llvm::PrefixMapper *Mapper, DiagnosticEngine &Diagnostics)
+    : workerCompilerInvocation(
+          std::make_unique<CompilerInvocation>(ScanCompilerInvocation)),
+      clangScanningTool(*globalScanningService.ClangScanningService,
+                        getClangScanningFS(CAS, ScanASTContext)),
+      CAS(CAS), ActionCache(ActionCache) {
+  // Instantiate a worker-specific diagnostic engine and copy over
+  // the scanner's diagnostic consumers (expected to be thread-safe).
+  workerDiagnosticEngine = std::make_unique<DiagnosticEngine>(ScanASTContext.SourceMgr);
+  for (auto &scannerDiagConsumer : Diagnostics.getConsumers())
+    workerDiagnosticEngine->addConsumer(*scannerDiagConsumer);
+
   workerASTContext = std::unique_ptr<ASTContext>(
       ASTContext::get(workerCompilerInvocation->getLangOptions(),
                       workerCompilerInvocation->getTypeCheckerOptions(),
@@ -198,66 +234,132 @@ ModuleDependencyScanningWorker::ModuleDependencyScanningWorker(
                       workerCompilerInvocation->getSymbolGraphOptions(),
                       workerCompilerInvocation->getCASOptions(),
                       workerCompilerInvocation->getSerializationOptions(),
-                      ScanASTContext.SourceMgr, Diagnostics));
+                      ScanASTContext.SourceMgr, *workerDiagnosticEngine));
+
+  scanningASTDelegate = std::make_unique<InterfaceSubContextDelegateImpl>(
+      workerASTContext->SourceMgr, workerDiagnosticEngine.get(),
+      workerASTContext->SearchPathOpts, workerASTContext->LangOpts,
+      workerASTContext->ClangImporterOpts, workerASTContext->CASOpts,
+      workerCompilerInvocation->getFrontendOptions(),
+      /* buildModuleCacheDirIfAbsent */ false,
+      getModuleCachePathFromClang(
+          ScanASTContext.getClangModuleLoader()->getClangInstance()),
+      workerCompilerInvocation->getFrontendOptions()
+          .PrebuiltModuleCachePath,
+      workerCompilerInvocation->getFrontendOptions()
+          .BackupModuleInterfaceDir,
+      workerCompilerInvocation->getFrontendOptions().CacheReplayPrefixMap,
+      workerCompilerInvocation->getFrontendOptions()
+          .SerializeModuleInterfaceDependencyHashes,
+      workerCompilerInvocation->getFrontendOptions()
+          .shouldTrackSystemDependencies()
+      );
+
   auto loader = std::make_unique<PluginLoader>(
       *workerASTContext, /*DepTracker=*/nullptr,
+      workerCompilerInvocation->getFrontendOptions().CacheReplayPrefixMap,
       workerCompilerInvocation->getFrontendOptions().DisableSandbox);
   workerASTContext->setPluginLoader(std::move(loader));
 
-  // Configure the interface scanning AST delegate.
-  auto ClangModuleCachePath = getModuleCachePathFromClang(
-      ScanASTContext.getClangModuleLoader()->getClangInstance());
-  auto &FEOpts = workerCompilerInvocation->getFrontendOptions();
-  scanningASTDelegate = std::make_unique<InterfaceSubContextDelegateImpl>(
-      workerASTContext->SourceMgr, &workerASTContext->Diags,
-      workerASTContext->SearchPathOpts, workerASTContext->LangOpts,
-      workerASTContext->ClangImporterOpts, workerASTContext->CASOpts, FEOpts,
-      /*buildModuleCacheDirIfAbsent*/ false, ClangModuleCachePath,
-      FEOpts.PrebuiltModuleCachePath, FEOpts.BackupModuleInterfaceDir,
-      FEOpts.SerializeModuleInterfaceDependencyHashes,
-      FEOpts.shouldTrackSystemDependencies(), RequireOSSAModules_t(SILOptions));
-
-  // Set up CAS instance.
-  CAS = globalScanningService.CAS;
-  ActionCache = globalScanningService.ActionCache;
-
-  // Set up the ClangImporter.
-  clangScannerModuleLoader = ClangImporter::create(
-      *workerASTContext, workerCompilerInvocation->getPCHHash(),
-      &DependencyTracker);
-  if (!clangScannerModuleLoader)
-    Diagnostics.diagnose(SourceLoc(), diag::error_clang_importer_create_fail);
-
-  // Set up the Swift interface loader for Swift scanning.
-  swiftScannerModuleLoader = ModuleInterfaceLoader::create(
+  // Set up the required command-line arguments and working directory
+  // configuration required for clang dependency scanner queries
+  auto scanClangImporter =
+      static_cast<ClangImporter *>(ScanASTContext.getClangModuleLoader());
+  clangScanningBaseCommandLineArgs =
+      scanClangImporter->getClangDepScanningInvocationArguments(ScanASTContext);
+  clangScanningModuleCommandLineArgs = inputSpecificClangScannerCommand(
+      clangScanningBaseCommandLineArgs, std::nullopt);
+  clangScanningWorkingDirectoryPath = computeClangWorkingDirectory(
+      clangScanningBaseCommandLineArgs, ScanASTContext);
+
+  // Handle clang arguments. For caching build, all arguments are passed
+  // with `-direct-clang-cc1-module-build`.
+  if (ScanASTContext.ClangImporterOpts.ClangImporterDirectCC1Scan) {
+    swiftModuleClangCC1CommandLineArgs.push_back(
+        "-direct-clang-cc1-module-build");
+    for (auto &Arg : scanClangImporter->getSwiftExplicitModuleDirectCC1Args()) {
+      swiftModuleClangCC1CommandLineArgs.push_back("-Xcc");
+      swiftModuleClangCC1CommandLineArgs.push_back(Arg);
+    }
+  } else {
+    swiftModuleClangCC1CommandLineArgs.push_back("-Xcc");
+    swiftModuleClangCC1CommandLineArgs.push_back("-fno-implicit-modules");
+    swiftModuleClangCC1CommandLineArgs.push_back("-Xcc");
+    swiftModuleClangCC1CommandLineArgs.push_back("-fno-implicit-module-maps");
+  }
+
+  // Set up the Swift module loader for Swift queries.
+  swiftModuleScannerLoader = std::make_unique<SwiftModuleScanner>(
       *workerASTContext,
-      *static_cast<ModuleInterfaceCheckerImpl *>(
-          ScanASTContext.getModuleInterfaceChecker()),
-      &DependencyTracker,
-      workerCompilerInvocation->getSearchPathOptions().ModuleLoadMode);
+      workerCompilerInvocation->getSearchPathOptions().ModuleLoadMode,
+      *scanningASTDelegate, swiftModuleClangCC1CommandLineArgs,
+      workerCompilerInvocation->getSearchPathOptions().ExplicitSwiftModuleInputs);
 }
 
-ModuleDependencyVector
+SwiftModuleScannerQueryResult
 ModuleDependencyScanningWorker::scanFilesystemForSwiftModuleDependency(
-    Identifier moduleName, StringRef moduleOutputPath,
-    StringRef sdkModuleOutputPath, llvm::PrefixMapper *prefixMapper,
-    bool isTestableImport) {
-  return swiftScannerModuleLoader->getModuleDependencies(
-      moduleName, moduleOutputPath, sdkModuleOutputPath,
-      {}, clangScanningTool, *scanningASTDelegate,
-      prefixMapper, isTestableImport);
+    Identifier moduleName, bool isTestableImport) {
+  return swiftModuleScannerLoader->lookupSwiftModule(moduleName,
+                                                     isTestableImport);
 }
 
-ModuleDependencyVector
+std::optional<clang::tooling::dependencies::TranslationUnitDeps>
 ModuleDependencyScanningWorker::scanFilesystemForClangModuleDependency(
-    Identifier moduleName, StringRef moduleOutputPath,
-    StringRef sdkModuleOutputPath,
-    const llvm::DenseSet<clang::tooling::dependencies::ModuleID> &alreadySeenModules,
-    llvm::PrefixMapper *prefixMapper) {
-  return clangScannerModuleLoader->getModuleDependencies(
-      moduleName, moduleOutputPath, sdkModuleOutputPath,
-      alreadySeenModules, clangScanningTool,
-      *scanningASTDelegate, prefixMapper, false);
+    Identifier moduleName,
+    LookupModuleOutputCallback lookupModuleOutput,
+    const llvm::DenseSet<clang::tooling::dependencies::ModuleID>
+        &alreadySeenModules) {
+  auto clangModuleDependencies = clangScanningTool.getModuleDependencies(
+      moduleName.str(), clangScanningModuleCommandLineArgs,
+      clangScanningWorkingDirectoryPath, alreadySeenModules,
+      lookupModuleOutput);
+  if (!clangModuleDependencies) {
+    llvm::handleAllErrors(clangModuleDependencies.takeError(), [this, &moduleName](
+                                                  const llvm::StringError &E) {
+          auto &message = E.getMessage();
+          if (message.find("fatal error: module '" + moduleName.str().str() +
+                            "' not found") == std::string::npos)
+            workerDiagnosticEngine->diagnose(SourceLoc(), diag::clang_dependency_scan_error, message);
+      });
+    return std::nullopt;
+  }
+
+  return clangModuleDependencies.get();
+}
+
+std::optional<clang::tooling::dependencies::TranslationUnitDeps>
+ModuleDependencyScanningWorker::scanHeaderDependenciesOfSwiftModule(
+    ModuleDependencyID moduleID,
+    std::optional<StringRef> headerPath,
+    std::optional<llvm::MemoryBufferRef> sourceBuffer,
+    LookupModuleOutputCallback lookupModuleOutput,
+    const llvm::DenseSet<clang::tooling::dependencies::ModuleID>
+       &alreadySeenModules) {
+  // Scan the specified textual header file and collect its dependencies
+  auto scanHeaderDependencies = [&]()
+      -> llvm::Expected<clang::tooling::dependencies::TranslationUnitDeps> {
+    auto dependencies = clangScanningTool.getTranslationUnitDependencies(
+        inputSpecificClangScannerCommand(clangScanningBaseCommandLineArgs,
+                                         headerPath),
+        clangScanningWorkingDirectoryPath, alreadySeenModules,
+        lookupModuleOutput, sourceBuffer);
+    if (!dependencies)
+      return dependencies.takeError();
+    return dependencies;
+  };
+
+  // - If a generated header is provided, scan the generated header.
+  // - Textual module dependencies require us to process their bridging header.
+  // - Binary module dependnecies may have arbitrary header inputs.
+  auto clangModuleDependencies = scanHeaderDependencies();
+  if (!clangModuleDependencies) {
+    auto errorStr = toString(clangModuleDependencies.takeError());
+    workerDiagnosticEngine->diagnose(
+        SourceLoc(), diag::clang_header_dependency_scan_error, errorStr);
+    return std::nullopt;
+  }
+
+  return *clangModuleDependencies;
 }
 
 template <typename Function, typename... Args>
@@ -313,46 +415,167 @@ llvm::Error ModuleDependencyScanningWorker::createCacheKeyForEmbeddedHeader(
   return ActionCache->put(CAS->getID(*key), *embedded);
 }
 
-Identifier ModuleDependencyScanner::getModuleImportIdentifier(StringRef moduleName) {
+Identifier
+ModuleDependencyScanner::getModuleImportIdentifier(StringRef moduleName) {
   return ScanASTContext.getIdentifier(moduleName);
 }
 
+SwiftDependencyTracker::SwiftDependencyTracker(
+    std::shared_ptr<llvm::cas::ObjectStore> CAS, llvm::PrefixMapper *Mapper,
+    const CompilerInvocation &CI)
+    : CAS(CAS), Mapper(Mapper) {
+  auto &SearchPathOpts = CI.getSearchPathOptions();
+
+  FS = llvm::cas::createCASProvidingFileSystem(
+      CAS, llvm::vfs::createPhysicalFileSystem());
+
+  auto addCommonFile = [&](StringRef path) {
+    auto file = FS->openFileForRead(path);
+    if (!file)
+      return;
+    auto status = (*file)->status();
+    if (!status)
+      return;
+    auto fileRef = (*file)->getObjectRefForContent();
+    if (!fileRef)
+      return;
+
+    std::string realPath = Mapper ? Mapper->mapToString(path) : path.str();
+    CommonFiles.try_emplace(realPath, **fileRef, (size_t)status->getSize());
+  };
+
+  // Add SDKSetting file.
+  SmallString<256> SDKSettingPath;
+  llvm::sys::path::append(SDKSettingPath, SearchPathOpts.getSDKPath(),
+                          "SDKSettings.json");
+  addCommonFile(SDKSettingPath);
+
+  // Add Legacy layout file.
+  const std::vector<std::string> AllSupportedArches = {
+      "arm64", "arm64e", "x86_64", "i386",
+      "armv7", "armv7s", "armv7k", "arm64_32"};
+
+  for (auto RuntimeLibPath : SearchPathOpts.RuntimeLibraryPaths) {
+    std::error_code EC;
+    for (auto &Arch : AllSupportedArches) {
+      SmallString<256> LayoutFile(RuntimeLibPath);
+      llvm::sys::path::append(LayoutFile, "layouts-" + Arch + ".yaml");
+      addCommonFile(LayoutFile);
+    }
+  }
+
+  // Add VFSOverlay file.
+  for (auto &Overlay: SearchPathOpts.VFSOverlayFiles)
+    addCommonFile(Overlay);
+
+  // Add blocklist file.
+  for (auto &File: CI.getFrontendOptions().BlocklistConfigFilePaths)
+    addCommonFile(File);
+
+  // Add access notes.
+  StringRef AccessNotePath = CI.getLangOptions().AccessNotesPath;
+  if (!AccessNotePath.empty())
+    addCommonFile(AccessNotePath);
+}
+
+void SwiftDependencyTracker::startTracking(bool includeCommonDeps) {
+  TrackedFiles.clear();
+  if (includeCommonDeps) {
+    for (auto &entry : CommonFiles)
+      TrackedFiles.emplace(entry.first(), entry.second);
+  }
+}
+
+void SwiftDependencyTracker::trackFile(const Twine &path) {
+  auto file = FS->openFileForRead(path);
+  if (!file)
+    return;
+  auto status = (*file)->status();
+  if (!status)
+    return;
+  auto fileRef = (*file)->getObjectRefForContent();
+  if (!fileRef)
+    return;
+  std::string realPath =
+      Mapper ? Mapper->mapToString(path.str()) : path.str();
+  TrackedFiles.try_emplace(realPath, **fileRef, (size_t)status->getSize());
+}
+
+llvm::Expected<llvm::cas::ObjectProxy>
+SwiftDependencyTracker::createTreeFromDependencies() {
+  llvm::SmallVector<clang::cas::IncludeTree::FileList::FileEntry> Files;
+  for (auto &file : TrackedFiles) {
+    auto includeTreeFile = clang::cas::IncludeTree::File::create(
+        *CAS, file.first, file.second.FileRef);
+    if (!includeTreeFile) {
+      return llvm::createStringError("CASFS createTree failed for " +
+                                     file.first + ": " +
+                                     toString(includeTreeFile.takeError()));
+    }
+    Files.push_back(
+        {includeTreeFile->getRef(),
+         (clang::cas::IncludeTree::FileList::FileSizeTy)file.second.Size});
+  }
+
+  auto includeTreeList =
+      clang::cas::IncludeTree::FileList::create(*CAS, Files, {});
+  if (!includeTreeList)
+    return llvm::createStringError("casfs include-tree filelist error: " +
+                                   toString(includeTreeList.takeError()));
+
+  return *includeTreeList;
+}
+
 ModuleDependencyScanner::ModuleDependencyScanner(
     SwiftDependencyScanningService &ScanningService,
     const CompilerInvocation &ScanCompilerInvocation,
     const SILOptions &SILOptions, ASTContext &ScanASTContext,
-    swift::DependencyTracker &DependencyTracker, DiagnosticEngine &Diagnostics,
-    bool ParallelScan)
+    swift::DependencyTracker &DependencyTracker,
+    std::shared_ptr<llvm::cas::ObjectStore> CAS,
+    std::shared_ptr<llvm::cas::ActionCache> ActionCache,
+    DiagnosticEngine &Diagnostics, bool ParallelScan)
     : ScanCompilerInvocation(ScanCompilerInvocation),
-      ScanASTContext(ScanASTContext), Diagnostics(Diagnostics),
+      ScanASTContext(ScanASTContext), IssueReporter(Diagnostics),
+      ModuleOutputPath(ScanCompilerInvocation.getFrontendOptions()
+                       .ExplicitModulesOutputPath),
+      SDKModuleOutputPath(ScanCompilerInvocation.getFrontendOptions()
+                          .ExplicitSDKModulesOutputPath),
       NumThreads(ParallelScan
                      ? llvm::hardware_concurrency().compute_thread_count()
                      : 1),
-      ScanningThreadPool(llvm::hardware_concurrency(NumThreads)) {
+      ScanningThreadPool(llvm::hardware_concurrency(NumThreads)), CAS(CAS),
+      ActionCache(ActionCache) {
+  // Setup prefix mapping.
+  auto &ScannerPrefixMapper =
+      ScanCompilerInvocation.getSearchPathOptions().ScannerPrefixMapper;
+  if (!ScannerPrefixMapper.empty()) {
+    PrefixMapper = std::make_unique<llvm::PrefixMapper>();
+    SmallVector<llvm::MappedPrefix, 4> Prefixes;
+    llvm::MappedPrefix::transformPairs(ScannerPrefixMapper, Prefixes);
+    PrefixMapper->addRange(Prefixes);
+    PrefixMapper->sort();
+  }
+
+  if (CAS)
+    CacheFS = llvm::cas::createCASProvidingFileSystem(
+        CAS, ScanASTContext.SourceMgr.getFileSystem());
+
   // TODO: Make num threads configurable
   for (size_t i = 0; i < NumThreads; ++i)
     Workers.emplace_front(std::make_unique<ModuleDependencyScanningWorker>(
         ScanningService, ScanCompilerInvocation, SILOptions, ScanASTContext,
-        DependencyTracker, Diagnostics));
+        DependencyTracker, CAS, ActionCache, PrefixMapper.get(), Diagnostics));
 }
 
-/// Find all of the imported Clang modules starting with the given module name.
-static void findAllImportedClangModules(StringRef moduleName,
-                                        ModuleDependenciesCache &cache,
-                                        std::vector<std::string> &allModules,
-                                        llvm::StringSet<> &knownModules) {
-  if (!knownModules.insert(moduleName).second)
-    return;
-  allModules.push_back(moduleName.str());
-  auto moduleID = ModuleDependencyID{moduleName.str(),
-                                     ModuleDependencyKind::Clang};
-  auto optionalDependencies = cache.findDependency(moduleID);
-  if (!optionalDependencies.has_value())
-    return;
-
-  for (const auto &dep : cache.getClangDependencies(moduleID))
-    findAllImportedClangModules(dep.ModuleName, cache, allModules,
-                                knownModules);
+static std::set<ModuleDependencyID>
+collectBinarySwiftDeps(const ModuleDependenciesCache &cache) {
+  std::set<ModuleDependencyID> binarySwiftModuleDepIDs;
+  auto binaryDepsMap =
+      cache.getDependenciesMap(ModuleDependencyKind::SwiftBinary);
+  for (const auto &binaryDepName : binaryDepsMap.keys())
+    binarySwiftModuleDepIDs.insert(ModuleDependencyID{
+        binaryDepName.str(), ModuleDependencyKind::SwiftBinary});
+  return binarySwiftModuleDepIDs;
 }
 
 llvm::ErrorOr<ModuleDependencyInfo>
@@ -384,16 +607,8 @@ ModuleDependencyScanner::getMainModuleDependencyInfo(ModuleDecl *mainModule) {
     buildCommands.emplace_back(arg);
   });
 
-  auto mainDependencies = ModuleDependencyInfo::forSwiftSourceModule(
-       {}, buildCommands, {}, {}, {});
-
-  if (ScanASTContext.CASOpts.EnableCaching) {
-    std::vector<std::string> clangDependencyFiles;
-    clangImporter->addClangInvovcationDependencies(clangDependencyFiles);
-    llvm::for_each(clangDependencyFiles, [&](std::string &file) {
-      mainDependencies.addAuxiliaryFile(file);
-    });
-  }
+  auto mainDependencies =
+      ModuleDependencyInfo::forSwiftSourceModule({}, buildCommands, {}, {}, {});
 
   llvm::StringSet<> alreadyAddedModules;
   // Compute Implicit dependencies of the main module
@@ -406,24 +621,25 @@ ModuleDependencyScanner::getMainModuleDependencyInfo(ModuleDecl *mainModule) {
       break;
 
     case ImplicitStdlibKind::Stdlib:
-      mainDependencies.addModuleImport("Swift", /* isExported */false,
+      mainDependencies.addModuleImport("Swift", /* isExported */ false,
+                                       AccessLevel::Public,
                                        &alreadyAddedModules);
       break;
     }
 
     // Add any implicit module names.
     for (const auto &import : importInfo.AdditionalUnloadedImports) {
-      mainDependencies.addModuleImport(import.module.getModulePath(),
-                                       import.options.contains(ImportFlags::Exported),
-                                       &alreadyAddedModules,
-                                       &ScanASTContext.SourceMgr);
+      mainDependencies.addModuleImport(
+          import.module.getModulePath(),
+          import.options.contains(ImportFlags::Exported), import.accessLevel,
+          &alreadyAddedModules, &ScanASTContext.SourceMgr);
     }
 
     // Already-loaded, implicitly imported module names.
     for (const auto &import : importInfo.AdditionalImports) {
       mainDependencies.addModuleImport(
           import.module.importedModule->getNameStr(),
-          import.options.contains(ImportFlags::Exported),
+          import.options.contains(ImportFlags::Exported), import.accessLevel,
           &alreadyAddedModules);
     }
 
@@ -435,9 +651,9 @@ ModuleDependencyScanner::getMainModuleDependencyInfo(ModuleDecl *mainModule) {
     // If we are to import the underlying Clang module of the same name,
     // add a dependency with the same name to trigger the search.
     if (importInfo.ShouldImportUnderlyingModule) {
-      mainDependencies.addModuleImport(mainModule->getName().str(),
-                                       /* isExported */ true,
-                                       &alreadyAddedModules);
+      mainDependencies.addModuleImport(
+          mainModule->getName().str(),
+          /* isExported */ true, AccessLevel::Public, &alreadyAddedModules);
     }
 
     // All modules specified with `-embed-tbd-for-module` are treated as
@@ -445,9 +661,9 @@ ModuleDependencyScanner::getMainModuleDependencyInfo(ModuleDecl *mainModule) {
     // to be impored in the source.
     for (const auto &tbdSymbolModule :
          ScanCompilerInvocation.getTBDGenOptions().embedSymbolsFromModules) {
-      mainDependencies.addModuleImport(tbdSymbolModule,
-                                       /* isExported */ false,
-                                       &alreadyAddedModules);
+      mainDependencies.addModuleImport(
+          tbdSymbolModule,
+          /* isExported */ false, AccessLevel::Public, &alreadyAddedModules);
     }
   }
 
@@ -458,8 +674,7 @@ ModuleDependencyScanner::getMainModuleDependencyInfo(ModuleDecl *mainModule) {
       if (!sourceFile)
         continue;
 
-      mainDependencies.addModuleImports(*sourceFile,
-                                        alreadyAddedModules,
+      mainDependencies.addModuleImports(*sourceFile, alreadyAddedModules,
                                         &ScanASTContext.SourceMgr);
     }
 
@@ -467,7 +682,7 @@ ModuleDependencyScanner::getMainModuleDependencyInfo(ModuleDecl *mainModule) {
     // build command to main module to ensure frontend gets the same result.
     // This needs to happen after visiting all the top-level decls from all
     // SourceFiles.
-    auto buildArgs = mainDependencies.getCommandline();
+    std::vector<std::string> buildArgs = mainDependencies.getCommandline();
     mainModule->getASTContext().forEachCanImportVersionCheck(
         [&](StringRef moduleName, const llvm::VersionTuple &Version,
             const llvm::VersionTuple &UnderlyingVersion) {
@@ -487,88 +702,6 @@ ModuleDependencyScanner::getMainModuleDependencyInfo(ModuleDecl *mainModule) {
   return mainDependencies;
 }
 
-/// Retrieve the module dependencies for the Clang module with the given name.
-std::optional<const ModuleDependencyInfo *>
-ModuleDependencyScanner::getNamedClangModuleDependencyInfo(
-    StringRef moduleName, ModuleDependenciesCache &cache,
-    ModuleDependencyIDSetVector &discoveredClangModules) {
-  // Check whether we've cached this result.
-  auto moduleID = ModuleDependencyID{moduleName.str(),
-                                     ModuleDependencyKind::Clang};
-  if (auto found = cache.findDependency(moduleID)) {
-    discoveredClangModules.insert(moduleID);
-    auto directClangDeps = cache.getImportedClangDependencies(moduleID);
-    ModuleDependencyIDSetVector reachableClangModules;
-    reachableClangModules.insert(directClangDeps.begin(),
-                                 directClangDeps.end());
-    for (unsigned currentModuleIdx = 0;
-         currentModuleIdx < reachableClangModules.size();
-         ++currentModuleIdx) {
-      auto moduleID = reachableClangModules[currentModuleIdx];
-      auto dependencies =
-        cache.findKnownDependency(moduleID).getImportedClangDependencies();
-      reachableClangModules.insert(dependencies.begin(), dependencies.end());
-    }
-    discoveredClangModules.insert(reachableClangModules.begin(),
-                                  reachableClangModules.end());
-    return found;
-  }
-
-  // Otherwise perform filesystem scan
-  auto moduleIdentifier = getModuleImportIdentifier(moduleName);
-  auto moduleDependencies = withDependencyScanningWorker(
-      [&cache, moduleIdentifier](ModuleDependencyScanningWorker *ScanningWorker) {
-        return ScanningWorker->scanFilesystemForClangModuleDependency(
-          moduleIdentifier, cache.getModuleOutputPath(),
-          cache.getSDKModuleOutputPath(),
-          cache.getAlreadySeenClangModules(),
-          cache.getScanService().getPrefixMapper());
-      });
-  if (moduleDependencies.empty())
-    return std::nullopt;
-
-  discoveredClangModules.insert(moduleID);
-  for (const auto &dep : moduleDependencies)
-    discoveredClangModules.insert(dep.first);
-
-  cache.recordDependencies(moduleDependencies);
-  return cache.findDependency(moduleID);
-}
-
-/// Retrieve the module dependencies for the Swift module with the given name.
-std::optional<const ModuleDependencyInfo *>
-ModuleDependencyScanner::getNamedSwiftModuleDependencyInfo(
-    StringRef moduleName, ModuleDependenciesCache &cache) {
-  // Check whether we've cached this result.
-  if (auto found =
-          cache.findDependency(moduleName, ModuleDependencyKind::SwiftSource))
-    return found;
-  if (auto found = cache.findDependency(moduleName,
-                                        ModuleDependencyKind::SwiftInterface))
-    return found;
-  if (auto found =
-          cache.findDependency(moduleName, ModuleDependencyKind::SwiftBinary))
-    return found;
-  if (auto found = cache.findDependency(moduleName,
-                                        ModuleDependencyKind::SwiftPlaceholder))
-    return found;
-
-  // Otherwise perform filesystem scan
-  auto moduleIdentifier = getModuleImportIdentifier(moduleName);
-  auto moduleDependencies = withDependencyScanningWorker(
-      [&cache, moduleIdentifier](ModuleDependencyScanningWorker *ScanningWorker) {
-        return ScanningWorker->scanFilesystemForSwiftModuleDependency(
-          moduleIdentifier, cache.getModuleOutputPath(),
-          cache.getSDKModuleOutputPath(),
-          cache.getScanService().getPrefixMapper());
-      });
-  if (moduleDependencies.empty())
-    return std::nullopt;
-
-  cache.recordDependencies(moduleDependencies);
-  return cache.findDependency(moduleName);
-}
-
 /// For the dependency set of the main module, discover all
 /// cross-import overlays and their corresponding '.swiftcrossimport'
 /// files. Cross-import overlay dependencies are required when
@@ -606,7 +739,8 @@ static void discoverCrossImportOverlayFiles(
   auto getModuleIDForImportIdentifier =
       [](const std::string &importIdentifierStr,
          const ModuleDependencyIDSet &directSwiftDepsSet,
-         const ModuleDependencyIDSet &directClangDepsSet) -> std::optional<ModuleDependencyID> {
+         const ModuleDependencyIDSet &directClangDepsSet)
+      -> std::optional<ModuleDependencyID> {
     if (auto textualDepIt = directSwiftDepsSet.find(
             {importIdentifierStr, ModuleDependencyKind::SwiftInterface});
         textualDepIt != directSwiftDepsSet.end())
@@ -632,7 +766,7 @@ static void discoverCrossImportOverlayFiles(
     if (importResolvedModuleID)
       for (const auto &importLocation : import.importLocations)
         perSourceFileDependencies[importLocation.bufferIdentifier].insert(
-          *importResolvedModuleID);
+            *importResolvedModuleID);
   }
 
   // For each source-file, build a set of module dependencies of the
@@ -721,15 +855,14 @@ static void discoverCrossImportOverlayFiles(
 }
 
 std::vector<ModuleDependencyID>
-ModuleDependencyScanner::performDependencyScan(
-    ModuleDependencyID rootModuleID, ModuleDependenciesCache &cache) {
+ModuleDependencyScanner::performDependencyScan(ModuleDependencyID rootModuleID,
+                                               ModuleDependenciesCache &cache) {
   PrettyStackTraceStringAction trace("Performing dependency scan of: ",
                                      rootModuleID.ModuleName);
   // If scanning for an individual Clang module, simply resolve its imports
   if (rootModuleID.Kind == ModuleDependencyKind::Clang) {
     ModuleDependencyIDSetVector discoveredClangModules;
-    resolveAllClangModuleDependencies({},
-                                      cache, discoveredClangModules);
+    resolveAllClangModuleDependencies({}, cache, discoveredClangModules);
     return discoveredClangModules.takeVector();
   }
 
@@ -745,8 +878,8 @@ ModuleDependencyScanner::performDependencyScan(
 
   // 5. Resolve cross-import overlays
   // This must only be done for the main source module, since textual and
-  // binary Swift modules already encode their dependencies on cross-import overlays
-  // with explicit imports.
+  // binary Swift modules already encode their dependencies on cross-import
+  // overlays with explicit imports.
   if (ScanCompilerInvocation.getLangOptions().EnableCrossImportOverlays)
     resolveCrossImportOverlayDependencies(
         rootModuleID.ModuleName, cache,
@@ -755,8 +888,9 @@ ModuleDependencyScanner::performDependencyScan(
   if (ScanCompilerInvocation.getSearchPathOptions().BridgingHeaderChaining) {
     auto err = performBridgingHeaderChaining(rootModuleID, cache, allModules);
     if (err)
-      Diagnostics.diagnose(SourceLoc(), diag::error_scanner_extra,
-                           toString(std::move(err)));
+      IssueReporter.Diagnostics.diagnose(SourceLoc(),
+                                         diag::error_scanner_extra,
+                                         toString(std::move(err)));
   }
 
   return allModules.takeVector();
@@ -765,9 +899,10 @@ ModuleDependencyScanner::performDependencyScan(
 ModuleDependencyIDSetVector
 ModuleDependencyScanner::resolveImportedModuleDependencies(
     const ModuleDependencyID &rootModuleID, ModuleDependenciesCache &cache) {
-  PrettyStackTraceStringAction trace("Resolving transitive closure of dependencies of: ",
-                                     rootModuleID.ModuleName);
   ModuleDependencyIDSetVector allModules;
+  PrettyStackTraceStringAction trace(
+      "Resolving transitive closure of dependencies of: ",
+      rootModuleID.ModuleName);
 
   // Resolve all imports for which a Swift module can be found,
   // transitively, starting at 'rootModuleID'.
@@ -776,33 +911,35 @@ ModuleDependencyScanner::resolveImportedModuleDependencies(
   allModules.insert(discoveredSwiftModules.begin(),
                     discoveredSwiftModules.end());
 
-  ModuleDependencyIDSetVector discoveredClangModules;
-  resolveAllClangModuleDependencies(discoveredSwiftModules.getArrayRef(),
-                                    cache, discoveredClangModules);
-  allModules.insert(discoveredClangModules.begin(),
-                    discoveredClangModules.end());
-
-  ModuleDependencyIDSetVector discoveredHeaderDependencyClangModules;
+  // Resolve all remaining unresolved imports for which no Swift
+  // module could be found, assuming them to be Clang modules.
+  // This operation is done by gathering all unresolved import
+  // identifiers and querying them in-parallel to the Clang
+  // dependency scanner.
+  resolveAllClangModuleDependencies(discoveredSwiftModules.getArrayRef(), cache,
+                                    allModules);
+
+  // For each discovered Swift module which was built with a
+  // bridging header, scan the header for module dependencies.
+  // This includes the source module bridging header.
   resolveHeaderDependencies(discoveredSwiftModules.getArrayRef(), cache,
-                            discoveredHeaderDependencyClangModules);
-  allModules.insert(discoveredHeaderDependencyClangModules.begin(),
-                    discoveredHeaderDependencyClangModules.end());
+                            allModules);
 
-  ModuleDependencyIDSetVector discoveredSwiftOverlayDependencyModules;
+  // For each Swift module which imports Clang modules,
+  // query whether all visible Clang dependencies from such imports
+  // have a Swift overaly module.
   resolveSwiftOverlayDependencies(discoveredSwiftModules.getArrayRef(), cache,
-                                  discoveredSwiftOverlayDependencyModules);
-  allModules.insert(discoveredSwiftOverlayDependencyModules.begin(),
-                    discoveredSwiftOverlayDependencyModules.end());
+                                  allModules);
 
   return allModules;
 }
 
-void
-ModuleDependencyScanner::resolveSwiftModuleDependencies(
+void ModuleDependencyScanner::resolveSwiftModuleDependencies(
     const ModuleDependencyID &rootModuleID, ModuleDependenciesCache &cache,
     ModuleDependencyIDSetVector &allDiscoveredSwiftModules) {
-  PrettyStackTraceStringAction trace("Resolving transitive closure of Swift dependencies of: ",
-                                     rootModuleID.ModuleName);
+  PrettyStackTraceStringAction trace(
+      "Resolving transitive closure of Swift dependencies of: ",
+      rootModuleID.ModuleName);
   // Clang modules cannot have Swift module dependencies
   if (!isSwiftDependencyKind(rootModuleID.Kind))
     return;
@@ -817,10 +954,12 @@ ModuleDependencyScanner::resolveSwiftModuleDependencies(
     // If this dependency module's Swift imports are already resolved,
     // we do not need to scan it.
     if (!moduleDependencyInfo.getImportedSwiftDependencies().empty()) {
-      for (const auto &dep : moduleDependencyInfo.getImportedSwiftDependencies())
+      for (const auto &dep :
+           moduleDependencyInfo.getImportedSwiftDependencies())
         allDiscoveredSwiftModules.insert(dep);
     } else {
-      // Find the Swift dependencies of every module this module directly depends on.
+      // Find the Swift dependencies of every module this module directly
+      // depends on.
       ModuleDependencyIDSetVector importedSwiftDependencies;
       resolveSwiftImportsForModule(moduleID, cache, importedSwiftDependencies);
       allDiscoveredSwiftModules.insert(importedSwiftDependencies.begin(),
@@ -830,8 +969,7 @@ ModuleDependencyScanner::resolveSwiftModuleDependencies(
   return;
 }
 
-void
-ModuleDependencyScanner::resolveAllClangModuleDependencies(
+void ModuleDependencyScanner::resolveAllClangModuleDependencies(
     ArrayRef<ModuleDependencyID> swiftModuleDependents,
     ModuleDependenciesCache &cache,
     ModuleDependencyIDSetVector &allDiscoveredClangModules) {
@@ -839,13 +977,23 @@ ModuleDependencyScanner::resolveAllClangModuleDependencies(
   // Clang modules (since no Swift module for them was found).
   llvm::StringSet<> unresolvedImportIdentifiers;
   llvm::StringSet<> unresolvedOptionalImportIdentifiers;
-  std::unordered_map<ModuleDependencyID, std::vector<ScannerImportStatementInfo>> unresolvedImportsMap;
-  std::unordered_map<ModuleDependencyID, std::vector<ScannerImportStatementInfo>> unresolvedOptionalImportsMap;
+  std::unordered_map<ModuleDependencyID,
+                     std::vector<ScannerImportStatementInfo>>
+      unresolvedImportsMap;
+  std::unordered_map<ModuleDependencyID,
+                     std::vector<ScannerImportStatementInfo>>
+      unresolvedOptionalImportsMap;
 
   for (const auto &moduleID : swiftModuleDependents) {
     auto moduleDependencyInfo = cache.findKnownDependency(moduleID);
-    auto unresolvedImports = &unresolvedImportsMap.emplace(moduleID, std::vector<ScannerImportStatementInfo>()).first->second;
-    auto unresolvedOptionalImports = &unresolvedOptionalImportsMap.emplace(moduleID, std::vector<ScannerImportStatementInfo>()).first->second;
+    auto unresolvedImports =
+        &unresolvedImportsMap
+             .emplace(moduleID, std::vector<ScannerImportStatementInfo>())
+             .first->second;
+    auto unresolvedOptionalImports =
+        &unresolvedOptionalImportsMap
+             .emplace(moduleID, std::vector<ScannerImportStatementInfo>())
+             .first->second;
 
     // If we have already resolved Clang dependencies for this module,
     // then we have the entire dependency sub-graph already computed for
@@ -861,7 +1009,7 @@ ModuleDependencyScanner::resolveAllClangModuleDependencies(
            ++currentModuleIdx) {
         auto moduleID = reachableClangModules[currentModuleIdx];
         auto dependencies =
-          cache.findKnownDependency(moduleID).getImportedClangDependencies();
+            cache.findKnownDependency(moduleID).getImportedClangDependencies();
         reachableClangModules.insert(dependencies.begin(), dependencies.end());
       }
       allDiscoveredClangModules.insert(reachableClangModules.begin(),
@@ -869,66 +1017,66 @@ ModuleDependencyScanner::resolveAllClangModuleDependencies(
       continue;
     } else {
       // We need to query the Clang dependency scanner for this module's
-      // unresolved imports
+      // non-Swift imports
       llvm::StringSet<> resolvedImportIdentifiers;
-      for (const auto &resolvedDep : moduleDependencyInfo.getImportedSwiftDependencies())
+      for (const auto &resolvedDep :
+           moduleDependencyInfo.getImportedSwiftDependencies())
         resolvedImportIdentifiers.insert(resolvedDep.ModuleName);
 
+      // When querying a *clang* module 'CxxStdlib' we must
+      // instead expect a module called 'std'...
+      auto addCanonicalClangModuleImport =
+          [this](const ScannerImportStatementInfo &importInfo,
+                 std::vector<ScannerImportStatementInfo> &unresolvedImports,
+                 llvm::StringSet<> &unresolvedImportIdentifiers) {
+            if (importInfo.importIdentifier ==
+                ScanASTContext.Id_CxxStdlib.str()) {
+              auto canonicalImportInfo = ScannerImportStatementInfo(
+                  "std", importInfo.isExported, importInfo.accessLevel,
+                  importInfo.importLocations);
+              unresolvedImports.push_back(canonicalImportInfo);
+              unresolvedImportIdentifiers.insert(
+                  canonicalImportInfo.importIdentifier);
+            } else {
+              unresolvedImports.push_back(importInfo);
+              unresolvedImportIdentifiers.insert(importInfo.importIdentifier);
+            }
+          };
+
       for (const auto &depImport : moduleDependencyInfo.getModuleImports())
-        if (!resolvedImportIdentifiers.contains(depImport.importIdentifier)) {
-          unresolvedImports->push_back(depImport);
-          unresolvedImportIdentifiers.insert(depImport.importIdentifier);
-        }
-      for (const auto &depImport : moduleDependencyInfo.getOptionalModuleImports())
-        if (!resolvedImportIdentifiers.contains(depImport.importIdentifier)) {
-          unresolvedOptionalImports->push_back(depImport);
-          unresolvedOptionalImportIdentifiers.insert(depImport.importIdentifier);
-        }
+        if (!resolvedImportIdentifiers.contains(depImport.importIdentifier))
+          addCanonicalClangModuleImport(depImport, *unresolvedImports,
+                                        unresolvedImportIdentifiers);
+      for (const auto &depImport :
+           moduleDependencyInfo.getOptionalModuleImports())
+        if (!resolvedImportIdentifiers.contains(depImport.importIdentifier))
+          addCanonicalClangModuleImport(depImport, *unresolvedOptionalImports,
+                                        unresolvedOptionalImportIdentifiers);
     }
   }
 
-  // Prepare the module lookup result collection
-  llvm::StringMap<std::optional<ModuleDependencyVector>> moduleLookupResult;
-  for (const auto &unresolvedIdentifier : unresolvedImportIdentifiers)
-    moduleLookupResult.insert(
-        std::make_pair(unresolvedIdentifier.getKey(), std::nullopt));
-
-  // We need a copy of the shared already-seen module set, which will be shared amongst
-  // all the workers. In `recordDependencies`, each worker will contribute its
-  // results back to the shared set for future lookups.
-  const llvm::DenseSet<clang::tooling::dependencies::ModuleID> seenClangModules =
-      cache.getAlreadySeenClangModules();
-  std::mutex cacheAccessLock;
-  auto scanForClangModuleDependency =
-      [this, &cache, &moduleLookupResult,
-       &cacheAccessLock, &seenClangModules](Identifier moduleIdentifier) {
-        auto moduleName = moduleIdentifier.str();
-        {
-          std::lock_guard<std::mutex> guard(cacheAccessLock);
-          if (cache.hasDependency(moduleName, ModuleDependencyKind::Clang))
-            return;
-        }
-
-        auto moduleDependencies = withDependencyScanningWorker(
-            [&cache, &seenClangModules,
-             moduleIdentifier](ModuleDependencyScanningWorker *ScanningWorker) {
-              return ScanningWorker->scanFilesystemForClangModuleDependency(
-                  moduleIdentifier, cache.getModuleOutputPath(),
-                  cache.getSDKModuleOutputPath(), seenClangModules,
-                  cache.getScanService().getPrefixMapper());
-            });
-
-        // Update the `moduleLookupResult` and cache all discovered dependencies
-        // so that subsequent queries do not have to call into the scanner
-        // if looking for a module that was discovered as a transitive dependency
-        // in this scan.
-        {
-          std::lock_guard<std::mutex> guard(cacheAccessLock);
-          moduleLookupResult.insert_or_assign(moduleName, moduleDependencies);
-          if (!moduleDependencies.empty())
-            cache.recordDependencies(moduleDependencies);
-        }
-      };
+  // Module lookup result collection
+  llvm::StringMap<
+      std::optional<clang::tooling::dependencies::TranslationUnitDeps>>
+      moduleLookupResult;
+  auto seenClangModules = cache.getAlreadySeenClangModules();
+  std::mutex resultAccessLock;
+  auto scanForClangModuleDependency = [this, &moduleLookupResult,
+                                       &resultAccessLock, &seenClangModules](
+                                          Identifier moduleIdentifier) {
+    auto scanResult = withDependencyScanningWorker(
+        [&](ModuleDependencyScanningWorker *ScanningWorker) {
+          auto lookupModuleOutput = [this](const auto &cd, auto mok) -> auto {
+            return clangModuleOutputPathLookup(cd, mok);
+          };
+          return ScanningWorker->scanFilesystemForClangModuleDependency(
+              moduleIdentifier, lookupModuleOutput, seenClangModules);
+        });
+    {
+      std::lock_guard<std::mutex> guard(resultAccessLock);
+      moduleLookupResult.insert_or_assign(moduleIdentifier.str(), scanResult);
+    }
+  };
 
   // Enque asynchronous lookup tasks
   for (const auto &unresolvedIdentifier : unresolvedImportIdentifiers)
@@ -946,29 +1094,38 @@ ModuleDependencyScanner::resolveAllClangModuleDependencies(
     std::vector<ScannerImportStatementInfo> failedToResolveImports;
     ModuleDependencyIDSetVector importedClangDependencies;
     auto recordResolvedClangModuleImport =
-        [&moduleLookupResult, &importedClangDependencies,
-         &allDiscoveredClangModules, moduleID,
-         &failedToResolveImports](const ScannerImportStatementInfo &moduleImport,
-                                  bool optionalImport) {
-          auto lookupResult = moduleLookupResult[moduleImport.importIdentifier];
-          // The imported module was found in the cache
-          if (lookupResult == std::nullopt) {
+        [this, &moduleLookupResult, &importedClangDependencies, &cache,
+         &allDiscoveredClangModules, moduleID, &failedToResolveImports](
+            const ScannerImportStatementInfo &moduleImport,
+            bool optionalImport) {
+          ASSERT(moduleLookupResult.contains(moduleImport.importIdentifier));
+          const auto &lookupResult =
+              moduleLookupResult.at(moduleImport.importIdentifier);
+          if (lookupResult.has_value()) {
+            cache.recordClangDependencies(
+                lookupResult->ModuleGraph, ScanASTContext.Diags,
+                [this](auto &clangDep) {
+                  return bridgeClangModuleDependency(clangDep);
+                });
+
+            // Add the full transitive dependency set
+            for (const auto &dep : lookupResult->ModuleGraph)
+              allDiscoveredClangModules.insert(
+                  {dep.ID.ModuleName, ModuleDependencyKind::Clang});
+
             importedClangDependencies.insert(
                 {moduleImport.importIdentifier, ModuleDependencyKind::Clang});
-          } else {
-            // Cache discovered module dependencies.
-            if (!lookupResult.value().empty()) {
-              importedClangDependencies.insert(
-                  {moduleImport.importIdentifier, ModuleDependencyKind::Clang});
-              // Add the full transitive dependency set
-              for (const auto &dep : lookupResult.value())
-                allDiscoveredClangModules.insert(dep.first);
-            } else if (!optionalImport) {
-              // Otherwise, we failed to resolve this dependency. We will try
-              // again using the cache after all other imports have been resolved.
-              // If that fails too, a scanning failure will be diagnosed.
-              failedToResolveImports.push_back(moduleImport);
-            }
+
+            // Add visible Clang modules for this query to the depending
+            // Swift module
+            cache.addVisibleClangModules(moduleID,
+                                         lookupResult->VisibleModules);
+          } else if (!optionalImport) {
+            // Otherwise, we failed to resolve this dependency. We will try
+            // again using the cache after all other imports have been
+            // resolved. If that fails too, a scanning failure will be
+            // diagnosed.
+            failedToResolveImports.push_back(moduleImport);
           }
         };
 
@@ -977,11 +1134,11 @@ ModuleDependencyScanner::resolveAllClangModuleDependencies(
     for (const auto &unresolvedImport : unresolvedOptionalImportsMap[moduleID])
       recordResolvedClangModuleImport(unresolvedImport, true);
 
-    // It is possible that a specific import resolution failed because we are attempting to
-    // resolve a module which can only be brought in via a modulemap of a
-    // different Clang module dependency which is not otherwise on the current
-    // search paths. For example, suppose we are scanning a `.swiftinterface` for
-    // module `Foo`, which contains:
+    // It is possible that a specific import resolution failed because we are
+    // attempting to resolve a module which can only be brought in via a
+    // modulemap of a different Clang module dependency which is not otherwise
+    // on the current search paths. For example, suppose we are scanning a
+    // `.swiftinterface` for module `Foo`, which contains:
     // -----
     // @_exported import Foo
     // import Bar
@@ -993,27 +1150,33 @@ ModuleDependencyScanner::resolveAllClangModuleDependencies(
     // `<some_framework_search_path>/Foo.framework/Modules/module.modulemap`.
     // Which means that lookup of `Bar` alone from Swift will not be able to
     // locate the module in it. However, the lookup of Foo will itself bring in
-    // the auxiliary module becuase the Clang scanner instance scanning for clang
-    // module Foo will be able to find it in the corresponding framework module's
-    // modulemap and register it as a dependency which means it will be registered
-    // with the scanner's cache in the step above. To handle such cases, we
-    // first add all successfully-resolved modules and (for Clang modules) their
-    // transitive dependencies to the cache, and then attempt to re-query imports
-    // for which resolution originally failed from the cache. If this fails, then
-    // the scanner genuinely failed to resolve this dependency.
+    // the auxiliary module becuase the Clang scanner instance scanning for
+    // clang module Foo will be able to find it in the corresponding framework
+    // module's modulemap and register it as a dependency which means it will be
+    // registered with the scanner's cache in the step above. To handle such
+    // cases, we first add all successfully-resolved modules and (for Clang
+    // modules) their transitive dependencies to the cache, and then attempt to
+    // re-query imports for which resolution originally failed from the cache.
+    // If this fails, then the scanner genuinely failed to resolve this
+    // dependency.
     for (const auto &unresolvedImport : failedToResolveImports) {
-      auto unresolvedModuleID = ModuleDependencyID{unresolvedImport.importIdentifier,
-                                                   ModuleDependencyKind::Clang};
-      auto optionalCachedModuleInfo =
-        cache.findDependency(unresolvedModuleID);
+      auto unresolvedModuleID = ModuleDependencyID{
+          unresolvedImport.importIdentifier, ModuleDependencyKind::Clang};
+      auto optionalCachedModuleInfo = cache.findDependency(unresolvedModuleID);
       if (optionalCachedModuleInfo.has_value())
         importedClangDependencies.insert(unresolvedModuleID);
-      else
-        diagnoseScannerFailure(unresolvedImport, Diagnostics, cache, moduleID);
+      else {
+        // Failed to resolve module dependency.
+        IssueReporter.diagnoseModuleNotFoundFailure(
+            unresolvedImport, cache, moduleID,
+            attemptToFindResolvingSerializedSearchPath(unresolvedImport,
+                                                       cache));
+      }
     }
 
     if (!importedClangDependencies.empty())
-      cache.setImportedClangDependencies(moduleID, importedClangDependencies.takeVector());
+      cache.setImportedClangDependencies(
+          moduleID, importedClangDependencies.takeVector());
   }
 
   return;
@@ -1040,8 +1203,7 @@ void ModuleDependencyScanner::resolveHeaderDependencies(
   }
 }
 
-void
-ModuleDependencyScanner::resolveSwiftOverlayDependencies(
+void ModuleDependencyScanner::resolveSwiftOverlayDependencies(
     ArrayRef<ModuleDependencyID> allSwiftModules,
     ModuleDependenciesCache &cache,
     ModuleDependencyIDSetVector &allDiscoveredDependencies) {
@@ -1049,11 +1211,13 @@ ModuleDependencyScanner::resolveSwiftOverlayDependencies(
   for (const auto &moduleID : allSwiftModules) {
     auto moduleDependencyInfo = cache.findKnownDependency(moduleID);
     if (!moduleDependencyInfo.getSwiftOverlayDependencies().empty()) {
-      allDiscoveredDependencies.insert(moduleDependencyInfo.getSwiftOverlayDependencies().begin(),
-                                       moduleDependencyInfo.getSwiftOverlayDependencies().end());
+      allDiscoveredDependencies.insert(
+          moduleDependencyInfo.getSwiftOverlayDependencies().begin(),
+          moduleDependencyInfo.getSwiftOverlayDependencies().end());
     } else {
       ModuleDependencyIDSetVector swiftOverlayDependencies;
-      resolveSwiftOverlayDependenciesForModule(moduleID, cache, swiftOverlayDependencies);
+      resolveSwiftOverlayDependenciesForModule(moduleID, cache,
+                                               swiftOverlayDependencies);
       discoveredSwiftOverlays.insert(swiftOverlayDependencies.begin(),
                                      swiftOverlayDependencies.end());
     }
@@ -1063,7 +1227,7 @@ ModuleDependencyScanner::resolveSwiftOverlayDependencies(
   // in case it itself has unresolved module dependencies.
   for (const auto &overlayDepID : discoveredSwiftOverlays) {
     ModuleDependencyIDSetVector allNewModules =
-      resolveImportedModuleDependencies(overlayDepID, cache);
+       resolveImportedModuleDependencies(overlayDepID, cache);
     allDiscoveredDependencies.insert(allNewModules.begin(),
                                      allNewModules.end());
   }
@@ -1081,17 +1245,14 @@ void ModuleDependencyScanner::resolveSwiftImportsForModule(
     return;
 
   auto moduleDependencyInfo = cache.findKnownDependency(moduleID);
-  llvm::StringMap<std::optional<ModuleDependencyVector>> moduleLookupResult;
-  for (const auto &dependsOn : moduleDependencyInfo.getModuleImports())
-    moduleLookupResult.insert(
-        std::make_pair(dependsOn.importIdentifier, std::nullopt));
+  llvm::StringMap<SwiftModuleScannerQueryResult> moduleLookupResult;
   std::mutex lookupResultLock;
 
   // A scanning task to query a module by-name. If the module already exists
   // in the cache, do nothing and return.
   auto scanForSwiftModuleDependency =
-      [this, &cache, &lookupResultLock, &moduleLookupResult](Identifier moduleIdentifier,
-                                                             bool isTestable) {
+      [this, &cache, &lookupResultLock,
+       &moduleLookupResult](Identifier moduleIdentifier, bool isTestable) {
         auto moduleName = moduleIdentifier.str().str();
         {
           std::lock_guard<std::mutex> guard(lookupResultLock);
@@ -1100,12 +1261,10 @@ void ModuleDependencyScanner::resolveSwiftImportsForModule(
         }
 
         auto moduleDependencies = withDependencyScanningWorker(
-            [&cache, moduleIdentifier,
+            [moduleIdentifier,
              isTestable](ModuleDependencyScanningWorker *ScanningWorker) {
               return ScanningWorker->scanFilesystemForSwiftModuleDependency(
-                  moduleIdentifier, cache.getModuleOutputPath(),
-                  cache.getSDKModuleOutputPath(),
-                  cache.getScanService().getPrefixMapper(), isTestable);
+                  moduleIdentifier, isTestable);
             });
 
         {
@@ -1137,25 +1296,31 @@ void ModuleDependencyScanner::resolveSwiftImportsForModule(
   ScanningThreadPool.wait();
 
   auto recordResolvedModuleImport =
-      [&cache, &moduleLookupResult, &importedSwiftDependencies,
+      [this, &cache, &moduleLookupResult, &importedSwiftDependencies,
        moduleID](const ScannerImportStatementInfo &moduleImport) {
         if (moduleID.ModuleName == moduleImport.importIdentifier)
           return;
         auto lookupResult = moduleLookupResult[moduleImport.importIdentifier];
-        // The imported module was found in the cache
-        if (lookupResult == std::nullopt) {
-          auto cachedInfo = cache.findSwiftDependency(moduleImport.importIdentifier);
-          if (cachedInfo.has_value())
-            importedSwiftDependencies.insert(
+
+        // Query found module
+        if (lookupResult.foundDependencyInfo) {
+          cache.recordDependency(moduleImport.importIdentifier,
+                                 *(lookupResult.foundDependencyInfo));
+          importedSwiftDependencies.insert(
+              {moduleImport.importIdentifier,
+               lookupResult.foundDependencyInfo->getKind()});
+          IssueReporter.warnOnIncompatibleCandidates(
+              moduleImport.importIdentifier,
+              lookupResult.incompatibleCandidates);
+          // Module was resolved from a cache
+        } else if (auto cachedInfo = cache.findSwiftDependency(
+                       moduleImport.importIdentifier))
+          importedSwiftDependencies.insert(
               {moduleImport.importIdentifier, cachedInfo.value()->getKind()});
-        } else {
-          // Cache discovered module dependencies.
-          if (!lookupResult.value().empty()) {
-            cache.recordDependencies(lookupResult.value());
-            importedSwiftDependencies.insert({moduleImport.importIdentifier,
-                                              lookupResult.value()[0].first.Kind});
-          }
-        }
+        else
+          IssueReporter.diagnoseFailureOnOnlyIncompatibleCandidates(
+              moduleImport, lookupResult.incompatibleCandidates, cache,
+              std::nullopt);
       };
 
   for (const auto &importInfo : moduleDependencyInfo.getModuleImports())
@@ -1171,8 +1336,8 @@ void ModuleDependencyScanner::resolveSwiftImportsForModule(
 void ModuleDependencyScanner::resolveHeaderDependenciesForModule(
     const ModuleDependencyID &moduleID, ModuleDependenciesCache &cache,
     ModuleDependencyIDSetVector &headerClangModuleDependencies) {
-  PrettyStackTraceStringAction trace("Resolving header dependencies of Swift module",
-                                     moduleID.ModuleName);
+  PrettyStackTraceStringAction trace(
+      "Resolving header dependencies of Swift module", moduleID.ModuleName);
   std::vector<std::string> allClangModules;
   llvm::StringSet<> alreadyKnownModules;
   auto moduleDependencyInfo = cache.findKnownDependency(moduleID);
@@ -1187,7 +1352,6 @@ void ModuleDependencyScanner::resolveHeaderDependenciesForModule(
   if (!isTextualModuleWithABridgingHeader && !isBinaryModuleWithHeaderInput)
     return;
 
-
   std::optional<std::string> headerPath;
   std::unique_ptr<llvm::MemoryBuffer> sourceBuffer;
   std::optional<llvm::MemoryBufferRef> sourceBufferRef;
@@ -1205,12 +1369,8 @@ void ModuleDependencyScanner::resolveHeaderDependenciesForModule(
     if (!moduleBuf)
       return nullptr;
 
-    auto content = extractEmbeddedBridgingHeaderContent(std::move(*moduleBuf),
-                                                        ScanASTContext);
-    if (content.empty())
-      return nullptr;
-
-    return llvm::MemoryBuffer::getMemBufferCopy(content, header);
+    return extractEmbeddedBridgingHeaderContent(std::move(*moduleBuf), header,
+                                                ScanASTContext);
   };
 
   if (isBinaryModuleWithHeaderInput) {
@@ -1225,21 +1385,46 @@ void ModuleDependencyScanner::resolveHeaderDependenciesForModule(
 
   withDependencyScanningWorker(
       [&](ModuleDependencyScanningWorker *ScanningWorker) {
-        auto clangImporter = static_cast<ClangImporter *>(
-            ScanningWorker->clangScannerModuleLoader.get());
-
         std::vector<std::string> headerFileInputs;
         std::optional<std::string> includeTreeID;
         std::vector<std::string> bridgingHeaderCommandLine;
-        auto headerScan = clangImporter->getHeaderDependencies(
-            moduleID, headerPath, sourceBufferRef,
-            ScanningWorker->clangScanningTool, cache,
-            headerClangModuleDependencies, headerFileInputs,
-            bridgingHeaderCommandLine, includeTreeID);
-        if (!headerScan) {
+        std::vector<std::string> visibleClangModules;
+        auto lookupModuleOutput = [this](const auto &cd, auto mok) -> auto {
+          return clangModuleOutputPathLookup(cd, mok);
+        };
+        auto headerScanResult =
+            ScanningWorker->scanHeaderDependenciesOfSwiftModule(
+                moduleID, headerPath, sourceBufferRef, lookupModuleOutput,
+                cache.getAlreadySeenClangModules());
+
+        if (headerScanResult) {
+          // Record module dependencies for each new module we found.
+          cache.recordClangDependencies(
+              headerScanResult->ModuleGraph, ScanASTContext.Diags,
+              [this](auto &clangDep) {
+                return bridgeClangModuleDependency(clangDep);
+              });
+          llvm::copy(headerScanResult->FileDeps,
+                     std::back_inserter(headerFileInputs));
+          auto bridgedDependencyIDs = llvm::map_range(
+              headerScanResult->ClangModuleDeps, [](auto &input) {
+                return ModuleDependencyID{input.ModuleName,
+                                          ModuleDependencyKind::Clang};
+              });
+          headerClangModuleDependencies.insert(bridgedDependencyIDs.begin(),
+                                               bridgedDependencyIDs.end());
+
+          auto targetModuleInfo = cache.findKnownDependency(moduleID);
+          if (targetModuleInfo.isTextualSwiftModule()) {
+            if (auto TreeID = headerScanResult->IncludeTreeID)
+              includeTreeID = TreeID;
+            ClangImporter::getBridgingHeaderOptions(
+                ScanASTContext, *headerScanResult, bridgingHeaderCommandLine);
+          }
+
           // Record direct header Clang dependencies
-          cache.setHeaderClangDependencies(
-              moduleID, headerClangModuleDependencies.getArrayRef());
+          moduleDependencyInfo.setHeaderClangDependencies(
+              headerClangModuleDependencies.getArrayRef());
           // Record include Tree ID
           if (includeTreeID)
             moduleDependencyInfo.addBridgingHeaderIncludeTree(*includeTreeID);
@@ -1248,6 +1433,9 @@ void ModuleDependencyScanner::resolveHeaderDependenciesForModule(
             moduleDependencyInfo.updateBridgingHeaderCommandLine(
                 bridgingHeaderCommandLine);
           moduleDependencyInfo.setHeaderSourceFiles(headerFileInputs);
+          // Update the set of visible Clang modules
+          moduleDependencyInfo.addVisibleClangModules(
+              headerScanResult->VisibleModules);
           // Update the dependency in the cache
           cache.updateDependency(moduleID, moduleDependencyInfo);
         } else {
@@ -1255,82 +1443,118 @@ void ModuleDependencyScanner::resolveHeaderDependenciesForModule(
         }
         return true;
       });
-  cache.setHeaderClangDependencies(moduleID,
-                                   headerClangModuleDependencies.getArrayRef());
 }
 
 void ModuleDependencyScanner::resolveSwiftOverlayDependenciesForModule(
-    const ModuleDependencyID &moduleID,
-    ModuleDependenciesCache &cache,
+    const ModuleDependencyID &moduleID, ModuleDependenciesCache &cache,
     ModuleDependencyIDSetVector &swiftOverlayDependencies) {
-  PrettyStackTraceStringAction trace("Resolving Swift Overlay dependencies of module",
-                                     moduleID.ModuleName);
-  std::vector<std::string> allClangDependencies;
-  llvm::StringSet<> knownModules;
-
-  // Find all of the discovered Clang modules that this module depends on.
-  for (const auto &dep : cache.getClangDependencies(moduleID))
-    findAllImportedClangModules(dep.ModuleName, cache, allClangDependencies,
-                                knownModules);
+  PrettyStackTraceStringAction trace(
+      "Resolving Swift Overlay dependencies of module", moduleID.ModuleName);
+  auto visibleClangDependencies = cache.getVisibleClangModules(moduleID);
 
-  llvm::StringMap<std::optional<ModuleDependencyVector>>
-      swiftOverlayLookupResult;
-  for (const auto &clangDep : allClangDependencies)
-    swiftOverlayLookupResult.insert(std::make_pair(clangDep, std::nullopt));
+  llvm::StringMap<SwiftModuleScannerQueryResult> swiftOverlayLookupResult;
+  std::mutex lookupResultLock;
 
   // A scanning task to query a Swift module by-name. If the module already
   // exists in the cache, do nothing and return.
-  auto scanForSwiftDependency = [this, &cache, &swiftOverlayLookupResult](
+  auto scanForSwiftDependency = [this, &moduleID, &cache, &lookupResultLock,
+                                 &swiftOverlayLookupResult](
                                     Identifier moduleIdentifier) {
     auto moduleName = moduleIdentifier.str();
-    if (cache.hasDependency(moduleName, ModuleDependencyKind::SwiftInterface) ||
-        cache.hasDependency(moduleName, ModuleDependencyKind::SwiftBinary) ||
-        cache.hasDependency(moduleName, ModuleDependencyKind::SwiftPlaceholder))
+    {
+      std::lock_guard<std::mutex> guard(lookupResultLock);
+      if (cache.hasDependency(moduleName, ModuleDependencyKind::SwiftInterface) ||
+          cache.hasDependency(moduleName, ModuleDependencyKind::SwiftBinary))
+        return;
+    }
+
+    // Avoid Swift overlay lookup for the underlying clang module of a known
+    // Swift module. i.e. When computing set of Swift Overlay dependencies
+    // for module 'A', which depends on a Clang module 'A', ensure we don't
+    // lookup Swift module 'A' itself here.
+    if (moduleName == moduleID.ModuleName)
       return;
 
     auto moduleDependencies = withDependencyScanningWorker(
-        [&cache,
-         moduleIdentifier](ModuleDependencyScanningWorker *ScanningWorker) {
+        [moduleIdentifier](ModuleDependencyScanningWorker *ScanningWorker) {
           return ScanningWorker->scanFilesystemForSwiftModuleDependency(
-              moduleIdentifier, cache.getModuleOutputPath(),
-              cache.getSDKModuleOutputPath(),
-              cache.getScanService().getPrefixMapper());
+              moduleIdentifier, /* isTestableImport */ false);
         });
-    swiftOverlayLookupResult.insert_or_assign(moduleName, moduleDependencies);
+                                      
+    {
+      std::lock_guard<std::mutex> guard(lookupResultLock);
+      swiftOverlayLookupResult.insert_or_assign(moduleName, moduleDependencies);
+    }
   };
 
   // Enque asynchronous lookup tasks
-  for (const auto &clangDep : allClangDependencies)
-    ScanningThreadPool.async(scanForSwiftDependency, getModuleImportIdentifier(clangDep));
+  for (const auto &clangDep : visibleClangDependencies)
+    ScanningThreadPool.async(scanForSwiftDependency,
+                             getModuleImportIdentifier(clangDep.getKey().str()));
   ScanningThreadPool.wait();
 
   // Aggregate both previously-cached and freshly-scanned module results
-  auto recordResult = [&cache, &swiftOverlayLookupResult,
+  auto recordResult = [this, &cache, &swiftOverlayLookupResult,
                        &swiftOverlayDependencies,
                        moduleID](const std::string &moduleName) {
     auto lookupResult = swiftOverlayLookupResult[moduleName];
     if (moduleName != moduleID.ModuleName) {
-      if (lookupResult == std::nullopt) {
-        auto cachedInfo = cache.findSwiftDependency(moduleName);
-        if (cachedInfo.has_value())
-          swiftOverlayDependencies.insert(
+
+      // Query found module
+      if (lookupResult.foundDependencyInfo) {
+        cache.recordDependency(moduleName, *(lookupResult.foundDependencyInfo));
+        swiftOverlayDependencies.insert(
+            {moduleName, lookupResult.foundDependencyInfo->getKind()});
+        IssueReporter.warnOnIncompatibleCandidates(
+            moduleName, lookupResult.incompatibleCandidates);
+        // Module was resolved from a cache
+      } else if (auto cachedInfo = cache.findSwiftDependency(moduleName))
+        swiftOverlayDependencies.insert(
             {moduleName, cachedInfo.value()->getKind()});
-      } else {
-        // Cache discovered module dependencies.
-        cache.recordDependencies(lookupResult.value());
-        if (!lookupResult.value().empty())
-          swiftOverlayDependencies.insert({moduleName, lookupResult.value()[0].first.Kind});
-      }
+      else
+        IssueReporter.diagnoseFailureOnOnlyIncompatibleCandidates(
+            ScannerImportStatementInfo(moduleName),
+            lookupResult.incompatibleCandidates, cache, std::nullopt);
     }
   };
-  for (const auto &clangDep : allClangDependencies)
-    recordResult(clangDep);
+  for (const auto &clangDep : visibleClangDependencies)
+    recordResult(clangDep.getKey().str());
 
   // C++ Interop requires additional handling
-  if (ScanCompilerInvocation.getLangOptions().EnableCXXInterop) {
-    for (const auto &clangDepName : allClangDependencies) {
-      // If this Clang module is a part of the C++ stdlib, and we haven't loaded
-      // the overlay for it so far, it is a split libc++ module (e.g.
+  bool lookupCxxStdLibOverlay =
+      ScanCompilerInvocation.getLangOptions().EnableCXXInterop;
+  if (lookupCxxStdLibOverlay &&
+      moduleID.Kind == ModuleDependencyKind::SwiftInterface) {
+    const auto &moduleInfo = cache.findKnownDependency(moduleID);
+    const auto commandLine = moduleInfo.getCommandline();
+    // If the textual interface was built without C++ interop, do not query
+    // the C++ Standard Library Swift overlay for its compilation.
+    if (llvm::find(commandLine, "-formal-cxx-interoperability-mode=off") !=
+        commandLine.end())
+      lookupCxxStdLibOverlay = false;
+  } else if (lookupCxxStdLibOverlay &&
+             moduleID.Kind == ModuleDependencyKind::SwiftBinary) {
+    const auto &moduleDetails =
+        cache.findKnownDependency(moduleID).getAsSwiftBinaryModule();
+    // If the binary module was built without C++ interop, do not query
+    // the C++ Standard Library Swift overlay.
+    if (!moduleDetails->isBuiltWithCxxInterop)
+      lookupCxxStdLibOverlay = false;
+  }
+
+  // FIXME: We always declare the 'Darwin' module as formally having been built
+  // without C++Interop, for compatibility with prior versions. Once we are certain
+  // that we are only building against modules built with support of
+  // '-formal-cxx-interoperability-mode', this hard-coded check should be removed.
+  if (lookupCxxStdLibOverlay && moduleID.ModuleName == "Darwin")
+    lookupCxxStdLibOverlay = false;
+
+  if (lookupCxxStdLibOverlay) {
+    for (const auto &clangDepNameEntry : visibleClangDependencies) {
+      auto clangDepName = clangDepNameEntry.getKey().str();
+
+      // If this Clang module is a part of the C++ stdlib, and we haven't
+      // loaded the overlay for it so far, it is a split libc++ module (e.g.
       // std_vector). Load the CxxStdlib overlay explicitly.
       const auto &clangDepInfo =
           cache.findDependency(clangDepName, ModuleDependencyKind::Clang)
@@ -1341,22 +1565,22 @@ void ModuleDependencyScanner::resolveSwiftOverlayDependenciesForModule(
               {clangDepName, ModuleDependencyKind::SwiftInterface}) &&
           !swiftOverlayDependencies.contains(
               {clangDepName, ModuleDependencyKind::SwiftBinary})) {
-        ScanningThreadPool.async(
-            scanForSwiftDependency,
+        scanForSwiftDependency(
             getModuleImportIdentifier(ScanASTContext.Id_CxxStdlib.str()));
-        ScanningThreadPool.wait();
         recordResult(ScanASTContext.Id_CxxStdlib.str().str());
+        break;
       }
     }
   }
 
-  // Resolve the dependency info with Swift overlay dependency module information.
-  cache.setSwiftOverlayDependencies(moduleID, swiftOverlayDependencies.getArrayRef());
+  // Resolve the dependency info with Swift overlay dependency module
+  // information.
+  cache.setSwiftOverlayDependencies(moduleID,
+                                    swiftOverlayDependencies.getArrayRef());
 }
 
 void ModuleDependencyScanner::resolveCrossImportOverlayDependencies(
-    StringRef mainModuleName,
-    ModuleDependenciesCache &cache,
+    StringRef mainModuleName, ModuleDependenciesCache &cache,
     llvm::function_ref<void(ModuleDependencyID)> action) {
   // Modules explicitly imported. Only these can be secondary module.
   llvm::SetVector<Identifier> newOverlays;
@@ -1375,13 +1599,15 @@ void ModuleDependencyScanner::resolveCrossImportOverlayDependencies(
                                         ModuleDependencyKind::SwiftSource};
   auto actualMainID = ModuleDependencyID{mainModuleName.str(),
                                          ModuleDependencyKind::SwiftSource};
-  auto dummyMainDependencies =
-     ModuleDependencyInfo::forSwiftSourceModule();
-  std::for_each(newOverlays.begin(), newOverlays.end(),
-                [&](Identifier modName) {
-                  dummyMainDependencies.addModuleImport(modName.str(),
-                                                        /* isExported */ false);
-                });
+  auto dummyMainDependencies = ModuleDependencyInfo::forSwiftSourceModule();
+  std::for_each(
+      newOverlays.begin(), newOverlays.end(), [&](Identifier modName) {
+        dummyMainDependencies.addModuleImport(
+            modName.str(),
+            /* isExported */ false,
+            // TODO: What is the right access level for a cross-import overlay?
+            AccessLevel::Public);
+      });
 
   // Record the dummy main module's direct dependencies. The dummy main module
   // only directly depend on these newly discovered overlay modules.
@@ -1394,19 +1620,19 @@ void ModuleDependencyScanner::resolveCrossImportOverlayDependencies(
     resolveImportedModuleDependencies(dummyMainID, cache);
 
   // Update main module's dependencies to include these new overlays.
-  auto newOverlayDeps = cache.getAllDependencies(dummyMainID);
-  cache.setCrossImportOverlayDependencies(actualMainID, newOverlayDeps.getArrayRef());
+  cache.setCrossImportOverlayDependencies(actualMainID,
+                                          cache.getAllDependencies(dummyMainID));
 
-  // Update the command-line on the main module to
-  // disable implicit cross-import overlay search.
+  // Update the command-line on the main module to disable implicit
+  // cross-import overlay search.
   auto mainDep = cache.findKnownDependency(actualMainID);
-  auto cmdCopy = mainDep.getCommandline();
+  std::vector<std::string> cmdCopy = mainDep.getCommandline();
   cmdCopy.push_back("-disable-cross-import-overlay-search");
   for (auto &entry : overlayFiles) {
     mainDep.addAuxiliaryFile(entry.second);
     cmdCopy.push_back("-swift-module-cross-import");
     cmdCopy.push_back(entry.first);
-    auto overlayPath = cache.getScanService().remapPath(entry.second);
+    auto overlayPath = remapPath(entry.second);
     cmdCopy.push_back(overlayPath);
   }
   mainDep.updateCommandLine(cmdCopy);
@@ -1424,95 +1650,166 @@ llvm::Error ModuleDependencyScanner::performBridgingHeaderChaining(
   if (rootModuleID.Kind != ModuleDependencyKind::SwiftSource)
     return llvm::Error::success();
 
-  bool hasBridgingHeader = false;
-  llvm::vfs::OnDiskOutputBackend outputBackend;
+  llvm::SmallString<256> chainedHeaderBuffer;
+  llvm::raw_svector_ostream outOS(chainedHeaderBuffer);
+
+  // If prefix mapping is used, don't try to import header since that will add
+  // a path-relative component into dependency scanning and defeat the purpose
+  // of prefix mapping. Additionally, if everything is prefix mapped, the
+  // embedded header path is also prefix mapped, thus it can't be found anyway.
+  bool useImportHeader = !hasPathMapping();
+  auto FS = ScanASTContext.SourceMgr.getFileSystem();
+
+  auto chainBridgingHeader = [&](StringRef moduleName, StringRef headerPath,
+                                 StringRef binaryModulePath) -> llvm::Error {
+    if (useImportHeader) {
+      if (auto buffer = FS->getBufferForFile(headerPath)) {
+        outOS << "#include \"" << headerPath << "\"\n";
+        return llvm::Error::success();
+      }
+    }
 
-  SmallString<256> outputPath(
-      ScanCompilerInvocation.getFrontendOptions().ScannerOutputDir);
+    if (binaryModulePath.empty())
+      return llvm::createStringError("failed to load bridging header " +
+                                     headerPath);
 
-  if (outputPath.empty())
-    outputPath = "/<compiler-generated>";
+    // Extract the embedded bridging header
+    auto moduleBuf = FS->getBufferForFile(binaryModulePath);
+    if (!moduleBuf)
+      return llvm::errorCodeToError(moduleBuf.getError());
 
-  llvm::sys::path::append(
-      outputPath, ScanCompilerInvocation.getFrontendOptions().ModuleName + "-" +
-                      ScanCompilerInvocation.getModuleScanningHash() +
-                      "-ChainedBridgingHeader.h");
+    auto content = extractEmbeddedBridgingHeaderContent(
+        std::move(*moduleBuf), /*headerPath=*/"", ScanASTContext);
+    if (!content)
+      return llvm::createStringError("can't load embedded header from " +
+                                     binaryModulePath);
 
-  llvm::SmallString<256> sourceBuf;
-  llvm::raw_svector_ostream outOS(sourceBuf);
+    outOS << "# 1 \"<module-" << moduleName
+          << "-embedded-bridging-header>\" 1\n";
+    outOS << content->getBuffer() << "\n";
+    return llvm::Error::success();
+  };
 
   // Iterate through all the modules and collect all the bridging header
   // and chain them into a single file. The allModules list is in the order of
   // discover, thus providing stable ordering for a deterministic generated
   // buffer.
-  auto FS = ScanASTContext.SourceMgr.getFileSystem();
-  for (const auto &moduleID: allModules) {
-    if (moduleID.Kind != ModuleDependencyKind::SwiftSource &&
-        moduleID.Kind != ModuleDependencyKind::SwiftBinary)
+  for (const auto &moduleID : allModules) {
+    if (moduleID.Kind != ModuleDependencyKind::SwiftBinary)
       continue;
 
     auto moduleDependencyInfo = cache.findKnownDependency(moduleID);
     if (auto *binaryMod = moduleDependencyInfo.getAsSwiftBinaryModule()) {
-      if (!binaryMod->headerImport.empty()) {
-        hasBridgingHeader = true;
-        if (FS->exists(binaryMod->headerImport)) {
-          outOS << "#include \"" << binaryMod->headerImport << "\"\n";
-        } else {
-          // Extract the embedded bridging header
-          auto moduleBuf = FS->getBufferForFile(binaryMod->compiledModulePath);
-          if (!moduleBuf)
-            return llvm::errorCodeToError(moduleBuf.getError());
-
-          auto content = extractEmbeddedBridgingHeaderContent(
-              std::move(*moduleBuf), ScanASTContext);
-          if (content.empty())
-            return llvm::createStringError("can't load embedded header from " +
-                                           binaryMod->compiledModulePath);
-
-          outOS << content << "\n";
-        }
-      }
-    } else if (auto *srcMod = moduleDependencyInfo.getAsSwiftSourceModule()) {
-      if (srcMod->textualModuleDetails.bridgingHeaderFile) {
-        hasBridgingHeader = true;
-        outOS << "#include \""
-              << *srcMod->textualModuleDetails.bridgingHeaderFile << "\"\n";
-      }
+      if (binaryMod->headerImport.empty())
+        continue;
+
+      if (auto E =
+              chainBridgingHeader(moduleID.ModuleName, binaryMod->headerImport,
+                                  binaryMod->compiledModulePath))
+        return E;
     }
   }
 
-  if (!hasBridgingHeader)
-    return llvm::Error::success();
+  // Handle bridging header in main module.
+  auto mainModuleDeps = cache.findKnownDependency(rootModuleID);
+  auto *mainModule = mainModuleDeps.getAsSwiftSourceModule();
+  assert(mainModule && "expect main module to be a swift source module");
+  std::unique_ptr<llvm::MemoryBuffer> sourceBuffer;
+  bool needChainedHeader = !chainedHeaderBuffer.empty();
+  if (!needChainedHeader) {
+    // There is no bridging header chained from dependencies.
+    // If main module also has no bridging header, ther is nothing to scan.
+    if (!mainModule->textualModuleDetails.bridgingHeaderFile)
+      return llvm::Error::success();
+
+    // Otherwise, there is no chaining needed. Just use the bridging header from
+    // main module.
+    if (auto headerBuffer = FS->getBufferForFile(
+            *mainModule->textualModuleDetails.bridgingHeaderFile))
+      sourceBuffer = std::move(*headerBuffer);
+    else
+      return llvm::errorCodeToError(headerBuffer.getError());
+  } else {
+    // There are bridging header needed to be chained. Append the bridging
+    // header from main module if needed and create use a new source buffer.
+    if (mainModule->textualModuleDetails.bridgingHeaderFile) {
+      if (auto E = chainBridgingHeader(
+              rootModuleID.ModuleName,
+              *mainModule->textualModuleDetails.bridgingHeaderFile, ""))
+        return E;
+    }
 
-  if (ScanCompilerInvocation.getFrontendOptions().WriteScannerOutput) {
-    auto outFile = outputBackend.createFile(outputPath);
-    if (!outFile)
-      return outFile.takeError();
-    *outFile << sourceBuf;
-    if (auto err = outFile->keep())
-      return err;
+    SmallString<256> outputPath(
+        ScanCompilerInvocation.getFrontendOptions().ScannerOutputDir);
+
+    if (outputPath.empty())
+      outputPath = "/<compiler-generated>";
+
+    // Use the hash of the file content to differentiate the chained header.
+    auto fileHash =
+        llvm::toString(llvm::APInt(64, llvm::hash_value(chainedHeaderBuffer)),
+                       36, /*Signed=*/false);
+    llvm::sys::path::append(
+        outputPath, ScanCompilerInvocation.getFrontendOptions().ModuleName +
+                        "-" + fileHash + "-ChainedBridgingHeader.h");
+
+    if (ScanCompilerInvocation.getFrontendOptions().WriteScannerOutput) {
+      llvm::vfs::OnDiskOutputBackend outputBackend;
+      auto outFile = outputBackend.createFile(outputPath);
+      if (!outFile)
+        return outFile.takeError();
+      *outFile << chainedHeaderBuffer;
+      if (auto err = outFile->keep())
+        return err;
+    }
+
+    sourceBuffer =
+        llvm::MemoryBuffer::getMemBufferCopy(chainedHeaderBuffer, outputPath);
   }
 
-  auto sourceBuffer =
-      llvm::MemoryBuffer::getMemBufferCopy(sourceBuf, outputPath);
   // Scan and update the main module dependency.
-  auto mainModuleDeps = cache.findKnownDependency(rootModuleID);
   ModuleDependencyIDSetVector headerClangModuleDependencies;
   std::optional<std::string> includeTreeID;
   auto err = withDependencyScanningWorker(
       [&](ModuleDependencyScanningWorker *ScanningWorker) -> llvm::Error {
-        auto clangImporter = static_cast<ClangImporter *>(
-            ScanningWorker->clangScannerModuleLoader.get());
         std::vector<std::string> headerFileInputs;
         std::vector<std::string> bridgingHeaderCommandLine;
-        if (clangImporter->getHeaderDependencies(
+        std::vector<std::string> visibleClangModules;
+        auto lookupModuleOutput = [this](const auto &cd, auto mok) -> auto {
+          return clangModuleOutputPathLookup(cd, mok);
+        };
+        auto headerScanResult =
+            ScanningWorker->scanHeaderDependenciesOfSwiftModule(
                 rootModuleID, /*headerPath=*/std::nullopt,
-                sourceBuffer->getMemBufferRef(),
-                ScanningWorker->clangScanningTool, cache,
-                headerClangModuleDependencies, headerFileInputs,
-                bridgingHeaderCommandLine, includeTreeID))
+                sourceBuffer->getMemBufferRef(), lookupModuleOutput,
+                cache.getAlreadySeenClangModules());
+
+        if (!headerScanResult)
           return llvm::createStringError(
-              "failed to scan generated bridging header " + outputPath);
+              "failed to scan generated bridging header " +
+              sourceBuffer->getBufferIdentifier());
+
+        // Record module dependencies for each new module we found.
+        cache.recordClangDependencies(
+            headerScanResult->ModuleGraph, ScanASTContext.Diags,
+            [this](auto &clangDep) {
+              return bridgeClangModuleDependency(clangDep);
+            });
+        llvm::copy(headerScanResult->FileDeps,
+                   std::back_inserter(headerFileInputs));
+        auto bridgedDependencyIDs =
+            llvm::map_range(headerScanResult->ClangModuleDeps, [](auto &input) {
+              return ModuleDependencyID{input.ModuleName,
+                                        ModuleDependencyKind::Clang};
+            });
+        headerClangModuleDependencies.insert(bridgedDependencyIDs.begin(),
+                                             bridgedDependencyIDs.end());
+
+        // Update visible module set
+        if (auto TreeID = headerScanResult->IncludeTreeID)
+          includeTreeID = TreeID;
+        ClangImporter::getBridgingHeaderOptions(
+            ScanASTContext, *headerScanResult, bridgingHeaderCommandLine);
 
         cache.setHeaderClangDependencies(
             rootModuleID, headerClangModuleDependencies.getArrayRef());
@@ -1531,9 +1828,28 @@ llvm::Error ModuleDependencyScanner::performBridgingHeaderChaining(
         }
         mainModuleDeps.updateBridgingHeaderCommandLine(
             bridgingHeaderCommandLine);
+        if (needChainedHeader) {
+          // As only the chained bridging header is scanned, the dependency will
+          // not include the original bridging header passed by user. Fixup the
+          // headerFileInputs to include original bridging header and not
+          // include the generated header so build system can correctly computes
+          // the dependencies.
+          auto generated =
+              llvm::find(headerFileInputs, sourceBuffer->getBufferIdentifier());
+          if (generated != headerFileInputs.end()) {
+            if (mainModule->textualModuleDetails.bridgingHeaderFile)
+              *generated = *mainModule->textualModuleDetails.bridgingHeaderFile;
+            else
+              headerFileInputs.erase(generated);
+          }
+        }
         mainModuleDeps.setHeaderSourceFiles(headerFileInputs);
-        mainModuleDeps.setChainedBridgingHeaderBuffer(
-            outputPath, sourceBuffer->getBuffer());
+        if (needChainedHeader)
+          mainModuleDeps.setChainedBridgingHeaderBuffer(
+              sourceBuffer->getBufferIdentifier(), sourceBuffer->getBuffer());
+        // Update the set of visible Clang modules
+        mainModuleDeps.addVisibleClangModules(headerScanResult->VisibleModules);
+
         // Update the dependency in the cache
         cache.updateDependency(rootModuleID, mainModuleDeps);
         return llvm::Error::success();
@@ -1551,3 +1867,307 @@ llvm::Error ModuleDependencyScanner::performBridgingHeaderChaining(
 
   return llvm::Error::success();
 }
+
+std::string ModuleDependencyScanner::remapPath(StringRef Path) const {
+  if (!PrefixMapper)
+    return Path.str();
+  return PrefixMapper->mapToString(Path);
+}
+
+ModuleDependencyInfo ModuleDependencyScanner::bridgeClangModuleDependency(
+    const clang::tooling::dependencies::ModuleDeps &clangModuleDep) {
+  // File dependencies for this module.
+  std::vector<std::string> fileDeps;
+  clangModuleDep.forEachFileDep(
+      [&fileDeps](StringRef fileDep) { fileDeps.emplace_back(fileDep); });
+
+  std::vector<std::string> swiftArgs;
+  auto addClangArg = [&](Twine arg) {
+    swiftArgs.push_back("-Xcc");
+    swiftArgs.push_back(arg.str());
+  };
+
+  // We are using Swift frontend mode.
+  swiftArgs.push_back("-frontend");
+
+  // Swift frontend action: -emit-pcm
+  swiftArgs.push_back("-emit-pcm");
+  swiftArgs.push_back("-module-name");
+  swiftArgs.push_back(clangModuleDep.ID.ModuleName);
+
+  auto pcmPath = clangModuleOutputPathLookup(
+      clangModuleDep,
+      clang::tooling::dependencies::ModuleOutputKind::ModuleFile);
+  swiftArgs.push_back("-o");
+  swiftArgs.push_back(pcmPath);
+
+  // Ensure that the resulting PCM build invocation uses Clang frontend
+  // directly
+  swiftArgs.push_back("-direct-clang-cc1-module-build");
+
+  // Swift frontend option for input file path (Foo.modulemap).
+  swiftArgs.push_back(remapPath(clangModuleDep.ClangModuleMapFile));
+
+  auto invocation = clangModuleDep.getUnderlyingCompilerInvocation();
+  // Clear some options from clang scanner.
+  invocation.getMutFrontendOpts().ModuleCacheKeys.clear();
+  invocation.getMutFrontendOpts().PathPrefixMappings.clear();
+  invocation.getMutFrontendOpts().OutputFile.clear();
+
+  // Reset CASOptions since that should be coming from swift.
+  invocation.getMutCASOpts() = clang::CASOptions();
+  invocation.getMutFrontendOpts().CASIncludeTreeID.clear();
+
+  // FIXME: workaround for rdar://105684525: find the -ivfsoverlay option
+  // from clang scanner and pass to swift.
+  if (!ScanASTContext.CASOpts.EnableCaching) {
+    auto &overlayFiles = invocation.getMutHeaderSearchOpts().VFSOverlayFiles;
+    for (auto overlay : overlayFiles) {
+      swiftArgs.push_back("-vfsoverlay");
+      swiftArgs.push_back(overlay);
+    }
+  }
+
+  // Add args reported by the scanner.
+  auto clangArgs = invocation.getCC1CommandLine();
+  llvm::for_each(clangArgs, addClangArg);
+
+  // CASFileSystemRootID.
+  std::string RootID = clangModuleDep.CASFileSystemRootID
+                           ? clangModuleDep.CASFileSystemRootID.value()
+                           : "";
+
+  std::string IncludeTree =
+      clangModuleDep.IncludeTreeID ? *clangModuleDep.IncludeTreeID : "";
+
+  ScanASTContext.CASOpts.enumerateCASConfigurationFlags(
+      [&](StringRef Arg) { swiftArgs.push_back(Arg.str()); });
+
+  if (!IncludeTree.empty()) {
+    swiftArgs.push_back("-clang-include-tree-root");
+    swiftArgs.push_back(IncludeTree);
+  }
+  std::string mappedPCMPath = remapPath(pcmPath);
+
+  std::vector<LinkLibrary> LinkLibraries;
+  for (const auto &ll : clangModuleDep.LinkLibraries)
+    LinkLibraries.emplace_back(ll.Library,
+                               ll.IsFramework ? LibraryKind::Framework
+                                              : LibraryKind::Library,
+                               /*static=*/false);
+
+  // Module-level dependencies.
+  llvm::StringSet<> alreadyAddedModules;
+  auto bridgedDependencyInfo = ModuleDependencyInfo::forClangModule(
+      pcmPath, mappedPCMPath, clangModuleDep.ClangModuleMapFile,
+      clangModuleDep.ID.ContextHash, swiftArgs, fileDeps, LinkLibraries, RootID,
+      IncludeTree, /*module-cache-key*/ "", clangModuleDep.IsSystem);
+
+  std::vector<ModuleDependencyID> directDependencyIDs;
+  for (const auto &moduleName : clangModuleDep.ClangModuleDeps) {
+    // FIXME: This assumes, conservatively, that all Clang module imports
+    // are exported. We need to fix this once the clang scanner gains the
+    // appropriate API to query this.
+    bridgedDependencyInfo.addModuleImport(
+        moduleName.ModuleName, /* isExported */ true, AccessLevel::Public,
+        &alreadyAddedModules);
+    // It is safe to assume that all dependencies of a Clang module are Clang
+    // modules.
+    directDependencyIDs.push_back(
+        {moduleName.ModuleName, ModuleDependencyKind::Clang});
+  }
+  bridgedDependencyInfo.setImportedClangDependencies(directDependencyIDs);
+  return bridgedDependencyInfo;
+}
+
+void ModuleDependencyIssueReporter::diagnoseModuleNotFoundFailure(
+    const ScannerImportStatementInfo &moduleImport,
+    const ModuleDependenciesCache &cache,
+    std::optional<ModuleDependencyID> dependencyOf,
+    std::optional<std::pair<ModuleDependencyID, std::string>>
+        resolvingSerializedSearchPath,
+    std::optional<
+        std::vector<SwiftModuleScannerQueryResult::IncompatibleCandidate>>
+        foundIncompatibleCandidates) {
+  // Do not report the same failure multiple times. This can
+  // happen, for example, when we first report that a valid Swift module is
+  // missing and then look it up again as a Swift overlay of its underlying
+  // Clang module.
+  if (ReportedMissing.find(moduleImport.importIdentifier) !=
+      ReportedMissing.end())
+    return;
+
+  SourceLoc importLoc = SourceLoc();
+  if (!moduleImport.importLocations.empty()) {
+    auto locInfo = moduleImport.importLocations[0];
+    importLoc = Diagnostics.SourceMgr.getLocFromExternalSource(
+        locInfo.bufferIdentifier, locInfo.lineNumber, locInfo.columnNumber);
+  }
+
+  // Emit the top-level error diagnostic, which is one of 3 possibilities:
+  // 1. Module dependency can not be found but could be resolved if using search
+  // paths serialized into some binary Swift module dependency
+  //
+  // 2. Swift Module dependency can not be found but we did find binary Swift
+  // module candidates for this module which are not compatible with current
+  // compilation
+  //
+  // 3. All other generic "module not found" cases
+  if (resolvingSerializedSearchPath) {
+    Diagnostics.diagnose(
+        importLoc,
+        diag::dependency_scan_module_not_found_on_specified_search_paths,
+        moduleImport.importIdentifier);
+    Diagnostics.diagnose(importLoc, diag::inherited_search_path_resolves_module,
+                         moduleImport.importIdentifier,
+                         resolvingSerializedSearchPath->first.ModuleName,
+                         resolvingSerializedSearchPath->second);
+  } else if (foundIncompatibleCandidates) {
+    Diagnostics.diagnose(
+        importLoc, diag::dependency_scan_compatible_swift_module_not_found,
+        moduleImport.importIdentifier);
+    for (const auto &candidate : *foundIncompatibleCandidates)
+      Diagnostics.diagnose(importLoc,
+                           diag::dependency_scan_incompatible_module_found,
+                           candidate.path, candidate.incompatibilityReason);
+  } else
+    Diagnostics.diagnose(importLoc, diag::dependency_scan_module_not_found,
+                         moduleImport.importIdentifier);
+
+  // Emit notes for every link in the dependency chain from the root
+  // module-under-scan to the module whose import failed to resolve.
+  if (dependencyOf.has_value()) {
+    auto path = findPathToDependency(dependencyOf.value(), cache);
+    // We may fail to construct a path in some cases, such as a Swift overlay of
+    // a Clang module dependnecy.
+    if (path.empty())
+      path = {dependencyOf.value()};
+
+    for (auto it = path.rbegin(), end = path.rend(); it != end; ++it) {
+      const auto &entry = *it;
+      auto optionalEntryNode = cache.findDependency(entry);
+      assert(optionalEntryNode.has_value());
+      auto entryNode = optionalEntryNode.value();
+      std::string moduleFilePath = "";
+      bool isClang = false;
+      switch (entryNode->getKind()) {
+      case swift::ModuleDependencyKind::SwiftSource:
+        Diagnostics.diagnose(importLoc,
+                             diag::dependency_as_imported_by_main_module,
+                             entry.ModuleName);
+        continue;
+      case swift::ModuleDependencyKind::SwiftInterface:
+        moduleFilePath =
+            entryNode->getAsSwiftInterfaceModule()->swiftInterfaceFile;
+        break;
+      case swift::ModuleDependencyKind::SwiftBinary:
+        moduleFilePath =
+            entryNode->getAsSwiftBinaryModule()->compiledModulePath;
+        break;
+      case swift::ModuleDependencyKind::Clang:
+        moduleFilePath = entryNode->getAsClangModule()->moduleMapFile;
+        isClang = true;
+        break;
+      default:
+        llvm_unreachable("Unexpected dependency kind");
+      }
+
+      Diagnostics.diagnose(importLoc, diag::dependency_as_imported_by,
+                           entry.ModuleName, moduleFilePath, isClang);
+    }
+  }
+
+  // Emit notes for every other known location where the failed-to-resolve
+  // module is imported.
+  if (moduleImport.importLocations.size() > 1) {
+    for (size_t i = 1; i < moduleImport.importLocations.size(); ++i) {
+      auto locInfo = moduleImport.importLocations[i];
+      auto importLoc = Diagnostics.SourceMgr.getLocFromExternalSource(
+          locInfo.bufferIdentifier, locInfo.lineNumber, locInfo.columnNumber);
+      Diagnostics.diagnose(importLoc, diag::unresolved_import_location);
+    }
+  }
+
+  ReportedMissing.insert(moduleImport.importIdentifier);
+}
+
+void ModuleDependencyIssueReporter::diagnoseFailureOnOnlyIncompatibleCandidates(
+    const ScannerImportStatementInfo &moduleImport,
+    const std::vector<SwiftModuleScannerQueryResult::IncompatibleCandidate>
+        &candidates,
+    const ModuleDependenciesCache &cache,
+    std::optional<ModuleDependencyID> dependencyOf) {
+  // If no incompatible candidates were discovered,
+  // the dependency scanning failure will be caught downstream.
+  if (candidates.empty())
+    return;
+
+  diagnoseModuleNotFoundFailure(moduleImport, cache, dependencyOf,
+                                /* resolvingSerializedSearchPath */ std::nullopt,
+                                candidates);
+}
+
+void ModuleDependencyIssueReporter::warnOnIncompatibleCandidates(
+    StringRef moduleName,
+    const std::vector<SwiftModuleScannerQueryResult::IncompatibleCandidate>
+        &candidates) {
+  // If the dependency was ultimately resolved to a different
+  // binary module or a textual module, emit warnings about
+  // having encountered incompatible binary modules.
+  for (const auto &candidate : candidates)
+    Diagnostics.diagnose(SourceLoc(), diag::dependency_scan_module_incompatible,
+                         candidate.path, candidate.incompatibilityReason);
+}
+
+std::optional<std::pair<ModuleDependencyID, std::string>>
+ModuleDependencyScanner::attemptToFindResolvingSerializedSearchPath(
+    const ScannerImportStatementInfo &moduleImport,
+    const ModuleDependenciesCache &cache) {
+  std::set<ModuleDependencyID> binarySwiftModuleDepIDs =
+      collectBinarySwiftDeps(cache);
+
+  std::optional<std::pair<ModuleDependencyID, std::string>> result;
+  for (const auto &binaryDepID : binarySwiftModuleDepIDs) {
+    auto binaryModInfo =
+        cache.findKnownDependency(binaryDepID).getAsSwiftBinaryModule();
+    assert(binaryModInfo);
+    if (binaryModInfo->serializedSearchPaths.empty())
+      continue;
+
+    // Note: this will permanently mutate this worker with additional search
+    // paths. That's fine because we are diagnosing a scan failure here, but
+    // worth being aware of.
+    result = withDependencyScanningWorker(
+        [&](ModuleDependencyScanningWorker *ScanningWorker)
+            -> std::optional<std::pair<ModuleDependencyID, std::string>> {
+          for (const auto &sp : binaryModInfo->serializedSearchPaths)
+            ScanningWorker->workerASTContext->addSearchPath(
+                sp.Path, sp.IsFramework, sp.IsSystem);
+
+          auto importIdentifier =
+              getModuleImportIdentifier(moduleImport.importIdentifier);
+          SwiftModuleScannerQueryResult swiftResult =
+              ScanningWorker->scanFilesystemForSwiftModuleDependency(
+                  importIdentifier, /* isTestableImport */ false);
+          if (swiftResult.foundDependencyInfo)
+            return std::make_pair(
+                binaryDepID,
+                swiftResult.foundDependencyInfo->getModuleDefiningPath());
+
+          auto clangResult =
+              ScanningWorker->scanFilesystemForClangModuleDependency(
+                  importIdentifier,
+                  [this](const auto &cd, auto mok) -> std::string {
+                    return clangModuleOutputPathLookup(cd, mok);
+                  }, {});
+          if (clangResult)
+            return std::make_pair(
+                binaryDepID, clangResult->ModuleGraph[0].ClangModuleMapFile);
+          return std::nullopt;
+        });
+    if (result)
+      break;
+  }
+
+  return result;
+}
diff --git a/lib/DependencyScan/ScanDependencies.cpp b/lib/DependencyScan/ScanDependencies.cpp
index 12d900ffd7c54..b19ade93112a7 100644
--- a/lib/DependencyScan/ScanDependencies.cpp
+++ b/lib/DependencyScan/ScanDependencies.cpp
@@ -44,8 +44,9 @@
 #include "swift/Frontend/Frontend.h"
 #include "swift/Frontend/FrontendOptions.h"
 #include "swift/Frontend/ModuleInterfaceLoader.h"
+#include "swift/Frontend/SerializedDiagnosticConsumer.h"
 #include "swift/Strings.h"
-#include "clang/Basic/Module.h"
+#include "clang/CAS/IncludeTree.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SetOperations.h"
 #include "llvm/ADT/SetVector.h"
@@ -69,7 +70,6 @@
 #include <sstream>
 #include <stack>
 #include <string>
-#include <algorithm>
 
 using namespace swift;
 using namespace swift::dependencies;
@@ -81,28 +81,23 @@ namespace {
 class ExplicitModuleDependencyResolver {
 public:
   ExplicitModuleDependencyResolver(
-      const ModuleDependencyID &moduleID, ModuleDependenciesCache &cache,
-      CompilerInstance &instance, std::optional<SwiftDependencyTracker> tracker)
-      : moduleID(moduleID), cache(cache), instance(instance),
+      const ModuleDependencyID &moduleID,
+      const ModuleDependencyScanner &scanner,
+      ModuleDependenciesCache &cache, CompilerInstance &instance,
+      std::optional<SwiftDependencyTracker> tracker)
+      : moduleID(moduleID), scanner(scanner), cache(cache), instance(instance),
         resolvingDepInfo(cache.findKnownDependency(moduleID)),
         tracker(std::move(tracker)) {
     // Copy commandline.
     commandline = resolvingDepInfo.getCommandline();
   }
 
-  llvm::Error
-  resolve(const std::set<ModuleDependencyID> &dependencies,
-          std::optional<std::set<ModuleDependencyID>> bridgingHeaderDeps) {
-    // No need to resolve dependency for placeholder.
-    if (moduleID.Kind == ModuleDependencyKind::SwiftPlaceholder)
-      return llvm::Error::success();
-
+  // Resolve the dependencies for the current moduleID. Return true on error.
+  bool resolve(const std::set<ModuleDependencyID> &dependencies,
+               std::optional<std::set<ModuleDependencyID>> bridgingHeaderDeps) {
     // If the dependency is already finalized, nothing needs to be done.
     if (resolvingDepInfo.isFinalized())
-      return llvm::Error::success();
-
-    if (auto ID = resolvingDepInfo.getClangIncludeTree())
-      includeTrees.push_back(*ID);
+      return false;
 
     for (const auto &depModuleID : dependencies) {
       const auto &depInfo = cache.findKnownDependency(depModuleID);
@@ -110,37 +105,27 @@ class ExplicitModuleDependencyResolver {
       case swift::ModuleDependencyKind::SwiftInterface: {
         auto interfaceDepDetails = depInfo.getAsSwiftInterfaceModule();
         assert(interfaceDepDetails && "Expected Swift Interface dependency.");
-        if (auto err = handleSwiftInterfaceModuleDependency(
-                depModuleID, *interfaceDepDetails))
-          return err;
+        if (handleSwiftInterfaceModuleDependency(depModuleID,
+                                                 *interfaceDepDetails))
+          return true;
       } break;
       case swift::ModuleDependencyKind::SwiftBinary: {
         auto binaryDepDetails = depInfo.getAsSwiftBinaryModule();
         assert(binaryDepDetails && "Expected Swift Binary Module dependency.");
-        if (auto err = handleSwiftBinaryModuleDependency(depModuleID,
-                                                         *binaryDepDetails))
-          return err;
-      } break;
-      case swift::ModuleDependencyKind::SwiftPlaceholder: {
-        auto placeholderDetails = depInfo.getAsPlaceholderDependencyModule();
-        assert(placeholderDetails && "Expected Swift Placeholder dependency.");
-        if (auto err = handleSwiftPlaceholderModuleDependency(
-                depModuleID, *placeholderDetails))
-          return err;
+        if (handleSwiftBinaryModuleDependency(depModuleID, *binaryDepDetails))
+          return true;
       } break;
       case swift::ModuleDependencyKind::Clang: {
         auto clangDepDetails = depInfo.getAsClangModule();
         assert(clangDepDetails && "Expected Clang Module dependency.");
-        if (auto err =
-                handleClangModuleDependency(depModuleID, *clangDepDetails))
-          return err;
+        if (handleClangModuleDependency(depModuleID, *clangDepDetails))
+          return true;
       } break;
       case swift::ModuleDependencyKind::SwiftSource: {
         auto sourceDepDetails = depInfo.getAsSwiftSourceModule();
         assert(sourceDepDetails && "Expected Swift Source Module dependency.");
-        if (auto err = handleSwiftSourceModuleDependency(depModuleID,
-                                                         *sourceDepDetails))
-          return err;
+        if (handleSwiftSourceModuleDependency(depModuleID, *sourceDepDetails))
+          return true;
       } break;
       default:
         llvm_unreachable("Unhandled dependency kind.");
@@ -149,11 +134,11 @@ class ExplicitModuleDependencyResolver {
 
     // Update bridging header build command if there is a bridging header
     // dependency.
-    if (auto E = addBridgingHeaderDeps(resolvingDepInfo))
-      return E;
+    if (addBridgingHeaderDeps(resolvingDepInfo))
+      return true;
+
     if (bridgingHeaderDeps) {
-      bridgingHeaderBuildCmd =
-          resolvingDepInfo.getBridgingHeaderCommandline();
+      bridgingHeaderBuildCmd = resolvingDepInfo.getBridgingHeaderCommandline();
       for (auto bridgingDep : *bridgingHeaderDeps) {
         auto &dep = cache.findKnownDependency(bridgingDep);
         auto *clangDep = dep.getAsClangModule();
@@ -179,31 +164,28 @@ class ExplicitModuleDependencyResolver {
     // Update the dependency in the cache with the modified command-line.
     if (resolvingDepInfo.isSwiftInterfaceModule() ||
         resolvingDepInfo.isClangModule()) {
-      if (cache.getScanService().hasPathMapping())
+      if (scanner.hasPathMapping())
         commandline =
             remapPathsFromCommandLine(commandline, [&](StringRef path) {
-              return cache.getScanService().remapPath(path);
+              return scanner.remapPath(path);
             });
       addDeterministicCheckFlags(commandline);
     }
 
     auto dependencyInfoCopy = resolvingDepInfo;
-    if (auto err = finalize(dependencyInfoCopy, swiftInterfaceOutputPath))
-      return err;
+    if (finalize(dependencyInfoCopy, swiftInterfaceOutputPath))
+      return true;
 
     dependencyInfoCopy.setIsFinalized(true);
     cache.updateDependency(moduleID, dependencyInfoCopy);
-    return llvm::Error::success();
+    return false;
   }
 
 private:
   // Finalize the resolving dependency info.
-  llvm::Error finalize(ModuleDependencyInfo &depInfo,
-                       const SwiftInterfaceModuleOutputPathResolution::ResultTy
-                           &swiftInterfaceModuleOutputPath) {
-    if (resolvingDepInfo.isSwiftPlaceholderModule())
-      return llvm::Error::success();
-
+  bool finalize(ModuleDependencyInfo &depInfo,
+                const SwiftInterfaceModuleOutputPathResolution::ResultTy
+                    &swiftInterfaceModuleOutputPath) {
     if (resolvingDepInfo.isSwiftInterfaceModule())
       depInfo.setOutputPathAndHash(
           swiftInterfaceModuleOutputPath.outputPath.str().str(),
@@ -214,9 +196,23 @@ class ExplicitModuleDependencyResolver {
       depInfo.addMacroDependency(macro.first(), macro.second.LibraryPath,
                                  macro.second.ExecutablePath);
 
+    bool needPathRemapping = instance.getInvocation()
+                                 .getSearchPathOptions()
+                                 .ResolvedPluginVerification &&
+                             scanner.hasPathMapping();
+    auto mapPath = [&](StringRef path) {
+      if (!needPathRemapping)
+        return path.str();
+
+      return scanner.remapPath(path);
+    };
+    if (needPathRemapping)
+      commandline.push_back("-resolved-plugin-verification");
+
     for (auto &macro : depInfo.getMacroDependencies()) {
-      std::string arg = macro.second.LibraryPath + "#" +
-                        macro.second.ExecutablePath + "#" + macro.first;
+      std::string arg = mapPath(macro.second.LibraryPath) + "#" +
+                        mapPath(macro.second.ExecutablePath) + "#" +
+                        macro.first;
       commandline.push_back("-load-resolved-plugin");
       commandline.push_back(arg);
     }
@@ -229,14 +225,14 @@ class ExplicitModuleDependencyResolver {
       depInfo.updateBridgingHeaderCommandLine(bridgingHeaderBuildCmd);
     if (!resolvingDepInfo.isSwiftBinaryModule()) {
       depInfo.updateCommandLine(commandline);
-      if (auto err = updateModuleCacheKey(depInfo))
-        return err;
+      if (updateModuleCacheKey(depInfo))
+        return true;
     }
 
-    return llvm::Error::success();
+    return false;
   }
 
-  llvm::Error handleSwiftInterfaceModuleDependency(
+  bool handleSwiftInterfaceModuleDependency(
       ModuleDependencyID depModuleID,
       const SwiftInterfaceModuleDependenciesStorage &interfaceDepDetails) {
     if (!resolvingDepInfo.isSwiftSourceModule()) {
@@ -247,10 +243,10 @@ class ExplicitModuleDependencyResolver {
                             "=" + path);
     }
     addMacroDependencies(depModuleID, interfaceDepDetails);
-    return llvm::Error::success();
+    return false;
   }
 
-  llvm::Error handleSwiftBinaryModuleDependency(
+  bool handleSwiftBinaryModuleDependency(
       ModuleDependencyID depModuleID,
       const SwiftBinaryModuleDependencyStorage &binaryDepDetails) {
     if (!resolvingDepInfo.isSwiftSourceModule()) {
@@ -271,24 +267,14 @@ class ExplicitModuleDependencyResolver {
         commandline.push_back("-Xcc");
         commandline.push_back(
             "-fmodule-map-file=" +
-            cache.getScanService().remapPath(
-                bridgingHeaderDepModuleDetails->moduleMapFile));
+            scanner.remapPath(bridgingHeaderDepModuleDetails->moduleMapFile));
       }
     }
     addMacroDependencies(depModuleID, binaryDepDetails);
-    return llvm::Error::success();
-  }
-
-  llvm::Error handleSwiftPlaceholderModuleDependency(
-      ModuleDependencyID depModuleID,
-      const SwiftPlaceholderModuleDependencyStorage &placeholderDetails) {
-    if (!resolvingDepInfo.isSwiftSourceModule())
-      commandline.push_back("-swift-module-file=" + depModuleID.ModuleName +
-                            "=" + placeholderDetails.compiledModulePath);
-    return llvm::Error::success();
+    return false;
   }
 
-  llvm::Error handleClangModuleDependency(
+  bool handleClangModuleDependency(
       ModuleDependencyID depModuleID,
       const ClangModuleDependencyStorage &clangDepDetails) {
     if (!resolvingDepInfo.isSwiftSourceModule()) {
@@ -308,32 +294,32 @@ class ExplicitModuleDependencyResolver {
     }
 
     // Collect CAS deppendencies from clang modules.
-    if (!clangDepDetails.CASFileSystemRootID.empty())
-      rootIDs.push_back(clangDepDetails.CASFileSystemRootID);
-    if (!clangDepDetails.CASClangIncludeTreeRootID.empty())
-      includeTrees.push_back(clangDepDetails.CASClangIncludeTreeRootID);
+    if (!clangDepDetails.CASClangIncludeTreeRootID.empty()) {
+      if (addIncludeTree(clangDepDetails.CASClangIncludeTreeRootID))
+        return true;
+    }
 
     collectUsedVFSOverlay(clangDepDetails);
 
-    return llvm::Error::success();
+    return false;
   }
 
-  llvm::Error handleSwiftSourceModuleDependency(
+  bool handleSwiftSourceModuleDependency(
       ModuleDependencyID depModuleID,
       const SwiftSourceModuleDependenciesStorage &sourceDepDetails) {
     addMacroDependencies(depModuleID, sourceDepDetails);
     return addBridgingHeaderDeps(sourceDepDetails);
   }
 
-  llvm::Error addBridgingHeaderDeps(const ModuleDependencyInfo &depInfo) {
+  bool addBridgingHeaderDeps(const ModuleDependencyInfo &depInfo) {
     auto sourceDepDetails = depInfo.getAsSwiftSourceModule();
     if (!sourceDepDetails)
-      return llvm::Error::success();
+      return false;
 
     return addBridgingHeaderDeps(*sourceDepDetails);
   }
 
-  llvm::Error addBridgingHeaderDeps(
+  bool addBridgingHeaderDeps(
       const SwiftSourceModuleDependenciesStorage &sourceDepDetails) {
     if (sourceDepDetails.textualModuleDetails.CASBridgingHeaderIncludeTreeRootID
             .empty()) {
@@ -345,14 +331,16 @@ class ExplicitModuleDependencyResolver {
             tracker->trackFile(file);
           auto bridgeRoot = tracker->createTreeFromDependencies();
           if (!bridgeRoot)
-            return bridgeRoot.takeError();
-          fileListIDs.push_back(bridgeRoot->getID().toString());
+            return diagnoseCASFSCreationError(bridgeRoot.takeError());
+
+          fileListRefs.push_back(bridgeRoot->getRef());
         }
       }
-    } else
-      includeTrees.push_back(sourceDepDetails.textualModuleDetails
-                                 .CASBridgingHeaderIncludeTreeRootID);
-    return llvm::Error::success();
+    } else if (addIncludeTree(sourceDepDetails.textualModuleDetails
+                                  .CASBridgingHeaderIncludeTreeRootID))
+      return true;
+
+    return false;
   };
 
   void addMacroDependencies(ModuleDependencyID moduleID,
@@ -371,7 +359,6 @@ class ExplicitModuleDependencyResolver {
   };
   static bool isXCCArg(StringRef arg) { return arg == "-Xcc"; };
 
-
   void
   collectUsedVFSOverlay(const ClangModuleDependencyStorage &clangDepDetails) {
     // true if the previous argument was the dash-option of an option pair
@@ -467,28 +454,27 @@ class ExplicitModuleDependencyResolver {
     return;
   }
 
-  llvm::Error collectCASDependencies(ModuleDependencyInfo &dependencyInfoCopy) {
+  bool collectCASDependencies(ModuleDependencyInfo &dependencyInfoCopy) {
     if (!instance.getInvocation().getCASOptions().EnableCaching)
-      return llvm::Error::success();
+      return false;
 
     // Collect CAS info from current resolving module.
     if (auto *sourceDep = resolvingDepInfo.getAsSwiftSourceModule()) {
       tracker->startTracking();
-      llvm::for_each(
-          sourceDep->sourceFiles,
-          [this](const std::string &file) { tracker->trackFile(file); });
+      llvm::for_each(sourceDep->sourceFiles, [this](const std::string &file) {
+        tracker->trackFile(file);
+      });
       llvm::for_each(
           sourceDep->auxiliaryFiles,
           [this](const std::string &file) { tracker->trackFile(file); });
-      llvm::for_each(sourceDep->macroDependencies, [this](const auto &entry) {
-        tracker->trackFile(entry.second.LibraryPath);
-      });
+      llvm::for_each(dependencyInfoCopy.getMacroDependencies(),
+                     [this](const auto &entry) {
+                       tracker->trackFile(entry.second.LibraryPath);
+                     });
       auto root = tracker->createTreeFromDependencies();
       if (!root)
-        return root.takeError();
-      auto rootID = root->getID().toString();
-      dependencyInfoCopy.updateCASFileSystemRootID(rootID);
-      fileListIDs.push_back(rootID);
+        return diagnoseCASFSCreationError(root.takeError());
+      fileListRefs.push_back(root->getRef());
     } else if (auto *textualDep =
                    resolvingDepInfo.getAsSwiftInterfaceModule()) {
       tracker->startTracking();
@@ -496,52 +482,38 @@ class ExplicitModuleDependencyResolver {
       llvm::for_each(
           textualDep->auxiliaryFiles,
           [this](const std::string &file) { tracker->trackFile(file); });
-      llvm::for_each(textualDep->macroDependencies,
+      llvm::for_each(dependencyInfoCopy.getMacroDependencies(),
                      [this](const auto &entry) {
                        tracker->trackFile(entry.second.LibraryPath);
                      });
       auto root = tracker->createTreeFromDependencies();
       if (!root)
-        return root.takeError();
-      auto rootID = root->getID().toString();
-      dependencyInfoCopy.updateCASFileSystemRootID(rootID);
-      fileListIDs.push_back(rootID);
+        return diagnoseCASFSCreationError(root.takeError());
+      fileListRefs.push_back(root->getRef());
     }
 
     // Update build command line.
     if (resolvingDepInfo.isSwiftInterfaceModule() ||
         resolvingDepInfo.isSwiftSourceModule()) {
       // Update with casfs option.
-      for (auto rootID : rootIDs) {
-        commandline.push_back("-cas-fs");
-        commandline.push_back(rootID);
-      }
-
-      for (auto tree : includeTrees) {
-        commandline.push_back("-clang-include-tree-root");
-        commandline.push_back(tree);
-      }
-
-      for (auto list : fileListIDs) {
-        commandline.push_back("-clang-include-tree-filelist");
-        commandline.push_back(list);
-      }
+      if (computeCASFileSystem(dependencyInfoCopy))
+        return true;
     }
 
     // Compute and update module cache key.
     if (auto *binaryDep = dependencyInfoCopy.getAsSwiftBinaryModule()) {
-      if (auto E = setupBinaryCacheKey(binaryDep->compiledModulePath,
-                                       dependencyInfoCopy))
-        return E;
+      if (setupBinaryCacheKey(binaryDep->compiledModulePath,
+                              dependencyInfoCopy))
+        return true;
     }
-    return llvm::Error::success();
+    return false;
   }
 
-  llvm::Error updateModuleCacheKey(ModuleDependencyInfo &depInfo) {
+  bool updateModuleCacheKey(ModuleDependencyInfo &depInfo) {
     if (!instance.getInvocation().getCASOptions().EnableCaching)
-      return llvm::Error::success();
+      return false;
 
-    auto &CAS = cache.getScanService().getCAS();
+    auto &CAS = scanner.getCAS();
     auto commandLine = depInfo.getCommandline();
     std::vector<const char *> Args;
     if (commandLine.size() > 1)
@@ -549,40 +521,67 @@ class ExplicitModuleDependencyResolver {
         Args.push_back(c.c_str());
 
     auto base = createCompileJobBaseCacheKey(CAS, Args);
-    if (!base)
-      return base.takeError();
+    if (!base) {
+      instance.getDiags().diagnose(SourceLoc(), diag::error_cache_key_creation,
+                                   moduleID.ModuleName,
+                                   toString(base.takeError()));
+      return true;
+    }
 
     // Module compilation commands always have only one input and the input
     // index is always 0.
     auto key = createCompileJobCacheKeyForOutput(CAS, *base, /*InputIndex=*/0);
-    if (!key)
-      return key.takeError();
+    if (!key) {
+      instance.getDiags().diagnose(SourceLoc(), diag::error_cache_key_creation,
+                                   moduleID.ModuleName,
+                                   toString(key.takeError()));
+      return true;
+    }
 
     depInfo.updateModuleCacheKey(CAS.getID(*key).toString());
-    return llvm::Error::success();
+    return false;
   }
 
-  llvm::Error setupBinaryCacheKey(StringRef path,
-                                  ModuleDependencyInfo &depInfo) {
-    auto &CASFS = cache.getScanService().getSharedCachingFS();
-    auto &CAS = cache.getScanService().getCAS();
+  bool setupBinaryCacheKey(StringRef path, ModuleDependencyInfo &depInfo) {
+    auto &CASFS = scanner.getSharedCachingFS();
+    auto &CAS = scanner.getCAS();
     // For binary module, we need to make sure the lookup key is setup here in
     // action cache. We just use the CASID of the binary module itself as key.
     auto Ref = CASFS.getObjectRefForFileContent(path);
-    if (!Ref)
-      return llvm::errorCodeToError(Ref.getError());
+    if (!Ref) {
+      instance.getDiags().diagnose(SourceLoc(), diag::error_cas_file_ref, path);
+      return true;
+    }
     assert(*Ref && "Binary module should be loaded into CASFS already");
     depInfo.updateModuleCacheKey(CAS.getID(**Ref).toString());
 
     swift::cas::CompileJobCacheResult::Builder Builder;
     Builder.addOutput(file_types::ID::TY_SwiftModuleFile, **Ref);
     auto Result = Builder.build(CAS);
-    if (!Result)
-      return Result.takeError();
-    if (auto E =
-            instance.getActionCache().put(CAS.getID(**Ref), CAS.getID(*Result)))
-      return E;
-    return llvm::Error::success();
+    if (!Result) {
+      instance.getDiags().diagnose(SourceLoc(), diag::error_cas,
+                                   "adding binary module dependencies",
+                                   toString(Result.takeError()));
+      return true;
+    }
+    if (auto E = instance.getActionCache().put(CAS.getID(**Ref),
+                                               CAS.getID(*Result))) {
+      instance.getDiags().diagnose(
+          SourceLoc(), diag::error_cas,
+          "adding binary module dependencies cache entry",
+          toString(std::move(E)));
+      return true;
+    }
+    return false;
+  }
+
+  bool diagnoseCASFSCreationError(llvm::Error err) {
+    if (!err)
+      return false;
+
+    instance.getDiags().diagnose(SourceLoc(), diag::error_cas_fs_creation,
+                                 toString(std::move(err)));
+    return true;
   }
 
   void addDeterministicCheckFlags(std::vector<std::string> &cmd) {
@@ -596,29 +595,76 @@ class ExplicitModuleDependencyResolver {
       cmd.push_back("-cache-disable-replay");
   }
 
+  bool addIncludeTree(StringRef includeTree) {
+    auto &db = scanner.getCAS();
+    auto casID = db.parseID(includeTree);
+    if (!casID) {
+      instance.getDiags().diagnose(SourceLoc(), diag::error_invalid_cas_id,
+                                   includeTree, toString(casID.takeError()));
+      return true;
+    }
+    auto ref = db.getReference(*casID);
+    if (!ref) {
+      instance.getDiags().diagnose(SourceLoc(), diag::error_load_input_from_cas,
+                                   includeTree);
+      return true;
+    }
+
+    auto root = clang::cas::IncludeTreeRoot::get(db, *ref);
+    if (!root) {
+      instance.getDiags().diagnose(SourceLoc(), diag::error_cas_malformed_input,
+                                   includeTree, toString(root.takeError()));
+      return true;
+    }
+
+    fileListRefs.push_back(root->getFileListRef());
+    return false;
+  }
+
+  bool computeCASFileSystem(ModuleDependencyInfo &dependencyInfoCopy) {
+    if (fileListRefs.empty())
+      return false;
+
+    auto &db = scanner.getCAS();
+    auto casFS =
+        clang::cas::IncludeTree::FileList::create(db, {}, fileListRefs);
+    if (!casFS) {
+      instance.getDiags().diagnose(SourceLoc(), diag::error_cas,
+                                   "CAS IncludeTree FileList creation",
+                                   toString(casFS.takeError()));
+      return true;
+    }
+
+    auto casID = casFS->getID().toString();
+    dependencyInfoCopy.updateCASFileSystemRootID(casID);
+    commandline.push_back("-clang-include-tree-filelist");
+    commandline.push_back(casID);
+    return false;
+  }
+
 private:
   const ModuleDependencyID &moduleID;
+  const ModuleDependencyScanner &scanner;
   ModuleDependenciesCache &cache;
   CompilerInstance &instance;
   const ModuleDependencyInfo &resolvingDepInfo;
 
   std::optional<SwiftDependencyTracker> tracker;
-  std::vector<std::string> rootIDs;
-  std::vector<std::string> includeTrees;
-  std::vector<std::string> fileListIDs;
+  std::vector<llvm::cas::ObjectRef> fileListRefs;
   std::vector<std::string> commandline;
   std::vector<std::string> bridgingHeaderBuildCmd;
   llvm::StringMap<MacroPluginDependency> macros;
   llvm::StringSet<> usedVFSOverlayPaths;
 };
 
-static llvm::Error resolveExplicitModuleInputs(
+static bool resolveExplicitModuleInputs(
     const ModuleDependencyID &moduleID,
     const std::set<ModuleDependencyID> &dependencies,
+    const ModuleDependencyScanner &scanner,
     ModuleDependenciesCache &cache, CompilerInstance &instance,
     std::optional<std::set<ModuleDependencyID>> bridgingHeaderDeps,
     std::optional<SwiftDependencyTracker> tracker) {
-  ExplicitModuleDependencyResolver resolver(moduleID, cache, instance,
+  ExplicitModuleDependencyResolver resolver(moduleID, scanner, cache, instance,
                                             std::move(tracker));
   return resolver.resolve(dependencies, bridgingHeaderDeps);
 }
@@ -642,8 +688,9 @@ static bool writeJSONToOutput(DiagnosticEngine &diags,
   });
 }
 
-static void bridgeDependencyIDs(const ArrayRef<ModuleDependencyID> dependencies,
-                                std::vector<std::string> &bridgedDependencyNames) {
+static std::vector<std::string>
+bridgeDependencyIDs(const ModuleDependencyIDCollectionView dependencies) {
+  std::vector<std::string> bridgedDependencyNames;
   for (const auto &dep : dependencies) {
     std::string dependencyKindAndName;
     switch (dep.Kind) {
@@ -654,9 +701,6 @@ static void bridgeDependencyIDs(const ArrayRef<ModuleDependencyID> dependencies,
     case ModuleDependencyKind::SwiftBinary:
       dependencyKindAndName = "swiftBinary";
       break;
-    case ModuleDependencyKind::SwiftPlaceholder:
-      dependencyKindAndName = "swiftPlaceholder";
-      break;
     case ModuleDependencyKind::Clang:
       dependencyKindAndName = "clang";
       break;
@@ -667,6 +711,7 @@ static void bridgeDependencyIDs(const ArrayRef<ModuleDependencyID> dependencies,
     dependencyKindAndName += dep.ModuleName;
     bridgedDependencyNames.push_back(dependencyKindAndName);
   }
+  return bridgedDependencyNames;
 }
 
 static swiftscan_macro_dependency_set_t *createMacroDependencySet(
@@ -680,21 +725,22 @@ static swiftscan_macro_dependency_set_t *createMacroDependencySet(
   unsigned SI = 0;
   for (auto &entry : macroDeps) {
     set->macro_dependencies[SI] = new swiftscan_macro_dependency_s;
-    set->macro_dependencies[SI]->moduleName = create_clone(entry.first.c_str());
-    set->macro_dependencies[SI]->libraryPath =
+    set->macro_dependencies[SI]->module_name =
+        create_clone(entry.first.c_str());
+    set->macro_dependencies[SI]->library_path =
         create_clone(entry.second.LibraryPath.c_str());
-    set->macro_dependencies[SI]->executablePath =
+    set->macro_dependencies[SI]->executable_path =
         create_clone(entry.second.ExecutablePath.c_str());
-    ++ SI;
+    ++SI;
   }
   return set;
 }
 
-static swiftscan_dependency_graph_t
-generateFullDependencyGraph(const CompilerInstance &instance,
-                            const DependencyScanDiagnosticCollector *diagnosticCollector,
-                            const ModuleDependenciesCache &cache,
-                            const ArrayRef<ModuleDependencyID> allModules) {
+static swiftscan_dependency_graph_t generateFullDependencyGraph(
+    const CompilerInstance &instance,
+    const DepScanInMemoryDiagnosticCollector *diagnosticCollector,
+    const ModuleDependenciesCache &cache,
+    const ArrayRef<ModuleDependencyID> allModules) {
   if (allModules.empty()) {
     return nullptr;
   }
@@ -709,7 +755,6 @@ generateFullDependencyGraph(const CompilerInstance &instance,
     const auto &moduleID = allModules[i];
     auto &moduleDependencyInfo = cache.findKnownDependency(moduleID);
     // Collect all the required pieces to build a ModuleInfo
-    auto swiftPlaceholderDeps = moduleDependencyInfo.getAsPlaceholderDependencyModule();
     auto swiftTextualDeps = moduleDependencyInfo.getAsSwiftInterfaceModule();
     auto swiftSourceDeps = moduleDependencyInfo.getAsSwiftSourceModule();
     auto swiftBinaryDeps = moduleDependencyInfo.getAsSwiftBinaryModule();
@@ -721,8 +766,6 @@ generateFullDependencyGraph(const CompilerInstance &instance,
     std::string modulePath;
     if (swiftTextualDeps)
       modulePath = swiftTextualDeps->moduleOutputPath;
-    else if (swiftPlaceholderDeps)
-      modulePath = swiftPlaceholderDeps->compiledModulePath;
     else if (swiftBinaryDeps)
       modulePath = swiftBinaryDeps->compiledModulePath;
     else if (clangDeps)
@@ -738,9 +781,9 @@ generateFullDependencyGraph(const CompilerInstance &instance,
       sourceFiles = clangDeps->fileDependencies;
     }
 
-    auto directDependencies = cache.getAllDependencies(moduleID);
     std::vector<std::string> clangHeaderDependencyNames;
-    for (const auto &headerDepID : moduleDependencyInfo.getHeaderClangDependencies())
+    for (const auto &headerDepID :
+         moduleDependencyInfo.getHeaderClangDependencies())
       clangHeaderDependencyNames.push_back(headerDepID.ModuleName);
 
     // Generate a swiftscan_clang_details_t object based on the dependency kind
@@ -758,11 +801,6 @@ generateFullDependencyGraph(const CompilerInstance &instance,
                           .c_str())
                 : create_null();
         details->kind = SWIFTSCAN_DEPENDENCY_INFO_SWIFT_TEXTUAL;
-        // Create an overlay dependencies set according to the output format
-        std::vector<std::string> bridgedOverlayDependencyNames;
-        bridgeDependencyIDs(swiftTextualDeps->swiftOverlayDependencies,
-                            bridgedOverlayDependencyNames);
-
         details->swift_textual_details = {
             moduleInterfacePath,
             create_set(swiftTextualDeps->compiledModuleCandidates),
@@ -770,7 +808,9 @@ generateFullDependencyGraph(const CompilerInstance &instance,
             create_set(
                 swiftTextualDeps->textualModuleDetails.bridgingSourceFiles),
             create_set(clangHeaderDependencyNames),
-            create_set(bridgedOverlayDependencyNames),
+            create_set(bridgeDependencyIDs(
+                cache.getSwiftOverlayDependencies(moduleID))),
+            /*sourceImportedDependencies*/ create_set({}),
             create_set(swiftTextualDeps->textualModuleDetails.buildCommandLine),
             /*bridgingHeaderBuildCommand*/ create_set({}),
             create_clone(swiftTextualDeps->contextHash.c_str()),
@@ -788,22 +828,23 @@ generateFullDependencyGraph(const CompilerInstance &instance,
       } else if (swiftSourceDeps) {
         swiftscan_string_ref_t moduleInterfacePath = create_null();
         swiftscan_string_ref_t bridgingHeaderPath =
-          swiftSourceDeps->textualModuleDetails.bridgingHeaderFile.has_value()
+            swiftSourceDeps->textualModuleDetails.bridgingHeaderFile.has_value()
                 ? create_clone(
-                           swiftSourceDeps->textualModuleDetails.bridgingHeaderFile.value().c_str())
+                      swiftSourceDeps->textualModuleDetails.bridgingHeaderFile
+                          .value()
+                          .c_str())
                 : create_null();
         details->kind = SWIFTSCAN_DEPENDENCY_INFO_SWIFT_TEXTUAL;
-        // Create an overlay dependencies set according to the output format
-        std::vector<std::string> bridgedOverlayDependencyNames;
-        bridgeDependencyIDs(swiftSourceDeps->swiftOverlayDependencies,
-                            bridgedOverlayDependencyNames);
 
         details->swift_textual_details = {
             moduleInterfacePath, create_empty_set(), bridgingHeaderPath,
             create_set(
                 swiftSourceDeps->textualModuleDetails.bridgingSourceFiles),
             create_set(clangHeaderDependencyNames),
-            create_set(bridgedOverlayDependencyNames),
+            create_set(bridgeDependencyIDs(
+                cache.getSwiftOverlayDependencies(moduleID))),
+            create_set(bridgeDependencyIDs(
+                cache.getDirectImportedDependencies(moduleID))),
             create_set(swiftSourceDeps->textualModuleDetails.buildCommandLine),
             create_set(swiftSourceDeps->bridgingHeaderBuildCommandLine),
             /*contextHash*/
@@ -823,23 +864,14 @@ generateFullDependencyGraph(const CompilerInstance &instance,
             create_clone(swiftSourceDeps->chainedBridgingHeaderPath.c_str()),
             create_clone(
                 swiftSourceDeps->chainedBridgingHeaderContent.c_str())};
-      } else if (swiftPlaceholderDeps) {
-        details->kind = SWIFTSCAN_DEPENDENCY_INFO_SWIFT_PLACEHOLDER;
-        details->swift_placeholder_details = {
-            create_clone(swiftPlaceholderDeps->compiledModulePath.c_str()),
-            create_clone(swiftPlaceholderDeps->moduleDocPath.c_str()),
-            create_clone(swiftPlaceholderDeps->sourceInfoPath.c_str())};
       } else if (swiftBinaryDeps) {
         details->kind = SWIFTSCAN_DEPENDENCY_INFO_SWIFT_BINARY;
-        // Create an overlay dependencies set according to the output format
-        std::vector<std::string> bridgedOverlayDependencyNames;
-        bridgeDependencyIDs(swiftBinaryDeps->swiftOverlayDependencies,
-                            bridgedOverlayDependencyNames);
         details->swift_binary_details = {
             create_clone(swiftBinaryDeps->compiledModulePath.c_str()),
             create_clone(swiftBinaryDeps->moduleDocPath.c_str()),
             create_clone(swiftBinaryDeps->sourceInfoPath.c_str()),
-            create_set(bridgedOverlayDependencyNames),
+            create_set(bridgeDependencyIDs(
+                cache.getSwiftOverlayDependencies(moduleID))),
             create_clone(swiftBinaryDeps->headerImport.c_str()),
             create_set(clangHeaderDependencyNames),
             create_set(swiftBinaryDeps->headerSourceFiles),
@@ -870,16 +902,11 @@ generateFullDependencyGraph(const CompilerInstance &instance,
     moduleInfo->module_name = ttt;
     moduleInfo->module_path = create_clone(modulePath.c_str());
     moduleInfo->source_files = create_set(sourceFiles);
-
-    // Create a direct dependencies set according to the output format
-    std::vector<std::string> bridgedDependencyNames;
-    bridgeDependencyIDs(directDependencies.getArrayRef(),
-                        bridgedDependencyNames);
-    moduleInfo->direct_dependencies = create_set(bridgedDependencyNames);
+    moduleInfo->direct_dependencies = create_set(bridgeDependencyIDs(cache.getAllDependencies(moduleID)));
     moduleInfo->details = getModuleDetails();
 
     // Create a link libraries set for this module
-    auto &linkLibraries = moduleDependencyInfo.getLinkLibraries();
+    auto linkLibraries = moduleDependencyInfo.getLinkLibraries();
     swiftscan_link_library_set_t *linkLibrarySet =
         new swiftscan_link_library_set_t;
     linkLibrarySet->count = linkLibraries.size();
@@ -895,15 +922,54 @@ generateFullDependencyGraph(const CompilerInstance &instance,
       linkLibrarySet->link_libraries[i] = llInfo;
     }
     moduleInfo->link_libraries = linkLibrarySet;
+
+    auto createImportSetInfo = [&](ArrayRef<ScannerImportStatementInfo> imports)
+        -> swiftscan_import_info_set_t * {
+      swiftscan_import_info_set_t *importInfoSet =
+          new swiftscan_import_info_set_t;
+      importInfoSet->count = imports.size();
+      importInfoSet->imports =
+          new swiftscan_import_info_t[importInfoSet->count];
+      for (size_t i = 0; i < imports.size(); ++i) {
+        const auto &ii = imports[i];
+        swiftscan_import_info_s *iInfo = new swiftscan_import_info_s;
+        iInfo->import_identifier = create_clone(ii.importIdentifier.c_str());
+        iInfo->access_level =
+            static_cast<swiftscan_access_level_t>(ii.accessLevel);
+
+        const auto &sourceLocations = ii.importLocations;
+        swiftscan_source_location_set_t *sourceLocSet =
+            new swiftscan_source_location_set_t;
+        sourceLocSet->count = sourceLocations.size();
+        sourceLocSet->source_locations =
+            new swiftscan_source_location_t[sourceLocSet->count];
+        for (size_t j = 0; j < sourceLocations.size(); ++j) {
+          const auto &sl = sourceLocations[j];
+          swiftscan_source_location_s *slInfo = new swiftscan_source_location_s;
+          slInfo->buffer_identifier = create_clone(sl.bufferIdentifier.c_str());
+          slInfo->line_number = sl.lineNumber;
+          slInfo->column_number = sl.columnNumber;
+          sourceLocSet->source_locations[j] = slInfo;
+        }
+        iInfo->source_locations = sourceLocSet;
+        importInfoSet->imports[i] = iInfo;
+      }
+      return importInfoSet;
+    };
+    // Create source import infos set for this module
+    moduleInfo->imports =
+        createImportSetInfo(moduleDependencyInfo.getModuleImports());
+    moduleInfo->optional_imports =
+        createImportSetInfo(moduleDependencyInfo.getOptionalModuleImports());
   }
 
   swiftscan_dependency_graph_t result = new swiftscan_dependency_graph_s;
   result->main_module_name = create_clone(mainModuleName.c_str());
   result->dependencies = dependencySet;
-  result->diagnostics =
-              diagnosticCollector
-              ? mapCollectedDiagnosticsForOutput(diagnosticCollector)
-              : nullptr;
+  result->diagnostics = diagnosticCollector
+                            ? mapCollectedDiagnosticsForOutput(
+                                  diagnosticCollector->getDiagnostics())
+                            : nullptr;
   return result;
 }
 
@@ -1029,7 +1095,7 @@ findClangDepPath(const ModuleDependencyID &from, const ModuleDependencyID &to,
     }
 
     // Otherwise, visit each child node.
-    for (const auto &succID : cache.getAllDependencies(moduleID)) {
+    for (const auto &succID : cache.getImportedClangDependencies(moduleID)) {
       stack.push(succID);
       visit(succID);
       stack.pop();
@@ -1083,7 +1149,7 @@ static bool diagnoseCycle(const CompilerInstance &instance,
   };
 
   auto emitCycleDiagnostic = [&](const ModuleDependencyID &sourceId,
-				 const ModuleDependencyID &sinkId) {
+                                 const ModuleDependencyID &sinkId) {
     auto startIt = std::find(openSet.begin(), openSet.end(), sourceId);
     assert(startIt != openSet.end());
     std::vector<ModuleDependencyID> cycleNodes(startIt, openSet.end());
@@ -1117,6 +1183,24 @@ static bool diagnoseCycle(const CompilerInstance &instance,
             thisID.ModuleName, nextID.ModuleName, noteBuffer.str());
       }
     }
+
+    // Check if this is a case of a source target shadowing
+    // a module with the same name
+    if (sourceId.Kind == swift::ModuleDependencyKind::SwiftSource) {
+      auto sinkModuleDefiningPath =
+          cache.findKnownDependency(sinkId).getModuleDefiningPath();
+      auto SDKPath =
+          instance.getInvocation().getSearchPathOptions().getSDKPath();
+      auto sinkIsInSDK =
+          !SDKPath.empty() &&
+          hasPrefix(llvm::sys::path::begin(sinkModuleDefiningPath),
+                    llvm::sys::path::end(sinkModuleDefiningPath),
+                    llvm::sys::path::begin(SDKPath),
+                    llvm::sys::path::end(SDKPath));
+      instance.getASTContext().Diags.diagnose(
+          SourceLoc(), diag::scanner_cycle_source_target_shadow_module,
+          sourceId.ModuleName, sinkModuleDefiningPath, sinkIsInSDK);
+    }
   };
 
   // Start from the main module and check direct and overlay dependencies
@@ -1124,8 +1208,16 @@ static bool diagnoseCycle(const CompilerInstance &instance,
   while (!openSet.empty()) {
     auto lastOpen = openSet.back();
     auto beforeSize = openSet.size();
+
+#ifndef NDEBUG
+    if (!cache.findDependency(lastOpen)) {
+      llvm::dbgs() << "Missing Dependency Info during cycle diagnosis\n";
+      llvm::dbgs() << "mainID: " << mainId.ModuleName << "\n";
+      llvm::dbgs() << "lastOpen: " << lastOpen.ModuleName << "\n";
+    }
+#endif
     assert(cache.findDependency(lastOpen).has_value() &&
-           "Missing dependency info during cycle diagnosis.");
+           "Missing dependency info during cycle diagnosis");
     for (const auto &depId : cache.getAllDependencies(lastOpen)) {
       if (closeSet.count(depId))
         continue;
@@ -1155,102 +1247,15 @@ static bool diagnoseCycle(const CompilerInstance &instance,
   closeSet.clear();
   return false;
 }
-} // namespace
-
-bool swift::dependencies::scanDependencies(CompilerInstance &CI) {
-  ASTContext &ctx = CI.getASTContext();
-  std::string depGraphOutputPath =
-    CI.getInvocation().getFrontendOptions().InputsAndOutputs.getSingleOutputFilename();
-  // `-scan-dependencies` invocations use a single new instance
-  // of a module cache
-  SwiftDependencyScanningService *service =
-      ctx.Allocate<SwiftDependencyScanningService>();
-  ModuleDependenciesCache cache(
-      *service, CI.getMainModule()->getNameStr().str(),
-      CI.getInvocation().getFrontendOptions().ExplicitModulesOutputPath,
-      CI.getInvocation().getFrontendOptions().ExplicitSDKModulesOutputPath,
-      CI.getInvocation().getModuleScanningHash());
-
-  if (service->setupCachingDependencyScanningService(CI))
-    return true;
-
-  // Execute scan
-  llvm::ErrorOr<swiftscan_dependency_graph_t> dependenciesOrErr =
-      performModuleScan(CI, nullptr, cache);
-
-  if (dependenciesOrErr.getError())
-    return true;
-  auto dependencies = std::move(*dependenciesOrErr);
-
-  if (writeJSONToOutput(ctx.Diags, CI.getOutputBackend(), depGraphOutputPath,
-                        dependencies))
-    return true;
-
-  // This process succeeds regardless of whether any errors occurred.
-  // FIXME: We shouldn't need this, but it's masking bugs in our scanning
-  // logic where we don't create a fresh context when scanning Swift interfaces
-  // that includes their own command-line flags.
-  ctx.Diags.resetHadAnyError();
-  return false;
-}
-
-bool swift::dependencies::prescanDependencies(CompilerInstance &instance) {
-  ASTContext &Context = instance.getASTContext();
-  const FrontendOptions &opts = instance.getInvocation().getFrontendOptions();
-  std::string path = opts.InputsAndOutputs.getSingleOutputFilename();
-  // `-scan-dependencies` invocations use a single new instance
-  // of a module cache
-  SwiftDependencyScanningService *singleUseService = Context.Allocate<SwiftDependencyScanningService>();
-  ModuleDependenciesCache cache(
-      *singleUseService, instance.getMainModule()->getNameStr().str(),
-      instance.getInvocation().getFrontendOptions().ExplicitModulesOutputPath,
-      instance.getInvocation().getFrontendOptions().ExplicitSDKModulesOutputPath,
-      instance.getInvocation().getModuleScanningHash());
-
-  // Execute import prescan, and write JSON output to the output stream
-  auto importSetOrErr = performModulePrescan(instance, nullptr, cache);
-  if (importSetOrErr.getError())
-    return true;
-  auto importSet = std::move(*importSetOrErr);
-
-  // Serialize and output main module dependencies only and exit.
-  if (writePrescanJSONToOutput(Context.Diags, instance.getOutputBackend(), path,
-                               importSet))
-    return true;
-
-  // This process succeeds regardless of whether any errors occurred.
-  // FIXME: We shouldn't need this, but it's masking bugs in our scanning
-  // logic where we don't create a fresh context when scanning Swift interfaces
-  // that includes their own command-line flags.
-  Context.Diags.resetHadAnyError();
-  return false;
-}
-
-std::string
-swift::dependencies::createEncodedModuleKindAndName(ModuleDependencyID id) {
-  switch (id.Kind) {
-  case ModuleDependencyKind::SwiftInterface:
-  case ModuleDependencyKind::SwiftSource:
-    return "swiftTextual:" + id.ModuleName;
-  case ModuleDependencyKind::SwiftBinary:
-    return "swiftBinary:" + id.ModuleName;
-  case ModuleDependencyKind::SwiftPlaceholder:
-    return "swiftPlaceholder:" + id.ModuleName;
-  case ModuleDependencyKind::Clang:
-    return "clang:" + id.ModuleName;
-  default:
-    llvm_unreachable("Unhandled dependency kind.");
-  }
-}
 
-static void resolveDependencyCommandLineArguments(
-    CompilerInstance &instance, ModuleDependenciesCache &cache,
+static bool resolveDependencyCommandLineArguments(
+    ModuleDependencyScanner &scanner, CompilerInstance &instance,
+    ModuleDependenciesCache &cache,
     const std::vector<ModuleDependencyID> &topoSortedModuleList) {
   auto moduleTransitiveClosures =
       computeTransitiveClosureOfExplicitDependencies(topoSortedModuleList,
                                                      cache);
-  auto tracker = cache.getScanService().createSwiftDependencyTracker(
-      instance.getInvocation());
+  auto tracker = scanner.createSwiftDependencyTracker(instance.getInvocation());
   for (const auto &modID : llvm::reverse(topoSortedModuleList)) {
     auto dependencyClosure = moduleTransitiveClosures[modID];
     // For main module or binary modules, no command-line to resolve.
@@ -1262,12 +1267,12 @@ static void resolveDependencyCommandLineArguments(
       bridgingHeaderDeps = computeBridgingHeaderTransitiveDependencies(
           deps, moduleTransitiveClosures, cache);
 
-    if (auto E =
-            resolveExplicitModuleInputs(modID, dependencyClosure, cache,
-                                        instance, bridgingHeaderDeps, tracker))
-      instance.getDiags().diagnose(SourceLoc(), diag::error_cas,
-                                   toString(std::move(E)));
+    if (resolveExplicitModuleInputs(modID, dependencyClosure, scanner, cache,
+                                    instance, bridgingHeaderDeps, tracker))
+      return true;
   }
+
+  return false;
 }
 
 static void
@@ -1323,7 +1328,8 @@ static void resolveImplicitLinkLibraries(const CompilerInstance &instance,
 
   if (langOpts.EnableCXXInterop) {
     auto OptionalCxxDep = cache.findDependency(CXX_MODULE_NAME);
-    auto OptionalCxxStdLibDep = cache.findDependency("CxxStdlib");
+    auto OptionalCxxStdLibDep =
+        cache.findDependency(instance.getASTContext().Id_CxxStdlib.str());
     bool hasStaticCxx =
         OptionalCxxDep.has_value() && OptionalCxxDep.value()->isStaticLibrary();
     bool hasStaticCxxStdlib = OptionalCxxStdLibDep.has_value() &&
@@ -1340,13 +1346,13 @@ static void resolveImplicitLinkLibraries(const CompilerInstance &instance,
   cache.updateDependency(mainModuleID, mainModuleDepInfo);
 }
 
-llvm::ErrorOr<swiftscan_dependency_graph_t>
-swift::dependencies::performModuleScan(
-    CompilerInstance &instance,
-    DependencyScanDiagnosticCollector *diagnosticCollector,
-    ModuleDependenciesCache &cache) {
-  const ASTContext &ctx = instance.getASTContext();
-  const FrontendOptions &opts = instance.getInvocation().getFrontendOptions();
+static llvm::ErrorOr<swiftscan_dependency_graph_t>
+performModuleScanImpl(
+    SwiftDependencyScanningService &service, CompilerInstance *instance,
+    ModuleDependenciesCache &cache,
+    DepScanInMemoryDiagnosticCollector *diagnosticCollector) {
+  const ASTContext &ctx = instance->getASTContext();
+  const FrontendOptions &opts = instance->getInvocation().getFrontendOptions();
   // Load the dependency cache if -reuse-dependency-scan-cache
   // is specified
   if (opts.ReuseDependencyScannerCache) {
@@ -1364,73 +1370,76 @@ swift::dependencies::performModuleScan(
 
     if (!loadFailure && opts.ValidatePriorDependencyScannerCache) {
       auto mainModuleID =
-          ModuleDependencyID{instance.getMainModule()->getNameStr().str(),
+          ModuleDependencyID{instance->getMainModule()->getNameStr().str(),
                              ModuleDependencyKind::SwiftSource};
       incremental::validateInterModuleDependenciesCache(
-          mainModuleID, cache, serializedCacheTimeStamp,
-          *instance.getSourceMgr().getFileSystem(), ctx.Diags,
-          opts.EmitDependencyScannerCacheRemarks);
+          mainModuleID, cache, instance->getSharedCASInstance(),
+          serializedCacheTimeStamp, *instance->getSourceMgr().getFileSystem(),
+          ctx.Diags, opts.EmitDependencyScannerCacheRemarks);
     }
   }
 
   auto scanner = ModuleDependencyScanner(
-      cache.getScanService(), instance.getInvocation(),
-      instance.getSILOptions(), instance.getASTContext(),
-      *instance.getDependencyTracker(), instance.getDiags(),
-      instance.getInvocation().getFrontendOptions().ParallelDependencyScan);
+      service, instance->getInvocation(), instance->getSILOptions(),
+      instance->getASTContext(), *instance->getDependencyTracker(),
+      instance->getSharedCASInstance(), instance->getSharedCacheInstance(),
+      instance->getDiags(),
+      instance->getInvocation().getFrontendOptions().ParallelDependencyScan);
 
   // Identify imports of the main module and add an entry for it
   // to the dependency graph.
-  auto mainModuleName = instance.getMainModule()->getNameStr();
+  auto mainModuleName = instance->getMainModule()->getNameStr();
   auto mainModuleID = ModuleDependencyID{mainModuleName.str(),
                                          ModuleDependencyKind::SwiftSource};
   if (!cache.hasDependency(mainModuleID))
-    cache.recordDependency(mainModuleName,
-                           *scanner.getMainModuleDependencyInfo(instance.getMainModule()));
+    cache.recordDependency(mainModuleName, *scanner.getMainModuleDependencyInfo(
+                                               instance->getMainModule()));
 
   // Perform the full module scan starting at the main module.
   auto allModules = scanner.performDependencyScan(mainModuleID, cache);
-  if (diagnoseCycle(instance, cache, mainModuleID))
+  if (diagnoseCycle(*instance, cache, mainModuleID))
     return std::make_error_code(std::errc::not_supported);
 
   auto topologicallySortedModuleList =
       computeTopologicalSortOfExplicitDependencies(allModules, cache);
 
-  resolveDependencyCommandLineArguments(instance, cache,
+  resolveDependencyCommandLineArguments(scanner, *instance, cache,
                                         topologicallySortedModuleList);
-  resolveImplicitLinkLibraries(instance, cache);
-  updateDependencyTracker(instance, cache, allModules);
+  resolveImplicitLinkLibraries(*instance, cache);
+  updateDependencyTracker(*instance, cache, allModules);
 
   if (ctx.Stats)
-    ctx.Stats->getFrontendCounters().NumDepScanFilesystemLookups = scanner.getNumLookups();
+    ctx.Stats->getFrontendCounters().NumDepScanFilesystemLookups =
+        scanner.getNumLookups();
 
   // Serialize the dependency cache if -serialize-dependency-scan-cache
   // is specified
   if (opts.SerializeDependencyScannerCache) {
     auto savePath = opts.SerializedDependencyScannerCachePath;
     module_dependency_cache_serialization::writeInterModuleDependenciesCache(
-        ctx.Diags, instance.getOutputBackend(), savePath, cache);
+        ctx.Diags, instance->getOutputBackend(), savePath, cache);
     if (opts.EmitDependencyScannerCacheRemarks)
       ctx.Diags.diagnose(SourceLoc(), diag::remark_save_cache, savePath);
   }
 
-  return generateFullDependencyGraph(instance, diagnosticCollector, cache,
-                                     topologicallySortedModuleList);
+  return generateFullDependencyGraph(*instance, diagnosticCollector,
+                                     cache, topologicallySortedModuleList);
 }
 
-llvm::ErrorOr<swiftscan_import_set_t>
-swift::dependencies::performModulePrescan(CompilerInstance &instance,
-                                          DependencyScanDiagnosticCollector *diagnosticCollector,
-                                          ModuleDependenciesCache &cache) {
+static llvm::ErrorOr<swiftscan_import_set_t> performModulePrescanImpl(
+    SwiftDependencyScanningService &service, CompilerInstance *instance,
+    ModuleDependenciesCache &cache,
+    DepScanInMemoryDiagnosticCollector *diagnosticCollector) {
   // Setup the scanner
   auto scanner = ModuleDependencyScanner(
-      cache.getScanService(), instance.getInvocation(),
-      instance.getSILOptions(), instance.getASTContext(),
-      *instance.getDependencyTracker(), instance.getDiags(),
-      instance.getInvocation().getFrontendOptions().ParallelDependencyScan);
+      service, instance->getInvocation(), instance->getSILOptions(),
+      instance->getASTContext(), *instance->getDependencyTracker(),
+      instance->getSharedCASInstance(), instance->getSharedCacheInstance(),
+      instance->getDiags(),
+      instance->getInvocation().getFrontendOptions().ParallelDependencyScan);
   // Execute import prescan, and write JSON output to the output stream
   auto mainDependencies =
-      scanner.getMainModuleDependencyInfo(instance.getMainModule());
+      scanner.getMainModuleDependencyInfo(instance->getMainModule());
   if (!mainDependencies)
     return mainDependencies.getError();
   auto *importSet = new swiftscan_import_set_s;
@@ -1443,24 +1452,125 @@ swift::dependencies::performModulePrescan(CompilerInstance &instance,
                     return importInfo.importIdentifier;
                   });
   importSet->imports = create_set(importIdentifiers);
-  importSet->diagnostics =
-      diagnosticCollector
-          ? mapCollectedDiagnosticsForOutput(diagnosticCollector)
-          : nullptr;
-  importSet->diagnostics =
-      diagnosticCollector
-          ? mapCollectedDiagnosticsForOutput(diagnosticCollector)
-          : nullptr;
+  importSet->diagnostics = diagnosticCollector
+                               ? mapCollectedDiagnosticsForOutput(
+                                     diagnosticCollector->getDiagnostics())
+                               : nullptr;
+  importSet->diagnostics = diagnosticCollector
+                               ? mapCollectedDiagnosticsForOutput(
+                                     diagnosticCollector->getDiagnostics())
+                               : nullptr;
   return importSet;
 }
+} // namespace
+
+bool swift::dependencies::scanDependencies(CompilerInstance &CI) {
+  ASTContext &ctx = CI.getASTContext();
+  std::string depGraphOutputPath =
+      CI.getInvocation()
+          .getFrontendOptions()
+          .InputsAndOutputs.getSingleOutputFilename();
+  // `-scan-dependencies` invocations use a single new instance
+  // of a module cache
+  SwiftDependencyScanningService *service =
+      ctx.Allocate<SwiftDependencyScanningService>();
+  ModuleDependenciesCache cache(CI.getMainModule()->getNameStr().str(),
+                                CI.getInvocation().getModuleScanningHash());
+
+  if (service->setupCachingDependencyScanningService(CI))
+    return true;
+
+  // Execute scan
+  llvm::ErrorOr<swiftscan_dependency_graph_t> dependenciesOrErr =
+      performModuleScanImpl(*service, &CI, cache, nullptr);
+
+  if (dependenciesOrErr.getError())
+    return true;
+  auto dependencies = std::move(*dependenciesOrErr);
+
+  if (writeJSONToOutput(ctx.Diags, CI.getOutputBackend(), depGraphOutputPath,
+                        dependencies))
+    return true;
+
+  // This process succeeds regardless of whether any errors occurred.
+  // FIXME: We shouldn't need this, but it's masking bugs in our scanning
+  // logic where we don't create a fresh context when scanning Swift interfaces
+  // that includes their own command-line flags.
+  ctx.Diags.resetHadAnyError();
+  return false;
+}
+
+bool swift::dependencies::prescanDependencies(CompilerInstance &instance) {
+  ASTContext &Context = instance.getASTContext();
+  const FrontendOptions &opts = instance.getInvocation().getFrontendOptions();
+  std::string path = opts.InputsAndOutputs.getSingleOutputFilename();
+  // `-scan-dependencies` invocations use a single new instance
+  // of a module cache
+  SwiftDependencyScanningService *singleUseService =
+      Context.Allocate<SwiftDependencyScanningService>();
+  ModuleDependenciesCache cache(
+      instance.getMainModule()->getNameStr().str(),
+      instance.getInvocation().getModuleScanningHash());
+
+  // Execute import prescan, and write JSON output to the output stream
+  auto importSetOrErr =
+      performModulePrescanImpl(*singleUseService, &instance, cache, nullptr);
+  if (importSetOrErr.getError())
+    return true;
+  auto importSet = std::move(*importSetOrErr);
+
+  // Serialize and output main module dependencies only and exit.
+  if (writePrescanJSONToOutput(Context.Diags, instance.getOutputBackend(), path,
+                               importSet))
+    return true;
+
+  // This process succeeds regardless of whether any errors occurred.
+  // FIXME: We shouldn't need this, but it's masking bugs in our scanning
+  // logic where we don't create a fresh context when scanning Swift interfaces
+  // that includes their own command-line flags.
+  Context.Diags.resetHadAnyError();
+  return false;
+}
+
+std::string
+swift::dependencies::createEncodedModuleKindAndName(ModuleDependencyID id) {
+  switch (id.Kind) {
+  case ModuleDependencyKind::SwiftInterface:
+  case ModuleDependencyKind::SwiftSource:
+    return "swiftTextual:" + id.ModuleName;
+  case ModuleDependencyKind::SwiftBinary:
+    return "swiftBinary:" + id.ModuleName;
+  case ModuleDependencyKind::Clang:
+    return "clang:" + id.ModuleName;
+  default:
+    llvm_unreachable("Unhandled dependency kind.");
+  }
+}
+
+llvm::ErrorOr<swiftscan_dependency_graph_t>
+swift::dependencies::performModuleScan(SwiftDependencyScanningService &service,
+                                       ModuleDependenciesCache &cache,
+                                       ScanQueryContext &queryContext) {
+  return performModuleScanImpl(service, queryContext.ScanInstance.get(), cache,
+                               queryContext.InMemoryDiagnosticCollector.get());
+}
+
+llvm::ErrorOr<swiftscan_import_set_t> swift::dependencies::performModulePrescan(
+    SwiftDependencyScanningService &service, ModuleDependenciesCache &cache,
+    ScanQueryContext &queryContext) {
+  return performModulePrescanImpl(
+      service, queryContext.ScanInstance.get(), cache,
+      queryContext.InMemoryDiagnosticCollector.get());
+}
 
 void swift::dependencies::incremental::validateInterModuleDependenciesCache(
     const ModuleDependencyID &rootModuleID, ModuleDependenciesCache &cache,
+    std::shared_ptr<llvm::cas::ObjectStore> cas,
     const llvm::sys::TimePoint<> &cacheTimeStamp, llvm::vfs::FileSystem &fs,
     DiagnosticEngine &diags, bool emitRemarks) {
   ModuleDependencyIDSet visited;
   ModuleDependencyIDSet modulesRequiringRescan;
-  outOfDateModuleScan(rootModuleID, cache, cacheTimeStamp, fs, diags,
+  outOfDateModuleScan(rootModuleID, cache, cas, cacheTimeStamp, fs, diags,
                       emitRemarks, visited, modulesRequiringRescan);
   for (const auto &outOfDateModID : modulesRequiringRescan)
     cache.removeDependency(outOfDateModID);
@@ -1471,6 +1581,7 @@ void swift::dependencies::incremental::validateInterModuleDependenciesCache(
 
 void swift::dependencies::incremental::outOfDateModuleScan(
     const ModuleDependencyID &moduleID, const ModuleDependenciesCache &cache,
+    std::shared_ptr<llvm::cas::ObjectStore> cas,
     const llvm::sys::TimePoint<> &cacheTimeStamp, llvm::vfs::FileSystem &fs,
     DiagnosticEngine &diags, bool emitRemarks, ModuleDependencyIDSet &visited,
     ModuleDependencyIDSet &modulesRequiringRescan) {
@@ -1479,8 +1590,8 @@ void swift::dependencies::incremental::outOfDateModuleScan(
   for (const auto &depID : cache.getAllDependencies(moduleID)) {
     // If we have not already visited this module, recurse.
     if (visited.find(depID) == visited.end())
-      outOfDateModuleScan(depID, cache, cacheTimeStamp, fs, diags, emitRemarks,
-                          visited, modulesRequiringRescan);
+      outOfDateModuleScan(depID, cache, cas, cacheTimeStamp, fs, diags,
+                          emitRemarks, visited, modulesRequiringRescan);
 
     // Even if we're not revisiting a dependency, we must check if it's
     // already known to be out of date.
@@ -1493,8 +1604,8 @@ void swift::dependencies::incremental::outOfDateModuleScan(
       diags.diagnose(SourceLoc(), diag::remark_scanner_invalidate_upstream,
                      moduleID.ModuleName);
     modulesRequiringRescan.insert(moduleID);
-  } else if (!verifyModuleDependencyUpToDate(moduleID, cache, cacheTimeStamp,
-                                             fs, diags, emitRemarks))
+  } else if (!verifyModuleDependencyUpToDate(
+                 moduleID, cache, cas, cacheTimeStamp, fs, diags, emitRemarks))
     modulesRequiringRescan.insert(moduleID);
 
   visited.insert(moduleID);
@@ -1502,6 +1613,7 @@ void swift::dependencies::incremental::outOfDateModuleScan(
 
 bool swift::dependencies::incremental::verifyModuleDependencyUpToDate(
     const ModuleDependencyID &moduleID, const ModuleDependenciesCache &cache,
+    std::shared_ptr<llvm::cas::ObjectStore> cas,
     const llvm::sys::TimePoint<> &cacheTimeStamp, llvm::vfs::FileSystem &fs,
     DiagnosticEngine &diags, bool emitRemarks) {
   const auto &moduleInfo = cache.findKnownDependency(moduleID);
@@ -1521,9 +1633,9 @@ bool swift::dependencies::incremental::verifyModuleDependencyUpToDate(
     return true;
   };
 
-  auto verifyCASID = [&cache, &diags, emitRemarks](StringRef moduleName,
-                                                   const std::string &casID) {
-    if (!cache.getScanService().hasCAS()) {
+  auto verifyCASID = [cas, &diags, emitRemarks](StringRef moduleName,
+                                                     const std::string &casID) {
+    if (!cas) {
       // If the wrong cache is passed.
       if (emitRemarks)
         diags.diagnose(SourceLoc(),
@@ -1531,15 +1643,14 @@ bool swift::dependencies::incremental::verifyModuleDependencyUpToDate(
                        moduleName);
       return false;
     }
-    auto &CAS = cache.getScanService().getCAS();
-    auto ID = CAS.parseID(casID);
+    auto ID = cas->parseID(casID);
     if (!ID) {
       if (emitRemarks)
         diags.diagnose(SourceLoc(), diag::remark_scanner_invalidate_cas_error,
                        moduleName, toString(ID.takeError()));
       return false;
     }
-    if (!CAS.getReference(*ID)) {
+    if (!cas->getReference(*ID)) {
       if (emitRemarks)
         diags.diagnose(SourceLoc(), diag::remark_scanner_invalidate_missing_cas,
                        moduleName, casID);
diff --git a/lib/Driver/Compilation.cpp b/lib/Driver/Compilation.cpp
index a1041a088712b..cd762cd916969 100644
--- a/lib/Driver/Compilation.cpp
+++ b/lib/Driver/Compilation.cpp
@@ -52,12 +52,6 @@
 #include <io.h>
 #endif
 
-#define DEBUG_TYPE "batch-mode"
-
-// Batch-mode has a sub-mode for testing that randomizes batch partitions,
-// by user-provided seed. That is the only thing randomized here.
-#include <random>
-
 using namespace swift;
 using namespace swift::sys;
 using namespace swift::driver;
@@ -111,10 +105,6 @@ Compilation::Compilation(DiagnosticEngine &Diags,
                          std::unique_ptr<DerivedArgList> TranslatedArgs,
                          InputFileList InputsWithTypes,
                          size_t FilelistThreshold,
-                         bool EnableBatchMode,
-                         unsigned BatchSeed,
-                         std::optional<unsigned> BatchCount,
-                         std::optional<unsigned> BatchSizeLimit,
                          bool SaveTemps,
                          bool ShowDriverTimeCompilation,
                          std::unique_ptr<UnifiedStatsReporter> StatsReporter,
@@ -125,10 +115,6 @@ Compilation::Compilation(DiagnosticEngine &Diags,
     RawInputArgs(std::move(InputArgs)),
     TranslatedArgs(std::move(TranslatedArgs)),
     InputFilesWithTypes(std::move(InputsWithTypes)),
-    EnableBatchMode(EnableBatchMode),
-    BatchSeed(BatchSeed),
-    BatchCount(BatchCount),
-    BatchSizeLimit(BatchSizeLimit),
     SaveTemps(SaveTemps),
     ShowDriverTimeCompilation(ShowDriverTimeCompilation),
     Stats(std::move(StatsReporter)),
@@ -140,7 +126,6 @@ static bool writeFilelistIfNecessary(const Job *job, const ArgList &args,
                                      DiagnosticEngine &diags);
 
 using CommandSetVector = llvm::SetVector<const Job*>;
-using BatchPartition = std::vector<std::vector<const Job*>>;
 
 namespace {
 static DetailedTaskDescription
@@ -205,26 +190,9 @@ namespace driver {
     CommandSet ScheduledCommands;
 
     /// A temporary buffer to hold commands that were scheduled but haven't been
-    /// added to the Task Queue yet, because we might try batching them together
-    /// first.
+    /// added to the Task Queue yet
     CommandSetVector PendingExecution;
 
-    /// Set of synthetic BatchJobs that serve to cluster subsets of jobs waiting
-    /// in PendingExecution. Also used to identify (then unpack) BatchJobs back
-    /// to their underlying non-Batch Jobs, when running a callback from
-    /// TaskQueue.
-    CommandSet BatchJobs;
-
-    /// Persistent counter for allocating quasi-PIDs to Jobs combined into
-    /// BatchJobs. Quasi-PIDs are _negative_ PID-like unique keys used to
-    /// masquerade BatchJob constituents as (quasi)processes, when writing
-    /// parseable output to consumers that don't understand the idea of a batch
-    /// job. They are negative in order to avoid possibly colliding with real
-    /// PIDs (which are always positive). We start at -1000 here as a crude but
-    /// harmless hedge against colliding with an errno value that might slip
-    /// into the stream of real PIDs (say, due to a TaskQueue bug).
-    int64_t NextBatchQuasiPID = parseable_output::QUASI_PID_START;
-
     /// All jobs which have finished execution or which have been determined
     /// that they don't need to run.
     CommandSet FinishedCommands;
@@ -289,7 +257,7 @@ namespace driver {
       ScheduledCommands.insert(Cmd);
 
       // Adding to pending means it should be in the next round of additions to
-      // the task queue (either batched or singularly); we remove Jobs from
+      // the task queue; we remove Jobs from
       // PendingExecution once we hand them over to the TaskQueue.
       PendingExecution.insert(Cmd);
     }
@@ -314,8 +282,8 @@ namespace driver {
              "not implemented for compilations with multiple jobs");
       if (Comp.getShowJobLifecycle())
         llvm::outs() << "Added to TaskQueue: " << LogJob(Cmd) << "\n";
-      TQ->addTask(Cmd->getExecutable(), Cmd->getArgumentsForTaskExecution(),
-                  std::nullopt, (void *)Cmd);
+      TQ->addTask(Cmd->getExecutable(), Cmd->getArgumentsForTaskExecution(), {},
+                  (void *)Cmd);
     }
 
     /// When a task finishes, check other Jobs that may be blocked.
@@ -345,10 +313,6 @@ namespace driver {
       }
     }
 
-    bool isBatchJob(const Job *MaybeBatchJob) const {
-      return BatchJobs.count(MaybeBatchJob) != 0;
-    }
-
     /// Callback which will be called immediately after a task has started. This
     /// callback may be used to provide output indicating that the task began.
     void taskBegan(ProcessId Pid, void *Context) {
@@ -390,60 +354,6 @@ namespace driver {
       }
     }
 
-    /// Check to see if a job produced a zero-length serialized diagnostics
-    /// file, which is used to indicate batch-constituents that were batched
-    /// together with a failing constituent but did not, themselves, produce any
-    /// errors.
-    bool jobWasBatchedWithFailingJobs(const Job *J) const {
-      auto DiaPath =
-        J->getOutput().getAnyOutputForType(file_types::TY_SerializedDiagnostics);
-      if (DiaPath.empty())
-        return false;
-      if (!llvm::sys::fs::is_regular_file(DiaPath))
-        return false;
-      uint64_t Size;
-      auto EC = llvm::sys::fs::file_size(DiaPath, Size);
-      if (EC)
-        return false;
-      return Size == 0;
-    }
-
-    /// If a batch-constituent job happens to be batched together with a job
-    /// that exits with an error, the batch-constituent may be considered
-    /// "cancelled".
-    bool jobIsCancelledBatchConstituent(int ReturnCode,
-                                        const Job *ContainerJob,
-                                        const Job *ConstituentJob) {
-      return ReturnCode != 0 &&
-        isBatchJob(ContainerJob) &&
-        jobWasBatchedWithFailingJobs(ConstituentJob);
-    }
-
-    /// Unpack a \c BatchJob that has finished into its constituent \c Job
-    /// members, and call \c taskFinished on each, propagating any \c
-    /// TaskFinishedResponse other than \c
-    /// TaskFinishedResponse::ContinueExecution from any of the constituent
-    /// calls.
-    TaskFinishedResponse
-    unpackAndFinishBatch(int ReturnCode, StringRef Output,
-                         StringRef Errors, const BatchJob *B) {
-      if (Comp.getShowJobLifecycle())
-        llvm::outs() << "Batch job finished: " << LogJob(B) << "\n";
-      auto res = TaskFinishedResponse::ContinueExecution;
-      for (const Job *J : B->getCombinedJobs()) {
-        if (Comp.getShowJobLifecycle())
-          llvm::outs() << "  ==> Unpacked batch constituent finished: "
-                       << LogJob(J) << "\n";
-        auto r = taskFinished(
-            llvm::sys::ProcessInfo::InvalidPid, ReturnCode, Output, Errors,
-            TaskProcessInformation(llvm::sys::ProcessInfo::InvalidPid),
-            (void *)J);
-        if (r != TaskFinishedResponse::ContinueExecution)
-          res = r;
-      }
-      return res;
-    }
-
     void
     emitParseableOutputForEachFinishedJob(ProcessId Pid, int ReturnCode,
                                           StringRef Output,
@@ -451,20 +361,10 @@ namespace driver {
                                           TaskProcessInformation ProcInfo) {
       FinishedCmd->forEachContainedJobAndPID(Pid, [&](const Job *J,
                                                       Job::PID P) {
-        if (jobIsCancelledBatchConstituent(ReturnCode, FinishedCmd, J)) {
-          // Simulate SIGINT-interruption to parseable-output consumer for any
-          // constituent of a failing batch job that produced no errors of its
-          // own.
-          parseable_output::emitSignalledMessage(llvm::errs(),
-                                                 J->getSource().getClassName(),
-                                                 "cancelled batch constituent",
-                                                 "", SIGINT, P, ProcInfo);
-        } else {
           parseable_output::emitFinishedMessage(llvm::errs(),
                                                 J->getSource().getClassName(),
                                                 Output.str(), ReturnCode,
                                                 P, ProcInfo);
-        }
       });
     }
 
@@ -490,11 +390,6 @@ namespace driver {
         Comp.getStatsReporter()->recordJobMaxRSS(
             ProcInfo.getResourceUsage()->Maxrss);
 
-      if (isBatchJob(FinishedCmd)) {
-        return unpackAndFinishBatch(ReturnCode, Output, Errors,
-                                    static_cast<const BatchJob *>(FinishedCmd));
-      }
-
       if (ReturnCode != EXIT_SUCCESS)
         return taskFailed(FinishedCmd, ReturnCode);
 
@@ -522,12 +417,6 @@ namespace driver {
                                  ReturnCode);
       }
 
-      // See how ContinueBuildingAfterErrors gets set up in Driver.cpp for
-      // more info.
-      assert((Comp.getContinueBuildingAfterErrors() ||
-              !Comp.getBatchModeEnabled()) &&
-             "batch mode diagnostics require ContinueBuildingAfterErrors");
-
       return Comp.getContinueBuildingAfterErrors()
                  ? TaskFinishedResponse::ContinueExecution
                  : TaskFinishedResponse::StopExecution;
@@ -636,17 +525,14 @@ namespace driver {
         : Comp(Comp),
           TQ(std::move(TaskQueue)) {}
 
-    /// Schedule and run initial, additional, and batch jobs.
+    /// Schedule and run initial, additional, and single-file jobs.
     void runJobs() {
-      scheduleJobsBeforeBatching();
-      formBatchJobsAndAddPendingJobsToTaskQueue();
+      scheduleJobsForNonIncrementalCompilation();
+      addPendingJobsToTaskQueue();
       runTaskQueueToCompletion();
     }
 
   private:
-    void scheduleJobsBeforeBatching() {
-      scheduleJobsForNonIncrementalCompilation();
-    }
 
     void scheduleJobsForNonIncrementalCompilation() {
       for (const Job *Cmd : Comp.getJobs())
@@ -667,261 +553,9 @@ namespace driver {
       Cmds.clear();
     }
 
-    /// Partition the jobs in \c PendingExecution into those that are \p
-    /// Batchable and those that are \p NonBatchable, clearing \p
-    /// PendingExecution.
-    void getPendingBatchableJobs(CommandSetVector &Batchable,
-                                 CommandSetVector &NonBatchable) {
-      for (const Job *Cmd : PendingExecution) {
-        if (Comp.getToolChain().jobIsBatchable(Comp, Cmd)) {
-          if (Comp.getShowJobLifecycle())
-            llvm::outs() << "Batchable: " << LogJob(Cmd) << "\n";
-          Batchable.insert(Cmd);
-        } else {
-          if (Comp.getShowJobLifecycle())
-            llvm::outs() << "Not batchable: " << LogJob(Cmd) << "\n";
-          NonBatchable.insert(Cmd);
-        }
-      }
-    }
-
-    /// If \p Batch is nonempty, construct a new \c BatchJob from its
-    /// contents by calling \p ToolChain::constructBatchJob, then insert the
-    /// new \c BatchJob into \p Batches.
-    void
-    formBatchJobFromPartitionBatch(std::vector<const Job *> &Batches,
-                                   std::vector<const Job *> const &Batch) {
-      if (Batch.empty())
-        return;
-      if (Comp.getShowJobLifecycle())
-        llvm::outs() << "Forming batch job from "
-                     << Batch.size() << " constituents\n";
-      auto const &TC = Comp.getToolChain();
-      auto J = TC.constructBatchJob(Batch, NextBatchQuasiPID, Comp);
-      if (J)
-        Batches.push_back(Comp.addJob(std::move(J)));
-    }
-
-    /// Build a vector of partition indices, one per Job: the i'th index says
-    /// which batch of the partition the i'th Job will be assigned to. If we are
-    /// shuffling due to -driver-batch-seed, the returned indices will not be
-    /// arranged in contiguous runs. We shuffle partition-indices here, not
-    /// elements themselves, to preserve the invariant that each batch is a
-    /// subsequence of the full set of inputs, not just a subset.
-    std::vector<size_t>
-    assignJobsToPartitions(size_t PartitionSize,
-                           size_t NumJobs) {
-      size_t Remainder = NumJobs % PartitionSize;
-      size_t TargetSize = NumJobs / PartitionSize;
-      std::vector<size_t> PartitionIndex;
-      PartitionIndex.reserve(NumJobs);
-      for (size_t P = 0; P < PartitionSize; ++P) {
-        // Spread remainder evenly across partitions by adding 1 to the target
-        // size of the first Remainder of them.
-        size_t FillCount = TargetSize + ((P < Remainder) ? 1 : 0);
-        std::fill_n(std::back_inserter(PartitionIndex), FillCount, P);
-      }
-      if (Comp.getBatchSeed() != 0) {
-        std::minstd_rand gen(Comp.getBatchSeed());
-        std::shuffle(PartitionIndex.begin(), PartitionIndex.end(), gen);
-      }
-      assert(PartitionIndex.size() == NumJobs);
-      return PartitionIndex;
-    }
-
-    /// Create \c NumberOfParallelCommands batches and assign each job to a
-    /// batch either filling each partition in order or, if seeded with a
-    /// nonzero value, pseudo-randomly (but deterministically and nearly-evenly).
-    void partitionIntoBatches(const llvm::SmallVectorImpl<const Job *> &Batchable,
-                              BatchPartition &Partition) {
-      if (Comp.getShowJobLifecycle()) {
-        llvm::outs() << "Found " << Batchable.size() << " batchable jobs\n";
-        llvm::outs() << "Forming into " << Partition.size() << " batches\n";
-      }
-
-      assert(!Partition.empty());
-      auto PartitionIndex = assignJobsToPartitions(Partition.size(),
-                                                   Batchable.size());
-      assert(PartitionIndex.size() == Batchable.size());
-      auto const &TC = Comp.getToolChain();
-      for_each(Batchable, PartitionIndex, [&](const Job *Cmd, size_t Idx) {
-          assert(Idx < Partition.size());
-          std::vector<const Job*> &P = Partition[Idx];
-          if (P.empty() || TC.jobsAreBatchCombinable(Comp, P[0], Cmd)) {
-            if (Comp.getShowJobLifecycle())
-              llvm::outs() << "Adding " << LogJob(Cmd)
-                           << " to batch " << Idx << '\n';
-            P.push_back(Cmd);
-          } else {
-            // Strange but theoretically possible that we have a batchable job
-            // that's not combinable with others; tack a new batch on for it.
-            if (Comp.getShowJobLifecycle())
-              llvm::outs() << "Adding " << LogJob(Cmd)
-                           << " to new batch " << Partition.size() << '\n';
-            Partition.push_back(std::vector<const Job*>());
-            Partition.back().push_back(Cmd);
-          }
-        });
-    }
-
-    // Selects the number of partitions based on the user-provided batch
-    // count and/or the number of parallel tasks we can run, subject to a
-    // fixed per-batch safety cap, to avoid overcommitting memory.
-    size_t pickNumberOfPartitions() {
-
-      // If the user asked for something, use that.
-      if (Comp.getBatchCount().has_value())
-        return Comp.getBatchCount().value();
-
-      // This is a long comment to justify a simple calculation.
-      //
-      // Because there is a secondary "outer" build system potentially also
-      // scheduling multiple drivers in parallel on separate build targets
-      // -- while we, the driver, schedule our own subprocesses -- we might
-      // be creating up to $NCPU^2 worth of _memory pressure_.
-      //
-      // Oversubscribing CPU is typically no problem these days, but
-      // oversubscribing memory can lead to paging, which on modern systems
-      // is quite bad.
-      //
-      // In practice, $NCPU^2 processes doesn't _quite_ happen: as core
-      // count rises, it usually exceeds the number of large targets
-      // without any dependencies between them (which are the only thing we
-      // have to worry about): you might have (say) 2 large independent
-      // modules * 2 architectures, but that's only an $NTARGET value of 4,
-      // which is much less than $NCPU if you're on a 24 or 36-way machine.
-      //
-      //  So the actual number of concurrent processes is:
-      //
-      //     NCONCUR := $NCPU * min($NCPU, $NTARGET)
-      //
-      // Empirically, a frontend uses about 512kb RAM per non-primary file
-      // and about 10mb per primary. The number of non-primaries per
-      // process is a constant in a given module, but the number of
-      // primaries -- the "batch size" -- is inversely proportional to the
-      // batch count (default: $NCPU). As a result, the memory pressure
-      // we can expect is:
-      //
-      //  $NCONCUR * (($NONPRIMARYMEM * $NFILE) +
-      //              ($PRIMARYMEM * ($NFILE/$NCPU)))
-      //
-      // If we tabulate this across some plausible values, we see
-      // unfortunate memory-pressure results:
-      //
-      //                          $NFILE
-      //                  +---------------------
-      //  $NTARGET $NCPU  |  100    500    1000
-      //  ----------------+---------------------
-      //     2        2   |  2gb   11gb    22gb
-      //     4        4   |  4gb   24gb    48gb
-      //     4        8   |  5gb   28gb    56gb
-      //     4       16   |  7gb   36gb    72gb
-      //     4       36   | 11gb   56gb   112gb
-      //
-      // As it happens, the lower parts of the table are dominated by
-      // number of processes rather than the files-per-batch (the batches
-      // are already quite small due to the high core count) and the left
-      // side of the table is dealing with modules too small to worry
-      // about. But the middle and upper-right quadrant is problematic: 4
-      // and 8 core machines do not typically have 24-48gb of RAM, it'd be
-      // nice not to page on them when building a 4-target project with
-      // 500-file modules.
-      //
-      // Turns we can do that if we just cap the batch size statically at,
-      // say, 25 files per batch, we get a better formula:
-      //
-      //  $NCONCUR * (($NONPRIMARYMEM * $NFILE) +
-      //              ($PRIMARYMEM * min(25, ($NFILE/$NCPU))))
-      //
-      //                          $NFILE
-      //                  +---------------------
-      //  $NTARGET $NCPU  |  100    500    1000
-      //  ----------------+---------------------
-      //     2        2   |  1gb    2gb     3gb
-      //     4        4   |  4gb    8gb    12gb
-      //     4        8   |  5gb   16gb    24gb
-      //     4       16   |  7gb   32gb    48gb
-      //     4       36   | 11gb   56gb   108gb
-      //
-      // This means that the "performance win" of batch mode diminishes
-      // slightly: the batching factor in the equation drops from
-      // ($NFILE/$NCPU) to min(25, $NFILE/$NCPU). In practice this seems to
-      // not cost too much: the additional factor in number of subprocesses
-      // run is the following:
-      //
-      //                          $NFILE
-      //                  +---------------------
-      //  $NTARGET $NCPU  |  100    500    1000
-      //  ----------------+---------------------
-      //     2        2   |  2x    10x      20x
-      //     4        4   |   -     5x      10x
-      //     4        8   |   -   2.5x       5x
-      //     4       16   |   -  1.25x     2.5x
-      //     4       36   |   -      -     1.1x
-      //
-      // Where - means "no difference" because the batches were already
-      // smaller than 25.
-      //
-      // Even in the worst case here, the 1000-file module on 2-core
-      // machine is being built with only 40 subprocesses, rather than the
-      // pre-batch-mode 1000. I.e. it's still running 96% fewer
-      // subprocesses than before. And significantly: it's doing so while
-      // not exceeding the RAM of a typical 2-core laptop.
-
-      // An explanation of why the partition calculation isn't integer division.
-      // Using an example, a module of 26 files exceeds the limit of 25 and must
-      // be compiled in 2 batches. Integer division yields 26/25 = 1 batch, but
-      // a single batch of 26 exceeds the limit. The calculation must round up,
-      // which can be calculated using: `(x + y - 1) / y`
-      auto DivideRoundingUp = [](size_t Num, size_t Div) -> size_t {
-        return (Num + Div - 1) / Div;
-      };
-
-      size_t DefaultSizeLimit = 25;
-      size_t NumTasks = TQ->getNumberOfParallelTasks();
-      size_t NumFiles = PendingExecution.size();
-      size_t SizeLimit = Comp.getBatchSizeLimit().value_or(DefaultSizeLimit);
-      return std::max(NumTasks, DivideRoundingUp(NumFiles, SizeLimit));
-    }
-
-    /// Select jobs that are batch-combinable from \c PendingExecution, combine
-    /// them together into \p BatchJob instances (also inserted into \p
-    /// BatchJobs), and enqueue all \c PendingExecution jobs (whether batched or
-    /// not) into the \c TaskQueue for execution.
-    void formBatchJobsAndAddPendingJobsToTaskQueue() {
-
-      // If batch mode is not enabled, just transfer the set of pending jobs to
-      // the task queue, as-is.
-      if (!Comp.getBatchModeEnabled()) {
-        transferJobsToTaskQueue(PendingExecution, "standard");
-        return;
-      }
-
-      size_t NumPartitions = pickNumberOfPartitions();
-      CommandSetVector Batchable, NonBatchable;
-      std::vector<const Job *> Batches;
-
-      // Split the batchable from non-batchable pending jobs.
-      getPendingBatchableJobs(Batchable, NonBatchable);
-
-      // Partition the batchable jobs into sets.
-      BatchPartition Partition(NumPartitions);
-      partitionIntoBatches(Batchable.takeVector(), Partition);
-
-      // Construct a BatchJob from each batch in the partition.
-      for (auto const &Batch : Partition) {
-        formBatchJobFromPartitionBatch(Batches, Batch);
-      }
-
-      PendingExecution.clear();
-
-      // Save batches so we can locate and decompose them on task-exit.
-      for (const Job *Cmd : Batches)
-        BatchJobs.insert(Cmd);
-
-      // Enqueue the resulting jobs, batched and non-batched alike.
-      transferJobsToTaskQueue(Batches, "batch");
-      transferJobsToTaskQueue(NonBatchable, "non-batch");
+    void addPendingJobsToTaskQueue() {
+      transferJobsToTaskQueue(PendingExecution, "standard");
+      return;
     }
 
     void runTaskQueueToCompletion() {
@@ -958,14 +592,14 @@ namespace driver {
         // there are, we need to continue trying to make progress on the
         // TaskQueue before we start marking deferred jobs as skipped, below.
         if (!PendingExecution.empty() && ResultCode == 0) {
-          formBatchJobsAndAddPendingJobsToTaskQueue();
+          addPendingJobsToTaskQueue();
           continue;
         }
 
         // It's possible that by marking some jobs as skipped, we unblocked
         // some jobs and thus have entries in PendingExecution again; push
         // those through to the TaskQueue.
-        formBatchJobsAndAddPendingJobsToTaskQueue();
+        addPendingJobsToTaskQueue();
 
         // If we added jobs to the TaskQueue, and we are not in an error state,
         // we want to give the TaskQueue another run.
diff --git a/lib/Driver/DarwinToolChains.cpp b/lib/Driver/DarwinToolChains.cpp
index 7d4d7d61071ee..70491e78a1092 100644
--- a/lib/Driver/DarwinToolChains.cpp
+++ b/lib/Driver/DarwinToolChains.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -13,7 +13,7 @@
 #include "ToolChains.h"
 
 #include "swift/AST/DiagnosticsDriver.h"
-#include "swift/AST/PlatformKind.h"
+#include "swift/AST/PlatformKindUtils.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/Platform.h"
@@ -186,7 +186,7 @@ static bool findXcodeClangPath(llvm::SmallVectorImpl<char> &path) {
     // included with an open-source toolchain.
     const char *args[] = {"-toolchain", "default", "-f", "clang", nullptr};
     sys::TaskQueue queue;
-    queue.addTask(xcrunPath->c_str(), args, /*Env=*/std::nullopt,
+    queue.addTask(xcrunPath->c_str(), args, /*Env=*/{},
                   /*Context=*/nullptr,
                   /*SeparateErrors=*/true);
     queue.execute(nullptr,
@@ -366,6 +366,8 @@ toolchains::Darwin::addArgsToLinkStdlib(ArgStringList &Arguments,
       runtimeCompatibilityVersion = llvm::VersionTuple(5, 8);
     } else if (value == "6.0") {
       runtimeCompatibilityVersion = llvm::VersionTuple(6, 0);
+    } else if (value == "6.2") {
+      runtimeCompatibilityVersion = llvm::VersionTuple(6, 2);
     } else if (value == "none") {
       runtimeCompatibilityVersion = std::nullopt;
     } else {
@@ -694,7 +696,7 @@ void toolchains::Darwin::addCommonFrontendArgs(
     llvm::raw_string_ostream os(dwarfVersion);
     os << "-dwarf-version=";
     if (OI.DWARFVersion)
-      os << *OI.DWARFVersion;
+      os << std::to_string(*OI.DWARFVersion);
     else
       os << getDWARFVersionForTriple(getTriple());
   }
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index be3102bce3a69..fc81cd8dd8779 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -97,9 +97,9 @@ void Driver::parseDriverKind(ArrayRef<const char *> Args) {
   std::optional<DriverKind> Kind =
       llvm::StringSwitch<std::optional<DriverKind>>(DriverName)
           .Case("swift", DriverKind::Interactive)
-          .Case("swiftc", DriverKind::Batch)
+          .Case("swiftc", DriverKind::Standard)
           .Case("swift-legacy-driver", DriverKind::Interactive)
-          .Case("swiftc-legacy-driver", DriverKind::Batch)
+          .Case("swiftc-legacy-driver", DriverKind::Standard)
           .Case("sil-opt", DriverKind::SILOpt)
           .Case("sil-func-extractor", DriverKind::SILFuncExtractor)
           .Case("sil-nm", DriverKind::SILNM)
@@ -144,7 +144,8 @@ static void validateLegacyUnsupportedArgs(DiagnosticEngine &diags,
 
 static void validateBridgingHeaderArgs(DiagnosticEngine &diags,
                                        const ArgList &args) {
-  if (!args.hasArgNoClaim(options::OPT_import_objc_header))
+  if (!args.hasArgNoClaim(options::OPT_import_bridging_header,
+                          options::OPT_internal_import_bridging_header))
     return;
 
   if (args.hasArgNoClaim(options::OPT_import_underlying_module))
@@ -193,8 +194,6 @@ static void validateProfilingArgs(DiagnosticEngine &diags,
 
 static void validateDependencyScanningArgs(DiagnosticEngine &diags,
                                            const ArgList &args) {
-  const Arg *ExternalDependencyMap =
-      args.getLastArg(options::OPT_placeholder_dependency_module_map);
   const Arg *ScanDependencies = args.getLastArg(options::OPT_scan_dependencies);
   const Arg *Prescan = args.getLastArg(options::OPT_import_prescan);
 
@@ -207,11 +206,6 @@ static void validateDependencyScanningArgs(DiagnosticEngine &diags,
   const Arg *ValidatePriorCache =
       args.getLastArg(options::OPT_validate_prior_dependency_scan_cache);
 
-  if (ExternalDependencyMap && !ScanDependencies) {
-    diags.diagnose(SourceLoc(), diag::error_requirement_not_met,
-                   "-placeholder-dependency-module-map-file",
-                   "-scan-dependencies");
-  }
   if (Prescan && !ScanDependencies) {
     diags.diagnose(SourceLoc(), diag::error_requirement_not_met,
                    "-import-prescan", "-scan-dependencies");
@@ -462,33 +456,6 @@ static bool getFilelistThreshold(DerivedArgList &Args, size_t &FilelistThreshold
   return false;
 }
 
-static unsigned
-getDriverBatchSeed(llvm::opt::InputArgList &ArgList,
-                   DiagnosticEngine &Diags) {
-  unsigned DriverBatchSeed = 0;
-  if (const Arg *A = ArgList.getLastArg(options::OPT_driver_batch_seed)) {
-    if (StringRef(A->getValue()).getAsInteger(10, DriverBatchSeed)) {
-      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                     A->getAsString(ArgList), A->getValue());
-    }
-  }
-  return DriverBatchSeed;
-}
-
-static std::optional<unsigned>
-getDriverBatchCount(llvm::opt::InputArgList &ArgList, DiagnosticEngine &Diags) {
-  if (const Arg *A = ArgList.getLastArg(options::OPT_driver_batch_count)) {
-    unsigned Count = 0;
-    if (StringRef(A->getValue()).getAsInteger(10, Count)) {
-      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                     A->getAsString(ArgList), A->getValue());
-    } else {
-      return Count;
-    }
-  }
-  return std::nullopt;
-}
-
 static std::string
 computeWorkingDirectory(const llvm::opt::InputArgList *ArgList) {
   if (auto *A = ArgList->getLastArg(options::OPT_working_directory)) {
@@ -535,38 +502,13 @@ createStatsReporter(const llvm::opt::InputArgList *ArgList,
 }
 
 static bool
-computeContinueBuildingAfterErrors(const bool BatchMode,
-                                   const llvm::opt::InputArgList *ArgList) {
-  // Note: Batch mode handling of serialized diagnostics requires that all
-  // batches get to run, in order to make sure that all diagnostics emitted
-  // during the compilation end up in at least one serialized diagnostic file.
-  // Therefore, treat batch mode as implying -continue-building-after-errors.
-  // (This behavior could be limited to only when serialized diagnostics are
-  // being emitted, but this seems more consistent and less surprising for
-  // users.)
+computeContinueBuildingAfterErrors(const llvm::opt::InputArgList *ArgList) {
   // FIXME: We don't really need (or want) a full ContinueBuildingAfterErrors.
   // If we fail to precompile a bridging header, for example, there's no need
   // to go on to compilation of source files, and if compilation of source files
   // fails, we shouldn't try to link. Instead, we'd want to let all jobs finish
   // but not schedule any new ones.
-  return BatchMode ||
-         ArgList->hasArg(options::OPT_continue_building_after_errors);
-
-}
-
-static std::optional<unsigned>
-getDriverBatchSizeLimit(llvm::opt::InputArgList &ArgList,
-                        DiagnosticEngine &Diags) {
-  if (const Arg *A = ArgList.getLastArg(options::OPT_driver_batch_size_limit)) {
-    unsigned Limit = 0;
-    if (StringRef(A->getValue()).getAsInteger(10, Limit)) {
-      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                     A->getAsString(ArgList), A->getValue());
-    } else {
-      return Limit;
-    }
-  }
-  return std::nullopt;
+  return ArgList->hasArg(options::OPT_continue_building_after_errors);
 }
 
 std::unique_ptr<Compilation>
@@ -606,9 +548,8 @@ Driver::buildCompilation(const ToolChain &TC,
 
   // Determine the OutputInfo for the driver.
   OutputInfo OI;
-  bool BatchMode = false;
-  OI.CompilerMode = computeCompilerMode(*TranslatedArgList, Inputs, BatchMode);
-  buildOutputInfo(TC, *TranslatedArgList, BatchMode, Inputs, OI);
+  OI.CompilerMode = computeCompilerMode(*TranslatedArgList, Inputs);
+  buildOutputInfo(TC, *TranslatedArgList, Inputs, OI);
 
   if (Diags.hadAnyError() && !AllowErrors)
     return nullptr;
@@ -668,7 +609,7 @@ Driver::buildCompilation(const ToolChain &TC,
   const bool DriverPrintDerivedOutputFileMap =
       ArgList->hasArg(options::OPT_driver_print_derived_output_file_map);
   const bool ContinueBuildingAfterErrors =
-      computeContinueBuildingAfterErrors(BatchMode, ArgList.get());
+      computeContinueBuildingAfterErrors(ArgList.get());
   const bool ShowJobLifecycle =
       ArgList->hasArg(options::OPT_driver_show_job_lifecycle);
 
@@ -677,11 +618,6 @@ Driver::buildCompilation(const ToolChain &TC,
   // constructor in a block:
   std::unique_ptr<Compilation> C;
   {
-    const unsigned DriverBatchSeed = getDriverBatchSeed(*ArgList, Diags);
-    const std::optional<unsigned> DriverBatchCount =
-        getDriverBatchCount(*ArgList, Diags);
-    const std::optional<unsigned> DriverBatchSizeLimit =
-        getDriverBatchSizeLimit(*ArgList, Diags);
     const bool SaveTemps = ArgList->hasArg(options::OPT_save_temps);
     const bool ShowDriverTimeCompilation =
         ArgList->hasArg(options::OPT_driver_time_compilation);
@@ -699,10 +635,6 @@ Driver::buildCompilation(const ToolChain &TC,
         std::move(TranslatedArgList),
         std::move(Inputs),
         DriverFilelistThreshold,
-        BatchMode,
-        DriverBatchSeed,
-        DriverBatchCount,
-        DriverBatchSizeLimit,
         SaveTemps,
         ShowDriverTimeCompilation,
         std::move(StatsReporter),
@@ -870,7 +802,7 @@ Driver::parseArgStrings(ArrayRef<const char *> Args) {
   unsigned UnsupportedFlag = 0;
   if (driverKind == DriverKind::Interactive)
     UnsupportedFlag = options::NoInteractiveOption;
-  else if (driverKind == DriverKind::Batch)
+  else if (driverKind == DriverKind::Standard)
     UnsupportedFlag = options::NoBatchOption;
 
   if (UnsupportedFlag)
@@ -1076,7 +1008,7 @@ static bool isSDKTooOld(StringRef sdkPath, const llvm::Triple &target) {
 }
 
 void Driver::buildOutputInfo(const ToolChain &TC, const DerivedArgList &Args,
-                             const bool BatchMode, const InputFileList &Inputs,
+                             const InputFileList &Inputs,
                              OutputInfo &OI) const {
 
   if (const Arg *A = Args.getLastArg(options::OPT_lto)) {
@@ -1109,9 +1041,7 @@ void Driver::buildOutputInfo(const ToolChain &TC, const DerivedArgList &Args,
                               : CompilerOutputType;
 
   if (const Arg *A = Args.getLastArg(options::OPT_num_threads)) {
-    if (BatchMode) {
-      Diags.diagnose(SourceLoc(), diag::warning_cannot_multithread_batch_mode);
-    } else if (StringRef(A->getValue()).getAsInteger(10, OI.numThreads)) {
+    if (StringRef(A->getValue()).getAsInteger(10, OI.numThreads)) {
       Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
                      A->getAsString(Args), A->getValue());
     }
@@ -1509,8 +1439,7 @@ void Driver::buildOutputInfo(const ToolChain &TC, const DerivedArgList &Args,
 
 OutputInfo::Mode
 Driver::computeCompilerMode(const DerivedArgList &Args,
-                            const InputFileList &Inputs,
-                            bool &BatchModeOut) const {
+                            const InputFileList &Inputs) const {
 
   if (driverKind == Driver::DriverKind::Interactive)
     return Inputs.empty() ? OutputInfo::Mode::REPL
@@ -1524,10 +1453,6 @@ Driver::computeCompilerMode(const DerivedArgList &Args,
       options::OPT_index_file,
       UseWMO ? options::OPT_whole_module_optimization : llvm::opt::OptSpecifier());
 
-  BatchModeOut = Args.hasFlag(options::OPT_enable_batch_mode,
-                              options::OPT_disable_batch_mode,
-                              false);
-
   // AST dump doesn't work with `-wmo`. Since it's not common to want to dump
   // the AST, we assume that's the priority and ignore `-wmo`, but we warn the
   // user about this decision.
@@ -1538,18 +1463,8 @@ Driver::computeCompilerMode(const DerivedArgList &Args,
     return OutputInfo::Mode::StandardCompile;
   }
 
-  // Override batch mode if given -wmo or -index-file.
-  if (ArgRequiringSingleCompile) {
-    if (BatchModeOut) {
-      BatchModeOut = false;
-      // Emit a warning about such overriding (FIXME: we might conditionalize
-      // this based on the user or xcode passing -disable-batch-mode).
-      Diags.diagnose(SourceLoc(), diag::warn_ignoring_batch_mode,
-                     ArgRequiringSingleCompile->getOption().getPrefixedName());
-    }
+  if (ArgRequiringSingleCompile)
     return OutputInfo::Mode::SingleCompile;
-  }
-
   return OutputInfo::Mode::StandardCompile;
 }
 
@@ -1607,7 +1522,9 @@ void Driver::buildActions(SmallVectorImpl<const Action *> &TopLevelActions,
     if (Args.hasFlag(options::OPT_enable_bridging_pch,
                      options::OPT_disable_bridging_pch,
                      true)) {
-      if (Arg *A = Args.getLastArg(options::OPT_import_objc_header)) {
+      if (Arg *A = Args.getLastArg(
+              options::OPT_import_bridging_header,
+              options::OPT_internal_import_bridging_header)) {
         StringRef Value = A->getValue();
         auto Ty = TC.lookupTypeForExtension(llvm::sys::path::extension(Value));
         if (Ty == file_types::TY_ClangHeader) {
@@ -1708,7 +1625,7 @@ void Driver::buildActions(SmallVectorImpl<const Action *> &TopLevelActions,
       case file_types::TY_SwiftCrossImportDir:
       case file_types::TY_SwiftOverlayFile:
       case file_types::TY_JSONDependencies:
-      case file_types::TY_JSONFeatures:
+      case file_types::TY_JSONArguments:
       case file_types::TY_SwiftABIDescriptor:
       case file_types::TY_SwiftAPIDescriptor:
       case file_types::TY_ConstValues:
@@ -1792,9 +1709,6 @@ void Driver::buildActions(SmallVectorImpl<const Action *> &TopLevelActions,
     AllLinkerInputs.push_back(CA);
     break;
   }
-  case OutputInfo::Mode::BatchModeCompile: {
-    llvm_unreachable("Batch mode should not be used to build actions");
-  }
   case OutputInfo::Mode::Immediate: {
     if (Inputs.empty())
       return;
@@ -2049,6 +1963,49 @@ bool Driver::handleImmediateArgs(const ArgList &Args, const ToolChain &TC) {
     return false;
   }
 
+  if (Args.hasArg(options::OPT_print_supported_features)) {
+    SmallVector<const char *, 5> commandLine;
+    commandLine.push_back("-frontend");
+    commandLine.push_back("-print-supported-features");
+
+    std::string executable = getSwiftProgramPath();
+
+    // FIXME(https://github.com/apple/swift/issues/54554): This bypasses
+    // mechanisms like -v and -###.
+    sys::TaskQueue queue;
+    queue.addTask(executable.c_str(), commandLine);
+    queue.execute(nullptr,
+                  [](sys::ProcessId PID, int returnCode, StringRef output,
+                     StringRef errors, sys::TaskProcessInformation ProcInfo,
+                     void *unused) -> sys::TaskFinishedResponse {
+                    llvm::outs() << output;
+                    llvm::errs() << errors;
+                    return sys::TaskFinishedResponse::ContinueExecution;
+                  });
+    return false;
+  }
+
+  if (Args.hasArg(options::OPT_print_static_build_config)) {
+    SmallVector<const char *, 5> commandLine;
+    commandLine.push_back("-frontend");
+    commandLine.push_back("-print-static-build-config");
+
+    std::string executable = getSwiftProgramPath();
+
+    // FIXME(https://github.com/apple/swift/issues/54554): This bypasses
+    // mechanisms like -v and -###.
+    sys::TaskQueue queue;
+    queue.addTask(executable.c_str(), commandLine);
+    queue.execute(nullptr,
+                  [](sys::ProcessId PID, int returnCode, StringRef output,
+                     StringRef errors, sys::TaskProcessInformation ProcInfo,
+                     void *unused) -> sys::TaskFinishedResponse {
+                    llvm::outs() << output;
+                    llvm::errs() << errors;
+                    return sys::TaskFinishedResponse::ContinueExecution;
+                  });
+    return false;
+  }
   return true;
 }
 
@@ -2687,15 +2644,6 @@ void Driver::computeMainOutput(
       file_types::isAfterLLVM(JA->getType())) {
     // Multi-threaded compilation: A single frontend command produces multiple
     // output file: one for each input files.
-
-    // In batch mode, the driver will try to reserve multiple differing main
-    // outputs to a bridging header. Another assertion will trip, but the cause
-    // will be harder to track down. Since the driver now ignores -num-threads
-    // in batch mode, the user should never be able to falsify this assertion.
-    assert(!C.getBatchModeEnabled() && "Batch mode produces only one main "
-                                       "output per input action, cannot have "
-                                       "batch mode & num-threads");
-
     auto OutputFunc = [&](StringRef Base, StringRef Primary) {
       const TypeToPathMap *OMForInput = nullptr;
       if (OFM)
@@ -2892,7 +2840,6 @@ void Driver::chooseModuleInterfacePath(Compilation &C, const JobAction *JA,
                                        CommandOutput *output) const {
   switch (C.getOutputInfo().CompilerMode) {
   case OutputInfo::Mode::StandardCompile:
-  case OutputInfo::Mode::BatchModeCompile:
     if (!isa<MergeModuleJobAction>(JA))
       return;
     break;
@@ -3124,7 +3071,7 @@ void Driver::printHelp(bool ShowHidden) const {
   case DriverKind::Interactive:
     ExcludedFlagsBitmask |= options::NoInteractiveOption;
     break;
-  case DriverKind::Batch:
+  case DriverKind::Standard:
   case DriverKind::SILOpt:
   case DriverKind::SILFuncExtractor:
   case DriverKind::SILNM:
@@ -3168,7 +3115,6 @@ bool OutputInfo::mightHaveExplicitPrimaryInputs(
     const CommandOutput &Output) const {
   switch (CompilerMode) {
   case Mode::StandardCompile:
-  case Mode::BatchModeCompile:
     return true;
   case Mode::SingleCompile:
     return false;
diff --git a/lib/Driver/Job.cpp b/lib/Driver/Job.cpp
index 2759868355887..31ae11ea0362e 100644
--- a/lib/Driver/Job.cpp
+++ b/lib/Driver/Job.cpp
@@ -486,21 +486,3 @@ StringRef Job::getFirstSwiftPrimaryInput() const {
     return inputInput->getInputArg().getValue();
   return StringRef();
 }
-
-BatchJob::BatchJob(const JobAction &Source,
-                   SmallVectorImpl<const Job *> &&Inputs,
-                   std::unique_ptr<CommandOutput> Output,
-                   const char *Executable, llvm::opt::ArgStringList Arguments,
-                   EnvironmentVector ExtraEnvironment,
-                   std::vector<FilelistInfo> Infos,
-                   ArrayRef<const Job *> Combined, int64_t &NextQuasiPID,
-                   std::optional<ResponseFileInfo> ResponseFile)
-    : Job(Source, std::move(Inputs), std::move(Output), Executable, Arguments,
-          ExtraEnvironment, Infos, ResponseFile),
-      CombinedJobs(Combined.begin(), Combined.end()),
-      QuasiPIDBase(NextQuasiPID) {
-
-  assert(QuasiPIDBase < 0);
-  NextQuasiPID -= CombinedJobs.size();
-  assert(NextQuasiPID < 0);
-}
diff --git a/lib/Driver/ToolChain.cpp b/lib/Driver/ToolChain.cpp
index d9895d51c8522..ceceb9473d9e4 100644
--- a/lib/Driver/ToolChain.cpp
+++ b/lib/Driver/ToolChain.cpp
@@ -72,6 +72,11 @@ std::optional<Job::ResponseFileInfo>
 ToolChain::getResponseFileInfo(const Compilation &C, const char *executablePath,
                                const ToolChain::InvocationInfo &invocationInfo,
                                const ToolChain::JobContext &context) const {
+  // Never use a response file if this is a dummy driver for SourceKit, we
+  // just want the frontend arguments.
+  if (getDriver().isDummyDriverForFrontendInvocation())
+    return std::nullopt;
+
   const bool forceResponseFiles =
       C.getArgs().hasArg(options::OPT_driver_force_response_files);
   assert((invocationInfo.allowsResponseFiles || !forceResponseFiles) &&
@@ -181,113 +186,6 @@ file_types::ID ToolChain::lookupTypeForExtension(StringRef Ext) const {
   return file_types::lookupTypeForExtension(Ext);
 }
 
-static bool jobsHaveSameExecutableNames(const Job *A, const Job *B) {
-  // Jobs that get here (that are derived from CompileJobActions) should always
-  // have the same executable name -- it should always be SWIFT_EXECUTABLE_NAME
-  // -- but we check here just to be sure / fail gracefully in non-assert
-  // builds.
-  assert(strcmp(A->getExecutable(), B->getExecutable()) == 0);
-  if (strcmp(A->getExecutable(), B->getExecutable()) != 0) {
-    return false;
-  }
-  return true;
-}
-
-static bool jobsHaveSameOutputTypes(const Job *A, const Job *B) {
-  if (A->getOutput().getPrimaryOutputType() !=
-      B->getOutput().getPrimaryOutputType())
-    return false;
-  return A->getOutput().hasSameAdditionalOutputTypes(B->getOutput());
-}
-
-static bool jobsHaveSameEnvironment(const Job *A, const Job *B) {
-  auto AEnv = A->getExtraEnvironment();
-  auto BEnv = B->getExtraEnvironment();
-  if (AEnv.size() != BEnv.size())
-    return false;
-  for (size_t i = 0; i < AEnv.size(); ++i) {
-    if (strcmp(AEnv[i].first, BEnv[i].first) != 0)
-      return false;
-    if (strcmp(AEnv[i].second, BEnv[i].second) != 0)
-      return false;
-  }
-  return true;
-}
-
-bool ToolChain::jobIsBatchable(const Compilation &C, const Job *A) const {
-  // FIXME: There might be a tighter criterion to use here?
-  if (C.getOutputInfo().CompilerMode != OutputInfo::Mode::StandardCompile)
-    return false;
-  auto const *CJActA = dyn_cast<const CompileJobAction>(&A->getSource());
-  if (!CJActA)
-    return false;
-  // When having only one job output a dependency file, that job is not
-  // batchable since it has an oddball set of additional output types.
-  if (C.OnlyOneDependencyFile &&
-      A->getOutput().hasAdditionalOutputForType(file_types::TY_Dependencies))
-    return false;
-  return CJActA->findSingleSwiftInput() != nullptr;
-}
-
-bool ToolChain::jobsAreBatchCombinable(const Compilation &C, const Job *A,
-                                       const Job *B) const {
-  assert(jobIsBatchable(C, A));
-  assert(jobIsBatchable(C, B));
-  return (jobsHaveSameExecutableNames(A, B) && jobsHaveSameOutputTypes(A, B) &&
-          jobsHaveSameEnvironment(A, B));
-}
-
-/// Form a synthetic \c CommandOutput for a \c BatchJob by merging together the
-/// \c CommandOutputs of all the jobs passed.
-static std::unique_ptr<CommandOutput>
-makeBatchCommandOutput(ArrayRef<const Job *> jobs, Compilation &C,
-                       file_types::ID outputType) {
-  auto output =
-      std::make_unique<CommandOutput>(outputType, C.getDerivedOutputFileMap());
-  for (auto const *J : jobs) {
-    output->addOutputs(J->getOutput());
-  }
-  return output;
-}
-
-/// Set-union the \c Inputs and \c InputActions from each \c Job in \p jobs into
-/// the provided \p inputJobs and \p inputActions vectors, further adding all \c
-/// Actions in the \p jobs -- InputActions or otherwise -- to \p batchCJA. Do
-/// set-union rather than concatenation here to avoid mentioning the same input
-/// multiple times.
-static bool
-mergeBatchInputs(ArrayRef<const Job *> jobs,
-                 llvm::SmallSetVector<const Job *, 16> &inputJobs,
-                 llvm::SmallSetVector<const Action *, 16> &inputActions,
-                 CompileJobAction *batchCJA) {
-
-  llvm::SmallSetVector<const Action *, 16> allActions;
-
-  for (auto const *J : jobs) {
-    for (auto const *I : J->getInputs()) {
-      inputJobs.insert(I);
-    }
-    auto const *CJA = dyn_cast<CompileJobAction>(&J->getSource());
-    if (!CJA)
-      return true;
-    for (auto const *I : CJA->getInputs()) {
-      // Capture _all_ input actions -- whether or not they are InputActions --
-      // in allActions, to set as the inputs for batchCJA below.
-      allActions.insert(I);
-      // Only collect input actions that _are InputActions_ in the inputActions
-      // array, to load into the JobContext in our caller.
-      if (auto const *IA = dyn_cast<InputAction>(I)) {
-        inputActions.insert(IA);
-      }
-    }
-  }
-
-  for (auto const *I : allActions) {
-    batchCJA->addInput(I);
-  }
-  return false;
-}
-
 void ToolChain::addLinkedLibArgs(const llvm::opt::ArgList &Args,
                                  llvm::opt::ArgStringList &FrontendArgs) {
   Args.getLastArg(options::OPT_l);
@@ -297,62 +195,6 @@ void ToolChain::addLinkedLibArgs(const llvm::opt::ArgList &Args,
   }
 }
 
-/// Construct a \c BatchJob by merging the constituent \p jobs' CommandOutput,
-/// input \c Job and \c Action members. Call through to \c constructInvocation
-/// on \p BatchJob, to build the \c InvocationInfo.
-std::unique_ptr<Job>
-ToolChain::constructBatchJob(ArrayRef<const Job *> unsortedJobs,
-                             Job::PID &NextQuasiPID,
-                             Compilation &C) const {
-  if (unsortedJobs.empty())
-    return nullptr;
-
-  llvm::SmallVector<const Job *, 16> sortedJobs;
-  C.sortJobsToMatchCompilationInputs(unsortedJobs, sortedJobs);
-
-  // Synthetic OutputInfo is a slightly-modified version of the initial
-  // compilation's OI.
-  auto OI = C.getOutputInfo();
-  OI.CompilerMode = OutputInfo::Mode::BatchModeCompile;
-
-  auto const *executablePath = sortedJobs[0]->getExecutable();
-  auto outputType = sortedJobs[0]->getOutput().getPrimaryOutputType();
-  auto output = makeBatchCommandOutput(sortedJobs, C, outputType);
-
-  llvm::SmallSetVector<const Job *, 16> inputJobs;
-  llvm::SmallSetVector<const Action *, 16> inputActions;
-  auto *batchCJA = C.createAction<CompileJobAction>(outputType);
-  if (mergeBatchInputs(sortedJobs, inputJobs, inputActions, batchCJA))
-    return nullptr;
-
-  JobContext context{C, inputJobs.getArrayRef(), inputActions.getArrayRef(),
-                     *output, OI};
-  auto invocationInfo = constructInvocation(*batchCJA, context);
-  // Batch mode can produce quite long command lines; in almost every case these
-  // will trigger use of supplementary output file maps. However, if the driver
-  // command line is long for reasons unrelated to the number of input files,
-  // such as passing a large number of flags, then the individual batch jobs are
-  // also likely to overflow. We have to check for that explicitly here, because
-  // the BatchJob created here does not go through the same code path in
-  // constructJob above.
-  //
-  // The `allowsResponseFiles` flag on the `invocationInfo` we have here exists
-  // only to model external tools that don't know about response files, such as
-  // platform linkers; when talking to the frontend (which we control!) it
-  // should always be true. But double check with an assert here in case someone
-  // failed to set it in `constructInvocation`.
-  assert(invocationInfo.allowsResponseFiles);
-  auto responseFileInfo =
-      getResponseFileInfo(C, executablePath, invocationInfo, context);
-
-  return std::make_unique<BatchJob>(
-      *batchCJA, inputJobs.takeVector(), std::move(output), executablePath,
-      std::move(invocationInfo.Arguments),
-      std::move(invocationInfo.ExtraEnvironment),
-      std::move(invocationInfo.FilelistInfos), sortedJobs, NextQuasiPID,
-      responseFileInfo);
-}
-
 llvm::Expected<file_types::ID>
 ToolChain::remarkFileTypeFromArgs(const llvm::opt::ArgList &Args) const {
   const Arg *A = Args.getLastArg(options::OPT_save_optimization_record_EQ);
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index 4c8fb514d92cf..2d2deec00e082 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -174,7 +174,6 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
     LLVM_FALLTHROUGH;
   case OutputInfo::Mode::StandardCompile:
   case OutputInfo::Mode::SingleCompile:
-  case OutputInfo::Mode::BatchModeCompile:
     arguments.push_back("-target");
     arguments.push_back(inputArgs.MakeArgString(Triple.str()));
     break;
@@ -261,7 +260,7 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
     arguments.push_back("-color-diagnostics");
   }
 
-  inputArgs.AddAllArgs(arguments, options::OPT_I);
+  inputArgs.addAllArgs(arguments, {options::OPT_I, options::OPT_Isystem});
   inputArgs.addAllArgs(arguments, {options::OPT_F, options::OPT_Fsystem});
   inputArgs.AddAllArgs(arguments, options::OPT_vfsoverlay);
 
@@ -284,12 +283,15 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
                                    options::OPT_disable_experimental_feature,
                                    options::OPT_enable_upcoming_feature,
                                    options::OPT_disable_upcoming_feature});
-  inputArgs.AddLastArg(arguments, options::OPT_strict_memory_safety);
+  inputArgs.AddLastArg(arguments, options::OPT_strict_memory_safety,
+                       options::OPT_strict_memory_safety_migrate);
   inputArgs.AddLastArg(arguments, options::OPT_warn_implicit_overrides);
   inputArgs.AddLastArg(arguments, options::OPT_typo_correction_limit);
   inputArgs.AddLastArg(arguments, options::OPT_enable_app_extension);
   inputArgs.AddLastArg(arguments, options::OPT_enable_app_extension_library);
   inputArgs.AddLastArg(arguments, options::OPT_enable_library_evolution);
+  inputArgs.AddLastArg(arguments, options::OPT_default_isolation);
+  inputArgs.AddLastArg(arguments, options::OPT_default_isolation_EQ);
   inputArgs.AddLastArg(arguments, options::OPT_require_explicit_availability);
   inputArgs.AddLastArg(arguments, options::OPT_require_explicit_availability_target);
   inputArgs.AddLastArg(arguments, options::OPT_require_explicit_availability_EQ);
@@ -310,7 +312,6 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
   inputArgs.AddLastArg(arguments, options::OPT_nostdlibimport);
   inputArgs.AddLastArg(arguments, options::OPT_parse_stdlib);
   inputArgs.AddLastArg(arguments, options::OPT_resource_dir);
-  inputArgs.AddLastArg(arguments, options::OPT_solver_memory_threshold);
   inputArgs.AddLastArg(arguments, options::OPT_value_recursion_threshold);
   inputArgs.AddLastArg(arguments, options::OPT_warn_swift3_objc_inference);
   inputArgs.AddLastArg(arguments, options::OPT_Rpass_EQ);
@@ -379,10 +380,6 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
     arguments.push_back(inputArgs.MakeArgString(globalRemapping));
   }
 
-  if (inputArgs.hasArg(options::OPT_executor_factory)) {
-    inputArgs.AddLastArg(arguments, options::OPT_executor_factory);
-  }
-
   // Pass through the values passed to -Xfrontend.
   inputArgs.AddAllArgValues(arguments, options::OPT_Xfrontend);
 
@@ -525,19 +522,28 @@ ToolChain::constructInvocation(const CompileJobAction &job,
   addCommonFrontendArgs(context.OI, context.Output, context.Args, Arguments);
   addRuntimeLibraryFlags(context.OI, Arguments);
 
-  // Pass along an -import-objc-header arg, replacing the argument with the name
-  // of any input PCH to the current action if one is present.
-  if (context.Args.hasArgNoClaim(options::OPT_import_objc_header)) {
+  // Pass along an -(internal-)?import-bridging-header arg, replacing the
+  // argument with the name of any input PCH to the current action if one is
+  // present.
+  if (context.Args.hasArgNoClaim(options::OPT_import_bridging_header,
+                                 options::OPT_internal_import_bridging_header)) {
     bool ForwardAsIs = true;
     bool bridgingPCHIsEnabled =
         context.Args.hasFlag(options::OPT_enable_bridging_pch,
                              options::OPT_disable_bridging_pch, true);
     bool usePersistentPCH = bridgingPCHIsEnabled &&
                             context.Args.hasArg(options::OPT_pch_output_dir);
+    bool isInternalImport = context.Args.getLastArgNoClaim(
+        options::OPT_import_bridging_header,
+        options::OPT_internal_import_bridging_header)
+      ->getOption().getID() == options::OPT_internal_import_bridging_header;
     if (!usePersistentPCH) {
       for (auto *IJ : context.Inputs) {
         if (!IJ->getOutput().getAnyOutputForType(file_types::TY_PCH).empty()) {
-          Arguments.push_back("-import-objc-header");
+          if (isInternalImport)
+            Arguments.push_back("-internal-import-bridging-header");
+          else
+            Arguments.push_back("-import-bridging-header");
           addInputsOfType(Arguments, context.Inputs, context.Args,
                           file_types::TY_PCH);
           ForwardAsIs = false;
@@ -546,13 +552,13 @@ ToolChain::constructInvocation(const CompileJobAction &job,
       }
     }
     if (ForwardAsIs) {
-      context.Args.AddLastArg(Arguments, options::OPT_import_objc_header);
+      context.Args.AddLastArg(Arguments, options::OPT_import_bridging_header,
+                              options::OPT_internal_import_bridging_header);
     }
     if (usePersistentPCH) {
       context.Args.AddLastArg(Arguments, options::OPT_pch_output_dir);
       switch (context.OI.CompilerMode) {
       case OutputInfo::Mode::StandardCompile:
-      case OutputInfo::Mode::BatchModeCompile:
         // In the 'multiple invocations for each file' mode we don't need to
         // validate the PCH every time, it has been validated with the initial
         // -emit-pch invocation.
@@ -710,6 +716,9 @@ ToolChain::constructInvocation(const CompileJobAction &job,
   context.Args.AddLastArg(Arguments, options::OPT_emit_extension_block_symbols,
                           options::OPT_omit_extension_block_symbols);
   context.Args.AddLastArg(Arguments, options::OPT_symbol_graph_minimum_access_level);
+  context.Args.AddLastArg(Arguments, options::OPT_symbol_graph_skip_synthesized_members);
+  context.Args.AddLastArg(Arguments, options::OPT_symbol_graph_skip_inherited_docs);
+  context.Args.AddLastArg(Arguments, options::OPT_symbol_graph_pretty_print);
 
   return II;
 }
@@ -718,7 +727,6 @@ const char *ToolChain::JobContext::computeFrontendModeForCompile() const {
   switch (OI.CompilerMode) {
   case OutputInfo::Mode::StandardCompile:
   case OutputInfo::Mode::SingleCompile:
-  case OutputInfo::Mode::BatchModeCompile:
     break;
   case OutputInfo::Mode::Immediate:
   case OutputInfo::Mode::REPL:
@@ -758,8 +766,8 @@ const char *ToolChain::JobContext::computeFrontendModeForCompile() const {
     return "-emit-imported-modules";
   case file_types::TY_JSONDependencies:
     return "-scan-dependencies";
-  case file_types::TY_JSONFeatures:
-    return "-emit-supported-features";
+  case file_types::TY_JSONArguments:
+    return "-emit-supported-arguments";
   case file_types::TY_IndexData:
     return "-typecheck";
   case file_types::TY_Remapping:
@@ -816,7 +824,6 @@ void ToolChain::JobContext::addFrontendInputAndOutputArguments(
     assert(InputActions.size() == 1 &&
            "Standard-compile mode takes exactly one input (the primary file)");
     break;
-  case OutputInfo::Mode::BatchModeCompile:
   case OutputInfo::Mode::SingleCompile:
     break;
   case OutputInfo::Mode::Immediate:
@@ -975,7 +982,8 @@ ToolChain::constructInvocation(const InterpretJobAction &job,
   addCommonFrontendArgs(context.OI, context.Output, context.Args, Arguments);
   addRuntimeLibraryFlags(context.OI, Arguments);
 
-  context.Args.AddLastArg(Arguments, options::OPT_import_objc_header);
+  context.Args.AddLastArg(Arguments, options::OPT_import_bridging_header,
+                          options::OPT_internal_import_bridging_header);
 
   context.Args.AddLastArg(Arguments, options::OPT_parse_sil);
 
@@ -1045,7 +1053,7 @@ ToolChain::constructInvocation(const BackendJobAction &job,
     case file_types::TY_ClangModuleFile:
     case file_types::TY_IndexData:
     case file_types::TY_JSONDependencies:
-    case file_types::TY_JSONFeatures:
+    case file_types::TY_JSONArguments:
       llvm_unreachable("Cannot be output from backend job");
     case file_types::TY_Swift:
     case file_types::TY_dSYM:
@@ -1083,7 +1091,6 @@ ToolChain::constructInvocation(const BackendJobAction &job,
     }
     break;
   }
-  case OutputInfo::Mode::BatchModeCompile:
   case OutputInfo::Mode::Immediate:
   case OutputInfo::Mode::REPL:
     llvm_unreachable("invalid mode for backend job");
@@ -1115,7 +1122,6 @@ ToolChain::constructInvocation(const BackendJobAction &job,
         context.Args.MakeArgString(OutNames[job.getInputIndex()]));
     break;
   }
-  case OutputInfo::Mode::BatchModeCompile:
   case OutputInfo::Mode::Immediate:
   case OutputInfo::Mode::REPL:
     llvm_unreachable("invalid mode for backend job");
@@ -1238,7 +1244,8 @@ ToolChain::constructInvocation(const MergeModuleJobAction &job,
                           options::OPT_omit_extension_block_symbols);
   context.Args.AddLastArg(Arguments, options::OPT_symbol_graph_minimum_access_level);
 
-  context.Args.AddLastArg(Arguments, options::OPT_import_objc_header);
+  context.Args.AddLastArg(Arguments, options::OPT_import_bridging_header,
+                          options::OPT_internal_import_bridging_header);
 
   Arguments.push_back("-module-name");
   Arguments.push_back(context.Args.MakeArgString(context.OI.ModuleName));
@@ -1281,7 +1288,8 @@ ToolChain::constructInvocation(const VerifyModuleInterfaceJobAction &job,
                    file_types::TY_SerializedDiagnostics,
                    "-serialize-diagnostics-path");
 
-  context.Args.AddLastArg(Arguments, options::OPT_import_objc_header);
+  context.Args.AddLastArg(Arguments, options::OPT_import_bridging_header,
+                          options::OPT_internal_import_bridging_header);
 
   Arguments.push_back("-module-name");
   Arguments.push_back(context.Args.MakeArgString(context.OI.ModuleName));
@@ -1347,7 +1355,8 @@ ToolChain::constructInvocation(const REPLJobAction &job,
   addCommonFrontendArgs(context.OI, context.Output, context.Args, FrontendArgs);
   addRuntimeLibraryFlags(context.OI, FrontendArgs);
 
-  context.Args.AddLastArg(FrontendArgs, options::OPT_import_objc_header);
+  context.Args.AddLastArg(FrontendArgs, options::OPT_import_bridging_header,
+                          options::OPT_internal_import_bridging_header);
   context.Args.addAllArgs(FrontendArgs,
                           {options::OPT_framework, options::OPT_L});
   ToolChain::addLinkedLibArgs(context.Args, FrontendArgs);
@@ -1657,9 +1666,10 @@ const char *ToolChain::getClangLinkerDriver(
   // a C++ standard library if it's not needed, in particular because the
   // standard library that `clang++` selects by default may not be the one that
   // is desired.
-  const char *LinkerDriver =
-      Args.hasArg(options::OPT_enable_experimental_cxx_interop) ? "clang++"
-                                                                : "clang";
+  bool useCxxLinker = Args.hasArg(options::OPT_enable_experimental_cxx_interop);
+  if (Arg *arg = Args.getLastArg(options::OPT_cxx_interoperability_mode))
+      useCxxLinker |= StringRef(arg->getValue()) != "off";
+  const char *LinkerDriver = useCxxLinker ? "clang++" : "clang";
   if (const Arg *A = Args.getLastArg(options::OPT_tools_directory)) {
     StringRef toolchainPath(A->getValue());
 
diff --git a/lib/Driver/UnixToolChains.cpp b/lib/Driver/UnixToolChains.cpp
index a8a934da16d2e..12b0a895812ec 100644
--- a/lib/Driver/UnixToolChains.cpp
+++ b/lib/Driver/UnixToolChains.cpp
@@ -86,51 +86,9 @@ ToolChain::InvocationInfo toolchains::GenericUnix::constructInvocation(
 
   return II;
 }
-// Amazon Linux 2023 requires lld as the default linker.
-bool isAmazonLinux2023Host() {
-      std::ifstream file("/etc/os-release");
-      std::string line;
-
-      while (std::getline(file, line)) {
-        if (line.substr(0, 12) == "PRETTY_NAME=") {
-          if (line.substr(12) == "\"Amazon Linux 2023\"") {
-            file.close();
-            return true;
-          }
-        }
-      }
-      return false;
-    }
 
 std::string toolchains::GenericUnix::getDefaultLinker() const {
-  if (getTriple().isAndroid() || isAmazonLinux2023Host()
-      || (getTriple().isMusl()
-          && getTriple().getVendor() == llvm::Triple::Swift))
-    return "lld";
-
-  switch (getTriple().getArch()) {
-  case llvm::Triple::arm:
-  case llvm::Triple::aarch64:
-  case llvm::Triple::aarch64_32:
-  case llvm::Triple::armeb:
-  case llvm::Triple::thumb:
-  case llvm::Triple::thumbeb:
-    // BFD linker has issues wrt relocation of the protocol conformance
-    // section on these targets, it also generates COPY relocations for
-    // final executables, as such, unless specified, we default to gold
-    // linker.
-    return "gold";
-  case llvm::Triple::x86:
-  case llvm::Triple::x86_64:
-  case llvm::Triple::ppc64:
-  case llvm::Triple::ppc64le:
-  case llvm::Triple::systemz:
-    // BFD linker has issues wrt relocations against protected symbols.
-    return "gold";
-  default:
-    // Otherwise, use the default BFD linker.
-    return "";
-  }
+  return "";
 }
 
 bool toolchains::GenericUnix::addRuntimeRPath(const llvm::Triple &T,
@@ -376,10 +334,9 @@ toolchains::GenericUnix::constructInvocation(const DynamicLinkJobAction &job,
     SmallString<128> LibProfile(SharedResourceDirPath);
     llvm::sys::path::remove_filename(LibProfile); // remove platform name
     llvm::sys::path::append(LibProfile, "clang", "lib");
-
-    llvm::sys::path::append(LibProfile, getTriple().getOSName(),
-                            Twine("libclang_rt.profile-") +
-                                getTriple().getArchName() + ".a");
+    llvm::sys::path::append(
+        LibProfile, getUnversionedTriple(getTriple()).getOSName(),
+        Twine("libclang_rt.profile-") + getTriple().getArchName() + ".a");
     Arguments.push_back(context.Args.MakeArgString(LibProfile));
     Arguments.push_back(context.Args.MakeArgString(
         Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
diff --git a/lib/Driver/WebAssemblyToolChains.cpp b/lib/Driver/WebAssemblyToolChains.cpp
index eb257f1ddbffe..3d09649edd4c5 100644
--- a/lib/Driver/WebAssemblyToolChains.cpp
+++ b/lib/Driver/WebAssemblyToolChains.cpp
@@ -188,12 +188,16 @@ toolchains::WebAssembly::constructInvocation(const DynamicLinkJobAction &job,
 
   // WebAssembly doesn't reserve low addresses But without "extra inhabitants"
   // of the pointer representation, runtime performance and memory footprint are
-  // worse. So assume that compiler driver uses wasm-ld and --global-base=1024
-  // to reserve low 1KB.
+  // worse. So assume that compiler driver uses wasm-ld and --global-base=4096
+  // to reserve low 4KB.
   Arguments.push_back("-Xlinker");
   Arguments.push_back(context.Args.MakeArgString(
       Twine("--global-base=") +
       std::to_string(SWIFT_ABI_WASM32_LEAST_VALID_POINTER)));
+  Arguments.push_back("-Xlinker");
+  Arguments.push_back(context.Args.MakeArgString(
+      Twine("--table-base=") +
+      std::to_string(SWIFT_ABI_WASM32_LEAST_VALID_POINTER)));
 
   // These custom arguments should be right before the object file at the end.
   context.Args.AddAllArgs(Arguments, options::OPT_linker_option_Group);
diff --git a/lib/DriverTool/sil_func_extractor_main.cpp b/lib/DriverTool/sil_func_extractor_main.cpp
index 9ff267001ab53..23aa3e04ec168 100644
--- a/lib/DriverTool/sil_func_extractor_main.cpp
+++ b/lib/DriverTool/sil_func_extractor_main.cpp
@@ -118,12 +118,6 @@ struct SILFuncExtractorOptions {
                  llvm::cl::init(false),
                  llvm::cl::desc("Do not dump AST."));
 
-  llvm::cl::opt<bool> EnableOSSAModules = llvm::cl::opt<bool>(
-      "enable-ossa-modules", llvm::cl::init(true),
-      llvm::cl::desc("Do we always serialize SIL in OSSA form? If "
-                     "this is disabled we do not serialize in OSSA "
-                     "form when optimizing."));
-
   llvm::cl::opt<llvm::cl::boolOrDefault>
     EnableObjCInterop = llvm::cl::opt<llvm::cl::boolOrDefault>(
       "enable-objc-interop",
@@ -275,7 +269,6 @@ int sil_func_extractor_main(ArrayRef<const char *> argv, void *MainAddr) {
   SILOptions &Opts = Invocation.getSILOptions();
   Opts.EmitVerboseSIL = options.EmitVerboseSIL;
   Opts.EmitSortedSIL = options.EmitSortedSIL;
-  Opts.EnableOSSAModules = options.EnableOSSAModules;
   Opts.StopOptimizationAfterSerialization |= options.EmitSIB;
 
   serialization::ExtendedValidationInfo extendedInfo;
@@ -368,7 +361,6 @@ int sil_func_extractor_main(ArrayRef<const char *> argv, void *MainAddr) {
     serializationOpts.OutputPath = OutputFile;
     serializationOpts.SerializeAllSIL = true;
     serializationOpts.IsSIB = true;
-    serializationOpts.IsOSSA = options.EnableOSSAModules;
 
     symbolgraphgen::SymbolGraphOptions symbolGraphOpts;
 
diff --git a/lib/DriverTool/sil_llvm_gen_main.cpp b/lib/DriverTool/sil_llvm_gen_main.cpp
index 9bc9a2debe961..713ad907ab005 100644
--- a/lib/DriverTool/sil_llvm_gen_main.cpp
+++ b/lib/DriverTool/sil_llvm_gen_main.cpp
@@ -22,6 +22,7 @@
 #include "swift/AST/SILOptions.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/LLVMInitialize.h"
+#include "swift/Basic/QuotedString.h"
 #include "swift/Frontend/DiagnosticVerifier.h"
 #include "swift/Frontend/Frontend.h"
 #include "swift/Frontend/PrintingDiagnosticConsumer.h"
@@ -49,6 +50,29 @@
 #include <cstdio>
 using namespace swift;
 
+namespace {
+enum class SILOptStrictConcurrency {
+  None = 0,
+  Complete,
+  Targeted,
+  Minimal,
+};
+}
+
+static std::optional<StrictConcurrency>
+convertSILOptToRawStrictConcurrencyLevel(SILOptStrictConcurrency level) {
+  switch (level) {
+  case SILOptStrictConcurrency::None:
+    return {};
+  case SILOptStrictConcurrency::Complete:
+    return StrictConcurrency::Complete;
+  case SILOptStrictConcurrency::Targeted:
+    return StrictConcurrency::Targeted;
+  case SILOptStrictConcurrency::Minimal:
+    return StrictConcurrency::Minimal;
+  }
+}
+
 struct SILLLVMGenOptions {
   llvm::cl::opt<std::string>
     InputFilename = llvm::cl::opt<std::string>(llvm::cl::desc("input file"),
@@ -66,12 +90,29 @@ struct SILLLVMGenOptions {
     FrameworkPaths = llvm::cl::list<std::string>(
       "F", llvm::cl::desc("add a directory to the framework search path"));
 
+  llvm::cl::list<std::string> VFSOverlays = llvm::cl::list<std::string>(
+      "vfsoverlay", llvm::cl::desc("add a VFS overlay"));
+
   llvm::cl::opt<std::string>
     ModuleName = llvm::cl::opt<std::string>("module-name",
                  llvm::cl::desc("The name of the module if processing"
                                 " a module. Necessary for processing "
                                 "stdin."));
 
+  llvm::cl::opt<bool> StrictImplicitModuleContext = llvm::cl::opt<bool>(
+      "strict-implicit-module-context",
+      llvm::cl::desc("Enable the strict forwarding of compilation "
+                     "context to downstream implicit module dependencies"));
+
+  llvm::cl::opt<bool> DisableImplicitModules =
+      llvm::cl::opt<bool>("disable-implicit-swift-modules",
+                          llvm::cl::desc("Disable implicit swift modules."));
+
+  llvm::cl::opt<std::string> ExplicitSwiftModuleMapPath =
+      llvm::cl::opt<std::string>(
+          "explicit-swift-module-map-file",
+          llvm::cl::desc("Explict swift module map file path"));
+
   llvm::cl::opt<std::string>
     ResourceDir = llvm::cl::opt<std::string>(
       "resource-dir",
@@ -96,37 +137,140 @@ struct SILLLVMGenOptions {
   llvm::cl::opt<bool>
     PerformWMO = llvm::cl::opt<bool>("wmo", llvm::cl::desc("Enable whole-module optimizations"));
 
-  llvm::cl::opt<IRGenOutputKind>
-    OutputKind = llvm::cl::opt<IRGenOutputKind>(
+  llvm::cl::opt<IRGenOutputKind> OutputKind = llvm::cl::opt<IRGenOutputKind>(
       "output-kind", llvm::cl::desc("Type of output to produce"),
-      llvm::cl::values(clEnumValN(IRGenOutputKind::LLVMAssemblyAfterOptimization,
-                                  "llvm-as", "Emit llvm assembly"),
-                       clEnumValN(IRGenOutputKind::LLVMBitcode, "llvm-bc",
-                                  "Emit llvm bitcode"),
-                       clEnumValN(IRGenOutputKind::NativeAssembly, "as",
-                                  "Emit native assembly"),
-                       clEnumValN(IRGenOutputKind::ObjectFile, "object",
-                                  "Emit an object file")),
+      llvm::cl::values(
+          clEnumValN(IRGenOutputKind::LLVMAssemblyBeforeOptimization, "llvm-as",
+                     "Emit llvm assembly before optimization"),
+          clEnumValN(IRGenOutputKind::LLVMAssemblyAfterOptimization,
+                     "llvm-as-opt", "Emit llvm assembly after optimization"),
+          clEnumValN(IRGenOutputKind::LLVMBitcode, "llvm-bc",
+                     "Emit llvm bitcode"),
+          clEnumValN(IRGenOutputKind::NativeAssembly, "as",
+                     "Emit native assembly"),
+          clEnumValN(IRGenOutputKind::ObjectFile, "object",
+                     "Emit an object file")),
       llvm::cl::init(IRGenOutputKind::ObjectFile));
 
   llvm::cl::opt<bool>
     DisableLegacyTypeInfo = llvm::cl::opt<bool>("disable-legacy-type-info",
           llvm::cl::desc("Don't try to load backward deployment layouts"));
+
+  llvm::cl::opt<std::string> SwiftVersionString = llvm::cl::opt<std::string>(
+      "swift-version",
+      llvm::cl::desc(
+          "The swift version to assume AST declarations correspond to"));
+
+  llvm::cl::opt<bool> EnableExperimentalConcurrency = llvm::cl::opt<bool>(
+      "enable-experimental-concurrency",
+      llvm::cl::desc("Enable experimental concurrency model."));
+
+  llvm::cl::opt<llvm::cl::boolOrDefault> EnableExperimentalMoveOnly =
+      llvm::cl::opt<llvm::cl::boolOrDefault>(
+          "enable-experimental-move-only", llvm::cl::init(llvm::cl::BOU_UNSET),
+          llvm::cl::desc("Enable experimental move-only semantics."));
+
+  llvm::cl::list<std::string> ExperimentalFeatures =
+      llvm::cl::list<std::string>(
+          "enable-experimental-feature",
+          llvm::cl::desc("Enable the given experimental feature."));
+
+  llvm::cl::list<std::string> UpcomingFeatures = llvm::cl::list<std::string>(
+      "enable-upcoming-feature",
+      llvm::cl::desc("Enable the given upcoming feature."));
+
+  llvm::cl::opt<bool> EnableCxxInterop = llvm::cl::opt<bool>(
+      "enable-experimental-cxx-interop", llvm::cl::desc("Enable C++ interop."),
+      llvm::cl::init(false));
+
+  llvm::cl::opt<bool> EnableObjCInterop = llvm::cl::opt<bool>(
+      "enable-objc-interop",
+      llvm::cl::desc("Enable Objective-C interoperability."));
+
+  llvm::cl::opt<bool> DisableObjCInterop = llvm::cl::opt<bool>(
+      "disable-objc-interop",
+      llvm::cl::desc("Disable Objective-C interoperability."));
+
+  // Strict Concurrency
+  llvm::cl::opt<SILOptStrictConcurrency> StrictConcurrencyLevel =
+      llvm::cl::opt<SILOptStrictConcurrency>(
+          "strict-concurrency", llvm::cl::desc("strict concurrency level"),
+          llvm::cl::init(SILOptStrictConcurrency::None),
+          llvm::cl::values(
+              clEnumValN(SILOptStrictConcurrency::Complete, "complete",
+                         "Enable complete strict concurrency"),
+              clEnumValN(SILOptStrictConcurrency::Targeted, "targeted",
+                         "Enable targeted strict concurrency"),
+              clEnumValN(SILOptStrictConcurrency::Minimal, "minimal",
+                         "Enable minimal strict concurrency"),
+              clEnumValN(SILOptStrictConcurrency::None, "disabled",
+                         "Strict concurrency disabled")));
+};
+
+static std::optional<bool> toOptionalBool(llvm::cl::boolOrDefault defaultable) {
+  switch (defaultable) {
+  case llvm::cl::BOU_TRUE:
+    return true;
+  case llvm::cl::BOU_FALSE:
+    return false;
+  case llvm::cl::BOU_UNSET:
+    return std::nullopt;
+  }
+  llvm_unreachable("Bad case for llvm::cl::boolOrDefault!");
+}
+
+namespace {
+class LLVMOptionFilter {
+  /// Options with -Xllvm removed. We let through -Xllvm options so that LLVM's
+  /// processing can find it.
+  SmallVector<const char *, 32> filteredOptions;
+
+  /// Options with the -Xllvm prefix. We have that here so we can process them
+  /// separately.
+  SmallVector<const char *, 32> llvmOptions;
+
+public:
+  LLVMOptionFilter(ArrayRef<const char *> argv) {
+    for (unsigned i = 0; i < argv.size(); ++i) {
+      // Not a -Xllvm option... just let it through.
+      if (StringRef(argv[i]) != "-Xllvm") {
+        filteredOptions.push_back(argv[i]);
+        continue;
+      }
+
+      assert(i + 1 < argv.size() && "-Xllvm without a corresponding option");
+      ++i;
+      filteredOptions.push_back(argv[i]);
+      llvmOptions.push_back(argv[i]);
+    }
+  }
+
+  ArrayRef<const char *> getFilteredOptions() const { return filteredOptions; }
+  ArrayRef<const char *> getLLVMOptions() const { return llvmOptions; }
 };
+} // namespace
 
 int sil_llvm_gen_main(ArrayRef<const char *> argv, void *MainAddr) {
   INITIALIZE_LLVM();
 
-  SILLLVMGenOptions options;
-
-  llvm::cl::ParseCommandLineOptions(argv.size(), argv.data(), "Swift LLVM IR Generator\n");
+  llvm::setBugReportMsg(SWIFT_CRASH_BUG_REPORT_MESSAGE "\n");
+  llvm::EnablePrettyStackTraceOnSigInfoForThisThread();
 
-  if (options.PrintStats)
-    llvm::EnableStatistics();
+  SILLLVMGenOptions options;
+  LLVMOptionFilter filteredOptions(argv);
 
   CompilerInvocation Invocation;
 
   Invocation.setMainExecutablePath(llvm::sys::fs::getMainExecutable(argv[0], MainAddr));
+  copy(filteredOptions.getLLVMOptions(),
+       std::back_inserter(Invocation.getFrontendOptions().LLVMArgs));
+
+  llvm::cl::ParseCommandLineOptions(filteredOptions.getFilteredOptions().size(),
+                                    filteredOptions.getFilteredOptions().data(),
+                                    "Swift LLVM IR Generator\n");
+
+  if (options.PrintStats)
+    llvm::EnableStatistics();
 
   // Give the context the list of search paths to use for modules.
   std::vector<SearchPathOptions::SearchPath> ImportPaths;
@@ -139,6 +283,9 @@ int sil_llvm_gen_main(ArrayRef<const char *> argv, void *MainAddr) {
     FramePaths.push_back({path, /*isSystem=*/false});
   }
   Invocation.setFrameworkSearchPaths(FramePaths);
+
+  Invocation.setVFSOverlays(options.VFSOverlays);
+
   // Set the SDK path and target if given.
   if (options.SDKPath.getNumOccurrences() == 0) {
     const char *SDKROOT = getenv("SDKROOT");
@@ -151,22 +298,116 @@ int sil_llvm_gen_main(ArrayRef<const char *> argv, void *MainAddr) {
     Invocation.setTargetTriple(options.Target);
   if (!options.ResourceDir.empty())
     Invocation.setRuntimeResourcePath(options.ResourceDir);
+
+  Invocation.getFrontendOptions().StrictImplicitModuleContext =
+      options.StrictImplicitModuleContext;
+
+  Invocation.getFrontendOptions().DisableImplicitModules =
+      options.DisableImplicitModules;
+  Invocation.getSearchPathOptions().ExplicitSwiftModuleMapPath =
+      options.ExplicitSwiftModuleMapPath;
+
   // Set the module cache path. If not passed in we use the default swift module
   // cache.
   Invocation.getClangImporterOptions().ModuleCachePath = options.ModuleCachePath;
   Invocation.setParseStdlib();
 
   // Setup the language options
-  auto &LangOpts = Invocation.getLangOptions();
-  LangOpts.DisableAvailabilityChecking = true;
-  LangOpts.EnableAccessControl = false;
-  LangOpts.EnableObjCAttrRequiresFoundation = false;
-  LangOpts.EnableObjCInterop = LangOpts.Target.isOSDarwin();
+  if (options.SwiftVersionString.size()) {
+    auto vers = VersionParser::parseVersionString(options.SwiftVersionString,
+                                                  SourceLoc(), nullptr);
+    bool isValid = false;
+    if (vers.has_value()) {
+      if (auto effectiveVers = vers.value().getEffectiveLanguageVersion()) {
+        Invocation.getLangOptions().EffectiveLanguageVersion =
+            effectiveVers.value();
+        isValid = true;
+      }
+    }
+    if (!isValid) {
+      llvm::errs() << "error: invalid swift version "
+                   << options.SwiftVersionString << '\n';
+      exit(-1);
+    }
+  }
+  Invocation.getLangOptions().DisableAvailabilityChecking = true;
+  Invocation.getLangOptions().EnableAccessControl = false;
+  Invocation.getLangOptions().EnableObjCAttrRequiresFoundation = false;
+  Invocation.getLangOptions().EnableDeserializationSafety = false;
+  Invocation.getLangOptions().EnableExperimentalConcurrency =
+      options.EnableExperimentalConcurrency;
+  std::optional<bool> enableExperimentalMoveOnly =
+      toOptionalBool(options.EnableExperimentalMoveOnly);
+  if (enableExperimentalMoveOnly && *enableExperimentalMoveOnly) {
+    // FIXME: drop addition of Feature::MoveOnly once its queries are gone.
+    Invocation.getLangOptions().enableFeature(Feature::MoveOnly);
+    Invocation.getLangOptions().enableFeature(Feature::NoImplicitCopy);
+    Invocation.getLangOptions().enableFeature(
+        Feature::OldOwnershipOperatorSpellings);
+  }
+
+  for (auto &featureName : options.UpcomingFeatures) {
+    auto feature = Feature::getUpcomingFeature(featureName);
+    if (!feature) {
+      llvm::errs() << "error: unknown upcoming feature "
+                   << QuotedString(featureName) << "\n";
+      exit(-1);
+    }
+
+    if (auto firstVersion = feature->getLanguageVersion()) {
+      if (Invocation.getLangOptions().isSwiftVersionAtLeast(*firstVersion)) {
+        llvm::errs() << "error: upcoming feature " << QuotedString(featureName)
+                     << " is already enabled as of Swift version "
+                     << *firstVersion << '\n';
+        exit(-1);
+      }
+    }
+    Invocation.getLangOptions().enableFeature(*feature);
+  }
+
+  for (auto &featureName : options.ExperimentalFeatures) {
+    if (auto feature = Feature::getExperimentalFeature(featureName)) {
+      Invocation.getLangOptions().enableFeature(*feature);
+    } else {
+      llvm::errs() << "error: unknown experimental feature "
+                   << QuotedString(featureName) << "\n";
+      exit(-1);
+    }
+  }
+
+  // Enable strict concurrency if we have the feature specified or if it was
+  // specified via a command line option to sil-opt.
+  if (Invocation.getLangOptions().hasFeature(Feature::StrictConcurrency)) {
+    Invocation.getLangOptions().StrictConcurrencyLevel =
+        StrictConcurrency::Complete;
+  } else if (auto level = convertSILOptToRawStrictConcurrencyLevel(
+                 options.StrictConcurrencyLevel)) {
+    // If strict concurrency was enabled from the cmdline so the feature flag as
+    // well.
+    if (*level == StrictConcurrency::Complete)
+      Invocation.getLangOptions().enableFeature(Feature::StrictConcurrency);
+    Invocation.getLangOptions().StrictConcurrencyLevel = *level;
+  }
+
+  // If we have strict concurrency set as a feature and were told to turn off
+  // region-based isolation... do so now.
+  if (Invocation.getLangOptions().hasFeature(Feature::StrictConcurrency)) {
+    Invocation.getLangOptions().enableFeature(Feature::RegionBasedIsolation);
+  }
+
+  Invocation.getLangOptions().EnableObjCInterop =
+      options.EnableObjCInterop    ? true
+      : options.DisableObjCInterop ? false
+                                   : llvm::Triple(options.Target).isOSDarwin();
+
+  Invocation.getLangOptions().EnableCXXInterop = options.EnableCxxInterop;
+  Invocation.computeCXXStdlibOptions();
 
   // Setup the IRGen Options.
   IRGenOptions &Opts = Invocation.getIRGenOptions();
   Opts.OutputKind = options.OutputKind;
   Opts.DisableLegacyTypeInfo = options.DisableLegacyTypeInfo;
+  Invocation.computeAArch64TBIOptions();
 
   serialization::ExtendedValidationInfo extendedInfo;
   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> FileBufOrErr =
@@ -216,16 +457,35 @@ int sil_llvm_gen_main(ArrayRef<const char *> argv, void *MainAddr) {
       return IRGenDescriptor::forWholeModule(
           mod, Opts, TBDOpts, SILOpts, SILTypes,
           /*SILMod*/ nullptr, moduleName, PSPs);
-    } else {
-      return IRGenDescriptor::forFile(
-          mod->getFiles()[0], Opts, TBDOpts, SILOpts, SILTypes,
-          /*SILMod*/ nullptr, moduleName, PSPs, /*discriminator*/ "");
     }
+
+    return IRGenDescriptor::forFile(
+        mod->getFiles()[0], Opts, TBDOpts, SILOpts, SILTypes,
+        /*SILMod*/ nullptr, moduleName, PSPs, /*discriminator*/ "");
   };
 
   auto &eval = CI.getASTContext().evaluator;
   auto desc = getDescriptor();
   desc.out = &outFile->getOS();
+
+  if (options.OutputKind == IRGenOutputKind::LLVMAssemblyBeforeOptimization) {
+    // We need to perform Sema here since IRGenRequest itself does not perform
+    // Sema (unlike OptimizedIRRequest).
+    CI.performSema();
+
+    // If Sema produced an error, exit early.
+    bool HadError = CI.getASTContext().hadError();
+    if (HadError)
+      exit(-1);
+
+    auto generatedMod = evaluateOrFatal(eval, IRGenRequest{desc});
+    if (!generatedMod)
+      return 1;
+
+    generatedMod.getModule()->print(*outFile, nullptr);
+    return 0;
+  }
+
   auto generatedMod = evaluateOrFatal(eval, OptimizedIRRequest{desc});
   if (!generatedMod)
     return 1;
diff --git a/lib/DriverTool/sil_opt_main.cpp b/lib/DriverTool/sil_opt_main.cpp
index 1df3da95978bf..aa4f7a5278313 100644
--- a/lib/DriverTool/sil_opt_main.cpp
+++ b/lib/DriverTool/sil_opt_main.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -115,8 +115,11 @@ operator<<(raw_ostream &os, const std::optional<CopyPropagationOption> option) {
     case CopyPropagationOption::RequestedPassesOnly:
       os << "requested-passes-only";
       break;
-    case CopyPropagationOption::On:
-      os << "on";
+    case CopyPropagationOption::Optimizing:
+      os << "optimizing";
+      break;
+    case CopyPropagationOption::Always:
+      os << "always";
       break;
     }
   } else {
@@ -135,24 +138,27 @@ class parser<std::optional<CopyPropagationOption>>
   // parse - Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg,
              std::optional<CopyPropagationOption> &Value) {
-    if (Arg == "" || Arg == "true" || Arg == "TRUE" || Arg == "True" ||
-        Arg == "1") {
-      Value = CopyPropagationOption::On;
+    if (Arg.compare_insensitive("always")) {
+      Value = CopyPropagationOption::Always;
+      return false;
+    }
+    if (Arg.compare_insensitive("optimizing")) {
+      Value = CopyPropagationOption::Optimizing;
       return false;
     }
-    if (Arg == "false" || Arg == "FALSE" || Arg == "False" || Arg == "0") {
+    if (Arg.compare_insensitive("false") || Arg.compare_insensitive("off") ||
+        Arg == "0") {
       Value = CopyPropagationOption::Off;
       return false;
     }
-    if (Arg == "requested-passes-only" || Arg == "REQUESTED-PASSES-ONLY" ||
-        Arg == "Requested-Passes-Only") {
+    if (Arg.compare_insensitive("requested-passes-only")) {
       Value = CopyPropagationOption::RequestedPassesOnly;
       return false;
     }
 
     return O.error("'" + Arg +
-                   "' is invalid for CopyPropagationOption! Try true, false, "
-                   "or requested-passes-only.");
+                   "' is invalid for CopyPropagationOption!"
+                   " Try always, optimizing, or requested-passes-only.");
   }
 
   void initialize() {}
@@ -310,12 +316,6 @@ struct SILOptOptions {
   EnableMoveInoutStackProtection = llvm::cl::opt<bool>("enable-move-inout-stack-protector",
                     llvm::cl::desc("Enable the stack protector by moving values to temporaries."));
 
-  llvm::cl::opt<bool> EnableOSSAModules = llvm::cl::opt<bool>(
-      "enable-ossa-modules", llvm::cl::init(true),
-      llvm::cl::desc("Do we always serialize SIL in OSSA form? If "
-                     "this is disabled we do not serialize in OSSA "
-                     "form when optimizing."));
-
   cl::opt<EnforceExclusivityMode>
     EnforceExclusivity = cl::opt<EnforceExclusivityMode>(
     "enforce-exclusivity", cl::desc("Enforce law of exclusivity "
@@ -597,6 +597,16 @@ struct SILOptOptions {
       "enable-address-dependencies",
       llvm::cl::desc("Enable enforcement of lifetime dependencies on addressable values."));
 
+  llvm::cl::opt<bool> EnableCalleeAllocatedCoroAbi = llvm::cl::opt<bool>(
+      "enable-callee-allocated-coro-abi",
+      llvm::cl::desc("Override per-platform settings and use yield_once_2."),
+      llvm::cl::init(false));
+  llvm::cl::opt<bool> DisableCalleeAllocatedCoroAbi = llvm::cl::opt<bool>(
+      "disable-callee-allocated-coro-abi",
+      llvm::cl::desc(
+          "Override per-platform settings and don't use yield_once_2."),
+      llvm::cl::init(false));
+
   llvm::cl::opt<bool> MergeableTraps = llvm::cl::opt<bool>(
       "mergeable-traps",
       llvm::cl::desc("Enable cond_fail merging."));
@@ -654,7 +664,6 @@ getASTOverrideKind(const SILOptOptions &options) {
 
 int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
   INITIALIZE_LLVM();
-  llvm::setBugReportMsg(SWIFT_CRASH_BUG_REPORT_MESSAGE  "\n");
   llvm::EnablePrettyStackTraceOnSigInfoForThisThread();
 
   SILOptOptions options;
@@ -695,8 +704,8 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
     Invocation.setTargetTriple(options.Target);
   if (!options.ResourceDir.empty())
     Invocation.setRuntimeResourcePath(options.ResourceDir);
-  Invocation.getFrontendOptions().EnableLibraryEvolution
-    = options.EnableLibraryEvolution;
+  if (options.EnableLibraryEvolution)
+    Invocation.getLangOptions().enableFeature(Feature::LibraryEvolution);
   Invocation.getFrontendOptions().StrictImplicitModuleContext
     = options.StrictImplicitModuleContext;
 
@@ -753,14 +762,14 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
   }
 
   for (auto &featureName : options.UpcomingFeatures) {
-    auto feature = getUpcomingFeature(featureName);
+    auto feature = Feature::getUpcomingFeature(featureName);
     if (!feature) {
       llvm::errs() << "error: unknown upcoming feature "
                    << QuotedString(featureName) << "\n";
       exit(-1);
     }
 
-    if (auto firstVersion = getFeatureLanguageVersion(*feature)) {
+    if (auto firstVersion = feature->getLanguageVersion()) {
       if (Invocation.getLangOptions().isSwiftVersionAtLeast(*firstVersion)) {
         llvm::errs() << "error: upcoming feature " << QuotedString(featureName)
                      << " is already enabled as of Swift version "
@@ -772,7 +781,7 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
   }
 
   for (auto &featureName : options.ExperimentalFeatures) {
-    if (auto feature = getExperimentalFeature(featureName)) {
+    if (auto feature = Feature::getExperimentalFeature(featureName)) {
       Invocation.getLangOptions().enableFeature(*feature);
     } else {
       llvm::errs() << "error: unknown experimental feature "
@@ -785,8 +794,6 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
     options.EnableObjCInterop ? true :
     options.DisableObjCInterop ? false : llvm::Triple(options.Target).isOSDarwin();
 
-  Invocation.getLangOptions().enableFeature(Feature::LayoutPrespecialization);
-
   Invocation.getLangOptions().OptimizationRemarkPassedPattern =
       createOptRemarkRegex(options.PassRemarksPassed);
   Invocation.getLangOptions().OptimizationRemarkMissedPattern =
@@ -806,6 +813,8 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
   Invocation.getLangOptions().UnavailableDeclOptimizationMode =
       options.UnavailableDeclOptimization;
 
+  Invocation.computeAArch64TBIOptions();
+
   // Enable strict concurrency if we have the feature specified or if it was
   // specified via a command line option to sil-opt.
   if (Invocation.getLangOptions().hasFeature(Feature::StrictConcurrency)) {
@@ -821,7 +830,7 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
   }
 
   // If we have strict concurrency set as a feature and were told to turn off
-  // region based isolation... do so now.
+  // region-based isolation... do so now.
   if (Invocation.getLangOptions().hasFeature(Feature::StrictConcurrency)) {
     Invocation.getLangOptions().enableFeature(Feature::RegionBasedIsolation);
   }
@@ -887,7 +896,6 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
   SILOpts.EnableThrowsPrediction = options.EnableThrowsPrediction;
   SILOpts.EnableNoReturnCold = options.EnableNoReturnCold;
   SILOpts.IgnoreAlwaysInline = options.IgnoreAlwaysInline;
-  SILOpts.EnableOSSAModules = options.EnableOSSAModules;
   SILOpts.EnableSILOpaqueValues = options.EnableSILOpaqueValues;
   SILOpts.OSSACompleteLifetimes = options.EnableOSSACompleteLifetimes;
   SILOpts.OSSAVerifyComplete = options.EnableOSSAVerifyComplete;
@@ -898,7 +906,7 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
 
   // Unless overridden below, enabling copy propagation means enabling lexical
   // lifetimes.
-  if (SILOpts.CopyPropagation == CopyPropagationOption::On)
+  if (SILOpts.CopyPropagation >= CopyPropagationOption::Optimizing)
     SILOpts.LexicalLifetimes = LexicalLifetimesOption::On;
 
   // Unless overridden below, disable copy propagation means disabling lexical
@@ -918,6 +926,10 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
       options.EnablePackMetadataStackPromotion;
 
   SILOpts.EnableAddressDependencies = options.EnableAddressDependencies;
+  if (options.EnableCalleeAllocatedCoroAbi)
+    SILOpts.CoroutineAccessorsUseYieldOnce2 = true;
+  if (options.DisableCalleeAllocatedCoroAbi)
+    SILOpts.CoroutineAccessorsUseYieldOnce2 = false;
   SILOpts.MergeableTraps = options.MergeableTraps;
 
   if (options.OptModeFlag == OptimizationMode::NotSet) {
@@ -1069,7 +1081,6 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
     serializationOpts.OutputPath = OutputFile;
     serializationOpts.SerializeAllSIL = options.EmitSIB;
     serializationOpts.IsSIB = options.EmitSIB;
-    serializationOpts.IsOSSA = SILOpts.EnableOSSAModules;
 
     symbolgraphgen::SymbolGraphOptions symbolGraphOptions;
 
diff --git a/lib/DriverTool/swift_api_digester_main.cpp b/lib/DriverTool/swift_api_digester_main.cpp
index e90269541f93b..97a06d030a883 100644
--- a/lib/DriverTool/swift_api_digester_main.cpp
+++ b/lib/DriverTool/swift_api_digester_main.cpp
@@ -38,6 +38,7 @@
 #include "swift/Option/Options.h"
 #include "swift/Parse/ParseVersion.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/VirtualOutputBackends.h"
 #include "llvm/Support/raw_ostream.h"
 #include <functional>
@@ -852,8 +853,8 @@ class PrunePass : public MatchedNodeListener, public SDKTreeDiffPass {
       auto *LSub = dyn_cast<SDKNodeDeclSubscript>(Left);
       auto *RSub = dyn_cast<SDKNodeDeclSubscript>(Right);
       SequentialNodeMatcher(LSub->getChildren(), RSub->getChildren(), *this).match();
-#define ACCESSOR(ID)                                                          \
-      singleMatch(LSub->getAccessor(AccessorKind::ID),                        \
+#define ACCESSOR(ID, KEYWORD)                                                  \
+      singleMatch(LSub->getAccessor(AccessorKind::ID),                         \
                   RSub->getAccessor(AccessorKind::ID), *this);
 #include "swift/AST/AccessorKinds.def"
       break;
@@ -863,8 +864,8 @@ class PrunePass : public MatchedNodeListener, public SDKTreeDiffPass {
       auto *RVar = dyn_cast<SDKNodeDeclVar>(Right);
       // Match property type.
       singleMatch(LVar->getType(), RVar->getType(), *this);
-#define ACCESSOR(ID)                                                          \
-      singleMatch(LVar->getAccessor(AccessorKind::ID),                        \
+#define ACCESSOR(ID, KEYWORD)                                                  \
+      singleMatch(LVar->getAccessor(AccessorKind::ID),                         \
                   RVar->getAccessor(AccessorKind::ID), *this);
 #include "swift/AST/AccessorKinds.def"
       break;
@@ -2261,11 +2262,12 @@ class SwiftAPIDigesterInvocation {
   std::string BaselineSDK;
   std::string Triple;
   std::string SwiftVersion;
-  std::vector<std::string> CCSystemFrameworkPaths;
+  std::vector<std::string> SystemFrameworkPaths;
   std::vector<std::string> BaselineFrameworkPaths;
   std::vector<std::string> FrameworkPaths;
-  std::vector<std::string> BaselineModuleInputPaths;
-  std::vector<std::string> ModuleInputPaths;
+  std::vector<std::string> SystemModuleImportPaths;
+  std::vector<std::string> BaselineModuleImportPaths;
+  std::vector<std::string> ModuleImportPaths;
   std::string ModuleList;
   std::vector<std::string> ModuleNames;
   std::vector<std::string> PreferInterfaceForModules;
@@ -2362,11 +2364,13 @@ class SwiftAPIDigesterInvocation {
     BaselineSDK = ParsedArgs.getLastArgValue(OPT_bsdk).str();
     Triple = ParsedArgs.getLastArgValue(OPT_target).str();
     SwiftVersion = ParsedArgs.getLastArgValue(OPT_swift_version).str();
-    CCSystemFrameworkPaths = ParsedArgs.getAllArgValues(OPT_iframework);
+    SystemFrameworkPaths = ParsedArgs.getAllArgValues(OPT_Fsystem);
+    llvm::append_range(SystemFrameworkPaths, ParsedArgs.getAllArgValues(OPT_iframework));
     BaselineFrameworkPaths = ParsedArgs.getAllArgValues(OPT_BF);
     FrameworkPaths = ParsedArgs.getAllArgValues(OPT_F);
-    BaselineModuleInputPaths = ParsedArgs.getAllArgValues(OPT_BI);
-    ModuleInputPaths = ParsedArgs.getAllArgValues(OPT_I);
+    SystemModuleImportPaths = ParsedArgs.getAllArgValues(OPT_Isystem);
+    BaselineModuleImportPaths = ParsedArgs.getAllArgValues(OPT_BI);
+    ModuleImportPaths = ParsedArgs.getAllArgValues(OPT_I);
     ModuleList = ParsedArgs.getLastArgValue(OPT_module_list_file).str();
     ModuleNames = ParsedArgs.getAllArgValues(OPT_module);
     PreferInterfaceForModules =
@@ -2421,7 +2425,7 @@ class SwiftAPIDigesterInvocation {
   }
 
   bool hasBaselineInput() {
-    return !BaselineModuleInputPaths.empty() ||
+    return !BaselineModuleImportPaths.empty() ||
            !BaselineFrameworkPaths.empty() || !BaselineSDK.empty();
   }
 
@@ -2453,8 +2457,6 @@ class SwiftAPIDigesterInvocation {
     InitInvoke.getLangOptions().EnableObjCInterop =
         InitInvoke.getLangOptions().Target.isOSDarwin();
     InitInvoke.getClangImporterOptions().ModuleCachePath = ModuleCachePath;
-    // Module recovery issue shouldn't bring down the tool.
-    InitInvoke.getLangOptions().AllowDeserializingImplementationOnly = true;
 
     if (!SwiftVersion.empty()) {
       using version::Version;
@@ -2476,29 +2478,30 @@ class SwiftAPIDigesterInvocation {
       InitInvoke.setRuntimeResourcePath(ResourceDir);
     }
     std::vector<SearchPathOptions::SearchPath> FramePaths;
-    for (const auto &path : CCSystemFrameworkPaths) {
+    for (const auto &path : SystemFrameworkPaths) {
       FramePaths.push_back({path, /*isSystem=*/true});
     }
+    std::vector<SearchPathOptions::SearchPath> ImportPaths;
+    for (const auto &path : SystemModuleImportPaths) {
+      ImportPaths.push_back({path, /*isSystem=*/true});
+    }
     if (IsBaseline) {
       for (const auto &path : BaselineFrameworkPaths) {
         FramePaths.push_back({path, /*isSystem=*/false});
       }
-      std::vector<SearchPathOptions::SearchPath> ImportPaths;
-      for (const auto &path : BaselineModuleInputPaths) {
+      for (const auto &path : BaselineModuleImportPaths) {
         ImportPaths.push_back({path, /*isSystem=*/false});
       }
-      InitInvoke.setImportSearchPaths(ImportPaths);
     } else {
       for (const auto &path : FrameworkPaths) {
         FramePaths.push_back({path, /*isSystem=*/false});
       }
-      std::vector<SearchPathOptions::SearchPath> ImportPaths;
-      for (const auto &path : ModuleInputPaths) {
+      for (const auto &path : ModuleImportPaths) {
         ImportPaths.push_back({path, /*isSystem=*/false});
       }
-      InitInvoke.setImportSearchPaths(ImportPaths);
     }
     InitInvoke.setFrameworkSearchPaths(FramePaths);
+    InitInvoke.setImportSearchPaths(ImportPaths);
     if (!ModuleList.empty()) {
       if (readFileLineByLine(ModuleList, Modules))
         exit(1);
diff --git a/lib/DriverTool/swift_cache_tool_main.cpp b/lib/DriverTool/swift_cache_tool_main.cpp
index be1fe4ce157b3..d32519b0928a9 100644
--- a/lib/DriverTool/swift_cache_tool_main.cpp
+++ b/lib/DriverTool/swift_cache_tool_main.cpp
@@ -65,12 +65,13 @@ enum ID {
 #undef OPTION
 };
 
-#define PREFIX(NAME, VALUE)                                                    \
-  constexpr llvm::StringLiteral NAME##_init[] = VALUE;                         \
-  constexpr llvm::ArrayRef<llvm::StringLiteral> NAME(                          \
-      NAME##_init, std::size(NAME##_init) - 1);
+#define OPTTABLE_STR_TABLE_CODE
 #include "SwiftCacheToolOptions.inc"
-#undef PREFIX
+#undef OPTTABLE_STR_TABLE_CODE
+
+#define OPTTABLE_PREFIXES_TABLE_CODE
+#include "SwiftCacheToolOptions.inc"
+#undef OPTTABLE_PREFIXES_TABLE_CODE
 
 static const OptTable::Info InfoTable[] = {
 #define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
@@ -80,7 +81,8 @@ static const OptTable::Info InfoTable[] = {
 
 class CacheToolOptTable : public llvm::opt::GenericOptTable {
 public:
-  CacheToolOptTable() : GenericOptTable(InfoTable) {}
+  CacheToolOptTable()
+      : GenericOptTable(OptionStrTable, OptionPrefixesTable, InfoTable) {}
 };
 
 class SwiftCacheToolInvocation {
@@ -251,7 +253,8 @@ class SwiftCacheToolInvocation {
     auto BaseKey = Instance.getCompilerBaseKey();
     if (!BaseKey) {
       Instance.getDiags().diagnose(SourceLoc(), diag::error_cas,
-                                   "Base Key doesn't exist");
+                                   "query base cache key",
+                                   "base cache key doesn't exist");
       return std::nullopt;
     }
 
diff --git a/lib/DriverTool/swift_llvm_opt_main.cpp b/lib/DriverTool/swift_llvm_opt_main.cpp
index 00b97178dee56..6620418f3ddc9 100644
--- a/lib/DriverTool/swift_llvm_opt_main.cpp
+++ b/lib/DriverTool/swift_llvm_opt_main.cpp
@@ -135,7 +135,7 @@ getTargetMachine(llvm::Triple TheTriple, StringRef CPUStr,
   }
 
   return TheTarget->createTargetMachine(
-      TheTriple.getTriple(), CPUStr, FeaturesStr, targetOptions,
+      TheTriple, CPUStr, FeaturesStr, targetOptions,
       std::optional<llvm::Reloc::Model>(llvm::codegen::getExplicitRelocModel()),
       llvm::codegen::getExplicitCodeModel(), GetCodeGenOptLevel(options));
 }
@@ -174,7 +174,8 @@ int swift_llvm_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
 
   // If we are supposed to override the target triple, do so now.
   if (!options.TargetTriple.empty())
-    M->setTargetTriple(llvm::Triple::normalize(options.TargetTriple));
+    M->setTargetTriple(
+        llvm::Triple(llvm::Triple::normalize(options.TargetTriple)));
 
   // Figure out what stream we are supposed to write to...
   std::unique_ptr<llvm::ToolOutputFile> Out;
diff --git a/lib/DriverTool/swift_symbolgraph_extract_main.cpp b/lib/DriverTool/swift_symbolgraph_extract_main.cpp
index 1dedd9bb72202..6474dfa427f04 100644
--- a/lib/DriverTool/swift_symbolgraph_extract_main.cpp
+++ b/lib/DriverTool/swift_symbolgraph_extract_main.cpp
@@ -83,8 +83,7 @@ int swift_symbolgraph_extract_main(ArrayRef<const char *> Args,
   if (auto *A = ParsedArgs.getLastArg(OPT_target)) {
     Target = llvm::Triple(A->getValue());
   } else {
-    Diags.diagnose(SourceLoc(), diag::error_option_required, "-target");
-    return EXIT_FAILURE;
+    Target = llvm::Triple(llvm::sys::getDefaultTargetTriple());
   }
 
   std::string OutputDir;
@@ -141,7 +140,7 @@ int swift_symbolgraph_extract_main(ArrayRef<const char *> Args,
   Invocation.getLangOptions().EnableObjCInterop = Target.isOSDarwin();
   Invocation.getLangOptions().DebuggerSupport = true;
 
-  Invocation.getFrontendOptions().EnableLibraryEvolution = true;
+  Invocation.getLangOptions().enableFeature(Feature::LibraryEvolution);
 
   std::string ModuleCachePath = "";
   if (auto *A = ParsedArgs.getLastArg(OPT_module_cache_path)) {
@@ -203,7 +202,19 @@ int swift_symbolgraph_extract_main(ArrayRef<const char *> Args,
             .Default(AccessLevel::Public);
   }
 
-  Invocation.getLangOptions().setCxxInteropFromArgs(ParsedArgs, Diags);
+  if (auto *A = ParsedArgs.getLastArg(OPT_allow_availability_platforms,
+        OPT_block_availability_platforms)) {
+    llvm::SmallVector<StringRef> AvailabilityPlatforms;
+    StringRef(A->getValue())
+        .split(AvailabilityPlatforms, ',', /*MaxSplits*/ -1,
+               /*KeepEmpty*/ false);
+    Options.AvailabilityPlatforms = llvm::DenseSet<StringRef>(
+        AvailabilityPlatforms.begin(), AvailabilityPlatforms.end());
+    Options.AvailabilityIsBlockList = A->getOption().matches(OPT_block_availability_platforms);
+  }
+
+  Invocation.getLangOptions().setCxxInteropFromArgs(ParsedArgs, Diags,
+                                                    Invocation.getFrontendOptions());
 
   std::string InstanceSetupError;
   if (CI.setup(Invocation, InstanceSetupError)) {
diff --git a/lib/DriverTool/swift_synthesize_interface_main.cpp b/lib/DriverTool/swift_synthesize_interface_main.cpp
index aade905c153df..37861fb70ba8f 100644
--- a/lib/DriverTool/swift_synthesize_interface_main.cpp
+++ b/lib/DriverTool/swift_synthesize_interface_main.cpp
@@ -84,8 +84,7 @@ int swift_synthesize_interface_main(ArrayRef<const char *> Args,
   if (auto *A = ParsedArgs.getLastArg(OPT_target)) {
     Target = llvm::Triple(A->getValue());
   } else {
-    Diags.diagnose(SourceLoc(), diag::error_option_required, "-target");
-    return EXIT_FAILURE;
+    Target = llvm::Triple(llvm::sys::getDefaultTargetTriple());
   }
 
   std::string OutputFile;
@@ -133,7 +132,8 @@ int swift_synthesize_interface_main(ArrayRef<const char *> Args,
   Invocation.setImportSearchPaths(ImportSearchPaths);
 
   Invocation.getLangOptions().EnableObjCInterop = Target.isOSDarwin();
-  Invocation.getLangOptions().setCxxInteropFromArgs(ParsedArgs, Diags);
+  Invocation.getLangOptions().setCxxInteropFromArgs(ParsedArgs, Diags,
+                                                    Invocation.getFrontendOptions());
 
   std::string ModuleCachePath = "";
   if (auto *A = ParsedArgs.getLastArg(OPT_module_cache_path)) {
diff --git a/lib/Frontend/ArgsToFrontendOptionsConverter.cpp b/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
index 95d641dfb1dbc..fe16bf7f9af15 100644
--- a/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
+++ b/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
@@ -31,6 +31,7 @@
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/Option.h"
 #include "llvm/Support/Compression.h"
+#include "llvm/Support/PrefixMapper.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/LineIterator.h"
@@ -96,6 +97,7 @@ bool ArgsToFrontendOptionsConverter::convert(
   Opts.IndexSystemModules |= Args.hasArg(OPT_index_system_modules);
   Opts.IndexIgnoreStdlib |= Args.hasArg(OPT_index_ignore_stdlib);
   Opts.IndexIncludeLocals |= Args.hasArg(OPT_index_include_locals);
+  Opts.IndexStoreCompress |= Args.hasArg(OPT_index_store_compress);
   Opts.SerializeDebugInfoSIL |=
       Args.hasArg(OPT_experimental_serialize_debug_info);
 
@@ -106,16 +108,12 @@ bool ArgsToFrontendOptionsConverter::convert(
 
   Opts.EnableTesting |= Args.hasArg(OPT_enable_testing);
   Opts.EnablePrivateImports |= Args.hasArg(OPT_enable_private_imports);
-  Opts.EnableLibraryEvolution |= Args.hasArg(OPT_enable_library_evolution);
   Opts.FrontendParseableOutput |= Args.hasArg(OPT_frontend_parseable_output);
   Opts.ExplicitInterfaceBuild |= Args.hasArg(OPT_explicit_interface_module_build);
 
   Opts.EmitClangHeaderWithNonModularIncludes |=
       Args.hasArg(OPT_emit_clang_header_nonmodular_includes);
 
-  // FIXME: Remove this flag
-  Opts.EnableLibraryEvolution |= Args.hasArg(OPT_enable_resilience);
-
   Opts.EnableImplicitDynamic |= Args.hasArg(OPT_enable_implicit_dynamic);
 
   if (Args.hasArg(OPT_track_system_dependencies)) {
@@ -163,6 +161,9 @@ bool ArgsToFrontendOptionsConverter::convert(
   Opts.ParallelDependencyScan = Args.hasFlag(OPT_parallel_scan,
                                              OPT_no_parallel_scan,
                                              true);
+  Opts.GenReproducer |= Args.hasArg(OPT_gen_reproducer);
+  Opts.GenReproducerDir = Args.getLastArgValue(OPT_gen_reproducer_dir);
+
   if (const Arg *A = Args.getLastArg(OPT_dependency_scan_cache_path)) {
     Opts.SerializedDependencyScannerCachePath = A->getValue();
   }
@@ -193,7 +194,11 @@ bool ArgsToFrontendOptionsConverter::convert(
   computeDebugTimeOptions();
   computeTBDOptions();
 
-  Opts.DumpClangLookupTables |= Args.hasArg(OPT_dump_clang_lookup_tables);
+  Opts.CompilerDebuggingOpts.DumpAvailabilityScopes |=
+      Args.hasArg(OPT_dump_availability_scopes);
+
+  Opts.CompilerDebuggingOpts.DumpClangLookupTables |=
+      Args.hasArg(OPT_dump_clang_lookup_tables);
 
   Opts.CheckOnoneSupportCompleteness = Args.hasArg(OPT_check_onone_completeness);
 
@@ -206,6 +211,14 @@ bool ArgsToFrontendOptionsConverter::convert(
     Opts.PrintTargetInfo = true;
   }
 
+  if (Args.hasArg(OPT_print_static_build_config)) {
+    Opts.PrintBuildConfig = true;
+  }
+
+  if (Args.hasArg(OPT_print_supported_features)) {
+    Opts.PrintSupportedFeatures = true;
+  }
+
   if (const Arg *A = Args.getLastArg(OPT_verify_generic_signatures)) {
     Opts.VerifyGenericSignaturesInModule = A->getValue();
   }
@@ -311,7 +324,9 @@ bool ArgsToFrontendOptionsConverter::convert(
     return true;
 
   Opts.DeterministicCheck |= Args.hasArg(OPT_enable_deterministic_check);
-  Opts.CacheReplayPrefixMap = Args.getAllArgValues(OPT_cache_replay_prefix_map);
+  for (const Arg *A : Args.filtered(OPT_cache_replay_prefix_map)) {
+    Opts.CacheReplayPrefixMap.push_back({A->getValue(0), A->getValue(1)});
+  }
 
   if (FrontendOptions::doesActionGenerateIR(Opts.RequestedAction)) {
     if (Args.hasArg(OPT_experimental_skip_non_inlinable_function_bodies) ||
@@ -358,9 +373,6 @@ bool ArgsToFrontendOptionsConverter::convert(
   if (!computeModuleAliases())
     return true;
 
-  if (const Arg *A = Args.getLastArg(OPT_access_notes_path))
-    Opts.AccessNotesPath = A->getValue();
-
   if (const Arg *A = Args.getLastArg(OPT_serialize_debugging_options,
                                      OPT_no_serialize_debugging_options)) {
     Opts.SerializeOptionsForDebugging =
@@ -461,10 +473,11 @@ void ArgsToFrontendOptionsConverter::handleDebugCrashGroupArguments() {
 void ArgsToFrontendOptionsConverter::computePrintStatsOptions() {
   using namespace options;
   Opts.PrintStats |= Args.hasArg(OPT_print_stats);
-  Opts.PrintClangStats |= Args.hasArg(OPT_print_clang_stats);
+  Opts.CompilerDebuggingOpts.PrintClangStats |=
+      Args.hasArg(OPT_print_clang_stats);
   Opts.PrintZeroStats |= Args.hasArg(OPT_print_zero_stats);
 #if defined(NDEBUG) && !LLVM_ENABLE_STATS
-  if (Opts.PrintStats || Opts.PrintClangStats)
+  if (Opts.PrintStats || Opts.CompilerDebuggingOpts.PrintClangStats)
     Diags.diagnose(SourceLoc(), diag::stats_disabled);
 #endif
 }
@@ -571,6 +584,7 @@ bool ArgsToFrontendOptionsConverter::computeAvailabilityDomains() {
 
   for (const Arg *A :
        Args.filtered_reverse(OPT_define_enabled_availability_domain,
+                             OPT_define_always_enabled_availability_domain,
                              OPT_define_disabled_availability_domain,
                              OPT_define_dynamic_availability_domain)) {
     std::string domain = A->getValue();
@@ -587,6 +601,8 @@ bool ArgsToFrontendOptionsConverter::computeAvailabilityDomains() {
     auto &option = A->getOption();
     if (option.matches(OPT_define_enabled_availability_domain))
       Opts.AvailabilityDomains.EnabledDomains.emplace_back(domain);
+    if (option.matches(OPT_define_always_enabled_availability_domain))
+      Opts.AvailabilityDomains.AlwaysEnabledDomains.emplace_back(domain);
     else if (option.matches(OPT_define_disabled_availability_domain))
       Opts.AvailabilityDomains.DisabledDomains.emplace_back(domain);
     else if (option.matches(OPT_define_dynamic_availability_domain))
@@ -655,8 +671,6 @@ ArgsToFrontendOptionsConverter::determineRequestedAction(const ArgList &args) {
     return FrontendOptions::ActionType::MergeModules;
   if (Opt.matches(OPT_dump_scope_maps))
     return FrontendOptions::ActionType::DumpScopeMaps;
-  if (Opt.matches(OPT_dump_availability_scopes))
-    return FrontendOptions::ActionType::DumpAvailabilityScopes;
   if (Opt.matches(OPT_dump_interface_hash))
     return FrontendOptions::ActionType::DumpInterfaceHash;
   if (Opt.matches(OPT_dump_type_info))
@@ -678,8 +692,8 @@ ArgsToFrontendOptionsConverter::determineRequestedAction(const ArgList &args) {
     return FrontendOptions::ActionType::CompileModuleFromInterface;
   if (Opt.matches(OPT_typecheck_module_from_interface))
     return FrontendOptions::ActionType::TypecheckModuleFromInterface;
-  if (Opt.matches(OPT_emit_supported_features))
-    return FrontendOptions::ActionType::PrintFeature;
+  if (Opt.matches(OPT_emit_supported_arguments))
+    return FrontendOptions::ActionType::PrintArguments;
   llvm_unreachable("Unhandled mode option");
 }
 
@@ -900,18 +914,40 @@ static inline bool isPCHFilenameExtension(StringRef path) {
 
 void ArgsToFrontendOptionsConverter::computeImportObjCHeaderOptions() {
   using namespace options;
-  if (const Arg *A = Args.getLastArgNoClaim(OPT_import_objc_header)) {
-    // Legacy support for passing PCH file through `-import-objc-header`.
+  bool hadNormalBridgingHeader = false;
+  if (const Arg *A = Args.getLastArgNoClaim(
+          OPT_import_bridging_header,
+          OPT_internal_import_bridging_header)) {
+    // Legacy support for passing PCH file through `-import-bridging-header`.
     if (isPCHFilenameExtension(A->getValue()))
       Opts.ImplicitObjCPCHPath = A->getValue();
     else
       Opts.ImplicitObjCHeaderPath = A->getValue();
-    // If `-import-object-header` is used, it means the module has a direct
+    // If `-import-bridging-header` is used, it means the module has a direct
     // bridging header dependency and it can be serialized into binary module.
     Opts.ModuleHasBridgingHeader |= true;
+
+    Opts.ImportHeaderAsInternal =
+        A->getOption().getID() == OPT_internal_import_bridging_header;
+
+    hadNormalBridgingHeader = true;
   }
-  if (const Arg *A = Args.getLastArgNoClaim(OPT_import_pch))
+  if (const Arg *A = Args.getLastArgNoClaim(OPT_import_pch,
+                                            OPT_internal_import_pch)) {
     Opts.ImplicitObjCPCHPath = A->getValue();
+
+    bool importAsInternal = A->getOption().getID() == OPT_internal_import_pch;
+
+    /// Don't let the bridging-header and precompiled-header options differ in
+    /// whether they are treated as internal or public imports.
+    if (hadNormalBridgingHeader &&
+        importAsInternal != Opts.ImportHeaderAsInternal) {
+      Diags.diagnose(SourceLoc(),
+                     diag::bridging_header_and_pch_internal_mismatch);
+    }
+
+    Opts.ImportHeaderAsInternal = importAsInternal;
+  }
 }
 void ArgsToFrontendOptionsConverter::
 computeImplicitImportModuleNames(OptSpecifier id, bool isTestable) {
@@ -980,13 +1016,12 @@ bool ModuleAliasesConverter::computeModuleAliases(std::vector<std::string> args,
 
       // First, add the real name as a key to prevent it from being
       // used as an alias
-      if (!options.ModuleAliasMap.insert({rhs, StringRef()}).second) {
+      if (!options.ModuleAliasMap.insert({rhs, ""}).second) {
         diags.diagnose(SourceLoc(), diag::error_module_alias_duplicate, rhs);
         return false;
       }
       // Next, add the alias as a key and the real name as a value to the map
-      auto underlyingName = options.ModuleAliasMap.find(rhs)->first();
-      if (!options.ModuleAliasMap.insert({lhs, underlyingName}).second) {
+      if (!options.ModuleAliasMap.insert({lhs, rhs.str()}).second) {
         diags.diagnose(SourceLoc(), diag::error_module_alias_duplicate, lhs);
         return false;
       }
diff --git a/lib/Frontend/ArgsToFrontendOutputsConverter.cpp b/lib/Frontend/ArgsToFrontendOutputsConverter.cpp
index ab95d58abd27f..31cfd92649ebb 100644
--- a/lib/Frontend/ArgsToFrontendOutputsConverter.cpp
+++ b/lib/Frontend/ArgsToFrontendOutputsConverter.cpp
@@ -298,6 +298,47 @@ SupplementaryOutputPathsComputer::computeOutputPaths() const {
       });
   if (hadError)
     return std::nullopt;
+
+  // In WMO mode compute supplementary output paths for optimization record
+  // data (opt-remarks). We need one path per LLVMModule that will be created as
+  // part of wmo.
+  if (!InputsAndOutputs.hasPrimaryInputs()) {
+    unsigned i = 0;
+    InputsAndOutputs.forEachInput([&](const InputFile &input) -> bool {
+      // First input is already computed.
+      if (InputsAndOutputs.firstInput().getFileName() == input.getFileName()) {
+        ++i;
+        return false;
+      }
+      SupplementaryOutputPaths outputs;
+
+      // Compute auxiliar opt record paths.
+      if(OutputFiles.size() > 1) {
+        StringRef defaultSupplementaryOutputPathExcludingExtension =
+            deriveDefaultSupplementaryOutputPathExcludingExtension(
+              OutputFiles[i], input);
+
+        auto YAMLOptRecordPath = determineSupplementaryOutputFilename(
+          options::OPT_save_optimization_record,
+          "",
+          file_types::TY_YAMLOptRecord, "",
+          defaultSupplementaryOutputPathExcludingExtension, true);
+        outputs.YAMLOptRecordPath = YAMLOptRecordPath;
+
+        auto bitstreamOptRecordPath = determineSupplementaryOutputFilename(
+          options::OPT_save_optimization_record,
+          "",
+          file_types::TY_BitstreamOptRecord, "",
+          defaultSupplementaryOutputPathExcludingExtension, true);
+
+        outputs.BitstreamOptRecordPath = bitstreamOptRecordPath;
+      }
+
+      outputPaths.emplace_back(std::move(outputs));
+      ++i;
+      return false;
+    });
+  }
   return outputPaths;
 }
 
@@ -317,8 +358,6 @@ SupplementaryOutputPathsComputer::getSupplementaryOutputPathsFromArguments()
       options::OPT_emit_reference_dependencies_path);
   auto serializedDiagnostics = getSupplementaryFilenamesFromArguments(
       options::OPT_serialize_diagnostics_path);
-  auto fixItsOutput = getSupplementaryFilenamesFromArguments(
-      options::OPT_emit_fixits_path);
   auto loadedModuleTrace = getSupplementaryFilenamesFromArguments(
       options::OPT_emit_loaded_module_trace_path);
   auto TBD = getSupplementaryFilenamesFromArguments(options::OPT_emit_tbd_path);
@@ -343,7 +382,7 @@ SupplementaryOutputPathsComputer::getSupplementaryOutputPathsFromArguments()
       options::OPT_save_optimization_record_path);
   if (!clangHeaderOutput || !moduleOutput || !moduleDocOutput ||
       !dependenciesFile || !referenceDependenciesFile ||
-      !serializedDiagnostics || !fixItsOutput || !loadedModuleTrace || !TBD ||
+      !serializedDiagnostics || !loadedModuleTrace || !TBD ||
       !moduleInterfaceOutput || !privateModuleInterfaceOutput || !packageModuleInterfaceOutput ||
       !moduleSourceInfoOutput || !moduleSummaryOutput || !abiDescriptorOutput ||
       !moduleSemanticInfoOutput || !optRecordOutput) {
@@ -361,7 +400,6 @@ SupplementaryOutputPathsComputer::getSupplementaryOutputPathsFromArguments()
     sop.DependenciesFilePath = (*dependenciesFile)[i];
     sop.ReferenceDependenciesFilePath = (*referenceDependenciesFile)[i];
     sop.SerializedDiagnosticsPath = (*serializedDiagnostics)[i];
-    sop.FixItsOutputPath = (*fixItsOutput)[i];
     sop.LoadedModuleTracePath = (*loadedModuleTrace)[i];
     sop.TBDPath = (*TBD)[i];
     sop.ModuleInterfaceOutputPath = (*moduleInterfaceOutput)[i];
@@ -435,7 +473,6 @@ static bool shouldEmitFineModuleTrace(FrontendOptions::ActionType action) {
   case swift::FrontendOptions::ActionType::PrintAST:
   case swift::FrontendOptions::ActionType::PrintASTDecl:
   case swift::FrontendOptions::ActionType::DumpScopeMaps:
-  case swift::FrontendOptions::ActionType::DumpAvailabilityScopes:
   case swift::FrontendOptions::ActionType::EmitImportedModules:
   case swift::FrontendOptions::ActionType::EmitPCH:
   case swift::FrontendOptions::ActionType::EmitModuleOnly:
@@ -451,7 +488,7 @@ static bool shouldEmitFineModuleTrace(FrontendOptions::ActionType action) {
   case swift::FrontendOptions::ActionType::DumpPCM:
   case swift::FrontendOptions::ActionType::ScanDependencies:
   case swift::FrontendOptions::ActionType::PrintVersion:
-  case swift::FrontendOptions::ActionType::PrintFeature:
+  case swift::FrontendOptions::ActionType::PrintArguments:
     return false;
   }
 }
@@ -568,11 +605,11 @@ SupplementaryOutputPathsComputer::computeOutputPathsForOneInput(
       defaultSupplementaryOutputPathExcludingExtension);
 
   auto YAMLOptRecordPath = determineSupplementaryOutputFilename(
-      OPT_save_optimization_record_path, pathsFromArguments.YAMLOptRecordPath,
+      OPT_save_optimization_record, pathsFromArguments.YAMLOptRecordPath,
       file_types::TY_YAMLOptRecord, "",
       defaultSupplementaryOutputPathExcludingExtension);
   auto bitstreamOptRecordPath = determineSupplementaryOutputFilename(
-      OPT_save_optimization_record_path, pathsFromArguments.BitstreamOptRecordPath,
+      OPT_save_optimization_record, pathsFromArguments.BitstreamOptRecordPath,
       file_types::TY_BitstreamOptRecord, "",
       defaultSupplementaryOutputPathExcludingExtension);
 
@@ -618,21 +655,45 @@ std::string
 SupplementaryOutputPathsComputer::determineSupplementaryOutputFilename(
     options::ID emitOpt, std::string pathFromArguments, file_types::ID type,
     StringRef mainOutputIfUsable,
-    StringRef defaultSupplementaryOutputPathExcludingExtension) const {
+    StringRef defaultSupplementaryOutputPathExcludingExtension,
+    bool forceDefaultSupplementaryOutputPathExcludingExtension) const {
+
+  auto hasEmitOptArg = [&] () -> bool {
+    if (Args.hasArg(emitOpt))
+      return true;
+    if (emitOpt == options::OPT_save_optimization_record &&
+        Args.hasArg(options::OPT_save_optimization_record_EQ))
+      return true;
+    return false;
+  };
+
+  auto computeDefaultSupplementaryOutputPathExcludingExtension =
+    [&] () -> std::string {
+      llvm::SmallString<128> path(
+        defaultSupplementaryOutputPathExcludingExtension);
+
+      llvm::sys::path::replace_extension(path, file_types::getExtension(type));
+      return path.str().str();
+    };
+
+  if (forceDefaultSupplementaryOutputPathExcludingExtension) {
+    if (!hasEmitOptArg()) {
+      return std::string();
+    }
+    return computeDefaultSupplementaryOutputPathExcludingExtension();
+  }
 
   if (!pathFromArguments.empty())
     return pathFromArguments;
 
-  if (!Args.hasArg(emitOpt))
+  if (!hasEmitOptArg())
     return std::string();
 
   if (!mainOutputIfUsable.empty()) {
     return mainOutputIfUsable.str();
   }
 
-  llvm::SmallString<128> path(defaultSupplementaryOutputPathExcludingExtension);
-  llvm::sys::path::replace_extension(path, file_types::getExtension(type));
-  return path.str().str();
+  return computeDefaultSupplementaryOutputPathExcludingExtension();
 }
 
 void SupplementaryOutputPathsComputer::deriveModulePathParameters(
diff --git a/lib/Frontend/ArgsToFrontendOutputsConverter.h b/lib/Frontend/ArgsToFrontendOutputsConverter.h
index 990b4010e6c36..220ce41f6e5a0 100644
--- a/lib/Frontend/ArgsToFrontendOutputsConverter.h
+++ b/lib/Frontend/ArgsToFrontendOutputsConverter.h
@@ -180,7 +180,8 @@ class SupplementaryOutputPathsComputer {
   std::string determineSupplementaryOutputFilename(
       options::ID emitOpt, std::string pathFromArgumentsOrFilelists,
       file_types::ID type, StringRef mainOutputIfUsable,
-      StringRef defaultSupplementaryOutputPathExcludingExtension) const;
+      StringRef defaultSupplementaryOutputPathExcludingExtension,
+      bool forceDefaultSupplementaryOutputPathExcludingExtension = false) const;
 
   void deriveModulePathParameters(StringRef mainOutputFile,
                                   options::ID &emitOption,
diff --git a/lib/Frontend/CASOutputBackends.cpp b/lib/Frontend/CASOutputBackends.cpp
index 3abed721d9afe..968ced016bad8 100644
--- a/lib/Frontend/CASOutputBackends.cpp
+++ b/lib/Frontend/CASOutputBackends.cpp
@@ -22,6 +22,7 @@
 #include "llvm/CAS/HierarchicalTreeBuilder.h"
 #include "llvm/CAS/ObjectStore.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/Mutex.h"
 #include <optional>
 
 #define DEBUG_TYPE "swift-cas-backend"
@@ -77,11 +78,11 @@ class SwiftCASOutputBackend::Implementation {
             (void)Shortened;
             std::optional<ObjectRef> PathRef;
             if (Error E =
-                    CAS.storeFromString(std::nullopt, Path).moveInto(PathRef))
+                    CAS.storeFromString(/*Refs*/ {}, Path).moveInto(PathRef))
               return E;
             std::optional<ObjectRef> BytesRef;
             if (Error E =
-                    CAS.storeFromString(std::nullopt, Bytes).moveInto(BytesRef))
+                    CAS.storeFromString(/*Refs*/ {}, Bytes).moveInto(BytesRef))
               return E;
             auto Ref = CAS.store({*PathRef, *BytesRef}, {});
             if (!Ref)
@@ -112,6 +113,9 @@ class SwiftCASOutputBackend::Implementation {
   Error storeImpl(StringRef Path, StringRef Bytes, unsigned InputIndex,
                   file_types::ID OutputKind);
 
+  // Return true if all the outputs are produced for the given index.
+  bool addProducedOutput(unsigned InputIndex, file_types::ID OutputKind,
+                         ObjectRef BytesRef);
   Error finalizeCacheKeysFor(unsigned InputIndex);
 
 private:
@@ -123,6 +127,9 @@ class SwiftCASOutputBackend::Implementation {
   const FrontendOptions &Opts;
   FrontendOptions::ActionType Action;
 
+  // Lock for updating output file status.
+  llvm::sys::SmartMutex<true> OutputLock;
+
   // Map from output path to the input index and output kind.
   StringMap<std::pair<unsigned, file_types::ID>> OutputToInputMap;
 
@@ -197,8 +204,10 @@ Error SwiftCASOutputBackend::storeMCCASObjectID(StringRef OutputFilename,
     return createStringError("Invalid CASID: " + ID.toString() +
                              ". No associated ObjectRef found!");
 
-  Impl.OutputRefs[InputIndex].insert({file_types::TY_Object, *MCRef});
-  return Impl.finalizeCacheKeysFor(InputIndex);
+  if (Impl.addProducedOutput(InputIndex, file_types::TY_Object, *MCRef))
+    return Impl.finalizeCacheKeysFor(InputIndex);
+
+  return Error::success();
 }
 
 void SwiftCASOutputBackend::Implementation::initBackend(
@@ -218,6 +227,12 @@ void SwiftCASOutputBackend::Implementation::initBackend(
     Input.getPrimarySpecificPaths()
         .SupplementaryOutputs.forEachSetOutputAndType(
             [&](const std::string &Out, file_types::ID ID) {
+              // FIXME: Opt Remarks are not setup correctly to be cached and
+              // didn't go through the output backend. Do not cache them.
+              if (ID == file_types::ID::TY_YAMLOptRecord ||
+                  ID == file_types::ID::TY_BitstreamOptRecord)
+                return;
+
               if (!file_types::isProducedFromDiagnostics(ID))
                 OutputToInputMap.insert({Out, {Index, ID}});
             });
@@ -241,7 +256,7 @@ Error SwiftCASOutputBackend::Implementation::storeImpl(
     StringRef Path, StringRef Bytes, unsigned InputIndex,
     file_types::ID OutputKind) {
   std::optional<ObjectRef> BytesRef;
-  if (Error E = CAS.storeFromString(std::nullopt, Bytes).moveInto(BytesRef))
+  if (Error E = CAS.storeFromString(/*Refs*/ {}, Bytes).moveInto(BytesRef))
     return E;
 
   LLVM_DEBUG(llvm::dbgs() << "DEBUG: producing CAS output of type \'"
@@ -249,23 +264,29 @@ Error SwiftCASOutputBackend::Implementation::storeImpl(
                           << "\' for input \'" << InputIndex << "\': \'"
                           << CAS.getID(*BytesRef).toString() << "\'\n";);
 
-  OutputRefs[InputIndex].insert({OutputKind, *BytesRef});
+  if (addProducedOutput(InputIndex, OutputKind, *BytesRef))
+    return finalizeCacheKeysFor(InputIndex);
+  return Error::success();
+}
+
+bool SwiftCASOutputBackend::Implementation::addProducedOutput(
+    unsigned InputIndex, file_types::ID OutputKind,
+    ObjectRef BytesRef) {
+  llvm::sys::SmartScopedLock<true> LockOutput(OutputLock);
+  auto &ProducedOutputs = OutputRefs[InputIndex];
+  ProducedOutputs.insert({OutputKind, BytesRef});
 
-  return finalizeCacheKeysFor(InputIndex);
+  return llvm::all_of(OutputToInputMap, [&](auto &E) {
+    return (E.second.first != InputIndex ||
+            ProducedOutputs.count(E.second.second));
+  });
 }
 
 Error SwiftCASOutputBackend::Implementation::finalizeCacheKeysFor(
     unsigned InputIndex) {
-  auto ProducedOutputs = OutputRefs[InputIndex];
+  const auto &ProducedOutputs = OutputRefs[InputIndex];
   assert(!ProducedOutputs.empty() && "Expect outputs for this input");
 
-  // If not all outputs for the input are emitted, return.
-  if (!llvm::all_of(OutputToInputMap, [&](auto &E) {
-        return (E.second.first != InputIndex ||
-                ProducedOutputs.count(E.second.second));
-      }))
-    return Error::success();
-
   std::vector<std::pair<file_types::ID, ObjectRef>> OutputsForInput;
   llvm::for_each(ProducedOutputs, [&OutputsForInput](auto E) {
     OutputsForInput.emplace_back(E.first, E.second);
diff --git a/lib/Frontend/CachedDiagnostics.cpp b/lib/Frontend/CachedDiagnostics.cpp
index b1b9c48780d63..d87963c2a72eb 100644
--- a/lib/Frontend/CachedDiagnostics.cpp
+++ b/lib/Frontend/CachedDiagnostics.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -18,7 +18,9 @@
 
 #include "swift/AST/DiagnosticBridge.h"
 #include "swift/AST/DiagnosticConsumer.h"
+#include "swift/AST/DiagnosticsCommon.h"
 #include "swift/AST/DiagnosticsFrontend.h"
+#include "swift/AST/DiagnosticsSema.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/SourceManager.h"
 #include "swift/Frontend/Frontend.h"
@@ -34,7 +36,6 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/PrefixMapper.h"
-#include "llvm/Support/SMLoc.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/Support/raw_ostream.h"
@@ -338,7 +339,8 @@ unsigned DiagnosticSerializer::getFileIDFromBufferID(SourceManager &SM,
 
   StringRef FileContent = Buf.Buffer->getBuffer();
   SerializedFile File = {Filename.str(),
-                         convertSourceLoc(SM, SourceLoc(Buf.IncludeLoc)),
+                         convertSourceLoc(SM, SourceLoc::getFromPointer(
+                                                  Buf.IncludeLoc.getPointer())),
                          {},
                          IsFileBacked ? "" : FileContent};
 
@@ -499,8 +501,7 @@ DiagnosticSerializer::deserializeSourceLoc(const SerializedSourceLoc &Loc) {
     return createDeserializationError("File doesn't exist in SourceManager");
   auto &Info = SrcMgr.getLLVMSourceMgr().getBufferInfo(BufID->second);
   const char *Buffer = Info.Buffer->getBufferStart();
-  llvm::SMLoc SL = llvm::SMLoc::getFromPointer(Buffer + Loc.Offset);
-  return SourceLoc(SL);
+  return SourceLoc::getFromPointer(Buffer + Loc.Offset);
 }
 
 llvm::Expected<CharSourceRange> DiagnosticSerializer::deserializeSourceRange(
@@ -719,7 +720,7 @@ class CachingDiagnosticsProcessor::Implementation
             Instance.getInvocation().getFrontendOptions().InputsAndOutputs),
         Diags(Instance.getDiags()), CAS(*Instance.getSharedCASInstance()) {
     SmallVector<llvm::MappedPrefix, 4> Prefixes;
-    llvm::MappedPrefix::transformJoinedIfValid(
+    llvm::MappedPrefix::transformPairs(
         Instance.getInvocation().getFrontendOptions().CacheReplayPrefixMap,
         Prefixes);
     Mapper.addRange(Prefixes);
@@ -755,6 +756,13 @@ class CachingDiagnosticsProcessor::Implementation
     auto &Serializer = getSerializer();
     assert(SM.getFileSystem() == Serializer.getSourceMgr().getFileSystem() &&
            "Caching for a different file system");
+
+    // Bypass the caching.
+    if (BypassDiagIDs.count(Info.ID)) {
+      for (auto *Diag : OrigConsumers)
+        Diag->handleDiagnostic(Serializer.getSourceMgr(), Info);
+      return;
+    }
     Serializer.handleDiagnostic(SM, Info, [&](const DiagnosticInfo &Info) {
       for (auto *Diag : OrigConsumers)
         Diag->handleDiagnostic(Serializer.getSourceMgr(), Info);
@@ -809,6 +817,8 @@ class CachingDiagnosticsProcessor::Implementation
   // Processor/Serializer alive until then.
   std::unique_ptr<DiagnosticSerializer> Serializer;
 
+  const llvm::SmallDenseSet<DiagID> BypassDiagIDs = {diag::macro_loaded.ID};
+
   SourceManager &InstanceSourceMgr;
   const FrontendInputsAndOutputs &InAndOut;
   DiagnosticEngine &Diags;
@@ -857,7 +867,7 @@ CachingDiagnosticsProcessor::CachingDiagnosticsProcessor(
 
     if (Err) {
       Instance.getDiags().diagnose(SourceLoc(), diag::error_cas,
-                                   toString(std::move(Err)));
+                                   "storing outputs", toString(std::move(Err)));
       return true;
     }
 
diff --git a/lib/Frontend/CachingUtils.cpp b/lib/Frontend/CachingUtils.cpp
index 917eb1153427a..151db67c8f282 100644
--- a/lib/Frontend/CachingUtils.cpp
+++ b/lib/Frontend/CachingUtils.cpp
@@ -340,7 +340,7 @@ bool replayCachedCompilerOutputs(
         createCompileJobCacheKeyForOutput(CAS, BaseKey, InputIndex);
 
     if (!OutputKey) {
-      Diag.diagnose(SourceLoc(), diag::error_cas,
+      Diag.diagnose(SourceLoc(), diag::error_cas, "output cache key creation",
                     toString(OutputKey.takeError()));
       return std::nullopt;
     }
@@ -348,7 +348,7 @@ bool replayCachedCompilerOutputs(
     auto OutID = CAS.getID(*OutputKey);
     auto OutputRef = lookupCacheKey(CAS, Cache, *OutputKey);
     if (!OutputRef) {
-      Diag.diagnose(SourceLoc(), diag::error_cas,
+      Diag.diagnose(SourceLoc(), diag::error_cas, "cache key lookup",
                     toString(OutputRef.takeError()));
       return std::nullopt;
     }
@@ -403,20 +403,24 @@ std::unique_ptr<llvm::MemoryBuffer>
 loadCachedCompileResultFromCacheKey(ObjectStore &CAS, ActionCache &Cache,
                                     DiagnosticEngine &Diag, StringRef CacheKey,
                                     file_types::ID Kind, StringRef Filename) {
-  auto failure = [&](Error Err) {
-    Diag.diagnose(SourceLoc(), diag::error_cas, toString(std::move(Err)));
+  auto failure = [&](StringRef Stage, Error Err) {
+    Diag.diagnose(SourceLoc(), diag::error_cas, Stage,
+                  toString(std::move(Err)));
     return nullptr;
   };
   auto ID = CAS.parseID(CacheKey);
-  if (!ID)
-    return failure(ID.takeError());
+  if (!ID) {
+    Diag.diagnose(SourceLoc(), diag::error_invalid_cas_id, CacheKey,
+                  toString(ID.takeError()));
+    return nullptr;
+  }
   auto Ref = CAS.getReference(*ID);
   if (!Ref)
     return nullptr;
 
   auto OutputRef = lookupCacheKey(CAS, Cache, *Ref);
   if (!OutputRef)
-    return failure(OutputRef.takeError());
+    return failure("lookup cache key", OutputRef.takeError());
 
   if (!*OutputRef)
     return nullptr;
@@ -435,7 +439,7 @@ loadCachedCompileResultFromCacheKey(ObjectStore &CAS, ActionCache &Cache,
             Buffer = Proxy->getMemoryBuffer(Filename);
             return Error::success();
           }))
-    return failure(std::move(Err));
+    return failure("loading cached results", std::move(Err));
 
   return Buffer;
 }
@@ -445,53 +449,14 @@ static llvm::Error createCASObjectNotFoundError(const llvm::cas::CASID &ID) {
                            "CASID missing from Object Store " + ID.toString());
 }
 
-static Expected<ObjectRef> mergeCASFileSystem(ObjectStore &CAS,
-                                              ArrayRef<std::string> FSRoots) {
-  llvm::cas::HierarchicalTreeBuilder Builder;
-  for (auto &Root : FSRoots) {
-    auto ID = CAS.parseID(Root);
-    if (!ID)
-      return ID.takeError();
-
-    auto Ref = CAS.getReference(*ID);
-    if (!Ref)
-      return createCASObjectNotFoundError(*ID);
-    Builder.pushTreeContent(*Ref, "");
-  }
-
-  auto NewRoot = Builder.create(CAS);
-  if (!NewRoot)
-    return NewRoot.takeError();
-
-  return NewRoot->getRef();
-}
-
 Expected<IntrusiveRefCntPtr<vfs::FileSystem>>
-createCASFileSystem(ObjectStore &CAS, ArrayRef<std::string> FSRoots,
-                    ArrayRef<std::string> IncludeTrees,
-                    ArrayRef<std::string> IncludeTreeFileList) {
-  assert(!FSRoots.empty() || !IncludeTrees.empty() ||
+createCASFileSystem(ObjectStore &CAS, const std::string &IncludeTree,
+                    const std::string &IncludeTreeFileList) {
+  assert(!IncludeTree.empty() ||
          !IncludeTreeFileList.empty() && "no root ID provided");
-  if (FSRoots.size() == 1 && IncludeTrees.empty()) {
-    auto ID = CAS.parseID(FSRoots.front());
-    if (!ID)
-      return ID.takeError();
-    return createCASFileSystem(CAS, *ID);
-  }
-
-  auto NewRoot = mergeCASFileSystem(CAS, FSRoots);
-  if (!NewRoot)
-    return NewRoot.takeError();
-
-  auto FS = createCASFileSystem(CAS, CAS.getID(*NewRoot));
-  if (!FS)
-    return FS.takeError();
 
-  auto CASFS = makeIntrusiveRefCnt<vfs::OverlayFileSystem>(std::move(*FS));
-  std::vector<clang::cas::IncludeTree::FileList::FileEntry> Files;
-  // Push all Include File System onto overlay.
-  for (auto &Tree : IncludeTrees) {
-    auto ID = CAS.parseID(Tree);
+  if (!IncludeTree.empty()) {
+    auto ID = CAS.parseID(IncludeTree);
     if (!ID)
       return ID.takeError();
 
@@ -506,47 +471,33 @@ createCASFileSystem(ObjectStore &CAS, ArrayRef<std::string> FSRoots,
     if (!ITF)
       return ITF.takeError();
 
-    auto Err = ITF->forEachFile(
-        [&](clang::cas::IncludeTree::File File,
-            clang::cas::IncludeTree::FileList::FileSizeTy Size) -> llvm::Error {
-          Files.push_back({File.getRef(), Size});
-          return llvm::Error::success();
-        });
+    auto ITFS = clang::cas::createIncludeTreeFileSystem(*ITF);
+    if (!ITFS)
+      return ITFS.takeError();
 
-    if (Err)
-      return std::move(Err);
+    return *ITFS;
   }
 
-  for (auto &List: IncludeTreeFileList) {
-    auto ID = CAS.parseID(List);
+  if (!IncludeTreeFileList.empty()) {
+    auto ID = CAS.parseID(IncludeTreeFileList);
     if (!ID)
       return ID.takeError();
 
     auto Ref = CAS.getReference(*ID);
     if (!Ref)
       return createCASObjectNotFoundError(*ID);
-    auto IT = clang::cas::IncludeTree::FileList::get(CAS, *Ref);
-    if (!IT)
-      return IT.takeError();
+    auto ITF = clang::cas::IncludeTree::FileList::get(CAS, *Ref);
+    if (!ITF)
+      return ITF.takeError();
 
-    auto Err = IT->forEachFile(
-        [&](clang::cas::IncludeTree::File File,
-            clang::cas::IncludeTree::FileList::FileSizeTy Size) -> llvm::Error {
-          Files.push_back({File.getRef(), Size});
-          return llvm::Error::success();
-        });
+    auto ITFS = clang::cas::createIncludeTreeFileSystem(*ITF);
+    if (!ITFS)
+      return ITFS.takeError();
 
-    if (Err)
-      return std::move(Err);
+    return *ITFS;
   }
 
-  auto ITFS = clang::cas::createIncludeTreeFileSystem(CAS, Files);
-  if (!ITFS)
-    return ITFS.takeError();
-
-  CASFS->pushOverlay(std::move(*ITFS));
-
-  return CASFS;
+  return nullptr;
 }
 
 std::vector<std::string> remapPathsFromCommandLine(
diff --git a/lib/Frontend/CompileJobCacheKey.cpp b/lib/Frontend/CompileJobCacheKey.cpp
index bc9005e3d2f2e..7a844cf4a88f2 100644
--- a/lib/Frontend/CompileJobCacheKey.cpp
+++ b/lib/Frontend/CompileJobCacheKey.cpp
@@ -72,14 +72,14 @@ llvm::Expected<llvm::cas::ObjectRef> swift::createCompileJobBaseCacheKey(
   }
 
   llvm::cas::HierarchicalTreeBuilder Builder;
-  auto CMD = CAS.storeFromString(std::nullopt, CommandLine);
+  auto CMD = CAS.storeFromString(/*Refs*/ {}, CommandLine);
   if (!CMD)
     return CMD.takeError();
   Builder.push(*CMD, llvm::cas::TreeEntry::Regular, "command-line");
 
   // FIXME: The version is maybe insufficient...
   auto Version =
-      CAS.storeFromString(std::nullopt, version::getSwiftFullVersion());
+      CAS.storeFromString(/*Refs*/ {}, version::getSwiftFullVersion());
   if (!Version)
     return Version.takeError();
   Builder.push(*Version, llvm::cas::TreeEntry::Regular, "version");
@@ -105,17 +105,23 @@ swift::createCompileJobCacheKeyForOutput(llvm::cas::ObjectStore &CAS,
   return CAS.storeFromString({BaseKey}, OS.str());
 }
 
+static llvm::Error validateCacheKeyNode(llvm::cas::ObjectProxy Proxy) {
+  if (Proxy.getData().size() != sizeof(uint32_t))
+    return llvm::createStringError("incorrect size for cache key node");
+  if (Proxy.getNumReferences() != 1)
+    return llvm::createStringError("incorrect child number for cache key node");
+
+  return llvm::Error::success();
+}
+
 llvm::Error swift::printCompileJobCacheKey(llvm::cas::ObjectStore &CAS,
                                            llvm::cas::ObjectRef Key,
                                            llvm::raw_ostream &OS) {
   auto Proxy = CAS.getProxy(Key);
   if (!Proxy)
     return Proxy.takeError();
-
-  if (Proxy->getData().size() != sizeof(uint32_t))
-    return llvm::createStringError("incorrect size for cache key node");
-  if (Proxy->getNumReferences() != 1)
-    return llvm::createStringError("incorrect child number for cache key node");
+  if (auto Err = validateCacheKeyNode(*Proxy))
+    return Err;
 
   uint32_t InputIndex = llvm::support::endian::read<uint32_t>(
       Proxy->getData().data(), llvm::endianness::little);
@@ -153,3 +159,41 @@ llvm::Error swift::printCompileJobCacheKey(llvm::cas::ObjectStore &CAS,
 
   return llvm::Error::success();
 }
+
+llvm::Error
+swift::iterateCommandLine(llvm::cas::ObjectStore &CAS, llvm::cas::ObjectRef Key,
+                          std::function<llvm::Error(StringRef)> Callback) {
+  auto Proxy = CAS.getProxy(Key);
+  if (!Proxy)
+    return Proxy.takeError();
+
+  if (auto Err = validateCacheKeyNode(*Proxy))
+    return Err;
+
+  auto Base = Proxy->getReference(0);
+  llvm::cas::TreeSchema Schema(CAS);
+  auto Tree = Schema.load(Base);
+  if (!Tree)
+    return Tree.takeError();
+
+  std::string BaseStr;
+  llvm::raw_string_ostream BaseOS(BaseStr);
+  return Tree->forEachEntry(
+      [&](const llvm::cas::NamedTreeEntry &Entry) -> llvm::Error {
+        auto Ref = Entry.getRef();
+        auto DataProxy = CAS.getProxy(Ref);
+        if (!DataProxy)
+          return DataProxy.takeError();
+
+        if (Entry.getName() != "command-line")
+          return llvm::Error::success();
+
+        StringRef Line, Remain = DataProxy->getData();
+        while (!Remain.empty()) {
+          std::tie(Line, Remain) = Remain.split(0);
+          if (auto Err = Callback(Line))
+            return Err;
+        }
+        return llvm::Error::success();
+      });
+}
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 217011b0f0e24..a7a9e52e00fff 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -35,6 +35,7 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/LineIterator.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/PrefixMapper.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/WithColor.h"
@@ -55,17 +56,6 @@ swift::CompilerInvocation::CompilerInvocation() {
   setTargetTriple(llvm::sys::getDefaultTargetTriple());
 }
 
-/// Converts a llvm::Triple to a llvm::VersionTuple.
-static llvm::VersionTuple
-getVersionTuple(const llvm::Triple &triple) {
-  if (triple.isMacOSX()) {
-    llvm::VersionTuple OSVersion;
-    triple.getMacOSXVersion(OSVersion);
-    return OSVersion;
-  }
-  return triple.getOSVersion();
-}
-
 void CompilerInvocation::computeRuntimeResourcePathFromExecutablePath(
     StringRef mainExecutablePath, bool shared,
     llvm::SmallVectorImpl<char> &runtimeResourcePath) {
@@ -254,7 +244,7 @@ static void updateRuntimeLibraryPaths(SearchPathOptions &SearchPathOpts,
     SearchPathOpts.RuntimeLibraryPaths.push_back(DARWIN_OS_LIBRARY_PATH);
 
   // If this is set, we don't want any runtime import paths.
-  if (SearchPathOpts.SkipRuntimeLibraryImportPaths) {
+  if (SearchPathOpts.SkipAllImplicitImportPaths) {
     SearchPathOpts.setRuntimeLibraryImportPaths({});
     return;
   }
@@ -270,7 +260,7 @@ static void updateRuntimeLibraryPaths(SearchPathOptions &SearchPathOpts,
     RuntimeLibraryImportPaths.push_back(std::string(LibPath.str()));
   }
 
-  if (!SearchPathOpts.ExcludeSDKPathsFromRuntimeLibraryImportPaths && !SearchPathOpts.getSDKPath().empty()) {
+  if (!SearchPathOpts.SkipSDKImportPaths && !SearchPathOpts.getSDKPath().empty()) {
     const char *swiftDir = FrontendOpts.UseSharedResourceFolder
       ? "swift" : "swift_static";
 
@@ -300,6 +290,37 @@ static void updateRuntimeLibraryPaths(SearchPathOptions &SearchPathOpts,
   SearchPathOpts.setRuntimeLibraryImportPaths(RuntimeLibraryImportPaths);
 }
 
+static void
+updateImplicitFrameworkSearchPaths(SearchPathOptions &SearchPathOpts,
+                                   const LangOptions &LangOpts) {
+  if (SearchPathOpts.SkipAllImplicitImportPaths) {
+    SearchPathOpts.setImplicitFrameworkSearchPaths({});
+    return;
+  }
+
+  std::vector<std::string> ImplicitFrameworkSearchPaths;
+  if (LangOpts.Target.isOSDarwin()) {
+    if (!SearchPathOpts.SkipSDKImportPaths &&
+        !SearchPathOpts.getSDKPath().empty()) {
+      SmallString<128> SDKPath(SearchPathOpts.getSDKPath());
+
+      SmallString<128> systemFrameworksScratch(SDKPath);
+      llvm::sys::path::append(systemFrameworksScratch, "System", "Library",
+                              "Frameworks");
+      SmallString<128> systemSubFrameworksScratch(SDKPath);
+      llvm::sys::path::append(systemSubFrameworksScratch, "System", "Library",
+                              "SubFrameworks");
+      SmallString<128> frameworksScratch(SDKPath);
+      llvm::sys::path::append(frameworksScratch, "Library", "Frameworks");
+
+      ImplicitFrameworkSearchPaths = {systemFrameworksScratch.str().str(),
+                                      systemSubFrameworksScratch.str().str(),
+                                      frameworksScratch.str().str()};
+    }
+  }
+  SearchPathOpts.setImplicitFrameworkSearchPaths(ImplicitFrameworkSearchPaths);
+}
+
 static void
 setIRGenOutputOptsFromFrontendOptions(IRGenOptions &IRGenOpts,
                                       const FrontendOptions &FrontendOpts) {
@@ -342,6 +363,8 @@ setBridgingHeaderFromFrontendOptions(ClangImporterOptions &ImporterOpts,
   if (!FrontendOpts.InputsAndOutputs.hasInputs())
     return;
 
+  ImporterOpts.BridgingHeaderIsInternal = FrontendOpts.ImportHeaderAsInternal;
+
   // If we aren't asked to output a bridging header, we don't need to set this.
   if (ImporterOpts.PrecompiledHeaderOutputDir.empty())
     return;
@@ -350,6 +373,13 @@ setBridgingHeaderFromFrontendOptions(ClangImporterOptions &ImporterOpts,
       FrontendOpts.InputsAndOutputs.getFilenameOfFirstInput();
 }
 
+void CompilerInvocation::computeAArch64TBIOptions() {
+  auto &LLVMArgs = getFrontendOptions().LLVMArgs;
+  auto aarch64_use_tbi =
+      std::find(LLVMArgs.begin(), LLVMArgs.end(), "-aarch64-use-tbi");
+  IRGenOpts.HasAArch64TBI = aarch64_use_tbi != LLVMArgs.end();
+}
+
 void CompilerInvocation::computeCXXStdlibOptions() {
   // The MSVC driver in Clang is not aware of the C++ stdlib, and currently
   // always assumes libstdc++, which is incorrect: the Microsoft stdlib is
@@ -360,7 +390,8 @@ void CompilerInvocation::computeCXXStdlibOptions() {
     // (see https://reviews.llvm.org/D101479).
     LangOpts.CXXStdlib = CXXStdlibKind::Msvcprt;
     LangOpts.PlatformDefaultCXXStdlib = CXXStdlibKind::Msvcprt;
-  } else if (LangOpts.Target.isOSLinux() || LangOpts.Target.isOSDarwin()) {
+  } else if (LangOpts.Target.isOSLinux() || LangOpts.Target.isOSDarwin() ||
+             LangOpts.Target.isOSFreeBSD()) {
     auto [clangDriver, clangDiagEngine] =
         ClangImporter::createClangDriver(LangOpts, ClangImporterOpts);
     auto clangDriverArgs = ClangImporter::createClangArgs(
@@ -411,11 +442,13 @@ void CompilerInvocation::setTargetTriple(StringRef Triple) {
 void CompilerInvocation::setTargetTriple(const llvm::Triple &Triple) {
   LangOpts.setTarget(Triple);
   updateRuntimeLibraryPaths(SearchPathOpts, FrontendOpts, LangOpts);
+  updateImplicitFrameworkSearchPaths(SearchPathOpts, LangOpts);
 }
 
 void CompilerInvocation::setSDKPath(const std::string &Path) {
   SearchPathOpts.setSDKPath(Path);
   updateRuntimeLibraryPaths(SearchPathOpts, FrontendOpts, LangOpts);
+  updateImplicitFrameworkSearchPaths(SearchPathOpts, LangOpts);
 }
 
 bool CompilerInvocation::setModuleAliasMap(std::vector<std::string> args,
@@ -537,8 +570,8 @@ static bool ShouldIncludeModuleInterfaceArg(const Arg *A) {
   if (!A->getOption().matches(options::OPT_enable_experimental_feature))
     return true;
 
-  if (auto feature = getExperimentalFeature(A->getValue())) {
-    return swift::includeInModuleInterface(*feature);
+  if (auto feature = Feature::getExperimentalFeature(A->getValue())) {
+    return feature->includeInModuleInterface();
   }
 
   return true;
@@ -649,7 +682,8 @@ static void diagnoseCxxInteropCompatMode(Arg *verArg, ArgList &Args,
 }
 
 void LangOptions::setCxxInteropFromArgs(ArgList &Args,
-                                        swift::DiagnosticEngine &Diags) {
+                                        swift::DiagnosticEngine &Diags,
+                                        const FrontendOptions &FrontendOpts) {
   if (Arg *A = Args.getLastArg(options::OPT_cxx_interoperability_mode)) {
     if (Args.hasArg(options::OPT_enable_experimental_cxx_interop)) {
       Diags.diagnose(SourceLoc(), diag::dont_enable_interop_and_compat);
@@ -704,7 +738,12 @@ void LangOptions::setCxxInteropFromArgs(ArgList &Args,
     // version, and is either 4, 5, 6, or 7 (even though only 5.9 and 6.* make
     // any sense). For now, we don't actually care about the version, so we'll
     // just use version 6 (i.e., 'swift-6') to mean that C++ interop mode is on.
-    if (EnableCXXInterop)
+    //
+    // FIXME: We always declare the 'Darwin' module as formally having been built
+    // without C++Interop, for compatibility with prior versions. Once we are certain
+    // that we are only building against modules built with support of
+    // '-formal-cxx-interoperability-mode', this hard-coded check should be removed.
+    if (EnableCXXInterop && (FrontendOpts.ModuleName.compare("Darwin") != 0))
       FormalCxxInteropMode = {6};
     else
       FormalCxxInteropMode = std::nullopt;
@@ -748,8 +787,6 @@ static bool ParseCASArgs(CASOptions &Opts, ArgList &Args,
   Opts.CacheSkipReplay |= Args.hasArg(OPT_cache_disable_replay);
   if (const Arg *A = Args.getLastArg(OPT_cas_path))
     Opts.CASOpts.CASPath = A->getValue();
-  else if (Opts.CASOpts.CASPath.empty())
-    Opts.CASOpts.CASPath = llvm::cas::getDefaultOnDiskCASPath();
 
   if (const Arg *A = Args.getLastArg(OPT_cas_plugin_path))
     Opts.CASOpts.PluginPath = A->getValue();
@@ -761,12 +798,12 @@ static bool ParseCASArgs(CASOptions &Opts, ArgList &Args,
                                             std::string(Value));
   }
 
-  for (const auto &A : Args.getAllArgValues(OPT_cas_fs))
-    Opts.CASFSRootIDs.emplace_back(A);
-  for (const auto &A : Args.getAllArgValues(OPT_clang_include_tree_root))
-    Opts.ClangIncludeTrees.emplace_back(A);
-  for (const auto &A : Args.getAllArgValues(OPT_clang_include_tree_filelist))
-    Opts.ClangIncludeTreeFileList.emplace_back(A);
+  Opts.ImportModuleFromCAS |= Args.hasArg(OPT_module_import_from_cas);
+
+  if (auto *A = Args.getLastArg(OPT_clang_include_tree_root))
+    Opts.ClangIncludeTree = A->getValue();
+  if (auto *A = Args.getLastArg(OPT_clang_include_tree_filelist))
+    Opts.ClangIncludeTreeFileList = A->getValue();
 
   if (const Arg *A = Args.getLastArg(OPT_input_file_key))
     Opts.InputFileKey = A->getValue();
@@ -774,8 +811,7 @@ static bool ParseCASArgs(CASOptions &Opts, ArgList &Args,
   if (const Arg*A = Args.getLastArg(OPT_bridging_header_pch_key))
     Opts.BridgingHeaderPCHCacheKey = A->getValue();
 
-  if (!Opts.CASFSRootIDs.empty() || !Opts.ClangIncludeTrees.empty() ||
-      !Opts.ClangIncludeTreeFileList.empty())
+  if (!Opts.ClangIncludeTree.empty() || !Opts.ClangIncludeTreeFileList.empty())
     Opts.HasImmutableFileSystem = true;
 
   return false;
@@ -810,13 +846,14 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
     // Collect some special case pseudo-features which should be processed
     // separately.
     if (argValue.starts_with("StrictConcurrency") ||
-        argValue.starts_with("AvailabilityMacro=")) {
+        argValue.starts_with("AvailabilityMacro=") ||
+        argValue.starts_with("RequiresObjC=")) {
       if (isEnableFeatureFlag)
         psuedoFeatures.push_back(argValue);
       continue;
     }
 
-    // For all other features, the argument format is `<name>[:adoption]`.
+    // For all other features, the argument format is `<name>[:migrate]`.
     StringRef featureName;
     std::optional<StringRef> featureMode;
     std::tie(featureName, featureMode) = argValue.rsplit(':');
@@ -824,7 +861,7 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
       featureMode = std::nullopt;
     }
 
-    auto feature = getUpcomingFeature(featureName);
+    auto feature = Feature::getUpcomingFeature(featureName);
     if (feature) {
       // Diagnose upcoming features enabled with -enable-experimental-feature.
       if (!isUpcomingFeatureFlag)
@@ -840,7 +877,7 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
       }
 
       // If the feature is also not a recognized experimental feature, skip it.
-      feature = getExperimentalFeature(featureName);
+      feature = Feature::getExperimentalFeature(featureName);
       if (!feature) {
         Diags.diagnose(SourceLoc(), diag::unrecognized_feature, featureName,
                        /*upcoming=*/false);
@@ -850,11 +887,11 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
 
     // If the current language mode enables the feature by default then
     // diagnose and skip it.
-    if (auto firstVersion = getFeatureLanguageVersion(*feature)) {
+    if (auto firstVersion = feature->getLanguageVersion()) {
       if (Opts.isSwiftVersionAtLeast(*firstVersion)) {
         Diags.diagnose(SourceLoc(),
                        diag::warning_upcoming_feature_on_by_default,
-                       getFeatureName(*feature), *firstVersion);
+                       feature->getName(), *firstVersion);
         continue;
       }
     }
@@ -862,7 +899,7 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
     // If this is a known experimental feature, allow it in +Asserts
     // (non-release) builds for testing purposes.
     if (Opts.RestrictNonProductionExperimentalFeatures &&
-        !isFeatureAvailableInProduction(*feature)) {
+        !feature->isAvailableInProduction()) {
       Diags.diagnose(SourceLoc(),
                      diag::experimental_not_supported_in_production,
                      featureName);
@@ -872,21 +909,21 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
 
     if (featureMode) {
       if (isEnableFeatureFlag) {
-        const auto isAdoptable = isFeatureAdoptable(*feature);
+        const auto isMigratable = feature->isMigratable();
 
         // Diagnose an invalid mode.
-        StringRef validModeName = "adoption";
+        StringRef validModeName = "migrate";
         if (*featureMode != validModeName) {
           Diags.diagnose(SourceLoc(), diag::invalid_feature_mode, *featureMode,
                          featureName,
                          /*didYouMean=*/validModeName,
-                         /*showDidYouMean=*/isAdoptable);
+                         /*showDidYouMean=*/isMigratable);
           continue;
         }
 
-        if (!isAdoptable) {
+        if (!isMigratable) {
           Diags.diagnose(SourceLoc(),
-                         diag::feature_does_not_support_adoption_mode,
+                         diag::feature_does_not_support_migration_mode,
                          featureName);
           continue;
         }
@@ -904,7 +941,7 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
 
     // Enable the feature if requested.
     if (isEnableFeatureFlag)
-      Opts.enableFeature(*feature, /*forAdoption=*/featureMode.has_value());
+      Opts.enableFeature(*feature, /*forMigration=*/featureMode.has_value());
   }
 
   // Since pseudo-features don't have a boolean on/off state, process them in
@@ -937,6 +974,11 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
       Opts.AvailabilityMacros.push_back(availability.str());
       continue;
     }
+
+    if (featureName->starts_with("RequiresObjC")) {
+      auto modules = featureName->split("=").second;
+      modules.split(Opts.ModulesRequiringObjC, ",");
+    }
   }
 
   // Map historical flags over to experimental features. We do this for all
@@ -964,10 +1006,13 @@ static bool ParseEnabledFeatureArgs(LangOptions &Opts, ArgList &Args,
   if (Args.hasArg(OPT_enable_builtin_module))
     Opts.enableFeature(Feature::BuiltinModule);
 
-  Opts.enableFeature(Feature::LayoutPrespecialization);
-
   if (Args.hasArg(OPT_strict_memory_safety))
     Opts.enableFeature(Feature::StrictMemorySafety);
+  else if (Args.hasArg(OPT_strict_memory_safety_migrate))
+    Opts.enableFeature(Feature::StrictMemorySafety, /*forMigration=*/true);
+
+  if (Args.hasArg(OPT_enable_library_evolution, OPT_enable_resilience))
+    Opts.enableFeature(Feature::LibraryEvolution);
 
   return HadError;
 }
@@ -994,6 +1039,20 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
     }
     if (!isValid)
       diagnoseSwiftVersion(vers, A, Args, Diags);
+  } else if (FrontendOpts.InputsAndOutputs.hasModuleInterfaceOutputPath()) {
+    Diags.diagnose({}, diag::error_module_interface_requires_language_mode)
+        .limitBehavior(DiagnosticBehavior::Warning);
+    // FIXME: Make this an error again (rdar://145168219)
+    // HadError = true;
+  }
+
+  if (auto A = Args.getLastArg(OPT_min_swift_runtime_version)) {
+    if (auto vers = VersionParser::parseVersionString(A->getValue(),
+                                                      SourceLoc(), &Diags)) {
+      Opts.MinSwiftRuntimeVersion = *vers;
+    } else {
+      return true;
+    }
   }
 
   if (auto A = Args.getLastArg(OPT_package_description_version)) {
@@ -1097,21 +1156,28 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
 
   Opts.WarnOnEditorPlaceholder |= Args.hasArg(OPT_warn_on_editor_placeholder);
 
-  if (auto A = Args.getLastArg(OPT_disable_typo_correction,
-                               OPT_typo_correction_limit)) {
-    if (A->getOption().matches(OPT_disable_typo_correction))
-      Opts.TypoCorrectionLimit = 0;
-    else {
-      unsigned limit;
-      if (StringRef(A->getValue()).getAsInteger(10, limit)) {
-        Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                       A->getAsString(Args), A->getValue());
-        HadError = true;
-      } else {
-        Opts.TypoCorrectionLimit = limit;
-      }
-    }
-  }
+  auto setUnsignedIntegerArgument =
+      [&Args, &Diags, &HadError](options::ID optionID, unsigned &valueToSet) {
+        if (const Arg *A = Args.getLastArg(optionID)) {
+          unsigned attempt;
+          if (StringRef(A->getValue()).getAsInteger(/*radix*/ 10, attempt)) {
+            Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
+                           A->getAsString(Args), A->getValue());
+            HadError = true;
+          } else {
+            valueToSet = attempt;
+          }
+        }
+      };
+
+  setUnsignedIntegerArgument(OPT_typo_correction_limit,
+                             Opts.TypoCorrectionLimit);
+
+  if (Args.hasArg(OPT_disable_typo_correction))
+    Opts.TypoCorrectionLimit = 0;
+
+  setUnsignedIntegerArgument(OPT_value_recursion_threshold,
+                             Opts.MaxCircularityDepth);
 
   if (auto A = Args.getLastArg(OPT_enable_target_os_checking,
                                OPT_disable_target_os_checking)) {
@@ -1187,17 +1253,6 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
     Opts.AvailabilityMacros.push_back(A->getValue());
   }
 
-  if (const Arg *A = Args.getLastArg(OPT_value_recursion_threshold)) {
-    unsigned threshold;
-    if (StringRef(A->getValue()).getAsInteger(10, threshold)) {
-      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                     A->getAsString(Args), A->getValue());
-      HadError = true;
-    } else {
-      Opts.MaxCircularityDepth = threshold;
-    }
-  }
-
   for (const Arg *A : Args.filtered(OPT_D)) {
     Opts.addCustomConditionalCompilationFlag(A->getValue());
   }
@@ -1205,7 +1260,7 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   // Add a future feature if it is not already implied by the language version.
   auto addFutureFeatureIfNotImplied = [&](Feature feature) {
     // Check if this feature was introduced already in this language version.
-    if (auto firstVersion = getFeatureLanguageVersion(feature)) {
+    if (auto firstVersion = feature.getLanguageVersion()) {
       if (Opts.isSwiftVersionAtLeast(*firstVersion))
         return;
     }
@@ -1364,12 +1419,6 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
     Opts.enableFeature(Feature::RegionBasedIsolation);
   }
 
-  // Get the executor factory name
-  if (const Arg *A = Args.getLastArg(OPT_executor_factory)) {
-    printf("Got executor-factory option\n");
-    Opts.ExecutorFactory = A->getValue();
-  }
-
   Opts.WarnImplicitOverrides =
     Args.hasArg(OPT_warn_implicit_overrides);
 
@@ -1393,6 +1442,9 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
     Opts.OptimizationRemarkMissedPattern =
         generateOptimizationRemarkRegex(Diags, Args, A);
 
+  if (const Arg *A = Args.getLastArg(OPT_access_notes_path))
+    Opts.AccessNotesPath = A->getValue();
+
   if (Arg *A = Args.getLastArg(OPT_Raccess_note)) {
     auto value =
         llvm::StringSwitch<std::optional<AccessNoteDiagnosticBehavior>>(
@@ -1428,8 +1480,6 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
 
   Opts.EnableSkipExplicitInterfaceModuleBuildRemarks = Args.hasArg(OPT_remark_skip_explicit_interface_build);
 
-  Opts.EnableABIInferenceRemarks = Args.hasArg(OPT_remark_abi_inference);
-
   if (Args.hasArg(OPT_experimental_skip_non_exportable_decls)) {
     // Only allow -experimental-skip-non-exportable-decls if either library
     // evolution is enabled (in which case the module's ABI is independent of
@@ -1454,7 +1504,7 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   if (Opts.AllowNonResilientAccess) {
     // Override the option to skip non-exportable decls.
     if (Opts.SkipNonExportableDecls) {
-      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overriden_by,
+      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overridden_by,
                      "-experimental-skip-non-exportable-decls",
                      "-allow-non-resilient-access");
       Opts.SkipNonExportableDecls = false;
@@ -1463,10 +1513,11 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
     if (Opts.AllowNonResilientAccess &&
         FrontendOptions::doesActionBuildModuleFromInterface(
             FrontendOpts.RequestedAction)) {
-      Diags.diagnose(
-          SourceLoc(), diag::warn_ignore_option_overriden_by,
-          "-allow-non-resilient-access",
-          "-compile-module-from-interface or -typecheck-module-from-interface");
+      if (FrontendOpts.RequestedAction !=
+          FrontendOptions::ActionType::TypecheckModuleFromInterface)
+        Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overridden_by,
+                       "-allow-non-resilient-access",
+                       "-compile-module-from-interface");
       Opts.AllowNonResilientAccess = false;
     }
   }
@@ -1535,17 +1586,19 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   if (const Arg *A = Args.getLastArg(OPT_clang_target_variant))
     Opts.ClangTargetVariant = llvm::Triple(A->getValue());
 
-  Opts.setCxxInteropFromArgs(Args, Diags);
+  Opts.setCxxInteropFromArgs(Args, Diags, FrontendOpts);
   if (!Args.hasArg(options::OPT_formal_cxx_interoperability_mode))
     ModuleInterfaceOpts.PublicFlags.IgnorableFlags +=
         " " + printFormalCxxInteropVersion(Opts);
 
+  Opts.UseStaticStandardLibrary = Args.hasArg(OPT_use_static_resource_dir);
   Opts.EnableObjCInterop =
       Args.hasFlag(OPT_enable_objc_interop, OPT_disable_objc_interop,
                    Target.isOSDarwin() && !Opts.hasFeature(Feature::Embedded));
 
-  Opts.CForeignReferenceTypes =
-      Args.hasArg(OPT_experimental_c_foreign_reference_types);
+  if (Args.hasArg(OPT_experimental_c_foreign_reference_types))
+    Diags.diagnose(SourceLoc(), diag::warn_flag_deprecated,
+                   "-experimental-c-foreign-reference-types");
 
   Opts.CxxInteropGettersSettersAsProperties = Args.hasArg(OPT_cxx_interop_getters_setters_as_properties);
   Opts.RequireCxxInteropToImportCxxInteropModule =
@@ -1586,7 +1639,7 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   // First, set up default minimum inlining target versions.
   auto getDefaultMinimumInliningTargetVersion =
       [&](const llvm::Triple &triple) -> llvm::VersionTuple {
-    const auto targetVersion = getVersionTuple(triple);
+    const auto targetVersion = getVersionForTriple(triple);
 
     // In API modules, default to the version when Swift first became available.
     if (Opts.LibraryLevel == LibraryLevel::API) {
@@ -1699,52 +1752,24 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   Opts.DumpMacroExpansions = Args.hasArg(
       OPT_dump_macro_expansions);
 
+  Opts.DumpSourceFileImports = Args.hasArg(
+      OPT_dump_source_file_imports);
+
   if (const Arg *A = Args.getLastArg(OPT_debug_requirement_machine))
     Opts.DebugRequirementMachine = A->getValue();
 
-  if (const Arg *A = Args.getLastArg(OPT_requirement_machine_max_rule_count)) {
-    unsigned limit;
-    if (StringRef(A->getValue()).getAsInteger(10, limit)) {
-      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                     A->getAsString(Args), A->getValue());
-      HadError = true;
-    } else {
-      Opts.RequirementMachineMaxRuleCount = limit;
-    }
-  }
-
-  if (const Arg *A = Args.getLastArg(OPT_requirement_machine_max_rule_length)) {
-    unsigned limit;
-    if (StringRef(A->getValue()).getAsInteger(10, limit)) {
-      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                     A->getAsString(Args), A->getValue());
-      HadError = true;
-    } else {
-      Opts.RequirementMachineMaxRuleLength = limit;
-    }
-  }
-
-  if (const Arg *A = Args.getLastArg(OPT_requirement_machine_max_concrete_nesting)) {
-    unsigned limit;
-    if (StringRef(A->getValue()).getAsInteger(10, limit)) {
-      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                     A->getAsString(Args), A->getValue());
-      HadError = true;
-    } else {
-      Opts.RequirementMachineMaxConcreteNesting = limit;
-    }
-  }
-
-  if (const Arg *A = Args.getLastArg(OPT_requirement_machine_max_split_concrete_equiv_class_attempts)) {
-    unsigned limit;
-    if (StringRef(A->getValue()).getAsInteger(10, limit)) {
-      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                     A->getAsString(Args), A->getValue());
-      HadError = true;
-    } else {
-      Opts.RequirementMachineMaxSplitConcreteEquivClassAttempts = limit;
-    }
-  }
+  setUnsignedIntegerArgument(OPT_requirement_machine_max_rule_count,
+                             Opts.RequirementMachineMaxRuleCount);
+  setUnsignedIntegerArgument(OPT_requirement_machine_max_rule_length,
+                             Opts.RequirementMachineMaxRuleLength);
+  setUnsignedIntegerArgument(OPT_requirement_machine_max_concrete_nesting,
+                             Opts.RequirementMachineMaxConcreteNesting);
+  setUnsignedIntegerArgument(OPT_requirement_machine_max_concrete_size,
+                             Opts.RequirementMachineMaxConcreteSize);
+  setUnsignedIntegerArgument(OPT_requirement_machine_max_type_differences,
+                             Opts.RequirementMachineMaxTypeDifferences);
+  setUnsignedIntegerArgument(OPT_requirement_machine_max_split_concrete_equiv_class_attempts,
+                             Opts.RequirementMachineMaxSplitConcreteEquivClassAttempts);
 
   if (Args.hasArg(OPT_disable_requirement_machine_concrete_contraction))
     Opts.EnableRequirementMachineConcreteContraction = false;
@@ -1758,6 +1783,11 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   if (Args.hasArg(OPT_enable_requirement_machine_opaque_archetypes))
     Opts.EnableRequirementMachineOpaqueArchetypes = true;
 
+  setUnsignedIntegerArgument(OPT_max_substitution_depth,
+                             Opts.MaxSubstitutionDepth);
+  setUnsignedIntegerArgument(OPT_max_substitution_count,
+                             Opts.MaxSubstitutionCount);
+
   if (Args.hasArg(OPT_enable_experimental_lifetime_dependence_inference))
     Opts.EnableExperimentalLifetimeDependenceInference = true;
   if (Args.hasArg(OPT_disable_experimental_lifetime_dependence_inference))
@@ -1786,12 +1816,13 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
       HadError = true;
     }
 
-    if (FrontendOpts.EnableLibraryEvolution) {
+    if (Opts.hasFeature(Feature::LibraryEvolution)) {
       Diags.diagnose(SourceLoc(), diag::evolution_with_embedded);
       HadError = true;
     }
 
-    if (!FrontendOpts.InputsAndOutputs.isWholeModule() && FrontendOptions::doesActionGenerateSIL(FrontendOpts.RequestedAction)) {
+    if (!FrontendOpts.InputsAndOutputs.isWholeModule() &&
+        FrontendOptions::doesActionGenerateSIL(FrontendOpts.RequestedAction)) {
       Diags.diagnose(SourceLoc(), diag::wmo_with_embedded);
       HadError = true;
     }
@@ -1840,8 +1871,10 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
     Opts.DefaultIsolationBehavior = DefaultIsolation::Nonisolated;
   }
 
-  if (Opts.DefaultIsolationBehavior == DefaultIsolation::MainActor)
+  if (Opts.DefaultIsolationBehavior == DefaultIsolation::MainActor) {
     Opts.enableFeature(Feature::InferIsolatedConformances);
+    Opts.enableFeature(Feature::NoExplicitNonIsolated);
+  }
 
 #if !defined(NDEBUG) && SWIFT_ENABLE_EXPERIMENTAL_PARSER_VALIDATION
   /// Enable round trip parsing via the new swift parser unless it is disabled
@@ -1883,11 +1916,13 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
                              Opts.WarnLongExpressionTypeChecking);
   setUnsignedIntegerArgument(OPT_solver_expression_time_threshold_EQ,
                              Opts.ExpressionTimeoutThreshold);
+  setUnsignedIntegerArgument(OPT_dynamic_member_lookup_depth_limit_EQ,
+                             Opts.DynamicMemberLookupDepthLimit);
   setUnsignedIntegerArgument(OPT_switch_checking_invocation_threshold_EQ,
                              Opts.SwitchCheckingInvocationThreshold);
   setUnsignedIntegerArgument(OPT_debug_constraints_attempt,
                              Opts.DebugConstraintSolverAttempt);
-  setUnsignedIntegerArgument(OPT_solver_memory_threshold,
+  setUnsignedIntegerArgument(OPT_solver_memory_threshold_EQ,
                              Opts.SolverMemoryThreshold);
   setUnsignedIntegerArgument(OPT_solver_scope_threshold_EQ,
                              Opts.SolverScopeThreshold);
@@ -1903,7 +1938,7 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
   if (Args.hasArg(
         OPT_experimental_skip_non_inlinable_function_bodies_without_types)) {
     if (LangOpts.AllowNonResilientAccess)
-      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overriden_by,
+      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overridden_by,
                      "-experimental-skip-non-inlinable-function-bodies-without-types",
                      "-allow-non-resilient-access");
     else
@@ -1914,7 +1949,7 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
   // body skipping.
   if (Args.hasArg(OPT_experimental_skip_non_inlinable_function_bodies)) {
     if (LangOpts.AllowNonResilientAccess)
-      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overriden_by,
+      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overridden_by,
                      "-experimental-skip-non-inlinable-function-bodies",
                      "-allow-non-resilient-access");
     else
@@ -1923,7 +1958,7 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
 
   if (Args.hasArg(OPT_tbd_is_installapi)) {
     if (LangOpts.AllowNonResilientAccess)
-      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overriden_by,
+      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overridden_by,
                      "-tbd-is-installapi",
                      "-allow-non-resilient-access");
     else
@@ -1932,7 +1967,7 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
 
   if (Args.hasArg(OPT_experimental_skip_all_function_bodies)) {
     if (LangOpts.AllowNonResilientAccess)
-      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overriden_by,
+      Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overridden_by,
                      "-experimental-skip-all-function-bodies",
                      "-allow-non-resilient-access");
     else
@@ -1951,8 +1986,8 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
         SWIFT_ONONE_SUPPORT);
   }
 
-  Opts.DisableConstraintSolverPerformanceHacks |=
-      Args.hasArg(OPT_disable_constraint_solver_performance_hacks);
+  Opts.EnableConstraintSolverPerformanceHacks |=
+      Args.hasArg(OPT_enable_constraint_solver_performance_hacks);
 
   Opts.EnableOperatorDesignatedTypes |=
       Args.hasArg(OPT_enable_operator_designated_types);
@@ -1981,12 +2016,13 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
     Opts.DebugForbidTypecheckPrefixes.push_back(A);
   }
 
-  if (Args.getLastArg(OPT_solver_disable_shrink))
-    Opts.SolverDisableShrink = true;
-
   if (Args.getLastArg(OPT_solver_disable_splitter))
     Opts.SolverDisableSplitter = true;
 
+  if (Args.hasArg(OPT_solver_enable_prepared_overloads) ||
+      Args.hasArg(OPT_solver_disable_prepared_overloads))
+    Opts.SolverEnablePreparedOverloads = Args.hasArg(OPT_solver_enable_prepared_overloads);
+
   if (FrontendOpts.RequestedAction == FrontendOptions::ActionType::Immediate)
     Opts.DeferToRuntime = true;
 
@@ -2009,7 +2045,7 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
 
   if (LangOpts.AllowNonResilientAccess &&
       Opts.EnableLazyTypecheck) {
-    Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overriden_by,
+    Diags.diagnose(SourceLoc(), diag::warn_ignore_option_overridden_by,
                    "-experimental-lazy-typecheck",
                    "-allow-non-resilient-access");
     Opts.EnableLazyTypecheck = false;
@@ -2096,10 +2132,32 @@ static bool ParseClangImporterArgs(ClangImporterOptions &Opts, ArgList &Args,
   else if (Args.hasArg(OPT_emit_pcm) || Args.hasArg(OPT_dump_pcm))
     Opts.Mode = ClangImporterOptions::Modes::PrecompiledModule;
 
-  if (auto *A = Args.getLastArg(OPT_import_objc_header))
+  bool hadNormalBridgingHeader = false;
+  if (auto *A = Args.getLastArg(OPT_import_bridging_header,
+                                OPT_internal_import_bridging_header)) {
     Opts.BridgingHeader = A->getValue();
-  if (auto *A = Args.getLastArg(OPT_import_pch))
+    Opts.BridgingHeaderIsInternal =
+        A->getOption().getID() == OPT_internal_import_bridging_header;
+  }
+  if (auto *A = Args.getLastArg(OPT_import_pch, OPT_internal_import_pch)) {
     Opts.BridgingHeaderPCH = A->getValue();
+    bool importAsInternal = A->getOption().getID() == OPT_internal_import_pch;
+    if (hadNormalBridgingHeader &&
+        importAsInternal != Opts.BridgingHeaderIsInternal) {
+      Diags.diagnose(SourceLoc(),
+                     diag::bridging_header_and_pch_internal_mismatch);
+    }
+    Opts.BridgingHeaderIsInternal = importAsInternal;
+  }
+
+  // Until we have some checking in place, internal bridging headers are a
+  // bit unsafe without library evolution.
+  if (Opts.BridgingHeaderIsInternal &&
+      !LangOpts.hasFeature(Feature::LibraryEvolution)) {
+    Diags.diagnose(SourceLoc(),
+                   diag::internal_bridging_header_without_library_evolution);
+  }
+
   Opts.DisableSwiftBridgeAttr |= Args.hasArg(OPT_disable_swift_bridge_attr);
 
   Opts.DisableOverlayModules |= Args.hasArg(OPT_emit_imported_modules);
@@ -2115,6 +2173,8 @@ static bool ParseClangImporterArgs(ClangImporterOptions &Opts, ArgList &Args,
     Opts.PCHDisableValidation |= Args.hasArg(OPT_pch_disable_validation);
   }
 
+  Opts.LoadVersionIndependentAPINotes |= Args.hasArg(OPT_version_independent_apinotes);
+
   if (FrontendOpts.DisableImplicitModules)
     Opts.DisableImplicitClangModules = true;
 
@@ -2133,15 +2193,14 @@ static bool ParseClangImporterArgs(ClangImporterOptions &Opts, ArgList &Args,
   Opts.DisableSourceImport |=
       Args.hasArg(OPT_disable_clangimporter_source_import);
 
+  if (Args.hasArg(OPT_disable_const_value_importing))
+      Opts.EnableConstValueImporting = false;
+
   Opts.ClangImporterDirectCC1Scan |=
       Args.hasArg(OPT_experimental_clang_importer_direct_cc1_scan);
   // Forward the FrontendOptions to clang importer option so it can be
   // accessed when creating clang module compilation invocation.
   if (CASOpts.EnableCaching) {
-    // Only set UseClangIncludeTree when caching is enabled since it is not
-    // useful in non-caching context.
-    Opts.UseClangIncludeTree |= !Args.hasArg(OPT_no_clang_include_tree);
-    Opts.HasClangIncludeTreeRoot |= Args.hasArg(OPT_clang_include_tree_root);
     // Caching requires direct clang import cc1 scanning.
     Opts.ClangImporterDirectCC1Scan = true;
   }
@@ -2221,16 +2280,28 @@ static void ParseSymbolGraphArgs(symbolgraphgen::SymbolGraphOptions &Opts,
     Opts.MinimumAccessLevel = AccessLevel::Public;
   }
 
+  if (auto *A = Args.getLastArg(OPT_symbol_graph_allow_availability_platforms,
+        OPT_symbol_graph_block_availability_platforms)) {
+    llvm::SmallVector<StringRef> AvailabilityPlatforms;
+    StringRef(A->getValue())
+        .split(AvailabilityPlatforms, ',', /*MaxSplits*/ -1,
+               /*KeepEmpty*/ false);
+    Opts.AvailabilityPlatforms = llvm::DenseSet<StringRef>(
+        AvailabilityPlatforms.begin(), AvailabilityPlatforms.end());
+    Opts.AvailabilityIsBlockList = A->getOption().matches(OPT_symbol_graph_block_availability_platforms);
+  }
+
   // default values for generating symbol graphs during a build
-  Opts.PrettyPrint = false;
-  Opts.EmitSynthesizedMembers = true;
+  Opts.PrettyPrint = Args.hasArg(OPT_symbol_graph_pretty_print);
+  Opts.EmitSynthesizedMembers = !Args.hasArg(OPT_symbol_graph_skip_synthesized_members);
+  Opts.SkipInheritedDocs = !Args.hasArg(OPT_symbol_graph_skip_inherited_docs);
   Opts.PrintMessages = false;
   Opts.IncludeClangDocs = false;
 }
 
 static bool validateSwiftModuleFileArgumentAndAdd(const std::string &swiftModuleArgument,
                                                   DiagnosticEngine &Diags,
-                                                  std::vector<std::pair<std::string, std::string>> &ExplicitSwiftModuleInputs) {
+                                                  llvm::StringMap<std::string> &ExplicitSwiftModuleInputs) {
   std::size_t foundDelimeterPos = swiftModuleArgument.find_first_of("=");
   if (foundDelimeterPos == std::string::npos) {
     Diags.diagnose(SourceLoc(), diag::error_swift_module_file_requires_delimeter,
@@ -2243,7 +2314,15 @@ static bool validateSwiftModuleFileArgumentAndAdd(const std::string &swiftModule
     Diags.diagnose(SourceLoc(), diag::error_bad_module_name, moduleName, false);
     return true;
   }
-  ExplicitSwiftModuleInputs.emplace_back(std::make_pair(moduleName, modulePath));
+
+  auto priorEntryIt = ExplicitSwiftModuleInputs.find(moduleName);
+  if (priorEntryIt != ExplicitSwiftModuleInputs.end()) {
+    Diags.diagnose(SourceLoc(), diag::warn_multiple_module_inputs_same_name,
+                   moduleName, priorEntryIt->getValue(), modulePath);
+    ExplicitSwiftModuleInputs[moduleName] = modulePath;
+  } else
+    ExplicitSwiftModuleInputs.insert(std::make_pair(moduleName, modulePath));
+
   return false;
 }
 
@@ -2384,8 +2463,8 @@ static bool ParseSearchPathArgs(SearchPathOptions &Opts, ArgList &Args,
   if (const Arg *A = Args.getLastArg(OPT_resource_dir))
     Opts.RuntimeResourcePath = A->getValue();
 
-  Opts.SkipRuntimeLibraryImportPaths |= Args.hasArg(OPT_nostdimport);
-  Opts.ExcludeSDKPathsFromRuntimeLibraryImportPaths |= Args.hasArg(OPT_nostdlibimport);
+  Opts.SkipAllImplicitImportPaths |= Args.hasArg(OPT_nostdimport);
+  Opts.SkipSDKImportPaths |= Args.hasArg(OPT_nostdlibimport);
 
   Opts.DisableModulesValidateSystemDependencies |=
       Args.hasArg(OPT_disable_modules_validate_system_headers);
@@ -2400,8 +2479,6 @@ static bool ParseSearchPathArgs(SearchPathOptions &Opts, ArgList &Args,
   for (auto A: Args.filtered(OPT_candidate_module_file)) {
     Opts.CandidateCompiledModules.push_back(resolveSearchPath(A->getValue()));
   }
-  if (const Arg *A = Args.getLastArg(OPT_placeholder_dependency_module_map))
-    Opts.PlaceholderDependencyModuleMap = A->getValue();
 
   if (const Arg *A = Args.getLastArg(OPT_const_gather_protocols_file))
     Opts.ConstGatherProtocolListFilePath = A->getValue();
@@ -2413,10 +2490,14 @@ static bool ParseSearchPathArgs(SearchPathOptions &Opts, ArgList &Args,
     auto SplitMap = StringRef(A).split('=');
     Opts.DeserializedPathRecoverer.addMapping(SplitMap.first, SplitMap.second);
   }
-  for (StringRef Opt : Args.getAllArgValues(OPT_scanner_prefix_map)) {
-    Opts.ScannerPrefixMapper.push_back(Opt.str());
+  
+  for (const Arg *A : Args.filtered(OPT_scanner_prefix_map_paths)) {
+    Opts.ScannerPrefixMapper.push_back({A->getValue(0), A->getValue(1)});
   }
 
+  Opts.ResolvedPluginVerification |=
+      Args.hasArg(OPT_resolved_plugin_verification);
+
   // rdar://132340493 disable scanner-side validation for non-caching builds
   Opts.ScannerModuleValidation |= Args.hasFlag(OPT_scanner_module_validation,
                                                OPT_no_scanner_module_validation,
@@ -2489,6 +2570,21 @@ static bool ParseSearchPathArgs(SearchPathOptions &Opts, ArgList &Args,
   return false;
 }
 
+/// Determine whether the given argument list enables Embedded Swift.
+static bool isEmbedded(ArgList &args) {
+  using namespace swift::options;
+
+  for (const Arg *arg : args.filtered_reverse(
+           OPT_enable_experimental_feature, OPT_disable_experimental_feature)) {
+    if (llvm::StringRef(arg->getValue()) != "Embedded")
+      continue;
+
+    return arg->getOption().matches(OPT_enable_experimental_feature);
+  }
+
+  return false;
+}
+
 static bool ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
                                 DiagnosticEngine &Diags) {
   // NOTE: This executes at the beginning of parsing the command line and cannot
@@ -2501,6 +2597,7 @@ static bool ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
   if (Args.hasArg(OPT_verify_apply_fixes))
     Opts.VerifyMode = DiagnosticOptions::VerifyAndApplyFixes;
   Opts.VerifyIgnoreUnknown |= Args.hasArg(OPT_verify_ignore_unknown);
+  Opts.VerifyIgnoreUnrelated |= Args.hasArg(OPT_verify_ignore_unrelated);
   Opts.SkipDiagnosticPasses |= Args.hasArg(OPT_disable_diagnostic_passes);
   Opts.ShowDiagnosticsAfterFatalError |=
     Args.hasArg(OPT_show_diagnostics_after_fatal);
@@ -2542,8 +2639,30 @@ static bool ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
       Opts.EmitMacroExpansionFiles = !negated;
   }
 
-  Opts.FixitCodeForAllDiagnostics |= Args.hasArg(OPT_fixit_all);
+  {
+    OptSpecifier obsoleteOpts[] = {
+      OPT_fixit_all,
+      OPT_emit_fixits_path,
+    };
+
+    for (auto option: obsoleteOpts) {
+      if (auto *arg = Args.getLastArg(option)) {
+        Diags.diagnose(SourceLoc(), diag::ignoring_option_obsolete,
+                       arg->getOption().getPrefixedName());
+      }
+    }
+  }
+
+  // If the "embedded" flag was provided, enable the EmbeddedRestrictions
+  // warning group. This group is opt-in in non-Embedded builds.
+  if (isEmbedded(Args) && !Args.hasArg(OPT_suppress_warnings)) {
+    Opts.WarningsAsErrorsRules.push_back(
+        WarningAsErrorRule(WarningAsErrorRule::Action::Disable,
+                           "EmbeddedRestrictions"));
+  }
+
   Opts.SuppressWarnings |= Args.hasArg(OPT_suppress_warnings);
+  Opts.SuppressNotes |= Args.hasArg(OPT_suppress_notes);
   Opts.SuppressRemarks |= Args.hasArg(OPT_suppress_remarks);
   for (const Arg *arg : Args.filtered(OPT_warning_treating_Group)) {
     Opts.WarningsAsErrorsRules.push_back([&] {
@@ -2624,6 +2743,9 @@ static void configureDiagnosticEngine(
   if (Options.SuppressWarnings) {
     Diagnostics.setSuppressWarnings(true);
   }
+  if (Options.SuppressNotes) {
+    Diagnostics.setSuppressNotes(true);
+  }
   if (Options.SuppressRemarks) {
     Diagnostics.setSuppressRemarks(true);
   }
@@ -2633,7 +2755,7 @@ static void configureDiagnosticEngine(
   std::string docsPath = Options.DiagnosticDocumentationPath;
   if (docsPath.empty()) {
     // Point at the latest Markdown documentation on GitHub.
-    docsPath = "https://github.com/swiftlang/swift/tree/main/userdocs/diagnostics";
+    docsPath = "https://docs.swift.org/compiler/documentation/diagnostics";
   }
   Diagnostics.setDiagnosticDocumentationPath(docsPath);
 
@@ -2829,34 +2951,34 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
   if (Arg *A = Args.getLastArg(OPT_copy_propagation_state_EQ)) {
     specifiedCopyPropagationOption =
         llvm::StringSwitch<std::optional<CopyPropagationOption>>(A->getValue())
-            .Case("true", CopyPropagationOption::On)
+            .Case("always", CopyPropagationOption::Always)
+            .Case("optimizing", CopyPropagationOption::Optimizing)
             .Case("false", CopyPropagationOption::Off)
             .Case("requested-passes-only",
                   CopyPropagationOption::RequestedPassesOnly)
             .Default(std::nullopt);
+
+    // Error if copy propagation has been set via the flag at the same time.
+    if (auto *Flag = Args.getLastArg(OPT_enable_copy_propagation)) {
+      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_combination,
+                       Flag->getAsString(Args),
+                       A->getAsString(Args));
+    }
   }
-  if (Args.hasArg(OPT_enable_copy_propagation)) {
-    if (specifiedCopyPropagationOption) {
-      if (*specifiedCopyPropagationOption == CopyPropagationOption::Off) {
-        // Error if copy propagation has been set to ::Off via the meta-var form
-        // and enabled via the flag.
-        Diags.diagnose(SourceLoc(), diag::error_invalid_arg_combination,
-                       "enable-copy-propagation",
-                       "enable-copy-propagation=false");
-        return true;
-      } else if (*specifiedCopyPropagationOption ==
-                 CopyPropagationOption::RequestedPassesOnly) {
-        // Error if copy propagation has been set to ::RequestedPassesOnly via
-        // the meta-var form and enabled via the flag.
-        Diags.diagnose(SourceLoc(), diag::error_invalid_arg_combination,
-                       "enable-copy-propagation",
-                       "enable-copy-propagation=requested-passes-only");
-        return true;
-      }
-    } else {
-      specifiedCopyPropagationOption = CopyPropagationOption::On;
+  // Have ManualOwnership imply MandatoryCopyPropagation.
+  // Once that pass becomes enabled by default, we don't need this.
+  if (LangOpts.hasFeature(ManualOwnership)) {
+    specifiedCopyPropagationOption = CopyPropagationOption::Always;
+
+    if (auto *Flag = Args.getLastArg(OPT_copy_propagation_state_EQ)) {
+      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_combination,
+                       Flag->getAsString(Args),
+                       "-enable-experimental-feature ManualOwnership");
     }
   }
+  if (Args.hasArg(OPT_enable_copy_propagation)) {
+    specifiedCopyPropagationOption = CopyPropagationOption::Always;
+  }
   if (specifiedCopyPropagationOption) {
     Opts.CopyPropagation = *specifiedCopyPropagationOption;
   }
@@ -2887,7 +3009,7 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
 
   // Unless overridden below, enabling copy propagation means enabling lexical
   // lifetimes.
-  if (Opts.CopyPropagation == CopyPropagationOption::On) {
+  if (Opts.CopyPropagation >= CopyPropagationOption::Optimizing) {
     Opts.LexicalLifetimes = LexicalLifetimesOption::On;
     Opts.DestroyHoisting = DestroyHoistingOption::On;
   }
@@ -2939,7 +3061,6 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
         enablePackMetadataStackPromotionFlag.value();
 
   Opts.EnableARCOptimizations &= !Args.hasArg(OPT_disable_arc_opts);
-  Opts.EnableOSSAModules |= Args.hasArg(OPT_enable_ossa_modules);
   Opts.EnableRecompilationToOSSAModule |=
       Args.hasArg(OPT_enable_recompilation_to_ossa_module);
   Opts.EnableOSSAOptimizations &= !Args.hasArg(OPT_disable_ossa_opts);
@@ -2969,10 +3090,11 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
       Args.hasArg(OPT_PackageCMO) ||
       LangOpts.hasFeature(Feature::PackageCMO)) {
     if (!LangOpts.AllowNonResilientAccess) {
-      Diags.diagnose(SourceLoc(), diag::ignoring_option_requires_option,
-                     "-package-cmo",
-                     "-allow-non-resilient-access");
-    } else if (!FEOpts.EnableLibraryEvolution) {
+      if (FEOpts.RequestedAction !=
+          FrontendOptions::ActionType::TypecheckModuleFromInterface)
+        Diags.diagnose(SourceLoc(), diag::ignoring_option_requires_option,
+                       "-package-cmo", "-allow-non-resilient-access");
+    } else if (!LangOpts.hasFeature(Feature::LibraryEvolution)) {
       Diags.diagnose(SourceLoc(), diag::package_cmo_requires_library_evolution);
     } else {
       Opts.EnableSerializePackage = true;
@@ -3032,6 +3154,10 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
     Opts.OptRecordFormat = *formatOrErr;
   }
 
+  Opts.EnableGlobalAssemblyVision = Args.hasFlag(
+      OPT_enable_assembly_vision_all, OPT_disable_assembly_vision_all,
+      Opts.EnableGlobalAssemblyVision);
+
   if (const Arg *A = Args.getLastArg(OPT_save_optimization_record_passes))
     Opts.OptRecordPasses = A->getValue();
 
@@ -3114,9 +3240,6 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
 
   Opts.NoAllocations = Args.hasArg(OPT_no_allocations);
 
-  Opts.EnableExperimentalSwiftBasedClosureSpecialization =
-      Args.hasArg(OPT_enable_experimental_swift_based_closure_specialization);
-
   // If these optimizations are enabled never preserve functions for the
   // debugger.
   Opts.ShouldFunctionsBePreservedToDebugger =
@@ -3130,6 +3253,16 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
   Opts.EnableAddressDependencies = Args.hasFlag(
       OPT_enable_address_dependencies, OPT_disable_address_dependencies,
       Opts.EnableAddressDependencies);
+
+  if (LangOpts.Target.isOSDarwin() || LangOpts.Target.isOSLinux()) {
+    // On Darwin and Linux, use yield_once_2 by default.
+    Opts.CoroutineAccessorsUseYieldOnce2 = true;
+  }
+  Opts.CoroutineAccessorsUseYieldOnce2 =
+      Args.hasFlag(OPT_enable_callee_allocated_coro_abi,
+                   OPT_disable_callee_allocated_coro_abi,
+                   Opts.CoroutineAccessorsUseYieldOnce2);
+
   Opts.MergeableTraps = Args.hasArg(OPT_mergeable_traps);
 
   return false;
@@ -3441,6 +3574,21 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
 
   Opts.DebugInfoForProfiling |= Args.hasArg(OPT_debug_info_for_profiling);
 
+
+  if (const Arg *A = Args.getLastArg(OPT_min_valid_pointer_value)) {
+    // The LeastValidPointerValue is hard-coded in the runtime. Therefore it
+    // can only safely customized in embedded swift - which doesn't have a runtime.
+    if (!LangOpts.hasFeature(Feature::Embedded)) {
+      Diags.diagnose(SourceLoc(), diag::min_ptr_value_without_embedded);
+      return true;
+    }
+    if (StringRef(A->getValue()).getAsInteger(0, Opts.CustomLeastValidPointerValue)) {
+      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
+                     A->getAsString(Args), A->getValue());
+      return true;
+    }
+  }
+
   Opts.PrintInlineTree |= Args.hasArg(OPT_print_llvm_inline_tree);
   // Always producing all outputs when caching is enabled.
   Opts.AlwaysCompile |= Args.hasArg(OPT_always_compile_output_files) ||
@@ -3623,6 +3771,8 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
         runtimeCompatibilityVersion = llvm::VersionTuple(5, 8);
       } else if (version == "6.0") {
         runtimeCompatibilityVersion = llvm::VersionTuple(6, 0);
+      } else if (version == "6.2") {
+        runtimeCompatibilityVersion = llvm::VersionTuple(6, 2);
       } else {
         Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
                        versionArg->getAsString(Args), version);
@@ -3694,10 +3844,6 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
 
   Opts.InternalizeSymbols = FrontendOpts.Static;
 
-  if (Args.hasArg(OPT_mergeable_symbols)) {
-    Opts.MergeableSymbols = true;
-  }
-
   if (Args.hasArg(OPT_disable_preallocated_instantiation_caches)) {
     Opts.NoPreallocatedInstantiationCaches = true;
   }
@@ -3765,10 +3911,15 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
     Args.hasFlag(OPT_enable_async_frame_push_pop_metadata,
                  OPT_disable_async_frame_push_pop_metadata,
                  Opts.EmitAsyncFramePushPopMetadata);
+
+  bool platformSupportsTypedMalloc = !llvm::Triple(Triple).isOSLinux() &&
+    !llvm::Triple(Triple).isOSWindows();
+
   Opts.EmitTypeMallocForCoroFrame =
   Args.hasFlag(OPT_enable_emit_type_malloc_for_coro_frame,
               OPT_disable_emit_type_malloc_for_coro_frame,
-              Opts.EmitTypeMallocForCoroFrame);
+              (Opts.EmitTypeMallocForCoroFrame && platformSupportsTypedMalloc));
+
   Opts.AsyncFramePointerAll = Args.hasFlag(OPT_enable_async_frame_pointer_all,
                                            OPT_disable_async_frame_pointer_all,
                                            Opts.AsyncFramePointerAll);
@@ -3829,6 +3980,10 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
 
   Opts.DebugCallsiteInfo |= Args.hasArg(OPT_debug_callsite_info);
 
+  if (Args.hasArg(OPT_mergeable_symbols))
+    Diags.diagnose(SourceLoc(), diag::warn_flag_deprecated,
+                   "-mergeable-symbols");
+
   return false;
 }
 
@@ -4022,6 +4177,7 @@ bool CompilerInvocation::parseArgs(
   }
 
   updateRuntimeLibraryPaths(SearchPathOpts, FrontendOpts, LangOpts);
+  updateImplicitFrameworkSearchPaths(SearchPathOpts, LangOpts);
   setDefaultPrebuiltCacheIfNecessary();
   setDefaultBlocklistsIfNecessary();
   setDefaultInProcessPluginServerPathIfNecessary();
@@ -4030,19 +4186,20 @@ bool CompilerInvocation::parseArgs(
   setIRGenOutputOptsFromFrontendOptions(IRGenOpts, FrontendOpts);
   setBridgingHeaderFromFrontendOptions(ClangImporterOpts, FrontendOpts);
   computeCXXStdlibOptions();
+  computeAArch64TBIOptions();
+
   if (LangOpts.hasFeature(Feature::Embedded)) {
     IRGenOpts.InternalizeAtLink = true;
     IRGenOpts.DisableLegacyTypeInfo = true;
     IRGenOpts.ReflectionMetadata = ReflectionMetadataMode::None;
     IRGenOpts.EnableReflectionNames = false;
     FrontendOpts.DisableBuildingInterface = true;
+    SearchPathOpts.ModuleLoadMode = ModuleLoadingMode::OnlySerialized;
     TypeCheckerOpts.SkipFunctionBodies = FunctionBodySkipping::None;
     SILOpts.SkipFunctionBodies = FunctionBodySkipping::None;
     SILOpts.CMOMode = CrossModuleOptimizationMode::Everything;
     SILOpts.EmbeddedSwift = true;
     SILOpts.UseAggressiveReg2MemForCodeSize = true;
-    // OSSA modules are required for deinit de-virtualization.
-    SILOpts.EnableOSSAModules = true;
     // -g is promoted to -gdwarf-types in embedded Swift
     if (IRGenOpts.DebugInfoLevel == IRGenDebugInfoLevel::ASTTypes) {
       IRGenOpts.DebugInfoLevel = IRGenDebugInfoLevel::DwarfTypes;
@@ -4095,7 +4252,6 @@ CompilerInvocation::loadFromSerializedAST(StringRef data) {
   serialization::ValidationInfo info =
       serialization::validateSerializedAST(
         data,
-        getSILOptions().EnableOSSAModules,
         LangOpts.SDKName,
         &extendedInfo);
 
@@ -4133,7 +4289,6 @@ CompilerInvocation::setUpInputForSILTool(
 
   auto result = serialization::validateSerializedAST(
       fileBufOrErr.get()->getBuffer(),
-      getSILOptions().EnableOSSAModules,
       LangOpts.SDKName,
       &extendedInfo);
   bool hasSerializedAST = result.status == serialization::Status::Valid;
diff --git a/lib/Frontend/DependencyVerifier.cpp b/lib/Frontend/DependencyVerifier.cpp
index 3d0376bf2a752..2d1ef88266d78 100644
--- a/lib/Frontend/DependencyVerifier.cpp
+++ b/lib/Frontend/DependencyVerifier.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2020 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -316,7 +316,7 @@ class DependencyVerifier {
   InFlightDiagnostic
   diagnose(DiagnosticEngine &Diags, const char *LocPtr, Diag<ArgTypes...> ID,
            typename detail::PassArgument<ArgTypes>::type... Args) const {
-    auto Loc = SourceLoc(llvm::SMLoc::getFromPointer(LocPtr));
+    auto Loc = SourceLoc::getFromPointer(LocPtr);
     return Diags.diagnose(Loc, ID, std::move(Args)...);
   }
 };
@@ -486,7 +486,7 @@ bool DependencyVerifier::diagnoseUnfulfilledObligations(
     // HACK: Diagnosing the end of the buffer will print a carat pointing
     // at the file path, but not print any of the buffer's contents, which
     // might be misleading.
-    auto Loc = SourceLoc(llvm::SMLoc::getFromPointer(InputFile.end()));
+    auto Loc = SourceLoc::getFromPointer(InputFile.end());
     switch (p.getKind()) {
     case Expectation::Kind::Negative:
       llvm_unreachable("Obligations may not be negative; only Expectations!");
diff --git a/lib/Frontend/DiagnosticVerifier.cpp b/lib/Frontend/DiagnosticVerifier.cpp
index 953c0eb27bb77..42346c5d869fb 100644
--- a/lib/Frontend/DiagnosticVerifier.cpp
+++ b/lib/Frontend/DiagnosticVerifier.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/Frontend/DiagnosticVerifier.h"
+#include "swift/AST/DiagnosticsFrontend.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/ColorUtils.h"
 #include "swift/Basic/SourceManager.h"
@@ -28,6 +29,8 @@
 
 using namespace swift;
 
+const DiagnosticKind DiagnosticKindExpansion = DiagnosticKind((int)DiagnosticKind::Note + 1);
+
 namespace {
 
 struct ExpectedCheckMatchStartParser {
@@ -67,6 +70,13 @@ struct ExpectedCheckMatchStartParser {
       return true;
     }
 
+    if (MatchStart.starts_with("expansion")) {
+      ClassificationStartLoc = MatchStart.data();
+      ExpectedClassification = DiagnosticKindExpansion;
+      MatchStart = MatchStart.substr(strlen("expansion"));
+      return true;
+    }
+
     return false;
   }
 
@@ -202,6 +212,7 @@ struct ExpectedDiagnosticInfo {
   std::string MessageStr;
   unsigned LineNo = ~0U;
   std::optional<unsigned> ColumnNo;
+  std::optional<unsigned> TargetBufferID;
 
   using AlternativeExpectedFixIts = std::vector<ExpectedFixIt>;
   std::vector<AlternativeExpectedFixIts> Fixits = {};
@@ -220,6 +231,8 @@ struct ExpectedDiagnosticInfo {
   };
   std::optional<ExpectedDocumentationFile> DocumentationFile;
 
+  std::vector<ExpectedDiagnosticInfo> NestedDiags = {};
+
   ExpectedDiagnosticInfo(const char *ExpectedStart,
                          const char *ClassificationStart,
                          const char *ClassificationEnd,
@@ -238,6 +251,8 @@ static std::string getDiagKindString(DiagnosticKind Kind) {
     return "note";
   case DiagnosticKind::Remark:
     return "remark";
+  case DiagnosticKindExpansion:
+    return "expansion";
   }
 
   llvm_unreachable("Unhandled DiagKind in switch.");
@@ -258,7 +273,7 @@ renderDocumentationFile(const std::string &documentationFile) {
 /// Otherwise return \c CapturedDiagnostics.end() with \c false.
 static std::tuple<std::vector<CapturedDiagnosticInfo>::iterator, bool>
 findDiagnostic(std::vector<CapturedDiagnosticInfo> &CapturedDiagnostics,
-               const ExpectedDiagnosticInfo &Expected, unsigned BufferID) {
+               const ExpectedDiagnosticInfo &Expected, unsigned BufferID, SourceManager &SM) {
   auto fallbackI = CapturedDiagnostics.end();
 
   for (auto I = CapturedDiagnostics.begin(), E = CapturedDiagnostics.end();
@@ -385,6 +400,49 @@ bool DiagnosticVerifier::verifyUnknown(
     auto diag = SM.GetMessage({}, llvm::SourceMgr::DK_Error, Message, {}, {});
     printDiagnostic(diag);
   }
+
+  if (HadError) {
+    auto NoteMessage = "use '-verify-ignore-unknown' to "
+                       "ignore diagnostics at this location";
+    auto noteDiag =
+        SM.GetMessage({}, llvm::SourceMgr::DK_Note, NoteMessage, {}, {});
+    printDiagnostic(noteDiag);
+  }
+  return HadError;
+}
+
+bool DiagnosticVerifier::verifyUnrelated(
+    std::vector<CapturedDiagnosticInfo> &CapturedDiagnostics) const {
+  bool HadError = false;
+  for (unsigned i = 0, e = CapturedDiagnostics.size(); i != e; ++i) {
+    SourceLoc Loc = CapturedDiagnostics[i].Loc;
+    if (!Loc.isValid())
+      // checked by verifyUnknown
+      continue;
+
+    HadError = true;
+    std::string Message =
+        ("unexpected " +
+         getDiagKindString(CapturedDiagnostics[i].Classification) +
+         " produced: " + CapturedDiagnostics[i].Message)
+            .str();
+
+    auto diag = SM.GetMessage(Loc, llvm::SourceMgr::DK_Error, Message, {}, {});
+    printDiagnostic(diag);
+
+    auto FileName = SM.getIdentifierForBuffer(SM.findBufferContainingLoc(Loc));
+    auto noteDiag =
+        SM.GetMessage(Loc, llvm::SourceMgr::DK_Note,
+                      ("file '" + FileName +
+                       "' is not parsed for 'expected' statements. Use "
+                       "'-verify-additional-file " +
+                       FileName +
+                       "' to enable, or '-verify-ignore-unrelated' to "
+                       "ignore diagnostics in this file"),
+                      {}, {});
+    printDiagnostic(noteDiag);
+  }
+
   return HadError;
 }
 
@@ -417,7 +475,20 @@ void DiagnosticVerifier::printDiagnostic(const llvm::SMDiagnostic &Diag) const {
   raw_ostream &stream = llvm::errs();
   ColoredStream coloredStream{stream};
   raw_ostream &out = UseColor ? coloredStream : stream;
-  SM.getLLVMSourceMgr().PrintMessage(out, Diag);
+  llvm::SourceMgr &Underlying = SM.getLLVMSourceMgr();
+  Underlying.PrintMessage(out, Diag);
+
+  SourceLoc Loc = SourceLoc::getFromPointer(Diag.getLoc().getPointer());
+  if (Loc.isInvalid())
+    return;
+  unsigned BufferID = SM.findBufferContainingLoc(Loc);
+  if (const GeneratedSourceInfo *GSI = SM.getGeneratedSourceInfo(BufferID)) {
+    SourceLoc ParentLoc = GSI->originalSourceRange.getStart();
+    if (ParentLoc.isInvalid())
+      return;
+    printDiagnostic(SM.GetMessage(ParentLoc, llvm::SourceMgr::DK_Note,
+                                  "in expansion from here", {}, {}));
+  }
 }
 
 std::string
@@ -464,9 +535,9 @@ DiagnosticVerifier::renderFixits(ArrayRef<CapturedFixItInfo> ActualFixIts,
 ///
 /// \param DiagnosticLineNo The line number of the associated expected
 /// diagnostic; used to turn line offsets into line numbers.
-static std::optional<LineColumnRange> parseExpectedFixItRange(
-    StringRef &Str, unsigned DiagnosticLineNo,
-    llvm::function_ref<void(const char *, const Twine &)> diagnoseError) {
+std::optional<LineColumnRange>
+DiagnosticVerifier::parseExpectedFixItRange(StringRef &Str,
+                                            unsigned DiagnosticLineNo) {
   assert(!Str.empty());
 
   struct ParsedLineAndColumn {
@@ -496,10 +567,10 @@ static std::optional<LineColumnRange> parseExpectedFixItRange(
     unsigned FirstVal = 0;
     if (Str.consumeInteger(10, FirstVal)) {
       if (LineOffsetKind == OffsetKind::None) {
-        diagnoseError(Str.data(),
+        addError(Str.data(),
                       "expected line or column number in fix-it verification");
       } else {
-        diagnoseError(Str.data(),
+        addError(Str.data(),
                       "expected line offset after leading '+' or '-' in fix-it "
                       "verification");
       }
@@ -513,7 +584,7 @@ static std::optional<LineColumnRange> parseExpectedFixItRange(
         return ParsedLineAndColumn{std::nullopt, FirstVal};
       }
 
-      diagnoseError(Str.data(),
+      addError(Str.data(),
                     "expected colon-separated column number after line offset "
                     "in fix-it verification");
       return std::nullopt;
@@ -522,7 +593,7 @@ static std::optional<LineColumnRange> parseExpectedFixItRange(
     unsigned Column = 0;
     Str = Str.drop_front();
     if (Str.consumeInteger(10, Column)) {
-      diagnoseError(Str.data(),
+      addError(Str.data(),
                     "expected column number after ':' in fix-it verification");
       return std::nullopt;
     }
@@ -555,7 +626,7 @@ static std::optional<LineColumnRange> parseExpectedFixItRange(
   if (!Str.empty() && Str.front() == '-') {
     Str = Str.drop_front();
   } else {
-    diagnoseError(Str.data(),
+    addError(Str.data(),
                   "expected '-' range separator in fix-it verification");
     return std::nullopt;
   }
@@ -593,319 +664,375 @@ static void validatePrefixList(ArrayRef<std::string> prefixes) {
   }
 }
 
-/// After the file has been processed, check to see if we got all of
-/// the expected diagnostics and check to see if there were any unexpected
-/// ones.
-DiagnosticVerifier::Result DiagnosticVerifier::verifyFile(unsigned BufferID) {
-  using llvm::SMLoc;
-  
+static bool parseTargetBufferName(StringRef &MatchStart, StringRef &Out, size_t &TextStartIdx) {
+  StringRef Offs = MatchStart.slice(0, TextStartIdx);
+
+  size_t LineIndex = Offs.find(':');
+  if (LineIndex == 0 || LineIndex == StringRef::npos)
+    return false;
+  Out = Offs.slice(1, LineIndex);
+  MatchStart = MatchStart.substr(LineIndex);
+  TextStartIdx -= LineIndex;
+  return true;
+}
+
+unsigned DiagnosticVerifier::parseExpectedDiagInfo(
+    unsigned BufferID, StringRef MatchStartIn,
+    unsigned &PrevExpectedContinuationLine,
+    ExpectedDiagnosticInfo &Expected) {
   const SourceLoc BufferStartLoc = SM.getLocForBufferStart(BufferID);
   StringRef InputFile = SM.getEntireTextForBuffer(BufferID);
 
-  // Queue up all of the diagnostics, allowing us to sort them and emit them in
-  // file order.
-  std::vector<llvm::SMDiagnostic> Errors;
-
-  unsigned PrevExpectedContinuationLine = 0;
+  StringRef MatchStart = MatchStartIn;
+  const char *DiagnosticLoc = MatchStart.data();
+  MatchStart = MatchStart.substr(strlen("expected-"));
 
-  std::vector<ExpectedDiagnosticInfo> ExpectedDiagnostics;
+  const char *ClassificationStartLoc = nullptr;
+  std::optional<DiagnosticKind> ExpectedClassification;
+  {
+    ExpectedCheckMatchStartParser parser(MatchStart);
+    // If we fail to parse... continue.
+    if (!parser.parse(AdditionalExpectedPrefixes)) {
+      return 0;
+    }
+    MatchStart = parser.MatchStart;
+    ClassificationStartLoc = parser.ClassificationStartLoc;
+    ExpectedClassification = parser.ExpectedClassification;
+  }
+  assert(ClassificationStartLoc);
+  assert(bool(ExpectedClassification));
+
+  // Skip any whitespace before the {{.
+  MatchStart = MatchStart.substr(MatchStart.find_first_not_of(" \t"));
+
+  size_t TextStartIdx = MatchStart.find("{{");
+  if (TextStartIdx >=
+      MatchStart.find("\n")) { // Either not found, or found beyond next \n
+    addError(MatchStart.data(),
+             "expected {{ in expected-warning/note/error/expansion line");
+    return 0;
+  }
 
-  auto addError = [&](const char *Loc, const Twine &message,
-                      ArrayRef<llvm::SMFixIt> FixIts = {}) {
-    auto loc = SourceLoc(SMLoc::getFromPointer(Loc));
-    auto diag = SM.GetMessage(loc, llvm::SourceMgr::DK_Error, message,
-                              {}, FixIts);
-    Errors.push_back(diag);
-  };
+  Expected = ExpectedDiagnosticInfo(DiagnosticLoc, ClassificationStartLoc,
+                                  /*ClassificationEndLoc=*/MatchStart.data(),
+                                  *ExpectedClassification);
+  int LineOffset = 0;
+  bool AbsoluteLine = false;
+
+  if (TextStartIdx > 0 && MatchStart[0] == '@') {
+    if (MatchStart[1] != '+' && MatchStart[1] != '-' && MatchStart[1] != ':' && (MatchStart[1] < '0' || MatchStart[1] > '9')) {
+      StringRef TargetBufferName;
+      if (!parseTargetBufferName(MatchStart, TargetBufferName, TextStartIdx)) {
+        addError(MatchStart.data(), "expected '+'/'-' for line offset, ':' "
+                                    "for column, or a buffer name");
+        return 0;
+      }
+      Expected.TargetBufferID = SM.getIDForBufferIdentifier(TargetBufferName);
+      if (!Expected.TargetBufferID) {
+        addError(MatchStart.data(),
+                 "no buffer with name '" + TargetBufferName + "' found");
+        return 0;
+      }
+      if (MatchStart[0] != ':' || MatchStart[1] < '0' || MatchStart[1] > '9') {
+        addError(MatchStart.data(),
+                 "expected absolute line number for diagnostic in other buffer");
+        return 0;
+      }
+    }
+    StringRef Offs;
+    if (MatchStart[1] == '+')
+      Offs = MatchStart.slice(2, TextStartIdx).rtrim();
+    else {
+      Offs = MatchStart.slice(1, TextStartIdx).rtrim();
+      if (Offs[0] >= '0' && Offs[0] <= '9')
+        AbsoluteLine = true;
+    }
 
-  // Validate that earlier prefixes are not prefixes of alter
-  // prefixes... otherwise, we will never pattern match the later prefix.
-  validatePrefixList(AdditionalExpectedPrefixes);
+    size_t SpaceIndex = Offs.find(' ');
+    if (SpaceIndex != StringRef::npos && SpaceIndex < TextStartIdx) {
+      size_t Delta = Offs.size() - SpaceIndex;
+      MatchStart = MatchStart.substr(TextStartIdx - Delta);
+      TextStartIdx = Delta;
+      Offs = Offs.slice(0, SpaceIndex);
+    } else {
+      MatchStart = MatchStart.substr(TextStartIdx);
+      TextStartIdx = 0;
+    }
 
-  // Scan the memory buffer looking for expected-note/warning/error.
-  for (size_t Match = InputFile.find("expected-");
-       Match != StringRef::npos; Match = InputFile.find("expected-", Match+1)) {
-    // Process this potential match.  If we fail to process it, just move on to
-    // the next match.
-    StringRef MatchStart = InputFile.substr(Match);
-    const char *DiagnosticLoc = MatchStart.data();
-    MatchStart = MatchStart.substr(strlen("expected-"));
-
-    const char *ClassificationStartLoc = nullptr;
-    std::optional<DiagnosticKind> ExpectedClassification;
-    {
-      ExpectedCheckMatchStartParser parser(MatchStart);
-      // If we fail to parse... continue.
-      if (!parser.parse(AdditionalExpectedPrefixes)) {
-        continue;
+    size_t ColonIndex = Offs.find(':');
+    // Check whether a line offset was provided
+    if (ColonIndex != 0) {
+      StringRef LineOffs = Offs.slice(0, ColonIndex);
+      if (LineOffs.getAsInteger(10, LineOffset)) {
+        addError(MatchStart.data(), "expected line offset before '{{'");
+        return 0;
       }
-      MatchStart = parser.MatchStart;
-      ClassificationStartLoc = parser.ClassificationStartLoc;
-      ExpectedClassification = parser.ExpectedClassification;
     }
-    assert(ClassificationStartLoc);
-    assert(bool(ExpectedClassification));
-
-    // Skip any whitespace before the {{.
-    MatchStart = MatchStart.substr(MatchStart.find_first_not_of(" \t"));
 
-    size_t TextStartIdx = MatchStart.find("{{");
-    if (TextStartIdx >=
-        MatchStart.find("\n")) { // Either not found, or found beyond next \n
-      addError(MatchStart.data(),
-               "expected {{ in expected-warning/note/error line");
-      continue;
+    // Check whether a column was provided
+    if (ColonIndex != StringRef::npos) {
+      Offs = Offs.slice(ColonIndex + 1, Offs.size());
+      int Column = 0;
+      if (Offs.getAsInteger(10, Column)) {
+        addError(MatchStart.data(), "expected column before '{{'");
+        return 0;
+      }
+      Expected.ColumnNo = Column;
     }
+  }
 
-    ExpectedDiagnosticInfo Expected(DiagnosticLoc, ClassificationStartLoc,
-                                    /*ClassificationEndLoc=*/MatchStart.data(),
-                                    *ExpectedClassification);
-    int LineOffset = 0;
+  if (Expected.Classification == DiagnosticKindExpansion && !Expected.ColumnNo.has_value()) {
+    addError(DiagnosticLoc, "expected-expansion requires column location");
+    return 0;
+  }
 
-    if (TextStartIdx > 0 && MatchStart[0] == '@') {
-      if (MatchStart[1] != '+' && MatchStart[1] != '-' &&
-          MatchStart[1] != ':') {
-        addError(MatchStart.data(),
-                 "expected '+'/'-' for line offset, or ':' for column");
-        continue;
+  unsigned Count = 1;
+  if (TextStartIdx > 0) {
+    StringRef CountStr = MatchStart.substr(0, TextStartIdx).trim(" \t");
+    if (CountStr == "*") {
+      Expected.mayAppear = true;
+    } else {
+      if (CountStr.getAsInteger(10, Count)) {
+        addError(MatchStart.data(), "expected match count before '{{'");
+        return 0;
       }
-      StringRef Offs;
-      if (MatchStart[1] == '+')
-        Offs = MatchStart.slice(2, TextStartIdx).rtrim();
-      else
-        Offs = MatchStart.slice(1, TextStartIdx).rtrim();
-
-      size_t SpaceIndex = Offs.find(' ');
-      if (SpaceIndex != StringRef::npos && SpaceIndex < TextStartIdx) {
-        size_t Delta = Offs.size() - SpaceIndex;
-        MatchStart = MatchStart.substr(TextStartIdx - Delta);
-        TextStartIdx = Delta;
-        Offs = Offs.slice(0, SpaceIndex);
-      } else {
-        MatchStart = MatchStart.substr(TextStartIdx);
-        TextStartIdx = 0;
+      if (Count == 0) {
+        addError(MatchStart.data(),
+                 "expected positive match count before '{{'");
+        return 0;
       }
+    }
 
-      size_t ColonIndex = Offs.find(':');
-      // Check whether a line offset was provided
-      if (ColonIndex != 0) {
-        StringRef LineOffs = Offs.slice(0, ColonIndex);
-        if (LineOffs.getAsInteger(10, LineOffset)) {
-          addError(MatchStart.data(), "expected line offset before '{{'");
-          continue;
-        }
-      }
+    // Resync up to the '{{'.
+    MatchStart = MatchStart.substr(TextStartIdx);
+  }
 
-      // Check whether a column was provided
-      if (ColonIndex != StringRef::npos) {
-        Offs = Offs.slice(ColonIndex + 1, Offs.size());
-        int Column = 0;
-        if (Offs.getAsInteger(10, Column)) {
-          addError(MatchStart.data(), "expected column before '{{'");
-          continue;
-        }
-        Expected.ColumnNo = Column;
+  size_t End = StringRef::npos;
+  if (Expected.Classification == DiagnosticKindExpansion) {
+    size_t NestedMatch = MatchStart.find("expected-");
+    // Scan the memory buffer looking for expected-note/warning/error.
+    while (NestedMatch != StringRef::npos) {
+      StringRef NestedMatchStart = MatchStart.substr(NestedMatch);
+      ExpectedDiagnosticInfo NestedExpected(nullptr, nullptr, nullptr,
+                                      DiagnosticKind(-1));
+      unsigned NestedCount =
+          parseExpectedDiagInfo(BufferID, NestedMatchStart,
+                                PrevExpectedContinuationLine, NestedExpected);
+
+      size_t PrevMatchEnd = NestedMatch + 1;
+      if (NestedCount > 0) {
+        // Add the diagnostic the expected number of times.
+        for (; NestedCount; --NestedCount)
+          Expected.NestedDiags.push_back(NestedExpected);
+        size_t NestedMatchEnd =
+            NestedExpected.ExpectedEnd - NestedMatchStart.data();
+        assert(NestedMatchEnd > 0);
+        PrevMatchEnd = NestedMatch + NestedMatchEnd;
       }
-    }
 
-    unsigned Count = 1;
-    if (TextStartIdx > 0) {
-      StringRef CountStr = MatchStart.substr(0, TextStartIdx).trim(" \t");
-      if (CountStr == "*") {
-        Expected.mayAppear = true;
-      } else {
-        if (CountStr.getAsInteger(10, Count)) {
-          addError(MatchStart.data(), "expected match count before '{{'");
-          continue;
-        }
-        if (Count == 0) {
-          addError(MatchStart.data(),
-                   "expected positive match count before '{{'");
-          continue;
-        }
+      size_t NextEnd = MatchStart.find("}}", PrevMatchEnd);
+      NestedMatch = MatchStart.find("expected-", PrevMatchEnd);
+      if (NextEnd < NestedMatch) {
+        End = NextEnd;
+        break;
       }
-
-      // Resync up to the '{{'.
-      MatchStart = MatchStart.substr(TextStartIdx);
     }
 
-    size_t End = MatchStart.find("}}");
     if (End == StringRef::npos) {
-      addError(MatchStart.data(),
+      addError(
+          DiagnosticLoc,
+          "didn't find '}}' to match '{{' in expected-expansion");
+      return 0;
+    }
+    if (Expected.NestedDiags.size() == 0) {
+      addError(DiagnosticLoc, "expected-expansion block is empty");
+      // Keep going
+    }
+  } else {
+    End = MatchStart.find("}}");
+    if (End == StringRef::npos) {
+      addError(
+          MatchStart.data(),
           "didn't find '}}' to match '{{' in expected-warning/note/error line");
-      continue;
+      return 0;
     }
+  }
 
-    llvm::SmallString<256> Buf;
-    Expected.MessageRange = MatchStart.slice(2, End);
-    Expected.MessageStr =
-        Lexer::getEncodedStringSegment(Expected.MessageRange, Buf).str();
-    if (PrevExpectedContinuationLine)
-      Expected.LineNo = PrevExpectedContinuationLine;
-    else
-      Expected.LineNo = SM.getLineAndColumnInBuffer(
-                              BufferStartLoc.getAdvancedLoc(MatchStart.data() -
-                                                            InputFile.data()),
-                              BufferID)
-                            .first;
-    Expected.LineNo += LineOffset;
-
-    // Check if the next expected diagnostic should be in the same line.
-    StringRef AfterEnd = MatchStart.substr(End + strlen("}}"));
-    AfterEnd = AfterEnd.substr(AfterEnd.find_first_not_of(" \t"));
-    if (AfterEnd.starts_with("\\"))
-      PrevExpectedContinuationLine = Expected.LineNo;
-    else
-      PrevExpectedContinuationLine = 0;
-
-    
-    // Scan for fix-its: {{10-14=replacement text}}
-    bool startNewAlternatives = true;
-    StringRef ExtraChecks = MatchStart.substr(End+2).ltrim(" \t");
-    while (ExtraChecks.starts_with("{{")) {
-      // First make sure we have a closing "}}".
-      size_t EndIndex = ExtraChecks.find("}}");
-      if (EndIndex == StringRef::npos) {
-        addError(ExtraChecks.data(),
-                 "didn't find '}}' to match '{{' in diagnostic verification");
-        break;
-      }
-
-      // Allow for close braces to appear in the replacement text.
-      while (EndIndex + 2 < ExtraChecks.size() &&
-             ExtraChecks[EndIndex + 2] == '}')
-        ++EndIndex;
+  llvm::SmallString<256> Buf;
+  Expected.MessageRange = MatchStart.slice(2, End);
+  Expected.MessageStr =
+      Lexer::getEncodedStringSegment(Expected.MessageRange, Buf).str();
+  if (AbsoluteLine)
+    Expected.LineNo = 0;
+  else if (PrevExpectedContinuationLine)
+    Expected.LineNo = PrevExpectedContinuationLine;
+  else
+    Expected.LineNo =
+        SM.getLineAndColumnInBuffer(BufferStartLoc.getAdvancedLoc(
+                                        MatchStart.data() - InputFile.data()),
+                                    BufferID)
+            .first;
+  Expected.LineNo += LineOffset;
+
+  // Check if the next expected diagnostic should be in the same line.
+  StringRef AfterEnd = MatchStart.substr(End + strlen("}}"));
+  AfterEnd = AfterEnd.substr(AfterEnd.find_first_not_of(" \t"));
+  if (AfterEnd.starts_with("\\"))
+    PrevExpectedContinuationLine = Expected.LineNo;
+  else
+    PrevExpectedContinuationLine = 0;
+
+  // Scan for fix-its: {{10-14=replacement text}}
+  bool startNewAlternatives = true;
+  StringRef ExtraChecks = MatchStart.substr(End + 2).ltrim(" \t");
+  while (ExtraChecks.starts_with("{{")) {
+    // First make sure we have a closing "}}".
+    size_t EndIndex = ExtraChecks.find("}}");
+    if (EndIndex == StringRef::npos) {
+      addError(ExtraChecks.data(),
+               "didn't find '}}' to match '{{' in diagnostic verification");
+      break;
+    }
 
-      const char *OpenLoc = ExtraChecks.data(); // Beginning of opening '{{'.
-      const char *CloseLoc =
-          ExtraChecks.data() + EndIndex + 2; // End of closing '}}'.
+    // Allow for close braces to appear in the replacement text.
+    while (EndIndex + 2 < ExtraChecks.size() &&
+           ExtraChecks[EndIndex + 2] == '}')
+      ++EndIndex;
 
-      StringRef CheckStr = ExtraChecks.slice(2, EndIndex);
-      // Check for matching a later "}}" on a different line.
-      if (CheckStr.find_first_of("\r\n") != StringRef::npos) {
-        addError(ExtraChecks.data(), "didn't find '}}' to match '{{' in "
-                                     "diagnostic verification");
-        break;
-      }
+    const char *OpenLoc = ExtraChecks.data(); // Beginning of opening '{{'.
+    const char *CloseLoc =
+        ExtraChecks.data() + EndIndex + 2; // End of closing '}}'.
 
-      // Prepare for the next round of checks.
-      ExtraChecks = ExtraChecks.substr(EndIndex + 2).ltrim(" \t");
-
-      // Handle fix-it alternation.
-      // If two fix-its are separated by `||`, we can match either of the two.
-      // This is represented by putting them in the same subarray of `Fixits`.
-      // If they are not separated by `||`, we must match both of them.
-      // This is represented by putting them in separate subarrays of `Fixits`.
-      if (startNewAlternatives &&
-          (Expected.Fixits.empty() || !Expected.Fixits.back().empty()))
-        Expected.Fixits.push_back({});
-
-      if (ExtraChecks.starts_with("||")) {
-        startNewAlternatives = false;
-        ExtraChecks = ExtraChecks.substr(2).ltrim(" \t");
-      } else {
-        startNewAlternatives = true;
-      }
+    StringRef CheckStr = ExtraChecks.slice(2, EndIndex);
+    // Check for matching a later "}}" on a different line.
+    if (CheckStr.find_first_of("\r\n") != StringRef::npos) {
+      addError(ExtraChecks.data(), "didn't find '}}' to match '{{' in "
+                                   "diagnostic verification");
+      break;
+    }
 
-      // If this check starts with 'documentation-file=', check for a
-      // documentation file name instead of a fix-it.
-      if (CheckStr.starts_with(categoryDocFileSpecifier)) {
-        if (Expected.DocumentationFile.has_value()) {
-          addError(CheckStr.data(),
-                   "each verified diagnostic may only have one "
-                   "{{documentation-file=<#notes#>}} declaration");
-          continue;
-        }
+    // Prepare for the next round of checks.
+    ExtraChecks = ExtraChecks.substr(EndIndex + 2).ltrim(" \t");
+
+    // Handle fix-it alternation.
+    // If two fix-its are separated by `||`, we can match either of the two.
+    // This is represented by putting them in the same subarray of `Fixits`.
+    // If they are not separated by `||`, we must match both of them.
+    // This is represented by putting them in separate subarrays of `Fixits`.
+    if (startNewAlternatives &&
+        (Expected.Fixits.empty() || !Expected.Fixits.back().empty()))
+      Expected.Fixits.push_back({});
+
+    if (ExtraChecks.starts_with("||")) {
+      startNewAlternatives = false;
+      ExtraChecks = ExtraChecks.substr(2).ltrim(" \t");
+    } else {
+      startNewAlternatives = true;
+    }
 
-        // Trim 'documentation-file='.
-        StringRef name = CheckStr.substr(categoryDocFileSpecifier.size());
-        Expected.DocumentationFile = { OpenLoc, CloseLoc, name };
+    // If this check starts with 'documentation-file=', check for a
+    // documentation file name instead of a fix-it.
+    if (CheckStr.starts_with(categoryDocFileSpecifier)) {
+      if (Expected.DocumentationFile.has_value()) {
+        addError(CheckStr.data(),
+                 "each verified diagnostic may only have one "
+                 "{{documentation-file=<#notes#>}} declaration");
         continue;
       }
 
-      // This wasn't a documentation file specifier, so it must be a fix-it.
-      // Special case for specifying no fixits should appear.
-      if (CheckStr == fixitExpectationNoneString) {
-        if (Expected.noneMarkerStartLoc) {
-          addError(CheckStr.data() - 2,
-                   Twine("A second {{") + fixitExpectationNoneString +
-                       "}} was found. It may only appear once in an expectation.");
-          break;
-        }
-
-        Expected.noneMarkerStartLoc = CheckStr.data() - 2;
-        continue;
-      }
+      // Trim 'documentation-file='.
+      StringRef name = CheckStr.substr(categoryDocFileSpecifier.size());
+      Expected.DocumentationFile = {OpenLoc, CloseLoc, name};
+      continue;
+    }
 
+    // This wasn't a documentation file specifier, so it must be a fix-it.
+    // Special case for specifying no fixits should appear.
+    if (CheckStr == fixitExpectationNoneString) {
       if (Expected.noneMarkerStartLoc) {
-        addError(Expected.noneMarkerStartLoc, Twine("{{") +
-                                                  fixitExpectationNoneString +
-                                                  "}} must be at the end.");
+        addError(
+            CheckStr.data() - 2,
+            Twine("A second {{") + fixitExpectationNoneString +
+                "}} was found. It may only appear once in an expectation.");
         break;
       }
 
-      if (CheckStr.empty()) {
-        addError(CheckStr.data(), Twine("expected fix-it verification within "
-                                        "braces; example: '1-2=text' or '") +
-                                      fixitExpectationNoneString + Twine("'"));
-        continue;
-      }
+      Expected.noneMarkerStartLoc = CheckStr.data() - 2;
+      continue;
+    }
 
-      // Parse the pieces of the fix-it.
-      ExpectedFixIt FixIt;
-      FixIt.StartLoc = OpenLoc;
-      FixIt.EndLoc = CloseLoc;
+    if (Expected.noneMarkerStartLoc) {
+      addError(Expected.noneMarkerStartLoc, Twine("{{") +
+                                                fixitExpectationNoneString +
+                                                "}} must be at the end.");
+      break;
+    }
 
-      if (const auto range =
-              parseExpectedFixItRange(CheckStr, Expected.LineNo, addError)) {
-        FixIt.Range = range.value();
-      } else {
-        continue;
-      }
+    if (CheckStr.empty()) {
+      addError(CheckStr.data(), Twine("expected fix-it verification within "
+                                      "braces; example: '1-2=text' or '") +
+                                    fixitExpectationNoneString + Twine("'"));
+      continue;
+    }
 
-      if (!CheckStr.empty() && CheckStr.front() == '=') {
-        CheckStr = CheckStr.drop_front();
-      } else {
-        addError(CheckStr.data(),
-                 "expected '=' after range in fix-it verification");
-        continue;
-      }
+    // Parse the pieces of the fix-it.
+    ExpectedFixIt FixIt;
+    FixIt.StartLoc = OpenLoc;
+    FixIt.EndLoc = CloseLoc;
 
-      // Translate literal "\\n" into '\n', inefficiently.
-      for (const char *current = CheckStr.begin(), *end = CheckStr.end();
-           current != end; /* in loop */) {
-        if (*current == '\\' && current + 1 < end) {
-          if (current[1] == 'n') {
-            FixIt.Text += '\n';
-            current += 2;
-          } else {  // Handle \}, \\, etc.
-            FixIt.Text += current[1];
-            current += 2;
-          }
+    if (const auto range =
+            parseExpectedFixItRange(CheckStr, Expected.LineNo)) {
+      FixIt.Range = range.value();
+    } else {
+      continue;
+    }
 
-        } else {
-          FixIt.Text += *current++;
+    if (!CheckStr.empty() && CheckStr.front() == '=') {
+      CheckStr = CheckStr.drop_front();
+    } else {
+      addError(CheckStr.data(),
+               "expected '=' after range in fix-it verification");
+      continue;
+    }
+
+    // Translate literal "\\n" into '\n', inefficiently.
+    for (const char *current = CheckStr.begin(), *end = CheckStr.end();
+         current != end;
+         /* in loop */) {
+      if (*current == '\\' && current + 1 < end) {
+        if (current[1] == 'n') {
+          FixIt.Text += '\n';
+          current += 2;
+        } else { // Handle \}, \\, etc.
+          FixIt.Text += current[1];
+          current += 2;
         }
+
+      } else {
+        FixIt.Text += *current++;
       }
+    }
 
-      Expected.Fixits.back().push_back(FixIt);
+    if (Expected.Classification == DiagnosticKindExpansion) {
+      addError(OpenLoc, "expected-expansion cannot have fixits");
     }
+    Expected.Fixits.back().push_back(FixIt);
+  }
 
-    // If there's a trailing empty alternation, remove it.
-    if (!Expected.Fixits.empty() && Expected.Fixits.back().empty())
-      Expected.Fixits.pop_back();
+  // If there's a trailing empty alternation, remove it.
+  if (!Expected.Fixits.empty() && Expected.Fixits.back().empty())
+    Expected.Fixits.pop_back();
 
-    Expected.ExpectedEnd = ExtraChecks.data();
-    
-    // Don't include trailing whitespace in the expected-foo{{}} range.
-    while (isspace(Expected.ExpectedEnd[-1]))
-      --Expected.ExpectedEnd;
+  Expected.ExpectedEnd = ExtraChecks.data();
 
-    // Add the diagnostic the expected number of times.
-    for (; Count; --Count)
-      ExpectedDiagnostics.push_back(Expected);
-  }
+  // Don't include trailing whitespace in the expected-foo{{}} range.
+  while (isspace(Expected.ExpectedEnd[-1]))
+    --Expected.ExpectedEnd;
+
+  return Count;
+}
 
+void DiagnosticVerifier::verifyDiagnostics(std::vector<ExpectedDiagnosticInfo> &ExpectedDiagnostics, unsigned BufferID) {
   // Make sure all the expected diagnostics appeared.
   std::reverse(ExpectedDiagnostics.begin(), ExpectedDiagnostics.end());
 
@@ -913,9 +1040,24 @@ DiagnosticVerifier::Result DiagnosticVerifier::verifyFile(unsigned BufferID) {
     --i;
     auto &expected = ExpectedDiagnostics[i];
 
+    unsigned ID = expected.TargetBufferID.value_or(BufferID);
     // Check to see if we had this expected diagnostic.
+    if (expected.Classification == DiagnosticKindExpansion) {
+      SourceLoc Loc = SM.getLocForLineCol(BufferID, expected.LineNo, *expected.ColumnNo);
+      if (Expansions.count(Loc) == 0) {
+        addError(expected.ExpectedStart,
+                 "no expansion with diagnostics starting at " +
+                     std::to_string(expected.LineNo) + ":" + std::to_string(*expected.ColumnNo));
+        continue;
+      }
+      unsigned ExpansionBufferID = Expansions[Loc];
+      verifyDiagnostics(expected.NestedDiags, ExpansionBufferID);
+      if (expected.NestedDiags.empty())
+        ExpectedDiagnostics.erase(ExpectedDiagnostics.begin()+i);
+      continue;
+    }
     auto FoundDiagnosticInfo =
-        findDiagnostic(CapturedDiagnostics, expected, BufferID);
+        findDiagnostic(CapturedDiagnostics, expected, ID, SM);
     auto FoundDiagnosticIter = std::get<0>(FoundDiagnosticInfo);
     if (FoundDiagnosticIter == CapturedDiagnostics.end()) {
       // Diagnostic didn't exist.  If this is a 'mayAppear' diagnostic, then
@@ -928,8 +1070,8 @@ DiagnosticVerifier::Result DiagnosticVerifier::verifyFile(unsigned BufferID) {
     auto emitFixItsError = [&](const char *location, const Twine &message,
                                const char *replStartLoc, const char *replEndLoc,
                                const std::string &replStr) {
-      llvm::SMFixIt fix(llvm::SMRange(SMLoc::getFromPointer(replStartLoc),
-                                      SMLoc::getFromPointer(replEndLoc)),
+      llvm::SMFixIt fix(llvm::SMRange(llvm::SMLoc::getFromPointer(replStartLoc),
+                                      llvm::SMLoc::getFromPointer(replEndLoc)),
                         replStr);
       addError(location, message, fix);
     };
@@ -1070,8 +1212,8 @@ DiagnosticVerifier::Result DiagnosticVerifier::verifyFile(unsigned BufferID) {
           // produce a fixit of our own.
           auto actual =
               renderDocumentationFile(FoundDiagnostic.CategoryDocFile);
-          auto replStartLoc = SMLoc::getFromPointer(expectedDocFile->StartLoc);
-          auto replEndLoc = SMLoc::getFromPointer(expectedDocFile->EndLoc);
+          auto replStartLoc = llvm::SMLoc::getFromPointer(expectedDocFile->StartLoc);
+          auto replEndLoc = llvm::SMLoc::getFromPointer(expectedDocFile->EndLoc);
 
           llvm::SMFixIt fix(llvm::SMRange(replStartLoc, replEndLoc), actual);
           addError(expectedDocFile->StartLoc,
@@ -1093,53 +1235,17 @@ DiagnosticVerifier::Result DiagnosticVerifier::verifyFile(unsigned BufferID) {
     else
       ExpectedDiagnostics.erase(ExpectedDiagnostics.begin()+i);
   }
-  
-  // Check to see if we have any incorrect diagnostics.  If so, diagnose them as
-  // such.
-  auto expectedDiagIter = ExpectedDiagnostics.begin();
-  while (expectedDiagIter != ExpectedDiagnostics.end()) {
-    // Check to see if any found diagnostics have the right line and
-    // classification, but the wrong text.
-    auto I = CapturedDiagnostics.begin();
-    for (auto E = CapturedDiagnostics.end(); I != E; ++I) {
-      // Verify the file and line of the diagnostic.
-      if (I->Line != expectedDiagIter->LineNo || I->SourceBufferID != BufferID
-            || I->Classification != expectedDiagIter->Classification)
-        continue;
-      
-      // Otherwise, we found it, break out.
-      break;
-    }
+}
 
-    if (I == CapturedDiagnostics.end()) {
-      ++expectedDiagIter;
+void DiagnosticVerifier::verifyRemaining(
+    std::vector<ExpectedDiagnosticInfo> &ExpectedDiagnostics,
+    const char *FileStart) {
+  std::reverse(ExpectedDiagnostics.begin(), ExpectedDiagnostics.end());
+  for (auto &expected : ExpectedDiagnostics) {
+    if (expected.Classification == DiagnosticKindExpansion) {
+      verifyRemaining(expected.NestedDiags, FileStart);
       continue;
     }
-
-    if (I->Message.find(expectedDiagIter->MessageStr) == StringRef::npos) {
-      auto StartLoc =
-          SMLoc::getFromPointer(expectedDiagIter->MessageRange.begin());
-      auto EndLoc = SMLoc::getFromPointer(expectedDiagIter->MessageRange.end());
-
-      llvm::SMFixIt fixIt(llvm::SMRange{StartLoc, EndLoc}, I->Message);
-      addError(expectedDiagIter->MessageRange.begin(),
-               "incorrect message found", fixIt);
-    } else if (I->Column != *expectedDiagIter->ColumnNo) {
-      // The difference must be only in the column
-      addError(expectedDiagIter->MessageRange.begin(),
-               llvm::formatv("message found at column {0} but was expected to "
-                             "appear at column {1}",
-                             I->Column, *expectedDiagIter->ColumnNo));
-    } else {
-      llvm_unreachable("unhandled difference from expected diagnostic");
-    }
-    CapturedDiagnostics.erase(I);
-    expectedDiagIter = ExpectedDiagnostics.erase(expectedDiagIter);
-  }
-
-  // Diagnose expected diagnostics that didn't appear.
-  std::reverse(ExpectedDiagnostics.begin(), ExpectedDiagnostics.end());
-  for (auto const &expected : ExpectedDiagnostics) {
     std::string message = "expected "+getDiagKindString(expected.Classification)
       + " not produced";
 
@@ -1158,7 +1264,6 @@ DiagnosticVerifier::Result DiagnosticVerifier::verifyFile(unsigned BufferID) {
       EndLoc = expected.ExpectedEnd;
     } else {
       // If we hit the end of line, then zap whitespace leading up to it.
-      auto FileStart = InputFile.data();
       while (StartLoc-1 != FileStart && isspace(StartLoc[-1]) &&
              StartLoc[-1] != '\n' && StartLoc[-1] != '\r')
         --StartLoc;
@@ -1182,19 +1287,127 @@ DiagnosticVerifier::Result DiagnosticVerifier::verifyFile(unsigned BufferID) {
 
     // Remove the expected-foo{{}} as a fixit.
     llvm::SMFixIt fixIt(llvm::SMRange{
-      SMLoc::getFromPointer(StartLoc),
-      SMLoc::getFromPointer(EndLoc)
+      llvm::SMLoc::getFromPointer(StartLoc),
+      llvm::SMLoc::getFromPointer(EndLoc)
     }, "");
     addError(expected.ExpectedStart, message, fixIt);
   }
+}
+
+void DiagnosticVerifier::addError(const char *Loc, const Twine &message,
+                                  ArrayRef<llvm::SMFixIt> FixIts) {
+  auto loc = SourceLoc::getFromPointer(Loc);
+  auto diag =
+      SM.GetMessage(loc, llvm::SourceMgr::DK_Error, message, {}, FixIts);
+  Errors.push_back(diag);
+}
+
+/// After the file has been processed, check to see if we got all of
+/// the expected diagnostics and check to see if there were any unexpected
+/// ones.
+DiagnosticVerifier::Result DiagnosticVerifier::verifyFile(unsigned BufferID) {
+  Errors.clear();
+  using llvm::SMLoc;
+
+  StringRef InputFile = SM.getEntireTextForBuffer(BufferID);
+
+  // Queue up all of the diagnostics, allowing us to sort them and emit them in
+  // file order.
+
+  unsigned PrevExpectedContinuationLine = 0;
+
+  std::vector<ExpectedDiagnosticInfo> ExpectedDiagnostics;
+
+  // Validate that earlier prefixes are not prefixes of alter
+  // prefixes... otherwise, we will never pattern match the later prefix.
+  validatePrefixList(AdditionalExpectedPrefixes);
+
+  const char *PrevMatchEnd = InputFile.data();
+  // Scan the memory buffer looking for expected-note/warning/error.
+  for (size_t Match = InputFile.find("expected-");
+       Match != StringRef::npos; Match = InputFile.find("expected-", Match+1)) {
+    // Process this potential match.  If we fail to process it, just move on to
+    // the next match.
+    StringRef MatchStart = InputFile.substr(Match);
+    if (MatchStart.data() < PrevMatchEnd)
+      continue;
+    ExpectedDiagnosticInfo Expected(nullptr, nullptr, nullptr, DiagnosticKind(-1));
+    unsigned Count = parseExpectedDiagInfo(BufferID, MatchStart, PrevExpectedContinuationLine, Expected);
+    if (Count < 1)
+      continue;
+
+    // Add the diagnostic the expected number of times.
+    for (; Count; --Count)
+      ExpectedDiagnostics.push_back(Expected);
+    PrevMatchEnd = Expected.ExpectedEnd;
+  }
+
+  verifyDiagnostics(ExpectedDiagnostics, BufferID);
+
+  // Check to see if we have any incorrect diagnostics.  If so, diagnose them as
+  // such.
+  auto expectedDiagIter = ExpectedDiagnostics.begin();
+  while (expectedDiagIter != ExpectedDiagnostics.end()) {
+    // Check to see if any found diagnostics have the right line and
+    // classification, but the wrong text.
+    auto I = CapturedDiagnostics.begin();
+    for (auto E = CapturedDiagnostics.end(); I != E; ++I) {
+      // Verify the file and line of the diagnostic.
+      if (I->Line != expectedDiagIter->LineNo || I->SourceBufferID != BufferID
+            || I->Classification != expectedDiagIter->Classification)
+        continue;
+
+      // Otherwise, we found it, break out.
+      break;
+    }
+
+    if (I == CapturedDiagnostics.end()) {
+      ++expectedDiagIter;
+      continue;
+    }
+
+    if (I->Message.find(expectedDiagIter->MessageStr) == StringRef::npos) {
+      auto StartLoc =
+          SMLoc::getFromPointer(expectedDiagIter->MessageRange.begin());
+      auto EndLoc = SMLoc::getFromPointer(expectedDiagIter->MessageRange.end());
+
+      llvm::SMFixIt fixIt(llvm::SMRange{StartLoc, EndLoc}, I->Message);
+      addError(expectedDiagIter->MessageRange.begin(),
+               "incorrect message found", fixIt);
+    } else if (I->Column != *expectedDiagIter->ColumnNo) {
+      // The difference must be only in the column
+      addError(expectedDiagIter->MessageRange.begin(),
+               llvm::formatv("message found at column {0} but was expected to "
+                             "appear at column {1}",
+                             I->Column, *expectedDiagIter->ColumnNo));
+    } else {
+      llvm_unreachable("unhandled difference from expected diagnostic");
+    }
+    CapturedDiagnostics.erase(I);
+    expectedDiagIter = ExpectedDiagnostics.erase(expectedDiagIter);
+  }
+
+  // Diagnose expected diagnostics that didn't appear.
+  verifyRemaining(ExpectedDiagnostics, InputFile.data());
   
   // Verify that there are no diagnostics (in MemoryBuffer) left in the list.
   bool HadUnexpectedDiag = false;
   auto CapturedDiagIter = CapturedDiagnostics.begin();
   while (CapturedDiagIter != CapturedDiagnostics.end()) {
     if (CapturedDiagIter->SourceBufferID != BufferID) {
-      ++CapturedDiagIter;
-      continue;
+      if (!CapturedDiagIter->SourceBufferID) {
+        ++CapturedDiagIter;
+        continue;
+      }
+
+      // Diagnostics attached to generated sources originating in this
+      // buffer also count as part of this buffer for this purpose.
+      const GeneratedSourceInfo *GSI =
+          SM.getGeneratedSourceInfo(CapturedDiagIter->SourceBufferID.value());
+      if (!GSI || llvm::find(GSI->ancestors, BufferID) == GSI->ancestors.end()) {
+        ++CapturedDiagIter;
+        continue;
+      }
     }
 
     HadUnexpectedDiag = true;
@@ -1255,6 +1468,27 @@ void DiagnosticVerifier::printRemainingDiagnostics() const {
   }
 }
 
+static void
+processExpansions(SourceManager &SM, llvm::DenseMap<SourceLoc, unsigned> &Expansions,
+                  std::vector<CapturedDiagnosticInfo> &CapturedDiagnostics) {
+  for (auto &diag : CapturedDiagnostics) {
+    if (!diag.SourceBufferID.has_value())
+      continue;
+    const GeneratedSourceInfo *GSI =
+        SM.getGeneratedSourceInfo(diag.SourceBufferID.value());
+    if (!GSI)
+      continue;
+    SourceLoc ExpansionStart = GSI->originalSourceRange.getStart();
+    if (ExpansionStart.isInvalid())
+      continue;
+    if (Expansions.count(ExpansionStart)) {
+      ASSERT(Expansions[ExpansionStart] == diag.SourceBufferID.value());
+      continue;
+    }
+    Expansions.insert(std::make_pair(ExpansionStart, diag.SourceBufferID.value()));
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // Main entrypoints
 //===----------------------------------------------------------------------===//
@@ -1264,6 +1498,10 @@ void DiagnosticVerifier::printRemainingDiagnostics() const {
 /// file.
 void DiagnosticVerifier::handleDiagnostic(SourceManager &SM,
                                           const DiagnosticInfo &Info) {
+  // Ignore "fatal error encountered while in -verify mode" errors,
+  // because there's no reason to verify them.
+  if (Info.ID == diag::verify_encountered_fatal.ID)
+    return;
   SmallVector<CapturedFixItInfo, 2> fixIts;
   for (const auto &fixIt : Info.FixIts) {
     fixIts.emplace_back(SM, fixIt);
@@ -1309,6 +1547,8 @@ bool DiagnosticVerifier::finishProcessing() {
     }
   }
 
+  processExpansions(SM, Expansions, CapturedDiagnostics);
+
   ArrayRef<unsigned> BufferIDLists[2] = { BufferIDs, additionalBufferIDs };
   for (ArrayRef<unsigned> BufferIDList : BufferIDLists)
     for (auto &BufferID : BufferIDList) {
@@ -1322,6 +1562,11 @@ bool DiagnosticVerifier::finishProcessing() {
     // For <unknown>, all errors are unexpected.
     Result.HadUnexpectedDiag |= HadError;
   }
+  if (!IgnoreUnrelated) {
+    bool HadError = verifyUnrelated(CapturedDiagnostics);
+    Result.HadError |= HadError;
+    Result.HadUnexpectedDiag |= HadError;
+  }
 
   if (Result.HadUnexpectedDiag)
     printRemainingDiagnostics();
diff --git a/lib/Frontend/Frontend.cpp b/lib/Frontend/Frontend.cpp
index b1cf29235c929..159e312732fd3 100644
--- a/lib/Frontend/Frontend.cpp
+++ b/lib/Frontend/Frontend.cpp
@@ -18,6 +18,7 @@
 #include "swift/Frontend/Frontend.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/AvailabilityDomain.h"
+#include "swift/AST/AvailabilityScope.h"
 #include "swift/AST/DiagnosticsFrontend.h"
 #include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/FileSystem.h"
@@ -196,7 +197,8 @@ SerializationOptions CompilerInvocation::computeSerializationOptions(
   serializationOpts.DocOutputPath = outs.ModuleDocOutputPath;
   serializationOpts.SourceInfoOutputPath = outs.ModuleSourceInfoOutputPath;
   serializationOpts.GroupInfoPath = opts.GroupInfoPath.c_str();
-  if (opts.ModuleHasBridgingHeader && !outs.ModuleOutputPath.empty())
+  if (opts.ModuleHasBridgingHeader && !outs.ModuleOutputPath.empty() &&
+      !opts.ImportHeaderAsInternal)
     serializationOpts.SerializeBridgingHeader = true;
   // For batch mode, emit empty header path as placeholder.
   if (serializationOpts.SerializeBridgingHeader &&
@@ -207,7 +209,6 @@ SerializationOptions CompilerInvocation::computeSerializationOptions(
   serializationOpts.ModuleLinkName = opts.ModuleLinkName;
   serializationOpts.UserModuleVersion = opts.UserModuleVersion;
   serializationOpts.AllowableClients = opts.AllowableClients;
-  serializationOpts.SerializeDebugInfoSIL = opts.SerializeDebugInfoSIL;
 
   serializationOpts.PublicDependentLibraries =
       getIRGenOptions().PublicLinkLibraries;
@@ -268,7 +269,17 @@ SerializationOptions CompilerInvocation::computeSerializationOptions(
   serializationOpts.EmbeddedSwiftModule =
       LangOpts.hasFeature(Feature::Embedded);
 
-  serializationOpts.IsOSSA = getSILOptions().EnableOSSAModules;
+  serializationOpts.SerializeDebugInfoSIL = opts.SerializeDebugInfoSIL;
+
+  // Enable serialization of debug info in embedded mode.
+  // This is important to get diagnostics for errors which are located in imported modules.
+  // Such errors can sometimes only be detected when building the client module, because
+  // the error can be in a generic function which is specialized in the client module.
+  if (serializationOpts.EmbeddedSwiftModule &&
+      // Except for the stdlib core. We don't want to get error locations inside stdlib internals.
+      !getParseStdlib()) {
+    serializationOpts.SerializeDebugInfoSIL = true;
+  }
 
   serializationOpts.SkipNonExportableDecls =
       getLangOptions().SkipNonExportableDecls;
@@ -296,6 +307,16 @@ void CompilerInstance::recordPrimaryInputBuffer(unsigned BufID) {
   PrimaryBufferIDs.insert(BufID);
 }
 
+static bool shouldEnableRequestReferenceTracking(const CompilerInstance &CI) {
+  // Enable request reference dependency tracking when we're either writing
+  // dependencies for incremental mode, verifying dependencies, or collecting
+  // stats.
+  auto &opts = CI.getInvocation().getFrontendOptions();
+  return opts.InputsAndOutputs.hasReferenceDependenciesFilePath() ||
+         opts.EnableIncrementalDependencyVerifier ||
+         !opts.StatsOutputDir.empty();
+}
+
 bool CompilerInstance::setUpASTContextIfNeeded() {
   if (FrontendOptions::doesActionBuildModuleFromInterface(
           Invocation.getFrontendOptions().RequestedAction) &&
@@ -306,10 +327,8 @@ bool CompilerInstance::setUpASTContextIfNeeded() {
     return false;
   }
 
-  // For the time being, we only need to record dependencies in batch mode
-  // and single file builds.
-  Invocation.getLangOptions().RecordRequestReferences
-    = !isWholeModuleCompilation();
+  Invocation.getLangOptions().RecordRequestReferences =
+      shouldEnableRequestReferenceTracking(*this);
 
   Context.reset(ASTContext::get(
       Invocation.getLangOptions(), Invocation.getTypeCheckerOptions(),
@@ -415,8 +434,8 @@ bool CompilerInstance::setupDiagnosticVerifierIfNeeded() {
     DiagVerifier = std::make_unique<DiagnosticVerifier>(
         SourceMgr, InputSourceCodeBufferIDs, diagOpts.AdditionalVerifierFiles,
         diagOpts.VerifyMode == DiagnosticOptions::VerifyAndApplyFixes,
-        diagOpts.VerifyIgnoreUnknown, diagOpts.UseColor,
-        diagOpts.AdditionalDiagnosticVerifierPrefixes);
+        diagOpts.VerifyIgnoreUnknown, diagOpts.VerifyIgnoreUnrelated,
+        diagOpts.UseColor, diagOpts.AdditionalDiagnosticVerifierPrefixes);
 
     addDiagnosticConsumer(DiagVerifier.get());
   }
@@ -454,9 +473,14 @@ bool CompilerInstance::setupCASIfNeeded(ArrayRef<const char *> Args) {
     return false;
 
   const auto &Opts = getInvocation().getCASOptions();
-  auto MaybeDB= Opts.CASOpts.getOrCreateDatabases();
+  if (Opts.CASOpts.CASPath.empty() && Opts.CASOpts.PluginPath.empty()) {
+    Diagnostics.diagnose(SourceLoc(), diag::error_cas_initialization,
+                         "no CAS options provided");
+    return true;
+  }
+  auto MaybeDB = Opts.CASOpts.getOrCreateDatabases();
   if (!MaybeDB) {
-    Diagnostics.diagnose(SourceLoc(), diag::error_cas,
+    Diagnostics.diagnose(SourceLoc(), diag::error_cas_initialization,
                          toString(MaybeDB.takeError()));
     return true;
   }
@@ -466,6 +490,7 @@ bool CompilerInstance::setupCASIfNeeded(ArrayRef<const char *> Args) {
   auto BaseKey = createCompileJobBaseCacheKey(*CAS, Args);
   if (!BaseKey) {
     Diagnostics.diagnose(SourceLoc(), diag::error_cas,
+                         "creating base cache key",
                          toString(BaseKey.takeError()));
     return true;
   }
@@ -629,14 +654,12 @@ bool CompilerInstance::setUpVirtualFileSystemOverlays() {
   }
 
   if (Invocation.getCASOptions().requireCASFS()) {
-    if (!CASOpts.CASFSRootIDs.empty() || !CASOpts.ClangIncludeTrees.empty() ||
-        !CASOpts.ClangIncludeTreeFileList.empty()) {
+    if (Invocation.getCASOptions().HasImmutableFileSystem) {
       // Set up CASFS as BaseFS.
-      auto FS = createCASFileSystem(*CAS, CASOpts.CASFSRootIDs,
-                                    CASOpts.ClangIncludeTrees,
+      auto FS = createCASFileSystem(*CAS, CASOpts.ClangIncludeTree,
                                     CASOpts.ClangIncludeTreeFileList);
       if (!FS) {
-        Diagnostics.diagnose(SourceLoc(), diag::error_cas,
+        Diagnostics.diagnose(SourceLoc(), diag::error_cas_fs_creation,
                              toString(FS.takeError()));
         return true;
       }
@@ -681,8 +704,8 @@ bool CompilerInstance::setUpVirtualFileSystemOverlays() {
       }
     }
     llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayVFS =
-        new llvm::vfs::OverlayFileSystem(SourceMgr.getFileSystem());
-    OverlayVFS->pushOverlay(MemFS);
+        new llvm::vfs::OverlayFileSystem(MemFS);
+    OverlayVFS->pushOverlay(SourceMgr.getFileSystem());
     SourceMgr.setFileSystem(std::move(OverlayVFS));
   }
 
@@ -755,16 +778,42 @@ void CompilerInstance::setUpDiagnosticOptions() {
 //    in the presence of overlays and mixed-source frameworks, we want to prefer
 //    the overlay or framework module over the underlying Clang module.
 bool CompilerInstance::setUpModuleLoaders() {
+  auto ModuleCachePathFromInvocation = getInvocation().getClangModuleCachePath();
+  auto &FEOpts = Invocation.getFrontendOptions();
+  auto MLM = Invocation.getSearchPathOptions().ModuleLoadMode;
+  auto IgnoreSourceInfoFile = Invocation.getFrontendOptions().IgnoreSwiftSourceInfo;
+  ModuleInterfaceLoaderOptions LoaderOpts(FEOpts);
+
+  // Dependency scanning sub-invocations only require the loaders necessary
+  // for locating textual and binary Swift modules.
+  if (Invocation.getFrontendOptions().DependencyScanningSubInvocation) {
+    Context->addModuleInterfaceChecker(
+        std::make_unique<ModuleInterfaceCheckerImpl>(
+            *Context, ModuleCachePathFromInvocation, FEOpts.PrebuiltModuleCachePath,
+            FEOpts.BackupModuleInterfaceDir, LoaderOpts));
+
+    if (MLM != ModuleLoadingMode::OnlySerialized) {
+      // We only need ModuleInterfaceLoader for implicit modules.
+      auto PIML = ModuleInterfaceLoader::create(
+          *Context, *static_cast<ModuleInterfaceCheckerImpl*>(Context
+            ->getModuleInterfaceChecker()), getDependencyTracker(), MLM,
+          FEOpts.PreferInterfaceForModules, IgnoreSourceInfoFile);
+      Context->addModuleLoader(std::move(PIML), false, false, true);
+    }
+    std::unique_ptr<ImplicitSerializedModuleLoader> ISML =
+    ImplicitSerializedModuleLoader::create(*Context, getDependencyTracker(), MLM,
+                                   IgnoreSourceInfoFile);
+    this->DefaultSerializedLoader = ISML.get();
+    Context->addModuleLoader(std::move(ISML));
+
+    return false;
+  }
+
   if (hasSourceImport()) {
-    bool enableLibraryEvolution =
-      Invocation.getFrontendOptions().EnableLibraryEvolution;
     Context->addModuleLoader(SourceLoader::create(*Context,
-                                                  enableLibraryEvolution,
                                                   getDependencyTracker()));
   }
-  auto MLM = Invocation.getSearchPathOptions().ModuleLoadMode;
-  auto IgnoreSourceInfoFile =
-    Invocation.getFrontendOptions().IgnoreSwiftSourceInfo;
+
   if (Invocation.getLangOptions().EnableMemoryBufferImporter) {
     auto MemoryBufferLoader = MemoryBufferSerializedModuleLoader::create(
         *Context, getDependencyTracker(), MLM, IgnoreSourceInfoFile);
@@ -781,7 +830,8 @@ bool CompilerInstance::setUpModuleLoaders() {
   if (ExplicitModuleBuild ||
       !Invocation.getSearchPathOptions().ExplicitSwiftModuleMapPath.empty() ||
       !Invocation.getSearchPathOptions().ExplicitSwiftModuleInputs.empty()) {
-    if (Invocation.getCASOptions().EnableCaching)
+    if (Invocation.getCASOptions().EnableCaching ||
+        Invocation.getCASOptions().ImportModuleFromCAS)
       ESML = ExplicitCASModuleLoader::create(
           *Context, getObjectStore(), getActionCache(), getDependencyTracker(),
           MLM, Invocation.getSearchPathOptions().ExplicitSwiftModuleMapPath,
@@ -807,18 +857,14 @@ bool CompilerInstance::setUpModuleLoaders() {
   }
 
   // Configure ModuleInterfaceChecker for the ASTContext.
-  auto CacheFromInvocation = getInvocation().getClangModuleCachePath();
   auto const &Clang = clangImporter->getClangInstance();
-  std::string ModuleCachePath = CacheFromInvocation.empty()
+  std::string ModuleCachePath = ModuleCachePathFromInvocation.empty()
                                     ? getModuleCachePathFromClang(Clang)
-                                    : CacheFromInvocation.str();
-  auto &FEOpts = Invocation.getFrontendOptions();
-  ModuleInterfaceLoaderOptions LoaderOpts(FEOpts);
+                                    : ModuleCachePathFromInvocation.str();
   Context->addModuleInterfaceChecker(
       std::make_unique<ModuleInterfaceCheckerImpl>(
           *Context, ModuleCachePath, FEOpts.PrebuiltModuleCachePath,
-          FEOpts.BackupModuleInterfaceDir, LoaderOpts,
-          RequireOSSAModules_t(Invocation.getSILOptions())));
+          FEOpts.BackupModuleInterfaceDir, LoaderOpts));
 
   // Install an explicit module loader if it was created earlier.
   if (ESML) {
@@ -858,17 +904,9 @@ bool CompilerInstance::setUpModuleLoaders() {
         LoaderOpts,
         /*buildModuleCacheDirIfAbsent*/ false, ClangModuleCachePath,
         FEOpts.PrebuiltModuleCachePath, FEOpts.BackupModuleInterfaceDir,
+        FEOpts.CacheReplayPrefixMap,
         FEOpts.SerializeModuleInterfaceDependencyHashes,
-        FEOpts.shouldTrackSystemDependencies(),
-        RequireOSSAModules_t(Invocation.getSILOptions()));
-    auto mainModuleName = Context->getIdentifier(FEOpts.ModuleName);
-    std::unique_ptr<PlaceholderSwiftModuleScanner> PSMS =
-        std::make_unique<PlaceholderSwiftModuleScanner>(
-            *Context, MLM, mainModuleName,
-            Context->SearchPathOpts.PlaceholderDependencyModuleMap, ASTDelegate,
-            getInvocation().getFrontendOptions().ExplicitModulesOutputPath,
-            getInvocation().getFrontendOptions().ExplicitSDKModulesOutputPath);
-    Context->addModuleLoader(std::move(PSMS));
+        FEOpts.shouldTrackSystemDependencies());
   }
 
   return false;
@@ -878,6 +916,7 @@ bool CompilerInstance::setUpPluginLoader() {
   /// FIXME: If Invocation has 'PluginRegistry', we can set it. But should we?
   auto loader = std::make_unique<PluginLoader>(
       *Context, getDependencyTracker(),
+      Invocation.getFrontendOptions().CacheReplayPrefixMap,
       Invocation.getFrontendOptions().DisableSandbox);
   Context->setPluginLoader(std::move(loader));
   return false;
@@ -929,10 +968,10 @@ std::string CompilerInstance::getBridgingHeaderPath() const {
 }
 
 bool CompilerInstance::setUpInputs() {
-  // There is no input file when building PCM using ClangIncludeTree.
+  // There is no input file when building PCM using Caching.
   if (Invocation.getFrontendOptions().RequestedAction ==
           FrontendOptions::ActionType::EmitPCM &&
-      Invocation.getClangImporterOptions().HasClangIncludeTreeRoot)
+      Invocation.getCASOptions().EnableCaching)
     return false;
 
   // Adds to InputSourceCodeBufferIDs, so may need to happen before the
@@ -1126,7 +1165,7 @@ bool CompilerInvocation::shouldImportCxx() const {
   if (getFrontendOptions().ModuleName == CXX_MODULE_NAME)
     return false;
   // Cxx cannot be imported when Library evolution is enabled
-  if (getFrontendOptions().EnableLibraryEvolution)
+  if (getLangOptions().hasFeature(Feature::LibraryEvolution))
     return false;
   // Implicit import of Cxx is disabled
   if (getLangOptions().DisableImplicitCxxModuleImport)
@@ -1409,13 +1448,17 @@ static void configureAvailabilityDomains(const ASTContext &ctx,
   llvm::SmallDenseMap<Identifier, const CustomAvailabilityDomain *> domainMap;
   auto createAndInsertDomain = [&](const std::string &name,
                                    CustomAvailabilityDomain::Kind kind) {
-    auto *domain = CustomAvailabilityDomain::get(name, mainModule, kind, ctx);
+    auto *domain = CustomAvailabilityDomain::get(name, kind, mainModule,
+                                                 nullptr, nullptr, ctx);
     bool inserted = domainMap.insert({domain->getName(), domain}).second;
     ASSERT(inserted); // Domains must be unique.
   };
 
   for (auto enabled : opts.AvailabilityDomains.EnabledDomains)
     createAndInsertDomain(enabled, CustomAvailabilityDomain::Kind::Enabled);
+  for (auto alwaysEnabled : opts.AvailabilityDomains.AlwaysEnabledDomains)
+    createAndInsertDomain(alwaysEnabled,
+                          CustomAvailabilityDomain::Kind::AlwaysEnabled);
   for (auto disabled : opts.AvailabilityDomains.DisabledDomains)
     createAndInsertDomain(disabled, CustomAvailabilityDomain::Kind::Disabled);
   for (auto dynamic : opts.AvailabilityDomains.DynamicDomains)
@@ -1456,7 +1499,7 @@ ModuleDecl *CompilerInstance::getMainModule() const {
       MainModule->setPublicModuleName(getASTContext().getIdentifier(
           Invocation.getFrontendOptions().PublicModuleName));
     }
-    if (Invocation.getFrontendOptions().EnableLibraryEvolution)
+    if (Invocation.getLangOptions().hasFeature(Feature::LibraryEvolution))
       MainModule->setResilienceStrategy(ResilienceStrategy::Resilient);
     if (Invocation.getLangOptions().isSwiftVersionAtLeast(6))
       MainModule->setIsConcurrencyChecked(true);
@@ -1472,8 +1515,9 @@ ModuleDecl *CompilerInstance::getMainModule() const {
       MainModule->setSerializePackageEnabled();
     if (Invocation.getLangOptions().hasFeature(Feature::StrictMemorySafety))
       MainModule->setStrictMemorySafety(true);
-    if (Invocation.getLangOptions().hasFeature(Feature::ExtensibleEnums))
-      MainModule->setSupportsExtensibleEnums(true);
+    if (Invocation.getLangOptions().hasFeature(Feature::Embedded) &&
+        Invocation.getLangOptions().hasFeature(Feature::DeferredCodeGen))
+      MainModule->setDeferredCodeGen(true);
 
     configureAvailabilityDomains(getASTContext(),
                                  Invocation.getFrontendOptions(), MainModule);
@@ -1516,30 +1560,12 @@ void CompilerInstance::setMainModule(ModuleDecl *newMod) {
 bool CompilerInstance::performParseAndResolveImportsOnly() {
   FrontendStatsTracer tracer(getStatsReporter(), "parse-and-resolve-imports");
 
-  auto *mainModule = getMainModule();
-
-  // Load access notes.
-  if (!Invocation.getFrontendOptions().AccessNotesPath.empty()) {
-    auto accessNotesPath = Invocation.getFrontendOptions().AccessNotesPath;
-
-    auto bufferOrError =
-        swift::vfs::getFileOrSTDIN(getFileSystem(), accessNotesPath);
-    if (bufferOrError) {
-      int sourceID =
-          SourceMgr.addNewSourceBuffer(std::move(bufferOrError.get()));
-      auto buffer =
-          SourceMgr.getLLVMSourceMgr().getMemoryBuffer(sourceID);
-
-      if (auto accessNotesFile = AccessNotesFile::load(*Context, buffer))
-        mainModule->getAccessNotes() = *accessNotesFile;
-    }
-    else {
-      Diagnostics.diagnose(SourceLoc(), diag::access_notes_file_io_error,
-                           accessNotesPath, bufferOrError.getError().message());
-    }
-  }
+  // NOTE: Do not add new logic to this function, use the request evaluator to
+  // lazily evaluate instead. Once the below computations are requestified we
+  // ought to be able to remove this function.
 
   // Resolve imports for all the source files in the module.
+  auto *mainModule = getMainModule();
   performImportResolution(mainModule);
 
   bindExtensions(*mainModule);
@@ -1837,6 +1863,23 @@ bool CompilerInstance::performSILProcessing(SILModule *silModule) {
   return false;
 }
 
+void CompilerInstance::emitEndOfPipelineDebuggingOutput() {
+  assert(hasASTContext());
+  auto &ctx = getASTContext();
+  const auto &Invocation = getInvocation();
+  const auto &opts = Invocation.getFrontendOptions().CompilerDebuggingOpts;
+
+  if (opts.PrintClangStats && ctx.getClangModuleLoader())
+    ctx.getClangModuleLoader()->printStatistics();
+
+  if (opts.DumpAvailabilityScopes)
+    getPrimaryOrMainSourceFile().getAvailabilityScope()->dump(llvm::errs(),
+                                                              ctx.SourceMgr);
+
+  if (opts.DumpClangLookupTables && ctx.getClangModuleLoader())
+    ctx.getClangModuleLoader()->dumpSwiftLookupTables();
+}
+
 bool CompilerInstance::isCancellationRequested() const {
   auto flag = getASTContext().CancellationFlag;
   return flag && flag->load(std::memory_order_relaxed);
diff --git a/lib/Frontend/FrontendInputsAndOutputs.cpp b/lib/Frontend/FrontendInputsAndOutputs.cpp
index 8750e0edb34ff..228275d8f38b7 100644
--- a/lib/Frontend/FrontendInputsAndOutputs.cpp
+++ b/lib/Frontend/FrontendInputsAndOutputs.cpp
@@ -380,13 +380,23 @@ void FrontendInputsAndOutputs::setMainAndSupplementaryOutputs(
     }
     return;
   }
-  assert(supplementaryOutputs.size() == 1 &&
-         "WMO only ever produces one set of supplementary outputs");
+
+  assert(supplementaryOutputs.size() == 1 ||
+         supplementaryOutputs.size() == AllInputs.size() &&
+             "WMO produces wrong number of sets of supplementary outputs");
   if (outputFiles.size() == 1) {
-    AllInputs.front().setPrimarySpecificPaths(PrimarySpecificPaths(
-        outputFiles.front(), outputFilesForIndexUnits.front(),
-        firstInputProducingOutput().getFileName(),
-        supplementaryOutputs.front()));
+    for (auto i : indices(AllInputs)) {
+      if (i == 0)
+        AllInputs[i].setPrimarySpecificPaths(PrimarySpecificPaths(
+            outputFiles.front(), outputFilesForIndexUnits.front(),
+            firstInputProducingOutput().getFileName(),
+            supplementaryOutputs.front()));
+      else
+        AllInputs[i].setPrimarySpecificPaths(PrimarySpecificPaths(
+            "", "", "",
+            supplementaryOutputs.size() == 1 ? SupplementaryOutputPaths()
+                                             : supplementaryOutputs[i]));
+    }
     return;
   }
   assert(outputFiles.size() == AllInputs.size() &&
@@ -394,7 +404,8 @@ void FrontendInputsAndOutputs::setMainAndSupplementaryOutputs(
   for (auto i : indices(AllInputs))
     AllInputs[i].setPrimarySpecificPaths(PrimarySpecificPaths(
         outputFiles[i], outputFilesForIndexUnits[i], outputFiles[i],
-        i == 0 ? supplementaryOutputs.front() : SupplementaryOutputPaths()));
+        supplementaryOutputs.size() == 1 && i != 0 ? SupplementaryOutputPaths()
+                                                   : supplementaryOutputs[i]));
 }
 
 std::vector<std::string> FrontendInputsAndOutputs::copyOutputFilenames() const {
@@ -488,6 +499,14 @@ FrontendInputsAndOutputs::getPrimarySpecificPathsForAtMostOnePrimary() const {
                      : emptyPaths;
 }
 
+const PrimarySpecificPaths &
+FrontendInputsAndOutputs::getPrimarySpecificPathsForRemaining(unsigned i) const {
+  static auto emptyPaths = PrimarySpecificPaths();
+  unsigned firstProducingIdx = getIndexOfFirstOutputProducingInput();
+  return (hasInputs()  && i > 0) ?
+    AllInputs[firstProducingIdx+i].getPrimarySpecificPaths() : emptyPaths;
+}
+
 const PrimarySpecificPaths &
 FrontendInputsAndOutputs::getPrimarySpecificPathsForPrimary(
     StringRef filename) const {
diff --git a/lib/Frontend/FrontendOptions.cpp b/lib/Frontend/FrontendOptions.cpp
index 908ac19fdefd5..3cf4b1ece3fee 100644
--- a/lib/Frontend/FrontendOptions.cpp
+++ b/lib/Frontend/FrontendOptions.cpp
@@ -41,7 +41,6 @@ bool FrontendOptions::needsProperModuleName(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpPCM:
   case ActionType::EmitPCH:
     return false;
@@ -58,7 +57,7 @@ bool FrontendOptions::needsProperModuleName(ActionType action) {
   case ActionType::Immediate:
   case ActionType::REPL:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::EmitAssembly:
   case ActionType::EmitIRGen:
@@ -82,7 +81,7 @@ bool FrontendOptions::shouldActionOnlyParse(ActionType action) {
   case ActionType::EmitImportedModules:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return true;
   default:
     return false;
@@ -103,7 +102,7 @@ bool FrontendOptions::doesActionRequireSwiftStandardLibrary(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::ResolveImports:
   case ActionType::Typecheck:
@@ -111,7 +110,6 @@ bool FrontendOptions::doesActionRequireSwiftStandardLibrary(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
   case ActionType::EmitLoweredSIL:
@@ -138,7 +136,7 @@ bool FrontendOptions::doesActionRequireInputs(ActionType action) {
   switch (action) {
   case ActionType::NoneAction:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::REPL:
   case ActionType::Parse:
@@ -157,7 +155,6 @@ bool FrontendOptions::doesActionRequireInputs(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
   case ActionType::EmitLoweredSIL:
@@ -181,7 +178,7 @@ bool FrontendOptions::doesActionPerformEndOfPipelineActions(ActionType action) {
   switch (action) {
   case ActionType::NoneAction:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
   case ActionType::EmitPCH:
   case ActionType::EmitPCM:
   case ActionType::DumpPCM:
@@ -200,7 +197,6 @@ bool FrontendOptions::doesActionPerformEndOfPipelineActions(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
   case ActionType::EmitLoweredSIL:
@@ -226,7 +222,7 @@ bool FrontendOptions::supportCompilationCaching(ActionType action) {
   switch (action) {
   case ActionType::NoneAction:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
   case ActionType::DumpPCM:
   case ActionType::REPL:
   case ActionType::Parse:
@@ -239,7 +235,6 @@ bool FrontendOptions::supportCompilationCaching(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::MergeModules:
   case ActionType::Immediate:
   case ActionType::DumpTypeInfo:
@@ -305,7 +300,6 @@ FrontendOptions::formatForPrincipalOutputFileForAction(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::DumpPCM:
   case ActionType::PrintVersion:
@@ -362,8 +356,8 @@ FrontendOptions::formatForPrincipalOutputFileForAction(ActionType action) {
 
   case ActionType::ScanDependencies:
     return TY_JSONDependencies;
-  case ActionType::PrintFeature:
-    return TY_JSONFeatures;
+  case ActionType::PrintArguments:
+    return TY_JSONArguments;
   }
   llvm_unreachable("unhandled action");
 }
@@ -378,7 +372,6 @@ bool FrontendOptions::canActionEmitDependencies(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -386,7 +379,7 @@ bool FrontendOptions::canActionEmitDependencies(ActionType action) {
   case ActionType::REPL:
   case ActionType::DumpPCM:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::ResolveImports:
   case ActionType::Typecheck:
@@ -422,7 +415,6 @@ bool FrontendOptions::canActionEmitReferenceDependencies(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -432,7 +424,7 @@ bool FrontendOptions::canActionEmitReferenceDependencies(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::Typecheck:
   case ActionType::MergeModules:
@@ -467,7 +459,6 @@ bool FrontendOptions::canActionEmitModuleSummary(ActionType action) {
   case ActionType::EmitImportedModules:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIBGen:
@@ -482,7 +473,7 @@ bool FrontendOptions::canActionEmitModuleSummary(ActionType action) {
   case ActionType::MergeModules:
   case ActionType::EmitModuleOnly:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::EmitSIL:
   case ActionType::EmitLoweredSIL:
@@ -509,7 +500,6 @@ bool FrontendOptions::canActionEmitClangHeader(ActionType action) {
   case ActionType::PrintASTDecl:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -519,7 +509,7 @@ bool FrontendOptions::canActionEmitClangHeader(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::Typecheck:
   case ActionType::MergeModules:
@@ -550,7 +540,6 @@ bool FrontendOptions::canActionEmitLoadedModuleTrace(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -560,7 +549,7 @@ bool FrontendOptions::canActionEmitLoadedModuleTrace(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::ResolveImports:
   case ActionType::Typecheck:
@@ -600,7 +589,6 @@ bool FrontendOptions::canActionEmitModuleSemanticInfo(ActionType action) {
   case ActionType::PrintASTDecl:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::TypecheckModuleFromInterface:
@@ -610,7 +598,7 @@ bool FrontendOptions::canActionEmitModuleSemanticInfo(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
   case ActionType::EmitSIL:
   case ActionType::EmitLoweredSIL:
   case ActionType::EmitSIBGen:
@@ -643,7 +631,6 @@ bool FrontendOptions::canActionEmitConstValues(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -653,7 +640,7 @@ bool FrontendOptions::canActionEmitConstValues(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::Typecheck:
   case ActionType::MergeModules:
@@ -687,7 +674,6 @@ bool FrontendOptions::canActionEmitModule(ActionType action) {
   case ActionType::PrintASTDecl:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::CompileModuleFromInterface:
@@ -698,7 +684,7 @@ bool FrontendOptions::canActionEmitModule(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::MergeModules:
   case ActionType::EmitModuleOnly:
@@ -733,7 +719,6 @@ bool FrontendOptions::canActionEmitInterface(ActionType action) {
   case ActionType::EmitImportedModules:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIBGen:
@@ -744,7 +729,7 @@ bool FrontendOptions::canActionEmitInterface(ActionType action) {
   case ActionType::EmitPCM:
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::ResolveImports:
   case ActionType::Typecheck:
@@ -776,7 +761,6 @@ bool FrontendOptions::canActionEmitAPIDescriptor(ActionType action) {
   case ActionType::EmitImportedModules:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIBGen:
@@ -787,7 +771,7 @@ bool FrontendOptions::canActionEmitAPIDescriptor(ActionType action) {
   case ActionType::EmitPCM:
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::ResolveImports:
   case ActionType::Typecheck:
@@ -818,7 +802,6 @@ bool FrontendOptions::doesActionProduceOutput(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitPCH:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
@@ -838,7 +821,7 @@ bool FrontendOptions::doesActionProduceOutput(ActionType action) {
   case ActionType::EmitPCM:
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return true;
 
   case ActionType::TypecheckModuleFromInterface:
@@ -877,7 +860,6 @@ bool FrontendOptions::doesActionProduceTextualOutput(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitImportedModules:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
@@ -889,7 +871,7 @@ bool FrontendOptions::doesActionProduceTextualOutput(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return true;
   }
   llvm_unreachable("unhandled action");
@@ -907,7 +889,6 @@ bool FrontendOptions::doesActionGenerateSIL(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitImportedModules:
   case ActionType::EmitPCH:
   case ActionType::CompileModuleFromInterface:
@@ -916,7 +897,7 @@ bool FrontendOptions::doesActionGenerateSIL(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::EmitSILGen:
   case ActionType::EmitSIBGen:
@@ -948,7 +929,6 @@ bool FrontendOptions::doesActionGenerateIR(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -967,7 +947,7 @@ bool FrontendOptions::doesActionGenerateIR(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
     return false;
   case ActionType::Immediate:
   case ActionType::REPL:
@@ -994,7 +974,6 @@ bool FrontendOptions::doesActionBuildModuleFromInterface(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::Typecheck:
   case ActionType::ResolveImports:
@@ -1011,7 +990,7 @@ bool FrontendOptions::doesActionBuildModuleFromInterface(ActionType action) {
   case ActionType::DumpPCM:
   case ActionType::ScanDependencies:
   case ActionType::PrintVersion:
-  case ActionType::PrintFeature:
+  case ActionType::PrintArguments:
   case ActionType::Immediate:
   case ActionType::REPL:
   case ActionType::EmitIRGen:
diff --git a/lib/Frontend/MakeStyleDependencies.cpp b/lib/Frontend/MakeStyleDependencies.cpp
index b4d2b88eeae5d..c28270a360c00 100644
--- a/lib/Frontend/MakeStyleDependencies.cpp
+++ b/lib/Frontend/MakeStyleDependencies.cpp
@@ -95,12 +95,12 @@ reversePathSortedFilenames(const Container &elts) {
 static void emitMakeDependenciesFile(std::vector<std::string> &dependencies,
                                      const FrontendOptions &opts,
                                      const InputFile &input,
-                                     const std::vector<std::string> &prefixMap,
+                                     const std::vector<std::pair<std::string, std::string>> &prefixMap,
                                      llvm::raw_ostream &os) {
   // Prefix map all the path if needed.
   if (!prefixMap.empty()) {
     SmallVector<llvm::MappedPrefix, 4> prefixes;
-    llvm::MappedPrefix::transformJoinedIfValid(prefixMap, prefixes);
+    llvm::MappedPrefix::transformPairs(prefixMap, prefixes);
     llvm::PrefixMapper mapper;
     mapper.addRange(prefixes);
     mapper.sort();
@@ -221,6 +221,7 @@ bool swift::emitMakeDependenciesIfNeeded(CompilerInstance &instance,
     if (auto err = CASBackend.storeMakeDependenciesFile(dependenciesFilePath,
                                                         buffer)) {
       instance.getDiags().diagnose(SourceLoc(), diag::error_cas,
+                                   "storing make-style dependency file",
                                    toString(std::move(err)));
       return true;
     }
diff --git a/lib/Frontend/ModuleInterfaceBuilder.cpp b/lib/Frontend/ModuleInterfaceBuilder.cpp
index ac50e5e7bfdfe..c44c5c1dab138 100644
--- a/lib/Frontend/ModuleInterfaceBuilder.cpp
+++ b/lib/Frontend/ModuleInterfaceBuilder.cpp
@@ -203,6 +203,7 @@ std::error_code ExplicitModuleInterfaceBuilder::buildSwiftModuleFromInterface(
     ArrayRef<std::string> CompiledCandidates,
     StringRef CompilerVersion) {
   auto Invocation = Instance.getInvocation();
+
   // Try building forwarding module first. If succeed, return.
   if (Instance.getASTContext()
           .getModuleInterfaceChecker()
@@ -254,6 +255,9 @@ std::error_code ExplicitModuleInterfaceBuilder::buildSwiftModuleFromInterface(
                  builtByCompiler);
       }
     }
+
+    // If requested, dump debugging output before exiting.
+    Instance.emitEndOfPipelineDebuggingOutput();
   };
 
   Instance.performSema();
@@ -306,7 +310,6 @@ std::error_code ExplicitModuleInterfaceBuilder::buildSwiftModuleFromInterface(
       return std::make_error_code(std::errc::not_supported);
     SerializationOpts.Dependencies = Deps;
   }
-  SerializationOpts.IsOSSA = SILOpts.EnableOSSAModules;
 
   SILMod->setSerializeSILAction([&]() {
     // We don't want to serialize module docs in the cache -- they
diff --git a/lib/Frontend/ModuleInterfaceLoader.cpp b/lib/Frontend/ModuleInterfaceLoader.cpp
index 33d8d7ed084f6..a6dfdbe394a91 100644
--- a/lib/Frontend/ModuleInterfaceLoader.cpp
+++ b/lib/Frontend/ModuleInterfaceLoader.cpp
@@ -213,10 +213,8 @@ class DiscoveredModule {
 namespace path = llvm::sys::path;
 
 static bool serializedASTLooksValid(const llvm::MemoryBuffer &buf,
-                                    bool requiresOSSAModules,
                                     StringRef requiredSDK) {
   auto VI = serialization::validateSerializedAST(buf.getBuffer(),
-                                                 requiresOSSAModules,
                                                  requiredSDK);
   return VI.status == serialization::Status::Valid;
 }
@@ -408,14 +406,11 @@ StringRef getFullDependencyPath(const FileDependency &dep,
 class UpToDateModuleCheker {
   ASTContext &ctx;
   llvm::vfs::FileSystem &fs;
-  RequireOSSAModules_t requiresOSSAModules;
 
 public:
-  UpToDateModuleCheker(ASTContext &ctx,
-                       RequireOSSAModules_t requiresOSSAModules)
+  UpToDateModuleCheker(ASTContext &ctx)
      : ctx(ctx),
-       fs(*ctx.SourceMgr.getFileSystem()),
-       requiresOSSAModules(requiresOSSAModules) {}
+       fs(*ctx.SourceMgr.getFileSystem()) {}
 
   // Check if all the provided file dependencies are up-to-date compared to
   // what's currently on disk.
@@ -460,7 +455,7 @@ class UpToDateModuleCheker {
 
     LLVM_DEBUG(llvm::dbgs() << "Validating deps of " << path << "\n");
     auto validationInfo = serialization::validateSerializedAST(
-        buf.getBuffer(), requiresOSSAModules,
+        buf.getBuffer(),
         ctx.LangOpts.SDKName, /*ExtendedValidationInfo=*/nullptr, &allDeps);
 
     if (validationInfo.status != serialization::Status::Valid) {
@@ -551,25 +546,22 @@ class ModuleInterfaceLoaderImpl {
   DependencyTracker *const dependencyTracker;
   const ModuleLoadingMode loadMode;
   ModuleInterfaceLoaderOptions Opts;
-  RequireOSSAModules_t requiresOSSAModules;
 
   ModuleInterfaceLoaderImpl(
       ASTContext &ctx, StringRef modulePath, StringRef interfacePath,
       StringRef moduleName, StringRef cacheDir, StringRef prebuiltCacheDir,
       StringRef backupInterfaceDir,
       SourceLoc diagLoc, ModuleInterfaceLoaderOptions Opts,
-      RequireOSSAModules_t requiresOSSAModules,
       DependencyTracker *dependencyTracker = nullptr,
       ModuleLoadingMode loadMode = ModuleLoadingMode::PreferSerialized)
       : ctx(ctx), fs(*ctx.SourceMgr.getFileSystem()), diags(ctx.Diags),
-        upToDateChecker(ctx, requiresOSSAModules),
+        upToDateChecker(ctx),
         modulePath(modulePath), interfacePath(interfacePath),
         moduleName(moduleName),
         prebuiltCacheDir(prebuiltCacheDir),
         backupInterfaceDir(backupInterfaceDir),
         cacheDir(cacheDir), diagnosticLoc(diagLoc),
-        dependencyTracker(dependencyTracker), loadMode(loadMode), Opts(Opts),
-        requiresOSSAModules(requiresOSSAModules) {}
+        dependencyTracker(dependencyTracker), loadMode(loadMode), Opts(Opts) {}
 
   std::string getBackupPublicModuleInterfacePath() {
     return getBackupPublicModuleInterfacePath(ctx.SourceMgr, backupInterfaceDir,
@@ -622,7 +614,6 @@ class ModuleInterfaceLoaderImpl {
       return false;
 
     auto looksValid = serializedASTLooksValid(*modBuf.get(),
-                                              requiresOSSAModules,
                                               ctx.LangOpts.SDKName);
     if (!looksValid)
       return false;
@@ -932,18 +923,10 @@ class ModuleInterfaceLoaderImpl {
           return std::make_error_code(std::errc::not_supported);
         } else if (isInResourceDir(adjacentMod) &&
                    loadMode == ModuleLoadingMode::PreferSerialized &&
-                   !version::isCurrentCompilerTagged() &&
+                   version::getCurrentCompilerSerializationTag().empty() &&
                    rebuildInfo.getOrInsertCandidateModule(adjacentMod)
                            .serializationStatus !=
-                       serialization::Status::SDKMismatch &&
-                   // FIXME (meg-gupta): We need to support recompilation of
-                   // modules in the resource directory if the mismatch is due
-                   // to importing a non-ossa module to an ossa module. This is
-                   // needed during ossa bringup, once -enable-ossa-modules is
-                   // on by default, this can be deleted.
-                   rebuildInfo.getOrInsertCandidateModule(adjacentMod)
-                           .serializationStatus !=
-                       serialization::Status::NotInOSSA) {
+                       serialization::Status::SDKMismatch) {
           // Special-case here: If we're loading a .swiftmodule from the resource
           // dir adjacent to the compiler, defer to the serialized loader instead
           // of falling back. This is to support local development of Swift,
@@ -1129,9 +1112,8 @@ class ModuleInterfaceLoaderImpl {
         ctx.SourceMgr, &ctx.Diags, ctx.SearchPathOpts, ctx.LangOpts,
         ctx.ClangImporterOpts, ctx.CASOpts, Opts,
         /*buildModuleCacheDirIfAbsent*/ true, cacheDir, prebuiltCacheDir,
-        backupInterfaceDir,
-        /*serializeDependencyHashes*/ false, trackSystemDependencies,
-        requiresOSSAModules);
+        backupInterfaceDir, /*replayPrefixMap=*/{},
+        /*serializeDependencyHashes*/ false, trackSystemDependencies);
 
     // Compute the output path if we're loading or emitting a cached module.
     SwiftInterfaceModuleOutputPathResolution::ResultTy resolvedOutputPath;
@@ -1294,6 +1276,34 @@ bool ModuleInterfaceCheckerImpl::isCached(StringRef DepPath) {
   return !PrebuiltCacheDir.empty() && DepPath.starts_with(PrebuiltCacheDir);
 }
 
+static FrontendOptions::ActionType
+reqestedModuleLoaderActionForFrontendOpts(const FrontendOptions &Opts) {
+  switch (Opts.RequestedAction) {
+  case FrontendOptions::ActionType::TypecheckModuleFromInterface:
+    return FrontendOptions::ActionType::Typecheck;
+  case FrontendOptions::ActionType::ScanDependencies:
+    return Opts.RequestedAction;
+  default:
+    return FrontendOptions::ActionType::EmitModuleOnly;
+  }
+}
+
+ModuleInterfaceLoaderOptions::ModuleInterfaceLoaderOptions(
+    const FrontendOptions &Opts, bool inheritDebuggingOpts)
+    : requestedAction(reqestedModuleLoaderActionForFrontendOpts(Opts)),
+      remarkOnRebuildFromInterface(Opts.RemarkOnRebuildFromModuleInterface),
+      disableInterfaceLock(Opts.DisableInterfaceFileLock),
+      disableImplicitSwiftModule(Opts.DisableImplicitModules),
+      disableBuildingInterface(Opts.DisableBuildingInterface),
+      downgradeInterfaceVerificationError(
+          Opts.DowngradeInterfaceVerificationError),
+      strictImplicitModuleContext(Opts.StrictImplicitModuleContext),
+      mainExecutablePath(Opts.MainExecutablePath) {
+  if (inheritDebuggingOpts) {
+    compilerDebuggingOptions = Opts.CompilerDebuggingOpts;
+  }
+}
+
 bool ModuleInterfaceLoader::isCached(StringRef DepPath) {
   return InterfaceChecker.isCached(DepPath);
 }
@@ -1308,8 +1318,8 @@ std::error_code ModuleInterfaceLoader::findModuleFilesInDirectory(
     std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-    bool skipBuildingInterface, bool IsFramework,
-    bool isTestableImport) {
+    bool IsCanImportLookup, bool IsFramework,
+    bool IsTestableImport) {
 
   // If running in OnlySerialized mode, ModuleInterfaceLoader
   // should not have been constructed at all.
@@ -1333,11 +1343,9 @@ std::error_code ModuleInterfaceLoader::findModuleFilesInDirectory(
   if (ModuleInterfaceSourcePath)
     ModuleInterfaceSourcePath->assign(InPath->begin(), InPath->end());
 
-  // If we've been told to skip building interfaces, we are done here and do
-  // not need to have the module actually built. For example, if we are
-  // currently answering a `canImport` query, it is enough to have found
-  // the interface.
-  if (skipBuildingInterface) {
+  // If we are currently answering a `canImport` query, it is enough to have
+  // found the interface.
+  if (IsCanImportLookup) {
     if (ModuleInterfacePath)
       ModuleInterfacePath->assign(InPath->begin(), InPath->end());
     return std::error_code();
@@ -1349,7 +1357,6 @@ std::error_code ModuleInterfaceLoader::findModuleFilesInDirectory(
       Ctx, ModPath, *InPath, ModuleName, InterfaceChecker.CacheDir,
       InterfaceChecker.PrebuiltCacheDir, InterfaceChecker.BackupInterfaceDir,
       ModuleID.Loc, InterfaceChecker.Opts,
-      InterfaceChecker.RequiresOSSAModules,
       dependencyTracker,
       llvm::is_contained(PreferInterfaceForModules, ModuleName)
           ? ModuleLoadingMode::PreferInterface
@@ -1403,7 +1410,7 @@ ModuleInterfaceCheckerImpl::getCompiledModuleCandidatesForInterface(
 
   ModuleInterfaceLoaderImpl Impl(Ctx, modulePath, interfacePath, moduleName,
                                  CacheDir, PrebuiltCacheDir, BackupInterfaceDir,
-                                 SourceLoc(), Opts, RequiresOSSAModules,
+                                 SourceLoc(), Opts,
                                  nullptr, Ctx.SearchPathOpts.ModuleLoadMode);
   std::vector<std::string> results;
   std::string adjacentMod, prebuiltMod;
@@ -1443,7 +1450,6 @@ bool ModuleInterfaceCheckerImpl::tryEmitForwardingModule(
   ModuleInterfaceLoaderImpl Impl(Ctx, modulePath, interfacePath, moduleName,
                                  CacheDir, PrebuiltCacheDir,
                                  BackupInterfaceDir, SourceLoc(), Opts,
-                                 RequiresOSSAModules,
                                  nullptr,
                                  ModuleLoadingMode::PreferSerialized);
   SmallVector<FileDependency, 16> deps;
@@ -1473,16 +1479,17 @@ bool ModuleInterfaceLoader::buildSwiftModuleFromSwiftInterface(
     const ClangImporterOptions &ClangOpts, const CASOptions &CASOpts,
     StringRef CacheDir, StringRef PrebuiltCacheDir,
     StringRef BackupInterfaceDir, StringRef ModuleName, StringRef InPath,
-    StringRef OutPath, StringRef ABIOutputPath, bool SerializeDependencyHashes,
-    bool TrackSystemDependencies, ModuleInterfaceLoaderOptions LoaderOpts,
-    RequireOSSAModules_t RequireOSSAModules,
+    StringRef OutPath, StringRef ABIOutputPath,
+    ArrayRef<std::pair<std::string, std::string>> replayPrefixMap,
+    bool SerializeDependencyHashes, bool TrackSystemDependencies,
+    ModuleInterfaceLoaderOptions LoaderOpts,
     bool silenceInterfaceDiagnostics) {
   InterfaceSubContextDelegateImpl astDelegate(
-      SourceMgr, &Diags, SearchPathOpts, LangOpts, ClangOpts, CASOpts, LoaderOpts,
+      SourceMgr, &Diags, SearchPathOpts, LangOpts, ClangOpts, CASOpts,
+      LoaderOpts,
       /*CreateCacheDirIfAbsent*/ true, CacheDir, PrebuiltCacheDir,
-      BackupInterfaceDir,
-      SerializeDependencyHashes, TrackSystemDependencies,
-      RequireOSSAModules);
+      BackupInterfaceDir, replayPrefixMap, SerializeDependencyHashes,
+      TrackSystemDependencies);
   ImplicitModuleInterfaceBuilder builder(SourceMgr, &Diags, astDelegate, InPath,
                                          SearchPathOpts.getSDKPath(),
                                          SearchPathOpts.getSysRoot(),
@@ -1547,7 +1554,7 @@ static bool readSwiftInterfaceVersionAndArgs(
 
   if (extractCompilerFlagsFromInterface(interfacePath, SB, ArgSaver,
                                         interfaceInfo.Arguments,
-                                        preferredTarget)) {
+                                        preferredTarget, &Diags)) {
     InterfaceSubContextDelegateImpl::diagnose(
         interfacePath, diagnosticLoc, SM, &Diags,
         diag::error_extracting_version_from_module_interface);
@@ -1608,8 +1615,7 @@ bool ModuleInterfaceLoader::buildExplicitSwiftModuleFromSwiftInterface(
     // up-to-date w.r.t. all of the dependencies it was built with. If so, early
     // exit.
     UpToDateModuleCheker checker(
-        Instance.getASTContext(),
-        RequireOSSAModules_t(Instance.getSILOptions()));
+        Instance.getASTContext());
     ModuleRebuildInfo rebuildInfo;
     SmallVector<FileDependency, 3> allDeps;
     std::unique_ptr<llvm::MemoryBuffer> moduleBuffer;
@@ -1657,7 +1663,7 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
     FrontendOptions::ActionType requestedAction,
     const SearchPathOptions &SearchPathOpts, const LangOptions &LangOpts,
     const ClangImporterOptions &clangImporterOpts, const CASOptions &casOpts,
-    bool suppressRemarks, RequireOSSAModules_t RequireOSSAModules) {
+    bool suppressNotes, bool suppressRemarks) {
   GenericArgs.push_back("-frontend");
   // Start with a genericSubInvocation that copies various state from our
   // invoking ASTContext.
@@ -1746,6 +1752,12 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
   genericSubInvocation.getDiagnosticOptions().SuppressWarnings = true;
   GenericArgs.push_back("-suppress-warnings");
 
+  // Inherit the parent invocation's setting on whether to suppress remarks
+  if (suppressNotes) {
+    genericSubInvocation.getDiagnosticOptions().SuppressNotes = true;
+    GenericArgs.push_back("-suppress-notes");
+  }
+
   // Inherit the parent invocation's setting on whether to suppress remarks
   if (suppressRemarks) {
     genericSubInvocation.getDiagnosticOptions().SuppressRemarks = true;
@@ -1764,12 +1776,6 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
   genericSubInvocation.getLangOptions().EnableObjCAttrRequiresFoundation = false;
   GenericArgs.push_back("-disable-objc-attr-requires-foundation-module");
 
-  // If we are supposed to use RequireOSSAModules, do so.
-  if (RequireOSSAModules) {
-    genericSubInvocation.getSILOptions().EnableOSSAModules = true;
-    GenericArgs.push_back("-enable-ossa-modules");
-  }
-
   if (LangOpts.DisableAvailabilityChecking) {
     genericSubInvocation.getLangOptions().DisableAvailabilityChecking = true;
     GenericArgs.push_back("-disable-availability-checking");
@@ -1785,11 +1791,6 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
       GenericArgs.push_back(ArgSaver.save(pair));
   });
 
-  if (LangOpts.hasFeature(Feature::LayoutPrespecialization)) {
-    genericSubInvocation.getLangOptions().enableFeature(
-        Feature::LayoutPrespecialization);
-  }
-
   genericSubInvocation.getClangImporterOptions().DirectClangCC1ModuleBuild =
       clangImporterOpts.DirectClangCC1ModuleBuild;
   genericSubInvocation.getClangImporterOptions().ClangImporterDirectCC1Scan =
@@ -1815,13 +1816,6 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
         casOpts.HasImmutableFileSystem;
     casOpts.enumerateCASConfigurationFlags(
         [&](StringRef Arg) { GenericArgs.push_back(ArgSaver.save(Arg)); });
-    // ClangIncludeTree is default on when caching is enabled.
-    genericSubInvocation.getClangImporterOptions().UseClangIncludeTree = true;
-  }
-
-  if (!clangImporterOpts.UseClangIncludeTree) {
-    genericSubInvocation.getClangImporterOptions().UseClangIncludeTree = false;
-    GenericArgs.push_back("-no-clang-include-tree");
   }
 }
 
@@ -1869,19 +1863,20 @@ InterfaceSubContextDelegateImpl::InterfaceSubContextDelegateImpl(
     ModuleInterfaceLoaderOptions LoaderOpts, bool buildModuleCacheDirIfAbsent,
     StringRef moduleCachePath, StringRef prebuiltCachePath,
     StringRef backupModuleInterfaceDir,
-    bool serializeDependencyHashes, bool trackSystemDependencies,
-    RequireOSSAModules_t requireOSSAModules)
+    ArrayRef<std::pair<std::string, std::string>> replayPrefixMap,
+    bool serializeDependencyHashes, bool trackSystemDependencies)
     : SM(SM), Diags(Diags), ArgSaver(Allocator) {
   genericSubInvocation.setMainExecutablePath(LoaderOpts.mainExecutablePath);
   inheritOptionsForBuildingInterface(LoaderOpts.requestedAction, searchPathOpts,
                                      langOpts, clangImporterOpts, casOpts,
-                                     Diags->getSuppressRemarks(),
-                                     requireOSSAModules);
+                                     Diags->getSuppressNotes(),
+                                     Diags->getSuppressRemarks());
   // Configure front-end input.
   auto &SubFEOpts = genericSubInvocation.getFrontendOptions();
   SubFEOpts.RequestedAction = LoaderOpts.requestedAction;
   SubFEOpts.StrictImplicitModuleContext =
       LoaderOpts.strictImplicitModuleContext;
+  SubFEOpts.CompilerDebuggingOpts = LoaderOpts.compilerDebuggingOptions;
   if (!moduleCachePath.empty()) {
     genericSubInvocation.setClangModuleCachePath(moduleCachePath);
   }
@@ -1916,6 +1911,7 @@ InterfaceSubContextDelegateImpl::InterfaceSubContextDelegateImpl(
     genericSubInvocation.getLangOptions().EnableAppExtensionRestrictions = true;
     GenericArgs.push_back("-application-extension");
   }
+  SubFEOpts.CacheReplayPrefixMap = replayPrefixMap;
 
   // Pass down -explicit-swift-module-map-file
   StringRef explicitSwiftModuleMap = searchPathOpts.ExplicitSwiftModuleMapPath;
@@ -1932,6 +1928,8 @@ InterfaceSubContextDelegateImpl::InterfaceSubContextDelegateImpl(
   // Load plugin libraries for macro expression as default arguments
   genericSubInvocation.getSearchPathOptions().PluginSearchOpts =
       searchPathOpts.PluginSearchOpts;
+  genericSubInvocation.getSearchPathOptions().ResolvedPluginVerification =
+      searchPathOpts.ResolvedPluginVerification;
 
   // Get module loading behavior options.
   genericSubInvocation.getSearchPathOptions().ScannerModuleValidation = searchPathOpts.ScannerModuleValidation;
@@ -2023,6 +2021,12 @@ InterfaceSubContextDelegateImpl::InterfaceSubContextDelegateImpl(
     GenericArgs.push_back(blocklist);
   }
 
+  // Inherit APINotes processing method
+  if (clangImporterOpts.LoadVersionIndependentAPINotes) {
+    GenericArgs.push_back("-version-independent-apinotes");
+    genericSubInvocation.getClangImporterOptions().LoadVersionIndependentAPINotes = true;
+  }  
+
   // Inherit the C++ interoperability mode.
   if (langOpts.EnableCXXInterop) {
     // Modelled after a reverse of validateCxxInteropCompatibilityMode
@@ -2054,6 +2058,24 @@ InterfaceSubContextDelegateImpl::InterfaceSubContextDelegateImpl(
       GenericArgs.push_back("-stdlib=libc++");
     }
   }
+
+  // Inherit Embedded Swift
+  if (langOpts.hasFeature(Feature::Embedded)) {
+    genericSubInvocation.getLangOptions().enableFeature(Feature::Embedded);
+    GenericArgs.push_back("-enable-experimental-feature");
+    GenericArgs.push_back("Embedded");
+  }
+
+  if (langOpts.DebuggerSupport) {
+    if (clangImporterOpts.DirectClangCC1ModuleBuild) {
+      subClangImporterOpts.ExtraArgs.push_back("-dwarf-ext-refs");
+      subClangImporterOpts.ExtraArgs.push_back("-fmodule-format=obj");
+        subClangImporterOpts.ExtraArgs.push_back("-debug-info-kind=standalone");
+    } else {
+      subClangImporterOpts.ExtraArgs.push_back("-gmodules");
+      subClangImporterOpts.ExtraArgs.push_back("-g");
+    }
+  }
 }
 
 /// Calculate an output filename in \p genericSubInvocation's cache path that
@@ -2130,19 +2152,6 @@ InterfaceSubContextDelegateImpl::runInSubCompilerInstance(StringRef moduleName,
     subInvocation.setSysRoot(sysroot.value());
   }
 
-  // FIXME: Hack for CoreGraphics.swiftmodule, which cannot be rebuilt because
-  // of a CF_OPTIONS bug (rdar://142762174).
-  if (moduleName == "CoreGraphics") {
-    subInvocation.getLangOptions().EnableCXXInterop = false;
-    subInvocation.getLangOptions().cxxInteropCompatVersion = {};
-    BuildArgs.erase(llvm::remove_if(BuildArgs,
-                                    [](StringRef arg) -> bool {
-                                      return arg.starts_with(
-                                          "-cxx-interoperability-mode=");
-                                    }),
-                    BuildArgs.end());
-  }
-
   // Calculate output path of the module.
   SwiftInterfaceModuleOutputPathResolution::ResultTy resolvedOutputPath;
   getCachedOutputPath(resolvedOutputPath, moduleName, interfacePath, sdkPath);
@@ -2236,13 +2245,14 @@ struct ExplicitSwiftModuleLoader::Implementation {
       return;
     }
 
-    auto hasError = parser.parseSwiftExplicitModuleMap(
+    auto error = parser.parseSwiftExplicitModuleMap(
         (*fileBufOrErr)->getMemBufferRef(), ExplicitModuleMap,
         ExplicitClangModuleMap, ModuleAliases);
-
-    if (hasError)
+    llvm::handleAllErrors(std::move(error), [this, &fileName](
+                                                const llvm::StringError &E) {
       Ctx.Diags.diagnose(SourceLoc(), diag::explicit_swift_module_map_corrupted,
-                         fileName);
+                         fileName, E.getMessage());
+    });
 
     // A single module map can define multiple modules; keep track of the ones
     // we've seen so that we don't generate duplicate flags.
@@ -2269,11 +2279,10 @@ struct ExplicitSwiftModuleLoader::Implementation {
   }
 
   void addCommandLineExplicitInputs(
-      const std::vector<std::pair<std::string, std::string>>
-          &commandLineExplicitInputs) {
+    const llvm::StringMap<std::string> &commandLineExplicitInputs) {
     for (const auto &moduleInput : commandLineExplicitInputs) {
-      ExplicitSwiftModuleInputInfo entry(moduleInput.second, {}, {}, {});
-      ExplicitModuleMap.try_emplace(moduleInput.first, std::move(entry));
+      ExplicitSwiftModuleInputInfo entry(moduleInput.getValue(), {}, {}, {});
+      ExplicitModuleMap.try_emplace(moduleInput.first(), std::move(entry));
     }
   }
 };
@@ -2295,7 +2304,7 @@ bool ExplicitSwiftModuleLoader::findModule(
     std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-    bool skipBuildingInterface, bool isTestableDependencyLookup,
+    bool IsCanImportLookup, bool isTestableDependencyLookup,
     bool &IsFramework, bool &IsSystemModule) {
   // Find a module with an actual, physical name on disk, in case
   // -module-alias is used (otherwise same).
@@ -2374,7 +2383,7 @@ std::error_code ExplicitSwiftModuleLoader::findModuleFilesInDirectory(
     std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-    bool skipBuildingInterface, bool IsFramework,
+    bool IsCanImportLookup, bool IsFramework,
     bool IsTestableDependencyLookup) {
   llvm_unreachable("Not supported in the Explicit Swift Module Loader.");
   return std::make_error_code(std::errc::not_supported);
@@ -2427,7 +2436,6 @@ bool ExplicitSwiftModuleLoader::canImportModule(
 
   auto metaData = serialization::validateSerializedAST(
       (*moduleBuf)->getBuffer(),
-      Ctx.SILOpts.EnableOSSAModules,
       Ctx.LangOpts.SDKName);
   versionInfo->setVersion(metaData.userModuleVersion,
                           ModuleVersionSourceKind::SwiftBinaryModule);
@@ -2445,7 +2453,7 @@ std::unique_ptr<ExplicitSwiftModuleLoader>
 ExplicitSwiftModuleLoader::create(ASTContext &ctx,
     DependencyTracker *tracker, ModuleLoadingMode loadMode,
     StringRef ExplicitSwiftModuleMap,
-    const std::vector<std::pair<std::string, std::string>> &ExplicitSwiftModuleInputs,
+    const llvm::StringMap<std::string> &ExplicitSwiftModuleInputs,
     bool IgnoreSwiftSourceInfoFile) {
   auto result = std::unique_ptr<ExplicitSwiftModuleLoader>(
     new ExplicitSwiftModuleLoader(ctx, tracker, loadMode,
@@ -2477,18 +2485,25 @@ struct ExplicitCASModuleLoader::Implementation {
                  llvm::cas::ActionCache &Cache)
       : Ctx(Ctx), CAS(CAS), Cache(Cache) {}
 
-  llvm::Expected<std::unique_ptr<llvm::MemoryBuffer>> loadBuffer(StringRef ID) {
+  std::unique_ptr<llvm::MemoryBuffer> loadBuffer(StringRef ID) {
     auto key = CAS.parseID(ID);
-    if (!key)
-      return key.takeError();
+    if (!key) {
+      Ctx.Diags.diagnose(SourceLoc(), diag::error_invalid_cas_id, ID,
+                         toString(key.takeError()));
+      return nullptr;
+    }
 
     auto ref = CAS.getReference(*key);
     if (!ref)
       return nullptr;
 
     auto loaded = CAS.getProxy(*ref);
-    if (!loaded)
-      return loaded.takeError();
+    if (!loaded) {
+      Ctx.Diags.diagnose(SourceLoc(), diag::error_cas,
+                         "loading module map from CAS",
+                         toString(loaded.takeError()));
+      return nullptr;
+    }
 
     return loaded->getMemoryBuffer();
   }
@@ -2501,11 +2516,6 @@ struct ExplicitCASModuleLoader::Implementation {
     llvm::StringMap<std::string> ModuleAliases;
     auto buf = loadBuffer(ID);
     if (!buf) {
-      Ctx.Diags.diagnose(SourceLoc(), diag::error_cas,
-                         toString(buf.takeError()));
-      return;
-    }
-    if (!*buf) {
       Ctx.Diags.diagnose(SourceLoc(), diag::explicit_swift_module_map_missing,
                          ID);
       return;
@@ -2513,13 +2523,14 @@ struct ExplicitCASModuleLoader::Implementation {
     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> fileBufOrErr =
         llvm::MemoryBuffer::getFile(ID);
 
-    auto hasError = parser.parseSwiftExplicitModuleMap(
-        (*buf)->getMemBufferRef(), ExplicitModuleMap, ExplicitClangModuleMap,
+    auto error = parser.parseSwiftExplicitModuleMap(
+        buf->getMemBufferRef(), ExplicitModuleMap, ExplicitClangModuleMap,
         ModuleAliases);
-
-    if (hasError)
+    llvm::handleAllErrors(std::move(error), [this,
+                                             &ID](const llvm::StringError &E) {
       Ctx.Diags.diagnose(SourceLoc(), diag::explicit_swift_module_map_corrupted,
-                         ID);
+                         ID, E.getMessage());
+    });
 
     std::set<std::string> moduleMapsSeen;
     std::vector<std::string> &extraClangArgs = Ctx.ClangImporterOpts.ExtraArgs;
@@ -2530,8 +2541,7 @@ struct ExplicitCASModuleLoader::Implementation {
     };
     for (auto &entry : ExplicitClangModuleMap) {
       const auto &moduleMapPath = entry.getValue().moduleMapPath;
-      if (!moduleMapPath.empty() &&
-          !Ctx.ClangImporterOpts.UseClangIncludeTree &&
+      if (!moduleMapPath.empty() && !Ctx.CASOpts.EnableCaching &&
           moduleMapsSeen.find(moduleMapPath) == moduleMapsSeen.end()) {
         moduleMapsSeen.insert(moduleMapPath);
         extraClangArgs.push_back(
@@ -2558,49 +2568,61 @@ struct ExplicitCASModuleLoader::Implementation {
   }
 
   void addCommandLineExplicitInputs(
-      const std::vector<std::pair<std::string, std::string>>
-          &commandLineExplicitInputs) {
+      const llvm::StringMap<std::string> &commandLineExplicitInputs) {
     for (const auto &moduleInput : commandLineExplicitInputs) {
-      ExplicitSwiftModuleInputInfo entry(moduleInput.second, {}, {}, {});
-      ExplicitModuleMap.try_emplace(moduleInput.first, std::move(entry));
+      ExplicitSwiftModuleInputInfo entry(moduleInput.getValue(), {}, {}, {});
+      ExplicitModuleMap.try_emplace(moduleInput.getKey(), std::move(entry));
     }
   }
 
-  llvm::Expected<std::unique_ptr<llvm::MemoryBuffer>>
-  loadFileBuffer(StringRef ID, StringRef Name) {
+  std::unique_ptr<llvm::MemoryBuffer>
+  loadFileBuffer(SourceLoc Loc, StringRef ID, StringRef Name) {
+    auto outputMissing = [&]() {
+      Ctx.Diags.diagnose(Loc, diag::error_opening_explicit_module_file, Name);
+      return nullptr;
+    };
+    auto casError = [&](StringRef Stage, llvm::Error Err) {
+      Ctx.Diags.diagnose(Loc, diag::error_cas, Stage, toString(std::move(Err)));
+      return nullptr;
+    };
     auto key = CAS.parseID(ID);
-    if (!key)
-      return key.takeError();
+    if (!key) {
+      Ctx.Diags.diagnose(Loc, diag::error_invalid_cas_id, ID,
+                         toString(key.takeError()));
+      return nullptr;
+    }
 
     auto moduleLookup = Cache.get(*key);
     if (!moduleLookup)
-      return moduleLookup.takeError();
+      return casError("looking up module output cache",
+                      moduleLookup.takeError());
+
     if (!*moduleLookup)
-      return nullptr;
+      return outputMissing();
 
     auto moduleRef = CAS.getReference(**moduleLookup);
     if (!moduleRef)
-      return nullptr;
+      return outputMissing();
 
     auto proxy = CAS.getProxy(*moduleRef);
     if (!proxy)
-      return proxy.takeError();
+      return casError("loading module build outputs", proxy.takeError());
 
     swift::cas::CompileJobResultSchema schema(CAS);
     if (!schema.isRootNode(*proxy))
-      return nullptr;
+      return outputMissing();
 
     auto result = schema.load(*moduleRef);
     if (!result)
-      return result.takeError();
+      return casError("loading module schema", result.takeError());
 
     auto output = result->getOutput(file_types::ID::TY_SwiftModuleFile);
     if (!output)
-      return nullptr;
+      return outputMissing();
 
     auto buf = CAS.getProxy(output->Object);
     if (!buf)
-      return buf.takeError();
+      return casError("loading dependency module", result.takeError());
 
     return buf->getMemoryBuffer(Name);
   }
@@ -2638,7 +2660,7 @@ bool ExplicitCASModuleLoader::findModule(
     std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-    bool skipBuildingInterface, bool isTestableDependencyLookup,
+    bool IsCanImportLookup, bool IsTestableDependencyLookup,
     bool &IsFramework, bool &IsSystemModule) {
   // Find a module with an actual, physical name on disk, in case
   // -module-alias is used (otherwise same).
@@ -2727,7 +2749,7 @@ std::error_code ExplicitCASModuleLoader::findModuleFilesInDirectory(
     std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-    bool skipBuildingInterface, bool IsFramework,
+    bool IsCanImportLookup, bool IsFramework,
     bool IsTestableDependencyLookup) {
   llvm_unreachable("Not supported in the Explicit Swift Module Loader.");
   return std::make_error_code(std::errc::not_supported);
@@ -2761,18 +2783,14 @@ bool ExplicitCASModuleLoader::canImportModule(
   std::string moduleCASID = it->second.moduleCacheKey
                                 ? *it->second.moduleCacheKey
                                 : it->second.modulePath;
-  auto moduleBuf = Impl.loadFileBuffer(moduleCASID, it->second.modulePath);
+  auto moduleBuf = Impl.loadFileBuffer(loc, moduleCASID, it->second.modulePath);
   if (!moduleBuf) {
-    Ctx.Diags.diagnose(loc, diag::error_cas, toString(moduleBuf.takeError()));
-    return false;
-  }
-  if (!*moduleBuf) {
     Ctx.Diags.diagnose(loc, diag::error_opening_explicit_module_file,
                        it->second.modulePath);
     return false;
   }
   auto metaData = serialization::validateSerializedAST(
-      (*moduleBuf)->getBuffer(), Ctx.SILOpts.EnableOSSAModules,
+      moduleBuf->getBuffer(),
       Ctx.LangOpts.SDKName);
   versionInfo->setVersion(metaData.userModuleVersion,
                           ModuleVersionSourceKind::SwiftBinaryModule);
@@ -2790,8 +2808,7 @@ std::unique_ptr<ExplicitCASModuleLoader> ExplicitCASModuleLoader::create(
     ASTContext &ctx, llvm::cas::ObjectStore &CAS, llvm::cas::ActionCache &cache,
     DependencyTracker *tracker, ModuleLoadingMode loadMode,
     StringRef ExplicitSwiftModuleMap,
-    const std::vector<std::pair<std::string, std::string>>
-        &ExplicitSwiftModuleInputs,
+    const llvm::StringMap<std::string> &ExplicitSwiftModuleInputs,
     bool IgnoreSwiftSourceInfoFile) {
   auto result =
       std::unique_ptr<ExplicitCASModuleLoader>(new ExplicitCASModuleLoader(
@@ -2886,11 +2903,12 @@ static std::string getContextHash(const CompilerInvocation &CI,
       // Application extension.
       unsigned(CI.getLangOptions().EnableAppExtensionRestrictions),
 
-      // Whether or not OSSA modules are enabled.
-      //
-      // If OSSA modules are enabled, we use a separate namespace of modules to
-      // ensure that we compile all swift interface files with the option set.
-      unsigned(CI.getSILOptions().EnableOSSAModules));
+      // Is the C++ interop enabled?
+      unsigned(CI.getLangOptions().EnableCXXInterop),
+
+      // Is Embedded Swift enabled?
+      unsigned(CI.getLangOptions().hasFeature(Feature::Embedded))
+  );
 
   return llvm::toString(llvm::APInt(64, H), 36, /*Signed=*/false);
 }
diff --git a/lib/Frontend/ModuleInterfaceSupport.cpp b/lib/Frontend/ModuleInterfaceSupport.cpp
index a70d91dc10199..8f7e3c0a0ff7e 100644
--- a/lib/Frontend/ModuleInterfaceSupport.cpp
+++ b/lib/Frontend/ModuleInterfaceSupport.cpp
@@ -271,6 +271,9 @@ static void printImports(raw_ostream &out,
       ModuleDecl::ImportFilterKind::Default,
       ModuleDecl::ImportFilterKind::ShadowedByCrossImportOverlay};
 
+  // FIXME: Scan over all imports in the module once to build up the attribute
+  // set for printed imports, instead of repeatedly doing linear scans for each
+  // kind of attribute.
   using ImportSet = llvm::SmallSet<ImportedModule, 8, ImportedModule::Order>;
   auto getImports = [M](ModuleDecl::ImportFilter filter) -> ImportSet {
     SmallVector<ImportedModule, 8> matchingImports;
@@ -355,6 +358,9 @@ static void printImports(raw_ostream &out,
         out << "@_spi(" << spiName << ") ";
     }
 
+    if (M->isModuleImportedPreconcurrency(importedModule))
+      out << "@preconcurrency ";
+
     if (Opts.printPackageInterface() &&
         !publicImportSet.count(import) &&
         packageOnlyImportSet.count(import))
@@ -688,10 +694,11 @@ class InheritedProtocolCollector {
     if (!printOptions.shouldPrint(nominal))
       return;
 
-    /// is this nominal specifically an 'actor'?
-    bool actorClass = false;
-    if (auto klass = dyn_cast<ClassDecl>(nominal))
-      actorClass = klass->isActor();
+    /// is this nominal specifically an 'actor' or 'distributed actor'?
+    bool anyActorClass = false;
+    if (auto klass = dyn_cast<ClassDecl>(nominal)) {
+      anyActorClass = klass->isAnyActor();
+    }
 
     SmallPtrSet<ProtocolDecl *, 16> handledProtocols;
 
@@ -704,8 +711,9 @@ class InheritedProtocolCollector {
 
     // Preserve the behavior of previous implementations which formatted of
     // empty extensions compactly with '{}' on the same line.
-    PrintOptions extensionPrintOptions = printOptions;
-    extensionPrintOptions.PrintEmptyMembersOnSameLine = true;
+    PrintOptions::OverrideScope extensionPrintingScope(printOptions);
+    OVERRIDE_PRINT_OPTION(extensionPrintingScope,
+                          PrintEmptyMembersOnSameLine, true);
 
     // Then walk the remaining ones, and see what we need to print.
     // FIXME: This will pick the availability attributes from the first sight
@@ -725,9 +733,11 @@ class InheritedProtocolCollector {
         // There is a special restriction on the Actor protocol in that
         // it is only valid to conform to Actor on an 'actor' decl,
         // not extensions of that 'actor'.
-        if (actorClass &&
-            inherited->isSpecificProtocol(KnownProtocolKind::Actor))
-          return TypeWalker::Action::SkipNode;
+        if (anyActorClass) {
+          if (inherited->isSpecificProtocol(KnownProtocolKind::Actor) ||
+              inherited->isSpecificProtocol(KnownProtocolKind::DistributedActor))
+            return TypeWalker::Action::SkipNode;
+        }
 
         // Do not synthesize an extension to print a conformance to an
         // invertible protocol, as their conformances are always re-inferred
@@ -744,7 +754,7 @@ class InheritedProtocolCollector {
             !M->isImportedImplementationOnly(inherited->getParentModule())) {
           auto protoAndAvailability = ProtocolAndAvailability(
               inherited, availability, isUnchecked, otherAttrs);
-          printSynthesizedExtension(out, extensionPrintOptions, M, nominal,
+          printSynthesizedExtension(out, printOptions, M, nominal,
                                     protoAndAvailability);
           return TypeWalker::Action::SkipNode;
         }
@@ -799,8 +809,7 @@ class InheritedProtocolCollector {
 
     ctx.evaluator.cacheOutput(ExtendedTypeRequest{extension},
                               nominal->getDeclaredType());
-    ctx.evaluator.cacheOutput(ExtendedNominalRequest{extension},
-                              const_cast<NominalTypeDecl *>(nominal));
+    extension->setExtendedNominal(const_cast<NominalTypeDecl *>(nominal));
 
     extension->print(printer, printOptions);
     printer << "\n";
diff --git a/lib/Frontend/PrintingDiagnosticConsumer.cpp b/lib/Frontend/PrintingDiagnosticConsumer.cpp
index 00806723d8c34..ee9d63f57524a 100644
--- a/lib/Frontend/PrintingDiagnosticConsumer.cpp
+++ b/lib/Frontend/PrintingDiagnosticConsumer.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -48,20 +48,20 @@ void PrintingDiagnosticConsumer::handleDiagnostic(SourceManager &SM,
 #if SWIFT_BUILD_SWIFT_SYNTAX
     // Use the swift-syntax formatter.
     auto bufferStack = DiagnosticBridge::getSourceBufferStack(SM, Info.Loc);
-    if (!bufferStack.empty()) {
-      if (Info.Kind != DiagnosticKind::Note)
-        DiagBridge.flush(Stream, /*includeTrailingBreak=*/true,
-                         /*forceColors=*/ForceColors);
+    if (Info.Kind != DiagnosticKind::Note || bufferStack.empty())
+      DiagBridge.flush(Stream, /*includeTrailingBreak=*/true,
+                       /*forceColors=*/ForceColors);
 
+    if (bufferStack.empty()) {
+      DiagBridge.emitDiagnosticWithoutLocation(Info, Stream, ForceColors);
+    } else {
       DiagBridge.enqueueDiagnostic(SM, Info, bufferStack.front());
-      break;
     }
-#endif
-
+    return;
+#else
     // Fall through when we don't have the new diagnostics renderer available.
-    // This also happens if the location of the diagnostic is invalid, because
-    // the new rendered cannot cope with that.
     LLVM_FALLTHROUGH;
+#endif
   }
 
   case DiagnosticOptions::FormattingStyle::LLVM:
@@ -165,14 +165,14 @@ SourceManager::GetMessage(SourceLoc Loc, llvm::SourceMgr::DiagKind Kind,
     auto CurMB = LLVMSourceMgr.getMemoryBuffer(findBufferContainingLoc(Loc));
 
     // Scan backward to find the start of the line.
-    const char *LineStart = Loc.Value.getPointer();
+    const char *LineStart = Loc.getPointer();
     const char *BufStart = CurMB->getBufferStart();
     while (LineStart != BufStart && LineStart[-1] != '\n' &&
            LineStart[-1] != '\r')
       --LineStart;
 
     // Get the end of the line.
-    const char *LineEnd = Loc.Value.getPointer();
+    const char *LineEnd = Loc.getPointer();
     const char *BufEnd = CurMB->getBufferEnd();
     while (LineEnd != BufEnd && LineEnd[0] != '\n' && LineEnd[0] != '\r')
       ++LineEnd;
@@ -203,10 +203,9 @@ SourceManager::GetMessage(SourceLoc Loc, llvm::SourceMgr::DiagKind Kind,
     LineAndCol = getPresumedLineAndColumnForLoc(Loc);
   }
 
-  return llvm::SMDiagnostic(LLVMSourceMgr, Loc.Value, BufferID,
-                            LineAndCol.first,
-                            LineAndCol.second-1, Kind, Msg.str(),
-                            LineStr, ColRanges, FixIts);
+  return llvm::SMDiagnostic(LLVMSourceMgr, Loc, BufferID, LineAndCol.first,
+                            LineAndCol.second - 1, Kind, Msg.str(), LineStr,
+                            ColRanges, FixIts);
 }
 
 // These must come after the declaration of AnnotatedSourceSnippet due to the
@@ -215,4 +214,6 @@ PrintingDiagnosticConsumer::PrintingDiagnosticConsumer(
     llvm::raw_ostream &stream)
     : Stream(stream) {}
 
-PrintingDiagnosticConsumer::~PrintingDiagnosticConsumer() {}
+PrintingDiagnosticConsumer::~PrintingDiagnosticConsumer() {
+  flush();
+}
diff --git a/lib/Frontend/Serialization.cpp b/lib/Frontend/Serialization.cpp
index 9470c884512bc..2236c9496a76d 100644
--- a/lib/Frontend/Serialization.cpp
+++ b/lib/Frontend/Serialization.cpp
@@ -26,7 +26,7 @@ using namespace swift;
 static ModuleDecl *getModule(ModuleOrSourceFile DC) {
   if (auto M = DC.dyn_cast<ModuleDecl *>())
     return M;
-  return DC.get<SourceFile *>()->getParentModule();
+  return cast<SourceFile *>(DC)->getParentModule();
 }
 
 static ASTContext &getContext(ModuleOrSourceFile DC) {
@@ -37,7 +37,7 @@ static void emitABIDescriptor(ModuleOrSourceFile DC,
                               const SerializationOptions &options) {
   using namespace swift::ide::api;
   if (!options.ABIDescriptorPath.empty()) {
-    if (DC.is<ModuleDecl *>()) {
+    if (isa<ModuleDecl *>(DC)) {
       auto &OutputBackend = getContext(DC).getOutputBackend();
       auto ABIDesFile = OutputBackend.createFile(options.ABIDescriptorPath);
       if (!ABIDesFile) {
@@ -54,7 +54,7 @@ static void emitABIDescriptor(ModuleOrSourceFile DC,
           return;
         }
       };
-      dumpModuleContent(DC.get<ModuleDecl *>(), *ABIDesFile, true,
+      dumpModuleContent(cast<ModuleDecl *>(DC), *ABIDesFile, true,
                         options.emptyABIDescriptor);
     }
   }
@@ -178,8 +178,8 @@ void swift::serialize(
   }
 
   if (!symbolGraphOptions.OutputDir.empty()) {
-    if (DC.is<ModuleDecl *>()) {
-      auto *M = DC.get<ModuleDecl *>();
+    if (isa<ModuleDecl *>(DC)) {
+      auto *M = cast<ModuleDecl *>(DC);
       FrontendStatsTracer tracer(getContext(DC).Stats,
                                  "Serialization, symbolgraph");
       symbolgraphgen::emitSymbolGraphForModule(M, symbolGraphOptions);
diff --git a/lib/Frontend/SerializedDiagnosticConsumer.cpp b/lib/Frontend/SerializedDiagnosticConsumer.cpp
index 3436805b6b65b..8818a778c4aa2 100644
--- a/lib/Frontend/SerializedDiagnosticConsumer.cpp
+++ b/lib/Frontend/SerializedDiagnosticConsumer.cpp
@@ -32,6 +32,7 @@
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Bitstream/BitstreamWriter.h"
+#include "llvm/Support/Mutex.h"
 
 using namespace swift;
 using namespace clang::serialized_diags;
@@ -217,6 +218,39 @@ class SerializedDiagnosticConsumer : public DiagnosticConsumer {
                              DiagnosticKind Kind,
                              StringRef Text, const DiagnosticInfo &Info);
 };
+
+/// A thread-safe version of SerializedDiagnosticConsumer which
+/// serializes access to all public API of the consumer.
+class ThreadSafeSerializedDiagnosticConsumer
+    : public SerializedDiagnosticConsumer {
+private:
+  llvm::sys::SmartMutex<true> DiagnosticConsumerStateLock;
+
+public:
+  ThreadSafeSerializedDiagnosticConsumer(StringRef serializedDiagnosticsPath,
+                                         bool emitMacroExpansionFiles)
+      : SerializedDiagnosticConsumer(serializedDiagnosticsPath,
+                                     emitMacroExpansionFiles) {}
+
+  bool finishProcessing() override {
+    llvm::sys::SmartScopedLock<true> Lock(DiagnosticConsumerStateLock);
+    // Note: this is only synchronized behind a log to ease debugging possible
+    // issues, this method must not be called more than once.
+    return SerializedDiagnosticConsumer::finishProcessing();
+  }
+
+  void informDriverOfIncompleteBatchModeCompilation() override {
+    llvm::sys::SmartScopedLock<true> Lock(DiagnosticConsumerStateLock);
+    SerializedDiagnosticConsumer::
+        informDriverOfIncompleteBatchModeCompilation();
+  }
+
+  void handleDiagnostic(SourceManager &SM,
+                        const DiagnosticInfo &Info) override {
+    llvm::sys::SmartScopedLock<true> Lock(DiagnosticConsumerStateLock);
+    SerializedDiagnosticConsumer::handleDiagnostic(SM, Info);
+  }
+};
 } // end anonymous namespace
 
 namespace swift {
@@ -227,6 +261,13 @@ namespace serialized_diagnostics {
     return std::make_unique<SerializedDiagnosticConsumer>(
         outputPath, emitMacroExpansionFiles);
   }
+
+  std::unique_ptr<DiagnosticConsumer> createThreadSafeConsumer(
+      StringRef outputPath, bool emitMacroExpansionFiles
+  ) {
+    return std::make_unique<ThreadSafeSerializedDiagnosticConsumer>(
+        outputPath, emitMacroExpansionFiles);
+  }
 } // namespace serialized_diagnostics
 } // namespace swift
 
diff --git a/lib/FrontendTool/CMakeLists.txt b/lib/FrontendTool/CMakeLists.txt
index e21505a2d6c57..e5001cde931af 100644
--- a/lib/FrontendTool/CMakeLists.txt
+++ b/lib/FrontendTool/CMakeLists.txt
@@ -27,4 +27,9 @@ target_link_libraries(swiftFrontendTool PRIVATE
     swiftSILOptimizer
     swiftThreading)
 
+if (SWIFT_BUILD_SWIFT_SYNTAX)
+  target_link_libraries(swiftFrontendTool PRIVATE
+    swiftASTGen)
+endif()
+
 set_swift_llvm_is_available(swiftFrontendTool)
diff --git a/lib/FrontendTool/FrontendTool.cpp b/lib/FrontendTool/FrontendTool.cpp
index cad14a63bd828..d91148fe0051f 100644
--- a/lib/FrontendTool/FrontendTool.cpp
+++ b/lib/FrontendTool/FrontendTool.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -23,6 +23,7 @@
 #include "swift/FrontendTool/FrontendTool.h"
 #include "Dependencies.h"
 #include "TBD.h"
+#include "swift/AST/ASTBridging.h"
 #include "swift/AST/ASTDumper.h"
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/AvailabilityScope.h"
@@ -38,6 +39,7 @@
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/TBDGenRequests.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/Basic/BasicBridging.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/Edit.h"
 #include "swift/Basic/FileSystem.h"
@@ -46,9 +48,11 @@
 #include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Basic/SourceManager.h"
 #include "swift/Basic/Statistic.h"
+#include "swift/Basic/SupportedFeatures.h"
 #include "swift/Basic/TargetInfo.h"
 #include "swift/Basic/UUID.h"
 #include "swift/Basic/Version.h"
+#include "swift/Bridging/ASTGen.h"
 #include "swift/ConstExtract/ConstExtract.h"
 #include "swift/DependencyScan/ScanDependencies.h"
 #include "swift/Frontend/CachedDiagnostics.h"
@@ -79,6 +83,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/CAS/BuiltinUnifiedCASDatabases.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IRReader/IRReader.h"
@@ -88,6 +93,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/JSON.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/VirtualOutputBackend.h"
 #include "llvm/Support/VirtualOutputBackends.h"
@@ -350,7 +356,8 @@ static bool buildModuleFromInterface(CompilerInstance &Instance) {
   assert(FEOpts.InputsAndOutputs.hasSingleInput());
   StringRef InputPath = FEOpts.InputsAndOutputs.getFilenameOfFirstInput();
   StringRef PrebuiltCachePath = FEOpts.PrebuiltModuleCachePath;
-  ModuleInterfaceLoaderOptions LoaderOpts(FEOpts);
+  ModuleInterfaceLoaderOptions LoaderOpts(FEOpts,
+                                          /*inheritDebuggingOpts=*/true);
   StringRef ABIPath = Instance.getPrimarySpecificPathsForAtMostOnePrimary()
                           .SupplementaryOutputs.ABIDescriptorOutputPath;
   bool IgnoreAdjacentModules = Instance.hasASTContext() &&
@@ -384,10 +391,9 @@ static bool buildModuleFromInterface(CompilerInstance &Instance) {
       Invocation.getClangImporterOptions(), Invocation.getCASOptions(),
       Invocation.getClangModuleCachePath(), PrebuiltCachePath,
       FEOpts.BackupModuleInterfaceDir, Invocation.getModuleName(), InputPath,
-      Invocation.getOutputFilename(), ABIPath,
+      Invocation.getOutputFilename(), ABIPath, FEOpts.CacheReplayPrefixMap,
       FEOpts.SerializeModuleInterfaceDependencyHashes,
       FEOpts.shouldTrackSystemDependencies(), LoaderOpts,
-      RequireOSSAModules_t(Invocation.getSILOptions()),
       IgnoreAdjacentModules);
 }
 
@@ -455,14 +461,6 @@ static bool dumpAndPrintScopeMap(const CompilerInstance &Instance,
   return Instance.getASTContext().hadError();
 }
 
-static SourceFile &
-getPrimaryOrMainSourceFile(const CompilerInstance &Instance) {
-  if (SourceFile *SF = Instance.getPrimarySourceFile()) {
-    return *SF;
-  }
-  return Instance.getMainModule()->getMainSourceFile();
-}
-
 /// Dumps the AST of all available primary source files. If corresponding output
 /// files were specified, use them; otherwise, dump the AST to stdout.
 static bool dumpAST(CompilerInstance &Instance,
@@ -509,7 +507,7 @@ static bool dumpAST(CompilerInstance &Instance,
   } else {
     // Some invocations don't have primary files. In that case, we default to
     // looking for the main file and dumping it to `stdout`.
-    auto &SF = getPrimaryOrMainSourceFile(Instance);
+    auto &SF = Instance.getPrimaryOrMainSourceFile();
     dumpAST(&SF, llvm::outs());
   }
   return Instance.getASTContext().hadError();
@@ -739,7 +737,8 @@ bool swift::performCompileStepsPostSema(CompilerInstance &Instance,
   const auto &Invocation = Instance.getInvocation();
   const FrontendOptions &opts = Invocation.getFrontendOptions();
 
-  auto getSILOptions = [&](const PrimarySpecificPaths &PSPs) -> SILOptions {
+  auto getSILOptions = [&](const PrimarySpecificPaths &PSPs,
+                           const std::vector<PrimarySpecificPaths> &auxPSPs) -> SILOptions {
     SILOptions SILOpts = Invocation.getSILOptions();
     if (SILOpts.OptRecordFile.empty()) {
       // Check if the record file path was passed via supplemental outputs.
@@ -748,6 +747,15 @@ bool swift::performCompileStepsPostSema(CompilerInstance &Instance,
           PSPs.SupplementaryOutputs.YAMLOptRecordPath :
           PSPs.SupplementaryOutputs.BitstreamOptRecordPath;
     }
+    if (!auxPSPs.empty()) {
+      assert(SILOpts.AuxOptRecordFiles.empty());
+      for (const auto &auxFile: auxPSPs) {
+        SILOpts.AuxOptRecordFiles.push_back(
+          SILOpts.OptRecordFormat == llvm::remarks::Format::YAML ?
+          auxFile.SupplementaryOutputs.YAMLOptRecordPath :
+          auxFile.SupplementaryOutputs.BitstreamOptRecordPath);
+      }
+    }
     return SILOpts;
   };
 
@@ -757,13 +765,24 @@ bool swift::performCompileStepsPostSema(CompilerInstance &Instance,
     // SILModule for the entire module.
     const PrimarySpecificPaths PSPs =
         Instance.getPrimarySpecificPathsForWholeModuleOptimizationMode();
-    SILOptions SILOpts = getSILOptions(PSPs);
+
+    std::vector<PrimarySpecificPaths> auxPSPs;
+    for (unsigned i = 1; i < opts.InputsAndOutputs.inputCount(); ++i) {
+      auto &auxPSP =
+        opts.InputsAndOutputs.getPrimarySpecificPathsForRemaining(i);
+      auxPSPs.push_back(auxPSP);
+    }
+
+    SILOptions SILOpts = getSILOptions(PSPs, auxPSPs);
     IRGenOptions irgenOpts = Invocation.getIRGenOptions();
     auto SM = performASTLowering(mod, Instance.getSILTypes(), SILOpts,
                                  &irgenOpts);
     return performCompileStepsPostSILGen(Instance, std::move(SM), mod, PSPs,
                                          ReturnValue, observer);
   }
+
+
+  std::vector<PrimarySpecificPaths> emptyAuxPSPs;
   // If there are primary source files, build a separate SILModule for
   // each source file, and run the remaining SILOpt-Serialize-IRGen-LLVM
   // once for each such input.
@@ -772,7 +791,7 @@ bool swift::performCompileStepsPostSema(CompilerInstance &Instance,
     for (auto *PrimaryFile : Instance.getPrimarySourceFiles()) {
       const PrimarySpecificPaths PSPs =
           Instance.getPrimarySpecificPathsForSourceFile(*PrimaryFile);
-      SILOptions SILOpts = getSILOptions(PSPs);
+      SILOptions SILOpts = getSILOptions(PSPs, emptyAuxPSPs);
     IRGenOptions irgenOpts = Invocation.getIRGenOptions();
       auto SM = performASTLowering(*PrimaryFile, Instance.getSILTypes(),
                                    SILOpts, &irgenOpts);
@@ -792,7 +811,7 @@ bool swift::performCompileStepsPostSema(CompilerInstance &Instance,
       if (opts.InputsAndOutputs.isInputPrimary(SASTF->getFilename())) {
         const PrimarySpecificPaths &PSPs =
             Instance.getPrimarySpecificPathsForPrimary(SASTF->getFilename());
-        SILOptions SILOpts = getSILOptions(PSPs);
+        SILOptions SILOpts = getSILOptions(PSPs, emptyAuxPSPs);
         auto SM = performASTLowering(*SASTF, Instance.getSILTypes(), SILOpts);
         result |= performCompileStepsPostSILGen(Instance, std::move(SM), mod,
                                                 PSPs, ReturnValue, observer);
@@ -1005,21 +1024,16 @@ static void performEndOfPipelineActions(CompilerInstance &Instance) {
   const auto &Invocation = Instance.getInvocation();
   const auto &opts = Invocation.getFrontendOptions();
 
-  // If we were asked to print Clang stats, do so.
-  if (opts.PrintClangStats && ctx.getClangModuleLoader())
-    ctx.getClangModuleLoader()->printStatistics();
-
   // Report AST stats if needed.
   if (auto *stats = ctx.Stats)
     countASTStats(*stats, Instance);
 
-  if (opts.DumpClangLookupTables && ctx.getClangModuleLoader())
-    ctx.getClangModuleLoader()->dumpSwiftLookupTables();
-
   // Report mangling stats if there was no error.
   if (!ctx.hadError())
     Mangle::printManglingStats();
 
+  Instance.emitEndOfPipelineDebuggingOutput();
+
   // Make sure we didn't load a module during a parse-only invocation, unless
   // it's -emit-imported-modules, which can load modules.
   auto action = opts.RequestedAction;
@@ -1130,7 +1144,7 @@ static void printSingleFrontendOpt(llvm::opt::OptTable &table, options::ID id,
   }
 }
 
-static bool printSwiftFeature(CompilerInstance &instance) {
+static bool printSwiftArguments(CompilerInstance &instance) {
   ASTContext &context = instance.getASTContext();
   const CompilerInvocation &invocation = instance.getInvocation();
   const FrontendOptions &opts = invocation.getFrontendOptions();
@@ -1226,8 +1240,8 @@ static bool performAction(CompilerInstance &Instance,
     return Instance.getASTContext().hadError();
   case FrontendOptions::ActionType::PrintVersion:
     return printSwiftVersion(Instance.getInvocation());
-  case FrontendOptions::ActionType::PrintFeature:
-    return printSwiftFeature(Instance);
+  case FrontendOptions::ActionType::PrintArguments:
+    return printSwiftArguments(Instance);
   case FrontendOptions::ActionType::REPL:
     llvm::report_fatal_error("Compiler-internal integrated REPL has been "
                              "removed; use the LLDB-enhanced REPL instead.");
@@ -1258,32 +1272,27 @@ static bool performAction(CompilerInstance &Instance,
   case FrontendOptions::ActionType::PrintAST:
     return withSemanticAnalysis(
         Instance, observer, [](CompilerInstance &Instance) {
-          getPrimaryOrMainSourceFile(Instance).print(
+          Instance.getPrimaryOrMainSourceFile().print(
               llvm::outs(), PrintOptions::printEverything());
           return Instance.getASTContext().hadError();
         });
   case FrontendOptions::ActionType::PrintASTDecl:
     return withSemanticAnalysis(
         Instance, observer, [](CompilerInstance &Instance) {
-          getPrimaryOrMainSourceFile(Instance).print(
+          Instance.getPrimaryOrMainSourceFile().print(
               llvm::outs(), PrintOptions::printDeclarations());
           return Instance.getASTContext().hadError();
         });
   case FrontendOptions::ActionType::DumpScopeMaps:
     return withSemanticAnalysis(
-        Instance, observer, [](CompilerInstance &Instance) {
+        Instance, observer,
+        [](CompilerInstance &Instance) {
           return dumpAndPrintScopeMap(Instance,
-                                      getPrimaryOrMainSourceFile(Instance));
-        }, /*runDespiteErrors=*/true);
-  case FrontendOptions::ActionType::DumpAvailabilityScopes:
-    return withSemanticAnalysis(
-        Instance, observer, [](CompilerInstance &Instance) {
-          getPrimaryOrMainSourceFile(Instance).getAvailabilityScope()->dump(
-              llvm::errs(), Instance.getASTContext().SourceMgr);
-          return Instance.getASTContext().hadError();
-        }, /*runDespiteErrors=*/true);
+                                      Instance.getPrimaryOrMainSourceFile());
+        },
+        /*runDespiteErrors=*/true);
   case FrontendOptions::ActionType::DumpInterfaceHash:
-    getPrimaryOrMainSourceFile(Instance).dumpInterfaceHash(llvm::errs());
+    Instance.getPrimaryOrMainSourceFile().dumpInterfaceHash(llvm::errs());
     return Instance.getASTContext().hadError();
   case FrontendOptions::ActionType::EmitImportedModules:
     return emitImportedModules(Instance.getMainModule(), opts,
@@ -1373,6 +1382,322 @@ static bool tryReplayCompilerResults(CompilerInstance &Instance) {
   return replayed;
 }
 
+/// Generate reproducer.
+///
+/// Return false if reproducer generation has error.
+static bool generateReproducer(CompilerInstance &Instance,
+                               ArrayRef<const char *> Args) {
+  if (!Instance.supportCaching()) {
+    Instance.getDiags().diagnose(SourceLoc(),
+                                 diag::error_gen_reproducer_not_caching);
+    return true;
+  }
+
+  auto &upstream = Instance.getObjectStore();
+  auto &diags = Instance.getDiags();
+  auto &casOpts = Instance.getInvocation().getCASOptions();
+
+  // Create a temp directory for reproducer.
+  llvm::SmallString<256> reproDir(
+      Instance.getInvocation().getFrontendOptions().GenReproducerDir);
+  if (!reproDir.empty()) {
+    if (!llvm::sys::fs::is_directory(reproDir)) {
+      auto errCode = llvm::sys::fs::create_directory(reproDir);
+      if (errCode) {
+        diags.diagnose(SourceLoc(), diag::error_cannot_create_reproducer_dir,
+                       reproDir, errCode.message());
+        return true;
+      }
+    }
+  } else {
+    auto errCode =
+        llvm::sys::fs::createUniqueDirectory("swift-reproducer", reproDir);
+    if (errCode) {
+      Instance.getDiags().diagnose(SourceLoc(),
+                                   diag::error_cannot_create_reproducer_dir,
+                                   reproDir, errCode.message());
+      return true;
+    }
+  }
+
+  // Create a CAS for all the inputs.
+  llvm::SmallString<256> casPath(reproDir);
+  llvm::sys::path::append(casPath, "cas");
+  clang::CASOptions newCAS;
+  newCAS.CASPath = casPath.str();
+  newCAS.PluginPath = casOpts.CASOpts.PluginPath;
+  newCAS.PluginOptions = casOpts.CASOpts.PluginOptions;
+  auto db = newCAS.getOrCreateDatabases();
+  if (!db) {
+    diags.diagnose(SourceLoc(), diag::error_cas_initialization,
+                   toString(db.takeError()));
+    return false;
+  }
+
+  llvm::StringMap<const char *> idsToUpdate;
+  llvm::BumpPtrAllocator alloc;
+  llvm::StringSaver argSaver(alloc);
+  auto newArgs = Args.vec();
+  // Import all dependencies.
+  auto importID = [&](StringRef str) {
+    if (str.empty())
+      return true;
+
+    auto id = upstream.parseID(str);
+    if (!id) {
+      diags.diagnose(SourceLoc(), diag::error_invalid_cas_id, str,
+                     toString(id.takeError()));
+      return true;
+    }
+    auto ref = upstream.getReference(*id);
+    if (!ref) {
+      diags.diagnose(SourceLoc(), diag::error_load_input_from_cas, str);
+      return true;
+    }
+
+    auto imported = db->first->importObject(upstream, *ref);
+    if (!imported) {
+      diags.diagnose(SourceLoc(), diag::error_cas, "import input dependency",
+                     toString(imported.takeError()));
+      return true;
+    }
+
+    auto newID = db->first->getID(*imported).toString();
+    if (newID != str)
+      idsToUpdate[str] = argSaver.save(newID).data();
+
+    return false;
+  };
+
+  auto importKey = [&](StringRef key) -> std::optional<std::string> {
+    if (key.empty())
+      return std::nullopt;
+
+    auto id = upstream.parseID(key);
+    if (!id) {
+      diags.diagnose(SourceLoc(), diag::error_invalid_cas_id, key,
+                     toString(id.takeError()));
+      return std::nullopt;
+    }
+    auto ref = upstream.getReference(*id);
+    if (!ref) {
+      diags.diagnose(SourceLoc(), diag::error_load_input_from_cas, key);
+      return std::nullopt;
+    }
+    // Import the entire key.
+    auto imported = db->first->importObject(upstream, *ref);
+    if (!imported) {
+      diags.diagnose(SourceLoc(), diag::error_cas, "import input dependency",
+                     toString(imported.takeError()));
+      return std::nullopt;
+    }
+    auto importedProxy = db->first->getProxy(*imported);
+    if (!importedProxy) {
+      diags.diagnose(SourceLoc(), diag::error_cas, "load imported dependency",
+                     toString(importedProxy.takeError()));
+      return std::nullopt;
+    }
+    // If not a binary module, check command-line and import some of its inputs.
+    // The command-line entries are stored in the format specified in
+    // Frontend/CompileJobCacheKey.cpp, where each command-line entry is
+    // space-separated option and its argument (if applicable).
+    if (importedProxy->getNumReferences() > 0) {
+      if (auto err = iterateCommandLine(
+              upstream, *ref, [&](StringRef arg) -> llvm::Error {
+                if (arg.consume_front("-clang-include-tree-root ") ||
+                    arg.consume_front("-clang-include-tree-filelist "))
+                  importID(arg);
+                return llvm::Error::success();
+              })) {
+        diags.diagnose(SourceLoc(), diag::error_cas, "import dependency cmd",
+                       toString(std::move(err)));
+        return std::nullopt;
+      }
+    }
+    // Import the value.
+    auto result = Instance.getActionCache().get(*id);
+    if (!result) {
+      diags.diagnose(SourceLoc(), diag::error_cas, "lookup key dependency",
+                     toString(result.takeError()));
+      return std::nullopt;
+    }
+    // Missing value in the action cache, this will result in a failed lookup
+    // later in the compilation so the reproducer is going to skip this entry.
+    if (!*result)
+      return std::nullopt;
+
+    auto value = upstream.getReference(**result);
+    if (!value)
+      return std::nullopt;
+
+    auto newValue = db->first->importObject(upstream, *value);
+    if (!newValue) {
+      diags.diagnose(SourceLoc(), diag::error_cas, "import value dependency",
+                     toString(newValue.takeError()));
+      return std::nullopt;
+    }
+
+    if (auto err = db->second->put(db->first->getID(*imported),
+                                   db->first->getID(*newValue))) {
+      diags.diagnose(SourceLoc(), diag::error_cas,
+                     "associate key/value dependency",
+                     toString(std::move(err)));
+      return std::nullopt;
+    }
+
+    return db->first->getID(*imported).toString();
+  };
+
+  auto mapKey = [&](StringRef key) {
+    auto imported = importKey(key);
+    if (!imported)
+      return true;
+
+    if (*imported != key)
+      idsToUpdate[key] = argSaver.save(*imported).data();
+
+    return false;
+  };
+
+  importID(casOpts.ClangIncludeTree);
+  importID(casOpts.ClangIncludeTreeFileList);
+
+  mapKey(casOpts.InputFileKey);
+  mapKey(casOpts.BridgingHeaderPCHCacheKey);
+
+  // Import module dependencies.
+  // If building clang/swift modules, the module dependencies are passed on
+  // command-line.
+  for (auto &mod : Instance.getInvocation()
+                       .getSearchPathOptions()
+                       .ExplicitSwiftModuleInputs)
+    importKey(mod.second);
+
+  const auto &clangArgs =
+      Instance.getInvocation().getClangImporterOptions().ExtraArgs;
+  for (auto xcc = clangArgs.begin(); xcc != clangArgs.end(); ++xcc) {
+    if (*xcc == "-fmodule-file-cache-key") {
+      // The clang module key is passed via: -fmodule-file-cache-key <PATH>
+      // <KEY>.
+      if (++xcc == clangArgs.end())
+        continue;
+      if (++xcc == clangArgs.end())
+        continue;
+      importKey(*xcc);
+    }
+  }
+
+  // If building current module, the module dependencies are passed inside
+  // explicit module map json file.
+  auto &mapOpts = Instance.getInvocation()
+                      .getSearchPathOptions()
+                      .ExplicitSwiftModuleMapPath;
+  if (!mapOpts.empty()) {
+    auto mapID = upstream.parseID(mapOpts);
+    if (!mapID) {
+      diags.diagnose(SourceLoc(), diag::error_invalid_cas_id, mapOpts,
+                     toString(mapID.takeError()));
+      return true;
+    }
+    auto mapProxy = upstream.getProxy(*mapID);
+    if (!mapProxy) {
+      diags.diagnose(SourceLoc(), diag::error_cas, "load module map",
+                     toString(mapProxy.takeError()));
+      return true;
+    }
+    auto map = llvm::json::parse(mapProxy->getData());
+    if (!map) {
+      llvm::handleAllErrors(
+          map.takeError(), [&diags, &mapOpts](const llvm::json::ParseError &E) {
+            diags.diagnose(SourceLoc(),
+                           diag::explicit_swift_module_map_corrupted, mapOpts,
+                           E.message());
+          });
+      return true;
+    }
+    if (auto array = map->getAsArray()) {
+      for (auto &entry : *array) {
+        if (auto dep = entry.getAsObject()) {
+          for (auto &obj : *dep) {
+            if (obj.first == "moduleCacheKey" ||
+                obj.first == "clangModuleCacheKey") {
+              if (auto dep = obj.second.getAsString())
+                importKey(*dep);
+            }
+          }
+        }
+      }
+    }
+
+    // Import explicit module map.
+    auto newMapRef = db->first->storeFromString({}, mapProxy->getData());
+    if (!newMapRef) {
+      diags.diagnose(SourceLoc(), diag::error_cas, "store module map",
+                     toString(newMapRef.takeError()));
+      return true;
+    }
+    auto newMapArg = db->first->getID(*newMapRef).toString();
+    if (newMapArg != mapOpts)
+      idsToUpdate[mapOpts] = argSaver.save(newMapArg).data();
+  }
+
+  // Drop all the options that no longer applies.
+  auto dropArg = [&newArgs](StringRef arg, bool hasArg = true) {
+    auto found =
+        llvm::find_if(newArgs, [&](const char *a) { return arg == a; });
+    if (found != newArgs.end())
+      found = newArgs.erase(found);
+    if (hasArg && found != newArgs.end())
+      found = newArgs.erase(found);
+  };
+  dropArg("-cas-path");
+  dropArg("-cas-plugin-path");
+  dropArg("-cas-plugin-option");
+  dropArg("-gen-reproducer", false);
+  dropArg("-gen-reproducer-dir");
+
+  // Now upgrade the entire command-line.
+  for (auto &arg : newArgs) {
+    if (idsToUpdate.count(arg))
+      arg = idsToUpdate[arg];
+  }
+
+  // Add the configuration for the new CAS options. Note those options and only
+  // these options will need to be adjusted if the reproducer is copied into a
+  // different location.
+  newArgs.push_back("-cas-path");
+  newArgs.push_back(casPath.c_str());
+  if (!newCAS.PluginPath.empty()) {
+    newArgs.push_back("-cas-plugin-path");
+    newArgs.push_back(newCAS.PluginPath.c_str());
+    for (auto Opt : newCAS.PluginOptions) {
+      newArgs.push_back("-cas-plugin-option");
+      newArgs.push_back(
+          argSaver.save(llvm::Twine(Opt.first) + "=" + Opt.second).data());
+    }
+  }
+
+  // Write shell script.
+  llvm::SmallString<256> scriptPath(reproDir);
+  llvm::sys::path::append(scriptPath, "reproduce.sh");
+
+  std::error_code ec;
+  llvm::raw_fd_ostream scriptOS(scriptPath, ec, llvm::sys::fs::CD_CreateNew,
+                                llvm::sys::fs::FA_Write,
+                                llvm::sys::fs::OF_Text);
+  if (ec) {
+    diags.diagnose(SourceLoc(), diag::error_cannot_create_reproducer_dir,
+                   scriptPath, ec.message());
+    return true;
+  }
+
+  for (auto &arg : newArgs)
+    scriptOS << "\"" << arg << "\" ";
+
+  diags.diagnose(SourceLoc(), diag::note_reproducer, reproDir);
+  return false;
+}
+
 /// Performs the compile requested by the user.
 /// \param Instance Will be reset after performIRGeneration when the verifier
 ///                 mode is NoVerify and there were no errors.
@@ -1432,7 +1757,6 @@ static bool serializeSIB(SILModule *SM, const PrimarySpecificPaths &PSPs,
   serializationOpts.OutputPath = moduleOutputPath;
   serializationOpts.SerializeAllSIL = true;
   serializationOpts.IsSIB = true;
-  serializationOpts.IsOSSA = Context.SILOpts.EnableOSSAModules;
 
   symbolgraphgen::SymbolGraphOptions symbolGraphOptions;
 
@@ -1464,7 +1788,7 @@ generateIR(const IRGenOptions &IRGenOpts, const TBDGenOptions &TBDOpts,
                                SF->getPrivateDiscriminator().str(),
                                &HashGlobal);
   } else {
-    return performIRGeneration(MSF.get<ModuleDecl *>(), IRGenOpts, TBDOpts,
+    return performIRGeneration(cast<ModuleDecl *>(MSF), IRGenOpts, TBDOpts,
                                std::move(SM), OutputFilename, PSPs,
                                parallelOutputFilenames, &HashGlobal);
   }
@@ -1477,15 +1801,15 @@ static bool processCommandLineAndRunImmediately(CompilerInstance &Instance,
                                                 int &ReturnValue) {
   const auto &Invocation = Instance.getInvocation();
   const auto &opts = Invocation.getFrontendOptions();
-  assert(!MSF.is<SourceFile *>() && "-i doesn't work in -primary-file mode");
+  assert(!isa<SourceFile *>(MSF) && "-i doesn't work in -primary-file mode");
   const IRGenOptions &IRGenOpts = Invocation.getIRGenOptions();
   const ProcessCmdLine &CmdLine =
       ProcessCmdLine(opts.ImmediateArgv.begin(), opts.ImmediateArgv.end());
 
   PrettyStackTraceStringAction trace(
-      "running user code",
-      MSF.is<SourceFile *>() ? MSF.get<SourceFile *>()->getFilename()
-                     : MSF.get<ModuleDecl *>()->getModuleFilename());
+      "running user code", isa<SourceFile *>(MSF)
+                               ? cast<SourceFile *>(MSF)->getFilename()
+                               : cast<ModuleDecl *>(MSF)->getModuleFilename());
 
   ReturnValue =
       RunImmediately(Instance, CmdLine, IRGenOpts, Invocation.getSILOptions(),
@@ -1576,7 +1900,7 @@ static bool validateTBDIfNeeded(const CompilerInvocation &Invocation,
   if (auto *SF = MSF.dyn_cast<SourceFile *>()) {
     return validateTBD(SF, IRModule, Opts, diagnoseExtraSymbolsInTBD);
   } else {
-    return validateTBD(MSF.get<ModuleDecl *>(), IRModule, Opts,
+    return validateTBD(cast<ModuleDecl *>(MSF), IRModule, Opts,
                        diagnoseExtraSymbolsInTBD);
   }
 }
@@ -1713,10 +2037,9 @@ static bool performCompileStepsPostSILGen(CompilerInstance &Instance,
     // We may want to rely on a flag instead to differentiate them.
     const bool isEmitModuleSeparately =
         Action == FrontendOptions::ActionType::EmitModuleOnly &&
-        MSF.is<ModuleDecl *>() &&
-        Instance.getInvocation()
-            .getTypeCheckerOptions()
-            .SkipFunctionBodies == FunctionBodySkipping::NonInlinableWithoutTypes;
+        isa<ModuleDecl *>(MSF) &&
+        Instance.getInvocation().getTypeCheckerOptions().SkipFunctionBodies ==
+            FunctionBodySkipping::NonInlinableWithoutTypes;
     const bool canEmitIncrementalInfoIntoModule =
         !serializationOpts.DisableCrossModuleIncrementalInfo &&
         (Action == FrontendOptions::ActionType::MergeModules ||
@@ -1728,7 +2051,7 @@ static bool performCompileStepsPostSILGen(CompilerInstance &Instance,
               .EmitFineGrainedDependencySourcefileDotFiles;
 
       using SourceFileDepGraph = fine_grained_dependencies::SourceFileDepGraph;
-      auto *Mod = MSF.get<ModuleDecl *>();
+      auto *Mod = cast<ModuleDecl *>(MSF);
       fine_grained_dependencies::withReferenceDependencies(
           Mod, *Instance.getDependencyTracker(),
           Instance.getOutputBackend(), Mod->getModuleFilename(),
@@ -1883,6 +2206,7 @@ static void emitIndexDataForSourceFile(SourceFile *PrimarySourceFile,
                                  opts.IndexSystemModules,
                                  opts.IndexIgnoreStdlib,
                                  opts.IndexIncludeLocals,
+                                 opts.IndexStoreCompress,
                                  isDebugCompilation,
                                  opts.DisableImplicitModules,
                                  Invocation.getTargetTriple(),
@@ -1902,6 +2226,7 @@ static void emitIndexDataForSourceFile(SourceFile *PrimarySourceFile,
                                  opts.IndexSystemModules,
                                  opts.IndexIgnoreStdlib,
                                  opts.IndexIncludeLocals,
+                                 opts.IndexStoreCompress,
                                  isDebugCompilation,
                                  opts.DisableImplicitModules,
                                  Invocation.getTargetTriple(),
@@ -1932,11 +2257,18 @@ class PrettyStackTraceFrontend : public llvm::PrettyStackTraceEntry {
   };
 };
 
+#if SWIFT_BUILD_SWIFT_SYNTAX
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
+extern "C" BridgedStringRef
+swift_ASTGen_printStaticBuildConfiguration(BridgedLangOptions cLangOpts);
+#pragma clang diagnostic pop
+#endif
+
 int swift::performFrontend(ArrayRef<const char *> Args,
                            const char *Argv0, void *MainAddr,
                            FrontendObserver *observer) {
   INITIALIZE_LLVM();
-  llvm::setBugReportMsg(SWIFT_CRASH_BUG_REPORT_MESSAGE "\n");
   llvm::EnablePrettyStackTraceOnSigInfoForThisThread();
 
   std::unique_ptr<CompilerInstance> Instance =
@@ -2063,6 +2395,21 @@ int swift::performFrontend(ArrayRef<const char *> Args,
     return finishDiagProcessing(0, /*verifierEnabled*/ false);
   }
 
+  if (Invocation.getFrontendOptions().PrintBuildConfig) {
+#if SWIFT_BUILD_SWIFT_SYNTAX
+    auto resultText =
+        swift_ASTGen_printStaticBuildConfiguration(Invocation.getLangOptions());
+    llvm::outs() << resultText.unbridged();
+    swift_ASTGen_freeBridgedString(resultText);
+#endif
+    return finishDiagProcessing(0, /*verifierEnabled*/ false);
+  }
+
+  if (Invocation.getFrontendOptions().PrintSupportedFeatures) {
+    swift::features::printSupportedFeatures(llvm::outs());
+    return finishDiagProcessing(0, /*verifierEnabled*/ false);
+  }
+
   if (Invocation.getFrontendOptions().RequestedAction ==
       FrontendOptions::ActionType::NoneAction) {
     Instance->getDiags().diagnose(SourceLoc(),
@@ -2092,6 +2439,12 @@ int swift::performFrontend(ArrayRef<const char *> Args,
     observer->configuredCompiler(*Instance);
   }
 
+  if (Invocation.getFrontendOptions().GenReproducer) {
+    int ReturnCode = generateReproducer(*Instance, Args) ? 1 : 0;
+    DH.endMessage(ReturnCode);
+    return finishDiagProcessing(ReturnCode, /*verifierEnabled*/ false);
+  }
+
   if (verifierEnabled) {
     // Suppress printed diagnostic output during the compile if the verifier is
     // enabled.
diff --git a/lib/FrontendTool/LoadedModuleTrace.cpp b/lib/FrontendTool/LoadedModuleTrace.cpp
index 6e58e15fb7df1..0c7600d516c13 100644
--- a/lib/FrontendTool/LoadedModuleTrace.cpp
+++ b/lib/FrontendTool/LoadedModuleTrace.cpp
@@ -65,6 +65,8 @@ struct LoadedModuleTraceFormat {
   unsigned Version;
   Identifier Name;
   std::string Arch;
+  std::string LanguageMode;
+  std::vector<StringRef> EnabledLanguageFeatures;
   bool StrictMemorySafety;
   std::vector<SwiftModuleTraceInfo> SwiftModules;
   std::vector<SwiftMacroTraceInfo> SwiftMacros;
@@ -107,6 +109,11 @@ template <> struct ObjectTraits<LoadedModuleTraceFormat> {
 
     out.mapRequired("arch", contents.Arch);
 
+    out.mapRequired("languageMode", contents.LanguageMode);
+
+    out.mapRequired("enabledLanguageFeatures",
+                    contents.EnabledLanguageFeatures);
+
     out.mapRequired("strictMemorySafety", contents.StrictMemorySafety);
 
     // The 'swiftmodules' key is kept for backwards compatibility.
@@ -723,6 +730,38 @@ computeSwiftMacroTraceInfo(ASTContext &ctx, const DependencyTracker &depTracker,
       });
 }
 
+static void computeEnabledFeatures(ASTContext &ctx,
+                                   std::vector<StringRef> &enabledFeatures) {
+  struct FeatureAndName {
+    Feature feature;
+    StringRef name;
+  };
+
+  static const FeatureAndName features[] = {
+#define FEATURE_ENTRY(FeatureName) {Feature::FeatureName, #FeatureName},
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Version)
+#define EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)                     \
+  FEATURE_ENTRY(FeatureName)
+#define UPCOMING_FEATURE(FeatureName, SENumber, Version)                       \
+  FEATURE_ENTRY(FeatureName)
+#define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Version)              \
+  FEATURE_ENTRY(FeatureName)
+#include "swift/Basic/Features.def"
+  };
+
+  for (auto &featureAndName : features) {
+    if (ctx.LangOpts.hasFeature(featureAndName.feature))
+      enabledFeatures.push_back(featureAndName.name);
+  }
+
+  // FIXME: It would be nice if the features were added in sorted order instead.
+  // However, std::sort is not constexpr until C++20.
+  std::sort(enabledFeatures.begin(), enabledFeatures.end(),
+            [](const StringRef &lhs, const StringRef &rhs) -> bool {
+              return lhs.compare(rhs) < 0;
+            });
+}
+
 // [NOTE: Bailing-vs-crashing-in-trace-emission] There are certain edge cases
 // in trace emission where an invariant that you think should hold does not hold
 // in practice. For example, sometimes we have seen modules without any
@@ -785,12 +824,18 @@ bool swift::emitLoadedModuleTraceIfNeeded(ModuleDecl *mainModule,
   std::vector<SwiftMacroTraceInfo> swiftMacros;
   computeSwiftMacroTraceInfo(ctxt, *depTracker, swiftMacros);
 
+  std::vector<StringRef> enabledFeatures;
+  computeEnabledFeatures(ctxt, enabledFeatures);
+
   LoadedModuleTraceFormat trace = {
       /*version=*/LoadedModuleTraceFormat::CurrentVersion,
       /*name=*/mainModule->getName(),
       /*arch=*/ctxt.LangOpts.Target.getArchName().str(),
+      ctxt.LangOpts.EffectiveLanguageVersion.asAPINotesVersionString(),
+      enabledFeatures,
       mainModule ? mainModule->strictMemorySafety() : false,
-      swiftModules, swiftMacros};
+      swiftModules,
+      swiftMacros};
 
   // raw_fd_ostream is unbuffered, and we may have multiple processes writing,
   // so first write to memory and then dump the buffer to the trace file.
@@ -829,9 +874,9 @@ bool swift::emitLoadedModuleTraceIfNeeded(ModuleDecl *mainModule,
 class ObjcMethodReferenceCollector: public SourceEntityWalker {
   unsigned CurrentFileID;
   llvm::DenseMap<const clang::ObjCMethodDecl*, unsigned> results;
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef,
-                          Type T, ReferenceMetaData Data) override {
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type T,
+                          ReferenceMetaData Data) override {
     if (!Range.isValid())
       return true;
     if (auto *clangD = dyn_cast_or_null<clang::ObjCMethodDecl>(D->getClangDecl()))
diff --git a/lib/IDE/AfterPoundExprCompletion.cpp b/lib/IDE/AfterPoundExprCompletion.cpp
index a97b1b55d7f36..0a5172f5bba70 100644
--- a/lib/IDE/AfterPoundExprCompletion.cpp
+++ b/lib/IDE/AfterPoundExprCompletion.cpp
@@ -13,7 +13,6 @@
 #include "swift/IDE/AfterPoundExprCompletion.h"
 #include "swift/IDE/CodeCompletion.h"
 #include "swift/IDE/CompletionLookup.h"
-#include "swift/Sema/CompletionContextFinder.h"
 #include "swift/Sema/ConstraintSystem.h"
 #include "swift/Sema/IDETypeChecking.h"
 
@@ -28,7 +27,7 @@ void AfterPoundExprCompletion::sawSolutionImpl(const constraints::Solution &S) {
 
   // If ExpectedTy is a duplicate of any other result, ignore this solution.
   auto IsEqual = [&](const Result &R) {
-    return R.ExpectedTy->isEqual(ExpectedTy);
+    return nullableTypesEqual(R.ExpectedTy, ExpectedTy);
   };
   if (!llvm::any_of(Results, IsEqual)) {
     bool IsImpliedResult = isImpliedResult(S, CompletionExpr);
diff --git a/lib/IDE/ArgumentCompletion.cpp b/lib/IDE/ArgumentCompletion.cpp
index 77828265f7b9b..1b3ee86346e08 100644
--- a/lib/IDE/ArgumentCompletion.cpp
+++ b/lib/IDE/ArgumentCompletion.cpp
@@ -10,11 +10,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "swift/Basic/Assertions.h"
 #include "swift/IDE/ArgumentCompletion.h"
+#include "swift/AST/Types.h"
+#include "swift/Basic/Assertions.h"
 #include "swift/IDE/CodeCompletion.h"
 #include "swift/IDE/CompletionLookup.h"
 #include "swift/IDE/SelectedOverloadInfo.h"
+#include "swift/IDE/SignatureHelp.h"
 #include "swift/Sema/ConstraintSystem.h"
 #include "swift/Sema/IDETypeChecking.h"
 
@@ -60,9 +62,9 @@ bool ArgumentTypeCheckCompletionCallback::addPossibleParams(
       // a multitple trailing closure label but the parameter is not a function
       // type. Since we only allow labeled trailing closures after the first
       // trailing closure, we cannot pass an argument for this parameter.
-      // If the parameter is required, stop here since we cannot pass an argument
-      // for the parameter. If it's optional, keep looking for more trailing
-      // closures that can be passed.
+      // If the parameter is required, stop here since we cannot pass an
+      // argument for the parameter. If it's optional, keep looking for more
+      // trailing closures that can be passed.
       if (Required) {
         break;
       } else {
@@ -95,7 +97,8 @@ bool ArgumentTypeCheckCompletionCallback::addPossibleParams(
 static bool hasParentCallLikeExpr(Expr *E, ConstraintSystem &CS) {
   E = CS.getParentExpr(E);
   while (E) {
-    if (E->getArgs() || isa<ParenExpr>(E) || isa<TupleExpr>(E) || isa<CollectionExpr>(E)) {
+    if (E->getArgs() || isa<ParenExpr>(E) || isa<TupleExpr>(E) ||
+        isa<CollectionExpr>(E)) {
       return true;
     }
     E = CS.getParentExpr(E);
@@ -103,6 +106,55 @@ static bool hasParentCallLikeExpr(Expr *E, ConstraintSystem &CS) {
   return false;
 }
 
+/// The callee can be a double-applied function in the second apply (e.g.
+/// `f()(|)`). In that case, the normal callee locator will not be able to find
+/// a selected overload since an overload has been selected for the first apply
+/// but not the second. We try to find the function's declaration and type
+/// if it turns out to be a double apply.
+static std::optional<std::pair<ValueDecl *, AnyFunctionType *>>
+tryResolveDoubleAppliedFunction(CallExpr *OuterCall, const Solution &S) {
+  if (!OuterCall)
+    return std::nullopt;
+
+  auto *InnerCall = dyn_cast<CallExpr>(OuterCall->getSemanticFn());
+  if (!InnerCall)
+    return std::nullopt;
+
+  auto &CS = S.getConstraintSystem();
+  auto *InnerCallLocator = CS.getConstraintLocator(InnerCall);
+  auto Overload = S.getCalleeOverloadChoiceIfAvailable(InnerCallLocator);
+  if (!Overload)
+    return std::nullopt;
+
+  if (!Overload->choice.isDecl())
+    return std::nullopt;
+
+  auto FuncRefInfo = Overload->choice.getFunctionRefInfo();
+  if (!FuncRefInfo.isDoubleApply())
+    return std::nullopt;
+
+  auto CalleeTy = S.simplifyTypeForCodeCompletion(Overload->adjustedOpenedType)
+                      ->getAs<AnyFunctionType>();
+  if (!CalleeTy)
+    return std::nullopt;
+
+  auto *FuncTy = CalleeTy->getResult()->getAs<AnyFunctionType>();
+  if (!FuncTy)
+    return std::nullopt;
+
+  auto *VD = Overload->choice.getDecl();
+  auto BaseTy = Overload->choice.getBaseType();
+  bool IsOuterCallImplicitlyCurried =
+      VD->isInstanceMember() && !doesMemberRefApplyCurriedSelf(BaseTy, VD);
+
+  // The function declaration is only relevant if the function is an implicitly
+  // curried instance method.
+  if (IsOuterCallImplicitlyCurried)
+    return std::make_pair(Overload->choice.getDecl(), FuncTy);
+
+  return std::make_pair(nullptr, FuncTy);
+}
+
 void ArgumentTypeCheckCompletionCallback::sawSolutionImpl(const Solution &S) {
   Type ExpectedTy = getTypeForCompletion(S, CompletionExpr);
 
@@ -148,7 +200,9 @@ void ArgumentTypeCheckCompletionCallback::sawSolutionImpl(const Solution &S) {
       ExpectedCallType = ContextualType;
     }
   }
-  if (ExpectedCallType && ExpectedCallType->hasUnresolvedType()) {
+  if (ExpectedCallType &&
+      (ExpectedCallType->hasError() ||
+       ExpectedCallType->hasUnboundGenericType())) {
     ExpectedCallType = Type();
   }
   
@@ -228,11 +282,24 @@ void ArgumentTypeCheckCompletionCallback::sawSolutionImpl(const Solution &S) {
   llvm::SmallDenseMap<const VarDecl *, Type> SolutionSpecificVarTypes;
   getSolutionSpecificVarTypes(S, SolutionSpecificVarTypes);
 
+  ValueDecl *FuncD = nullptr;
   AnyFunctionType *FuncTy = nullptr;
+  bool IsSecondApply = false;
   if (Info.ValueTy) {
-    FuncTy = Info.ValueTy->lookThroughAllOptionalTypes()->getAs<AnyFunctionType>();
+    FuncD = Info.getValue();
+    FuncTy =
+        Info.ValueTy->lookThroughAllOptionalTypes()->getAs<AnyFunctionType>();
+  } else if (auto Result = tryResolveDoubleAppliedFunction(
+                 dyn_cast<CallExpr>(ParentCall), S)) {
+    FuncD = Result->first;
+    FuncTy = Result->second;
+    IsSecondApply = true;
   }
 
+  bool IsImplicitlyCurried =
+      Info.ValueRef && Info.ValueRef.getDecl()->isInstanceMember() &&
+      !doesMemberRefApplyCurriedSelf(Info.BaseTy, Info.ValueRef.getDecl());
+
   // Determine which parameters are optional. We need to do this in
   // `sawSolutionImpl` because it accesses the substitution map in
   // `Info.ValueRef`. This substitution map might contain type variables that
@@ -244,9 +311,7 @@ void ArgumentTypeCheckCompletionCallback::sawSolutionImpl(const Solution &S) {
     for (auto Idx : range(0, ParamsToPass.size())) {
       bool Optional = false;
       if (Info.ValueRef) {
-        if (Info.ValueRef.getDecl()->isInstanceMember() &&
-            !doesMemberRefApplyCurriedSelf(Info.BaseTy,
-                                           Info.ValueRef.getDecl())) {
+        if (IsImplicitlyCurried) {
           // We are completing in an unapplied instance function, eg.
           // struct TestStatic {
           //   func method() ->  Void {}
@@ -284,10 +349,11 @@ void ArgumentTypeCheckCompletionCallback::sawSolutionImpl(const Solution &S) {
   }
 
   Results.push_back(
-      {ExpectedTy,  ExpectedCallType, isa<SubscriptExpr>(ParentCall),
-       Info.getValue(), FuncTy, ArgIdx, ParamIdx, std::move(ClaimedParams),
-       IsNoninitialVariadic, IncludeSignature, Info.BaseTy, HasLabel, FirstTrailingClosureIndex,
-       IsAsync, DeclParamIsOptional, SolutionSpecificVarTypes});
+      {ExpectedTy, ExpectedCallType, isa<SubscriptExpr>(ParentCall), FuncD,
+       FuncTy, ArgIdx, ParamIdx, std::move(ClaimedParams), IsNoninitialVariadic,
+       IncludeSignature, Info.BaseTy, HasLabel, FirstTrailingClosureIndex,
+       IsAsync, IsImplicitlyCurried, IsSecondApply, DeclParamIsOptional,
+       SolutionSpecificVarTypes});
 }
 
 void ArgumentTypeCheckCompletionCallback::computeShadowedDecls(
@@ -430,3 +496,19 @@ void ArgumentTypeCheckCompletionCallback::collectResults(
                            *Lookup.getExpectedTypeContext(),
                            Lookup.canCurrDeclContextHandleAsync());
 }
+
+void ArgumentTypeCheckCompletionCallback::getSignatures(
+    SourceLoc Loc, DeclContext *DC, SmallVectorImpl<Signature> &Signatures) {
+  SmallPtrSet<ValueDecl *, 4> ShadowedDecls;
+  computeShadowedDecls(ShadowedDecls);
+
+  for (auto &Result : Results) {
+    // Only show signature if the function isn't overridden.
+    if (!Result.FuncTy || ShadowedDecls.contains(Result.FuncD))
+      continue;
+
+    Signatures.push_back({Result.IsSubscript, Result.IsImplicitlyCurried,
+                          Result.IsSecondApply, Result.FuncD, Result.FuncTy,
+                          Result.ExpectedType, Result.ParamIdx});
+  }
+}
diff --git a/lib/IDE/CMakeLists.txt b/lib/IDE/CMakeLists.txt
index 7b03bb48cc2a4..cd6387ada7c0a 100644
--- a/lib/IDE/CMakeLists.txt
+++ b/lib/IDE/CMakeLists.txt
@@ -12,11 +12,14 @@ add_swift_host_library(swiftIDE STATIC
   CodeCompletionResultPrinter.cpp
   CodeCompletionResultType.cpp
   CodeCompletionString.cpp
+  CodeCompletionStringBuilder.cpp
   CodeCompletionStringPrinter.cpp
   CommentConversion.cpp
   CompletionLookup.cpp
   CompletionOverrideLookup.cpp
   ConformingMethodList.cpp
+  SignatureHelp.cpp
+  SignatureHelpFormatter.cpp
   CursorInfo.cpp
   ExprCompletion.cpp
   ExprContextAnalysis.cpp
@@ -46,6 +49,14 @@ target_link_libraries(swiftIDE PRIVATE
   swiftParse
   swiftSema)
 
+# Clang dependencies. These are private because IDE's public
+# interface does not use Clang symbols.
+target_link_libraries(swiftIDE PRIVATE
+  clangAST
+  clangBasic
+  clangIndex
+  clangLex)
+
 if (SWIFT_BUILD_SWIFT_SYNTAX)
   target_link_libraries(swiftIDE PRIVATE
     swiftIDEUtilsBridging
diff --git a/lib/IDE/CodeCompletion.cpp b/lib/IDE/CodeCompletion.cpp
index bcca73daaca5a..29fd3589ad769 100644
--- a/lib/IDE/CodeCompletion.cpp
+++ b/lib/IDE/CodeCompletion.cpp
@@ -14,6 +14,7 @@
 #include "CodeCompletionDiagnostics.h"
 #include "CodeCompletionResultBuilder.h"
 #include "ExprContextAnalysis.h"
+#include "ReadyForTypeCheckingCallback.h"
 #include "swift/AST/ASTPrinter.h"
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/Comment.h"
@@ -105,7 +106,7 @@ std::string swift::ide::removeCodeCompletionTokens(
 namespace {
 
 class CodeCompletionCallbacksImpl : public CodeCompletionCallbacks,
-                                    public DoneParsingCallback {
+                                    public ReadyForTypeCheckingCallback {
   CodeCompletionContext &CompletionContext;
   CodeCompletionConsumer &Consumer;
   CodeCompletionExpr *CodeCompleteTokenExpr = nullptr;
@@ -175,25 +176,6 @@ class CodeCompletionCallbacksImpl : public CodeCompletionCallbacks,
 
   /// \returns true on success, false on failure.
   bool typecheckParsedType() {
-    // If the type appeared inside an extension, make sure that extension has
-    // been bound.
-    auto SF = CurDeclContext->getParentSourceFile();
-    auto visitTopLevelDecl = [&](Decl *D) {
-      if (auto ED = dyn_cast<ExtensionDecl>(D)) {
-        if (ED->getSourceRange().contains(ParsedTypeLoc.getLoc())) {
-          ED->computeExtendedNominal();
-        }
-      }
-    };
-    for (auto item : SF->getTopLevelItems()) {
-      if (auto D = item.dyn_cast<Decl *>()) {
-        visitTopLevelDecl(D);
-      }
-    }
-    for (auto *D : SF->getHoistedDecls()) {
-      visitTopLevelDecl(D);
-    }
-
     assert(ParsedTypeLoc.getTypeRepr() && "should have a TypeRepr");
     if (ParsedTypeLoc.wasValidated() && !ParsedTypeLoc.isError()) {
       return true;
@@ -233,8 +215,8 @@ class CodeCompletionCallbacksImpl : public CodeCompletionCallbacks,
   CodeCompletionCallbacksImpl(Parser &P,
                               CodeCompletionContext &CompletionContext,
                               CodeCompletionConsumer &Consumer)
-      : CodeCompletionCallbacks(P), DoneParsingCallback(),
-        CompletionContext(CompletionContext), Consumer(Consumer) {}
+      : CodeCompletionCallbacks(P), CompletionContext(CompletionContext),
+        Consumer(Consumer) {}
 
   void setAttrTargetDeclKind(std::optional<DeclKind> DK) override {
     if (DK == DeclKind::PatternBinding)
@@ -283,6 +265,7 @@ class CodeCompletionCallbacksImpl : public CodeCompletionCallbacks,
 
   void completePoundAvailablePlatform() override;
   void completeImportDecl(ImportPath::Builder &Path) override;
+  void completeUsingDecl() override;
   void completeUnresolvedMember(CodeCompletionExpr *E,
                                 SourceLoc DotLoc) override;
   void completeCallArg(CodeCompletionExpr *E) override;
@@ -308,7 +291,7 @@ class CodeCompletionCallbacksImpl : public CodeCompletionCallbacks,
   void completeTypeAttrInheritanceBeginning() override;
   void completeOptionalBinding() override;
 
-  void doneParsing(SourceFile *SrcFile) override;
+  void readyForTypeChecking(SourceFile *SrcFile) override;
 
 private:
   void addKeywords(CodeCompletionResultSink &Sink, bool MaybeFuncBody);
@@ -550,6 +533,11 @@ void CodeCompletionCallbacksImpl::completeImportDecl(
   Path.pop_back();
 }
 
+void CodeCompletionCallbacksImpl::completeUsingDecl() {
+  Kind = CompletionKind::Using;
+  CurDeclContext = P.CurDeclContext;
+}
+
 void CodeCompletionCallbacksImpl::completeUnresolvedMember(CodeCompletionExpr *E,
     SourceLoc DotLoc) {
   Kind = CompletionKind::UnresolvedMember;
@@ -895,13 +883,13 @@ static void addKeywordsAfterReturn(CodeCompletionResultSink &Sink, DeclContext *
       // Note that `TypeContext` must stay alive for the duration of
       // `~CodeCodeCompletionResultBuilder()`.
       ExpectedTypeContext TypeContext;
-      TypeContext.setPossibleTypes({resultType});
+      TypeContext.setPossibleTypes({DC->mapTypeIntoContext(resultType)});
 
       CodeCompletionResultBuilder Builder(Sink, CodeCompletionResultKind::Literal,
                                           SemanticContextKind::None);
       Builder.setLiteralKind(CodeCompletionLiteralKind::NilLiteral);
       Builder.addKeyword("nil");
-      Builder.addTypeAnnotation(resultType, {});
+      Builder.addTypeAnnotation(resultType, PrintOptions());
       Builder.setResultTypes(resultType);
       Builder.setTypeContext(TypeContext, DC);
     }
@@ -990,6 +978,7 @@ void CodeCompletionCallbacksImpl::addKeywords(CodeCompletionResultSink &Sink,
   case CompletionKind::AttributeBegin:
   case CompletionKind::PoundAvailablePlatform:
   case CompletionKind::Import:
+  case CompletionKind::Using:
   case CompletionKind::UnresolvedMember:
   case CompletionKind::AfterPoundExpr:
   case CompletionKind::AfterPoundDirective:
@@ -1478,27 +1467,15 @@ void CodeCompletionCallbacksImpl::typeCheckWithLookup(
       ASTNode Call = CallExpr::create(
           CurDeclContext->getASTContext(), AttrWithCompletion->getTypeExpr(),
           AttrWithCompletion->getArgs(), /*implicit=*/true);
-      typeCheckContextAt(
+      swift::typeCheckASTNodeAtLoc(
           TypeCheckASTNodeAtLocContext::node(CurDeclContext, Call),
           CompletionLoc);
     }
   } else {
-    typeCheckContextAt(
+    swift::typeCheckASTNodeAtLoc(
         TypeCheckASTNodeAtLocContext::declContext(CurDeclContext),
         CompletionLoc);
   }
-
-  // This (hopefully) only happens in cases where the expression isn't
-  // typechecked during normal compilation either (e.g. member completion in a
-  // switch case where there control expression is invalid). Having normal
-  // typechecking still resolve even these cases would be beneficial for
-  // tooling in general though.
-  if (!Lookup.gotCallback()) {
-    if (Context.TypeCheckerOpts.DebugConstraintSolver) {
-      llvm::errs() << "--- Fallback typecheck for code completion ---\n";
-    }
-    Lookup.fallbackTypeCheck(CurDeclContext);
-  }
 }
 
 void CodeCompletionCallbacksImpl::postfixCompletion(SourceLoc CompletionLoc,
@@ -1544,8 +1521,9 @@ void CodeCompletionCallbacksImpl::postfixCompletion(SourceLoc CompletionLoc,
 
       llvm::SaveAndRestore<TypeCheckCompletionCallback *> CompletionCollector(
           Context.CompletionCallback, &Lookup);
-      typeCheckContextAt(TypeCheckASTNodeAtLocContext::node(CurDeclContext, AE),
-                         CompletionLoc);
+      swift::typeCheckASTNodeAtLoc(
+          TypeCheckASTNodeAtLocContext::node(CurDeclContext, AE),
+          CompletionLoc);
       Lookup.collectResults(/*IsLabeledTrailingClosure=*/true, CompletionLoc,
                             CurDeclContext, CompletionContext);
     }
@@ -1645,7 +1623,7 @@ void CodeCompletionCallbacksImpl::afterPoundCompletion(SourceLoc CompletionLoc,
   Consumer.handleResults(CompletionContext);
 }
 
-void CodeCompletionCallbacksImpl::doneParsing(SourceFile *SrcFile) {
+void CodeCompletionCallbacksImpl::readyForTypeChecking(SourceFile *SrcFile) {
   CompletionContext.CodeCompletionKind = Kind;
 
   if (Kind == CompletionKind::None) {
@@ -1704,7 +1682,7 @@ void CodeCompletionCallbacksImpl::doneParsing(SourceFile *SrcFile) {
 
   if (Kind != CompletionKind::TypeSimpleWithDot) {
     // Type member completion does not need a type-checked AST.
-    typeCheckContextAt(
+    swift::typeCheckASTNodeAtLoc(
         TypeCheckASTNodeAtLocContext::declContext(CurDeclContext),
         ParsedExpr ? ParsedExpr->getLoc()
                    : CurDeclContext->getASTContext()
@@ -1915,7 +1893,10 @@ void CodeCompletionCallbacksImpl::doneParsing(SourceFile *SrcFile) {
       Lookup.addImportModuleNames();
     break;
   }
-
+  case CompletionKind::Using: {
+    Lookup.addUsingSpecifiers();
+    break;
+  }
   case CompletionKind::AfterPoundDirective: {
     addPoundDirectives(CompletionContext.getResultSink());
 
diff --git a/lib/IDE/CodeCompletionCache.cpp b/lib/IDE/CodeCompletionCache.cpp
index d8a4e4e84ebe8..f41299780b820 100644
--- a/lib/IDE/CodeCompletionCache.cpp
+++ b/lib/IDE/CodeCompletionCache.cpp
@@ -244,6 +244,7 @@ static bool readCachedModule(llvm::MemoryBuffer *in,
     auto diagMessageIndex = read32le(cursor);
     auto filterNameIndex = read32le(cursor);
     auto nameForDiagnosticsIndex = read32le(cursor);
+    auto swiftUSRIndex = read32le(cursor);
 
     auto assocUSRCount = read32le(cursor);
     SmallVector<NullTerminatedStringRef, 4> assocUSRs;
@@ -264,12 +265,13 @@ static bool readCachedModule(llvm::MemoryBuffer *in,
     auto diagMessage = getString(diagMessageIndex);
     auto filterName = getString(filterNameIndex);
     auto nameForDiagnostics = getString(nameForDiagnosticsIndex);
+    auto swiftUSR = getString(swiftUSRIndex);
 
     ContextFreeCodeCompletionResult *result =
         new (*V.Allocator) ContextFreeCodeCompletionResult(
-            kind, associatedKind, opKind, roles, isSystem,
-                                                           hasAsyncAlternative, string, moduleName, briefDocComment,
-            llvm::ArrayRef(assocUSRs).copy(*V.Allocator),
+            kind, associatedKind, opKind, roles, isSystem, hasAsyncAlternative,
+            string, moduleName, briefDocComment,
+            llvm::ArrayRef(assocUSRs).copy(*V.Allocator), swiftUSR,
             CodeCompletionResultType(resultTypes), notRecommended, diagSeverity,
             diagMessage, filterName, nameForDiagnostics);
 
@@ -430,11 +432,12 @@ static void writeCachedModule(llvm::raw_ostream &out,
       LE.write(static_cast<uint8_t>(R->hasAsyncAlternative()));
       LE.write(
           static_cast<uint32_t>(addCompletionString(R->getCompletionString())));
-      LE.write(addString(R->getModuleName()));      // index into strings
-      LE.write(addString(R->getBriefDocComment())); // index into strings
-      LE.write(addString(R->getDiagnosticMessage())); // index into strings
-      LE.write(addString(R->getFilterName())); // index into strings
+      LE.write(addString(R->getModuleName()));         // index into strings
+      LE.write(addString(R->getBriefDocComment()));    // index into strings
+      LE.write(addString(R->getDiagnosticMessage()));  // index into strings
+      LE.write(addString(R->getFilterName()));         // index into strings
       LE.write(addString(R->getNameForDiagnostics())); // index into strings
+      LE.write(addString(R->getSwiftUSR()));           // index into strings
 
       LE.write(static_cast<uint32_t>(R->getAssociatedUSRs().size()));
       for (unsigned i = 0; i < R->getAssociatedUSRs().size(); ++i) {
diff --git a/lib/IDE/CodeCompletionContext.cpp b/lib/IDE/CodeCompletionContext.cpp
index 78320962ed98d..f08536368eddb 100644
--- a/lib/IDE/CodeCompletionContext.cpp
+++ b/lib/IDE/CodeCompletionContext.cpp
@@ -110,10 +110,12 @@ static MutableArrayRef<CodeCompletionResult *> copyCodeCompletionResults(
             ContextualNotRecommendedReason::None,
             CanCurrDeclContextHandleAsync);
 
+    ASTContext *Ctx = DC ? &DC->getASTContext() : nullptr;
     auto contextualResult = new (*targetSink.Allocator) CodeCompletionResult(
-        *contextFreeResult, SemanticContextKind::OtherModule,
-        CodeCompletionFlair(),
-        /*numBytesToErase=*/0, typeRelation, notRecommendedReason);
+        *contextFreeResult, Ctx, SemanticContextKind::OtherModule,
+        CodeCompletionFlair(), /*numBytesToErase=*/0, typeRelation,
+        notRecommendedReason);
+
     targetSink.Results.push_back(contextualResult);
   }
 
@@ -145,6 +147,7 @@ void CodeCompletionContext::addResultsFromModules(
       Sink.addInitsToTopLevel = getAddInitsToTopLevel();
       Sink.includeObjectLiterals = includeObjectLiterals();
       Sink.addCallWithNoDefaultArgs = addCallWithNoDefaultArgs();
+      Sink.verifyUSRToDecl = verifyUSRToDecl();
       Sink.setProduceContextFreeResults((*V)->USRTypeArena);
       lookupCodeCompletionResultsFromModule(Sink, R.TheModule, R.Key.AccessPath,
                                             R.Key.ResultsHaveLeadingDot, SF);
diff --git a/lib/IDE/CodeCompletionResult.cpp b/lib/IDE/CodeCompletionResult.cpp
index 3a48f610ca8d9..c5ed4323b90b2 100644
--- a/lib/IDE/CodeCompletionResult.cpp
+++ b/lib/IDE/CodeCompletionResult.cpp
@@ -12,6 +12,7 @@
 
 #include "swift/IDE/CodeCompletionResult.h"
 #include "CodeCompletionDiagnostics.h"
+#include "swift/AST/ASTDemangler.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/Module.h"
 #include "swift/Basic/Assertions.h"
@@ -135,7 +136,8 @@ ContextFreeCodeCompletionResult *
 ContextFreeCodeCompletionResult::createPatternOrBuiltInOperatorResult(
     CodeCompletionResultSink &Sink, CodeCompletionResultKind Kind,
     CodeCompletionString *CompletionString,
-    CodeCompletionOperatorKind KnownOperatorKind, NullTerminatedStringRef BriefDocComment,
+    CodeCompletionOperatorKind KnownOperatorKind,
+    NullTerminatedStringRef BriefDocComment,
     CodeCompletionResultType ResultType,
     ContextFreeNotRecommendedReason NotRecommended,
     CodeCompletionDiagnosticSeverity DiagnosticSeverity,
@@ -151,11 +153,10 @@ ContextFreeCodeCompletionResult::createPatternOrBuiltInOperatorResult(
   }
   return new (Sink.getAllocator()) ContextFreeCodeCompletionResult(
       Kind, /*AssociatedKind=*/0, KnownOperatorKind, /*MacroRoles=*/{},
-      /*IsSystem=*/false, /*HasAsyncAlternative=*/false,
-      CompletionString,
+      /*IsSystem=*/false, /*HasAsyncAlternative=*/false, CompletionString,
       /*ModuleName=*/"", BriefDocComment,
-      /*AssociatedUSRs=*/{}, ResultType, NotRecommended, DiagnosticSeverity,
-      DiagnosticMessage,
+      /*AssociatedUSRs=*/{}, /*SwiftUSR=*/"", ResultType, NotRecommended,
+      DiagnosticSeverity, DiagnosticMessage,
       getCodeCompletionResultFilterName(CompletionString, Sink.getAllocator()),
       NameForDiagnostics);
 }
@@ -173,8 +174,8 @@ ContextFreeCodeCompletionResult::createKeywordResult(
       CodeCompletionResultKind::Keyword, static_cast<uint8_t>(Kind),
       CodeCompletionOperatorKind::None, /*MacroRoles=*/{},
       /*IsSystem=*/false, /*HasAsyncAlternative=*/false, CompletionString,
-      /*ModuleName=*/"", BriefDocComment,
-      /*AssociatedUSRs=*/{}, ResultType, ContextFreeNotRecommendedReason::None,
+      /*ModuleName=*/"", BriefDocComment, /*AssociatedUSRs=*/{},
+      /*SwiftUSR=*/"", ResultType, ContextFreeNotRecommendedReason::None,
       CodeCompletionDiagnosticSeverity::None, /*DiagnosticMessage=*/"",
       getCodeCompletionResultFilterName(CompletionString, Sink.getAllocator()),
       /*NameForDiagnostics=*/"");
@@ -191,11 +192,10 @@ ContextFreeCodeCompletionResult::createLiteralResult(
   return new (Sink.getAllocator()) ContextFreeCodeCompletionResult(
       CodeCompletionResultKind::Literal, static_cast<uint8_t>(LiteralKind),
       CodeCompletionOperatorKind::None, /*MacroRoles=*/{},
-      /*IsSystem=*/false, /*HasAsyncAlternative=*/false,
-      CompletionString,
-      /*ModuleName=*/"",
-      /*BriefDocComment=*/"",
-      /*AssociatedUSRs=*/{}, ResultType, ContextFreeNotRecommendedReason::None,
+      /*IsSystem=*/false, /*HasAsyncAlternative=*/false, CompletionString,
+      /*ModuleName=*/"", /*BriefDocComment=*/"",
+      /*AssociatedUSRs=*/{}, /*SwiftUSR=*/"", ResultType,
+      ContextFreeNotRecommendedReason::None,
       CodeCompletionDiagnosticSeverity::None, /*DiagnosticMessage=*/"",
       getCodeCompletionResultFilterName(CompletionString, Sink.getAllocator()),
       /*NameForDiagnostics=*/"");
@@ -222,7 +222,7 @@ ContextFreeCodeCompletionResult::createDeclResult(
     const Decl *AssociatedDecl, bool HasAsyncAlternative,
     NullTerminatedStringRef ModuleName, NullTerminatedStringRef BriefDocComment,
     ArrayRef<NullTerminatedStringRef> AssociatedUSRs,
-    CodeCompletionResultType ResultType,
+    NullTerminatedStringRef SwiftUSR, CodeCompletionResultType ResultType,
     ContextFreeNotRecommendedReason NotRecommended,
     CodeCompletionDiagnosticSeverity DiagnosticSeverity,
     NullTerminatedStringRef DiagnosticMessage) {
@@ -234,8 +234,8 @@ ContextFreeCodeCompletionResult::createDeclResult(
       CodeCompletionResultKind::Declaration,
       static_cast<uint8_t>(getCodeCompletionDeclKind(AssociatedDecl)),
       CodeCompletionOperatorKind::None, getCompletionMacroRoles(AssociatedDecl),
-      getDeclIsSystem(AssociatedDecl), HasAsyncAlternative,
-      CompletionString, ModuleName, BriefDocComment, AssociatedUSRs, ResultType,
+      getDeclIsSystem(AssociatedDecl), HasAsyncAlternative, CompletionString,
+      ModuleName, BriefDocComment, AssociatedUSRs, SwiftUSR, ResultType,
       NotRecommended, DiagnosticSeverity, DiagnosticMessage,
       getCodeCompletionResultFilterName(CompletionString, Sink.getAllocator()),
       /*NameForDiagnostics=*/getDeclNameForDiagnostics(AssociatedDecl, Sink));
@@ -315,6 +315,7 @@ ContextFreeCodeCompletionResult::getCodeCompletionDeclKind(const Decl *D) {
   case DeclKind::OpaqueType:
   case DeclKind::BuiltinTuple:
   case DeclKind::MacroExpansion:
+  case DeclKind::Using:
     llvm_unreachable("not expecting such a declaration result");
   case DeclKind::Module:
     return CodeCompletionDeclKind::Module;
@@ -435,11 +436,23 @@ ContextFreeCodeCompletionResult::calculateContextualTypeRelation(
 
 // MARK: - CodeCompletionResult
 
+const Decl *CodeCompletionResult::getAssociatedDecl() const {
+  if (auto *Ctx = DeclOrCtx.dyn_cast<ASTContext *>()) {
+    auto SwiftUSR = ContextFree.getSwiftUSR();
+    if (SwiftUSR.empty())
+      return nullptr;
+
+    DeclOrCtx = Demangle::getDeclForUSR(*Ctx, SwiftUSR);
+  }
+
+  return DeclOrCtx.dyn_cast<const Decl *>();
+}
+
 CodeCompletionResult *
 CodeCompletionResult::withFlair(CodeCompletionFlair NewFlair,
                                 CodeCompletionResultSink &Sink) const {
   return new (*Sink.Allocator)
-      CodeCompletionResult(ContextFree, SemanticContext, NewFlair,
+      CodeCompletionResult(ContextFree, DeclOrCtx, SemanticContext, NewFlair,
                            NumBytesToErase, TypeDistance, NotRecommended);
 }
 
@@ -448,9 +461,9 @@ CodeCompletionResult::withContextFreeResultSemanticContextAndFlair(
     const ContextFreeCodeCompletionResult &NewContextFree,
     SemanticContextKind NewSemanticContext, CodeCompletionFlair NewFlair,
     CodeCompletionResultSink &Sink) const {
-  return new (*Sink.Allocator)
-      CodeCompletionResult(NewContextFree, NewSemanticContext, NewFlair,
-                           NumBytesToErase, TypeDistance, NotRecommended);
+  return new (*Sink.Allocator) CodeCompletionResult(
+      NewContextFree, DeclOrCtx, NewSemanticContext, NewFlair, NumBytesToErase,
+      TypeDistance, NotRecommended);
 }
 
 std::pair<CodeCompletionDiagnosticSeverity, NullTerminatedStringRef>
diff --git a/lib/IDE/CodeCompletionResultBuilder.cpp b/lib/IDE/CodeCompletionResultBuilder.cpp
index 590fd892ff49d..2aae021605fb3 100644
--- a/lib/IDE/CodeCompletionResultBuilder.cpp
+++ b/lib/IDE/CodeCompletionResultBuilder.cpp
@@ -13,10 +13,12 @@
 #include "CodeCompletionResultBuilder.h"
 #include "CodeCompletionDiagnostics.h"
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/ASTDemangler.h"
 #include "swift/AST/USRGeneration.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/IDE/CodeCompletionStringPrinter.h"
+#include "swift/IDE/CommentConversion.h"
 #include "swift/IDE/Utils.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Comment.h"
@@ -80,14 +82,74 @@ copyAssociatedUSRs(llvm::BumpPtrAllocator &Allocator, const Decl *D) {
   return {};
 }
 
-void CodeCompletionResultBuilder::addChunkWithText(
-    CodeCompletionString::Chunk::ChunkKind Kind, StringRef Text) {
-  addChunkWithTextNoCopy(Kind, Text.copy(*Sink.Allocator));
+static NullTerminatedStringRef copySwiftUSR(llvm::BumpPtrAllocator &Allocator,
+                                            const Decl *D) {
+  auto *VD = dyn_cast<ValueDecl>(D);
+  if (!VD || !shouldCopyAssociatedUSRForDecl(VD))
+    return NullTerminatedStringRef();
+
+  SmallString<128> SS;
+  llvm::raw_svector_ostream OS(SS);
+  if (!ide::printValueDeclSwiftUSR(VD, OS))
+    return NullTerminatedStringRef(SS, Allocator);
+
+  return NullTerminatedStringRef();
+}
+
+/// Tries to reconstruct the provided \p D declaration using \c
+/// Demangle::getDeclForUSR and verifies that the declarations match. This only
+/// works if \p D is a \c ValueDecl and \c shouldCopyAssociatedUSRForDecl is
+/// true.
+///
+/// This is intended for testing only.
+static void verifyUSRToDeclReconstruction(const Decl *D) {
+  auto *VD = dyn_cast<ValueDecl>(D);
+  if (!VD)
+    return;
+
+  if (!shouldCopyAssociatedUSRForDecl(VD))
+    return;
+
+  SmallString<128> SwiftUSR;
+
+  llvm::raw_svector_ostream OS(SwiftUSR);
+  if (ide::printValueDeclSwiftUSR(VD, OS)) {
+    ABORT([&](auto &out) {
+      out << "Declaration should have a Swift USR:\n";
+      VD->dump(out);
+    });
+  }
+
+  auto &Ctx = VD->getASTContext();
+  auto *Reconstructed = Demangle::getDeclForUSR(Ctx, SwiftUSR);
+
+  if (!Reconstructed) {
+    ABORT([&](auto &out) {
+      out << "Reconstructed declaration shouldn't be null\n"
+          << "Swift USR: " << SwiftUSR << ", original declaration:\n";
+      VD->dump(out);
+    });
+  }
+
+  if (Reconstructed != VD) {
+    ABORT([&](auto &out) {
+      out << "Reconstructed declaration should match the original one\n"
+          << "Swift USR: " << SwiftUSR << "\n"
+          << "Original declaration:\n";
+      VD->dump(out);
+      out << "Reconstructed declaration:\n";
+      Reconstructed->dump(out);
+    });
+  }
 }
 
 CodeCompletionResult *CodeCompletionResultBuilder::takeResult() {
   auto &Allocator = *Sink.Allocator;
-  auto *CCS = CodeCompletionString::create(Allocator, Chunks);
+  auto *CCS = createCompletionString();
+
+  if (Sink.verifyUSRToDecl && AssociatedDecl) {
+    verifyUSRToDeclReconstruction(AssociatedDecl);
+  }
 
   CodeCompletionDiagnosticSeverity ContextFreeDiagnosticSeverity =
       CodeCompletionDiagnosticSeverity::None;
@@ -125,7 +187,7 @@ CodeCompletionResult *CodeCompletionResultBuilder::takeResult() {
               NullTerminatedStringRef(C->getFullModuleName(), Allocator);
         } else {
           ModuleName = NullTerminatedStringRef(
-              CurrentModule.get<const swift::ModuleDecl *>()->getName().str(),
+              cast<const swift::ModuleDecl *>(CurrentModule)->getName().str(),
               Allocator);
         }
         Sink.LastModule.first = CurrentModule.getOpaqueValue();
@@ -136,7 +198,8 @@ CodeCompletionResult *CodeCompletionResultBuilder::takeResult() {
     ContextFreeResult = ContextFreeCodeCompletionResult::createDeclResult(
         Sink, CCS, AssociatedDecl, HasAsyncAlternative, ModuleName,
         NullTerminatedStringRef(BriefDocComment, Allocator),
-        copyAssociatedUSRs(Allocator, AssociatedDecl), ResultType,
+        copyAssociatedUSRs(Allocator, AssociatedDecl),
+        copySwiftUSR(Allocator, AssociatedDecl), ResultType,
         ContextFreeNotRecReason, ContextFreeDiagnosticSeverity,
         ContextFreeDiagnosticMessage);
     break;
@@ -167,8 +230,9 @@ CodeCompletionResult *CodeCompletionResultBuilder::takeResult() {
     // If the sink only intends to store the context free results in the cache,
     // we don't need to compute any contextual properties.
     return new (Allocator) CodeCompletionResult(
-        *ContextFreeResult, SemanticContextKind::None, CodeCompletionFlair(),
-        /*NumBytesToErase=*/0, CodeCompletionResultTypeRelation::Unrelated,
+        *ContextFreeResult, AssociatedDecl, SemanticContextKind::None,
+        CodeCompletionFlair(), /*NumBytesToErase=*/0,
+        CodeCompletionResultTypeRelation::Unrelated,
         ContextualNotRecommendedReason::None);
   } else {
     assert(
@@ -187,8 +251,8 @@ CodeCompletionResult *CodeCompletionResultBuilder::takeResult() {
             ContextualNotRecReason, CanCurrDeclContextHandleAsync);
 
     return new (Allocator) CodeCompletionResult(
-        *ContextFreeResult, SemanticContext, Flair, NumBytesToErase,
-        typeRelation, notRecommendedReason);
+        *ContextFreeResult, AssociatedDecl, SemanticContext, Flair,
+        NumBytesToErase, typeRelation, notRecommendedReason);
   }
 }
 
@@ -236,201 +300,3 @@ void CodeCompletionResultBuilder::setAssociatedDecl(const Decl *D) {
     setBriefDocComment(AssociatedDecl->getSemanticBriefComment());
   }
 }
-
-void CodeCompletionResultBuilder::addCallArgument(
-    Identifier Name, Identifier LocalName, Type Ty, Type ContextTy,
-    bool IsVarArg, bool IsInOut, bool IsIUO, bool IsAutoClosure,
-    bool IsLabeledTrailingClosure, bool IsForOperator, bool HasDefault) {
-  ++CurrentNestingLevel;
-  using ChunkKind = CodeCompletionString::Chunk::ChunkKind;
-
-  addSimpleChunk(ChunkKind::CallArgumentBegin);
-
-  if (shouldAnnotateResults()) {
-    llvm::SmallString<16> EscapedKeyword;
-    if (!Name.empty()) {
-      addChunkWithText(ChunkKind::CallArgumentName,
-                       escapeKeyword(Name.str(), false, EscapedKeyword));
-      if (!LocalName.empty() && Name != LocalName) {
-        addChunkWithTextNoCopy(ChunkKind::Text, " ");
-        getLastChunk().setIsAnnotation();
-        addChunkWithText(ChunkKind::CallArgumentInternalName,
-                         escapeKeyword(LocalName.str(), false, EscapedKeyword));
-        getLastChunk().setIsAnnotation();
-      }
-      addChunkWithTextNoCopy(ChunkKind::CallArgumentColon, ": ");
-    } else if (!LocalName.empty()) {
-      addChunkWithTextNoCopy(ChunkKind::CallArgumentName, "_");
-      getLastChunk().setIsAnnotation();
-      addChunkWithTextNoCopy(ChunkKind::Text, " ");
-      getLastChunk().setIsAnnotation();
-      addChunkWithText(ChunkKind::CallArgumentInternalName,
-                       escapeKeyword(LocalName.str(), false, EscapedKeyword));
-      addChunkWithTextNoCopy(ChunkKind::CallArgumentColon, ": ");
-    } else if (!IsForOperator) {
-      addChunkWithTextNoCopy(ChunkKind::CallArgumentName, "_");
-      if (!IsLabeledTrailingClosure)
-        getLastChunk().setIsAnnotation();
-      addChunkWithTextNoCopy(ChunkKind::CallArgumentColon, ": ");
-      if (!IsLabeledTrailingClosure)
-        getLastChunk().setIsAnnotation();
-    }
-  } else {
-    llvm::SmallString<16> stash;
-    ChunkKind nameKind;
-    StringRef nameStr;
-    if (!Name.empty()) {
-      nameKind = ChunkKind::CallArgumentName;
-      nameStr = escapeKeyword(Name.str(), false, stash);
-    } else if (IsLabeledTrailingClosure) {
-      nameKind = ChunkKind::CallArgumentName;
-      nameStr = "_";
-    } else if (!LocalName.empty()) {
-      nameKind = ChunkKind::CallArgumentInternalName;
-      nameStr = escapeKeyword(LocalName.str(), false, stash);
-    }
-    if (!nameStr.empty()) {
-      addChunkWithText(nameKind, nameStr);
-      addChunkWithTextNoCopy(ChunkKind::CallArgumentColon, ": ");
-    }
-  }
-
-  // 'inout' arguments are printed specially.
-  if (IsInOut) {
-    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::Ampersand,
-                           "&");
-    Ty = Ty->getInOutObjectType();
-  }
-
-  // If the parameter is of the type @autoclosure ()->output, then the
-  // code completion should show the parameter of the output type
-  // instead of the function type ()->output.
-  if (IsAutoClosure) {
-    // 'Ty' may be ErrorType.
-    if (auto funcTy = Ty->getAs<FunctionType>())
-      Ty = funcTy->getResult();
-  }
-
-  PrintOptions PO;
-  PO.SkipAttributes = true;
-  PO.PrintOptionalAsImplicitlyUnwrapped = IsIUO;
-  PO.OpaqueReturnTypePrinting =
-      PrintOptions::OpaqueReturnTypePrintingMode::WithoutOpaqueKeyword;
-  if (ContextTy)
-    PO.setBaseType(ContextTy);
-  if (shouldAnnotateResults()) {
-    withNestedGroup(ChunkKind::CallArgumentTypeBegin, [&]() {
-      CodeCompletionStringPrinter printer(*this);
-      auto TL = TypeLoc::withoutLoc(Ty);
-      printer.printTypePre(TL);
-      Ty->print(printer, PO);
-      printer.printTypePost(TL);
-    });
-  } else {
-    std::string TypeName = Ty->getString(PO);
-    addChunkWithText(ChunkKind::CallArgumentType, TypeName);
-  }
-
-  if (HasDefault) {
-    withNestedGroup(ChunkKind::CallArgumentDefaultBegin, []() {
-      // Possibly add the actual value in the future
-    });
-  }
-
-  // Look through optional types and type aliases to find out if we have
-  // function type.
-  Ty = Ty->lookThroughAllOptionalTypes();
-  if (auto AFT = Ty->getAs<AnyFunctionType>()) {
-    // If this is a closure type, add ChunkKind::CallArgumentClosureType or
-    // ChunkKind::CallArgumentClosureExpr for labeled trailing closures.
-    PrintOptions PO;
-    PO.PrintFunctionRepresentationAttrs =
-        PrintOptions::FunctionRepresentationMode::None;
-    PO.SkipAttributes = true;
-    PO.OpaqueReturnTypePrinting =
-        PrintOptions::OpaqueReturnTypePrintingMode::WithoutOpaqueKeyword;
-    PO.AlwaysTryPrintParameterLabels = true;
-    if (ContextTy)
-      PO.setBaseType(ContextTy);
-
-    if (IsLabeledTrailingClosure) {
-      // Expand the closure body.
-      SmallString<32> buffer;
-      llvm::raw_svector_ostream OS(buffer);
-
-      bool firstParam = true;
-      for (const auto &param : AFT->getParams()) {
-        if (!firstParam)
-          OS << ", ";
-        firstParam = false;
-
-        if (param.hasLabel()) {
-          OS << param.getLabel();
-        } else if (param.hasInternalLabel()) {
-          OS << param.getInternalLabel();
-        } else {
-          OS << "<#";
-          if (param.isInOut())
-            OS << "inout ";
-          OS << param.getPlainType()->getString(PO);
-          if (param.isVariadic())
-            OS << "...";
-          OS << "#>";
-        }
-      }
-
-      if (!firstParam)
-        OS << " in";
-
-      addChunkWithText(
-          CodeCompletionString::Chunk::ChunkKind::CallArgumentClosureExpr,
-          OS.str());
-    } else {
-      // Add the closure type.
-      addChunkWithText(
-          CodeCompletionString::Chunk::ChunkKind::CallArgumentClosureType,
-          AFT->getString(PO));
-    }
-  }
-
-  if (IsVarArg)
-    addEllipsis();
-
-  --CurrentNestingLevel;
-}
-
-void CodeCompletionResultBuilder::withNestedGroup(
-    CodeCompletionString::Chunk::ChunkKind Kind,
-    llvm::function_ref<void()> body) {
-  ++CurrentNestingLevel;
-  addSimpleChunk(Kind);
-  body();
-  --CurrentNestingLevel;
-}
-
-void CodeCompletionResultBuilder::addTypeAnnotation(Type T, PrintOptions PO,
-                                                    StringRef suffix) {
-  T = T->getReferenceStorageReferent();
-
-  // Replace '()' with 'Void'.
-  if (T->isVoid())
-    T = T->getASTContext().getVoidDecl()->getDeclaredInterfaceType();
-
-  if (shouldAnnotateResults()) {
-    withNestedGroup(CodeCompletionString::Chunk::ChunkKind::TypeAnnotationBegin,
-                    [&]() {
-                      CodeCompletionStringPrinter printer(*this);
-                      auto TL = TypeLoc::withoutLoc(T);
-                      printer.printTypePre(TL);
-                      T->print(printer, PO);
-                      printer.printTypePost(TL);
-                      if (!suffix.empty())
-                        printer.printText(suffix);
-                    });
-  } else {
-    auto str = T.getString(PO);
-    if (!suffix.empty())
-      str += suffix.str();
-    addTypeAnnotation(str);
-  }
-}
diff --git a/lib/IDE/CodeCompletionResultBuilder.h b/lib/IDE/CodeCompletionResultBuilder.h
index 7e7ac9c1def42..086057c3856b6 100644
--- a/lib/IDE/CodeCompletionResultBuilder.h
+++ b/lib/IDE/CodeCompletionResultBuilder.h
@@ -13,15 +13,11 @@
 #ifndef SWIFT_LIB_IDE_CODE_COMPLETION_RESULT_BUILDER_H
 #define SWIFT_LIB_IDE_CODE_COMPLETION_RESULT_BUILDER_H
 
+#include "CodeCompletionStringBuilder.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/LLVM.h"
-#include "swift/Basic/StringExtras.h"
 #include "swift/IDE/CodeCompletionResult.h"
 #include "swift/IDE/CodeCompletionResultSink.h"
-#include "swift/Parse/Lexer.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/ADT/StringSwitch.h"
 
 namespace clang {
 class Module;
@@ -33,11 +29,7 @@ class ModuleDecl;
 
 namespace ide {
 
-class CodeCompletionStringPrinter;
-
-class CodeCompletionResultBuilder {
-  friend CodeCompletionStringPrinter;
-  
+class CodeCompletionResultBuilder : public CodeCompletionStringBuilder {
   CodeCompletionResultSink &Sink;
   CodeCompletionResultKind Kind;
   SemanticContextKind SemanticContext;
@@ -47,8 +39,6 @@ class CodeCompletionResultBuilder {
   bool HasAsyncAlternative = false;
   std::optional<CodeCompletionLiteralKind> LiteralKind;
   CodeCompletionKeywordKind KeywordKind = CodeCompletionKeywordKind::None;
-  unsigned CurrentNestingLevel = 0;
-  SmallVector<CodeCompletionString::Chunk, 4> Chunks;
   llvm::PointerUnion<const ModuleDecl *, const clang::Module *>
       CurrentModule;
   bool Cancelled = false;
@@ -67,25 +57,6 @@ class CodeCompletionResultBuilder {
   const DeclContext *DC = nullptr;
   bool CanCurrDeclContextHandleAsync = false;
 
-  void addChunkWithText(CodeCompletionString::Chunk::ChunkKind Kind,
-                        StringRef Text);
-
-  void addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind Kind,
-                              StringRef Text) {
-    Chunks.push_back(CodeCompletionString::Chunk::createWithText(
-        Kind, CurrentNestingLevel, Text));
-  }
-
-  void addSimpleChunk(CodeCompletionString::Chunk::ChunkKind Kind) {
-    Chunks.push_back(
-        CodeCompletionString::Chunk::createSimple(Kind,
-                                                  CurrentNestingLevel));
-  }
-
-  CodeCompletionString::Chunk &getLastChunk() {
-    return Chunks.back();
-  }
-
   CodeCompletionResult *takeResult();
   void finishResult();
 
@@ -93,7 +64,8 @@ class CodeCompletionResultBuilder {
   CodeCompletionResultBuilder(CodeCompletionResultSink &Sink,
                               CodeCompletionResultKind Kind,
                               SemanticContextKind SemanticContext)
-      : Sink(Sink), Kind(Kind), SemanticContext(SemanticContext) {}
+      : CodeCompletionStringBuilder(*Sink.Allocator, Sink.annotateResult),
+        Sink(Sink), Kind(Kind), SemanticContext(SemanticContext) {}
 
   ~CodeCompletionResultBuilder() {
     finishResult();
@@ -160,332 +132,6 @@ class CodeCompletionResultBuilder {
     this->CanCurrDeclContextHandleAsync = CanCurrDeclContextHandleAsync;
   }
 
-  void withNestedGroup(CodeCompletionString::Chunk::ChunkKind Kind,
-                  llvm::function_ref<void()> body);
-
-  void addAccessControlKeyword(AccessLevel Access) {
-    switch (Access) {
-    case AccessLevel::Private:
-      addChunkWithTextNoCopy(
-          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
-          "private ");
-      break;
-    case AccessLevel::FilePrivate:
-      addChunkWithTextNoCopy(
-          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
-          "fileprivate ");
-      break;
-    case AccessLevel::Internal:
-      // 'internal' is the default, don't add it.
-      break;
-    case AccessLevel::Package:
-      addChunkWithTextNoCopy(
-          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
-          "package ");
-      break;
-    case AccessLevel::Public:
-      addChunkWithTextNoCopy(
-          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
-          "public ");
-      break;
-    case AccessLevel::Open:
-      addChunkWithTextNoCopy(
-          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
-          "open ");
-      break;
-    }
-  }
-
-  void addRequiredKeyword() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
-        "required ");
-  }
-
-  void addOverrideKeyword() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::OverrideKeyword, "override ");
-  }
-
-  void addDeclIntroducer(StringRef Text) {
-    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::DeclIntroducer,
-                     Text);
-  }
-
-  void addBaseName(StringRef Text) {
-    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::BaseName, Text);
-  }
-
-  void addKeyword(StringRef Text) {
-    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::Keyword, Text);
-  }
-
-  void addTextChunk(StringRef Text) {
-    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::Text, Text);
-  }
-
-  void addAnnotatedTextChunk(StringRef Text) {
-    addTextChunk(Text);
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addAnnotatedThrows() {
-    addThrows();
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addThrows() {
-    addChunkWithTextNoCopy(
-       CodeCompletionString::Chunk::ChunkKind::EffectsSpecifierKeyword,
-       " throws");
-  }
-
-  void addAnnotatedAsync() {
-    addAsync();
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addAsync() {
-    addChunkWithTextNoCopy(
-       CodeCompletionString::Chunk::ChunkKind::EffectsSpecifierKeyword,
-       " async");
-  }
-
-  void addAnnotatedRethrows() {
-    addRethrows();
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addRethrows() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::EffectsSpecifierKeyword,
-        " rethrows");
-  }
-
-  void addAnnotatedLeftParen() {
-    addLeftParen();
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addLeftParen() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::LeftParen, "(");
-  }
-
-  void addAnnotatedRightParen() {
-    addRightParen();
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addRightParen() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::RightParen, ")");
-  }
-
-  void addAnnotatedLeftBracket() {
-    addLeftBracket();
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addLeftBracket() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::LeftBracket, "[");
-  }
-
-  void addAnnotatedRightBracket() {
-    addRightBracket();
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addRightBracket() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::RightBracket, "]");
-  }
-
-  void addLeftAngle() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::LeftAngle, "<");
-  }
-
-  void addRightAngle() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::RightAngle, ">");
-  }
-
-  void addLeadingDot() {
-    addDot();
-  }
-
-  void addDot() {
-    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::Dot, ".");
-  }
-
-  void addEllipsis() {
-    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::Ellipsis,
-                           "...");
-  }
-
-  void addComma() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::Comma, ", ");
-  }
-
-  void addExclamationMark() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::ExclamationMark, "!");
-  }
-
-  void addQuestionMark() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::QuestionMark, "?");
-  }
-
-  void addEqual() {
-    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::Equal, "=");
-  }
-
-  void addDeclAttrParamKeyword(StringRef Name, ArrayRef<StringRef> Parameters,
-                               StringRef Annotation, bool NeedSpecify) {
-    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::
-                     DeclAttrParamKeyword, Name);
-    if (!Parameters.empty()) {
-      addLeftParen();
-      for (auto Parameter : Parameters) {
-        addSimpleNamedParameter(Parameter);
-      }
-      addRightParen();
-    }
-    if (NeedSpecify)
-      addChunkWithText(CodeCompletionString::Chunk::ChunkKind::
-                       DeclAttrParamColon, ": ");
-    if (!Annotation.empty())
-      addTypeAnnotation(Annotation);
-  }
-
-  void addDeclAttrKeyword(StringRef Name, StringRef Annotation) {
-    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::
-                     DeclAttrKeyword, Name);
-    if (!Annotation.empty())
-      addTypeAnnotation(Annotation);
-  }
-
-  void addAttributeKeyword(StringRef Name, StringRef Annotation) {
-    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::Attribute, Name);
-    if (!Annotation.empty())
-      addTypeAnnotation(Annotation);
-  }
-
-  StringRef escapeWithBackticks(StringRef Word,
-                                llvm::SmallString<16> &Escaped) {
-    Escaped.append("`");
-    Escaped.append(Word);
-    Escaped.append("`");
-    return Escaped;
-  }
-
-  StringRef escapeKeyword(StringRef Word, bool escapeAllKeywords,
-                          llvm::SmallString<16> &EscapedKeyword) {
-    EscapedKeyword.clear();
-    bool shouldEscape = false;
-    if (escapeAllKeywords) {
-#define KEYWORD(kw) .Case(#kw, true)
-      shouldEscape = llvm::StringSwitch<bool>(Word)
-#include "swift/AST/TokenKinds.def"
-                         .Default(Lexer::identifierMustAlwaysBeEscaped(Word));
-    } else {
-      shouldEscape = !canBeArgumentLabel(Word) ||
-                     Lexer::identifierMustAlwaysBeEscaped(Word);
-    }
-
-    if (!shouldEscape)
-      return Word;
-
-    return escapeWithBackticks(Word, EscapedKeyword);
-  }
-
-  void addCallParameterColon() {
-    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::
-                     CallArgumentColon, ": ");
-  }
-
-  void addSimpleNamedParameter(StringRef name) {
-    withNestedGroup(CodeCompletionString::Chunk::ChunkKind::CallArgumentBegin, [&] {
-      // Use internal, since we don't want the name to be outside the
-      // placeholder.
-      addChunkWithText(
-          CodeCompletionString::Chunk::ChunkKind::CallArgumentInternalName,
-          name);
-    });
-  }
-
-  void addSimpleTypedParameter(StringRef Annotation, bool IsVarArg = false) {
-    withNestedGroup(CodeCompletionString::Chunk::ChunkKind::CallArgumentBegin, [&] {
-      addChunkWithText(
-          CodeCompletionString::Chunk::ChunkKind::CallArgumentType,
-          Annotation);
-      if (IsVarArg)
-        addEllipsis();
-    });
-  }
-
-  void addCallArgument(Identifier Name, Identifier LocalName, Type Ty,
-                       Type ContextTy, bool IsVarArg, bool IsInOut, bool IsIUO,
-                       bool IsAutoClosure, bool IsLabeledTrailingClosure,
-                       bool IsForOperator, bool HasDefault);
-
-  void addCallArgument(Identifier Name, Type Ty, Type ContextTy = Type(),
-                       bool IsForOperator = false) {
-    addCallArgument(Name, Identifier(), Ty, ContextTy,
-                    /*IsVarArg=*/false, /*IsInOut=*/false, /*IsIUO=*/false,
-                    /*IsAutoClosure=*/false,
-                    /*IsLabeledTrailingClosure=*/false, IsForOperator,
-                    /*HasDefault=*/false);
-  }
-
-  void addGenericParameter(StringRef Name) {
-    withNestedGroup(CodeCompletionString::Chunk::ChunkKind::GenericParameterBegin,
-               [&] {
-      addChunkWithText(
-        CodeCompletionString::Chunk::ChunkKind::GenericParameterName, Name);
-    });
-  }
-
-  void addDynamicLookupMethodCallTail() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::DynamicLookupMethodCallTail,
-        "!");
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addOptionalMethodCallTail() {
-    addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::OptionalMethodCallTail, "?");
-  }
-
-  void addTypeAnnotation(StringRef Type) {
-    addChunkWithText(
-        CodeCompletionString::Chunk::ChunkKind::TypeAnnotation, Type);
-    getLastChunk().setIsAnnotation();
-  }
-
-  void addTypeAnnotation(Type T, PrintOptions PO, StringRef suffix = "");
-
-  void addBraceStmtWithCursor(StringRef Description = "") {
-    addChunkWithText(
-        CodeCompletionString::Chunk::ChunkKind::BraceStmtWithCursor,
-        Description);
-  }
-
-  void addWhitespace(StringRef space) {
-    addChunkWithText(
-        CodeCompletionString::Chunk::ChunkKind::Whitespace, space);
-  }
-
-  void addAnnotatedWhitespace(StringRef space) {
-    addWhitespace(space);
-    getLastChunk().setIsAnnotation();
-  }
-
   void setBriefDocComment(StringRef comment) {
     BriefDocComment = comment;
   }
diff --git a/lib/IDE/CodeCompletionResultType.cpp b/lib/IDE/CodeCompletionResultType.cpp
index 5f2defd13c329..1cca1fa8d8fcc 100644
--- a/lib/IDE/CodeCompletionResultType.cpp
+++ b/lib/IDE/CodeCompletionResultType.cpp
@@ -466,7 +466,7 @@ bool CodeCompletionResultType::isBackedByUSRs() const {
   return llvm::all_of(
       getResultTypes(),
       [](const PointerUnion<Type, const USRBasedType *> &ResultType) {
-        return ResultType.is<const USRBasedType *>();
+        return isa<const USRBasedType *>(ResultType);
       });
 }
 
@@ -481,7 +481,7 @@ CodeCompletionResultType::getUSRBasedResultTypes(
       USRBasedTypes.push_back(USRType);
     } else {
       USRBasedTypes.push_back(
-          USRBasedType::fromType(ResultType.get<Type>(), Arena));
+          USRBasedType::fromType(cast<Type>(ResultType), Arena));
     }
   }
   return USRBasedTypes;
@@ -514,7 +514,7 @@ TypeRelation CodeCompletionResultType::calculateTypeRelation(
       Res = std::max(Res, USRTypeContext->typeRelation(USRType));
     } else {
       Res = std::max(
-          Res, calculateMaxTypeRelation(Ty.get<Type>(), *TypeContext, *DC));
+          Res, calculateMaxTypeRelation(cast<Type>(Ty), *TypeContext, *DC));
     }
   }
   return Res;
diff --git a/lib/IDE/CodeCompletionString.cpp b/lib/IDE/CodeCompletionString.cpp
index cc7d57bcc6108..6479b3a1e87df 100644
--- a/lib/IDE/CodeCompletionString.cpp
+++ b/lib/IDE/CodeCompletionString.cpp
@@ -18,8 +18,7 @@ using namespace swift;
 using namespace swift::ide;
 
 CodeCompletionString::CodeCompletionString(ArrayRef<Chunk> Chunks) {
-  std::uninitialized_copy(Chunks.begin(), Chunks.end(),
-                          getTrailingObjects<Chunk>());
+  std::uninitialized_copy(Chunks.begin(), Chunks.end(), getTrailingObjects());
   NumChunks = Chunks.size();
 }
 
diff --git a/lib/IDE/CodeCompletionStringBuilder.cpp b/lib/IDE/CodeCompletionStringBuilder.cpp
new file mode 100644
index 0000000000000..213dcdfed9a72
--- /dev/null
+++ b/lib/IDE/CodeCompletionStringBuilder.cpp
@@ -0,0 +1,587 @@
+//===--- CodeCompletionStringBuilder.cpp --------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeCompletionStringBuilder.h"
+#include "swift/AST/ASTContext.h"
+#include "swift/AST/Decl.h"
+#include "swift/AST/GenericEnvironment.h"
+#include "swift/AST/ParameterList.h"
+#include "swift/AST/PrintOptions.h"
+#include "swift/AST/Types.h"
+#include "swift/Basic/StringExtras.h"
+#include "swift/IDE/CodeCompletionStringPrinter.h"
+#include "swift/Parse/Lexer.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace swift;
+using namespace swift::ide;
+
+Type ide::eraseArchetypes(Type type, GenericSignature genericSig) {
+  if (auto *genericFuncType = type->getAs<GenericFunctionType>()) {
+    assert(genericFuncType->getGenericSignature()->isEqual(genericSig) &&
+           "if not, just use the GFT's signature instead below");
+
+    SmallVector<AnyFunctionType::Param, 8> erasedParams;
+    for (const auto &param : genericFuncType->getParams()) {
+      auto erasedTy = eraseArchetypes(param.getPlainType(), genericSig);
+      erasedParams.emplace_back(param.withType(erasedTy));
+    }
+    return GenericFunctionType::get(
+        genericSig, erasedParams,
+        eraseArchetypes(genericFuncType->getResult(), genericSig),
+        genericFuncType->getExtInfo());
+  }
+
+  return type.transformRec([&](Type t) -> std::optional<Type> {
+    // FIXME: Code completion should only deal with one or the other,
+    // and not both.
+    if (auto *archetypeType = t->getAs<ArchetypeType>()) {
+      // Don't erase opaque archetype.
+      if (isa<OpaqueTypeArchetypeType>(archetypeType) &&
+          archetypeType->isRoot())
+        return std::nullopt;
+
+      auto genericSig =
+          archetypeType->getGenericEnvironment()->getGenericSignature();
+      auto upperBound =
+          genericSig->getUpperBound(archetypeType->getInterfaceType(),
+                                    /*forExistentialSelf=*/false,
+                                    /*withParameterizedProtocols=*/false);
+
+      if (!upperBound->isAny())
+        return upperBound;
+    }
+
+    if (t->isTypeParameter() && genericSig) {
+      auto upperBound =
+          genericSig->getUpperBound(t,
+                                    /*forExistentialSelf=*/false,
+                                    /*withParameterizedProtocols=*/false);
+
+      if (!upperBound->isAny())
+        return upperBound;
+    }
+
+    return std::nullopt;
+  });
+}
+
+/// Return whether \p param has a non-desirable default value for code
+/// completion.
+///
+/// 'ClangImporter::Implementation::inferDefaultArgument()' automatically adds
+/// default values for some parameters;
+///   * NS_OPTIONS enum type with the name '...Options'.
+///   * NSDictionary and labeled 'options', 'attributes', or 'userInfo'.
+///
+/// But sometimes, this behavior isn't really desirable. This function add a
+/// heuristic where if a parameter matches all the following condition, we
+/// consider the imported default value is _not_ desirable:
+///   * it is the first parameter,
+///   * it doesn't have an argument label, and
+///   * the imported function base name ends with those words
+/// For example, ClangImporter imports:
+///
+///   -(void)addAttributes:(NSDictionary *)attrs, options:(NSDictionary *)opts;
+///
+/// as:
+///
+///   func addAttributes(_ attrs: [AnyHashable:Any] = [:],
+///                      options opts: [AnyHashable:Any] = [:])
+///
+/// In this case, we don't want 'attrs' defaulted because the function name have
+/// 'Attribute' in its name so calling 'value.addAttribute()' doesn't make
+/// sense, but we _do_ want to keep 'opts' defaulted.
+///
+/// Note that:
+///
+///   -(void)performWithOptions:(NSDictionary *) opts;
+///
+/// This doesn't match the condition because the base name of the function in
+/// Swift is 'peform':
+///
+///   func perform(options opts: [AnyHashable:Any] = [:])
+///
+static bool isNonDesirableImportedDefaultArg(const ParamDecl *param) {
+  auto kind = param->getDefaultArgumentKind();
+  if (kind != DefaultArgumentKind::EmptyArray &&
+      kind != DefaultArgumentKind::EmptyDictionary)
+    return false;
+
+  if (!param->getArgumentName().empty())
+    return false;
+
+  auto *func = dyn_cast<FuncDecl>(param->getDeclContext());
+  if (!func->hasClangNode())
+    return false;
+  if (func->getParameters()->front() != param)
+    return false;
+  if (func->getBaseName().isSpecial())
+    return false;
+
+  auto baseName = func->getBaseName().getIdentifier().str();
+  switch (kind) {
+  case DefaultArgumentKind::EmptyArray:
+    return (baseName.ends_with("Options"));
+  case DefaultArgumentKind::EmptyDictionary:
+    return (baseName.ends_with("Options") || baseName.ends_with("Attributes") ||
+            baseName.ends_with("UserInfo"));
+  default:
+    llvm_unreachable("unhandled DefaultArgumentKind");
+  }
+}
+
+bool swift::ide::hasInterestingDefaultValue(const ParamDecl *param) {
+  if (!param)
+    return false;
+
+  switch (param->getDefaultArgumentKind()) {
+  case DefaultArgumentKind::Normal:
+  case DefaultArgumentKind::NilLiteral:
+  case DefaultArgumentKind::StoredProperty:
+  case DefaultArgumentKind::Inherited:
+    return true;
+
+  case DefaultArgumentKind::EmptyArray:
+  case DefaultArgumentKind::EmptyDictionary:
+    if (isNonDesirableImportedDefaultArg(param))
+      return false;
+    return true;
+
+  case DefaultArgumentKind::None:
+#define MAGIC_IDENTIFIER(NAME, STRING) case DefaultArgumentKind::NAME:
+#include "swift/AST/MagicIdentifierKinds.def"
+  case DefaultArgumentKind::ExpressionMacro:
+    return false;
+  }
+}
+
+void CodeCompletionStringBuilder::addChunkWithText(
+    CodeCompletionString::Chunk::ChunkKind Kind, StringRef Text) {
+  addChunkWithTextNoCopy(Kind, Text.copy(Allocator));
+}
+
+StringRef CodeCompletionStringBuilder::escapeKeyword(
+    StringRef Word, bool escapeAllKeywords,
+    llvm::SmallString<16> &EscapedKeyword) {
+  EscapedKeyword.clear();
+  bool shouldEscape = false;
+  if (escapeAllKeywords) {
+#define KEYWORD(kw) .Case(#kw, true)
+    shouldEscape = llvm::StringSwitch<bool>(Word)
+#include "swift/AST/TokenKinds.def"
+                       .Default(Lexer::identifierMustAlwaysBeEscaped(Word));
+  } else {
+    shouldEscape =
+        !canBeArgumentLabel(Word) || Lexer::identifierMustAlwaysBeEscaped(Word);
+  }
+
+  if (!shouldEscape)
+    return Word;
+
+  return escapeWithBackticks(Word, EscapedKeyword);
+}
+
+void CodeCompletionStringBuilder::withNestedGroup(
+    CodeCompletionString::Chunk::ChunkKind Kind,
+    llvm::function_ref<void()> body) {
+  ++CurrentNestingLevel;
+  addSimpleChunk(Kind);
+  body();
+  --CurrentNestingLevel;
+}
+
+void CodeCompletionStringBuilder::addCallArgument(
+    Identifier Name, Identifier LocalName, Type Ty, Type ContextTy,
+    bool IsVarArg, bool IsInOut, bool IsIUO, bool IsAutoClosure,
+    bool IsLabeledTrailingClosure, bool IsForOperator, bool HasDefault,
+    StringRef DefaultValue) {
+  ++CurrentNestingLevel;
+  using ChunkKind = CodeCompletionString::Chunk::ChunkKind;
+
+  addSimpleChunk(ChunkKind::CallArgumentBegin);
+
+  if (AnnotateResults) {
+    llvm::SmallString<16> EscapedKeyword;
+    if (!Name.empty()) {
+      addChunkWithText(ChunkKind::CallArgumentName,
+                       escapeKeyword(Name.str(), false, EscapedKeyword));
+      if (!LocalName.empty() && Name != LocalName) {
+        addChunkWithTextNoCopy(ChunkKind::Text, " ");
+        getLastChunk().setIsAnnotation();
+        addChunkWithText(ChunkKind::CallArgumentInternalName,
+                         escapeKeyword(LocalName.str(), false, EscapedKeyword));
+        getLastChunk().setIsAnnotation();
+      }
+      addChunkWithTextNoCopy(ChunkKind::CallArgumentColon, ": ");
+    } else if (!LocalName.empty()) {
+      addChunkWithTextNoCopy(ChunkKind::CallArgumentName, "_");
+      getLastChunk().setIsAnnotation();
+      addChunkWithTextNoCopy(ChunkKind::Text, " ");
+      getLastChunk().setIsAnnotation();
+      addChunkWithText(ChunkKind::CallArgumentInternalName,
+                       escapeKeyword(LocalName.str(), false, EscapedKeyword));
+      addChunkWithTextNoCopy(ChunkKind::CallArgumentColon, ": ");
+    } else if (!IsForOperator) {
+      addChunkWithTextNoCopy(ChunkKind::CallArgumentName, "_");
+      if (!IsLabeledTrailingClosure)
+        getLastChunk().setIsAnnotation();
+      addChunkWithTextNoCopy(ChunkKind::CallArgumentColon, ": ");
+      if (!IsLabeledTrailingClosure)
+        getLastChunk().setIsAnnotation();
+    }
+  } else {
+    llvm::SmallString<16> stash;
+    ChunkKind nameKind;
+    StringRef nameStr;
+    if (!Name.empty()) {
+      nameKind = ChunkKind::CallArgumentName;
+      nameStr = escapeKeyword(Name.str(), false, stash);
+    } else if (IsLabeledTrailingClosure) {
+      nameKind = ChunkKind::CallArgumentName;
+      nameStr = "_";
+    } else if (!LocalName.empty()) {
+      nameKind = ChunkKind::CallArgumentInternalName;
+      nameStr = escapeKeyword(LocalName.str(), false, stash);
+    }
+    if (!nameStr.empty()) {
+      if (UnderscoreEmptyArgumentLabel &&
+          nameKind == ChunkKind::CallArgumentInternalName) {
+        addChunkWithTextNoCopy(ChunkKind::CallArgumentName, "_");
+        addChunkWithTextNoCopy(ChunkKind::Text, " ");
+      }
+
+      addChunkWithText(nameKind, nameStr);
+      addChunkWithTextNoCopy(ChunkKind::CallArgumentColon, ": ");
+    }
+  }
+
+  // 'inout' arguments are printed specially.
+  if (IsInOut) {
+    if (FullParameterFlags) {
+      addChunkWithTextNoCopy(ChunkKind::Keyword, "inout");
+      addChunkWithTextNoCopy(ChunkKind::Text, " ");
+    } else {
+      addChunkWithTextNoCopy(ChunkKind::Ampersand, "&");
+    }
+    Ty = Ty->getInOutObjectType();
+  }
+
+  // If the parameter is of the type @autoclosure ()->output, then the
+  // code completion should show the parameter of the output type
+  // instead of the function type ()->output.
+  if (IsAutoClosure) {
+    // 'Ty' may be ErrorType.
+    if (auto funcTy = Ty->getAs<FunctionType>())
+      Ty = funcTy->getResult();
+  }
+
+  NonRecursivePrintOptions nrOptions;
+  if (IsIUO)
+    nrOptions |= NonRecursivePrintOption::ImplicitlyUnwrappedOptional;
+
+  PrintOptions PO;
+  PO.SkipAttributes = true;
+  PO.OpaqueReturnTypePrinting =
+      PrintOptions::OpaqueReturnTypePrintingMode::WithoutOpaqueKeyword;
+  if (ContextTy)
+    PO.setBaseType(ContextTy);
+  if (AnnotateResults) {
+    withNestedGroup(ChunkKind::CallArgumentTypeBegin, [&]() {
+      CodeCompletionStringPrinter printer(*this);
+      auto TL = TypeLoc::withoutLoc(Ty);
+      printer.printTypePre(TL);
+      Ty->print(printer, PO, nrOptions);
+      printer.printTypePost(TL);
+    });
+  } else {
+    std::string TypeName = Ty->getString(PO, nrOptions);
+    addChunkWithText(ChunkKind::CallArgumentType, TypeName);
+  }
+
+  if (HasDefault) {
+    withNestedGroup(ChunkKind::CallArgumentDefaultBegin, [&]() {
+      if (DefaultValue.empty())
+        return;
+
+      addWhitespace(" ");
+      addEqual();
+      addWhitespace(" ");
+      addChunkWithText(ChunkKind::Text, DefaultValue);
+    });
+  }
+
+  // Look through optional types and type aliases to find out if we have
+  // function type.
+  Ty = Ty->lookThroughAllOptionalTypes();
+  if (auto AFT = Ty->getAs<AnyFunctionType>()) {
+    // If this is a closure type, add ChunkKind::CallArgumentClosureType or
+    // ChunkKind::CallArgumentClosureExpr for labeled trailing closures.
+    PrintOptions PO;
+    PO.PrintFunctionRepresentationAttrs =
+        PrintOptions::FunctionRepresentationMode::None;
+    PO.SkipAttributes = true;
+    PO.OpaqueReturnTypePrinting =
+        PrintOptions::OpaqueReturnTypePrintingMode::WithoutOpaqueKeyword;
+    PO.AlwaysTryPrintParameterLabels = true;
+    if (ContextTy)
+      PO.setBaseType(ContextTy);
+
+    if (IsLabeledTrailingClosure) {
+      // Expand the closure body.
+      SmallString<32> buffer;
+      llvm::raw_svector_ostream OS(buffer);
+
+      bool firstParam = true;
+      for (const auto &param : AFT->getParams()) {
+        if (!firstParam)
+          OS << ", ";
+        firstParam = false;
+
+        if (param.hasLabel()) {
+          OS << param.getLabel();
+        } else if (param.hasInternalLabel()) {
+          OS << param.getInternalLabel();
+        } else {
+          OS << "<#";
+          if (param.isInOut())
+            OS << "inout ";
+          OS << param.getPlainType()->getString(PO);
+          if (param.isVariadic())
+            OS << "...";
+          OS << "#>";
+        }
+      }
+
+      if (!firstParam)
+        OS << " in";
+
+      addChunkWithText(
+          CodeCompletionString::Chunk::ChunkKind::CallArgumentClosureExpr,
+          OS.str());
+    } else {
+      // Add the closure type.
+      addChunkWithText(
+          CodeCompletionString::Chunk::ChunkKind::CallArgumentClosureType,
+          AFT->getString(PO));
+    }
+  }
+
+  if (IsVarArg)
+    addEllipsis();
+
+  --CurrentNestingLevel;
+}
+
+void CodeCompletionStringBuilder::addTypeAnnotation(
+    Type T, const PrintOptions &PO, NonRecursivePrintOptions nrOptions,
+    StringRef suffix) {
+  T = T->getReferenceStorageReferent();
+
+  // Replace '()' with 'Void'.
+  if (T->isVoid())
+    T = T->getASTContext().getVoidDecl()->getDeclaredInterfaceType();
+
+  if (AnnotateResults) {
+    withNestedGroup(CodeCompletionString::Chunk::ChunkKind::TypeAnnotationBegin,
+                    [&]() {
+                      CodeCompletionStringPrinter printer(*this);
+                      auto TL = TypeLoc::withoutLoc(T);
+                      printer.printTypePre(TL);
+                      T->print(printer, PO, nrOptions);
+                      printer.printTypePost(TL);
+                      if (!suffix.empty())
+                        printer.printText(suffix);
+                    });
+  } else {
+    auto str = T.getString(PO, nrOptions);
+    if (!suffix.empty())
+      str += suffix.str();
+    addTypeAnnotation(str);
+  }
+}
+
+void CodeCompletionStringBuilder::addValueBaseName(DeclBaseName Name,
+                                                   bool IsMember) {
+  auto NameStr = Name.userFacingName();
+  if (Name.mustAlwaysBeEscaped()) {
+    // Names that are raw identifiers must always be escaped regardless of
+    // their position.
+    SmallString<16> buffer;
+    addBaseName(escapeWithBackticks(NameStr, buffer));
+    return;
+  }
+
+  bool shouldEscapeKeywords;
+  if (Name.isSpecial()) {
+    // Special names (i.e. 'init') are always displayed as its user facing
+    // name.
+    shouldEscapeKeywords = false;
+  } else if (IsMember) {
+    // After dot. User can write any keyword after '.' except for `init` and
+    // `self`. E.g. 'func `init`()' must be called by 'expr.`init`()'.
+    shouldEscapeKeywords = NameStr == "self" || NameStr == "init";
+  } else {
+    // As primary expresson. We have to escape almost every keywords except
+    // for 'self' and 'Self'.
+    shouldEscapeKeywords = NameStr != "self" && NameStr != "Self";
+  }
+
+  if (!shouldEscapeKeywords) {
+    addBaseName(NameStr);
+  } else {
+    SmallString<16> buffer;
+    addBaseName(escapeKeyword(NameStr, true, buffer));
+  }
+}
+
+bool CodeCompletionStringBuilder::addCallArgumentPatterns(
+    ArrayRef<AnyFunctionType::Param> typeParams,
+    ArrayRef<const ParamDecl *> declParams, const DeclContext *DC,
+    GenericSignature genericSig, DefaultArgumentOutputMode defaultArgsMode,
+    bool includeDefaultValues) {
+  assert(declParams.empty() || typeParams.size() == declParams.size());
+
+  bool modifiedBuilder = false;
+  bool needComma = false;
+  // Iterate over each parameter.
+  for (unsigned i = 0; i != typeParams.size(); ++i) {
+    auto &typeParam = typeParams[i];
+
+    Identifier argName = typeParam.getLabel();
+    Identifier bodyName;
+    bool isIUO = false;
+    bool hasDefault = false;
+
+    // Scratch for getting default value string representation
+    SmallString<32> Scratch;
+    StringRef defaultValue;
+
+    if (!declParams.empty()) {
+      const ParamDecl *PD = declParams[i];
+      hasDefault =
+          PD->isDefaultArgument() && !isNonDesirableImportedDefaultArg(PD);
+
+      if (hasDefault) {
+        // Skip default arguments if we're either not including them or they
+        // aren't interesting
+        bool skipDefaultArgument;
+        switch (defaultArgsMode) {
+        case DefaultArgumentOutputMode::None:
+          skipDefaultArgument = true;
+          break;
+        case DefaultArgumentOutputMode::Interesting:
+          skipDefaultArgument = !hasInterestingDefaultValue(PD);
+          break;
+        case DefaultArgumentOutputMode::All:
+          skipDefaultArgument = false;
+          break;
+        }
+
+        if (skipDefaultArgument)
+          continue;
+      }
+
+      argName = PD->getArgumentName();
+      bodyName = PD->getParameterName();
+      isIUO = PD->isImplicitlyUnwrappedOptional();
+
+      if (hasDefault && includeDefaultValues)
+        defaultValue = PD->getDefaultValueStringRepresentation(Scratch);
+    }
+
+    bool isVariadic = typeParam.isVariadic();
+    bool isInOut = typeParam.isInOut();
+    bool isAutoclosure = typeParam.isAutoClosure();
+    Type paramTy = typeParam.getPlainType();
+    if (isVariadic)
+      paramTy = ParamDecl::getVarargBaseTy(paramTy);
+
+    Type contextTy;
+    if (auto typeContext = DC->getInnermostTypeContext())
+      contextTy = typeContext->getDeclaredTypeInContext();
+
+    if (needComma)
+      addComma();
+    addCallArgument(argName, bodyName, eraseArchetypes(paramTy, genericSig),
+                    contextTy, isVariadic, isInOut, isIUO, isAutoclosure,
+                    /*IsLabeledTrailingClosure=*/false,
+                    /*IsForOperator=*/false, hasDefault, defaultValue);
+
+    modifiedBuilder = true;
+    needComma = true;
+  }
+
+  return modifiedBuilder;
+}
+
+bool CodeCompletionStringBuilder::addCallArgumentPatterns(
+    const AnyFunctionType *AFT, const ParameterList *Params,
+    const DeclContext *DC, GenericSignature genericSig,
+    DefaultArgumentOutputMode defaultArgsMode, bool includeDefaultValues) {
+  ArrayRef<const ParamDecl *> declParams;
+  if (Params)
+    declParams = Params->getArray();
+  return addCallArgumentPatterns(AFT->getParams(), declParams, DC, genericSig,
+                                 defaultArgsMode, includeDefaultValues);
+}
+
+void CodeCompletionStringBuilder::addTypeAnnotation(
+    Type T, const DeclContext *DC, GenericSignature genericSig) {
+  PrintOptions PO;
+  PO.OpaqueReturnTypePrinting =
+      PrintOptions::OpaqueReturnTypePrintingMode::WithoutOpaqueKeyword;
+  if (auto typeContext = DC->getInnermostTypeContext())
+    PO.setBaseType(typeContext->getDeclaredTypeInContext());
+  addTypeAnnotation(eraseArchetypes(T, genericSig), PO);
+}
+
+void CodeCompletionStringBuilder::
+    addTypeAnnotationForImplicitlyUnwrappedOptional(Type T,
+                                                    const DeclContext *DC,
+                                                    GenericSignature genericSig,
+                                                    bool dynamicOrOptional) {
+  std::string suffix;
+  // FIXME: This retains previous behavior, but in reality the type of dynamic
+  // lookups is IUO, not Optional as it is for the @optional attribute.
+  if (dynamicOrOptional) {
+    T = T->getOptionalObjectType();
+    suffix = "?";
+  }
+
+  NonRecursivePrintOptions nrOptions =
+      NonRecursivePrintOption::ImplicitlyUnwrappedOptional;
+
+  PrintOptions PO;
+  PO.OpaqueReturnTypePrinting =
+      PrintOptions::OpaqueReturnTypePrintingMode::WithoutOpaqueKeyword;
+  if (auto typeContext = DC->getInnermostTypeContext())
+    PO.setBaseType(typeContext->getDeclaredTypeInContext());
+  addTypeAnnotation(eraseArchetypes(T, genericSig), PO, nrOptions, suffix);
+}
+
+void CodeCompletionStringBuilder::addEffectsSpecifiers(
+    const AnyFunctionType *AFT, const AbstractFunctionDecl *AFD,
+    bool forceAsync) {
+  assert(AFT != nullptr);
+
+  // 'async'.
+  if (forceAsync || (AFD && AFD->hasAsync()) ||
+      (AFT->hasExtInfo() && AFT->isAsync()))
+    addAnnotatedAsync();
+
+  // 'throws' or 'rethrows'.
+  if (AFD && AFD->getAttrs().hasAttribute<RethrowsAttr>())
+    addAnnotatedRethrows();
+  else if (AFT->hasExtInfo() && AFT->isThrowing())
+    addAnnotatedThrows();
+}
diff --git a/lib/IDE/CodeCompletionStringBuilder.h b/lib/IDE/CodeCompletionStringBuilder.h
new file mode 100644
index 0000000000000..409ea144a54c1
--- /dev/null
+++ b/lib/IDE/CodeCompletionStringBuilder.h
@@ -0,0 +1,441 @@
+//===--- CodeCompletionStringBuilder.h ----------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_IDE_CODECOMPLETIONSTRINGBUILDER_H
+#define SWIFT_IDE_CODECOMPLETIONSTRINGBUILDER_H
+
+#include "swift/AST/Types.h"
+#include "swift/IDE/CodeCompletionString.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/Allocator.h"
+
+namespace swift {
+namespace ide {
+
+class CodeCompletionStringPrinter;
+
+/// For printing in code completion strings, replace archetypes with
+/// protocol compositions.
+///
+/// FIXME: Perhaps this should be an option in PrintOptions instead.
+Type eraseArchetypes(Type type, GenericSignature genericSig);
+
+bool hasInterestingDefaultValue(const ParamDecl *param);
+
+/// Modes for printing arguments with default values in
+/// \c CodeCompletionStringBuilder::addCallArgumentPatterns
+enum class DefaultArgumentOutputMode {
+  /// Don't output any argument that has a default value.
+  None,
+  /// Output arguments with interesting default values only.
+  /// \sa hasInterestingDefaultValue
+  Interesting,
+  /// Output all arguments with default values (even non-interesting ones).
+  All
+};
+
+class CodeCompletionStringBuilder {
+  friend CodeCompletionStringPrinter;
+
+  llvm::BumpPtrAllocator &Allocator;
+  unsigned CurrentNestingLevel = 0;
+  SmallVector<CodeCompletionString::Chunk, 4> Chunks;
+
+  bool AnnotateResults;
+  bool UnderscoreEmptyArgumentLabel;
+  bool FullParameterFlags;
+
+public:
+  CodeCompletionStringBuilder(llvm::BumpPtrAllocator &Allocator,
+                              bool AnnotateResults = false,
+                              bool UnderscoreEmptyArgumentLabel = false,
+                              bool FullParameterFlags = false)
+      : Allocator(Allocator), AnnotateResults(AnnotateResults),
+        UnderscoreEmptyArgumentLabel(UnderscoreEmptyArgumentLabel),
+        FullParameterFlags(FullParameterFlags) {}
+
+private:
+  void addChunkWithText(CodeCompletionString::Chunk::ChunkKind Kind,
+                        StringRef Text);
+
+  void addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind Kind,
+                              StringRef Text) {
+    Chunks.push_back(CodeCompletionString::Chunk::createWithText(
+        Kind, CurrentNestingLevel, Text));
+  }
+
+  void addSimpleChunk(CodeCompletionString::Chunk::ChunkKind Kind) {
+    Chunks.push_back(
+        CodeCompletionString::Chunk::createSimple(Kind, CurrentNestingLevel));
+  }
+
+  CodeCompletionString::Chunk &getLastChunk() { return Chunks.back(); }
+
+public:
+  void withNestedGroup(CodeCompletionString::Chunk::ChunkKind Kind,
+                       llvm::function_ref<void()> body);
+
+  void addAccessControlKeyword(AccessLevel Access) {
+    switch (Access) {
+    case AccessLevel::Private:
+      addChunkWithTextNoCopy(
+          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
+          "private ");
+      break;
+    case AccessLevel::FilePrivate:
+      addChunkWithTextNoCopy(
+          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
+          "fileprivate ");
+      break;
+    case AccessLevel::Internal:
+      // 'internal' is the default, don't add it.
+      break;
+    case AccessLevel::Package:
+      addChunkWithTextNoCopy(
+          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
+          "package ");
+      break;
+    case AccessLevel::Public:
+      addChunkWithTextNoCopy(
+          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
+          "public ");
+      break;
+    case AccessLevel::Open:
+      addChunkWithTextNoCopy(
+          CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
+          "open ");
+      break;
+    }
+  }
+
+  void addRequiredKeyword() {
+    addChunkWithTextNoCopy(
+        CodeCompletionString::Chunk::ChunkKind::AccessControlKeyword,
+        "required ");
+  }
+
+  void addOverrideKeyword() {
+    addChunkWithTextNoCopy(
+        CodeCompletionString::Chunk::ChunkKind::OverrideKeyword, "override ");
+  }
+
+  void addDeclIntroducer(StringRef Text) {
+    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::DeclIntroducer,
+                     Text);
+  }
+
+  void addBaseName(StringRef Text) {
+    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::BaseName, Text);
+  }
+
+  void addKeyword(StringRef Text) {
+    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::Keyword, Text);
+  }
+
+  void addTextChunk(StringRef Text) {
+    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::Text, Text);
+  }
+
+  void addAnnotatedTextChunk(StringRef Text) {
+    addTextChunk(Text);
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addAnnotatedThrows() {
+    addThrows();
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addThrows() {
+    addChunkWithTextNoCopy(
+        CodeCompletionString::Chunk::ChunkKind::EffectsSpecifierKeyword,
+        " throws");
+  }
+
+  void addAnnotatedAsync() {
+    addAsync();
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addAsync() {
+    addChunkWithTextNoCopy(
+        CodeCompletionString::Chunk::ChunkKind::EffectsSpecifierKeyword,
+        " async");
+  }
+
+  void addAnnotatedRethrows() {
+    addRethrows();
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addRethrows() {
+    addChunkWithTextNoCopy(
+        CodeCompletionString::Chunk::ChunkKind::EffectsSpecifierKeyword,
+        " rethrows");
+  }
+
+  void addAnnotatedLeftParen() {
+    addLeftParen();
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addLeftParen() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::LeftParen,
+                           "(");
+  }
+
+  void addAnnotatedRightParen() {
+    addRightParen();
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addRightParen() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::RightParen,
+                           ")");
+  }
+
+  void addAnnotatedLeftBracket() {
+    addLeftBracket();
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addLeftBracket() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::LeftBracket,
+                           "[");
+  }
+
+  void addAnnotatedRightBracket() {
+    addRightBracket();
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addRightBracket() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::RightBracket,
+                           "]");
+  }
+
+  void addLeftAngle() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::LeftAngle,
+                           "<");
+  }
+
+  void addRightAngle() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::RightAngle,
+                           ">");
+  }
+
+  void addLeadingDot() { addDot(); }
+
+  void addDot() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::Dot, ".");
+  }
+
+  void addEllipsis() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::Ellipsis,
+                           "...");
+  }
+
+  void addComma() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::Comma, ", ");
+  }
+
+  void addExclamationMark() {
+    addChunkWithTextNoCopy(
+        CodeCompletionString::Chunk::ChunkKind::ExclamationMark, "!");
+  }
+
+  void addQuestionMark() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::QuestionMark,
+                           "?");
+  }
+
+  void addEqual() {
+    addChunkWithTextNoCopy(CodeCompletionString::Chunk::ChunkKind::Equal, "=");
+  }
+
+  void addDeclAttrParamKeyword(StringRef Name, ArrayRef<StringRef> Parameters,
+                               StringRef Annotation, bool NeedSpecify) {
+    addChunkWithText(
+        CodeCompletionString::Chunk::ChunkKind::DeclAttrParamKeyword, Name);
+    if (!Parameters.empty()) {
+      addLeftParen();
+      for (auto Parameter : Parameters) {
+        addSimpleNamedParameter(Parameter);
+      }
+      addRightParen();
+    }
+    if (NeedSpecify)
+      addChunkWithText(
+          CodeCompletionString::Chunk::ChunkKind::DeclAttrParamColon, ": ");
+    if (!Annotation.empty())
+      addTypeAnnotation(Annotation);
+  }
+
+  void addDeclAttrKeyword(StringRef Name, StringRef Annotation) {
+    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::DeclAttrKeyword,
+                     Name);
+    if (!Annotation.empty())
+      addTypeAnnotation(Annotation);
+  }
+
+  void addAttributeKeyword(StringRef Name, StringRef Annotation) {
+    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::Attribute, Name);
+    if (!Annotation.empty())
+      addTypeAnnotation(Annotation);
+  }
+
+  StringRef escapeWithBackticks(StringRef Word,
+                                llvm::SmallString<16> &Escaped) {
+    Escaped.append("`");
+    Escaped.append(Word);
+    Escaped.append("`");
+    return Escaped;
+  }
+
+  StringRef escapeKeyword(StringRef Word, bool escapeAllKeywords,
+                          llvm::SmallString<16> &EscapedKeyword);
+
+  void addCallParameterColon() {
+    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::CallArgumentColon,
+                     ": ");
+  }
+
+  void addSimpleNamedParameter(StringRef name) {
+    withNestedGroup(
+        CodeCompletionString::Chunk::ChunkKind::CallArgumentBegin, [&] {
+          // Use internal, since we don't want the name to be outside the
+          // placeholder.
+          addChunkWithText(
+              CodeCompletionString::Chunk::ChunkKind::CallArgumentInternalName,
+              name);
+        });
+  }
+
+  void addSimpleTypedParameter(StringRef Annotation, bool IsVarArg = false) {
+    withNestedGroup(
+        CodeCompletionString::Chunk::ChunkKind::CallArgumentBegin, [&] {
+          addChunkWithText(
+              CodeCompletionString::Chunk::ChunkKind::CallArgumentType,
+              Annotation);
+          if (IsVarArg)
+            addEllipsis();
+        });
+  }
+
+  void addCallArgument(Identifier Name, Identifier LocalName, Type Ty,
+                       Type ContextTy, bool IsVarArg, bool IsInOut, bool IsIUO,
+                       bool IsAutoClosure, bool IsLabeledTrailingClosure,
+                       bool IsForOperator, bool HasDefault,
+                       StringRef DefaultValue = {});
+
+  void addCallArgument(Identifier Name, Type Ty, Type ContextTy = Type(),
+                       bool IsForOperator = false) {
+    addCallArgument(Name, Identifier(), Ty, ContextTy,
+                    /*IsVarArg=*/false, /*IsInOut=*/false, /*IsIUO=*/false,
+                    /*IsAutoClosure=*/false,
+                    /*IsLabeledTrailingClosure=*/false, IsForOperator,
+                    /*HasDefault=*/false);
+  }
+
+  void addGenericParameter(StringRef Name) {
+    withNestedGroup(
+        CodeCompletionString::Chunk::ChunkKind::GenericParameterBegin, [&] {
+          addChunkWithText(
+              CodeCompletionString::Chunk::ChunkKind::GenericParameterName,
+              Name);
+        });
+  }
+
+  void addDynamicLookupMethodCallTail() {
+    addChunkWithTextNoCopy(
+        CodeCompletionString::Chunk::ChunkKind::DynamicLookupMethodCallTail,
+        "!");
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addOptionalMethodCallTail() {
+    addChunkWithTextNoCopy(
+        CodeCompletionString::Chunk::ChunkKind::OptionalMethodCallTail, "?");
+  }
+
+  void addTypeAnnotation(StringRef Type) {
+    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::TypeAnnotation,
+                     Type);
+    getLastChunk().setIsAnnotation();
+  }
+
+  void addTypeAnnotation(Type T, const PrintOptions &PO,
+                         NonRecursivePrintOptions nrOptions = std::nullopt,
+                         StringRef suffix = "");
+
+  void addBraceStmtWithCursor(StringRef Description = "") {
+    addChunkWithText(
+        CodeCompletionString::Chunk::ChunkKind::BraceStmtWithCursor,
+        Description);
+  }
+
+  void addWhitespace(StringRef space) {
+    addChunkWithText(CodeCompletionString::Chunk::ChunkKind::Whitespace, space);
+  }
+
+  void addAnnotatedWhitespace(StringRef space) {
+    addWhitespace(space);
+    getLastChunk().setIsAnnotation();
+  }
+
+  /// Adds a \c DeclBaseName and escapes identifiers with backticks if necessary
+  void addValueBaseName(DeclBaseName Name, bool IsMember);
+
+  /// Build argument patterns for calling. Returns \c true if any content was
+  /// added to \p Builder. If \p declParams is non-empty, the size must match
+  /// with \p typeParams.
+  bool addCallArgumentPatterns(ArrayRef<AnyFunctionType::Param> typeParams,
+                               ArrayRef<const ParamDecl *> declParams,
+                               const DeclContext *DC,
+                               GenericSignature genericSig,
+                               DefaultArgumentOutputMode defaultArgsMode =
+                                   DefaultArgumentOutputMode::Interesting,
+                               bool includeDefaultValues = false);
+
+  /// Build argument patterns for calling. Returns \c true if any content was
+  /// added to \p Builder. If \p Params is non-nullptr, \F
+  bool addCallArgumentPatterns(const AnyFunctionType *AFT,
+                               const ParameterList *Params,
+                               const DeclContext *DC,
+                               GenericSignature genericSig,
+                               DefaultArgumentOutputMode defaultArgsMode =
+                                   DefaultArgumentOutputMode::Interesting,
+                               bool includeDefaultValues = false);
+
+  void addTypeAnnotation(Type T, const DeclContext *DC,
+                         GenericSignature genericSig = GenericSignature());
+
+  void addTypeAnnotationForImplicitlyUnwrappedOptional(
+      Type T, const DeclContext *DC,
+      GenericSignature genericSig = GenericSignature(),
+      bool dynamicOrOptional = false);
+
+  void addEffectsSpecifiers(const AnyFunctionType *AFT,
+                            const AbstractFunctionDecl *AFD,
+                            bool forceAsync = false);
+
+  CodeCompletionString *createCompletionString() {
+    return CodeCompletionString::create(Allocator, Chunks);
+  }
+
+  ArrayRef<CodeCompletionString::Chunk> getChunks() { return Chunks; }
+};
+
+} // end namespace ide
+} // end namespace swift
+
+#endif // SWIFT_IDE_CODECOMPLETIONSTRINGBUILDER_H
diff --git a/lib/IDE/CodeCompletionStringPrinter.cpp b/lib/IDE/CodeCompletionStringPrinter.cpp
index af0f2331deb36..a739b9ca7869a 100644
--- a/lib/IDE/CodeCompletionStringPrinter.cpp
+++ b/lib/IDE/CodeCompletionStringPrinter.cpp
@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/IDE/CodeCompletionStringPrinter.h"
-#include "CodeCompletionResultBuilder.h"
+#include "CodeCompletionStringBuilder.h"
 #include "swift/AST/Module.h"
 #include "swift/Basic/Assertions.h"
 
diff --git a/lib/IDE/CompletionLookup.cpp b/lib/IDE/CompletionLookup.cpp
index e186a39d422a1..0deb5bcfb7d15 100644
--- a/lib/IDE/CompletionLookup.cpp
+++ b/lib/IDE/CompletionLookup.cpp
@@ -19,6 +19,7 @@
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/SourceFile.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/IDE/CodeCompletionStringPrinter.h"
 
 using namespace swift;
 using namespace swift::ide;
@@ -104,12 +105,18 @@ static Type defaultTypeLiteralKind(CodeCompletionLiteralKind kind,
   llvm_unreachable("Unhandled CodeCompletionLiteralKind in switch.");
 }
 
-/// Whether funcType has a single argument (not including defaulted arguments)
-/// that is of type () -> ().
-static bool hasTrivialTrailingClosure(const FuncDecl *FD,
-                                      AnyFunctionType *funcType) {
-  ParameterListInfo paramInfo(funcType->getParams(), FD,
-                              /*skipCurriedSelf*/ FD->hasCurriedSelf());
+/// Whether the provided type has a single argument (not including defaulted
+/// arguments) that is of type () -> ().
+static bool hasTrivialTrailingClosure(const ValueDecl *VD, Type type) {
+  if (!VD->hasParameterList())
+    return false;
+
+  auto *funcType = type->getAs<AnyFunctionType>();
+  if (!funcType)
+    return false;
+
+  ParameterListInfo paramInfo(funcType->getParams(), VD,
+                              /*skipCurriedSelf*/ VD->hasCurriedSelf());
 
   if (paramInfo.size() - paramInfo.numNonDefaultedParameters() == 1) {
     auto param = funcType->getParams().back();
@@ -381,6 +388,23 @@ void CompletionLookup::addImportModuleNames() {
   }
 }
 
+void CompletionLookup::addUsingSpecifiers() {
+  for (unsigned i = 0,
+                n = static_cast<unsigned>(UsingSpecifier::LastSpecifier) + 1;
+       i != n; ++i) {
+    CodeCompletionResultBuilder Builder = makeResultBuilder(
+        CodeCompletionResultKind::Keyword, SemanticContextKind::None);
+    switch (static_cast<UsingSpecifier>(i)) {
+    case UsingSpecifier::MainActor:
+      Builder.addTextChunk("@MainActor");
+      break;
+    case UsingSpecifier::Nonisolated:
+      Builder.addTextChunk("nonisolated");
+      break;
+    }
+  }
+}
+
 SemanticContextKind
 CompletionLookup::getSemanticContext(const Decl *D, DeclVisibilityKind Reason,
                                      DynamicLookupInfo dynamicLookupInfo) {
@@ -474,36 +498,7 @@ CompletionLookup::makeResultBuilder(CodeCompletionResultKind kind,
 
 void CompletionLookup::addValueBaseName(CodeCompletionResultBuilder &Builder,
                                         DeclBaseName Name) {
-  auto NameStr = Name.userFacingName();
-  if (Name.mustAlwaysBeEscaped()) {
-    // Names that are raw identifiers must always be escaped regardless of
-    // their position.
-    SmallString<16> buffer;
-    Builder.addBaseName(Builder.escapeWithBackticks(NameStr, buffer));
-    return;
-  }
-
-  bool shouldEscapeKeywords;
-  if (Name.isSpecial()) {
-    // Special names (i.e. 'init') are always displayed as its user facing
-    // name.
-    shouldEscapeKeywords = false;
-  } else if (ExprType) {
-    // After dot. User can write any keyword after '.' except for `init` and
-    // `self`. E.g. 'func `init`()' must be called by 'expr.`init`()'.
-    shouldEscapeKeywords = NameStr == "self" || NameStr == "init";
-  } else {
-    // As primary expresson. We have to escape almost every keywords except
-    // for 'self' and 'Self'.
-    shouldEscapeKeywords = NameStr != "self" && NameStr != "Self";
-  }
-
-  if (!shouldEscapeKeywords) {
-    Builder.addBaseName(NameStr);
-  } else {
-    SmallString<16> buffer;
-    Builder.addBaseName(Builder.escapeKeyword(NameStr, true, buffer));
-  }
+  Builder.addValueBaseName(Name, /*IsMember=*/bool(ExprType));
 }
 
 void CompletionLookup::addIdentifier(CodeCompletionResultBuilder &Builder,
@@ -529,94 +524,19 @@ void CompletionLookup::addLeadingDot(CodeCompletionResultBuilder &Builder) {
 
 void CompletionLookup::addTypeAnnotation(CodeCompletionResultBuilder &Builder,
                                          Type T, GenericSignature genericSig) {
-  PrintOptions PO;
-  PO.OpaqueReturnTypePrinting =
-      PrintOptions::OpaqueReturnTypePrintingMode::WithoutOpaqueKeyword;
-  if (auto typeContext = CurrDeclContext->getInnermostTypeContext())
-    PO.setBaseType(typeContext->getDeclaredTypeInContext());
-  Builder.addTypeAnnotation(eraseArchetypes(T, genericSig), PO);
+  Builder.addTypeAnnotation(T, CurrDeclContext, genericSig);
   Builder.setResultTypes(T);
 }
 
 void CompletionLookup::addTypeAnnotationForImplicitlyUnwrappedOptional(
     CodeCompletionResultBuilder &Builder, Type T, GenericSignature genericSig,
     bool dynamicOrOptional) {
-
-  std::string suffix;
-  // FIXME: This retains previous behavior, but in reality the type of dynamic
-  // lookups is IUO, not Optional as it is for the @optional attribute.
-  if (dynamicOrOptional) {
-    T = T->getOptionalObjectType();
-    suffix = "?";
-  }
-
-  PrintOptions PO;
-  PO.PrintOptionalAsImplicitlyUnwrapped = true;
-  PO.OpaqueReturnTypePrinting =
-      PrintOptions::OpaqueReturnTypePrintingMode::WithoutOpaqueKeyword;
-  if (auto typeContext = CurrDeclContext->getInnermostTypeContext())
-    PO.setBaseType(typeContext->getDeclaredTypeInContext());
-  Builder.addTypeAnnotation(eraseArchetypes(T, genericSig), PO, suffix);
+  Builder.addTypeAnnotationForImplicitlyUnwrappedOptional(
+      T, CurrDeclContext, genericSig, dynamicOrOptional);
   Builder.setResultTypes(T);
   Builder.setTypeContext(expectedTypeContext, CurrDeclContext);
 }
 
-/// For printing in code completion results, replace archetypes with
-/// protocol compositions.
-///
-/// FIXME: Perhaps this should be an option in PrintOptions instead.
-Type CompletionLookup::eraseArchetypes(Type type, GenericSignature genericSig) {
-  if (!genericSig)
-    return type;
-
-  if (auto *genericFuncType = type->getAs<GenericFunctionType>()) {
-    assert(genericFuncType->getGenericSignature()->isEqual(genericSig) &&
-           "if not, just use the GFT's signature instead below");
-
-    SmallVector<AnyFunctionType::Param, 8> erasedParams;
-    for (const auto &param : genericFuncType->getParams()) {
-      auto erasedTy = eraseArchetypes(param.getPlainType(), genericSig);
-      erasedParams.emplace_back(param.withType(erasedTy));
-    }
-    return GenericFunctionType::get(
-        genericSig, erasedParams,
-        eraseArchetypes(genericFuncType->getResult(), genericSig),
-        genericFuncType->getExtInfo());
-  }
-
-  return type.transformRec([&](Type t) -> std::optional<Type> {
-    // FIXME: Code completion should only deal with one or the other,
-    // and not both.
-    if (auto *archetypeType = t->getAs<ArchetypeType>()) {
-      // Don't erase opaque archetype.
-      if (isa<OpaqueTypeArchetypeType>(archetypeType) &&
-          archetypeType->isRoot())
-        return std::nullopt;
-
-      auto genericSig = archetypeType->getGenericEnvironment()->getGenericSignature();
-      auto upperBound = genericSig->getUpperBound(
-          archetypeType->getInterfaceType(),
-          /*forExistentialSelf=*/false,
-          /*withParameterizedProtocols=*/false);
-
-      if (!upperBound->isAny())
-        return upperBound;
-    }
-
-    if (t->isTypeParameter()) {
-      auto upperBound = genericSig->getUpperBound(
-          t,
-          /*forExistentialSelf=*/false,
-          /*withParameterizedProtocols=*/false);
-
-      if (!upperBound->isAny())
-        return upperBound;
-    }
-
-    return std::nullopt;
-  });
-}
-
 Type CompletionLookup::getTypeOfMember(const ValueDecl *VD,
                                        DynamicLookupInfo dynamicLookupInfo) {
   switch (dynamicLookupInfo.getKind()) {
@@ -773,7 +693,7 @@ Type CompletionLookup::getTypeOfMember(const ValueDecl *VD, Type ExprType) {
 
       // For a GenericFunctionType, we only want to substitute the
       // param/result types, as otherwise we might end up with a bad generic
-      // signature if there are UnresolvedTypes present in the base type. Note
+      // signature if there are ErrorTypes present in the base type. Note
       // we pass in DesugarMemberTypes so that we see the actual concrete type
       // witnesses instead of type alias types.
       if (auto *GFT = T->getAs<GenericFunctionType>()) {
@@ -934,99 +854,8 @@ void CompletionLookup::addVarDeclRef(const VarDecl *VD,
         AFT = AFT->getResult()->getAs<AnyFunctionType>();
         assert(AFT);
       }
-      addEffectsSpecifiers(Builder, AFT, Accessor);
-    }
-  }
-}
-
-/// Return whether \p param has a non-desirable default value for code
-/// completion.
-///
-/// 'ClangImporter::Implementation::inferDefaultArgument()' automatically adds
-/// default values for some parameters;
-///   * NS_OPTIONS enum type with the name '...Options'.
-///   * NSDictionary and labeled 'options', 'attributes', or 'userInfo'.
-///
-/// But sometimes, this behavior isn't really desirable. This function add a
-/// heuristic where if a parameter matches all the following condition, we
-/// consider the imported default value is _not_ desirable:
-///   * it is the first parameter,
-///   * it doesn't have an argument label, and
-///   * the imported function base name ends with those words
-/// For example, ClangImporter imports:
-///
-///   -(void)addAttributes:(NSDictionary *)attrs, options:(NSDictionary *)opts;
-///
-/// as:
-///
-///   func addAttributes(_ attrs: [AnyHashable:Any] = [:],
-///                      options opts: [AnyHashable:Any] = [:])
-///
-/// In this case, we don't want 'attrs' defaulted because the function name have
-/// 'Attribute' in its name so calling 'value.addAttribute()' doesn't make
-/// sense, but we _do_ want to keep 'opts' defaulted.
-///
-/// Note that:
-///
-///   -(void)performWithOptions:(NSDictionary *) opts;
-///
-/// This doesn't match the condition because the base name of the function in
-/// Swift is 'peform':
-///
-///   func perform(options opts: [AnyHashable:Any] = [:])
-///
-bool isNonDesirableImportedDefaultArg(const ParamDecl *param) {
-  auto kind = param->getDefaultArgumentKind();
-  if (kind != DefaultArgumentKind::EmptyArray &&
-      kind != DefaultArgumentKind::EmptyDictionary)
-    return false;
-
-  if (!param->getArgumentName().empty())
-    return false;
-
-  auto *func = dyn_cast<FuncDecl>(param->getDeclContext());
-  if (!func->hasClangNode())
-    return false;
-  if (func->getParameters()->front() != param)
-    return false;
-  if (func->getBaseName().isSpecial())
-    return false;
-
-  auto baseName = func->getBaseName().getIdentifier().str();
-  switch (kind) {
-  case DefaultArgumentKind::EmptyArray:
-    return (baseName.ends_with("Options"));
-  case DefaultArgumentKind::EmptyDictionary:
-    return (baseName.ends_with("Options") || baseName.ends_with("Attributes") ||
-            baseName.ends_with("UserInfo"));
-  default:
-    llvm_unreachable("unhandled DefaultArgumentKind");
-  }
-}
-
-bool CompletionLookup::hasInterestingDefaultValue(const ParamDecl *param) {
-  if (!param)
-    return false;
-
-  switch (param->getDefaultArgumentKind()) {
-  case DefaultArgumentKind::Normal:
-  case DefaultArgumentKind::NilLiteral:
-  case DefaultArgumentKind::StoredProperty:
-  case DefaultArgumentKind::Inherited:
-    return true;
-
-  case DefaultArgumentKind::EmptyArray:
-  case DefaultArgumentKind::EmptyDictionary:
-    if (isNonDesirableImportedDefaultArg(param))
-      return false;
-    return true;
-
-  case DefaultArgumentKind::None:
-#define MAGIC_IDENTIFIER(NAME, STRING)                                         \
-  case DefaultArgumentKind::NAME:
-#include "swift/AST/MagicIdentifierKinds.def"
-  case DefaultArgumentKind::ExpressionMacro:
-    return false;
+      Builder.addEffectsSpecifiers(AFT, Accessor);
+    }
   }
 }
 
@@ -1041,92 +870,6 @@ bool CompletionLookup::shouldAddItemWithoutDefaultArgs(
   return false;
 }
 
-bool CompletionLookup::addCallArgumentPatterns(
-    CodeCompletionResultBuilder &Builder,
-    ArrayRef<AnyFunctionType::Param> typeParams,
-    ArrayRef<const ParamDecl *> declParams, GenericSignature genericSig,
-    bool includeDefaultArgs) {
-  assert(declParams.empty() || typeParams.size() == declParams.size());
-
-  bool modifiedBuilder = false;
-  bool needComma = false;
-  // Iterate over each parameter.
-  for (unsigned i = 0; i != typeParams.size(); ++i) {
-    auto &typeParam = typeParams[i];
-
-    Identifier argName = typeParam.getLabel();
-    Identifier bodyName;
-    bool isIUO = false;
-    bool hasDefault = false;
-    if (!declParams.empty()) {
-      const ParamDecl *PD = declParams[i];
-      hasDefault =
-          PD->isDefaultArgument() && !isNonDesirableImportedDefaultArg(PD);
-      // Skip default arguments if we're either not including them or they
-      // aren't interesting
-      if (hasDefault &&
-          (!includeDefaultArgs || !hasInterestingDefaultValue(PD)))
-        continue;
-
-      argName = PD->getArgumentName();
-      bodyName = PD->getParameterName();
-      isIUO = PD->isImplicitlyUnwrappedOptional();
-    }
-
-    bool isVariadic = typeParam.isVariadic();
-    bool isInOut = typeParam.isInOut();
-    bool isAutoclosure = typeParam.isAutoClosure();
-    Type paramTy = typeParam.getPlainType();
-    if (isVariadic)
-      paramTy = ParamDecl::getVarargBaseTy(paramTy);
-
-    Type contextTy;
-    if (auto typeContext = CurrDeclContext->getInnermostTypeContext())
-      contextTy = typeContext->getDeclaredTypeInContext();
-
-    if (needComma)
-      Builder.addComma();
-    Builder.addCallArgument(argName, bodyName,
-                            eraseArchetypes(paramTy, genericSig), contextTy,
-                            isVariadic, isInOut, isIUO, isAutoclosure,
-                            /*IsLabeledTrailingClosure=*/false,
-                            /*IsForOperator=*/false, hasDefault);
-
-    modifiedBuilder = true;
-    needComma = true;
-  }
-
-  return modifiedBuilder;
-}
-
-bool CompletionLookup::addCallArgumentPatterns(
-    CodeCompletionResultBuilder &Builder, const AnyFunctionType *AFT,
-    const ParameterList *Params, GenericSignature genericSig,
-    bool includeDefaultArgs) {
-  ArrayRef<const ParamDecl *> declParams;
-  if (Params)
-    declParams = Params->getArray();
-  return addCallArgumentPatterns(Builder, AFT->getParams(), declParams,
-                                 genericSig, includeDefaultArgs);
-}
-
-void CompletionLookup::addEffectsSpecifiers(
-    CodeCompletionResultBuilder &Builder, const AnyFunctionType *AFT,
-    const AbstractFunctionDecl *AFD, bool forceAsync) {
-  assert(AFT != nullptr);
-
-  // 'async'.
-  if (forceAsync || (AFD && AFD->hasAsync()) ||
-      (AFT->hasExtInfo() && AFT->isAsync()))
-    Builder.addAnnotatedAsync();
-
-  // 'throws' or 'rethrows'.
-  if (AFD && AFD->getAttrs().hasAttribute<RethrowsAttr>())
-    Builder.addAnnotatedRethrows();
-  else if (AFT->hasExtInfo() && AFT->isThrowing())
-    Builder.addAnnotatedThrows();
-}
-
 void CompletionLookup::addPoundAvailable(std::optional<StmtKind> ParentKind) {
   if (ParentKind != StmtKind::If && ParentKind != StmtKind::Guard)
     return;
@@ -1232,7 +975,8 @@ void CompletionLookup::addSubscriptCallPattern(
   ArrayRef<const ParamDecl *> declParams;
   if (SD)
     declParams = SD->getIndices()->getArray();
-  addCallArgumentPatterns(Builder, AFT->getParams(), declParams, genericSig);
+  Builder.addCallArgumentPatterns(AFT->getParams(), declParams, CurrDeclContext,
+                                  genericSig);
   if (!HaveLParen)
     Builder.addRightBracket();
   else
@@ -1253,7 +997,8 @@ void CompletionLookup::addFunctionCallPattern(
 
   // Add the pattern, possibly including any default arguments.
   auto addPattern = [&](ArrayRef<const ParamDecl *> declParams = {},
-                        bool includeDefaultArgs = true) {
+                        DefaultArgumentOutputMode defaultArgsMode =
+                            DefaultArgumentOutputMode::Interesting) {
     CodeCompletionResultBuilder Builder = makeResultBuilder(
         AFD ? CodeCompletionResultKind::Declaration
             : CodeCompletionResultKind::Pattern,
@@ -1271,8 +1016,9 @@ void CompletionLookup::addFunctionCallPattern(
     else
       Builder.addAnnotatedLeftParen();
 
-    addCallArgumentPatterns(Builder, AFT->getParams(), declParams, genericSig,
-                            includeDefaultArgs);
+    Builder.addCallArgumentPatterns(AFT->getParams(), declParams,
+                                    CurrDeclContext, genericSig,
+                                    defaultArgsMode);
 
     // The rparen matches the lparen here so that we insert both or neither.
     if (!HaveLParen)
@@ -1280,7 +1026,7 @@ void CompletionLookup::addFunctionCallPattern(
     else
       Builder.addAnnotatedRightParen();
 
-    addEffectsSpecifiers(Builder, AFT, AFD);
+    Builder.addEffectsSpecifiers(AFT, AFD);
 
     if (AFD && AFD->isImplicitlyUnwrappedOptional())
       addTypeAnnotationForImplicitlyUnwrappedOptional(Builder, AFT->getResult(),
@@ -1322,13 +1068,14 @@ void CompletionLookup::addFunctionCallPattern(
          AFT->getParams()[0].getLabel().empty());
 
     if (isImplicitlyCurriedInstanceMethod) {
-      addPattern({AFD->getImplicitSelfDecl()}, /*includeDefaultArgs=*/true);
+      addPattern({AFD->getImplicitSelfDecl()},
+                 DefaultArgumentOutputMode::Interesting);
     } else {
       if (shouldAddItemWithoutDefaultArgs(AFD))
         addPattern(AFD->getParameters()->getArray(),
-                   /*includeDefaultArgs=*/false);
+                   DefaultArgumentOutputMode::None);
       addPattern(AFD->getParameters()->getArray(),
-                 /*includeDefaultArgs=*/true);
+                 DefaultArgumentOutputMode::Interesting);
     }
   }
 }
@@ -1404,7 +1151,8 @@ void CompletionLookup::addMethodCall(const FuncDecl *FD,
   analyzeActorIsolation(FD, AFT, implictlyAsync, NotRecommended);
 
   // Add the method, possibly including any default arguments.
-  auto addMethodImpl = [&](bool includeDefaultArgs = true,
+  auto addMethodImpl = [&](DefaultArgumentOutputMode defaultArgsMode =
+                               DefaultArgumentOutputMode::Interesting,
                            bool trivialTrailingClosure = false) {
     CodeCompletionResultBuilder Builder =
         makeResultBuilder(CodeCompletionResultKind::Declaration,
@@ -1436,20 +1184,20 @@ void CompletionLookup::addMethodCall(const FuncDecl *FD,
     }
     if (IsImplicitlyCurriedInstanceMethod) {
       Builder.addLeftParen();
-      addCallArgumentPatterns(
-          Builder, AFT->getParams(), {FD->getImplicitSelfDecl()},
-          FD->getGenericSignatureOfContext(), includeDefaultArgs);
+      Builder.addCallArgumentPatterns(
+          AFT->getParams(), {FD->getImplicitSelfDecl()}, CurrDeclContext,
+          FD->getGenericSignatureOfContext(), defaultArgsMode);
       Builder.addRightParen();
     } else if (trivialTrailingClosure) {
       Builder.addBraceStmtWithCursor(" { code }");
-      addEffectsSpecifiers(Builder, AFT, FD, implictlyAsync);
+      Builder.addEffectsSpecifiers(AFT, FD, implictlyAsync);
     } else {
       Builder.addLeftParen();
-      addCallArgumentPatterns(Builder, AFT, FD->getParameters(),
-                              FD->getGenericSignatureOfContext(),
-                              includeDefaultArgs);
+      Builder.addCallArgumentPatterns(AFT, FD->getParameters(), CurrDeclContext,
+                                      FD->getGenericSignatureOfContext(),
+                                      defaultArgsMode);
       Builder.addRightParen();
-      addEffectsSpecifiers(Builder, AFT, FD, implictlyAsync);
+      Builder.addEffectsSpecifiers(AFT, FD, implictlyAsync);
     }
 
     // Build type annotation.
@@ -1460,10 +1208,13 @@ void CompletionLookup::addMethodCall(const FuncDecl *FD,
     bool IsIUO = !IsImplicitlyCurriedInstanceMethod &&
                  FD->isImplicitlyUnwrappedOptional();
 
+    NonRecursivePrintOptions nrOptions;
+    if (IsIUO)
+      nrOptions |= NonRecursivePrintOption::ImplicitlyUnwrappedOptional;
+
     PrintOptions PO;
     PO.OpaqueReturnTypePrinting =
         PrintOptions::OpaqueReturnTypePrintingMode::WithoutOpaqueKeyword;
-    PO.PrintOptionalAsImplicitlyUnwrapped = IsIUO;
     if (auto typeContext = CurrDeclContext->getInnermostTypeContext())
       PO.setBaseType(typeContext->getDeclaredTypeInContext());
     Type AnnotationTy =
@@ -1485,7 +1236,7 @@ void CompletionLookup::addMethodCall(const FuncDecl *FD,
             // What's left is the result type.
             if (AnnotationTy->isVoid())
               AnnotationTy = Ctx.getVoidDecl()->getDeclaredInterfaceType();
-            AnnotationTy.print(printer, PO);
+            AnnotationTy.print(printer, PO, nrOptions);
             printer.printTypePost(TL);
           });
     } else {
@@ -1501,7 +1252,7 @@ void CompletionLookup::addMethodCall(const FuncDecl *FD,
       // What's left is the result type.
       if (AnnotationTy->isVoid())
         AnnotationTy = Ctx.getVoidDecl()->getDeclaredInterfaceType();
-      AnnotationTy.print(OS, PO);
+      AnnotationTy.print(OS, PO, nrOptions);
       Builder.addTypeAnnotation(TypeStr);
     }
 
@@ -1520,11 +1271,11 @@ void CompletionLookup::addMethodCall(const FuncDecl *FD,
     addMethodImpl();
   } else {
     if (trivialTrailingClosure)
-      addMethodImpl(/*includeDefaultArgs=*/false,
+      addMethodImpl(DefaultArgumentOutputMode::None,
                     /*trivialTrailingClosure=*/true);
     if (shouldAddItemWithoutDefaultArgs(FD))
-      addMethodImpl(/*includeDefaultArgs=*/false);
-    addMethodImpl(/*includeDefaultArgs=*/true);
+      addMethodImpl(DefaultArgumentOutputMode::None);
+    addMethodImpl(DefaultArgumentOutputMode::Interesting);
   }
 }
 
@@ -1553,7 +1304,7 @@ void CompletionLookup::addConstructorCall(const ConstructorDecl *CD,
     return;
 
   // Add the constructor, possibly including any default arguments.
-  auto addConstructorImpl = [&](bool includeDefaultArgs = true) {
+  auto addConstructorImpl = [&](DefaultArgumentOutputMode defaultArgsMode) {
     CodeCompletionResultBuilder Builder =
         makeResultBuilder(CodeCompletionResultKind::Declaration,
                           getSemanticContext(CD, Reason, dynamicLookupInfo));
@@ -1584,9 +1335,9 @@ void CompletionLookup::addConstructorCall(const ConstructorDecl *CD,
     else
       Builder.addAnnotatedLeftParen();
 
-    addCallArgumentPatterns(Builder, ConstructorType, CD->getParameters(),
-                            CD->getGenericSignatureOfContext(),
-                            includeDefaultArgs);
+    Builder.addCallArgumentPatterns(
+        ConstructorType, CD->getParameters(), CurrDeclContext,
+        CD->getGenericSignatureOfContext(), defaultArgsMode);
 
     // The rparen matches the lparen here so that we insert both or neither.
     if (!HaveLParen)
@@ -1594,7 +1345,7 @@ void CompletionLookup::addConstructorCall(const ConstructorDecl *CD,
     else
       Builder.addAnnotatedRightParen();
 
-    addEffectsSpecifiers(Builder, ConstructorType, CD);
+    Builder.addEffectsSpecifiers(ConstructorType, CD);
 
     if (!Result.has_value())
       Result = ConstructorType->getResult();
@@ -1609,8 +1360,8 @@ void CompletionLookup::addConstructorCall(const ConstructorDecl *CD,
   };
 
   if (ConstructorType && shouldAddItemWithoutDefaultArgs(CD))
-    addConstructorImpl(/*includeDefaultArgs=*/false);
-  addConstructorImpl();
+    addConstructorImpl(DefaultArgumentOutputMode::None);
+  addConstructorImpl(DefaultArgumentOutputMode::Interesting);
 }
 
 void CompletionLookup::addConstructorCallsForType(
@@ -1683,8 +1434,10 @@ void CompletionLookup::addSubscriptCall(const SubscriptDecl *SD,
   }
 
   Builder.addLeftBracket();
-  addCallArgumentPatterns(Builder, subscriptType, SD->getIndices(),
-                          SD->getGenericSignatureOfContext(), true);
+  Builder.addCallArgumentPatterns(subscriptType, SD->getIndices(),
+                                  CurrDeclContext,
+                                  SD->getGenericSignatureOfContext(),
+                                  DefaultArgumentOutputMode::Interesting);
   Builder.addRightBracket();
 
   // Add a type annotation.
@@ -1875,9 +1628,9 @@ void CompletionLookup::addEnumElementRef(const EnumElementDecl *EED,
 
   if (EnumType->is<FunctionType>()) {
     Builder.addLeftParen();
-    addCallArgumentPatterns(Builder, EnumType->castTo<FunctionType>(),
-                            EED->getParameterList(),
-                            EED->getGenericSignatureOfContext());
+    Builder.addCallArgumentPatterns(EnumType->castTo<FunctionType>(),
+                                    EED->getParameterList(), CurrDeclContext,
+                                    EED->getGenericSignatureOfContext());
     Builder.addRightParen();
 
     // Extract result as the enum type.
@@ -1946,22 +1699,9 @@ static StringRef getTypeAnnotationString(const MacroDecl *MD,
   return {stash.data(), stash.size()};
 }
 
-void CompletionLookup::addMacroExpansion(const MacroDecl *MD,
-                                         DeclVisibilityKind Reason) {
-  if (!MD->hasName() || !MD->isAccessibleFrom(CurrDeclContext) ||
-      MD->shouldHideFromEditor())
-    return;
-
-  OptionSet<CustomAttributeKind> expectedKinds =
-      expectedTypeContext.getExpectedCustomAttributeKinds();
-  if (expectedKinds) {
-    CodeCompletionMacroRoles expectedRoles =
-        getCompletionMacroRoles(expectedKinds);
-    CodeCompletionMacroRoles roles = getCompletionMacroRoles(MD);
-    if (!(roles & expectedRoles))
-      return;
-  }
-
+void CompletionLookup::addMacroCallArguments(const MacroDecl *MD,
+                                             DeclVisibilityKind Reason,
+                                             bool forTrivialTrailingClosure) {
   CodeCompletionResultBuilder Builder =
       makeResultBuilder(CodeCompletionResultKind::Declaration,
                         getSemanticContext(MD, Reason, DynamicLookupInfo()));
@@ -1969,12 +1709,13 @@ void CompletionLookup::addMacroExpansion(const MacroDecl *MD,
 
   addValueBaseName(Builder, MD->getBaseIdentifier());
 
-  Type macroType = MD->getInterfaceType();
-  if (MD->parameterList && MD->parameterList->size() > 0) {
+  if (forTrivialTrailingClosure) {
+    Builder.addBraceStmtWithCursor(" { code }");
+  } else if (MD->parameterList && MD->parameterList->size() > 0) {
+    auto *macroTy = MD->getInterfaceType()->castTo<AnyFunctionType>();
     Builder.addLeftParen();
-    addCallArgumentPatterns(Builder, macroType->castTo<AnyFunctionType>(),
-                            MD->parameterList,
-                            MD->getGenericSignature());
+    Builder.addCallArgumentPatterns(macroTy, MD->parameterList, CurrDeclContext,
+                                    MD->getGenericSignature());
     Builder.addRightParen();
   }
 
@@ -1988,6 +1729,28 @@ void CompletionLookup::addMacroExpansion(const MacroDecl *MD,
   }
 }
 
+void CompletionLookup::addMacroExpansion(const MacroDecl *MD,
+                                         DeclVisibilityKind Reason) {
+  if (!MD->hasName() || !MD->isAccessibleFrom(CurrDeclContext) ||
+      MD->shouldHideFromEditor())
+    return;
+
+  OptionSet<CustomAttributeKind> expectedKinds =
+      expectedTypeContext.getExpectedCustomAttributeKinds();
+  if (expectedKinds) {
+    CodeCompletionMacroRoles expectedRoles =
+        getCompletionMacroRoles(expectedKinds);
+    CodeCompletionMacroRoles roles = getCompletionMacroRoles(MD);
+    if (!(roles & expectedRoles))
+      return;
+  }
+
+  if (hasTrivialTrailingClosure(MD, MD->getInterfaceType()))
+    addMacroCallArguments(MD, Reason, /*forTrivialTrailingClosure*/ true);
+
+  addMacroCallArguments(MD, Reason);
+}
+
 void CompletionLookup::addKeyword(StringRef Name, Type TypeAnnotation,
                                   SemanticContextKind SK,
                                   CodeCompletionKeywordKind KeyKind,
@@ -2419,11 +2182,9 @@ bool CompletionLookup::tryModuleCompletions(Type ExprType,
     // If the module is shadowed by a separately imported overlay(s), look up
     // the symbols from the overlay(s) instead.
     SmallVector<ModuleDecl *, 1> ShadowingOrOriginal;
-    if (auto *SF = CurrDeclContext->getParentSourceFile()) {
-      SF->getSeparatelyImportedOverlays(M, ShadowingOrOriginal);
-      if (ShadowingOrOriginal.empty())
-        ShadowingOrOriginal.push_back(M);
-    }
+    CurrDeclContext->getSeparatelyImportedOverlays(M, ShadowingOrOriginal);
+    if (ShadowingOrOriginal.empty())
+      ShadowingOrOriginal.push_back(M);
     for (ModuleDecl *M : ShadowingOrOriginal) {
       RequestedResultsTy Request =
           RequestedResultsTy::fromModule(M, Filter).needLeadingDot(needDot());
@@ -3139,6 +2900,10 @@ void CompletionLookup::getAttributeDeclParamCompletions(
     break;
   case ParameterizedDeclAttributeKind::Nonisolated:
     addDeclAttrParamKeyword("unsafe", /*Parameters=*/{}, "", false);
+    addDeclAttrParamKeyword("nonsending", /*Parameters=*/{}, "", false);
+    break;
+  case ParameterizedDeclAttributeKind::InheritActorContext:
+    addDeclAttrParamKeyword("always", /*Parameters=*/{}, "", false);
     break;
   case ParameterizedDeclAttributeKind::AccessControl:
     addDeclAttrParamKeyword("set", /*Parameters=*/{}, "", false);
@@ -3236,6 +3001,11 @@ void CompletionLookup::getAttributeDeclParamCompletions(
         getStoredPropertyCompletions(NT);
       }
     }
+    break;
+  }
+  case ParameterizedDeclAttributeKind::Nonexhaustive: {
+    addDeclAttrParamKeyword("warn", /*Parameters=*/{}, "", false);
+    break;
   }
   }
 }
diff --git a/lib/IDE/ConformingMethodList.cpp b/lib/IDE/ConformingMethodList.cpp
index 7e95a5ad82f13..72987b054504f 100644
--- a/lib/IDE/ConformingMethodList.cpp
+++ b/lib/IDE/ConformingMethodList.cpp
@@ -12,6 +12,7 @@
 
 #include "swift/IDE/ConformingMethodList.h"
 #include "ExprContextAnalysis.h"
+#include "ReadyForTypeCheckingCallback.h"
 #include "swift/AST/ASTDemangler.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/GenericEnvironment.h"
@@ -20,8 +21,8 @@
 #include "swift/Basic/Assertions.h"
 #include "swift/IDE/TypeCheckCompletionCallback.h"
 #include "swift/Parse/IDEInspectionCallbacks.h"
-#include "swift/Sema/IDETypeChecking.h"
 #include "swift/Sema/ConstraintSystem.h"
+#include "swift/Sema/IDETypeChecking.h"
 #include "clang/AST/Attr.h"
 #include "clang/AST/Decl.h"
 
@@ -30,7 +31,7 @@ using namespace ide;
 
 namespace {
 class ConformingMethodListCallbacks : public CodeCompletionCallbacks,
-                                      public DoneParsingCallback {
+                                      public ReadyForTypeCheckingCallback {
   ArrayRef<const char *> ExpectedTypeNames;
   ConformingMethodListConsumer &Consumer;
   SourceLoc Loc;
@@ -45,8 +46,8 @@ class ConformingMethodListCallbacks : public CodeCompletionCallbacks,
   ConformingMethodListCallbacks(Parser &P,
                                 ArrayRef<const char *> ExpectedTypeNames,
                                 ConformingMethodListConsumer &Consumer)
-      : CodeCompletionCallbacks(P), DoneParsingCallback(),
-        ExpectedTypeNames(ExpectedTypeNames), Consumer(Consumer) {}
+      : CodeCompletionCallbacks(P), ExpectedTypeNames(ExpectedTypeNames),
+        Consumer(Consumer) {}
 
   // Only handle callbacks for suffix completions.
   // {
@@ -54,7 +55,7 @@ class ConformingMethodListCallbacks : public CodeCompletionCallbacks,
   void completePostfixExpr(CodeCompletionExpr *E, bool hasSpace) override;
   // }
 
-  void doneParsing(SourceFile *SrcFile) override;
+  void readyForTypeChecking(SourceFile *SrcFile) override;
 };
 
 void ConformingMethodListCallbacks::completeDotExpr(CodeCompletionExpr *E,
@@ -101,7 +102,7 @@ class ConformingMethodListCallback : public TypeCheckCompletionCallback {
   ArrayRef<Result> getResults() const { return Results; }
 };
 
-void ConformingMethodListCallbacks::doneParsing(SourceFile *SrcFile) {
+void ConformingMethodListCallbacks::readyForTypeChecking(SourceFile *SrcFile) {
   if (!CCExpr || !CCExpr->getBase())
     return;
 
@@ -109,7 +110,7 @@ void ConformingMethodListCallbacks::doneParsing(SourceFile *SrcFile) {
   {
     llvm::SaveAndRestore<TypeCheckCompletionCallback *> CompletionCollector(
         Context.CompletionCallback, &TypeCheckCallback);
-    typeCheckContextAt(
+    swift::typeCheckASTNodeAtLoc(
         TypeCheckASTNodeAtLocContext::declContext(CurDeclContext),
         CCExpr->getLoc());
   }
@@ -122,7 +123,7 @@ void ConformingMethodListCallbacks::doneParsing(SourceFile *SrcFile) {
   Type T = Res.Ty;
   WithSolutionSpecificVarTypesRAII VarType(Res.SolutionSpecificVarTypes);
 
-  if (!T || T->is<ErrorType>() || T->is<UnresolvedType>())
+  if (!T || T->is<ErrorType>())
     return;
 
   T = T->getRValueType();
diff --git a/lib/IDE/CursorInfo.cpp b/lib/IDE/CursorInfo.cpp
index 4548070cee6ac..3e9dc9db6a345 100644
--- a/lib/IDE/CursorInfo.cpp
+++ b/lib/IDE/CursorInfo.cpp
@@ -12,6 +12,7 @@
 
 #include "swift/IDE/CursorInfo.h"
 #include "ExprContextAnalysis.h"
+#include "ReadyForTypeCheckingCallback.h"
 #include "swift/AST/ASTDemangler.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/NameLookup.h"
@@ -374,14 +375,14 @@ class CursorInfoTypeCheckSolutionCallback : public TypeCheckCompletionCallback {
 
 // MARK: - CursorInfoDoneParsingCallback
 
-class CursorInfoDoneParsingCallback : public DoneParsingCallback {
+class CursorInfoDoneParsingCallback : public ReadyForTypeCheckingCallback {
   CursorInfoConsumer &Consumer;
   SourceLoc RequestedLoc;
 
 public:
   CursorInfoDoneParsingCallback(Parser &P, CursorInfoConsumer &Consumer,
                                 SourceLoc RequestedLoc)
-      : DoneParsingCallback(), Consumer(Consumer), RequestedLoc(RequestedLoc) {}
+      : Consumer(Consumer), RequestedLoc(RequestedLoc) {}
 
 private:
   /// Shared core of `getExprResult` and `getDeclResult`.
@@ -406,7 +407,7 @@ class CursorInfoDoneParsingCallback : public DoneParsingCallback {
       return {};
     }
 
-    if (Node.is<Expr *>()) {
+    if (isa<Expr *>(Node)) {
       // If we are performing cursor info on an expression, type check the
       // referenced decls so that all their parent closures are type-checked
       // (see comment in typeCheckDeclAndParentClosures).
@@ -489,7 +490,7 @@ class CursorInfoDoneParsingCallback : public DoneParsingCallback {
                      SrcFile, Finder);
   }
 
-  void doneParsing(SourceFile *SrcFile) override {
+  void readyForTypeChecking(SourceFile *SrcFile) override {
     if (!SrcFile) {
       return;
     }
diff --git a/lib/IDE/ExprCompletion.cpp b/lib/IDE/ExprCompletion.cpp
index f7eb47c15d3e1..334363f1dbff9 100644
--- a/lib/IDE/ExprCompletion.cpp
+++ b/lib/IDE/ExprCompletion.cpp
@@ -119,6 +119,12 @@ void ExprTypeCheckCompletionCallback::collectResults(
     UnifiedCanHandleAsync |= Result.IsInAsyncContext;
   }
 
+  // If we didn't find any results, at least try to collect unqualified results.
+  if (Results.empty()) {
+    Lookup.getValueCompletionsInDeclContext(CCLoc);
+    Lookup.getSelfTypeCompletionInDeclContext(CCLoc, /*isForDeclResult=*/false);
+  }
+
   collectCompletionResults(CompletionCtx, Lookup, DC, UnifiedTypeContext,
                            UnifiedCanHandleAsync);
 }
diff --git a/lib/IDE/ExprContextAnalysis.cpp b/lib/IDE/ExprContextAnalysis.cpp
index 458ff11db8891..a690c621a9faa 100644
--- a/lib/IDE/ExprContextAnalysis.cpp
+++ b/lib/IDE/ExprContextAnalysis.cpp
@@ -40,45 +40,6 @@
 using namespace swift;
 using namespace ide;
 
-//===----------------------------------------------------------------------===//
-// typeCheckContextAt(DeclContext, SourceLoc)
-//===----------------------------------------------------------------------===//
-
-void swift::ide::typeCheckContextAt(TypeCheckASTNodeAtLocContext TypeCheckCtx,
-                                    SourceLoc Loc) {
-  // Make sure the extension has been bound.
-  auto DC = TypeCheckCtx.getDeclContext();
-  // Even if the extension is invalid (e.g. nested in a function or another
-  // type), we want to know the "intended nominal" of the extension so that
-  // we can know the type of 'Self'.
-  SmallVector<ExtensionDecl *, 1> extensions;
-  for (auto typeCtx = DC->getInnermostTypeContext(); typeCtx != nullptr;
-       typeCtx = typeCtx->getParent()->getInnermostTypeContext()) {
-    if (auto *ext = dyn_cast<ExtensionDecl>(typeCtx))
-      extensions.push_back(ext);
-  }
-  while (!extensions.empty()) {
-    extensions.back()->computeExtendedNominal();
-    extensions.pop_back();
-  }
-
-  // If the completion happens in the inheritance clause of the extension,
-  // 'DC' is the parent of the extension. We need to iterate the top level
-  // decls to find it. In theory, we don't need the extended nominal in the
-  // inheritance clause, but ASTScope lookup requires that. We don't care
-  // unless 'DC' is not 'SourceFile' because non-toplevel extensions are
-  // 'canNeverBeBound()' anyway.
-  if (auto *SF = dyn_cast<SourceFile>(DC)) {
-    auto &SM = DC->getASTContext().SourceMgr;
-    for (auto *decl : SF->getTopLevelDecls())
-      if (auto *ext = dyn_cast<ExtensionDecl>(decl))
-        if (SM.rangeContainsTokenLoc(ext->getSourceRange(), Loc))
-          ext->computeExtendedNominal();
-  }
-
-  swift::typeCheckASTNodeAtLoc(TypeCheckCtx, Loc);
-}
-
 //===----------------------------------------------------------------------===//
 // findParsedExpr(DeclContext, Expr)
 //===----------------------------------------------------------------------===//
diff --git a/lib/IDE/ExprContextAnalysis.h b/lib/IDE/ExprContextAnalysis.h
index 17f31412b6999..8e344283c388d 100644
--- a/lib/IDE/ExprContextAnalysis.h
+++ b/lib/IDE/ExprContextAnalysis.h
@@ -28,11 +28,6 @@ class ValueDecl;
 namespace ide {
 enum class SemanticContextKind : uint8_t;
 
-/// Type check parent contexts of the given decl context, and the body of the
-/// given context until \c Loc if the context is a function body.
-void typeCheckContextAt(TypeCheckASTNodeAtLocContext TypeCheckCtx,
-                        SourceLoc Loc);
-
 /// From \p DC, find and returns the outer most expression which source range is
 /// exact the same as \p TargetRange. Returns \c nullptr if not found.
 Expr *findParsedExpr(const DeclContext *DC, SourceRange TargetRange);
diff --git a/lib/IDE/Formatting.cpp b/lib/IDE/Formatting.cpp
index 2f2e80c6def41..cbe1d9ca7422a 100644
--- a/lib/IDE/Formatting.cpp
+++ b/lib/IDE/Formatting.cpp
@@ -587,15 +587,6 @@ class RangeWalker: protected ASTWalker {
   }
 
   PreWalkResult<Expr *> walkToExprPre(Expr *E) override {
-    // Walk through error expressions.
-    if (auto *EE = dyn_cast<ErrorExpr>(E)) {
-      if (auto *OE = EE->getOriginalExpr()) {
-        llvm::SaveAndRestore<ASTWalker::ParentTy>(Parent, EE);
-        OE->walk(*this);
-      }
-      return Action::Continue(E);
-    }
-
     if (E->isImplicit())
       return Action::Continue(E);
 
@@ -1491,17 +1482,6 @@ class FormatWalker : public ASTWalker {
       }
     }
 
-    // Walk through error expressions.
-    if (auto *EE = dyn_cast<ErrorExpr>(E)) {
-      if (Action.shouldVisitChildren()) {
-        if (auto *OE = EE->getOriginalExpr()) {
-          llvm::SaveAndRestore<ASTWalker::ParentTy>(Parent, EE);
-          OE->walk(*this);
-        }
-        return Action::SkipNode(E);
-      }
-    }
-
     // FIXME: We ought to be able to use Action::VisitChildrenIf here, but we'd
     // need to ensure the AST is walked in source order (currently not the case
     // for things like postfix operators).
diff --git a/lib/IDE/IDEBridging.cpp b/lib/IDE/IDEBridging.cpp
index f1b5b58f272bf..373ce88af37b1 100644
--- a/lib/IDE/IDEBridging.cpp
+++ b/lib/IDE/IDEBridging.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022 - 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2022 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -25,13 +25,13 @@ ResolvedLoc::ResolvedLoc(swift::CharSourceRange range,
 
 ResolvedLoc::ResolvedLoc() {}
 
-BridgedResolvedLoc::BridgedResolvedLoc(BridgedCharSourceRange range,
+BridgedResolvedLoc::BridgedResolvedLoc(swift::CharSourceRange range,
                                        BridgedCharSourceRangeVector labelRanges,
                                        unsigned firstTrailingLabel,
                                        LabelRangeType labelType, bool isActive,
                                        ResolvedLocContext context)
     : resolvedLoc(
-          new ResolvedLoc(range.unbridged(), labelRanges.takeUnbridged(),
+          new ResolvedLoc(range, labelRanges.takeUnbridged(),
                           firstTrailingLabel == UINT_MAX
                               ? std::nullopt
                               : std::optional<unsigned>(firstTrailingLabel),
diff --git a/lib/IDE/IDERequests.cpp b/lib/IDE/IDERequests.cpp
index 38a7f73d46672..24a33467ace4a 100644
--- a/lib/IDE/IDERequests.cpp
+++ b/lib/IDE/IDERequests.cpp
@@ -89,8 +89,8 @@ class CursorInfoResolver : public SourceEntityWalker {
   bool walkToDeclPost(Decl *D) override;
   bool walkToStmtPre(Stmt *S) override;
   bool walkToStmtPost(Stmt *S) override;
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type T,
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type T,
                           ReferenceMetaData Data) override;
   bool visitCallArgName(Identifier Name, CharSourceRange Range,
                         ValueDecl *D) override;
@@ -105,7 +105,7 @@ class CursorInfoResolver : public SourceEntityWalker {
                   std::optional<ReferenceMetaData> Data = std::nullopt);
   bool tryResolve(ModuleEntity Mod, SourceLoc Loc);
   bool tryResolve(Stmt *St);
-  bool visitSubscriptReference(ValueDecl *D, CharSourceRange Range,
+  bool visitSubscriptReference(ValueDecl *D, SourceRange Range,
                                ReferenceMetaData Data,
                                bool IsOpenBracket) override;
 };
@@ -210,7 +210,7 @@ bool CursorInfoResolver::tryResolve(Stmt *St) {
 }
 
 bool CursorInfoResolver::visitSubscriptReference(ValueDecl *D,
-                                                 CharSourceRange Range,
+                                                 SourceRange Range,
                                                  ReferenceMetaData Data,
                                                  bool IsOpenBracket) {
   // We should treat both open and close brackets equally
@@ -301,8 +301,7 @@ bool CursorInfoResolver::walkToStmtPost(Stmt *S) {
   return true;
 }
 
-bool CursorInfoResolver::visitDeclReference(ValueDecl *D,
-                                            CharSourceRange Range,
+bool CursorInfoResolver::visitDeclReference(ValueDecl *D, SourceRange Range,
                                             TypeDecl *CtorTyRef,
                                             ExtensionDecl *ExtTyRef, Type T,
                                             ReferenceMetaData Data) {
@@ -310,7 +309,8 @@ bool CursorInfoResolver::visitDeclReference(ValueDecl *D,
     return false;
   if (Data.isImplicit || !Range.isValid())
     return true;
-  return !tryResolve(D, CtorTyRef, ExtTyRef, Range.getStart(), /*IsRef=*/true, T, Data);
+  return !tryResolve(D, CtorTyRef, ExtTyRef, Range.Start, /*IsRef=*/true, T,
+                     Data);
 }
 
 static bool isCursorOn(Expr *E, SourceLoc Loc) {
@@ -461,8 +461,8 @@ class RangeResolver : public SourceEntityWalker {
   bool walkToStmtPost(Stmt *S) override;
   bool walkToDeclPre(Decl *D, CharSourceRange Range) override;
   bool walkToDeclPost(Decl *D) override;
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type T,
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type T,
                           ReferenceMetaData Data) override;
   ResolvedRangeInfo moveArrayToASTContext(ResolvedRangeInfo Info);
 public:
@@ -596,13 +596,13 @@ struct RangeResolver::Implementation {
 
         // For a single expression, its type is apparent.
       case RangeKind::SingleExpression:
-        return {N.get<Expr*>()->getType().getPointer(), ExitState::Negative};
+        return {cast<Expr *>(N)->getType().getPointer(), ExitState::Negative};
 
         // For statements, we either resolve to the returning type or Void.
       case RangeKind::SingleStatement:
       case RangeKind::MultiStatement: {
-        if (N.is<Stmt*>()) {
-          if (auto RS = dyn_cast<ReturnStmt>(N.get<Stmt*>())) {
+        if (isa<Stmt *>(N)) {
+          if (auto RS = dyn_cast<ReturnStmt>(cast<Stmt *>(N))) {
             return {
               resolveNodeType(RS->hasResult() ? RS->getResult() : nullptr,
                               RangeKind::SingleExpression).ReturnType,
@@ -610,7 +610,7 @@ struct RangeResolver::Implementation {
           }
 
           // Unbox the brace statement to find its type.
-          if (auto BS = dyn_cast<BraceStmt>(N.get<Stmt*>())) {
+          if (auto BS = dyn_cast<BraceStmt>(cast<Stmt *>(N))) {
             if (!BS->getElements().empty()) {
               return resolveNodeType(BS->getLastElement(),
                                      RangeKind::SingleStatement);
@@ -618,7 +618,7 @@ struct RangeResolver::Implementation {
           }
 
           // Unbox the if statement to find its type.
-          if (auto *IS = dyn_cast<IfStmt>(N.get<Stmt*>())) {
+          if (auto *IS = dyn_cast<IfStmt>(cast<Stmt *>(N))) {
             llvm::SmallVector<ReturnInfo, 2> Branches;
             Branches.push_back(resolveNodeType(IS->getThenStmt(),
                                                RangeKind::SingleStatement));
@@ -628,7 +628,7 @@ struct RangeResolver::Implementation {
           }
 
           // Unbox switch statement to find return information.
-          if (auto *SWS = dyn_cast<SwitchStmt>(N.get<Stmt*>())) {
+          if (auto *SWS = dyn_cast<SwitchStmt>(cast<Stmt *>(N))) {
             llvm::SmallVector<ReturnInfo, 4> Branches;
             for (auto *CS : SWS->getCases()) {
               Branches.push_back(resolveNodeType(CS->getBody(),
@@ -651,7 +651,7 @@ struct RangeResolver::Implementation {
     bool SingleEntry = true;
     auto UnhandledEffects = getUnhandledEffects({Node});
     OrphanKind Kind = getOrphanKind(ContainedASTNodes);
-    if (Node.is<Expr*>())
+    if (isa<Expr *>(Node))
       return ResolvedRangeInfo(
           RangeKind::SingleExpression,
           resolveNodeType(Node, RangeKind::SingleExpression), TokensInRange,
@@ -659,7 +659,7 @@ struct RangeResolver::Implementation {
           /*Common Parent Expr*/ nullptr, SingleEntry, UnhandledEffects, Kind,
           llvm::ArrayRef(ContainedASTNodes), llvm::ArrayRef(DeclaredDecls),
           llvm::ArrayRef(ReferencedDecls));
-    else if (Node.is<Stmt*>())
+    else if (isa<Stmt *>(Node))
       return ResolvedRangeInfo(
           RangeKind::SingleStatement,
           resolveNodeType(Node, RangeKind::SingleStatement), TokensInRange,
@@ -668,7 +668,7 @@ struct RangeResolver::Implementation {
           llvm::ArrayRef(ContainedASTNodes), llvm::ArrayRef(DeclaredDecls),
           llvm::ArrayRef(ReferencedDecls));
     else {
-      assert(Node.is<Decl*>());
+      assert(isa<Decl *>(Node));
       return ResolvedRangeInfo(
           RangeKind::SingleDecl, ReturnInfo(), TokensInRange,
           getImmediateContext(),
@@ -724,7 +724,7 @@ struct RangeResolver::Implementation {
 
   void leave(ASTNode Node) {
     if (!hasResult() && !Node.isImplicit() && nodeContainSelection(Node)) {
-      if (auto Parent = Node.is<Expr*>() ? Node.get<Expr*>() : nullptr) {
+      if (auto Parent = isa<Expr *>(Node) ? cast<Expr *>(Node) : nullptr) {
         Result = {RangeKind::PartOfExpression,
                   ReturnInfo(),
                   TokensInRange,
@@ -799,12 +799,13 @@ struct RangeResolver::Implementation {
       Impl->analyzeDecl(D);
       return true;
     }
-    bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                            TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type T,
-                            ReferenceMetaData Data) override {
-      Impl->analyzeDeclRef(D, Range.getStart(), T, Data);
+    bool visitDeclReference(ValueDecl *D, SourceRange Range,
+                            TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef,
+                            Type T, ReferenceMetaData Data) override {
+      Impl->analyzeDeclRef(D, Range.Start, T, Data);
       return true;
     }
+
   public:
     CompleteWalker(Implementation *Impl) : Impl(Impl) {}
   };
@@ -813,11 +814,11 @@ struct RangeResolver::Implementation {
   /// decls in the range is referenced after it.
   class FurtherReferenceWalker : public SourceEntityWalker {
     Implementation *Impl;
-    bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                            TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type T,
-                            ReferenceMetaData Data) override {
+    bool visitDeclReference(ValueDecl *D, SourceRange Range,
+                            TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef,
+                            Type T, ReferenceMetaData Data) override {
       // If the reference is after the given range, continue logic.
-      if (!Impl->SM.isBeforeInBuffer(Impl->End, Range.getStart()))
+      if (!Impl->SM.isBeforeInBuffer(Impl->End, Range.Start))
         return true;
 
       // If the referenced decl is declared in the range, than the declared decl
@@ -829,6 +830,7 @@ struct RangeResolver::Implementation {
       }
       return true;
     }
+
   public:
     FurtherReferenceWalker(Implementation *Impl) : Impl(Impl) {}
   };
@@ -846,7 +848,7 @@ struct RangeResolver::Implementation {
     unsigned CaseCount = 0;
     // Count the number of case/default statements.
     for (auto N : Nodes) {
-      if (Stmt *S = N.is<Stmt*>() ? N.get<Stmt*>() : nullptr) {
+      if (Stmt *S = isa<Stmt *>(N) ? cast<Stmt *>(N) : nullptr) {
         if (S->getKind() == StmtKind::Case)
           ++CaseCount;
       }
@@ -899,7 +901,7 @@ struct RangeResolver::Implementation {
   void analyze(ASTNode Node) {
     if (!shouldAnalyze(Node))
       return;
-    Decl *D = Node.is<Decl*>() ? Node.get<Decl*>() : nullptr;
+    Decl *D = isa<Decl *>(Node) ? cast<Decl *>(Node) : nullptr;
     analyzeDecl(D);
     auto &DCInfo = getCurrentDC();
 
@@ -1140,11 +1142,11 @@ bool RangeResolver::walkToDeclPost(Decl *D) {
   return !Impl->hasResult();
 }
 
-
-bool RangeResolver::
-visitDeclReference(ValueDecl *D, CharSourceRange Range, TypeDecl *CtorTyRef,
-                   ExtensionDecl *ExtTyRef, Type T, ReferenceMetaData Data) {
-  Impl->analyzeDeclRef(D, Range.getStart(), T, Data);
+bool RangeResolver::visitDeclReference(ValueDecl *D, SourceRange Range,
+                                       TypeDecl *CtorTyRef,
+                                       ExtensionDecl *ExtTyRef, Type T,
+                                       ReferenceMetaData Data) {
+  Impl->analyzeDeclRef(D, Range.Start, T, Data);
   return true;
 }
 
diff --git a/lib/IDE/IDETypeChecking.cpp b/lib/IDE/IDETypeChecking.cpp
index abbc2ae8ca010..e6c184ee99274 100644
--- a/lib/IDE/IDETypeChecking.cpp
+++ b/lib/IDE/IDETypeChecking.cpp
@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/Sema/IDETypeChecking.h"
+#include "ReadyForTypeCheckingCallback.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTDemangler.h"
 #include "swift/AST/ASTPrinter.h"
@@ -32,9 +33,11 @@
 #include "swift/IDE/SourceEntityWalker.h"
 #include "swift/Parse/Lexer.h"
 #include "swift/Sema/IDETypeCheckingRequests.h"
+#include "swift/Subsystems.h"
 #include "llvm/ADT/SmallVector.h"
 
 using namespace swift;
+using namespace ide;
 
 void swift::getTopLevelDeclsForDisplay(ModuleDecl *M,
                                        SmallVectorImpl<Decl *> &Results,
@@ -277,22 +280,17 @@ struct SynthesizedExtensionAnalyzer::Implementation {
   using MergeGroupVector = std::vector<ExtensionMergeGroup>;
 
   NominalTypeDecl *Target;
-  Type BaseType;
   DeclContext *DC;
   bool IncludeUnconditional;
   PrintOptions Options;
   MergeGroupVector AllGroups;
   ExtensionInfoMap InfoMap;
 
-  Implementation(NominalTypeDecl *Target,
-                 bool IncludeUnconditional,
-                 PrintOptions Options):
-  Target(Target),
-  BaseType(Target->getDeclaredInterfaceType()),
-  DC(Target),
-  IncludeUnconditional(IncludeUnconditional),
-  Options(Options), AllGroups(MergeGroupVector()),
-  InfoMap(collectSynthesizedExtensionInfo(AllGroups)) {}
+  Implementation(NominalTypeDecl *Target, bool IncludeUnconditional,
+                 PrintOptions &&Options)
+      : Target(Target), DC(Target), IncludeUnconditional(IncludeUnconditional),
+        Options(std::move(Options)), AllGroups(MergeGroupVector()),
+        InfoMap(collectSynthesizedExtensionInfo(AllGroups)) {}
 
   unsigned countInherits(ExtensionDecl *ED) {
     SmallVector<InheritedEntry, 4> Results;
@@ -316,19 +314,24 @@ struct SynthesizedExtensionAnalyzer::Implementation {
     // extension SomeType: SomeProtocol where T: SomeProtocol {}. The former is
     // Ext and the latter is EnablingExt/Conf. Either of these can be
     // conditional in ways that need to be considered when merging.
-    auto conformanceIsConditional =
-        Conf && !Conf->getConditionalRequirements().empty();
-    if (!Ext->isConstrainedExtension() && !conformanceIsConditional) {
+    auto isConditionalEnablingExt =
+        Conf && EnablingExt && !Conf->getConditionalRequirements().empty();
+    if (!Ext->isConstrainedExtension() && !isConditionalEnablingExt) {
       if (IncludeUnconditional)
         Result.Ext = Ext;
       return {Result, MergeInfo};
     }
 
-    auto handleRequirements = [&](SubstitutionMap subMap,
-                                  ExtensionDecl *OwningExt,
+    auto handleRequirements = [&](ExtensionDecl *OwningExt,
                                   ArrayRef<Requirement> Reqs) {
-      ProtocolDecl *BaseProto = OwningExt->getInnermostDeclContext()
-        ->getSelfProtocolDecl();
+      ProtocolDecl *BaseProto = OwningExt->getSelfProtocolDecl();
+      // Substitute the base conforming type into a protocol's generic signature
+      // if needed.
+      SubstitutionMap subMap;
+      if (Conf && BaseProto) {
+        subMap = SubstitutionMap::getProtocolSubstitutions(
+            ProtocolConformanceRef(Conf));
+      }
       for (auto Req : Reqs) {
         // Skip protocol's Self : <Protocol> requirement.
         if (BaseProto &&
@@ -337,10 +340,13 @@ struct SynthesizedExtensionAnalyzer::Implementation {
             Req.getProtocolDecl() == BaseProto)
           continue;
 
-        if (!BaseType->isExistentialType()) {
+        if (subMap) {
           // Apply any substitutions we need to map the requirements from a
-          // a protocol extension to an extension on the conforming type.
-          Req = Req.subst(subMap);
+          // a protocol extension to an extension on the conforming type. We
+          // need to lookup conformances outside of the substitution map since
+          // the extension may introduce new conformance constraints.
+          Req = Req.subst(QuerySubstitutionMap{subMap},
+                          LookUpConformanceInModule());
           if (Req.hasError()) {
             // Substitution with interface type bases can only fail
             // if a concrete type fails to conform to a protocol.
@@ -353,6 +359,14 @@ struct SynthesizedExtensionAnalyzer::Implementation {
         if (Req.getKind() != RequirementKind::Layout)
           assert(!Req.getSecondType()->hasArchetype());
 
+        // FIXME: This doesn't correctly handle conformance requirements, e.g:
+        //
+        // extension P where X: Q, X.Y == Int {}
+        //
+        // Since the archetype we have for `X` doesn't necessarily have a
+        // conformance to `Q` in the conforming type's generic environment. This
+        // results in a substitution failure for `X.Y`.
+        // https://github.com/swiftlang/swift/issues/83564
         auto *env = Target->getGenericEnvironment();
         SmallVector<Requirement, 2> subReqs;
         subReqs.push_back(
@@ -385,30 +399,14 @@ struct SynthesizedExtensionAnalyzer::Implementation {
     };
 
     if (Ext->isConstrainedExtension()) {
-      // Get the substitutions from the generic signature of
-      // the extension to the interface types of the base type's
-      // declaration.
-      SubstitutionMap subMap;
-      if (!BaseType->isExistentialType()) {
-        if (auto *NTD = Ext->getExtendedNominal())
-          subMap = BaseType->getContextSubstitutionMap(NTD);
-      }
-
       assert(Ext->getGenericSignature() && "No generic signature.");
       auto GenericSig = Ext->getGenericSignature();
-      if (handleRequirements(subMap, Ext, GenericSig.getRequirements()))
+      if (handleRequirements(Ext, GenericSig.getRequirements()))
         return {Result, MergeInfo};
     }
 
-    if (Conf) {
-      SubstitutionMap subMap;
-      if (!BaseType->isExistentialType()) {
-        if (auto *NTD = EnablingExt->getExtendedNominal())
-          subMap = BaseType->getContextSubstitutionMap(NTD);
-      }
-      if (handleRequirements(subMap,
-                             EnablingExt,
-                             Conf->getConditionalRequirements()))
+    if (isConditionalEnablingExt) {
+      if (handleRequirements(EnablingExt, Conf->getConditionalRequirements()))
         return {Result, MergeInfo};
     }
 
@@ -479,19 +477,18 @@ struct SynthesizedExtensionAnalyzer::Implementation {
 
     ExtensionInfoMap InfoMap;
     ExtensionMergeInfoMap MergeInfoMap;
-    std::vector<NominalTypeDecl*> Unhandled;
 
     auto handleExtension = [&](ExtensionDecl *E, bool Synthesized,
                                ExtensionDecl *EnablingE,
                                NormalProtocolConformance *Conf) {
-      PrintOptions AdjustedOpts = Options;
+      PrintOptions::OverrideScope AdjustedOpts(Options);
       if (Synthesized) {
         // Members from underscored system protocols should still appear as
         // members of the target type, even if the protocols themselves are not
         // printed.
-        AdjustedOpts.SkipUnderscoredSystemProtocols = false;
+        OVERRIDE_PRINT_OPTION(AdjustedOpts, SkipUnderscoredSystemProtocols, false);
       }
-      if (AdjustedOpts.shouldPrint(E)) {
+      if (Options.shouldPrint(E)) {
         auto Pair = isApplicable(E, Synthesized, EnablingE, Conf);
         if (Pair.first) {
           InfoMap.insert({E, Pair.first});
@@ -500,31 +497,17 @@ struct SynthesizedExtensionAnalyzer::Implementation {
       }
     };
 
-    // We want to visit the protocols of any normal conformances we see, but
-    // we have to avoid doing this to self-conformances or we can end up with
-    // a cycle.  Otherwise this is cycle-proof on valid code.
-    // We also want to ignore inherited conformances. Members from these will
-    // be included in the class they were inherited from.
-    auto addConformance = [&](ProtocolConformance *Conf) {
-      if (isa<InheritedProtocolConformance>(Conf))
-        return;
-      auto RootConf = Conf->getRootConformance();
-      if (isa<NormalProtocolConformance>(RootConf))
-        Unhandled.push_back(RootConf->getProtocol());
-    };
+    for (auto *LocalConf : Target->getLocalConformances()) {
+      if (isa<InheritedProtocolConformance>(LocalConf))
+        continue;
 
-    for (auto *Conf : Target->getLocalConformances()) {
-      addConformance(Conf);
-    }
-    while (!Unhandled.empty()) {
-      NominalTypeDecl* Back = Unhandled.back();
-      Unhandled.pop_back();
-      for (ExtensionDecl *E : Back->getExtensions()) {
-        handleExtension(E, true, nullptr, nullptr);
-      }
-      for (auto *Conf : Back->getLocalConformances()) {
-        addConformance(Conf);
-      }
+      auto RootConf = LocalConf->getRootConformance();
+      auto *Conf = dyn_cast<NormalProtocolConformance>(RootConf);
+      if (!Conf)
+        continue;
+
+      for (auto *E : Conf->getProtocol()->getExtensions())
+        handleExtension(E, true, nullptr, Conf);
     }
 
     // Merge with actual extensions.
@@ -556,8 +539,8 @@ struct SynthesizedExtensionAnalyzer::Implementation {
 };
 
 SynthesizedExtensionAnalyzer::SynthesizedExtensionAnalyzer(
-    NominalTypeDecl *Target, PrintOptions Options, bool IncludeUnconditional)
-    : Impl(*(new Implementation(Target, IncludeUnconditional, Options))) {}
+    NominalTypeDecl *Target, PrintOptions &&Options, bool IncludeUnconditional)
+    : Impl(*(new Implementation(Target, IncludeUnconditional, std::move(Options)))) {}
 
 SynthesizedExtensionAnalyzer::~SynthesizedExtensionAnalyzer() {delete &Impl;}
 
@@ -1048,3 +1031,11 @@ swift::getShorthandShadows(LabeledConditionalStmt *CondStmt, DeclContext *DC) {
   }
   return Result;
 }
+
+void ReadyForTypeCheckingCallback::doneParsing(SourceFile *SrcFile) {
+  // Import resolution will have already been done by IDEInspectionInstance,
+  // we need to bind extensions here though since IDEInspectionSecondPassRequest
+  // can mutate the AST.
+  bindExtensions(*SrcFile->getParentModule());
+  readyForTypeChecking(SrcFile);
+}
diff --git a/lib/IDE/ModuleInterfacePrinting.cpp b/lib/IDE/ModuleInterfacePrinting.cpp
index b7a634d88dfc6..53671c7b65fba 100644
--- a/lib/IDE/ModuleInterfacePrinting.cpp
+++ b/lib/IDE/ModuleInterfacePrinting.cpp
@@ -94,15 +94,15 @@ printTypeInterface(ModuleDecl *M, StringRef TypeUSR, ASTPrinter &Printer,
                             Printer, TypeName, Error);
 }
 
-static void adjustPrintOptions(PrintOptions &AdjustedOptions) {
+static void adjustPrintOptions(PrintOptions::OverrideScope &Options) {
   // Don't print empty curly braces while printing the module interface.
-  AdjustedOptions.FunctionDefinitions = false;
+  OVERRIDE_PRINT_OPTION(Options, FunctionDefinitions, false);
 
-  AdjustedOptions.PrintGetSetOnRWProperties = false;
+  OVERRIDE_PRINT_OPTION(Options, PrintGetSetOnRWProperties, false);
 
   // Print var declarations separately, one variable per decl.
-  AdjustedOptions.ExplodePatternBindingDecls = true;
-  AdjustedOptions.VarInitializers = false;
+  OVERRIDE_PRINT_OPTION(Options, ExplodePatternBindingDecls, true);
+  OVERRIDE_PRINT_OPTION(Options, VarInitializers, false);
 }
 
 void swift::ide::collectModuleGroups(ModuleDecl *M,
@@ -138,7 +138,7 @@ std::optional<StringRef> swift::ide::findGroupNameForUSR(ModuleDecl *M,
 /// \returns Whether the given decl was printed.
 static bool printModuleInterfaceDecl(Decl *D,
                                      ASTPrinter &Printer,
-                                     PrintOptions &Options,
+                                     const PrintOptions &Options,
                                      bool PrintSynthesizedExtensions,
                                      StringRef LeadingComment = StringRef()) {
   if (!Options.shouldPrint(D)) {
@@ -156,16 +156,27 @@ static bool printModuleInterfaceDecl(Decl *D,
         return false;
     }
   }
+
+  // It'd be nice to avoid cloning the options here, but that would require
+  // SynthesizedExtensionAnalyzer to promise to stay within the lifetime of
+  // the options it was constructed with, and besides, it isn't easy to see
+  // whether the mutations we make to Options here are meant to be independent
+  // of what might be done with the analyzer.
+  PrintOptions::OverrideScope OptionAdjustment(Options);
+
   std::unique_ptr<SynthesizedExtensionAnalyzer> pAnalyzer;
   if (auto NTD = dyn_cast<NominalTypeDecl>(D)) {
     if (PrintSynthesizedExtensions) {
-      pAnalyzer.reset(new SynthesizedExtensionAnalyzer(NTD, Options));
-      Options.BracketOptions = {
+      pAnalyzer.reset(new SynthesizedExtensionAnalyzer(NTD, Options.clone()));
+
+      BracketOptions NewBracketOptions = {
         NTD, true, true,
         !pAnalyzer->hasMergeGroup(
           SynthesizedExtensionAnalyzer::MergeGroupKind::MergeableWithTypeDef
         )
       };
+      OVERRIDE_PRINT_OPTION_UNCONDITIONAL(OptionAdjustment, BracketOptions,
+                                          NewBracketOptions);
     }
   }
   if (!LeadingComment.empty() && Options.shouldPrint(D)) {
@@ -175,7 +186,8 @@ static bool printModuleInterfaceDecl(Decl *D,
   if (D->print(Printer, Options)) {
     if (Options.BracketOptions.shouldCloseNominal(D))
       Printer.printNewline();
-    Options.BracketOptions = BracketOptions();
+    OVERRIDE_PRINT_OPTION_UNCONDITIONAL(OptionAdjustment, BracketOptions,
+                                        BracketOptions());
     if (auto NTD = dyn_cast<NominalTypeDecl>(D)) {
       std::queue<NominalTypeDecl *> SubDecls{{NTD}};
 
@@ -222,15 +234,18 @@ static bool printModuleInterfaceDecl(Decl *D,
             SynthesizedExtensionAnalyzer::MergeGroupKind::MergeableWithTypeDef,
             [&](ArrayRef<ExtensionInfo> Decls) {
               for (auto ET : Decls) {
-                Options.BracketOptions = {
+                PrintOptions::OverrideScope ETOptionsScope(Options);
+
+                BracketOptions NewBracketOptions = {
                   ET.Ext, false, Decls.back().Ext == ET.Ext, true
                 };
+                OVERRIDE_PRINT_OPTION_UNCONDITIONAL(ETOptionsScope, BracketOptions,
+                                                    NewBracketOptions);
+
                 if (ET.IsSynthesized)
-                  Options.initForSynthesizedExtension(NTD);
+                  Options.initForSynthesizedExtensionInScope(NTD, ETOptionsScope);
                 ET.Ext->print(Printer, Options);
-                if (ET.IsSynthesized)
-                  Options.clearSynthesizedExtension();
-                if (Options.BracketOptions.shouldCloseExtension(ET.Ext))
+                if (NewBracketOptions.shouldCloseExtension(ET.Ext))
                   Printer.printNewline();
               }
             });
@@ -238,7 +253,7 @@ static bool printModuleInterfaceDecl(Decl *D,
 
         // If the printed Decl is not the top-level one, reset analyzer.
         if (!IsTopLevelDecl)
-          pAnalyzer.reset(new SynthesizedExtensionAnalyzer(NTD, Options));
+          pAnalyzer.reset(new SynthesizedExtensionAnalyzer(NTD, Options.clone()));
 
         // Print the rest as synthesized extensions.
         pAnalyzer->forEachExtensionMergeGroup(
@@ -251,10 +266,15 @@ static bool printModuleInterfaceDecl(Decl *D,
             // Whether we've started the extension merge group in printing.
             bool Opened = false;
             for (auto ET : Decls) {
-              Options.BracketOptions = {
+              PrintOptions::OverrideScope ETOptionsScope(Options);
+
+              BracketOptions NewBracketOptions = {
                 ET.Ext, !Opened, Decls.back().Ext == ET.Ext, true
               };
-              if (Options.BracketOptions.shouldOpenExtension(ET.Ext)) {
+              OVERRIDE_PRINT_OPTION_UNCONDITIONAL(ETOptionsScope, BracketOptions,
+                                                  NewBracketOptions);
+
+              if (NewBracketOptions.shouldOpenExtension(ET.Ext)) {
                 Printer.printNewline();
                 if (Options.shouldPrint(ET.Ext) && !LeadingComment.empty()) {
                   Printer << LeadingComment;
@@ -263,20 +283,19 @@ static bool printModuleInterfaceDecl(Decl *D,
               }
               if (ET.IsSynthesized) {
                 if (ET.EnablingExt)
-                  Options.initForSynthesizedExtension(ET.EnablingExt);
+                  Options.initForSynthesizedExtensionInScope(ET.EnablingExt,
+                                                             ETOptionsScope);
                 else
-                  Options.initForSynthesizedExtension(NTD);
+                  Options.initForSynthesizedExtensionInScope(NTD, ETOptionsScope);
               }
               // Set opened if we actually printed this extension.
               Opened |= ET.Ext->print(Printer, Options);
-              if (ET.IsSynthesized)
-                Options.clearSynthesizedExtension();
-              if (Options.BracketOptions.shouldCloseExtension(ET.Ext)) {
+
+              if (NewBracketOptions.shouldCloseExtension(ET.Ext)) {
                 Printer.printNewline();
               }
             }
           });
-        Options.BracketOptions = BracketOptions();
       }
     }
     return true;
@@ -304,6 +323,34 @@ static bool compareSwiftDecls(Decl *LHS, Decl *RHS) {
   return LHS->getKind() < RHS->getKind();
 }
 
+static bool shouldPrintImport(ImportDecl *ImportD, ModuleDecl *OrigMod,
+                              const clang::Module *OrigClangMod) {
+  if (ImportD->getAttrs().hasAttribute<ImplementationOnlyAttr>())
+    return false;
+
+  auto *ImportedMod = ImportD->getModule();
+  if (ImportedMod) {
+    if (ImportedMod == OrigMod)
+      return false;
+    if (ImportedMod->isOnoneSupportModule())
+      return false;
+    if (ImportedMod->getName().hasUnderscoredNaming())
+      return false;
+  }
+
+  if (!OrigClangMod)
+    return true;
+
+  auto ImportedClangMod = ImportD->getClangModule();
+  if (!ImportedClangMod)
+    return true;
+  if (!ImportedClangMod->isSubModule())
+    return true;
+  if (ImportedClangMod == OrigClangMod)
+    return false;
+  return ImportedClangMod->isSubModuleOf(OrigClangMod);
+}
+
 static std::pair<ArrayRef<Decl*>, ArrayRef<Decl*>>
 getDeclsFromCrossImportOverlay(ModuleDecl *Overlay, ModuleDecl *Declaring,
                                SmallVectorImpl<Decl *> &Decls,
@@ -329,7 +376,8 @@ getDeclsFromCrossImportOverlay(ModuleDecl *Overlay, ModuleDecl *Declaring,
 
       // Ignore imports of the underlying module, or any cross-import
       // that would map back to it.
-      if (Imported == Declaring || Imported->isCrossImportOverlayOf(Declaring))
+      if (!shouldPrintImport(ID, Declaring, nullptr) ||
+          Imported->isCrossImportOverlayOf(Declaring))
         return false;
 
       // Ignore an imports of modules also imported by the underlying module.
@@ -366,7 +414,7 @@ getDeclsFromCrossImportOverlay(ModuleDecl *Overlay, ModuleDecl *Declaring,
 
 static void printCrossImportOverlays(ModuleDecl *Declaring, ASTContext &Ctx,
                                      ASTPrinter &Printer,
-                                     PrintOptions Options,
+                                     const PrintOptions &Options,
                                      bool PrintSynthesizedExtensions) {
   SmallVector<Decl *, 1> OverlayDecls;
   SmallVector<Identifier, 1> Bystanders;
@@ -454,22 +502,43 @@ void swift::ide::printModuleInterface(
   auto &Importer =
       static_cast<ClangImporter &>(*SwiftContext.getClangModuleLoader());
 
-  auto AdjustedOptions = Options;
-  adjustPrintOptions(AdjustedOptions);
+  PrintOptions::OverrideScope OptionAdjustment(Options);
+  adjustPrintOptions(OptionAdjustment);
 
+  llvm::DenseSet<const void *> SeenImportedDecls;
   SmallVector<ModuleDecl *, 1> ModuleList;
   ModuleList.push_back(TargetMod);
+  SeenImportedDecls.insert(TargetMod);
 
-  SmallVector<ImportDecl *, 1> ImportDecls;
-  llvm::DenseSet<const clang::Module *> ClangModulesForImports;
-  SmallVector<Decl *, 1> SwiftDecls;
+  SmallVector<ImportDecl *, 0> ImportDecls;
+  SmallVector<Decl *, 0> SwiftDecls;
   llvm::DenseMap<const clang::Module *,
-                 SmallVector<std::pair<Decl *, clang::SourceLocation>, 1>>
-    ClangDecls;
+                 SmallVector<std::pair<Decl *, clang::SourceLocation>, 0>>
+      ClangDecls;
+
+  // Add exported modules that have the same public module name as this module
+  // (excluding the underlying clang module if there is one).
+  if (TraversalOptions & ModuleTraversal::VisitMatchingExported) {
+    SmallVector<ImportedModule> Imports;
+    TargetMod->getImportedModules(Imports,
+                                  ModuleDecl::ImportFilterKind::Exported);
+    for (ImportedModule Import : Imports) {
+      if (Import.importedModule->getPublicModuleName(
+              /*onlyIfImported=*/false) != TargetMod->getName())
+        continue;
+
+      if (TargetClangMod != nullptr &&
+          Import.importedModule->findUnderlyingClangModule() == TargetClangMod)
+        continue;
+
+      ModuleList.push_back(Import.importedModule);
+      SeenImportedDecls.insert(Import.importedModule);
+    }
+  }
 
-  // If we're printing recursively, find all of the submodules to print.
   if (TargetClangMod) {
-    if (TraversalOptions) {
+    // Add clang submodules if they're being visited
+    if (TraversalOptions & ModuleTraversal::VisitSubmodules) {
       SmallVector<const clang::Module *, 8> Worklist;
       SmallPtrSet<const clang::Module *, 8> Visited;
       Worklist.push_back(TargetClangMod);
@@ -482,16 +551,15 @@ void swift::ide::printModuleInterface(
 
         ClangDecls.insert({ CM, {} });
 
-        if (CM != TargetClangMod)
-          if (auto *OwningModule = Importer.getWrapperForModule(CM))
+        if (CM != TargetClangMod) {
+          if (auto *OwningModule = Importer.getWrapperForModule(CM)) {
             ModuleList.push_back(OwningModule);
+          }
+        }
 
-        // If we're supposed to visit submodules, add them now.
-        if (TraversalOptions & ModuleTraversal::VisitSubmodules) {
-          for (clang::Module * submodule: CM->submodules()) {
-            if (Visited.insert(submodule).second) {
-                Worklist.push_back(submodule);
-            }
+        for (clang::Module *submodule : CM->submodules()) {
+          if (Visited.insert(submodule).second) {
+            Worklist.push_back(submodule);
           }
         }
       }
@@ -500,8 +568,7 @@ void swift::ide::printModuleInterface(
     }
   }
 
-  SmallVector<Decl *, 1> Decls;
-
+  SmallVector<Decl *, 0> Decls;
   for (ModuleDecl *M : ModuleList) {
     swift::getTopLevelDeclsForDisplay(M, Decls);
   }
@@ -527,42 +594,38 @@ void swift::ide::printModuleInterface(
         continue;
     }
 
-    auto ShouldPrintImport = [&](ImportDecl *ImportD) -> bool {
-      if (ImportD->getAttrs().hasAttribute<ImplementationOnlyAttr>())
-        return false;
+    if (auto ID = dyn_cast<ImportDecl>(D)) {
+      if (!shouldPrintImport(ID, TargetMod, TargetClangMod))
+        continue;
 
-      if (!TargetClangMod)
-        return true;
-      if (ImportD->getModule() == TargetMod)
-        return false;
+      // Erase submodules that are not missing
+      if (ID->getClangModule())
+        NoImportSubModules.erase(ID->getClangModule());
 
-      auto ImportedMod = ImportD->getClangModule();
-      if (!ImportedMod)
-        return true;
-      if (!ImportedMod->isSubModule())
-        return true;
-      if (ImportedMod == TargetClangMod)
-        return false;
-      return ImportedMod->isSubModuleOf(TargetClangMod);
-    };
+      if (ID->getImportKind() == ImportKind::Module) {
+        // Could have a duplicate import from a clang module's overlay or
+        // because we're merging modules. Skip them.
 
-    if (auto ID = dyn_cast<ImportDecl>(D)) {
-      if (ShouldPrintImport(ID)) {
-        if (ID->getClangModule())
-          // Erase those submodules that are not missing.
-          NoImportSubModules.erase(ID->getClangModule());
-        if (ID->getImportKind() == ImportKind::Module) {
-          // Make sure we don't print duplicate imports, due to getting imports
-          // for both a clang module and its overlay.
-          if (auto *ClangMod = getUnderlyingClangModuleForImport(ID)) {
-            auto P = ClangModulesForImports.insert(ClangMod);
-            bool IsNew = P.second;
-            if (!IsNew)
-              continue;
-          }
+        if (auto *ClangMod = getUnderlyingClangModuleForImport(ID)) {
+          if (!SeenImportedDecls.insert(ClangMod).second)
+            continue;
+        }
+
+        if (auto *ImportedMod = ID->getModule()) {
+          if (!SeenImportedDecls.insert(ImportedMod).second)
+            continue;
+        }
+      } else {
+        bool AnyNewDecls = false;
+        for (auto *ImportedDecl : ID->getDecls()) {
+          AnyNewDecls |= SeenImportedDecls.insert(ImportedDecl).second;
         }
-        ImportDecls.push_back(ID);
+        if (!AnyNewDecls)
+          continue;
       }
+
+      ImportDecls.push_back(ID);
+
       continue;
     }
 
@@ -678,15 +741,18 @@ void swift::ide::printModuleInterface(
     std::stable_sort(SwiftDecls.begin(), SwiftDecls.end(), compareSwiftDecls);
 
   auto PrintDecl = [&](Decl *D) {
-    return printModuleInterfaceDecl(D, Printer, AdjustedOptions,
+    return printModuleInterfaceDecl(D, Printer, Options,
                                     PrintSynthesizedExtensions);
   };
 
   // Imports from the stdlib are internal details that don't need to be exposed.
   if (!TargetMod->isStdlibModule()) {
-    for (auto *D : ImportDecls)
+    for (auto *D : ImportDecls) {
       PrintDecl(D);
-    Printer.printNewline();
+    }
+    if (!ImportDecls.empty()) {
+      Printer.printNewline();
+    }
   }
 
   {
@@ -720,7 +786,7 @@ void swift::ide::printModuleInterface(
     // is the underlying module of, transitively.
     if (GroupNames.empty()) {
       printCrossImportOverlays(TargetMod, SwiftContext, Printer,
-                               AdjustedOptions, PrintSynthesizedExtensions);
+                               Options, PrintSynthesizedExtensions);
     }
   }
   // Flush pending newlines.
@@ -795,8 +861,8 @@ void swift::ide::printHeaderInterface(
        ASTContext &Ctx,
        ASTPrinter &Printer,
        const PrintOptions &Options) {
-  auto AdjustedOptions = Options;
-  adjustPrintOptions(AdjustedOptions);
+  PrintOptions::OverrideScope OptionAdjustment(Options);
+  adjustPrintOptions(OptionAdjustment);
 
   auto &Importer = static_cast<ClangImporter &>(*Ctx.getClangModuleLoader());
   auto &ClangSM = Importer.getClangASTContext().getSourceManager();
@@ -827,36 +893,12 @@ void swift::ide::printHeaderInterface(
     // equivalent Swift decl may not be. E.g. a top-level function may be mapped
     // to a property accessor in Swift.
     D = getTopLevelDecl(D);
-    if (!AdjustedOptions.shouldPrint(D)) {
+    if (!Options.shouldPrint(D)) {
       Printer.callAvoidPrintDeclPost(D);
       continue;
     }
-    if (D->print(Printer, AdjustedOptions))
+    if (D->print(Printer, Options))
       Printer.printNewline();
   }
   Printer.forceNewlines();
 }
-
-void swift::ide::printSymbolicSwiftClangModuleInterface(
-    ModuleDecl *M, ASTPrinter &Printer, const clang::Module *clangModule) {
-  std::string headerComment;
-  llvm::raw_string_ostream(headerComment)
-      << "// Swift interface for " << (clangModule->IsSystem ? "system " : "")
-      << "module '" << clangModule->Name << "'\n";
-  Printer.printText(headerComment);
-
-  ModuleTraversalOptions opts;
-  opts |= ModuleTraversal::VisitSubmodules;
-  auto popts =
-      PrintOptions::printModuleInterface(/*printFullConvention=*/false);
-  popts.PrintDocumentationComments = false;
-  popts.SkipInlineCXXNamespace = true;
-
-  auto &SwiftContext = M->getTopLevelModule()->getASTContext();
-  auto &Importer =
-      static_cast<ClangImporter &>(*SwiftContext.getClangModuleLoader());
-  Importer.withSymbolicFeatureEnabled([&]() {
-    printModuleInterface(M, {}, opts, Printer, popts,
-                         /*SynthesizeExtensions=*/false);
-  });
-}
diff --git a/lib/IDE/PostfixCompletion.cpp b/lib/IDE/PostfixCompletion.cpp
index 02849e6b72980..b4bcd69679b25 100644
--- a/lib/IDE/PostfixCompletion.cpp
+++ b/lib/IDE/PostfixCompletion.cpp
@@ -10,11 +10,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "swift/Basic/Assertions.h"
 #include "swift/IDE/PostfixCompletion.h"
+#include "swift/Basic/Assertions.h"
 #include "swift/IDE/CodeCompletion.h"
 #include "swift/IDE/CompletionLookup.h"
-#include "swift/Sema/CompletionContextFinder.h"
 #include "swift/Sema/ConstraintSystem.h"
 #include "swift/Sema/IDETypeChecking.h"
 
@@ -27,8 +26,7 @@ bool PostfixCompletionCallback::Result::tryMerge(const Result &Other,
   if (BaseDecl != Other.BaseDecl)
     return false;
 
-  // These properties should match if we are talking about the same BaseDecl.
-  assert(IsBaseDeclUnapplied == Other.IsBaseDeclUnapplied);
+  // This should match if we are talking about the same BaseDecl.
   assert(BaseIsStaticMetaType == Other.BaseIsStaticMetaType);
 
   auto baseTy = tryMergeBaseTypeForCompletionLookup(BaseTy, Other.BaseTy, DC);
@@ -56,6 +54,12 @@ bool PostfixCompletionCallback::Result::tryMerge(const Result &Other,
   ExpectsNonVoid &= Other.ExpectsNonVoid;
   IsImpliedResult |= Other.IsImpliedResult;
   IsInAsyncContext |= Other.IsInAsyncContext;
+
+  // Note this may differ if we pre-check multiple times since pre-checking
+  // changes the recorded apply level.
+  // FIXME: We ought to fix completion to not pre-check multiple times.
+  IsBaseDeclUnapplied |= Other.IsBaseDeclUnapplied;
+
   return true;
 }
 
@@ -67,37 +71,6 @@ void PostfixCompletionCallback::addResult(const Result &Res) {
   Results.push_back(Res);
 }
 
-void PostfixCompletionCallback::fallbackTypeCheck(DeclContext *DC) {
-  assert(!gotCallback());
-
-  // Default to checking the completion expression in isolation.
-  Expr *fallbackExpr = CompletionExpr;
-  DeclContext *fallbackDC = DC;
-
-  auto finder = CompletionContextFinder::forFallback(DC);
-  if (finder.hasCompletionExpr()) {
-    if (auto fallback = finder.getFallbackCompletionExpr()) {
-      fallbackExpr = fallback->E;
-      fallbackDC = fallback->DC;
-    }
-  }
-
-  if (isa<AbstractClosureExpr>(fallbackDC)) {
-    // If the expression is embedded in a closure, the constraint system tries
-    // to retrieve that closure's type, which will fail since we won't have
-    // generated any type variables for it. Thus, fallback type checking isn't
-    // available in this case.
-    return;
-  }
-
-  SyntacticElementTarget completionTarget(fallbackExpr, fallbackDC, CTP_Unused,
-                                          Type(),
-                                          /*isDiscared=*/true);
-
-  typeCheckForCodeCompletion(completionTarget, /*needsPrecheck*/ true,
-                             [&](const Solution &S) { sawSolution(S); });
-}
-
 static ActorIsolation
 getClosureActorIsolation(const Solution &S, AbstractClosureExpr *ACE) {
   auto getType = [&S](Expr *E) -> Type {
@@ -110,9 +83,6 @@ getClosureActorIsolation(const Solution &S, AbstractClosureExpr *ACE) {
       if (auto Ty = target->getClosureContextualType())
         return Ty;
     }
-    if (!S.hasType(E)) {
-      return Type();
-    }
     return getTypeForCompletion(S, E);
   };
   auto getClosureActorIsolationThunk = [&S](AbstractClosureExpr *ACE) {
@@ -122,25 +92,26 @@ getClosureActorIsolation(const Solution &S, AbstractClosureExpr *ACE) {
                                         getClosureActorIsolationThunk);
 }
 
-/// Returns \c true if \p Choice refers to a function that hasn't been called
-/// yet.
-static bool isUnappliedFunctionRef(const OverloadChoice &Choice) {
-  if (!Choice.isDecl()) {
+/// Returns \c true if \p Choice refers to a function that has been fully
+/// applied, including the curried self if present.
+static bool isFullyAppliedFunctionRef(const Solution &S,
+                                      const OverloadChoice &Choice) {
+  auto *D = Choice.getDeclOrNull();
+  if (!D)
     return false;
-  }
-  auto fnRefKind = Choice.getFunctionRefInfo();
 
-  if (fnRefKind.isUnapplied())
+  switch (Choice.getFunctionRefInfo().getApplyLevel()) {
+  case FunctionRefInfo::ApplyLevel::Unapplied:
+    // No argument lists have been applied.
+    return false;
+  case FunctionRefInfo::ApplyLevel::SingleApply:
+    // The arguments have been applied, check to see if the curried self has
+    // been applied if present.
+    return !D->hasCurriedSelf() || hasAppliedSelf(S, Choice);
+  case FunctionRefInfo::ApplyLevel::DoubleApply:
+    // All argument lists have been applied.
     return true;
-
-  // We consider curried member calls as unapplied. E.g.
-  //   MyStruct.someInstanceFunc(theInstance)#^COMPLETE^#
-  // is unapplied.
-  if (fnRefKind.isSingleApply()) {
-    if (auto BaseTy = Choice.getBaseType())
-      return BaseTy->is<MetatypeType>() && !Choice.getDeclOrNull()->isStatic();
   }
-  return false;
 }
 
 void PostfixCompletionCallback::sawSolutionImpl(
@@ -169,7 +140,8 @@ void PostfixCompletionCallback::sawSolutionImpl(
   bool IsBaseDeclUnapplied = false;
   if (auto SelectedOverload = S.getOverloadChoiceIfAvailable(CalleeLocator)) {
     ReferencedDecl = SelectedOverload->choice.getDeclOrNull();
-    IsBaseDeclUnapplied = isUnappliedFunctionRef(SelectedOverload->choice);
+    IsBaseDeclUnapplied = ReferencedDecl && !isFullyAppliedFunctionRef(
+                                                S, SelectedOverload->choice);
   }
 
   bool BaseIsStaticMetaType = S.isStaticallyDerivedMetatype(ParsedExpr);
@@ -448,7 +420,7 @@ void PostfixCompletionCallback::collectResults(
     // tuple. But that doesn’t really make sense so we shouldn't be suggesting
     // any operators based on `Void`.
     if (IncludeOperators && !Result.BaseIsStaticMetaType &&
-        !Result.BaseTy->isVoid() &&
+        !Result.BaseTy->isVoid() && !Result.BaseTy->hasError() &&
         !ProcessedBaseTypes.contains(Result.BaseTy)) {
       addOperatorResults(Result.BaseTy, Operators, DC, Lookup);
     }
diff --git a/lib/IDE/REPLCodeCompletion.cpp b/lib/IDE/REPLCodeCompletion.cpp
index 2b809974ee0c3..d8243b3ba72b0 100644
--- a/lib/IDE/REPLCodeCompletion.cpp
+++ b/lib/IDE/REPLCodeCompletion.cpp
@@ -256,7 +256,6 @@ doCodeCompletion(SourceFile &SF, StringRef EnteredCode, unsigned *BufferID,
 
   auto &newSF = newModule->getMainSourceFile();
   performImportResolution(newSF);
-  bindExtensions(*newModule);
 
   performIDEInspectionSecondPass(newSF, *CompletionCallbacksFactory);
 
diff --git a/lib/IDE/ReadyForTypeCheckingCallback.h b/lib/IDE/ReadyForTypeCheckingCallback.h
new file mode 100644
index 0000000000000..9237884b322db
--- /dev/null
+++ b/lib/IDE/ReadyForTypeCheckingCallback.h
@@ -0,0 +1,37 @@
+//===--- ReadyForTypeCheckingCallback.h -----------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_IDE_READYFORTYPECHECKINGCALLBACK_H
+#define SWIFT_IDE_READYFORTYPECHECKINGCALLBACK_H
+
+#include "swift/Parse/IDEInspectionCallbacks.h"
+
+namespace swift {
+namespace ide {
+
+/// IDE inspection callback that is invoked once the resulting AST is ready
+/// for type-checking work.
+class ReadyForTypeCheckingCallback : public DoneParsingCallback {
+public:
+  virtual ~ReadyForTypeCheckingCallback() {}
+
+  virtual void doneParsing(SourceFile *SrcFile) override;
+
+  /// Called when the AST has been parsed and had its imports resolved and
+  /// extensions bound.
+  virtual void readyForTypeChecking(SourceFile *SrcFile) = 0;
+};
+
+} // namespace ide
+} // namespace swift
+
+#endif // SWIFT_IDE_READYFORTYPECHECKINGCALLBACK_H
diff --git a/lib/IDE/SelectedOverloadInfo.cpp b/lib/IDE/SelectedOverloadInfo.cpp
index d9a339116fb6c..a1f65adca0ae5 100644
--- a/lib/IDE/SelectedOverloadInfo.cpp
+++ b/lib/IDE/SelectedOverloadInfo.cpp
@@ -56,7 +56,7 @@ swift::ide::getSelectedOverloadInfo(const Solution &S,
         OverloadChoiceKind::KeyPathApplication) {
       auto Params = Result.ValueTy->getAs<AnyFunctionType>()->getParams();
       if (Params.size() == 1 &&
-          Params[0].getPlainType()->is<UnresolvedType>()) {
+          Params[0].getPlainType()->is<ErrorType>()) {
         auto *KPDecl = CS.getASTContext().getKeyPathDecl();
         Type KPTy =
             KPDecl->mapTypeIntoContext(KPDecl->getDeclaredInterfaceType());
@@ -79,7 +79,7 @@ swift::ide::getSelectedOverloadInfo(const Solution &S,
         fnType->getParams()[0].getPlainType()->castTo<BoundGenericType>();
 
     auto *keyPathDecl = keyPathTy->getAnyNominal();
-    assert(isKnownKeyPathType(keyPathTy) &&
+    assert(keyPathTy->isKnownKeyPathType() &&
            "parameter is supposed to be a keypath");
 
     auto KeyPathDynamicLocator = CS.getConstraintLocator(
diff --git a/lib/IDE/SignatureHelp.cpp b/lib/IDE/SignatureHelp.cpp
new file mode 100644
index 0000000000000..2f5b16bc05c5f
--- /dev/null
+++ b/lib/IDE/SignatureHelp.cpp
@@ -0,0 +1,88 @@
+//===--- SignatureHelp.cpp ------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/IDE/SignatureHelp.h"
+#include "ReadyForTypeCheckingCallback.h"
+#include "swift/IDE/ArgumentCompletion.h"
+#include "swift/Sema/IDETypeChecking.h"
+
+using namespace swift;
+using namespace swift::ide;
+using namespace swift::constraints;
+
+namespace {
+class SignatureHelpCallbacks : public CodeCompletionCallbacks,
+                               public ReadyForTypeCheckingCallback {
+  SignatureHelpConsumer &Consumer;
+  SourceLoc Loc;
+  CodeCompletionExpr *CCExpr = nullptr;
+  DeclContext *CurDeclContext = nullptr;
+
+public:
+  SignatureHelpCallbacks(Parser &P, SignatureHelpConsumer &Consumer)
+      : CodeCompletionCallbacks(P), Consumer(Consumer) {}
+
+  // Only handle callbacks for argument completions.
+  // {
+  void completeCallArg(CodeCompletionExpr *E) override;
+  // }
+
+  void readyForTypeChecking(SourceFile *SrcFile) override;
+};
+
+void SignatureHelpCallbacks::completeCallArg(CodeCompletionExpr *E) {
+  CurDeclContext = P.CurDeclContext;
+  CCExpr = E;
+}
+
+void SignatureHelpCallbacks::readyForTypeChecking(SourceFile *SrcFile) {
+  if (!CCExpr)
+    return;
+
+  ArgumentTypeCheckCompletionCallback Lookup(CCExpr, CurDeclContext);
+  {
+    llvm::SaveAndRestore<TypeCheckCompletionCallback *> CompletionCollector(
+        Context.CompletionCallback, &Lookup);
+    swift::typeCheckASTNodeAtLoc(
+        TypeCheckASTNodeAtLocContext::declContext(CurDeclContext),
+        CCExpr->getLoc());
+  }
+
+  SignatureHelpResult Result(CurDeclContext);
+
+  Lookup.getSignatures(CCExpr->getLoc(), CurDeclContext, Result.Signatures);
+
+  Consumer.handleResult(Result);
+}
+
+} // anonymous namespace.
+
+IDEInspectionCallbacksFactory *
+swift::ide::makeSignatureHelpCallbacksFactory(SignatureHelpConsumer &Consumer) {
+
+  // CC callback factory which produces 'SignatureCallbacks'.
+  class SignatureHelpCallbacksFactoryImpl
+      : public IDEInspectionCallbacksFactory {
+    SignatureHelpConsumer &Consumer;
+
+  public:
+    SignatureHelpCallbacksFactoryImpl(SignatureHelpConsumer &Consumer)
+        : Consumer(Consumer) {}
+
+    Callbacks createCallbacks(Parser &P) override {
+      auto Callback = std::make_shared<SignatureHelpCallbacks>(P, Consumer);
+      return {Callback, Callback};
+    }
+  };
+
+  return new SignatureHelpCallbacksFactoryImpl(Consumer);
+}
diff --git a/lib/IDE/SignatureHelpFormatter.cpp b/lib/IDE/SignatureHelpFormatter.cpp
new file mode 100644
index 0000000000000..528a7c668ddbd
--- /dev/null
+++ b/lib/IDE/SignatureHelpFormatter.cpp
@@ -0,0 +1,204 @@
+//===--- SignatureHelpFormatter.cpp --- -------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/IDE/SignatureHelpFormatter.h"
+#include "CodeCompletionStringBuilder.h"
+#include "swift/AST/ParameterList.h"
+#include "swift/IDE/CommentConversion.h"
+
+using namespace swift;
+using namespace swift::ide;
+
+using ChunkKind = CodeCompletionString::Chunk::ChunkKind;
+
+/// \returns Array of parameters of \p VD accounting for implicitly curried
+/// instance methods.
+static ArrayRef<const ParamDecl *>
+getParameterArray(const ValueDecl *VD, bool IsImplicitlyCurried,
+                  const ParamDecl *&Scratch) {
+  if (!VD)
+    return {};
+
+  if (IsImplicitlyCurried) {
+    auto *FD = dyn_cast<AbstractFunctionDecl>(VD);
+    assert(FD && FD->hasImplicitSelfDecl());
+
+    Scratch = FD->getImplicitSelfDecl();
+    return ArrayRef(&Scratch, 1);
+  }
+
+  if (auto *ParamList = VD->getParameterList())
+    return ParamList->getArray();
+
+  return {};
+}
+
+static StringRef copyAndClearString(llvm::BumpPtrAllocator &Allocator,
+                                    SmallVectorImpl<char> &Str) {
+  auto Ref = StringRef(Str.data(), Str.size()).copy(Allocator);
+  Str.clear();
+  return Ref;
+}
+
+CodeCompletionString *
+SignatureHelpFormatter::createSignatureString(const ide::Signature &Signature,
+                                              const DeclContext *DC) {
+  ValueDecl *FD = Signature.FuncD;
+  AnyFunctionType *AFT = Signature.FuncTy;
+
+  GenericSignature GenericSig;
+  if (FD) {
+    if (auto *GC = FD->getAsGenericContext())
+      GenericSig = GC->getGenericSignature();
+  }
+
+  CodeCompletionStringBuilder StringBuilder(
+      Allocator, /*AnnotateResults=*/false,
+      /*UnderscoreEmptyArgumentLabel=*/!Signature.IsSubscript,
+      /*FullParameterFlags=*/true);
+
+  DeclBaseName BaseName;
+
+  if (!Signature.IsSecondApply && FD) {
+    BaseName = FD->getBaseName();
+  } else if (Signature.IsSubscript) {
+    BaseName = DeclBaseName::createSubscript();
+  }
+
+  if (!BaseName.empty())
+    StringBuilder.addValueBaseName(BaseName,
+                                   /*IsMember=*/bool(Signature.BaseType));
+
+  StringBuilder.addLeftParen();
+
+  const ParamDecl *ParamScratch;
+  StringBuilder.addCallArgumentPatterns(
+      AFT->getParams(),
+      getParameterArray(FD, Signature.IsImplicitlyCurried, ParamScratch), DC,
+      GenericSig, DefaultArgumentOutputMode::All,
+      /*includeDefaultValues=*/true);
+
+  StringBuilder.addRightParen();
+
+  if (!Signature.IsImplicitlyCurried) {
+    if (Signature.IsSecondApply) {
+      // For a second apply, we don't pass the declaration to avoid adding
+      // incorrect rethrows and reasync which are only usable in a single apply.
+      StringBuilder.addEffectsSpecifiers(AFT, /*AFD=*/nullptr);
+    } else {
+      StringBuilder.addEffectsSpecifiers(
+          AFT, dyn_cast_or_null<AbstractFunctionDecl>(FD));
+    }
+  }
+
+  if (FD && FD->isImplicitlyUnwrappedOptional()) {
+    StringBuilder.addTypeAnnotationForImplicitlyUnwrappedOptional(
+        AFT->getResult(), DC, GenericSig);
+  } else {
+    StringBuilder.addTypeAnnotation(AFT->getResult(), DC, GenericSig);
+  }
+
+  return StringBuilder.createCompletionString();
+}
+
+FormattedSignatureHelp::Signature
+SignatureHelpFormatter::formatSignature(const DeclContext *DC,
+                                        const ide::Signature &Signature) {
+  auto *FD = Signature.FuncD;
+  auto *AFT = Signature.FuncTy;
+
+  bool IsConstructor = isa_and_nonnull<ConstructorDecl>(FD);
+
+  auto *SignatureString = createSignatureString(Signature, DC);
+
+  llvm::SmallString<512> SS;
+  llvm::raw_svector_ostream OS(SS);
+
+  bool SkipResult = AFT->getResult()->isVoid() || IsConstructor;
+
+  SmallVector<FormattedSignatureHelp::Parameter, 8> FormattedParams;
+
+  auto Chunks = SignatureString->getChunks();
+  auto C = Chunks.begin();
+  while (C != Chunks.end()) {
+    if (C->is(ChunkKind::TypeAnnotation) && SkipResult) {
+      ++C;
+      continue;
+    }
+
+    if (C->is(ChunkKind::TypeAnnotation))
+      OS << " -> ";
+
+    if (C->is(ChunkKind::CallArgumentBegin)) {
+      unsigned NestingLevel = C->getNestingLevel();
+      ++C;
+
+      auto &P = FormattedParams.emplace_back();
+      P.Offset = SS.size();
+
+      do {
+        if (!C->is(ChunkKind::CallArgumentClosureType) && C->hasText())
+          OS << C->getText();
+
+        ++C;
+      } while (C != Chunks.end() && !C->endsPreviousNestedGroup(NestingLevel));
+
+      P.Length = SS.size() - P.Offset;
+      continue;
+    }
+
+    if (C->hasText())
+      OS << C->getText();
+
+    ++C;
+  }
+
+  StringRef SignatureText = copyAndClearString(Allocator, SS);
+
+  // Parameter names.
+  const ParamDecl *ParamScratch;
+  auto ParamDecls =
+      getParameterArray(FD, Signature.IsImplicitlyCurried, ParamScratch);
+
+  if (!ParamDecls.empty()) {
+    for (unsigned i = 0; i < FormattedParams.size(); ++i) {
+      FormattedParams[i].Name = ParamDecls[i]->getParameterName().str();
+    }
+  }
+
+  // Documentation.
+  StringRef DocComment;
+  if (FD) {
+    ide::getRawDocumentationComment(FD, OS);
+    DocComment = copyAndClearString(Allocator, SS);
+  }
+
+  return FormattedSignatureHelp::Signature(
+      SignatureText, DocComment, Signature.ParamIdx,
+      ArrayRef(FormattedParams).copy(Allocator));
+}
+
+FormattedSignatureHelp
+SignatureHelpFormatter::format(SignatureHelpResult Result) {
+  SmallVector<FormattedSignatureHelp::Signature, 8> FormattedSignatures;
+  FormattedSignatures.reserve(Result.Signatures.size());
+
+  for (auto &Signature : Result.Signatures) {
+    FormattedSignatures.push_back(formatSignature(Result.DC, Signature));
+  }
+
+  // FIXME: Ideally we should select an active signature based on the context.
+  unsigned ActiveSignature = 0;
+
+  return FormattedSignatureHelp(ArrayRef(FormattedSignatures).copy(Allocator),
+                                ActiveSignature);
+}
diff --git a/lib/IDE/SourceEntityWalker.cpp b/lib/IDE/SourceEntityWalker.cpp
index 5fabc325f13ad..f11281be71863 100644
--- a/lib/IDE/SourceEntityWalker.cpp
+++ b/lib/IDE/SourceEntityWalker.cpp
@@ -728,7 +728,7 @@ bool SemaAnnotator::handleCustomAttributes(Decl *D) {
 
   ModuleDecl *MD = D->getModuleContext();
   for (auto *customAttr :
-       D->getSemanticAttrs().getAttributes<CustomAttr, true>()) {
+       D->getExpandedAttrs().getAttributes<CustomAttr, true>()) {
     SourceFile *SF =
         MD->getSourceFileContainingLocation(customAttr->getLocation());
     ASTNode expansion = SF ? SF->getMacroExpansion() : nullptr;
@@ -743,7 +743,7 @@ bool SemaAnnotator::handleCustomAttributes(Decl *D) {
       if (auto macroDecl = D->getResolvedMacro(mutableAttr)) {
         Type macroRefType = macroDecl->getDeclaredInterfaceType();
         auto customAttrRef =
-            std::make_pair(customAttr, expansion ? expansion.get<Decl *>() : D);
+            std::make_pair(customAttr, expansion ? cast<Decl *>(expansion) : D);
         auto refMetadata =
             ReferenceMetaData(SemaReferenceKind::DeclRef, std::nullopt,
                               /*isImplicit=*/false, customAttrRef);
@@ -796,10 +796,10 @@ bool SemaAnnotator::handleClosureAttributes(ClosureExpr *E) {
 
 bool SemaAnnotator::handleTypeAttributes(AttributedTypeRepr *T) {
   for (auto attr : T->getAttrs()) {
-    if (!attr.is<CustomAttr *>())
+    if (!isa<CustomAttr *>(attr))
       continue;
 
-    CustomAttr *customAttr = attr.get<CustomAttr *>();
+    CustomAttr *customAttr = cast<CustomAttr *>(attr);
     if (!handleCustomTypeAttribute(customAttr))
       return false;
   }
@@ -851,28 +851,17 @@ bool SemaAnnotator::passModulePathElements(
 bool SemaAnnotator::passSubscriptReference(ValueDecl *D, SourceLoc Loc,
                                            ReferenceMetaData Data,
                                            bool IsOpenBracket) {
-  CharSourceRange Range = Loc.isValid()
-                        ? CharSourceRange(Loc, 1)
-                        : CharSourceRange();
-
-  return SEWalker.visitSubscriptReference(D, Range, Data, IsOpenBracket);
+  return SEWalker.visitSubscriptReference(D, Loc, Data, IsOpenBracket);
 }
 
 bool SemaAnnotator::passCallAsFunctionReference(ValueDecl *D, SourceLoc Loc,
                                                 ReferenceMetaData Data) {
-  CharSourceRange Range =
-      Loc.isValid() ? CharSourceRange(Loc, 1) : CharSourceRange();
-
-  return SEWalker.visitCallAsFunctionReference(D, Range, Data);
+  return SEWalker.visitCallAsFunctionReference(D, Loc, Data);
 }
 
 bool SemaAnnotator::
 passReference(ValueDecl *D, Type Ty, DeclNameLoc Loc, ReferenceMetaData Data) {
-  SourceManager &SM = D->getASTContext().SourceMgr;
-  SourceLoc BaseStart = Loc.getBaseNameLoc(), BaseEnd = BaseStart;
-  if (BaseStart.isValid() && SM.extractText({BaseStart, 1}) == "`")
-    BaseEnd = Lexer::getLocForEndOfToken(SM, BaseStart.getAdvancedLoc(1));
-  return passReference(D, Ty, BaseStart, {BaseStart, BaseEnd}, Data);
+  return passReference(D, Ty, Loc.getBaseNameLoc(), Loc.getSourceRange(), Data);
 }
 
 bool SemaAnnotator::
@@ -917,12 +906,7 @@ passReference(ValueDecl *D, Type Ty, SourceLoc BaseNameLoc, SourceRange Range,
     }
   }
 
-  CharSourceRange CharRange =
-    Lexer::getCharSourceRangeFromSourceRange(D->getASTContext().SourceMgr,
-                                             Range);
-
-  return SEWalker.visitDeclReference(D, CharRange, CtorTyRef, ExtDecl, Ty,
-                                     Data);
+  return SEWalker.visitDeclReference(D, Range, CtorTyRef, ExtDecl, Ty, Data);
 }
 
 bool SemaAnnotator::passReference(ModuleEntity Mod,
@@ -1023,7 +1007,7 @@ bool SourceEntityWalker::walk(ASTNode N) {
   llvm_unreachable("unsupported AST node");
 }
 
-bool SourceEntityWalker::visitDeclReference(ValueDecl *D, CharSourceRange Range,
+bool SourceEntityWalker::visitDeclReference(ValueDecl *D, SourceRange Range,
                                             TypeDecl *CtorTyRef,
                                             ExtensionDecl *ExtTyRef, Type T,
                                             ReferenceMetaData Data) {
@@ -1031,7 +1015,7 @@ bool SourceEntityWalker::visitDeclReference(ValueDecl *D, CharSourceRange Range,
 }
 
 bool SourceEntityWalker::visitSubscriptReference(ValueDecl *D,
-                                                 CharSourceRange Range,
+                                                 SourceRange Range,
                                                  ReferenceMetaData Data,
                                                  bool IsOpenBracket) {
   // Most of the clients treat subscript reference the same way as a
@@ -1043,7 +1027,7 @@ bool SourceEntityWalker::visitSubscriptReference(ValueDecl *D,
 }
 
 bool SourceEntityWalker::visitCallAsFunctionReference(ValueDecl *D,
-                                                      CharSourceRange Range,
+                                                      SourceRange Range,
                                                       ReferenceMetaData Data) {
   return true;
 }
diff --git a/lib/IDE/SwiftSourceDocInfo.cpp b/lib/IDE/SwiftSourceDocInfo.cpp
index 0befbf75b9a19..1d8660bd36ef3 100644
--- a/lib/IDE/SwiftSourceDocInfo.cpp
+++ b/lib/IDE/SwiftSourceDocInfo.cpp
@@ -70,7 +70,8 @@ void XMLEscapingPrinter::printXML(StringRef Text) {
   OS << Text;
 }
 
-void ResolvedRangeInfo::print(llvm::raw_ostream &OS) const {
+void ResolvedRangeInfo::print(llvm::raw_ostream &OS,
+                              const PrintOptions &PO) const {
   OS << "<Kind>";
   switch (Kind) {
   case RangeKind::SingleExpression: OS << "SingleExpression"; break;
@@ -87,7 +88,7 @@ void ResolvedRangeInfo::print(llvm::raw_ostream &OS) const {
 
   if (auto Ty = getType()) {
     OS << "<Type>";
-    Ty->print(OS);
+    Ty->print(OS, PO);
     OS << "</Type>";
     switch(exit()) {
     case ExitState::Positive: OS << "<Exit>true</Exit>"; break;
@@ -147,7 +148,7 @@ void ResolvedRangeInfo::print(llvm::raw_ostream &OS) const {
   for (auto &RD : ReferencedDecls) {
     OS << "<Referenced>" << RD.VD->getBaseName() << "</Referenced>";
     OS << "<Type>";
-    RD.Ty->print(OS);
+    RD.Ty->print(OS, PO);
     OS << "</Type>\n";
   }
 
diff --git a/lib/IDE/SyntaxModel.cpp b/lib/IDE/SyntaxModel.cpp
index 18ce9b7a8f24e..8fbdddc7d45b0 100644
--- a/lib/IDE/SyntaxModel.cpp
+++ b/lib/IDE/SyntaxModel.cpp
@@ -1196,7 +1196,7 @@ bool ModelASTWalker::handleAttrs(ArrayRef<TypeOrCustomAttr> Attrs) {
     if (auto CA = Attr.dyn_cast<CustomAttr*>()) {
       DeclRanges.push_back(std::make_pair(CA, CA->getRangeWithAt()));
     } else {
-      auto TA = Attr.get<TypeAttribute*>();
+      auto TA = cast<TypeAttribute *>(Attr);
       // TODO: Use the structure in the TypeAttribute
       DeclRanges.push_back(std::make_pair(nullptr, SourceRange(TA->getStartLoc())));
     }
diff --git a/lib/IDE/TypeCheckCompletionCallback.cpp b/lib/IDE/TypeCheckCompletionCallback.cpp
index e068312deee23..cfb6ebedd9239 100644
--- a/lib/IDE/TypeCheckCompletionCallback.cpp
+++ b/lib/IDE/TypeCheckCompletionCallback.cpp
@@ -10,10 +10,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "swift/Basic/Assertions.h"
 #include "swift/IDE/TypeCheckCompletionCallback.h"
+#include "swift/Basic/Assertions.h"
 #include "swift/IDE/CompletionLookup.h"
-#include "swift/Sema/CompletionContextFinder.h"
 #include "swift/Sema/ConstraintSystem.h"
 #include "swift/Sema/IDETypeChecking.h"
 
@@ -21,29 +20,6 @@ using namespace swift;
 using namespace swift::ide;
 using namespace swift::constraints;
 
-void TypeCheckCompletionCallback::fallbackTypeCheck(DeclContext *DC) {
-  assert(!GotCallback);
-
-  auto finder = CompletionContextFinder::forFallback(DC);
-  if (!finder.hasCompletionExpr())
-    return;
-
-  auto fallback = finder.getFallbackCompletionExpr();
-  if (!fallback || isa<AbstractClosureExpr>(fallback->DC)) {
-    // If the expression is embedded in a closure, the constraint system tries
-    // to retrieve that closure's type, which will fail since we won't have
-    // generated any type variables for it. Thus, fallback type checking isn't
-    // available in this case.
-    return;
-  }
-
-  SyntacticElementTarget completionTarget(fallback->E, fallback->DC, CTP_Unused,
-                                          Type(),
-                                          /*isDiscared=*/true);
-  typeCheckForCodeCompletion(completionTarget, /*needsPrecheck=*/true,
-                             [&](const Solution &S) { sawSolution(S); });
-}
-
 // MARK: - Utility functions for subclasses of TypeCheckCompletionCallback
 
 Type swift::ide::getTypeForCompletion(const constraints::Solution &S,
@@ -51,14 +27,14 @@ Type swift::ide::getTypeForCompletion(const constraints::Solution &S,
   // Use the contextual type, unless it is still unresolved, in which case fall
   // back to getting the type from the expression.
   if (auto ContextualType = S.getContextualType(Node)) {
-    if (!ContextualType->hasUnresolvedType() &&
+    if (!ContextualType->hasError() &&
         !ContextualType->hasUnboundGenericType()) {
       return ContextualType;
     }
   }
 
   if (!S.hasType(Node)) {
-    assert(false && "Expression wasn't type checked?");
+    CONDITIONAL_ASSERT(false && "Expression wasn't type checked?");
     return nullptr;
   }
 
@@ -70,7 +46,7 @@ Type swift::ide::getTypeForCompletion(const constraints::Solution &S,
     Result = S.getResolvedType(Node);
   }
 
-  if (Result && Result->is<UnresolvedType>()) {
+  if (Result && Result->is<ErrorType>()) {
     Result = Type();
   }
   return Result;
diff --git a/lib/IDE/TypeContextInfo.cpp b/lib/IDE/TypeContextInfo.cpp
index bd587f2005c20..4dad77c2a683a 100644
--- a/lib/IDE/TypeContextInfo.cpp
+++ b/lib/IDE/TypeContextInfo.cpp
@@ -12,6 +12,7 @@
 
 #include "swift/IDE/TypeContextInfo.h"
 #include "ExprContextAnalysis.h"
+#include "ReadyForTypeCheckingCallback.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/USRGeneration.h"
@@ -27,7 +28,7 @@ using namespace swift;
 using namespace ide;
 
 class ContextInfoCallbacks : public CodeCompletionCallbacks,
-                             public DoneParsingCallback {
+                             public ReadyForTypeCheckingCallback {
   TypeContextInfoConsumer &Consumer;
   SourceLoc Loc;
   Expr *ParsedExpr = nullptr;
@@ -37,7 +38,7 @@ class ContextInfoCallbacks : public CodeCompletionCallbacks,
 
 public:
   ContextInfoCallbacks(Parser &P, TypeContextInfoConsumer &Consumer)
-      : CodeCompletionCallbacks(P), DoneParsingCallback(), Consumer(Consumer) {}
+      : CodeCompletionCallbacks(P), Consumer(Consumer) {}
 
   void completePostfixExprBeginning(CodeCompletionExpr *E) override;
   void completeForEachSequenceBeginning(CodeCompletionExpr *E) override;
@@ -52,7 +53,7 @@ class ContextInfoCallbacks : public CodeCompletionCallbacks,
   void completeUnresolvedMember(CodeCompletionExpr *E,
                                 SourceLoc DotLoc) override;
 
-  void doneParsing(SourceFile *SrcFile) override;
+  void readyForTypeChecking(SourceFile *SrcFile) override;
 };
 
 void ContextInfoCallbacks::completePostfixExprBeginning(CodeCompletionExpr *E) {
@@ -111,7 +112,7 @@ class TypeContextInfoCallback : public TypeCheckCompletionCallback {
   ArrayRef<Type> getTypes() const { return Types; }
 };
 
-void ContextInfoCallbacks::doneParsing(SourceFile *SrcFile) {
+void ContextInfoCallbacks::readyForTypeChecking(SourceFile *SrcFile) {
   if (!ParsedExpr)
     return;
 
@@ -119,7 +120,7 @@ void ContextInfoCallbacks::doneParsing(SourceFile *SrcFile) {
   {
     llvm::SaveAndRestore<TypeCheckCompletionCallback *> CompletionCollector(
         Context.CompletionCallback, &TypeCheckCallback);
-    typeCheckContextAt(
+    swift::typeCheckASTNodeAtLoc(
         TypeCheckASTNodeAtLocContext::declContext(CurDeclContext),
         ParsedExpr->getLoc());
   }
@@ -128,7 +129,7 @@ void ContextInfoCallbacks::doneParsing(SourceFile *SrcFile) {
   SmallVector<TypeContextInfoItem, 2> results;
 
   for (auto T : TypeCheckCallback.getTypes()) {
-    if (T->is<ErrorType>() || T->is<UnresolvedType>())
+    if (T->is<ErrorType>())
       continue;
 
     T = T->getRValueType();
diff --git a/lib/IDE/UnresolvedMemberCompletion.cpp b/lib/IDE/UnresolvedMemberCompletion.cpp
index 978a3ca5c03c0..f92ae492f8237 100644
--- a/lib/IDE/UnresolvedMemberCompletion.cpp
+++ b/lib/IDE/UnresolvedMemberCompletion.cpp
@@ -10,11 +10,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "swift/Basic/Assertions.h"
 #include "swift/IDE/UnresolvedMemberCompletion.h"
+#include "swift/Basic/Assertions.h"
 #include "swift/IDE/CodeCompletion.h"
 #include "swift/IDE/CompletionLookup.h"
-#include "swift/Sema/CompletionContextFinder.h"
 #include "swift/Sema/ConstraintSystem.h"
 #include "swift/Sema/IDETypeChecking.h"
 
diff --git a/lib/IDE/Utils.cpp b/lib/IDE/Utils.cpp
index 6dbb2fb7aa320..9e6721b5f9c5d 100644
--- a/lib/IDE/Utils.cpp
+++ b/lib/IDE/Utils.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -20,7 +20,7 @@
 #include "swift/Parse/Parser.h"
 #include "swift/Subsystems.h"
 #include "clang/AST/ASTContext.h"
-#include "clang/Rewrite/Core/RewriteBuffer.h"
+#include "llvm/ADT/RewriteBuffer.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -782,11 +782,11 @@ accept(SourceManager &SM, RegionType Type, ArrayRef<Replacement> Replacements) {
 namespace {
 class ClangFileRewriterHelper {
   unsigned InterestedId;
-  clang::RewriteBuffer RewriteBuf;
+  llvm::RewriteBuffer RewriteBuf;
   bool HasChange;
   llvm::raw_ostream &OS;
 
-  void removeCommentLines(clang::RewriteBuffer &Buffer, StringRef Input,
+  void removeCommentLines(llvm::RewriteBuffer &Buffer, StringRef Input,
                           StringRef LineHeader) {
     size_t Pos = 0;
     while (true) {
@@ -1105,28 +1105,22 @@ extern "C" {
 /// - Parameters:
 ///   - sourceFilePtr: A pointer to an `ExportedSourceFile`, used to access the
 ///     syntax tree
-///   - locations: Pointer to a buffer of `BridgedSourceLoc` that should be
+///   - locations: Pointer to a buffer of `SourceLoc` that should be
 ///     resolved by the name matcher.
 ///   - locationsCount: Number of elements in `locations`.
 /// - Returns: The opaque value of a `BridgedResolvedLocVector`.
 void *swift_SwiftIDEUtilsBridging_runNameMatcher(const void *sourceFilePtr,
-                                                 BridgedSourceLoc *locations,
+                                                 const SourceLoc *locations,
                                                  size_t locationsCount);
 }
 
 std::vector<ResolvedLoc>
 swift::ide::runNameMatcher(const SourceFile &sourceFile,
                            ArrayRef<SourceLoc> locations) {
-  std::vector<BridgedSourceLoc> bridgedUnresolvedLocs;
-  bridgedUnresolvedLocs.reserve(locations.size());
-  for (SourceLoc loc : locations) {
-    bridgedUnresolvedLocs.push_back(BridgedSourceLoc(loc));
-  }
-
   BridgedResolvedLocVector bridgedResolvedLocs =
       swift_SwiftIDEUtilsBridging_runNameMatcher(
-          sourceFile.getExportedSourceFile(), bridgedUnresolvedLocs.data(),
-          bridgedUnresolvedLocs.size());
+          sourceFile.getExportedSourceFile(), locations.data(),
+          locations.size());
   return bridgedResolvedLocs.takeUnbridged();
 }
 #endif // SWIFT_BUILD_SWIFT_SYNTAX
diff --git a/lib/IDETool/CompileInstance.cpp b/lib/IDETool/CompileInstance.cpp
index 84a6ef1ae198d..8392591793243 100644
--- a/lib/IDETool/CompileInstance.cpp
+++ b/lib/IDETool/CompileInstance.cpp
@@ -258,11 +258,9 @@ bool CompileInstance::setupCI(
   auto &Diags = CI->getDiags();
 
   SmallVector<const char *, 16> args;
-  // Put '-resource-dir' and '-diagnostic-documentation-path' at the top to
-  // allow overriding them with the passed in arguments.
+  // Put '-resource-dir' at the top to allow overriding them with the passed in
+  // arguments.
   args.append({"-resource-dir", RuntimeResourcePath.c_str()});
-  args.append({"-Xfrontend", "-diagnostic-documentation-path", "-Xfrontend",
-               DiagnosticDocumentationPath.c_str()});
   args.append(origArgs.begin(), origArgs.end());
 
   SmallString<256> driverPath(SwiftExecutablePath);
diff --git a/lib/IDETool/CompilerInvocation.cpp b/lib/IDETool/CompilerInvocation.cpp
index da49990804c78..1e1dfa05ace27 100644
--- a/lib/IDETool/CompilerInvocation.cpp
+++ b/lib/IDETool/CompilerInvocation.cpp
@@ -157,18 +157,13 @@ bool ide::initCompilerInvocation(
     StringRef UnresolvedPrimaryFile,
     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
     const std::string &swiftExecutablePath,
-    const std::string &runtimeResourcePath,
-    const std::string &diagnosticDocumentationPath, time_t sessionTimestamp,
+    const std::string &runtimeResourcePath, time_t sessionTimestamp,
     std::string &Error) {
   SmallVector<const char *, 16> Args;
-  // Make sure to put '-resource-dir' and '-diagnostic-documentation-path' at
-  // the top to allow overriding them with the passed in arguments.
+  // Make sure to put '-resource-dir' at the top to allow overriding them with
+  // the passed in arguments.
   Args.push_back("-resource-dir");
   Args.push_back(runtimeResourcePath.c_str());
-  Args.push_back("-Xfrontend");
-  Args.push_back("-diagnostic-documentation-path");
-  Args.push_back("-Xfrontend");
-  Args.push_back(diagnosticDocumentationPath.c_str());
   Args.append(OrigArgs.begin(), OrigArgs.end());
 
   SmallString<32> ErrStr;
@@ -272,13 +267,12 @@ bool ide::initCompilerInvocation(
 bool ide::initInvocationByClangArguments(ArrayRef<const char *> ArgList,
                                          CompilerInvocation &Invok,
                                          std::string &Error) {
-  llvm::IntrusiveRefCntPtr<clang::DiagnosticOptions> DiagOpts{
-    new clang::DiagnosticOptions()
-  };
+  const auto VFS = llvm::vfs::getRealFileSystem();
 
   clang::TextDiagnosticBuffer DiagBuf;
+  clang::DiagnosticOptions DiagOpts;
   llvm::IntrusiveRefCntPtr<clang::DiagnosticsEngine> ClangDiags =
-      clang::CompilerInstance::createDiagnostics(DiagOpts.get(), &DiagBuf,
+      clang::CompilerInstance::createDiagnostics(*VFS, DiagOpts, &DiagBuf,
                                                  /*ShouldOwnClient=*/false);
 
   // Clang expects this to be like an actual command line. So we need to pass in
@@ -356,7 +350,7 @@ bool ide::initInvocationByClangArguments(ArrayRef<const char *> ArgList,
 
   if (!PPOpts.ImplicitPCHInclude.empty()) {
     clang::FileSystemOptions FileSysOpts;
-    clang::FileManager FileMgr(FileSysOpts);
+    clang::FileManager FileMgr(FileSysOpts, VFS);
     auto PCHContainerOperations =
         std::make_shared<clang::PCHContainerOperations>();
     std::string HeaderFile = clang::ASTReader::getOriginalSourceFile(
diff --git a/lib/IDETool/IDEInspectionInstance.cpp b/lib/IDETool/IDEInspectionInstance.cpp
index ebb0e086983f1..d54070998be36 100644
--- a/lib/IDETool/IDEInspectionInstance.cpp
+++ b/lib/IDETool/IDEInspectionInstance.cpp
@@ -63,9 +63,10 @@ swift::ide::makeCodeCompletionMemoryBuffer(const llvm::MemoryBuffer *origBuf,
 }
 
 namespace {
-/// Returns index number of \p D in \p Decls . If it's not found, returns ~0.
+/// Returns index number of \p D in \p Decls . If it's not found, returns
+/// \c nullopt.
 template <typename Range>
-unsigned findIndexInRange(Decl *D, const Range &Decls) {
+std::optional<unsigned> findIndexInRange(Decl *D, const Range &Decls) {
   unsigned N = 0;
   for (auto I = Decls.begin(), E = Decls.end(); I != E; ++I) {
     if ((*I)->isImplicit())
@@ -74,7 +75,7 @@ unsigned findIndexInRange(Decl *D, const Range &Decls) {
       return N;
     ++N;
   }
-  return ~0U;
+  return std::nullopt;
 }
 
 /// Return the element at \p N in \p Decls .
@@ -89,6 +90,23 @@ template <typename Range> Decl *getElementAt(const Range &Decls, unsigned N) {
   return nullptr;
 }
 
+static ArrayRef<AccessorDecl *>
+getParsedAccessors(AbstractStorageDecl *ASD,
+                   SmallVectorImpl<AccessorDecl *> &scratch) {
+  ASSERT(scratch.empty());
+  ASD->visitParsedAccessors([&](auto *AD) {
+    // Ignore accessors added by macro expansions.
+    // TODO: This ought to be the default behavior of `visitParsedAccessors`,
+    // we ought to have a different entrypoint for clients that care about
+    // the semantic set of "explicit" accessors.
+    if (AD->isInMacroExpansionInContext())
+      return;
+
+    scratch.push_back(AD);
+  });
+  return scratch;
+}
+
 /// Find the equivalent \c DeclContext with \p DC from \p SF AST.
 /// This assumes the AST which contains \p DC has exact the same structure with
 /// \p SF.
@@ -106,7 +124,7 @@ static DeclContext *getEquivalentDeclContextFromSourceFile(DeclContext *DC,
     if (!D)
       return nullptr;
     auto *parentDC = newDC->getParent();
-    unsigned N = ~0U;
+    std::optional<unsigned> N;
 
     if (auto accessor = dyn_cast<AccessorDecl>(D)) {
       // The AST for accessors is like:
@@ -116,8 +134,13 @@ static DeclContext *getEquivalentDeclContextFromSourceFile(DeclContext *DC,
       auto *storage = accessor->getStorage();
       if (!storage)
         return nullptr;
-      auto accessorN = findIndexInRange(accessor, storage->getAllAccessors());
-      IndexStack.push_back(accessorN);
+
+      SmallVector<AccessorDecl *, 4> scratch;
+      auto accessorN =
+          findIndexInRange(accessor, getParsedAccessors(storage, scratch));
+      if (!accessorN)
+        return nullptr;
+      IndexStack.push_back(*accessorN);
       D = storage;
     }
 
@@ -125,7 +148,7 @@ static DeclContext *getEquivalentDeclContextFromSourceFile(DeclContext *DC,
       N = findIndexInRange(D, parentSF->getTopLevelDecls());
     } else if (auto parentIDC = dyn_cast_or_null<IterableDeclContext>(
                    parentDC->getAsDecl())) {
-      N = findIndexInRange(D, parentIDC->getMembers());
+      N = findIndexInRange(D, parentIDC->getParsedMembers());
     } else {
 #ifndef NDEBUG
       llvm_unreachable("invalid DC kind for finding equivalent DC (indexpath)");
@@ -134,11 +157,10 @@ static DeclContext *getEquivalentDeclContextFromSourceFile(DeclContext *DC,
     }
 
     // Not found in the decl context tree.
-    if (N == ~0U) {
+    if (!N)
       return nullptr;
-    }
 
-    IndexStack.push_back(N);
+    IndexStack.push_back(*N);
     newDC = parentDC;
   } while (!newDC->isModuleScopeContext());
 
@@ -153,7 +175,7 @@ static DeclContext *getEquivalentDeclContextFromSourceFile(DeclContext *DC,
     if (auto parentSF = dyn_cast<SourceFile>(newDC))
       D = getElementAt(parentSF->getTopLevelDecls(), N);
     else if (auto parentIDC = dyn_cast<IterableDeclContext>(newDC->getAsDecl()))
-      D = getElementAt(parentIDC->getMembers(), N);
+      D = getElementAt(parentIDC->getParsedMembers(), N);
     else
       llvm_unreachable("invalid DC kind for finding equivalent DC (query)");
 
@@ -161,7 +183,8 @@ static DeclContext *getEquivalentDeclContextFromSourceFile(DeclContext *DC,
       if (IndexStack.empty())
         return nullptr;
       auto accessorN = IndexStack.pop_back_val();
-      D = getElementAt(storage->getAllAccessors(), accessorN);
+      SmallVector<AccessorDecl *, 4> scratch;
+      D = getElementAt(getParsedAccessors(storage, scratch), accessorN);
     }
 
     newDC = dyn_cast_or_null<DeclContext>(D);
@@ -190,8 +213,10 @@ bool IDEInspectionInstance::performCachedOperationIfPossible(
 
   // Check the invalidation first. Otherwise, in case no 'CacheCI' exists yet,
   // the flag will remain 'true' even after 'CachedCI' is populated.
-  if (CachedCIShouldBeInvalidated.exchange(false))
+  if (CachedCIShouldBeInvalidated.exchange(false)) {
+    CachedCI = nullptr;
     return false;
+  }
   if (!CachedCI)
     return false;
   if (CachedReuseCount >= Opts.MaxASTReuseCount)
@@ -356,7 +381,7 @@ bool IDEInspectionInstance::performCachedOperationIfPossible(
           nullptr
         }
     );
-    SM.recordSourceFile(newBufferID, AFD->getParentSourceFile());
+    SM.recordSourceFile(newBufferID, oldSF);
 
     AFD->setBodyToBeReparsed(newBodyRange);
     oldSF->clearScope();
@@ -404,7 +429,6 @@ bool IDEInspectionInstance::performCachedOperationIfPossible(
     // re-use imported modules.
     auto *newSF = &newM->getMainSourceFile();
     performImportResolution(*newSF);
-    bindExtensions(*newM);
 
     traceDC = newM;
 #ifndef NDEBUG
@@ -493,7 +517,7 @@ void IDEInspectionInstance::performNewOperation(
     CI->getASTContext().CancellationFlag = CancellationFlag;
     registerIDERequestFunctions(CI->getASTContext().evaluator);
 
-    CI->performParseAndResolveImportsOnly();
+    performImportResolution(CI->getMainModule());
 
     bool DidFindIDEInspectionTarget = CI->getIDEInspectionFile()
                                         ->getDelayedParserState()
@@ -812,6 +836,71 @@ void swift::ide::IDEInspectionInstance::conformingMethodList(
       });
 }
 
+void swift::ide::IDEInspectionInstance::signatureHelp(
+    swift::CompilerInvocation &Invocation, llvm::ArrayRef<const char *> Args,
+    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
+    llvm::MemoryBuffer *ideInspectionTargetBuffer, unsigned int Offset,
+    DiagnosticConsumer *DiagC,
+    std::shared_ptr<std::atomic<bool>> CancellationFlag,
+    llvm::function_ref<void(CancellableResult<SignatureHelpResults>)>
+        Callback) {
+  using ResultType = CancellableResult<SignatureHelpResults>;
+
+  struct ConsumerToCallbackAdapter : public swift::ide::SignatureHelpConsumer {
+    bool ReusingASTContext;
+    std::shared_ptr<std::atomic<bool>> CancellationFlag;
+    llvm::function_ref<void(ResultType)> Callback;
+    bool HandleResultsCalled = false;
+
+    ConsumerToCallbackAdapter(
+        bool ReusingASTContext,
+        std::shared_ptr<std::atomic<bool>> CancellationFlag,
+        llvm::function_ref<void(ResultType)> Callback)
+        : ReusingASTContext(ReusingASTContext),
+          CancellationFlag(CancellationFlag), Callback(Callback) {}
+
+    void handleResult(const SignatureHelpResult &result) override {
+      HandleResultsCalled = true;
+      if (CancellationFlag &&
+          CancellationFlag->load(std::memory_order_relaxed)) {
+        Callback(ResultType::cancelled());
+      } else {
+        Callback(ResultType::success({&result, ReusingASTContext}));
+      }
+    }
+  };
+
+  performOperation(
+      Invocation, Args, FileSystem, ideInspectionTargetBuffer, Offset, DiagC,
+      CancellationFlag,
+      [&](CancellableResult<IDEInspectionInstanceResult> CIResult) {
+        CIResult.mapAsync<SignatureHelpResults>(
+            [&CancellationFlag](auto &Result, auto DeliverTransformed) {
+              ConsumerToCallbackAdapter Consumer(
+                  Result.DidReuseAST, CancellationFlag, DeliverTransformed);
+              std::unique_ptr<IDEInspectionCallbacksFactory> callbacksFactory(
+                  ide::makeSignatureHelpCallbacksFactory(Consumer));
+
+              if (!Result.DidFindIDEInspectionTarget) {
+                DeliverTransformed(
+                    ResultType::success({/*Results=*/{}, Result.DidReuseAST}));
+              }
+
+              performIDEInspectionSecondPass(*Result.CI->getIDEInspectionFile(),
+                                             *callbacksFactory);
+              if (!Consumer.HandleResultsCalled) {
+                // If we didn't receive a handleResult call from the second
+                // pass, we didn't receive any results. To make sure Callback
+                // gets called exactly once, call it manually with no results
+                // here.
+                DeliverTransformed(
+                    ResultType::success({/*Results=*/{}, Result.DidReuseAST}));
+              }
+            },
+            Callback);
+      });
+}
+
 void swift::ide::IDEInspectionInstance::cursorInfo(
     swift::CompilerInvocation &Invocation, llvm::ArrayRef<const char *> Args,
     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
diff --git a/lib/IDETool/SyntacticMacroExpansion.cpp b/lib/IDETool/SyntacticMacroExpansion.cpp
index b5aa57afd9746..92af83ae446e6 100644
--- a/lib/IDETool/SyntacticMacroExpansion.cpp
+++ b/lib/IDETool/SyntacticMacroExpansion.cpp
@@ -425,7 +425,7 @@ void SyntacticMacroExpansionInstance::expand(
     // Attached macros.
     MacroDecl *macro = getSynthesizedMacroDecl(
         getCustomAttrName(getASTContext(), attr), expansion);
-    auto *attachedTo = expansionNode->node.get<Decl *>();
+    auto *attachedTo = cast<Decl *>(expansionNode->node);
     bufferIDs = expandAttachedMacro(macro, attr, attachedTo);
 
     // For an attached macro, remove the custom attribute; it's been fully
@@ -437,10 +437,10 @@ void SyntacticMacroExpansionInstance::expand(
     // Freestanding macros.
     FreestandingMacroExpansion *freestanding;
     auto node = expansionNode->node;
-    if (node.is<Expr *>()) {
-      freestanding = cast<MacroExpansionExpr>(node.get<Expr *>());
+    if (isa<Expr *>(node)) {
+      freestanding = cast<MacroExpansionExpr>(cast<Expr *>(node));
     } else {
-      freestanding = cast<MacroExpansionDecl>(node.get<Decl *>());
+      freestanding = cast<MacroExpansionDecl>(cast<Decl *>(node));
     }
 
     MacroDecl *macro = getSynthesizedMacroDecl(
diff --git a/lib/IRGen/CMakeLists.txt b/lib/IRGen/CMakeLists.txt
index acb64ec8b4959..e1fc4379b0dfd 100644
--- a/lib/IRGen/CMakeLists.txt
+++ b/lib/IRGen/CMakeLists.txt
@@ -17,6 +17,7 @@ add_swift_host_library(swiftIRGen STATIC
   GenClass.cpp
   GenConstant.cpp
   GenControl.cpp
+  GenCoro.cpp
   GenCoverage.cpp
   GenConcurrency.cpp
   GenDistributed.cpp
diff --git a/lib/IRGen/CallEmission.h b/lib/IRGen/CallEmission.h
index 89ac2baa265f7..0d98626fa5938 100644
--- a/lib/IRGen/CallEmission.h
+++ b/lib/IRGen/CallEmission.h
@@ -103,6 +103,7 @@ class CallEmission {
   virtual void emitCallToUnmappedExplosion(llvm::CallBase *call,
                                            Explosion &out) = 0;
   void emitYieldsToExplosion(Explosion &out);
+  void emitGuaranteedAddressToExplosion(Explosion &out);
   void setKeyPathAccessorArguments(Explosion &in, bool isOutlined,
                                    Explosion &out);
   virtual FunctionPointer getCalleeFunctionPointer() = 0;
@@ -152,11 +153,12 @@ class CallEmission {
                        WitnessMetadata *witnessMetadata);
   virtual Address getCalleeErrorSlot(SILType errorType, bool isCalleeAsync) = 0;
 
-  void addFnAttribute(llvm::Attribute::AttrKind Attr);
+  void addFnAttribute(llvm::Attribute::AttrKind kind);
 
   void setIndirectReturnAddress(Address addr) { indirectReturnAddress = addr; }
 
-  void addParamAttribute(unsigned ParamIndex, llvm::Attribute::AttrKind Attr);
+  void addParamAttribute(unsigned paramIndex, llvm::Attribute::AttrKind kind);
+  void addParamAttribute(unsigned paramIndex, llvm::Attribute attr);
 
   void emitToMemory(Address addr, const LoadableTypeInfo &substResultTI,
                     bool isOutlined);
diff --git a/lib/IRGen/ClassMetadataVisitor.h b/lib/IRGen/ClassMetadataVisitor.h
index 765121a7b5ade..ff55aa8161f03 100644
--- a/lib/IRGen/ClassMetadataVisitor.h
+++ b/lib/IRGen/ClassMetadataVisitor.h
@@ -210,7 +210,8 @@ template <class Impl> class ClassMetadataVisitor
     // whether they need them or not.
     asImpl().noteStartOfFieldOffsets(theClass);
     forEachField(IGM, theClass, [&](Field field) {
-      asImpl().addFieldEntries(field);
+      if (isExportableField(field))
+        asImpl().addFieldEntries(field);
     });
     asImpl().noteEndOfFieldOffsets(theClass);
 
diff --git a/lib/IRGen/DebugTypeInfo.cpp b/lib/IRGen/DebugTypeInfo.cpp
index 2963b075c800f..2bfd77b6ecb0d 100644
--- a/lib/IRGen/DebugTypeInfo.cpp
+++ b/lib/IRGen/DebugTypeInfo.cpp
@@ -105,8 +105,7 @@ DebugTypeInfo DebugTypeInfo::getForwardDecl(swift::Type Ty) {
   return DbgTy;
 }
 
-DebugTypeInfo DebugTypeInfo::getGlobal(SILGlobalVariable *GV,
-                                       IRGenModule &IGM) {
+static TypeBase *getTypeForGlobal(SILGlobalVariable *GV, IRGenModule &IGM) {
   // Prefer the original, potentially sugared version of the type if
   // the type hasn't been mucked with by an optimization pass.
   auto LowTy = GV->getLoweredType().getASTType();
@@ -116,6 +115,15 @@ DebugTypeInfo DebugTypeInfo::getGlobal(SILGlobalVariable *GV,
     if (DeclType->isEqual(LowTy))
       Type = DeclType.getPointer();
   }
+  // If this global variable contains an opaque type, replace it with its
+  // underlying type.
+  Type = IGM.substOpaqueTypesWithUnderlyingTypes(Type).getPointer();
+  return Type;
+}
+
+DebugTypeInfo DebugTypeInfo::getGlobal(SILGlobalVariable *GV,
+                                       IRGenModule &IGM) {
+  auto *Type = getTypeForGlobal(GV, IGM);
   auto &TI = IGM.getTypeInfoForUnlowered(Type);
   DebugTypeInfo DbgTy = getFromTypeInfo(Type, TI, IGM);
   assert(!DbgTy.isContextArchetype() &&
@@ -124,17 +132,9 @@ DebugTypeInfo DebugTypeInfo::getGlobal(SILGlobalVariable *GV,
 }
 
 DebugTypeInfo DebugTypeInfo::getGlobalFixedBuffer(SILGlobalVariable *GV,
-                                                  Size SizeInBytes,
-                                                  Alignment Align) {
-  // Prefer the original, potentially sugared version of the type if
-  // the type hasn't been mucked with by an optimization pass.
-  auto LowTy = GV->getLoweredType().getASTType();
-  auto *Type = LowTy.getPointer();
-  if (auto *Decl = GV->getDecl()) {
-    auto DeclType = Decl->getTypeInContext();
-    if (DeclType->isEqual(LowTy))
-      Type = DeclType.getPointer();
-  }
+                                                  Alignment Align,
+                                                  IRGenModule &IGM) {
+  auto *Type = getTypeForGlobal(GV, IGM);
   DebugTypeInfo DbgTy(Type, Align, ::hasDefaultAlignment(Type),
                       /* IsMetadataType = */ false, /* IsFixedBuffer = */ true);
   assert(!DbgTy.isContextArchetype() &&
diff --git a/lib/IRGen/DebugTypeInfo.h b/lib/IRGen/DebugTypeInfo.h
index 209f7aa7c1357..22236e4c82def 100644
--- a/lib/IRGen/DebugTypeInfo.h
+++ b/lib/IRGen/DebugTypeInfo.h
@@ -76,7 +76,7 @@ class DebugTypeInfo {
   /// Global variables.
   static DebugTypeInfo getGlobal(SILGlobalVariable *GV, IRGenModule &IGM);
   static DebugTypeInfo getGlobalFixedBuffer(SILGlobalVariable *GV,
-                                            Size SizeInBytes, Alignment align);
+                                            Alignment align, IRGenModule &IGM);
   /// ObjC classes.
   static DebugTypeInfo getObjCClass(ClassDecl *theClass, Size size,
                                     Alignment align);
diff --git a/lib/IRGen/EnumPayload.cpp b/lib/IRGen/EnumPayload.cpp
index f59c7e5cfdd8a..ed2967d310bcc 100644
--- a/lib/IRGen/EnumPayload.cpp
+++ b/lib/IRGen/EnumPayload.cpp
@@ -414,7 +414,7 @@ EnumPayload::emitApplyAndMask(IRGenFunction &IGF, const APInt &mask) {
       continue;
 
     // If the payload value is vacant, the mask can't change it.
-    if (pv.is<llvm::Type *>())
+    if (isa<llvm::Type *>(pv))
       continue;
 
     // If this piece is zero, it wipes out the chunk entirely, and we can
@@ -425,7 +425,7 @@ EnumPayload::emitApplyAndMask(IRGenFunction &IGF, const APInt &mask) {
     }
     
     // Otherwise, apply the mask to the existing value.
-    auto v = pv.get<llvm::Value*>();
+    auto v = cast<llvm::Value *>(pv);
     auto payloadIntTy = llvm::IntegerType::get(IGF.IGM.getLLVMContext(), size);
     auto maskConstant = llvm::ConstantInt::get(payloadIntTy, maskPiece);
     v = IGF.Builder.CreateBitOrPointerCast(v, payloadIntTy);
@@ -461,13 +461,13 @@ EnumPayload::emitApplyOrMask(IRGenModule &IGM,
     
     // If the payload value is vacant, or the mask is all ones,
     // we can adopt the mask value directly.
-    if (pv.is<llvm::Type *>() || maskPiece.isAllOnes()) {
+    if (isa<llvm::Type *>(pv) || maskPiece.isAllOnes()) {
       pv = builder.CreateBitOrPointerCast(maskConstant, payloadTy);
       continue;
     }
-    
+
     // Otherwise, apply the mask to the existing value.
-    auto v = pv.get<llvm::Value*>();
+    auto v = cast<llvm::Value *>(pv);
     v = builder.CreateBitOrPointerCast(v, payloadIntTy);
     v = builder.CreateOr(v, maskConstant);
     v = builder.CreateBitOrPointerCast(v, payloadTy);
@@ -488,18 +488,16 @@ EnumPayload::emitApplyOrMask(IRGenFunction &IGF,
 
     auto payloadIntTy = llvm::IntegerType::get(IGF.IGM.getLLVMContext(), size);
 
-    if (mask.PayloadValues[i].is<llvm::Type *>()) {
+    if (isa<llvm::Type *>(mask.PayloadValues[i])) {
       // We're ORing with zero, do nothing
-    } else if (PayloadValues[i].is<llvm::Type *>()) {
+    } else if (isa<llvm::Type *>(PayloadValues[i])) {
       PayloadValues[i] = mask.PayloadValues[i];
     } else {
       auto v1 = IGF.Builder.CreateBitOrPointerCast(
-          PayloadValues[i].get<llvm::Value *>(),
-          payloadIntTy);
+          cast<llvm::Value *>(PayloadValues[i]), payloadIntTy);
 
       auto v2 = IGF.Builder.CreateBitOrPointerCast(
-          mask.PayloadValues[i].get<llvm::Value *>(),
-          payloadIntTy);
+          cast<llvm::Value *>(mask.PayloadValues[i]), payloadIntTy);
 
       PayloadValues[i] = IGF.Builder.CreateBitOrPointerCast(
           IGF.Builder.CreateOr(v1, v2),
@@ -584,7 +582,7 @@ EnumPayload::emitGatherSpareBits(IRGenFunction &IGF,
     // If this value is zero, it has nothing to add to the spare bits.
     auto v = pv.dyn_cast<llvm::Value*>();
     if (!v) {
-      spareBitReader.skip(DL.getTypeSizeInBits(pv.get<llvm::Type*>()));
+      spareBitReader.skip(DL.getTypeSizeInBits(cast<llvm::Type *>(pv)));
       continue;
     }
 
@@ -644,7 +642,7 @@ void EnumPayload::print(llvm::raw_ostream &OS) {
       v->print(OS);
       OS << '\n';
     } else {
-      auto *t = pv.get<llvm::Type*>();
+      auto *t = cast<llvm::Type *>(pv);
       OS << "type: ";
       t->print(OS);
       OS << '\n';
diff --git a/lib/IRGen/Field.h b/lib/IRGen/Field.h
index 0b6eba19a2a53..85b977ad7cc1f 100644
--- a/lib/IRGen/Field.h
+++ b/lib/IRGen/Field.h
@@ -96,12 +96,20 @@ struct Field {
   bool operator!=(Field other) const { return declOrKind != other.declOrKind; }
 };
 
+// Don't export private C++ fields that were imported as private Swift fields.
+// The type of a private field might not have all the type witness operations
+// that Swift requires, for instance, `std::unique_ptr<IncompleteType>` would
+// not have a destructor.
+bool isExportableField(Field field);
+
 /// Iterate all the fields of the given struct or class type, including
 /// any implicit fields that might be accounted for in
 /// getFieldVectorLength.
 void forEachField(IRGenModule &IGM, const NominalTypeDecl *typeDecl,
                   llvm::function_ref<void(Field field)> fn);
 
+unsigned countExportableFields(IRGenModule &IGM, const NominalTypeDecl *type);
+
 } // end namespace irgen
 } // end namespace swift
 
diff --git a/lib/IRGen/Fulfillment.cpp b/lib/IRGen/Fulfillment.cpp
index a75569bfe0647..13cce27cc03a8 100644
--- a/lib/IRGen/Fulfillment.cpp
+++ b/lib/IRGen/Fulfillment.cpp
@@ -178,35 +178,44 @@ bool FulfillmentMap::searchTypeMetadata(IRGenModule &IGM, CanType type,
                                      source, std::move(path), keys);
   }
 
-  if (auto tupleType = dyn_cast<TupleType>(type)) {
-    if (tupleType->getNumElements() == 1 &&
-        isa<PackExpansionType>(tupleType.getElementType(0))) {
-
-      bool hadFulfillment = false;
-      auto packType = tupleType.getInducedPackType();
-
-      {
-        auto argPath = path;
-        argPath.addTuplePackComponent();
-        hadFulfillment |= searchTypeMetadataPack(IGM, packType,
-                                                 isExact, metadataState, source,
-                                                 std::move(argPath), keys);
-      }
+  // TODO: functions
+  // TODO: metatypes
 
-      {
-        auto argPath = path;
-        argPath.addTupleShapeComponent();
-        hadFulfillment |= searchShapeRequirement(IGM, packType, source,
-                                                 std::move(argPath));
+  return false;
+}
 
-      }
+/// Metadata fulfillment in a tuple conformance witness thunks.
+///
+/// \return true if any fulfillments were added by this search.
+bool FulfillmentMap::searchTupleTypeMetadata(IRGenModule &IGM, CanTupleType tupleType,
+                                             IsExact_t isExact,
+                                             MetadataState metadataState,
+                                             unsigned source, MetadataPath &&path,
+                                             const InterestingKeysCallback &keys) {
+  if (tupleType->getNumElements() == 1 &&
+      isa<PackExpansionType>(tupleType.getElementType(0))) {
 
-      return hadFulfillment;
+    bool hadFulfillment = false;
+    auto packType = tupleType.getInducedPackType();
+
+    {
+      auto argPath = path;
+      argPath.addTuplePackComponent();
+      hadFulfillment |= searchTypeMetadataPack(IGM, packType,
+                                               isExact, metadataState, source,
+                                               std::move(argPath), keys);
     }
-  }
 
-  // TODO: functions
-  // TODO: metatypes
+    {
+      auto argPath = path;
+      argPath.addTupleShapeComponent();
+      hadFulfillment |= searchShapeRequirement(IGM, packType, source,
+                                               std::move(argPath));
+
+    }
+
+    return hadFulfillment;
+  }
 
   return false;
 }
diff --git a/lib/IRGen/Fulfillment.h b/lib/IRGen/Fulfillment.h
index 7fe9427b01af1..e1d63a722db28 100644
--- a/lib/IRGen/Fulfillment.h
+++ b/lib/IRGen/Fulfillment.h
@@ -102,6 +102,14 @@ class FulfillmentMap {
                           unsigned sourceIndex, MetadataPath &&path,
                           const InterestingKeysCallback &interestingKeys);
 
+  /// Metadata fulfillment in tuple conformance witness thunks.
+  ///
+  /// \return true if any fulfillments were added by this search.
+  bool searchTupleTypeMetadata(IRGenModule &IGM, CanTupleType type, IsExact_t isExact,
+                               MetadataState metadataState,
+                               unsigned sourceIndex, MetadataPath &&path,
+                               const InterestingKeysCallback &interestingKeys);
+
   /// Search the given type metadata pack for useful fulfillments.
   ///
   /// \return true if any fulfillments were added by this search.
diff --git a/lib/IRGen/GenArchetype.cpp b/lib/IRGen/GenArchetype.cpp
index e0428798a385b..bb45efbfec026 100644
--- a/lib/IRGen/GenArchetype.cpp
+++ b/lib/IRGen/GenArchetype.cpp
@@ -103,10 +103,10 @@ irgen::emitArchetypeTypeMetadataRef(IRGenFunction &IGF,
   auto parent = cast<ArchetypeType>(
     archetype->getGenericEnvironment()->mapTypeIntoContext(
       member->getBase())->getCanonicalType());
-  AssociatedType association(member->getAssocType());
+  auto *assocType = member->getAssocType();
 
   MetadataResponse response =
-    emitAssociatedTypeMetadataRef(IGF, parent, association, request);
+    emitAssociatedTypeMetadataRef(IGF, parent, assocType, request);
 
   setTypeMetadataName(IGF.IGM, response.getMetadata(), archetype);
 
@@ -321,11 +321,11 @@ llvm::Value *irgen::emitArchetypeWitnessTableRef(IRGenFunction &IGF,
 MetadataResponse
 irgen::emitAssociatedTypeMetadataRef(IRGenFunction &IGF,
                                      CanArchetypeType origin,
-                                     AssociatedType association,
+                                     AssociatedTypeDecl *assocType,
                                      DynamicMetadataRequest request) {
   // Find the conformance of the origin to the associated type's protocol.
   llvm::Value *wtable = emitArchetypeWitnessTableRef(IGF, origin,
-                                               association.getSourceProtocol());
+                                               assocType->getProtocol());
 
   // Find the origin's type metadata.
   llvm::Value *originMetadata =
@@ -333,7 +333,7 @@ irgen::emitAssociatedTypeMetadataRef(IRGenFunction &IGF,
       .getMetadata();
 
   return emitAssociatedTypeMetadataRef(IGF, originMetadata, wtable,
-                                       association, request);
+                                       assocType, request);
 }
 
 const TypeInfo *TypeConverter::convertArchetypeType(ArchetypeType *archetype) {
diff --git a/lib/IRGen/GenArchetype.h b/lib/IRGen/GenArchetype.h
index 929fda6fd1a0c..958c8c89ecc7d 100644
--- a/lib/IRGen/GenArchetype.h
+++ b/lib/IRGen/GenArchetype.h
@@ -25,7 +25,7 @@ namespace llvm {
 }
 
 namespace swift {
-  class AssociatedType;
+  class AssociatedTypeDecl;
   class ProtocolDecl;
   class SILType;
 
@@ -51,7 +51,7 @@ namespace irgen {
   /// Emit a metadata reference for an associated type of an archetype.
   MetadataResponse emitAssociatedTypeMetadataRef(IRGenFunction &IGF,
                                                  CanArchetypeType origin,
-                                                 AssociatedType association,
+                                                 AssociatedTypeDecl *assocType,
                                                  DynamicMetadataRequest request);
 
   /// Emit a dynamic metatype lookup for the given archetype.
diff --git a/lib/IRGen/GenArray.cpp b/lib/IRGen/GenArray.cpp
index 354ee8bfbf6a4..b95766f74e5e7 100644
--- a/lib/IRGen/GenArray.cpp
+++ b/lib/IRGen/GenArray.cpp
@@ -53,8 +53,15 @@ class ArrayTypeInfoBase : public BaseTypeInfo {
       return;
     }
     if (fixedSize == 1) {
-      // only one element to operate on
-      return body(addrs);
+      auto zero = llvm::ConstantInt::get(IGF.IGM.IntPtrTy, 0);
+      // only one element to operate on; index to it in each array
+      SmallVector<Address, 2> eltAddrs;
+      eltAddrs.reserve(addrs.size());
+      for (auto index : indices(addrs)) {
+        eltAddrs.push_back(Element.indexArray(IGF, addrs[index], zero,
+                                              getElementSILType(IGF.IGM, T)));
+      }
+      return body(eltAddrs);
     }
     
     auto arraySize = getArraySize(IGF, T);
@@ -173,6 +180,14 @@ class ArrayTypeInfoBase : public BaseTypeInfo {
                           Element.destroy(IGF, elt[0], eltTy, isOutlined);
                         }, {address});
   }
+
+  void collectMetadataForOutlining(OutliningMetadataCollector &collector,
+                                   SILType T) const override {
+    auto &IGM = collector.IGF.IGM;
+    auto elementTy = getElementSILType(IGM, T);
+    IGM.getTypeInfo(elementTy).collectMetadataForOutlining(collector,
+                                                           elementTy);
+  }
 };
 
 template<typename BaseTypeInfo>
@@ -233,9 +248,15 @@ class FixedArrayTypeInfoBase : public ArrayTypeInfoBase<BaseTypeInfo> {
     
     // Take spare bits from the first element only.
     SpareBitVector result = elementTI.getSpareBits();
+
     // We can use the padding to the next element as spare bits too.
-    result.appendSetBits(getArraySize(arraySize, elementTI).getValueInBits()
-                           - result.size());
+    auto padding = elementTI.getFixedStride() - elementTI.getFixedSize();
+    result.appendSetBits(padding.getValueInBits());
+
+    // spare bits of any other elements should not be considered
+    result.appendClearBits(
+        getArraySize(arraySize - 1, elementTI).getValueInBits());
+
     return result;
   }
   
diff --git a/lib/IRGen/GenBuiltin.cpp b/lib/IRGen/GenBuiltin.cpp
index d23852cd6a9e3..b2d38181012da 100644
--- a/lib/IRGen/GenBuiltin.cpp
+++ b/lib/IRGen/GenBuiltin.cpp
@@ -133,6 +133,8 @@ getMaximallyAbstractedLoweredTypeAndTypeInfo(IRGenModule &IGM, Type unloweredTyp
 void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
                             BuiltinInst *Inst, ArrayRef<SILType> argTypes,
                             Explosion &args, Explosion &out) {
+  auto &IGM = IGF.IGM;
+
   Identifier FnId = Inst->getName();
   SILType resultType = Inst->getType();
   SubstitutionMap substitutions = Inst->getSubstitutions();
@@ -444,9 +446,9 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
     SmallVector<llvm::Type*, 4> ArgTys;
     for (auto T : IInfo.Types)
       ArgTys.push_back(IGF.IGM.getStorageTypeForLowered(T->getCanonicalType()));
-      
-    auto F = llvm::Intrinsic::getDeclaration(&IGF.IGM.Module,
-                                             (llvm::Intrinsic::ID)IID, ArgTys);
+
+    auto F = llvm::Intrinsic::getOrInsertDeclaration(
+        &IGF.IGM.Module, (llvm::Intrinsic::ID)IID, ArgTys);
     llvm::FunctionType *FT = F->getFunctionType();
     SmallVector<llvm::Value*, 8> IRArgs;
     for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
@@ -512,7 +514,7 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
     SmallVector<llvm::Type *, 2> ArgTys;                                       \
     auto opType = Builtin.Types[0]->getCanonicalType();                        \
     ArgTys.push_back(IGF.IGM.getStorageTypeForLowered(opType));                \
-    auto F = llvm::Intrinsic::getDeclaration(                                  \
+    auto F = llvm::Intrinsic::getOrInsertDeclaration(                          \
         &IGF.IGM.Module, getLLVMIntrinsicIDForBuiltinWithOverflow(Builtin.ID), \
         ArgTys);                                                               \
     SmallVector<llvm::Value *, 2> IRArgs;                                      \
@@ -588,9 +590,7 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
   }
   
   if (Builtin.ID == BuiltinValueKind::FNeg) {
-    llvm::Value *rhs = args.claimNext();
-    llvm::Value *lhs = llvm::ConstantFP::get(rhs->getType(), "-0.0");
-    llvm::Value *v = IGF.Builder.CreateFSub(lhs, rhs);
+    llvm::Value *v = IGF.Builder.CreateFNeg(args.claimNext());
     return out.add(v);
   }
   if (Builtin.ID == BuiltinValueKind::AssumeTrue) {
@@ -602,8 +602,8 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
   }
   if (Builtin.ID == BuiltinValueKind::AssumeNonNegative) {
     llvm::Value *v = args.claimNext();
-    // Set a value range on the load instruction, which must be the argument of
-    // the builtin.
+    // If the argument is a `load` or `call` we can use a range metadata to
+    // specify the >= 0 constraint.
     if (isa<llvm::LoadInst>(v) || isa<llvm::CallInst>(v)) {
       // The load must be post-dominated by the builtin. Otherwise we would get
       // a wrong assumption in the else-branch in this example:
@@ -628,6 +628,10 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
         llvm::MDNode *range = llvm::MDNode::get(ctx, rangeElems);
         I->setMetadata(llvm::LLVMContext::MD_range, range);
       }
+    } else {
+      // Otherwise, we specify the constraint with an `llvm.assume` intrinsic.
+      auto *cmp = IGF.Builder.CreateICmpSGE(v, llvm::ConstantInt::get(v->getType(), 0));
+      IGF.Builder.CreateIntrinsicCall(llvm::Intrinsic::assume, cmp);
     }
     // Don't generate any code for the builtin.
     return out.add(v);
@@ -730,8 +734,7 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
       newval = IGF.Builder.CreatePtrToInt(newval, IGF.IGM.IntPtrTy);
     }
 
-    pointer = IGF.Builder.CreateBitCast(pointer,
-                                  llvm::PointerType::getUnqual(cmp->getType()));
+    pointer = IGF.Builder.CreateBitCast(pointer, IGM.PtrTy);
     llvm::Value *value = IGF.Builder.CreateAtomicCmpXchg(
         pointer, cmp, newval, llvm::MaybeAlign(),
         successOrdering, failureOrdering,
@@ -799,8 +802,7 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
     if (origTy->isPointerTy())
       val = IGF.Builder.CreatePtrToInt(val, IGF.IGM.IntPtrTy);
 
-    pointer = IGF.Builder.CreateBitCast(pointer,
-                                  llvm::PointerType::getUnqual(val->getType()));
+    pointer = IGF.Builder.CreateBitCast(pointer, IGM.PtrTy);
     llvm::Value *value = IGF.Builder.CreateAtomicRMW(
         SubOpcode, pointer, val, llvm::MaybeAlign(), ordering,
         isSingleThread ? llvm::SyncScope::SingleThread
@@ -851,7 +853,7 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
                                        valueTy->getPrimitiveSizeInBits());
     }
 
-    pointer = IGF.Builder.CreateBitCast(pointer, valueTy->getPointerTo());
+    pointer = IGF.Builder.CreateBitCast(pointer, IGM.PtrTy);
 
     if (Builtin.ID == BuiltinValueKind::AtomicLoad) {
       auto load = IGF.Builder.CreateLoad(pointer, valueTy,
@@ -899,6 +901,16 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
     return;
   }
   
+  if (Builtin.ID == BuiltinValueKind::Select) {
+    using namespace llvm;
+    
+    auto pred = args.claimNext();
+    auto ifTrue = args.claimNext();
+    auto ifFalse = args.claimNext();
+    out.add(IGF.Builder.CreateSelect(pred, ifTrue, ifFalse));
+    return;
+  }
+  
   if (Builtin.ID == BuiltinValueKind::ShuffleVector) {
     using namespace llvm;
 
@@ -908,6 +920,47 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
     out.add(IGF.Builder.CreateShuffleVector(dict0, dict1, index));
     return;
   }
+  
+  if (Builtin.ID == BuiltinValueKind::Interleave) {
+    using namespace llvm;
+    
+    auto src0 = args.claimNext();
+    auto src1 = args.claimNext();
+    
+    int n = Builtin.Types[0]->getAs<BuiltinVectorType>()->getNumElements();
+    SmallVector<int> shuffleLo(n);
+    SmallVector<int> shuffleHi(n);
+    for (int i=0; i<n/2; ++i) {
+      shuffleLo[2*i] = i;
+      shuffleHi[2*i] = n/2 + i;
+      shuffleLo[2*i+1] = n + i;
+      shuffleHi[2*i+1] = 3*n/2 + i;
+    }
+    
+    out.add(IGF.Builder.CreateShuffleVector(src0, src1, shuffleLo));
+    out.add(IGF.Builder.CreateShuffleVector(src0, src1, shuffleHi));
+    return;
+  }
+  
+  
+  if (Builtin.ID == BuiltinValueKind::Deinterleave) {
+    using namespace llvm;
+    
+    auto src0 = args.claimNext();
+    auto src1 = args.claimNext();
+    
+    int n = Builtin.Types[0]->getAs<BuiltinVectorType>()->getNumElements();
+    SmallVector<int> shuffleEven(n);
+    SmallVector<int> shuffleOdd(n);
+    for (int i=0; i<n; ++i) {
+      shuffleEven[i] = 2*i;
+      shuffleOdd[i]  = 2*i + 1;
+    }
+    
+    out.add(IGF.Builder.CreateShuffleVector(src0, src1, shuffleEven));
+    out.add(IGF.Builder.CreateShuffleVector(src0, src1, shuffleOdd));
+    return;
+  }
 
   if (Builtin.ID == BuiltinValueKind::SToSCheckedTrunc ||
       Builtin.ID == BuiltinValueKind::UToUCheckedTrunc ||
@@ -1012,8 +1065,8 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
       || Builtin.ID == BuiltinValueKind::OnceWithContext) {
     // The input type is statically (Builtin.RawPointer, @convention(thin) () -> ()).
     llvm::Value *PredPtr = args.claimNext();
-    // Cast the predicate to a OnceTy pointer.
-    PredPtr = IGF.Builder.CreateBitCast(PredPtr, IGF.IGM.OnceTy->getPointerTo());
+    // Cast the predicate to a pointer.
+    PredPtr = IGF.Builder.CreateBitCast(PredPtr, IGM.PtrTy);
     llvm::Value *FnCode = args.claimNext();
     // Get the context if any.
     llvm::Value *Context;
@@ -1104,9 +1157,8 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
           IsTriviallyDestroyable)
         return;
 
-      llvm::Value *firstElem =
-          IGF.Builder.CreatePtrToInt(IGF.Builder.CreateBitCast(
-              ptr, elemTI.getStorageType()->getPointerTo()), IGF.IGM.IntPtrTy);
+      llvm::Value *firstElem = IGF.Builder.CreatePtrToInt(
+          IGF.Builder.CreateBitCast(ptr, IGM.PtrTy), IGF.IGM.IntPtrTy);
 
       auto *origBB = IGF.Builder.GetInsertBlock();
       auto *headerBB = IGF.createBasicBlock("loop_header");
@@ -1124,8 +1176,7 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
       llvm::Value *offset =
           IGF.Builder.CreateMul(phi, elemTI.getStaticStride(IGF.IGM));
       llvm::Value *added = IGF.Builder.CreateAdd(firstElem, offset);
-      llvm::Value *addr = IGF.Builder.CreateIntToPtr(
-          added, elemTI.getStorageType()->getPointerTo());
+      llvm::Value *addr = IGF.Builder.CreateIntToPtr(added, IGM.PtrTy);
 
       bool isOutlined = false;
       elemTI.destroy(IGF, elemTI.getAddressForPointer(addr), elemTy,
@@ -1140,8 +1191,7 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
       return;
     }
 
-    ptr = IGF.Builder.CreateBitCast(ptr,
-                              valueTy.second.getStorageType()->getPointerTo());
+    ptr = IGF.Builder.CreateBitCast(ptr, IGM.PtrTy);
     Address array = valueTy.second.getAddressForPointer(ptr);
 
     // If the count is statically known to be a constant 1, then just call the
@@ -1193,13 +1243,9 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
       }
 
       llvm::Value *firstSrcElem = IGF.Builder.CreatePtrToInt(
-          IGF.Builder.CreateBitCast(src,
-                                    elemTI.getStorageType()->getPointerTo()),
-          IGF.IGM.IntPtrTy);
+          IGF.Builder.CreateBitCast(src, IGM.PtrTy), IGF.IGM.IntPtrTy);
       llvm::Value *firstDestElem = IGF.Builder.CreatePtrToInt(
-          IGF.Builder.CreateBitCast(dest,
-                                    elemTI.getStorageType()->getPointerTo()),
-          IGF.IGM.IntPtrTy);
+          IGF.Builder.CreateBitCast(dest, IGM.PtrTy), IGF.IGM.IntPtrTy);
 
       auto *origBB = IGF.Builder.GetInsertBlock();
       auto *headerBB = IGF.createBasicBlock("loop_header");
@@ -1231,11 +1277,9 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
            IGF.Builder.CreateMul(idx, elemTI.getStaticStride(IGF.IGM));
 
       llvm::Value *srcAdded = IGF.Builder.CreateAdd(firstSrcElem, offset);
-      auto *srcElem = IGF.Builder.CreateIntToPtr(
-          srcAdded, elemTI.getStorageType()->getPointerTo());
+      auto *srcElem = IGF.Builder.CreateIntToPtr(srcAdded, IGM.PtrTy);
       llvm::Value *dstAdded = IGF.Builder.CreateAdd(firstDestElem, offset);
-      auto *destElem = IGF.Builder.CreateIntToPtr(
-          dstAdded, elemTI.getStorageType()->getPointerTo());
+      auto *destElem = IGF.Builder.CreateIntToPtr(dstAdded, IGM.PtrTy);
 
       Address destAddr = elemTI.getAddressForPointer(destElem);
       Address srcAddr = elemTI.getAddressForPointer(srcElem);
@@ -1273,11 +1317,9 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
 
     auto valueTy = getLoweredTypeAndTypeInfo(IGF.IGM,
                                              substitutions.getReplacementTypes()[0]);
-    
-    dest = IGF.Builder.CreateBitCast(dest,
-                               valueTy.second.getStorageType()->getPointerTo());
-    src = IGF.Builder.CreateBitCast(src,
-                               valueTy.second.getStorageType()->getPointerTo());
+
+    dest = IGF.Builder.CreateBitCast(dest, IGM.PtrTy);
+    src = IGF.Builder.CreateBitCast(src, IGM.PtrTy);
     Address destArray = valueTy.second.getAddressForPointer(dest);
     Address srcArray = valueTy.second.getAddressForPointer(src);
     
@@ -1345,7 +1387,13 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
     }
     return;
   }
-  
+
+  if (Builtin.ID == BuiltinValueKind::PrepareInitialization) {
+    ASSERT(args.size() > 0 && "only address-variant of prepareInitialization is supported");
+    (void)args.claimNext();
+    return;
+  }
+
   if (Builtin.ID == BuiltinValueKind::GetObjCTypeEncoding) {
     (void)args.claimAll();
     Type valueTy = substitutions.getReplacementTypes()[0];
@@ -1353,8 +1401,9 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
     auto clangTy = IGF.IGM.getClangType(valueTy->getCanonicalType());
     std::string encoding;
     IGF.IGM.getClangASTContext().getObjCEncodingForType(clangTy, encoding);
-    
-    auto globalString = IGF.IGM.getAddrOfGlobalString(encoding);
+
+    auto globalString = IGF.IGM.getAddrOfGlobalString(
+        encoding, CStringSectionType::ObjCMethodType);
     out.add(globalString);
     return;
   }
diff --git a/lib/IRGen/GenCall.cpp b/lib/IRGen/GenCall.cpp
index 8a5a9139c99c1..5ba66e465d910 100644
--- a/lib/IRGen/GenCall.cpp
+++ b/lib/IRGen/GenCall.cpp
@@ -262,10 +262,14 @@ llvm::CallInst *IRGenFunction::emitSuspendAsyncCall(
     llvm::Function *projectFn = cast<llvm::Function>(
         (cast<llvm::Constant>(args[2])->stripPointerCasts()));
     auto *fnTy = projectFn->getFunctionType();
-
-    llvm::Value *context =
+    llvm::Value *callerContext = nullptr;
+    if (projectFn == getOrCreateResumePrjFn()) {
+      callerContext = popAsyncContext(calleeContext);
+    } else {
+      callerContext =
         Builder.CreateCallWithoutDbgLoc(fnTy, projectFn, {calleeContext});
-    storeCurrentAsyncContext(context);
+    }
+    storeCurrentAsyncContext(callerContext);
   }
 
   return id;
@@ -305,14 +309,15 @@ static void addDereferenceableAttributeToBuilder(IRGenModule &IGM,
 static void addIndirectValueParameterAttributes(IRGenModule &IGM,
                                                 llvm::AttributeList &attrs,
                                                 const TypeInfo &ti,
-                                                unsigned argIndex) {
+                                                unsigned argIndex,
+                                                bool addressable) {
   llvm::AttrBuilder b(IGM.getLLVMContext());
   // Value parameter pointers can't alias or be captured.
   b.addAttribute(llvm::Attribute::NoAlias);
   // Bitwise takable value types are guaranteed not to capture
   // a pointer into itself.
-  if (ti.isBitwiseTakable(ResilienceExpansion::Maximal))
-    b.addAttribute(llvm::Attribute::NoCapture);
+  if (!addressable && ti.isBitwiseTakable(ResilienceExpansion::Maximal))
+    b.addCapturesAttr(llvm::CaptureInfo::none());
   // The parameter must reference dereferenceable memory of the type.
   addDereferenceableAttributeToBuilder(IGM, b, ti);
 
@@ -325,7 +330,7 @@ static void addPackParameterAttributes(IRGenModule &IGM,
                                        unsigned argIndex) {
   llvm::AttrBuilder b(IGM.getLLVMContext());
   // Pack parameter pointers can't alias.
-  // Note: they are not marked `nocapture` as one
+  // Note: they are not marked `captures(none)` as one
   // pack parameter could be a value type (e.g. a C++ type)
   // that captures its own pointer in itself.
   b.addAttribute(llvm::Attribute::NoAlias);
@@ -340,7 +345,7 @@ static void addPackParameterAttributes(IRGenModule &IGM,
 static void addInoutParameterAttributes(IRGenModule &IGM, SILType paramSILType,
                                         llvm::AttributeList &attrs,
                                         const TypeInfo &ti, unsigned argIndex,
-                                        bool aliasable) {
+                                        bool aliasable, bool addressable) {
   llvm::AttrBuilder b(IGM.getLLVMContext());
   // Thanks to exclusivity checking, it is not possible to alias inouts except
   // those that are inout_aliasable.
@@ -351,8 +356,8 @@ static void addInoutParameterAttributes(IRGenModule &IGM, SILType paramSILType,
   }
   // Bitwise takable value types are guaranteed not to capture
   // a pointer into itself.
-  if (ti.isBitwiseTakable(ResilienceExpansion::Maximal))
-    b.addAttribute(llvm::Attribute::NoCapture);
+  if (!addressable && ti.isBitwiseTakable(ResilienceExpansion::Maximal))
+    b.addCapturesAttr(llvm::CaptureInfo::none());
   // The inout must reference dereferenceable memory of the type.
   addDereferenceableAttributeToBuilder(IGM, b, ti);
 
@@ -406,7 +411,7 @@ static void addIndirectResultAttributes(IRGenModule &IGM,
   // Bitwise takable value types are guaranteed not to capture
   // a pointer into itself.
   if (typeInfo.isBitwiseTakable(ResilienceExpansion::Maximal))
-    b.addAttribute(llvm::Attribute::NoCapture);
+    b.addCapturesAttr(llvm::CaptureInfo::none());
   if (allowSRet) {
     assert(storageType);
     b.addStructRetAttr(storageType);
@@ -525,7 +530,7 @@ void IRGenModule::addSwiftErrorAttributes(llvm::AttributeList &attrs,
   // The error result should not be aliased, captured, or pointed at invalid
   // addresses regardless.
   b.addAttribute(llvm::Attribute::NoAlias);
-  b.addAttribute(llvm::Attribute::NoCapture);
+  b.addCapturesAttr(llvm::CaptureInfo::none());
   b.addDereferenceableAttr(getPointerSize().getValue());
 
   attrs = attrs.addParamAttributes(this->getLLVMContext(), argIndex, b);
@@ -586,6 +591,10 @@ namespace {
     /// function type.
     void expandCoroutineContinuationType();
 
+    /// Initializes the result type for functions with @guaranteed_addr return
+    /// convention.
+    void expandGuaranteedAddressResult();
+
     // Expand the components for the async continuation entrypoint of the
     // function type (the function to be called on returning).
     void expandAsyncReturnType();
@@ -600,9 +609,11 @@ namespace {
     Signature getSignature();
 
   private:
-    const TypeInfo &expand(SILParameterInfo param);
+    const TypeInfo &expand(unsigned paramIdx);
     llvm::Type *addIndirectResult(SILType resultType, bool useInReg = false);
 
+    bool isAddressableParam(unsigned paramIdx);
+
     SILFunctionConventions getSILFuncConventions() const {
       return SILFunctionConventions(FnType, IGM.getSILModule());
     }
@@ -632,9 +643,7 @@ namespace {
     }
 
     /// Add a pointer to the given type as the next parameter.
-    void addPointerParameter(llvm::Type *storageType) {
-      ParamIRTypes.push_back(storageType->getPointerTo());
-    }
+    void addOpaquePointerParameter() { ParamIRTypes.push_back(IGM.PtrTy); }
 
     void addCoroutineContextParameter();
     void addCoroutineAllocatorParameter();
@@ -667,7 +676,7 @@ llvm::Type *SignatureExpansion::addIndirectResult(SILType resultType,
   auto storageTy = resultTI.getStorageType();
   addIndirectResultAttributes(IGM, Attrs, ParamIRTypes.size(), claimSRet(),
                               storageTy, resultTI, useInReg);
-  addPointerParameter(storageTy);
+  addOpaquePointerParameter();
   return IGM.VoidTy;
 }
 
@@ -689,6 +698,10 @@ void SignatureExpansion::expandResult(
 
   auto fnConv = getSILFuncConventions();
 
+  if (fnConv.hasGuaranteedAddressResult()) {
+    return expandGuaranteedAddressResult();
+  }
+
   // Disable the use of sret if we have multiple indirect results.
   if (fnConv.getNumIndirectSILResults() > 1)
     CanUseSRet = false;
@@ -742,7 +755,7 @@ void SignatureExpansion::expandIndirectResults() {
     }
     addIndirectResultAttributes(IGM, Attrs, ParamIRTypes.size(), useSRet,
                                 storageTy, typeInfo);
-    addPointerParameter(storageTy);
+    addOpaquePointerParameter();
   }
 }
 
@@ -780,9 +793,9 @@ namespace {
     /// Is the yielded value formally indirect?
     bool isFormalIndirect() const { return YieldTy.isAddress(); }
 
-    llvm::PointerType *getIndirectPointerType() const {
+    llvm::PointerType *getIndirectPointerType(IRGenModule &IGM) const {
       assert(isIndirect());
-      return YieldTI.getStorageType()->getPointerTo();
+      return IGM.PtrTy;
     }
 
     const NativeConventionSchema &getDirectSchema() const {
@@ -842,7 +855,7 @@ void SignatureExpansion::expandCoroutineResult(bool forContinuation) {
 
     // If the individual value must be yielded indirectly, add a pointer.
     if (schema.isIndirect()) {
-      components.push_back(schema.getIndirectPointerType());
+      components.push_back(schema.getIndirectPointerType(IGM));
       continue;
     }
 
@@ -884,7 +897,7 @@ void SignatureExpansion::expandCoroutineResult(bool forContinuation) {
     // trusting LLVM's?
     CoroInfo.indirectResultsType =
         llvm::StructType::get(IGM.getLLVMContext(), overflowTypes);
-    components.back() = CoroInfo.indirectResultsType->getPointerTo();
+    components.back() = IGM.PtrTy;
   }
 
   ResultIRType = components.size() == 1
@@ -906,6 +919,11 @@ void SignatureExpansion::expandCoroutineContinuationParameters() {
   }
 }
 
+void SignatureExpansion::expandGuaranteedAddressResult() {
+  CanUseSRet = false;
+  ResultIRType = IGM.PtrTy;
+}
+
 void SignatureExpansion::addAsyncParameters() {
   // using TaskContinuationFunction =
   //   SWIFT_CC(swift)
@@ -1206,6 +1224,8 @@ namespace {
       }
 
       case clang::Type::ArrayParameter:
+      case clang::Type::HLSLAttributedResource:
+      case clang::Type::HLSLInlineSpirv:
         llvm_unreachable("HLSL type in ABI lowering");
 
 
@@ -1314,7 +1334,7 @@ namespace {
 
       // We should never see ARM SVE types at all.
 #define SVE_TYPE(Name, Id, ...) case clang::BuiltinType::Id:
-#include "clang/Basic/AArch64SVEACLETypes.def"
+#include "clang/Basic/AArch64ACLETypes.def"
         llvm_unreachable("ARM SVE type in ABI lowering");
 
       // We should never see PPC MMA types at all.
@@ -1336,6 +1356,11 @@ namespace {
 #include "clang/Basic/AMDGPUTypes.def"
         llvm_unreachable("AMDGPU type in ABI lowering");
 
+      // We should never see HLSL intangible types at all.
+#define HLSL_INTANGIBLE_TYPE(Name, Id, ...) case clang::BuiltinType::Id:
+#include "clang/Basic/HLSLIntangibleTypes.def"
+        llvm_unreachable("HLSL intangible type in ABI lowering");
+
       // Handle all the integer types as opaque values.
 #define BUILTIN_TYPE(Id, SingletonId)
 #define SIGNED_TYPE(Id, SingletonId) \
@@ -1677,6 +1702,9 @@ void SignatureExpansion::expandExternalSignatureTypes() {
                                     paramTI.getStorageType(), paramTI);
         break;
       }
+      case clang::ParameterABI::HLSLOut:
+      case clang::ParameterABI::HLSLInOut:
+        llvm_unreachable("not implemented");
       }
 
       // If the coercion type is a struct which can be flattened, we need to
@@ -1717,7 +1745,7 @@ void SignatureExpansion::expandExternalSignatureTypes() {
             Alignment(AI.getIndirectAlign().getQuantity()),
             paramTI.getStorageType());
       }
-      addPointerParameter(paramTI.getStorageType());
+      addOpaquePointerParameter();
       break;
     }
     case clang::CodeGen::ABIArgInfo::Expand:
@@ -1781,7 +1809,8 @@ static ArrayRef<llvm::Type *> expandScalarOrStructTypeToArray(llvm::Type *&ty) {
   return expandedTys;
 }
 
-const TypeInfo &SignatureExpansion::expand(SILParameterInfo param) {
+const TypeInfo &SignatureExpansion::expand(unsigned paramIdx) {
+  auto param = FnType->getParameters()[paramIdx];
   auto paramSILType = getSILFuncConventions().getSILType(
       param, IGM.getMaximalTypeExpansionContext());
   auto &ti = IGM.getTypeInfo(paramSILType);
@@ -1789,25 +1818,25 @@ const TypeInfo &SignatureExpansion::expand(SILParameterInfo param) {
   case ParameterConvention::Indirect_In:
   case ParameterConvention::Indirect_In_Guaranteed:
   case ParameterConvention::Indirect_In_CXX:
-    addIndirectValueParameterAttributes(IGM, Attrs, ti, ParamIRTypes.size());
-    addPointerParameter(IGM.getStorageType(getSILFuncConventions().getSILType(
-        param, IGM.getMaximalTypeExpansionContext())));
+    addIndirectValueParameterAttributes(IGM, Attrs, ti, ParamIRTypes.size(),
+                                        isAddressableParam(paramIdx));
+    addOpaquePointerParameter();
     return ti;
 
   case ParameterConvention::Indirect_Inout:
   case ParameterConvention::Indirect_InoutAliasable:
     addInoutParameterAttributes(
-        IGM, paramSILType, Attrs, ti, ParamIRTypes.size(),
-        conv == ParameterConvention::Indirect_InoutAliasable);
-    addPointerParameter(IGM.getStorageType(getSILFuncConventions().getSILType(
-        param, IGM.getMaximalTypeExpansionContext())));
+      IGM, paramSILType, Attrs, ti, ParamIRTypes.size(),
+      conv == ParameterConvention::Indirect_InoutAliasable,
+      isAddressableParam(paramIdx));
+    addOpaquePointerParameter();
     return ti;
 
   case ParameterConvention::Pack_Guaranteed:
   case ParameterConvention::Pack_Owned:
   case ParameterConvention::Pack_Inout:
     addPackParameterAttributes(IGM, paramSILType, Attrs, ParamIRTypes.size());
-    addPointerParameter(ti.getStorageType());
+    addOpaquePointerParameter();
     return ti;
 
   case ParameterConvention::Direct_Owned:
@@ -1822,8 +1851,9 @@ const TypeInfo &SignatureExpansion::expand(SILParameterInfo param) {
       auto &nativeSchema = ti.nativeParameterValueSchema(IGM);
       if (nativeSchema.requiresIndirect()) {
         addIndirectValueParameterAttributes(IGM, Attrs, ti,
-                                            ParamIRTypes.size());
-        ParamIRTypes.push_back(ti.getStorageType()->getPointerTo());
+                                            ParamIRTypes.size(),
+                                            /*addressable*/ false);
+        addOpaquePointerParameter();
         return ti;
       }
       if (nativeSchema.empty()) {
@@ -1842,6 +1872,13 @@ const TypeInfo &SignatureExpansion::expand(SILParameterInfo param) {
   llvm_unreachable("bad parameter convention");
 }
 
+bool SignatureExpansion::isAddressableParam(unsigned paramIdx) {
+  return FnType->isAddressable(paramIdx, IGM.IRGen.SIL,
+                               IGM.getGenericEnvironment(),
+                               IGM.getSILTypes(),
+                               IGM.getMaximalTypeExpansionContext());
+}
+
 /// Does the given function type have a self parameter that should be
 /// given the special treatment for self parameters?
 ///
@@ -1887,7 +1924,6 @@ static void addParamInfo(SignatureExpansionABIDetails *details,
 }
 
 void SignatureExpansion::expandKeyPathAccessorParameters() {
-  auto params = FnType->getParameters();
   unsigned numArgsToExpand;
   SmallVector<llvm::Type *, 4> tailParams;
 
@@ -1933,7 +1969,7 @@ void SignatureExpansion::expandKeyPathAccessorParameters() {
     llvm_unreachable("non keypath accessor convention");
   }
   for (unsigned i = 0; i < numArgsToExpand; i++) {
-    expand(params[i]);
+    expand(i);
   }
   for (auto tailParam : tailParams) {
     ParamIRTypes.push_back(tailParam);
@@ -1972,8 +2008,8 @@ void SignatureExpansion::expandParameters(
     auto fnConv = getSILFuncConventions();
     for (auto indirectResultType : fnConv.getIndirectSILResultTypes(
            IGM.getMaximalTypeExpansionContext())) {
-      auto storageTy = IGM.getStorageType(indirectResultType);
-      addPointerParameter(storageTy);
+      (void)indirectResultType;
+      addOpaquePointerParameter();
     }
     break;
   }
@@ -1987,9 +2023,9 @@ void SignatureExpansion::expandParameters(
     params = params.drop_back();
   }
 
-  for (auto param : params) {
-    const TypeInfo &ti = expand(param);
-    addParamInfo(recordedABIDetails, ti, param.getConvention());
+  for (auto pair : enumerate(params)) {
+    const TypeInfo &ti = expand(pair.index());
+    addParamInfo(recordedABIDetails, ti, pair.value().getConvention());
   }
   if (recordedABIDetails && FnType->hasSelfParam() && !hasSelfContext)
     recordedABIDetails->parameters.back().isSelf = true;
@@ -2015,7 +2051,7 @@ void SignatureExpansion::expandParameters(
 
     if (claimSelf())
       IGM.addSwiftSelfAttributes(Attrs, curLength);
-    expand(FnType->getSelfParameter());
+    expand(FnType->getSelfParameterIndex());
     if (recordedABIDetails)
       recordedABIDetails->hasTrailingSelfParam = true;
     assert(ParamIRTypes.size() == curLength + 1 &&
@@ -2062,8 +2098,7 @@ void SignatureExpansion::expandParameters(
   if (FnType->hasErrorResult()) {
     if (claimError())
       IGM.addSwiftErrorAttributes(Attrs, ParamIRTypes.size());
-    llvm::Type *errorType = getErrorRegisterType();
-    ParamIRTypes.push_back(errorType->getPointerTo());
+    addOpaquePointerParameter();
     if (recordedABIDetails)
       recordedABIDetails->hasErrorResult = true;
     if (getSILFuncConventions().isTypedError()) {
@@ -2081,7 +2116,7 @@ void SignatureExpansion::expandParameters(
           getSILFuncConventions().hasIndirectSILErrorResults() ||
           native.requiresIndirect() ||
           nativeError.shouldReturnTypedErrorIndirectly()) {
-        ParamIRTypes.push_back(IGM.getStorageType(errorType)->getPointerTo());
+        addOpaquePointerParameter();
       }
     }
   }
@@ -2224,8 +2259,7 @@ void SignatureExpansion::addIndirectThrowingResult() {
         getSILFuncConventions().hasIndirectSILErrorResults() ||
         native.requiresIndirect() ||
         nativeError.shouldReturnTypedErrorIndirectly()) {
-      auto errorStorageTy = errorTI.getStorageType();
-      ParamIRTypes.push_back(errorStorageTy->getPointerTo());
+      addOpaquePointerParameter();
     }
   }
 
@@ -2260,8 +2294,8 @@ void SignatureExpansion::expandAsyncEntryType() {
     params = params.drop_back();
   }
 
-  for (auto param : params) {
-    expand(param);
+  for (unsigned i : range(params.size())) {
+    expand(i);
   }
 
   // Next, the generic signature.
@@ -2279,7 +2313,7 @@ void SignatureExpansion::expandAsyncEntryType() {
   if (hasSelfContext) {
     auto curLength = ParamIRTypes.size();
     (void)curLength;
-    expand(FnType->getSelfParameter());
+    expand(FnType->getSelfParameterIndex());
     assert(ParamIRTypes.size() == curLength + 1 &&
            "adding 'self' added unexpected number of parameters");
     if (claimSelf())
@@ -2535,9 +2569,8 @@ llvm::Value *emitIndirectAsyncFunctionPointer(IRGenFunction &IGF,
   llvm::Constant *One =
       llvm::Constant::getIntegerValue(IntPtrTy, APInt(IntPtrTy->getBitWidth(),
                                                       1));
-  llvm::Constant *NegativeOne =
-      llvm::Constant::getIntegerValue(IntPtrTy, APInt(IntPtrTy->getBitWidth(),
-                                                      -2));
+  llvm::Constant *NegativeOne = llvm::Constant::getIntegerValue(
+      IntPtrTy, APInt(IntPtrTy->getBitWidth(), -2, /*isSigned*/ true));
   swift::irgen::Alignment PointerAlignment = IGF.IGM.getPointerAlignment();
 
   llvm::Value *PtrToInt = IGF.Builder.CreatePtrToInt(pointer, IntPtrTy);
@@ -2549,8 +2582,7 @@ llvm::Value *emitIndirectAsyncFunctionPointer(IRGenFunction &IGF,
 
   llvm::Value *UntaggedPointer = IGF.Builder.CreateAnd(PtrToInt, NegativeOne);
   llvm::Value *IntToPtr =
-      IGF.Builder.CreateIntToPtr(UntaggedPointer,
-                                 AsyncFunctionPointerPtrTy->getPointerTo());
+      IGF.Builder.CreateIntToPtr(UntaggedPointer, IGF.IGM.PtrTy);
   llvm::Value *Load = IGF.Builder.CreateLoad(
       IntToPtr, AsyncFunctionPointerPtrTy, PointerAlignment);
 
@@ -2568,7 +2600,7 @@ llvm::Value *emitIndirectCoroFunctionPointer(IRGenFunction &IGF,
   llvm::Constant *One = llvm::Constant::getIntegerValue(
       IntPtrTy, APInt(IntPtrTy->getBitWidth(), 1));
   llvm::Constant *NegativeOne = llvm::Constant::getIntegerValue(
-      IntPtrTy, APInt(IntPtrTy->getBitWidth(), -2));
+      IntPtrTy, APInt(IntPtrTy->getBitWidth(), -2, /*isSigned*/ true));
   swift::irgen::Alignment PointerAlignment = IGF.IGM.getPointerAlignment();
 
   llvm::Value *PtrToInt = IGF.Builder.CreatePtrToInt(pointer, IntPtrTy);
@@ -2579,8 +2611,8 @@ llvm::Value *emitIndirectCoroFunctionPointer(IRGenFunction &IGF,
       IGF.Builder.CreateBitCast(pointer, CoroFunctionPointerPtrTy);
 
   llvm::Value *UntaggedPointer = IGF.Builder.CreateAnd(PtrToInt, NegativeOne);
-  llvm::Value *IntToPtr = IGF.Builder.CreateIntToPtr(
-      UntaggedPointer, CoroFunctionPointerPtrTy->getPointerTo());
+  llvm::Value *IntToPtr =
+      IGF.Builder.CreateIntToPtr(UntaggedPointer, IGF.IGM.PtrTy);
   llvm::Value *Load = IGF.Builder.CreateLoad(IntToPtr, CoroFunctionPointerPtrTy,
                                              PointerAlignment);
 
@@ -2837,7 +2869,9 @@ class SyncCallEmission final : public CallEmission {
         }
       }
       Args[--LastArgWritten] = errorResultSlot.getAddress();
-      addParamAttribute(LastArgWritten, llvm::Attribute::NoCapture);
+      addParamAttribute(LastArgWritten, llvm::Attribute::getWithCaptureInfo(
+                                            IGF.IGM.getLLVMContext(),
+                                            llvm::CaptureInfo::none()));
       IGF.IGM.addSwiftErrorAttributes(CurCallee.getMutableAttributes(),
                                       LastArgWritten);
 
@@ -3219,9 +3253,8 @@ class AsyncCallEmission final : public CallEmission {
                                  getCallee().getFunctionPointer().getKind());
 
     return FunctionPointer::createForAsyncCall(
-        IGF.Builder.CreateBitCast(calleeFunction,
-                                  awaitEntrySig.getType()->getPointerTo()),
-        codeAuthInfo, awaitSig, awaitEntrySig.getType());
+        IGF.Builder.CreateBitCast(calleeFunction, IGF.IGM.PtrTy), codeAuthInfo,
+        awaitSig, awaitEntrySig.getType());
   }
 
   SILType getParameterType(unsigned index) override {
@@ -3896,8 +3929,9 @@ void CallEmission::emitYieldsToExplosion(Explosion &out) {
 
     // If the schema says it's indirect, then we expect a pointer.
     if (schema.isIndirect()) {
-      auto pointer = IGF.Builder.CreateBitCast(rawYieldComponents.claimNext(),
-                                               schema.getIndirectPointerType());
+      auto pointer =
+          IGF.Builder.CreateBitCast(rawYieldComponents.claimNext(),
+                                    schema.getIndirectPointerType(IGF.IGM));
 
       // If it's formally indirect, then we should just add that pointer
       // to the output.
@@ -3924,6 +3958,11 @@ void CallEmission::emitYieldsToExplosion(Explosion &out) {
   }
 }
 
+void CallEmission::emitGuaranteedAddressToExplosion(Explosion &out) {
+  auto call = emitCallSite();
+  out.add(call);
+}
+
 /// Emit the result of this call to an explosion.
 void CallEmission::emitToExplosion(Explosion &out, bool isOutlined) {
   assert(state == State::Emitting);
@@ -3939,6 +3978,14 @@ void CallEmission::emitToExplosion(Explosion &out, bool isOutlined) {
 
   SILFunctionConventions fnConv(getCallee().getSubstFunctionType(),
                                 IGF.getSILModule());
+
+  if (fnConv.hasGuaranteedAddressResult()) {
+    assert(LastArgWritten == 0 &&
+           "@guaranteed_addr along with indirect result?");
+    emitGuaranteedAddressToExplosion(out);
+    return;
+  }
+
   SILType substResultType =
       fnConv.getSILResultType(IGF.IGM.getMaximalTypeExpansionContext());
 
@@ -4538,22 +4585,6 @@ void CallEmission::externalizeArguments(IRGenFunction &IGF, const Callee &callee
 
     bool isForwardableArgument = IGF.isForwardableArgument(i - firstParam);
 
-    // In Swift, values that are foreign references types will always be
-    // pointers. Additionally, we only import functions which use foreign
-    // reference types indirectly (as pointers), so we know in every case, if
-    // the argument type is a foreign reference type, the types will match up
-    // and we can simply use the input directly.
-    if (paramType.isForeignReferenceType()) {
-      auto *arg = in.claimNext();
-      if (isIndirectFormalParameter(params[i - firstParam].getConvention())) {
-        auto storageTy = IGF.IGM.getTypeInfo(paramType).getStorageType();
-        arg = IGF.Builder.CreateLoad(arg, storageTy,
-                                     IGF.IGM.getPointerAlignment());
-      }
-      out.add(arg);
-      continue;
-    }
-
     bool passIndirectToDirect = paramInfo.isIndirectInGuaranteed() && paramType.isSensitive();
     if (passIndirectToDirect) {
       llvm::Value *ptr = in.claimNext();
@@ -4989,7 +5020,9 @@ static void emitRetconCoroutineEntry(
     ArrayRef<llvm::Value *> extraArguments, llvm::Constant *allocFn,
     llvm::Constant *deallocFn, ArrayRef<llvm::Value *> finalArguments) {
   auto prototype =
-      IGF.IGM.getOpaquePtr(IGF.IGM.getAddrOfContinuationPrototype(fnType));
+    IGF.IGM.getOpaquePtr(
+      IGF.IGM.getAddrOfContinuationPrototype(fnType,
+                                             fnType->getInvocationGenericSignature()));
   // Call the right 'llvm.coro.id.retcon' variant.
   SmallVector<llvm::Value *, 8> arguments;
   arguments.push_back(
@@ -5006,6 +5039,11 @@ static void emitRetconCoroutineEntry(
   for (auto *arg : finalArguments) {
     arguments.push_back(arg);
   }
+  std::optional<ArtificialLocation> Loc;
+  if (IGF.getDebugScope()) {
+    Loc.emplace(IGF.getDebugScope(), IGF.IGM.DebugInfo.get(),
+                           IGF.Builder);
+  }
   llvm::Value *id = IGF.Builder.CreateIntrinsicCall(idIntrinsic, arguments);
 
   // Call 'llvm.coro.begin', just for consistency with the normal pattern.
@@ -5095,7 +5133,7 @@ void irgen::emitAsyncFunctionEntry(IRGenFunction &IGF,
 void irgen::emitYieldOnceCoroutineEntry(
     IRGenFunction &IGF, CanSILFunctionType fnType,
     NativeCCEntryPointArgumentEmission &emission) {
-  // Use malloc and free as our allocator.
+  // Use free as our deallocator.
   auto deallocFn = IGF.IGM.getOpaquePtr(IGF.IGM.getFreeFn());
   auto *buffer = emission.getCoroutineBuffer();
   llvm::SmallVector<llvm::Value *, 2> finalArgs;
@@ -5103,15 +5141,19 @@ void irgen::emitYieldOnceCoroutineEntry(
   if (IGF.getOptions().EmitTypeMallocForCoroFrame) {
     auto mallocTypeId = IGF.getMallocTypeId();
     finalArgs.push_back(mallocTypeId);
-    allocFn = IGF.IGM.getOpaquePtr(IGF.IGM.getCoroFrameAllocFn());
+    // Use swift_coroFrameAllocStub to emit our allocator.
+    allocFn = IGF.IGM.getOpaquePtr(getCoroFrameAllocStubFn(IGF.IGM));
   } else {
+    // Use malloc as our allocator.
     allocFn = IGF.IGM.getOpaquePtr(IGF.IGM.getMallocFn());
   }
+
   emitRetconCoroutineEntry(IGF, fnType, buffer,
                            llvm::Intrinsic::coro_id_retcon_once,
                            getYieldOnceCoroutineBufferSize(IGF.IGM),
                            getYieldOnceCoroutineBufferAlignment(IGF.IGM), {},
                            allocFn, deallocFn, finalArgs);
+
 }
 
 void irgen::emitYieldManyCoroutineEntry(
@@ -5164,8 +5206,7 @@ static llvm::Constant *getCoroAllocFn(IRGenModule &IGM) {
             {llvm::ConstantInt::get(IGF.IGM.Int32Ty, 0),
              llvm::ConstantInt::get(IGF.IGM.Int32Ty, 1)});
         auto *callee = IGF.Builder.CreateLoad(
-            Address(calleePtr, IGF.IGM.CoroAllocateFnTy->getPointerTo(),
-                    IGF.IGM.getPointerAlignment()),
+            Address(calleePtr, IGF.IGM.PtrTy, IGF.IGM.getPointerAlignment()),
             "allocate_fn");
         auto fnPtr = FunctionPointer::createUnsigned(
             FunctionPointer::Kind::Function, callee,
@@ -5242,8 +5283,7 @@ static llvm::Constant *getCoroDeallocFn(IRGenModule &IGM) {
             {llvm::ConstantInt::get(IGF.IGM.Int32Ty, 0),
              llvm::ConstantInt::get(IGF.IGM.Int32Ty, 2)});
         auto *callee = IGF.Builder.CreateLoad(
-            Address(calleePtr, IGF.IGM.CoroDeallocateFnTy->getPointerTo(),
-                    IGF.IGM.getPointerAlignment()),
+            Address(calleePtr, IGF.IGM.PtrTy, IGF.IGM.getPointerAlignment()),
             "deallocate_fn");
         auto fnPtr = FunctionPointer::createUnsigned(
             FunctionPointer::Kind::Function, callee,
@@ -5553,14 +5593,20 @@ void CallEmission::setArgs(Explosion &adjusted, bool isOutlined,
   }
 }
 
-void CallEmission::addFnAttribute(llvm::Attribute::AttrKind attr) {
+void CallEmission::addFnAttribute(llvm::Attribute::AttrKind kind) {
   assert(state == State::Emitting);
   auto &attrs = CurCallee.getMutableAttributes();
-  attrs = attrs.addFnAttribute(IGF.IGM.getLLVMContext(), attr);
+  attrs = attrs.addFnAttribute(IGF.IGM.getLLVMContext(), kind);
+}
+
+void CallEmission::addParamAttribute(unsigned paramIndex,
+                                     llvm::Attribute::AttrKind kind) {
+  addParamAttribute(paramIndex,
+                    llvm::Attribute::get(IGF.IGM.getLLVMContext(), kind));
 }
 
 void CallEmission::addParamAttribute(unsigned paramIndex,
-                                     llvm::Attribute::AttrKind attr) {
+                                     llvm::Attribute attr) {
   assert(state == State::Emitting);
   auto &attrs = CurCallee.getMutableAttributes();
   attrs = attrs.addParamAttribute(IGF.IGM.getLLVMContext(), paramIndex, attr);
@@ -6386,8 +6432,7 @@ Explosion IRGenFunction::coerceValueTo(SILType fromTy, Explosion &from,
   auto temporary = toTI.allocateStack(*this, toTy, "coerce.temp");
 
   auto addr =
-      Address(Builder.CreateBitCast(temporary.getAddressPointer(),
-                                    fromTI.getStorageType()->getPointerTo()),
+      Address(Builder.CreateBitCast(temporary.getAddressPointer(), IGM.PtrTy),
               fromTI.getStorageType(), temporary.getAlignment());
   fromTI.initialize(*this, from, addr, false);
 
@@ -6523,7 +6568,7 @@ Signature irgen::emitCastOfFunctionPointer(IRGenFunction &IGF,
                             : IGF.IGM.getSignature(fnType);
 
   // Emit the cast.
-  fnPtr = IGF.Builder.CreateBitCast(fnPtr, sig.getType()->getPointerTo());
+  fnPtr = IGF.Builder.CreateBitCast(fnPtr, IGF.IGM.PtrTy);
 
   // Return the information.
   return sig;
@@ -7000,6 +7045,16 @@ void irgen::emitYieldOnceCoroutineResult(IRGenFunction &IGF, Explosion &result,
   }
 }
 
+void irgen::emitGuaranteedAddressResult(IRGenFunction &IGF, Explosion &result,
+                                        SILType funcResultType,
+                                        SILType returnResultType) {
+  assert(funcResultType == returnResultType);
+  assert(funcResultType.isAddress());
+  auto &Builder = IGF.Builder;
+  Builder.CreateRet(result.claimNext());
+  assert(result.empty());
+}
+
 FunctionPointer
 IRGenFunction::getFunctionPointerForResumeIntrinsic(llvm::Value *resume) {
   auto *fnTy = llvm::FunctionType::get(
@@ -7012,7 +7067,7 @@ IRGenFunction::getFunctionPointerForResumeIntrinsic(llvm::Value *resume) {
       Signature(fnTy, attrs, IGM.SwiftAsyncCC);
   auto fnPtr = FunctionPointer::createUnsigned(
       FunctionPointer::Kind::Function,
-      Builder.CreateBitOrPointerCast(resume, fnTy->getPointerTo()), signature);
+      Builder.CreateBitOrPointerCast(resume, IGM.PtrTy), signature);
   return fnPtr;
 }
 
diff --git a/lib/IRGen/GenCall.h b/lib/IRGen/GenCall.h
index 66194a70bd070..ec2cd8a5c1b40 100644
--- a/lib/IRGen/GenCall.h
+++ b/lib/IRGen/GenCall.h
@@ -281,6 +281,10 @@ namespace irgen {
   void emitYieldOnceCoroutineResult(IRGenFunction &IGF, Explosion &result,
                                     SILType funcResultType, SILType returnResultType);
 
+  void emitGuaranteedAddressResult(IRGenFunction &IGF, Explosion &result,
+                                   SILType funcResultType,
+                                   SILType returnResultType);
+
   Address emitAutoDiffCreateLinearMapContextWithType(
       IRGenFunction &IGF, llvm::Value *topLevelSubcontextMetatype);
 
diff --git a/lib/IRGen/GenCast.cpp b/lib/IRGen/GenCast.cpp
index b15002ea7a1ad..2f6eb20f57621 100644
--- a/lib/IRGen/GenCast.cpp
+++ b/lib/IRGen/GenCast.cpp
@@ -45,7 +45,7 @@ using namespace irgen;
 static DynamicCastFlags getDynamicCastFlags(
     CastConsumptionKind consumptionKind,
     CheckedCastMode mode,
-    CastingIsolatedConformances isolatedConformances
+    CheckedCastInstOptions options
 ) {
   DynamicCastFlags flags = DynamicCastFlags::Default;
 
@@ -56,7 +56,7 @@ static DynamicCastFlags getDynamicCastFlags(
   if (shouldTakeOnSuccess(consumptionKind))
     flags |= DynamicCastFlags::TakeOnSuccess;
 
-  switch (isolatedConformances) {
+  switch (options.isolatedConformances()) {
   case CastingIsolatedConformances::Allow:
     break;
   case CastingIsolatedConformances::Prohibit:
@@ -75,11 +75,10 @@ llvm::Value *irgen::emitCheckedCast(IRGenFunction &IGF,
                                     CanType targetType,
                                     CastConsumptionKind consumptionKind,
                                     CheckedCastMode mode,
-                            CastingIsolatedConformances isolatedConformances) {
+                                    CheckedCastInstOptions options) {
   // TODO: attempt to specialize this based on the known types.
 
-  DynamicCastFlags flags = getDynamicCastFlags(consumptionKind, mode,
-                                               isolatedConformances);
+  DynamicCastFlags flags = getDynamicCastFlags(consumptionKind, mode, options);
 
   // Cast both addresses to opaque pointer type.
   dest = IGF.Builder.CreateElementBitCast(dest, IGF.IGM.OpaqueTy);
@@ -211,7 +210,8 @@ llvm::Value *irgen::emitClassDowncast(IRGenFunction &IGF, llvm::Value *from,
 
   // If the destination type is known to have a Swift-compatible
   // implementation, use the most specific entrypoint.
-  if (destClass && destClass->hasKnownSwiftImplementation()) {
+  if ((destClass && destClass->hasKnownSwiftImplementation()) ||
+      IGF.IGM.Context.LangOpts.hasFeature(Feature::Embedded)) {
     metadataRef = IGF.emitTypeMetadataRef(toType);
 
     switch (mode) {
@@ -545,8 +545,8 @@ llvm::Value *irgen::emitMetatypeToAnyObjectDowncast(IRGenFunction &IGF,
 /// Emit a checked cast to a protocol or protocol composition.
 void irgen::emitScalarExistentialDowncast(
     IRGenFunction &IGF, llvm::Value *value, SILType srcType, SILType destType,
-    CheckedCastMode mode, std::optional<MetatypeRepresentation> metatypeKind,
-    Explosion &ex) {
+    CheckedCastMode mode, bool sourceWrappedInOptional,
+    std::optional<MetatypeRepresentation> metatypeKind, Explosion &ex) {
   auto srcInstanceType = srcType.getASTType();
   auto destInstanceType = destType.getASTType();
   while (auto metatypeType = dyn_cast<ExistentialMetatypeType>(
@@ -801,7 +801,36 @@ void irgen::emitScalarExistentialDowncast(
   for (auto proto : witnessTableProtos)
     args.push_back(proto);
 
-  auto valueAndWitnessTables = IGF.Builder.CreateCall(fn, args);
+  llvm::BasicBlock *nilCheckedCont = nullptr;
+  llvm::BasicBlock *nilBB = nullptr;
+  llvm::BasicBlock *nonNilBB = nullptr;
+  if (sourceWrappedInOptional) {
+    nilBB = IGF.createBasicBlock("is-nil");
+    nonNilBB = IGF.createBasicBlock("is-non-nil");
+    nilCheckedCont = IGF.createBasicBlock("nil-checked-cont");
+
+    auto isNotNil = IGF.Builder.CreateICmpNE(
+        metadataValue, llvm::ConstantPointerNull::get(
+                           cast<llvm::PointerType>(IGF.IGM.Int8PtrTy)));
+
+    IGF.Builder.CreateCondBr(isNotNil, nonNilBB, nilBB);
+    IGF.Builder.emitBlock(nilBB);
+    IGF.Builder.CreateBr(nilCheckedCont);
+    IGF.Builder.emitBlock(nonNilBB);
+  }
+
+  llvm::Value *valueAndWitnessTables = IGF.Builder.CreateCall(fn, args);
+
+  if (nilCheckedCont) {
+    IGF.Builder.CreateBr(nilCheckedCont);
+    IGF.Builder.emitBlock(nilCheckedCont);
+    auto *returnTy = valueAndWitnessTables->getType();
+    auto failureVal = llvm::Constant::getNullValue(returnTy);
+    auto phi = IGF.Builder.CreatePHI(returnTy, 2);
+    phi->addIncoming(valueAndWitnessTables, nonNilBB);
+    phi->addIncoming(failureVal, nilBB);
+    valueAndWitnessTables = phi;
+  }
 
   resultValue = IGF.Builder.CreateExtractValue(valueAndWitnessTables, 0);
   if (resultValue->getType() != resultType)
@@ -860,7 +889,7 @@ void irgen::emitScalarCheckedCast(IRGenFunction &IGF,
                                   SILType targetLoweredType,
                                   CanType targetFormalType,
                                   CheckedCastMode mode,
-                              CastingIsolatedConformances isolatedConformances,
+                                  CheckedCastInstOptions options,
                                   Explosion &out) {
   assert(sourceLoweredType.isObject());
   assert(targetLoweredType.isObject());
@@ -946,10 +975,9 @@ void irgen::emitScalarCheckedCast(IRGenFunction &IGF,
 
     // Casts to existential metatypes.
     if (auto existential = targetLoweredType.getAs<ExistentialMetatypeType>()) {
-      emitScalarExistentialDowncast(IGF, metatypeVal, sourceLoweredType,
-                                    targetLoweredType, mode,
-                                    existential->getRepresentation(),
-                                    out);
+      emitScalarExistentialDowncast(
+          IGF, metatypeVal, sourceLoweredType, targetLoweredType, mode,
+          sourceWrappedInOptional, existential->getRepresentation(), out);
       return;
 
     // Casts to concrete metatypes.
@@ -981,7 +1009,7 @@ void irgen::emitScalarCheckedCast(IRGenFunction &IGF,
                                        IGF.IGM.getPointerAlignment(),
                                        "castSrc");
         IGF.Builder.CreateStore(metatypeVal, src);
-        llvm::PointerType *destPtrType = IGF.IGM.getStoragePointerType(targetLoweredType);
+        llvm::PointerType *destPtrType = IGF.IGM.PtrTy;
         Address dest = IGF.createAlloca(destPtrType,
                                         IGF.IGM.getPointerAlignment(),
                                         "castDest");
@@ -990,7 +1018,7 @@ void irgen::emitScalarCheckedCast(IRGenFunction &IGF,
                                                src, sourceFormalType,
                                                dest, targetFormalType,
                                                CastConsumptionKind::TakeAlways,
-                                               mode, isolatedConformances);
+                                               mode, options);
         llvm::Value *successResult = IGF.Builder.CreateLoad(dest);
         llvm::Value *failureResult = llvm::ConstantPointerNull::get(destPtrType);
         llvm::Value *result = IGF.Builder.CreateSelect(success, successResult, failureResult);
@@ -1024,15 +1052,16 @@ void irgen::emitScalarCheckedCast(IRGenFunction &IGF,
 
   if (targetFormalType.isExistentialType()) {
     Explosion outRes;
-    emitScalarExistentialDowncast(
-        IGF, instance, sourceLoweredType, targetLoweredType, mode,
-        /*not a metatype*/ std::nullopt, outRes);
+    emitScalarExistentialDowncast(IGF, instance, sourceLoweredType,
+                                  targetLoweredType, mode,
+                                  /*sourceWrappedInOptional*/ false,
+                                  /*not a metatype*/ std::nullopt, outRes);
     returnNilCheckedResult(IGF.Builder, outRes);
     return;
   }
 
   if (llvm::Value *fastResult = emitFastClassCastIfPossible(
-          IGF, instance, sourceFormalType, targetFormalType,
+          IGF, instance, sourceFormalType, targetFormalType, mode,
           sourceWrappedInOptional, nilCheckBB, nilMergeBB)) {
     Explosion fastExplosion;
     fastExplosion.add(fastResult);
@@ -1054,7 +1083,7 @@ void irgen::emitScalarCheckedCast(IRGenFunction &IGF,
 /// not required that the metadata is fully initialized.
 llvm::Value *irgen::emitFastClassCastIfPossible(
     IRGenFunction &IGF, llvm::Value *instance, CanType sourceFormalType,
-    CanType targetFormalType, bool sourceWrappedInOptional,
+    CanType targetFormalType, CheckedCastMode mode, bool sourceWrappedInOptional,
     llvm::BasicBlock *&nilCheckBB, llvm::BasicBlock *&nilMergeBB) {
   if (!doesCastPreserveOwnershipForTypes(IGF.IGM.getSILModule(),
                                          sourceFormalType, targetFormalType)) {
@@ -1089,15 +1118,18 @@ llvm::Value *irgen::emitFastClassCastIfPossible(
 
   // If the source was originally wrapped in an Optional, check it for nil now.
   if (sourceWrappedInOptional) {
-    auto isNotNil = IGF.Builder.CreateICmpNE(
+    auto isNil = IGF.Builder.CreateICmpEQ(
         instance, llvm::ConstantPointerNull::get(
                       cast<llvm::PointerType>(instance->getType())));
-    auto *isNotNilContBB = llvm::BasicBlock::Create(IGF.IGM.getLLVMContext());
-    nilMergeBB = llvm::BasicBlock::Create(IGF.IGM.getLLVMContext());
-    nilCheckBB = IGF.Builder.GetInsertBlock();
-    IGF.Builder.CreateCondBr(isNotNil, isNotNilContBB, nilMergeBB);
-
-    IGF.Builder.emitBlock(isNotNilContBB);
+    if (mode == CheckedCastMode::Unconditional) {
+      IGF.emitConditionalTrap(isNil, "Unexpectedly found nil while unwrapping an Optional value");
+    } else {
+      auto *isNotNilContBB = llvm::BasicBlock::Create(IGF.IGM.getLLVMContext());
+      nilMergeBB = llvm::BasicBlock::Create(IGF.IGM.getLLVMContext());
+      nilCheckBB = IGF.Builder.GetInsertBlock();
+      IGF.Builder.CreateCondBr(isNil, nilMergeBB, isNotNilContBB);
+      IGF.Builder.emitBlock(isNotNilContBB);
+    }
   }
 
   // Get the metadata pointer of the destination class type.
@@ -1121,11 +1153,15 @@ llvm::Value *irgen::emitFastClassCastIfPossible(
   llvm::Value *rhs = IGF.Builder.CreateBitCast(objMetadata, IGF.IGM.Int8PtrTy);
   
   // return isa_ptr == metadata_ptr ? instance : nullptr
-  llvm::Value *isEqual = IGF.Builder.CreateCmp(llvm::CmpInst::Predicate::ICMP_EQ,
+  llvm::Value *isNotEqual = IGF.Builder.CreateCmp(llvm::CmpInst::Predicate::ICMP_NE,
                                               lhs, rhs);
+  if (mode == CheckedCastMode::Unconditional) {
+    IGF.emitConditionalTrap(isNotEqual, "Unconditional cast failed");
+    return instance;
+  }
   auto *instanceTy = cast<llvm::PointerType>(instance->getType());
   auto *nullPtr = llvm::ConstantPointerNull::get(instanceTy);
-  auto *select = IGF.Builder.CreateSelect(isEqual, instance, nullPtr);
+  auto *select = IGF.Builder.CreateSelect(isNotEqual, nullPtr, instance);
   llvm::Type *destTy = IGF.getTypeInfoForUnlowered(targetFormalType).getStorageType();
   return IGF.Builder.CreateBitCast(select, destTy);
 }
diff --git a/lib/IRGen/GenCast.h b/lib/IRGen/GenCast.h
index 3529b466709a4..381a7e091f10e 100644
--- a/lib/IRGen/GenCast.h
+++ b/lib/IRGen/GenCast.h
@@ -28,7 +28,7 @@ namespace swift {
   class SILType;
   class ProtocolDecl;
   enum class CastConsumptionKind : unsigned char;
-  enum class CastingIsolatedConformances: uint8_t;
+  class CheckedCastInstOptions;
 
 namespace irgen {
   class Address;
@@ -48,7 +48,7 @@ namespace irgen {
                                CanType toType,
                                CastConsumptionKind consumptionKind,
                                CheckedCastMode mode,
-                              CastingIsolatedConformances isolatedConformances);
+                               CheckedCastInstOptions options);
 
   void emitScalarCheckedCast(IRGenFunction &IGF, Explosion &value,
                              SILType sourceLoweredType,
@@ -56,12 +56,12 @@ namespace irgen {
                              SILType targetLoweredType,
                              CanType targetFormalType,
                              CheckedCastMode mode,
-                             CastingIsolatedConformances isolatedConformances,
+                             CheckedCastInstOptions options,
                              Explosion &out);
 
   llvm::Value *emitFastClassCastIfPossible(
       IRGenFunction &IGF, llvm::Value *instance, CanType sourceFormalType,
-      CanType targetFormalType, bool sourceWrappedInOptional,
+      CanType targetFormalType, CheckedCastMode mode, bool sourceWrappedInOptional,
       llvm::BasicBlock *&nilCheckBB, llvm::BasicBlock *&nilMergeBB);
 
   /// Convert a class object to the given destination type,
@@ -99,8 +99,8 @@ namespace irgen {
   /// not, the cast is done as a class instance cast.
   void emitScalarExistentialDowncast(
       IRGenFunction &IGF, llvm::Value *orig, SILType srcType, SILType destType,
-      CheckedCastMode mode, std::optional<MetatypeRepresentation> metatypeKind,
-      Explosion &ex);
+      CheckedCastMode mode, bool sourceWrappedInOptional,
+      std::optional<MetatypeRepresentation> metatypeKind, Explosion &ex);
 
   /// Emit a checked cast from a metatype to AnyObject.
   llvm::Value *emitMetatypeToAnyObjectDowncast(IRGenFunction &IGF,
diff --git a/lib/IRGen/GenClangDecl.cpp b/lib/IRGen/GenClangDecl.cpp
index 73e570bdcf761..7d174e93eeb4b 100644
--- a/lib/IRGen/GenClangDecl.cpp
+++ b/lib/IRGen/GenClangDecl.cpp
@@ -70,7 +70,7 @@ class ClangDeclFinder
           // underlying Clang function that was also synthesized.
           BraceStmt *body = defaultArgGenerator->getTypecheckedBody();
           auto returnStmt =
-              cast<ReturnStmt>(body->getSingleActiveElement().get<Stmt *>());
+              cast<ReturnStmt>(cast<Stmt *>(body->getSingleActiveElement()));
           auto callExpr = cast<CallExpr>(returnStmt->getResult());
           auto calledFuncDecl = cast<FuncDecl>(callExpr->getCalledValue());
           auto calledClangFuncDecl =
diff --git a/lib/IRGen/GenClangType.cpp b/lib/IRGen/GenClangType.cpp
index 70a0551a58992..83f891cdf6e8f 100644
--- a/lib/IRGen/GenClangType.cpp
+++ b/lib/IRGen/GenClangType.cpp
@@ -32,10 +32,6 @@ clang::CanQualType IRGenModule::getClangType(CanType type) {
 }
 
 clang::CanQualType IRGenModule::getClangType(SILType type) {
-  if (type.isForeignReferenceType())
-    return getClangType(type.getASTType()
-                            ->wrapInPointer(PTK_UnsafePointer)
-                            ->getCanonicalType());
   return getClangType(type.getASTType());
 }
 
diff --git a/lib/IRGen/GenClass.cpp b/lib/IRGen/GenClass.cpp
index 1b7f1356eac76..b7f59c9f110e9 100644
--- a/lib/IRGen/GenClass.cpp
+++ b/lib/IRGen/GenClass.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -546,12 +546,11 @@ ClassTypeInfo::getClassLayout(IRGenModule &IGM, SILType classType,
 /// as a size_t), and cast to a pointer to the given type.
 llvm::Value *IRGenFunction::emitByteOffsetGEP(llvm::Value *base,
                                               llvm::Value *offset,
-                                              llvm::Type *objectType,
                                               const llvm::Twine &name) {
   assert(offset->getType() == IGM.SizeTy || offset->getType() == IGM.Int32Ty);
   auto addr = Builder.CreateBitCast(base, IGM.Int8PtrTy);
   addr = Builder.CreateInBoundsGEP(IGM.Int8Ty, addr, offset);
-  return Builder.CreateBitCast(addr, objectType->getPointerTo(), name);
+  return Builder.CreateBitCast(addr, IGM.PtrTy, name);
 }
 
 /// Cast the base to i8*, apply the given inbounds offset (in bytes,
@@ -560,7 +559,7 @@ Address IRGenFunction::emitByteOffsetGEP(llvm::Value *base,
                                          llvm::Value *offset,
                                          const TypeInfo &type,
                                          const llvm::Twine &name) {
-  auto addr = emitByteOffsetGEP(base, offset, type.getStorageType(), name);
+  auto addr = emitByteOffsetGEP(base, offset, name);
   return type.getAddressForPointer(addr);
 }
 
@@ -864,7 +863,6 @@ llvm::Value *irgen::emitClassAllocation(IRGenFunction &IGF, SILType selfType,
   auto &classLayout = classTI.getClassLayout(IGF.IGM, selfType,
                                              /*forBackwardDeployment=*/false);
 
-  llvm::Type *destType = classLayout.getType()->getPointerTo();
   llvm::Value *val = nullptr;
   if (llvm::Value *Promoted = stackPromote(IGF, classLayout, StackAllocSize,
                                            TailArrays)) {
@@ -900,7 +898,7 @@ llvm::Value *irgen::emitClassAllocation(IRGenFunction &IGF, SILType selfType,
     val = IGF.emitAllocObjectCall(metadata, size, alignMask, "reference.new");
     StackAllocSize = -1;
   }
-  return IGF.Builder.CreateBitCast(val, destType);
+  return IGF.Builder.CreateBitCast(val, IGF.IGM.PtrTy);
 }
 
 llvm::Value *irgen::emitClassAllocationDynamic(IRGenFunction &IGF, 
@@ -919,6 +917,7 @@ llvm::Value *irgen::emitClassAllocationDynamic(IRGenFunction &IGF,
   auto &classTI = IGF.getTypeInfo(selfType).as<ClassTypeInfo>();
   auto &classLayout = classTI.getClassLayout(IGF.IGM, selfType,
                                           /*forBackwardDeployment=*/false);
+  auto *destType = IGF.IGM.PtrTy;
 
   // If we are allowed to allocate on the stack we are allowed to use
   // `selfType`'s size assumptions.
@@ -929,7 +928,6 @@ llvm::Value *irgen::emitClassAllocationDynamic(IRGenFunction &IGF,
                                                  IGF.IGM.RefCountedPtrTy);
     val = IGF.emitInitStackObjectCall(metadata, val, "reference.new");
 
-    llvm::Type *destType = classLayout.getType()->getPointerTo();
     return IGF.Builder.CreateBitCast(val, destType);
   }
 
@@ -945,7 +943,6 @@ llvm::Value *irgen::emitClassAllocationDynamic(IRGenFunction &IGF,
   llvm::Value *val = IGF.emitAllocObjectCall(metadata, size, alignMask,
                                              "reference.new");
   StackAllocSize = -1;
-  llvm::Type *destType = classLayout.getType()->getPointerTo();
   return IGF.Builder.CreateBitCast(val, destType);
 }
 
@@ -1467,7 +1464,8 @@ namespace {
 
       // struct category_t {
       //   char const *name;
-      fields.add(IGM.getAddrOfGlobalString(CategoryName));
+      fields.add(IGM.getAddrOfGlobalString(CategoryName,
+                                           CStringSectionType::ObjCClassName));
       //   const class_t *theClass;
       fields.add(getClassMetadataRef());
       //   const method_list_t *instanceMethods;
@@ -1506,7 +1504,8 @@ namespace {
       //   Class super;
       fields.addNullPointer(IGM.Int8PtrTy);
       //   char const *name;
-      fields.add(IGM.getAddrOfGlobalString(getEntityName(nameBuffer)));
+      fields.add(IGM.getAddrOfGlobalString(getEntityName(nameBuffer),
+                                           CStringSectionType::ObjCClassName));
       //   const protocol_list_t *baseProtocols;
       fields.add(buildProtocolList(weakLinkage));
       //   const method_list_t *requiredInstanceMethods;
@@ -1727,7 +1726,8 @@ namespace {
       }
       
       llvm::SmallString<64> buffer;
-      Name = IGM.getAddrOfGlobalString(getClass()->getObjCRuntimeName(buffer));
+      Name = IGM.getAddrOfGlobalString(getClass()->getObjCRuntimeName(buffer),
+                                       CStringSectionType::ObjCClassName);
       return Name;
     }
 
@@ -1853,8 +1853,7 @@ namespace {
                                         accessor->getStorage());
 
 #define OBJC_ACCESSOR(ID, KEYWORD)
-#define ACCESSOR(ID) \
-      case AccessorKind::ID:
+#define ACCESSOR(ID, KEYWORD) case AccessorKind::ID:
       case AccessorKind::DistributedGet:
 #include "swift/AST/AccessorKinds.def"
         llvm_unreachable("shouldn't be trying to build this accessor");
@@ -2067,19 +2066,35 @@ namespace {
       }
 
       StringRef name = field.getName();
+      std::string typeEnc;
+      if (field.getKind() == Field::Var) {
+        auto *varDecl = field.getVarDecl();
+        if (varDecl->isObjC() && varDecl->hasStorage()) {
+          auto varTy = varDecl->getInterfaceType();
+          auto varDC = varDecl->getDeclContext();
+          bool isTriviallyRepresentable = varTy->isTriviallyRepresentableIn(
+              ForeignLanguage::ObjectiveC, varDC);
+
+          if (isTriviallyRepresentable)
+            getObjCEncodingForPropertyType(IGM, varDecl, typeEnc);
+          else
+            // "Unknown type" - used when ObjC classes are bridged to separate
+            // Swift types.
+            typeEnc = "?";
+        }
+      }
       const TypeInfo &storageTI = pair.second.getType();
       auto fields = ivars.beginStruct();
 
       if (offsetPtr)
         fields.add(offsetPtr);
       else
-        fields.addNullPointer(IGM.IntPtrTy->getPointerTo());
-
-      // TODO: clang puts this in __TEXT,__objc_methname,cstring_literals
-      fields.add(IGM.getAddrOfGlobalString(name));
+        fields.addNullPointer(IGM.PtrTy);
 
-      // TODO: clang puts this in __TEXT,__objc_methtype,cstring_literals
-      fields.add(IGM.getAddrOfGlobalString(""));
+      fields.add(
+          IGM.getAddrOfGlobalString(name, CStringSectionType::ObjCMethodName));
+      fields.add(IGM.getAddrOfGlobalString(typeEnc,
+                                           CStringSectionType::ObjCMethodType));
 
       Size size;
       Alignment alignment;
@@ -2215,8 +2230,11 @@ namespace {
       buildPropertyAttributes(prop, propertyAttributes);
       
       auto fields = properties.beginStruct();
-      fields.add(IGM.getAddrOfGlobalString(prop->getObjCPropertyName().str()));
-      fields.add(IGM.getAddrOfGlobalString(propertyAttributes));
+      fields.add(
+          IGM.getAddrOfGlobalString(prop->getObjCPropertyName().str(),
+                                    CStringSectionType::ObjCPropertyName));
+      fields.add(IGM.getAddrOfGlobalString(
+          propertyAttributes, CStringSectionType::ObjCPropertyName));
       fields.finishAndAddTo(properties);
     }
 
@@ -2618,8 +2636,7 @@ llvm::Constant *IRGenModule::emitObjCResilientClassStub(
   auto *objcStub = llvm::ConstantExpr::getBitCast(fullObjCStub, Int8PtrTy);
   objcStub = llvm::ConstantExpr::getInBoundsGetElementPtr(
       Int8Ty, objcStub, getSize(getPointerSize()));
-  objcStub = llvm::ConstantExpr::getPointerCast(objcStub,
-      ObjCResilientClassStubTy->getPointerTo());
+  objcStub = llvm::ConstantExpr::getPointerCast(objcStub, PtrTy);
 
   if (isPublic) {
     entity = LinkEntity::forObjCResilientClassStub(
@@ -2784,7 +2801,6 @@ llvm::Constant *irgen::emitObjCProtocolData(IRGenModule &IGM,
 const TypeInfo *
 TypeConverter::convertClassType(CanType type, ClassDecl *D) {
   llvm::StructType *ST = IGM.createNominalType(type);
-  llvm::PointerType *irType = ST->getPointerTo();
   ReferenceCounting refcount = type->getReferenceCounting();
   
   SpareBitVector spareBits;
@@ -2797,8 +2813,9 @@ TypeConverter::convertClassType(CanType type, ClassDecl *D) {
   else
     spareBits = IGM.getHeapObjectSpareBits();
 
-  return new ClassTypeInfo(irType, IGM.getPointerSize(), std::move(spareBits),
-                           IGM.getPointerAlignment(), D, refcount, ST);
+  return new ClassTypeInfo(IGM.PtrTy, IGM.getPointerSize(),
+                           std::move(spareBits), IGM.getPointerAlignment(), D,
+                           refcount, ST);
 }
 
 /// Lazily declare a fake-looking class to represent an ObjC runtime base class.
@@ -3065,8 +3082,7 @@ static llvm::Value *emitVTableSlotLoad(IRGenFunction &IGF, Address slot,
     llvm::Value *checkedLoad = IGF.Builder.CreateIntrinsicCall(
         llvm::Intrinsic::type_checked_load, args);
     auto fnPtr = IGF.Builder.CreateExtractValue(checkedLoad, 0);
-    return IGF.Builder.CreateBitCast(fnPtr,
-                                     signature.getType()->getPointerTo());
+    return IGF.Builder.CreateBitCast(fnPtr, IGF.IGM.PtrTy);
   }
 
   // Not doing LLVM IR VFE, can just be a direct load.
@@ -3088,8 +3104,7 @@ FunctionPointer irgen::emitVirtualMethodValue(IRGenFunction &IGF,
   case ClassMetadataLayout::MethodInfo::Kind::Offset: {
     auto offset = methodInfo.getOffset();
 
-    auto slot = IGF.emitAddressAtOffset(metadata, offset,
-                                        signature.getType()->getPointerTo(),
+    auto slot = IGF.emitAddressAtOffset(metadata, offset, IGF.IGM.PtrTy,
                                         IGF.IGM.getPointerAlignment());
     auto fnPtr = emitVTableSlotLoad(IGF, slot, method, signature);
     auto &schema = methodType->isAsync()
@@ -3104,7 +3119,7 @@ FunctionPointer irgen::emitVirtualMethodValue(IRGenFunction &IGF,
   }
   case ClassMetadataLayout::MethodInfo::Kind::DirectImpl: {
     auto fnPtr = llvm::ConstantExpr::getBitCast(methodInfo.getDirectImpl(),
-                                           signature.getType()->getPointerTo());
+                                                IGF.IGM.PtrTy);
     llvm::Constant *secondaryValue = nullptr;
     auto *accessor = dyn_cast<AccessorDecl>(method.getDecl());
     if (cast<AbstractFunctionDecl>(method.getDecl())->hasAsync()) {
diff --git a/lib/IRGen/GenConcurrency.cpp b/lib/IRGen/GenConcurrency.cpp
index 95945c087da3d..10f4aac0d291f 100644
--- a/lib/IRGen/GenConcurrency.cpp
+++ b/lib/IRGen/GenConcurrency.cpp
@@ -249,7 +249,7 @@ llvm::Value *irgen::emitBuiltinStartAsyncLet(IRGenFunction &IGF,
       llvm::ConstantPointerNull::get(IGF.IGM.Int8PtrTy);
   if (!IGF.IGM.Context.LangOpts.hasFeature(Feature::Embedded)) {
     futureResultTypeMetadata =
-        IGF.emitAbstractTypeMetadataRef(futureResultType);
+        IGF.emitTypeMetadataRef(futureResultType);
   }
 
   // The concurrency runtime for older Apple OSes has a bug in task formation
@@ -352,7 +352,7 @@ llvm::Value *irgen::emitCreateTaskGroup(IRGenFunction &IGF,
     return group;
   }
 
-  auto resultTypeMetadata = IGF.emitAbstractTypeMetadataRef(resultType);
+  auto resultTypeMetadata = IGF.emitTypeMetadataRef(resultType);
 
   llvm::CallInst *call;
   if (groupFlags) {
@@ -416,7 +416,7 @@ void irgen::emitTaskRunInline(IRGenFunction &IGF, SubstitutionMap subs,
   assert(subs.getReplacementTypes().size() == 1 &&
          "taskRunInline should have a type substitution");
   auto resultType = subs.getReplacementTypes()[0]->getCanonicalType();
-  auto resultTypeMetadata = IGF.emitAbstractTypeMetadataRef(resultType);
+  auto resultTypeMetadata = IGF.emitTypeMetadataRef(resultType);
 
   auto *call = IGF.Builder.CreateCall(
       IGF.IGM.getTaskRunInlineFunctionPointer(),
diff --git a/lib/IRGen/GenConstant.cpp b/lib/IRGen/GenConstant.cpp
index 6f4a7d7e7be4d..4dc9c9190af56 100644
--- a/lib/IRGen/GenConstant.cpp
+++ b/lib/IRGen/GenConstant.cpp
@@ -66,42 +66,6 @@ llvm::Constant *irgen::emitConstantInt(IRGenModule &IGM,
   return llvm::ConstantInt::get(IGM.getLLVMContext(), value);
 }
 
-llvm::Constant *irgen::emitConstantZero(IRGenModule &IGM, BuiltinInst *BI) {
-  assert(IGM.getSILModule().getBuiltinInfo(BI->getName()).ID ==
-         BuiltinValueKind::ZeroInitializer);
-
-  auto helper = [&](CanType astType) -> llvm::Constant * {
-    if (auto type = astType->getAs<BuiltinIntegerType>()) {
-      APInt zero(type->getWidth().getLeastWidth(), 0);
-      return llvm::ConstantInt::get(IGM.getLLVMContext(), zero);
-    }
-
-    if (auto type = astType->getAs<BuiltinFloatType>()) {
-      const llvm::fltSemantics *sema = nullptr;
-      switch (type->getFPKind()) {
-      case BuiltinFloatType::IEEE16: sema = &APFloat::IEEEhalf(); break;
-      case BuiltinFloatType::IEEE32: sema = &APFloat::IEEEsingle(); break;
-      case BuiltinFloatType::IEEE64: sema = &APFloat::IEEEdouble(); break;
-      case BuiltinFloatType::IEEE80: sema = &APFloat::x87DoubleExtended(); break;
-      case BuiltinFloatType::IEEE128: sema = &APFloat::IEEEquad(); break;
-      case BuiltinFloatType::PPC128: sema = &APFloat::PPCDoubleDouble(); break;
-      }
-      auto zero = APFloat::getZero(*sema);
-      return llvm::ConstantFP::get(IGM.getLLVMContext(), zero);
-    }
-
-    llvm_unreachable("SIL allowed an unknown type?");
-  };
-
-  if (auto vector = BI->getType().getAs<BuiltinVectorType>()) {
-    auto zero = helper(vector.getElementType());
-    auto count = llvm::ElementCount::getFixed(vector->getNumElements());
-    return llvm::ConstantVector::getSplat(count, zero);
-  }
-
-  return helper(BI->getType().getASTType());
-}
-
 llvm::Constant *irgen::emitConstantFP(IRGenModule &IGM, FloatLiteralInst *FLI) {
   return llvm::ConstantFP::get(IGM.getLLVMContext(), FLI->getValue());
 }
@@ -115,7 +79,9 @@ llvm::Constant *irgen::emitAddrOfConstantString(IRGenModule &IGM,
   case StringLiteralInst::Encoding::Bytes:
   case StringLiteralInst::Encoding::UTF8:
   case StringLiteralInst::Encoding::UTF8_OSLOG:
-    return IGM.getAddrOfGlobalString(SLI->getValue(), false, useOSLogEncoding);
+    return IGM.getAddrOfGlobalString(
+        SLI->getValue(), useOSLogEncoding ? CStringSectionType::OSLogString
+                                          : CStringSectionType::Default);
 
   case StringLiteralInst::Encoding::ObjCSelector:
     llvm_unreachable("cannot get the address of an Objective-C selector");
@@ -311,8 +277,15 @@ Explosion irgen::emitConstantValue(IRGenModule &IGM, SILValue operand,
   } else if (auto *BI = dyn_cast<BuiltinInst>(operand)) {
     auto args = BI->getArguments();
     switch (IGM.getSILModule().getBuiltinInfo(BI->getName()).ID) {
-      case BuiltinValueKind::ZeroInitializer:
-        return emitConstantZero(IGM, BI);
+      case BuiltinValueKind::ZeroInitializer: {
+        auto &resultTI = cast<LoadableTypeInfo>(IGM.getTypeInfo(BI->getType()));
+        auto schema = resultTI.getSchema();
+        Explosion out;
+        for (auto &elt : schema) {
+          out.add(llvm::Constant::getNullValue(elt.getScalarType()));
+        }
+        return out;
+      }
       case BuiltinValueKind::PtrToInt: {
         auto *ptr = emitConstantValue(IGM, args[0]).claimNextConstant();
         return llvm::ConstantExpr::getPtrToInt(ptr, IGM.IntPtrTy);
diff --git a/lib/IRGen/GenConstant.h b/lib/IRGen/GenConstant.h
index 3e8f3812447f0..8de4191ebbf4f 100644
--- a/lib/IRGen/GenConstant.h
+++ b/lib/IRGen/GenConstant.h
@@ -27,9 +27,6 @@ namespace irgen {
 /// Construct a ConstantInt from an IntegerLiteralInst.
 llvm::Constant *emitConstantInt(IRGenModule &IGM, IntegerLiteralInst *ILI);
 
-/// Construct a zero from a zero initializer BuiltinInst.
-llvm::Constant *emitConstantZero(IRGenModule &IGM, BuiltinInst *Bi);
-
 /// Construct a ConstantFP from a FloatLiteralInst.
 llvm::Constant *emitConstantFP(IRGenModule &IGM, FloatLiteralInst *FLI);
 
diff --git a/lib/IRGen/GenCoro.cpp b/lib/IRGen/GenCoro.cpp
new file mode 100644
index 0000000000000..f9ab20348e5b4
--- /dev/null
+++ b/lib/IRGen/GenCoro.cpp
@@ -0,0 +1,614 @@
+//===---- GenCoro.cpp - Code generation related to coroutines -------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/ABI/MetadataValues.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/IRGen/Linking.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+
+#include "Explosion.h"
+#include "IRGenFunction.h"
+#include "IRGenModule.h"
+
+using namespace swift;
+using namespace irgen;
+
+// Add a flag which when set to false forces execution of the open-coded version
+// in order to execution test it.
+static llvm::cl::opt<bool> EnableRuntimeTaskDeallocThrough(
+    "enable-runtime-task-dealloc-through", llvm::cl::init(true),
+    llvm::cl::Hidden,
+    llvm::cl::desc(
+        "Use the swift_task_dealloc_through symbol if it's available"));
+
+namespace {
+
+class GetDeallocThroughFn {
+  IRGenModule &IGM;
+  class Builder {
+    IRGenModule &IGM;
+    IRGenFunction &IGF;
+    bool isPointer8Bytes;
+
+  public:
+    Builder(IRGenFunction &IGF)
+        : IGM(IGF.IGM), IGF(IGF),
+          isPointer8Bytes(IGM.getPointerSize() == Size(8)) {
+      assert(!IGM.getAvailabilityRange().isContainedIn(
+                 IGM.Context.getCoroutineAccessorsAvailability()) ||
+             !EnableRuntimeTaskDeallocThrough);
+    }
+
+    /// Emit the function.
+    void build() {
+      auto parameters = IGF.collectParameters();
+      auto *ptr = parameters.claimNext();
+
+      if (EnableRuntimeTaskDeallocThrough) {
+        emitForwardToWeakRuntimeFunction(ptr);
+      }
+
+      auto allocationPtrAddr = emitOffsetIntoTask();
+
+      auto *loop = IGF.createBasicBlock("loop");
+      IGF.Builder.CreateBr(loop);
+
+      auto *exit = IGF.createBasicBlock("exit");
+      emitLoopBlock(loop, allocationPtrAddr, ptr, exit);
+      emitExitBlock(exit);
+    }
+
+  private:
+    /// Check whether the swift_task_dealloc_through is available and call it if
+    /// so.
+    void emitForwardToWeakRuntimeFunction(llvm::Value *ptr) {
+      auto runtimeFnValue = cast<llvm::Function>(IGM.getTaskDeallocThroughFn());
+      runtimeFnValue->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
+      auto *symbolExists = IGF.Builder.CreateICmpNE(
+          runtimeFnValue, llvm::ConstantPointerNull::get(IGF.IGM.PtrTy),
+          "runtime_has_dealloc_through");
+
+      auto *noSymbolBlock = IGF.createBasicBlock("no_runtime_symbol");
+      auto *hasSymbolBlock = IGF.createBasicBlock("runtime_symbol");
+
+      IGF.Builder.CreateCondBr(symbolExists, hasSymbolBlock, noSymbolBlock);
+
+      IGF.Builder.emitBlock(hasSymbolBlock);
+      IGF.Builder.CreateCall(
+          FunctionPointer::forDirect(
+              FunctionPointer::Kind::Function, runtimeFnValue, nullptr,
+              IGM.getTaskDeallocThroughFunctionPointer().getSignature()),
+          {ptr});
+      IGF.Builder.CreateRetVoid();
+
+      IGF.Builder.emitBlock(noSymbolBlock);
+      // The rest of the function will be emitted starting with this block.
+    }
+
+    /// Calculate the address (an offset into the current task) of the pointer
+    /// to the latest allocation.
+    ///
+    /// This calculation depends on the deployment target.  If it's new enough
+    /// (aligned with at least Swift 5.7), the "new" layouts can be used
+    /// unconditionally.  Otherwise, the old layout must be used when the OS is
+    /// aligned with a release before Swift 5.7.
+    Address emitOffsetIntoTask() {
+      auto *task = IGF.getAsyncTask();
+      if (!IGM.Context.getSwift57Availability().hasMinimumVersion()) {
+        return emitNewLayoutOffsetIntoTask(task);
+      }
+      auto deploymentRange =
+          AvailabilityRange::forDeploymentTarget(IGM.Context);
+      if (deploymentRange.isContainedIn(IGM.Context.getSwift57Availability())) {
+        return emitNewLayoutOffsetIntoTask(task);
+      }
+
+      auto *oldBlock = IGF.createBasicBlock("old_layout");
+      auto *newBlock = IGF.createBasicBlock("new_layout");
+      auto *mergeBlock = IGF.createBasicBlock("merge_layout");
+
+      auto *isAtLeast57 = emitSwift57VersionCheck();
+      IGF.Builder.CreateCondBr(isAtLeast57, newBlock, oldBlock);
+
+      IGF.Builder.emitBlock(oldBlock);
+      auto oldOffset = emitOldLayoutOffsetIntoTask(task);
+      IGF.Builder.CreateBr(mergeBlock);
+
+      IGF.Builder.emitBlock(newBlock);
+      auto newOffset = emitNewLayoutOffsetIntoTask(task);
+      IGF.Builder.CreateBr(mergeBlock);
+      auto *finalNewBlock = IGF.Builder.GetInsertBlock();
+
+      IGF.Builder.emitBlock(mergeBlock);
+      auto offsetPhi = IGF.Builder.CreatePHI(newOffset.getType(), 2);
+      offsetPhi->addIncoming(oldOffset.getAddress(), oldBlock);
+      offsetPhi->addIncoming(newOffset.getAddress(), finalNewBlock);
+      auto addressPhi =
+          Address(offsetPhi, oldOffset.getType(), oldOffset.getAlignment());
+      return addressPhi;
+    }
+
+    /// Given that the OS is aligned with a release before Swift 5.7, calculate
+    /// the address (an offset from \p task) of the pointer to the latest
+    /// allocation.
+    Address emitOldLayoutOffsetIntoTask(llvm::Value *task) {
+      if (!isPointer8Bytes) {
+        return computeOffsetIntoTask(
+            task, getTaskLayoutInfo(PrivateLayout::Old32Bit));
+      }
+      return computeOffsetIntoTask(task,
+                                   getTaskLayoutInfo(PrivateLayout::Old64Bit));
+    }
+
+    /// Given that the OS is aligned with at least Swift 5.7, calculate the
+    /// address (an offset from \p task) of the pointer to the latest
+    /// allocation.
+    Address emitNewLayoutOffsetIntoTask(llvm::Value *task) {
+      if (!isPointer8Bytes) {
+        return emitNew32BitOffsetIntoTask(task);
+      }
+      return computeOffsetIntoTask(task,
+                                   getTaskLayoutInfo(PrivateLayout::New64Bit));
+    }
+
+    /// Given that the target is 32-bit and the OS is Swift 5.7 aligned or
+    /// greater, calculate the address (an offset from \p task) of the pointer
+    /// to the latest allocation.
+    ///
+    /// This is complicated by the fact that the layout changes depending on
+    /// whether SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION is defined.  To
+    /// determine this, the existence of
+    /// _swift_concurrency_debug_supportsPriorityEscalation is checked.
+    Address emitNew32BitOffsetIntoTask(llvm::Value *task) {
+      auto *noEscalationBlock = IGF.createBasicBlock("escalation_no");
+      auto *yesEscalationBlock = IGF.createBasicBlock("escalation_yes");
+      auto *hasEscalationSymbolBlock =
+          IGF.createBasicBlock("escalation_has_symbol");
+      auto *mergeEscalationBlock = IGF.createBasicBlock("escalation_merge");
+
+      auto *escalationSymbol = IGF.IGM.Module.getOrInsertGlobal(
+          "_swift_concurrency_debug_supportsPriorityEscalation",
+          IGF.IGM.Int8Ty);
+      ApplyIRLinkage(IRLinkage::ExternalWeakImport)
+          .to(cast<llvm::GlobalVariable>(escalationSymbol));
+      auto *symbolExists = IGF.Builder.CreateICmpNE(
+          escalationSymbol, llvm::ConstantPointerNull::get(IGF.IGM.PtrTy),
+          "escalation_is_defined");
+
+      IGF.Builder.CreateCondBr(symbolExists, hasEscalationSymbolBlock,
+                               noEscalationBlock);
+      IGF.Builder.emitBlock(hasEscalationSymbolBlock);
+      auto escalationAddr =
+          Address(escalationSymbol, IGF.IGM.Int8Ty, Alignment(1));
+      auto *escalation = IGF.Builder.CreateLoad(escalationAddr, "escalation");
+      auto *escalationIsTrue = IGF.Builder.CreateICmpNE(
+          escalation, llvm::ConstantInt::get(IGF.IGM.Int8Ty, false),
+          "escalation_is_true");
+      IGF.Builder.CreateCondBr(escalationIsTrue, yesEscalationBlock,
+                               noEscalationBlock);
+
+      IGF.Builder.emitBlock(yesEscalationBlock);
+      auto escalationOffset = computeOffsetIntoTask(
+          task, getTaskLayoutInfo(PrivateLayout::New32BitWithEscalation));
+      IGF.Builder.CreateBr(mergeEscalationBlock);
+
+      IGF.Builder.emitBlock(noEscalationBlock);
+      auto noEscalationOffset = computeOffsetIntoTask(
+          task, getTaskLayoutInfo(PrivateLayout::New32BitSansEscalation));
+      IGF.Builder.CreateBr(mergeEscalationBlock);
+
+      IGF.Builder.emitBlock(mergeEscalationBlock);
+      auto offsetPhi = IGF.Builder.CreatePHI(noEscalationOffset.getType(), 2);
+      offsetPhi->addIncoming(noEscalationOffset.getAddress(),
+                             noEscalationBlock);
+      offsetPhi->addIncoming(escalationOffset.getAddress(), yesEscalationBlock);
+      auto addressPhi = Address(offsetPhi, noEscalationOffset.getType(),
+                                noEscalationOffset.getAlignment());
+      return addressPhi;
+    }
+
+    /// Calculate a bit suitable for a CondBr indicating that the OS is aligned
+    /// with Swift 5.7 or greater.
+    ///
+    /// This is relevant because the layout of Task changed from pre-5.7 to 5.7.
+    llvm::Value *emitSwift57VersionCheck() {
+      auto availability = IGM.Context.getSwift57Availability();
+      auto deploymentRange =
+          AvailabilityRange::forDeploymentTarget(IGM.Context);
+      assert(!deploymentRange.isContainedIn(availability));
+      (void)deploymentRange;
+      assert(availability.hasMinimumVersion());
+      // FIXME: [availability] This does not generate the correct query for
+      // macCatalyst or zippered targets (rdar://155999964).
+      auto version = availability.getRawMinimumVersion();
+      auto *major = getInt32Constant(version.getMajor());
+      auto *minor = getInt32Constant(version.getMinor());
+      auto *patch = getInt32Constant(version.getSubminor());
+
+      auto *isAtLeastValue =
+          IGF.emitTargetOSVersionAtLeastCall(major, minor, patch);
+
+      auto *isAtLeast = IGF.Builder.CreateICmpNE(
+          isAtLeastValue, llvm::Constant::getNullValue(IGM.Int32Ty));
+
+      return isAtLeast;
+    }
+
+    llvm::ConstantInt *getInt32Constant(std::optional<unsigned> value) {
+      return llvm::ConstantInt::get(IGM.Int32Ty, value.value_or(0));
+    };
+
+    /// Specifies a layout of the Task runtime struct, specifically just enough
+    /// of its private fields in order to find the pointer to the latest
+    /// allocation.
+    ///
+    /// There are two "flavors" of layouts:
+    /// Swift 5.6 and before:
+    /// class Task {
+    ///   AsyncContext * __ptrauth_swift_task_resume_context ResumeContext;
+    ///
+    ///   #if SWIFT_POINTER_IS_8_BYTES
+    ///   void *Reserved64;
+    ///   #endif
+    ///
+    ///   // May or may not have been visible in Task.h.
+    ///   swift::atomic<ActiveTaskStatus> Status;
+    ///   // Never directly visible in Task.h.
+    ///   TaskAllocator Allocator;
+    /// }
+    /// Swift 5.7 and after:
+    /// class Task {
+    ///   AsyncContext * __ptrauth_swift_task_resume_context ResumeContext;
+    ///
+    ///   #if SWIFT_POINTER_IS_8_BYTES
+    ///   void *Reserved64;
+    ///   #endif
+    ///
+    ///   // Always hidden via OpaquePrivateStorage.
+    ///   uintptr_t ExclusivityAccessSet[2] = {0, 0};
+    ///   // size here was always ((32-bit && escalating) ? 4 : 2) * word_size.
+    ///   alignas(ActiveTaskStatus) char StatusStorage[sizeof(ActiveTaskStatus)]
+    ///
+    ///   TaskAllocator Allocator;
+    /// }
+    struct PrivateLayout {
+      enum Kind {
+        Old32Bit,
+        Old64Bit,
+        New32BitSansEscalation,
+        New32BitWithEscalation,
+        New64Bit,
+      };
+      Kind kind;
+      PrivateLayout(Kind kind) : kind(kind) {}
+      bool isPointer8Bytes() {
+        switch (kind) {
+        case Old64Bit:
+        case New64Bit:
+          return true;
+        case Old32Bit:
+        case New32BitSansEscalation:
+        case New32BitWithEscalation:
+          return false;
+        }
+        llvm_unreachable("covered switch");
+      }
+      bool isOld() {
+        switch (kind) {
+        case Old32Bit:
+        case Old64Bit:
+          return true;
+        case New32BitSansEscalation:
+        case New32BitWithEscalation:
+        case New64Bit:
+          return false;
+        }
+        llvm_unreachable("covered switch");
+      }
+      unsigned activeTaskStatusSizeInWords() {
+        switch (kind) {
+        case Old32Bit:
+        case Old64Bit:
+          return 2;
+
+        // #if SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION &&
+        // SWIFT_POINTER_IS_4_BYTES #define ACTIVE_TASK_STATUS_SIZE (4 *
+        // (sizeof(uintptr_t))) #else #define ACTIVE_TASK_STATUS_SIZE (2 *
+        // (sizeof(uintptr_t))) #endif
+        case New32BitSansEscalation:
+          return 2;
+        case New32BitWithEscalation:
+          return 4;
+        case New64Bit:
+          return 2;
+        }
+        llvm_unreachable("covered switch");
+      }
+      struct Field {
+        enum Kind {
+          RefCountedStruct,
+          Int8Ptr,
+          Int32,
+          FunctionPtr,
+          SwiftContextPtr,
+          Ptr,
+          IntPtr,
+          AllocationPtr,
+        };
+        Kind kind;
+        Field(Kind kind) : kind(kind) {}
+        Size getSizeInBytes(Size wordSize) {
+          switch (kind) {
+          case RefCountedStruct:
+            return wordSize * 2;
+          case Int8Ptr:
+          case FunctionPtr:
+          case SwiftContextPtr:
+          case Ptr:
+          case IntPtr:
+            return wordSize;
+          case Int32:
+            return Size(4);
+          case AllocationPtr:
+            return wordSize;
+          }
+          llvm_unreachable("covered switch");
+        }
+        llvm::Type *getType(IRGenModule &IGM) {
+          switch (kind) {
+          case RefCountedStruct:
+            return IGM.RefCountedStructTy;
+          case Int8Ptr:
+            return IGM.Int8PtrTy;
+          case Int32:
+            return IGM.Int32Ty;
+          case FunctionPtr:
+            return IGM.FunctionPtrTy;
+          case SwiftContextPtr:
+            return IGM.SwiftContextPtrTy;
+          case Ptr:
+            return IGM.PtrTy;
+          case IntPtr:
+            return IGM.IntPtrTy;
+          case AllocationPtr:
+            return IGM.PtrTy;
+          }
+          llvm_unreachable("covered switch");
+        }
+      };
+      template <typename Impl>
+      struct FieldVisitor {
+        Impl &asImpl() { return *static_cast<Impl *>(this); }
+        void visit(PrivateLayout layout) {
+          asImpl().visitField(Field::RefCountedStruct); // object header
+          asImpl().visitField(Field::Int8Ptr);
+          asImpl().visitField(Field::Int8Ptr);     // Job.SchedulerPrivate
+          asImpl().visitField(Field::Int32);       // Job.Flags
+          asImpl().visitField(Field::Int32);       // Job.ID
+          asImpl().visitField(Field::Int8Ptr);     // Job.Voucher
+          asImpl().visitField(Field::Int8Ptr);     // Job.Reserved
+          asImpl().visitField(Field::FunctionPtr); // Job.RunJob/Job.ResumeTask
+          asImpl().visitField(Field::SwiftContextPtr); // Task.ResumeContext
+          if (layout.isPointer8Bytes()) {
+            // #if SWIFT_POINTER_IS_8_BYTES
+            //   void *Reserved64;
+            // #endif
+            asImpl().visitField(Field::Ptr);
+          }
+          if (layout.isOld()) {
+            //// May or may not have been visible in Task.h.
+            // swift::atomic<ActiveTaskStatus> Status;
+            asImpl().visitArray(Field::Ptr,
+                                layout.activeTaskStatusSizeInWords());
+          } else {
+            //// Always hidden via OpaquePrivateStorage.
+            // uintptr_t ExclusivityAccessSet[2] = {0, 0};
+            asImpl().visitArray(Field::IntPtr, 2);
+            //// The size here is always ((32-bit && escalating) ? 4 : 2) *
+            /// word_size.
+            // alignas(ActiveTaskStatus) char
+            // StatusStorage[sizeof(ActiveTaskStatus)];
+            asImpl().visitArray(Field::Ptr,
+                                layout.activeTaskStatusSizeInWords());
+          }
+          //// Never directly visible in Task.h.
+          // TaskAllocator Allocator;
+          //  The first field is always a pointer to the latest allocation.
+          asImpl().visitField(Field::AllocationPtr);
+        }
+      };
+      std::string getName() {
+        switch (kind) {
+        case Old32Bit:
+          return "swift.back_deploy.task.pre_57";
+        case Old64Bit:
+          return "swift.back_deploy.task.pre_57";
+        case New32BitSansEscalation:
+          return "swift.back_deploy.task.post_57.nonescalating";
+        case New32BitWithEscalation:
+          return "swift.back_deploy.task.post_57.escalating";
+        case New64Bit:
+          return "swift.back_deploy.task.post_57";
+        }
+        llvm_unreachable("covered switch");
+      };
+      void getFields(IRGenModule &IGM,
+                     SmallVectorImpl<llvm::Type *> &fieldTys) {
+        struct Visitor : PrivateLayout::FieldVisitor<Visitor> {
+          SmallVectorImpl<llvm::Type *> &fieldTys;
+          IRGenModule &IGM;
+          Visitor(SmallVectorImpl<llvm::Type *> &fieldTys, IRGenModule &IGM)
+              : fieldTys(fieldTys), IGM(IGM) {}
+
+          void visitField(PrivateLayout::Field field) {
+            fieldTys.push_back(field.getType(IGM));
+          };
+          void visitArray(PrivateLayout::Field field, unsigned count) {
+            fieldTys.push_back(llvm::ArrayType::get(field.getType(IGM), count));
+          }
+        };
+
+        Visitor visitor(fieldTys, IGM);
+        visitor.visit(*this);
+      }
+      unsigned getAllocatorIndex() {
+        struct Visitor : FieldVisitor<Visitor> {
+          unsigned index = 0;
+          void visitField(PrivateLayout::Field field) {
+            if (field.kind == Field::AllocationPtr)
+              return;
+            index++;
+          };
+          void visitArray(PrivateLayout::Field field, unsigned count) {
+            index++;
+          }
+        };
+        Visitor visitor;
+        visitor.visit(*this);
+        return visitor.index;
+      }
+      Size getAllocatorOffset(IRGenModule &IGM) {
+        struct Visitor : FieldVisitor<Visitor> {
+          Size wordSize;
+          Size offset;
+          Visitor(Size wordSize) : wordSize(wordSize), offset(0) {}
+          void visitField(PrivateLayout::Field field) {
+            if (field.kind == Field::AllocationPtr)
+              return;
+            offset += field.getSizeInBytes(wordSize);
+          };
+          void visitArray(PrivateLayout::Field field, unsigned count) {
+            offset += field.getSizeInBytes(wordSize) * count;
+          }
+        };
+        Visitor visitor(IGM.getPointerSize());
+        visitor.visit(*this);
+        return Size(visitor.offset);
+      }
+    };
+
+    llvm::DenseMap<PrivateLayout::Kind, llvm::StructType *> extendedTaskTys;
+    llvm::StructType *getExtendedSwiftTaskTy(PrivateLayout layout) {
+      auto iterator = extendedTaskTys.find(layout.kind);
+      if (iterator != extendedTaskTys.end())
+        return iterator->second;
+
+      assert(layout.isPointer8Bytes() == isPointer8Bytes);
+
+      SmallVector<llvm::Type *, 16> fieldTys;
+      layout.getFields(IGM, fieldTys);
+
+      auto name = layout.getName();
+      return llvm::StructType::create(IGM.getLLVMContext(), fieldTys, name,
+                                      /*packed*/ false);
+    }
+
+    llvm::StructType *_allocationTy = nullptr;
+    /// The type of the allocation to which there's a pointer within the Task.
+    llvm::StructType *getAllocationTy() {
+      if (!_allocationTy) {
+        _allocationTy = IGM.createTransientStructType(
+            "swift.back_deploy.task.stack_allocator.allocation",
+            {// Allocation *previous;
+             IGM.PtrTy,
+             // Slab *slab;
+             IGM.PtrTy});
+      }
+      return _allocationTy;
+    }
+
+    /// The facts about the layout of Task in some PrivateLayout that will
+    /// allow the offset to the address of the latest allocation to be
+    /// calculated.
+    struct TaskLayoutInfo {
+      llvm::StructType *ty;
+      unsigned allocationIndex;
+      Size allocationOffset;
+    };
+    TaskLayoutInfo getTaskLayoutInfo(PrivateLayout layout) {
+      return {getExtendedSwiftTaskTy(layout), layout.getAllocatorIndex(),
+              layout.getAllocatorOffset(IGM)};
+    };
+
+    /// Calculate the address of the pointer to the latest allocation.  It's an
+    /// offset from \p task determined by \p info.
+    Address computeOffsetIntoTask(llvm::Value *task, TaskLayoutInfo info) {
+      auto taskAddr = Address(task, info.ty, IGF.IGM.getPointerAlignment());
+      auto allocationPtrAddr = IGF.Builder.CreateStructGEP(
+          taskAddr, info.allocationIndex, info.allocationOffset);
+      return allocationPtrAddr;
+    }
+
+    /// Load the \p allocationPtrAddr and offset from it to calculate the latest
+    /// allocated memory.  Pass that allocated memory to swift_task_dealloc.
+    ///
+    /// If this allocated memory is the memory we are deallocating "through"
+    /// (i.e \p ptr), then we're done (i.e. br \p exit).  Otherwise, keep going
+    /// (i.e. br \p loop).
+    void emitLoopBlock(llvm::BasicBlock *loop, Address allocationPtrAddr,
+                       llvm::Value *ptr, llvm::BasicBlock *exit) {
+      IGF.Builder.emitBlock(loop);
+      auto allocationAddr =
+          IGF.Builder.CreateLoad(allocationPtrAddr, "allocation");
+      auto headerSize = IGF.alignUpToMaximumAlignment(
+          IGM.SizeTy, llvm::ConstantInt::get(
+                          IGM.IntPtrTy, 2 * IGM.getPointerSize().getValue()));
+      auto *current = IGF.Builder.CreateInBoundsGEP(IGM.Int8Ty, allocationAddr,
+                                                    {headerSize});
+
+      IGF.Builder.CreateCall(IGM.getTaskDeallocFunctionPointer(), {current});
+
+      auto *currentIsntPtr =
+          IGF.Builder.CreateICmpNE(current, ptr, "current_is_not_ptr");
+      IGF.Builder.CreateCondBr(currentIsntPtr, loop, exit);
+    }
+
+    /// Return void.
+    void emitExitBlock(llvm::BasicBlock *exit) {
+      // Emit the exit block.
+      IGF.Builder.emitBlock(exit);
+      IGF.Builder.CreateRetVoid();
+    }
+  };
+
+public:
+  GetDeallocThroughFn(IRGenModule &IGM) : IGM(IGM) {}
+  llvm::Constant *get() {
+    if (EnableRuntimeTaskDeallocThrough &&
+        IGM.getAvailabilityRange().isContainedIn(
+            IGM.Context.getCoroutineAccessorsAvailability())) {
+      // For high enough deployment targets, just use the runtime entry point.
+      return IGM.getTaskDeallocThroughFn();
+    }
+    return IGM.getOrCreateHelperFunction(
+        "_swift_task_dealloc_through", IGM.VoidTy, {IGM.Int8PtrTy},
+        [](auto &IGF) { Builder(IGF).build(); },
+        /*setIsNoInline=*/true,
+        /*forPrologue=*/false,
+        /*isPerformanceConstraint=*/false,
+        /*optionalLinkageOverride=*/nullptr, IGM.SwiftCC);
+  }
+};
+
+} // end anonymous namespace
+
+void IRGenFunction::emitTaskDeallocThrough(Address address) {
+  auto getDeallocThroughFn = GetDeallocThroughFn(IGM);
+  auto fnPtr = FunctionPointer::forDirect(
+      FunctionPointer::Kind::Function, getDeallocThroughFn.get(), nullptr,
+      IGM.getTaskDeallocThroughFunctionPointer().getSignature());
+  auto *call = Builder.CreateCall(fnPtr, {address.getAddress()});
+  call->setDoesNotThrow();
+  call->setCallingConv(IGM.SwiftCC);
+}
diff --git a/lib/IRGen/GenDecl.cpp b/lib/IRGen/GenDecl.cpp
index e08d5af96ae9a..d1e16ec46aeb9 100644
--- a/lib/IRGen/GenDecl.cpp
+++ b/lib/IRGen/GenDecl.cpp
@@ -296,9 +296,9 @@ class ObjCProtocolInitializerVisitor
     // Check if the ObjC runtime already has a descriptor for this
     // protocol. If so, use it.
     SmallString<32> buf;
-    auto protocolName
-      = IGM.getAddrOfGlobalString(proto->getObjCRuntimeName(buf));
-    
+    auto protocolName = IGM.getAddrOfGlobalString(
+        proto->getObjCRuntimeName(buf), CStringSectionType::ObjCClassName);
+
     auto existing = Builder.CreateCall(objc_getProtocol, protocolName);
     auto isNull = Builder.CreateICmpEQ(existing,
                    llvm::ConstantPointerNull::get(IGM.ProtocolDescriptorPtrTy));
@@ -344,8 +344,7 @@ class ObjCProtocolInitializerVisitor
 
     llvm::Value *ref =
         IGM.getAddrOfObjCProtocolRef(proto, NotForDefinition).getAddress();
-    ref = IGF.Builder.CreateBitCast(ref,
-                                  IGM.ProtocolDescriptorPtrTy->getPointerTo());
+    ref = IGF.Builder.CreateBitCast(ref, IGM.PtrTy);
 
     Builder.CreateStore(result, ref, IGM.getPointerAlignment());
   }
@@ -1057,16 +1056,14 @@ void IRGenModule::SetCStringLiteralSection(llvm::GlobalVariable *GV,
   case llvm::Triple::MachO:
     switch (Type) {
     case ObjCLabelType::ClassName:
-      GV->setSection("__TEXT,__objc_classname,cstring_literals");
+      GV->setSection(IRGenModule::ObjCClassNameSectionName);
       return;
     case ObjCLabelType::MethodVarName:
-      GV->setSection("__TEXT,__objc_methname,cstring_literals");
+    case ObjCLabelType::PropertyName:
+      GV->setSection(IRGenModule::ObjCMethodNameSectionName);
       return;
     case ObjCLabelType::MethodVarType:
-      GV->setSection("__TEXT,__objc_methtype,cstring_literals");
-      return;
-    case ObjCLabelType::PropertyName:
-      GV->setSection("__TEXT,__cstring,cstring_literals");
+      GV->setSection(IRGenModule::ObjCMethodTypeSectionName);
       return;
     }
   case llvm::Triple::ELF:
@@ -1157,9 +1154,17 @@ static bool isLazilyEmittedFunction(SILFunction &f, SILModule &m) {
       f.getLoweredFunctionType()->getSubstGenericSignature()) {
     return true;
   }
-  
-  if (f.isPossiblyUsedExternally())
+
+  if (f.isPossiblyUsedExternally()) {
+    // Under the embedded linkage model, if it has a non-unique definition,
+    // treat it lazily.
+    if (f.hasNonUniqueDefinition() && !f.isSwiftRuntimeFunction()
+        && !f.markedAsUsed()) {
+      return true;
+    }
+
     return false;
+  }
 
   if (f.getDynamicallyReplacedFunction())
     return false;
@@ -1167,6 +1172,21 @@ static bool isLazilyEmittedFunction(SILFunction &f, SILModule &m) {
   return true;
 }
 
+// Eagerly emit global variables that are externally visible.
+static bool isLazilyEmittedGlobalVariable(SILGlobalVariable &v, SILModule &m) {
+  if (v.isPossiblyUsedExternally()) {
+    // Under the embedded linkage model, if it has a non-unique definition,
+    // treat it lazily.
+    if (v.hasNonUniqueDefinition() && !v.markedAsUsed()) {
+      return true;
+    }
+
+    return false;
+  }
+
+  return true;
+}
+
 void IRGenerator::emitGlobalTopLevel(
     const std::vector<std::string> &linkerDirectives) {
   if (PrimaryIGM->getSILModule().getOptions().StopOptimizationAfterSerialization) {
@@ -1200,6 +1220,9 @@ void IRGenerator::emitGlobalTopLevel(
     createLinkerDirectiveVariable(*PrimaryIGM, directive);
   }
   for (SILGlobalVariable &v : PrimaryIGM->getSILModule().getSILGlobals()) {
+    if (isLazilyEmittedGlobalVariable(v, PrimaryIGM->getSILModule()))
+      continue;
+
     Decl *decl = v.getDecl();
     CurrentIGMPtr IGM = getGenModule(decl ? decl->getDeclContext() : nullptr);
     IGM->emitSILGlobalVariable(&v);
@@ -1361,6 +1384,7 @@ void IRGenerator::emitLazyDefinitions() {
          !LazyExtensionDescriptors.empty() ||
          !LazyFieldDescriptors.empty() ||
          !LazyFunctionDefinitions.empty() || !LazyWitnessTables.empty() ||
+         !LazyGlobalVariables.empty() ||
          !LazyCanonicalSpecializedMetadataAccessors.empty() ||
          !LazyMetadataAccessors.empty() ||
          !LazyClassMetadata.empty() ||
@@ -1449,6 +1473,13 @@ void IRGenerator::emitLazyDefinitions() {
       IGM->emitSILFunction(f);
     }
 
+    // Emit any lazy global variables we require.
+    while (!LazyGlobalVariables.empty()) {
+      SILGlobalVariable *v = LazyGlobalVariables.pop_back_val();
+      CurrentIGMPtr IGM = getGenModule(v);
+      IGM->emitSILGlobalVariable(v);
+    }
+
     while (!LazyCanonicalSpecializedMetadataAccessors.empty()) {
       CanType theType =
           LazyCanonicalSpecializedMetadataAccessors.pop_back_val();
@@ -1522,6 +1553,26 @@ void IRGenerator::addLazyFunction(SILFunction *f) {
   DefaultIGMForFunction.insert(std::make_pair(f, CurrentIGM));
 }
 
+void IRGenerator::addLazyGlobalVariable(SILGlobalVariable *v) {
+  // Add it to the queue if it hasn't already been put there.
+  if (!LazilyEmittedGlobalVariables.insert(v).second)
+    return;
+
+  assert(!FinishedEmittingLazyDefinitions);
+  LazyGlobalVariables.push_back(v);
+
+  if (auto decl = v->getDecl()) {
+    if (decl->getDeclContext()->getParentSourceFile())
+      return;
+  }
+
+  if (CurrentIGM == nullptr)
+    return;
+
+  // Don't update the map if we already have an entry.
+  DefaultIGMForGlobalVariable.insert(std::make_pair(v, CurrentIGM));
+}
+
 bool IRGenerator::hasLazyMetadata(TypeDecl *type) {
   assert(isa<NominalTypeDecl>(type) ||
          isa<OpaqueTypeDecl>(type));
@@ -1992,6 +2043,7 @@ void IRGenerator::emitDynamicReplacements() {
       "\x01l_auto_dynamic_replacements", IGM.getPointerAlignment(),
       /*isConstant*/ true, llvm::GlobalValue::PrivateLinkage);
   autoReplVar->setSection(getDynamicReplacementSection(IGM));
+  disableAddressSanitizer(IGM, autoReplVar);
   IGM.addUsedGlobal(autoReplVar);
 
   if (origFuncTypes.empty())
@@ -2245,7 +2297,8 @@ void IRGenerator::emitEntryPointInfo() {
 static IRLinkage
 getIRLinkage(StringRef name, const UniversalLinkageInfo &info,
              SILLinkage linkage, ForDefinition_t isDefinition,
-             bool isWeakImported, bool isKnownLocal = false) {
+             bool isWeakImported, bool isKnownLocal,
+             bool hasNonUniqueDefinition) {
 #define RESULT(LINKAGE, VISIBILITY, DLL_STORAGE)                               \
   IRLinkage{llvm::GlobalValue::LINKAGE##Linkage,                               \
             llvm::GlobalValue::VISIBILITY##Visibility,                         \
@@ -2276,8 +2329,13 @@ getIRLinkage(StringRef name, const UniversalLinkageInfo &info,
   case SILLinkage::Package: {
     auto linkage = llvm::GlobalValue::ExternalLinkage;
 
-    if (info.MergeableSymbols)
-      linkage = llvm::GlobalValue::WeakODRLinkage;
+    if (hasNonUniqueDefinition) {
+      // Keep Swift runtime functions around so IRGen can reference them.
+      if (SILFunction::isSwiftRuntimeFunction(name, nullptr))
+        linkage = llvm::GlobalValue::WeakODRLinkage;
+      else
+        linkage = llvm::GlobalValue::LinkOnceODRLinkage;
+    }
 
     return {linkage, PublicDefinitionVisibility,
             info.Internalize ? llvm::GlobalValue::DefaultStorageClass
@@ -2294,15 +2352,15 @@ getIRLinkage(StringRef name, const UniversalLinkageInfo &info,
                         : RESULT(External, Hidden, Default);
 
   case SILLinkage::Hidden:
-    if (info.MergeableSymbols)
-      return RESULT(WeakODR, Hidden, Default);
+    if (hasNonUniqueDefinition)
+      return RESULT(LinkOnceODR, Hidden, Default);
 
     return RESULT(External, Hidden, Default);
 
   case SILLinkage::Private: {
     if (info.forcePublicDecls() && !isDefinition)
       return getIRLinkage(name, info, SILLinkage::PublicExternal, isDefinition,
-                          isWeakImported, isKnownLocal);
+                          isWeakImported, isKnownLocal, hasNonUniqueDefinition);
 
     auto linkage = info.needLinkerToMergeDuplicateSymbols()
                        ? llvm::GlobalValue::LinkOnceODRLinkage
@@ -2358,7 +2416,8 @@ void irgen::updateLinkageForDefinition(IRGenModule &IGM,
   auto IRL =
       getIRLinkage(global->hasName() ? global->getName() : StringRef(),
                    linkInfo, entity.getLinkage(ForDefinition), ForDefinition,
-                   weakImported, isKnownLocal);
+                   weakImported, isKnownLocal,
+                   entity.hasNonUniqueDefinition());
   ApplyIRLinkage(IRL).to(global);
 
   LinkInfo link = LinkInfo::get(IGM, entity, ForDefinition);
@@ -2411,7 +2470,8 @@ LinkInfo LinkInfo::get(const UniversalLinkageInfo &linkInfo,
   bool weakImported = entity.isWeakImported(swiftModule);
   result.IRL = getIRLinkage(result.Name, linkInfo,
                             entity.getLinkage(isDefinition), isDefinition,
-                            weakImported, isKnownLocal);
+                            weakImported, isKnownLocal,
+                            entity.hasNonUniqueDefinition());
   result.ForDefinition = isDefinition;
   return result;
 }
@@ -2422,7 +2482,8 @@ LinkInfo LinkInfo::get(const UniversalLinkageInfo &linkInfo, StringRef name,
   LinkInfo result;
   result.Name += name;
   result.IRL = getIRLinkage(name, linkInfo, linkage, isDefinition,
-                            isWeakImported, linkInfo.Internalize);
+                            isWeakImported, linkInfo.Internalize,
+                            /*hasNonUniqueDefinition=*/false);
   result.ForDefinition = isDefinition;
   return result;
 }
@@ -2661,6 +2722,9 @@ void IRGenModule::emitGlobalDecl(Decl *D) {
   case DeclKind::MacroExpansion:
     // Expansion already visited as auxiliary decls.
     return;
+
+  case DeclKind::Using:
+    return;
   }
 
   llvm_unreachable("bad decl kind!");
@@ -2690,13 +2754,15 @@ Address IRGenModule::getAddrOfSILGlobalVariable(SILGlobalVariable *var,
     // If we're not emitting this to define it, make sure we cast it to the
     // right type.
     if (!forDefinition) {
-      auto ptrTy = ti.getStorageType()->getPointerTo();
-      addr = llvm::ConstantExpr::getBitCast(addr, ptrTy);
+      addr = llvm::ConstantExpr::getBitCast(addr, PtrTy);
     }
 
     auto alignment =
       Alignment(getClangASTContext().getDeclAlign(clangDecl).getQuantity());
     return Address(addr, ti.getStorageType(), alignment);
+  } else if (!forDefinition &&
+             isLazilyEmittedGlobalVariable(*var, getSILModule())) {
+    IRGen.addLazyGlobalVariable(var);
   }
 
   ResilienceExpansion expansion = getResilienceExpansionForLayout(var);
@@ -2709,7 +2775,7 @@ Address IRGenModule::getAddrOfSILGlobalVariable(SILGlobalVariable *var,
 
   if (var->isInitializedObject()) {
     assert(ti.isFixedSize(expansion));
-    StructLayout *Layout = StaticObjectLayouts[var].get();
+    StructLayout *Layout = StaticObjectLayouts[var].layout.get();
     if (!Layout) {
       // Create the layout (includes the llvm type) for the statically
       // initialized object and store it for later.
@@ -2720,7 +2786,7 @@ Address IRGenModule::getAddrOfSILGlobalVariable(SILGlobalVariable *var,
       }
       Layout = getClassLayoutWithTailElems(*this,
                                            var->getLoweredType(), TailTypes);
-      StaticObjectLayouts[var] = std::unique_ptr<StructLayout>(Layout);
+      StaticObjectLayouts[var] = {std::unique_ptr<StructLayout>(Layout), nullptr};
     }
     storageType = Layout->getType();
     fixedSize = Layout->getSize();
@@ -2778,9 +2844,9 @@ Address IRGenModule::getAddrOfSILGlobalVariable(SILGlobalVariable *var,
       }
 
       DebugTypeInfo DbgTy =
-          inFixedBuffer ? DebugTypeInfo::getGlobalFixedBuffer(var, fixedSize,
-                                                              fixedAlignment)
-                        : DebugTypeInfo::getGlobal(var, *this);
+          inFixedBuffer
+              ? DebugTypeInfo::getGlobalFixedBuffer(var, fixedAlignment, *this)
+              : DebugTypeInfo::getGlobal(var, *this);
 
       gvar = createVariable(*this, link, globalTy, fixedAlignment, DbgTy, loc, name);
     }
@@ -2825,8 +2891,7 @@ Address IRGenModule::getAddrOfSILGlobalVariable(SILGlobalVariable *var,
   }
 
   addr = llvm::ConstantExpr::getBitCast(
-      addr,
-      castStorageToType ? castStorageToType : storageType->getPointerTo());
+      addr, castStorageToType ? castStorageToType : PtrTy);
   if (castStorageToType)
     storageType = cast<ClassTypeInfo>(ti).getClassLayoutType();
 
@@ -2837,7 +2902,7 @@ llvm::Constant *IRGenModule::getGlobalInitValue(SILGlobalVariable *var,
                                                 llvm::Type *storageType,
                                                 Alignment alignment) {
   if (var->isInitializedObject()) {
-    StructLayout *layout = StaticObjectLayouts[var].get();
+    StructLayout *layout = StaticObjectLayouts[var].layout.get();
     ObjectInst *oi = cast<ObjectInst>(var->getStaticInitializerValue());
     llvm::Constant *initVal = emitConstantObject(*this, oi, layout);
     if (!canMakeStaticObjectReadOnly(var->getLoweredType())) {
@@ -2847,13 +2912,18 @@ llvm::Constant *IRGenModule::getGlobalInitValue(SILGlobalVariable *var,
       //       swift_once_t token[fixedAlignment / sizeof(swift_once_t)];
       //       HeapObject object;
       //     };
-      std::string typeName = storageType->getStructName().str() + 'c';
-      assert(alignment >= getPointerAlignment());
-      unsigned numTokens = alignment.getValue() /
-                           getPointerAlignment().getValue();
-      auto *containerTy = llvm::StructType::create(getLLVMContext(),
-              {llvm::ArrayType::get(OnceTy, numTokens), initVal->getType()},
-              typeName);
+      llvm::StructType *containerTy = StaticObjectLayouts[var].containerTy;
+      if (!containerTy) {
+        std::string typeName = storageType->getStructName().str() + 'c';
+        assert(alignment >= getPointerAlignment());
+        unsigned numTokens = alignment.getValue() /
+                             getPointerAlignment().getValue();
+        containerTy = llvm::StructType::create(getLLVMContext(),
+                {llvm::ArrayType::get(OnceTy, numTokens), initVal->getType()},
+                typeName);
+        StaticObjectLayouts[var].containerTy = containerTy;
+      }
+
       auto *zero = llvm::ConstantAggregateZero::get(containerTy->getElementType(0));
       initVal = llvm::ConstantStruct::get(containerTy, {zero , initVal});
     }
@@ -2928,6 +2998,7 @@ static void addLLVMFunctionAttributes(SILFunction *f, Signature &signature) {
     attrs = attrs.addFnAttribute(signature.getType()->getContext(),
                                  llvm::Attribute::NoInline);
     break;
+  case HeuristicAlwaysInline:
   case AlwaysInline:
     // FIXME: We do not currently transfer AlwaysInline since doing so results
     // in test failures, which must be investigated first.
@@ -3023,8 +3094,7 @@ void IRGenModule::createReplaceableProlog(IRGenFunction &IGF, SILFunction *f) {
       linkEntry->getValueType(), linkEntry, indices);
 
   auto *ReplAddr =
-    llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(fnPtrAddr,
-      FunctionPtrTy->getPointerTo());
+      llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(fnPtrAddr, PtrTy);
 
   auto *FnAddr = llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
       funPtr, FunctionPtrTy);
@@ -3065,7 +3135,7 @@ void IRGenModule::createReplaceableProlog(IRGenFunction &IGF, SILFunction *f) {
     PrologueLocation AutoRestore(IGM.DebugInfo.get(), Builder);
     auto authEntity = PointerAuthEntity(f);
     auto authInfo = PointerAuthInfo::emit(IGF, schema, fnPtrAddr, authEntity);
-    auto *fnType = signature.getType()->getPointerTo();
+    auto *fnType = PtrTy;
     auto *realReplFn = Builder.CreateBitCast(ReplFn, fnType);
     auto asyncFnPtr = FunctionPointer::createSigned(silFunctionType, realReplFn,
                                                     authInfo, signature);
@@ -3188,7 +3258,7 @@ void IRGenModule::createReplaceableProlog(IRGenFunction &IGF, SILFunction *f) {
     SmallVector<llvm::Value *, 16> forwardedArgs;
     for (auto &arg : IGF.CurFn->args())
       forwardedArgs.push_back(&arg);
-    auto *fnType = signature.getType()->getPointerTo();
+    auto *fnType = PtrTy;
     auto *realReplFn = IGF.Builder.CreateBitCast(ReplFn, fnType);
 
     auto authEntity = PointerAuthEntity(f);
@@ -3370,7 +3440,7 @@ void IRGenModule::emitDynamicReplacementOriginalFunctionThunk(SILFunction *f) {
   auto *fnPtrAddr = llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
       llvm::ConstantExpr::getInBoundsGetElementPtr(linkEntry->getValueType(),
                                                    linkEntry, indices),
-      FunctionPtrTy->getPointerTo());
+      PtrTy);
 
   auto *OrigFn = IGF.Builder.CreateCall(
       getGetOrigOfReplaceableFunctionPointer(), {fnPtrAddr});
@@ -3733,13 +3803,15 @@ static llvm::GlobalVariable *createGOTEquivalent(IRGenModule &IGM,
                                       llvm::GlobalValue::PrivateLinkage,
                                       global,
                                       llvm::Twine("got.") + globalName);
-  
+
   // rdar://problem/53836960: i386 ld64 also mis-links relative references
   // to GOT entries.
   // rdar://problem/59782487: issue with on-device JITd expressions.
   // The JIT gets confused by private vars accessed across object files.
+  // rdar://148168098: ELF x86 GOTPCREL relaxation can break metadata.
   if (!IGM.getOptions().UseJIT &&
-      (!IGM.Triple.isOSDarwin() || IGM.Triple.getArch() != llvm::Triple::x86)) {
+      (!IGM.Triple.isOSDarwin() || IGM.Triple.getArch() != llvm::Triple::x86) &&
+      (!IGM.Triple.isOSBinFormatELF() || !IGM.Triple.isX86())) {
     gotEquivalent->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
   } else {
     ApplyIRLinkage(IRLinkage::InternalLinkOnceODR)
@@ -3788,12 +3860,13 @@ llvm::Constant *IRGenModule::getOrCreateGOTEquivalent(llvm::Constant *global,
   return gotEquivalent;
 }
 
-static llvm::Constant *getElementBitCast(llvm::GlobalValue *ptr,
+static llvm::Constant *getElementBitCast(IRGenModule &IGM,
+                                         llvm::GlobalValue *ptr,
                                          llvm::Type *newEltType) {
   if (ptr->getValueType() == newEltType) {
     return ptr;
   } else {
-    auto newPtrType = newEltType->getPointerTo(
+    auto newPtrType = IGM.getOpaquePointerType(
         cast<llvm::PointerType>(ptr->getType())->getAddressSpace());
     return llvm::ConstantExpr::getBitCast(ptr, newPtrType);
   }
@@ -3906,7 +3979,7 @@ IRGenModule::getAddrOfLLVMVariable(LinkEntity entity,
     // Otherwise, we have a previous declaration or definition which
     // we need to ensure has the right type.
     } else {
-      return getElementBitCast(existing, defaultType);
+      return getElementBitCast(*this, existing, defaultType);
     }
   }
 
@@ -3915,7 +3988,7 @@ IRGenModule::getAddrOfLLVMVariable(LinkEntity entity,
 
   // Clang may have defined the variable already.
   if (auto existing = Module.getNamedGlobal(link.getName())) {
-    auto var = getElementBitCast(existing, defaultType);
+    auto var = getElementBitCast(*this, existing, defaultType);
     GlobalVars[entity] = var;
     return var;
   }
@@ -3960,16 +4033,21 @@ IRGenModule::getAddrOfLLVMVariable(LinkEntity entity,
   // inside the standard library with the definition being in the runtime
   // preventing the normal detection from identifying that this is module
   // local.
-  if (getSwiftModule()->isStdlibModule())
+  //
+  // If we are statically linking the standard library, we need to internalise
+  // the symbols.
+  if (getSwiftModule()->isStdlibModule() ||
+      (Context.getStdlibModule() &&
+       Context.getStdlibModule()->isStaticLibrary()))
     if (entity.isTypeKind() &&
         (IsWellKnownBuiltinOrStructralType(entity.getType()) ||
          entity.getType() == kAnyFunctionType))
       if (auto *GV = dyn_cast<llvm::GlobalValue>(var))
-          if (GV->hasDLLImportStorageClass())
-            ApplyIRLinkage({llvm::GlobalValue::ExternalLinkage,
-                            llvm::GlobalValue::DefaultVisibility,
-                            llvm::GlobalValue::DefaultStorageClass})
-                .to(GV);
+        if (GV->hasDLLImportStorageClass())
+          ApplyIRLinkage({llvm::GlobalValue::ExternalLinkage,
+                          llvm::GlobalValue::DefaultVisibility,
+                          llvm::GlobalValue::DefaultStorageClass})
+              .to(GV);
 
   // Install the concrete definition if we have one.
   if (definition && definition.hasInit()) {
@@ -4166,9 +4244,10 @@ static TypeEntityReference
 getObjCClassByNameReference(IRGenModule &IGM, ClassDecl *cls) {
   auto kind = TypeReferenceKind::DirectObjCClassName;
   SmallString<64> objcRuntimeNameBuffer;
-  auto ref = IGM.getAddrOfGlobalString(
-                                 cls->getObjCRuntimeName(objcRuntimeNameBuffer),
-                                 /*willBeRelativelyAddressed=*/true);
+  auto ref =
+      IGM.getAddrOfGlobalString(cls->getObjCRuntimeName(objcRuntimeNameBuffer),
+                                CStringSectionType::ObjCClassName,
+                                /*willBeRelativelyAddressed=*/true);
 
   return TypeEntityReference(kind, ref);
 }
@@ -4725,9 +4804,9 @@ void IRGenModule::emitAccessibleFunction(StringRef sectionName,
 
   // -- Field: Name (record name)
   {
-    llvm::Constant *name =
-        getAddrOfGlobalString(func.getFunctionName(),
-                              /*willBeRelativelyAddressed=*/true);
+    llvm::Constant *name = getAddrOfGlobalString(
+        func.getFunctionName(), CStringSectionType::Default,
+        /*willBeRelativelyAddressed=*/true);
     fields.addRelativeAddress(name);
   }
 
@@ -5793,6 +5872,7 @@ void IRGenModule::emitNestedTypeDecls(DeclRange members) {
     case DeclKind::Param:
     case DeclKind::Module:
     case DeclKind::PrecedenceGroup:
+    case DeclKind::Using:
       llvm_unreachable("decl not allowed in type context");
 
     case DeclKind::BuiltinTuple:
@@ -5922,9 +6002,8 @@ void IRGenModule::emitExtension(ExtensionDecl *ext) {
 Address IRGenFunction::createAlloca(llvm::Type *type,
                                     Alignment alignment,
                                     const llvm::Twine &name) {
-  llvm::AllocaInst *alloca =
-      new llvm::AllocaInst(type, IGM.DataLayout.getAllocaAddrSpace(), name,
-                           AllocaIP);
+  llvm::AllocaInst *alloca = new llvm::AllocaInst(
+      type, IGM.DataLayout.getAllocaAddrSpace(), name, AllocaIP->getIterator());
   alloca->setAlignment(llvm::MaybeAlign(alignment.getValue()).valueOrOne());
   return Address(alloca, type, alignment);
 }
@@ -5934,9 +6013,10 @@ Address IRGenFunction::createAlloca(llvm::Type *type,
                                     llvm::Value *ArraySize,
                                     Alignment alignment,
                                     const llvm::Twine &name) {
-  llvm::AllocaInst *alloca = new llvm::AllocaInst(
-      type, IGM.DataLayout.getAllocaAddrSpace(), ArraySize,
-      llvm::MaybeAlign(alignment.getValue()).valueOrOne(), name, AllocaIP);
+  llvm::AllocaInst *alloca =
+      new llvm::AllocaInst(type, IGM.DataLayout.getAllocaAddrSpace(), ArraySize,
+                           llvm::MaybeAlign(alignment.getValue()).valueOrOne(),
+                           name, AllocaIP->getIterator());
   return Address(alloca, type, alignment);
 }
 
@@ -5948,15 +6028,35 @@ Address IRGenFunction::createAlloca(llvm::Type *type,
 /// FIXME: willBeRelativelyAddressed is only needed to work around an ld64 bug
 /// resolving relative references to coalesceable symbols.
 /// It should be removed when fixed. rdar://problem/22674524
-llvm::Constant *IRGenModule::getAddrOfGlobalString(StringRef data,
-                                               bool willBeRelativelyAddressed,
-                                               bool useOSLogSection) {
-  useOSLogSection = useOSLogSection &&
-    TargetInfo.OutputObjectFormat == llvm::Triple::MachO;
+llvm::Constant *
+IRGenModule::getAddrOfGlobalString(StringRef data, CStringSectionType type,
+                                   bool willBeRelativelyAddressed) {
+  if (TargetInfo.OutputObjectFormat != llvm::Triple::MachO ||
+      willBeRelativelyAddressed)
+    type = CStringSectionType::Default;
+  StringRef sectionName;
+  switch (type) {
+  case CStringSectionType::Default:
+    sectionName = "";
+    break;
+  case CStringSectionType::ObjCClassName:
+    sectionName = ObjCClassNameSectionName;
+    break;
+  case CStringSectionType::ObjCMethodName:
+    sectionName = ObjCMethodNameSectionName;
+    break;
+  case CStringSectionType::ObjCMethodType:
+    sectionName = ObjCMethodTypeSectionName;
+    break;
+  case CStringSectionType::OSLogString:
+    sectionName = OSLogStringSectionName;
+    break;
+  case CStringSectionType::NumTypes:
+    llvm_unreachable("invalid type");
+  }
 
   // Check whether this string already exists.
-  auto &entry = useOSLogSection ? GlobalOSLogStrings[data] :
-    GlobalStrings[data];
+  auto &entry = GlobalStrings[static_cast<size_t>(type)][data];
 
   if (entry.second) {
     // FIXME: Clear unnamed_addr if the global will be relative referenced
@@ -5978,9 +6078,6 @@ llvm::Constant *IRGenModule::getAddrOfGlobalString(StringRef data,
     (llvm::Twine(".nul") + llvm::Twine(i)).toVector(name);
   }
 
-  auto sectionName =
-    useOSLogSection ? "__TEXT,__oslogstring,cstring_literals" : "";
-
   entry = createStringConstant(data, willBeRelativelyAddressed,
                                sectionName, name);
   return entry.second;
@@ -5992,9 +6089,11 @@ IRGenModule::getAddrOfGlobalIdentifierString(StringRef data,
   if (Lexer::identifierMustAlwaysBeEscaped(data)) {
     llvm::SmallString<256> name;
     Mangle::Mangler::appendRawIdentifierForRuntime(data, name);
-    return getAddrOfGlobalString(name, willBeRelativelyAddressed);
+    return getAddrOfGlobalString(name, CStringSectionType::Default,
+                                 willBeRelativelyAddressed);
   }
-  return getAddrOfGlobalString(data, willBeRelativelyAddressed);
+  return getAddrOfGlobalString(data, CStringSectionType::Default,
+                               willBeRelativelyAddressed);
 }
 
 /// Get or create a global UTF-16 string constant.
@@ -6269,13 +6368,14 @@ IRGenModule::getAddrOfDefaultAssociatedConformanceAccessor(
 }
 
 llvm::Function *
-IRGenModule::getAddrOfContinuationPrototype(CanSILFunctionType fnType) {
+IRGenModule::getAddrOfContinuationPrototype(CanSILFunctionType fnType,
+                                            CanGenericSignature sig) {
   LinkEntity entity = LinkEntity::forCoroutineContinuationPrototype(fnType);
 
   llvm::Function *&entry = GlobalFuncs[entity];
   if (entry) return entry;
 
-  GenericContextScope scope(*this, fnType->getInvocationGenericSignature());
+  GenericContextScope scope(*this, sig);
   auto signature = Signature::forCoroutineContinuation(*this, fnType);
   LinkInfo link = LinkInfo::get(*this, entity, NotForDefinition);
   entry = createFunction(*this, link, signature);
diff --git a/lib/IRGen/GenDistributed.cpp b/lib/IRGen/GenDistributed.cpp
index 3a63725dc2897..12be410e34846 100644
--- a/lib/IRGen/GenDistributed.cpp
+++ b/lib/IRGen/GenDistributed.cpp
@@ -26,6 +26,7 @@
 #include "GenDecl.h"
 #include "GenMeta.h"
 #include "GenOpaque.h"
+#include "GenPointerAuth.h"
 #include "GenProto.h"
 #include "GenType.h"
 #include "IRGenDebugInfo.h"
@@ -51,11 +52,6 @@ using namespace irgen;
 
 llvm::Value *irgen::emitDistributedActorInitializeRemote(
     IRGenFunction &IGF, SILType selfType, llvm::Value *actorMetatype, Explosion &out) {
-  auto &classTI = IGF.getTypeInfo(selfType).as<ClassTypeInfo>();
-  auto &classLayout = classTI.getClassLayout(IGF.IGM, selfType,
-                                             /*forBackwardDeployment=*/false);
-  llvm::Type *destType = classLayout.getType()->getPointerTo();
-
   auto fn = IGF.IGM.getDistributedActorInitializeRemoteFunctionPointer();
   actorMetatype =
       IGF.Builder.CreateBitCast(actorMetatype, IGF.IGM.TypeMetadataPtrTy);
@@ -64,7 +60,7 @@ llvm::Value *irgen::emitDistributedActorInitializeRemote(
   call->setCallingConv(IGF.IGM.SwiftCC);
   call->setDoesNotThrow();
 
-  auto result = IGF.Builder.CreateBitCast(call, destType);
+  auto result = IGF.Builder.CreateBitCast(call, IGF.IGM.PtrTy);
 
   out.add(result);
 
@@ -82,7 +78,7 @@ getAccessorLinking(ThunkOrRequirement accessorFor) {
     return LinkEntity::forDistributedTargetAccessor(method);
   }
 
-  auto *requirement = accessorFor.get<AbstractFunctionDecl *>();
+  auto *requirement = cast<AbstractFunctionDecl *>(accessorFor);
   return LinkEntity::forDistributedTargetAccessor(requirement);
 }
 
@@ -156,7 +152,7 @@ struct AccessorTarget {
     if (auto *thunk = target.dyn_cast<SILFunction *>()) {
       Type = thunk->getLoweredFunctionType();
     } else {
-      auto *requirement = target.get<AbstractFunctionDecl *>();
+      auto *requirement = cast<AbstractFunctionDecl *>(target);
       Type = IGF.IGM.getSILTypes().getConstantFunctionType(
           IGF.IGM.getMaximalTypeExpansionContext(),
           SILDeclRef(requirement).asDistributed());
@@ -166,7 +162,7 @@ struct AccessorTarget {
   DeclContext *getDeclContext() const {
     if (auto *thunk = Target.dyn_cast<SILFunction *>())
       return thunk->getDeclContext();
-    return Target.get<AbstractFunctionDecl *>();
+    return cast<AbstractFunctionDecl *>(Target);
   }
 
   CanSILFunctionType getType() const { return Type; }
@@ -277,8 +273,7 @@ static CanSILFunctionType getAccessorType(IRGenModule &IGM) {
   SmallVector<GenericFunctionType::Param, 8> parameters;
 
   // A generic parameter that represents instance of invocation decoder.
-  auto *decoderType =
-      GenericTypeParamType::getType(/*depth=*/ 0, /*index=*/ 0, Context);
+  auto decoderType = Context.TheSelfType;
 
   // decoder
   parameters.push_back(GenericFunctionType::Param(
@@ -589,9 +584,26 @@ static llvm::Value *lookupWitnessTable(IRGenFunction &IGF, llvm::Value *witness,
   assert(Lowering::TypeConverter::protocolRequiresWitnessTable(protocol));
 
   auto &IGM = IGF.IGM;
-  auto *protocolDescriptor = IGM.getAddrOfProtocolDescriptor(protocol);
+  llvm::Value *protocolDescriptor = IGM.getAddrOfProtocolDescriptor(protocol);
+
+  bool signedProtocolDescriptor = IGM.getAvailabilityRange().isContainedIn(
+    IGM.Context.getSignedConformsToProtocolAvailability());
+
+  auto conformsToProtocolFunctionPointer = signedProtocolDescriptor ?
+    IGM.getConformsToProtocol2FunctionPointer() :
+    IGM.getConformsToProtocolFunctionPointer();
+
+  // Sign the protocol descriptor.
+  auto schema = IGF.IGM.getOptions().PointerAuth.ProtocolDescriptorsAsArguments;
+  if (schema && signedProtocolDescriptor) {
+    auto authInfo = PointerAuthInfo::emit(
+        IGF, schema, nullptr,
+        PointerAuthEntity::Special::ProtocolDescriptorAsArgument);
+    protocolDescriptor = emitPointerAuthSign(IGF, protocolDescriptor, authInfo);
+  }
+
   auto *witnessTable = IGF.Builder.CreateCall(
-      IGM.getConformsToProtocolFunctionPointer(), {witness, protocolDescriptor});
+      conformsToProtocolFunctionPointer, {witness, protocolDescriptor});
 
   auto failBB = IGF.createBasicBlock("missing-witness");
   auto contBB = IGF.createBasicBlock("");
@@ -648,8 +660,7 @@ void DistributedAccessor::emitLoadOfWitnessTables(llvm::Value *witnessTables,
 
   IGF.Builder.emitBlock(contBB);
 
-  witnessTables = IGF.Builder.CreateBitCast(witnessTables,
-                                            IGM.Int8PtrPtrTy->getPointerTo());
+  witnessTables = IGF.Builder.CreateBitCast(witnessTables, IGM.PtrTy);
 
   for (unsigned i = 0, n = expectedWitnessTables; i != n; ++i) {
     auto offset = Size(i * IGM.getPointerSize());
@@ -741,8 +752,7 @@ void DistributedAccessor::emit() {
     emitAsyncFunctionPointer(IGM, IGF.CurFn, entity, AsyncLayout.getSize());
   }
 
-  auto *typedResultBuffer = IGF.Builder.CreateBitCast(
-    resultBuffer, IGM.getStoragePointerType(directResultTy));
+  auto *typedResultBuffer = IGF.Builder.CreateBitCast(resultBuffer, IGM.PtrTy);
 
   if (targetConv.getNumIndirectSILResults()) {
     // Since tuples are not allowed as valid result types (because they cannot
@@ -849,16 +859,15 @@ FunctionPointer AccessorTarget::getPointerToTarget(llvm::Value *actorSelf) {
     auto fpKind = classifyFunctionPointerKind(thunk);
     auto signature = IGM.getSignature(Type, fpKind);
 
-    auto *fnPtr =
-        llvm::ConstantExpr::getBitCast(IGM.getAddrOfAsyncFunctionPointer(thunk),
-                                       signature.getType()->getPointerTo());
+    auto *fnPtr = llvm::ConstantExpr::getBitCast(
+        IGM.getAddrOfAsyncFunctionPointer(thunk), IGM.PtrTy);
 
     return FunctionPointer::forDirect(
         FunctionPointer::Kind(Type), fnPtr,
         IGM.getAddrOfSILFunction(thunk, NotForDefinition), signature);
   }
 
-  auto *requirementDecl = Target.get<AbstractFunctionDecl *>();
+  auto *requirementDecl = cast<AbstractFunctionDecl *>(Target);
   auto *protocol = requirementDecl->getDeclContext()->getSelfProtocolDecl();
   SILDeclRef requirementRef = SILDeclRef(requirementDecl).asDistributed();
 
@@ -893,13 +902,13 @@ Callee AccessorTarget::getCallee(llvm::Value *actorSelf) {
 }
 
 WitnessMetadata *AccessorTarget::getWitnessMetadata(llvm::Value *actorSelf) {
-  if (Target.is<SILFunction *>())
+  if (isa<SILFunction *>(Target))
     return nullptr;
 
   if (!Witness) {
     WitnessMetadata witness;
 
-    auto *requirement = Target.get<AbstractFunctionDecl *>();
+    auto *requirement = cast<AbstractFunctionDecl *>(Target);
     auto *protocol = requirement->getDeclContext()->getSelfProtocolDecl();
     assert(protocol);
 
@@ -966,11 +975,9 @@ ArgumentDecoderInfo DistributedAccessor::findArgumentDecoder(
         IGM.getSILModule(), methodTy, expansionContext);
 
     auto &classTI = IGM.getTypeInfo(selfTy).as<ClassTypeInfo>();
-    auto &classLayout = classTI.getClassLayout(IGM, selfTy,
-                                               /*forBackwardDeployment=*/false);
 
-    llvm::Value *typedDecoderPtr = IGF.Builder.CreateBitCast(
-        decoder, classLayout.getType()->getPointerTo()->getPointerTo());
+    llvm::Value *typedDecoderPtr =
+        IGF.Builder.CreateBitCast(decoder, IGM.PtrTy);
 
     Explosion instance;
 
diff --git a/lib/IRGen/GenEnum.cpp b/lib/IRGen/GenEnum.cpp
index 6ebefa3652113..8b60df5ae7c07 100644
--- a/lib/IRGen/GenEnum.cpp
+++ b/lib/IRGen/GenEnum.cpp
@@ -330,7 +330,7 @@ EnumImplStrategy::emitOutlinedGetEnumTag(IRGenFunction &IGF, SILType T,
                                                      manglingBits.second);
 
     const TypeInfo &ti = IGF.getTypeInfo(T);
-    auto ptrTy = ti.getStorageType()->getPointerTo();
+    auto *ptrTy = IGF.IGM.PtrTy;
     llvm::SmallVector<llvm::Type *, 4> paramTys;
     paramTys.push_back(ptrTy);
 
@@ -736,8 +736,8 @@ namespace {
 
       // Pre swift-5.1 runtimes were missing the initialization of the
       // the extraInhabitantCount field. Do it here instead.
-      auto payloadRef = IGF.Builder.CreateBitOrPointerCast(
-          payloadLayout, IGF.IGM.TypeLayoutTy->getPointerTo());
+      auto payloadRef =
+          IGF.Builder.CreateBitOrPointerCast(payloadLayout, IGM.PtrTy);
       auto payloadExtraInhabitantCount =
           IGF.Builder.CreateLoad(IGF.Builder.CreateStructGEP(
               Address(payloadRef, IGF.IGM.TypeLayoutTy, Alignment(1)), 3,
@@ -774,8 +774,8 @@ namespace {
       // Pre swift-5.1 runtimes were missing the initialization of the
       // the extraInhabitantCount field. Do it here instead.
       auto payloadLayout = emitTypeLayoutRef(IGF, payloadTy, collector);
-      auto payloadRef = IGF.Builder.CreateBitOrPointerCast(
-          payloadLayout, IGF.IGM.TypeLayoutTy->getPointerTo());
+      auto payloadRef =
+          IGF.Builder.CreateBitOrPointerCast(payloadLayout, IGM.PtrTy);
       auto payloadExtraInhabitantCount =
           IGF.Builder.CreateLoad(IGF.Builder.CreateStructGEP(
               Address(payloadRef, IGF.IGM.TypeLayoutTy, Alignment(1)), 3,
@@ -1430,10 +1430,7 @@ namespace {
   // types other than i1 or power-of-two-byte sizes like i8, i16, etc. inhibit
   // FastISel and expose backend bugs.
   static unsigned getIntegerBitSizeForTag(unsigned tagBits) {
-    // i1 is used to represent bool in C so is fairly well supported.
-    if (tagBits == 1)
-      return 1;
-    // Otherwise, round the physical size in bytes up to the next power of two.
+    // Round the physical size in bytes up to the next power of two.
     unsigned tagBytes = (tagBits + 7U)/8U;
     if (!llvm::isPowerOf2_32(tagBytes))
       tagBytes = llvm::NextPowerOf2(tagBytes);
@@ -2074,8 +2071,7 @@ namespace {
       auto PayloadT = getPayloadType(IGF.IGM, T);
 
       auto &fixedTI = getFixedPayloadTypeInfo();
-      auto addr = IGF.Builder.CreateBitCast(
-          enumAddr.getAddress(), fixedTI.getStorageType()->getPointerTo());
+      auto addr = IGF.Builder.CreateBitCast(enumAddr.getAddress(), IGM.PtrTy);
       return fixedTI.getEnumTagSinglePayload(IGF, numEmptyCases,
                                              fixedTI.getAddressForPointer(addr),
                                              PayloadT, /*isOutlined*/ false);
@@ -2221,15 +2217,9 @@ namespace {
       // If any tag bits are present, they must match.
       llvm::Value *tagResult = nullptr;
       if (tagBits) {
-        if (ExtraTagBitCount == 1) {
-          if (extraTag == 1)
-            tagResult = tagBits;
-          else
-            tagResult = IGF.Builder.CreateNot(tagBits);
-        } else {
-          tagResult = IGF.Builder.CreateICmpEQ(tagBits,
-                    llvm::ConstantInt::get(IGF.IGM.getLLVMContext(), extraTag));
-        }
+        tagResult = IGF.Builder.CreateICmpEQ(
+            tagBits,
+            llvm::ConstantInt::get(IGF.IGM.getLLVMContext(), extraTag));
       }
       
       if (tagResult && payloadResult)
@@ -2311,7 +2301,9 @@ namespace {
             oneDest = llvm::BasicBlock::Create(C);
             tagBitBlocks.push_back(oneDest);
           }
-          IGF.Builder.CreateCondBr(tagBits, oneDest, zeroDest);
+          auto isOne = IGF.Builder.CreateICmpEQ(
+              tagBits, llvm::ConstantInt::get(tagBits->getType(), 1));
+          IGF.Builder.CreateCondBr(isOne, oneDest, zeroDest);
         } else {
           auto swi = SwitchBuilder::create(IGF, tagBits,
                            SwitchDefaultDest(unreachableBB, IsUnreachable),
@@ -2587,14 +2579,9 @@ namespace {
       // If we have extra tag bits, they will be zero if we contain a payload.
       if (ExtraTagBitCount > 0) {
         assert(extraBits);
-        llvm::Value *isNonzero;
-        if (ExtraTagBitCount == 1) {
-          isNonzero = extraBits;
-        } else {
-          llvm::Value *zero = llvm::ConstantInt::get(extraBits->getType(), 0);
-          isNonzero = IGF.Builder.CreateICmp(llvm::CmpInst::ICMP_NE,
-                                         extraBits, zero);
-        }
+        llvm::Value *zero = llvm::ConstantInt::get(extraBits->getType(), 0);
+        llvm::Value *isNonzero =
+            IGF.Builder.CreateICmp(llvm::CmpInst::ICMP_NE, extraBits, zero);
 
         auto *zeroBB = llvm::BasicBlock::Create(IGF.IGM.getLLVMContext());
         IGF.Builder.CreateCondBr(isNonzero, nonzeroBB, zeroBB);
@@ -6549,8 +6536,9 @@ EnumImplStrategy::get(TypeConverter &TC, SILType type, EnumDecl *theEnum) {
         std::move(elementsWithPayload), std::move(elementsWithNoPayload)));
   }
 
-  // Enums imported from Clang or marked with @objc use C-compatible layout.
-  if (theEnum->hasClangNode() || theEnum->isObjC()) {
+  // Enums imported from Clang or marked with @objc or @c use a
+  // C-compatible layout.
+  if (theEnum->hasClangNode() || theEnum->isCCompatibleEnum()) {
     assert(elementsWithPayload.empty() && "C enum with payload?!");
     assert(alwaysFixedSize == IsFixedSize && "C enum with resilient payload?!");
     return std::unique_ptr<EnumImplStrategy>(
@@ -6995,7 +6983,7 @@ CCompatibleEnumImplStrategy::completeEnumTypeLayout(TypeConverter &TC,
                                                     llvm::StructType *enumTy){
   // The type should have come from Clang or be @objc,
   // and should have a raw type.
-  assert((theEnum->hasClangNode() || theEnum->isObjC())
+  assert((theEnum->hasClangNode() || theEnum->isCCompatibleEnum())
          && "c-compatible enum didn't come from clang!");
   assert(theEnum->hasRawType()
          && "c-compatible enum doesn't have raw type!");
@@ -7567,9 +7555,8 @@ llvm::Constant *IRGenModule::getOrCreateOutlinedDestructiveProjectDataForLoad(
                                                          manglingBits.second,
                                                          caseIdx);
 
-  auto ptrTy = ti.getStorageType()->getPointerTo();
   llvm::SmallVector<llvm::Type *, 4> paramTys;
-  paramTys.push_back(ptrTy);
+  paramTys.push_back(PtrTy);
 
   return getOrCreateHelperFunction(funcName, PtrTy, paramTys,
       [&](IRGenFunction &IGF) {
@@ -7642,9 +7629,8 @@ llvm::Constant *IRGenModule::getOrCreateOutlinedEnumTagStoreFunction(
                                                              manglingBits.second,
                                                              caseIdx);
 
-  auto ptrTy = ti.getStorageType()->getPointerTo();
   llvm::SmallVector<llvm::Type *, 4> paramTys;
-  paramTys.push_back(ptrTy);
+  paramTys.push_back(PtrTy);
 
   return getOrCreateHelperFunction(funcName, VoidTy, paramTys,
       [&](IRGenFunction &IGF) {
diff --git a/lib/IRGen/GenExistential.cpp b/lib/IRGen/GenExistential.cpp
index b1333fd611d89..1c39124ce0e60 100644
--- a/lib/IRGen/GenExistential.cpp
+++ b/lib/IRGen/GenExistential.cpp
@@ -130,6 +130,7 @@ namespace {
   class ExistentialTypeInfoBase : public Base,
       private llvm::TrailingObjects<Derived, const ProtocolDecl *> {
     friend class llvm::TrailingObjects<Derived, const ProtocolDecl *>;
+    using Tail = llvm::TrailingObjects<Derived, const ProtocolDecl *>;
 
     /// The number of non-trivial protocols for this existential.
     unsigned NumStoredProtocols;
@@ -148,7 +149,7 @@ namespace {
         : Base(std::forward<As>(args)...),
           NumStoredProtocols(protocols.size()) {
       std::uninitialized_copy(protocols.begin(), protocols.end(),
-          this->template getTrailingObjects<const ProtocolDecl *>());
+                              this->getTrailingObjects());
     }
 
   public:
@@ -157,12 +158,19 @@ namespace {
     create(ArrayRef<const ProtocolDecl *> protocols, As &&...args)
     {
       void *buffer = operator new(
-          llvm::TrailingObjects<Derived, const ProtocolDecl *>::
-              template totalSizeToAlloc<const ProtocolDecl *>(
-                  protocols.size()));
+          Tail::template totalSizeToAlloc<const ProtocolDecl *>(
+              protocols.size()));
       return new (buffer) Derived(protocols, std::forward<As>(args)...);
     }
 
+    void operator delete(void *ptr) {
+      const auto *pThis = static_cast<ExistentialTypeInfoBase *>(ptr);
+      const size_t count = pThis->NumStoredProtocols;
+      const size_t size =
+          Tail::template totalSizeToAlloc<const ProtocolDecl *>(count);
+      ::operator delete(ptr, size);
+    }
+
     /// Returns the number of protocol witness tables directly carried
     /// by values of this type.
     unsigned getNumStoredProtocols() const { return NumStoredProtocols; }
@@ -172,8 +180,7 @@ namespace {
     /// type are not know to implement any protocols, although we do
     /// still know how to manipulate them.
     ArrayRef<const ProtocolDecl *> getStoredProtocols() const {
-      return {this->template getTrailingObjects<const ProtocolDecl *>(),
-              NumStoredProtocols};
+      return this->getTrailingObjects(NumStoredProtocols);
     }
 
     /// Given the address of an existential object, find the witness
@@ -939,7 +946,7 @@ class OpaqueExistentialTypeInfo final :
     // Use copy-on-write existentials?
     auto fn = getAssignBoxedOpaqueExistentialBufferFunction(
         IGF.IGM, getLayout());
-    auto *type = IGF.IGM.getExistentialPtrTy(getLayout().getNumTables());
+    auto *type = IGF.IGM.PtrTy;
     auto *destAddr = IGF.Builder.CreateBitCast(dest.getAddress(), type);
     auto *srcAddr = IGF.Builder.CreateBitCast(src.getAddress(), type);
     auto call = IGF.Builder.CreateCallWithoutDbgLoc(fn->getFunctionType(), fn,
@@ -1006,9 +1013,7 @@ class OpaqueExistentialTypeInfo final :
     // Use copy-on-write existentials?
     auto fn = getDestroyBoxedOpaqueExistentialBufferFunction(
         IGF.IGM, getLayout());
-    auto *addr = IGF.Builder.CreateBitCast(
-        buffer.getAddress(),
-        IGF.IGM.getExistentialPtrTy(getLayout().getNumTables()));
+    auto *addr = IGF.Builder.CreateBitCast(buffer.getAddress(), IGF.IGM.PtrTy);
     auto call =
         IGF.Builder.CreateCallWithoutDbgLoc(fn->getFunctionType(), fn, {addr});
     call->setCallingConv(IGF.IGM.DefaultCC);
@@ -1538,10 +1543,6 @@ llvm::Type *TypeConverter::getExistentialType(unsigned numWitnessTables) {
   return type;
 }
 
-llvm::PointerType *IRGenModule::getExistentialPtrTy(unsigned numTables) {
-  return Types.getExistentialType(numTables)->getPointerTo();
-}
-
 llvm::Type *IRGenModule::getExistentialType(unsigned numTables) {
   return Types.getExistentialType(numTables);
 }
@@ -1834,8 +1835,7 @@ ContainedAddress irgen::emitBoxedExistentialProjection(IRGenFunction &IGF,
   auto &projectedTI = IGF.getTypeInfoForLowered(projectedType);
   auto projectedPtrAddr = IGF.Builder.CreateStructGEP(out, 0, Size(0));
   llvm::Value *projectedPtr = IGF.Builder.CreateLoad(projectedPtrAddr);
-  projectedPtr = IGF.Builder.CreateBitCast(projectedPtr,
-                               projectedTI.getStorageType()->getPointerTo());
+  projectedPtr = IGF.Builder.CreateBitCast(projectedPtr, IGF.IGM.PtrTy);
   auto projected = projectedTI.getAddressForPointer(projectedPtr);
   return ContainedAddress(out, projected);
 }
@@ -1898,8 +1898,7 @@ OwnedAddress irgen::emitBoxedExistentialContainerAllocation(IRGenFunction &IGF,
       ExistentialArchetypeType::get(destType.getASTType());
   auto &srcTI = IGF.getTypeInfoForUnlowered(AbstractionPattern(archetype),
                                             formalSrcType);
-  addr = IGF.Builder.CreateBitCast(addr,
-                                   srcTI.getStorageType()->getPointerTo());
+  addr = IGF.Builder.CreateBitCast(addr, IGF.IGM.PtrTy);
   return OwnedAddress(srcTI.getAddressForPointer(addr), box);
 }
 
@@ -2047,9 +2046,7 @@ void irgen::emitMetatypeOfOpaqueExistential(IRGenFunction &IGF, Address buffer,
   // Project the buffer and apply the 'typeof' value witness.
   llvm::Value *object;
 
-  auto *addr = IGF.Builder.CreateBitCast(
-      buffer.getAddress(),
-      IGF.IGM.getExistentialPtrTy(existLayout.getNumTables()));
+  auto *addr = IGF.Builder.CreateBitCast(buffer.getAddress(), IGF.IGM.PtrTy);
   auto *projectFunc = getProjectBoxedOpaqueExistentialFunction(
       IGF, OpenedExistentialAccess::Immutable, existLayout);
   auto *addrOfValue = IGF.Builder.CreateCallWithoutDbgLoc(
@@ -2243,7 +2240,7 @@ static Address castToOpaquePtr(IRGenFunction &IGF, Address addr) {
 static llvm::Function *getAllocateBoxedOpaqueExistentialBufferFunction(
     IRGenModule &IGM, OpaqueExistentialLayout existLayout) {
 
-  llvm::Type *argTys[] = {IGM.getExistentialPtrTy(existLayout.getNumTables())};
+  llvm::Type *argTys[] = {IGM.PtrTy};
 
   // __swift_allocate_boxed_opaque_existential__N is the well-known function for
   // allocating buffers in existential containers of types with N witness
@@ -2286,11 +2283,10 @@ static llvm::Function *getAllocateBoxedOpaqueExistentialBufferFunction(
           addressInBox =
               IGF.Builder.CreateBitCast(address, IGF.IGM.OpaquePtrTy);
           IGF.Builder.CreateStore(
-              box,
-              Address(IGF.Builder.CreateBitCast(existentialBuffer.getAddress(),
-                                                box->getType()->getPointerTo()),
-                      IGF.IGM.RefCountedPtrTy,
-                      existLayout.getAlignment(IGF.IGM)));
+              box, Address(IGF.Builder.CreateBitCast(
+                               existentialBuffer.getAddress(), IGM.PtrTy),
+                           IGF.IGM.RefCountedPtrTy,
+                           existLayout.getAlignment(IGF.IGM)));
           IGF.Builder.CreateRet(addressInBox);
         }
       },
@@ -2310,7 +2306,6 @@ Address irgen::emitAllocateBoxedOpaqueExistentialBuffer(
       existLayout.projectExistentialBuffer(IGF, existentialContainer);
 
   auto &valueTI = IGF.getTypeInfo(valueType);
-  auto *valuePointerType = valueTI.getStorageType()->getPointerTo();
 
   // Check if the value is fixed size.
   if (auto *fixedTI = dyn_cast<FixedTypeInfo>(&valueTI)) {
@@ -2318,7 +2313,7 @@ Address irgen::emitAllocateBoxedOpaqueExistentialBuffer(
     // sufficient.
     if (fixedTI->getFixedPacking(IGF.IGM) == FixedPacking::OffsetZero) {
       return valueTI.getAddressForPointer(IGF.Builder.CreateBitCast(
-          existentialBuffer.getAddress(), valuePointerType));
+          existentialBuffer.getAddress(), IGF.IGM.PtrTy));
     }
     // Otherwise, allocate a box with enough storage.
     Address addr = emitAllocateExistentialBoxInBuffer(
@@ -2330,20 +2325,19 @@ Address irgen::emitAllocateBoxedOpaqueExistentialBuffer(
   auto *allocateFun = getAllocateBoxedOpaqueExistentialBufferFunction(
       IGF.IGM, existLayout);
   auto *existentialAddr = IGF.Builder.CreateBitCast(
-      existentialContainer.getAddress(),
-      IGF.IGM.getExistentialPtrTy(existLayout.getNumTables()));
+      existentialContainer.getAddress(), IGF.IGM.PtrTy);
   auto *call = IGF.Builder.CreateCallWithoutDbgLoc(
       allocateFun->getFunctionType(), allocateFun, {existentialAddr});
   call->setCallingConv(IGF.IGM.DefaultCC);
   call->setDoesNotThrow();
-  auto addressOfValue = IGF.Builder.CreateBitCast(call, valuePointerType);
+  auto addressOfValue = IGF.Builder.CreateBitCast(call, IGF.IGM.PtrTy);
   return valueTI.getAddressForPointer(addressOfValue);
 }
 
 static llvm::Function *getDeallocateBoxedOpaqueExistentialBufferFunction(
     IRGenModule &IGM, OpaqueExistentialLayout existLayout) {
 
-  llvm::Type *argTys[] = {IGM.getExistentialPtrTy(existLayout.getNumTables())};
+  llvm::Type *argTys[] = {IGM.PtrTy};
 
   // __swift_deallocate_boxed_opaque_existential_N is the well-known function
   // for deallocating buffers in existential containers of types with N witness
@@ -2384,8 +2378,7 @@ static llvm::Function *getDeallocateBoxedOpaqueExistentialBufferFunction(
         auto existentialBuffer =
             existLayout.projectExistentialBuffer(IGF, existentialContainer);
         auto *boxReferenceAddr =
-            Builder.CreateBitCast(existentialBuffer.getAddress(),
-                                  IGM.RefCountedPtrTy->getPointerTo());
+            Builder.CreateBitCast(existentialBuffer.getAddress(), IGM.PtrTy);
         // Load the reference.
         auto *boxReference =
             Builder.CreateLoad(Address(boxReferenceAddr, IGM.RefCountedPtrTy,
@@ -2427,8 +2420,7 @@ void irgen::emitDeallocateBoxedOpaqueExistentialBuffer(
   auto *deallocateFun = getDeallocateBoxedOpaqueExistentialBufferFunction(
       IGF.IGM, existLayout);
   auto *bufferAddr = IGF.Builder.CreateBitCast(
-      existentialContainer.getAddress(),
-      IGF.IGM.getExistentialPtrTy(existLayout.getNumTables()));
+      existentialContainer.getAddress(), IGF.IGM.PtrTy);
   auto *call = IGF.Builder.CreateCallWithoutDbgLoc(
       deallocateFun->getFunctionType(), deallocateFun, {bufferAddr});
   call->setCallingConv(IGF.IGM.DefaultCC);
@@ -2447,8 +2439,7 @@ void irgen::emitDestroyBoxedOpaqueExistentialBuffer(
   auto *deallocateFun =
       getDestroyBoxedOpaqueExistentialBufferFunction(IGF.IGM, existLayout);
   auto *bufferAddr = IGF.Builder.CreateBitCast(
-      existentialContainer.getAddress(),
-      IGF.IGM.getExistentialPtrTy(existLayout.getNumTables()));
+      existentialContainer.getAddress(), IGF.IGM.PtrTy);
   auto *call = IGF.Builder.CreateCallWithoutDbgLoc(
     deallocateFun->getFunctionType(), deallocateFun, {bufferAddr});
   call->setCallingConv(IGF.IGM.DefaultCC);
@@ -2462,7 +2453,7 @@ getProjectBoxedOpaqueExistentialFunction(IRGenFunction &IGF,
                                          OpaqueExistentialLayout existLayout) {
 
   auto &IGM = IGF.IGM;
-  auto *existentialBufferTy = IGM.getExistentialPtrTy(existLayout.getNumTables());
+  auto *existentialBufferTy = IGF.IGM.PtrTy;
   llvm::Type *argTys[] = {existentialBufferTy, IGM.TypeMetadataPtrTy};
 
   // __swift_project_boxed_opaque_existential_N is the well-known function for
@@ -2506,8 +2497,7 @@ getProjectBoxedOpaqueExistentialFunction(IRGenFunction &IGF,
         if (accessKind == OpenedExistentialAccess::Immutable) {
           // Project to the existential buffer address.
           auto *boxReferenceAddr =
-              Builder.CreateBitCast(existentialBuffer.getAddress(),
-                                    IGM.RefCountedPtrTy->getPointerTo());
+              Builder.CreateBitCast(existentialBuffer.getAddress(), IGM.PtrTy);
           // Load the reference.
           auto *boxReference =
               Builder.CreateLoad(Address(boxReferenceAddr, IGM.RefCountedPtrTy,
@@ -2522,8 +2512,7 @@ getProjectBoxedOpaqueExistentialFunction(IRGenFunction &IGF,
           auto *Add = Builder.CreateAdd(heapHeaderSize, alignmentMask);
           auto *Not = Builder.CreateNot(alignmentMask);
           auto *startOffset = Builder.CreateAnd(Add, Not);
-          auto *addressInBox =
-              IGF.emitByteOffsetGEP(boxReference, startOffset, IGM.OpaqueTy);
+          auto *addressInBox = IGF.emitByteOffsetGEP(boxReference, startOffset);
           IGF.Builder.CreateRet(addressInBox);
           return;
         }
@@ -2592,9 +2581,8 @@ Address irgen::emitOpaqueBoxedExistentialProjection(
 
   auto *projectFunc =
       getProjectBoxedOpaqueExistentialFunction(IGF, accessKind, layout);
-  auto *bufferAddr = IGF.Builder.CreateBitCast(
-      base.getAddress(),
-      IGF.IGM.getExistentialPtrTy(layout.getNumTables()));
+  auto *bufferAddr =
+      IGF.Builder.CreateBitCast(base.getAddress(), IGF.IGM.PtrTy);
   auto *addrOfValue = IGF.Builder.CreateCallWithoutDbgLoc(
       projectFunc->getFunctionType(), projectFunc, {bufferAddr, metadata});
   addrOfValue->setCallingConv(IGF.IGM.DefaultCC);
@@ -2610,23 +2598,22 @@ static void initBufferWithCopyOfReference(IRGenFunction &IGF,
   auto &IGM = IGF.IGM;
   auto &Builder = IGF.Builder;
 
-  auto *destReferenceAddr = Builder.CreateBitCast(
-      destBuffer.getAddress(), IGM.RefCountedPtrTy->getPointerTo());
-  auto *srcReferenceAddr = Builder.CreateBitCast(
-      srcBuffer.getAddress(), IGM.RefCountedPtrTy->getPointerTo());
+  auto *destReferenceAddr =
+      Builder.CreateBitCast(destBuffer.getAddress(), IGM.PtrTy);
+  auto *srcReferenceAddr =
+      Builder.CreateBitCast(srcBuffer.getAddress(), IGM.PtrTy);
   auto *srcReference = Builder.CreateLoad(
-      Address(srcReferenceAddr, IGM.RefCountedPtrTy, srcBuffer.getAlignment()));
+      Address(srcReferenceAddr, IGM.PtrTy, srcBuffer.getAlignment()));
   IGF.emitNativeStrongRetain(srcReference, IGF.getDefaultAtomicity());
-  IGF.Builder.CreateStore(srcReference,
-                          Address(destReferenceAddr, IGM.RefCountedPtrTy,
-                                  existLayout.getAlignment(IGF.IGM)));
+  IGF.Builder.CreateStore(
+      srcReference,
+      Address(destReferenceAddr, IGM.PtrTy, existLayout.getAlignment(IGF.IGM)));
 }
 
 static llvm::Function *getAssignBoxedOpaqueExistentialBufferFunction(
     IRGenModule &IGM, OpaqueExistentialLayout existLayout) {
 
-  llvm::Type *argTys[] = {IGM.getExistentialPtrTy(existLayout.getNumTables()),
-                          IGM.getExistentialPtrTy(existLayout.getNumTables())};
+  llvm::Type *argTys[] = {IGM.PtrTy, IGM.PtrTy};
 
   // __swift_assign_box_in_existentials_N is the well-known function for
   // assigning buffers in existential containers of types with N witness
@@ -2695,10 +2682,10 @@ static llvm::Function *getAssignBoxedOpaqueExistentialBufferFunction(
           Builder.emitBlock(matchOutlineBB);
           {
             ConditionalDominanceScope outlineCondition(IGF);
-            auto *destReferenceAddr = Builder.CreateBitCast(
-                destBuffer.getAddress(), IGM.RefCountedPtrTy->getPointerTo());
-            auto *srcReferenceAddr = Builder.CreateBitCast(
-                srcBuffer.getAddress(), IGM.RefCountedPtrTy->getPointerTo());
+            auto *destReferenceAddr =
+                Builder.CreateBitCast(destBuffer.getAddress(), IGM.PtrTy);
+            auto *srcReferenceAddr =
+                Builder.CreateBitCast(srcBuffer.getAddress(), IGM.PtrTy);
             // Load the reference.
             auto *destReference = Builder.CreateLoad(
                 Address(destReferenceAddr, IGM.RefCountedPtrTy,
@@ -2798,8 +2785,8 @@ static llvm::Function *getAssignBoxedOpaqueExistentialBufferFunction(
           {
             ConditionalDominanceScope destOutlineCondition(IGF);
             // tmpRef = dest[0]
-            auto *destReferenceAddr = Builder.CreateBitCast(
-                destBuffer.getAddress(), IGM.RefCountedPtrTy->getPointerTo());
+            auto *destReferenceAddr =
+                Builder.CreateBitCast(destBuffer.getAddress(), IGM.PtrTy);
             auto *destReference = Builder.CreateLoad(
                 Address(destReferenceAddr, IGM.RefCountedPtrTy,
                         srcBuffer.getAlignment()));
@@ -2850,7 +2837,7 @@ static llvm::Function *getAssignBoxedOpaqueExistentialBufferFunction(
 static llvm::Function *getDestroyBoxedOpaqueExistentialBufferFunction(
     IRGenModule &IGM, OpaqueExistentialLayout existLayout) {
 
-  llvm::Type *argTys[] = {IGM.getExistentialPtrTy(existLayout.getNumTables())};
+  llvm::Type *argTys[] = {IGM.PtrTy};
 
   llvm::SmallString<40> fnName;
   llvm::raw_svector_ostream(fnName)
@@ -2892,8 +2879,8 @@ static llvm::Function *getDestroyBoxedOpaqueExistentialBufferFunction(
           ConditionalDominanceScope domScope(IGF);
 
           // swift_release(buffer[0])
-          auto *referenceAddr = Builder.CreateBitCast(
-              buffer.getAddress(), IGM.RefCountedPtrTy->getPointerTo());
+          auto *referenceAddr =
+              Builder.CreateBitCast(buffer.getAddress(), IGM.PtrTy);
           auto *reference = Builder.CreateLoad(Address(
               referenceAddr, IGM.RefCountedPtrTy, buffer.getAlignment()));
           IGF.emitNativeStrongRelease(reference, IGF.getDefaultAtomicity());
diff --git a/lib/IRGen/GenFunc.cpp b/lib/IRGen/GenFunc.cpp
index eb210042d75ab..0660d8df54abc 100644
--- a/lib/IRGen/GenFunc.cpp
+++ b/lib/IRGen/GenFunc.cpp
@@ -78,8 +78,10 @@
 #include "swift/AST/SubstitutionMap.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/ClangImporter/ClangImporter.h"
 #include "swift/IRGen/Linking.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/Basic/CodeGenOptions.h"
 #include "clang/CodeGen/CodeGenABITypes.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/IR/Constants.h"
@@ -801,9 +803,7 @@ static void emitApplyArgument(IRGenFunction &IGF,
     
     // If a substitution is in play, just bitcast the address.
     if (isSubstituted) {
-      auto origType = IGF.IGM.getStoragePointerType(
-          silConv.getSILType(origParam, origFnTy, context));
-      addr = IGF.Builder.CreateBitCast(addr, origType);
+      addr = IGF.Builder.CreateBitCast(addr, IGF.IGM.PtrTy);
     }
     
     out.add(addr);
@@ -862,6 +862,45 @@ CanType irgen::getArgumentLoweringType(CanType type, SILParameterInfo paramInfo,
   llvm_unreachable("unhandled convention");
 }
 
+llvm::Constant *irgen::getCoroFrameAllocStubFn(IRGenModule &IGM) {
+  // If the coroutine allocation function is always available, call it directly.
+  auto coroAllocPtr = IGM.getCoroFrameAllocFn();
+  auto coroAllocFn = dyn_cast<llvm::Function>(coroAllocPtr);
+  if (coroAllocFn->getLinkage() != llvm::GlobalValue::ExternalWeakLinkage)
+    return coroAllocFn;
+
+  // Otherwise, create a stub function to call it when available, or malloc
+  // when it isn't.
+  return IGM.getOrCreateHelperFunction(
+    "__swift_coroFrameAllocStub", IGM.Int8PtrTy,
+    {IGM.SizeTy, IGM.Int64Ty},
+    [&](IRGenFunction &IGF) {
+      auto parameters = IGF.collectParameters();
+      auto *size = parameters.claimNext();
+      auto *coroFrameAllocFn = IGF.IGM.getOpaquePtr(coroAllocPtr);
+      auto *nullSwiftCoroFrameAlloc = IGF.Builder.CreateCmp(
+        llvm::CmpInst::Predicate::ICMP_NE, coroFrameAllocFn,
+        llvm::ConstantPointerNull::get(
+            cast<llvm::PointerType>(coroFrameAllocFn->getType())));
+      auto *coroFrameAllocReturn = IGF.createBasicBlock("return-coroFrameAlloc");
+      auto *mallocReturn = IGF.createBasicBlock("return-malloc");
+      IGF.Builder.CreateCondBr(nullSwiftCoroFrameAlloc, coroFrameAllocReturn, mallocReturn);
+
+      IGF.Builder.emitBlock(coroFrameAllocReturn);
+      auto *mallocTypeId = parameters.claimNext();
+      auto *coroFrameAllocCall = IGF.Builder.CreateCall(IGF.IGM.getCoroFrameAllocFunctionPointer(), {size, mallocTypeId});
+      IGF.Builder.CreateRet(coroFrameAllocCall);
+
+      IGF.Builder.emitBlock(mallocReturn);
+      auto *mallocCall = IGF.Builder.CreateCall(IGF.IGM.getMallocFunctionPointer(), {size});
+      IGF.Builder.CreateRet(mallocCall);
+    },
+    /*setIsNoInline=*/false,
+    /*forPrologue=*/false,
+    /*isPerformanceConstraint=*/false,
+    /*optionalLinkageOverride=*/nullptr, llvm::CallingConv::C);
+}
+
 static Size getOffsetOfOpaqueIsolationField(IRGenModule &IGM,
                                       const LoadableTypeInfo &isolationTI) {
   auto offset = IGM.RefCountedStructSize;
@@ -990,9 +1029,7 @@ class PartialApplicationForwarderEmission {
     if (nativeResultSchema.requiresIndirect()) {
       assert(origNativeSchema.requiresIndirect());
       auto resultAddr = origParams.claimNext();
-      resultAddr = subIGF.Builder.CreateBitCast(
-          resultAddr, IGM.getStoragePointerType(origConv.getSILResultType(
-                          IGM.getMaximalTypeExpansionContext())));
+      resultAddr = subIGF.Builder.CreateBitCast(resultAddr, IGM.PtrTy);
       args.add(resultAddr);
       useSRet = false;
     } else if (origNativeSchema.requiresIndirect()) {
@@ -1014,8 +1051,7 @@ class PartialApplicationForwarderEmission {
     for (auto resultType : origConv.getIndirectSILResultTypes(
              IGM.getMaximalTypeExpansionContext())) {
       auto addr = origParams.claimNext();
-      addr = subIGF.Builder.CreateBitCast(
-          addr, IGM.getStoragePointerType(resultType));
+      addr = subIGF.Builder.CreateBitCast(addr, IGM.PtrTy);
       auto useOpaque =
           useSRet && !isa<FixedTypeInfo>(IGM.getTypeInfo(resultType));
       if (useOpaque)
@@ -1041,9 +1077,8 @@ class PartialApplicationForwarderEmission {
       bool isIndirectParam = origConv.isSILIndirect(origParamInfo);
       if (!isIndirectParam && nativeSchemaOrigParam.requiresIndirect()) {
         auto addr = origParams.claimNext();
-        if (addr->getType() != ti.getStorageType()->getPointerTo())
-          addr = subIGF.Builder.CreateBitCast(addr,
-                                           ti.getStorageType()->getPointerTo());
+        if (addr->getType() != IGM.PtrTy)
+          addr = subIGF.Builder.CreateBitCast(addr, IGM.PtrTy);
         args.add(addr);
         continue;
       }
@@ -1456,7 +1491,8 @@ class CoroPartialApplicationForwarderEmission
     auto prototype = subIGF.IGM.getOpaquePtr(
       subIGF.IGM.getAddrOfContinuationPrototype(
         cast<SILFunctionType>(
-          unsubstType->mapTypeOutOfContext()->getCanonicalType())));
+          unsubstType->mapTypeOutOfContext()->getCanonicalType()),
+        origType->getInvocationGenericSignature()));
 
     
     // Use free as our allocator.
@@ -1466,9 +1502,9 @@ class CoroPartialApplicationForwarderEmission
     llvm::Value *buffer = origParams.claimNext();
     llvm::Value *id;
     if (subIGF.IGM.getOptions().EmitTypeMallocForCoroFrame) {
-      // Use swift_coroFrameAlloc as our allocator.
-    auto coroAllocFn = subIGF.IGM.getOpaquePtr(subIGF.IGM.getCoroFrameAllocFn());
-    auto mallocTypeId = subIGF.getMallocTypeId();
+      // Use swift_coroFrameAllocStub to emit our allocator.
+      auto coroAllocFn = subIGF.IGM.getOpaquePtr(getCoroFrameAllocStubFn(subIGF.IGM));
+      auto mallocTypeId = subIGF.getMallocTypeId();
       id = subIGF.Builder.CreateIntrinsicCall(
         llvm::Intrinsic::coro_id_retcon_once,
         {llvm::ConstantInt::get(
@@ -2129,7 +2165,7 @@ static llvm::Value *emitPartialApplicationForwarder(
   }
 
   // Derive the callee function pointer.
-  auto fnTy = origSig.getType()->getPointerTo();
+  auto *fnTy = IGM.PtrTy;
   FunctionPointer fnPtr = [&]() -> FunctionPointer {
     // If we found a function pointer statically, great.
     if (staticFnPtr) {
@@ -2638,8 +2674,8 @@ static llvm::Function *emitBlockCopyHelper(IRGenModule &IGM,
   
   // Create the helper.
   llvm::Type *args[] = {
-    blockTL.getStorageType()->getPointerTo(),
-    blockTL.getStorageType()->getPointerTo(),
+      IGM.PtrTy,
+      IGM.PtrTy,
   };
   auto copyTy = llvm::FunctionType::get(IGM.VoidTy, args, /*vararg*/ false);
   // TODO: Give these predictable mangled names and shared linkage.
@@ -2677,9 +2713,8 @@ static llvm::Function *emitBlockDisposeHelper(IRGenModule &IGM,
   // TODO
   
   // Create the helper.
-  auto destroyTy = llvm::FunctionType::get(IGM.VoidTy,
-                                       blockTL.getStorageType()->getPointerTo(),
-                                       /*vararg*/ false);
+  auto destroyTy = llvm::FunctionType::get(IGM.VoidTy, IGM.PtrTy,
+                                           /*vararg*/ false);
   // TODO: Give these predictable mangled names and shared linkage.
   auto func = llvm::Function::Create(destroyTy,
                                      llvm::GlobalValue::InternalLinkage,
@@ -2715,14 +2750,17 @@ void irgen::emitBlockHeader(IRGenFunction &IGF,
     = IGF.getTypeInfoForLowered(blockTy).as<BlockStorageTypeInfo>();
 
   Address headerAddr = storageTL.projectBlockHeader(IGF, storage);
-  
+
   //
   // Initialize the "isa" pointer, which is _NSConcreteStackBlock.
   auto NSConcreteStackBlock =
       IGF.IGM.getModule()->getOrInsertGlobal("_NSConcreteStackBlock",
                                              IGF.IGM.ObjCClassStructTy);
-  ApplyIRLinkage(IRLinkage::ExternalImport)
-      .to(cast<llvm::GlobalVariable>(NSConcreteStackBlock));
+  swift::ClangImporter *CI =
+      static_cast<ClangImporter *>(IGF.IGM.Context.getClangModuleLoader());
+  if (!CI->getCodeGenOpts().StaticClosure)
+    ApplyIRLinkage(IRLinkage::ExternalImport)
+        .to(cast<llvm::GlobalVariable>(NSConcreteStackBlock));
 
   //
   // Set the flags.
@@ -2808,8 +2846,7 @@ void irgen::emitBlockHeader(IRGenFunction &IGF,
                           IGF.Builder.CreateStructGEP(headerAddr, 4, layout));
 }
 
-llvm::Value *
-IRGenFunction::emitAsyncResumeProjectContext(llvm::Value *calleeContext) {
+llvm::Value *IRGenFunction::popAsyncContext(llvm::Value *calleeContext) {
   auto addr = Builder.CreateBitOrPointerCast(calleeContext, IGM.Int8PtrPtrTy);
   Address callerContextAddr(addr, IGM.Int8PtrTy, IGM.getPointerAlignment());
   llvm::Value *callerContext = Builder.CreateLoad(callerContextAddr);
@@ -2818,6 +2855,13 @@ IRGenFunction::emitAsyncResumeProjectContext(llvm::Value *calleeContext) {
         PointerAuthInfo::emit(*this, schema, addr, PointerAuthEntity());
     callerContext = emitPointerAuthAuth(*this, callerContext, authInfo);
   }
+  return callerContext;
+}
+
+llvm::Value *
+IRGenFunction::emitAsyncResumeProjectContext(llvm::Value *calleeContext) {
+  auto  callerContext = popAsyncContext(calleeContext);
+
   // TODO: remove this once all platforms support lowering the intrinsic.
   // At the time of this writing only arm64 supports it.
   if (IGM.TargetInfo.canUseSwiftAsyncContextAddrIntrinsic()) {
diff --git a/lib/IRGen/GenFunc.h b/lib/IRGen/GenFunc.h
index 662e0ab30498e..922db3e939b86 100644
--- a/lib/IRGen/GenFunc.h
+++ b/lib/IRGen/GenFunc.h
@@ -61,6 +61,10 @@ namespace irgen {
       CanSILFunctionType outType, Explosion &out, bool isOutlined);
   CanType getArgumentLoweringType(CanType type, SILParameterInfo paramInfo,
                                   bool isNoEscape);
+
+  /// Stub function that weakly links againt the swift_coroFrameAlloc
+  /// function. This is required for back-deployment.
+  llvm::Constant *getCoroFrameAllocStubFn(IRGenModule &IGM);
 } // end namespace irgen
 } // end namespace swift
 
diff --git a/lib/IRGen/GenHeap.cpp b/lib/IRGen/GenHeap.cpp
index a14ade624eaa7..199a50f1fd3d1 100644
--- a/lib/IRGen/GenHeap.cpp
+++ b/lib/IRGen/GenHeap.cpp
@@ -877,7 +877,7 @@ static void emitUnaryRefCountCall(IRGenFunction &IGF,
                         ? IGF.IGM.VoidTy
                         : value->getType();
     fnType = llvm::FunctionType::get(resultTy, value->getType(), false);
-    fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
+    fn = llvm::ConstantExpr::getBitCast(fn, IGF.IGM.PtrTy);
   }
 
   // Emit the call.
@@ -909,7 +909,7 @@ static void emitCopyLikeCall(IRGenFunction &IGF,
     auto resultTy = fnType->getReturnType() == IGF.IGM.VoidTy ? IGF.IGM.VoidTy
                                                               : dest->getType();
     fnType = llvm::FunctionType::get(resultTy, paramTypes, false);
-    fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
+    fn = llvm::ConstantExpr::getBitCast(fn, IGF.IGM.PtrTy);
   }
 
   // Emit the call.
@@ -941,7 +941,7 @@ static llvm::Value *emitLoadWeakLikeCall(IRGenFunction &IGF,
   if (resultType != fnType->getReturnType()) {
     llvm::Type *paramTypes[] = { addr->getType() };
     fnType = llvm::FunctionType::get(resultType, paramTypes, false);
-    fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
+    fn = llvm::ConstantExpr::getBitCast(fn, IGF.IGM.PtrTy);
   }
 
   // Emit the call.
@@ -974,7 +974,7 @@ static void emitStoreWeakLikeCall(IRGenFunction &IGF,
     auto resultTy = fnType->getReturnType() == IGF.IGM.VoidTy ? IGF.IGM.VoidTy
                                                               : addr->getType();
     fnType = llvm::FunctionType::get(resultTy, paramTypes, false);
-    fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
+    fn = llvm::ConstantExpr::getBitCast(fn, IGF.IGM.PtrTy);
   }
 
   // Emit the call.
@@ -1528,8 +1528,7 @@ class NonFixedBoxTypeInfo final : public BoxTypeInfo {
     auto metadata = IGF.emitTypeMetadataRefForLayout(boxedType);
     llvm::Value *box, *address;
     IGF.emitAllocBoxCall(metadata, box, address);
-    address = IGF.Builder.CreateBitCast(address,
-                                        ti.getStorageType()->getPointerTo());
+    address = IGF.Builder.CreateBitCast(address, IGF.IGM.PtrTy);
     return {ti.getAddressForPointer(address), box};
   }
 
@@ -1546,8 +1545,7 @@ class NonFixedBoxTypeInfo final : public BoxTypeInfo {
     auto &ti = IGF.getTypeInfo(boxedType);
     auto metadata = IGF.emitTypeMetadataRefForLayout(boxedType);
     llvm::Value *address = IGF.emitProjectBoxCall(box, metadata);
-    address = IGF.Builder.CreateBitCast(address,
-                                        ti.getStorageType()->getPointerTo());
+    address = IGF.Builder.CreateBitCast(address, IGF.IGM.PtrTy);
     return ti.getAddressForPointer(address);
   }
 };
@@ -1578,24 +1576,6 @@ class FixedBoxTypeInfoBase : public BoxTypeInfo {
       boxedInterfaceType = boxedType.mapTypeOutOfContext();
     }
 
-    {
-      // FIXME: This seems wrong. We used to just mangle opened archetypes as
-      // their interface type. Let's make that explicit now.
-      auto astType = boxedInterfaceType.getASTType();
-      astType =
-          astType
-              .transformRec([](Type t) -> std::optional<Type> {
-                if (auto *openedExistential = t->getAs<ExistentialArchetypeType>()) {
-                  auto &ctx = openedExistential->getASTContext();
-                  return GenericTypeParamType::getType(0, 0, ctx);
-                }
-                return std::nullopt;
-              })
-              ->getCanonicalType();
-      boxedInterfaceType = SILType::getPrimitiveType(
-          astType, boxedInterfaceType.getCategory());
-    }
-    
     auto boxDescriptor = IGF.IGM.getAddrOfBoxDescriptor(
         boxedInterfaceType,
         env ? env->getGenericSignature().getCanonicalSignature()
@@ -1839,13 +1819,11 @@ Address irgen::emitAllocateExistentialBoxInBuffer(
   OwnedAddress owned = boxTI.allocate(IGF, env, boxType, name);
   Explosion box;
   box.add(owned.getOwner());
-  boxTI.initialize(IGF, box,
-                   Address(IGF.Builder.CreateBitCast(
-                               destBuffer.getAddress(),
-                               owned.getOwner()->getType()->getPointerTo()),
-                           owned.getOwner()->getType(),
-                           destBuffer.getAlignment()),
-                   isOutlined);
+  boxTI.initialize(
+      IGF, box,
+      Address(IGF.Builder.CreateBitCast(destBuffer.getAddress(), IGF.IGM.PtrTy),
+              owned.getOwner()->getType(), destBuffer.getAlignment()),
+      isOutlined);
   return owned.getAddress();
 }
 
@@ -1958,8 +1936,7 @@ llvm::Value *IRGenFunction::getDynamicSelfMetadata() {
 llvm::Value *irgen::emitLoadOfObjCHeapMetadataRef(IRGenFunction &IGF,
                                                   llvm::Value *object) {
   if (IGF.IGM.TargetInfo.hasISAMasking()) {
-    object = IGF.Builder.CreateBitCast(object,
-                                       IGF.IGM.IntPtrTy->getPointerTo());
+    object = IGF.Builder.CreateBitCast(object, IGF.IGM.PtrTy);
     llvm::Value *metadata = IGF.Builder.CreateLoad(
         Address(object, IGF.IGM.IntPtrTy, IGF.IGM.getPointerAlignment()));
     llvm::Value *mask = IGF.Builder.CreateLoad(IGF.IGM.getAddrOfObjCISAMask());
@@ -1969,8 +1946,7 @@ llvm::Value *irgen::emitLoadOfObjCHeapMetadataRef(IRGenFunction &IGF,
   } else if (IGF.IGM.TargetInfo.hasOpaqueISAs()) {
     return emitHeapMetadataRefForUnknownHeapObject(IGF, object);
   } else {
-    object = IGF.Builder.CreateBitCast(object,
-                                  IGF.IGM.TypeMetadataPtrTy->getPointerTo());
+    object = IGF.Builder.CreateBitCast(object, IGF.IGM.PtrTy);
     llvm::Value *metadata = IGF.Builder.CreateLoad(Address(
         object, IGF.IGM.TypeMetadataPtrTy, IGF.IGM.getPointerAlignment()));
     return metadata;
diff --git a/lib/IRGen/GenIntegerLiteral.cpp b/lib/IRGen/GenIntegerLiteral.cpp
index a39663e3a59d4..6adc92ea847e7 100644
--- a/lib/IRGen/GenIntegerLiteral.cpp
+++ b/lib/IRGen/GenIntegerLiteral.cpp
@@ -111,11 +111,9 @@ class IntegerLiteralTypeInfo :
 
 llvm::StructType *IRGenModule::getIntegerLiteralTy() {
   if (!IntegerLiteralTy) {
-    IntegerLiteralTy =
-      llvm::StructType::create(getLLVMContext(), {
-                                 SizeTy->getPointerTo(),
-                                 SizeTy
-                               }, "swift.int_literal");
+    IntegerLiteralTy = llvm::StructType::create(
+        getLLVMContext(), {PtrTy, SizeTy},
+        "swift.int_literal");
   }
   return IntegerLiteralTy;
 }
diff --git a/lib/IRGen/GenKeyPath.cpp b/lib/IRGen/GenKeyPath.cpp
index 7d022357c2169..314c59149fd6b 100644
--- a/lib/IRGen/GenKeyPath.cpp
+++ b/lib/IRGen/GenKeyPath.cpp
@@ -311,8 +311,8 @@ getWitnessTableForComputedComponent(IRGenModule &IGM,
         }
         auto elt =
             IGF.Builder.CreateInBoundsGEP(IGM.Int8Ty, componentArgsBuf, offset);
-        auto eltAddr = ti.getAddressForPointer(
-          IGF.Builder.CreateBitCast(elt, ti.getStorageType()->getPointerTo()));
+        auto eltAddr =
+            ti.getAddressForPointer(IGF.Builder.CreateBitCast(elt, IGM.PtrTy));
         ti.destroy(IGF, eltAddr, ty,
                    true /*witness table: need it to be fast*/);
         auto size = ti.getSize(IGF, ty);
@@ -365,11 +365,9 @@ getWitnessTableForComputedComponent(IRGenModule &IGM,
         auto destElt =
             IGF.Builder.CreateInBoundsGEP(IGM.Int8Ty, destArgsBuf, offset);
         auto sourceEltAddr = ti.getAddressForPointer(
-          IGF.Builder.CreateBitCast(sourceElt,
-                                    ti.getStorageType()->getPointerTo()));
+            IGF.Builder.CreateBitCast(sourceElt, IGM.PtrTy));
         auto destEltAddr = ti.getAddressForPointer(
-          IGF.Builder.CreateBitCast(destElt,
-                                    ti.getStorageType()->getPointerTo()));
+            IGF.Builder.CreateBitCast(destElt, IGM.PtrTy));
 
         ti.initializeWithCopy(IGF, destEltAddr, sourceEltAddr, ty, false);
         auto size = ti.getSize(IGF, ty);
@@ -495,8 +493,8 @@ getInitializerForComputedComponent(IRGenModule &IGM,
       }
 
       auto ptr = IGF.Builder.CreateInBoundsGEP(IGM.Int8Ty, src, offset);
-      auto addr = ti.getAddressForPointer(IGF.Builder.CreateBitCast(
-        ptr, ti.getStorageType()->getPointerTo()));
+      auto addr =
+          ti.getAddressForPointer(IGF.Builder.CreateBitCast(ptr, IGM.PtrTy));
       srcAddresses.push_back(addr);
       
       auto size = ti.getSize(IGF, ty);
@@ -524,9 +522,9 @@ getInitializerForComputedComponent(IRGenModule &IGM,
       }
 
       auto ptr = IGF.Builder.CreateInBoundsGEP(IGM.Int8Ty, dest, offset);
-      auto destAddr = ti.getAddressForPointer(IGF.Builder.CreateBitCast(
-        ptr, ti.getStorageType()->getPointerTo()));
-      
+      auto destAddr =
+          ti.getAddressForPointer(IGF.Builder.CreateBitCast(ptr, IGM.PtrTy));
+
       // The last component using an operand can move the value out of the
       // buffer.
       if (&component == operands[index.Operand].LastUser) {
@@ -783,7 +781,7 @@ emitKeyPathComponent(IRGenModule &IGM,
                                 if (auto *openedExistential =
                                         t->getAs<ExistentialArchetypeType>()) {
                                   auto &ctx = openedExistential->getASTContext();
-                                  return GenericTypeParamType::getType(0, 0, ctx);
+                                  return ctx.TheSelfType;
                                 }
                                 return std::nullopt;
                               })
@@ -1145,6 +1143,7 @@ IRGenModule::getAddrOfKeyPathPattern(KeyPathPattern *pattern,
   // null otherwise.
   if (!pattern->getObjCString().empty()) {
     auto objcString = getAddrOfGlobalString(pattern->getObjCString(),
+                                            CStringSectionType::Default,
                                             /*relatively addressed*/ true);
     fields.addRelativeAddress(objcString);
   } else {
@@ -1360,8 +1359,8 @@ std::pair<llvm::Value *, llvm::Value *> irgen::emitKeyPathArgument(
     auto &ti = IGF.getTypeInfo(operandTy);
     auto ptr = IGF.Builder.CreateInBoundsGEP(IGM.Int8Ty, argsBuf.getAddress(),
                                              operandOffsets[i]);
-    auto addr = ti.getAddressForPointer(
-        IGF.Builder.CreateBitCast(ptr, ti.getStorageType()->getPointerTo()));
+    auto addr =
+        ti.getAddressForPointer(IGF.Builder.CreateBitCast(ptr, IGM.PtrTy));
     if (operandTy.isAddress()) {
       ti.initializeWithTake(IGF, addr, ti.getAddressForPointer(indiceValues.claimNext()),
                             operandTy, false, /*zeroizeIfSensitive=*/ true);
diff --git a/lib/IRGen/GenMeta.cpp b/lib/IRGen/GenMeta.cpp
index 26dbc957695d3..8adb7bdaf87a7 100644
--- a/lib/IRGen/GenMeta.cpp
+++ b/lib/IRGen/GenMeta.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -21,7 +21,6 @@
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/Attr.h"
-#include "swift/AST/CanTypeVisitor.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/DiagnosticsIRGen.h"
 #include "swift/AST/GenericEnvironment.h"
@@ -255,34 +254,47 @@ static Flags getMethodDescriptorFlags(ValueDecl *fn) {
     return flags;
   }
 
-  auto kind = [&] {
+  auto kindAndIsCalleeAllocatedCoroutine =
+      [&]() -> std::pair<typename Flags::Kind, bool> {
     auto accessor = dyn_cast<AccessorDecl>(fn);
-    if (!accessor) return Flags::Kind::Method;
+    if (!accessor)
+      return {Flags::Kind::Method, false};
     switch (accessor->getAccessorKind()) {
     case AccessorKind::Get:
-      return Flags::Kind::Getter;
+      return {Flags::Kind::Getter, false};
     case AccessorKind::Set:
-      return Flags::Kind::Setter;
+      return {Flags::Kind::Setter, false};
     case AccessorKind::Read:
-      return Flags::Kind::ReadCoroutine;
+      return {Flags::Kind::ReadCoroutine, false};
     case AccessorKind::Read2:
-      return Flags::Kind::Read2Coroutine;
+      return {Flags::Kind::ReadCoroutine, true};
     case AccessorKind::Modify:
-      return Flags::Kind::ModifyCoroutine;
+      return {Flags::Kind::ModifyCoroutine, false};
     case AccessorKind::Modify2:
-      return Flags::Kind::Modify2Coroutine;
-#define OPAQUE_ACCESSOR(ID, KEYWORD)
-#define ACCESSOR(ID) \
-    case AccessorKind::ID:
+      return {Flags::Kind::ModifyCoroutine, true};
     case AccessorKind::DistributedGet:
+      return {Flags::Kind::Getter, false};
+#define OPAQUE_ACCESSOR(ID, KEYWORD)
+#define ACCESSOR(ID, KEYWORD) case AccessorKind::ID:
 #include "swift/AST/AccessorKinds.def"
       llvm_unreachable("these accessors never appear in protocols or v-tables");
     }
     llvm_unreachable("bad kind");
   }();
-  bool hasAsync = false;
+  auto kind = kindAndIsCalleeAllocatedCoroutine.first;
+
+  // Because no async old-ABI accessor coroutines exist or presumably ever will
+  // (if async coroutines accessors are added, they will presumably be new-ABI),
+  // the pairs {Flags::Kind::ReadCoroutine, isAsync} and
+  // {Flags::Kind::ModifyCoroutine, isAsync} can't mean "async old-ABI
+  // accessor coroutine".  As such, we repurpose that pair to mean "new-ABI
+  // accessor coroutine".  This has the important virtue of resulting in ptrauth
+  // authing/signing coro function pointers as data on old OSes where the bit
+  // means "async" and where adding new accessor kinds requires a back
+  // deployment library.
+  bool hasAsync = kindAndIsCalleeAllocatedCoroutine.second;
   if (auto *afd = dyn_cast<AbstractFunctionDecl>(fn))
-    hasAsync = afd->hasAsync();
+    hasAsync |= afd->hasAsync();
   return Flags(kind).withIsInstance(!fn->isStatic()).withIsAsync(hasAsync);
 }
 
@@ -569,8 +581,7 @@ namespace {
     void addGenericParameters() {
       GenericSignature sig = asImpl().getGenericSignature();
       auto metadata =
-        irgen::addGenericParameters(IGM, B,
-                                    asImpl().getGenericSignature(),
+        irgen::addGenericParameters(IGM, B, sig,
                                     /*implicit=*/false);
       assert(metadata.NumParams == metadata.NumParamsEmitted &&
              "We can't use implicit GenericParamDescriptors here");
@@ -834,8 +845,8 @@ namespace {
       IRGenMangler mangler(IGM.Context);
       auto mangledName = mangler.mangleAnonymousDescriptorName(Name);
       auto mangledNameConstant =
-        IGM.getAddrOfGlobalString(mangledName,
-                                  /*willBeRelativelyAddressed*/ true);
+          IGM.getAddrOfGlobalString(mangledName, CStringSectionType::Default,
+                                    /*willBeRelativelyAddressed*/ true);
       B.addRelativeAddress(mangledNameConstant);
     }
 
@@ -953,8 +964,7 @@ namespace {
         auto flags = Flags(Flags::Kind::AssociatedTypeAccessFunction);
         if (auto &schema = IGM.getOptions().PointerAuth
                               .ProtocolAssociatedTypeAccessFunctions) {
-          addDiscriminator(flags, schema,
-                           AssociatedType(entry.getAssociatedType()));
+          addDiscriminator(flags, schema, entry.getAssociatedType());
         }
 
         // Look for a default witness.
@@ -988,8 +998,7 @@ namespace {
 
       // Emit the dispatch thunk.
       auto shouldEmitDispatchThunk =
-          (Resilient || IGM.getOptions().WitnessMethodElimination) &&
-          !func.isDistributed();
+          Resilient || IGM.getOptions().WitnessMethodElimination;
       if (shouldEmitDispatchThunk) {
         IGM.emitDispatchThunk(func);
       }
@@ -1058,26 +1067,13 @@ namespace {
       }
 
       for (auto &entry : pi.getWitnessEntries()) {
-        if (entry.isFunction() &&
-            entry.getFunction().getDecl()->isDistributedGetAccessor()) {
-          // We avoid emitting _distributed_get accessors, as they cannot be
-          // referred to anyway
-          continue;
-        }
-
         if (Resilient) {
           if (entry.isFunction()) {
             // Define the method descriptor.
             SILDeclRef func(entry.getFunction());
 
-            /// Distributed thunks don't need resilience.
-            if (func.isDistributedThunk()) {
-              continue;
-            }
-
             auto *descriptor =
-              B.getAddrOfCurrentPosition(
-                IGM.ProtocolRequirementStructTy);
+                B.getAddrOfCurrentPosition(IGM.ProtocolRequirementStructTy);
             IGM.defineMethodDescriptor(func, Proto, descriptor,
                                        IGM.ProtocolRequirementStructTy);
           }
@@ -1281,6 +1277,7 @@ namespace {
       llvm::Constant *global = nullptr;
       if (!AssociatedTypeNames.empty()) {
         global = IGM.getAddrOfGlobalString(AssociatedTypeNames,
+                                           CStringSectionType::Default,
                                            /*willBeRelativelyAddressed=*/true);
       }
       B.addRelativeAddressOrNull(global);
@@ -1394,12 +1391,13 @@ namespace {
 
       // Create placeholders for the counts of the conditional requirements
       // for each conditional conformance to a supressible protocol.
-      unsigned numProtocols = countBitsUsed(protocols.rawBits());
+      unsigned numProtocols = 0;
       using PlaceholderPosition =
           ConstantAggregateBuilderBase::PlaceholderPosition;
       SmallVector<PlaceholderPosition, 2> countPlaceholders;
-      for (unsigned i : range(0, numProtocols)) {
-        (void)i;
+      for (auto kind : protocols) {
+        (void)kind;
+        numProtocols++;
         countPlaceholders.push_back(
             B.addPlaceholderWithSize(IGM.Int16Ty));
       }
@@ -1518,9 +1516,10 @@ namespace {
         name.pop_back();
         assert(name.back() == '\0');
       }
-      
-      auto nameStr = IGM.getAddrOfGlobalString(name,
-                                               /*willBeRelativelyAddressed*/ true);
+
+      auto nameStr =
+          IGM.getAddrOfGlobalString(name, CStringSectionType::Default,
+                                    /*willBeRelativelyAddressed*/ true);
       B.addRelativeAddress(nameStr);
     }
       
@@ -1835,7 +1834,7 @@ namespace {
     
     void addLayoutInfo() {
       // uint32_t NumFields;
-      B.addInt32(getNumFields(getType()));
+      B.addInt32(countExportableFields(IGM, getType()));
 
       // uint32_t FieldOffsetVectorOffset;
       B.addInt32(FieldVectorOffset / IGM.getPointerSize());
@@ -2410,7 +2409,7 @@ namespace {
       B.addInt32(numImmediateMembers);
 
       // uint32_t NumFields;
-      B.addInt32(getNumFields(getType()));
+      B.addInt32(countExportableFields(IGM, getType()));
 
       // uint32_t FieldOffsetVectorOffset;
       B.addInt32(getFieldVectorOffset() / IGM.getPointerSize());
@@ -2705,30 +2704,30 @@ namespace {
 
             // Emit a #available condition check, if it's `false` -
             // jump to the next conditionally available type.
-            auto conditions = underlyingTy->getAvailability();
+            auto queries = underlyingTy->getAvailabilityQueries();
 
             SmallVector<llvm::BasicBlock *, 4> conditionBlocks;
-            for (unsigned condIndex : indices(conditions)) {
+            for (unsigned queryIndex : indices(queries)) {
               // cond-<type_idx>-<cond_index>
               conditionBlocks.push_back(IGF.createBasicBlock(
-                  "cond-" + llvm::utostr(i) + "-" + llvm::utostr(condIndex)));
+                  "cond-" + llvm::utostr(i) + "-" + llvm::utostr(queryIndex)));
             }
 
             // Jump to the first condition.
             IGF.Builder.CreateBr(conditionBlocks.front());
 
-            for (unsigned condIndex : indices(conditions)) {
-              const auto &condition = conditions[condIndex];
+            for (unsigned queryIndex : indices(queries)) {
+              const auto &query = queries[queryIndex];
 
-              assert(condition.first.hasLowerEndpoint());
+              assert(query.getPrimaryArgument());
 
-              bool isUnavailability = condition.second;
-              auto version = condition.first.getLowerEndpoint();
+              bool isUnavailability = query.isUnavailability();
+              auto version = query.getPrimaryArgument().value();
               auto *major = getInt32Constant(version.getMajor());
               auto *minor = getInt32Constant(version.getMinor());
               auto *patch = getInt32Constant(version.getSubminor());
 
-              IGF.Builder.emitBlock(conditionBlocks[condIndex]);
+              IGF.Builder.emitBlock(conditionBlocks[queryIndex]);
 
               auto isAtLeast =
                   IGF.emitTargetOSVersionAtLeastCall(major, minor, patch);
@@ -2743,9 +2742,9 @@ namespace {
                     IGF.Builder.CreateXor(success, IGF.Builder.getIntN(1, -1));
               }
 
-              auto nextCondOrRet = condIndex == conditions.size() - 1
+              auto nextCondOrRet = queryIndex == queries.size() - 1
                                        ? returnTypeBB
-                                       : conditionBlocks[condIndex + 1];
+                                       : conditionBlocks[queryIndex + 1];
 
               IGF.Builder.CreateCondBr(success, nextCondOrRet,
                                        conditionalTypes[i + 1]);
@@ -2762,8 +2761,8 @@ namespace {
           IGF.Builder.emitBlock(conditionalTypes.back());
           auto universal = substitutionSet.back();
 
-          assert(universal->getAvailability().size() == 1 &&
-                 universal->getAvailability()[0].first.isAll());
+          assert(universal->getAvailabilityQueries().size() == 1 &&
+                 universal->getAvailabilityQueries()[0].isConstant());
 
           IGF.Builder.CreateRet(
               getResultValue(IGF, genericEnv, universal->getSubstitutions()));
@@ -2877,9 +2876,10 @@ namespace {
             substitutions.lookupConformance(underlyingDependentType, P);
 
         if (underlyingType->hasTypeParameter()) {
-          std::tie(underlyingType, underlyingConformance)
-              = GenericEnvironment::mapConformanceRefIntoContext(
-                    genericEnv, underlyingType, underlyingConformance);
+          underlyingType = genericEnv->mapTypeIntoContext(
+              underlyingType);
+          underlyingConformance = underlyingConformance.subst(
+            genericEnv->getForwardingSubstitutionMap());
         }
 
         return emitWitnessTableRef(IGF, underlyingType->getCanonicalType(),
@@ -2995,8 +2995,9 @@ void irgen::emitLazyMetadataAccessor(IRGenModule &IGM,
   if (IGM.getOptions().optimizeForSize())
     accessor->addFnAttr(llvm::Attribute::NoInline);
 
-  bool isReadNone = (genericArgs.Types.size() <=
-                     NumDirectGenericTypeMetadataAccessFunctionArgs);
+  bool isReadNone =
+      !genericArgs.hasPacks && (genericArgs.Types.size() <=
+                                NumDirectGenericTypeMetadataAccessFunctionArgs);
 
   emitCacheAccessFunction(
       IGM, accessor, /*cache*/ nullptr, /*cache type*/ nullptr,
@@ -3151,7 +3152,7 @@ emitInitializeFieldOffsetVector(SILType T, llvm::Value *metadata,
   }
 
   // Collect the stored properties of the type.
-  unsigned numFields = getNumFields(target);
+  unsigned numFields = countExportableFields(IGM, target);
 
   // Fill out an array with the field type metadata records.
   Address fields = createAlloca(
@@ -3164,6 +3165,9 @@ emitInitializeFieldOffsetVector(SILType T, llvm::Value *metadata,
   forEachField(IGM, target, [&](Field field) {
     assert(field.isConcrete() &&
            "initializing offset vector for type with missing member?");
+    if (!isExportableField(field))
+      return;
+
     SILType propTy = field.getType(IGM, T);
     llvm::Value *fieldLayout = emitTypeLayoutRef(*this, propTy, collector);
     Address fieldLayoutAddr =
@@ -3271,7 +3275,7 @@ static void emitInitializeFieldOffsetVectorWithLayoutString(
       emitAddressOfFieldOffsetVector(IGF, metadata, target).getAddress();
 
   // Collect the stored properties of the type.
-  unsigned numFields = getNumFields(target);
+  unsigned numFields = countExportableFields(IGM, target);
 
   // Ask the runtime to lay out the struct or class.
   auto numFieldsV = IGM.getSize(Size(numFields));
@@ -3294,6 +3298,9 @@ static void emitInitializeFieldOffsetVectorWithLayoutString(
   forEachField(IGM, target, [&](Field field) {
     assert(field.isConcrete() &&
            "initializing offset vector for type with missing member?");
+    if (!isExportableField(field))
+      return;
+
     SILType propTy = field.getType(IGM, T);
     llvm::Value *fieldMetatype;
     llvm::Value *fieldTag;
@@ -3370,9 +3377,9 @@ static void emitInitializeRawLayoutOldOld(IRGenFunction &IGF, SILType likeType,
   // This is the list of field type layouts that we're going to pass to the init
   // function. This will only ever hold 1 field which is the temporary one we're
   // going to build up from our like type's layout.
-  auto fieldLayouts = IGF.createAlloca(
-                          llvm::ArrayType::get(IGM.TypeLayoutTy->getPointerTo(), 1),
-                          IGM.getPointerAlignment(), "fieldLayouts");
+  auto fieldLayouts =
+      IGF.createAlloca(llvm::ArrayType::get(IGM.PtrTy, 1),
+                       IGM.getPointerAlignment(), "fieldLayouts");
   IGF.Builder.CreateLifetimeStart(fieldLayouts, IGM.getPointerSize());
 
   // We're going to pretend that this is our field offset vector for the init to
@@ -4612,7 +4619,7 @@ namespace {
         } else if (accessor && requiresFeatureCoroutineAccessors(
                                    accessor->getAccessorKind())) {
           ptr = llvm::ConstantExpr::getBitCast(
-              IGM.getDeletedCalleeAllocatedCoroutineMethodErrorAsyncFunctionPointer(),
+              IGM.getDeletedCalleeAllocatedCoroutineMethodErrorCoroFunctionPointer(),
               IGM.FunctionPtrTy);
         } else {
           ptr = llvm::ConstantExpr::getBitCast(IGM.getDeletedMethodErrorFn(),
@@ -5802,8 +5809,12 @@ namespace {
         return false;
       }
 
-      if (IGM.Context.LangOpts.hasFeature(Feature::LayoutStringValueWitnessesInstantiation) &&
-          IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation) {
+      auto &TI = IGM.getTypeInfo(getLoweredType());
+
+      if (IGM.Context.LangOpts.hasFeature(
+              Feature::LayoutStringValueWitnessesInstantiation) &&
+          IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation &&
+          TI.isCopyable(ResilienceExpansion::Maximal)) {
         return !!getLayoutString() || needsSingletonMetadataInitialization(IGM, Target);
       }
 
@@ -6008,12 +6019,14 @@ namespace {
       if (!layoutStringsEnabled(IGM)) {
         return false;
       }
-      return !!getLayoutString() ||
-             (IGM.Context.LangOpts.hasFeature(
-                 Feature::LayoutStringValueWitnessesInstantiation) &&
-              IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation &&
-                    (HasDependentVWT || HasDependentMetadata) &&
-                      !isa<FixedTypeInfo>(IGM.getTypeInfo(getLoweredType())));
+      const auto &TI = IGM.getTypeInfo(getLoweredType());
+      return (!!getLayoutString() ||
+              (IGM.Context.LangOpts.hasFeature(
+                   Feature::LayoutStringValueWitnessesInstantiation) &&
+               IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation &&
+               (HasDependentVWT || HasDependentMetadata) &&
+               !isa<FixedTypeInfo>(TI))) &&
+             TI.isCopyable(ResilienceExpansion::Maximal);
     }
 
     llvm::Constant *emitNominalTypeDescriptor() {
@@ -6277,9 +6290,11 @@ namespace {
     }
 
     bool hasInstantiatedLayoutString() {
+      auto &TI = IGM.getTypeInfo(getLoweredType());
       if (IGM.Context.LangOpts.hasFeature(
               Feature::LayoutStringValueWitnessesInstantiation) &&
-          IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation) {
+          IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation &&
+          TI.isCopyable(ResilienceExpansion::Maximal)) {
         return needsSingletonMetadataInitialization(IGM, Target);
       }
 
@@ -6541,13 +6556,15 @@ namespace {
       if (!layoutStringsEnabled(IGM)) {
         return false;
       }
+      auto &TI = IGM.getTypeInfo(getLoweredType());
 
-      return !!getLayoutString() ||
-             (IGM.Context.LangOpts.hasFeature(
-                  Feature::LayoutStringValueWitnessesInstantiation) &&
-              IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation &&
-              (HasDependentVWT || HasDependentMetadata) &&
-              !isa<FixedTypeInfo>(IGM.getTypeInfo(getLoweredType())));
+      return (!!getLayoutString() ||
+              (IGM.Context.LangOpts.hasFeature(
+                   Feature::LayoutStringValueWitnessesInstantiation) &&
+               IGM.getOptions().EnableLayoutStringValueWitnessesInstantiation &&
+               (HasDependentVWT || HasDependentMetadata) &&
+               !isa<FixedTypeInfo>(TI))) &&
+             TI.isCopyable(ResilienceExpansion::Maximal);
     }
 
     llvm::Constant *emitNominalTypeDescriptor() {
@@ -6760,7 +6777,8 @@ namespace {
         return;
       }
 
-      // Emit a reference to the superclass.
+      // Emit a reference to the superclass. This should be abstract for now,
+      // but transitively completing the class will complete it.
       auto superclass = IGF.emitAbstractTypeMetadataRef(
                           getSuperclassForMetadata(IGM, Target));
 
@@ -6870,7 +6888,7 @@ namespace {
 
     void emitInitializeMetadata(IRGenFunction &IGF, llvm::Value *metadata,
                                 MetadataDependencyCollector *collector) {
-      llvm_unreachable("Not implemented for foreign reference types.");
+      // Foreign reference types do not currently require extra metadata.
     }
 
     // Visitor methods.
@@ -6924,7 +6942,13 @@ namespace {
     }
 
     void addValueWitnessTable() {
-      auto vwtPointer = emitValueWitnessTable(/*relative*/ false).getValue();
+      llvm::Constant* vwtPointer = nullptr;
+      if (auto cd = Target->getClangDecl())
+        if (auto rd = dyn_cast<clang::RecordDecl>(cd))
+          if (rd->isAnonymousStructOrUnion())
+            vwtPointer = llvm::Constant::getNullValue(IGM.WitnessTablePtrTy);
+      if (!vwtPointer)
+        vwtPointer = emitValueWitnessTable(/*relative*/ false).getValue();
       B.addSignedPointer(vwtPointer,
                          IGM.getOptions().PointerAuth.ValueWitnessTable,
                          PointerAuthEntity());
@@ -7846,8 +7870,10 @@ irgen::emitExtendedExistentialTypeShape(IRGenModule &IGM,
 
     // You can have a superclass with a generic parameter pack in a composition,
     // like `C<each T> & P<Int>`
-    assert(genHeader->GenericPackArguments.empty() &&
+    if (genSig) {
+      assert(genHeader->GenericPackArguments.empty() &&
            "Generic parameter packs not supported here yet");
+    }
 
     return b.finishAndCreateFuture();
   }, [&](llvm::GlobalVariable *var) {
diff --git a/lib/IRGen/GenObjC.cpp b/lib/IRGen/GenObjC.cpp
index 0dd45be382692..5693f54f9d98d 100644
--- a/lib/IRGen/GenObjC.cpp
+++ b/lib/IRGen/GenObjC.cpp
@@ -661,6 +661,7 @@ namespace {
       case SILDeclRef::Kind::EnumElement:
       case SILDeclRef::Kind::GlobalAccessor:
       case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
+      case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
       case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
       case SILDeclRef::Kind::EntryPoint:
       case SILDeclRef::Kind::AsyncEntryPoint:
@@ -830,8 +831,7 @@ Callee irgen::getObjCMethodCallee(IRGenFunction &IGF,
     }
   }();
 
-  messenger = llvm::ConstantExpr::getBitCast(messenger,
-                                             sig.getType()->getPointerTo());
+  messenger = llvm::ConstantExpr::getBitCast(messenger, IGF.IGM.PtrTy);
 
   // super.constructor references an instance method (even though the
   // decl is really a 'static' member). Similarly, destructors refer
@@ -877,7 +877,7 @@ llvm::Value *irgen::emitObjCAllocObjectCall(IRGenFunction &IGF,
 
   if (self->getType() != IGF.IGM.ObjCClassPtrTy) {
     fnType = llvm::FunctionType::get(self->getType(), self->getType(), false);
-    fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
+    fn = llvm::ConstantExpr::getBitCast(fn, IGF.IGM.PtrTy);
   }
 
   auto call = IGF.Builder.CreateCall(fnType, fn, self);
@@ -935,6 +935,8 @@ static llvm::Function *emitObjCPartialApplicationForwarder(IRGenModule &IGM,
     case ResultConvention::Owned:
     case ResultConvention::Autoreleased:
     case ResultConvention::Pack:
+    case ResultConvention::GuaranteedAddress:
+    case ResultConvention::Guaranteed:
       lifetimeExtendsSelf = false;
       break;
     }
@@ -1316,7 +1318,8 @@ static llvm::Constant *getObjCEncodingForTypes(IRGenModule &IGM,
   encodingString += llvm::itostr(parmOffset);
   encodingString += fixedParamsString;
   encodingString += paramsString;
-  return IGM.getAddrOfGlobalString(encodingString);
+  return IGM.getAddrOfGlobalString(encodingString,
+                                   CStringSectionType::ObjCMethodType);
 }
 
 static llvm::Constant *
@@ -1327,16 +1330,19 @@ getObjectEncodingFromClangNode(IRGenModule &IGM, Decl *d,
     auto clangDecl = d->getClangNode().castAsDecl();
     auto &clangASTContext = IGM.getClangASTContext();
     std::string typeStr;
+    CStringSectionType sectionType;
     if (auto objcMethodDecl = dyn_cast<clang::ObjCMethodDecl>(clangDecl)) {
       typeStr = clangASTContext.getObjCEncodingForMethodDecl(
           objcMethodDecl, useExtendedEncoding /*extended*/);
+      sectionType = CStringSectionType::ObjCMethodType;
     }
     if (auto objcPropertyDecl = dyn_cast<clang::ObjCPropertyDecl>(clangDecl)) {
       typeStr = clangASTContext.getObjCEncodingForPropertyDecl(objcPropertyDecl,
                                                                nullptr);
+      sectionType = CStringSectionType::ObjCPropertyName;
     }
     if (!typeStr.empty()) {
-      return IGM.getAddrOfGlobalString(typeStr.c_str());
+      return IGM.getAddrOfGlobalString(typeStr.c_str(), sectionType);
     }
   }
   return nullptr;
@@ -1432,7 +1438,8 @@ irgen::emitObjCGetterDescriptorParts(IRGenModule &IGM, VarDecl *property) {
   TypeStr += llvm::itostr(ParmOffset);
   TypeStr += "@0:";
   TypeStr += llvm::itostr(PtrSize.getValue());
-  descriptor.typeEncoding = IGM.getAddrOfGlobalString(TypeStr.c_str());
+  descriptor.typeEncoding = IGM.getAddrOfGlobalString(
+      TypeStr.c_str(), CStringSectionType::ObjCMethodType);
   descriptor.silFunction = nullptr;
   descriptor.impl = getObjCGetterPointer(IGM, property, descriptor.silFunction);
   return descriptor;
@@ -1509,7 +1516,8 @@ irgen::emitObjCSetterDescriptorParts(IRGenModule &IGM,
   ParmOffset = 2 * PtrSize.getValue();
   clangASTContext.getObjCEncodingForType(clangType, TypeStr);
   TypeStr += llvm::itostr(ParmOffset);
-  descriptor.typeEncoding = IGM.getAddrOfGlobalString(TypeStr.c_str());
+  descriptor.typeEncoding = IGM.getAddrOfGlobalString(
+      TypeStr.c_str(), CStringSectionType::ObjCMethodType);
   descriptor.silFunction = nullptr;
   descriptor.impl = getObjCSetterPointer(IGM, property, descriptor.silFunction);
   return descriptor;
@@ -1615,7 +1623,8 @@ void irgen::emitObjCIVarInitDestroyDescriptor(IRGenModule &IGM,
   auto ptrSize = IGM.getPointerSize().getValue();
   llvm::SmallString<8> signature;
   signature = "v" + llvm::itostr(ptrSize * 2) + "@0:" + llvm::itostr(ptrSize);
-  descriptor.typeEncoding = IGM.getAddrOfGlobalString(signature);
+  descriptor.typeEncoding =
+      IGM.getAddrOfGlobalString(signature, CStringSectionType::ObjCMethodType);
 
   /// The third element is the method implementation pointer.
   descriptor.impl = llvm::ConstantExpr::getBitCast(objcImpl, IGM.Int8PtrTy);
@@ -1701,7 +1710,7 @@ llvm::Value *IRGenFunction::emitBlockCopyCall(llvm::Value *value) {
 
   if (value->getType() != IGM.ObjCBlockPtrTy) {
     fnType = llvm::FunctionType::get(value->getType(), value->getType(), false);
-    fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
+    fn = llvm::ConstantExpr::getBitCast(fn, IGM.PtrTy);
   }
 
   auto call = Builder.CreateCall(fnType, fn, value);
@@ -1714,7 +1723,7 @@ void IRGenFunction::emitBlockRelease(llvm::Value *value) {
   auto fnType = IGM.getBlockReleaseFnType();
   if (value->getType() != IGM.ObjCBlockPtrTy) {
     fnType = llvm::FunctionType::get(IGM.VoidTy, value->getType(), false);
-    fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
+    fn = llvm::ConstantExpr::getBitCast(fn, IGM.PtrTy);
   }
   auto call = Builder.CreateCall(fnType, fn, value);
   call->setDoesNotThrow();
@@ -1722,6 +1731,11 @@ void IRGenFunction::emitBlockRelease(llvm::Value *value) {
 
 void IRGenFunction::emitForeignReferenceTypeLifetimeOperation(
     ValueDecl *fn, llvm::Value *value, bool needsNullCheck) {
+  if (auto originalDecl = fn->getASTContext()
+                              .getClangModuleLoader()
+                              ->getOriginalForClonedMember(fn))
+    fn = originalDecl;
+
   assert(fn->getClangDecl() && isa<clang::FunctionDecl>(fn->getClangDecl()));
 
   auto clangFn = cast<clang::FunctionDecl>(fn->getClangDecl());
diff --git a/lib/IRGen/GenOpaque.cpp b/lib/IRGen/GenOpaque.cpp
index 5bb471da73b4a..761168483d2cb 100644
--- a/lib/IRGen/GenOpaque.cpp
+++ b/lib/IRGen/GenOpaque.cpp
@@ -72,7 +72,7 @@ static llvm::Type *createWitnessType(IRGenModule &IGM, ValueWitness index) {
 
   // T *(*initializeBufferWithCopyOfBuffer)(B *dest, B *src, M *self);
   case ValueWitness::InitializeBufferWithCopyOfBuffer: {
-    llvm::Type *bufPtrTy = IGM.getFixedBufferTy()->getPointerTo(0);
+    auto *bufPtrTy = IGM.PtrTy;
     llvm::Type *args[] = { bufPtrTy, bufPtrTy, IGM.TypeMetadataPtrTy };
     return llvm::FunctionType::get(IGM.OpaquePtrTy, args, /*isVarArg*/ false);
   }
@@ -293,21 +293,20 @@ getOrCreateValueWitnessTableTy(IRGenModule &IGM, llvm::StructType *&cache,
   return structTy;
 }
 
+llvm::PointerType *
+IRGenModule::getOpaquePointerType(unsigned AddressSpace) const {
+  return llvm::PointerType::get(getLLVMContext(), AddressSpace);
+}
+
 llvm::StructType *IRGenModule::getValueWitnessTableTy() {
   return getOrCreateValueWitnessTableTy(*this, ValueWitnessTableTy,
                                         "swift.vwtable", false);
 }
-llvm::PointerType *IRGenModule::getValueWitnessTablePtrTy() {
-  return getValueWitnessTableTy()->getPointerTo();
-}
 
 llvm::StructType *IRGenModule::getEnumValueWitnessTableTy() {
   return getOrCreateValueWitnessTableTy(*this, EnumValueWitnessTableTy,
                                         "swift.enum_vwtable", true);
 }
-llvm::PointerType *IRGenModule::getEnumValueWitnessTablePtrTy() {
-  return getEnumValueWitnessTableTy()->getPointerTo();
-}
 
 Address irgen::slotForLoadOfOpaqueWitness(IRGenFunction &IGF,
                                           llvm::Value *table,
@@ -455,8 +454,7 @@ static FunctionPointer emitLoadOfValueWitnessFunction(IRGenFunction &IGF,
   auto label = getValueWitnessLabel(index);
   auto signature = IGF.IGM.getValueWitnessSignature(index);
 
-  auto type = signature.getType()->getPointerTo();
-  witness = IGF.Builder.CreateBitCast(witness, type, label);
+  witness = IGF.Builder.CreateBitCast(witness, IGF.IGM.PtrTy, label);
 
   auto authInfo = PointerAuthInfo::emit(IGF,
                                     IGF.getOptions().PointerAuth.ValueWitnesses,
@@ -831,7 +829,7 @@ void irgen::emitDestroyArrayCall(IRGenFunction &IGF,
                                  Address object,
                                  llvm::Value *count) {
   // If T is a trivial/POD type, nothing needs to be done.
-  if (IGF.IGM.getTypeLowering(T).isTrivial())
+  if (IGF.IGM.getTypeProperties(T).isTrivial())
     return;
 
   auto metadata = IGF.emitTypeMetadataRefForLayout(T);
@@ -1120,7 +1118,7 @@ void irgen::emitDestroyCall(IRGenFunction &IGF,
                             SILType T,
                             Address object) {
   // If T is a trivial/POD type, nothing needs to be done.
-  if (IGF.IGM.getTypeLowering(T).isTrivial())
+  if (IGF.IGM.getTypeProperties(T).isTrivial())
     return;
   llvm::Value *metadata;
   auto fn = IGF.emitValueWitnessFunctionRef(T, metadata,
@@ -1168,10 +1166,9 @@ static llvm::Constant *getAllocateValueBufferFunction(IRGenModule &IGM) {
           auto valueAddr =
               IGF.emitAllocRawCall(size, alignMask, "outline.ValueBuffer");
           IGF.Builder.CreateStore(
-              valueAddr, Address(IGF.Builder.CreateBitCast(
-                                     buffer.getAddress(),
-                                     valueAddr->getType()->getPointerTo()),
-                                 IGM.Int8PtrTy, Alignment(1)));
+              valueAddr,
+              Address(IGF.Builder.CreateBitCast(buffer.getAddress(), IGM.PtrTy),
+                      IGM.Int8PtrTy, Alignment(1)));
           addressOutline =
               IGF.Builder.CreateBitCast(valueAddr, IGM.OpaquePtrTy);
           IGF.Builder.CreateBr(doneBB);
@@ -1190,7 +1187,7 @@ Address irgen::emitAllocateValueInBuffer(IRGenFunction &IGF, SILType type,
                                          Address buffer) {
   // Handle FixedSize types.
   auto &IGM = IGF.IGM;
-  auto storagePtrTy = IGM.getStoragePointerType(type);
+  auto *storagePtrTy = IGM.PtrTy;
   auto storageTy = IGM.getStorageType(type);
   auto &Builder = IGF.Builder;
   if (auto *fixedTI = dyn_cast<FixedTypeInfo>(&IGF.getTypeInfo(type))) {
@@ -1261,8 +1258,7 @@ static llvm::Constant *getProjectValueInBufferFunction(IRGenModule &IGM) {
         Builder.emitBlock(outlineBB);
         {
           addressOutline = Builder.CreateLoad(
-              Address(Builder.CreateBitCast(buffer.getAddress(),
-                                            IGM.OpaquePtrTy->getPointerTo()),
+              Address(Builder.CreateBitCast(buffer.getAddress(), IGM.PtrTy),
                       IGM.OpaquePtrTy, Alignment(1)));
           Builder.CreateBr(doneBB);
         }
@@ -1281,7 +1277,7 @@ Address irgen::emitProjectValueInBuffer(IRGenFunction &IGF, SILType type,
                                         Address buffer) {
   // Handle FixedSize types.
   auto &IGM = IGF.IGM;
-  auto storagePtrTy = IGM.getStoragePointerType(type);
+  auto *storagePtrTy = IGM.PtrTy;
   auto storageTy = IGM.getStorageType(type);
   auto &Builder = IGF.Builder;
   if (auto *fixedTI = dyn_cast<FixedTypeInfo>(&IGF.getTypeInfo(type))) {
@@ -1296,8 +1292,7 @@ Address irgen::emitProjectValueInBuffer(IRGenFunction &IGF, SILType type,
     // Outline representation.
     assert(packing == FixedPacking::Allocate && "Expect non dynamic packing");
     auto valueAddr = Builder.CreateLoad(
-        Address(Builder.CreateBitCast(buffer.getAddress(),
-                                      storagePtrTy->getPointerTo()),
+        Address(Builder.CreateBitCast(buffer.getAddress(), IGM.PtrTy),
                 storagePtrTy, buffer.getAlignment()));
     return Address(Builder.CreateBitCast(valueAddr, storagePtrTy), storageTy,
                    buffer.getAlignment());
@@ -1388,8 +1383,7 @@ irgen::getOrCreateGetExtraInhabitantTagFunction(IRGenModule &IGM,
                                         MetadataState::Complete);
 
   // Form a well-typed address from the opaque pointer.
-  ptr = IGF.Builder.CreateBitCast(ptr,
-                                  objectTI.getStorageType()->getPointerTo());
+  ptr = IGF.Builder.CreateBitCast(ptr, IGM.PtrTy);
   Address addr = objectTI.getAddressForPointer(ptr);
 
   auto tag = emitter(IGF, addr, xiCount);
@@ -1473,8 +1467,7 @@ irgen::getOrCreateStoreExtraInhabitantTagFunction(IRGenModule &IGM,
                                         MetadataState::Complete);
 
   // Form a well-typed address from the opaque pointer.
-  ptr = IGF.Builder.CreateBitCast(ptr,
-                                  objectTI.getStorageType()->getPointerTo());
+  ptr = IGF.Builder.CreateBitCast(ptr, IGM.PtrTy);
   Address addr = objectTI.getAddressForPointer(ptr);
 
   emitter(IGF, addr, tag, xiCount);
diff --git a/lib/IRGen/GenPack.cpp b/lib/IRGen/GenPack.cpp
index eb193c4e10e38..9ffca6d8ca07c 100644
--- a/lib/IRGen/GenPack.cpp
+++ b/lib/IRGen/GenPack.cpp
@@ -519,8 +519,7 @@ irgen::emitTypeMetadataPackRef(IRGenFunction &IGF, CanPackType packType,
   std::tie(pack, shape) = emitTypeMetadataPack(IGF, packType, request);
 
   auto *metadata = pack.getAddress().getAddress();
-  metadata = IGF.Builder.CreatePointerCast(
-      metadata, IGF.IGM.TypeMetadataPtrTy->getPointerTo());
+  metadata = IGF.Builder.CreatePointerCast(metadata, IGF.IGM.PtrTy);
 
   if (!IGF.canStackPromotePackMetadata()) {
     metadata = IGF.Builder.CreateCall(
@@ -754,8 +753,7 @@ llvm::Value *irgen::emitWitnessTablePackRef(IRGenFunction &IGF,
   std::tie(pack, shape) = emitWitnessTablePack(IGF, packType, conformance);
 
   auto *result = pack.getAddress().getAddress();
-  result = IGF.Builder.CreatePointerCast(
-      result, IGF.IGM.WitnessTablePtrTy->getPointerTo());
+  result = IGF.Builder.CreatePointerCast(result, IGF.IGM.PtrTy);
 
   if (!IGF.canStackPromotePackMetadata()) {
     result = IGF.Builder.CreateCall(
@@ -1052,7 +1050,7 @@ llvm::Value *irgen::emitTypeMetadataPackElementRef(
 void irgen::bindOpenedElementArchetypesAtIndex(IRGenFunction &IGF,
                                                GenericEnvironment *environment,
                                                llvm::Value *index) {
-  assert(environment->getKind() == GenericEnvironment::Kind::OpenedElement);
+  ASSERT(environment->getKind() == GenericEnvironment::Kind::Element);
 
   // Record the generic type parameters of interest.
   llvm::SmallPtrSet<CanType, 2> openablePackParams;
@@ -1156,8 +1154,7 @@ Address irgen::emitStorageAddressOfPackElement(IRGenFunction &IGF, Address pack,
   assert(elementType.isAddress() && "direct packs not currently supported");
   auto elementSize = getPackElementSize(IGF.IGM, packType);
   auto elementAddress = IGF.Builder.CreateArrayGEP(pack, index, elementSize);
-  return IGF.Builder.CreateElementBitCast(elementAddress,
-                                 IGF.IGM.getStoragePointerType(elementType));
+  return IGF.Builder.CreateElementBitCast(elementAddress, IGF.IGM.PtrTy);
 }
 
 Size irgen::getPackElementSize(IRGenModule &IGM, CanSILPackType ty) {
diff --git a/lib/IRGen/GenPointerAuth.cpp b/lib/IRGen/GenPointerAuth.cpp
index 050d2b7a242ee..b28db161be422 100644
--- a/lib/IRGen/GenPointerAuth.cpp
+++ b/lib/IRGen/GenPointerAuth.cpp
@@ -26,6 +26,7 @@
 #include "swift/SIL/TypeLowering.h"
 #include "clang/CodeGen/CodeGenABITypes.h"
 #include "llvm/ADT/APInt.h"
+#include "llvm/Support/SipHash.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace swift;
@@ -160,7 +161,7 @@ struct IRGenModule::PointerAuthCachesType {
   llvm::DenseMap<SILDeclRef, llvm::ConstantInt*> Decls;
   llvm::DenseMap<CanType, llvm::ConstantInt*> Types;
   llvm::DenseMap<CanType, llvm::ConstantInt*> YieldTypes;
-  llvm::DenseMap<AssociatedType, llvm::ConstantInt*> AssociatedTypes;
+  llvm::DenseMap<AssociatedTypeDecl *, llvm::ConstantInt*> AssociatedTypes;
   llvm::DenseMap<AssociatedConformance, llvm::ConstantInt*> AssociatedConformances;
 };
 
@@ -324,21 +325,15 @@ PointerAuthInfo::getOtherDiscriminator(IRGenModule &IGM,
   llvm_unreachable("bad kind");
 }
 
-static llvm::ConstantInt *getDiscriminatorForHash(IRGenModule &IGM,
-                                                  uint64_t rawHash) {
-  uint16_t reducedHash = (rawHash % 0xFFFF) + 1;
-  return llvm::ConstantInt::get(IGM.Int64Ty, reducedHash);
-}
-
 static llvm::ConstantInt *getDiscriminatorForString(IRGenModule &IGM,
                                                     StringRef string) {
-  uint64_t rawHash = clang::CodeGen::computeStableStringHash(string);
-  return getDiscriminatorForHash(IGM, rawHash);
+  return llvm::ConstantInt::get(IGM.Int64Ty,
+                                llvm::getPointerAuthStableSipHash(string));
 }
 
-static std::string mangle(AssociatedType association) {
-  return IRGenMangler(association.getAssociation()->getASTContext())
-    .mangleAssociatedTypeAccessFunctionDiscriminator(association);
+static std::string mangle(AssociatedTypeDecl *assocType) {
+  return IRGenMangler(assocType->getASTContext())
+    .mangleAssociatedTypeAccessFunctionDiscriminator(assocType);
 }
 
 static std::string mangle(const AssociatedConformance &association) {
@@ -430,7 +425,7 @@ PointerAuthEntity::getDeclDiscriminator(IRGenModule &IGM) const {
   }
 
   case Kind::AssociatedType: {
-    auto association = Storage.get<AssociatedType>(StoredKind);
+    auto association = Storage.get<AssociatedTypeDecl *>(StoredKind);
     llvm::ConstantInt *&cache =
       IGM.getPointerAuthCaches().AssociatedTypes[association];
     if (cache) return cache;
@@ -570,7 +565,8 @@ static void hashStringForFunctionType(IRGenModule &IGM, CanSILFunctionType type,
   }
 }
 
-static uint64_t getTypeHash(IRGenModule &IGM, CanSILFunctionType type) {
+static llvm::ConstantInt *getTypeDiscriminator(IRGenModule &IGM,
+                                               CanSILFunctionType type) {
   // The hash we need to do here ignores:
   //   - thickness, so that we can promote thin-to-thick without rehashing;
   //   - error results, so that we can promote nonthrowing-to-throwing
@@ -590,10 +586,11 @@ static uint64_t getTypeHash(IRGenModule &IGM, CanSILFunctionType type) {
   hashStringForFunctionType(
       IGM, type, Out,
       genericSig.getCanonicalSignature().getGenericEnvironment());
-  return clang::CodeGen::computeStableStringHash(Out.str());
+  return getDiscriminatorForString(IGM, Out.str());
 }
 
-static uint64_t getYieldTypesHash(IRGenModule &IGM, CanSILFunctionType type) {
+static llvm::ConstantInt *
+getCoroutineYieldTypesDiscriminator(IRGenModule &IGM, CanSILFunctionType type) {
   SmallString<32> buffer;
   llvm::raw_svector_ostream out(buffer);
   auto genericSig = type->getInvocationGenericSignature();
@@ -629,7 +626,7 @@ static uint64_t getYieldTypesHash(IRGenModule &IGM, CanSILFunctionType type) {
     out << ":";
   }
 
-  return clang::CodeGen::computeStableStringHash(out.str());  
+  return getDiscriminatorForString(IGM, out.str());
 }
 
 llvm::ConstantInt *
@@ -649,8 +646,7 @@ PointerAuthEntity::getTypeDiscriminator(IRGenModule &IGM) const {
       llvm::ConstantInt *&cache = IGM.getPointerAuthCaches().Types[fnType];
       if (cache) return cache;
 
-      auto hash = getTypeHash(IGM, fnType);
-      cache = getDiscriminatorForHash(IGM, hash);
+      cache = ::getTypeDiscriminator(IGM, fnType);
       return cache;
     }
     
@@ -667,15 +663,6 @@ PointerAuthEntity::getTypeDiscriminator(IRGenModule &IGM) const {
     llvm_unreachable("invalid representation");
   };
 
-  auto getCoroutineYieldTypesDiscriminator = [&](CanSILFunctionType fnType) {
-    llvm::ConstantInt *&cache = IGM.getPointerAuthCaches().Types[fnType];
-    if (cache) return cache;
-
-    auto hash = getYieldTypesHash(IGM, fnType);
-    cache = getDiscriminatorForHash(IGM, hash);
-    return cache;
-  };
-
   switch (StoredKind) {
   case Kind::None:
   case Kind::Special:
@@ -687,7 +674,13 @@ PointerAuthEntity::getTypeDiscriminator(IRGenModule &IGM) const {
 
   case Kind::CoroutineYieldTypes: {
     auto fnType = Storage.get<CanSILFunctionType>(StoredKind);
-    return getCoroutineYieldTypesDiscriminator(fnType);
+
+    llvm::ConstantInt *&cache = IGM.getPointerAuthCaches().Types[fnType];
+    if (cache)
+      return cache;
+
+    cache = getCoroutineYieldTypesDiscriminator(IGM, fnType);
+    return cache;
   }
 
   case Kind::CanSILFunctionType: {
diff --git a/lib/IRGen/GenPointerAuth.h b/lib/IRGen/GenPointerAuth.h
index 0d9c0e86bd2aa..2473f57365aca 100644
--- a/lib/IRGen/GenPointerAuth.h
+++ b/lib/IRGen/GenPointerAuth.h
@@ -86,7 +86,7 @@ class PointerAuthEntity {
   using Members = ExternalUnionMembers<void,
                                        Special,
                                        ValueWitness,
-                                       AssociatedType,
+                                       AssociatedTypeDecl *,
                                        AssociatedConformance,
                                        CanSILFunctionType,
                                        SILDeclRef,
@@ -105,7 +105,7 @@ class PointerAuthEntity {
     case Kind::SILDeclRef:
       return Members::indexOf<SILDeclRef>();
     case Kind::AssociatedType:
-      return Members::indexOf<AssociatedType>();
+      return Members::indexOf<AssociatedTypeDecl *>();
     case Kind::AssociatedConformance:
       return Members::indexOf<AssociatedConformance>();
     case Kind::SILFunction:
@@ -139,9 +139,9 @@ class PointerAuthEntity {
     assert(isValueWitnessFunction(witness));
     Storage.emplace<ValueWitness>(StoredKind, witness);
   }
-  PointerAuthEntity(AssociatedType association)
+  PointerAuthEntity(AssociatedTypeDecl *assocType)
       : StoredKind(Kind::AssociatedType) {
-    Storage.emplaceAggregate<AssociatedType>(StoredKind, association);
+    Storage.emplaceAggregate<AssociatedTypeDecl *>(StoredKind, assocType);
   }
   PointerAuthEntity(const AssociatedConformance &association)
       : StoredKind(Kind::AssociatedConformance) {
diff --git a/lib/IRGen/GenProto.cpp b/lib/IRGen/GenProto.cpp
index b7ad6e6dd6e8c..96b2960d37fae 100644
--- a/lib/IRGen/GenProto.cpp
+++ b/lib/IRGen/GenProto.cpp
@@ -28,7 +28,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/AST/ASTContext.h"
-#include "swift/AST/CanTypeVisitor.h"
 #include "swift/AST/Types.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
@@ -163,6 +162,8 @@ class PolymorphicConvention {
                              CanType type, Args... args);
   bool considerType(CanType type, IsExact_t isExact,
                     unsigned sourceIndex, MetadataPath &&path);
+  bool considerTupleType(CanTupleType type, IsExact_t isExact,
+                         unsigned sourceIndex, MetadataPath &&path);
 
   /// Testify to generic parameters in the Self type of a protocol
   /// witness method.
@@ -354,6 +355,15 @@ bool PolymorphicConvention::considerType(CanType type, IsExact_t isExact,
                                          std::move(path), callbacks);
 }
 
+bool PolymorphicConvention::considerTupleType(CanTupleType type, IsExact_t isExact,
+                                              unsigned sourceIndex,
+                                              MetadataPath &&path) {
+  FulfillmentMapCallback callbacks(*this);
+  return Fulfillments.searchTupleTypeMetadata(IGM, type, isExact,
+                                              MetadataState::Complete, sourceIndex,
+                                              std::move(path), callbacks);
+}
+
 void PolymorphicConvention::considerWitnessSelf(CanSILFunctionType fnType) {
   CanType selfTy = fnType->getSelfInstanceType(
       IGM.getSILModule(), IGM.getMaximalTypeExpansionContext());
@@ -362,13 +372,17 @@ void PolymorphicConvention::considerWitnessSelf(CanSILFunctionType fnType) {
   // First, bind type metadata for Self.
   Sources.emplace_back(MetadataSource::Kind::SelfMetadata, selfTy);
 
-  if (selfTy->is<GenericTypeParamType>()) {
-    // The Self type is abstract, so we can fulfill its metadata from
-    // the Self metadata parameter.
-    addSelfMetadataFulfillment(selfTy);
-  }
+  if (auto tupleTy = dyn_cast<TupleType>(selfTy)) {
+    considerTupleType(tupleTy, IsInexact, Sources.size() - 1, MetadataPath());
+  } else {
+    if (isa<GenericTypeParamType>(selfTy)) {
+      // The Self type is abstract, so we can fulfill its metadata from
+      // the Self metadata parameter.
+      addSelfMetadataFulfillment(selfTy);
+    }
 
-  considerType(selfTy, IsInexact, Sources.size() - 1, MetadataPath());
+    considerType(selfTy, IsInexact, Sources.size() - 1, MetadataPath());
+  }
 
   // The witness table for the Self : P conformance can be
   // fulfilled from the Self witness table parameter.
@@ -946,11 +960,11 @@ namespace {
       }
     }
 
-    void addAssociatedType(AssociatedType requirement) {
+    void addAssociatedType(AssociatedTypeDecl *assocType) {
       // In Embedded Swift witness tables don't have associated-types entries.
-      if (requirement.getAssociation()->getASTContext().LangOpts.hasFeature(Feature::Embedded))
+      if (assocType->getASTContext().LangOpts.hasFeature(Feature::Embedded))
         return;
-      Entries.push_back(WitnessTableEntry::forAssociatedType(requirement));
+      Entries.push_back(WitnessTableEntry::forAssociatedType(assocType));
     }
 
     void addAssociatedConformance(const AssociatedConformance &req) {
@@ -1266,6 +1280,9 @@ static llvm::Value *emitWitnessTableAccessorCall(
 
   // Emit the source metadata if we haven't yet.
   if (!*srcMetadataCache) {
+    // Witness table accesses only require abstract type metadata; this
+    // is so that we can create the witness tables without introducing
+    // cycle problems.
     *srcMetadataCache = IGF.emitAbstractTypeMetadataRef(conformingType);
   }
 
@@ -1330,8 +1347,8 @@ mapConformanceIntoContext(const RootProtocolConformance *conf) {
 
 WitnessIndex ProtocolInfo::getAssociatedTypeIndex(
                                     IRGenModule &IGM,
-                                    AssociatedType assocType) const {
-  assert(!IGM.isResilient(assocType.getSourceProtocol(),
+                                    AssociatedTypeDecl *assocType) const {
+  assert(!IGM.isResilient(assocType->getProtocol(),
                           ResilienceExpansion::Maximal) &&
          "Cannot ask for the associated type index of non-resilient protocol");
   for (auto &witness : getWitnessEntries()) {
@@ -1387,9 +1404,9 @@ class DirectConformanceInfo : public ConformanceInfo {
 class SpecializedConformanceInfo : public ConformanceInfo {
   friend ProtocolInfo;
 
-  const SpecializedProtocolConformance *Conformance;
+  const ProtocolConformance *Conformance;
 public:
-  SpecializedConformanceInfo(const SpecializedProtocolConformance *C)
+  SpecializedConformanceInfo(const ProtocolConformance *C)
       : Conformance(C) {}
 
   llvm::Value *getTable(IRGenFunction &IGF,
@@ -1468,12 +1485,10 @@ class AccessorConformanceInfo : public ConformanceInfo {
 
     void defineAssociatedTypeWitnessTableAccessFunction(
                                         AssociatedConformance requirement,
-                                        CanType associatedType,
                                         ProtocolConformanceRef conformance);
 
     llvm::Constant *getAssociatedConformanceWitness(
                                     AssociatedConformance requirement,
-                                    CanType associatedType,
                                     ProtocolConformanceRef conformance);
 
     const FulfillmentMap &getFulfillmentMap() {
@@ -1524,8 +1539,7 @@ class AccessorConformanceInfo : public ConformanceInfo {
       SpecializedBaseConformances;
 
     ArrayRef<SILWitnessTable::Entry> SILEntries;
-    ArrayRef<SILWitnessTable::ConditionalConformance>
-        SILConditionalConformances;
+    ArrayRef<ProtocolConformanceRef> SILConditionalConformances;
 
     const ProtocolInfo &PI;
 
@@ -1680,7 +1694,7 @@ class AccessorConformanceInfo : public ConformanceInfo {
               IGM.FunctionPtrTy);
         } else if (isCalleeAllocatedCoroutineRequirement) {
           witness = llvm::ConstantExpr::getBitCast(
-              IGM.getDeletedCalleeAllocatedCoroutineMethodErrorAsyncFunctionPointer(),
+              IGM.getDeletedCalleeAllocatedCoroutineMethodErrorCoroFunctionPointer(),
               IGM.CoroFunctionPointerPtrTy);
         } else {
           witness = llvm::ConstantExpr::getBitCast(
@@ -1709,7 +1723,7 @@ class AccessorConformanceInfo : public ConformanceInfo {
       llvm_unreachable("cannot emit a witness table with placeholders in it");
     }
 
-    void addAssociatedType(AssociatedType requirement) {
+    void addAssociatedType(AssociatedTypeDecl *assocType) {
       auto &entry = SILEntries.front();
       SILEntries = SILEntries.slice(1);
 
@@ -1720,10 +1734,9 @@ class AccessorConformanceInfo : public ConformanceInfo {
 #ifndef NDEBUG
       assert(entry.getKind() == SILWitnessTable::AssociatedType
              && "sil witness table does not match protocol");
-      assert(entry.getAssociatedTypeWitness().Requirement
-             == requirement.getAssociation()
+      assert(entry.getAssociatedTypeWitness().Requirement == assocType
              && "sil witness table does not match protocol");
-      auto piIndex = PI.getAssociatedTypeIndex(IGM, requirement);
+      auto piIndex = PI.getAssociatedTypeIndex(IGM, assocType);
       assert((size_t)piIndex.getValue() ==
              Table.size() - WitnessTableFirstRequirementOffset &&
              "offset doesn't match ProtocolInfo layout");
@@ -1731,23 +1744,22 @@ class AccessorConformanceInfo : public ConformanceInfo {
       (void)entry;
 #endif
 
-      auto associate =
-          Conformance.getTypeWitness(requirement.getAssociation());
-      llvm::Constant *witness =
+      auto typeWitness = Conformance.getTypeWitness(assocType);
+      llvm::Constant *typeWitnessAddr =
           IGM.getAssociatedTypeWitness(
-            associate,
+            typeWitness,
             Conformance.getDeclContext()->getGenericSignatureOfContext(),
             /*inProtocolContext=*/false);
-      witness = llvm::ConstantExpr::getBitCast(witness, IGM.Int8PtrTy);
+      typeWitnessAddr = llvm::ConstantExpr::getBitCast(typeWitnessAddr, IGM.Int8PtrTy);
 
       if (isRelative) {
-        Table.addRelativeAddress(witness);
+        Table.addRelativeAddress(typeWitnessAddr);
         return;
       }
 
       auto &schema = IGM.getOptions().PointerAuth
                         .ProtocolAssociatedTypeAccessFunctions;
-      Table.addSignedPointer(witness, schema, requirement);
+      Table.addSignedPointer(typeWitnessAddr, schema, assocType);
     }
 
     void addAssociatedConformance(AssociatedConformance requirement) {
@@ -1765,10 +1777,6 @@ class AccessorConformanceInfo : public ConformanceInfo {
         return;
       }
 
-      auto associate =
-        ConformanceInContext.getAssociatedType(
-          requirement.getAssociation())->getCanonicalType();
-
       ProtocolConformanceRef associatedConformance =
         ConformanceInContext.getAssociatedConformance(
           requirement.getAssociation(),
@@ -1802,8 +1810,7 @@ class AccessorConformanceInfo : public ConformanceInfo {
       }
 
       llvm::Constant *witnessEntry =
-        getAssociatedConformanceWitness(requirement, associate,
-                                        associatedConformance);
+        getAssociatedConformanceWitness(requirement, associatedConformance);
 
       if (isRelative) {
         Table.addRelativeAddress(witnessEntry);
@@ -1869,10 +1876,8 @@ static void buildAssociatedTypeValueName(CanType depAssociatedType,
 
 llvm::Constant *WitnessTableBuilderBase::getAssociatedConformanceWitness(
                                 AssociatedConformance requirement,
-                                CanType associatedType,
                                 ProtocolConformanceRef conformance) {
-  defineAssociatedTypeWitnessTableAccessFunction(requirement, associatedType,
-                                                 conformance);
+  defineAssociatedTypeWitnessTableAccessFunction(requirement, conformance);
   assert(isa<NormalProtocolConformance>(Conformance) && "has associated type");
   auto conf = cast<NormalProtocolConformance>(&Conformance);
   return IGM.getMangledAssociatedConformance(conf, requirement);
@@ -1880,8 +1885,8 @@ llvm::Constant *WitnessTableBuilderBase::getAssociatedConformanceWitness(
 
 void WitnessTableBuilderBase::defineAssociatedTypeWitnessTableAccessFunction(
                                 AssociatedConformance requirement,
-                                CanType associatedType,
                                 ProtocolConformanceRef associatedConformance) {
+  auto associatedType = associatedConformance.getType()->getCanonicalType();
   bool hasArchetype = associatedType->hasArchetype();
   bool isOpaqueArchetype = isa<OpaqueTypeArchetypeType>(associatedType);
 
@@ -1926,8 +1931,6 @@ void WitnessTableBuilderBase::defineAssociatedTypeWitnessTableAccessFunction(
   const ConformanceInfo *conformanceI = nullptr;
 
   if (associatedConformance.isConcrete()) {
-    assert(associatedType->isEqual(associatedConformance.getConcrete()->getType()));
-
     conformanceI = &IGM.getConformanceInfo(associatedProtocol,
                                            associatedConformance.getConcrete());
 
@@ -2023,10 +2026,6 @@ void ResilientWitnessTableBuilder::collectResilientWitnesses(
     if (entry.getKind() == SILWitnessTable::AssociatedConformance) {
       const auto &witness = entry.getAssociatedConformanceWitness();
 
-      auto associate =
-        ConformanceInContext.getAssociatedType(
-          witness.Requirement)->getCanonicalType();
-
       ProtocolConformanceRef associatedConformance =
         ConformanceInContext.getAssociatedConformance(witness.Requirement,
                                                       witness.Witness.getProtocol());
@@ -2036,8 +2035,7 @@ void ResilientWitnessTableBuilder::collectResilientWitnesses(
                                         witness.Witness.getProtocol());
 
       llvm::Constant *witnessEntry =
-        getAssociatedConformanceWitness(requirement, associate,
-                                        associatedConformance);
+        getAssociatedConformanceWitness(requirement, associatedConformance);
       resilientWitnesses.push_back(witnessEntry);
       continue;
     }
@@ -2052,8 +2050,7 @@ void ResilientWitnessTableBuilder::collectResilientWitnesses(
       ProtocolConformanceRef inheritedConformance =
         ConformanceInContext.getAssociatedConformance(selfType, baseProto);
       llvm::Constant *witnessEntry =
-        getAssociatedConformanceWitness(requirement, ConcreteType,
-                                        inheritedConformance);
+        getAssociatedConformanceWitness(requirement, inheritedConformance);
       resilientWitnesses.push_back(witnessEntry);
       continue;
     }
@@ -2126,10 +2123,10 @@ llvm::Function *FragileWitnessTableBuilder::buildInstantiationFunction() {
     const auto &condConformance = SILConditionalConformances[idx];
     CanType reqTypeInContext =
       Conformance.getDeclContext()
-        ->mapTypeIntoContext(condConformance.Requirement)
+        ->mapTypeIntoContext(condConformance.getType())
         ->getCanonicalType();
     if (auto archetype = dyn_cast<ArchetypeType>(reqTypeInContext)) {
-      auto condProto = condConformance.Conformance.getProtocol();
+      auto condProto = condConformance.getProtocol();
       IGF.setUnscopedLocalTypeData(
              archetype,
              LocalTypeDataKind::forAbstractProtocolWitnessTable(condProto),
@@ -2245,7 +2242,6 @@ namespace {
         Flags = Flags.withIsSynthesizedNonUnique(conf->isSynthesizedNonUnique());
         Flags = Flags.withIsConformanceOfProtocol(conf->isConformanceOfProtocol());
         Flags = Flags.withHasGlobalActorIsolation(isolation.isGlobalActor());
-        Flags = withSerialExecutorCheckingModeFlags(Flags, conf);
       } else {
         Flags = Flags.withIsRetroactive(false)
                      .withIsSynthesizedNonUnique(false);
@@ -2368,12 +2364,6 @@ namespace {
               LinkEntity::forBaseConformanceDescriptor(requirement));
           B.addRelativeAddress(baseConformanceDescriptor);
         } else if (entry.getKind() == SILWitnessTable::Method) {
-          // distributed thunks don't need resilience
-          if (entry.getMethodWitness().Requirement.isDistributedThunk()) {
-            witnesses = witnesses.drop_back();
-            continue;
-          }
-
           // Method descriptor.
           auto declRef = entry.getMethodWitness().Requirement;
           auto requirement =
@@ -2468,31 +2458,6 @@ namespace {
       B.addRelativeAddress(globalActorConformanceDescriptor);
     }
 
-    static ConformanceFlags
-    withSerialExecutorCheckingModeFlags(ConformanceFlags Flags, const NormalProtocolConformance *conf) {
-      ProtocolDecl *proto = conf->getProtocol();
-      auto &C = proto->getASTContext();
-
-      ConformanceFlags UpdatedFlags = Flags;
-      if (proto->isSpecificProtocol(swift::KnownProtocolKind::SerialExecutor)) {
-        conf->forEachValueWitness([&](const ValueDecl *req,
-                                      Witness witness) {
-          bool nameMatch = witness.getDecl()->getBaseIdentifier() == C.Id_isIsolatingCurrentContext;
-          if (nameMatch) {
-            if (DeclContext *NominalOrExtension = witness.getDecl()->getDeclContext()) {
-              // If the witness is NOT the default implementation in the _Concurrency library,
-              // we should record that this is an user provided implementation and we should call it.
-              bool hasNonDefaultIsIsolatingCurrentContext =
-                  !NominalOrExtension->getParentModule()->isConcurrencyModule();
-              UpdatedFlags = UpdatedFlags.withHasNonDefaultSerialExecutorIsIsolatingCurrentContext(
-                            hasNonDefaultIsIsolatingCurrentContext);
-            }
-          }
-        });
-      }
-
-      return UpdatedFlags;
-    }
   };
 }
 
@@ -2628,8 +2593,15 @@ IRGenModule::getConformanceInfo(const ProtocolDecl *protocol,
   const ConformanceInfo *info;
 
   auto *specConf = conformance;
-  if (auto *inheritedC = dyn_cast<InheritedProtocolConformance>(conformance))
+  if (auto *inheritedC = dyn_cast<InheritedProtocolConformance>(conformance)) {
+    SILWitnessTable *wt = getSILModule().lookUpWitnessTable(inheritedC);
+    if (wt && wt->getConformance() == inheritedC) {
+      info = new SpecializedConformanceInfo(inheritedC);
+      Conformances.try_emplace(conformance, info);
+      return *info;
+    }
     specConf = inheritedC->getInheritedConformance();
+  }
 
   // If there is a specialized SILWitnessTable for the specialized conformance,
   // directly use it.
@@ -3410,16 +3382,15 @@ MetadataResponse MetadataPath::followComponent(IRGenFunction &IGF,
     assert(entry.isOutOfLineBase());
     auto inheritedProtocol = entry.getBase();
 
-    sourceKey.Kind =
-      LocalTypeDataKind::forAbstractProtocolWitnessTable(inheritedProtocol);
     if (sourceKey.Kind.isConcreteProtocolConformance()) {
       auto inheritedConformance =
         sourceKey.Kind.getConcreteProtocolConformance()
           ->getInheritedConformance(inheritedProtocol);
-      if (inheritedConformance) {
-        sourceKey.Kind = LocalTypeDataKind::forConcreteProtocolWitnessTable(
-                                                          inheritedConformance);
-      }
+      sourceKey.Kind = LocalTypeDataKind::forConcreteProtocolWitnessTable(
+                                                        inheritedConformance);
+    } else {
+      sourceKey.Kind =
+        LocalTypeDataKind::forAbstractProtocolWitnessTable(inheritedProtocol);
     }
 
     if (!source) return MetadataResponse();
@@ -3448,14 +3419,12 @@ MetadataResponse MetadataPath::followComponent(IRGenFunction &IGF,
     auto association = entry.getAssociatedConformancePath();
     auto associatedRequirement = entry.getAssociatedConformanceRequirement();
 
-    CanType associatedType =
-      sourceConformance.getAssociatedType(sourceType, association)
-        ->getCanonicalType();
-    sourceKey.Type = associatedType;
 
     auto associatedConformance =
-      sourceConformance.getAssociatedConformance(sourceType, association,
-                                                 associatedRequirement);
+      sourceConformance.getAssociatedConformance(association, associatedRequirement);
+    auto associatedType = associatedConformance.getType()->getCanonicalType();
+
+    sourceKey.Type = associatedType;
     sourceKey.Kind =
       LocalTypeDataKind::forProtocolWitnessTable(associatedConformance);
 
@@ -3478,6 +3447,7 @@ MetadataResponse MetadataPath::followComponent(IRGenFunction &IGF,
       return MetadataResponse::forComplete(associatedWTable);
     }
 
+    // Witness table lookups only require abstract metadata.
     auto *sourceMetadata =
         IGF.emitAbstractTypeMetadataRef(sourceType);
 
@@ -3528,10 +3498,11 @@ MetadataResponse MetadataPath::followComponent(IRGenFunction &IGF,
       // type directly.
       auto depMemType = cast<DependentMemberType>(association);
       CanType baseSubstType =
-        sourceConformance.getAssociatedType(sourceType, depMemType.getBase())
-          ->getCanonicalType();
+        depMemType.getBase().subst(
+          SubstitutionMap::getProtocolSubstitutions(sourceConformance))
+            ->getCanonicalType();
       if (auto archetypeType = dyn_cast<ArchetypeType>(baseSubstType)) {
-        AssociatedType baseAssocType(depMemType->getAssocType());
+        auto *baseAssocType = depMemType->getAssocType();
 
         MetadataResponse response =
           emitAssociatedTypeMetadataRef(IGF, archetypeType, baseAssocType,
@@ -3544,6 +3515,7 @@ MetadataResponse MetadataPath::followComponent(IRGenFunction &IGF,
         associatedMetadata = response.getMetadata();
       } else {
         // Ok, fall back to realizing the (possibly concrete) type.
+        // Witness table lookups only require abstract metadata.
         associatedMetadata =
           IGF.emitAbstractTypeMetadataRef(sourceKey.Type);
       }
@@ -4445,7 +4417,7 @@ static FunctionPointer emitRelativeProtocolWitnessTableAccess(IRGenFunction &IGF
     helperFn->getFunctionType(), helperFn, {wtable});
   call->setCallingConv(IGF.IGM.DefaultCC);
   call->setDoesNotThrow();
-  auto fn = IGF.Builder.CreateBitCast(call, signature.getType()->getPointerTo());
+  auto fn = IGF.Builder.CreateBitCast(call, IGM.PtrTy);
   return FunctionPointer::createUnsigned(fnType, fn, signature, true);
 }
 
@@ -4475,8 +4447,7 @@ FunctionPointer irgen::emitWitnessMethodValue(IRGenFunction &IGF,
   auto fnType = IGF.IGM.getSILTypes().getConstantFunctionType(
       IGF.IGM.getMaximalTypeExpansionContext(), member);
   Signature signature = IGF.IGM.getSignature(fnType);
-  witnessFnPtr = IGF.Builder.CreateBitCast(witnessFnPtr,
-                                           signature.getType()->getPointerTo());
+  witnessFnPtr = IGF.Builder.CreateBitCast(witnessFnPtr, IGF.IGM.PtrTy);
 
   auto &schema = fnType->isAsync()
                      ? IGF.getOptions().PointerAuth.AsyncProtocolWitnesses
@@ -4556,18 +4527,18 @@ MetadataResponse
 irgen::emitAssociatedTypeMetadataRef(IRGenFunction &IGF,
                                      llvm::Value *parentMetadata,
                                      llvm::Value *wtable,
-                                     AssociatedType associatedType,
+                                     AssociatedTypeDecl *assocType,
                                      DynamicMetadataRequest request) {
   auto &IGM = IGF.IGM;
 
   // Extract the requirements base descriptor.
   auto reqBaseDescriptor =
     IGM.getAddrOfProtocolRequirementsBaseDescriptor(
-                                          associatedType.getSourceProtocol());
+                                          assocType->getProtocol());
 
   // Extract the associated type descriptor.
   auto assocTypeDescriptor =
-    IGM.getAddrOfAssociatedTypeDescriptor(associatedType.getAssociation());
+    IGM.getAddrOfAssociatedTypeDescriptor(assocType);
   // Call swift_getAssociatedTypeWitness().
   auto call =
     IGF.IGM.IRGen.Opts.UseRelativeProtocolWitnessTables ?
diff --git a/lib/IRGen/GenProto.h b/lib/IRGen/GenProto.h
index 8904550f52e98..c67343de0d800 100644
--- a/lib/IRGen/GenProto.h
+++ b/lib/IRGen/GenProto.h
@@ -29,7 +29,7 @@ namespace llvm {
 
 namespace swift {
   class AssociatedConformance;
-  class AssociatedType;
+  class AssociatedTypeDecl;
   class CanType;
   class FuncDecl;
   enum class MetadataState : size_t;
@@ -90,11 +90,11 @@ namespace irgen {
   ///
   /// \param parentMetadata - the type metadata for T
   /// \param wtable - the witness table witnessing the conformance of T to P
-  /// \param associatedType - the declaration of X; a member of P
+  /// \param assocType - the declaration of X; a member of P
   MetadataResponse emitAssociatedTypeMetadataRef(IRGenFunction &IGF,
                                                  llvm::Value *parentMetadata,
                                                  llvm::Value *wtable,
-                                                 AssociatedType associatedType,
+                                                 AssociatedTypeDecl *assocType,
                                                  DynamicMetadataRequest request);
 
   // Return the offset one should do on a witness table pointer to retrieve the
diff --git a/lib/IRGen/GenRecord.h b/lib/IRGen/GenRecord.h
index eaee3f2f94894..2aaf5df5c879c 100644
--- a/lib/IRGen/GenRecord.h
+++ b/lib/IRGen/GenRecord.h
@@ -138,7 +138,7 @@ class RecordTypeInfoImpl : public Base,
         NumFields(fields.size()),
         AreFieldsABIAccessible(fieldsABIAccessible) {
     std::uninitialized_copy(fields.begin(), fields.end(),
-                            this->template getTrailingObjects<FieldImpl>());
+                            this->getTrailingObjects());
   }
 
   void fillWithZerosIfSensitive(IRGenFunction &IGF, Address address, SILType T) const {
@@ -157,12 +157,19 @@ class RecordTypeInfoImpl : public Base,
     return new(buffer) Impl(fields, std::forward<As>(args)...);
   }
 
+  void operator delete(void *ptr) {
+    const auto *pThis = static_cast<RecordTypeInfoImpl *>(ptr);
+    const size_t count = pThis->NumFields;
+    const size_t size = Impl::template totalSizeToAlloc<FieldImpl>(count);
+    ::operator delete(ptr, size);
+  }
+
   bool areFieldsABIAccessible() const {
     return AreFieldsABIAccessible;
   }
 
   ArrayRef<FieldImpl> getFields() const {
-    return {this->template getTrailingObjects<FieldImpl>(), NumFields};
+    return this->getTrailingObjects(NumFields);
   }
 
   /// The standard schema is just all the fields jumbled together.
diff --git a/lib/IRGen/GenReflection.cpp b/lib/IRGen/GenReflection.cpp
index c111180ff7e16..848731fe1088e 100644
--- a/lib/IRGen/GenReflection.cpp
+++ b/lib/IRGen/GenReflection.cpp
@@ -177,6 +177,25 @@ class PrintMetadataSource
   }
 };
 
+/// Determine whether the given generic nominal that involves inverse
+/// requirements (e.g., Optional, Span) is always available for demangling
+/// purposes.
+static bool nominalIsAlwaysAvailableForDemangling(const NominalTypeDecl *nom) {
+  // Only consider standard library types for this.
+  if (!nom->getModuleContext()->isStdlibModule())
+    return false;
+
+  // If there's an @_originallyDefined(in:) attribute, then the nominal is
+  // not always available for demangling.
+  for (auto attr: nom->getAttrs().getAttributes<OriginallyDefinedInAttr>()) {
+    if (!attr->isInvalid() && attr->isActivePlatform(nom->getASTContext()))
+      return false;
+  }
+
+  // Everything else is available.
+  return true;
+}
+
 std::optional<llvm::VersionTuple>
 getRuntimeVersionThatSupportsDemanglingType(CanType type) {
   enum VersionRequirement {
@@ -185,9 +204,10 @@ getRuntimeVersionThatSupportsDemanglingType(CanType type) {
     Swift_5_5,
     Swift_6_0,
     Swift_6_1,
+    Swift_6_2,
 
     // Short-circuit if we find this requirement.
-    Latest = Swift_6_1
+    Latest = Swift_6_2
   };
 
   VersionRequirement latestRequirement = None;
@@ -204,6 +224,11 @@ getRuntimeVersionThatSupportsDemanglingType(CanType type) {
       auto isolation = fn->getIsolation();
       auto sendingResult = fn->hasSendingResult();
 
+      // The mangling for nonisolated(nonsending) function types was introduced
+      // in Swift 6.2.
+      if (isolation.isNonIsolatedCaller())
+        return addRequirement(Swift_6_2);
+
       // The Swift 6.1 runtime fixes a bug preventing successful demangling
       // when @isolated(any) or global actor isolation is combined with a
       // sending result.
@@ -246,16 +271,16 @@ getRuntimeVersionThatSupportsDemanglingType(CanType type) {
     /// signature uses NoncopyableGenerics. Since inverses are mangled into
     /// symbols, a Swift 6.0+ runtime is generally needed to demangle them.
     ///
-    /// We make an exception for types in the stdlib, like Optional, since the
-    /// runtime should still be able to demangle them, based on the availability
-    /// of the type.
+    /// We make an exception for some types in the stdlib, like Optional, since
+    /// the runtime should still be able to demangle them, based on the
+    /// availability of the type.
     if (auto nominalTy = dyn_cast<NominalOrBoundGenericNominalType>(t)) {
       auto *nom = nominalTy->getDecl();
       if (auto sig = nom->getGenericSignature()) {
         SmallVector<InverseRequirement, 2> inverses;
         SmallVector<Requirement, 2> reqs;
         sig->getRequirementsWithInverses(reqs, inverses);
-        if (!inverses.empty() && !nom->getModuleContext()->isStdlibModule()) {
+        if (!inverses.empty() && !nominalIsAlwaysAvailableForDemangling(nom)) {
           return addRequirement(Swift_6_0);
         }
       }
@@ -271,6 +296,7 @@ getRuntimeVersionThatSupportsDemanglingType(CanType type) {
   });
 
   switch (latestRequirement) {
+  case Swift_6_2: return llvm::VersionTuple(6, 2);
   case Swift_6_1: return llvm::VersionTuple(6, 1);
   case Swift_6_0: return llvm::VersionTuple(6, 0);
   case Swift_5_5: return llvm::VersionTuple(5, 5);
@@ -289,13 +315,12 @@ getRuntimeVersionThatSupportsDemanglingType(CanType type) {
 // where completing the metadata during demangling might cause cyclic
 // dependencies.
 static std::pair<llvm::Constant *, unsigned>
-getTypeRefByFunction(IRGenModule &IGM,
-                     CanGenericSignature sig,
-                     CanType t) {
+getTypeRefByFunction(IRGenModule &IGM, CanGenericSignature sig, CanType t,
+                     MangledTypeRefRole role) {
   IRGenMangler mangler(IGM.Context);
   std::string symbolName =
     mangler.mangleSymbolNameForMangledMetadataAccessorString(
-                                                   "get_type_metadata", sig, t);
+                                                   "get_type_metadata", sig, t, role);
   auto constant = IGM.getAddrOfStringForMetadataRef(symbolName, /*align*/2,
                                                     /*low bit*/false,
     [&](ConstantInitBuilder &B) {
@@ -326,9 +351,22 @@ getTypeRefByFunction(IRGenModule &IGM,
           ? genericEnv->mapTypeIntoContext(t)->getCanonicalType()
           : t;
 
-        // If a type is noncopyable, lie about the resolved type unless the
-        // runtime is sufficiently aware of noncopyable types.
-        if (substT->isNoncopyable()) {
+        // If a type is noncopyable, lie about the resolved type to reflection
+        // APIs unless the runtime is sufficiently aware of noncopyable types.
+        bool shouldHideNoncopyableTypeFromOldRuntimes;
+        switch (role) {
+        case MangledTypeRefRole::Metadata:
+        case MangledTypeRefRole::DefaultAssociatedTypeWitness:
+        case MangledTypeRefRole::FlatUnique:
+          shouldHideNoncopyableTypeFromOldRuntimes = false;
+          break;
+        case MangledTypeRefRole::FieldMetadata:
+        case MangledTypeRefRole::Reflection:
+          shouldHideNoncopyableTypeFromOldRuntimes = true;
+          break;
+        }
+        if (shouldHideNoncopyableTypeFromOldRuntimes
+            && substT->isNoncopyable()) {
           // Darwin-based platforms have ABI stability, and we want binaries
           // that use noncopyable types nongenerically today to be forward
           // compatible with a future OS runtime that supports noncopyable
@@ -407,7 +445,11 @@ getTypeRefByFunction(IRGenModule &IGM,
       // Form the mangled name with its relative reference.
       auto S = B.beginStruct();
       S.setPacked(true);
-      S.add(llvm::ConstantInt::get(IGM.Int8Ty, 255));
+      if (role == MangledTypeRefRole::DefaultAssociatedTypeWitness) {
+        S.add(llvm::ConstantInt::get(
+            IGM.Int8Ty,
+            ProtocolRequirementFlags::AssociatedTypeInProtocolContextByte));
+      }
       S.add(llvm::ConstantInt::get(IGM.Int8Ty, 9));
       S.addCompactFunctionReference(accessor);
 
@@ -487,7 +529,7 @@ getTypeRefImpl(IRGenModule &IGM,
     // the field will be artificially hidden to reflectors.
     if (isAlwaysNoncopyable) {
       IGM.IRGen.noteUseOfTypeMetadata(type);
-      return getTypeRefByFunction(IGM, sig, type);
+      return getTypeRefByFunction(IGM, sig, type, role);
     }
   }
   LLVM_FALLTHROUGH;
@@ -498,12 +540,12 @@ getTypeRefImpl(IRGenModule &IGM,
     // ensuring that we can always reconstruct type metadata from a mangled name
     // in-process.
     IGM.IRGen.noteUseOfTypeMetadata(type);
-    
+
     // If the minimum deployment target's runtime demangler wouldn't understand
     // this mangled name, then fall back to generating a "mangled name" with a
     // symbolic reference with a callback function.
     if (mangledNameIsUnknownToDeployTarget(IGM, type)) {
-      return getTypeRefByFunction(IGM, sig, type);
+      return getTypeRefByFunction(IGM, sig, type, role);
     }
 
     break;
@@ -602,7 +644,7 @@ IRGenModule::emitWitnessTableRefString(CanType type,
             type = genericEnv->mapTypeIntoContext(type)->getCanonicalType();
           }
           if (origType->hasTypeParameter()) {
-            conformance = conformance.subst(origType,
+            conformance = conformance.subst(
                 genericEnv->getForwardingSubstitutionMap());
           }
           auto ret = emitWitnessTableRef(IGF, type, conformance);
@@ -946,35 +988,13 @@ class FieldTypeMetadataBuilder : public ReflectionMetadataBuilder {
     B.addInt16(uint16_t(kind));
     B.addInt16(FieldRecordSize);
 
-    // Filter to select which fields we'll export FieldDescriptors for.
-    auto exportable_field =
-      [](Field field) {
-        // Don't export private C++ fields that were imported as private Swift fields.
-        // The type of a private field might not have all the type witness
-        // operations that Swift requires, for instance,
-        // `std::unique_ptr<IncompleteType>` would not have a destructor.
-        if (field.getKind() == Field::Kind::Var &&
-            field.getVarDecl()->getClangDecl() &&
-            field.getVarDecl()->getFormalAccess() == AccessLevel::Private)
-          return false;
-        // All other fields are exportable
-        return true;
-      };
-
-    // Count exportable fields
-    int exportableFieldCount = 0;
-    forEachField(IGM, NTD, [&](Field field) {
-      if (exportable_field(field)) {
-        ++exportableFieldCount;
-      }
-    });
-
     // Emit exportable fields, prefixed with a count
-    B.addInt32(exportableFieldCount);
+    B.addInt32(countExportableFields(IGM, NTD));
+
+    // Filter to select which fields we'll export FieldDescriptor for.
     forEachField(IGM, NTD, [&](Field field) {
-      if (exportable_field(field)) {
+      if (isExportableField(field))
         addField(field);
-      }
     });
   }
 
@@ -1689,6 +1709,9 @@ llvm::Constant *IRGenModule::getAddrOfFieldName(StringRef Name) {
 llvm::Constant *
 IRGenModule::getAddrOfBoxDescriptor(SILType BoxedType,
                                     CanGenericSignature genericSig) {
+  if (BoxedType.hasLocalArchetype())
+    return llvm::Constant::getNullValue(CaptureDescriptorPtrTy);
+
   if (IRGen.Opts.ReflectionMetadata != ReflectionMetadataMode::Runtime)
     return llvm::Constant::getNullValue(CaptureDescriptorPtrTy);
 
diff --git a/lib/IRGen/GenStruct.cpp b/lib/IRGen/GenStruct.cpp
index f6b6647cfc6aa..d870143d153ea 100644
--- a/lib/IRGen/GenStruct.cpp
+++ b/lib/IRGen/GenStruct.cpp
@@ -16,15 +16,18 @@
 
 #include "GenStruct.h"
 
+#include "IRGen.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/IRGenOptions.h"
 #include "swift/AST/Pattern.h"
+#include "swift/AST/ReferenceCounting.h"
 #include "swift/AST/SemanticAttrs.h"
 #include "swift/AST/SubstitutionMap.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/ClangImporter/ClangImporter.h"
 #include "swift/IRGen/Linking.h"
 #include "swift/SIL/SILFunctionBuilder.h"
 #include "swift/SIL/SILModule.h"
@@ -42,6 +45,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
+#include "llvm/Support/Error.h"
 #include <iterator>
 
 #include "GenDecl.h"
@@ -340,8 +344,7 @@ namespace {
               IGF.IGM.Int8Ty, metadataBytes,
               IGF.IGM.getSize(scanner.FieldOffset - scanner.AddressPoint));
           fieldOffsetPtr =
-            IGF.Builder.CreateBitCast(fieldOffsetPtr,
-                                      IGF.IGM.Int32Ty->getPointerTo());
+              IGF.Builder.CreateBitCast(fieldOffsetPtr, IGF.IGM.PtrTy);
           llvm::Value *fieldOffset = IGF.Builder.CreateLoad(
               Address(fieldOffsetPtr, IGF.IGM.Int32Ty, Alignment(4)));
           fieldOffset = IGF.Builder.CreateZExtOrBitCast(fieldOffset,
@@ -367,20 +370,23 @@ namespace {
       : public StructTypeInfoBase<LoadableClangRecordTypeInfo, LoadableTypeInfo,
                                   ClangFieldInfo> {
     const clang::RecordDecl *ClangDecl;
+    bool HasReferenceField;
 
   public:
     LoadableClangRecordTypeInfo(ArrayRef<ClangFieldInfo> fields,
                                 unsigned explosionSize, llvm::Type *storageType,
                                 Size size, SpareBitVector &&spareBits,
                                 Alignment align,
-                                const clang::RecordDecl *clangDecl)
+                                IsTriviallyDestroyable_t isTriviallyDestroyable,
+                                IsCopyable_t isCopyable,
+                                const clang::RecordDecl *clangDecl,
+                                bool hasReferenceField)
         : StructTypeInfoBase(StructTypeInfoKind::LoadableClangRecordTypeInfo,
                              fields, explosionSize, FieldsAreABIAccessible,
                              storageType, size, std::move(spareBits), align,
-                             IsTriviallyDestroyable,
-                             IsCopyable,
-                             IsFixedSize, IsABIAccessible),
-          ClangDecl(clangDecl) {}
+                             isTriviallyDestroyable, isCopyable, IsFixedSize,
+                             IsABIAccessible),
+          ClangDecl(clangDecl), HasReferenceField(hasReferenceField) {}
 
     TypeLayoutEntry
     *buildTypeLayoutEntry(IRGenModule &IGM,
@@ -444,6 +450,7 @@ namespace {
                                    const ClangFieldInfo &field) const {
       llvm_unreachable("non-fixed field in Clang type?");
     }
+    bool hasReferenceField() const { return HasReferenceField; }
   };
 
   class AddressOnlyPointerAuthRecordTypeInfo final
@@ -468,6 +475,7 @@ namespace {
     AddressOnlyPointerAuthRecordTypeInfo(ArrayRef<ClangFieldInfo> fields,
                                          llvm::Type *storageType, Size size,
                                          Alignment align,
+                                         IsCopyable_t isCopyable,
                                          const clang::RecordDecl *clangDecl)
         : StructTypeInfoBase(StructTypeInfoKind::AddressOnlyClangRecordTypeInfo,
                              fields, FieldsAreABIAccessible, storageType, size,
@@ -476,7 +484,7 @@ namespace {
                              SpareBitVector(std::optional<APInt>{
                                  llvm::APInt(size.getValueInBits(), 0)}),
                              align, IsNotTriviallyDestroyable,
-                             IsNotBitwiseTakable, IsCopyable, IsFixedSize,
+                             IsNotBitwiseTakable, isCopyable, IsFixedSize,
                              IsABIAccessible),
           clangDecl(clangDecl) {
       (void)clangDecl;
@@ -549,7 +557,8 @@ namespace {
         if (ctor->isCopyConstructor() &&
             // FIXME: Support default arguments (rdar://142414553)
             ctor->getNumParams() == 1 &&
-            ctor->getAccess() == clang::AS_public && !ctor->isDeleted())
+            ctor->getAccess() == clang::AS_public && !ctor->isDeleted() &&
+            !ctor->isIneligibleOrNotSelected())
           return ctor;
       }
       return nullptr;
@@ -563,7 +572,8 @@ namespace {
         if (ctor->isMoveConstructor() &&
             // FIXME: Support default arguments (rdar://142414553)
             ctor->getNumParams() == 1 &&
-            ctor->getAccess() == clang::AS_public && !ctor->isDeleted())
+            ctor->getAccess() == clang::AS_public && !ctor->isDeleted() &&
+            !ctor->isIneligibleOrNotSelected())
           return ctor;
       }
       return nullptr;
@@ -616,8 +626,54 @@ namespace {
       auto fnType = createCXXCopyConstructorFunctionType(IGF, T);
       auto globalDecl =
           clang::GlobalDecl(copyConstructor, clang::Ctor_Complete);
+
+      auto &ctx = IGF.IGM.Context;
+      auto *importer = static_cast<ClangImporter *>(ctx.getClangModuleLoader());
+      
+      auto &diagEngine = importer->getClangSema().getDiagnostics();
+      clang::DiagnosticErrorTrap trap(diagEngine);
       auto clangFnAddr =
           IGF.IGM.getAddrOfClangGlobalDecl(globalDecl, NotForDefinition);
+
+      if (trap.hasErrorOccurred()) {
+        SourceLoc copyConstructorLoc =
+            importer->importSourceLocation(copyConstructor->getLocation());
+        auto *recordDecl = copyConstructor->getParent();
+        ctx.Diags.diagnose(copyConstructorLoc, diag::failed_emit_copy,
+                           recordDecl);
+
+        bool hasCopyableIfAttr =
+            recordDecl->hasAttrs() &&
+            llvm::any_of(recordDecl->getAttrs(), [&](clang::Attr *attr) {
+              if (auto swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr)) {
+                StringRef attrStr = swiftAttr->getAttribute();
+                assert(!attrStr.starts_with("~Copyable") &&
+                       "Trying to emit copy of a type annotated with "
+                       "'SWIFT_NONCOPYABLE'?");
+                if (attrStr.starts_with("copyable_if:"))
+                  return true;
+              }
+              return false;
+            });
+
+        bool hasRequiresClause =
+            !copyConstructor->getTrailingRequiresClause().isNull();
+
+        if (hasRequiresClause || hasCopyableIfAttr) {
+          ctx.Diags.diagnose(copyConstructorLoc, diag::maybe_missing_annotation,
+                             recordDecl);
+          ctx.Diags.diagnose(copyConstructorLoc, diag::maybe_missing_parameter,
+                             hasCopyableIfAttr, recordDecl);
+        } else {
+          ctx.Diags.diagnose(copyConstructorLoc, diag::use_requires_expression);
+          ctx.Diags.diagnose(copyConstructorLoc, diag::annotate_copyable_if);
+        }
+
+        if (!copyConstructor->isUserProvided()) {
+          ctx.Diags.diagnose(copyConstructorLoc, diag::annotate_non_copyable);
+        }
+      }
+
       auto callee = cast<llvm::Function>(clangFnAddr->stripPointerCasts());
       Signature signature = IGF.IGM.getSignature(fnType, copyConstructor);
       std::string name = "__swift_cxx_copy_ctor" + callee->getName().str();
@@ -644,6 +700,7 @@ namespace {
     AddressOnlyCXXClangRecordTypeInfo(ArrayRef<ClangFieldInfo> fields,
                                       llvm::Type *storageType, Size size,
                                       Alignment align,
+                                      IsCopyable_t isCopyable,
                                       const clang::RecordDecl *clangDecl)
         : StructTypeInfoBase(StructTypeInfoKind::AddressOnlyClangRecordTypeInfo,
                              fields, FieldsAreABIAccessible, storageType, size,
@@ -653,9 +710,7 @@ namespace {
                                  llvm::APInt(size.getValueInBits(), 0)}),
                              align, IsNotTriviallyDestroyable,
                              IsNotBitwiseTakable,
-                             // TODO: Set this appropriately for the type's
-                             // C++ import behavior.
-                             IsCopyable, IsFixedSize, IsABIAccessible),
+                             isCopyable, IsFixedSize, IsABIAccessible),
           ClangDecl(clangDecl) {
       (void)ClangDecl;
     }
@@ -1316,6 +1371,11 @@ class ClangRecordLowering {
   Size NextOffset = Size(0);
   Size SubobjectAdjustment = Size(0);
   unsigned NextExplosionIndex = 0;
+  // Types that are trivial in C++ but are containing fields to reference types
+  // are not trivial in Swift, they cannot be copied using memcpy as we need to
+  // do the proper retain operations.
+  bool hasReferenceField = false;
+
 public:
   ClangRecordLowering(IRGenModule &IGM, StructDecl *swiftDecl,
                       const clang::RecordDecl *clangDecl,
@@ -1341,15 +1401,27 @@ class ClangRecordLowering {
     llvmType->setBody(LLVMFields, /*packed*/ true);
     if (SwiftType.getStructOrBoundGenericStruct()->isCxxNonTrivial()) {
       return AddressOnlyCXXClangRecordTypeInfo::create(
-          FieldInfos, llvmType, TotalStride, TotalAlignment, ClangDecl);
+          FieldInfos, llvmType, TotalStride, TotalAlignment,
+          (SwiftDecl && !SwiftDecl->canBeCopyable())
+            ? IsNotCopyable : IsCopyable,
+          ClangDecl);
     }
     if (SwiftType.getStructOrBoundGenericStruct()->isNonTrivialPtrAuth()) {
       return AddressOnlyPointerAuthRecordTypeInfo::create(
-          FieldInfos, llvmType, TotalStride, TotalAlignment, ClangDecl);
+          FieldInfos, llvmType, TotalStride, TotalAlignment,
+          (SwiftDecl && !SwiftDecl->canBeCopyable())
+            ? IsNotCopyable : IsCopyable,
+          ClangDecl);
     }
     return LoadableClangRecordTypeInfo::create(
         FieldInfos, NextExplosionIndex, llvmType, TotalStride,
-        std::move(SpareBits), TotalAlignment, ClangDecl);
+        std::move(SpareBits), TotalAlignment,
+        (SwiftDecl &&
+         (SwiftDecl->getValueTypeDestructor() || hasReferenceField))
+            ? IsNotTriviallyDestroyable
+            : IsTriviallyDestroyable,
+        (SwiftDecl && !SwiftDecl->canBeCopyable()) ? IsNotCopyable : IsCopyable,
+        ClangDecl, hasReferenceField);
   }
 
 private:
@@ -1396,7 +1468,7 @@ class ClangRecordLowering {
         // Collect all of the following bitfields.
         unsigned bitStart =
           layout.getFieldOffset(clangField->getFieldIndex());
-        unsigned bitEnd = bitStart + clangField->getBitWidthValue(ClangContext);
+        unsigned bitEnd = bitStart + clangField->getBitWidthValue();
 
         while (cfi != cfe && (*cfi)->isBitField()) {
           clangField = *cfi++;
@@ -1412,7 +1484,7 @@ class ClangRecordLowering {
             bitStart = nextStart;
           }
 
-          bitEnd = nextStart + clangField->getBitWidthValue(ClangContext);
+          bitEnd = nextStart + clangField->getBitWidthValue();
         }
 
         addOpaqueBitField(bitStart, bitEnd);
@@ -1459,6 +1531,14 @@ class ClangRecordLowering {
     unsigned fieldOffset = layout.getFieldOffset(clangField->getFieldIndex());
     assert(!clangField->isBitField());
     Size offset( SubobjectAdjustment.getValue() + fieldOffset / 8);
+    std::optional<clang::CharUnits> dataSize;
+    if (clangField->hasAttr<clang::NoUniqueAddressAttr>()) {
+      if (const auto *rd = clangField->getType()->getAsRecordDecl()) {
+        // Clang can store the next field in the padding of this one.
+        const auto &fieldLayout = ClangContext.getASTRecordLayout(rd);
+        dataSize = fieldLayout.getDataSize();
+      }
+    }
 
     // If we have a Swift import of this type, use our lowered information.
     if (swiftField) {
@@ -1466,11 +1546,24 @@ class ClangRecordLowering {
           SwiftType.getFieldType(swiftField, IGM.getSILModule(),
                                  IGM.getMaximalTypeExpansionContext())));
       addField(swiftField, offset, fieldTI, isZeroSized);
+      auto fieldTy =
+          swiftField->getInterfaceType()->lookThroughSingleOptionalType();
+      if (fieldTy->isAnyClassReferenceType() &&
+          fieldTy->getReferenceCounting() != ReferenceCounting::None)
+        hasReferenceField = true;
+      else if (auto structDecl = fieldTy->getStructOrBoundGenericStruct();
+               structDecl && structDecl->hasClangNode() &&
+               getStructTypeInfoKind(fieldTI) ==
+                   StructTypeInfoKind::LoadableClangRecordTypeInfo)
+        if (fieldTI.as<LoadableClangRecordTypeInfo>().hasReferenceField())
+          hasReferenceField = true;
       return;
     }
 
     // Otherwise, add it as an opaque blob.
-    auto fieldSize = isZeroSized ? clang::CharUnits::Zero() : ClangContext.getTypeSizeInChars(clangField->getType());
+    auto fieldTypeSize = ClangContext.getTypeSizeInChars(clangField->getType());
+    auto fieldSize = isZeroSized ? clang::CharUnits::Zero()
+                                 : dataSize.value_or(fieldTypeSize);
     return addOpaqueField(offset, Size(fieldSize.getQuantity()));
   }
 
@@ -1696,9 +1789,9 @@ const TypeInfo *TypeConverter::convertStructType(TypeBase *key, CanType type,
   // Treat infinitely-sized types as resilient as well, since they can never
   // be concretized.
   if (IGM.isResilient(D, ResilienceExpansion::Maximal)
-      || IGM.getSILTypes().getTypeLowering(SILType::getPrimitiveAddressType(type),
-                                            TypeExpansionContext::minimal())
-            .getRecursiveProperties().isInfinite()) {
+      || IGM.getSILTypes().getTypeProperties(SILType::getPrimitiveAddressType(type),
+                                             TypeExpansionContext::minimal())
+            .isInfinite()) {
     auto copyable = !D->canBeCopyable()
       ? IsNotCopyable : IsCopyable;
     auto structAccessible =
diff --git a/lib/IRGen/GenThunk.cpp b/lib/IRGen/GenThunk.cpp
index d22bf843fb6f0..f0bfd4fa0b2bb 100644
--- a/lib/IRGen/GenThunk.cpp
+++ b/lib/IRGen/GenThunk.cpp
@@ -387,8 +387,7 @@ void IRGenThunk::emit() {
     // unreachable
     auto *continuation = result.claimNext();
     auto sig = Signature::forCoroutineContinuation(IGF.IGM, origTy);
-    continuation =
-        IGF.Builder.CreateBitCast(continuation, sig.getType()->getPointerTo());
+    continuation = IGF.Builder.CreateBitCast(continuation, IGF.IGM.PtrTy);
     auto schemaAndEntity =
         getCoroutineResumeFunctionPointerAuth(IGF.IGM, origTy);
     auto pointerAuth = PointerAuthInfo::emit(
@@ -604,8 +603,7 @@ IRGenModule::getAddrOfAsyncFunctionPointer(LinkEntity entity) {
       llvm::ConstantExpr::getAdd(PointerPointerConstant, Marker);
 
   IndirectAsyncFunctionPointers[entity] = Address;
-  return llvm::ConstantExpr::getIntToPtr(Address,
-                                         AsyncFunctionPointerTy->getPointerTo());
+  return llvm::ConstantExpr::getIntToPtr(Address, PtrTy);
 }
 
 llvm::Constant *
@@ -668,8 +666,7 @@ llvm::Constant *IRGenModule::getAddrOfCoroFunctionPointer(LinkEntity entity) {
       llvm::ConstantExpr::getAdd(PointerPointerConstant, Marker);
 
   IndirectCoroFunctionPointers[entity] = Address;
-  return llvm::ConstantExpr::getIntToPtr(Address,
-                                         CoroFunctionPointerTy->getPointerTo());
+  return llvm::ConstantExpr::getIntToPtr(Address, PtrTy);
 }
 
 llvm::Constant *
@@ -737,10 +734,7 @@ IRGenModule::getAddrOfMethodLookupFunction(ClassDecl *classDecl,
     return entry;
   }
 
-  llvm::Type *params[] = {
-    TypeMetadataPtrTy,
-    MethodDescriptorStructTy->getPointerTo()
-  };
+  llvm::Type *params[] = {TypeMetadataPtrTy, PtrTy};
   auto fnType = llvm::FunctionType::get(Int8PtrTy, params, false);
   Signature signature(fnType, llvm::AttributeList(), SwiftCC);
   LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
diff --git a/lib/IRGen/GenTuple.cpp b/lib/IRGen/GenTuple.cpp
index 92d5368387bb5..6233c36a6c6b2 100644
--- a/lib/IRGen/GenTuple.cpp
+++ b/lib/IRGen/GenTuple.cpp
@@ -646,8 +646,7 @@ Address irgen::projectTupleElementAddressByDynamicIndex(IRGenFunction &IGF,
     result = tupleOffset;
   }
 
-  auto *gep =
-      IGF.emitByteOffsetGEP(tuple.getAddress(), result, IGF.IGM.OpaqueTy);
+  auto *gep = IGF.emitByteOffsetGEP(tuple.getAddress(), result);
   auto elementAddress = Address(gep, IGF.IGM.OpaqueTy,
                                 IGF.IGM.getPointerAlignment());
   return IGF.Builder.CreateElementBitCast(elementAddress,
diff --git a/lib/IRGen/GenType.cpp b/lib/IRGen/GenType.cpp
index 556af360eef8b..d5cb390955fb6 100644
--- a/lib/IRGen/GenType.cpp
+++ b/lib/IRGen/GenType.cpp
@@ -120,7 +120,8 @@ Address TypeInfo::getAddressForPointer(llvm::Value *ptr) const {
 }
 
 Address TypeInfo::getUndefAddress() const {
-  return Address(llvm::UndefValue::get(getStorageType()->getPointerTo(0)),
+  return Address(llvm::UndefValue::get(llvm::PointerType::getUnqual(
+                     getStorageType()->getContext())),
                  getStorageType(), getBestKnownAlignment());
 }
 
@@ -701,16 +702,14 @@ llvm::Value *irgen::getFixedTypeEnumTagSinglePayload(
       // The size of the chunk does not have to be a power of 2.
       auto *caseIndexType =
           llvm::IntegerType::get(Ctx, fixedSize.getValueInBits());
-      auto *caseIndexAddr =
-          Builder.CreateBitCast(valueAddr, caseIndexType->getPointerTo());
+      auto *caseIndexAddr = Builder.CreateBitCast(valueAddr, IGM.PtrTy);
       caseIndexFromValue = Builder.CreateZExtOrTrunc(
           Builder.CreateLoad(
               Address(caseIndexAddr, caseIndexType, Alignment(1))),
           IGM.Int32Ty);
     } else {
       auto *caseIndexType = llvm::IntegerType::get(Ctx, 32);
-      auto *caseIndexAddr =
-          Builder.CreateBitCast(valueAddr, caseIndexType->getPointerTo());
+      auto *caseIndexAddr = Builder.CreateBitCast(valueAddr, IGM.PtrTy);
       caseIndexFromValue = Builder.CreateZExtOrTrunc(
           Builder.CreateLoad(
               Address(caseIndexAddr, caseIndexType, Alignment(1))),
@@ -1902,22 +1901,27 @@ const Lowering::TypeLowering &IRGenModule::getTypeLowering(SILType type) const {
       type, TypeExpansionContext::maximalResilienceExpansionOnly());
 }
 
-bool IRGenModule::isTypeABIAccessible(SILType type) const {
-  return getSILModule().isTypeABIAccessible(
-      type, TypeExpansionContext::maximalResilienceExpansionOnly());
+SILTypeProperties IRGenModule::getTypeProperties(SILType type) const {
+  return getTypeProperties(type,
+             TypeExpansionContext::maximalResilienceExpansionOnly());
 }
 
-/// Get a pointer to the storage type for the given type.  Note that,
-/// unlike fetching the type info and asking it for the storage type,
-/// this operation will succeed for forward-declarations.
-llvm::PointerType *IRGenModule::getStoragePointerType(SILType T) {
-  return getStoragePointerTypeForLowered(T.getASTType());
+SILTypeProperties
+IRGenModule::getTypeProperties(SILType type,
+                               TypeExpansionContext forExpansion) const {
+  return getSILTypes().getTypeProperties(type, forExpansion);
 }
-llvm::PointerType *IRGenModule::getStoragePointerTypeForUnlowered(Type T) {
-  return getStorageTypeForUnlowered(T)->getPointerTo();
+
+SILTypeProperties
+IRGenModule::getTypeProperties(AbstractionPattern origType,
+                               Type substType,
+                               TypeExpansionContext forExpansion) const {
+  return getSILTypes().getTypeProperties(origType, substType, forExpansion);
 }
-llvm::PointerType *IRGenModule::getStoragePointerTypeForLowered(CanType T) {
-  return getStorageTypeForLowered(T)->getPointerTo();
+
+bool IRGenModule::isTypeABIAccessible(SILType type) const {
+  return getSILModule().isTypeABIAccessible(
+      type, TypeExpansionContext::maximalResilienceExpansionOnly());
 }
 
 llvm::Type *IRGenModule::getStorageTypeForUnlowered(Type subst) {
@@ -2010,7 +2014,7 @@ CanType TypeConverter::getExemplarType(CanType contextTy) {
           return getExemplarArchetype(arch);
         return type;
       },
-      MakeAbstractConformanceForGenericType(),
+      LookUpConformanceInModule(),
       SubstFlags::PreservePackExpansionLevel |
       SubstFlags::SubstitutePrimaryArchetypes);
     return CanType(exemplified);
@@ -2378,9 +2382,8 @@ const TypeInfo *TypeConverter::convertType(CanType ty) {
 
 /// Convert an inout type.  This is always just a bare pointer.
 const TypeInfo *TypeConverter::convertInOutType(InOutType *T) {
-  auto referenceType =
-    IGM.getStoragePointerTypeForUnlowered(CanType(T->getObjectType()));
-  
+  auto *referenceType = IGM.PtrTy;
+
   // Just use the reference type as a primitive pointer.
   return createPrimitive(referenceType, IGM.getPointerSize(),
                          IGM.getPointerAlignment());
@@ -2422,7 +2425,8 @@ namespace {
   /// type mismatch) if an aggregate type containing a value of this
   /// type is generated generically rather than independently for
   /// different specializations?
-  class IsIRTypeDependent : public CanTypeVisitor<IsIRTypeDependent, bool> {
+  class IsIRTypeDependent :
+      public CanTypeVisitor_AnyNominal<IsIRTypeDependent, bool> {
     IRGenModule &IGM;
   public:
     IsIRTypeDependent(IRGenModule &IGM) : IGM(IGM) {}
@@ -2436,11 +2440,8 @@ namespace {
 
     // Dependent struct types need their own implementation if any
     // field type might need its own implementation.
-    bool visitStructType(CanStructType type) {
-      return visitStructDecl(type->getDecl());
-    }
-    bool visitBoundGenericStructType(CanBoundGenericStructType type) {
-      return visitStructDecl(type->getDecl());
+    bool visitAnyStructType(CanType type, StructDecl *decl) {
+      return visitStructDecl(decl);
     }
     bool visitStructDecl(StructDecl *decl) {
       if (IGM.isResilient(decl, ResilienceExpansion::Maximal))
@@ -2469,11 +2470,8 @@ namespace {
 
     // Dependent enum types need their own implementation if any
     // element payload type might need its own implementation.
-    bool visitEnumType(CanEnumType type) {
-      return visitEnumDecl(type->getDecl());
-    }
-    bool visitBoundGenericEnumType(CanBoundGenericEnumType type) {
-      return visitEnumDecl(type->getDecl());
+    bool visitAnyEnumType(CanType type, EnumDecl *decl) {
+      return visitEnumDecl(decl);
     }
     bool visitEnumDecl(EnumDecl *decl) {
       if (IGM.isResilient(decl, ResilienceExpansion::Maximal))
@@ -2492,11 +2490,8 @@ namespace {
     }
 
     // Conservatively assume classes need unique implementations.
-    bool visitClassType(CanClassType type) {
-      return visitClassDecl(type->getDecl());
-     }
-    bool visitBoundGenericClassType(CanBoundGenericClassType type) {
-      return visitClassDecl(type->getDecl());
+    bool visitAnyClassType(CanType type, ClassDecl *theClass) {
+      return visitClassDecl(theClass);
     }
     bool visitClassDecl(ClassDecl *theClass) {
       return true;
@@ -3051,7 +3046,7 @@ IsABIAccessible_t irgen::isTypeABIAccessibleIfFixedSize(IRGenModule &IGM,
                                                         CanType ty) {
 
   // Copyable types currently are always ABI-accessible if they're fixed size.
-  if (!ty->isNoncopyable())
+  if (ty->isCopyable())
     return IsABIAccessible;
 
   // Check for a deinit. If this type does not define a deinit it is ABI
diff --git a/lib/IRGen/GenValueWitness.cpp b/lib/IRGen/GenValueWitness.cpp
index ecd9a77f9ded9..4d5ea33ba1b6a 100644
--- a/lib/IRGen/GenValueWitness.cpp
+++ b/lib/IRGen/GenValueWitness.cpp
@@ -237,17 +237,14 @@ static ResultTy emitForDynamicPacking(IRGenFunction &IGF,
 static Address emitDefaultProjectBuffer(IRGenFunction &IGF, Address buffer,
                                         SILType T, const TypeInfo &type,
                                         FixedPacking packing) {
-  llvm::PointerType *resultTy = type.getStorageType()->getPointerTo();
   switch (packing) {
   case FixedPacking::Allocate: {
 
     // Use copy-on-write existentials?
     auto &IGM = IGF.IGM;
     auto &Builder = IGF.Builder;
-    Address boxAddress(
-        Builder.CreateBitCast(buffer.getAddress(),
-                              IGM.RefCountedPtrTy->getPointerTo()),
-        IGM.RefCountedPtrTy, buffer.getAlignment());
+    Address boxAddress(Builder.CreateBitCast(buffer.getAddress(), IGM.PtrTy),
+                       IGM.RefCountedPtrTy, buffer.getAlignment());
     auto *boxStart = IGF.Builder.CreateLoad(boxAddress);
     auto *alignmentMask = type.getAlignmentMask(IGF, T);
     auto *heapHeaderSize = llvm::ConstantInt::get(
@@ -255,10 +252,9 @@ static Address emitDefaultProjectBuffer(IRGenFunction &IGF, Address buffer,
     auto *startOffset =
         Builder.CreateAnd(Builder.CreateAdd(heapHeaderSize, alignmentMask),
                           Builder.CreateNot(alignmentMask));
-    auto *addressInBox =
-        IGF.emitByteOffsetGEP(boxStart, startOffset, IGM.OpaqueTy);
+    auto *addressInBox = IGF.emitByteOffsetGEP(boxStart, startOffset);
 
-    addressInBox = Builder.CreateBitCast(addressInBox, resultTy);
+    addressInBox = Builder.CreateBitCast(addressInBox, IGF.IGM.PtrTy);
     return type.getAddressForPointer(addressInBox);
   }
 
@@ -286,12 +282,11 @@ static Address emitDefaultAllocateBuffer(IRGenFunction &IGF, Address buffer,
     auto *metadata = IGF.emitTypeMetadataRefForLayout(T);
     IGF.emitAllocBoxCall(metadata, box, address);
     IGF.Builder.CreateStore(
-        box, Address(IGF.Builder.CreateBitCast(buffer.getAddress(),
-                                               box->getType()->getPointerTo()),
-                     IGF.IGM.RefCountedPtrTy, buffer.getAlignment()));
+        box,
+        Address(IGF.Builder.CreateBitCast(buffer.getAddress(), IGF.IGM.PtrTy),
+                IGF.IGM.RefCountedPtrTy, buffer.getAlignment()));
 
-    llvm::PointerType *resultTy = type.getStorageType()->getPointerTo();
-    address = IGF.Builder.CreateBitCast(address, resultTy);
+    address = IGF.Builder.CreateBitCast(address, IGF.IGM.PtrTy);
     return type.getAddressForPointer(address);
   }
 
@@ -325,10 +320,10 @@ static Address emitDefaultInitializeBufferWithCopyOfBuffer(
     return destObject;
   } else {
     assert(packing == FixedPacking::Allocate);
-    auto *destReferenceAddr = IGF.Builder.CreateBitCast(
-        destBuffer.getAddress(), IGF.IGM.RefCountedPtrTy->getPointerTo());
-    auto *srcReferenceAddr = IGF.Builder.CreateBitCast(
-        srcBuffer.getAddress(), IGF.IGM.RefCountedPtrTy->getPointerTo());
+    auto *destReferenceAddr =
+        IGF.Builder.CreateBitCast(destBuffer.getAddress(), IGF.IGM.PtrTy);
+    auto *srcReferenceAddr =
+        IGF.Builder.CreateBitCast(srcBuffer.getAddress(), IGF.IGM.PtrTy);
     auto *srcReference = IGF.Builder.CreateLoad(Address(
         srcReferenceAddr, IGF.IGM.RefCountedPtrTy, srcBuffer.getAlignment()));
     IGF.emitNativeStrongRetain(srcReference, IGF.getDefaultAtomicity());
@@ -375,8 +370,7 @@ static Address getArgAs(IRGenFunction &IGF,
                         const TypeInfo &type,
                         StringRef name) {
   llvm::Value *arg = getArg(it, name);
-  llvm::Value *result =
-    IGF.Builder.CreateBitCast(arg, type.getStorageType()->getPointerTo());
+  llvm::Value *result = IGF.Builder.CreateBitCast(arg, IGF.IGM.PtrTy);
   return type.getAddressForPointer(result);
 }
 
@@ -570,8 +564,7 @@ static void buildValueWitnessFunction(IRGenModule &IGM,
     llvm::Value *value = getArg(argv, "value");
     getArgAsLocalSelfTypeMetadata(IGF, argv, abstractType);
 
-    auto enumTy = type.getStorageType()->getPointerTo();
-    value = IGF.Builder.CreateBitCast(value, enumTy);
+    value = IGF.Builder.CreateBitCast(value, IGM.PtrTy);
     auto enumAddr = type.getAddressForPointer(value);
 
     llvm::Value *result;
@@ -612,8 +605,7 @@ static void buildValueWitnessFunction(IRGenModule &IGM,
 
     llvm::Value *value = getArg(argv, "value");
 
-    auto enumTy = type.getStorageType()->getPointerTo();
-    value = IGF.Builder.CreateBitCast(value, enumTy);
+    value = IGF.Builder.CreateBitCast(value, IGM.PtrTy);
 
     llvm::Value *tag = getArg(argv, "tag");
 
@@ -636,8 +628,7 @@ static void buildValueWitnessFunction(IRGenModule &IGM,
 
   case ValueWitness::GetEnumTagSinglePayload: {
     llvm::Value *value = getArg(argv, "value");
-    auto enumTy = type.getStorageType()->getPointerTo();
-    value = IGF.Builder.CreateBitCast(value, enumTy);
+    value = IGF.Builder.CreateBitCast(value, IGM.PtrTy);
 
     llvm::Value *numEmptyCases = getArg(argv, "numEmptyCases");
 
@@ -661,8 +652,7 @@ static void buildValueWitnessFunction(IRGenModule &IGM,
 
   case ValueWitness::StoreEnumTagSinglePayload: {
     llvm::Value *value = getArg(argv, "value");
-    auto enumTy = type.getStorageType()->getPointerTo();
-    value = IGF.Builder.CreateBitCast(value, enumTy);
+    value = IGF.Builder.CreateBitCast(value, IGM.PtrTy);
 
     llvm::Value *whichCase = getArg(argv, "whichCase");
     llvm::Value *numEmptyCases = getArg(argv, "numEmptyCases");
@@ -719,7 +709,7 @@ static llvm::Constant *getNoncopyableTrapFunction(IRGenModule &IGM) {
 /// the second, retains it, loads a pointer from the first, stores the
 /// new pointer in the first, and releases the old pointer.
 static llvm::Constant *getAssignWithCopyStrongFunction(IRGenModule &IGM) {
-  llvm::Type *ptrPtrTy = IGM.RefCountedPtrTy->getPointerTo();
+  auto *ptrPtrTy = IGM.PtrTy;
   llvm::Type *argTys[] = { ptrPtrTy, ptrPtrTy, IGM.WitnessTablePtrTy };
   return IGM.getOrCreateHelperFunction("__swift_assignWithCopy_strong",
                                        ptrPtrTy, argTys,
@@ -743,7 +733,7 @@ static llvm::Constant *getAssignWithCopyStrongFunction(IRGenModule &IGM) {
 /// the second, retains it, loads a pointer from the first, stores the
 /// new pointer in the first, and releases the old pointer.
 static llvm::Constant *getAssignWithTakeStrongFunction(IRGenModule &IGM) {
-  llvm::Type *ptrPtrTy = IGM.RefCountedPtrTy->getPointerTo();
+  auto *ptrPtrTy = IGM.PtrTy;
   llvm::Type *argTys[] = { ptrPtrTy, ptrPtrTy, IGM.WitnessTablePtrTy };
   return IGM.getOrCreateHelperFunction("__swift_assignWithTake_strong",
                                        ptrPtrTy, argTys,
@@ -765,7 +755,7 @@ static llvm::Constant *getAssignWithTakeStrongFunction(IRGenModule &IGM) {
 /// retaining initWithCopy on the first two: it loads a pointer from
 /// the second, retains it, and stores that in the first.
 static llvm::Constant *getInitWithCopyStrongFunction(IRGenModule &IGM) {
-  llvm::Type *ptrPtrTy = IGM.RefCountedPtrTy->getPointerTo();
+  auto *ptrPtrTy = IGM.PtrTy;
   llvm::Type *argTys[] = { ptrPtrTy, ptrPtrTy, IGM.WitnessTablePtrTy };
   return IGM.getOrCreateHelperFunction("__swift_initWithCopy_strong",
                                        ptrPtrTy, argTys,
@@ -837,7 +827,9 @@ struct BoundGenericTypeCharacteristics {
   FixedPacking packing;
 };
 
-ValueWitnessFlags getValueWitnessFlags(const TypeInfo *TI, SILType concreteType,
+ValueWitnessFlags getValueWitnessFlags(IRGenModule &IGM,
+                                       const TypeInfo *TI,
+                                       SILType concreteType,
                                        FixedPacking packing) {
   ValueWitnessFlags flags;
 
@@ -852,6 +844,10 @@ ValueWitnessFlags getValueWitnessFlags(const TypeInfo *TI, SILType concreteType,
     bool isBitwiseBorrowable =
         fixedTI->isBitwiseBorrowable(ResilienceExpansion::Maximal);
     assert(isBitwiseTakable || !isInline);
+    bool isAddressableForDependencies =
+        IGM.getTypeProperties(concreteType, TypeExpansionContext::minimal())
+          .isAddressableForDependencies();
+          
     flags = flags.withAlignment(fixedTI->getFixedAlignment().getValue())
                 .withPOD(fixedTI->isTriviallyDestroyable(ResilienceExpansion::Maximal))
                 .withCopyable(fixedTI->isCopyable(ResilienceExpansion::Maximal))
@@ -864,7 +860,8 @@ ValueWitnessFlags getValueWitnessFlags(const TypeInfo *TI, SILType concreteType,
                 // Swift prior to version 6 didn't have the
                 // IsNotBitwiseBorrowable bit, so to avoid unnecessary variation
                 // in metadata output, we only set the bit when needed.
-                .withBitwiseBorrowable(!isBitwiseTakable || isBitwiseBorrowable);
+                .withBitwiseBorrowable(!isBitwiseTakable || isBitwiseBorrowable)
+                .withAddressableForDependencies(isAddressableForDependencies);
   } else {
     flags = flags.withIncomplete(true);
   }
@@ -1226,11 +1223,13 @@ static void addValueWitness(IRGenModule &IGM, ConstantStructBuilder &B,
   case ValueWitness::Flags: {
     if (boundGenericCharacteristics)
       return B.addInt32(
-          getValueWitnessFlags(boundGenericCharacteristics->TI,
+          getValueWitnessFlags(IGM,
+                               boundGenericCharacteristics->TI,
                                boundGenericCharacteristics->concreteType,
                                boundGenericCharacteristics->packing)
               .getOpaqueValue());
-    return B.addInt32(getValueWitnessFlags(&concreteTI, concreteType, packing)
+    return B.addInt32(getValueWitnessFlags(IGM, &concreteTI,
+                                           concreteType, packing)
                           .getOpaqueValue());
   }
 
@@ -1252,8 +1251,7 @@ static void addValueWitness(IRGenModule &IGM, ConstantStructBuilder &B,
       if (auto *enumDecl = boundGenericCharacteristics->concreteType
                                .getEnumOrBoundGenericEnum())
         if (IGM.getMetadataLayout(enumDecl).hasPayloadSizeOffset())
-          return B.add(llvm::ConstantExpr::getBitCast(
-              IGM.getGetMultiPayloadEnumTagSinglePayloadFn(), IGM.Int8PtrTy));
+          return addFunction(IGM.getGetMultiPayloadEnumTagSinglePayloadFn());
     goto standard;
   }
   case ValueWitness::StoreEnumTagSinglePayload: {
@@ -1261,8 +1259,7 @@ static void addValueWitness(IRGenModule &IGM, ConstantStructBuilder &B,
       if (auto *enumDecl = boundGenericCharacteristics->concreteType
                                .getEnumOrBoundGenericEnum())
         if (IGM.getMetadataLayout(enumDecl).hasPayloadSizeOffset())
-          return B.add(llvm::ConstantExpr::getBitCast(
-              IGM.getStoreMultiPayloadEnumTagSinglePayloadFn(), IGM.Int8PtrTy));
+          return addFunction(IGM.getStoreMultiPayloadEnumTagSinglePayloadFn());
     goto standard;
   }
 
@@ -1441,7 +1438,7 @@ getAddrOfKnownValueWitnessTable(IRGenModule &IGM, CanType type,
   
   auto &ti = IGM.getTypeInfoForUnlowered(AbstractionPattern::getOpaque(), type);
 
-    // We only have known value witness tables for copyable types currently.
+  // We only have known value witness tables for copyable types currently.
   if (!ti.isCopyable(ResilienceExpansion::Maximal)) {
     return {};
   }
@@ -1454,6 +1451,15 @@ getAddrOfKnownValueWitnessTable(IRGenModule &IGM, CanType type,
   CanType witnessSurrogate;
   ReferenceCounting refCounting;
 
+  // All of our standard value witness tables are bitwise-borrowable and not
+  // addressable for dependencies.
+  if (!ti.isBitwiseBorrowable(ResilienceExpansion::Maximal)
+      || IGM.getTypeProperties(AbstractionPattern::getOpaque(), type,
+                               TypeExpansionContext::minimal())
+            .isAddressableForDependencies()) {
+    return {};
+  }
+
   // Empty types can use empty tuple witnesses.
   if (ti.isKnownEmpty(ResilienceExpansion::Maximal)) {
     witnessSurrogate = TupleType::getEmpty(C);
@@ -1749,7 +1755,7 @@ Address TypeInfo::roundUpToTypeAlignment(IRGenFunction &IGF, Address base,
   Addr = IGF.Builder.CreateNUWAdd(Addr, TyAlignMask);
   llvm::Value *InvertedMask = IGF.Builder.CreateNot(TyAlignMask);
   Addr = IGF.Builder.CreateAnd(Addr, InvertedMask);
-  Addr = IGF.Builder.CreateIntToPtr(Addr, getStorageType()->getPointerTo());
+  Addr = IGF.Builder.CreateIntToPtr(Addr, IGF.IGM.PtrTy);
   return Address(Addr, getStorageType(), Align);
 }
 
diff --git a/lib/IRGen/GenericArguments.h b/lib/IRGen/GenericArguments.h
index a2cf298e0b5a7..87d18049e60cc 100644
--- a/lib/IRGen/GenericArguments.h
+++ b/lib/IRGen/GenericArguments.h
@@ -1,4 +1,4 @@
-//===--- MetadataRequest.cpp - IR generation for metadata requests --------===//
+//===--- GenericArguments.h - IR generation for metadata requests ---------===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -50,8 +50,9 @@ struct GenericArguments {
   /// The values to use to initialize the arguments structure.
   SmallVector<llvm::Value *, 8> Values;
   SmallVector<llvm::Type *, 8> Types;
+  bool hasPacks = false;
 
- void collectTypes(IRGenModule &IGM, NominalTypeDecl *nominal) {
+  void collectTypes(IRGenModule &IGM, NominalTypeDecl *nominal) {
     GenericTypeRequirements requirements(IGM, nominal);
     collectTypes(IGM, requirements);
   }
@@ -59,6 +60,7 @@ struct GenericArguments {
   void collectTypes(IRGenModule &IGM,
                     const GenericTypeRequirements &requirements) {
     for (auto &requirement : requirements.getRequirements()) {
+      hasPacks = hasPacks || requirement.isAnyPack();
       Types.push_back(requirement.getType(IGM));
     }
   }
diff --git a/lib/IRGen/IRABIDetailsProvider.cpp b/lib/IRGen/IRABIDetailsProvider.cpp
index 92e48ce3b14aa..66b4addbeb0a1 100644
--- a/lib/IRGen/IRABIDetailsProvider.cpp
+++ b/lib/IRGen/IRABIDetailsProvider.cpp
@@ -38,6 +38,7 @@
 #include "clang/CodeGen/ModuleBuilder.h"
 #include "clang/CodeGen/SwiftCallingConv.h"
 #include "llvm/IR/DerivedTypes.h"
+#include <optional>
 
 using namespace swift;
 using namespace irgen;
@@ -59,14 +60,25 @@ getPrimitiveTypeFromLLVMType(ASTContext &ctx, const llvm::Type *type) {
     default:
       return std::nullopt;
     }
-  } else if (type->isFloatTy()) {
+  }
+  if (type->isFloatTy()) {
     return ctx.getFloatType();
-  } else if (type->isDoubleTy()) {
+  }
+  if (type->isDoubleTy()) {
     return ctx.getDoubleType();
-  } else if (type->isPointerTy()) {
+  }
+  if (type->isPointerTy()) {
     return ctx.getOpaquePointerType();
   }
-  // FIXME: Handle vector type.
+  if (const auto *vecTy = dyn_cast<llvm::VectorType>(type)) {
+    auto elemTy = getPrimitiveTypeFromLLVMType(ctx, vecTy->getElementType());
+    if (!elemTy)
+      return std::nullopt;
+    auto elemCount = vecTy->getElementCount();
+    if (!elemCount.isFixed())
+      return std::nullopt;
+    return BuiltinVectorType::get(ctx, *elemTy, elemCount.getFixedValue());
+  }
   return std::nullopt;
 }
 
diff --git a/lib/IRGen/IRBuilder.h b/lib/IRGen/IRBuilder.h
index 8885a761debe1..99a506888479b 100644
--- a/lib/IRGen/IRBuilder.h
+++ b/lib/IRGen/IRBuilder.h
@@ -139,11 +139,11 @@ class IRBuilder : public IRBuilderBase {
 
   using IRBuilderBase::CreateOr;
   llvm::Value *CreateOr(llvm::Value *LHS, llvm::Value *RHS,
-                        const Twine &Name = "") {
+                        const Twine &Name = "", bool IsDisjoint = false) {
     if (auto *RC = dyn_cast<llvm::Constant>(RHS))
       if (RC->isNullValue())
         return LHS;  // LHS | 0 -> LHS
-    return IRBuilderBase::CreateOr(LHS, RHS, Name);
+    return IRBuilderBase::CreateOr(LHS, RHS, Name, IsDisjoint);
   }
   llvm::Value *CreateOr(llvm::Value *LHS, const APInt &RHS,
                         const Twine &Name = "") {
@@ -257,10 +257,11 @@ class IRBuilder : public IRBuilderBase {
 
     // Otherwise, cast to a pointer to the correct type.
     auto origPtrType = address.getType();
-    return Address(
-        CreateBitCast(address.getAddress(),
-                      type->getPointerTo(origPtrType->getAddressSpace())),
-        type, address.getAlignment());
+
+    return Address(CreateBitCast(address.getAddress(),
+                                 llvm::PointerType::get(
+                                     Context, origPtrType->getAddressSpace())),
+                   type, address.getAlignment());
   }
 
   /// Insert the given basic block after the IP block and move the
@@ -310,8 +311,8 @@ class IRBuilder : public IRBuilderBase {
   // FunctionPointer.
 
   bool isTrapIntrinsic(llvm::Value *Callee) {
-    return Callee ==
-           llvm::Intrinsic::getDeclaration(getModule(), llvm::Intrinsic::trap);
+    return Callee == llvm::Intrinsic::getOrInsertDeclaration(
+                         getModule(), llvm::Intrinsic::trap);
   }
   bool isTrapIntrinsic(llvm::Intrinsic::ID intrinsicID) {
     return intrinsicID == llvm::Intrinsic::trap;
@@ -381,7 +382,7 @@ class IRBuilder : public IRBuilderBase {
                                       const Twine &name = "") {
     assert(!isTrapIntrinsic(intrinsicID) && "Use CreateNonMergeableTrap");
     auto intrinsicFn =
-      llvm::Intrinsic::getDeclaration(getModule(), intrinsicID);
+        llvm::Intrinsic::getOrInsertDeclaration(getModule(), intrinsicID);
     return CreateCallWithoutDbgLoc(
         cast<llvm::FunctionType>(intrinsicFn->getValueType()), intrinsicFn,
         args, name);
@@ -393,8 +394,8 @@ class IRBuilder : public IRBuilderBase {
                                       ArrayRef<llvm::Value *> args,
                                       const Twine &name = "") {
     assert(!isTrapIntrinsic(intrinsicID) && "Use CreateNonMergeableTrap");
-    auto intrinsicFn =
-      llvm::Intrinsic::getDeclaration(getModule(), intrinsicID, typeArgs);
+    auto intrinsicFn = llvm::Intrinsic::getOrInsertDeclaration(
+        getModule(), intrinsicID, typeArgs);
     return CreateCallWithoutDbgLoc(
         cast<llvm::FunctionType>(intrinsicFn->getValueType()), intrinsicFn,
         args, name);
@@ -502,10 +503,10 @@ class IRBuilder::SavedInsertionPointRAII {
   ~SavedInsertionPointRAII() {
     if (savedInsertionPoint.isNull()) {
       builder.ClearInsertionPoint();
-    } else if (savedInsertionPoint.is<llvm::Instruction *>()) {
-      builder.SetInsertPoint(savedInsertionPoint.get<llvm::Instruction *>());
+    } else if (isa<llvm::Instruction *>(savedInsertionPoint)) {
+      builder.SetInsertPoint(cast<llvm::Instruction *>(savedInsertionPoint));
     } else {
-      builder.SetInsertPoint(savedInsertionPoint.get<llvm::BasicBlock *>());
+      builder.SetInsertPoint(cast<llvm::BasicBlock *>(savedInsertionPoint));
     }
   }
 };
diff --git a/lib/IRGen/IRGen.cpp b/lib/IRGen/IRGen.cpp
index 79de76923f69a..2566667e69027 100644
--- a/lib/IRGen/IRGen.cpp
+++ b/lib/IRGen/IRGen.cpp
@@ -20,6 +20,7 @@
 #include "swift/ABI/MetadataValues.h"
 #include "swift/ABI/ObjectFile.h"
 #include "swift/AST/DiagnosticsIRGen.h"
+#include "swift/AST/DiagnosticsFrontend.h"
 #include "swift/AST/IRGenOptions.h"
 #include "swift/AST/IRGenRequests.h"
 #include "swift/AST/LinkLibrary.h"
@@ -71,6 +72,8 @@
 #include "llvm/Passes/PassBuilder.h"
 #include "llvm/Passes/PassPlugin.h"
 #include "llvm/Passes/StandardInstrumentations.h"
+#include "llvm/Remarks/Remark.h"
+#include "llvm/Remarks/RemarkStreamer.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -85,7 +88,6 @@
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Transforms/IPO/AlwaysInliner.h"
 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
-#include "llvm/Transforms/Instrumentation.h"
 #include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
 #include "llvm/Transforms/Instrumentation/InstrProfiling.h"
 #include "llvm/Transforms/Instrumentation/SanitizerCoverage.h"
@@ -93,6 +95,7 @@
 #include "llvm/Transforms/ObjCARC.h"
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Scalar/DCE.h"
+#include "llvm/Transforms/Utils/Instrumentation.h"
 
 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
 #include "llvm/IR/DiagnosticInfo.h"
@@ -132,6 +135,9 @@ swift::getIRTargetOptions(const IRGenOptions &Opts, ASTContext &Ctx) {
   // FIXME: We should do this entirely through Clang, for consistency.
   TargetOptions TargetOpts;
 
+  // Linker support for this is not widespread enough.
+  TargetOpts.SupportIndirectSymViaGOTPCRel_AArch64_ELF = false;
+
   // Explicitly request debugger tuning for LLDB which is the default
   // on Darwin platforms but not on others.
   TargetOpts.DebuggerTuning = llvm::DebuggerKind::LLDB;
@@ -342,7 +348,8 @@ void swift::performLLVMOptimizations(const IRGenOptions &Opts,
             FPM.addPass(SwiftARCOptPass());
         });
     PB.registerOptimizerLastEPCallback([&](ModulePassManager &MPM,
-                                          OptimizationLevel Level) {
+                                           OptimizationLevel Level,
+                                           llvm::ThinOrFullLTOPhase) {
       if (Level != OptimizationLevel::O0)
         MPM.addPass(createModuleToFunctionPassAdaptor(SwiftARCContractPass()));
       if (Level == OptimizationLevel::O0)
@@ -357,7 +364,8 @@ void swift::performLLVMOptimizations(const IRGenOptions &Opts,
 
   if (Opts.Sanitizers & SanitizerKind::Address) {
     PB.registerOptimizerLastEPCallback([&](ModulePassManager &MPM,
-                                           OptimizationLevel Level) {
+                                           OptimizationLevel Level,
+                                           llvm::ThinOrFullLTOPhase) {
       AddressSanitizerOptions ASOpts;
       ASOpts.CompileKernel = false;
       ASOpts.Recover = bool(Opts.SanitizersWithRecoveryInstrumentation &
@@ -376,17 +384,19 @@ void swift::performLLVMOptimizations(const IRGenOptions &Opts,
   }
 
   if (Opts.Sanitizers & SanitizerKind::Thread) {
-    PB.registerOptimizerLastEPCallback(
-        [&](ModulePassManager &MPM, OptimizationLevel Level) {
-          MPM.addPass(ModuleThreadSanitizerPass());
-          MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
-        });
+    PB.registerOptimizerLastEPCallback([&](ModulePassManager &MPM,
+                                           OptimizationLevel Level,
+                                           llvm::ThinOrFullLTOPhase) {
+      MPM.addPass(ModuleThreadSanitizerPass());
+      MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
+    });
   }
 
   if (Opts.SanitizeCoverage.CoverageType !=
       llvm::SanitizerCoverageOptions::SCK_None) {
     PB.registerOptimizerLastEPCallback([&](ModulePassManager &MPM,
-                                           OptimizationLevel Level) {
+                                           OptimizationLevel Level,
+                                           llvm::ThinOrFullLTOPhase) {
       std::vector<std::string> allowlistFiles;
       std::vector<std::string> ignorelistFiles;
       MPM.addPass(SanitizerCoveragePass(Opts.SanitizeCoverage,
@@ -395,14 +405,15 @@ void swift::performLLVMOptimizations(const IRGenOptions &Opts,
   }
 
   if (RunSwiftSpecificLLVMOptzns && !Opts.DisableLLVMMergeFunctions) {
-    PB.registerOptimizerLastEPCallback(
-        [&](ModulePassManager &MPM, OptimizationLevel Level) {
-          if (Level != OptimizationLevel::O0) {
-            const PointerAuthSchema &schema = Opts.PointerAuth.FunctionPointers;
-            unsigned key = (schema.isEnabled() ? schema.getKey() : 0);
-            MPM.addPass(SwiftMergeFunctionsPass(schema.isEnabled(), key));
-          }
-        });
+    PB.registerOptimizerLastEPCallback([&](ModulePassManager &MPM,
+                                           OptimizationLevel Level,
+                                           llvm::ThinOrFullLTOPhase) {
+      if (Level != OptimizationLevel::O0) {
+        const PointerAuthSchema &schema = Opts.PointerAuth.FunctionPointers;
+        unsigned key = (schema.isEnabled() ? schema.getKey() : 0);
+        MPM.addPass(SwiftMergeFunctionsPass(schema.isEnabled(), key));
+      }
+    });
   }
 
   if (Opts.GenerateProfile) {
@@ -424,7 +435,13 @@ void swift::performLLVMOptimizations(const IRGenOptions &Opts,
   bool isThinLTO = Opts.LLVMLTOKind  == IRGenLLVMLTOKind::Thin;
   bool isFullLTO = Opts.LLVMLTOKind  == IRGenLLVMLTOKind::Full;
   if (!Opts.shouldOptimize() || Opts.DisableLLVMOptzns) {
-    MPM = PB.buildO0DefaultPipeline(level, isFullLTO || isThinLTO);
+    auto phase = llvm::ThinOrFullLTOPhase::None;
+    if (isFullLTO) {
+      phase = llvm::ThinOrFullLTOPhase::FullLTOPreLink;
+    } else if (isThinLTO) {
+      phase = llvm::ThinOrFullLTOPhase::ThinLTOPreLink;
+    }
+    MPM = PB.buildO0DefaultPipeline(level, phase);
   } else if (isThinLTO) {
     MPM = PB.buildThinLTOPreLinkDefaultPipeline(level);
   } else if (isFullLTO) {
@@ -703,32 +720,11 @@ bool swift::performLLVM(const IRGenOptions &Opts,
     assert(Opts.OutputKind == IRGenOutputKind::Module && "no output specified");
   }
 
-  std::string OptRemarksRecordFile;
-  if (Opts.AnnotateCondFailMessage && !OutputFilename.empty()) {
-    OptRemarksRecordFile = std::string(OutputFilename);
-    OptRemarksRecordFile.append(".opt.yaml");
-  }
-
   auto &Ctxt = Module->getContext();
   std::unique_ptr<llvm::DiagnosticHandler> OldDiagnosticHandler =
           Ctxt.getDiagnosticHandler();
   Ctxt.setDiagnosticHandler(std::make_unique<SwiftDiagnosticHandler>(Opts));
 
-  llvm::Expected<std::unique_ptr<llvm::ToolOutputFile>> OptRecordFileOrErr =
-    setupLLVMOptimizationRemarks(Ctxt, OptRemarksRecordFile.c_str(), "annotation-remarks", "yaml",
-                                 false/*RemarksWithHotness*/,
-                                 0/*RemarksHotnessThreshold*/);
-
-  if (Error E = OptRecordFileOrErr.takeError()) {
-    diagnoseSync(Diags, DiagMutex, SourceLoc(), diag::error_opening_output,
-                 StringRef(OptRemarksRecordFile.c_str()),
-                 toString(std::move(E)));
-    return true;
-  }
-
-  std::unique_ptr<llvm::ToolOutputFile> OptRecordFile =
-    std::move(*OptRecordFileOrErr);
-
   performLLVMOptimizations(Opts, Diags, DiagMutex, Module, TargetMachine,
                            OutputFile ? &OutputFile->getOS() : nullptr);
 
@@ -759,10 +755,8 @@ bool swift::performLLVM(const IRGenOptions &Opts,
   }
 
   auto res = compileAndWriteLLVM(Module, TargetMachine, Opts, Stats, Diags,
-                             *OutputFile, DiagMutex,
-                             CASIDFile ? CASIDFile.get() : nullptr);
-  if (OptRecordFile)
-    OptRecordFile->keep();
+                                 *OutputFile, DiagMutex,
+                                 CASIDFile ? CASIDFile.get() : nullptr);
 
   Ctxt.setDiagnosticHandler(std::move(OldDiagnosticHandler));
 
@@ -1067,7 +1061,7 @@ swift::createTargetMachine(const IRGenOptions &Opts, ASTContext &Ctx) {
 
   // Create a target machine.
   llvm::TargetMachine *TargetMachine = Target->createTargetMachine(
-      EffectiveTriple.str(), CPU, targetFeatures, TargetOpts, Reloc::PIC_,
+      EffectiveTriple, CPU, targetFeatures, TargetOpts, Reloc::PIC_,
       cmodel, OptLevel);
   if (!TargetMachine) {
     Ctx.Diags.diagnose(SourceLoc(), diag::no_llvm_target,
@@ -1096,8 +1090,7 @@ static void embedBitcode(llvm::Module *M, const IRGenOptions &Opts)
   // Save llvm.compiler.used and remove it.
   SmallVector<llvm::Constant*, 2> UsedArray;
   SmallVector<llvm::GlobalValue*, 4> UsedGlobals;
-  auto *UsedElementType =
-    llvm::Type::getInt8Ty(M->getContext())->getPointerTo(0);
+  auto *UsedElementType = llvm::PointerType::getUnqual(M->getContext());
   llvm::GlobalVariable *Used =
     collectUsedGlobalVariables(*M, UsedGlobals, true);
   for (auto *GV : UsedGlobals) {
@@ -1166,11 +1159,11 @@ static void embedBitcode(llvm::Module *M, const IRGenOptions &Opts)
   NewUsed->setSection("llvm.metadata");
 }
 
-static void initLLVMModule(const IRGenModule &IGM, SILModule &SIL) {
+static void initLLVMModule(IRGenModule &IGM, SILModule &SIL, std::optional<unsigned> idx = {}) {
   auto *Module = IGM.getModule();
   assert(Module && "Expected llvm:Module for IR generation!");
-  
-  Module->setTargetTriple(IGM.Triple.str());
+
+  Module->setTargetTriple(IGM.Triple);
 
   if (IGM.Context.LangOpts.SDKVersion) {
     if (Module->getSDKVersion().empty())
@@ -1208,8 +1201,69 @@ static void initLLVMModule(const IRGenModule &IGM, SILModule &SIL) {
                                                              "standard-library"),
                                          llvm::ConstantAsMetadata::get(Value)}));
 
-  if (auto *streamer = SIL.getSILRemarkStreamer()) {
-    streamer->intoLLVMContext(Module->getContext());
+  if (auto *SILstreamer = SIL.getSILRemarkStreamer()) {
+    auto remarkStream = SILstreamer->releaseStream();
+    if (remarkStream) {
+      // Install RemarkStreamer into LLVM and keep the remarks file alive. This is
+      // required even if no LLVM remarks are enabled, because the AsmPrinter
+      // serializes meta information about the remarks into the object file.
+      IGM.RemarkStream = std::move(remarkStream);
+      SILstreamer->intoLLVMContext(Context);
+      auto &RS = *IGM.getLLVMContext().getMainRemarkStreamer();
+      if (IGM.getOptions().AnnotateCondFailMessage) {
+        Context.setLLVMRemarkStreamer(
+           std::make_unique<llvm::LLVMRemarkStreamer>(RS));
+      } else {
+        // Don't filter for now.
+        Context.setLLVMRemarkStreamer(
+            std::make_unique<llvm::LLVMRemarkStreamer>(RS));
+      }
+    } else {
+      assert(idx && "Not generating multiple output files?");
+
+      // Construct llvmremarkstreamer objects for LLVM remarks originating in
+      // the LLVM backend and install it in the remaining LLVMModule(s).
+      auto &SILOpts = SIL.getOptions();
+      assert(SILOpts.AuxOptRecordFiles.size() > (*idx - 1));
+
+      const auto &filename = SILOpts.AuxOptRecordFiles[*idx - 1];
+      auto &diagEngine = SIL.getASTContext().Diags;
+      std::error_code errorCode;
+      auto file = std::make_unique<llvm::raw_fd_ostream>(filename, errorCode,
+                                                         llvm::sys::fs::OF_None);
+      if (errorCode) {
+        diagEngine.diagnose(SourceLoc(), diag::cannot_open_file, filename,
+                            errorCode.message());
+        return;
+      }
+
+      const auto format = SILOpts.OptRecordFormat;
+      llvm::Expected<std::unique_ptr<llvm::remarks::RemarkSerializer>>
+        remarkSerializerOrErr = llvm::remarks::createRemarkSerializer(
+          format, llvm::remarks::SerializerMode::Separate, *file);
+      if (llvm::Error err = remarkSerializerOrErr.takeError()) {
+        diagEngine.diagnose(SourceLoc(), diag::error_creating_remark_serializer,
+                            toString(std::move(err)));
+        return;
+      }
+
+      auto auxRS = std::make_unique<llvm::remarks::RemarkStreamer>(
+        std::move(*remarkSerializerOrErr), filename);
+      const auto passes = SILOpts.OptRecordPasses;
+      if (!passes.empty()) {
+        if (llvm::Error err = auxRS->setFilter(passes)) {
+          diagEngine.diagnose(SourceLoc(), diag::error_creating_remark_serializer,
+                          toString(std::move(err)));
+          return ;
+        }
+      }
+
+      Context.setMainRemarkStreamer(std::move(auxRS));
+      Context.setLLVMRemarkStreamer(
+        std::make_unique<llvm::LLVMRemarkStreamer>(
+          *Context.getMainRemarkStreamer()));
+      IGM.RemarkStream = std::move(file);
+    }
   }
 }
 
@@ -1557,6 +1611,7 @@ static void performParallelIRGeneration(IRGenDescriptor desc) {
   auto &Ctx = M->getASTContext();
   // Create an IRGenModule for each source file.
   bool DidRunSILCodeGenPreparePasses = false;
+  unsigned idx = 0;
   for (auto *File : M->getFiles()) {
     auto nextSF = dyn_cast<SourceFile>(File);
     if (!nextSF)
@@ -1573,11 +1628,12 @@ static void performParallelIRGeneration(IRGenDescriptor desc) {
     if (!targetMachine) continue;
 
     // Create the IR emitter.
+    auto outputName = *OutputIter++;
     IRGenModule *IGM = new IRGenModule(
-        irgen, std::move(targetMachine), nextSF, desc.ModuleName, *OutputIter++,
+        irgen, std::move(targetMachine), nextSF, desc.ModuleName, outputName,
         nextSF->getFilename(), nextSF->getPrivateDiscriminator().str());
 
-    initLLVMModule(*IGM, *SILMod);
+    initLLVMModule(*IGM, *SILMod, idx++);
     if (!DidRunSILCodeGenPreparePasses) {
       // Run SIL level IRGen preparation passes on the module the first time
       // around.
@@ -1809,8 +1865,12 @@ void swift::createSwiftModuleObjectFile(SILModule &SILMod, StringRef Buffer,
       llvm::ConstantDataArray::getString(IGM.getLLVMContext(),
                                          Buffer, /*AddNull=*/false);
   auto &M = *IGM.getModule();
+  // Use PrivateLinkage here. The ".swift_ast" section is specially recognized
+  // by LLVM’s object emission and classified as a "metadata" section. On
+  // WebAssembly, metadata symbols must not appear in the object file symbol
+  // table, so using PrivateLinkage avoids exposing the symbol.
   auto *ASTSym = new llvm::GlobalVariable(M, Ty, /*constant*/ true,
-                                          llvm::GlobalVariable::InternalLinkage,
+                                          llvm::GlobalValue::PrivateLinkage,
                                           Data, "__Swift_AST");
 
   std::string Section;
diff --git a/lib/IRGen/IRGenDebugInfo.cpp b/lib/IRGen/IRGenDebugInfo.cpp
index 1ce436971e00c..31a76cd6d4f14 100644
--- a/lib/IRGen/IRGenDebugInfo.cpp
+++ b/lib/IRGen/IRGenDebugInfo.cpp
@@ -672,6 +672,12 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
         case AccessorKind::Read2:
           Kind = ".read2";
           break;
+        case AccessorKind::Borrow:
+          Kind = ".borrow";
+          break;
+        case AccessorKind::Mutate:
+          Kind = ".mutate";
+          break;
         }
 
         SmallVector<char, 64> Buf;
@@ -723,6 +729,16 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
     if (!DC)
       return TheCU;
 
+    auto createContext = [&](NominalTypeDecl &NTD) {
+      GenericContextScope scope(
+          IGM, NTD.getGenericSignature().getCanonicalSignature());
+
+      auto Ty = NTD.getDeclaredInterfaceType();
+      // Create a Forward-declared type.
+      auto DbgTy = DebugTypeInfo::getForwardDecl(Ty);
+      return getOrCreateType(DbgTy);
+    };
+
     if (isa<FuncDecl>(DC))
       if (auto *Decl = IGM.getSILModule().lookUpFunction(SILDeclRef(
               cast<AbstractFunctionDecl>(DC), SILDeclRef::Kind::Func)))
@@ -736,7 +752,6 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
 
     // We don't model these in DWARF.
     case DeclContextKind::Initializer:
-    case DeclContextKind::ExtensionDecl:
     case DeclContextKind::SubscriptDecl:
     case DeclContextKind::EnumElementDecl:
     case DeclContextKind::TopLevelCodeDecl:
@@ -755,16 +770,17 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
       return getOrCreateContext(DC->getParent());
     case DeclContextKind::MacroDecl:
       return getOrCreateContext(DC->getParent());
+    case DeclContextKind::ExtensionDecl: {
+      auto *ED = cast<ExtensionDecl>(DC);
+      if (auto *NTD = ED->getExtendedNominal())
+        return createContext(*NTD);
+      return getOrCreateContext(DC->getParent());
+    }
     case DeclContextKind::GenericTypeDecl: {
-      // The generic signature of this nominal type has no relation to the current
-      // function's generic signature.
+      // The generic signature of this nominal type has no relation to the
+      // current function's generic signature.
       auto *NTD = cast<NominalTypeDecl>(DC);
-      GenericContextScope scope(IGM, NTD->getGenericSignature().getCanonicalSignature());
-
-      auto Ty = NTD->getDeclaredInterfaceType();
-      // Create a Forward-declared type.
-      auto DbgTy = DebugTypeInfo::getForwardDecl(Ty);
-      return getOrCreateType(DbgTy);
+      return createContext(*NTD);
     }
     }
     return TheCU;
@@ -979,7 +995,10 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
       if (Scope)
         return MainFile;
     }
-    return cast<llvm::DIFile>(Scope);
+    if (Scope)
+      return cast<llvm::DIFile>(Scope);
+
+    return MainFile;
   }
 
   static unsigned getStorageSizeInBits(const llvm::DataLayout &DL,
@@ -1066,34 +1085,34 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
       auto &Ctx = Ty->getASTContext();
       Type Reconstructed = Demangle::getTypeForMangling(Ctx, SugaredName, Sig);
       if (!Reconstructed) {
-        llvm::errs() << "Failed to reconstruct type for " << SugaredName
-                     << "\n";
-        llvm::errs() << "Original type:\n";
-        Ty->dump(llvm::errs());
-        if (Sig)
-          llvm::errs() << "Generic signature: " << Sig << "\n";
-        llvm::errs() << SWIFT_CRASH_BUG_REPORT_MESSAGE << "\n"
-          << "Pass '-Xfrontend -disable-round-trip-debug-types' to disable "
-             "this assertion.\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Failed to reconstruct type for " << SugaredName << "\n";
+          out << "Original type:\n";
+          Ty->dump(out);
+          if (Sig)
+            out << "Generic signature: " << Sig << "\n";
+          out << SWIFT_CRASH_BUG_REPORT_MESSAGE << "\n"
+              << "Pass '-Xfrontend -disable-round-trip-debug-types' to disable "
+                 "this assertion.";
+        });
       } else if (!Reconstructed->isEqual(Ty) &&
                  // FIXME: Some existential types are reconstructed without
                  // an explicit ExistentialType wrapping the constraint.
                  !equalWithoutExistentialTypes(Reconstructed, Ty) &&
                  !EqualUpToClangTypes().check(Reconstructed, Ty)) {
         // [FIXME: Include-Clang-type-in-mangling] Remove second check
-        llvm::errs() << "Incorrect reconstructed type for " << SugaredName
-                     << "\n";
-        llvm::errs() << "Original type:\n";
-        Ty->dump(llvm::errs());
-        llvm::errs() << "Reconstructed type:\n";
-        Reconstructed->dump(llvm::errs());
-        if (Sig)
-          llvm::errs() << "Generic signature: " << Sig << "\n";
-        llvm::errs() << SWIFT_CRASH_BUG_REPORT_MESSAGE << "\n"
-          << "Pass '-Xfrontend -disable-round-trip-debug-types' to disable "
-             "this assertion.\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Incorrect reconstructed type for " << SugaredName << "\n";
+          out << "Original type:\n";
+          Ty->dump(out);
+          out << "Reconstructed type:\n";
+          Reconstructed->dump(out);
+          if (Sig)
+            out << "Generic signature: " << Sig << "\n";
+          out << SWIFT_CRASH_BUG_REPORT_MESSAGE << "\n"
+              << "Pass '-Xfrontend -disable-round-trip-debug-types' to disable "
+                 "this assertion.";
+        });
       }
     }
 
@@ -1942,7 +1961,8 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
           nullptr, PtrSize, 0,
           /* DWARFAddressSpace */ std::nullopt, MangledName);
 
-      return DBuilder.createObjectPointerType(PTy);
+      // FIXME: Set DIFlagObjectPointer and make sure it is only set for `self`.
+      return PTy;
     }
     case TypeKind::BuiltinExecutor: {
       return createDoublePointerSizedStruct(
@@ -2310,7 +2330,6 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
     // The following types exist primarily for internal use by the type
     // checker.
     case TypeKind::Error:
-    case TypeKind::Unresolved:
     case TypeKind::LValue:
     case TypeKind::TypeVariable:
     case TypeKind::ErrorUnion:
@@ -2541,10 +2560,10 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
       if (auto Attribute =
               ND->getAttrs().getAttribute<OriginallyDefinedInAttr>()) {
         auto Identifier = IGM.getSILModule().getASTContext().getIdentifier(
-            Attribute->ManglingModuleName);
+            Attribute->getManglingModuleName());
         void *Key = (void *)Identifier.get();
         Scope =
-            getOrCreateModule(Key, TheCU, Attribute->ManglingModuleName, {});
+            getOrCreateModule(Key, TheCU, Attribute->getManglingModuleName(), {});
       } else {
         Context = ND->getParent();
       }
@@ -2577,8 +2596,13 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
 
     // Scope outermost fileprivate decls in an inline private discriminator
     // namespace.
+    //
+    // We need to don't do this for decls imported from Clang modules because
+    // the scopes of C/C++ symbols are not restricted to a particular file unit.
     if (auto *Decl = DbgTy.getDecl())
-      if (Decl->isOutermostPrivateOrFilePrivateScope())
+      if (Decl->isOutermostPrivateOrFilePrivateScope() &&
+          !isa<ClangModuleUnit>(
+              Decl->getDeclContext()->getModuleScopeContext()))
         Scope = getFilePrivateScope(Scope, Decl);
 
     return Scope;
@@ -2670,8 +2694,9 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
       // declarations may not have a unique ID to avoid a forward declaration
       // winning over a full definition.
       auto *FwdDecl = DBuilder.createReplaceableCompositeType(
-          llvm::dwarf::DW_TAG_structure_type, MangledName, Scope, 0, 0,
-          llvm::dwarf::DW_LANG_Swift);
+          llvm::dwarf::DW_TAG_structure_type, Name, Scope, 0, 0,
+          llvm::dwarf::DW_LANG_Swift, 0, 0, llvm::DINode::FlagFwdDecl,
+          MangledName);
       FwdDeclTypes.emplace_back(
           std::piecewise_construct, std::make_tuple(MangledName),
           std::make_tuple(static_cast<llvm::Metadata *>(FwdDecl)));
@@ -3088,7 +3113,7 @@ llvm::DIScope *IRGenDebugInfoImpl::getOrCreateScope(const SILDebugScope *DS) {
     return SP;
   }
 
-  auto *ParentScope = DS->Parent.get<const SILDebugScope *>();
+  auto *ParentScope = cast<const SILDebugScope *>(DS->Parent);
   llvm::DIScope *Parent = getOrCreateScope(ParentScope);
   assert(isa<llvm::DILocalScope>(Parent) && "not a local scope");
 
@@ -3217,6 +3242,11 @@ IRGenDebugInfoImpl::emitFunction(const SILDebugScope *DS, llvm::Function *Fn,
     Name = LinkageName;
   }
 
+  llvm::DISubprogram *ReplaceableType = DBuilder.createTempFunctionFwdDecl(
+      Scope, Name, LinkageName, File, Line, /*Type=*/nullptr, ScopeLine);
+  auto FwdDecl = llvm::TempDISubprogram(ReplaceableType);
+  ScopeCache[DS] = llvm::TrackingMDNodeRef(FwdDecl.get());
+
   CanSILFunctionType FnTy = getFunctionType(SILTy);
   auto Params = Opts.DebugInfoLevel > IRGenDebugInfoLevel::LineTables
                     ? createParameterTypes(SILTy)
@@ -3316,6 +3346,7 @@ IRGenDebugInfoImpl::emitFunction(const SILDebugScope *DS, llvm::Function *Fn,
   if (!DS)
     return nullptr;
 
+  DBuilder.replaceTemporary(std::move(FwdDecl), SP);
   ScopeCache[DS] = llvm::TrackingMDNodeRef(SP);
   return SP;
 }
@@ -3664,16 +3695,16 @@ struct DbgIntrinsicEmitter {
   PointerUnion<llvm::BasicBlock *, llvm::Instruction *> InsertPt;
   irgen::IRBuilder &IRBuilder;
   llvm::DIBuilder &DIBuilder;
-  AddrDbgInstrKind ForceDbgDeclare;
+  AddrDbgInstrKind ForceDbgDeclareOrCoro;
 
   /// Initialize the emitter and initialize the emitter to assume that it is
   /// going to insert an llvm.dbg.declare or an llvm.dbg.addr either at the
   /// current "generalized insertion point" of the IRBuilder. The "generalized
   /// insertion point" is
   DbgIntrinsicEmitter(irgen::IRBuilder &IRBuilder, llvm::DIBuilder &DIBuilder,
-                      AddrDbgInstrKind ForceDebugDeclare)
+                      AddrDbgInstrKind AddrDInstrKind)
       : InsertPt(), IRBuilder(IRBuilder), DIBuilder(DIBuilder),
-        ForceDbgDeclare(ForceDebugDeclare) {
+        ForceDbgDeclareOrCoro(AddrDInstrKind) {
     auto *ParentBB = IRBuilder.GetInsertBlock();
     auto InsertBefore = IRBuilder.GetInsertPoint();
 
@@ -3692,7 +3723,7 @@ struct DbgIntrinsicEmitter {
       return insert(Addr, VarInfo, Expr, DL, Inst);
     } else {
       return insert(Addr, VarInfo, Expr, DL,
-                    InsertPt.get<llvm::BasicBlock *>());
+                    cast<llvm::BasicBlock *>(InsertPt));
     }
   }
 
@@ -3700,19 +3731,29 @@ struct DbgIntrinsicEmitter {
                           llvm::DIExpression *Expr,
                           const llvm::DILocation *DL,
                           llvm::Instruction *InsertBefore) {
-    if (ForceDbgDeclare == AddrDbgInstrKind::DbgDeclare)
-      return DIBuilder.insertDeclare(Addr, VarInfo, Expr, DL, InsertBefore);
+    if (ForceDbgDeclareOrCoro == AddrDbgInstrKind::DbgDeclare)
+      return DIBuilder.insertDeclare(Addr, VarInfo, Expr, DL,
+                                     InsertBefore->getIterator());
+
+    if (ForceDbgDeclareOrCoro == AddrDbgInstrKind::DbgCoroFrameEntry)
+      return DIBuilder.insertCoroFrameEntry(Addr, VarInfo, Expr, DL,
+                                            InsertBefore->getIterator());
+
     Expr = llvm::DIExpression::append(Expr, llvm::dwarf::DW_OP_deref);
     return DIBuilder.insertDbgValueIntrinsic(Addr, VarInfo, Expr, DL,
-                                            InsertBefore);
+                                             InsertBefore->getIterator());
   }
 
   llvm::DbgInstPtr insert(llvm::Value *Addr, llvm::DILocalVariable *VarInfo,
                           llvm::DIExpression *Expr,
                           const llvm::DILocation *DL,
                           llvm::BasicBlock *Block) {
-    if (ForceDbgDeclare == AddrDbgInstrKind::DbgDeclare)
+    if (ForceDbgDeclareOrCoro == AddrDbgInstrKind::DbgDeclare)
       return DIBuilder.insertDeclare(Addr, VarInfo, Expr, DL, Block);
+
+    if (ForceDbgDeclareOrCoro == AddrDbgInstrKind::DbgCoroFrameEntry)
+      return DIBuilder.insertCoroFrameEntry(Addr, VarInfo, Expr, DL, Block);
+
     Expr = llvm::DIExpression::append(Expr, llvm::dwarf::DW_OP_deref);
     return DIBuilder.insertDbgValueIntrinsic(Addr, VarInfo, Expr, DL, Block);
   }
@@ -3772,13 +3813,17 @@ void IRGenDebugInfoImpl::emitDbgIntrinsic(
   if (optimized && (!InCoroContext || !Var->isParameter()))
     AddrDInstKind = AddrDbgInstrKind::DbgValueDeref;
 
+  if (InCoroContext && AddrDInstKind != AddrDbgInstrKind::DbgValueDeref)
+    AddrDInstKind = AddrDbgInstrKind::DbgCoroFrameEntry;
+
   DbgIntrinsicEmitter inserter{Builder, DBuilder, AddrDInstKind};
 
   // If we have a single alloca...
   if (auto *Alloca = dyn_cast<llvm::AllocaInst>(Storage)) {
     auto InsertBefore = Builder.GetInsertPoint();
 
-    if (AddrDInstKind == AddrDbgInstrKind::DbgDeclare) {
+    if (AddrDInstKind == AddrDbgInstrKind::DbgDeclare ||
+        AddrDInstKind == AddrDbgInstrKind::DbgCoroFrameEntry) {
       ParentBlock = Alloca->getParent();
       InsertBefore = std::next(Alloca->getIterator());
     }
@@ -3805,7 +3850,8 @@ void IRGenDebugInfoImpl::emitDbgIntrinsic(
     // splitter that in split coroutines we always create debug info for values
     // in the coroutine context by creating a llvm.dbg.declare for the variable
     // in the entry block of each funclet.
-    if (AddrDInstKind == AddrDbgInstrKind::DbgDeclare) {
+    if (AddrDInstKind == AddrDbgInstrKind::DbgDeclare ||
+        AddrDInstKind == AddrDbgInstrKind::DbgCoroFrameEntry) {
       // Function arguments in async functions are emitted without a shadow copy
       // (that would interfere with coroutine splitting) but with a
       // llvm.dbg.declare to give CoroSplit.cpp license to emit a shadow copy
@@ -3842,25 +3888,29 @@ void IRGenDebugInfoImpl::emitDbgIntrinsic(
       inserter.insert(Storage, Var, Expr, DL, InsertBefore);
     } else {
       inserter.insert(Storage, Var, Expr, DL,
-                      InsertPt.get<llvm::BasicBlock *>());
+                      cast<llvm::BasicBlock *>(InsertPt));
     }
     return;
   }
 
   // Insert a dbg.value at the current insertion point.
-  if (isa<llvm::Argument>(Storage) && !Var->getArg() &&
-      ParentBlock->getFirstNonPHIOrDbg())
-    // SelectionDAGISel only generates debug info for a dbg.value
-    // that is associated with a llvm::Argument if either its !DIVariable
-    // is marked as argument or there is no non-debug intrinsic instruction
-    // before it. So In the case of associating a llvm::Argument with a
-    // non-argument debug variable -- usually via a !DIExpression -- we
-    // need to make sure that dbg.value is before any non-phi / no-dbg
-    // instruction.
-    DBuilder.insertDbgValueIntrinsic(Storage, Var, Expr, DL,
-                                     ParentBlock->getFirstNonPHIOrDbg());
-  else
-    DBuilder.insertDbgValueIntrinsic(Storage, Var, Expr, DL, ParentBlock);
+  if (isa<llvm::Argument>(Storage) && !Var->getArg()) {
+    const auto InsertPt = ParentBlock->getFirstNonPHIOrDbg();
+    if (InsertPt != ParentBlock->end()) {
+      // SelectionDAGISel only generates debug info for a dbg.value
+      // that is associated with a llvm::Argument if either its !DIVariable
+      // is marked as argument or there is no non-debug intrinsic instruction
+      // before it. So In the case of associating a llvm::Argument with a
+      // non-argument debug variable -- usually via a !DIExpression -- we
+      // need to make sure that dbg.value is before any non-phi / no-dbg
+      // instruction.
+      DBuilder.insertDbgValueIntrinsic(Storage, Var, Expr, DL, InsertPt);
+
+      return;
+    }
+  }
+
+  DBuilder.insertDbgValueIntrinsic(Storage, Var, Expr, DL, ParentBlock->end());
 }
 
 void IRGenDebugInfoImpl::emitGlobalVariableDeclaration(
diff --git a/lib/IRGen/IRGenDebugInfo.h b/lib/IRGen/IRGenDebugInfo.h
index 4007bf3178a25..364f357deb3a3 100644
--- a/lib/IRGen/IRGenDebugInfo.h
+++ b/lib/IRGen/IRGenDebugInfo.h
@@ -50,9 +50,10 @@ enum ArtificialKind : bool { RealValue = false, ArtificialValue = true };
 /// instead of dbg.value + op_deref. By default, we now emit dbg.value instead of
 /// dbg.declare for normal variables. This is not true for metadata which
 /// truly are function wide and should be llvm.dbg.declare.
-enum class AddrDbgInstrKind : bool {
+enum class AddrDbgInstrKind : uint8_t {
   DbgDeclare,
   DbgValueDeref,
+  DbgCoroFrameEntry,
 };
 
 /// Helper object that keeps track of the current CompileUnit, File,
diff --git a/lib/IRGen/IRGenFunction.cpp b/lib/IRGen/IRGenFunction.cpp
index e28d1f152d23b..34606f3353a9a 100644
--- a/lib/IRGen/IRGenFunction.cpp
+++ b/lib/IRGen/IRGenFunction.cpp
@@ -63,6 +63,11 @@ IRGenFunction::IRGenFunction(IRGenModule &IGM, llvm::Function *Fn,
 }
 
 IRGenFunction::~IRGenFunction() {
+  // Move the trap basic blocks to the end of the function.
+  for (auto *FailBB : FailBBs) {
+    CurFn->splice(CurFn->end(), CurFn, FailBB->getIterator());
+  }
+
   emitEpilogue();
 
   // Restore the debug location.
@@ -399,7 +404,7 @@ llvm::Value *IRGenFunction::emitLoadOfCompactFunctionPointer(
 void IRGenFunction::emitFakeExplosion(const TypeInfo &type,
                                       Explosion &explosion) {
   if (!isa<LoadableTypeInfo>(type)) {
-    explosion.add(llvm::UndefValue::get(type.getStorageType()->getPointerTo()));
+    explosion.add(llvm::UndefValue::get(IGM.PtrTy));
     return;
   }
 
@@ -407,7 +412,7 @@ void IRGenFunction::emitFakeExplosion(const TypeInfo &type,
   for (auto &element : schema) {
     llvm::Type *elementType;
     if (element.isAggregate()) {
-      elementType = element.getAggregateType()->getPointerTo();
+      elementType = IGM.PtrTy;
     } else {
       elementType = element.getScalarType();
     }
@@ -460,8 +465,7 @@ Address IRGenFunction::emitAddressAtOffset(llvm::Value *base, Offset offset,
     Size objectSize(IGM.DataLayout.getTypeAllocSize(objectTy));
     if (byteOffset.isMultipleOf(objectSize)) {
       // Cast to T*.
-      auto objectPtrTy = objectTy->getPointerTo();
-      base = Builder.CreateBitCast(base, objectPtrTy);
+      base = Builder.CreateBitCast(base, IGM.PtrTy);
 
       // GEP to the slot, computing the index as a signed number.
       auto scaledIndex =
@@ -475,7 +479,7 @@ Address IRGenFunction::emitAddressAtOffset(llvm::Value *base, Offset offset,
 
   // GEP to the slot.
   auto offsetValue = offset.getAsValue(*this);
-  auto slotPtr = emitByteOffsetGEP(base, offsetValue, objectTy);
+  auto slotPtr = emitByteOffsetGEP(base, offsetValue);
   return Address(slotPtr, objectTy, objectAlignment);
 }
 
@@ -520,8 +524,8 @@ llvm::CallInst *IRBuilder::CreateNonMergeableTrap(IRGenModule &IGM,
   }
 
   // Emit the trap instruction.
-  llvm::Function *trapIntrinsic =
-      llvm::Intrinsic::getDeclaration(&IGM.Module, llvm::Intrinsic::trap);
+  llvm::Function *trapIntrinsic = llvm::Intrinsic::getOrInsertDeclaration(
+      &IGM.Module, llvm::Intrinsic::trap);
   if (EnableTrapDebugInfo && IGM.DebugInfo && !failureMsg.empty()) {
     IGM.DebugInfo->addFailureMessageToCurrentLoc(*this, failureMsg);
   }
@@ -543,6 +547,39 @@ void IRGenFunction::emitTrap(StringRef failureMessage, bool EmitUnreachable) {
     Builder.CreateUnreachable();
 }
 
+void IRGenFunction::emitConditionalTrap(llvm::Value *condition, StringRef failureMessage,
+                                        const SILDebugScope *debugScope) {
+  // The condition should be false, or we die.
+  auto expectedCond = Builder.CreateExpect(condition,
+                                           llvm::ConstantInt::get(IGM.Int1Ty, 0));
+
+  // Emit individual fail blocks so that we can map the failure back to a source
+  // line.
+  auto origInsertionPoint = Builder.GetInsertBlock();
+
+  llvm::BasicBlock *failBB = llvm::BasicBlock::Create(IGM.getLLVMContext());
+  llvm::BasicBlock *contBB = llvm::BasicBlock::Create(IGM.getLLVMContext());
+  auto br = Builder.CreateCondBr(expectedCond, failBB, contBB);
+
+  if (IGM.getOptions().AnnotateCondFailMessage && !failureMessage.empty())
+    br->addAnnotationMetadata(failureMessage);
+
+  Builder.SetInsertPoint(&CurFn->back());
+  Builder.emitBlock(failBB);
+  if (IGM.DebugInfo && debugScope) {
+    // If we are emitting DWARF, this does nothing. Otherwise the ``llvm.trap``
+    // instruction emitted from ``Builtin.condfail`` should have an inlined
+    // debug location. This is because zero is not an artificial line location
+    // in CodeView.
+    IGM.DebugInfo->setInlinedTrapLocation(Builder, debugScope);
+  }
+  emitTrap(failureMessage, /*EmitUnreachable=*/true);
+
+  Builder.SetInsertPoint(origInsertionPoint);
+  Builder.emitBlock(contBB);
+  FailBBs.push_back(failBB);
+}
+
 Address IRGenFunction::emitTaskAlloc(llvm::Value *size, Alignment alignment) {
   auto *call = Builder.CreateCall(IGM.getTaskAllocFunctionPointer(), {size});
   call->setDoesNotThrow();
@@ -558,13 +595,6 @@ void IRGenFunction::emitTaskDealloc(Address address) {
   call->setCallingConv(IGM.SwiftCC);
 }
 
-void IRGenFunction::emitTaskDeallocThrough(Address address) {
-  auto *call = Builder.CreateCall(IGM.getTaskDeallocThroughFunctionPointer(),
-                                  {address.getAddress()});
-  call->setDoesNotThrow();
-  call->setCallingConv(IGM.SwiftCC);
-}
-
 llvm::Value *IRGenFunction::alignUpToMaximumAlignment(llvm::Type *sizeTy, llvm::Value *val) {
   auto *alignMask = llvm::ConstantInt::get(sizeTy, MaximumAlignment - 1);
   auto *invertedMask = Builder.CreateNot(alignMask);
@@ -847,8 +877,7 @@ void IRGenFunction::emitAwaitAsyncContinuation(
     auto &resumeTI = cast<LoadableTypeInfo>(getTypeInfo(resumeTy));
     auto resultStorageTy = resumeTI.getStorageType();
     auto resultAddr =
-        Address(Builder.CreateBitOrPointerCast(resultAddrVal,
-                                               resultStorageTy->getPointerTo()),
+        Address(Builder.CreateBitOrPointerCast(resultAddrVal, IGM.PtrTy),
                 resultStorageTy, resumeTI.getFixedAlignment());
     resumeTI.loadAsTake(*this, resultAddr, outDirectResult);
   }
@@ -869,8 +898,8 @@ void IRGenFunction::emitResumeAsyncContinuationReturning(
   // pointer type.
   Address context = emitLoadOfContinuationContext(*this, continuation);
   auto destPtrAddr = emitAddrOfContinuationNormalResultPointer(*this, context);
-  auto destPtr = Builder.CreateBitCast(Builder.CreateLoad(destPtrAddr),
-                                     valueTI.getStorageType()->getPointerTo());
+  auto destPtr =
+      Builder.CreateBitCast(Builder.CreateLoad(destPtrAddr), IGM.PtrTy);
   Address destAddr = valueTI.getAddressForPointer(destPtr);
 
   valueTI.initializeWithTake(*this, destAddr, srcAddr, valueTy,
@@ -907,4 +936,3 @@ void IRGenFunction::emitClearSensitive(Address address, llvm::Value *size) {
   Builder.CreateCall(IGM.getClearSensitiveFunctionPointer(),
                          {address.getAddress(), size});
 }
-
diff --git a/lib/IRGen/IRGenFunction.h b/lib/IRGen/IRGenFunction.h
index cb870b32f8ec3..43f2b3dbb6ff2 100644
--- a/lib/IRGen/IRGenFunction.h
+++ b/lib/IRGen/IRGenFunction.h
@@ -78,6 +78,9 @@ class IRGenFunction {
   OptimizationMode OptMode;
   bool isPerformanceConstraint;
 
+  // Destination basic blocks for condfail traps.
+  llvm::SmallVector<llvm::BasicBlock *, 8> FailBBs;
+
   llvm::Function *const CurFn;
   ModuleDecl *getSwiftModule() const;
   SILModule &getSILModule() const;
@@ -196,6 +199,7 @@ class IRGenFunction {
 
   llvm::Value *emitAsyncResumeProjectContext(llvm::Value *callerContextAddr);
   llvm::Function *getOrCreateResumePrjFn();
+  llvm::Value *popAsyncContext(llvm::Value *calleeContext);
   llvm::Function *createAsyncDispatchFn(const FunctionPointer &fnPtr,
                                         ArrayRef<llvm::Value *> args);
   llvm::Function *createAsyncDispatchFn(const FunctionPointer &fnPtr,
@@ -320,7 +324,6 @@ class IRGenFunction {
   void emitMemCpy(Address dest, Address src, llvm::Value *size);
 
   llvm::Value *emitByteOffsetGEP(llvm::Value *base, llvm::Value *offset,
-                                 llvm::Type *objectType,
                                  const llvm::Twine &name = "");
   Address emitByteOffsetGEP(llvm::Value *base, llvm::Value *offset,
                             const TypeInfo &type,
@@ -392,9 +395,8 @@ class IRGenFunction {
 
   // Emit a call to the given generic type metadata access function.
   MetadataResponse emitGenericTypeMetadataAccessFunctionCall(
-                                          llvm::Function *accessFunction,
-                                          ArrayRef<llvm::Value *> args,
-                                          DynamicMetadataRequest request);
+      llvm::Function *accessFunction, ArrayRef<llvm::Value *> args,
+      DynamicMetadataRequest request, bool hasPacks = false);
 
   // Emit a reference to the canonical type metadata record for the given AST
   // type. This can be used to identify the type at runtime. For types with
@@ -474,6 +476,9 @@ class IRGenFunction {
   /// Emit a non-mergeable trap call, optionally followed by a terminator.
   void emitTrap(StringRef failureMessage, bool EmitUnreachable);
 
+  void emitConditionalTrap(llvm::Value *condition, StringRef failureMessage,
+                           const SILDebugScope *debugScope = nullptr);
+
   /// Given at least a src address to a list of elements, runs body over each
   /// element passing its address. An optional destination address can be
   /// provided which this will run over as well to perform things like
diff --git a/lib/IRGen/IRGenMangler.cpp b/lib/IRGen/IRGenMangler.cpp
index 6ae760fbabe2d..a8a68b585c229 100644
--- a/lib/IRGen/IRGenMangler.cpp
+++ b/lib/IRGen/IRGenMangler.cpp
@@ -13,7 +13,9 @@
 #include "IRGenMangler.h"
 #include "ExtendedExistential.h"
 #include "GenClass.h"
+#include "IRGenModule.h"
 #include "swift/AST/ExistentialLayout.h"
+#include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/IRGenOptions.h"
 #include "swift/AST/ProtocolAssociations.h"
 #include "swift/AST/ProtocolConformance.h"
@@ -414,15 +416,44 @@ std::string IRGenMangler::mangleSymbolNameForAssociatedConformanceWitness(
 std::string IRGenMangler::mangleSymbolNameForMangledMetadataAccessorString(
                                            const char *kind,
                                            CanGenericSignature genericSig,
-                                           CanType type) {
+                                           CanType type,
+                                           MangledTypeRefRole role) {
   beginManglingWithoutPrefix();
   Buffer << kind << " ";
 
-  if (genericSig)
+  if (genericSig) {
     appendGenericSignature(genericSig);
+  }
 
-  if (type)
+  if (type) {
     appendType(type, genericSig);
+  }
+
+  // Noncopyable types get additional runtime capability checks before we reveal
+  // their metadata to reflection APIs, while core metadata queries always provide
+  // the metadata. So we need a separate symbol mangling for the two variants in
+  // this case.
+  switch (role) {
+  case MangledTypeRefRole::DefaultAssociatedTypeWitness:
+  case MangledTypeRefRole::FlatUnique:
+  case MangledTypeRefRole::Metadata:
+    // Core metadata, never conditionalized.
+    break;
+
+  case MangledTypeRefRole::Reflection:
+  case MangledTypeRefRole::FieldMetadata: {
+    // Reflection metadata is conditionalized for noncopyable types.
+    CanType contextType = type;
+    if (genericSig) {
+      contextType = genericSig.getGenericEnvironment()->mapTypeIntoContext(contextType)
+        ->getReducedType(genericSig);
+    }
+    if (contextType->isNoncopyable()) {
+      Buffer << " noncopyable";
+    }
+  }
+  }
+  
   return finalize();
 }
 
diff --git a/lib/IRGen/IRGenMangler.h b/lib/IRGen/IRGenMangler.h
index 4195033d944fb..d3121c56a7e1c 100644
--- a/lib/IRGen/IRGenMangler.h
+++ b/lib/IRGen/IRGenMangler.h
@@ -51,6 +51,8 @@ class IRGenMangler : public Mangle::ASTMangler {
     beginMangling();
     appendEntity(func);
     appendOperator("Tj");
+    if (func->isDistributedThunk())
+      appendSymbolKind(SymbolKind::DistributedThunk);
     return finalize();
   }
 
@@ -86,6 +88,8 @@ class IRGenMangler : public Mangle::ASTMangler {
     beginMangling();
     appendEntity(func);
     appendOperator("Tq");
+    if (func->isDistributedThunk())
+      appendSymbolKind(SymbolKind::DistributedThunk);
     return finalize();
   }
 
@@ -435,10 +439,10 @@ class IRGenMangler : public Mangle::ASTMangler {
   }
 
   std::string
-  mangleAssociatedTypeAccessFunctionDiscriminator(AssociatedType association) {
+  mangleAssociatedTypeAccessFunctionDiscriminator(AssociatedTypeDecl *assocDecl) {
     beginMangling();
-    appendAnyGenericType(association.getSourceProtocol());
-    appendIdentifier(association.getAssociation()->getNameStr());
+    appendAnyGenericType(assocDecl->getProtocol());
+    appendIdentifier(assocDecl->getNameStr());
     return finalize();
   }
 
@@ -681,7 +685,8 @@ class IRGenMangler : public Mangle::ASTMangler {
   std::string mangleSymbolNameForMangledMetadataAccessorString(
                                            const char *kind,
                                            CanGenericSignature genericSig,
-                                           CanType type);
+                                           CanType type,
+                                           MangledTypeRefRole role);
 
   std::string mangleSymbolNameForMangledConformanceAccessorString(
                                            const char *kind,
diff --git a/lib/IRGen/IRGenModule.cpp b/lib/IRGen/IRGenModule.cpp
index 4edb19aa582b9..9ba09c542f9b8 100644
--- a/lib/IRGen/IRGenModule.cpp
+++ b/lib/IRGen/IRGenModule.cpp
@@ -91,6 +91,11 @@ static llvm::StructType *createStructType(IRGenModule &IGM,
                                   name, packed);
 }
 
+llvm::StructType *IRGenModule::createTransientStructType(
+    StringRef name, std::initializer_list<llvm::Type *> types, bool packed) {
+  return createStructType(*this, name, types, packed);
+}
+
 static clang::CodeGenerator *createClangCodeGenerator(ASTContext &Context,
                                                       llvm::LLVMContext &LLVMContext,
                                                       const IRGenOptions &Opts,
@@ -187,9 +192,8 @@ static void checkPointerAuthAssociatedTypeDiscriminator(IRGenModule &IGM, ArrayR
   auto &schema = IGM.getOptions().PointerAuth.ProtocolAssociatedTypeAccessFunctions;
   if (!schema.isEnabled()) return;
 
-  auto decl = dyn_cast_or_null<AssociatedTypeDecl>(lookupSimple(IGM.getSwiftModule(), declPath));
-  assert(decl && "decl not found");
-  auto discriminator = PointerAuthInfo::getOtherDiscriminator(IGM, schema, AssociatedType(decl));
+  auto decl = cast<AssociatedTypeDecl>(lookupSimple(IGM.getSwiftModule(), declPath));
+  auto discriminator = PointerAuthInfo::getOtherDiscriminator(IGM, schema, decl);
   assert(discriminator->getZExtValue() == expected && "discriminator value doesn't match");
 }
 
@@ -261,10 +265,7 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   Int8Ty = llvm::Type::getInt8Ty(getLLVMContext());
   Int16Ty = llvm::Type::getInt16Ty(getLLVMContext());
   Int32Ty = llvm::Type::getInt32Ty(getLLVMContext());
-  Int32PtrTy = Int32Ty->getPointerTo();
   Int64Ty = llvm::Type::getInt64Ty(getLLVMContext());
-  Int8PtrTy = PtrTy;
-  Int8PtrPtrTy = Int8PtrTy->getPointerTo(0);
   SizeTy = DataLayout.getIntPtrType(getLLVMContext(), /*addrspace*/ 0);
 
   // For the relative address type, we want to use the int32 bit type
@@ -277,8 +278,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
     RelativeAddressTy = Int32Ty;
   }
 
-  RelativeAddressPtrTy = RelativeAddressTy->getPointerTo();
-
   FloatTy = llvm::Type::getFloatTy(getLLVMContext());
   DoubleTy = llvm::Type::getDoubleTy(getLLVMContext());
 
@@ -291,15 +290,13 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
     ObjCBoolTy = Int8Ty;
 
   RefCountedStructTy =
-    llvm::StructType::create(getLLVMContext(), "swift.refcounted");
-  RefCountedPtrTy = RefCountedStructTy->getPointerTo(/*addrspace*/ 0);
+      llvm::StructType::create(getLLVMContext(), "swift.refcounted");
   RefCountedNull = llvm::ConstantPointerNull::get(RefCountedPtrTy);
 
   // For now, references storage types are just pointers.
 #define CHECKED_REF_STORAGE(Name, name, ...)                                   \
   Name##ReferenceStructTy =                                                    \
-      createStructType(*this, "swift." #name, {RefCountedPtrTy});              \
-  Name##ReferencePtrTy = Name##ReferenceStructTy->getPointerTo(0);
+      createStructType(*this, "swift." #name, {RefCountedPtrTy});
 #include "swift/AST/ReferenceStorage.def"
 
   // A type metadata record is the structure pointed to by the canonical
@@ -309,8 +306,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   TypeMetadataStructTy = createStructType(*this, "swift.type", {
     MetadataKindTy          // MetadataKind Kind;
   });
-  TypeMetadataPtrTy = TypeMetadataStructTy->getPointerTo(DefaultAS);
-  TypeMetadataPtrPtrTy = TypeMetadataPtrTy->getPointerTo(DefaultAS);
 
   TypeMetadataResponseTy = createStructType(*this, "swift.metadata_response", {
     TypeMetadataPtrTy,
@@ -353,8 +348,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
     RelativeAddressTy,      // superclass
     RelativeAddressTy       // associated type names
   });
-  
-  ProtocolDescriptorPtrTy = ProtocolDescriptorStructTy->getPointerTo();
 
   ProtocolRequirementStructTy =
       createStructType(*this, "swift.protocol_requirement", {
@@ -375,7 +368,7 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
           Int8PtrTy,                              // const char *Labels;
           llvm::ArrayType::get(tupleElementTy, 0) // Element Elements[];
       });
-  TupleTypeMetadataPtrTy = TupleTypeMetadataTy->getPointerTo();
+
   // A full type metadata record is basically just an adjustment to the
   // address point of a type metadata.  Resilience may cause
   // additional data to be laid out prior to this address point.
@@ -386,7 +379,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
     WitnessTablePtrTy,
     TypeMetadataStructTy
   });
-  FullTypeMetadataPtrTy = FullTypeMetadataStructTy->getPointerTo(DefaultAS);
 
   FullForeignTypeMetadataStructTy = createStructType(*this, "swift.full_foreign_type", {
     WitnessTablePtrTy,
@@ -394,7 +386,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   });
 
   DeallocatingDtorTy = llvm::FunctionType::get(VoidTy, RefCountedPtrTy, false);
-  llvm::Type *dtorPtrTy = DeallocatingDtorTy->getPointerTo();
 
   FullExistentialTypeMetadataStructTy = createStructType(*this, "swift.full_existential_type", {
     WitnessTablePtrTy,
@@ -409,23 +400,21 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   FullHeapMetadataStructTy =
                   createStructType(*this, "swift.full_heapmetadata", {
     Int8PtrTy,
-    dtorPtrTy,
+    PtrTy,
     WitnessTablePtrTy,
     TypeMetadataStructTy
   });
-  FullHeapMetadataPtrTy = FullHeapMetadataStructTy->getPointerTo(DefaultAS);
 
   // A full box metadata is non-type heap metadata for a heap allocation of a
   // single value. The box tracks the offset to the value inside the box.
   FullBoxMetadataStructTy =
                   createStructType(*this, "swift.full_boxmetadata", {
-    dtorPtrTy,
+    PtrTy,
     WitnessTablePtrTy,
     TypeMetadataStructTy,
     Int32Ty,
     CaptureDescriptorPtrTy,
   });
-  FullBoxMetadataPtrTy = FullBoxMetadataStructTy->getPointerTo(DefaultAS);
 
   // This must match struct HeapObject in the runtime.
   llvm::Type *refCountedElts[] = {TypeMetadataPtrTy, IntPtrTy};
@@ -441,7 +430,7 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   });
 
   OpaqueTy = llvm::StructType::create(getLLVMContext(), "swift.opaque");
-  OpaquePtrTy = OpaqueTy->getPointerTo(DefaultAS);
+
   NoEscapeFunctionPairTy = createStructType(*this, "swift.noescape.function", {
     FunctionPtrTy,
     OpaquePtrTy,
@@ -451,7 +440,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
     createStructType(*this, "swift.protocolref", {
       RelativeAddressTy
     });
-  ProtocolRecordPtrTy = ProtocolRecordTy->getPointerTo();
 
   ProtocolConformanceDescriptorTy
     = createStructType(*this, "swift.protocol_conformance_descriptor", {
@@ -460,13 +448,9 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
       RelativeAddressTy,
       Int32Ty
     });
-  ProtocolConformanceDescriptorPtrTy
-    = ProtocolConformanceDescriptorTy->getPointerTo(DefaultAS);
 
   TypeContextDescriptorTy
     = llvm::StructType::create(getLLVMContext(), "swift.type_descriptor");
-  TypeContextDescriptorPtrTy
-    = TypeContextDescriptorTy->getPointerTo(DefaultAS);
 
   ClassContextDescriptorTy =
         llvm::StructType::get(getLLVMContext(), {
@@ -510,25 +494,16 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
     = createStructType(*this, "swift.type_metadata_record", {
       RelativeAddressTy
     });
-  TypeMetadataRecordPtrTy
-    = TypeMetadataRecordTy->getPointerTo(DefaultAS);
 
   FieldDescriptorTy
     = llvm::StructType::create(getLLVMContext(), "swift.field_descriptor");
-  FieldDescriptorPtrTy = FieldDescriptorTy->getPointerTo(DefaultAS);
-  FieldDescriptorPtrPtrTy = FieldDescriptorPtrTy->getPointerTo(DefaultAS);
 
   FixedBufferTy = nullptr;
   for (unsigned i = 0; i != MaxNumValueWitnesses; ++i)
     ValueWitnessTys[i] = nullptr;
 
-  ObjCPtrTy = llvm::StructType::create(getLLVMContext(), "objc_object")
-                ->getPointerTo(DefaultAS);
-  BridgeObjectPtrTy = llvm::StructType::create(getLLVMContext(), "swift.bridge")
-                ->getPointerTo(DefaultAS);
-
   ObjCClassStructTy = llvm::StructType::create(getLLVMContext(), "objc_class");
-  ObjCClassPtrTy = ObjCClassStructTy->getPointerTo(DefaultAS);
+
   llvm::Type *objcClassElts[] = {
     ObjCClassPtrTy,
     ObjCClassPtrTy,
@@ -539,15 +514,13 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   ObjCClassStructTy->setBody(objcClassElts);
 
   ObjCSuperStructTy = llvm::StructType::create(getLLVMContext(), "objc_super");
-  ObjCSuperPtrTy = ObjCSuperStructTy->getPointerTo(DefaultAS);
   llvm::Type *objcSuperElts[] = {
     ObjCPtrTy,
     ObjCClassPtrTy
   };
   ObjCSuperStructTy->setBody(objcSuperElts);
-  
+
   ObjCBlockStructTy = llvm::StructType::create(getLLVMContext(), "objc_block");
-  ObjCBlockPtrTy = ObjCBlockStructTy->getPointerTo(DefaultAS);
   llvm::Type *objcBlockElts[] = {
     ObjCClassPtrTy, // isa
     Int32Ty,        // flags
@@ -567,19 +540,15 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   ObjCFullResilientClassStubTy = createStructType(*this, "objc_full_class_stub", {
     SizeTy, // zero padding to appease the linker
     SizeTy, // isa pointer -- always 1
-    ObjCUpdateCallbackTy->getPointerTo() // the update callback
+    PtrTy // the update callback
   });
 
   // What we actually export.
   ObjCResilientClassStubTy = createStructType(*this, "objc_class_stub", {
     SizeTy, // isa pointer -- always 1
-    ObjCUpdateCallbackTy->getPointerTo() // the update callback
+    PtrTy // the update callback
   });
 
-  auto ErrorStructTy = llvm::StructType::create(getLLVMContext(), "swift.error");
-  // ErrorStruct is currently opaque to the compiler.
-  ErrorPtrTy = ErrorStructTy->getPointerTo(DefaultAS);
-  
   llvm::Type *openedErrorTriple[] = {
     OpaquePtrTy,
     TypeMetadataPtrTy,
@@ -588,13 +557,9 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   OpenedErrorTripleTy = llvm::StructType::get(getLLVMContext(),
                                               openedErrorTriple,
                                               /*packed*/ false);
-  OpenedErrorTriplePtrTy = OpenedErrorTripleTy->getPointerTo(DefaultAS);
 
-  WitnessTablePtrPtrTy = WitnessTablePtrTy->getPointerTo(DefaultAS);
-  
   // todo
   OpaqueTypeDescriptorTy = TypeContextDescriptorTy;
-  OpaqueTypeDescriptorPtrTy = OpaqueTypeDescriptorTy->getPointerTo();
 
   InvariantMetadataID = getLLVMContext().getMDKindID("invariant.load");
   InvariantNode = llvm::MDNode::get(getLLVMContext(), {});
@@ -671,12 +636,9 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
 
   DynamicReplacementsTy =
       llvm::StructType::get(getLLVMContext(), {Int8PtrPtrTy, Int8PtrTy});
-  DynamicReplacementsPtrTy = DynamicReplacementsTy->getPointerTo(DefaultAS);
 
   DynamicReplacementLinkEntryTy =
       llvm::StructType::create(getLLVMContext(), "swift.dyn_repl_link_entry");
-  DynamicReplacementLinkEntryPtrTy =
-      DynamicReplacementLinkEntryTy->getPointerTo(DefaultAS);
   llvm::Type *linkEntryFields[] = {
     Int8PtrTy, // function pointer.
     DynamicReplacementLinkEntryPtrTy // next.
@@ -694,7 +656,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   AsyncFunctionPointerTy = createStructType(*this, "swift.async_func_pointer",
                                             {RelativeAddressTy, Int32Ty}, true);
   SwiftContextTy = llvm::StructType::create(getLLVMContext(), "swift.context");
-  SwiftContextPtrTy = SwiftContextTy->getPointerTo(DefaultAS);
 
   // This must match the definition of class AsyncTask in swift/ABI/Task.h.
   SwiftTaskTy = createStructType(*this, "swift.task", {
@@ -705,20 +666,14 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
     Int8PtrTy, Int8PtrTy, // Reserved
     FunctionPtrTy,        // Job.RunJob/Job.ResumeTask
     SwiftContextPtrTy,    // Task.ResumeContext
-    IntPtrTy              // Task.Status
   });
 
-  AsyncFunctionPointerPtrTy = AsyncFunctionPointerTy->getPointerTo(DefaultAS);
-  SwiftTaskPtrTy = SwiftTaskTy->getPointerTo(DefaultAS);
-  SwiftAsyncLetPtrTy = Int8PtrTy; // we pass it opaquely (AsyncLet*)
   SwiftTaskOptionRecordTy =
     llvm::StructType::create(getLLVMContext(), "swift.task_option");
-  SwiftTaskOptionRecordPtrTy = SwiftTaskOptionRecordTy->getPointerTo(DefaultAS);
   SwiftTaskOptionRecordTy->setBody({
     SizeTy,                     // Flags
     SwiftTaskOptionRecordPtrTy, // Parent
   });
-  SwiftTaskGroupPtrTy = Int8PtrTy; // we pass it opaquely (TaskGroup*)
   SwiftTaskGroupTaskOptionRecordTy = createStructType(
       *this, "swift.task_group_task_option", {
     SwiftTaskOptionRecordTy,    // Base option record
@@ -767,13 +722,11 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
     Int8PtrTy, Int8PtrTy, // Reserved
     FunctionPtrTy,        // RunJob/ResumeTask
   });
-  SwiftJobPtrTy = SwiftJobTy->getPointerTo(DefaultAS);
 
   // using TaskContinuationFunction =
   //   SWIFT_CC(swift) void (SWIFT_ASYNC_CONTEXT AsyncContext *);
   TaskContinuationFunctionTy = llvm::FunctionType::get(
       VoidTy, {SwiftContextPtrTy}, /*isVarArg*/ false);
-  TaskContinuationFunctionPtrTy = TaskContinuationFunctionTy->getPointerTo();
 
   SwiftContextTy->setBody({
     SwiftContextPtrTy,             // Parent
@@ -806,8 +759,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
          SwiftExecutorTy       // resume to executor
          });
   }
-  ContinuationAsyncContextPtrTy =
-    ContinuationAsyncContextTy->getPointerTo(DefaultAS);
 
   ClassMetadataBaseOffsetTy = llvm::StructType::get(
       getLLVMContext(), {
@@ -821,8 +772,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
 
   CoroFunctionPointerTy = createStructType(*this, "swift.coro_func_pointer",
                                            {RelativeAddressTy, Int32Ty}, true);
-  CoroFunctionPointerPtrTy = CoroFunctionPointerTy->getPointerTo();
-  CoroAllocationTy = PtrTy;
   CoroAllocateFnTy =
       llvm::FunctionType::get(CoroAllocationTy, SizeTy, /*isVarArg*/ false);
   CoroDeallocateFnTy =
@@ -832,10 +781,9 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   CoroAllocatorTy = createStructType(*this, "swift.coro_allocator",
                                      {
                                          Int32Ty, // CoroAllocator.Flags
-                                         CoroAllocateFnTy->getPointerTo(),
-                                         CoroDeallocateFnTy->getPointerTo(),
+                                         PtrTy,
+                                         PtrTy,
                                      });
-  CoroAllocatorPtrTy = CoroAllocatorTy->getPointerTo();
 }
 
 IRGenModule::~IRGenModule() {
@@ -954,6 +902,14 @@ namespace RuntimeConstants {
     return RuntimeAvailability::AlwaysAvailable;
   }
 
+  RuntimeAvailability TypedCoroAllocAvailability(ASTContext &context) {
+    auto featureAvailability = context.getTypedCoroAllocAvailability();
+    if (!isDeploymentAvailabilityContainedIn(context, featureAvailability)) {
+      return RuntimeAvailability::ConditionallyAvailable;
+    }
+    return RuntimeAvailability::AlwaysAvailable;
+  }
+
   RuntimeAvailability ConcurrencyDiscardingTaskGroupAvailability(ASTContext &context) {
     auto featureAvailability =
         context.getConcurrencyDiscardingTaskGroupAvailability();
@@ -979,6 +935,14 @@ namespace RuntimeConstants {
     return RuntimeAvailability::AlwaysAvailable;
   }
 
+  RuntimeAvailability IsolatedDeinitAvailability(ASTContext &context) {
+    auto featureAvailability = context.getIsolatedDeinitAvailability();
+    if (!isDeploymentAvailabilityContainedIn(context, featureAvailability)) {
+      return RuntimeAvailability::ConditionallyAvailable;
+    }
+    return RuntimeAvailability::AlwaysAvailable;
+  }
+
   RuntimeAvailability
   MultiPayloadEnumTagSinglePayloadAvailability(ASTContext &context) {
     auto featureAvailability = context.getMultiPayloadEnumTagSinglePayload();
@@ -1167,10 +1131,15 @@ llvm::Constant *swift::getRuntimeFn(
 
     if (IGM && useDllStorage(IGM->Triple) && IsExternal) {
       bool bIsImported = true;
+      swift::ASTContext &Context = IGM->Context;
       if (IGM->getSwiftModule()->getPublicModuleName(true).str() == ModuleName)
         bIsImported = false;
-      else if (ModuleDecl *MD = IGM->Context.getModuleByName(ModuleName))
+      else if (ModuleDecl *MD = Context.getModuleByName(ModuleName))
         bIsImported = !MD->isStaticLibrary();
+      else if (strcmp(ModuleName, "BlocksRuntime") == 0)
+        bIsImported =
+            !static_cast<ClangImporter *>(Context.getClangModuleLoader())
+                ->getCodeGenOpts().StaticClosure;
 
       if (bIsImported)
         fn->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
@@ -1230,9 +1199,9 @@ llvm::Constant *IRGenModule::getDeletedAsyncMethodErrorAsyncFunctionPointer() {
 }
 
 llvm::Constant *IRGenModule::
-    getDeletedCalleeAllocatedCoroutineMethodErrorAsyncFunctionPointer() {
+    getDeletedCalleeAllocatedCoroutineMethodErrorCoroFunctionPointer() {
   return getAddrOfLLVMVariableOrGOTEquivalent(
-             LinkEntity::forKnownAsyncFunctionPointer(
+             LinkEntity::forKnownCoroFunctionPointer(
                  "swift_deletedCalleeAllocatedCoroutineMethodError"))
       .getValue();
 }
@@ -1437,7 +1406,7 @@ bool IRGenModule::IsWellKnownBuiltinOrStructralType(CanType T) const {
       T == Context.getAnyObjectType())
     return true;
 
-  if (auto IntTy = dyn_cast<BuiltinIntegerType>(T)) {
+  if (auto IntTy = dyn_cast_or_null<BuiltinIntegerType>(T)) {
     auto Width = IntTy->getWidth();
     if (Width.isPointerWidth())
       return true;
@@ -1461,10 +1430,9 @@ bool IRGenModule::IsWellKnownBuiltinOrStructralType(CanType T) const {
 
 GeneratedModule IRGenModule::intoGeneratedModule() && {
   return GeneratedModule{
-    std::move(LLVMContext),
-    std::unique_ptr<llvm::Module>{ClangCodeGen->ReleaseModule()},
-    std::move(TargetMachine)
-  };
+      std::move(LLVMContext),
+      std::unique_ptr<llvm::Module>{ClangCodeGen->ReleaseModule()},
+      std::move(TargetMachine), std::move(RemarkStream)};
 }
 
 bool IRGenerator::canEmitWitnessTableLazily(SILWitnessTable *wt) {
@@ -2340,6 +2308,22 @@ IRGenModule *IRGenerator::getGenModule(SILFunction *f) {
   return getPrimaryIGM();
 }
 
+IRGenModule *IRGenerator::getGenModule(SILGlobalVariable *v) {
+  if (GenModules.size() == 1) {
+    return getPrimaryIGM();
+  }
+
+  auto found = DefaultIGMForGlobalVariable.find(v);
+  if (found != DefaultIGMForGlobalVariable.end())
+    return found->second;
+
+  if (auto decl = v->getDecl()) {
+    return getGenModule(decl->getDeclContext());
+  }
+
+  return getPrimaryIGM();
+}
+
 uint32_t swift::irgen::getSwiftABIVersion() {
   return IRGenModule::swiftVersion;
 }
@@ -2435,7 +2419,7 @@ bool swift::writeEmptyOutputFilesFor(
     auto *clangImporter = static_cast<ClangImporter *>(
       Context.getClangModuleLoader());
     llvmModule->setTargetTriple(
-      clangImporter->getTargetInfo().getTargetOpts().Triple);
+        llvm::Triple(clangImporter->getTargetInfo().getTargetOpts().Triple));
 
     // Add LLVM module flags.
     auto &clangASTContext = clangImporter->getClangASTContext();
diff --git a/lib/IRGen/IRGenModule.h b/lib/IRGen/IRGenModule.h
index 93bf1f2172f78..6b64264bc93d2 100644
--- a/lib/IRGen/IRGenModule.h
+++ b/lib/IRGen/IRGenModule.h
@@ -92,7 +92,6 @@ namespace clang {
 namespace swift {
   class GenericSignature;
   class AssociatedConformance;
-  class AssociatedType;
   class ASTContext;
   class BaseConformance;
   class BraceStmt;
@@ -229,6 +228,10 @@ class IRGenerator {
   // It is used if a function has no source-file association.
   llvm::DenseMap<SILFunction *, IRGenModule *> DefaultIGMForFunction;
 
+  // Stores the IGM from which a global variable is referenced the first time.
+  // It is used if a global variable has no source-file association.
+  llvm::DenseMap<SILGlobalVariable *, IRGenModule *> DefaultIGMForGlobalVariable;
+
   // The IGMs where specializations of functions are emitted. The key is the
   // non-specialized function.
   // Storing all specializations of a function in the same IGM increases the
@@ -328,6 +331,13 @@ class IRGenerator {
   /// The queue of SIL functions to emit.
   llvm::SmallVector<SILFunction *, 4> LazyFunctionDefinitions;
 
+  /// SIL global variables that have already been lazily emitted, or are
+  /// queued up.
+  llvm::SmallPtrSet<SILGlobalVariable *, 4> LazilyEmittedGlobalVariables;
+
+  /// The queue of SIL global variables to emit.
+  llvm::SmallVector<SILGlobalVariable *, 4> LazyGlobalVariables;
+
   /// Witness tables that have already been lazily emitted, or are queued up.
   llvm::SmallPtrSet<SILWitnessTable *, 4> LazilyEmittedWitnessTables;
 
@@ -389,6 +399,12 @@ class IRGenerator {
   /// first time.
   IRGenModule *getGenModule(SILFunction *f);
 
+  /// Get an IRGenModule for a global variable.
+  /// Returns the IRGenModule of the containing source file, or if this cannot
+  /// be determined, returns the IGM from which the global variable is
+  /// referenced the first time.
+  IRGenModule *getGenModule(SILGlobalVariable *v);
+
   /// Returns the primary IRGenModule. This is the first added IRGenModule.
   /// It is used for everything which cannot be correlated to a specific source
   /// file. And of course, in single-threaded compilation there is only the
@@ -455,6 +471,8 @@ class IRGenerator {
 
   void addLazyFunction(SILFunction *f);
 
+  void addLazyGlobalVariable(SILGlobalVariable *v);
+
   void addDynamicReplacement(SILFunction *f) { DynamicReplacements.insert(f); }
 
   void forceLocalEmitOfLazyFunction(SILFunction *f) {
@@ -651,6 +669,18 @@ struct AccessibleFunction {
                                            llvm::Constant *address);
 };
 
+enum class CStringSectionType {
+  Default,
+  ObjCClassName,
+  ObjCMethodName,
+  ObjCMethodType,
+  OSLogString,
+  // Place all new section types above this line
+  NumTypes,
+  // Place all alias below this line
+  ObjCPropertyName = ObjCMethodName,
+};
+
 /// IRGenModule - Primary class for emitting IR for global declarations.
 /// 
 class IRGenModule {
@@ -675,6 +705,7 @@ class IRGenModule {
   SILModuleConventions silConv;
   ModuleDecl *ObjCModule = nullptr;
   ModuleDecl *ClangImporterModule = nullptr;
+  std::unique_ptr<llvm::raw_fd_ostream> RemarkStream;
 
   llvm::StringMap<ModuleDecl*> OriginalModules;
   llvm::SmallString<128> OutputFilename;
@@ -704,14 +735,11 @@ class IRGenModule {
   bool ShouldUseSwiftError;
 
   llvm::Type *VoidTy;                  /// void (usually {})
-  llvm::PointerType *PtrTy;            /// ptr
   llvm::IntegerType *Int1Ty;           /// i1
   llvm::IntegerType *Int8Ty;           /// i8
   llvm::IntegerType *Int16Ty;          /// i16
   llvm::IntegerType *Int32Ty;          /// i32
-  llvm::PointerType *Int32PtrTy;       /// i32 *
   llvm::IntegerType *RelativeAddressTy;
-  llvm::PointerType *RelativeAddressPtrTy;
   llvm::IntegerType *Int64Ty;          /// i64
   union {
     llvm::IntegerType *SizeTy;         /// usually i32 or i64
@@ -722,31 +750,74 @@ class IRGenModule {
     llvm::IntegerType *ProtocolDescriptorRefTy;
   };
   llvm::IntegerType *ObjCBoolTy;       /// i8 or i1
+
   union {
-    llvm::PointerType *Int8PtrTy;      /// i8*
-    llvm::PointerType *WitnessTableTy;
-    llvm::PointerType *ObjCSELTy;
-    llvm::PointerType *FunctionPtrTy;
+    llvm::PointerType *PtrTy; /// ptr
+
+    llvm::PointerType *BridgeObjectPtrTy; /// %swift.bridge*
     llvm::PointerType *CaptureDescriptorPtrTy;
-  };
-  union {
+    llvm::PointerType *ContinuationAsyncContextPtrTy;
+    llvm::PointerType *CoroAllocationTy;
+    llvm::PointerType *CoroAllocatorPtrTy;
+    llvm::PointerType *CoroFunctionPointerPtrTy;
+    llvm::PointerType *DynamicReplacementLinkEntryPtrTy; /// %link_entry*
+    llvm::PointerType *DynamicReplacementsPtrTy;         /// { i8**, i8* }*
+    llvm::PointerType *ErrorPtrTy;                       /// %swift.error*
+    llvm::PointerType *FieldDescriptorPtrTy;
+    llvm::PointerType *FieldDescriptorPtrPtrTy;
+    llvm::PointerType *FullBoxMetadataPtrTy;  /// %swift.full_boxmetadata*
+    llvm::PointerType *FullHeapMetadataPtrTy; /// %swift.full_heapmetadata*
+    llvm::PointerType *FullTypeMetadataPtrTy; /// %swift.full_type*
+    llvm::PointerType *FunctionPtrTy;
+    llvm::PointerType *Int8PtrTy;      /// i8*
     llvm::PointerType *Int8PtrPtrTy;   /// i8**
+    llvm::PointerType *Int32PtrTy;     /// i32 *
+    llvm::PointerType *ObjCBlockPtrTy; /// %objc_block*
+    llvm::PointerType *ObjCClassPtrTy; /// %objc_class*
+    llvm::PointerType *ObjCPtrTy;      /// %objc_object*
+    llvm::PointerType *ObjCSELTy;
+    llvm::PointerType *ObjCSuperPtrTy; /// %objc_super*
+    llvm::PointerType *OpaquePtrTy;    /// %swift.opaque*
+    llvm::PointerType *OpaqueTypeDescriptorPtrTy;
+    llvm::PointerType
+        *OpenedErrorTriplePtrTy; /// { %swift.opaque*, %swift.type*, i8** }*
+    llvm::PointerType *ProtocolConformanceDescriptorPtrTy;
+    llvm::PointerType *ProtocolDescriptorPtrTy; /// %swift.protocol*
+    llvm::PointerType *ProtocolRecordPtrTy;
+    llvm::PointerType *RelativeAddressPtrTy;
+    llvm::PointerType *RefCountedPtrTy; /// %swift.refcounted*
+#define CHECKED_REF_STORAGE(Name, ...)                                         \
+  llvm::PointerType *Name##ReferencePtrTy; /// %swift. #name _reference*
+#include "swift/AST/ReferenceStorage.def"
+    llvm::PointerType *SwiftAsyncLetPtrTy;
+    llvm::PointerType *SwiftContextPtrTy;
+    llvm::PointerType *SwiftJobPtrTy;
+    llvm::PointerType *SwiftTaskGroupPtrTy;
+    llvm::PointerType *SwiftTaskOptionRecordPtrTy;
+    llvm::PointerType *SwiftTaskPtrTy;
+    llvm::PointerType *AsyncFunctionPointerPtrTy;
+    llvm::PointerType *TaskContinuationFunctionPtrTy;
+    llvm::PointerType *TupleTypeMetadataPtrTy; /// %swift.tuple_type*
+    llvm::PointerType *TypeContextDescriptorPtrTy;
+    llvm::PointerType *TypeMetadataPtrTy;    /// %swift.type*
+    llvm::PointerType *TypeMetadataPtrPtrTy; /// %swift.type**
+    llvm::PointerType *TypeMetadataRecordPtrTy;
+    llvm::PointerType *UnknownRefCountedPtrTy;
     llvm::PointerType *WitnessTablePtrTy;
+    llvm::PointerType *WitnessTablePtrPtrTy; /// i8***
+    llvm::PointerType *WitnessTableTy;
   };
+
   llvm::StructType *RefCountedStructTy;/// %swift.refcounted = type { ... }
   Size RefCountedStructSize;           /// sizeof(%swift.refcounted)
-  llvm::PointerType *RefCountedPtrTy;  /// %swift.refcounted*
 #define CHECKED_REF_STORAGE(Name, ...)                                         \
-  llvm::StructType *Name##ReferenceStructTy;                                   \
-  llvm::PointerType *Name##ReferencePtrTy; /// %swift. #name _reference*
+  llvm::StructType *Name##ReferenceStructTy; /// %swift. #name _reference
 #include "swift/AST/ReferenceStorage.def"
   llvm::Constant *RefCountedNull;      /// %swift.refcounted* null
   llvm::StructType *FunctionPairTy;    /// { i8*, %swift.refcounted* }
   llvm::StructType *NoEscapeFunctionPairTy;    /// { i8*, %swift.opaque* }
   llvm::FunctionType *DeallocatingDtorTy; /// void (%swift.refcounted*)
   llvm::StructType *TypeMetadataStructTy; /// %swift.type = type { ... }
-  llvm::PointerType *TypeMetadataPtrTy;/// %swift.type*
-  llvm::PointerType *TypeMetadataPtrPtrTy; /// %swift.type**
   union {
     llvm::StructType *TypeMetadataResponseTy;   /// { %swift.type*, iSize }
     llvm::StructType *TypeMetadataDependencyTy; /// { %swift.type*, iSize }
@@ -755,63 +826,36 @@ class IRGenModule {
   llvm::StructType *FullTypeLayoutTy;  /// %swift.full_type_layout = { ... }
   llvm::StructType *TypeLayoutTy;  /// %swift.type_layout = { ... }
   llvm::StructType *TupleTypeMetadataTy;     /// %swift.tuple_type
-  llvm::PointerType *TupleTypeMetadataPtrTy; /// %swift.tuple_type*
   llvm::StructType *FullHeapMetadataStructTy; /// %swift.full_heapmetadata = type { ... }
-  llvm::PointerType *FullHeapMetadataPtrTy;/// %swift.full_heapmetadata*
   llvm::StructType *FullBoxMetadataStructTy; /// %swift.full_boxmetadata = type { ... }
-  llvm::PointerType *FullBoxMetadataPtrTy;/// %swift.full_boxmetadata*
   llvm::StructType *FullTypeMetadataStructTy; /// %swift.full_type = type { ... }
   llvm::StructType *FullExistentialTypeMetadataStructTy; /// %swift.full_existential_type = type { ... }
-  llvm::PointerType *FullTypeMetadataPtrTy;/// %swift.full_type*
   llvm::StructType *FullForeignTypeMetadataStructTy; /// %swift.full_foreign_type = type { ... }
   llvm::StructType *ProtocolDescriptorStructTy; /// %swift.protocol = type { ... }
-  llvm::PointerType *ProtocolDescriptorPtrTy; /// %swift.protocol*
   llvm::StructType *ProtocolRequirementStructTy; /// %swift.protocol_requirement
-  union {
-    llvm::PointerType *ObjCPtrTy;      /// %objc_object*
-    llvm::PointerType *UnknownRefCountedPtrTy;
-  };
-  llvm::PointerType *BridgeObjectPtrTy;/// %swift.bridge*
   llvm::StructType *OpaqueTy;          /// %swift.opaque
-  llvm::PointerType *OpaquePtrTy;      /// %swift.opaque*
   llvm::StructType *ObjCClassStructTy; /// %objc_class
-  llvm::PointerType *ObjCClassPtrTy;   /// %objc_class*
   llvm::StructType *ObjCSuperStructTy; /// %objc_super
-  llvm::PointerType *ObjCSuperPtrTy;   /// %objc_super*
   llvm::StructType *ObjCBlockStructTy; /// %objc_block
-  llvm::PointerType *ObjCBlockPtrTy;   /// %objc_block*
   llvm::FunctionType *ObjCUpdateCallbackTy;
   llvm::StructType *ObjCFullResilientClassStubTy;   /// %objc_full_class_stub
   llvm::StructType *ObjCResilientClassStubTy;   /// %objc_class_stub
   llvm::StructType *ProtocolRecordTy;
-  llvm::PointerType *ProtocolRecordPtrTy;
   llvm::StructType *ProtocolConformanceDescriptorTy;
-  llvm::PointerType *ProtocolConformanceDescriptorPtrTy;
   llvm::StructType *TypeContextDescriptorTy;
-  llvm::PointerType *TypeContextDescriptorPtrTy;
   llvm::StructType *ClassContextDescriptorTy;
   llvm::StructType *MethodDescriptorStructTy; /// %swift.method_descriptor
   llvm::StructType *MethodOverrideDescriptorStructTy; /// %swift.method_override_descriptor
   llvm::StructType *MethodDefaultOverrideDescriptorStructTy; /// %swift.method_default_override_descriptor
   llvm::StructType *TypeMetadataRecordTy;
-  llvm::PointerType *TypeMetadataRecordPtrTy;
   llvm::StructType *FieldDescriptorTy;
-  llvm::PointerType *FieldDescriptorPtrTy;
-  llvm::PointerType *FieldDescriptorPtrPtrTy;
-  llvm::PointerType *ErrorPtrTy;       /// %swift.error*
   llvm::StructType *OpenedErrorTripleTy; /// { %swift.opaque*, %swift.type*, i8** }
-  llvm::PointerType *OpenedErrorTriplePtrTy; /// { %swift.opaque*, %swift.type*, i8** }*
-  llvm::PointerType *WitnessTablePtrPtrTy;   /// i8***
   llvm::StructType *OpaqueTypeDescriptorTy;
-  llvm::PointerType *OpaqueTypeDescriptorPtrTy;
   llvm::Type *FloatTy;
   llvm::Type *DoubleTy;
   llvm::StructType *DynamicReplacementsTy; // { i8**, i8* }
-  llvm::PointerType *DynamicReplacementsPtrTy;
 
   llvm::StructType *DynamicReplacementLinkEntryTy; // %link_entry = { i8*, %link_entry*}
-  llvm::PointerType
-      *DynamicReplacementLinkEntryPtrTy; // %link_entry*
   llvm::StructType *DynamicReplacementKeyTy; // { i32, i32}
 
   llvm::StructType *AccessibleFunctionRecordTy; // { i32*, i32*, i32*, i32}
@@ -822,12 +866,6 @@ class IRGenModule {
   llvm::StructType *SwiftTaskTy;
   llvm::StructType *SwiftJobTy;
   llvm::StructType *SwiftExecutorTy;
-  llvm::PointerType *AsyncFunctionPointerPtrTy;
-  llvm::PointerType *SwiftContextPtrTy;
-  llvm::PointerType *SwiftTaskPtrTy;
-  llvm::PointerType *SwiftAsyncLetPtrTy;
-  llvm::PointerType *SwiftTaskOptionRecordPtrTy;
-  llvm::PointerType *SwiftTaskGroupPtrTy;
   llvm::StructType  *SwiftTaskOptionRecordTy;
   llvm::StructType  *SwiftInitialSerialExecutorTaskOptionRecordTy;
   llvm::StructType  *SwiftTaskGroupTaskOptionRecordTy;
@@ -835,32 +873,31 @@ class IRGenModule {
   llvm::StructType  *SwiftInitialTaskExecutorOwnedPreferenceTaskOptionRecordTy;
   llvm::StructType  *SwiftInitialTaskNameTaskOptionRecordTy;
   llvm::StructType  *SwiftResultTypeInfoTaskOptionRecordTy;
-  llvm::PointerType *SwiftJobPtrTy;
   llvm::IntegerType *ExecutorFirstTy;
   llvm::IntegerType *ExecutorSecondTy;
   llvm::FunctionType *TaskContinuationFunctionTy;
-  llvm::PointerType *TaskContinuationFunctionPtrTy;
   llvm::StructType *AsyncTaskAndContextTy;
   llvm::StructType *ContinuationAsyncContextTy;
-  llvm::PointerType *ContinuationAsyncContextPtrTy;
   llvm::StructType *ClassMetadataBaseOffsetTy;
   llvm::StructType *DifferentiabilityWitnessTy; // { i8*, i8* }
   // clang-format on
 
   llvm::StructType *CoroFunctionPointerTy; // { i32, i32 }
-  llvm::PointerType *CoroFunctionPointerPtrTy;
-  llvm::PointerType *CoroAllocationTy;
   llvm::FunctionType *CoroAllocateFnTy;
   llvm::FunctionType *CoroDeallocateFnTy;
   llvm::IntegerType *CoroAllocatorFlagsTy;
   llvm::StructType *CoroAllocatorTy;
-  llvm::PointerType *CoroAllocatorPtrTy;
 
   llvm::GlobalVariable *TheTrivialPropertyDescriptor = nullptr;
 
   llvm::Constant *swiftImmortalRefCount = nullptr;
   llvm::Constant *swiftStaticArrayMetadata = nullptr;
 
+  llvm::StructType *
+  createTransientStructType(StringRef name,
+                            std::initializer_list<llvm::Type *> types,
+                            bool packed = false);
+
   /// Used to create unique names for class layout types with tail allocated
   /// elements.
   unsigned TailElemTypeID = 0;
@@ -925,6 +962,8 @@ class IRGenModule {
 
   llvm::Type *getReferenceType(ReferenceCounting style);
 
+  llvm::PointerType *getOpaquePointerType(unsigned AddressSpace) const;
+
   static bool isLoadableReferenceAddressOnly(ReferenceCounting style) {
     switch (style) {
     case ReferenceCounting::Native:
@@ -964,7 +1003,6 @@ class IRGenModule {
                                                ReferenceCounting style) const;
 
   llvm::Type *getFixedBufferTy();
-  llvm::PointerType *getExistentialPtrTy(unsigned numTables);
   llvm::Type *getExistentialType(unsigned numTables);
   llvm::Type *getValueWitnessTy(ValueWitness index);
   Signature getValueWitnessSignature(ValueWitness index);
@@ -973,8 +1011,6 @@ class IRGenModule {
 
   llvm::StructType *getValueWitnessTableTy();
   llvm::StructType *getEnumValueWitnessTableTy();
-  llvm::PointerType *getValueWitnessTablePtrTy();
-  llvm::PointerType *getEnumValueWitnessTablePtrTy();
 
   llvm::IntegerType *getTypeMetadataRequestParamTy();
   llvm::StructType *getTypeMetadataResponseTy();
@@ -1070,6 +1106,12 @@ class IRGenModule {
   SILType getLoweredType(AbstractionPattern orig, Type subst) const;
   SILType getLoweredType(Type subst) const;
   const Lowering::TypeLowering &getTypeLowering(SILType type) const;
+  SILTypeProperties getTypeProperties(SILType type) const;
+  SILTypeProperties getTypeProperties(SILType type,
+                                      TypeExpansionContext forExpansion) const;
+  SILTypeProperties getTypeProperties(AbstractionPattern origType,
+                                      Type substType,
+                                      TypeExpansionContext forExpansion) const;
   bool isTypeABIAccessible(SILType type) const;
 
   const TypeInfo &getTypeInfoForUnlowered(AbstractionPattern orig,
@@ -1096,9 +1138,6 @@ class IRGenModule {
   llvm::Type *getStorageTypeForUnlowered(Type T);
   llvm::Type *getStorageTypeForLowered(CanType T);
   llvm::Type *getStorageType(SILType T);
-  llvm::PointerType *getStoragePointerTypeForUnlowered(Type T);
-  llvm::PointerType *getStoragePointerTypeForLowered(CanType T);
-  llvm::PointerType *getStoragePointerType(SILType T);
   llvm::StructType *createNominalType(CanType type);
   llvm::StructType *createNominalType(ProtocolCompositionType *T);
   clang::CanQual<clang::Type> getClangType(CanType type);
@@ -1118,6 +1157,7 @@ class IRGenModule {
   clang::CodeGen::CodeGenModule &getClangCGM() const;
   
   CanType getRuntimeReifiedType(CanType type);
+  Type substOpaqueTypesWithUnderlyingTypes(Type type);
   CanType substOpaqueTypesWithUnderlyingTypes(CanType type);
   SILType substOpaqueTypesWithUnderlyingTypes(SILType type, CanGenericSignature genericSig);
   std::pair<CanType, ProtocolConformanceRef>
@@ -1175,9 +1215,10 @@ class IRGenModule {
   std::pair<llvm::GlobalVariable *, llvm::Constant *> createStringConstant(
       StringRef Str, bool willBeRelativelyAddressed = false,
       StringRef sectionName = "", StringRef name = "");
-  llvm::Constant *getAddrOfGlobalString(StringRef utf8,
-                                        bool willBeRelativelyAddressed = false,
-                                        bool useOSLogSection = false);
+  llvm::Constant *getAddrOfGlobalString(
+      StringRef utf8,
+      CStringSectionType sectionType = CStringSectionType::Default,
+      bool willBeRelativelyAddressed = false);
   llvm::Constant *getAddrOfGlobalUTF16String(StringRef utf8);
   llvm::Constant *
   getAddrOfGlobalIdentifierString(StringRef utf8,
@@ -1301,10 +1342,11 @@ class IRGenModule {
   llvm::DenseMap<LinkEntity, llvm::Constant*> GlobalGOTEquivalents;
   llvm::DenseMap<LinkEntity, llvm::Function*> GlobalFuncs;
   llvm::DenseSet<const clang::Decl *> GlobalClangDecls;
-  llvm::StringMap<std::pair<llvm::GlobalVariable*, llvm::Constant*>>
-    GlobalStrings;
-  llvm::StringMap<std::pair<llvm::GlobalVariable*, llvm::Constant*>>
-    GlobalOSLogStrings;
+  // Maps sectionName -> string data -> constant
+  std::array<
+      llvm::StringMap<std::pair<llvm::GlobalVariable *, llvm::Constant *>>,
+      static_cast<size_t>(CStringSectionType::NumTypes)>
+      GlobalStrings;
   llvm::StringMap<llvm::Constant*> GlobalUTF16Strings;
   llvm::StringMap<std::pair<llvm::GlobalVariable*, llvm::Constant*>>
     StringsForTypeRef;
@@ -1398,8 +1440,14 @@ class IRGenModule {
   friend struct ::llvm::DenseMapInfo<swift::irgen::IRGenModule::FixedLayoutKey>;
   llvm::DenseMap<FixedLayoutKey, llvm::Constant *> PrivateFixedLayouts;
 
+  /// Captures a static object layout.
+  struct StaticObjectLayout {
+    std::unique_ptr<StructLayout> layout;
+    llvm::StructType *containerTy = nullptr;
+  };
+
   /// A cache for layouts of statically initialized objects.
-  llvm::DenseMap<SILGlobalVariable *, std::unique_ptr<StructLayout>>
+  llvm::DenseMap<SILGlobalVariable *, StaticObjectLayout>
     StaticObjectLayouts;
 
   /// A mapping from order numbers to the LLVM functions which we
@@ -1509,6 +1557,15 @@ class IRGenModule {
   const char *getReflectionTypeRefSectionName();
   const char *getMultiPayloadEnumDescriptorSectionName();
 
+  static constexpr const char ObjCClassNameSectionName[] =
+      "__TEXT,__objc_classname,cstring_literals";
+  static constexpr const char ObjCMethodNameSectionName[] =
+      "__TEXT,__objc_methname,cstring_literals";
+  static constexpr const char ObjCMethodTypeSectionName[] =
+      "__TEXT,__objc_methtype,cstring_literals";
+  static constexpr const char OSLogStringSectionName[] =
+      "__TEXT,__oslogstring,cstring_literals";
+
   /// Returns the special builtin types that should be emitted in the stdlib
   /// module.
   llvm::ArrayRef<CanType> getOrCreateSpecialStlibBuiltinTypes();
@@ -1532,7 +1589,7 @@ class IRGenModule {
   llvm::AttributeList getAllocAttrs();
   llvm::Constant *getDeletedAsyncMethodErrorAsyncFunctionPointer();
   llvm::Constant *
-  getDeletedCalleeAllocatedCoroutineMethodErrorAsyncFunctionPointer();
+  getDeletedCalleeAllocatedCoroutineMethodErrorCoroFunctionPointer();
 
 private:
   llvm::Constant *EmptyTupleMetadata = nullptr;
@@ -1865,7 +1922,8 @@ private:                                                                       \
 
   void emitDynamicReplacementOriginalFunctionThunk(SILFunction *f);
 
-  llvm::Function *getAddrOfContinuationPrototype(CanSILFunctionType fnType);
+  llvm::Function *getAddrOfContinuationPrototype(CanSILFunctionType fnType,
+                                                 CanGenericSignature sig);
   Address getAddrOfSILGlobalVariable(SILGlobalVariable *var,
                                      const TypeInfo &ti,
                                      ForDefinition_t forDefinition);
diff --git a/lib/IRGen/IRGenRequests.cpp b/lib/IRGen/IRGenRequests.cpp
index a2555fc5f5978..0c6a63c9d15f6 100644
--- a/lib/IRGen/IRGenRequests.cpp
+++ b/lib/IRGen/IRGenRequests.cpp
@@ -42,7 +42,7 @@ void swift::simple_display(llvm::raw_ostream &out,
   if (MD) {
     out << "IR Generation for module " << MD->getName();
   } else {
-    auto *file = desc.Ctx.get<FileUnit *>();
+    auto *file = cast<FileUnit *>(desc.Ctx);
     out << "IR Generation for file ";
     simple_display(out, file);
   }
@@ -64,7 +64,7 @@ TinyPtrVector<FileUnit *> IRGenDescriptor::getFilesToEmit() const {
 
   // For a primary file, we emit IR for both it and potentially its
   // SynthesizedFileUnit.
-  auto *primary = Ctx.get<FileUnit *>();
+  auto *primary = cast<FileUnit *>(Ctx);
   TinyPtrVector<FileUnit *> files;
   files.push_back(primary);
 
@@ -74,14 +74,14 @@ TinyPtrVector<FileUnit *> IRGenDescriptor::getFilesToEmit() const {
 ModuleDecl *IRGenDescriptor::getParentModule() const {
   if (auto *file = Ctx.dyn_cast<FileUnit *>())
     return file->getParentModule();
-  return Ctx.get<ModuleDecl *>();
+  return cast<ModuleDecl *>(Ctx);
 }
 
 TBDGenDescriptor IRGenDescriptor::getTBDGenDescriptor() const {
   if (auto *file = Ctx.dyn_cast<FileUnit *>()) {
     return TBDGenDescriptor::forFile(file, TBDOpts);
   } else {
-    auto *M = Ctx.get<ModuleDecl *>();
+    auto *M = cast<ModuleDecl *>(Ctx);
     return TBDGenDescriptor::forModule(M, TBDOpts);
   }
 }
@@ -97,11 +97,11 @@ evaluator::DependencySource IRGenRequest::readDependencySource(
   auto &desc = std::get<0>(getStorage());
 
   // We don't track dependencies in whole-module mode.
-  if (desc.Ctx.is<ModuleDecl *>()) {
+  if (isa<ModuleDecl *>(desc.Ctx)) {
     return nullptr;
   }
 
-  auto *primary = desc.Ctx.get<FileUnit *>();
+  auto *primary = cast<FileUnit *>(desc.Ctx);
   return dyn_cast<SourceFile>(primary);
 }
 
diff --git a/lib/IRGen/IRGenSIL.cpp b/lib/IRGen/IRGenSIL.cpp
index 3aabe05c04b12..a26668c5f22f4 100644
--- a/lib/IRGen/IRGenSIL.cpp
+++ b/lib/IRGen/IRGenSIL.cpp
@@ -420,9 +420,6 @@ class IRGenSILFunction :
 
   llvm::MapVector<SILBasicBlock *, LoweredBB> LoweredBBs;
   
-  // Destination basic blocks for condfail traps.
-  llvm::SmallVector<llvm::BasicBlock *, 8> FailBBs;
-
   SILFunction *CurSILFn;
   // If valid, the address by means of which a return--which is direct in
   // SIL--is passed indirectly in IR.  Such indirection is necessary when the
@@ -574,8 +571,8 @@ class IRGenSILFunction :
     auto &ti = getTypeInfo(t);
     switch (t.getCategory()) {
     case SILValueCategory::Address: {
-      Address undefAddr = ti.getAddressForPointer(
-                  llvm::UndefValue::get(ti.getStorageType()->getPointerTo()));
+      Address undefAddr =
+          ti.getAddressForPointer(llvm::UndefValue::get(IGM.PtrTy));
       LoweredUndefs.insert({t, LoweredValue(undefAddr)});
       break;
     }
@@ -826,7 +823,7 @@ class IRGenSILFunction :
           if (DVI->getParent() == BB)
             IGM.DebugInfo->getBuilder().insertDbgValueIntrinsic(
                 DVI->getValue(), DVI->getVariable(), DVI->getExpression(),
-                DVI->getDebugLoc(), &*CurBB->getFirstInsertionPt());
+                DVI->getDebugLoc(), CurBB->getFirstInsertionPt());
       }
     }
   }
@@ -910,7 +907,7 @@ class IRGenSILFunction :
 
       llvm::Instruction *Cloned = Orig->clone();
       Cloned->setOperand(0, Inner);
-      Cloned->insertBefore(Orig);
+      Cloned->insertBefore(Orig->getIterator());
       return static_cast<llvm::Value *>(Cloned);
     };
     if (auto *LdInst = dyn_cast<llvm::LoadInst>(Storage))
@@ -1158,12 +1155,10 @@ class IRGenSILFunction :
           }
 
           emitTypeMetadataRef(archetype);
-        } else if (auto packArchetype = dyn_cast<PackArchetypeType>(t)) {
-          emitTypeMetadataRef(packArchetype);
-        } else if (auto packtype = dyn_cast<SILPackType>(t)) {
+        } else if (auto packType = dyn_cast<SILPackType>(t)) {
           llvm::Value *Shape = emitPackShapeExpression(t);
           emitPackCountDebugVariable(Shape);
-        } else if (auto packtype = dyn_cast<PackType>(t)) {
+        } else if (auto packType = dyn_cast<PackType>(t)) {
           llvm::Value *Shape = emitPackShapeExpression(t);
           emitPackCountDebugVariable(Shape);
         }
@@ -1192,27 +1187,24 @@ class IRGenSILFunction :
         ArtificialKind::RealValue, DbgInstrKind);
   }
 
-  void emitFailBB() {
-    if (!FailBBs.empty()) {
-      // Move the trap basic blocks to the end of the function.
-      for (auto *FailBB : FailBBs) {
-        CurFn->splice(CurFn->end(), CurFn, FailBB->getIterator());
-      }
-    }
-  }
-
   //===--------------------------------------------------------------------===//
   // SIL instruction lowering
   //===--------------------------------------------------------------------===//
 
-  void visitSILBasicBlock(SILBasicBlock *BB);
+  bool shouldUseDispatchThunk(SILDeclRef method);
 
+  void visitSILBasicBlock(SILBasicBlock *BB);
   void emitErrorResultVar(CanSILFunctionType FnTy,
                           SILResultInfo ErrorInfo,
                           DebugValueInst *DbgValue);
   void emitPoisonDebugValueInst(DebugValueInst *i);
-  void emitDebugInfoForAllocStack(AllocStackInst *i, const TypeInfo &type,
-                                  llvm::Value *addr);
+  void emitDebugInfoBeforeAllocStack(AllocStackInst *i,
+                                     const TypeInfo &type,
+                                     DebugTypeInfo &DbgTy);
+  void emitDebugInfoAfterAllocStack(AllocStackInst *i,
+                                    const TypeInfo &type,
+                                    const DebugTypeInfo &DbgTy,
+                                    llvm::Value *addr);
   void visitAllocStackInst(AllocStackInst *i);
   void visitAllocPackInst(AllocPackInst *i);
   void visitAllocPackMetadataInst(AllocPackMetadataInst *i);
@@ -1246,9 +1238,6 @@ class IRGenSILFunction :
   void visitAssignInst(AssignInst *i) {
     llvm_unreachable("assign is not valid in canonical SIL");
   }
-  void visitAssignByWrapperInst(AssignByWrapperInst *i) {
-    llvm_unreachable("assign_by_wrapper is not valid in canonical SIL");
-  }
   void visitAssignOrInitInst(AssignOrInitInst *i) {
     llvm_unreachable("assign_or_init is not valid in canonical SIL");
   }
@@ -1351,6 +1340,7 @@ class IRGenSILFunction :
   void visitTupleElementAddrInst(TupleElementAddrInst *i);
   void visitStructExtractInst(StructExtractInst *i);
   void visitStructElementAddrInst(StructElementAddrInst *i);
+  void visitVectorBaseAddrInst(VectorBaseAddrInst *i);
   void visitRefElementAddrInst(RefElementAddrInst *i);
   void visitRefTailAddrInst(RefTailAddrInst *i);
 
@@ -1437,6 +1427,7 @@ class IRGenSILFunction :
   void visitIsUniqueInst(IsUniqueInst *i);
   void visitBeginCOWMutationInst(BeginCOWMutationInst *i);
   void visitEndCOWMutationInst(EndCOWMutationInst *i);
+  void visitEndCOWMutationAddrInst(EndCOWMutationAddrInst *i);
   void visitDestroyNotEscapedClosureInst(DestroyNotEscapedClosureInst *i);
   void visitDeallocStackInst(DeallocStackInst *i);
   void visitDeallocStackRefInst(DeallocStackRefInst *i);
@@ -1604,9 +1595,8 @@ Explosion NativeCCEntryPointArgumentEmission::explosionForObject(
     Address paramAddr =
         loadableParamTI.getAddressForPointer(paramExplosion.claimNext());
     if (loadableParamTI.getStorageType() != loadableArgTI.getStorageType())
-      paramAddr = loadableArgTI.getAddressForPointer(IGF.Builder.CreateBitCast(
-          paramAddr.getAddress(),
-          loadableArgTI.getStorageType()->getPointerTo()));
+      paramAddr = loadableArgTI.getAddressForPointer(
+          IGF.Builder.CreateBitCast(paramAddr.getAddress(), IGF.IGM.PtrTy));
     loadableArgTI.loadAsTake(IGF, paramAddr, paramValues);
   } else {
     if (!nativeSchema.empty()) {
@@ -1961,9 +1951,6 @@ IRGenSILFunction::IRGenSILFunction(IRGenModule &IGM, SILFunction *f)
 
 IRGenSILFunction::~IRGenSILFunction() {
   assert(Builder.hasPostTerminatorIP() && "did not terminate BB?!");
-  // Emit the fail BB if we have one.
-  if (!FailBBs.empty())
-    emitFailBB();
   LLVM_DEBUG(CurFn->print(llvm::dbgs()));
 }
 
@@ -1972,8 +1959,7 @@ static void emitPHINodesForType(IRGenSILFunction &IGF, SILType type,
                                 const TypeInfo &ti, unsigned predecessors,
                                 ValueVector &phis) {
   if (type.isAddress()) {
-    phis.push_back(IGF.Builder.CreatePHI(ti.getStorageType()->getPointerTo(),
-                                         predecessors));
+    phis.push_back(IGF.Builder.CreatePHI(IGF.IGM.PtrTy, predecessors));
   } else {
     // PHIs are always emitted with maximal explosion.
     ExplosionSchema schema = ti.getSchema();
@@ -1982,9 +1968,7 @@ static void emitPHINodesForType(IRGenSILFunction &IGF, SILType type,
         phis.push_back(
                    IGF.Builder.CreatePHI(elt.getScalarType(), predecessors));
       else
-        phis.push_back(
-                   IGF.Builder.CreatePHI(elt.getAggregateType()->getPointerTo(),
-                   predecessors));
+        phis.push_back(IGF.Builder.CreatePHI(IGF.IGM.PtrTy, predecessors));
     }
   }
 }
@@ -2048,6 +2032,11 @@ static ArrayRef<SILArgument *> emitEntryPointIndirectReturn(
   SILFunctionConventions fnConv(funcTy, IGF.getSILModule());
   SILType directResultType = IGF.CurSILFn->mapTypeIntoContext(
       fnConv.getSILResultType(IGF.IGM.getMaximalTypeExpansionContext()));
+
+  if (fnConv.hasGuaranteedAddressResult()) {
+    return entry->getArguments();
+  }
+
   if (requiresIndirectResult(directResultType)) {
     auto &paramTI = IGF.IGM.getTypeInfo(directResultType);
     auto &retTI =
@@ -2055,8 +2044,7 @@ static ArrayRef<SILArgument *> emitEntryPointIndirectReturn(
     auto ptr = emission.getIndirectResultForFormallyDirectResult();
     if (paramTI.getStorageType() != retTI.getStorageType()) {
       assert(directResultType.getASTType()->hasOpaqueArchetype());
-      ptr = IGF.Builder.CreateBitCast(ptr,
-                                      retTI.getStorageType()->getPointerTo());
+      ptr = IGF.Builder.CreateBitCast(ptr, IGF.IGM.PtrTy);
     }
     IGF.IndirectReturn = retTI.getAddressForPointer(ptr);
   }
@@ -2082,8 +2070,7 @@ static ArrayRef<SILArgument *> emitEntryPointIndirectReturn(
     if (paramTI.getStorageType() != retTI.getStorageType() || !isFixedSize) {
       assert(!isFixedSize ||
              inContextResultType.getASTType()->hasOpaqueArchetype());
-      ptr = IGF.Builder.CreateBitCast(ptr,
-                                      retTI.getStorageType()->getPointerTo());
+      ptr = IGF.Builder.CreateBitCast(ptr, IGF.IGM.PtrTy);
     }
     auto addr = retTI.getAddressForPointer(ptr);
     IGF.setLoweredAddress(ret, addr);
@@ -2123,8 +2110,7 @@ static void bindParameter(IRGenSILFunction &IGF,
   Explosion paramExplosion = explosionForArgument(index, 1);
   auto ptr = paramExplosion.claimNext();
   if (paramTI.getStorageType() != argTI.getStorageType()) {
-    ptr =
-        IGF.Builder.CreateBitCast(ptr, argTI.getStorageType()->getPointerTo());
+    ptr = IGF.Builder.CreateBitCast(ptr, IGF.IGM.PtrTy);
   }
   Address paramAddr = argTI.getAddressForPointer(ptr);
   IGF.setLoweredAddress(param, paramAddr);
@@ -2312,10 +2298,8 @@ static void emitEntryPointArgumentsNativeCC(IRGenSILFunction &IGF,
             [&](unsigned startIndex, unsigned size) {
               assert(size == 1);
               Explosion indicesTemp;
-              auto castedIndices = IGF.Builder.CreateBitCast(
-                  componentArgsBuf, IGF.getTypeInfo(indicesArg->getType())
-                                        .getStorageType()
-                                        ->getPointerTo());
+              auto castedIndices =
+                  IGF.Builder.CreateBitCast(componentArgsBuf, IGF.IGM.PtrTy);
               indicesTemp.add(castedIndices);
               return indicesTemp;
             });
@@ -2427,8 +2411,7 @@ static void emitEntryPointArgumentsCOrObjC(IRGenSILFunction &IGF,
     // Bitcast indirect argument pointers to the right storage type.
     if (arg->getType().isAddress()) {
       llvm::Value *ptr = params.claimNext();
-      ptr = IGF.Builder.CreateBitCast(ptr,
-                                      argTI.getStorageType()->getPointerTo());
+      ptr = IGF.Builder.CreateBitCast(ptr, IGF.IGM.PtrTy);
       IGF.setLoweredAddress(arg, Address(ptr, argTI.getStorageType(),
                                          argTI.getBestKnownAlignment()));
       continue;
@@ -3037,8 +3020,7 @@ void IRGenSILFunction::visitDifferentiabilityWitnessFunctionInst(
 
   auto fnType = cast<SILFunctionType>(i->getType().getASTType());
   Signature signature = IGM.getSignature(fnType);
-  diffWitness =
-      Builder.CreateBitCast(diffWitness, signature.getType()->getPointerTo());
+  diffWitness = Builder.CreateBitCast(diffWitness, IGM.PtrTy);
 
   setLoweredFunctionPointer(
       i, FunctionPointer::createUnsigned(fnType, diffWitness, signature, true));
@@ -3248,8 +3230,7 @@ void IRGenSILFunction::visitGlobalAddrInst(GlobalAddrInst *i) {
     SILType loweredTyInContext =
         var->getLoweredTypeInContext(getExpansionContext());
     auto &tiInContext = getTypeInfo(loweredTyInContext);
-    auto ptr = Builder.CreateBitOrPointerCast(
-        addr.getAddress(), tiInContext.getStorageType()->getPointerTo());
+    auto ptr = Builder.CreateBitOrPointerCast(addr.getAddress(), IGM.PtrTy);
     addr = Address(ptr, tiInContext.getStorageType(),
                    tiInContext.getBestKnownAlignment());
     return addr;
@@ -3298,9 +3279,8 @@ void IRGenSILFunction::visitGlobalValueInst(GlobalValueInst *i) {
 }
 
 void IRGenSILFunction::visitBaseAddrForOffsetInst(BaseAddrForOffsetInst *i) {
-  auto storagePtrTy = IGM.getStoragePointerType(i->getType());
   auto storageTy = IGM.getStorageType(i->getType());
-  llvm::Value *addr = llvm::ConstantPointerNull::get(storagePtrTy);
+  llvm::Value *addr = llvm::ConstantPointerNull::get(IGM.PtrTy);
   setLoweredAddress(i, Address(addr, storageTy, Alignment()));
 }
 
@@ -3860,6 +3840,10 @@ void IRGenSILFunction::visitFullApplySite(FullApplySite site) {
     }
   }
 
+  // Lower the arguments and return value in the callee's generic context.
+  GenericContextScope scope(IGM,
+                            origCalleeType->getInvocationGenericSignature());
+
   Explosion llArgs;
   WitnessMetadata witnessMetadata;
   auto emission = getCallEmissionForLoweredValue(
@@ -3872,9 +3856,6 @@ void IRGenSILFunction::visitFullApplySite(FullApplySite site) {
 
   emission->begin();
 
-  // Lower the arguments and return value in the callee's generic context.
-  GenericContextScope scope(IGM, origCalleeType->getInvocationGenericSignature());
-
   auto &calleeFP = emission->getCallee().getFunctionPointer();
 
   // Allocate space for the coroutine buffer.
@@ -3958,7 +3939,11 @@ void IRGenSILFunction::visitFullApplySite(FullApplySite site) {
 
   // For a simple apply, just bind the apply result to the result of the call.
   if (auto apply = dyn_cast<ApplyInst>(i)) {
-    setLoweredExplosion(apply, result);
+    if (apply->hasGuaranteedAddressResult()) {
+      setCorrespondingLoweredValues(apply->getResults(), result);
+    } else {
+      setLoweredExplosion(apply, result);
+    }
     emission->end();
 
   // For begin_apply, we have to destructure the call.
@@ -4475,6 +4460,16 @@ static void emitReturnInst(IRGenSILFunction &IGF,
     return;
   }
 
+  if (conv.hasGuaranteedAddressResult()) {
+    assert(IGF.CurSILFn->getLoweredFunctionType()->getLanguage() ==
+           SILFunctionLanguage::Swift);
+    auto funcResultType = IGF.CurSILFn->mapTypeIntoContext(
+        conv.getSILResultType(IGF.IGM.getMaximalTypeExpansionContext()));
+
+    emitGuaranteedAddressResult(IGF, result, funcResultType, resultTy);
+    return;
+  }
+
   // The invariant on the out-parameter is that it's always zeroed, so
   // there's nothing to do here.
 
@@ -4786,15 +4781,18 @@ void IRGenSILFunction::visitEndApply(BeginApplyInst *i, EndApplyInst *ei) {
   const auto &coroutine = getLoweredCoroutine(i->getTokenResult());
   bool isAbort = ei == nullptr;
 
-  auto sig = Signature::forCoroutineContinuation(IGM, i->getOrigCalleeType());
+  // Lower the return value in the callee's generic context.
+  auto origCalleeType = i->getOrigCalleeType();
+  GenericContextScope scope(IGM, origCalleeType->getInvocationGenericSignature());
+
+  auto sig = Signature::forCoroutineContinuation(IGM, origCalleeType);
 
   // Cast the continuation pointer to the right function pointer type.
   auto continuation = coroutine.Continuation;
-  continuation = Builder.CreateBitCast(continuation,
-                                       sig.getType()->getPointerTo());
+  continuation = Builder.CreateBitCast(continuation, IGM.PtrTy);
 
   auto schemaAndEntity =
-    getCoroutineResumeFunctionPointerAuth(IGM, i->getOrigCalleeType());
+    getCoroutineResumeFunctionPointerAuth(IGM, origCalleeType);
   auto pointerAuth = PointerAuthInfo::emit(*this, schemaAndEntity.first,
                                            coroutine.getBuffer().getAddress(),
                                            schemaAndEntity.second);
@@ -4823,16 +4821,15 @@ void IRGenSILFunction::visitEndApply(BeginApplyInst *i, EndApplyInst *ei) {
 
   if (!isAbort) {
     auto resultType = call->getType();
+    Explosion e;
     if (!resultType->isVoidTy()) {
-      Explosion e;
       // FIXME: Do we need to handle ABI-related conversions here?
       // It seems we cannot have C function convention for coroutines, etc.
       extractScalarResults(*this, resultType, call, e);
-      
-      // NOTE: This inserts a new entry into the LoweredValues DenseMap,
-      // invalidating the reference held by `coroutine`.
-      setLoweredExplosion(ei, e);
     }
+    // NOTE: This inserts a new entry into the LoweredValues DenseMap,
+    // invalidating the reference held by `coroutine`.    
+    setLoweredExplosion(ei, e);
   }
 }
 
@@ -5361,8 +5358,7 @@ void IRGenSILFunction::visitDynamicMethodBranchInst(DynamicMethodBranchInst *i){
   };
   auto respondsToSelectorTy = llvm::FunctionType::get(IGM.Int1Ty, argTys,
                                                       /*isVarArg*/ false);
-  messenger = llvm::ConstantExpr::getBitCast(
-      messenger, respondsToSelectorTy->getPointerTo());
+  messenger = llvm::ConstantExpr::getBitCast(messenger, IGM.PtrTy);
   llvm::CallInst *call = Builder.CreateCall(
       respondsToSelectorTy, messenger, {object, respondsToSelector, loadSel});
   call->setDoesNotThrow();
@@ -5636,6 +5632,13 @@ void IRGenSILFunction::visitStructElementAddrInst(
   setLoweredAddress(i, field);
 }
 
+void IRGenSILFunction::visitVectorBaseAddrInst(VectorBaseAddrInst *i) {
+  auto addr = getLoweredAddress(i->getVector());
+  auto &ti = getTypeInfo(i->getType());
+  auto result = Builder.CreateElementBitCast(addr, ti.getStorageType());
+  setLoweredAddress(i, result);
+}
+
 void IRGenSILFunction::visitRefElementAddrInst(swift::RefElementAddrInst *i) {
   Explosion base = getLoweredExplosion(i->getOperand());
   llvm::Value *value = base.claimNext();
@@ -5763,7 +5766,7 @@ static Address isSafeForMemCpyPeephole(const TypeInfo &TI, SILArgument *arg,
     return Address();
   }
 
-  lifetimeBegin->moveBefore(load);
+  lifetimeBegin->moveBefore(load->getIterator());
 
   // Set insertPt to the first load such that we are within the lifetime of the
   // alloca marked by the lifetime intrinsic.
@@ -6364,6 +6367,10 @@ void IRGenSILFunction::visitEndCOWMutationInst(EndCOWMutationInst *i) {
   setLoweredExplosion(i, v);
 }
 
+void IRGenSILFunction::visitEndCOWMutationAddrInst(EndCOWMutationAddrInst *i) {
+  // end_cow_mutation_addr is purely for SIL.
+}
+
 void IRGenSILFunction::visitDestroyNotEscapedClosureInst(
     swift::DestroyNotEscapedClosureInst *i) {
   // The closure operand is allowed to be an optional closure.
@@ -6395,14 +6402,52 @@ void IRGenSILFunction::visitDestroyNotEscapedClosureInst(
   setLoweredExplosion(i, out);
 }
 
-void IRGenSILFunction::emitDebugInfoForAllocStack(AllocStackInst *i,
-                                                  const TypeInfo &type,
-                                                  llvm::Value *addr) {
+void IRGenSILFunction::emitDebugInfoBeforeAllocStack(AllocStackInst *i,
+                                                     const TypeInfo &type,
+                                                     DebugTypeInfo &DbgTy) {
   auto VarInfo = i->getVarInfo();
-  if (!VarInfo)
+  if (!VarInfo ||
+      !i->getDebugScope() ||
+      i->getDebugScope()->getInlinedFunction()->isTransparent())
+    return;
+
+  VarDecl *Decl = i->getDecl();
+
+  SILType SILTy;
+  if (auto MaybeSILTy = VarInfo->Type) {
+    // If there is auxiliary type info, use it
+    SILTy = *MaybeSILTy;
+  } else {
+    SILTy = i->getType();
+  }
+  auto RealType = SILTy.getASTType();
+  if (Decl) {
+    DbgTy = DebugTypeInfo::getLocalVariable(Decl, RealType, type, IGM);
+  } else if (i->getFunction()->isBare() && !SILTy.hasArchetype() &&
+             !VarInfo->Name.empty()) {
+    DbgTy = DebugTypeInfo::getFromTypeInfo(RealType, getTypeInfo(SILTy), IGM);
+  } else
+    return;
+
+  bindArchetypes(DbgTy.getType());
+}
+
+/// Do not instantiate type metadata in here, since this may allocate on-stack
+/// packs which will then be cleaned up in the wrong order with respect to the
+/// value stack allocation.
+void IRGenSILFunction::emitDebugInfoAfterAllocStack(AllocStackInst *i,
+                                                    const TypeInfo &type,
+                                                    const DebugTypeInfo &DbgTy,
+                                                    llvm::Value *addr) {
+  auto VarInfo = i->getVarInfo();
+  if (!VarInfo ||
+      !i->getDebugScope() ||
+      i->getDebugScope()->getInlinedFunction()->isTransparent())
     return;
 
   VarDecl *Decl = i->getDecl();
+  auto *DS = i->getDebugScope();
+
   // Describe the underlying alloca. This way an llvm.dbg.declare intrinsic
   // is used, which is valid for the entire lifetime of the alloca.
   if (auto *BitCast = dyn_cast<llvm::BitCastInst>(addr)) {
@@ -6419,13 +6464,6 @@ void IRGenSILFunction::emitDebugInfoForAllocStack(AllocStackInst *i,
       (void)isTaskAlloc;
     }
   }
-
-  auto DS = i->getDebugScope();
-  if (!DS)
-    return;
-
-  if (i->getDebugScope()->getInlinedFunction()->isTransparent())
-    return;
   
   bool IsAnonymous = false;
   VarInfo->Name = getVarName(i, IsAnonymous);
@@ -6460,25 +6498,15 @@ void IRGenSILFunction::emitDebugInfoForAllocStack(AllocStackInst *i,
     }
   }
 
-  SILType SILTy;
-  if (auto MaybeSILTy = VarInfo->Type) {
-    // If there is auxiliary type info, use it
-    SILTy = *MaybeSILTy;
-  } else {
-    SILTy = i->getType();
-  }
-  auto RealType = SILTy.getASTType();
-  DebugTypeInfo DbgTy;
-  if (Decl) {
-    DbgTy = DebugTypeInfo::getLocalVariable(Decl, RealType, type, IGM);
-  } else if (i->getFunction()->isBare() && !SILTy.hasArchetype() &&
-             !VarInfo->Name.empty()) {
-    DbgTy = DebugTypeInfo::getFromTypeInfo(RealType, getTypeInfo(SILTy), IGM);
-  } else
-    return;
+  if (DbgTy.getType() && IGM.DebugInfo) {
+    SILType SILTy;
+    if (auto MaybeSILTy = VarInfo->Type) {
+      // If there is auxiliary type info, use it
+      SILTy = *MaybeSILTy;
+    } else {
+      SILTy = i->getType();
+    }
 
-  bindArchetypes(DbgTy.getType());
-  if (IGM.DebugInfo) {
     emitDebugVariableDeclaration(
         addr, DbgTy, SILTy, DS, i->getLoc(), *VarInfo, Indirection,
         AddrDbgInstrKind(i->usesMoveableValueDebugInfo()));
@@ -6496,6 +6524,9 @@ void IRGenSILFunction::visitAllocStackInst(swift::AllocStackInst *i) {
   dbgname = getVarName(i, IsAnonymous);
 # endif
 
+  DebugTypeInfo DbgTy;
+  emitDebugInfoBeforeAllocStack(i, type, DbgTy);
+
   auto stackAddr = type.allocateStack(*this, i->getElementType(), dbgname);
   setLoweredStackAddress(i, stackAddr);
   Address addr = stackAddr.getAddress();
@@ -6510,7 +6541,7 @@ void IRGenSILFunction::visitAllocStackInst(swift::AllocStackInst *i) {
         Ty->getStructOrBoundGenericStruct())
       zeroInit(dyn_cast<llvm::AllocaInst>(addr.getAddress()));
   }
-  emitDebugInfoForAllocStack(i, type, addr.getAddress());
+  emitDebugInfoAfterAllocStack(i, type, DbgTy, addr.getAddress());
 }
 
 void IRGenSILFunction::visitAllocPackInst(swift::AllocPackInst *i) {
@@ -7133,9 +7164,8 @@ void IRGenSILFunction::visitPointerToAddressInst(swift::PointerToAddressInst *i)
   llvm::Value *ptrValue = from.claimNext();
 
   auto &ti = getTypeInfo(i->getType());
-  
-  llvm::Type *destType = ti.getStorageType()->getPointerTo();
-  ptrValue = Builder.CreateBitCast(ptrValue, destType);
+
+  ptrValue = Builder.CreateBitCast(ptrValue, IGM.PtrTy);
 
   if (i->alignment())
     setLoweredAddress(i, Address(ptrValue, ti.getStorageType(),
@@ -7187,7 +7217,7 @@ visitUncheckedRefCastAddrInst(swift::UncheckedRefCastAddrInst *i) {
                   dest, i->getTargetFormalType(),
                   CastConsumptionKind::TakeAlways,
                   CheckedCastMode::Unconditional,
-                  CastingIsolatedConformances::Allow);
+                  CheckedCastInstOptions());
 }
 
 void IRGenSILFunction::visitUncheckedAddrCastInst(
@@ -7417,7 +7447,7 @@ void IRGenSILFunction::visitUnconditionalCheckedCastInst(
                         i->getTargetLoweredType(),
                         i->getTargetFormalType(),
                         CheckedCastMode::Unconditional,
-                        i->getIsolatedConformances(),
+                        i->getCheckedCastOptions(),
                         ex);
   setLoweredExplosion(i, ex);
 }
@@ -7607,7 +7637,7 @@ void IRGenSILFunction::visitUnconditionalCheckedCastAddrInst(
                   dest, i->getTargetFormalType(),
                   CastConsumptionKind::TakeAlways,
                   CheckedCastMode::Unconditional,
-                  i->getIsolatedConformances());
+                  i->getCheckedCastOptions());
 }
 
 void IRGenSILFunction::visitCheckedCastBranchInst(
@@ -7628,7 +7658,7 @@ void IRGenSILFunction::visitCheckedCastBranchInst(
                           i->getTargetLoweredType(),
                           i->getTargetFormalType(),
                           CheckedCastMode::Conditional,
-                          i->getIsolatedConformances(),
+                          i->getCheckedCastOptions(),
                           ex);
     auto val = ex.claimNext();
     castResult.casted = val;
@@ -7667,7 +7697,7 @@ void IRGenSILFunction::visitCheckedCastAddrBranchInst(
                     src, i->getSourceFormalType(),
                     dest, i->getTargetFormalType(),
                     i->getConsumptionKind(), CheckedCastMode::Conditional,
-                    i->getIsolatedConformances());
+                    i->getCheckedCastOptions());
   Builder.CreateCondBr(castSucceeded,
                        getLoweredBB(i->getSuccessBB()).bb,
                        getLoweredBB(i->getFailureBB()).bb);
@@ -7757,8 +7787,8 @@ void IRGenSILFunction::visitKeyPathInst(swift::KeyPathInst *I) {
       auto &ti = getTypeInfo(operand->getType());
       auto ptr = Builder.CreateInBoundsGEP(IGM.Int8Ty, argsBuf.getAddress(),
                                            operandOffsets[i]);
-      auto addr = ti.getAddressForPointer(
-        Builder.CreateBitCast(ptr, ti.getStorageType()->getPointerTo()));
+      auto addr =
+          ti.getAddressForPointer(Builder.CreateBitCast(ptr, IGM.PtrTy));
       if (operand->getType().isAddress()) {
         ti.initializeWithTake(*this, addr, getLoweredAddress(operand),
                               operand->getType(), false,
@@ -8250,35 +8280,7 @@ void IRGenSILFunction::visitDestroyAddrInst(swift::DestroyAddrInst *i) {
 void IRGenSILFunction::visitCondFailInst(swift::CondFailInst *i) {
   Explosion e = getLoweredExplosion(i->getOperand());
   llvm::Value *cond = e.claimNext();
-
-  // The condition should be false, or we die.
-  auto expectedCond = Builder.CreateExpect(cond,
-                                         llvm::ConstantInt::get(IGM.Int1Ty, 0));
-  
-  // Emit individual fail blocks so that we can map the failure back to a source
-  // line.
-  auto origInsertionPoint = Builder.GetInsertBlock();
-
-  llvm::BasicBlock *failBB = llvm::BasicBlock::Create(IGM.getLLVMContext());
-  llvm::BasicBlock *contBB = llvm::BasicBlock::Create(IGM.getLLVMContext());
-  auto br = Builder.CreateCondBr(expectedCond, failBB, contBB);
-
-  if (IGM.getOptions().AnnotateCondFailMessage && !i->getMessage().empty())
-    br->addAnnotationMetadata(i->getMessage());
-
-  Builder.SetInsertPoint(&CurFn->back());
-  Builder.emitBlock(failBB);
-  if (IGM.DebugInfo)
-    // If we are emitting DWARF, this does nothing. Otherwise the ``llvm.trap``
-    // instruction emitted from ``Builtin.condfail`` should have an inlined
-    // debug location. This is because zero is not an artificial line location
-    // in CodeView.
-    IGM.DebugInfo->setInlinedTrapLocation(Builder, i->getDebugScope());
-  emitTrap(i->getMessage(), /*EmitUnreachable=*/true);
-  
-  Builder.SetInsertPoint(origInsertionPoint);
-  Builder.emitBlock(contBB);
-  FailBBs.push_back(failBB);
+  emitConditionalTrap(cond, i->getMessage(), i->getDebugScope());
 }
 
 void IRGenSILFunction::visitIncrementProfilerCounterInst(
@@ -8382,7 +8384,7 @@ void IRGenSILFunction::visitSuperMethodInst(swift::SuperMethodInst *i) {
 
     // The function returns an i8*; cast it to the correct type.
     auto sig = IGM.getSignature(methodType);
-    fnPtr = Builder.CreateBitCast(fnPtr, sig.getType()->getPointerTo());
+    fnPtr = Builder.CreateBitCast(fnPtr, IGM.PtrTy);
 
     auto &schema = methodType->isAsync()
                        ? getOptions().PointerAuth.AsyncSwiftClassMethodPointers
@@ -8414,28 +8416,17 @@ void IRGenSILFunction::visitObjCSuperMethodInst(swift::ObjCSuperMethodInst *i) {
                               /*startAtSuper=*/true);
 }
 
-void IRGenSILFunction::visitClassMethodInst(swift::ClassMethodInst *i) {
-  assert(!i->getMember().isForeign);
-
-  Explosion base = getLoweredExplosion(i->getOperand());
-  llvm::Value *baseValue = base.claimNext();
-
-  SILDeclRef method = i->getMember().getOverriddenVTableEntry();
-  PrettyStackTraceSILDeclRef entry("lowering class method call to", method);
-
-  auto methodType = i->getType().castTo<SILFunctionType>();
-
+bool IRGenSILFunction::shouldUseDispatchThunk(SILDeclRef method) {
   AccessLevel methodAccess = method.getDecl()->getEffectiveAccess();
   auto *classDecl = cast<ClassDecl>(method.getDecl()->getDeclContext());
   bool shouldUseDispatchThunk = false;
   // Because typechecking for the debugger has more lax rules, check the access
   // level of the getter to decide whether to use a dispatch thunk for the
   // debugger.
-  bool shouldUseDispatchThunkIfInDebugger =
-      !classDecl->getASTContext().LangOpts.DebuggerSupport ||
-      methodAccess == AccessLevel::Public;
+  bool inDebugger = classDecl->getASTContext().LangOpts.DebuggerSupport;
+  bool shouldUseDispatchThunkIfInDebugger = methodAccess >= AccessLevel::Public;
   if (IGM.hasResilientMetadata(classDecl, ResilienceExpansion::Maximal) &&
-      shouldUseDispatchThunkIfInDebugger) {
+      (!inDebugger || shouldUseDispatchThunkIfInDebugger)) {
     shouldUseDispatchThunk = true;
   } else if (IGM.getOptions().VirtualFunctionElimination) {
     // For VFE, use a thunk if the target class is in another module. This
@@ -8452,9 +8443,22 @@ void IRGenSILFunction::visitClassMethodInst(swift::ClassMethodInst *i) {
     shouldUseDispatchThunk =
         classDecl->getModuleContext() != IGM.getSwiftModule();
   }
+  return shouldUseDispatchThunk;
+}
 
-  if (shouldUseDispatchThunk) {
-    llvm::Constant *fnPtr = IGM.getAddrOfDispatchThunk(method, NotForDefinition);
+void IRGenSILFunction::visitClassMethodInst(swift::ClassMethodInst *i) {
+  assert(!i->getMember().isForeign);
+
+  Explosion base = getLoweredExplosion(i->getOperand());
+  llvm::Value *baseValue = base.claimNext();
+
+  SILDeclRef method = i->getMember().getOverriddenVTableEntry();
+  PrettyStackTraceSILDeclRef entry("lowering class method call to", method);
+
+  auto methodType = i->getType().castTo<SILFunctionType>();
+  if (shouldUseDispatchThunk(method)) {
+    llvm::Constant *fnPtr =
+        IGM.getAddrOfDispatchThunk(method, NotForDefinition);
 
     if (methodType->isAsync()) {
       auto *fnPtrType = fnPtr->getType();
diff --git a/lib/IRGen/IRSymbolVisitor.cpp b/lib/IRGen/IRSymbolVisitor.cpp
index 3a4b943bb45d1..ff249fccf3b45 100644
--- a/lib/IRGen/IRSymbolVisitor.cpp
+++ b/lib/IRGen/IRSymbolVisitor.cpp
@@ -109,14 +109,6 @@ class IRSymbolVisitorImpl : public SILSymbolVisitor {
   void addDispatchThunk(SILDeclRef declRef) override {
     auto entity = LinkEntity::forDispatchThunk(declRef);
 
-    // TODO: explain why
-    if (declRef.isDistributedThunk()) {
-      auto afd = declRef.getAbstractFunctionDecl();
-      if (afd && isa<ProtocolDecl>(afd->getDeclContext())) {
-        return;
-      }
-    }
-
     addLinkEntity(entity);
 
     if (declRef.getAbstractFunctionDecl()->hasAsync())
@@ -166,14 +158,6 @@ class IRSymbolVisitorImpl : public SILSymbolVisitor {
   }
 
   void addMethodDescriptor(SILDeclRef declRef) override {
-    if (declRef.isDistributedThunk()) {
-      auto afd = declRef.getAbstractFunctionDecl();
-      auto DC = afd->getDeclContext();
-      if (isa<ProtocolDecl>(DC)) {
-        return;
-      }
-    }
-
     addLinkEntity(LinkEntity::forMethodDescriptor(declRef));
   }
 
diff --git a/lib/IRGen/Linking.cpp b/lib/IRGen/Linking.cpp
index 0a2559f425810..e9323b7285576 100644
--- a/lib/IRGen/Linking.cpp
+++ b/lib/IRGen/Linking.cpp
@@ -82,19 +82,16 @@ bool swift::irgen::useDllStorage(const llvm::Triple &triple) {
 UniversalLinkageInfo::UniversalLinkageInfo(IRGenModule &IGM)
     : UniversalLinkageInfo(IGM.Triple, IGM.IRGen.hasMultipleIGMs(),
                            IGM.IRGen.Opts.ForcePublicLinkage,
-                           IGM.IRGen.Opts.InternalizeSymbols,
-                           IGM.IRGen.Opts.MergeableSymbols) {}
+                           IGM.IRGen.Opts.InternalizeSymbols) {}
 
 UniversalLinkageInfo::UniversalLinkageInfo(const llvm::Triple &triple,
                                            bool hasMultipleIGMs,
                                            bool forcePublicDecls,
-                                           bool isStaticLibrary,
-                                           bool mergeableSymbols)
+                                           bool isStaticLibrary)
     : IsELFObject(triple.isOSBinFormatELF()),
       IsMSVCEnvironment(triple.isWindowsMSVCEnvironment()),
       UseDLLStorage(useDllStorage(triple)), Internalize(isStaticLibrary),
-      HasMultipleIGMs(hasMultipleIGMs), ForcePublicDecls(forcePublicDecls),
-      MergeableSymbols(mergeableSymbols) {}
+      HasMultipleIGMs(hasMultipleIGMs), ForcePublicDecls(forcePublicDecls) {}
 
 LinkEntity LinkEntity::forSILGlobalVariable(SILGlobalVariable *G,
                                             IRGenModule &IGM) {
@@ -1147,7 +1144,7 @@ llvm::Type *LinkEntity::getDefaultDeclarationType(IRGenModule &IGM) const {
   case Kind::ProtocolWitnessTableLazyCacheVariable:
     return IGM.WitnessTablePtrTy;
   case Kind::SILFunction:
-    return IGM.FunctionPtrTy->getPointerTo();
+    return IGM.PtrTy;
   case Kind::MethodDescriptor:
   case Kind::MethodDescriptorInitializer:
   case Kind::MethodDescriptorAllocator:
@@ -1734,3 +1731,38 @@ bool LinkEntity::isAlwaysSharedLinkage() const {
     return false;
   }
 }
+
+bool LinkEntity::hasNonUniqueDefinition() const {
+  if (isDeclKind(getKind())) {
+    auto decl = getDecl();
+    return SILDeclRef::declHasNonUniqueDefinition(decl);
+  }
+
+  if (hasSILFunction()) {
+    return getSILFunction()->hasNonUniqueDefinition();
+  }
+
+  if (getKind() == Kind::SILGlobalVariable ||
+      getKind() == Kind::ReadOnlyGlobalObject)
+    return getSILGlobalVariable()->hasNonUniqueDefinition();
+
+  if (getKind() == Kind::TypeMetadata) {
+    // For a nominal type, check its declaration.
+    CanType type = getType();
+    if (auto nominal = type->getAnyNominal()) {
+      return SILDeclRef::declHasNonUniqueDefinition(nominal);
+    }
+
+    // All other type metadata is nonuniqued.
+    return true;
+  }
+
+  // Always treat witness tables as having non-unique definitions.
+  if (getKind() == Kind::ProtocolWitnessTable) {
+    if (auto context = getDeclContextForEmission())
+      if (context->getParentModule()->getASTContext().LangOpts.hasFeature(Feature::Embedded))
+        return true;
+  }
+
+  return false;
+}
diff --git a/lib/IRGen/LoadableByAddress.cpp b/lib/IRGen/LoadableByAddress.cpp
index 11adbef00f09d..042d8e5b5893e 100644
--- a/lib/IRGen/LoadableByAddress.cpp
+++ b/lib/IRGen/LoadableByAddress.cpp
@@ -375,12 +375,14 @@ static bool modResultType(SILFunction *F, irgen::IRGenModule &Mod,
 static bool shouldTransformYields(GenericEnvironment *genEnv,
                                   CanSILFunctionType loweredTy,
                                   irgen::IRGenModule &Mod,
-                                  LargeSILTypeMapper &Mapper) {
+                                  LargeSILTypeMapper &Mapper,
+                                  TypeExpansionContext expansion) {
   if (!modifiableFunction(loweredTy)) {
     return false;
   }
   for (auto &yield : loweredTy->getYields()) {
-    auto yieldStorageType = yield.getSILStorageInterfaceType();
+    auto yieldStorageType = yield.getSILStorageType(Mod.getSILModule(),
+                                                    loweredTy, expansion);
     auto newYieldStorageType =
         Mapper.getNewSILType(genEnv, yieldStorageType, Mod);
     if (yieldStorageType != newYieldStorageType)
@@ -394,7 +396,8 @@ static bool modYieldType(SILFunction *F, irgen::IRGenModule &Mod,
   GenericEnvironment *genEnv = getSubstGenericEnvironment(F);
   auto loweredTy = F->getLoweredFunctionType();
 
-  return shouldTransformYields(genEnv, loweredTy, Mod, Mapper);
+  return shouldTransformYields(genEnv, loweredTy, Mod, Mapper,
+                               F->getTypeExpansionContext());
 }
 
 SILParameterInfo LargeSILTypeMapper::getNewParameter(GenericEnvironment *env,
@@ -3574,6 +3577,7 @@ void LargeLoadableHeuristic::propagate(PostOrderFunctionInfo &po) {
   for (auto *BB : po.getPostOrder()) {
     for (auto &I : llvm::reverse(*BB)) {
       switch (I.getKind()) {
+      case SILInstructionKind::UncheckedBitwiseCastInst:
       case SILInstructionKind::TupleExtractInst:
       case SILInstructionKind::StructExtractInst: {
         auto &proj = cast<SingleValueInstruction>(I);
@@ -3923,6 +3927,13 @@ void AddressAssignment::finish(DominanceInfo *dominance,
   StackNesting::fixNesting(&currFn);
 }
 
+static bool isSoleUserOf(LoadInst *load, SILInstruction *next) {
+  if (!load->hasOneUse())
+    return false;
+  if(load->getSingleUse()->getUser() != next)
+    return false;
+  return true;
+}
 namespace {
 class AssignAddressToDef : SILInstructionVisitor<AssignAddressToDef> {
   friend SILVisitorBase<AssignAddressToDef>;
@@ -3980,6 +3991,14 @@ class AssignAddressToDef : SILInstructionVisitor<AssignAddressToDef> {
     singleValueInstructionFallback(kp);
   }
 
+  void visitEndCOWMutationInst(EndCOWMutationInst *endCOW) {
+    // This instruction is purely for semantic tracking in SIL.
+    // Simply forward the value and delete the instruction.
+    auto valAddr = assignment.getAddressForValue(endCOW->getOperand());
+    assignment.mapValueToAddress(endCOW, valAddr);
+    assignment.markForDeletion(endCOW);
+  }
+
   void visitMarkDependenceInst(MarkDependenceInst *mark) {
     // This instruction is purely for semantic tracking in SIL.
     // Simply forward the value and delete the instruction.
@@ -4024,6 +4043,14 @@ class AssignAddressToDef : SILInstructionVisitor<AssignAddressToDef> {
   }
 
   void visitLoadInst(LoadInst *load) {
+    // Forward the address of the load if its sole user immediately follows the
+    // load instructions.
+    if (isSoleUserOf(load, &*++load->getIterator())) {
+      assignment.markForDeletion(load);
+      assignment.mapValueToAddress(origValue, load->getOperand());
+      return;
+    }
+
     auto builder = assignment.getBuilder(load->getIterator());
     auto addr = assignment.createAllocStack(load->getType());
 
@@ -4452,22 +4479,35 @@ class RewriteUser : SILInstructionVisitor<RewriteUser> {
 
   void visitSwitchEnumInst(SwitchEnumInst *sw) {
     auto opdAddr = assignment.getAddressForValue(sw->getOperand());
-    {
+    // UncheckedTakeEnumDataAddr is destructive. If we have a used switch target
+    // block argument we need to provide for a destructible location for the
+    // UncheckedTakeEnumDataAddr.
+    SILValue destructibleAddress;
+    auto initDestructibleAddress = [&] () -> void{
+      if (destructibleAddress)
+        return;
       auto addr = assignment.createAllocStack(sw->getOperand()->getType());
       // UncheckedTakeEnumDataAddr is destructive.
       // So we need to copy to keep the original address location valid.
       auto builder = assignment.getBuilder(sw->getIterator());
       builder.createCopyAddr(sw->getLoc(), opdAddr, addr, IsTake,
                              IsInitialization);
-      opdAddr = addr;
-    }
+      destructibleAddress = addr;
+    };
 
     auto loc = sw->getLoc();
 
     auto rewriteCase = [&](EnumElementDecl *caseDecl, SILBasicBlock *caseBB) {
       // Nothing to do for unused case payloads.
-      if (caseBB->getArguments().size() == 0)
+      if (caseBB->getArguments().size() == 0 ||
+          caseBB->getArguments()[0]->use_empty()) {
+        if (caseBB->getArguments().size()) {
+          assignment.markBlockArgumentForDeletion(caseBB);
+        }
         return;
+      }
+
+      initDestructibleAddress();
 
       assert(caseBB->getArguments().size() == 1);
       SILArgument *caseArg = caseBB->getArgument(0);
@@ -4476,8 +4516,10 @@ class RewriteUser : SILInstructionVisitor<RewriteUser> {
 
       SILBuilder caseBuilder = assignment.getBuilder(caseBB->begin());
       auto *caseAddr =
-        caseBuilder.createUncheckedTakeEnumDataAddr(loc, opdAddr, caseDecl,
-                                                    caseArg->getType().getAddressType());
+        caseBuilder.createUncheckedTakeEnumDataAddr(loc, destructibleAddress,
+                                           caseDecl,
+                                           caseArg->getType().getAddressType());
+
       if (assignment.isLargeLoadableType(caseArg->getType())) {
         assignment.mapValueToAddress(caseArg, caseAddr);
         assignment.markBlockArgumentForDeletion(caseBB);
diff --git a/lib/IRGen/LocalTypeData.cpp b/lib/IRGen/LocalTypeData.cpp
index 048d3ea077126..4653b2f9e8ee7 100644
--- a/lib/IRGen/LocalTypeData.cpp
+++ b/lib/IRGen/LocalTypeData.cpp
@@ -735,11 +735,20 @@ void LocalTypeDataCache::addAbstractForTypeMetadata(IRGenFunction &IGF,
   // Look for anything at all that's fulfilled by this.  If we don't find
   // anything, stop.
   FulfillmentMap fulfillments;
-  if (!fulfillments.searchTypeMetadata(IGF.IGM, type, isExact,
-                                       metadata.getStaticLowerBoundOnState(),
-                                       /*source*/ 0, MetadataPath(),
-                                       callbacks)) {
-    return;
+  if (auto tupleType = dyn_cast<TupleType>(type)) {
+    if (!fulfillments.searchTupleTypeMetadata(IGF.IGM, tupleType, isExact,
+                                              metadata.getStaticLowerBoundOnState(),
+                                              /*source*/ 0, MetadataPath(),
+                                              callbacks)) {
+      return;
+    }
+  } else {
+    if (!fulfillments.searchTypeMetadata(IGF.IGM, type, isExact,
+                                         metadata.getStaticLowerBoundOnState(),
+                                         /*source*/ 0, MetadataPath(),
+                                         callbacks)) {
+      return;
+    }
   }
 
   addAbstractForFulfillments(IGF, std::move(fulfillments),
diff --git a/lib/IRGen/LocalTypeDataKind.h b/lib/IRGen/LocalTypeDataKind.h
index a816daa62c44a..47cdf2b89d173 100644
--- a/lib/IRGen/LocalTypeDataKind.h
+++ b/lib/IRGen/LocalTypeDataKind.h
@@ -117,19 +117,19 @@ class LocalTypeDataKind {
   /// same function.
   static LocalTypeDataKind
   forAbstractProtocolWitnessTable(ProtocolDecl *protocol) {
-    assert(protocol && "protocol reference may not be null");
+    ASSERT(protocol && "protocol reference may not be null");
     return LocalTypeDataKind(uintptr_t(protocol) | Kind_Decl);
   }
 
   /// A reference to a protocol witness table for a concrete type.
   static LocalTypeDataKind
   forConcreteProtocolWitnessTable(ProtocolConformance *conformance) {
-    assert(conformance && "conformance reference may not be null");
+    ASSERT(conformance && "conformance reference may not be null");
     return LocalTypeDataKind(uintptr_t(conformance) | Kind_Conformance);
   }
 
   static LocalTypeDataKind forProtocolWitnessTablePack(PackConformance *pack) {
-    assert(pack && "pack conformance reference may not be null");
+    ASSERT(pack && "pack conformance reference may not be null");
     return LocalTypeDataKind(uintptr_t(pack) | Kind_PackConformance);
   }
 
diff --git a/lib/IRGen/MetadataRequest.cpp b/lib/IRGen/MetadataRequest.cpp
index e820db5b9bd77..e814067daf1f0 100644
--- a/lib/IRGen/MetadataRequest.cpp
+++ b/lib/IRGen/MetadataRequest.cpp
@@ -264,41 +264,6 @@ MetadataDependency MetadataDependencyCollector::finish(IRGenFunction &IGF) {
   return result;
 }
 
-static bool usesExtendedExistentialMetadata(CanType type) {
-  auto layout = type.getExistentialLayout();
-  // If there are parameterized protocol types that we want to
-  // treat as equal to unparameterized protocol types (maybe
-  // something like `P<some Any>`?), then AST type canonicalization
-  // should turn them into unparameterized protocol types.  If the
-  // structure makes it to IRGen, we have to honor that decision that
-  // they represent different types.
-  return !layout.getParameterizedProtocols().empty();
-}
-
-static std::optional<std::pair<CanExistentialType, /*depth*/ unsigned>>
-usesExtendedExistentialMetadata(CanExistentialMetatypeType type) {
-  unsigned depth = 1;
-  auto cur = type.getInstanceType();
-  while (auto metatype = dyn_cast<ExistentialMetatypeType>(cur)) {
-    cur = metatype.getInstanceType();
-    depth++;
-  }
-
-  // The only existential types that don't currently use ExistentialType
-  // are Any and AnyObject, which don't use extended metadata.
-  if (usesExtendedExistentialMetadata(cur)) {
-    // HACK: The AST for an existential metatype of a (parameterized) protocol
-    // still directly wraps the existential type as its instance, which means
-    // we need to reconstitute the enclosing ExistentialType.
-    assert(cur->isExistentialType());
-    if (!cur->is<ExistentialType>()) {
-      cur = ExistentialType::get(cur)->getCanonicalType();
-    }
-    return std::make_pair(cast<ExistentialType>(cur), depth);
-  }
-  return std::nullopt;
-}
-
 llvm::Constant *IRGenModule::getAddrOfStringForMetadataRef(
     StringRef symbolName,
     unsigned alignment,
@@ -526,7 +491,7 @@ CanType IRGenModule::getRuntimeReifiedType(CanType type) {
   }));
 }
 
-CanType IRGenModule::substOpaqueTypesWithUnderlyingTypes(CanType type) {
+Type IRGenModule::substOpaqueTypesWithUnderlyingTypes(Type type) {
   // Substitute away opaque types whose underlying types we're allowed to
   // assume are constant.
   if (type->hasOpaqueArchetype()) {
@@ -537,6 +502,11 @@ CanType IRGenModule::substOpaqueTypesWithUnderlyingTypes(CanType type) {
   return type;
 }
 
+CanType IRGenModule::substOpaqueTypesWithUnderlyingTypes(CanType type) {
+  return substOpaqueTypesWithUnderlyingTypes(static_cast<Type>(type))
+      ->getCanonicalType();
+}
+
 SILType IRGenModule::substOpaqueTypesWithUnderlyingTypes(
     SILType type, CanGenericSignature genericSig) {
   // Substitute away opaque types whose underlying types we're allowed to
@@ -560,7 +530,7 @@ IRGenModule::substOpaqueTypesWithUnderlyingTypes(CanType type,
     auto context = getMaximalTypeExpansionContext();
     return std::make_pair(
        swift::substOpaqueTypesWithUnderlyingTypes(type, context),
-       swift::substOpaqueTypesWithUnderlyingTypes(conformance, type, context));
+       swift::substOpaqueTypesWithUnderlyingTypes(conformance, context));
   }
 
   return std::make_pair(type, conformance);
@@ -780,7 +750,7 @@ static MetadataResponse emitNominalMetadataRef(IRGenFunction &IGF,
             theDecl, genericArgs.Types, NotForDefinition);
 
     response = IGF.emitGenericTypeMetadataAccessFunctionCall(
-        accessor, genericArgs.Values, request);
+        accessor, genericArgs.Values, request, genericArgs.hasPacks);
   }
 
   IGF.setScopedLocalTypeMetadata(theType, response);
@@ -1529,13 +1499,11 @@ emitFunctionTypeMetadataParams(IRGenFunction &IGF,
       flagsArr.addInt32(paramFlags.getIntValue());
     }
   } else {
-    auto parametersPtr =
-        llvm::ConstantPointerNull::get(
-          IGF.IGM.TypeMetadataPtrTy->getPointerTo());
+    auto parametersPtr = llvm::ConstantPointerNull::get(IGF.IGM.PtrTy);
     arguments.push_back(parametersPtr);
   }
 
-  auto *Int32Ptr = IGF.IGM.Int32Ty->getPointerTo();
+  auto *Int32Ptr = IGF.IGM.PtrTy;
   if (flags.hasParameterFlags()) {
     auto *flagsVar = flagsArr.finishAndCreateGlobal(
         "parameter-flags", IGF.IGM.getPointerAlignment(),
@@ -1572,8 +1540,7 @@ emitDynamicFunctionTypeMetadataParams(IRGenFunction &IGF,
 
     arguments.push_back(info.paramFlags.getAddress().getAddress());
   } else {
-    arguments.push_back(llvm::ConstantPointerNull::get(
-        IGF.IGM.Int32Ty->getPointerTo()));
+    arguments.push_back(llvm::ConstantPointerNull::get(IGF.IGM.PtrTy));
   }
 
   return info;
@@ -1993,7 +1960,7 @@ namespace {
 
       // Existential metatypes for extended existentials don't use
       // ExistentialMetatypeMetadata.
-      if (usesExtendedExistentialMetadata(type)) {
+      if (type->getExistentialLayout().needsExtendedShape()) {
         auto metadata = emitExtendedExistentialTypeMetadata(type);
         return setLocal(type, MetadataResponse::forComplete(metadata));
       }
@@ -2359,9 +2326,7 @@ void irgen::emitCacheAccessFunction(IRGenModule &IGM, llvm::Function *accessor,
 
   // For in-place initialization, drill to the first element of the cache.
   case CacheStrategy::SingletonInitialization:
-    cacheVariable =
-      llvm::ConstantExpr::getBitCast(cacheVariable,
-                                     IGM.TypeMetadataPtrTy->getPointerTo());
+    cacheVariable = llvm::ConstantExpr::getBitCast(cacheVariable, IGM.PtrTy);
     break;
 
   case CacheStrategy::Lazy:
@@ -2497,11 +2462,9 @@ void irgen::emitCacheAccessFunction(IRGenModule &IGM, llvm::Function *accessor,
   IGF.Builder.CreateRet(ret);
 }
 
-MetadataResponse
-IRGenFunction::emitGenericTypeMetadataAccessFunctionCall(
-                                              llvm::Function *accessFunction,
-                                              ArrayRef<llvm::Value *> args,
-                                              DynamicMetadataRequest request) {
+MetadataResponse IRGenFunction::emitGenericTypeMetadataAccessFunctionCall(
+    llvm::Function *accessFunction, ArrayRef<llvm::Value *> args,
+    DynamicMetadataRequest request, bool hasPacks) {
 
   SmallVector<llvm::Value *, 8> callArgs;
 
@@ -2525,7 +2488,7 @@ IRGenFunction::emitGenericTypeMetadataAccessFunctionCall(
                                  accessFunction, callArgs);
   call->setDoesNotThrow();
   call->setCallingConv(IGM.SwiftCC);
-  call->setMemoryEffects(allocatedArgsBuffer
+  call->setMemoryEffects(hasPacks || allocatedArgsBuffer
                              ? llvm::MemoryEffects::inaccessibleOrArgMemOnly()
                              : llvm::MemoryEffects::none());
 
@@ -2660,7 +2623,7 @@ MetadataResponse irgen::emitGenericTypeMetadataAccessFunction(
               IGM.Int8PtrTy,                  // arg 1
               IGM.Int8PtrTy,                  // arg 2
               IGM.TypeContextDescriptorPtrTy, // type context descriptor
-              IGM.OnceTy->getPointerTo()      // token pointer
+              IGM.PtrTy                       // token pointer
           },
           generateThunkFn,
           /*noinline*/ true));
@@ -3105,8 +3068,8 @@ static bool shouldAccessByMangledName(IRGenModule &IGM, CanType type) {
     void visitExistentialMetatypeType(CanExistentialMetatypeType meta) {
       // Extended existential metatypes just emit a different shape
       // and don't do any wrapping.
-      if (auto typeAndDepth = usesExtendedExistentialMetadata(meta)) {
-        return visit(typeAndDepth.first);
+      if (meta->getExistentialLayout().needsExtendedShape()) {
+        // return visit(unwrapExistentialMetatype(meta));
       }
 
       // The number of accesses turns out the same as the instance type,
@@ -3229,8 +3192,7 @@ emitMetadataAccessByMangledName(IRGenFunction &IGF, CanType type,
     // Therefore, we can perform a completely naked load here.
     // FIXME: Technically should be "consume", but that introduces barriers
     // in the current LLVM ARM backend.
-    auto cacheWordAddr = subIGF.Builder.CreateBitCast(cache,
-                                                 IGM.Int64Ty->getPointerTo());
+    auto cacheWordAddr = subIGF.Builder.CreateBitCast(cache, IGM.PtrTy);
     auto load = subIGF.Builder.CreateLoad(
         Address(cacheWordAddr, IGM.Int64Ty, Alignment(8)));
     // Make this barrier explicit when building for TSan to avoid false positives.
@@ -3628,8 +3590,8 @@ IRGenFunction::emitTypeMetadataRefForLayout(SILType ty,
 
 llvm::Value *IRGenFunction::emitValueGenericRef(CanType type) {
   if (auto integer = type->getAs<IntegerType>()) {
-    return llvm::ConstantInt::get(IGM.SizeTy,
-                    integer->getValue().zextOrTrunc(IGM.SizeTy->getBitWidth()));
+    auto value = integer->getValue().sextOrTrunc(IGM.SizeTy->getBitWidth());
+    return llvm::ConstantInt::get(IGM.SizeTy, value);
   }
 
   return tryGetLocalTypeData(type, LocalTypeDataKind::forValue());
@@ -3651,8 +3613,8 @@ namespace {
   ///   valid recursive types bottom out in fixed-sized types like classes
   ///   or pointers.)
   class EmitTypeLayoutRef
-    : public CanTypeVisitor<EmitTypeLayoutRef, llvm::Value *,
-                            DynamicMetadataRequest> {
+    : public CanTypeVisitor_AnyNominal<EmitTypeLayoutRef, llvm::Value *,
+                                       DynamicMetadataRequest> {
   private:
     IRGenFunction &IGF;
   public:
@@ -3791,10 +3753,9 @@ namespace {
       llvm_unreachable("Not a valid MetatypeRepresentation.");
     }
 
-    llvm::Value *visitAnyClassType(ClassDecl *classDecl,
+    llvm::Value *visitAnyClassType(CanType type, ClassDecl *classDecl,
                                    DynamicMetadataRequest request) {
       // All class types have the same layout.
-      auto type = classDecl->getDeclaredType()->getCanonicalType();
       switch (type->getReferenceCounting()) {
       case ReferenceCounting::Native:
         return emitFromValueWitnessTable(IGF.IGM.Context.TheNativeObjectType);
@@ -3815,16 +3776,6 @@ namespace {
       llvm_unreachable("Not a valid ReferenceCounting.");
     }
 
-    llvm::Value *visitClassType(CanClassType type,
-                                DynamicMetadataRequest request) {
-      return visitAnyClassType(type->getClassOrBoundGenericClass(), request);
-    }
-
-    llvm::Value *visitBoundGenericClassType(CanBoundGenericClassType type,
-                                            DynamicMetadataRequest request) {
-      return visitAnyClassType(type->getClassOrBoundGenericClass(), request);
-    }
-
     llvm::Value *visitPackType(CanPackType type,
                                DynamicMetadataRequest request) {
       llvm_unreachable("");
@@ -3918,8 +3869,7 @@ namespace {
         }
 
         // Ignore the offsets.
-        auto offsetsPtr =
-          llvm::ConstantPointerNull::get(IGF.IGM.Int32Ty->getPointerTo());
+        auto offsetsPtr = llvm::ConstantPointerNull::get(IGF.IGM.PtrTy);
 
         // Flags.
         auto flags = TupleTypeFlags().withNumElements(type->getNumElements());
diff --git a/lib/IRGen/NonFixedTypeInfo.h b/lib/IRGen/NonFixedTypeInfo.h
index 3bc8f0ed8cbc5..50a00e5ccdf07 100644
--- a/lib/IRGen/NonFixedTypeInfo.h
+++ b/lib/IRGen/NonFixedTypeInfo.h
@@ -54,8 +54,7 @@ class WitnessSizedTypeInfo : public IndirectTypeInfo<Impl, TypeInfo> {
   /// Bit-cast the given pointer to the right type and assume it as an
   /// address of this type.
   Address getAsBitCastAddress(IRGenFunction &IGF, llvm::Value *addr) const {
-    addr = IGF.Builder.CreateBitCast(addr,
-                                     this->getStorageType()->getPointerTo());
+    addr = IGF.Builder.CreateBitCast(addr, IGF.IGM.PtrTy);
     return this->getAddressForPointer(addr);
   }
 
diff --git a/lib/IRGen/Outlining.cpp b/lib/IRGen/Outlining.cpp
index 658dfab2cfbce..96df2cc45c6c8 100644
--- a/lib/IRGen/Outlining.cpp
+++ b/lib/IRGen/Outlining.cpp
@@ -487,11 +487,10 @@ llvm::Constant *IRGenModule::getOrCreateOutlinedCopyAddrHelperFunction(
                               StringRef funcName,
                               CopyAddrHelperGenerator generator) {
   assert(collector.hasFinished());
-  auto ptrTy = ti.getStorageType()->getPointerTo();
 
   llvm::SmallVector<llvm::Type *, 4> paramTys;
-  paramTys.push_back(ptrTy);
-  paramTys.push_back(ptrTy);
+  paramTys.push_back(PtrTy);
+  paramTys.push_back(PtrTy);
   collector.addPolymorphicParameterTypes(paramTys);
 
   IRLinkage *linkage = nullptr;
@@ -500,17 +499,18 @@ llvm::Constant *IRGenModule::getOrCreateOutlinedCopyAddrHelperFunction(
     llvm::GlobalValue::DefaultVisibility,
     llvm::GlobalValue::DefaultStorageClass,
   };
-  auto &TL =
-    getSILModule().Types.getTypeLowering(T, TypeExpansionContext::minimal());
+
   // Opaque result types might lead to different expansions in different files.
   // The default hidden linkonce_odr might lead to linking an implementation
   // from another file that head a different expansion/different
   // signature/different implementation.
-  if (TL.getRecursiveProperties().isTypeExpansionSensitive()) {
+  if (getTypeProperties(T, TypeExpansionContext::minimal())
+        .isTypeExpansionSensitive()) {
     linkage = &privateLinkage;
   }
 
-  return getOrCreateHelperFunction(funcName, ptrTy, paramTys,
+  return getOrCreateHelperFunction(
+      funcName, PtrTy, paramTys,
       [&](IRGenFunction &IGF) {
         auto params = IGF.collectParameters();
         Address src = ti.getAddressForPointer(params.claimNext());
@@ -528,7 +528,7 @@ llvm::Constant *IRGenModule::getOrCreateOutlinedCopyAddrHelperFunction(
 void TypeInfo::callOutlinedDestroy(IRGenFunction &IGF,
                                    Address addr, SILType T) const {
   // Short-cut destruction of trivial values.
-  if (IGF.IGM.getTypeLowering(T).isTrivial())
+  if (IGF.IGM.getTypeProperties(T).isTrivial())
     return;
 
   if (withWitnessableMetadataCollector(
@@ -572,22 +572,22 @@ llvm::Constant *IRGenModule::getOrCreateOutlinedDestroyFunction(
     llvm::GlobalValue::DefaultVisibility,
     llvm::GlobalValue::DefaultStorageClass,
   };
-  auto &TL =
-    getSILModule().Types.getTypeLowering(T, TypeExpansionContext::minimal());
+
   // Opaque result types might lead to different expansions in different files.
   // The default hidden linkonce_odr might lead to linking an implementation
   // from another file that head a different expansion/different
   // signature/different implementation.
-  if (TL.getRecursiveProperties().isTypeExpansionSensitive()) {
+  if (getTypeProperties(T, TypeExpansionContext::minimal())
+        .isTypeExpansionSensitive()) {
     linkage = &privateLinkage;
   }
 
-  auto ptrTy = ti.getStorageType()->getPointerTo();
   llvm::SmallVector<llvm::Type *, 4> paramTys;
-  paramTys.push_back(ptrTy);
+  paramTys.push_back(PtrTy);
   collector.addPolymorphicParameterTypes(paramTys);
 
-  return getOrCreateHelperFunction(funcName, ptrTy, paramTys,
+  return getOrCreateHelperFunction(
+      funcName, PtrTy, paramTys,
       [&](IRGenFunction &IGF) {
         Explosion params = IGF.collectParameters();
         Address addr = ti.getAddressForPointer(params.claimNext());
diff --git a/lib/IRGen/ProtocolInfo.h b/lib/IRGen/ProtocolInfo.h
index 3be67a0c87dc0..a1c3fa9819bc6 100644
--- a/lib/IRGen/ProtocolInfo.h
+++ b/lib/IRGen/ProtocolInfo.h
@@ -124,9 +124,9 @@ class WitnessTableEntry {
     return MethodEntry.Witness;
   }
 
-  static WitnessTableEntry forAssociatedType(AssociatedType ty) {
+  static WitnessTableEntry forAssociatedType(AssociatedTypeDecl *assocType) {
     WitnessTableEntry entry(WitnessKind::AssociatedTypeKind);
-    entry.AssociatedTypeEntry = {ty.getAssociation()};
+    entry.AssociatedTypeEntry = {assocType};
     return entry;
   }
   
@@ -134,9 +134,8 @@ class WitnessTableEntry {
     return Kind == WitnessKind::AssociatedTypeKind;
   }
 
-  bool matchesAssociatedType(AssociatedType assocType) const {
-    return isAssociatedType() &&
-           AssociatedTypeEntry.Association == assocType.getAssociation();
+  bool matchesAssociatedType(AssociatedTypeDecl *assocType) const {
+    return isAssociatedType() && AssociatedTypeEntry.Association == assocType;
   }
 
   AssociatedTypeDecl *getAssociatedType() const {
@@ -223,14 +222,20 @@ class ProtocolInfo final :
 
   ProtocolInfo(ArrayRef<WitnessTableEntry> table, ProtocolInfoKind kind)
       : NumTableEntries(table.size()), Kind(kind) {
-    std::uninitialized_copy(table.begin(), table.end(),
-                            getTrailingObjects<WitnessTableEntry>());
+    std::uninitialized_copy(table.begin(), table.end(), getTrailingObjects());
   }
 
   static std::unique_ptr<ProtocolInfo> create(ArrayRef<WitnessTableEntry> table,
                                               ProtocolInfoKind kind);
 
 public:
+  void operator delete(void *ptr) {
+    const auto *pThis = static_cast<ProtocolInfo *>(ptr);
+    const size_t count = pThis->NumTableEntries;
+    const size_t size = totalSizeToAlloc<WitnessTableEntry>(count);
+    ::operator delete(ptr, size);
+  }
+
   /// The number of witness slots in a conformance to this protocol;
   /// in other words, the size of the table in words.
   unsigned getNumWitnesses() const {
@@ -243,7 +248,7 @@ class ProtocolInfo final :
   /// The addresses of the entries in this array can be passed to
   /// getBaseWitnessIndex/getNonBaseWitnessIndex, below.
   ArrayRef<WitnessTableEntry> getWitnessEntries() const {
-    return {getTrailingObjects<WitnessTableEntry>(), NumTableEntries};
+    return getTrailingObjects(NumTableEntries);
   }
 
   /// Given the address of a witness entry from this PI for a base protocol
@@ -293,7 +298,7 @@ class ProtocolInfo final :
   /// Return the witness index for the type metadata access function
   /// for the given associated type.
   WitnessIndex getAssociatedTypeIndex(IRGenModule &IGM,
-                                      AssociatedType assocType) const;
+                                      AssociatedTypeDecl *assocType) const;
 
   /// Return the witness index for the protocol witness table access
   /// function for the given associated protocol conformance.
diff --git a/lib/IRGen/ScalarTypeInfo.h b/lib/IRGen/ScalarTypeInfo.h
index 204c86462288b..9d108cae10850 100644
--- a/lib/IRGen/ScalarTypeInfo.h
+++ b/lib/IRGen/ScalarTypeInfo.h
@@ -128,8 +128,7 @@ class SingleScalarTypeInfo : public ScalarTypeInfo<Derived, Base> {
       auto nextByteSizedIntTy =
           llvm::IntegerType::get(IGM.getLLVMContext(), nextByteSize);
       auto newAddr =
-          Address(Builder.CreatePointerCast(addr.getAddress(),
-                                            nextByteSizedIntTy->getPointerTo()),
+          Address(Builder.CreatePointerCast(addr.getAddress(), IGF.IGM.PtrTy),
                   nextByteSizedIntTy, addr.getAlignment());
       auto newValue = Builder.CreateZExt(src.claimNext(), nextByteSizedIntTy);
       Builder.CreateStore(newValue, newAddr);
diff --git a/lib/IRGen/StructLayout.cpp b/lib/IRGen/StructLayout.cpp
index 96759e1be4631..a6a7f854af394 100644
--- a/lib/IRGen/StructLayout.cpp
+++ b/lib/IRGen/StructLayout.cpp
@@ -291,8 +291,7 @@ llvm::Constant *StructLayout::emitAlignMask(IRGenModule &IGM) const {
 Address StructLayout::emitCastTo(IRGenFunction &IGF,
                                  llvm::Value *ptr,
                                  const llvm::Twine &name) const {
-  llvm::Value *addr =
-    IGF.Builder.CreateBitCast(ptr, getType()->getPointerTo(), name);
+  llvm::Value *addr = IGF.Builder.CreateBitCast(ptr, IGF.IGM.PtrTy, name);
   return Address(addr, getType(), getAlignment());
 }
 
@@ -589,6 +588,22 @@ unsigned irgen::getNumFields(const NominalTypeDecl *target) {
   return numFields;
 }
 
+bool irgen::isExportableField(Field field) {
+  if (field.getKind() == Field::Kind::Var) {
+    if (field.getVarDecl()->getClangDecl() &&
+        field.getVarDecl()->getFormalAccess() == AccessLevel::Private)
+      return false;
+    // We should not be able to refer to anonymous types.
+    if (const auto *vd = dyn_cast_or_null<clang::ValueDecl>(
+            field.getVarDecl()->getClangDecl()))
+      if (const auto *rd = vd->getType()->getAsRecordDecl())
+        if (rd->isAnonymousStructOrUnion())
+          return false;
+  }
+  // All other fields are exportable
+  return true;
+}
+
 void irgen::forEachField(IRGenModule &IGM, const NominalTypeDecl *typeDecl,
                          llvm::function_ref<void(Field field)> fn) {
   auto classDecl = dyn_cast<ClassDecl>(typeDecl);
@@ -610,6 +625,17 @@ void irgen::forEachField(IRGenModule &IGM, const NominalTypeDecl *typeDecl,
   }
 }
 
+unsigned irgen::countExportableFields(IRGenModule &IGM,
+                                      const NominalTypeDecl *type) {
+  // Don't count private C++ fields that were imported as private Swift fields
+  unsigned exportableFieldCount = 0;
+  forEachField(IGM, type, [&](Field field) {
+    if (isExportableField(field))
+      ++exportableFieldCount;
+  });
+  return exportableFieldCount;
+}
+
 SILType Field::getType(IRGenModule &IGM, SILType baseType) const {
   switch (getKind()) {
   case Field::Var:
diff --git a/lib/IRGen/StructMetadataVisitor.h b/lib/IRGen/StructMetadataVisitor.h
index 4e2aff2f100ae..6ffca8fe0cd22 100644
--- a/lib/IRGen/StructMetadataVisitor.h
+++ b/lib/IRGen/StructMetadataVisitor.h
@@ -17,6 +17,7 @@
 #ifndef SWIFT_IRGEN_STRUCTMETADATALAYOUT_H
 #define SWIFT_IRGEN_STRUCTMETADATALAYOUT_H
 
+#include "Field.h"
 #include "NominalMetadataVisitor.h"
 #include "swift/AST/IRGenOptions.h"
 
@@ -63,8 +64,10 @@ template <class Impl> class StructMetadataVisitor
 
     // Struct field offsets.
     asImpl().noteStartOfFieldOffsets();
-    for (VarDecl *prop : Target->getStoredProperties())
-      asImpl().addFieldOffset(prop);
+    for (VarDecl *prop : Target->getStoredProperties()) {
+      if (isExportableField(prop))
+        asImpl().addFieldOffset(prop);
+    }
 
     asImpl().noteEndOfFieldOffsets();
 
diff --git a/lib/IRGen/SwiftTargetInfo.cpp b/lib/IRGen/SwiftTargetInfo.cpp
index 7c6eccf75505c..0b69902420655 100644
--- a/lib/IRGen/SwiftTargetInfo.cpp
+++ b/lib/IRGen/SwiftTargetInfo.cpp
@@ -49,7 +49,10 @@ static void configureARM64(IRGenModule &IGM, const llvm::Triple &triple,
   }
   setToMask(target.IsObjCPointerBit, 64, SWIFT_ABI_ARM64_IS_OBJC_BIT);
 
-  if (triple.isOSDarwin()) {
+  // Non-embedded Darwin reserves the low 4GB of address space.
+  if (triple.isOSDarwin() &&
+      !IGM.getSwiftModule()->getASTContext().LangOpts.hasFeature(
+          Feature::Embedded)) {
     target.LeastValidPointerValue =
       SWIFT_ABI_DARWIN_ARM64_LEAST_VALID_POINTER;
   }
@@ -104,7 +107,9 @@ static void configureX86_64(IRGenModule &IGM, const llvm::Triple &triple,
               SWIFT_ABI_X86_64_OBJC_RESERVED_BITS_MASK);
   }
 
-  if (triple.isOSDarwin()) {
+  if (triple.isOSDarwin() &&
+      !IGM.getSwiftModule()->getASTContext().LangOpts.hasFeature(
+          Feature::Embedded)) {
     target.LeastValidPointerValue =
       SWIFT_ABI_DARWIN_X86_64_LEAST_VALID_POINTER;
   }
@@ -263,6 +268,9 @@ SwiftTargetInfo SwiftTargetInfo::get(IRGenModule &IGM) {
     break;
   }
 
+  if (IGM.getOptions().CustomLeastValidPointerValue != 0)
+    target.LeastValidPointerValue = IGM.getOptions().CustomLeastValidPointerValue;
+
   return target;
 }
 
diff --git a/lib/IRGen/TBDGen.cpp b/lib/IRGen/TBDGen.cpp
index 3566a1222f1e7..5512e5062e0a9 100644
--- a/lib/IRGen/TBDGen.cpp
+++ b/lib/IRGen/TBDGen.cpp
@@ -245,6 +245,8 @@ getLinkerPlatformId(OriginallyDefinedInAttr::ActiveVersion Ver,
   switch(Ver.Platform) {
   case swift::PlatformKind::none:
     llvm_unreachable("cannot find platform kind");
+  case swift::PlatformKind::FreeBSD:
+    llvm_unreachable("not used for this platform");
   case swift::PlatformKind::OpenBSD:
     llvm_unreachable("not used for this platform");
   case swift::PlatformKind::Windows:
@@ -708,6 +710,9 @@ class APIGenRecorder final : public APIRecorder {
     apigen::APIAvailability availability;
     auto access = apigen::APIAccess::Public;
     if (decl) {
+      if (!shouldRecordDecl(decl))
+        return;
+
       availability = getAvailability(decl);
       if (isSPI(decl))
         access = apigen::APIAccess::Private;
@@ -733,6 +738,9 @@ class APIGenRecorder final : public APIRecorder {
     auto access = apigen::APIAccess::Public;
     auto decl = method.hasDecl() ? method.getDecl() : nullptr;
     if (decl) {
+      if (!shouldRecordDecl(decl))
+        return;
+
       availability = getAvailability(decl);
       if (decl->getDescriptiveKind() == DescriptiveDeclKind::ClassMethod)
         isInstanceMethod = false;
@@ -752,7 +760,7 @@ class APIGenRecorder final : public APIRecorder {
   }
 
 private:
-  apigen::APILoc getAPILocForDecl(const Decl *decl) {
+  apigen::APILoc getAPILocForDecl(const Decl *decl) const {
     if (!decl)
       return defaultLoc;
 
@@ -768,6 +776,15 @@ class APIGenRecorder final : public APIRecorder {
     return apigen::APILoc(std::string(displayName), line, col);
   }
 
+  bool shouldRecordDecl(const Decl *decl) const {
+    // We cannot reason about API access for Clang declarations from header
+    // files as we don't know the header group. API records for header
+    // declarations should be deferred to Clang tools.
+    if (getAPILocForDecl(decl).getFilename().ends_with_insensitive(".h"))
+      return false;
+    return true;
+  }
+
   /// Follow the naming schema that IRGen uses for Categories (see
   /// ClassDataBuilder).
   using CategoryNameKey = std::pair<const ClassDecl *, const ModuleDecl *>;
@@ -809,6 +826,9 @@ class APIGenRecorder final : public APIRecorder {
   }
 
   apigen::ObjCInterfaceRecord *addOrGetObjCInterface(const ClassDecl *decl) {
+    if (!shouldRecordDecl(decl))
+      return nullptr;
+
     auto entry = classMap.find(decl);
     if (entry != classMap.end())
       return entry->second;
@@ -847,6 +867,9 @@ class APIGenRecorder final : public APIRecorder {
   }
 
   apigen::ObjCCategoryRecord *addOrGetObjCCategory(const ExtensionDecl *decl) {
+    if (!shouldRecordDecl(decl))
+      return nullptr;
+
     auto entry = categoryMap.find(decl);
     if (entry != categoryMap.end())
       return entry->second;
diff --git a/lib/IRGen/TBDGenRequests.cpp b/lib/IRGen/TBDGenRequests.cpp
index 23b709c764297..c40e5e025df01 100644
--- a/lib/IRGen/TBDGenRequests.cpp
+++ b/lib/IRGen/TBDGenRequests.cpp
@@ -45,7 +45,7 @@ FileUnit *TBDGenDescriptor::getSingleFile() const {
 ModuleDecl *TBDGenDescriptor::getParentModule() const {
   if (auto *module = Input.dyn_cast<ModuleDecl *>())
     return module;
-  return Input.get<FileUnit *>()->getParentModule();
+  return cast<FileUnit *>(Input)->getParentModule();
 }
 
 const StringRef TBDGenDescriptor::getDataLayoutString() const {
@@ -74,7 +74,7 @@ void swift::simple_display(llvm::raw_ostream &out,
     simple_display(out, module);
   } else {
     out << "file ";
-    simple_display(out, desc.getFileOrModule().get<FileUnit *>());
+    simple_display(out, cast<FileUnit *>(desc.getFileOrModule()));
   }
 }
 
diff --git a/lib/IRGen/TBDGenVisitor.h b/lib/IRGen/TBDGenVisitor.h
index 7da69cea7d47f..d03f3e1de03c8 100644
--- a/lib/IRGen/TBDGenVisitor.h
+++ b/lib/IRGen/TBDGenVisitor.h
@@ -124,7 +124,7 @@ class TBDGenVisitor : public IRSymbolVisitor {
                 APIRecorder &recorder)
       : DataLayoutDescription(dataLayoutString),
         UniversalLinkInfo(target, opts.HasMultipleIGMs, /*forcePublic*/ false,
-                          /*static=*/false, /*mergeableSymbols*/false),
+                          /*static=*/false),
         SwiftModule(swiftModule), Opts(opts), recorder(recorder),
         previousInstallNameMap(parsePreviousModuleInstallNameMap()) {}
 
diff --git a/lib/IRGen/TypeLayout.cpp b/lib/IRGen/TypeLayout.cpp
index 60c879bb38431..61de9e4fb9251 100644
--- a/lib/IRGen/TypeLayout.cpp
+++ b/lib/IRGen/TypeLayout.cpp
@@ -472,7 +472,8 @@ llvm::Function *createMetatypeAccessorFunction(IRGenModule &IGM, SILType ty,
   std::string symbolName =
       mangler.mangleSymbolNameForMangledMetadataAccessorString(
           "get_type_metadata_for_layout_string", sig,
-          fieldType->mapTypeOutOfContext()->getCanonicalType());
+          fieldType->mapTypeOutOfContext()->getCanonicalType(),
+          MangledTypeRefRole::Metadata);
 
   auto helperFn = IGM.getOrCreateHelperFunction(
       symbolName, IGM.TypeMetadataPtrTy /*retTy*/,
@@ -514,8 +515,7 @@ llvm::Function *createFixedEnumLoadTag(IRGenModule &IGM,
       [&](IRGenFunction &IGF) {
         auto enumPtr = IGF.collectParameters().claimNext();
         auto *typeInfo = *entry.fixedTypeInfo;
-        auto enumType = typeInfo->getStorageType()->getPointerTo();
-        auto castEnumPtr = IGF.Builder.CreateBitCast(enumPtr, enumType);
+        auto castEnumPtr = IGF.Builder.CreateBitCast(enumPtr, IGM.PtrTy);
         auto enumAddr = typeInfo->getAddressForPointer(castEnumPtr);
 
         auto &strategy = getEnumImplStrategy(IGM, entry.ty);
@@ -1113,8 +1113,7 @@ static llvm::Value *projectOutlineBuffer(IRGenFunction &IGF, Address buffer,
                                          llvm::Value *alignmentMask) {
   auto &IGM = IGF.IGM;
   auto &Builder = IGF.Builder;
-  Address boxAddress(Builder.CreateBitCast(buffer.getAddress(),
-                                           IGM.RefCountedPtrTy->getPointerTo()),
+  Address boxAddress(Builder.CreateBitCast(buffer.getAddress(), IGM.PtrTy),
                      IGM.RefCountedPtrTy, buffer.getAlignment());
   auto *boxStart = Builder.CreateLoad(boxAddress);
   auto *heapHeaderSize =
@@ -1122,8 +1121,7 @@ static llvm::Value *projectOutlineBuffer(IRGenFunction &IGF, Address buffer,
   auto *startOffset =
       Builder.CreateAnd(Builder.CreateAdd(heapHeaderSize, alignmentMask),
                         Builder.CreateNot(alignmentMask));
-  auto *addressInBox =
-      IGF.emitByteOffsetGEP(boxStart, startOffset, IGM.OpaqueTy);
+  auto *addressInBox = IGF.emitByteOffsetGEP(boxStart, startOffset);
 
   addressInBox = Builder.CreateBitCast(addressInBox, IGM.OpaquePtrTy);
   return addressInBox;
@@ -1168,10 +1166,9 @@ llvm::Value *TypeLayoutEntry::initBufferWithCopyOfBuffer(IRGenFunction &IGF,
   Builder.emitBlock(allocateBB);
   {
     // The buffer stores a reference to a copy-on-write managed heap buffer.
-    auto *destReferenceAddr = Builder.CreateBitCast(
-        dest.getAddress(), IGM.RefCountedPtrTy->getPointerTo());
-    auto *srcReferenceAddr = Builder.CreateBitCast(
-        src.getAddress(), IGM.RefCountedPtrTy->getPointerTo());
+    auto *destReferenceAddr =
+        Builder.CreateBitCast(dest.getAddress(), IGM.PtrTy);
+    auto *srcReferenceAddr = Builder.CreateBitCast(src.getAddress(), IGM.PtrTy);
     auto *srcReference = Builder.CreateLoad(
         Address(srcReferenceAddr, IGM.RefCountedPtrTy, src.getAlignment()));
     IGF.emitNativeStrongRetain(srcReference, IGF.getDefaultAtomicity());
@@ -1326,6 +1323,8 @@ bool ScalarTypeLayoutEntry::refCountString(IRGenModule &IGM,
 }
 
 void ScalarTypeLayoutEntry::destroy(IRGenFunction &IGF, Address addr) const {
+  auto &IGM = IGF.IGM;
+
   switch (scalarKind) {
   case ScalarKind::TriviallyDestroyable:
     return;
@@ -1334,8 +1333,7 @@ void ScalarTypeLayoutEntry::destroy(IRGenFunction &IGF, Address addr) const {
   case ScalarKind::NativeStrongReference: {
     auto alignment = typeInfo.getFixedAlignment();
     auto addressType = typeInfo.getStorageType();
-    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(),
-                                               addressType->getPointerTo());
+    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(), IGM.PtrTy);
     addr = Address(castAddr, addressType, alignment);
     llvm::Value *val = IGF.Builder.CreateLoad(addr, "toDestroy");
     IGF.emitNativeStrongRelease(val, IGF.getDefaultAtomicity());
@@ -1344,8 +1342,7 @@ void ScalarTypeLayoutEntry::destroy(IRGenFunction &IGF, Address addr) const {
   case ScalarKind::ErrorReference: {
     auto alignment = typeInfo.getFixedAlignment();
     auto addressType = typeInfo.getStorageType();
-    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(),
-                                               addressType->getPointerTo());
+    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(), IGM.PtrTy);
     addr = Address(castAddr, addressType, alignment);
     llvm::Value *val = IGF.Builder.CreateLoad(addr, "toDestroy");
     IGF.emitErrorStrongRelease(val);
@@ -1366,8 +1363,7 @@ void ScalarTypeLayoutEntry::destroy(IRGenFunction &IGF, Address addr) const {
   case ScalarKind::UnknownReference: {
     auto alignment = typeInfo.getFixedAlignment();
     auto addressType = typeInfo.getStorageType();
-    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(),
-                                               addressType->getPointerTo());
+    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(), IGM.PtrTy);
     addr = Address(castAddr, addressType, alignment);
     llvm::Value *val = IGF.Builder.CreateLoad(addr, "toDestroy");
     IGF.emitUnknownStrongRelease(val, IGF.getDefaultAtomicity());
@@ -1383,10 +1379,8 @@ void ScalarTypeLayoutEntry::destroy(IRGenFunction &IGF, Address addr) const {
   }
   case ScalarKind::BridgeReference: {
     auto alignment = typeInfo.getFixedAlignment();
-    auto addressType = typeInfo.getStorageType()->getPointerTo();
-    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(),
-                                               addressType->getPointerTo());
-    addr = Address(castAddr, addressType, alignment);
+    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(), IGM.PtrTy);
+    addr = Address(castAddr, IGM.PtrTy, alignment);
     llvm::Value *val = IGF.Builder.CreateLoad(addr, "toDestroy");
     IGF.emitBridgeStrongRelease(val, IGF.getDefaultAtomicity());
     return;
@@ -1394,8 +1388,8 @@ void ScalarTypeLayoutEntry::destroy(IRGenFunction &IGF, Address addr) const {
   case ScalarKind::ObjCReference: {
     auto alignment = typeInfo.getFixedAlignment();
     auto addressType = typeInfo.getStorageType();
-    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(),
-                                               addressType->getPointerTo());
+    auto *castAddr =
+        IGF.Builder.CreateBitCast(addr.getAddress(), IGF.IGM.PtrTy);
     addr = Address(castAddr, addressType, alignment);
     llvm::Value *val = IGF.Builder.CreateLoad(addr, "toDestroy");
     IGF.emitObjCStrongRelease(val);
@@ -1413,8 +1407,7 @@ void ScalarTypeLayoutEntry::destroy(IRGenFunction &IGF, Address addr) const {
     // function pointer, but we need to release the opaque pointer.
     auto alignment = typeInfo.getFixedAlignment();
     auto addressType = typeInfo.getStorageType();
-    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(),
-                                               addressType->getPointerTo());
+    auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(), IGM.PtrTy);
     addr = Address(castAddr, addressType, alignment);
     auto secondElement = IGF.Builder.CreateStructGEP(
         addr, 1, IGF.IGM.getPointerSize(),
@@ -1437,7 +1430,7 @@ void ScalarTypeLayoutEntry::assignWithCopy(IRGenFunction &IGF, Address dest,
                                            Address src) const {
   auto alignment = typeInfo.getFixedAlignment();
   auto storageTy = typeInfo.getStorageType();
-  auto addressType = typeInfo.getStorageType()->getPointerTo();
+  auto *addressType = IGF.IGM.PtrTy;
   auto &Builder = IGF.Builder;
   dest = Address(Builder.CreateBitCast(dest.getAddress(), addressType),
                  storageTy, alignment);
@@ -1450,7 +1443,7 @@ void ScalarTypeLayoutEntry::assignWithTake(IRGenFunction &IGF, Address dest,
                                            Address src) const {
   auto alignment = typeInfo.getFixedAlignment();
   auto storageTy = typeInfo.getStorageType();
-  auto addressType = typeInfo.getStorageType()->getPointerTo();
+  auto *addressType = IGF.IGM.PtrTy;
   auto &Builder = IGF.Builder;
   dest = Address(Builder.CreateBitCast(dest.getAddress(), addressType),
                  storageTy, alignment);
@@ -1463,7 +1456,7 @@ void ScalarTypeLayoutEntry::initWithCopy(IRGenFunction &IGF, Address dest,
                                          Address src) const {
   auto alignment = typeInfo.getFixedAlignment();
   auto storageTy = typeInfo.getStorageType();
-  auto addressType = typeInfo.getStorageType()->getPointerTo();
+  auto *addressType = IGF.IGM.PtrTy;
   auto &Builder = IGF.Builder;
   dest = Address(Builder.CreateBitCast(dest.getAddress(), addressType),
                  storageTy, alignment);
@@ -1475,7 +1468,7 @@ void ScalarTypeLayoutEntry::initWithCopy(IRGenFunction &IGF, Address dest,
 void ScalarTypeLayoutEntry::initWithTake(IRGenFunction &IGF, Address dest,
                                          Address src) const {
   auto alignment = typeInfo.getFixedAlignment();
-  auto addressType = typeInfo.getStorageType()->getPointerTo();
+  auto *addressType = IGF.IGM.PtrTy;
   auto storageTy = typeInfo.getStorageType();
   auto &Builder = IGF.Builder;
   dest = Address(Builder.CreateBitCast(dest.getAddress(), addressType),
@@ -1489,7 +1482,7 @@ void ScalarTypeLayoutEntry::initWithTake(IRGenFunction &IGF, Address dest,
 llvm::Value *ScalarTypeLayoutEntry::getEnumTagSinglePayload(
     IRGenFunction &IGF, llvm::Value *numEmptyCases, Address value) const {
   auto alignment = typeInfo.getFixedAlignment();
-  auto addressType = typeInfo.getStorageType()->getPointerTo();
+  auto *addressType = IGF.IGM.PtrTy;
   auto storageTy = typeInfo.getStorageType();
   auto &Builder = IGF.Builder;
   value = Address(Builder.CreateBitCast(value.getAddress(), addressType),
@@ -1505,7 +1498,7 @@ void ScalarTypeLayoutEntry::storeEnumTagSinglePayload(IRGenFunction &IGF,
                                                 Address addr) const {
   auto alignment = typeInfo.getFixedAlignment();
   auto storageTy = typeInfo.getStorageType();
-  auto addressType = typeInfo.getStorageType()->getPointerTo();
+  auto *addressType = IGF.IGM.PtrTy;
   auto &Builder = IGF.Builder;
   addr = Address(Builder.CreateBitCast(addr.getAddress(), addressType),
                  storageTy, alignment);
@@ -1746,7 +1739,8 @@ AlignedGroupEntry::layoutString(IRGenModule &IGM,
   std::string symbolName =
       mangler.mangleSymbolNameForMangledMetadataAccessorString(
           "type_layout_string", genericSig.getCanonicalSignature(),
-          ty.getASTType()->mapTypeOutOfContext()->getCanonicalType());
+          ty.getASTType()->mapTypeOutOfContext()->getCanonicalType(),
+          MangledTypeRefRole::Metadata);
 
   auto *global = SB.finishAndCreateGlobal(symbolName, IGM.getPointerAlignment(),
                                           /*constant*/ true);
@@ -1819,8 +1813,7 @@ void AlignedGroupEntry::destroy(IRGenFunction &IGF, Address addr) const {
       offset = Size(aligned);
       auto projected = IGF.emitByteOffsetGEP(
           addr.getAddress(),
-          llvm::ConstantInt::get(IGF.IGM.Int32Ty, offset.getValue()),
-          IGF.IGM.OpaquePtrTy);
+          llvm::ConstantInt::get(IGF.IGM.Int32Ty, offset.getValue()));
       entry->destroy(IGF, Address(projected, IGF.IGM.OpaquePtrTy,
                                   *entry->fixedAlignment(IGF.IGM)));
       offset += *entry->fixedSize(IGF.IGM);
@@ -1862,12 +1855,10 @@ void AlignedGroupEntry::withEachEntry(
       offset = Size(aligned);
       auto projectedSrc = IGF.emitByteOffsetGEP(
           src.getAddress(),
-          llvm::ConstantInt::get(IGF.IGM.Int32Ty, offset.getValue()),
-          IGF.IGM.OpaquePtrTy);
+          llvm::ConstantInt::get(IGF.IGM.Int32Ty, offset.getValue()));
       auto projectedDest = IGF.emitByteOffsetGEP(
           dest.getAddress(),
-          llvm::ConstantInt::get(IGF.IGM.Int32Ty, offset.getValue()),
-          IGF.IGM.OpaquePtrTy);
+          llvm::ConstantInt::get(IGF.IGM.Int32Ty, offset.getValue()));
       entryFun(entry,
                Address(projectedDest, IGF.IGM.OpaquePtrTy,
                        *entry->fixedAlignment(IGF.IGM)),
@@ -1955,8 +1946,7 @@ llvm::Value *AlignedGroupEntry::withExtraInhabitantProvidingEntry(
       if (xiCount == maxXICount) {
         auto projected = IGF.emitByteOffsetGEP(
             addr.getAddress(),
-            llvm::ConstantInt::get(IGF.IGM.Int32Ty, offset.getValue()),
-            IGF.IGM.OpaquePtrTy);
+            llvm::ConstantInt::get(IGF.IGM.Int32Ty, offset.getValue()));
         return entryFun(entry,
                         Address(projected, IGF.IGM.OpaquePtrTy,
                                 *entry->fixedAlignment(IGF.IGM)),
@@ -2351,7 +2341,8 @@ EnumTypeLayoutEntry::layoutString(IRGenModule &IGM,
     std::string symbolName =
         mangler.mangleSymbolNameForMangledMetadataAccessorString(
             "type_layout_string", genericSig.getCanonicalSignature(),
-            ty.getASTType()->mapTypeOutOfContext()->getCanonicalType());
+            ty.getASTType()->mapTypeOutOfContext()->getCanonicalType(),
+            MangledTypeRefRole::Metadata);
 
     auto *global = SB.finishAndCreateGlobal(symbolName, IGM.getPointerAlignment(),
                                              /*constant*/ true);
@@ -3747,8 +3738,7 @@ void TypeInfoBasedTypeLayoutEntry::destroy(IRGenFunction &IGF,
                                            Address addr) const {
   auto alignment = typeInfo.getFixedAlignment();
   auto addressType = typeInfo.getStorageType();
-  auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(),
-                                             addressType->getPointerTo());
+  auto *castAddr = IGF.Builder.CreateBitCast(addr.getAddress(), IGF.IGM.PtrTy);
   addr = Address(castAddr, addressType, alignment);
   typeInfo.destroy(IGF, addr, representative, true);
 }
@@ -3759,14 +3749,10 @@ void TypeInfoBasedTypeLayoutEntry::assignWithCopy(IRGenFunction &IGF,
   auto alignment = typeInfo.getFixedAlignment();
   auto addressType = typeInfo.getStorageType();
   auto &Builder = IGF.Builder;
-  dest =
-      Address(Builder.CreateBitCast(dest.getAddress(),
-                                    addressType->getPointerTo()),
-              addressType, alignment);
-  src =
-      Address(Builder.CreateBitCast(src.getAddress(),
-                                    addressType->getPointerTo()),
-              addressType, alignment);
+  dest = Address(Builder.CreateBitCast(dest.getAddress(), IGF.IGM.PtrTy),
+                 addressType, alignment);
+  src = Address(Builder.CreateBitCast(src.getAddress(), IGF.IGM.PtrTy),
+                addressType, alignment);
   typeInfo.assignWithCopy(IGF, dest, src, representative, true);
 }
 
@@ -3776,14 +3762,10 @@ void TypeInfoBasedTypeLayoutEntry::assignWithTake(IRGenFunction &IGF,
   auto alignment = typeInfo.getFixedAlignment();
   auto addressType = typeInfo.getStorageType();
   auto &Builder = IGF.Builder;
-  dest =
-      Address(Builder.CreateBitCast(dest.getAddress(),
-                                    addressType->getPointerTo()),
-              addressType, alignment);
-  src =
-      Address(Builder.CreateBitCast(src.getAddress(),
-                                    addressType->getPointerTo()),
-              addressType, alignment);
+  dest = Address(Builder.CreateBitCast(dest.getAddress(), IGF.IGM.PtrTy),
+                 addressType, alignment);
+  src = Address(Builder.CreateBitCast(src.getAddress(), IGF.IGM.PtrTy),
+                addressType, alignment);
   typeInfo.assignWithTake(IGF, dest, src, representative, true);
 }
 
@@ -3793,14 +3775,10 @@ void TypeInfoBasedTypeLayoutEntry::initWithCopy(IRGenFunction &IGF,
   auto alignment = typeInfo.getFixedAlignment();
   auto addressType = typeInfo.getStorageType();
   auto &Builder = IGF.Builder;
-  dest =
-      Address(Builder.CreateBitCast(dest.getAddress(),
-                                    addressType->getPointerTo()),
-              addressType, alignment);
-  src =
-      Address(Builder.CreateBitCast(src.getAddress(),
-                                    addressType->getPointerTo()),
-              addressType, alignment);
+  dest = Address(Builder.CreateBitCast(dest.getAddress(), IGF.IGM.PtrTy),
+                 addressType, alignment);
+  src = Address(Builder.CreateBitCast(src.getAddress(), IGF.IGM.PtrTy),
+                addressType, alignment);
   typeInfo.initializeWithCopy(IGF, dest, src, representative, true);
 }
 
@@ -3810,14 +3788,10 @@ void TypeInfoBasedTypeLayoutEntry::initWithTake(IRGenFunction &IGF,
   auto alignment = typeInfo.getFixedAlignment();
   auto addressType = typeInfo.getStorageType();
   auto &Builder = IGF.Builder;
-  dest =
-      Address(Builder.CreateBitCast(dest.getAddress(),
-                                    addressType->getPointerTo()),
-              addressType, alignment);
-  src =
-      Address(Builder.CreateBitCast(src.getAddress(),
-                                    addressType->getPointerTo()),
-              addressType, alignment);
+  dest = Address(Builder.CreateBitCast(dest.getAddress(), IGF.IGM.PtrTy),
+                 addressType, alignment);
+  src = Address(Builder.CreateBitCast(src.getAddress(), IGF.IGM.PtrTy),
+                addressType, alignment);
   typeInfo.initializeWithTake(IGF, dest, src, representative, true,
                               /*zeroizeIfSensitive=*/ true);
 }
@@ -3827,8 +3801,7 @@ llvm::Value *TypeInfoBasedTypeLayoutEntry::getEnumTagSinglePayload(
   auto alignment = typeInfo.getFixedAlignment();
   auto addressType = typeInfo.getStorageType();
   auto &Builder = IGF.Builder;
-  value = Address(Builder.CreateBitCast(value.getAddress(),
-                                        addressType->getPointerTo()),
+  value = Address(Builder.CreateBitCast(value.getAddress(), IGF.IGM.PtrTy),
                   addressType, alignment);
   return typeInfo.getEnumTagSinglePayload(IGF, numEmptyCases, value,
                                           representative, true);
@@ -3840,8 +3813,7 @@ void TypeInfoBasedTypeLayoutEntry::storeEnumTagSinglePayload(
   auto alignment = typeInfo.getFixedAlignment();
   auto addressType = typeInfo.getStorageType();
   auto &Builder = IGF.Builder;
-  addr = Address(Builder.CreateBitCast(addr.getAddress(),
-                                       addressType->getPointerTo()),
+  addr = Address(Builder.CreateBitCast(addr.getAddress(), IGF.IGM.PtrTy),
                  addressType, alignment);
   typeInfo.storeEnumTagSinglePayload(IGF, tag, numEmptyCases, addr,
                                      representative, true);
diff --git a/lib/Immediate/SwiftMaterializationUnit.cpp b/lib/Immediate/SwiftMaterializationUnit.cpp
index 7203a8ab141c8..0465188f2b270 100644
--- a/lib/Immediate/SwiftMaterializationUnit.cpp
+++ b/lib/Immediate/SwiftMaterializationUnit.cpp
@@ -197,11 +197,11 @@ renameFunctionBodies(llvm::orc::MaterializationResponsibility &MR,
       if (!Sym->hasName() || !Sym->isCallable())
         continue;
 
-      if (ToRename.count(Sym->getName())) {
-        // FIXME: Get rid of the temporary when Swift's llvm-project is
-        // updated to LLVM 17.
-        auto NewName = G.allocateCString(Twine(mangle(Sym->getName())));
-        Sym->setName({NewName.data(), NewName.size() - 1});
+      const StringRef Name = *Sym->getName();
+
+      if (ToRename.count(Name)) {
+        auto NewName = G.intern(mangle(Name));
+        Sym->setName(NewName);
       }
     }
   }
diff --git a/lib/Index/Index.cpp b/lib/Index/Index.cpp
index 7505ee5057eca..d8a62e3257cfa 100644
--- a/lib/Index/Index.cpp
+++ b/lib/Index/Index.cpp
@@ -33,11 +33,13 @@
 #include "swift/IDE/SourceEntityWalker.h"
 #include "swift/IDE/Utils.h"
 #include "swift/Markup/Markup.h"
+#include "swift/Parse/Lexer.h"
 #include "swift/Sema/IDETypeChecking.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
+#include <optional>
 #include <tuple>
 
 using namespace swift;
@@ -64,7 +66,12 @@ printArtificialName(const swift::AbstractStorageDecl *ASD, AccessorKind AK, llvm
   case AccessorKind::Init:
     OS << "init:" << ASD->getName();
     return false;
-
+  case AccessorKind::Borrow:
+    OS << "borrow:" << ASD->getName();
+    return false;
+  case AccessorKind::Mutate:
+    OS << "mutate:" << ASD->getName();
+    return false;
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
   case AccessorKind::Read:
@@ -123,18 +130,22 @@ class SourceFileOrModule {
   ModuleDecl &getModule() const {
     if (auto SF = SFOrMod.dyn_cast<SourceFile *>())
       return *SF->getParentModule();
-    return *SFOrMod.get<ModuleDecl *>();
+    return *cast<ModuleDecl *>(SFOrMod);
   }
 
   ArrayRef<FileUnit *> getFiles() const {
-    return SFOrMod.is<SourceFile *>() ? *SFOrMod.getAddrOfPtr1()
-                                      : SFOrMod.get<ModuleDecl *>()->getFiles();
+    if (isa<SourceFile *>(SFOrMod)) {
+      SourceFile *const *SF = SFOrMod.getAddrOfPtr1();
+      return ArrayRef((FileUnit *const *)SF, 1);
+    } else {
+      return cast<ModuleDecl *>(SFOrMod)->getFiles();
+    }
   }
 
   StringRef getFilename() const {
     if (auto *SF = SFOrMod.dyn_cast<SourceFile *>())
       return SF->getFilename();
-    return SFOrMod.get<ModuleDecl *>()->getModuleFilename();
+    return cast<ModuleDecl *>(SFOrMod)->getModuleFilename();
   }
 
   void
@@ -145,7 +156,7 @@ class SourceFileOrModule {
     if (auto *SF = SFOrMod.dyn_cast<SourceFile *>()) {
       SF->getImportedModules(Modules, ImportFilter);
     } else {
-      SFOrMod.get<ModuleDecl *>()->getImportedModules(Modules, ImportFilter);
+      cast<ModuleDecl *>(SFOrMod)->getImportedModules(Modules, ImportFilter);
     }
   }
 };
@@ -243,7 +254,7 @@ class ContainerTracker {
         if (auto *D = C.dyn_cast<const Decl *>()) {
           tryContainer(D);
         } else {
-          auto *P = C.get<const Pattern *>();
+          auto *P = cast<const Pattern *>(C);
           P->forEachVariable([&](VarDecl *VD) {
             tryContainer(VD);
           });
@@ -875,10 +886,10 @@ class IndexSwiftASTWalker : public SourceEntityWalker {
     llvm_unreachable("Can't find the generic parameter in the extended type");
   }
 
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type T,
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type T,
                           ReferenceMetaData Data) override {
-    SourceLoc Loc = Range.getStart();
+    SourceLoc Loc = Range.Start;
 
     if (Loc.isInvalid() || isSuppressed(Loc))
       return true;
@@ -918,15 +929,18 @@ class IndexSwiftASTWalker : public SourceEntityWalker {
     // report an occurrence of `foo` in `_foo` and '$foo').
     if (auto *VD = dyn_cast<VarDecl>(D)) {
       if (auto *Wrapped = VD->getOriginalWrappedProperty()) {
-        assert(Range.getByteLength() > 1);
-        if (Range.str().front() == '`') {
-          assert(Range.getByteLength() > 3);
-          assert(Range.str().starts_with("`_") ||
-                 Range.str().starts_with("`$"));
+        CharSourceRange CharRange = Lexer::getCharSourceRangeFromSourceRange(
+            D->getASTContext().SourceMgr, Range);
+        assert(CharRange.getByteLength() > 1);
+        if (CharRange.str().front() == '`') {
+          assert(CharRange.getByteLength() > 3);
+          assert(CharRange.str().starts_with("`_") ||
+                 CharRange.str().starts_with("`$"));
           auto AfterBacktick = Loc.getAdvancedLoc(2);
           reportRef(Wrapped, AfterBacktick, Info, std::nullopt);
         } else {
-          assert(Range.str().front() == '_' || Range.str().front() == '$');
+          assert(CharRange.str().front() == '_' ||
+                 CharRange.str().front() == '$');
           auto AfterDollar = Loc.getAdvancedLoc(1);
           reportRef(Wrapped, AfterDollar, Info, std::nullopt);
         }
@@ -960,7 +974,7 @@ class IndexSwiftASTWalker : public SourceEntityWalker {
     return finishSourceEntity(Info.symInfo, Info.roles);
   }
 
-  bool visitCallAsFunctionReference(ValueDecl *D, CharSourceRange Range,
+  bool visitCallAsFunctionReference(ValueDecl *D, SourceRange Range,
                                     ReferenceMetaData Data) override {
     // Index implicit callAsFunction reference.
     return visitDeclReference(D, Range, /*CtorTyRef*/ nullptr,
@@ -1023,17 +1037,46 @@ class IndexSwiftASTWalker : public SourceEntityWalker {
 
   bool reportRelatedRef(ValueDecl *D, SourceLoc Loc, bool isImplicit, SymbolRoleSet Relations, Decl *Related);
 
-  /// Report references for dependent types
+  /// Report a related type relation for a given TypeRepr.
+  ///
+  /// NOTE: If the dependent type is a typealias, report the underlying types as
+  /// well.
   ///
-  /// NOTE: If the dependent type is a typealias, report the underlying types as well.
+  /// \param TR The type being referenced.
+  /// \param Relations The relationship between the referenced type and the
+  /// passed Decl.
+  /// \param Related The Decl that is referencing the type.
+  /// \param Implicit Whether the reference is implicit, such as for a
+  /// typealias' underlying type.
+  /// \param ParentLoc The parent location of the reference that should be used
+  /// for implicit references.
+  bool reportRelatedTypeRepr(const TypeRepr *TR, SymbolRoleSet Relations,
+                             Decl *Related, bool Implicit, SourceLoc ParentLoc);
+
+  /// Report a related type relation for a Type at a given location.
   ///
   /// \param Ty The type being referenced.
-  /// \param Relations The relationship between the referenced type and the passed Decl.
+  /// \param Relations The relationship between the referenced type and the
+  /// passed Decl.
+  /// \param Related The Decl that is referencing the type.
+  /// \param Implicit Whether the reference is implicit, such as for a
+  /// typealias' underlying type.
+  /// \param Loc The location of the reference.
+  bool reportRelatedType(Type Ty, SymbolRoleSet Relations, Decl *Related,
+                         bool Implicit, SourceLoc Loc);
+
+  /// Report references for dependent types.
+  ///
+  /// NOTE: If the dependent type is a typealias, report the underlying types as
+  /// well.
+  ///
+  /// \param TL The type being referenced.
+  /// \param Relations The relationship between the referenced type and the
+  /// passed Decl.
   /// \param Related The Decl that is referencing the type.
-  /// \param isImplicit Whether the reference is implicit, such as for a typealias' underlying type.
-  /// \param Loc The location of the reference, otherwise the location of the TypeLoc is used.
-  bool reportRelatedTypeRef(const TypeLoc &Ty, SymbolRoleSet Relations, Decl *Related,
-                            bool isImplicit=false, SourceLoc Loc={});
+  bool reportRelatedTypeRef(const TypeLoc &TL, SymbolRoleSet Relations,
+                            Decl *Related);
+
   bool reportInheritedTypeRefs(InheritedTypes Inherited, Decl *Inheritee);
 
   bool reportPseudoGetterDecl(VarDecl *D) {
@@ -1093,10 +1136,12 @@ class IndexSwiftASTWalker : public SourceEntityWalker {
         !SrcMgr.rangeContainsTokenLoc(SrcMgr.getRangeForBuffer(bufferID), loc);
 
     if (inGeneratedBuffer) {
-      std::tie(bufferID, loc) = CurrentModule->getOriginalLocation(loc);
-      if (BufferID.value() != bufferID) {
-        assert(false && "Location is not within file being indexed");
-        return std::nullopt;
+      if (auto unexpandedRange = getUnexpandedMacroRange(SrcMgr, loc)) {
+        loc = unexpandedRange.Start;
+        if (bufferID != SrcMgr.findBufferContainingLoc(loc)) {
+          assert(false && "Location should be within file being indexed");
+          return std::nullopt;
+        }
       }
     }
 
@@ -1470,58 +1515,113 @@ bool IndexSwiftASTWalker::reportRelatedRef(ValueDecl *D, SourceLoc Loc, bool isI
 bool IndexSwiftASTWalker::reportInheritedTypeRefs(InheritedTypes Inherited,
                                                   Decl *Inheritee) {
   for (auto Base : Inherited.getEntries()) {
+    // Suppressed conformances aren't considered base types.
+    if (Base.isSuppressed())
+      continue;
     if (!reportRelatedTypeRef(Base, (SymbolRoleSet) SymbolRole::RelationBaseOf, Inheritee))
       return false;
   }
   return true;
 }
 
-bool IndexSwiftASTWalker::reportRelatedTypeRef(const TypeLoc &Ty, SymbolRoleSet Relations,
-                                               Decl *Related, bool Implicit, SourceLoc Loc) {
-  if (auto *composite = llvm::dyn_cast_or_null<CompositionTypeRepr>(Ty.getTypeRepr())) {
-    SourceLoc IdLoc = Loc.isValid() ? Loc : composite->getSourceLoc();
+bool IndexSwiftASTWalker::reportRelatedTypeRepr(const TypeRepr *TR,
+                                                SymbolRoleSet Relations,
+                                                Decl *Related, bool Implicit,
+                                                SourceLoc ParentLoc) {
+  // Look through parens/specifiers/attributes.
+  while (true) {
+    if (TR->isParenType()) {
+      TR = TR->getWithoutParens();
+      continue;
+    }
+    if (auto *SPR = dyn_cast<SpecifierTypeRepr>(TR)) {
+      TR = SPR->getBase();
+      continue;
+    }
+    if (auto *ATR = dyn_cast<AttributedTypeRepr>(TR)) {
+      TR = ATR->getTypeRepr();
+      continue;
+    }
+    break;
+  }
+  // NOTE: We don't yet handle InverseTypeRepr since we don't have an inverse
+  // relation for inheritance.
+
+  if (auto *composite = dyn_cast<CompositionTypeRepr>(TR)) {
     for (auto *Type : composite->getTypes()) {
-      if (!reportRelatedTypeRef(Type, Relations, Related, /*isImplicit=*/Implicit, IdLoc))
+      if (!reportRelatedTypeRepr(Type, Relations, Related, Implicit,
+                                 ParentLoc)) {
         return false;
+      }
     }
+  }
+  auto *declRefTR = dyn_cast<DeclRefTypeRepr>(TR);
+  if (!declRefTR)
+    return true;
 
+  auto *VD = declRefTR->getBoundDecl();
+  if (!VD)
     return true;
-  } else if (auto *declRefTR = dyn_cast_or_null<DeclRefTypeRepr>(Ty.getTypeRepr())) {
-    SourceLoc IdLoc = Loc.isValid() ? Loc : declRefTR->getLoc();
-    NominalTypeDecl *NTD = nullptr;
-    bool isImplicit = Implicit;
-    if (auto *VD = declRefTR->getBoundDecl()) {
-      if (auto *TAD = dyn_cast<TypeAliasDecl>(VD)) {
-        IndexSymbol Info;
-        if (isImplicit)
-          Info.roles |= (unsigned)SymbolRole::Implicit;
-        if (!reportRef(TAD, IdLoc, Info, std::nullopt))
-          return false;
-        if (auto Ty = TAD->getUnderlyingType()) {
-          NTD = Ty->getAnyNominal();
-          isImplicit = true;
-        }
 
-        if (isa_and_nonnull<CompositionTypeRepr>(TAD->getUnderlyingTypeRepr())) {
-          TypeLoc TL(TAD->getUnderlyingTypeRepr(), TAD->getUnderlyingType());
-          if (!reportRelatedTypeRef(TL, Relations, Related, /*isImplicit=*/true, IdLoc))
-            return false;
-        }
-      } else {
-        NTD = dyn_cast<NominalTypeDecl>(VD);
-      }
+  SourceLoc IdLoc = ParentLoc.isValid() ? ParentLoc : declRefTR->getLoc();
+  if (auto *TAD = dyn_cast<TypeAliasDecl>(VD)) {
+    IndexSymbol Info;
+    if (Implicit)
+      Info.roles |= (unsigned)SymbolRole::Implicit;
+    if (!reportRef(TAD, IdLoc, Info, std::nullopt))
+      return false;
+
+    // Recurse into the underlying type and report any found references as
+    // implicit references at the location of the typealias reference.
+    if (auto *UTR = TAD->getUnderlyingTypeRepr()) {
+      return reportRelatedTypeRepr(UTR, Relations, Related,
+                                   /*Implicit*/ true, /*ParentLoc*/ IdLoc);
     }
-    if (NTD) {
-      if (!reportRelatedRef(NTD, IdLoc, isImplicit, Relations, Related))
+    // If we don't have a TypeRepr available, this is a typealias in another
+    // module, consult the computed underlying type.
+    return reportRelatedType(TAD->getUnderlyingType(), Relations, Related,
+                             /*Implicit*/ true, /*ParentLoc*/ IdLoc);
+  }
+  if (auto *NTD = dyn_cast<NominalTypeDecl>(VD)) {
+    if (!reportRelatedRef(NTD, IdLoc, Implicit, Relations, Related))
+      return false;
+  }
+  return true;
+}
+
+bool IndexSwiftASTWalker::reportRelatedType(Type Ty, SymbolRoleSet Relations,
+                                            Decl *Related, bool Implicit,
+                                            SourceLoc Loc) {
+  // Try decompose a protocol composition.
+  if (auto *PCT = Ty->getAs<ProtocolCompositionType>()) {
+    for (auto member : PCT->getMembers()) {
+      if (!reportRelatedType(member, Relations, Related, Implicit, Loc))
         return false;
     }
     return true;
   }
 
-  if (Ty.getType()) {
-    if (auto nominal = Ty.getType()->getAnyNominal())
-      if (!reportRelatedRef(nominal, Ty.getLoc(), /*isImplicit=*/false, Relations, Related))
-        return false;
+  if (auto *nominal = Ty->getAnyNominal()) {
+    if (!reportRelatedRef(nominal, Loc, Implicit, Relations, Related))
+      return false;
+  }
+  return true;
+}
+
+bool IndexSwiftASTWalker::reportRelatedTypeRef(const TypeLoc &TL,
+                                               SymbolRoleSet Relations,
+                                               Decl *Related) {
+  // If we have a TypeRepr, prefer that since it lets us match up source
+  // locations with the code the user wrote.
+  if (auto *TR = TL.getTypeRepr()) {
+    return reportRelatedTypeRepr(TR, Relations, Related, /*Implicit*/ false,
+                                 /*ParentLoc*/ SourceLoc());
+  }
+  // Otherwise fall back to reporting the Type, this is necessary when indexing
+  // swiftmodules.
+  if (auto Ty = TL.getType()) {
+    return reportRelatedType(Ty, Relations, Related,
+                             /*Implicit*/ false, SourceLoc());
   }
   return true;
 }
diff --git a/lib/Index/IndexRecord.cpp b/lib/Index/IndexRecord.cpp
index 559cfb72546b0..45a8fa6a637c8 100644
--- a/lib/Index/IndexRecord.cpp
+++ b/lib/Index/IndexRecord.cpp
@@ -311,9 +311,9 @@ StringRef StdlibGroupsIndexRecordingConsumer::findGroupForSymbol(const IndexSymb
 }
 
 static bool writeRecord(SymbolTracker &record, std::string Filename,
-                        std::string indexStorePath, DiagnosticEngine *diags,
+                        std::string indexStorePath, bool compress, DiagnosticEngine *diags,
                         std::string &outRecordFile) {
-  IndexRecordWriter recordWriter(indexStorePath);
+  IndexRecordWriter recordWriter(indexStorePath, compress);
   std::string error;
   auto result = recordWriter.beginRecord(
       Filename, record.hashRecord(), error, &outRecordFile);
@@ -360,25 +360,25 @@ static bool writeRecord(SymbolTracker &record, std::string Filename,
 
 static std::unique_ptr<IndexRecordingConsumer>
 makeRecordingConsumer(std::string Filename, std::string indexStorePath,
-                      bool includeLocals, DiagnosticEngine *diags,
+                      bool includeLocals, bool compress, DiagnosticEngine *diags,
                       std::string *outRecordFile,
                       bool *outFailed) {
   return std::make_unique<IndexRecordingConsumer>(includeLocals,
                                                   [=](SymbolTracker &record) {
-    *outFailed = writeRecord(record, Filename, indexStorePath, diags,
+    *outFailed = writeRecord(record, Filename, indexStorePath, compress, diags,
                              *outRecordFile);
   });
 }
 
 static bool
 recordSourceFile(SourceFile *SF, StringRef indexStorePath,
-                 bool includeLocals, DiagnosticEngine &diags,
+                 bool includeLocals, bool compress, DiagnosticEngine &diags,
                  llvm::function_ref<void(StringRef, StringRef)> callback) {
   std::string recordFile;
   bool failed = false;
   auto consumer =
       makeRecordingConsumer(SF->getFilename().str(), indexStorePath.str(),
-                            includeLocals, &diags, &recordFile, &failed);
+                            includeLocals, compress, &diags, &recordFile, &failed);
   indexSourceFile(SF, *consumer);
 
   if (!failed && !recordFile.empty())
@@ -418,6 +418,7 @@ emitDataForSwiftSerializedModule(ModuleDecl *module,
                                  bool indexSystemModules,
                                  bool skipStdlib,
                                  bool includeLocals,
+                                 bool compress,
                                  bool explicitModulebuild,
                                  StringRef targetTriple,
                                  const clang::CompilerInstance &clangCI,
@@ -426,205 +427,13 @@ emitDataForSwiftSerializedModule(ModuleDecl *module,
                                  const PathRemapper &pathRemapper,
                                  SourceFile *initialFile);
 
-static void
-appendSymbolicInterfaceToIndexStorePath(SmallVectorImpl<char> &resultingPath) {
-  llvm::sys::path::append(resultingPath, "interfaces");
-}
-
-static llvm::Error initSymbolicInterfaceStorePath(StringRef storePath) {
-  SmallString<128> subPath = storePath;
-  appendSymbolicInterfaceToIndexStorePath(subPath);
-  std::error_code ec = llvm::sys::fs::create_directories(subPath);
-  if (ec)
-    return llvm::errorCodeToError(ec);
-  return llvm::Error::success();
-}
-
-static void appendSymbolicInterfaceClangModuleFilename(
-    StringRef filePath, SmallVectorImpl<char> &resultingPath) {
-  llvm::sys::path::append(resultingPath, llvm::sys::path::filename(filePath));
-  StringRef extension = ".symbolicswiftinterface";
-  resultingPath.append(extension.begin(), extension.end());
-}
-
-// FIXME (Alex): Share code with IndexUnitWriter in LLVM after refactoring it.
-static llvm::Expected<bool>
-isFileUpToDateForOutputFile(StringRef filePath, StringRef timeCompareFilePath) {
-  auto makeError = [](StringRef path, std::error_code ec) -> llvm::Error {
-    std::string error;
-    llvm::raw_string_ostream(error)
-        << "could not access path '" << path << "': " << ec.message();
-    return llvm::createStringError(ec, error.c_str());
-  };
-  llvm::sys::fs::file_status unitStat;
-  if (std::error_code ec = llvm::sys::fs::status(filePath, unitStat)) {
-    if (ec != std::errc::no_such_file_or_directory && ec != llvm::errc::delete_pending)
-      return makeError(filePath, ec);
-    return false;
-  }
-
-  if (timeCompareFilePath.empty())
-    return true;
-
-  llvm::sys::fs::file_status compareStat;
-  if (std::error_code ec =
-          llvm::sys::fs::status(timeCompareFilePath, compareStat)) {
-    if (ec != std::errc::no_such_file_or_directory && ec != llvm::errc::delete_pending)
-      return makeError(timeCompareFilePath, ec);
-    return true;
-  }
-
-  // Return true (unit is up-to-date) if the file to compare is older than the
-  // unit file.
-  return compareStat.getLastModificationTime() <=
-         unitStat.getLastModificationTime();
-}
-
-/// Emit the symbolic swift interface file for an imported Clang module into the
-/// index store directory.
-///
-/// The swift interface file is emitted only when it doesn't exist yet, or when
-/// the PCM for the Clang module has been updated.
-///
-/// System modules without the 'cplusplus' requirement are not emitted.
-static void emitSymbolicInterfaceForClangModule(
-    ClangModuleUnit *clangModUnit, ModuleDecl *M,
-    const clang::Module *clangModule, StringRef indexStorePath,
-    const clang::CompilerInstance &clangCI, DiagnosticEngine &diags) {
-  if (!M->getASTContext().LangOpts.EnableCXXInterop)
-    return;
-  // Skip system modules without an explicit 'cplusplus' requirement.
-  bool isSystem = clangModUnit->isSystemModule();
-  if (isSystem && !importer::requiresCPlusPlus(clangModule))
-    return;
-
-  // Make sure the `interfaces` directory is created.
-  if (auto err = initSymbolicInterfaceStorePath(indexStorePath)) {
-    llvm::handleAllErrors(std::move(err), [&](const llvm::ECError &ec) {
-      diags.diagnose(SourceLoc(), diag::error_create_symbolic_interfaces_dir,
-                     ec.convertToErrorCode().message());
-    });
-    return;
-  }
-
-  auto moduleRef = clangModule->getASTFile();
-  if (!moduleRef)
-    return;
-
-  // Determine the output name for the symbolic interface file.
-  clang::serialization::ModuleFile *ModFile =
-      clangCI.getASTReader()->getModuleManager().lookup(*moduleRef);
-  assert(ModFile && "no module file loaded for module ?");
-  SmallString<128> interfaceOutputPath = indexStorePath;
-  appendSymbolicInterfaceToIndexStorePath(interfaceOutputPath);
-  appendSymbolicInterfaceClangModuleFilename(ModFile->FileName,
-                                             interfaceOutputPath);
-
-  // Check if the symbolic interface file is already up to date.
-  std::string error;
-  auto upToDate =
-      isFileUpToDateForOutputFile(interfaceOutputPath, ModFile->FileName);
-  if (!upToDate) {
-    llvm::handleAllErrors(
-        upToDate.takeError(), [&](const llvm::StringError &ec) {
-          diags.diagnose(SourceLoc(),
-                         diag::error_symbolic_interfaces_failed_status_check,
-                         ec.getMessage());
-        });
-    return;
-  }
-  if (M->getASTContext().LangOpts.EnableIndexingSystemModuleRemarks) {
-    diags.diagnose(SourceLoc(), diag::remark_emitting_symbolic_interface_module,
-                   interfaceOutputPath, *upToDate);
-  }
-  if (*upToDate)
-    return;
-
-  // Output the interface to a temporary file first.
-  SmallString<128> tempOutputPath = interfaceOutputPath;
-  tempOutputPath += "-%%%%%%%%";
-  int tempFD;
-  if (llvm::sys::fs::createUniqueFile(tempOutputPath.str(), tempFD,
-                                      tempOutputPath)) {
-    llvm::raw_string_ostream errOS(error);
-    errOS << "failed to create temporary file: " << tempOutputPath;
-    diags.diagnose(SourceLoc(), diag::error_write_symbolic_interface,
-                   errOS.str());
-    return;
-  }
-
-  llvm::raw_fd_ostream os(tempFD, /*shouldClose=*/true);
-  StreamPrinter printer(os);
-  ide::printSymbolicSwiftClangModuleInterface(M, printer, clangModule);
-  os.close();
-
-  if (os.has_error()) {
-    llvm::raw_string_ostream errOS(error);
-    errOS << "failed to write '" << tempOutputPath
-          << "': " << os.error().message();
-    diags.diagnose(SourceLoc(), diag::error_write_symbolic_interface,
-                   errOS.str());
-    os.clear_error();
-    llvm::sys::fs::remove(tempOutputPath);
-    return;
-  }
-
-  // Move the resulting output to the destination symbolic interface file.
-  std::error_code ec = llvm::sys::fs::rename(
-      /*from=*/tempOutputPath, /*to=*/interfaceOutputPath);
-  if (ec) {
-    llvm::raw_string_ostream errOS(error);
-    errOS << "failed to rename '" << tempOutputPath << "' to '"
-          << interfaceOutputPath << "': " << ec.message();
-    diags.diagnose(SourceLoc(), diag::error_write_symbolic_interface,
-                   errOS.str());
-    llvm::sys::fs::remove(tempOutputPath);
-    return;
-  }
-}
-
-static void emitTransitiveClangSymbolicInterfacesForSwiftModuleImports(
-    ArrayRef<ImportedModule> imports, StringRef indexStorePath,
-    const clang::CompilerInstance &clangCI, DiagnosticEngine &diags) {
-  auto &fileMgr = clangCI.getFileManager();
-  for (auto &import : imports) {
-    ModuleDecl *mod = import.importedModule;
-    if (mod->isOnoneSupportModule())
-      continue; // ignore the Onone support library.
-    if (mod->isSwiftShimsModule())
-      continue;
-
-    for (auto *FU : mod->getFiles()) {
-      switch (FU->getKind()) {
-      default:
-        break;
-      case FileUnitKind::SerializedAST:
-      case FileUnitKind::DWARFModule:
-      case FileUnitKind::ClangModule: {
-        auto *LFU = cast<LoadedFile>(FU);
-        if (auto F = fileMgr.getFile(LFU->getFilename())) {
-          if (FU->getKind() == FileUnitKind::ClangModule) {
-            auto clangModUnit = cast<ClangModuleUnit>(LFU);
-            if (auto clangMod = clangModUnit->getUnderlyingClangModule()) {
-              // Emit the symbolic interface file in addition to index data.
-              emitSymbolicInterfaceForClangModule(
-                  clangModUnit, mod, clangMod, indexStorePath, clangCI, diags);
-            }
-          }
-          // FIXME: We should keep recursing here into other Swift modules.
-        }
-      }
-      }
-    }
-  }
-}
-
 static void addModuleDependencies(ArrayRef<ImportedModule> imports,
                                   StringRef indexStorePath,
                                   bool indexClangModules,
                                   bool indexSystemModules,
                                   bool skipStdlib,
                                   bool includeLocals,
+                                  bool compress,
                                   bool explicitModuleBuild,
                                   StringRef targetTriple,
                                   const clang::CompilerInstance &clangCI,
@@ -688,11 +497,6 @@ static void addModuleDependencies(ArrayRef<ImportedModule> imports,
             if (shouldIndexModule)
               clang::index::emitIndexDataForModuleFile(clangMod,
                                                        clangCI, unitWriter);
-            // Emit the symbolic interface file in addition to index data.
-            if (indexClangModules)
-              emitSymbolicInterfaceForClangModule(clangModUnit, mod, clangMod,
-                                                  indexStorePath, clangCI,
-                                                  diags);
           }
         } else {
           // Serialized AST file.
@@ -706,6 +510,7 @@ static void addModuleDependencies(ArrayRef<ImportedModule> imports,
                                              indexClangModules,
                                              indexSystemModules, skipStdlib,
                                              includeLocals,
+                                             compress,
                                              explicitModuleBuild,
                                              targetTriple,
                                              clangCI, diags,
@@ -727,9 +532,6 @@ static void addModuleDependencies(ArrayRef<ImportedModule> imports,
             SmallVector<ImportedModule, 4> imports;
             mod->getImportedModules(imports,
                                     ModuleDecl::ImportFilterKind::Exported);
-            if (indexClangModules)
-              emitTransitiveClangSymbolicInterfacesForSwiftModuleImports(
-                  imports, indexStorePath, clangCI, diags);
           }
         }
         clang::index::writer::OpaqueModule opaqMod =
@@ -752,6 +554,7 @@ emitDataForSwiftSerializedModule(ModuleDecl *module,
                                  bool indexSystemModules,
                                  bool skipStdlib,
                                  bool includeLocals,
+                                 bool compress,
                                  bool explicitModuleBuild,
                                  StringRef targetTriple,
                                  const clang::CompilerInstance &clangCI,
@@ -833,7 +636,7 @@ emitDataForSwiftSerializedModule(ModuleDecl *module,
     std::string recordFile;
     bool failed = false;
     auto consumer = makeRecordingConsumer(filename.str(), indexStorePath.str(),
-                                          includeLocals, &diags, &recordFile, &failed);
+                                          includeLocals, compress, &diags, &recordFile, &failed);
     indexModule(module, *consumer);
 
     if (failed)
@@ -877,7 +680,7 @@ emitDataForSwiftSerializedModule(ModuleDecl *module,
       std::string outRecordFile;
       failed =
           failed || writeRecord(tracker, std::string(fileNameWithGroup.str()),
-                                indexStorePath.str(), &diags, outRecordFile);
+                                indexStorePath.str(), compress, &diags, outRecordFile);
       if (failed)
         return false;
       records.emplace_back(outRecordFile, moduleName.str().str());
@@ -899,7 +702,7 @@ emitDataForSwiftSerializedModule(ModuleDecl *module,
   auto clangRemapper = pathRemapper.asClangPathRemapper();
 
   IndexUnitWriter unitWriter(
-      fileMgr, indexStorePath, "swift", swiftVersion, filename, moduleName,
+      fileMgr, indexStorePath, "swift", swiftVersion, compress, filename, moduleName,
       /*MainFile=*/{}, isSystem, /*IsModuleUnit=*/true, isDebugCompilation,
       targetTriple, sysrootPath, clangRemapper, getModuleInfoFromOpaqueModule);
 
@@ -919,7 +722,7 @@ emitDataForSwiftSerializedModule(ModuleDecl *module,
                                        ModuleDecl::ImportFilterKind::Default});
   StringScratchSpace moduleNameScratch;
   addModuleDependencies(imports, indexStorePath, indexClangModules,
-                        indexSystemModules, skipStdlib, includeLocals,
+                        indexSystemModules, skipStdlib, includeLocals, compress,
                         explicitModuleBuild,
                         targetTriple, clangCI, diags, unitWriter,
                         moduleNameScratch, pathRemapper, initialFile);
@@ -936,7 +739,7 @@ static bool
 recordSourceFileUnit(SourceFile *primarySourceFile, StringRef indexUnitToken,
                      StringRef indexStorePath, bool indexClangModules,
                      bool indexSystemModules, bool skipStdlib,
-                     bool includeLocals, bool isDebugCompilation,
+                     bool includeLocals, bool compress, bool isDebugCompilation,
                      bool isExplicitModuleBuild, StringRef targetTriple,
                      ArrayRef<clang::FileEntryRef> fileDependencies,
                      const clang::CompilerInstance &clangCI,
@@ -955,7 +758,7 @@ recordSourceFileUnit(SourceFile *primarySourceFile, StringRef indexUnitToken,
   StringRef swiftVersion;
   StringRef sysrootPath = clangCI.getHeaderSearchOpts().Sysroot;
   IndexUnitWriter unitWriter(
-      fileMgr, indexStorePath, "swift", swiftVersion, indexUnitToken,
+      fileMgr, indexStorePath, "swift", swiftVersion, compress, indexUnitToken,
       module->getNameStr(), *mainFile, isSystem,
       /*isModuleUnit=*/false, isDebugCompilation, targetTriple, sysrootPath,
       clangRemapper, getModuleInfoFromOpaqueModule);
@@ -966,7 +769,7 @@ recordSourceFileUnit(SourceFile *primarySourceFile, StringRef indexUnitToken,
                                         ModuleDecl::getImportFilterLocal());
   StringScratchSpace moduleNameScratch;
   addModuleDependencies(imports, indexStorePath, indexClangModules,
-                        indexSystemModules, skipStdlib, includeLocals,
+                        indexSystemModules, skipStdlib, includeLocals, compress,
                         isExplicitModuleBuild, targetTriple, clangCI, diags,
                         unitWriter, moduleNameScratch, pathRemapper,
                         primarySourceFile);
@@ -975,7 +778,7 @@ recordSourceFileUnit(SourceFile *primarySourceFile, StringRef indexUnitToken,
   for (auto F : fileDependencies)
     unitWriter.addFileDependency(F, /*FIXME:isSystem=*/false, /*Module=*/nullptr);
 
-  recordSourceFile(primarySourceFile, indexStorePath, includeLocals, diags,
+  recordSourceFile(primarySourceFile, indexStorePath, includeLocals, compress, diags,
                    [&](StringRef recordFile, StringRef filename) {
                      if (auto file = fileMgr.getFileRef(filename)) {
                        unitWriter.addRecordFile(
@@ -1024,6 +827,7 @@ bool index::indexAndRecord(SourceFile *primarySourceFile,
                            bool indexSystemModules,
                            bool skipStdlib,
                            bool includeLocals,
+                           bool compress,
                            bool isDebugCompilation,
                            bool isExplicitModuleBuild,
                            StringRef targetTriple,
@@ -1041,7 +845,7 @@ bool index::indexAndRecord(SourceFile *primarySourceFile,
 
   return recordSourceFileUnit(primarySourceFile, indexUnitToken,
                               indexStorePath, indexClangModules,
-                              indexSystemModules, skipStdlib, includeLocals,
+                              indexSystemModules, skipStdlib, includeLocals, compress,
                               isDebugCompilation, isExplicitModuleBuild,
                               targetTriple, {},
                               clangCI, pathRemapper, diags);
@@ -1055,6 +859,7 @@ bool index::indexAndRecord(ModuleDecl *module,
                            bool indexSystemModules,
                            bool skipStdlib,
                            bool includeLocals,
+                           bool compress,
                            bool isDebugCompilation,
                            bool isExplicitModuleBuild,
                            StringRef targetTriple,
@@ -1080,7 +885,7 @@ bool index::indexAndRecord(ModuleDecl *module,
       }
       if (recordSourceFileUnit(SF, indexUnitTokens[unitIndex],
                                indexStorePath, indexClangModules,
-                               indexSystemModules, skipStdlib, includeLocals,
+                               indexSystemModules, skipStdlib, includeLocals, compress,
                                isDebugCompilation, isExplicitModuleBuild,
                                targetTriple, {},
                                clangCI, pathRemapper, diags))
diff --git a/lib/Index/IndexSymbol.cpp b/lib/Index/IndexSymbol.cpp
index 5e32952d9a477..bb51128aefb31 100644
--- a/lib/Index/IndexSymbol.cpp
+++ b/lib/Index/IndexSymbol.cpp
@@ -248,6 +248,7 @@ SymbolInfo index::getSymbolInfoForDecl(const Decl *D) {
     case DeclKind::OpaqueType:
     case DeclKind::BuiltinTuple:
     case DeclKind::MacroExpansion:
+    case DeclKind::Using:
       break;
   }
 
@@ -278,6 +279,10 @@ SymbolSubKind index::getSubKindForAccessor(AccessorKind AK) {
   case AccessorKind::Modify:    return SymbolSubKind::SwiftAccessorModify;
   case AccessorKind::Modify2:   return SymbolSubKind::SwiftAccessorModify;
   case AccessorKind::Init:      return SymbolSubKind::SwiftAccessorInit;
+  case AccessorKind::Borrow:
+    return SymbolSubKind::SwiftAccessorBorrow;
+  case AccessorKind::Mutate:
+    return SymbolSubKind::SwiftAccessorMutate;
   }
 
   llvm_unreachable("Unhandled AccessorKind in switch.");
diff --git a/lib/LLVMPasses/ARCEntryPointBuilder.h b/lib/LLVMPasses/ARCEntryPointBuilder.h
index 6811d8c405b0a..8f069e7a3f097 100644
--- a/lib/LLVMPasses/ARCEntryPointBuilder.h
+++ b/lib/LLVMPasses/ARCEntryPointBuilder.h
@@ -66,8 +66,7 @@ class ARCEntryPointBuilder {
   NullablePtr<Constant> BridgeReleaseN;
 
   // The type cache.
-  NullablePtr<Type> ObjectPtrTy;
-  NullablePtr<Type> BridgeObjectPtrTy;
+  llvm::PointerType *PtrTy;
 
   llvm::CallingConv::ID DefaultCC;
 
@@ -91,8 +90,9 @@ class ARCEntryPointBuilder {
 
 public:
   ARCEntryPointBuilder(Function &F)
-      : B(&*F.begin()), Retain(), ObjectPtrTy(),
-        DefaultCC(SWIFT_DEFAULT_LLVM_CC) { }
+      : B(&*F.begin()), Retain(),
+        PtrTy(llvm::PointerType::getUnqual(B.getContext())),
+        DefaultCC(SWIFT_DEFAULT_LLVM_CC) {}
 
   ~ARCEntryPointBuilder() = default;
   ARCEntryPointBuilder(ARCEntryPointBuilder &&) = delete;
@@ -119,7 +119,7 @@ class ARCEntryPointBuilder {
 
   CallInst *createRetain(Value *V, CallInst *OrigI) {
     // Cast just to make sure that we have the right type.
-    V = B.CreatePointerCast(V, getObjectPtrTy());
+    V = B.CreatePointerCast(V, PtrTy);
 
     // Create the call.
     CallInst *CI = CreateCall(getRetain(OrigI), V);
@@ -128,7 +128,7 @@ class ARCEntryPointBuilder {
 
   CallInst *createRelease(Value *V, CallInst *OrigI) {
     // Cast just to make sure that we have the right type.
-    V = B.CreatePointerCast(V, getObjectPtrTy());
+    V = B.CreatePointerCast(V, PtrTy);
 
     // Create the call.
     CallInst *CI = CreateCall(getRelease(OrigI), V);
@@ -138,29 +138,29 @@ class ARCEntryPointBuilder {
   
   CallInst *createCheckUnowned(Value *V, CallInst *OrigI) {
     // Cast just to make sure that we have the right type.
-    V = B.CreatePointerCast(V, getObjectPtrTy());
-    
+    V = B.CreatePointerCast(V, PtrTy);
+
     CallInst *CI = CreateCall(getCheckUnowned(OrigI), V);
     return CI;
   }
 
   CallInst *createRetainN(Value *V, uint32_t n, CallInst *OrigI) {
     // Cast just to make sure that we have the right object type.
-    V = B.CreatePointerCast(V, getObjectPtrTy());
+    V = B.CreatePointerCast(V, PtrTy);
     CallInst *CI = CreateCall(getRetainN(OrigI), {V, getIntConstant(n)});
     return CI;
   }
 
   CallInst *createReleaseN(Value *V, uint32_t n, CallInst *OrigI) {
     // Cast just to make sure we have the right object type.
-    V = B.CreatePointerCast(V, getObjectPtrTy());
+    V = B.CreatePointerCast(V, PtrTy);
     CallInst *CI = CreateCall(getReleaseN(OrigI), {V, getIntConstant(n)});
     return CI;
   }
 
   CallInst *createUnknownObjectRetainN(Value *V, uint32_t n, CallInst *OrigI) {
     // Cast just to make sure that we have the right object type.
-    V = B.CreatePointerCast(V, getObjectPtrTy());
+    V = B.CreatePointerCast(V, PtrTy);
     CallInst *CI =
         CreateCall(getUnknownObjectRetainN(OrigI), {V, getIntConstant(n)});
     return CI;
@@ -168,7 +168,7 @@ class ARCEntryPointBuilder {
 
   CallInst *createUnknownObjectReleaseN(Value *V, uint32_t n, CallInst *OrigI) {
     // Cast just to make sure we have the right object type.
-    V = B.CreatePointerCast(V, getObjectPtrTy());
+    V = B.CreatePointerCast(V, PtrTy);
     CallInst *CI =
         CreateCall(getUnknownObjectReleaseN(OrigI), {V, getIntConstant(n)});
     return CI;
@@ -176,14 +176,14 @@ class ARCEntryPointBuilder {
 
   CallInst *createBridgeRetainN(Value *V, uint32_t n, CallInst *OrigI) {
     // Cast just to make sure we have the right object type.
-    V = B.CreatePointerCast(V, getBridgeObjectPtrTy());
+    V = B.CreatePointerCast(V, PtrTy);
     CallInst *CI = CreateCall(getBridgeRetainN(OrigI), {V, getIntConstant(n)});
     return CI;
   }
 
   CallInst *createBridgeReleaseN(Value *V, uint32_t n, CallInst *OrigI) {
     // Cast just to make sure we have the right object type.
-    V = B.CreatePointerCast(V, getBridgeObjectPtrTy());
+    V = B.CreatePointerCast(V, PtrTy);
     CallInst *CI = CreateCall(getBridgeReleaseN(OrigI), {V, getIntConstant(n)});
     return CI;
   }
@@ -217,14 +217,13 @@ class ARCEntryPointBuilder {
   Constant *getRetain(CallInst *OrigI) {
     if (Retain)
       return Retain.get();
-    auto *ObjectPtrTy = getObjectPtrTy();
 
     llvm::Constant *cache = nullptr;
-    Retain = getRuntimeFn(
-        getModule(), cache, "Swift",
-        isNonAtomic(OrigI) ? "swift_nonatomic_retain" : "swift_retain",
-        DefaultCC, RuntimeAvailability::AlwaysAvailable, {ObjectPtrTy},
-        {ObjectPtrTy}, {NoUnwind, FirstParamReturned}, {});
+    Retain = getRuntimeFn(getModule(), cache, "Swift",
+                          isNonAtomic(OrigI) ? "swift_nonatomic_retain"
+                                             : "swift_retain",
+                          DefaultCC, RuntimeAvailability::AlwaysAvailable,
+                          {PtrTy}, {PtrTy}, {NoUnwind, FirstParamReturned}, {});
 
     return Retain.get();
   }
@@ -233,7 +232,7 @@ class ARCEntryPointBuilder {
   Constant *getRelease(CallInst *OrigI) {
     if (Release)
       return Release.get();
-    auto *ObjectPtrTy = getObjectPtrTy();
+
     auto *VoidTy = Type::getVoidTy(getModule().getContext());
 
     llvm::Constant *cache = nullptr;
@@ -241,7 +240,7 @@ class ARCEntryPointBuilder {
                            isNonAtomic(OrigI) ? "swift_nonatomic_release"
                                               : "swift_release",
                            DefaultCC, RuntimeAvailability::AlwaysAvailable,
-                           {VoidTy}, {ObjectPtrTy}, {NoUnwind}, {});
+                           {VoidTy}, {PtrTy}, {NoUnwind}, {});
 
     return Release.get();
   }
@@ -249,14 +248,19 @@ class ARCEntryPointBuilder {
   Constant *getCheckUnowned(CallInst *OrigI) {
     if (CheckUnowned)
       return CheckUnowned.get();
-    
-    auto *ObjectPtrTy = getObjectPtrTy();
+
+    auto *ObjectPtrTy = PtrTy;
     auto &M = getModule();
-    auto AttrList = AttributeList::get(M.getContext(), 1, Attribute::NoCapture);
-    AttrList = AttrList.addFnAttribute(M.getContext(), Attribute::NoUnwind);
+    auto &C = M.getContext();
+
+    AttributeList AttrList;
+    AttrList = AttrList.addFnAttribute(C, Attribute::NoUnwind);
+    AttrList = AttrList.addParamAttribute(
+        C, 0, Attribute::getWithCaptureInfo(C, llvm::CaptureInfo::none()));
+
     CheckUnowned = cast<llvm::Function>(
         M.getOrInsertFunction("swift_checkUnowned", AttrList,
-                              Type::getVoidTy(M.getContext()), ObjectPtrTy)
+                              Type::getVoidTy(C), ObjectPtrTy)
             .getCallee());
     if (llvm::Triple(M.getTargetTriple()).isOSBinFormatCOFF() &&
         !llvm::Triple(M.getTargetTriple()).isOSCygMing())
@@ -269,15 +273,15 @@ class ARCEntryPointBuilder {
   Constant *getRetainN(CallInst *OrigI) {
     if (RetainN)
       return RetainN.get();
-    auto *ObjectPtrTy = getObjectPtrTy();
+
     auto *Int32Ty = Type::getInt32Ty(getModule().getContext());
 
     llvm::Constant *cache = nullptr;
     RetainN = getRuntimeFn(
         getModule(), cache, "Swift",
         isNonAtomic(OrigI) ? "swift_nonatomic_retain_n" : "swift_retain_n",
-        DefaultCC, RuntimeAvailability::AlwaysAvailable, {ObjectPtrTy},
-        {ObjectPtrTy, Int32Ty}, {NoUnwind, FirstParamReturned}, {});
+        DefaultCC, RuntimeAvailability::AlwaysAvailable, {PtrTy},
+        {PtrTy, Int32Ty}, {NoUnwind, FirstParamReturned}, {});
 
     return RetainN.get();
   }
@@ -286,7 +290,7 @@ class ARCEntryPointBuilder {
   Constant *getReleaseN(CallInst *OrigI) {
     if (ReleaseN)
       return ReleaseN.get();
-    auto *ObjectPtrTy = getObjectPtrTy();
+
     auto *Int32Ty = Type::getInt32Ty(getModule().getContext());
     auto *VoidTy = Type::getVoidTy(getModule().getContext());
 
@@ -295,7 +299,7 @@ class ARCEntryPointBuilder {
                             isNonAtomic(OrigI) ? "swift_nonatomic_release_n"
                                                : "swift_release_n",
                             DefaultCC, RuntimeAvailability::AlwaysAvailable,
-                            {VoidTy}, {ObjectPtrTy, Int32Ty}, {NoUnwind}, {});
+                            {VoidTy}, {PtrTy, Int32Ty}, {NoUnwind}, {});
 
     return ReleaseN.get();
   }
@@ -305,7 +309,7 @@ class ARCEntryPointBuilder {
   Constant *getUnknownObjectRetainN(CallInst *OrigI) {
     if (UnknownObjectRetainN)
       return UnknownObjectRetainN.get();
-    auto *ObjectPtrTy = getObjectPtrTy();
+
     auto *Int32Ty = Type::getInt32Ty(getModule().getContext());
 
     llvm::Constant *cache = nullptr;
@@ -313,8 +317,8 @@ class ARCEntryPointBuilder {
         getModule(), cache, "Swift",
         isNonAtomic(OrigI) ? "swift_nonatomic_unknownObjectRetain_n"
                            : "swift_unknownObjectRetain_n",
-        DefaultCC, RuntimeAvailability::AlwaysAvailable, {ObjectPtrTy},
-        {ObjectPtrTy, Int32Ty}, {NoUnwind, FirstParamReturned}, {});
+        DefaultCC, RuntimeAvailability::AlwaysAvailable, {PtrTy},
+        {PtrTy, Int32Ty}, {NoUnwind, FirstParamReturned}, {});
 
     return UnknownObjectRetainN.get();
   }
@@ -323,7 +327,7 @@ class ARCEntryPointBuilder {
   Constant *getUnknownObjectReleaseN(CallInst *OrigI) {
     if (UnknownObjectReleaseN)
       return UnknownObjectReleaseN.get();
-    auto *ObjectPtrTy = getObjectPtrTy();
+
     auto *Int32Ty = Type::getInt32Ty(getModule().getContext());
     auto *VoidTy = Type::getVoidTy(getModule().getContext());
 
@@ -333,7 +337,7 @@ class ARCEntryPointBuilder {
         isNonAtomic(OrigI) ? "swift_nonatomic_unknownObjectRelease_n"
                            : "swift_unknownObjectRelease_n",
         DefaultCC, RuntimeAvailability::AlwaysAvailable, {VoidTy},
-        {ObjectPtrTy, Int32Ty}, {NoUnwind}, {});
+        {PtrTy, Int32Ty}, {NoUnwind}, {});
 
     return UnknownObjectReleaseN.get();
   }
@@ -342,16 +346,16 @@ class ARCEntryPointBuilder {
   Constant *getBridgeRetainN(CallInst *OrigI) {
     if (BridgeRetainN)
       return BridgeRetainN.get();
-    auto *BridgeObjectPtrTy = getBridgeObjectPtrTy();
+
     auto *Int32Ty = Type::getInt32Ty(getModule().getContext());
 
     llvm::Constant *cache = nullptr;
-    BridgeRetainN = getRuntimeFn(
-        getModule(), cache, "Swift",
-        isNonAtomic(OrigI) ? "swift_nonatomic_bridgeObjectRetain_n"
-                           : "swift_bridgeObjectRetain_n",
-        DefaultCC, RuntimeAvailability::AlwaysAvailable, {BridgeObjectPtrTy},
-        {BridgeObjectPtrTy, Int32Ty}, {NoUnwind}, {});
+    BridgeRetainN =
+        getRuntimeFn(getModule(), cache, "Swift",
+                     isNonAtomic(OrigI) ? "swift_nonatomic_bridgeObjectRetain_n"
+                                        : "swift_bridgeObjectRetain_n",
+                     DefaultCC, RuntimeAvailability::AlwaysAvailable, {PtrTy},
+                     {PtrTy, Int32Ty}, {NoUnwind}, {});
     return BridgeRetainN.get();
   }
 
@@ -360,7 +364,6 @@ class ARCEntryPointBuilder {
     if (BridgeReleaseN)
       return BridgeReleaseN.get();
 
-    auto *BridgeObjectPtrTy = getBridgeObjectPtrTy();
     auto *Int32Ty = Type::getInt32Ty(getModule().getContext());
     auto *VoidTy = Type::getVoidTy(getModule().getContext());
 
@@ -370,35 +373,10 @@ class ARCEntryPointBuilder {
         isNonAtomic(OrigI) ? "swift_nonatomic_bridgeObjectRelease_n"
                            : "swift_bridgeObjectRelease_n",
         DefaultCC, RuntimeAvailability::AlwaysAvailable, {VoidTy},
-        {BridgeObjectPtrTy, Int32Ty}, {NoUnwind}, {});
+        {PtrTy, Int32Ty}, {NoUnwind}, {});
     return BridgeReleaseN.get();
   }
 
-  Type *getNamedOpaquePtrTy(StringRef name) {
-    auto &M = getModule();
-    if (auto *ty = llvm::StructType::getTypeByName(M.getContext(), name)) {
-      return ty->getPointerTo();
-    }
-
-    // Otherwise, create an anonymous struct type.
-    auto *ty = llvm::StructType::create(M.getContext(), name);
-    return ty->getPointerTo();
-  }
-
-  Type *getObjectPtrTy() {
-    if (ObjectPtrTy)
-      return ObjectPtrTy.get();
-    ObjectPtrTy = getNamedOpaquePtrTy("swift.refcounted");
-    return ObjectPtrTy.get();
-  }
-
-  Type *getBridgeObjectPtrTy() {
-    if (BridgeObjectPtrTy)
-      return BridgeObjectPtrTy.get();
-    BridgeObjectPtrTy = getNamedOpaquePtrTy("swift.bridge");
-    return BridgeObjectPtrTy.get();
-  }
-
   Constant *getIntConstant(uint32_t constant) {
     auto &M = getModule();
     auto *Int32Ty = Type::getInt32Ty(M.getContext());
diff --git a/lib/LLVMPasses/LLVMARCOpts.cpp b/lib/LLVMPasses/LLVMARCOpts.cpp
index e66650b1bfb1b..16d9d2874ff3c 100644
--- a/lib/LLVMPasses/LLVMARCOpts.cpp
+++ b/lib/LLVMPasses/LLVMARCOpts.cpp
@@ -398,7 +398,7 @@ static bool performLocalReleaseMotion(CallInst &Release, BasicBlock &BB,
   // there) move the release to the top of the block.
   // TODO: This is where we'd plug in some global algorithms someday.
   if (&*BBI != &Release) {
-    Release.moveBefore(&*BBI);
+    Release.moveBefore(BBI);
     return true;
   }
 
@@ -520,7 +520,7 @@ static bool performLocalRetainMotion(CallInst &Retain, BasicBlock &BB,
   // If we were able to move the retain down, move it now.
   // TODO: This is where we'd plug in some global algorithms someday.
   if (MadeProgress) {
-    Retain.moveBefore(&*BBI);
+    Retain.moveBefore(BBI);
     return true;
   }
 
diff --git a/lib/LLVMPasses/LLVMMergeFunctions.cpp b/lib/LLVMPasses/LLVMMergeFunctions.cpp
index 3f53edfa891ad..89a58962a1637 100644
--- a/lib/LLVMPasses/LLVMMergeFunctions.cpp
+++ b/lib/LLVMPasses/LLVMMergeFunctions.cpp
@@ -30,7 +30,6 @@
 
 #include "swift/Basic/Assertions.h"
 #include "swift/LLVMPasses/Passes.h"
-#include "clang/AST/StableHash.h"
 #include "clang/Basic/PointerAuthOptions.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/FoldingSet.h"
@@ -55,6 +54,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/SipHash.h"
 #include "llvm/TargetParser/Triple.h"
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Transforms/Utils/FunctionComparator.h"
@@ -258,7 +258,7 @@ class SwiftMergeFunctions {
     FunctionEntry *First;
 
     /// A very cheap hash, used to early exit if functions do not match.
-    llvm::IRHash Hash;
+    llvm::stable_hash Hash;
 
   public:
     // Note the hash is recalculated potentially multiple times, but it is cheap.
@@ -416,9 +416,10 @@ class SwiftMergeFunctions {
         if (auto *GO = dyn_cast<GlobalObject>(value))
           concatenatedCalleeNames += GO->getName();
       }
-      uint64_t rawHash = clang::getStableStringHash(concatenatedCalleeNames);
+      uint64_t hash =
+          llvm::getPointerAuthStableSipHash(concatenatedCalleeNames);
       IntegerType *discrTy = Type::getInt64Ty(Context);
-      discriminator = ConstantInt::get(discrTy, (rawHash % 0xFFFF) + 1);
+      discriminator = ConstantInt::get(discrTy, hash);
     }
   };
 
@@ -713,7 +714,7 @@ bool SwiftMergeFunctions::runOnModule(Module &M) {
 
   // All functions in the module, ordered by hash. Functions with a unique
   // hash value are easily eliminated.
-  std::vector<std::pair<IRHash, Function *>> HashedFuncs;
+  std::vector<std::pair<stable_hash, Function *>> HashedFuncs;
 
   for (Function &Func : M) {
     if (isEligibleFunction(&Func)) {
@@ -721,10 +722,11 @@ bool SwiftMergeFunctions::runOnModule(Module &M) {
     }
   }
 
-  std::stable_sort(
-      HashedFuncs.begin(), HashedFuncs.end(),
-      [](const std::pair<IRHash, Function *> &a,
-         const std::pair<IRHash, Function *> &b) { return a.first < b.first; });
+  std::stable_sort(HashedFuncs.begin(), HashedFuncs.end(),
+                   [](const std::pair<stable_hash, Function *> &a,
+                      const std::pair<stable_hash, Function *> &b) {
+                     return a.first < b.first;
+                   });
 
   std::vector<FunctionEntry> FuncEntryStorage;
   FuncEntryStorage.reserve(HashedFuncs.size());
@@ -1044,8 +1046,9 @@ void SwiftMergeFunctions::replaceCallWithAddedPtrAuth(CallInst *origCall,
     copiedArgs.push_back(op);
   }
 
-  auto *newCall = CallInst::Create(origCall->getFunctionType(),
-    newCallee, copiedArgs, bundles, origCall->getName(), origCall);
+  auto *newCall =
+      CallInst::Create(origCall->getFunctionType(), newCallee, copiedArgs,
+                       bundles, origCall->getName(), origCall->getIterator());
   newCall->setAttributes(origCall->getAttributes());
   newCall->setTailCallKind(origCall->getTailCallKind());
   newCall->setCallingConv(origCall->getCallingConv());
@@ -1079,7 +1082,6 @@ void SwiftMergeFunctions::mergeWithParams(const FunctionInfos &FInfos,
   Function *NewFunction = Function::Create(funcType,
                                            FirstF->getLinkage(),
                                            FirstF->getName() + "Tm");
-  NewFunction->setIsNewDbgInfoFormat(FirstF->IsNewDbgInfoFormat);
   NewFunction->copyAttributesFrom(FirstF);
   // NOTE: this function is not externally available, do ensure that we reset
   // the DLL storage
@@ -1322,8 +1324,9 @@ bool SwiftMergeFunctions::replaceDirectCallers(Function *Old, Function *New,
 
     auto *FType = FunctionType::get(Old->getFunctionType()->getReturnType(),
                                     OldParamTypes, false);
-    auto *FPtrType = PointerType::get(FType,
-                        cast<PointerType>(New->getType())->getAddressSpace());
+    auto *FPtrType =
+        PointerType::get(module->getContext(),
+                         cast<PointerType>(New->getType())->getAddressSpace());
 
     Value *Callee = ConstantExpr::getBitCast(New, FPtrType);
     CallInst *NewCI = Builder.CreateCall(FType, Callee, NewArgs);
diff --git a/lib/Macros/Package.swift b/lib/Macros/Package.swift
new file mode 100644
index 0000000000000..b673dbdf709c9
--- /dev/null
+++ b/lib/Macros/Package.swift
@@ -0,0 +1,46 @@
+// swift-tools-version: 6.2
+
+// Although this could in theory be used to build macros, it's not actually wired up to CMake.
+// This is here purely to provide LSP IDE features when working on Swift macros.
+
+import PackageDescription
+import CompilerPluginSupport
+
+let package = Package(
+	name: "SwiftifyImport",
+	platforms: [.macOS(.v11), .iOS(.v15), .tvOS(.v15), .watchOS(.v8)],
+	products: [
+		.library(
+			name: "SwiftifyImport",
+			targets: [
+				"SwiftifyImport"
+			]
+		),
+		.library(
+			name: "SwiftifyImportMacro",
+			targets: [
+				"SwiftifyImportMacro"
+			]
+		)
+	],
+	dependencies: [
+		.package(path: "../../../swift-syntax")
+	],
+	targets: [
+		.macro(
+			name: "SwiftifyImportMacro",
+			dependencies: [
+				.product(name: "SwiftCompilerPlugin", package: "swift-syntax"),
+                .product(name: "SwiftDiagnostics", package: "swift-syntax"),
+                .product(name: "SwiftParser", package: "swift-syntax"),
+                .product(name: "SwiftSyntax", package: "swift-syntax"),
+                .product(name: "SwiftSyntaxBuilder", package: "swift-syntax"),
+                .product(name: "SwiftSyntaxMacro", package: "swift-syntax")
+			]
+		),
+		.target(
+			name: "SwiftifyImport",
+			dependencies: ["SwiftifyImportMacro"]
+		)
+	]
+)
diff --git a/lib/Macros/Sources/ObservationMacros/ObservableMacro.swift b/lib/Macros/Sources/ObservationMacros/ObservableMacro.swift
index 5334c45166ddb..585a71c23395d 100644
--- a/lib/Macros/Sources/ObservationMacros/ObservableMacro.swift
+++ b/lib/Macros/Sources/ObservationMacros/ObservableMacro.swift
@@ -109,6 +109,15 @@ public struct ObservableMacro {
       trailingTrivia: .space
     )
   }
+
+  static var trackedAttribute: AttributeSyntax {
+    AttributeSyntax(
+      leadingTrivia: .space,
+      atSign: .atSignToken(),
+      attributeName: IdentifierTypeSyntax(name: .identifier(trackedMacroName)),
+      trailingTrivia: .space
+    )
+  }
 }
 
 struct ObservationDiagnostic: DiagnosticMessage {
@@ -142,8 +151,13 @@ extension DiagnosticsError {
   }
 }
 
+
+struct LocalMacroExpansionContext<Context: MacroExpansionContext> {
+  var context: Context
+}
+
 extension DeclModifierListSyntax {
-  func privatePrefixed(_ prefix: String) -> DeclModifierListSyntax {
+  func privatePrefixed(_ prefix: String, in context: LocalMacroExpansionContext<some MacroExpansionContext>) -> DeclModifierListSyntax {
     let modifier: DeclModifierSyntax = DeclModifierSyntax(name: "private", trailingTrivia: .space)
     return [modifier] + filter {
       switch $0.name.tokenKind {
@@ -170,7 +184,7 @@ extension DeclModifierListSyntax {
 }
 
 extension TokenSyntax {
-  func privatePrefixed(_ prefix: String) -> TokenSyntax {
+  func privatePrefixed(_ prefix: String, in context: LocalMacroExpansionContext<some MacroExpansionContext>) -> TokenSyntax {
     switch tokenKind {
     case .identifier(let identifier):
       return TokenSyntax(.identifier(prefix + identifier), leadingTrivia: leadingTrivia, trailingTrivia: trailingTrivia, presence: presence)
@@ -180,8 +194,58 @@ extension TokenSyntax {
   }
 }
 
+extension CodeBlockSyntax {
+  func locationAnnotated(in context: LocalMacroExpansionContext<some MacroExpansionContext>) -> CodeBlockSyntax {
+    guard let firstStatement = statements.first, let loc = context.context.location(of: firstStatement) else {
+      return self
+    }
+    
+    return CodeBlockSyntax(
+      leadingTrivia: leadingTrivia,
+      leftBrace: leftBrace,
+      statements: CodeBlockItemListSyntax {
+        "#sourceLocation(file: \(loc.file), line: \(loc.line))"
+        statements
+        "#sourceLocation()"
+      },
+      rightBrace: rightBrace,
+      trailingTrivia: trailingTrivia
+    )
+  }
+}
+
+
+extension AccessorDeclSyntax {
+  func locationAnnotated(in context: LocalMacroExpansionContext<some MacroExpansionContext>) -> AccessorDeclSyntax {
+    return AccessorDeclSyntax(
+      leadingTrivia: leadingTrivia,
+      attributes: attributes,
+      modifier: modifier,
+      accessorSpecifier: accessorSpecifier,
+      parameters: parameters,
+      effectSpecifiers: effectSpecifiers,
+      body: body?.locationAnnotated(in: context),
+      trailingTrivia: trailingTrivia
+    )
+  }
+}
+
+extension AccessorBlockSyntax {
+  func locationAnnotated(in context: LocalMacroExpansionContext<some MacroExpansionContext>) -> AccessorBlockSyntax {
+    switch accessors {
+    case .accessors(let accessorList):
+      let remapped = AccessorDeclListSyntax {
+        accessorList.map { $0.locationAnnotated(in: context) }
+      }
+      return AccessorBlockSyntax(accessors: .accessors(remapped))
+    case .getter(let codeBlockList):
+      return AccessorBlockSyntax(accessors: .getter(codeBlockList))
+    }
+  }
+}
+
 extension PatternBindingListSyntax {
-  func privatePrefixed(_ prefix: String) -> PatternBindingListSyntax {
+  func privatePrefixed(_ prefix: String, in context: LocalMacroExpansionContext<some MacroExpansionContext>) -> PatternBindingListSyntax {
     var bindings = self.map { $0 }
     for index in 0..<bindings.count {
       let binding = bindings[index]
@@ -190,12 +254,12 @@ extension PatternBindingListSyntax {
           leadingTrivia: binding.leadingTrivia,
           pattern: IdentifierPatternSyntax(
             leadingTrivia: identifier.leadingTrivia,
-            identifier: identifier.identifier.privatePrefixed(prefix),
+            identifier: identifier.identifier.privatePrefixed(prefix, in: context),
             trailingTrivia: identifier.trailingTrivia
           ),
           typeAnnotation: binding.typeAnnotation,
           initializer: binding.initializer,
-          accessorBlock: binding.accessorBlock,
+          accessorBlock: binding.accessorBlock?.locationAnnotated(in: context),
           trailingComma: binding.trailingComma,
           trailingTrivia: binding.trailingTrivia)
         
@@ -207,14 +271,20 @@ extension PatternBindingListSyntax {
 }
 
 extension VariableDeclSyntax {
-  func privatePrefixed(_ prefix: String, addingAttribute attribute: AttributeSyntax) -> VariableDeclSyntax {
-    let newAttributes = attributes + [.attribute(attribute)]
+  func privatePrefixed(_ prefix: String, addingAttribute attribute: AttributeSyntax, removingAttribute toRemove: AttributeSyntax, in context: LocalMacroExpansionContext<some MacroExpansionContext>) -> VariableDeclSyntax {
+    let newAttributes = attributes.filter { attribute in
+      switch attribute {
+      case .attribute(let attr):
+        attr.attributeName.identifier != toRemove.attributeName.identifier
+      default: true
+      }
+    } + [.attribute(attribute)]
     return VariableDeclSyntax(
       leadingTrivia: leadingTrivia,
       attributes: newAttributes,
-      modifiers: modifiers.privatePrefixed(prefix),
+      modifiers: modifiers.privatePrefixed(prefix, in: context),
       bindingSpecifier: TokenSyntax(bindingSpecifier.tokenKind, leadingTrivia: .space, trailingTrivia: .space, presence: .present),
-      bindings: bindings.privatePrefixed(prefix),
+      bindings: bindings.privatePrefixed(prefix, in: context),
       trailingTrivia: trailingTrivia
     )
   }
@@ -311,7 +381,7 @@ extension ObservableMacro: ExtensionMacro {
     }
 
     let decl: DeclSyntax = """
-        extension \(raw: type.trimmedDescription): \(raw: qualifiedConformanceName) {}
+        extension \(raw: type.trimmedDescription): nonisolated \(raw: qualifiedConformanceName) {}
         """
     let ext = decl.cast(ExtensionDeclSyntax.self)
 
@@ -417,12 +487,12 @@ extension ObservationTrackedMacro: PeerMacro {
       return []
     }
     
-    if property.hasMacroApplication(ObservableMacro.ignoredMacroName) ||
-       property.hasMacroApplication(ObservableMacro.trackedMacroName) {
+    if property.hasMacroApplication(ObservableMacro.ignoredMacroName) {
       return []
     }
     
-    let storage = DeclSyntax(property.privatePrefixed("_", addingAttribute: ObservableMacro.ignoredAttribute))
+    let localContext = LocalMacroExpansionContext(context: context)
+    let storage = DeclSyntax(property.privatePrefixed("_", addingAttribute: ObservableMacro.ignoredAttribute, removingAttribute: ObservableMacro.trackedAttribute, in: localContext))
     return [storage]
   }
 }
diff --git a/lib/Macros/Sources/SwiftMacros/CMakeLists.txt b/lib/Macros/Sources/SwiftMacros/CMakeLists.txt
index cde6d3f4f9491..6c6a9784000d9 100644
--- a/lib/Macros/Sources/SwiftMacros/CMakeLists.txt
+++ b/lib/Macros/Sources/SwiftMacros/CMakeLists.txt
@@ -14,7 +14,6 @@ add_swift_macro_library(SwiftMacros
   OptionSetMacro.swift
   DebugDescriptionMacro.swift
   DistributedResolvableMacro.swift
-  TaskMacro.swift
   SyntaxExtensions.swift
   TaskLocalMacro.swift
   SwiftifyImportMacro.swift
diff --git a/lib/Macros/Sources/SwiftMacros/SwiftifyImportMacro.swift b/lib/Macros/Sources/SwiftMacros/SwiftifyImportMacro.swift
index 8ef08d222b968..32123e1de0aaf 100644
--- a/lib/Macros/Sources/SwiftMacros/SwiftifyImportMacro.swift
+++ b/lib/Macros/Sources/SwiftMacros/SwiftifyImportMacro.swift
@@ -40,23 +40,22 @@ protocol ParamInfo: CustomStringConvertible {
   var dependencies: [LifetimeDependence] { get set }
 
   func getBoundsCheckedThunkBuilder(
-    _ base: BoundsCheckedThunkBuilder, _ funcDecl: FunctionDeclSyntax,
-    _ skipTrivialCount: Bool
+    _ base: BoundsCheckedThunkBuilder, _ funcDecl: FunctionParts
   ) -> BoundsCheckedThunkBuilder
 }
 
-func tryGetParamName(_ funcDecl: FunctionDeclSyntax, _ expr: SwiftifyExpr) -> TokenSyntax? {
+func tryGetParamName(_ funcDecl: FunctionParts, _ expr: SwiftifyExpr) -> TokenSyntax? {
   switch expr {
   case .param(let i):
     let funcParam = getParam(funcDecl, i - 1)
-    return funcParam.secondName ?? funcParam.firstName
+    return funcParam.name
   case .`self`:
     return .keyword(.self)
   default: return nil
   }
 }
 
-func getSwiftifyExprType(_ funcDecl: FunctionDeclSyntax, _ expr: SwiftifyExpr) -> TypeSyntax {
+func getSwiftifyExprType(_ funcDecl: FunctionParts, _ expr: SwiftifyExpr) -> TypeSyntax {
   switch expr {
   case .param(let i):
     let funcParam = getParam(funcDecl, i - 1)
@@ -80,20 +79,19 @@ struct CxxSpan: ParamInfo {
   }
 
   func getBoundsCheckedThunkBuilder(
-    _ base: BoundsCheckedThunkBuilder, _ funcDecl: FunctionDeclSyntax,
-    _ skipTrivialCount: Bool
+    _ base: BoundsCheckedThunkBuilder, _ funcDecl: FunctionParts
   ) -> BoundsCheckedThunkBuilder {
     switch pointerIndex {
     case .param(let i):
       return CxxSpanThunkBuilder(
-        base: base, index: i - 1, signature: funcDecl.signature,
+        base: base, index: i - 1, funcDecl: funcDecl,
         typeMappings: typeMappings, node: original, nonescaping: nonescaping)
     case .return:
       if dependencies.isEmpty {
         return base
       }
       return CxxSpanReturnThunkBuilder(
-        base: base, signature: funcDecl.signature,
+        base: base, funcDecl: funcDecl,
         typeMappings: typeMappings, node: original)
     case .self:
       return base
@@ -117,19 +115,18 @@ struct CountedBy: ParamInfo {
   }
 
   func getBoundsCheckedThunkBuilder(
-    _ base: BoundsCheckedThunkBuilder, _ funcDecl: FunctionDeclSyntax,
-    _ skipTrivialCount: Bool
+    _ base: BoundsCheckedThunkBuilder, _ funcDecl: FunctionParts
   ) -> BoundsCheckedThunkBuilder {
     switch pointerIndex {
     case .param(let i):
       return CountedOrSizedPointerThunkBuilder(
         base: base, index: i - 1, countExpr: count,
-        signature: funcDecl.signature,
-        nonescaping: nonescaping, isSizedBy: sizedBy, skipTrivialCount: skipTrivialCount)
+        funcDecl: funcDecl,
+        nonescaping: nonescaping, isSizedBy: sizedBy)
     case .return:
       return CountedOrSizedReturnPointerThunkBuilder(
         base: base, countExpr: count,
-        signature: funcDecl.signature,
+        funcDecl: funcDecl,
         nonescaping: nonescaping, isSizedBy: sizedBy, dependencies: dependencies)
     case .self:
       return base
@@ -265,12 +262,11 @@ func isRawPointerType(text: String) -> Bool {
 
 // Remove std. or std.__1. prefix
 func getUnqualifiedStdName(_ type: String) -> String? {
-  if type.hasPrefix("std.") {
-    var ty = type.dropFirst(4)
-    if ty.hasPrefix("__1.") {
-      ty = ty.dropFirst(4)
+  let prefixes = ["std.__1.", "std.__ndk1.", "std."]
+  for prefix in prefixes {
+    if type.hasPrefix(prefix) {
+      return String(type.dropFirst(prefix.count))
     }
-    return String(ty)
   }
   return nil
 }
@@ -332,10 +328,7 @@ func transformType(
   let text = name.text
   let isRaw = isRawPointerType(text: text)
   if isRaw && !isSizedBy {
-    throw DiagnosticError("raw pointers only supported for SizedBy", node: name)
-  }
-  if !isRaw && isSizedBy {
-    throw DiagnosticError("SizedBy only supported for raw pointers", node: name)
+    throw DiagnosticError("void pointers not supported for countedBy", node: name)
   }
 
   guard let kind: Mutability = getPointerMutability(text: text) else {
@@ -378,13 +371,47 @@ func isMutablePointerType(_ type: TypeSyntax) -> Bool {
   }
 }
 
+func getPointeeType(_ type: TypeSyntax) -> TypeSyntax? {
+  if let optType = type.as(OptionalTypeSyntax.self) {
+    return getPointeeType(optType.wrappedType)
+  }
+  if let impOptType = type.as(ImplicitlyUnwrappedOptionalTypeSyntax.self) {
+    return getPointeeType(impOptType.wrappedType)
+  }
+  if let attrType = type.as(AttributedTypeSyntax.self) {
+    return getPointeeType(attrType.baseType)
+  }
+
+  guard let idType = type.as(IdentifierTypeSyntax.self) else {
+    return nil
+  }
+  let text = idType.name.text
+  if text != "UnsafePointer" && text != "UnsafeMutablePointer" {
+    return nil
+  }
+  guard let x = idType.genericArgumentClause else {
+    return nil
+  }
+  guard let y = x.arguments.first else {
+    return nil
+  }
+  return y.argument.as(TypeSyntax.self)
+}
+
 protocol BoundsCheckedThunkBuilder {
   func buildFunctionCall(_ pointerArgs: [Int: ExprSyntax]) throws -> ExprSyntax
-  func buildBoundsChecks() throws -> [CodeBlockItemSyntax.Item]
+  // buildBasicBoundsChecks creates a variable with the same name as the parameter it replaced,
+  // or if that variable already exists (because another pointer has the same count), checks that
+  // the values match.
+  func buildBasicBoundsChecks(_ extractedCountArgs: inout Set<Int>) throws -> [CodeBlockItemSyntax.Item]
+  // buildCompoundBoundsChecks performs bounds checks of count expressions that contain operations.
+  // It may refer to names constructed in buildBasicBoundsChecks (in the case of shared variables),
+  // so those must come before this in the function body.
+  func buildCompoundBoundsChecks() throws -> [CodeBlockItemSyntax.Item]
   // The second component of the return value is true when only the return type of the
   // function signature was changed.
   func buildFunctionSignature(_ argTypes: [Int: TypeSyntax?], _ returnType: TypeSyntax?) throws
-    -> (FunctionSignatureSyntax, Bool)
+    -> FunctionSignatureSyntax
 }
 
 func getParam(_ signature: FunctionSignatureSyntax, _ paramIndex: Int) -> FunctionParameterSyntax {
@@ -396,23 +423,26 @@ func getParam(_ signature: FunctionSignatureSyntax, _ paramIndex: Int) -> Functi
   }
 }
 
-func getParam(_ funcDecl: FunctionDeclSyntax, _ paramIndex: Int) -> FunctionParameterSyntax {
+func getParam(_ funcDecl: FunctionParts, _ paramIndex: Int) -> FunctionParameterSyntax {
   return getParam(funcDecl.signature, paramIndex)
 }
 
 struct FunctionCallBuilder: BoundsCheckedThunkBuilder {
-  let base: FunctionDeclSyntax
+  let base: FunctionParts
 
-  init(_ function: FunctionDeclSyntax) {
+  init(_ function: FunctionParts) {
     base = function
   }
 
-  func buildBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
+  func buildBasicBoundsChecks(_ extractedCountArgs: inout Set<Int>) throws -> [CodeBlockItemSyntax.Item] {
+    return []
+  }
+  func buildCompoundBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
     return []
   }
 
   func buildFunctionSignature(_ argTypes: [Int: TypeSyntax?], _ returnType: TypeSyntax?) throws
-    -> (FunctionSignatureSyntax, Bool)
+    -> FunctionSignatureSyntax
   {
     var newParams = base.signature.parameterClause.parameters.enumerated().filter {
       let type = argTypes[$0.offset]
@@ -430,16 +460,21 @@ struct FunctionCallBuilder: BoundsCheckedThunkBuilder {
     if returnType != nil {
       sig = sig.with(\.returnClause!.type, returnType!)
     }
-    return (sig, (argTypes.count == 0 && returnType != nil))
+    return sig
   }
 
   func buildFunctionCall(_ pointerArgs: [Int: ExprSyntax]) throws -> ExprSyntax {
     let functionRef = DeclReferenceExprSyntax(baseName: base.name)
     let args: [ExprSyntax] = base.signature.parameterClause.parameters.enumerated()
       .map { (i: Int, param: FunctionParameterSyntax) in
-        let name = param.secondName ?? param.firstName
-        let declref = DeclReferenceExprSyntax(baseName: name)
-        return pointerArgs[i] ?? ExprSyntax(declref)
+        if let overrideArg = pointerArgs[i] {
+          return overrideArg
+        }
+        if isInout(getParam(base.signature, i).type) {
+          return ExprSyntax("&\(param.name)")
+        } else {
+          return ExprSyntax("\(param.name)")
+        }
       }
     let labels: [TokenSyntax?] = base.signature.parameterClause.parameters.map { param in
       let firstName = param.firstName.trimmed
@@ -455,32 +490,40 @@ struct FunctionCallBuilder: BoundsCheckedThunkBuilder {
         comma = .commaToken()
       }
       let colon: TokenSyntax? = label != nil ? .colonToken() : nil
-      return LabeledExprSyntax(label: label, colon: colon, expression: arg, trailingComma: comma)
+      // The compiler emits warnings if you unnecessarily escape labels in function calls
+      return LabeledExprSyntax(label: label?.withoutBackticks, colon: colon, expression: arg, trailingComma: comma)
     }
     let call = ExprSyntax(
       FunctionCallExprSyntax(
         calledExpression: functionRef, leftParen: .leftParenToken(),
         arguments: LabeledExprListSyntax(labeledArgs), rightParen: .rightParenToken()))
-    return "unsafe \(call)"
+    if base.name.tokenKind == .keyword(.`init`) {
+      return "unsafe self.\(call)"
+    } else {
+      return "unsafe \(call)"
+    }
   }
 }
 
 struct CxxSpanThunkBuilder: SpanBoundsThunkBuilder, ParamBoundsThunkBuilder {
   public let base: BoundsCheckedThunkBuilder
   public let index: Int
-  public let signature: FunctionSignatureSyntax
+  public let funcDecl: FunctionParts
   public let typeMappings: [String: String]
   public let node: SyntaxProtocol
   public let nonescaping: Bool
   let isSizedBy: Bool = false
   let isParameter: Bool = true
 
-  func buildBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
-    return try base.buildBoundsChecks()
+  func buildBasicBoundsChecks(_ extractedCountArgs: inout Set<Int>) throws -> [CodeBlockItemSyntax.Item] {
+    return try base.buildBasicBoundsChecks(&extractedCountArgs)
+  }
+  func buildCompoundBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
+    return try base.buildCompoundBoundsChecks()
   }
 
   func buildFunctionSignature(_ argTypes: [Int: TypeSyntax?], _ returnType: TypeSyntax?) throws
-    -> (FunctionSignatureSyntax, Bool)
+    -> FunctionSignatureSyntax
   {
     var types = argTypes
     types[index] = try newType
@@ -497,7 +540,7 @@ struct CxxSpanThunkBuilder: SpanBoundsThunkBuilder, ParamBoundsThunkBuilder {
       args[index] = ExprSyntax("\(raw: typeName)(\(raw: name))")
       return try base.buildFunctionCall(args)
     } else {
-      let unwrappedName = TokenSyntax("_\(name)Ptr")
+      let unwrappedName = TokenSyntax("_\(name.withoutBackticks)Ptr")
       args[index] = ExprSyntax("\(raw: typeName)(\(unwrappedName))")
       let call = try base.buildFunctionCall(args)
 
@@ -505,9 +548,9 @@ struct CxxSpanThunkBuilder: SpanBoundsThunkBuilder, ParamBoundsThunkBuilder {
       // so unwrap it to an UnsafeMutableBufferPointer that we can cast
       let unwrappedCall = ExprSyntax(
         """
-          unsafe \(name).withUnsafeMutableBufferPointer { \(unwrappedName) in
-            return \(call)
-          }
+        unsafe \(name).withUnsafeMutableBufferPointer { \(unwrappedName) in
+          return \(call)
+        }
         """)
       return unwrappedCall
     }
@@ -516,7 +559,7 @@ struct CxxSpanThunkBuilder: SpanBoundsThunkBuilder, ParamBoundsThunkBuilder {
 
 struct CxxSpanReturnThunkBuilder: SpanBoundsThunkBuilder {
   public let base: BoundsCheckedThunkBuilder
-  public let signature: FunctionSignatureSyntax
+  public let funcDecl: FunctionParts
   public let typeMappings: [String: String]
   public let node: SyntaxProtocol
   let isParameter: Bool = false
@@ -525,12 +568,15 @@ struct CxxSpanReturnThunkBuilder: SpanBoundsThunkBuilder {
     return signature.returnClause!.type
   }
 
-  func buildBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
-    return try base.buildBoundsChecks()
+  func buildBasicBoundsChecks(_ extractedCountArgs: inout Set<Int>) throws -> [CodeBlockItemSyntax.Item] {
+    return try base.buildBasicBoundsChecks(&extractedCountArgs)
+  }
+  func buildCompoundBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
+    return try base.buildCompoundBoundsChecks()
   }
 
   func buildFunctionSignature(_ argTypes: [Int: TypeSyntax?], _ returnType: TypeSyntax?) throws
-    -> (FunctionSignatureSyntax, Bool)
+    -> FunctionSignatureSyntax
   {
     assert(returnType == nil)
     return try base.buildFunctionSignature(argTypes, newType)
@@ -545,14 +591,20 @@ struct CxxSpanReturnThunkBuilder: SpanBoundsThunkBuilder {
       } else {
         "MutableSpan"
       }
-    return "unsafe _cxxOverrideLifetime(\(raw: cast)(_unsafeCxxSpan: \(call)), copying: ())"
+    return "unsafe _swiftifyOverrideLifetime(\(raw: cast)(_unsafeCxxSpan: \(call)), copying: ())"
   }
 }
 
 protocol BoundsThunkBuilder: BoundsCheckedThunkBuilder {
   var oldType: TypeSyntax { get }
   var newType: TypeSyntax { get throws }
-  var signature: FunctionSignatureSyntax { get }
+  var funcDecl: FunctionParts { get }
+}
+
+extension BoundsThunkBuilder {
+  var signature: FunctionSignatureSyntax {
+    funcDecl.signature
+  }
 }
 
 protocol SpanBoundsThunkBuilder: BoundsThunkBuilder {
@@ -630,6 +682,10 @@ extension PointerBoundsThunkBuilder {
       return try transformType(oldType, generateSpan, isSizedBy, isParameter)
     }
   }
+
+  var countLabel: String {
+    return isSizedBy && generateSpan ? "byteCount" : "count"
+  }
 }
 
 protocol ParamBoundsThunkBuilder: BoundsThunkBuilder {
@@ -647,14 +703,14 @@ extension ParamBoundsThunkBuilder {
   }
 
   var name: TokenSyntax {
-    return param.secondName ?? param.firstName
+    param.name
   }
 }
 
 struct CountedOrSizedReturnPointerThunkBuilder: PointerBoundsThunkBuilder {
   public let base: BoundsCheckedThunkBuilder
   public let countExpr: ExprSyntax
-  public let signature: FunctionSignatureSyntax
+  public let funcDecl: FunctionParts
   public let nonescaping: Bool
   public let isSizedBy: Bool
   public let dependencies: [LifetimeDependence]
@@ -667,14 +723,17 @@ struct CountedOrSizedReturnPointerThunkBuilder: PointerBoundsThunkBuilder {
   }
 
   func buildFunctionSignature(_ argTypes: [Int: TypeSyntax?], _ returnType: TypeSyntax?) throws
-    -> (FunctionSignatureSyntax, Bool)
+    -> FunctionSignatureSyntax
   {
     assert(returnType == nil)
     return try base.buildFunctionSignature(argTypes, newType)
   }
 
-  func buildBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
-    return try base.buildBoundsChecks()
+  func buildBasicBoundsChecks(_ extractedCountArgs: inout Set<Int>) throws -> [CodeBlockItemSyntax.Item] {
+    return try base.buildBasicBoundsChecks(&extractedCountArgs)
+  }
+  func buildCompoundBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
+    return try base.buildCompoundBoundsChecks()
   }
 
   func buildFunctionCall(_ pointerArgs: [Int: ExprSyntax]) throws -> ExprSyntax {
@@ -686,25 +745,32 @@ struct CountedOrSizedReturnPointerThunkBuilder: PointerBoundsThunkBuilder {
         "start"
       }
     var cast = try newType
+    var expr: ExprSyntax
     if nullable {
       if let optType = cast.as(OptionalTypeSyntax.self) {
         cast = optType.wrappedType
       }
-      return """
-      { () in
-        let _resultValue = \(call)
-        if unsafe _resultValue == nil {
-          return nil
-        } else {
-          return unsafe \(raw: cast)(\(raw: startLabel): _resultValue!, count: Int(\(countExpr)))
-        }
-      }()
-      """
+      expr =
+        """
+        { () in
+          let _resultValue = \(call)
+          if unsafe _resultValue == nil {
+            return nil
+          } else {
+            return unsafe _swiftifyOverrideLifetime(\(raw: cast)(\(raw: startLabel): _resultValue!, \(raw: countLabel): Int(\(countExpr))), copying: ())
+          }
+        }()
+        """
+    } else {
+      expr =
+        """
+        \(raw: cast)(\(raw: startLabel): \(call), \(raw: countLabel): Int(\(countExpr)))
+        """
     }
-    return
-      """
-      unsafe \(raw: cast)(\(raw: startLabel): \(call), count: Int(\(countExpr)))
-      """
+    if generateSpan {
+      expr = "_swiftifyOverrideLifetime(\(expr), copying: ())"
+    }
+    return "unsafe \(expr)"
   }
 }
 
@@ -712,42 +778,60 @@ struct CountedOrSizedPointerThunkBuilder: ParamBoundsThunkBuilder, PointerBounds
   public let base: BoundsCheckedThunkBuilder
   public let index: Int
   public let countExpr: ExprSyntax
-  public let signature: FunctionSignatureSyntax
+  public let funcDecl: FunctionParts
   public let nonescaping: Bool
   public let isSizedBy: Bool
-  public let skipTrivialCount: Bool
   let isParameter: Bool = true
 
   var generateSpan: Bool { nonescaping }
 
   func buildFunctionSignature(_ argTypes: [Int: TypeSyntax?], _ returnType: TypeSyntax?) throws
-    -> (FunctionSignatureSyntax, Bool)
+    -> FunctionSignatureSyntax
   {
     var types = argTypes
     types[index] = try newType
-    if skipTrivialCount {
-      if let countVar = countExpr.as(DeclReferenceExprSyntax.self) {
-        let i = try getParameterIndexForDeclRef(signature.parameterClause.parameters, countVar)
-        types[i] = nil as TypeSyntax?
-      }
+    if let countVar = countExpr.as(DeclReferenceExprSyntax.self) {
+      let i = try getParameterIndexForDeclRef(signature.parameterClause.parameters, countVar)
+      types[i] = nil as TypeSyntax?
     }
     return try base.buildFunctionSignature(types, returnType)
   }
 
-  func buildBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
-    var res = try base.buildBoundsChecks()
-    let countName: TokenSyntax = "_\(raw: name)Count"
-    let count: VariableDeclSyntax = try VariableDeclSyntax(
-      "let \(countName): some BinaryInteger = \(countExpr)")
-    res.append(CodeBlockItemSyntax.Item(count))
-
-    let countCheck = ExprSyntax(
+  func checkBound(countName spanCount: ExprSyntax) -> StmtSyntax {
+    return
       """
-        if \(getCount()) < \(countName) || \(countName) < 0 {
-          fatalError("bounds check failure when calling unsafe function")
-        }
-      """)
-    res.append(CodeBlockItemSyntax.Item(countCheck))
+      if \(spanCount) != \(countExpr) {
+        fatalError("bounds check failure in \(funcDecl.name): expected \\(\(countExpr)) but got \\(\(spanCount))")
+      }
+      """
+  }
+
+  func buildBasicBoundsChecks(_ extractedCountArgs: inout Set<Int>) throws -> [CodeBlockItemSyntax.Item] {
+    var res = try base.buildBasicBoundsChecks(&extractedCountArgs)
+    if let countVar = countExpr.as(DeclReferenceExprSyntax.self) {
+      let i = try getParameterIndexForDeclRef(signature.parameterClause.parameters, countVar)
+      if extractedCountArgs.contains(i) {
+        res.append(CodeBlockItemSyntax.Item(checkBound(countName: makeCount())))
+      } else {
+        // this is the first parameter with this count parameter, nothing to compare against
+        let count = castIntToTargetType(expr: makeCount(), type: getParam(signature, i).type)
+        res.append(CodeBlockItemSyntax.Item(try VariableDeclSyntax(
+          "let \(countVar.baseName) = \(count)")))
+        extractedCountArgs.insert(i)
+      }
+    }
+    return res
+  }
+  func buildCompoundBoundsChecks() throws -> [CodeBlockItemSyntax.Item] {
+    var res = try base.buildCompoundBoundsChecks()
+
+    if !countExpr.is(DeclReferenceExprSyntax.self) {
+      let countName = ExprSyntax("_\(name)Count")
+      let count: VariableDeclSyntax = try VariableDeclSyntax(
+        "let \(countName) = \(makeCount())")
+      res.append(CodeBlockItemSyntax.Item(count))
+      res.append(CodeBlockItemSyntax.Item(checkBound(countName: countName)))
+    }
     return res
   }
 
@@ -773,13 +857,13 @@ struct CountedOrSizedPointerThunkBuilder: ParamBoundsThunkBuilder, PointerBounds
   }
 
   func buildUnwrapCall(_ argOverrides: [Int: ExprSyntax]) throws -> ExprSyntax {
-    let unwrappedName = TokenSyntax("_\(name)Ptr")
+    let unwrappedName = TokenSyntax("_\(name.withoutBackticks)Ptr").escapeIfNeeded
     var args = argOverrides
     let argExpr = ExprSyntax("\(unwrappedName).baseAddress")
     assert(args[index] == nil)
-    args[index] = try castPointerToOpaquePointer(unwrapIfNonnullable(argExpr))
+    args[index] = try castPointerToTargetType(unwrapIfNonnullable(argExpr))
     let call = try base.buildFunctionCall(args)
-    let ptrRef = unwrapIfNullable(ExprSyntax(DeclReferenceExprSyntax(baseName: name)))
+    let ptrRef = unwrapIfNullable("\(name)")
 
     let funcName =
       switch (isSizedBy, isMutablePointerType(oldType)) {
@@ -790,19 +874,26 @@ struct CountedOrSizedPointerThunkBuilder: ParamBoundsThunkBuilder, PointerBounds
       }
     let unwrappedCall = ExprSyntax(
       """
-        unsafe \(ptrRef).\(raw: funcName) { \(unwrappedName) in
-          return \(call)
-        }
+      unsafe \(ptrRef).\(raw: funcName) { \(unwrappedName) in
+        return \(call)
+      }
       """)
     return unwrappedCall
   }
 
-  func getCount() -> ExprSyntax {
-    let countName = isSizedBy && generateSpan ? "byteCount" : "count"
+  func makeCount() -> ExprSyntax {
+    let unsafeKw = generateSpan ? "" : "unsafe "
     if nullable {
-      return ExprSyntax("\(name)?.\(raw: countName) ?? 0")
+      return ExprSyntax("\(raw: unsafeKw)\(name)?.\(raw: countLabel) ?? 0")
     }
-    return ExprSyntax("\(name).\(raw: countName)")
+    return ExprSyntax("\(raw: unsafeKw)\(name).\(raw: countLabel)")
+  }
+
+  func getCountName() -> TokenSyntax {
+    if let countVar = countExpr.as(DeclReferenceExprSyntax.self) {
+      return countVar.baseName
+    }
+    return "_\(raw: name)Count"
   }
 
   func peelOptionalType(_ type: TypeSyntax) -> TypeSyntax {
@@ -815,12 +906,16 @@ struct CountedOrSizedPointerThunkBuilder: ParamBoundsThunkBuilder, PointerBounds
     return type
   }
 
-  func castPointerToOpaquePointer(_ baseAddress: ExprSyntax) throws -> ExprSyntax {
-    let i = try getParameterIndexForParamName(signature.parameterClause.parameters, name)
-    let type = peelOptionalType(getParam(signature, i).type)
+  func castPointerToTargetType(_ baseAddress: ExprSyntax) throws -> ExprSyntax {
+    let type = peelOptionalType(getParam(signature, index).type)
     if type.canRepresentBasicType(type: OpaquePointer.self) {
       return ExprSyntax("OpaquePointer(\(baseAddress))")
     }
+    if isSizedBy {
+      if let pointeeType = getPointeeType(type) {
+        return "\(baseAddress).assumingMemoryBound(to: \(pointeeType).self)"
+      }
+    }
     return baseAddress
   }
 
@@ -833,15 +928,6 @@ struct CountedOrSizedPointerThunkBuilder: ParamBoundsThunkBuilder, PointerBounds
 
   func buildFunctionCall(_ argOverrides: [Int: ExprSyntax]) throws -> ExprSyntax {
     var args = argOverrides
-    if skipTrivialCount {
-      assert(
-        countExpr.is(DeclReferenceExprSyntax.self) || countExpr.is(IntegerLiteralExprSyntax.self))
-      if let countVar = countExpr.as(DeclReferenceExprSyntax.self) {
-        let i = try getParameterIndexForDeclRef(signature.parameterClause.parameters, countVar)
-        assert(args[i] == nil)
-        args[i] = castIntToTargetType(expr: getCount(), type: getParam(signature, i).type)
-      }
-    }
     assert(args[index] == nil)
     if generateSpan {
       assert(nonescaping)
@@ -851,17 +937,17 @@ struct CountedOrSizedPointerThunkBuilder: ParamBoundsThunkBuilder, PointerBounds
         nullArgs[index] = ExprSyntax(NilLiteralExprSyntax(nilKeyword: .keyword(.nil)))
         return ExprSyntax(
           """
-            { () in return if \(name) == nil {
-                \(try base.buildFunctionCall(nullArgs))
-              } else {
-                \(unwrappedCall)
-              } }()
+          { () in return if \(name) == nil {
+              \(try base.buildFunctionCall(nullArgs))
+            } else {
+              \(unwrappedCall)
+            } }()
           """)
       }
       return unwrappedCall
     }
 
-    args[index] = try castPointerToOpaquePointer(getPointerArg())
+    args[index] = try castPointerToTargetType(getPointerArg())
     return try base.buildFunctionCall(args)
   }
 }
@@ -976,7 +1062,7 @@ func parseSwiftifyExpr(_ expr: ExprSyntax) throws -> SwiftifyExpr {
 }
 
 func parseCountedByEnum(
-  _ enumConstructorExpr: FunctionCallExprSyntax, _ signature: FunctionSignatureSyntax
+  _ enumConstructorExpr: FunctionCallExprSyntax, _ signature: FunctionSignatureSyntax, _ rewriter: CountExprRewriter
 ) throws -> ParamInfo {
   let argumentList = enumConstructorExpr.arguments
   let pointerExprArg = try getArgumentByName(argumentList, "pointer")
@@ -987,7 +1073,8 @@ func parseCountedByEnum(
       "expected string literal for 'count' parameter, got \(countExprArg)", node: countExprArg)
   }
   let unwrappedCountExpr = ExprSyntax(stringLiteral: countExprStringLit.representedLiteralValue!)
-  if let countVar = unwrappedCountExpr.as(DeclReferenceExprSyntax.self) {
+  let rewrittenCountExpr = rewriter.visit(unwrappedCountExpr)
+  if let countVar = rewrittenCountExpr.as(DeclReferenceExprSyntax.self) {
     // Perform this lookup here so we can override the position to point to the string literal
     // instead of line 1, column 1
     do {
@@ -997,11 +1084,11 @@ func parseCountedByEnum(
     }
   }
   return CountedBy(
-    pointerIndex: pointerExpr, count: unwrappedCountExpr, sizedBy: false,
+    pointerIndex: pointerExpr, count: rewrittenCountExpr, sizedBy: false,
     nonescaping: false, dependencies: [], original: ExprSyntax(enumConstructorExpr))
 }
 
-func parseSizedByEnum(_ enumConstructorExpr: FunctionCallExprSyntax) throws -> ParamInfo {
+func parseSizedByEnum(_ enumConstructorExpr: FunctionCallExprSyntax, _ rewriter: CountExprRewriter) throws -> ParamInfo {
   let argumentList = enumConstructorExpr.arguments
   let pointerExprArg = try getArgumentByName(argumentList, "pointer")
   let pointerExpr: SwiftifyExpr = try parseSwiftifyExpr(pointerExprArg)
@@ -1011,8 +1098,9 @@ func parseSizedByEnum(_ enumConstructorExpr: FunctionCallExprSyntax) throws -> P
       "expected string literal for 'size' parameter, got \(sizeExprArg)", node: sizeExprArg)
   }
   let unwrappedCountExpr = ExprSyntax(stringLiteral: sizeExprStringLit.representedLiteralValue!)
+  let rewrittenCountExpr = rewriter.visit(unwrappedCountExpr)
   return CountedBy(
-    pointerIndex: pointerExpr, count: unwrappedCountExpr, sizedBy: true, nonescaping: false,
+    pointerIndex: pointerExpr, count: rewrittenCountExpr, sizedBy: true, nonescaping: false,
     dependencies: [], original: ExprSyntax(enumConstructorExpr))
 }
 
@@ -1057,14 +1145,7 @@ func parseLifetimeDependence(_ enumConstructorExpr: FunctionCallExprSyntax) thro
   return (pointer, dependence)
 }
 
-func parseTypeMappingParam(_ paramAST: LabeledExprSyntax?) throws -> [String: String]? {
-  guard let unwrappedParamAST = paramAST else {
-    return nil
-  }
-  let paramExpr = unwrappedParamAST.expression
-  guard let dictExpr = paramExpr.as(DictionaryExprSyntax.self) else {
-    return nil
-  }
+func parseStringLiteralDict(_ dictExpr: DictionaryExprSyntax) throws -> [String: String] {
   var dict: [String: String] = [:]
   switch dictExpr.content {
   case .colon(_):
@@ -1086,6 +1167,45 @@ func parseTypeMappingParam(_ paramAST: LabeledExprSyntax?) throws -> [String: St
   return dict
 }
 
+func parseStringMappingParam(_ paramAST: LabeledExprSyntax?, paramName: String) throws -> [String: String]? {
+  guard let unwrappedParamAST = paramAST else {
+    return nil
+  }
+  guard let label = unwrappedParamAST.label else {
+    return nil
+  }
+  if label.trimmed.text != paramName {
+    return nil
+  }
+  let paramExpr = unwrappedParamAST.expression
+  guard let dictExpr = paramExpr.as(DictionaryExprSyntax.self) else {
+    return nil
+  }
+  return try parseStringLiteralDict(dictExpr)
+}
+
+func parseTypeMappingParam(_ paramAST: LabeledExprSyntax?) throws -> [String: String]? {
+  return try parseStringMappingParam(paramAST, paramName: "typeMappings")
+}
+
+func parseSpanAvailabilityParam(_ paramAST: LabeledExprSyntax?) throws -> String? {
+  guard let unwrappedParamAST = paramAST else {
+    return nil
+  }
+  guard let label = unwrappedParamAST.label else {
+    return nil
+  }
+  if label.trimmed.text != "spanAvailability" {
+    return nil
+  }
+  let paramExpr = unwrappedParamAST.expression
+  guard let stringLitExpr = paramExpr.as(StringLiteralExprSyntax.self) else {
+    throw DiagnosticError(
+      "expected a string literal, got '\(paramExpr)'", node: paramExpr)
+  }
+  return stringLitExpr.representedLiteralValue
+}
+
 func parseCxxSpansInSignature(
   _ signature: FunctionSignatureSyntax,
   _ typeMappings: [String: String]?
@@ -1117,7 +1237,7 @@ func parseCxxSpansInSignature(
 }
 
 func parseMacroParam(
-  _ paramAST: LabeledExprSyntax, _ signature: FunctionSignatureSyntax,
+  _ paramAST: LabeledExprSyntax, _ signature: FunctionSignatureSyntax, _ rewriter: CountExprRewriter,
   nonescapingPointers: inout Set<Int>,
   lifetimeDependencies: inout [SwiftifyExpr: [LifetimeDependence]]
 ) throws -> ParamInfo? {
@@ -1128,8 +1248,8 @@ func parseMacroParam(
   }
   let enumName = try parseEnumName(paramExpr)
   switch enumName {
-  case "countedBy": return try parseCountedByEnum(enumConstructorExpr, signature)
-  case "sizedBy": return try parseSizedByEnum(enumConstructorExpr)
+  case "countedBy": return try parseCountedByEnum(enumConstructorExpr, signature, rewriter)
+  case "sizedBy": return try parseSizedByEnum(enumConstructorExpr, rewriter)
   case "endedBy": return try parseEndedByEnum(enumConstructorExpr)
   case "nonescaping":
     let index = try parseNonEscaping(enumConstructorExpr)
@@ -1157,45 +1277,22 @@ func parseMacroParam(
   }
 }
 
-func hasTrivialCountVariants(_ parsedArgs: [ParamInfo]) -> Bool {
-  let countExprs = parsedArgs.compactMap {
-    switch $0 {
-    case let c as CountedBy: return c.count
-    default: return nil
-    }
-  }
-  let trivialCounts = countExprs.filter {
-    $0.is(DeclReferenceExprSyntax.self) || $0.is(IntegerLiteralExprSyntax.self)
-  }
-  // don't generate trivial count variants if there are any non-trivial counts
-  if trivialCounts.count < countExprs.count {
-    return false
-  }
-  let countVars = trivialCounts.filter { $0.is(DeclReferenceExprSyntax.self) }
-  let distinctCountVars = Set(
-    countVars.map {
-      return $0.as(DeclReferenceExprSyntax.self)!.baseName.text
-    })
-  // don't generate trivial count variants if two count expressions refer to the same parameter
-  return countVars.count == distinctCountVars.count
-}
-
-func checkArgs(_ args: [ParamInfo], _ funcDecl: FunctionDeclSyntax) throws {
+func checkArgs(_ args: [ParamInfo], _ funcComponents: FunctionParts) throws {
   var argByIndex: [Int: ParamInfo] = [:]
   var ret: ParamInfo? = nil
-  let paramCount = funcDecl.signature.parameterClause.parameters.count
+  let paramCount = funcComponents.signature.parameterClause.parameters.count
   try args.forEach { pointerInfo in
     switch pointerInfo.pointerIndex {
     case .param(let i):
       if i < 1 || i > paramCount {
         let noteMessage =
           paramCount > 0
-          ? "function \(funcDecl.name) has parameter indices 1..\(paramCount)"
-          : "function \(funcDecl.name) has no parameters"
+          ? "function \(funcComponents.name) has parameter indices 1..\(paramCount)"
+          : "function \(funcComponents.name) has no parameters"
         throw DiagnosticError(
           "pointer index out of bounds", node: pointerInfo.original,
           notes: [
-            Note(node: Syntax(funcDecl.name), message: MacroExpansionNoteMessage(noteMessage))
+            Note(node: Syntax(funcComponents.name), message: MacroExpansionNoteMessage(noteMessage))
           ])
       }
       if argByIndex[i] != nil {
@@ -1246,8 +1343,20 @@ func setLifetimeDependencies(
   }
 }
 
+func isInout(_ type: TypeSyntax) -> Bool {
+  guard let attr = type.as(AttributedTypeSyntax.self) else {
+    return false
+  }
+  return attr.specifiers.contains(where: { e in
+    guard let simpleSpec = e.as(SimpleTypeSpecifierSyntax.self) else {
+      return false
+    }
+    return simpleSpec.specifier.text == "inout"
+  })
+}
+
 func getReturnLifetimeAttribute(
-  _ funcDecl: FunctionDeclSyntax,
+  _ funcDecl: FunctionParts,
   _ dependencies: [SwiftifyExpr: [LifetimeDependence]]
 ) -> [AttributeListSyntax.Element] {
   let returnDependencies = dependencies[.`return`, default: []]
@@ -1258,10 +1367,14 @@ func getReturnLifetimeAttribute(
   for dependence in returnDependencies {
     switch dependence.type {
     case .borrow:
-      args.append(
-        LabeledExprSyntax(
-          expression:
-            DeclReferenceExprSyntax(baseName: TokenSyntax("borrow"))))
+      if isInout(getSwiftifyExprType(funcDecl, dependence.dependsOn)) {
+        args.append(LabeledExprSyntax(expression: ExprSyntax("&")))
+      } else {
+        args.append(
+          LabeledExprSyntax(
+            expression:
+              DeclReferenceExprSyntax(baseName: TokenSyntax("borrow"))))
+      }
     case .copy:
       args.append(
         LabeledExprSyntax(
@@ -1280,7 +1393,7 @@ func getReturnLifetimeAttribute(
     .attribute(
       AttributeSyntax(
         atSign: .atSignToken(),
-        attributeName: IdentifierTypeSyntax(name: "lifetime"),
+        attributeName: IdentifierTypeSyntax(name: "_lifetime"),
         leftParen: .leftParenToken(),
         arguments: .argumentList(LabeledExprListSyntax(args)),
         rightParen: .rightParenToken()))
@@ -1304,12 +1417,41 @@ func isMutableSpan(_ type: TypeSyntax) -> Bool {
   return name == "MutableSpan" || name == "MutableRawSpan"
 }
 
+func isAnySpan(_ type: TypeSyntax) -> Bool {
+  if let optType = type.as(OptionalTypeSyntax.self) {
+    return isAnySpan(optType.wrappedType)
+  }
+  if let impOptType = type.as(ImplicitlyUnwrappedOptionalTypeSyntax.self) {
+    return isAnySpan(impOptType.wrappedType)
+  }
+  if let attrType = type.as(AttributedTypeSyntax.self) {
+    return isAnySpan(attrType.baseType)
+  }
+  guard let identifierType = type.as(IdentifierTypeSyntax.self) else {
+    return false
+  }
+  let name = identifierType.name.text
+  return name == "Span" || name == "RawSpan" ||  name == "MutableSpan" || name == "MutableRawSpan"
+}
+
+func getAvailability(_ newSignature: FunctionSignatureSyntax, _ spanAvailability: String?)
+  throws -> [AttributeListSyntax.Element] {
+  guard let spanAvailability else {
+    return []
+  }
+  let returnIsSpan = newSignature.returnClause != nil && isAnySpan(newSignature.returnClause!.type)
+  if !returnIsSpan && !newSignature.parameterClause.parameters.contains(where: { isAnySpan($0.type) }) {
+    return []
+  }
+  return [.attribute(AttributeSyntax("@available(\(raw: spanAvailability), *)"))]
+}
+
 func containsLifetimeAttr(_ attrs: AttributeListSyntax, for paramName: TokenSyntax) -> Bool {
   for elem in attrs {
     guard let attr = elem.as(AttributeSyntax.self) else {
       continue
     }
-    if attr.attributeName != "lifetime" {
+    if attr.attributeName != "_lifetime" {
       continue
     }
     guard let args = attr.arguments?.as(LabeledExprListSyntax.self) else {
@@ -1333,7 +1475,7 @@ func paramLifetimeAttributes(
     if !isMutableSpan(param.type) {
       continue
     }
-    let paramName = param.secondName ?? param.firstName
+    let paramName = param.name
     if containsLifetimeAttr(oldAttrs, for: paramName) {
       continue
     }
@@ -1343,7 +1485,7 @@ func paramLifetimeAttributes(
       .attribute(
         AttributeSyntax(
           atSign: .atSignToken(),
-          attributeName: IdentifierTypeSyntax(name: "lifetime"),
+          attributeName: IdentifierTypeSyntax(name: "_lifetime"),
           leftParen: .leftParenToken(),
           arguments: .argumentList(LabeledExprListSyntax([LabeledExprSyntax(expression: expr)])),
           rightParen: .rightParenToken())))
@@ -1351,6 +1493,80 @@ func paramLifetimeAttributes(
   return defaultLifetimes
 }
 
+class CountExprRewriter: SyntaxRewriter {
+  public let nameMap: [String: String]
+
+  init(_ renamedParams: [String: String]) {
+    nameMap = renamedParams
+  }
+
+  override func visit(_ node: DeclReferenceExprSyntax) -> ExprSyntax {
+    if let newName = nameMap[node.baseName.trimmed.text] {
+      return ExprSyntax(
+        node.with(
+          \.baseName,
+          .identifier(
+            newName, leadingTrivia: node.baseName.leadingTrivia,
+            trailingTrivia: node.baseName.trailingTrivia)))
+    }
+    return escapeIfNeeded(node)
+  }
+}
+
+func renameParameterNamesIfNeeded(_ funcComponents: FunctionParts) -> (FunctionParts, CountExprRewriter) {
+  let params = funcComponents.signature.parameterClause.parameters
+  let funcName = funcComponents.name.withoutBackticks.trimmed.text
+  let shouldRename = params.contains(where: { param in
+    let paramName = param.name.trimmed.text
+    return paramName == "_" || paramName == funcName || "`\(paramName)`" == funcName
+  })
+  var renamedParams: [String: String] = [:]
+  let newParams = params.enumerated().map { (i, param) in
+    let secondName = if shouldRename {
+      // Including funcName in name prevents clash with function name.
+      // Renaming all parameters if one requires renaming guarantees that other parameters don't clash with the renamed one.
+      TokenSyntax("_\(raw: funcName)_param\(raw: i)")
+    } else {
+      param.secondName?.escapeIfNeeded
+    }
+    let firstName = param.firstName.escapeIfNeeded
+    let newParam = param.with(\.secondName, secondName)
+      .with(\.firstName, firstName)
+    let newName = newParam.name.trimmed.text
+    let oldName = param.name.trimmed.text
+    if newName != oldName {
+      renamedParams[oldName] = newName
+    }
+    return newParam
+  }
+  let newSig = if renamedParams.count > 0 {
+    funcComponents.signature.with(\.parameterClause.parameters, FunctionParameterListSyntax(newParams))
+  } else {
+    // Keeps source locations for diagnostics, in the common case where nothing was renamed
+    funcComponents.signature
+  }
+  return (FunctionParts(signature: newSig, name: funcComponents.name, attributes: funcComponents.attributes),
+          CountExprRewriter(renamedParams))
+}
+
+struct FunctionParts {
+  let signature: FunctionSignatureSyntax
+  let name: TokenSyntax
+  let attributes: AttributeListSyntax
+}
+
+func deconstructFunction(_ declaration: some DeclSyntaxProtocol) throws -> FunctionParts {
+  if let origFuncDecl = declaration.as(FunctionDeclSyntax.self) {
+    return FunctionParts(signature: origFuncDecl.signature, name: origFuncDecl.name,
+                         attributes: origFuncDecl.attributes)
+  }
+  if let origInitDecl = declaration.as(InitializerDeclSyntax.self) {
+    return FunctionParts(signature: origInitDecl.signature, name: origInitDecl.initKeyword,
+                         attributes: origInitDecl.attributes)
+  }
+  throw DiagnosticError("@_SwiftifyImport only works on functions and initializers", node: declaration)
+}
+
 /// A macro that adds safe(r) wrappers for functions with unsafe pointer types.
 /// Depends on bounds, escapability and lifetime information for each pointer.
 /// Intended to map to C attributes like __counted_by, __ended_by and __no_escape,
@@ -1364,9 +1580,8 @@ public struct SwiftifyImportMacro: PeerMacro {
     in context: some MacroExpansionContext
   ) throws -> [DeclSyntax] {
     do {
-      guard let funcDecl = declaration.as(FunctionDeclSyntax.self) else {
-        throw DiagnosticError("@_SwiftifyImport only works on functions", node: declaration)
-      }
+      let origFuncComponents = try deconstructFunction(declaration)
+      let (funcComponents, rewriter) = renameParameterNamesIfNeeded(origFuncComponents)
 
       let argumentList = node.arguments!.as(LabeledExprListSyntax.self)!
       var arguments = [LabeledExprSyntax](argumentList)
@@ -1374,14 +1589,18 @@ public struct SwiftifyImportMacro: PeerMacro {
       if typeMappings != nil {
         arguments = arguments.dropLast()
       }
+      let spanAvailability = try parseSpanAvailabilityParam(arguments.last)
+      if spanAvailability != nil {
+        arguments = arguments.dropLast()
+      }
       var nonescapingPointers = Set<Int>()
       var lifetimeDependencies: [SwiftifyExpr: [LifetimeDependence]] = [:]
       var parsedArgs = try arguments.compactMap {
         try parseMacroParam(
-          $0, funcDecl.signature, nonescapingPointers: &nonescapingPointers,
+          $0, funcComponents.signature, rewriter, nonescapingPointers: &nonescapingPointers,
           lifetimeDependencies: &lifetimeDependencies)
       }
-      parsedArgs.append(contentsOf: try parseCxxSpansInSignature(funcDecl.signature, typeMappings))
+      parsedArgs.append(contentsOf: try parseCxxSpansInSignature(funcComponents.signature, typeMappings))
       setNonescapingPointers(&parsedArgs, nonescapingPointers)
       setLifetimeDependencies(&parsedArgs, lifetimeDependencies)
       // We only transform non-escaping spans.
@@ -1392,7 +1611,7 @@ public struct SwiftifyImportMacro: PeerMacro {
           return true
         }
       }
-      try checkArgs(parsedArgs, funcDecl)
+      try checkArgs(parsedArgs, funcComponents)
       parsedArgs.sort { a, b in
         // make sure return value cast to Span happens last so that withUnsafeBufferPointer
         // doesn't return a ~Escapable type
@@ -1404,46 +1623,45 @@ public struct SwiftifyImportMacro: PeerMacro {
         }
         return paramOrReturnIndex(a.pointerIndex) < paramOrReturnIndex(b.pointerIndex)
       }
-      let baseBuilder = FunctionCallBuilder(funcDecl)
-
-      let skipTrivialCount = hasTrivialCountVariants(parsedArgs)
+      let baseBuilder = FunctionCallBuilder(funcComponents)
 
       let builder: BoundsCheckedThunkBuilder = parsedArgs.reduce(
         baseBuilder,
         { (prev, parsedArg) in
-          parsedArg.getBoundsCheckedThunkBuilder(prev, funcDecl, skipTrivialCount)
+          parsedArg.getBoundsCheckedThunkBuilder(prev, funcComponents)
         })
-      let (newSignature, onlyReturnTypeChanged) = try builder.buildFunctionSignature([:], nil)
-      let checks =
-        skipTrivialCount
-        ? [] as [CodeBlockItemSyntax]
-        : try builder.buildBoundsChecks().map { e in
-          CodeBlockItemSyntax(leadingTrivia: "\n", item: e)
-        }
-      let call = CodeBlockItemSyntax(
-        item: CodeBlockItemSyntax.Item(
-          ReturnStmtSyntax(
-            returnKeyword: .keyword(.return, trailingTrivia: " "),
-            expression: try builder.buildFunctionCall([:]))))
+      let newSignature = try builder.buildFunctionSignature([:], nil)
+      var eliminatedArgs = Set<Int>()
+      let basicChecks = try builder.buildBasicBoundsChecks(&eliminatedArgs)
+      let compoundChecks = try builder.buildCompoundBoundsChecks()
+      let checks = (basicChecks + compoundChecks).map { e in
+        CodeBlockItemSyntax(leadingTrivia: "\n", item: e)
+      }
+      var call : CodeBlockItemSyntax
+      if declaration.is(InitializerDeclSyntax.self) {
+        call = CodeBlockItemSyntax(
+          item: CodeBlockItemSyntax.Item(
+              try builder.buildFunctionCall([:])))
+      } else {
+        call = CodeBlockItemSyntax(
+          item: CodeBlockItemSyntax.Item(
+            ReturnStmtSyntax(
+              returnKeyword: .keyword(.return, trailingTrivia: " "),
+              expression: try builder.buildFunctionCall([:]))))
+      }
       let body = CodeBlockSyntax(statements: CodeBlockItemListSyntax(checks + [call]))
-      let returnLifetimeAttribute = getReturnLifetimeAttribute(funcDecl, lifetimeDependencies)
+      let returnLifetimeAttribute = getReturnLifetimeAttribute(funcComponents, lifetimeDependencies)
       let lifetimeAttrs =
-        returnLifetimeAttribute + paramLifetimeAttributes(newSignature, funcDecl.attributes)
+        returnLifetimeAttribute + paramLifetimeAttributes(newSignature, funcComponents.attributes)
+      let availabilityAttr = try getAvailability(newSignature, spanAvailability)
       let disfavoredOverload: [AttributeListSyntax.Element] =
-        (onlyReturnTypeChanged
-          ? [
-            .attribute(
-              AttributeSyntax(
-                atSign: .atSignToken(),
-                attributeName: IdentifierTypeSyntax(name: "_disfavoredOverload")))
-          ] : [])
-      let newFunc =
-        funcDecl
-        .with(\.signature, newSignature)
-        .with(\.body, body)
-        .with(
-          \.attributes,
-          funcDecl.attributes.filter { e in
+        [
+          .attribute(
+            AttributeSyntax(
+              atSign: .atSignToken(),
+              attributeName: IdentifierTypeSyntax(name: "_disfavoredOverload")))
+        ]
+      let attributes = funcComponents.attributes.filter { e in
             switch e {
             case .attribute(let attr):
               // don't apply this macro recursively, and avoid dupe _alwaysEmitIntoClient
@@ -1457,9 +1675,25 @@ public struct SwiftifyImportMacro: PeerMacro {
                 atSign: .atSignToken(),
                 attributeName: IdentifierTypeSyntax(name: "_alwaysEmitIntoClient")))
           ]
+            + availabilityAttr
             + lifetimeAttrs
-            + disfavoredOverload)
-      return [DeclSyntax(newFunc)]
+            + disfavoredOverload
+      let trivia = node.leadingTrivia + .docLineComment("/// This is an auto-generated wrapper for safer interop\n")
+      if let origFuncDecl = declaration.as(FunctionDeclSyntax.self) {
+        return [DeclSyntax(origFuncDecl
+                  .with(\.signature, newSignature)
+                  .with(\.body, body)
+                  .with(\.attributes, AttributeListSyntax(attributes))
+                  .with(\.leadingTrivia, trivia))]
+      } 
+      if let origInitDecl = declaration.as(InitializerDeclSyntax.self) {
+        return [DeclSyntax(origInitDecl
+                  .with(\.signature, newSignature)
+                  .with(\.body, body)
+                  .with(\.attributes, AttributeListSyntax(attributes))
+                  .with(\.leadingTrivia, trivia))]
+      }
+      return []
     } catch let error as DiagnosticError {
       context.diagnose(
         Diagnostic(
@@ -1515,3 +1749,36 @@ extension TypeSyntaxProtocol {
     return false
   }
 }
+
+extension FunctionParameterSyntax {
+  var name: TokenSyntax {
+    self.secondName ?? self.firstName
+  }
+}
+
+extension TokenSyntax {
+  public var withoutBackticks: TokenSyntax {
+    if self.identifier == nil {
+      return self
+    }
+    return .identifier(self.identifier!.name)
+  }
+
+  public var escapeIfNeeded: TokenSyntax {
+    var parser = Parser("let \(self)")
+    let decl = DeclSyntax.parse(from: &parser)
+    if !decl.hasError {
+      return self
+    } else {
+      return self.copyTrivia(to: "`\(raw: self.trimmed.text)`")
+    }
+  }
+
+  public func copyTrivia(to other: TokenSyntax) -> TokenSyntax {
+    return .identifier(other.text, leadingTrivia: self.leadingTrivia, trailingTrivia: self.trailingTrivia)
+  }
+}
+
+func escapeIfNeeded(_ identifier: DeclReferenceExprSyntax) -> ExprSyntax {
+  return "\(identifier.baseName.escapeIfNeeded)"
+}
diff --git a/lib/Macros/Sources/SwiftMacros/TaskMacro.swift b/lib/Macros/Sources/SwiftMacros/TaskMacro.swift
deleted file mode 100644
index 53baf1fd13b11..0000000000000
--- a/lib/Macros/Sources/SwiftMacros/TaskMacro.swift
+++ /dev/null
@@ -1,126 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2025 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import SwiftDiagnostics
-import SwiftParser
-import SwiftSyntax
-import SwiftSyntaxBuilder
-import SwiftSyntaxMacros
-
-extension MacroExpansionContext {
-  func diagnose(
-    _ diag: TaskMacroDiagnostic,
-    at node: some SyntaxProtocol
-  ) {
-    diagnose(Diagnostic(
-      node: Syntax(node),
-      message: diag
-    ))
-  }
-}
-
-enum TaskMacroDiagnostic: String, DiagnosticMessage {
-  case noImplementation 
-    = "'@Task' macro can only be used on functions with an implementation"
-  case unsupportedGlobalActor
-    = "'@Task' global actor must be written 'GlobalActorType'.shared"
-
-  var message: String { rawValue }
-
-  var severity: DiagnosticSeverity { .error }
-
-  var diagnosticID: MessageID {
-    MessageID(domain: "_Concurrency", id: "TaskMacro.\(self)")
-  }
-}
-
-
-public struct TaskMacro: BodyMacro {
-  public static func expansion(
-    of node: AttributeSyntax,
-    statements: CodeBlockItemListSyntax,
-    in context: some MacroExpansionContext
-  ) throws -> [CodeBlockItemSyntax] {
-    var globalActor: TokenSyntax? = nil
-    var argumentList: LabeledExprListSyntax = []
-    if case .argumentList(let arguments) = node.arguments {
-      if let actor = arguments.first(labeled: "on") {
-        guard let member = actor.expression.as(MemberAccessExprSyntax.self),
-              let declRef = member.base?.as(DeclReferenceExprSyntax.self) else {
-          context.diagnose(.unsupportedGlobalActor, at: actor)
-          return []
-        }
-
-        argumentList = LabeledExprListSyntax(arguments.dropFirst())
-        globalActor = declRef.baseName
-      } else {
-        argumentList = arguments
-      }
-    }
-
-    let signature: ClosureSignatureSyntax? =
-      if let globalActor {
-        .init(attributes: "@\(globalActor) ")
-      } else {
-        nil
-      }
-
-    let parens: (left: TokenSyntax, right: TokenSyntax)? =
-      if !argumentList.isEmpty {
-        (.leftParenToken(), .rightParenToken())
-      } else {
-        nil
-      }
-
-    let taskInit = FunctionCallExprSyntax(
-      calledExpression: DeclReferenceExprSyntax(
-        baseName: "Task"
-      ),
-      leftParen: parens?.left,
-      arguments: argumentList,
-      rightParen: parens?.right,
-      trailingClosure: ClosureExprSyntax(
-        signature: signature,
-        statements: statements
-      )
-    )
-
-    return ["\(taskInit)"]
-  }
-
-  public static func expansion(
-    of node: AttributeSyntax,
-    providingBodyFor declaration: some DeclSyntaxProtocol & WithOptionalCodeBlockSyntax,
-    in context: some MacroExpansionContext
-  ) throws -> [CodeBlockItemSyntax] {
-    guard let taskBody = declaration.body else {
-      context.diagnose(.noImplementation, at: node)
-      return []
-    }
-
-    return try expansion(
-      of: node,
-      statements: taskBody.statements,
-      in: context)
-  }
-
-  public static func expansion(
-    of node: AttributeSyntax,
-    providingBodyFor closure: ClosureExprSyntax,
-    in context: some MacroExpansionContext
-  ) throws -> [CodeBlockItemSyntax] {
-    try expansion(
-      of: node,
-      statements: closure.statements,
-      in: context)
-  }
-}
diff --git a/lib/Markup/AST.cpp b/lib/Markup/AST.cpp
index 2c94e1d49306e..92994f9ccc181 100644
--- a/lib/Markup/AST.cpp
+++ b/lib/Markup/AST.cpp
@@ -25,7 +25,7 @@ using namespace markup;
 Document::Document(ArrayRef<MarkupASTNode*> Children)
     : MarkupASTNode(ASTNodeKind::Document), NumChildren(Children.size()) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 Document *Document::create(MarkupContext &MC,
@@ -38,7 +38,7 @@ Document *Document::create(MarkupContext &MC,
 BlockQuote::BlockQuote(ArrayRef<MarkupASTNode*> Children)
     : MarkupASTNode(ASTNodeKind::BlockQuote), NumChildren(Children.size()) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 BlockQuote *BlockQuote::create(MarkupContext &MC, ArrayRef<MarkupASTNode *> Children) {
@@ -72,7 +72,7 @@ List::List(ArrayRef<MarkupASTNode *> Children, bool IsOrdered)
     : MarkupASTNode(ASTNodeKind::List), NumChildren(Children.size()),
       Ordered(IsOrdered) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 List *List::create(MarkupContext &MC, ArrayRef<MarkupASTNode *> Children,
@@ -85,7 +85,7 @@ List *List::create(MarkupContext &MC, ArrayRef<MarkupASTNode *> Children,
 Item::Item(ArrayRef<MarkupASTNode*> Children)
     : MarkupASTNode(ASTNodeKind::Item), NumChildren(Children.size()) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 Item *Item::create(MarkupContext &MC, ArrayRef<MarkupASTNode *> Children) {
@@ -98,7 +98,7 @@ Link::Link(StringRef Destination, ArrayRef<MarkupASTNode *> Children)
     : InlineContent(ASTNodeKind::Link), NumChildren(Children.size()),
       Destination(Destination) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 Link *Link::create(MarkupContext &MC, StringRef Destination,
@@ -114,7 +114,7 @@ Image::Image(StringRef Destination, std::optional<StringRef> Title,
     : InlineContent(ASTNodeKind::Image), NumChildren(Children.size()),
       Destination(Destination), Title(Title) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 Image *Image::create(MarkupContext &MC, StringRef Destination,
@@ -133,7 +133,7 @@ Header::Header(unsigned Level, ArrayRef<MarkupASTNode *> Children)
     : MarkupASTNode(ASTNodeKind::Header), NumChildren(Children.size()),
       Level(Level) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 Header *Header::create(MarkupContext &MC, unsigned Level,
@@ -147,7 +147,7 @@ Paragraph::Paragraph(ArrayRef<MarkupASTNode *> Children)
     : MarkupASTNode(ASTNodeKind::Paragraph),
       NumChildren(Children.size()) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 Paragraph *Paragraph::create(MarkupContext &MC,
@@ -158,7 +158,8 @@ Paragraph *Paragraph::create(MarkupContext &MC,
 }
 
 InlineAttributes::InlineAttributes(StringRef Attributes, ArrayRef<MarkupASTNode *> Children) : InlineContent(ASTNodeKind::InlineAttributes), NumChildren(Children.size()), Attributes(Attributes) {
-  std::uninitialized_copy(Children.begin(), Children.end(), getTrailingObjects<MarkupASTNode *>());
+  std::uninitialized_copy(Children.begin(), Children.end(),
+                          getTrailingObjects());
 }
 
 InlineAttributes *InlineAttributes::create(MarkupContext &MC, StringRef Attributes, ArrayRef<MarkupASTNode *> Children) {
@@ -190,7 +191,7 @@ LineBreak *LineBreak::create(MarkupContext &MC) {
 Emphasis::Emphasis(ArrayRef<MarkupASTNode *> Children)
     : InlineContent(ASTNodeKind::Emphasis), NumChildren(Children.size()) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 Emphasis *Emphasis::create(MarkupContext &MC,
@@ -203,7 +204,7 @@ Emphasis *Emphasis::create(MarkupContext &MC,
 Strong::Strong(ArrayRef<MarkupASTNode *> Children)
     : InlineContent(ASTNodeKind::Strong), NumChildren(Children.size()) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 Strong *Strong::create(MarkupContext &MC,
@@ -217,7 +218,7 @@ ParamField::ParamField(StringRef Name, ArrayRef<MarkupASTNode *> Children)
     : PrivateExtension(ASTNodeKind::ParamField), NumChildren(Children.size()),
       Name(Name), Parts(std::nullopt) {
   std::uninitialized_copy(Children.begin(), Children.end(),
-                          getTrailingObjects<MarkupASTNode *>());
+                          getTrailingObjects());
 }
 
 ParamField *ParamField::create(MarkupContext &MC, StringRef Name,
@@ -237,7 +238,7 @@ Id *Id::create(MarkupContext &MC, ArrayRef<MarkupASTNode *> Children) { \
 Id::Id(ArrayRef<MarkupASTNode *> Children) \
     : PrivateExtension(ASTNodeKind::Id), NumChildren(Children.size()) { \
   std::uninitialized_copy(Children.begin(), Children.end(), \
-                          getTrailingObjects<MarkupASTNode *>()); \
+                          getTrailingObjects()); \
 }
 #include "swift/Markup/SimpleFields.def"
 
diff --git a/lib/Migrator/APIDiffMigratorPass.cpp b/lib/Migrator/APIDiffMigratorPass.cpp
index 042a6e13bc1a0..17ce0e7916f7e 100644
--- a/lib/Migrator/APIDiffMigratorPass.cpp
+++ b/lib/Migrator/APIDiffMigratorPass.cpp
@@ -29,7 +29,7 @@
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Edit/EditedSource.h"
-#include "clang/Rewrite/Core/RewriteBuffer.h"
+#include "llvm/ADT/RewriteBuffer.h"
 #include "llvm/Support/FileSystem.h"
 
 using namespace swift;
@@ -162,6 +162,10 @@ class ChildIndexFinder : public TypeReprVisitor<ChildIndexFinder, FoundResult> {
     return visit(T->getBase());
   }
 
+  FoundResult visitCallerIsolatedTypeRepr(CallerIsolatedTypeRepr *T) {
+    return visit(T->getBase());
+  }
+
   FoundResult visitArrayTypeRepr(ArrayTypeRepr *T) {
     return handleParent(T, T->getBase());
   }
@@ -464,16 +468,18 @@ struct APIDiffMigratorPass : public ASTMigratorPass, public SourceEntityWalker {
     }
   }
 
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef,
-                          Type T, ReferenceMetaData Data) override {
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type T,
+                          ReferenceMetaData Data) override {
+    CharSourceRange CharRange = Lexer::getCharSourceRangeFromSourceRange(
+        D->getASTContext().SourceMgr, Range);
     if (Data.isImplicit)
       return true;
 
     for (auto *Item: getRelatedDiffItems(CtorTyRef ? CtorTyRef: D)) {
       std::string RepText;
-      if (isSimpleReplacement(Item, isDotMember(Range), RepText)) {
-        Editor.replace(Range, RepText);
+      if (isSimpleReplacement(Item, isDotMember(CharRange), RepText)) {
+        Editor.replace(CharRange, RepText);
         return true;
       }
     }
@@ -484,11 +490,12 @@ struct APIDiffMigratorPass : public ASTMigratorPass, public SourceEntityWalker {
     ValueDecl *Target;
     CharSourceRange Result;
     ReferenceCollector(ValueDecl* Target) : Target(Target) {}
-    bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
+    bool visitDeclReference(ValueDecl *D, SourceRange Range,
                             TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef,
                             Type T, ReferenceMetaData Data) override {
       if (D == Target && !Data.isImplicit && Range.isValid()) {
-        Result = Range;
+        Result = Lexer::getCharSourceRangeFromSourceRange(
+            D->getASTContext().SourceMgr, Range);
         return false;
       }
       return true;
@@ -1396,10 +1403,10 @@ struct APIDiffMigratorPass : public ASTMigratorPass, public SourceEntityWalker {
     PreWalkResult<Stmt *> walkToStmtPre(Stmt *S) override {
       if (auto *BS = dyn_cast<BraceStmt>(S)) {
         for(auto Ele: BS->getElements()) {
-          if (Ele.is<Expr*>() && isSuperExpr(Ele.get<Expr*>())) {
+          if (isa<Expr *>(Ele) && isSuperExpr(cast<Expr *>(Ele))) {
             Editor.remove(Ele.getSourceRange());
           }
-	}
+        }
       }
       // We only handle top-level expressions, so avoid visiting further.
       return Action::SkipNode(S);
diff --git a/lib/Migrator/Migrator.cpp b/lib/Migrator/Migrator.cpp
index 7549d14200480..857e30eb3dead 100644
--- a/lib/Migrator/Migrator.cpp
+++ b/lib/Migrator/Migrator.cpp
@@ -21,7 +21,7 @@
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Edit/EditedSource.h"
-#include "clang/Rewrite/Core/RewriteBuffer.h"
+#include "llvm/ADT/RewriteBuffer.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
 
@@ -191,11 +191,11 @@ bool Migrator::performSyntacticPasses(SyntacticPassOptions Opts) {
   llvm::IntrusiveRefCntPtr<clang::DiagnosticIDs> DummyClangDiagIDs {
     new clang::DiagnosticIDs()
   };
-  auto ClangDiags =
-    std::make_unique<clang::DiagnosticsEngine>(DummyClangDiagIDs,
-                                                new clang::DiagnosticOptions,
-                                                new clang::DiagnosticConsumer(),
-                                                /*ShouldOwnClient=*/true);
+
+  clang::DiagnosticOptions diagOpts;
+  auto ClangDiags = std::make_unique<clang::DiagnosticsEngine>(
+      DummyClangDiagIDs, diagOpts, new clang::DiagnosticConsumer(),
+      /*ShouldOwnClient=*/true);
 
   clang::SourceManager ClangSourceManager { *ClangDiags, ClangFileManager };
   clang::LangOptions ClangLangOpts;
diff --git a/lib/Option/Options.cpp b/lib/Option/Options.cpp
index 6a159de3150ba..5a334e131bcc1 100644
--- a/lib/Option/Options.cpp
+++ b/lib/Option/Options.cpp
@@ -16,15 +16,16 @@
 #include "llvm/Option/OptTable.h"
 #include "llvm/Option/Option.h"
 
-using namespace swift::options;
-using namespace llvm::opt;
+#define OPTTABLE_STR_TABLE_CODE
+#include "swift/Option/Options.inc"
+#undef OPTTABLE_STR_TABLE_CODE
 
-#define PREFIX(NAME, VALUE)                                                    \
-  constexpr llvm::StringLiteral NAME##_init[] = VALUE;                         \
-  constexpr llvm::ArrayRef<llvm::StringLiteral> NAME(                          \
-      NAME##_init, std::size(NAME##_init) - 1);
+#define OPTTABLE_PREFIXES_TABLE_CODE
 #include "swift/Option/Options.inc"
-#undef PREFIX
+#undef OPTTABLE_PREFIXES_TABLE_CODE
+
+using namespace swift::options;
+using namespace llvm::opt;
 
 static const llvm::opt::GenericOptTable::Info InfoTable[] = {
 #define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
@@ -36,7 +37,8 @@ namespace {
 
 class SwiftOptTable : public llvm::opt::GenericOptTable {
 public:
-  SwiftOptTable() : GenericOptTable(InfoTable) {}
+  SwiftOptTable()
+      : GenericOptTable(OptionStrTable, OptionPrefixesTable, InfoTable) {}
 };
 
 } // end anonymous namespace
diff --git a/lib/Option/SanitizerOptions.cpp b/lib/Option/SanitizerOptions.cpp
index f8f8ccbb4bb19..1c10d69d4a539 100644
--- a/lib/Option/SanitizerOptions.cpp
+++ b/lib/Option/SanitizerOptions.cpp
@@ -168,7 +168,7 @@ OptionSet<SanitizerKind> swift::parseSanitizerArgValues(
   }
 
   // Check that we're one of the known supported targets for sanitizers.
-  if (!(Triple.isOSDarwin() || Triple.isOSLinux() || Triple.isOSWindows())) {
+  if (!(Triple.isOSDarwin() || Triple.isOSLinux() || Triple.isOSWindows() || Triple.isOSWASI() || Triple.isOSFreeBSD())) {
     SmallString<128> b;
     Diags.diagnose(SourceLoc(), diag::error_unsupported_opt_for_target,
       (A->getOption().getPrefixedName() +
diff --git a/lib/Option/features.json b/lib/Option/features.json
index 4bef4b444b0d5..7d521787a4dd8 100644
--- a/lib/Option/features.json
+++ b/lib/Option/features.json
@@ -47,6 +47,12 @@
     },
     {
        "name": "experimental-package-interface-load"
+    },
+    {
+       "name": "Isystem"
+    },
+    {
+       "name": "internal-import-bridging-header"
     }
   ]
 }
diff --git a/lib/Parse/Lexer.cpp b/lib/Parse/Lexer.cpp
index a1e3b467e2f9a..4529466531afd 100644
--- a/lib/Parse/Lexer.cpp
+++ b/lib/Parse/Lexer.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -348,7 +348,7 @@ Lexer::State Lexer::getStateForBeginningOfTokenLoc(SourceLoc Loc) const {
     }
     break;
   }
-  return State(SourceLoc(llvm::SMLoc::getFromPointer(Ptr)));
+  return State(SourceLoc::getFromPointer(Ptr));
 }
 
 //===----------------------------------------------------------------------===//
@@ -660,8 +660,8 @@ static bool advanceIfValidContinuationOfOperator(char const *&ptr,
 
 /// Returns true if the given string is entirely whitespace (considering only
 /// those whitespace code points permitted in raw identifiers).
-static bool isEntirelyWhitespace(StringRef string) {
-  if (string.empty()) return false;
+static bool isEscapedIdentifierEntirelyWhitespace(StringRef string) {
+  if (string.empty()) return true;
   char const *p = string.data(), *end = string.end();
   if (!advanceIf(p, end, isPermittedRawIdentifierWhitespace))
     return false;
@@ -703,7 +703,7 @@ bool Lexer::isValidAsEscapedIdentifier(StringRef string) {
     ;
   if (p != end)
     return false;
-  return !isEntirelyWhitespace(string);
+  return !isEscapedIdentifierEntirelyWhitespace(string);
 }
 
 /// Determines if the given string is a valid operator identifier,
@@ -2315,7 +2315,8 @@ void Lexer::lexEscapedIdentifier() {
   // If we have the terminating "`", it's an escaped/raw identifier, unless it
   // contained only operator characters or was entirely whitespace.
   StringRef IdStr(IdentifierStart, CurPtr - IdentifierStart);
-  if (*CurPtr == '`' && !isOperator(IdStr) && !isEntirelyWhitespace(IdStr)) {
+  if (*CurPtr == '`' && !isOperator(IdStr) &&
+      !isEscapedIdentifierEntirelyWhitespace(IdStr)) {
     ++CurPtr;
     formEscapedIdentifierToken(Quote);
     return;
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index b3a4319d904ba..bc964de53936e 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -560,7 +560,7 @@ ParserResult<AvailableAttr> Parser::parseExtendedAvailabilitySpecList(
 }
 
 bool Parser::parseSpecializeAttributeArguments(
-    swift::tok ClosingBrace, bool &DiscardAttribute,
+    swift::tok ClosingBrace, bool isPublic, bool &DiscardAttribute,
     std::optional<bool> &Exported,
     std::optional<SpecializeAttr::SpecializationKind> &Kind,
     swift::TrailingWhereClause *&TrailingWhereClause,
@@ -580,11 +580,22 @@ bool Parser::parseSpecializeAttributeArguments(
           ParamLabel != "spiModule" && ParamLabel != "availability" &&
           (!isSIL || ParamLabel != "available")) {
         diagnose(Tok.getLoc(), diag::attr_specialize_unknown_parameter_name,
+                 ParamLabel, isPublic);
+      }
+
+      // The non-underscored '@specialize' mode currently does not support any
+      // parameters.
+      if (isPublic) {
+        diagnose(Tok.getLoc(), diag::attr_specialize_unsupported_parameter_name,
                  ParamLabel);
+        DiscardAttribute = true;
+        return false;
       }
+
       auto AtLoc = consumeToken();
       if (!consumeIf(tok::colon)) {
-        diagnose(Tok.getLoc(), diag::attr_specialize_missing_colon, ParamLabel);
+        diagnose(Tok.getLoc(), diag::attr_specialize_missing_colon, ParamLabel,
+                 isPublic);
         skipUntil(tok::comma, tok::kw_where);
         if (Tok.is(ClosingBrace))
           break;
@@ -602,7 +613,7 @@ bool Parser::parseSpecializeAttributeArguments(
           (ParamLabel == "kind" && Kind.has_value()) ||
           (ParamLabel == "spi" && !spiGroups.empty())) {
         diagnose(Tok.getLoc(), diag::attr_specialize_parameter_already_defined,
-                 ParamLabel);
+                 ParamLabel, isPublic);
       }
       if (ParamLabel == "available") {
         SourceRange range;
@@ -628,7 +639,7 @@ bool Parser::parseSpecializeAttributeArguments(
         bool isTrue = consumeIf(tok::kw_true);
         bool isFalse = consumeIf(tok::kw_false);
         if (!isTrue && !isFalse) {
-          diagnose(Tok.getLoc(), diag::attr_specialize_expected_bool_value);
+          diagnose(Tok.getLoc(), diag::attr_specialize_expected_bool_value, isPublic);
           skipUntil(tok::comma, tok::kw_where);
           if (Tok.is(ClosingBrace))
             break;
@@ -678,7 +689,7 @@ bool Parser::parseSpecializeAttributeArguments(
       if (ParamLabel == "spiModule") {
         if (!parseSILSIPModule(*this)) {
           diagnose(Tok.getLoc(), diag::attr_specialize_unknown_parameter_name,
-                   ParamLabel);
+                   ParamLabel, isPublic);
           return false;
         }
       }
@@ -693,7 +704,7 @@ bool Parser::parseSpecializeAttributeArguments(
         consumeToken();
       }
       if (!isAvailability && !consumeIf(tok::comma)) {
-        diagnose(Tok.getLoc(), diag::attr_specialize_missing_comma);
+        diagnose(Tok.getLoc(), diag::attr_specialize_missing_comma, isPublic);
         skipUntil(tok::comma, tok::kw_where);
         if (Tok.is(ClosingBrace))
           break;
@@ -710,6 +721,7 @@ bool Parser::parseSpecializeAttributeArguments(
       continue;
     }
     diagnose(Tok.getLoc(),
+             isPublic ?  diag::attr_specialized_missing_where_clause :
              diag::attr_specialize_missing_parameter_label_or_where_clause);
     DiscardAttribute = true;
     return false;
@@ -720,7 +732,7 @@ bool Parser::parseSpecializeAttributeArguments(
     SourceLoc whereLoc, endLoc;
     SmallVector<RequirementRepr, 4> requirements;
     parseGenericWhereClause(whereLoc, endLoc, requirements,
-                            /* AllowLayoutConstraints */ true);
+                            /* AllowLayoutConstraints */ !isPublic);
     TrailingWhereClause =
         TrailingWhereClause::create(Context, whereLoc, endLoc, requirements);
   }
@@ -858,14 +870,14 @@ bool Parser::parseAvailability(
 }
 
 bool Parser::parseSpecializeAttribute(
-    swift::tok ClosingBrace, SourceLoc AtLoc, SourceLoc Loc,
-    SpecializeAttr *&Attr, AvailabilityRange *SILAvailability,
+    swift::tok ClosingBrace, SourceLoc AtLoc, SourceLoc Loc, bool isPublic,
+    AbstractSpecializeAttr *&Attr, AvailabilityRange *SILAvailability,
     llvm::function_ref<bool(Parser &)> parseSILTargetName,
     llvm::function_ref<bool(Parser &)> parseSILSIPModule) {
   assert(ClosingBrace == tok::r_paren || ClosingBrace == tok::r_square);
 
   SourceLoc lParenLoc;
-  if (Tok.is(tok::l_paren)) {
+  if (isAtAttributeLParen()) {
     lParenLoc = consumeAttributeLParen();
   } else {
     // SIL parsing is positioned at _specialize when entering this and parses
@@ -873,7 +885,7 @@ bool Parser::parseSpecializeAttribute(
     lParenLoc = consumeToken();
   }
   bool DiscardAttribute = false;
-  StringRef AttrName = "_specialize";
+  StringRef AttrName = isPublic ? "specialized" : "_specialize";
 
   std::optional<bool> exported;
   std::optional<SpecializeAttr::SpecializationKind> kind;
@@ -884,7 +896,8 @@ bool Parser::parseSpecializeAttribute(
   SmallVector<Identifier, 4> spiGroups;
   SmallVector<AvailableAttr *, 4> availableAttrs;
   if (!parseSpecializeAttributeArguments(
-          ClosingBrace, DiscardAttribute, exported, kind, trailingWhereClause,
+          ClosingBrace, isPublic, DiscardAttribute, exported, kind,
+          trailingWhereClause,
           targetFunction, SILAvailability, spiGroups, availableAttrs,
           parseSILTargetName, parseSILSIPModule)) {
     return false;
@@ -914,10 +927,17 @@ bool Parser::parseSpecializeAttribute(
   }  
 
   // Store the attribute.
-  Attr = SpecializeAttr::create(Context, AtLoc, SourceRange(Loc, rParenLoc),
-                                trailingWhereClause, exported.value(),
-                                kind.value(), targetFunction, spiGroups,
-                                availableAttrs);
+  if (isPublic)
+    Attr = SpecializedAttr::create(Context, AtLoc,
+                                  SourceRange(Loc, rParenLoc),
+                                  trailingWhereClause, exported.value(),
+                                  kind.value(), targetFunction, spiGroups,
+                                  availableAttrs);
+  else
+    Attr = SpecializeAttr::create(Context, AtLoc, SourceRange(Loc, rParenLoc),
+                                  trailingWhereClause, exported.value(),
+                                  kind.value(), targetFunction, spiGroups,
+                                  availableAttrs);
   return true;
 }
 
@@ -2137,7 +2157,7 @@ Parser::parseAttributeArguments(SourceLoc attrLoc, StringRef attrName,
   }
 
   return parseList(tok::r_paren, parensRange.Start, parensRange.End,
-                   /*allow sep after last*/ true,
+                   /*AllowSepAfterLast=*/true,
                    {diag::attr_expected_rparen, {attrName, isModifier}},
                    parseArg);
 }
@@ -2241,7 +2261,7 @@ Parser::parseMacroRoleAttribute(
     break;
   }
 
-  if (!Tok.isFollowingLParen()) {
+  if (!isAtAttributeLParen()) {
     diagnose(Tok, diag::attr_expected_lparen, attrName, false);
     return makeParserError();
   }
@@ -2483,7 +2503,7 @@ static std::optional<Identifier> parseSingleAttrOptionImpl(
   };
   bool isDeclModifier = DeclAttribute::isDeclModifier(DK);
 
-  if (!P.Tok.is(tok::l_paren)) {
+  if (!P.isAtAttributeLParen()) {
     if (allowOmitted)
       return Identifier();
 
@@ -2564,29 +2584,23 @@ parseLifetimeDescriptor(Parser &P,
   }
 }
 
-ParserResult<LifetimeAttr> Parser::parseLifetimeAttribute(SourceLoc atLoc,
+ParserResult<LifetimeAttr> Parser::parseLifetimeAttribute(StringRef attrName,
+                                                          SourceLoc atLoc,
                                                           SourceLoc loc) {
   ParserStatus status;
-  if (!Context.LangOpts.hasFeature(Feature::LifetimeDependence) &&
-      !Context.SourceMgr.isImportMacroGeneratedLoc(atLoc)) {
-    diagnose(loc, diag::requires_experimental_feature, "@lifetime", false,
-             getFeatureName(Feature::LifetimeDependence));
-    status.setIsParseError();
-    return status;
-  }
 
   auto lifetimeEntry = parseLifetimeEntry(loc);
   if (lifetimeEntry.isNull()) {
     status.setIsParseError();
     return status;
   }
+
   return ParserResult<LifetimeAttr>(LifetimeAttr::create(
       Context, atLoc, SourceRange(loc, lifetimeEntry.get()->getEndLoc()),
-      /* implicit */ false, lifetimeEntry.get()));
+      /* implicit */ false, lifetimeEntry.get(),
+      attrName.compare("_lifetime") == 0));
 }
 
-
-
 /// Parses a (possibly optional) argument for an attribute containing a single, arbitrary identifier.
 ///
 /// \param P The parser object.
@@ -2771,7 +2785,8 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
     auto kind = parseSingleAttrOption<InlineKind>(
         *this, Loc, AttrRange, AttrName, DK, {
           { Context.Id_never,   InlineKind::Never },
-          { Context.Id__always, InlineKind::Always }
+          { Context.Id_always,  InlineKind::Always },
+          { Context.Id__always, InlineKind::AlwaysUnderscored }
         });
     if (!kind)
       return makeParserSuccess();
@@ -2869,7 +2884,7 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
       .Case("public", AccessLevel::Public)
       .Case("open", AccessLevel::Open);
 
-    if (!Tok.is(tok::l_paren)) {
+    if (!isAtAttributeLParen()) {
       // Normal access control attribute.
       AttrRange = Loc;
 
@@ -2894,7 +2909,7 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
       break;
     }
 
-    consumeAttributeLParen();
+    auto LParenLoc = consumeAttributeLParen();
 
     if (Tok.is(tok::code_complete)) {
       if (CodeCompletionCallbacks) {
@@ -2906,27 +2921,42 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
     }
     
     // Parse the subject.
-    if (Tok.isContextualKeyword("set")) {
-      consumeToken();
-    } else {
-      diagnose(Loc, diag::attr_access_expected_set, AttrName);
+    if (!Tok.isContextualKeyword("set")) {
+      auto diag = diagnose(Loc, diag::attr_access_expected_set, AttrName);
 
-      // Minimal recovery: if there's a single token and then an r_paren,
-      // consume them both. If there's just an r_paren, consume that.
-      if (!consumeIf(tok::r_paren)) {
-        if (Tok.isNot(tok::l_paren) && peekToken().is(tok::r_paren)) {
-          consumeToken();
-          consumeToken(tok::r_paren);
-        }
+      if (Tok.is(tok::r_paren)) {
+        // Suggest `set` between empty parens e.g. `private()` -> `private(set)`
+        auto SetLoc = consumeToken(tok::r_paren);
+        diag.fixItInsert(SetLoc, "set");
+      } else if (!Tok.is(tok::l_paren) && peekToken().is(tok::r_paren)) {
+        // Suggest `set` in place of an invalid token between parens
+        // e.g. `private(<invalid>)` -> `private(set)`
+        auto SetLoc = consumeToken();
+        diag.fixItReplace(SetLoc, "set");
+        consumeToken(tok::r_paren);
+      } else if (isNextStartOfSwiftDecl()) {
+        // Suggest `set)` in place of an invalid token after l_paren followed by
+        // a valid declaration start.
+        // e.g. `private(<invalid> var x: Int` -> `private(set) var x: Int`
+        auto SetLoc = consumeToken();
+        diag.fixItReplace(SetLoc, "set)");
+      } else {
+        // Suggest `set)` after l_paren if not followed by a valid declaration
+        // e.g. `private( <invalid>` -> `private(set) <invalid>`
+        diag.fixItInsertAfter(LParenLoc, "set)");
       }
+
       return makeParserSuccess();
     }
 
+    auto SubjectLoc = consumeToken();
+
     AttrRange = SourceRange(Loc, Tok.getLoc());
 
     if (!consumeIf(tok::r_paren)) {
       diagnose(Loc, diag::attr_expected_rparen, AttrName,
-               DeclAttribute::isDeclModifier(DK));
+               DeclAttribute::isDeclModifier(DK))
+          .fixItInsertAfter(SubjectLoc, ")");
       return makeParserSuccess();
     }
 
@@ -2994,7 +3024,45 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
     break;
   }
 
-  case DeclAttrKind::CDecl:
+  case DeclAttrKind::CDecl: {
+    if (!AttrName.starts_with("_") &&
+
+        // Backwards support for @c("stringId"). Remove before enabling in
+        // production so we accept only the identifier format.
+        lookahead<bool>(1, [&](CancellableBacktrackingScope &) {
+           return Tok.isNot(tok::string_literal);
+        })) {
+
+      std::optional<StringRef> CName;
+      if (consumeIfAttributeLParen()) {
+        // Custom C name.
+        if (Tok.isNot(tok::identifier)) {
+          diagnose(Loc, diag::attr_expected_cname, AttrName);
+          return makeParserSuccess();
+        }
+
+        CName = Tok.getText();
+        consumeToken(tok::identifier);
+        AttrRange = SourceRange(Loc, Tok.getRange().getStart());
+
+        if (!consumeIf(tok::r_paren)) {
+          diagnose(Loc, diag::attr_expected_rparen, AttrName,
+                   DeclAttribute::isDeclModifier(DK));
+          return makeParserSuccess();
+        }
+      } else {
+        AttrRange = SourceRange(Loc);
+      }
+
+      Attributes.add(new (Context) CDeclAttr(CName.value_or(StringRef()), AtLoc,
+                                             AttrRange, /*Implicit=*/false,
+                                             /*isUnderscored*/false));
+      break;
+    }
+
+    // Leave legacy @_cdecls to the logic expecting a string.
+    LLVM_FALLTHROUGH;
+  }
   case DeclAttrKind::Expose:
   case DeclAttrKind::SILGenName: {
     if (!consumeIfAttributeLParen()) {
@@ -3012,13 +3080,22 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
                  "Cxx");
         ParseSymbolName = false;
       };
+      bool isNegated = false;
+      if (Tok.is(tok::oper_prefix) && Tok.getText() == "!") {
+        isNegated = true;
+        consumeToken(tok::oper_prefix);
+      }
       if (Tok.isNot(tok::identifier)) {
         diagnoseExpectOption();
         return makeParserSuccess();
       }
       if (Tok.getText() == "Cxx") {
-        ExpKind = ExposureKind::Cxx;
+        ExpKind = isNegated ? ExposureKind::NotCxx : ExposureKind::Cxx;
       } else if (Tok.getText() == "wasm") {
+        if (isNegated) {
+          diagnoseExpectOption();
+          return makeParserSuccess();
+        }
         ExpKind = ExposureKind::Wasm;
       } else {
         diagnoseExpectOption();
@@ -3074,10 +3151,12 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
       if (DK == DeclAttrKind::SILGenName)
         Attributes.add(new (Context) SILGenNameAttr(AsmName.value(), Raw, AtLoc,
                                                 AttrRange, /*Implicit=*/false));
-      else if (DK == DeclAttrKind::CDecl)
+      else if (DK == DeclAttrKind::CDecl) {
+        bool underscored = AttrName.starts_with("_");
         Attributes.add(new (Context) CDeclAttr(AsmName.value(), AtLoc,
-                                               AttrRange, /*Implicit=*/false));
-      else if (DK == DeclAttrKind::Expose) {
+                                               AttrRange, /*Implicit=*/false,
+                                               /*isUnderscored*/underscored));
+      } else if (DK == DeclAttrKind::Expose) {
         for (auto *EA : Attributes.getAttributes<ExposeAttr>()) {
           // A single declaration cannot have two @_exported attributes with
           // the same exposure kind.
@@ -3243,7 +3322,8 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
     StringRef AttrName = "@_originallyDefinedIn";
     bool SuppressLaterDiags = false;
     bool ParsedUnrecognizedPlatformName = false;
-    if (parseList(tok::r_paren, LeftLoc, RightLoc, false,
+    if (parseList(tok::r_paren, LeftLoc, RightLoc,
+                  /*AllowSepAfterLast=*/false,
                   diag::originally_defined_in_missing_rparen,
                   [&]() -> ParserStatus {
       SWIFT_DEFER {
@@ -3357,9 +3437,18 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
     }
 
     if (abiDecl) {
-      Attributes.add(new (Context) ABIAttr(abiDecl,
-                                           AtLoc, { Loc, rParenLoc },
-                                           /*implicit=*/false));
+      auto attr = new (Context) ABIAttr(abiDecl, AtLoc, { Loc, rParenLoc },
+                                        /*implicit=*/false);
+
+      // Diagnose syntactically invalid abiDecl kind here to match behavior of
+      // Swift parser.
+      if (!attr->canAppearOnDecl(abiDecl) && !isa<PatternBindingDecl>(abiDecl)){
+        diagnose(abiDecl->getLoc(), diag::attr_abi_incompatible_kind,
+                 abiDecl->getDescriptiveKind());
+        attr->setInvalid();
+      }
+
+      Attributes.add(attr);
     }
 
     break;
@@ -3379,7 +3468,7 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
   }
   case DeclAttrKind::PrivateImport: {
     // Parse the leading '('.
-    if (Tok.isNot(tok::l_paren)) {
+    if (!isAtAttributeLParen()) {
       diagnose(Loc, diag::attr_expected_lparen, AttrName,
                DeclAttribute::isDeclModifier(DK));
       return makeParserSuccess();
@@ -3428,7 +3517,7 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
   }
   case DeclAttrKind::ObjC: {
     // Unnamed @objc attribute.
-    if (Tok.isNot(tok::l_paren)) {
+    if (!isAtAttributeLParen()) {
       auto attr = ObjCAttr::createUnnamed(Context, AtLoc, Loc);
       Attributes.add(attr);
       break;
@@ -3496,7 +3585,7 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
 
   case DeclAttrKind::DynamicReplacement: {
     // Parse the leading '('.
-    if (Tok.isNot(tok::l_paren)) {
+    if (!isAtAttributeLParen()) {
       diagnose(Loc, diag::attr_expected_lparen, AttrName,
                DeclAttribute::isDeclModifier(DK));
       return makeParserSuccess();
@@ -3547,7 +3636,7 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
 
   case DeclAttrKind::TypeEraser: {
     // Parse leading '('
-    if (Tok.isNot(tok::l_paren)) {
+    if (!isAtAttributeLParen()) {
       diagnose(Loc, diag::attr_expected_lparen, AttrName,
                DeclAttribute::isDeclModifier(DK));
       return makeParserSuccess();
@@ -3575,14 +3664,17 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
     break;
   }
 
-  case DeclAttrKind::Specialize: {
-    if (Tok.isNot(tok::l_paren)) {
+  case DeclAttrKind::Specialize:
+  case DeclAttrKind::Specialized: {
+    if (!isAtAttributeLParen()) {
       diagnose(Loc, diag::attr_expected_lparen, AttrName,
                DeclAttribute::isDeclModifier(DK));
       return makeParserSuccess();
     }
-    SpecializeAttr *Attr;
-    if (!parseSpecializeAttribute(tok::r_paren, AtLoc, Loc, Attr, nullptr))
+    AbstractSpecializeAttr *Attr;
+    if (!parseSpecializeAttribute(tok::r_paren, AtLoc, Loc,
+                                  DK == DeclAttrKind::Specialized, Attr,
+                                  nullptr))
       return makeParserSuccess();
 
     Attributes.add(Attr);
@@ -3744,23 +3836,43 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
   }
   case DeclAttrKind::Nonisolated: {
     AttrRange = Loc;
-    std::optional<bool> isUnsafe(false);
+    std::optional<NonIsolatedModifier> Modifier(NonIsolatedModifier::None);
     if (EnableParameterizedNonisolated) {
-      isUnsafe =
-          parseSingleAttrOption<bool>(*this, Loc, AttrRange, AttrName, DK,
-                                      {{Context.Id_unsafe, true}}, *isUnsafe,
-                                      ParameterizedDeclAttributeKind::Nonisolated);
-      if (!isUnsafe) {
+      Modifier = parseSingleAttrOption<NonIsolatedModifier>(
+          *this, Loc, AttrRange, AttrName, DK,
+          {{Context.Id_unsafe, NonIsolatedModifier::Unsafe},
+           {Context.Id_nonsending, NonIsolatedModifier::NonSending}},
+          *Modifier, ParameterizedDeclAttributeKind::Nonisolated);
+      if (!Modifier) {
         return makeParserSuccess();
       }
     }
 
     if (!DiscardAttribute) {
-      Attributes.add(new (Context) NonisolatedAttr(AtLoc, AttrRange, *isUnsafe,
+      Attributes.add(new (Context) NonisolatedAttr(AtLoc, AttrRange, *Modifier,
                                                    /*implicit*/ false));
     }
     break;
   }
+  case DeclAttrKind::InheritActorContext: {
+    AttrRange = Loc;
+    std::optional<InheritActorContextModifier> Modifier(
+        InheritActorContextModifier::None);
+    Modifier = parseSingleAttrOption<InheritActorContextModifier>(
+        *this, Loc, AttrRange, AttrName, DK,
+        {{Context.Id_always, InheritActorContextModifier::Always}}, *Modifier,
+        ParameterizedDeclAttributeKind::InheritActorContext);
+    if (!Modifier) {
+      return makeParserSuccess();
+    }
+
+    if (!DiscardAttribute) {
+      Attributes.add(new (Context) InheritActorContextAttr(
+          AtLoc, AttrRange, *Modifier, /*implicit=*/false));
+    }
+
+    break;
+  }
   case DeclAttrKind::MacroRole: {
     auto syntax = (AttrName == "freestanding" ? MacroSyntax::Freestanding
                                               : MacroSyntax::Attached);
@@ -3783,7 +3895,7 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
     break;
   }
   case DeclAttrKind::RawLayout: {
-    if (Tok.isNot(tok::l_paren)) {
+    if (!isAtAttributeLParen()) {
       diagnose(Loc, diag::attr_expected_lparen, AttrName,
                DeclAttribute::isDeclModifier(DK));
       return makeParserSuccess();
@@ -3940,24 +4052,24 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
     break;
   }
   case DeclAttrKind::Lifetime: {
-    auto Attr = parseLifetimeAttribute(AtLoc, Loc);
+    auto Attr = parseLifetimeAttribute(AttrName, AtLoc, Loc);
     Status |= Attr;
     if (Attr.isNonNull())
       Attributes.add(Attr.get());
     break;
   }
 
-  case DeclAttrKind::Execution: {
-    auto behavior = parseSingleAttrOption<ExecutionKind>(
+  case DeclAttrKind::Nonexhaustive: {
+    auto mode = parseSingleAttrOption<NonexhaustiveMode>(
         *this, Loc, AttrRange, AttrName, DK,
-        {{Context.Id_concurrent, ExecutionKind::Concurrent},
-         {Context.Id_caller, ExecutionKind::Caller}});
-    if (!behavior)
+        {{Context.Id_warn, NonexhaustiveMode::Warning}},
+        NonexhaustiveMode::Error,
+        ParameterizedDeclAttributeKind::Nonexhaustive);
+    if (!mode)
       return makeParserSuccess();
 
     if (!DiscardAttribute)
-      Attributes.add(new (Context) ExecutionAttr(AtLoc, AttrRange, *behavior,
-                                                 /*Implicit*/ false));
+      Attributes.add(new (Context) NonexhaustiveAttr(AtLoc, AttrRange, *mode));
 
     break;
   }
@@ -4053,27 +4165,11 @@ bool Parser::parseVersionTuple(llvm::VersionTuple &Version,
   return false;
 }
 
-bool Parser::isCustomAttributeArgument() {
-  BacktrackingScope backtrack(*this);
-  if (skipSingle().hasCodeCompletion())
-    return true;
-
-  // If we have any keyword, identifier, or token that follows a function
-  // type's parameter list, this is a parameter list and not an attribute.
-  // Alternatively, we might have a token that illustrates we're not going to
-  // get anything following the attribute, which means the parentheses describe
-  // what follows the attribute.
-  return !Tok.isAny(
-      tok::arrow, tok::kw_throw, tok::kw_throws, tok::kw_rethrows,
-      tok::r_paren, tok::r_brace, tok::r_square, tok::r_angle) &&
-    !Tok.isContextualKeyword("async") && !Tok.isContextualKeyword("reasync") ;
-}
-
 bool Parser::canParseCustomAttribute() {
   if (!canParseType())
     return false;
 
-  if (Tok.isFollowingLParen() && isCustomAttributeArgument())
+  if (isAtAttributeLParen(/*isCustomAttribute=*/true))
     skipSingle();
 
   return true;
@@ -4085,7 +4181,7 @@ ParserResult<CustomAttr> Parser::parseCustomAttribute(SourceLoc atLoc) {
   // Parse a custom attribute.
   auto type = parseType(diag::expected_type, ParseTypeReason::CustomAttribute);
   if (type.hasCodeCompletion() || type.isNull()) {
-    if (Tok.is(tok::l_paren) && isCustomAttributeArgument())
+    if (isAtAttributeLParen(/*isCustomAttribute=*/true))
       skipSingle();
 
     return ParserResult<CustomAttr>(ParserStatus(type));
@@ -4097,7 +4193,11 @@ ParserResult<CustomAttr> Parser::parseCustomAttribute(SourceLoc atLoc) {
   ParserStatus status;
   ArgumentList *argList = nullptr;
   CustomAttributeInitializer *initContext = nullptr;
-  if (Tok.isFollowingLParen() && isCustomAttributeArgument()) {
+  if (isAtAttributeLParen(/*isCustomAttribute=*/true)) {
+    if (getEndOfPreviousLoc() != Tok.getLoc()) {
+      diagnose(getEndOfPreviousLoc(), diag::attr_extra_whitespace_before_lparen)
+          .warnUntilSwiftVersion(6);
+    }
     // If we have no local context to parse the initial value into, create
     // one for the attribute.
     std::optional<ParseFunctionBody> initParser;
@@ -4106,10 +4206,6 @@ ParserResult<CustomAttr> Parser::parseCustomAttribute(SourceLoc atLoc) {
       initContext = CustomAttributeInitializer::create(CurDeclContext);
       initParser.emplace(*this, initContext);
     }
-    if (getEndOfPreviousLoc() != Tok.getLoc()) {
-      diagnose(getEndOfPreviousLoc(), diag::attr_extra_whitespace_before_lparen)
-          .warnUntilSwiftVersion(6);
-    }
     auto result = parseArgumentList(tok::l_paren, tok::r_paren,
                                     /*isExprBasic*/ true,
                                     /*allowTrailingClosure*/ false);
@@ -4246,10 +4342,6 @@ ParserStatus Parser::parseDeclAttribute(DeclAttributes &Attributes,
   checkInvalidAttrName("_functionBuilder", "resultBuilder",
                        DeclAttrKind::ResultBuilder, diag::attr_renamed_warning);
 
-  // Historical name for @Sendable.
-  checkInvalidAttrName("concurrent", "Sendable", DeclAttrKind::Sendable,
-                       diag::attr_renamed_warning);
-
   // Historical name for 'nonisolated'.
   if (!DK && Tok.getText() == "actorIndependent") {
     diagnose(
@@ -4271,7 +4363,7 @@ ParserStatus Parser::parseDeclAttribute(DeclAttributes &Attributes,
     SourceLoc attrLoc = consumeToken();
 
     // @warn_unused_result with no arguments.
-    if (Tok.isNot(tok::l_paren)) {
+    if (!isAtAttributeLParen()) {
       diagnose(AtLoc, diag::attr_warn_unused_result_removed)
         .fixItRemove(SourceRange(AtLoc, attrLoc));
 
@@ -4343,7 +4435,7 @@ ParserStatus Parser::parseDeclAttribute(DeclAttributes &Attributes,
   if (TypeAttribute::getAttrKindFromString(Tok.getText()).has_value())
     diagnose(Tok, diag::type_attribute_applied_to_decl);
   else if (Tok.isContextualKeyword("unknown")) {
-    diagnose(Tok, diag::unknown_attribute, "unknown");
+    diagnose(Tok, diag::unknown_attr_name, "unknown");
   } else {
     // Change the context to create a custom attribute syntax.
     auto customAttr = parseCustomAttribute(AtLoc);
@@ -4355,7 +4447,7 @@ ParserStatus Parser::parseDeclAttribute(DeclAttributes &Attributes,
 
   // Recover by eating @foo(...) when foo is not known.
   consumeToken();
-  if (Tok.is(tok::l_paren))
+  if (isAtAttributeLParen())
     skipSingle();
 
   return makeParserError();
@@ -4603,23 +4695,6 @@ ParserStatus Parser::parseTypeAttribute(TypeOrCustomAttr &result,
   // Determine which attribute it is, and diagnose it if unknown.
   auto optAttr = TypeAttribute::getAttrKindFromString(Tok.getText());
 
-  auto checkInvalidAttrName =
-      [&](StringRef invalidName, StringRef correctName, TypeAttrKind kind,
-          std::optional<Diag<StringRef, StringRef>> diag = std::nullopt) {
-        if (!optAttr && Tok.getText() == invalidName) {
-          optAttr = kind;
-
-          if (diag) {
-            diagnose(Tok, *diag, invalidName, correctName)
-                .fixItReplace(Tok.getLoc(), correctName);
-          }
-        }
-      };
-
-  // Historical name for @Sendable.
-  checkInvalidAttrName("concurrent", "Sendable", TypeAttrKind::Sendable,
-                       diag::attr_renamed_warning);
-
   if (!optAttr) {
     auto declAttrID = DeclAttribute::getAttrKindFromString(Tok.getText());
     if (declAttrID) {
@@ -4655,15 +4730,8 @@ ParserStatus Parser::parseTypeAttribute(TypeOrCustomAttr &result,
       // Recover by eating @foo(...) when foo is not known.
       consumeToken();
 
-      if (Tok.is(tok::l_paren) && getEndOfPreviousLoc() == Tok.getLoc()) {
-        CancellableBacktrackingScope backtrack(*this);
+      if (isAtAttributeLParen(/*isCustomAttr=*/true))
         skipSingle();
-        // If we found '->', or 'throws' after paren, it's likely a parameter
-        // of function type.
-        if (Tok.isNot(tok::arrow, tok::kw_throws, tok::kw_rethrows,
-                      tok::kw_throw))
-          backtrack.cancelBacktrack();
-      }
 
       return makeParserError();
     }
@@ -4713,7 +4781,7 @@ ParserStatus Parser::parseTypeAttribute(TypeOrCustomAttr &result,
         } else {
           // We could use diag::only_allowed_in_sil here, but it's better
           // not to mention SIL in general diagnostics.
-          diagnose(AtLoc, diag::unknown_attribute, Text);
+          diagnose(AtLoc, diag::unknown_attr_name, Text);
         }
       }
       return makeParserSuccess();
@@ -4724,7 +4792,7 @@ ParserStatus Parser::parseTypeAttribute(TypeOrCustomAttr &result,
 
   case TypeAttrKind::Isolated: {
     SourceLoc lpLoc = Tok.getLoc(), kindLoc, rpLoc;
-    if (!consumeIfNotAtStartOfLine(tok::l_paren)) {
+    if (!consumeIfAttributeLParen()) {
       if (!justChecking) {
         diagnose(Tok, diag::attr_isolated_expected_lparen);
         // TODO: should we suggest removing the `@`?
@@ -4769,60 +4837,10 @@ ParserStatus Parser::parseTypeAttribute(TypeOrCustomAttr &result,
     return makeParserSuccess();
   }
 
-  case TypeAttrKind::Execution: {
-    if (!Context.LangOpts.hasFeature(Feature::ExecutionAttribute)) {
-      diagnose(Tok, diag::requires_experimental_feature, "@execution", false,
-               getFeatureName(Feature::ExecutionAttribute));
-      return makeParserError();
-    }
-
-    SourceLoc lpLoc = Tok.getLoc(), behaviorLoc, rpLoc;
-    if (!consumeIfNotAtStartOfLine(tok::l_paren)) {
-      if (!justChecking) {
-        diagnose(Tok, diag::attr_execution_expected_lparen);
-        // TODO: should we suggest removing the `@`?
-      }
-      return makeParserError();
-    }
-
-    bool invalid = false;
-    std::optional<ExecutionKind> behavior;
-    if (isIdentifier(Tok, "concurrent")) {
-      behaviorLoc = consumeToken(tok::identifier);
-      behavior = ExecutionKind::Concurrent;
-    } else if (isIdentifier(Tok, "caller")) {
-      behaviorLoc = consumeToken(tok::identifier);
-      behavior = ExecutionKind::Caller;
-    } else {
-      if (!justChecking) {
-        diagnose(Tok, diag::attr_execution_expected_kind);
-      }
-      invalid = true;
-      consumeIf(tok::identifier);
-    }
-
-    if (justChecking && !Tok.is(tok::r_paren))
-      return makeParserError();
-    if (parseMatchingToken(tok::r_paren, rpLoc,
-                           diag::attr_execution_expected_rparen,
-                           lpLoc))
-      return makeParserError();
-
-    if (invalid)
-      return makeParserError();
-    assert(behavior);
-
-    if (!justChecking) {
-      result = new (Context) ExecutionTypeAttr(AtLoc, attrLoc, {lpLoc, rpLoc},
-                                               {*behavior, behaviorLoc});
-    }
-    return makeParserSuccess();
-  }
-
   case TypeAttrKind::Opened: {
     // Parse the opened existential ID string in parens
     SourceLoc beginLoc = Tok.getLoc(), idLoc, endLoc;
-    if (!consumeAttributeLParen()) {
+    if (!consumeIfAttributeLParen()) {
       if (!justChecking)
         diagnose(Tok, diag::opened_attribute_expected_lparen);
       return makeParserError();
@@ -5019,12 +5037,17 @@ ParserResult<LifetimeEntry> Parser::parseLifetimeEntry(SourceLoc loc) {
     if (Tok.isContextualKeyword("borrow") &&
         peekToken().isAny(tok::identifier, tok::integer_literal,
                           tok::kw_self)) {
-      return ParsedLifetimeDependenceKind::Scope;
+      return ParsedLifetimeDependenceKind::Borrow;
+    }
+    if (Tok.is(tok::amp_prefix) &&
+        peekToken().isAny(tok::identifier, tok::integer_literal,
+                          tok::kw_self)) {
+      return ParsedLifetimeDependenceKind::Inout;
     }
     return std::nullopt;
   };
 
-  if (!Tok.isFollowingLParen()) {
+  if (!isAtAttributeLParen()) {
     diagnose(loc, diag::expected_lparen_after_lifetime_dependence);
     status.setIsParseError();
     return status;
@@ -5046,8 +5069,9 @@ ParserResult<LifetimeEntry> Parser::parseLifetimeEntry(SourceLoc loc) {
   SmallVector<LifetimeDescriptor> sources;
   SourceLoc rParenLoc;
   bool foundParamId = false;
+  bool invalidSourceDescriptor = false;
   status = parseList(
-      tok::r_paren, lParenLoc, rParenLoc, /*AllowSepAfterLast*/ false,
+      tok::r_paren, lParenLoc, rParenLoc, /*AllowSepAfterLast=*/false,
       diag::expected_rparen_after_lifetime_dependence, [&]() -> ParserStatus {
         ParserStatus listStatus;
         foundParamId = true;
@@ -5062,6 +5086,7 @@ ParserResult<LifetimeEntry> Parser::parseLifetimeEntry(SourceLoc loc) {
         auto sourceDescriptor =
             parseLifetimeDescriptor(*this, lifetimeDependenceKind);
         if (!sourceDescriptor) {
+          invalidSourceDescriptor = true;
           listStatus.setIsParseError();
           return listStatus;
         }
@@ -5069,6 +5094,10 @@ ParserResult<LifetimeEntry> Parser::parseLifetimeEntry(SourceLoc loc) {
         return listStatus;
       });
 
+  if (invalidSourceDescriptor) {
+    status.setIsParseError();
+    return status;
+  }
   if (!foundParamId) {
     diagnose(
         Tok,
@@ -5316,6 +5345,7 @@ ParserStatus Parser::parseDeclModifierList(DeclAttributes &Attributes,
 ///     '__shared' attribute-list-clause attribute-list
 ///     '__owned' attribute-list-clause attribute-list
 ///     'some' attribute-list-clause attribute-list
+///     'nonisolated(nonsending)' attribute-list-clause attribute-list
 ///   attribute-list-clause:
 ///     '@' attribute
 ///     '@' attribute attribute-list-clause
@@ -5342,12 +5372,49 @@ ParserStatus Parser::ParsedTypeAttributeList::slowParse(Parser &P) {
       continue;
     }
 
+    // nonisolated(nonsending)
+    if (Tok.isContextualKeyword("nonisolated")) {
+      Tok.setKind(tok::contextual_keyword);
+
+      auto kwLoc = P.consumeToken();
+
+      if (CallerIsolatedLoc.isValid()) {
+        P.diagnose(kwLoc, diag::nonisolated_nonsending_repeated)
+            .fixItRemove(SpecifierLoc);
+      }
+
+      // '('
+      if (!P.consumeIfAttributeLParen()) {
+        P.diagnose(Tok, diag::nonisolated_nonsending_expected_lparen);
+        status.setIsParseError();
+        continue;
+      }
+
+      if (!Tok.isContextualKeyword("nonsending")) {
+        P.diagnose(Tok, diag::nonisolated_nonsending_incorrect_modifier);
+        status.setIsParseError();
+        continue;
+      }
+
+      (void)P.consumeToken();
+
+      // ')'
+      if (!P.consumeIf(tok::r_paren)) {
+        P.diagnose(Tok, diag::nonisolated_nonsending_expected_rparen);
+        status.setIsParseError();
+        continue;
+      }
+
+      CallerIsolatedLoc = kwLoc;
+      continue;
+    }
+
     // Perform an extra check for 'sending'. Since it is a specifier, we use
     // the actual parsing logic below.
     if (Tok.isContextualKeyword("sending")) {
       if (!P.Context.LangOpts.hasFeature(Feature::SendingArgsAndResults)) {
         P.diagnose(Tok, diag::requires_experimental_feature, Tok.getRawText(),
-                   false, getFeatureName(Feature::SendingArgsAndResults));
+                   false, Feature::SendingArgsAndResults.getName());
       }
 
       // Only allow for 'sending' to be written once.
@@ -5368,10 +5435,11 @@ ParserStatus Parser::ParsedTypeAttributeList::slowParse(Parser &P) {
     }
 
     if (P.isSILLifetimeDependenceToken()) {
-      if (!P.Context.LangOpts.hasFeature(Feature::LifetimeDependence)) {
+      if (!P.Context.LangOpts.hasFeature(Feature::LifetimeDependence) &&
+          !P.Context.LangOpts.hasFeature(Feature::Lifetimes)) {
         P.diagnose(Tok, diag::requires_experimental_feature,
                    "lifetime dependence specifier", false,
-                   getFeatureName(Feature::LifetimeDependence));
+                   Feature::LifetimeDependence.getName());
       }
       P.consumeToken(); // consume '@'
       auto loc = P.consumeToken(); // consume 'lifetime'
@@ -5457,7 +5525,7 @@ static void diagnoseOperatorFixityAttributes(Parser &P,
   for (auto it = fixityAttrs.begin(); it != fixityAttrs.end(); ++it) {
     if (it != fixityAttrs.begin()) {
       auto *attr = *it;
-      P.diagnose(attr->getLocation(), diag::mutually_exclusive_attrs, attr,
+      P.diagnose(attr->getLocation(), diag::mutually_exclusive_decl_attrs, attr,
                  fixityAttrs.front(), attr->isDeclModifier())
           .fixItRemove(attr->getRange());
       attr->setInvalid();
@@ -5680,12 +5748,14 @@ static bool consumeIfParenthesizedUnowned(Parser &P) {
 }
 
 /// Given a current token of 'nonisolated', check to see if it is followed by an
-/// "(unsafe)" specifier and consumes if it is.
+/// "(unsafe)" or "(nonsending)" specifier and consumes if it is.
 static bool consumeIfParenthesizedNonisolated(Parser &P) {
-  return consumeIfParenthesizedModifier(P, "nonisolated", {"unsafe"});
+  return consumeIfParenthesizedModifier(P, "nonisolated",
+                                        {"unsafe", "nonsending"});
 }
 
 static void skipAttribute(Parser &P) {
+  P.consumeToken(tok::at_sign);
   // Consider unexpected tokens to be incomplete attributes.
 
   // Parse the attribute name, which can be qualified, have
@@ -5702,12 +5772,8 @@ static void skipAttribute(Parser &P) {
   } while (P.consumeIf(tok::period));
 
   // Skip an argument clause after the attribute name.
-  if (P.consumeIf(tok::l_paren)) {
-    while (P.Tok.isNot(tok::r_brace, tok::eof, tok::pound_endif)) {
-      if (P.consumeIf(tok::r_paren)) break;
-      P.skipSingle();
-    }
-  }
+  if (P.isAtAttributeLParen())
+    P.skipSingle();
 }
 
 bool Parser::isStartOfSwiftDecl(bool allowPoundIfAttributes,
@@ -5751,7 +5817,7 @@ bool Parser::isStartOfSwiftDecl(bool allowPoundIfAttributes,
   // in positions like generic argument lists.
   if (Tok.is(tok::at_sign)) {
     BacktrackingScope backtrack(*this);
-    while (consumeIf(tok::at_sign))
+    while (Tok.is(tok::at_sign))
       skipAttribute(*this);
 
     // If this attribute is the last element in the block,
@@ -5843,7 +5909,7 @@ bool Parser::isStartOfSwiftDecl(bool allowPoundIfAttributes,
   // If it might be, we do some more digging.
 
   // If this is 'unowned', check to see if it is valid.
-  if (Tok.getText() == "unowned" && Tok2.is(tok::l_paren)) {
+  if (Tok.getText() == "unowned" && Tok2.isFollowingLParen()) {
     Parser::BacktrackingScope Backtrack(*this);
     if (consumeIfParenthesizedUnowned(*this)) {
       return isStartOfSwiftDecl(/*allowPoundIfAttributes=*/false,
@@ -5852,7 +5918,7 @@ bool Parser::isStartOfSwiftDecl(bool allowPoundIfAttributes,
   }
 
   // If this is 'nonisolated', check to see if it is valid.
-  if (Tok.isContextualKeyword("nonisolated") && Tok2.is(tok::l_paren)) {
+  if (Tok.isContextualKeyword("nonisolated") && Tok2.isFollowingLParen()) {
     BacktrackingScope backtrack(*this);
     if (consumeIfParenthesizedNonisolated(*this)) {
       return isStartOfSwiftDecl(/*allowPoundIfAttributes=*/false,
@@ -5925,6 +5991,17 @@ bool Parser::isStartOfSwiftDecl(bool allowPoundIfAttributes,
     }
   }
 
+  // `using @<attribute>` or `using <identifier>`.
+  if (Tok.isContextualKeyword("using")) {
+    // `using` declarations don't support attributes or modifiers.
+    if (hadAttrsOrModifiers)
+      return false;
+
+    return !Tok2.isAtStartOfLine() &&
+           (Tok2.is(tok::at_sign) || Tok2.is(tok::identifier) ||
+            Tok2.is(tok::code_complete));
+  }
+
   // If the next token is obviously not the start of a decl, bail early.
   if (!isKeywordPossibleDeclStart(Context.LangOpts, Tok2))
     return false;
@@ -6279,6 +6356,17 @@ ParserStatus Parser::parseDecl(bool IsAtStartOfLineOrPreviousHadSemi,
       break;
     }
 
+    // `using @<attribute>` or `using <identifier>`
+    if (Tok.isContextualKeyword("using")) {
+      auto nextToken = peekToken();
+      if (!nextToken.isAtStartOfLine() &&
+          (nextToken.is(tok::at_sign) || nextToken.is(tok::identifier) ||
+           nextToken.is(tok::code_complete))) {
+        DeclResult = parseDeclUsing(Flags, Attributes);
+        break;
+      }
+    }
+
     if (Flags.contains(PD_HasContainerType) &&
         IsAtStartOfLineOrPreviousHadSemi) {
 
@@ -6307,8 +6395,8 @@ ParserStatus Parser::parseDecl(bool IsAtStartOfLineOrPreviousHadSemi,
           DescriptiveKind = DescriptiveDeclKind::StaticProperty;
           break;
         case StaticSpellingKind::KeywordClass:
-          llvm_unreachable("kw_class is only parsed as a modifier if it's "
-                           "followed by a keyword");
+          DescriptiveKind = DescriptiveDeclKind::ClassProperty;
+          break;
         }
 
         diagnose(Tok.getLoc(), diag::expected_keyword_in_decl, "var",
@@ -6336,8 +6424,7 @@ ParserStatus Parser::parseDecl(bool IsAtStartOfLineOrPreviousHadSemi,
             DescriptiveKind = DescriptiveDeclKind::StaticMethod;
             break;
           case StaticSpellingKind::KeywordClass:
-            llvm_unreachable("kw_class is only parsed as a modifier if it's "
-                             "followed by a keyword");
+            DescriptiveKind = DescriptiveDeclKind::ClassMethod;
           }
         }
 
@@ -6626,6 +6713,68 @@ ParserResult<ImportDecl> Parser::parseDeclImport(ParseDeclOptions Flags,
   return DCC.fixupParserResult(ID);
 }
 
+/// Parse an `using` declaration.
+///
+/// \verbatim
+///   decl-using:
+///     'using' (@<attribute> | <modifier>)
+/// \endverbatim
+ParserResult<UsingDecl> Parser::parseDeclUsing(ParseDeclOptions Flags,
+                                               DeclAttributes &Attributes) {
+  assert(Tok.isContextualKeyword("using"));
+  DebuggerContextChange DCC(*this);
+
+  if (!Context.LangOpts.hasFeature(Feature::DefaultIsolationPerFile)) {
+    diagnose(Tok, diag::experimental_using_decl_disabled);
+  }
+
+  SourceLoc UsingLoc = consumeToken();
+
+  if (Tok.is(tok::code_complete)) {
+    if (CodeCompletionCallbacks) {
+      CodeCompletionCallbacks->completeUsingDecl();
+    }
+    return makeParserCodeCompletionStatus();
+  }
+
+  SourceLoc AtLoc;
+  // @<<attribute>>
+  if (Tok.is(tok::at_sign))
+    AtLoc = consumeToken();
+
+  SourceLoc SpecifierLoc;
+  Identifier RawSpecifier;
+
+  if (parseIdentifier(RawSpecifier, SpecifierLoc,
+                      /*diagnoseDollarPrefix=*/false,
+                      diag::expected_identifier_in_decl, "using"))
+    return nullptr;
+
+  std::optional<UsingSpecifier> Specifier =
+      llvm::StringSwitch<std::optional<UsingSpecifier>>(RawSpecifier.str())
+          .Case("MainActor", UsingSpecifier::MainActor)
+          .Case("nonisolated", UsingSpecifier::Nonisolated)
+          .Default(std::nullopt);
+
+  if (!Specifier) {
+    diagnose(SpecifierLoc, diag::using_decl_invalid_specifier);
+    return nullptr;
+  }
+
+  // Complain the `using` not being at top-level only after the specifier
+  // has been consumed, otherwise the specifier is going to be interpreted
+  // as a start of another declaration.
+  if (!CodeCompletionCallbacks && !DCC.movedToTopLevel() &&
+      !(Flags & PD_AllowTopLevel)) {
+    diagnose(UsingLoc, diag::decl_inner_scope);
+    return nullptr;
+  }
+
+  auto *UD = UsingDecl::create(Context, UsingLoc, AtLoc ? AtLoc : SpecifierLoc,
+                               *Specifier, CurDeclContext);
+  return DCC.fixupParserResult(UD);
+}
+
 /// Parse an inheritance clause.
 ///
 /// \verbatim
@@ -6916,9 +7065,8 @@ bool Parser::parseMemberDeclList(SourceLoc &LBLoc, SourceLoc &RBLoc,
     IDC->setMaybeHasDerivativeDeclarations();
 
     if (Flags.contains(PD_StubOnly)) {
-      diagnose(LBLoc, diag::stub_decl_cannot_have_body,
-               IDC->getDecl()->getDescriptiveKind())
-        .fixItRemove({LBLoc, RBLoc});
+      diagnose(LBLoc, diag::stub_decl_cannot_have_body, IDC->getDecl())
+          .fixItRemove({LBLoc, RBLoc});
 
       // Cache the empty result to prevent delayed parsing.
       Context.evaluator.cacheOutput(ParseMembersRequest{IDC},
@@ -7113,6 +7261,12 @@ ParserStatus Parser::parseDeclPoundDiagnostic() {
   bool isError = Tok.is(tok::pound_error);
   consumeToken(isError ? tok::pound_error : tok::pound_warning);
 
+  if (Tok.isAtStartOfLine()) {
+    diagnose(Tok, diag::pound_diagnostic_expected_parens, isError)
+      .fixItInsertAfter(PreviousLoc, "(\"<#message#>\")");
+    return makeParserSuccess();
+  }
+
   SourceLoc lParenLoc = Tok.getLoc();
   bool hadLParen = consumeIf(tok::l_paren);
 
@@ -7209,7 +7363,7 @@ ParserStatus Parser::parseLineDirective(bool isLine) {
   
   unsigned StartLine = 0;
   std::optional<StringRef> Filename;
-  if (!isLine) {
+  if (!isLine && !Tok.isAtStartOfLine()) {
     // #sourceLocation()
     // #sourceLocation(file: "foo", line: 42)
     if (parseToken(tok::l_paren, diag::sourceLocation_expected, "("))
@@ -7689,6 +7843,11 @@ static bool isAllowedWhenParsingLimitedSyntax(AccessorKind kind, bool forSIL) {
 
   case AccessorKind::Init:
     return forSIL;
+
+  // TODO: Add support for borrow/mutate constraints in protocols
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
+    return false;
   }
   llvm_unreachable("bad accessor kind");
 }
@@ -7697,7 +7856,7 @@ struct Parser::ParsedAccessors {
   SourceLoc LBLoc, RBLoc;
   SmallVector<AccessorDecl*, 16> Accessors;
 
-#define ACCESSOR(ID) AccessorDecl *ID = nullptr;
+#define ACCESSOR(ID, KEYWORD) AccessorDecl *ID = nullptr;
 #include "swift/AST/AccessorKinds.def"
 
   void record(Parser &P, AbstractStorageDecl *storage, bool invalid);
@@ -7722,6 +7881,8 @@ struct Parser::ParsedAccessors {
     if (Modify) return Modify;
     if (Modify2) return Modify2;
     if (MutableAddress) return MutableAddress;
+    if (Mutate)
+      return Mutate;
     return nullptr;
   }
 };
@@ -7905,6 +8066,22 @@ bool Parser::parseAccessorAfterIntroducer(
                                           /*underscored*/ false));
   }
 
+  if (requiresFeatureBorrowAndMutateAccessors(Kind) &&
+      !Context.LangOpts.hasFeature(Feature::BorrowAndMutateAccessors)) {
+    diagnose(Tok, diag::accessor_requires_borrow_and_mutate_accessors,
+             getAccessorNameForDiagnostic(Kind, /*article*/ false,
+                                          /*underscored*/ false));
+  }
+
+  if (Kind == AccessorKind::Borrow || Kind == AccessorKind::Mutate) {
+    if (!Flags.contains(PD_InStruct) && !Flags.contains(PD_InEnum) &&
+        !Flags.contains(PD_InExtension)) {
+      diagnose(Tok, diag::accessor_not_supported_in_decl,
+               getAccessorNameForDiagnostic(Kind, /*article*/ true,
+                                            /*underscored*/ false));
+    }
+  }
+
   // There should be no body in the limited syntax; diagnose unexpected
   // accessor implementations.
   if (parsingLimitedSyntax) {
@@ -8096,9 +8273,9 @@ void Parser::parseTopLevelAccessors(
 
   // Prepopulate the field for any accessors that were already parsed parsed accessors
   ParsedAccessors accessors;
-#define ACCESSOR(ID)                                            \
-    if (auto accessor = storage->getAccessor(AccessorKind::ID)) \
-      accessors.ID = accessor;
+#define ACCESSOR(ID, KEYWORD)                                                  \
+  if (auto accessor = storage->getAccessor(AccessorKind::ID))                  \
+    accessors.ID = accessor;
 #include "swift/AST/AccessorKinds.def"
 
   ParserStatus status;
@@ -8299,9 +8476,8 @@ Parser::parseDeclVarGetSet(PatternBindingEntry &entry, ParseDeclOptions Flags,
 
   // Reject accessors when we're parsing stubs only.
   if (Flags.contains(PD_StubOnly) && !accessors.Accessors.empty()) {
-    diagnose(Tok, diag::stub_decl_cannot_have_body,
-             PrimaryVar->getDescriptiveKind())
-      .fixItRemove({ accessors.LBLoc, accessors.RBLoc });
+    diagnose(Tok, diag::stub_decl_cannot_have_body, PrimaryVar)
+        .fixItRemove({accessors.LBLoc, accessors.RBLoc});
     Invalid = true;
   }
 
@@ -8317,13 +8493,13 @@ AccessorDecl *Parser::ParsedAccessors::add(AccessorDecl *accessor) {
   Accessors.push_back(accessor);
 
   switch (accessor->getAccessorKind()) {
-#define ACCESSOR(ID)                      \
-  case AccessorKind::ID:                  \
-    if (ID) {                             \
-      return ID;                          \
-    } else {                              \
-      ID = accessor;                      \
-      return nullptr;                     \
+#define ACCESSOR(ID, KEYWORD)                                                  \
+  case AccessorKind::ID:                                                       \
+    if (ID) {                                                                  \
+      return ID;                                                               \
+    } else {                                                                   \
+      ID = accessor;                                                           \
+      return nullptr;                                                          \
     }
 #include "swift/AST/AccessorKinds.def"
   }
@@ -8354,6 +8530,8 @@ getCorrespondingUnderscoredAccessorKind(AccessorKind kind) {
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
   case AccessorKind::Init:
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
     return std::nullopt;
   }
 }
@@ -8423,16 +8601,21 @@ void Parser::ParsedAccessors::classify(Parser &P, AbstractStorageDecl *storage,
     diagnoseConflictingAccessors(P, Get, Read);
     diagnoseConflictingAccessors(P, Get, Read2);
     diagnoseConflictingAccessors(P, Get, Address);
+    diagnoseConflictingAccessors(P, Get, Borrow);
   } else if (Read) {
     diagnoseConflictingAccessors(P, Read, Read2);
     diagnoseConflictingAccessors(P, Read, Address);
+    diagnoseConflictingAccessors(P, Read, Borrow);
   } else if (Read2) {
     diagnoseConflictingAccessors(P, Read2, Address);
+    diagnoseConflictingAccessors(P, Read2, Borrow);
   } else if (Address) {
+    diagnoseConflictingAccessors(P, Read2, Borrow);
+  } else if (Borrow) {
     // Nothing can go wrong.
 
-  // If there's a writing accessor of any sort, there must also be a
-  // reading accessor.
+    // If there's a writing accessor of any sort, there must also be a
+    // reading accessor.
   } else if (auto mutator = findFirstMutator()) {
     if (!invalid) {
       P.diagnose(mutator->getLoc(),
@@ -8440,7 +8623,8 @@ void Parser::ParsedAccessors::classify(Parser &P, AbstractStorageDecl *storage,
                  // only provided a setter without a getter.
                  (MutableAddress || Modify || Modify2)
                      ? diag::missing_reading_accessor
-                     : diag::missing_getter,
+                 : Mutate ? diag::missing_borrow_accessor
+                          : diag::missing_getter,
                  isa<SubscriptDecl>(storage),
                  getAccessorNameForDiagnostic(mutator, /*article*/ true));
     }
@@ -8454,13 +8638,17 @@ void Parser::ParsedAccessors::classify(Parser &P, AbstractStorageDecl *storage,
   }
 
   // '_modify', 'modify' and 'unsafeMutableAddress' are all mutually exclusive.
-  // 'unsafeMutableAddress' and 'set' are mutually exclusive, but 'set' and
-  // 'modify' can appear together.
+  // 'mutate' and 'set' are mutually exclusive
+  // 'unsafeMutableAddress' and 'set'/'mutate' are mutually exclusive
+  // 'modify' and 'set'/'mutate' can appear together.
   if (Set) {
     diagnoseConflictingAccessors(P, Set, MutableAddress);
+    diagnoseConflictingAccessors(P, Set, Mutate);
   } else if (Modify) {
     diagnoseConflictingAccessors(P, Modify, Modify2);
     diagnoseConflictingAccessors(P, Modify, MutableAddress);
+  } else if (Mutate) {
+    diagnoseConflictingAccessors(P, Mutate, MutableAddress);
   }
 
   if (Init) {
@@ -8778,12 +8966,12 @@ ParserResult<FuncDecl> Parser::parseDeclFunc(SourceLoc StaticLoc,
   SourceLoc NameLoc;
   if (Tok.isAnyOperator() || Tok.isAny(tok::exclaim_postfix, tok::amp_prefix)) {
     // If the name is an operator token that ends in '<' and the following token
-    // is an identifier, split the '<' off as a separate token. This allows
-    // things like 'func ==<T>(x:T, y:T) {}' to parse as '==' with generic type
-    // variable '<T>' as expected.
+    // is an identifier or 'let', split the '<' off as a separate token. This
+    // allows things like 'func ==<T>(x:T, y:T) {}' to parse as '==' with
+    // generic type variable '<T>' as expected.
     auto NameStr = Tok.getText();
     if (NameStr.size() > 1 && NameStr.back() == '<' &&
-        peekToken().is(tok::identifier)) {
+        peekToken().isAny(tok::identifier, tok::kw_let)) {
       NameStr = NameStr.slice(0, NameStr.size() - 1);
     }
     SimpleName = Context.getIdentifier(NameStr);
@@ -9027,9 +9215,8 @@ void Parser::parseAbstractFunctionBody(AbstractFunctionDecl *AFD,
   setIDEInspectionDelayedDeclStateIfNeeded();
 
   if (Flags.contains(PD_StubOnly)) {
-    diagnose(BodyRange.Start, diag::stub_decl_cannot_have_body,
-             AFD->getDescriptiveKind())
-      .fixItRemove(BodyRange);
+    diagnose(BodyRange.Start, diag::stub_decl_cannot_have_body, AFD)
+        .fixItRemove(BodyRange);
     AFD->setBody(nullptr, AbstractFunctionDecl::BodyKind::None);
   }
 }
@@ -9042,7 +9229,7 @@ Parser::parseAbstractFunctionBodyDelayed(AbstractFunctionDecl *AFD) {
   auto bodyRange = AFD->getBodySourceRange();
   auto BeginParserPosition = getParserPosition(bodyRange.Start,
                                                /*previousLoc*/ SourceLoc());
-  auto EndLexerState = L->getStateForEndOfTokenLoc(AFD->getEndLoc());
+  auto EndLexerState = L->getStateForEndOfTokenLoc(bodyRange.End);
 
   // ParserPositionRAII needs a primed parser to restore to.
   if (Tok.is(tok::NUM_TOKENS))
@@ -9140,6 +9327,20 @@ ParserResult<EnumDecl> Parser::parseDeclEnum(ParseDeclOptions Flags,
   return DCC.fixupParserResult(Status, ED);
 }
 
+static bool isValidEnumRawValueLiteral(LiteralExpr *expr) {
+  if (expr == nullptr)
+    return false;
+
+  if (!isa<IntegerLiteralExpr>(expr) &&
+      !isa<FloatLiteralExpr>(expr) &&
+      !isa<StringLiteralExpr>(expr) &&
+      !isa<BooleanLiteralExpr>(expr) &&
+      !isa<NilLiteralExpr>(expr))
+    return false;
+
+  return true;
+}
+
 /// Parse a 'case' of an enum.
 ///
 /// \verbatim
@@ -9257,8 +9458,7 @@ Parser::parseDeclEnumCase(ParseDeclOptions Flags,
       }
       // The raw value must be syntactically a simple literal.
       LiteralRawValueExpr = dyn_cast<LiteralExpr>(RawValueExpr.getPtrOrNull());
-      if (!LiteralRawValueExpr
-          || isa<InterpolatedStringLiteralExpr>(LiteralRawValueExpr)) {
+      if (!isValidEnumRawValueLiteral(LiteralRawValueExpr)) {
         diagnose(RawValueExpr.getPtrOrNull()->getLoc(),
                  diag::nonliteral_enum_case_raw_value);
         LiteralRawValueExpr = nullptr;
@@ -9557,6 +9757,11 @@ ParserStatus Parser::parsePrimaryAssociatedTypeList(
 
     // Parse the comma, if the list continues.
     HasNextParam = consumeIf(tok::comma);
+    
+    // The list ends if we find a trailing comma
+    if (startsWithGreater(Tok)) {
+      break;
+    }
   } while (HasNextParam);
 
   return Result;
@@ -9740,7 +9945,8 @@ Parser::parseDeclSubscript(SourceLoc StaticLoc,
 
     if (ElementTy.isNull()) {
       // Always set an element type.
-      ElementTy = makeParserResult(ElementTy, ErrorTypeRepr::create(Context));
+      ElementTy = makeParserResult(
+          ElementTy, ErrorTypeRepr::create(Context, getTypeErrorLoc()));
     }
   }
 
diff --git a/lib/Parse/ParseExpr.cpp b/lib/Parse/ParseExpr.cpp
index 65bd4a85f94ac..b6e94d0120d4b 100644
--- a/lib/Parse/ParseExpr.cpp
+++ b/lib/Parse/ParseExpr.cpp
@@ -35,6 +35,10 @@
 
 using namespace swift;
 
+bool Token::isEditorPlaceholder() const {
+  return is(tok::identifier) && Identifier::isEditorPlaceholder(getRawText());
+}
+
 /// parseExpr
 ///
 ///   expr:
@@ -421,12 +425,14 @@ ParserResult<Expr> Parser::parseExprSequenceElement(Diag<> message,
 
   if (Tok.isContextualKeyword("unsafe") &&
       !(peekToken().isAtStartOfLine() ||
-        peekToken().isAny(tok::r_paren, tok::r_brace, tok::r_square,
-                          tok::equal, tok::colon, tok::comma, tok::eof) ||
+        peekToken().isAny(tok::r_paren, tok::r_brace, tok::r_square, tok::equal,
+                          tok::colon, tok::comma, tok::eof) ||
         (isExprBasic && peekToken().is(tok::l_brace)) ||
         peekToken().is(tok::period) ||
         (peekToken().isAny(tok::l_paren, tok::l_square) &&
-         peekToken().getRange().getStart() == Tok.getRange().getEnd()))) {
+         peekToken().getRange().getStart() == Tok.getRange().getEnd()) ||
+        peekToken().isBinaryOperatorLike() ||
+        peekToken().isPostfixOperatorLike())) {
     Tok.setKind(tok::contextual_keyword);
     SourceLoc unsafeLoc = consumeToken();
     ParserResult<Expr> sub =
@@ -501,6 +507,9 @@ ParserResult<Expr> Parser::parseExprSequenceElement(Diag<> message,
        peekToken().isContextualPunctuator("~")) &&
       !peekToken().isAtStartOfLine()) {
     ParserResult<TypeRepr> ty = parseType();
+    if (ty.isNull())
+      return nullptr;
+
     auto *typeExpr = new (Context) TypeExpr(ty.get());
     return makeParserResult(typeExpr);
   }
@@ -542,8 +551,9 @@ ParserResult<Expr> Parser::parseExprSequenceElement(Diag<> message,
     consumeToken();
   }
 
-  // Try to parse '@' sign or 'inout' as a attributed typerepr.
-  if (Tok.isAny(tok::at_sign, tok::kw_inout)) {
+  // Try to parse '@' sign, 'inout' or 'nonisolated' as a attributed typerepr.
+  if (Tok.isAny(tok::at_sign, tok::kw_inout) ||
+      Tok.isContextualKeyword("nonisolated")) {
     bool isType = false;
     {
       BacktrackingScope backtrack(*this);
@@ -1497,8 +1507,8 @@ Parser::parseExprPostfixSuffix(ParserResult<Expr> Result, bool isExprBasic,
              SF.getParsingOptions().contains(
                  SourceFile::ParsingFlags::PoundIfAllActive));
       // FIXME: 'PoundIfAllActive' mode should keep all the parsed AST nodes.
-      assert(activeElements[0].is<Expr *>());
-      auto expr = activeElements[0].get<Expr *>();
+      assert(isa<Expr *>(activeElements[0]));
+      auto *expr = cast<Expr *>(activeElements[0]);
       ParserStatus status(ICD);
       auto charRange = Lexer::getCharSourceRangeFromSourceRange(
           SourceMgr, expr->getSourceRange());
@@ -1907,11 +1917,6 @@ ParserResult<Expr> Parser::parseExprPrimary(Diag<> ID, bool isExprBasic) {
   default:
   UnknownCharacter:
     checkForInputIncomplete();
-    // Enable trailing comma in string literal interpolation
-    // Note that 'Tok.is(tok::r_paren)' is not used because the text is ")\"\n" but the kind is actualy 'eof'
-    if (Tok.is(tok::eof) && Tok.getText() == ")") {
-      return nullptr;
-    }
     // FIXME: offer a fixit: 'Self' -> 'self'
     diagnose(Tok, ID);
     return nullptr;
@@ -1972,7 +1977,7 @@ parseStringSegments(SmallVectorImpl<Lexer::StringSegment> &Segments,
         new (Context) UnresolvedDotExpr(InterpolationVarRef,
                                         /*dotloc=*/SourceLoc(),
                                         appendLiteral,
-                                        /*nameloc=*/DeclNameLoc(), 
+                                        /*nameloc=*/DeclNameLoc(TokenLoc),
                                         /*Implicit=*/true);
       auto *ArgList = ArgumentList::forImplicitUnlabeled(Context, {Literal});
       auto AppendLiteralCall =
@@ -2205,7 +2210,7 @@ static bool tryParseArgLabelList(Parser &P, Parser::DeclNameOptions flags,
   // An argument label.
   bool nextIsArgLabel = next.canBeArgumentLabel() || next.is(tok::colon);
   // An editor placeholder.
-  bool nextIsPlaceholder = Identifier::isEditorPlaceholder(next.getText());
+  bool nextIsPlaceholder = next.isEditorPlaceholder();
 
   if (!(nextIsRParen || nextIsArgLabel || nextIsPlaceholder))
     return false;
@@ -2401,7 +2406,7 @@ ParserResult<Expr> Parser::parseExprIdentifier(bool allowKeyword) {
     hasGenericArgumentList = true;
   }
   
-  if (name.getBaseName().isEditorPlaceholder()) {
+  if (IdentTok.isEditorPlaceholder()) {
     return makeParserResult(
         status, parseExprEditorPlaceholder(IdentTok, name.getBaseIdentifier()));
   }
@@ -3300,8 +3305,7 @@ static bool isStartOfLabelledTrailingClosure(Parser &P) {
     return true;
   // Parse editor placeholder as trailing closure so SourceKit can expand it to
   // closure literal.
-  if (P.peekToken().is(tok::identifier) &&
-      Identifier::isEditorPlaceholder(P.peekToken().getText()))
+  if (P.peekToken().isEditorPlaceholder())
     return true;
   // Consider `label: <complete>` that the user is trying to write a closure.
   if (P.peekToken().is(tok::code_complete) && !P.peekToken().isAtStartOfLine())
@@ -3359,8 +3363,8 @@ Parser::parseTrailingClosures(bool isExprBasic, SourceRange calleeRange,
       closure = parseExprClosure();
     } else if (Tok.is(tok::identifier)) {
       // Parse editor placeholder as a closure literal.
-      assert(Identifier::isEditorPlaceholder(Tok.getText()));
-      Identifier name = Context.getIdentifier(Tok.getText());
+      assert(Tok.isEditorPlaceholder());
+      Identifier name = Context.getIdentifier(Tok.getRawText());
       closure = makeParserResult(parseExprEditorPlaceholder(Tok, name));
       consumeToken(tok::identifier);
     } else if (Tok.is(tok::code_complete)) {
@@ -3641,7 +3645,7 @@ Parser::parseExprCollectionElement(std::optional<bool> &isDictionary) {
   } else {
     diagnose(Tok, diag::expected_colon_in_dictionary_literal);
     Value = makeParserResult(makeParserError(),
-                             new (Context) ErrorExpr(SourceRange()));
+                             new (Context) ErrorExpr(PreviousLoc));
   }
 
   // Make a tuple of Key Value pair.
diff --git a/lib/Parse/ParseGeneric.cpp b/lib/Parse/ParseGeneric.cpp
index 265ba7cec0c82..ea0cfa8d9e9f5 100644
--- a/lib/Parse/ParseGeneric.cpp
+++ b/lib/Parse/ParseGeneric.cpp
@@ -351,6 +351,8 @@ ParserStatus Parser::parseGenericWhereClause(
         if (!AllowLayoutConstraints && !isInSILMode()) {
           diagnose(LayoutLoc,
                    diag::layout_constraints_only_inside_specialize_attr);
+          Status.setIsParseError();
+          break;
         } else {
           // Add the layout requirement.
           Requirements.push_back(RequirementRepr::getLayoutConstraint(
diff --git a/lib/Parse/ParseRequests.cpp b/lib/Parse/ParseRequests.cpp
index a5cab7c4162cf..e8672148067bb 100644
--- a/lib/Parse/ParseRequests.cpp
+++ b/lib/Parse/ParseRequests.cpp
@@ -494,7 +494,7 @@ SourceFileParsingResult parseSourceFile(SourceFile &SF) {
 
     case GeneratedSourceInfo::AccessorMacroExpansion: {
       ASTNode astNode = ASTNode::getFromOpaqueValue(generatedInfo->astNode);
-      auto attachedDecl = astNode.get<Decl *>();
+      auto attachedDecl = cast<Decl *>(astNode);
       auto accessorsForStorage = dyn_cast<AbstractStorageDecl>(attachedDecl);
 
       parser.parseTopLevelAccessors(accessorsForStorage, items);
diff --git a/lib/Parse/ParseStmt.cpp b/lib/Parse/ParseStmt.cpp
index 45d0f59112105..35208bdca0393 100644
--- a/lib/Parse/ParseStmt.cpp
+++ b/lib/Parse/ParseStmt.cpp
@@ -230,7 +230,7 @@ static bool isAtStartOfSwitchCase(Parser &parser,
 
     parser.consumeToken(tok::at_sign);
     parser.consumeToken(tok::identifier);
-    if (parser.Tok.is(tok::l_paren))
+    if (parser.isAtAttributeLParen())
       parser.skipSingle();
   }
 
@@ -404,7 +404,10 @@ ParserStatus Parser::parseBraceItems(SmallVectorImpl<ASTNode> &Entries,
       ParserStatus Status = parseLineDirective(false);
       BraceItemsStatus |= Status;
       NeedParseErrorRecovery = Status.isErrorOrHasCompletion();
-    } else if (isStartOfSwiftDecl()) {
+    } else if (isStartOfSwiftDecl() ||
+               // Force parsing '@<identifier>' as a declaration, as there's no
+               // valid expression or statement starting with an attribute.
+               (Tok.is(tok::at_sign) && peekToken().is(tok::identifier))) {
       SmallVector<Decl*, 8> TmpDecls;
       ParserStatus DeclResult =
           parseDecl(IsAtStartOfLineOrPreviousHadSemi,
@@ -462,9 +465,8 @@ ParserStatus Parser::parseBraceItems(SmallVectorImpl<ASTNode> &Entries,
       if (Status.isErrorOrHasCompletion())
         NeedParseErrorRecovery = true;
       else if (!allowTopLevelCode()) {
-        diagnose(StartLoc,
-                 Result.is<Stmt*>() ? diag::illegal_top_level_stmt
-                                    : diag::illegal_top_level_expr);
+        diagnose(StartLoc, isa<Stmt *>(Result) ? diag::illegal_top_level_stmt
+                                               : diag::illegal_top_level_expr);
       }
 
       if (!Result.isNull()) {
@@ -2712,7 +2714,7 @@ ParserResult<CaseStmt> Parser::parseStmtCase(bool IsActive) {
       }
       consumeToken(tok::identifier);
 
-      if (Tok.is(tok::l_paren)) {
+      if (isAtAttributeLParen()) {
         diagnose(Tok, diag::unexpected_lparen_in_attribute, "unknown");
         skipSingle();
       }
@@ -2720,10 +2722,10 @@ ParserResult<CaseStmt> Parser::parseStmtCase(bool IsActive) {
       assert(peekToken().is(tok::identifier) && "isAtStartOfSwitchCase() lied");
 
       consumeToken(tok::at_sign);
-      diagnose(Tok, diag::unknown_attribute, Tok.getText());
+      diagnose(Tok, diag::unknown_attr_name, Tok.getText());
       consumeToken(tok::identifier);
 
-      if (Tok.is(tok::l_paren))
+      if (isAtAttributeLParen())
         skipSingle();
     }
   }
diff --git a/lib/Parse/ParseType.cpp b/lib/Parse/ParseType.cpp
index 414b6056bac9d..1fbf94db39388 100644
--- a/lib/Parse/ParseType.cpp
+++ b/lib/Parse/ParseType.cpp
@@ -59,6 +59,10 @@ Parser::ParsedTypeAttributeList::applyAttributesToType(Parser &p,
     ty = new (p.Context) SendingTypeRepr(ty, SendingLoc);
   }
 
+  if (CallerIsolatedLoc.isValid()) {
+    ty = new (p.Context) CallerIsolatedTypeRepr(ty, CallerIsolatedLoc);
+  }
+
   if (lifetimeEntry) {
     ty = LifetimeDependentTypeRepr::create(p.Context, ty, lifetimeEntry);
   }
@@ -163,9 +167,7 @@ ParserResult<TypeRepr> Parser::parseTypeSimple(
     Diag<> MessageID, ParseTypeReason reason) {
   ParserResult<TypeRepr> ty;
 
-  if (isParameterSpecifier() &&
-      !(!Context.LangOpts.hasFeature(Feature::IsolatedConformances) &&
-        Tok.isContextualKeyword("isolated"))) {
+  if (isParameterSpecifier()) {
     // Type specifier should already be parsed before here. This only happens
     // for construct like 'P1 & inout P2'.
     diagnose(Tok.getLoc(), diag::attr_only_on_parameters, Tok.getRawText());
@@ -740,6 +742,10 @@ ParserStatus Parser::parseGenericArguments(SmallVectorImpl<TypeRepr *> &Args,
       // Parse the comma, if the list continues.
       if (!consumeIf(tok::comma))
         break;
+      
+      // If the comma was a trailing comma, finish parsing the list of types
+      if (startsWithGreater(Tok))
+        break;
     }
   }
 
@@ -1159,7 +1165,7 @@ ParserResult<TypeRepr> Parser::parseTypeTupleBody() {
   SmallVector<TupleTypeReprElement, 8> ElementsR;
 
   ParserStatus Status = parseList(tok::r_paren, LPLoc, RPLoc,
-                                  /*AllowSepAfterLast=*/false,
+                                  /*AllowSepAfterLast=*/true,
                                   diag::expected_rparen_tuple_type_list,
                                   [&] () -> ParserStatus {
     TupleTypeReprElement element;
@@ -1312,17 +1318,15 @@ ParserResult<TypeRepr> Parser::parseTypeTupleBody() {
 }
 
 ParserResult<TypeRepr> Parser::parseTypeInlineArray(SourceLoc lSquare) {
-  ASSERT(Context.LangOpts.hasFeature(Feature::InlineArrayTypeSugar));
-
   ParserStatus status;
 
-  // 'isStartOfInlineArrayTypeBody' means we should at least have a type and 'x'
-  // to start with.
+  // 'isStartOfInlineArrayTypeBody' means we should at least have a type and
+  // 'of' to start with.
   auto count = parseTypeOrValue();
   auto *countTy = count.get();
   status |= count;
 
-  // 'x'
+  // 'of'
   consumeToken(tok::identifier);
 
   // Allow parsing a value for better recovery, Sema will diagnose any
@@ -1603,7 +1607,8 @@ bool Parser::canParseGenericArguments() {
     if (!canParseType())
       return false;
     // Parse the comma, if the list continues.
-  } while (consumeIf(tok::comma));
+    // This could be the trailing comma.
+  } while (consumeIf(tok::comma) && !startsWithGreater(Tok));
 
   if (!startsWithGreater(Tok)) {
     return false;
@@ -1730,6 +1735,36 @@ bool Parser::canParseTypeSimpleOrComposition() {
   return true;
 }
 
+bool Parser::canParseNonisolatedAsTypeModifier() {
+  assert(Tok.isContextualKeyword("nonisolated"));
+
+  BacktrackingScope scope(*this);
+
+  // Consume 'nonisolated'
+  consumeToken();
+
+  // Something like:
+  //
+  // nonisolated
+  //  (42)
+  if (Tok.isAtStartOfLine())
+    return false;
+
+  // Always requires `(nonsending)`, together
+  // we don't want eagerly interpret something
+  // like `nonisolated(0)` as a modifier.
+
+  if (!consumeIf(tok::l_paren))
+    return false;
+
+  if (!Tok.isContextualKeyword("nonsending"))
+    return false;
+
+  consumeToken();
+
+  return consumeIf(tok::r_paren);
+}
+
 bool Parser::canParseTypeScalar() {
   // Accept 'inout' at for better recovery.
   consumeIf(tok::kw_inout);
@@ -1737,6 +1772,16 @@ bool Parser::canParseTypeScalar() {
   if (Tok.isContextualKeyword("sending"))
     consumeToken();
 
+  if (Tok.isContextualKeyword("nonisolated")) {
+    if (!canParseNonisolatedAsTypeModifier())
+      return false;
+
+    // consume 'nonisolated'
+    consumeToken();
+    // skip '(nonsending)'
+    skipSingle();
+  }
+
   if (!canParseTypeSimpleOrComposition())
     return false;
 
@@ -1777,19 +1822,16 @@ bool Parser::canParseType() {
 }
 
 bool Parser::canParseStartOfInlineArrayType() {
-  if (!Context.LangOpts.hasFeature(Feature::InlineArrayTypeSugar))
-    return false;
-
-  // We must have at least '[<type> x', which cannot be any other kind of
+  // We must have at least '[<type> of', which cannot be any other kind of
   // expression or type. We specifically look for any type, not just integers
-  // for better recovery in e.g cases where the user writes '[Int x 2]'. We
-  // only do type-scalar since variadics would be ambiguous e.g 'Int...x'.
+  // for better recovery in e.g cases where the user writes '[Int of 2]'. We
+  // only do type-scalar since variadics would be ambiguous e.g 'Int...of'.
   if (!canParseTypeScalar())
     return false;
 
   // For now we don't allow multi-line since that would require
   // disambiguation.
-  if (Tok.isAtStartOfLine() || !Tok.isContextualKeyword("x"))
+  if (Tok.isAtStartOfLine() || !Tok.isContextualKeyword("of"))
     return false;
 
   consumeToken();
@@ -1797,9 +1839,6 @@ bool Parser::canParseStartOfInlineArrayType() {
 }
 
 bool Parser::isStartOfInlineArrayTypeBody() {
-  if (!Context.LangOpts.hasFeature(Feature::InlineArrayTypeSugar))
-    return false;
-
   BacktrackingScope backtrack(*this);
   return canParseStartOfInlineArrayType();
 }
@@ -1809,7 +1848,7 @@ bool Parser::canParseCollectionType() {
     return false;
 
   // Check to see if we have an InlineArray sugar type.
-  if (Context.LangOpts.hasFeature(Feature::InlineArrayTypeSugar)) {
+  {
     CancellableBacktrackingScope backtrack(*this);
     if (canParseStartOfInlineArrayType()) {
       backtrack.cancelBacktrack();
@@ -1928,7 +1967,7 @@ bool Parser::canParseTypeTupleBody() {
           skipSingle();
         }
       }
-    } while (consumeIf(tok::comma));
+    } while (consumeIf(tok::comma) && Tok.isNot(tok::r_paren));
   }
   
   return consumeIf(tok::r_paren);
diff --git a/lib/Parse/Parser.cpp b/lib/Parse/Parser.cpp
index a307969adfd5b..11bb865563b98 100644
--- a/lib/Parse/Parser.cpp
+++ b/lib/Parse/Parser.cpp
@@ -116,7 +116,7 @@ bool IDEInspectionSecondPassRequest::evaluate(
     IDEInspectionCallbacksFactory *Factory) const {
   // If we didn't find the code completion token, bail.
   auto *parserState = SF->getDelayedParserState();
-  if (!parserState->hasIDEInspectionDelayedDeclState())
+  if (!parserState || !parserState->hasIDEInspectionDelayedDeclState())
     return true;
 
   // Decrement the closure discriminator index by one so a top-level closure
@@ -162,6 +162,7 @@ void Parser::performIDEInspectionSecondPassImpl(
   // Clear any ASTScopes that were expanded.
   SF.clearScope();
 
+  // FIXME: We shouldn't be mutating the AST after-the-fact like this.
   switch (info.Kind) {
   case IDEInspectionDelayedDeclKind::TopLevelCodeDecl: {
     // Re-enter the top-level code decl context.
@@ -611,14 +612,49 @@ SourceLoc Parser::consumeAttributeLParen() {
   return consumeToken(tok::l_paren);
 }
 
-bool Parser::consumeIfAttributeLParen() {
-  if (!Tok.isFollowingLParen()) {
+bool Parser::consumeIfAttributeLParen(bool isCustomAttr) {
+  if (!isAtAttributeLParen(isCustomAttr))
     return false;
-  }
-  consumeAttributeLParen();
+  (void)consumeAttributeLParen();
   return true;
 }
 
+bool Parser::isAtAttributeLParen(bool isCustomAttr) {
+  if (!Tok.isFollowingLParen())
+    return false;
+
+  if (Context.isSwiftVersionAtLeast(6)) {
+    // No-space '(' are always arguments.
+    if (getEndOfPreviousLoc() == Tok.getLoc())
+      return true;
+
+    // Otherwise it's an error, but for recovery, parse it as an argument list
+    // if it's obvious.
+    BacktrackingScope backtrack(*this);
+    skipSingle();
+    return Tok.is(tok::at_sign) || isStartOfSwiftDecl();
+  } else {
+    // In <=5, builtin attributes only checks 'isFollowingLParen()'.
+    if (!isCustomAttr)
+      return true;
+
+    BacktrackingScope backtrack(*this);
+    if (skipSingle().hasCodeCompletion())
+      return true;
+
+    // If we have any keyword, identifier, or token that follows a function
+    // type's parameter list, this is a parameter list and not an attribute.
+    // Alternatively, we might have a token that illustrates we're not going to
+    // get anything following the attribute, which means the parentheses
+    // describe what follows the attribute.
+    return (!Tok.isAny(tok::arrow, tok::kw_throw, tok::kw_throws,
+                       tok::kw_rethrows, tok::r_paren, tok::r_brace,
+                       tok::r_square, tok::r_angle) &&
+            !Tok.isContextualKeyword("async") &&
+            !Tok.isContextualKeyword("reasync"));
+  }
+}
+
 SourceLoc Parser::consumeStartingCharacterOfCurrentToken(tok Kind, size_t Len) {
   // Consumes prefix of token and returns its location.
   // (like '?', '<', '>' or '!' immediately followed by '<') 
@@ -1057,11 +1093,18 @@ Parser::parseListItem(ParserStatus &Status, tok RightK, SourceLoc LeftLoc,
       return ParseListItemResult::Finished;
   }
   if (consumeIf(tok::comma)) {
-    if (Tok.isNot(RightK))
+    if (Tok.isNot(RightK) && !tokIsStringInterpolationEOF(Tok, RightK))
       return ParseListItemResult::Continue;
     if (!AllowSepAfterLast) {
       diagnose(Tok, diag::unexpected_separator, ",").fixItRemove(PreviousLoc);
     }
+    
+    // Enable trailing comma in string literal interpolation
+    if (tokIsStringInterpolationEOF(Tok, RightK)) {
+      RightLoc = Tok.getLoc();
+      return ParseListItemResult::FinishedInStringInterpolation;
+    }
+    
     return ParseListItemResult::Finished;
   }
   // If we're in a comma-separated list, the next token is at the
diff --git a/lib/PrintAsClang/ClangSyntaxPrinter.cpp b/lib/PrintAsClang/ClangSyntaxPrinter.cpp
index 7c2cefbcf8f59..21078f534907e 100644
--- a/lib/PrintAsClang/ClangSyntaxPrinter.cpp
+++ b/lib/PrintAsClang/ClangSyntaxPrinter.cpp
@@ -11,18 +11,21 @@
 //===----------------------------------------------------------------------===//
 
 #include "ClangSyntaxPrinter.h"
+#include "DeclAndTypePrinter.h"
 #include "PrimitiveTypeMapping.h"
 #include "swift/ABI/MetadataValues.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/SwiftNameTranslation.h"
+#include "swift/AST/Type.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/Basic/Assertions.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/NestedNameSpecifier.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Casting.h"
 
 using namespace swift;
@@ -98,6 +101,12 @@ bool ClangSyntaxPrinter::printNominalTypeOutsideMemberDeclInnerStaticAssert(
 }
 
 void ClangSyntaxPrinter::printClangTypeReference(const clang::Decl *typeDecl) {
+  StringRef osObjectName = DeclAndTypePrinter::maybeGetOSObjectBaseName(
+      dyn_cast<clang::NamedDecl>(cast<clang::NamedDecl>(typeDecl)));
+  if (!osObjectName.empty()) {
+    os << osObjectName << "_t";
+    return;
+  }
   if (cast<clang::NamedDecl>(typeDecl)->getDeclName().isEmpty() &&
       isa<clang::TagDecl>(typeDecl)) {
     if (auto *tnd =
@@ -127,22 +136,28 @@ void ClangSyntaxPrinter::printClangTypeReference(const clang::Decl *typeDecl) {
   }
 }
 
-bool ClangSyntaxPrinter::printNestedTypeNamespaceQualifiers(
-    const ValueDecl *D) const {
+bool ClangSyntaxPrinter::printNestedTypeNamespaceQualifiers(const ValueDecl *D,
+                                                            bool forC) const {
   bool first = true;
-  while (auto parent = dyn_cast_or_null<NominalTypeDecl>(
-             D->getDeclContext()->getAsDecl())) {
+  while (auto parent = D->getDeclContext()->getAsDecl()) {
+    const auto *parentNTD = dyn_cast<NominalTypeDecl>(parent);
+    if (!parentNTD)
+      if (const auto *ED = dyn_cast<ExtensionDecl>(parent))
+        parentNTD = ED->getExtendedNominal();
+    if (!parentNTD)
+      continue;
     // C++ namespaces are imported as enums.
-    if (parent->hasClangNode() &&
-        isa<clang::NamespaceDecl>(parent->getClangNode().getAsDecl()))
+    if (parentNTD->hasClangNode() &&
+        isa<clang::NamespaceDecl>(parentNTD->getClangNode().getAsDecl()))
       break;
     if (!first)
-      os << "::";
+      os << (forC ? "_" : "::");
     first = false;
-    os << "__";
-    printBaseName(parent);
+    if (!forC)
+      os << "__";
+    printBaseName(parentNTD);
     os << "Nested";
-    D = parent;
+    D = parentNTD;
   }
   return first;
 }
@@ -205,7 +220,9 @@ void ClangSyntaxPrinter::printNamespace(
 void ClangSyntaxPrinter::printParentNamespaceForNestedTypes(
     const ValueDecl *D, llvm::function_ref<void(raw_ostream &OS)> bodyPrinter,
     NamespaceTrivia trivia) const {
-  if (!isa_and_nonnull<NominalTypeDecl>(D->getDeclContext()->getAsDecl())) {
+  if ((!isa_and_nonnull<NominalTypeDecl>(D->getDeclContext()->getAsDecl()) &&
+       !isa_and_nonnull<ExtensionDecl>(D->getDeclContext()->getAsDecl())) ||
+      importer::isClangNamespace(D->getDeclContext())) {
     bodyPrinter(os);
     return;
   }
diff --git a/lib/PrintAsClang/ClangSyntaxPrinter.h b/lib/PrintAsClang/ClangSyntaxPrinter.h
index 106e2cf07253f..331d666a066eb 100644
--- a/lib/PrintAsClang/ClangSyntaxPrinter.h
+++ b/lib/PrintAsClang/ClangSyntaxPrinter.h
@@ -96,7 +96,8 @@ class ClangSyntaxPrinter {
       const NominalTypeDecl *typeDecl);
 
   // Returns true when no qualifiers were printed.
-  bool printNestedTypeNamespaceQualifiers(const ValueDecl *D) const;
+  bool printNestedTypeNamespaceQualifiers(const ValueDecl *D,
+                                          bool forC = false) const;
 
   /// Print out the C++ class access qualifier for the given Swift  type
   /// declaration.
diff --git a/lib/PrintAsClang/DeclAndTypePrinter.cpp b/lib/PrintAsClang/DeclAndTypePrinter.cpp
index e396d698454c8..ea84364f60407 100644
--- a/lib/PrintAsClang/DeclAndTypePrinter.cpp
+++ b/lib/PrintAsClang/DeclAndTypePrinter.cpp
@@ -22,6 +22,7 @@
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/ASTVisitor.h"
+#include "swift/AST/Attr.h"
 #include "swift/AST/ClangSwiftTypeCorrespondence.h"
 #include "swift/AST/Comment.h"
 #include "swift/AST/ConformanceLookup.h"
@@ -253,7 +254,6 @@ class DeclAndTypePrinter::Implementation
   /// Prints the members of a class, extension, or protocol.
   template <bool AllowDelayed = false, typename R>
   void printMembers(R &&members) {
-    CxxEmissionScopeRAII cxxScopeRAII(owningPrinter);
     // Using statements for nested types.
     if (outputLang == OutputLanguageMode::Cxx) {
       for (const Decl *member : members) {
@@ -373,7 +373,12 @@ class DeclAndTypePrinter::Implementation
     if (outputLang == OutputLanguageMode::Cxx) {
       // FIXME: Non objc class.
       ClangClassTypePrinter(os).printClassTypeDecl(
-          CD, [&]() { printMembers(CD->getAllMembers()); }, owningPrinter);
+          CD,
+          [&]() {
+            CxxEmissionScopeRAII cxxScopeRAII(owningPrinter);
+            printMembers(CD->getAllMembers());
+          },
+          owningPrinter);
       recordEmittedDeclInCurrentCxxLexicalScope(CD);
       return;
     }
@@ -426,6 +431,7 @@ class DeclAndTypePrinter::Implementation
     printer.printValueTypeDecl(
         SD, /*bodyPrinter=*/
         [&]() {
+          CxxEmissionScopeRAII cxxScopeRAII(owningPrinter);
           printMembers(SD->getAllMembers());
           for (const auto *ed :
                owningPrinter.interopContext.getExtensionsForNominalType(SD)) {
@@ -922,6 +928,7 @@ class DeclAndTypePrinter::Implementation
           os << "  }\n"; // operator cases()'s closing bracket
           os << "\n";
 
+          CxxEmissionScopeRAII cxxScopeRAII(owningPrinter);
           printMembers(ED->getAllMembers());
 
           for (const auto *ext :
@@ -1244,7 +1251,8 @@ class DeclAndTypePrinter::Implementation
     // Constructors and methods returning DynamicSelf return
     // instancetype.
     if (isa<ConstructorDecl>(AFD) ||
-        (isa<FuncDecl>(AFD) && cast<FuncDecl>(AFD)->hasDynamicSelfResult() &&
+        (isa<FuncDecl>(AFD) &&
+         cast<FuncDecl>(AFD)->getResultInterfaceType()->hasDynamicSelfType() &&
          !AFD->hasAsync())) {
       if (errorConvention && errorConvention->stripsResultOptionality()) {
         printNullability(OTK_Optional, NullabilityPrintKind::ContextSensitive);
@@ -1702,9 +1710,24 @@ class DeclAndTypePrinter::Implementation
     };
 
     for (auto AvAttr : D->getSemanticAvailableAttrs()) {
-      if (AvAttr.getPlatform() == PlatformKind::none) {
-        if (AvAttr.isUnconditionallyUnavailable() &&
-            !AvAttr.getDomain().isSwiftLanguage()) {
+      auto domain = AvAttr.getDomain();
+      if (auto domainDecl = domain.getDecl()) {
+        // If the domain is defined in a Clang module then the attr can be
+        // printed.
+        if (domainDecl->hasClangNode()) {
+          // Versioned custom domains aren't supported yet.
+          ASSERT(!domain.isVersioned());
+
+          maybePrintLeadingSpace();
+          os << "SWIFT_AVAILABILITY_DOMAIN("
+             << domain.getNameForAttributePrinting() << ","
+             << (AvAttr.isUnconditionallyUnavailable() ? "1" : "0") << ")";
+        }
+        continue;
+      }
+
+      if (domain.isUniversal()) {
+        if (AvAttr.isUnconditionallyUnavailable()) {
           // Availability for *
           if (!AvAttr.getRename().empty() && isa<ValueDecl>(D)) {
             // rename
@@ -1749,6 +1772,9 @@ class DeclAndTypePrinter::Implementation
       }
 
       // Availability for a specific platform
+      if (!domain.isPlatform())
+        continue;
+
       if (!AvAttr.getIntroduced().has_value() &&
           !AvAttr.getDeprecated().has_value() &&
           !AvAttr.getObsoleted().has_value() &&
@@ -1795,6 +1821,9 @@ class DeclAndTypePrinter::Implementation
       case PlatformKind::visionOSApplicationExtension:
         plat = "visionos_app_extension";
         break;
+      case PlatformKind::FreeBSD:
+        plat = "freebsd";
+        break;
       case PlatformKind::OpenBSD:
         plat = "openbsd";
         break;
@@ -2207,8 +2236,7 @@ class DeclAndTypePrinter::Implementation
       return nullptr;
 
     // Dig out the Objective-C type.
-    Type objcType = conformance.getTypeWitnessByName(
-        declaredType, ctx.Id_ObjectiveCType);
+    Type objcType = conformance.getTypeWitnessByName(ctx.Id_ObjectiveCType);
 
     // Dig out the Objective-C class.
     return objcType->getClassOrBoundGenericClass();
@@ -2290,6 +2318,14 @@ class DeclAndTypePrinter::Implementation
     return false;
   }
 
+  std::optional<PrimitiveTypeMapping::ClangTypeInfo>
+  getKnownType(const TypeDecl *typeDecl) {
+    if (outputLang == OutputLanguageMode::C)
+      return owningPrinter.typeMapping.getKnownCTypeInfo(typeDecl);
+
+    return owningPrinter.typeMapping.getKnownObjCTypeInfo(typeDecl);
+  }
+
   /// If \p typeDecl is one of the standard library types used to map in Clang
   /// primitives and basic types, print out the appropriate spelling and
   /// return true.
@@ -2298,8 +2334,7 @@ class DeclAndTypePrinter::Implementation
   /// for interfacing with C and Objective-C.
   bool printIfKnownSimpleType(const TypeDecl *typeDecl,
                               std::optional<OptionalTypeKind> optionalKind) {
-    auto knownTypeInfo =
-        owningPrinter.typeMapping.getKnownObjCTypeInfo(typeDecl);
+    auto knownTypeInfo = getKnownType(typeDecl);
     if (!knownTypeInfo)
       return false;
     os << knownTypeInfo->name;
@@ -2379,8 +2414,15 @@ class DeclAndTypePrinter::Implementation
   }
 
   void maybePrintTagKeyword(const TypeDecl *NTD) {
-    if (isa<EnumDecl>(NTD) && !NTD->hasClangNode()) {
-      os << "enum ";
+    auto *ED = dyn_cast<EnumDecl>(NTD);
+    if (ED && !NTD->hasClangNode()) {
+      if (ED->isCDeclEnum()) {
+        // We should be able to use the tag macro for all printed enums but
+        // for now restrict it to @c to guard it behind the feature flag.
+        os << "SWIFT_ENUM_TAG ";
+      } else {
+        os << "enum ";
+      }
       return;
     }
 
@@ -2935,6 +2977,17 @@ static bool excludeForObjCImplementation(const ValueDecl *VD) {
   return false;
 }
 
+bool swift::hasExposeNotCxxAttr(const ValueDecl *VD) {
+  for (const auto *attr : VD->getAttrs().getAttributes<ExposeAttr>())
+    if (attr->getExposureKind() == ExposureKind::NotCxx)
+      return true;
+  if (const auto *NMT = dyn_cast<NominalTypeDecl>(VD->getDeclContext()))
+    return hasExposeNotCxxAttr(NMT);
+  if (const auto *ED = dyn_cast<ExtensionDecl>(VD->getDeclContext()))
+    return hasExposeNotCxxAttr(ED->getExtendedNominal());
+  return false;
+}
+
 static bool isExposedToThisModule(const ModuleDecl &M, const ValueDecl *VD,
                                   const llvm::StringSet<> &exposedModules) {
   if (VD->hasClangNode())
@@ -2986,6 +3039,9 @@ bool DeclAndTypePrinter::shouldInclude(const ValueDecl *VD) {
   if (requiresExposedAttribute && !hasExposeAttr(VD))
     return false;
 
+  if (hasExposeNotCxxAttr(VD))
+    return false;
+
   if (!isVisible(VD))
     return false;
 
@@ -3000,6 +3056,30 @@ bool DeclAndTypePrinter::shouldInclude(const ValueDecl *VD) {
       return false;
   }
 
+  // In C output mode print only the C variant `@c` (no `@_cdecl`),
+  // while in other modes print only `@_cdecl`.
+  std::optional<ForeignLanguage> cdeclKind = std::nullopt;
+  if (auto *FD = dyn_cast<AbstractFunctionDecl>(VD))
+    cdeclKind = FD->getCDeclKind();
+  if (cdeclKind &&
+      (*cdeclKind == ForeignLanguage::C) !=
+       (outputLang == OutputLanguageMode::C))
+    return false;
+
+  // C output mode only prints @c functions and enums.
+  if (outputLang == OutputLanguageMode::C &&
+      !cdeclKind && !isa<EnumDecl>(VD)) {
+    return false;
+  }
+
+  // The C mode prints @c enums and reject other enums,
+  // while other modes accept other enums and reject @c ones.
+  if (isa<EnumDecl>(VD) &&
+      VD->getAttrs().hasAttribute<CDeclAttr>() !=
+        (outputLang == OutputLanguageMode::C)) {
+    return false;
+  }
+
   if (VD->getAttrs().hasAttribute<ImplementationOnlyAttr>())
     return false;
 
@@ -3069,6 +3149,8 @@ const TypeDecl *DeclAndTypePrinter::getObjCTypeDecl(const TypeDecl* TD) {
 
 StringRef
 DeclAndTypePrinter::maybeGetOSObjectBaseName(const clang::NamedDecl *decl) {
+  if (!decl)
+    return StringRef();
   StringRef name = decl->getName();
   if (!name.consume_front("OS_"))
     return StringRef();
diff --git a/lib/PrintAsClang/DeclAndTypePrinter.h b/lib/PrintAsClang/DeclAndTypePrinter.h
index 55c7a57344a41..a824e82b6d9db 100644
--- a/lib/PrintAsClang/DeclAndTypePrinter.h
+++ b/lib/PrintAsClang/DeclAndTypePrinter.h
@@ -160,6 +160,8 @@ class DeclAndTypePrinter {
 
 bool isStringNestedType(const ValueDecl *VD, StringRef Typename);
 
+bool hasExposeNotCxxAttr(const ValueDecl *VD);
+
 } // end namespace swift
 
 #endif
diff --git a/lib/PrintAsClang/ModuleContentsWriter.cpp b/lib/PrintAsClang/ModuleContentsWriter.cpp
index ef164898bbaed..f8b14a94eabf1 100644
--- a/lib/PrintAsClang/ModuleContentsWriter.cpp
+++ b/lib/PrintAsClang/ModuleContentsWriter.cpp
@@ -29,6 +29,7 @@
 #include "swift/AST/SwiftNameTranslation.h"
 #include "swift/AST/TypeDeclFinder.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/Basic/Feature.h"
 #include "swift/Basic/SourceManager.h"
 #include "swift/ClangImporter/ClangImporter.h"
 #include "swift/SIL/SILInstruction.h"
@@ -457,6 +458,14 @@ class ModuleWriter {
       }
     }
 
+    if (isa<EnumDecl>(D) && !D->hasClangNode() &&
+        outputLangMode != OutputLanguageMode::Cxx) {
+      // We don't want to add an import for a @c or @objc enum declared
+      // in Swift. We either do nothing for special enums like Optional as
+      // done in the prologue here, or we forward declare them.
+      return false;
+    }
+
     imports.insert(otherModule);
     return true;
   }
@@ -530,12 +539,19 @@ class ModuleWriter {
   }
 
   void forwardDeclare(const EnumDecl *ED) {
-    assert(ED->isObjC() || ED->hasClangNode());
+    assert(ED->isCCompatibleEnum() || ED->hasClangNode());
     
     forwardDeclare(ED, [&]{
-      os << "enum " << getNameForObjC(ED) << " : ";
-      printer.print(ED->getRawType());
-      os << ";\n";
+      if (ED->getASTContext().LangOpts.hasFeature(Feature::CDecl)) {
+        // Forward declare in a way to be compatible with older C standards.
+        os << "typedef SWIFT_ENUM_FWD_DECL(";
+        printer.print(ED->getRawType());
+        os << ", " << getNameForObjC(ED) << ")\n";
+      } else {
+        os << "enum " << getNameForObjC(ED) << " : ";
+        printer.print(ED->getRawType());
+        os << ";\n";
+      }
     });
   }
 
@@ -580,7 +596,8 @@ class ModuleWriter {
         else if (isa<StructDecl>(TD) && NTD->hasClangNode())
           emitReferencedClangTypeMetadata(NTD);
         else if (const auto *cd = dyn_cast<ClassDecl>(TD))
-          if (cd->isObjC() || cd->isForeignReferenceType())
+          if ((cd->isObjC() && cd->getClangDecl()) ||
+              cd->isForeignReferenceType())
             emitReferencedClangTypeMetadata(NTD);
       } else if (auto TAD = dyn_cast<TypeAliasDecl>(TD)) {
         if (TAD->hasClangNode())
@@ -604,6 +621,7 @@ class ModuleWriter {
     } else if (addImport(TD)) {
       return;
     } else if (auto ED = dyn_cast<EnumDecl>(TD)) {
+      // Treat this after addImport to filter out special enums from the stdlib.
       forwardDeclare(ED);
     } else if (isa<GenericTypeParamDecl>(TD)) {
       llvm_unreachable("should not see generic parameters here");
@@ -666,6 +684,8 @@ class ModuleWriter {
         continue;
       }
 
+      addImportsForReferencedAvailabilityDomains(member);
+
       bool needsToBeIndividuallyDelayed = false;
       ReferencedTypeFinder::walk(VD->getInterfaceType(),
                                  [&](ReferencedTypeFinder &finder,
@@ -727,6 +747,15 @@ class ModuleWriter {
     return !hadAnyDelayedMembers;
   }
 
+  void addImportsForReferencedAvailabilityDomains(const Decl *D) {
+    for (auto attr : D->getSemanticAvailableAttrs()) {
+      if (auto *domainDecl = attr.getDomain().getDecl()) {
+        if (domainDecl->hasClangNode())
+          addImport(domainDecl);
+      }
+    }
+  }
+
   bool writeClass(const ClassDecl *CD) {
     if (addImport(CD))
       return true;
@@ -750,11 +779,16 @@ class ModuleWriter {
       return false;
 
     (void)forwardDeclareMemberTypes(CD->getAllMembers(), CD);
+    for (const auto *ed :
+         printer.getInteropContext().getExtensionsForNominalType(CD)) {
+      (void)forwardDeclareMemberTypes(ed->getAllMembers(), CD);
+    }
     auto [it, inserted] =
         seenTypes.try_emplace(CD, EmissionState::NotYetDefined, false);
     if (outputLangMode == OutputLanguageMode::Cxx &&
         (inserted || !it->second.second))
       ClangValueTypePrinter::forwardDeclType(os, CD, printer);
+    addImportsForReferencedAvailabilityDomains(CD);
     it->second = {EmissionState::Defined, true};
     printer.print(CD);
     return true;
@@ -773,6 +807,7 @@ class ModuleWriter {
                                      TD);
           forwardDeclareType(TD);
         });
+    addImportsForReferencedAvailabilityDomains(FD);
 
     printer.print(FD);
     return true;
@@ -789,6 +824,7 @@ class ModuleWriter {
       }
       forwardDeclareCxxValueTypeIfNeeded(SD);
     }
+    addImportsForReferencedAvailabilityDomains(SD);
     printer.print(SD);
     return true;
   }
@@ -815,6 +851,8 @@ class ModuleWriter {
     if (!forwardDeclareMemberTypes(PD->getAllMembers(), PD))
       return false;
 
+    addImportsForReferencedAvailabilityDomains(PD);
+
     seenTypes[PD] = { EmissionState::Defined, true };
     printer.print(PD);
     return true;
@@ -841,6 +879,8 @@ class ModuleWriter {
     if (!forwardDeclareMemberTypes(ED->getAllMembers(), ED))
       return false;
 
+    addImportsForReferencedAvailabilityDomains(ED);
+
     printer.print(ED);
     return true;
   }
@@ -851,12 +891,18 @@ class ModuleWriter {
 
     if (outputLangMode == OutputLanguageMode::Cxx) {
       forwardDeclareMemberTypes(ED->getAllMembers(), ED);
+      for (const auto *ed :
+           printer.getInteropContext().getExtensionsForNominalType(ED)) {
+        (void)forwardDeclareMemberTypes(ed->getAllMembers(), ED);
+      }
       forwardDeclareCxxValueTypeIfNeeded(ED);
     }
 
     if (seenTypes[ED].first == EmissionState::Defined)
       return true;
-    
+
+    addImportsForReferencedAvailabilityDomains(ED);
+
     seenTypes[ED] = {EmissionState::Defined, true};
     printer.print(ED);
 
@@ -864,7 +910,7 @@ class ModuleWriter {
 
     SmallVector<ProtocolConformance *, 1> conformances;
     auto errorTypeProto = ctx.getProtocol(KnownProtocolKind::Error);
-    if (outputLangMode != OutputLanguageMode::Cxx
+    if (outputLangMode == OutputLanguageMode::ObjC
         && ED->lookupConformance(errorTypeProto, conformances)) {
       bool hasDomainCase = std::any_of(ED->getAllElements().begin(),
                                        ED->getAllElements().end(),
@@ -1017,7 +1063,8 @@ class ModuleWriter {
     // library. Also skip structs from the standard library, they can cause
     // ambiguities because of the arithmetic types that conflict with types we
     // already have in `swift::` namespace. Also skip `Error` protocol from
-    // stdlib, we have experimental support for it.
+    // stdlib, we have experimental support for it. Also skip explicitly exluded
+    // declarations.
     removedVDList.erase(
         llvm::remove_if(
             removedVDList,
@@ -1027,7 +1074,8 @@ class ModuleWriter {
                       vd->getBaseIdentifier().hasUnderscoredNaming()) ||
                      (vd->isStdlibDecl() && isa<StructDecl>(vd)) ||
                      (vd->isStdlibDecl() &&
-                      vd->getASTContext().getErrorDecl() == vd);
+                      vd->getASTContext().getErrorDecl() == vd) ||
+                     swift::hasExposeNotCxxAttr(vd);
             }),
         removedVDList.end());
     // Sort the unavaiable decls by their name and kind.
@@ -1118,6 +1166,17 @@ void swift::printModuleContentsAsObjC(
       .write();
 }
 
+void swift::printModuleContentsAsC(
+    raw_ostream &os, llvm::SmallPtrSetImpl<ImportModuleTy> &imports,
+    ModuleDecl &M, SwiftToClangInteropContext &interopContext) {
+  llvm::raw_null_ostream prologueOS;
+  llvm::StringSet<> exposedModules;
+  ModuleWriter(os, prologueOS, imports, M, interopContext, getRequiredAccess(M),
+               /*requiresExposedAttribute=*/false, exposedModules,
+               OutputLanguageMode::C)
+      .write();
+}
+
 EmittedClangHeaderDependencyInfo swift::printModuleContentsAsCxx(
     raw_ostream &os, ModuleDecl &M, SwiftToClangInteropContext &interopContext,
     bool requiresExposedAttribute, llvm::StringSet<> &exposedModules) {
@@ -1126,13 +1185,14 @@ EmittedClangHeaderDependencyInfo swift::printModuleContentsAsCxx(
   std::string modulePrologueBuf;
   llvm::raw_string_ostream prologueOS{modulePrologueBuf};
   EmittedClangHeaderDependencyInfo info;
+  auto &context = M.getASTContext();
 
   // Define the `SWIFT_SYMBOL` macro.
   os << "#ifdef SWIFT_SYMBOL\n";
   os << "#undef SWIFT_SYMBOL\n";
   os << "#endif\n";
   os << "#define SWIFT_SYMBOL(usrValue) SWIFT_SYMBOL_MODULE_USR(\"";
-  ClangSyntaxPrinter(M.getASTContext(), os).printBaseName(&M);
+  ClangSyntaxPrinter(context, os).printBaseName(&M);
   os << "\", usrValue)\n";
 
   // FIXME: Use getRequiredAccess once @expose is supported.
@@ -1147,9 +1207,11 @@ EmittedClangHeaderDependencyInfo swift::printModuleContentsAsCxx(
     os << "#include <string>\n";
     os << "#endif\n";
     os << "#include <new>\n";
+    if (context.LangOpts.hasFeature(Feature::Embedded))
+      os << "#define __EmbeddedSwift__\n";
     // Embed an overlay for the standard library.
-    ClangSyntaxPrinter(M.getASTContext(), moduleOS).printIncludeForShimHeader(
-        "_SwiftStdlibCxxOverlay.h");
+    ClangSyntaxPrinter(context, moduleOS)
+        .printIncludeForShimHeader("_SwiftStdlibCxxOverlay.h");
     // Ignore typos in Swift stdlib doc comments.
     os << "#pragma clang diagnostic push\n";
     os << "#pragma clang diagnostic ignored \"-Wdocumentation\"\n";
@@ -1157,7 +1219,7 @@ EmittedClangHeaderDependencyInfo swift::printModuleContentsAsCxx(
 
   os << "#ifndef SWIFT_PRINTED_CORE\n";
   os << "#define SWIFT_PRINTED_CORE\n";
-  printSwiftToClangCoreScaffold(interopContext, M.getASTContext(),
+  printSwiftToClangCoreScaffold(interopContext, context,
                                 writer.getTypeMapping(), os);
   os << "#endif\n";
 
@@ -1169,9 +1231,9 @@ EmittedClangHeaderDependencyInfo swift::printModuleContentsAsCxx(
       os << "#endif\n";
     os << "#ifdef __cplusplus\n";
     os << "namespace ";
-    ClangSyntaxPrinter(M.getASTContext(), os).printBaseName(&M);
+    ClangSyntaxPrinter(context, os).printBaseName(&M);
     os << " SWIFT_PRIVATE_ATTR";
-    ClangSyntaxPrinter(M.getASTContext(), os).printSymbolUSRAttribute(&M);
+    ClangSyntaxPrinter(context, os).printSymbolUSRAttribute(&M);
     os << " {\n";
     os << "namespace " << cxx_synthesis::getCxxImplNamespaceName() << " {\n";
     os << "extern \"C\" {\n";
@@ -1189,10 +1251,13 @@ EmittedClangHeaderDependencyInfo swift::printModuleContentsAsCxx(
   os << "#pragma clang diagnostic push\n";
   os << "#pragma clang diagnostic ignored \"-Wreserved-identifier\"\n";
   // Construct a C++ namespace for the module.
-  ClangSyntaxPrinter(M.getASTContext(), os).printNamespace(
-      [&](raw_ostream &os) { ClangSyntaxPrinter(M.getASTContext(), os).printBaseName(&M); },
-      [&](raw_ostream &os) { os << moduleOS.str(); },
-      ClangSyntaxPrinter::NamespaceTrivia::AttributeSwiftPrivate, &M);
+  ClangSyntaxPrinter(context, os)
+      .printNamespace(
+          [&](raw_ostream &os) {
+            ClangSyntaxPrinter(context, os).printBaseName(&M);
+          },
+          [&](raw_ostream &os) { os << moduleOS.str(); },
+          ClangSyntaxPrinter::NamespaceTrivia::AttributeSwiftPrivate, &M);
   os << "#pragma clang diagnostic pop\n";
 
   if (M.isStdlibModule()) {
diff --git a/lib/PrintAsClang/ModuleContentsWriter.h b/lib/PrintAsClang/ModuleContentsWriter.h
index f6a175fc4b6e4..0e7edca689caa 100644
--- a/lib/PrintAsClang/ModuleContentsWriter.h
+++ b/lib/PrintAsClang/ModuleContentsWriter.h
@@ -37,6 +37,11 @@ void printModuleContentsAsObjC(raw_ostream &os,
                                ModuleDecl &M,
                                SwiftToClangInteropContext &interopContext);
 
+void printModuleContentsAsC(raw_ostream &os,
+                            llvm::SmallPtrSetImpl<ImportModuleTy> &imports,
+                            ModuleDecl &M,
+                            SwiftToClangInteropContext &interopContext);
+
 struct EmittedClangHeaderDependencyInfo {
     /// The set of imported modules used by this module.
     SmallPtrSet<ImportModuleTy, 8> imports;
diff --git a/lib/PrintAsClang/OutputLanguageMode.h b/lib/PrintAsClang/OutputLanguageMode.h
index 5828aa0306239..b39c625c044a1 100644
--- a/lib/PrintAsClang/OutputLanguageMode.h
+++ b/lib/PrintAsClang/OutputLanguageMode.h
@@ -15,7 +15,7 @@
 
 namespace swift {
 
-enum class OutputLanguageMode { ObjC, Cxx };
+enum class OutputLanguageMode { ObjC, Cxx, C };
 
 } // end namespace swift
 
diff --git a/lib/PrintAsClang/PrimitiveTypeMapping.cpp b/lib/PrintAsClang/PrimitiveTypeMapping.cpp
index dd951f7334d97..705010c66aaf1 100644
--- a/lib/PrintAsClang/PrimitiveTypeMapping.cpp
+++ b/lib/PrintAsClang/PrimitiveTypeMapping.cpp
@@ -13,35 +13,86 @@
 #include "PrimitiveTypeMapping.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/Decl.h"
+#include "swift/AST/Identifier.h"
 #include "swift/AST/Module.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/ClangImporter/ClangImporter.h"
+#include <optional>
 
 using namespace swift;
 
+/// Find the implementation of the named type in the named module if loaded.
+static TypeDecl *findTypeInModuleByName(ASTContext &ctx, Identifier moduleName,
+                                        Identifier typeName) {
+  auto module = ctx.getLoadedModule(moduleName);
+  if (!module)
+    return nullptr;
+
+  // Find all of the declarations with this name in the Swift module.
+  SmallVector<ValueDecl *, 1> results;
+  module->lookupValue(typeName, NLKind::UnqualifiedLookup, results);
+  assert(results.size() <= 1 &&
+         "Expected at most one match for a primitive type");
+  for (auto result : results) {
+    if (auto nominal = dyn_cast<NominalTypeDecl>(result))
+      return nominal;
+
+    if (auto typealias = dyn_cast<TypeAliasDecl>(result))
+      return typealias;
+  }
+
+  return nullptr;
+}
+
 void PrimitiveTypeMapping::initialize(ASTContext &ctx) {
   assert(mappedTypeNames.empty() && "expected empty type map");
+
+  auto addMappedType = [&](Identifier moduleName, Identifier typeName,
+                           FullClangTypeInfo info,
+                           bool applyToUnderlying = true) {
+    auto decl = findTypeInModuleByName(ctx, moduleName, typeName);
+    if (!decl)
+      return;
+
+    // Always map a direct definition match. Either the nominal decl or the
+    // typealias itself.
+    mappedTypeNames[decl] = info;
+
+    // If the underlying type of a typealias doesn't have a type, set it here.
+    // This aims to reproduce the typealias behavior from BuiltinMappedTypes.
+    auto typealias = dyn_cast<TypeAliasDecl>(decl);
+    if (applyToUnderlying && typealias) {
+      auto underlying = typealias->getDeclaredInterfaceType()->getAnyNominal();
+      if (underlying && !mappedTypeNames.contains(underlying))
+        mappedTypeNames[underlying] = info;
+    }
+  };
+
+  // Map stdlib types.
 #define MAP(SWIFT_NAME, CLANG_REPR, NEEDS_NULLABILITY)                         \
-  mappedTypeNames[{ctx.StdlibModuleName, ctx.getIdentifier(#SWIFT_NAME)}] = {  \
-      CLANG_REPR, std::optional<StringRef>(CLANG_REPR),                        \
-      std::optional<StringRef>(CLANG_REPR), NEEDS_NULLABILITY}
+  addMappedType(ctx.StdlibModuleName, ctx.getIdentifier(#SWIFT_NAME),          \
+                {CLANG_REPR, std::optional<StringRef>(CLANG_REPR),             \
+                 std::optional<StringRef>(CLANG_REPR), NEEDS_NULLABILITY})
 #define MAP_C(SWIFT_NAME, OBJC_REPR, C_REPR, NEEDS_NULLABILITY)                \
-  mappedTypeNames[{ctx.StdlibModuleName, ctx.getIdentifier(#SWIFT_NAME)}] = {  \
-      OBJC_REPR, std::optional<StringRef>(C_REPR),                             \
-      std::optional<StringRef>(C_REPR), NEEDS_NULLABILITY}
+  addMappedType(ctx.StdlibModuleName, ctx.getIdentifier(#SWIFT_NAME),          \
+                {OBJC_REPR, std::optional<StringRef>(C_REPR),                  \
+                 std::optional<StringRef>(C_REPR), NEEDS_NULLABILITY})
 #define MAP_CXX(SWIFT_NAME, OBJC_REPR, C_REPR, CXX_REPR, NEEDS_NULLABILITY)    \
-  mappedTypeNames[{ctx.StdlibModuleName, ctx.getIdentifier(#SWIFT_NAME)}] = {  \
-      OBJC_REPR, std::optional<StringRef>(C_REPR),                             \
-      std::optional<StringRef>(CXX_REPR), NEEDS_NULLABILITY}
+  addMappedType(ctx.StdlibModuleName, ctx.getIdentifier(#SWIFT_NAME),          \
+                {OBJC_REPR, std::optional<StringRef>(C_REPR),                  \
+                 std::optional<StringRef>(CXX_REPR), NEEDS_NULLABILITY})
 
   MAP(CBool, "bool", false);
 
   MAP(CChar, "char", false);
-  MAP(CWideChar, "wchar_t", false);
   MAP(CChar8, "char8_t", false);
   MAP(CChar16, "char16_t", false);
   MAP(CChar32, "char32_t", false);
 
+  // Set after CChar32 to prefer char32_t for the shared underlying
+  // Unicode.Scalar. char32_t is stable across platforms.
+  MAP(CWideChar, "wchar_t", false);
+
   MAP(CSignedChar, "signed char", false);
   MAP(CShort, "short", false);
   MAP(CInt, "int", false);
@@ -71,6 +122,8 @@ void PrimitiveTypeMapping::initialize(ASTContext &ctx) {
   MAP(Float32, "float", false);
   MAP(Float64, "double", false);
 
+  MAP(Float16, "_Float16", false);
+
   MAP_CXX(Int, "NSInteger", "ptrdiff_t", "swift::Int", false);
   MAP_CXX(UInt, "NSUInteger", "size_t", "swift::UInt", false);
   MAP_C(Bool, "BOOL", "bool", false);
@@ -79,35 +132,56 @@ void PrimitiveTypeMapping::initialize(ASTContext &ctx) {
   MAP(UnsafeRawPointer, "void const *", true);
   MAP(UnsafeMutableRawPointer, "void *", true);
 
-  Identifier ID_ObjectiveC = ctx.Id_ObjectiveC;
-  mappedTypeNames[{ID_ObjectiveC, ctx.getIdentifier("ObjCBool")}] = {
-      "BOOL", std::nullopt, std::nullopt, false};
-  mappedTypeNames[{ID_ObjectiveC, ctx.getIdentifier("Selector")}] = {
-      "SEL", std::nullopt, std::nullopt, true};
-  mappedTypeNames[{ID_ObjectiveC, ctx.getIdentifier(swift::getSwiftName(
-                                      KnownFoundationEntity::NSZone))}] = {
-      "struct _NSZone *", std::nullopt, std::nullopt, true};
+  // Map other module types.
+
+  addMappedType(ctx.Id_ObjectiveC, ctx.getIdentifier("ObjCBool"),
+                {"BOOL", std::nullopt, std::nullopt, false});
+  addMappedType(ctx.Id_ObjectiveC, ctx.getIdentifier("Selector"),
+                {"SEL", std::nullopt, std::nullopt, true});
+  addMappedType(
+      ctx.Id_ObjectiveC,
+      ctx.getIdentifier(swift::getSwiftName(KnownFoundationEntity::NSZone)),
+      {"struct _NSZone *", std::nullopt, std::nullopt, true});
 
-  mappedTypeNames[{ctx.Id_Darwin, ctx.getIdentifier("DarwinBoolean")}] = {
-      "Boolean", std::nullopt, std::nullopt, false};
+  addMappedType(ctx.Id_Darwin, ctx.getIdentifier("DarwinBoolean"),
+                {"Boolean", std::nullopt, std::nullopt, false});
 
-  mappedTypeNames[{ctx.Id_CoreGraphics, ctx.Id_CGFloat}] = {
-      "CGFloat", std::nullopt, std::nullopt, false};
+  addMappedType(ctx.Id_CoreGraphics, ctx.Id_CGFloat,
+                {"CGFloat", std::nullopt, std::nullopt, false});
 
-  mappedTypeNames[{ctx.Id_CoreFoundation, ctx.Id_CGFloat}] = {
-      "CGFloat", std::nullopt, std::nullopt, false};
+  addMappedType(ctx.Id_CoreFoundation, ctx.Id_CGFloat,
+                {"CGFloat", std::nullopt, std::nullopt, false});
 
   // Use typedefs we set up for SIMD vector types.
 #define MAP_SIMD_TYPE(BASENAME, _, __)                                         \
   StringRef simd2##BASENAME = "swift_" #BASENAME "2";                          \
-  mappedTypeNames[{ctx.Id_simd, ctx.getIdentifier(#BASENAME "2")}] = {         \
-      simd2##BASENAME, simd2##BASENAME, simd2##BASENAME, false};               \
+  addMappedType(                                                               \
+      ctx.Id_simd, ctx.getIdentifier(#BASENAME "2"),                           \
+      {simd2##BASENAME, simd2##BASENAME, simd2##BASENAME, false, true},        \
+      /*applyToUnderlying*/ false);                                            \
+  addMappedType(                                                               \
+      ctx.Id_simd, ctx.getIdentifier("simd_" #BASENAME "2"),                   \
+      {simd2##BASENAME, simd2##BASENAME, simd2##BASENAME, false, true},        \
+      /*applyToUnderlying*/ false);                                            \
   StringRef simd3##BASENAME = "swift_" #BASENAME "3";                          \
-  mappedTypeNames[{ctx.Id_simd, ctx.getIdentifier(#BASENAME "3")}] = {         \
-      simd3##BASENAME, simd3##BASENAME, simd3##BASENAME, false};               \
+  addMappedType(                                                               \
+      ctx.Id_simd, ctx.getIdentifier(#BASENAME "3"),                           \
+      {simd3##BASENAME, simd3##BASENAME, simd3##BASENAME, false, true},        \
+      /*applyToUnderlying*/ false);                                            \
+  addMappedType(                                                               \
+      ctx.Id_simd, ctx.getIdentifier("simd_" #BASENAME "3"),                   \
+      {simd3##BASENAME, simd3##BASENAME, simd3##BASENAME, false, true},        \
+      /*applyToUnderlying*/ false);                                            \
   StringRef simd4##BASENAME = "swift_" #BASENAME "4";                          \
-  mappedTypeNames[{ctx.Id_simd, ctx.getIdentifier(#BASENAME "4")}] = {         \
-      simd4##BASENAME, simd4##BASENAME, simd4##BASENAME, false};
+  addMappedType(                                                               \
+      ctx.Id_simd, ctx.getIdentifier(#BASENAME "4"),                           \
+      {simd4##BASENAME, simd4##BASENAME, simd4##BASENAME, false, true},        \
+      /*applyToUnderlying*/ false);                                            \
+  addMappedType(                                                               \
+      ctx.Id_simd, ctx.getIdentifier("simd_" #BASENAME "4"),                   \
+      {simd4##BASENAME, simd4##BASENAME, simd4##BASENAME, false, true},        \
+      /*applyToUnderlying*/ false);
+
 #include "swift/ClangImporter/SIMDMappedTypes.def"
   static_assert(SWIFT_MAX_IMPORTED_SIMD_ELEMENTS == 4,
                 "must add or remove special name mappings if max number of "
@@ -119,9 +193,11 @@ PrimitiveTypeMapping::getMappedTypeInfoOrNull(const TypeDecl *typeDecl) {
   if (mappedTypeNames.empty())
     initialize(typeDecl->getASTContext());
 
-  Identifier moduleName = typeDecl->getModuleContext()->getName();
-  Identifier name = typeDecl->getName();
-  auto iter = mappedTypeNames.find({moduleName, name});
+  auto nominal = dyn_cast<TypeDecl>(typeDecl);
+  if (!nominal)
+    return nullptr;
+
+  auto iter = mappedTypeNames.find(nominal);
   if (iter == mappedTypeNames.end())
     return nullptr;
   return &iter->second;
@@ -130,7 +206,8 @@ PrimitiveTypeMapping::getMappedTypeInfoOrNull(const TypeDecl *typeDecl) {
 std::optional<PrimitiveTypeMapping::ClangTypeInfo>
 PrimitiveTypeMapping::getKnownObjCTypeInfo(const TypeDecl *typeDecl) {
   if (auto *typeInfo = getMappedTypeInfoOrNull(typeDecl))
-    return ClangTypeInfo{typeInfo->objcName, typeInfo->canBeNullable};
+    return ClangTypeInfo{typeInfo->objcName, typeInfo->canBeNullable,
+                         typeInfo->simd};
   return std::nullopt;
 }
 
@@ -138,7 +215,8 @@ std::optional<PrimitiveTypeMapping::ClangTypeInfo>
 PrimitiveTypeMapping::getKnownCTypeInfo(const TypeDecl *typeDecl) {
   if (auto *typeInfo = getMappedTypeInfoOrNull(typeDecl)) {
     if (typeInfo->cName)
-      return ClangTypeInfo{*typeInfo->cName, typeInfo->canBeNullable};
+      return ClangTypeInfo{*typeInfo->cName, typeInfo->canBeNullable,
+                           typeInfo->simd};
   }
   return std::nullopt;
 }
@@ -147,7 +225,25 @@ std::optional<PrimitiveTypeMapping::ClangTypeInfo>
 PrimitiveTypeMapping::getKnownCxxTypeInfo(const TypeDecl *typeDecl) {
   if (auto *typeInfo = getMappedTypeInfoOrNull(typeDecl)) {
     if (typeInfo->cxxName)
-      return ClangTypeInfo{*typeInfo->cxxName, typeInfo->canBeNullable};
+      return ClangTypeInfo{*typeInfo->cxxName, typeInfo->canBeNullable,
+                           typeInfo->simd};
   }
   return std::nullopt;
 }
+
+std::optional<PrimitiveTypeMapping::ClangTypeInfo>
+PrimitiveTypeMapping::getKnownSIMDTypeInfo(Type t, ASTContext &ctx) {
+  auto vecTy = t->getAs<BuiltinVectorType>();
+  if (!vecTy)
+    return std::nullopt;
+
+  auto elemTy = vecTy->getElementType();
+  auto numElems = vecTy->getNumElements();
+
+  std::string elemTyName = elemTy.getString();
+  // While the element type starts with an upper case, vector types start with
+  // lower case.
+  elemTyName[0] = std::tolower(elemTyName[0]);
+  Identifier swiftName = ctx.getIdentifier("swift_" + elemTyName + std::to_string(numElems));
+  return ClangTypeInfo{swiftName.str(), false, true};
+}
diff --git a/lib/PrintAsClang/PrimitiveTypeMapping.h b/lib/PrintAsClang/PrimitiveTypeMapping.h
index 91f397bd42124..52a156f4dd725 100644
--- a/lib/PrintAsClang/PrimitiveTypeMapping.h
+++ b/lib/PrintAsClang/PrimitiveTypeMapping.h
@@ -13,7 +13,7 @@
 #ifndef SWIFT_PRINTASCLANG_PRIMITIVETYPEMAPPING_H
 #define SWIFT_PRINTASCLANG_PRIMITIVETYPEMAPPING_H
 
-#include "swift/AST/Identifier.h"
+#include "swift/AST/Decl.h"
 #include "swift/Basic/LLVM.h"
 #include "llvm/ADT/DenseMap.h"
 
@@ -21,18 +21,21 @@ namespace swift {
 
 class ASTContext;
 class TypeDecl;
+class Type;
 
 /// Provides a mapping from Swift's primitive types to C / Objective-C / C++
 /// primitive types.
 ///
 /// Certain types have mappings that differ in different language modes.
-/// For example, Swift's `Int` maps to `NSInteger` for Objective-C declarations,
-/// but to something like `intptr_t` or `swift::Int` for C and C++ declarations.
+/// For example, Swift's `Int` maps to `NSInteger` for Objective-C
+/// declarations, but to something like `intptr_t` or `swift::Int` for C and
+/// C++ declarations.
 class PrimitiveTypeMapping {
 public:
   struct ClangTypeInfo {
     StringRef name;
     bool canBeNullable;
+    bool simd;
   };
 
   /// Returns the Objective-C type name and nullability for the given Swift
@@ -47,6 +50,8 @@ class PrimitiveTypeMapping {
   /// primitive type declaration, or \c None if no such type name exists.
   std::optional<ClangTypeInfo> getKnownCxxTypeInfo(const TypeDecl *typeDecl);
 
+  std::optional<ClangTypeInfo> getKnownSIMDTypeInfo(Type t, ASTContext &ctx);
+
 private:
   void initialize(ASTContext &ctx);
 
@@ -58,18 +63,19 @@ class PrimitiveTypeMapping {
     // The C++ name of the Swift type.
     std::optional<StringRef> cxxName;
     bool canBeNullable;
+    bool simd = false;
   };
 
   FullClangTypeInfo *getMappedTypeInfoOrNull(const TypeDecl *typeDecl);
 
-  /// A map from {Module, TypeName} pairs to {C name, C nullability} pairs.
+  /// Associate Swift types to their {name, nullability} in foreign languages.
   ///
   /// This is populated on first use with a list of known Swift types that are
   /// translated directly by the ObjC printer instead of structurally, allowing
   /// it to do things like map 'Int' to 'NSInteger' and 'Float' to 'float'.
   /// In some sense it's the reverse of the ClangImporter's MappedTypes.def.
-  llvm::DenseMap<std::pair<Identifier, Identifier>, FullClangTypeInfo>
-      mappedTypeNames;
+  /// Must be kept aligned with BuiltinMappedTypes.def.
+  llvm::DenseMap<TypeDecl*, FullClangTypeInfo> mappedTypeNames;
 };
 
 } // end namespace swift
diff --git a/lib/PrintAsClang/PrintAsClang.cpp b/lib/PrintAsClang/PrintAsClang.cpp
index 0cfdf1c389708..26be623ed744b 100644
--- a/lib/PrintAsClang/PrintAsClang.cpp
+++ b/lib/PrintAsClang/PrintAsClang.cpp
@@ -58,6 +58,17 @@ static void emitObjCConditional(raw_ostream &out,
   out << "#endif\n";
 }
 
+static void emitExternC(raw_ostream &out,
+                        llvm::function_ref<void()> cCase) {
+  emitCxxConditional(out, [&] {
+    out << "extern \"C\" {\n";
+  });
+  cCase();
+  emitCxxConditional(out, [&] {
+    out << "} // extern \"C\"\n";
+  });
+}
+
 static void writePtrauthPrologue(raw_ostream &os, ASTContext &ctx) {
   emitCxxConditional(os, [&]() {
     ClangSyntaxPrinter(ctx, os).printIgnoredDiagnosticBlock(
@@ -207,6 +218,21 @@ static void writePrologue(raw_ostream &out, ASTContext &ctx,
 
   static_assert(SWIFT_MAX_IMPORTED_SIMD_ELEMENTS == 4,
               "need to add SIMD typedefs here if max elements is increased");
+
+  if (ctx.LangOpts.hasFeature(Feature::CDecl)) {
+    // For C compilers which don’t support nullability attributes, ignore them;
+    // for ones which do, suppress warnings about them being an extension.
+    out << "#if !__has_feature(nullability)\n"
+           "# define _Nonnull\n"
+           "# define _Nullable\n"
+           "# define _Null_unspecified\n"
+           "#elif !defined(__OBJC__)\n"
+           "# pragma clang diagnostic ignored \"-Wnullability-extension\"\n"
+           "#endif\n"
+           "#if !__has_feature(nullability_nullable_result)\n"
+           "# define _Nullable_result _Nullable\n"
+           "#endif\n";
+  }
 }
 
 static int compareImportModulesByName(const ImportModuleTy *left,
@@ -220,7 +246,7 @@ static int compareImportModulesByName(const ImportModuleTy *left,
   if (leftSwiftModule && rightSwiftModule)
     return leftSwiftModule->getName().compare(rightSwiftModule->getName());
 
-  auto *leftClangModule = left->get<const clang::Module *>();
+  auto *leftClangModule = cast<const clang::Module *>(*left);
   assert((isCxx || leftClangModule->isSubModule()) &&
          "top-level modules should use a normal swift::ModuleDecl");
   if (rightSwiftModule) {
@@ -234,7 +260,7 @@ static int compareImportModulesByName(const ImportModuleTy *left,
     return 1;
   }
 
-  auto *rightClangModule = right->get<const clang::Module *>();
+  auto *rightClangModule = cast<const clang::Module *>(*right);
   assert((isCxx || rightClangModule->isSubModule()) &&
          "top-level modules should use a normal swift::ModuleDecl");
 
@@ -383,7 +409,10 @@ writeImports(raw_ostream &out, llvm::SmallPtrSetImpl<ImportModuleTy> &imports,
              const FrontendOptions &frontendOpts,
              clang::HeaderSearch &clangHeaderSearchInfo,
              const llvm::StringMap<StringRef> &exposedModuleHeaderNames,
-             bool useCxxImport = false) {
+             bool useCxxImport = false,
+             bool useNonModularIncludes = false) {
+  useNonModularIncludes |= frontendOpts.EmitClangHeaderWithNonModularIncludes;
+
   // Note: we can't use has_feature(modules) as it's always enabled in C++20
   // mode.
   out << "#if __has_feature(objc_modules)\n";
@@ -420,7 +449,7 @@ writeImports(raw_ostream &out, llvm::SmallPtrSetImpl<ImportModuleTy> &imports,
   llvm::vfs::FileSystem &fileSystem = fileManager.getVirtualFileSystem();
   llvm::ErrorOr<std::string> cwd = fileSystem.getCurrentWorkingDirectory();
 
-  if (frontendOpts.EmitClangHeaderWithNonModularIncludes) {
+  if (useNonModularIncludes) {
     assert(cwd && "Access to current working directory required");
 
     for (auto searchDir = clangHeaderSearchInfo.search_dir_begin();
@@ -472,7 +501,7 @@ writeImports(raw_ostream &out, llvm::SmallPtrSetImpl<ImportModuleTy> &imports,
       }
       if (seenImports.insert(Name).second) {
         out << importDirective << ' ' << Name.str() << importDirectiveLineEnd;
-        if (frontendOpts.EmitClangHeaderWithNonModularIncludes) {
+        if (useNonModularIncludes) {
           if (const clang::Module *underlyingClangModule =
                   swiftModule->findUnderlyingClangModule()) {
             collectClangModuleHeaderIncludes(
@@ -489,13 +518,13 @@ writeImports(raw_ostream &out, llvm::SmallPtrSetImpl<ImportModuleTy> &imports,
         }
       }
     } else {
-      const auto *clangModule = import.get<const clang::Module *>();
+      const auto *clangModule = cast<const clang::Module *>(import);
       assert((useCxxImport || clangModule->isSubModule()) &&
              "top-level modules should use a normal swift::ModuleDecl");
       out << importDirective << ' ';
       ModuleDecl::ReverseFullNameIterator(clangModule).printForward(out);
       out << importDirectiveLineEnd;
-      if (frontendOpts.EmitClangHeaderWithNonModularIncludes) {
+      if (useNonModularIncludes) {
         collectClangModuleHeaderIncludes(
             clangModule, fileManager, requiredTextualIncludes, visitedModules,
             includeDirs, cwd.get());
@@ -503,11 +532,13 @@ writeImports(raw_ostream &out, llvm::SmallPtrSetImpl<ImportModuleTy> &imports,
     }
   }
 
-  if (frontendOpts.EmitClangHeaderWithNonModularIncludes) {
-    out << "#else\n";
-    for (auto header : requiredTextualIncludes) {
+  if (useNonModularIncludes && !requiredTextualIncludes.empty()) {
+    out << "#elif defined(__OBJC__)\n";
+    for (auto header : requiredTextualIncludes)
       out << "#import <" << header << ">\n";
-    }
+    out << "#else\n";
+    for (auto header : requiredTextualIncludes)
+      out << "#include <" << header << ">\n";
   }
   out << "#endif\n\n";
   for (const auto header : textualIncludes) {
@@ -518,8 +549,13 @@ writeImports(raw_ostream &out, llvm::SmallPtrSetImpl<ImportModuleTy> &imports,
     if (bridgingHeader.empty())
       out << "#import <" << M.getName().str() << '/' << M.getName().str()
           << ".h>\n\n";
-    else
-      out << "#import \"" << bridgingHeader << "\"\n\n";
+    else {
+      out << "#if defined(__OBJC__)\n";
+      out << "#import \"" << bridgingHeader << "\"\n";
+      out << "#else\n";
+      out << "#include \"" << bridgingHeader << "\"\n";
+      out << "#endif\n\n";
+    }
   }
 }
 
@@ -577,12 +613,28 @@ bool swift::printAsClangHeader(raw_ostream &os, ModuleDecl *M,
   llvm::PrettyStackTraceString trace("While generating Clang header");
 
   SwiftToClangInteropContext interopContext(*M, irGenOpts);
+  writePrologue(os, M->getASTContext(), computeMacroGuard(M));
+
+  // C content (@c)
+  std::string moduleContentsScratch;
+  if (M->getASTContext().LangOpts.hasFeature(Feature::CDecl)) {
+    SmallPtrSet<ImportModuleTy, 8> imports;
+    llvm::raw_string_ostream cModuleContents{moduleContentsScratch};
+    printModuleContentsAsC(cModuleContents, imports, *M, interopContext);
+
+    llvm::StringMap<StringRef> exposedModuleHeaderNames;
+    writeImports(os, imports, *M, bridgingHeader, frontendOpts,
+                 clangHeaderSearchInfo, exposedModuleHeaderNames,
+                 /*useCxxImport=*/false, /*useNonModularIncludes*/true);
+
+    emitExternC(os, [&] { os << "\n" << cModuleContents.str(); });
+    moduleContentsScratch.clear();
+  }
 
+  // Objective-C content
   SmallPtrSet<ImportModuleTy, 8> imports;
-  std::string objcModuleContentsBuf;
-  llvm::raw_string_ostream objcModuleContents{objcModuleContentsBuf};
+  llvm::raw_string_ostream objcModuleContents{moduleContentsScratch};
   printModuleContentsAsObjC(objcModuleContents, imports, *M, interopContext);
-  writePrologue(os, M->getASTContext(), computeMacroGuard(M));
   emitObjCConditional(os, [&] {
     llvm::StringMap<StringRef> exposedModuleHeaderNames;
     writeImports(os, imports, *M, bridgingHeader, frontendOpts,
@@ -591,6 +643,8 @@ bool swift::printAsClangHeader(raw_ostream &os, ModuleDecl *M,
   writePostImportPrologue(os, *M);
   emitObjCConditional(os, [&] { os << "\n" << objcModuleContents.str(); });
   writeObjCEpilogue(os);
+
+  // C++ content
   emitCxxConditional(os, [&] {
     // FIXME: Expose Swift with @expose by default.
     bool enableCxx = frontendOpts.ClangHeaderExposedDecls.has_value() ||
diff --git a/lib/PrintAsClang/PrintClangFunction.cpp b/lib/PrintAsClang/PrintClangFunction.cpp
index 6dc0a15767776..2d35051cbe57d 100644
--- a/lib/PrintAsClang/PrintClangFunction.cpp
+++ b/lib/PrintAsClang/PrintClangFunction.cpp
@@ -52,48 +52,62 @@ getKnownTypeInfo(const TypeDecl *typeDecl, PrimitiveTypeMapping &typeMapping,
              : typeMapping.getKnownCTypeInfo(typeDecl);
 }
 
-bool isKnownType(Type t, PrimitiveTypeMapping &typeMapping,
-                 OutputLanguageMode languageMode) {
+enum class KnownTypeKind { Known, KnownSIMD, Unknown };
+
+KnownTypeKind isKnownType(Type t, PrimitiveTypeMapping &typeMapping,
+                          OutputLanguageMode languageMode, ASTContext &ctx) {
   if (auto *typeAliasType = dyn_cast<TypeAliasType>(t.getPointer())) {
     auto aliasInfo =
         getKnownTypeInfo(typeAliasType->getDecl(), typeMapping, languageMode);
     if (aliasInfo != std::nullopt)
-      return true;
+      return aliasInfo->simd ? KnownTypeKind::KnownSIMD : KnownTypeKind::Known;
     return isKnownType(typeAliasType->getSinglyDesugaredType(), typeMapping,
-                       languageMode);
+                       languageMode, ctx);
   }
 
   const TypeDecl *typeDecl;
   auto *tPtr = t->isOptional() ? t->getOptionalObjectType()->getDesugaredType()
                                : t->getDesugaredType();
   if (auto *bgt = dyn_cast<BoundGenericStructType>(tPtr)) {
-    return bgt->isUnsafePointer() || bgt->isUnsafeMutablePointer();
+    return (bgt->isUnsafePointer() || bgt->isUnsafeMutablePointer())
+               ? KnownTypeKind::Known
+               : KnownTypeKind::Unknown;
   }
   if (auto *structType = dyn_cast<StructType>(tPtr)) {
     auto nullableInfo =
         getKnownTypeInfo(structType->getDecl(), typeMapping, languageMode);
     if (nullableInfo && nullableInfo->canBeNullable)
-      return true;
+      return nullableInfo->simd ? KnownTypeKind::KnownSIMD
+                                : KnownTypeKind::Known;
   }
   if (auto *classType = dyn_cast<ClassType>(tPtr)) {
-    return classType->getClassOrBoundGenericClass()->hasClangNode() &&
-           isa<clang::ObjCInterfaceDecl>(
-               classType->getClassOrBoundGenericClass()->getClangDecl());
+    return (classType->getClassOrBoundGenericClass()->hasClangNode() &&
+            isa<clang::ObjCInterfaceDecl>(
+                classType->getClassOrBoundGenericClass()->getClangDecl()))
+               ? KnownTypeKind::Known
+               : KnownTypeKind::Unknown;
   }
+  if (t->getAs<BuiltinVectorType>())
+    return typeMapping.getKnownSIMDTypeInfo(t, ctx) ? KnownTypeKind::KnownSIMD
+                                                    : KnownTypeKind::Unknown;
 
   if (auto *structDecl = t->getStructOrBoundGenericStruct())
     typeDecl = structDecl;
   else
-    return false;
-  return getKnownTypeInfo(typeDecl, typeMapping, languageMode) != std::nullopt;
+    return KnownTypeKind::Unknown;
+  return getKnownTypeInfo(typeDecl, typeMapping, languageMode) != std::nullopt
+             ? KnownTypeKind::Known
+             : KnownTypeKind::Unknown;
 }
 
-bool isKnownCxxType(Type t, PrimitiveTypeMapping &typeMapping) {
-  return isKnownType(t, typeMapping, OutputLanguageMode::Cxx);
+KnownTypeKind isKnownCxxType(Type t, PrimitiveTypeMapping &typeMapping,
+                             ASTContext &ctx) {
+  return isKnownType(t, typeMapping, OutputLanguageMode::Cxx, ctx);
 }
 
-bool isKnownCType(Type t, PrimitiveTypeMapping &typeMapping) {
-  return isKnownType(t, typeMapping, OutputLanguageMode::ObjC);
+KnownTypeKind isKnownCType(Type t, PrimitiveTypeMapping &typeMapping,
+                           ASTContext &ctx) {
+  return isKnownType(t, typeMapping, OutputLanguageMode::ObjC, ctx);
 }
 
 struct CFunctionSignatureTypePrinterModifierDelegate {
@@ -151,7 +165,7 @@ class ClangTypeHandler {
   static void
   printGenericReturnScaffold(raw_ostream &os, StringRef templateParamName,
                              llvm::function_ref<void(StringRef)> bodyOfReturn) {
-    printReturnScaffold(nullptr, os, templateParamName, templateParamName,
+    printReturnScaffold(false, os, templateParamName, templateParamName,
                         bodyOfReturn);
   }
 
@@ -165,13 +179,19 @@ class ClangTypeHandler {
       llvm::raw_string_ostream unqualTypeNameOS(typeName);
       unqualTypeNameOS << typeDecl->getName();
     }
-    printReturnScaffold(typeDecl, os, fullQualifiedType, typeName,
+    printReturnScaffold(isTrivial(typeDecl), os, fullQualifiedType, typeName,
                         bodyOfReturn);
   }
 
+  static void
+  printSIMDReturnScaffold(StringRef simdTypeName, raw_ostream &os,
+                          llvm::function_ref<void(StringRef)> bodyOfReturn) {
+    printReturnScaffold(true, os, simdTypeName, simdTypeName, bodyOfReturn);
+  }
+
 private:
   static void
-  printReturnScaffold(const clang::TagDecl *typeDecl, raw_ostream &os,
+  printReturnScaffold(bool isTrivial, raw_ostream &os,
                       StringRef fullQualifiedType, StringRef typeName,
                       llvm::function_ref<void(StringRef)> bodyOfReturn) {
     os << "alignas(alignof(" << fullQualifiedType << ")) char storage[sizeof("
@@ -180,7 +200,7 @@ class ClangTypeHandler {
        << fullQualifiedType << " *>(storage);\n";
     bodyOfReturn("storage");
     os << ";\n";
-    if (isTrivial(typeDecl)) {
+    if (isTrivial) {
       // Trivial object can be just copied and not destroyed.
       os << "return *storageObjectPtr;\n";
       return;
@@ -320,11 +340,16 @@ class CFunctionSignatureTypePrinter
     auto *cd = CT->getDecl();
     if (cd->hasClangNode()) {
       const auto *clangDecl = cd->getClangDecl();
-      ClangSyntaxPrinter(cd->getASTContext(), os).printClangTypeReference(clangDecl);
+      ClangSyntaxPrinter(cd->getASTContext(), os)
+          .printClangTypeReference(clangDecl);
       bool alreadyPointer = false;
       if (const auto *typedefDecl = dyn_cast<clang::TypedefNameDecl>(clangDecl))
         if (importer::isCFTypeDecl(typedefDecl))
           alreadyPointer = true;
+      if (!DeclAndTypePrinter::maybeGetOSObjectBaseName(
+               dyn_cast<clang::NamedDecl>(clangDecl))
+               .empty())
+        alreadyPointer = true;
       os << (alreadyPointer ? " " : " *")
          << (!optionalKind || *optionalKind == OTK_None ? "_Nonnull"
                                                         : "_Nullable");
@@ -463,7 +488,8 @@ class CFunctionSignatureTypePrinter
     llvm::SaveAndRestore<FunctionSignatureTypeUse> typeUseNormal(
         typeUseKind, FunctionSignatureTypeUse::TypeReference);
     // FIXME: We can definitely support pointers to known Clang types.
-    if (!isKnownCType(args.front(), typeMapping))
+    if (isKnownCType(args.front(), typeMapping, BGT->getASTContext()) ==
+        KnownTypeKind::Unknown)
       return ClangRepresentation(ClangRepresentation::unsupported);
     auto partRepr = visitPart(args.front(), OTK_None, /*isInOutParam=*/false);
     if (partRepr.isUnsupported())
@@ -572,9 +598,11 @@ DeclAndTypeClangFunctionPrinter::printClangFunctionReturnType(
 static void addABIRecordToTypeEncoding(llvm::raw_ostream &typeEncodingOS,
                                        clang::CharUnits offset,
                                        clang::CharUnits end, Type t,
-                                       PrimitiveTypeMapping &typeMapping) {
-  auto info =
-      typeMapping.getKnownCTypeInfo(t->getNominalOrBoundGenericNominal());
+                                       PrimitiveTypeMapping &typeMapping,
+                                       ASTContext &ctx) {
+  auto info = typeMapping.getKnownSIMDTypeInfo(t, ctx);
+  if (!info)
+    info = typeMapping.getKnownCTypeInfo(t->getNominalOrBoundGenericNominal());
   assert(info);
   typeEncodingOS << '_';
   for (char c : info->name) {
@@ -605,7 +633,8 @@ static std::string encodeTypeInfo(const T &abiTypeInfo,
   ClangSyntaxPrinter(moduleContext->getASTContext(), typeEncodingOS).printBaseName(moduleContext);
   abiTypeInfo.enumerateRecordMembers(
       [&](clang::CharUnits offset, clang::CharUnits end, Type t) {
-        addABIRecordToTypeEncoding(typeEncodingOS, offset, end, t, typeMapping);
+        addABIRecordToTypeEncoding(typeEncodingOS, offset, end, t, typeMapping,
+                                   moduleContext->getASTContext());
       });
   return std::move(typeEncodingOS.str());
 }
@@ -622,7 +651,8 @@ static bool isOptionalForeignReferenceType(Type ty) {
   if (auto obj = ty->getOptionalObjectType()) {
     if (const auto *cd =
             dyn_cast_or_null<ClassDecl>(obj->getNominalOrBoundGenericNominal()))
-      return cd->isForeignReferenceType();
+      return cd->isForeignReferenceType() ||
+             cd->getForeignClassKind() == ClassDecl::ForeignKind::CFType;
   }
   return false;
 }
@@ -652,7 +682,8 @@ static bool printDirectReturnOrParamCType(
                                              clang::CharUnits end, Type t) {
         lastOffset = offset;
         ++Count;
-        addABIRecordToTypeEncoding(typeEncodingOS, offset, end, t, typeMapping);
+        addABIRecordToTypeEncoding(typeEncodingOS, offset, end, t, typeMapping,
+                                   emittedModule->getASTContext());
       }))
     return false;
   if (isResultType && Count == 0) {
@@ -664,7 +695,8 @@ static bool printDirectReturnOrParamCType(
   assert(Count > 0 && "missing return values");
 
   // FIXME: is this "prettyfying" logic sound for multiple return values?
-  if (isKnownCType(valueType, typeMapping) ||
+  if (isKnownCType(valueType, typeMapping, emittedModule->getASTContext()) ==
+          KnownTypeKind::Known ||
       (Count == 1 && lastOffset.isZero() && !valueType->hasTypeParameter() &&
        (valueType->isAnyClassReferenceType() ||
         isOptionalObjCExistential(valueType) ||
@@ -683,7 +715,10 @@ static bool printDirectReturnOrParamCType(
     abiTypeInfo.enumerateRecordMembers([&](clang::CharUnits offset,
                                            clang::CharUnits end, Type t) {
       auto info =
-          typeMapping.getKnownCTypeInfo(t->getNominalOrBoundGenericNominal());
+          typeMapping.getKnownSIMDTypeInfo(t, emittedModule->getASTContext());
+      if (!info)
+        info =
+            typeMapping.getKnownCTypeInfo(t->getNominalOrBoundGenericNominal());
       os << "  " << info->name;
       if (info->canBeNullable)
         os << " _Nullable";
@@ -812,7 +847,8 @@ ClangRepresentation DeclAndTypeClangFunctionPrinter::printFunctionSignature(
     ClangSyntaxPrinter(FD->getASTContext(), functionSignatureOS).printInlineForThunk();
 
   ClangRepresentation resultingRepresentation =
-      ClangRepresentation::representable;
+      cxx_translation::isObjCxxOnly(FD) ? ClangRepresentation::objcxxonly
+                                        : ClangRepresentation::representable;
 
   // Print out the return type.
   if (FD->hasThrows() && outputLang == OutputLanguageMode::Cxx)
@@ -961,8 +997,8 @@ ClangRepresentation DeclAndTypeClangFunctionPrinter::printFunctionSignature(
                     ->isAnyClassReferenceType());
           if (isConst)
             functionSignatureOS << "const ";
-          if (isKnownCType(param.getParamDecl().getInterfaceType(),
-                           typeMapping) ||
+          if (isKnownCType(param.getParamDecl().getInterfaceType(), typeMapping,
+                           FD->getASTContext()) != KnownTypeKind::Unknown ||
               (!param.getParamDecl().getInterfaceType()->hasTypeParameter() &&
                param.getParamDecl()
                    .getInterfaceType()
@@ -1078,7 +1114,9 @@ void DeclAndTypeClangFunctionPrinter::printCxxToCFunctionParameterUse(
     Type type, StringRef name, const ModuleDecl *moduleContext, bool isInOut,
     bool isIndirect, std::string directTypeEncoding, bool forceSelf) {
   auto namePrinter = [&]() { ClangSyntaxPrinter(moduleContext->getASTContext(), os).printIdentifier(name); };
-  if (!isKnownCxxType(type, typeMapping) &&
+  auto knownTypeKind =
+      isKnownCxxType(type, typeMapping, moduleContext->getASTContext());
+  if (knownTypeKind != KnownTypeKind::Known &&
       !hasKnownOptionalNullableCxxMapping(type)) {
     if (type->is<GenericTypeParamType>()) {
       os << "swift::" << cxx_synthesis::getCxxImplNamespaceName()
@@ -1113,21 +1151,21 @@ void DeclAndTypeClangFunctionPrinter::printCxxToCFunctionParameterUse(
           os << "::" << cxx_synthesis::getCxxImplNamespaceName()
              << "::swift_interop_passDirect_" << directTypeEncoding << '(';
         }
-        if (decl->hasClangNode()) {
-            if (!directTypeEncoding.empty())
-                os << "reinterpret_cast<const char *>(";
-            os << "swift::" << cxx_synthesis::getCxxImplNamespaceName()
-               << "::getOpaquePointer(";
-            namePrinter();
+        if (decl->hasClangNode() || knownTypeKind == KnownTypeKind::KnownSIMD) {
+          if (!directTypeEncoding.empty())
+            os << "reinterpret_cast<const char *>(";
+          os << "swift::" << cxx_synthesis::getCxxImplNamespaceName()
+             << "::getOpaquePointer(";
+          namePrinter();
+          os << ')';
+          if (!directTypeEncoding.empty())
             os << ')';
-            if (!directTypeEncoding.empty())
-                os << ')';
         } else {
-            ClangValueTypePrinter(os, cPrologueOS, interopContext)
-                .printParameterCxxToCUseScaffold(
-                    moduleContext,
-                    [&]() { printTypeImplTypeSpecifier(type, moduleContext); },
-                    namePrinter, forceSelf);
+          ClangValueTypePrinter(os, cPrologueOS, interopContext)
+              .printParameterCxxToCUseScaffold(
+                  moduleContext,
+                  [&]() { printTypeImplTypeSpecifier(type, moduleContext); },
+                  namePrinter, forceSelf);
         }
         if (!directTypeEncoding.empty())
           os << ')';
@@ -1249,7 +1287,10 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
       os << "void **vtable_ = *selfPtr_;\n";
       os << "#endif\n";
       os << "struct FTypeAddress {\n";
-      os << "decltype(" << cxx_synthesis::getCxxImplNamespaceName()
+      os << "decltype(";
+      ClangSyntaxPrinter(moduleContext->getASTContext(), os)
+          .printBaseName(moduleContext);
+      os << "::" << cxx_synthesis::getCxxImplNamespaceName()
          << "::" << swiftSymbolName << ") *";
       if (auto ptrAuthDisc = dispatchInfo->getPointerAuthDiscriminator())
         os << " __ptrauth_swift_class_method_pointer(" << ptrAuthDisc->value
@@ -1459,7 +1500,9 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
 
   // Values types are returned either direcly in their C representation, or
   // indirectly by a pointer.
-  if (!isKnownCxxType(resultTy, typeMapping) &&
+  auto knownTypeKind =
+      isKnownCxxType(resultTy, typeMapping, moduleContext->getASTContext());
+  if (knownTypeKind != KnownTypeKind::Known &&
       !hasKnownOptionalNullableCxxMapping(resultTy)) {
     if (const auto *gtpt = resultTy->getAs<GenericTypeParamType>()) {
       printGenericReturnSequence(os, gtpt, printCallToCFunc);
@@ -1496,6 +1539,16 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
           printCallToCFunc(/*firstParam=*/resultPointerName);
         }
       };
+      if (knownTypeKind == KnownTypeKind::KnownSIMD) {
+        if (auto *typeAliasType =
+                dyn_cast<TypeAliasType>(resultTy.getPointer())) {
+          auto info = getKnownTypeInfo(typeAliasType->getDecl(), typeMapping,
+                                       OutputLanguageMode::Cxx);
+          ClangTypeHandler::printSIMDReturnScaffold(info->name, os,
+                                                    valueTypeReturnThunker);
+          return;
+        }
+      }
       if (decl->hasClangNode()) {
         ClangTypeHandler handler(decl->getClangDecl());
         assert(handler.isRepresentable());
@@ -1776,7 +1829,8 @@ bool DeclAndTypeClangFunctionPrinter::hasKnownOptionalNullableCxxMapping(
         return typeInfo->canBeNullable;
       }
       if (const auto *cd = dyn_cast<ClassDecl>(nominal))
-        if (cd->isForeignReferenceType())
+        if (cd->isForeignReferenceType() ||
+            cd->getForeignClassKind() == ClassDecl::ForeignKind::CFType)
           return true;
       return isa_and_nonnull<clang::ObjCInterfaceDecl>(nominal->getClangDecl());
     }
diff --git a/lib/PrintAsClang/PrintClangValueType.cpp b/lib/PrintAsClang/PrintClangValueType.cpp
index 401673b24094a..d9d900605eab9 100644
--- a/lib/PrintAsClang/PrintClangValueType.cpp
+++ b/lib/PrintAsClang/PrintClangValueType.cpp
@@ -16,12 +16,15 @@
 #include "OutputLanguageMode.h"
 #include "PrimitiveTypeMapping.h"
 #include "SwiftToClangInteropContext.h"
+#include "swift/AST/ASTContext.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/SwiftNameTranslation.h"
 #include "swift/AST/Type.h"
 #include "swift/ClangImporter/ClangImporter.h"
 #include "swift/IRGen/IRABIDetailsProvider.h"
 #include "swift/IRGen/Linking.h"
+#include "clang/AST/Decl.h"
+#include "clang/Basic/Module.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/raw_ostream.h"
 
@@ -31,8 +34,9 @@ using namespace swift;
 static void printCTypeName(raw_ostream &os, const NominalTypeDecl *type) {
   ClangSyntaxPrinter printer(type->getASTContext(), os);
   printer.printModuleNameCPrefix(*type->getParentModule());
-  if (!ClangSyntaxPrinter(type->getASTContext(), os).printNestedTypeNamespaceQualifiers(type))
-    os << "::";
+  if (!ClangSyntaxPrinter(type->getASTContext(), os)
+           .printNestedTypeNamespaceQualifiers(type, /*forC=*/true))
+    os << "_";
   printer.printBaseName(type);
 }
 
@@ -329,33 +333,7 @@ void ClangValueTypePrinter::printValueTypeDecl(
     os << "  }\n";
 
     // FIXME: implement the move assignment.
-    os << "  ";
-    printer.printInlineForThunk();
-    printer.printBaseName(typeDecl);
-    os << " &operator =(";
-    printer.printBaseName(typeDecl);
-    os << " &&other) = delete;\n";
-
     // FIXME: implement the move constructor.
-    os << "  [[noreturn]] ";
-    // NOTE: Do not apply attribute((used))
-    // here to ensure the linker error isn't
-    // forced, so just mark this an inline
-    // helper function instead.
-    printer.printInlineForHelperFunction();
-    printer.printBaseName(typeDecl);
-    os << "(";
-    printer.printBaseName(typeDecl);
-    StringRef moveErrorMessage =
-        "C++ does not support moving a Swift value yet";
-    os << " &&) noexcept {\n  "
-          "swift::_impl::_fatalError_Cxx_move_of_Swift_value_type_not_"
-          "supported_"
-          "yet();\n  swift::_impl::_swift_stdlib_reportFatalError(\"swift\", "
-          "5, "
-          "\""
-       << moveErrorMessage << "\", " << moveErrorMessage.size()
-       << ", 0);\n  abort();\n  }\n";
 
     bodyPrinter();
     if (typeDecl->isStdlibDecl())
@@ -629,29 +607,45 @@ void ClangValueTypePrinter::printTypeGenericTraits(
     bool isOpaqueLayout) {
   auto *NTD = dyn_cast<NominalTypeDecl>(typeDecl);
   ClangSyntaxPrinter printer(typeDecl->getASTContext(), os);
-  // FIXME: avoid popping out of the module's namespace here.
-  os << "} // end namespace \n\n";
-  os << "namespace swift SWIFT_PRIVATE_ATTR {\n";
-
   if (typeDecl->hasClangNode()) {
     /// Print a reference to the type metadata function for a C++ type.
-    ClangSyntaxPrinter(typeDecl->getASTContext(), os).printNamespace(
-        cxx_synthesis::getCxxImplNamespaceName(), [&](raw_ostream &os) {
-          ClangSyntaxPrinter(typeDecl->getASTContext(), os).printCTypeMetadataTypeFunction(
-              typeDecl, typeMetadataFuncName, typeMetadataFuncRequirements);
-        });
+    printer.printParentNamespaceForNestedTypes(typeDecl, [&](raw_ostream &os) {
+      printer.printNamespace(
+          cxx_synthesis::getCxxImplNamespaceName(), [&](raw_ostream &os) {
+            ClangSyntaxPrinter(typeDecl->getASTContext(), os)
+                .printCTypeMetadataTypeFunction(typeDecl, typeMetadataFuncName,
+                                                typeMetadataFuncRequirements);
+          });
+    });
   }
+
+  bool objCxxOnly = false;
+  if (const auto *clangDecl = typeDecl->getClangDecl()) {
+    if (cxx_translation::isObjCxxOnly(clangDecl, typeDecl->getASTContext()))
+      objCxxOnly = true;
+  }
+
+  // FIXME: avoid popping out of the module's namespace here.
+  os << "} // end namespace \n\n";
+  os << "namespace swift SWIFT_PRIVATE_ATTR {\n";
   auto classDecl = dyn_cast<ClassDecl>(typeDecl);
-  bool addPointer =
-      typeDecl->isObjC() || (classDecl && classDecl->isForeignReferenceType());
 
+  bool isOSObject = false;
+  if (const auto nd =
+          dyn_cast_or_null<clang::NamedDecl>(typeDecl->getClangDecl()))
+    isOSObject = !DeclAndTypePrinter::maybeGetOSObjectBaseName(nd).empty();
+  bool addPointer = (typeDecl->isObjC() && !isOSObject) ||
+                    (classDecl && classDecl->isForeignReferenceType());
+
+  if (objCxxOnly)
+    os << "#if defined(__OBJC__)\n";
   os << "#pragma clang diagnostic push\n";
   os << "#pragma clang diagnostic ignored \"-Wc++17-extensions\"\n";
-  if (typeDecl->hasClangNode()) {
+  if (const auto *clangDecl = typeDecl->getClangDecl()) {
     // FIXME: share the code.
     os << "template<>\n";
     os << "inline const constexpr bool isUsableInGenericContext<";
-    printer.printClangTypeReference(typeDecl->getClangDecl());
+    printer.printClangTypeReference(clangDecl);
     if (addPointer)
       os << "*";
     os << "> = true;\n";
@@ -661,8 +655,8 @@ void ClangValueTypePrinter::printTypeGenericTraits(
   os << "struct";
   declAndTypePrinter.printAvailability(os, typeDecl);
   os << " TypeMetadataTrait<";
-  if (typeDecl->hasClangNode()) {
-    printer.printClangTypeReference(typeDecl->getClangDecl());
+  if (const auto *clangDecl = typeDecl->getClangDecl()) {
+    printer.printClangTypeReference(clangDecl);
     if (addPointer)
       os << "*";
   } else {
@@ -675,10 +669,11 @@ void ClangValueTypePrinter::printTypeGenericTraits(
   ClangSyntaxPrinter(typeDecl->getASTContext(), os).printInlineForHelperFunction();
   os << "void * _Nonnull getTypeMetadata() {\n";
   os << "    return ";
-  if (!typeDecl->hasClangNode()) {
+  if (typeDecl->hasClangNode())
+    printer.printBaseName(moduleContext);
+  else
     printer.printBaseName(typeDecl->getModuleContext());
-    os << "::";
-  }
+  os << "::";
   if (!printer.printNestedTypeNamespaceQualifiers(typeDecl))
     os << "::";
   os << cxx_synthesis::getCxxImplNamespaceName() << "::";
@@ -741,6 +736,8 @@ void ClangValueTypePrinter::printTypeGenericTraits(
   }
   os << "} // namespace\n";
   os << "#pragma clang diagnostic pop\n";
+  if (objCxxOnly)
+    os << "#endif // #if defined(__OBJC__)\n";
   os << "} // namespace swift\n";
   os << "\n";
   printer.printModuleNamespaceStart(*moduleContext);
diff --git a/lib/PrintAsClang/_SwiftStdlibCxxOverlay.h b/lib/PrintAsClang/_SwiftStdlibCxxOverlay.h
index 4e1332c20cd22..885bbb3773ad8 100644
--- a/lib/PrintAsClang/_SwiftStdlibCxxOverlay.h
+++ b/lib/PrintAsClang/_SwiftStdlibCxxOverlay.h
@@ -1,4 +1,4 @@
-//===--- _SwiftStlibCxxOverlay.h - Additions for Stdlib ---------*- C++ -*-===//
+//===--- _SwiftStdlibCxxOverlay.h - Additions for Stdlib --------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -38,7 +38,11 @@ SWIFT_INLINE_THUNK T_0_0 get() const
 /// Constructs a Swift string from a C string.
 SWIFT_INLINE_THUNK String(const char *cString) noexcept {
   if (!cString) {
+#ifdef __EmbeddedSwift__
+    auto res = _impl::$eS2SycfC();
+#else
     auto res = _impl::$sS2SycfC();
+#endif
     memcpy(_getOpaquePointer(), &res, sizeof(res));
     return;
   }
@@ -70,13 +74,14 @@ static_assert(sizeof(_impl::_impl_String) >= 0,
 SWIFT_INLINE_THUNK String::operator std::string() const {
   auto u = getUtf8();
   std::string result;
-  result.reserve(u.getCount() + 1);
-  using IndexType = decltype(u.getStartIndex());
-  for (auto s = u.getStartIndex().getEncodedOffset(),
-            e = u.getEndIndex().getEncodedOffset();
-       s != e; s = u.indexOffsetBy(IndexType::init(s), 1).getEncodedOffset()) {
-    result.push_back(u[IndexType::init(s)]);
+  result.reserve(u.getCount());
+
+  auto end_offset = u.getEndIndex().getEncodedOffset();
+  for (auto idx = u.getStartIndex(); idx.getEncodedOffset() < end_offset;
+       idx = u.indexAfter(idx)) {
+    result.push_back(static_cast<char>(u[idx]));
   }
+
   return result;
 }
 
@@ -166,8 +171,13 @@ struct SymbolicP {
 } __attribute__((packed));
 
 SWIFT_INLINE_THUNK const void *_Nullable getErrorMetadata() {
+// We do not care about these symbols being duplicated across multiple shared
+// libraries for now.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunique-object-duplication"
   static SymbolicP errorSymbol;
   static int *_Nonnull got_ss5ErrorMp = &$ss5ErrorMp;
+#pragma clang diagnostic pop
   errorSymbol._1 = 2;
   errorSymbol._2 =
       static_cast<uint32_t>(reinterpret_cast<uintptr_t>(&got_ss5ErrorMp) -
diff --git a/lib/Refactoring/Async/AsyncConverter.cpp b/lib/Refactoring/Async/AsyncConverter.cpp
index 50e093c50be8d..b2e44e5efacfc 100644
--- a/lib/Refactoring/Async/AsyncConverter.cpp
+++ b/lib/Refactoring/Async/AsyncConverter.cpp
@@ -48,7 +48,7 @@ bool AsyncConverter::createLegacyBody() {
   if (!canCreateLegacyBody())
     return false;
 
-  FuncDecl *FD = cast<FuncDecl>(StartNode.get<Decl *>());
+  FuncDecl *FD = cast<FuncDecl>(cast<Decl *>(StartNode));
   OS << tok::l_brace << "\n"; // start function body
   OS << "Task " << tok::l_brace << "\n";
   addHoistedNamedCallback(FD, TopHandler, TopHandler.getNameStr(), [&]() {
@@ -71,7 +71,7 @@ bool AsyncConverter::createLegacyBody() {
 
 bool AsyncConverter::createAsyncWrapper() {
   assert(Buffer.empty() && "AsyncConverter can only be used once");
-  auto *FD = cast<FuncDecl>(StartNode.get<Decl *>());
+  auto *FD = cast<FuncDecl>(cast<Decl *>(StartNode));
 
   // First add the new async function declaration.
   addFuncDecl(FD);
@@ -1429,7 +1429,7 @@ void AsyncConverter::addAwaitCall(const CallExpr *CE,
         convertPattern(P);
         return;
       }
-      OS << newNameFor(Elt.get<const Decl *>());
+      OS << newNameFor(cast<const Decl *>(Elt));
     });
     OS << " " << tok::equal << " ";
   }
diff --git a/lib/Refactoring/Async/AsyncRefactoring.h b/lib/Refactoring/Async/AsyncRefactoring.h
index a754d4ee02e7a..89a7ee2f9375f 100644
--- a/lib/Refactoring/Async/AsyncRefactoring.h
+++ b/lib/Refactoring/Async/AsyncRefactoring.h
@@ -439,7 +439,7 @@ class NodesToPrint {
     if (!hasTrailingReturnOrBreak())
       return;
 
-    auto *Node = Nodes.back().get<Stmt *>();
+    auto *Node = cast<Stmt *>(Nodes.back());
 
     // If this is a return statement with return expression, let's preserve it.
     if (auto *RS = dyn_cast<ReturnStmt>(Node)) {
diff --git a/lib/Refactoring/Async/AsyncRefactorings.cpp b/lib/Refactoring/Async/AsyncRefactorings.cpp
index 5d4f9890194a0..603a1a0cd6be6 100644
--- a/lib/Refactoring/Async/AsyncRefactorings.cpp
+++ b/lib/Refactoring/Async/AsyncRefactorings.cpp
@@ -35,7 +35,7 @@ static CallExpr *findOuterCall(ResolvedCursorInfoPtr CursorInfo) {
   if (Contexts.empty())
     return nullptr;
 
-  CallExpr *CE = dyn_cast<CallExpr>(Contexts[0].get<Expr *>());
+  CallExpr *CE = dyn_cast<CallExpr>(cast<Expr *>(Contexts[0]));
   if (!CE)
     return nullptr;
 
@@ -65,7 +65,7 @@ static FuncDecl *findFunction(ResolvedCursorInfoPtr CursorInfo) {
   if (Contexts.back().isDecl(DeclKind::Param))
     Contexts = Contexts.drop_back();
 
-  auto *FD = dyn_cast_or_null<FuncDecl>(Contexts.back().get<Decl *>());
+  auto *FD = dyn_cast_or_null<FuncDecl>(cast<Decl *>(Contexts.back()));
   if (!FD || isa<AccessorDecl>(FD))
     return nullptr;
 
@@ -121,7 +121,7 @@ bool RefactoringActionConvertCallToAsyncAlternative::performChange() {
   auto Scopes = Finder.getContexts();
   BraceStmt *Scope = nullptr;
   if (!Scopes.empty())
-    Scope = cast<BraceStmt>(Scopes.back().get<Stmt *>());
+    Scope = cast<BraceStmt>(cast<Stmt *>(Scopes.back()));
 
   AsyncConverter Converter(TheFile, SM, DiagEngine, CE, Scope);
   if (!Converter.convert())
diff --git a/lib/Refactoring/ConvertStringConcatenationToInterpolation.cpp b/lib/Refactoring/ConvertStringConcatenationToInterpolation.cpp
index bb8dd67473378..cdc0b19b50f09 100644
--- a/lib/Refactoring/ConvertStringConcatenationToInterpolation.cpp
+++ b/lib/Refactoring/ConvertStringConcatenationToInterpolation.cpp
@@ -21,7 +21,7 @@ findConcatenatedExpressions(const ResolvedRangeInfo &Info, ASTContext &Ctx) {
 
   switch (Info.Kind) {
   case RangeKind::SingleExpression:
-    E = Info.ContainedNodes[0].get<Expr *>();
+    E = cast<Expr *>(Info.ContainedNodes[0]);
     break;
   case RangeKind::PartOfExpression:
     E = Info.CommonExprParent;
diff --git a/lib/Refactoring/ExpandSwitchCases.cpp b/lib/Refactoring/ExpandSwitchCases.cpp
index a01ab6bb781e0..f9b317d4af793 100644
--- a/lib/Refactoring/ExpandSwitchCases.cpp
+++ b/lib/Refactoring/ExpandSwitchCases.cpp
@@ -62,8 +62,8 @@ static bool performCasesExpansionInSwitchStmt(SwitchStmt *SwitchS,
 static SwitchStmt *findEnclosingSwitchStmt(CaseStmt *CS, SourceFile *SF,
                                            DiagnosticEngine &DiagEngine) {
   auto IsSwitch = [](ASTNode Node) {
-    return Node.is<Stmt *>() &&
-           Node.get<Stmt *>()->getKind() == StmtKind::Switch;
+    return isa<Stmt *>(Node) &&
+           cast<Stmt *>(Node)->getKind() == StmtKind::Switch;
   };
   ContextFinder Finder(*SF, CS, IsSwitch);
   Finder.resolve();
@@ -74,7 +74,7 @@ static SwitchStmt *findEnclosingSwitchStmt(CaseStmt *CS, SourceFile *SF,
     return nullptr;
   }
   auto *SwitchS =
-      static_cast<SwitchStmt *>(Finder.getContexts().back().get<Stmt *>());
+      static_cast<SwitchStmt *>(cast<Stmt *>(Finder.getContexts().back()));
   // Make sure that CaseStmt is included in switch that was found.
   auto Cases = SwitchS->getCases();
   auto Default = std::find(Cases.begin(), Cases.end(), CS);
diff --git a/lib/Refactoring/ExtractExprBase.cpp b/lib/Refactoring/ExtractExprBase.cpp
index 36e6746c0c142..d428eddcfd1b7 100644
--- a/lib/Refactoring/ExtractExprBase.cpp
+++ b/lib/Refactoring/ExtractExprBase.cpp
@@ -26,8 +26,8 @@ struct ReferenceCollector : public SourceEntityWalker {
   SmallVector<ValueDecl *, 4> References;
 
   ReferenceCollector(Expr *E) { walk(E); }
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type T,
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type T,
                           ReferenceMetaData Data) override {
     References.emplace_back(D);
     return true;
@@ -158,7 +158,7 @@ swift::refactoring::checkExtractConditions(const ResolvedRangeInfo &RangeInfo,
 
   // Disallow extracting certain kinds of statements.
   if (RangeInfo.Kind == RangeKind::SingleStatement) {
-    Stmt *S = RangeInfo.ContainedNodes[0].get<Stmt *>();
+    Stmt *S = cast<Stmt *>(RangeInfo.ContainedNodes[0]);
 
     // These aren't independent statement.
     if (isa<BraceStmt>(S) || isa<CaseStmt>(S))
@@ -167,7 +167,7 @@ swift::refactoring::checkExtractConditions(const ResolvedRangeInfo &RangeInfo,
 
   // Disallow extracting literals.
   if (RangeInfo.Kind == RangeKind::SingleExpression) {
-    Expr *E = RangeInfo.ContainedNodes[0].get<Expr *>();
+    Expr *E = cast<Expr *>(RangeInfo.ContainedNodes[0]);
 
     // Until implementing the performChange() part of extracting trailing
     // closures, we disable them for now.
@@ -211,7 +211,7 @@ bool RefactoringActionExtractExprBase::performChange() {
   ContextFinder Finder(*TheFile, RangeInfo.ContainedNodes.front(),
                        [](ASTNode N) { return N.isStmt(StmtKind::Brace); });
 
-  auto *SelectedExpr = RangeInfo.ContainedNodes[0].get<Expr *>();
+  auto *SelectedExpr = cast<Expr *>(RangeInfo.ContainedNodes[0]);
   Finder.resolve();
   SourceLoc InsertLoc;
   llvm::SetVector<ValueDecl *> AllVisibleDecls;
@@ -231,7 +231,7 @@ bool RefactoringActionExtractExprBase::performChange() {
 
     // Get the innermost brace statement.
     auto BS =
-        static_cast<BraceStmt *>(Finder.getContexts().back().get<Stmt *>());
+        static_cast<BraceStmt *>(cast<Stmt *>(Finder.getContexts().back()));
 
     // Collect all value decls inside the brace statement.
     Collector.walk(BS);
diff --git a/lib/Refactoring/SyntacticRenameRangeDetails.cpp b/lib/Refactoring/SyntacticRenameRangeDetails.cpp
index 6236956236c1b..efd1ed71ee27b 100644
--- a/lib/Refactoring/SyntacticRenameRangeDetails.cpp
+++ b/lib/Refactoring/SyntacticRenameRangeDetails.cpp
@@ -283,12 +283,12 @@ bool RenameRangeDetailCollector::renameLabelsLenient(
     LabelRanges = LabelRanges.take_front(*FirstTrailingLabel);
 
     for (auto LabelIndex : llvm::reverse(indices(TrailingLabels))) {
+      if (OldNames.empty())
+        return true;
+
       CharSourceRange Label = TrailingLabels[LabelIndex];
 
       if (Label.getByteLength()) {
-        if (OldNames.empty())
-          return true;
-
         while (!labelRangeMatches(Label, LabelRangeType::CompoundName,
                                   OldNames.back())) {
           if ((OldNames = OldNames.drop_back()).empty())
@@ -302,9 +302,6 @@ bool RenameRangeDetailCollector::renameLabelsLenient(
 
       // empty labelled trailing closure label
       if (LabelIndex) {
-        if (OldNames.empty())
-          return true;
-
         while (!OldNames.back().empty()) {
           if ((OldNames = OldNames.drop_back()).empty())
             return true;
@@ -330,6 +327,8 @@ bool RenameRangeDetailCollector::renameLabelsLenient(
 
       // first name pos
       if (!NameIndex) {
+        if (NameIndex >= OldNames.size())
+          return true;
         while (!OldNames[NameIndex].empty()) {
           if (++NameIndex >= OldNames.size())
             return true;
diff --git a/lib/Refactoring/TrailingClosure.cpp b/lib/Refactoring/TrailingClosure.cpp
index 9c1dd789c8d7f..bfaa64da7959b 100644
--- a/lib/Refactoring/TrailingClosure.cpp
+++ b/lib/Refactoring/TrailingClosure.cpp
@@ -34,13 +34,13 @@ static CallExpr *findTrailingClosureTarget(SourceManager &SM,
 
   // If the innermost context is a statement (which will be a BraceStmt per
   // the filtering condition above), drop it.
-  if (contexts.back().is<Stmt *>()) {
+  if (isa<Stmt *>(contexts.back())) {
     contexts = contexts.drop_back();
   }
 
-  if (contexts.empty() || !contexts.back().is<Expr *>())
+  if (contexts.empty() || !isa<Expr *>(contexts.back()))
     return nullptr;
-  CallExpr *CE = cast<CallExpr>(contexts.back().get<Expr *>());
+  CallExpr *CE = cast<CallExpr>(cast<Expr *>(contexts.back()));
 
   // The last argument is a non-trailing closure?
   auto *Args = CE->getArgs();
diff --git a/lib/RemoteAST/CMakeLists.txt b/lib/RemoteAST/CMakeLists.txt
index 0b11264377e41..9609ee53cec5e 100644
--- a/lib/RemoteAST/CMakeLists.txt
+++ b/lib/RemoteAST/CMakeLists.txt
@@ -1,20 +1,6 @@
-if(XCODE)
-  file(GLOB_RECURSE REMOTE_LIB_HEADERS
-    ${SWIFT_SOURCE_DIR}/include/swift/Remote/*.h
-    ${SWIFT_SOURCE_DIR}/include/swift/Remote/*.def)
-
-  set_source_files_properties(${REMOTE_LIB_HEADERS}
-    PROPERTIES
-    HEADER_FILE_ONLY true)
-  source_group("libRemote Headers" FILES ${REMOTE_LIB_HEADERS})
-else()
-  set(REMOTE_LIB_HEADERS)
-endif()
-
 add_swift_host_library(swiftRemoteAST STATIC
   RemoteAST.cpp
-  InProcessMemoryReader.cpp
-  ${REMOTE_LIB_HEADERS})
+  InProcessMemoryReader.cpp)
 target_link_libraries(swiftRemoteAST PUBLIC
   swiftDemangling)
 target_link_libraries(swiftRemoteAST PRIVATE
diff --git a/lib/RemoteAST/InProcessMemoryReader.cpp b/lib/RemoteAST/InProcessMemoryReader.cpp
index 95d262c474785..5cd8060d7bf74 100644
--- a/lib/RemoteAST/InProcessMemoryReader.cpp
+++ b/lib/RemoteAST/InProcessMemoryReader.cpp
@@ -35,5 +35,5 @@ RemoteAddress InProcessMemoryReader::getSymbolAddress(const std::string &name) {
 #else
     auto pointer = dlsym(RTLD_DEFAULT, name.c_str());
 #endif
-    return RemoteAddress(pointer);
+    return RemoteAddress((uint64_t)pointer, RemoteAddress::DefaultAddressSpace);
 }
diff --git a/lib/RemoteAST/RemoteAST.cpp b/lib/RemoteAST/RemoteAST.cpp
index eea29ff27cd76..77fa01a11a86b 100644
--- a/lib/RemoteAST/RemoteAST.cpp
+++ b/lib/RemoteAST/RemoteAST.cpp
@@ -53,7 +53,7 @@ using irgen::Alignment;
 using irgen::Size;
 
 static inline RemoteAddress operator+(RemoteAddress address, Size offset) {
-  return RemoteAddress(address.getAddressData() + offset.getValue());
+  return address + offset.getValue();
 }
 
 namespace {
@@ -437,15 +437,14 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
 
   Result<Type> getTypeForRemoteTypeMetadata(RemoteAddress metadata,
                                             bool skipArtificial) override {
-    if (auto result = Reader.readTypeFromMetadata(metadata.getAddressData(),
-                                                  skipArtificial))
+    if (auto result = Reader.readTypeFromMetadata(metadata, skipArtificial))
       return result;
     return getFailure<Type>();
   }
 
   Result<MetadataKind>
   getKindForRemoteTypeMetadata(RemoteAddress metadata) override {
-    auto result = Reader.readKindFromMetadata(metadata.getAddressData());
+    auto result = Reader.readKindFromMetadata(metadata);
     if (result)
       return *result;
     return getFailure<MetadataKind>();
@@ -453,8 +452,7 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
 
   Result<NominalTypeDecl*>
   getDeclForRemoteNominalTypeDescriptor(RemoteAddress descriptor) override {
-    if (auto result =
-          Reader.readNominalTypeFromDescriptor(descriptor.getAddressData()))
+    if (auto result = Reader.readNominalTypeFromDescriptor(descriptor))
       return dyn_cast<NominalTypeDecl>((GenericTypeDecl *) result);
     return getFailure<NominalTypeDecl*>();
   }
@@ -468,8 +466,7 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
   getOffsetOfTupleElementFromMetadata(RemoteAddress metadata,
                                       unsigned index) override {
     typename Runtime::StoredSize offset;
-    if (Reader.readTupleElementOffset(metadata.getAddressData(),
-                                      index, &offset))
+    if (Reader.readTupleElementOffset(metadata, index, &offset))
       return uint64_t(offset);
     return getFailure<uint64_t>();
   }
@@ -484,17 +481,18 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
 
   Result<RemoteAddress>
   getHeapMetadataForObject(RemoteAddress object) override {
-    auto result = Reader.readMetadataFromInstance(object.getAddressData());
+    auto result = Reader.readMetadataFromInstance(object);
     if (result) return RemoteAddress(*result);
     return getFailure<RemoteAddress>();
   }
 
   Result<OpenedExistential>
   getDynamicTypeAndAddressClassExistential(RemoteAddress object) {
-    auto pointerval = Reader.readResolvedPointerValue(object.getAddressData());
+    auto pointerval = Reader.readResolvedPointerValue(object);
     if (!pointerval)
       return getFailure<OpenedExistential>();
     auto result = Reader.readMetadataFromInstance(*pointerval);
+    ;
     if (!result)
       return getFailure<OpenedExistential>();
     auto typeResult = Reader.readTypeFromMetadata(result.value());
@@ -508,7 +506,7 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
   getDynamicTypeAndAddressErrorExistential(RemoteAddress object,
                                            bool dereference=true) {
     if (dereference) {
-      auto pointerval = Reader.readResolvedPointerValue(object.getAddressData());
+      auto pointerval = Reader.readResolvedPointerValue(object);
       if (!pointerval)
         return getFailure<OpenedExistential>();
       object = RemoteAddress(*pointerval);
@@ -519,8 +517,7 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
     if (!result)
       return getFailure<OpenedExistential>();
 
-    auto typeResult =
-        Reader.readTypeFromMetadata(result->MetadataAddress.getAddressData());
+    auto typeResult = Reader.readTypeFromMetadata(result->MetadataAddress);
     if (!typeResult)
       return getFailure<OpenedExistential>();
 
@@ -531,8 +528,7 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
     auto payloadAddress = result->PayloadAddress;
     if (!result->IsBridgedError &&
         typeResult->getClassOrBoundGenericClass()) {
-      auto pointerval = Reader.readResolvedPointerValue(
-          payloadAddress.getAddressData());
+      auto pointerval = Reader.readResolvedPointerValue(payloadAddress);
       if (!pointerval)
         return getFailure<OpenedExistential>();
 
@@ -549,8 +545,7 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
     if (!result)
       return getFailure<OpenedExistential>();
 
-    auto typeResult =
-        Reader.readTypeFromMetadata(result->MetadataAddress.getAddressData());
+    auto typeResult = Reader.readTypeFromMetadata(result->MetadataAddress);
     if (!typeResult)
       return getFailure<OpenedExistential>();
 
@@ -559,8 +554,7 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
     // of the reference.
     auto payloadAddress = result->PayloadAddress;
     if (typeResult->getClassOrBoundGenericClass()) {
-      auto pointerval = Reader.readResolvedPointerValue(
-          payloadAddress.getAddressData());
+      auto pointerval = Reader.readResolvedPointerValue(payloadAddress);
       if (!pointerval)
         return getFailure<OpenedExistential>();
 
@@ -578,7 +572,7 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
     // 1) Loading a pointer from the input address
     // 2) Reading it as metadata and resolving the type
     // 3) Wrapping the resolved type in an existential metatype.
-    auto pointerval = Reader.readResolvedPointerValue(object.getAddressData());
+    auto pointerval = Reader.readResolvedPointerValue(object);
     if (!pointerval)
       return getFailure<OpenedExistential>();
     auto typeResult = Reader.readTypeFromMetadata(*pointerval);
@@ -634,7 +628,7 @@ class RemoteASTContextConcreteImpl final : public RemoteASTContextImpl {
                                  unsigned ordinal) override {
     auto underlyingType = Reader
                               .readUnderlyingTypeForOpaqueTypeDescriptor(
-                                  opaqueDescriptor.getAddressData(), ordinal)
+                                  opaqueDescriptor, ordinal)
                               .getType();
 
     if (!underlyingType)
diff --git a/lib/SIL/CMakeLists.txt b/lib/SIL/CMakeLists.txt
index 6d11f5518d9e2..dc0b4b1316a69 100644
--- a/lib/SIL/CMakeLists.txt
+++ b/lib/SIL/CMakeLists.txt
@@ -6,7 +6,8 @@ target_link_libraries(swiftSIL PRIVATE
   swiftAST
   swiftClangImporter
   swiftSema
-  swiftSerialization)
+  swiftSerialization
+  swiftSILOptimizer)
 
 add_subdirectory(IR)
 add_subdirectory(Utils)
diff --git a/lib/SIL/IR/AbstractionPattern.cpp b/lib/SIL/IR/AbstractionPattern.cpp
index b27ccc849abe7..e7913e3b735ca 100644
--- a/lib/SIL/IR/AbstractionPattern.cpp
+++ b/lib/SIL/IR/AbstractionPattern.cpp
@@ -1366,7 +1366,14 @@ AbstractionPattern::getFunctionThrownErrorType(
     if (!substErrorType)
       return std::nullopt;
 
-    return std::make_pair(AbstractionPattern(*substErrorType),
+    // FIXME: This is actually unsound. The most opaque form of
+    // `(T) throws(U) -> V` should actually be
+    // `(T) throws(any Error) -> V`.
+    auto pattern = ((*substErrorType)->isErrorExistentialType()
+                    ? AbstractionPattern(*substErrorType)
+                    : AbstractionPattern::getOpaque());
+
+    return std::make_pair(pattern,
                           (*substErrorType)->getCanonicalType());
   }
 
@@ -2423,7 +2430,8 @@ class SubstFunctionTypePatternVisitor
       paramKind = GenericTypeParamKind::Pack;
     }
 
-    auto gp = GenericTypeParamType::get(paramKind, 0, paramIndex, Type(),
+    auto gp = GenericTypeParamType::get(paramKind, /*depth=*/0, paramIndex,
+                                        /*weight=*/0, /*valueType=*/Type(),
                                         TC.Context);
     substGenericParams.push_back(gp);
 
diff --git a/lib/SIL/IR/ApplySite.cpp b/lib/SIL/IR/ApplySite.cpp
index 264ed5dd66d53..dfdbde259983d 100644
--- a/lib/SIL/IR/ApplySite.cpp
+++ b/lib/SIL/IR/ApplySite.cpp
@@ -45,3 +45,12 @@ void ApplySite::insertAfterApplication(
   llvm_unreachable("covered switch isn't covered");
 }
 
+bool ApplySite::isAddressable(const Operand &operand) const {
+  unsigned calleeArgIndex = getCalleeArgIndex(operand);
+  assert(calleeArgIndex >= getSubstCalleeConv().getSILArgIndexOfFirstParam());
+  unsigned paramIdx =
+    calleeArgIndex - getSubstCalleeConv().getSILArgIndexOfFirstParam();
+
+  CanSILFunctionType calleeType = getSubstCalleeType();
+  return calleeType->isAddressable(paramIdx, getFunction());
+}
diff --git a/lib/SIL/IR/Bridging.cpp b/lib/SIL/IR/Bridging.cpp
index d7c948a7dcf42..0c7d0a7d0caf1 100644
--- a/lib/SIL/IR/Bridging.cpp
+++ b/lib/SIL/IR/Bridging.cpp
@@ -240,7 +240,7 @@ Type TypeConverter::getLoweredCBridgedType(AbstractionPattern pattern,
     assert(conformance && "Missing conformance?");
     Type bridgedTy =
       ProtocolConformanceRef(conformance).getTypeWitnessByName(
-        t, M.getASTContext().Id_ObjectiveCType);
+        M.getASTContext().Id_ObjectiveCType);
     if (purpose == BridgedTypePurpose::ForResult && clangTy)
       bridgedTy = OptionalType::get(bridgedTy);
     return bridgedTy;
diff --git a/lib/SIL/IR/Linker.cpp b/lib/SIL/IR/Linker.cpp
index 87f64476ad929..c391114e05ee7 100644
--- a/lib/SIL/IR/Linker.cpp
+++ b/lib/SIL/IR/Linker.cpp
@@ -141,6 +141,20 @@ void SILLinkerVisitor::maybeAddFunctionToWorklist(
       // are also set to IsSerialized.
       Worklist.push_back(F);
     }
+
+    if (F->markedAsAlwaysEmitIntoClient()) {
+      // For @_alwaysEmitIntoClient functions, we need to lookup its
+      // differentiability witness and, if present, ask SILLoader to obtain its
+      // definition. Otherwise, a linker error would occur due to undefined
+      // reference to these symbols.
+      for (SILDifferentiabilityWitness *witness :
+           F->getModule().lookUpDifferentiabilityWitnessesForFunction(
+               F->getName())) {
+        F->getModule().getSILLoader()->lookupDifferentiabilityWitness(
+            witness->getKey());
+      }
+    }
+
     return;
   }
 
@@ -159,9 +173,23 @@ void SILLinkerVisitor::maybeAddFunctionToWorklist(
   // HiddenExternal linkage when they are declarations, then they
   // become Shared after the body has been deserialized.
   // So try deserializing HiddenExternal functions too.
-  if (linkage == SILLinkage::HiddenExternal)
-    return deserializeAndPushToWorklist(F);
-  
+  if (linkage == SILLinkage::HiddenExternal) {
+    deserializeAndPushToWorklist(F);
+    if (!F->markedAsAlwaysEmitIntoClient())
+      return;
+    // For @_alwaysEmitIntoClient functions, we need to lookup its
+    // differentiability witness and, if present, ask SILLoader to obtain its
+    // definition. Otherwise, a linker error would occur due to undefined
+    // reference to these symbols.
+    for (SILDifferentiabilityWitness *witness :
+         F->getModule().lookUpDifferentiabilityWitnessesForFunction(
+             F->getName())) {
+      F->getModule().getSILLoader()->lookupDifferentiabilityWitness(
+          witness->getKey());
+    }
+    return;
+  }
+
   // Update the linkage of the function in case it's different in the serialized
   // SIL than derived from the AST. This can be the case with cross-module-
   // optimizations.
@@ -299,7 +327,8 @@ void SILLinkerVisitor::visitProtocolConformance(
 
       SILLinkage linkage = getLinkageForProtocolConformance(rootC, NotForDefinition);
       WT = SILWitnessTable::create(Mod, linkage,
-                                   const_cast<RootProtocolConformance *>(rootC));
+                                   const_cast<RootProtocolConformance *>(rootC),
+                                   /*specialized=*/ false);
     }
     // If the module is at or past the Lowered stage, then we can't do any
     // further deserialization, since pre-IRGen SIL lowering changes the types
@@ -342,8 +371,10 @@ void SILLinkerVisitor::visitProtocolConformance(
     // reading in most conformances until we need them for devirtualization.
     // However, we *must* pull in shared clang-importer-derived conformances
     // we potentially use, since we may not otherwise have a local definition.
-    if (mustDeserializeProtocolConformance(Mod, c))
+    if ((isEmbedded && referencedFromInitExistential) ||
+        mustDeserializeProtocolConformance(Mod, c)) {
       visitProtocolConformance(c, referencedFromInitExistential);
+    }
   };
   
   // For each entry in the witness table...
@@ -427,6 +458,24 @@ void SILLinkerVisitor::visitInitExistentialRefInst(
   }
 }
 
+void SILLinkerVisitor::visitBuiltinInst(BuiltinInst *bi) {
+  switch (bi->getBuiltinInfo().ID) {
+    case BuiltinValueKind::BuildOrdinaryTaskExecutorRef:
+    case BuiltinValueKind::BuildOrdinarySerialExecutorRef:
+    case BuiltinValueKind::BuildComplexEqualitySerialExecutorRef:
+      if (Mod.getOptions().EmbeddedSwift) {
+        // Those builtins act like init_existential_ref instructions and therefore
+        // it's important to have the Executor witness tables available in embedded
+        // mode.
+        auto executorConf = bi->getSubstitutions().getConformances()[0];
+        visitProtocolConformance(executorConf, true);
+      }
+      break;
+    default:
+      break;
+  }
+}
+
 void SILLinkerVisitor::visitAllocRefDynamicInst(AllocRefDynamicInst *ARI) {
   if (!isLinkAll())
     return;
diff --git a/lib/SIL/IR/Linker.h b/lib/SIL/IR/Linker.h
index 982d2aff703b5..f90c73fdf6f97 100644
--- a/lib/SIL/IR/Linker.h
+++ b/lib/SIL/IR/Linker.h
@@ -129,6 +129,7 @@ class SILLinkerVisitor : public SILInstructionVisitor<SILLinkerVisitor, void> {
   }
   void visitInitExistentialAddrInst(InitExistentialAddrInst *IEI);
   void visitInitExistentialRefInst(InitExistentialRefInst *IERI);
+  void visitBuiltinInst(BuiltinInst *bi);
   void visitAllocRefInst(AllocRefInst *ARI);
   void visitAllocRefDynamicInst(AllocRefDynamicInst *ARI);
   void visitMetatypeInst(MetatypeInst *MI);
diff --git a/lib/SIL/IR/OperandOwnership.cpp b/lib/SIL/IR/OperandOwnership.cpp
index fcee5da5c0314..2d85b8a910720 100644
--- a/lib/SIL/IR/OperandOwnership.cpp
+++ b/lib/SIL/IR/OperandOwnership.cpp
@@ -171,6 +171,7 @@ OPERAND_OWNERSHIP(TrivialUse, DestroyAddr)
 OPERAND_OWNERSHIP(TrivialUse, EndAccess)
 OPERAND_OWNERSHIP(TrivialUse, EndUnpairedAccess)
 OPERAND_OWNERSHIP(TrivialUse, GetAsyncContinuationAddr)
+OPERAND_OWNERSHIP(TrivialUse, VectorBaseAddr)
 OPERAND_OWNERSHIP(TrivialUse, IndexAddr)
 OPERAND_OWNERSHIP(TrivialUse, IndexRawPointer)
 OPERAND_OWNERSHIP(TrivialUse, InitBlockStorageHeader)
@@ -301,6 +302,7 @@ OPERAND_OWNERSHIP(DestroyingConsume, DestroyNotEscapedClosure)
 OPERAND_OWNERSHIP(DestroyingConsume, EndLifetime)
 OPERAND_OWNERSHIP(DestroyingConsume, BeginCOWMutation)
 OPERAND_OWNERSHIP(DestroyingConsume, EndCOWMutation)
+OPERAND_OWNERSHIP(TrivialUse, EndCOWMutationAddr)
 OPERAND_OWNERSHIP(DestroyingConsume, EndInitLetRef)
 // The move_value instruction creates a distinct lifetime.
 OPERAND_OWNERSHIP(DestroyingConsume, MoveValue)
@@ -482,7 +484,8 @@ OperandOwnershipClassifier::visitDropDeinitInst(DropDeinitInst *i) {
 // This does not apply to uses that begin an explicit borrow scope in the
 // caller, such as begin_apply.
 static OperandOwnership getFunctionArgOwnership(SILArgumentConvention argConv,
-                                                bool hasScopeInCaller) {
+                                                bool hasScopeInCaller,
+                                                bool forwardsGuaranteedValues) {
 
   switch (argConv) {
   case SILArgumentConvention::Indirect_In_CXX:
@@ -499,7 +502,6 @@ static OperandOwnership getFunctionArgOwnership(SILArgumentConvention argConv,
   // explicit borrow scope in the caller so we must treat arguments passed to it
   // as being borrowed for the entire region of coroutine execution.
   case SILArgumentConvention::Indirect_In_Guaranteed:
-  case SILArgumentConvention::Direct_Guaranteed:
   case SILArgumentConvention::Pack_Guaranteed:
   case SILArgumentConvention::Pack_Inout:
   case SILArgumentConvention::Pack_Out:
@@ -508,6 +510,16 @@ static OperandOwnership getFunctionArgOwnership(SILArgumentConvention argConv,
     return hasScopeInCaller ? OperandOwnership::Borrow
                             : OperandOwnership::InstantaneousUse;
 
+  case SILArgumentConvention::Direct_Guaranteed: {
+    if (hasScopeInCaller) {
+      return OperandOwnership::Borrow;
+    }
+    if (forwardsGuaranteedValues) {
+      return OperandOwnership::GuaranteedForwarding;
+    }
+    return OperandOwnership::InstantaneousUse;
+  }
+
   case SILArgumentConvention::Direct_Unowned:
     return OperandOwnership::UnownedInstantaneousUse;
 
@@ -539,7 +551,8 @@ OperandOwnershipClassifier::visitFullApply(FullApplySite apply) {
   }();
 
   auto argOwnership = getFunctionArgOwnership(
-    argConv, /*hasScopeInCaller*/ apply.beginsCoroutineEvaluation());
+      argConv, /*hasScopeInCaller*/ apply.beginsCoroutineEvaluation(),
+      /*forwardsGuaranteedValues*/ apply.hasGuaranteedResult());
 
   // OSSA cleanup needs to handle each of these callee ownership cases.
   //
@@ -602,14 +615,16 @@ OperandOwnership OperandOwnershipClassifier::visitYieldInst(YieldInst *i) {
   auto fnType = i->getFunction()->getLoweredFunctionType();
   SILArgumentConvention argConv(
     fnType->getYields()[getOperandIndex()].getConvention());
-  return getFunctionArgOwnership(argConv, /*hasScopeInCaller*/ false);
+  return getFunctionArgOwnership(argConv, /*hasScopeInCaller*/ false,
+                                 /*forwardsGuaranteedValues*/ false);
 }
 
 OperandOwnership OperandOwnershipClassifier::visitReturnInst(ReturnInst *i) {
   switch (i->getOwnershipKind()) {
   case OwnershipKind::Any:
-  case OwnershipKind::Guaranteed:
     llvm_unreachable("invalid value ownership");
+  case OwnershipKind::Guaranteed:
+    return OperandOwnership::GuaranteedForwarding;
   case OwnershipKind::None:
     return OperandOwnership::TrivialUse;
   case OwnershipKind::Unowned:
@@ -627,17 +642,6 @@ OperandOwnership OperandOwnershipClassifier::visitAssignInst(AssignInst *i) {
   return OperandOwnership::DestroyingConsume;
 }
 
-OperandOwnership
-OperandOwnershipClassifier::visitAssignByWrapperInst(AssignByWrapperInst *i) {
-  if (getValue() == i->getSrc()) {
-    return OperandOwnership::DestroyingConsume;
-  }
-  if (getValue() == i->getDest()) {
-    return OperandOwnership::TrivialUse;
-  }
-  return OperandOwnership::InstantaneousUse; // initializer/setter closure
-}
-
 OperandOwnership
 OperandOwnershipClassifier::visitAssignOrInitInst(AssignOrInitInst *i) {
   if (getValue() == i->getSrc()) {
@@ -885,7 +889,10 @@ BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, SToUCheckedTrunc)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, Expect)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, Shl)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, GenericShl)
+BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, Select)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, ShuffleVector)
+BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, Interleave)
+BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, Deinterleave)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, Sizeof)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, StaticReport)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, Strideof)
@@ -914,6 +921,7 @@ BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, GenericXor)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, ZExt)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, ZExtOrBitCast)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, ZeroInitializer)
+BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, PrepareInitialization)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, PoundAssert)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, GlobalStringTablePointer)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, TypePtrAuthDiscriminator)
diff --git a/lib/SIL/IR/SIL.cpp b/lib/SIL/IR/SIL.cpp
index 27f4cca661ee2..d03ee74f91f7d 100644
--- a/lib/SIL/IR/SIL.cpp
+++ b/lib/SIL/IR/SIL.cpp
@@ -18,6 +18,7 @@
 #include "swift/SIL/SILUndef.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/AnyFunctionRef.h"
+#include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/Pattern.h"
@@ -287,7 +288,7 @@ static bool isTypeMetadataForLayoutAccessible(SILModule &M, SILType type) {
 bool SILModule::isTypeABIAccessible(SILType type,
                                     TypeExpansionContext forExpansion) {
   // Fixed-ABI types can have value operations done without metadata.
-  if (Types.getTypeLowering(type, forExpansion).isFixedABI())
+  if (Types.getTypeProperties(type, forExpansion).isFixedABI())
     return true;
 
   assert(!type.is<ReferenceStorageType>() &&
@@ -307,18 +308,106 @@ bool SILModule::isTypeMetadataForLayoutAccessible(SILType type) {
   return ::isTypeMetadataForLayoutAccessible(*this, type);
 }
 
-static bool isUnsupportedKeyPathValueType(Type ty) {
+// Given the type `ty`, which should be in the generic environment of the signature
+// `sig`, return a generic signature with all of the requirements of `sig`,
+// combined with all of the requirements necessary for `ty` to be both
+// `Copyable` and `Escapable`, if possible. Returns `nullopt` if the type
+// can never be both Copyable and Escapable.
+static std::optional<GenericSignature>
+getKeyPathSupportingGenericSignature(Type ty, GenericSignature contextSig) {
+  auto &C = ty->getASTContext();
+  
+  // If the type is already unconditionally Copyable and Escapable, we don't
+  // need any further requirements.
+  if (ty->isCopyable() && ty->isEscapable()) {
+    return contextSig;
+  }
+  
+  ProtocolConformanceRef copyable, escapable;
+  auto copyableProtocol = C.getProtocol(KnownProtocolKind::Copyable);
+  auto escapableProtocol = C.getProtocol(KnownProtocolKind::Escapable);
+  
+  // If the type is an archetype, then it just needs Copyable and Escapable
+  // constraints imposed.
+  if (ty->is<ArchetypeType>()) {
+    copyable = ProtocolConformanceRef::forAbstract(ty->mapTypeOutOfContext(),
+                                                   copyableProtocol);
+    escapable = ProtocolConformanceRef::forAbstract(ty->mapTypeOutOfContext(),
+                                                    escapableProtocol);
+  } else {
+    // Look for any conditional conformances.
+    copyable = lookupConformance(ty, copyableProtocol);
+    escapable = lookupConformance(ty, escapableProtocol);
+  }
+
+  // If the type is never copyable or escapable, that's it.
+  if (copyable.isInvalid() || escapable.isInvalid()) {
+    return std::nullopt;
+  }
+  
+  // Otherwise, let's see if we get a viable generic signature combining the
+  // requirements for those conformances with the requirements of the
+  // declaration context.
+  SmallVector<Requirement, 2> ceRequirements;
+
+  auto getRequirementsFromConformance = [&](ProtocolConformanceRef ref) {
+    if (ref.isAbstract()) {
+      // The only requirements are that the abstract type itself be copyable
+      // and escapable.
+      ceRequirements.push_back(Requirement(RequirementKind::Conformance,
+               ty->mapTypeOutOfContext(), copyableProtocol->getDeclaredType()));
+      ceRequirements.push_back(Requirement(RequirementKind::Conformance,
+              ty->mapTypeOutOfContext(), escapableProtocol->getDeclaredType()));
+      return;
+    }
+    
+    if (!ref.isConcrete()) {
+      return;
+    }
+    auto conformance = ref.getConcrete();
+    
+    for (auto reqt : conformance->getRootConformance()
+                                ->getConditionalRequirements()) {
+      ceRequirements.push_back(reqt);
+    }
+  };
+  getRequirementsFromConformance(copyable);
+  getRequirementsFromConformance(escapable);
+
+  auto regularSignature = buildGenericSignatureWithError(C,
+                                               contextSig,
+                                               {},
+                                               std::move(ceRequirements),
+                                               /*allowInverses*/ false);
+  
+  // If the resulting signature has conflicting requirements, then it is
+  // impossible for the type to be copyable and equatable.
+  if (regularSignature.getInt()) {
+    return std::nullopt;
+  }
+  
+  // Otherwise, we have the signature we're looking for.
+  return regularSignature.getPointer();
+}
+
+static std::optional<GenericSignature>
+getKeyPathSupportingGenericSignatureForValueType(Type ty,
+                                                 GenericSignature sig) {
+  std::optional<GenericSignature> contextSig = sig;
+  
   // Visit lowered positions.
   if (auto tupleTy = ty->getAs<TupleType>()) {
     for (auto eltTy : tupleTy->getElementTypes()) {
       if (eltTy->is<PackExpansionType>())
-        return true;
+        return std::nullopt;
 
-      if (isUnsupportedKeyPathValueType(eltTy))
-        return true;
+      contextSig = getKeyPathSupportingGenericSignatureForValueType(
+                                                            eltTy, *contextSig);
+      if (!contextSig)
+        return std::nullopt;
     }
 
-    return false;
+    return contextSig;
   }
 
   if (auto objTy = ty->getOptionalObjectType())
@@ -330,66 +419,78 @@ static bool isUnsupportedKeyPathValueType(Type ty) {
     for (auto param : funcTy->getParams()) {
       auto paramTy = param.getPlainType();
       if (paramTy->is<PackExpansionType>())
-        return true;
+        return std::nullopt;
 
-      if (isUnsupportedKeyPathValueType(paramTy))
-        return true;
+      contextSig = getKeyPathSupportingGenericSignatureForValueType(paramTy,
+                                                                    *contextSig);
+      if (!contextSig) {
+        return std::nullopt;
+      }
     }
 
-    if (isUnsupportedKeyPathValueType(funcTy->getResult()))
-      return true;
+    contextSig = getKeyPathSupportingGenericSignatureForValueType(funcTy->getResult(),
+                                                                  *contextSig);
+
+    if (!contextSig) {
+      return std::nullopt;
+    }
   }
 
   // Noncopyable types aren't supported by key paths in their current form.
   // They would also need a new ABI that's yet to be implemented in order to
   // be properly supported, so let's suppress the descriptor for now if either
   // the container or storage type of the declaration is non-copyable.
-  if (ty->isNoncopyable())
-    return true;
-
-  return false;
+  return getKeyPathSupportingGenericSignature(ty, *contextSig);
 }
 
-bool AbstractStorageDecl::exportsPropertyDescriptor() const {
+std::optional<GenericSignature>
+AbstractStorageDecl::getPropertyDescriptorGenericSignature() const {
   // The storage needs a descriptor if it sits at a module's ABI boundary,
-  // meaning it has public linkage.
+  // meaning it has public linkage, and it is eligible to be part of a key path.
   
-  if (!isStatic()) {
-    if (auto contextTy = getDeclContext()->getDeclaredTypeInContext()) {
-      if (contextTy->isNoncopyable()) {
-        return false;
-      }
+  auto contextTy = getDeclContext()->getDeclaredTypeInContext();
+  auto contextSig = getInnermostDeclContext()->getGenericSignatureOfContext();
+  
+  // If the root type is never `Copyable` or `Escapable`, then instance
+  // members can't be used in key paths, at least as they are implemented
+  // today.
+  if (!isStatic() && contextTy) {
+    auto ceContextSig = getKeyPathSupportingGenericSignature(contextTy,
+                                                             contextSig);
+    if (!ceContextSig) {
+      return std::nullopt;
     }
+    contextSig = *ceContextSig;
   }
 
   // TODO: Global properties ought to eventually be referenceable
   // as key paths from ().
   if (!getDeclContext()->isTypeContext())
-    return false;
+    return std::nullopt;
   
   // Protocol requirements do not need property descriptors.
   if (isa<ProtocolDecl>(getDeclContext()))
-    return false;
+    return std::nullopt;
 
   // Static properties declared directly in protocol do not need
   // descriptors as existential Any.Type will not resolve to a value.
   if (isStatic() && isa<ProtocolDecl>(getDeclContext()))
-    return false;
+    return std::nullopt;
 
   // FIXME: We should support properties and subscripts with '_read' accessors;
   // 'get' is not part of the opaque accessor set there.
   auto *getter = getOpaqueAccessor(AccessorKind::Get);
   if (!getter)
-    return false;
+    return std::nullopt;
 
   // If the getter is mutating, we cannot form a keypath to it at all.
   if (isGetterMutating())
-    return false;
+    return std::nullopt;
 
   // If the storage is an ABI-compatible override of another declaration, we're
   // not going to be emitting a property descriptor either.
   if (!isValidKeyPathComponent())
-    return false;
+    return std::nullopt;
 
   // TODO: If previous versions of an ABI-stable binary needed the descriptor,
   // then we still do.
@@ -409,7 +510,7 @@ bool AbstractStorageDecl::exportsPropertyDescriptor() const {
   case SILLinkage::Private:
   case SILLinkage::Hidden:
     // Don't need a public descriptor.
-    return false;
+    return std::nullopt;
     
   case SILLinkage::HiddenExternal:
   case SILLinkage::PublicExternal:
@@ -417,19 +518,22 @@ bool AbstractStorageDecl::exportsPropertyDescriptor() const {
     llvm_unreachable("should be definition linkage?");
   }
 
-  auto typeInContext = getInnermostDeclContext()->mapTypeIntoContext(
+  auto typeInContext = contextSig.getGenericEnvironment()->mapTypeIntoContext(
       getValueInterfaceType());
-  if (isUnsupportedKeyPathValueType(typeInContext)) {
-    return false;
+  auto valueTypeSig = getKeyPathSupportingGenericSignatureForValueType(typeInContext, contextSig);
+  if (!valueTypeSig) {
+    return std::nullopt;
   }
+  contextSig = *valueTypeSig;
 
   // Subscripts with inout arguments (FIXME)and reabstracted arguments(/FIXME)
   // don't have descriptors either.
   if (auto sub = dyn_cast<SubscriptDecl>(this)) {
     for (auto *index : *sub->getIndices()) {
       // Keypaths can't capture inout indices.
-      if (index->isInOut())
-        return false;
+      if (index->isInOut()) {
+        return std::nullopt;
+      }
       
       auto indexTy = index->getInterfaceType()
                         ->getReducedType(sub->getGenericSignatureOfContext());
@@ -439,7 +543,7 @@ bool AbstractStorageDecl::exportsPropertyDescriptor() const {
       // had only one abstraction level and no explosion.
       
       if (isa<TupleType>(indexTy))
-        return false;
+        return std::nullopt;
       
       auto indexObjTy = indexTy;
       if (auto objTy = indexObjTy.getOptionalObjectType())
@@ -447,9 +551,9 @@ bool AbstractStorageDecl::exportsPropertyDescriptor() const {
       
       if (isa<AnyFunctionType>(indexObjTy)
           || isa<AnyMetatypeType>(indexObjTy))
-        return false;
+        return std::nullopt;
     }
   }
 
-  return true;
+  return contextSig;
 }
diff --git a/lib/SIL/IR/SILArgument.cpp b/lib/SIL/IR/SILArgument.cpp
index 1b0ccdcf4908a..8122b5b1b5e0d 100644
--- a/lib/SIL/IR/SILArgument.cpp
+++ b/lib/SIL/IR/SILArgument.cpp
@@ -37,6 +37,7 @@ SILArgument::SILArgument(ValueKind subClassKind,
   sharedUInt8().SILArgument.reborrow = reborrow;
   sharedUInt8().SILArgument.pointerEscape = pointerEscape;
   inputParentBlock->insertArgument(inputParentBlock->args_end(), this);
+  ASSERT(!type.hasTypeParameter());
 }
 
 SILFunction *SILArgument::getFunction() {
diff --git a/lib/SIL/IR/SILBasicBlock.cpp b/lib/SIL/IR/SILBasicBlock.cpp
index 2962cab39271f..dcafa32e27118 100644
--- a/lib/SIL/IR/SILBasicBlock.cpp
+++ b/lib/SIL/IR/SILBasicBlock.cpp
@@ -151,25 +151,6 @@ void SILBasicBlock::removeDeadBlock() {
   eraseFromParent();
 }
 
-void SILBasicBlock::cloneArgumentList(SILBasicBlock *Other) {
-  assert(Other->isEntry() == isEntry() &&
-         "Expected to both blocks to be entries or not");
-  if (isEntry()) {
-    assert(args_empty() && "Expected to have no arguments");
-    for (auto *FuncArg : Other->getSILFunctionArguments()) {
-      auto *NewArg =
-          createFunctionArgument(FuncArg->getType(), FuncArg->getDecl());
-      NewArg->copyFlags(FuncArg);
-    }
-    return;
-  }
-
-  for (auto *PHIArg : Other->getSILPhiArguments()) {
-    createPhiArgument(PHIArg->getType(), PHIArg->getOwnershipKind(),
-                      PHIArg->getDecl());
-  }
-}
-
 void SILBasicBlock::moveArgumentList(SILBasicBlock *from) {
   ArgumentList = std::move(from->ArgumentList);
   for (SILArgument *arg : getArguments()) {
@@ -388,7 +369,7 @@ ScopeCloner::ScopeCloner(SILFunction &NewFn) : NewFn(NewFn) {
   // debug scope. Create a new one here.
   // FIXME: Audit all call sites and make them create the function
   // debug scope.
-  auto *SILFn = NewFn.getDebugScope()->Parent.get<SILFunction *>();
+  auto *SILFn = cast<SILFunction *>(NewFn.getDebugScope()->Parent);
   if (SILFn != &NewFn) {
     SILFn->setInlined();
     NewFn.setDebugScope(getOrCreateClonedScope(NewFn.getDebugScope()));
diff --git a/lib/SIL/IR/SILBuilder.cpp b/lib/SIL/IR/SILBuilder.cpp
index 51253dbf76e9e..1f119403299c1 100644
--- a/lib/SIL/IR/SILBuilder.cpp
+++ b/lib/SIL/IR/SILBuilder.cpp
@@ -780,7 +780,7 @@ SwitchEnumInst *SILBuilder::createSwitchEnum(
 
 CheckedCastBranchInst *SILBuilder::createCheckedCastBranch(
     SILLocation Loc, bool isExact,
-    CastingIsolatedConformances isolatedConformances,
+    CheckedCastInstOptions options,
     SILValue op, CanType srcFormalTy,
     SILType destLoweredTy, CanType destFormalTy, SILBasicBlock *successBB,
     SILBasicBlock *failureBB, ProfileCounter target1Count,
@@ -788,14 +788,14 @@ CheckedCastBranchInst *SILBuilder::createCheckedCastBranch(
   auto forwardingOwnership =
       deriveForwardingOwnership(op, destLoweredTy, getFunction());
   return createCheckedCastBranch(
-      Loc, isExact, isolatedConformances, op, srcFormalTy, destLoweredTy,
+      Loc, isExact, options, op, srcFormalTy, destLoweredTy,
       destFormalTy, successBB,
       failureBB, forwardingOwnership, target1Count, target2Count);
 }
 
 CheckedCastBranchInst *SILBuilder::createCheckedCastBranch(
     SILLocation Loc, bool isExact,
-    CastingIsolatedConformances isolatedConformances,
+    CheckedCastInstOptions options,
     SILValue op, CanType srcFormalTy,
     SILType destLoweredTy, CanType destFormalTy, SILBasicBlock *successBB,
     SILBasicBlock *failureBB, ValueOwnershipKind forwardingOwnershipKind,
@@ -805,7 +805,7 @@ CheckedCastBranchInst *SILBuilder::createCheckedCastBranch(
          "failureBB's argument doesn't match incoming argument type");
 
   return insertTerminator(CheckedCastBranchInst::create(
-      getSILDebugLocation(Loc), isExact, isolatedConformances, op, srcFormalTy,
+      getSILDebugLocation(Loc), isExact, options, op, srcFormalTy,
       destLoweredTy, destFormalTy, successBB, failureBB, getFunction(),
       target1Count, target2Count, forwardingOwnershipKind));
 }
diff --git a/lib/SIL/IR/SILConstants.cpp b/lib/SIL/IR/SILConstants.cpp
index 3996a1c3694c4..7005fd7e2965b 100644
--- a/lib/SIL/IR/SILConstants.cpp
+++ b/lib/SIL/IR/SILConstants.cpp
@@ -455,7 +455,7 @@ struct AggregateSymbolicValue final
     auto *aggregate =
         ::new (rawMem) AggregateSymbolicValue(aggregateType, members.size());
     std::uninitialized_copy(members.begin(), members.end(),
-                            aggregate->getTrailingObjects<SymbolicValue>());
+                            aggregate->getTrailingObjects());
     return aggregate;
   }
 
@@ -464,7 +464,7 @@ struct AggregateSymbolicValue final
 
   /// Return the symbolic values of members.
   ArrayRef<SymbolicValue> getMemberValues() const {
-    return {getTrailingObjects<SymbolicValue>(), numElements};
+    return getTrailingObjects(numElements);
   }
 
   // This is used by the llvm::TrailingObjects base class.
@@ -531,12 +531,12 @@ struct alignas(SourceLoc) UnknownSymbolicValue final
     auto value = ::new (rawMem) UnknownSymbolicValue(
         node, reason, static_cast<unsigned>(elements.size()));
     std::uninitialized_copy(elements.begin(), elements.end(),
-                            value->getTrailingObjects<SourceLoc>());
+                            value->getTrailingObjects());
     return value;
   }
 
   ArrayRef<SourceLoc> getCallStack() const {
-    return {getTrailingObjects<SourceLoc>(), callStackSize};
+    return getTrailingObjects(callStackSize);
   }
 
   // This is used by the llvm::TrailingObjects base class.
@@ -657,14 +657,14 @@ struct DerivedAddressValue final
     auto dav =
         ::new (rawMem) DerivedAddressValue(memoryObject, elements.size());
     std::uninitialized_copy(elements.begin(), elements.end(),
-                            dav->getTrailingObjects<unsigned>());
+                            dav->getTrailingObjects());
     return dav;
   }
 
   /// Return the access path for this derived address, which is an array of
   /// indices drilling into the memory object.
   ArrayRef<unsigned> getElements() const {
-    return {getTrailingObjects<unsigned>(), numElements};
+    return getTrailingObjects(numElements);
   }
 
   // This is used by the llvm::TrailingObjects base class.
@@ -749,13 +749,13 @@ struct SymbolicArrayStorage final
     auto *storage =
         ::new (rawMem) SymbolicArrayStorage(elementType, elements.size());
     std::uninitialized_copy(elements.begin(), elements.end(),
-                            storage->getTrailingObjects<SymbolicValue>());
+                            storage->getTrailingObjects());
     return storage;
   }
 
   /// Return the stored elements.
   ArrayRef<SymbolicValue> getElements() const {
-    return {getTrailingObjects<SymbolicValue>(), numElements};
+    return getTrailingObjects(numElements);
   }
 
   // This is used by the llvm::TrailingObjects base class.
@@ -872,9 +872,8 @@ SymbolicClosure *SymbolicClosure::create(SILFunction *target,
   //  Placement initialize the object.
   auto closure = ::new (rawMem) SymbolicClosure(
       target, args.size(), substMap, closureInst, hasNonConstantCapture);
-  std::uninitialized_copy(
-      args.begin(), args.end(),
-      closure->getTrailingObjects<SymbolicClosureArgument>());
+  std::uninitialized_copy(args.begin(), args.end(),
+                          closure->getTrailingObjects());
   return closure;
 }
 
diff --git a/lib/SIL/IR/SILDebugScope.cpp b/lib/SIL/IR/SILDebugScope.cpp
index 5a10c60fc315a..78468183f896d 100644
--- a/lib/SIL/IR/SILDebugScope.cpp
+++ b/lib/SIL/IR/SILDebugScope.cpp
@@ -43,10 +43,10 @@ SILFunction *SILDebugScope::getInlinedFunction() const {
     return nullptr;
 
   const SILDebugScope *Scope = this;
-  while (Scope->Parent.is<const SILDebugScope *>())
-    Scope = Scope->Parent.get<const SILDebugScope *>();
-  assert(Scope->Parent.is<SILFunction *>() && "orphaned scope");
-  return Scope->Parent.get<SILFunction *>();
+  while (isa<const SILDebugScope *>(Scope->Parent))
+    Scope = cast<const SILDebugScope *>(Scope->Parent);
+  assert(isa<SILFunction *>(Scope->Parent) && "orphaned scope");
+  return cast<SILFunction *>(Scope->Parent);
 }
 
 SILFunction *SILDebugScope::getParentFunction() const {
@@ -54,7 +54,7 @@ SILFunction *SILDebugScope::getParentFunction() const {
     return InlinedCallSite->getParentFunction();
   if (auto *ParentScope = Parent.dyn_cast<const SILDebugScope *>())
     return ParentScope->getParentFunction();
-  return Parent.get<SILFunction *>();
+  return cast<SILFunction *>(Parent);
 }
 
 /// Determine whether an instruction may not have a SILDebugScope.
diff --git a/lib/SIL/IR/SILDeclRef.cpp b/lib/SIL/IR/SILDeclRef.cpp
index c8c714fef2149..592f05e988b25 100644
--- a/lib/SIL/IR/SILDeclRef.cpp
+++ b/lib/SIL/IR/SILDeclRef.cpp
@@ -303,6 +303,7 @@ bool SILDeclRef::hasUserWrittenCode() const {
   // Non-implicit decls generally have user-written code.
   if (!isImplicit()) {
     switch (kind) {
+    case Kind::PropertyWrappedFieldInitAccessor:
     case Kind::PropertyWrapperBackingInitializer: {
       // Only has user-written code if any of the property wrappers have
       // arguments to apply. Otherwise, it's just a forwarding initializer for
@@ -386,6 +387,7 @@ bool SILDeclRef::hasUserWrittenCode() const {
   case Kind::IVarInitializer:
   case Kind::IVarDestroyer:
   case Kind::PropertyWrapperBackingInitializer:
+  case Kind::PropertyWrappedFieldInitAccessor:
   case Kind::PropertyWrapperInitFromProjectedValue:
   case Kind::EntryPoint:
   case Kind::AsyncEntryPoint:
@@ -521,6 +523,7 @@ static LinkageLimit getLinkageLimit(SILDeclRef constant) {
     return constant.isSerialized() ? Limit::AlwaysEmitIntoClient : Limit::None;
 
   case Kind::PropertyWrapperBackingInitializer:
+  case Kind::PropertyWrappedFieldInitAccessor:
   case Kind::PropertyWrapperInitFromProjectedValue: {
     if (!d->getDeclContext()->isTypeContext()) {
       // If the backing initializer is to be serialized, only use non-ABI public
@@ -571,6 +574,7 @@ static LinkageLimit getLinkageLimit(SILDeclRef constant) {
   case Kind::AsyncEntryPoint:
     llvm_unreachable("Already handled");
   }
+
   return Limit::None;
 }
 
@@ -751,17 +755,17 @@ SILDeclRef SILDeclRef::getMainFileEntryPoint(FileUnit *file) {
 }
 
 bool SILDeclRef::hasClosureExpr() const {
-  return loc.is<AbstractClosureExpr *>()
-    && isa<ClosureExpr>(getAbstractClosureExpr());
+  return isa<AbstractClosureExpr *>(loc) &&
+         isa<ClosureExpr>(getAbstractClosureExpr());
 }
 
 bool SILDeclRef::hasAutoClosureExpr() const {
-  return loc.is<AbstractClosureExpr *>()
-    && isa<AutoClosureExpr>(getAbstractClosureExpr());
+  return isa<AbstractClosureExpr *>(loc) &&
+         isa<AutoClosureExpr>(getAbstractClosureExpr());
 }
 
 bool SILDeclRef::hasFuncDecl() const {
-  return loc.is<ValueDecl *>() && isa<FuncDecl>(getDecl());
+  return isa<ValueDecl *>(loc) && isa<FuncDecl>(getDecl());
 }
 
 ClosureExpr *SILDeclRef::getClosureExpr() const {
@@ -800,16 +804,31 @@ AbstractFunctionDecl *SILDeclRef::getAbstractFunctionDecl() const {
   return dyn_cast_or_null<AbstractFunctionDecl>(getDecl());
 }
 
-bool SILDeclRef::isInitAccessor() const {
+AccessorDecl *SILDeclRef::getAccessorDecl() const {
   if (kind != Kind::Func || !hasDecl())
-    return false;
+    return nullptr;
+  return dyn_cast_or_null<AccessorDecl>(getDecl());
+}
 
-  if (auto accessor = dyn_cast<AccessorDecl>(getDecl()))
+bool SILDeclRef::isInitAccessor() const {
+  if (auto *accessor = getAccessorDecl())
     return accessor->getAccessorKind() == AccessorKind::Init;
 
   return false;
 }
 
+bool SILDeclRef::isMutateAccessor() const {
+  if (auto *accessor = getAccessorDecl())
+    return accessor->getAccessorKind() == AccessorKind::Mutate;
+  return false;
+}
+
+bool SILDeclRef::isBorrowAccessor() const {
+  if (auto *accessor = getAccessorDecl())
+    return accessor->getAccessorKind() == AccessorKind::Borrow;
+  return false;
+}
+
 /// True if the function should be treated as transparent.
 bool SILDeclRef::isTransparent() const {
   if (isEnumElement())
@@ -883,6 +902,14 @@ SerializedKind_t SILDeclRef::getSerializedKind() const {
 
   auto *d = getDecl();
 
+  ASSERT(ABIRoleInfo(d).providesAPI()
+            && "should not get serialization info from ABI-only decl");
+
+  // A declaration marked as "never emitted into client" will not have its SIL
+  // serialized, ever.
+  if (d->isNeverEmittedIntoClient())
+    return IsNotSerialized;
+
   // Default and property wrapper argument generators are serialized if the
   // containing declaration is public.
   if (isDefaultArgGenerator() || (isPropertyWrapperBackingInitializer() &&
@@ -1021,6 +1048,9 @@ bool SILDeclRef::isNoinline() const {
     return false;
 
   auto *decl = getDecl();
+  ASSERT(ABIRoleInfo(decl).providesAPI()
+            && "should not get inline attr from ABI-only decl");
+
   if (auto *attr = decl->getAttrs().getAttribute<InlineAttr>())
     if (attr->getKind() == InlineKind::Never)
       return true;
@@ -1035,13 +1065,13 @@ bool SILDeclRef::isNoinline() const {
   return false;
 }
 
-/// True if the function has the @inline(__always) attribute.
+/// True if the function has the @inline(always) attribute.
 bool SILDeclRef::isAlwaysInline() const {
   swift::Decl *decl = nullptr;
   if (hasDecl()) {
     decl = getDecl();
   } else if (auto *ce = getAbstractClosureExpr()) {
-    // Closures within @inline(__always) functions should be always inlined, too.
+    // Closures within @inline(always) functions should be always inlined, too.
     // Note that this is different from @inline(never), because closures inside
     // @inline(never) _can_ be inlined within the inline-never function.
     decl = ce->getParent()->getInnermostDeclarationDeclContext();
@@ -1051,6 +1081,9 @@ bool SILDeclRef::isAlwaysInline() const {
     return false;
   }
 
+  ASSERT(ABIRoleInfo(decl).providesAPI()
+            && "should not get inline attr from ABI-only decl");
+
   if (auto attr = decl->getAttrs().getAttribute<InlineAttr>())
     if (attr->getKind() == InlineKind::Always)
       return true;
@@ -1065,17 +1098,133 @@ bool SILDeclRef::isAlwaysInline() const {
   return false;
 }
 
+/// True if the function has the @inline(__always) attribute.
+bool SILDeclRef::isUnderscoredAlwaysInline() const {
+  swift::Decl *decl = nullptr;
+  if (hasDecl()) {
+    decl = getDecl();
+  } else if (auto *ce = getAbstractClosureExpr()) {
+    // Closures within @inline(__always) functions should be always inlined, too.
+    // Note that this is different from @inline(never), because closures inside
+    // @inline(never) _can_ be inlined within the inline-never function.
+    decl = ce->getParent()->getInnermostDeclarationDeclContext();
+    if (!decl)
+      return false;
+  } else {
+    return false;
+  }
+
+  ASSERT(ABIRoleInfo(decl).providesAPI()
+            && "should not get inline attr from ABI-only decl");
+
+  if (auto attr = decl->getAttrs().getAttribute<InlineAttr>())
+    if (attr->getKind() == InlineKind::AlwaysUnderscored)
+      return true;
+
+  if (auto *accessorDecl = dyn_cast<AccessorDecl>(decl)) {
+    auto *storage = accessorDecl->getStorage();
+    if (auto *attr = storage->getAttrs().getAttribute<InlineAttr>())
+      if (attr->getKind() == InlineKind::AlwaysUnderscored)
+        return true;
+  }
+
+  return false;
+}
+
 bool SILDeclRef::isBackDeployed() const {
   if (!hasDecl())
     return false;
 
   auto *decl = getDecl();
+
+  ASSERT(ABIRoleInfo(decl).providesAPI()
+            && "should not get backDeployed from ABI-only decl");
+
   if (auto afd = dyn_cast<AbstractFunctionDecl>(decl))
-    return afd->isBackDeployed(getASTContext());
+    return afd->isBackDeployed();
+
+  return false;
+}
+
+bool SILDeclRef::hasNonUniqueDefinition() const {
+  if (auto decl = getDecl())
+    return declHasNonUniqueDefinition(decl);
+
+  return false;
+}
+
+bool SILDeclRef::declExposedToForeignLanguage(const ValueDecl *decl) {
+  // @c / @_cdecl / @objc.
+  if (decl->getAttrs().hasAttribute<CDeclAttr>() ||
+      (decl->getAttrs().hasAttribute<ObjCAttr>() &&
+       decl->getDeclContext()->isModuleScopeContext())) {
+    return true;
+  }
+
+  // @_expose that isn't negated.
+  for (auto *expose : decl->getAttrs().getAttributes<ExposeAttr>()) {
+    switch (expose->getExposureKind()) {
+      case ExposureKind::Cxx:
+      case ExposureKind::Wasm:
+        return true;
+
+      case ExposureKind::NotCxx:
+        continue;
+    }
+  }
 
   return false;
 }
 
+bool SILDeclRef::declHasNonUniqueDefinition(const ValueDecl *decl) {
+  // This function only forces the issue in embedded.
+  if (!decl->getASTContext().LangOpts.hasFeature(Feature::Embedded))
+    return false;
+
+  // If the declaration is marked as @_neverEmitIntoClient, it has a unique
+  // definition.
+  if (decl->isNeverEmittedIntoClient())
+    return false;
+
+  /// @_alwaysEmitIntoClient means that we have a non-unique definition.
+  if (decl->getAttrs().hasAttribute<AlwaysEmitIntoClientAttr>())
+    return true;
+
+  // If the declaration is marked in a manner that indicates that other
+  // systems will expect it to have a symbol, then it has a unique definition.
+  // There are a few cases here.
+
+  // - @implementation explicitly says that we are implementing something to
+  // be called from another language, so call it non-unique.
+  if (decl->isObjCImplementation())
+    return false;
+
+  // - @c / @_cdecl / @objc / @_expose expect to be called from another
+  // language if the symbol itself would be visible.
+  if (declExposedToForeignLanguage(decl) &&
+      decl->getFormalAccess() >= AccessLevel::Internal) {
+    return false;
+  }
+
+  // - @_section and @_used imply that external tools will look for this symbol.
+  if (decl->getAttrs().hasAttribute<SectionAttr>() ||
+      decl->getAttrs().hasAttribute<UsedAttr>()) {
+    return false;
+  }
+
+  auto module = decl->getModuleContext();
+  auto &ctx = module->getASTContext();
+
+  /// With deferred code generation, declarations are emitted as late as
+  /// possible, so they must have non-unique definitions.
+  if (module->deferredCodeGen())
+    return true;
+
+  // If the declaration is not from the main module, treat its definition as
+  // non-unique.
+  return module != ctx.MainModule && ctx.MainModule;
+}
+
 bool SILDeclRef::isForeignToNativeThunk() const {
   // If this isn't a native entry-point, it's not a foreign-to-native thunk.
   if (isForeign)
@@ -1198,6 +1347,9 @@ static std::string mangleClangDecl(Decl *decl, bool isForeign) {
 }
 
 std::string SILDeclRef::mangle(ManglingKind MKind) const {
+  ASSERT(!hasDecl() || ABIRoleInfo(getDecl()).providesAPI()
+            && "SILDeclRef mangling ABI decl directly?");
+
   using namespace Mangle;
   ASTMangler mangler(getASTContext());
 
@@ -1268,9 +1420,6 @@ std::string SILDeclRef::mangle(ManglingKind MKind) const {
     if (auto *ACE = getAbstractClosureExpr())
       return mangler.mangleClosureEntity(ACE, SKind);
 
-    ASSERT(ABIRoleInfo(getDecl()).providesAPI()
-              && "SILDeclRef mangling ABI decl directly?");
-
     // As a special case, functions can have manually mangled names.
     // Use the SILGen name only for the original non-thunked, non-curried entry
     // point.
@@ -1285,7 +1434,7 @@ std::string SILDeclRef::mangle(ManglingKind MKind) const {
     }
 
     // Use a given cdecl name for native-to-foreign thunks.
-    if (auto CDeclA = getDecl()->getAttrs().getAttribute<CDeclAttr>())
+    if (getDecl()->getAttrs().hasAttribute<CDeclAttr>())
       if (isNativeToForeignThunk()) {
         // If this is an @implementation @_cdecl, mangle it like the clang
         // function it implements.
@@ -1294,7 +1443,7 @@ std::string SILDeclRef::mangle(ManglingKind MKind) const {
           if (!clangMangling.empty())
             return clangMangling;
         }
-        return CDeclA->Name.str();
+        return getDecl()->getCDeclName().str();
       }
 
     if (SKind == ASTMangler::SymbolKind::DistributedThunk) {
@@ -1365,6 +1514,10 @@ std::string SILDeclRef::mangle(ManglingKind MKind) const {
     return mangler.mangleBackingInitializerEntity(cast<VarDecl>(getDecl()),
                                                   SKind);
 
+  case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
+    return mangler.manglePropertyWrappedFieldInitAccessorEntity(
+        cast<VarDecl>(getDecl()), SKind);
+
   case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
     return mangler.mangleInitFromProjectedValueEntity(cast<VarDecl>(getDecl()),
                                                       SKind);
@@ -1720,6 +1873,7 @@ Expr *SILDeclRef::getInitializationExpr() const {
     }
     return init;
   }
+  case Kind::PropertyWrappedFieldInitAccessor:
   case Kind::PropertyWrapperBackingInitializer: {
     auto *var = cast<VarDecl>(getDecl());
     auto wrapperInfo = var->getPropertyWrapperInitializerInfo();
@@ -1855,5 +2009,26 @@ bool SILDeclRef::isCalleeAllocatedCoroutine() const {
   if (!accessor)
     return false;
 
-  return requiresFeatureCoroutineAccessors(accessor->getAccessorKind());
+  if (!requiresFeatureCoroutineAccessors(accessor->getAccessorKind()))
+    return false;
+
+  return getASTContext().SILOpts.CoroutineAccessorsUseYieldOnce2;
+}
+
+ActorIsolation SILDeclRef::getActorIsolation() const {
+  // Deallocating destructor is always nonisolated. Isolation of the deinit
+  // applies only to isolated deallocator and destroyer.
+  if (kind == SILDeclRef::Kind::Deallocator) {
+    return ActorIsolation::forNonisolated(false);
+  }
+
+  // Default argument generators use the isolation of the initializer,
+  // not the general isolation of the function.
+  if (isDefaultArgGenerator()) {
+    auto param = getParameterAt(getDecl(), defaultArgIndex);
+    assert(param);
+    return param->getInitializerIsolation();
+  }
+
+  return getActorIsolationOfContext(getInnermostDeclContext());
 }
diff --git a/lib/SIL/IR/SILFunction.cpp b/lib/SIL/IR/SILFunction.cpp
index 57cb2f36a118c..bf1d41eaf903a 100644
--- a/lib/SIL/IR/SILFunction.cpp
+++ b/lib/SIL/IR/SILFunction.cpp
@@ -214,6 +214,7 @@ static BridgedFunction::CopyEffectsFn copyEffectsFunction = nullptr;
 static BridgedFunction::GetEffectInfoFn getEffectInfoFunction = nullptr;
 static BridgedFunction::GetMemBehaviorFn getMemBehvaiorFunction = nullptr;
 static BridgedFunction::ArgumentMayReadFn argumentMayReadFunction = nullptr;
+static BridgedFunction::IsDeinitBarrierFn isDeinitBarrierFunction = nullptr;
 
 SILFunction::SILFunction(
     SILModule &Module, SILLinkage Linkage, StringRef Name,
@@ -552,6 +553,28 @@ bool SILFunction::isNoReturnFunction(TypeExpansionContext context) const {
       .isNoReturnFunction(getModule(), context);
 }
 
+bool SILFunction::hasNonUniqueDefinition() const {
+  // Non-uniqueness is a property of the Embedded linkage model.
+  if (!getASTContext().LangOpts.hasFeature(Feature::Embedded))
+    return false;
+
+  // If this function is the entrypoint, it is unique.
+  if (getName() == getASTContext().getEntryPointFunctionName())
+    return false;
+
+  // If this is for a declaration, ask it.
+  if (auto declRef = getDeclRef()) {
+    return declRef.hasNonUniqueDefinition();
+  }
+
+  // If this function is from a different module than the one we are emitting
+  // code for, then it must have a non-unique definition.
+  if (getParentModule() != getModule().getSwiftModule())
+    return true;
+
+  return false;
+}
+
 ResilienceExpansion SILFunction::getResilienceExpansion() const {
   // If a function definition is in another module, and
   // it was serialized due to package serialization opt,
@@ -565,8 +588,24 @@ ResilienceExpansion SILFunction::getResilienceExpansion() const {
           : ResilienceExpansion::Maximal);
 }
 
+SILTypeProperties
+SILFunction::getTypeProperties(AbstractionPattern orig, Type subst) const {
+  return getModule().Types.getTypeProperties(orig, subst,
+                                             TypeExpansionContext(*this));
+}
+
+SILTypeProperties SILFunction::getTypeProperties(Type subst) const {
+  return getModule().Types.getTypeProperties(subst,
+                                             TypeExpansionContext(*this));
+}
+
+SILTypeProperties SILFunction::getTypeProperties(SILType type) const {
+  return getModule().Types.getTypeProperties(type,
+                                             TypeExpansionContext(*this));
+}
+
 const TypeLowering &
-SILFunction::getTypeLowering(AbstractionPattern orig, Type subst) {
+SILFunction::getTypeLowering(AbstractionPattern orig, Type subst) const {
   return getModule().Types.getTypeLowering(orig, subst,
                                            TypeExpansionContext(*this));
 }
@@ -618,7 +657,8 @@ bool SILFunction::isWeakImported(ModuleDecl *module) const {
 
   // For imported functions check the Clang declaration.
   if (ClangNodeOwner)
-    return ClangNodeOwner->getClangDecl()->isWeakImported();
+    return ClangNodeOwner->getClangDecl()->isWeakImported(
+        getASTContext().LangOpts.getMinPlatformVersion());
 
   // For native functions check a flag on the SILFunction
   // itself.
@@ -998,6 +1038,20 @@ bool SILFunction::hasValidLinkageForFragileRef(SerializedKind_t callerSerialized
   return hasPublicOrPackageVisibility(getLinkage(), /*includePackage*/ true);
 }
 
+bool SILFunction::isSwiftRuntimeFunction(
+    StringRef name, const ModuleDecl *module) {
+  if (!name.starts_with("swift_") && !name.starts_with("_swift_"))
+    return false;
+
+  return !module ||
+      module->getName().str() == "Swift" ||
+      module->getName().str() == "_Concurrency";
+}
+
+bool SILFunction::isSwiftRuntimeFunction() const {
+  return isSwiftRuntimeFunction(getName(), getParentModule());
+}
+
 bool
 SILFunction::isPossiblyUsedExternally() const {
   auto linkage = getLinkage();
@@ -1018,6 +1072,18 @@ SILFunction::isPossiblyUsedExternally() const {
   if (markedAsUsed())
     return true;
 
+  // If this function is exposed to a foreign language, it can be used
+  // externally (by that language).
+  if (auto decl = getDeclRef().getDecl()) {
+    if (SILDeclRef::declExposedToForeignLanguage(decl))
+      return true;
+  }
+
+  // If this function was explicitly placed in a section or given a WebAssembly
+  // export, it can be used externally.
+  if (!Section.empty() || !WasmExportName.empty())
+    return true;
+
   if (shouldBePreservedForDebugger())
     return true;
 
@@ -1028,6 +1094,11 @@ SILFunction::isPossiblyUsedExternally() const {
       hasOpaqueResultTypeWithAvailabilityConditions())
     return true;
 
+  // All Swift runtime functions can be used externally.
+  if (getASTContext().LangOpts.hasFeature(Feature::Embedded) &&
+      isSwiftRuntimeFunction())
+    return true;
+
   return swift::isPossiblyUsedExternally(linkage, getModule().isWholeModule());
 }
 
@@ -1175,7 +1246,8 @@ void BridgedFunction::registerBridging(SwiftMetatype metatype,
             CopyEffectsFn copyEffectsFn,
             GetEffectInfoFn effectInfoFn,
             GetMemBehaviorFn memBehaviorFn,
-            ArgumentMayReadFn argumentMayReadFn) {
+            ArgumentMayReadFn argumentMayReadFn,
+            IsDeinitBarrierFn isDeinitBarrierFn) {
   functionMetatype = metatype;
   initFunction = initFn;
   destroyFunction = destroyFn;
@@ -1185,6 +1257,7 @@ void BridgedFunction::registerBridging(SwiftMetatype metatype,
   getEffectInfoFunction = effectInfoFn;
   getMemBehvaiorFunction = memBehaviorFn;
   argumentMayReadFunction = argumentMayReadFn;
+  isDeinitBarrierFunction = isDeinitBarrierFn;
 }
 
 std::pair<const char *, int>  SILFunction::
@@ -1286,6 +1359,13 @@ bool SILFunction::argumentMayRead(Operand *argOp, SILValue addr) {
   return argumentMayReadFunction({this}, {argOp}, {addr});
 }
 
+bool SILFunction::isDeinitBarrier() {
+  if (!isDeinitBarrierFunction)
+    return true;
+
+  return isDeinitBarrierFunction({this});
+}
+
 SourceFile *SILFunction::getSourceFile() const {
   auto declRef = getDeclRef();
   if (!declRef)
diff --git a/lib/SIL/IR/SILFunctionBuilder.cpp b/lib/SIL/IR/SILFunctionBuilder.cpp
index b15f75b4645c8..b6bea9951cb72 100644
--- a/lib/SIL/IR/SILFunctionBuilder.cpp
+++ b/lib/SIL/IR/SILFunctionBuilder.cpp
@@ -61,12 +61,13 @@ void SILFunctionBuilder::addFunctionAttributes(
   // function as force emitting all optremarks including assembly vision
   // remarks. This allows us to emit the assembly vision remarks without needing
   // to change any of the underlying optremark mechanisms.
-  if (Attrs.getAttribute(DeclAttrKind::EmitAssemblyVisionRemarks))
+  if (Attrs.getAttribute(DeclAttrKind::EmitAssemblyVisionRemarks) ||
+      M.getOptions().EnableGlobalAssemblyVision)
     F->addSemanticsAttr(semantics::FORCE_EMIT_OPT_REMARK_PREFIX);
 
   // Propagate @_specialize.
-  for (auto *A : Attrs.getAttributes<SpecializeAttr>()) {
-    auto *SA = cast<SpecializeAttr>(A);
+  for (auto *A : Attrs.getAttributes<AbstractSpecializeAttr>()) {
+    auto *SA = cast<AbstractSpecializeAttr>(A);
     auto kind =
         SA->getSpecializationKind() == SpecializeAttr::SpecializationKind::Full
             ? SILSpecializeAttr::SpecializationKind::Full
@@ -169,7 +170,7 @@ void SILFunctionBuilder::addFunctionAttributes(
   for (auto *EA : Attrs.getAttributes<ExposeAttr>()) {
     bool shouldExportDecl = true;
     if (Attrs.hasAttribute<CDeclAttr>()) {
-      // If the function is marked with @cdecl, expose only C compatible
+      // If the function is marked with @c, expose only C compatible
       // thunk function.
       shouldExportDecl = constant.isNativeToForeignThunk();
     }
@@ -202,6 +203,8 @@ void SILFunctionBuilder::addFunctionAttributes(
     F->setPerfConstraints(PerformanceConstraints::NoExistentials);
   } else if (Attrs.hasAttribute<NoObjCBridgingAttr>()) {
     F->setPerfConstraints(PerformanceConstraints::NoObjCBridging);
+  } else if (Attrs.hasAttribute<ManualOwnershipAttr>()) {
+    F->setPerfConstraints(PerformanceConstraints::ManualOwnership);
   }
 
   if (Attrs.hasAttribute<LexicalLifetimesAttr>()) {
@@ -334,6 +337,8 @@ SILFunction *SILFunctionBuilder::getOrCreateFunction(
   Inline_t inlineStrategy = InlineDefault;
   if (constant.isNoinline())
     inlineStrategy = NoInline;
+  else if (constant.isUnderscoredAlwaysInline())
+    inlineStrategy = HeuristicAlwaysInline;
   else if (constant.isAlwaysInline())
     inlineStrategy = AlwaysInline;
 
diff --git a/lib/SIL/IR/SILFunctionType.cpp b/lib/SIL/IR/SILFunctionType.cpp
index db4723b6818ae..d7981cc106d0e 100644
--- a/lib/SIL/IR/SILFunctionType.cpp
+++ b/lib/SIL/IR/SILFunctionType.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -16,10 +16,11 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "swift/AST/Expr.h"
+#include "swift/AST/Type.h"
 #define DEBUG_TYPE "libsil"
 
 #include "swift/AST/AnyFunctionRef.h"
-#include "swift/AST/CanTypeVisitor.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/DiagnosticsSIL.h"
 #include "swift/AST/ForeignInfo.h"
@@ -59,12 +60,10 @@ SILType SILFunctionType::substInterfaceType(SILModule &M,
   return interfaceType;
 }
 
-SILFunctionType::ExtInfo
-SILFunctionType::getSubstLifetimeDependencies(GenericSignature genericSig,
-                                              ExtInfo origExtInfo,
-                                              ArrayRef<SILParameterInfo> params,
-                                              ArrayRef<SILYieldInfo> yields,
-                                              ArrayRef<SILResultInfo> results) {
+SILFunctionType::ExtInfo SILFunctionType::getSubstLifetimeDependencies(
+    GenericSignature genericSig, ExtInfo origExtInfo, ASTContext &context,
+    ArrayRef<SILParameterInfo> params, ArrayRef<SILYieldInfo> yields,
+    ArrayRef<SILResultInfo> results) {
   if (origExtInfo.getLifetimeDependencies().empty()) {
     return origExtInfo;
   }
@@ -87,7 +86,8 @@ SILFunctionType::getSubstLifetimeDependencies(GenericSignature genericSig,
       }
     });
   if (didRemoveLifetimeDependencies) {
-    return origExtInfo.withLifetimeDependencies(substLifetimeDependencies);
+    return origExtInfo.withLifetimeDependencies(
+        context.AllocateCopy(substLifetimeDependencies));
   }
   return origExtInfo;
 }
@@ -131,10 +131,10 @@ CanSILFunctionType SILFunctionType::getUnsubstitutedType(SILModule &M) const {
 
   auto signature = isPolymorphic() ? getInvocationGenericSignature()
                                    : CanGenericSignature();
-  
-  auto extInfo = getSubstLifetimeDependencies(signature, getExtInfo(),
-                                              params, yields, results);
-  
+
+  auto extInfo = getSubstLifetimeDependencies(
+      signature, getExtInfo(), getASTContext(), params, yields, results);
+
   return SILFunctionType::get(signature,
                               extInfo,
                               getCoroutineKind(),
@@ -181,6 +181,12 @@ SILType
 SILFunctionType::getDirectFormalResultsType(SILModule &M,
                                             TypeExpansionContext context) {
   CanType type;
+
+  if (hasGuaranteedAddressResult()) {
+    assert(getNumDirectFormalResults() == 1);
+      return SILType::getPrimitiveAddressType(
+          getSingleDirectFormalResult().getReturnValueType(M, this, context));
+  }
   if (getNumDirectFormalResults() == 0) {
     type = getASTContext().TheEmptyTupleType;
   } else if (getNumDirectFormalResults() == 1) {
@@ -538,11 +544,11 @@ static CanSILFunctionType getAutoDiffDifferentialType(
 
     tanType = tanType->getReducedType(sig);
     AbstractionPattern pattern(sig, tanType);
-    auto &tl =
-        TC.getTypeLowering(pattern, tanType, TypeExpansionContext::minimal());
+    auto props =
+        TC.getTypeProperties(pattern, tanType, TypeExpansionContext::minimal());
     // When the tangent type is address only, we must ensure that the tangent
     // parameter's convention is indirect.
-    if (tl.isAddressOnly() && !isIndirectFormalParameter(origParamConv)) {
+    if (props.isAddressOnly() && !isIndirectFormalParameter(origParamConv)) {
       switch (origParamConv) {
       case ParameterConvention::Direct_Guaranteed:
         return ParameterConvention::Indirect_In_Guaranteed;
@@ -566,11 +572,11 @@ static CanSILFunctionType getAutoDiffDifferentialType(
 
     tanType = tanType->getReducedType(sig);
     AbstractionPattern pattern(sig, tanType);
-    auto &tl =
-        TC.getTypeLowering(pattern, tanType, TypeExpansionContext::minimal());
+    auto props =
+        TC.getTypeProperties(pattern, tanType, TypeExpansionContext::minimal());
     // When the tangent type is address only, we must ensure that the tangent
     // result's convention is indirect.
-    if (tl.isAddressOnly() && !isIndirectFormalResult(origResConv)) {
+    if (props.isAddressOnly() && !isIndirectFormalResult(origResConv)) {
       switch (origResConv) {
       case ResultConvention::Unowned:
       case ResultConvention::Owned:
@@ -700,19 +706,19 @@ static CanSILFunctionType getAutoDiffPullbackType(
 
     tanType = tanType->getReducedType(sig);
     AbstractionPattern pattern(sig, tanType);
-    auto &tl =
-        TC.getTypeLowering(pattern, tanType, TypeExpansionContext::minimal());
+    auto props =
+        TC.getTypeProperties(pattern, tanType, TypeExpansionContext::minimal());
     ParameterConvention conv;
     switch (origResConv) {
     case ResultConvention::Unowned:
     case ResultConvention::UnownedInnerPointer:
     case ResultConvention::Owned:
     case ResultConvention::Autoreleased:
-      if (tl.isAddressOnly()) {
+      if (props.isAddressOnly()) {
         conv = ParameterConvention::Indirect_In_Guaranteed;
       } else {
-        conv = tl.isTrivial() ? ParameterConvention::Direct_Unowned
-                              : ParameterConvention::Direct_Guaranteed;
+        conv = props.isTrivial() ? ParameterConvention::Direct_Unowned
+                                 : ParameterConvention::Direct_Guaranteed;
       }
       break;
     case ResultConvention::Pack:
@@ -721,6 +727,9 @@ static CanSILFunctionType getAutoDiffPullbackType(
     case ResultConvention::Indirect:
       conv = ParameterConvention::Indirect_In_Guaranteed;
       break;
+    case ResultConvention::GuaranteedAddress:
+    case ResultConvention::Guaranteed:
+      llvm_unreachable("borrow/mutate accessor not yet implemented");
     }
     return conv;
   };
@@ -734,18 +743,18 @@ static CanSILFunctionType getAutoDiffPullbackType(
 
     tanType = tanType->getReducedType(sig);
     AbstractionPattern pattern(sig, tanType);
-    auto &tl =
-        TC.getTypeLowering(pattern, tanType, TypeExpansionContext::minimal());
+    auto props =
+        TC.getTypeProperties(pattern, tanType, TypeExpansionContext::minimal());
     ResultConvention conv;
     switch (origParamConv) {
     case ParameterConvention::Direct_Owned:
     case ParameterConvention::Direct_Guaranteed:
     case ParameterConvention::Direct_Unowned:
-      if (tl.isAddressOnly()) {
+      if (props.isAddressOnly()) {
         conv = ResultConvention::Indirect;
       } else {
-        conv = tl.isTrivial() ? ResultConvention::Unowned
-                              : ResultConvention::Owned;
+        conv = props.isTrivial() ? ResultConvention::Unowned
+                                 : ResultConvention::Owned;
       }
       break;
     case ParameterConvention::Pack_Owned:
@@ -1049,14 +1058,14 @@ CanSILFunctionType SILFunctionType::getAutoDiffTransposeFunctionType(
   auto getParameterInfoForOriginalResult =
       [&](const SILResultInfo &result) -> SILParameterInfo {
     AbstractionPattern pattern(transposeFnGenSig, result.getInterfaceType());
-    auto &tl = TC.getTypeLowering(pattern, result.getInterfaceType(),
-                                  TypeExpansionContext::minimal());
+    auto props = TC.getTypeProperties(pattern, result.getInterfaceType(),
+                                      TypeExpansionContext::minimal());
     ParameterConvention newConv;
     switch (result.getConvention()) {
     case ResultConvention::Owned:
     case ResultConvention::Autoreleased:
-      newConv = tl.isTrivial() ? ParameterConvention::Direct_Unowned
-                               : ParameterConvention::Direct_Guaranteed;
+      newConv = props.isTrivial() ? ParameterConvention::Direct_Unowned
+                                  : ParameterConvention::Direct_Guaranteed;
       break;
     case ResultConvention::Unowned:
     case ResultConvention::UnownedInnerPointer:
@@ -1068,6 +1077,9 @@ CanSILFunctionType SILFunctionType::getAutoDiffTransposeFunctionType(
     case ResultConvention::Indirect:
       newConv = ParameterConvention::Indirect_In_Guaranteed;
       break;
+    case ResultConvention::GuaranteedAddress:
+    case ResultConvention::Guaranteed:
+      llvm_unreachable("borrow accessor is not yet implemented");
     }
     return {result.getInterfaceType(), newConv};
   };
@@ -1076,15 +1088,15 @@ CanSILFunctionType SILFunctionType::getAutoDiffTransposeFunctionType(
   auto getResultInfoForOriginalParameter =
       [&](const SILParameterInfo &param) -> SILResultInfo {
     AbstractionPattern pattern(transposeFnGenSig, param.getInterfaceType());
-    auto &tl = TC.getTypeLowering(pattern, param.getInterfaceType(),
-                                  TypeExpansionContext::minimal());
+    auto props = TC.getTypeProperties(pattern, param.getInterfaceType(),
+                                      TypeExpansionContext::minimal());
     ResultConvention newConv;
     switch (param.getConvention()) {
     case ParameterConvention::Direct_Owned:
     case ParameterConvention::Direct_Guaranteed:
     case ParameterConvention::Direct_Unowned:
       newConv =
-          tl.isTrivial() ? ResultConvention::Unowned : ResultConvention::Owned;
+          props.isTrivial() ? ResultConvention::Unowned : ResultConvention::Owned;
       break;
     case ParameterConvention::Pack_Owned:
     case ParameterConvention::Pack_Guaranteed:
@@ -1263,6 +1275,11 @@ class Conventions {
 
   ConventionsKind getKind() const { return kind; }
 
+  bool hasCallerIsolationParameter() const {
+    return kind == ConventionsKind::Default ||
+           kind == ConventionsKind::Deallocator;
+  }
+
   virtual ParameterConvention
   getIndirectParameter(unsigned index,
                        const AbstractionPattern &type,
@@ -1345,26 +1362,37 @@ class Conventions {
     llvm_unreachable("unhandled ownership");
   }
 
-  // Determines owned/unowned ResultConvention of the returned value based on
-  // returns_retained/returns_unretained attribute.
+  // Determines the ownership ResultConvention (owned/unowned) of the return
+  // value using the SWIFT_RETURNS_(UN)RETAINED annotation on the C++ API; if
+  // not explicitly annotated, falls back to the
+  // SWIFT_RETURNED_AS_(UN)RETAINED_BY_DEFAULT annotation on the C++
+  // SWIFT_SHARED_REFERENCE type.
   std::optional<ResultConvention>
   getCxxRefConventionWithAttrs(const TypeLowering &tl,
                                const clang::Decl *decl) const {
-    if (tl.getLoweredType().isForeignReferenceType() && decl->hasAttrs()) {
-      for (const auto *attr : decl->getAttrs()) {
-        if (const auto *swiftAttr = dyn_cast<clang::SwiftAttrAttr>(attr)) {
-          if (swiftAttr->getAttribute() == "returns_unretained") {
-            return ResultConvention::Unowned;
-          } else if (swiftAttr->getAttribute() == "returns_retained") {
-            return ResultConvention::Owned;
-          }
-        }
-      }
-    }
-    return std::nullopt;
+    if (!tl.getLoweredType().isForeignReferenceType())
+      return std::nullopt;
+
+    return importer::getCxxRefConventionWithAttrs(decl);
   }
 };
 
+static bool isBorrowAccessor(std::optional<SILDeclRef> constant) {
+  if (!constant || !constant->hasDecl())
+    return false;
+
+  auto accessor = dyn_cast<AccessorDecl>(constant->getDecl());
+  return accessor && accessor->isBorrowAccessor();
+}
+
+static bool isMutateAccessor(std::optional<SILDeclRef> constant) {
+  if (!constant || !constant->hasDecl())
+    return false;
+
+  auto accessor = dyn_cast<AccessorDecl>(constant->getDecl());
+  return accessor && accessor->isMutateAccessor();
+}
+
 /// A visitor for breaking down formal result types into a SILResultInfo
 /// and possibly some number of indirect-out SILParameterInfos,
 /// matching the abstraction patterns of the original type.
@@ -1374,18 +1402,21 @@ class DestructureResults {
   SmallVectorImpl<SILResultInfo> &Results;
   TypeExpansionContext context;
   bool hasSendingResult;
+  std::optional<SILDeclRef> constant;
 
 public:
   DestructureResults(TypeExpansionContext context, TypeConverter &TC,
                      const Conventions &conventions,
                      SmallVectorImpl<SILResultInfo> &results,
-                     bool hasSendingResult)
+                     bool hasSendingResult, std::optional<SILDeclRef> constant)
       : TC(TC), Convs(conventions), Results(results), context(context),
-        hasSendingResult(hasSendingResult) {}
+        hasSendingResult(hasSendingResult), constant(constant) {}
 
   void destructure(AbstractionPattern origType, CanType substType) {
     // Recur into tuples.
-    if (origType.isTuple()) {
+    // Do not explode tuples for borrow and mutate accessors since we cannot
+    // explode and reconstruct addresses.
+    if (origType.isTuple() && !isBorrowAccessor(constant)) {
       origType.forEachTupleElement(substType,
                                    [&](TupleElementGenerator &elt) {
         // If the original element type is not a pack expansion, just
@@ -1395,6 +1426,11 @@ class DestructureResults {
           return;
         }
 
+        if (isBorrowAccessor(constant)) {
+          llvm_unreachable(
+              "Returning packs from borrow/mutate accessor is not implemented");
+        }
+
         // If the original element type is a pack expansion, build a
         // lowered pack type for the substituted components it expands to.
         auto origExpansionType = elt.getOrigType();
@@ -1426,8 +1462,20 @@ class DestructureResults {
 
     // Determine the result convention.
     ResultConvention convention;
-    if (isFormallyReturnedIndirectly(origType, substType,
-                                     substResultTLForConvention)) {
+
+    if (isBorrowAccessor(constant)) {
+      if (substResultTL.isTrivial()) {
+        convention = ResultConvention::Unowned;
+      } else if (isFormallyReturnedIndirectly(origType, substType,
+                                              substResultTLForConvention)) {
+        convention = ResultConvention::GuaranteedAddress;
+      } else {
+        convention = ResultConvention::Guaranteed;
+      }
+    } else if (isMutateAccessor(constant)) {
+      convention = ResultConvention::GuaranteedAddress;
+    } else if (isFormallyReturnedIndirectly(origType, substType,
+                                            substResultTLForConvention)) {
       convention = ResultConvention::Indirect;
     } else {
       convention = Convs.getResult(substResultTLForConvention);
@@ -1443,16 +1491,20 @@ class DestructureResults {
 
         case ResultConvention::Pack:
           llvm_unreachable("pack convention for non-pack");
+        case ResultConvention::GuaranteedAddress:
+          llvm_unreachable(
+              "Invalid case of ResultConvention::GuaranteedAddress");
 
         case ResultConvention::Autoreleased:
         case ResultConvention::Owned:
+        case ResultConvention::Guaranteed:
           // These aren't distinguishable from unowned for trivial types.
           convention = ResultConvention::Unowned;
           break;
         }
       }
     }
-    
+
     SILResultInfo result(substResultTL.getLoweredType().getASTType(),
                          convention);
     if (hasSendingResult)
@@ -1520,10 +1572,8 @@ static bool isClangTypeMoreIndirectThanSubstType(TypeConverter &TC,
       return false;
 
     if (clangTy->getPointeeType()->getAs<clang::RecordType>()) {
-      // CF type as foreign class
-      if (substTy->getClassOrBoundGenericClass() &&
-          substTy->getClassOrBoundGenericClass()->getForeignClassKind() ==
-            ClassDecl::ForeignKind::CFType) {
+      // Foreign reference types
+      if (substTy->getClassOrBoundGenericClass()) {
         return false;
       }
     }
@@ -1540,7 +1590,15 @@ static bool isClangTypeMoreIndirectThanSubstType(TypeConverter &TC,
   // Pass C++ const reference types indirectly. Right now there's no way to
   // express immutable borrowed params, so we have to have this hack.
   // Eventually, we should just express these correctly: rdar://89647503
-  if (importer::isCxxConstReferenceType(clangTy))
+  // If this is a const reference to a foreign reference type (const FRT&), this
+  // is equivalent to a pointer to the foreign reference type, which are passed
+  // directly.
+  if (importer::isCxxConstReferenceType(clangTy) &&
+      !(clangTy->getPointeeType()->getAs<clang::RecordType>() &&
+        substTy->isForeignReferenceType()))
+    return true;
+
+  if (clangTy->isRValueReferenceType())
     return true;
 
   return false;
@@ -1701,10 +1759,10 @@ class DestructureInputs {
       };
     }
 
-    // If we are an async function that is unspecified or nonisolated, insert an
-    // isolated parameter if AsyncCallerExecution is enabled.
+    // If the function has nonisolated(nonsending) isolation, insert the
+    // implicit isolation parameter.
     if (IsolationInfo && IsolationInfo->isCallerIsolationInheriting() &&
-        extInfoBuilder.isAsync()) {
+        Convs.hasCallerIsolationParameter()) {
       auto actorProtocol = TC.Context.getProtocol(KnownProtocolKind::Actor);
       auto actorType =
           ExistentialType::get(actorProtocol->getDeclaredInterfaceType());
@@ -1859,8 +1917,7 @@ class DestructureInputs {
       // If there is a scoped dependency on this parameter, and the parameter
       // is addressable-for-dependencies, then lower it with maximal abstraction
       // as well.
-      auto &initialSubstTL = TC.getTypeLowering(origType, substType, expansion);
-      if (initialSubstTL.getRecursiveProperties()
+      if (TC.getTypeProperties(origType, substType, expansion)
           .isAddressableForDependencies()) {
         origType = AbstractionPattern::getOpaque();
 
@@ -2386,6 +2443,43 @@ static void destructureYieldsForCoroutine(TypeConverter &TC,
   }
 }
 
+std::optional<ActorIsolation>
+swift::getSILFunctionTypeActorIsolation(CanAnyFunctionType substFnInterfaceType,
+                                        std::optional<SILDeclRef> origConstant,
+                                        std::optional<SILDeclRef> constant) {
+  // If we have origConstant then we are creating a protocol method thunk. In
+  // such a case, we want to use the origConstant's actor isolation.
+  if (origConstant && constant &&
+      *origConstant != *constant) {
+    if (auto *decl = origConstant->getAbstractFunctionDecl()) {
+      if (auto *nonisolatedAttr =
+              decl->getAttrs().getAttribute<NonisolatedAttr>()) {
+        if (nonisolatedAttr->isNonSending())
+          return ActorIsolation::forCallerIsolationInheriting();
+      }
+
+      if (decl->getAttrs().hasAttribute<ConcurrentAttr>()) {
+        return ActorIsolation::forNonisolated(false /*unsafe*/);
+      }
+    }
+
+    return getActorIsolationOfContext(origConstant->getInnermostDeclContext());
+  }
+
+  if (constant) {
+    return constant->getActorIsolation();
+  }
+
+  if (substFnInterfaceType->hasExtInfo() &&
+      substFnInterfaceType->getExtInfo().getIsolation().isNonIsolatedCaller()) {
+    // If our function type is a nonisolated caller and we can not infer from
+    // our constant, we must be caller isolation inheriting.
+    return ActorIsolation::forCallerIsolationInheriting();
+  }
+
+  return {};
+}
+
 /// Create the appropriate SIL function type for the given formal type
 /// and conventions.
 ///
@@ -2478,8 +2572,10 @@ static CanSILFunctionType getSILFunctionType(
   
   if (auto accessor = getAsCoroutineAccessor(constant)) {
     auto origAccessor = cast<AccessorDecl>(origConstant->getDecl());
+    auto &ctx = origAccessor->getASTContext();
     coroutineKind =
-        requiresFeatureCoroutineAccessors(accessor->getAccessorKind())
+        (requiresFeatureCoroutineAccessors(accessor->getAccessorKind()) &&
+         ctx.SILOpts.CoroutineAccessorsUseYieldOnce2)
             ? SILCoroutineKind::YieldOnce2
             : SILCoroutineKind::YieldOnce;
 
@@ -2615,32 +2711,8 @@ static CanSILFunctionType getSILFunctionType(
   SmallBitVector addressableParams;
   SmallBitVector conditionallyAddressableParams;
   {
-    std::optional<ActorIsolation> actorIsolation;
-    if (constant) {
-      if (constant->kind == SILDeclRef::Kind::Deallocator) {
-        actorIsolation = ActorIsolation::forNonisolated(false);
-      } else if (auto *decl = constant->getAbstractFunctionDecl();
-                 decl && decl->getExecutionBehavior().has_value()) {
-        switch (*decl->getExecutionBehavior()) {
-        case ExecutionKind::Concurrent:
-          actorIsolation = ActorIsolation::forNonisolated(false /*unsafe*/);
-          break;
-        case ExecutionKind::Caller:
-          actorIsolation = ActorIsolation::forCallerIsolationInheriting();
-          break;
-        }
-      } else {
-        actorIsolation =
-            getActorIsolationOfContext(constant->getInnermostDeclContext());
-      }
-    } else if (substFnInterfaceType->hasExtInfo() &&
-               substFnInterfaceType->getExtInfo()
-                   .getIsolation()
-                   .isNonIsolatedCaller()) {
-      // If our function type is a nonisolated caller and we can not infer from
-      // our constant, we must be caller isolation inheriting.
-      actorIsolation = ActorIsolation::forCallerIsolationInheriting();
-    }
+    auto actorIsolation = getSILFunctionTypeActorIsolation(
+        substFnInterfaceType, origConstant, constant);
     DestructureInputs destructurer(expansionContext, TC, conventions,
                                    foreignInfo, actorIsolation, inputs,
                                    parameterMap,
@@ -2655,12 +2727,12 @@ static CanSILFunctionType getSILFunctionType(
   destructureYieldsForCoroutine(TC, expansionContext, constant,
                                 coroutineOrigYieldType, coroutineSubstYieldType,
                                 yields, coroutineKind);
-  
+
   // Destructure the result tuple type.
   SmallVector<SILResultInfo, 8> results;
   {
     DestructureResults destructurer(expansionContext, TC, conventions, results,
-                                    hasSendingResult);
+                                    hasSendingResult, constant);
     destructurer.destructure(origResultType, substFormalResultType);
   }
 
@@ -2815,7 +2887,7 @@ static CanSILFunctionType getSILFunctionType(
           .withSendable(isSendable)
           .withAsync(isAsync)
           .withUnimplementable(unimplementable)
-          .withLifetimeDependencies(loweredLifetimes)
+          .withLifetimeDependencies(TC.Context.AllocateCopy(loweredLifetimes))
           .build();
 
   return SILFunctionType::get(genericSig, silExtInfo, coroutineKind,
@@ -2829,9 +2901,8 @@ static CanSILFunctionType getSILFunctionTypeForInitAccessor(
     TypeConverter &TC, TypeExpansionContext context,
     AbstractionPattern origType, CanAnyFunctionType substAccessorType,
     SILExtInfoBuilder extInfoBuilder, const Conventions &conventions,
-    SILDeclRef accessorRef) {
-  auto *accessor = cast<AccessorDecl>(accessorRef.getDecl());
-
+    SILDeclRef constant) {
+  auto *declContext = constant.getDecl()->getDeclContext();
   CanGenericSignature genericSig = substAccessorType.getOptGenericSignature();
 
   std::optional<TypeConverter::GenericContextRAII> contextRAII;
@@ -2860,8 +2931,10 @@ static CanSILFunctionType getSILFunctionTypeForInitAccessor(
     assert(!unimplementable && "should never have an opaque AP here");
   }
 
-  // Drop `self` parameter.
-  inputs.pop_back();
+  // Drop `self` parameter if inside a nominal context
+  // Local context do not include the `self` parameter
+  if (!declContext->isLocalContext())
+    inputs.pop_back();
 
   auto getLoweredTypeOfProperty = [&](VarDecl *property) {
     auto type = property->getInterfaceType();
@@ -2872,27 +2945,40 @@ static CanSILFunctionType getSILFunctionTypeForInitAccessor(
 
   // accessed properties appear as `inout` parameters because they could be
   // read from and modified.
-  for (auto *property : accessor->getAccessedProperties()) {
-    inputs.push_back(SILParameterInfo(getLoweredTypeOfProperty(property),
-                                      ParameterConvention::Indirect_Inout));
+  if (auto *accessor = dyn_cast<AccessorDecl>(constant.getDecl())) {
+    for (auto *property : accessor->getAccessedProperties()) {
+      inputs.push_back(SILParameterInfo(getLoweredTypeOfProperty(property),
+                                        ParameterConvention::Indirect_Inout));
+    }
   }
 
   // Make a new 'self' parameter.
-  auto selfInterfaceType = MetatypeType::get(
-      accessor->getDeclContext()->getSelfInterfaceType());
-  AbstractionPattern origSelfType(genericSig,
-                                  selfInterfaceType->getCanonicalType());
-  auto loweredSelfType = TC.getLoweredType(
-      origSelfType, selfInterfaceType->getCanonicalType(), context);
-  inputs.push_back(SILParameterInfo(loweredSelfType.getASTType(),
-                                    ParameterConvention::Direct_Unowned));
+  if (!declContext->isLocalContext()) {
+    auto selfInterfaceType = MetatypeType::get(
+        (genericSig)
+            ? declContext->getSelfInterfaceType()->getReducedType(genericSig)
+            : declContext->getSelfTypeInContext());
+    AbstractionPattern origSelfType(genericSig,
+                                    selfInterfaceType->getCanonicalType());
+    auto loweredSelfType = TC.getLoweredType(
+        origSelfType, selfInterfaceType->getCanonicalType(), context);
+    inputs.push_back(SILParameterInfo(loweredSelfType.getASTType(),
+                                      ParameterConvention::Direct_Unowned));
+  }
 
   SmallVector<SILResultInfo, 8> results;
 
   // initialized properties appear as `@out` results because they are
   // initialized by the accessor.
-  for (auto *property : accessor->getInitializedProperties()) {
-    results.push_back(SILResultInfo(getLoweredTypeOfProperty(property),
+  if (auto *accessor = dyn_cast<AccessorDecl>(constant.getDecl())) {
+    for (auto *property : accessor->getInitializedProperties()) {
+      results.push_back(SILResultInfo(getLoweredTypeOfProperty(property),
+                                      ResultConvention::Indirect));
+    }
+  } else {
+    auto *varDecl = dyn_cast<VarDecl>(constant.getDecl());
+    auto backingStorage = varDecl->getPropertyWrapperBackingProperty();
+    results.push_back(SILResultInfo(getLoweredTypeOfProperty(backingStorage),
                                     ResultConvention::Indirect));
   }
 
@@ -3188,7 +3274,8 @@ static CanSILFunctionType getNativeSILFunctionType(
       if (constant) {
         if (constant->isSetter()) {
           return getSILFunctionTypeForConventions(DefaultSetterConventions());
-        } else if (constant->isInitAccessor()) {
+        }
+        if (constant->isInitAccessor()) {
           return getSILFunctionTypeForInitAccessor(
               TC, context, origType, substInterfaceType, extInfoBuilder,
               DefaultSetterConventions(), *constant);
@@ -3207,6 +3294,10 @@ static CanSILFunctionType getNativeSILFunctionType(
     case SILDeclRef::Kind::IVarDestroyer:
       return getSILFunctionTypeForConventions(
           DefaultConventions(NormalParameterConvention::Guaranteed));
+    case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
+      return getSILFunctionTypeForInitAccessor(
+          TC, context, origType, substInterfaceType, extInfoBuilder,
+          DefaultSetterConventions(), *constant);
     case SILDeclRef::Kind::Deallocator:
       return getSILFunctionTypeForConventions(DeallocatorConventions());
     case SILDeclRef::Kind::IsolatedDeallocator: {
@@ -3389,7 +3480,7 @@ CanSILFunctionType swift::buildSILFunctionThunkType(
 
   // Add the formal parameters of the expected type to the thunk.
   auto contextConvention =
-      fn->getTypeLowering(sourceType).isTrivial()
+      fn->getTypeProperties(sourceType).isTrivial()
           ? ParameterConvention::Direct_Unowned
           : ParameterConvention::Direct_Guaranteed;
   SmallVector<SILParameterInfo, 4> params;
@@ -4046,8 +4137,7 @@ static ObjCSelectorFamily getObjCSelectorFamily(SILDeclRef c) {
       case AccessorKind::Set:
         break;
 #define OBJC_ACCESSOR(ID, KEYWORD)
-#define ACCESSOR(ID) \
-      case AccessorKind::ID:
+#define ACCESSOR(ID, KEYWORD) case AccessorKind::ID:
       case AccessorKind::DistributedGet:
 #include "swift/AST/AccessorKinds.def"
         llvm_unreachable("Unexpected AccessorKind of foreign FuncDecl");
@@ -4075,6 +4165,7 @@ static ObjCSelectorFamily getObjCSelectorFamily(SILDeclRef c) {
   case SILDeclRef::Kind::DefaultArgGenerator:
   case SILDeclRef::Kind::StoredPropertyInitializer:
   case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
+  case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
   case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
   case SILDeclRef::Kind::EntryPoint:
   case SILDeclRef::Kind::AsyncEntryPoint:
@@ -4283,10 +4374,12 @@ static CanSILFunctionType getUncachedSILFunctionTypeForConstant(
   // The type of the native-to-foreign thunk for a swift closure.
   if (constant.isForeign && constant.hasClosureExpr() &&
       shouldStoreClangType(TC.getDeclRefRepresentation(constant))) {
-    auto clangType = TC.Context.getClangFunctionType(
-        origLoweredInterfaceType->getParams(),
-        origLoweredInterfaceType->getResult(),
-        FunctionTypeRepresentation::CFunctionPointer);
+    auto clangType = extInfoBuilder.getClangTypeInfo().getType();
+    if (!clangType)
+      clangType = TC.Context.getClangFunctionType(
+          origLoweredInterfaceType->getParams(),
+          origLoweredInterfaceType->getResult(),
+          FunctionTypeRepresentation::CFunctionPointer);
     AbstractionPattern pattern =
         AbstractionPattern(origLoweredInterfaceType, clangType);
     return getSILFunctionTypeForAbstractCFunction(
@@ -4373,6 +4466,7 @@ TypeConverter::getDeclRefRepresentation(SILDeclRef c) {
     case SILDeclRef::Kind::DefaultArgGenerator:
     case SILDeclRef::Kind::StoredPropertyInitializer:
     case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
+    case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
     case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
     case SILDeclRef::Kind::IsolatedDeallocator:
       return SILFunctionTypeRepresentation::Thin;
@@ -4779,6 +4873,7 @@ static AbstractFunctionDecl *getBridgedFunction(SILDeclRef declRef) {
   case SILDeclRef::Kind::DefaultArgGenerator:
   case SILDeclRef::Kind::StoredPropertyInitializer:
   case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
+  case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
   case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
   case SILDeclRef::Kind::IVarInitializer:
   case SILDeclRef::Kind::IVarDestroyer:
@@ -4790,15 +4885,21 @@ static AbstractFunctionDecl *getBridgedFunction(SILDeclRef declRef) {
 }
 
 static AbstractionPattern
-getAbstractionPatternForConstant(ASTContext &ctx, SILDeclRef constant,
-                                 CanAnyFunctionType fnType,
+getAbstractionPatternForConstant(TypeConverter &converter, ASTContext &ctx,
+                                 SILDeclRef constant, CanAnyFunctionType fnType,
                                  unsigned numParameterLists) {
   if (!constant.isForeign)
     return AbstractionPattern(fnType);
 
+  if (auto *expr = constant.getAbstractClosureExpr()) {
+    auto &info = converter.getClosureTypeInfo(expr);
+    return info.OrigType;
+  }
+
   auto bridgedFn = getBridgedFunction(constant);
   if (!bridgedFn)
     return AbstractionPattern(fnType);
+
   const clang::Decl *clangDecl = bridgedFn->getClangDecl();
   if (!clangDecl)
     return AbstractionPattern(fnType);
@@ -4841,9 +4942,8 @@ TypeConverter::getLoweredFormalTypes(SILDeclRef constant,
   unsigned numParameterLists = constant.getParameterListCount();
 
   // Form an abstraction pattern for bridging purposes.
-  AbstractionPattern bridgingFnPattern =
-    getAbstractionPatternForConstant(Context, constant, fnType,
-                                     numParameterLists);
+  AbstractionPattern bridgingFnPattern = getAbstractionPatternForConstant(
+      *this, Context, constant, fnType, numParameterLists);
 
   auto extInfo = fnType->getExtInfo();
   SILFunctionTypeRepresentation rep = getDeclRefRepresentation(constant);
@@ -5254,11 +5354,20 @@ TypeExpansionContext::TypeExpansionContext(const SILFunction &f)
       inContext(f.getModule().getAssociatedContext()),
       isContextWholeModule(f.getModule().isWholeModule()) {}
 
+CanSILFunctionType SILFunction::getLoweredFunctionTypeInContext() const {
+  if (!LoweredTypeInContext) {
+    const_cast<SILFunction *>(this)->LoweredTypeInContext
+      = getLoweredFunctionTypeInContext(
+        getTypeExpansionContext());
+  }
+  return LoweredTypeInContext;
+}
+
 CanSILFunctionType SILFunction::getLoweredFunctionTypeInContext(
     TypeExpansionContext context) const {
   auto origFunTy = getLoweredFunctionType();
   auto &M = getModule();
-  auto funTy = M.Types.getLoweredType(origFunTy , context);
+  auto funTy = M.Types.getLoweredType(origFunTy, context);
   return cast<SILFunctionType>(funTy.getASTType());
 }
 
diff --git a/lib/SIL/IR/SILGlobalVariable.cpp b/lib/SIL/IR/SILGlobalVariable.cpp
index e9c85fd644193..241a39eb4126e 100644
--- a/lib/SIL/IR/SILGlobalVariable.cpp
+++ b/lib/SIL/IR/SILGlobalVariable.cpp
@@ -43,6 +43,28 @@ SILGlobalVariable *SILGlobalVariable::create(SILModule &M, SILLinkage linkage,
   return var;
 }
 
+ModuleDecl *SILGlobalVariable::getParentModule() const {
+  return ParentModule ? ParentModule : getModule().getSwiftModule();
+}
+
+static bool isGlobalLet(SILModule &mod, VarDecl *decl, SILType type) {
+  if (!decl)
+    return false;
+
+  if (!decl->isLet())
+    return false;
+
+  // Raw-layout storage may be mutated even for let-variables. Therefore don't
+  // treat such variables as `let` in SIL.
+  auto teCtxt = TypeExpansionContext::maximal(mod.getSwiftModule(),
+                                              mod.isWholeModule());
+  auto typeProps = mod.Types.getTypeProperties(type, teCtxt);
+  if (typeProps.isOrContainsRawLayout())
+    return false;
+
+  return true;
+}
+
 SILGlobalVariable::SILGlobalVariable(SILModule &Module, SILLinkage Linkage,
                                      SerializedKind_t serializedKind,
                                      StringRef Name, SILType LoweredType,
@@ -53,7 +75,8 @@ SILGlobalVariable::SILGlobalVariable(SILModule &Module, SILLinkage Linkage,
       Linkage(unsigned(Linkage)), HasLocation(Loc.has_value()), VDecl(Decl) {
   setSerializedKind(serializedKind);
   IsDeclaration = isAvailableExternally(Linkage);
-  setLet(Decl ? Decl->isLet() : false);
+  setLet(isGlobalLet(Module, Decl, LoweredType));
+  setMarkedAsUsed(Decl && Decl->getAttrs().hasAttribute<UsedAttr>());
   Module.silGlobals.push_back(this);
 }
 
@@ -65,10 +88,35 @@ bool SILGlobalVariable::isPossiblyUsedExternally() const {
   if (shouldBePreservedForDebugger())
     return true;
 
+  if (markedAsUsed())
+    return true;
+
+  if (getSectionAttr())
+    return true;
+
   SILLinkage linkage = getLinkage();
   return swift::isPossiblyUsedExternally(linkage, getModule().isWholeModule());
 }
 
+bool SILGlobalVariable::hasNonUniqueDefinition() const {
+  // Non-uniqueness is a property of the Embedded linkage model.
+  auto &ctx = getModule().getASTContext();
+  if (!ctx.LangOpts.hasFeature(Feature::Embedded))
+    return false;
+
+  // If this is for a declaration, ask it.
+  if (auto decl = getDecl()) {
+    return SILDeclRef::declHasNonUniqueDefinition(decl);
+  }
+
+  // If this variable is from a different module than the one we are emitting
+  // code for, then it must have a non-unique definition.
+  if (getParentModule() != getModule().getSwiftModule())
+    return true;
+
+  return false;
+}
+
 bool SILGlobalVariable::shouldBePreservedForDebugger() const {
   if (getModule().getOptions().OptMode != OptimizationMode::NoOptimization)
     return false;
diff --git a/lib/SIL/IR/SILInstruction.cpp b/lib/SIL/IR/SILInstruction.cpp
index 45b09113095da..137c57371e0e5 100644
--- a/lib/SIL/IR/SILInstruction.cpp
+++ b/lib/SIL/IR/SILInstruction.cpp
@@ -1009,7 +1009,8 @@ MemoryBehavior SILInstruction::getMemoryBehavior() const {
   if (auto *BI = dyn_cast<BuiltinInst>(this)) {
     // Handle Swift builtin functions.
     const BuiltinInfo &BInfo = BI->getBuiltinInfo();
-    if (BInfo.ID == BuiltinValueKind::ZeroInitializer) {
+    if (BInfo.ID == BuiltinValueKind::ZeroInitializer ||
+        BInfo.ID == BuiltinValueKind::PrepareInitialization) {
       // The address form of `zeroInitializer` writes to its argument to
       // initialize it. The value form has no side effects.
       return BI->getArguments().size() > 0
@@ -1025,15 +1026,15 @@ MemoryBehavior SILInstruction::getMemoryBehavior() const {
     // Handle LLVM intrinsic functions.
     const IntrinsicInfo &IInfo = BI->getIntrinsicInfo();
     if (IInfo.ID != llvm::Intrinsic::not_intrinsic) {
-      auto IAttrs = IInfo.getOrCreateAttributes(getModule().getASTContext());
+      auto &IAttrs = IInfo.getOrCreateFnAttributes(getModule().getASTContext());
       auto MemEffects = IAttrs.getMemoryEffects();
       // Read-only.
       if (MemEffects.onlyReadsMemory() &&
-          IAttrs.hasFnAttr(llvm::Attribute::NoUnwind))
+          IAttrs.hasAttribute(llvm::Attribute::NoUnwind))
         return MemoryBehavior::MayRead;
       // Read-none?
       return MemEffects.doesNotAccessMemory() &&
-                     IAttrs.hasFnAttr(llvm::Attribute::NoUnwind)
+                     IAttrs.hasAttribute(llvm::Attribute::NoUnwind)
                  ? MemoryBehavior::None
                  : MemoryBehavior::MayHaveSideEffects;
     }
@@ -1060,10 +1061,10 @@ MemoryBehavior SILInstruction::getMemoryBehavior() const {
     SILModule &M = ga->getFunction()->getModule();
     auto expansion = TypeExpansionContext::maximal(M.getAssociatedContext(),
                                                    M.isWholeModule());
-    const TypeLowering &tl =
-      M.Types.getTypeLowering(ga->getType().getObjectType(), expansion);
-    return tl.isFixedABI() ? MemoryBehavior::None :
-                             MemoryBehavior::MayHaveSideEffects;
+    SILTypeProperties props =
+      M.Types.getTypeProperties(ga->getType().getObjectType(), expansion);
+    return props.isFixedABI() ? MemoryBehavior::None
+                              : MemoryBehavior::MayHaveSideEffects;
   }
 
   if (auto *li = dyn_cast<LoadInst>(this)) {
@@ -1096,8 +1097,8 @@ MemoryBehavior SILInstruction::getMemoryBehavior() const {
     llvm_unreachable("Covered switch isn't covered?!");
   }
   
-  if (auto mdi = MarkDependenceInstruction(this)) {
-    if (mdi.getBase()->getType().isAddress())
+  if (auto *mdi = dyn_cast<MarkDependenceInst>(this)) {
+    if (mdi->getBase()->getType().isAddress())
       return MemoryBehavior::MayRead;
     return MemoryBehavior::None;
   }
@@ -1353,7 +1354,7 @@ bool SILInstruction::isDeallocatingStack() const {
 }
 
 static bool typeOrLayoutInvolvesPack(SILType ty, SILFunction const &F) {
-  return ty.hasAnyPack() || ty.isOrContainsPack(F);
+  return ty.isOrContainsPack(F);
 }
 
 bool SILInstruction::mayRequirePackMetadata(SILFunction const &F) const {
diff --git a/lib/SIL/IR/SILInstructions.cpp b/lib/SIL/IR/SILInstructions.cpp
index 5d4fdee039af2..06c61cc97af17 100644
--- a/lib/SIL/IR/SILInstructions.cpp
+++ b/lib/SIL/IR/SILInstructions.cpp
@@ -525,7 +525,7 @@ BuiltinInst::BuiltinInst(SILDebugLocation Loc, Identifier Name,
                          ArrayRef<SILValue> allOperands,
                          unsigned numNormalOperands)
     : InstructionBaseWithTrailingOperands(allOperands, Loc, ReturnType),
-      Name(Name), Substitutions(Subs), numNormalOperands(numNormalOperands) {}
+      Name(Name), Substitutions(Subs.getCanonical()), numNormalOperands(numNormalOperands) {}
 
 IncrementProfilerCounterInst *IncrementProfilerCounterInst::create(
     SILDebugLocation Loc, unsigned CounterIdx, StringRef PGOFuncName,
@@ -539,7 +539,7 @@ IncrementProfilerCounterInst *IncrementProfilerCounterInst::create(
       Loc, CounterIdx, PGOFuncNameLength, NumCounters, PGOFuncHash);
 
   std::uninitialized_copy(PGOFuncName.begin(), PGOFuncName.end(),
-                          Inst->getTrailingObjects<char>());
+                          Inst->getTrailingObjects());
   return Inst;
 }
 
@@ -554,7 +554,7 @@ SpecifyTestInst *SpecifyTestInst::create(SILDebugLocation Loc,
       ::new (Buffer) SpecifyTestInst(Loc, ArgumentsSpecificationLength);
   std::uninitialized_copy(ArgumentsSpecification.begin(),
                           ArgumentsSpecification.end(),
-                          Inst->getTrailingObjects<char>());
+                          Inst->getTrailingObjects());
   return Inst;
 }
 
@@ -1121,7 +1121,7 @@ IntegerLiteralInst::IntegerLiteralInst(SILDebugLocation Loc, SILType Ty,
     : InstructionBase(Loc, Ty) {
   sharedUInt32().IntegerLiteralInst.numBits = Value.getBitWidth();
   std::uninitialized_copy_n(Value.getRawData(), Value.getNumWords(),
-                            getTrailingObjects<llvm::APInt::WordType>());
+                            getTrailingObjects());
 }
 
 IntegerLiteralInst *IntegerLiteralInst::create(SILDebugLocation Loc,
@@ -1142,10 +1142,11 @@ IntegerLiteralInst *IntegerLiteralInst::create(SILDebugLocation Loc,
   return ::new (buf) IntegerLiteralInst(Loc, Ty, Value);
 }
 
-static APInt getAPInt(AnyBuiltinIntegerType *anyIntTy, intmax_t value) {
+static APInt getAPInt(AnyBuiltinIntegerType *anyIntTy, intmax_t value,
+                      bool treatAsSigned) {
   // If we're forming a fixed-width type, build using the greatest width.
   if (auto intTy = dyn_cast<BuiltinIntegerType>(anyIntTy))
-    return APInt(intTy->getGreatestWidth(), value);
+    return APInt(intTy->getGreatestWidth(), value, treatAsSigned);
 
   // Otherwise, build using the size of the type and then truncate to the
   // minimum width necessary.
@@ -1154,11 +1155,12 @@ static APInt getAPInt(AnyBuiltinIntegerType *anyIntTy, intmax_t value) {
   return result;
 }
 
-IntegerLiteralInst *IntegerLiteralInst::create(SILDebugLocation Loc,
-                                               SILType Ty, intmax_t Value,
+IntegerLiteralInst *IntegerLiteralInst::create(SILDebugLocation Loc, SILType Ty,
+                                               intmax_t Value,
+                                               bool treatAsSigned,
                                                SILModule &M) {
   auto intTy = Ty.castTo<AnyBuiltinIntegerType>();
-  return create(Loc, Ty, getAPInt(intTy, Value), M);
+  return create(Loc, Ty, getAPInt(intTy, Value, treatAsSigned), M);
 }
 
 static SILType getGreatestIntegerType(Type type, SILModule &M) {
@@ -1180,8 +1182,7 @@ IntegerLiteralInst *IntegerLiteralInst::create(IntegerLiteralExpr *E,
 /// getValue - Return the APInt for the underlying integer literal.
 APInt IntegerLiteralInst::getValue() const {
   auto numBits = sharedUInt32().IntegerLiteralInst.numBits;
-  return APInt(numBits, {getTrailingObjects<llvm::APInt::WordType>(),
-                         getWordsForBitWidth(numBits)});
+  return APInt(numBits, getTrailingObjects(getWordsForBitWidth(numBits)));
 }
 
 FloatLiteralInst::FloatLiteralInst(SILDebugLocation Loc, SILType Ty,
@@ -1189,7 +1190,7 @@ FloatLiteralInst::FloatLiteralInst(SILDebugLocation Loc, SILType Ty,
     : InstructionBase(Loc, Ty) {
   sharedUInt32().FloatLiteralInst.numBits = Bits.getBitWidth();
   std::uninitialized_copy_n(Bits.getRawData(), Bits.getNumWords(),
-                            getTrailingObjects<llvm::APInt::WordType>());
+                            getTrailingObjects());
 }
 
 FloatLiteralInst *FloatLiteralInst::create(SILDebugLocation Loc, SILType Ty,
@@ -1220,8 +1221,7 @@ FloatLiteralInst *FloatLiteralInst::create(FloatLiteralExpr *E,
 
 APInt FloatLiteralInst::getBits() const {
   auto numBits = sharedUInt32().FloatLiteralInst.numBits;
-  return APInt(numBits, {getTrailingObjects<llvm::APInt::WordType>(),
-                         getWordsForBitWidth(numBits)});
+  return APInt(numBits, getTrailingObjects(getWordsForBitWidth(numBits)));
 }
 
 APFloat FloatLiteralInst::getValue() const {
@@ -1234,7 +1234,7 @@ StringLiteralInst::StringLiteralInst(SILDebugLocation Loc, StringRef Text,
     : InstructionBase(Loc, Ty) {
   sharedUInt8().StringLiteralInst.encoding = uint8_t(encoding);
   sharedUInt32().StringLiteralInst.length = Text.size();
-  memcpy(getTrailingObjects<char>(), Text.data(), Text.size());
+  memcpy(getTrailingObjects(), Text.data(), Text.size());
 
   // It is undefined behavior to feed ill-formed UTF-8 into `Swift.String`;
   // however, the compiler creates string literals in many places, so there's a
@@ -1260,7 +1260,7 @@ CondFailInst::CondFailInst(SILDebugLocation DebugLoc, SILValue Operand,
                            StringRef Message)
       : UnaryInstructionBase(DebugLoc, Operand),
         MessageSize(Message.size()) {
-  memcpy(getTrailingObjects<char>(), Message.data(), Message.size());
+  memcpy(getTrailingObjects(), Message.data(), Message.size());
 }
 
 CondFailInst *CondFailInst::create(SILDebugLocation DebugLoc, SILValue Operand,
@@ -1315,35 +1315,26 @@ AssignInst::AssignInst(SILDebugLocation Loc, SILValue Src, SILValue Dest,
   sharedUInt8().AssignInst.ownershipQualifier = uint8_t(Qualifier);
 }
 
-AssignByWrapperInst::AssignByWrapperInst(SILDebugLocation Loc,
-                                         SILValue Src, SILValue Dest,
-                                         SILValue Initializer, SILValue Setter,
-                                         AssignByWrapperInst::Mode mode)
-    : AssignInstBase(Loc, Src, Dest, Initializer, Setter) {
-  assert(Initializer->getType().is<SILFunctionType>());
-  sharedUInt8().AssignByWrapperInst.mode = uint8_t(mode);
-}
-
 AssignOrInitInst::AssignOrInitInst(SILDebugLocation Loc, VarDecl *P,
-                                   SILValue Self, SILValue Src,
+                                   SILValue SelfOrLocal, SILValue Src,
                                    SILValue Initializer, SILValue Setter,
                                    AssignOrInitInst::Mode Mode)
     : InstructionBase<SILInstructionKind::AssignOrInitInst,
                       NonValueInstruction>(Loc),
-      Operands(this, Self, Src, Initializer, Setter), Property(P) {
+      Operands(this, SelfOrLocal, Src, Initializer, Setter), Property(P) {
   assert(Initializer->getType().is<SILFunctionType>());
   sharedUInt8().AssignOrInitInst.mode = uint8_t(Mode);
   Assignments.resize(getNumInitializedProperties());
 }
 
 void AssignOrInitInst::markAsInitialized(VarDecl *property) {
-  auto toInitProperties = getInitializedProperties();
-  for (unsigned index : indices(toInitProperties)) {
-    if (toInitProperties[index] == property) {
-      markAsInitialized(index);
-      break;
+  unsigned idx = 0;
+  this->forEachInitializedProperty([&](VarDecl *p) {
+    if (p == property) {
+      markAsInitialized(idx);
     }
-  }
+    idx++;
+  });
 }
 
 void AssignOrInitInst::markAsInitialized(unsigned propertyIdx) {
@@ -1364,14 +1355,28 @@ AccessorDecl *AssignOrInitInst::getReferencedInitAccessor() const {
   return Property->getOpaqueAccessor(AccessorKind::Init);
 }
 
+DeclContext *AssignOrInitInst::getDeclContextOrNull() const {
+  if (auto accessorDecl = getReferencedInitAccessor())
+    return accessorDecl->getDeclContext();
+  return getProperty()->getDeclContext();
+}
+
 unsigned AssignOrInitInst::getNumInitializedProperties() const {
-  return getInitializedProperties().size();
+  unsigned count = 0;
+  forEachInitializedProperty([&](VarDecl *property) { count++; });
+  return count;
 }
 
-ArrayRef<VarDecl *> AssignOrInitInst::getInitializedProperties() const {
-  if (auto *accessor = getReferencedInitAccessor())
-    return accessor->getInitializedProperties();
-  return {};
+void AssignOrInitInst::forEachInitializedProperty(
+    llvm::function_ref<void(VarDecl *)> callback) const {
+  if (auto *accessor = getReferencedInitAccessor()) {
+    for (auto *property : accessor->getInitializedProperties())
+      callback(property);
+  } else {
+    // Only the backing storage property/local variavle
+    auto *backingVar = Property->getPropertyWrapperBackingProperty();
+    callback(backingVar);
+  }
 }
 
 ArrayRef<VarDecl *> AssignOrInitInst::getAccessedProperties() const {
@@ -1441,15 +1446,16 @@ UncheckedRefCastAddrInst::create(SILDebugLocation Loc, SILValue src,
 }
 
 UnconditionalCheckedCastAddrInst::UnconditionalCheckedCastAddrInst(
-    SILDebugLocation Loc, CastingIsolatedConformances isolatedConformances,
+    SILDebugLocation Loc, CheckedCastInstOptions options,
     SILValue src, CanType srcType, SILValue dest,
     CanType targetType, ArrayRef<SILValue> TypeDependentOperands)
     : AddrCastInstBase(Loc, src, srcType, dest, targetType,
         TypeDependentOperands),
-      IsolatedConformances(isolatedConformances) {}
+      Options(options) {}
 
 UnconditionalCheckedCastAddrInst *
-UnconditionalCheckedCastAddrInst::create(SILDebugLocation Loc, CastingIsolatedConformances isolatedConformances, SILValue src,
+UnconditionalCheckedCastAddrInst::create(SILDebugLocation Loc,
+        CheckedCastInstOptions options, SILValue src,
         CanType srcType, SILValue dest, CanType targetType, SILFunction &F) {
   SILModule &Mod = F.getModule();
   SmallVector<SILValue, 4> allOperands;
@@ -1458,12 +1464,12 @@ UnconditionalCheckedCastAddrInst::create(SILDebugLocation Loc, CastingIsolatedCo
       totalSizeToAlloc<swift::Operand>(2 + allOperands.size());
   void *Buffer = Mod.allocateInst(size, alignof(UnconditionalCheckedCastAddrInst));
   return ::new (Buffer) UnconditionalCheckedCastAddrInst(
-    Loc, isolatedConformances, src, srcType, dest, targetType, allOperands);
+    Loc, options, src, srcType, dest, targetType, allOperands);
 }
 
 CheckedCastAddrBranchInst::CheckedCastAddrBranchInst(
   SILDebugLocation DebugLoc,
-  CastingIsolatedConformances isolatedConformances,
+  CheckedCastInstOptions options,
   CastConsumptionKind consumptionKind,
   SILValue src, CanType srcType, SILValue dest, CanType targetType,
   ArrayRef<SILValue> TypeDependentOperands,
@@ -1472,14 +1478,14 @@ CheckedCastAddrBranchInst::CheckedCastAddrBranchInst(
       : AddrCastInstBase(DebugLoc, src, srcType, dest,
             targetType, TypeDependentOperands, consumptionKind,
             successBB, failureBB, Target1Count, Target2Count),
-        IsolatedConformances(isolatedConformances) {
+        Options(options) {
   assert(consumptionKind != CastConsumptionKind::BorrowAlways &&
          "BorrowAlways is not supported on addresses");
 }
 
 CheckedCastAddrBranchInst *
 CheckedCastAddrBranchInst::create(SILDebugLocation DebugLoc,
-         CastingIsolatedConformances isolatedConformances,
+         CheckedCastInstOptions options,
          CastConsumptionKind consumptionKind,
          SILValue src, CanType srcType, SILValue dest, CanType targetType,
          SILBasicBlock *successBB, SILBasicBlock *failureBB,
@@ -1492,7 +1498,7 @@ CheckedCastAddrBranchInst::create(SILDebugLocation DebugLoc,
       totalSizeToAlloc<swift::Operand>(2 + allOperands.size());
   void *Buffer = Mod.allocateInst(size, alignof(CheckedCastAddrBranchInst));
   return ::new (Buffer) CheckedCastAddrBranchInst(
-    DebugLoc, isolatedConformances, consumptionKind,
+    DebugLoc, options, consumptionKind,
     src, srcType, dest, targetType, allOperands,
     successBB, failureBB, Target1Count, Target2Count);
 }
@@ -1508,8 +1514,9 @@ StructInst *StructInst::create(SILDebugLocation Loc, SILType Ty,
 StructInst::StructInst(SILDebugLocation Loc, SILType Ty,
                        ArrayRef<SILValue> Elems,
                        ValueOwnershipKind forwardingOwnershipKind)
-    : InstructionBaseWithTrailingOperands(Elems, Loc, Ty,
-                                          forwardingOwnershipKind) {
+    : InstructionBaseWithTrailingOperands(
+      Elems, Loc, Ty, forwardingOwnershipKind.forwardToInit(Ty))
+{
   assert(!Ty.getStructOrBoundGenericStruct()->hasUnreferenceableStorage());
 }
 
@@ -2691,7 +2698,7 @@ UncheckedBitwiseCastInst::create(SILDebugLocation DebugLoc, SILValue Operand,
 }
 
 UnconditionalCheckedCastInst *UnconditionalCheckedCastInst::create(
-    SILDebugLocation DebugLoc, CastingIsolatedConformances isolatedConformances,
+    SILDebugLocation DebugLoc, CheckedCastInstOptions options,
     SILValue Operand, SILType DestLoweredTy,
     CanType DestFormalTy, SILFunction &F,
     ValueOwnershipKind forwardingOwnershipKind) {
@@ -2702,13 +2709,13 @@ UnconditionalCheckedCastInst *UnconditionalCheckedCastInst::create(
       totalSizeToAlloc<swift::Operand>(1 + TypeDependentOperands.size());
   void *Buffer = Mod.allocateInst(size, alignof(UnconditionalCheckedCastInst));
   return ::new (Buffer) UnconditionalCheckedCastInst(
-      DebugLoc, isolatedConformances, Operand, TypeDependentOperands,
+      DebugLoc, options, Operand, TypeDependentOperands,
       DestLoweredTy, DestFormalTy, forwardingOwnershipKind);
 }
 
 CheckedCastBranchInst *CheckedCastBranchInst::create(
     SILDebugLocation DebugLoc, bool IsExact,
-    CastingIsolatedConformances isolatedConformances, SILValue Operand,
+    CheckedCastInstOptions options, SILValue Operand,
     CanType SrcFormalTy, SILType DestLoweredTy, CanType DestFormalTy,
     SILBasicBlock *SuccessBB, SILBasicBlock *FailureBB, SILFunction &F,
     ProfileCounter Target1Count, ProfileCounter Target2Count,
@@ -2722,7 +2729,7 @@ CheckedCastBranchInst *CheckedCastBranchInst::create(
       totalSizeToAlloc<swift::Operand>(3 + TypeDependentOperands.size());
   void *Buffer = module.allocateInst(size, alignof(CheckedCastBranchInst));
   return ::new (Buffer) CheckedCastBranchInst(
-      DebugLoc, IsExact, isolatedConformances, Operand, SrcFormalTy,
+      DebugLoc, IsExact, options, Operand, SrcFormalTy,
       TypeDependentOperands,
       DestLoweredTy, DestFormalTy, SuccessBB, FailureBB, Target1Count,
       Target2Count, forwardingOwnershipKind, preservesOwnership);
@@ -3064,14 +3071,14 @@ KeyPathPattern::KeyPathPattern(CanGenericSignature signature,
     Signature(signature), RootType(rootType), ValueType(valueType),
     ObjCString(objcString)
 {
-  auto *componentsBuf = getTrailingObjects<KeyPathPatternComponent>();
+  auto *componentsBuf = getTrailingObjects();
   std::uninitialized_copy(components.begin(), components.end(),
                           componentsBuf);
 }
 
 ArrayRef<KeyPathPatternComponent>
 KeyPathPattern::getComponents() const {
-  return {getTrailingObjects<KeyPathPatternComponent>(), NumComponents};
+  return getTrailingObjects(NumComponents);
 }
 
 void KeyPathPattern::Profile(llvm::FoldingSetNodeID &ID,
@@ -3172,10 +3179,10 @@ KeyPathInst::KeyPathInst(SILDebugLocation Loc,
     Pattern(Pattern),
     numPatternOperands(numPatternOperands),
     numTypeDependentOperands(allOperands.size() - numPatternOperands),
-    Substitutions(Subs)
+    Substitutions(Subs.getCanonical())
 {
   assert(allOperands.size() >= numPatternOperands);
-  auto *operandsBuf = getTrailingObjects<Operand>();
+  auto *operandsBuf = getTrailingObjects();
   for (unsigned i = 0; i < allOperands.size(); ++i) {
     ::new ((void*)&operandsBuf[i]) Operand(this, allOperands[i]);
   }
@@ -3188,7 +3195,7 @@ KeyPathInst::KeyPathInst(SILDebugLocation Loc,
 
 MutableArrayRef<Operand>
 KeyPathInst::getAllOperands() {
-  return {getTrailingObjects<Operand>(), numPatternOperands + numTypeDependentOperands};
+  return getTrailingObjects(numPatternOperands + numTypeDependentOperands);
 }
 
 KeyPathInst::~KeyPathInst() {
diff --git a/lib/SIL/IR/SILModule.cpp b/lib/SIL/IR/SILModule.cpp
index 7c71060aac068..ff87beb0d1b8d 100644
--- a/lib/SIL/IR/SILModule.cpp
+++ b/lib/SIL/IR/SILModule.cpp
@@ -112,7 +112,6 @@ SILModule::SILModule(llvm::PointerUnion<FileUnit *, ModuleDecl *> context,
     : Stage(SILStage::Raw), loweredAddresses(!Options.EnableSILOpaqueValues),
       indexTrieRoot(new IndexTrieNode()), Options(Options),
       irgenOptions(irgenOptions), serialized(false),
-      regDeserializationNotificationHandlerForNonTransparentFuncOME(false),
       regDeserializationNotificationHandlerForAllFuncOME(false),
       hasAccessMarkerHandler(false),
       prespecializedFunctionDeclsImported(false), SerializeSILAction(),
@@ -121,7 +120,7 @@ SILModule::SILModule(llvm::PointerUnion<FileUnit *, ModuleDecl *> context,
   if (auto *file = context.dyn_cast<FileUnit *>()) {
     AssociatedDeclContext = file;
   } else {
-    AssociatedDeclContext = context.get<ModuleDecl *>();
+    AssociatedDeclContext = cast<ModuleDecl *>(context);
   }
   TheSwiftModule = AssociatedDeclContext->getParentModule();
 
@@ -240,14 +239,28 @@ void SILModule::flushDeletedInsts() {
 
 SILWitnessTable *
 SILModule::lookUpWitnessTable(const ProtocolConformance *C) {
-  assert(C && "null conformance passed to lookUpWitnessTable");
+  // First try to lookup a specialized witness table for that conformance.
+  if (auto *wt = lookUpWitnessTable(C, /*isSpecialized=*/true)) {
+    return wt;
+  }
+  return lookUpWitnessTable(C, /*isSpecialized=*/false);
+}
 
-  // Attempt to lookup the witness table from the table.
-  auto found = WitnessTableMap.find(C);
-  if (found == WitnessTableMap.end())
-    return nullptr;
+SILWitnessTable *
+SILModule::lookUpWitnessTable(const ProtocolConformance *C, bool isSpecialized) {
+  assert(C && "null conformance passed to lookUpWitnessTable");
 
-  return found->second;
+  if (isSpecialized) {
+    // First try to lookup a specialized witness table for that conformance.
+    auto foundSpec = specializedWitnessTableMap.find(C);
+    if (foundSpec != specializedWitnessTableMap.end())
+      return foundSpec->second;
+  } else if (auto *rootConf = dyn_cast<RootProtocolConformance>(C)) {
+    auto found = WitnessTableMap.find(rootConf);
+    if (found != WitnessTableMap.end())
+      return found->second;
+  }
+  return nullptr;
 }
 
 SILDefaultWitnessTable *
@@ -287,7 +300,9 @@ void SILModule::deleteWitnessTable(SILWitnessTable *Wt) {
   auto Conf = Wt->getConformance();
   assert(lookUpWitnessTable(Conf) == Wt);
   getSILLoader()->invalidateWitnessTable(Wt);
-  WitnessTableMap.erase(Conf);
+  specializedWitnessTableMap.erase(Conf);
+  if (auto *rootConf = dyn_cast<RootProtocolConformance>(Conf))
+    WitnessTableMap.erase(rootConf);
   witnessTables.erase(Wt);
 }
 
@@ -417,6 +432,10 @@ bool SILModule::linkFunction(SILFunction *F, SILModule::LinkingMode Mode) {
   return SILLinkerVisitor(*this, Mode).processFunction(F);
 }
 
+bool SILModule::linkWitnessTable(ProtocolConformance *PC, SILModule::LinkingMode Mode) {
+  return SILLinkerVisitor(*this, Mode).processConformance(ProtocolConformanceRef(PC));
+}
+
 bool SILModule::hasFunction(StringRef Name) {
   if (lookUpFunction(Name))
     return true;
@@ -579,15 +598,24 @@ SILModule::lookUpFunctionInWitnessTable(ProtocolConformanceRef C,
     linker.processConformance(C);
   }
   ProtocolConformance *conf = C.getConcrete();
-  if (auto *inheritedC = dyn_cast<InheritedProtocolConformance>(conf))
-    conf = inheritedC->getInheritedConformance();
-
-  if (!isa<SpecializedProtocolConformance>(conf) || !lookupInSpecializedWitnessTable) {
-    conf = conf->getRootConformance();
+  SILWitnessTable *wt = nullptr;
+
+  if (lookupInSpecializedWitnessTable) {
+    wt = lookUpWitnessTable(conf);
+    if (!wt) {
+      if (auto *inheritedC = dyn_cast<InheritedProtocolConformance>(conf)) {
+        conf = inheritedC->getInheritedConformance();
+        wt = lookUpWitnessTable(conf);
+      }
+      if (!wt && !isa<SpecializedProtocolConformance>(conf)) {
+        conf = conf->getRootConformance();
+        wt = lookUpWitnessTable(conf);
+      }
+    }
+  } else {
+    wt = lookUpWitnessTable(conf->getRootConformance());
   }
 
-  SILWitnessTable *wt = lookUpWitnessTable(conf);
-
   if (!wt) {
     LLVM_DEBUG(llvm::dbgs() << "        Failed speculative lookup of "
                "witness for: ";
@@ -814,14 +842,15 @@ void SILModule::notifyAddedInstruction(SILInstruction *inst) {
     SILValue &val = RootLocalArchetypeDefs[{genericEnv, inst->getFunction()}];
     if (val) {
       if (!isa<PlaceholderValue>(val)) {
-        // Print a useful error message (and not just abort with an assert).
-        llvm::errs() << "re-definition of local environment in function "
-                     << inst->getFunction()->getName() << ":\n";
-        inst->print(llvm::errs());
-        llvm::errs() << "previously defined in function "
-                     << val->getFunction()->getName() << ":\n";
-        val->print(llvm::errs());
-        abort();
+        ABORT([&](auto &out) {
+          // Print a useful error message (and not just abort with an assert).
+          out << "re-definition of local environment in function "
+              << inst->getFunction()->getName() << ":\n";
+          inst->print(out);
+          out << "previously defined in function "
+              << val->getFunction()->getName() << ":\n";
+          val->print(out);
+        });
       }
       // The local environment was unresolved so far. Replace the placeholder
       // by inst.
@@ -859,8 +888,8 @@ void SILModule::notifyMovedInstruction(SILInstruction *inst,
 bool SILModule::isNoReturnBuiltinOrIntrinsic(Identifier Name) {
   const auto &IntrinsicInfo = getIntrinsicInfo(Name);
   if (IntrinsicInfo.ID != llvm::Intrinsic::not_intrinsic) {
-    return IntrinsicInfo.getOrCreateAttributes(getASTContext())
-        .hasFnAttr(llvm::Attribute::NoReturn);
+    return IntrinsicInfo.getOrCreateFnAttributes(getASTContext())
+        .hasAttribute(llvm::Attribute::NoReturn);
   }
   const auto &BuiltinInfo = getBuiltinInfo(Name);
   switch (BuiltinInfo.ID) {
diff --git a/lib/SIL/IR/SILPrinter.cpp b/lib/SIL/IR/SILPrinter.cpp
index 9e2337336ac65..70e67165357ed 100644
--- a/lib/SIL/IR/SILPrinter.cpp
+++ b/lib/SIL/IR/SILPrinter.cpp
@@ -95,6 +95,11 @@ llvm::cl::opt<bool> SILPrintGenericSpecializationInfo(
     llvm::cl::desc("Include generic specialization"
                    "information info in SIL output"));
 
+llvm::cl::opt<bool> SILPrintFunctionIsolationInfo(
+    "sil-print-function-isolation-info", llvm::cl::init(false),
+    llvm::cl::desc("Print out isolation info on functions in a manner that SIL "
+                   "understands [e.x.: not in comments]"));
+
 static std::string demangleSymbol(StringRef Name) {
   if (SILFullDemangle)
     return Demangle::demangleSymbolAsString(Name);
@@ -332,11 +337,27 @@ void SILDeclRef::print(raw_ostream &OS) const {
     auto *accessor = dyn_cast<AccessorDecl>(getDecl());
     if (!accessor) {
       printValueDecl(getDecl(), OS);
+      if (isDistributed()) {
+        OS << "!distributed";
+        OS << "(" << getDecl() << ")";
+      }
+      if (isDistributedThunk()) {
+        OS << "!distributed_thunk";
+        OS << "(" << getDecl() << ")";
+      }
       isDot = false;
       break;
     }
 
     printValueDecl(accessor->getStorage(), OS);
+    if (isDistributed()) {
+      OS << "!distributed";
+      OS << "(" << getDecl() << ")";
+    }
+    if (isDistributedThunk()) {
+      OS << "!distributed_thunk";
+      OS << "(" << getDecl() << ")";
+    }
     switch (accessor->getAccessorKind()) {
     case AccessorKind::WillSet:
       OS << "!willSet";
@@ -374,6 +395,12 @@ void SILDeclRef::print(raw_ostream &OS) const {
     case AccessorKind::Modify2:
       OS << "!modify2";
       break;
+    case AccessorKind::Borrow:
+      OS << "!borrow";
+      break;
+    case AccessorKind::Mutate:
+      OS << "!mutate";
+      break;
     }
     break;
   }
@@ -420,6 +447,9 @@ void SILDeclRef::print(raw_ostream &OS) const {
   case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
     OS << "!backinginit";
     break;
+  case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
+    OS << "!wrappedfieldinitaccessor";
+    break;
   case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
     OS << "!projectedvalueinit";
     break;
@@ -1024,8 +1054,8 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
 
   //===--------------------------------------------------------------------===//
   // SILInstruction Printing Logic
-  void printCastingIsolatedConformancesIfNeeded(CastingIsolatedConformances flag) {
-    switch (flag) {
+  void printCheckedCastInstOptions(CheckedCastInstOptions options) {
+    switch (options.isolatedConformances()) {
     case CastingIsolatedConformances::Allow:
       break;
 
@@ -1185,7 +1215,7 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
       if (auto *F = DS->Parent.dyn_cast<SILFunction *>())
         *this << "@" << F->getName() << " : $" << F->getLoweredFunctionType();
       else {
-        auto *PS = DS->Parent.get<const SILDebugScope *>();
+        auto *PS = cast<const SILDebugScope *>(DS->Parent);
         *this << Ctx.getScopeID(PS);
       }
       if (auto *CS = DS->InlinedCallSite)
@@ -1946,27 +1976,6 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
     *this << getIDAndType(AI->getDest());
   }
 
-  void visitAssignByWrapperInst(AssignByWrapperInst *AI) {
-    *this << getIDAndType(AI->getSrc()) << " to ";
-    switch (AI->getMode()) {
-    case AssignByWrapperInst::Unknown:
-      break;
-    case AssignByWrapperInst::Initialization:
-      *this << "[init] ";
-      break;
-    case AssignByWrapperInst::Assign:
-      *this << "[assign] ";
-      break;
-    case AssignByWrapperInst::AssignWrappedValue:
-      *this << "[assign_wrapped_value] ";
-      break;
-    }
-
-    *this << getIDAndType(AI->getDest())
-          << ", init " << getIDAndType(AI->getInitializer())
-          << ", set " << getIDAndType(AI->getSetter());
-  }
-
   void visitAssignOrInitInst(AssignOrInitInst *AI) {
     switch (AI->getMode()) {
     case AssignOrInitInst::Unknown:
@@ -1987,10 +1996,15 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
     }
 
     *this << "#";
-    printFullContext(AI->getProperty()->getDeclContext(), PrintState.OS);
-    *this << AI->getPropertyName();
+    auto declContext = AI->getProperty()->getDeclContext();
 
-    *this << ", self " << getIDAndType(AI->getSelf());
+    if (!declContext->isLocalContext()) {
+      printFullContext(declContext, PrintState.OS);
+      *this << AI->getPropertyName() << ", self ";
+    } else {
+      *this << AI->getPropertyName() << ", local ";
+    }
+    *this << getIDAndType(AI->getSelfOrLocalOperand());
     *this << ", value " << getIDAndType(AI->getSrc());
     *this << ", init " << getIDAndType(AI->getInitializer())
           << ", set " << getIDAndType(AI->getSetter());
@@ -2091,13 +2105,13 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
   }
 
   void visitUnconditionalCheckedCastInst(UnconditionalCheckedCastInst *CI) {
-    printCastingIsolatedConformancesIfNeeded(CI->getIsolatedConformances());
+    printCheckedCastInstOptions(CI->getCheckedCastOptions());
     *this << getIDAndType(CI->getOperand()) << " to " << CI->getTargetFormalType();
     printForwardingOwnershipKind(CI, CI->getOperand());
   }
   
   void visitCheckedCastBranchInst(CheckedCastBranchInst *CI) {
-    printCastingIsolatedConformancesIfNeeded(CI->getIsolatedConformances());
+    printCheckedCastInstOptions(CI->getCheckedCastOptions());
     if (CI->isExact())
       *this << "[exact] ";
     *this << CI->getSourceFormalType() << " in ";
@@ -2112,14 +2126,14 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
   }
 
   void visitUnconditionalCheckedCastAddrInst(UnconditionalCheckedCastAddrInst *CI) {
-    printCastingIsolatedConformancesIfNeeded(CI->getIsolatedConformances());
+    printCheckedCastInstOptions(CI->getCheckedCastOptions());
     *this << CI->getSourceFormalType() << " in " << getIDAndType(CI->getSrc())
           << " to " << CI->getTargetFormalType() << " in "
           << getIDAndType(CI->getDest());
   }
 
   void visitCheckedCastAddrBranchInst(CheckedCastAddrBranchInst *CI) {
-    printCastingIsolatedConformancesIfNeeded(CI->getIsolatedConformances());
+    printCheckedCastInstOptions(CI->getCheckedCastOptions());
     *this << getCastConsumptionKindName(CI->getConsumptionKind()) << ' '
           << CI->getSourceFormalType() << " in " << getIDAndType(CI->getSrc())
           << " to " << CI->getTargetFormalType() << " in "
@@ -2500,6 +2514,9 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
     printFullContext(EI->getField()->getDeclContext(), PrintState.OS);
     *this << EI->getField()->getName().get();
   }
+  void visitVectorBaseAddrInst(VectorBaseAddrInst *vbai) {
+    *this << getIDAndType(vbai->getVector());
+  }
   void visitRefElementAddrInst(RefElementAddrInst *EI) {
     *this << (EI->isImmutable() ? "[immutable] " : "")
           << getIDAndType(EI->getOperand()) << ", #";
@@ -2763,6 +2780,9 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
       *this << "[keep_unique] ";
     *this << getIDAndType(ECMI->getOperand());
   }
+  void visitEndCOWMutationAddrInst(EndCOWMutationAddrInst *ECMI) {
+    *this << getIDAndType(ECMI->getOperand());
+  }
   void visitEndInitLetRefInst(EndInitLetRefInst *I) {
     *this << getIDAndType(I->getOperand());
   }
@@ -3608,8 +3628,18 @@ void SILFunction::print(SILPrintContext &PrintCtx) const {
     OS << "[available " << availability.getVersionString() << "] ";
   }
 
+  // This is here only for testing purposes.
+  if (SILPrintFunctionIsolationInfo) {
+    if (auto isolation = getActorIsolation()) {
+      OS << "[isolation \"";
+      isolation->printForSIL(OS);
+      OS << "\"] ";
+    }
+  }
+
   switch (getInlineStrategy()) {
     case NoInline: OS << "[noinline] "; break;
+    case HeuristicAlwaysInline: OS << "[heuristic_always_inline] "; break;
     case AlwaysInline: OS << "[always_inline] "; break;
     case InlineDefault: break;
   }
@@ -3629,6 +3659,7 @@ void SILFunction::print(SILPrintContext &PrintCtx) const {
     case PerformanceConstraints::NoRuntime:      OS << "[no_runtime] "; break;
     case PerformanceConstraints::NoExistentials: OS << "[no_existentials] "; break;
     case PerformanceConstraints::NoObjCBridging: OS << "[no_objc_bridging] "; break;
+    case PerformanceConstraints::ManualOwnership: OS << "[manual_ownership] "; break;
   }
 
   if (isPerformanceConstraint())
@@ -3739,6 +3770,9 @@ void SILGlobalVariable::print(llvm::raw_ostream &OS, bool Verbose) const {
   if (isLet())
     OS << "[let] ";
 
+  if (markedAsUsed())
+    OS << "[used] ";
+
   printName(OS);
   OS << " : " << LoweredType;
 
@@ -4350,7 +4384,7 @@ void SILWitnessTable::Entry::print(llvm::raw_ostream &out, bool verbose,
       conformance.getConcrete()->printName(out, options);
     else {
       out << "dependent ";
-      assocProtoWitness.SubstType->print(out, options);
+      assocProtoWitness.Witness.getType()->print(out, options);
     }
     break;
   }
@@ -4373,6 +4407,9 @@ void SILWitnessTable::print(llvm::raw_ostream &OS, bool Verbose) const {
   printLinkage(OS, getLinkage(), /*isDefinition*/ isDefinition());
   printSerializedKind(OS, getSerializedKind());
 
+  if (isSpecialized())
+    OS << "[specialized] ";
+
   getConformance()->printName(OS, Options);
   Options.GenericSig =
     getConformance()->getDeclContext()->getGenericSignatureOfContext()
@@ -4392,18 +4429,21 @@ void SILWitnessTable::print(llvm::raw_ostream &OS, bool Verbose) const {
   for (auto conditionalConformance : getConditionalConformances()) {
     // conditional_conformance (TypeName: Protocol):
     // <conformance>
-    if (conditionalConformance.Conformance.isInvalid())
+    if (conditionalConformance.isInvalid()) {
+      OS << "  conditional_conformance invalid";
       continue;
+    }
 
     OS << "  conditional_conformance (";
-    conditionalConformance.Requirement.print(OS, Options);
-    OS << ": " << conditionalConformance.Conformance.getProtocol()->getName()
+    conditionalConformance.getType().print(OS, Options);
+    OS << ": " << conditionalConformance.getProtocol()->getName()
        << "): ";
-    if (conditionalConformance.Conformance.isConcrete())
-      conditionalConformance.Conformance.getConcrete()->printName(OS, Options);
+    if (conditionalConformance.isConcrete())
+      conditionalConformance.getConcrete()->printName(OS, Options);
     else {
+      ASSERT(conditionalConformance.isAbstract() && "Handle pack conformance here");
       OS << "dependent ";
-      conditionalConformance.Requirement->print(OS, Options);
+      conditionalConformance.getType()->print(OS, Options);
     }
 
     OS << '\n';
@@ -4637,7 +4677,7 @@ void SILDebugScope::print(SILModule &Mod) const {
 void SILSpecializeAttr::print(llvm::raw_ostream &OS) const {
   SILPrintContext Ctx(OS);
   // Print other types as their Swift representation.
-  PrintOptions SubPrinter = PrintOptions::printSIL();
+  PrintOptions options = PrintOptions::printSIL();
   auto exported = isExported() ? "true" : "false";
   auto kind = isPartialSpecialization() ? "partial" : "full";
 
@@ -4671,7 +4711,7 @@ void SILSpecializeAttr::print(llvm::raw_ostream &OS) const {
         requirements,
         [&](Requirement req) {
           if (!genericSig) {
-            req.print(OS, SubPrinter);
+            req.print(OS, options);
             return;
           }
 
@@ -4689,13 +4729,15 @@ void SILSpecializeAttr::print(llvm::raw_ostream &OS) const {
           if (req.getKind() != RequirementKind::Layout) {
             auto SecondTy = genericSig->getSugaredType(req.getSecondType());
             Requirement ReqWithDecls(req.getKind(), FirstTy, SecondTy);
-            ReqWithDecls.print(OS, SubPrinter);
+            ReqWithDecls.print(OS, options);
           } else {
             Requirement ReqWithDecls(req.getKind(), FirstTy,
                                      req.getLayoutConstraint());
-            auto SubPrinterCopy = SubPrinter;
-            SubPrinterCopy.PrintInternalLayoutName = erased;
-            ReqWithDecls.print(OS, SubPrinterCopy);
+
+            PrintOptions::OverrideScope scope(options);
+            OVERRIDE_PRINT_OPTION(scope, PrintInternalLayoutName, erased);
+
+            ReqWithDecls.print(OS, options);
           }
         },
         [&] { OS << ", "; });
diff --git a/lib/SIL/IR/SILSymbolVisitor.cpp b/lib/SIL/IR/SILSymbolVisitor.cpp
index b45b48d7202ad..550290d51e589 100644
--- a/lib/SIL/IR/SILSymbolVisitor.cpp
+++ b/lib/SIL/IR/SILSymbolVisitor.cpp
@@ -472,7 +472,7 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
 
   void visitAbstractFunctionDecl(AbstractFunctionDecl *AFD) {
     // Add exported prespecialized symbols.
-    for (auto *attr : AFD->getAttrs().getAttributes<SpecializeAttr>()) {
+    for (auto *attr : AFD->getAttrs().getAttributes<AbstractSpecializeAttr>()) {
       if (!attr->isExported())
         continue;
 
@@ -569,7 +569,7 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
 
   void visitAbstractStorageDecl(AbstractStorageDecl *ASD) {
     // Add the property descriptor if the decl needs it.
-    if (ASD->exportsPropertyDescriptor()) {
+    if (ASD->getPropertyDescriptorGenericSignature()) {
       Visitor.addPropertyDescriptor(ASD);
     }
 
@@ -621,6 +621,8 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
       if (initInfo.hasInitFromWrappedValue() && !VD->isStatic()) {
         addFunction(SILDeclRef(
             VD, SILDeclRef::Kind::PropertyWrapperBackingInitializer));
+        addFunction(
+            SILDeclRef(VD, SILDeclRef::Kind::PropertyWrappedFieldInitAccessor));
       }
     }
     visitAbstractStorageDecl(VD);
@@ -804,6 +806,7 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
     case DeclKind::PostfixOperator:
     case DeclKind::Macro:
     case DeclKind::MacroExpansion:
+    case DeclKind::Using:
       return false;
     case DeclKind::Missing:
       llvm_unreachable("missing decl should not show up here");
@@ -835,7 +838,6 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
                   V.Ctx.getOpts().WitnessMethodElimination} {}
 
         void addMethod(SILDeclRef declRef) {
-          // TODO: alternatively maybe prevent adding distributed thunk here rather than inside those?
           if (Resilient || WitnessMethodElimination) {
             Visitor.addDispatchThunk(declRef);
             Visitor.addMethodDescriptor(declRef);
@@ -852,8 +854,8 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
           }
         }
 
-        void addAssociatedType(AssociatedType associatedType) {
-          Visitor.addAssociatedTypeDescriptor(associatedType.getAssociation());
+        void addAssociatedType(AssociatedTypeDecl *assocType) {
+          Visitor.addAssociatedTypeDescriptor(assocType);
         }
 
         void addProtocolConformanceDescriptor() {
@@ -917,6 +919,7 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
   UNINTERESTING_DECL(PrecedenceGroup)
   UNINTERESTING_DECL(TopLevelCode)
   UNINTERESTING_DECL(Value)
+  UNINTERESTING_DECL(Using)
 
 #undef UNINTERESTING_DECL
 };
diff --git a/lib/SIL/IR/SILType.cpp b/lib/SIL/IR/SILType.cpp
index f12c27d474297..9062c96d8fb0e 100644
--- a/lib/SIL/IR/SILType.cpp
+++ b/lib/SIL/IR/SILType.cpp
@@ -120,18 +120,18 @@ SILType SILType::getOpaqueIsolationType(const ASTContext &C) {
 bool SILType::isTrivial(const SILFunction &F) const {
   auto contextType = hasTypeParameter() ? F.mapTypeIntoContext(*this) : *this;
   
-  return F.getTypeLowering(contextType).isTrivial();
+  return F.getTypeProperties(contextType).isTrivial();
 }
 
 bool SILType::isOrContainsRawPointer(const SILFunction &F) const {
   auto contextType = hasTypeParameter() ? F.mapTypeIntoContext(*this) : *this;
-  return F.getTypeLowering(contextType).isOrContainsRawPointer();
+  return F.getTypeProperties(contextType).isOrContainsRawPointer();
 }
 
 bool SILType::isNonTrivialOrContainsRawPointer(const SILFunction *f) const {
   auto contextType = hasTypeParameter() ? f->mapTypeIntoContext(*this) : *this;
-  const TypeLowering &tyLowering = f->getTypeLowering(contextType);
-  bool result = !tyLowering.isTrivial() || tyLowering.isOrContainsRawPointer();
+  auto props = f->getTypeProperties(contextType);
+  bool result = !props.isTrivial() || props.isOrContainsRawPointer();
   assert((result || !isFunctionTypeWithContext()) &&
          "a function type with context must either be non trivial or marked as containing a pointer");
   return result;
@@ -139,12 +139,12 @@ bool SILType::isNonTrivialOrContainsRawPointer(const SILFunction *f) const {
 
 bool SILType::isOrContainsPack(const SILFunction &F) const {
   auto contextType = hasTypeParameter() ? F.mapTypeIntoContext(*this) : *this;
-  return F.getTypeLowering(contextType).isOrContainsPack();
+  return F.getTypeProperties(contextType).isOrContainsPack();
 }
 
 bool SILType::isEmpty(const SILFunction &F) const {
   // Infinite types are never empty.
-  if (F.getTypeLowering(*this).getRecursiveProperties().isInfinite()) {
+  if (F.getTypeProperties(*this).isInfinite()) {
     return false;
   }
   
@@ -199,8 +199,7 @@ bool SILType::isNoReturnFunction(SILModule &M,
 
 Lifetime SILType::getLifetime(const SILFunction &F) const {
   auto contextType = hasTypeParameter() ? F.mapTypeIntoContext(*this) : *this;
-  const auto &lowering = F.getTypeLowering(contextType);
-  auto properties = lowering.getRecursiveProperties();
+  auto properties = F.getTypeProperties(contextType);
   if (properties.isTrivial())
     return Lifetime::None;
   return properties.isLexical() ? Lifetime::Lexical : Lifetime::EagerMove;
@@ -462,7 +461,7 @@ bool SILType::isAddressOnly(const SILFunction &F) const {
 
 bool SILType::isFixedABI(const SILFunction &F) const {
   auto contextType = hasTypeParameter() ? F.mapTypeIntoContext(*this) : *this;
-  return F.getTypeLowering(contextType).isFixedABI();
+  return F.getTypeProperties(contextType).isFixedABI();
 }
 
 SILType SILType::substGenericArgs(SILModule &M, SubstitutionMap SubMap,
@@ -656,10 +655,19 @@ SILResultInfo::getOwnershipKind(SILFunction &F,
   case ResultConvention::Owned:
     return OwnershipKind::Owned;
   case ResultConvention::Unowned:
+    // We insert a retain right after the call returning an unowned value in
+    // OwnershipModelEliminator. So treat the result as owned.
+    if (IsTrivial)
+      return OwnershipKind::None;
+    return OwnershipKind::Owned;
   case ResultConvention::UnownedInnerPointer:
     if (IsTrivial)
       return OwnershipKind::None;
     return OwnershipKind::Unowned;
+  case ResultConvention::GuaranteedAddress:
+    return OwnershipKind::None;
+  case ResultConvention::Guaranteed:
+    return OwnershipKind::Guaranteed;
   }
 
   llvm_unreachable("Unhandled ResultConvention in switch.");
@@ -671,7 +679,7 @@ SILModuleConventions::SILModuleConventions(SILModule &M)
 bool SILModuleConventions::isReturnedIndirectlyInSIL(SILType type,
                                                      SILModule &M) {
   if (SILModuleConventions(M).loweredAddresses) {
-    return M.Types.getTypeLowering(type, TypeExpansionContext::minimal())
+    return M.Types.getTypeProperties(type, TypeExpansionContext::minimal())
         .isAddressOnly();
   }
 
@@ -680,7 +688,7 @@ bool SILModuleConventions::isReturnedIndirectlyInSIL(SILType type,
 
 bool SILModuleConventions::isPassedIndirectlyInSIL(SILType type, SILModule &M) {
   if (SILModuleConventions(M).loweredAddresses) {
-    return M.Types.getTypeLowering(type, TypeExpansionContext::minimal())
+    return M.Types.getTypeProperties(type, TypeExpansionContext::minimal())
         .isAddressOnly();
   }
 
@@ -689,7 +697,7 @@ bool SILModuleConventions::isPassedIndirectlyInSIL(SILType type, SILModule &M) {
 
 bool SILModuleConventions::isThrownIndirectlyInSIL(SILType type, SILModule &M) {
   if (SILModuleConventions(M).loweredAddresses) {
-    return M.Types.getTypeLowering(type, TypeExpansionContext::minimal())
+    return M.Types.getTypeProperties(type, TypeExpansionContext::minimal())
         .isAddressOnly();
   }
 
@@ -706,6 +714,39 @@ bool SILFunctionType::isNoReturnFunction(SILModule &M,
   return false;
 }
 
+bool SILFunctionType::isAddressable(unsigned paramIdx, SILFunction *caller) {
+  return isAddressable(paramIdx, caller->getModule(),
+                       caller->getGenericEnvironment(),
+                       caller->getModule().Types,
+                       caller->getTypeExpansionContext());
+}
+
+// 'genericEnv' may be null.
+bool SILFunctionType::isAddressable(unsigned paramIdx, SILModule &module,
+                                    GenericEnvironment *genericEnv,
+                                    Lowering::TypeConverter &typeConverter,
+                                    TypeExpansionContext expansion) {
+  SILParameterInfo paramInfo = getParameters()[paramIdx];
+  for (auto &depInfo : getLifetimeDependencies()) {
+    auto *addressableIndices = depInfo.getAddressableIndices();
+    if (addressableIndices && addressableIndices->contains(paramIdx)) {
+      return true;
+    }
+    auto *condAddressableIndices = depInfo.getConditionallyAddressableIndices();
+    if (condAddressableIndices && condAddressableIndices->contains(paramIdx)) {
+      CanType argType = paramInfo.getArgumentType(module, this, expansion);
+      CanType contextType = genericEnv
+        ? genericEnv->mapTypeIntoContext(argType)->getCanonicalType()
+        : argType;
+      assert(!contextType->hasTypeParameter());
+      if (typeConverter.getTypeProperties(contextType, expansion)
+            .isAddressableForDependencies())
+        return true;
+    }
+  }
+  return false;
+}
+
 #ifndef NDEBUG
 static bool areOnlyAbstractionDifferent(CanType type1, CanType type2) {
   assert(type1->isLegalSILType());
@@ -1151,8 +1192,8 @@ bool SILType::isMarkedAsImmortal() const {
 bool SILType::isAddressableForDeps(const SILFunction &function) const {
   auto contextType =
     hasTypeParameter() ? function.mapTypeIntoContext(*this) : *this;
-  auto &tl = function.getTypeLowering(contextType);
-  return tl.getRecursiveProperties().isAddressableForDependencies();
+  auto properties = function.getTypeProperties(contextType);
+  return properties.isAddressableForDependencies();
 }
 
 intptr_t SILType::getFieldIdxOfNominalType(StringRef fieldName) const {
@@ -1207,7 +1248,7 @@ SILType SILType::addingMoveOnlyWrapperToBoxedType(const SILFunction *fn) {
   auto oldField = oldLayout->getFields()[0];
   if (oldField.getLoweredType()->is<SILMoveOnlyWrappedType>())
     return *this;
-  assert(!oldField.getLoweredType()->isNoncopyable() &&
+  assert(oldField.getLoweredType()->isCopyable() &&
          "Cannot moveonlywrapped in a moveonly type");
   auto newField =
       SILField(SILMoveOnlyWrappedType::get(oldField.getLoweredType()),
diff --git a/lib/SIL/IR/SILTypeSubstitution.cpp b/lib/SIL/IR/SILTypeSubstitution.cpp
index 6c2cee5788cb4..dab536f664c83 100644
--- a/lib/SIL/IR/SILTypeSubstitution.cpp
+++ b/lib/SIL/IR/SILTypeSubstitution.cpp
@@ -68,20 +68,7 @@ class SILTypeSubstituter :
     if (!typeExpansionContext.shouldLookThroughOpaqueTypeArchetypes())
       return subs;
 
-    return subs.subst([&](SubstitutableType *s) -> Type {
-        return substOpaqueTypesWithUnderlyingTypes(s->getCanonicalType(),
-                                                   typeExpansionContext);
-      }, [&](CanType dependentType,
-             Type conformingReplacementType,
-             ProtocolDecl *conformedProtocol) -> ProtocolConformanceRef {
-        return substOpaqueTypesWithUnderlyingTypes(
-               ProtocolConformanceRef::forAbstract(conformingReplacementType,
-                                                   conformedProtocol),
-               conformingReplacementType->getCanonicalType(),
-               typeExpansionContext);
-      },
-      SubstFlags::SubstituteOpaqueArchetypes |
-      SubstFlags::PreservePackExpansionLevel);
+    return substOpaqueTypesWithUnderlyingTypes(subs, typeExpansionContext);
   }
 
   // Substitute a function type.
@@ -253,11 +240,10 @@ class SILTypeSubstituter :
     auto genericSig = IFS.shouldSubstituteOpaqueArchetypes()
                         ? origType->getInvocationGenericSignature()
                         : nullptr;
-                        
-    extInfo = SILFunctionType::getSubstLifetimeDependencies(genericSig, extInfo,
-                                                            substParams,
-                                                            substYields,
-                                                            substResults);
+
+    extInfo = SILFunctionType::getSubstLifetimeDependencies(
+        genericSig, extInfo, TC.Context, substParams, substYields,
+        substResults);
 
     return SILFunctionType::get(genericSig, extInfo,
                                 origType->getCoroutineKind(),
@@ -282,7 +268,7 @@ class SILTypeSubstituter :
       selfType = next;
     }
 
-    auto substConformance = conformance.subst(selfType, IFS);
+    auto substConformance = conformance.subst(IFS);
 
     // Substitute the underlying conformance of opaque type archetypes if we
     // should look through opaque archetypes.
@@ -292,7 +278,7 @@ class SILTypeSubstituter :
       });
       if (substType->hasOpaqueArchetype()) {
         substConformance = substOpaqueTypesWithUnderlyingTypes(
-            substConformance, substType, typeExpansionContext);
+            substConformance, typeExpansionContext);
       }
     }
 
@@ -434,6 +420,14 @@ class SILTypeSubstituter :
                                          substObjectType));
   }
 
+  /// MoveOnlyWrappedTypes need to have their inner types substituted
+  /// by these rules.
+  CanType visitSILMoveOnlyWrappedType(CanSILMoveOnlyWrappedType origType) {
+    CanType origInnerType = origType->getInnerType();
+    CanType substInnerType = visit(origInnerType);
+    return CanType(SILMoveOnlyWrappedType::get(substInnerType));
+  }
+
   /// Any other type would be a valid type in the AST. Just apply the
   /// substitution on the AST level and then lower that.
   CanType visitType(CanType origType) {
diff --git a/lib/SIL/IR/SILVTable.cpp b/lib/SIL/IR/SILVTable.cpp
index c62e6d4764d00..241e127fb3ba8 100644
--- a/lib/SIL/IR/SILVTable.cpp
+++ b/lib/SIL/IR/SILVTable.cpp
@@ -95,8 +95,7 @@ SILVTable::SILVTable(ClassDecl *c, SILType classType,
                      SerializedKind_t serialized, ArrayRef<Entry> entries)
     : Class(c), classType(classType), SerializedKind(serialized),
       NumEntries(entries.size()) {
-  std::uninitialized_copy(entries.begin(), entries.end(),
-                          getTrailingObjects<Entry>());
+  std::uninitialized_copy(entries.begin(), entries.end(), getTrailingObjects());
 
   // Bump the reference count of functions referenced by this table.
   for (const Entry &entry : getEntries()) {
diff --git a/lib/SIL/IR/SILValue.cpp b/lib/SIL/IR/SILValue.cpp
index 1590ca252a180..8b2231f828cb3 100644
--- a/lib/SIL/IR/SILValue.cpp
+++ b/lib/SIL/IR/SILValue.cpp
@@ -192,11 +192,11 @@ bool ValueBase::isGuaranteedForwarding() const {
   }
   // If not a phi, return false
   auto *phi = dyn_cast<SILPhiArgument>(this);
-  if (!phi || !phi->isPhi()) {
-    return false;
+  if (phi && phi->isPhi()) {
+    return phi->isGuaranteedForwarding();
   }
 
-  return phi->isGuaranteedForwarding();
+  return isBorrowAccessorResult();
 }
 
 bool ValueBase::isBeginApplyToken() const {
@@ -206,6 +206,13 @@ bool ValueBase::isBeginApplyToken() const {
   return result->isBeginApplyToken();
 }
 
+bool ValueBase::isBorrowAccessorResult() const {
+  auto *apply = dyn_cast_or_null<ApplyInst>(getDefiningInstruction());
+  if (!apply)
+    return false;
+  return apply->hasGuaranteedResult() || apply->hasGuaranteedAddressResult();
+}
+
 bool ValueBase::hasDebugTrace() const {
   for (auto *op : getUses()) {
     if (auto *debugValue = dyn_cast<DebugValueInst>(op->getUser())) {
diff --git a/lib/SIL/IR/SILWitnessTable.cpp b/lib/SIL/IR/SILWitnessTable.cpp
index d301f37b9fdb4..3253fde7644e7 100644
--- a/lib/SIL/IR/SILWitnessTable.cpp
+++ b/lib/SIL/IR/SILWitnessTable.cpp
@@ -49,11 +49,19 @@ NominalTypeDecl *SILWitnessTable::getConformingNominal() const {
 }
 
 void SILWitnessTable::addWitnessTable() {
-  // Make sure we have not seen this witness table yet.
-  assert(Mod.WitnessTableMap.find(Conformance) ==
-         Mod.WitnessTableMap.end() && "Attempting to create duplicate "
-         "witness table.");
-  Mod.WitnessTableMap[Conformance] = this;
+  if (isSpecialized()) {
+    // Make sure we have not seen this witness table yet.
+    assert(Mod.specializedWitnessTableMap.find(Conformance) ==
+           Mod.specializedWitnessTableMap.end() && "Attempting to create duplicate "
+           "witness table.");
+    Mod.specializedWitnessTableMap[Conformance] = this;
+  } else {
+    // Make sure we have not seen this witness table yet.
+    assert(Mod.WitnessTableMap.find(cast<RootProtocolConformance>(Conformance)) ==
+           Mod.WitnessTableMap.end() && "Attempting to create duplicate "
+           "witness table.");
+    Mod.WitnessTableMap[cast<RootProtocolConformance>(Conformance)] = this;
+  }
   Mod.witnessTables.push_back(this);
 }
 
@@ -61,7 +69,8 @@ SILWitnessTable *SILWitnessTable::create(
     SILModule &M, SILLinkage Linkage, SerializedKind_t SerializedKind,
     ProtocolConformance *Conformance,
     ArrayRef<SILWitnessTable::Entry> entries,
-    ArrayRef<ConditionalConformance> conditionalConformances) {
+    ArrayRef<ProtocolConformanceRef> conditionalConformances,
+    bool specialized) {
   assert(Conformance && "Cannot create a witness table for a null "
          "conformance.");
 
@@ -74,7 +83,7 @@ SILWitnessTable *SILWitnessTable::create(
   void *buf = M.allocate(sizeof(SILWitnessTable), alignof(SILWitnessTable));
   SILWitnessTable *wt = ::new (buf)
       SILWitnessTable(M, Linkage, SerializedKind, Name.str(), Conformance, entries,
-                      conditionalConformances);
+                      conditionalConformances, specialized);
 
   wt->addWitnessTable();
 
@@ -84,7 +93,8 @@ SILWitnessTable *SILWitnessTable::create(
 
 SILWitnessTable *
 SILWitnessTable::create(SILModule &M, SILLinkage Linkage,
-                        ProtocolConformance *Conformance) {
+                        ProtocolConformance *Conformance,
+                        bool specialized) {
   assert(Conformance && "Cannot create a witness table for a null "
          "conformance.");
 
@@ -95,7 +105,7 @@ SILWitnessTable::create(SILModule &M, SILLinkage Linkage,
   // Allocate the witness table and initialize it.
   void *buf = M.allocate(sizeof(SILWitnessTable), alignof(SILWitnessTable));
   SILWitnessTable *wt = ::new (buf) SILWitnessTable(M, Linkage, Name.str(),
-                                                    Conformance);
+                                                    Conformance, specialized);
 
   wt->addWitnessTable();
 
@@ -106,17 +116,17 @@ SILWitnessTable::create(SILModule &M, SILLinkage Linkage,
 SILWitnessTable::SILWitnessTable(
     SILModule &M, SILLinkage Linkage, SerializedKind_t SerializedKind, StringRef N,
     ProtocolConformance *Conformance, ArrayRef<Entry> entries,
-    ArrayRef<ConditionalConformance> conditionalConformances)
+    ArrayRef<ProtocolConformanceRef> conditionalConformances, bool specialized)
     : Mod(M), Name(N), Linkage(Linkage), Conformance(Conformance), Entries(),
-      ConditionalConformances(), IsDeclaration(true),
+      ConditionalConformances(), IsDeclaration(true), specialized(specialized),
       SerializedKind(SerializedKind) {
   convertToDefinition(entries, conditionalConformances, SerializedKind);
 }
 
 SILWitnessTable::SILWitnessTable(SILModule &M, SILLinkage Linkage, StringRef N,
-                                 ProtocolConformance *Conformance)
+                                 ProtocolConformance *Conformance, bool specialized)
     : Mod(M), Name(N), Linkage(Linkage), Conformance(Conformance), Entries(),
-      ConditionalConformances(), IsDeclaration(true),
+      ConditionalConformances(), IsDeclaration(true), specialized(specialized),
       SerializedKind(IsNotSerialized) {}
 
 SILWitnessTable::~SILWitnessTable() {
@@ -142,7 +152,7 @@ SILWitnessTable::~SILWitnessTable() {
 
 void SILWitnessTable::convertToDefinition(
     ArrayRef<Entry> entries,
-    ArrayRef<ConditionalConformance> conditionalConformances,
+    ArrayRef<ProtocolConformanceRef> conditionalConformances,
     SerializedKind_t serializedKind) {
   assert(isDeclaration() && "Definitions should never call this method.");
   IsDeclaration = false;
diff --git a/lib/SIL/IR/TypeLowering.cpp b/lib/SIL/IR/TypeLowering.cpp
index 2b9c26ea8031f..d90e5d8b357eb 100644
--- a/lib/SIL/IR/TypeLowering.cpp
+++ b/lib/SIL/IR/TypeLowering.cpp
@@ -124,12 +124,12 @@ CaptureKind TypeConverter::getDeclCaptureKind(CapturedValue capture,
                                               TypeExpansionContext expansion) {
   if (auto *expr = capture.getPackElement()) {
     auto contextTy = expr->getType();
-    auto &lowering = getTypeLowering(
+    auto props = getTypeProperties(
         contextTy, TypeExpansionContext::noOpaqueTypeArchetypesSubstitution(
                             expansion.getResilienceExpansion()));
 
-    assert(!contextTy->isNoncopyable() && "Not implemented");
-    if (!lowering.isAddressOnly())
+    assert(contextTy->isCopyable() && "Not implemented");
+    if (!props.isAddressOnly())
       return CaptureKind::Constant;
 
     return CaptureKind::Immutable;
@@ -141,7 +141,7 @@ CaptureKind TypeConverter::getDeclCaptureKind(CapturedValue capture,
          "should not have attempted to directly capture this variable");
 
   auto contextTy = var->getTypeInContext();
-  auto &lowering = getTypeLowering(
+  auto props = getTypeProperties(
       contextTy, TypeExpansionContext::noOpaqueTypeArchetypesSubstitution(
                           expansion.getResilienceExpansion()));
 
@@ -161,7 +161,7 @@ CaptureKind TypeConverter::getDeclCaptureKind(CapturedValue capture,
   // If this is a non-address-only stored 'let' constant, we can capture it
   // by value.  If it is address-only, then we can't load it, so capture it
   // by its address (like a var) instead.
-  if (!var->supportsMutation() && !lowering.isAddressOnly())
+  if (!var->supportsMutation() && !props.isAddressOnly())
       return CaptureKind::Constant;
 
   // In-out parameters are captured by address.
@@ -181,7 +181,7 @@ CaptureKind TypeConverter::getDeclCaptureKind(CapturedValue capture,
 
   // For 'let' constants
   if (!var->supportsMutation()) {
-    assert(getTypeLowering(
+    assert(getTypeProperties(
                var->getTypeInContext(),
                TypeExpansionContext::noOpaqueTypeArchetypesSubstitution(
                    expansion.getResilienceExpansion()))
@@ -196,9 +196,7 @@ CaptureKind TypeConverter::getDeclCaptureKind(CapturedValue capture,
           : CaptureKind::Box);
 }
 
-using RecursiveProperties = TypeLowering::RecursiveProperties;
-
-static RecursiveProperties
+static SILTypeProperties
 classifyType(AbstractionPattern origType, CanType type,
              TypeConverter &TC, TypeExpansionContext expansion);
 
@@ -222,78 +220,78 @@ namespace {
     // The subclass should implement:
     //   // Trivial, fixed-layout, and non-address-only.
     //   RetTy handleTrivial(CanType);
-    //   RetTy handleTrivial(CanType, RecursiveProperties properties);
+    //   RetTy handleTrivial(CanType, SILTypeProperties properties);
     //   // A reference type.
     //   RetTy handleReference(CanType);
-    //   RetTy handleReference(CanType, RecursiveProperties properties);
+    //   RetTy handleReference(CanType, SILTypeProperties properties);
     //   // Non-trivial, move only, loadable
-    //   RetTy handleMoveOnlyReference(CanType, RecursiveProperties properties);
+    //   RetTy handleMoveOnlyReference(CanType, SILTypeProperties properties);
     //   // Non-trivial, move only, address only
-    //   RetTy handleMoveOnlyAddressOnly(CanType, RecursiveProperties
+    //   RetTy handleMoveOnlyAddressOnly(CanType, SILTypeProperties
     //   properties);
     //   // Non-trivial and address-only.
-    //   RetTy handleAddressOnly(CanType, RecursiveProperties properties);
+    //   RetTy handleAddressOnly(CanType, SILTypeProperties properties);
     // and, if it doesn't override handleTupleType,
     //   // An aggregate type that's non-trivial.
-    //   RetTy handleNonTrivialAggregate(CanType, RecursiveProperties
+    //   RetTy handleNonTrivialAggregate(CanType, SILTypeProperties
     //   properties);
     //
     // Alternatively, it can just implement:
-    //   RetTy handle(CanType, RecursiveProperties properties);
+    //   RetTy handle(CanType, SILTypeProperties properties);
 
     /// Handle a trivial, fixed-size, loadable type.
-    RetTy handleTrivial(CanType type, RecursiveProperties properties) {
+    RetTy handleTrivial(CanType type, SILTypeProperties properties) {
       return asImpl().handle(type, properties);
     }
 
-    RetTy handleAddressOnly(CanType type, RecursiveProperties properties) {
+    RetTy handleAddressOnly(CanType type, SILTypeProperties properties) {
       return asImpl().handle(type, properties);
     }
 
     RetTy handleNonTrivialAggregate(CanType type,
-                                    RecursiveProperties properties) {
+                                    SILTypeProperties properties) {
       return asImpl().handle(type, properties);
     }
 
     RetTy handleTrivial(CanType type) {
-      return asImpl().handleTrivial(type, RecursiveProperties::forTrivial());
+      return asImpl().handleTrivial(type, SILTypeProperties::forTrivial());
     }
 
     RetTy handleReference(CanType type) {
-      return handleReference(type, RecursiveProperties::forReference());
+      return handleReference(type, SILTypeProperties::forReference());
     }
 
-    RetTy handleReference(CanType type, RecursiveProperties properties) {
+    RetTy handleReference(CanType type, SILTypeProperties properties) {
       return asImpl().handle(type, properties);
     }
 
     RetTy handleMoveOnlyReference(CanType type,
-                                  RecursiveProperties properties) {
+                                  SILTypeProperties properties) {
       return asImpl().handle(type, properties);
     }
 
     RetTy handleMoveOnlyAddressOnly(CanType type,
-                                    RecursiveProperties properties) {
+                                    SILTypeProperties properties) {
       return asImpl().handle(type, properties);
     }
 
-    RecursiveProperties
+    SILTypeProperties
     mergeIsTypeExpansionSensitive(IsTypeExpansionSensitive_t isSensitive,
-                                  RecursiveProperties props) {
+                                  SILTypeProperties props) {
       if (isSensitive == IsTypeExpansionSensitive)
         props.setTypeExpansionSensitive(isSensitive);
       return props;
     }
 
-    RecursiveProperties mergeHasPack(HasPack_t hasPack,
-                                     RecursiveProperties props) {
+    SILTypeProperties mergeHasPack(HasPack_t hasPack,
+                                     SILTypeProperties props) {
       if (hasPack == HasPack)
         props.setHasPack();
       return props;
     }
 
-    RecursiveProperties applyLifetimeAnnotation(LifetimeAnnotation annotation,
-                                                RecursiveProperties props) {
+    SILTypeProperties applyLifetimeAnnotation(LifetimeAnnotation annotation,
+                                                SILTypeProperties props) {
       switch (annotation) {
       case LifetimeAnnotation::None:
         break;
@@ -307,28 +305,28 @@ namespace {
       return props;
     }
 
-    RecursiveProperties
-    getTrivialRecursiveProperties(IsTypeExpansionSensitive_t isSensitive) {
+    SILTypeProperties
+    getTrivialSILTypeProperties(IsTypeExpansionSensitive_t isSensitive) {
       return mergeIsTypeExpansionSensitive(isSensitive,
-                                           RecursiveProperties::forTrivial());
+                                           SILTypeProperties::forTrivial());
     }
 
-    RecursiveProperties
-    getTrivialOpaqueRecursiveProperties(IsTypeExpansionSensitive_t isSensitive) {
+    SILTypeProperties
+    getTrivialOpaqueSILTypeProperties(IsTypeExpansionSensitive_t isSensitive) {
       return mergeIsTypeExpansionSensitive(isSensitive,
-                                           RecursiveProperties::forTrivial());
+                                           SILTypeProperties::forTrivial());
     }
 
-    RecursiveProperties
-    getReferenceRecursiveProperties(IsTypeExpansionSensitive_t isSensitive) {
+    SILTypeProperties
+    getReferenceSILTypeProperties(IsTypeExpansionSensitive_t isSensitive) {
       return mergeIsTypeExpansionSensitive(isSensitive,
-                                           RecursiveProperties::forReference());
+                                           SILTypeProperties::forReference());
     }
 
-    RecursiveProperties
-    getOpaqueRecursiveProperties(IsTypeExpansionSensitive_t isSensitive) {
+    SILTypeProperties
+    getOpaqueSILTypeProperties(IsTypeExpansionSensitive_t isSensitive) {
       return mergeIsTypeExpansionSensitive(isSensitive,
-                                           RecursiveProperties::forOpaque());
+                                           SILTypeProperties::forOpaque());
     }
 
     RetTy visit(CanType substType, AbstractionPattern origType,
@@ -344,7 +342,7 @@ namespace {
     RetTy visit##TYPE##Type(Can##TYPE##Type type, AbstractionPattern orig,   \
                             IsTypeExpansionSensitive_t isSensitive) {        \
       return asImpl().handle##LOWERING(type,                                 \
-                           get##LOWERING##RecursiveProperties(isSensitive)); \
+                           get##LOWERING##SILTypeProperties(isSensitive)); \
     }
 
     IMPL(BuiltinInteger, Trivial)
@@ -370,11 +368,11 @@ namespace {
       llvm_unreachable("not a real type");
     }
     
-    RecursiveProperties getBuiltinFixedArrayProperties(
+    SILTypeProperties getBuiltinFixedArrayProperties(
                                       CanBuiltinFixedArrayType type,
                                       AbstractionPattern origType,
                                       IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties props;
+      SILTypeProperties props;
       
       // We get most of the type properties from the element type.
       AbstractionPattern origElementType = AbstractionPattern::getOpaque();
@@ -439,7 +437,7 @@ namespace {
     RetTy visitPackExpansionType(CanPackExpansionType type,
                                  AbstractionPattern origType,
                                  IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties props;
+      SILTypeProperties props;
       props.setAddressOnly();
       props.addSubobject(classifyType(origType.getPackExpansionPatternType(),
                                       type.getPatternType(),
@@ -452,8 +450,8 @@ namespace {
     RetTy visitBuiltinRawPointerType(CanBuiltinRawPointerType type,
                                      AbstractionPattern orig,
                                      IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties props = mergeIsTypeExpansionSensitive(isSensitive,
-                                          RecursiveProperties::forRawPointer());
+      SILTypeProperties props = mergeIsTypeExpansionSensitive(isSensitive,
+                                          SILTypeProperties::forRawPointer());
       return asImpl().handleTrivial(type, props);
     }
 
@@ -497,11 +495,11 @@ namespace {
       case AnyFunctionType::Representation::Swift:
       case AnyFunctionType::Representation::Block:
         return asImpl().handleReference(
-            type, getReferenceRecursiveProperties(isSensitive));
+            type, getReferenceSILTypeProperties(isSensitive));
       case AnyFunctionType::Representation::CFunctionPointer:
       case AnyFunctionType::Representation::Thin:
         return asImpl().handleTrivial(
-            type, getTrivialRecursiveProperties(isSensitive));
+            type, getTrivialSILTypeProperties(isSensitive));
       }
       llvm_unreachable("bad function representation");
     }
@@ -518,13 +516,13 @@ namespace {
         return asImpl().visitNormalDifferentiableSILFunctionType(
             type, mergeIsTypeExpansionSensitive(
                       isSensitive,
-                      getNormalDifferentiableSILFunctionTypeRecursiveProperties(
+                      getNormalDifferentiableSILFunctionTypeSILTypeProperties(
                           type, origType)));
       case DifferentiabilityKind::Linear:
         return asImpl().visitLinearDifferentiableSILFunctionType(
             type, mergeIsTypeExpansionSensitive(
                       isSensitive,
-                      getNormalDifferentiableSILFunctionTypeRecursiveProperties(
+                      getNormalDifferentiableSILFunctionTypeSILTypeProperties(
                           type, origType)));
       case DifferentiabilityKind::NonDifferentiable:
         break;
@@ -538,16 +536,16 @@ namespace {
         // TODO: Nonescaping closures should also be move-only to ensure we
         // eliminate copies.
         return asImpl().handleReference(
-            type, getReferenceRecursiveProperties(isSensitive));
+            type, getReferenceSILTypeProperties(isSensitive));
       }
       
       // Contextless function references are trivial types.
       return asImpl().handleTrivial(type,
-                                    getTrivialRecursiveProperties(isSensitive));
+                                    getTrivialSILTypeProperties(isSensitive));
     }
 
-    RecursiveProperties
-    getNormalDifferentiableSILFunctionTypeRecursiveProperties(
+    SILTypeProperties
+    getNormalDifferentiableSILFunctionTypeSILTypeProperties(
         CanSILFunctionType type, AbstractionPattern origType) {
       auto origTy = type->getWithoutDifferentiability();
       // Pass the original type of abstraction pattern to
@@ -567,33 +565,33 @@ namespace {
           AutoDiffDerivativeFunctionKind::VJP, TC,
           LookUpConformanceInModule(), CanGenericSignature(),
           false, origTypeOfAbstraction);
-      RecursiveProperties props;
+      SILTypeProperties props;
       props.addSubobject(classifyType(origType, origTy, TC, Expansion));
       props.addSubobject(classifyType(origType, jvpTy, TC, Expansion));
       props.addSubobject(classifyType(origType, vjpTy, TC, Expansion));
       return props;
     }
 
-    RecursiveProperties
-    getLinearDifferentiableSILFunctionTypeRecursiveProperties(
+    SILTypeProperties
+    getLinearDifferentiableSILFunctionTypeSILTypeProperties(
         CanSILFunctionType type, AbstractionPattern origType) {
       auto origTy = type->getWithoutDifferentiability();
       auto transposeTy = origTy->getAutoDiffTransposeFunctionType(
           type->getDifferentiabilityParameterIndices(), TC,
           LookUpConformanceInModule(), origType.getGenericSignatureOrNull());
-      RecursiveProperties props;
+      SILTypeProperties props;
       props.addSubobject(classifyType(origType, origTy, TC, Expansion));
       props.addSubobject(classifyType(origType, transposeTy, TC, Expansion));
       return props;
     }
 
     RetTy visitNormalDifferentiableSILFunctionType(
-        CanSILFunctionType type, RecursiveProperties props) {
+        CanSILFunctionType type, SILTypeProperties props) {
       return handleAggregateByProperties(type, props);
     }
 
     RetTy visitLinearDifferentiableSILFunctionType(
-        CanSILFunctionType type, RecursiveProperties props) {
+        CanSILFunctionType type, SILTypeProperties props) {
       return handleAggregateByProperties(type, props);
     }
 
@@ -611,7 +609,7 @@ namespace {
                          AbstractionPattern origType,
                          IsTypeExpansionSensitive_t isSensitive) {
       return asImpl().handleTrivial(type,
-                                    getTrivialRecursiveProperties(isSensitive));
+                                    getTrivialSILTypeProperties(isSensitive));
     }
 
     // Dependent types can be lowered according to their corresponding
@@ -623,10 +621,10 @@ namespace {
           origType.isOpaqueFunctionOrOpaqueDerivativeFunction()) {
         if (origType.requiresClass()) {
           return asImpl().handleReference(
-              type, getReferenceRecursiveProperties(isSensitive));
+              type, getReferenceSILTypeProperties(isSensitive));
         } else {
           return asImpl().handleAddressOnly(
-              type, getOpaqueRecursiveProperties(isSensitive));
+              type, getOpaqueSILTypeProperties(isSensitive));
         }
       } else {
         // If the abstraction pattern provides a concrete type, lower as that
@@ -697,14 +695,14 @@ namespace {
                                    AbstractionPattern origType, \
                                    IsTypeExpansionSensitive_t isSensitive) { \
       return asImpl().handleReference(type, \
-                                getReferenceRecursiveProperties(isSensitive)); \
+                                getReferenceSILTypeProperties(isSensitive)); \
     }
 #define SOMETIMES_LOADABLE_CHECKED_REF_STORAGE(Name, ...) \
     RetTy visitLoadable##Name##StorageType(Can##Name##StorageType type, \
                                            AbstractionPattern origType, \
                                      IsTypeExpansionSensitive_t isSensitive) { \
       return asImpl().handleReference(type, \
-                                getReferenceRecursiveProperties(isSensitive)); \
+                                getReferenceSILTypeProperties(isSensitive)); \
     } \
     RetTy visitAddressOnly##Name##StorageType(Can##Name##StorageType type, \
                                               AbstractionPattern origType, \
@@ -735,7 +733,7 @@ namespace {
                                    AbstractionPattern origType, \
                                    IsTypeExpansionSensitive_t isSensitive) { \
       return asImpl().handleTrivial(type, \
-                                  getTrivialRecursiveProperties(isSensitive)); \
+                                  getTrivialSILTypeProperties(isSensitive)); \
     }
 #include "swift/AST/ReferenceStorage.def"
 
@@ -759,22 +757,22 @@ namespace {
       if (LayoutInfo) {
         if (LayoutInfo->isFixedSizeTrivial()) {
           return asImpl().handleTrivial(
-              type, getTrivialOpaqueRecursiveProperties(isSensitive));
+              type, getTrivialOpaqueSILTypeProperties(isSensitive));
         }
 
         if (LayoutInfo->isAddressOnlyTrivial()) {
-          auto properties = getTrivialOpaqueRecursiveProperties(isSensitive);
+          auto properties = getTrivialOpaqueSILTypeProperties(isSensitive);
           properties.setAddressOnly();
           return asImpl().handleAddressOnly(type, properties);
         }
 
         if (LayoutInfo->isRefCounted()) {
           return asImpl().handleReference(
-              type, getReferenceRecursiveProperties(isSensitive));
+              type, getReferenceSILTypeProperties(isSensitive));
         }
       }
       return asImpl().handleAddressOnly(
-          type, getOpaqueRecursiveProperties(isSensitive));
+          type, getOpaqueSILTypeProperties(isSensitive));
     }
 
     RetTy visitExistentialType(CanType type,
@@ -797,11 +795,11 @@ namespace {
       case ExistentialRepresentation::Class:
       case ExistentialRepresentation::Boxed:
         return asImpl().handleReference(
-            type, getReferenceRecursiveProperties(isSensitive));
+            type, getReferenceSILTypeProperties(isSensitive));
       // Existential metatypes are trivial.
       case ExistentialRepresentation::Metatype:
         return asImpl().handleTrivial(
-            type, getTrivialRecursiveProperties(isSensitive));
+            type, getTrivialSILTypeProperties(isSensitive));
       }
 
       llvm_unreachable("Unhandled ExistentialRepresentation in switch.");
@@ -869,7 +867,7 @@ namespace {
     // Tuples depend on their elements.
     RetTy visitTupleType(CanTupleType type, AbstractionPattern origType,
                          IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties props;
+      SILTypeProperties props;
       origType.forEachExpandedTupleElement(type,
           [&](AbstractionPattern origEltType, CanType substEltType,
               const TupleTypeElt &elt) {
@@ -904,7 +902,7 @@ namespace {
                           IsTypeExpansionSensitive_t isSensitive) {
       // Should not be loaded.
       return asImpl().handleReference(
-          type, getReferenceRecursiveProperties(isSensitive));
+          type, getReferenceSILTypeProperties(isSensitive));
     }
 
     RetTy visitSILMoveOnlyWrappedType(CanSILMoveOnlyWrappedType type,
@@ -912,20 +910,20 @@ namespace {
                                       IsTypeExpansionSensitive_t isSensitive) {
       AbstractionPattern innerAbstraction = origType.removingMoveOnlyWrapper();
       CanType innerType = type->getInnerType();
-      auto &lowering =
-          TC.getTypeLowering(innerAbstraction, innerType, Expansion);
-      if (lowering.isAddressOnly()) {
+      auto props =
+          TC.getTypeProperties(innerAbstraction, innerType, Expansion);
+      if (props.isAddressOnly()) {
         return asImpl().handleMoveOnlyAddressOnly(
             type->getCanonicalType(),
-            getOpaqueRecursiveProperties(isSensitive));
+            getOpaqueSILTypeProperties(isSensitive));
       }
 
       return asImpl().handleMoveOnlyReference(
           type->getCanonicalType(),
-          getReferenceRecursiveProperties(isSensitive));
+          getReferenceSILTypeProperties(isSensitive));
     }
 
-    RetTy handleAggregateByProperties(CanType type, RecursiveProperties props) {
+    RetTy handleAggregateByProperties(CanType type, SILTypeProperties props) {
       if (props.isAddressOnly()) {
         return asImpl().handleAddressOnly(type, props);
       }
@@ -938,25 +936,25 @@ namespace {
   };
 
   class TypeClassifier :
-      public TypeClassifierBase<TypeClassifier, RecursiveProperties> {
+      public TypeClassifierBase<TypeClassifier, SILTypeProperties> {
   public:
     TypeClassifier(TypeConverter &TC,
                    TypeExpansionContext Expansion)
         : TypeClassifierBase(TC, Expansion) {}
 
-    RecursiveProperties handle(CanType type, RecursiveProperties properties) {
+    SILTypeProperties handle(CanType type, SILTypeProperties properties) {
       return properties;
     }
 
-    RecursiveProperties
+    SILTypeProperties
     visitAnyClassType(CanType type, AbstractionPattern origType, ClassDecl *D,
                       IsTypeExpansionSensitive_t isSensitive) {
-      // Consult the type lowering.
-      auto &lowering = TC.getTypeLowering(origType, type, Expansion);
-      return handleClassificationFromLowering(type, lowering, isSensitive);
+      // Consult the type properties.
+      auto props = TC.getTypeProperties(origType, type, Expansion);
+      return handleClassificationFromLowering(type, props, isSensitive);
     }
 
-    RecursiveProperties visitAnyEnumType(CanType type,
+    SILTypeProperties visitAnyEnumType(CanType type,
                                          AbstractionPattern origType,
                                          EnumDecl *D,
                                        IsTypeExpansionSensitive_t isSensitive) {
@@ -969,31 +967,31 @@ namespace {
                      isSensitive);
       }
 
-      // Consult the type lowering.
-      auto &lowering = TC.getTypeLowering(origType, type, Expansion);
-      return handleClassificationFromLowering(type, lowering, isSensitive);
+      // Consult the type properties.
+      auto props = TC.getTypeProperties(origType, type, Expansion);
+      return handleClassificationFromLowering(type, props, isSensitive);
     }
 
-    RecursiveProperties visitAnyStructType(CanType type,
+    SILTypeProperties visitAnyStructType(CanType type,
                                            AbstractionPattern origType,
                                            StructDecl *D,
                                        IsTypeExpansionSensitive_t isSensitive) {
-      // Consult the type lowering.
-      auto &lowering = TC.getTypeLowering(origType, type, Expansion);
-      return handleClassificationFromLowering(type, lowering, isSensitive);
+      // Consult the type properties.
+      auto props = TC.getTypeProperties(origType, type, Expansion);
+      return handleClassificationFromLowering(type, props, isSensitive);
     }
 
   private:
-    RecursiveProperties
-    handleClassificationFromLowering(CanType type, const TypeLowering &lowering,
+    SILTypeProperties
+    handleClassificationFromLowering(CanType type,
+                                     SILTypeProperties props,
                                      IsTypeExpansionSensitive_t isSensitive) {
-      return handle(type, mergeIsTypeExpansionSensitive(
-                              isSensitive, lowering.getRecursiveProperties()));
+      return handle(type, mergeIsTypeExpansionSensitive(isSensitive, props));
     }
   };
 } // end anonymous namespace
 
-static RecursiveProperties classifyType(AbstractionPattern origType,
+static SILTypeProperties classifyType(AbstractionPattern origType,
                                         CanType type,
                                         TypeConverter &tc,
                                         TypeExpansionContext expansion) {
@@ -1018,7 +1016,7 @@ namespace {
   /// opaque values are passed by value.
   class LoadableTypeLowering : public TypeLowering {
   protected:
-    LoadableTypeLowering(SILType type, RecursiveProperties properties,
+    LoadableTypeLowering(SILType type, SILTypeProperties properties,
                          IsReferenceCounted_t isRefCounted,
                          TypeExpansionContext forExpansion)
       : TypeLowering(type, properties, isRefCounted, forExpansion) {}
@@ -1046,7 +1044,7 @@ namespace {
   /// A class for trivial, fixed-layout, loadable types.
   class TrivialTypeLowering final : public LoadableTypeLowering {
   public:
-    TrivialTypeLowering(SILType type, RecursiveProperties properties,
+    TrivialTypeLowering(SILType type, SILTypeProperties properties,
                         TypeExpansionContext forExpansion)
       : LoadableTypeLowering(type, properties, IsNotReferenceCounted,
                              forExpansion) {
@@ -1144,7 +1142,7 @@ namespace {
   class NonTrivialLoadableTypeLowering : public LoadableTypeLowering {
   public:
     NonTrivialLoadableTypeLowering(SILType type,
-                                   RecursiveProperties properties,
+                                   SILTypeProperties properties,
                                    IsReferenceCounted_t isRefCounted,
                                    TypeExpansionContext forExpansion)
       : LoadableTypeLowering(type, properties, isRefCounted, forExpansion) {
@@ -1286,7 +1284,7 @@ namespace {
       const = 0;
     
   public:
-    LoadableAggTypeLowering(CanType type, RecursiveProperties properties,
+    LoadableAggTypeLowering(CanType type, SILTypeProperties properties,
                             TypeExpansionContext forExpansion)
       : NonTrivialLoadableTypeLowering(SILType::getPrimitiveObjectType(type),
                                        properties, IsNotReferenceCounted,
@@ -1431,7 +1429,7 @@ namespace {
     using Super = LoadableAggTypeLowering<LoadableTupleTypeLowering, unsigned>;
 
   public:
-    LoadableTupleTypeLowering(CanType type, RecursiveProperties properties,
+    LoadableTupleTypeLowering(CanType type, SILTypeProperties properties,
                               TypeExpansionContext forExpansion)
       : LoadableAggTypeLowering(type, properties, forExpansion) {}
 
@@ -1496,7 +1494,7 @@ namespace {
         LoadableAggTypeLowering<LoadableStructTypeLowering, VarDecl *>;
 
   public:
-    LoadableStructTypeLowering(CanType type, RecursiveProperties properties,
+    LoadableStructTypeLowering(CanType type, SILTypeProperties properties,
                                TypeExpansionContext forExpansion)
       : LoadableAggTypeLowering(type, properties, forExpansion) {}
 
@@ -1550,7 +1548,7 @@ namespace {
   /// A lowering for loadable but non-trivial enum types.
   class LoadableEnumTypeLowering final : public NonTrivialLoadableTypeLowering {
   public:
-    LoadableEnumTypeLowering(CanType type, RecursiveProperties properties,
+    LoadableEnumTypeLowering(CanType type, SILTypeProperties properties,
                              TypeExpansionContext forExpansion)
       : NonTrivialLoadableTypeLowering(SILType::getPrimitiveObjectType(type),
                                        properties,
@@ -1658,7 +1656,7 @@ namespace {
 
   public:
     MoveOnlyLoadableStructTypeLowering(CanType type,
-                                       RecursiveProperties properties,
+                                       SILTypeProperties properties,
                                        TypeExpansionContext forExpansion)
         : LoadableAggTypeLowering(type, properties, forExpansion) {}
 
@@ -1727,7 +1725,7 @@ namespace {
       : public NonTrivialLoadableTypeLowering {
   public:
     MoveOnlyLoadableEnumTypeLowering(CanType type,
-                                     RecursiveProperties properties,
+                                     SILTypeProperties properties,
                                      TypeExpansionContext forExpansion)
         : NonTrivialLoadableTypeLowering(SILType::getPrimitiveObjectType(type),
                                          properties, IsNotReferenceCounted,
@@ -1812,7 +1810,7 @@ namespace {
 
   class LeafLoadableTypeLowering : public NonTrivialLoadableTypeLowering {
   public:
-    LeafLoadableTypeLowering(SILType type, RecursiveProperties properties,
+    LeafLoadableTypeLowering(SILType type, SILTypeProperties properties,
                              IsReferenceCounted_t isRefCounted,
                              TypeExpansionContext forExpansion)
       : NonTrivialLoadableTypeLowering(type, properties, isRefCounted,
@@ -1833,12 +1831,12 @@ namespace {
   /// A class for nonspecific loadable nontrivial types.
   class MiscNontrivialTypeLowering : public LeafLoadableTypeLowering {
   public:
-    MiscNontrivialTypeLowering(SILType type, RecursiveProperties properties,
+    MiscNontrivialTypeLowering(SILType type, SILTypeProperties properties,
                           TypeExpansionContext forExpansion)
         : LeafLoadableTypeLowering(type, properties, IsNotReferenceCounted,
                                    forExpansion) {}
 
-    MiscNontrivialTypeLowering(CanType type, RecursiveProperties properties,
+    MiscNontrivialTypeLowering(CanType type, SILTypeProperties properties,
                             TypeExpansionContext forExpansion)
       : MiscNontrivialTypeLowering(SILType::getPrimitiveObjectType(type),
                                    properties, forExpansion)
@@ -1872,7 +1870,7 @@ namespace {
   /// loadable.
   class ReferenceTypeLowering : public LeafLoadableTypeLowering {
   public:
-    ReferenceTypeLowering(SILType type, RecursiveProperties properties,
+    ReferenceTypeLowering(SILType type, SILTypeProperties properties,
                           TypeExpansionContext forExpansion)
         : LeafLoadableTypeLowering(type, properties, IsReferenceCounted,
                                    forExpansion) {}
@@ -1903,7 +1901,7 @@ namespace {
   /// A class for move only types which are non-trivial and loadable
   class MoveOnlyReferenceTypeLowering : public LeafLoadableTypeLowering {
   public:
-    MoveOnlyReferenceTypeLowering(SILType type, RecursiveProperties properties,
+    MoveOnlyReferenceTypeLowering(SILType type, SILTypeProperties properties,
                                   TypeExpansionContext forExpansion)
         : LeafLoadableTypeLowering(type, properties, IsReferenceCounted,
                                    forExpansion) {}
@@ -1937,7 +1935,7 @@ namespace {
   public: \
     Loadable##Name##TypeLowering(SILType type, \
                                  TypeExpansionContext forExpansion, \
-                                 RecursiveProperties props) \
+                                 SILTypeProperties props) \
       : LeafLoadableTypeLowering(type, props, \
                                  IsReferenceCounted, \
                                  forExpansion) {} \
@@ -1962,7 +1960,7 @@ namespace {
   /// A class for non-trivial, address-only types.
   class AddressOnlyTypeLowering : public TypeLowering {
   public:
-    AddressOnlyTypeLowering(SILType type, RecursiveProperties properties,
+    AddressOnlyTypeLowering(SILType type, SILTypeProperties properties,
                             TypeExpansionContext forExpansion)
       : TypeLowering(type, properties, IsNotReferenceCounted,
                      forExpansion) {
@@ -2048,7 +2046,7 @@ namespace {
   class MoveOnlyAddressOnlyTypeLowering : public TypeLowering {
   public:
     MoveOnlyAddressOnlyTypeLowering(SILType type,
-                                    RecursiveProperties properties,
+                                    SILTypeProperties properties,
                                     TypeExpansionContext forExpansion)
         : TypeLowering(type, properties, IsNotReferenceCounted, forExpansion) {
       assert(properties.isAddressOnly());
@@ -2168,7 +2166,7 @@ namespace {
       LoweredType = LoweredType.getAddressType();
     }
 
-    OpaqueValueTypeLowering(SILType type, RecursiveProperties properties,
+    OpaqueValueTypeLowering(SILType type, SILTypeProperties properties,
                             TypeExpansionContext forExpansion)
       : LeafLoadableTypeLowering(type, properties, IsNotReferenceCounted,
                                  forExpansion) {}
@@ -2230,7 +2228,7 @@ namespace {
   class MoveOnlyOpaqueValueTypeLowering : public LeafLoadableTypeLowering {
   public:
     MoveOnlyOpaqueValueTypeLowering(SILType type,
-                                    RecursiveProperties properties,
+                                    SILTypeProperties properties,
                                     TypeExpansionContext forExpansion)
         : LeafLoadableTypeLowering(type, properties, IsNotReferenceCounted,
                                    forExpansion) {}
@@ -2285,35 +2283,39 @@ namespace {
           loweredAddresses(loweredAddresses) {}
 
     TypeLowering *handleTrivial(CanType type) {
-      return handleTrivial(type, RecursiveProperties::forTrivial());
+      return handleTrivial(type, SILTypeProperties::forTrivial());
     }
 
     TypeLowering *handleTrivial(CanType type,
-                                RecursiveProperties properties) {
+                                SILTypeProperties properties) {
+      properties = mergeHasPack(HasPack_t(type->hasAnyPack()), properties);
       auto silType = SILType::getPrimitiveObjectType(type);
       return new (TC) TrivialTypeLowering(silType, properties, Expansion);
     }
 
     TypeLowering *handleReference(CanType type,
-                                  RecursiveProperties properties) {
+                                  SILTypeProperties properties) {
+      properties = mergeHasPack(HasPack_t(type->hasAnyPack()), properties);
       auto silType = SILType::getPrimitiveObjectType(type);
       if (type.isForeignReferenceType() &&
           type->getReferenceCounting() == ReferenceCounting::None)
         return new (TC) TrivialTypeLowering(
-            silType, RecursiveProperties::forTrivial(), Expansion);
+            silType, SILTypeProperties::forTrivial(), Expansion);
 
       return new (TC) ReferenceTypeLowering(silType, properties, Expansion);
     }
 
     TypeLowering *handleMoveOnlyReference(CanType type,
-                                          RecursiveProperties properties) {
+                                          SILTypeProperties properties) {
+      properties = mergeHasPack(HasPack_t(type->hasAnyPack()), properties);
       auto silType = SILType::getPrimitiveObjectType(type);
       return new (TC)
           MoveOnlyReferenceTypeLowering(silType, properties, Expansion);
     }
 
     TypeLowering *handleMoveOnlyAddressOnly(CanType type,
-                                            RecursiveProperties properties) {
+                                            SILTypeProperties properties) {
+      properties = mergeHasPack(HasPack_t(type->hasAnyPack()), properties);
       if (!TC.Context.SILOpts.EnableSILOpaqueValues &&
           !TypeLoweringForceOpaqueValueLowering) {
         auto silType = SILType::getPrimitiveAddressType(type);
@@ -2326,13 +2328,15 @@ namespace {
     }
 
     TypeLowering *handleReference(CanType type) {
+      auto properties = SILTypeProperties::forReference();
+      properties = mergeHasPack(HasPack_t(type->hasAnyPack()), properties);
       auto silType = SILType::getPrimitiveObjectType(type);
-      return new (TC) ReferenceTypeLowering(
-          silType, RecursiveProperties::forReference(), Expansion);
+      return new (TC) ReferenceTypeLowering(silType, properties, Expansion);
     }
 
     TypeLowering *handleAddressOnly(CanType type,
-                                    RecursiveProperties properties) {
+                                    SILTypeProperties properties) {
+      properties = mergeHasPack(HasPack_t(type->hasAnyPack()), properties);
       if (!TC.Context.SILOpts.EnableSILOpaqueValues &&
           !TypeLoweringForceOpaqueValueLowering) {
         auto silType = SILType::getPrimitiveAddressType(type);
@@ -2346,7 +2350,8 @@ namespace {
     }
     
     TypeLowering *handleInfinite(CanType type,
-                                 RecursiveProperties properties) {
+                                 SILTypeProperties properties) {
+      properties = mergeHasPack(HasPack_t(type->hasAnyPack()), properties);
       // Infinite types cannot actually be instantiated, so treat them as
       // opaque for code generation purposes.
       properties.setAddressOnly();
@@ -2362,7 +2367,7 @@ namespace {
       return new (TC) Loadable##Name##TypeLowering( \
                                   SILType::getPrimitiveObjectType(type), \
                                   Expansion, \
-                                getReferenceRecursiveProperties(isSensitive)); \
+                                getReferenceSILTypeProperties(isSensitive)); \
     }
 #define SOMETIMES_LOADABLE_CHECKED_REF_STORAGE(Name, ...) \
     TypeLowering * \
@@ -2372,7 +2377,7 @@ namespace {
       return new (TC) Loadable##Name##TypeLowering( \
                                   SILType::getPrimitiveObjectType(type), \
                                   Expansion, \
-                                getReferenceRecursiveProperties(isSensitive)); \
+                                getReferenceSILTypeProperties(isSensitive)); \
     }
 #include "swift/AST/ReferenceStorage.def"
 
@@ -2394,14 +2399,13 @@ namespace {
     TypeLowering *visitSILPackType(CanSILPackType packType,
                                    AbstractionPattern origType,
                                    IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties properties;
+      SILTypeProperties properties;
       properties.setAddressOnly();
       properties.setHasPack();
       for (auto i : indices(packType.getElementTypes())) {
-        auto &eltLowering =
-          TC.getTypeLowering(packType->getSILElementType(i),
-                             Expansion);
-        properties.addSubobject(eltLowering.getRecursiveProperties());
+        auto eltProps =
+          TC.getTypeProperties(packType->getSILElementType(i), Expansion);
+        properties.addSubobject(eltProps);
       }
       properties = mergeIsTypeExpansionSensitive(isSensitive, properties);
 
@@ -2411,14 +2415,14 @@ namespace {
     TypeLowering *visitPackExpansionType(CanPackExpansionType packExpansionType,
                                          AbstractionPattern origType,
                                          IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties properties;
+      SILTypeProperties properties;
       properties.setAddressOnly();
       properties.setHasPack();
-      auto &patternLowering =
-        TC.getTypeLowering(origType.getPackExpansionPatternType(),
-                           packExpansionType.getPatternType(),
-                           Expansion);
-      properties.addSubobject(patternLowering.getRecursiveProperties());
+      auto patternProps =
+        TC.getTypeProperties(origType.getPackExpansionPatternType(),
+                             packExpansionType.getPatternType(),
+                             Expansion);
+      properties.addSubobject(patternProps);
       properties = mergeIsTypeExpansionSensitive(isSensitive, properties);
 
       return handleAddressOnly(packExpansionType, properties);
@@ -2433,7 +2437,7 @@ namespace {
     TypeLowering *visitTupleType(CanTupleType tupleType,
                                  AbstractionPattern origType,
                                  IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties properties;
+      SILTypeProperties properties;
       origType.forEachExpandedTupleElement(tupleType,
           [&](AbstractionPattern origEltType, CanType substEltType,
               const TupleTypeElt &elt) {
@@ -2455,7 +2459,7 @@ namespace {
     }
 
     bool handleResilience(CanType type, NominalTypeDecl *D,
-                          RecursiveProperties &properties) {
+                          SILTypeProperties &properties) {
       if (D->isResilient()) {
         // If the type is resilient and defined in our module, make a note of
         // that, since our lowering now depends on the resilience expansion.
@@ -2465,7 +2469,7 @@ namespace {
         auto inSameResilienceDomain = D->getModuleContext() == &TC.M ||
                                       D->bypassResilienceInPackage(&TC.M);
         if (inSameResilienceDomain)
-          properties.addSubobject(RecursiveProperties::forResilient());
+          properties.addSubobject(SILTypeProperties::forResilient());
 
         // If the type is in a different module and not in the same package
         // resilience domain (with package-cmo), or if we're using a minimal
@@ -2478,7 +2482,7 @@ namespace {
         if (!inSameResilienceDomain ||
             Expansion.getResilienceExpansion() ==
                                ResilienceExpansion::Minimal) {
-          properties.addSubobject(RecursiveProperties::forOpaque());
+          properties.addSubobject(SILTypeProperties::forOpaque());
           return true;
         }
       }
@@ -2488,8 +2492,8 @@ namespace {
     TypeLowering *visitAnyClassType(CanType classType,
                                     AbstractionPattern origType, ClassDecl *C,
                                     IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties properties =
-          getReferenceRecursiveProperties(isSensitive);
+      SILTypeProperties properties =
+          getReferenceSILTypeProperties(isSensitive);
 
       if (C->getLifetimeAnnotation() == LifetimeAnnotation::EagerMove)
         properties.setLexical(IsNotLexical);
@@ -2503,7 +2507,7 @@ namespace {
                                      AbstractionPattern origType,
                                      StructDecl *D,
                                      IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties properties;
+      SILTypeProperties properties;
 
       properties = mergeIsTypeExpansionSensitive(isSensitive, properties);
 
@@ -2530,6 +2534,11 @@ namespace {
           // that a union contains a pointer.
           if (recordDecl->isOrContainsUnion())
             properties.setIsOrContainsRawPointer();
+            
+          // Treat imported C structs and unions as addressable-for-dependencies
+          // so that Swift lifetime dependencies are more readily interoperable
+          // with pointers in C used for similar purposes.
+          properties.setAddressableForDependencies();
         }
       }
 
@@ -2547,6 +2556,7 @@ namespace {
 
       // If the type has raw storage, it is move-only and address-only.
       if (D->getAttrs().hasAttribute<RawLayoutAttr>()) {
+        properties.setHasRawLayout();
         properties.setAddressOnly();
         properties.setAddressableForDependencies();
         properties.setNonTrivial();
@@ -2621,7 +2631,7 @@ namespace {
                                    AbstractionPattern origType,
                                    EnumDecl *D,
                                    IsTypeExpansionSensitive_t isSensitive) {
-      RecursiveProperties properties;
+      SILTypeProperties properties;
 
       properties = mergeIsTypeExpansionSensitive(isSensitive, properties);
 
@@ -2720,21 +2730,22 @@ namespace {
 
     TypeLowering *
     visitNormalDifferentiableSILFunctionType(CanSILFunctionType type,
-                                             RecursiveProperties props) {
+                                             SILTypeProperties props) {
       return handleAggregateByProperties
           <NormalDifferentiableSILFunctionTypeLowering>(type, props);
     }
 
     TypeLowering *
     visitLinearDifferentiableSILFunctionType(CanSILFunctionType type,
-                                             RecursiveProperties props) {
+                                             SILTypeProperties props) {
       return handleAggregateByProperties
           <LinearDifferentiableSILFunctionTypeLowering>(type, props);
     }
 
     template <class LoadableLoweringClass>
     TypeLowering *handleAggregateByProperties(CanType type,
-                                              RecursiveProperties props) {
+                                              SILTypeProperties props) {
+      props = mergeHasPack(HasPack_t(type->hasAnyPack()), props);
       if (props.isAddressOnly()) {
         return handleAddressOnly(type, props);
       }
@@ -2968,6 +2979,21 @@ TypeConverter::getTypeLowering(AbstractionPattern origType,
   return *lowering;
 }
 
+SILTypeProperties
+TypeConverter::getTypeProperties(Type substType,
+                                 TypeExpansionContext forExpansion) {
+  return getTypeProperties(AbstractionPattern(substType->getCanonicalType()),
+                           substType, forExpansion);
+}
+
+SILTypeProperties
+TypeConverter::getTypeProperties(AbstractionPattern origType,
+                                 Type substType,
+                                 TypeExpansionContext forExpansion) {
+  return getTypeLowering(origType, substType, forExpansion)
+           .getRecursiveProperties();
+}
+
 namespace swift::test {
 static FunctionTest PrintASTTypeLowering(
     "print_ast_type_lowering", [](auto &function, auto &arguments, auto &test) {
@@ -3700,6 +3726,12 @@ TypeConverter::computeLoweredRValueType(TypeExpansionContext forExpansion,
   return visitor.visit(substType);
 }
 
+SILTypeProperties
+TypeConverter::getTypeProperties(SILType type,
+                                 TypeExpansionContext forExpansion) {
+  return getTypeLowering(type, forExpansion).getRecursiveProperties();
+}
+
 const TypeLowering &
 TypeConverter::getTypeLowering(SILType type,
                                TypeExpansionContext forExpansion,
@@ -3960,6 +3992,41 @@ static CanAnyFunctionType getPropertyWrapperBackingInitializerInterfaceType(
                                  resultType, info);
 }
 
+static CanAnyFunctionType getPropertyWrappedFieldInitAccessorInterfaceType(
+    TypeConverter &TC, SILDeclRef wrappedPropertyRef) {
+  auto *wrappedProperty = cast<VarDecl>(wrappedPropertyRef.getDecl());
+  CanType wrappedValueType =
+      wrappedProperty->getPropertyWrapperInitValueInterfaceType()
+          ->getCanonicalType();
+  bool isLocalContext = wrappedProperty->getDeclContext()->isLocalContext();
+  GenericSignature sig =
+      TC.getGenericSignatureWithCapturedEnvironments(wrappedPropertyRef)
+          .genericSig;
+
+  SmallVector<FunctionType::Param, 2> params;
+
+  // Create the wrappedValue param
+  params.emplace_back(
+      wrappedValueType, Identifier(),
+      ParameterTypeFlags().withOwnershipSpecifier(ParamSpecifier::LegacyOwned));
+
+  if (!isLocalContext) {
+    CanType selfType = wrappedProperty->getDeclContext()
+                           ->getSelfInterfaceType()
+                           ->getCanonicalType();
+    // Create the self param
+    params.emplace_back(
+        selfType, Identifier(),
+        ParameterTypeFlags().withOwnershipSpecifier(ParamSpecifier::InOut));
+  }
+
+  CanType resultType = TupleType::getEmpty(TC.Context)->getCanonicalType();
+  AnyFunctionType::CanParamArrayRef paramRef(params);
+  CanAnyFunctionType::ExtInfo extInfo;
+  return CanAnyFunctionType::get(getCanonicalSignatureOrNull(sig), paramRef,
+                                 resultType, extInfo);
+}
+
 /// Get the type of a destructor function.
 static CanAnyFunctionType getDestructorInterfaceType(DestructorDecl *dd,
                                                      bool isDeallocating,
@@ -4203,6 +4270,8 @@ CanAnyFunctionType TypeConverter::makeConstantInterfaceType(SILDeclRef c) {
   case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
   case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
     return getPropertyWrapperBackingInitializerInterfaceType(*this, c);
+  case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
+    return getPropertyWrappedFieldInitAccessorInterfaceType(*this, c);
   case SILDeclRef::Kind::IVarInitializer:
     return getIVarInitDestroyerInterfaceType(cast<ClassDecl>(vd),
                                              c.isForeign, false);
@@ -4245,6 +4314,7 @@ TypeConverter::getGenericSignatureWithCapturedEnvironments(SILDeclRef c) {
       vd->getInnermostDeclContext(), captureInfo);
   }
   case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
+  case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
   case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue: {
     // FIXME: It might be better to compute lowered local captures of
     // the property wrapper generator directly and collapse this into the
@@ -4387,6 +4457,7 @@ TypeConverter::getLoweredLocalCaptures(SILDeclRef fn) {
   case SILDeclRef::Kind::StoredPropertyInitializer:
   case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
   case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
+  case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
     return CaptureInfo::empty();
 
   default:
@@ -4527,6 +4598,8 @@ TypeConverter::getLoweredLocalCaptures(SILDeclRef fn) {
             break;
           case ReadImplKind::Inherited:
             llvm_unreachable("inherited local variable?");
+          case ReadImplKind::Borrow:
+            llvm_unreachable("borrow accessor is not yet implemented");
           }
 
           switch (impl.getWriteImpl()) {
@@ -4551,6 +4624,8 @@ TypeConverter::getLoweredLocalCaptures(SILDeclRef fn) {
             break;
           case WriteImplKind::InheritedWithObservers:
             llvm_unreachable("inherited local variable");
+          case WriteImplKind::Mutate:
+            llvm_unreachable("mutate accessor is not yet implemented");
           }
 
           switch (impl.getReadWriteImpl()) {
@@ -4574,6 +4649,8 @@ TypeConverter::getLoweredLocalCaptures(SILDeclRef fn) {
             break;
           case ReadWriteImplKind::InheritedWithDidSet:
             llvm_unreachable("inherited local variable");
+          case ReadWriteImplKind::Mutate:
+            llvm_unreachable("mutate accessor is not yet implemented");
           }
         }
 
@@ -4676,6 +4753,24 @@ TypeConverter::getLoweredLocalCaptures(SILDeclRef fn) {
 
   collectConstantCaptures(fn);
 
+  // @_inheritActorContext(always) attribute allows implicit
+  // capture of isolation parameter from the context. This
+  // cannot be done as part of computing captures because
+  // isolation is not available at that point because it in
+  // turn depends on captures sometimes.
+  if (auto *closure = fn.getClosureExpr()) {
+    if (closure->alwaysInheritsActorContext()) {
+      auto isolation = closure->getActorIsolation();
+      if (isolation.isActorInstanceIsolated()) {
+        if (auto *var = isolation.getActorInstance()) {
+          recordCapture(CapturedValue(var, /*flags=*/0, SourceLoc()));
+        } else if (auto *actorExpr = isolation.getActorInstanceExpr()) {
+          recordCapture(CapturedValue(actorExpr, /*flags=*/0));
+        }
+      }
+    }
+  }
+
   SmallVector<CapturedValue, 4> resultingCaptures;
   for (auto capturePair : varCaptures) {
     resultingCaptures.push_back(capturePair.second);
@@ -5101,7 +5196,7 @@ TypeConverter::getInterfaceBoxTypeForCapture(ValueDecl *captured,
 
       return paramTy;
     },
-    MakeAbstractConformanceForGenericType(),
+    LookUpConformanceInModule(),
     SubstFlags::PreservePackExpansionLevel)->getCanonicalType());
 }
 
diff --git a/lib/SIL/IR/ValueOwnership.cpp b/lib/SIL/IR/ValueOwnership.cpp
index 77d5c6fbcf9fb..90429b649cdf0 100644
--- a/lib/SIL/IR/ValueOwnership.cpp
+++ b/lib/SIL/IR/ValueOwnership.cpp
@@ -125,6 +125,7 @@ CONSTANT_OWNERSHIP_INST(None, PreviousDynamicFunctionRef)
 CONSTANT_OWNERSHIP_INST(None, GlobalAddr)
 CONSTANT_OWNERSHIP_INST(None, BaseAddrForOffset)
 CONSTANT_OWNERSHIP_INST(None, HasSymbol)
+CONSTANT_OWNERSHIP_INST(None, VectorBaseAddr)
 CONSTANT_OWNERSHIP_INST(None, IndexAddr)
 CONSTANT_OWNERSHIP_INST(None, IndexRawPointer)
 CONSTANT_OWNERSHIP_INST(None, InitEnumDataAddr)
@@ -677,7 +678,10 @@ UNOWNED_OR_NONE_DEPENDING_ON_RESULT(CmpXChg)
 UNOWNED_OR_NONE_DEPENDING_ON_RESULT(AtomicLoad)
 UNOWNED_OR_NONE_DEPENDING_ON_RESULT(ExtractElement)
 UNOWNED_OR_NONE_DEPENDING_ON_RESULT(InsertElement)
+UNOWNED_OR_NONE_DEPENDING_ON_RESULT(Select)
 UNOWNED_OR_NONE_DEPENDING_ON_RESULT(ShuffleVector)
+UNOWNED_OR_NONE_DEPENDING_ON_RESULT(Interleave)
+UNOWNED_OR_NONE_DEPENDING_ON_RESULT(Deinterleave)
 #undef UNOWNED_OR_NONE_DEPENDING_ON_RESULT
 
 #define OWNED_OR_NONE_DEPENDING_ON_RESULT(ID)                                  \
@@ -692,6 +696,7 @@ UNOWNED_OR_NONE_DEPENDING_ON_RESULT(ShuffleVector)
 // fields. The initialized value is immediately consumed by an assignment, so it
 // must be owned.
 OWNED_OR_NONE_DEPENDING_ON_RESULT(ZeroInitializer)
+OWNED_OR_NONE_DEPENDING_ON_RESULT(PrepareInitialization)
 #undef OWNED_OR_NONE_DEPENDING_ON_RESULT
 
 #define BUILTIN(X,Y,Z)
diff --git a/lib/SIL/Parser/ParseSIL.cpp b/lib/SIL/Parser/ParseSIL.cpp
index cfb3e5242280c..3ad66ec3616ac 100644
--- a/lib/SIL/Parser/ParseSIL.cpp
+++ b/lib/SIL/Parser/ParseSIL.cpp
@@ -653,11 +653,10 @@ void SILParser::convertRequirements(ArrayRef<RequirementRepr> From,
                                        Req.getLayoutConstraint());
       To.push_back(ConvertedRequirement);
 
-      if (SILMod.getASTContext().LangOpts.hasFeature(Feature::LayoutPrespecialization)) {
-        if (auto *attributedTy = dyn_cast<AttributedTypeRepr>(Req.getSubjectRepr())) {
-          if (attributedTy->has(TypeAttrKind::NoMetadata)) {
-            typeErasedParams.push_back(Subject);
-          }
+      if (auto *attributedTy =
+              dyn_cast<AttributedTypeRepr>(Req.getSubjectRepr())) {
+        if (attributedTy->has(TypeAttrKind::NoMetadata)) {
+          typeErasedParams.push_back(Subject);
         }
       }
 
@@ -682,10 +681,12 @@ static bool parseDeclSILOptional(
     OptimizationMode *optimizationMode, PerformanceConstraints *perfConstraints,
     bool *isPerformanceConstraint, bool *markedAsUsed, StringRef *section,
     bool *isLet, bool *isWeakImported, bool *needStackProtection,
-    AvailabilityRange *availability, bool *isWithoutActuallyEscapingThunk,
+    bool *isSpecialized, AvailabilityRange *availability,
+    bool *isWithoutActuallyEscapingThunk,
     SmallVectorImpl<std::string> *Semantics,
     SmallVectorImpl<ParsedSpecAttr> *SpecAttrs, ValueDecl **ClangDecl,
-    EffectsKind *MRK, SILParser &SP, SILModule &M) {
+    EffectsKind *MRK, ActorIsolation *actorIsolation, SILParser &SP,
+    SILModule &M) {
   while (SP.P.consumeIf(tok::l_square)) {
     if (isLet && SP.P.Tok.is(tok::kw_let)) {
       *isLet = true;
@@ -725,6 +726,8 @@ static bool parseDeclSILOptional(
       *hasOwnershipSSA = true;
     else if (needStackProtection && SP.P.Tok.getText() == "stack_protection")
       *needStackProtection = true;
+    else if (isSpecialized && SP.P.Tok.getText() == "specialized")
+      *isSpecialized = true;
     else if (isThunk && SP.P.Tok.getText() == "thunk")
       *isThunk = IsThunk;
     else if (isThunk && SP.P.Tok.getText() == "signature_optimized_thunk")
@@ -780,11 +783,33 @@ static bool parseDeclSILOptional(
       *perfConstraints = PerformanceConstraints::NoExistentials;
     else if (perfConstraints && SP.P.Tok.getText() == "no_objc_bridging")
       *perfConstraints = PerformanceConstraints::NoObjCBridging;
+    else if (perfConstraints && SP.P.Tok.getText() == "manual_ownership")
+      *perfConstraints = PerformanceConstraints::ManualOwnership;
     else if (isPerformanceConstraint && SP.P.Tok.getText() == "perf_constraint")
       *isPerformanceConstraint = true;
     else if (markedAsUsed && SP.P.Tok.getText() == "used")
       *markedAsUsed = true;
-    else if (section && SP.P.Tok.getText() == "section") {
+    else if (actorIsolation && SP.P.Tok.getText() == "isolation") {
+      SP.P.consumeToken(tok::identifier);
+      if (SP.P.Tok.getKind() != tok::string_literal) {
+        SP.P.diagnose(SP.P.Tok, diag::expected_in_attribute_list);
+        return true;
+      }
+      StringRef rawString = SP.P.Tok.getText().drop_front().drop_back();
+      // TODO: By using a raw string here, we can perhaps put in a simple string
+      // representation of an actor that can be parsed back. For now this is
+      // just a quick hack so we can write tests.
+      auto optIsolation = ActorIsolation::forSILString(
+          SP.P.Context.getIdentifier(rawString).str());
+      if (!optIsolation) {
+        SP.P.diagnose(SP.P.Tok, diag::expected_in_attribute_list);
+        return true;
+      }
+      *actorIsolation = *optIsolation;
+      SP.P.consumeToken(tok::string_literal);
+      SP.P.parseToken(tok::r_square, diag::expected_in_attribute_list);
+      continue;
+    } else if (section && SP.P.Tok.getText() == "section") {
       SP.P.consumeToken(tok::identifier);
       if (SP.P.Tok.getKind() != tok::string_literal) {
         SP.P.diagnose(SP.P.Tok, diag::expected_in_attribute_list);
@@ -798,7 +823,8 @@ static bool parseDeclSILOptional(
 
       SP.P.parseToken(tok::r_square, diag::expected_in_attribute_list);
       continue;
-    }
+    } else if (inlineStrategy && SP.P.Tok.getText() == "heuristic_always_inline")
+      *inlineStrategy = HeuristicAlwaysInline;
     else if (inlineStrategy && SP.P.Tok.getText() == "always_inline")
       *inlineStrategy = AlwaysInline;
     else if (MRK && SP.P.Tok.getText() == "readnone")
@@ -889,12 +915,15 @@ static bool parseDeclSILOptional(
       SpecAttr.requirements = {};
       SpecAttr.exported = false;
       SpecAttr.kind = SILSpecializeAttr::SpecializationKind::Full;
-      SpecializeAttr *Attr;
+      AbstractSpecializeAttr *Attr;
       StringRef targetFunctionName;
       ModuleDecl *module = nullptr;
+      bool isPublic = false; // In SIL we don't care to disambiguate @specialize
+                             // and @_specialize. We use the "more permissive"
+                             // non-public version when parsing SIL.
       AvailabilityRange availability = AvailabilityRange::alwaysAvailable();
       if (!SP.P.parseSpecializeAttribute(
-              tok::r_square, AtLoc, Loc, Attr, &availability,
+              tok::r_square, AtLoc, Loc, isPublic, Attr, &availability,
               [&targetFunctionName](Parser &P) -> bool {
                 if (P.Tok.getKind() != tok::string_literal) {
                   P.diagnose(P.Tok, diag::expected_in_attribute_list);
@@ -1260,10 +1289,10 @@ bool SILParser::parseSILDottedPathWithoutPound(ValueDecl *&Decl,
     P, FullName[0], /*typeLookup=*/FullName.size() > 1);
   // It is possible that the last member lookup can return multiple lookup
   // results. One example is the overloaded member functions.
-  if (Res.is<ModuleDecl*>()) {
+  if (isa<ModuleDecl *>(Res)) {
     assert(FullName.size() > 1 &&
            "A single module is not a full path to SILDeclRef");
-    auto Mod = Res.get<ModuleDecl*>();
+    auto Mod = cast<ModuleDecl *>(Res);
     values.clear();
     VD = lookupMember(P, ModuleType::get(Mod), FullName[1], Locs[1], values,
                       FullName.size() == 2/*ExpectMultipleResults*/);
@@ -1273,7 +1302,7 @@ bool SILParser::parseSILDottedPathWithoutPound(ValueDecl *&Decl,
                         I == FullName.size() - 1/*ExpectMultipleResults*/);
     }
   } else {
-    VD = Res.get<ValueDecl*>();
+    VD = cast<ValueDecl *>(Res);
     for (unsigned I = 1, E = FullName.size(); I < E; ++I) {
       values.clear();
       VD = lookupMember(P, VD->getInterfaceType(), FullName[I], Locs[I], values,
@@ -1408,6 +1437,9 @@ bool SILParser::parseSILDeclRef(SILDeclRef &Result,
       } else if (!ParseState && Id.str() == "backinginit") {
         Kind = SILDeclRef::Kind::PropertyWrapperBackingInitializer;
         ParseState = 1;
+      } else if (!ParseState && Id.str() == "wrappedfieldinitaccessor") {
+        Kind = SILDeclRef::Kind::PropertyWrappedFieldInitAccessor;
+        ParseState = 1;
       } else if (!ParseState && Id.str() == "projectedvalueinit") {
         Kind = SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue;
         ParseState = 1;
@@ -1874,9 +1906,10 @@ SubstitutionMap getApplySubstitutionsFromParsed(
         // Provide the replacement type.
         return parses[index].replacement;
       },
-      [&](CanType dependentType, Type replacementType,
+      [&](InFlightSubstitution &IFS, Type dependentType,
           ProtocolDecl *proto) -> ProtocolConformanceRef {
-        replacementType = replacementType->getReferenceStorageReferent();
+        auto replacementType = dependentType.subst(IFS)
+            ->getReferenceStorageReferent();
         if (auto conformance = lookupConformance(replacementType, proto))
           return conformance;
 
@@ -2020,32 +2053,6 @@ bool SILParser::parseSILDebugLocation(SILLocation &L, SILBuilder &B) {
   return false;
 }
 
-static bool parseAssignByWrapperMode(AssignByWrapperInst::Mode &Result,
-                                          SILParser &P) {
-  StringRef Str;
-  // If we do not parse '[' ... ']', we have unknown. Set value and return.
-  if (!parseSILOptional(Str, P)) {
-    Result = AssignByWrapperInst::Unknown;
-    return false;
-  }
-
-  // Then try to parse one of our other initialization kinds. We do not support
-  // parsing unknown here so we use that as our fail value.
-  auto Tmp = llvm::StringSwitch<AssignByWrapperInst::Mode>(Str)
-        .Case("init", AssignByWrapperInst::Initialization)
-        .Case("assign", AssignByWrapperInst::Assign)
-        .Case("assign_wrapped_value", AssignByWrapperInst::AssignWrappedValue)
-        .Default(AssignByWrapperInst::Unknown);
-
-  // Thus return true (following the conventions in this file) if we fail.
-  if (Tmp == AssignByWrapperInst::Unknown)
-    return true;
-
-  // Otherwise, assign Result and return false.
-  Result = Tmp;
-  return false;
-}
-
 static bool parseAssignOrInitMode(AssignOrInitInst::Mode &Result,
                                   SILParser &P) {
   StringRef Str;
@@ -3468,6 +3475,12 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
     ResultVal = B.createEndCOWMutation(InstLoc, Val, keepUnique);
     break;
   }
+  case SILInstructionKind::EndCOWMutationAddrInst: {
+    if (parseTypedValueRef(Val, B) || parseSILDebugLocation(InstLoc, B))
+      return true;
+    ResultVal = B.createEndCOWMutationAddr(InstLoc, Val);
+    break;
+  }
   case SILInstructionKind::DestroyNotEscapedClosureInst: {
     bool IsObjcVerificationType = false;
     if (parseSILOptional(IsObjcVerificationType, *this, "objc"))
@@ -4380,12 +4393,7 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
   }
 
   case SILInstructionKind::CheckedCastAddrBranchInst: {
-    auto isolatedConformances = CastingIsolatedConformances::Allow;
-    StringRef attrName;
-    while (parseSILOptional(attrName, *this)) {
-      if (attrName == "prohibit_isolated_conformances")
-        isolatedConformances = CastingIsolatedConformances::Prohibit;
-    }
+    CheckedCastInstOptions options = parseCheckedCastInstOptions(nullptr);
 
     Identifier consumptionKindToken;
     SourceLoc consumptionKindLoc;
@@ -4415,7 +4423,7 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
       return true;
 
     ResultVal = B.createCheckedCastAddrBranch(
-        InstLoc, isolatedConformances, consumptionKind, SourceAddr, SourceType,
+        InstLoc, options, consumptionKind, SourceAddr, SourceType,
         DestAddr, TargetType,
         getBBForReference(SuccessBBName, SuccessBBLoc),
         getBBForReference(FailureBBName, FailureBBLoc));
@@ -4430,28 +4438,18 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
     break;
 
   case SILInstructionKind::UnconditionalCheckedCastAddrInst: {
-    auto isolatedConformances = CastingIsolatedConformances::Allow;
-    StringRef attrName;
-    while (parseSILOptional(attrName, *this)) {
-      if (attrName == "prohibit_isolated_conformances")
-        isolatedConformances = CastingIsolatedConformances::Prohibit;
-    }
+    CheckedCastInstOptions options = parseCheckedCastInstOptions(nullptr);
 
     if (parseSourceAndDestAddress() || parseSILDebugLocation(InstLoc, B))
       return true;
 
     ResultVal = B.createUnconditionalCheckedCastAddr(
-        InstLoc, isolatedConformances, SourceAddr, SourceType,
+        InstLoc, options, SourceAddr, SourceType,
         DestAddr, TargetType);
     break;
   }
   case SILInstructionKind::UnconditionalCheckedCastInst: {
-    auto isolatedConformances = CastingIsolatedConformances::Allow;
-    StringRef attrName;
-    while (parseSILOptional(attrName, *this)) {
-      if (attrName == "prohibit_isolated_conformances")
-        isolatedConformances = CastingIsolatedConformances::Prohibit;
-    }
+    CheckedCastInstOptions options = parseCheckedCastInstOptions(nullptr);
 
     if (parseTypedValueRef(Val, B) || parseVerbatim("to") ||
         parseASTType(TargetType))
@@ -4464,7 +4462,7 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
 
     auto opaque = Lowering::AbstractionPattern::getOpaque();
     ResultVal = B.createUnconditionalCheckedCast(
-        InstLoc, isolatedConformances, Val,
+        InstLoc, options, Val,
         F->getLoweredType(opaque, TargetType), TargetType,
         forwardingOwnership);
     break;
@@ -4472,16 +4470,7 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
 
   case SILInstructionKind::CheckedCastBranchInst: {
     bool isExact = false;
-    auto isolatedConformances = CastingIsolatedConformances::Allow;
-    StringRef attrName;
-    
-    while (parseSILOptional(attrName, *this)) {
-      if (attrName == "prohibit_isolated_conformances")
-        isolatedConformances = CastingIsolatedConformances::Prohibit;
-
-      if (attrName == "exact")
-        isExact = true;
-    }
+    CheckedCastInstOptions options = parseCheckedCastInstOptions(&isExact);
 
     if (parseASTType(SourceType) || parseVerbatim("in"))
       return true;
@@ -4498,7 +4487,7 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
 
     auto opaque = Lowering::AbstractionPattern::getOpaque();
     ResultVal = B.createCheckedCastBranch(
-        InstLoc, isExact, isolatedConformances, Val, SourceType,
+        InstLoc, isExact, options, Val, SourceType,
         F->getLoweredType(opaque, TargetType), TargetType,
         getBBForReference(SuccessBBName, SuccessBBLoc),
         getBBForReference(FailureBBName, FailureBBLoc), forwardingOwnership);
@@ -4645,32 +4634,6 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
     break;
   }
 
-  case SILInstructionKind::AssignByWrapperInst: {
-    SILValue Src, DestAddr, InitFn, SetFn;
-    SourceLoc DestLoc;
-    AssignByWrapperInst::Mode mode;
-
-    if (parseTypedValueRef(Src, B) || parseVerbatim("to") ||
-        parseAssignByWrapperMode(mode, *this) ||
-        parseTypedValueRef(DestAddr, DestLoc, B) ||
-        P.parseToken(tok::comma, diag::expected_tok_in_sil_instr, ",") ||
-        parseVerbatim("init") || parseTypedValueRef(InitFn, B) ||
-        P.parseToken(tok::comma, diag::expected_tok_in_sil_instr, ",") ||
-        parseVerbatim("set") || parseTypedValueRef(SetFn, B) ||
-        parseSILDebugLocation(InstLoc, B))
-      return true;
-
-    if (!DestAddr->getType().isAddress()) {
-      P.diagnose(DestLoc, diag::sil_operand_not_address, "destination",
-                 OpcodeName);
-      return true;
-    }
-
-    ResultVal = B.createAssignByWrapper(InstLoc, Src, DestAddr,
-                                        InitFn, SetFn, mode);
-    break;
-  }
-
   case SILInstructionKind::MoveOnlyWrapperToCopyableAddrInst: {
     SILValue addrVal;
     SourceLoc addrLoc;
@@ -4843,7 +4806,7 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
       } else if (attr == "builtin") {
         setFromBuiltin(true);
       } else {
-        P.diagnose(identLoc, diag::unknown_attribute, attr);
+        P.diagnose(identLoc, diag::unknown_attr_name, attr);
       }
 
       if (!P.consumeIf(tok::r_square))
@@ -5882,6 +5845,12 @@ bool SILParser::parseSpecificSILInstruction(SILBuilder &B,
       ResultVal = B.createIndexAddr(InstLoc, Val, IndexVal, needsStackProtection);
       break;
     }
+    case SILInstructionKind::VectorBaseAddrInst: {
+      if (parseTypedValueRef(Val, B) || parseSILDebugLocation(InstLoc, B))
+        return true;
+      ResultVal = B.createVectorBaseAddr(InstLoc, Val);
+      break;
+    }
     case SILInstructionKind::TailAddrInst: {
       SILValue IndexVal;
       SILType ResultObjTy;
@@ -7045,14 +7014,14 @@ bool SILParser::parseCallInstruction(SILLocation InstLoc,
         llvm::SmallString<64> name;
         llvm::raw_svector_ostream os(name);
         os << isolationCrossing->getCalleeIsolation();
-        P.diagnose(InstLoc.getSourceLoc(), diag::unknown_attribute, name);
+        P.diagnose(InstLoc.getSourceLoc(), diag::unknown_attr_name, name);
       }
       if (isolationCrossing->getCallerIsolation() !=
           ActorIsolation::Unspecified) {
         llvm::SmallString<64> name;
         llvm::raw_svector_ostream os(name);
         os << isolationCrossing->getCalleeIsolation();
-        P.diagnose(InstLoc.getSourceLoc(), diag::unknown_attribute, name);
+        P.diagnose(InstLoc.getSourceLoc(), diag::unknown_attr_name, name);
       }
       return true;
     }
@@ -7327,6 +7296,7 @@ bool SILParserState::parseDeclSIL(Parser &P) {
   SILFunction *DynamicallyReplacedFunction = nullptr;
   SILFunction *AdHocWitnessFunction = nullptr;
   Identifier objCReplacementFor;
+  ActorIsolation actorIsolation;
   if (parseSILLinkage(FnLinkage, P) ||
       parseDeclSILOptional(
           &isTransparent, &isSerialized, &isCanonical, &hasOwnershipSSA,
@@ -7337,8 +7307,9 @@ bool SILParserState::parseDeclSIL(Parser &P) {
           &objCReplacementFor, &specialPurpose, &inlineStrategy,
           &optimizationMode, &perfConstr, &isPerformanceConstraint,
           &markedAsUsed, &section, nullptr, &isWeakImported,
-          &needStackProtection, &availability, &isWithoutActuallyEscapingThunk,
-          &Semantics, &SpecAttrs, &ClangDecl, &MRK, FunctionState, M) ||
+          &needStackProtection, nullptr, &availability,
+          &isWithoutActuallyEscapingThunk, &Semantics, &SpecAttrs, &ClangDecl,
+          &MRK, &actorIsolation, FunctionState, M) ||
       P.parseToken(tok::at_sign, diag::expected_sil_function_name) ||
       P.parseIdentifier(FnName, FnNameLoc, /*diagnoseDollarPrefix=*/false,
                         diag::expected_sil_function_name) ||
@@ -7398,6 +7369,8 @@ bool SILParserState::parseDeclSIL(Parser &P) {
     for (auto &Attr : Semantics) {
       FunctionState.F->addSemanticsAttr(Attr);
     }
+    if (actorIsolation)
+      FunctionState.F->setActorIsolation(actorIsolation);
     // Now that we have a SILFunction parse the body, if present.
 
     bool isDefinition = false;
@@ -7583,16 +7556,18 @@ bool SILParserState::parseSILGlobal(Parser &P) {
   SILType GlobalType;
   SourceLoc NameLoc;
   SerializedKind_t isSerialized = IsNotSerialized;
+  bool isMarkedAsUsed = false;
   bool isLet = false;
 
   SILParser State(P);
   if (parseSILLinkage(GlobalLinkage, P) ||
-      parseDeclSILOptional(nullptr, &isSerialized, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
+      parseDeclSILOptional(nullptr, &isSerialized, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
+                           nullptr, nullptr, nullptr, &isMarkedAsUsed, nullptr,
                            &isLet, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, State, M) ||
+                           nullptr, nullptr, nullptr, nullptr, nullptr, State,
+                           M) ||
       P.parseToken(tok::at_sign, diag::expected_sil_value_name) ||
       P.parseIdentifier(GlobalName, NameLoc, /*diagnoseDollarPrefix=*/false,
                         diag::expected_sil_value_name) ||
@@ -7618,6 +7593,7 @@ bool SILParserState::parseSILGlobal(Parser &P) {
       RegularLocation(NameLoc), VD.value());
 
   GV->setLet(isLet);
+  GV->setMarkedAsUsed(isMarkedAsUsed);
   // Parse static initializer if exists.
   if (State.P.consumeIf(tok::equal) && State.P.consumeIf(tok::l_brace)) {
     SILBuilder B(GV);
@@ -7645,7 +7621,7 @@ bool SILParserState::parseSILProperty(Parser &P) {
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, SP, M))
+                           nullptr, nullptr, nullptr, nullptr, SP, M))
     return true;
   
   ValueDecl *VD;
@@ -7715,7 +7691,7 @@ bool SILParserState::parseSILVTable(Parser &P) {
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, VTableState, M))
+                           nullptr, nullptr, nullptr, nullptr, VTableState, M))
     return true;
 
 
@@ -7732,8 +7708,8 @@ bool SILParserState::parseSILVTable(Parser &P) {
     // Find the class decl.
     llvm::PointerUnion<ValueDecl*, ModuleDecl *> Res =
       lookupTopDecl(P, Name, /*typeLookup=*/true);
-    assert(Res.is<ValueDecl*>() && "Class look-up should return a Decl");
-    ValueDecl *VD = Res.get<ValueDecl*>();
+    assert(isa<ValueDecl *>(Res) && "Class look-up should return a Decl");
+    ValueDecl *VD = cast<ValueDecl *>(Res);
     if (!VD) {
       P.diagnose(Loc, diag::sil_vtable_class_not_found, Name);
       return true;
@@ -7838,7 +7814,8 @@ bool SILParserState::parseSILMoveOnlyDeinit(Parser &parser) {
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, moveOnlyDeinitTableState, M))
+                           nullptr, nullptr, nullptr, nullptr,
+                           moveOnlyDeinitTableState, M))
     return true;
 
   // Parse the class name.
@@ -7851,8 +7828,8 @@ bool SILParserState::parseSILMoveOnlyDeinit(Parser &parser) {
   // Find the nominal decl.
   llvm::PointerUnion<ValueDecl *, ModuleDecl *> res =
       lookupTopDecl(parser, name, /*typeLookup=*/true);
-  assert(res.is<ValueDecl *>() && "Class Nominal-up should return a Decl");
-  ValueDecl *varDecl = res.get<ValueDecl *>();
+  assert(isa<ValueDecl *>(res) && "Class Nominal-up should return a Decl");
+  ValueDecl *varDecl = cast<ValueDecl *>(res);
   if (!varDecl) {
     parser.diagnose(loc, diag::sil_moveonlydeinit_nominal_not_found, name);
     return true;
@@ -7907,8 +7884,8 @@ static ClassDecl *parseClassDecl(Parser &P, SILParser &SP) {
   // Find the protocol decl. The protocol can be imported.
   llvm::PointerUnion<ValueDecl *, ModuleDecl *> Res =
       lookupTopDecl(P, DeclName, /*typeLookup=*/true);
-  assert(Res.is<ValueDecl *>() && "Protocol look-up should return a Decl");
-  ValueDecl *VD = Res.get<ValueDecl *>();
+  assert(isa<ValueDecl *>(Res) && "Protocol look-up should return a Decl");
+  ValueDecl *VD = cast<ValueDecl *>(Res);
   if (!VD) {
     P.diagnose(DeclLoc, diag::sil_default_override_class_not_found, DeclName);
     return nullptr;
@@ -7928,8 +7905,8 @@ static ProtocolDecl *parseProtocolDecl(Parser &P, SILParser &SP) {
   // Find the protocol decl. The protocol can be imported.
   llvm::PointerUnion<ValueDecl*, ModuleDecl *> Res =
     lookupTopDecl(P, DeclName, /*typeLookup=*/true);
-  assert(Res.is<ValueDecl*>() && "Protocol look-up should return a Decl");
-  ValueDecl *VD = Res.get<ValueDecl*>();
+  assert(isa<ValueDecl *>(Res) && "Protocol look-up should return a Decl");
+  ValueDecl *VD = cast<ValueDecl *>(Res);
   if (!VD) {
     P.diagnose(DeclLoc, diag::sil_witness_protocol_not_found, DeclName);
     return nullptr;
@@ -8067,6 +8044,23 @@ ProtocolConformanceRef SILParser::parseProtocolConformance(
   return parseProtocolConformanceHelper(proto, genericSig, genericParams);
 }
 
+CheckedCastInstOptions SILParser::parseCheckedCastInstOptions(bool *isExact) {
+  CheckedCastInstOptions options;
+  StringRef attrName;
+
+  while (parseSILOptional(attrName, *this)) {
+    if (attrName == "prohibit_isolated_conformances") {
+      options = options.withIsolatedConformances(
+                  CastingIsolatedConformances::Prohibit);
+    }
+
+    if (attrName == "exact" && isExact)
+      *isExact = true;
+  }
+
+  return options;
+}
+
 ProtocolConformanceRef SILParser::parseProtocolConformanceHelper(
     ProtocolDecl *&proto,
     GenericSignature witnessSig,
@@ -8157,8 +8151,7 @@ static bool parseSILWitnessTableEntry(
          GenericParamList *witnessParams,
          SILParser &witnessState,
          std::vector<SILWitnessTable::Entry> &witnessEntries,
-         std::vector<SILWitnessTable::ConditionalConformance>
-           &conditionalConformances) {
+         std::vector<ProtocolConformanceRef> &conditionalConformances) {
   Identifier EntryKeyword;
   SourceLoc KeywordLoc;
   if (P.parseIdentifier(EntryKeyword, KeywordLoc,
@@ -8230,7 +8223,6 @@ static bool parseSILWitnessTableEntry(
         P.parseToken(tok::colon, diag::expected_sil_witness_colon))
       return true;
 
-    CanType substType;
     ProtocolConformanceRef conformance;
     if (P.Tok.getText() != "dependent") {
       auto concrete =
@@ -8238,7 +8230,6 @@ static bool parseSILWitnessTableEntry(
       // Ignore invalid and abstract witness entries.
       if (concrete.isInvalid() || !concrete.isConcrete())
         return false;
-      substType = concrete.getConcrete()->getType()->getCanonicalType();
       conformance = concrete;
     } else {
       P.consumeToken();
@@ -8262,7 +8253,6 @@ static bool parseSILWitnessTableEntry(
       if (Ty->hasError())
         return true;
 
-      substType = Ty->getCanonicalType();
       conformance = ProtocolConformanceRef::forAbstract(
           Ty->getCanonicalType(), proto);
     }
@@ -8270,12 +8260,9 @@ static bool parseSILWitnessTableEntry(
     if (EntryKeyword.str() == "associated_conformance")
       witnessEntries.push_back(
           SILWitnessTable::AssociatedConformanceWitness{assocOrSubject,
-                                                        substType,
                                                         conformance});
     else
-      conditionalConformances.push_back(
-          SILWitnessTable::ConditionalConformance{assocOrSubject,
-                                                  conformance});
+      conditionalConformances.push_back(conformance);
 
     return false;
   }
@@ -8367,12 +8354,13 @@ bool SILParserState::parseSILWitnessTable(Parser &P) {
   parseSILLinkage(Linkage, P);
 
   SerializedKind_t isSerialized = IsNotSerialized;
-  if (parseDeclSILOptional(nullptr, &isSerialized, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, WitnessState, M))
+  bool isSpecialized = false;
+  if (parseDeclSILOptional(
+          nullptr, &isSerialized, nullptr, nullptr, nullptr, nullptr, nullptr,
+          nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
+          nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
+          nullptr, nullptr, nullptr, nullptr, &isSpecialized, nullptr, nullptr,
+          nullptr, nullptr, nullptr, nullptr, nullptr, WitnessState, M))
     return true;
 
   // Parse the protocol conformance.
@@ -8385,14 +8373,18 @@ bool SILParserState::parseSILWitnessTable(Parser &P) {
   WitnessState.ContextGenericSig = witnessSig;
   WitnessState.ContextGenericParams = witnessParams;
 
-  // FIXME: should we really allow a specialized or inherited conformance here?
-  RootProtocolConformance *theConformance = nullptr;
-  if (conf.isConcrete())
-    theConformance = conf.getConcrete()->getRootConformance();
+  ProtocolConformance *theConformance = nullptr;
+  if (conf.isConcrete()) {
+    if (isSpecialized) {
+      theConformance = conf.getConcrete();
+    } else {
+      theConformance = conf.getConcrete()->getRootConformance();
+    }
+  }
 
   SILWitnessTable *wt = nullptr;
   if (theConformance) {
-    wt = M.lookUpWitnessTable(theConformance);
+    wt = M.lookUpWitnessTable(theConformance, isSpecialized);
     assert((!wt || wt->isDeclaration()) &&
            "Attempting to create duplicate witness table.");
   }
@@ -8404,7 +8396,7 @@ bool SILParserState::parseSILWitnessTable(Parser &P) {
       Linkage = SILLinkage::PublicExternal;
     // We ignore empty witness table without normal protocol conformance.
     if (!wt && theConformance)
-      wt = SILWitnessTable::create(M, *Linkage, theConformance);
+      wt = SILWitnessTable::create(M, *Linkage, theConformance, isSpecialized);
     return false;
   }
 
@@ -8420,7 +8412,7 @@ bool SILParserState::parseSILWitnessTable(Parser &P) {
   Lexer::SILBodyRAII Tmp(*P.L);
   // Parse the entry list.
   std::vector<SILWitnessTable::Entry> witnessEntries;
-  std::vector<SILWitnessTable::ConditionalConformance> conditionalConformances;
+  std::vector<ProtocolConformanceRef> conditionalConformances;
 
   if (P.Tok.isNot(tok::r_brace)) {
     do {
@@ -8440,7 +8432,7 @@ bool SILParserState::parseSILWitnessTable(Parser &P) {
     Linkage = SILLinkage::Public;
 
   if (!wt)
-    wt = SILWitnessTable::create(M, *Linkage, theConformance);
+    wt = SILWitnessTable::create(M, *Linkage, theConformance, isSpecialized);
   else
     wt->setLinkage(*Linkage);
   wt->convertToDefinition(witnessEntries, conditionalConformances,
@@ -8481,7 +8473,7 @@ bool SILParserState::parseSILDefaultWitnessTable(Parser &P) {
 
   // Parse the entry list.
   std::vector<SILWitnessTable::Entry> witnessEntries;
-  std::vector<SILWitnessTable::ConditionalConformance> conditionalConformances;
+  std::vector<ProtocolConformanceRef> conditionalConformances;
 
   if (P.Tok.isNot(tok::r_brace)) {
     do {
diff --git a/lib/SIL/Parser/SILParser.h b/lib/SIL/Parser/SILParser.h
index 65e9d8771c336..983626a001e95 100644
--- a/lib/SIL/Parser/SILParser.h
+++ b/lib/SIL/Parser/SILParser.h
@@ -411,8 +411,11 @@ class SILParser {
     if (allowed)
       setEnum(existing, value, name, loc);
     else
-      P.diagnose(loc, diag::unknown_attribute, name);
+      P.diagnose(loc, diag::unknown_attr_name, name);
   }
+  
+  /// Parse into checked cast options, such as [prohibit_isolated_conformances].
+  CheckedCastInstOptions parseCheckedCastInstOptions(bool *isExact);
 };
 
 } // namespace swift
diff --git a/lib/SIL/Utils/BasicBlockUtils.cpp b/lib/SIL/Utils/BasicBlockUtils.cpp
index c0653ca3e4035..b375c94d31a64 100644
--- a/lib/SIL/Utils/BasicBlockUtils.cpp
+++ b/lib/SIL/Utils/BasicBlockUtils.cpp
@@ -446,6 +446,16 @@ static FunctionTest DeadEndBlocksTest("dead_end_blocks", [](auto &function,
   }
 #endif
 });
+
+// Arguments:
+// - none
+// Dumps:
+// - message
+static FunctionTest HasAnyDeadEndBlocksTest(
+    "has_any_dead_ends", [](auto &function, auto &arguments, auto &test) {
+      auto deb = test.getDeadEndBlocks();
+      llvm::outs() << (deb->isEmpty() ? "no dead ends\n" : "has dead ends\n");
+    });
 } // end namespace swift::test
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/SIL/Utils/CMakeLists.txt b/lib/SIL/Utils/CMakeLists.txt
index bb4ecf1edf78a..c04a6da4e779c 100644
--- a/lib/SIL/Utils/CMakeLists.txt
+++ b/lib/SIL/Utils/CMakeLists.txt
@@ -13,7 +13,7 @@ target_sources(swiftSIL PRIVATE
   MemAccessUtils.cpp
   MemoryLocations.cpp
   OptimizationRemark.cpp
-  OSSALifetimeCompletion.cpp
+  OSSACompleteLifetime.cpp
   OwnershipLiveness.cpp
   OwnershipUtils.cpp
   PrettyStackTrace.cpp
diff --git a/lib/SIL/Utils/DebugUtils.cpp b/lib/SIL/Utils/DebugUtils.cpp
index 92d5c52514f35..6d0beb0136ef8 100644
--- a/lib/SIL/Utils/DebugUtils.cpp
+++ b/lib/SIL/Utils/DebugUtils.cpp
@@ -34,7 +34,7 @@ bool swift::hasNonTrivialNonDebugTransitiveUsers(
       Worklist.push_back(User);
     }
   } else {
-    auto *I = V.get<SILInstruction *>();
+    auto *I = cast<SILInstruction *>(V);
     SeenInsts.insert(I);
     Worklist.push_back(I);
   }
diff --git a/lib/SIL/Utils/Dominance.cpp b/lib/SIL/Utils/Dominance.cpp
index 6984d33dc8972..bd4b6b66b6c08 100644
--- a/lib/SIL/Utils/Dominance.cpp
+++ b/lib/SIL/Utils/Dominance.cpp
@@ -90,11 +90,12 @@ void DominanceInfo::verify() const {
 
   // And compare.
   if (errorOccurredOnComparison(OtherDT)) {
-    llvm::errs() << "DominatorTree is not up to date!\nComputed:\n";
-    print(llvm::errs());
-    llvm::errs() << "\nActual:\n";
-    OtherDT.print(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "DominatorTree is not up to date!\nComputed:\n";
+      print(out);
+      out << "\nActual:\n";
+      OtherDT.print(out);
+    });
   }
 }
 
@@ -147,11 +148,12 @@ void PostDominanceInfo::verify() const {
 
   // And compare.
   if (errorOccurredOnComparison(OtherDT)) {
-    llvm::errs() << "PostDominatorTree is not up to date!\nComputed:\n";
-    print(llvm::errs());
-    llvm::errs() << "\nActual:\n";
-    OtherDT.print(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "PostDominatorTree is not up to date!\nComputed:\n";
+      print(out);
+      out << "\nActual:\n";
+      OtherDT.print(out);
+    });
   }
 }
 
diff --git a/lib/SIL/Utils/DynamicCasts.cpp b/lib/SIL/Utils/DynamicCasts.cpp
index 230f4ca72e0da..d13d875672ba6 100644
--- a/lib/SIL/Utils/DynamicCasts.cpp
+++ b/lib/SIL/Utils/DynamicCasts.cpp
@@ -93,7 +93,7 @@ static CanType unwrapExistential(CanType e) {
 /// into an existential type by performing a static check
 /// of protocol conformances if it is possible.
 static DynamicCastFeasibility
-classifyDynamicCastToProtocol(CanType source, CanType target,
+classifyDynamicCastToProtocol(SILFunction *function, CanType source, CanType target,
                               bool isWholeModuleOpts) {
   assert(target.isExistentialType() &&
          "target should be an existential type");
@@ -115,8 +115,12 @@ classifyDynamicCastToProtocol(CanType source, CanType target,
 
   // If checkConformance() returns a valid conformance, then all conditional
   // requirements were satisfied.
-  if (checkConformance(source, TargetProtocol))
+  if (auto conformance = checkConformance(source, TargetProtocol)) {
+    if (!matchesActorIsolation(conformance, function))
+      return DynamicCastFeasibility::MaySucceed;
+
     return DynamicCastFeasibility::WillSucceed;
+  }
 
   auto *SourceNominalTy = source.getAnyNominal();
   if (!SourceNominalTy)
@@ -468,7 +472,7 @@ static bool isCFBridgingConversion(CanType sourceFormalType,
 
 /// Try to classify the dynamic-cast relationship between two types.
 DynamicCastFeasibility
-swift::classifyDynamicCast(ModuleDecl *M,
+swift::classifyDynamicCast(SILFunction *function,
                            CanType source,
                            CanType target,
                            bool isSourceTypeExact,
@@ -481,19 +485,20 @@ swift::classifyDynamicCast(ModuleDecl *M,
 
   auto sourceObject = source.getOptionalObjectType();
   auto targetObject = target.getOptionalObjectType();
+  ModuleDecl *M = function->getModule().getSwiftModule();
 
   // A common level of optionality doesn't affect the feasibility,
   // except that we can't fold things to failure because nil inhabits
   // both types.
   if (sourceObject && targetObject) {
-    return atWorst(classifyDynamicCast(M, sourceObject, targetObject),
+    return atWorst(classifyDynamicCast(function, sourceObject, targetObject),
                    DynamicCastFeasibility::MaySucceed);
 
   // Casting to a more optional type follows the same rule unless we
   // know that the source cannot dynamically be an optional value,
   // in which case we'll always just cast and inject into an optional.
   } else if (targetObject) {
-    auto result = classifyDynamicCast(M, source, targetObject,
+    auto result = classifyDynamicCast(function, source, targetObject,
                                       /* isSourceTypeExact */ false,
                                       isWholeModuleOpts);
     if (canDynamicallyStoreOptional(source))
@@ -502,12 +507,12 @@ swift::classifyDynamicCast(ModuleDecl *M,
 
   // Casting to a less-optional type can always fail.
   } else if (sourceObject) {
-    auto result = atBest(classifyDynamicCast(M, sourceObject, target,
+    auto result = atBest(classifyDynamicCast(function, sourceObject, target,
                                              /* isSourceTypeExact */ false,
                                              isWholeModuleOpts),
                          DynamicCastFeasibility::MaySucceed);
     if (target.isExistentialType()) {
-      result = atWorst(result, classifyDynamicCastToProtocol(
+      result = atWorst(result, classifyDynamicCastToProtocol(function,
                                    source, target, isWholeModuleOpts));
     }
     return result;
@@ -522,7 +527,7 @@ swift::classifyDynamicCast(ModuleDecl *M,
     // Check conversions from non-protocol types into protocol types.
     if (!source.isExistentialType() &&
         target.isExistentialType())
-      return classifyDynamicCastToProtocol(source, target,
+      return classifyDynamicCastToProtocol(function, source, target,
                                            isWholeModuleOpts);
 
     // Check conversions from protocol types to non-protocol types.
@@ -552,7 +557,7 @@ swift::classifyDynamicCast(ModuleDecl *M,
       // Hashable is not actually a legal existential type right now, but
       // the check doesn't care about that.
       if (auto hashable = getHashableExistentialType(M)) {
-        return classifyDynamicCastToProtocol(source, hashable,
+        return classifyDynamicCastToProtocol(function, source, hashable,
                                              isWholeModuleOpts);
       }
     }
@@ -589,7 +594,7 @@ swift::classifyDynamicCast(ModuleDecl *M,
 
     if (targetMetatype.isAnyExistentialType() && target->isExistentialType()) {
       auto Feasibility =
-          classifyDynamicCastToProtocol(source, target, isWholeModuleOpts);
+          classifyDynamicCastToProtocol(function, source, target, isWholeModuleOpts);
       // Cast from existential metatype to existential metatype may still
       // succeed, even if we cannot prove anything statically.
       if (Feasibility != DynamicCastFeasibility::WillFail ||
@@ -699,7 +704,7 @@ swift::classifyDynamicCast(ModuleDecl *M,
 
         // Combine the result of prior elements with this element type.
         result = std::max(result,
-                          classifyDynamicCast(M,
+                          classifyDynamicCast(function,
                             sourceElt.getType()->getCanonicalType(),
                             targetElt.getType()->getCanonicalType(),
                             isSourceTypeExact,
@@ -736,7 +741,10 @@ swift::classifyDynamicCast(ModuleDecl *M,
           if (targetClass->isSuperclassOf(sourceClass))
             return DynamicCastFeasibility::WillSucceed;
 
-          return DynamicCastFeasibility::WillFail;
+          // In case of ObjectiveC classes, the runtime type can differ from its
+          // declared type. Therefore a cast between (compile-time) unrelated
+          // classes may succeed at runtime.
+          return DynamicCastFeasibility::MaySucceed;
         }
       }
 
@@ -745,6 +753,12 @@ swift::classifyDynamicCast(ModuleDecl *M,
       if (hierarchyResult != DynamicCastFeasibility::WillFail)
         return hierarchyResult;
 
+      // In case of ObjectiveC classes, the runtime type can differ from its
+      // declared type. Therefore a cast between (compile-time) unrelated
+      // classes may succeed at runtime.
+      if (sourceClass->hasClangNode())
+        return DynamicCastFeasibility::MaySucceed;
+
       // As a backup, consider whether either type is a CF class type
       // with an NS bridged equivalent.
       CanType bridgedSource = getNSBridgedClassOfCFClass(source);
@@ -758,7 +772,7 @@ swift::classifyDynamicCast(ModuleDecl *M,
       // question there.
       if (bridgedSource) source = bridgedSource;
       if (bridgedTarget) target = bridgedTarget;
-      return classifyDynamicCast(M, source, target, false, isWholeModuleOpts);
+      return classifyDynamicCast(function, source, target, false, isWholeModuleOpts);
     }
 
     // Casts from a class into a non-class can never succeed if the target must
@@ -833,7 +847,7 @@ swift::classifyDynamicCast(ModuleDecl *M,
     if (Type ObjCTy = M->getASTContext().getBridgedToObjC(M, source)) {
       // If the bridged ObjC type is known, check if
       // this type can be cast into target type.
-      return classifyDynamicCast(M,
+      return classifyDynamicCast(function,
           ObjCTy->getCanonicalType(),
           target,
           /* isSourceTypeExact */ false, isWholeModuleOpts);
@@ -861,16 +875,16 @@ swift::classifyDynamicCast(ModuleDecl *M,
         // Arrays and sets.
         if (sourceStruct->isArray() || sourceStruct->isSet()) {
           auto valueFeasibility =
-            classifyDynamicCast(M, sourceArgs[0], targetArgs[0]);
+            classifyDynamicCast(function, sourceArgs[0], targetArgs[0]);
           return atWorst(valueFeasibility,
                          DynamicCastFeasibility::MaySucceed);
 
         // Dictionaries.
         } else if (sourceStruct->isDictionary()) {
           auto keyFeasibility =
-            classifyDynamicCast(M, sourceArgs[0], targetArgs[0]);
+            classifyDynamicCast(function, sourceArgs[0], targetArgs[0]);
           auto valueFeasibility =
-            classifyDynamicCast(M, sourceArgs[1], targetArgs[1]);
+            classifyDynamicCast(function, sourceArgs[1], targetArgs[1]);
           return atWorst(atBest(keyFeasibility, valueFeasibility),
                          DynamicCastFeasibility::MaySucceed);
         }
@@ -881,6 +895,25 @@ swift::classifyDynamicCast(ModuleDecl *M,
   return DynamicCastFeasibility::WillFail;
 }
 
+bool swift::matchesActorIsolation(ProtocolConformanceRef conformance, SILFunction *inFunction) {
+  return !conformance.forEachIsolatedConformance([&](ProtocolConformanceRef isolatedConf) -> bool {
+    if (!isolatedConf.isConcrete())
+      return false;
+
+    ActorIsolation isolation = isolatedConf.getConcrete()->getIsolation();
+    if (isolation.isNonisolated())
+      return false;
+
+    if (isolation.isGlobalActor()) {
+      if (auto functionIsolation = inFunction->getActorIsolation()) {
+        if (isolation == functionIsolation.value())
+          return false;
+      }
+    }
+    return true;
+  });
+}
+
 static unsigned getOptionalDepth(CanType type) {
   unsigned depth = 0;
   while (CanType objectType = type.getOptionalObjectType()) {
@@ -1221,7 +1254,7 @@ swift::emitSuccessfulScalarUnconditionalCast(SILBuilder &B, ModuleDecl *M,
                                              CanType sourceFormalType,
                                              CanType targetFormalType,
                                              SILInstruction *existingCast) {
-  assert(classifyDynamicCast(M, sourceFormalType, targetFormalType)
+  assert(classifyDynamicCast(&B.getFunction(), sourceFormalType, targetFormalType)
            == DynamicCastFeasibility::WillSucceed);
 
   // Casts to/from existential types cannot be further improved.
@@ -1258,7 +1291,7 @@ bool swift::emitSuccessfulIndirectUnconditionalCast(
     SILBuilder &B, ModuleDecl *M, SILLocation loc, SILValue src,
     CanType sourceFormalType, SILValue dest, CanType targetFormalType,
     SILInstruction *existingCast) {
-  assert(classifyDynamicCast(M, sourceFormalType, targetFormalType)
+  assert(classifyDynamicCast(&B.getFunction(), sourceFormalType, targetFormalType)
            == DynamicCastFeasibility::WillSucceed);
 
   assert(src->getType().isAddress());
@@ -1289,7 +1322,7 @@ bool swift::emitSuccessfulIndirectUnconditionalCast(
     }
 
     B.createUnconditionalCheckedCastAddr(loc,
-                                         CastingIsolatedConformances::Allow,
+                                         CheckedCastInstOptions(),
                                          src, sourceFormalType,
                                          dest, targetFormalType);
     return true;
@@ -1322,6 +1355,27 @@ bool swift::canSILUseScalarCheckedCastInstructions(SILModule &M,
                                                   targetFormalType);
 }
 
+bool swift::canOptimizeToScalarCheckedCastInstructions(
+    SILFunction *func, CanType sourceType, CanType targetType,
+    CastConsumptionKind consumption) {
+  if (!canSILUseScalarCheckedCastInstructions(func->getModule(), sourceType,
+                                              targetType)) {
+    return false;
+  }
+
+  if (consumption == CastConsumptionKind::CopyOnSuccess) {
+    // If it's a copy-on-success cast, check whether the cast preserves
+    // ownership in ossa. This is needed because the optimization creates a
+    // scalar cast which is a guaranteed forwarding instruction and is valid
+    // only when ownership can be preserved.
+    return !func->hasOwnership() ||
+           doesCastPreserveOwnershipForTypes(func->getModule(), sourceType,
+                                             targetType);
+  }
+
+  return true;
+}
+
 /// Can the given cast be performed by the scalar checked-cast
 /// instructions?
 bool swift::canIRGenUseScalarCheckedCastInstructions(SILModule &M,
@@ -1345,23 +1399,26 @@ bool swift::canIRGenUseScalarCheckedCastInstructions(SILModule &M,
   // bridging, unless we can statically see that the source type inherits
   // NSError.
   
-  // A class-constrained archetype may be bound to NSError, unless it has a
-  // non-NSError superclass constraint. Casts to archetypes thus must always be
-  // indirect.
   if (auto archetype = targetFormalType->getAs<ArchetypeType>()) {
     // Only ever permit this if the source type is a reference type.
     if (!objectType.isAnyClassReferenceType())
       return false;
-    
-    auto super = archetype->getSuperclass();
-    if (super.isNull())
-      return false;
 
-    // A base class constraint that isn't NSError rules out the archetype being
-    // bound to NSError.
     if (M.getASTContext().LangOpts.EnableObjCInterop) {
+      // A class-constrained archetype may be bound to NSError, unless it has a
+      // non-NSError superclass constraint. Casts to archetypes thus must always be
+      // indirect.
+      auto super = archetype->getSuperclass();
+      if (super.isNull())
+        return false;
+
+      // A base class constraint that isn't NSError rules out the archetype being
+      // bound to NSError.
       if (auto nserror = M.Types.getNSErrorType())
          return !super->isEqual(nserror);
+    } else {
+      if (!archetype->requiresClass())
+        return false;
     }
     
     // If NSError wasn't loaded, any base class constraint must not be NSError.
@@ -1395,7 +1452,7 @@ bool swift::canIRGenUseScalarCheckedCastInstructions(SILModule &M,
 /// using a scalar cast operation.
 void swift::emitIndirectConditionalCastWithScalar(
     SILBuilder &B, ModuleDecl *M, SILLocation loc,
-    CastingIsolatedConformances isolatedConformances,
+    CheckedCastInstOptions options,
     CastConsumptionKind consumption,
     SILValue srcAddr, CanType sourceFormalType,
     SILValue destAddr, CanType targetFormalType,
@@ -1434,7 +1491,7 @@ void swift::emitIndirectConditionalCastWithScalar(
   })();
 
   auto *ccb = B.createCheckedCastBranch(
-      loc, /*exact*/ false, isolatedConformances, srcValue, sourceFormalType,
+      loc, /*exact*/ false, options, srcValue, sourceFormalType,
       targetLoweredType, targetFormalType, scalarSuccBB, scalarFailBB,
       TrueCount, FalseCount);
 
diff --git a/lib/SIL/Utils/FieldSensitivePrunedLiveness.cpp b/lib/SIL/Utils/FieldSensitivePrunedLiveness.cpp
index 2bc9ef48d5791..f9f091113b54b 100644
--- a/lib/SIL/Utils/FieldSensitivePrunedLiveness.cpp
+++ b/lib/SIL/Utils/FieldSensitivePrunedLiveness.cpp
@@ -148,6 +148,12 @@ SubElementOffset::computeForAddress(SILValue projectionDerivedFromRoot,
       continue;
     }
 
+    if (auto *uaci =
+            dyn_cast<UncheckedAddrCastInst>(projectionDerivedFromRoot)) {
+      projectionDerivedFromRoot = uaci->getOperand();
+      continue;
+    }
+
     if (auto *sbi = dyn_cast<StoreBorrowInst>(projectionDerivedFromRoot)) {
       projectionDerivedFromRoot = sbi->getDest();
       continue;
diff --git a/lib/SIL/Utils/GenericSpecializationMangler.cpp b/lib/SIL/Utils/GenericSpecializationMangler.cpp
index d4cc51ae2f64e..6b3da8eed20b6 100644
--- a/lib/SIL/Utils/GenericSpecializationMangler.cpp
+++ b/lib/SIL/Utils/GenericSpecializationMangler.cpp
@@ -42,8 +42,9 @@ class AttributeDemangler : public Demangle::Demangler {
                                 NodePointer Parent) {
     DemangleInitRAII state(*this, MangledSpecialization, nullptr);
     if (!parseAndPushNodes()) {
-      llvm::errs() << "Can't demangle: " << MangledSpecialization << '\n';
-      abort();
+      ABORT([&](auto &out) {
+        out << "Can't demangle: " << MangledSpecialization;
+      });
     }
     for (Node *Nd : NodeStack) {
       addChild(Parent, Nd);
@@ -62,8 +63,10 @@ std::string SpecializationMangler::finalize() {
   StringRef FuncName = Function ? Function->getName() : StringRef(FunctionName);
   NodePointer FuncTopLevel = nullptr;
   if (FuncName.starts_with(MANGLING_PREFIX_STR)) {
+    // Demangling can fail, i.e. FuncTopLevel == nullptr, if the user provides
+    // a custom not-demangable `@_silgen_name` (but still containing the "$s"
+    // mangling prefix).
     FuncTopLevel = D.demangleSymbol(FuncName);
-    assert(FuncTopLevel);
   }
   else if (FuncName.starts_with(MANGLING_PREFIX_EMBEDDED_STR)) {
     FuncTopLevel = D.demangleSymbol(FuncName);
@@ -88,14 +91,16 @@ std::string SpecializationMangler::finalize() {
 //===----------------------------------------------------------------------===//
 
 void GenericSpecializationMangler::
-appendSubstitutions(GenericSignature sig, SubstitutionMap subs) {
+appendSubstitutions(GenericSignature calleeSig,
+                    SubstitutionMap calleeSubs,
+                    GenericSignature callerSig) {
   bool First = true;
-  sig->forEachParam([&](GenericTypeParamType *ParamType, bool Canonical) {
+  calleeSig->forEachParam([&](GenericTypeParamType *ParamType, bool Canonical) {
     if (Canonical) {
       auto ty = Type(ParamType);
-      auto substTy = ty.subst(subs);
+      auto substTy = ty.subst(calleeSubs);
       auto canTy = substTy->getCanonicalType();
-      appendType(canTy, nullptr);
+      appendType(canTy, callerSig);
       appendListSeparator(First);
     }
   });
@@ -105,7 +110,7 @@ appendSubstitutions(GenericSignature sig, SubstitutionMap subs) {
 std::string GenericSpecializationMangler::
 manglePrespecialized(GenericSignature sig, SubstitutionMap subs) {
   beginMangling();
-  appendSubstitutions(sig, subs);
+  appendSubstitutions(sig, subs, GenericSignature());
   appendSpecializationOperator("Ts");
   return finalize();
 }
@@ -114,7 +119,7 @@ std::string GenericSpecializationMangler::
 mangleNotReabstracted(SubstitutionMap subs,
                       const SmallBitVector &paramsRemoved) {
   beginMangling();
-  appendSubstitutions(getGenericSignature(), subs);
+  appendSubstitutions(getGenericSignature(), subs, GenericSignature());
   appendOperator("T");
   appendRemovedParams(paramsRemoved);
   appendSpecializationOperator("G");
@@ -125,7 +130,7 @@ std::string GenericSpecializationMangler::
 mangleReabstracted(SubstitutionMap subs, bool alternativeMangling,
                    const SmallBitVector &paramsRemoved) {
   beginMangling();
-  appendSubstitutions(getGenericSignature(), subs);
+  appendSubstitutions(getGenericSignature(), subs, GenericSignature());
   appendOperator("T");
   appendRemovedParams(paramsRemoved);
 
@@ -144,9 +149,10 @@ void GenericSpecializationMangler::appendRemovedParams(const SmallBitVector &par
 }
 
 std::string GenericSpecializationMangler::
-mangleForDebugInfo(GenericSignature sig, SubstitutionMap subs, bool forInlining) {
+mangleForDebugInfo(GenericSignature calleeSig, SubstitutionMap calleeSubs,
+                   GenericSignature callerSig, bool forInlining) {
   beginMangling();
-  appendSubstitutions(sig, subs);
+  appendSubstitutions(calleeSig, calleeSubs, callerSig);
   appendSpecializationOperator(forInlining ? "Ti" : "TG");
   return finalize();
 }
diff --git a/lib/SIL/Utils/InstructionUtils.cpp b/lib/SIL/Utils/InstructionUtils.cpp
index f1e002b0d4a00..e07ff4fc2e8e7 100644
--- a/lib/SIL/Utils/InstructionUtils.cpp
+++ b/lib/SIL/Utils/InstructionUtils.cpp
@@ -48,6 +48,22 @@ SILValue swift::lookThroughOwnershipInsts(SILValue v) {
   }
 }
 
+SILValue swift::lookThroughMoveOnlyCheckerPattern(SILValue value) {
+  auto *bbi = dyn_cast<BeginBorrowInst>(value);
+  if (!bbi) {
+    return value;
+  }
+  auto *muncvi = cast<MarkUnresolvedNonCopyableValueInst>(bbi->getOperand());
+  if (!muncvi) {
+    return value;
+  }
+  auto *cvi = cast<CopyValueInst>(muncvi->getOperand());
+  if (!cvi) {
+    return value;
+  }
+  return cvi->getOperand();
+}
+
 bool swift::visitNonOwnershipUses(SILValue value,
                                   function_ref<bool(Operand *)> visitor) {
   // All ownership insts have a single operand, so a recursive walk is
@@ -439,21 +455,6 @@ SILValue swift::isPartialApplyOfReabstractionThunk(PartialApplyInst *PAI) {
   return Arg;
 }
 
-bool swift::onlyUsedByAssignByWrapper(PartialApplyInst *PAI) {
-  bool usedByAssignByWrapper = false;
-  for (Operand *Op : PAI->getUses()) {
-    SILInstruction *User = Op->getUser();
-    if (isa<AssignByWrapperInst>(User) && Op->getOperandNumber() >= 2) {
-      usedByAssignByWrapper = true;
-      continue;
-    }
-    if (isa<DestroyValueInst>(User))
-      continue;
-    return false;
-  }
-  return usedByAssignByWrapper;
-}
-
 bool swift::onlyUsedByAssignOrInit(PartialApplyInst *PAI) {
   bool usedByAssignOrInit = false;
   for (Operand *Op : PAI->getUses()) {
@@ -567,7 +568,6 @@ RuntimeEffect swift::getRuntimeEffect(SILInstruction *inst, SILType &impactType)
   case SILInstructionKind::CopyableToMoveOnlyWrapperValueInst:
   case SILInstructionKind::MoveOnlyWrapperToCopyableValueInst:
   case SILInstructionKind::UncheckedOwnershipConversionInst:
-  case SILInstructionKind::LoadInst:
   case SILInstructionKind::LoadBorrowInst:
   case SILInstructionKind::BeginBorrowInst:
   case SILInstructionKind::BorrowedFromInst:
@@ -581,6 +581,7 @@ RuntimeEffect swift::getRuntimeEffect(SILInstruction *inst, SILType &impactType)
   case SILInstructionKind::TupleExtractInst:
   case SILInstructionKind::StructInst:
   case SILInstructionKind::StructExtractInst:
+  case SILInstructionKind::VectorBaseAddrInst:
   case SILInstructionKind::RefElementAddrInst:
   case SILInstructionKind::EnumInst:
   case SILInstructionKind::UncheckedEnumDataInst:
@@ -611,7 +612,6 @@ RuntimeEffect swift::getRuntimeEffect(SILInstruction *inst, SILType &impactType)
   case SILInstructionKind::FixLifetimeInst:
   case SILInstructionKind::EndBorrowInst:
   case SILInstructionKind::AssignInst:
-  case SILInstructionKind::AssignByWrapperInst:
   case SILInstructionKind::AssignOrInitInst:
   case SILInstructionKind::MarkFunctionEscapeInst:
   case SILInstructionKind::EndLifetimeInst:
@@ -628,6 +628,7 @@ RuntimeEffect swift::getRuntimeEffect(SILInstruction *inst, SILType &impactType)
   case SILInstructionKind::DifferentiabilityWitnessFunctionInst:
   case SILInstructionKind::IncrementProfilerCounterInst:
   case SILInstructionKind::EndCOWMutationInst:
+  case SILInstructionKind::EndCOWMutationAddrInst:
   case SILInstructionKind::HasSymbolInst:
   case SILInstructionKind::DynamicPackIndexInst:
   case SILInstructionKind::PackPackIndexInst:
@@ -640,6 +641,14 @@ RuntimeEffect swift::getRuntimeEffect(SILInstruction *inst, SILType &impactType)
   case SILInstructionKind::TypeValueInst:
   case SILInstructionKind::IgnoredUseInst:
     return RuntimeEffect::NoEffect;
+
+  case SILInstructionKind::LoadInst: {
+    if (cast<LoadInst>(inst)->getOwnershipQualifier() == LoadOwnershipQualifier::Copy) {
+      return ifNonTrivial(inst->getOperand(0)->getType(),
+                          RuntimeEffect::RefCounting);
+    }
+    return RuntimeEffect::NoEffect;
+  }
       
   case SILInstructionKind::OpenExistentialMetatypeInst:
   case SILInstructionKind::OpenExistentialBoxInst:
@@ -1463,7 +1472,7 @@ bool swift::shouldExpand(SILModule &module, SILType ty) {
   // FIXME: Expansion
   auto expansion = TypeExpansionContext::minimal();
 
-  if (module.Types.getTypeLowering(ty, expansion).isAddressOnly()) {
+  if (module.Types.getTypeProperties(ty, expansion).isAddressOnly()) {
     return false;
   }
   // A move-only-with-deinit type cannot be SROA.
diff --git a/lib/SIL/Utils/MemAccessUtils.cpp b/lib/SIL/Utils/MemAccessUtils.cpp
index 554711f2d2c4f..76a881f9bd7fa 100644
--- a/lib/SIL/Utils/MemAccessUtils.cpp
+++ b/lib/SIL/Utils/MemAccessUtils.cpp
@@ -1402,7 +1402,7 @@ class AccessPathVisitor : public FindAccessVisitorImpl<AccessPathVisitor> {
           AccessPath::Index::forSubObjectProjection(projIdx.Index));
     } else {
       // Ignore everything in getAccessProjectionOperand that is an access
-      // projection with no affect on the access path.
+      // projection with no effect on the access path.
       assert(isa<OpenExistentialAddrInst>(projectedAddr) ||
              isa<InitEnumDataAddrInst>(projectedAddr) ||
              isa<UncheckedTakeEnumDataAddrInst>(projectedAddr)
@@ -1416,7 +1416,8 @@ class AccessPathVisitor : public FindAccessVisitorImpl<AccessPathVisitor> {
              // copyable_to_moveonlywrapper_addr, we just look through it when
              // we see it
              || isa<MoveOnlyWrapperToCopyableAddrInst>(projectedAddr) ||
-             isa<CopyableToMoveOnlyWrapperAddrInst>(projectedAddr));
+             isa<CopyableToMoveOnlyWrapperAddrInst>(projectedAddr) ||
+             isGuaranteedAddressReturn(projectedAddr));
     }
     return sourceAddr->get();
   }
@@ -1437,7 +1438,7 @@ AccessPathWithBase AccessPathWithBase::computeInScope(SILValue address) {
 }
 
 bool swift::visitProductLeafAccessPathNodes(
-    SILValue address, TypeExpansionContext tec, SILModule &module,
+    SILValue address, TypeExpansionContext tec, SILFunction &function,
     std::function<void(AccessPath::PathNode, SILType)> visitor) {
   auto rootPath = AccessPath::compute(address);
   if (!rootPath.isValid()) {
@@ -1461,7 +1462,8 @@ bool swift::visitProductLeafAccessPathNodes(
         visitor(AccessPath::PathNode(node), silType);
         continue;
       }
-      if (decl->isCxxNonTrivial()) {
+      if (decl->isCxxNonTrivial() || !silType.isEscapable(function) ||
+          silType.isMoveOnly()) {
         visitor(AccessPath::PathNode(node), silType);
         continue;
       }
@@ -1469,7 +1471,8 @@ bool swift::visitProductLeafAccessPathNodes(
       for (auto *field : decl->getStoredProperties()) {
         auto *fieldNode = node->getChild(index);
         worklist.push_back(
-            {silType.getFieldType(field, module, tec), fieldNode});
+            {silType.getFieldType(field, function.getModule(), tec),
+             fieldNode});
         ++index;
       }
     } else {
@@ -1980,7 +1983,7 @@ AccessPathDefUseTraversal::visitSingleValueUser(SingleValueInstruction *svi,
     return IgnoredUse;
 
   // open_existential_addr and unchecked_take_enum_data_addr are classified as
-  // access projections, but they also modify memory. Both see through them and
+  // access projections, but they also modify memory. Both look through them and
   // also report them as uses.
   case SILInstructionKind::OpenExistentialAddrInst:
   case SILInstructionKind::UncheckedTakeEnumDataAddrInst:
@@ -2027,6 +2030,9 @@ bool AccessPathDefUseTraversal::visitUser(DFSEntry dfs) {
         && visitSingleValueUser(svi, dfs) == IgnoredUse) {
       return true;
     }
+    if (isGuaranteedAddressReturn(svi)) {
+      pushUsers(svi, dfs);
+    }
   }
   if (auto *sbi = dyn_cast<StoreBorrowInst>(use->getUser())) {
     if (use->get() == sbi->getDest()) {
@@ -2036,6 +2042,7 @@ bool AccessPathDefUseTraversal::visitUser(DFSEntry dfs) {
   if (isa<EndBorrowInst>(use->getUser())) {
     return true;
   }
+
   // We weren't able to "see through" any more address conversions; so
   // record this as a use.
 
@@ -2657,6 +2664,7 @@ static void visitBuiltinAddress(BuiltinInst *builtin,
       
     // zeroInitializer with an address operand zeroes the address.
     case BuiltinValueKind::ZeroInitializer:
+    case BuiltinValueKind::PrepareInitialization:
       if (builtin->getAllOperands().size() > 0) {
         visitor(&builtin->getAllOperands()[0]);
       }
@@ -2734,7 +2742,6 @@ void swift::visitAccessedAddress(SILInstruction *I,
     llvm_unreachable("unexpected memory access.");
 
   case SILInstructionKind::AssignInst:
-  case SILInstructionKind::AssignByWrapperInst:
   case SILInstructionKind::AssignOrInitInst:
     visitor(&I->getAllOperands()[AssignInst::Dest]);
     return;
@@ -2793,6 +2800,23 @@ void swift::visitAccessedAddress(SILInstruction *I,
       visitor(singleOperand);
     return;
   }
+  case SILInstructionKind::EndBorrowInst: {
+    auto *ebi = cast<EndBorrowInst>(I);
+    SmallVector<SILValue, 4> roots;
+    findGuaranteedReferenceRoots(ebi->getOperand(),
+                                 /*lookThroughNestedBorrows=*/true, roots);
+    for (auto root : roots) {
+      if (auto *lbi = dyn_cast<LoadBorrowInst>(root)) {
+        visitor(&lbi->getOperandRef());
+        return;
+      }
+      if (auto *sbi = dyn_cast<StoreBorrowInst>(root)) {
+        visitor(&sbi->getOperandRef(StoreInst::Dest));
+        return;
+      }
+    }
+    break;
+  }
   // Non-access cases: these are marked with memory side effects, but, by
   // themselves, do not access formal memory.
 #define UNCHECKED_REF_STORAGE(Name, ...)                                       \
@@ -2809,6 +2833,7 @@ void swift::visitAccessedAddress(SILInstruction *I,
   case SILInstructionKind::BeginBorrowInst:
   case SILInstructionKind::BeginCOWMutationInst:
   case SILInstructionKind::EndCOWMutationInst:
+  case SILInstructionKind::EndCOWMutationAddrInst:
   case SILInstructionKind::BeginUnpairedAccessInst:
   case SILInstructionKind::BindMemoryInst:
   case SILInstructionKind::RebindMemoryInst:
@@ -2824,7 +2849,6 @@ void swift::visitAccessedAddress(SILInstruction *I,
   case SILInstructionKind::DropDeinitInst:
   case SILInstructionKind::EndAccessInst:
   case SILInstructionKind::EndApplyInst:
-  case SILInstructionKind::EndBorrowInst:
   case SILInstructionKind::EndUnpairedAccessInst:
   case SILInstructionKind::EndLifetimeInst:
   case SILInstructionKind::ExistentialMetatypeInst:
diff --git a/lib/SIL/Utils/OSSACompleteLifetime.cpp b/lib/SIL/Utils/OSSACompleteLifetime.cpp
new file mode 100644
index 0000000000000..63ecde193afd1
--- /dev/null
+++ b/lib/SIL/Utils/OSSACompleteLifetime.cpp
@@ -0,0 +1,713 @@
+//===--- OSSACompleteLifetime.cpp ---------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// OSSA lifetime completion adds lifetime ending instructions to make
+/// linear lifetimes complete.
+///
+/// Interior liveness handles the following cases naturally:
+///
+/// When completing the lifetime of the initial value, %v1, transitively
+/// include all uses of dominated reborrows as, such as %phi1 in this example:
+///
+///     %v1 = ...
+///     cond_br bb1, bb2
+///   bb1:
+///     %b1 = begin_borrow %v1
+///     br bb3(%b1)
+///   bb2:
+///     %b2 = begin_borrow %v1
+///     br bb3(%b2)
+///   bb3(%phi1):
+///     %u1 = %phi1
+///     end_borrow %phi1
+///     %k1 = destroy_value %v1 // must be below end_borrow %phi1
+///
+/// When completing the lifetime for a phi (%phi2) transitively include all
+/// uses of inner adjacent reborrows, such as %phi1 in this example:
+///
+///   bb1:
+///     %v1 = ...
+///     %b1 = begin_borrow %v1
+///     br bb3(%b1, %v1)
+///   bb2:
+///     %v2 = ...
+///     %b2 = begin_borrow %v2
+///     br bb3(%b2, %v2)
+///   bb3(%phi1, %phi2):
+///     %u1 = %phi1
+///     end_borrow %phi1
+///     %k1 = destroy_value %phi1
+///
+//===----------------------------------------------------------------------===//
+
+#include "swift/SIL/OSSACompleteLifetime.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/SIL/AddressWalker.h"
+#include "swift/SIL/BasicBlockUtils.h"
+#include "swift/SIL/SILBuilder.h"
+#include "swift/SIL/SILFunction.h"
+#include "swift/SIL/SILInstruction.h"
+#include "swift/SIL/Test.h"
+#include "llvm/ADT/STLExtras.h"
+
+using namespace swift;
+
+// FIXME: remove this option after fixing:
+// rdar://145994924 (Mem2Reg calls lifetime completion without checking for
+// pointer escapes)
+llvm::cl::opt<bool> VerifyLifetimeCompletion("verify-lifetime-completion",
+                                             llvm::cl::init(false),
+                                             llvm::cl::desc("."));
+
+static SILInstruction *endOSSALifetime(SILValue value,
+                                       OSSACompleteLifetime::LifetimeEnd end,
+                                       bool nonDestroyingEnd,
+                                       SILBuilder &builder,
+                                       DeadEndBlocks &deb) {
+  auto loc =
+      RegularLocation::getAutoGeneratedLocation(builder.getInsertionPointLoc());
+  if (end == OSSACompleteLifetime::LifetimeEnd::Loop) {
+    return builder.createExtendLifetime(loc, value);
+  }
+  auto isDeadEnd = IsDeadEnd_t(deb.isDeadEnd(builder.getInsertionBB()));
+  if (value->getOwnershipKind() == OwnershipKind::Owned) {
+    if (value->getType().is<SILBoxType>()) {
+      return builder.createDeallocBox(loc, value, isDeadEnd);
+    }
+    if (nonDestroyingEnd && !isDeadEnd) {
+      return builder.createEndLifetime(loc, value);
+    } else {
+      return builder.createDestroyValue(loc, value, DontPoisonRefs, isDeadEnd);
+    }
+  }
+  if (auto scopedAddress = ScopedAddressValue(value)) {
+    return scopedAddress.createScopeEnd(builder.getInsertionPoint(), loc);
+  }
+  if (value->getOwnershipKind() == OwnershipKind::None) {
+    return builder.createExtendLifetime(loc, value);
+  }
+  return builder.createEndBorrow(loc, lookThroughBorrowedFromUser(value));
+}
+
+static bool endLifetimeAtLivenessBoundary(SILValue value,
+                                          const SSAPrunedLiveness &liveness,
+                                          bool nonDestroyingEnd,
+                                          DeadEndBlocks &deb) {
+  PrunedLivenessBoundary boundary;
+  liveness.computeBoundary(boundary);
+
+  bool changed = false;
+  for (SILInstruction *lastUser : boundary.lastUsers) {
+    if (liveness.isInterestingUser(lastUser) !=
+        PrunedLiveness::LifetimeEndingUse) {
+      changed = true;
+      SILBuilderWithScope::insertAfter(
+          lastUser, [value, &deb, nonDestroyingEnd](SILBuilder &builder) {
+            endOSSALifetime(value, OSSACompleteLifetime::LifetimeEnd::Boundary,
+                            nonDestroyingEnd, builder, deb);
+          });
+    }
+  }
+  for (SILBasicBlock *edge : boundary.boundaryEdges) {
+    changed = true;
+    SILBuilderWithScope builder(edge->begin());
+    endOSSALifetime(value, OSSACompleteLifetime::LifetimeEnd::Boundary,\
+                    nonDestroyingEnd, builder, deb);
+  }
+  for (SILNode *deadDef : boundary.deadDefs) {
+    SILInstruction *next = nullptr;
+    if (auto *deadInst = dyn_cast<SILInstruction>(deadDef)) {
+      next = deadInst->getNextInstruction();
+    } else {
+      next = cast<ValueBase>(deadDef)->getNextInstruction();
+    }
+    changed = true;
+    SILBuilderWithScope builder(next);
+    endOSSALifetime(value, OSSACompleteLifetime::LifetimeEnd::Boundary,
+                    nonDestroyingEnd, builder, deb);
+  }
+  return changed;
+}
+
+static void visitUsersOutsideLinearLivenessBoundary(
+    SILValue value, const SSAPrunedLiveness &liveness,
+    llvm::function_ref<void(SILInstruction *)> visitor) {
+  if (value->getOwnershipKind() == OwnershipKind::None) {
+    return;
+  }
+  LinearLiveness linearLiveness(value);
+  linearLiveness.compute();
+  for (auto pair : liveness.getAllUsers()) {
+    if (pair.second.isEnding() || isa<ExtendLifetimeInst>(pair.first)) {
+      continue;
+    }
+    auto *user = pair.first;
+    if (linearLiveness.getLiveness().isWithinBoundary(
+            user, /*deadEndBlocks=*/nullptr)) {
+      continue;
+    }
+    visitor(user);
+  }
+}
+
+namespace swift::test {
+// Arguments:
+// - SILValue: value
+// Dumps:
+// - the instructions outside the liveness boundary
+static FunctionTest LivenessPartialBoundaryOutsideUsersTest(
+    "liveness_partial_boundary_outside_users",
+    [](auto &function, auto &arguments, auto &test) {
+      SILValue value = arguments.takeValue();
+      InteriorLiveness liveness(value);
+      liveness.compute(test.getDominanceInfo());
+      visitUsersOutsideLinearLivenessBoundary(
+          value, liveness.getLiveness(),
+          [](auto *inst) { inst->print(llvm::outs()); });
+    });
+} // end namespace swift::test
+
+namespace {
+/// Visits the latest instructions at which `value` is available.
+///
+/// Together with visitUsersOutsideLinearLivenessBoundary, implements
+/// OSSACompleteLifetime::visitAvailabilityBoundary.
+///
+/// Finding these positions is a three step process:
+/// 1) computeRegion: Forward CFG walk from non-lifetime-ending boundary to find
+///                   the dead-end region in which the value might be available.
+/// 2) propagateAvailability: Forward iterative dataflow within the region to
+///                           determine which blocks the value is available in.
+/// 3) visitAvailabilityBoundary: Visits the final blocks in the region where
+///                               the value is available--these are the blocks
+///                               without successors or with at least one
+///                               unavailable successor.
+class AvailabilityBoundaryVisitor {
+  /// The value whose dead-end block lifetime ends are to be visited.
+  SILValue value;
+
+  /// The non-lifetime-ending boundary of `value`.
+  BasicBlockSet starts;
+  /// The region between (inclusive) the `starts` and the unreachable blocks.
+  BasicBlockSetVector region;
+
+public:
+  AvailabilityBoundaryVisitor(SILValue value)
+      : value(value), starts(value->getFunction()),
+        region(value->getFunction()) {}
+
+  using Visit = llvm::function_ref<void(SILInstruction *,
+                                        OSSACompleteLifetime::LifetimeEnd)>;
+
+  struct Result;
+
+  /// Do all three steps at once.
+  void visit(const SSAPrunedLiveness &liveness, Result &result, Visit visit);
+
+private:
+  /// Region discovery.
+  ///
+  /// Forward CFG walk from non-lifetime-ending boundary to unreachable
+  /// instructions.
+  void computeRegion(const SSAPrunedLiveness &liveness);
+
+  /// Iterative dataflow to determine availability for each block in `region`.
+  void propagateAvailablity(Result &result);
+
+  /// Visit the terminators of blocks on the boundary of availability.
+  void visitAvailabilityBoundary(Result const &result, Visit visit);
+
+  struct State {
+    enum Value : uint8_t {
+      Unavailable = 0,
+      Available,
+      Unknown,
+    };
+    Value value;
+
+    State(Value value) : value(value){};
+    operator Value() const { return value; }
+    State meet(State const other) const {
+      return *this < other ? *this : other;
+    }
+  };
+
+public:
+  struct Result {
+    BasicBlockBitfield states;
+
+    Result(SILFunction *function) : states(function, 2) {}
+
+    State getState(SILBasicBlock *block) const {
+      return {(State::Value)states.get(block)};
+    }
+
+    void setState(SILBasicBlock *block, State newState) {
+      states.set(block, (unsigned)newState.value);
+    }
+
+    /// Propagate predecessors' state into `block`.
+    ///
+    /// states[block] ∧= state[predecessor_1] ∧ ... ∧ state[predecessor_n]
+    bool updateState(SILBasicBlock *block) {
+      auto oldState = getState(block);
+      auto state = oldState;
+      for (auto *predecessor : block->getPredecessorBlocks()) {
+        state = state.meet(getState(predecessor));
+      }
+      setState(block, state);
+      return state != oldState;
+    }
+  };
+};
+
+void AvailabilityBoundaryVisitor::visit(const SSAPrunedLiveness &liveness,
+                                        Result &result, Visit visit) {
+  computeRegion(liveness);
+
+  propagateAvailablity(result);
+
+  visitAvailabilityBoundary(result, visit);
+}
+
+void AvailabilityBoundaryVisitor::computeRegion(
+    const SSAPrunedLiveness &liveness) {
+  // (1) Compute the complete liveness boundary.
+  PrunedLivenessBlockBoundary boundary;
+  liveness.computeBoundary(boundary);
+
+  BasicBlockSet consumingBlocks(value->getFunction());
+
+  liveness.visitUsers(
+      [&consumingBlocks](auto *instruction, auto lifetimeEnding) {
+        if (lifetimeEnding.isEnding()) {
+          consumingBlocks.insert(instruction->getParent());
+        }
+      });
+
+  // Used in the forward walk below (3).
+  BasicBlockWorklist regionWorklist(value->getFunction());
+
+  // (2) Collect the non-lifetime-ending liveness boundary.  This is the
+  //     portion of `boundary` consisting of:
+  // - non-lifetime-ending instructions (their parent blocks)
+  // - boundary edges
+  // - dead defs (their parent blocks)
+  auto collect = [&](SILBasicBlock *block) {
+    // `region` consists of the non-lifetime-ending boundary and all its
+    // iterative successors.
+    region.insert(block);
+    // `starts` just consists of the blocks in the non-lifetime-ending
+    // boundary.
+    starts.insert(block);
+    // The forward walk begins from the non-lifetime-ending boundary.
+    regionWorklist.push(block);
+  };
+
+  // Trivial values that correspond to local variables (as opposed to
+  // ScopedAddresses) are available only up to their last extend_lifetime on
+  // non-dead-end paths. They cannot be consumed, but are only "available" up to
+  // the end of their scope.
+  if (value->getOwnershipKind() != OwnershipKind::None ||
+      ScopedAddressValue(value)) {
+    for (auto *endBlock : boundary.endBlocks) {
+      if (!consumingBlocks.contains(endBlock)) {
+        collect(endBlock);
+      }
+    }
+  }
+  for (SILBasicBlock *edge : boundary.boundaryEdges) {
+    collect(edge);
+  }
+
+  // (3) Forward walk to find the region in which `value` might be available.
+  while (auto *block = regionWorklist.pop()) {
+    if (block->succ_empty()) {
+      // This is a function-exiting block.
+      //
+      // In valid-but-lifetime-incomplete OSSA there must be a lifetime-ending
+      // instruction on each path from the def that exits the function normally.
+      // Thus finding a value available at the end of such a block means that
+      // the block does _not_ must not exits the function normally; in other
+      // words its terminator must be an UnreachableInst.
+      if (!isa<UnreachableInst>(block->getTerminator()) &&
+          block->getFunction()
+              ->getModule()
+              .getASTContext()
+              .SILOpts.VerifySILOwnership) {
+        llvm::errs() << "Invalid SIL provided to OSSACompleteLifetime?! {{\n";
+        llvm::errs() << "OSSACompleteLifetime is visiting the availability "
+                        "boundary of ";
+        value->print(llvm::errs());
+        llvm::errs()
+            << "When walking forward from the def to the availability boundary "
+               "a non-dead-end successor-less block was encountered: bb"
+            << block->getDebugID()
+            << "\nIts terminator must be an unreachable but is actually "
+               "instead "
+            << *block->getTerminator()
+            << "The walk stops at consumes, so reaching such a block means the "
+               "value was leaked.  The function with the leak is as follows:\n";
+        block->getFunction()->print(llvm::errs());
+        llvm::errs()
+            << "Invalid SIL provided to OSSACompleteLifetime?! }}\n"
+            << "Something that ran before OSSACompleteLifetime (the current "
+               "pass, an earlier pass, SILGen) has introduced a leak of this "
+               "value.\n"
+            << "Please rerun the crashing swift-frontend command with the "
+               "following flags added and file a bug with the output:\n"
+            << "-sil-ownership-verify-all -Xllvm '-sil-print-function="
+            << block->getFunction()->getName()
+            << "' -Xllvm -sil-print-types -Xllvm -sil-print-module-on-error\n";
+        llvm::errs() << "Use the -disable-sil-ownership-verifier frontend flag "
+                        "to disable this check.\n";
+        llvm::report_fatal_error("Invalid lifetime of value whose availability "
+                                 "boundary is being visited.");
+      }
+    }
+    for (auto *successor : block->getSuccessorBlocks()) {
+      regionWorklist.pushIfNotVisited(successor);
+      region.insert(successor);
+    }
+  }
+}
+
+void AvailabilityBoundaryVisitor::propagateAvailablity(Result &result) {
+  // Initialize per-block state.
+  // - all blocks outside of the region are ::Unavailable (automatically
+  //   initialized)
+  // - non-initial in-region blocks are Unknown
+  // - start blocks are ::Available
+  for (auto *block : region) {
+    if (starts.contains(block))
+      result.setState(block, State::Available);
+    else
+      result.setState(block, State::Unknown);
+  }
+
+  BasicBlockWorklist worklist(value->getFunction());
+
+  // Initialize worklist with all participating blocks.
+  //
+  // Only perform dataflow in the non-initial region.  Every initial block is
+  // by definition ::Available.
+  for (auto *block : region) {
+    if (starts.contains(block))
+      continue;
+    worklist.push(block);
+  }
+
+  // Iterate over blocks which are successors of blocks whose state changed.
+  while (auto *block = worklist.popAndForget()) {
+    // Only propagate availability in non-initial, in-region blocks.
+    if (!region.contains(block) || starts.contains(block))
+      continue;
+    auto changed = result.updateState(block);
+    if (!changed) {
+      continue;
+    }
+    // The state has changed.  Propagate the new state into successors.
+    for (auto *successor : block->getSuccessorBlocks()) {
+      worklist.pushIfNotVisited(successor);
+    }
+  }
+}
+
+void AvailabilityBoundaryVisitor::visitAvailabilityBoundary(
+    Result const &result,
+    llvm::function_ref<void(SILInstruction *,
+                            OSSACompleteLifetime::LifetimeEnd end)>
+        visit) {
+  for (auto *block : region) {
+    auto available = result.getState(block) == State::Available;
+    if (!available) {
+      continue;
+    }
+    auto hasUnavailableSuccessor = [&]() {
+      // Use a lambda to avoid checking if possible.
+      return llvm::any_of(block->getSuccessorBlocks(), [&result](auto *block) {
+        return result.getState(block) == State::Unavailable;
+      });
+    };
+    if (!block->succ_empty() && !hasUnavailableSuccessor()) {
+      continue;
+    }
+    assert(hasUnavailableSuccessor() ||
+           isa<UnreachableInst>(block->getTerminator()) ||
+           !block->getFunction()
+                ->getModule()
+                .getASTContext()
+                .SILOpts.VerifySILOwnership);
+    visit(block->getTerminator(), OSSACompleteLifetime::LifetimeEnd::Boundary);
+  }
+}
+} // end anonymous namespace
+
+void OSSACompleteLifetime::visitAvailabilityBoundary(
+    SILValue value, const SSAPrunedLiveness &liveness,
+    llvm::function_ref<void(SILInstruction *, LifetimeEnd end)> visit) {
+
+  AvailabilityBoundaryVisitor visitor(value);
+  AvailabilityBoundaryVisitor::Result result(value->getFunction());
+  visitor.visit(liveness, result, visit);
+
+  visitUsersOutsideLinearLivenessBoundary(
+      value, liveness, [&](auto *instruction) {
+        instruction->visitSubsequentInstructions([&](auto *next) {
+          visit(next, LifetimeEnd::Loop);
+          return true;
+        });
+      });
+}
+
+static bool endLifetimeAtAvailabilityBoundary(SILValue value,
+                                              const SSAPrunedLiveness &liveness,
+                                              bool nonDestroyingEnd,
+                                              DeadEndBlocks &deb) {
+  bool changed = false;
+  OSSACompleteLifetime::visitAvailabilityBoundary(
+      value, liveness, [&](auto *unreachable, auto end) {
+        SILBuilderWithScope builder(unreachable);
+        endOSSALifetime(value, end, nonDestroyingEnd, builder, deb);
+        changed = true;
+      });
+  return changed;
+}
+
+static bool endLifetimeAtBoundary(SILValue value,
+                                  SSAPrunedLiveness const &liveness,
+                                  OSSACompleteLifetime::Boundary boundary,
+                                  bool nonDestroyingEnd,
+                                  DeadEndBlocks &deadEndBlocks) {
+  bool changed = false;
+  switch (boundary) {
+  case OSSACompleteLifetime::Boundary::Liveness:
+    changed |= endLifetimeAtLivenessBoundary(value, liveness, nonDestroyingEnd, deadEndBlocks);
+    break;
+  case OSSACompleteLifetime::Boundary::Availability:
+    changed |=
+        endLifetimeAtAvailabilityBoundary(value, liveness, nonDestroyingEnd, deadEndBlocks);
+    break;
+  }
+  return changed;
+}
+
+bool OSSACompleteLifetime::analyzeAndUpdateLifetime(
+    ScopedAddressValue scopedAddress, Boundary boundary) {
+  SmallVector<SILBasicBlock *, 8> discoveredBlocks;
+  SSAPrunedLiveness liveness(scopedAddress->getFunction(), &discoveredBlocks);
+  liveness.initializeDef(scopedAddress.value);
+
+  struct Walker : TransitiveAddressWalker<Walker> {
+    OSSACompleteLifetime &completion;
+    ScopedAddressValue scopedAddress;
+    Boundary boundary;
+    SSAPrunedLiveness &liveness;
+    Walker(OSSACompleteLifetime &completion, ScopedAddressValue scopedAddress,
+           Boundary boundary, SSAPrunedLiveness &liveness)
+        : completion(completion), scopedAddress(scopedAddress),
+          boundary(boundary), liveness(liveness) {}
+    bool visitUse(Operand *use) {
+      auto *user = use->getUser();
+      if (scopedAddress.isScopeEndingUse(use)) {
+        liveness.updateForUse(user, /*lifetimeEnding=*/true);
+        return true;
+      }
+      liveness.updateForUse(user, /*lifetimeEnding=*/false);
+      for (auto result : user->getResults()) {
+        auto shouldComplete =
+            (bool)BorrowedValue(result) || (bool)ScopedAddressValue(result);
+        if (!shouldComplete)
+          continue;
+        auto completed = completion.completeOSSALifetime(result, boundary);
+        switch (completed) {
+        case LifetimeCompletion::NoLifetime:
+          break;
+        case LifetimeCompletion::AlreadyComplete:
+        case LifetimeCompletion::WasCompleted:
+          for (auto *consume : result->getConsumingUses()) {
+            liveness.updateForUse(consume->getUser(), /*lifetimeEnding=*/false);
+          }
+          break;
+        }
+      }
+      return true;
+    }
+  };
+  Walker walker(*this, scopedAddress, boundary, liveness);
+  AddressUseKind result = walker.walk(scopedAddress.value);
+  if ((VerifyLifetimeCompletion || ForceLivenessVerification) &&
+      boundary != Boundary::Availability &&
+      result != AddressUseKind::NonEscaping) {
+    llvm::errs() << "Incomplete liveness for:\n" << scopedAddress.value;
+    if (auto *escapingUse = walker.getEscapingUse()) {
+      llvm::errs() << "  escapes at:\n";
+      escapingUse->getUser()->printInContext(llvm::errs());
+    }
+    ASSERT(false && "caller must check for pointer escapes");
+  }
+  return endLifetimeAtBoundary(scopedAddress.value, liveness, boundary,
+                               nonDestroyingEnd, deadEndBlocks);
+}
+
+/// End the lifetime of \p value at unreachable instructions.
+///
+/// Returns true if any new instructions were created to complete the lifetime.
+bool OSSACompleteLifetime::analyzeAndUpdateLifetime(SILValue value,
+                                                    Boundary boundary) {
+  if (auto scopedAddress = ScopedAddressValue(value)) {
+    return analyzeAndUpdateLifetime(scopedAddress, boundary);
+  }
+  // Called for inner borrows, inner adjacent reborrows, inner reborrows, and
+  // scoped addresses.
+  auto handleInnerScope = [this, boundary](SILValue innerBorrowedValue) {
+    completeOSSALifetime(innerBorrowedValue, boundary);
+  };
+  if (value->getOwnershipKind() == OwnershipKind::None) {
+    // Trivial variable lifetimes are only relevant up to the extend_lifetime
+    // instructions emitted by SILGen. Their other uses have no meaning with
+    // respect to lifetime. The only purpose of "completing" their lifetime is
+    // to insert extend_lifetime on dead-end blocks.
+    LinearLiveness liveness(value);
+    liveness.compute();
+    return endLifetimeAtBoundary(value, liveness.getLiveness(), boundary,
+                                 nonDestroyingEnd, deadEndBlocks);
+  }
+  InteriorLiveness liveness(value);
+  liveness.compute(domInfo, handleInnerScope);
+  if (VerifyLifetimeCompletion && boundary != Boundary::Availability &&
+      liveness.getAddressUseKind() != AddressUseKind::NonEscaping) {
+    llvm::errs() << "Incomplete liveness for: " << value;
+    if (auto *escapingUse = liveness.escapingUse) {
+      llvm::errs() << "  escapes at:\n";
+      escapingUse->getUser()->printInContext(llvm::errs());
+    }
+    ASSERT(false && "caller must check for pointer escapes");
+  }
+  return endLifetimeAtBoundary(value, liveness.getLiveness(), boundary,
+                               nonDestroyingEnd, deadEndBlocks);
+}
+
+namespace swift::test {
+// Arguments:
+// - SILValue: value
+// - string: either "liveness" or "availability"
+// Dumps:
+// - function
+static FunctionTest OSSACompleteLifetimeTest(
+    "ossa_complete_lifetime", [](auto &function, auto &arguments, auto &test) {
+      SILValue value = arguments.takeValue();
+      OSSACompleteLifetime::Boundary kind = OSSACompleteLifetime::Boundary::Liveness;
+      bool nonDestroyingEnd = false;
+      StringRef kindArg = arguments.takeString();
+      if (kindArg == "liveness_no_destroy") {
+        nonDestroyingEnd = true;
+      } else if (kindArg == "availability") {
+        kind = OSSACompleteLifetime::Boundary::Availability;
+      } else {
+        assert(kindArg == "liveness");
+      }
+      auto *deb = test.getDeadEndBlocks();
+      llvm::outs() << "OSSA lifetime completion on " << kind
+                   << " boundary: " << value;
+      OSSACompleteLifetime completion(&function, /*domInfo*/ nullptr, *deb,
+                                      OSSACompleteLifetime::IgnoreTrivialVariable,
+                                      /*forceLivenessVerification=*/false,
+                                      nonDestroyingEnd);
+      completion.completeOSSALifetime(value, kind);
+      function.print(llvm::outs());
+    });
+} // end namespace swift::test
+
+// TODO: create a fast check for 'mayEndLifetime(SILInstruction *)'. Verify that
+// it returns true for every instruction that has a lifetime-ending operand.
+void UnreachableLifetimeCompletion::visitUnreachableInst(
+    SILInstruction *instruction) {
+  auto *block = instruction->getParent();
+  bool inReachableBlock = !unreachableBlocks.contains(block);
+  // If this instruction's block is already marked unreachable, and
+  // updatingLifetimes is not yet set, then this instruction will be visited
+  // again later when propagating unreachable blocks.
+  if (!inReachableBlock && !updatingLifetimes)
+    return;
+
+  for (Operand &operand : instruction->getAllOperands()) {
+    if (!operand.isLifetimeEnding())
+      continue;
+
+    SILValue value = operand.get();
+    SILBasicBlock *defBlock = value->getParentBlock();
+    if (unreachableBlocks.contains(defBlock))
+      continue;
+
+    auto *def = value->getDefiningInstruction();
+    if (def && unreachableInsts.contains(def))
+      continue;
+
+    // The operand's definition is still reachable and its lifetime ends on a
+    // newly unreachable path.
+    //
+    // Note: The arguments of a no-return try_apply may still appear reachable
+    // here because the try_apply itself is never visited as unreachable, hence
+    // its successor blocks are not marked . But it
+    // seems harmless to recompute their lifetimes.
+
+    // Insert this unreachable instruction in unreachableInsts if its parent
+    // block is not already marked unreachable.
+    if (inReachableBlock) {
+      unreachableInsts.insert(instruction);
+    }
+    incompleteValues.insert(value);
+
+    // Add unreachable successors to the forward traversal worklist.
+    if (auto *term = dyn_cast<TermInst>(instruction)) {
+      for (auto *succBlock : term->getSuccessorBlocks()) {
+        if (llvm::all_of(succBlock->getPredecessorBlocks(),
+                         [&](SILBasicBlock *predBlock) {
+                           if (predBlock == block)
+                             return true;
+
+                           return unreachableBlocks.contains(predBlock);
+                         })) {
+          unreachableBlocks.insert(succBlock);
+        }
+      }
+    }
+  }
+}
+
+bool UnreachableLifetimeCompletion::completeLifetimes() {
+  assert(!updatingLifetimes && "don't call this more than once");
+  updatingLifetimes = true;
+
+  // Now that all unreachable terminator instructions have been visited,
+  // propagate unreachable blocks.
+  for (auto blockIt = unreachableBlocks.begin();
+       blockIt != unreachableBlocks.end(); ++blockIt) {
+    auto *block = *blockIt;
+    for (auto &instruction : *block) {
+      visitUnreachableInst(&instruction);
+    }
+  }
+
+  OSSACompleteLifetime completion(function, domInfo, deadEndBlocks);
+
+  bool changed = false;
+  for (auto value : incompleteValues) {
+    if (completion.completeOSSALifetime(
+            value, OSSACompleteLifetime::Boundary::Availability) ==
+        LifetimeCompletion::WasCompleted) {
+      changed = true;
+    }
+  }
+  return changed;
+}
diff --git a/lib/SIL/Utils/OSSALifetimeCompletion.cpp b/lib/SIL/Utils/OSSALifetimeCompletion.cpp
deleted file mode 100644
index 358eb4388bd3e..0000000000000
--- a/lib/SIL/Utils/OSSALifetimeCompletion.cpp
+++ /dev/null
@@ -1,662 +0,0 @@
-//===--- OSSALifetimeCompletion.cpp ---------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// OSSA lifetime completion adds lifetime ending instructions to make
-/// linear lifetimes complete.
-///
-/// Interior liveness handles the following cases naturally:
-///
-/// When completing the lifetime of the initial value, %v1, transitively
-/// include all uses of dominated reborrows as, such as %phi1 in this example:
-///
-///     %v1 = ...
-///     cond_br bb1, bb2
-///   bb1:
-///     %b1 = begin_borrow %v1
-///     br bb3(%b1)
-///   bb2:
-///     %b2 = begin_borrow %v1
-///     br bb3(%b2)
-///   bb3(%phi1):
-///     %u1 = %phi1
-///     end_borrow %phi1
-///     %k1 = destroy_value %v1 // must be below end_borrow %phi1
-///
-/// When completing the lifetime for a phi (%phi2) transitively include all
-/// uses of inner adjacent reborrows, such as %phi1 in this example:
-///
-///   bb1:
-///     %v1 = ...
-///     %b1 = begin_borrow %v1
-///     br bb3(%b1, %v1)
-///   bb2:
-///     %v2 = ...
-///     %b2 = begin_borrow %v2
-///     br bb3(%b2, %v2)
-///   bb3(%phi1, %phi2):
-///     %u1 = %phi1
-///     end_borrow %phi1
-///     %k1 = destroy_value %phi1
-///
-//===----------------------------------------------------------------------===//
-
-#include "swift/SIL/OSSALifetimeCompletion.h"
-#include "swift/Basic/Assertions.h"
-#include "swift/SIL/AddressWalker.h"
-#include "swift/SIL/BasicBlockUtils.h"
-#include "swift/SIL/SILBuilder.h"
-#include "swift/SIL/SILFunction.h"
-#include "swift/SIL/SILInstruction.h"
-#include "swift/SIL/Test.h"
-#include "llvm/ADT/STLExtras.h"
-
-using namespace swift;
-
-// FIXME: remove this option after fixing:
-// rdar://145994924 (Mem2Reg calls lifetime completion without checking for
-// pointer escapes)
-llvm::cl::opt<bool> VerifyLifetimeCompletion(
-    "verify-lifetime-completion", llvm::cl::init(false),
-    llvm::cl::desc("."));
-
-static SILInstruction *endOSSALifetime(SILValue value,
-                                       OSSALifetimeCompletion::LifetimeEnd end,
-                                       SILBuilder &builder,
-                                       DeadEndBlocks &deb) {
-  auto loc =
-    RegularLocation::getAutoGeneratedLocation(builder.getInsertionPointLoc());
-  if (end == OSSALifetimeCompletion::LifetimeEnd::Loop) {
-    return builder.createExtendLifetime(loc, value);
-  }
-  auto isDeadEnd = IsDeadEnd_t(deb.isDeadEnd(builder.getInsertionBB()));
-  if (value->getOwnershipKind() == OwnershipKind::Owned) {
-    if (value->getType().is<SILBoxType>()) {
-      return builder.createDeallocBox(loc, value, isDeadEnd);
-    }
-    return builder.createDestroyValue(loc, value, DontPoisonRefs, isDeadEnd);
-  }
-  if (auto scopedAddress = ScopedAddressValue(value)) {
-    return scopedAddress.createScopeEnd(builder.getInsertionPoint(), loc);
-  }
-  if (value->getOwnershipKind() == OwnershipKind::None) {
-    return builder.createExtendLifetime(loc, value);
-  }
-  return builder.createEndBorrow(loc, lookThroughBorrowedFromUser(value));
-}
-
-static bool endLifetimeAtLivenessBoundary(SILValue value,
-                                          const SSAPrunedLiveness &liveness,
-                                          DeadEndBlocks &deb) {
-  PrunedLivenessBoundary boundary;
-  liveness.computeBoundary(boundary);
-
-  bool changed = false;
-  for (SILInstruction *lastUser : boundary.lastUsers) {
-    if (liveness.isInterestingUser(lastUser)
-        != PrunedLiveness::LifetimeEndingUse) {
-      changed = true;
-      SILBuilderWithScope::insertAfter(lastUser, [value,
-                                                  &deb](SILBuilder &builder) {
-        endOSSALifetime(value, OSSALifetimeCompletion::LifetimeEnd::Boundary,
-                        builder, deb);
-      });
-    }
-  }
-  for (SILBasicBlock *edge : boundary.boundaryEdges) {
-    changed = true;
-    SILBuilderWithScope builder(edge->begin());
-    endOSSALifetime(value, OSSALifetimeCompletion::LifetimeEnd::Boundary,
-                    builder, deb);
-  }
-  for (SILNode *deadDef : boundary.deadDefs) {
-    SILInstruction *next = nullptr;
-    if (auto *deadInst = dyn_cast<SILInstruction>(deadDef)) {
-      next = deadInst->getNextInstruction();
-    } else {
-      next = cast<ValueBase>(deadDef)->getNextInstruction();
-    }
-    changed = true;
-    SILBuilderWithScope builder(next);
-    endOSSALifetime(value, OSSALifetimeCompletion::LifetimeEnd::Boundary,
-                    builder, deb);
-  }
-  return changed;
-}
-
-static void visitUsersOutsideLinearLivenessBoundary(
-    SILValue value, const SSAPrunedLiveness &liveness,
-    llvm::function_ref<void(SILInstruction *)> visitor) {
-  if (value->getOwnershipKind() == OwnershipKind::None) {
-    return;
-  }
-  LinearLiveness linearLiveness(value);
-  linearLiveness.compute();
-  for (auto pair : liveness.getAllUsers()) {
-    if (pair.second.isEnding() || isa<ExtendLifetimeInst>(pair.first)) {
-      continue;
-    }
-    auto *user = pair.first;
-    if (linearLiveness.getLiveness().isWithinBoundary(
-            user, /*deadEndBlocks=*/nullptr)) {
-      continue;
-    }
-    visitor(user);
-  }
-}
-
-namespace swift::test {
-// Arguments:
-// - SILValue: value
-// Dumps:
-// - the instructions outside the liveness boundary
-static FunctionTest LivenessPartialBoundaryOutsideUsersTest(
-    "liveness_partial_boundary_outside_users",
-    [](auto &function, auto &arguments, auto &test) {
-      SILValue value = arguments.takeValue();
-      InteriorLiveness liveness(value);
-      liveness.compute(test.getDominanceInfo());
-      visitUsersOutsideLinearLivenessBoundary(
-          value, liveness.getLiveness(),
-          [](auto *inst) { inst->print(llvm::outs()); });
-    });
-} // end namespace swift::test
-
-namespace {
-/// Visits the latest instructions at which `value` is available.
-///
-/// Together with visitUsersOutsideLinearLivenessBoundary, implements
-/// OSSALifetimeCompletion::visitAvailabilityBoundary.
-///
-/// Finding these positions is a three step process:
-/// 1) computeRegion: Forward CFG walk from non-lifetime-ending boundary to find
-///                   the dead-end region in which the value might be available.
-/// 2) propagateAvailability: Forward iterative dataflow within the region to
-///                           determine which blocks the value is available in.
-/// 3) visitAvailabilityBoundary: Visits the final blocks in the region where
-///                               the value is available--these are the blocks
-///                               without successors or with at least one
-///                               unavailable successor.
-class AvailabilityBoundaryVisitor {
-  /// The value whose dead-end block lifetime ends are to be visited.
-  SILValue value;
-
-  /// The non-lifetime-ending boundary of `value`.
-  BasicBlockSet starts;
-  /// The region between (inclusive) the `starts` and the unreachable blocks.
-  BasicBlockSetVector region;
-
-public:
-  AvailabilityBoundaryVisitor(SILValue value)
-      : value(value), starts(value->getFunction()),
-        region(value->getFunction()) {}
-
-  using Visit = llvm::function_ref<void(SILInstruction *,
-                                        OSSALifetimeCompletion::LifetimeEnd)>;
-
-  struct Result;
-
-  /// Do all three steps at once.
-  void visit(const SSAPrunedLiveness &liveness, Result &result, Visit visit);
-
-private:
-  /// Region discovery.
-  ///
-  /// Forward CFG walk from non-lifetime-ending boundary to unreachable
-  /// instructions.
-  void computeRegion(const SSAPrunedLiveness &liveness);
-
-  /// Iterative dataflow to determine availability for each block in `region`.
-  void propagateAvailablity(Result &result);
-
-  /// Visit the terminators of blocks on the boundary of availability.
-  void visitAvailabilityBoundary(Result const &result, Visit visit);
-
-  struct State {
-    enum Value : uint8_t {
-      Unavailable = 0,
-      Available,
-      Unknown,
-    };
-    Value value;
-
-    State(Value value) : value(value){};
-    operator Value() const { return value; }
-    State meet(State const other) const {
-      return *this < other ? *this : other;
-    }
-  };
-
-public:
-  struct Result {
-    BasicBlockBitfield states;
-
-    Result(SILFunction *function) : states(function, 2) {}
-
-    State getState(SILBasicBlock *block) const {
-      return {(State::Value)states.get(block)};
-    }
-
-    void setState(SILBasicBlock *block, State newState) {
-      states.set(block, (unsigned)newState.value);
-    }
-
-    /// Propagate predecessors' state into `block`.
-    ///
-    /// states[block] ∧= state[predecessor_1] ∧ ... ∧ state[predecessor_n]
-    bool updateState(SILBasicBlock *block) {
-      auto oldState = getState(block);
-      auto state = oldState;
-      for (auto *predecessor : block->getPredecessorBlocks()) {
-        state = state.meet(getState(predecessor));
-      }
-      setState(block, state);
-      return state != oldState;
-    }
-  };
-};
-
-void AvailabilityBoundaryVisitor::visit(const SSAPrunedLiveness &liveness,
-                                        Result &result, Visit visit) {
-  computeRegion(liveness);
-
-  propagateAvailablity(result);
-
-  visitAvailabilityBoundary(result, visit);
-}
-
-void AvailabilityBoundaryVisitor::computeRegion(
-    const SSAPrunedLiveness &liveness) {
-  // (1) Compute the complete liveness boundary.
-  PrunedLivenessBlockBoundary boundary;
-  liveness.computeBoundary(boundary);
-
-  BasicBlockSet consumingBlocks(value->getFunction());
-
-  liveness.visitUsers(
-      [&consumingBlocks](auto *instruction, auto lifetimeEnding) {
-        if (lifetimeEnding.isEnding()) {
-          consumingBlocks.insert(instruction->getParent());
-        }
-      });
-
-  // Used in the forward walk below (3).
-  BasicBlockWorklist regionWorklist(value->getFunction());
-
-  // (2) Collect the non-lifetime-ending liveness boundary.  This is the
-  //     portion of `boundary` consisting of:
-  // - non-lifetime-ending instructions (their parent blocks)
-  // - boundary edges
-  // - dead defs (their parent blocks)
-  auto collect = [&](SILBasicBlock *block) {
-    // `region` consists of the non-lifetime-ending boundary and all its
-    // iterative successors.
-    region.insert(block);
-    // `starts` just consists of the blocks in the non-lifetime-ending
-    // boundary.
-    starts.insert(block);
-    // The forward walk begins from the non-lifetime-ending boundary.
-    regionWorklist.push(block);
-  };
-
-  // Trivial values that correspond to local variables (as opposed to
-  // ScopedAddresses) are available only up to their last extend_lifetime on
-  // non-dead-end paths. They cannot be consumed, but are only "available" up to
-  // the end of their scope.
-  if (value->getOwnershipKind() != OwnershipKind::None
-      || ScopedAddressValue(value)) {
-    for (auto *endBlock : boundary.endBlocks) {
-      if (!consumingBlocks.contains(endBlock)) {
-        collect(endBlock);
-      }
-    }
-  }
-  for (SILBasicBlock *edge : boundary.boundaryEdges) {
-    collect(edge);
-  }
-
-  // (3) Forward walk to find the region in which `value` might be available.
-  while (auto *block = regionWorklist.pop()) {
-    if (block->succ_empty()) {
-      // This is a function-exiting block.
-      //
-      // In valid-but-lifetime-incomplete OSSA there must be a lifetime-ending
-      // instruction on each path from the def that exits the function normally.
-      // Thus finding a value available at the end of such a block means that
-      // the block does _not_ must not exits the function normally; in other
-      // words its terminator must be an UnreachableInst.
-      assert(isa<UnreachableInst>(block->getTerminator()));
-    }
-    for (auto *successor : block->getSuccessorBlocks()) {
-      regionWorklist.pushIfNotVisited(successor);
-      region.insert(successor);
-    }
-  }
-}
-
-void AvailabilityBoundaryVisitor::propagateAvailablity(Result &result) {
-  // Initialize per-block state.
-  // - all blocks outside of the region are ::Unavailable (automatically
-  //   initialized)
-  // - non-initial in-region blocks are Unknown
-  // - start blocks are ::Available
-  for (auto *block : region) {
-    if (starts.contains(block))
-      result.setState(block, State::Available);
-    else
-      result.setState(block, State::Unknown);
-  }
-
-  BasicBlockWorklist worklist(value->getFunction());
-
-  // Initialize worklist with all participating blocks.
-  //
-  // Only perform dataflow in the non-initial region.  Every initial block is
-  // by definition ::Available.
-  for (auto *block : region) {
-    if (starts.contains(block))
-      continue;
-    worklist.push(block);
-  }
-
-  // Iterate over blocks which are successors of blocks whose state changed.
-  while (auto *block = worklist.popAndForget()) {
-    // Only propagate availability in non-initial, in-region blocks.
-    if (!region.contains(block) || starts.contains(block))
-      continue;
-    auto changed = result.updateState(block);
-    if (!changed) {
-      continue;
-    }
-    // The state has changed.  Propagate the new state into successors.
-    for (auto *successor : block->getSuccessorBlocks()) {
-      worklist.pushIfNotVisited(successor);
-    }
-  }
-}
-
-void AvailabilityBoundaryVisitor::visitAvailabilityBoundary(
-    Result const &result,
-    llvm::function_ref<void(SILInstruction *,
-                            OSSALifetimeCompletion::LifetimeEnd end)>
-        visit) {
-  for (auto *block : region) {
-    auto available = result.getState(block) == State::Available;
-    if (!available) {
-      continue;
-    }
-    auto hasUnavailableSuccessor = [&]() {
-      // Use a lambda to avoid checking if possible.
-      return llvm::any_of(block->getSuccessorBlocks(), [&result](auto *block) {
-        return result.getState(block) == State::Unavailable;
-      });
-    };
-    if (!block->succ_empty() && !hasUnavailableSuccessor()) {
-      continue;
-    }
-    assert(hasUnavailableSuccessor() ||
-           isa<UnreachableInst>(block->getTerminator()));
-    visit(block->getTerminator(),
-          OSSALifetimeCompletion::LifetimeEnd::Boundary);
-  }
-}
-} // end anonymous namespace
-
-void OSSALifetimeCompletion::visitAvailabilityBoundary(
-    SILValue value, const SSAPrunedLiveness &liveness,
-    llvm::function_ref<void(SILInstruction *, LifetimeEnd end)> visit) {
-
-  AvailabilityBoundaryVisitor visitor(value);
-  AvailabilityBoundaryVisitor::Result result(value->getFunction());
-  visitor.visit(liveness, result, visit);
-
-  visitUsersOutsideLinearLivenessBoundary(
-      value, liveness, [&](auto *instruction) {
-        instruction->visitSubsequentInstructions([&](auto *next) {
-          visit(next, LifetimeEnd::Loop);
-          return true;
-        });
-      });
-}
-
-static bool endLifetimeAtAvailabilityBoundary(SILValue value,
-                                              const SSAPrunedLiveness &liveness,
-                                              DeadEndBlocks &deb) {
-  bool changed = false;
-  OSSALifetimeCompletion::visitAvailabilityBoundary(
-      value, liveness, [&](auto *unreachable, auto end) {
-        SILBuilderWithScope builder(unreachable);
-        endOSSALifetime(value, end, builder, deb);
-        changed = true;
-      });
-  return changed;
-}
-
-static bool endLifetimeAtBoundary(SILValue value,
-                                  SSAPrunedLiveness const &liveness,
-                                  OSSALifetimeCompletion::Boundary boundary,
-                                  DeadEndBlocks &deadEndBlocks) {
-  bool changed = false;
-  switch (boundary) {
-  case OSSALifetimeCompletion::Boundary::Liveness:
-    changed |= endLifetimeAtLivenessBoundary(value, liveness, deadEndBlocks);
-    break;
-  case OSSALifetimeCompletion::Boundary::Availability:
-    changed |=
-        endLifetimeAtAvailabilityBoundary(value, liveness, deadEndBlocks);
-    break;
-  }
-  return changed;
-}
-
-bool OSSALifetimeCompletion::analyzeAndUpdateLifetime(
-    ScopedAddressValue scopedAddress, Boundary boundary) {
-  SmallVector<SILBasicBlock *, 8> discoveredBlocks;
-  SSAPrunedLiveness liveness(scopedAddress->getFunction(), &discoveredBlocks);
-  liveness.initializeDef(scopedAddress.value);
-
-  struct Walker : TransitiveAddressWalker<Walker> {
-    OSSALifetimeCompletion &completion;
-    ScopedAddressValue scopedAddress;
-    Boundary boundary;
-    SSAPrunedLiveness &liveness;
-    Walker(OSSALifetimeCompletion &completion, ScopedAddressValue scopedAddress,
-           Boundary boundary, SSAPrunedLiveness &liveness)
-        : completion(completion), scopedAddress(scopedAddress),
-          boundary(boundary), liveness(liveness) {}
-    bool visitUse(Operand *use) {
-      auto *user = use->getUser();
-      if (scopedAddress.isScopeEndingUse(use)) {
-        liveness.updateForUse(user, /*lifetimeEnding=*/true);
-        return true;
-      }
-      liveness.updateForUse(user, /*lifetimeEnding=*/false);
-      for (auto result : user->getResults()) {
-        auto shouldComplete =
-            (bool)BorrowedValue(result) || (bool)ScopedAddressValue(result);
-        if (!shouldComplete)
-          continue;
-        auto completed = completion.completeOSSALifetime(result, boundary);
-        switch (completed) {
-        case LifetimeCompletion::NoLifetime:
-          break;
-        case LifetimeCompletion::AlreadyComplete:
-        case LifetimeCompletion::WasCompleted:
-          for (auto *consume : result->getConsumingUses()) {
-            liveness.updateForUse(consume->getUser(), /*lifetimeEnding=*/false);
-          }
-          break;
-        }
-      }
-      return true;
-    }
-  };
-  Walker walker(*this, scopedAddress, boundary, liveness);
-  AddressUseKind result = walker.walk(scopedAddress.value);
-  if (VerifyLifetimeCompletion && boundary != Boundary::Availability
-      && result != AddressUseKind::NonEscaping) {
-    llvm::errs() << "Incomplete liveness for:\n" << scopedAddress.value;
-    if (auto *escapingUse = walker.getEscapingUse()) {
-      llvm::errs() << "  escapes at:\n";
-      escapingUse->getUser()->printInContext(llvm::errs());
-    }
-    ASSERT(false && "caller must check for pointer escapes");
-  }
-  return endLifetimeAtBoundary(scopedAddress.value, liveness, boundary,
-                               deadEndBlocks);
-}
-
-/// End the lifetime of \p value at unreachable instructions.
-///
-/// Returns true if any new instructions were created to complete the lifetime.
-bool OSSALifetimeCompletion::analyzeAndUpdateLifetime(SILValue value,
-                                                      Boundary boundary) {
-  if (auto scopedAddress = ScopedAddressValue(value)) {
-    return analyzeAndUpdateLifetime(scopedAddress, boundary);
-  }
-  // Called for inner borrows, inner adjacent reborrows, inner reborrows, and
-  // scoped addresses.
-  auto handleInnerScope = [this, boundary](SILValue innerBorrowedValue) {
-    completeOSSALifetime(innerBorrowedValue, boundary);
-  };
-  if (value->getOwnershipKind() == OwnershipKind::None) {
-    // Trivial variable lifetimes are only relevant up to the extend_lifetime
-    // instructions emitted by SILGen. Their other uses have no meaning with
-    // respect to lifetime. The only purpose of "completing" their lifetime is
-    // to insert extend_lifetime on dead-end blocks.
-    LinearLiveness liveness(value);
-    liveness.compute();
-    return endLifetimeAtBoundary(value, liveness.getLiveness(), boundary,
-                                 deadEndBlocks);
-  }
-  InteriorLiveness liveness(value);
-  liveness.compute(domInfo, handleInnerScope);
-  if (VerifyLifetimeCompletion && boundary != Boundary::Availability
-      && liveness.getAddressUseKind() != AddressUseKind::NonEscaping) {
-    llvm::errs() << "Incomplete liveness for: " << value;
-    if (auto *escapingUse = liveness.escapingUse) {
-      llvm::errs() << "  escapes at:\n";
-      escapingUse->getUser()->printInContext(llvm::errs());
-    }
-    ASSERT(false && "caller must check for pointer escapes");
-  }
-  return endLifetimeAtBoundary(value, liveness.getLiveness(), boundary,
-                               deadEndBlocks);
-}
-
-namespace swift::test {
-// Arguments:
-// - SILValue: value
-// - string: either "liveness" or "availability"
-// Dumps:
-// - function
-static FunctionTest OSSALifetimeCompletionTest(
-    "ossa_lifetime_completion",
-    [](auto &function, auto &arguments, auto &test) {
-      SILValue value = arguments.takeValue();
-      OSSALifetimeCompletion::Boundary kind =
-          llvm::StringSwitch<OSSALifetimeCompletion::Boundary>(
-              arguments.takeString())
-              .Case("liveness", OSSALifetimeCompletion::Boundary::Liveness)
-              .Case("availability",
-                    OSSALifetimeCompletion::Boundary::Availability);
-      auto *deb = test.getDeadEndBlocks();
-      llvm::outs() << "OSSA lifetime completion on " << kind
-                   << " boundary: " << value;
-      OSSALifetimeCompletion completion(&function, /*domInfo*/ nullptr, *deb);
-      completion.completeOSSALifetime(value, kind);
-      function.print(llvm::outs());
-    });
-} // end namespace swift::test
-
-// TODO: create a fast check for 'mayEndLifetime(SILInstruction *)'. Verify that
-// it returns true for every instruction that has a lifetime-ending operand.
-void UnreachableLifetimeCompletion::visitUnreachableInst(
-    SILInstruction *instruction) {
-  auto *block = instruction->getParent();
-  bool inReachableBlock = !unreachableBlocks.contains(block);
-  // If this instruction's block is already marked unreachable, and
-  // updatingLifetimes is not yet set, then this instruction will be visited
-  // again later when propagating unreachable blocks.
-  if (!inReachableBlock && !updatingLifetimes)
-    return;
-
-  for (Operand &operand : instruction->getAllOperands()) {
-    if (!operand.isLifetimeEnding())
-      continue;
-
-    SILValue value = operand.get();
-    SILBasicBlock *defBlock = value->getParentBlock();
-    if (unreachableBlocks.contains(defBlock))
-      continue;
-
-    auto *def = value->getDefiningInstruction();
-    if (def && unreachableInsts.contains(def))
-      continue;
-
-    // The operand's definition is still reachable and its lifetime ends on a
-    // newly unreachable path.
-    //
-    // Note: The arguments of a no-return try_apply may still appear reachable
-    // here because the try_apply itself is never visited as unreachable, hence
-    // its successor blocks are not marked . But it
-    // seems harmless to recompute their lifetimes.
-
-    // Insert this unreachable instruction in unreachableInsts if its parent
-    // block is not already marked unreachable.
-    if (inReachableBlock) {
-      unreachableInsts.insert(instruction);
-    }
-    incompleteValues.insert(value);
-
-    // Add unreachable successors to the forward traversal worklist.
-    if (auto *term = dyn_cast<TermInst>(instruction)) {
-      for (auto *succBlock : term->getSuccessorBlocks()) {
-        if (llvm::all_of(succBlock->getPredecessorBlocks(),
-                         [&](SILBasicBlock *predBlock) {
-                           if (predBlock == block)
-                             return true;
-
-                           return unreachableBlocks.contains(predBlock);
-                         })) {
-          unreachableBlocks.insert(succBlock);
-        }
-      }
-    }
-  }
-}
-
-bool UnreachableLifetimeCompletion::completeLifetimes() {
-  assert(!updatingLifetimes && "don't call this more than once");
-  updatingLifetimes = true;
-
-  // Now that all unreachable terminator instructions have been visited,
-  // propagate unreachable blocks.
-  for (auto blockIt = unreachableBlocks.begin();
-       blockIt != unreachableBlocks.end(); ++blockIt) {
-    auto *block = *blockIt;
-    for (auto &instruction : *block) {
-      visitUnreachableInst(&instruction);
-    }
-  }
-
-  OSSALifetimeCompletion completion(function, domInfo, deadEndBlocks);
-
-  bool changed = false;
-  for (auto value : incompleteValues) {
-    if (completion.completeOSSALifetime(
-            value, OSSALifetimeCompletion::Boundary::Availability) ==
-        LifetimeCompletion::WasCompleted) {
-      changed = true;
-    }
-  }
-  return changed;
-}
diff --git a/lib/SIL/Utils/OwnershipUtils.cpp b/lib/SIL/Utils/OwnershipUtils.cpp
index f600c2800a045..9d00d013ca6df 100644
--- a/lib/SIL/Utils/OwnershipUtils.cpp
+++ b/lib/SIL/Utils/OwnershipUtils.cpp
@@ -975,8 +975,9 @@ computeTransitiveLiveness(MultiDefPrunedLiveness &liveness) const {
   });
 }
 
-bool BorrowedValue::areUsesWithinExtendedScope(
-    ArrayRef<Operand *> uses, DeadEndBlocks *deadEndBlocks) const {
+template <typename Instructions>
+bool BorrowedValue::areWithinExtendedScope(Instructions insts,
+                                           DeadEndBlocks *deadEndBlocks) const {
   // First make sure that we actually have a local scope. If we have a non-local
   // scope, then we have something (like a SILFunctionArgument) where a larger
   // semantic construct (in the case of SILFunctionArgument, the function
@@ -988,7 +989,20 @@ bool BorrowedValue::areUsesWithinExtendedScope(
   // Compute the local scope's liveness.
   MultiDefPrunedLiveness liveness(value->getFunction());
   computeTransitiveLiveness(liveness);
-  return liveness.areUsesWithinBoundary(uses, deadEndBlocks);
+  return liveness.areWithinBoundary(insts, deadEndBlocks);
+}
+
+template bool BorrowedValue::areWithinExtendedScope<UsePointInstructionRange>(
+    UsePointInstructionRange insts, DeadEndBlocks *deadEndBlocks) const;
+
+template bool
+BorrowedValue::areWithinExtendedScope<SILInstruction::OperandUserRange>(
+    SILInstruction::OperandUserRange insts, DeadEndBlocks *deadEndBlocks) const;
+
+bool BorrowedValue::areUsesWithinExtendedScope(
+    ArrayRef<Operand *> uses, DeadEndBlocks *deadEndBlocks) const {
+  SILInstruction::OperandUserRange users(uses, SILInstruction::OperandToUser());
+  return areWithinExtendedScope(users, deadEndBlocks);
 }
 
 // The visitor \p func is only called on final scope-ending uses, not reborrows.
diff --git a/lib/SIL/Utils/PrunedLiveness.cpp b/lib/SIL/Utils/PrunedLiveness.cpp
index 6e8e777cb06ad..a0eb8871dbccc 100644
--- a/lib/SIL/Utils/PrunedLiveness.cpp
+++ b/lib/SIL/Utils/PrunedLiveness.cpp
@@ -796,14 +796,8 @@ static FunctionTest SSAPrunedLiveness__areUsesWithinBoundary(
 template <typename LivenessWithDefs>
 bool PrunedLiveRange<LivenessWithDefs>::areUsesWithinBoundary(
     ArrayRef<Operand *> uses, DeadEndBlocks *deadEndBlocks) const {
-  assert(asImpl().isInitialized());
-
-  for (auto *use : uses) {
-    auto *user = use->getUser();
-    if (!isWithinBoundary(user, deadEndBlocks))
-      return false;
-  }
-  return true;
+  SILInstruction::OperandUserRange users(uses, SILInstruction::OperandToUser());
+  return areWithinBoundary(users, deadEndBlocks);
 }
 
 template <typename LivenessWithDefs>
diff --git a/lib/SIL/Utils/SILBridging.cpp b/lib/SIL/Utils/SILBridging.cpp
index 15c8cf64ff238..b4f9c97941ae9 100644
--- a/lib/SIL/Utils/SILBridging.cpp
+++ b/lib/SIL/Utils/SILBridging.cpp
@@ -20,6 +20,9 @@
 #include "swift/AST/Attr.h"
 #include "swift/AST/SemanticAttrs.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/SIL/SILContext.h"
+#include "swift/SIL/SILCloner.h"
+#include "swift/SIL/TypeSubstCloner.h"
 #include "swift/SIL/MemAccessUtils.h"
 #include "swift/SIL/OwnershipUtils.h"
 #include "swift/SIL/ParseTestSpecification.h"
@@ -50,8 +53,10 @@ bool swiftModulesInitialized() {
 SwiftMetatype SILNode::getSILNodeMetatype(SILNodeKind kind) {
   SwiftMetatype metatype = nodeMetatypes[(unsigned)kind];
   if (nodeMetatypesInitialized && !metatype) {
-    llvm::errs() << "Instruction " << getSILInstructionName((SILInstructionKind)kind) << " not registered\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "Instruction " << getSILInstructionName((SILInstructionKind)kind)
+          << " not registered";
+    });
   }
   return metatype;
 }
@@ -103,16 +108,18 @@ void registerBridgedClass(BridgedStringRef bridgedClassName, SwiftMetatype metat
     prefixedName = std::string("SIL") + std::string(className);
     iter = valueNamesToKind.find(prefixedName);
     if (iter == valueNamesToKind.end()) {
-      llvm::errs() << "Unknown bridged node class " << className << '\n';
-      abort();
+      ABORT([&](auto &out) {
+        out << "Unknown bridged node class " << className;
+      });
     }
     className = prefixedName;
   }
   SILNodeKind kind = iter->second;
   SwiftMetatype existingTy = nodeMetatypes[(unsigned)kind];
   if (existingTy) {
-    llvm::errs() << "Double registration of class " << className << '\n';
-    abort();
+    ABORT([&](auto &out) {
+      out << "Double registration of class " << className;
+    });
   }
   nodeMetatypes[(unsigned)kind] = metatype;
 }
@@ -121,9 +128,9 @@ void registerBridgedClass(BridgedStringRef bridgedClassName, SwiftMetatype metat
 //                                Test
 //===----------------------------------------------------------------------===//
 
-void registerFunctionTest(BridgedStringRef name, void *nativeSwiftInvocation) {
+void registerTest(BridgedStringRef name, void *nativeSwiftContext) {
   swift::test::FunctionTest::createNativeSwiftFunctionTest(
-      name.unbridged(), nativeSwiftInvocation);
+      name.unbridged(), nativeSwiftContext, /*isSILTest=*/ true);
 }
 
 bool BridgedTestArguments::hasUntaken() const {
@@ -179,11 +186,16 @@ static_assert((int)BridgedFunction::PerformanceConstraints::NoLocks == (int)swif
 static_assert((int)BridgedFunction::PerformanceConstraints::NoRuntime == (int)swift::PerformanceConstraints::NoRuntime);
 static_assert((int)BridgedFunction::PerformanceConstraints::NoExistentials == (int)swift::PerformanceConstraints::NoExistentials);
 static_assert((int)BridgedFunction::PerformanceConstraints::NoObjCBridging == (int)swift::PerformanceConstraints::NoObjCBridging);
+static_assert((int)BridgedFunction::PerformanceConstraints::ManualOwnership == (int)swift::PerformanceConstraints::ManualOwnership);
 
 static_assert((int)BridgedFunction::InlineStrategy::InlineDefault == (int)swift::InlineDefault);
 static_assert((int)BridgedFunction::InlineStrategy::NoInline == (int)swift::NoInline);
+static_assert((int)BridgedFunction::InlineStrategy::HeuristicAlwaysInline == (int)swift::HeuristicAlwaysInline);
 static_assert((int)BridgedFunction::InlineStrategy::AlwaysInline == (int)swift::AlwaysInline);
 
+static_assert((int)BridgedFunction::ABILanguage::Swift == (int)swift::SILFunctionLanguage::Swift);
+static_assert((int)BridgedFunction::ABILanguage::C == (int)swift::SILFunctionLanguage::C);
+
 static_assert((int)BridgedFunction::ThunkKind::IsNotThunk == (int)swift::IsNotThunk);
 static_assert((int)BridgedFunction::ThunkKind::IsThunk == (int)swift::IsThunk);
 static_assert((int)BridgedFunction::ThunkKind::IsReabstractionThunk == (int)swift::IsReabstractionThunk);
@@ -197,15 +209,44 @@ BridgedOwnedString BridgedFunction::getDebugDescription() const {
   return BridgedOwnedString(str);
 }
 
-BridgedSubstitutionMap BridgedFunction::getMethodSubstitutions(BridgedSubstitutionMap contextSubs) const {
+BridgedSubstitutionMap BridgedFunction::getMethodSubstitutions(BridgedSubstitutionMap contextSubstitutions,
+                                                               BridgedCanType selfType) const {
   swift::SILFunction *f = getFunction();
   swift::GenericSignature genericSig = f->getLoweredFunctionType()->getInvocationGenericSignature();
 
   if (!genericSig || genericSig->areAllParamsConcrete())
     return swift::SubstitutionMap();
 
+  SubstitutionMap contextSubs = contextSubstitutions.unbridged();
+  if (selfType.unbridged() &&
+      contextSubs.getGenericSignature().getGenericParams().size() + 1 == genericSig.getGenericParams().size()) {
+
+    // If this is a default witness methods (`selfType` != nil) it has generic self type. In this case
+    // the generic self parameter is at depth 0 and the actual generic parameters of the substitution map
+    // are at depth + 1, e.g:
+    // ```
+    //     @convention(witness_method: P) <τ_0_0><τ_1_0 where τ_0_0 : GenClass<τ_1_0>.T>
+    //                                       ^      ^
+    //                                    self      params of substitution map at depth + 1
+    // ```
+    return swift::SubstitutionMap::get(genericSig,
+      [&](SubstitutableType *type) -> Type {
+        GenericTypeParamType *genericParam = cast<GenericTypeParamType>(type);
+        // The self type is τ_0_0
+        if (genericParam->getDepth() == 0 && genericParam->getIndex() == 0)
+          return selfType.unbridged();
+
+        // Lookup the substitution map types at depth - 1.
+        auto *depthMinus1Param = GenericTypeParamType::getType(genericParam->getDepth() - 1,
+                                                               genericParam->getIndex(),
+                                                               genericParam->getASTContext());
+        return swift::QuerySubstitutionMap{contextSubs}(depthMinus1Param);
+      },
+      swift::LookUpConformanceInModule());
+
+  }
   return swift::SubstitutionMap::get(genericSig,
-                                     swift::QuerySubstitutionMap{contextSubs.unbridged()},
+                                     swift::QuerySubstitutionMap{contextSubs},
                                      swift::LookUpConformanceInModule());
 }
 
@@ -318,10 +359,10 @@ bool BridgedGlobalVar::canBeInitializedStatically() const {
   if (hasPublicVisibility(global->getLinkage()))
     expansion = ResilienceExpansion::Minimal;
 
-  auto &tl = global->getModule().Types.getTypeLowering(
+  auto props = global->getModule().Types.getTypeProperties(
       global->getLoweredType(),
       TypeExpansionContext::noOpaqueTypeArchetypesSubstitution(expansion));
-  return tl.isLoadable();
+  return props.isFixedABI();
 }
 
 bool BridgedGlobalVar::mustBeInitializedStatically() const {
@@ -509,3 +550,376 @@ BridgedInstruction BridgedBuilder::createSwitchEnumAddrInst(BridgedValue enumAdd
                                            defaultBlock.unbridged(),
                                            convertCases(enumAddr.getSILValue()->getType(), enumCases, numEnumCases))};
 }
+
+//===----------------------------------------------------------------------===//
+//                               BridgedCloner
+//===----------------------------------------------------------------------===//
+
+// Need to put the cloner Impl classes into namespace swift to forward reference it from SILBridging.h.
+namespace swift {
+
+class BridgedClonerImpl : public SILCloner<BridgedClonerImpl> {
+  friend class SILInstructionVisitor<BridgedClonerImpl>;
+  friend class SILCloner<BridgedClonerImpl>;
+
+  bool hasFixedLocation;
+  union {
+    SILDebugLocation fixedLocation;
+    ScopeCloner scopeCloner;
+  };
+
+  SILInstruction *result = nullptr;
+
+public:
+  BridgedClonerImpl(SILGlobalVariable *gVar)
+    : SILCloner<BridgedClonerImpl>(gVar),
+      hasFixedLocation(true),
+      fixedLocation(ArtificialUnreachableLocation(), nullptr) {}
+
+  BridgedClonerImpl(SILInstruction *insertionPoint)
+    : SILCloner<BridgedClonerImpl>(*insertionPoint->getFunction()),
+      hasFixedLocation(true),
+      fixedLocation(insertionPoint->getDebugLocation()) {
+    Builder.setInsertionPoint(insertionPoint);
+  }
+
+  BridgedClonerImpl(SILFunction &emptyFunction)
+    : SILCloner<BridgedClonerImpl>(emptyFunction),
+      hasFixedLocation(false),
+      scopeCloner(ScopeCloner(emptyFunction)) {}
+
+  ~BridgedClonerImpl() {
+    if (hasFixedLocation) {
+      fixedLocation.~SILDebugLocation();
+    } else {
+      scopeCloner.~ScopeCloner();
+    }
+  }
+
+  SILValue getClonedValue(SILValue v) {
+    return getMappedValue(v);
+  }
+
+  SILInstruction *cloneInst(SILInstruction *inst) {
+    result = nullptr;
+    visit(inst);
+    ASSERT(result && "instruction not cloned");
+    return result;
+  }
+
+  SILLocation remapLocation(SILLocation loc) {
+    if (hasFixedLocation)
+      return fixedLocation.getLocation();
+    return loc;
+  }
+
+  const SILDebugScope *remapScope(const SILDebugScope *DS) {
+    if (hasFixedLocation)
+      return fixedLocation.getScope();
+    return scopeCloner.getOrCreateClonedScope(DS);
+  }
+
+  void postProcess(SILInstruction *Orig, SILInstruction *Cloned) {
+    result = Cloned;
+    SILCloner<BridgedClonerImpl>::postProcess(Orig, Cloned);
+  }
+};
+
+class BridgedTypeSubstClonerImpl : public TypeSubstCloner<BridgedTypeSubstClonerImpl> {
+  SILInstruction *result = nullptr;
+
+public:
+  BridgedTypeSubstClonerImpl(SILFunction &from, SILFunction &toEmptyFunction, SubstitutionMap subs)
+    : TypeSubstCloner<BridgedTypeSubstClonerImpl>(toEmptyFunction, from, subs) {}
+
+  SILValue getClonedValue(SILValue v) {
+    return getMappedValue(v);
+  }
+
+  SILInstruction *cloneInst(SILInstruction *inst) {
+    result = nullptr;
+    visit(inst);
+    ASSERT(result && "instruction not cloned");
+    return result;
+  }
+
+  void postProcess(SILInstruction *Orig, SILInstruction *Cloned) {
+    result = Cloned;
+    SILClonerWithScopes<BridgedTypeSubstClonerImpl>::postProcess(Orig, Cloned);
+  }
+
+  SILFunction *getOriginal() { return &Original; }
+};
+
+} // namespace swift
+
+BridgedCloner::BridgedCloner(BridgedGlobalVar var, BridgedContext context)
+  : cloner(new BridgedClonerImpl(var.getGlobal())) {
+  context.context->notifyNewCloner();
+}
+
+BridgedCloner::BridgedCloner(BridgedInstruction inst,
+                             BridgedContext context)
+    : cloner(new BridgedClonerImpl(inst.unbridged())) {
+  context.context->notifyNewCloner();
+}
+
+BridgedCloner::BridgedCloner(BridgedFunction emptyFunction, BridgedContext context)
+  : cloner(new BridgedClonerImpl(*emptyFunction.getFunction())) {
+  context.context->notifyNewCloner();
+}
+
+void BridgedCloner::destroy(BridgedContext context) {
+  delete cloner;
+  cloner = nullptr;
+  context.context->notifyClonerDestroyed();
+}
+
+BridgedFunction BridgedCloner::getCloned() const {
+  return { &cloner->getBuilder().getFunction() };
+}
+
+BridgedValue BridgedCloner::getClonedValue(BridgedValue v) {
+  return {cloner->getClonedValue(v.getSILValue())};
+}
+
+bool BridgedCloner::isValueCloned(BridgedValue v) const {
+  return cloner->isValueCloned(v.getSILValue());
+}
+
+void BridgedCloner::recordClonedInstruction(BridgedInstruction origInst, BridgedInstruction clonedInst) const {
+  cloner->recordClonedInstruction(origInst.unbridged(), clonedInst.unbridged());
+}
+
+void BridgedCloner::recordFoldedValue(BridgedValue orig, BridgedValue mapped) const {
+  cloner->recordFoldedValue(orig.getSILValue(), mapped.getSILValue());
+}
+
+BridgedInstruction BridgedCloner::clone(BridgedInstruction inst) const {
+  return {cloner->cloneInst(inst.unbridged())->asSILNode()};
+}
+
+void BridgedCloner::setInsertionBlockIfNotSet(BridgedBasicBlock block) const {
+  if (!cloner->getBuilder().hasValidInsertionPoint())
+    cloner->getBuilder().setInsertionPoint(block.unbridged());
+}
+
+BridgedBasicBlock BridgedCloner::getClonedBasicBlock(BridgedBasicBlock originalBasicBlock) const {
+  return { cloner->getOpBasicBlock(originalBasicBlock.unbridged()) };
+}
+
+void BridgedCloner::cloneFunctionBody(BridgedFunction originalFunction,
+                                      BridgedBasicBlock clonedEntryBlock,
+                                      BridgedValueArray clonedEntryBlockArgs) const {
+  llvm::SmallVector<swift::SILValue, 16> clonedEntryBlockArgsStorage;
+  auto clonedEntryBlockArgsArrayRef = clonedEntryBlockArgs.getValues(clonedEntryBlockArgsStorage);
+  cloner->cloneFunctionBody(originalFunction.getFunction(), clonedEntryBlock.unbridged(), clonedEntryBlockArgsArrayRef);
+}
+
+void BridgedCloner::cloneFunctionBody(BridgedFunction originalFunction) const {
+  cloner->cloneFunction(originalFunction.getFunction());
+}
+
+BridgedTypeSubstCloner::BridgedTypeSubstCloner(BridgedFunction fromFunction, BridgedFunction toFunction,
+                                               BridgedSubstitutionMap substitutions,
+                                               BridgedContext context)
+  : cloner(new BridgedTypeSubstClonerImpl(*fromFunction.getFunction(), *toFunction.getFunction(),
+                                          substitutions.unbridged())) {
+  context.context->notifyNewCloner();
+}
+
+void BridgedTypeSubstCloner::destroy(BridgedContext context) {
+  delete cloner;
+  cloner = nullptr;
+  context.context->notifyClonerDestroyed();
+}
+
+void BridgedTypeSubstCloner::cloneFunctionBody() const {
+  cloner->cloneFunction(cloner->getOriginal());
+}
+
+BridgedBasicBlock BridgedTypeSubstCloner::getClonedBasicBlock(BridgedBasicBlock originalBasicBlock) const {
+  return { cloner->getOpBasicBlock(originalBasicBlock.unbridged()) };
+}
+
+BridgedValue BridgedTypeSubstCloner::getClonedValue(BridgedValue v) {
+  return {cloner->getClonedValue(v.getSILValue())};
+}
+
+//===----------------------------------------------------------------------===//
+//                               BridgedContext
+//===----------------------------------------------------------------------===//
+
+BridgedOwnedString BridgedContext::getModuleDescription() const {
+  std::string str;
+  llvm::raw_string_ostream os(str);
+  context->getModule()->print(os);
+  str.pop_back(); // Remove trailing newline.
+  return BridgedOwnedString(str);
+}
+
+OptionalBridgedFunction BridgedContext::lookUpNominalDeinitFunction(BridgedDeclObj nominal)  const {
+  return {context->getModule()->lookUpMoveOnlyDeinitFunction(nominal.getAs<swift::NominalTypeDecl>())};
+}
+
+BridgedFunction BridgedContext::
+createEmptyFunction(BridgedStringRef name,
+                    const BridgedParameterInfo * _Nullable bridgedParams,
+                    SwiftInt paramCount,
+                    bool hasSelfParam,
+                    BridgedFunction fromFunc) const {
+  llvm::SmallVector<SILParameterInfo> params;
+  for (unsigned idx = 0; idx < paramCount; ++idx) {
+    params.push_back(bridgedParams[idx].unbridged());
+  }
+  return {context->createEmptyFunction(name.unbridged(), params, hasSelfParam, fromFunc.getFunction())};
+}
+
+BridgedGlobalVar BridgedContext::createGlobalVariable(BridgedStringRef name, BridgedType type,
+                                                      BridgedLinkage linkage,
+                                                      bool isLet,
+                                                      bool markedAsUsed) const {
+  auto *global = SILGlobalVariable::create(
+      *context->getModule(),
+      (swift::SILLinkage)linkage, IsNotSerialized,
+      name.unbridged(), type.unbridged());
+  if (isLet)
+    global->setLet(true);
+  global->setMarkedAsUsed(markedAsUsed);
+  return {global};
+}
+
+void BridgedContext::moveFunctionBody(BridgedFunction sourceFunc, BridgedFunction destFunc) const {
+  context->moveFunctionBody(sourceFunc.getFunction(), destFunc.getFunction());
+}
+
+//===----------------------------------------------------------------------===//
+//                           SILContext
+//===----------------------------------------------------------------------===//
+
+SILContext::~SILContext() {}
+
+void SILContext::verifyEverythingIsCleared() {
+  ASSERT(allocatedSlabs.empty() && "StackList is leaking slabs");
+  ASSERT(numBlockSetsAllocated == 0 && "Not all BasicBlockSets deallocated");
+  ASSERT(numNodeSetsAllocated == 0 && "Not all NodeSets deallocated");
+  ASSERT(numOperandSetsAllocated == 0 && "Not all OperandSets deallocated");
+  ASSERT(numClonersAllocated == 0 && "Not all cloners deallocated");
+}
+
+FixedSizeSlab *SILContext::allocSlab(FixedSizeSlab *afterSlab) {
+  FixedSizeSlab *slab = getModule()->allocSlab();
+  if (afterSlab) {
+    allocatedSlabs.insert(std::next(afterSlab->getIterator()), *slab);
+  } else {
+    allocatedSlabs.push_back(*slab);
+  }
+  return slab;
+}
+
+FixedSizeSlab *SILContext::freeSlab(FixedSizeSlab *slab) {
+  FixedSizeSlab *prev = nullptr;
+  assert(!allocatedSlabs.empty());
+  if (&allocatedSlabs.front() != slab)
+    prev = &*std::prev(slab->getIterator());
+
+  allocatedSlabs.remove(*slab);
+  getModule()->freeSlab(slab);
+  return prev;
+}
+
+BasicBlockSet *SILContext::allocBlockSet() {
+  ASSERT(numBlockSetsAllocated < BlockSetCapacity &&
+         "too many BasicBlockSets allocated");
+
+  auto *storage = (BasicBlockSet *)blockSetStorage + numBlockSetsAllocated;
+  BasicBlockSet *set = new (storage) BasicBlockSet(function);
+  aliveBlockSets[numBlockSetsAllocated] = true;
+  ++numBlockSetsAllocated;
+  return set;
+}
+
+void SILContext::freeBlockSet(BasicBlockSet *set) {
+  int idx = set - (BasicBlockSet *)blockSetStorage;
+  assert(idx >= 0 && idx < numBlockSetsAllocated);
+  assert(aliveBlockSets[idx] && "double free of BasicBlockSet");
+  aliveBlockSets[idx] = false;
+
+  while (numBlockSetsAllocated > 0 && !aliveBlockSets[numBlockSetsAllocated - 1]) {
+    auto *set = (BasicBlockSet *)blockSetStorage + numBlockSetsAllocated - 1;
+    set->~BasicBlockSet();
+    --numBlockSetsAllocated;
+  }
+}
+
+NodeSet *SILContext::allocNodeSet() {
+  ASSERT(numNodeSetsAllocated < NodeSetCapacity &&
+         "too many NodeSets allocated");
+
+  auto *storage = (NodeSet *)nodeSetStorage + numNodeSetsAllocated;
+  NodeSet *set = new (storage) NodeSet(function);
+  aliveNodeSets[numNodeSetsAllocated] = true;
+  ++numNodeSetsAllocated;
+  return set;
+}
+
+void SILContext::freeNodeSet(NodeSet *set) {
+  int idx = set - (NodeSet *)nodeSetStorage;
+  assert(idx >= 0 && idx < numNodeSetsAllocated);
+  assert(aliveNodeSets[idx] && "double free of NodeSet");
+  aliveNodeSets[idx] = false;
+
+  while (numNodeSetsAllocated > 0 && !aliveNodeSets[numNodeSetsAllocated - 1]) {
+    auto *set = (NodeSet *)nodeSetStorage + numNodeSetsAllocated - 1;
+    set->~NodeSet();
+    --numNodeSetsAllocated;
+  }
+}
+
+OperandSet *SILContext::allocOperandSet() {
+  ASSERT(numOperandSetsAllocated < OperandSetCapacity &&
+         "too many OperandSets allocated");
+
+  auto *storage = (OperandSet *)operandSetStorage + numOperandSetsAllocated;
+  OperandSet *set = new (storage) OperandSet(function);
+  aliveOperandSets[numOperandSetsAllocated] = true;
+  ++numOperandSetsAllocated;
+  return set;
+}
+
+void SILContext::freeOperandSet(OperandSet *set) {
+  int idx = set - (OperandSet *)operandSetStorage;
+  assert(idx >= 0 && idx < numOperandSetsAllocated);
+  assert(aliveOperandSets[idx] && "double free of OperandSet");
+  aliveOperandSets[idx] = false;
+
+  while (numOperandSetsAllocated > 0 && !aliveOperandSets[numOperandSetsAllocated - 1]) {
+    auto *set = (OperandSet *)operandSetStorage + numOperandSetsAllocated - 1;
+    set->~OperandSet();
+    --numOperandSetsAllocated;
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//                           BridgedVerifier
+//===----------------------------------------------------------------------===//
+
+static BridgedVerifier::VerifyFunctionFn verifyFunctionFunction = nullptr;
+
+void BridgedVerifier::registerVerifier(VerifyFunctionFn verifyFunctionFn) {
+  verifyFunctionFunction = verifyFunctionFn;
+}
+
+void BridgedVerifier::runSwiftFunctionVerification(SILFunction * _Nonnull f, SILContext * _Nonnull context) {
+  if (!verifyFunctionFunction)
+    return;
+
+  verifyFunctionFunction({context}, {f});
+}
+
+void BridgedVerifier::verifierError(BridgedStringRef message,
+                                    OptionalBridgedInstruction atInstruction,
+                                    OptionalBridgedArgument atArgument) {
+  Twine msg(message.unbridged());
+  verificationFailure(msg, atInstruction.unbridged(), atArgument.unbridged(), /*extraContext=*/nullptr);
+}
diff --git a/lib/SIL/Utils/Test.cpp b/lib/SIL/Utils/Test.cpp
index 4a9eb94a6d61c..2c3d7911d068f 100644
--- a/lib/SIL/Utils/Test.cpp
+++ b/lib/SIL/Utils/Test.cpp
@@ -27,7 +27,8 @@ namespace {
 
 class Registry {
   StringMap<FunctionTest> registeredTests;
-  SwiftNativeFunctionTestThunk thunk;
+  SwiftNativeFunctionTestThunk functionTestThunk;
+  SwiftNativeFunctionTestThunk silTestThunk;
 
 public:
   static Registry &get() {
@@ -41,11 +42,17 @@ class Registry {
     (void)inserted;
   }
 
+
   void registerFunctionTestThunk(SwiftNativeFunctionTestThunk thunk) {
-    this->thunk = thunk;
+    this->functionTestThunk = thunk;
+  }
+
+  void registerTestThunk(SwiftNativeFunctionTestThunk thunk) {
+    this->silTestThunk = thunk;
   }
 
-  SwiftNativeFunctionTestThunk getFunctionTestThunk() { return thunk; }
+  SwiftNativeFunctionTestThunk getFunctionTestThunk() { return functionTestThunk; }
+  SwiftNativeFunctionTestThunk getSILTestThunk() { return silTestThunk; }
 
   FunctionTest getFunctionTest(StringRef name) {
     auto iter = registeredTests.find(name);
@@ -75,18 +82,23 @@ void registerFunctionTestThunk(SwiftNativeFunctionTestThunk thunk) {
   Registry::get().registerFunctionTestThunk(thunk);
 }
 
+void registerTestThunk(SwiftNativeFunctionTestThunk thunk) {
+  Registry::get().registerTestThunk(thunk);
+}
+
 FunctionTest::FunctionTest(StringRef name, Invocation invocation)
     : invocation(invocation), pass(nullptr), function(nullptr),
       dependencies(nullptr) {
   Registry::get().registerFunctionTest(*this, name);
 }
-FunctionTest::FunctionTest(StringRef name, NativeSwiftInvocation invocation)
-    : invocation(invocation), pass(nullptr), function(nullptr),
-      dependencies(nullptr) {}
+FunctionTest::FunctionTest(StringRef name, NativeSwiftInvocation invocation,
+                           bool isSILTest)
+    : invocation(invocation), isSwiftSILTest(isSILTest), pass(nullptr),
+      function(nullptr), dependencies(nullptr) {}
 
 void FunctionTest::createNativeSwiftFunctionTest(
-    StringRef name, NativeSwiftInvocation invocation) {
-  Registry::get().registerFunctionTest({name, invocation}, name);
+    StringRef name, NativeSwiftInvocation invocation, bool isSILTest) {
+  Registry::get().registerFunctionTest({name, invocation, isSILTest}, name);
 }
 
 FunctionTest FunctionTest::get(StringRef name) {
@@ -104,8 +116,9 @@ void FunctionTest::run(SILFunction &function, Arguments &arguments,
   } else {
     llvm::outs().flush();
     auto *fn = invocation.get<NativeSwiftInvocation>();
-    Registry::get().getFunctionTestThunk()(fn, {&function}, {&arguments},
-                                           {getSwiftPassInvocation()});
+    auto thunk = isSwiftSILTest ? Registry::get().getSILTestThunk()
+                                : Registry::get().getFunctionTestThunk();
+    thunk(fn, {&function}, {&arguments}, {getSILContext()});
     fflush(stdout);
   }
   this->pass = nullptr;
@@ -125,6 +138,6 @@ SILPassManager *FunctionTest::getPassManager() {
   return dependencies->getPassManager();
 }
 
-SwiftPassInvocation *FunctionTest::getSwiftPassInvocation() {
-  return dependencies->getSwiftPassInvocation();
+SILContext *FunctionTest::getSILContext() {
+  return dependencies->getSILContext();
 }
diff --git a/lib/SIL/Verifier/MemoryLifetimeVerifier.cpp b/lib/SIL/Verifier/MemoryLifetimeVerifier.cpp
index d83fc493224d9..0ee5cd00f3d5b 100644
--- a/lib/SIL/Verifier/MemoryLifetimeVerifier.cpp
+++ b/lib/SIL/Verifier/MemoryLifetimeVerifier.cpp
@@ -12,13 +12,14 @@
 
 #define DEBUG_TYPE "sil-memory-lifetime-verifier"
 #include "swift/Basic/Assertions.h"
-#include "swift/SIL/MemoryLocations.h"
+#include "swift/SIL/ApplySite.h"
+#include "swift/SIL/BasicBlockDatastructures.h"
+#include "swift/SIL/BasicBlockUtils.h"
 #include "swift/SIL/BitDataflow.h"
 #include "swift/SIL/CalleeCache.h"
+#include "swift/SIL/MemoryLocations.h"
 #include "swift/SIL/SILBasicBlock.h"
 #include "swift/SIL/SILFunction.h"
-#include "swift/SIL/ApplySite.h"
-#include "swift/SIL/BasicBlockDatastructures.h"
 #include "llvm/Support/CommandLine.h"
 
 using namespace swift;
@@ -43,6 +44,7 @@ class MemoryLifetimeVerifier {
 
   SILFunction *function;
   CalleeCache *calleeCache;
+  DeadEndBlocks *deadEndBlocks;
   MemoryLocations locations;
 
   /// alloc_stack memory locations which are used for store_borrow.
@@ -140,11 +142,12 @@ class MemoryLifetimeVerifier {
   }
 
 public:
-  MemoryLifetimeVerifier(SILFunction *function, CalleeCache *calleeCache) :
-    function(function),
-    calleeCache(calleeCache),
-    locations(/*handleNonTrivialProjections*/ true,
-              /*handleTrivialLocations*/ true) {}
+  MemoryLifetimeVerifier(SILFunction *function, CalleeCache *calleeCache,
+                         DeadEndBlocks *deadEndBlocks)
+      : function(function), calleeCache(calleeCache),
+        deadEndBlocks(deadEndBlocks),
+        locations(/*handleNonTrivialProjections*/ true,
+                  /*handleTrivialLocations*/ true) {}
 
   /// The main entry point to verify the lifetime of all memory locations in
   /// the function.
@@ -259,9 +262,10 @@ void MemoryLifetimeVerifier::reportError(const Twine &complaint,
   if (DontAbortOnMemoryLifetimeErrors)
     return;
 
-  llvm::errs() << "in function:\n";
-  function->print(llvm::errs());
-  abort();
+  ABORT([&](auto &out) {
+    out << "in function:\n";
+    function->print(out);
+  });
 }
 
 void MemoryLifetimeVerifier::require(const Bits &wrongBits,
@@ -883,7 +887,12 @@ void MemoryLifetimeVerifier::checkBlock(SILBasicBlock *block, Bits &bits) {
       }
       case SILInstructionKind::DeallocStackInst: {
         SILValue opVal = cast<DeallocStackInst>(&I)->getOperand();
-        requireBitsClear(bits & nonTrivialLocations, opVal, &I);
+        if (!deadEndBlocks->isDeadEnd(I.getParent())) {
+          // TODO: rdar://159311784: Maybe at some point the invariant will be
+          //                         enforced that values stored into addresses
+          //                         don't leak in dead-ends.
+          requireBitsClear(bits & nonTrivialLocations, opVal, &I);
+        }
         // Needed to clear any bits of trivial locations (which are not required
         // to be zero).
         locations.clearBits(bits, opVal);
@@ -973,7 +982,8 @@ void MemoryLifetimeVerifier::verify() {
 
 } // anonymous namespace
 
-void SILFunction::verifyMemoryLifetime(CalleeCache *calleeCache) {
-  MemoryLifetimeVerifier verifier(this, calleeCache);
+void SILFunction::verifyMemoryLifetime(CalleeCache *calleeCache,
+                                       DeadEndBlocks *deadEndBlocks) {
+  MemoryLifetimeVerifier verifier(this, calleeCache, deadEndBlocks);
   verifier.verify();
 }
diff --git a/lib/SIL/Verifier/SILOwnershipVerifier.cpp b/lib/SIL/Verifier/SILOwnershipVerifier.cpp
index a109a1a71dc90..9ada227b9b268 100644
--- a/lib/SIL/Verifier/SILOwnershipVerifier.cpp
+++ b/lib/SIL/Verifier/SILOwnershipVerifier.cpp
@@ -20,6 +20,7 @@
 #include "swift/AST/Decl.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/Module.h"
+#include "swift/AST/SemanticAttrs.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/Range.h"
@@ -658,6 +659,15 @@ bool SILValueOwnershipChecker::checkValueWithoutLifetimeEndingUses(
     }
   }
 
+  if (auto *uoc = dyn_cast<UncheckedOwnershipConversionInst>(value)) {
+    // When converting from `unowned`, which can happen for ObjectiveC blocks,
+    // we don't require and scope-ending instruction. This falls in the category:
+    // "trust me, I know what I'm doing".
+    if (uoc->getOperand()->getOwnershipKind() == OwnershipKind::Unowned) {
+      return true;
+    }
+  }
+
   // If we have an unowned value, then again there is nothing left to do.
   if (value->getOwnershipKind() == OwnershipKind::Unowned)
     return true;
@@ -857,6 +867,14 @@ void SILInstruction::verifyOperandOwnership(
     return;
 #endif
 
+  if (getModule().getOptions().VerifyNone) {
+    return;
+  }
+
+  if (getFunction()->hasSemanticsAttr(semantics::NO_SIL_VERIFICATION)) {
+    return;
+  }
+
   // If SILOwnership is not enabled, do not perform verification.
   if (!getModule().getOptions().VerifySILOwnership)
     return;
diff --git a/lib/SIL/Verifier/SILVerifier.cpp b/lib/SIL/Verifier/SILVerifier.cpp
index 655d00c0325dd..b32c4a4cc4003 100644
--- a/lib/SIL/Verifier/SILVerifier.cpp
+++ b/lib/SIL/Verifier/SILVerifier.cpp
@@ -35,6 +35,7 @@
 #include "swift/SIL/DebugUtils.h"
 #include "swift/SIL/Dominance.h"
 #include "swift/SIL/DynamicCasts.h"
+#include "swift/SIL/InstructionUtils.h"
 #include "swift/SIL/MemAccessUtils.h"
 #include "swift/SIL/OwnershipLiveness.h"
 #include "swift/SIL/OwnershipUtils.h"
@@ -572,6 +573,11 @@ void verifyKeyPathComponent(SILModule &M,
 /// open_existential_addr. We should expand it as needed.
 struct ImmutableAddressUseVerifier {
   SmallVector<Operand *, 32> worklist;
+  bool ignoreDestroys;
+  bool defaultIsMutating;
+
+  ImmutableAddressUseVerifier(bool ignoreDestroys = false, bool defaultIsMutating = false)
+    : ignoreDestroys(ignoreDestroys), defaultIsMutating(defaultIsMutating) {}
 
   bool isConsumingOrMutatingArgumentConvention(SILArgumentConvention conv) {
     switch (conv) {
@@ -704,10 +710,9 @@ struct ImmutableAddressUseVerifier {
           }
         }
 
-        // Otherwise this is a builtin that we are not expecting to see, so bail
-        // and assert.
-        llvm::errs() << "Unhandled, unexpected builtin instruction: " << *inst;
-        llvm_unreachable("invoking standard assertion failure");
+        // Otherwise this is a builtin that we are not expecting to see.
+        if (defaultIsMutating)
+          return true;
         break;
       }
       case SILInstructionKind::MarkDependenceInst:
@@ -775,7 +780,9 @@ struct ImmutableAddressUseVerifier {
         else
           break;
       case SILInstructionKind::DestroyAddrInst:
-        return true;
+        if (!ignoreDestroys)
+          return true;
+        break;
       case SILInstructionKind::UpcastInst:
       case SILInstructionKind::UncheckedAddrCastInst: {
         if (isAddrCastToNonConsuming(cast<SingleValueInstruction>(inst))) {
@@ -821,6 +828,7 @@ struct ImmutableAddressUseVerifier {
         LLVM_FALLTHROUGH;
       case SILInstructionKind::MoveOnlyWrapperToCopyableAddrInst:
       case SILInstructionKind::CopyableToMoveOnlyWrapperAddrInst:
+      case SILInstructionKind::VectorBaseAddrInst:
       case SILInstructionKind::StructElementAddrInst:
       case SILInstructionKind::TupleElementAddrInst:
       case SILInstructionKind::IndexAddrInst:
@@ -841,9 +849,7 @@ struct ImmutableAddressUseVerifier {
           }
           break;
         }
-        llvm::errs() << "Unhandled, unexpected instruction: " << *inst;
-        llvm_unreachable("invoking standard assertion failure");
-        break;
+        return true;
       }
       case SILInstructionKind::TuplePackElementAddrInst: {
         if (&cast<TuplePackElementAddrInst>(inst)->getOperandRef(
@@ -865,8 +871,8 @@ struct ImmutableAddressUseVerifier {
         return false;
       }
       default:
-        llvm::errs() << "Unhandled, unexpected instruction: " << *inst;
-        llvm_unreachable("invoking standard assertion failure");
+        if (defaultIsMutating)
+          return true;
         break;
       }
     }
@@ -1053,7 +1059,13 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
     
     auto objectTy = value->getType().unwrapOptionalType();
     
-    require(objectTy.isReferenceCounted(F.getModule()),
+    // Immortal C++ foreign reference types are represented as trivially lowered
+    // types since they do not require retain/release calls.
+    bool isImmortalFRT = objectTy.isForeignReferenceType() &&
+                         objectTy.getASTType()->getReferenceCounting() ==
+                             ReferenceCounting::None;
+
+    require(objectTy.isReferenceCounted(F.getModule()) || isImmortalFRT,
             valueDescription + " must have reference semantics");
   }
   
@@ -1223,7 +1235,7 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
 
     auto *DebugScope = F.getDebugScope();
     require(DebugScope, "All SIL functions must have a debug scope");
-    require(DebugScope->Parent.get<SILFunction *>() == &F,
+    require(cast<SILFunction *>(DebugScope->Parent) == &F,
             "Scope of SIL function points to different function");
   }
 
@@ -2381,7 +2393,8 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
     auto builtinKind = BI->getBuiltinKind();
     auto arguments = BI->getArguments();
 
-    if (builtinKind == BuiltinValueKind::ZeroInitializer) {
+    if (builtinKind == BuiltinValueKind::ZeroInitializer ||
+        builtinKind == BuiltinValueKind::PrepareInitialization) {
       require(!BI->getSubstitutions(),
               "zeroInitializer has no generic arguments as a SIL builtin");
       if (arguments.size() == 0) {
@@ -3128,47 +3141,6 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
             "initializer or setter has too many arguments");
   }
 
-  void checkAssignByWrapperInst(AssignByWrapperInst *AI) {
-    SILValue Src = AI->getSrc(), Dest = AI->getDest();
-    require(AI->getModule().getStage() == SILStage::Raw,
-            "assign instruction can only exist in raw SIL");
-    require(Dest->getType().isAddress(), "Must store to an address dest");
-
-    SILValue initFn = AI->getInitializer();
-    CanSILFunctionType initTy = initFn->getType().castTo<SILFunctionType>();
-    SILFunctionConventions initConv(initTy, AI->getModule());
-    checkAssignByWrapperArgs(Src->getType(), initConv);
-    switch (initConv.getNumIndirectSILResults()) {
-      case 0:
-        require(initConv.getNumDirectSILResults() == 1,
-                "wrong number of init function results");
-        requireSameType(
-            Dest->getType().getObjectType(),
-            *initConv.getDirectSILResultTypes(F.getTypeExpansionContext())
-                 .begin(),
-            "wrong init function result type");
-        break;
-      case 1:
-        require(initConv.getNumDirectSILResults() == 0,
-                "wrong number of init function results");
-        requireSameType(
-            Dest->getType(),
-            *initConv.getIndirectSILResultTypes(F.getTypeExpansionContext())
-                 .begin(),
-            "wrong indirect init function result type");
-        break;
-      default:
-        require(false, "wrong number of indirect init function results");
-    }
-
-    SILValue setterFn = AI->getSetter();
-    CanSILFunctionType setterTy = setterFn->getType().castTo<SILFunctionType>();
-    SILFunctionConventions setterConv(setterTy, AI->getModule());
-    require(setterConv.getNumIndirectSILResults() == 0,
-            "set function has indirect results");
-    checkAssignByWrapperArgs(Src->getType(), setterConv);
-  }
-
   void checkAssigOrInitInstAccessorArgs(SILType argTy,
                                         SILFunctionConventions &conv) {
     unsigned argIdx = conv.getSILArgIndexOfFirstParam();
@@ -4195,8 +4167,9 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
 
     auto lookupType = AMI->getLookupType();
     if (getLocalArchetypeOf(lookupType) || lookupType->hasDynamicSelfType()) {
-      require(AMI->getTypeDependentOperands().size() == 1,
-              "Must have a type dependent operand for the opened archetype");
+      require(!AMI->getTypeDependentOperands().empty(),
+              "Must have at least one type-dependent operand when there's a "
+              "local archetype or dynamic self.");
       verifyLocalArchetype(AMI, lookupType);
     } else {
       require(AMI->getTypeDependentOperands().empty() || lookupType->hasLocalArchetype(),
@@ -4270,16 +4243,19 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
     // If the method returns dynamic Self, substitute AnyObject for the
     // result type.
     if (auto fnDecl = dyn_cast<FuncDecl>(method.getDecl())) {
-      if (fnDecl->hasDynamicSelfResult()) {
+      if (fnDecl->getResultInterfaceType()->hasDynamicSelfType()) {
         auto anyObjectTy = C.getAnyObjectType();
         for (auto &result : results) {
-          auto newResultTy =
+          auto resultTy =
               result
                   .getReturnValueType(F.getModule(), methodTy,
-                                      F.getTypeExpansionContext())
-                  ->replaceCovariantResultType(anyObjectTy, 0);
-          result = SILResultInfo(newResultTy->getCanonicalType(),
-                                 result.getConvention());
+                                      F.getTypeExpansionContext());
+          if (resultTy->getOptionalObjectType())
+            resultTy = OptionalType::get(anyObjectTy)->getCanonicalType();
+          else
+            resultTy = anyObjectTy;
+
+          result = SILResultInfo(resultTy, result.getConvention());
         }
       }
     }
@@ -7369,7 +7345,7 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
 
     if (F->hasOwnership() && F->shouldVerifyOwnership() &&
         !mod.getASTContext().hadError()) {
-      F->verifyMemoryLifetime(calleeCache);
+      F->verifyMemoryLifetime(calleeCache, &getDeadEndBlocks());
     }
   }
 
@@ -7385,6 +7361,11 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
 #undef require
 #undef requireObjectType
 
+bool swift::isIndirectArgumentMutated(SILFunctionArgument *arg, bool ignoreDestroys,
+                                      bool defaultIsMutating) {
+  return ImmutableAddressUseVerifier(ignoreDestroys, defaultIsMutating).isMutatingOrConsuming(arg);
+}
+
 //===----------------------------------------------------------------------===//
 //                     Out of Line Verifier Run Functions
 //===----------------------------------------------------------------------===//
@@ -7419,6 +7400,10 @@ void SILFunction::verify(CalleeCache *calleeCache,
   if (!verificationEnabled(getModule()))
     return;
 
+  if (hasSemanticsAttr(semantics::NO_SIL_VERIFICATION)) {
+    return;
+  }
+
   // Please put all checks in visitSILFunction in SILVerifier, not here. This
   // ensures that the pretty stack trace in the verifier is included with the
   // back trace when the verifier crashes.
@@ -7648,57 +7633,111 @@ void SILVTable::verify(const SILModule &M) const {
 }
 
 /// Verify that a witness table follows invariants.
-void SILWitnessTable::verify(const SILModule &M) const {
-  if (!verificationEnabled(M))
+void SILWitnessTable::verify(const SILModule &mod) const {
+  if (!verificationEnabled(mod))
     return;
 
   if (isDeclaration())
     assert(getEntries().empty() &&
            "A witness table declaration should not have any entries.");
 
-  for (const Entry &E : getEntries())
-    if (E.getKind() == SILWitnessTable::WitnessKind::Method) {
-      SILFunction *F = E.getMethodWitness().Witness;
-      if (F) {
-        // If a SILWitnessTable is going to be serialized, it must only
-        // reference public or serializable functions.
-        if (isAnySerialized()) {
-          assert(F->hasValidLinkageForFragileRef(getSerializedKind()) &&
-                 "Fragile witness tables should not reference "
-                 "less visible functions.");
-        }
+  for (const Entry &entry : getEntries()) {
+    if (entry.getKind() != SILWitnessTable::WitnessKind::Method)
+      continue;
+
+    auto *witnessFunction = entry.getMethodWitness().Witness;
+    if (!witnessFunction)
+      continue;
 
-        assert(F->getLoweredFunctionType()->getRepresentation() ==
+    // If a SILWitnessTable is going to be serialized, it must only
+    // reference public or serializable functions.
+    if (isAnySerialized()) {
+      assert(
+          witnessFunction->hasValidLinkageForFragileRef(getSerializedKind()) &&
+          "Fragile witness tables should not reference "
+          "less visible functions.");
+    }
+
+    assert(witnessFunction->getLoweredFunctionType()->getRepresentation() ==
                SILFunctionTypeRepresentation::WitnessMethod &&
-               "Witnesses must have witness_method representation.");
+           "Witnesses must have witness_method representation.");
+
+    if (mod.getStage() != SILStage::Lowered &&
+        !mod.getASTContext().LangOpts.hasFeature(Feature::Embedded)) {
+      // Note the direction of the compatibility check: the witness
+      // function must be compatible with being used as the requirement
+      // type.
+      auto baseInfo = witnessFunction->getModule().Types.getConstantInfo(
+          TypeExpansionContext::minimal(),
+          entry.getMethodWitness().Requirement);
+      SmallString<32> baseName;
+      {
+        llvm::raw_svector_ostream os(baseName);
+        entry.getMethodWitness().Requirement.print(os);
       }
+
+      SILVerifier(*witnessFunction, /*calleeCache=*/nullptr,
+                  /*SingleFunction=*/true,
+                  /*checkLinearLifetime=*/false)
+          .requireABICompatibleFunctionTypes(
+              witnessFunction->getLoweredFunctionType(),
+              baseInfo.getSILType().castTo<SILFunctionType>(),
+              "witness table entry for " + baseName + " must be ABI-compatible",
+              *witnessFunction);
     }
+  }
 }
 
 /// Verify that a default witness table follows invariants.
-void SILDefaultWitnessTable::verify(const SILModule &M) const {
-#ifndef NDEBUG
-  for (const Entry &E : getEntries()) {
+void SILDefaultWitnessTable::verify(const SILModule &mod) const {
+  if (!verificationEnabled(mod))
+    return;
+
+  for (const Entry &entry : getEntries()) {
     // FIXME: associated type witnesses.
-    if (!E.isValid() || E.getKind() != SILWitnessTable::Method)
+    if (!entry.isValid() || entry.getKind() != SILWitnessTable::Method)
       continue;
 
-    SILFunction *F = E.getMethodWitness().Witness;
-    if (!F)
+    auto *witnessFunction = entry.getMethodWitness().Witness;
+    if (!witnessFunction)
       continue;
 
 #if 0
     // FIXME: For now, all default witnesses are private.
-    assert(F->hasValidLinkageForFragileRef(IsSerialized) &&
+    assert(witnessFunction->hasValidLinkageForFragileRef(IsSerialized) &&
            "Default witness tables should not reference "
            "less visible functions.");
 #endif
 
-    assert(F->getLoweredFunctionType()->getRepresentation() ==
-           SILFunctionTypeRepresentation::WitnessMethod &&
+    assert(witnessFunction->getLoweredFunctionType()->getRepresentation() ==
+               SILFunctionTypeRepresentation::WitnessMethod &&
            "Default witnesses must have witness_method representation.");
+
+    if (mod.getStage() != SILStage::Lowered &&
+        !mod.getASTContext().LangOpts.hasFeature(Feature::Embedded)) {
+      // Note the direction of the compatibility check: the witness
+      // function must be compatible with being used as the requirement
+      // type.
+      auto baseInfo = witnessFunction->getModule().Types.getConstantInfo(
+          TypeExpansionContext::minimal(),
+          entry.getMethodWitness().Requirement);
+      SmallString<32> baseName;
+      {
+        llvm::raw_svector_ostream os(baseName);
+        entry.getMethodWitness().Requirement.print(os);
+      }
+
+      SILVerifier(*witnessFunction, /*calleeCache=*/nullptr,
+                  /*SingleFunction=*/true,
+                  /*checkLinearLifetime=*/false)
+          .requireABICompatibleFunctionTypes(
+              witnessFunction->getLoweredFunctionType(),
+              baseInfo.getSILType().castTo<SILFunctionType>(),
+              "default witness table entry for " + baseName +
+                  " must be ABI-compatible",
+              *witnessFunction);
+    }
   }
-#endif
 }
 
 /// Verify that a global variable follows invariants.
@@ -7787,15 +7826,21 @@ void SILModule::verify(CalleeCache *calleeCache,
 
   // Check all witness tables.
   LLVM_DEBUG(llvm::dbgs() <<"*** Checking witness tables for duplicates ***\n");
-  llvm::DenseSet<ProtocolConformance*> wtableConformances;
+  llvm::DenseSet<llvm::PointerIntPair<ProtocolConformance *, 1, bool>> wtableConformances;
   for (const SILWitnessTable &wt : getWitnessTables()) {
     LLVM_DEBUG(llvm::dbgs() << "Witness Table:\n"; wt.dump());
     auto conformance = wt.getConformance();
-    if (!wtableConformances.insert(conformance).second) {
+    if (!wtableConformances.insert({conformance, wt.isSpecialized()}).second) {
       llvm::errs() << "Witness table redefined: ";
       conformance->printName(llvm::errs());
       assert(false && "triggering standard assertion failure routine");
     }
+    if (wt.isSpecialized()) {
+      ASSERT(specializedWitnessTableMap.find(conformance) != specializedWitnessTableMap.end());
+    } else {
+      auto *rootConf= cast<RootProtocolConformance>(conformance);
+      ASSERT(WitnessTableMap.find(rootConf) != WitnessTableMap.end());
+    }
     wt.verify(*this);
   }
 
diff --git a/lib/SILGen/CMakeLists.txt b/lib/SILGen/CMakeLists.txt
index c2c9e595f8065..71fc895654e6c 100644
--- a/lib/SILGen/CMakeLists.txt
+++ b/lib/SILGen/CMakeLists.txt
@@ -11,7 +11,7 @@ add_swift_host_library(swiftSILGen STATIC
   SwitchEnumBuilder.cpp
   SILGen.cpp
   SILGenApply.cpp
-  SILGenBackDeploy.cpp
+  SILGenAvailability.cpp
   SILGenBridging.cpp
   SILGenBuilder.cpp
   SILGenBuiltin.cpp
diff --git a/lib/SILGen/Cleanup.cpp b/lib/SILGen/Cleanup.cpp
index 4946ecb5dea0e..dc1bf5b44f160 100644
--- a/lib/SILGen/Cleanup.cpp
+++ b/lib/SILGen/Cleanup.cpp
@@ -167,19 +167,17 @@ void CleanupManager::emitBranchAndCleanups(JumpDest dest,
                                            SILLocation branchLoc,
                                            ArrayRef<SILValue> args,
                                            ForUnwind_t forUnwind) {
-  emitCleanupsForBranch(dest, branchLoc, args, forUnwind);
+  emitCleanupsBeforeBranch(dest, forUnwind);
   SGF.getBuilder().createBranch(branchLoc, dest.getBlock(), args);
 }
 
-/// emitBranchAndCleanups - Emit the cleanups necessary before branching to
+/// emitCleanupsBeforeBranch - Emit the cleanups necessary before branching to
 /// the given jump destination. This does not pop the cleanup stack, nor does
 /// it emit the actual branch.
-void CleanupManager::emitCleanupsForBranch(JumpDest dest,
-                                           SILLocation branchLoc,
-                                           ArrayRef<SILValue> args,
-                                           ForUnwind_t forUnwind) {
+void CleanupManager::emitCleanupsBeforeBranch(JumpDest dest,
+                                              ForUnwind_t forUnwind) {
   SILGenBuilder &builder = SGF.getBuilder();
-  assert(builder.hasValidInsertionPoint() && "Emitting branch in invalid spot");
+  assert(builder.hasValidInsertionPoint() && "no insertion point for cleanups");
   emitCleanups(dest.getDepth(), dest.getCleanupLocation(),
                forUnwind, /*popCleanups=*/false);
 }
diff --git a/lib/SILGen/Cleanup.h b/lib/SILGen/Cleanup.h
index 4dc96dd71e01c..6069eecaa3c94 100644
--- a/lib/SILGen/Cleanup.h
+++ b/lib/SILGen/Cleanup.h
@@ -74,6 +74,10 @@ enum class CleanupState {
   PersistentlyActive
 };
 
+inline bool isActiveCleanupState(CleanupState state) {
+  return state >= CleanupState::Active;
+}
+
 llvm::raw_ostream &operator<<(raw_ostream &os, CleanupState state);
 
 class LLVM_LIBRARY_VISIBILITY Cleanup {
@@ -109,7 +113,7 @@ class LLVM_LIBRARY_VISIBILITY Cleanup {
   virtual void setState(SILGenFunction &SGF, CleanupState newState) {
     state = newState;
   }
-  bool isActive() const { return state >= CleanupState::Active; }
+  bool isActive() const { return isActiveCleanupState(state); }
   bool isDead() const { return state == CleanupState::Dead; }
 
   virtual void emit(SILGenFunction &SGF, CleanupLocation loc,
@@ -222,15 +226,13 @@ class LLVM_LIBRARY_VISIBILITY CleanupManager {
                              ArrayRef<SILValue> args = {},
                              ForUnwind_t forUnwind = NotForUnwind);
 
-  /// Emit a branch to the given jump destination,
-  /// threading out through any cleanups we need to run. This does not pop the
-  /// cleanup stack.
+  /// Emit the cleanups necessary before branching to
+  /// the given jump destination. This does not pop the cleanup stack, nor does
+  /// it emit the actual branch.
   ///
   /// \param dest       The destination scope and block.
-  /// \param branchLoc  The location of the branch instruction.
-  /// \param args       Arguments to pass to the destination block.
-  void emitCleanupsForBranch(JumpDest dest, SILLocation branchLoc,
-                             ArrayRef<SILValue> args = {},
+  /// \param forUnwind  Whether the cleanups for this dest is for unwinding.
+  void emitCleanupsBeforeBranch(JumpDest dest,
                              ForUnwind_t forUnwind = NotForUnwind);
 
   /// emitCleanupsForReturn - Emit the top-level cleanups needed prior to a
diff --git a/lib/SILGen/Condition.cpp b/lib/SILGen/Condition.cpp
index c9701104156e8..eed3cde6cd049 100644
--- a/lib/SILGen/Condition.cpp
+++ b/lib/SILGen/Condition.cpp
@@ -100,7 +100,8 @@ void ConditionalValue::exitBranch(RValue &&condResult) {
     // already.
     assert(currentInitialization && "no current initialization?!");
     std::move(condResult).forwardInto(SGF, loc,
-                                      currentInitialization.release());
+                                      currentInitialization.get());
+    currentInitialization.reset();
     scope.reset();
     SGF.B.createBranch(loc, contBB);
   } else {
diff --git a/lib/SILGen/Condition.h b/lib/SILGen/Condition.h
index ba1b9222b830a..36b83b88013fb 100644
--- a/lib/SILGen/Condition.h
+++ b/lib/SILGen/Condition.h
@@ -109,7 +109,7 @@ class ConditionalValue {
   std::optional<Scope> scope;
 
   /// A place to hold conditional Initializations of our result.
-  std::unique_ptr<Initialization> currentInitialization;
+  InitializationPtr currentInitialization;
   
 public:
   /// Begins a conditional computation of the type represented by the given
diff --git a/lib/SILGen/Conversion.h b/lib/SILGen/Conversion.h
index 01fe4755a7d27..bd460ecb1b32c 100644
--- a/lib/SILGen/Conversion.h
+++ b/lib/SILGen/Conversion.h
@@ -17,10 +17,12 @@
 #ifndef SWIFT_LOWERING_CONVERSION_H
 #define SWIFT_LOWERING_CONVERSION_H
 
-#include "swift/Basic/Assertions.h"
-#include "swift/Basic/ExternalUnion.h"
 #include "Initialization.h"
 #include "SGFContext.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/Basic/ExternalUnion.h"
+#include "swift/SIL/AbstractionPattern.h"
+#include <optional>
 
 namespace swift {
 namespace Lowering {
@@ -115,6 +117,7 @@ class Conversion {
 
   struct BridgingStorage {
     bool IsExplicit;
+    AbstractionPattern InputOrigType;
   };
 
   /// The types we store for reabstracting contexts.  In general, when
@@ -161,11 +164,11 @@ class Conversion {
   static_assert(decltype(Types)::union_is_trivially_copyable,
                 "define the special members if this changes");
 
-  Conversion(KindTy kind, CanType sourceType, CanType resultType,
-             SILType loweredResultTy, bool isExplicit)
+  Conversion(KindTy kind, AbstractionPattern inputOrigType, CanType sourceType,
+             CanType resultType, SILType loweredResultTy, bool isExplicit)
       : Kind(kind), SourceType(sourceType), ResultType(resultType),
         LoweredResultType(loweredResultTy) {
-    Types.emplaceAggregate<BridgingStorage>(kind, isExplicit);
+    Types.emplaceAggregate<BridgingStorage>(kind, isExplicit, inputOrigType);
   }
 
   Conversion(AbstractionPattern inputOrigType, CanType inputSubstType,
@@ -236,13 +239,19 @@ class Conversion {
                       outputOrigType, outputSubstType, outputLoweredTy);
   }
 
-  static Conversion getBridging(KindTy kind, CanType origType,
-                                CanType resultType, SILType loweredResultTy,
-                                bool isExplicit = false) {
+  static Conversion
+  getBridging(KindTy kind, CanType origType, CanType resultType,
+              SILType loweredResultTy,
+              std::optional<AbstractionPattern> inputOrigType = std::nullopt,
+              bool isExplicit = false) {
     assert(isBridgingKind(kind));
     assert((kind != Subtype || isAllowedConversion(origType, resultType)) &&
            "disallowed conversion for subtype relationship");
-    return Conversion(kind, origType, resultType, loweredResultTy, isExplicit);
+    if (inputOrigType)
+      return Conversion(kind, *inputOrigType, origType, resultType,
+                        loweredResultTy, isExplicit);
+    return Conversion(kind, AbstractionPattern(origType), origType, resultType,
+                      loweredResultTy, isExplicit);
   }
 
   static Conversion getSubtype(CanType origType, CanType substType,
@@ -290,6 +299,10 @@ class Conversion {
     return Types.get<BridgingStorage>(Kind).IsExplicit;
   }
 
+  AbstractionPattern getBridgingOriginalInputType() const {
+    return Types.get<BridgingStorage>(Kind).InputOrigType;
+  }
+
   CanType getSourceType() const {
     return SourceType;
   }
diff --git a/lib/SILGen/FormalEvaluation.cpp b/lib/SILGen/FormalEvaluation.cpp
index 9087eb153a9d5..c929efed75293 100644
--- a/lib/SILGen/FormalEvaluation.cpp
+++ b/lib/SILGen/FormalEvaluation.cpp
@@ -195,6 +195,20 @@ void FormalEvaluationScope::verify() const {
   }
 }
 
+void FormalEvaluationScope::deferPop() && {
+  ASSERT(previous && "no previous scope to defer the pop for!");
+  auto &context = SGF.FormalEvalContext;
+
+  // Remove ourselves as the innermost scope of the chain.
+  ASSERT(context.innermostScope == this &&
+         "popping formal-evaluation scopes out of order");
+  context.innermostScope = previous;
+
+  // Clear-out our saved depth to deactivate our pop-on-deinit.
+  savedDepth.reset();
+}
+
+
 //===----------------------------------------------------------------------===//
 //                         Formal Evaluation Context
 //===----------------------------------------------------------------------===//
diff --git a/lib/SILGen/FormalEvaluation.h b/lib/SILGen/FormalEvaluation.h
index b69599b878414..38b0adc1a3ee3 100644
--- a/lib/SILGen/FormalEvaluation.h
+++ b/lib/SILGen/FormalEvaluation.h
@@ -224,6 +224,14 @@ class FormalEvaluationScope {
     savedDepth.reset();
   }
 
+  /// Defers the emission of clean-ups in this scope until the
+  /// immediate outer evaluation scope is popped.
+  ///
+  /// This is useful for getting-around tightly-nested formal
+  /// access scopes, when a borrow of a value needs to be
+  /// returned and copying the value is not an option.
+  void deferPop() &&;
+
   FormalEvaluationScope(const FormalEvaluationScope &) = delete;
   FormalEvaluationScope &operator=(const FormalEvaluationScope &) = delete;
 
diff --git a/lib/SILGen/Initialization.h b/lib/SILGen/Initialization.h
index f435353fb8c45..4cb4076eed247 100644
--- a/lib/SILGen/Initialization.h
+++ b/lib/SILGen/Initialization.h
@@ -19,6 +19,7 @@
 #define SWIFT_LOWERING_INITIALIZATION_H
 
 #include "ManagedValue.h"
+#include "swift/Basic/PossiblyUniquePtr.h"
 #include "swift/SIL/AbstractionPattern.h"
 #include "llvm/ADT/TinyPtrVector.h"
 #include <memory>
@@ -28,9 +29,9 @@ namespace Lowering {
 
 class SILGenFunction;
 class Initialization;
-using InitializationPtr = std::unique_ptr<Initialization>;
+using InitializationPtr = PossiblyUniquePtr<Initialization>;
 class TemporaryInitialization;
-using TemporaryInitializationPtr = std::unique_ptr<TemporaryInitialization>;
+using TemporaryInitializationPtr = PossiblyUniquePtr<TemporaryInitialization>;
 class ConvertingInitialization;
 
 /// An abstract class for consuming a value.  This is used for initializing
diff --git a/lib/SILGen/LValue.h b/lib/SILGen/LValue.h
index 3135f181920ec..432914fd8b14d 100644
--- a/lib/SILGen/LValue.h
+++ b/lib/SILGen/LValue.h
@@ -107,6 +107,7 @@ class PathComponent {
     ValueKind,                  // random base pointer as an lvalue
     PhysicalKeyPathApplicationKind, // applying a key path
     BorrowValueKind,            // load_borrow the base rvalue for a projection
+    BorrowMutateKind,           // borrow and mutate accessor
 
     // Logical LValue kinds
     GetterSetterKind,           // property or subscript getter/setter
diff --git a/lib/SILGen/ManagedValue.cpp b/lib/SILGen/ManagedValue.cpp
index f765b1b03cdb8..1256436cc0043 100644
--- a/lib/SILGen/ManagedValue.cpp
+++ b/lib/SILGen/ManagedValue.cpp
@@ -71,8 +71,8 @@ ManagedValue ManagedValue::copy(SILGenFunction &SGF, SILLocation loc) const {
 // WARNING: Callers of this API should manage the cleanup of this value!
 SILValue ManagedValue::unmanagedCopy(SILGenFunction &SGF,
                                          SILLocation loc) const {
-  auto &lowering = SGF.getTypeLowering(getType());
-  if (lowering.isTrivial())
+  auto props = SGF.getTypeProperties(getType());
+  if (props.isTrivial())
     return getValue();
 
   if (getType().isObject()) {
@@ -90,8 +90,8 @@ ManagedValue ManagedValue::formalAccessCopy(SILGenFunction &SGF,
                                             SILLocation loc) {
   assert(SGF.isInFormalEvaluationScope() &&
          "Can only perform a formal access copy in a formal evaluation scope");
-  auto &lowering = SGF.getTypeLowering(getType());
-  if (lowering.isTrivial())
+  auto props = SGF.getTypeProperties(getType());
+  if (props.isTrivial())
     return *this;
 
   if (getType().isObject()) {
@@ -219,8 +219,8 @@ ManagedValue ManagedValue::materialize(SILGenFunction &SGF,
     return ManagedValue::forOwnedAddressRValue(
         temporary, SGF.enterDestroyCleanup(temporary));
   }
-  auto &lowering = SGF.getTypeLowering(getType());
-  if (lowering.isAddressOnly()) {
+  auto props = SGF.getTypeProperties(getType());
+  if (props.isAddressOnly()) {
     assert(!SGF.silConv.useLoweredAddresses());
     auto copy = SGF.B.createCopyValue(loc, getValue());
     SGF.B.emitStoreValueOperation(loc, copy, temporary,
@@ -239,7 +239,7 @@ ManagedValue ManagedValue::formallyMaterialize(SILGenFunction &SGF,
                                                SILLocation loc) const {
   auto temporary = SGF.emitTemporaryAllocation(loc, getType());
   bool hadCleanup = hasCleanup();
-  auto &lowering = SGF.getTypeLowering(getType());
+  auto props = SGF.getTypeProperties(getType());
 
   if (hadCleanup) {
     SGF.B.emitStoreValueOperation(loc, forward(SGF), temporary,
@@ -248,7 +248,7 @@ ManagedValue ManagedValue::formallyMaterialize(SILGenFunction &SGF,
     return ManagedValue::forOwnedAddressRValue(
         temporary, SGF.enterDestroyCleanup(temporary));
   }
-  if (lowering.isAddressOnly()) {
+  if (props.isAddressOnly()) {
     assert(!SGF.silConv.useLoweredAddresses());
     auto copy = SGF.B.createCopyValue(loc, getValue());
     SGF.B.emitStoreValueOperation(loc, copy, temporary,
diff --git a/lib/SILGen/RValue.cpp b/lib/SILGen/RValue.cpp
index 254936ddf165d..16ad040354c0d 100644
--- a/lib/SILGen/RValue.cpp
+++ b/lib/SILGen/RValue.cpp
@@ -106,9 +106,9 @@ class ExplodeTupleValue
 
           auto eltTy = tuple.getType().getTupleElementType(index);
           assert(eltTy.isAddress() == tuple.getType().isAddress());
-          auto &eltTI = SGF.getTypeLowering(eltTy);
-          (void)eltTI;
-          assert(eltTI.isLoadable() || !SGF.silConv.useLoweredAddresses());
+          auto eltProps = SGF.getTypeProperties(eltTy);
+          (void)eltProps;
+          assert(eltProps.isLoadable() || !SGF.silConv.useLoweredAddresses());
 
           // Project the element.
           visit(eltFormalType, elt);
diff --git a/lib/SILGen/ResultPlan.cpp b/lib/SILGen/ResultPlan.cpp
index 770aa70bb58e9..fbcd3148e0b93 100644
--- a/lib/SILGen/ResultPlan.cpp
+++ b/lib/SILGen/ResultPlan.cpp
@@ -81,7 +81,7 @@ class IndirectOpenedSelfCleanup final : public Cleanup {
     assert(box && "buffer never emitted before activating cleanup?!");
     auto theBox = box;
     if (SGF.getASTContext().SILOpts.supportsLexicalLifetimes(SGF.getModule())) {
-      if (auto *bbi = cast<BeginBorrowInst>(theBox)) {
+      if (auto *bbi = dyn_cast<BeginBorrowInst>(theBox)) {
         SGF.B.createEndBorrow(loc, bbi);
         theBox = bbi->getOperand();
       }
@@ -225,14 +225,14 @@ class IndirectOpenedSelfResultPlan final : public ResultPlan {
 /// reabstracting it.  The value can actually be a tuple if the
 /// abstraction is opaque.
 class ScalarResultPlan final : public ResultPlan {
-  std::unique_ptr<TemporaryInitialization> temporary;
+  TemporaryInitializationPtr temporary;
   AbstractionPattern origType;
   CanType substType;
   Initialization *init;
   SILFunctionTypeRepresentation rep;
 
 public:
-  ScalarResultPlan(std::unique_ptr<TemporaryInitialization> &&temporary,
+  ScalarResultPlan(TemporaryInitializationPtr &&temporary,
                    AbstractionPattern origType, CanType substType,
                    Initialization *init,
                    SILFunctionTypeRepresentation rep)
@@ -339,13 +339,13 @@ class InitValueFromTemporaryResultPlan final : public ResultPlan {
   Initialization *init;
   CanType substType;
   ResultPlanPtr subPlan;
-  std::unique_ptr<TemporaryInitialization> temporary;
+  TemporaryInitializationPtr temporary;
 
 public:
   InitValueFromTemporaryResultPlan(
       Initialization *init, CanType substType,
       ResultPlanPtr &&subPlan,
-      std::unique_ptr<TemporaryInitialization> &&temporary)
+      TemporaryInitializationPtr &&temporary)
       : init(init), substType(substType), subPlan(std::move(subPlan)),
         temporary(std::move(temporary)) {}
 
@@ -792,10 +792,9 @@ class ForeignAsyncInitializationPlan final : public ResultPlan {
     return std::make_tuple(blockStorage, blockStorageTy, continuationTy);
   }
 
-  ManagedValue
-  emitForeignAsyncCompletionHandler(SILGenFunction &SGF,
-                                    AbstractionPattern origFormalType,
-                                    SILLocation loc) override {
+  ManagedValue emitForeignAsyncCompletionHandler(
+      SILGenFunction &SGF, AbstractionPattern origFormalType, ManagedValue self,
+      SILLocation loc) override {
     // Get the current continuation for the task.
     bool throws =
         calleeTypeInfo.foreign.async->completionHandlerErrorParamIndex()
@@ -845,7 +844,14 @@ class ForeignAsyncInitializationPlan final : public ResultPlan {
     SILValue block = SGF.B.createInitBlockStorageHeader(loc, blockStorage,
                           impRef, SILType::getPrimitiveObjectType(impFnTy),
                           SGF.getForwardingSubstitutionMap());
-    
+
+    // If our block is Sendable, we have lost the connection in between self and
+    // blockStorage. We need to restore that connection by using a merge
+    // isolation region.
+    if (self && block->getType().isSendable(&SGF.F)) {
+      SGF.B.createMergeIsolationRegion(loc, {self.getValue(), blockStorage});
+    }
+
     // Wrap it in optional if the callee expects it.
     if (handlerIsOptional) {
       block = SGF.B.createOptionalSome(loc, block, impTy);
@@ -1091,11 +1097,11 @@ class ForeignErrorInitializationPlan final : public ResultPlan {
     subPlan->gatherIndirectResultAddrs(SGF, loc, outList);
   }
 
-  ManagedValue
-  emitForeignAsyncCompletionHandler(SILGenFunction &SGF,
-                                    AbstractionPattern origFormalType,
-                                    SILLocation loc) override {
-    return subPlan->emitForeignAsyncCompletionHandler(SGF, origFormalType, loc);
+  ManagedValue emitForeignAsyncCompletionHandler(
+      SILGenFunction &SGF, AbstractionPattern origFormalType, ManagedValue self,
+      SILLocation loc) override {
+    return subPlan->emitForeignAsyncCompletionHandler(SGF, origFormalType, self,
+                                                      loc);
   }
 
   std::optional<std::pair<ManagedValue, ManagedValue>>
@@ -1243,7 +1249,7 @@ ResultPlanPtr ResultPlanBuilder::buildForScalar(Initialization *init,
   }
 
   // Create a temporary if the result is indirect.
-  std::unique_ptr<TemporaryInitialization> temporary;
+  TemporaryInitializationPtr temporary;
   if (SGF.silConv.isSILIndirect(result)) {
     auto &resultTL = SGF.getTypeLowering(result.getReturnValueType(
         SGF.SGM.M, calleeTy, SGF.getTypeExpansionContext()));
diff --git a/lib/SILGen/ResultPlan.h b/lib/SILGen/ResultPlan.h
index 0dde6e2801444..a667c874d7397 100644
--- a/lib/SILGen/ResultPlan.h
+++ b/lib/SILGen/ResultPlan.h
@@ -65,8 +65,10 @@ class ResultPlan {
     return std::nullopt;
   }
 
-  virtual ManagedValue emitForeignAsyncCompletionHandler(
-      SILGenFunction &SGF, AbstractionPattern origFormalType, SILLocation loc) {
+  virtual ManagedValue
+  emitForeignAsyncCompletionHandler(SILGenFunction &SGF,
+                                    AbstractionPattern origFormalType,
+                                    ManagedValue self, SILLocation loc) {
     return {};
   }
 };
diff --git a/lib/SILGen/SILGen.cpp b/lib/SILGen/SILGen.cpp
index cc4d3a1c5081a..a9aa7c7c5ecd1 100644
--- a/lib/SILGen/SILGen.cpp
+++ b/lib/SILGen/SILGen.cpp
@@ -51,6 +51,10 @@
 using namespace swift;
 using namespace Lowering;
 
+llvm::cl::list<std::string> PrintFunctionAST(
+    "print-function-ast", llvm::cl::CommaSeparated,
+    llvm::cl::desc("Only print out the ast for this function"));
+
 //===----------------------------------------------------------------------===//
 // SILGenModule Class implementation
 //===----------------------------------------------------------------------===//
@@ -458,6 +462,15 @@ FuncDecl *SILGenModule::getDeinitOnExecutor() {
   return lookupConcurrencyIntrinsic(getASTContext(), "_deinitOnExecutor");
 }
 
+FuncDecl *SILGenModule::getDeinitOnExecutorMainActorBackDeploy() {
+  auto found = lookupConcurrencyIntrinsic(getASTContext(),
+                                          "_deinitOnExecutorMainActorBackDeploy");
+  if (found)
+    return found;
+
+  return getDeinitOnExecutor();
+}
+
 FuncDecl *SILGenModule::getCreateExecutors() {
   return lookupConcurrencyIntrinsic(getASTContext(), "_createExecutors");
 }
@@ -514,25 +527,43 @@ FuncDecl *SILGenModule::getExit() {
 Type SILGenModule::getConfiguredExecutorFactory() {
   auto &ctx = getASTContext();
 
-  ModuleDecl *module;
-
-  // Parse the executor factory name
-  StringRef qualifiedName = *ctx.LangOpts.ExecutorFactory;
-  StringRef typeName;
+  // First look in the @main struct, if any
+  NominalTypeDecl *mainType = ctx.MainModule->getMainTypeDecl();
+  if (mainType) {
+    SmallVector<ValueDecl *, 1> decls;
+    auto identifier = ctx.getIdentifier("DefaultExecutorFactory");
+    mainType->lookupQualified(mainType,
+                              DeclNameRef(identifier),
+                              SourceLoc(),
+                              NL_RemoveNonVisible | NL_RemoveOverridden
+                              | NL_OnlyTypes | NL_ProtocolMembers,
+                              decls);
+    for (auto decl : decls) {
+      TypeDecl *typeDecl = dyn_cast<TypeDecl>(decl);
+      if (typeDecl) {
+        if (auto *nominalDecl = dyn_cast<NominalTypeDecl>(typeDecl)) {
+          return nominalDecl->getDeclaredType();
+        }
+
+        if (isa<AssociatedTypeDecl>(typeDecl)) {
+          // We ignore associatedtype declarations; those with a default will
+          // turn into a `typealias` instead.
+          continue;
+        }
+
+        return typeDecl->getDeclaredInterfaceType();
+      }
+    }
+  }
 
-  auto parts = qualifiedName.split('.');
+  // Failing that, look at the top level
+  Type factory = ctx.getNamedSwiftType(ctx.MainModule, "DefaultExecutorFactory");
 
-  if (parts.second.empty()) {
-    // This was an unqualified name; assume it's relative to the main module
-    module = ctx.MainModule;
-    typeName = qualifiedName;
-  } else {
-    Identifier moduleName = ctx.getIdentifier(parts.first);
-    module = ctx.getModuleByIdentifier(moduleName);
-    typeName = parts.second;
-  }
+  // If we don't find it, fall back to _Concurrency.PlatformExecutorFactory
+  if (!factory)
+    factory = getDefaultExecutorFactory();
 
-  return ctx.getNamedSwiftType(module, typeName);
+  return factory;
 }
 
 Type SILGenModule::getDefaultExecutorFactory() {
@@ -700,9 +731,11 @@ static bool shouldEmitFunctionBody(const AbstractFunctionDecl *AFD) {
     return false;
 
   auto &ctx = AFD->getASTContext();
-  if (ctx.TypeCheckerOpts.EnableLazyTypecheck) {
+  if (ctx.TypeCheckerOpts.EnableLazyTypecheck || AFD->isInMacroExpansionFromClangHeader()) {
     // Force the function body to be type-checked and then skip it if there
-    // have been any errors.
+    // have been any errors. Normally macro expansions are type checked in the module they
+    // expand in - this does not apply to swift macros applied to nodes imported from clang,
+    // so force type checking of them here if they haven't already, to prevent crashing.
     (void)AFD->getTypecheckedBody();
 
     // FIXME: Only skip bodies that contain type checking errors.
@@ -768,25 +801,6 @@ static bool isEmittedOnDemand(SILModule &M, SILDeclRef constant) {
   return false;
 }
 
-static ActorIsolation getActorIsolationForFunction(SILFunction &fn) {
-  if (auto constant = fn.getDeclRef()) {
-    if (constant.kind == SILDeclRef::Kind::Deallocator) {
-      // Deallocating destructor is always nonisolated. Isolation of the deinit
-      // applies only to isolated deallocator and destroyer.
-      return ActorIsolation::forNonisolated(false);
-    }
-
-    // If we have actor isolation for our constant, put the isolation onto the
-    // function. If the isolation is unspecified, we do not return it.
-    if (auto isolation =
-            getActorIsolationOfContext(constant.getInnermostDeclContext()))
-      return isolation;
-  }
-
-  // Otherwise, return for unspecified.
-  return ActorIsolation::forUnspecified();
-}
-
 SILFunction *SILGenModule::getFunction(SILDeclRef constant,
                                        ForDefinition_t forDefinition) {
   // If we already emitted the function, return it.
@@ -813,7 +827,7 @@ SILFunction *SILGenModule::getFunction(SILDeclRef constant,
       });
 
   F->setDeclRef(constant);
-  F->setActorIsolation(getActorIsolationForFunction(*F));
+  F->setActorIsolation(constant.getActorIsolation());
 
   assert(F && "SILFunction should have been defined");
 
@@ -881,6 +895,22 @@ void SILGenModule::visit(Decl *D) {
   ASTVisitor::visit(D);
 }
 
+static bool isInPrintFunctionList(AbstractFunctionDecl *fd) {
+  if (PrintFunctionAST.empty()) {
+    return false;
+  }
+  auto fnName = SILDeclRef(fd).mangle();
+  for (const std::string &printFnName : PrintFunctionAST) {
+    if (printFnName == fnName)
+      return true;
+    if (!printFnName.empty() && printFnName[0] != '$' && !fnName.empty() &&
+        fnName[0] == '$' && printFnName == fnName.substr(1)) {
+      return true;
+    }
+  }
+  return false;
+}
+
 void SILGenModule::visitFuncDecl(FuncDecl *fd) { emitFunction(fd); }
 
 void SILGenModule::emitFunctionDefinition(SILDeclRef constant, SILFunction *f) {
@@ -1115,6 +1145,25 @@ void SILGenModule::emitFunctionDefinition(SILDeclRef constant, SILFunction *f) {
     break;
   }
 
+  case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor: {
+    auto *var = cast<VarDecl>(constant.getDecl());
+    auto loc = RegularLocation::getAutoGeneratedLocation(var);
+
+    preEmitFunction(constant, f, loc);
+    PrettyStackTraceSILFunction X("silgen propertyWrappedFieldInitAccessor", f);
+    f->createProfiler(constant);
+
+    auto *init = constant.getInitializationExpr();
+    assert(init);
+
+    auto varDC = var->getInnermostDeclContext();
+    SILGenFunction SGF(*this, *f, varDC);
+    SGF.emitPropertyWrappedFieldInitAccessor(constant, init,
+                                             /*EmitProfilerIncrement*/ true);
+    postEmitFunction(constant, f);
+    break;
+  }
+
   case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue: {
     auto *var = cast<VarDecl>(constant.getDecl());
 
@@ -1309,7 +1358,25 @@ void SILGenModule::preEmitFunction(SILDeclRef constant, SILFunction *F,
   F->setDeclRef(constant);
 
   // Set our actor isolation.
-  F->setActorIsolation(getActorIsolationForFunction(*F));
+  F->setActorIsolation(constant.getActorIsolation());
+
+  // Closures automatically infer [manual_ownership] based on outermost func.
+  //
+  // We need to add this constraint _prior_ to emitting the closure's body,
+  // because the output from SILGen slightly differs because of this constraint
+  // when it comes to the CopyExpr and SILMoveOnlyWrappedType usage.
+  //
+  // If ManualOwnership ends up subsuming those prior mechanisms for an
+  // explicit-copy mode, we can move this somewhere else, like postEmitFunction.
+  if (auto *ace = constant.getAbstractClosureExpr()) {
+    if (auto *dc = ace->getOutermostFunctionContext()) {
+      if (auto *decl = dc->getAsDecl()) {
+        if (decl->getAttrs().hasAttribute<ManualOwnershipAttr>()) {
+          F->setPerfConstraints(PerformanceConstraints::ManualOwnership);
+        }
+      }
+    }
+  }
 
   LLVM_DEBUG(llvm::dbgs() << "lowering ";
              F->printName(llvm::dbgs());
@@ -1437,14 +1504,19 @@ void SILGenModule::emitDifferentiabilityWitness(
   auto *diffWitness = M.lookUpDifferentiabilityWitness(key);
   if (!diffWitness) {
     // Differentiability witnesses have the same linkage as the original
-    // function, stripping external.
-    auto linkage = stripExternalFromLinkage(originalFunction->getLinkage());
+    // function, stripping external. For @_alwaysEmitIntoClient original
+    // functions, force PublicNonABI linkage of the differentiability witness so
+    // we can serialize it (the original function itself might be HiddenExternal
+    // in this case if we only have declaration without definition).
+    auto linkage =
+        originalFunction->markedAsAlwaysEmitIntoClient()
+            ? SILLinkage::PublicNonABI
+            : stripExternalFromLinkage(originalFunction->getLinkage());
     diffWitness = SILDifferentiabilityWitness::createDefinition(
         M, linkage, originalFunction, diffKind, silConfig.parameterIndices,
         silConfig.resultIndices, config.derivativeGenericSignature,
         /*jvp*/ nullptr, /*vjp*/ nullptr,
-        /*isSerialized*/ hasPublicVisibility(originalFunction->getLinkage()),
-        attr);
+        /*isSerialized*/ hasPublicVisibility(linkage), attr);
   }
 
   // Set derivative function in differentiability witness.
@@ -1474,6 +1546,11 @@ void SILGenModule::emitDifferentiabilityWitness(
 }
 
 void SILGenModule::emitAbstractFuncDecl(AbstractFunctionDecl *AFD) {
+  if (isInPrintFunctionList(AFD)) {
+    auto &out = llvm::errs();
+    AFD->dump(out);
+  }
+  
   // Emit default arguments and property wrapper initializers.
   emitArgumentGenerators(AFD, AFD->getParameters());
 
@@ -1490,7 +1567,7 @@ void SILGenModule::emitAbstractFuncDecl(AbstractFunctionDecl *AFD) {
 
   emitDistributedThunkForDecl(AFD);
 
-  if (AFD->isBackDeployed(M.getASTContext())) {
+  if (AFD->isBackDeployed()) {
     // Emit the fallback function that will be used when the original function
     // is unavailable at runtime.
     auto fallback = SILDeclRef(AFD).asBackDeploymentKind(
@@ -1608,10 +1685,10 @@ bool SILGenModule::hasNonTrivialIVars(ClassDecl *cd) {
     auto *vd = dyn_cast<VarDecl>(member);
     if (!vd || !vd->hasStorage()) continue;
 
-    auto &ti = Types.getTypeLowering(
+    auto props = Types.getTypeProperties(
         vd->getTypeInContext(),
         TypeExpansionContext::maximalResilienceExpansionOnly());
-    if (!ti.isTrivial())
+    if (!props.isTrivial())
       return true;
   }
 
@@ -1635,7 +1712,7 @@ void SILGenModule::emitObjCAllocatorDestructor(ClassDecl *cd,
   // Emit the isolated deallocating destructor.
   // If emitted, it implements actual deallocating and deallocating destructor
   // only switches executor
-  if (dd->hasBody() && isActorIsolated) {
+  if (dd->hasBody() && !dd->isBodySkipped() && isActorIsolated) {
     SILDeclRef dealloc(dd, SILDeclRef::Kind::IsolatedDeallocator);
     emitFunctionDefinition(dealloc, getFunction(dealloc, ForDefinition));
   }
@@ -1811,6 +1888,11 @@ emitPropertyWrapperBackingInitializer(VarDecl *var) {
   }
 }
 
+void SILGenModule::emitPropertyWrappedFieldInitAccessor(VarDecl *var) {
+  SILDeclRef constant(var, SILDeclRef::Kind::PropertyWrappedFieldInitAccessor);
+  emitOrDelayFunction(constant);
+}
+
 SILFunction *SILGenModule::emitLazyGlobalInitializer(StringRef funcName,
                                                  PatternBindingDecl *binding,
                                                      unsigned pbdEntry) {
@@ -1974,7 +2056,7 @@ SILGenModule::canStorageUseStoredKeyPathComponent(AbstractStorageDecl *decl,
   auto strategy = decl->getAccessStrategy(
       AccessSemantics::Ordinary,
       decl->supportsMutation() ? AccessKind::ReadWrite : AccessKind::Read,
-      M.getSwiftModule(), expansion,
+      M.getSwiftModule(), expansion, std::nullopt,
       /*useOldABI=*/false);
   switch (strategy.getKind()) {
   case AccessStrategy::Storage: {
@@ -2072,17 +2154,16 @@ void SILGenModule::tryEmitPropertyDescriptor(AbstractStorageDecl *decl) {
   if (!SILModuleConventions(M).useLoweredAddresses())
     return;
   
-  if (!decl->exportsPropertyDescriptor())
+  auto descriptorContext = decl->getPropertyDescriptorGenericSignature();
+  if (!descriptorContext)
     return;
 
   PrettyStackTraceDecl stackTrace("emitting property descriptor for", decl);
 
   Type baseTy;
   if (decl->getDeclContext()->isTypeContext()) {
-
     baseTy = decl->getDeclContext()->getSelfInterfaceType()
-                 ->getReducedType(decl->getInnermostDeclContext()
-                                      ->getGenericSignatureOfContext());
+                 ->getReducedType(*descriptorContext);
     
     if (decl->isStatic()) {
       baseTy = MetatypeType::get(baseTy);
@@ -2093,8 +2174,7 @@ void SILGenModule::tryEmitPropertyDescriptor(AbstractStorageDecl *decl) {
     llvm_unreachable("should not export a property descriptor yet");
   }
 
-  auto genericEnv = decl->getInnermostDeclContext()
-                        ->getGenericEnvironmentOfContext();
+  auto genericEnv = descriptorContext->getGenericEnvironment();
   unsigned baseOperand = 0;
   bool needsGenericContext = true;
   
@@ -2104,8 +2184,16 @@ void SILGenModule::tryEmitPropertyDescriptor(AbstractStorageDecl *decl) {
   }
   
   SubstitutionMap subs;
-  if (genericEnv)
-    subs = genericEnv->getForwardingSubstitutionMap();
+  if (genericEnv) {
+    // The substitutions are used when invoking the underlying accessors, so
+    // we get these from the original declaration generic environment, even if
+    // `getPropertyDescriptorGenericSignature` computed a different generic
+    // environment, since the accessors will not need the extra Copyable or
+    // Escapable requirements.
+    subs = SubstitutionMap::get(decl->getInnermostDeclContext()
+                                    ->getGenericSignatureOfContext(),
+      genericEnv->getForwardingSubstitutionMap());
+  }
   
   auto component = emitKeyPathComponentForDecl(SILLocation(decl),
                                                genericEnv,
diff --git a/lib/SILGen/SILGen.h b/lib/SILGen/SILGen.h
index 3cefec2015209..78261cf646ed5 100644
--- a/lib/SILGen/SILGen.h
+++ b/lib/SILGen/SILGen.h
@@ -84,6 +84,9 @@ class LLVM_LIBRARY_VISIBILITY SILGenModule : public ASTVisitor<SILGenModule> {
   /// Set of delayed conformances that have already been forced.
   llvm::DenseSet<NormalProtocolConformance *> forcedConformances;
 
+  /// Imported noncopyable types that we have seen.
+  llvm::DenseSet<NominalTypeDecl *> importedNontrivialNoncopyableTypes;
+
   size_t anonymousSymbolCounter = 0;
 
   std::optional<SILDeclRef> StringToNSStringFn;
@@ -266,6 +269,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenModule : public ASTVisitor<SILGenModule> {
   void visitDestructorDecl(DestructorDecl *d) {}
   void visitModuleDecl(ModuleDecl *d) { }
   void visitMissingMemberDecl(MissingMemberDecl *d) {}
+  void visitUsingDecl(UsingDecl *) {}
 
   // Emitted as part of its storage.
   void visitAccessorDecl(AccessorDecl *ad) {}
@@ -281,6 +285,8 @@ class LLVM_LIBRARY_VISIBILITY SILGenModule : public ASTVisitor<SILGenModule> {
   void visitMacroDecl(MacroDecl *d);
   void visitMacroExpansionDecl(MacroExpansionDecl *d);
 
+  void visitImportedNontrivialNoncopyableType(NominalTypeDecl *nominal);
+
   // Same as AbstractStorageDecl::visitEmittedAccessors, but skips over skipped
   // (unavailable) decls.
   void visitEmittedAccessors(AbstractStorageDecl *D,
@@ -334,6 +340,10 @@ class LLVM_LIBRARY_VISIBILITY SILGenModule : public ASTVisitor<SILGenModule> {
   /// Emits the backing initializer for a property with an attached wrapper.
   void emitPropertyWrapperBackingInitializer(VarDecl *var);
 
+  /// Emits an init accessor that contains a call to the backing storage
+  /// initializer for a property with an attached property wrapper
+  void emitPropertyWrappedFieldInitAccessor(VarDecl *var);
+
   /// Emits argument generators, including default argument generators and
   /// property wrapper argument generators, for the given parameter list.
   void emitArgumentGenerators(SILDeclRef::Loc decl, ParameterList *paramList);
@@ -556,6 +566,8 @@ class LLVM_LIBRARY_VISIBILITY SILGenModule : public ASTVisitor<SILGenModule> {
   FuncDecl *getSwiftJobRun();
   /// Retrieve the _Concurrency._deinitOnExecutor intrinsic.
   FuncDecl *getDeinitOnExecutor();
+  /// Retrieve the _Concurrency._deinitOnExecutorMainActorBackDeploy intrinsic.
+  FuncDecl *getDeinitOnExecutorMainActorBackDeploy();
   // Retrieve the _SwiftConcurrencyShims.exit intrinsic.
   FuncDecl *getExit();
 
diff --git a/lib/SILGen/SILGenApply.cpp b/lib/SILGen/SILGenApply.cpp
index 620f7497f120f..8f7b88ba8f3c2 100644
--- a/lib/SILGen/SILGenApply.cpp
+++ b/lib/SILGen/SILGenApply.cpp
@@ -22,6 +22,7 @@
 #include "ResultPlan.h"
 #include "Scope.h"
 #include "SpecializedEmitter.h"
+#include "StorageRefResult.h"
 #include "Varargs.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ConformanceLookup.h"
@@ -62,7 +63,7 @@ FunctionTypeInfo SILGenFunction::getClosureTypeInfo(AbstractClosureExpr *expr) {
   auto fnType = cast<AnyFunctionType>(expr->getType()->getCanonicalType());
 
   // If we have a closure expr that has inherits actor context, work around AST
-  // issues that causes us to be able to get non-Sendable actor isolated
+  // issues that causes us to be able to get non-Sendable actor-isolated
   // closures.
   if (auto *ce = dyn_cast<ClosureExpr>(expr)) {
     if (ce->inheritsActorContext() && fnType->isAsync() &&
@@ -95,7 +96,6 @@ SubstitutionMap SILGenModule::mapSubstitutionsForWitnessOverride(
   Type origProtoSelfType = origProto->getSelfInterfaceType();
   auto baseProto = cast<ProtocolDecl>(overridden->getDeclContext());
   return SubstitutionMap::getProtocolSubstitutions(
-      baseProto, origProtoSelfType.subst(subs),
       subs.lookupConformance(origProtoSelfType->getCanonicalType(), baseProto));
 }
 
@@ -149,10 +149,10 @@ getPartialApplyOfDynamicMethodFormalType(SILGenModule &SGM, SILDeclRef member,
 
   // Adjust the result type to replace dynamic-self with AnyObject.
   CanType resultType = completeMethodTy.getResult();
-  if (auto fnDecl = dyn_cast<FuncDecl>(member.getDecl())) {
-    if (fnDecl->hasDynamicSelfResult()) {
+  if (isa<FuncDecl>(member.getDecl())) {
+    if (resultType->hasDynamicSelfType()) {
       auto anyObjectTy = SGM.getASTContext().getAnyObjectType();
-      resultType = resultType->replaceCovariantResultType(anyObjectTy, 0)
+      resultType = resultType->replaceDynamicSelfType(anyObjectTy)
                              ->getCanonicalType();
     }
   }
@@ -453,7 +453,7 @@ class Callee {
     auto &ci = SGF.getConstantInfo(SGF.getTypeExpansionContext(), c);
     return Callee(
         SGF, c, ci.FormalPattern, ci.FormalType,
-        subs.mapIntoTypeExpansionContext(SGF.getTypeExpansionContext()),
+        substOpaqueTypesWithUnderlyingTypes(subs, SGF.getTypeExpansionContext()),
         subs,
         l,
         callPreviousDynamicReplaceableImpl);
@@ -466,7 +466,7 @@ class Callee {
     auto &ci = SGF.getConstantInfo(SGF.getTypeExpansionContext(), c);
     return Callee(
         Kind::EnumElement, SGF, c, ci.FormalPattern, ci.FormalType,
-        subs.mapIntoTypeExpansionContext(SGF.getTypeExpansionContext()), l);
+        substOpaqueTypesWithUnderlyingTypes(subs, SGF.getTypeExpansionContext()), l);
   }
   static Callee forClassMethod(SILGenFunction &SGF,
                                SILDeclRef c, SubstitutionMap subs,
@@ -474,7 +474,7 @@ class Callee {
     auto base = c.getOverriddenVTableEntry();
     auto &baseCI = SGF.getConstantInfo(SGF.getTypeExpansionContext(), base);
     auto &derivedCI = SGF.getConstantInfo(SGF.getTypeExpansionContext(), c);
-    subs = subs.mapIntoTypeExpansionContext(SGF.getTypeExpansionContext());
+    subs = substOpaqueTypesWithUnderlyingTypes(subs, SGF.getTypeExpansionContext());
 
     // We use an orig function type based on the overridden vtable entry, but
     // the substitutions we have are for the current function.  To get subs
@@ -498,7 +498,7 @@ class Callee {
                                SILDeclRef c, SubstitutionMap subs,
                                SILLocation l) {
     auto &ci = SGF.getConstantInfo(SGF.getTypeExpansionContext(), c);
-    subs = subs.mapIntoTypeExpansionContext(SGF.getTypeExpansionContext());
+    subs = substOpaqueTypesWithUnderlyingTypes(subs, SGF.getTypeExpansionContext());
     auto origFunctionType = ci.FormalPattern.withSubstitutions(subs);
     return Callee(
         Kind::SuperMethod, SGF, c, origFunctionType, ci.FormalType, subs, l);
@@ -524,8 +524,9 @@ class Callee {
 
     auto &ci = SGF.getConstantInfo(SGF.getTypeExpansionContext(), c);
     return Callee(
-        Kind::WitnessMethod, SGF, c, ci.FormalPattern, ci.FormalType,
-        subs.mapIntoTypeExpansionContext(SGF.getTypeExpansionContext()), l);
+        Kind::WitnessMethod, SGF, c,
+        ci.FormalPattern.withSubstitutions(subs), ci.FormalType,
+        substOpaqueTypesWithUnderlyingTypes(subs, SGF.getTypeExpansionContext()), l);
   }
   static Callee forDynamic(SILGenFunction &SGF,
                            SILDeclRef c, SubstitutionMap constantSubs,
@@ -551,7 +552,7 @@ class Callee {
 
     return Callee(
         Kind::DynamicMethod, SGF, c, origFormalType, substFormalType,
-        subs.mapIntoTypeExpansionContext(SGF.getTypeExpansionContext()), l);
+        substOpaqueTypesWithUnderlyingTypes(subs, SGF.getTypeExpansionContext()), l);
   }
 
   static Callee formCallee(SILGenFunction &SGF, AbstractFunctionDecl *decl,
@@ -1718,6 +1719,37 @@ class SILGenApply : public Lowering::ExprVisitor<SILGenApply> {
     return false;
   }
 
+  static bool addsNonIsolatedNonSendingToAsyncFn(FunctionConversionExpr *fce) {
+    CanType oldTy = fce->getSubExpr()->getType()->getCanonicalType();
+    CanType newTy = fce->getType()->getCanonicalType();
+
+    if (auto oldFnTy = dyn_cast<AnyFunctionType>(oldTy)) {
+      if (auto newFnTy = dyn_cast<AnyFunctionType>(newTy)) {
+        // old type and new type MUST both be async
+        if (!oldFnTy->hasEffect(EffectKind::Async) ||
+            !newFnTy->hasEffect(EffectKind::Async))
+          return false;
+
+        // old type MUST NOT have nonisolated(nonsending).
+        if (oldFnTy->getIsolation().isNonIsolatedCaller())
+          return false;
+
+        // new type MUST nonisolated(nonsending)
+        if (!newFnTy->getIsolation().isNonIsolatedCaller())
+          return false;
+
+        // See if setting isolation of old type to nonisolated(nonsending)
+        // yields the new type.
+        auto addedNonIsolatedNonSending = oldFnTy->getExtInfo().withIsolation(
+            FunctionTypeIsolation::forNonIsolatedCaller());
+
+        return oldFnTy->withExtInfo(addedNonIsolatedNonSending) == newFnTy;
+      }
+    }
+
+    return false;
+  }
+
   /// Ignore parentheses and implicit conversions.
   static Expr *ignoreParensAndImpConversions(Expr *expr) {
     while (true) {
@@ -1738,6 +1770,8 @@ class SILGenApply : public Lowering::ExprVisitor<SILGenApply> {
           if (auto funcConv = dyn_cast<FunctionConversionExpr>(nextSubExpr)) {
             if (addsGlobalActorToAsyncFn(funcConv))
               nextSubExpr = funcConv->getSubExpr();
+            else if (addsNonIsolatedNonSendingToAsyncFn(funcConv))
+              nextSubExpr = funcConv->getSubExpr();
           }
 
           if (auto bind = dyn_cast<BindOptionalExpr>(nextSubExpr)) {
@@ -1775,7 +1809,7 @@ class SILGenApply : public Lowering::ExprVisitor<SILGenApply> {
 
     auto openExistential = dyn_cast<OpenExistentialExpr>(arg);
     if (openExistential)
-      arg = openExistential->getSubExpr();
+      arg = ignoreParensAndImpConversions(openExistential->getSubExpr());
 
     auto dynamicMemberRef = dyn_cast<DynamicMemberRefExpr>(arg);
     if (!dynamicMemberRef)
@@ -1934,15 +1968,21 @@ static void emitRawApply(SILGenFunction &SGF,
   SmallVector<SILValue, 4> argValues;
 
   // Add the buffers for the indirect results if needed.
-#ifndef NDEBUG
-  assert(indirectResultAddrs.size() == substFnConv.getNumIndirectSILResults());
   unsigned resultIdx = 0;
-  for (auto indResultTy :
-       substFnConv.getIndirectSILResultTypes(SGF.getTypeExpansionContext())) {
-    assert(indResultTy == indirectResultAddrs[resultIdx++]->getType());
+  for (auto indResultTy : substFnConv.getIndirectSILResultTypes(SGF.getTypeExpansionContext())) {
+    auto indResultAddr = indirectResultAddrs[resultIdx++];
+
+    if (indResultAddr->getType() != indResultTy) {
+      // Bitcast away differences in Sendable, global actor, etc.
+      if (indResultAddr->getType().stripConcurrency(/*recursive*/ true, /*dropGlobalActor*/ true)
+          == indResultTy.stripConcurrency(/*recursive*/ true, /*dropGlobalActor*/ true)) {
+        indResultAddr = SGF.B.createUncheckedAddrCast(loc, indResultAddr, indResultTy);
+      }
+    }
+    assert(indResultTy == indResultAddr->getType());
+
+    argValues.push_back(indResultAddr);
   }
-#endif
-  argValues.append(indirectResultAddrs.begin(), indirectResultAddrs.end());
 
   assert(!!indirectErrorAddr == substFnConv.hasIndirectSILErrorResults());
   if (indirectErrorAddr)
@@ -2049,10 +2089,17 @@ static void emitRawApply(SILGenFunction &SGF,
     auto result = normalBB->createPhiArgument(resultType, OwnershipKind::Owned);
     rawResults.push_back(result);
 
+    // If the error is not passed indirectly, include the expected error type
+    // according to the SILFunctionConvention.
+    std::optional<TaggedUnion<SILValue, SILType>> errorAddrOrType;
+    if (indirectErrorAddr)
+        errorAddrOrType = indirectErrorAddr;
+    else
+      errorAddrOrType = substFnConv.getSILErrorType(SGF.getTypeExpansionContext());
+
     SILBasicBlock *errorBB =
       SGF.getTryApplyErrorDest(loc, substFnType, prevExecutor,
-                               substFnType->getErrorResult(),
-                               indirectErrorAddr,
+                                *errorAddrOrType,
                                options.contains(ApplyFlags::DoesNotThrow));
 
     options -= ApplyFlags::DoesNotThrow;
@@ -3040,6 +3087,11 @@ static void emitDelayedArguments(SILGenFunction &SGF,
   // up in parallel, with empty spots being dropped into 'args'
   // wherever there's a delayed argument to insert.
   //
+  // Note that siteArgs has exactly one empty element for each
+  // delayed argument, even if the argument actually expands to
+  // zero or multiple SIL values. In such cases, we may have to
+  // remove or add elements to fill in the actual argument values.
+  //
   // Note that this also begins the formal accesses in evaluation order.
   for (auto argsIt = args.begin(); argsIt != args.end(); ++argsIt) {
     auto &siteArgs = *argsIt;
@@ -3047,6 +3099,10 @@ static void emitDelayedArguments(SILGenFunction &SGF,
     for (size_t i = 0; i < siteArgs.size(); ) {
       auto &siteArg = siteArgs[i];
       
+      // Skip slots in the argument array that we've already filled in.
+      // Note that this takes advantage of the "exactly one element"
+      // assumption above, since default arguments might have () type
+      // and therefore expand to no actual argument slots.
       if (siteArg) {
         ++i;
         continue;
@@ -3057,6 +3113,7 @@ static void emitDelayedArguments(SILGenFunction &SGF,
 
       if (defaultArgIsolation && delayedArg.isDefaultArg()) {
         isolatedArgs.push_back(std::make_tuple(delayedNext, argsIt, i));
+        ++i;
         if (++delayedNext == delayedArgs.end()) {
           goto done;
         } else {
@@ -3127,14 +3184,44 @@ static void emitDelayedArguments(SILGenFunction &SGF,
       SGF.emitHopToTargetExecutor(loc, executor);
     }
 
-    size_t argsEmitted = 0;
+    // The index saved in isolatedArgs is the index where we're
+    // supposed to fill in the argument in siteArgs. It should point
+    // to a single null element, which we will replace with zero or
+    // more actual argument values. This replacement can invalidate
+    // later indices, so we need to apply an adjustment as we go.
+    //
+    // That adjustment only applies within the right siteArgs and
+    // must be reset when we change siteArgs. Fortunately, emission
+    // is always left-to-right and never revisits a siteArgs.
+    size_t indexAdjustment = 0;
+    auto indexAdjustmentSite = args.begin();
+
     for (auto &isolatedArg : isolatedArgs) {
       auto &delayedArg = *std::get<0>(isolatedArg);
-      auto &siteArgs = *std::get<1>(isolatedArg);
-      auto argIndex = std::get<2>(isolatedArg) + argsEmitted;
-      auto origIndex = argIndex;
+      auto site = std::get<1>(isolatedArg);
+      auto &siteArgs = *site;
+      size_t argIndex = std::get<2>(isolatedArg);
+
+      // Apply the current index adjustment if we haven't changed
+      // sites.
+      if (indexAdjustmentSite == site) {
+        argIndex += indexAdjustment;
+
+      // Otherwise, reset the current index adjustment.
+      } else {
+        indexAdjustment = 0;
+      }
+
+      assert(!siteArgs[argIndex] &&
+             "overwriting an existing arg during delayed isolated "
+             "argument emission");
+
+      size_t origIndex = argIndex;
       delayedArg.emit(SGF, siteArgs, argIndex);
-      argsEmitted += (argIndex - origIndex);
+
+      // Accumulate the adjustment. Note that the adjustment can
+      // be negative, and we end up relying on modular unsigned math.
+      indexAdjustment += (argIndex - origIndex - 1);
     }
   }
 
@@ -3155,105 +3242,6 @@ static void emitDelayedArguments(SILGenFunction &SGF,
   }
 }
 
-namespace {
-/// Container to hold the result of a search for the storage reference
-/// when determining to emit a borrow.
-struct StorageRefResult {
-private:
-  Expr *storageRef;
-  Expr *transitiveRoot;
-
-public:
-  // Represents an empty result
-  StorageRefResult() : storageRef(nullptr), transitiveRoot(nullptr) {}
-  bool isEmpty() const { return transitiveRoot == nullptr; }
-  operator bool() const { return !isEmpty(); }
-
-  /// The root of the expression that accesses the storage in \c storageRef.
-  /// When in doubt, this is probably what you want, as it includes the
-  /// entire expression tree involving the reference.
-  Expr *getTransitiveRoot() const { return transitiveRoot; }
-
-  /// The direct storage reference that was discovered.
-  Expr *getStorageRef() const { return storageRef; }
-
-  StorageRefResult(Expr *storageRef, Expr *transitiveRoot)
-      : storageRef(storageRef), transitiveRoot(transitiveRoot) {
-    assert(storageRef && transitiveRoot && "use the zero-arg init for empty");
-  }
-
-  // Initializes a storage reference where the base matches the ref.
-  StorageRefResult(Expr *storageRef)
-      : StorageRefResult(storageRef, storageRef) {}
-
-  StorageRefResult withTransitiveRoot(StorageRefResult refResult) const {
-    return withTransitiveRoot(refResult.transitiveRoot);
-  }
-
-  StorageRefResult withTransitiveRoot(Expr *newRoot) const {
-    return StorageRefResult(storageRef, newRoot);
-  }
-};
-} // namespace
-
-static StorageRefResult findStorageReferenceExprForBorrow(Expr *e) {
-  e = e->getSemanticsProvidingExpr();
-
-  // These are basically defined as the cases implemented by SILGenLValue.
-
-  // Direct storage references.
-  if (auto dre = dyn_cast<DeclRefExpr>(e)) {
-    if (isa<VarDecl>(dre->getDecl()))
-      return dre;
-  } else if (auto mre = dyn_cast<MemberRefExpr>(e)) {
-    if (isa<VarDecl>(mre->getDecl().getDecl()))
-      return mre;
-  } else if (isa<SubscriptExpr>(e)) {
-    return e;
-  } else if (isa<OpaqueValueExpr>(e)) {
-    return e;
-  } else if (isa<KeyPathApplicationExpr>(e)) {
-    return e;
-
-  // Transitive storage references.  Look through these to see if the
-  // sub-expression is a storage reference, but don't return the
-  // sub-expression.
-  } else if (auto tue = dyn_cast<TupleElementExpr>(e)) {
-    if (auto result = findStorageReferenceExprForBorrow(tue->getBase()))
-      return result.withTransitiveRoot(tue);
-
-  } else if (auto fve = dyn_cast<ForceValueExpr>(e)) {
-    if (auto result = findStorageReferenceExprForBorrow(fve->getSubExpr()))
-      return result.withTransitiveRoot(fve);
-
-  } else if (auto boe = dyn_cast<BindOptionalExpr>(e)) {
-    if (auto result = findStorageReferenceExprForBorrow(boe->getSubExpr()))
-      return result.withTransitiveRoot(boe);
-
-  } else if (auto oe = dyn_cast<OpenExistentialExpr>(e)) {
-    if (findStorageReferenceExprForBorrow(oe->getExistentialValue()))
-      if (auto result = findStorageReferenceExprForBorrow(oe->getSubExpr()))
-        return result.withTransitiveRoot(oe);
-
-  } else if (auto bie = dyn_cast<DotSyntaxBaseIgnoredExpr>(e)) {
-    if (auto result = findStorageReferenceExprForBorrow(bie->getRHS()))
-      return result.withTransitiveRoot(bie);
-
-  } else if (auto te = dyn_cast<AnyTryExpr>(e)) {
-    if (auto result = findStorageReferenceExprForBorrow(te->getSubExpr()))
-      return result.withTransitiveRoot(te);
-
-  } else if (auto ioe = dyn_cast<InOutExpr>(e)) {
-    if (auto result = findStorageReferenceExprForBorrow(ioe->getSubExpr()))
-      return result.withTransitiveRoot(ioe);
-  } else if (auto le = dyn_cast<LoadExpr>(e)) {
-    if (auto result = findStorageReferenceExprForBorrow(le->getSubExpr()))
-      return result.withTransitiveRoot(le);
-  }
-
-  return StorageRefResult();
-}
-
 Expr *SILGenFunction::findStorageReferenceExprForMoveOnly(Expr *argExpr,
                                            StorageReferenceOperationKind kind) {
   ForceValueExpr *forceUnwrap = nullptr;
@@ -3308,7 +3296,7 @@ Expr *SILGenFunction::findStorageReferenceExprForMoveOnly(Expr *argExpr,
     }
   }
 
-  auto result = ::findStorageReferenceExprForBorrow(argExpr);
+  auto result = StorageRefResult::findStorageReferenceExprForBorrow(argExpr);
 
   if (!result)
     return nullptr;
@@ -3335,12 +3323,15 @@ Expr *SILGenFunction::findStorageReferenceExprForMoveOnly(Expr *argExpr,
 
   if (!storage)
     return nullptr;
+
   // This should match the strategy computation used in
   // SILGenLValue::visit{DeclRef,Member}RefExpr.
-  auto strategy = storage->getAccessStrategy(accessSemantics,
-         AccessKind::Read, SGM.M.getSwiftModule(), F.getResilienceExpansion(),
-         /* old abi*/ false);
-  
+  auto strategy = storage->getAccessStrategy(
+      accessSemantics, AccessKind::Read, SGM.M.getSwiftModule(),
+      F.getResilienceExpansion(),
+      std::make_pair<>(argExpr->getSourceRange(), FunctionDC),
+      /* old abi*/ false);
+
   switch (strategy.getKind()) {
   case AccessStrategy::Storage:
     // Storage can benefit from direct borrowing/consumption.
@@ -3356,6 +3347,8 @@ Expr *SILGenFunction::findStorageReferenceExprForMoveOnly(Expr *argExpr,
     case AccessorKind::Read2:
     case AccessorKind::Modify:
     case AccessorKind::Modify2:
+    case AccessorKind::Borrow:
+    case AccessorKind::Mutate:
       // Accessors that produce a borrow/inout value can be borrowed.
       break;
     
@@ -3428,8 +3421,9 @@ SILGenFunction::findStorageReferenceExprForBorrowExpr(Expr *argExpr) {
   if (!borrowExpr)
     return nullptr;
 
-  return ::findStorageReferenceExprForBorrow(borrowExpr->getSubExpr())
-                     .getTransitiveRoot();
+  return StorageRefResult::findStorageReferenceExprForBorrow(
+             borrowExpr->getSubExpr())
+      .getTransitiveRoot();
 }
 
 Expr *
@@ -3450,8 +3444,8 @@ Expr *ArgumentSource::findStorageReferenceExprForBorrow() && {
   if (!isExpr()) return nullptr;
 
   auto argExpr = asKnownExpr();
-  auto *lvExpr =
-      ::findStorageReferenceExprForBorrow(argExpr).getTransitiveRoot();
+  auto *lvExpr = StorageRefResult::findStorageReferenceExprForBorrow(argExpr)
+                     .getTransitiveRoot();
 
   // Claim the value of this argument if we found a storage reference.
   if (lvExpr) {
@@ -3464,27 +3458,201 @@ Expr *ArgumentSource::findStorageReferenceExprForBorrow() && {
 ManagedValue
 SILGenFunction::tryEmitAddressableParameterAsAddress(ArgumentSource &&arg,
                                                      ValueOwnership ownership) {
+  if (!arg.isExpr()) {
+    return ManagedValue();
+  }
+
   // If the function takes an addressable parameter, and its argument is
   // a reference to an addressable declaration with compatible ownership,
   // forward the address along in-place.
-  if (arg.isExpr()) {
-    auto origExpr = std::move(arg).asKnownExpr();
-    auto expr = origExpr;
+  auto origExpr = std::move(arg).asKnownExpr();
+  auto expr = origExpr;
+  
+  // If the expression does not have a stable address to return, then restore
+  // the ArgumentSource and return a null value to the caller.
+  auto notAddressable = [&] {
+    arg = ArgumentSource(origExpr);
+    return ManagedValue();
+  };
+  
+  if (auto le = dyn_cast<LoadExpr>(expr)) {
+    expr = le->getSubExpr();
+  }
+  if (auto dre = dyn_cast<DeclRefExpr>(expr)) {
+    if (auto param = dyn_cast<VarDecl>(dre->getDecl())) {
+      if (auto addr = getVariableAddressableBuffer(param, expr,
+                                                   ownership)) {
+        return ManagedValue::forBorrowedAddressRValue(addr);
+      }
+    }
+  }
+  
+  // Property or subscript member accesses may also be addressable.
+  
+  AccessKind accessKind;
+  switch (ownership) {
+  case ValueOwnership::Shared:
+  case ValueOwnership::Default:
+    accessKind = AccessKind::Read;
+    break;
+  case ValueOwnership::Owned:
+  case ValueOwnership::InOut:
+    accessKind = AccessKind::ReadWrite;
+    break;
+  }
+
+  LookupExpr *lookupExpr;
+  AbstractStorageDecl *memberStorage;
+  SubstitutionMap subs;
+  AccessSemantics accessSemantics;
+  PreparedArguments indices;
+
+  if (auto mre = dyn_cast<MemberRefExpr>(expr)) {
+    lookupExpr = mre;
+    memberStorage = dyn_cast<VarDecl>(mre->getMember().getDecl());
+    subs = mre->getMember().getSubstitutions();
+    accessSemantics = mre->getAccessSemantics();
+  } else if (auto se = dyn_cast<SubscriptExpr>(expr)) {
+    lookupExpr = se;
+    auto subscriptDecl = cast<SubscriptDecl>(se->getMember().getDecl());
+    memberStorage = subscriptDecl;
+    subs = se->getMember().getSubstitutions();
+    accessSemantics = se->getAccessSemantics();
     
-    if (auto le = dyn_cast<LoadExpr>(expr)) {
-      expr = le->getSubExpr();
-    }
-    if (auto dre = dyn_cast<DeclRefExpr>(expr)) {
-      if (auto param = dyn_cast<VarDecl>(dre->getDecl())) {
-        if (auto addr = getLocalVariableAddressableBuffer(param, expr,
-                                                          ownership)) {
-          return ManagedValue::forBorrowedAddressRValue(addr);
-        }
+    indices = PreparedArguments(
+      subscriptDecl->getInterfaceType()->castTo<AnyFunctionType>()
+                   ->getParams(),
+      se->getArgs());
+  } else {
+    return notAddressable();
+  }
+  
+  if (!memberStorage) {
+    return notAddressable();
+  }
+  
+  auto strategy = memberStorage->getAccessStrategy(accessSemantics, accessKind,
+    SGM.M.getSwiftModule(), F.getResilienceExpansion(),
+    std::make_pair<>(expr->getSourceRange(), FunctionDC),
+    /*old abi (doesn't matter here)*/ false);
+
+  switch (strategy.getKind()) {
+  case AccessStrategy::Storage: {
+    auto vd = cast<VarDecl>(memberStorage);
+    // TODO: Is it possible and/or useful for class storage to be
+    // addressable?
+    if (!vd->isInstanceMember()
+        || !isa<StructDecl>(vd->getDeclContext())) {
+      return notAddressable();
+    }
+  
+    // If the storage holds the fully-abstracted representation of the
+    // type, then we can use its address.
+    auto absBaseTy = getLoweredType(AbstractionPattern::getOpaque(),
+                 lookupExpr->getBase()->getType()->getWithoutSpecifierType());
+    auto memberTy = absBaseTy.getFieldType(vd, &F);
+    auto absMemberTy = getLoweredType(AbstractionPattern::getOpaque(),
+                            lookupExpr->getType()->getWithoutSpecifierType());
+    
+    if (memberTy.getAddressType() != absMemberTy.getAddressType()) {
+      // The storage is not fully abstracted, so it can't serve as a
+      // stable address.
+      return notAddressable();
+    }
+    
+    // Otherwise, we can project the field address from the stable address
+    // of the base, if it has one. Try to get the stable address for the
+    // base.
+    auto baseAddr = tryEmitAddressableParameterAsAddress(
+      ArgumentSource(lookupExpr->getBase()), ownership);
+      
+    if (!baseAddr) {
+      return notAddressable();
+    }
+    
+    // Project the field's address.
+    auto fieldAddr = B.createStructElementAddr(lookupExpr,
+                                               baseAddr.getValue(), vd);
+    return ManagedValue::forBorrowedAddressRValue(fieldAddr);
+  }
+  
+  case AccessStrategy::DirectToAccessor:
+  case AccessStrategy::DispatchToAccessor: {
+    // Non-addressor accessors don't produce stable addresses.
+    if (strategy.getAccessor() != AccessorKind::Address
+        && strategy.getAccessor() != AccessorKind::MutableAddress) {
+      return notAddressable();
+    }
+    // TODO: Non-yielding borrow/mutate accessors can also be considered
+    // addressable when we have those.
+    
+    auto addressor = memberStorage->getAccessor(strategy.getAccessor());
+    auto addressorRef = SILDeclRef(addressor, SILDeclRef::Kind::Func);
+    auto absMemberTy = getLoweredType(AbstractionPattern::getOpaque(),
+                               lookupExpr->getType()->getWithoutSpecifierType())
+      .getAddressType();
+
+    // Evaluate the base in the current formal access scope.
+    ManagedValue base;
+    // If the addressor wants the base addressable, try to honor that
+    // request.
+    auto addressorSelf = addressor->getImplicitSelfDecl();
+    if (addressorSelf->isAddressable()
+        || getTypeProperties(lookupExpr->getBase()->getType()
+                                       ->getWithoutSpecifierType())
+            .isAddressableForDependencies()) {
+      ValueOwnership baseOwnership = addressorSelf->isInOut()
+        ? ValueOwnership::InOut
+        : ValueOwnership::Shared;
+      
+      base = tryEmitAddressableParameterAsAddress(
+        ArgumentSource(lookupExpr->getBase()), baseOwnership);
+    }
+    
+    // Otherwise, project the base as an lvalue.
+    if (!base) {
+      SGFAccessKind silAccess;
+      switch (accessKind) {
+      case AccessKind::Read:
+        silAccess = SGFAccessKind::BorrowedAddressRead;
+        break;
+      case AccessKind::ReadWrite:
+      case AccessKind::Write:
+        silAccess = SGFAccessKind::ReadWrite;
+        break;
       }
+      
+      LValue lv = emitLValue(lookupExpr, silAccess);
+      
+      drillToLastComponent(lookupExpr->getBase(), std::move(lv), base);
     }
-    arg = ArgumentSource(origExpr);
+    
+    // Materialize the base outside of the scope of the addressor call,
+    // since the returned address may depend on the materialized
+    // representation, even if it isn't transitively addressable.
+    auto baseTy = lookupExpr->getBase()
+                      ->getType()
+                      ->getWithoutSpecifierType()
+                      ->getCanonicalType();
+    ArgumentSource baseArg = prepareAccessorBaseArgForFormalAccess(
+      lookupExpr->getBase(), base, baseTy, addressorRef);
+    
+    // Invoke the addressor to directly produce the address.
+    return emitAddressorAccessor(lookupExpr,
+       addressorRef, subs,
+       std::move(baseArg),
+       /*super*/ false, /*direct accessor use*/ true,
+       std::move(indices),
+       absMemberTy, /*on self*/ false);
+  }
+  
+  case AccessStrategy::MaterializeToTemporary:
+  case AccessStrategy::DispatchToDistributedThunk:
+    // These strategies never produce a value with a stable address.
+    return notAddressable();
   }
-  return ManagedValue();
+  
+  llvm_unreachable("uncovered switch!");
 }
 
 namespace {
@@ -3579,9 +3747,9 @@ class ArgEmitter {
             }
             
             if (scoped->contains(i)) {
-              addressable = SGF.getTypeLowering(origFormalParamType,
-                                                origFormalParamType.getType())
-                .getRecursiveProperties().isAddressableForDependencies();
+              addressable = SGF.getTypeProperties(origFormalParamType,
+                                                  origFormalParamType.getType())
+                .isAddressableForDependencies();
             }
           }
         }
@@ -4003,10 +4171,10 @@ class ArgEmitter {
                                             loweredSubstArgType,
                                             param.getSILStorageInterfaceType());
         case SILFunctionLanguage::C:
-          return Conversion::getBridging(Conversion::BridgeToObjC,
-             arg.getSubstRValueType(),
-             origParamType.getType(),
-             param.getSILStorageInterfaceType());
+          return Conversion::getBridging(
+              Conversion::BridgeToObjC, arg.getSubstRValueType(),
+              origParamType.getType(), param.getSILStorageInterfaceType(),
+              origParamType);
         }
         llvm_unreachable("bad language");
       }();
@@ -5000,6 +5168,7 @@ class CallEmission {
   FormalEvaluationScope initialWritebackScope;
   std::optional<ActorIsolation> implicitActorHopTarget;
   bool implicitlyThrows;
+  bool canUnwind;
 
 public:
   /// Create an emission for a call of the given callee.
@@ -5007,7 +5176,8 @@ class CallEmission {
                FormalEvaluationScope &&writebackScope)
       : SGF(SGF), callee(std::move(callee)),
         initialWritebackScope(std::move(writebackScope)),
-        implicitActorHopTarget(std::nullopt), implicitlyThrows(false) {}
+        implicitActorHopTarget(std::nullopt), implicitlyThrows(false),
+        canUnwind(false) {}
 
   /// A factory method for decomposing the apply expr \p e into a call
   /// emission.
@@ -5058,8 +5228,12 @@ class CallEmission {
   /// function can throw or not.
   void setImplicitlyThrows(bool flag) { implicitlyThrows = flag; }
 
+  void setCanUnwind(bool flag) { canUnwind = flag; }
+
   CleanupHandle applyCoroutine(SmallVectorImpl<ManagedValue> &yields);
 
+  ManagedValue applyBorrowMutateAccessor();
+
   RValue apply(SGFContext C = SGFContext()) {
     initialWritebackScope.verify();
 
@@ -5115,9 +5289,11 @@ namespace {
 /// Cleanup to end a coroutine application.
 class EndCoroutineApply : public Cleanup {
   SILValue ApplyToken;
+  bool CanUnwind;
   std::vector<BeginBorrowInst *> BorrowedMoveOnlyValues;
 public:
-  EndCoroutineApply(SILValue applyToken) : ApplyToken(applyToken) {}
+  EndCoroutineApply(SILValue applyToken, bool CanUnwind)
+      : ApplyToken(applyToken), CanUnwind(CanUnwind) {}
 
   void setBorrowedMoveOnlyValues(ArrayRef<BeginBorrowInst *> values) {
     BorrowedMoveOnlyValues.insert(BorrowedMoveOnlyValues.end(),
@@ -5130,14 +5306,7 @@ class EndCoroutineApply : public Cleanup {
       SGF.B.createEndBorrow(l, *i);
       SGF.B.createDestroyValue(l, (*i)->getOperand());
     }
-    auto *beginApply =
-        cast<BeginApplyInst>(ApplyToken->getDefiningInstruction());
-    auto isCalleeAllocated = beginApply->isCalleeAllocated();
-    auto unwindOnCallerError =
-        !isCalleeAllocated ||
-        SGF.SGM.getASTContext().LangOpts.hasFeature(
-            Feature::CoroutineAccessorsUnwindOnCallerError);
-    if (forUnwind && unwindOnCallerError) {
+    if (forUnwind && CanUnwind) {
       SGF.B.createAbortApply(l, ApplyToken);
     } else {
       SGF.B.createEndApply(l, ApplyToken,
@@ -5180,18 +5349,15 @@ CallEmission::applyCoroutine(SmallVectorImpl<ManagedValue> &yields) {
 
   auto fnValue = callee.getFnValue(SGF, borrowedSelf);
 
-  return SGF.emitBeginApply(uncurriedLoc.value(), fnValue,
+  return SGF.emitBeginApply(uncurriedLoc.value(), fnValue, canUnwind,
                             callee.getSubstitutions(), uncurriedArgs,
                             calleeTypeInfo.substFnType, options, yields);
 }
 
-CleanupHandle
-SILGenFunction::emitBeginApply(SILLocation loc, ManagedValue fn,
-                               SubstitutionMap subs,
-                               ArrayRef<ManagedValue> args,
-                               CanSILFunctionType substFnType,
-                               ApplyOptions options,
-                               SmallVectorImpl<ManagedValue> &yields) {
+CleanupHandle SILGenFunction::emitBeginApply(
+    SILLocation loc, ManagedValue fn, bool canUnwind, SubstitutionMap subs,
+    ArrayRef<ManagedValue> args, CanSILFunctionType substFnType,
+    ApplyOptions options, SmallVectorImpl<ManagedValue> &yields) {
   // Emit the call.
   SmallVector<SILValue, 4> rawResults;
   emitRawApply(*this, loc, fn, subs, args, substFnType, options,
@@ -5207,7 +5373,7 @@ SILGenFunction::emitBeginApply(SILLocation loc, ManagedValue fn,
 
   // Push a cleanup to end the application.
   // TODO: destroy all the arguments at exactly this point?
-  Cleanups.pushCleanup<EndCoroutineApply>(token);
+  Cleanups.pushCleanup<EndCoroutineApply>(token, canUnwind);
   auto endApplyHandle = getTopCleanup();
 
   // Manage all the yielded values.
@@ -5267,6 +5433,75 @@ SILGenFunction::emitBeginApply(SILLocation loc, ManagedValue fn,
   return endApplyHandle;
 }
 
+ManagedValue CallEmission::applyBorrowMutateAccessor() {
+  auto origFormalType = callee.getOrigFormalType();
+  // Get the callee type information.
+  auto calleeTypeInfo = callee.getTypeInfo(SGF);
+
+  std::optional<ManagedValue> self;
+  auto fnValue = callee.getFnValue(SGF, self);
+
+  // Evaluate the arguments.
+  SmallVector<ManagedValue, 4> uncurriedArgs;
+  std::optional<SILLocation> uncurriedLoc;
+  ApplyOptions options = emitArgumentsForNormalApply(
+      origFormalType, calleeTypeInfo.substFnType,
+      origFormalType.getLifetimeDependencies(), calleeTypeInfo.foreign,
+      uncurriedArgs, uncurriedLoc);
+
+  auto selfArgMV = uncurriedArgs.back();
+
+  // Strip the unnecessary copy_value + mark_unresolved_non_copyable_value +
+  // begin_borrow instructions added for move-only self argument.
+  if (selfArgMV.getValue()->getType().isMoveOnly() &&
+      selfArgMV.getValue()->getType().isObject()) {
+    uncurriedArgs[uncurriedArgs.size() - 1] =
+        ManagedValue::forBorrowedObjectRValue(
+            lookThroughMoveOnlyCheckerPattern(selfArgMV.getValue()));
+  }
+
+  auto value = SGF.applyBorrowMutateAccessor(
+      uncurriedLoc.value(), fnValue, canUnwind, callee.getSubstitutions(),
+      uncurriedArgs, calleeTypeInfo.substFnType, options);
+
+  return value;
+}
+
+ManagedValue SILGenFunction::applyBorrowMutateAccessor(
+    SILLocation loc, ManagedValue fn, bool canUnwind, SubstitutionMap subs,
+    ArrayRef<ManagedValue> args, CanSILFunctionType substFnType,
+    ApplyOptions options) {
+  // Emit the call.
+  SmallVector<SILValue, 4> rawResults;
+  emitRawApply(*this, loc, fn, subs, args, substFnType, options,
+               /*indirect results*/ {}, /*indirect errors*/ {}, rawResults,
+               ExecutorBreadcrumb());
+  assert(rawResults.size() == 1);
+  auto rawResult = rawResults[0];
+
+  if (fn.getFunction()->getConventions().hasGuaranteedResult()) {
+    auto selfArg = args.back().getValue();
+    if (isa<LoadBorrowInst>(selfArg)) {
+      rawResult = emitUncheckedGuaranteedConversion(rawResult);
+    }
+  }
+  if (rawResult->getType().isMoveOnly()) {
+    if (rawResult->getType().isAddress()) {
+      auto result = B.createMarkUnresolvedNonCopyableValueInst(
+          loc, rawResult,
+          MarkUnresolvedNonCopyableValueInst::CheckKind::NoConsumeOrAssign);
+      return ManagedValue::forRValueWithoutOwnership(result);
+    }
+    auto result = emitManagedCopy(loc, rawResult);
+    result = B.createMarkUnresolvedNonCopyableValueInst(
+        loc, result,
+        MarkUnresolvedNonCopyableValueInst::CheckKind::NoConsumeOrAssign);
+    return emitManagedBeginBorrow(loc, result.getValue());
+  }
+
+  return ManagedValue::forForwardedRValue(*this, rawResult);
+}
+
 RValue CallEmission::applyFirstLevelCallee(SGFContext C) {
   // Check for a specialized emitter.
   if (auto emitter = callee.getSpecializedEmitter(SGF.SGM)) {
@@ -5606,8 +5841,7 @@ ApplyOptions CallEmission::emitArgumentsForNormalApply(
   // Now, actually handle the implicit parameters.
   if (auto isolated = substFnType->maybeGetIsolatedParameter();
       isolated && isolated->hasOption(SILParameterInfo::ImplicitLeading)) {
-    auto executor =
-        ManagedValue::forBorrowedObjectRValue(SGF.ExpectedExecutor.getEager());
+    auto executor = SGF.emitExpectedExecutor(callSite->Loc);
     args.push_back({});
     // NOTE: Even though this calls emitActorInstanceIsolation, this also
     // handles glboal actor isolated cases.
@@ -5762,9 +5996,9 @@ RValue SILGenFunction::emitApply(
 
   SILValue indirectErrorAddr;
   if (substFnType->hasErrorResult()) {
-    auto errorResult = substFnType->getErrorResult();
-    if (errorResult.getConvention() == ResultConvention::Indirect) {
-      auto loweredErrorResultType = getSILType(errorResult, substFnType);
+    auto convention = silConv.getFunctionConventions(substFnType);
+    if (auto errorResult = convention.getIndirectErrorResult()) {
+      auto loweredErrorResultType = getSILType(*errorResult, substFnType);
       indirectErrorAddr = B.createAllocStack(loc, loweredErrorResultType);
       enterDeallocStackCleanup(indirectErrorAddr);
     }
@@ -5820,9 +6054,16 @@ RValue SILGenFunction::emitApply(
     // we left during the first pass.
     auto &completionArgSlot = const_cast<ManagedValue &>(args[completionIndex]);
 
+    // We have already lowered foreign self/moved it into position at this
+    // point, so we know that self will be back.
+    ManagedValue self;
+    if (substFnType->hasSelfParam()) {
+      self = args.back();
+    }
+
     auto origFormalType = *calleeTypeInfo.origFormalType;
     completionArgSlot = resultPlan->emitForeignAsyncCompletionHandler(
-        *this, origFormalType, loc);
+        *this, origFormalType, self, loc);
   }
   if (auto foreignError = calleeTypeInfo.foreign.error) {
     unsigned errorParamIndex =
@@ -5873,13 +6114,15 @@ RValue SILGenFunction::emitApply(
     SILValue executor;
     switch (*implicitActorHopTarget) {
     case ActorIsolation::ActorInstance:
-      if (unsigned paramIndex =
-              implicitActorHopTarget->getActorInstanceParameter()) {
+      assert(!implicitActorHopTarget->isActorInstanceForCapture());
+      if (implicitActorHopTarget->isActorInstanceForSelfParameter()) {
+        executor = emitLoadActorExecutor(loc, args.back());
+      } else {
+        unsigned paramIndex =
+          implicitActorHopTarget->getActorInstanceParameterIndex();
         auto isolatedIndex = calleeTypeInfo.origFormalType
-          ->getLoweredParamIndex(paramIndex - 1);
+          ->getLoweredParamIndex(paramIndex);
         executor = emitLoadActorExecutor(loc, args[isolatedIndex]);
-      } else {
-        executor = emitLoadActorExecutor(loc, args.back());
       }
       break;
 
@@ -5979,11 +6222,15 @@ RValue SILGenFunction::emitApply(
                                  B.getDefaultAtomicity());
         hasAlreadyLifetimeExtendedSelf = true;
       }
-      LLVM_FALLTHROUGH;
+      result = resultTL.emitCopyValue(B, loc, result);
+      break;
 
     case ResultConvention::Unowned:
-      // Unretained. Retain the value.
-      result = resultTL.emitCopyValue(B, loc, result);
+      // Handled in OwnershipModelEliminator.
+      break;
+    case ResultConvention::GuaranteedAddress:
+    case ResultConvention::Guaranteed:
+      llvm_unreachable("borrow accessor is not yet implemented");
       break;
     }
 
@@ -6184,7 +6431,7 @@ SILValue SILGenFunction::emitApplyWithRethrow(SILLocation loc, SILValue fn,
 std::tuple<MultipleValueInstructionResult *, CleanupHandle, SILValue,
            CleanupHandle>
 SILGenFunction::emitBeginApplyWithRethrow(SILLocation loc, SILValue fn,
-                                          SILType substFnType,
+                                          SILType substFnType, bool canUnwind,
                                           SubstitutionMap subs,
                                           ArrayRef<SILValue> args,
                                           SmallVectorImpl<SILValue> &yields) {
@@ -6209,7 +6456,7 @@ SILGenFunction::emitBeginApplyWithRethrow(SILLocation loc, SILValue fn,
     deallocCleanup = enterDeallocStackCleanup(allocation);
   }
 
-  Cleanups.pushCleanup<EndCoroutineApply>(token);
+  Cleanups.pushCleanup<EndCoroutineApply>(token, canUnwind);
   auto abortCleanup = Cleanups.getTopCleanup();
 
   return {token, abortCleanup, allocation, deallocCleanup};
@@ -6239,8 +6486,7 @@ void SILGenFunction::emitYield(SILLocation loc,
   SmallVector<ManagedValue, 4> yieldArgs;
   SmallVector<DelayedArgument, 2> delayedArgs;
 
-  auto fnType = F.getLoweredFunctionTypeInContext(getTypeExpansionContext())
-    ->getUnsubstitutedType(SGM.M);
+  auto fnType = F.getLoweredFunctionTypeInContext()->getUnsubstitutedType(SGM.M);
   SmallVector<SILParameterInfo, 4> substYieldTys;
   for (auto origYield : fnType->getYields()) {
     substYieldTys.push_back(
@@ -7074,12 +7320,16 @@ bool AccessorBaseArgPreparer::shouldLoadBaseAddress() const {
     return base.isLValue() || base.isPlusZeroRValueOrTrivial()
       || !SGF.silConv.useLoweredAddresses();
 
-  case ParameterConvention::Indirect_In_Guaranteed:
+  case ParameterConvention::Indirect_In_Guaranteed: {
+    if (accessor.isBorrowAccessor()) {
+      return false;
+    }
     // We can pass the memory we already have at +0. The memory referred to
     // by the base should be already immutable unless it was lowered as an
     // lvalue.
     return base.isLValue()
       || !SGF.silConv.useLoweredAddresses();
+  }
 
   // If the accessor wants the value directly, we definitely have to
   // load.
@@ -7206,6 +7456,34 @@ ArgumentSource AccessorBaseArgPreparer::prepare() {
   return prepareAccessorObjectBaseArg();
 }
 
+ArgumentSource SILGenFunction::prepareAccessorBaseArgForFormalAccess(
+                                                      SILLocation loc,
+                                                      ManagedValue base,
+                                                      CanType baseFormalType,
+                                                      SILDeclRef accessor) {
+  if (!base) {
+    return ArgumentSource();
+  }
+    
+  base = base.formalAccessBorrow(*this, loc);
+  // If the base needs to be materialized, do so in
+  // the outer formal evaluation scope, since an addressor or
+  // other dependent value may want to point into the materialization.
+  auto &baseInfo = getConstantInfo(getTypeExpansionContext(), accessor);
+
+  if (!baseInfo.FormalPattern.isForeign()) {
+    auto baseFnTy = baseInfo.SILFnType;
+
+    if (baseFnTy->getSelfParameter().isFormalIndirect()
+        && base.getType().isObject()
+        && silConv.useLoweredAddresses()) {
+      base = base.formallyMaterialize(*this, loc);
+    }
+  }
+
+  return prepareAccessorBaseArg(loc, base, baseFormalType, accessor);
+}
+
 ArgumentSource SILGenFunction::prepareAccessorBaseArg(SILLocation loc,
                                                       ManagedValue base,
                                                       CanType baseFormalType,
@@ -7525,10 +7803,7 @@ ManagedValue SILGenFunction::emitAddressorAccessor(
 
   emission.addCallSite(loc, std::move(subscriptIndices));
 
-  // Unsafe{Mutable}Pointer<T> or
-  // (Unsafe{Mutable}Pointer<T>, Builtin.UnknownPointer) or
-  // (Unsafe{Mutable}Pointer<T>, Builtin.NativePointer) or
-  // (Unsafe{Mutable}Pointer<T>, Builtin.NativePointer?) or
+  // Result must be Unsafe{Mutable}Pointer<T>
   SmallVector<ManagedValue, 2> results;
   emission.apply().getAll(results);
 
@@ -7562,6 +7837,21 @@ ManagedValue SILGenFunction::emitAddressorAccessor(
   return ManagedValue::forLValue(address);
 }
 
+bool SILGenFunction::canUnwindAccessorDeclRef(SILDeclRef accessorRef) {
+  auto *accessor =
+      dyn_cast_or_null<AccessorDecl>(accessorRef.getAbstractFunctionDecl());
+  ASSERT(accessor && "only accessors can unwind");
+  auto kind = accessor->getAccessorKind();
+  ASSERT(isYieldingAccessor(kind) && "only yielding accessors can unwind");
+  if (!requiresFeatureCoroutineAccessors(kind)) {
+    // _read and _modify can unwind
+    return true;
+  }
+  // Coroutine accessors can only unwind with the experimental feature.
+  return getASTContext().LangOpts.hasFeature(
+      Feature::CoroutineAccessorsUnwindOnCallerError);
+}
+
 CleanupHandle
 SILGenFunction::emitCoroutineAccessor(SILLocation loc, SILDeclRef accessor,
                                       SubstitutionMap substitutions,
@@ -7597,11 +7887,41 @@ SILGenFunction::emitCoroutineAccessor(SILLocation loc, SILDeclRef accessor,
 
   emission.addCallSite(loc, std::move(subscriptIndices));
 
+  emission.setCanUnwind(canUnwindAccessorDeclRef(accessor));
+
   auto endApplyHandle = emission.applyCoroutine(yields);
 
   return endApplyHandle;
 }
 
+ManagedValue SILGenFunction::emitBorrowMutateAccessor(
+    SILLocation loc, SILDeclRef accessor, SubstitutionMap substitutions,
+    ArgumentSource &&selfValue, bool isSuper, bool isDirectUse,
+    PreparedArguments &&subscriptIndices, bool isOnSelfParameter) {
+  Callee callee = emitSpecializedAccessorFunctionRef(
+      *this, loc, accessor, substitutions, selfValue, isSuper, isDirectUse,
+      isOnSelfParameter);
+
+  CanAnyFunctionType accessType = callee.getSubstFormalType();
+
+  FormalEvaluationScope writebackScope(*this);
+  CallEmission emission(*this, std::move(callee), std::move(writebackScope));
+
+  // Self ->
+  emission.addSelfParam(loc, std::move(selfValue), accessType.getParams()[0]);
+  accessType = cast<AnyFunctionType>(accessType.getResult());
+
+  // Index or () if none.
+  if (subscriptIndices.isNull())
+    subscriptIndices.emplace({});
+
+  emission.addCallSite(loc, std::move(subscriptIndices));
+
+  emission.setCanUnwind(false);
+
+  return emission.applyBorrowMutateAccessor();
+}
+
 ManagedValue SILGenFunction::emitAsyncLetStart(
     SILLocation loc,
     SILValue taskOptions,
diff --git a/lib/SILGen/SILGenAvailability.cpp b/lib/SILGen/SILGenAvailability.cpp
new file mode 100644
index 0000000000000..e566259790f71
--- /dev/null
+++ b/lib/SILGen/SILGenAvailability.cpp
@@ -0,0 +1,397 @@
+//===--- SILGenAvailability.cpp - SILGen for availability queries ---------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "SILGenFunction.h"
+#include "SILGenFunctionBuilder.h"
+#include "Scope.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/Basic/Platform.h"
+#include "swift/SIL/SILDeclRef.h"
+
+using namespace swift;
+using namespace Lowering;
+
+/// Emit literals for each of element in `values`, populating `results` with the
+/// corresponding `SILValue`.
+static void emitIntegerLiterals(SILLocation loc, SILGenBuilder &B,
+                                ASTContext &ctx, ArrayRef<unsigned> values,
+                                llvm::SmallVectorImpl<SILValue> &results) {
+
+  SILType wordType = SILType::getBuiltinWordType(ctx);
+  for (auto value : values) {
+    results.emplace_back(B.createIntegerLiteral(loc, wordType, value));
+  }
+}
+
+static SILValue emitAvailabilityCheck(SILGenFunction &SGF, SILLocation loc,
+                                      const AvailabilityQuery &query) {
+  auto &ctx = SGF.getASTContext();
+  SILType i1 = SILType::getBuiltinIntegerType(1, SGF.getASTContext());
+  auto &B = SGF.B;
+
+  // If the query's result is known at compile time, emit a constant.
+  if (auto constantResult = query.getConstantResult())
+    return B.createIntegerLiteral(loc, i1, *constantResult);
+
+  llvm::SmallVector<unsigned, 6> rawArgs;
+  auto queryDecl = query.getDynamicQueryDeclAndArguments(rawArgs, ctx);
+
+  // FIXME: [availability] Once dynamic custom domains have decls, DEBUG_ASSERT.
+  if (!queryDecl)
+    return B.createIntegerLiteral(loc, i1, !query.isUnavailability());
+
+  auto queryType = queryDecl->getInterfaceType()->getAs<FunctionType>();
+  ASSERT(queryType);
+  ASSERT(queryType->getResult()->getAs<BuiltinIntegerType>());
+
+  auto queryParams = queryType->getParams();
+  ASSERT(rawArgs.size() == queryParams.size());
+
+  llvm::SmallVector<SILValue, 6> silArgs;
+  emitIntegerLiterals(loc, B, ctx, rawArgs, silArgs);
+
+  auto declRef = SILDeclRef(queryDecl);
+  SILValue availabilityGTEFn = SGF.emitGlobalFunctionRef(
+      loc, declRef,
+      SGF.getConstantInfo(SGF.getTypeExpansionContext(), declRef));
+
+  SILValue result =
+      B.createApply(loc, availabilityGTEFn, SubstitutionMap(), silArgs);
+
+  // If this is an unavailability check, invert the result using 1-bit xor
+  // with 1.
+  if (query.isUnavailability()) {
+    SILType i1 = SILType::getBuiltinIntegerType(1, ctx);
+    SILValue one = B.createIntegerLiteral(loc, i1, 1);
+    result = B.createBuiltinBinaryFunction(loc, "xor", i1, i1, {result, one});
+  }
+
+  return result;
+}
+
+/// Given a value, extracts all elements to `result` from this value if it's a
+/// tuple. Otherwise, add this value directly to `result`.
+static void extractAllElements(SILValue val, SILLocation loc,
+                               SILBuilder &builder,
+                               SmallVectorImpl<SILValue> &result) {
+  auto &fn = builder.getFunction();
+  auto tupleType = val->getType().getAs<TupleType>();
+  if (!tupleType) {
+    result.push_back(val);
+    return;
+  }
+  if (!fn.hasOwnership()) {
+    for (auto i : range(tupleType->getNumElements()))
+      result.push_back(builder.createTupleExtract(loc, val, i));
+    return;
+  }
+  if (tupleType->getNumElements() == 0)
+    return;
+  builder.emitDestructureValueOperation(loc, val, result);
+}
+
+static Type getResultInterfaceType(AbstractFunctionDecl *AFD) {
+  if (auto *FD = dyn_cast<FuncDecl>(AFD))
+    return FD->getResultInterfaceType();
+
+  if (auto *CD = dyn_cast<ConstructorDecl>(AFD))
+    return CD->getResultInterfaceType();
+
+  llvm_unreachable("Unhandled AbstractFunctionDecl type");
+}
+
+static std::optional<AvailabilityQuery>
+getAvailabilityQueryForBackDeployment(AbstractFunctionDecl *AFD) {
+  auto &ctx = AFD->getASTContext();
+  if (ctx.LangOpts.TargetVariant) {
+    auto primaryAttrAndRange = AFD->getBackDeployedAttrAndRange(ctx);
+    auto variantAttrAndRange =
+        AFD->getBackDeployedAttrAndRange(ctx, /*forTargetVariant=*/true);
+
+    if (!primaryAttrAndRange && !variantAttrAndRange)
+      return std::nullopt;
+
+    auto attr = primaryAttrAndRange ? primaryAttrAndRange->first
+                                    : variantAttrAndRange->first;
+    std::optional<AvailabilityRange> primaryRange;
+    if (primaryAttrAndRange)
+      primaryRange = primaryAttrAndRange->second;
+
+    std::optional<AvailabilityRange> variantRange;
+    if (variantAttrAndRange)
+      variantRange = variantAttrAndRange->second;
+
+    return AvailabilityQuery::dynamic(attr->getAvailabilityDomain(),
+                                      primaryRange, variantRange);
+  }
+
+  if (auto primaryAttrAndRange = AFD->getBackDeployedAttrAndRange(ctx))
+    return AvailabilityQuery::dynamic(
+        primaryAttrAndRange->first->getAvailabilityDomain(),
+        primaryAttrAndRange->second, std::nullopt);
+
+  return std::nullopt;
+}
+
+/// Emit the following branch SIL instruction:
+/// \verbatim
+/// if #available(OSVersion) {
+///   <availableBB>
+/// } else {
+///   <unavailableBB>
+/// }
+/// \endverbatim
+static void emitBackDeployIfAvailableCondition(SILGenFunction &SGF,
+                                               AbstractFunctionDecl *AFD,
+                                               SILLocation loc,
+                                               SILBasicBlock *availableBB,
+                                               SILBasicBlock *unavailableBB) {
+  auto &B = SGF.B;
+  SILValue booleanTestValue;
+  if (auto query = getAvailabilityQueryForBackDeployment(AFD)) {
+    booleanTestValue = emitAvailabilityCheck(SGF, loc, *query);
+  } else {
+    // Some logic has gone wrong if we've gotten here but lets fail gracefully
+    // and emit a branch that always succeeds.
+    SILType i1 = SILType::getBuiltinIntegerType(1, SGF.getASTContext());
+    booleanTestValue = B.createIntegerLiteral(loc, i1, true);
+  }
+  B.createCondBranch(loc, booleanTestValue, availableBB, unavailableBB);
+}
+
+/// Emits a function or method application, forwarding parameters.
+static void emitBackDeployForwardApplyAndReturnOrThrow(
+    SILGenFunction &SGF, AbstractFunctionDecl *AFD, SILLocation loc,
+    SILDeclRef function, SmallVector<SILValue, 8> &params) {
+  // Only statically dispatched class methods are supported.
+  if (auto classDecl = dyn_cast<ClassDecl>(AFD->getDeclContext())) {
+    assert(classDecl->isFinal() || AFD->isFinal() ||
+           AFD->hasForcedStaticDispatch());
+  }
+
+  TypeExpansionContext TEC = SGF.getTypeExpansionContext();
+  auto fnType = SGF.SGM.Types.getConstantOverrideType(TEC, function);
+  auto silFnType =
+      SILType::getPrimitiveObjectType(fnType).castTo<SILFunctionType>();
+  SILFunctionConventions fnConv(silFnType, SGF.SGM.M);
+
+  SILValue functionRef = SGF.emitGlobalFunctionRef(loc, function);
+  auto subs = SGF.F.getForwardingSubstitutionMap();
+  SmallVector<SILValue, 4> directResults;
+
+  // If the function is a coroutine, we need to use 'begin_apply'.
+  if (silFnType->isCoroutine()) {
+    assert(!silFnType->hasErrorResult() && "throwing coroutine?");
+
+    // Apply the coroutine, yield the result, and finally branch to either the
+    // terminal return or unwind basic block via intermediate basic blocks. The
+    // intermediates are needed to avoid forming critical edges.
+    SILBasicBlock *resumeBB = SGF.createBasicBlock();
+    SILBasicBlock *unwindBB = SGF.createBasicBlock();
+
+    auto *apply = SGF.B.createBeginApply(loc, functionRef, subs, params);
+    SmallVector<SILValue, 4> rawResults;
+    for (auto result : apply->getAllResults())
+      rawResults.push_back(result);
+
+    auto token = rawResults.pop_back_val();
+    SGF.B.createYield(loc, rawResults, resumeBB, unwindBB);
+
+    // Emit resume block.
+    SGF.B.emitBlock(resumeBB);
+    SGF.B.createEndApply(loc, token,
+                         SILType::getEmptyTupleType(SGF.getASTContext()));
+    SGF.B.createBranch(loc, SGF.ReturnDest.getBlock());
+
+    // Emit unwind block.
+    SGF.B.emitBlock(unwindBB);
+    SGF.B.createEndApply(loc, token,
+                         SILType::getEmptyTupleType(SGF.getASTContext()));
+    SGF.B.createBranch(loc, SGF.CoroutineUnwindDest.getBlock());
+    return;
+  }
+
+  // Use try_apply for functions that throw.
+  if (silFnType->hasErrorResult()) {
+    // Apply the throwing function and forward the results and the error to the
+    // return/throw blocks via intermediate basic blocks. The intermediates
+    // are needed to avoid forming critical edges.
+    SILBasicBlock *normalBB = SGF.createBasicBlock();
+    SILBasicBlock *errorBB = SGF.createBasicBlock();
+
+    SGF.B.createTryApply(loc, functionRef, subs, params, normalBB, errorBB);
+
+    // Emit error block.
+    SGF.B.emitBlock(errorBB);
+    ManagedValue error =
+        SGF.B.createPhi(SGF.F.mapTypeIntoContext(fnConv.getSILErrorType(TEC)),
+                        OwnershipKind::Owned);
+    SGF.B.createBranch(loc, SGF.ThrowDest.getBlock(), {error});
+
+    // Emit normal block.
+    SGF.B.emitBlock(normalBB);
+    SILValue result = normalBB->createPhiArgument(
+        SGF.F.mapTypeIntoContext(fnConv.getSILResultType(TEC)),
+        OwnershipKind::Owned);
+    SmallVector<SILValue, 4> directResults;
+    extractAllElements(result, loc, SGF.B, directResults);
+
+    SGF.B.createBranch(loc, SGF.ReturnDest.getBlock(), directResults);
+    return;
+  }
+
+  // The original function is neither throwing nor a coroutine. Apply it and
+  // forward its results straight to the return block.
+  auto *apply = SGF.B.createApply(loc, functionRef, subs, params);
+  extractAllElements(apply, loc, SGF.B, directResults);
+
+  SGF.B.createBranch(loc, SGF.ReturnDest.getBlock(), directResults);
+}
+
+SILValue
+SILGenFunction::emitIfAvailableQuery(SILLocation loc,
+                                     PoundAvailableInfo *availability) {
+  auto &ctx = getASTContext();
+  SILType i1 = SILType::getBuiltinIntegerType(1, ctx);
+  auto query = availability->getAvailabilityQuery();
+
+  // The query may not have been computed by Sema under the following
+  // conditions:
+  // - Availability checking was disabled (-disable-availability-checking).
+  // - The query was marked invalid in the AST for a non-fatal reason.
+  //
+  // Otherwise, there's a bug in Sema.
+  DEBUG_ASSERT(query || availability->isInvalid() ||
+               ctx.LangOpts.DisableAvailabilityChecking);
+
+  // If Sema skipped the query then treat the condition as if it always
+  // evaluates true.
+  if (!query)
+    return B.createIntegerLiteral(loc, i1, !availability->isUnavailability());
+
+  return emitAvailabilityCheck(*this, loc, *query);
+}
+
+bool SILGenModule::requiresBackDeploymentThunk(ValueDecl *decl,
+                                               ResilienceExpansion expansion) {
+  auto &ctx = getASTContext();
+  auto attrAndRange = decl->getBackDeployedAttrAndRange(ctx);
+  if (!attrAndRange)
+    return false;
+
+  switch (expansion) {
+  case ResilienceExpansion::Minimal:
+    // In a minimal resilience expansion we must always call the back deployment
+    // thunk since we can't predict the deployment targets of the modules that
+    // might inline the call.
+    return true;
+  case ResilienceExpansion::Maximal:
+    // FIXME: We can skip thunking if we're in the same module.
+    break;
+  }
+
+  // Use of a back deployment thunk is unnecessary if the deployment target is
+  // high enough that the ABI implementation of the back deployed declaration is
+  // guaranteed to be available.
+  auto deploymentAvailability = AvailabilityRange::forDeploymentTarget(ctx);
+  if (deploymentAvailability.isContainedIn(attrAndRange->second))
+    return false;
+
+  return true;
+}
+
+void SILGenFunction::emitBackDeploymentThunk(SILDeclRef thunk) {
+  // Generate code equivalent to:
+  //
+  //  func X_thunk(...) async throws -> ... {
+  //    if #available(...) {
+  //      return try await X(...)
+  //    } else {
+  //      return try await X_fallback(...)
+  //    }
+  //  }
+
+  assert(thunk.isBackDeploymentThunk());
+
+  auto loc = thunk.getAsRegularLocation();
+  loc.markAutoGenerated();
+  Scope scope(Cleanups, CleanupLocation(loc));
+  auto AFD = cast<AbstractFunctionDecl>(thunk.getDecl());
+
+  F.setGenericEnvironment(SGM.Types.getConstantGenericEnvironment(thunk));
+
+  // Generate the thunk prolog by collecting parameters.
+  SmallVector<ManagedValue, 4> params;
+  SmallVector<ManagedValue, 4> indirectParams;
+  SmallVector<ManagedValue, 4> indirectErrorResults;
+  ManagedValue implicitIsolationParam;
+  collectThunkParams(loc, params, &indirectParams, &indirectErrorResults,
+                     &implicitIsolationParam);
+
+  // Build up the list of arguments that we're going to invoke the real
+  // function with.
+  SmallVector<SILValue, 8> paramsForForwarding;
+  for (auto indirectParam : indirectParams) {
+    paramsForForwarding.emplace_back(indirectParam.getLValueAddress());
+  }
+  for (auto indirectErrorResult : indirectErrorResults) {
+    paramsForForwarding.emplace_back(indirectErrorResult.getLValueAddress());
+  }
+  if (implicitIsolationParam) {
+    paramsForForwarding.emplace_back(implicitIsolationParam.forward(*this));
+  }
+
+  for (auto param : params) {
+    // We're going to directly call either the original function or the fallback
+    // function with these arguments and then return. Therefore we just forward
+    // the arguments instead of handling their ownership conventions.
+    paramsForForwarding.emplace_back(param.forward(*this));
+  }
+
+  prepareEpilog(AFD,
+                getResultInterfaceType(AFD),
+                AFD->getEffectiveThrownErrorType(),
+                CleanupLocation(AFD));
+
+  SILBasicBlock *availableBB = createBasicBlock("availableBB");
+  SILBasicBlock *unavailableBB = createBasicBlock("unavailableBB");
+
+  //  if #available(...) {
+  //    <availableBB>
+  //  } else {
+  //    <unavailableBB>
+  //  }
+  emitBackDeployIfAvailableCondition(*this, AFD, loc, availableBB,
+                                     unavailableBB);
+
+  // <availableBB>:
+  //   return (try)? (await)? (self.)?X(...)
+  {
+    B.emitBlock(availableBB);
+    SILDeclRef original =
+        thunk.asBackDeploymentKind(SILDeclRef::BackDeploymentKind::None);
+    emitBackDeployForwardApplyAndReturnOrThrow(*this, AFD, loc, original,
+                                               paramsForForwarding);
+  }
+
+  // <unavailableBB>:
+  //   return (try)? (await)? (self.)?X_fallback(...)
+  {
+    B.emitBlock(unavailableBB);
+    SILDeclRef fallback =
+        thunk.asBackDeploymentKind(SILDeclRef::BackDeploymentKind::Fallback);
+    emitBackDeployForwardApplyAndReturnOrThrow(*this, AFD, loc, fallback,
+                                               paramsForForwarding);
+  }
+
+  emitEpilog(AFD);
+}
diff --git a/lib/SILGen/SILGenBackDeploy.cpp b/lib/SILGen/SILGenBackDeploy.cpp
deleted file mode 100644
index b635ef0adf50b..0000000000000
--- a/lib/SILGen/SILGenBackDeploy.cpp
+++ /dev/null
@@ -1,315 +0,0 @@
-//===--- SILGenBackDeploy.cpp - SILGen for back deployment ----------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-#include "SILGenFunction.h"
-#include "SILGenFunctionBuilder.h"
-#include "Scope.h"
-#include "swift/Basic/Platform.h"
-#include "swift/Basic/Assertions.h"
-#include "swift/SIL/SILDeclRef.h"
-
-using namespace swift;
-using namespace Lowering;
-
-/// Given a value, extracts all elements to `result` from this value if it's a
-/// tuple. Otherwise, add this value directly to `result`.
-static void extractAllElements(SILValue val, SILLocation loc,
-                               SILBuilder &builder,
-                               SmallVectorImpl<SILValue> &result) {
-  auto &fn = builder.getFunction();
-  auto tupleType = val->getType().getAs<TupleType>();
-  if (!tupleType) {
-    result.push_back(val);
-    return;
-  }
-  if (!fn.hasOwnership()) {
-    for (auto i : range(tupleType->getNumElements()))
-      result.push_back(builder.createTupleExtract(loc, val, i));
-    return;
-  }
-  if (tupleType->getNumElements() == 0)
-    return;
-  builder.emitDestructureValueOperation(loc, val, result);
-}
-
-static Type getResultInterfaceType(AbstractFunctionDecl *AFD) {
-  if (auto *FD = dyn_cast<FuncDecl>(AFD))
-    return FD->getResultInterfaceType();
-
-  if (auto *CD = dyn_cast<ConstructorDecl>(AFD))
-    return CD->getResultInterfaceType();
-
-  llvm_unreachable("Unhandled AbstractFunctionDecl type");
-}
-
-static SILValue emitZipperedBackDeployIfAvailableBooleanTestValue(
-    SILGenFunction &SGF, AbstractFunctionDecl *AFD, SILLocation loc,
-    SILBasicBlock *availableBB, SILBasicBlock *unavailableBB) {
-  auto &ctx = SGF.getASTContext();
-  assert(ctx.LangOpts.TargetVariant);
-
-  VersionRange OSVersion = VersionRange::all();
-  if (auto version = AFD->getBackDeployedBeforeOSVersion(ctx)) {
-    OSVersion = VersionRange::allGTE(*version);
-  }
-
-  VersionRange VariantOSVersion = VersionRange::all();
-  if (auto version =
-          AFD->getBackDeployedBeforeOSVersion(ctx, /*forTargetVariant=*/true)) {
-    VariantOSVersion = VersionRange::allGTE(*version);
-  }
-
-  return SGF.emitZipperedOSVersionRangeCheck(loc, OSVersion, VariantOSVersion);
-}
-
-/// Emit the following branch SIL instruction:
-/// \verbatim
-/// if #available(OSVersion) {
-///   <availableBB>
-/// } else {
-///   <unavailableBB>
-/// }
-/// \endverbatim
-static void emitBackDeployIfAvailableCondition(SILGenFunction &SGF,
-                                               AbstractFunctionDecl *AFD,
-                                               SILLocation loc,
-                                               SILBasicBlock *availableBB,
-                                               SILBasicBlock *unavailableBB) {
-  if (SGF.getASTContext().LangOpts.TargetVariant) {
-    SILValue booleanTestValue =
-        emitZipperedBackDeployIfAvailableBooleanTestValue(
-            SGF, AFD, loc, availableBB, unavailableBB);
-    SGF.B.createCondBranch(loc, booleanTestValue, availableBB, unavailableBB);
-    return;
-  }
-
-  auto version = AFD->getBackDeployedBeforeOSVersion(SGF.SGM.getASTContext());
-  VersionRange OSVersion = VersionRange::empty();
-  if (version.has_value()) {
-    OSVersion = VersionRange::allGTE(*version);
-  }
-
-  SILValue booleanTestValue;
-  if (OSVersion.isEmpty() || OSVersion.isAll()) {
-    // If there's no check for the current platform, this condition is
-    // trivially true.
-    SILType i1 = SILType::getBuiltinIntegerType(1, SGF.getASTContext());
-    booleanTestValue = SGF.B.createIntegerLiteral(loc, i1, 1);
-  } else {
-    bool isMacCatalyst =
-        tripleIsMacCatalystEnvironment(SGF.getASTContext().LangOpts.Target);
-    booleanTestValue =
-        SGF.emitOSVersionRangeCheck(loc, OSVersion, isMacCatalyst);
-  }
-
-  SGF.B.createCondBranch(loc, booleanTestValue, availableBB, unavailableBB);
-}
-
-/// Emits a function or method application, forwarding parameters.
-static void emitBackDeployForwardApplyAndReturnOrThrow(
-    SILGenFunction &SGF, AbstractFunctionDecl *AFD, SILLocation loc,
-    SILDeclRef function, SmallVector<SILValue, 8> &params) {
-  // Only statically dispatched class methods are supported.
-  if (auto classDecl = dyn_cast<ClassDecl>(AFD->getDeclContext())) {
-    assert(classDecl->isFinal() || AFD->isFinal() ||
-           AFD->hasForcedStaticDispatch());
-  }
-
-  TypeExpansionContext TEC = SGF.getTypeExpansionContext();
-  auto fnType = SGF.SGM.Types.getConstantOverrideType(TEC, function);
-  auto silFnType =
-      SILType::getPrimitiveObjectType(fnType).castTo<SILFunctionType>();
-  SILFunctionConventions fnConv(silFnType, SGF.SGM.M);
-
-  SILValue functionRef = SGF.emitGlobalFunctionRef(loc, function);
-  auto subs = SGF.F.getForwardingSubstitutionMap();
-  SmallVector<SILValue, 4> directResults;
-
-  // If the function is a coroutine, we need to use 'begin_apply'.
-  if (silFnType->isCoroutine()) {
-    assert(!silFnType->hasErrorResult() && "throwing coroutine?");
-
-    // Apply the coroutine, yield the result, and finally branch to either the
-    // terminal return or unwind basic block via intermediate basic blocks. The
-    // intermediates are needed to avoid forming critical edges.
-    SILBasicBlock *resumeBB = SGF.createBasicBlock();
-    SILBasicBlock *unwindBB = SGF.createBasicBlock();
-
-    auto *apply = SGF.B.createBeginApply(loc, functionRef, subs, params);
-    SmallVector<SILValue, 4> rawResults;
-    for (auto result : apply->getAllResults())
-      rawResults.push_back(result);
-
-    auto token = rawResults.pop_back_val();
-    SGF.B.createYield(loc, rawResults, resumeBB, unwindBB);
-
-    // Emit resume block.
-    SGF.B.emitBlock(resumeBB);
-    SGF.B.createEndApply(loc, token,
-                         SILType::getEmptyTupleType(SGF.getASTContext()));
-    SGF.B.createBranch(loc, SGF.ReturnDest.getBlock());
-
-    // Emit unwind block.
-    SGF.B.emitBlock(unwindBB);
-    SGF.B.createEndApply(loc, token,
-                         SILType::getEmptyTupleType(SGF.getASTContext()));
-    SGF.B.createBranch(loc, SGF.CoroutineUnwindDest.getBlock());
-    return;
-  }
-
-  // Use try_apply for functions that throw.
-  if (silFnType->hasErrorResult()) {
-    // Apply the throwing function and forward the results and the error to the
-    // return/throw blocks via intermediate basic blocks. The intermediates
-    // are needed to avoid forming critical edges.
-    SILBasicBlock *normalBB = SGF.createBasicBlock();
-    SILBasicBlock *errorBB = SGF.createBasicBlock();
-
-    SGF.B.createTryApply(loc, functionRef, subs, params, normalBB, errorBB);
-
-    // Emit error block.
-    SGF.B.emitBlock(errorBB);
-    ManagedValue error =
-        SGF.B.createPhi(SGF.F.mapTypeIntoContext(fnConv.getSILErrorType(TEC)),
-                        OwnershipKind::Owned);
-    SGF.B.createBranch(loc, SGF.ThrowDest.getBlock(), {error});
-
-    // Emit normal block.
-    SGF.B.emitBlock(normalBB);
-    SILValue result = normalBB->createPhiArgument(
-        SGF.F.mapTypeIntoContext(fnConv.getSILResultType(TEC)),
-        OwnershipKind::Owned);
-    SmallVector<SILValue, 4> directResults;
-    extractAllElements(result, loc, SGF.B, directResults);
-
-    SGF.B.createBranch(loc, SGF.ReturnDest.getBlock(), directResults);
-    return;
-  }
-
-  // The original function is neither throwing nor a coroutine. Apply it and
-  // forward its results straight to the return block.
-  auto *apply = SGF.B.createApply(loc, functionRef, subs, params);
-  extractAllElements(apply, loc, SGF.B, directResults);
-
-  SGF.B.createBranch(loc, SGF.ReturnDest.getBlock(), directResults);
-}
-
-bool SILGenModule::requiresBackDeploymentThunk(ValueDecl *decl,
-                                               ResilienceExpansion expansion) {
-  auto &ctx = getASTContext();
-  auto backDeployBeforeVersion = decl->getBackDeployedBeforeOSVersion(ctx);
-  if (!backDeployBeforeVersion)
-    return false;
-
-  switch (expansion) {
-  case ResilienceExpansion::Minimal:
-    // In a minimal resilience expansion we must always call the back deployment
-    // thunk since we can't predict the deployment targets of the modules that
-    // might inline the call.
-    return true;
-  case ResilienceExpansion::Maximal:
-    // FIXME: We can skip thunking if we're in the same module.
-    break;
-  }
-
-  // Use of a back deployment thunk is unnecessary if the deployment target is
-  // high enough that the ABI implementation of the back deployed declaration is
-  // guaranteed to be available.
-  auto deploymentAvailability = AvailabilityRange::forDeploymentTarget(ctx);
-  auto declAvailability = AvailabilityRange(*backDeployBeforeVersion);
-  if (deploymentAvailability.isContainedIn(declAvailability))
-    return false;
-
-  return true;
-}
-
-void SILGenFunction::emitBackDeploymentThunk(SILDeclRef thunk) {
-  // Generate code equivalent to:
-  //
-  //  func X_thunk(...) async throws -> ... {
-  //    if #available(...) {
-  //      return try await X(...)
-  //    } else {
-  //      return try await X_fallback(...)
-  //    }
-  //  }
-
-  assert(thunk.isBackDeploymentThunk());
-
-  auto loc = thunk.getAsRegularLocation();
-  loc.markAutoGenerated();
-  Scope scope(Cleanups, CleanupLocation(loc));
-  auto AFD = cast<AbstractFunctionDecl>(thunk.getDecl());
-
-  F.setGenericEnvironment(SGM.Types.getConstantGenericEnvironment(thunk));
-
-  // Generate the thunk prolog by collecting parameters.
-  SmallVector<ManagedValue, 4> params;
-  SmallVector<ManagedValue, 4> indirectParams;
-  SmallVector<ManagedValue, 4> indirectErrorResults;
-  collectThunkParams(loc, params, &indirectParams, &indirectErrorResults);
-
-  // Build up the list of arguments that we're going to invoke the real
-  // function with.
-  SmallVector<SILValue, 8> paramsForForwarding;
-  for (auto indirectParam : indirectParams) {
-    paramsForForwarding.emplace_back(indirectParam.getLValueAddress());
-  }
-  for (auto indirectErrorResult : indirectErrorResults) {
-    paramsForForwarding.emplace_back(indirectErrorResult.getLValueAddress());
-  }
-
-  for (auto param : params) {
-    // We're going to directly call either the original function or the fallback
-    // function with these arguments and then return. Therefore we just forward
-    // the arguments instead of handling their ownership conventions.
-    paramsForForwarding.emplace_back(param.forward(*this));
-  }
-
-  prepareEpilog(AFD,
-                getResultInterfaceType(AFD),
-                AFD->getEffectiveThrownErrorType(),
-                CleanupLocation(AFD));
-
-  SILBasicBlock *availableBB = createBasicBlock("availableBB");
-  SILBasicBlock *unavailableBB = createBasicBlock("unavailableBB");
-
-  //  if #available(...) {
-  //    <availableBB>
-  //  } else {
-  //    <unavailableBB>
-  //  }
-  emitBackDeployIfAvailableCondition(*this, AFD, loc, availableBB,
-                                     unavailableBB);
-
-  // <availableBB>:
-  //   return (try)? (await)? (self.)?X(...)
-  {
-    B.emitBlock(availableBB);
-    SILDeclRef original =
-        thunk.asBackDeploymentKind(SILDeclRef::BackDeploymentKind::None);
-    emitBackDeployForwardApplyAndReturnOrThrow(*this, AFD, loc, original,
-                                               paramsForForwarding);
-  }
-
-  // <unavailableBB>:
-  //   return (try)? (await)? (self.)?X_fallback(...)
-  {
-    B.emitBlock(unavailableBB);
-    SILDeclRef fallback =
-        thunk.asBackDeploymentKind(SILDeclRef::BackDeploymentKind::Fallback);
-    emitBackDeployForwardApplyAndReturnOrThrow(*this, AFD, loc, fallback,
-                                               paramsForForwarding);
-  }
-
-  emitEpilog(AFD);
-}
diff --git a/lib/SILGen/SILGenBridging.cpp b/lib/SILGen/SILGenBridging.cpp
index 424fc38023f40..ea0c664284ff0 100644
--- a/lib/SILGen/SILGenBridging.cpp
+++ b/lib/SILGen/SILGenBridging.cpp
@@ -1315,8 +1315,10 @@ static SILValue emitObjCUnconsumedArgument(SILGenFunction &SGF,
                                            SILLocation loc,
                                            SILValue arg) {
   auto &lowering = SGF.getTypeLowering(arg->getType());
-  // If address-only, make a +1 copy and operate on that.
-  if (lowering.isAddressOnly() && SGF.useLoweredAddresses()) {
+  // If arg is non-trivial and has an address type, make a +1 copy and operate
+  // on that.
+  if (!lowering.isTrivial() && arg->getType().isAddress() &&
+      SGF.useLoweredAddresses()) {
     auto tmp = SGF.emitTemporaryAllocation(loc, arg->getType().getObjectType());
     SGF.B.createCopyAddr(loc, arg, tmp, IsNotTake, IsInitialization);
     return tmp;
@@ -1373,11 +1375,16 @@ emitObjCThunkArguments(SILGenFunction &SGF, SILLocation loc, SILDeclRef thunk,
   auto inputs = objcFnTy->getParameters();
   auto nativeInputs = swiftFnTy->getParameters();
   auto fnConv = SGF.silConv.getFunctionConventions(swiftFnTy);
-  assert(nativeInputs.size() == bridgedFormalTypes.size());
-  assert(nativeInputs.size() == nativeFormalTypes.size());
+  bool nativeInputsHasImplicitIsolatedParam = false;
+  if (auto param = swiftFnTy->maybeGetIsolatedParameter())
+    nativeInputsHasImplicitIsolatedParam = param->hasOption(SILParameterInfo::ImplicitLeading);
+  assert(nativeInputs.size() - unsigned(nativeInputsHasImplicitIsolatedParam) == bridgedFormalTypes.size());
+  assert(nativeInputs.size() - unsigned(nativeInputsHasImplicitIsolatedParam) == nativeFormalTypes.size());
   assert(inputs.size() ==
            nativeInputs.size() + unsigned(foreignError.has_value())
-                               + unsigned(foreignAsync.has_value()));
+                               + unsigned(foreignAsync.has_value()) -
+         unsigned(nativeInputsHasImplicitIsolatedParam));
+
   for (unsigned i = 0, e = inputs.size(); i < e; ++i) {
     SILType argTy = SGF.getSILType(inputs[i], objcFnTy);
     SILValue arg = SGF.F.begin()->createFunctionArgument(argTy);
@@ -1423,13 +1430,13 @@ emitObjCThunkArguments(SILGenFunction &SGF, SILLocation loc, SILDeclRef thunk,
            + unsigned(foreignAsync.has_value())
         == objcFnTy->getParameters().size() &&
          "objc inputs don't match number of arguments?!");
-  assert(bridgedArgs.size() == swiftFnTy->getParameters().size() &&
+  assert(bridgedArgs.size() == swiftFnTy->getParameters().size() - bool(nativeInputsHasImplicitIsolatedParam) &&
          "swift inputs don't match number of arguments?!");
   assert((foreignErrorSlot || !foreignError) &&
          "didn't find foreign error slot");
 
   // Bridge the input types.
-  assert(bridgedArgs.size() == nativeInputs.size());
+  assert(bridgedArgs.size() == nativeInputs.size() - bool(nativeInputsHasImplicitIsolatedParam));
   for (unsigned i = 0, size = bridgedArgs.size(); i < size; ++i) {
     // Consider the bridged values to be "call results" since they're coming
     // from potentially nil-unsound ObjC callers.
@@ -1448,6 +1455,11 @@ emitObjCThunkArguments(SILGenFunction &SGF, SILLocation loc, SILDeclRef thunk,
       auto buf = SGF.emitTemporaryAllocation(loc, native.getType());
       native.forwardInto(SGF, loc, buf);
       native = SGF.emitManagedBufferWithCleanup(buf);
+    } else if (!fnConv.isSILIndirect(nativeInputs[i]) &&
+               native.getType().isAddress() && SGF.useLoweredAddresses()) {
+      // Load the value if the argument has an address type and the native
+      // function expects the argument to be passed directly.
+      native = SGF.emitManagedLoadCopy(loc, native.getValue());
     }
 
     if (nativeInputs[i].isConsumedInCaller()) {
@@ -1656,6 +1668,31 @@ void SILGenFunction::emitNativeToForeignThunk(SILDeclRef thunk) {
   // we will deallocate it too early.
   Scope argScope(Cleanups, CleanupLocation(loc));
 
+  // See if our native function has an implicitly isolated parameter. In such a
+  // case, we need to pass in the isolation.
+  if (auto isolatedParameter = substTy->maybeGetIsolatedParameter();
+      isolatedParameter && isolatedParameter->hasOption(SILParameterInfo::ImplicitLeading)) {
+    assert(F.isAsync() && "Can only be async");
+    assert(isolation && "No isolation?!");
+    switch (isolation->getKind()) {
+    case ActorIsolation::Unspecified:
+    case ActorIsolation::Nonisolated:
+    case ActorIsolation::NonisolatedUnsafe:
+    case ActorIsolation::CallerIsolationInheriting:
+      args.push_back(emitNonIsolatedIsolation(loc).getValue());
+      break;
+    case ActorIsolation::ActorInstance:
+      llvm::report_fatal_error("Should never see this");
+      break;
+    case ActorIsolation::GlobalActor:
+      args.push_back(emitLoadGlobalActorExecutor(isolation->getGlobalActor()));
+      break;
+    case ActorIsolation::Erased:
+      llvm::report_fatal_error("Should never see this");
+      break;
+    }
+  }
+
   // Bridge the arguments.
   SILValue foreignErrorSlot;
   SILValue foreignAsyncSlot;
@@ -2117,28 +2154,45 @@ void SILGenFunction::emitForeignToNativeThunk(SILDeclRef thunk) {
     indirectResult = F.begin()->createFunctionArgument(
         nativeConv.getSingleSILResultType(F.getTypeExpansionContext()));
   }
-  
+
+  // Before we do anything, see if our function type is async and has an
+  // implicit isolated parameter. In such a case, we need to implicitly insert
+  // it here before we insert other parameters.
+  //
+  // NOTE: We do not jump to it or do anything further since as mentioned above,
+  // we might switch to the callee's actor as part of making the call... but we
+  // don't need to do anything further than that because we're going to
+  // immediately return.
+  bool hasImplicitIsolatedParameter = false;
+  if (auto isolatedParameter = nativeFnTy->maybeGetIsolatedParameter();
+      isolatedParameter && nativeFnTy->isAsync() &&
+      isolatedParameter->hasOption(SILParameterInfo::ImplicitLeading)) {
+    auto loweredTy = getLoweredTypeForFunctionArgument(
+        isolatedParameter->getArgumentType(&F));
+    F.begin()->createFunctionArgument(loweredTy);
+    hasImplicitIsolatedParameter = true;
+  }
+
   // Forward the arguments.
   SmallVector<SILValue, 8> params;
 
   bindParametersForForwarding(fd->getParameters(), params);
-  if (thunk.kind != SILDeclRef::Kind::Allocator)
-    if (auto *selfDecl = fd->getImplicitSelfDecl())
-      bindParameterForForwarding(selfDecl, params);
-
-  // For allocating constructors, 'self' is a metatype, not the 'self' value
-  // formally present in the constructor body.
   Type allocatorSelfType;
-  if (thunk.kind == SILDeclRef::Kind::Allocator) {
-    auto *selfDecl = fd->getImplicitSelfDecl();
-    allocatorSelfType = F.mapTypeIntoContext(
-      fd->getDeclContext()->getSelfInterfaceType());
-
-    auto selfMetatype =
-      CanMetatypeType::get(allocatorSelfType->getCanonicalType());
-    auto selfArg = F.begin()->createFunctionArgument(
-        getLoweredLoadableType(selfMetatype), selfDecl);
+  if (auto *selfDecl = fd->getImplicitSelfDecl()) {
+    // The self declaration sometimes differ in dynamic-self-ness from the
+    // lowered function type, so get the self parameter type from the function
+    // type rather than the declaration.
+    auto selfArgTy = F.getLoweredFunctionType()->getSelfParameter()
+      .getSILStorageType(getModule(), F.getLoweredFunctionType(), getTypeExpansionContext());
+    auto selfArg = F.begin()->createFunctionArgument(F.mapTypeIntoContext(selfArgTy), selfDecl);
     params.push_back(selfArg);
+
+    // For allocating constructors, 'self' is a metatype, not the 'self' value
+    // formally present in the constructor body.
+    if (thunk.kind == SILDeclRef::Kind::Allocator) {
+      allocatorSelfType = F.mapTypeIntoContext(
+        fd->getDeclContext()->getSelfInterfaceType());
+    }
   }
 
   // Set up the throw destination if necessary.
@@ -2182,9 +2236,12 @@ void SILGenFunction::emitForeignToNativeThunk(SILDeclRef thunk) {
         getParameterTypes(nativeCI.LoweredType.getParams(), hasSelfParam);
 
       for (unsigned nativeParamIndex : indices(params)) {
+        // Adjust the parameter if we inserted an implicit isolated parameter.
+        unsigned nativeFnTyParamIndex = nativeParamIndex + hasImplicitIsolatedParameter;
+
         // Bring the parameter to +1.
         auto paramValue = params[nativeParamIndex];
-        auto thunkParam = nativeFnTy->getParameters()[nativeParamIndex];
+        auto thunkParam = nativeFnTy->getParameters()[nativeFnTyParamIndex];
         // TODO: Could avoid a retain if the bridged parameter is also +0 and
         // doesn't require a bridging conversion.
         ManagedValue param;
diff --git a/lib/SILGen/SILGenBuilder.cpp b/lib/SILGen/SILGenBuilder.cpp
index 2ae3d34cd140d..ac7e831c0bcc3 100644
--- a/lib/SILGen/SILGenBuilder.cpp
+++ b/lib/SILGen/SILGenBuilder.cpp
@@ -307,7 +307,7 @@ ManagedValue SILGenBuilder::createTupleExtract(SILLocation loc,
 
 ManagedValue SILGenBuilder::createLoadBorrow(SILLocation loc,
                                              ManagedValue base) {
-  if (SGF.getTypeLowering(base.getType()).isTrivial()) {
+  if (SGF.getTypeProperties(base.getType()).isTrivial()) {
     auto *i = createLoad(loc, base.getValue(), LoadOwnershipQualifier::Trivial);
     return ManagedValue::forBorrowedRValue(i);
   }
@@ -318,7 +318,7 @@ ManagedValue SILGenBuilder::createLoadBorrow(SILLocation loc,
 
 ManagedValue SILGenBuilder::createFormalAccessLoadBorrow(SILLocation loc,
                                                          ManagedValue base) {
-  if (SGF.getTypeLowering(base.getType()).isTrivial()) {
+  if (SGF.getTypeProperties(base.getType()).isTrivial()) {
     auto *i = createLoad(loc, base.getValue(), LoadOwnershipQualifier::Trivial);
     return ManagedValue::forBorrowedRValue(i);
   }
@@ -331,7 +331,7 @@ ManagedValue SILGenBuilder::createFormalAccessLoadBorrow(SILLocation loc,
 
 ManagedValue SILGenBuilder::createFormalAccessLoadTake(SILLocation loc,
                                                        ManagedValue base) {
-  if (SGF.getTypeLowering(base.getType()).isTrivial()) {
+  if (SGF.getTypeProperties(base.getType()).isTrivial()) {
     auto *i = createLoad(loc, base.getValue(), LoadOwnershipQualifier::Trivial);
     return ManagedValue::forObjectRValueWithoutOwnership(i);
   }
@@ -343,7 +343,7 @@ ManagedValue SILGenBuilder::createFormalAccessLoadTake(SILLocation loc,
 
 ManagedValue SILGenBuilder::createFormalAccessLoadCopy(SILLocation loc,
                                                        ManagedValue base) {
-  if (SGF.getTypeLowering(base.getType()).isTrivial()) {
+  if (SGF.getTypeProperties(base.getType()).isTrivial()) {
     auto *i = createLoad(loc, base.getValue(), LoadOwnershipQualifier::Trivial);
     return ManagedValue::forObjectRValueWithoutOwnership(i);
   }
@@ -492,9 +492,9 @@ ManagedValue SILGenBuilder::createLoadTake(SILLocation loc, ManagedValue v,
 ManagedValue SILGenBuilder::createLoadTrivial(SILLocation loc,
                                               ManagedValue addr) {
 #ifndef NDEBUG
-  auto &lowering = SGF.getTypeLowering(addr.getType());
-  assert(lowering.isTrivial());
-  assert((!lowering.isAddressOnly() || !SGF.silConv.useLoweredAddresses()) &&
+  auto props = SGF.getTypeProperties(addr.getType());
+  assert(props.isTrivial());
+  assert((!props.isAddressOnly() || !SGF.silConv.useLoweredAddresses()) &&
          "cannot load an unloadable type");
   assert(!addr.hasCleanup());
 #endif
@@ -537,6 +537,10 @@ static ManagedValue createInputFunctionArgument(
       isNoImplicitCopy |= pd->getSpecifier() == ParamSpecifier::Borrowing;
       isNoImplicitCopy |= pd->getSpecifier() == ParamSpecifier::Consuming;
     }
+
+    // ManualOwnership checks everything for implicit copies already.
+    if (B.hasManualOwnershipAttr())
+      isNoImplicitCopy = false;
   }
   if (isNoImplicitCopy)
     arg->setNoImplicitCopy(isNoImplicitCopy);
@@ -625,10 +629,10 @@ ManagedValue SILGenBuilder::createEnum(SILLocation loc, ManagedValue payload,
 }
 
 ManagedValue SILGenBuilder::createUnconditionalCheckedCast(
-    SILLocation loc, CastingIsolatedConformances isolatedConformances,
+    SILLocation loc, CheckedCastInstOptions options,
     ManagedValue op, SILType destLoweredTy, CanType destFormalTy) {
   SILValue result =
-      createUnconditionalCheckedCast(loc, isolatedConformances,
+      createUnconditionalCheckedCast(loc, options,
                                      op.forward(SGF),
                                      destLoweredTy, destFormalTy);
   return SGF.emitManagedRValueWithCleanup(result);
@@ -636,7 +640,7 @@ ManagedValue SILGenBuilder::createUnconditionalCheckedCast(
 
 void SILGenBuilder::createCheckedCastBranch(
     SILLocation loc, bool isExact,
-    CastingIsolatedConformances isolatedConformances,
+    CheckedCastInstOptions options,
     ManagedValue op,
     CanType sourceFormalTy,
     SILType destLoweredTy,
@@ -650,7 +654,7 @@ void SILGenBuilder::createCheckedCastBranch(
                                          destFormalTy)) {
     op = op.ensurePlusOne(SGF, loc);
   }
-  createCheckedCastBranch(loc, isExact, isolatedConformances,
+  createCheckedCastBranch(loc, isExact, options,
                           op.forward(SGF), sourceFormalTy,
                           destLoweredTy, destFormalTy, trueBlock, falseBlock,
                           Target1Count, Target2Count);
@@ -666,9 +670,9 @@ ManagedValue SILGenBuilder::createUpcast(SILLocation loc, ManagedValue original,
 ManagedValue SILGenBuilder::createOptionalSome(SILLocation loc,
                                                ManagedValue arg) {
   CleanupCloner cloner(*this, arg);
-  auto &argTL = SGF.getTypeLowering(arg.getType());
+  auto argProps = SGF.getTypeProperties(arg.getType());
   SILType optionalType = SILType::getOptionalType(arg.getType());
-  if (argTL.isLoadable() || !SGF.silConv.useLoweredAddresses()) {
+  if (argProps.isLoadable() || !SGF.silConv.useLoweredAddresses()) {
     SILValue someValue =
         createOptionalSome(loc, arg.forward(SGF), optionalType);
     return cloner.clone(someValue);
diff --git a/lib/SILGen/SILGenBuilder.h b/lib/SILGen/SILGenBuilder.h
index db38a03dc6d16..2a296a82a33af 100644
--- a/lib/SILGen/SILGenBuilder.h
+++ b/lib/SILGen/SILGenBuilder.h
@@ -309,14 +309,14 @@ class SILGenBuilder : public SILBuilder {
   using SILBuilder::createUnconditionalCheckedCast;
   ManagedValue createUnconditionalCheckedCast(
       SILLocation loc,
-      CastingIsolatedConformances isolatedConformances,
+      CheckedCastInstOptions options,
       ManagedValue op,
       SILType destLoweredTy,
       CanType destFormalTy);
 
   using SILBuilder::createCheckedCastBranch;
   void createCheckedCastBranch(SILLocation loc, bool isExact,
-                               CastingIsolatedConformances isolatedConformances,
+                               CheckedCastInstOptions options,
                                ManagedValue op,
                                CanType sourceFormalTy,
                                SILType destLoweredTy,
diff --git a/lib/SILGen/SILGenBuiltin.cpp b/lib/SILGen/SILGenBuiltin.cpp
index a5456dca65ce7..02dccf20c8e59 100644
--- a/lib/SILGen/SILGenBuiltin.cpp
+++ b/lib/SILGen/SILGenBuiltin.cpp
@@ -1667,8 +1667,7 @@ static ManagedValue emitCreateAsyncTask(SILGenFunction &SGF, SILLocation loc,
             .build();
 
     auto genericSig = subs.getGenericSignature().getCanonicalSignature();
-    auto genericResult = GenericTypeParamType::getType(/*depth*/ 0, /*index*/ 0,
-                                                       SGF.getASTContext());
+    auto genericResult = SGF.getASTContext().TheSelfType;
 
     // <T> () async throws -> T
     CanType functionTy =
@@ -2130,7 +2129,8 @@ static ManagedValue emitBuiltinEmplace(SILGenFunction &SGF,
                                              resultASTTy);
   bool didEmitInto;
   Initialization *dest;
-  std::unique_ptr<Initialization> destOwner;
+  TemporaryInitialization *destTemporary = nullptr;
+  InitializationPtr destOwner;
   
   // Use the context destination if available.
   if (C.getEmitInto()
@@ -2139,17 +2139,20 @@ static ManagedValue emitBuiltinEmplace(SILGenFunction &SGF,
     dest = C.getEmitInto();
   } else {
     didEmitInto = false;
-    destOwner = SGF.emitTemporary(loc, loweredBufferTy);
-    dest = destOwner.get();
+    auto destTempOwner = SGF.emitTemporary(loc, loweredBufferTy);
+    dest = destTemporary = destTempOwner.get();
+    destOwner = std::move(destTempOwner);
   }
   
   auto buffer = dest->getAddressForInPlaceInitialization(SGF, loc);
   
-  // Zero-initialize the buffer.
-  // Aside from providing a modicum of predictability if the memory isn't
-  // actually initialized, this also serves to communicate to DI that the memory
+  // Mark the buffer as initializedto communicate to DI that the memory
   // is considered initialized from this point.
-  SGF.B.createZeroInitAddr(loc, buffer);
+  auto markInit = getBuiltinValueDecl(Ctx, Ctx.getIdentifier("prepareInitialization"));
+  SGF.B.createBuiltin(loc, markInit->getBaseIdentifier(),
+                       SILType::getEmptyTupleType(Ctx),
+                       SubstitutionMap(),
+                       buffer);
 
   SILValue bufferPtr = SGF.B.createAddressToPointer(loc, buffer,
         SILType::getPrimitiveObjectType(SGF.getASTContext().TheRawPointerType),
@@ -2168,6 +2171,13 @@ static ManagedValue emitBuiltinEmplace(SILGenFunction &SGF,
     {
       SGF.B.emitBlock(errorBB);
 
+      // When the closure throws an error, it needs to clean up the buffer. This
+      // means that the buffer is uninitialized at this point.
+      // We need an `end_lifetime` so that the move-only checker doesn't insert
+      // a wrong `destroy_addr` because it thinks that the buffer is initialized
+      // here.
+      SGF.B.createEndLifetime(loc, buffer);
+
       SGF.Cleanups.emitCleanupsForReturn(CleanupLocation(loc), IsForUnwind);
 
       SGF.B.createThrowAddr(loc);
@@ -2187,16 +2197,19 @@ static ManagedValue emitBuiltinEmplace(SILGenFunction &SGF,
     return ManagedValue::forInContext();
   }
   
+  assert(destTemporary
+         && "didn't emit into context but also didn't emit into temporary?");
+  auto result = destTemporary->getManagedAddress();
   auto resultTy = SGF.getLoweredType(subs.getReplacementTypes()[0]);
   
   // If the result is naturally address-only, then we can adopt the stack slot
   // as the value directly.
   if (resultTy == loweredBufferTy.getLoweredType().getAddressType()) {
-    return SGF.emitManagedRValueWithCleanup(buffer);
+    return result;
   }
   
   // If the result is loadable, load it.
-  return SGF.B.createLoadTake(loc, ManagedValue::forLValue(buffer));
+  return SGF.B.createLoadTake(loc, result);
 }
 
 std::optional<SpecializedEmitter>
diff --git a/lib/SILGen/SILGenConcurrency.cpp b/lib/SILGen/SILGenConcurrency.cpp
index 9275dfa988749..64455af576313 100644
--- a/lib/SILGen/SILGenConcurrency.cpp
+++ b/lib/SILGen/SILGenConcurrency.cpp
@@ -15,7 +15,7 @@
 #include "RValue.h"
 #include "Scope.h"
 #include "swift/AST/ASTContext.h"
-#include "swift/AST/AvailabilityInference.h"
+#include "swift/AST/AvailabilityContext.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/DistributedDecl.h"
 #include "swift/AST/ProtocolConformance.h"
@@ -75,7 +75,7 @@ setExpectedExecutorForParameterIsolation(SILGenFunction &SGF,
   // argument.
   if (actorIsolation.getKind() == ActorIsolation::CallerIsolationInheriting) {
     auto *isolatedArg = SGF.F.maybeGetIsolatedArgument();
-    assert(isolatedArg &&
+    ASSERT(isolatedArg &&
            "Caller Isolation Inheriting without isolated parameter");
     ManagedValue isolatedMV;
     if (isolatedArg->getOwnershipKind() == OwnershipKind::Guaranteed) {
@@ -136,7 +136,8 @@ void SILGenFunction::emitExpectedExecutorProlog() {
   // Defer bodies are always called synchronously within their enclosing
   // function, so the check is unnecessary; in addition, we cannot
   // necessarily perform the check because the defer may not have
-  // captured the isolated parameter of the enclosing function.
+  // captured the isolated parameter of the enclosing function, and
+  // forcing a capture would cause DI problems in actor initializers.
   bool wantDataRaceChecks = [&] {
     if (F.isAsync() || F.isDefer())
       return false;
@@ -155,7 +156,7 @@ void SILGenFunction::emitExpectedExecutorProlog() {
   }();
 
   // FIXME: Avoid loading and checking the expected executor if concurrency is
-  // unavailable. This is specifically relevant for MainActor isolated contexts,
+  // unavailable. This is specifically relevant for MainActor-isolated contexts,
   // which are allowed to be available on OSes where concurrency is not
   // available. rdar://106827064
 
@@ -189,13 +190,14 @@ void SILGenFunction::emitExpectedExecutorProlog() {
     }
 
     case ActorIsolation::CallerIsolationInheriting:
-      assert(F.isAsync());
+      assert(F.isAsync() || F.isDefer());
       setExpectedExecutorForParameterIsolation(*this, actorIsolation);
       break;
 
     case ActorIsolation::GlobalActor:
       if (F.isAsync() || wantDataRaceChecks) {
-        setExpectedExecutorForGlobalActor(*this, actorIsolation.getGlobalActor());
+        auto globalActorType = F.mapTypeIntoContext(actorIsolation.getGlobalActor());
+        setExpectedExecutorForGlobalActor(*this, globalActorType);
       }
       break;
     }
@@ -206,10 +208,14 @@ void SILGenFunction::emitExpectedExecutorProlog() {
     switch (actorIsolation.getKind()) {
     case ActorIsolation::Unspecified:
     case ActorIsolation::Nonisolated:
-    case ActorIsolation::CallerIsolationInheriting:
     case ActorIsolation::NonisolatedUnsafe:
       break;
 
+    case ActorIsolation::CallerIsolationInheriting:
+      assert(F.isAsync());
+      setExpectedExecutorForParameterIsolation(*this, actorIsolation);
+      break;
+
     case ActorIsolation::Erased:
       llvm_unreachable("closure cannot have erased isolation");
 
@@ -222,7 +228,8 @@ void SILGenFunction::emitExpectedExecutorProlog() {
 
     case ActorIsolation::GlobalActor:
       if (wantExecutor) {
-        setExpectedExecutorForGlobalActor(*this, actorIsolation.getGlobalActor());
+        auto globalActorType = F.mapTypeIntoContext(actorIsolation.getGlobalActor());
+        setExpectedExecutorForGlobalActor(*this, globalActorType);
         break;
       }
     }
@@ -248,7 +255,7 @@ void SILGenFunction::emitExpectedExecutorProlog() {
           RegularLocation::getDebugOnlyLocation(F.getLocation(), getModule()),
           executor,
           /*mandatory*/ false);
-    } else {
+    } else if (wantDataRaceChecks) {
       // For a synchronous function, check that we're on the same executor.
       // Note: if we "know" that the code is completely Sendable-safe, this
       // is unnecessary. The type checker will need to make this determination.
@@ -564,14 +571,15 @@ SILGenFunction::emitFunctionTypeIsolation(SILLocation loc,
 
   // Emit nonisolated by simply emitting Optional.none in the result type.
   case FunctionTypeIsolation::Kind::NonIsolated:
-  case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+  case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
     return emitNonIsolatedIsolation(loc);
 
   // Emit global actor isolation by loading .shared from the global actor,
   // erasing it into `any Actor`, and injecting that into Optional.
-  case FunctionTypeIsolation::Kind::GlobalActor:
+  case FunctionTypeIsolation::Kind::GlobalActor: {
     return emitGlobalActorIsolation(loc,
              isolation.getGlobalActorType()->getCanonicalType());
+  }
 
   // Emit @isolated(any) isolation by loading the actor reference from the
   // function.
@@ -642,14 +650,14 @@ SILGenFunction::emitClosureIsolation(SILLocation loc, SILDeclRef constant,
   case ActorIsolation::Erased:
     llvm_unreachable("closures cannot directly have erased isolation");
 
-  case ActorIsolation::GlobalActor:
-    return emitGlobalActorIsolation(loc,
-             isolation.getGlobalActor()->getCanonicalType());
+  case ActorIsolation::GlobalActor: {
+    auto globalActorType = F.mapTypeIntoContext(isolation.getGlobalActor())
+                               ->getCanonicalType();
+    return emitGlobalActorIsolation(loc, globalActorType);
+  }
 
   case ActorIsolation::ActorInstance: {
-    // This should always be a capture.  That's not expressed super-cleanly
-    // in ActorIsolation, unfortunately.
-    assert(isolation.getActorInstanceParameter() == 0);
+    assert(isolation.isActorInstanceForCapture());
     auto capture = isolation.getActorInstance();
     assert(capture);
     return emitLoadOfCaptureIsolation(*this, loc, capture, constant, captures);
@@ -672,6 +680,35 @@ SILGenFunction::emitHopToTargetActor(SILLocation loc,
   }
 }
 
+namespace {
+
+class HopToActorCleanup : public Cleanup {
+  SILValue value;
+
+public:
+  HopToActorCleanup(SILValue value) : value(value) {}
+
+  void emit(SILGenFunction &SGF, CleanupLocation l,
+            ForUnwind_t forUnwind) override {
+    SGF.B.createHopToExecutor(l, value, false /*mandatory*/);
+  }
+
+  void dump(SILGenFunction &) const override {
+#ifndef NDEBUG
+    llvm::errs() << "HopToExecutorCleanup\n"
+                 << "State:" << getState() << "\n"
+                 << "Value:" << value << "\n";
+#endif
+  }
+};
+} // end anonymous namespace
+
+CleanupHandle SILGenFunction::emitScopedHopToTargetActor(SILLocation loc,
+                                                         SILValue actor) {
+  Cleanups.pushCleanup<HopToActorCleanup>(actor);
+  return Cleanups.getTopCleanup();
+}
+
 ExecutorBreadcrumb SILGenFunction::emitHopToTargetExecutor(
     SILLocation loc, SILValue executor) {
   // Record that we need to hop back to the current executor.
@@ -701,8 +738,10 @@ SILGenFunction::emitExecutor(SILLocation loc, ActorIsolation isolation,
     return emitLoadActorExecutor(loc, self);
   }
 
-  case ActorIsolation::GlobalActor:
-    return emitLoadGlobalActorExecutor(isolation.getGlobalActor());
+  case ActorIsolation::GlobalActor: {
+    auto globalActorType = F.mapTypeIntoContext(isolation.getGlobalActor());
+    return emitLoadGlobalActorExecutor(globalActorType);
+  }
   }
   llvm_unreachable("covered switch");
 }
@@ -739,9 +778,9 @@ static bool isCheckExpectedExecutorIntrinsicAvailable(SILGenModule &SGM) {
   // in main-actor context.
   auto &C = checkExecutor->getASTContext();
   if (!C.LangOpts.DisableAvailabilityChecking) {
-    auto deploymentAvailability = AvailabilityRange::forDeploymentTarget(C);
+    auto deploymentAvailability = AvailabilityContext::forDeploymentTarget(C);
     auto declAvailability =
-        AvailabilityInference::availableRange(checkExecutor);
+        AvailabilityContext::forDeclSignature(checkExecutor);
     return deploymentAvailability.isContainedIn(declAvailability);
   }
 
diff --git a/lib/SILGen/SILGenConstructor.cpp b/lib/SILGen/SILGenConstructor.cpp
index 5c0586bd1fc8e..87fcaf8160e4f 100644
--- a/lib/SILGen/SILGenConstructor.cpp
+++ b/lib/SILGen/SILGenConstructor.cpp
@@ -15,6 +15,7 @@
 #include "ExecutorBreadcrumb.h"
 #include "Initialization.h"
 #include "LValue.h"
+#include "ManagedValue.h"
 #include "RValue.h"
 #include "SILGenFunction.h"
 #include "SILGenFunctionBuilder.h"
@@ -29,7 +30,9 @@
 #include "swift/Basic/Generators.h"
 #include "swift/SIL/SILArgument.h"
 #include "swift/SIL/SILInstruction.h"
+#include "swift/SIL/SILLocation.h"
 #include "swift/SIL/SILUndef.h"
+#include "swift/SIL/SILValue.h"
 #include "swift/SIL/TypeLowering.h"
 #include <map>
 
@@ -82,13 +85,14 @@ class LoweredParamsInContextGenerator {
 
 } // end anonymous namespace
 
-static ManagedValue emitManagedParameter(SILGenFunction &SGF,
-                                         SILValue value, bool isOwned) {
+static ManagedValue emitManagedParameter(SILGenFunction &SGF, SILValue value,
+                                         bool isOwned, SILLocation loc) {
   if (isOwned) {
     return SGF.emitManagedRValueWithCleanup(value);
-  } else {
-    return ManagedValue::forBorrowedRValue(value);
   }
+  if (value->getOwnershipKind() == OwnershipKind::Unowned)
+    return ManagedValue::forUnownedObjectValue(value).ensurePlusOne(SGF, loc);
+  return ManagedValue::forBorrowedRValue(value);
 }
 
 static SILValue emitConstructorMetatypeArg(SILGenFunction &SGF,
@@ -216,7 +220,8 @@ static RValue emitImplicitValueConstructorArg(SILGenFunction &SGF,
                                               [&](Initialization *eltInit) {
         auto eltAddr =
           SGF.B.createPackElementGet(loc, packIndex, arg, eltTy);
-        ManagedValue eltMV = emitManagedParameter(SGF, eltAddr, argIsConsumed);
+        ManagedValue eltMV =
+            emitManagedParameter(SGF, eltAddr, argIsConsumed, loc);
         eltMV = SGF.B.createLoadIfLoadable(loc, eltMV);
         eltInit->copyOrInitValueInto(SGF, loc, eltMV, argIsConsumed);
         eltInit->finishInitialization(SGF);
@@ -226,7 +231,7 @@ static RValue emitImplicitValueConstructorArg(SILGenFunction &SGF,
     return RValue::forInContext();
   }
 
-  ManagedValue mvArg = emitManagedParameter(SGF, arg, argIsConsumed);
+  ManagedValue mvArg = emitManagedParameter(SGF, arg, argIsConsumed, loc);
 
   // This can happen if the value is resilient in the calling convention
   // but not resilient locally.
@@ -595,7 +600,7 @@ static bool ctorHopsInjectedByDefiniteInit(ConstructorDecl *ctor,
   // must be self-isolated
   switch (isolation) {
   case ActorIsolation::ActorInstance:
-    return isolation.getActorInstanceParameter() == 0;
+    return isolation.isActorInstanceForSelfParameter();
 
   case ActorIsolation::Erased:
     llvm_unreachable("constructor cannot have erased isolation");
@@ -738,8 +743,13 @@ void SILGenFunction::emitValueConstructor(ConstructorDecl *ctor) {
     // move only structs are non-trivial, so we need to handle this here.
     if (nominal->getAttrs().hasAttribute<RawLayoutAttr>()) {
       // Raw memory is not directly decomposable, but we still want to mark
-      // it as initialized. Use a zero initializer.
-      B.createZeroInitAddr(ctor, selfLV.getLValueAddress());
+      // it as initialized.
+      auto prepInit = getBuiltinValueDecl(getASTContext(),
+                getASTContext().getIdentifier("prepareInitialization"));
+      B.createBuiltin(ctor, prepInit->getBaseIdentifier(),
+                           SILType::getEmptyTupleType(getASTContext()),
+                           SubstitutionMap(),
+                           selfLV.getLValueAddress());
     } else if (isa<StructDecl>(nominal)
                && lowering.getLoweredType().isMoveOnly()
                && nominal->getStoredProperties().empty()) {
@@ -853,7 +863,7 @@ void SILGenFunction::emitEnumConstructor(EnumElementDecl *element) {
   Loc.markAutoGenerated();
 
   // Emit the indirect return slot.
-  std::unique_ptr<Initialization> dest;
+  InitializationPtr dest;
   if (enumTI.isAddressOnly() && silConv.useLoweredAddresses()) {
     auto &AC = getASTContext();
     auto VD = new (AC) ParamDecl(SourceLoc(), SourceLoc(),
@@ -865,8 +875,7 @@ void SILGenFunction::emitEnumConstructor(EnumElementDecl *element) {
     VD->setInterfaceType(enumIfaceTy);
     auto resultSlot =
         F.begin()->createFunctionArgument(enumTI.getLoweredType(), VD);
-    dest = std::unique_ptr<Initialization>(
-        new KnownAddressInitialization(resultSlot));
+    dest.reset(new KnownAddressInitialization(resultSlot));
   }
 
   Scope scope(Cleanups, CleanupLoc);
@@ -947,6 +956,15 @@ void SILGenFunction::emitClassConstructorAllocator(ConstructorDecl *ctor) {
     args.push_back(arg);
   }
 
+  if (F.isNonisolatedNonsending()) {
+    auto paramTy = F.mapTypeIntoContext(
+        SILType::getOpaqueIsolationType(F.getASTContext()));
+    auto inContextParamTy = F.getLoweredType(paramTy.getASTType())
+                                .getCategoryType(paramTy.getCategory());
+    SILArgument *arg = F.begin()->createFunctionArgument(inContextParamTy);
+    args.push_back(arg);
+  }
+
   bindParametersForForwarding(ctor->getParameters(), args);
 
   if (ctor->requiresUnavailableDeclABICompatibilityStubs())
@@ -1002,6 +1020,12 @@ void SILGenFunction::emitClassConstructorAllocator(ConstructorDecl *ctor) {
   }
   args.push_back(selfValue);
 
+  // For now, just do this if we have a nonisolated(nonsending) function so we
+  // do not change the semantics of non-nonisolated(nonsending) functions.
+  if (F.isNonisolatedNonsending()) {
+    emitExpectedExecutorProlog();
+  }
+
   // Call the initializer. Always use the Swift entry point, which will be a
   // bridging thunk if we're calling ObjC.
   auto initConstant = SILDeclRef(ctor, SILDeclRef::Kind::Initializer);
@@ -1114,8 +1138,15 @@ void SILGenFunction::emitClassConstructorInitializer(ConstructorDecl *ctor) {
                                    /*ignored parameters*/ 1);
 
   SILType selfTy = getLoweredLoadableType(selfDecl->getTypeInContext());
-  ManagedValue selfArg = B.createInputFunctionArgument(selfTy, selfDecl);
-  
+  // Force a lexical lifetime for the self argument of an eagerMove class' init
+  // to ensure that the body of its deinit always runs after the body of that
+  // init.
+  LifetimeAnnotation annotation = selfTy.getLifetime(F).isEagerMove()
+                                      ? LifetimeAnnotation::Lexical
+                                      : LifetimeAnnotation::None;
+  ManagedValue selfArg = B.createInputFunctionArgument(
+      selfTy, selfDecl, /*isNoImplicitCopy=*/false, annotation);
+
   // is this a designated initializer for a distributed actor?
   const bool isDesignatedDistActorInit =
     selfClassDecl->isDistributedActor() && !isDelegating;
@@ -1781,3 +1812,93 @@ void SILGenFunction::emitInitAccessor(AccessorDecl *accessor) {
 
   mergeCleanupBlocks();
 }
+
+void SILGenFunction::emitPropertyWrappedFieldInitAccessor(
+    SILDeclRef function, Expr *value, bool EmitProfilerIncrement) {
+  auto vd = cast<VarDecl>(function.getDecl());
+  auto *declContext = function.getDecl()->getInnermostDeclContext();
+  auto &ctx = getASTContext();
+
+  RegularLocation Loc(value);
+  Loc.markAutoGenerated();
+
+  auto loweredFuncDeclTy = F.getLoweredFunctionType();
+  bool isLocalContext = vd->getDeclContext()->isLocalContext();
+
+  auto createArgument = [&](VarDecl *property, SILType type,
+                            bool markUninitialized = false) {
+    auto *arg = ParamDecl::createImplicit(
+        getASTContext(), property->getBaseIdentifier(),
+        property->getBaseIdentifier(), property->getInterfaceType(),
+        declContext, ParamSpecifier::InOut);
+
+    RegularLocation loc(property);
+    loc.markAutoGenerated();
+
+    SILValue argValue = F.begin()->createFunctionArgument(type, arg);
+    if (markUninitialized) {
+      argValue = B.createMarkUninitializedOut(loc, argValue);
+    }
+
+    VarLocs[arg] = VarLoc(argValue, SILAccessEnforcement::Static);
+    InitAccessorArgumentMappings[property] = arg;
+  };
+
+  // Emit @out backing storage argument
+  auto backingStorage = vd->getPropertyWrapperBackingProperty();
+  auto backingStorageTy = getSILTypeInContext(
+      loweredFuncDeclTy->getResults()[0], loweredFuncDeclTy);
+  createArgument(backingStorage, backingStorageTy, /*markUninitialized=*/true);
+
+  // Emit `newValue` argument
+  ParameterList *params = nullptr;
+  auto newValueParam = new (ctx)
+      ParamDecl(SourceLoc(), SourceLoc(), ctx.getIdentifier("$input_value"),
+                SourceLoc(), ctx.getIdentifier("$input_value"), declContext);
+  newValueParam->setSpecifier(ParamSpecifier::LegacyOwned);
+  newValueParam->setImplicit();
+  newValueParam->setInterfaceType(
+      vd->getPropertyWrapperInitValueInterfaceType());
+  params =
+      ParameterList::create(ctx, SourceLoc(), {newValueParam}, SourceLoc());
+
+  // Nominal contexts have an extra trailing metatype argument,
+  // local contexts do not
+  auto numIgnoredParams = isLocalContext ? 0 : 1;
+  emitBasicProlog(declContext, params,
+                  /*selfParam=*/nullptr, TupleType::getEmpty(F.getASTContext()),
+                  /*errorType=*/std::nullopt,
+                  /*throwsLoc=*/SourceLoc(),
+                  /*ignored parameters*/ numIgnoredParams);
+
+  // Emit the `self` argument.
+  if (!isLocalContext)
+    emitConstructorMetatypeArg(*this, vd);
+
+  prepareEpilog(declContext, TupleType::getEmpty(F.getASTContext()),
+                std::nullopt, CleanupLocation(Loc));
+
+  // Create an opaque value binding that maps 'newValue' to the wrapper's
+  // wrappedValue AST placeholder. This makes the argument available when
+  // init(wrappedValue:) is emitted
+  std::optional<SILGenFunction::OpaqueValueRAII> opaqueValue;
+  auto initInfo = vd->getPropertyWrapperInitializerInfo();
+  auto *placeholder = initInfo.getWrappedValuePlaceholder();
+  opaqueValue.emplace(
+      *this, placeholder->getOpaqueValuePlaceholder(),
+      maybeEmitValueOfLocalVarDecl(newValueParam, AccessKind::Read));
+  assert(value == initInfo.getInitFromWrappedValue());
+
+  // Prepare InitializationPtr for the @out return buffer
+  FullExpr scope(Cleanups, CleanupLocation(value));
+  auto backingStorageArg = InitAccessorArgumentMappings[backingStorage];
+  auto backingStorageAddr = VarLocs[backingStorageArg].value;
+  InitializationPtr init(new KnownAddressInitialization(backingStorageAddr));
+
+  // Intialize the @out buffer with the given expression
+  emitExprInto(value, init.get());
+
+  // Emit epilog/cleanups
+  emitEpilog(Loc);
+  mergeCleanupBlocks();
+}
\ No newline at end of file
diff --git a/lib/SILGen/SILGenConvert.cpp b/lib/SILGen/SILGenConvert.cpp
index a3f2b8ddadd0a..b84f9bb5e5c00 100644
--- a/lib/SILGen/SILGenConvert.cpp
+++ b/lib/SILGen/SILGenConvert.cpp
@@ -1348,10 +1348,9 @@ Conversion::adjustForInitialOptionalInjection() const {
   case BridgeFromObjC:
   case BridgeResultFromObjC:
     return OptionalInjectionConversion::forInjection(
-      getBridging(getKind(), getSourceType().getOptionalObjectType(),
-                  getResultType(), getLoweredResultType(),
-                  isBridgingExplicit())
-    );
+        getBridging(getKind(), getSourceType().getOptionalObjectType(),
+                    getResultType(), getLoweredResultType(),
+                    getBridgingOriginalInputType(), isBridgingExplicit()));
   }
   llvm_unreachable("bad kind");
 }
@@ -1373,9 +1372,9 @@ Conversion::adjustForInitialOptionalConversions(CanType newSourceType) const {
   case BridgeToObjC:
   case BridgeFromObjC:
   case BridgeResultFromObjC:
-    return Conversion::getBridging(getKind(), newSourceType,
-                                   getResultType(), getLoweredResultType(),
-                                   isBridgingExplicit());
+    return Conversion::getBridging(
+        getKind(), newSourceType, getResultType(), getLoweredResultType(),
+        getBridgingOriginalInputType(), isBridgingExplicit());
   }
   llvm_unreachable("bad kind");
 }
@@ -1394,9 +1393,9 @@ std::optional<Conversion> Conversion::adjustForInitialForceValue() const {
 
   case BridgeToObjC: {
     auto sourceOptType = getSourceType().wrapInOptionalType();
-    return Conversion::getBridging(ForceAndBridgeToObjC,
-                                   sourceOptType, getResultType(),
-                                   getLoweredResultType(),
+    return Conversion::getBridging(ForceAndBridgeToObjC, sourceOptType,
+                                   getResultType(), getLoweredResultType(),
+                                   getBridgingOriginalInputType(),
                                    isBridgingExplicit());
   }
   }
diff --git a/lib/SILGen/SILGenDecl.cpp b/lib/SILGen/SILGenDecl.cpp
index cde0970462de2..65332d83edbe0 100644
--- a/lib/SILGen/SILGenDecl.cpp
+++ b/lib/SILGen/SILGenDecl.cpp
@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "Cleanup.h"
 #include "Initialization.h"
 #include "LValue.h"
 #include "RValue.h"
@@ -36,6 +37,7 @@
 #include "swift/SIL/SILType.h"
 #include "swift/SIL/TypeLowering.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <iterator>
 
 using namespace swift;
@@ -311,7 +313,7 @@ splitSingleBufferIntoTupleElements(SILGenFunction &SGF, SILLocation loc,
     if (eltCleanup.isValid())
       splitCleanups.push_back(eltCleanup);
 
-    buf.emplace_back(eltInit.release());
+    buf.emplace_back(std::move(eltInit));
   }
 
   return buf;
@@ -559,7 +561,11 @@ class LocalVariableInitialization : public SingleBufferInitialization {
 
     // If our instance type is not already @moveOnly wrapped, and it's a
     // no-implicit-copy parameter, wrap it.
-    if (!isNoImplicitCopy && !instanceType->isNoncopyable()) {
+    //
+    // Unless the function is using ManualOwnership, which checks for
+    // no-implicit-copies using a different mechanism.
+    if (!isNoImplicitCopy && instanceType->isCopyable() &&
+        !SGF.B.hasManualOwnershipAttr()) {
       if (auto *pd = dyn_cast<ParamDecl>(decl)) {
         isNoImplicitCopy = pd->isNoImplicitCopy();
         isNoImplicitCopy |= pd->getSpecifier() == ParamSpecifier::Consuming;
@@ -575,7 +581,7 @@ class LocalVariableInitialization : public SingleBufferInitialization {
       }
     }
 
-    const bool isCopyable = isNoImplicitCopy || !instanceType->isNoncopyable();
+    const bool isCopyable = isNoImplicitCopy || instanceType->isCopyable();
 
     auto boxType = SGF.SGM.Types.getContextBoxTypeForCapture(
         decl, instanceType, SGF.F.getGenericEnvironment(),
@@ -681,10 +687,19 @@ namespace {
 
 static void deallocateAddressable(SILGenFunction &SGF,
                 SILLocation l,
-                const SILGenFunction::VarLoc::AddressableBuffer::State &state) {
-  SGF.B.createEndBorrow(l, state.storeBorrow);
+                const SILGenFunction::AddressableBuffer::State &state,
+                CleanupState cleanupState) {
+  // Only delete the value if the variable was active on this path.
+  // The stack slot exists within the variable scope regardless, so always
+  // needs to be cleaned up.
+  bool active = isActiveCleanupState(cleanupState);
+  if (active) {
+    SGF.B.createEndBorrow(l, state.storeBorrow);
+  }
   SGF.B.createDeallocStack(l, state.allocStack);
-  if (state.reabstraction) {
+  if (active
+      && state.reabstraction
+      && !state.reabstraction->getType().isTrivial(SGF.F)) {
     SGF.B.createDestroyValue(l, state.reabstraction);
   }
 }
@@ -693,25 +708,33 @@ static void deallocateAddressable(SILGenFunction &SGF,
 /// binding.
 class DeallocateLocalVariableAddressableBuffer : public Cleanup {
   ValueDecl *vd;
+  CleanupHandle destroyVarHandle;
 public:
-  DeallocateLocalVariableAddressableBuffer(ValueDecl *vd) : vd(vd) {}
+  DeallocateLocalVariableAddressableBuffer(ValueDecl *vd,
+                                           CleanupHandle destroyVarHandle)
+    : vd(vd), destroyVarHandle(destroyVarHandle) {}
 
   void emit(SILGenFunction &SGF, CleanupLocation l,
             ForUnwind_t forUnwind) override {
-    auto found = SGF.VarLocs.find(vd);
-    if (found == SGF.VarLocs.end()) {
+    auto addressableBuffer = SGF.getAddressableBufferInfo(vd);
+    if (!addressableBuffer) {
       return;
     }
-    auto &loc = found->second;
     
-    if (auto &state = loc.addressableBuffer.state) {
-      // The addressable buffer was forced, so clean it up now.
-      deallocateAddressable(SGF, l, *state);
+    // Reflect the state of the variable's original cleanup.
+    CleanupState cleanupState = CleanupState::Active;
+    if (destroyVarHandle.isValid()) {
+      cleanupState = SGF.Cleanups.getCleanup(destroyVarHandle).getState();
+    }
+
+    if (auto *state = addressableBuffer->getState()) {
+      // The addressable buffer was already forced, so clean up now.
+      deallocateAddressable(SGF, l, *state, cleanupState);
     } else {
       // Remember this insert location in case we need to force the addressable
       // buffer later.
       SILInstruction *marker = SGF.B.createTuple(l, {});
-      loc.addressableBuffer.cleanupPoints.emplace_back(marker);
+      addressableBuffer->cleanupPoints.push_back({marker, cleanupState});
     }
   }
 
@@ -819,7 +842,7 @@ class LetValueInitialization : public Initialization {
 
     // If the binding has an addressable buffer forced, it should be cleaned
     // up at this scope.
-    SGF.enterLocalVariableAddressableBufferScope(vd);
+    SGF.enterLocalVariableAddressableBufferScope(vd, DestroyCleanup);
   }
 
   ~LetValueInitialization() override {
@@ -1529,7 +1552,7 @@ SILGenFunction::emitInitializationForVarDecl(VarDecl *vd, bool forceImmutable,
   // If this is a 'let' initialization for a copyable non-global, set up a let
   // binding, which stores the initialization value into VarLocs directly.
   if (forceImmutable && vd->getDeclContext()->isLocalContext() &&
-      !isa<ReferenceStorageType>(varType) && !varType->isNoncopyable())
+      !isa<ReferenceStorageType>(varType) && varType->isCopyable())
     return InitializationPtr(new LetValueInitialization(vd, *this));
 
   // If the variable has no initial value, emit a mark_uninitialized instruction
@@ -1685,8 +1708,11 @@ void SILGenFunction::visitVarDecl(VarDecl *D) {
   if (D->getAttrs().hasAttribute<CustomAttr>()) {
     // Emit the property wrapper backing initializer if necessary.
     auto initInfo = D->getPropertyWrapperInitializerInfo();
-    if (initInfo.hasInitFromWrappedValue())
+    if (initInfo.hasInitFromWrappedValue()) {
       SGM.emitPropertyWrapperBackingInitializer(D);
+      // For local context emission
+      SGM.emitPropertyWrappedFieldInitAccessor(D);
+    }
   }
 
   // Emit lazy and property wrapper backing storage.
@@ -1710,188 +1736,10 @@ void SILGenFunction::visitMacroExpansionDecl(MacroExpansionDecl *D) {
     else if (auto *stmt = node.dyn_cast<Stmt *>())
       emitStmt(stmt);
     else
-      visit(node.get<Decl *>());
+      visit(cast<Decl *>(node));
   });
 }
 
-/// Emit literals for the major, minor, and subminor components of the version
-/// and return a tuple of SILValues for them.
-static std::tuple<SILValue, SILValue, SILValue>
-emitVersionLiterals(SILLocation loc, SILGenBuilder &B, ASTContext &ctx,
-                    llvm::VersionTuple Vers) {
-  unsigned major = Vers.getMajor();
-  unsigned minor =
-      (Vers.getMinor().has_value() ? Vers.getMinor().value() : 0);
-  unsigned subminor =
-      (Vers.getSubminor().has_value() ? Vers.getSubminor().value() : 0);
-
-  SILType wordType = SILType::getBuiltinWordType(ctx);
-
-  SILValue majorValue = B.createIntegerLiteral(loc, wordType, major);
-  SILValue minorValue = B.createIntegerLiteral(loc, wordType, minor);
-  SILValue subminorValue = B.createIntegerLiteral(loc, wordType, subminor);
-
-  return std::make_tuple(majorValue, minorValue, subminorValue);
-}
-
-/// Emit a check that returns 1 if the running OS version is in
-/// the specified version range and 0 otherwise. The returned SILValue
-/// (which has type Builtin.Int1) represents the result of this check.
-SILValue SILGenFunction::emitOSVersionRangeCheck(SILLocation loc,
-                                                 const VersionRange &range,
-                                                 bool forTargetVariant) {
-  // Emit constants for the checked version range.
-  SILValue majorValue;
-  SILValue minorValue;
-  SILValue subminorValue;
-
-  std::tie(majorValue, minorValue, subminorValue) =
-      emitVersionLiterals(loc, B, getASTContext(), range.getLowerEndpoint());
-
-  // Emit call to _stdlib_isOSVersionAtLeast(major, minor, patch)
-  FuncDecl *versionQueryDecl =
-      getASTContext().getIsOSVersionAtLeastDecl();
-
-  // When targeting macCatalyst, the version number will be an iOS version number
-  // and so we call a variant of the query function that understands iOS
-  // versions.
-  if (forTargetVariant)
-    versionQueryDecl = getASTContext().getIsVariantOSVersionAtLeastDecl();
-
-  assert(versionQueryDecl);
-
-  auto silDeclRef = SILDeclRef(versionQueryDecl);
-  SILValue availabilityGTEFn = emitGlobalFunctionRef(
-      loc, silDeclRef, getConstantInfo(getTypeExpansionContext(), silDeclRef));
-
-  SILValue args[] = {majorValue, minorValue, subminorValue};
-  return B.createApply(loc, availabilityGTEFn, SubstitutionMap(), args);
-}
-
-SILValue SILGenFunction::emitOSVersionOrVariantVersionRangeCheck(
-    SILLocation loc, const VersionRange &targetRange,
-    const VersionRange &variantRange) {
-  SILValue targetMajorValue;
-  SILValue targetMinorValue;
-  SILValue targetSubminorValue;
-
-  const llvm::VersionTuple &targetVersion = targetRange.getLowerEndpoint();
-  std::tie(targetMajorValue, targetMinorValue, targetSubminorValue) =
-      emitVersionLiterals(loc, B, getASTContext(), targetVersion);
-
-  SILValue variantMajorValue;
-  SILValue variantMinorValue;
-  SILValue variantSubminorValue;
-
-  const llvm::VersionTuple &variantVersion = variantRange.getLowerEndpoint();
-  std::tie(variantMajorValue, variantMinorValue, variantSubminorValue) =
-      emitVersionLiterals(loc, B, getASTContext(), variantVersion);
-
-  FuncDecl *versionQueryDecl =
-    getASTContext().getIsOSVersionAtLeastOrVariantVersionAtLeast();
-
-  assert(versionQueryDecl);
-
-  auto silDeclRef = SILDeclRef(versionQueryDecl);
-  SILValue availabilityGTEFn = emitGlobalFunctionRef(
-      loc, silDeclRef, getConstantInfo(getTypeExpansionContext(), silDeclRef));
-
-  SILValue args[] = {
-      targetMajorValue,
-      targetMinorValue,
-      targetSubminorValue,
-      variantMajorValue,
-      variantMinorValue,
-      variantSubminorValue
-  };
-  return B.createApply(loc, availabilityGTEFn, SubstitutionMap(), args);
-}
-
-SILValue SILGenFunction::emitZipperedOSVersionRangeCheck(
-    SILLocation loc, const VersionRange &targetRange,
-    const VersionRange &variantRange) {
-  assert(getASTContext().LangOpts.TargetVariant);
-
-  VersionRange OSVersion = targetRange;
-  VersionRange VariantOSVersion = variantRange;
-
-  // We're building zippered, so we need to pass both macOS and iOS
-  // versions to the runtime version range check. At run time
-  // that check will determine what kind of process this code is loaded
-  // into. In a macOS process it will use the macOS version; in an
-  // macCatalyst process it will use the iOS version.
-  llvm::Triple VariantTriple = *getASTContext().LangOpts.TargetVariant;
-  llvm::Triple TargetTriple = getASTContext().LangOpts.Target;
-
-  // From perspective of the driver and most of the frontend,
-  // -target and -target-variant are symmetric. That is, the user
-  // can pass either:
-  //    -target x86_64-apple-macosx10.15 \
-  //    -target-variant x86_64-apple-ios13.1-macabi
-  // or:
-  //    -target x86_64-apple-ios13.1-macabi \
-  //    -target-variant x86_64-apple-macosx10.15
-  //
-  // However, the runtime availability-checking entry points need
-  // to compare against an actual running OS version and so can't be
-  // symmetric. Here we standardize on "target" means macOS version
-  // and "targetVariant" means iOS version.
-  if (tripleIsMacCatalystEnvironment(TargetTriple)) {
-    assert(VariantTriple.isMacOSX());
-    // Normalize so that "variant" always means iOS version.
-    std::swap(OSVersion, VariantOSVersion);
-    std::swap(TargetTriple, VariantTriple);
-  }
-
-  // If there is no check for either the target platform
-  // or the target-variant platform then the condition is
-  // trivially true.
-  if (OSVersion.isAll() && VariantOSVersion.isAll()) {
-    SILType i1 = SILType::getBuiltinIntegerType(1, getASTContext());
-    return B.createIntegerLiteral(loc, i1, true);
-  }
-
-  // The variant-only availability-checking entrypoint is not part
-  // of the Swift 5.0 ABI. It is only available in macOS 10.15 and above.
-  bool isVariantEntrypointAvailable = !TargetTriple.isMacOSXVersionLT(10, 15);
-
-  // If there is no check for the target but there is for the
-  // variant, then we only need to emit code for the variant check.
-  if (isVariantEntrypointAvailable && OSVersion.isAll() &&
-      !VariantOSVersion.isAll())
-    return emitOSVersionRangeCheck(loc, VariantOSVersion,
-                                   /*forVariant*/ true);
-
-  // Similarly, if there is a check for the target but not for the
-  // target variant then we only to emit code for the target check.
-  if (!OSVersion.isAll() && VariantOSVersion.isAll())
-    return emitOSVersionRangeCheck(loc, OSVersion,
-                                   /*forVariant*/ false);
-
-  if (!isVariantEntrypointAvailable ||
-      (!OSVersion.isAll() && !VariantOSVersion.isAll())) {
-
-    // If the variant-only entrypoint isn't available (as is the
-    // case pre-macOS 10.15) we need to use the zippered entrypoint
-    // (which is part of the Swift 5.0 ABI) even when the macOS version
-    // is '*' (all).
-    // In this case, use the minimum macOS deployment version from
-    // the target triple. This ensures the check always passes on macOS.
-    if (!isVariantEntrypointAvailable && OSVersion.isAll()) {
-      assert(TargetTriple.isMacOSX());
-
-      llvm::VersionTuple macosVersion;
-      TargetTriple.getMacOSXVersion(macosVersion);
-      OSVersion = VersionRange::allGTE(macosVersion);
-    }
-
-    return emitOSVersionOrVariantVersionRangeCheck(loc, OSVersion,
-                                                   VariantOSVersion);
-  }
-
-  llvm_unreachable("Unhandled zippered configuration");
-}
-
 /// Emit the boolean test and/or pattern bindings indicated by the specified
 /// stmt condition.  If the condition fails, control flow is transferred to the
 /// specified JumpDest.  The insertion point is left in the block where the
@@ -1929,6 +1777,7 @@ void SILGenFunction::emitStmtCondition(StmtCondition Cond, JumpDest FalseDest,
       auto *expr = elt.getBoolean();
       // Evaluate the condition as an i1 value (guaranteed by Sema).
       FullExpr Scope(Cleanups, CleanupLocation(expr));
+      FormalEvaluationScope EvalScope(*this);
       booleanTestValue = emitRValue(expr).forwardAsSingleValue(*this, expr);
       booleanTestValue = emitUnwrapIntegerResult(expr, booleanTestValue);
       booleanTestLoc = expr;
@@ -1936,73 +1785,7 @@ void SILGenFunction::emitStmtCondition(StmtCondition Cond, JumpDest FalseDest,
     }
 
     case StmtConditionElement::CK_Availability: {
-      // Check the running OS version to determine whether it is in the range
-      // specified by elt.
-      PoundAvailableInfo *availability = elt.getAvailability();
-
-      // Creates a boolean literal for availability conditions that have been
-      // evaluated at compile time. Automatically inverts the value for
-      // `#unavailable` queries.
-      auto createBooleanTestLiteral = [&](bool value) {
-        SILType i1 = SILType::getBuiltinIntegerType(1, getASTContext());
-        if (availability->isUnavailability())
-          value = !value;
-        return B.createIntegerLiteral(loc, i1, value);
-      };
-
-      auto versionRange = availability->getAvailableRange();
-
-      // The OS version might be left empty if availability checking was
-      // disabled. Treat it as always-true in that case.
-      assert(versionRange.has_value() ||
-             getASTContext().LangOpts.DisableAvailabilityChecking);
-
-      if (getASTContext().LangOpts.TargetVariant &&
-          !getASTContext().LangOpts.DisableAvailabilityChecking) {
-        // We're building zippered, so we need to pass both macOS and iOS
-        // versions to the the runtime version range check. At run time
-        // that check will determine what kind of process this code is loaded
-        // into. In a macOS process it will use the macOS version; in an
-        // macCatalyst process it will use the iOS version.
-
-        auto variantVersionRange =
-            elt.getAvailability()->getVariantAvailableRange();
-        assert(variantVersionRange.has_value());
-
-        if (versionRange && variantVersionRange) {
-          booleanTestValue = emitZipperedOSVersionRangeCheck(
-              loc, *versionRange, *variantVersionRange);
-        } else {
-          // Type checking did not fill in versions so as a fallback treat this
-          // condition as trivially true.
-          booleanTestValue = createBooleanTestLiteral(true);
-        }
-        break;
-      }
-
-      if (!versionRange) {
-        // Type checking did not fill in version so as a fallback treat this
-        // condition as trivially true.
-        booleanTestValue = createBooleanTestLiteral(true);
-      } else if (versionRange->isAll()) {
-        booleanTestValue = createBooleanTestLiteral(true);
-      } else if (versionRange->isEmpty()) {
-        booleanTestValue = createBooleanTestLiteral(false);
-      } else {
-        bool isMacCatalyst =
-            tripleIsMacCatalystEnvironment(getASTContext().LangOpts.Target);
-        booleanTestValue =
-            emitOSVersionRangeCheck(loc, versionRange.value(), isMacCatalyst);
-        if (availability->isUnavailability()) {
-          // If this is an unavailability check, invert the result
-          // by emitting a call to Builtin.xor_Int1(lhs, -1).
-          SILType i1 = SILType::getBuiltinIntegerType(1, getASTContext());
-          SILValue minusOne = B.createIntegerLiteral(loc, i1, -1);
-          booleanTestValue =
-            B.createBuiltinBinaryFunction(loc, "xor", i1, i1,
-                                          {booleanTestValue, minusOne});
-        }
-      }
+      booleanTestValue = emitIfAvailableQuery(loc, elt.getAvailability());
       break;
     }
 
@@ -2231,7 +2014,7 @@ InitializationPtr SILGenFunction::emitLocalVariableWithCleanup(
 }
 
 /// Create an Initialization for an uninitialized temporary.
-std::unique_ptr<TemporaryInitialization>
+TemporaryInitializationPtr
 SILGenFunction::emitTemporary(SILLocation loc, const TypeLowering &tempTL) {
   SILValue addr = emitTemporaryAllocation(loc, tempTL.getLoweredType());
   if (addr->getType().isMoveOnly())
@@ -2241,7 +2024,7 @@ SILGenFunction::emitTemporary(SILLocation loc, const TypeLowering &tempTL) {
   return useBufferAsTemporary(addr, tempTL);
 }
 
-std::unique_ptr<TemporaryInitialization>
+TemporaryInitializationPtr
 SILGenFunction::emitFormalAccessTemporary(SILLocation loc,
                                           const TypeLowering &tempTL) {
   SILValue addr = emitTemporaryAllocation(loc, tempTL.getLoweredType());
@@ -2251,16 +2034,16 @@ SILGenFunction::emitFormalAccessTemporary(SILLocation loc,
         MarkUnresolvedNonCopyableValueInst::CheckKind::ConsumableAndAssignable);
   CleanupHandle cleanup =
       enterDormantFormalAccessTemporaryCleanup(addr, loc, tempTL);
-  return std::unique_ptr<TemporaryInitialization>(
+  return TemporaryInitializationPtr(
       new TemporaryInitialization(addr, cleanup));
 }
 
 /// Create an Initialization for an uninitialized buffer.
-std::unique_ptr<TemporaryInitialization>
+TemporaryInitializationPtr
 SILGenFunction::useBufferAsTemporary(SILValue addr,
                                      const TypeLowering &tempTL) {
   CleanupHandle cleanup = enterDormantTemporaryCleanup(addr, tempTL);
-  return std::unique_ptr<TemporaryInitialization>(
+  return TemporaryInitializationPtr(
                                     new TemporaryInitialization(addr, cleanup));
 }
 
@@ -2480,24 +2263,54 @@ void SILGenFunction::destroyLocalVariable(SILLocation silLoc, VarDecl *vd) {
 }
 
 void
-SILGenFunction::enterLocalVariableAddressableBufferScope(VarDecl *decl) {
+SILGenFunction::enterLocalVariableAddressableBufferScope(VarDecl *decl,
+                                                         CleanupHandle destroyCleanup) {
   auto marker = B.createTuple(decl, {});
-  AddressableBuffers[decl] = marker;
-  Cleanups.pushCleanup<DeallocateLocalVariableAddressableBuffer>(decl);
+  AddressableBuffers[decl].insertPoint = marker;
+  Cleanups.pushCleanup<DeallocateLocalVariableAddressableBuffer>(decl, destroyCleanup);
+}
+
+static bool isFullyAbstractedLowering(SILGenFunction &SGF,
+                                      Type formalType, SILType loweredType) {
+  return SGF.getLoweredType(AbstractionPattern::getOpaque(), formalType)
+            .getASTType()
+    == loweredType.getASTType();
+}
+
+static bool isNaturallyFullyAbstractedType(SILGenFunction &SGF,
+                                           Type formalType) {
+  return isFullyAbstractedLowering(SGF, formalType, SGF.getLoweredType(formalType));
 }
 
 SILValue
-SILGenFunction::getLocalVariableAddressableBuffer(VarDecl *decl,
-                                                  SILLocation curLoc,
-                                                  ValueOwnership ownership) {
+SILGenFunction::getVariableAddressableBuffer(VarDecl *decl,
+                                             SILLocation curLoc,
+                                             ValueOwnership ownership) {
+  // For locals, we might be able to retroactively produce a local addressable
+  // representation. 
   auto foundVarLoc = VarLocs.find(decl);
   if (foundVarLoc == VarLocs.end()) {
+    // If it's not local, is it at least a global stored variable?
+    if (decl->isGlobalStorage()) {
+      // Is the global immutable?
+      if (!decl->isLet()) {
+        return SILValue();
+      }
+    
+      // Does the storage naturally have a fully abstracted representation?
+      if (!isNaturallyFullyAbstractedType(*this, decl->getTypeInContext())) {
+        return SILValue();
+      }
+
+      // We can get the stable address via the addressor.
+      return emitGlobalVariableRef(curLoc, decl, std::nullopt).getUnmanagedValue();
+    }
     return SILValue();
   }
   
   auto value = foundVarLoc->second.value;
   auto access = foundVarLoc->second.access;
-  auto *state = foundVarLoc->second.addressableBuffer.state.get();
+  auto *state = getAddressableBufferInfo(decl)->getState();
   
   SILType fullyAbstractedTy = getLoweredType(AbstractionPattern::getOpaque(),
                                      decl->getTypeInContext()->getRValueType());
@@ -2505,7 +2318,8 @@ SILGenFunction::getLocalVariableAddressableBuffer(VarDecl *decl,
   // Check whether the bound value is inherently suitable for addressability.
   // It must already be in memory and fully abstracted.
   if (value->getType().isAddress()
-      && fullyAbstractedTy.getASTType() == value->getType().getASTType()) {
+      && isFullyAbstractedLowering(*this, decl->getTypeInContext()->getRValueType(),
+                                   value->getType())) {
     SILValue address = value;
     // Begin an access if the address is mutable.
     if (access != SILAccessEnforcement::Unknown) {
@@ -2535,8 +2349,12 @@ SILGenFunction::getLocalVariableAddressableBuffer(VarDecl *decl,
   SILValue reabstraction, allocStack, storeBorrow;
   {
     SavedInsertionPointRAII save(B);
-    auto insertPoint = AddressableBuffers[decl].insertPoint;
-    B.setInsertionPoint(insertPoint);
+    auto *addressableBuffer = getAddressableBufferInfo(decl);
+
+    assert(addressableBuffer
+           && addressableBuffer->insertPoint
+           && "didn't find an insertion point for the addressable buffer");
+    B.setInsertionPoint(addressableBuffer->insertPoint);
     auto allocStackTy = fullyAbstractedTy;
     if (value->getType().isMoveOnlyWrapped()) {
       allocStackTy = allocStackTy.addingMoveOnlyWrapper();
@@ -2554,8 +2372,17 @@ SILGenFunction::getLocalVariableAddressableBuffer(VarDecl *decl,
     SavedInsertionPointRAII save(B);
     if (isa<ParamDecl>(decl)) {
       B.setInsertionPoint(allocStack->getNextInstruction());
+    } else if (auto inst = value->getDefiningInstruction()) {
+      B.setInsertionPoint(inst->getParent(), std::next(inst->getIterator()));
+    } else if (auto arg = dyn_cast<SILArgument>(value)) {
+      if (auto farg = dyn_cast<SILFunctionArgument>(value);
+          farg && farg->isClosureCapture()) {
+        B.setInsertionPoint(allocStack->getNextInstruction());
+      } else {
+        B.setInsertionPoint(arg->getParent()->begin());
+      }
     } else {
-      B.setInsertionPoint(value->getNextInstruction());
+      llvm_unreachable("unexpected value source!");
     }
     auto declarationLoc = value->getDefiningInsertionPoint()->getLoc();
     
@@ -2575,22 +2402,21 @@ SILGenFunction::getLocalVariableAddressableBuffer(VarDecl *decl,
   }
   
   // Record the addressable representation.
-  auto &addressableBuffer = VarLocs[decl].addressableBuffer;
-  addressableBuffer.state
-    = std::make_unique<VarLoc::AddressableBuffer::State>(reabstraction,
-                                                         allocStack,
-                                                         storeBorrow);
-  auto *newState = addressableBuffer.state.get();
+  auto *addressableBuffer = getAddressableBufferInfo(decl);
+  auto *newState
+    = new AddressableBuffer::State(reabstraction, allocStack, storeBorrow);
+  addressableBuffer->stateOrAlias = newState;
 
   // Emit cleanups on any paths where we previously would have cleaned up
   // the addressable representation if it had been forced earlier.
-  decltype(addressableBuffer.cleanupPoints) cleanupPoints;
-  cleanupPoints.swap(addressableBuffer.cleanupPoints);
+  decltype(addressableBuffer->cleanupPoints) cleanupPoints;
+  cleanupPoints.swap(addressableBuffer->cleanupPoints);
   
-  for (SILInstruction *cleanupPoint : cleanupPoints) {
-    SavedInsertionPointRAII insertCleanup(B, cleanupPoint);
-    deallocateAddressable(*this, cleanupPoint->getLoc(), *newState);
-    cleanupPoint->eraseFromParent();
+  for (auto &cleanupPoint : cleanupPoints) {
+    SavedInsertionPointRAII insertCleanup(B, cleanupPoint.inst);
+    deallocateAddressable(*this, cleanupPoint.inst->getLoc(), *newState,
+                          cleanupPoint.state);
+    cleanupPoint.inst->eraseFromParent();
   }
   
   return storeBorrow;
@@ -2628,8 +2454,14 @@ void BlackHoleInitialization::copyOrInitValueInto(SILGenFunction &SGF, SILLocati
   SGF.B.createIgnoredUse(loc, value.getValue());
 }
 
-SILGenFunction::VarLoc::AddressableBuffer::~AddressableBuffer() {
-  for (auto cleanupPoint : cleanupPoints) {
-    cleanupPoint->eraseFromParent();
+SILGenFunction::AddressableBuffer::~AddressableBuffer() {
+  if (insertPoint) {
+    insertPoint->eraseFromParent();
+  }
+  for (auto &cleanupPoint : cleanupPoints) {
+    cleanupPoint.inst->eraseFromParent();
+  }
+  if (auto state = stateOrAlias.dyn_cast<State*>()) {
+    delete state;
   }
 }
diff --git a/lib/SILGen/SILGenDestructor.cpp b/lib/SILGen/SILGenDestructor.cpp
index e4816d5a3dcf1..0ae90b2db278c 100644
--- a/lib/SILGen/SILGenDestructor.cpp
+++ b/lib/SILGen/SILGenDestructor.cpp
@@ -339,6 +339,17 @@ void SILGenFunction::emitDeallocatingMoveOnlyDestructor(DestructorDecl *dd) {
   B.createReturn(loc, emitEmptyTuple(loc));
 }
 
+/// Determine whether the availability for the body the given destructor predates the introduction of
+/// support for isolated deinit.
+static bool availabilityPredatesIsolatedDeinit(DestructorDecl *dd) {
+  ASTContext &ctx = dd->getASTContext();
+  if (ctx.LangOpts.DisableAvailabilityChecking)
+    return false;
+
+  auto deploymentAvailability = AvailabilityRange::forDeploymentTarget(ctx);
+  return !deploymentAvailability.isContainedIn(ctx.getIsolatedDeinitAvailability());
+}
+
 void SILGenFunction::emitIsolatingDestructor(DestructorDecl *dd) {
   MagicFunctionName = DeclName(SGM.M.getASTContext().getIdentifier("deinit"));
 
@@ -372,8 +383,15 @@ void SILGenFunction::emitIsolatingDestructor(DestructorDecl *dd) {
       executor = B.createExtractExecutor(loc, actor);
     }
 
+    // Determine whether we need the main-actor back-deployment version of
+    // this function.
+    bool useMainActorBackDeploy =
+      ai.isMainActor() && availabilityPredatesIsolatedDeinit(dd);
+
     // Get deinitOnExecutor
-    FuncDecl *swiftDeinitOnExecutorDecl = SGM.getDeinitOnExecutor();
+    FuncDecl *swiftDeinitOnExecutorDecl =
+        useMainActorBackDeploy ? SGM.getDeinitOnExecutorMainActorBackDeploy()
+                               : SGM.getDeinitOnExecutor();
     if (!swiftDeinitOnExecutorDecl) {
       dd->diagnose(diag::missing_deinit_on_executor_function);
       return;
diff --git a/lib/SILGen/SILGenDistributed.cpp b/lib/SILGen/SILGenDistributed.cpp
index 60524cf410758..d913b398fd527 100644
--- a/lib/SILGen/SILGenDistributed.cpp
+++ b/lib/SILGen/SILGenDistributed.cpp
@@ -281,8 +281,7 @@ void InitializeDistActorIdentity::dump(SILGenFunction &) const {
 
 bool SILGenFunction::shouldReplaceConstantForApplyWithDistributedThunk(
     FuncDecl *func) const {
-  auto isDistributedFuncOrAccessor =
-      func->isDistributed();
+  auto isDistributedFuncOrAccessor = func->isDistributed();
   if (auto acc = dyn_cast<AccessorDecl>(func)) {
     isDistributedFuncOrAccessor =
         acc->getStorage()->isDistributed();
diff --git a/lib/SILGen/SILGenDynamicCast.cpp b/lib/SILGen/SILGenDynamicCast.cpp
index 567cd78a7e651..31be3f15ef3cf 100644
--- a/lib/SILGen/SILGenDynamicCast.cpp
+++ b/lib/SILGen/SILGenDynamicCast.cpp
@@ -18,6 +18,7 @@
 #include "ExitableFullExpr.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/AST/ConformanceLookup.h"
+#include "swift/AST/ExistentialLayout.h"
 #include "swift/SIL/DynamicCasts.h"
 #include "swift/SIL/SILArgument.h"
 #include "swift/SIL/TypeLowering.h"
@@ -37,7 +38,7 @@ namespace {
       Scalar,
     };
     CastStrategy Strategy;
-    CastingIsolatedConformances IsolatedConformances;
+    CheckedCastInstOptions Options;
 
   public:
     CheckedCastEmitter(SILGenFunction &SGF, SILLocation loc,
@@ -45,7 +46,7 @@ namespace {
       : SGF(SGF), Loc(loc), SourceType(sourceType->getCanonicalType()),
         TargetType(targetType->getCanonicalType()),
         Strategy(computeStrategy()),
-        IsolatedConformances(computedIsolatedConformances()) {
+        Options(computedOptions()) {
     }
 
     bool isOperandIndirect() const {
@@ -58,7 +59,7 @@ namespace {
 
       SGFContext ctx;
 
-      std::unique_ptr<TemporaryInitialization> temporary;
+      TemporaryInitializationPtr temporary;
       if (isOperandIndirect()) {
         temporary = SGF.emitTemporary(Loc, origSourceTL);
         ctx = SGFContext(temporary.get());
@@ -93,7 +94,7 @@ namespace {
       if (Strategy == CastStrategy::Address) {
         SILValue resultBuffer =
           createAbstractResultBuffer(hasAbstraction, origTargetTL, ctx);
-        SGF.B.createUnconditionalCheckedCastAddr(Loc, IsolatedConformances,
+        SGF.B.createUnconditionalCheckedCastAddr(Loc, Options,
                                              operand.forward(SGF), SourceType,
                                              resultBuffer, TargetType);
         return RValue(SGF, Loc, TargetType,
@@ -102,7 +103,7 @@ namespace {
       }
 
       ManagedValue result =
-        SGF.B.createUnconditionalCheckedCast(Loc, IsolatedConformances,
+        SGF.B.createUnconditionalCheckedCast(Loc, Options,
                                              operand,
                                              origTargetTL.getLoweredType(),
                                              TargetType);
@@ -140,7 +141,7 @@ namespace {
         resultBuffer =
             createAbstractResultBuffer(hasAbstraction, origTargetTL, ctx);
         SGF.B.createCheckedCastAddrBranch(
-            Loc, IsolatedConformances, consumption, operand.forward(SGF),
+            Loc, Options, consumption, operand.forward(SGF),
             SourceType, resultBuffer, TargetType, trueBB, falseBB,
             TrueCount, FalseCount);
       } else {
@@ -157,7 +158,7 @@ namespace {
           operandValue = operandValue.borrow(SGF, Loc);
         }
         SGF.B.createCheckedCastBranch(Loc, /*exact*/ false,
-                                      IsolatedConformances, operandValue,
+                                      Options, operandValue,
                                       SourceType, origTargetTL.getLoweredType(),
                                       TargetType, trueBB, falseBB, TrueCount,
                                       FalseCount);
@@ -302,6 +303,11 @@ namespace {
       return CastStrategy::Address;
     }
 
+    CheckedCastInstOptions computedOptions() const {
+      return CheckedCastInstOptions()
+        .withIsolatedConformances(computedIsolatedConformances());
+    }
+    
     CastingIsolatedConformances computedIsolatedConformances() const {
       // Non-existential types don't carry conformances, so we always allow
       // isolated conformances.
@@ -309,7 +315,7 @@ namespace {
         return CastingIsolatedConformances::Allow;
 
       // If there is a conformance to SendableMetatype, then this existential
-      // can leave the current isolation domain. Prohibit isolated conformances.
+      // can leave the current isolation domain.
       ASTContext &ctx = TargetType->getASTContext();
       Type checkType;
       if (auto existentialMetatype = TargetType->getAs<ExistentialMetatypeType>())
@@ -317,6 +323,14 @@ namespace {
       else
         checkType = TargetType;
 
+      // If there are no non-marker protocols in the existential, there's no
+      // need to prohibit isolated conformances.
+      auto layout = checkType->getExistentialLayout();
+      if (!layout.containsNonMarkerProtocols())
+        return CastingIsolatedConformances::Allow;
+
+      // If the type conforms to SendableMetatype, prohibit isolated
+      // conformances.
       auto proto = ctx.getProtocol(KnownProtocolKind::SendableMetatype);
       if (proto && lookupConformance(checkType, proto, /*allowMissing=*/false))
         return CastingIsolatedConformances::Prohibit;
@@ -403,7 +417,7 @@ adjustForConditionalCheckedCastOperand(SILLocation loc, ManagedValue src,
   if (!hasAbstraction && (!requiresAddress || src.getType().isAddress()))
     return src;
   
-  std::unique_ptr<TemporaryInitialization> init;
+  TemporaryInitializationPtr init;
   if (requiresAddress) {
     init = SGF.emitTemporary(loc, srcAbstractTL);
 
diff --git a/lib/SILGen/SILGenEpilog.cpp b/lib/SILGen/SILGenEpilog.cpp
index 8ea4d5c98922f..e918235b74732 100644
--- a/lib/SILGen/SILGenEpilog.cpp
+++ b/lib/SILGen/SILGenEpilog.cpp
@@ -33,29 +33,44 @@ void SILGenFunction::prepareEpilog(
     // emits unreachable if there is no source level return.
     NeedsReturn = !(*directResultType)->isEqual(TupleType::getEmpty(getASTContext()));
     if (NeedsReturn) {
-      for (auto directResult : fnConv.getDirectSILResults()) {
-        SILType resultType = F.getLoweredType(F.mapTypeIntoContext(
-            fnConv.getSILType(directResult, getTypeExpansionContext())));
-        // @out tuples do not get flattened in the function's return type, but
-        // the epilog block expects (recursively) flattened arguments. Flatten
-        // the type now.
-        SmallVector<SILType, 4> worklist;
-        worklist.push_back(resultType);
-        while (!worklist.empty()) {
-          auto ty = worklist.pop_back_val();
-          if (auto tupleType = ty.getASTType()->getAs<TupleType>()) {
-            assert(!fnConv.useLoweredAddresses() &&
-                   "expanding tuple in non-opaque-values exit block?!");
-            // Push tuple elements in reverse order (resulting in later tuple
-            // elements appearing earlier in worklist) so that as the worklist
-            // is drained by popping the back, arguments are created for the
-            // earlier types first.
-            for (auto index :
-                 llvm::reverse(indices(tupleType->getElementTypes()))) {
-              worklist.push_back(ty.getTupleElementType(index));
+      if (fnConv.hasGuaranteedAddressResult() || fnConv.hasGuaranteedResult()) {
+        // Do not explode tuples for borrow/mutate accessors
+        SILType resultType =
+            F.getLoweredType(F.mapTypeIntoContext(*directResultType));
+        epilogBB->createPhiArgument(resultType, fnConv.hasGuaranteedResult()
+                                                    ? OwnershipKind::Guaranteed
+                                                    : OwnershipKind::None);
+      } else {
+        for (auto directResult : fnConv.getDirectSILResults()) {
+          SILType resultType = F.getLoweredType(F.mapTypeIntoContext(
+              fnConv.getSILType(directResult, getTypeExpansionContext())));
+          // @out tuples do not get flattened in the function's return type, but
+          // the epilog block expects (recursively) flattened arguments. Flatten
+          // the type now.
+          SmallVector<SILType, 4> worklist;
+          worklist.push_back(resultType);
+          while (!worklist.empty()) {
+            auto ty = worklist.pop_back_val();
+            if (auto tupleType = ty.getASTType()->getAs<TupleType>()) {
+              assert(!fnConv.useLoweredAddresses() &&
+                     "expanding tuple in non-opaque-values exit block?!");
+              // Push tuple elements in reverse order (resulting in later tuple
+              // elements appearing earlier in worklist) so that as the worklist
+              // is drained by popping the back, arguments are created for the
+              // earlier types first.
+              for (auto index :
+                   llvm::reverse(indices(tupleType->getElementTypes()))) {
+                worklist.push_back(ty.getTupleElementType(index));
+              }
+            } else {
+              if (fnConv.hasGuaranteedResult()) {
+                epilogBB->createPhiArgument(ty, OwnershipKind::Guaranteed);
+              } else if (fnConv.hasGuaranteedAddressResult()) {
+                epilogBB->createPhiArgument(ty, OwnershipKind::None);
+              } else {
+                epilogBB->createPhiArgument(ty, OwnershipKind::Owned);
+              }
             }
-          } else {
-            epilogBB->createPhiArgument(ty, OwnershipKind::Owned);
           }
         }
       }
@@ -83,10 +98,12 @@ void SILGenFunction::prepareEpilog(
 void SILGenFunction::prepareRethrowEpilog(
     DeclContext *dc, AbstractionPattern origErrorType, Type errorType,
     CleanupLocation cleanupLoc) {
+  ASSERT(!errorType->hasPrimaryArchetype());
 
   SILBasicBlock *rethrowBB = createBasicBlock(FunctionSection::Postmatter);
   if (!IndirectErrorResult) {
-    SILType loweredErrorType = getLoweredType(origErrorType, errorType);
+    auto errorTypeInContext = dc->mapTypeIntoContext(errorType);
+    SILType loweredErrorType = getLoweredType(origErrorType, errorTypeInContext);
     rethrowBB->createPhiArgument(loweredErrorType, OwnershipKind::Owned);
   }
 
diff --git a/lib/SILGen/SILGenExpr.cpp b/lib/SILGen/SILGenExpr.cpp
index 475ff3f0184e2..e907026f7417a 100644
--- a/lib/SILGen/SILGenExpr.cpp
+++ b/lib/SILGen/SILGenExpr.cpp
@@ -46,6 +46,7 @@
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/SourceManager.h"
 #include "swift/Basic/type_traits.h"
+#include "swift/SIL/AbstractionPattern.h"
 #include "swift/SIL/Consumption.h"
 #include "swift/SIL/DynamicCasts.h"
 #include "swift/SIL/SILArgument.h"
@@ -412,6 +413,7 @@ void SILGenFunction::emitExprInto(Expr *E, Initialization *I,
     return;
   }
 
+  FormalEvaluationScope writeback(*this);
   RValue result = emitRValue(E, SGFContext(I));
   if (result.isInContext())
     return;
@@ -480,8 +482,6 @@ namespace {
     RValue visitConditionalBridgeFromObjCExpr(ConditionalBridgeFromObjCExpr *E,
                                               SGFContext C);
     RValue visitArchetypeToSuperExpr(ArchetypeToSuperExpr *E, SGFContext C);
-    RValue visitUnresolvedTypeConversionExpr(UnresolvedTypeConversionExpr *E,
-                                             SGFContext C);
     RValue visitABISafeConversionExpr(ABISafeConversionExpr *E, SGFContext C) {
       llvm_unreachable("cannot appear in rvalue");
     }
@@ -489,14 +489,15 @@ namespace {
                                        SGFContext C);
 
     /// Helper method for handling function conversion expr to
-    /// @execution(caller). Returns an empty RValue on failure.
+    /// nonisolated(nonsending). Returns an empty RValue on failure.
     RValue emitFunctionCvtToExecutionCaller(FunctionConversionExpr *E,
                                             SGFContext C);
     /// Helper method for handling function conversion expr to a global actor
-    /// from an @execution(caller) function.
+    /// from an nonisolated(nonsending) function.
     RValue
     emitFunctionCvtFromExecutionCallerToGlobalActor(FunctionConversionExpr *E,
                                                     SGFContext C);
+
     RValue visitActorIsolationErasureExpr(ActorIsolationErasureExpr *E,
                                           SGFContext C);
     RValue visitExtractFunctionIsolationExpr(ExtractFunctionIsolationExpr *E,
@@ -749,10 +750,10 @@ tryEmitAsBridgingConversion(SILGenFunction &SGF, Expr *E, bool isExplicit,
   auto subExpr = result.SubExpr;
 
   CanType resultType = E->getType()->getCanonicalType();
-  Conversion conversion =
-    Conversion::getBridging(kind, subExpr->getType()->getCanonicalType(),
-                            resultType, SGF.getLoweredType(resultType),
-                            isExplicit);
+  Conversion conversion = Conversion::getBridging(
+      kind, subExpr->getType()->getCanonicalType(), resultType,
+      SGF.getLoweredType(resultType), AbstractionPattern(subExpr->getType()),
+      isExplicit);
 
   // Only use this special pattern for AnyErasure conversions when we're
   // emitting into a peephole.
@@ -1033,12 +1034,6 @@ RValue RValueEmitter::visitSuperRefExpr(SuperRefExpr *E, SGFContext C) {
   return RValue(SGF, E, result);
 }
 
-RValue RValueEmitter::
-visitUnresolvedTypeConversionExpr(UnresolvedTypeConversionExpr *E,
-                                  SGFContext C) {
-  llvm_unreachable("invalid code made its way into SILGen");
-}
-
 RValue RValueEmitter::visitOtherConstructorDeclRefExpr(
                                 OtherConstructorDeclRefExpr *E, SGFContext C) {
   // This should always be a child of an ApplyExpr and so will be emitted by
@@ -1294,7 +1289,7 @@ RValue RValueEmitter::visitOptionalTryExpr(OptionalTryExpr *E, SGFContext C) {
   bool isByAddress = ((usingProvidedContext || optTL.isAddressOnly()) &&
       SGF.silConv.useLoweredAddresses());
 
-  std::unique_ptr<TemporaryInitialization> optTemp;
+  TemporaryInitializationPtr optTemp;
   if (!isByAddress) {
     // If the caller produced a context for us, but we're not going
     // to use it, make sure we don't.
@@ -1500,7 +1495,7 @@ RValue RValueEmitter::visitDerivedToBaseExpr(DerivedToBaseExpr *E,
 RValue RValueEmitter::visitMetatypeConversionExpr(MetatypeConversionExpr *E,
                                                   SGFContext C) {
   SILValue metaBase =
-    SGF.emitRValueAsSingleValue(E->getSubExpr()).getUnmanagedValue();
+      SGF.emitRValueAsSingleValue(E->getSubExpr()).getUnmanagedValue();
 
   // Metatype conversion casts in the AST might not be reflected as
   // such in the SIL type system, for example, a cast from DynamicSelf.Type
@@ -1576,9 +1571,7 @@ RValueEmitter::visitConditionalBridgeFromObjCExpr(
   auto conversion = cast<FuncDecl>(conversionRef.getDecl());
   auto subs = conversionRef.getSubstitutions();
 
-  auto nativeType = Type(GenericTypeParamType::getType(/*depth*/ 0, /*index*/ 0,
-                                                       SGF.getASTContext()))
-                        .subst(subs);
+  auto nativeType = Type(SGF.getASTContext().TheSelfType).subst(subs);
 
   auto metatypeType = SGF.getLoweredType(MetatypeType::get(nativeType));
   auto metatype = ManagedValue::forObjectRValueWithoutOwnership(
@@ -1731,11 +1724,21 @@ static ManagedValue emitAnyClosureExpr(SILGenFunction &SGF, Expr *e,
   }
 }
 
-static ManagedValue convertCFunctionSignature(SILGenFunction &SGF,
-                                              FunctionConversionExpr *e,
-                                              SILType loweredResultTy,
-                                llvm::function_ref<ManagedValue ()> fnEmitter) {
-  SILType loweredDestTy = SGF.getLoweredType(e->getType());
+static ManagedValue
+convertCFunctionSignature(SILGenFunction &SGF, FunctionConversionExpr *e,
+                          SILType loweredResultTy, SGFContext C,
+                          llvm::function_ref<ManagedValue()> fnEmitter) {
+  SILType loweredDestTy;
+  auto destTy = e->getType();
+  if (const auto init = C.getAsConversion()) {
+    SILType loweredDestOptTy = init->getConversion().getLoweredResultType();
+    if (auto objTy = loweredDestOptTy.getOptionalObjectType())
+      loweredDestTy = objTy;
+    else
+      loweredDestTy = loweredDestOptTy;
+  } else
+    loweredDestTy = SGF.getLoweredType(destTy);
+
   ManagedValue result;
 
   // We're converting between C function pointer types. They better be
@@ -1770,9 +1773,9 @@ static ManagedValue convertCFunctionSignature(SILGenFunction &SGF,
   return result;
 }
 
-static
-ManagedValue emitCFunctionPointer(SILGenFunction &SGF,
-                                  FunctionConversionExpr *conversionExpr) {
+static ManagedValue emitCFunctionPointer(SILGenFunction &SGF,
+                                         FunctionConversionExpr *conversionExpr,
+                                         SGFContext C) {
   auto expr = conversionExpr->getSubExpr();
   
   // Look through base-ignored exprs to get to the function ref.
@@ -1806,20 +1809,33 @@ ManagedValue emitCFunctionPointer(SILGenFunction &SGF,
 #endif
     semanticExpr = conv->getSubExpr()->getSemanticsProvidingExpr();
   }
-  
+
+  const clang::Type *destFnType = nullptr;
+
   if (auto declRef = dyn_cast<DeclRefExpr>(semanticExpr)) {
     setLocFromConcreteDeclRef(declRef->getDeclRef());
   } else if (auto memberRef = dyn_cast<MemberRefExpr>(semanticExpr)) {
     setLocFromConcreteDeclRef(memberRef->getMember());
   } else if (isAnyClosureExpr(semanticExpr)) {
-    (void) emitAnyClosureExpr(SGF, semanticExpr,
-                              [&](AbstractClosureExpr *closure) {
-      // Emit the closure body.
-      SGF.SGM.emitClosure(closure, SGF.getClosureTypeInfo(closure));
-
-      loc = closure;
-      return ManagedValue();
-    });
+    if (auto init = C.getAsConversion()) {
+      auto conv = init->getConversion();
+      auto origParamType = conv.getBridgingOriginalInputType();
+      if (origParamType.isClangType())
+        destFnType = origParamType.getClangType();
+    }
+    (void)emitAnyClosureExpr(
+        SGF, semanticExpr, [&](AbstractClosureExpr *closure) {
+          // Emit the closure body.
+          auto functionInfo = SGF.getClosureTypeInfo(closure);
+          if (destFnType) {
+            functionInfo.OrigType =
+                AbstractionPattern(functionInfo.OrigType.getType(), destFnType);
+            SGF.SGM.Types.withClosureTypeInfo(closure, functionInfo, [] {});
+          }
+          SGF.SGM.emitClosure(closure, functionInfo);
+          loc = closure;
+          return ManagedValue::forInContext();
+        });
   } else {
     llvm_unreachable("c function pointer converted from a non-concrete decl ref");
   }
@@ -1855,13 +1871,10 @@ ManagedValue emitCFunctionPointer(SILGenFunction &SGF,
   }
 
   return convertCFunctionSignature(
-                    SGF, conversionExpr,
-                    constantInfo.getSILType(),
-                    [&]() -> ManagedValue {
-                      SILValue cRef = SGF.emitGlobalFunctionRef(expr, constant);
-                      return ManagedValue::forObjectRValueWithoutOwnership(
-                          cRef);
-                    });
+      SGF, conversionExpr, constantInfo.getSILType(), C, [&]() -> ManagedValue {
+        SILValue cRef = SGF.emitGlobalFunctionRef(expr, constant);
+        return ManagedValue::forObjectRValueWithoutOwnership(cRef);
+      });
 }
 
 // Change the representation without changing the signature or
@@ -1968,17 +1981,17 @@ RValueEmitter::emitFunctionCvtToExecutionCaller(FunctionConversionExpr *e,
   //
   // Swift 6:
   //
-  // (fn_cvt_expr type="@execution(caller) () async -> ()"
-  //   (fn_cvt_expr type="@execution(caller) @Sendable () async -> ()"
+  // (fn_cvt_expr type="nonisolated(nonsending) () async -> ()"
+  //   (fn_cvt_expr type="nonisolated(nonsending) @Sendable () async -> ()"
   //      (declref_expr type="() async -> ()"
   //
   // Swift 5:
   //
-  // (fn_cvt_expr type="@execution(caller) () async -> ()"
+  // (fn_cvt_expr type="nonisolated(nonsending) () async -> ()"
   //   (declref_expr type="() async -> ()"
   //
   // The @Sendable in Swift 6 mode is due to us not representing
-  // @execution(caller) or @Sendable in the constraint evaluator.
+  // nonisolated(nonsending) or @Sendable in the constraint evaluator.
   //
   // The reason why we need to evaluate this especially is that otherwise we
   // generate multiple
@@ -2038,7 +2051,7 @@ RValue RValueEmitter::emitFunctionCvtFromExecutionCallerToGlobalActor(
   // We are pattern matching a conversion sequence like the following:
   //
   // (fn_cvt_expr implicit type="@GlobalActor @Sendable () async -> ()
-  //    (fn_cvt_expr implicit type="@execution(caller) @Sendable () async -> ()"
+  //    (fn_cvt_expr implicit type="nonisolated(nonsending) @Sendable () async -> ()"
   //       (declref_expr type="() async -> ()"
   //
   // Where the declref referred to by the declref_expr has execution(caller)
@@ -2047,9 +2060,9 @@ RValue RValueEmitter::emitFunctionCvtFromExecutionCallerToGlobalActor(
   // fix it up later.
   //
   // What we want to emit first a direct reference to the caller as an
-  // @execution(caller) function, then we convert it to @execution(caller)
-  // @Sendable. Finally, we thunk @execution(caller) to @GlobalActor. The
-  // thunking is important so that we can ensure that @execution(caller) runs on
+  // nonisolated(nonsending) function, then we convert it to nonisolated(nonsending)
+  // @Sendable. Finally, we thunk nonisolated(nonsending) to @GlobalActor. The
+  // thunking is important so that we can ensure that nonisolated(nonsending) runs on
   // that specific @GlobalActor.
 
   CanAnyFunctionType destType =
@@ -2118,7 +2131,7 @@ RValue RValueEmitter::visitFunctionConversionExpr(FunctionConversionExpr *e,
         FunctionTypeRepresentation::CFunctionPointer) {
       // A "conversion" of a DeclRef a C function pointer is done by referencing
       // the thunk (or original C function) with the C calling convention.
-      result = emitCFunctionPointer(SGF, e);
+      result = emitCFunctionPointer(SGF, e, C);
     } else {
       // Ok, we're converting a C function pointer value to another C function
       // pointer.
@@ -2128,10 +2141,9 @@ RValue RValueEmitter::visitFunctionConversionExpr(FunctionConversionExpr *e,
 
       // Possibly bitcast the C function pointer to account for ABI-compatible
       // parameter and result type conversions
-      result = convertCFunctionSignature(SGF, e, result.getType(),
-                                         [&]() -> ManagedValue {
-                                           return result;
-                                         });
+      result =
+          convertCFunctionSignature(SGF, e, result.getType(), C,
+                                    [&]() -> ManagedValue { return result; });
     }
     return RValue(SGF, e, result);
   }
@@ -2144,6 +2156,9 @@ RValue RValueEmitter::visitFunctionConversionExpr(FunctionConversionExpr *e,
   // TODO: Move this up when we can emit closures directly with C calling
   // convention.
   auto subExpr = e->getSubExpr()->getSemanticsProvidingExpr();
+
+
+
   // Look through `as` type ascriptions that don't induce bridging too.
   while (auto subCoerce = dyn_cast<CoerceExpr>(subExpr)) {
     // Coercions that introduce bridging aren't simple type ascriptions.
@@ -2201,13 +2216,13 @@ RValue RValueEmitter::visitFunctionConversionExpr(FunctionConversionExpr *e,
     }
   }
 
-  // Check if we are converting a function to an @execution(caller) from a
-  // declref that is also @execution(caller). In such a case, this was a case
+  // Check if we are converting a function to an nonisolated(nonsending) from a
+  // declref that is also nonisolated(nonsending). In such a case, this was a case
   // that was put in by Sema. We do not need a thunk, but just need to recognize
   // this case and elide the conversion. The reason why we need to do this is
-  // that otherwise, we put in extra thunks that convert @execution(caller) to
-  // @execution(concurrent) back to @execution(caller). This is done b/c we do
-  // not represent @execution(caller) in interface types, so the actual decl ref
+  // that otherwise, we put in extra thunks that convert nonisolated(nonsending) to
+  // @concurrent back to nonisolated(nonsending). This is done b/c we do
+  // not represent nonisolated(nonsending) in interface types, so the actual decl ref
   // will be viewed as @async () -> ().
   if (destType->getIsolation().isNonIsolatedCaller()) {
     if (RValue rv = emitFunctionCvtToExecutionCaller(e, C))
@@ -2436,7 +2451,7 @@ visitConditionalCheckedCastExpr(ConditionalCheckedCastExpr *E,
   auto parent = SGF.getPGOParent(E);
   if (parent) {
     auto &Node = parent.value();
-    auto *NodeS = Node.get<Stmt *>();
+    auto *NodeS = cast<Stmt *>(Node);
     if (auto *IS = dyn_cast<IfStmt>(NodeS)) {
       trueCount = SGF.loadProfilerCount(IS->getThenStmt());
       if (auto *ElseStmt = IS->getElseStmt()) {
@@ -2500,6 +2515,17 @@ RValue RValueEmitter::visitEnumIsCaseExpr(EnumIsCaseExpr *E,
 
 RValue RValueEmitter::visitSingleValueStmtExpr(SingleValueStmtExpr *E,
                                                SGFContext C) {
+  if (E->getStmtKind() == SingleValueStmtExpr::Kind::For) {
+    auto *decl = E->getForExpressionPreamble()->ForAccumulatorDecl;
+    auto *binding = E->getForExpressionPreamble()->ForAccumulatorBinding;
+    SGF.visit(decl);
+    SGF.visit(binding);
+    SGF.emitStmt(E->getStmt());
+
+    return SGF.emitRValueForDecl(E, ConcreteDeclRef(decl), E->getType(),
+                                 AccessSemantics::Ordinary);
+  }
+
   auto emitStmt = [&]() {
     SGF.emitStmt(E->getStmt());
 
@@ -2756,8 +2782,6 @@ RValue RValueEmitter::visitMemberRefExpr(MemberRefExpr *e,
          "RValueEmitter shouldn't be called on lvalues");
   assert(isa<VarDecl>(e->getMember().getDecl()));
 
-  // Everything else should use the l-value logic.
-
   // Any writebacks for this access are tightly scoped.
   FormalEvaluationScope scope(SGF);
 
@@ -2792,6 +2816,20 @@ RValue RValueEmitter::visitSubscriptExpr(SubscriptExpr *E, SGFContext C) {
   // Any writebacks for this access are tightly scoped.
   FormalEvaluationScope scope(SGF);
 
+  // For a noncopyable resulting expression, try to borrow instead.
+  if (E->getType()->isNoncopyable()) {
+    LValue lv = SGF.emitLValue(E, SGFAccessKind::BorrowedObjectRead);
+    ManagedValue mv = SGF.emitRawProjectedLValue(E, std::move(lv));
+
+    // If we got back a borrow (aka +0) because of a coroutine read
+    // accessor, defer the end_apply to the outer evaluation scope.
+    // Otherwise, we can end any other formal accesses now.
+    if (mv.isPlusZero())
+      std::move(scope).deferPop();
+
+    return RValue(SGF, E, mv);
+  }
+
   LValue lv = SGF.emitLValue(E, SGFAccessKind::OwnedObjectRead);
   // We can't load at +0 without further analysis, since the formal access into
   // the lvalue will end immediately.
@@ -2822,12 +2860,78 @@ RValue RValueEmitter::visitDynamicSubscriptExpr(
       E->getType()->getCanonicalType(), C);
 }
 
+namespace {
+class CollectValueInitialization : public Initialization {
+  ManagedValue Value;
+
+public:
+  ManagedValue getValue() const {
+    assert(Value);
+    return Value;
+  }
+
+  void copyOrInitValueInto(SILGenFunction &SGF, SILLocation loc,
+                           ManagedValue value, bool isInit) override {
+    if (!isInit) value = value.copy(SGF, loc);
+    Value = value;
+  }
+};
+}
 
 RValue RValueEmitter::visitTupleElementExpr(TupleElementExpr *E,
                                             SGFContext C) {
   assert(!E->getType()->is<LValueType>() &&
          "RValueEmitter shouldn't be called on lvalues");
-  
+
+  auto tupleType = cast<TupleType>(E->getBase()->getType()->getCanonicalType());
+  auto projectedEltInit = C.getEmitInto();
+
+  std::optional<CollectValueInitialization> collection;
+
+  // If we have an initialization to emit into, or if we'd need to emit
+  // a tuple that contains pack expansions, make a tuple initialization
+  // of it plus some black holes.
+  if (projectedEltInit || tupleType->containsPackExpansionType()) {
+    TupleInitialization tupleInit(tupleType);
+
+    auto projectedIndex = E->getFieldNumber();
+    auto numElts = tupleType->getNumElements();
+    assert(projectedIndex < numElts);
+
+    tupleInit.SubInitializations.reserve(numElts);
+    for (auto i : range(numElts)) {
+      // Create a black-hole initialization for everything except the
+      // projected index.
+      if (i != projectedIndex) {
+        tupleInit.SubInitializations.emplace_back(new BlackHoleInitialization());
+
+      // If we have an initialization for the projected initialization,
+      // put it in the right place.
+      } else if (projectedEltInit) {
+        tupleInit.SubInitializations.emplace_back(projectedEltInit,
+                                                  PointerIsNotOwned);
+
+      // Otherwise, create the collection initialization and put it in the
+      // right place.
+      } else {
+        collection.emplace();
+        tupleInit.SubInitializations.emplace_back(&*collection,
+                                                  PointerIsNotOwned);
+      }
+    }
+
+    // Emit the expression into the initialization.
+    SGF.emitExprInto(E->getBase(), &tupleInit);
+
+    // If we had an initialization to emit into, we've done so.
+    if (projectedEltInit) {
+      return RValue::forInContext();
+    }
+
+    // Otherwise, pull out the owned value.
+    return RValue(SGF, E, collection->getValue());
+  }
+
   // If our client is ok with a +0 result, then we can compute our base as +0
   // and return its element that way.  It would not be ok to reuse the Context's
   // address buffer though, since our base value will a different type than the
@@ -2869,12 +2973,22 @@ SILGenFunction::emitApplyOfDefaultArgGenerator(SILLocation loc,
       ResultPlanBuilder::computeResultPlan(*this, calleeTypeInfo, loc, C);
   ArgumentScope argScope(*this, loc);
 
-  SmallVector<ManagedValue, 4> captures;
+  SmallVector<ManagedValue, 4> args;
+
+  // Add the implicit leading isolation argument for a
+  // nonisolated(nonsending) default argument generator.
+  if (fnType->maybeGetIsolatedParameter()) {
+    auto executor = emitExpectedExecutor(loc);
+    args.push_back(emitActorInstanceIsolation(
+                     loc, executor, executor.getType().getASTType()));
+  }
+
+  // If there are captures, those come at the end.
   emitCaptures(loc, generator, CaptureEmission::ImmediateApplication,
-               captures);
+               args);
 
   return emitApply(std::move(resultPtr), std::move(argScope), loc, fnRef, subs,
-                   captures, calleeTypeInfo, ApplyOptions(), C, std::nullopt);
+                   args, calleeTypeInfo, ApplyOptions(), C, std::nullopt);
 }
 
 RValue SILGenFunction::emitApplyOfStoredPropertyInitializer(
@@ -3399,7 +3513,11 @@ static ManagedValue emitKeyPathRValueBase(SILGenFunction &subSGF,
   
   // Upcast a class instance to the property's declared type if necessary.
   if (auto propertyClass = storage->getDeclContext()->getSelfClassDecl()) {
-    if (baseType->getClassOrBoundGenericClass() != propertyClass) {
+    if (auto selfType = baseType->getAs<DynamicSelfType>())
+      baseType = selfType->getSelfType()->getCanonicalType();
+    auto baseClass = baseType->getClassOrBoundGenericClass();
+
+    if (baseClass != propertyClass) {
       baseType = baseType->getSuperclassForDecl(propertyClass)
         ->getCanonicalType();
       paramSubstValue = subSGF.B.createUpcast(loc, paramSubstValue,
@@ -3664,8 +3782,7 @@ static SILFunction *getOrCreateKeyPathGetter(
     thunk->setGenericEnvironment(genericEnv);
   }
   SILGenFunction subSGF(SGM, *thunk, SGM.SwiftModule);
-  signature = subSGF.F.getLoweredFunctionTypeInContext(
-      subSGF.F.getTypeExpansionContext());
+  signature = subSGF.F.getLoweredFunctionTypeInContext();
   auto resultArgTy =
       subSGF.silConv.getSILType(signature->getSingleResult(), signature,
                                 subSGF.F.getTypeExpansionContext());
@@ -3762,8 +3879,7 @@ static SILFunction *getOrCreateKeyPathSetter(
     thunk->setGenericEnvironment(genericEnv);
   }
   SILGenFunction subSGF(SGM, *thunk, SGM.SwiftModule);
-  signature = subSGF.F.getLoweredFunctionTypeInContext(
-      subSGF.F.getTypeExpansionContext());
+  signature = subSGF.F.getLoweredFunctionTypeInContext();
   auto valueArgTy =
       subSGF.silConv.getSILType(signature->getParameters()[0], signature,
                                 subSGF.getTypeExpansionContext());
@@ -3815,6 +3931,7 @@ static SILFunction *getOrCreateKeyPathSetter(
   auto semantics = AccessSemantics::Ordinary;
   auto strategy = property->getAccessStrategy(semantics, AccessKind::Write,
                                               SGM.M.getSwiftModule(), expansion,
+                                              std::nullopt,
                                               /*useOldABI=*/false);
 
   LValueOptions lvOptions;
@@ -3897,8 +4014,7 @@ static SILFunction *getOrCreateKeyPathAppliedMethod(
     thunk->setGenericEnvironment(genericEnv);
   }
   SILGenFunction subSGF(SGM, *thunk, SGM.SwiftModule);
-  signature = subSGF.F.getLoweredFunctionTypeInContext(
-      subSGF.F.getTypeExpansionContext());
+  signature = subSGF.F.getLoweredFunctionTypeInContext();
   auto resultArgTy =
       subSGF.silConv.getSILType(signature->getSingleResult(), signature,
                                 subSGF.F.getTypeExpansionContext());
@@ -3987,8 +4103,7 @@ static SILFunction *getOrCreateUnappliedKeypathMethod(
     thunk->setGenericEnvironment(genericEnv);
   }
   SILGenFunction subSGF(SGM, *thunk, SGM.SwiftModule);
-  signature = subSGF.F.getLoweredFunctionTypeInContext(
-      subSGF.F.getTypeExpansionContext());
+  signature = subSGF.F.getLoweredFunctionTypeInContext();
   auto resultArgTy =
       subSGF.silConv.getSILType(signature->getSingleResult(), signature,
                                 subSGF.F.getTypeExpansionContext());
@@ -4144,17 +4259,15 @@ getOrCreateKeyPathEqualsAndHash(SILGenModule &SGM,
       
       Type formalTy = index.FormalType;
       ProtocolConformanceRef hashable = index.Hashable;
-      std::tie(formalTy, hashable)
-        = GenericEnvironment::mapConformanceRefIntoContext(genericEnv,
-                                                           formalTy,
-                                                           hashable);
-      auto formalCanTy = formalTy->getReducedType(genericSig);
+      if (genericEnv) {
+        formalTy = genericEnv->mapTypeIntoContext(formalTy);
+        hashable = hashable.subst(genericEnv->getForwardingSubstitutionMap());
+      }
+
+      auto formalCanTy = formalTy->getCanonicalType();
       
       // Get the Equatable conformance from the Hashable conformance.
-      auto equatable = hashable.getAssociatedConformance(
-          formalTy,
-          GenericTypeParamType::getType(/*depth*/ 0, /*index*/ 0, C),
-          equatableProtocol);
+      auto equatable = hashable.getAssociatedConformance(C.TheSelfType, equatableProtocol);
 
       assert(equatable.isAbstract() == hashable.isAbstract());
       if (equatable.isConcrete())
@@ -4321,9 +4434,8 @@ getOrCreateKeyPathEqualsAndHash(SILGenModule &SGM,
       auto hashable = index.Hashable;
       if (genericEnv) {
         formalTy = genericEnv->mapTypeIntoContext(formalTy)->getCanonicalType();
-        hashable = hashable.subst(index.FormalType,
-          [&](Type t) -> Type { return genericEnv->mapTypeIntoContext(t); },
-          LookUpConformanceInModule());
+        hashable = hashable.subst(
+          genericEnv->getForwardingSubstitutionMap());
       }
 
       // Set up a substitution of Self => IndexType.
@@ -4331,10 +4443,7 @@ getOrCreateKeyPathEqualsAndHash(SILGenModule &SGM,
         hashValueVar->getDeclContext()->getGenericSignatureOfContext();
       assert(hashGenericSig);
       SubstitutionMap hashableSubsMap = SubstitutionMap::get(
-          hashGenericSig,
-          [&](SubstitutableType *type) -> Type { return formalTy; },
-          [&](CanType dependentType, Type replacementType, ProtocolDecl *proto)
-              -> ProtocolConformanceRef { return hashable; });
+          hashGenericSig, formalTy, hashable);
 
       // Read the storage.
       ManagedValue base = ManagedValue::forBorrowedAddressRValue(indexAddr);
@@ -4634,7 +4743,7 @@ KeyPathPatternComponent SILGenModule::emitKeyPathComponentForDecl(
     auto strategy = storage->getAccessStrategy(
         AccessSemantics::Ordinary,
         storage->supportsMutation() ? AccessKind::ReadWrite : AccessKind::Read,
-        M.getSwiftModule(), expansion,
+        M.getSwiftModule(), expansion, std::nullopt,
         /*useOldABI=*/false);
 
     AbstractStorageDecl *externalDecl = nullptr;
@@ -4999,7 +5108,7 @@ static RValue emitInlineArrayLiteral(SILGenFunction &SGF, CollectionExpr *E,
                                      SGFContext C) {
   ArgumentScope scope(SGF, E);
 
-  auto iaTy = E->getType()->castTo<BoundGenericType>();
+  auto iaTy = E->getType()->castTo<BoundGenericStructType>();
   auto loweredIAType = SGF.getLoweredType(iaTy);
 
   // If this is an empty InlineArray literal and it's loadable, then create an
@@ -5014,9 +5123,19 @@ static RValue emitInlineArrayLiteral(SILGenFunction &SGF, CollectionExpr *E,
   auto elementType = iaTy->getGenericArgs()[1]->getCanonicalType();
   auto &eltTL = SGF.getTypeLowering(AbstractionPattern::getOpaque(), elementType);
 
+
+  auto *arrayDecl = cast<StructDecl>(iaTy->getDecl());
+  VarDecl *storageProperty = nullptr;
+  for (VarDecl *property : arrayDecl->getStoredProperties()) {
+    if ((property->getTypeInContext()->is<BuiltinFixedArrayType>())) {
+      storageProperty = property;
+      break;
+    }
+  }
+
   SILValue alloc = SGF.emitTemporaryAllocation(E, loweredIAType);
-  SILValue addr = SGF.B.createUncheckedAddrCast(E, alloc,
-                                            eltTL.getLoweredType().getAddressType());
+  SILValue storage = SGF.B.createStructElementAddr(E, alloc, storageProperty);
+  SILValue addr = SGF.B.createVectorBaseAddr(E, storage);
 
   // Cleanups for any elements that have been initialized so far.
   SmallVector<CleanupHandle, 8> cleanups;
@@ -6072,6 +6191,8 @@ RValue RValueEmitter::visitOptionalEvaluationExpr(OptionalEvaluationExpr *E,
   SmallVector<ManagedValue, 1> results;
   SGF.emitOptionalEvaluation(E, E->getType(), results, C,
     [&](SmallVectorImpl<ManagedValue> &results, SGFContext primaryC) {
+      // Generate each result in its own evaluation scope.
+      FormalEvaluationScope evalScope(SGF);
       ManagedValue result;
       if (!emitOptimizedOptionalEvaluation(SGF, E, result, primaryC)) {
         result = SGF.emitRValueAsSingleValue(E->getSubExpr(), primaryC);
@@ -6108,7 +6229,7 @@ void SILGenFunction::emitOptionalEvaluation(SILLocation loc, Type optType,
   bool isByAddress = ((usingProvidedContext || optTL.isAddressOnly()) &&
                       silConv.useLoweredAddresses());
 
-  std::unique_ptr<TemporaryInitialization> optTemp;
+  TemporaryInitializationPtr optTemp;
   if (!isByAddress) {
     // If the caller produced a context for us, but we're not going
     // to use it, make sure we don't.
@@ -6132,7 +6253,7 @@ void SILGenFunction::emitOptionalEvaluation(SILLocation loc, Type optType,
 
   // Inside of the cleanups scope, create a new initialization to
   // emit into optAddr.
-  std::unique_ptr<TemporaryInitialization> normalInit;
+  TemporaryInitializationPtr normalInit;
   if (isByAddress) {
     normalInit = useBufferAsTemporary(optAddr, optTL);
   }
@@ -6405,7 +6526,7 @@ RValue RValueEmitter::emitForceValue(ForceValueExpr *loc, Expr *E,
 void SILGenFunction::emitOpenExistentialExprImpl(
        OpenExistentialExpr *E,
        llvm::function_ref<void(Expr *)> emitSubExpr) {
-  assert(isInFormalEvaluationScope());
+  ASSERT(isInFormalEvaluationScope());
 
   // Emit the existential value.
   if (E->getExistentialValue()->getType()->is<LValueType>()) {
@@ -6440,7 +6561,14 @@ RValue RValueEmitter::visitOpenExistentialExpr(OpenExistentialExpr *E,
     return RValue(SGF, E, *result);
   }
 
-  FormalEvaluationScope writebackScope(SGF);
+  // Introduce a fresh, nested evaluation scope for Copyable types.
+  // This is a bit of a hack, as it should always be up to our caller
+  // to establish the right level of formal access scope, in case we
+  // formally borrow the opened existential instead of copying it.
+  std::optional<FormalEvaluationScope> scope;
+  if (!E->getType()->isNoncopyable())
+    scope.emplace(SGF);
+
   return SGF.emitOpenExistentialExpr<RValue>(E,
                                              [&](Expr *subExpr) -> RValue {
                                                return visit(subExpr, C);
@@ -6680,7 +6808,7 @@ static void diagnoseImplicitRawConversion(Type sourceTy, Type pointerTy,
   // Array conversion does not always go down the ArrayConverter
   // path. Recognize the Array source type here both for ArrayToPointer and
   // InoutToPointer cases and diagnose on the element type.
-  Type eltTy = sourceTy->isArrayType();
+  Type eltTy = sourceTy->getArrayElementType();
   if (!eltTy)
     eltTy = sourceTy;
 
@@ -7140,7 +7268,7 @@ RValue RValueEmitter::visitConsumeExpr(ConsumeExpr *E, SGFContext C) {
 
   // If we aren't loadable, then create a temporary initialization and
   // explicit_copy_addr into that.
-  std::unique_ptr<TemporaryInitialization> optTemp;
+  TemporaryInitializationPtr optTemp;
   optTemp = SGF.emitTemporary(E, SGF.getTypeLowering(subType));
   SILValue toAddr = optTemp->getAddressForInPlaceInitialization(SGF, E);
   assert(!isa<LValueType>(E->getType()->getCanonicalType()) &&
@@ -7174,11 +7302,38 @@ RValue RValueEmitter::visitCopyExpr(CopyExpr *E, SGFContext C) {
 
   if (auto *li = dyn_cast<LoadExpr>(subExpr)) {
     FormalEvaluationScope writeback(SGF);
+
+    // If we're relying on ManualOwnership for explicit-copies enforcement,
+    // avoid doing address-based emission for loadable types.
+    if (subType.isLoadableOrOpaque(SGF.F) && SGF.B.hasManualOwnershipAttr()) {
+      // Do a read on the lvalue. If we get back an address, do a load before
+      // emitting the explicit copy.
+      LValue lv =
+        SGF.emitLValue(li->getSubExpr(), SGFAccessKind::BorrowedObjectRead);
+      auto value = SGF.emitRawProjectedLValue(E, std::move(lv));
+      if (value.getType().isAddress()) {
+        // We don't have 'load [explicit_copy]' so do this instead:
+        //   %x = load [copy] %value
+        //   %y = explicit_copy_value %x
+        value = SGF.emitManagedLoadCopy(E, value.getUnmanagedValue());
+      }
+      ManagedValue copy = SGF.B.createExplicitCopyValue(E, value);
+      return RValue(SGF, {copy}, subType.getASTType());
+    }
+
     LValue lv =
         SGF.emitLValue(li->getSubExpr(), SGFAccessKind::BorrowedAddressRead);
     auto address = SGF.emitAddressOfLValue(subExpr, std::move(lv));
 
     if (subType.isLoadable(SGF.F)) {
+      // Trivial types don't undergo any lifetime analysis, so simply load
+      // the value.
+      if (subType.isTrivial(SGF.F)
+          && !address.getType().isMoveOnlyWrapped()) {
+        return RValue(SGF, {SGF.B.createLoadCopy(E, address)},
+                      subType.getASTType());
+      }
+
       // Use a formal access load borrow so this closes in the writeback scope
       // above.
       ManagedValue value = SGF.B.createFormalAccessLoadBorrow(E, address);
@@ -7210,8 +7365,10 @@ RValue RValueEmitter::visitCopyExpr(CopyExpr *E, SGFContext C) {
     return RValue(SGF, {optTemp->getManagedAddress()}, subType.getASTType());
   }
 
-  if (subType.isLoadable(SGF.F)) {
-    ManagedValue mv = SGF.emitRValue(subExpr).getAsSingleValue(SGF, subExpr);
+  if (subType.isLoadable(SGF.F) || !SGF.silConv.useLoweredAddresses()) {
+    ManagedValue mv =
+      SGF.emitRValue(subExpr, SGFContext::AllowImmediatePlusZero)
+         .getAsSingleValue(SGF, subExpr);
     if (mv.getType().isTrivial(SGF.F))
       return RValue(SGF, {mv}, subType.getASTType());
     {
@@ -7237,7 +7394,7 @@ RValue RValueEmitter::visitCopyExpr(CopyExpr *E, SGFContext C) {
 
   // If we aren't loadable, then create a temporary initialization and
   // explicit_copy_addr into that.
-  std::unique_ptr<TemporaryInitialization> optTemp;
+  TemporaryInitializationPtr optTemp;
   optTemp = SGF.emitTemporary(E, SGF.getTypeLowering(subType));
   SILValue toAddr = optTemp->getAddressForInPlaceInitialization(SGF, E);
   assert(!isa<LValueType>(E->getType()->getCanonicalType()) &&
@@ -7271,30 +7428,58 @@ RValue RValueEmitter::visitMacroExpansionExpr(MacroExpansionExpr *E,
       else if (auto *stmt = node.dyn_cast<Stmt *>())
         SGF.emitStmt(stmt);
       else
-        SGF.visit(node.get<Decl *>());
+        SGF.visit(cast<Decl *>(node));
     });
     return RValue();
   }
   return RValue();
 }
 
+/// getActorIsolationOfContext doesn't return the right isolation for
+/// initializer contexts. Fixing that is a lot of work, so just
+/// hack around it for now here.
+static ActorIsolation getRealActorIsolationOfContext(DeclContext *DC) {
+  if (auto init = dyn_cast<Initializer>(DC)) {
+    return getActorIsolation(init);
+  } else {
+    return getActorIsolationOfContext(DC);
+  }
+}
+
 RValue RValueEmitter::visitCurrentContextIsolationExpr(
     CurrentContextIsolationExpr *E, SGFContext C) {
-  // If we are in an actor initializer that is isolated to self, the
-  // current isolation is flow-sensitive; use that instead of the
-  // synthesized expression.
-  if (auto ctor = dyn_cast_or_null<ConstructorDecl>(
-          SGF.F.getDeclRef().getDecl())) {
-    auto isolation = getActorIsolation(ctor);
-    if (ctor->isDesignatedInit() &&
-        isolation == ActorIsolation::ActorInstance &&
+
+  auto isolation = getRealActorIsolationOfContext(SGF.FunctionDC);
+
+  if (isolation == ActorIsolation::CallerIsolationInheriting) {
+    auto *isolatedArg = SGF.F.maybeGetIsolatedArgument();
+    assert(isolatedArg &&
+           "Caller Isolation Inheriting without isolated parameter");
+    ManagedValue isolatedMV;
+    if (isolatedArg->getOwnershipKind() == OwnershipKind::Guaranteed) {
+      isolatedMV = ManagedValue::forBorrowedRValue(isolatedArg);
+    } else {
+      isolatedMV = ManagedValue::forUnmanagedOwnedValue(isolatedArg);
+    }
+    return RValue(SGF, E, isolatedMV);
+  }
+
+  if (isolation == ActorIsolation::ActorInstance) {
+    auto ctor = dyn_cast<ConstructorDecl>(SGF.FunctionDC);
+    if (ctor && ctor->isDesignatedInit() &&
         isolation.getActorInstance() == ctor->getImplicitSelfDecl()) {
+      // If we are in an actor initializer that is isolated to self, the
+      // current isolation is flow-sensitive; use that instead of the
+      // synthesized expression.
       auto isolationValue =
         SGF.emitFlowSensitiveSelfIsolation(E, isolation);
       return RValue(SGF, E, isolationValue);
     }
   }
 
+  // Otherwise, just trust the underlying expression. We really don't
+  // need to do this at all --- we assume we can produce the isolation
+  // value from scratch in other situations --- but whatever.
   return visit(E->getActor(), C);
 }
 
@@ -7400,9 +7585,10 @@ void SILGenFunction::emitIgnoredExpr(Expr *E) {
   // arguments.
   
   FullExpr scope(Cleanups, CleanupLocation(E));
+  FormalEvaluationScope evalScope(*this);
+
   if (E->getType()->hasLValueType()) {
     // Emit the l-value, but don't perform an access.
-    FormalEvaluationScope scope(*this);
     emitLValue(E, SGFAccessKind::IgnoredRead);
     return;
   }
@@ -7410,7 +7596,6 @@ void SILGenFunction::emitIgnoredExpr(Expr *E) {
   // If this is a load expression, we try hard not to actually do the load
   // (which could materialize a potentially expensive value with cleanups).
   if (auto *LE = dyn_cast<LoadExpr>(E)) {
-    FormalEvaluationScope scope(*this);
     LValue lv = emitLValue(LE->getSubExpr(), SGFAccessKind::IgnoredRead);
 
     // If loading from the lvalue is guaranteed to have no side effects, we
@@ -7445,7 +7630,6 @@ void SILGenFunction::emitIgnoredExpr(Expr *E) {
   // emit the precondition(s) without having to load the value.
   SmallVector<ForceValueExpr *, 4> forceValueExprs;
   if (auto *LE = findLoadThroughForceValueExprs(E, forceValueExprs)) {
-    FormalEvaluationScope scope(*this);
     LValue lv = emitLValue(LE->getSubExpr(), SGFAccessKind::IgnoredRead);
 
     ManagedValue value;
diff --git a/lib/SILGen/SILGenFunction.cpp b/lib/SILGen/SILGenFunction.cpp
index fe47d7a623cf7..e39ebbfc0b8e5 100644
--- a/lib/SILGen/SILGenFunction.cpp
+++ b/lib/SILGen/SILGenFunction.cpp
@@ -192,6 +192,8 @@ DeclName SILGenModule::getMagicFunctionName(SILDeclRef ref) {
   case SILDeclRef::Kind::StoredPropertyInitializer:
   case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
     return getMagicFunctionName(cast<VarDecl>(ref.getDecl())->getDeclContext());
+  case SILDeclRef::Kind::PropertyWrappedFieldInitAccessor:
+    return getMagicFunctionName(cast<VarDecl>(ref.getDecl())->getDeclContext());
   case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
     return getMagicFunctionName(cast<VarDecl>(ref.getDecl())->getDeclContext());
   case SILDeclRef::Kind::IVarInitializer:
@@ -334,7 +336,7 @@ static MacroInfo getMacroInfo(const GeneratedSourceInfo &Info,
       Result.ExpansionLoc = RegularLocation(expr);
       Result.Name = mangler.mangleMacroExpansion(expr);
     } else {
-      auto decl = cast<MacroExpansionDecl>(parent.get<Decl *>());
+      auto decl = cast<MacroExpansionDecl>(cast<Decl *>(parent));
       Result.ExpansionLoc = RegularLocation(decl);
       Result.Name = mangler.mangleMacroExpansion(decl);
     }
@@ -350,7 +352,7 @@ static MacroInfo getMacroInfo(const GeneratedSourceInfo &Info,
   case GeneratedSourceInfo::DeclarationMacroExpansion: 
   case GeneratedSourceInfo::CodeItemMacroExpansion: {
     auto expansion = cast<MacroExpansionDecl>(
-        ASTNode::getFromOpaqueValue(Info.astNode).get<Decl *>());
+        cast<Decl *>(ASTNode::getFromOpaqueValue(Info.astNode)));
     Result.ExpansionLoc = RegularLocation(expansion);
     Result.Name = mangler.mangleMacroExpansion(expansion);
     Result.Freestanding = true;
@@ -367,7 +369,7 @@ static MacroInfo getMacroInfo(const GeneratedSourceInfo &Info,
   case GeneratedSourceInfo::ExtensionMacroExpansion:
   case GeneratedSourceInfo::PreambleMacroExpansion:
   case GeneratedSourceInfo::BodyMacroExpansion: {
-    auto decl = ASTNode::getFromOpaqueValue(Info.astNode).get<Decl *>();
+    auto decl = cast<Decl *>(ASTNode::getFromOpaqueValue(Info.astNode));
     auto attr = Info.attachedMacroCustomAttr;
     if (auto *macroDecl = decl->getResolvedMacro(attr)) {
       Result.ExpansionLoc = RegularLocation(macroDecl);
@@ -1424,51 +1426,44 @@ void SILGenFunction::emitAsyncMainThreadStart(SILDeclRef entryPoint) {
 
   B.setInsertionPoint(entryBlock);
 
-  // If we're using a new enough deployment target, call swift_createExecutors()
-  if (ctx.LangOpts.ExecutorFactory) {
-    if (!isCreateExecutorsFunctionAvailable(SGM)) {
-      ctx.Diags.diagnose(SourceLoc(), diag::executor_factory_not_supported);
-    } else {
-      CanType factoryTy = SGM.getConfiguredExecutorFactory()->getCanonicalType();
+  // If we're using a new enough deployment target, and we can find a
+  // DefaultExecutorFactory type, call swift_createExecutors()
+  Type factoryNonCanTy = SGM.getConfiguredExecutorFactory();
 
-      if (!factoryTy) {
-        ctx.Diags.diagnose(SourceLoc(), diag::cannot_find_executor_factory_type,
-                           *ctx.LangOpts.ExecutorFactory);
-      }
+  if (isCreateExecutorsFunctionAvailable(SGM) && factoryNonCanTy) {
+    CanType factoryTy = factoryNonCanTy->getCanonicalType();
 
-      ProtocolDecl *executorFactoryProtocol
-        = ctx.getProtocol(KnownProtocolKind::ExecutorFactory);
-      auto conformance = lookupConformance(factoryTy, executorFactoryProtocol);
+    ProtocolDecl *executorFactoryProtocol
+      = ctx.getProtocol(KnownProtocolKind::ExecutorFactory);
+    auto conformance = lookupConformance(factoryTy, executorFactoryProtocol);
 
-      if (conformance.isInvalid()) {
-        // If this type doesn't conform, ignore it and use the default factory
-        SourceLoc loc = extractNearestSourceLoc(factoryTy);
+    if (conformance.isInvalid()) {
+      // If this type doesn't conform, ignore it and use the default factory
+      SourceLoc loc = extractNearestSourceLoc(factoryTy);
 
-        ctx.Diags.diagnose(loc, diag::executor_factory_must_conform,
-                           *ctx.LangOpts.ExecutorFactory);
+      ctx.Diags.diagnose(loc, diag::executor_factory_must_conform);
 
-        factoryTy = SGM.getDefaultExecutorFactory()->getCanonicalType();
-        conformance = lookupConformance(factoryTy, executorFactoryProtocol);
+      factoryTy = SGM.getDefaultExecutorFactory()->getCanonicalType();
+      conformance = lookupConformance(factoryTy, executorFactoryProtocol);
 
-        assert(!conformance.isInvalid());
-      }
+      assert(!conformance.isInvalid());
+    }
 
-      FuncDecl *createExecutorsFuncDecl = SGM.getCreateExecutors();
-      assert(createExecutorsFuncDecl
-             && "Failed to find swift_createExecutors function decl");
-      SILFunction *createExecutorsSILFunc =
-        SGM.getFunction(SILDeclRef(createExecutorsFuncDecl, SILDeclRef::Kind::Func),
+    FuncDecl *createExecutorsFuncDecl = SGM.getCreateExecutors();
+    assert(createExecutorsFuncDecl
+           && "Failed to find swift_createExecutors function decl");
+    SILFunction *createExecutorsSILFunc =
+      SGM.getFunction(SILDeclRef(createExecutorsFuncDecl, SILDeclRef::Kind::Func),
                         NotForDefinition);
-      SILValue createExecutorsFunc =
-        B.createFunctionRefFor(moduleLoc, createExecutorsSILFunc);
-      MetatypeType *factoryThickMetaTy
-        = MetatypeType::get(factoryTy, MetatypeRepresentation::Thick);
-      SILValue factorySILMetaTy
-        = B.createMetatype(moduleLoc, getLoweredType(factoryThickMetaTy));
-      auto ceSubs = SubstitutionMap::getProtocolSubstitutions(
-        conformance.getProtocol(), factoryTy, conformance);
-      B.createApply(moduleLoc, createExecutorsFunc, ceSubs, { factorySILMetaTy });
-    }
+    SILValue createExecutorsFunc =
+      B.createFunctionRefFor(moduleLoc, createExecutorsSILFunc);
+    MetatypeType *factoryThickMetaTy
+      = MetatypeType::get(factoryTy, MetatypeRepresentation::Thick);
+    SILValue factorySILMetaTy
+      = B.createMetatype(moduleLoc, getLoweredType(factoryThickMetaTy));
+    auto ceSubs = SubstitutionMap::getProtocolSubstitutions(
+      conformance.getProtocol(), factoryTy, conformance);
+    B.createApply(moduleLoc, createExecutorsFunc, ceSubs, { factorySILMetaTy });
   }
 
   auto wrapCallArgs = [this, &moduleLoc](SILValue originalValue, FuncDecl *fd,
@@ -1753,7 +1748,7 @@ void SILGenFunction::emitGeneratorFunction(
   mergeCleanupBlocks();
 }
 
-std::unique_ptr<Initialization> SILGenFunction::getSingleValueStmtInit(Expr *E) {
+InitializationPtr SILGenFunction::getSingleValueStmtInit(Expr *E) {
   if (SingleValueStmtInitStack.empty())
     return nullptr;
 
@@ -1763,7 +1758,7 @@ std::unique_ptr<Initialization> SILGenFunction::getSingleValueStmtInit(Expr *E)
     return nullptr;
   
   auto resultAddr = SingleValueStmtInitStack.back().InitializationBuffer;
-  return std::make_unique<KnownAddressInitialization>(resultAddr);
+  return make_possibly_unique<KnownAddressInitialization>(resultAddr);
 }
 
 void SILGenFunction::emitProfilerIncrement(ASTNode Node) {
@@ -1936,11 +1931,6 @@ void SILGenFunction::emitAssignOrInit(SILLocation loc, ManagedValue selfValue,
 
   auto initTy = initFRef->getType().castTo<SILFunctionType>();
 
-  // If there are substitutions we need to emit partial apply to
-  // apply substitutions to the init accessor reference type.
-  initTy = initTy->substGenericArgs(SGM.M, substitutions,
-                                    getTypeExpansionContext());
-
   // Emit partial apply with self metatype argument to produce a substituted
   // init accessor reference.
   auto selfTy = selfValue.getType().getASTType();
@@ -1954,8 +1944,9 @@ void SILGenFunction::emitAssignOrInit(SILLocation loc, ManagedValue selfValue,
     selfMetatype = B.createMetatype(loc, getLoweredType(metatypeTy));
   }
 
-  auto expectedSelfTy = initAccessor->getDeclContext()->getSelfInterfaceType()
-      .subst(substitutions);
+  auto expectedSelfTy =
+      initAccessor->getDeclContext()->getSelfInterfaceType().subst(
+          substitutions);
 
   // This should only happen in the invalid case where we attempt to initialize
   // superclass storage from a subclass initializer. However, we shouldn't
@@ -1965,6 +1956,14 @@ void SILGenFunction::emitAssignOrInit(SILLocation loc, ManagedValue selfValue,
     selfMetatype = B.createUpcast(loc, selfMetatype,
                              getLoweredType(MetatypeType::get(expectedSelfTy)));
   }
+
+  if (auto invocationSig = initTy->getInvocationGenericSignature()) {
+    if (invocationSig->areAllParamsConcrete())
+      substitutions = SubstitutionMap();
+  } else {
+    substitutions = SubstitutionMap();
+  }
+
   PartialApplyInst *initPAI =
       B.createPartialApply(loc, initFRef, substitutions, selfMetatype,
                            ParameterConvention::Direct_Guaranteed,
@@ -2011,3 +2010,17 @@ void SILGenFunction::emitAssignOrInit(SILLocation loc, ManagedValue selfValue,
                        newValue.forward(*this), initFRef, setterFRef,
                        AssignOrInitInst::Unknown);
 }
+
+SILGenFunction::AddressableBuffer *
+SILGenFunction::getAddressableBufferInfo(ValueDecl *vd) {
+  do {
+    auto &found = AddressableBuffers[vd];
+
+    if (auto orig = found.stateOrAlias
+                      .dyn_cast<VarDecl*>()) {
+      vd = orig;
+      continue;
+    }
+    return &found;
+  } while (true);
+}
diff --git a/lib/SILGen/SILGenFunction.h b/lib/SILGen/SILGenFunction.h
index 4fa83c5e326ed..3ffb39baaf3cc 100644
--- a/lib/SILGen/SILGenFunction.h
+++ b/lib/SILGen/SILGenFunction.h
@@ -27,6 +27,7 @@
 #include "swift/Basic/ProfileCounter.h"
 #include "swift/Basic/Statistic.h"
 #include "swift/SIL/SILBuilder.h"
+#include "swift/SIL/SILInstruction.h"
 #include "swift/SIL/SILType.h"
 #include "llvm/ADT/PointerIntPair.h"
 
@@ -44,6 +45,7 @@ class ConsumableManagedValue;
 class LogicalPathComponent;
 class LValue;
 class ManagedValue;
+class PathComponent;
 class PreparedArguments;
 class RValue;
 class CalleeTypeInfo;
@@ -56,6 +58,8 @@ class ExecutorBreadcrumb;
 struct LValueOptions {
   bool IsNonAccessing = false;
   bool TryAddressable = false;
+  bool ForGuaranteedReturn = false;
+  bool ForGuaranteedAddressReturn = false;
 
   /// Derive options for accessing the base of an l-value, given that
   /// applying the derived component might touch the memory.
@@ -79,6 +83,18 @@ struct LValueOptions {
     copy.TryAddressable = addressable;
     return copy;
   }
+
+  LValueOptions forGuaranteedReturn(bool value) const {
+    auto copy = *this;
+    copy.ForGuaranteedReturn = value;
+    return copy;
+  }
+
+  LValueOptions forGuaranteedAddressReturn(bool value) const {
+    auto copy = *this;
+    copy.ForGuaranteedAddressReturn = value;
+    return copy;
+  }
 };
 
 class PatternMatchContext;
@@ -476,52 +492,6 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
     /// or `Unknown` if it's known to be immutable.
     SILAccessEnforcement access;
     
-    /// A structure used for bookkeeping the on-demand formation and cleanup
-    /// of an addressable representation for an immutable value binding.
-    struct AddressableBuffer {
-      struct State {
-        // If the value needs to be reabstracted to provide an addressable
-        // representation, this SILValue owns the reabstracted representation.
-        SILValue reabstraction = SILValue();
-        // The stack allocation for the addressable representation.
-        SILValue allocStack = SILValue();
-        // The initiation of the in-memory borrow.
-        SILValue storeBorrow = SILValue();
-        
-        State(SILValue reabstraction,
-              SILValue allocStack,
-              SILValue storeBorrow)
-          : reabstraction(reabstraction), allocStack(allocStack),
-            storeBorrow(storeBorrow)
-        {}
-      };
-      
-      std::unique_ptr<State> state = nullptr;
-      
-      // If the variable cleanup is triggered before the addressable
-      // representation is demanded, but the addressable representation
-      // gets demanded later, we save the insertion points where the
-      // representation would be cleaned up so we can backfill them.
-      llvm::SmallVector<SILInstruction*, 1> cleanupPoints;
-      
-      AddressableBuffer() = default;
-      
-      AddressableBuffer(AddressableBuffer &&other)
-        : state(std::move(other.state))
-      {
-        cleanupPoints.swap(other.cleanupPoints);
-      }
-      
-      AddressableBuffer &operator=(AddressableBuffer &&other) {
-        state = std::move(other.state);
-        cleanupPoints.swap(other.cleanupPoints);
-        return *this;
-      }
-      
-      ~AddressableBuffer();
-    };
-    AddressableBuffer addressableBuffer;
-    
     VarLoc() = default;
     
     VarLoc(SILValue value, SILAccessEnforcement access,
@@ -534,50 +504,95 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// emitted. The map is queried to produce the lvalue for a DeclRefExpr to
   /// a local variable.
   llvm::DenseMap<ValueDecl*, VarLoc> VarLocs;
-  
-  // Represents an addressable buffer that has been allocated but not yet used.
-  struct PreparedAddressableBuffer {
-    SILInstruction *insertPoint = nullptr;
+
+  /// A structure used for bookkeeping the on-demand formation and cleanup
+  /// of an addressable representation for an immutable value binding.
+  struct AddressableBuffer {
+    struct State {
+      // If the value needs to be reabstracted to provide an addressable
+      // representation, this SILValue owns the reabstracted representation.
+      SILValue reabstraction = SILValue();
+      // The stack allocation for the addressable representation.
+      SILValue allocStack = SILValue();
+      // The initiation of the in-memory borrow.
+      SILValue storeBorrow = SILValue();
+      
+      State(SILValue reabstraction,
+            SILValue allocStack,
+            SILValue storeBorrow)
+        : reabstraction(reabstraction), allocStack(allocStack),
+          storeBorrow(storeBorrow)
+      {}
+    };
     
-    PreparedAddressableBuffer() = default;
+    llvm::PointerUnion<State *, VarDecl*> stateOrAlias = (State*)nullptr;
+
+    // The point at which the buffer will be inserted.
+    SILInstruction *insertPoint = nullptr;
     
-    PreparedAddressableBuffer(SILInstruction *insertPoint)
-      : insertPoint(insertPoint)
-    {}
+    // If the variable cleanup is triggered before the addressable
+    // representation is demanded, but the addressable representation
+    // gets demanded later, we save the insertion points where the
+    // representation would be cleaned up so we can backfill them.
+    struct CleanupPoint {
+      SILInstruction *inst;
+      CleanupState state;
+    };
+    llvm::SmallVector<CleanupPoint, 1> cleanupPoints;
     
-    PreparedAddressableBuffer(PreparedAddressableBuffer &&other)
-      : insertPoint(other.insertPoint)
+    AddressableBuffer() = default;
+
+    AddressableBuffer(VarDecl *original)
+      : stateOrAlias(original)
     {
-      other.insertPoint = nullptr;
     }
     
-    PreparedAddressableBuffer &operator=(PreparedAddressableBuffer &&other) {
-      insertPoint = other.insertPoint;
-      other.insertPoint = nullptr;
-      return *this;
+    AddressableBuffer(AddressableBuffer &&other)
+      : stateOrAlias(other.stateOrAlias)
+    {
+      other.stateOrAlias = (State*)nullptr;
+      cleanupPoints.swap(other.cleanupPoints);
     }
     
-    ~PreparedAddressableBuffer() {
-      if (insertPoint) {
-        // Remove the insertion point if it went unused.
-        insertPoint->eraseFromParent();
+    AddressableBuffer &operator=(AddressableBuffer &&other) {
+      if (auto state = stateOrAlias.dyn_cast<State*>()) {
+        delete state;
       }
+      stateOrAlias = other.stateOrAlias;
+      cleanupPoints.swap(other.cleanupPoints);
+      return *this;
+    }
+
+    State *getState() {
+      ASSERT(!isa<VarDecl *>(stateOrAlias) &&
+             "must get state from original AddressableBuffer");
+      return stateOrAlias.dyn_cast<State*>();
     }
+    
+    ~AddressableBuffer();
   };
-  llvm::DenseMap<VarDecl *, PreparedAddressableBuffer> AddressableBuffers;
+  llvm::DenseMap<ValueDecl *, AddressableBuffer> AddressableBuffers;
+    
+  AddressableBuffer *getAddressableBufferInfo(ValueDecl *vd);
   
   /// Establish the scope for the addressable buffer that might be allocated
   /// for a local variable binding.
   ///
   /// This must be enclosed within the scope of the value binding for the
   /// variable, and cover the scope in which the variable can be referenced.
-  void enterLocalVariableAddressableBufferScope(VarDecl *decl);
+  ///
+  /// If \c destroyVarCleanup is provided, then the state of the referenced
+  /// cleanup is tracked to determine whether the variable is initialized on
+  /// every exit path out of the scope. Otherwise, the variable is assumed to
+  /// be active on every exit.
+  void enterLocalVariableAddressableBufferScope(VarDecl *decl,
+                    CleanupHandle destroyVarCleanup = CleanupHandle::invalid());
   
   /// Get a stable address which is suitable for forming dependent pointers
   /// if possible.
-  SILValue getLocalVariableAddressableBuffer(VarDecl *decl,
-                                             SILLocation loc,
-                                             ValueOwnership ownership);
+  SILValue getVariableAddressableBuffer(VarDecl *decl,
+                                        SILLocation loc,
+                                        ValueOwnership ownership);
 
   /// The local auxiliary declarations for the parameters of this function that
   /// need to be emitted inside the next brace statement.
@@ -706,10 +721,17 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
       assert(Value != invalid() && Value != unnecessary());
       return Value != lazy();
     }
+
+    /// WARNING: Please do not call this unless you are completely sure that one
+    /// will always have an eager executor (i.e.: you are not emitting for an
+    /// initializer and more cases). To be safe please use
+    /// SILGenFunction::emitExpectedExecutor instead which handles the lazy case
+    /// correctly.
     SILValue getEager() const {
       assert(isEager());
       return Value;
     }
+
     void set(SILValue value) {
       assert(Value == invalid());
       assert(value != nullptr);
@@ -793,12 +815,26 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
     return TypeExpansionContext(getFunction());
   }
 
+  SILTypeProperties getTypeProperties(AbstractionPattern orig, Type subst) {
+    return F.getTypeProperties(orig, subst);
+  }
+  SILTypeProperties getTypeProperties(Type subst) {
+    return F.getTypeProperties(subst);
+  }
+  SILTypeProperties getTypeProperties(SILType type) {
+    return F.getTypeProperties(type);
+  }
+
   const TypeLowering &getTypeLowering(AbstractionPattern orig, Type subst) {
     return F.getTypeLowering(orig, subst);
   }
   const TypeLowering &getTypeLowering(Type t) {
     return F.getTypeLowering(t);
   }
+  const TypeLowering &getTypeLowering(SILType type) {
+    return F.getTypeLowering(type);
+  }
+
   CanSILFunctionType getSILFunctionType(TypeExpansionContext context,
                                         AbstractionPattern orig,
                                         CanFunctionType substFnType) {
@@ -835,9 +871,6 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   SILType getLoweredLoadableType(Type t) {
     return F.getLoweredLoadableType(t);
   }
-  const TypeLowering &getTypeLowering(SILType type) {
-    return F.getTypeLowering(type);
-  }
 
   SILType getSILInterfaceType(SILParameterInfo param) const {
     return silConv.getSILType(param, CanSILFunctionType(),
@@ -877,7 +910,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   FunctionTypeInfo getFunctionTypeInfo(CanAnyFunctionType fnType);
 
   /// A helper method that calls getFunctionTypeInfo that also marks global
-  /// actor isolated async closures that are not sendable as sendable.
+  /// actor-isolated async closures that are not sendable as sendable.
   FunctionTypeInfo getClosureTypeInfo(AbstractClosureExpr *expr);
 
   bool isEmittingTopLevelCode() { return IsEmittingTopLevelCode; }
@@ -933,7 +966,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// Return to the previous debug scope.
   void leaveDebugScope();
 
-  std::unique_ptr<Initialization>
+  InitializationPtr
   prepareIndirectResultInit(SILLocation loc,
                             AbstractionPattern origResultType,
                             CanType formalResultType,
@@ -943,7 +976,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// Check to see if an initalization for a SingleValueStmtExpr is active, and
   /// if the provided expression is for one of its branches. If so, returns the
   /// initialization to use for the expression. Otherwise returns \c nullptr.
-  std::unique_ptr<Initialization> getSingleValueStmtInit(Expr *E);
+  InitializationPtr getSingleValueStmtInit(Expr *E);
 
   //===--------------------------------------------------------------------===//
   // Entry points for codegen
@@ -1042,6 +1075,12 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// value assignment.
   void emitInitAccessor(AccessorDecl *accessor);
 
+  /// Generates code for the init accessor thunk that assigns the result of
+  /// calling a property wrapper's backing storage initializer into the backing
+  /// storage variable
+  void emitPropertyWrappedFieldInitAccessor(SILDeclRef function, Expr *value,
+                                            bool EmitProfilerIncrement);
+
   /// Generates code to emit the given setter reference to the given base value.
   SILValue emitApplyOfSetterToBase(SILLocation loc, SILDeclRef setter,
                                    ManagedValue base,
@@ -1297,6 +1336,12 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   emitHopToTargetActor(SILLocation loc, std::optional<ActorIsolation> actorIso,
                        std::optional<ManagedValue> actorSelf);
 
+  /// Emit a cleanup for a hop back to a target actor.
+  ///
+  /// Used to ensure that along error paths and normal scope exit paths we hop
+  /// back automatically.
+  CleanupHandle emitScopedHopToTargetActor(SILLocation loc, SILValue actor);
+
   /// Emit a hop to the target executor, returning a breadcrumb with enough
   /// enough information to hop back.
   ///
@@ -1756,19 +1801,6 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   // Patterns
   //===--------------------------------------------------------------------===//
 
-  SILValue emitOSVersionRangeCheck(SILLocation loc, const VersionRange &range,
-                                   bool forTargetVariant = false);
-  SILValue
-  emitOSVersionOrVariantVersionRangeCheck(SILLocation loc,
-                                          const VersionRange &targetRange,
-                                          const VersionRange &variantRange);
-  /// Emits either a single OS version range check or an OS version & variant
-  /// version range check automatically, depending on the active target triple
-  /// and requested versions.
-  SILValue emitZipperedOSVersionRangeCheck(SILLocation loc,
-                                           const VersionRange &targetRange,
-                                           const VersionRange &variantRange);
-
   void emitStmtCondition(StmtCondition Cond, JumpDest FalseDest, SILLocation loc,
                          ProfileCounter NumTrueTaken = ProfileCounter(),
                          ProfileCounter NumFalseTaken = ProfileCounter());
@@ -1976,6 +2008,10 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   ArgumentSource prepareAccessorBaseArg(SILLocation loc, ManagedValue base,
                                         CanType baseFormalType,
                                         SILDeclRef accessor);
+  ArgumentSource prepareAccessorBaseArgForFormalAccess(SILLocation loc,
+                                                       ManagedValue base,
+                                                       CanType baseFormalType,
+                                                       SILDeclRef accessor);
 
   RValue emitGetAccessor(
       SILLocation loc, SILDeclRef getter, SubstitutionMap substitutions,
@@ -2034,6 +2070,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
       PreparedArguments &&optionalSubscripts,
       SILType addressType, bool isOnSelfParameter);
 
+  bool canUnwindAccessorDeclRef(SILDeclRef accessorRef);
   CleanupHandle emitCoroutineAccessor(SILLocation loc, SILDeclRef accessor,
                                       SubstitutionMap substitutions,
                                       ArgumentSource &&optionalSelfValue,
@@ -2042,6 +2079,19 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
                                       SmallVectorImpl<ManagedValue> &yields,
                                       bool isOnSelfParameter);
 
+  ManagedValue emitBorrowMutateAccessor(SILLocation loc, SILDeclRef accessor,
+                                        SubstitutionMap substitutions,
+                                        ArgumentSource &&selfValue,
+                                        bool isSuper, bool isDirectUse,
+                                        PreparedArguments &&subscriptIndices,
+                                        bool isOnSelfParameter);
+
+  ManagedValue applyBorrowMutateAccessor(SILLocation loc, ManagedValue fn,
+                                         bool canUnwind, SubstitutionMap subs,
+                                         ArrayRef<ManagedValue> args,
+                                         CanSILFunctionType substFnType,
+                                         ApplyOptions options);
+
   RValue emitApplyConversionFunction(SILLocation loc,
                                      Expr *funcExpr,
                                      Type resultType,
@@ -2188,8 +2238,16 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
                                    TSanKind tsanKind = TSanKind::None);
   ManagedValue emitBorrowedLValue(SILLocation loc, LValue &&src,
                                   TSanKind tsanKind = TSanKind::None);
+  std::optional<ManagedValue>
+  tryEmitProjectedLValue(SILLocation loc, LValue &&src, TSanKind tsanKind);
   ManagedValue emitConsumedLValue(SILLocation loc, LValue &&src,
                                   TSanKind tsanKind = TSanKind::None);
+  /// Simply projects the LValue as a ManagedValue, allowing the caller
+  /// to check invariants and make adjustments manually.
+  ///
+  /// When in doubt, reach for emit[Borrowed|Consumed|etc]LValue.
+  ManagedValue emitRawProjectedLValue(SILLocation loc, LValue &&src,
+                                  TSanKind tsanKind = TSanKind::None);
   LValue emitOpenExistentialLValue(SILLocation loc,
                                    LValue &&existentialLV,
                                    CanArchetypeType openedArchetype,
@@ -2198,7 +2256,12 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
 
   RValue emitLoadOfLValue(SILLocation loc, LValue &&src, SGFContext C,
                           bool isBaseLValueGuaranteed = false);
-
+  PathComponent &&
+  drillToLastComponent(SILLocation loc,
+                       LValue &&lv,
+                       ManagedValue &addr,
+                       TSanKind tsanKind = TSanKind::None);
+                     
   /// Emit a reference to a method from within another method of the type.
   std::tuple<ManagedValue, SILType>
   emitSiblingMethodRef(SILLocation loc,
@@ -2210,6 +2273,11 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
 
   void emitReturnExpr(SILLocation loc, Expr *ret);
 
+  bool emitGuaranteedReturn(SILLocation loc, Expr *ret,
+                            SmallVectorImpl<SILValue> &directResults);
+
+  SILValue emitUncheckedGuaranteedConversion(SILValue value);
+
   void emitYield(SILLocation loc, MutableArrayRef<ArgumentSource> yieldValues,
                  ArrayRef<AbstractionPattern> origTypes,
                  JumpDest unwindDest);
@@ -2301,8 +2369,9 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
                                         PreparedArguments &&args, Type overriddenSelfType,
                                         SGFContext ctx);
 
-  CleanupHandle emitBeginApply(SILLocation loc, ManagedValue fn,
-                               SubstitutionMap subs, ArrayRef<ManagedValue> args,
+  CleanupHandle emitBeginApply(SILLocation loc, ManagedValue fn, bool canUnwind,
+                               SubstitutionMap subs,
+                               ArrayRef<ManagedValue> args,
                                CanSILFunctionType substFnType,
                                ApplyOptions options,
                                SmallVectorImpl<ManagedValue> &yields);
@@ -2315,7 +2384,8 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   std::tuple<MultipleValueInstructionResult *, CleanupHandle, SILValue,
              CleanupHandle>
   emitBeginApplyWithRethrow(SILLocation loc, SILValue fn, SILType substFnType,
-                            SubstitutionMap subs, ArrayRef<SILValue> args,
+                            bool canUnwind, SubstitutionMap subs,
+                            ArrayRef<SILValue> args,
                             SmallVectorImpl<SILValue> &yields);
   void emitEndApplyWithRethrow(SILLocation loc,
                                MultipleValueInstructionResult *token,
@@ -2330,9 +2400,8 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   SILBasicBlock *getTryApplyErrorDest(SILLocation loc,
                                       CanSILFunctionType fnTy,
                                       ExecutorBreadcrumb prevExecutor,
-                                      SILResultInfo errorResult,
-                                      SILValue indirectErrorAddr,
-                                      bool isSuppressed);
+                                      TaggedUnion<SILValue, SILType> errorAddrOrType,
+                                      bool suppressErrorPath);
 
   /// Emit a dynamic member reference.
   RValue emitDynamicMemberRef(SILLocation loc, SILValue operand,
@@ -2603,8 +2672,17 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
 
   enum class ThunkGenFlag {
     None,
-    ConvertingToNonIsolatedCaller,
-    ConvertingFromNonIsolatedCaller,
+
+    /// Set if the thunk has an implicit isolated parameter.
+    ///
+    /// The implication is that we shouldn't forward that parameter into the
+    /// callee as a normal parameter (if the callee has an implicit param, we
+    /// handle it through a different code path).
+    ThunkHasImplicitIsolatedParam = 0x1,
+
+    /// Set if the callee has an implicit isolated parameter that we need to
+    /// find the appropriate value for when we call it from the thunk.
+    CalleeHasImplicitIsolatedParam = 0x2,
   };
   using ThunkGenOptions = OptionSet<ThunkGenFlag>;
 
@@ -2613,7 +2691,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
       SILLocation loc, SmallVectorImpl<ManagedValue> &params,
       SmallVectorImpl<ManagedValue> *indirectResultParams = nullptr,
       SmallVectorImpl<ManagedValue> *indirectErrorParams = nullptr,
-      ThunkGenOptions options = {});
+      ManagedValue *implicitIsolationParam = nullptr);
 
   /// Build the type of a function transformation thunk.
   CanSILFunctionType buildThunkType(CanSILFunctionType &sourceType,
@@ -2668,7 +2746,13 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
                                            CanType outputType,  // `T.TangentVector`
                                            SGFContext ctxt);
 
-  
+  //===--------------------------------------------------------------------===//
+  // Availability
+  //===--------------------------------------------------------------------===//
+
+  /// Emit an `if #available` query, returning the resulting boolean test value.
+  SILValue emitIfAvailableQuery(SILLocation loc, PoundAvailableInfo *info);
+
   //===--------------------------------------------------------------------===//
   // Back Deployment thunks
   //===--------------------------------------------------------------------===//
@@ -2780,7 +2864,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   void emitPatternBinding(PatternBindingDecl *D, unsigned entry,
                           bool generateDebugInfo);
 
-  std::unique_ptr<Initialization>
+  InitializationPtr
   emitPatternBindingInitialization(Pattern *P, JumpDest failureDest,
                                    bool generateDebugInfo = true);
 
@@ -2804,7 +2888,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   void visitMacroExpansionDecl(MacroExpansionDecl *D);
 
   /// Emit an Initialization for a 'var' or 'let' decl in a pattern.
-  std::unique_ptr<Initialization>
+  InitializationPtr
   emitInitializationForVarDecl(VarDecl *vd, bool immutable,
                                bool generateDebugInfo = true);
 
@@ -2813,7 +2897,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// scope.
   /// \param ArgNo optionally describes this function argument's
   /// position for debug info.
-  std::unique_ptr<Initialization> emitLocalVariableWithCleanup(
+  InitializationPtr emitLocalVariableWithCleanup(
       VarDecl *D, std::optional<MarkUninitializedInst::Kind> kind,
       unsigned ArgNo = 0, bool generateDebugInfo = true);
 
@@ -2822,7 +2906,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// cleanups in the active scope.
   ///
   /// The initialization is guaranteed to be a single buffer.
-  std::unique_ptr<TemporaryInitialization>
+  TemporaryInitializationPtr
   emitTemporary(SILLocation loc, const TypeLowering &tempTL);
 
   /// Emit the allocation for a local temporary, provides an
@@ -2830,14 +2914,14 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// cleanups in the current active formal evaluation scope.
   ///
   /// The initialization is guaranteed to be a single buffer.
-  std::unique_ptr<TemporaryInitialization>
+  TemporaryInitializationPtr
   emitFormalAccessTemporary(SILLocation loc, const TypeLowering &tempTL);
 
   /// Provides an Initialization that can be used to initialize an already-
   /// allocated temporary, and registers cleanups in the active scope.
   ///
   /// The initialization is guaranteed to be a single buffer.
-  std::unique_ptr<TemporaryInitialization>
+  TemporaryInitializationPtr
   useBufferAsTemporary(SILValue addr, const TypeLowering &tempTL);
 
   /// Enter a currently-dormant cleanup to destroy the value in the
diff --git a/lib/SILGen/SILGenGlobalVariable.cpp b/lib/SILGen/SILGenGlobalVariable.cpp
index 1d3e03b55904a..909d377176e4b 100644
--- a/lib/SILGen/SILGenGlobalVariable.cpp
+++ b/lib/SILGen/SILGenGlobalVariable.cpp
@@ -231,8 +231,6 @@ void SILGenModule::emitGlobalInitialization(PatternBindingDecl *pd,
   auto onceSILTy
     = SILType::getPrimitiveObjectType(onceTy->getCanonicalType());
 
-  // TODO: include the module in the onceToken's name mangling.
-  // Then we can make it fragile.
   auto onceToken = SILGlobalVariable::create(M, SILLinkage::Private,
                                              IsNotSerialized,
                                              onceTokenBuffer, onceSILTy);
diff --git a/lib/SILGen/SILGenLValue.cpp b/lib/SILGen/SILGenLValue.cpp
index d2be1ea645047..9a24b81873af8 100644
--- a/lib/SILGen/SILGenLValue.cpp
+++ b/lib/SILGen/SILGenLValue.cpp
@@ -245,8 +245,9 @@ static LValueTypeData getPhysicalStorageTypeData(TypeExpansionContext context,
 }
 
 static bool shouldUseUnsafeEnforcement(VarDecl *var) {
-  if (var->isDebuggerVar())
+  if (var->isDebuggerVar()) {
     return true;
+  }
 
   return false;
 }
@@ -277,6 +278,22 @@ SILGenFunction::getDynamicEnforcement(VarDecl *var) {
   } else if (hasExclusivityAttr(var, ExclusivityAttr::Checked)) {
     return SILAccessEnforcement::Dynamic;
   }
+
+  // Access markers are especially load-bearing for the move-only checker,
+  // so we also emit `begin_access` markers for cases where storage
+  // is move-only.
+  // TODO: It seems useful to do this for all unchecked declarations, since
+  // access scopes are useful semantic information.
+  if (var->getTypeInContext()->isNoncopyable()) {
+    return SILAccessEnforcement::Unsafe;
+  }
+  if (auto param = dyn_cast<ParamDecl>(var)) {
+    if (param->getSpecifier() == ParamSpecifier::Borrowing
+        || param->getSpecifier() == ParamSpecifier::Consuming) {
+      return SILAccessEnforcement::Unsafe;
+    }
+  }
+  
   return std::nullopt;
 }
 
@@ -1238,6 +1255,11 @@ namespace {
       if (!base.getType().isLoadable(SGF.F)) {
         return base;
       }
+
+      if (base.getValue()->getType().isTrivial(SGF.F)) {
+        return SGF.B.createLoadTrivial(loc, base);
+      }
+
       auto result = SGF.B.createLoadBorrow(loc, base.getValue());
       // Mark the load_borrow as unchecked. We can't stop the source code from
       // trying to mutate or consume the same lvalue during this borrow, so
@@ -1411,27 +1433,9 @@ namespace {
     {
       AccessorArgs result;
       if (base) {
-        // Borrow the base, because we may need it again to invoke other
-        // accessors.
-        base = base.formalAccessBorrow(SGF, loc);
-        // If the base needs to be materialized, do so in
-        // the outer formal evaluation scope, since an addressor or
-        // other dependent value may want to point into the materialization.
-        auto &baseInfo = SGF.getConstantInfo(SGF.getTypeExpansionContext(),
-                                             accessor);
-                                             
-        if (!baseInfo.FormalPattern.isForeign()) {
-          auto baseFnTy = baseInfo.SILFnType;
-          
-          if (baseFnTy->getSelfParameter().isFormalIndirect()
-              && base.getType().isObject()
-              && SGF.silConv.useLoweredAddresses()) {
-            base = base.formallyMaterialize(SGF, loc);
-          }
-        }
-        
-        result.base = SGF.prepareAccessorBaseArg(loc, base, BaseFormalType,
-                                                 accessor);
+        result.base = SGF.prepareAccessorBaseArgForFormalAccess(loc, base,
+                                                                BaseFormalType,
+                                                                accessor);
       }
 
       if (!Indices.isNull())
@@ -1824,71 +1828,58 @@ namespace {
           isBackingVarVisible(cast<VarDecl>(Storage),
                               SGF.FunctionDC)) {
         // This is wrapped property. Instead of emitting a setter, emit an
-        // assign_by_wrapper with the allocating initializer function and the
-        // setter function as arguments. DefiniteInitialization will then decide
-        // between the two functions, depending if it's an initialization or a
-        // re-assignment.
-        //
+        // assign_or_init instruction with the allocating initializer function
+        // and the setter function as arguments. DefiniteInitialization will
+        // then decide between the two functions, depending if it's an
+        // initialization or a re-assignment.
+
         VarDecl *field = cast<VarDecl>(Storage);
         VarDecl *backingVar = field->getPropertyWrapperBackingProperty();
         assert(backingVar);
-        auto FieldType = field->getValueInterfaceType();
-        auto ValType = backingVar->getValueInterfaceType();
-        if (!Substitutions.empty()) {
-          FieldType = FieldType.subst(Substitutions);
-          ValType = ValType.subst(Substitutions);
-        }
 
-        auto typeData = getLogicalStorageTypeData(
-            SGF.getTypeExpansionContext(), SGF.SGM, getTypeData().AccessKind,
-            ValType->getCanonicalType());
+        // Create the init accessor thunk
+        SILDeclRef initConstant(
+            field, SILDeclRef::Kind::PropertyWrappedFieldInitAccessor);
+        SILValue initFRef = SGF.emitGlobalFunctionRef(loc, initConstant);
 
-        // Stores the address of the storage property.
+        // For nominal contexts, compute the self metatype
+        SILValue selfMetatype;
         ManagedValue proj;
-
-        // TODO: revist minimal
-        SILType varStorageType = SGF.SGM.Types.getSubstitutedStorageType(
-            TypeExpansionContext::minimal(), backingVar,
-            ValType->getCanonicalType());
-
-        if (!BaseFormalType) {
+        if (BaseFormalType) {
+          auto selfTy = base.getType().getASTType();
+          auto metatypeTy = MetatypeType::get(selfTy);
+          if (selfTy->getClassOrBoundGenericClass()) {
+            selfMetatype = SGF.B
+                               .createValueMetatype(
+                                   loc, SGF.getLoweredType(metatypeTy), base)
+                               .getValue();
+          } else {
+            assert(BaseFormalType->getStructOrBoundGenericStruct());
+            selfMetatype =
+                SGF.B.createMetatype(loc, SGF.getLoweredType(metatypeTy));
+          }
+        } else { // Dealing with a local context
           proj =
               SGF.maybeEmitValueOfLocalVarDecl(backingVar, AccessKind::Write);
-        } else if (BaseFormalType->mayHaveSuperclass()) {
-          RefElementComponent REC(backingVar, LValueOptions(), varStorageType,
-                                  typeData, /*actorIsolation=*/std::nullopt);
-          proj = std::move(REC).project(SGF, loc, base);
-        } else {
-          assert(BaseFormalType->getStructOrBoundGenericStruct());
-          StructElementComponent SEC(backingVar, varStorageType, typeData,
-                                     /*actorIsolation=*/std::nullopt);
-          proj = std::move(SEC).project(SGF, loc, base);
         }
 
-        // The property wrapper backing initializer forms an instance of
-        // the backing storage type from a wrapped value.
-        SILDeclRef initConstant(
-            field, SILDeclRef::Kind::PropertyWrapperBackingInitializer);
-        SILValue initFRef = SGF.emitGlobalFunctionRef(loc, initConstant);
-
+        auto argsPAI = BaseFormalType ? selfMetatype : ArrayRef<SILValue>();
         PartialApplyInst *initPAI =
-          SGF.B.createPartialApply(loc, initFRef,
-                                   Substitutions, ArrayRef<SILValue>(),
-                                   ParameterConvention::Direct_Guaranteed);
+            SGF.B.createPartialApply(loc, initFRef, Substitutions, argsPAI,
+                                     ParameterConvention::Direct_Guaranteed);
         ManagedValue initFn = SGF.emitManagedRValueWithCleanup(initPAI);
 
         // Create the allocating setter function. It captures the base address.
         SILValue setterFn =
             SGF.emitApplyOfSetterToBase(loc, Accessor, base, Substitutions);
 
-        // Create the assign_by_wrapper with the initializer and setter.
-
+        // Create the assign_or_init SIL instruction
         auto Mval =
             emitValue(SGF, loc, field, std::move(value), AccessorKind::Set);
-
-        SGF.B.createAssignByWrapper(loc, Mval.forward(SGF), proj.forward(SGF),
-                                    initFn.getValue(), setterFn,
-                                    AssignByWrapperInst::Unknown);
+        auto selfOrLocal = selfMetatype ? base.getValue() : proj.forward(SGF);
+        SGF.B.createAssignOrInit(loc, field, selfOrLocal, Mval.forward(SGF),
+                                 initFn.getValue(), setterFn,
+                                 AssignOrInitInst::Unknown);
         return;
       }
 
@@ -2297,6 +2288,47 @@ namespace {
   };
 }
 
+namespace {
+
+/// A physical component which involves calling borrow accessors.
+class BorrowMutateAccessorComponent
+    : public AccessorBasedComponent<PhysicalPathComponent> {
+public:
+  BorrowMutateAccessorComponent(AbstractStorageDecl *decl, SILDeclRef accessor,
+                                bool isSuper, bool isDirectAccessorUse,
+                                SubstitutionMap substitutions,
+                                CanType baseFormalType, LValueTypeData typeData,
+                                ArgumentList *argListForDiagnostics,
+                                PreparedArguments &&indices,
+                                bool isOnSelfParameter)
+      : AccessorBasedComponent(BorrowMutateKind, decl, accessor, isSuper,
+                               isDirectAccessorUse, substitutions,
+                               baseFormalType, typeData, argListForDiagnostics,
+                               std::move(indices), isOnSelfParameter) {}
+
+  using AccessorBasedComponent::AccessorBasedComponent;
+
+  ManagedValue project(SILGenFunction &SGF, SILLocation loc,
+                       ManagedValue base) &&
+      override {
+    assert(SGF.isInFormalEvaluationScope() &&
+           "offsetting l-value for modification without writeback scope");
+
+    ManagedValue result;
+
+    auto args = std::move(*this).prepareAccessorArgs(SGF, loc, base, Accessor);
+    auto value = SGF.emitBorrowMutateAccessor(
+        loc, Accessor, Substitutions, std::move(args.base), IsSuper,
+        IsDirectAccessorUse, std::move(args.Indices), IsOnSelfParameter);
+    return value;
+  }
+
+  void dump(raw_ostream &OS, unsigned indent) const override {
+    printBase(OS, indent, "BorrowMutateAccessorComponent");
+  }
+};
+} // namespace
+
 static ManagedValue
 makeBaseConsumableMaterializedRValue(SILGenFunction &SGF,
                                      SILLocation loc, ManagedValue base) {
@@ -2518,9 +2550,9 @@ namespace {
 
       // Perform the begin_apply.
       SmallVector<ManagedValue, 1> yields;
-      auto cleanup =
-        SGF.emitBeginApply(loc, projectFnRef, subs, { base, keyPathValue },
-                           substFnType, ApplyOptions(), yields);
+      auto cleanup = SGF.emitBeginApply(loc, projectFnRef, /*canUnwind=*/true,
+                                        subs, {base, keyPathValue}, substFnType,
+                                        ApplyOptions(), yields);
 
       // Push an operation to do the end_apply.
       pushEndApplyWriteback(SGF, loc, cleanup, getTypeData());
@@ -3027,13 +3059,19 @@ class LLVM_LIBRARY_VISIBILITY SILGenBorrowedBaseVisitor
   SILGenLValue &SGL;
   SILGenFunction &SGF;
   AbstractionPattern Orig;
-
-  SILGenBorrowedBaseVisitor(SILGenLValue &SGL,
-                            SILGenFunction &SGF,
-                            AbstractionPattern Orig)
-      : SGL(SGL), SGF(SGF), Orig(Orig) {}
-
-  static bool isNonCopyableBaseBorrow(SILGenFunction &SGF, Expr *e) {
+  bool forGuaranteedReturn;
+  bool forGuaranteedAddressReturn;
+
+  SILGenBorrowedBaseVisitor(SILGenLValue &SGL, SILGenFunction &SGF,
+                            AbstractionPattern Orig,
+                            bool forGuaranteedReturn = false,
+                            bool forGuaranteedAddressReturn = false)
+      : SGL(SGL), SGF(SGF), Orig(Orig),
+        forGuaranteedReturn(forGuaranteedReturn),
+        forGuaranteedAddressReturn(forGuaranteedAddressReturn) {}
+
+  static bool isNonCopyableBaseBorrow(SILGenFunction &SGF, Expr *e,
+                                      LValueOptions options) {
     if (auto *m = dyn_cast<MemberRefExpr>(e)) {
       // If our m is a pure noncopyable type or our base is, we need to perform
       // a noncopyable base borrow.
@@ -3041,8 +3079,14 @@ class LLVM_LIBRARY_VISIBILITY SILGenBorrowedBaseVisitor
       // DISCUSSION: We can have a noncopyable member_ref_expr with a copyable
       // base if the noncopyable member_ref_expr is from a computed method. In
       // such a case, we want to ensure that we wrap things the right way.
-      return m->getType()->isNoncopyable() ||
-          m->getBase()->getType()->isNoncopyable();
+      if (m->getType()->isNoncopyable() ||
+          m->getBase()->getType()->isNoncopyable()) {
+        return true;
+      }
+
+      if (options.ForGuaranteedAddressReturn || options.ForGuaranteedReturn) {
+        return true;
+      }
     }
 
     if (auto *le = dyn_cast<LoadExpr>(e)) {
@@ -3050,6 +3094,9 @@ class LLVM_LIBRARY_VISIBILITY SILGenBorrowedBaseVisitor
       if (le->getType()->isNoncopyable()) {
         return true;
       }
+      if (options.ForGuaranteedAddressReturn || options.ForGuaranteedReturn) {
+        return true;
+      }
       // Otherwise, check if the thing we're loading from is a noncopyable
       // param decl.
       e = le->getSubExpr();
@@ -3061,6 +3108,9 @@ class LLVM_LIBRARY_VISIBILITY SILGenBorrowedBaseVisitor
       if (de->getType()->isNoncopyable()) {
         return true;
       }
+      if (options.ForGuaranteedAddressReturn || options.ForGuaranteedReturn) {
+        return true;
+      }
       // If the decl ref refers to a parameter with an explicit ownership
       // modifier, it is not implicitly copyable.
       if (auto pd = dyn_cast<ParamDecl>(de->getDecl())) {
@@ -3084,7 +3134,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenBorrowedBaseVisitor
   /// define a visitor stub, defer back to SILGenLValue's visitRec as it is
   /// most-likely a non-lvalue root expression.
   LValue visitExpr(Expr *e, SGFAccessKind accessKind, LValueOptions options) {
-    assert(!isNonCopyableBaseBorrow(SGF, e)
+    assert(!isNonCopyableBaseBorrow(SGF, e, options)
             && "unexpected recursion in SILGenLValue::visitRec!");
 
     return SGL.visitRec(e, accessKind, options, Orig);
@@ -3098,10 +3148,12 @@ class LLVM_LIBRARY_VISIBILITY SILGenBorrowedBaseVisitor
 
     assert(!e->getType()->is<LValueType>());
 
+    auto pair = std::make_pair<>(e->getSourceRange(), SGF.FunctionDC);
+
     auto accessSemantics = e->getAccessSemantics();
     AccessStrategy strategy = var->getAccessStrategy(
         accessSemantics, getFormalAccessKind(accessKind),
-        SGF.SGM.M.getSwiftModule(), SGF.F.getResilienceExpansion(),
+        SGF.SGM.M.getSwiftModule(), SGF.F.getResilienceExpansion(), pair,
         /*useOldABI=*/false);
 
     auto baseFormalType = getBaseFormalType(e->getBase());
@@ -3111,9 +3163,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenBorrowedBaseVisitor
     // If the access produces a dependent value, and the base is addressable,
     // then
     if (!formalRValueType->isEscapable()
-        && SGF.getTypeLowering(baseFormalType)
-              .getRecursiveProperties()
-              .isAddressableForDependencies()) {
+        && SGF.getTypeProperties(baseFormalType).isAddressableForDependencies()) {
       addressable = true;
       orig = AbstractionPattern::getOpaque();
     }
@@ -3140,6 +3190,26 @@ class LLVM_LIBRARY_VISIBILITY SILGenBorrowedBaseVisitor
     // We are going to immediately use this base value, so we want to borrow it.
     ManagedValue mv =
         SGF.emitRValueAsSingleValue(e, SGFContext::AllowImmediatePlusZero);
+
+    if (forGuaranteedReturn && mv.getValue()->getType().isMoveOnly()) {
+      // SILGen eagerly generates copy_value +
+      // mark_unresolved_non_copyable_value for ~Copyable base values. The
+      // generated mark_unresolved_non_copyable_value instructions drive
+      // move-only checker diagnostics ensuring there are no consuming uses of
+      // this value. However, the copy_value +
+      // mark_unresolved_non_copyable_value pair creates an artifical scope out
+      // of which we cannot legally return a
+      // @guaranteed value.
+      // We have already diagosed borrow accessor returns, ensuring they return
+      // only projections, since projections don't create any consuming used we
+      // can safely look through copy_value + mark_unresolved_non_copyable_value + begin_borrow
+      // instructions while emitting the base value.
+      auto baseValue = lookThroughMoveOnlyCheckerPattern(mv.getValue());
+      assert(cast<SILArgument>(baseValue) ==
+             SGF.getFunction().getSelfArgument());
+      return ManagedValue::forBorrowedObjectRValue(baseValue);
+    }
+
     if (mv.isPlusZeroRValueOrTrivial())
       return mv;
 
@@ -3234,9 +3304,14 @@ LValue SILGenLValue::visitRec(Expr *e, SGFAccessKind accessKind,
   // a `borrow x` operator, the operator is used on the base here), we want to
   // apply the lvalue within a formal access to the original value instead of
   // an actual loaded copy.
-  if (SILGenBorrowedBaseVisitor::isNonCopyableBaseBorrow(SGF, e)) {
-    SILGenBorrowedBaseVisitor visitor(*this, SGF, orig);
+  if (SILGenBorrowedBaseVisitor::isNonCopyableBaseBorrow(SGF, e, options)) {
+    SILGenBorrowedBaseVisitor visitor(*this, SGF, orig,
+                                      options.ForGuaranteedReturn,
+                                      options.ForGuaranteedAddressReturn);
     auto accessKind = SGFAccessKind::BorrowedObjectRead;
+    if (options.ForGuaranteedAddressReturn) {
+      accessKind = SGFAccessKind::BorrowedAddressRead;
+    }
     assert(!e->getType()->is<LValueType>()
         && "maybe need SGFAccessKind::BorrowedAddressRead ?");
     return visitor.visit(e, accessKind, options);
@@ -3358,8 +3433,15 @@ namespace {
                                       AccessKind, FormalRValueType);
         return asImpl().emitUsingInitAccessor(accessor, isDirect, typeData);
       }
+      case AccessorKind::Borrow:
+      case AccessorKind::Mutate: {
+        auto typeData = getPhysicalStorageTypeData(
+            SGF.getTypeExpansionContext(), SGF.SGM, AccessKind, Storage, Subs,
+            FormalRValueType);
+        return asImpl().emitUsingBorrowMutateAccessor(accessor, isDirect,
+                                                      typeData);
+      }
       }
-
       llvm_unreachable("bad kind");
     }
   };
@@ -3379,7 +3461,7 @@ static LValue emitLValueForNonMemberVarDecl(
   auto access = getFormalAccessKind(accessKind);
   auto strategy = var->getAccessStrategy(
       semantics, access, SGF.SGM.M.getSwiftModule(),
-      SGF.F.getResilienceExpansion(), /*useOldABI=*/false);
+      SGF.F.getResilienceExpansion(), std::nullopt, /*useOldABI=*/false);
 
   lv.addNonMemberVarComponent(SGF, loc, var, subs, options, accessKind,
                               strategy, formalRValueType, actorIso);
@@ -3449,6 +3531,11 @@ void LValue::addNonMemberVarComponent(
           PreparedArguments(), /*isOnSelfParameter*/ false);
     }
 
+    void emitUsingBorrowMutateAccessor(SILDeclRef accessor, bool isDirect,
+                                       LValueTypeData typeData) {
+      llvm_unreachable("borrow/mutate accessor is not implemented");
+    }
+
     void emitUsingGetterSetter(SILDeclRef accessor,
                                bool isDirect,
                                LValueTypeData typeData) {
@@ -3502,7 +3589,8 @@ void LValue::addNonMemberVarComponent(
 
       std::optional<SILAccessEnforcement> enforcement;
       if (!Storage->isLet()) {
-        if (Options.IsNonAccessing) {
+        if (Options.IsNonAccessing || Options.ForGuaranteedReturn ||
+            Options.ForGuaranteedAddressReturn) {
           enforcement = std::nullopt;
         } else if (Storage->getDeclContext()->isLocalContext()) {
           enforcement = SGF.getUnknownEnforcement(Storage);
@@ -3661,8 +3749,7 @@ RValue SILGenFunction::emitRValueForNonMemberVarDecl(SILLocation loc,
     // If we have self, see if we are in an 'init' delegation sequence. If so,
     // call out to the special delegation init routine. Otherwise, use the
     // normal RValue emission logic.
-    if (var->getName() == getASTContext().Id_self &&
-        SelfInitDelegationState != NormalSelf) {
+    if (var->isSelfParameter() && SelfInitDelegationState != NormalSelf) {
       auto rvalue =
         emitRValueForSelfInDelegationInit(loc, formalRValueType, accessAddr, C);
       return propagateRValuePastAccess(std::move(rvalue));
@@ -4015,6 +4102,7 @@ LValue SILGenLValue::visitMemberRefExpr(MemberRefExpr *e,
   AccessStrategy strategy = var->getAccessStrategy(
       accessSemantics, getFormalAccessKind(accessKind),
       SGF.SGM.M.getSwiftModule(), SGF.F.getResilienceExpansion(),
+      std::make_pair<>(e->getSourceRange(), SGF.FunctionDC),
       /*useOldABI=*/isSynthesizedDefaultImplementionThunk(SGF));
 
   bool isOnSelfParameter = isCallToSelfOfCurrentFunction(SGF, e);
@@ -4036,6 +4124,7 @@ LValue SILGenLValue::visitMemberRefExpr(MemberRefExpr *e,
       strategy = var->getAccessStrategy(
           accessSemantics, getFormalAccessKind(accessKind),
           SGF.SGM.M.getSwiftModule(), SGF.F.getResilienceExpansion(),
+          std::make_pair<>(e->getSourceRange(), SGF.FunctionDC),
           /*useOldABI=*/false);
     }
   }
@@ -4047,9 +4136,7 @@ LValue SILGenLValue::visitMemberRefExpr(MemberRefExpr *e,
   // If the access produces a dependent value, and the base is addressable-for-
   // dependencies, then request an addressable base.
   if (!substFormalRValueType->isEscapable()
-      && SGF.getTypeLowering(baseTy)
-            .getRecursiveProperties()
-            .isAddressableForDependencies()) {
+      && SGF.getTypeProperties(baseTy).isAddressableForDependencies()) {
     addressable = true;
     orig = AbstractionPattern::getOpaque();
   }
@@ -4130,6 +4217,14 @@ struct MemberStorageAccessEmitter : AccessEmitter<Impl, StorageType> {
         ArgListForDiagnostics, std::move(Indices), IsOnSelfParameter);
   }
 
+  void emitUsingBorrowMutateAccessor(SILDeclRef accessor, bool isDirect,
+                                     LValueTypeData typeData) {
+    assert(!ActorIso);
+    LV.add<BorrowMutateAccessorComponent>(
+        Storage, accessor, IsSuper, isDirect, Subs, BaseFormalType, typeData,
+        ArgListForDiagnostics, std::move(Indices), IsOnSelfParameter);
+  }
+
   void emitUsingGetterSetter(SILDeclRef accessor,
                              bool isDirect,
                              LValueTypeData typeData) {
@@ -4237,6 +4332,7 @@ LValue SILGenLValue::visitSubscriptExpr(SubscriptExpr *e,
   auto strategy = decl->getAccessStrategy(
       accessSemantics, getFormalAccessKind(accessKind),
       SGF.SGM.M.getSwiftModule(), SGF.F.getResilienceExpansion(),
+      std::make_pair<>(e->getSourceRange(), SGF.FunctionDC),
       /*useOldABI=*/isSynthesizedDefaultImplementionThunk(SGF));
 
   bool isOnSelfParameter = isCallToSelfOfCurrentFunction(SGF, e);
@@ -4257,6 +4353,7 @@ LValue SILGenLValue::visitSubscriptExpr(SubscriptExpr *e,
       strategy = decl->getAccessStrategy(
           accessSemantics, getFormalAccessKind(accessKind),
           SGF.SGM.M.getSwiftModule(), SGF.F.getResilienceExpansion(),
+          std::make_pair<>(e->getSourceRange(), SGF.FunctionDC),
           /*useOldABI=*/false);
     }
   }
@@ -4268,9 +4365,7 @@ LValue SILGenLValue::visitSubscriptExpr(SubscriptExpr *e,
   // If the access produces a dependent value, and the base is addressable,
   // then
   if (!formalRValueType->isEscapable()
-      && SGF.getTypeLowering(baseTy)
-            .getRecursiveProperties()
-            .isAddressableForDependencies()) {
+      && SGF.getTypeProperties(baseTy).isAddressableForDependencies()) {
     addressable = true;
     orig = AbstractionPattern::getOpaque();
   }
@@ -4727,7 +4822,7 @@ LValue SILGenFunction::emitPropertyLValue(SILLocation loc, ManagedValue base,
 
   AccessStrategy strategy = ivar->getAccessStrategy(
       semantics, getFormalAccessKind(accessKind), SGM.M.getSwiftModule(),
-      F.getResilienceExpansion(), /*useOldABI=*/false);
+      F.getResilienceExpansion(), std::nullopt, /*useOldABI=*/false);
 
   auto baseAccessKind =
     getBaseAccessKind(SGM, ivar, accessKind, strategy, baseFormalType,
@@ -5222,12 +5317,22 @@ void SILGenFunction::emitSemanticStore(SILLocation loc,
     dest = B.createMoveOnlyWrapperToCopyableAddr(loc, dest);
   }
 
+  // If the dest type differs only in concurrency annotations, we can cast them
+  // off.
+  if (dest->getType().getObjectType() != rvalue->getType().getObjectType()
+      && dest->getType().stripConcurrency(/*recursive*/true, /*dropGlobal*/true)
+        == rvalue->getType().stripConcurrency(true, true)) {
+    dest = B.createUncheckedAddrCast(loc, dest, rvalue->getType().getAddressType());
+  }
+
   // Easy case: the types match.
   if (rvalue->getType().getObjectType() == dest->getType().getObjectType()) {
     assert(!silConv.useLoweredAddresses() ||
            (dest->getType().isAddressOnly(F) == rvalue->getType().isAddress()));
     if (rvalue->getType().isAddress()) {
-      B.createCopyAddr(loc, rvalue, dest, IsTake, isInit);
+      B.createCopyAddr(loc, rvalue, dest,
+                       rvalue->getType().isTrivial(F) ? IsNotTake : IsTake,
+                       isInit);
     } else {
       emitUnloweredStoreOfCopy(B, loc, rvalue, dest, isInit);
     }
@@ -5333,17 +5438,16 @@ static ManagedValue drillIntoComponent(SILGenFunction &SGF,
 
 /// Find the last component of the given lvalue and derive a base
 /// location for it.
-static PathComponent &&
-drillToLastComponent(SILGenFunction &SGF,
-                     SILLocation loc,
-                     LValue &&lv,
-                     ManagedValue &addr,
-                     TSanKind tsanKind = TSanKind::None) {
+PathComponent &&
+SILGenFunction::drillToLastComponent(SILLocation loc,
+                                     LValue &&lv,
+                                     ManagedValue &addr,
+                                     TSanKind tsanKind) {
   assert(lv.begin() != lv.end() &&
          "lvalue must have at least one component");
 
   for (auto i = lv.begin(), e = lv.end() - 1; i != e; ++i) {
-    addr = drillIntoComponent(SGF, loc, std::move(**i), addr, tsanKind);
+    addr = drillIntoComponent(*this, loc, std::move(**i), addr, tsanKind);
   }
 
   return std::move(**(lv.end() - 1));
@@ -5355,7 +5459,7 @@ static ArgumentSource emitBaseValueForAccessor(SILGenFunction &SGF,
                                                SILDeclRef accessor) {
   ManagedValue base;
   PathComponent &&component =
-    drillToLastComponent(SGF, loc, std::move(lvalue), base);
+    SGF.drillToLastComponent(loc, std::move(lvalue), base);
   base = drillIntoComponent(SGF, loc, std::move(component), base,
                             TSanKind::None);
 
@@ -5379,7 +5483,7 @@ RValue SILGenFunction::emitLoadOfLValue(SILLocation loc, LValue &&src,
 
     ManagedValue addr;
     PathComponent &&component =
-        drillToLastComponent(*this, loc, std::move(src), addr);
+        drillToLastComponent(loc, std::move(src), addr);
 
     // If the last component is physical, drill down and load from it.
     if (component.isPhysical()) {
@@ -5443,7 +5547,7 @@ RValue SILGenFunction::emitRValueForStorageLoad(
     bool isBaseGuaranteed) {
   AccessStrategy strategy = storage->getAccessStrategy(
       semantics, AccessKind::Read, SGM.M.getSwiftModule(),
-      F.getResilienceExpansion(), /*useOldABI=*/false);
+      F.getResilienceExpansion(), std::nullopt, /*useOldABI=*/false);
 
   // If we should call an accessor of some kind, do so.
   if (strategy.getKind() != AccessStrategy::Storage) {
@@ -5581,11 +5685,8 @@ ManagedValue SILGenFunction::emitAddressOfLValue(SILLocation loc,
          src.getAccessKind() == SGFAccessKind::OwnedAddressConsume ||
          src.getAccessKind() == SGFAccessKind::ReadWrite);
 
-  ManagedValue addr;
-  PathComponent &&component =
-    drillToLastComponent(*this, loc, std::move(src), addr, tsanKind);
+  ManagedValue addr = emitRawProjectedLValue(loc, std::move(src), tsanKind);
 
-  addr = drillIntoComponent(*this, loc, std::move(component), addr, tsanKind);
   assert(addr.getType().isAddress() &&
          "resolving lvalue did not give an address");
   return ManagedValue::forLValue(addr.getValue());
@@ -5599,12 +5700,7 @@ ManagedValue SILGenFunction::emitBorrowedLValue(SILLocation loc,
          src.getAccessKind() == SGFAccessKind::BorrowedObjectRead);
   bool isIgnored = src.getAccessKind() == SGFAccessKind::IgnoredRead;
 
-  ManagedValue base;
-  PathComponent &&component =
-    drillToLastComponent(*this, loc, std::move(src), base, tsanKind);
-
-  auto value =
-    drillIntoComponent(*this, loc, std::move(component), base, tsanKind);
+  auto value = emitRawProjectedLValue(loc, std::move(src), tsanKind);
 
   // If project() returned an owned value, and the caller cares, borrow it.
   if (value.hasCleanup() && !isIgnored)
@@ -5612,18 +5708,49 @@ ManagedValue SILGenFunction::emitBorrowedLValue(SILLocation loc,
   return value;
 }
 
+std::optional<ManagedValue>
+SILGenFunction::tryEmitProjectedLValue(SILLocation loc, LValue &&src,
+                                       TSanKind tsanKind) {
+  assert(src.getAccessKind() == SGFAccessKind::BorrowedAddressRead ||
+         src.getAccessKind() == SGFAccessKind::BorrowedObjectRead ||
+         src.getAccessKind() == SGFAccessKind::Write);
+
+  for (auto component = src.begin(); component != src.end(); component++) {
+    if (component->get()->getKind() != PathComponent::BorrowMutateKind &&
+        component->get()->getKind() != PathComponent::StructElementKind &&
+        component->get()->getKind() != PathComponent::TupleElementKind &&
+        component->get()->getKind() != PathComponent::ValueKind) {
+      return std::nullopt;
+    }
+  }
+
+  ManagedValue base;
+  PathComponent &&component =
+      drillToLastComponent(loc, std::move(src), base, tsanKind);
+
+  auto value =
+      drillIntoComponent(*this, loc, std::move(component), base, tsanKind);
+  ASSERT(!value.hasCleanup());
+  return value;
+}
+
 ManagedValue SILGenFunction::emitConsumedLValue(SILLocation loc, LValue &&src,
                                                 TSanKind tsanKind) {
   assert(isConsumeAccess(src.getAccessKind()));
+  return emitRawProjectedLValue(loc, std::move(src), tsanKind);
+}
 
+ManagedValue SILGenFunction::emitRawProjectedLValue(SILLocation loc,
+                                                LValue &&src,
+                                                TSanKind tsanKind) {
   ManagedValue base;
   PathComponent &&component =
-      drillToLastComponent(*this, loc, std::move(src), base, tsanKind);
+    drillToLastComponent(loc, std::move(src), base, tsanKind);
 
-  auto value =
-      drillIntoComponent(*this, loc, std::move(component), base, tsanKind);
+  ManagedValue result =
+    drillIntoComponent(*this, loc, std::move(component), base, tsanKind);
 
-  return value;
+  return result;
 }
 
 LValue
@@ -5694,10 +5821,6 @@ void SILGenFunction::emitAssignToLValue(SILLocation loc, RValue &&src,
   emitAssignToLValue(loc, ArgumentSource(loc, std::move(src)), std::move(dest));
 }
 
-namespace {
-
-} // end anonymous namespace
-
 /// Checks if the last component of the LValue refers to the given var decl.
 static bool referencesVar(PathComponent const& comp, VarDecl *var) {
   if (comp.getKind() != PathComponent::RefElementKind)
@@ -5746,7 +5869,7 @@ void SILGenFunction::emitAssignToLValue(SILLocation loc,
   // properties we need to write back to.
   ManagedValue destAddr;
   PathComponent &&component =
-    drillToLastComponent(*this, loc, std::move(dest), destAddr);
+    drillToLastComponent(loc, std::move(dest), destAddr);
   
   // Write to the tail component.
   if (component.isPhysical()) {
diff --git a/lib/SILGen/SILGenLazyConformance.cpp b/lib/SILGen/SILGenLazyConformance.cpp
index 90cc4772a9219..31674443b117f 100644
--- a/lib/SILGen/SILGenLazyConformance.cpp
+++ b/lib/SILGen/SILGenLazyConformance.cpp
@@ -110,6 +110,13 @@ void SILGenModule::useConformancesFromType(CanType type) {
     if (isa<ProtocolDecl>(decl))
       return;
 
+    // If this is an imported noncopyable type with a deinitializer, record it.
+    if (decl->hasClangNode() && !decl->canBeCopyable() &&
+        decl->getValueTypeDestructor() &&
+        importedNontrivialNoncopyableTypes.insert(decl).second) {
+      visitImportedNontrivialNoncopyableType(decl);
+    }
+
     auto genericSig = decl->getGenericSignature();
     if (!genericSig)
       return;
diff --git a/lib/SILGen/SILGenPack.cpp b/lib/SILGen/SILGenPack.cpp
index d402193e758a7..729b633479a05 100644
--- a/lib/SILGen/SILGenPack.cpp
+++ b/lib/SILGen/SILGenPack.cpp
@@ -1099,7 +1099,7 @@ SILGenFunction::emitPackTransform(SILLocation loc,
     // If this is not a simple projection, project the output tuple element
     // and encourage the transformation to initialize into it.
     SILValue outputEltAddr;
-    std::unique_ptr<TemporaryInitialization> outputEltInit;
+    TemporaryInitializationPtr outputEltInit;
     if (!isSimpleProjection) {
       outputEltAddr = B.createTuplePackElementAddr(loc, packExpansionIndex,
                                                    outputTupleAddr,
@@ -1131,8 +1131,9 @@ SILGenFunction::emitPackTransform(SILLocation loc,
       outputEltAddr = outputElt.forward(*this);
 
     // Otherwise, if the value is not already in the temporary, put it there.
-    } else if (!outputElt.isInContext()) {
-      outputElt.forwardInto(*this, loc, outputEltInit.get());
+    } else {
+      if (!outputElt.isInContext())
+        outputElt.forwardInto(*this, loc, outputEltInit.get());
       outputEltInit->getManagedAddress().forward(*this);
     }
 
diff --git a/lib/SILGen/SILGenPattern.cpp b/lib/SILGen/SILGenPattern.cpp
index cbac3273a48e6..4513cf5c4e587 100644
--- a/lib/SILGen/SILGenPattern.cpp
+++ b/lib/SILGen/SILGenPattern.cpp
@@ -24,7 +24,6 @@
 #include "swift/AST/SILOptions.h"
 #include "swift/AST/SubstitutionMap.h"
 #include "swift/AST/Types.h"
-#include "swift/Basic/Assertions.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/ProfileCounter.h"
 #include "swift/Basic/STLExtras.h"
@@ -241,7 +240,7 @@ static bool isWildcardPattern(const Pattern *p) {
 
 /// Check to see if the given pattern is a specializing pattern,
 /// and return a semantic pattern for it.
-Pattern *getSpecializingPattern(Pattern *p) {
+static Pattern *getSpecializingPattern(Pattern *p) {
   // Empty entries are basically AnyPatterns.
   if (!p) return nullptr;
 
@@ -975,9 +974,8 @@ class SpecializedArgForwarder : private ArgForwarderBase {
     if (IsFinalUse) {
       ArgForwarderBase::forwardIntoIrrefutable(value);
       return value;
-    } else {
-      return ArgForwarderBase::forward(value, loc);
     }
+    return ArgForwarderBase::forward(value, loc);
   }
 };
 
@@ -1310,7 +1308,7 @@ void PatternMatchEmission::bindIrrefutableBorrows(const ClauseRow &row,
       // explicitly `borrowing`, then we can bind it as a normal copyable
       // value.
       if (named->getDecl()->getIntroducer() != VarDecl::Introducer::Borrowing
-          && !named->getType()->isNoncopyable()) {
+          && named->getType()->isCopyable()) {
         bindVariable(pattern, named->getDecl(), args[i], forIrrefutableRow,
                      hasMultipleItems);
       } else {
@@ -1407,7 +1405,10 @@ void PatternMatchEmission::bindBorrow(Pattern *pattern, VarDecl *var,
   auto bindValue = value.asBorrowedOperand2(SGF, pattern).getFinalManagedValue();
 
   // Borrow bindings of copyable type should still be no-implicit-copy.
-  if (!bindValue.getType().isMoveOnly()) {
+  //
+  // If we're relying on ManualOwnership for explicit-copies enforcement,
+  // we don't need the MoveOnlyWrapper.
+  if (!bindValue.getType().isMoveOnly() && !SGF.B.hasManualOwnershipAttr()) {
     if (bindValue.getType().isAddress()) {
       bindValue = ManagedValue::forBorrowedAddressRValue(
         SGF.B.createCopyableToMoveOnlyWrapperAddr(pattern, bindValue.getValue()));
@@ -1879,7 +1880,7 @@ emitCastOperand(SILGenFunction &SGF, SILLocation loc,
   assert(src.getFinalConsumption() != CastConsumptionKind::TakeOnSuccess &&
          "Loadable types can not have take_on_success?!");
 
-  std::unique_ptr<TemporaryInitialization> init;
+  TemporaryInitializationPtr init;
   SGFContext ctx;
   if (requiresAddress) {
     init = SGF.emitTemporary(loc, srcAbstractTL);
@@ -2838,7 +2839,7 @@ void PatternMatchEmission::initSharedCaseBlockDest(CaseStmt *caseBlock,
   result.first->second.first = block;
 
   // Add args for any pattern variables if we have any.
-  for (auto *vd : caseBlock->getCaseBodyVariablesOrEmptyArray()) {
+  for (auto *vd : caseBlock->getCaseBodyVariables()) {
     if (!vd->hasName())
       continue;
 
@@ -2869,7 +2870,7 @@ void PatternMatchEmission::emitAddressOnlyAllocations() {
     // If we have a shared case with bound decls, setup the arguments for the
     // shared block by emitting the temporary allocation used for the arguments
     // of the shared block.
-    for (auto *vd : caseBlock->getCaseBodyVariablesOrEmptyArray()) {
+    for (auto *vd : caseBlock->getCaseBodyVariables()) {
       if (!vd->hasName())
         continue;
 
@@ -2960,7 +2961,7 @@ void PatternMatchEmission::emitSharedCaseBlocks(
     SWIFT_DEFER { assert(SGF.getCleanupsDepth() == PatternMatchStmtDepth); };
 
     if (!caseBlock->hasCaseBodyVariables()) {
-      emitCaseBody(caseBlock);
+      bodyEmitter(caseBlock);
       continue;
     }
 
@@ -3175,6 +3176,7 @@ static void switchCaseStmtSuccessCallback(SILGenFunction &SGF,
           expectedLoc = SILGenFunction::VarLoc(vdLoc->second.value,
                                                vdLoc->second.access,
                                                vdLoc->second.box);
+          SGF.AddressableBuffers[expected] = vd;
 
           // Emit a debug description for the variable, nested within a scope
           // for the pattern match.
@@ -3323,11 +3325,13 @@ static bool isBorrowableSubject(SILGenFunction &SGF,
   if (!storage) {
     return false;
   }
-  
+
+  auto pair = std::make_pair<>(subjectExpr->getSourceRange(), SGF.FunctionDC);
+
   // Check the access strategy used to read the storage.
   auto strategy =
       storage->getAccessStrategy(access, AccessKind::Read, SGF.SGM.SwiftModule,
-                                 SGF.F.getResilienceExpansion(),
+                                 SGF.F.getResilienceExpansion(), pair,
                                  /*useOldABI=*/false);
 
   switch (strategy.getKind()) {
@@ -3356,6 +3360,10 @@ static bool isBorrowableSubject(SILGenFunction &SGF,
     case AccessorKind::WillSet:
     case AccessorKind::DidSet:
       llvm_unreachable("should not be involved in a read");
+    case AccessorKind::Borrow:
+      llvm_unreachable("borrow accessor is not yet implemented");
+    case AccessorKind::Mutate:
+      llvm_unreachable("mutate accessor is not yet implemented");
     }
     llvm_unreachable("switch not covered?");
     
@@ -3499,7 +3507,7 @@ void SILGenFunction::emitSwitchStmt(SwitchStmt *S) {
   //   exits out of the switch.
   //
   // When we break out of a case block, we take the subject's remnants with us
-  // in the former case, but not the latter.q
+  // in the former case, but not the latter.
   CleanupsDepth subjectDepth = Cleanups.getCleanupsDepth();
   LexicalScope switchScope(*this, CleanupLocation(S));
   std::optional<FormalEvaluationScope> switchFormalAccess;
@@ -3562,6 +3570,10 @@ void SILGenFunction::emitSwitchStmt(SwitchStmt *S) {
   }
   case ValueOwnership::Owned: {
     // A consuming pattern match. Emit as a +1 rvalue.
+    // Create a tight evaluation scope for temporary borrows emitted during the
+    // evaluation.
+    FormalEvaluationScope limitedScope(*this);
+
     subjectMV = emitRValueAsSingleValue(S->getSubjectExpr());
     break;
   }
diff --git a/lib/SILGen/SILGenPoly.cpp b/lib/SILGen/SILGenPoly.cpp
index b7a4ca4d442a2..b2cfdcf866747 100644
--- a/lib/SILGen/SILGenPoly.cpp
+++ b/lib/SILGen/SILGenPoly.cpp
@@ -143,18 +143,16 @@ class IndirectSlot {
   }
 
   SILType getType() const {
-    if (value.is<SILValue>()) {
-      return value.get<SILValue>()->getType();
+    if (isa<SILValue>(value)) {
+      return cast<SILValue>(value)->getType();
     } else {
-      return value.get<SILType>();
+      return cast<SILType>(value);
     }
   }
 
-  bool hasAddress() const { return value.is<SILValue>(); }
+  bool hasAddress() const { return isa<SILValue>(value); }
 
-  SILValue getAddress() const {
-    return value.get<SILValue>();
-  }
+  SILValue getAddress() const { return cast<SILValue>(value); }
 
   SILValue allocate(SILGenFunction &SGF, SILLocation loc) const {
     if (hasAddress()) return getAddress();
@@ -509,7 +507,8 @@ ManagedValue Transform::transform(ManagedValue v,
   bool inputIsOptional = (bool) inputObjectType;
 
   CanType outputObjectType = outputSubstType.getOptionalObjectType();
-  bool outputIsOptional = (bool) outputObjectType;
+  bool outputIsOptional =
+      static_cast<bool>(loweredResultTy.getASTType().getOptionalObjectType());
 
   // If the value is less optional than the desired formal type, wrap in
   // an optional.
@@ -986,7 +985,8 @@ ManagedValue Transform::transformTuple(ManagedValue inputTuple,
 void SILGenFunction::collectThunkParams(
     SILLocation loc, SmallVectorImpl<ManagedValue> &params,
     SmallVectorImpl<ManagedValue> *indirectResults,
-    SmallVectorImpl<ManagedValue> *indirectErrors, ThunkGenOptions options) {
+    SmallVectorImpl<ManagedValue> *indirectErrors,
+    ManagedValue *implicitIsolation) {
   // Add the indirect results.
   for (auto resultTy : F.getConventions().getIndirectSILResultTypes(
            getTypeExpansionContext())) {
@@ -1025,12 +1025,15 @@ void SILGenFunction::collectThunkParams(
     auto functionArgument =
         B.createInputFunctionArgument(inContextParamTy, loc);
 
-    // If we are told to not propagate the isolated parameter and this is the
-    // implicit leading/isolated parameter, continue.
-    if (options.contains(ThunkGenFlag::ConvertingToNonIsolatedCaller) &&
-        param.hasOption(SILParameterInfo::ImplicitLeading) &&
-        param.hasOption(SILParameterInfo::Isolated))
+    // If our thunk has an implicit param and we are being asked to forward it,
+    // to the callee, skip it. We are going to handle it especially later.
+    if (param.hasOption(SILParameterInfo::ImplicitLeading) &&
+        param.hasOption(SILParameterInfo::Isolated)) {
+      if (implicitIsolation)
+        *implicitIsolation = functionArgument;
       continue;
+    }
+
     params.push_back(functionArgument);
   }
 }
@@ -1243,7 +1246,7 @@ class ParamInfo {
     return slot.allocate(SGF, loc);
   }
 
-  std::unique_ptr<AnyTemporaryInitialization>
+  PossiblyUniquePtr<AnyTemporaryInitialization>
   allocateForInitialization(SILGenFunction &SGF, SILLocation loc,
                             bool forceAllocation = false) {
     auto &lowering = getTypeLowering(SGF);
@@ -1259,7 +1262,7 @@ class ParamInfo {
           MarkUnresolvedNonCopyableValueInst::CheckKind::
               ConsumableAndAssignable);
     if (temporaryShouldBorrow(SGF, forceAllocation)) {
-      return std::make_unique<StoreBorrowInitialization>(address);
+      return make_possibly_unique<StoreBorrowInitialization>(address);
     }
     auto innerTemp = SGF.useBufferAsTemporary(address, lowering);
     return innerTemp;
@@ -2413,8 +2416,15 @@ class TranslateArguments : public ExpanderBase<TranslateArguments, ParamInfo> {
     return innerPackParam.getConvention();
   }
 
-  ParamInfo getInnerPackExpansionSlot(SILValue packAddr) {
-    return ParamInfo(IndirectSlot(packAddr), getInnerPackConvention());
+  ParamInfo getInnerPackExpansionSlot(ManagedValue packAddr) {
+    // Ignore the ownership of the pack address --- it'll be an
+    // l-value or r-value depending on what kind of argument we're
+    // producing, but there's no meaningful ownership yet, and in
+    // any case it won't have any cleanups attached.
+    assert(!packAddr.hasCleanup());
+
+    return ParamInfo(IndirectSlot(packAddr.getValue()),
+                     getInnerPackConvention());
   }
 
   /// Given an element of an inner pack that we're emitting into,
@@ -2767,15 +2777,29 @@ ManagedValue TranslateArguments::expandPackInnerParam(
         // cleanup onto the elements.
         auto outerComponent = outerParam.projectPackComponent(SGF, Loc);
 
-        // We can only do direct forwarding of of the pack elements in
-        // one very specific case right now.  That isn't great, but we
-        // have to live with it.
-        bool forwardouterToinner =
-          (outerExpansionTy.getPatternType()
-             == innerExpansionTy.getPatternType());
-
-        // The result of the transformation will be +1 unless we do that.
-        bool innerIsPlusOne = !forwardouterToinner;
+        bool patternTypesMatch =
+          outerExpansionTy.getPatternType() == innerExpansionTy.getPatternType();
+
+        auto innerPatternTypeIsTrivial =
+          SGF.getTypeProperties(innerExpansionTy.getPatternType()).isTrivial();
+        bool outerIsConsumed = outerComponent.hasCleanup();
+        bool innerIsConsumed =
+          isConsumedParameterInCaller(innerPackParam.getConvention());
+
+        // We can only do direct forwarding of of the pack elements (without
+        // needing temporary memory) if they have exactly the same type and
+        // we're not turning a borrowed parameter into a consuming one.
+        bool forwardOuterToInner =
+          (patternTypesMatch &&
+           (innerPatternTypeIsTrivial || outerIsConsumed || !innerIsConsumed));
+
+        // The result of the transformation function below will be +1 unless
+        // we directly forward that (or if direct forwarding produces an owned
+        // or trivial value).
+        bool innerIsPlusOne =
+          (!forwardOuterToInner ||
+           innerPatternTypeIsTrivial ||
+           outerIsConsumed);
 
         ManagedValue inner =
           SGF.emitPackTransform(Loc, outerComponent,
@@ -2784,13 +2808,18 @@ ManagedValue TranslateArguments::expandPackInnerParam(
                                 innerPackAddr,
                                 innerFormalPackType,
                                 innerComponentIndex,
-                                /*is trivial*/ forwardouterToinner,
+                                /*is simple projection*/ forwardOuterToInner,
                                 innerIsPlusOne,
             [&](ManagedValue outerEltAddr, SILType innerEltTy,
                 SGFContext ctxt) {
           // If we decided to just forward, we can do that now.
-          if (forwardouterToinner)
+          if (forwardOuterToInner) {
+            // It's okay to return an owned value here even if we're
+            // producing this for a borrowed parameter. We'll end up with
+            // an argument with cleanups, which in the end we just won't
+            // forward.
             return outerEltAddr;
+          }
 
           // Otherwise, map the subst pattern types into element context.
           CanType innerSubstEltType =
@@ -2925,8 +2954,11 @@ forwardFunctionArguments(SILGenFunction &SGF, SILLocation loc,
                          SmallVectorImpl<SILValue> &forwardedArgs,
                          SILGenFunction::ThunkGenOptions options = {}) {
   auto argTypes = fTy->getParameters();
+
+  // If our callee has an implicit parameter, we have already inserted it, so
+  // drop it from argTypes.
   if (options.contains(
-          SILGenFunction::ThunkGenFlag::ConvertingFromNonIsolatedCaller)) {
+          SILGenFunction::ThunkGenFlag::CalleeHasImplicitIsolatedParam)) {
     argTypes = argTypes.drop_front();
   }
 
@@ -3448,8 +3480,8 @@ class ResultPlanner : public ExpanderBase<ResultPlanner, IndirectSlot> {
     return temporary;
   }
 
-  IndirectSlot getInnerPackExpansionSlot(SILValue packAddr) {
-    return IndirectSlot(packAddr);
+  IndirectSlot getInnerPackExpansionSlot(ManagedValue packAddr) {
+    return IndirectSlot(packAddr.getLValueAddress());
   }
 
   IndirectSlot getInnerPackElementSlot(SILType elementTy) {
@@ -3803,8 +3835,8 @@ void ExpanderBase<Impl, InnerSlotType>::expandParallelTuples(
       ManagedValue outerPackComponent =
         outerElt.projectPackComponent(SGF, Loc);
 
-      auto innerEltSlot = asImpl().getInnerPackExpansionSlot(
-        innerElt.getPackValue().getLValueAddress());
+      auto innerEltSlot =
+        asImpl().getInnerPackExpansionSlot(innerElt.getPackValue());
       ManagedValue innerPackComponent = asImpl().expandPackExpansion(
                                 innerElt.getOrigType(),
         cast<PackExpansionType>(innerElt.getSubstType()),
@@ -4584,8 +4616,8 @@ void ExpanderBase<Impl, InnerSlotType>::expandParallelTuplesOuterIndirect(
       continue;
     }
 
-    auto innerExpansionSlot = asImpl().getInnerPackExpansionSlot(
-      innerElt.getPackValue().getLValueAddress());
+    auto innerExpansionSlot =
+      asImpl().getInnerPackExpansionSlot(innerElt.getPackValue());
     asImpl().expandPackExpansion(innerElt.getOrigType(),
          cast<PackExpansionType>(innerElt.getSubstType()),
                                  outerElt.getOrigType(),
@@ -5258,6 +5290,7 @@ void ResultPlanner::execute(SmallVectorImpl<SILValue> &innerDirectResultStack,
       LLVM_FALLTHROUGH;
     case ResultConvention::Owned:
     case ResultConvention::Autoreleased:
+    case ResultConvention::Unowned: // Handled in OwnershipModelEliminator.
       return SGF.emitManagedRValueWithCleanup(resultValue, resultTL);
     case ResultConvention::Pack:
       llvm_unreachable("shouldn't have direct result with pack results");
@@ -5267,9 +5300,10 @@ void ResultPlanner::execute(SmallVectorImpl<SILValue> &innerDirectResultStack,
       // originally 'self'.
       SGF.SGM.diagnose(Loc.getSourceLoc(), diag::not_implemented,
                        "reabstraction of returns_inner_pointer function");
-      LLVM_FALLTHROUGH;
-    case ResultConvention::Unowned:
       return SGF.emitManagedCopy(Loc, resultValue, resultTL);
+    case ResultConvention::GuaranteedAddress:
+    case ResultConvention::Guaranteed:
+      llvm_unreachable("borrow accessor not yet implemented");
     }
     llvm_unreachable("bad result convention!");
   };
@@ -5453,21 +5487,25 @@ static void buildThunkBody(SILGenFunction &SGF, SILLocation loc,
   // isolated parameter preventing us from having to memcpy over the array.
   if (outputSubstType->isAsync()) {
     if (outputSubstType->getIsolation().getKind() ==
-            FunctionTypeIsolation::Kind::NonIsolatedCaller &&
-        inputSubstType->getIsolation().getKind() !=
-            FunctionTypeIsolation::Kind::NonIsolatedCaller)
-      options |= ThunkGenFlag::ConvertingToNonIsolatedCaller;
-
-    if (outputSubstType->getIsolation().getKind() !=
-            FunctionTypeIsolation::Kind::NonIsolatedCaller &&
-        inputSubstType->getIsolation().getKind() ==
-            FunctionTypeIsolation::Kind::NonIsolatedCaller)
-      options |= ThunkGenFlag::ConvertingFromNonIsolatedCaller;
+        FunctionTypeIsolation::Kind::NonIsolatedNonsending)
+      options |= ThunkGenFlag::ThunkHasImplicitIsolatedParam;
+    if (inputSubstType->getIsolation().getKind() ==
+        FunctionTypeIsolation::Kind::NonIsolatedNonsending)
+      options |= ThunkGenFlag::CalleeHasImplicitIsolatedParam;
   }
 
+  // Collect the thunk parameters. We don't need to collect the indirect
+  // error parameter because it'll be stored as IndirectErrorResult, which
+  // gets used implicitly by emitApplyWithRethrow.
   SmallVector<ManagedValue, 8> params;
   SmallVector<ManagedValue, 4> indirectResultParams;
-  SGF.collectThunkParams(loc, params, &indirectResultParams, nullptr, options);
+  ManagedValue implicitIsolationParam;
+  SGF.collectThunkParams(loc, params, &indirectResultParams,
+                         /*indirect error params*/ nullptr,
+                         &implicitIsolationParam);
+
+  assert(bool(options & ThunkGenFlag::ThunkHasImplicitIsolatedParam)
+           == implicitIsolationParam.isValid());
 
   // Ignore the self parameter at the SIL level. IRGen will use it to
   // recover type metadata.
@@ -5485,14 +5523,16 @@ static void buildThunkBody(SILGenFunction &SGF, SILLocation loc,
     outputErasedIsolation = params.pop_back_val();
   }
 
-  if (!SGF.F.maybeGetIsolatedArgument() && argTypes.size() &&
+  if (argTypes.size() &&
       argTypes.front().hasOption(SILParameterInfo::Isolated) &&
       argTypes.front().hasOption(SILParameterInfo::ImplicitLeading))
-    options |= ThunkGenFlag::ConvertingFromNonIsolatedCaller;
+    options |= ThunkGenFlag::CalleeHasImplicitIsolatedParam;
 
-  // If we are converting to nonisolated caller, we are going to have an extra
-  // parameter in our argTypes that we need to drop.
-  if (options.contains(ThunkGenFlag::ConvertingFromNonIsolatedCaller))
+  // If we are converting from a nonisolated caller, we are going to have an
+  // extra parameter in our argTypes that we need to drop. We are going to
+  // handle it separately later so that TranslateArguments does not have to know
+  // anything about it.
+  if (options.contains(ThunkGenFlag::CalleeHasImplicitIsolatedParam))
     argTypes = argTypes.drop_front();
 
   // We may need to establish the right executor for the input function.
@@ -5503,7 +5543,7 @@ static void buildThunkBody(SILGenFunction &SGF, SILLocation loc,
   // don't need to do anything.  But if the input is synchronous and the
   // executor is asynchronous, we need to treat this like any other call
   // to a synchronous function from an asynchronous context.
-  bool hopToIsolatedParameter = false;
+  bool hopToIsolatedParameterForSync = false;
   if (outputSubstType->isAsync() && !inputSubstType->isAsync()) {
     auto inputIsolation = inputSubstType->getIsolation();
     switch (inputIsolation.getKind()) {
@@ -5511,14 +5551,16 @@ static void buildThunkBody(SILGenFunction &SGF, SILLocation loc,
     case FunctionTypeIsolation::Kind::NonIsolated:
       break;
 
-    case FunctionTypeIsolation::Kind::NonIsolatedCaller:
-      hopToIsolatedParameter = true;
-      break;
+    // For a function for caller isolation, we'll have to figure out what the
+    // output function's formal isolation is. This is quite doable, but we don't
+    // have to do it yet.
+    case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
+      llvm_unreachable("synchronous function has caller isolation?");
 
     // For a function with parameter isolation, we'll have to dig the
     // argument out after translation but before making the call.
     case FunctionTypeIsolation::Kind::Parameter:
-      hopToIsolatedParameter = true;
+      hopToIsolatedParameterForSync = true;
       break;
 
     // For a function with global-actor isolation, hop to the appropriate
@@ -5587,35 +5629,49 @@ static void buildThunkBody(SILGenFunction &SGF, SILLocation loc,
     argValues.push_back(*innerIndirectErrorAddr);
   }
 
-  // If we need to jump to an isolated parameter, do so before the call.
-  if (hopToIsolatedParameter) {
+  // If we need to jump to an isolated parameter for a synchronous function, do
+  // so before the call.
+  if (hopToIsolatedParameterForSync) {
     auto formalIsolatedIndex = getIsolatedParamIndex(inputSubstType);
     auto isolatedIndex = inputOrigType.getLoweredParamIndex(formalIsolatedIndex);
     SGF.B.createHopToExecutor(loc, args[isolatedIndex].getValue(),
                               /*mandatory*/false);
   }
 
-  // If we are thunking a nonisolated caller to nonisolated or global actor, we
-  // need to load the actor.
-  if (options.contains(ThunkGenFlag::ConvertingFromNonIsolatedCaller)) {
-    auto outputIsolation = outputSubstType->getIsolation();
-    switch (outputIsolation.getKind()) {
-    case FunctionTypeIsolation::Kind::NonIsolated:
-      argValues.push_back(SGF.emitNonIsolatedIsolation(loc).getValue());
-      break;
-    case FunctionTypeIsolation::Kind::GlobalActor: {
-      auto globalActor =
-          outputIsolation.getGlobalActorType()->getCanonicalType();
-      argValues.push_back(
-          SGF.emitGlobalActorIsolation(loc, globalActor).getValue());
-      break;
-    }
-    case FunctionTypeIsolation::Kind::Parameter:
-    case FunctionTypeIsolation::Kind::Erased:
-    case FunctionTypeIsolation::Kind::NonIsolatedCaller:
-      llvm_unreachable("Should never see this");
-      break;
-    }
+  // If the input function has caller isolation (and thus is async), we need to
+  // fill in that argument with the formal isolation of the output function and
+  // hop to it so that it is able to assume that it does not need to hop in its
+  // prologue.
+  if (options.contains(ThunkGenFlag::CalleeHasImplicitIsolatedParam)) {
+    auto forwardedIsolationValue = [&]() -> SILValue {
+      auto outputIsolation = outputSubstType->getIsolation();
+      switch (outputIsolation.getKind()) {
+      case FunctionTypeIsolation::Kind::NonIsolated:
+      case FunctionTypeIsolation::Kind::Erased:
+        // Converting a caller-isolated function to @isolated(any) makes
+        // it @concurrent. In either case, emit a nil actor reference.
+        return SGF.emitNonIsolatedIsolation(loc).getValue();
+      case FunctionTypeIsolation::Kind::GlobalActor: {
+        auto globalActor =
+            outputIsolation.getGlobalActorType()->getCanonicalType();
+        return SGF.emitGlobalActorIsolation(loc, globalActor).getValue();
+      }
+      case FunctionTypeIsolation::Kind::NonIsolatedNonsending: {
+        return implicitIsolationParam.getValue();
+      }
+      case FunctionTypeIsolation::Kind::Parameter:
+        // This would require a conversion from a type with caller
+        // isolation to a type with parameter isolation, which is not
+        // currently allowed and probably won't ever be. Anyway, to
+        // implement it, we'd need to borrow the isolated parameter
+        // and wrap it up as an `Optional<any Actor>`.
+        llvm::report_fatal_error("Should never see this?!");
+      }
+    }();
+
+    assert(forwardedIsolationValue);
+    SGF.B.createHopToExecutor(loc, forwardedIsolationValue, false);
+    argValues.push_back(forwardedIsolationValue);
   }
 
   // Add the rest of the arguments.
@@ -5624,6 +5680,16 @@ static void buildThunkBody(SILGenFunction &SGF, SILLocation loc,
   auto fun = fnType->isCalleeGuaranteed() ? fnValue.borrow(SGF, loc).getValue()
                                           : fnValue.forward(SGF);
 
+  // If our thunk is a caller isolated function, we need to insert a hop to
+  // return to our isolation so that our caller can assume that we preserve
+  // isolation.
+  if (auto isolatedArg = llvm::cast_or_null<SILFunctionArgument>(
+          SGF.F.maybeGetIsolatedArgument());
+      isolatedArg && isolatedArg->getKnownParameterInfo().hasOption(
+                         SILParameterInfo::ImplicitLeading)) {
+    SGF.emitScopedHopToTargetActor(loc, isolatedArg);
+  }
+
   SILValue innerResult =
       SGF.emitApplyWithRethrow(loc, fun,
                                /*substFnType*/ fnValue.getType(),
@@ -5965,7 +6031,9 @@ static void buildWithoutActuallyEscapingThunkBody(SILGenFunction &SGF,
   SmallVector<ManagedValue, 8> params;
   SmallVector<ManagedValue, 8> indirectResults;
   SmallVector<ManagedValue, 1> indirectErrorResults;
-  SGF.collectThunkParams(loc, params, &indirectResults, &indirectErrorResults);
+  ManagedValue implicitIsolationParam;
+  SGF.collectThunkParams(loc, params, &indirectResults, &indirectErrorResults,
+                         &implicitIsolationParam);
 
   // Ignore the self parameter at the SIL level. IRGen will use it to
   // recover type metadata.
@@ -5986,6 +6054,11 @@ static void buildWithoutActuallyEscapingThunkBody(SILGenFunction &SGF,
   for (auto indirectError : indirectErrorResults)
     argValues.push_back(indirectError.getLValueAddress());
 
+  // Forward the implicit isolation parameter.
+  if (implicitIsolationParam.isValid()) {
+    argValues.push_back(implicitIsolationParam.getValue());
+  }
+
    // Add the rest of the arguments.
   forwardFunctionArguments(SGF, loc, fnType, params, argValues);
 
@@ -6175,6 +6248,7 @@ ManagedValue SILGenFunction::getThunkedAutoDiffLinearMap(
     return getThunkedResult();
   thunk->setGenericEnvironment(genericEnv);
 
+  // FIXME: handle implicit isolation parameter here
   SILGenFunction thunkSGF(SGM, *thunk, FunctionDC);
   SmallVector<ManagedValue, 4> params;
   SmallVector<ManagedValue, 4> thunkIndirectResults;
@@ -6499,8 +6573,14 @@ SILFunction *SILGenModule::getOrCreateCustomDerivativeThunk(
   auto loc = customDerivativeFn->getLocation();
   SILGenFunctionBuilder fb(*this);
   // Derivative thunks have the same linkage as the original function, stripping
-  // external.
-  auto linkage = stripExternalFromLinkage(originalFn->getLinkage());
+  // external. For @_alwaysEmitIntoClient original functions, force PublicNonABI
+  // linkage of derivative thunks so we can serialize them (the original
+  // function itself might be HiddenExternal in this case if we only have
+  // declaration without definition).
+  auto linkage = originalFn->markedAsAlwaysEmitIntoClient()
+                     ? SILLinkage::PublicNonABI
+                     : stripExternalFromLinkage(originalFn->getLinkage());
+
   auto *thunk = fb.getOrCreateFunction(
       loc, name, linkage, thunkFnTy, IsBare, IsNotTransparent,
       customDerivativeFn->getSerializedKind(),
@@ -6511,12 +6591,13 @@ SILFunction *SILGenModule::getOrCreateCustomDerivativeThunk(
       customDerivativeFn->getClassSubclassScope());
   // This thunk may be publicly exposed and cannot be transparent.
   // Instead, mark it as "always inline" for optimization.
-  thunk->setInlineStrategy(AlwaysInline);
+  thunk->setInlineStrategy(HeuristicAlwaysInline);
   if (!thunk->empty())
     return thunk;
   thunk->setGenericEnvironment(thunkGenericEnv);
 
   SILGenFunction thunkSGF(*this, *thunk, customDerivativeFn->getDeclContext());
+  // FIXME: handle implicit isolation parameter here
   SmallVector<ManagedValue, 4> params;
   SmallVector<ManagedValue, 4> indirectResults;
   SmallVector<ManagedValue, 1> indirectErrorResults;
@@ -6946,10 +7027,6 @@ SILGenFunction::emitVTableThunk(SILDeclRef base,
   cleanupLoc.markAutoGenerated();
   Scope scope(Cleanups, cleanupLoc);
 
-  SmallVector<ManagedValue, 8> thunkArgs;
-  SmallVector<ManagedValue, 8> thunkIndirectResults;
-  collectThunkParams(loc, thunkArgs, &thunkIndirectResults);
-
   CanSILFunctionType derivedFTy;
   if (baseLessVisibleThanDerived) {
     derivedFTy =
@@ -6974,16 +7051,41 @@ SILGenFunction::emitVTableThunk(SILDeclRef base,
             ->substGenericArgs(subs)->getCanonicalType());
   }
 
-  // Emit the indirect return and arguments.
   auto thunkTy = F.getLoweredFunctionType();
 
-  SmallVector<ManagedValue, 8> substArgs;
+  using ThunkGenFlag = SILGenFunction::ThunkGenFlag;
+  auto options = SILGenFunction::ThunkGenOptions();
+
+  {
+    auto thunkIsolatedParam = thunkTy->maybeGetIsolatedParameter();
+    if (thunkIsolatedParam &&
+        thunkIsolatedParam->hasOption(SILParameterInfo::ImplicitLeading))
+      options |= ThunkGenFlag::ThunkHasImplicitIsolatedParam;
+    auto derivedIsolatedParam = derivedFTy->maybeGetIsolatedParameter();
+    if (derivedIsolatedParam &&
+        derivedIsolatedParam->hasOption(SILParameterInfo::ImplicitLeading))
+      options |= ThunkGenFlag::CalleeHasImplicitIsolatedParam;
+  }
+
+  SmallVector<ManagedValue, 8> thunkArgs;
+  SmallVector<ManagedValue, 8> thunkIndirectResults;
+  collectThunkParams(loc, thunkArgs, &thunkIndirectResults);
 
+  // Emit the indirect return and arguments.
+  SmallVector<ManagedValue, 8> substArgs;
   AbstractionPattern outputOrigType(outputSubstType);
 
+  auto derivedFTyParamInfo = derivedFTy->getParameters();
+
+  // If we are transforming to a callee with an implicit param, drop the
+  // implicit param so that we can insert it again later. This ensures
+  // TranslateArguments does not need to know about this.
+  if (options.contains(ThunkGenFlag::CalleeHasImplicitIsolatedParam))
+    derivedFTyParamInfo = derivedFTyParamInfo.drop_front();
+
   // Reabstract the arguments.
   TranslateArguments(*this, loc, thunkArgs, substArgs,
-                     derivedFTy, derivedFTy->getParameters())
+                     derivedFTy, derivedFTyParamInfo)
     .process(outputOrigType,
              outputSubstType.getParams(),
              inputOrigType,
@@ -7013,8 +7115,77 @@ SILGenFunction::emitVTableThunk(SILDeclRef base,
     }
   }
 
+  // Now that we have translated arguments and inserted our thunk indirect
+  // parameters... before we forward those arguments, insert the implicit
+  // leading parameter.
+  if (options.contains(ThunkGenFlag::CalleeHasImplicitIsolatedParam)) {
+    auto baseIsolation =
+        swift::getActorIsolation(base.getAbstractFunctionDecl());
+    std::optional<ActorIsolation> derivedIsolationCache;
+    auto getDerivedIsolation = [&]() -> ActorIsolation {
+      if (!derivedIsolationCache) {
+        derivedIsolationCache =
+            swift::getActorIsolation(derived.getAbstractFunctionDecl());
+      }
+      return *derivedIsolationCache;
+    };
+
+    switch (baseIsolation) {
+    case ActorIsolation::Unspecified:
+    case ActorIsolation::Nonisolated:
+    case ActorIsolation::NonisolatedUnsafe:
+      args.push_back(emitNonIsolatedIsolation(loc).getValue());
+      break;
+    case ActorIsolation::Erased:
+      llvm::report_fatal_error("Found erased actor isolation?!");
+      break;
+    case ActorIsolation::GlobalActor: {
+      auto globalActor = baseIsolation.getGlobalActor()->getCanonicalType();
+      args.push_back(emitGlobalActorIsolation(loc, globalActor).getValue());
+      break;
+    }
+    case ActorIsolation::ActorInstance:
+    case ActorIsolation::CallerIsolationInheriting: {
+      auto derivedIsolation = getDerivedIsolation();
+      switch (derivedIsolation) {
+      case ActorIsolation::Unspecified:
+      case ActorIsolation::Nonisolated:
+      case ActorIsolation::NonisolatedUnsafe:
+        args.push_back(emitNonIsolatedIsolation(loc).getValue());
+        break;
+      case ActorIsolation::Erased:
+        llvm::report_fatal_error("Found erased actor isolation?!");
+        break;
+      case ActorIsolation::GlobalActor: {
+        auto globalActor =
+            derivedIsolation.getGlobalActor()->getCanonicalType();
+        args.push_back(emitGlobalActorIsolation(loc, globalActor).getValue());
+        break;
+      }
+      case ActorIsolation::ActorInstance:
+      case ActorIsolation::CallerIsolationInheriting: {
+        auto isolatedArg = F.maybeGetIsolatedArgument();
+        assert(isolatedArg);
+        args.push_back(isolatedArg);
+        break;
+      }
+      }
+      break;
+    }
+    }
+
+    // If our derived isolation is caller isolation inheriting and our base
+    // isn't, we need to insert a hop so that derived can assume that it does
+    // not have to hop in its prologue.
+    if (!baseIsolation.isCallerIsolationInheriting() &&
+        getDerivedIsolation().isCallerIsolationInheriting()) {
+      B.createHopToExecutor(loc, args.back(), false /*mandatory*/);
+    }
+  }
+
   // Then, the arguments.
-  forwardFunctionArguments(*this, loc, derivedFTy, substArgs, args);
+  forwardFunctionArguments(*this, loc, derivedFTy, substArgs, args,
+                           options);
 
   // Create the call.
   SILValue derivedRef;
@@ -7028,6 +7199,15 @@ SILGenFunction::emitVTableThunk(SILDeclRef base,
     derivedRef = B.createFunctionRefFor(loc, implFn);
   }
 
+  // Check if our base was caller isolation inheriting. In such a case, we need
+  // to insert a hop back to our original actor.
+  if (auto isolatedArg = llvm::dyn_cast_or_null<SILFunctionArgument>(
+          F.maybeGetIsolatedArgument());
+      isolatedArg && isolatedArg->getKnownParameterInfo().hasOption(
+                         SILParameterInfo::ImplicitLeading)) {
+    emitScopedHopToTargetActor(loc, {isolatedArg});
+  }
+
   SILValue result;
 
   switch (coroutineKind) {
@@ -7046,8 +7226,8 @@ SILGenFunction::emitVTableThunk(SILDeclRef base,
   case SILCoroutineKind::YieldOnce2: {
     SmallVector<SILValue, 4> derivedYields;
     auto tokenAndCleanups = emitBeginApplyWithRethrow(
-        loc, derivedRef, SILType::getPrimitiveObjectType(derivedFTy), subs,
-        args, derivedYields);
+        loc, derivedRef, SILType::getPrimitiveObjectType(derivedFTy),
+        canUnwindAccessorDeclRef(base), subs, args, derivedYields);
     auto token = std::get<0>(tokenAndCleanups);
     auto abortCleanup = std::get<1>(tokenAndCleanups);
     auto allocation = std::get<2>(tokenAndCleanups);
@@ -7078,7 +7258,7 @@ SILGenFunction::emitVTableThunk(SILDeclRef base,
     result = B.createTuple(loc, {});
     break;
   }
-  
+
   scope.pop();
   B.createReturn(loc, result);
 
@@ -7264,8 +7444,57 @@ void SILGenFunction::emitProtocolWitness(
   FullExpr scope(Cleanups, cleanupLoc);
   FormalEvaluationScope formalEvalScope(*this);
 
+  // Grab the type of our thunk.
   auto thunkTy = F.getLoweredFunctionType();
 
+  // Then get the type of the witness.
+  auto witnessKind = getWitnessDispatchKind(witness, isSelfConformance);
+  auto witnessInfo = getConstantInfo(getTypeExpansionContext(), witness);
+  CanAnyFunctionType witnessSubstTy = witnessInfo.LoweredType;
+  if (auto genericFnType = dyn_cast<GenericFunctionType>(witnessSubstTy)) {
+    witnessSubstTy = cast<FunctionType>(
+        genericFnType->substGenericArgs(witnessSubs)->getCanonicalType());
+  }
+
+  assert(!witnessSubstTy->hasError());
+
+  if (auto genericFnType = dyn_cast<GenericFunctionType>(reqtSubstTy)) {
+    auto forwardingSubs = F.getForwardingSubstitutionMap();
+    reqtSubstTy = cast<FunctionType>(
+        genericFnType->substGenericArgs(forwardingSubs)->getCanonicalType());
+  } else {
+    reqtSubstTy = cast<FunctionType>(
+        F.mapTypeIntoContext(reqtSubstTy)->getCanonicalType());
+  }
+
+  assert(!reqtSubstTy->hasError());
+
+  // Get the lowered type of the witness.
+  auto origWitnessFTy = getWitnessFunctionType(getTypeExpansionContext(), SGM,
+                                               witness, witnessKind);
+  auto witnessFTy = origWitnessFTy;
+  if (!witnessSubs.empty()) {
+    witnessFTy = origWitnessFTy->substGenericArgs(SGM.M, witnessSubs,
+                                                  getTypeExpansionContext());
+  }
+
+  // Now that we have the type information in hand, we can generate the thunk
+  // body.
+
+  using ThunkGenFlag = SILGenFunction::ThunkGenFlag;
+  auto options = SILGenFunction::ThunkGenOptions();
+
+  {
+    auto thunkIsolatedParam = thunkTy->maybeGetIsolatedParameter();
+    if (thunkIsolatedParam &&
+        thunkIsolatedParam->hasOption(SILParameterInfo::ImplicitLeading))
+      options |= ThunkGenFlag::ThunkHasImplicitIsolatedParam;
+    auto witnessIsolatedParam = witnessFTy->maybeGetIsolatedParameter();
+    if (witnessIsolatedParam &&
+        witnessIsolatedParam->hasOption(SILParameterInfo::ImplicitLeading))
+      options |= ThunkGenFlag::CalleeHasImplicitIsolatedParam;
+  }
+
   SmallVector<ManagedValue, 8> origParams;
   SmallVector<ManagedValue, 8> thunkIndirectResults;
   collectThunkParams(loc, origParams, &thunkIndirectResults);
@@ -7280,7 +7509,7 @@ void SILGenFunction::emitProtocolWitness(
 
     // For an instance actor, get the actor 'self'.
     if (*enterIsolation == ActorIsolation::ActorInstance) {
-      assert(enterIsolation->getActorInstanceParameter() == 0 && "Not self?");
+      assert(enterIsolation->isActorInstanceForSelfParameter() && "Not self?");
       auto actorSelfVal = origParams.back();
 
       if (actorSelfVal.getType().isAddress()) {
@@ -7305,40 +7534,7 @@ void SILGenFunction::emitProtocolWitness(
     }
   }
 
-  // Get the type of the witness.
-  auto witnessKind = getWitnessDispatchKind(witness, isSelfConformance);
-  auto witnessInfo = getConstantInfo(getTypeExpansionContext(), witness);
-  CanAnyFunctionType witnessSubstTy = witnessInfo.LoweredType;
-  if (auto genericFnType = dyn_cast<GenericFunctionType>(witnessSubstTy)) {
-    witnessSubstTy = cast<FunctionType>(genericFnType
-                                          ->substGenericArgs(witnessSubs)
-                                          ->getCanonicalType());
-  }
-
-  assert(!witnessSubstTy->hasError());
-
-  if (auto genericFnType = dyn_cast<GenericFunctionType>(reqtSubstTy)) {
-    auto forwardingSubs = F.getForwardingSubstitutionMap();
-    reqtSubstTy = cast<FunctionType>(genericFnType
-                                          ->substGenericArgs(forwardingSubs)
-                                          ->getCanonicalType());
-  } else {
-    reqtSubstTy = cast<FunctionType>(F.mapTypeIntoContext(reqtSubstTy)
-                                          ->getCanonicalType());
-  }
-
-  assert(!reqtSubstTy->hasError());
-
-  // Get the lowered type of the witness.
-  auto origWitnessFTy = getWitnessFunctionType(getTypeExpansionContext(), SGM,
-                                               witness, witnessKind);
-  auto witnessFTy = origWitnessFTy;
-  if (!witnessSubs.empty()) {
-    witnessFTy = origWitnessFTy->substGenericArgs(SGM.M, witnessSubs,
-                                                  getTypeExpansionContext());
-  }
   auto witnessUnsubstTy = witnessFTy->getUnsubstitutedType(SGM.M);
-
   auto reqtSubstParams = reqtSubstTy.getParams();
   auto witnessSubstParams = witnessSubstTy.getParams();
 
@@ -7360,8 +7556,8 @@ void SILGenFunction::emitProtocolWitness(
   //    @convention(c) () -> ()
   // . We do this by simply omitting the last params.
   // TODO: fix this for static C++ methods.
-  if (witness.getDecl()->getClangDecl() &&
-      isa<clang::CXXConstructorDecl>(witness.getDecl()->getClangDecl())) {
+  if (isa_and_nonnull<clang::CXXConstructorDecl>(
+          witness.getDecl()->getClangDecl())) {
     origParams.pop_back();
     reqtSubstParams = reqtSubstParams.drop_back();
     ignoreFinalInputOrigParam = true;
@@ -7379,15 +7575,19 @@ void SILGenFunction::emitProtocolWitness(
   // Translate the argument values from the requirement abstraction level to
   // the substituted signature of the witness.
   SmallVector<ManagedValue, 8> witnessParams;
+  auto witnessParamInfos = witnessUnsubstTy->getParameters();
+
+  // If we are transforming to a callee with an implicit param, drop the
+  // implicit param so that we can insert it again later. This ensures
+  // TranslateArguments does not need to know about this.
+  if (options.contains(ThunkGenFlag::CalleeHasImplicitIsolatedParam))
+    witnessParamInfos = witnessParamInfos.drop_front();
+
   AbstractionPattern witnessOrigTy(witnessInfo.LoweredType);
-  TranslateArguments(*this, loc,
-                     origParams, witnessParams,
-                     witnessUnsubstTy, witnessUnsubstTy->getParameters())
-    .process(witnessOrigTy,
-             witnessSubstParams,
-             reqtOrigTy,
-             reqtSubstParams,
-             ignoreFinalInputOrigParam);
+  TranslateArguments(*this, loc, origParams, witnessParams, witnessUnsubstTy,
+                     witnessParamInfos)
+      .process(witnessOrigTy, witnessSubstParams, reqtOrigTy, reqtSubstParams,
+               ignoreFinalInputOrigParam);
 
   SILValue witnessFnRef = getWitnessFunctionRef(*this, witness,
                                                 origWitnessFTy,
@@ -7420,8 +7620,87 @@ void SILGenFunction::emitProtocolWitness(
     }
   }
 
+  // Now that we have translated arguments and inserted our thunk indirect
+  // parameters... before we forward those arguments, insert the implicit
+  // leading parameter.
+  if (options.contains(ThunkGenFlag::CalleeHasImplicitIsolatedParam)) {
+    auto reqtIsolation =
+        swift::getActorIsolation(requirement.getAbstractFunctionDecl());
+    std::optional<ActorIsolation> witnessIsolationCache;
+    auto getWitnessIsolation = [&]() -> ActorIsolation {
+      if (!witnessIsolationCache) {
+        witnessIsolationCache =
+            swift::getActorIsolation(witness.getAbstractFunctionDecl());
+      }
+      return *witnessIsolationCache;
+    };
+    switch (reqtIsolation) {
+    case ActorIsolation::Unspecified:
+    case ActorIsolation::Nonisolated:
+    case ActorIsolation::NonisolatedUnsafe:
+      args.push_back(emitNonIsolatedIsolation(loc).getValue());
+      break;
+    case ActorIsolation::Erased:
+      llvm::report_fatal_error("Found erased actor isolation?!");
+      break;
+    case ActorIsolation::GlobalActor: {
+      auto globalActor = reqtIsolation.getGlobalActor()->getCanonicalType();
+      args.push_back(emitGlobalActorIsolation(loc, globalActor).getValue());
+      break;
+    }
+    case ActorIsolation::ActorInstance:
+    case ActorIsolation::CallerIsolationInheriting: {
+      auto witnessIsolation = getWitnessIsolation();
+      switch (witnessIsolation) {
+      case ActorIsolation::Unspecified:
+      case ActorIsolation::Nonisolated:
+      case ActorIsolation::NonisolatedUnsafe:
+        args.push_back(emitNonIsolatedIsolation(loc).getValue());
+        break;
+      case ActorIsolation::Erased:
+        llvm::report_fatal_error("Found erased actor isolation?!");
+        break;
+      case ActorIsolation::GlobalActor: {
+        auto globalActor =
+            witnessIsolation.getGlobalActor()->getCanonicalType();
+        args.push_back(emitGlobalActorIsolation(loc, globalActor).getValue());
+        break;
+      }
+      case ActorIsolation::ActorInstance:
+      case ActorIsolation::CallerIsolationInheriting: {
+        auto isolatedArg = F.maybeGetIsolatedArgument();
+        assert(isolatedArg);
+        args.push_back(isolatedArg);
+        break;
+      }
+      }
+      break;
+    }
+    }
+
+    // If our reqtIsolation was not caller isolation inheriting, but our witness
+    // isolation is caller isolation inheriting, hop onto the reqtIsolation so
+    // that it is safe for our witness to assume that it is already on its
+    // actor.
+    if (!reqtIsolation.isCallerIsolationInheriting() &&
+        getWitnessIsolation().isCallerIsolationInheriting()) {
+      B.createHopToExecutor(loc, args.back(), false /*mandatory*/);
+    }
+  }
+
+  // Check if our caller has an implicit isolated param. If so, we need to
+  // insert a hop at the end of the function to ensure that our caller can
+  // assume that we are going to be on its isolation.
+  if (auto isolatedArg =
+          cast_or_null<SILFunctionArgument>(F.maybeGetIsolatedArgument());
+      isolatedArg && isolatedArg->getKnownParameterInfo().hasOption(
+                         SILParameterInfo::ImplicitLeading)) {
+    emitScopedHopToTargetActor(loc, SILValue(isolatedArg));
+  }
+
   //   - the rest of the arguments
-  forwardFunctionArguments(*this, loc, witnessFTy, witnessParams, args);
+  forwardFunctionArguments(*this, loc, witnessFTy, witnessParams, args,
+                           options);
 
   // Perform the call.
   SILType witnessSILTy = SILType::getPrimitiveObjectType(witnessFTy);
@@ -7441,7 +7720,8 @@ void SILGenFunction::emitProtocolWitness(
   case SILCoroutineKind::YieldOnce2: {
     SmallVector<SILValue, 4> witnessYields;
     auto tokenAndCleanups = emitBeginApplyWithRethrow(
-        loc, witnessFnRef, witnessSILTy, witnessSubs, args, witnessYields);
+        loc, witnessFnRef, witnessSILTy, canUnwindAccessorDeclRef(requirement),
+        witnessSubs, args, witnessYields);
     auto token = std::get<0>(tokenAndCleanups);
     auto abortCleanup = std::get<1>(tokenAndCleanups);
     auto allocation = std::get<2>(tokenAndCleanups);
diff --git a/lib/SILGen/SILGenProlog.cpp b/lib/SILGen/SILGenProlog.cpp
index 708e12c5e381a..d5590ca1cf557 100644
--- a/lib/SILGen/SILGenProlog.cpp
+++ b/lib/SILGen/SILGenProlog.cpp
@@ -92,7 +92,7 @@ struct LoweredParamGenerator {
                         unsigned numIgnoredTrailingParameters)
     : SGF(SGF), fnTy(SGF.F.getLoweredFunctionType()),
       parameterTypes(
-          SGF.F.getLoweredFunctionTypeInContext(SGF.B.getTypeExpansionContext())
+          SGF.F.getLoweredFunctionTypeInContext()
               ->getParameters().drop_back(numIgnoredTrailingParameters)) {}
 
   ParamDecl *paramDecl = nullptr;
@@ -631,7 +631,6 @@ class ArgumentInitHelper {
   std::optional<FunctionInputGenerator> FormalParamTypes;
 
   SmallPtrSet<ParamDecl *, 2> ScopedDependencies;
-  SmallPtrSet<ParamDecl *, 2> AddressableParams;
 
 public:
   ArgumentInitHelper(SILGenFunction &SGF,
@@ -729,16 +728,15 @@ class ArgumentInitHelper {
                                         : AbstractionPattern(substType));
 
       // A parameter can be directly marked as addressable, or its
-      // addressability can be implied by a scoped dependency.
-      bool isAddressable = false;
-      
-      isAddressable = pd->isAddressable()
-        || (ScopedDependencies.contains(pd)
-            && SGF.getTypeLowering(origType, substType)
-                  .getRecursiveProperties().isAddressableForDependencies());
-      if (isAddressable) {
-        AddressableParams.insert(pd);
-      }
+      // addressability can be implied by a scoped dependency or a borrow
+      // dependency.
+      bool isAddressable =
+          pd->isAddressable() ||
+          (ScopedDependencies.contains(pd) &&
+           SGF.getTypeProperties(origType, substType)
+               .isAddressableForDependencies()) ||
+          SGF.getFunction().getConventions().hasGuaranteedAddressResult() ||
+          SGF.getFunction().getConventions().hasGuaranteedResult();
       paramValue = argEmitter.handleParam(origType, substType, pd,
                                           isAddressable);
     }
@@ -793,6 +791,10 @@ class ArgumentInitHelper {
         }
       }
     }
+    // If we're relying on ManualOwnership for explicit-copies enforcement,
+    // we don't need @noImplicitCopy / MoveOnlyWrapper.
+    if (SGF.B.hasManualOwnershipAttr())
+      isNoImplicitCopy = false;
 
     // If we have a no implicit copy argument and the argument is trivial,
     // we need to use copyable to move only to convert it to its move only
@@ -902,6 +904,8 @@ class ArgumentInitHelper {
     ManagedValue argrv = makeArgument(loc, pd);
     if (pd->isInOut()) {
       assert(argrv.getType().isAddress() && "expected inout to be address");
+    } else if (argrv.getType().is<SILPackType>()) {
+      assert(argrv.getType().isAddress() && "expected pack to be address");
     } else if (!pd->isImmutableInFunctionBody()) {
       // If it's a locally mutable parameter, then we need to move the argument
       // value into a local box to hold the mutated value.
@@ -1214,8 +1218,9 @@ static void emitCaptureArguments(SILGenFunction &SGF,
   SILType ty = lowering.getLoweredType();
 
   bool isNoImplicitCopy;
-  
-  if (ty.isTrivial(SGF.F) || ty.isMoveOnly()) {
+
+  if (ty.isTrivial(SGF.F) || ty.isMoveOnly() ||
+      SGF.B.hasManualOwnershipAttr()) {
     isNoImplicitCopy = false;
   } else if (VD->isNoImplicitCopy()) {
     isNoImplicitCopy = true;
@@ -1406,6 +1411,7 @@ static void emitCaptureArguments(SILGenFunction &SGF,
   }
 
   SGF.VarLocs[VD] = SILGenFunction::VarLoc(arg, enforcement, box);
+  SGF.enterLocalVariableAddressableBufferScope(VD);
   SILDebugVariable DbgVar(VD->isLet(), ArgNo);
   if (auto *AllocStack = dyn_cast<AllocStackInst>(arg)) {
     AllocStack->setArgNo(ArgNo);
@@ -1534,6 +1540,13 @@ static void emitIndirectResultParameters(SILGenFunction &SGF,
                                          Type resultType,
                                          AbstractionPattern origResultType,
                                          DeclContext *DC) {
+  // Borrow and mutate accessors do not return indirectly.
+  if (auto *accessor = dyn_cast<AccessorDecl>(DC)) {
+    if (accessor->isBorrowAccessor() || accessor->isMutateAccessor()) {
+      return;
+    }
+  }
+
   CanType resultTypeInContext =
     DC->mapTypeIntoContext(resultType)->getCanonicalType();
 
@@ -1655,7 +1668,8 @@ uint16_t SILGenFunction::emitBasicProlog(
   emitIndirectResultParameters(*this, resultType, origResultType, DC);
 
   std::optional<AbstractionPattern> origErrorType;
-  if (origClosureType && !origClosureType->isTypeParameterOrOpaqueArchetype()) {
+  if (origClosureType && !origClosureType->isTypeParameterOrOpaqueArchetype() &&
+      !origClosureType->isClangType()) {
     origErrorType = origClosureType->getFunctionThrownErrorType();
     if (origErrorType && !errorType)
       errorType = origErrorType->getEffectiveThrownErrorType();
diff --git a/lib/SILGen/SILGenRequests.cpp b/lib/SILGen/SILGenRequests.cpp
index 143d987d69a01..9eaf99f705046 100644
--- a/lib/SILGen/SILGenRequests.cpp
+++ b/lib/SILGen/SILGenRequests.cpp
@@ -52,12 +52,12 @@ evaluator::DependencySource ASTLoweringRequest::readDependencySource(
   auto &desc = std::get<0>(getStorage());
 
   // We don't track dependencies in whole-module mode.
-  if (desc.context.is<ModuleDecl *>()) {
+  if (isa<ModuleDecl *>(desc.context)) {
     return nullptr;
   }
 
   // If we have a single source file, it's the source of dependencies.
-  return dyn_cast<SourceFile>(desc.context.get<FileUnit *>());
+  return dyn_cast<SourceFile>(cast<FileUnit *>(desc.context));
 }
 
 ArrayRef<FileUnit *> ASTLoweringDescriptor::getFilesToEmit() const {
diff --git a/lib/SILGen/SILGenStmt.cpp b/lib/SILGen/SILGenStmt.cpp
index 88db501de104a..0d9369469576a 100644
--- a/lib/SILGen/SILGenStmt.cpp
+++ b/lib/SILGen/SILGenStmt.cpp
@@ -20,13 +20,15 @@
 #include "RValue.h"
 #include "SILGen.h"
 #include "Scope.h"
+#include "StorageRefResult.h"
 #include "SwitchEnumBuilder.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/DiagnosticsSIL.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/ProfileCounter.h"
-#include "swift/SIL/BasicBlockUtils.h"
 #include "swift/SIL/AbstractionPatternGenerators.h"
+#include "swift/SIL/BasicBlockUtils.h"
+#include "swift/SIL/InstructionUtils.h"
 #include "swift/SIL/SILArgument.h"
 #include "swift/SIL/SILProfiler.h"
 #include "llvm/Support/SaveAndRestore.h"
@@ -427,7 +429,7 @@ void StmtEmitter::visitBraceStmt(BraceStmt *S) {
     } else if (auto *E = ESD.dyn_cast<Expr*>()) {
       SGF.emitIgnoredExpr(E);
     } else {
-      auto *D = ESD.get<Decl*>();
+      auto *D = cast<Decl *>(ESD);
       assert((isa<PatternBindingDecl>(D) || isa<VarDecl>(D)) &&
              "other decls should be handled before the reachability check");
       SGF.visit(D);
@@ -482,7 +484,7 @@ createIndirectResultInit(SILGenFunction &SGF, SILValue addr,
   if (cleanup.isValid())
     cleanups.push_back(cleanup);
 
-  return InitializationPtr(temporary.release());
+  return temporary;
 }
 
 static InitializationPtr
@@ -668,7 +670,7 @@ prepareIndirectResultInit(SILGenFunction &SGF, SILLocation loc,
 ///   components of the result
 /// \param cleanups - will be filled (after initialization completes)
 ///   with all the active cleanups managing the result values
-std::unique_ptr<Initialization>
+InitializationPtr
 SILGenFunction::prepareIndirectResultInit(
                                  SILLocation loc,
                                  AbstractionPattern origResultType,
@@ -698,6 +700,172 @@ SILGenFunction::prepareIndirectResultInit(
   return init;
 }
 
+static Expr *lookThroughProjections(Expr *expr) {
+  auto *lookupExpr = dyn_cast<LookupExpr>(expr);
+  if (!lookupExpr) {
+    return expr;
+  }
+  return lookThroughProjections(lookupExpr->getBase());
+}
+
+SILValue SILGenFunction::emitUncheckedGuaranteedConversion(SILValue value) {
+  assert(value->getType().isObject());
+  assert(F.getConventions().hasGuaranteedResult());
+  auto regularLoc = RegularLocation::getAutoGeneratedLocation();
+  // Introduce a pair of unchecked_ownership_conversion instructions to
+  // avoid ownership errors from returning a load borrowed value.
+  // TODO: Introduce new SIL semantics to allow returning borrowed
+  // values from within a local borrow scope.
+  auto result = B.createUncheckedOwnershipConversion(regularLoc, value,
+                                                     OwnershipKind::Unowned);
+  result = B.createUncheckedOwnershipConversion(regularLoc, result,
+                                                OwnershipKind::Guaranteed);
+  return result;
+}
+
+bool SILGenFunction::emitGuaranteedReturn(
+    SILLocation loc, Expr *ret, SmallVectorImpl<SILValue> &directResults) {
+  auto *afd = cast<AbstractFunctionDecl>(FunctionDC->getAsDecl());
+  assert(cast<AccessorDecl>(afd)->isBorrowAccessor() ||
+         cast<AccessorDecl>(afd)->isMutateAccessor());
+
+  auto emitLoadBorrowFromGuaranteedAddress =
+      [&](ManagedValue guaranteedAddress) -> SILValue {
+    assert(guaranteedAddress.getValue()->getType().isAddress());
+    assert(F.getConventions().hasGuaranteedResult());
+    auto regularLoc = RegularLocation::getAutoGeneratedLocation();
+    auto load =
+        B.createLoadBorrow(regularLoc, guaranteedAddress).getValue();
+    return emitUncheckedGuaranteedConversion(load);
+  };
+
+  // If the return expression is a literal, emit as a regular return
+  // expression.
+  if (isa<LiteralExpr>(ret)) {
+    auto RV = emitRValue(ret);
+    std::move(RV).forwardAll(*this, directResults);
+    return false;
+  }
+
+  auto storageRefResult =
+      StorageRefResult::findStorageReferenceExprForBorrow(ret);
+  auto lvExpr = storageRefResult.getTransitiveRoot();
+  // If the return expression is not an lvalue, diagnose.
+  if (!lvExpr) {
+    diagnose(getASTContext(), ret->getStartLoc(),
+             diag::invalid_borrow_accessor_return);
+    diagnose(getASTContext(), ret->getStartLoc(),
+             diag::borrow_accessor_not_a_projection_note);
+    return true;
+  }
+
+  // Emit return value at +0.
+  FormalEvaluationScope scope(*this);
+  LValueOptions options;
+
+  if (cast<AccessorDecl>(afd)->isMutateAccessor()) {
+    options = options.forGuaranteedAddressReturn(true);
+  } else {
+    assert(cast<AccessorDecl>(afd)->isBorrowAccessor());
+    if (F.getSelfArgument()->getType().isObject()) {
+      options = options.forGuaranteedReturn(true);
+    } else {
+      options = options.forGuaranteedAddressReturn(true);
+    }
+  }
+
+  auto lvalue = emitLValue(ret,
+                           F.getSelfArgument()->getType().isObject()
+                               ? SGFAccessKind::BorrowedObjectRead
+                           : cast<AccessorDecl>(afd)->isBorrowAccessor()
+                               ? SGFAccessKind::BorrowedAddressRead
+                               : SGFAccessKind::Write,
+                           options);
+
+  // If the accessor is annotated with @_unsafeSelfDependentResultAttr,
+  // disable diagnosing the return expression.
+  // If the accessor is annotated with @_unsafeSelfDependentResultAttr,
+  // disable diagnosing the return expression.
+  // This is needed to implement borrow accessors for Unsafe*Pointer based
+  // Container types where the compiler cannot analyze the safety of return
+  // expressions based on pointer arithmetic and unsafe addressors.
+  // Example:
+  // public struct Container<Element: ~Copyable>: ~Copyable {
+  //   var _storage: UnsafeMutableBufferPointer<Element>
+  //   var _count: Int
+  //
+  //   public subscript(index: Int) -> Element {
+  //     @_unsafeSelfDependentResult
+  //     borrow {
+  //       precondition(index >= 0 && index < _count, "Index out of bounds")
+  //       return _storage.baseAddress.unsafelyUnwrapped.advanced(by:
+  //       index).pointee
+  //     }
+  //   }
+  // }
+  if (afd->getAttrs().hasAttribute<UnsafeSelfDependentResultAttr>()) {
+    auto regularLoc = RegularLocation::getAutoGeneratedLocation();
+    auto resultMV = emitRawProjectedLValue(regularLoc, std::move(lvalue));
+    SILValue result = resultMV.getValue();
+    if (resultMV.getType().isAddress() &&
+        F.getConventions().hasGuaranteedResult()) {
+      result = emitLoadBorrowFromGuaranteedAddress(resultMV);
+    }
+    directResults.push_back(result);
+    return false;
+  }
+
+  // If the return expression is not a transitive projection of self,
+  // diagnose.
+  auto *baseExpr = lookThroughProjections(storageRefResult.getStorageRef());
+  if (!baseExpr->isSelfExprOf(afd)) {
+    diagnose(getASTContext(), ret->getStartLoc(),
+             diag::invalid_borrow_accessor_return);
+    diagnose(getASTContext(), ret->getStartLoc(),
+             diag::borrow_accessor_not_a_projection_note);
+    return true;
+  }
+
+  auto resultMV =
+      tryEmitProjectedLValue(ret, std::move(lvalue), TSanKind::None);
+  if (!resultMV) {
+    diagnose(getASTContext(), ret->getStartLoc(),
+             diag::invalid_borrow_accessor_return);
+    diagnose(getASTContext(), ret->getStartLoc(),
+             diag::borrow_accessor_not_a_projection_note);
+    return true;
+  }
+  // For now diagnose multiple return statements in borrow/mutate accessors.
+  // We need additional support for this.
+  // 1. Address phis are banned in SIL.
+  // 2. borrowed from is not inserted in SILGenCleanup.
+  if (!ReturnDest.getBlock()->getPredecessorBlocks().empty()) {
+    diagnose(getASTContext(), ret->getStartLoc(),
+             diag::invalid_multiple_return_borrow_accessor);
+    return true;
+  }
+
+  SILValue result = resultMV->getValue();
+  SILType selfType = F.getSelfArgument()->getType();
+ 
+  if (F.getConventions().hasGuaranteedResult()) {
+    // If we are returning the result of borrow accessor, strip the
+    // unnecessary copy_value + mark_unresolved_non_copyable_value
+    // instructions.
+    if (selfType.isMoveOnly()) {
+    result = lookThroughMoveOnlyCheckerPattern(result);
+    }
+    // If the SIL convention is @guaranteed and the generated result is an
+    // address, emit a load_borrow.
+    if (result->getType().isAddress()) {
+      result = emitLoadBorrowFromGuaranteedAddress(*resultMV);
+    }
+  }
+
+  directResults.push_back(result);
+  return false;
+}
+
 void SILGenFunction::emitReturnExpr(SILLocation branchLoc,
                                     Expr *ret) {
   SmallVector<SILValue, 4> directResults;
@@ -726,9 +894,17 @@ void SILGenFunction::emitReturnExpr(SILLocation branchLoc,
     for (auto cleanup : resultCleanups) {
       Cleanups.forwardCleanup(cleanup);
     }
+  } else if (F.getConventions().hasGuaranteedResult() ||
+             F.getConventions().hasGuaranteedAddressResult()) {
+    bool hasError = emitGuaranteedReturn(branchLoc, ret, directResults);
+    if (hasError) {
+      return;
+    }
+    assert(!directResults.empty());
   } else {
     // SILValue return.
     FullExpr scope(Cleanups, CleanupLocation(ret));
+    FormalEvaluationScope writeback(*this);
     
     // Does the return context require reabstraction?
     RValue RV;
@@ -774,7 +950,11 @@ void StmtEmitter::visitThrowStmt(ThrowStmt *S) {
     return;
   }
 
-  ManagedValue exn = SGF.emitRValueAsSingleValue(S->getSubExpr());
+  ManagedValue exn;
+  {
+    FormalEvaluationScope scope(SGF);
+    exn = SGF.emitRValueAsSingleValue(S->getSubExpr());
+  }
   SGF.emitThrow(S, exn, /* emit a call to willThrow */ true);
 }
 
@@ -1492,23 +1672,29 @@ void StmtEmitter::visitFailStmt(FailStmt *S) {
 
 /// Return a basic block suitable to be the destination block of a
 /// try_apply instruction.  The block is implicitly emitted and filled in.
+///
+/// \param errorAddrOrType Either the address of the indirect error result where
+/// the result will be stored, or the type of the expected Owned error value.
+///
+/// \param suppressErrorPath Should the error path be emitted as unreachable?
 SILBasicBlock *
 SILGenFunction::getTryApplyErrorDest(SILLocation loc,
                                      CanSILFunctionType fnTy,
                                      ExecutorBreadcrumb prevExecutor,
-                                     SILResultInfo errorResult,
-                                     SILValue indirectErrorAddr,
+                                     TaggedUnion<SILValue, SILType> errorAddrOrType,
                                      bool suppressErrorPath) {
   // For now, don't try to re-use destination blocks for multiple
   // failure sites.
   SILBasicBlock *destBB = createBasicBlock(FunctionSection::Postmatter);
 
   SILValue errorValue;
-  if (errorResult.getConvention() == ResultConvention::Owned) {
-    errorValue = destBB->createPhiArgument(getSILType(errorResult, fnTy),
-                                           OwnershipKind::Owned);
+  if (auto ownedErrorTy = errorAddrOrType.dyn_cast<SILType>()) {
+    errorValue = destBB->createPhiArgument(*ownedErrorTy,
+                                               OwnershipKind::Owned);
   } else {
-    errorValue = indirectErrorAddr;
+    auto errorAddr = errorAddrOrType.get<SILValue>();
+    assert(errorAddr->getType().isAddress());
+    errorValue = errorAddr;
   }
 
   assert(B.hasValidInsertionPoint() && B.insertingAtEndOfBlock());
@@ -1581,9 +1767,6 @@ void SILGenFunction::emitThrow(SILLocation loc, ManagedValue exnMV,
       } else {
         // Call the _willThrowTyped entrypoint, which handles
         // arbitrary error types.
-        SILValue tmpBuffer;
-        SILValue error;
-
         FuncDecl *entrypoint = ctx.getWillThrowTyped();
         auto genericSig = entrypoint->getGenericSignature();
         SubstitutionMap subMap = SubstitutionMap::get(
@@ -1596,18 +1779,15 @@ void SILGenFunction::emitThrow(SILLocation loc, ManagedValue exnMV,
           // Materialize the error so we can pass the address down to the
           // swift_willThrowTyped.
           exnMV = exnMV.materialize(*this, loc);
-          error = exnMV.getValue();
-          exn = exnMV.forward(*this);
-        } else {
-          // Claim the exception value.
-          exn = exnMV.forward(*this);
-          error = exn;
         }
 
         emitApplyOfLibraryIntrinsic(
             loc, entrypoint, subMap,
-            { ManagedValue::forForwardedRValue(*this, error) },
+            { exnMV },
             SGFContext());
+
+        // Claim the exception value.
+        exn = exnMV.forward(*this);
       }
     } else {
       // Claim the exception value.
@@ -1677,8 +1857,8 @@ void SILGenFunction::emitThrow(SILLocation loc, ManagedValue exnMV,
       B.createDestroyAddr(loc, exn);
   }
 
-  // Branch to the cleanup destination.
-  Cleanups.emitCleanupsForBranch(ThrowDest, loc, args, IsForUnwind);
+  // Emit clean-ups needed prior to entering throw block.
+  Cleanups.emitCleanupsBeforeBranch(ThrowDest, IsForUnwind);
   
   if (indirectErrorAddr && !exn->getType().isAddress()) {
     // Forward the error value into the return slot now. This has to happen
diff --git a/lib/SILGen/SILGenTopLevel.cpp b/lib/SILGen/SILGenTopLevel.cpp
index 10526ec8b8fc0..715e80a64cd34 100644
--- a/lib/SILGen/SILGenTopLevel.cpp
+++ b/lib/SILGen/SILGenTopLevel.cpp
@@ -65,26 +65,31 @@ void SILGenModule::emitEntryPoint(SourceFile *SF, SILFunction *TopLevel) {
 
   auto prologueLoc = RegularLocation::getModuleLocation();
   prologueLoc.markAsPrologue();
-  if (SF->isAsyncContext()) {
-    // emitAsyncMainThreadStart will create argc and argv.
-    // Just set the main actor as the expected executor; we should
-    // already be running on it.
-    SILValue executor = TopLevelSGF.emitMainExecutor(prologueLoc);
-    TopLevelSGF.ExpectedExecutor.set(TopLevelSGF.B.createOptionalSome(
-        prologueLoc, executor, SILType::getOptionalType(executor->getType())));
-  } else {
-    // Create the argc and argv arguments.
-    auto entry = TopLevelSGF.B.getInsertionBB();
-    auto context = TopLevelSGF.getTypeExpansionContext();
-    auto paramTypeIter =
-        TopLevelSGF.F.getConventions().getParameterSILTypes(context).begin();
-
-    entry->createFunctionArgument(*paramTypeIter);
-    entry->createFunctionArgument(*std::next(paramTypeIter));
-  }
 
   {
     Scope S(TopLevelSGF.Cleanups, moduleCleanupLoc);
+
+    if (SF->isAsyncContext()) {
+      // emitAsyncMainThreadStart will create argc and argv.
+      // Just set the main actor as the expected executor; we should
+      // already be running on it.
+      auto mainActorType =
+          getASTContext().getMainActorType()->getCanonicalType();
+      TopLevelSGF.ExpectedExecutor.set(
+          TopLevelSGF.emitGlobalActorIsolation(prologueLoc, mainActorType)
+              .borrow(TopLevelSGF, prologueLoc)
+              .getValue());
+    } else {
+      // Create the argc and argv arguments.
+      auto entry = TopLevelSGF.B.getInsertionBB();
+      auto context = TopLevelSGF.getTypeExpansionContext();
+      auto paramTypeIter =
+          TopLevelSGF.F.getConventions().getParameterSILTypes(context).begin();
+
+      entry->createFunctionArgument(*paramTypeIter);
+      entry->createFunctionArgument(*std::next(paramTypeIter));
+    }
+
     SILGenTopLevel(TopLevelSGF).visitSourceFile(SF);
   }
 
@@ -453,7 +458,7 @@ void SILGenTopLevel::visitTopLevelCodeDecl(TopLevelCodeDecl *TD) {
     } else if (auto *E = ESD.dyn_cast<Expr *>()) {
       SGF.emitIgnoredExpr(E);
     } else {
-      SGF.visit(ESD.get<Decl *>());
+      SGF.visit(cast<Decl *>(ESD));
     }
   }
 }
diff --git a/lib/SILGen/SILGenType.cpp b/lib/SILGen/SILGenType.cpp
index 0264abdf7eb4e..d81293b243779 100644
--- a/lib/SILGen/SILGenType.cpp
+++ b/lib/SILGen/SILGenType.cpp
@@ -38,6 +38,7 @@
 #include "swift/SIL/SILVTableVisitor.h"
 #include "swift/SIL/SILWitnessVisitor.h"
 #include "swift/SIL/TypeLowering.h"
+#include "clang/AST/Decl.h"
 
 using namespace swift;
 using namespace Lowering;
@@ -454,8 +455,11 @@ template<typename T> class SILGenWitnessTable : public SILWitnessVisitor<T> {
         //   () -> NSString
         // But the first is correct, so make sure we don't mark this witness
         // as foreign.
-        if (dyn_cast_or_null<clang::CXXMethodDecl>(
-                witness.getDecl()->getClangDecl()))
+        const auto *clangDecl = witness.getDecl()->getClangDecl();
+        if (clangDecl &&
+            (dyn_cast<clang::CXXMethodDecl>(clangDecl) ||
+             (isa<clang::FunctionDecl>(clangDecl) &&
+              cast<clang::FunctionDecl>(clangDecl)->isOverloadedOperator())))
           newDecl = newDecl.asForeign();
         return addMethodImplementation(
             requirementRef, getWitnessRef(newDecl, witness), witness);
@@ -540,7 +544,7 @@ class SILGenConformance : public SILGenWitnessTable<SILGenConformance> {
   SILGenModule &SGM;
   NormalProtocolConformance *Conformance;
   std::vector<SILWitnessTable::Entry> Entries;
-  std::vector<SILWitnessTable::ConditionalConformance> ConditionalConformances;
+  std::vector<ProtocolConformanceRef> ConditionalConformances;
   SILLinkage Linkage;
   SerializedKind_t SerializedKind;
 
@@ -602,7 +606,7 @@ class SILGenConformance : public SILGenWitnessTable<SILGenConformance> {
 
     // Otherwise if we have no witness table yet, create it.
     return SILWitnessTable::create(SGM.M, Linkage, SerializedKind, Conformance,
-                                   Entries, ConditionalConformances);
+                                   Entries, ConditionalConformances, /*specialized=*/false);
   }
 
   void addProtocolConformanceDescriptor() {
@@ -678,13 +682,12 @@ class SILGenConformance : public SILGenWitnessTable<SILGenConformance> {
                     SILWitnessTable::MethodWitness{requirementRef, witnessFn});
   }
 
-  void addAssociatedType(AssociatedType requirement) {
+  void addAssociatedType(AssociatedTypeDecl *assocType) {
     // Find the substitution info for the witness type.
-    auto td = requirement.getAssociation();
-    Type witness = Conformance->getTypeWitness(td);
+    Type witness = Conformance->getTypeWitness(assocType);
 
     // Emit the record for the type itself.
-    Entries.push_back(SILWitnessTable::AssociatedTypeWitness{td,
+    Entries.push_back(SILWitnessTable::AssociatedTypeWitness{assocType,
                                                 witness->getCanonicalType()});
   }
 
@@ -692,13 +695,9 @@ class SILGenConformance : public SILGenWitnessTable<SILGenConformance> {
     auto assocConformance =
       Conformance->getAssociatedConformance(req.getAssociation(),
                                             req.getAssociatedRequirement());
-    auto substType =
-      Conformance->getAssociatedType(req.getAssociation())->getCanonicalType();
-
     SGM.useConformance(assocConformance);
-
     Entries.push_back(SILWitnessTable::AssociatedConformanceWitness{
-        req.getAssociation(), substType, assocConformance});
+        req.getAssociation(), assocConformance});
   }
 
   void addConditionalRequirements() {
@@ -709,8 +708,7 @@ class SILGenConformance : public SILGenWitnessTable<SILGenConformance> {
           assert(conformance &&
                  "unable to find conformance that should be known");
 
-          ConditionalConformances.push_back(
-              SILWitnessTable::ConditionalConformance{type, conformance});
+          ConditionalConformances.push_back(conformance);
 
           return /*finished?*/ false;
         });
@@ -733,7 +731,7 @@ SILGenModule::getWitnessTable(NormalProtocolConformance *conformance) {
 }
 
 SILFunction *SILGenModule::emitProtocolWitness(
-    ProtocolConformanceRef conformance, SILLinkage linkage,
+    ProtocolConformanceRef origConformance, SILLinkage linkage,
     SerializedKind_t serializedKind, SILDeclRef requirement,
     SILDeclRef witnessRef, IsFreeFunctionWitness_t isFree, Witness witness) {
   auto requirementInfo =
@@ -773,7 +771,8 @@ SILFunction *SILGenModule::emitProtocolWitness(
   // The type of the witness thunk.
   auto reqtSubstTy = cast<AnyFunctionType>(
     reqtOrigTy->substGenericArgs(reqtSubMap)
-      ->getReducedType(genericSig));
+              ->mapTypeOutOfContext()
+              ->getCanonicalType());
 
   // Rewrite the conformance in terms of the requirement environment's Self
   // type, which might have a different generic signature than the type
@@ -783,14 +782,19 @@ SILFunction *SILGenModule::emitProtocolWitness(
   // in a protocol extension, the generic signature will have an additional
   // generic parameter representing Self, so the generic parameters of the
   // class will all be shifted down by one.
-  if (reqtSubMap) {
-    auto requirement = conformance.getProtocol();
-    auto self = requirement->getSelfInterfaceType()->getCanonicalType();
-
-    conformance = reqtSubMap.lookupConformance(self, requirement);
+  auto conformance = origConformance;
+  ProtocolConformance *manglingConformance = nullptr;
+  if (conformance.isConcrete()) {
+    conformance = reqtSubMap.lookupConformance(M.getASTContext().TheSelfType,
+                                               origConformance.getProtocol())
+        .mapConformanceOutOfContext();
+    ASSERT(!conformance.isAbstract());
 
-    if (genericEnv)
-      reqtSubMap = reqtSubMap.subst(genericEnv->getForwardingSubstitutionMap());
+    manglingConformance = conformance.getConcrete();
+    if (auto *inherited = dyn_cast<InheritedProtocolConformance>(manglingConformance)) {
+      manglingConformance = inherited->getInheritedConformance();
+      conformance = ProtocolConformanceRef(manglingConformance);
+    }
   }
 
   // Generic signatures where all parameters are concrete are lowered away
@@ -812,20 +816,14 @@ SILFunction *SILGenModule::emitProtocolWitness(
   // But this is expensive, so we only do it for coroutine lowering.
   // When they're part of the AST function type, we can remove this
   // parameter completely.
+  bool allowDuplicateThunk = false;
   std::optional<SubstitutionMap> witnessSubsForTypeLowering;
   if (auto accessor = dyn_cast<AccessorDecl>(requirement.getDecl())) {
     if (accessor->isCoroutine()) {
       witnessSubsForTypeLowering =
         witness.getSubstitutions().mapReplacementTypesOutOfContext();
-    }
-  }
-
-  ProtocolConformance *manglingConformance = nullptr;
-  if (conformance.isConcrete()) {
-    manglingConformance = conformance.getConcrete();
-    if (auto *inherited = dyn_cast<InheritedProtocolConformance>(manglingConformance)) {
-      manglingConformance = inherited->getInheritedConformance();
-      conformance = ProtocolConformanceRef(manglingConformance);
+      if (accessor->isRequirementWithSynthesizedDefaultImplementation())
+        allowDuplicateThunk = true;
     }
   }
 
@@ -865,12 +863,18 @@ SILFunction *SILGenModule::emitProtocolWitness(
   // setting on the theory that forcing inlining off should only
   // effect the user's function, not otherwise invisible thunks.
   Inline_t InlineStrategy = InlineDefault;
-  if (witnessRef.isAlwaysInline())
-    InlineStrategy = AlwaysInline;
+  if (witnessRef.isUnderscoredAlwaysInline())
+    InlineStrategy = HeuristicAlwaysInline;
+  // We don't guarantee @inline(always) will inline devirtualized thunks. But we
+  // want to make an best-effort attempt to inline.
+  else if (witnessRef.isAlwaysInline())
+    InlineStrategy = HeuristicAlwaysInline;
+
 
   SILFunction *f = M.lookUpFunction(nameBuffer);
-  if (f)
+  if (allowDuplicateThunk && f)
     return f;
+  ASSERT(!f);
 
   SILGenFunctionBuilder builder(*this);
   f = builder.createFunction(
@@ -897,7 +901,8 @@ SILFunction *SILGenModule::emitProtocolWitness(
   bool isPreconcurrency = false;
   if (conformance.isConcrete()) {
     if (auto *C =
-            dyn_cast<NormalProtocolConformance>(conformance.getConcrete()))
+          dyn_cast<NormalProtocolConformance>(
+            conformance.getConcrete()->getRootConformance()))
       isPreconcurrency = C->isPreconcurrency();
   }
 
@@ -909,6 +914,12 @@ SILFunction *SILGenModule::emitProtocolWitness(
                           witness.getEnterIsolation());
 
   emitLazyConformancesForFunction(f);
+
+  if (auto isolation = getSILFunctionTypeActorIsolation(
+          reqtSubstTy, requirement, witnessRef)) {
+    f->setActorIsolation(*isolation);
+  }
+
   return f;
 }
 
@@ -1014,7 +1025,7 @@ class SILGenSelfConformanceWitnessTable
 
     // Create the witness table.
     (void) SILWitnessTable::create(SGM.M, linkage, serialized, conformance,
-                                   entries, /*conditional*/ {});
+                                   entries, /*conditional*/ {}, /*specialized=*/false);
   }
 
   void addProtocolConformanceDescriptor() {}
@@ -1028,7 +1039,7 @@ class SILGenSelfConformanceWitnessTable
   void addAssociatedConformance(AssociatedConformance conformance) {
     llvm_unreachable("associated conformances not supported in self-conformance");
   }
-  void addAssociatedType(AssociatedType type) {
+  void addAssociatedType(AssociatedTypeDecl *assocType) {
     llvm_unreachable("associated types not supported in self-conformance");
   }
   void addPlaceholder(MissingMemberDecl *placeholder) {
@@ -1106,14 +1117,14 @@ class SILGenDefaultWitnessTable
     DefaultWitnesses.push_back(entry);
   }
 
-  void addAssociatedType(AssociatedType req) {
-    Type witness = Proto->getDefaultTypeWitness(req.getAssociation());
+  void addAssociatedType(AssociatedTypeDecl *assocType) {
+    Type witness = Proto->getDefaultTypeWitness(assocType);
     if (!witness)
       return addMissingDefault();
 
     Type witnessInContext = Proto->mapTypeIntoContext(witness);
     auto entry = SILWitnessTable::AssociatedTypeWitness{
-                                          req.getAssociation(),
+                                          assocType,
                                           witnessInContext->getCanonicalType()};
     DefaultWitnesses.push_back(entry);
   }
@@ -1127,7 +1138,7 @@ class SILGenDefaultWitnessTable
       return addMissingDefault();
 
     auto entry = SILWitnessTable::AssociatedConformanceWitness{
-        req.getAssociation(), req.getAssociation(), witness};
+        req.getAssociation(), witness};
     DefaultWitnesses.push_back(entry);
   }
 };
@@ -1165,6 +1176,8 @@ originalAccessorKindForReplacementKind(AccessorKind kind) {
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
   case AccessorKind::Init:
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
     return std::nullopt;
   }
 }
@@ -1298,8 +1311,9 @@ SILFunction *SILGenModule::emitDefaultOverride(SILDeclRef replacement,
   SmallVector<ManagedValue, 4> params;
   SmallVector<ManagedValue, 4> indirectResults;
   SmallVector<ManagedValue, 4> indirectErrors;
+  ManagedValue implicitIsolationParam;
   SGF.collectThunkParams(replacement.getDecl(), params, &indirectResults,
-                         &indirectErrors);
+                         &indirectErrors, &implicitIsolationParam);
 
   auto self = params.back();
 
@@ -1315,6 +1329,11 @@ SILFunction *SILGenModule::emitDefaultOverride(SILDeclRef replacement,
   for (auto result : indirectResults) {
     args.push_back(result.forward(SGF));
   }
+  // Indirect errors would go here, but we don't currently support
+  // throwing coroutines.
+  if (implicitIsolationParam.isValid()) {
+    args.push_back(implicitIsolationParam.forward(SGF));
+  }
   for (auto param : params) {
     args.push_back(param.forward(SGF));
   }
@@ -1525,6 +1544,8 @@ class SILGenType : public TypeMemberVisitor<SILGenType> {
     auto initInfo = vd->getPropertyWrapperInitializerInfo();
     if (initInfo.hasInitFromWrappedValue() && !vd->isStatic()) {
       SGM.emitPropertyWrapperBackingInitializer(vd);
+      // Output this unconditionally, SIL optimizer will remove it if not needed
+      SGM.emitPropertyWrappedFieldInitAccessor(vd);
     }
 
     visitAbstractStorageDecl(vd);
@@ -1565,6 +1586,13 @@ void SILGenModule::visitNominalTypeDecl(NominalTypeDecl *ntd) {
   SILGenType(*this, ntd).emitType();
 }
 
+void SILGenModule::visitImportedNontrivialNoncopyableType(
+  NominalTypeDecl *nominal) {
+  emitNonCopyableTypeDeinitTable(nominal);
+  SILGenType(*this, nominal)
+      .visitDestructorDecl(nominal->getValueTypeDestructor());
+}
+
 /// SILGenExtension - an ASTVisitor for generating SIL from method declarations
 /// and protocol conformances inside type extensions.
 class SILGenExtension : public TypeMemberVisitor<SILGenExtension> {
diff --git a/lib/SILGen/StorageRefResult.h b/lib/SILGen/StorageRefResult.h
new file mode 100644
index 0000000000000..10fe7c4b4563c
--- /dev/null
+++ b/lib/SILGen/StorageRefResult.h
@@ -0,0 +1,106 @@
+#ifndef SWIFT_SILGEN_STORAGEREFRESULT_H
+#define SWIFT_SILGEN_STORAGEREFRESULT_H
+
+#include "swift/AST/Expr.h"
+
+namespace swift {
+/// Container to hold the result of a search for the storage reference
+/// when determining to emit a borrow.
+struct StorageRefResult {
+private:
+  Expr *storageRef;
+  Expr *transitiveRoot;
+
+public:
+  // Represents an empty result
+  StorageRefResult() : storageRef(nullptr), transitiveRoot(nullptr) {}
+  bool isEmpty() const { return transitiveRoot == nullptr; }
+  operator bool() const { return !isEmpty(); }
+
+  /// The root of the expression that accesses the storage in \c storageRef.
+  /// When in doubt, this is probably what you want, as it includes the
+  /// entire expression tree involving the reference.
+  Expr *getTransitiveRoot() const { return transitiveRoot; }
+
+  /// The direct storage reference that was discovered.
+  Expr *getStorageRef() const { return storageRef; }
+
+  StorageRefResult(Expr *storageRef, Expr *transitiveRoot)
+      : storageRef(storageRef), transitiveRoot(transitiveRoot) {
+    assert(storageRef && transitiveRoot && "use the zero-arg init for empty");
+  }
+
+  // Initializes a storage reference where the base matches the ref.
+  StorageRefResult(Expr *storageRef)
+      : StorageRefResult(storageRef, storageRef) {}
+
+  StorageRefResult withTransitiveRoot(StorageRefResult refResult) const {
+    return withTransitiveRoot(refResult.transitiveRoot);
+  }
+
+  StorageRefResult withTransitiveRoot(Expr *newRoot) const {
+    return StorageRefResult(storageRef, newRoot);
+  }
+
+  static StorageRefResult findStorageReferenceExprForBorrow(Expr *e) {
+    e = e->getSemanticsProvidingExpr();
+
+    // These are basically defined as the cases implemented by SILGenLValue.
+
+    // Direct storage references.
+    if (auto dre = dyn_cast<DeclRefExpr>(e)) {
+      if (isa<VarDecl>(dre->getDecl()))
+        return dre;
+    } else if (auto mre = dyn_cast<MemberRefExpr>(e)) {
+      if (isa<VarDecl>(mre->getDecl().getDecl()))
+        return mre;
+    } else if (isa<SubscriptExpr>(e)) {
+      return e;
+    } else if (isa<OpaqueValueExpr>(e)) {
+      return e;
+    } else if (isa<KeyPathApplicationExpr>(e)) {
+      return e;
+
+      // Transitive storage references.  Look through these to see if the
+      // sub-expression is a storage reference, but don't return the
+      // sub-expression.
+    } else if (auto tue = dyn_cast<TupleElementExpr>(e)) {
+      if (auto result = findStorageReferenceExprForBorrow(tue->getBase()))
+        return result.withTransitiveRoot(tue);
+
+    } else if (auto fve = dyn_cast<ForceValueExpr>(e)) {
+      if (auto result = findStorageReferenceExprForBorrow(fve->getSubExpr()))
+        return result.withTransitiveRoot(fve);
+
+    } else if (auto boe = dyn_cast<BindOptionalExpr>(e)) {
+      if (auto result = findStorageReferenceExprForBorrow(boe->getSubExpr()))
+        return result.withTransitiveRoot(boe);
+
+    } else if (auto oe = dyn_cast<OpenExistentialExpr>(e)) {
+      if (findStorageReferenceExprForBorrow(oe->getExistentialValue()))
+        if (auto result = findStorageReferenceExprForBorrow(oe->getSubExpr()))
+          return result.withTransitiveRoot(oe);
+
+    } else if (auto bie = dyn_cast<DotSyntaxBaseIgnoredExpr>(e)) {
+      if (auto result = findStorageReferenceExprForBorrow(bie->getRHS()))
+        return result.withTransitiveRoot(bie);
+
+    } else if (auto te = dyn_cast<AnyTryExpr>(e)) {
+      if (auto result = findStorageReferenceExprForBorrow(te->getSubExpr()))
+        return result.withTransitiveRoot(te);
+
+    } else if (auto ioe = dyn_cast<InOutExpr>(e)) {
+      if (auto result = findStorageReferenceExprForBorrow(ioe->getSubExpr()))
+        return result.withTransitiveRoot(ioe);
+    } else if (auto le = dyn_cast<LoadExpr>(e)) {
+      if (auto result = findStorageReferenceExprForBorrow(le->getSubExpr()))
+        return result.withTransitiveRoot(le);
+    }
+
+    return StorageRefResult();
+  }
+};
+
+} // namespace swift
+
+#endif
\ No newline at end of file
diff --git a/lib/SILOptimizer/Analysis/ARCAnalysis.cpp b/lib/SILOptimizer/Analysis/ARCAnalysis.cpp
index 4740b4b3090f4..702029bac29d3 100644
--- a/lib/SILOptimizer/Analysis/ARCAnalysis.cpp
+++ b/lib/SILOptimizer/Analysis/ARCAnalysis.cpp
@@ -104,7 +104,7 @@ static bool canApplyOfBuiltinUseNonTrivialValues(BuiltinInst *BInst) {
 
   auto &II = BInst->getIntrinsicInfo();
   if (II.ID != llvm::Intrinsic::not_intrinsic) {
-    auto attrs = II.getOrCreateAttributes(F->getASTContext());
+    auto &attrs = II.getOrCreateFnAttributes(F->getASTContext());
     if (attrs.getMemoryEffects().doesNotAccessMemory()) {
       for (auto &Op : BInst->getAllOperands()) {
         if (!Op.get()->getType().isTrivial(*F)) {
diff --git a/lib/SILOptimizer/Analysis/ColdBlockInfo.cpp b/lib/SILOptimizer/Analysis/ColdBlockInfo.cpp
index f42fe7b60d449..9fde5f1ea0431 100644
--- a/lib/SILOptimizer/Analysis/ColdBlockInfo.cpp
+++ b/lib/SILOptimizer/Analysis/ColdBlockInfo.cpp
@@ -441,7 +441,7 @@ bool ColdBlockInfo::isCold(const SILBasicBlock *BB) const {
 }
 
 void ColdBlockInfo::resetToCold(const SILBasicBlock *BB) {
-  auto &entry = EnergyMap.getOrInsertDefault(BB);
+  auto &entry = EnergyMap[BB];
   if (isColdEnergy(entry))
     return;
 
@@ -451,7 +451,7 @@ void ColdBlockInfo::resetToCold(const SILBasicBlock *BB) {
 }
 
 void ColdBlockInfo::set(const SILBasicBlock *BB, State::Temperature temp) {
-  auto &entry = EnergyMap.getOrInsertDefault(BB);
+  auto &entry = EnergyMap[BB];
   if (entry.contains(temp))
     return;
 
diff --git a/lib/SILOptimizer/Analysis/LoopRegionAnalysis.cpp b/lib/SILOptimizer/Analysis/LoopRegionAnalysis.cpp
index d6c7b26d5bf6d..3c899dae55088 100644
--- a/lib/SILOptimizer/Analysis/LoopRegionAnalysis.cpp
+++ b/lib/SILOptimizer/Analysis/LoopRegionAnalysis.cpp
@@ -35,15 +35,13 @@ LoopRegion::~LoopRegion() {
 }
 
 LoopRegion::BlockTy *LoopRegion::getBlock() const {
-  return Ptr.get<BlockTy *>();
+  return cast<BlockTy *>(Ptr);
 }
 
-LoopRegion::LoopTy *LoopRegion::getLoop() const {
-  return Ptr.get<LoopTy *>();
-}
+LoopRegion::LoopTy *LoopRegion::getLoop() const { return cast<LoopTy *>(Ptr); }
 
 LoopRegion::FunctionTy *LoopRegion::getFunction() const {
-  return Ptr.get<FunctionTy *>();
+  return cast<FunctionTy *>(Ptr);
 }
 
 void LoopRegion::dump(bool isVerbose) const {
diff --git a/lib/SILOptimizer/Analysis/RegionAnalysis.cpp b/lib/SILOptimizer/Analysis/RegionAnalysis.cpp
index 9881890ac65c9..c257a4b1d793f 100644
--- a/lib/SILOptimizer/Analysis/RegionAnalysis.cpp
+++ b/lib/SILOptimizer/Analysis/RegionAnalysis.cpp
@@ -93,21 +93,40 @@ regionanalysisimpl::getApplyIsolationCrossing(SILInstruction *inst) {
 
 namespace {
 
-struct UseDefChainVisitor
-    : public AccessUseDefChainVisitor<UseDefChainVisitor, SILValue> {
-  bool isMerge = false;
+/// A visitor that walks from uses -> def attempting to determine an object or
+/// address base for the passed in address.
+///
+/// It also is used to determine if we are assigning into a part of an aggregate
+/// or are assigning over an entire value.
+///
+/// RULES:
+///
+/// 1. We allow for sendable types to be rooted in non-Sendable types. We allow
+/// for our caller to reason about this by placing in our metadata if the entire
+/// search path was just sendable types. If any are non-Sendable except for our
+/// base, we need to be more conservative.
+///
+/// 2. We stop when we find a non-Sendable type rooted in a Sendable type. In
+/// such a case, we want to process the non-Sendable type as if it is rooted in
+/// the Sendable type.
+struct AddressBaseComputingVisitor
+    : public AccessUseDefChainVisitor<AddressBaseComputingVisitor, SILValue> {
+  bool isProjectedFromAggregate = false;
 
-  /// The actor isolation that we found while walking from use->def. Always set
-  /// to the first one encountered.
-  std::optional<ActorIsolation> actorIsolation;
+  SILValue value;
 
   SILValue visitAll(SILValue sourceAddr) {
+    // If our initial value is Sendable, then it is our "value".
+    if (SILIsolationInfo::isSendableType(sourceAddr))
+      value = sourceAddr;
+
     SILValue result = visit(sourceAddr);
     if (!result)
       return sourceAddr;
 
-    while (SILValue nextAddr = visit(result))
+    while (SILValue nextAddr = visit(result)) {
       result = nextAddr;
+    }
 
     return result;
   }
@@ -122,7 +141,16 @@ struct UseDefChainVisitor
     return SILValue();
   }
 
-  SILValue visitNonAccess(SILValue) { return SILValue(); }
+  SILValue visitNonAccess(SILValue value) {
+    // For now since it is late in 6.2, work around vector base addr not being
+    // treated as a projection.
+    if (auto *v = dyn_cast<VectorBaseAddrInst>(value)) {
+      isProjectedFromAggregate = true;
+      return v->getOperand();
+    }
+
+    return SILValue();
+  }
 
   SILValue visitPhi(SILPhiArgument *phi) {
     llvm_unreachable("Should never hit this");
@@ -153,23 +181,24 @@ struct UseDefChainVisitor
         return SILValue();
     }
 
-    // If we do not have an identity cast, mark this as a merge.
-    isMerge |= castType != AccessStorageCast::Identity;
+    // If we do not have an identity cast, mark this as if we are projecting out
+    // of an aggregate that will require us to merge.
+    isProjectedFromAggregate |= castType != AccessStorageCast::Identity;
 
     return sourceAddr->get();
   }
 
-  SILValue visitAccessProjection(SingleValueInstruction *inst,
+  SILValue visitAccessProjection(SingleValueInstruction *projInst,
                                  Operand *sourceAddr) {
     // See if this access projection is into a single element value. If so, we
     // do not want to treat this as a merge.
-    if (auto p = Projection(inst)) {
+    if (auto p = Projection(projInst)) {
       switch (p.getKind()) {
       // Currently if we load and then project_box from a memory location,
       // we treat that as a projection. This follows the semantics/notes in
       // getAccessProjectionOperand.
       case ProjectionKind::Box:
-        return cast<ProjectBoxInst>(inst)->getOperand();
+        return cast<ProjectBoxInst>(projInst)->getOperand();
       case ProjectionKind::Upcast:
       case ProjectionKind::RefCast:
       case ProjectionKind::BlockStorageCast:
@@ -179,44 +208,58 @@ struct UseDefChainVisitor
         llvm_unreachable("Shouldn't see this here");
       case ProjectionKind::Index:
         // Index is always a merge.
-        isMerge = true;
+        isProjectedFromAggregate = true;
         break;
       case ProjectionKind::Enum: {
-        auto op = cast<UncheckedTakeEnumDataAddrInst>(inst)->getOperand();
+        auto op = cast<UncheckedTakeEnumDataAddrInst>(projInst)->getOperand();
+
+        bool isOperandSendable = !SILIsolationInfo::isNonSendableType(
+            op->getType(), op->getFunction());
 
-        // See if our operand type is a sendable type. In such a case, we do not
-        // want to look through our operand.
-        if (!SILIsolationInfo::isNonSendableType(op->getType(),
-                                                 op->getFunction()))
-          return SILValue();
+        // If our operand is Sendable and our field is non-Sendable and we have
+        // not stashed a value yet, stash value.
+        if (!value && isOperandSendable &&
+            SILIsolationInfo::isNonSendableType(projInst->getType(),
+                                                projInst->getFunction())) {
+          value = projInst;
+        }
 
         break;
       }
       case ProjectionKind::Tuple: {
         // These are merges if we have multiple fields.
-        auto op = cast<TupleElementAddrInst>(inst)->getOperand();
+        auto op = cast<TupleElementAddrInst>(projInst)->getOperand();
+
+        bool isOperandSendable = !SILIsolationInfo::isNonSendableType(
+            op->getType(), op->getFunction());
 
-        if (!SILIsolationInfo::isNonSendableType(op->getType(),
-                                                 op->getFunction()))
-          return SILValue();
+        // If our operand is Sendable and our field is non-Sendable, we need to
+        // bail since we want to root the non-Sendable type in the Sendable
+        // type.
+        if (!value && isOperandSendable &&
+            SILIsolationInfo::isNonSendableType(projInst->getType(),
+                                                projInst->getFunction()))
+          value = projInst;
 
-        isMerge |= op->getType().getNumTupleElements() > 1;
+        isProjectedFromAggregate |= op->getType().getNumTupleElements() > 1;
         break;
       }
       case ProjectionKind::Struct:
-        auto op = cast<StructElementAddrInst>(inst)->getOperand();
+        auto op = cast<StructElementAddrInst>(projInst)->getOperand();
 
-        // See if our result type is a sendable type. In such a case, we do not
-        // want to look through the struct_element_addr since we do not want to
-        // identify the sendable type with the non-sendable operand. These we
-        // are always going to ignore anyways since a sendable let/var field of
-        // a struct can always be used.
-        if (!SILIsolationInfo::isNonSendableType(op->getType(),
-                                                 op->getFunction()))
-          return SILValue();
+        bool isOperandSendable = !SILIsolationInfo::isNonSendableType(
+            op->getType(), op->getFunction());
+
+        // If our operand is Sendable and our field is non-Sendable, we need to
+        // bail since we want to root the non-Sendable type in the Sendable
+        // type.
+        if (!value && isOperandSendable &&
+            SILIsolationInfo::isNonSendableType(projInst->getType(),
+                                                projInst->getFunction()))
+          value = projInst;
 
         // These are merges if we have multiple fields.
-        isMerge |= op->getType().getNumNominalFields() > 1;
+        isProjectedFromAggregate |= op->getType().getNumNominalFields() > 1;
         break;
       }
     }
@@ -274,7 +317,10 @@ static bool isStaticallyLookThroughInst(SILInstruction *inst) {
   case SILInstructionKind::StrongCopyUnmanagedValueInst:
   case SILInstructionKind::RefToUnmanagedInst:
   case SILInstructionKind::UnmanagedToRefInst:
-  case SILInstructionKind::InitExistentialValueInst:
+  case SILInstructionKind::UncheckedEnumDataInst:
+  case SILInstructionKind::StructElementAddrInst:
+  case SILInstructionKind::TupleElementAddrInst:
+  case SILInstructionKind::VectorBaseAddrInst:
     return true;
   case SILInstructionKind::MoveValueInst:
     // Look through if it isn't from a var decl.
@@ -282,9 +328,17 @@ static bool isStaticallyLookThroughInst(SILInstruction *inst) {
   case SILInstructionKind::BeginBorrowInst:
     // Look through if it isn't from a var decl.
     return !cast<BeginBorrowInst>(inst)->isFromVarDecl();
+  case SILInstructionKind::InitExistentialValueInst:
+    return !SILIsolationInfo::getConformanceIsolation(inst);
   case SILInstructionKind::UnconditionalCheckedCastInst: {
     auto cast = SILDynamicCastInst::getAs(inst);
     assert(cast);
+
+    // If this cast introduces isolation due to conformances, we cannot look
+    // through it to the source.
+    if (SILIsolationInfo::getConformanceIsolation(inst))
+      return false;
+
     if (cast.isRCIdentityPreserving())
       return true;
     return false;
@@ -292,24 +346,6 @@ static bool isStaticallyLookThroughInst(SILInstruction *inst) {
   }
 }
 
-static bool isLookThroughIfResultNonSendable(SILInstruction *inst) {
-  switch (inst->getKind()) {
-  default:
-    return false;
-  case SILInstructionKind::RawPointerToRefInst:
-    return true;
-  }
-}
-
-static bool isLookThroughIfOperandNonSendable(SILInstruction *inst) {
-  switch (inst->getKind()) {
-  default:
-    return false;
-  case SILInstructionKind::RefToRawPointerInst:
-    return true;
-  }
-}
-
 static bool isLookThroughIfOperandAndResultNonSendable(SILInstruction *inst) {
   switch (inst->getKind()) {
   default:
@@ -317,11 +353,10 @@ static bool isLookThroughIfOperandAndResultNonSendable(SILInstruction *inst) {
   case SILInstructionKind::UncheckedTrivialBitCastInst:
   case SILInstructionKind::UncheckedBitwiseCastInst:
   case SILInstructionKind::UncheckedValueCastInst:
-  case SILInstructionKind::StructElementAddrInst:
-  case SILInstructionKind::TupleElementAddrInst:
-  case SILInstructionKind::UncheckedTakeEnumDataAddrInst:
   case SILInstructionKind::ConvertEscapeToNoEscapeInst:
   case SILInstructionKind::ConvertFunctionInst:
+  case SILInstructionKind::RefToRawPointerInst:
+  case SILInstructionKind::RawPointerToRefInst:
     return true;
   }
 }
@@ -395,9 +430,9 @@ struct TermArgSources {
 
 static bool isProjectedFromAggregate(SILValue value) {
   assert(value->getType().isAddress());
-  UseDefChainVisitor visitor;
+  AddressBaseComputingVisitor visitor;
   visitor.visitAll(value);
-  return visitor.isMerge;
+  return visitor.isProjectedFromAggregate;
 }
 
 namespace {
@@ -623,13 +658,8 @@ RegionAnalysisValueMap::initializeTrackableValue(
   return {{iter.first->first, iter.first->second}, true};
 }
 
-/// If \p isAddressCapturedByPartialApply is set to true, then this value is
-/// an address that is captured by a partial_apply and we want to treat it as
-/// may alias.
-TrackableValue RegionAnalysisValueMap::getTrackableValue(
+TrackableValue RegionAnalysisValueMap::getTrackableValueHelper(
     SILValue value, bool isAddressCapturedByPartialApply) const {
-  auto info = getUnderlyingTrackedValue(value);
-  value = info.value;
 
   auto *self = const_cast<RegionAnalysisValueMap *>(this);
   auto iter = self->equivalenceClassValuesToState.try_emplace(
@@ -667,23 +697,6 @@ TrackableValue RegionAnalysisValueMap::getTrackableValue(
 
   // Ok, at this point we have a non-Sendable value. First process addresses.
   if (value->getType().isAddress()) {
-    // If we were able to find this was actor isolated from finding our
-    // underlying object, use that. It is never wrong.
-    if (info.actorIsolation) {
-      SILIsolationInfo isolation;
-      if (info.value->getType().isAnyActor()) {
-        isolation = SILIsolationInfo::getActorInstanceIsolated(
-            value, info.value, info.actorIsolation->getActor());
-      } else if (info.actorIsolation->isGlobalActor()) {
-        isolation = SILIsolationInfo::getGlobalActorIsolated(
-            value, info.actorIsolation->getGlobalActor());
-      }
-
-      if (isolation) {
-        iter.first->getSecond().setIsolationRegionInfo(isolation);
-      }
-    }
-
     auto storage = AccessStorageWithBase::compute(value);
     if (storage.storage) {
       // Check if we have a uniquely identified address that was not captured
@@ -705,19 +718,6 @@ TrackableValue RegionAnalysisValueMap::getTrackableValue(
   if (isa<LoadInst, LoadBorrowInst>(iter.first->first.getValue())) {
     auto *svi = cast<SingleValueInstruction>(iter.first->first.getValue());
 
-    // See if we can use get underlying tracked value to find if it is actor
-    // isolated.
-    //
-    // TODO: Instead of using AccessStorageBase, just use our own visitor
-    // everywhere. Just haven't done it due to possible perturbations.
-    auto parentAddrInfo = getUnderlyingTrackedValue(svi);
-    if (parentAddrInfo.actorIsolation) {
-      iter.first->getSecond().setIsolationRegionInfo(
-          SILIsolationInfo::getActorInstanceIsolated(
-              svi, parentAddrInfo.value,
-              parentAddrInfo.actorIsolation->getActor()));
-    }
-
     auto storage = AccessStorageWithBase::compute(svi->getOperand(0));
     if (storage.storage) {
       if (auto isolation = SILIsolationInfo::get(storage.base)) {
@@ -740,6 +740,25 @@ TrackableValue RegionAnalysisValueMap::getTrackableValue(
   return {iter.first->first, iter.first->second};
 }
 
+/// If \p isAddressCapturedByPartialApply is set to true, then this value is
+/// an address that is captured by a partial_apply and we want to treat it as
+/// may alias.
+TrackableValueLookupResult RegionAnalysisValueMap::getTrackableValue(
+    SILValue inputValue, bool isAddressCapturedByPartialApply) const {
+  auto info = getUnderlyingTrackedValue(inputValue);
+  SILValue value = info.value;
+  SILValue base = info.base;
+
+  auto trackedValue =
+      getTrackableValueHelper(value, isAddressCapturedByPartialApply);
+
+  std::optional<TrackableValue> trackedBase;
+  if (base)
+    trackedBase =
+        getTrackableValueHelper(base, isAddressCapturedByPartialApply);
+  return {trackedValue, trackedBase};
+}
+
 std::optional<TrackableValue>
 RegionAnalysisValueMap::getTrackableValueForActorIntroducingInst(
     SILInstruction *inst) const {
@@ -752,10 +771,11 @@ RegionAnalysisValueMap::getTrackableValueForActorIntroducingInst(
   return {{iter->first, iter->second}};
 }
 
-std::optional<TrackableValue>
+std::optional<TrackableValueLookupResult>
 RegionAnalysisValueMap::tryToTrackValue(SILValue value) const {
   auto state = getTrackableValue(value);
-  if (state.isNonSendable())
+  if (state.value.isNonSendable() ||
+      (state.base && state.base->isNonSendable()))
     return state;
   return {};
 }
@@ -780,7 +800,7 @@ TrackableValue RegionAnalysisValueMap::getActorIntroducingRepresentative(
 }
 
 bool RegionAnalysisValueMap::valueHasID(SILValue value, bool dumpIfHasNoID) {
-  assert(getTrackableValue(value).isNonSendable() &&
+  assert(getTrackableValue(value).value.isNonSendable() &&
          "Can only accept non-Sendable values");
   bool hasID = equivalenceClassValuesToState.count(value);
   if (!hasID && dumpIfHasNoID) {
@@ -792,7 +812,7 @@ bool RegionAnalysisValueMap::valueHasID(SILValue value, bool dumpIfHasNoID) {
 }
 
 Element RegionAnalysisValueMap::lookupValueID(SILValue value) {
-  auto state = getTrackableValue(value);
+  auto state = getTrackableValue(value).value;
   assert(state.isNonSendable() &&
          "only non-Sendable values should be entered in the map");
   return state.getID();
@@ -810,20 +830,93 @@ void RegionAnalysisValueMap::print(llvm::raw_ostream &os) const {
   for (auto p : temp) {
     os << "%%" << p.first << ": ";
     auto value = getValueForId(Element(p.first));
-    value->print(os);
+    value->print(getFunction(), os);
   }
 #endif
 }
 
-static SILValue getUnderlyingTrackedObjectValue(SILValue value) {
-  auto *fn = value->getFunction();
-  SILValue result = value;
-  while (true) {
-    SILValue temp = result;
+namespace {
 
-    if (auto *svi = dyn_cast<SingleValueInstruction>(temp)) {
+/// Walk from use->def looking through instructions. We have two goals here:
+/// determining the actual equivilance class representative for the passed in
+/// value and looking more aggressively up through uses (even Sendable ones) to
+/// see if we are potentially accessing a base address value as a result of our
+/// value being loaded. We explain these two below in more detail.
+///
+/// # Determining the equivalence class representative for our initial value
+///
+/// We want to determine the actual underlying object that is meant to be used
+/// as the underlying object for our initial value. This value must either be
+/// Sendable (in case which we take the first one). Or if it is non-Sendable, we
+/// need to walk back through instructions that we consider look through until
+/// we hit a Sendable value. We want to view the non-Sendable value as rooted in
+/// the Sendable value since that Sendable value will likely be global actor
+/// isolated or unchecked Sendable and we want SILIsolationInfo to infer
+/// isolation from that instruction.
+///
+/// # Determining the "base" for our initial value
+///
+/// While the above process would be enough if we lived just in a world of
+/// objects, we have to consider additionally the possibility that our object
+/// value was loaded from a var, a non-copyable let that was captured, or an
+/// address only type. In that case, even though generally the frontend performs
+/// all transformations before loading:
+///
+/// ```sil
+/// %0 = alloc_stack $Type
+/// %1 = struct_element_addr %0, $Type, #Type.field
+/// %2 = load [copy] %1 : $FieldType
+/// ```
+///
+/// To truly be complete, we need to be able to handle cases where the frontend
+/// has instead emitted the projection on the object:
+///
+/// ```sil
+/// %0 = alloc_stack $Type
+/// %1 = load_borrow %1 : $Type
+/// %2 = struct_extract %1 : $Type, #Type.field
+/// ```
+///
+/// To ensure that we can always find that base, we need to do some work like we
+/// do in the AddressBaseComputingVisitor: namely we look through sendable
+/// object projections (and object projections in general) until we find what I
+/// term an object base (e.x.: a function argument, an apply result, a cast from
+/// a RawPointer) or a load instruction. If we find a load instruction, then our
+/// caller can know to run AddressBaseComputingVisitor to determine if we are
+/// loading from a box in order to grab the value.
+///
+/// NOTE: The author has only seen this happen so far with unchecked_enum_data,
+/// but relying on the frontend to emit code in a specific manner rather than
+/// coming up with a model that works completely in SIL no matter what the
+/// frontend does is the only way to have a coherent, non-brittle
+/// model. Otherwise, there is an implicit contract in between the frontend and
+/// the optimizer where both are following each other making it easy for the two
+/// to get out of sync.
+struct UnderlyingTrackedObjectValueVisitor {
+  SILValue value;
+
+private:
+  /// Visit \p sourceValue returning a load base if we find one. The actual
+  /// underlying object is value.
+  SILValue visit(SILValue sourceValue) {
+    auto *fn = sourceValue->getFunction();
+
+    // If our result is ever Sendable, we record that as our value if we do
+    // not have a value yet. We always want to take the first one.
+    if (SILIsolationInfo::isSendableType(sourceValue->getType(), fn)) {
+      if (!value) {
+        value = sourceValue;
+      }
+    }
+
+    if (auto *svi = dyn_cast<SingleValueInstruction>(sourceValue)) {
       if (isStaticallyLookThroughInst(svi)) {
-        temp = svi->getOperand(0);
+        if (!value && SILIsolationInfo::isSendableType(svi->getOperand(0)) &&
+            SILIsolationInfo::isNonSendableType(svi)) {
+          value = svi;
+        }
+
+        return svi->getOperand(0);
       }
 
       // If we have a cast and our operand and result are non-Sendable, treat it
@@ -832,78 +925,158 @@ static SILValue getUnderlyingTrackedObjectValue(SILValue value) {
         if (SILIsolationInfo::isNonSendableType(svi->getType(), fn) &&
             SILIsolationInfo::isNonSendableType(svi->getOperand(0)->getType(),
                                                 fn)) {
-          temp = svi->getOperand(0);
+          return svi->getOperand(0);
         }
-      }
 
-      if (isLookThroughIfResultNonSendable(svi)) {
-        if (SILIsolationInfo::isNonSendableType(svi->getType(), fn)) {
-          temp = svi->getOperand(0);
-        }
-      }
-
-      if (isLookThroughIfOperandNonSendable(svi)) {
-        // If our operand is a non-Sendable type, look through this instruction.
-        if (SILIsolationInfo::isNonSendableType(svi->getOperand(0)->getType(),
-                                                fn)) {
-          temp = svi->getOperand(0);
+        if (!value && SILIsolationInfo::isSendableType(svi->getOperand(0)) &&
+            SILIsolationInfo::isNonSendableType(svi)) {
+          value = svi;
         }
       }
     }
 
-    if (auto *inst = temp->getDefiningInstruction()) {
+    if (auto *inst = sourceValue->getDefiningInstruction()) {
       if (isStaticallyLookThroughInst(inst)) {
-        temp = inst->getOperand(0);
-      }
-    }
+        if (!value && SILIsolationInfo::isSendableType(inst->getOperand(0)) &&
+            SILIsolationInfo::isNonSendableType(sourceValue)) {
+          value = sourceValue;
+        }
 
-    if (temp != result) {
-      result = temp;
-      continue;
+        return inst->getOperand(0);
+      }
     }
 
-    return result;
+    return SILValue();
   }
-}
 
-RegionAnalysisValueMap::UnderlyingTrackedValueInfo
-RegionAnalysisValueMap::getUnderlyingTrackedValueHelper(SILValue value) const {
-  // Before a check if the value we are attempting to access is Sendable. In
-  // such a case, just return early.
-  if (!SILIsolationInfo::isNonSendableType(value))
-    return UnderlyingTrackedValueInfo(value);
+public:
+  SILValue visitAll(SILValue sourceValue) {
+    // Before we do anything,
+    if (SILIsolationInfo::isSendableType(sourceValue))
+      value = sourceValue;
+
+    SILValue result = visit(sourceValue);
+    if (!result)
+      return sourceValue;
+
+    while (SILValue nextValue = visit(result))
+      result = nextValue;
 
-  // Look through a project_box, so that we process it like its operand object.
-  if (auto *pbi = dyn_cast<ProjectBoxInst>(value)) {
-    value = pbi->getOperand();
+    return result;
   }
+};
 
-  if (!value->getType().isAddress()) {
-    SILValue underlyingValue = getUnderlyingTrackedObjectValue(value);
+} // namespace
 
-    // If we do not have a load inst, just return the value.
-    if (!isa<LoadInst, LoadBorrowInst>(underlyingValue)) {
-      return UnderlyingTrackedValueInfo(underlyingValue);
-    }
+RegionAnalysisValueMap::UnderlyingTrackedValueInfo
+RegionAnalysisValueMap::getUnderlyingTrackedValueHelperObject(
+    SILValue value) const {
+  // Look through all look through values stopping at any Sendable values.
+  UnderlyingTrackedObjectValueVisitor visitor;
+  SILValue baseValue = visitor.visitAll(value);
+  assert(baseValue->getType().isObject());
 
-    // If we got an address, lets see if we can do even better by looking at the
-    // address.
-    value = cast<SingleValueInstruction>(underlyingValue)->getOperand(0);
+  if (!visitor.value) {
+    return UnderlyingTrackedValueInfo(baseValue);
   }
-  assert(value->getType().isAddress());
 
-  UseDefChainVisitor visitor;
+  assert(visitor.value->getType().isObject());
+  if (visitor.value == baseValue)
+    return UnderlyingTrackedValueInfo(visitor.value);
+  return UnderlyingTrackedValueInfo(visitor.value, baseValue);
+}
+
+RegionAnalysisValueMap::UnderlyingTrackedValueInfo
+RegionAnalysisValueMap::getUnderlyingTrackedValueHelperAddress(
+    SILValue value) const {
+  AddressBaseComputingVisitor visitor;
   SILValue base = visitor.visitAll(value);
   assert(base);
+
+  // If we have an object base...
   if (base->getType().isObject()) {
-    // NOTE: We purposely recurse into the cached version of our computation
-    // rather than recurse into getUnderlyingTrackedObjectValueHelper. This is
-    // safe since we know that value was previously an address so if our base is
-    // an object, it cannot be the same object.
-    return {getUnderlyingTrackedValue(base).value, visitor.actorIsolation};
+    // Recurse.
+    //
+    // NOTE: We purposely recurse into getUnderlyingTrackedValueHelper instead
+    // of getUnderlyingTrackedValue since we could cause an invalidation to
+    // occur in the underlying DenseMap that backs getUnderlyingTrackedValue()
+    // if we insert another entry into the DenseMap.
+    if (!visitor.value)
+      return UnderlyingTrackedValueInfo(getUnderlyingTrackedValueHelper(base));
+
+    // TODO: Should we us the base or value from
+    // getUnderlyingTrackedValueHelperObject as our base?
+    return UnderlyingTrackedValueInfo(
+        visitor.value, getUnderlyingTrackedValueHelper(base).value);
+  }
+
+  // Otherwise, we return the actorIsolation that our visitor found.
+  if (!visitor.value)
+    return UnderlyingTrackedValueInfo(base);
+  return UnderlyingTrackedValueInfo(visitor.value, base);
+}
+
+RegionAnalysisValueMap::UnderlyingTrackedValueInfo
+RegionAnalysisValueMap::getUnderlyingTrackedValueHelper(SILValue value) const {
+  // If we have an address, immediately delegate to the address implementation.
+  if (value->getType().isAddress()) {
+    auto addressInfo = getUnderlyingTrackedValueHelperAddress(value);
+
+    // See if we are returned a value that is a load or a load_borrow. In that
+    // case, we want to continue.
+    if (isa<LoadInst, LoadBorrowInst>(addressInfo.value)) {
+      return getUnderlyingTrackedValueHelper(
+          cast<SingleValueInstruction>(addressInfo.value)->getOperand(0));
+    }
+
+    // If our value is not a load, check if we have a base that is a load. In
+    // such a case, we want to search for a better base.
+    if (llvm::isa_and_nonnull<LoadInst, LoadBorrowInst>(addressInfo.base)) {
+      auto newBase = getUnderlyingTrackedValueHelper(
+          cast<SingleValueInstruction>(addressInfo.base)->getOperand(0));
+      if (newBase.base)
+        return UnderlyingTrackedValueInfo(addressInfo.value, newBase.base);
+      return UnderlyingTrackedValueInfo(addressInfo.value, newBase.value);
+    }
+
+    return addressInfo;
   }
 
-  return {base, visitor.actorIsolation};
+  // Otherwise, we have an object and need to be a little smarter. First try to
+  // find the underlying value and base.
+  //
+  // NOTE: the base and value are guaranteed by invariant to always be different
+  // values. If they are the same, we just return as if we did not have a
+  // base. This ensures that if we both value/base return the same load,
+  // load_borrow, we process it along the no-base path below.
+  UnderlyingTrackedValueInfo objectInfo =
+      getUnderlyingTrackedValueHelperObject(value);
+  assert(objectInfo.value);
+
+  // If we do not have a base...
+  if (!objectInfo.base) {
+    // If we do not have a load or a load_borrow, just return the value
+    // immediately.
+    if (!isa<LoadInst, LoadBorrowInst>(objectInfo.value))
+      return UnderlyingTrackedValueInfo(objectInfo.value);
+
+    // Otherwise, look through the load/load_borrow and process its address.
+    auto *svi = dyn_cast<SingleValueInstruction>(objectInfo.value);
+    return getUnderlyingTrackedValueHelperAddress(svi->getOperand(0));
+  }
+
+  // Ok, we have a value and a base. First check if our base is not a load or
+  // load_borrow. In such a case, we can just return our value.
+  if (!isa<LoadInst, LoadBorrowInst>(objectInfo.base))
+    return UnderlyingTrackedValueInfo(objectInfo.value);
+
+  // If we have a base that is a load or load_borrow, we need to perform the
+  // address helper to find the true base.
+  auto *svi = dyn_cast<SingleValueInstruction>(objectInfo.base);
+  auto addressInfo = getUnderlyingTrackedValueHelperAddress(svi->getOperand(0));
+  if (addressInfo.base)
+    return UnderlyingTrackedValueInfo(objectInfo.value, addressInfo.base);
+  return UnderlyingTrackedValueInfo(objectInfo.value, addressInfo.value);
 }
 
 //===----------------------------------------------------------------------===//
@@ -960,6 +1133,31 @@ bool TrackableValue::isSendingParameter() const {
   return false;
 }
 
+//===----------------------------------------------------------------------===//
+//                      MARK: TrackableValueLookupResult
+//===----------------------------------------------------------------------===//
+
+void TrackableValueLookupResult::print(SILFunction *fn,
+                                       llvm::raw_ostream &os) const {
+  os << "Value:\n";
+  value.print(fn, os);
+  if (base) {
+    os << "Base:\n";
+    base->print(fn, os);
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//                      MARK: UnderlyingTrackedValueInfo
+//===----------------------------------------------------------------------===//
+
+void RegionAnalysisValueMap::UnderlyingTrackedValueInfo::print(
+    llvm::raw_ostream &os) const {
+  os << "RegionAnalysisValueMap.\nValue: " << value;
+  if (base)
+    os << "Base: " << base;
+}
+
 //===----------------------------------------------------------------------===//
 //                      MARK: Partial Apply Reachability
 //===----------------------------------------------------------------------===//
@@ -1083,6 +1281,9 @@ bool PartialApplyReachabilityDataflow::isReachable(SILValue value,
 
   // We were not reachable at entry but are at our exit... walk the block and
   // see if our user is before a gen instruction.
+
+  // To do so, first find the range of pairs in valueToGenInsts that contains
+  // our base value.
   auto genStart = std::lower_bound(
       valueToGenInsts.begin(), valueToGenInsts.end(),
       std::make_pair(baseValue, nullptr),
@@ -1091,20 +1292,29 @@ bool PartialApplyReachabilityDataflow::isReachable(SILValue value,
   if (genStart == valueToGenInsts.end() || genStart->first != baseValue)
     return false;
 
+  // Then determine the end of that range.
   auto genEnd = genStart;
   while (genEnd != valueToGenInsts.end() && genEnd->first == baseValue)
     ++genEnd;
 
   // Walk forward from the beginning of the block to user. If we do not find a
   // gen instruction, then we know the gen occurs after the op.
+  //
+  // NOTE: It is important that we include the user within our range since our
+  // user might also be a gen instruction.
   return llvm::any_of(
-      user->getParent()->getRangeEndingAtInst(user), [&](SILInstruction &inst) {
+      llvm::make_range(user->getParent()->begin(),
+                       std::next(user->getIterator())), [&](SILInstruction &inst) {
+        // Our computation works by computing a lower bound and seeing if we
+        // have (baseValue, inst) within our sorted range.
         auto iter = std::lower_bound(
             genStart, genEnd, std::make_pair(baseValue, &inst),
             [](const std::pair<SILValue, SILInstruction *> &p1,
                const std::pair<SILValue, SILInstruction *> &p2) {
               return p1 < p2;
             });
+
+        // If we did not hit end and found our pair, then we are done.
         return iter != valueToGenInsts.end() && iter->first == baseValue &&
                iter->second == &inst;
       });
@@ -1417,11 +1627,38 @@ struct PartitionOpBuilder {
 
   /// List of partition ops mapped to the current instruction. Used when
   /// generating partition ops.
-  SmallVector<PartitionOp, 8> currentInstPartitionOps;
+  std::vector<PartitionOp> *currentInstPartitionOps = nullptr;
+
+  /// The initial partition op index since the last reset. We use this so that
+  /// we can dump out the partition ops that we generated for a specific
+  /// instruction without needing to waste cycles maintaining a separate
+  /// SmallVector of PartitionOps inside of PartitionOpBuilder.
+  unsigned initialPartitionOpIndex = 0;
+
+  void initialize(std::vector<PartitionOp> &foundPartitionOps) {
+    assert(foundPartitionOps.empty());
+    currentInstPartitionOps = &foundPartitionOps;
+    initialPartitionOpIndex = currentInstPartitionOps->size();
+  }
+
+  SILFunction *getFunction() const {
+    assert(currentInst);
+    return currentInst->getFunction();
+  }
 
   void reset(SILInstruction *inst) {
+    assert(currentInstPartitionOps);
     currentInst = inst;
-    currentInstPartitionOps.clear();
+    initialPartitionOpIndex = currentInstPartitionOps->size();
+  }
+
+  /// Return an ArrayRef containing the PartitionOps associated with the current
+  /// instruction being built.
+  ArrayRef<PartitionOp> getPartitionOpsForCurrentInst() const {
+    assert(currentInstPartitionOps);
+    unsigned numElts =
+        currentInstPartitionOps->size() - initialPartitionOpIndex;
+    return llvm::ArrayRef(*currentInstPartitionOps).take_back(numElts);
   }
 
   Element lookupValueID(SILValue value);
@@ -1429,17 +1666,30 @@ struct PartitionOpBuilder {
 
   Element getActorIntroducingRepresentative(SILIsolationInfo actorIsolation);
 
-  void addAssignFresh(SILValue value) {
-    std::array<Element, 1> values = {lookupValueID(value)};
-    currentInstPartitionOps.emplace_back(
-        PartitionOp::AssignFresh(values, currentInst));
+  void addAssignFresh(TrackableValue value) {
+    if (value.isSendable())
+      return;
+    auto id = lookupValueID(value.getRepresentative().getValue());
+    currentInstPartitionOps->emplace_back(
+        PartitionOp::AssignFresh(id, currentInst));
   }
 
   void addAssignFresh(ArrayRef<SILValue> values) {
-    auto transformedCollection = makeTransformRange(
-        values, [&](SILValue value) { return lookupValueID(value); });
-    currentInstPartitionOps.emplace_back(
-        PartitionOp::AssignFresh(transformedCollection, currentInst));
+    if (values.empty())
+      return;
+
+    auto first = lookupValueID(values.front());
+    currentInstPartitionOps->emplace_back(
+        PartitionOp::AssignFresh(first, currentInst));
+
+    auto transformedCollection =
+        makeTransformRange(values.drop_front(), [&](SILValue value) {
+          return lookupValueID(value);
+        });
+    for (auto id : transformedCollection) {
+      currentInstPartitionOps->emplace_back(
+          PartitionOp::AssignFreshAssign(id, first, currentInst));
+    }
   }
 
   void addAssign(SILValue destValue, Operand *srcOperand) {
@@ -1456,16 +1706,20 @@ struct PartitionOpBuilder {
       return;
     }
 
-    currentInstPartitionOps.emplace_back(
+    currentInstPartitionOps->emplace_back(
         PartitionOp::Assign(lookupValueID(destValue),
                             lookupValueID(srcOperand->get()), srcOperand));
   }
 
-  void addSend(SILValue representative, Operand *op) {
+  void addSend(TrackableValue value, Operand *op) {
+    if (value.isSendable())
+      return;
+
+    auto representative = value.getRepresentative().getValue();
     assert(valueHasID(representative) &&
            "sent value should already have been encountered");
 
-    currentInstPartitionOps.emplace_back(
+    currentInstPartitionOps->emplace_back(
         PartitionOp::Send(lookupValueID(representative), op));
   }
 
@@ -1473,24 +1727,26 @@ struct PartitionOpBuilder {
     assert(valueHasID(representative) &&
            "value should already have been encountered");
 
-    currentInstPartitionOps.emplace_back(
+    currentInstPartitionOps->emplace_back(
         PartitionOp::UndoSend(lookupValueID(representative), unsendingInst));
   }
 
-  void addMerge(SILValue destValue, Operand *srcOperand) {
-    assert(valueHasID(destValue, /*dumpIfHasNoID=*/true) &&
+  void addMerge(TrackableValue destValue, Operand *srcOperand) {
+    if (destValue.isSendable())
+      return;
+    auto rep = destValue.getRepresentative().getValue();
+    assert(valueHasID(rep, /*dumpIfHasNoID=*/true) &&
            valueHasID(srcOperand->get(), /*dumpIfHasNoID=*/true) &&
            "merged values should already have been encountered");
 
-    if (lookupValueID(destValue) == lookupValueID(srcOperand->get()))
+    if (lookupValueID(rep) == lookupValueID(srcOperand->get()))
       return;
 
-    currentInstPartitionOps.emplace_back(
-        PartitionOp::Merge(lookupValueID(destValue),
-                           lookupValueID(srcOperand->get()), srcOperand));
+    currentInstPartitionOps->emplace_back(PartitionOp::Merge(
+        lookupValueID(rep), lookupValueID(srcOperand->get()), srcOperand));
   }
 
-  /// Mark \p value artifically as being part of an actor isolated region by
+  /// Mark \p value artifically as being part of an actor-isolated region by
   /// introducing a new fake actor introducing representative and merging them.
   void addActorIntroducingInst(SILValue sourceValue, Operand *sourceOperand,
                                SILIsolationInfo actorIsolation) {
@@ -1498,24 +1754,33 @@ struct PartitionOpBuilder {
            "merged values should already have been encountered");
 
     auto elt = getActorIntroducingRepresentative(actorIsolation);
-    currentInstPartitionOps.emplace_back(
+    currentInstPartitionOps->emplace_back(
         PartitionOp::AssignFresh(elt, currentInst));
-    currentInstPartitionOps.emplace_back(
+    currentInstPartitionOps->emplace_back(
         PartitionOp::Merge(lookupValueID(sourceValue), elt, sourceOperand));
   }
 
-  void addRequire(SILValue value) {
-    assert(valueHasID(value, /*dumpIfHasNoID=*/true) &&
-           "required value should already have been encountered");
-    currentInstPartitionOps.emplace_back(
-        PartitionOp::Require(lookupValueID(value), currentInst));
+  void addRequire(TrackableValueLookupResult value);
+
+private:
+  void addRequire(TrackableValue value, PartitionOp::Options options = {});
+
+  void addRequire(std::optional<TrackableValue> value,
+                  PartitionOp::Options options = {}) {
+    if (!value)
+      return;
+    addRequire(*value, options);
   }
 
-  void addInOutSendingAtFunctionExit(SILValue value) {
-    assert(valueHasID(value, /*dumpIfHasNoID=*/true) &&
+public:
+  void addInOutSendingAtFunctionExit(TrackableValue value) {
+    if (value.isSendable())
+      return;
+    auto rep = value.getRepresentative().getValue();
+    assert(valueHasID(rep, /*dumpIfHasNoID=*/true) &&
            "required value should already have been encountered");
-    currentInstPartitionOps.emplace_back(
-        PartitionOp::InOutSendingAtFunctionExit(lookupValueID(value),
+    currentInstPartitionOps->emplace_back(
+        PartitionOp::InOutSendingAtFunctionExit(lookupValueID(rep),
                                                 currentInst));
   }
 
@@ -1524,13 +1789,16 @@ struct PartitionOpBuilder {
       llvm::report_fatal_error(
           "RegionIsolation: Aborting on unknown pattern match error");
     }
-    currentInstPartitionOps.emplace_back(
+    currentInstPartitionOps->emplace_back(
         PartitionOp::UnknownPatternError(lookupValueID(value), currentInst));
   }
 
-  void addNonSendableIsolationCrossingResultError(SILValue value) {
-    currentInstPartitionOps.emplace_back(
-        PartitionOp::NonSendableIsolationCrossingResult(lookupValueID(value),
+  void addNonSendableIsolationCrossingResultError(TrackableValue value) {
+    if (value.isSendable())
+      return;
+    auto rep = value.getRepresentative().getValue();
+    currentInstPartitionOps->emplace_back(
+        PartitionOp::NonSendableIsolationCrossingResult(lookupValueID(rep),
                                                         currentInst));
   }
 
@@ -1548,7 +1816,7 @@ struct PartitionOpBuilder {
 namespace {
 
 enum class TranslationSemantics {
-  /// An instruction that does not affect region based state or if it does we
+  /// An instruction that does not affect region-based state or if it does we
   /// would like to error on some other use. An example would be something
   /// like end_borrow, inject_enum_addr, or alloc_global. We do not produce
   /// any partition op.
@@ -1705,8 +1973,11 @@ class PartitionOpTranslator {
 
   SILFunction *function;
 
-  /// A cache of argument IDs.
-  std::optional<Partition> functionArgPartition;
+  /// The initial partition of the entry block.
+  ///
+  /// This contains a single region for non-sending parameters as well as
+  /// separate regions for each sending parameter.
+  std::optional<Partition> initialEntryBlockPartition;
 
   /// A builder struct that we use to convert individual instructions into lists
   /// of PartitionOps.
@@ -1748,7 +2019,8 @@ class PartitionOpTranslator {
                 isNonSendableType(val->getType())) {
               auto trackVal = getTrackableValue(val, true);
               (void)trackVal;
-              REGIONBASEDISOLATION_LOG(trackVal.print(llvm::dbgs()));
+              REGIONBASEDISOLATION_LOG(
+                  trackVal.print(val->getFunction(), llvm::dbgs()));
               continue;
             }
             if (auto *pbi = dyn_cast<ProjectBoxInst>(val)) {
@@ -1771,7 +2043,7 @@ class PartitionOpTranslator {
   PartitionOpTranslator(SILFunction *function, PostOrderFunctionInfo *pofi,
                         RegionAnalysisValueMap &valueMap,
                         IsolationHistory::Factory &historyFactory)
-      : function(function), functionArgPartition(), builder(),
+      : function(function), initialEntryBlockPartition(),
         partialApplyReachabilityDataflow(function, valueMap, pofi),
         valueMap(valueMap) {
     builder.translator = this;
@@ -1794,8 +2066,8 @@ class PartitionOpTranslator {
     auto functionArguments = function->getArguments();
     if (functionArguments.empty()) {
       REGIONBASEDISOLATION_LOG(llvm::dbgs() << "    None.\n");
-      functionArgPartition = Partition::singleRegion(SILLocation::invalid(), {},
-                                                     historyFactory.get());
+      initialEntryBlockPartition = Partition::singleRegion(
+          SILLocation::invalid(), {}, historyFactory.get());
       return;
     }
 
@@ -1803,34 +2075,39 @@ class PartitionOpTranslator {
     llvm::SmallVector<Element, 8> nonSendableSeparateIndices;
     for (SILArgument *arg : functionArguments) {
       // This will decide what the isolation region is.
-      if (auto state = tryToTrackValue(arg)) {
+      if (auto lookupResult = tryToTrackValue(arg)) {
+        auto value = lookupResult->value;
+        assert(value.isNonSendable() &&
+               "We should never see a sendable function argument from "
+               "tryToTrackValue since we will never have a non-Sendable base");
+
         // If we can send our parameter, just add it to
         // nonSendableSeparateIndices.
         //
         // NOTE: We do not support today the ability to have multiple parameters
         // send together as part of the same region.
         if (canFunctionArgumentBeSent(cast<SILFunctionArgument>(arg))) {
-          REGIONBASEDISOLATION_LOG(llvm::dbgs() << "    %%" << state->getID()
+          REGIONBASEDISOLATION_LOG(llvm::dbgs() << "    %%" << value.getID()
                                                 << " (sending): " << *arg);
-          nonSendableSeparateIndices.push_back(state->getID());
+          nonSendableSeparateIndices.push_back(value.getID());
           continue;
         }
 
         // Otherwise, it is one of our merged parameters. Add it to the never
         // send list and to the region join list.
         REGIONBASEDISOLATION_LOG(
-            llvm::dbgs() << "    %%" << state->getID() << ": ";
-            state->print(llvm::dbgs()); llvm::dbgs() << *arg);
-        nonSendableJoinedIndices.push_back(state->getID());
+            llvm::dbgs() << "    %%" << value.getID() << ": ";
+            value.print(function, llvm::dbgs()); llvm::dbgs() << *arg);
+        nonSendableJoinedIndices.push_back(value.getID());
       } else {
         REGIONBASEDISOLATION_LOG(llvm::dbgs() << "    Sendable: " << *arg);
       }
     }
 
-    functionArgPartition = Partition::singleRegion(
+    initialEntryBlockPartition = Partition::singleRegion(
         SILLocation::invalid(), nonSendableJoinedIndices, historyFactory.get());
     for (Element elt : nonSendableSeparateIndices) {
-      functionArgPartition->trackNewElement(elt);
+      initialEntryBlockPartition->trackNewElement(elt);
     }
   }
 
@@ -1853,13 +2130,14 @@ class PartitionOpTranslator {
     return SILIsolationInfo::isNonSendableType(type, function);
   }
 
-  TrackableValue
+  TrackableValueLookupResult
   getTrackableValue(SILValue value,
                     bool isAddressCapturedByPartialApply = false) {
     return valueMap.getTrackableValue(value, isAddressCapturedByPartialApply);
   }
 
-  std::optional<TrackableValue> tryToTrackValue(SILValue value) const {
+  std::optional<TrackableValueLookupResult>
+  tryToTrackValue(SILValue value) const {
     return valueMap.tryToTrackValue(value);
   }
 
@@ -1898,8 +2176,10 @@ class PartitionOpTranslator {
 public:
   /// Return the partition consisting of all function arguments.
   ///
-  /// Used to initialize the entry blocko of our analysis.
-  const Partition &getEntryPartition() const { return *functionArgPartition; }
+  /// Used to initialize the initial partition of the entry block of the CFG.
+  const Partition &getInitialEntryPartition() const {
+    return *initialEntryBlockPartition;
+  }
 
   /// Get the results of an apply instruction.
   ///
@@ -1934,11 +2214,11 @@ class PartitionOpTranslator {
   /// the same value.
   template <typename TargetRange, typename SourceRange>
   void
-  translateSILMultiAssign(const TargetRange &resultValues,
+  translateSILMultiAssign(const TargetRange &directResultValues,
                           const SourceRange &sourceValues,
                           SILIsolationInfo resultIsolationInfoOverride = {},
                           bool requireSrcValues = true) {
-    SmallVector<std::pair<Operand *, SILValue>, 8> assignOperands;
+    SmallVector<std::pair<Operand *, TrackableValue>, 8> assignOperands;
     SmallVector<SILValue, 8> assignResults;
 
     // A helper we use to emit an unknown patten error if our merge is
@@ -1952,15 +2232,38 @@ class PartitionOpTranslator {
       mergedInfo = SILDynamicMergedIsolationInfo::getDisconnected(false);
     }
 
+    // For each operand...
     for (Operand *srcOperand : sourceValues) {
+      // Grab our value...
       auto src = srcOperand->get();
-      if (auto value = tryToTrackValue(src)) {
-        assignOperands.push_back(
-            {srcOperand, value->getRepresentative().getValue()});
+
+      // Perform our lookup result.
+      if (auto lookupResult = tryToTrackValue(src)) {
+        auto value = lookupResult->value;
+
+        // If our value is non-Sendable require it and if we have a base and
+        // that base is non-Sendable, require that as well.
+        //
+        // DISCUSSION: The reason that this may be useful is for special
+        // instructions like store_borrow. On the one hand, we want store_borrow
+        // to act like a store in the sense that we want to combine the regions
+        // of its src and dest... but at the same time, we do not want to treat
+        // the store itself as a use of its parent value. We want that to be any
+        // subsequent uses of the store_borrow.
+        if (requireSrcValues) {
+          builder.addRequire(*lookupResult);
+        }
+
+        // If our value was actually Sendable, skip it, we do not want to merge
+        // anything.
+        if (value.isSendable())
+          continue;
+
+        assignOperands.push_back({srcOperand, value});
         auto originalMergedInfo = mergedInfo;
         (void)originalMergedInfo;
         if (mergedInfo)
-          mergedInfo = mergedInfo->merge(value->getIsolationRegionInfo());
+          mergedInfo = mergedInfo->merge(value.getIsolationRegionInfo());
 
         // If we fail to merge, then we have an incompatibility in between some
         // of our arguments (consider isolated to different actors) or with the
@@ -1969,14 +2272,15 @@ class PartitionOpTranslator {
           REGIONBASEDISOLATION_LOG(
               llvm::dbgs() << "Merge Failure!\n"
                            << "Original Info: ";
-              if (originalMergedInfo)
-                  originalMergedInfo->printForDiagnostics(llvm::dbgs());
+              if (originalMergedInfo) originalMergedInfo->printForDiagnostics(
+                  builder.getFunction(), llvm::dbgs());
               else llvm::dbgs() << "nil";
               llvm::dbgs() << "\nValue Rep: "
-                           << value->getRepresentative().getValue();
+                           << value.getRepresentative().getValue();
               llvm::dbgs() << "Original Src: " << src;
               llvm::dbgs() << "Value Info: ";
-              value->getIsolationRegionInfo().printForDiagnostics(llvm::dbgs());
+              value.getIsolationRegionInfo().printForDiagnostics(
+                  builder.getFunction(), llvm::dbgs());
               llvm::dbgs() << "\n");
           builder.addUnknownPatternError(src);
           continue;
@@ -1984,7 +2288,12 @@ class PartitionOpTranslator {
       }
     }
 
-    for (SILValue result : resultValues) {
+    // Merge all srcs.
+    for (unsigned i = 1; i < assignOperands.size(); i++) {
+      builder.addMerge(assignOperands[i - 1].second, assignOperands[i].first);
+    }
+
+    for (SILValue result : directResultValues) {
       // If we had isolation info explicitly passed in... use our
       // resultIsolationInfoError. Otherwise, we want to infer.
       if (resultIsolationInfoOverride) {
@@ -1999,29 +2308,15 @@ class PartitionOpTranslator {
               nonSendableValue->first.getRepresentative().getValue());
         }
       } else {
-        if (auto value = tryToTrackValue(result)) {
-          assignResults.push_back(value->getRepresentative().getValue());
+        if (auto lookupResult = tryToTrackValue(result)) {
+          if (lookupResult->value.isSendable())
+            continue;
+          auto value = lookupResult->value;
+          assignResults.push_back(value.getRepresentative().getValue());
         }
       }
     }
 
-    // Require all srcs if we are supposed to. (By default we do).
-    //
-    // DISCUSSION: The reason that this may be useful is for special
-    // instructions like store_borrow. On the one hand, we want store_borrow to
-    // act like a store in the sense that we want to combine the regions of its
-    // src and dest... but at the same time, we do not want to treat the store
-    // itself as a use of its parent value. We want that to be any subsequent
-    // uses of the store_borrow.
-    if (requireSrcValues)
-      for (auto src : assignOperands)
-        builder.addRequire(src.second);
-
-    // Merge all srcs.
-    for (unsigned i = 1; i < assignOperands.size(); i++) {
-      builder.addMerge(assignOperands[i - 1].second, assignOperands[i].first);
-    }
-
     // If we do not have any non sendable results, return early.
     if (assignResults.empty()) {
       // If we did not have any non-Sendable results and we did have
@@ -2034,9 +2329,9 @@ class PartitionOpTranslator {
       // passed in a specific isolation info unlike earlier when processing
       // actual results.
       if (assignOperands.size() && resultIsolationInfoOverride) {
-        builder.addActorIntroducingInst(assignOperands.back().second,
-                                        assignOperands.back().first,
-                                        resultIsolationInfoOverride);
+        builder.addActorIntroducingInst(
+            assignOperands.back().second.getRepresentative().getValue(),
+            assignOperands.back().first, resultIsolationInfoOverride);
       }
 
       return;
@@ -2072,7 +2367,8 @@ class PartitionOpTranslator {
     // Just track the result of the builtin inst as an assign fresh. We do this
     // so we properly track the partial_apply get. We already sent the
     // parameters.
-    builder.addAssignFresh(bi);
+    if (auto lookupResult = tryToTrackValue(bi))
+      builder.addAssignFresh(lookupResult->value);
   }
 
   /// For discussion on how we handle async let, please see the comment on
@@ -2084,7 +2380,7 @@ class PartitionOpTranslator {
 
     // If we didn't find a partial_apply, then we must have had a
     // thin_to_thick_function meaning we did not capture anything.
-    if (source->is<ThinToThickFunctionInst *>())
+    if (isa<ThinToThickFunctionInst *>(source.value()))
       return;
 
     // If our partial_apply was Sendable, then Sema should have checked that
@@ -2092,17 +2388,28 @@ class PartitionOpTranslator {
     // error earlier.
     assert(bool(source.value()) &&
            "AsyncLet Get should always have a derivable partial_apply");
-    auto *pai = source->get<PartialApplyInst *>();
+    auto *pai = cast<PartialApplyInst *>(source.value());
     if (pai->getFunctionType()->isSendable())
       return;
 
     ApplySite applySite(pai);
+
     // For each of our partial apply operands...
     for (auto pair : llvm::enumerate(applySite.getArgumentOperands())) {
       Operand &op = pair.value();
 
       // If we are tracking the value...
-      if (auto trackedArgValue = tryToTrackValue(op.get())) {
+      if (auto lookupResult = tryToTrackValue(op.get())) {
+        auto trackedArgValue = lookupResult->value;
+
+        // If we see that our arg value was Sendable, continue. We do not need
+        // to consider a base here since when we capture variables, we always
+        // capture them completely by reference meaning we will actually capture
+        // the base.
+        if (trackedArgValue.isSendable()) {
+          assert(!lookupResult->base.has_value() && "Should never have a base");
+          continue;
+        }
 
         // Gather the isolation info from the AST for this operand...
         InferredCallerArgumentTypeInfo typeInfo;
@@ -2123,8 +2430,7 @@ class PartitionOpTranslator {
                 }))
           continue;
 
-        builder.addUndoSend(trackedArgValue->getRepresentative().getValue(),
-                            ai);
+        builder.addUndoSend(trackedArgValue.getRepresentative().getValue(), ai);
       }
     }
   }
@@ -2143,14 +2449,15 @@ class PartitionOpTranslator {
     // _ = await y
     // useValue(x2)
     for (auto &op : ApplySite(pai).getArgumentOperands()) {
-      if (auto trackedArgValue = tryToTrackValue(op.get())) {
-        builder.addRequire(trackedArgValue->getRepresentative().getValue());
-        builder.addSend(trackedArgValue->getRepresentative().getValue(), &op);
+      if (auto lookupResult = tryToTrackValue(op.get())) {
+        builder.addRequire(*lookupResult);
+        builder.addSend(lookupResult->value, &op);
       }
     }
 
     // Then mark our partial_apply result as being returned fresh.
-    builder.addAssignFresh(pai);
+    if (auto lookupResult = tryToTrackValue(pai))
+      builder.addAssignFresh(lookupResult->value);
   }
 
   /// Handles the semantics for SIL applies that cross isolation.
@@ -2165,11 +2472,11 @@ class PartitionOpTranslator {
     // For each argument operand.
     for (auto &op : applySite.getArgumentOperands()) {
       // See if we tracked it.
-      if (auto value = tryToTrackValue(op.get())) {
+      if (auto lookupResult = tryToTrackValue(op.get())) {
         // If we are tracking it, sent it and if it is actor derived, mark
         // our partial apply as actor derived.
-        builder.addRequire(value->getRepresentative().getValue());
-        builder.addSend(value->getRepresentative().getValue(), &op);
+        builder.addRequire(*lookupResult);
+        builder.addSend(lookupResult->value, &op);
       }
     }
 
@@ -2191,7 +2498,7 @@ class PartitionOpTranslator {
   void translateSILPartialApply(PartialApplyInst *pai) {
     // First check if our partial apply is Sendable and not global actor
     // isolated. In such a case, we will have emitted an earlier warning in Sema
-    // and can return early. If we have a global actor isolated partial_apply,
+    // and can return early. If we have a global-actor-isolated partial_apply,
     // we can be looser and can use region isolation since we know that the
     // Sendable closure will be executed serially due to the closure having to
     // run on the global actor queue meaning that we do not have to worry about
@@ -2220,7 +2527,8 @@ class PartitionOpTranslator {
       }
     }
 
-    if (auto isolationRegionInfo = SILIsolationInfo::get(pai)) {
+    if (auto isolationRegionInfo = SILIsolationInfo::get(pai);
+        isolationRegionInfo && !isolationRegionInfo.isDisconnected()) {
       return translateIsolatedPartialApply(pai, isolationRegionInfo);
     }
 
@@ -2231,10 +2539,9 @@ class PartitionOpTranslator {
   }
 
   void translateCreateAsyncTask(BuiltinInst *bi) {
-    if (auto value = tryToTrackValue(bi->getOperand(1))) {
-      builder.addRequire(value->getRepresentative().getValue());
-      builder.addSend(value->getRepresentative().getValue(),
-                      &bi->getAllOperands()[1]);
+    if (auto lookupResult = tryToTrackValue(bi->getOperand(1))) {
+      builder.addRequire(*lookupResult);
+      builder.addSend(lookupResult->value, &bi->getAllOperands()[1]);
     }
   }
 
@@ -2274,10 +2581,12 @@ class PartitionOpTranslator {
             continue;
           }
 
-          if (auto value = tryToTrackValue(op.get())) {
-            builder.addRequire(value->getRepresentative().getValue());
-            builder.addSend(value->getRepresentative().getValue(), &op);
-            continue;
+          // Attempt to lookup the value we are passing as sending. We want to
+          // require/send value if it is non-Sendable and require its base if it
+          // is non-Sendable as well.
+          if (auto lookupResult = tryToTrackValue(op.get())) {
+            builder.addRequire(*lookupResult);
+            builder.addSend(lookupResult->value, &op);
           }
         } else {
           nonSendingParameters.push_back(&op);
@@ -2292,9 +2601,9 @@ class PartitionOpTranslator {
       auto &selfOperand = fas.getSelfArgumentOperand();
       if (fas.getArgumentParameterInfo(selfOperand)
               .hasOption(SILParameterInfo::Sending)) {
-        if (auto value = tryToTrackValue(selfOperand.get())) {
-          builder.addRequire(value->getRepresentative().getValue());
-          builder.addSend(value->getRepresentative().getValue(), &selfOperand);
+        if (auto lookupResult = tryToTrackValue(selfOperand.get())) {
+          builder.addRequire(*lookupResult);
+          builder.addSend(lookupResult->value, &selfOperand);
         }
       } else {
         nonSendingParameters.push_back(&selfOperand);
@@ -2308,8 +2617,8 @@ class PartitionOpTranslator {
     // at the point of application. Otherwise, we will not emit errors if the
     // closure before this function application is already in the same region as
     // a sent value. In such a case, the function application must error.
-    if (auto value = tryToTrackValue(fas.getCallee())) {
-      builder.addRequire(value->getRepresentative().getValue());
+    if (auto calleeResult = tryToTrackValue(fas.getCallee())) {
+      builder.addRequire(*calleeResult);
     }
 
     SmallVector<SILValue, 8> applyResults;
@@ -2331,15 +2640,15 @@ class PartitionOpTranslator {
 
     // Sending direct results.
     for (SILValue result : applyResults) {
-      if (auto value = tryToTrackValue(result)) {
-        builder.addAssignFresh(value->getRepresentative().getValue());
+      if (auto lookupResult = tryToTrackValue(result)) {
+        builder.addAssignFresh(lookupResult->value);
       }
     }
 
     // Sending indirect results.
     for (Operand *op : sendingIndirectResults) {
-      if (auto value = tryToTrackValue(op->get())) {
-        builder.addAssignFresh(value->getRepresentative().getValue());
+      if (auto lookupResult = tryToTrackValue(op->get())) {
+        builder.addAssignFresh(lookupResult->value);
       }
     }
   }
@@ -2382,21 +2691,23 @@ class PartitionOpTranslator {
   /// Semantically this causes all arguments of the applysite to be sent.
   void translateIsolationCrossingSILApply(FullApplySite applySite) {
     // Require all operands first before we emit a send.
-    for (auto op : applySite.getArguments())
-      if (auto value = tryToTrackValue(op))
-        builder.addRequire(value->getRepresentative().getValue());
+    for (auto op : applySite.getArguments()) {
+      if (auto lookupResult = tryToTrackValue(op)) {
+        builder.addRequire(*lookupResult);
+      }
+    }
 
     auto handleSILOperands = [&](MutableArrayRef<Operand> operands) {
       for (auto &op : operands) {
-        if (auto value = tryToTrackValue(op.get())) {
-          builder.addSend(value->getRepresentative().getValue(), &op);
+        if (auto lookupResult = tryToTrackValue(op.get())) {
+          builder.addSend(lookupResult->value, &op);
         }
       }
     };
 
     auto handleSILSelf = [&](Operand *self) {
-      if (auto value = tryToTrackValue(self->get())) {
-        builder.addSend(value->getRepresentative().getValue(), self);
+      if (auto lookupResult = tryToTrackValue(self->get())) {
+        builder.addSend(lookupResult->value, self);
       }
     };
 
@@ -2440,11 +2751,11 @@ class PartitionOpTranslator {
                            .isNonisolated());
 
     for (auto result : applyResults) {
-      if (auto value = tryToTrackValue(result)) {
-        builder.addAssignFresh(value->getRepresentative().getValue());
+      if (auto lookupResult = tryToTrackValue(result)) {
+        builder.addAssignFresh(lookupResult->value);
         if (emitIsolationCrossingResultError)
           builder.addNonSendableIsolationCrossingResultError(
-              value->getRepresentative().getValue());
+              lookupResult->value);
       }
     }
 
@@ -2453,9 +2764,9 @@ class PartitionOpTranslator {
     // non-Sendable.
     if (emitIsolationCrossingResultError) {
       for (auto result : applySite.getIndirectSILResults()) {
-        if (auto value = tryToTrackValue(result)) {
+        if (auto lookupResult = tryToTrackValue(result)) {
           builder.addNonSendableIsolationCrossingResultError(
-              value->getRepresentative().getValue());
+              lookupResult->value);
         }
       }
     }
@@ -2463,12 +2774,22 @@ class PartitionOpTranslator {
 
   template <typename DestValues>
   void translateSILLookThrough(DestValues destValues, SILValue src) {
-    auto srcID = tryToTrackValue(src);
+    auto srcResult = tryToTrackValue(src);
 
     for (SILValue dest : destValues) {
-      auto destID = tryToTrackValue(dest);
-      assert(((!destID || !srcID) || destID->getID() == srcID->getID()) &&
-             "srcID and dstID are different?!");
+      // If we have a non-Sendable result and a Sendable src, we assign fresh.
+      if (auto destResult = tryToTrackValue(dest)) {
+        if (!srcResult || srcResult->value.isSendable()) {
+          builder.addAssignFresh(destResult->value);
+          continue;
+        }
+
+        // Otherwise, we do a real look through.
+        assert(((!destResult || !srcResult || destResult->value.isSendable() ||
+                 srcResult->value.isSendable()) ||
+                destResult->value.getID() == srcResult->value.getID()) &&
+               "srcID and dstID are different?!");
+      }
     }
   }
 
@@ -2483,18 +2804,37 @@ class PartitionOpTranslator {
   /// PartitionOp. Doing such a thing obscures what is actually happening.
   template <>
   void translateSILLookThrough<SILValue>(SILValue dest, SILValue src) {
-    auto srcID = tryToTrackValue(src);
-    auto destID = tryToTrackValue(dest);
-    assert(((!destID || !srcID) || destID->getID() == srcID->getID()) &&
-           "srcID and dstID are different?!");
+    auto srcResult = tryToTrackValue(src);
+
+    if (auto destResult = tryToTrackValue(dest)) {
+      if (!srcResult || srcResult->value.isSendable()) {
+        builder.addAssignFresh(destResult->value);
+        return;
+      }
+
+      // Otherwise, we do a real look through.
+      assert(((!srcResult || destResult->value.isSendable() ||
+               srcResult->value.isSendable()) ||
+              destResult->value.getID() == srcResult->value.getID()) &&
+             "srcID and dstID are different?!");
+    }
   }
 
   void translateSILLookThrough(SingleValueInstruction *svi) {
     assert(svi->getNumRealOperands() == 1);
-    auto srcID = tryToTrackValue(svi->getOperand(0));
-    auto destID = tryToTrackValue(svi);
-    assert(((!destID || !srcID) || destID->getID() == srcID->getID()) &&
-           "srcID and dstID are different?!");
+    auto srcResult = tryToTrackValue(svi->getOperand(0));
+    if (auto destResult = tryToTrackValue(svi)) {
+      if (!srcResult || srcResult->value.isSendable()) {
+        builder.addAssignFresh(destResult->value);
+        return;
+      }
+
+      // Otherwise, we do a real look through.
+      assert(((!srcResult || destResult->value.isSendable() ||
+               srcResult->value.isSendable()) ||
+              destResult->value.getID() == srcResult->value.getID()) &&
+             "srcID and dstID are different?!");
+    }
   }
 
   template <typename Collection>
@@ -2535,72 +2875,77 @@ class PartitionOpTranslator {
 
   template <typename Collection>
   void translateSILMerge(SILValue dest, Collection srcCollection,
-                         bool requireOperands = true) {
-    auto trackableDest = tryToTrackValue(dest);
-    if (!trackableDest)
+                         bool requireOperands,
+                         SILIsolationInfo resultIsolationInfoOverride = {}) {
+    auto destResult =  tryToTrackValue(dest);
+    if (!destResult)
       return;
+
+    if (requireOperands) {
+      builder.addRequire(*destResult);
+
+      if (resultIsolationInfoOverride && !srcCollection.empty()) {
+        using std::begin;
+        builder.addActorIntroducingInst(dest, *begin(srcCollection), resultIsolationInfoOverride);
+      }
+    }
+
     for (Operand *op : srcCollection) {
-      if (auto trackableSrc = tryToTrackValue(op->get())) {
+      // If we have a trackable src, we need to require both if asked to and
+      // then merge the dest/src.
+      if (auto srcResult = tryToTrackValue(op->get())) {
         if (requireOperands) {
-          builder.addRequire(trackableSrc->getRepresentative().getValue());
-          builder.addRequire(trackableDest->getRepresentative().getValue());
+          builder.addRequire(*srcResult);
         }
-        builder.addMerge(trackableDest->getRepresentative().getValue(), op);
+
+        if (srcResult->value.isNonSendable())
+          builder.addMerge(destResult->value, op);
       }
     }
   }
 
   template <>
   void translateSILMerge<Operand *>(SILValue dest, Operand *src,
-                                    bool requireOperands) {
+                                    bool requireOperands,
+                                    SILIsolationInfo resultIsolationInfoOverride) {
     return translateSILMerge(dest, TinyPtrVector<Operand *>(src),
-                             requireOperands);
+                             requireOperands, resultIsolationInfoOverride);
   }
 
   void translateSILMerge(MutableArrayRef<Operand> array,
-                         bool requireOperands = true) {
+                         bool requireOperands,
+                         SILIsolationInfo resultIsolationInfoOverride = {}) {
     if (array.size() < 2)
       return;
 
-    auto trackableDest = tryToTrackValue(array.front().get());
-    if (!trackableDest)
-      return;
-    for (Operand &op : array.drop_front()) {
-      if (auto trackableSrc = tryToTrackValue(op.get())) {
-        if (requireOperands) {
-          builder.addRequire(trackableSrc->getRepresentative().getValue());
-          builder.addRequire(trackableDest->getRepresentative().getValue());
-        }
-        builder.addMerge(trackableDest->getRepresentative().getValue(), &op);
+    std::optional<TrackableValueLookupResult> destResult;
+    if (resultIsolationInfoOverride) {
+      if (auto nonSendableValue = initializeTrackedValue(
+              array.front().get(), resultIsolationInfoOverride)) {
+        destResult = TrackableValueLookupResult{
+            nonSendableValue->first, std::nullopt};
       }
+    } else {
+      destResult = tryToTrackValue(array.front().get());
     }
-  }
 
-  void translateSILAssignmentToSendingParameter(TrackableValue destRoot,
-                                                Operand *destOperand,
-                                                TrackableValue srcRoot,
-                                                Operand *srcOperand) {
-    assert(isa<AllocStackInst>(destRoot.getRepresentative().getValue()) &&
-           "Destination should always be an alloc_stack");
+    if (!destResult)
+      return;
 
-    // Send src. This ensures that we cannot use src again locally in this
-    // function... which makes sense since its value is now in the 'sending'
-    // parameter.
-    builder.addRequire(srcRoot.getRepresentative().getValue());
-    builder.addSend(srcRoot.getRepresentative().getValue(), srcOperand);
+    if (requireOperands) {
+      builder.addRequire(*destResult);
+    }
 
-    // Then check if we are assigning into an aggregate projection. In such a
-    // case, we want to ensure that we keep tracking the elements already in the
-    // region of sending. This is more conservative than we need to be
-    // (since we could forget anything reachable from the aggregate
-    // field)... but being more conservative is ok.
-    if (isProjectedFromAggregate(destOperand->get()))
-      return;
+    for (Operand &op : array.drop_front()) {
+      if (auto srcResult = tryToTrackValue(op.get())) {
+        if (requireOperands) {
+          builder.addRequire(*srcResult);
+        }
 
-    // If we are assigning over the entire value though, we perform an assign
-    // fresh since we are guaranteed that any value that could be referenced via
-    // the old value is gone.
-    builder.addAssignFresh(destRoot.getRepresentative().getValue());
+        if (srcResult->value.isNonSendable())
+          builder.addMerge(destResult->value, &op);
+      }
+    }
   }
 
   /// If \p dest is known to be unaliased (computed through a combination of
@@ -2608,10 +2953,11 @@ class PartitionOpTranslator {
   /// captures by applications), then these can be treated as assignments of \p
   /// dest to src. If the \p dest could be aliased, then we must instead treat
   /// them as merges, to ensure any aliases of \p dest are also updated.
-  void translateSILStore(Operand *dest, Operand *src) {
+  void translateSILStore(Operand *dest, Operand *src,
+                          SILIsolationInfo resultIsolationInfoOverride = {}) {
     SILValue destValue = dest->get();
 
-    if (auto nonSendableDest = tryToTrackValue(destValue)) {
+    if (auto destResult = tryToTrackValue(destValue)) {
       // In the following situations, we can perform an assign:
       //
       // 1. A store to unaliased storage.
@@ -2623,12 +2969,17 @@ class PartitionOpTranslator {
       // specifically in this projection... but that is better than
       // miscompiling. For memory like this, we probably need to track it on a
       // per field basis to allow for us to assign.
-      if (nonSendableDest.value().isNoAlias() &&
+      //
+      // TODO: Should this change if we have a Sendable address with a
+      // non-Sendable base.
+      if (destResult.value().value.isNoAlias() &&
+          !resultIsolationInfoOverride &&
           !isProjectedFromAggregate(destValue))
         return translateSILAssign(destValue, src);
 
       // Stores to possibly aliased storage must be treated as merges.
-      return translateSILMerge(destValue, src);
+      return translateSILMerge(destValue, src, /*requireOperand*/true,
+                               resultIsolationInfoOverride);
     }
 
     // Stores to storage of non-Sendable type can be ignored.
@@ -2648,21 +2999,27 @@ class PartitionOpTranslator {
       // specifically in this projection... but that is better than
       // miscompiling. For memory like this, we probably need to track it on a
       // per field basis to allow for us to assign.
-      if (nonSendableTgt.value().isNoAlias() && !isProjectedFromAggregate(dest))
+      //
+      // TODO: Should this change if we have a Sendable address with a
+      // non-Sendable base.
+      if (nonSendableTgt.value().value.isNoAlias() &&
+          !isProjectedFromAggregate(dest))
         return translateSILAssign(
             dest, makeOperandRefRange(inst->getElementOperands()));
 
       // Stores to possibly aliased storage must be treated as merges.
       return translateSILMerge(dest,
-                               makeOperandRefRange(inst->getElementOperands()));
+                               makeOperandRefRange(inst->getElementOperands()),
+                               /*requireOperands=*/true);
     }
 
     // Stores to storage of non-Sendable type can be ignored.
   }
 
   void translateSILRequire(SILValue val) {
-    if (auto nonSendableVal = tryToTrackValue(val))
-      return builder.addRequire(nonSendableVal->getRepresentative().getValue());
+    if (auto lookupResult = tryToTrackValue(val)) {
+      builder.addRequire(*lookupResult);
+    }
   }
 
   /// An enum select is just a multi assign.
@@ -2698,10 +3055,12 @@ class PartitionOpTranslator {
   // and a pointer to the bb being branches to itself.
   // this is handled as assigning to each possible arg being branched to the
   // merge of all values that could be passed to it from this basic block.
-  void translateSILPhi(TermArgSources &argSources) {
+  void translateSILPhi(TermArgSources &argSources,
+                       SILIsolationInfo resultIsolationInfoOverride = {}) {
     argSources.argSources.setFrozen();
     for (auto pair : argSources.argSources.getRange()) {
-      translateSILMultiAssign(TinyPtrVector<SILValue>(pair.first), pair.second);
+      translateSILMultiAssign(TinyPtrVector<SILValue>(pair.first), pair.second,
+                              resultIsolationInfoOverride);
     }
   }
 
@@ -2709,9 +3068,9 @@ class PartitionOpTranslator {
   /// unconditionally and that do not have a result.
   void translateSILSendingNoResult(MutableArrayRef<Operand> values) {
     for (auto &op : values) {
-      if (auto ns = tryToTrackValue(op.get())) {
-        builder.addRequire(ns->getRepresentative().getValue());
-        builder.addSend(ns->getRepresentative().getValue(), &op);
+      if (auto lookupResult = tryToTrackValue(op.get())) {
+        builder.addRequire(*lookupResult);
+        builder.addSend(lookupResult->value, &op);
       }
     }
   }
@@ -2731,13 +3090,13 @@ class PartitionOpTranslator {
         basicBlock->printID(llvm::dbgs()); llvm::dbgs() << SEP_STR;
         basicBlock->print(llvm::dbgs());
         llvm::dbgs() << SEP_STR << "Results:\n";);
+
     // Translate each SIL instruction to the PartitionOps that it represents if
     // any.
+    builder.initialize(foundPartitionOps);
     for (auto &instruction : *basicBlock) {
       REGIONBASEDISOLATION_LOG(llvm::dbgs() << "Visiting: " << instruction);
       translateSILInstruction(&instruction);
-      copy(builder.currentInstPartitionOps,
-           std::back_inserter(foundPartitionOps));
     }
   }
 
@@ -2752,9 +3111,8 @@ class PartitionOpTranslator {
       auto *fArg = cast<SILFunctionArgument>(arg);
       if (fArg->getArgumentConvention().isInoutConvention() &&
           fArg->getKnownParameterInfo().hasOption(SILParameterInfo::Sending)) {
-        if (auto ns = tryToTrackValue(arg)) {
-          auto rep = ns->getRepresentative().getValue();
-          builder.addInOutSendingAtFunctionExit(rep);
+        if (auto lookupResult = tryToTrackValue(arg)) {
+          builder.addInOutSendingAtFunctionExit(lookupResult->value);
         }
       }
     }
@@ -2787,7 +3145,8 @@ class PartitionOpTranslator {
 
     case TranslationSemantics::Assign:
       return translateSILMultiAssign(
-          inst->getResults(), makeOperandRefRange(inst->getAllOperands()));
+          inst->getResults(), makeOperandRefRange(inst->getAllOperands()),
+          SILIsolationInfo::getConformanceIsolation(inst));
 
     case TranslationSemantics::Require:
       for (auto op : inst->getOperandValues())
@@ -2797,8 +3156,6 @@ class PartitionOpTranslator {
     case TranslationSemantics::LookThrough:
       assert(inst->getNumRealOperands() == 1);
       assert((isStaticallyLookThroughInst(inst) ||
-              isLookThroughIfResultNonSendable(inst) ||
-              isLookThroughIfOperandNonSendable(inst) ||
               isLookThroughIfOperandAndResultNonSendable(inst)) &&
              "Out of sync... should return true for one of these categories!");
       return translateSILLookThrough(inst->getResults(), inst->getOperand(0));
@@ -2806,7 +3163,8 @@ class PartitionOpTranslator {
     case TranslationSemantics::Store:
       return translateSILStore(
           &inst->getAllOperands()[CopyLikeInstruction::Dest],
-          &inst->getAllOperands()[CopyLikeInstruction::Src]);
+          &inst->getAllOperands()[CopyLikeInstruction::Src],
+          SILIsolationInfo::getConformanceIsolation(inst));
 
     case TranslationSemantics::Special:
       return;
@@ -2817,7 +3175,8 @@ class PartitionOpTranslator {
     case TranslationSemantics::TerminatorPhi: {
       TermArgSources sources;
       sources.init(inst);
-      return translateSILPhi(sources);
+      return translateSILPhi(
+          sources, SILIsolationInfo::getConformanceIsolation(inst));
     }
 
     case TranslationSemantics::Asserting:
@@ -2860,7 +3219,7 @@ Element PartitionOpBuilder::getActorIntroducingRepresentative(
 
 bool PartitionOpBuilder::valueHasID(SILValue value, bool dumpIfHasNoID) {
   auto v = translator->valueMap.getTrackableValue(value);
-  if (auto m = v.getRepresentative().maybeGetValue())
+  if (auto m = v.value.getRepresentative().maybeGetValue())
     return translator->valueHasID(m, dumpIfHasNoID);
   return true;
 }
@@ -2868,7 +3227,8 @@ bool PartitionOpBuilder::valueHasID(SILValue value, bool dumpIfHasNoID) {
 void PartitionOpBuilder::print(llvm::raw_ostream &os) const {
 #ifndef NDEBUG
   // If we do not have anything to dump, just return.
-  if (currentInstPartitionOps.empty())
+  auto ops = getPartitionOpsForCurrentInst();
+  if (ops.empty())
     return;
 
   // First line.
@@ -2880,8 +3240,6 @@ void PartitionOpBuilder::print(llvm::raw_ostream &os) const {
   currentInst->getLoc().getSourceLoc().printLineAndColumn(
       llvm::dbgs(), currentInst->getFunction()->getASTContext().SourceMgr);
 
-  auto ops = llvm::ArrayRef(currentInstPartitionOps);
-
   // First op on its own line.
   llvm::dbgs() << "\n ├─────╼ ";
   ops.front().print(llvm::dbgs());
@@ -2898,10 +3256,7 @@ void PartitionOpBuilder::print(llvm::raw_ostream &os) const {
   SWIFT_DEFER { opsToPrint.clear(); };
   for (const PartitionOp &op : ops) {
     // Now dump our the root value we map.
-    for (unsigned opArg : op.getOpArgs()) {
-      // If we didn't insert, skip this. We only emit this once.
-      opsToPrint.push_back(Element(opArg));
-    }
+    op.getOpArgs(opsToPrint);
   }
   sortUnique(opsToPrint);
   for (Element opArg : opsToPrint) {
@@ -2909,7 +3264,7 @@ void PartitionOpBuilder::print(llvm::raw_ostream &os) const {
     auto trackableValue = translator->getValueForId(opArg);
     assert(trackableValue);
     llvm::dbgs() << "State: %%" << opArg << ". ";
-    trackableValue->getValueState().print(llvm::dbgs());
+    trackableValue->getValueState().print(getFunction(), llvm::dbgs());
     llvm::dbgs() << "\n             Rep Value: "
                  << trackableValue->getRepresentative();
     if (auto value = trackableValue->getRepresentative().maybeGetValue()) {
@@ -2919,6 +3274,48 @@ void PartitionOpBuilder::print(llvm::raw_ostream &os) const {
 #endif
 }
 
+void PartitionOpBuilder::addRequire(TrackableValue value,
+                                    PartitionOp::Options options) {
+  if (value.isSendable())
+    return;
+  auto silValue = value.getRepresentative().getValue();
+  assert(valueHasID(silValue, /*dumpIfHasNoID=*/true) &&
+         "required value should already have been encountered");
+
+  currentInstPartitionOps->emplace_back(
+      PartitionOp::Require(lookupValueID(silValue), currentInst, options));
+}
+
+void PartitionOpBuilder::addRequire(TrackableValueLookupResult value) {
+  // Call addRequire which will short curcuit if we have a sendable value.
+  addRequire(value.value);
+
+  if (value.value.isSendable()) {
+    auto options = PartitionOp::Options();
+    if (value.base && value.base->isNonSendable()) {
+      // Check if our base was captured by a closure. In such a case, we need to
+      // treat this as a use of the base.
+      auto rep = value.base->getRepresentative().getValue();
+      if (auto boxType = rep->getType().getAs<SILBoxType>()) {
+        // If we are not mutable, we are always safe to access the Sendable
+        // value. The reason why is that we will have copied the non-Sendable
+        // segment by value at +1 when we send it implying that we will
+        if (!boxType->getLayout()->isMutable())
+          return;
+
+        options |= PartitionOp::Flag::RequireOfMutableBaseOfSendableValue;
+      } else if (auto *asi = dyn_cast<AllocStackInst>(rep)) {
+        if (asi->isLet())
+          return;
+
+        options |= PartitionOp::Flag::RequireOfMutableBaseOfSendableValue;
+      }
+
+      addRequire(value.base, options);
+    }
+  }
+}
+
 //===----------------------------------------------------------------------===//
 //                 MARK: Translator - Instruction To Op Kind
 //===----------------------------------------------------------------------===//
@@ -3000,7 +3397,6 @@ CONSTANT_TRANSLATION(TailAddrInst, Assign)
 CONSTANT_TRANSLATION(ThickToObjCMetatypeInst, Assign)
 CONSTANT_TRANSLATION(ThinToThickFunctionInst, Assign)
 CONSTANT_TRANSLATION(UncheckedAddrCastInst, Assign)
-CONSTANT_TRANSLATION(UncheckedEnumDataInst, Assign)
 CONSTANT_TRANSLATION(UncheckedOwnershipConversionInst, Assign)
 CONSTANT_TRANSLATION(IndexRawPointerInst, Assign)
 CONSTANT_TRANSLATION(MarkDependenceAddrInst, Assign)
@@ -3032,6 +3428,7 @@ CONSTANT_TRANSLATION(BridgeObjectToRefInst, LookThrough)
 CONSTANT_TRANSLATION(CopyValueInst, LookThrough)
 CONSTANT_TRANSLATION(ExplicitCopyValueInst, LookThrough)
 CONSTANT_TRANSLATION(EndCOWMutationInst, LookThrough)
+CONSTANT_TRANSLATION(EndCOWMutationAddrInst, Ignored)
 CONSTANT_TRANSLATION(ProjectBoxInst, LookThrough)
 CONSTANT_TRANSLATION(EndInitLetRefInst, LookThrough)
 CONSTANT_TRANSLATION(InitEnumDataAddrInst, LookThrough)
@@ -3062,14 +3459,18 @@ CONSTANT_TRANSLATION(StrongCopyWeakValueInst, LookThrough)
 CONSTANT_TRANSLATION(StrongCopyUnmanagedValueInst, LookThrough)
 CONSTANT_TRANSLATION(RefToUnmanagedInst, LookThrough)
 CONSTANT_TRANSLATION(UnmanagedToRefInst, LookThrough)
-CONSTANT_TRANSLATION(InitExistentialValueInst, LookThrough)
+CONSTANT_TRANSLATION(UncheckedEnumDataInst, LookThrough)
+CONSTANT_TRANSLATION(TupleElementAddrInst, LookThrough)
+CONSTANT_TRANSLATION(StructElementAddrInst, LookThrough)
+CONSTANT_TRANSLATION(VectorBaseAddrInst, LookThrough)
+CONSTANT_TRANSLATION(UncheckedTakeEnumDataAddrInst, LookThrough)
 
 //===---
 // Store
 //
 
 // These are treated as stores - meaning that they could write values into
-// memory. The beahvior of this depends on whether the tgt addr is aliased,
+// memory. The behavior of this depends on whether the tgt addr is aliased,
 // but conservative behavior is to treat these as merges of the regions of
 // the src value and tgt addr
 CONSTANT_TRANSLATION(CopyAddrInst, Store)
@@ -3256,7 +3657,6 @@ CONSTANT_TRANSLATION(DeallocPackMetadataInst, Asserting)
 // All of these instructions should be removed by DI which runs before us in the
 // pass pipeline.
 CONSTANT_TRANSLATION(AssignInst, Asserting)
-CONSTANT_TRANSLATION(AssignByWrapperInst, Asserting)
 CONSTANT_TRANSLATION(AssignOrInitInst, Asserting)
 
 // We should never hit this since it can only appear as a final instruction in a
@@ -3312,9 +3712,6 @@ IGNORE_IF_SENDABLE_RESULT_ASSIGN_OTHERWISE(StructExtractInst)
 LOOKTHROUGH_IF_NONSENDABLE_RESULT_AND_OPERAND(UncheckedTrivialBitCastInst)
 LOOKTHROUGH_IF_NONSENDABLE_RESULT_AND_OPERAND(UncheckedBitwiseCastInst)
 LOOKTHROUGH_IF_NONSENDABLE_RESULT_AND_OPERAND(UncheckedValueCastInst)
-LOOKTHROUGH_IF_NONSENDABLE_RESULT_AND_OPERAND(TupleElementAddrInst)
-LOOKTHROUGH_IF_NONSENDABLE_RESULT_AND_OPERAND(StructElementAddrInst)
-LOOKTHROUGH_IF_NONSENDABLE_RESULT_AND_OPERAND(UncheckedTakeEnumDataAddrInst)
 LOOKTHROUGH_IF_NONSENDABLE_RESULT_AND_OPERAND(ConvertEscapeToNoEscapeInst)
 LOOKTHROUGH_IF_NONSENDABLE_RESULT_AND_OPERAND(ConvertFunctionInst)
 
@@ -3335,7 +3732,7 @@ PartitionOpTranslator::visitStoreBorrowInst(StoreBorrowInst *sbi) {
   SILValue destValue = sbi->getDest();
 
   auto nonSendableDest = tryToTrackValue(destValue);
-  if (!nonSendableDest)
+  if (!nonSendableDest || nonSendableDest->value.isSendable())
     return TranslationSemantics::Ignored;
 
   // In the following situations, we can perform an assign:
@@ -3349,7 +3746,7 @@ PartitionOpTranslator::visitStoreBorrowInst(StoreBorrowInst *sbi) {
   // specifically in this projection... but that is better than
   // miscompiling. For memory like this, we probably need to track it on a
   // per field basis to allow for us to assign.
-  if (nonSendableDest.value().isNoAlias() &&
+  if (nonSendableDest.value().value.isNoAlias() &&
       !isProjectedFromAggregate(destValue)) {
     translateSILMultiAssign(sbi->getResults(),
                             makeOperandRefRange(sbi->getAllOperands()),
@@ -3409,20 +3806,42 @@ PartitionOpTranslator::visitBeginBorrowInst(BeginBorrowInst *bbi) {
   return TranslationSemantics::LookThrough;
 }
 
-/// LoadInst is technically a statically look through instruction, but we want
-/// to handle it especially in the infrastructure, so we cannot mark it as
-/// such. This makes marking it as a normal lookthrough instruction impossible
-/// since the routine checks that invariant.
-TranslationSemantics PartitionOpTranslator::visitLoadInst(LoadInst *limvi) {
+/// LoadInst has two different semantics:
+///
+/// 1. If the load produces a non-Sendable value, we want to treat it as a
+/// statically look through instruction, but we want to handle it especially in
+/// the infrastructure, so we cannot mark it as such. This makes marking it as a
+/// normal lookthrough instruction impossible since the routine checks that
+/// invariant.
+///
+/// 2. If the load produces a Sendable value, we want to perform a require on
+/// the address so that if we have a load from a non-Sendable base, we properly
+/// require the base.
+TranslationSemantics PartitionOpTranslator::visitLoadInst(LoadInst *li) {
+  if (SILIsolationInfo::isSendableType(li->getOperand())) {
+    translateSILRequire(li->getOperand());
+  }
+
   return TranslationSemantics::Special;
 }
 
-/// LoadBorrowInst is technically a statically look through instruction, but we
-/// want to handle it especially in the infrastructure, so we cannot mark it as
-/// such. This makes marking it as a normal lookthrough instruction impossible
-/// since the routine checks that invariant.
+/// LoadBorrowInst has two different semantics:
+///
+/// 1. If the load produces a non-Sendable value, we want to treat it as a
+/// statically look through instruction, but we want to handle it especially in
+/// the infrastructure, so we cannot mark it as such. This makes marking it as a
+/// normal lookthrough instruction impossible since the routine checks that
+/// invariant.
+///
+/// 2. If the load produces a Sendable value, we want to perform a require on
+/// the address so that if we have a load from a non-Sendable base, we properly
+/// require the base.
 TranslationSemantics
 PartitionOpTranslator::visitLoadBorrowInst(LoadBorrowInst *lbi) {
+  if (SILIsolationInfo::isSendableType(lbi->getOperand())) {
+    translateSILRequire(lbi->getOperand());
+  }
+
   return TranslationSemantics::Special;
 }
 
@@ -3483,8 +3902,11 @@ PartitionOpTranslator::visitPackElementSetInst(PackElementSetInst *r) {
 
 TranslationSemantics
 PartitionOpTranslator::visitRawPointerToRefInst(RawPointerToRefInst *r) {
-  assert(isLookThroughIfResultNonSendable(r) && "Out of sync");
+  assert(isLookThroughIfOperandAndResultNonSendable(r) && "Out of sync");
   // If our result is non sendable, perform a look through.
+  //
+  // NOTE: From RBI perspective, RawPointer is non-Sendable, so this is really
+  // just look through if operand and result non-Sendable.
   if (isNonSendableType(r->getType()))
     return TranslationSemantics::LookThrough;
 
@@ -3494,9 +3916,12 @@ PartitionOpTranslator::visitRawPointerToRefInst(RawPointerToRefInst *r) {
 
 TranslationSemantics
 PartitionOpTranslator::visitRefToRawPointerInst(RefToRawPointerInst *r) {
-  assert(isLookThroughIfOperandNonSendable(r) && "Out of sync");
+  assert(isLookThroughIfOperandAndResultNonSendable(r) && "Out of sync");
 
   // If our source ref is non sendable, perform a look through.
+  //
+  // NOTE: From RBI perspective, RawPointer is non-Sendable, so this is really
+  // just look through if operand and result non-Sendable.
   if (isNonSendableType(r->getOperand()->getType()))
     return TranslationSemantics::LookThrough;
 
@@ -3530,7 +3955,10 @@ PartitionOpTranslator::visitPointerToAddressInst(PointerToAddressInst *ptai) {
 
 TranslationSemantics PartitionOpTranslator::visitUnconditionalCheckedCastInst(
     UnconditionalCheckedCastInst *ucci) {
-  if (SILDynamicCastInst(ucci).isRCIdentityPreserving()) {
+  auto isolation = SILIsolationInfo::getConformanceIsolation(ucci);
+
+  if (!isolation &&
+      SILDynamicCastInst(ucci).isRCIdentityPreserving()) {
     assert(isStaticallyLookThroughInst(ucci) && "Out of sync");
     return TranslationSemantics::LookThrough;
   }
@@ -3625,6 +4053,14 @@ PartitionOpTranslator::visitPartialApplyInst(PartialApplyInst *pai) {
   return TranslationSemantics::Special;
 }
 
+TranslationSemantics
+PartitionOpTranslator::visitInitExistentialValueInst(InitExistentialValueInst *ievi) {
+  if (isStaticallyLookThroughInst(ievi))
+    return TranslationSemantics::LookThrough;
+
+  return TranslationSemantics::Assign;
+}
+
 TranslationSemantics PartitionOpTranslator::visitCheckedCastAddrBranchInst(
     CheckedCastAddrBranchInst *ccabi) {
   assert(ccabi->getSuccessBB()->getNumArguments() <= 1);
@@ -3637,7 +4073,8 @@ TranslationSemantics PartitionOpTranslator::visitCheckedCastAddrBranchInst(
   // is. For now just keep the current behavior. It is more conservative,
   // but still correct.
   translateSILMultiAssign(ArrayRef<SILValue>(),
-                          makeOperandRefRange(ccabi->getAllOperands()));
+                          makeOperandRefRange(ccabi->getAllOperands()),
+                          SILIsolationInfo::getConformanceIsolation(ccabi));
   return TranslationSemantics::Special;
 }
 
@@ -3677,13 +4114,16 @@ bool BlockPartitionState::recomputeExitFromEntry(
     }
 
     std::optional<Element> getElement(SILValue value) const {
-      return translator.getValueMap().getTrackableValue(value).getID();
+      auto trackableValue = translator.getValueMap().getTrackableValue(value);
+      if (trackableValue.value.isSendable())
+        return {};
+      return trackableValue.value.getID();
     }
 
     SILValue getRepresentative(SILValue value) const {
       return translator.getValueMap()
           .getTrackableValue(value)
-          .getRepresentative()
+          .value.getRepresentative()
           .maybeGetValue();
     }
 
@@ -3802,7 +4242,7 @@ RegionAnalysisFunctionInfo::RegionAnalysisFunctionInfo(
   }
   // Set our entry partition to have the "entry partition".
   (*blockStates)[fn->getEntryBlock()].entryPartition =
-      translator->getEntryPartition();
+      translator->getInitialEntryPartition();
   runDataflow();
 }
 
@@ -3898,3 +4338,25 @@ void RegionAnalysis::initialize(SILPassManager *pm) {
 SILAnalysis *swift::createRegionAnalysis(SILModule *) {
   return new RegionAnalysis();
 }
+
+//===----------------------------------------------------------------------===//
+//                                MARK: Tests
+//===----------------------------------------------------------------------===//
+
+namespace swift::test {
+
+// Arguments:
+// - SILValue: value to look up isolation for.
+// Dumps:
+// - The inferred isolation.
+static FunctionTest
+    UnderlyingTrackedValue("sil_regionanalysis_underlying_tracked_value",
+                            [](auto &function, auto &arguments, auto &test) {
+                              RegionAnalysisValueMap valueMap(&function);
+                              auto value = arguments.takeValue();
+                              auto trackableValue = valueMap.getTrackableValue(value);
+                              trackableValue.print(&function, llvm::outs());
+                              llvm::outs() << '\n';
+                            });
+
+} // namespace swift::test
diff --git a/lib/SILOptimizer/Analysis/SimplifyInstruction.cpp b/lib/SILOptimizer/Analysis/SimplifyInstruction.cpp
index e5881fb9f2895..ca8b1b7a501ff 100644
--- a/lib/SILOptimizer/Analysis/SimplifyInstruction.cpp
+++ b/lib/SILOptimizer/Analysis/SimplifyInstruction.cpp
@@ -52,7 +52,6 @@ namespace {
     SILValue
     visitUnconditionalCheckedCastInst(UnconditionalCheckedCastInst *UCCI);
     SILValue visitUncheckedRefCastInst(UncheckedRefCastInst *OPRI);
-    SILValue visitUncheckedAddrCastInst(UncheckedAddrCastInst *UACI);
     SILValue visitStructInst(StructInst *SI);
     SILValue visitTupleInst(TupleInst *SI);
     SILValue visitBuiltinInst(BuiltinInst *AI);
@@ -357,21 +356,6 @@ visitUncheckedRefCastInst(UncheckedRefCastInst *OPRI) {
   return simplifyDeadCast(OPRI);
 }
 
-SILValue
-InstSimplifier::
-visitUncheckedAddrCastInst(UncheckedAddrCastInst *UACI) {
-  // (unchecked-addr-cast Y->X (unchecked-addr-cast x X->Y)) -> x
-  if (auto *OtherUACI = dyn_cast<UncheckedAddrCastInst>(&*UACI->getOperand()))
-    if (OtherUACI->getOperand()->getType() == UACI->getType())
-      return OtherUACI->getOperand();
-
-  // (unchecked-addr-cast X->X x) -> x
-  if (UACI->getOperand()->getType() == UACI->getType())
-    return UACI->getOperand();
-
-  return SILValue();
-}
-
 SILValue InstSimplifier::visitUpcastInst(UpcastInst *UI) {
   // (upcast Y->X (unchecked-ref-cast x X->Y)) -> x
   if (auto *URCI = dyn_cast<UncheckedRefCastInst>(UI->getOperand()))
diff --git a/lib/SILOptimizer/Differentiation/ADContext.cpp b/lib/SILOptimizer/Differentiation/ADContext.cpp
index b28acdb3ccb86..3141c5b0649c0 100644
--- a/lib/SILOptimizer/Differentiation/ADContext.cpp
+++ b/lib/SILOptimizer/Differentiation/ADContext.cpp
@@ -62,10 +62,8 @@ ADContext::ADContext(SILModuleTransform &transform)
 
 /// Get the source file for the given `SILFunction`.
 static SourceFile &getSourceFile(SILFunction *f) {
-  if (f->hasLocation())
-    if (auto *declContext = f->getLocation().getAsDeclContext())
-      if (auto *parentSourceFile = declContext->getParentSourceFile())
-        return *parentSourceFile;
+  if (SourceFile *file = f->getSourceFile())
+    return *file;
   for (auto *file : f->getModule().getSwiftModule()->getFiles())
     if (auto *sourceFile = dyn_cast<SourceFile>(file))
       return *sourceFile;
diff --git a/lib/SILOptimizer/Differentiation/Common.cpp b/lib/SILOptimizer/Differentiation/Common.cpp
index ee92aad8894dc..6fb6b07332056 100644
--- a/lib/SILOptimizer/Differentiation/Common.cpp
+++ b/lib/SILOptimizer/Differentiation/Common.cpp
@@ -61,10 +61,10 @@ bool isSemanticMemberAccessor(SILFunction *original) {
   auto *accessor = dyn_cast<AccessorDecl>(decl);
   if (!accessor)
     return false;
-  // Currently, only getters and setters are supported.
-  // TODO(https://github.com/apple/swift/issues/55084): Support `modify` accessors.
+  // Currently, only getters, setters and _modify accessors are supported.
   if (accessor->getAccessorKind() != AccessorKind::Get &&
-      accessor->getAccessorKind() != AccessorKind::Set)
+      accessor->getAccessorKind() != AccessorKind::Set &&
+      accessor->getAccessorKind() != AccessorKind::Modify)
     return false;
   // Accessor must come from a `var` declaration.
   auto *varDecl = dyn_cast<VarDecl>(accessor->getStorage());
@@ -538,9 +538,14 @@ SILDifferentiabilityWitness *getOrCreateMinimalASTDifferentiabilityWitness(
          "definitions with explicit differentiable attributes");
 
   return SILDifferentiabilityWitness::createDeclaration(
-      module, SILLinkage::PublicExternal, original, kind,
-      minimalConfig->parameterIndices, minimalConfig->resultIndices,
-      minimalConfig->derivativeGenericSignature);
+      module,
+      // Witness for @_alwaysEmitIntoClient original function must be emitted,
+      // otherwise a linker error would occur due to undefined reference to the
+      // witness symbol.
+      original->markedAsAlwaysEmitIntoClient() ? SILLinkage::PublicNonABI
+                                               : SILLinkage::PublicExternal,
+      original, kind, minimalConfig->parameterIndices,
+      minimalConfig->resultIndices, minimalConfig->derivativeGenericSignature);
 }
 
 } // end namespace autodiff
diff --git a/lib/SILOptimizer/Differentiation/JVPCloner.cpp b/lib/SILOptimizer/Differentiation/JVPCloner.cpp
index d7c3fa636429e..588ec85227886 100644
--- a/lib/SILOptimizer/Differentiation/JVPCloner.cpp
+++ b/lib/SILOptimizer/Differentiation/JVPCloner.cpp
@@ -42,7 +42,7 @@ namespace swift {
 namespace autodiff {
 
 class JVPCloner::Implementation final
-    : public TypeSubstCloner<JVPCloner::Implementation, SILOptFunctionBuilder> {
+    : public TypeSubstCloner<JVPCloner::Implementation> {
 private:
   /// The global context.
   ADContext &context;
@@ -949,7 +949,7 @@ class JVPCloner::Implementation final
     auto tanDest = getTangentBuffer(bb, uccai->getDest());
 
     diffBuilder.createUnconditionalCheckedCastAddr(
-       loc, uccai->getIsolatedConformances(),
+       loc, uccai->getCheckedCastOptions(),
         tanSrc, tanSrc->getType().getASTType(),
         tanDest, tanDest->getType().getASTType());
   }
diff --git a/lib/SILOptimizer/Differentiation/PullbackCloner.cpp b/lib/SILOptimizer/Differentiation/PullbackCloner.cpp
index ea70fe42e65dc..02be267e1d6fc 100644
--- a/lib/SILOptimizer/Differentiation/PullbackCloner.cpp
+++ b/lib/SILOptimizer/Differentiation/PullbackCloner.cpp
@@ -905,6 +905,7 @@ class PullbackCloner::Implementation final
   bool runForSemanticMemberAccessor();
   bool runForSemanticMemberGetter();
   bool runForSemanticMemberSetter();
+  bool runForSemanticMemberModify();
 
   /// If original result is non-varied, it will always have a zero derivative.
   /// Skip full pullback generation and simply emit zero derivatives for wrt
@@ -1780,8 +1781,12 @@ class PullbackCloner::Implementation final
   void visitMoveValueInst(MoveValueInst *mvi) {
     switch (getTangentValueCategory(mvi)) {
     case SILValueCategory::Address:
-      llvm::report_fatal_error("AutoDiff does not support move_value with "
-                               "SILValueCategory::Address");
+      LLVM_DEBUG(getADDebugStream() << "AutoDiff does not support move_value with "
+                 "SILValueCategory::Address");
+      getContext().emitNondifferentiabilityError(
+        mvi, getInvoker(), diag::autodiff_expression_not_differentiable_note);
+      errorOccurred = true;
+      return;
     case SILValueCategory::Object:
       visitValueOwnershipInst(mvi, /*needZeroResAdj=*/true);
     }
@@ -1822,7 +1827,7 @@ class PullbackCloner::Implementation final
     auto adjSrc = getAdjointBuffer(bb, uccai->getSrc());
     auto castBuf = builder.createAllocStack(uccai->getLoc(), adjSrc->getType());
     builder.createUnconditionalCheckedCastAddr(
-        uccai->getLoc(), uccai->getIsolatedConformances(),
+        uccai->getLoc(), uccai->getCheckedCastOptions(),
         adjDest, adjDest->getType().getASTType(), castBuf,
         adjSrc->getType().getASTType());
     addToAdjointBuffer(bb, uccai->getSrc(), castBuf, uccai->getLoc());
@@ -2095,6 +2100,23 @@ PullbackCloner::PullbackCloner(VJPCloner &vjpCloner)
 
 PullbackCloner::~PullbackCloner() { delete &impl; }
 
+static SILValue getArrayValue(ApplyInst *ai) {
+  SILValue arrayValue;
+  for (auto use : ai->getUses()) {
+    auto *dti = dyn_cast<DestructureTupleInst>(use->getUser());
+    if (!dti)
+      continue;
+    DEBUG_ASSERT(!arrayValue && "Array value already found");
+    // The first `destructure_tuple` result is the `Array` value.
+    arrayValue = dti->getResult(0);
+#ifndef DEBUG_ASSERT_enabled
+    break;
+#endif
+  }
+  ASSERT(arrayValue);
+  return arrayValue;
+}
+
 //--------------------------------------------------------------------------//
 // Entry point
 //--------------------------------------------------------------------------//
@@ -2431,7 +2453,8 @@ bool PullbackCloner::Implementation::run() {
 
   // If the original function is an accessor with special-case pullback
   // generation logic, do special-case generation.
-  if (isSemanticMemberAccessor(&original)) {
+  bool isSemanticMemberAcc = isSemanticMemberAccessor(&original);
+  if (isSemanticMemberAcc) {
     if (runForSemanticMemberAccessor())
       return true;
   }
@@ -2439,6 +2462,134 @@ bool PullbackCloner::Implementation::run() {
   // Visit original blocks in post-order and perform differentiation
   // in corresponding pullback blocks. If errors occurred, back out.
   else {
+    LLVM_DEBUG(getADDebugStream()
+               << "Begin search for adjoints of loop-local active values\n");
+    llvm::DenseMap<const SILLoop *, llvm::DenseSet<SILValue>>
+        loopLocalActiveValues;
+    for (auto *bb : originalBlocks) {
+      const SILLoop *loop = vjpCloner.getLoopInfo()->getLoopFor(bb);
+      if (loop == nullptr)
+        continue;
+      SILBasicBlock *loopHeader = loop->getHeader();
+      SILBasicBlock *pbLoopHeader = getPullbackBlock(loopHeader);
+      LLVM_DEBUG(getADDebugStream()
+                 << "Original bb" << bb->getDebugID()
+                 << " belongs to a loop, original header bb"
+                 << loopHeader->getDebugID() << ", pullback header bb"
+                 << pbLoopHeader->getDebugID() << '\n');
+      builder.setInsertionPoint(pbLoopHeader);
+      auto bbActiveValuesIt = activeValues.find(bb);
+      if (bbActiveValuesIt == activeValues.end())
+        continue;
+      const auto &bbActiveValues = bbActiveValuesIt->second;
+      for (SILValue bbActiveValue : bbActiveValues) {
+        if (vjpCloner.getLoopInfo()->getLoopFor(
+                bbActiveValue->getParentBlock()) != loop) {
+          LLVM_DEBUG(
+              getADDebugStream()
+              << "The following active value is NOT loop-local, skipping: "
+              << bbActiveValue);
+          continue;
+        }
+
+        auto [_, wasInserted] =
+            loopLocalActiveValues[loop].insert(bbActiveValue);
+        LLVM_DEBUG(getADDebugStream()
+                   << "The following active value is loop-local, ");
+        if (!wasInserted) {
+          LLVM_DEBUG(llvm::dbgs() << "but it was already processed, skipping: "
+                                  << bbActiveValue);
+          continue;
+        }
+
+        if (getTangentValueCategory(bbActiveValue) ==
+            SILValueCategory::Object) {
+          LLVM_DEBUG(llvm::dbgs()
+                     << "zeroing its adjoint value in loop header: "
+                     << bbActiveValue);
+          setAdjointValue(bb, bbActiveValue,
+                          makeZeroAdjointValue(getRemappedTangentType(
+                              bbActiveValue->getType())));
+          continue;
+        }
+
+        ASSERT(getTangentValueCategory(bbActiveValue) ==
+               SILValueCategory::Address);
+
+        // getAdjointProjection might call materializeAdjointDirect which
+        // writes to debug output, emit \n.
+        LLVM_DEBUG(llvm::dbgs()
+                   << "checking if it's adjoint is a projection\n");
+
+        if (!getAdjointProjection(bb, bbActiveValue)) {
+          LLVM_DEBUG(getADDebugStream()
+                     << "Adjoint for the following value is NOT a projection, "
+                        "zeroing its adjoint buffer in loop header: "
+                     << bbActiveValue);
+
+          // All adjoint buffers are allocated in the pullback entry and
+          // deallocated in the pullback exit. So, use IsNotInitialization to
+          // emit destroy_addr before zeroing the buffer.
+          ASSERT(bufferMap.contains({bb, bbActiveValue}));
+          builder.emitZeroIntoBuffer(pbLoc, getAdjointBuffer(bb, bbActiveValue),
+                                     IsNotInitialization);
+
+          continue;
+        }
+
+        LLVM_DEBUG(getADDebugStream()
+                   << "Adjoint for the following value is a projection, ");
+
+        // If Projection::isAddressProjection(v) is true for a value v, it
+        // is not added to active values list (see recordValueIfActive).
+        //
+        // Ensure that only the following value types conforming to
+        // getAdjointProjection but not conforming to
+        // Projection::isAddressProjection can go here.
+        //
+        // Instructions conforming to Projection::isAddressProjection and
+        // thus never corresponding to an active value do not need any
+        // handling, because only active values can have adjoints from
+        // previous iterations propagated via BB arguments.
+        do {
+          // Consider '%X = begin_access [modify] [static] %Y'.
+          // 1. If %Y is loop-local, it's adjoint buffer will
+          //    be zeroed, and we'll have zero adjoint projection to it.
+          // 2. Otherwise, we do not need to zero the projection buffer.
+          // Thus, we can just skip.
+          if (dyn_cast<BeginAccessInst>(bbActiveValue)) {
+            LLVM_DEBUG(llvm::dbgs() << "skipping: " << bbActiveValue);
+            break;
+          }
+
+          // Consider the following sequence:
+          //   %1 = function_ref @allocUninitArray
+          //   %2 = apply %1<Float>(%0)
+          //   (%3, %4) = destructure_tuple %2
+          //   %5 = mark_dependence %4 on %3
+          //   %6 = pointer_to_address %6 to [strict] $*Float
+          // Since %6 is active, %3 (which is an array) must also be active.
+          // Thus, adjoint for %3 will be zeroed if needed. Ensure that expected
+          // invariants hold and then skip.
+          if (auto *ai = getAllocateUninitializedArrayIntrinsicElementAddress(
+                  bbActiveValue)) {
+            ASSERT(isa<PointerToAddressInst>(bbActiveValue));
+            SILValue arrayValue = getArrayValue(ai);
+            ASSERT(llvm::find(bbActiveValues, arrayValue) !=
+                   bbActiveValues.end());
+            ASSERT(vjpCloner.getLoopInfo()->getLoopFor(
+                       arrayValue->getParentBlock()) == loop);
+            LLVM_DEBUG(llvm::dbgs() << "skipping: " << bbActiveValue);
+            break;
+          }
+
+          ASSERT(false);
+        } while (false);
+      }
+    }
+    LLVM_DEBUG(getADDebugStream()
+               << "End search for adjoints of loop-local active values\n");
+
     for (auto *bb : originalBlocks) {
       visitSILBasicBlock(bb);
       if (errorOccurred)
@@ -2581,7 +2732,8 @@ bool PullbackCloner::Implementation::run() {
 #endif
 
   LLVM_DEBUG(getADDebugStream()
-             << "Generated pullback for " << original.getName() << ":\n"
+             << "Generated " << (isSemanticMemberAcc ? "semantic member accessor" : "normal")
+             << " pullback for " << original.getName() << ":\n"
              << pullback);
   return errorOccurred;
 }
@@ -2976,8 +3128,21 @@ void PullbackCloner::Implementation::visitSILBasicBlock(SILBasicBlock *bb) {
         break;
       }
       }
-    } else
-      llvm::report_fatal_error("do not know how to handle this incoming bb argument");
+    } else {
+      LLVM_DEBUG(getADDebugStream() <<
+                 "do not know how to handle this incoming bb argument");
+      if (auto term = bbArg->getSingleTerminator()) {
+        getContext().emitNondifferentiabilityError(term, getInvoker(),
+          diag::autodiff_expression_not_differentiable_note);
+      } else {
+        // This will be a bit confusing, but still better than nothing.
+        getContext().emitNondifferentiabilityError(bbArg, getInvoker(),
+          diag::autodiff_expression_not_differentiable_note);
+      }
+
+      errorOccurred = true;
+      return;
+    }
   }
 
   // 3. Build the pullback successor cases for the `switch_enum`
@@ -3043,7 +3208,8 @@ bool PullbackCloner::Implementation::runForSemanticMemberAccessor() {
     return runForSemanticMemberGetter();
   case AccessorKind::Set:
     return runForSemanticMemberSetter();
-  // TODO(https://github.com/apple/swift/issues/55084): Support `modify` accessors.
+  case AccessorKind::Modify:
+    return runForSemanticMemberModify();
   default:
     llvm_unreachable("Unsupported accessor kind; inconsistent with "
                      "`isSemanticMemberAccessor`?");
@@ -3227,6 +3393,83 @@ bool PullbackCloner::Implementation::runForSemanticMemberSetter() {
   return false;
 }
 
+bool PullbackCloner::Implementation::runForSemanticMemberModify() {
+  auto &original = getOriginal();
+  auto &pullback = getPullback();
+  auto pbLoc = getPullback().getLocation();
+
+  auto *accessor = cast<AccessorDecl>(original.getDeclContext()->getAsDecl());
+  assert(accessor->getAccessorKind() == AccessorKind::Modify);
+
+  auto *origEntry = original.getEntryBlock();
+  // We assume that the accessor has a simple 3-BB structure with yield in the entry BB
+  // plus resume and unwind BBs
+  auto *yi = cast<YieldInst>(origEntry->getTerminator());
+  auto *origResumeBB = yi->getResumeBB();
+
+  auto *pbEntry = pullback.getEntryBlock();
+  builder.setCurrentDebugScope(
+      remapScope(origEntry->getScopeOfFirstNonMetaInstruction()));
+  builder.setInsertionPoint(pbEntry);
+
+  // Get _modify accessor argument values.
+  // Accessor type : $(inout Self) -> @yields @inout Argument
+  // Pullback type : $(inout Self', linear map tuple) -> @yields @inout Argument'
+  // Normally pullbacks for semantic member accessors are single BB and
+  // therefore have empty linear map tuple, however, coroutines have a branching
+  // control flow due to possible coroutine abort, so we need to accommodate for
+  // this. We keep branch tracing enums in order not to special case in many
+  // other places. As there is no way to return to coroutine via abort exit, we
+  // essentially "linearize" a coroutine.
+  auto loweredFnTy = original.getLoweredFunctionType();
+  auto pullbackLoweredFnTy = pullback.getLoweredFunctionType();
+
+  assert(loweredFnTy->getNumParameters() == 1 &&
+         loweredFnTy->getNumYields() == 1);
+  assert(pullbackLoweredFnTy->getNumParameters() == 2);
+  assert(pullbackLoweredFnTy->getNumYields() == 1);
+
+  SILValue origSelf = original.getArgumentsWithoutIndirectResults().front();
+
+  SmallVector<SILValue, 8> origFormalResults;
+  collectAllFormalResultsInTypeOrder(original, origFormalResults);
+
+  assert(getConfig().resultIndices->getNumIndices() == 2 &&
+         "Modify accessor should have two semantic results");
+
+  auto origYield = origFormalResults[*std::next(getConfig().resultIndices->begin())];
+
+  // Look up the corresponding field in the tangent space.
+  auto *origField = cast<VarDecl>(accessor->getStorage());
+  auto baseType = remapType(origSelf->getType()).getASTType();
+  auto *tanField = getTangentStoredProperty(getContext(), origField, baseType,
+                                            pbLoc, getInvoker());
+  if (!tanField) {
+    errorOccurred = true;
+    return true;
+  }
+
+  auto adjSelf = getAdjointBuffer(origResumeBB, origSelf);
+  auto *adjSelfElt = builder.createStructElementAddr(pbLoc, adjSelf, tanField);
+  // Modify accessors have inout yields and therefore should yield addresses.
+  assert(getTangentValueCategory(origYield) == SILValueCategory::Address &&
+         "Modify accessors should yield indirect");
+
+  // Yield the adjoint buffer and do everything else in the resume
+  // destination. Unwind destination is unreachable as the coroutine can never
+  // be aborted.
+  auto *unwindBB = getPullback().createBasicBlock();
+  auto *resumeBB = getPullbackBlock(origEntry);
+  builder.createYield(yi->getLoc(), {adjSelfElt}, resumeBB, unwindBB);
+  builder.setInsertionPoint(unwindBB);
+  builder.createUnreachable(SILLocation::invalid());
+
+  builder.setInsertionPoint(resumeBB);
+  addToAdjointBuffer(origEntry, origSelf, adjSelf, pbLoc);
+
+  return false;
+}
+
 //--------------------------------------------------------------------------//
 // Adjoint buffer mapping
 //--------------------------------------------------------------------------//
@@ -3339,19 +3582,9 @@ SILValue PullbackCloner::Implementation::getAdjointProjection(
       eltIndex = ili->getValue().getLimitedValue();
     }
     // Get the array adjoint value.
-    SILValue arrayAdjoint;
-    assert(ai && "Expected `array.uninitialized_intrinsic` application");
-    for (auto use : ai->getUses()) {
-      auto *dti = dyn_cast<DestructureTupleInst>(use->getUser());
-      if (!dti)
-        continue;
-      assert(!arrayAdjoint && "Array adjoint already found");
-      // The first `destructure_tuple` result is the `Array` value.
-      auto arrayValue = dti->getResult(0);
-      arrayAdjoint = materializeAdjointDirect(
-          getAdjointValue(origBB, arrayValue), definingInst->getLoc());
-    }
-    assert(arrayAdjoint && "Array does not have adjoint value");
+    SILValue arrayValue = getArrayValue(ai);
+    SILValue arrayAdjoint = materializeAdjointDirect(
+        getAdjointValue(origBB, arrayValue), definingInst->getLoc());
     // Apply `Array.TangentVector.subscript` to get array element adjoint value.
     auto *eltAdjBuffer =
         getArrayAdjointElementBuffer(arrayAdjoint, eltIndex, ai->getLoc());
@@ -3514,14 +3747,31 @@ void PullbackCloner::Implementation::
   if (originalValue != dti->getResult(0))
     return;
   // Accumulate the array's adjoint value into the adjoint buffers of its
-  // element addresses: `pointer_to_address` and `index_addr` instructions.
+  // element addresses: `pointer_to_address` and (optionally) `index_addr`
+  // instructions.
+  // The input code looks like as follows:
+  //  %17 = integer_literal $Builtin.Word, 1
+  //  function_ref _allocateUninitializedArray<A>(_:)
+  //  %18 = function_ref @$ss27_allocateUninitializedArrayySayxG_BptBwlF : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
+  //  %19 = apply %18<Float>(%17) : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
+  //  (%20, %21) = destructure_tuple %19
+  //  %22 = mark_dependence %21 on %20
+  //  %23 = pointer_to_address %22 to [strict] $*Float
+  //  store %0 to [trivial] %23
+  //  function_ref _finalizeUninitializedArray<A>(_:)
+  //  %25 = function_ref @$ss27_finalizeUninitializedArrayySayxGABnlF : $@convention(thin) <τ_0_0> (@owned Array<τ_0_0>) -> @owned Array<τ_0_0>
+  //  %26 = apply %25<Float>(%20) : $@convention(thin) <τ_0_0> (@owned Array<τ_0_0>) -> @owned Array<τ_0_0> // user: %27
+  // Note that %20 and %21 are in some sense "aliases" for each other. Here our `originalValue` is %20 in the code above.
+  // We need to trace from %21 down to %23 and propagate (decomposed) adjoint of originalValue to adjoint of %23.
+  // Then the generic adjoint propagation code would do its job to propagate %23' to %0'.
+  // If we're initializing multiple values we're having additional `index_addr` instructions, but
+  // the handling is similar.
   LLVM_DEBUG(getADDebugStream()
              << "Accumulating adjoint value for array literal into element "
                 "address adjoint buffers"
              << originalValue);
   auto arrayAdjoint = materializeAdjointDirect(arrayAdjointValue, loc);
   builder.setCurrentDebugScope(remapScope(dti->getDebugScope()));
-  builder.setInsertionPoint(arrayAdjoint->getParentBlock());
   for (auto use : dti->getResult(1)->getUses()) {
     auto *mdi = dyn_cast<MarkDependenceInst>(use->getUser());
     assert(mdi && "Expected mark_dependence user");
diff --git a/lib/SILOptimizer/Differentiation/Thunk.cpp b/lib/SILOptimizer/Differentiation/Thunk.cpp
index e4328547d90d3..8081616571d9b 100644
--- a/lib/SILOptimizer/Differentiation/Thunk.cpp
+++ b/lib/SILOptimizer/Differentiation/Thunk.cpp
@@ -621,22 +621,33 @@ getOrCreateSubsetParametersThunkForLinearMap(
 
   // If differential thunk, deallocate local allocations and directly return
   // `apply` result (if it is desired).
+  // TODO: Unify with VJP code below
   if (kind == AutoDiffDerivativeFunctionKind::JVP) {
     SmallVector<SILValue, 8> differentialDirectResults;
     extractAllElements(ai, builder, differentialDirectResults);
     SmallVector<SILValue, 8> allResults;
     collectAllActualResultsInTypeOrder(ai, differentialDirectResults, allResults);
-    unsigned numResults = thunk->getConventions().getNumDirectSILResults() +
-     thunk->getConventions().getNumDirectSILResults();
     SmallVector<SILValue, 8> results;
-    for (unsigned idx : *actualConfig.resultIndices) {
-      if (idx >= numResults)
-        break;
 
-      auto result = allResults[idx];
-      if (desiredConfig.isWrtResult(idx))
-        results.push_back(result);
-      else {
+    unsigned firstSemanticParamResultIdx = origFnType->getNumResults();
+    for (unsigned resultIndex : *actualConfig.resultIndices) {
+      SILValue result;
+      if (resultIndex >= firstSemanticParamResultIdx) {
+        auto semanticResultArgIdx = resultIndex - firstSemanticParamResultIdx;
+        result =
+          *std::next(ai->getAutoDiffSemanticResultArguments().begin(),
+                     semanticResultArgIdx);
+      } else
+        result = allResults[resultIndex];
+
+      // If result is desired:
+      // - Do nothing if result is indirect.
+      //   (It was already forwarded to the `apply` instruction).
+      // - Push it to `results` if result is direct.
+      if (desiredConfig.isWrtResult(resultIndex)) {
+        if (result->getType().isObject())
+          results.push_back(result);
+      } else { // Otherwise, cleanup the unused results.
         if (result->getType().isAddress())
           builder.emitDestroyAddrAndFold(loc, result);
         else
diff --git a/lib/SILOptimizer/Differentiation/VJPCloner.cpp b/lib/SILOptimizer/Differentiation/VJPCloner.cpp
index eb2377fc308c9..f04389af3d9a4 100644
--- a/lib/SILOptimizer/Differentiation/VJPCloner.cpp
+++ b/lib/SILOptimizer/Differentiation/VJPCloner.cpp
@@ -41,7 +41,7 @@ namespace swift {
 namespace autodiff {
 
 class VJPCloner::Implementation final
-    : public TypeSubstCloner<VJPCloner::Implementation, SILOptFunctionBuilder> {
+    : public TypeSubstCloner<VJPCloner::Implementation> {
   friend class VJPCloner;
   friend class PullbackCloner;
 
@@ -424,7 +424,7 @@ class VJPCloner::Implementation final
     auto *pbTupleVal = buildPullbackValueTupleValue(ccbi);
     // Create a new `checked_cast_branch` instruction.
     getBuilder().createCheckedCastBranch(
-        ccbi->getLoc(), ccbi->isExact(), ccbi->getIsolatedConformances(),
+        ccbi->getLoc(), ccbi->isExact(), ccbi->getCheckedCastOptions(),
         getOpValue(ccbi->getOperand()),
         getOpASTType(ccbi->getSourceFormalType()),
         getOpType(ccbi->getTargetLoweredType()),
@@ -441,7 +441,7 @@ class VJPCloner::Implementation final
     // Create a new `checked_cast_addr_branch` instruction.
     getBuilder().createCheckedCastAddrBranch(
         ccabi->getLoc(),
-        ccabi->getIsolatedConformances(),
+        ccabi->getCheckedCastOptions(),
         ccabi->getConsumptionKind(),
         getOpValue(ccabi->getSrc()), getOpASTType(ccabi->getSourceFormalType()),
         getOpValue(ccabi->getDest()),
@@ -460,6 +460,16 @@ class VJPCloner::Implementation final
       TypeSubstCloner::visitEndApplyInst(eai);
       return;
     }
+    // If the original function is a semantic member accessor, do standard
+    // cloning. Semantic member accessors have special pullback generation
+    // logic, so all `end_apply` instructions can be directly cloned to the VJP.
+    if (isSemanticMemberAccessor(original)) {
+      LLVM_DEBUG(getADDebugStream()
+                 << "Cloning `end_apply` in semantic member accessor:\n"
+                 << *eai << '\n');
+      TypeSubstCloner::visitEndApplyInst(eai);
+      return;
+    }
 
     Builder.setCurrentDebugScope(getOpScope(eai->getDebugScope()));
     auto loc = eai->getLoc();
@@ -607,6 +617,16 @@ class VJPCloner::Implementation final
       TypeSubstCloner::visitBeginApplyInst(bai);
       return;
     }
+    // If the original function is a semantic member accessor, do standard
+    // cloning. Semantic member accessors have special pullback generation
+    // logic, so all `begin_apply` instructions can be directly cloned to the VJP.
+    if (isSemanticMemberAccessor(original)) {
+      LLVM_DEBUG(getADDebugStream()
+                 << "Cloning `begin_apply` in semantic member accessor:\n"
+                 << *bai << '\n');
+      TypeSubstCloner::visitBeginApplyInst(bai);
+      return;
+    }
 
     Builder.setCurrentDebugScope(getOpScope(bai->getDebugScope()));
     auto loc = bai->getLoc();
@@ -1133,6 +1153,9 @@ SILFunction *VJPCloner::Implementation::createEmptyPullback() {
     case ResultConvention::Pack:
       conv = ParameterConvention::Pack_Guaranteed;
       break;
+    case ResultConvention::GuaranteedAddress:
+    case ResultConvention::Guaranteed:
+      llvm_unreachable("borrow accessor is not yet implemented");
     }
     return {tanType, conv};
   };
diff --git a/lib/SILOptimizer/FunctionSignatureTransforms/DeadArgumentTransform.cpp b/lib/SILOptimizer/FunctionSignatureTransforms/DeadArgumentTransform.cpp
index 70fce48010e15..551ae025c55f2 100644
--- a/lib/SILOptimizer/FunctionSignatureTransforms/DeadArgumentTransform.cpp
+++ b/lib/SILOptimizer/FunctionSignatureTransforms/DeadArgumentTransform.cpp
@@ -28,6 +28,16 @@ bool FunctionSignatureTransform::DeadArgumentAnalyzeParameters() {
 
   // Did we decide we should optimize any parameter?
   SILFunction *F = TransformDescriptor.OriginalFunction;
+
+  // If a function has lifetime dependencies, disable FSO's dead param
+  // optimization.  Dead params maybe dependency sources and we should not
+  // delete them. It is also problematic to dead code params that are not
+  // dependency sources, since lifetime dependent sources are stored as indices
+  // and deleting dead parameters will require recomputation of these indices.
+  if (F->getLoweredFunctionType()->hasLifetimeDependencies()) {
+    return false;
+  }
+
   bool SignatureOptimize = false;
   auto Args = F->begin()->getSILFunctionArguments();
   auto OrigShouldModifySelfArgument =
diff --git a/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialSpecializer.cpp b/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialSpecializer.cpp
index bc47af4d239d8..d580e12d4bc77 100644
--- a/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialSpecializer.cpp
+++ b/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialSpecializer.cpp
@@ -247,8 +247,9 @@ bool ExistentialSpecializer::canSpecializeCalleeFunction(FullApplySite &Apply) {
   if (Callee->getLoweredFunctionType()->hasErrorResult()) 
     return false;
 
-  /// Do not optimize always_inlinable functions.
-  if (Callee->getInlineStrategy() == Inline_t::AlwaysInline)
+  /// Do not optimize heuristic_always_inlinable functions.
+  if (Callee->getInlineStrategy() == Inline_t::HeuristicAlwaysInline ||
+      Callee->getInlineStrategy() == Inline_t::AlwaysInline)
     return false;
 
   /// Ignore externally linked functions with public_external or higher
diff --git a/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialTransform.cpp b/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialTransform.cpp
index 82aa8bad17db0..bd24ee9687a94 100644
--- a/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialTransform.cpp
+++ b/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialTransform.cpp
@@ -43,10 +43,8 @@ using llvm::SmallVectorImpl;
 /// Create a SILCloner for Existential Specilizer.
 namespace {
 class ExistentialSpecializerCloner
-    : public TypeSubstCloner<ExistentialSpecializerCloner,
-                             SILOptFunctionBuilder> {
-  using SuperTy =
-      TypeSubstCloner<ExistentialSpecializerCloner, SILOptFunctionBuilder>;
+    : public TypeSubstCloner<ExistentialSpecializerCloner> {
+  using SuperTy = TypeSubstCloner<ExistentialSpecializerCloner>;
   friend class SILInstructionVisitor<ExistentialSpecializerCloner>;
   friend class SILCloner<ExistentialSpecializerCloner>;
 
@@ -383,7 +381,7 @@ void ExistentialTransform::populateThunkBody() {
   SILModule &M = F->getModule();
 
   F->setThunk(IsSignatureOptimizedThunk);
-  F->setInlineStrategy(AlwaysInline);
+  F->setInlineStrategy(HeuristicAlwaysInline);
 
   /// Remove original body of F.
   for (auto It = F->begin(), End = F->end(); It != End;) {
@@ -535,7 +533,7 @@ void ExistentialTransform::populateThunkBody() {
           return type;
         }
       },
-      MakeAbstractConformanceForGenericType());
+      LookUpConformanceInModule());
 
   /// Perform the substitutions.
   auto SubstCalleeType = GenCalleeType->substGenericArgs(
diff --git a/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialTransform.h b/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialTransform.h
index 79ad59ec7ebda..08dad3cd73203 100644
--- a/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialTransform.h
+++ b/lib/SILOptimizer/FunctionSignatureTransforms/ExistentialTransform.h
@@ -1,4 +1,4 @@
-//===---- ExistentialSpecializerTransform.h - Existential Specializer -----===//
+//===--- ExistentialTransform.h - Existential Specializer -----------------===//
 //
 // This source file is part of the Swift.org open source project
 //
diff --git a/lib/SILOptimizer/FunctionSignatureTransforms/FunctionSignatureOpts.cpp b/lib/SILOptimizer/FunctionSignatureTransforms/FunctionSignatureOpts.cpp
index 8b1a63099680f..6f6ed836d5654 100644
--- a/lib/SILOptimizer/FunctionSignatureTransforms/FunctionSignatureOpts.cpp
+++ b/lib/SILOptimizer/FunctionSignatureTransforms/FunctionSignatureOpts.cpp
@@ -129,7 +129,8 @@ static bool canSpecializeFunction(SILFunction *F,
   // It is OK to specialize always inline functions if they are
   // used by partial_apply instructions.
   assert(!OptForPartialApply || FuncInfo);
-  if (F->getInlineStrategy() == Inline_t::AlwaysInline &&
+  if ((F->getInlineStrategy() == Inline_t::HeuristicAlwaysInline ||
+       F->getInlineStrategy() == Inline_t::AlwaysInline) &&
       (!OptForPartialApply || !FuncInfo->getMinPartialAppliedArgs()))
     return false;
 
@@ -590,7 +591,7 @@ void FunctionSignatureTransform::createFunctionSignatureOptimizedFunction() {
   // optimized. If we inline the thunk, we will get the benefit of calling
   // the signature optimized function without additional setup on the
   // caller side.
-  F->setInlineStrategy(AlwaysInline);
+  F->setInlineStrategy(HeuristicAlwaysInline);
   SILBasicBlock *ThunkBody = F->createBasicBlock();
   for (auto &ArgDesc : TransformDescriptor.ArgumentDescList) {
     auto *NewArg =
diff --git a/lib/SILOptimizer/FunctionSignatureTransforms/OwnedToGuaranteedTransform.cpp b/lib/SILOptimizer/FunctionSignatureTransforms/OwnedToGuaranteedTransform.cpp
index 0f9d449925eb5..268170041ec25 100644
--- a/lib/SILOptimizer/FunctionSignatureTransforms/OwnedToGuaranteedTransform.cpp
+++ b/lib/SILOptimizer/FunctionSignatureTransforms/OwnedToGuaranteedTransform.cpp
@@ -88,6 +88,15 @@ bool FunctionSignatureTransform::OwnedToGuaranteedAnalyzeParameters() {
       continue;
     }
 
+    // Make sure that an @in argument is not mutated otherwise than destroyed,
+    // because an @in_guaranteed argument must not be mutated.
+    if (A.hasConvention(SILArgumentConvention::Indirect_In) &&
+        // With opaque values, @in arguments can have non-address types.
+        A.Arg->getType().isAddress() &&
+        isIndirectArgumentMutated(A.Arg, /*ignoreDestroys=*/ true, /*defaultIsMutating=*/true)) {
+      continue;
+    }
+  
     // See if we can find a ref count equivalent strong_release or release_value
     // at the end of this function if our argument is an @owned parameter.
     // See if we can find a destroy_addr at the end of this function if our
diff --git a/lib/SILOptimizer/IPO/CMakeLists.txt b/lib/SILOptimizer/IPO/CMakeLists.txt
index a011d1d3daff3..91fcb857a7def 100644
--- a/lib/SILOptimizer/IPO/CMakeLists.txt
+++ b/lib/SILOptimizer/IPO/CMakeLists.txt
@@ -1,5 +1,4 @@
 target_sources(swiftSILOptimizer PRIVATE
-  CapturePropagation.cpp
   ClosureSpecializer.cpp
   CrossModuleOptimization.cpp
   DeadFunctionElimination.cpp
diff --git a/lib/SILOptimizer/IPO/CapturePropagation.cpp b/lib/SILOptimizer/IPO/CapturePropagation.cpp
deleted file mode 100644
index 6227e4a84fe0f..0000000000000
--- a/lib/SILOptimizer/IPO/CapturePropagation.cpp
+++ /dev/null
@@ -1,636 +0,0 @@
-//===--- CapturePropagation.cpp - Propagate closure capture constants -----===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "capture-prop"
-#include "swift/AST/GenericEnvironment.h"
-#include "swift/Basic/Assertions.h"
-#include "swift/Demangling/Demangle.h"
-#include "swift/SIL/SILCloner.h"
-#include "swift/SIL/SILInstruction.h"
-#include "swift/SIL/TypeSubstCloner.h"
-#include "swift/SILOptimizer/Analysis/ColdBlockInfo.h"
-#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
-#include "swift/SILOptimizer/PassManager/Passes.h"
-#include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/Generics.h"
-#include "swift/SILOptimizer/Utils/InstOptUtils.h"
-#include "swift/SILOptimizer/Utils/SILOptFunctionBuilder.h"
-#include "swift/SILOptimizer/Utils/SpecializationMangler.h"
-#include "llvm/ADT/MapVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Support/Debug.h"
-
-using namespace swift;
-
-STATISTIC(NumCapturesPropagated, "Number of constant captures propagated");
-
-namespace {
-/// Propagate constants through closure captures by specializing the partially
-/// applied function.
-/// Also optimize away partial_apply instructions where all partially applied
-/// arguments are dead.
-class CapturePropagation : public SILFunctionTransform
-{
-public:
-  void run() override;
-
-protected:
-  bool optimizePartialApply(PartialApplyInst *PAI);
-  SILFunction *specializeConstClosure(PartialApplyInst *PAI,
-                                      SILFunction *SubstF);
-  void rewritePartialApply(PartialApplyInst *PAI, SILFunction *SpecialF);
-};
-} // end anonymous namespace
-
-static SILInstruction *getConstant(SILValue V) {
-  if (auto I = dyn_cast<ThinToThickFunctionInst>(V))
-    return getConstant(I->getOperand());
-  if (auto I = dyn_cast<ConvertFunctionInst>(V))
-    return getConstant(I->getOperand());
-
-  if (auto *SLI = dyn_cast<StringLiteralInst>(V)) {
-    // We do not optimize string literals of length > 32 since we would need to
-    // encode them into the symbol name for uniqueness.
-    if (SLI->getValue().size() > 32)
-      return nullptr;
-    return SLI;
-  }
-
-  if (auto *lit = dyn_cast<LiteralInst>(V))
-    return lit;
-
-  if (auto *uc = dyn_cast<UpcastInst>(V))
-    V = uc->getOperand();
-
-  if (auto *oer = dyn_cast<OpenExistentialRefInst>(V))
-    V = oer->getOperand();
-
-  if (auto *kp = dyn_cast<KeyPathInst>(V)) {
-    // We could support operands, if they are constants, to enable propagation
-    // of subscript keypaths. This would require to add the operands in the
-    // mangling scheme.
-    // But currently it's not worth it because we do not optimize subscript
-    // keypaths in SILCombine.
-    if (kp->getPatternOperands().size() != 0)
-      return nullptr;
-    if (!kp->hasPattern())
-      return nullptr;
-    if (kp->getSubstitutions().hasAnySubstitutableParams())
-      return nullptr;
-    return kp;
-  }
-  return nullptr;
-}
-
-static std::string getClonedName(PartialApplyInst *PAI,
-                                 SerializedKind_t Serialized, SILFunction *F) {
-  auto P = Demangle::SpecializationPass::CapturePropagation;
-  Mangle::FunctionSignatureSpecializationMangler Mangler(F->getASTContext(), P, Serialized, F);
-
-  // We know that all arguments are literal insts.
-  unsigned argIdx = ApplySite(PAI).getCalleeArgIndexOfFirstAppliedArg();
-  for (auto arg : PAI->getArguments()) {
-    Mangler.setArgumentConstantProp(argIdx, getConstant(arg));
-    ++argIdx;
-  }
-  return Mangler.mangle();
-}
-
-namespace {
-/// Clone the partially applied function, replacing incoming arguments with
-/// literal constants.
-///
-/// The cloned literals will retain the SILLocation from the partial apply's
-/// caller, so the cloned function will have a mix of locations from different
-/// functions.
-class CapturePropagationCloner
-  : public TypeSubstCloner<CapturePropagationCloner, SILOptFunctionBuilder> {
-  using SuperTy =
-    TypeSubstCloner<CapturePropagationCloner, SILOptFunctionBuilder>;
-  friend class SILInstructionVisitor<CapturePropagationCloner>;
-  friend class SILCloner<CapturePropagationCloner>;
-
-  SILFunction *OrigF;
-  bool IsCloningConstant;
-public:
-  CapturePropagationCloner(SILFunction *OrigF, SILFunction *NewF,
-                           SubstitutionMap Subs)
-      : SuperTy(*NewF, *OrigF, Subs), OrigF(OrigF), IsCloningConstant(false) {}
-
-  void cloneClosure(OperandValueArrayRef Args);
-
-protected:
-  /// Literals cloned from the caller drop their location so the debug line
-  /// tables don't senselessly jump around. As a placeholder give them the
-  /// location of the newly cloned function.
-  SILLocation remapLocation(SILLocation InLoc) {
-    if (IsCloningConstant)
-      return getBuilder().getFunction().getLocation();
-    return InLoc;
-  }
-
-  /// Literals cloned from the caller take on the new function's debug scope.
-  void postProcess(SILInstruction *Orig, SILInstruction *Cloned) {
-    assert(IsCloningConstant == (Orig->getFunction() != OrigF) &&
-           "Expect only cloned constants from the caller function.");
-    SILClonerWithScopes<CapturePropagationCloner>::postProcess(Orig, Cloned);
-  }
-
-  const SILDebugScope *remapScope(const SILDebugScope *DS) {
-    if (IsCloningConstant)
-      return getBuilder().getFunction().getDebugScope();
-    else
-      return SILClonerWithScopes<CapturePropagationCloner>::remapScope(DS);
-  }
-
-  void cloneConstValue(SILValue Const);
-};
-} // end anonymous namespace
-
-/// Clone a constant value. Recursively walk the operand chain through cast
-/// instructions to ensure that all dependents are cloned. Note that the
-/// original value may not belong to the same function as the one being cloned
-/// by cloneClosure() (they may be from the partial apply caller).
-void CapturePropagationCloner::cloneConstValue(SILValue Val) {
-  assert(IsCloningConstant && "incorrect mode");
-
-  if (isValueCloned(Val))
-    return;
-
-  // TODO: MultiValueInstruction?
-  auto Inst = dyn_cast<SingleValueInstruction>(Val);
-  if (!Inst)
-    return;
-
-  if (Inst->getNumOperands() > 0) {
-    // Only handle single operands for simple recursion without a worklist.
-    assert(Inst->getNumOperands() == 1 && "expected single-operand cast");
-    cloneConstValue(Inst->getOperand(0));
-  }
-  visit(Inst);
-}
-
-/// Clone the original partially applied function into the new specialized
-/// function, replacing some arguments with literals.
-void CapturePropagationCloner::cloneClosure(
-    OperandValueArrayRef PartialApplyArgs) {
-
-  SILFunction &CloneF = getBuilder().getFunction();
-
-  // Create the entry basic block with the function arguments.
-  SILBasicBlock *OrigEntryBB = &*OrigF->begin();
-  SILBasicBlock *ClonedEntryBB = CloneF.createBasicBlock();
-  auto cloneConv = CloneF.getConventions();
-
-  // Only clone the arguments that remain in the new function type. The trailing
-  // arguments are now propagated through the partial apply.
-  assert(!IsCloningConstant && "incorrect mode");
-
-  SmallVector<SILValue, 4> entryArgs;
-  entryArgs.reserve(OrigEntryBB->getArguments().size());
-
-  unsigned ArgIdx = 0;
-  for (unsigned NewArgEnd = cloneConv.getNumSILArguments(); ArgIdx != NewArgEnd;
-       ++ArgIdx) {
-
-    SILArgument *Arg = OrigEntryBB->getArgument(ArgIdx);
-
-    auto *MappedValue = ClonedEntryBB->createFunctionArgument(
-        remapType(Arg->getType()), Arg->getDecl());
-    MappedValue->copyFlags(cast<SILFunctionArgument>(Arg));
-    entryArgs.push_back(MappedValue);
-  }
-  assert(OrigEntryBB->args_size() - ArgIdx == PartialApplyArgs.size()
-         && "unexpected number of partial apply arguments");
-
-  // Replace the rest of the old arguments with constants.
-  getBuilder().setInsertionPoint(ClonedEntryBB);
-  IsCloningConstant = true;
-  llvm::SmallVector<KeyPathInst *, 8> toDestroy;
-  for (SILValue PartialApplyArg : PartialApplyArgs) {
-    assert(getConstant(PartialApplyArg) &&
-           "expected a constant arg to partial apply");
-
-    cloneConstValue(PartialApplyArg);
-    if (auto *kp = dyn_cast<KeyPathInst>(getMappedValue(PartialApplyArg))) {
-      toDestroy.push_back(kp);
-    }
-
-    // The PartialApplyArg from the caller is now mapped to its cloned
-    // instruction.  Also map the original argument to the cloned instruction.
-    entryArgs.push_back(getMappedValue(PartialApplyArg));
-    ++ArgIdx;
-  }
-  IsCloningConstant = false;
-
-  // Clear information about cloned values from the caller function.
-  clearClonerState();
-
-  // Visit original BBs in depth-first preorder, starting with the
-  // entry block, cloning all instructions and terminators.
-  cloneFunctionBody(OrigF, ClonedEntryBB, entryArgs);
-  
-  // Destroy all the inserted keypaths at the function exits.
-  for (KeyPathInst *kpToDestroy : toDestroy) {
-    SILLocation loc = RegularLocation::getAutoGeneratedLocation();
-    for (SILBasicBlock &clonedBB : CloneF) {
-      TermInst *term = clonedBB.getTerminator();
-      if (term->isFunctionExiting()) {
-        SILBuilder builder(term);
-        if (CloneF.hasOwnership()) {
-          builder.createDestroyValue(loc, kpToDestroy);
-        } else {
-          builder.createStrongRelease(loc, kpToDestroy, builder.getDefaultAtomicity());
-        }
-      }
-    }
-  }
-}
-
-CanSILFunctionType getPartialApplyInterfaceResultType(PartialApplyInst *PAI) {
-  // The new partial_apply will no longer take any arguments--they are all
-  // expressed as literals. So its callee signature will be the same as its
-  // return signature.
-  auto FTy = PAI->getType().castTo<SILFunctionType>();
-  assert(!PAI->hasSubstitutions() ||
-         !PAI->getSubstitutionMap().getRecursiveProperties().hasArchetype());
-  FTy = cast<SILFunctionType>(
-    FTy->mapTypeOutOfContext()->getCanonicalType());
-  auto NewFTy = FTy;
-  return NewFTy;
-}
-
-/// Given a partial_apply instruction, create a specialized callee by removing
-/// all constant arguments and adding constant literals to the specialized
-/// function body.
-SILFunction *CapturePropagation::specializeConstClosure(PartialApplyInst *PAI,
-                                                        SILFunction *OrigF) {
-  SerializedKind_t serializedKind = PAI->getFunction()->getSerializedKind();
-  std::string Name = getClonedName(PAI, serializedKind, OrigF);
-
-  // See if we already have a version of this function in the module. If so,
-  // just return it.
-  if (auto *NewF = OrigF->getModule().lookUpFunction(Name)) {
-    assert(NewF->getSerializedKind() == serializedKind);
-    LLVM_DEBUG(llvm::dbgs()
-                 << "  Found an already specialized version of the callee: ";
-               NewF->printName(llvm::dbgs()); llvm::dbgs() << "\n");
-    return NewF;
-  }
-
-  // The new partial_apply will no longer take any arguments--they are all
-  // expressed as literals. So its callee signature will be the same as its
-  // return signature.
-  auto NewFTy = getPartialApplyInterfaceResultType(PAI);
-  NewFTy = NewFTy->getWithRepresentation(SILFunctionType::Representation::Thin);
-
-  GenericEnvironment *GenericEnv = nullptr;
-  if (NewFTy->getInvocationGenericSignature())
-    GenericEnv = OrigF->getGenericEnvironment();
-  SILOptFunctionBuilder FuncBuilder(*this);
-  SILFunction *NewF = FuncBuilder.createFunction(
-      SILLinkage::Shared, Name, NewFTy, GenericEnv, OrigF->getLocation(),
-      OrigF->isBare(), OrigF->isTransparent(), serializedKind, IsNotDynamic,
-      IsNotDistributed, IsNotRuntimeAccessible, OrigF->getEntryCount(),
-      OrigF->isThunk(), OrigF->getClassSubclassScope(),
-      OrigF->getInlineStrategy(), OrigF->getEffectsKind(),
-      /*InsertBefore*/ OrigF, OrigF->getDebugScope());
-  if (!OrigF->hasOwnership()) {
-    NewF->setOwnershipEliminated();
-  }
-  LLVM_DEBUG(llvm::dbgs() << "  Specialize callee as ";
-             NewF->printName(llvm::dbgs());
-             llvm::dbgs() << " " << NewFTy << "\n");
-
-  LLVM_DEBUG(if (PAI->hasSubstitutions()) {
-    llvm::dbgs() << "CapturePropagation of generic partial_apply:\n";
-    PAI->dumpInContext();
-  });
-  CapturePropagationCloner cloner(OrigF, NewF, PAI->getSubstitutionMap());
-  cloner.cloneClosure(PAI->getArguments());
-  assert(OrigF->getDebugScope()->Parent != NewF->getDebugScope()->Parent);
-  return NewF;
-}
-
-void CapturePropagation::rewritePartialApply(PartialApplyInst *OrigPAI,
-                                             SILFunction *SpecialF) {
-  LLVM_DEBUG(llvm::dbgs() << "\n  Rewriting a partial apply:\n";
-             OrigPAI->dumpInContext();
-             llvm::dbgs() << "   with special function: "
-                          << SpecialF->getName() << "\n";
-             llvm::dbgs() << "\nThe function being rewritten is:\n";
-             OrigPAI->getFunction()->dump());
-
-  SILBuilderWithScope Builder(OrigPAI);
-  auto FuncRef = Builder.createFunctionRef(OrigPAI->getLoc(), SpecialF);
-  auto *T2TF = Builder.createThinToThickFunction(OrigPAI->getLoc(), FuncRef,
-                                                 OrigPAI->getType());
-  OrigPAI->replaceAllUsesWith(T2TF);
-  
-  // Bypass any mark_dependence on the captures we specialized away.
-  //
-  // TODO: If we start to specialize away key path literals with operands
-  // (subscripts etc.), then a dependence of the new partial_apply on those
-  // operands may still exist. However, we should still leave the key path
-  // itself out of the dependency chain, and introduce dependencies on those
-  // operands instead, so that the key path object itself can be made dead.
-  for (auto user : T2TF->getUsersOfType<MarkDependenceInst>()) {
-    if (auto depUser = user->getBase()->getSingleUserOfType<PartialApplyInst>()){
-      if (depUser == OrigPAI) {
-        user->replaceAllUsesWith(T2TF);
-      }
-    }
-  }
-  
-  // Remove any dealloc_stack users.
-  SmallVector<Operand*, 16> Uses(T2TF->getUses());
-  for (auto *Use : Uses)
-    if (auto *DS = dyn_cast<DeallocStackInst>(Use->getUser()))
-      DS->eraseFromParent();
-  recursivelyDeleteTriviallyDeadInstructions(OrigPAI, true);
-  LLVM_DEBUG(llvm::dbgs() << "  Rewrote caller:\n" << *T2TF);
-}
-
-static bool isKeyPathFunction(FullApplySite FAS, SILValue keyPath) {
-  SILFunction *callee = FAS.getReferencedFunctionOrNull();
-  if (!callee)
-    return false;
-  if (callee->getName() == "swift_setAtWritableKeyPath" ||
-      callee->getName() == "swift_setAtReferenceWritableKeyPath") {
-    return FAS.getArgument(1) == keyPath;
-  }
-  if (callee->getName() == "swift_getAtKeyPath") {
-    return FAS.getArgument(2) == keyPath;
-  }
-  return false;
-}
-
-/// For now, we conservative only specialize if doing so can eliminate dynamic
-/// dispatch.
-///
-/// TODO: Check for other profitable constant propagation, like builtin compare.
-static bool isProfitable(SILFunction *Callee) {
-  SILBasicBlock *EntryBB = &*Callee->begin();
-  for (auto *Arg : EntryBB->getArguments()) {
-    for (auto *Operand : Arg->getUses()) {
-      if (FullApplySite FAS = FullApplySite::isa(Operand->getUser())) {
-        if (FAS.getCallee() == Operand->get())
-          return true;
-        if (isKeyPathFunction(FAS, Arg))
-          return true;
-      }
-    }
-  }
-  return false;
-}
-
-/// Returns true if block \p BB only contains a return or throw of the first
-/// block argument and side-effect-free instructions.
-static bool onlyContainsReturnOrThrowOfArg(SILBasicBlock *BB) {
-  for (SILInstruction &I : *BB) {
-    if (isa<ReturnInst>(&I) || isa<ThrowInst>(&I)) {
-      SILValue RetVal = I.getOperand(0);
-      return BB->getNumArguments() == 1 && RetVal == BB->getArgument(0);
-    }
-    if (I.mayHaveSideEffects() || isa<TermInst>(&I))
-      return false;
-  }
-  llvm_unreachable("should have seen a terminator instruction");
-}
-
-/// Checks if \p Orig is a thunk which calls another function but without
-/// passing the trailing \p numDeadParams dead parameters.
-/// If a generic specialization was performed for a generic capture,
-/// GenericSpecialized contains a tuple:
-/// (new specialized function, old function)
-static SILFunction *getSpecializedWithDeadParams(
-    SILOptFunctionBuilder &FuncBuilder,
-    PartialApplyInst *PAI, SILFunction *Orig, int numDeadParams,
-    std::pair<SILFunction *, SILFunction *> &GenericSpecialized) {
-  SILBasicBlock &EntryBB = *Orig->begin();
-  unsigned NumArgs = EntryBB.getNumArguments();
-
-  // Check if all dead parameters have trivial types. We don't support non-
-  // trivial types because it's very hard to find places where we can release
-  // those parameters (as a replacement for the removed partial_apply).
-  // TODO: maybe we can skip this restriction when we have semantic ARC.
-  for (unsigned Idx = NumArgs - numDeadParams; Idx < NumArgs; ++Idx) {
-    SILType ArgTy = EntryBB.getArgument(Idx)->getType();
-    if (!ArgTy.isTrivial(*Orig))
-      return nullptr;
-  }
-  SILFunction *Specialized = nullptr;
-  SILValue RetValue;
-
-  // Check all instruction of the entry block.
-  for (SILInstruction &I : EntryBB) {
-    if (auto FAS = FullApplySite::isa(&I)) {
-      // Check if this is the call of the specialized function.
-      // If the original partial_apply didn't have substitutions,
-      // also the specialized function must be not generic.
-      if (!PAI->hasSubstitutions() && FAS.hasSubstitutions())
-        return nullptr;
-
-      // Is it the only call?
-      if (Specialized)
-        return nullptr;
-
-      Specialized = FAS.getReferencedFunctionOrNull();
-      if (!Specialized)
-        return nullptr;
-
-      // Check if parameters are passes 1-to-1
-      unsigned NumArgs = FAS.getNumArguments();
-      if (EntryBB.getNumArguments() - numDeadParams != NumArgs)
-        return nullptr;
-
-      for (unsigned Idx = 0; Idx < NumArgs; ++Idx) {
-        if (FAS.getArgument(Idx) != (ValueBase *)EntryBB.getArgument(Idx))
-          return nullptr;
-      }
-
-      if (auto *TAI = dyn_cast<TryApplyInst>(&I)) {
-        // Check the normal and throw blocks of the try_apply.
-        if (onlyContainsReturnOrThrowOfArg(TAI->getNormalBB()) &&
-            onlyContainsReturnOrThrowOfArg(TAI->getErrorBB()))
-          return Specialized;
-        return nullptr;
-      }
-      assert(isa<ApplyInst>(&I) && "unknown FullApplySite instruction");
-      RetValue = cast<ApplyInst>(&I);
-      continue;
-    }
-    if (auto *RI = dyn_cast<ReturnInst>(&I)) {
-      // Check if we return the result of the apply.
-      if (RI->getOperand() != RetValue)
-        return nullptr;
-      continue;
-    }
-    if (I.mayHaveSideEffects() || isa<TermInst>(&I))
-      return nullptr;
-  }
-
-  auto Rep = Specialized->getLoweredFunctionType()->getRepresentation();
-  if (getSILFunctionLanguage(Rep) != SILFunctionLanguage::Swift)
-    return nullptr;
-
-  GenericSpecialized = std::make_pair(nullptr, nullptr);
-
-  if (PAI->hasSubstitutions()) {
-    if (Specialized->isExternalDeclaration())
-      return nullptr;
-    if (!Orig->shouldOptimize())
-      return nullptr;
-
-    // Perform a generic specialization of the Specialized function.
-    ReabstractionInfo ReInfo(
-        FuncBuilder.getModule().getSwiftModule(),
-        FuncBuilder.getModule().isWholeModule(), ApplySite(), Specialized,
-        PAI->getSubstitutionMap(), Specialized->getSerializedKind(),
-        /* ConvertIndirectToDirect */ false, /*dropMetatypeArgs=*/false);
-    GenericFuncSpecializer FuncSpecializer(FuncBuilder,
-                                           Specialized,
-                                           ReInfo.getClonerParamSubstitutionMap(),
-                                           ReInfo);
-
-    SILFunction *GenericSpecializedFunc = FuncSpecializer.trySpecialization();
-    if (!GenericSpecializedFunc)
-      return nullptr;
-    GenericSpecialized = std::make_pair(GenericSpecializedFunc, Specialized);
-    return GenericSpecializedFunc;
-  }
-  return Specialized;
-}
-
-bool CapturePropagation::optimizePartialApply(PartialApplyInst *PAI) {
-  SILFunction *SubstF = PAI->getReferencedFunctionOrNull();
-  if (!SubstF)
-    return false;
-  if (SubstF->isExternalDeclaration())
-    return false;
-
-  if (PAI->hasSubstitutions() &&
-      PAI->getSubstitutionMap().getRecursiveProperties().hasArchetype()) {
-    LLVM_DEBUG(llvm::dbgs()
-                 << "CapturePropagation: cannot handle partial specialization "
-                    "of partial_apply:\n";
-               PAI->dumpInContext());
-    return false;
-  }
-
-
-  // First possibility: Is it a partial_apply where all partially applied
-  // arguments are dead?
-  std::pair<SILFunction *, SILFunction *> GenericSpecialized;
-  SILOptFunctionBuilder FuncBuilder(*this);
-  if (auto *NewFunc = getSpecializedWithDeadParams(FuncBuilder, PAI, SubstF,
-                                                   PAI->getNumArguments(),
-                                                   GenericSpecialized)) {
-    // `partial_apply` can be rewritten to `thin_to_thick_function` only if the
-    // specialized callee is `@convention(thin)`.
-    if (NewFunc->getRepresentation() == SILFunctionTypeRepresentation::Thin) {
-      rewritePartialApply(PAI, NewFunc);
-      if (GenericSpecialized.first) {
-        // Notify the pass manager about the new function.
-        addFunctionToPassManagerWorklist(GenericSpecialized.first,
-                                         GenericSpecialized.second);
-      }
-      return true;
-    }
-  }
-
-  // Second possibility: Are all partially applied arguments constant?
-  llvm::SmallVector<SILInstruction *, 8> toDelete;
-  for (const Operand &argOp : PAI->getArgumentOperands()) {
-    SILInstruction *constInst = getConstant(argOp.get());
-    if (!constInst)
-      return false;
-    if (auto *kp = dyn_cast<KeyPathInst>(constInst)) {
-      auto argConv = ApplySite(PAI).getArgumentConvention(argOp).Value;
-      // Only handle the common case of a guaranteed keypath arguments. That
-      // refers to the callee function.
-      if (argConv != SILArgumentConvention::Direct_Guaranteed)
-        return false;
-
-      // For escaping closures:
-      // To keep things simple, we don't do a liverange analysis to insert
-      // compensating destroys of the keypath.
-      // Instead we require that the PAI is the only use of the keypath (= the
-      // common case). This allows us to just delete the now unused keypath
-      // instruction.
-      //
-      // For non-escaping closures:
-      // The keypath is not consumed by the PAI. We don't need to delete the
-      // keypath instruction in this pass, but let dead-object-elimination clean
-      // it up later.
-      if (!PAI->isOnStack()) {
-        SILInstruction *user = getSingleNonDebugUser(kp);
-        if (auto *oer = dyn_cast_or_null<OpenExistentialRefInst>(user))
-          user = getSingleNonDebugUser(oer);
-        if (auto *uc = dyn_cast_or_null<UpcastInst>(user))
-          user = getSingleNonDebugUser(uc);
-
-        if (user != PAI)
-          return false;
-        toDelete.push_back(kp);
-      }
-    }
-  }
-  if (!isProfitable(SubstF))
-    return false;
-
-  LLVM_DEBUG(llvm::dbgs() << "Specializing closure for constant arguments:\n"
-                          << "  " << SubstF->getName() << "\n"
-                          << *PAI);
-  ++NumCapturesPropagated;
-  SILFunction *NewF = specializeConstClosure(PAI, SubstF);
-  rewritePartialApply(PAI, NewF);
-
-  recursivelyDeleteTriviallyDeadInstructions(toDelete, /*force*/ true);
-
-  addFunctionToPassManagerWorklist(NewF, SubstF);
-  return true;
-}
-
-void CapturePropagation::run() {
-  DominanceAnalysis *DA = PM->getAnalysis<DominanceAnalysis>();
-  PostDominanceAnalysis *PDA = PM->getAnalysis<PostDominanceAnalysis>();
-  auto *F = getFunction();
-  bool HasChanged = false;
-
-  // Don't optimize functions that are marked with the opt.never attribute.
-  if (!F->shouldOptimize())
-    return;
-
-  // Cache cold blocks per function.
-  ColdBlockInfo ColdBlocks(DA, PDA);
-  ColdBlocks.analyze(F);
-  for (auto &BB : *F) {
-    if (ColdBlocks.isCold(&BB))
-      continue;
-
-    auto I = BB.begin();
-    while (I != BB.end()) {
-      SILInstruction *Inst = &*I;
-      ++I;
-      if (auto *PAI = dyn_cast<PartialApplyInst>(Inst))
-        HasChanged |= optimizePartialApply(PAI);
-    }
-  }
-  if (HasChanged) {
-    invalidateAnalysis(SILAnalysis::InvalidationKind::FunctionBody);
-  }
-}
-
-SILTransform *swift::createCapturePropagation() {
-  return new CapturePropagation();
-}
diff --git a/lib/SILOptimizer/IPO/ClosureSpecializer.cpp b/lib/SILOptimizer/IPO/ClosureSpecializer.cpp
index 57aeeaa753804..27751e95faed5 100644
--- a/lib/SILOptimizer/IPO/ClosureSpecializer.cpp
+++ b/lib/SILOptimizer/IPO/ClosureSpecializer.cpp
@@ -162,7 +162,7 @@ static int getSpecializationLevelRecursive(StringRef funcName,
       continue;
     Node *payload = param->getChild(1);
     if (payload->getKind() !=
-        Node::Kind::FunctionSignatureSpecializationParamPayload) {
+        Node::Kind::Identifier) {
       return SpecializationLevelLimit + 1; // unrecognized format
     }
     // Check if the specialized function is a specialization itself.
@@ -694,6 +694,19 @@ static bool isSupportedClosure(const SILInstruction *Closure) {
         return false;
       }
 
+      // Bail if it's an ObjectiveC block which might _not_ be copied onto the heap, i.e
+      // optimized by SimplifyCopyBlock. We can't do this because the optimization inserts
+      // retains+releases for captured arguments. That's not possible for stack-allocated blocks.
+      // TODO: avoid inserting retains+releases at all for captures of `partial_apply [on_stack]`
+      if (ArgTy.is<SILFunctionType>() &&
+          ArgTy.getFunctionRepresentation() == SILFunctionTypeRepresentation::Block &&
+          // A `copy_block` ensures that the block is copied onto the heap.
+          !isa<CopyBlockInst>(Arg) &&
+          // SimplifyCopyBlock only works for `partial_apply [on_stack]`.
+          PAI->isOnStack()) {
+        return false;
+      }
+
       // Only @inout/@inout_aliasable addresses are (currently) supported.
       // If our argument is an object, continue...
       if (ArgTy.isObject()) {
diff --git a/lib/SILOptimizer/IPO/CrossModuleOptimization.cpp b/lib/SILOptimizer/IPO/CrossModuleOptimization.cpp
index 22e2ed6f416ab..0e6eeaf7c3745 100644
--- a/lib/SILOptimizer/IPO/CrossModuleOptimization.cpp
+++ b/lib/SILOptimizer/IPO/CrossModuleOptimization.cpp
@@ -950,7 +950,9 @@ void CrossModuleOptimization::serializeInstruction(SILInstruction *inst,
     }
     serializeFunction(callee, canSerializeFlags);
     assert(isSerializedWithRightKind(M, callee) ||
-           isPackageOrPublic(callee->getLinkage()));
+           isPackageOrPublic(callee->getLinkage()) ||
+           M.getSwiftModule()->getASTContext().LangOpts.hasFeature(
+              Feature::Embedded));
     return;
   }
 
@@ -1005,7 +1007,10 @@ void CrossModuleOptimization::keepMethodAlive(SILDeclRef method) {
 void CrossModuleOptimization::makeFunctionUsableFromInline(SILFunction *function) {
   assert(canUseFromInline(function));
   if (!isAvailableExternally(function->getLinkage()) &&
-      !isPackageOrPublic(function->getLinkage())) {
+      !isPackageOrPublic(function->getLinkage()) &&
+      !(function->getLinkage() == SILLinkage::Shared &&
+        M.getSwiftModule()->getASTContext().LangOpts.hasFeature(
+            Feature::Embedded))) {
     function->setLinkage(SILLinkage::Public);
   }
 }
diff --git a/lib/SILOptimizer/IPO/DeadFunctionElimination.cpp b/lib/SILOptimizer/IPO/DeadFunctionElimination.cpp
index cfa93bde2983c..ca686d1e3841f 100644
--- a/lib/SILOptimizer/IPO/DeadFunctionElimination.cpp
+++ b/lib/SILOptimizer/IPO/DeadFunctionElimination.cpp
@@ -201,27 +201,13 @@ class DeadFunctionAndGlobalElimination {
           }
         } break;
 
-        case SILWitnessTable::AssociatedConformance: {
-          ProtocolConformanceRef CRef =
-             entry.getAssociatedConformanceWitness().Witness;
-          if (CRef.isConcrete())
-            ensureAliveConformance(CRef.getConcrete());
-          break;
-        }
+        case SILWitnessTable::AssociatedConformance:
         case SILWitnessTable::BaseProtocol:
-          ensureAliveConformance(entry.getBaseProtocolWitness().Witness);
-          break;
-
         case SILWitnessTable::Invalid:
         case SILWitnessTable::AssociatedType:
           break;
       }
     }
-
-    for (const auto &conf : WT->getConditionalConformances()) {
-      if (conf.Conformance.isConcrete())
-        ensureAliveConformance(conf.Conformance.getConcrete());
-    }
   }
 
   /// Marks the \p global and all functions, which are referenced from its
@@ -279,14 +265,6 @@ class DeadFunctionAndGlobalElimination {
       makeAlive(global);
   }
 
-  /// Marks a witness table as alive if it is not alive yet.
-  void ensureAliveConformance(const ProtocolConformance *C) {
-    SILWitnessTable *WT = Module->lookUpWitnessTable(C);
-    if (!WT || isAlive(WT))
-      return;
-    makeAlive(WT);
-  }
-
   /// Returns true if the implementation of method \p FD in class \p ImplCl
   /// may be called when the type of the class_method's operand is \p MethodCl.
   /// Both, \p MethodCl and \p ImplCl, may by null if not known or if it's a
@@ -321,8 +299,8 @@ class DeadFunctionAndGlobalElimination {
     for (FuncImpl &FImpl : mi->implementingFunctions) {
       if (!isAlive(FImpl.F) &&
           canHaveSameImplementation(FD, MethodCl,
-                                    FImpl.Impl.get<ClassDecl *>())) {
-        makeAlive(FImpl.F);
+                                    cast<ClassDecl *>(FImpl.Impl))) {
+        ensureAlive(FImpl.F);
       } else {
         allImplsAreCalled = false;
       }
@@ -341,9 +319,9 @@ class DeadFunctionAndGlobalElimination {
       if (auto Conf = FImpl.Impl.dyn_cast<ProtocolConformance *>()) {
         SILWitnessTable *WT = Module->lookUpWitnessTable(Conf);
         if (!WT || isAlive(WT))
-          makeAlive(FImpl.F);
+          ensureAlive(FImpl.F);
       } else {
-        makeAlive(FImpl.F);
+        ensureAlive(FImpl.F);
       }
     }
   }
diff --git a/lib/SILOptimizer/IPO/UsePrespecialized.cpp b/lib/SILOptimizer/IPO/UsePrespecialized.cpp
index 8317834311891..0ee9236aa3673 100644
--- a/lib/SILOptimizer/IPO/UsePrespecialized.cpp
+++ b/lib/SILOptimizer/IPO/UsePrespecialized.cpp
@@ -96,7 +96,7 @@ bool UsePrespecialized::replaceByPrespecialized(SILFunction &F) {
     ReabstractionInfo ReInfo(M.getSwiftModule(), M.isWholeModule(), AI,
                              ReferencedF, Subs, IsNotSerialized,
                              /*ConvertIndirectToDirect=*/ true,
-                             /*dropMetatypeArgs=*/ false);
+                             /*dropUnusedArguments=*/ false);
 
     if (!ReInfo.canBeSpecialized())
       continue;
diff --git a/lib/SILOptimizer/LoopTransforms/ArrayPropertyOpt.cpp b/lib/SILOptimizer/LoopTransforms/ArrayPropertyOpt.cpp
index 0ca35bb70c0a0..16bce8debebb4 100644
--- a/lib/SILOptimizer/LoopTransforms/ArrayPropertyOpt.cpp
+++ b/lib/SILOptimizer/LoopTransforms/ArrayPropertyOpt.cpp
@@ -61,6 +61,7 @@
 #include "swift/SIL/Projection.h"
 #include "swift/SIL/SILCloner.h"
 #include "swift/SILOptimizer/Analysis/ArraySemantic.h"
+#include "swift/SILOptimizer/Analysis/DeadEndBlocksAnalysis.h"
 #include "swift/SILOptimizer/Analysis/LoopAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/BasicBlockOptUtils.h"
@@ -87,6 +88,7 @@ class ArrayPropertiesAnalysis {
   SILLoop *Loop;
   SILBasicBlock *Preheader;
   DominanceInfo *DomTree;
+  DeadEndBlocks *deb;
 
   SinkAddressProjections sinkProj;
 
@@ -104,9 +106,9 @@ class ArrayPropertiesAnalysis {
   bool reachingBlocksComputed = false;
 
 public:
-  ArrayPropertiesAnalysis(SILLoop *L, DominanceAnalysis *DA)
+  ArrayPropertiesAnalysis(SILLoop *L, DominanceAnalysis *DA, DeadEndBlocks *deb)
       : Fun(L->getHeader()->getParent()), Loop(L), Preheader(nullptr),
-        DomTree(DA->get(Fun)), ReachingBlocks(Fun) {}
+        DomTree(DA->get(Fun)), deb(deb), ReachingBlocks(Fun) {}
 
   /// Check if it is profitable to specialize a loop when you see an apply
   /// instruction. We consider it is not profitable to specialize the loop when:
@@ -178,7 +180,7 @@ class ArrayPropertiesAnalysis {
       for (auto &Inst : *BB) {
         // Can't clone alloc_stack instructions whose dealloc_stack is outside
         // the loop.
-        if (!canDuplicateLoopInstruction(Loop, &Inst))
+        if (!canDuplicateLoopInstruction(Loop, &Inst, deb))
           return false;
 
         if (!sinkProj.analyzeAddressProjections(&Inst)) {
@@ -796,6 +798,7 @@ class SwiftArrayPropertyOptPass : public SILFunctionTransform {
       return;
 
     DominanceAnalysis *DA = PM->getAnalysis<DominanceAnalysis>();
+    DeadEndBlocks *deb = PM->getAnalysis<DeadEndBlocksAnalysis>()->get(Fn);
     SILLoopAnalysis *LA = PM->getAnalysis<SILLoopAnalysis>();
     SILLoopInfo *LI = LA->get(Fn);
 
@@ -808,7 +811,7 @@ class SwiftArrayPropertyOptPass : public SILFunctionTransform {
     // possible loop-nest.
     SmallVector<SILBasicBlock *, 16> HoistableLoopNests;
     std::function<void(SILLoop *)> processChildren = [&](SILLoop *L) {
-      ArrayPropertiesAnalysis Analysis(L, DA);
+      ArrayPropertiesAnalysis Analysis(L, DA, deb);
       if (Analysis.run()) {
         // Hoist in the current loop nest.
         HasChanged = true;
diff --git a/lib/SILOptimizer/LoopTransforms/BoundsCheckOpts.cpp b/lib/SILOptimizer/LoopTransforms/BoundsCheckOpts.cpp
index 0e6802be83382..4e90e982a8fa2 100644
--- a/lib/SILOptimizer/LoopTransforms/BoundsCheckOpts.cpp
+++ b/lib/SILOptimizer/LoopTransforms/BoundsCheckOpts.cpp
@@ -353,6 +353,11 @@ static bool isSignedLessEqual(SILValue Start, SILValue End, SILBasicBlock &BB) {
                                         m_Specific(Start), m_Specific(End)),
                             m_One())))
         return true;
+      // Try to match a cond_fail on "SGT Start, End".
+      if (match(CF->getOperand(),
+                m_ApplyInst(BuiltinValueKind::ICMP_SGT,
+                            m_Specific(Start), m_Specific(End))))
+        return true;
       // Try to match a cond_fail on "SLT End, Start".
       if (match(CF->getOperand(),
                 m_ApplyInst(BuiltinValueKind::ICMP_SLT, m_Specific(End),
@@ -368,6 +373,11 @@ static bool isSignedLessEqual(SILValue Start, SILValue End, SILBasicBlock &BB) {
                                           m_Specific(PreInclusiveEnd)),
                               m_One())))
           IsPreInclusiveEndLEQ = true;
+        if (match(CF->getOperand(),
+                  m_ApplyInst(BuiltinValueKind::ICMP_SGT,
+                              m_Specific(Start),
+                              m_Specific(PreInclusiveEnd))))
+          IsPreInclusiveEndLEQ = true;
         if (match(CF->getOperand(),
                   m_ApplyInst(BuiltinValueKind::ICMP_SLT,
                               m_Specific(PreInclusiveEnd), m_Specific(Start))))
@@ -379,6 +389,11 @@ static bool isSignedLessEqual(SILValue Start, SILValue End, SILBasicBlock &BB) {
                                           m_Specific(PreInclusiveEnd)),
                               m_One())))
           IsPreInclusiveEndGTEnd = true;
+        if (match(CF->getOperand(),
+                  m_ApplyInst(BuiltinValueKind::ICMP_SLE,
+                              m_Specific(End),
+                              m_Specific(PreInclusiveEnd))))
+          IsPreInclusiveEndGTEnd = true;
         if (IsPreInclusiveEndLEQ && IsPreInclusiveEndGTEnd)
           return true;
       }
@@ -558,7 +573,7 @@ static SILValue getSub(SILLocation Loc, SILValue Val, unsigned SubVal,
   SmallVector<SILValue, 4> Args(1, Val);
   Args.push_back(B.createIntegerLiteral(Loc, Val->getType(), SubVal));
   Args.push_back(B.createIntegerLiteral(
-      Loc, SILType::getBuiltinIntegerType(1, B.getASTContext()), -1));
+      Loc, SILType::getBuiltinIntegerType(1, B.getASTContext()), 1));
 
   auto *AI = B.createBuiltinBinaryFunctionWithOverflow(
       Loc, "ssub_with_overflow", Args);
@@ -570,7 +585,7 @@ static SILValue getAdd(SILLocation Loc, SILValue Val, unsigned AddVal,
   SmallVector<SILValue, 4> Args(1, Val);
   Args.push_back(B.createIntegerLiteral(Loc, Val->getType(), AddVal));
   Args.push_back(B.createIntegerLiteral(
-      Loc, SILType::getBuiltinIntegerType(1, B.getASTContext()), -1));
+      Loc, SILType::getBuiltinIntegerType(1, B.getASTContext()), 1));
 
   auto *AI = B.createBuiltinBinaryFunctionWithOverflow(
       Loc, "sadd_with_overflow", Args);
@@ -910,6 +925,12 @@ static bool isComparisonKnownFalse(BuiltinInst *Builtin,
       IndVar.Cmp != BuiltinValueKind::ICMP_EQ)
     return false;
 
+  if (match(Builtin, m_ApplyInst(BuiltinValueKind::ICMP_SGE,
+                             m_Specific(IndVar.HeaderVal),
+                             m_Specific(IndVar.End)))) {
+    return true;
+  }
+
   // Pattern match a false condition patterns that we can detect and optimize:
   // Iteration count < 0 (start)
   // Iteration count + 1 <= 0 (start)
@@ -1342,7 +1363,8 @@ BoundsCheckOpts::findAndOptimizeInductionVariables(SILLoop *loop) {
           if (isComparisonKnownTrue(builtin, *ivar)) {
             if (!trueVal)
               trueVal = builder.createIntegerLiteral(builtin->getLoc(),
-                                                     builtin->getType(), -1);
+                                                     builtin->getType(), -1,
+                                                     /*treatAsSigned=*/true);
             builtin->replaceAllUsesWith(trueVal);
             changed = true;
             continue;
diff --git a/lib/SILOptimizer/LoopTransforms/CMakeLists.txt b/lib/SILOptimizer/LoopTransforms/CMakeLists.txt
index d0f4068d880c2..b0de47af2f670 100644
--- a/lib/SILOptimizer/LoopTransforms/CMakeLists.txt
+++ b/lib/SILOptimizer/LoopTransforms/CMakeLists.txt
@@ -4,5 +4,4 @@ target_sources(swiftSILOptimizer PRIVATE
   COWArrayOpt.cpp
   LoopRotate.cpp
   LoopUnroll.cpp
-  LICM.cpp
   ForEachLoopUnroll.cpp)
diff --git a/lib/SILOptimizer/LoopTransforms/ForEachLoopUnroll.cpp b/lib/SILOptimizer/LoopTransforms/ForEachLoopUnroll.cpp
index 0b12222f412b0..b9a1314a2fd2e 100644
--- a/lib/SILOptimizer/LoopTransforms/ForEachLoopUnroll.cpp
+++ b/lib/SILOptimizer/LoopTransforms/ForEachLoopUnroll.cpp
@@ -337,7 +337,7 @@ void ArrayInfo::classifyUsesOfArray(SILValue arrayValue) {
     if (arrayOp.doesNotChangeArray())
       continue;
     
-    if (arrayOp.getKind() == swift::ArrayCallKind::kArrayFinalizeIntrinsic) {
+    if (arrayOp.getKind() == ArrayCallKind::kArrayFinalizeIntrinsic) {
       classifyUsesOfArray((ApplyInst *)arrayOp);
       continue;
     }
diff --git a/lib/SILOptimizer/LoopTransforms/LICM.cpp b/lib/SILOptimizer/LoopTransforms/LICM.cpp
deleted file mode 100644
index 6013b23658033..0000000000000
--- a/lib/SILOptimizer/LoopTransforms/LICM.cpp
+++ /dev/null
@@ -1,1601 +0,0 @@
-//===--- LICM.cpp - Loop invariant code motion ----------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "sil-licm"
-
-#include "swift/Basic/Assertions.h"
-#include "swift/SIL/Dominance.h"
-#include "swift/SIL/InstructionUtils.h"
-#include "swift/SIL/MemAccessUtils.h"
-#include "swift/SIL/Projection.h"
-#include "swift/SIL/SILArgument.h"
-#include "swift/SIL/SILBuilder.h"
-#include "swift/SIL/SILInstruction.h"
-#include "swift/SIL/BasicBlockBits.h"
-#include "swift/SILOptimizer/Analysis/AccessStorageAnalysis.h"
-#include "swift/SILOptimizer/Analysis/AliasAnalysis.h"
-#include "swift/SILOptimizer/Analysis/Analysis.h"
-#include "swift/SILOptimizer/Analysis/ArraySemantic.h"
-#include "swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h"
-#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
-#include "swift/SILOptimizer/Analysis/LoopAnalysis.h"
-#include "swift/SILOptimizer/PassManager/Passes.h"
-#include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CFGOptUtils.h"
-#include "swift/SILOptimizer/Utils/InstOptUtils.h"
-#include "swift/SILOptimizer/Utils/OwnershipOptUtils.h"
-#include "swift/SILOptimizer/Utils/SILSSAUpdater.h"
-
-#include "llvm/ADT/DepthFirstIterator.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/Support/Debug.h"
-
-#include "llvm/Support/CommandLine.h"
-
-using namespace swift;
-
-namespace {
-
-/// Instructions which can be hoisted:
-/// loads, function calls without side effects and (some) exclusivity checks
-using InstSet = llvm::SmallPtrSet<SILInstruction *, 8>;
-
-using InstVector = llvm::SmallVector<SILInstruction *, 8>;
-
-/// Returns true if the \p SideEffectInsts set contains any memory writes which
-/// may alias with the memory addressed by \a LI.
-template <SILInstructionKind K, typename T>
-static bool mayWriteTo(AliasAnalysis *AA, InstSet &SideEffectInsts,
-                       UnaryInstructionBase<K, T> *Inst) {
-  for (auto *I : SideEffectInsts)
-    if (AA->mayWriteToMemory(I, Inst->getOperand())) {
-      LLVM_DEBUG(llvm::dbgs() << "  mayWriteTo\n" << *I << " to "
-                              << *Inst << "\n");
-      return true;
-    }
-  return false;
-}
-
-/// Returns a non-null StoreInst if \p I is a store to \p accessPath.
-static StoreInst *isStoreToAccess(SILInstruction *I, AccessPath accessPath) {
-  auto *SI = dyn_cast<StoreInst>(I);
-  if (!SI)
-    return nullptr;
-
-  // TODO: handle StoreOwnershipQualifier::Init
-  if (SI->getOwnershipQualifier() == StoreOwnershipQualifier::Init)
-    return nullptr;
-
-  auto storeAccessPath = AccessPath::compute(SI->getDest());
-  if (accessPath != storeAccessPath)
-    return nullptr;
-
-  return SI;
-}
-
-struct LoadWithAccess {
-  LoadInst *li = nullptr;
-  AccessPath accessPath;
-
-  operator bool() { return li != nullptr; }
-};
-
-static LoadWithAccess doesLoadOverlapAccess(SILInstruction *I,
-                                            AccessPath accessPath) {
-  auto *LI = dyn_cast_or_null<LoadInst>(I);
-  if (!LI)
-    return LoadWithAccess();
-
-  // TODO: handle LoadOwnershipQualifier::Take
-  if (LI->getOwnershipQualifier() == LoadOwnershipQualifier::Take)
-    return LoadWithAccess();
-
-  AccessPath loadAccessPath = AccessPath::compute(LI->getOperand());
-  if (!loadAccessPath.isValid())
-    return LoadWithAccess();
-
-  // Don't use AccessPath::mayOverlap. We only want definite overlap.
-  if (loadAccessPath.contains(accessPath)
-      || accessPath.contains(loadAccessPath)) {
-    return {LI, loadAccessPath};
-  }
-  return LoadWithAccess();
-}
-
-/// Returns a valid LoadWithAccess if \p I is a load from \p accessPath or a
-/// projected address from \p accessPath.
-static LoadWithAccess isLoadWithinAccess(SILInstruction *I,
-                                         AccessPath accessPath) {
-  auto loadWithAccess = doesLoadOverlapAccess(I, accessPath);
-  if (!loadWithAccess)
-    return loadWithAccess;
-
-  // Make sure that any additional path components beyond the store's access
-  // path can be converted to value projections during projectLoadValue (it
-  // currently only supports StructElementAddr and TupleElementAddr).
-  auto storePathNode = accessPath.getPathNode();
-  auto loadPathNode = loadWithAccess.accessPath.getPathNode();
-  SILValue loadAddr = loadWithAccess.li->getOperand();
-  while (loadPathNode != storePathNode) {
-    if (!isa<StructElementAddrInst>(loadAddr)
-        && !isa<TupleElementAddrInst>(loadAddr)) {
-      return LoadWithAccess();
-    }
-    loadAddr = cast<SingleValueInstruction>(loadAddr)->getOperand(0);
-    loadPathNode = loadPathNode.getParent();
-  }
-  return loadWithAccess;
-}
-
-/// Returns true if all instructions in \p SideEffectInsts which may alias with
-/// \p access are either loads or stores from \p access.
-///
-/// \p storeAddr is only needed for AliasAnalysis until we have an interface
-/// that supports AccessPath.
-static bool isOnlyLoadedAndStored(AliasAnalysis *AA, InstSet &SideEffectInsts,
-                                  ArrayRef<LoadInst *> Loads,
-                                  ArrayRef<StoreInst *> Stores,
-                                  SILValue storeAddr, AccessPath accessPath) {
-  for (auto *I : SideEffectInsts) {
-    // Pass the original address value until we can fix AA
-    if (AA->mayReadOrWriteMemory(I, storeAddr)
-        && !isStoreToAccess(I, accessPath)
-        && !isLoadWithinAccess(I, accessPath)) {
-      return false;
-    }
-  }
-  for (auto *LI : Loads) {
-    if (AA->mayReadFromMemory(LI, storeAddr)
-        && !doesLoadOverlapAccess(LI, accessPath))
-      return false;
-  }
-  for (auto *SI : Stores) {
-    if (AA->mayWriteToMemory(SI, storeAddr) && !isStoreToAccess(SI, accessPath))
-      return false;
-  }
-  return true;
-}
-
-/// Returns true if the \p SideEffectInsts set contains any memory writes which
-/// may alias with any memory which is read by \p AI.
-/// Note: This function should only be called on a read-only apply!
-static bool mayWriteTo(AliasAnalysis *AA, BasicCalleeAnalysis *BCA,
-                       InstSet &SideEffectInsts, ApplyInst *AI) {
-
-  if (BCA->getMemoryBehavior(FullApplySite::isa(AI), /*observeRetains*/true) ==
-      MemoryBehavior::None) {
-    return false;
-  }
-
-  // Check if the memory addressed by the argument may alias any writes.
-  for (auto *inst : SideEffectInsts) {
-    switch (inst->getKind()) {
-      case SILInstructionKind::StoreInst: {
-        auto *si = cast<StoreInst>(inst);
-        if (si->getOwnershipQualifier() == StoreOwnershipQualifier::Assign)
-          return true;
-        if (AA->mayReadFromMemory(AI, si->getDest()))
-          return true;
-        break;
-      }
-      case SILInstructionKind::CopyAddrInst: {
-        auto *ca = cast<CopyAddrInst>(inst);
-        if (!ca->isInitializationOfDest())
-          return true;
-        if (AA->mayReadFromMemory(AI, ca->getDest()))
-          return true;
-        break;
-      }
-      case SILInstructionKind::ApplyInst:
-      case SILInstructionKind::BeginApplyInst:
-      case SILInstructionKind::TryApplyInst: {
-        if (BCA->getMemoryBehavior(FullApplySite::isa(inst), /*observeRetains*/false) >
-            MemoryBehavior::MayRead)
-          return true;
-        break;
-      }
-      case SILInstructionKind::CondFailInst:
-      case SILInstructionKind::StrongRetainInst:
-      case SILInstructionKind::UnmanagedRetainValueInst:
-      case SILInstructionKind::RetainValueInst:
-      case SILInstructionKind::StrongRetainUnownedInst:
-      case SILInstructionKind::FixLifetimeInst:
-      case SILInstructionKind::KeyPathInst:
-      case SILInstructionKind::DeallocStackInst:
-      case SILInstructionKind::DeallocStackRefInst:
-      case SILInstructionKind::DeallocRefInst:
-        break;
-      default:
-        if (inst->mayWriteToMemory())
-          return true;
-        break;
-    }
-  }
-  return false;
-}
-
-/// Returns true if \p sideEffectInst cannot be reordered with a call to a
-/// global initializer.
-static bool mayConflictWithGlobalInit(AliasAnalysis *AA,
-                    SILInstruction *sideEffectInst, SILInstruction *globalInitCall) {
-  if (auto *SI = dyn_cast<StoreInst>(sideEffectInst)) {
-    return AA->mayReadOrWriteMemory(globalInitCall, SI->getDest());
-  }
-  if (auto *LI = dyn_cast<LoadInst>(sideEffectInst)) {
-    return AA->mayWriteToMemory(globalInitCall, LI->getOperand());
-  }
-  if (isa<CondFailInst>(sideEffectInst))
-    return false;
-  return true;
-}
-
-/// Returns true if any of the instructions in \p sideEffectInsts which are
-/// post-dominated by a call to a global initializer cannot be reordered with
-/// the call.
-static bool mayConflictWithGlobalInit(AliasAnalysis *AA,
-                       InstSet &sideEffectInsts,
-                       SILInstruction *globalInitCall,
-                       SILBasicBlock *preHeader, PostDominanceInfo *PD) {
-  if (!PD->dominates(globalInitCall->getParent(), preHeader))
-    return true;
-
-  SILBasicBlock *globalInitBlock = globalInitCall->getParent();
-  for (auto *seInst : sideEffectInsts) {
-    // Only check instructions in blocks which are "before" (i.e. post-dominated
-    // by) the block which contains the init-call.
-    // Instructions which are before the call in the same block have already
-    // been checked.
-    if (PD->properlyDominates(globalInitBlock, seInst->getParent())) {
-      if (mayConflictWithGlobalInit(AA, seInst, globalInitCall))
-        return true;
-    }
-  }
-  return false;
-}
-
-/// Returns true if any of the instructions in \p sideEffectInsts cannot be
-/// reordered with a call to a global initializer (which is in the same basic
-/// block).
-static bool mayConflictWithGlobalInit(AliasAnalysis *AA,
-                       ArrayRef<SILInstruction *> sideEffectInsts,
-                       SILInstruction *globalInitCall) {
-  for (auto *seInst : sideEffectInsts) {
-    assert(seInst->getParent() == globalInitCall->getParent());
-    if (mayConflictWithGlobalInit(AA, seInst, globalInitCall))
-      return true;
-  }
-  return false;
-}
-
-// When Hoisting / Sinking,
-// Don't descend into control-dependent code.
-// Only traverse into basic blocks that dominate all exits.
-static void getDominatingBlocks(SmallVectorImpl<SILBasicBlock *> &domBlocks,
-                                SILLoop *Loop, DominanceInfo *DT) {
-  auto HeaderBB = Loop->getHeader();
-  auto DTRoot = DT->getNode(HeaderBB);
-  SmallVector<SILBasicBlock *, 8> ExitingAndLatchBBs;
-  Loop->getExitingAndLatchBlocks(ExitingAndLatchBBs);
-  for (llvm::df_iterator<DominanceInfoNode *> It = llvm::df_begin(DTRoot),
-                                              E = llvm::df_end(DTRoot);
-       It != E;) {
-    auto *CurBB = It->getBlock();
-
-    // Don't decent into control-dependent code. Only traverse into basic blocks
-    // that dominate all exits.
-    if (!std::all_of(ExitingAndLatchBBs.begin(), ExitingAndLatchBBs.end(),
-                     [=](SILBasicBlock *ExitBB) {
-          return DT->dominates(CurBB, ExitBB);
-        })) {
-      LLVM_DEBUG(llvm::dbgs() << "  skipping conditional block "
-                              << *CurBB << "\n");
-      It.skipChildren();
-      continue;
-    }
-    domBlocks.push_back(CurBB);
-    // Next block in dominator tree.
-    ++It;
-  }
-}
-
-/// Returns true if \p v is loop invariant in \p L.
-static bool isLoopInvariant(SILValue v, SILLoop *L) {
-  if (SILBasicBlock *parent = v->getParentBlock())
-    return !L->contains(parent);
-  return false;
-}
-
-static bool hoistInstruction(DominanceInfo *DT, SILInstruction *Inst,
-                             SILLoop *Loop, SILBasicBlock *&Preheader) {
-  auto Operands = Inst->getAllOperands();
-  if (!std::all_of(Operands.begin(), Operands.end(), [=](Operand &Op) {
-        return isLoopInvariant(Op.get(), Loop);
-      })) {
-    LLVM_DEBUG(llvm::dbgs() << "   loop variant operands\n");
-    return false;
-  }
-
-  auto mvBefore = Preheader->getTerminator();
-  ArraySemanticsCall semCall(Inst);
-  if (semCall.canHoist(mvBefore, DT)) {
-    semCall.hoist(mvBefore, DT);
-  } else {
-    Inst->moveBefore(mvBefore);
-  }
-  return true;
-}
-
-static bool hoistInstructions(SILLoop *Loop, DominanceInfo *DT,
-                              InstSet &HoistUpSet) {
-  LLVM_DEBUG(llvm::dbgs() << " Hoisting instructions.\n");
-  auto Preheader = Loop->getLoopPreheader();
-  assert(Preheader && "Expected a preheader");
-  bool Changed = false;
-  SmallVector<SILBasicBlock *, 8> domBlocks;
-  getDominatingBlocks(domBlocks, Loop, DT);
-
-  for (auto *CurBB : domBlocks) {
-    // We know that the block is guaranteed to be executed. Hoist if we can.
-    for (auto InstIt = CurBB->begin(), E = CurBB->end(); InstIt != E;) {
-      SILInstruction *Inst = &*InstIt;
-      ++InstIt;
-      LLVM_DEBUG(llvm::dbgs() << "  looking at " << *Inst);
-      if (!HoistUpSet.count(Inst)) {
-        continue;
-      }
-      if (!hoistInstruction(DT, Inst, Loop, Preheader)) {
-        continue;
-      }
-      LLVM_DEBUG(llvm::dbgs() << "Hoisted " << *Inst);
-      Changed = true;
-    }
-  }
-
-  return Changed;
-}
-
-/// Summary of side effect instructions occurring in the loop tree rooted at \p
-/// Loop. This includes all writes of the sub loops and the loop itself.
-struct LoopNestSummary {
-  SILLoop *Loop;
-  InstSet SideEffectInsts;
-
-  LoopNestSummary(SILLoop *Curr) : Loop(Curr) {}
-
-
-  void copySummary(LoopNestSummary &Other) {
-    SideEffectInsts.insert(Other.SideEffectInsts.begin(), Other.SideEffectInsts.end());
-  }
-
-  LoopNestSummary(const LoopNestSummary &) = delete;
-  LoopNestSummary &operator=(const LoopNestSummary &) = delete;
-  LoopNestSummary(LoopNestSummary &&) = delete;
-};
-
-static unsigned getEdgeIndex(SILBasicBlock *BB, SILBasicBlock *ExitingBB) {
-  auto Succs = ExitingBB->getSuccessors();
-  for (unsigned EdgeIdx = 0; EdgeIdx < Succs.size(); ++EdgeIdx) {
-    SILBasicBlock *CurrBB = Succs[EdgeIdx];
-    if (CurrBB == BB) {
-      return EdgeIdx;
-    }
-  }
-  llvm_unreachable("BB is not a Successor");
-}
-
-static bool sinkInstruction(DominanceInfo *DT,
-                            std::unique_ptr<LoopNestSummary> &LoopSummary,
-                            SILInstruction *Inst, SILLoopInfo *LI) {
-  auto *Loop = LoopSummary->Loop;
-  SmallVector<SILBasicBlock *, 8> ExitBBs;
-  Loop->getExitBlocks(ExitBBs);
-  SmallVector<SILBasicBlock *, 8> NewExitBBs;
-  SmallVector<SILBasicBlock *, 8> ExitingBBs;
-  Loop->getExitingBlocks(ExitingBBs);
-  auto *ExitBB = Loop->getExitBlock();
-
-  bool Changed = false;
-  for (auto *ExitingBB : ExitingBBs) {
-    SmallVector<SILBasicBlock *, 8> BBSuccessors;
-    auto Succs = ExitingBB->getSuccessors();
-    for (unsigned EdgeIdx = 0; EdgeIdx < Succs.size(); ++EdgeIdx) {
-      SILBasicBlock *BB = Succs[EdgeIdx];
-      BBSuccessors.push_back(BB);
-    }
-    while (!BBSuccessors.empty()) {
-      SILBasicBlock *BB = BBSuccessors.pop_back_val();
-      if (std::find(NewExitBBs.begin(), NewExitBBs.end(), BB) !=
-          NewExitBBs.end()) {
-        // Already got a copy there
-        continue;
-      }
-      auto EdgeIdx = getEdgeIndex(BB, ExitingBB);
-      SILBasicBlock *OutsideBB = nullptr;
-      if (std::find(ExitBBs.begin(), ExitBBs.end(), BB) != ExitBBs.end()) {
-        auto *SplitBB =
-            splitCriticalEdge(ExitingBB->getTerminator(), EdgeIdx, DT, LI);
-        OutsideBB = SplitBB ? SplitBB : BB;
-        NewExitBBs.push_back(OutsideBB);
-      }
-      if (!OutsideBB) {
-        continue;
-      }
-      // If OutsideBB already contains Inst -> skip
-      // This might happen if we have a conditional control flow
-      // And a pair
-      // We hoisted the first part, we can safely ignore sinking
-      auto matchPred = [&](SILInstruction &CurrIns) {
-        return Inst->isIdenticalTo(&CurrIns);
-      };
-      if (std::find_if(OutsideBB->begin(), OutsideBB->end(), matchPred) !=
-          OutsideBB->end()) {
-        LLVM_DEBUG(llvm::errs() << "  instruction already at exit BB "
-                                << *Inst);
-        ExitBB = nullptr;
-      } else if (ExitBB) {
-        // easy case
-        LLVM_DEBUG(llvm::errs() << "  moving instruction to exit BB " << *Inst);
-        Inst->moveBefore(&*OutsideBB->begin());
-      } else {
-        LLVM_DEBUG(llvm::errs() << "  cloning instruction to exit BB "
-                                << *Inst);
-        Inst->clone(&*OutsideBB->begin());
-      }
-      Changed = true;
-    }
-  }
-  if (Changed && !ExitBB) {
-    // Created clones of instruction
-    // Remove it from the side-effect set - dangling pointer
-    LoopSummary->SideEffectInsts.erase(Inst);
-    Inst->getParent()->erase(Inst);
-  }
-  return Changed;
-}
-
-static bool sinkInstructions(std::unique_ptr<LoopNestSummary> &LoopSummary,
-                             DominanceInfo *DT, SILLoopInfo *LI,
-                             InstVector &SinkDownSet) {
-  auto *Loop = LoopSummary->Loop;
-  LLVM_DEBUG(llvm::errs() << " Sink instructions attempt\n");
-  SmallVector<SILBasicBlock *, 8> domBlocks;
-  getDominatingBlocks(domBlocks, Loop, DT);
-
-  bool Changed = false;
-  for (auto *Inst : SinkDownSet) {
-    // only sink if the block is guaranteed to be executed.
-    if (std::find(domBlocks.begin(), domBlocks.end(), Inst->getParent()) ==
-        domBlocks.end()) {
-      continue;
-    }
-    Changed |= sinkInstruction(DT, LoopSummary, Inst, LI);
-  }
-
-  return Changed;
-}
-
-static void getEndAccesses(BeginAccessInst *BI,
-                           SmallVectorImpl<EndAccessInst *> &EndAccesses) {
-  for (auto Use : BI->getUses()) {
-    auto *User = Use->getUser();
-    auto *EI = dyn_cast<EndAccessInst>(User);
-    if (!EI) {
-      continue;
-    }
-    EndAccesses.push_back(EI);
-  }
-}
-
-static bool
-hoistSpecialInstruction(std::unique_ptr<LoopNestSummary> &LoopSummary,
-                        DominanceInfo *DT, SILLoopInfo *LI, InstVector &Special) {
-  auto *Loop = LoopSummary->Loop;
-  LLVM_DEBUG(llvm::errs() << " Hoist and Sink pairs attempt\n");
-  auto Preheader = Loop->getLoopPreheader();
-  assert(Preheader && "Expected a preheader");
-
-  bool Changed = false;
-
-  for (auto *Inst : Special) {
-    if (isa<BeginAccessInst>(Inst) && LoopSummary->Loop->hasNoExitBlocks()) {
-      // If no exit block, don't try to hoist BeginAccess because
-      // sinking EndAccess would fail later.
-      continue;
-    }
-    if (!hoistInstruction(DT, Inst, Loop, Preheader)) {
-      continue;
-    }
-    if (auto *BI = dyn_cast<BeginAccessInst>(Inst)) {
-      SmallVector<EndAccessInst *, 2> Ends;
-      getEndAccesses(BI, Ends);
-      LLVM_DEBUG(llvm::dbgs() << "Hoisted BeginAccess " << *BI);
-      for (auto *instSink : Ends) {
-        if (!sinkInstruction(DT, LoopSummary, instSink, LI)) {
-          llvm_unreachable("LICM: Could not perform must-sink instruction");
-        }
-      }
-      LLVM_DEBUG(llvm::errs() << " Successfully hoisted and sank pair\n");
-    } else {
-      LLVM_DEBUG(llvm::dbgs() << "Hoisted RefElementAddr "
-                              << *static_cast<RefElementAddrInst *>(Inst));
-    }
-    Changed = true;
-  }
-
-  return Changed;
-}
-
-/// Optimize the loop tree bottom up propagating loop's summaries up the
-/// loop tree.
-class LoopTreeOptimization {
-  llvm::DenseMap<SILLoop *, std::unique_ptr<LoopNestSummary>>
-      LoopNestSummaryMap;
-  SmallVector<SILLoop *, 8> BotUpWorkList;
-  InstSet toDelete;
-  SILLoopInfo *LoopInfo;
-  AliasAnalysis *AA;
-  BasicCalleeAnalysis *BCA;
-  DominanceInfo *DomTree;
-  PostDominanceAnalysis *PDA;
-  PostDominanceInfo *postDomTree = nullptr;
-  AccessStorageAnalysis *ASA;
-  bool Changed;
-
-  /// True if LICM is done on high-level SIL, i.e. semantic calls are not
-  /// inlined yet. In this case some semantic calls can be hoisted.
-  bool RunsOnHighLevelSIL;
-
-  /// Instructions that we may be able to hoist up
-  InstSet HoistUp;
-
-  /// Instructions that we may be able to sink down
-  InstVector SinkDown;
-
-  /// Load and store instructions that we may be able to move out of the loop.
-  /// All loads and stores within a block must be in instruction order to
-  /// simplify replacement of values after SSA update.
-  InstVector LoadsAndStores;
-
-  /// All access paths of the \p LoadsAndStores instructions.
-  llvm::SetVector<AccessPath> LoadAndStoreAddrs;
-
-  /// Hoistable Instructions that need special treatment
-  /// e.g. begin_access
-  InstVector SpecialHoist;
-
-public:
-  LoopTreeOptimization(SILLoop *TopLevelLoop, SILLoopInfo *LI,
-                       AliasAnalysis *AA, BasicCalleeAnalysis *BCA,
-                       DominanceInfo *DT, PostDominanceAnalysis *PDA,
-                       AccessStorageAnalysis *ASA,
-                       bool RunsOnHighLevelSil)
-      : LoopInfo(LI), AA(AA), BCA(BCA), DomTree(DT), PDA(PDA), ASA(ASA),
-        Changed(false), RunsOnHighLevelSIL(RunsOnHighLevelSil) {
-    // Collect loops for a recursive bottom-up traversal in the loop tree.
-    BotUpWorkList.push_back(TopLevelLoop);
-    for (unsigned i = 0; i < BotUpWorkList.size(); ++i) {
-      auto *L = BotUpWorkList[i];
-      for (auto *SubLoop : *L)
-        BotUpWorkList.push_back(SubLoop);
-    }
-  }
-
-  /// Optimize this loop tree.
-  bool optimize();
-
-protected:
-  /// Propagate the sub-loops' summaries up to the current loop.
-  void propagateSummaries(std::unique_ptr<LoopNestSummary> &CurrSummary);
-
-  bool isSafeReadOnlyApply(BasicCalleeAnalysis *BCA, ApplyInst *AI);
-
-  /// Collect a set of instructions that can be hoisted
-  void analyzeCurrentLoop(std::unique_ptr<LoopNestSummary> &CurrSummary);
-
-  SingleValueInstruction *splitLoad(SILValue splitAddress,
-                                    ArrayRef<AccessPath::Index> remainingPath,
-                                    SILBuilder &builder,
-                                    SmallVectorImpl<LoadInst *> &Loads,
-                                    unsigned ldStIdx);
-
-  /// Given an \p accessPath that is only loaded and stored, split loads that
-  /// are wider than \p accessPath.
-  bool splitLoads(SmallVectorImpl<LoadInst *> &Loads, AccessPath accessPath,
-                  SILValue storeAddr);
-
-  /// Optimize the current loop nest.
-  bool optimizeLoop(std::unique_ptr<LoopNestSummary> &CurrSummary);
-
-  /// Move all loads and stores from/to \p accessPath out of the \p loop.
-  void hoistLoadsAndStores(AccessPath accessPath, SILLoop *loop);
-
-  /// Move all loads and stores from all addresses in LoadAndStoreAddrs out of
-  /// the \p loop.
-  ///
-  /// This is a combination of load hoisting and store sinking, e.g.
-  /// \code
-  ///   preheader:
-  ///     br header_block
-  ///   header_block:
-  ///     %x = load %not_aliased_addr
-  ///     // use %x and define %y
-  ///     store %y to %not_aliased_addr
-  ///     ...
-  ///   exit_block:
-  /// \endcode
-  /// is transformed to:
-  /// \code
-  ///   preheader:
-  ///     %x = load %not_aliased_addr
-  ///     br header_block
-  ///   header_block:
-  ///     // use %x and define %y
-  ///     ...
-  ///   exit_block:
-  ///     store %y to %not_aliased_addr
-  /// \endcode
-  bool hoistAllLoadsAndStores(SILLoop *loop);
-};
-} // end anonymous namespace
-
-bool LoopTreeOptimization::optimize() {
-  // Process loops bottom up in the loop tree.
-  while (!BotUpWorkList.empty()) {
-    SILLoop *CurrentLoop = BotUpWorkList.pop_back_val();
-    LLVM_DEBUG(llvm::dbgs() << "Processing loop " << *CurrentLoop);
-
-    // Collect all summary of all sub loops of the current loop. Since we
-    // process the loop tree bottom up they are guaranteed to be available in
-    // the map.
-    auto CurrLoopSummary = std::make_unique<LoopNestSummary>(CurrentLoop);
-    propagateSummaries(CurrLoopSummary);
-
-    // If the current loop changed, then we might reveal more instr to hoist
-    // For example, a fix_lifetime's operand, if hoisted outside,
-    // Might allow us to sink the instruction out of the loop
-    bool currChanged = false;
-    do {
-      // Analyze the current loop for instructions that can be hoisted.
-      analyzeCurrentLoop(CurrLoopSummary);
-
-      currChanged = optimizeLoop(CurrLoopSummary);
-      if (currChanged) {
-        CurrLoopSummary->SideEffectInsts.clear();
-        Changed = true;
-      }
-
-      // Reset the data structures for next loop in the list
-      HoistUp.clear();
-      SinkDown.clear();
-      SpecialHoist.clear();
-    } while (currChanged);
-
-    // Store the summary for parent loops to use.
-    LoopNestSummaryMap[CurrentLoop] = std::move(CurrLoopSummary);
-  }
-  return Changed;
-}
-
-void LoopTreeOptimization::propagateSummaries(
-    std::unique_ptr<LoopNestSummary> &CurrSummary) {
-  for (auto *SubLoop : *CurrSummary->Loop) {
-    assert(LoopNestSummaryMap.count(SubLoop) && "Must have data for sub loops");
-    CurrSummary->copySummary(*LoopNestSummaryMap[SubLoop]);
-    LoopNestSummaryMap.erase(SubLoop);
-  }
-}
-
-bool LoopTreeOptimization::isSafeReadOnlyApply(BasicCalleeAnalysis *BCA, ApplyInst *AI) {
-  if (auto ri = AI->getSingleResult()) {
-    // We don't balance CSE'd apply results which return an owned value.
-    if (ri.value().getConvention() != ResultConvention::Unowned)
-      return false;
-  }
-
-  if (RunsOnHighLevelSIL) {
-    // The array-property-opt needs this semantic call inside the loop.
-    // After high-level SIL we can hoist it (if it's not inlined already).
-    if (ArraySemanticsCall(AI, "array.props.isNativeTypeChecked"))
-      return false;
-  }
-
-  return BCA->getMemoryBehavior(AI, /*observeRetains*/false) <=
-         MemoryBehavior::MayRead;
-}
-
-static void checkSideEffects(swift::SILInstruction &Inst,
-                      InstSet &SideEffectInsts,
-                      SmallVectorImpl<SILInstruction *> &sideEffectsInBlock) {
-  if (Inst.mayHaveSideEffects()) {
-    SideEffectInsts.insert(&Inst);
-    sideEffectsInBlock.push_back(&Inst);
-  }
-}
-
-/// Returns true if the \p Inst follows the default hoisting heuristic
-static bool canHoistUpDefault(SILInstruction *inst, SILLoop *Loop,
-                              DominanceInfo *DT, bool RunsOnHighLevelSil) {
-  auto Preheader = Loop->getLoopPreheader();
-  if (!Preheader) {
-    return false;
-  }
-
-  if (isa<TermInst>(inst) || isa<AllocationInst>(inst) ||
-      isa<DeallocationInst>(inst)) {
-    return false;
-  }
-
-  // We can’t hoist everything that is hoist-able
-  // The canHoist method does not do all the required analysis
-  // Some of the work is done at COW Array Opt
-  // TODO: Refactor COW Array Opt + canHoist - radar 41601468
-  ArraySemanticsCall semCall(inst);
-  switch (semCall.getKind()) {
-    case ArrayCallKind::kGetCount:
-    case ArrayCallKind::kGetCapacity:
-      if (RunsOnHighLevelSil && semCall.canHoist(Preheader->getTerminator(), DT))
-        return true;
-      break;
-    case ArrayCallKind::kArrayPropsIsNativeTypeChecked:
-      // The array-property-opt needs this semantic call inside the loop.
-      // After high-level SIL we can hoist it (if it's not inlined already).
-      if (RunsOnHighLevelSil)
-        return false;
-      break;
-    default:
-      break;
-  }
-
-  if (inst->getMemoryBehavior() == MemoryBehavior::None) {
-    return true;
-  }
-  return false;
-}
-
-// Check If all the end accesses of the given begin do not prevent hoisting
-// There are only two legal placements for the end access instructions:
-// 1) Inside the same loop (sink to loop exists)
-// Potential TODO: At loop exit block
-static bool handledEndAccesses(BeginAccessInst *BI, SILLoop *Loop) {
-  SmallVector<EndAccessInst *, 2> AllEnds;
-  getEndAccesses(BI, AllEnds);
-  if (AllEnds.empty()) {
-    return false;
-  }
-  for (auto *User : AllEnds) {
-    auto *BB = User->getParent();
-    if (Loop->getBlocksSet().count(BB) != 0) {
-      continue;
-    }
-    return false;
-  }
-  return true;
-}
-
-static bool isCoveredByScope(BeginAccessInst *BI, DominanceInfo *DT,
-                             SILInstruction *applyInstr) {
-  if (!DT->dominates(BI, applyInstr))
-    return false;
-  for (auto *EI : BI->getEndAccesses()) {
-    if (!DT->dominates(applyInstr, EI))
-      return false;
-  }
-  return true;
-}
-
-static bool analyzeBeginAccess(BeginAccessInst *BI,
-                               SmallVector<BeginAccessInst *, 8> &BeginAccesses,
-                               SmallVector<FullApplySite, 8> &fullApplies,
-                               InstSet &SideEffectInsts,
-                               AccessStorageAnalysis *ASA,
-                               DominanceInfo *DT) {
-  auto storage = AccessStorage::compute(BI->getSource());
-  if (!storage) {
-    return false;
-  }
-
-  auto BIAccessStorageNonNested = AccessStorage::compute(BI);
-  auto safeBeginPred = [&](BeginAccessInst *OtherBI) {
-    if (BI == OtherBI) {
-      return true;
-    }
-    return BIAccessStorageNonNested.isDistinctFrom(
-        AccessStorage::compute(OtherBI));
-  };
-
-  if (!std::all_of(BeginAccesses.begin(), BeginAccesses.end(), safeBeginPred))
-    return false;
-
-  for (auto fullApply : fullApplies) {
-    FunctionAccessStorage callSiteAccesses;
-    ASA->getCallSiteEffects(callSiteAccesses, fullApply);
-    SILAccessKind accessKind = BI->getAccessKind();
-    if (!callSiteAccesses.mayConflictWith(accessKind, storage))
-      continue;
-    // Check if we can ignore this conflict:
-    // If the apply is “sandwiched” between the begin and end access,
-    // there’s no reason we can’t hoist out of the loop.
-    auto *applyInstr = fullApply.getInstruction();
-    if (!isCoveredByScope(BI, DT, applyInstr))
-      return false;
-  }
-
-  // Check may releases
-  // Only class and global access that may alias would conflict
-  const AccessStorage::Kind kind = storage.getKind();
-  if (kind != AccessStorage::Class && kind != AccessStorage::Global) {
-    return true;
-  }
-  // TODO Introduce "Pure Swift" deinitializers
-  // We can then make use of alias information for instr's operands
-  // If they don't alias - we might get away with not recording a conflict
-  for (SILInstruction *I : SideEffectInsts) {
-    // we actually compute all SideEffectInsts in analyzeCurrentLoop
-    if (!I->mayRelease()) {
-      continue;
-    }
-    if (!isCoveredByScope(BI, DT, I))
-      return false;
-  }
-
-  return true;
-}
-
-// Analyzes current loop for hosting/sinking potential:
-// Computes set of instructions we may be able to move out of the loop
-// Important Note:
-// We can't bail out of this method! we have to run it on all loops.
-// We *need* to discover all SideEffectInsts -
-// even if the loop is otherwise skipped!
-// This is because outer loops will depend on the inner loop's writes.
-//
-// This may split some loads into smaller loads.
-void LoopTreeOptimization::analyzeCurrentLoop(
-    std::unique_ptr<LoopNestSummary> &CurrSummary) {
-  InstSet &sideEffects = CurrSummary->SideEffectInsts;
-  SILLoop *Loop = CurrSummary->Loop;
-  LLVM_DEBUG(llvm::dbgs() << " Analyzing accesses.\n");
-
-  auto *Preheader = Loop->getLoopPreheader();
-  if (!Preheader) {
-    // Can't hoist/sink instructions
-    return;
-  }
-
-  // Interesting instructions in the loop:
-  SmallVector<ApplyInst *, 8> ReadOnlyApplies;
-
-  // Contains either:
-  // * an apply to the addressor of the global
-  // * a builtin "once" of the global initializer
-  SmallVector<SILInstruction *, 8> globalInitCalls;
-
-  SmallVector<LoadInst *, 8> Loads;
-  SmallVector<StoreInst *, 8> Stores;
-  SmallVector<FixLifetimeInst *, 8> FixLifetimes;
-  SmallVector<BeginAccessInst *, 8> BeginAccesses;
-  SmallVector<FullApplySite, 8> fullApplies;
-
-  for (auto *BB : Loop->getBlocks()) {
-    SmallVector<SILInstruction *, 8> sideEffectsInBlock;
-    for (auto &Inst : *BB) {
-      if (hasOwnershipOperandsOrResults(&Inst)) {
-        checkSideEffects(Inst, sideEffects, sideEffectsInBlock);
-        // Collect fullApplies to be checked in analyzeBeginAccess
-        if (auto fullApply = FullApplySite::isa(&Inst)) {
-          fullApplies.push_back(fullApply);
-        }
-        continue;
-      }
-      switch (Inst.getKind()) {
-      case SILInstructionKind::FixLifetimeInst: {
-        auto *FL = cast<FixLifetimeInst>(&Inst);
-        if (DomTree->dominates(FL->getOperand()->getParentBlock(), Preheader))
-          FixLifetimes.push_back(FL);
-        // We can ignore the side effects of FixLifetimes
-        break;
-      }
-      case SILInstructionKind::LoadInst:
-        Loads.push_back(cast<LoadInst>(&Inst));
-        LoadsAndStores.push_back(&Inst);
-        break;
-      case SILInstructionKind::StoreInst: {
-        auto *store = cast<StoreInst>(&Inst);
-        switch (store->getOwnershipQualifier()) {
-          case StoreOwnershipQualifier::Assign:
-          case StoreOwnershipQualifier::Init:
-            // Currently not supported.
-            continue;
-          case StoreOwnershipQualifier::Unqualified:
-          case StoreOwnershipQualifier::Trivial:
-            break;
-        }
-        Stores.push_back(store);
-        LoadsAndStores.push_back(&Inst);
-        checkSideEffects(Inst, sideEffects, sideEffectsInBlock);
-        break;
-      }
-      case SILInstructionKind::BeginAccessInst:
-        BeginAccesses.push_back(cast<BeginAccessInst>(&Inst));
-        checkSideEffects(Inst, sideEffects, sideEffectsInBlock);
-        break;
-      case SILInstructionKind::RefElementAddrInst:
-        SpecialHoist.push_back(cast<RefElementAddrInst>(&Inst));
-        break;
-      case swift::SILInstructionKind::CondFailInst:
-        // We can (and must) hoist cond_fail instructions if the operand is
-        // invariant. We must hoist them so that we preserve memory safety. A
-        // cond_fail that would have protected (executed before) a memory access
-        // must - after hoisting - also be executed before said access.
-        HoistUp.insert(&Inst);
-        checkSideEffects(Inst, sideEffects, sideEffectsInBlock);
-        break;
-      case SILInstructionKind::ApplyInst: {
-        auto *AI = cast<ApplyInst>(&Inst);
-        if (isSafeReadOnlyApply(BCA, AI)) {
-          ReadOnlyApplies.push_back(AI);
-        } else if (SILFunction *callee = AI->getReferencedFunctionOrNull()) {
-          // Calls to global inits are different because we don't care about
-          // side effects which are "after" the call in the loop.
-          if (callee->isGlobalInit() &&
-              // Check against side-effects within the same block.
-              // Side-effects in other blocks are checked later (after we
-              // scanned all blocks of the loop).
-              !mayConflictWithGlobalInit(AA, sideEffectsInBlock, &Inst))
-            globalInitCalls.push_back(&Inst);
-        }
-        // check for array semantics and side effects - same as default
-        LLVM_FALLTHROUGH;
-      }
-      default:
-        if (auto fullApply = FullApplySite::isa(&Inst)) {
-          fullApplies.push_back(fullApply);
-        } else if (auto *bi = dyn_cast<BuiltinInst>(&Inst)) {
-          switch (bi->getBuiltinInfo().ID) {
-            case BuiltinValueKind::Once:
-            case BuiltinValueKind::OnceWithContext:
-              if (!mayConflictWithGlobalInit(AA, sideEffectsInBlock, &Inst))
-                globalInitCalls.push_back(&Inst);
-              break;
-            default:
-              break;
-          }
-        }
-
-        checkSideEffects(Inst, sideEffects, sideEffectsInBlock);
-        if (canHoistUpDefault(&Inst, Loop, DomTree, RunsOnHighLevelSIL)) {
-          HoistUp.insert(&Inst);
-        }
-        break;
-      }
-    }
-  }
-
-  // Avoid quadratic complexity in corner cases. Usually, this limit will not be exceeded.
-  if (ReadOnlyApplies.size() * sideEffects.size() < 8000) {
-    for (auto *AI : ReadOnlyApplies) {
-      if (!mayWriteTo(AA, BCA, sideEffects, AI)) {
-        HoistUp.insert(AI);
-      }
-    }
-  }
-  // Avoid quadratic complexity in corner cases. Usually, this limit will not be exceeded.
-  if (Loads.size() * sideEffects.size() < 8000) {
-    for (auto *LI : Loads) {
-      if (!mayWriteTo(AA, sideEffects, LI)) {
-        HoistUp.insert(LI);
-      }
-    }
-  }
-
-  if (!globalInitCalls.empty()) {
-    if (!postDomTree) {
-      postDomTree = PDA->get(Preheader->getParent());
-    }
-    if (postDomTree->getRootNode()) {
-      for (SILInstruction *ginitCall : globalInitCalls) {
-        // Check against side effects which are "before" (i.e. post-dominated
-        // by) the global initializer call.
-        if (!mayConflictWithGlobalInit(AA, sideEffects, ginitCall, Preheader,
-             postDomTree)) {
-          HoistUp.insert(ginitCall);
-        }
-      }
-    }
-  }
-
-  // Collect memory locations for which we can move all loads and stores out
-  // of the loop.
-  //
-  // Note: The Loads set and LoadsAndStores set may mutate during this loop.
-  for (StoreInst *SI : Stores) {
-    // Use AccessPathWithBase to recover a base address that can be used for
-    // newly inserted memory operations. If we instead teach hoistLoadsAndStores
-    // how to rematerialize global_addr, then we don't need this base.
-    auto access = AccessPathWithBase::compute(SI->getDest());
-    auto accessPath = access.accessPath;
-    if (accessPath.isValid() &&
-        (access.base && isLoopInvariant(access.base, Loop))) {
-      if (isOnlyLoadedAndStored(AA, sideEffects, Loads, Stores, SI->getDest(),
-                                accessPath)) {
-        if (!LoadAndStoreAddrs.count(accessPath)) {
-          if (splitLoads(Loads, accessPath, SI->getDest())) {
-            LoadAndStoreAddrs.insert(accessPath);
-          }
-        }
-      }
-    }
-  }
-  if (!FixLifetimes.empty()) {
-    bool sideEffectsMayRelease =
-        std::any_of(sideEffects.begin(), sideEffects.end(),
-                    [&](SILInstruction *W) { return W->mayRelease(); });
-    for (auto *FL : FixLifetimes) {
-      if (!FL->getOperand()->getType().isAddress())
-        continue;
-      if (!sideEffectsMayRelease || !mayWriteTo(AA, sideEffects, FL)) {
-        SinkDown.push_back(FL);
-      }
-    }
-  }
-  for (auto *BI : BeginAccesses) {
-    if (!handledEndAccesses(BI, Loop)) {
-      LLVM_DEBUG(llvm::dbgs() << "Skipping: " << *BI);
-      LLVM_DEBUG(llvm::dbgs() << "Some end accesses can't be handled\n");
-      continue;
-    }
-    if (analyzeBeginAccess(BI, BeginAccesses, fullApplies, sideEffects, ASA,
-                           DomTree)) {
-      SpecialHoist.push_back(BI);
-    }
-  }
-}
-
-// Recursively determine whether the innerAddress is a direct tuple or struct
-// projection chain from outerPath. Populate \p reversePathIndices with the path
-// difference.
-static bool
-computeInnerAccessPath(AccessPath::PathNode outerPath,
-                       AccessPath::PathNode innerPath, SILValue innerAddress,
-                       SmallVectorImpl<AccessPath::Index> &reversePathIndices) {
-  if (outerPath == innerPath)
-    return true;
-
-  auto *sea = dyn_cast<StructElementAddrInst>(innerAddress);
-
-  if (sea && sea->getStructDecl()->hasUnreferenceableStorage()) {
-    return false;
-  }
-
-  if (!sea && !isa<TupleElementAddrInst>(innerAddress)) {
-    return false;
-  }
-  assert(ProjectionIndex(innerAddress).Index
-         == innerPath.getIndex().getSubObjectIndex());
-
-  reversePathIndices.push_back(innerPath.getIndex());
-  SILValue srcAddr = cast<SingleValueInstruction>(innerAddress)->getOperand(0);
-  if (!computeInnerAccessPath(outerPath, innerPath.getParent(), srcAddr,
-                              reversePathIndices)) {
-    return false;
-  }
-  return true;
-}
-
-/// Split a load from \p outerAddress recursively following remainingPath.
-///
-/// Creates a load with identical \p accessPath and a set of
-/// non-overlapping loads. Add the new non-overlapping loads to HoistUp.
-///
-/// \p ldstIdx is the index into LoadsAndStores of the original outer load.
-///
-/// Return the aggregate produced by merging the loads.
-SingleValueInstruction *LoopTreeOptimization::splitLoad(
-    SILValue splitAddress, ArrayRef<AccessPath::Index> remainingPath,
-    SILBuilder &builder, SmallVectorImpl<LoadInst *> &Loads, unsigned ldstIdx) {
-  auto loc = LoadsAndStores[ldstIdx]->getLoc();
-  LoadOwnershipQualifier ownership = builder.getFunction().hasOwnership() ?
-      LoadOwnershipQualifier::Trivial :
-      LoadOwnershipQualifier::Unqualified;
-
-  // Recurse until we have a load that matches accessPath.
-  if (remainingPath.empty()) {
-    // Create a load that matches the stored access path.
-    LoadInst *load = builder.createLoad(loc, splitAddress, ownership);
-    Loads.push_back(load);
-    // Replace the outer load in the list of loads and stores to hoist and
-    // sink. LoadsAndStores must remain in instruction order.
-    LoadsAndStores[ldstIdx] = load;
-    LLVM_DEBUG(llvm::dbgs() << "Created load from stored path: " << *load);
-    return load;
-  }
-  auto recordDisjointLoad = [&](LoadInst *newLoad) {
-    Loads.push_back(newLoad);
-    LoadsAndStores.insert(LoadsAndStores.begin() + ldstIdx + 1, newLoad);
-  };
-  auto subIndex = remainingPath.back().getSubObjectIndex();
-  SILType loadTy = splitAddress->getType();
-  if (CanTupleType tupleTy = loadTy.getAs<TupleType>()) {
-    SmallVector<SILValue, 4> elements;
-    for (int tupleIdx : range(tupleTy->getNumElements())) {
-      auto *projection = builder.createTupleElementAddr(
-          loc, splitAddress, tupleIdx, loadTy.getTupleElementType(tupleIdx));
-      SILValue elementVal;
-      if (tupleIdx == subIndex) {
-        elementVal = splitLoad(projection, remainingPath.drop_back(), builder,
-                               Loads, ldstIdx);
-      } else {
-        elementVal = builder.createLoad(loc, projection, ownership);
-        recordDisjointLoad(cast<LoadInst>(elementVal));
-      }
-      elements.push_back(elementVal);
-    }
-    return builder.createTuple(loc, elements);
-  }
-  auto structTy = loadTy.getStructOrBoundGenericStruct();
-  assert(structTy && "tuple and struct elements are checked earlier");
-  auto &module = builder.getModule();
-  auto expansionContext = builder.getFunction().getTypeExpansionContext();
-
-  SmallVector<SILValue, 4> elements;
-  int fieldIdx = 0;
-  for (auto *field : structTy->getStoredProperties()) {
-    SILType fieldTy = loadTy.getFieldType(field, module, expansionContext);
-    auto *projection =
-        builder.createStructElementAddr(loc, splitAddress, field, fieldTy);
-    SILValue fieldVal;
-    if (fieldIdx++ == subIndex)
-      fieldVal = splitLoad(projection, remainingPath.drop_back(), builder,
-                           Loads, ldstIdx);
-    else {
-      fieldVal = builder.createLoad(loc, projection, ownership);
-      recordDisjointLoad(cast<LoadInst>(fieldVal));
-    }
-    elements.push_back(fieldVal);
-  }
-  return builder.createStruct(loc, loadTy.getObjectType(), elements);
-}
-
-/// Find all loads that contain \p accessPath. Split them into a load with
-/// identical accessPath and a set of non-overlapping loads. Add the new
-/// non-overlapping loads to LoadsAndStores and HoistUp.
-///
-/// TODO: The \p storeAddr parameter is only needed until we have an
-/// AliasAnalysis interface that handles AccessPath.
-bool LoopTreeOptimization::splitLoads(SmallVectorImpl<LoadInst *> &Loads,
-                                      AccessPath accessPath,
-                                      SILValue storeAddr) {
-  // The Loads set may mutate during this loop, but we only want to visit the
-  // original set.
-  for (unsigned loadsIdx = 0, endIdx = Loads.size(); loadsIdx != endIdx;
-       ++loadsIdx) {
-    auto *load = Loads[loadsIdx];
-    if (toDelete.count(load))
-      continue;
-
-    if (!AA->mayReadFromMemory(load, storeAddr))
-      continue;
-
-    AccessPath loadAccessPath = AccessPath::compute(load->getOperand());
-    if (accessPath.contains(loadAccessPath))
-      continue;
-
-    assert(loadAccessPath.contains(accessPath));
-    LLVM_DEBUG(llvm::dbgs() << "Overlaps with loop stores: " << *load);
-    SmallVector<AccessPath::Index, 4> reversePathIndices;
-    if (!computeInnerAccessPath(loadAccessPath.getPathNode(),
-                                accessPath.getPathNode(), storeAddr,
-                                reversePathIndices)) {
-      return false;
-    }
-    // Found a load wider than the store to accessPath.
-    //
-    // SplitLoads is called for each unique access path in the loop that is
-    // only loaded from and stored to and this loop takes time proportional to:
-    //   num-wide-loads x num-fields x num-loop-memops
-    //
-    // For each load wider than the store, it creates a new load for each field
-    // in that type. Each new load is inserted in the LoadsAndStores vector.  To
-    // avoid super-linear behavior for large types (e.g. giant tuples), limit
-    // growth of new loads to an arbitrary constant factor per access path.
-    if (Loads.size() >= endIdx + 6) {
-      LLVM_DEBUG(llvm::dbgs() << "...Refusing to split more loads\n");
-      return false;
-    }
-    LLVM_DEBUG(llvm::dbgs() << "...Splitting load\n");
-
-    unsigned ldstIdx = [this, load]() {
-      auto ldstIter = llvm::find(LoadsAndStores, load);
-      assert(ldstIter != LoadsAndStores.end() && "outerLoad missing");
-      return std::distance(LoadsAndStores.begin(), ldstIter);
-    }();
-
-    SILBuilderWithScope builder(load);
-
-    SILValue aggregateVal = splitLoad(load->getOperand(), reversePathIndices,
-                                      builder, Loads, ldstIdx);
-
-    load->replaceAllUsesWith(aggregateVal);
-    auto iterAndInserted = toDelete.insert(load);
-    (void)iterAndInserted;
-    assert(iterAndInserted.second && "the same load should only be split once");
-  }
-  return true;
-}
-
-bool LoopTreeOptimization::optimizeLoop(
-    std::unique_ptr<LoopNestSummary> &CurrSummary) {
-  auto *CurrentLoop = CurrSummary->Loop;
-  // We only support Loops with a preheader
-  if (!CurrentLoop->getLoopPreheader())
-    return false;
-  bool currChanged = false;
-  if (hoistAllLoadsAndStores(CurrentLoop))
-    return true;
-
-  currChanged |= hoistInstructions(CurrentLoop, DomTree, HoistUp);
-  currChanged |= sinkInstructions(CurrSummary, DomTree, LoopInfo, SinkDown);
-  currChanged |=
-      hoistSpecialInstruction(CurrSummary, DomTree, LoopInfo, SpecialHoist);
-
-  assert(toDelete.empty() && "only hostAllLoadsAndStores deletes");
-  return currChanged;
-}
-
-/// Creates a value projection from \p rootVal based on the address projection
-/// from \a rootVal to \a addr.
-static SILValue projectLoadValue(SILValue addr, AccessPath accessPath,
-                                 SILValue rootVal, AccessPath rootAccessPath,
-                                 SILInstruction *beforeInst) {
-  if (accessPath == rootAccessPath)
-    return rootVal;
-
-  auto pathNode = accessPath.getPathNode();
-  int elementIdx = pathNode.getIndex().getSubObjectIndex();
-  if (auto *SEI = dyn_cast<StructElementAddrInst>(addr)) {
-    assert(ProjectionIndex(SEI).Index == elementIdx);
-    SILValue val = projectLoadValue(
-        SEI->getOperand(),
-        AccessPath(accessPath.getStorage(), pathNode.getParent(),
-                   accessPath.getOffset()),
-        rootVal, rootAccessPath, beforeInst);
-    SILBuilder B(beforeInst);
-    return B.createStructExtract(beforeInst->getLoc(), val, SEI->getField(),
-                                 SEI->getType().getObjectType());
-  }
-  if (auto *TEI = dyn_cast<TupleElementAddrInst>(addr)) {
-    assert(ProjectionIndex(TEI).Index == elementIdx);
-    SILValue val = projectLoadValue(
-        TEI->getOperand(),
-        AccessPath(accessPath.getStorage(), pathNode.getParent(),
-                   accessPath.getOffset()),
-        rootVal, rootAccessPath, beforeInst);
-    SILBuilder B(beforeInst);
-    return B.createTupleExtract(beforeInst->getLoc(), val, TEI->getFieldIndex(),
-                                TEI->getType().getObjectType());
-  }
-  llvm_unreachable("unknown projection");
-}
-
-/// Returns true if all stores to \p addr commonly dominate the loop exits.
-static bool
-storesCommonlyDominateLoopExits(AccessPath accessPath,
-                                SILLoop *loop,
-                                ArrayRef<SILBasicBlock *> exitingBlocks) {
-  BasicBlockSet stores(loop->getHeader()->getParent());
-  SmallVector<Operand *, 8> uses;
-  // Collect as many recognizable stores as possible. It's ok if not all stores
-  // are collected.
-  accessPath.collectUses(uses, AccessUseType::Exact, loop->getFunction());
-  for (Operand *use : uses) {
-    SILInstruction *user = use->getUser();
-    if (isa<StoreInst>(user))
-      stores.insert(user->getParent());
-  }
-  SILBasicBlock *header = loop->getHeader();
-  // If a store is in the loop header, we already know that it's dominating all
-  // loop exits.
-  if (stores.contains(header))
-    return true;
-
-  // Also a store in the pre-header dominates all exists. Although the situation
-  // is a bit different here: the store in the pre-header remains - it's not
-  // (re)moved by the LICM transformation.
-  // But even if the loop-stores are not dominating the loop exits, it
-  // makes sense to move them out of the loop if this case. When this is done,
-  // dead-store-elimination can then most likely eliminate the store in the
-  // pre-header.
-  //
-  //   pre_header:
-  //     store %v1 to %addr
-  //   header:
-  //     cond_br %cond, then, tail
-  //   then:
-  //     store %v2 to %addr    // a conditional store in the loop
-  //     br tail
-  //   tail:
-  //     cond_br %loop_cond, header, exit
-  //   exit:
-  //
-  //  will be transformed to
-  //
-  //   pre_header:
-  //     store %v1 to %addr    // <- can be removed by DSE afterwards
-  //   header:
-  //     cond_br %cond, then, tail
-  //   then:
-  //     br tail
-  //   tail(%phi):
-  //     cond_br %loop_cond, header, exit
-  //   exit:
-  //     store %phi to %addr
-  //
-  if (stores.contains(loop->getLoopPreheader()))
-    return true;
-
-  // Propagate the store-is-not-alive flag through the control flow in the loop,
-  // starting at the header.
-  BasicBlockSet storesNotAlive(loop->getHeader()->getParent());
-  storesNotAlive.insert(header);
-  bool changed = false;
-  do {
-    changed = false;
-    for (SILBasicBlock *block : loop->blocks()) {
-      bool storeAlive = !storesNotAlive.contains(block);
-      if (storeAlive && !stores.contains(block) &&
-          std::any_of(block->pred_begin(), block->pred_end(),
-            [&](SILBasicBlock *b) { return storesNotAlive.contains(b); })) {
-        storesNotAlive.insert(block);
-        changed = true;
-      }
-    }
-  } while (changed);
-
-  auto isUnreachableBlock = [](SILBasicBlock *succ) {
-    return isa<UnreachableInst>(succ->getTerminator());
-  };
-
-  // Check if the store-is-not-alive flag reaches any of the exits.
-  for (SILBasicBlock *eb : exitingBlocks) {
-    // Ignore loop exits to blocks which end in an unreachable.
-    if (!std::any_of(eb->succ_begin(), eb->succ_end(), isUnreachableBlock) &&
-        storesNotAlive.contains(eb)) {
-      return false;
-    }
-  }
-  return true;
-}
-
-void LoopTreeOptimization::
-hoistLoadsAndStores(AccessPath accessPath, SILLoop *loop) {
-  SmallVector<SILBasicBlock *, 4> exitingAndLatchBlocks;
-  loop->getExitingAndLatchBlocks(exitingAndLatchBlocks);
-
-  // This is not a requirement for functional correctness, but we don't want to
-  // _speculatively_ load and store the value (outside of the loop).
-  if (!storesCommonlyDominateLoopExits(accessPath, loop,
-                                       exitingAndLatchBlocks))
-    return;
-
-  // Inserting the stores requires the exit edges to be not critical.
-  for (SILBasicBlock *exitingOrLatchBlock : exitingAndLatchBlocks) {
-    for (unsigned idx = 0, e = exitingOrLatchBlock->getSuccessors().size();
-         idx != e; ++idx) {
-      // exitingBlock->getSuccessors() must not be moved out of this loop,
-      // because the successor list is invalidated by splitCriticalEdge.
-      if (!loop->contains(exitingOrLatchBlock->getSuccessors()[idx])) {
-        splitCriticalEdge(exitingOrLatchBlock->getTerminator(), idx, DomTree,
-                          LoopInfo);
-      }
-    }
-  }
-
-  SILBasicBlock *preheader = loop->getLoopPreheader();
-  assert(preheader && "Expected a preheader");
-
-  // Initially load the value in the loop pre header.
-  SILBuilder B(preheader->getTerminator());
-  SILValue storeAddr;
-  SILSSAUpdater ssaUpdater;
-
-  // Set all stored values as available values in the ssaUpdater.
-  // If there are multiple stores in a block, only the last one counts.
-  std::optional<SILLocation> loc;
-  for (SILInstruction *I : LoadsAndStores) {
-    if (auto *SI = isStoreToAccess(I, accessPath)) {
-      loc = SI->getLoc();
-
-      // If a store just stores the loaded value, bail. The operand (= the load)
-      // will be removed later, so it cannot be used as available value.
-      // This corner case is surprisingly hard to handle, so we just give up.
-      if (isLoadWithinAccess(dyn_cast<LoadInst>(SI->getSrc()), accessPath))
-        return;
-
-      if (!storeAddr) {
-        storeAddr = SI->getDest();
-        ssaUpdater.initialize(storeAddr->getFunction(),
-                              storeAddr->getType().getObjectType(),
-                              storeAddr->getOwnershipKind());
-      } else if (SI->getDest()->getType() != storeAddr->getType()) {
-        // This transformation assumes that the values of all stores in the loop
-        // must be interchangeable. It won't work if stores different types
-        // because of casting or payload extraction even though they have the
-        // same access path.
-        return;
-      }
-      ssaUpdater.addAvailableValue(SI->getParent(), SI->getSrc());
-    }
-  }
-  assert(storeAddr && "hoistLoadsAndStores requires a store in the loop");
-  auto checkBase = [&](SILValue srcAddr) {
-    // Clone projections until the address dominates preheader.
-    if (DomTree->dominates(srcAddr->getParentBlock(), preheader))
-      return srcAddr;
-
-    // return an invalid SILValue to continue cloning.
-    return SILValue();
-  };
-  SILValue initialAddr =
-      cloneUseDefChain(storeAddr, preheader->getTerminator(), checkBase);
-  // cloneUseDefChain may currently fail if a begin_borrow or mark_dependence is
-  // in the chain.
-  if (!initialAddr)
-    return;
-
-  LoadOwnershipQualifier ownership = B.getFunction().hasOwnership() ?
-      LoadOwnershipQualifier::Trivial :
-      LoadOwnershipQualifier::Unqualified;
-
-  LoadInst *initialLoad =
-      B.createLoad(RegularLocation::getAutoGeneratedLocation(), initialAddr,
-                   ownership);
-  LLVM_DEBUG(llvm::dbgs() << "Creating preload " << *initialLoad);
-  ssaUpdater.addAvailableValue(preheader, initialLoad);
-
-  // Remove all stores and replace the loads with the current value.
-  SILBasicBlock *currentBlock = nullptr;
-  SILValue currentVal;
-  for (SILInstruction *I : LoadsAndStores) {
-    SILBasicBlock *block = I->getParent();
-    if (block != currentBlock) {
-      currentBlock = block;
-      currentVal = SILValue();
-    }
-    if (auto *SI = isStoreToAccess(I, accessPath)) {
-      LLVM_DEBUG(llvm::dbgs() << "Deleting reloaded store " << *SI);
-      currentVal = SI->getSrc();
-      toDelete.insert(SI);
-      continue;
-    }
-    auto loadWithAccess = isLoadWithinAccess(I, accessPath);
-    if (!loadWithAccess) {
-      continue;
-    }
-    // If we didn't see a store in this block yet, get the current value from
-    // the ssaUpdater.
-    if (!currentVal)
-      currentVal = ssaUpdater.getValueInMiddleOfBlock(block);
-
-    LoadInst *load = loadWithAccess.li;
-    auto loadAddress = load->getOperand();
-    SILValue projectedValue = projectLoadValue(
-        loadAddress, loadWithAccess.accessPath, currentVal, accessPath, load);
-    LLVM_DEBUG(llvm::dbgs() << "Replacing stored load " << *load << " with "
-                            << projectedValue);
-    load->replaceAllUsesWith(projectedValue);
-    toDelete.insert(load);
-  }
-
-  // Store back the value at all loop exits.
-  for (SILBasicBlock *exitingOrLatchBlock : exitingAndLatchBlocks) {
-    for (SILBasicBlock *succ : exitingOrLatchBlock->getSuccessors()) {
-      if (loop->contains(succ))
-        continue;
-
-      assert(succ->getSinglePredecessorBlock()
-             && "should have split critical edges");
-      SILBuilder B(succ->begin());
-      StoreOwnershipQualifier ownership = B.getFunction().hasOwnership() ?
-          StoreOwnershipQualifier::Trivial :
-          StoreOwnershipQualifier::Unqualified;
-      auto *SI = B.createStore(
-          loc.value(), ssaUpdater.getValueInMiddleOfBlock(succ), initialAddr,
-          ownership);
-      (void)SI;
-      LLVM_DEBUG(llvm::dbgs() << "Creating loop-exit store " << *SI);
-    }
-  }
-
-  // In case the value is only stored but never loaded in the loop.
-  eliminateDeadInstruction(initialLoad);
-}
-
-bool LoopTreeOptimization::hoistAllLoadsAndStores(SILLoop *loop) {
-  for (AccessPath accessPath : LoadAndStoreAddrs) {
-    hoistLoadsAndStores(accessPath, loop);
-  }
-  LoadsAndStores.clear();
-  LoadAndStoreAddrs.clear();
-
-  if (toDelete.empty())
-    return false;
-
-  for (SILInstruction *I : toDelete) {
-    recursivelyDeleteTriviallyDeadInstructions(I, /*force*/ true);
-  }
-  toDelete.clear();
-  return true;
-}
-
-namespace {
-/// Hoist loop invariant code out of innermost loops.
-///
-/// Transforms are identified by type, not instance. Split this
-/// Into two types: "High-level Loop Invariant Code Motion"
-/// and "Loop Invariant Code Motion".
-class LICM : public SILFunctionTransform {
-
-public:
-  LICM(bool RunsOnHighLevelSil) : RunsOnHighLevelSil(RunsOnHighLevelSil) {}
-
-  /// True if LICM is done on high-level SIL, i.e. semantic calls are not
-  /// inlined yet. In this case some semantic calls can be hoisted.
-  /// We only hoist semantic calls on high-level SIL because we can be sure that
-  /// e.g. an Array as SILValue is really immutable (including its content).
-  bool RunsOnHighLevelSil;
-
-  void run() override {
-    SILFunction *F = getFunction();
-
-    SILLoopAnalysis *LA = PM->getAnalysis<SILLoopAnalysis>();
-    SILLoopInfo *LoopInfo = LA->get(F);
-
-    if (LoopInfo->empty()) {
-      LLVM_DEBUG(llvm::dbgs() << "No loops in " << F->getName() << "\n");
-      return;
-    }
-
-    DominanceAnalysis *DA = PM->getAnalysis<DominanceAnalysis>();
-    PostDominanceAnalysis *PDA = PM->getAnalysis<PostDominanceAnalysis>();
-    AliasAnalysis *AA = PM->getAnalysis<AliasAnalysis>(F);
-    BasicCalleeAnalysis *BCA = PM->getAnalysis<BasicCalleeAnalysis>();
-    AccessStorageAnalysis *ASA = getAnalysis<AccessStorageAnalysis>();
-    DominanceInfo *DomTree = nullptr;
-
-    LLVM_DEBUG(llvm::dbgs() << "Processing loops in " << F->getName() << "\n");
-    bool Changed = false;
-
-    for (auto *TopLevelLoop : *LoopInfo) {
-      if (!DomTree) DomTree = DA->get(F);
-      LoopTreeOptimization Opt(TopLevelLoop, LoopInfo, AA, BCA, DomTree, PDA,
-                               ASA, RunsOnHighLevelSil);
-      Changed |= Opt.optimize();
-    }
-
-    if (Changed) {
-      LA->lockInvalidation();
-      DA->lockInvalidation();
-      PM->invalidateAnalysis(F, SILAnalysis::InvalidationKind::FunctionBody);
-      LA->unlockInvalidation();
-      DA->unlockInvalidation();
-    }
-  }
-};
-} // end anonymous namespace
-
-SILTransform *swift::createLICM() {
-  return new LICM(false);
-}
-
-SILTransform *swift::createHighLevelLICM() {
-  return new LICM(true);
-}
diff --git a/lib/SILOptimizer/LoopTransforms/LoopRotate.cpp b/lib/SILOptimizer/LoopTransforms/LoopRotate.cpp
index f89863a9ff0b5..ee0e47c56d303 100644
--- a/lib/SILOptimizer/LoopTransforms/LoopRotate.cpp
+++ b/lib/SILOptimizer/LoopTransforms/LoopRotate.cpp
@@ -428,7 +428,11 @@ static bool rotateLoop(SILLoop *loop, DominanceInfo *domInfo,
 
   for (auto &inst : *header) {
     if (auto *bfi = dyn_cast<BorrowedFromInst>(&inst)) {
-      valueMap[bfi] = valueMap[bfi->getBorrowedValue()];
+      // Don't do valueMap[bfi] = valueMap[bfi->getBorrowedValue()]
+      // The subscript operator returns a reference into the map. Due to the
+      // assignment the map might get "reallocated" from under us.
+      auto mappedValue = valueMap[bfi->getBorrowedValue()];
+      valueMap[bfi] = mappedValue;
     } else if (SILInstruction *cloned = inst.clone(preheaderBranch)) {
       mapOperands(cloned, valueMap);
 
@@ -485,6 +489,12 @@ namespace {
 class LoopRotation : public SILFunctionTransform {
 
   void run() override {
+#ifndef SWIFT_ENABLE_SWIFT_IN_SWIFT
+    // This pass results in verification failures when Swift sources are not
+    // enabled.
+    LLVM_DEBUG(llvm::dbgs() << "Loop Rotate disabled in C++-only Swift compiler\n");
+    return;
+#endif // !SWIFT_ENABLE_SWIFT_IN_SWIFT
     SILFunction *f = getFunction();
     SILLoopAnalysis *loopAnalysis = PM->getAnalysis<SILLoopAnalysis>();
     DominanceAnalysis *domAnalysis = PM->getAnalysis<DominanceAnalysis>();
diff --git a/lib/SILOptimizer/LoopTransforms/LoopUnroll.cpp b/lib/SILOptimizer/LoopTransforms/LoopUnroll.cpp
index cf8c61a3b8547..19846a9687dc1 100644
--- a/lib/SILOptimizer/LoopTransforms/LoopUnroll.cpp
+++ b/lib/SILOptimizer/LoopTransforms/LoopUnroll.cpp
@@ -19,6 +19,7 @@
 #include "swift/SIL/SILCloner.h"
 #include "swift/SILOptimizer/Analysis/LoopAnalysis.h"
 #include "swift/SILOptimizer/Analysis/IsSelfRecursiveAnalysis.h"
+#include "swift/SILOptimizer/Analysis/DeadEndBlocksAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Passes.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/BasicBlockOptUtils.h"
@@ -211,7 +212,8 @@ static std::optional<uint64_t> getMaxLoopTripCount(SILLoop *Loop,
 /// heuristic that looks at the trip count and the cost of the instructions in
 /// the loop to determine whether we should unroll this loop.
 static bool canAndShouldUnrollLoop(SILLoop *Loop, uint64_t TripCount,
-                                   IsSelfRecursiveAnalysis *SRA) {
+                                   IsSelfRecursiveAnalysis *SRA,
+                                   DeadEndBlocks *deb) {
   assert(Loop->getSubLoops().empty() && "Expect innermost loops");
   if (TripCount > 32)
     return false;
@@ -227,7 +229,7 @@ static bool canAndShouldUnrollLoop(SILLoop *Loop, uint64_t TripCount,
     (Loop->getBlocks())[0]->getParent()->getModule().getOptions().UnrollThreshold;
   for (auto *BB : Loop->getBlocks()) {
     for (auto &Inst : *BB) {
-      if (!canDuplicateLoopInstruction(Loop, &Inst))
+      if (!canDuplicateLoopInstruction(Loop, &Inst, deb))
         return false;
       if (instructionInlineCost(Inst) != InlineCost::Free)
         ++Cost;
@@ -388,7 +390,7 @@ updateSSA(SILFunction *Fn, SILLoop *Loop,
 
 /// Try to fully unroll the loop if we can determine the trip count and the trip
 /// count is below a threshold.
-static bool tryToUnrollLoop(SILLoop *Loop, IsSelfRecursiveAnalysis *SRA) {
+static bool tryToUnrollLoop(SILLoop *Loop, IsSelfRecursiveAnalysis *SRA, DeadEndBlocks *deb) {
   assert(Loop->getSubLoops().empty() && "Expecting innermost loops");
 
   LLVM_DEBUG(llvm::dbgs() << "Trying to unroll loop : \n" << *Loop);
@@ -409,7 +411,7 @@ static bool tryToUnrollLoop(SILLoop *Loop, IsSelfRecursiveAnalysis *SRA) {
     return false;
   }
 
-  if (!canAndShouldUnrollLoop(Loop, MaxTripCount.value(), SRA)) {
+  if (!canAndShouldUnrollLoop(Loop, MaxTripCount.value(), SRA, deb)) {
     LLVM_DEBUG(llvm::dbgs() << "Not unrolling, exceeds cost threshold\n");
     return false;
   }
@@ -490,6 +492,7 @@ class LoopUnrolling : public SILFunctionTransform {
     auto *Fun = getFunction();
     SILLoopInfo *LoopInfo = PM->getAnalysis<SILLoopAnalysis>()->get(Fun);
     IsSelfRecursiveAnalysis *SRA = PM->getAnalysis<IsSelfRecursiveAnalysis>();
+    DeadEndBlocks *deb = PM->getAnalysis<DeadEndBlocksAnalysis>()->get(Fun);
 
     LLVM_DEBUG(llvm::dbgs() << "Loop Unroll running on function : "
                             << Fun->getName() << "\n");
@@ -517,7 +520,7 @@ class LoopUnrolling : public SILFunctionTransform {
 
     // Try to unroll innermost loops.
     for (auto *Loop : InnermostLoops)
-      Changed |= tryToUnrollLoop(Loop, SRA);
+      Changed |= tryToUnrollLoop(Loop, SRA, deb);
 
     if (Changed) {
       invalidateAnalysis(SILAnalysis::InvalidationKind::FunctionBody);
diff --git a/lib/SILOptimizer/Mandatory/AccessEnforcementSelection.cpp b/lib/SILOptimizer/Mandatory/AccessEnforcementSelection.cpp
index 521508d4669cf..aa9ce8cb4f54f 100644
--- a/lib/SILOptimizer/Mandatory/AccessEnforcementSelection.cpp
+++ b/lib/SILOptimizer/Mandatory/AccessEnforcementSelection.cpp
@@ -285,7 +285,6 @@ static void checkUsesOfAccess(BeginAccessInst *access) {
     auto user = use->getUser();
     assert(!isa<BeginAccessInst>(user));
     assert(!isa<PartialApplyInst>(user) ||
-           onlyUsedByAssignByWrapper(cast<PartialApplyInst>(user)) ||
            onlyUsedByAssignOrInit(cast<PartialApplyInst>(user)));
   }
 #endif
diff --git a/lib/SILOptimizer/Mandatory/AddressLowering.cpp b/lib/SILOptimizer/Mandatory/AddressLowering.cpp
index 93b1a0613684c..90cec4ba14663 100644
--- a/lib/SILOptimizer/Mandatory/AddressLowering.cpp
+++ b/lib/SILOptimizer/Mandatory/AddressLowering.cpp
@@ -165,6 +165,8 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 
+#include <complex>
+
 using namespace swift;
 using llvm::SmallSetVector;
 
@@ -241,7 +243,13 @@ visitCallResults(FullApplySite apply,
   if (auto *destructure = getCallDestructure(apply)) {
     return visitCallMultiResults(destructure, fnConv, visitor);
   }
-  return visitor(apply.getResult(), *fnConv.getDirectSILResults().begin());
+  // Visit the single direct result, if any.
+  auto directResults = fnConv.getDirectSILResults();
+  if (!directResults.empty()) {
+    assert(std::distance(directResults.begin(), directResults.end()) == 1);
+    return visitor(apply.getResult(), *directResults.begin());
+  }
+  return true;
 }
 
 /// Return true if the given value is either a "fake" tuple that represents all
@@ -683,8 +691,9 @@ static void convertDirectToIndirectFunctionArgs(AddressLoweringState &pass) {
 }
 
 /// Before populating the ValueStorageMap, insert function arguments for any
-/// @out result type. Return the number of indirect result arguments added.
-static unsigned insertIndirectReturnArgs(AddressLoweringState &pass) {
+/// @out result type or @error_indirect.
+/// \returns the number of indirect result and error arguments added.
+static unsigned insertIndirectReturnOrErrorArgs(AddressLoweringState &pass) {
   auto &astCtx = pass.getModule()->getASTContext();
   auto typeCtx = pass.function->getTypeExpansionContext();
   auto *declCtx = pass.function->getDeclContext();
@@ -695,14 +704,14 @@ static unsigned insertIndirectReturnArgs(AddressLoweringState &pass) {
     declCtx = pass.function->getModule().getSwiftModule();
   }
 
-  unsigned argIdx = 0;
-  for (auto resultTy : pass.loweredFnConv.getIndirectSILResultTypes(typeCtx)) {
+  auto createIndirectResult = [&](SILType resultTy, StringRef internalName,
+                                  unsigned argIdx) {
     auto resultTyInContext = pass.function->mapTypeIntoContext(resultTy);
     auto bodyResultTy = pass.function->getModule().Types.getLoweredType(
         resultTyInContext.getASTType(), *pass.function);
-    auto var = new (astCtx) ParamDecl(
-        SourceLoc(), SourceLoc(), astCtx.getIdentifier("$return_value"),
-        SourceLoc(), astCtx.getIdentifier("$return_value"), declCtx);
+    auto var = new (astCtx)
+        ParamDecl(SourceLoc(), SourceLoc(), astCtx.getIdentifier(internalName),
+                  SourceLoc(), astCtx.getIdentifier(internalName), declCtx);
     var->setSpecifier(ParamSpecifier::InOut);
 
     SILFunctionArgument *funcArg =
@@ -713,10 +722,22 @@ static unsigned insertIndirectReturnArgs(AddressLoweringState &pass) {
     //
     // This is the only case where a value defines its own storage.
     pass.valueStorageMap.insertValue(funcArg, funcArg);
+  };
+
+  unsigned argIdx = 0;
+  for (auto resultTy : pass.loweredFnConv.getIndirectSILResultTypes(typeCtx))
+    createIndirectResult(resultTy, "$return_value", argIdx++);
 
-    ++argIdx;
-  }
   assert(argIdx == pass.loweredFnConv.getNumIndirectSILResults());
+
+  // Next, add the indirect error result, if needed.
+  // This must happen after all indirect result types have been added, to match
+  // the convention.
+  if (auto errorTy = pass.loweredFnConv.getIndirectErrorResultType(typeCtx))
+    createIndirectResult(errorTy, "$error", argIdx++);
+
+  assert(argIdx == pass.loweredFnConv.getNumIndirectSILResults() +
+                       pass.loweredFnConv.getNumIndirectSILErrorResults());
   return argIdx;
 }
 
@@ -907,8 +928,8 @@ static void prepareValueStorage(AddressLoweringState &pass) {
   // Fixup this function's argument types with temporary loads.
   convertDirectToIndirectFunctionArgs(pass);
 
-  // Create a new function argument for each indirect result.
-  insertIndirectReturnArgs(pass);
+  // Create a new function argument for each indirect result or error.
+  insertIndirectReturnOrErrorArgs(pass);
 
   // Populate valueStorageMap.
   OpaqueValueVisitor(pass).mapValueStorage();
@@ -2348,16 +2369,36 @@ class ApplyRewriter {
     return bb->begin();
   }
 
+  SILBasicBlock::iterator getErrorInsertionPoint() {
+    switch (apply.getKind()) {
+      case FullApplySiteKind::ApplyInst:
+      case FullApplySiteKind::BeginApplyInst:
+        llvm_unreachable("no error block exists for these instructions");
+
+      case FullApplySiteKind::TryApplyInst:
+        return cast<TryApplyInst>(apply)->getErrorBB()->begin();
+    }
+  }
+
   void makeIndirectArgs(MutableArrayRef<SILValue> newCallArgs);
 
   SILBasicBlock::iterator getResultInsertionPoint();
 
-  SILValue materializeIndirectResultAddress(SILValue oldResult, SILType argTy);
+  /// Indicator for the kind of output value from apply instructions.
+  enum class ApplyOutput {
+    Result,  // A returned value
+    Error    // A thrown error
+  };
+
+  SILValue materializeIndirectOutputAddress(ApplyOutput kind,
+                                            SILValue oldResult, SILType argTy);
 
   void rewriteApply(ArrayRef<SILValue> newCallArgs);
 
   void rewriteTryApply(ArrayRef<SILValue> newCallArgs);
 
+  void replaceBlockArg(SILArgument *arg, SILType newType, SILValue repl);
+
   void replaceDirectResults(DestructureTupleInst *oldDestructure);
 };
 } // end anonymous namespace
@@ -2510,7 +2551,8 @@ void ApplyRewriter::makeIndirectArgs(MutableArrayRef<SILValue> newCallArgs) {
            "canonical call results are always direct");
 
     if (loweredCalleeConv.isSILIndirect(resultInfo)) {
-      SILValue indirectResultAddr = materializeIndirectResultAddress(
+      SILValue indirectResultAddr = materializeIndirectOutputAddress(
+          ApplyOutput::Result,
           result, loweredCalleeConv.getSILType(resultInfo, typeCtx));
       // Record the new indirect call argument.
       newCallArgs[newResultArgIdx++] = indirectResultAddr;
@@ -2519,6 +2561,18 @@ void ApplyRewriter::makeIndirectArgs(MutableArrayRef<SILValue> newCallArgs) {
   };
   visitCallResults(apply, visitCallResult);
 
+  // Handle a try_apply for @error_indirect, who in the opaque convention has
+  // a direct error result, but needs an indirect error result when lowered.
+  if (auto errResult = apply.getDirectErrorResult()) {
+    if (auto errorInfo = loweredCalleeConv.getIndirectErrorResult()) {
+      SILValue indirectErrorAddr = materializeIndirectOutputAddress(
+          ApplyOutput::Error,
+          errResult, loweredCalleeConv.getSILType(*errorInfo, typeCtx));
+      // Record the new indirect call argument.
+      newCallArgs[newResultArgIdx++] = indirectErrorAddr;
+    }
+  }
+
   // Append the existing call arguments to the SIL argument list. They were
   // already lowered to addresses by CallArgRewriter.
   assert(newResultArgIdx == loweredCalleeConv.getSILArgIndexOfFirstParam());
@@ -2544,13 +2598,16 @@ SILBasicBlock::iterator ApplyRewriter::getResultInsertionPoint() {
   }
 }
 
-/// Return the storage address for the indirect result corresponding to the
+/// Return the storage address for the indirect output corresponding to the
 /// \p oldResult. Allocate temporary argument storage for an
-/// indirect result that isn't mapped to storage because it is either loadable
+/// indirect output that isn't mapped to storage because it is either loadable
 /// or unused.
 ///
 /// \p oldResult is invalid for an unused result.
-SILValue ApplyRewriter::materializeIndirectResultAddress(SILValue oldResult,
+///
+/// \param kind is the kind of output we're materializing an address for.
+SILValue ApplyRewriter::materializeIndirectOutputAddress(ApplyOutput kind,
+                                                         SILValue oldResult,
                                                          SILType argTy) {
   if (oldResult && oldResult->getType().isAddressOnly(*pass.function)) {
     // Results that project into their uses have not yet been materialized.
@@ -2573,7 +2630,10 @@ SILValue ApplyRewriter::materializeIndirectResultAddress(SILValue oldResult,
   if (oldResult && !oldResult->use_empty()) {
     // Insert reloads immediately after the call. Get the reload insertion
     // point after emitting dealloc to ensure the reload happens first.
-    auto reloadBuilder = pass.getBuilder(getResultInsertionPoint());
+    auto insertionPt = kind == ApplyOutput::Result
+                           ? getResultInsertionPoint()
+                           : getErrorInsertionPoint();
+    auto reloadBuilder = pass.getBuilder(insertionPt);
 
     // This is a formally indirect argument, but is loadable.
     auto *loadInst = reloadBuilder.createTrivialLoadOr(
@@ -2694,6 +2754,22 @@ void ApplyRewriter::convertBeginApplyWithOpaqueYield() {
   }
 }
 
+/// Utility to replace all uses of a block's argument with a SILValue,
+/// preserving the argument by creating a fresh, unused argument of the given
+/// type.
+///
+/// \param arg the block argument to be replaced
+/// \param newType the type of the fresh block argument to be created
+/// \param repl the value to replace uses of the old argument with
+void ApplyRewriter::replaceBlockArg(SILArgument *arg, SILType newType,
+                                    SILValue repl) {
+  const unsigned idx = arg->getIndex();
+  auto ownership = newType.isTrivial(*pass.function) ? OwnershipKind::None
+                                                     : OwnershipKind::Owned;
+  arg->replaceAllUsesWith(repl);
+  arg->getParent()->replacePhiArgument(idx, newType, ownership, arg->getDecl());
+}
+
 // Replace \p tryApply with a new try_apply using \p newCallArgs.
 //
 // If the old result was a single opaque value, then create and return a
@@ -2758,7 +2834,37 @@ void ApplyRewriter::convertBeginApplyWithOpaqueYield() {
 //   // no uses of %d1
 //
 void ApplyRewriter::rewriteTryApply(ArrayRef<SILValue> newCallArgs) {
-  auto typeCtx = pass.function->getTypeExpansionContext();
+  // Util to rewrite the argument to one of the successor blocks of a try_apply.
+  auto rewriteTryApplySuccBlockArg = [&](SILArgument *arg, SILType newArgTy,
+                                         SILBuilder &builder) {
+    assert(arg);
+    assert(arg->getIndex() == 0);
+
+    // Handle a single opaque result value.
+    if (pass.valueStorageMap.contains(arg)) {
+      // Storage was materialized by materializeIndirectOutputAddress.
+      auto &origStorage = pass.valueStorageMap.getStorage(arg);
+      assert(origStorage.isRewritten);
+      (void)origStorage;
+
+      // Rewriting try_apply with a new function type requires erasing the opaque
+      // block argument.  Create a dummy load-copy until all uses have been
+      // rewritten.
+      LoadInst *loadArg = builder.createLoad(
+          callLoc, origStorage.storageAddress, LoadOwnershipQualifier::Copy);
+
+      pass.valueStorageMap.replaceValue(arg, loadArg);
+      replaceBlockArg(arg, newArgTy, loadArg);
+      return;
+    }
+    // Loadable results were loaded by materializeIndirectOutputAddress.
+    // Temporarily redirect all uses to Undef. They will be fixed in
+    // replaceDirectResults().
+    auto undefVal =
+        SILUndef::get(pass.function, arg->getType().getAddressType());
+    replaceBlockArg(arg, newArgTy, undefVal);
+  };
+
   auto *tryApply = cast<TryApplyInst>(apply.getInstruction());
 
   auto *newCallInst = argBuilder.createTryApply(
@@ -2766,45 +2872,37 @@ void ApplyRewriter::rewriteTryApply(ArrayRef<SILValue> newCallArgs) {
       tryApply->getNormalBB(), tryApply->getErrorBB(),
       tryApply->getApplyOptions(), tryApply->getSpecializationInfo());
 
-  auto *resultArg = cast<SILArgument>(apply.getResult());
-
-  auto replaceTermResult = [&](SILValue newResultVal) {
-    SILType resultTy = loweredCalleeConv.getSILResultType(typeCtx);
-    auto ownership = resultTy.isTrivial(*pass.function) ? OwnershipKind::None
-                                                        : OwnershipKind::Owned;
-
-    resultArg->replaceAllUsesWith(newResultVal);
-    assert(resultArg->getIndex() == 0);
-    resultArg->getParent()->replacePhiArgument(0, resultTy, ownership,
-                                               resultArg->getDecl());
-  };
   // Immediately delete the old try_apply (old applies hang around until
   // dead code removal because they directly define values).
   pass.deleter.forceDelete(tryApply);
   this->apply = FullApplySite(newCallInst);
 
-  // Handle a single opaque result value.
-  if (pass.valueStorageMap.contains(resultArg)) {
-    // Storage was materialized by materializeIndirectResultAddress.
-    auto &origStorage = pass.valueStorageMap.getStorage(resultArg);
-    assert(origStorage.isRewritten);
-    (void)origStorage;
-
-    // Rewriting try_apply with a new function type requires erasing the opaque
-    // block argument.  Create a dummy load-copy until all uses have been
-    // rewritten.
-    LoadInst *loadArg = resultBuilder.createLoad(
-        callLoc, origStorage.storageAddress, LoadOwnershipQualifier::Copy);
-
-    pass.valueStorageMap.replaceValue(resultArg, loadArg);
-    replaceTermResult(loadArg);
-    return;
+  auto typeCtx = pass.function->getTypeExpansionContext();
+  auto &astCtx = pass.getModule()->getASTContext();
+  auto calleeFnTy = apply.getSubstCalleeType();
+  SILArgument *resultArg = nullptr, *errorArg = nullptr;
+
+  if (calleeFnTy->hasIndirectFormalResults()) {
+    resultArg = cast<SILArgument>(apply.getResult());
+    SILType resultTy = loweredCalleeConv.getSILResultType(typeCtx);
+    rewriteTryApplySuccBlockArg(resultArg, resultTy, resultBuilder);
   }
-  // Loadable results were loaded by materializeIndirectResultAddress.
-  // Temporarily redirect all uses to Undef. They will be fixed in
-  // replaceDirectResults().
-  replaceTermResult(
-      SILUndef::get(pass.function, resultArg->getType().getAddressType()));
+
+  if (calleeFnTy->hasIndirectErrorResult()) {
+    errorArg = cast<SILArgument>(apply.getDirectErrorResult());
+    auto *errBB = errorArg->getParentBlock();
+    SILBuilder errorBuilder = pass.getBuilder(getErrorInsertionPoint());
+
+    // A made-up type, since we're going to delete the argument.
+    auto dummyTy = SILType::getEmptyTupleType(astCtx);
+    rewriteTryApplySuccBlockArg(errorArg, dummyTy, errorBuilder);
+
+    // We must delete the error block's argument for an @error_indirect
+    assert(errBB->getNumArguments() == 1);
+    errBB->eraseArgument(0);
+  }
+
+  assert((resultArg || errorArg) && "should have rewritten something?");
 }
 
 // Replace all formally direct results by rewriting the destructure_tuple.
@@ -2924,7 +3022,7 @@ class CheckedCastBrRewriter {
     }
 
     termBuilder.createCheckedCastAddrBranch(
-        castLoc, ccb->getIsolatedConformances(),
+        castLoc, ccb->getCheckedCastOptions(),
         CastConsumptionKind::TakeOnSuccess, srcAddr,
         ccb->getSourceFormalType(), destAddr, ccb->getTargetFormalType(),
         successBB, failureBB, ccb->getTrueBBCount(), ccb->getFalseBBCount());
@@ -3021,7 +3119,7 @@ static UnconditionalCheckedCastAddrInst *rewriteUnconditionalCheckedCastInst(
   }
   assert(destAddr);
   auto *uccai = builder.createUnconditionalCheckedCastAddr(
-      uncondCheckedCast->getLoc(), uncondCheckedCast->getIsolatedConformances(),
+      uncondCheckedCast->getLoc(), uncondCheckedCast->getCheckedCastOptions(),
       srcAddr, srcAddr->getType().getASTType(),
       destAddr, destAddr->getType().getASTType());
   auto afterBuilder =
@@ -3062,9 +3160,11 @@ class ReturnRewriter {
       : pass(pass), opaqueFnConv(pass.function->getConventions()) {}
 
   void rewriteReturns();
+  void rewriteThrows();
 
 protected:
   void rewriteReturn(ReturnInst *returnInst);
+  void rewriteThrow(ThrowInst *throwInst);
 
   void rewriteElement(SILValue oldResult, SILArgument *newResultArg,
                       SILBuilder &returnBuilder);
@@ -3079,18 +3179,42 @@ void ReturnRewriter::rewriteReturns() {
   }
 }
 
-void ReturnRewriter::rewriteReturn(ReturnInst *returnInst) {
-  auto &astCtx = pass.getModule()->getASTContext();
-  auto typeCtx = pass.function->getTypeExpansionContext();
+void ReturnRewriter::rewriteThrows() {
+  for (SILInstruction *termInst : pass.exitingInsts) {
+    if (auto *throwInst = dyn_cast<ThrowInst>(termInst))
+      rewriteThrow(throwInst);
+    else
+      assert(isa<ReturnInst>(termInst));
+  }
+}
 
-  // Find the point before allocated storage has been deallocated.
-  auto insertPt = SILBasicBlock::iterator(returnInst);
-  for (auto bbStart = returnInst->getParent()->begin(); insertPt != bbStart;
+// Find the point just before allocated storage has been deallocated,
+// immediately prior to this instruction.
+static SILBasicBlock::iterator beforeStorageDeallocs(SILInstruction *inst) {
+  auto insertPt = SILBasicBlock::iterator(inst);
+  for (auto bbStart = inst->getParent()->begin(); insertPt != bbStart;
        --insertPt) {
     if (!isa<DeallocStackInst>(*std::prev(insertPt)))
       break;
   }
-  auto returnBuilder = pass.getBuilder(insertPt);
+  return insertPt;
+}
+
+void ReturnRewriter::rewriteThrow(ThrowInst *throwInst) {
+  auto idx = pass.loweredFnConv.getArgumentIndexOfIndirectErrorResult();
+  SILArgument *errorResultAddr = pass.function->getArgument(idx.value());
+
+  auto throwBuilder = pass.getBuilder(beforeStorageDeallocs(throwInst));
+  rewriteElement(throwInst->getOperand(), errorResultAddr, throwBuilder);
+  throwBuilder.createThrowAddr(throwInst->getLoc());
+  pass.deleter.forceDelete(throwInst);
+}
+
+void ReturnRewriter::rewriteReturn(ReturnInst *returnInst) {
+  auto &astCtx = pass.getModule()->getASTContext();
+  auto typeCtx = pass.function->getTypeExpansionContext();
+
+  auto returnBuilder = pass.getBuilder(beforeStorageDeallocs(returnInst));
 
   // Gather direct function results.
   unsigned numOldResults = opaqueFnConv.getNumDirectSILResults();
@@ -3126,7 +3250,7 @@ void ReturnRewriter::rewriteReturn(ReturnInst *returnInst) {
 
   assert(newDirectResults.size() ==
          pass.loweredFnConv.getNumDirectSILResults());
-  assert(newResultArgIdx == pass.loweredFnConv.getSILArgIndexOfFirstParam());
+  assert(newResultArgIdx == pass.loweredFnConv.getNumIndirectSILResults());
 
   // Generate a new return_inst for the new direct results.
   SILValue newReturnVal;
@@ -3365,6 +3489,11 @@ class UseRewriter : SILInstructionVisitor<UseRewriter> {
     yield->setOperand(use->getOperandNumber(), addr);
   }
 
+  void visitIgnoredUseInst(IgnoredUseInst *ignored) {
+    SILValue addr = addrMat.materializeAddress(use->get());
+    ignored->setOperand(addr);
+  }
+
   void visitValueMetatypeInst(ValueMetatypeInst *vmi) {
     SILValue opAddr = addrMat.materializeAddress(use->get());
     vmi->setOperand(opAddr);
@@ -3527,6 +3656,11 @@ class UseRewriter : SILInstructionVisitor<UseRewriter> {
     // opaque value rewriting.
   }
 
+  void visitThrowInst(ThrowInst *throwInst) {
+    // Throws are rewritten for any function with an @error_indirect after
+    // opaque value rewriting.
+  }
+
   void visitStoreBorrowInst(StoreBorrowInst *sbi) {
     auto addr = addrMat.materializeAddress(use->get());
     SmallVector<Operand *, 4> uses(sbi->getUses());
@@ -4229,7 +4363,9 @@ static void rewriteIndirectApply(ApplySite anyApply,
   switch (apply.getKind()) {
   case FullApplySiteKind::ApplyInst:
   case FullApplySiteKind::TryApplyInst: {
-    if (!apply.getSubstCalleeType()->hasIndirectFormalResults()) {
+    auto calleeFnTy = apply.getSubstCalleeType();
+    if (!calleeFnTy->hasIndirectFormalResults() &&
+        !calleeFnTy->hasIndirectErrorResult()) {
       return;
     }
     // If the call has indirect results and wasn't already rewritten, rewrite it
@@ -4337,6 +4473,8 @@ static void rewriteFunction(AddressLoweringState &pass) {
     ReturnRewriter(pass).rewriteReturns();
   if (pass.function->getLoweredFunctionType()->hasIndirectFormalYields())
     YieldRewriter(pass).rewriteYields();
+  if (pass.function->getLoweredFunctionType()->hasIndirectErrorResult())
+    ReturnRewriter(pass).rewriteThrows();
 }
 
 // Given an array of terminator operand values, produce an array of
diff --git a/lib/SILOptimizer/Mandatory/ConsumeOperatorCopyableAddressesChecker.cpp b/lib/SILOptimizer/Mandatory/ConsumeOperatorCopyableAddressesChecker.cpp
index 882a543d1c58f..0210ccda903fb 100644
--- a/lib/SILOptimizer/Mandatory/ConsumeOperatorCopyableAddressesChecker.cpp
+++ b/lib/SILOptimizer/Mandatory/ConsumeOperatorCopyableAddressesChecker.cpp
@@ -163,8 +163,8 @@
 #include "swift/SILOptimizer/Analysis/LoopAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/CFGOptUtils.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstOptUtils.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "swift/SILOptimizer/Utils/SILOptFunctionBuilder.h"
 #include "swift/SILOptimizer/Utils/SpecializationMangler.h"
 #include "llvm/ADT/PointerEmbeddedInt.h"
@@ -1340,11 +1340,11 @@ bool GatherLexicalLifetimeUseVisitor::visitUse(Operand *op,
     return true;
   }
 
-  // Then see if we have a inout_aliasable full apply site use. In that case, we
-  // are going to try and extend move checking into the partial apply using
-  // cloning to eliminate destroys or reinits.
   if (auto fas = FullApplySite::isa(op->getUser())) {
-    if (stripAccessMarkers(op->get()) != useState.address) {
+    auto convention = fas.getCaptureConvention(*op);
+    // Bail on non-inout apply uses of fields.
+    if (convention != SILArgumentConvention::Indirect_Inout &&
+        stripAccessMarkers(op->get()) != useState.address) {
       LLVM_DEBUG(
           llvm::dbgs()
           << "!!! Error! Found consuming closure use not on base address: "
@@ -1352,8 +1352,10 @@ bool GatherLexicalLifetimeUseVisitor::visitUse(Operand *op,
       return false;
     }
 
-    if (fas.getCaptureConvention(*op) ==
-        SILArgumentConvention::Indirect_InoutAliasable) {
+    // Then see if we have an inout_aliasable full apply site use. In that case,
+    // we are going to try and extend move checking into the partial apply
+    // using cloning to eliminate destroys or reinits.
+    if (convention == SILArgumentConvention::Indirect_InoutAliasable) {
       // If we don't find the function, we can't handle this, so bail.
       auto *func = fas.getCalleeFunction();
       if (!func || !func->isDefer())
diff --git a/lib/SILOptimizer/Mandatory/ConsumeOperatorCopyableValuesChecker.cpp b/lib/SILOptimizer/Mandatory/ConsumeOperatorCopyableValuesChecker.cpp
index 3704d8a0a8c82..9d54e6633569f 100644
--- a/lib/SILOptimizer/Mandatory/ConsumeOperatorCopyableValuesChecker.cpp
+++ b/lib/SILOptimizer/Mandatory/ConsumeOperatorCopyableValuesChecker.cpp
@@ -33,7 +33,7 @@
 #include "swift/SILOptimizer/Analysis/LoopAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/CFGOptUtils.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 
 using namespace swift;
 
@@ -157,6 +157,11 @@ bool CheckerLivenessInfo::compute() {
               return false;
             }
           }
+        } else if (isa<StoreBorrowInst>(user)) {
+          if (liveness->updateForBorrowingOperand(use) !=
+              InnerBorrowKind::Contained) {
+            return false;
+          }
         }
         // FIXME: this ignores all other forms of Borrow ownership, such as
         // partial_apply [onstack] and mark_dependence [nonescaping].
@@ -222,7 +227,7 @@ struct ConsumeOperatorCopyableValuesChecker {
   CheckerLivenessInfo livenessInfo;
   DominanceInfo *dominance;
   InstructionDeleter deleter;
-  CanonicalizeOSSALifetime canonicalizer;
+  OSSACanonicalizeOwned canonicalizer;
 
   ConsumeOperatorCopyableValuesChecker(
       SILFunction *fn, DominanceInfo *dominance,
diff --git a/lib/SILOptimizer/Mandatory/DIMemoryUseCollector.cpp b/lib/SILOptimizer/Mandatory/DIMemoryUseCollector.cpp
index e0c7bcd63af6d..3ca1f6c06661c 100644
--- a/lib/SILOptimizer/Mandatory/DIMemoryUseCollector.cpp
+++ b/lib/SILOptimizer/Mandatory/DIMemoryUseCollector.cpp
@@ -578,7 +578,7 @@ bool DIMemoryUse::onlyTouchesTrivialElements(
     const DIMemoryObjectInfo &MI) const {
   // assign_by_wrapper calls functions to assign a value. This is not
   // considered as trivial.
-  if (isa<AssignByWrapperInst>(Inst) || isa<AssignOrInitInst>(Inst))
+  if (isa<AssignOrInitInst>(Inst))
     return false;
 
   auto *F = Inst->getFunction();
@@ -851,15 +851,14 @@ void ElementUseCollector::collectUses(SILValue Pointer, unsigned BaseEltNo) {
 #include "swift/AST/ReferenceStorage.def"
 
     // Stores *to* the allocation are writes.
-    if ((isa<StoreInst>(User) || isa<AssignInst>(User) ||
-         isa<AssignByWrapperInst>(User)) &&
+    if ((isa<StoreInst>(User) || isa<AssignInst>(User)) &&
         Op->getOperandNumber() == 1) {
       // Coming out of SILGen, we assume that raw stores are initializations,
       // unless they have trivial type (which we classify as InitOrAssign).
       DIUseKind Kind;
       if (InStructSubElement)
         Kind = DIUseKind::PartialStore;
-      else if (isa<AssignInst>(User) || isa<AssignByWrapperInst>(User))
+      else if (isa<AssignInst>(User))
         Kind = DIUseKind::InitOrAssign;
       else if (PointeeType.isTrivial(*User->getFunction()))
         Kind = DIUseKind::InitOrAssign;
@@ -1141,8 +1140,6 @@ void ElementUseCollector::collectUses(SILValue Pointer, unsigned BaseEltNo) {
     }
 
     if (auto *PAI = dyn_cast<PartialApplyInst>(User)) {
-      if (onlyUsedByAssignByWrapper(PAI))
-        continue;
 
       if (onlyUsedByAssignOrInit(PAI))
         continue;
@@ -1244,13 +1241,24 @@ ElementUseCollector::collectAssignOrInitUses(AssignOrInitInst *Inst,
   /// that the flag is dropped before calling \c addElementUses.
   llvm::SaveAndRestore<bool> X(IsSelfOfNonDelegatingInitializer, false);
 
-  auto *typeDC = Inst->getReferencedInitAccessor()
-                     ->getDeclContext()
-                     ->getSelfNominalTypeDecl();
+  NominalTypeDecl *typeDC = nullptr;
+  if (auto declContext = Inst->getDeclContextOrNull()->getSelfNominalTypeDecl())
+    typeDC = declContext;
 
   auto expansionContext = TypeExpansionContext(TheMemory.getFunction());
-
-  auto selfTy = Inst->getSelf()->getType();
+  auto selfOrLocalTy = Inst->getSelfOrLocalOperand()->getType();
+
+  if (!typeDC) {
+    // Local context: objTy holds the projection value for the backing storage
+    // local
+    auto objTy = selfOrLocalTy.getObjectType();
+    unsigned N =
+        getElementCountRec(expansionContext, Module, objTy, /*isSelf=*/false);
+    trackUse(DIMemoryUse(Inst, DIUseKind::InitOrAssign,
+                         /*firstEltRelToObj=*/BaseEltNo,
+                         /*NumElements=*/N));
+    return;
+  }
 
   auto addUse = [&](VarDecl *property, DIUseKind useKind) {
     unsigned fieldIdx = 0;
@@ -1260,15 +1268,14 @@ ElementUseCollector::collectAssignOrInitUses(AssignOrInitInst *Inst,
 
       fieldIdx += getElementCountRec(
           expansionContext, Module,
-          selfTy.getFieldType(VD, Module, expansionContext), false);
+          selfOrLocalTy.getFieldType(VD, Module, expansionContext), false);
     }
 
-    auto type = selfTy.getFieldType(property, Module, expansionContext);
+    auto type = selfOrLocalTy.getFieldType(property, Module, expansionContext);
     addElementUses(fieldIdx, type, Inst, useKind, property);
   };
 
-  auto initializedElts = Inst->getInitializedProperties();
-  if (initializedElts.empty()) {
+  if (Inst->getNumInitializedProperties() == 0) {
     auto initAccessorProperties = typeDC->getInitAccessorProperties();
     auto initFieldAt = typeDC->getStoredProperties().size();
 
@@ -1286,8 +1293,8 @@ ElementUseCollector::collectAssignOrInitUses(AssignOrInitInst *Inst,
       ++initFieldAt;
     }
   } else {
-    for (auto *property : initializedElts)
-      addUse(property, DIUseKind::InitOrAssign);
+    Inst->forEachInitializedProperty(
+        [&](VarDecl *property) { addUse(property, DIUseKind::InitOrAssign); });
   }
 
   for (auto *property : Inst->getAccessedProperties())
@@ -1704,8 +1711,6 @@ void ElementUseCollector::collectClassSelfUses(
     // If this is a partial application of self, then this is an escape point
     // for it.
     if (auto *PAI = dyn_cast<PartialApplyInst>(User)) {
-      if (onlyUsedByAssignByWrapper(PAI))
-        continue;
 
       if (onlyUsedByAssignOrInit(PAI))
         continue;
diff --git a/lib/SILOptimizer/Mandatory/DataflowDiagnostics.cpp b/lib/SILOptimizer/Mandatory/DataflowDiagnostics.cpp
index 5e161eb690350..ea8397a6fd295 100644
--- a/lib/SILOptimizer/Mandatory/DataflowDiagnostics.cpp
+++ b/lib/SILOptimizer/Mandatory/DataflowDiagnostics.cpp
@@ -69,10 +69,9 @@ static void diagnoseMissingReturn(const UnreachableInst *UI,
           Context.Diags.diagnose(expr->getStartLoc(),
                                  diag::missing_return_closure, ResTy);
         } else {
-          auto *DC = FLoc.getAsDeclContext();
-          assert(DC && DC->getAsDecl() && "not a declaration?");
+          auto *FD = FLoc.castToASTNode<AbstractFunctionDecl>();
           Context.Diags.diagnose(expr->getStartLoc(), diag::missing_return_decl,
-                                 ResTy, DC->getAsDecl()->getDescriptiveKind());
+                                 ResTy, FD);
         }
         Context.Diags
             .diagnose(expr->getStartLoc(), diag::missing_return_last_expr_note)
@@ -89,12 +88,10 @@ static void diagnoseMissingReturn(const UnreachableInst *UI,
                                : diag::missing_return_closure;
     diagnose(Context, L.getEndSourceLoc(), diagID, ResTy);
   } else {
-    auto *DC = FLoc.getAsDeclContext();
-    assert(DC && DC->getAsDecl() && "not a declaration?");
+    auto *FD = FLoc.castToASTNode<AbstractFunctionDecl>();
     auto diagID = isNoReturnFn ? diag::missing_never_call_decl
                                : diag::missing_return_decl;
-    diagnose(Context, L.getEndSourceLoc(), diagID, ResTy,
-             DC->getAsDecl()->getDescriptiveKind());
+    diagnose(Context, L.getEndSourceLoc(), diagID, ResTy, FD);
   }
 }
 
diff --git a/lib/SILOptimizer/Mandatory/DebugInfoCanonicalizer.cpp b/lib/SILOptimizer/Mandatory/DebugInfoCanonicalizer.cpp
index 13b9ab4e84367..ea21e01737af9 100644
--- a/lib/SILOptimizer/Mandatory/DebugInfoCanonicalizer.cpp
+++ b/lib/SILOptimizer/Mandatory/DebugInfoCanonicalizer.cpp
@@ -125,8 +125,8 @@ struct DebugInfoCanonicalizer {
       SILBasicBlock *startBlock,
       llvm::SmallDenseSet<SILDebugVariable, 8> &seenDebugVars) {
     LLVM_DEBUG(llvm::dbgs() << "==> PROPAGATING VALUE\n");
-    if (insertPt.is<SILInstruction *>()) {
-      LLVM_DEBUG(llvm::dbgs() << "Inst: " << *insertPt.get<SILInstruction *>());
+    if (isa<SILInstruction *>(insertPt)) {
+      LLVM_DEBUG(llvm::dbgs() << "Inst: " << *cast<SILInstruction *>(insertPt));
     }
 
     auto *dt = getDominance();
@@ -172,7 +172,7 @@ struct DebugInfoCanonicalizer {
         if (auto *inst = insertPt.dyn_cast<SILInstruction *>()) {
           cloneDebugValue(pred.second, inst);
         } else {
-          cloneDebugValue(pred.second, insertPt.get<SILBasicBlock *>());
+          cloneDebugValue(pred.second, cast<SILBasicBlock *>(insertPt));
         }
 
         madeChange = true;
diff --git a/lib/SILOptimizer/Mandatory/DefiniteInitialization.cpp b/lib/SILOptimizer/Mandatory/DefiniteInitialization.cpp
index a385a2475d442..4df93a776435e 100644
--- a/lib/SILOptimizer/Mandatory/DefiniteInitialization.cpp
+++ b/lib/SILOptimizer/Mandatory/DefiniteInitialization.cpp
@@ -688,8 +688,7 @@ bool LifetimeChecker::shouldEmitError(const SILInstruction *Inst) {
 
     if (auto *PAI = isOnlyUsedByPartialApply(load)) {
       if (std::find_if(PAI->use_begin(), PAI->use_end(), [](auto PAIUse) {
-            return isa<AssignByWrapperInst>(PAIUse->getUser()) ||
-                   isa<AssignOrInitInst>(PAIUse->getUser());
+            return isa<AssignOrInitInst>(PAIUse->getUser());
           }) != PAI->use_end()) {
         return false;
       }
@@ -1115,8 +1114,7 @@ void LifetimeChecker::injectActorHops() {
 
 void LifetimeChecker::doIt() {
   // With any escapes tallied up, we can work through all the uses, checking
-  // for definitive initialization, promoting loads, rewriting assigns, and
-  // performing other tasks.
+  // for definitive initialization and performing other tasks.
 
   // Note that this should not use a for-each loop, as the Uses list can grow
   // and reallocate as we iterate over it.
@@ -1186,7 +1184,7 @@ void LifetimeChecker::doIt() {
     }
   }
 
-  // If we emitted an error, there is no reason to proceed with load promotion.
+  // If we emitted an error, there is no reason to proceed.
   if (!EmittedErrorLocs.empty()) {
     // Since we failed DI, for now, turn off the move checker on the entire
     // function. With time, we should be able to allow for move checker checks
@@ -1579,8 +1577,6 @@ void LifetimeChecker::handleStoreUse(unsigned UseID) {
       addr = moveAddr->getDest();
     else if (auto *assign = dyn_cast<AssignInst>(inst))
       addr = assign->getDest();
-    else if (auto *assign = dyn_cast<AssignByWrapperInst>(inst))
-      addr = assign->getDest();
     else
       return false;
 
@@ -1637,13 +1633,6 @@ void LifetimeChecker::handleStoreUse(unsigned UseID) {
     } else {
       Use.Kind = DIUseKind::Initialization;
     }
-  } else if (isFullyInitialized && isa<AssignByWrapperInst>(Use.Inst)) {
-    // If some fields are uninitialized, re-write assign_by_wrapper to assignment
-    // of the backing wrapper. If all fields are initialized, assign to the wrapped
-    // value.
-    auto allFieldsInitialized =
-        getAnyUninitializedMemberAtInst(Use.Inst, 0, TheMemory.getNumElements()) == -1;
-    Use.Kind = allFieldsInitialized ? DIUseKind::Set : DIUseKind::Assign;
   } else if (isFullyInitialized && isa<AssignOrInitInst>(Use.Inst)) {
     auto allFieldsInitialized =
         getAnyUninitializedMemberAtInst(Use.Inst, 0,
@@ -1809,6 +1798,7 @@ void LifetimeChecker::handleInOutUse(const DIMemoryUse &Use) {
         case AccessorKind::Read:
         case AccessorKind::Read2:
         case AccessorKind::Address:
+        case AccessorKind::Borrow:
           return false;
         case AccessorKind::Set:
         case AccessorKind::Modify:
@@ -1817,6 +1807,7 @@ void LifetimeChecker::handleInOutUse(const DIMemoryUse &Use) {
         case AccessorKind::DidSet:
         case AccessorKind::WillSet:
         case AccessorKind::Init:
+        case AccessorKind::Mutate:
           return true;
         }
         llvm_unreachable("bad kind");
@@ -2486,8 +2477,7 @@ void LifetimeChecker::handleSelfInitUse(unsigned UseID) {
            "delegating inits have a single elt");
 
     // Lower Assign instructions if needed.
-    if (isa<AssignInst>(Use.Inst) || isa<AssignByWrapperInst>(Use.Inst) ||
-        isa<AssignOrInitInst>(Use.Inst))
+    if (isa<AssignInst>(Use.Inst) || isa<AssignOrInitInst>(Use.Inst))
       NeedsUpdateForInitState.push_back(UseID);
   } else {
     // super.init also requires that all ivars are initialized before the
@@ -2523,8 +2513,8 @@ static void setStaticInitAccess(SILValue memoryAddress) {
 
 /// updateInstructionForInitState - When an instruction being analyzed moves
 /// from being InitOrAssign to some concrete state, update it for that state.
-/// This includes rewriting them from assign instructions into their composite
-/// operations.
+/// This includes marking assign instructions so they will be appropriately
+/// handled during RawSILInstLowering.
 void LifetimeChecker::updateInstructionForInitState(unsigned UseID) {
   DIMemoryUse &Use = Uses[UseID];
   SILInstruction *Inst = Use.Inst;
@@ -2573,14 +2563,17 @@ void LifetimeChecker::updateInstructionForInitState(unsigned UseID) {
     return; \
   }
 #include "swift/AST/ReferenceStorage.def"
-  
-  // If this is an assign, rewrite it based on whether it is an initialization
-  // or not.
-  if (auto *AI = dyn_cast<AssignInst>(Inst)) {
-    // Remove this instruction from our data structures, since we will be
-    // removing it.
+
+  // Helper to remove the instruction from our data structures.
+  auto eraseUseInst = [&] {
     Use.Inst = nullptr;
     llvm::erase_if(NonLoadUses[Inst], [&](unsigned id) { return id == UseID; });
+  };
+
+  // If this is an assign, mark it so that RawSILInstLowering can handle it
+  // appropriately.
+  if (auto *AI = dyn_cast<AssignInst>(Inst)) {
+    eraseUseInst();
 
     if (TheMemory.isClassInitSelf() &&
         Use.Kind == DIUseKind::SelfInit) {
@@ -2614,10 +2607,7 @@ void LifetimeChecker::updateInstructionForInitState(unsigned UseID) {
   }
 
   if (auto *AI = dyn_cast<AssignOrInitInst>(Inst)) {
-    // Remove this instruction from our data structures, since we will be
-    // removing it.
-    Use.Inst = nullptr;
-    llvm::erase_if(NonLoadUses[Inst], [&](unsigned id) { return id == UseID; });
+    eraseUseInst();
 
     switch (Use.Kind) {
     case DIUseKind::Assign:
@@ -2636,29 +2626,6 @@ void LifetimeChecker::updateInstructionForInitState(unsigned UseID) {
     return;
   }
 
-  if (auto *AI = dyn_cast<AssignByWrapperInst>(Inst)) {
-    // Remove this instruction from our data structures, since we will be
-    // removing it.
-    Use.Inst = nullptr;
-    llvm::erase_if(NonLoadUses[Inst], [&](unsigned id) { return id == UseID; });
-
-    switch (Use.Kind) {
-    case DIUseKind::Initialization:
-      AI->setMode(AssignByWrapperInst::Initialization);
-      break;
-    case DIUseKind::Assign:
-      AI->setMode(AssignByWrapperInst::Assign);
-      break;
-    case DIUseKind::Set:
-      AI->setMode(AssignByWrapperInst::AssignWrappedValue);
-      break;
-    default:
-      llvm_unreachable("Wrong use kind for assign_by_wrapper");
-    }
-
-    return;
-  }
-
   if (auto *TACI = dyn_cast<TupleAddrConstructorInst>(Inst)) {
     assert(!TACI->isInitializationOfDest() &&
            "should not modify copy_addr that already knows it is initialized");
@@ -2976,7 +2943,8 @@ static SILValue testAllControlVariableBits(SILLocation Loc,
   if (IVType->getFixedWidth() == 1)
     return CondVal;
 
-  SILValue AllBitsSet = B.createIntegerLiteral(Loc, CondVal->getType(), -1);
+  SILValue AllBitsSet = B.createIntegerLiteral(Loc, CondVal->getType(), -1,
+                                               /*treatAsSigned=*/true);
   if (!CmpEqFn.get())
     CmpEqFn = getBinaryFunction("cmp_eq", CondVal->getType(),
                                 B.getASTContext());
@@ -3900,8 +3868,7 @@ static bool checkDefiniteInitialization(SILFunction &Fn) {
 
 namespace {
 
-/// Perform definitive initialization analysis and promote alloc_box uses into
-/// SSA registers for later SSA-based dataflow passes.
+/// Perform definitive initialization analysis.
 class DefiniteInitialization : public SILFunctionTransform {
   /// The entry point to the transformation.
   void run() override {
@@ -3909,7 +3876,6 @@ class DefiniteInitialization : public SILFunctionTransform {
     if (getFunction()->wasDeserializedCanonical())
       return;
 
-    // Walk through and promote all of the alloc_box's that we can.
     if (checkDefiniteInitialization(*getFunction())) {
       invalidateAnalysis(SILAnalysis::InvalidationKind::FunctionBody);
     }
diff --git a/lib/SILOptimizer/Mandatory/DiagnoseStaticExclusivity.cpp b/lib/SILOptimizer/Mandatory/DiagnoseStaticExclusivity.cpp
index 0913dd1cace1a..60388e39d7bc2 100644
--- a/lib/SILOptimizer/Mandatory/DiagnoseStaticExclusivity.cpp
+++ b/lib/SILOptimizer/Mandatory/DiagnoseStaticExclusivity.cpp
@@ -336,7 +336,7 @@ static StringRef extractExprText(const Expr *E, SourceManager &SM) {
 /// it is in the ifndef.
 #ifndef NDEBUG
 static bool isCallToStandardLibrarySwap(CallExpr *CE, ASTContext &Ctx) {
-  if (CE->getCalledValue() == Ctx.getSwap())
+  if (CE->getCalledValue(/*skipFunctionConversions=*/true) == Ctx.getSwap())
     return true;
 
   // Is the call module qualified, i.e. Swift.swap(&a[i], &[j)?
diff --git a/lib/SILOptimizer/Mandatory/DiagnoseUnreachable.cpp b/lib/SILOptimizer/Mandatory/DiagnoseUnreachable.cpp
index ea9051d3156ba..f2ddc950a02f9 100644
--- a/lib/SILOptimizer/Mandatory/DiagnoseUnreachable.cpp
+++ b/lib/SILOptimizer/Mandatory/DiagnoseUnreachable.cpp
@@ -926,9 +926,7 @@ static bool eliminateSwitchDispatchOnUnavailableElements(
   SmallVector<std::pair<EnumElementDecl *, SILBasicBlock *>, 4> NewCaseBBs;
   for (unsigned i : range(SWI.getNumCases())) {
     auto CaseBB = SWI.getCase(i);
-    auto availableAtr = CaseBB.first->getUnavailableAttr();
-
-    if (availableAtr && availableAtr->isUnconditionallyUnavailable()) {
+    if (!CaseBB.first->isAvailableDuringLowering()) {
       // Mark the basic block as potentially unreachable.
       SILBasicBlock *UnreachableBlock = CaseBB.second;
       if (!State->PossiblyUnreachableBlocks.contains(UnreachableBlock)) {
diff --git a/lib/SILOptimizer/Mandatory/Differentiation.cpp b/lib/SILOptimizer/Mandatory/Differentiation.cpp
index 1fc394e3920c9..62677b13cf7c4 100644
--- a/lib/SILOptimizer/Mandatory/Differentiation.cpp
+++ b/lib/SILOptimizer/Mandatory/Differentiation.cpp
@@ -999,10 +999,14 @@ bool DifferentiationTransformer::canonicalizeDifferentiabilityWitness(
 
   // We can generate empty JVP / VJP for functions available externally. These
   // functions have the same linkage as the original ones sans `external`
-  // flag. Important exception here hidden_external functions as they are
-  // serializable but corresponding hidden ones would be not and the SIL
-  // verifier will fail. Patch `serializeFunctions` for this case.
-  if (orig->getLinkage() == SILLinkage::HiddenExternal)
+  // flag. Important exception here hidden_external non-@_alwaysEmitIntoClient
+  // functions as they are serializable but corresponding hidden ones would be
+  // not and the SIL verifier will fail. Patch `serializeFunctions` for this
+  // case. For @_alwaysEmitIntoClient original functions (which might be
+  // HiddenExternal if we only have declaration without definition), we want
+  // derivatives to be serialized and do not patch `serializeFunctions`.
+  if (orig->getLinkage() == SILLinkage::HiddenExternal &&
+      !orig->markedAsAlwaysEmitIntoClient())
     serializeFunctions = IsNotSerialized;
 
   // If the JVP doesn't exist, need to synthesize it.
diff --git a/lib/SILOptimizer/Mandatory/FlowIsolation.cpp b/lib/SILOptimizer/Mandatory/FlowIsolation.cpp
index 26cd098062d61..41bd158bf2070 100644
--- a/lib/SILOptimizer/Mandatory/FlowIsolation.cpp
+++ b/lib/SILOptimizer/Mandatory/FlowIsolation.cpp
@@ -484,9 +484,9 @@ void Info::diagnoseAll(AnalysisInfo &info, bool forDeinit,
     VarDecl *var = cast<RefElementAddrInst>(use)->getField();
 
     diag.diagnose(illegalLoc.getSourceLoc(), diag::isolated_after_nonisolated,
-                  forDeinit, var->getDescriptiveKind(), var->getName())
-      .highlight(illegalLoc.getSourceRange())
-      .warnUntilSwiftVersion(6);
+                  forDeinit, var)
+        .highlight(illegalLoc.getSourceRange())
+        .warnUntilSwiftVersion(6);
 
     // after <verb><adjective> <subject>, ... can't use self anymore, etc ...
     //   example:
diff --git a/lib/SILOptimizer/Mandatory/IRGenPrepare.cpp b/lib/SILOptimizer/Mandatory/IRGenPrepare.cpp
index 5c5e9626f0cf2..0eeb42ee18963 100644
--- a/lib/SILOptimizer/Mandatory/IRGenPrepare.cpp
+++ b/lib/SILOptimizer/Mandatory/IRGenPrepare.cpp
@@ -124,11 +124,13 @@ class IRGenPrepare : public SILFunctionTransform {
     SILFunction *F = getFunction();
 
     if (getOptions().EmbeddedSwift) {
-      // In embedded swift all the code is generated in the top-level module.
-      // Even de-serialized functions must be code-gen'd.
+      // In Embedded Swift, code for a module can be generated into the clients
+      // that import that module (based on the de-serialized representation).
+      // When the model has a non-unique definition, use shared linkage for
+      // such definitions so they will be de-duplicated by the linker.
       SILLinkage linkage = F->getLinkage();
-      if (isAvailableExternally(linkage)) {
-        F->setLinkage(SILLinkage::Hidden);
+      if (isAvailableExternally(linkage) && F->hasNonUniqueDefinition()) {
+        F->setLinkage(SILLinkage::Shared);
       }
     }
 
diff --git a/lib/SILOptimizer/Mandatory/LowerHopToActor.cpp b/lib/SILOptimizer/Mandatory/LowerHopToActor.cpp
index 90b2a78328d6f..53f6d01110e46 100644
--- a/lib/SILOptimizer/Mandatory/LowerHopToActor.cpp
+++ b/lib/SILOptimizer/Mandatory/LowerHopToActor.cpp
@@ -51,7 +51,6 @@ namespace {
 /// inserts the derivations, turning those hops into hops to executors.
 /// IRGen expects hops to be to executors before it runs.
 class LowerHopToActor {
-  SILFunction *F;
   DominanceInfo *Dominance;
 
   /// A map from an actor value to the dominating instruction that
@@ -72,11 +71,7 @@ class LowerHopToActor {
                            SILValue actor, bool makeOptional);
 
 public:
-  LowerHopToActor(SILFunction *f,
-                  DominanceInfo *dominance)
-    : F(f),
-      Dominance(dominance)
-      { }
+  LowerHopToActor(DominanceInfo *dominance) : Dominance(dominance) {}
 
   /// The entry point to the transformation.
   bool run();
@@ -194,6 +189,118 @@ static AccessorDecl *getUnownedExecutorGetter(ASTContext &ctx,
   return nullptr;
 }
 
+/// Emit the instructions to derive an executor value from an actor value.
+static SILValue getExecutorForActor(SILBuilder &B, SILLocation loc,
+                                    SILValue actor) {
+  auto *F = actor->getFunction();
+  auto &ctx = F->getASTContext();
+  auto executorType = SILType::getPrimitiveObjectType(ctx.TheExecutorType);
+
+  // If the actor type is a default actor, go ahead and devirtualize here.
+  auto module = F->getModule().getSwiftModule();
+  CanType actorType = actor->getType().getASTType();
+
+  // Determine if the actor is a "default actor" in which case we'll build a
+  // default actor executor ref inline, rather than calling out to the
+  // user-provided executor function.
+  if (isDefaultActorType(actorType, module, F->getResilienceExpansion())) {
+    auto builtinName = ctx.getIdentifier(
+        getBuiltinName(BuiltinValueKind::BuildDefaultActorExecutorRef));
+    auto builtinDecl = cast<FuncDecl>(getBuiltinValueDecl(ctx, builtinName));
+    auto subs = SubstitutionMap::get(builtinDecl->getGenericSignature(),
+                                     {actorType}, LookUpConformanceInModule());
+    return B.createBuiltin(loc, builtinName, executorType, subs, {actor});
+  }
+
+  // Otherwise, go through (Distributed)Actor.unownedExecutor.
+  auto actorKind = actorType->isDistributedActor()
+                       ? KnownProtocolKind::DistributedActor
+                       : KnownProtocolKind::Actor;
+  auto actorProtocol = ctx.getProtocol(actorKind);
+  auto req = getUnownedExecutorGetter(ctx, actorProtocol);
+  assert(req && "Concurrency library broken");
+  SILDeclRef fn(req, SILDeclRef::Kind::Func);
+
+  // Open an existential actor type.
+  if (actorType->isExistentialType()) {
+    actorType = ExistentialArchetypeType::get(actorType)->getCanonicalType();
+    SILType loweredActorType = F->getLoweredType(actorType);
+    actor = B.createOpenExistentialRef(loc, actor, loweredActorType);
+  }
+
+  auto actorConf = lookupConformance(actorType, actorProtocol);
+  assert(actorConf && "hop_to_executor with actor that doesn't conform to "
+                      "Actor or DistributedActor");
+
+  auto subs = SubstitutionMap::get(req->getGenericSignature(), {actorType},
+                                   {actorConf});
+  auto fnType = F->getModule().Types.getConstantFunctionType(*F, fn);
+
+  auto witness = B.createWitnessMethod(loc, actorType, actorConf, fn,
+                                       SILType::getPrimitiveObjectType(fnType));
+  auto witnessCall = B.createApply(loc, witness, subs, {actor});
+
+  // The protocol requirement returns an UnownedSerialExecutor; extract
+  // the Builtin.Executor from it.
+  auto executorDecl = ctx.getUnownedSerialExecutorDecl();
+  auto executorProps = executorDecl->getStoredProperties();
+  assert(executorProps.size() == 1);
+  return B.createStructExtract(loc, witnessCall, executorProps[0]);
+}
+
+static SILValue getExecutorForOptionalActor(SILBuilder &B, SILLocation loc,
+                                            SILValue actor) {
+  auto &ctx = B.getASTContext();
+  auto executorType = SILType::getPrimitiveObjectType(ctx.TheExecutorType);
+  auto optionalExecutorType = SILType::getOptionalType(executorType);
+
+  // Unwrap the optional and call 'unownedExecutor'.
+  auto *someDecl = ctx.getOptionalSomeDecl();
+  auto *curBB = B.getInsertionBB();
+  auto *contBB = B.getInsertionPoint() == curBB->end()
+                     ? B.getFunction().createBasicBlockAfter(curBB)
+                     : curBB->split(B.getInsertionPoint());
+  auto *someBB = B.getFunction().createBasicBlockAfter(curBB);
+  auto *noneBB = B.getFunction().createBasicBlockAfter(someBB);
+
+  // unmarked executor
+  SILValue result = contBB->createPhiArgument(optionalExecutorType,
+                                              actor->getOwnershipKind());
+
+  SmallVector<std::pair<EnumElementDecl *, SILBasicBlock *>, 1> caseBBs;
+  caseBBs.push_back(std::make_pair(someDecl, someBB));
+  B.setInsertionPoint(curBB);
+  auto *switchEnum = B.createSwitchEnum(loc, actor, noneBB, caseBBs);
+
+  SILValue unwrappedActor;
+  if (B.hasOwnership()) {
+    unwrappedActor = switchEnum->createOptionalSomeResult();
+    B.setInsertionPoint(someBB);
+  } else {
+    B.setInsertionPoint(someBB);
+    unwrappedActor = B.createUncheckedEnumData(loc, actor, someDecl);
+  }
+
+  // Call 'unownedExecutor' in the some block and wrap the result into
+  // an optional.
+  SILValue unwrappedExecutor = getExecutorForActor(B, loc, unwrappedActor);
+  SILValue someValue =
+      B.createOptionalSome(loc, unwrappedExecutor, optionalExecutorType);
+  B.createBranch(loc, contBB, {someValue});
+
+  // In the none case, create a nil executor value, which represents
+  // the generic executor.
+  B.setInsertionPoint(noneBB);
+  SILValue noneValue = B.createOptionalNone(loc, optionalExecutorType);
+  B.createBranch(loc, contBB, {noneValue});
+  if (contBB->begin() == contBB->end()) {
+    B.setInsertionPoint(contBB);
+  } else {
+    B.setInsertionPoint(contBB->begin());
+  }
+  return result;
+}
+
 SILValue LowerHopToActor::emitGetExecutor(SILBuilderWithScope &B,
                                           SILLocation loc, SILValue actor,
                                           bool makeOptional) {
@@ -204,125 +311,31 @@ SILValue LowerHopToActor::emitGetExecutor(SILBuilderWithScope &B,
   // If the operand is already a BuiltinExecutorType, just wrap it
   // in an optional.
   if (makeOptional && actor->getType().is<BuiltinExecutorType>()) {
-    return B.createOptionalSome(
-        loc, actor,
-        SILType::getOptionalType(actor->getType()));
+    return B.createOptionalSome(loc, actor,
+                                SILType::getOptionalType(actor->getType()));
   }
 
-  auto &ctx = F->getASTContext();
-  auto executorType = SILType::getPrimitiveObjectType(ctx.TheExecutorType);
-  auto optionalExecutorType = SILType::getOptionalType(executorType);
-
-  /// Emit the instructions to derive an executor value from an actor value.
-  auto getExecutorFor = [&](SILValue actor) -> SILValue {
-    // If the actor type is a default actor, go ahead and devirtualize here.
-    auto module = F->getModule().getSwiftModule();
-    CanType actorType = actor->getType().getASTType();
-
-    // Determine if the actor is a "default actor" in which case we'll build a default
-    // actor executor ref inline, rather than calling out to the user-provided executor function.
-    if (isDefaultActorType(actorType, module, F->getResilienceExpansion())) {
-      auto builtinName = ctx.getIdentifier(
-        getBuiltinName(BuiltinValueKind::BuildDefaultActorExecutorRef));
-      auto builtinDecl = cast<FuncDecl>(getBuiltinValueDecl(ctx, builtinName));
-      auto subs = SubstitutionMap::get(builtinDecl->getGenericSignature(),
-                                       {actorType},
-                                       LookUpConformanceInModule());
-      return B.createBuiltin(loc, builtinName, executorType, subs, {actor});
-    }
-
-    // Otherwise, go through (Distributed)Actor.unownedExecutor.
-    auto actorKind = actorType->isDistributedActor() ?
-                     KnownProtocolKind::DistributedActor :
-                     KnownProtocolKind::Actor;
-    auto actorProtocol = ctx.getProtocol(actorKind);
-    auto req = getUnownedExecutorGetter(ctx, actorProtocol);
-    assert(req && "Concurrency library broken");
-    SILDeclRef fn(req, SILDeclRef::Kind::Func);
-
-    // Open an existential actor type.
-    if (actorType->isExistentialType()) {
-      actorType = ExistentialArchetypeType::get(actorType)->getCanonicalType();
-      SILType loweredActorType = F->getLoweredType(actorType);
-      actor = B.createOpenExistentialRef(loc, actor, loweredActorType);
-    }
-
-    auto actorConf = lookupConformance(actorType, actorProtocol);
-    assert(actorConf &&
-           "hop_to_executor with actor that doesn't conform to Actor or DistributedActor");
-
-    auto subs = SubstitutionMap::get(req->getGenericSignature(),
-                                     {actorType}, {actorConf});
-    auto fnType = F->getModule().Types.getConstantFunctionType(*F, fn);
-
-    auto witness =
-      B.createWitnessMethod(loc, actorType, actorConf, fn,
-                            SILType::getPrimitiveObjectType(fnType));
-    auto witnessCall = B.createApply(loc, witness, subs, {actor});
-
-    // The protocol requirement returns an UnownedSerialExecutor; extract
-    // the Builtin.Executor from it.
-    auto executorDecl = ctx.getUnownedSerialExecutorDecl();
-    auto executorProps = executorDecl->getStoredProperties();
-    assert(executorProps.size() == 1);
-    return B.createStructExtract(loc, witnessCall, executorProps[0]);
-  };
-
   bool needEndBorrow = false;
   SILValue unmarkedExecutor;
   if (auto wrappedActor = actorType->getOptionalObjectType()) {
     assert(makeOptional);
-
-    if (B.hasOwnership() && actor->getOwnershipKind() == OwnershipKind::Owned) {
+    if (B.hasOwnership() &&
+        actor->getOwnershipKind() != OwnershipKind::Guaranteed) {
       actor = B.createBeginBorrow(loc, actor);
       needEndBorrow = true;
     }
 
-    // Unwrap the optional and call 'unownedExecutor'.
-    auto *someDecl = B.getASTContext().getOptionalSomeDecl();
-    auto *curBB = B.getInsertionPoint()->getParent();
-    auto *contBB = curBB->split(B.getInsertionPoint());
-    auto *someBB = B.getFunction().createBasicBlockAfter(curBB);
-    auto *noneBB = B.getFunction().createBasicBlockAfter(someBB);
-
-    unmarkedExecutor = contBB->createPhiArgument(
-        optionalExecutorType, actor->getOwnershipKind());
-
-    SmallVector<std::pair<EnumElementDecl *, SILBasicBlock *>, 1> caseBBs;
-    caseBBs.push_back(std::make_pair(someDecl, someBB));
-    B.setInsertionPoint(curBB);
-    auto *switchEnum = B.createSwitchEnum(loc, actor, noneBB, caseBBs);
-
-    SILValue unwrappedActor;
-    if (B.hasOwnership()) {
-      unwrappedActor = switchEnum->createOptionalSomeResult();
-      B.setInsertionPoint(someBB);
-    } else {
-      B.setInsertionPoint(someBB);
-      unwrappedActor = B.createUncheckedEnumData(loc, actor, someDecl);
-    }
-
-    // Call 'unownedExecutor' in the some block and wrap the result into
-    // an optional.
-    SILValue unwrappedExecutor = getExecutorFor(unwrappedActor);
-    SILValue someValue =
-        B.createOptionalSome(loc, unwrappedExecutor, optionalExecutorType);
-    B.createBranch(loc, contBB, {someValue});
-
-    // In the none case, create a nil executor value, which represents
-    // the generic executor.
-    B.setInsertionPoint(noneBB);
-    SILValue noneValue = B.createOptionalNone(loc, optionalExecutorType);
-    B.createBranch(loc, contBB, {noneValue});
-    B.setInsertionPoint(contBB->begin());
+    unmarkedExecutor = getExecutorForOptionalActor(B, loc, actor);
   } else {
-    unmarkedExecutor = getExecutorFor(actor);
+    unmarkedExecutor = getExecutorForActor(B, loc, actor);
+  }
 
-    // Inject the result into an optional if requested.
-    if (makeOptional) {
-      unmarkedExecutor = B.createOptionalSome(loc, unmarkedExecutor,
-          SILType::getOptionalType(unmarkedExecutor->getType()));
-    }
+  // Inject the result into an optional if requested and if our executor is not
+  // yet optional.
+  if (makeOptional && !unmarkedExecutor->getType().getOptionalObjectType()) {
+    unmarkedExecutor = B.createOptionalSome(
+        loc, unmarkedExecutor,
+        SILType::getOptionalType(unmarkedExecutor->getType()));
   }
 
   // Mark the dependence of the resulting value on the actor value to
@@ -342,7 +355,7 @@ class LowerHopToActorPass : public SILFunctionTransform {
   void run() override {
     auto fn = getFunction();
     auto domTree = getAnalysis<DominanceAnalysis>()->get(fn);
-    LowerHopToActor pass(getFunction(), domTree);
+    LowerHopToActor pass(domTree);
     if (pass.run())
       invalidateAnalysis(SILAnalysis::InvalidationKind::BranchesAndInstructions);
   }
diff --git a/lib/SILOptimizer/Mandatory/MandatoryInlining.cpp b/lib/SILOptimizer/Mandatory/MandatoryInlining.cpp
index 783b9597c107f..7d161aebb752f 100644
--- a/lib/SILOptimizer/Mandatory/MandatoryInlining.cpp
+++ b/lib/SILOptimizer/Mandatory/MandatoryInlining.cpp
@@ -70,6 +70,11 @@ static void diagnose(ASTContext &Context, SourceLoc loc, Diag<T...> diag,
   Context.Diags.diagnose(loc, diag, std::forward<U>(args)...);
 }
 
+enum class MandatoryInlining_t {
+  transparent,
+  inlineAlways
+};
+
 /// Fixup reference counts after inlining a function call (which is a no-op
 /// unless the function is a thick function).
 ///
@@ -368,7 +373,7 @@ static SILValue cleanupLoadedCalleeValue(SILValue calleeValue) {
                                                           calleeValue);
         sri->eraseFromParent();
       } else {
-        auto *dvi = destroy.get<DestroyValueInst *>();
+        auto *dvi = cast<DestroyValueInst *>(destroy);
         SILBuilderWithScope(dvi).emitDestroyValueAndFold(dvi->getLoc(),
                                                          calleeValue);
         dvi->eraseFromParent();
@@ -673,7 +678,8 @@ static SILFunction *
 getCalleeFunction(SILFunction *F, FullApplySite AI, bool &IsThick,
                   SmallVectorImpl<ParameterConvention> &CapturedArgConventions,
                   SmallVectorImpl<SILValue> &FullArgs,
-                  PartialApplyInst *&PartialApply) {
+                  PartialApplyInst *&PartialApply,
+                  MandatoryInlining_t whatToInline) {
   IsThick = false;
   PartialApply = nullptr;
   CapturedArgConventions.clear();
@@ -744,8 +750,20 @@ getCalleeFunction(SILFunction *F, FullApplySite AI, bool &IsThick,
 
   // If the CalleeFunction is a not-transparent definition, we can not process
   // it.
-  if (CalleeFunction->isTransparent() == IsNotTransparent)
+  if (whatToInline == MandatoryInlining_t::transparent &&
+      CalleeFunction->isTransparent() == IsNotTransparent)
+    return nullptr;
+
+  // If the CalleeFunction is not inline(always) definition, we can not process
+  // it.
+  bool calleeThunkIsTransparentAndAThunk =
+    CalleeFunction->isTransparent() == IsTransparent &&
+    CalleeFunction->isThunk();
+  if (whatToInline == MandatoryInlining_t::inlineAlways &&
+      CalleeFunction->getInlineStrategy() != AlwaysInline &&
+      !calleeThunkIsTransparentAndAThunk) {
     return nullptr;
+  }
 
   // If CalleeFunction is a declaration, see if we can load it.
   if (CalleeFunction->empty())
@@ -807,7 +825,8 @@ runOnFunctionRecursively(SILOptFunctionBuilder &FuncBuilder, SILPassManager *pm,
                          ImmutableFunctionSet::Factory &SetFactory,
                          ImmutableFunctionSet CurrentInliningSet,
                          ClassHierarchyAnalysis *CHA,
-                         DenseFunctionSet &changedFunctions) {
+                         DenseFunctionSet &changedFunctions,
+                         MandatoryInlining_t whatToInline) {
   // Avoid reprocessing functions needlessly.
   if (FullyInlinedSet.count(F))
     return true;
@@ -818,8 +837,10 @@ runOnFunctionRecursively(SILOptFunctionBuilder &FuncBuilder, SILPassManager *pm,
     assert(AI && "Cannot have circular inline without apply");
     SILLocation L = AI.getLoc();
     assert(L && "Must have location for transparent inline apply");
+
     diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(),
-             diag::circular_transparent);
+             whatToInline == MandatoryInlining_t::transparent ?
+               diag::circular_transparent : diag::circular_inlineAlways);
     return false;
   }
 
@@ -870,7 +891,8 @@ runOnFunctionRecursively(SILOptFunctionBuilder &FuncBuilder, SILPassManager *pm,
       bool IsThick;
       PartialApplyInst *PAI;
       SILFunction *CalleeFunction = getCalleeFunction(
-          F, InnerAI, IsThick, CapturedArgConventions, FullArgs, PAI);
+          F, InnerAI, IsThick, CapturedArgConventions, FullArgs, PAI,
+          whatToInline);
 
       if (!CalleeFunction)
         continue;
@@ -878,7 +900,7 @@ runOnFunctionRecursively(SILOptFunctionBuilder &FuncBuilder, SILPassManager *pm,
       // Then recursively process it first before trying to inline it.
       if (!runOnFunctionRecursively(
               FuncBuilder, pm, CalleeFunction, InnerAI, FullyInlinedSet, SetFactory,
-              CurrentInliningSet, CHA, changedFunctions)) {
+              CurrentInliningSet, CHA, changedFunctions, whatToInline)) {
         // If we failed due to circular inlining, then emit some notes to
         // trace back the failure if we have more information.
         // FIXME: possibly it could be worth recovering and attempting other
@@ -909,7 +931,10 @@ runOnFunctionRecursively(SILOptFunctionBuilder &FuncBuilder, SILPassManager *pm,
         }));
 
       SILInliner Inliner(FuncBuilder, deleter,
-                         SILInliner::InlineKind::MandatoryInline, Subs);
+                         whatToInline == MandatoryInlining_t::transparent ?
+                           SILInliner::InlineKind::MandatoryInline :
+                           SILInliner::InlineKind::InlineAlwaysInline,
+                         Subs);
       if (!Inliner.canInlineApplySite(InnerAI))
         continue;
 
@@ -1019,6 +1044,9 @@ runOnFunctionRecursively(SILOptFunctionBuilder &FuncBuilder, SILPassManager *pm,
 namespace {
 
 class MandatoryInlining : public SILModuleTransform {
+
+  MandatoryInlining_t whatToInline;
+
   /// The entry point to the transformation.
   void run() override {
     ClassHierarchyAnalysis *CHA = getAnalysis<ClassHierarchyAnalysis>();
@@ -1052,7 +1080,8 @@ class MandatoryInlining : public SILModuleTransform {
 
       runOnFunctionRecursively(FuncBuilder, getPassManager(), &F, FullApplySite(),
                                FullyInlinedSet, SetFactory,
-                               SetFactory.getEmptySet(), CHA, changedFunctions);
+                               SetFactory.getEmptySet(), CHA, changedFunctions,
+                               whatToInline);
 
       // The inliner splits blocks at call sites. Re-merge trivial branches
       // to reestablish a canonical CFG.
@@ -1075,9 +1104,15 @@ class MandatoryInlining : public SILModuleTransform {
     }
   }
 
+public:
+  MandatoryInlining(MandatoryInlining_t whatToInline) :
+    whatToInline(whatToInline) {}
 };
 } // end anonymous namespace
 
 SILTransform *swift::createMandatoryInlining() {
-  return new MandatoryInlining();
+  return new MandatoryInlining(MandatoryInlining_t::transparent);
+}
+SILTransform *swift::createInlineAlwaysInlining() {
+  return new MandatoryInlining(MandatoryInlining_t::inlineAlways);
 }
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyAddressChecker.h b/lib/SILOptimizer/Mandatory/MoveOnlyAddressChecker.h
deleted file mode 100644
index e69de29bb2d1d..0000000000000
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyAddressCheckerTester.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyAddressCheckerTester.cpp
index 16a7518406928..4614dd7104f5d 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyAddressCheckerTester.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyAddressCheckerTester.cpp
@@ -45,8 +45,8 @@
 #include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
 #include "swift/SILOptimizer/Analysis/NonLocalAccessBlockAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/PointerIntPair.h"
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyAddressCheckerUtils.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyAddressCheckerUtils.cpp
index d84ddace1edcb..34f5730d0b933 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyAddressCheckerUtils.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyAddressCheckerUtils.cpp
@@ -243,7 +243,7 @@
 #include "swift/SIL/FieldSensitivePrunedLiveness.h"
 #include "swift/SIL/InstructionUtils.h"
 #include "swift/SIL/MemAccessUtils.h"
-#include "swift/SIL/OSSALifetimeCompletion.h"
+#include "swift/SIL/OSSACompleteLifetime.h"
 #include "swift/SIL/OwnershipUtils.h"
 #include "swift/SIL/PrunedLiveness.h"
 #include "swift/SIL/SILArgument.h"
@@ -259,8 +259,8 @@
 #include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
 #include "swift/SILOptimizer/Analysis/NonLocalAccessBlockAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/PointerIntPair.h"
@@ -1113,6 +1113,14 @@ addressBeginsInitialized(MarkUnresolvedNonCopyableValueInst *address) {
     return true;
   }
 
+  if (auto *applyInst = dyn_cast_or_null<ApplyInst>(
+          stripAccessMarkers(operand)->getDefiningInstruction())) {
+    if (applyInst->hasGuaranteedAddressResult()) {
+      LLVM_DEBUG(llvm::dbgs() << "Adding apply as init!\n");
+      return true;
+    }
+  }
+
   if (isa<UncheckedTakeEnumDataAddrInst>(stripAccessMarkers(operand))) {
     LLVM_DEBUG(llvm::dbgs()
                << "Adding enum projection as init!\n");
@@ -1472,7 +1480,7 @@ struct MoveOnlyAddressCheckerPImpl {
   /// The instruction deleter used by \p canonicalizer.
   InstructionDeleter deleter;
 
-  /// State to run CanonicalizeOSSALifetime.
+  /// State to run OSSACanonicalizeOwned.
   OSSACanonicalizer canonicalizer;
 
   /// Per mark must check address use state.
@@ -1856,8 +1864,7 @@ shouldEmitPartialMutationError(UseState &useState, PartialMutation::Kind kind,
   if (feature &&
       !fn->getModule().getASTContext().LangOpts.hasFeature(*feature) &&
       !isa<DropDeinitInst>(user)) {
-    LLVM_DEBUG(llvm::dbgs()
-               << "    " << getFeatureName(*feature) << " disabled!\n");
+    LLVM_DEBUG(llvm::dbgs() << "    " << feature->getName() << " disabled!\n");
     // If the types equal, just bail early.
     // Emit the error.
     return {PartialMutationError::featureDisabled(iterType, kind)};
@@ -1896,7 +1903,7 @@ shouldEmitPartialMutationError(UseState &useState, PartialMutation::Kind kind,
     // Otherwise, walk one level towards our child type. We unconditionally
     // unwrap since we should never fail here due to earlier checking.
     std::tie(iterPair, iterType) =
-        *pair.walkOneLevelTowardsChild(iterPair, iterType, fn);
+        *pair.walkOneLevelTowardsChild(iterPair, iterType, targetType, fn);
   }
 
   return {};
@@ -2184,7 +2191,12 @@ bool GatherUsesVisitor::visitUse(Operand *op) {
   // Ignore end_access.
   if (isa<EndAccessInst>(user))
     return true;
-    
+  
+  // Ignore end_cow_mutation_addr.
+  if (isa<EndCOWMutationAddrInst>(user)) {
+    return true;
+  }
+
   // Ignore sanitizer markers.
   if (auto bu = dyn_cast<BuiltinInst>(user)) {
     if (bu->getBuiltinKind() == BuiltinValueKind::TSanInoutAccess) {
@@ -2409,6 +2421,12 @@ bool GatherUsesVisitor::visitUse(Operand *op) {
           return true;
         }
 
+        if (operand->isBorrowAccessorResult()) {
+          moveChecker.diagnosticEmitter.emitObjectGuaranteedDiagnostic(
+              markedValue);
+          return true;
+        }
+
         // Finally try to emit either a global or class field error...
         if (!moveChecker.diagnosticEmitter
                  .emitGlobalOrClassFieldLoadedAndConsumed(markedValue)) {
@@ -3428,6 +3446,10 @@ void MoveOnlyAddressCheckerPImpl::rewriteUses(
       auto accessPath = AccessPathWithBase::computeInScope(copy->getSrc());
       if (auto *access = dyn_cast_or_null<BeginAccessInst>(accessPath.base))
         access->setAccessKind(SILAccessKind::Modify);
+      if (auto *oeai =
+              dyn_cast_or_null<OpenExistentialAddrInst>(copy->getSrc())) {
+        oeai->setAccessKind(OpenedExistentialAccess::Mutable);
+      }
       copy->setIsTakeOfSrc(IsTake);
       continue;
     }
@@ -4063,13 +4085,12 @@ bool MoveOnlyAddressChecker::check(
   return pimpl.changed;
 }
 bool MoveOnlyAddressChecker::completeLifetimes() {
-  // TODO: Delete once OSSALifetimeCompletion is run as part of SILGenCleanup
+  // TODO: Delete once OSSACompleteLifetime is run as part of SILGenCleanup
   bool changed = false;
 
   // Lifetimes must be completed inside out (bottom-up in the CFG).
   PostOrderFunctionInfo *postOrder = poa->get(fn);
-  OSSALifetimeCompletion completion(fn, domTree,
-                                    *deadEndBlocksAnalysis->get(fn));
+  OSSACompleteLifetime completion(fn, domTree, *deadEndBlocksAnalysis->get(fn));
   for (auto *block : postOrder->getPostOrder()) {
     for (SILInstruction &inst : reverse(*block)) {
       for (auto result : inst.getResults()) {
@@ -4078,7 +4099,7 @@ bool MoveOnlyAddressChecker::completeLifetimes() {
           continue;
         }
         if (completion.completeOSSALifetime(
-                result, OSSALifetimeCompletion::Boundary::Availability) ==
+                result, OSSACompleteLifetime::Boundary::Availability) ==
             LifetimeCompletion::WasCompleted) {
           changed = true;
         }
@@ -4089,7 +4110,7 @@ bool MoveOnlyAddressChecker::completeLifetimes() {
         continue;
       }
       if (completion.completeOSSALifetime(
-              arg, OSSALifetimeCompletion::Boundary::Availability) ==
+              arg, OSSACompleteLifetime::Boundary::Availability) ==
           LifetimeCompletion::WasCompleted) {
         changed = true;
       }
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyBorrowToDestructureUtils.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyBorrowToDestructureUtils.cpp
index a2300bcb41265..cb247d16eecdd 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyBorrowToDestructureUtils.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyBorrowToDestructureUtils.cpp
@@ -302,6 +302,17 @@ bool Implementation::gatherUses(SILValue value) {
       // copyable values as normal uses.
       if (auto *cvi = dyn_cast<CopyValueInst>(nextUse->getUser())) {
         if (cvi->getOperand()->getType().isMoveOnly()) {
+          // Borrow accessor's callsite consists of copy_value +
+          // mark_unresolved_non_copyable_value instructions.
+          // It's diagnostics are driven by the
+          // mark_unresolved_non_copyable_value instruction.
+          // Ignore the copy_value uses to avoid an incoherent error.
+          if (cvi->getOperand()->isBorrowAccessorResult()) {
+            assert(isa<MarkUnresolvedNonCopyableValueInst>(
+                cvi->getSingleConsumingUse()->getUser()));
+            continue;
+          }
+
           LLVM_DEBUG(llvm::dbgs() << "        Found copy value of move only "
                                      "field... looking through!\n");
           for (auto *use : cvi->getUses())
@@ -877,7 +888,6 @@ AvailableValues &Implementation::computeAvailableValues(SILBasicBlock *block) {
       llvm::dbgs()
       << "    Destructuring available values in preds to smallest size for bb"
       << block->getDebugID() << '\n');
-  auto *fn = block->getFunction();
   IntervalMapAllocator::Map typeSpanToValue(getAllocator());
   for (auto *predBlock : predsSkippingBackEdges) {
     SWIFT_DEFER { typeSpanToValue.clear(); };
@@ -930,20 +940,10 @@ AvailableValues &Implementation::computeAvailableValues(SILBasicBlock *block) {
       // smallest offset size could result in further destructuring that an
       // earlier value required. Instead, we do a final loop afterwards using
       // the interval map to update each available value.
-      auto iterType = iterValue->getType();
       auto loc = getSafeLoc(predBlock->getTerminator());
       SILBuilderWithScope builder(predBlock->getTerminator());
 
       while (smallestOffsetSize->first.size < iterOffsetSize.size) {
-        TypeOffsetSizePair childOffsetSize;
-        SILType childType;
-
-        // We are returned an optional here and should never fail... so use a
-        // force unwrap.
-        std::tie(childOffsetSize, childType) =
-            *iterOffsetSize.walkOneLevelTowardsChild(iterOffsetSize, iterType,
-                                                     fn);
-
         // Before we destructure ourselves, erase our entire value from the
         // map. We do not need to consider the possibility of there being holes
         // in our range since we always store values whole to their entire
@@ -1401,8 +1401,8 @@ void Implementation::rewriteUses(InstructionDeleter *deleter) {
 
           // Then walk one level towards our target type.
           std::tie(iterOffsetSize, iterType) =
-              *useOffsetSize.walkOneLevelTowardsChild(parentOffsetSize,
-                                                      iterType, fn);
+              *useOffsetSize.walkOneLevelTowardsChild(
+                  parentOffsetSize, iterType, unwrappedOperandType, fn);
 
           unsigned start = parentOffsetSize.startOffset;
           consumeBuilder.emitDestructureValueOperation(
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyBorrowToDestructureUtils.h b/lib/SILOptimizer/Mandatory/MoveOnlyBorrowToDestructureUtils.h
index a4b4b695a1b1b..f4ce2b3a66645 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyBorrowToDestructureUtils.h
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyBorrowToDestructureUtils.h
@@ -1,4 +1,4 @@
-//===--- MoveOnlyBorrowToDestructure.h ------------------------------------===//
+//===--- MoveOnlyBorrowToDestructureUtils.h -------------------------------===//
 //
 // This source file is part of the Swift.org open source project
 //
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyChecker.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyChecker.cpp
index a27ffc9d5398a..b1e0e4e191a11 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyChecker.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyChecker.cpp
@@ -31,7 +31,7 @@
 #include "swift/SIL/FieldSensitivePrunedLiveness.h"
 #include "swift/SIL/InstructionUtils.h"
 #include "swift/SIL/MemAccessUtils.h"
-#include "swift/SIL/OSSALifetimeCompletion.h"
+#include "swift/SIL/OSSACompleteLifetime.h"
 #include "swift/SIL/OwnershipUtils.h"
 #include "swift/SIL/PrunedLiveness.h"
 #include "swift/SIL/SILArgument.h"
@@ -47,8 +47,8 @@
 #include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
 #include "swift/SILOptimizer/Analysis/NonLocalAccessBlockAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/PointerIntPair.h"
@@ -122,14 +122,14 @@ void MoveOnlyChecker::checkObjects() {
 
 void MoveOnlyChecker::completeObjectLifetimes(
     ArrayRef<MarkUnresolvedNonCopyableValueInst *> insts) {
-// TODO: Delete once OSSALifetimeCompletion is run as part of SILGenCleanup.
-OSSALifetimeCompletion completion(fn, domTree, *deba->get(fn));
-
-// Collect all values derived from each mark_unresolved_non_copyable_value
-// instruction via ownership instructions and phis.
-ValueWorklist transitiveValues(fn);
-for (auto *inst : insts) {
-  transitiveValues.push(inst);
+  // TODO: Delete once OSSACompleteLifetime is run as part of SILGenCleanup.
+  OSSACompleteLifetime completion(fn, domTree, *deba->get(fn));
+
+  // Collect all values derived from each mark_unresolved_non_copyable_value
+  // instruction via ownership instructions and phis.
+  ValueWorklist transitiveValues(fn);
+  for (auto *inst : insts) {
+    transitiveValues.push(inst);
   }
   while (auto value = transitiveValues.pop()) {
     for (auto *use : value->getUses()) {
@@ -163,21 +163,27 @@ for (auto *inst : insts) {
   for (auto *block : poa->get(fn)->getPostOrder()) {
     for (SILInstruction &inst : reverse(*block)) {
       for (auto result : inst.getResults()) {
+        if (llvm::any_of(result->getUsers(),
+                         [](auto *user) { return isa<BranchInst>(user); })) {
+          continue;
+        }
         if (!transitiveValues.isVisited(result))
           continue;
         if (completion.completeOSSALifetime(
-                result, OSSALifetimeCompletion::Boundary::Availability) ==
+                result, OSSACompleteLifetime::Boundary::Availability) ==
             LifetimeCompletion::WasCompleted) {
           madeChange = true;
         }
       }
     }
     for (SILArgument *arg : block->getArguments()) {
-      assert(!arg->isReborrow() && "reborrows not legal at this SIL stage");
+      if (arg->isReborrow()) {
+        continue;
+      }
       if (!transitiveValues.isVisited(arg))
         continue;
       if (completion.completeOSSALifetime(
-              arg, OSSALifetimeCompletion::Boundary::Availability) ==
+              arg, OSSACompleteLifetime::Boundary::Availability) ==
           LifetimeCompletion::WasCompleted) {
         madeChange = true;
       }
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyDiagnostics.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyDiagnostics.cpp
index fb0357d55ec3c..514391ada4e0c 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyDiagnostics.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyDiagnostics.cpp
@@ -828,10 +828,6 @@ void DiagnosticEmitter::emitCannotPartiallyMutateError(
     return;
   }
   case PartialMutationError::Kind::HasDeinit: {
-    assert(
-        astContext.LangOpts.hasFeature(Feature::MoveOnlyPartialConsumption) ||
-        astContext.LangOpts.hasFeature(
-            Feature::MoveOnlyPartialReinitialization));
     auto diagnostic = [&]() {
       switch (kind) {
       case PartialMutation::Kind::Consume:
@@ -851,10 +847,6 @@ void DiagnosticEmitter::emitCannotPartiallyMutateError(
     return;
   }
   case PartialMutationError::Kind::NonfrozenImportedType: {
-    assert(
-        astContext.LangOpts.hasFeature(Feature::MoveOnlyPartialConsumption) ||
-        astContext.LangOpts.hasFeature(
-            Feature::MoveOnlyPartialReinitialization));
     auto &nominal = error.getNonfrozenImportedNominal();
     auto diagnostic = [&]() {
       switch (kind) {
@@ -870,10 +862,6 @@ void DiagnosticEmitter::emitCannotPartiallyMutateError(
     return;
   }
   case PartialMutationError::Kind::NonfrozenUsableFromInlineType: {
-    assert(
-        astContext.LangOpts.hasFeature(Feature::MoveOnlyPartialConsumption) ||
-        astContext.LangOpts.hasFeature(
-            Feature::MoveOnlyPartialReinitialization));
     auto &nominal = error.getNonfrozenUsableFromInlineNominal();
     auto diagnostic = [&]() {
       switch (kind) {
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerTester.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerTester.cpp
index 975bae0dd3748..3203d7a00de75 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerTester.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerTester.cpp
@@ -42,8 +42,8 @@
 #include "swift/SILOptimizer/Analysis/PostOrderAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/CFGOptUtils.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "swift/SILOptimizer/Utils/SILSSAUpdater.h"
 #include "clang/AST/DeclTemplate.h"
 #include "llvm/ADT/ArrayRef.h"
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerUtils.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerUtils.cpp
index 130ea65dc9eb2..cc4dfb3f9af3b 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerUtils.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerUtils.cpp
@@ -41,8 +41,8 @@
 #include "swift/SILOptimizer/Analysis/PostOrderAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/CFGOptUtils.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "swift/SILOptimizer/Utils/SILSSAUpdater.h"
 #include "clang/AST/DeclTemplate.h"
 #include "llvm/ADT/ArrayRef.h"
@@ -102,7 +102,7 @@ void OSSACanonicalizer::computeBoundaryData(SILValue value) {
   // Then use that information to stash for our diagnostics the boundary
   // consuming/non-consuming users as well as enter the boundary consuming users
   // into the boundaryConsumignUserSet for quick set testing later.
-  using IsInterestingUser = CanonicalizeOSSALifetime::IsInterestingUser;
+  using IsInterestingUser = OSSACanonicalizeOwned::IsInterestingUser;
   InstructionSet boundaryConsumingUserSet(value->getFunction());
   for (auto *lastUser : originalBoundary.lastUsers) {
     LLVM_DEBUG(llvm::dbgs() << "Looking at boundary use: " << *lastUser);
@@ -185,6 +185,9 @@ struct MoveOnlyObjectCheckerPImpl {
 
   bool
   checkForSameInstMultipleUseErrors(MarkUnresolvedNonCopyableValueInst *base);
+
+  bool eraseMarkWithCopiedOperand(
+    MarkUnresolvedNonCopyableValueInst *markedInst);
 };
 
 } // namespace
@@ -463,9 +466,6 @@ void MoveOnlyObjectCheckerPImpl::check(
   // MarkUnresolvedNonCopyableValueInst in Raw SIL. This ensures we do not
   // miss any.
   //
-  // NOTE: destroys is a separate array that we use to avoid iterator
-  // invalidation when cleaning up destroy_value of guaranteed checked values.
-  SmallVector<DestroyValueInst *, 8> destroys;
   while (!moveIntroducersToProcess.empty()) {
     auto *markedInst = moveIntroducersToProcess.pop_back_val();
 
@@ -475,80 +475,113 @@ void MoveOnlyObjectCheckerPImpl::check(
     if (!diagnosticEmitter.emittedDiagnosticForValue(markedInst)) {
       if (markedInst->getCheckKind() ==
           MarkUnresolvedNonCopyableValueInst::CheckKind::NoConsumeOrAssign) {
-        if (auto *cvi = dyn_cast<CopyValueInst>(markedInst->getOperand())) {
-          auto replacement = cvi->getOperand();
-          auto orig = replacement;
-          if (auto *copyToMoveOnly =
-                  dyn_cast<CopyableToMoveOnlyWrapperValueInst>(orig)) {
-            orig = copyToMoveOnly->getOperand();
-          }
-
-          // TODO: Instead of pattern matching specific code generation patterns,
-          // we should be able to eliminate any `copy_value` whose canonical
-          // lifetime fits within the borrow scope of the borrowed value being
-          // copied from.
-
-          // Handle:
-          //
-          // bb(%arg : @guaranteed $Type):
-          //   %copy = copy_value %arg
-          //   %mark = mark_unresolved_non_copyable_value [no_consume_or_assign] %copy
-          if (auto *arg = dyn_cast<SILArgument>(orig)) {
-            if (arg->getOwnershipKind() == OwnershipKind::Guaranteed) {
-              for (auto *use : markedInst->getConsumingUses()) {
-                destroys.push_back(cast<DestroyValueInst>(use->getUser()));
-              }
-              while (!destroys.empty())
-                destroys.pop_back_val()->eraseFromParent();
-              markedInst->replaceAllUsesWith(replacement);
-              markedInst->eraseFromParent();
-              cvi->eraseFromParent();
-              continue;
-            }
-          }
-
-          // Handle:
-          //
-          //   %1 = load_borrow %0
-          //   %2 = copy_value %1
-          //   %3 = mark_unresolved_non_copyable_value [no_consume_or_assign] %2
-          if (isa<LoadBorrowInst>(orig)) {
-            for (auto *use : markedInst->getConsumingUses()) {
-              destroys.push_back(cast<DestroyValueInst>(use->getUser()));
-            }
-            while (!destroys.empty())
-              destroys.pop_back_val()->eraseFromParent();
-            markedInst->replaceAllUsesWith(replacement);
-            markedInst->eraseFromParent();
-            cvi->eraseFromParent();
-            continue;
-          }
-          
-          // Handle:
-          //   (%yield, ..., %handle) = begin_apply
-          //   %copy = copy_value %yield
-          //   %mark = mark_unresolved_noncopyable_value [no_consume_or_assign] %copy
-          if (isa_and_nonnull<BeginApplyInst>(orig->getDefiningInstruction())) {
-            if (orig->getOwnershipKind() == OwnershipKind::Guaranteed) {
-              for (auto *use : markedInst->getConsumingUses()) {
-                destroys.push_back(cast<DestroyValueInst>(use->getUser()));
-              }
-              while (!destroys.empty())
-                destroys.pop_back_val()->eraseFromParent();
-              markedInst->replaceAllUsesWith(replacement);
-              markedInst->eraseFromParent();
-              cvi->eraseFromParent();
-              continue;
-            }
-          }
+        if (eraseMarkWithCopiedOperand(markedInst)) {
+          changed = true;
+          continue;
         }
       }
+      markedInst->replaceAllUsesWith(markedInst->getOperand());
+      markedInst->eraseFromParent();
+      changed = true;
     }
+  }
+}
+
+/// Erase a copy_value operand of MarkUnresolvedNonCopyableValueInst.
+bool MoveOnlyObjectCheckerPImpl::eraseMarkWithCopiedOperand(
+  MarkUnresolvedNonCopyableValueInst *markedInst)
+{
+  auto *cvi = dyn_cast<CopyValueInst>(markedInst->getOperand());
+  if (!cvi)
+    return false;
+
+  auto replacement = cvi->getOperand();
+  auto orig = replacement;
+  while (true) {
+    if (auto *copyToMoveOnly =
+        dyn_cast<CopyableToMoveOnlyWrapperValueInst>(orig)) {
+      orig = copyToMoveOnly->getOperand();
+      continue;
+    }
+    if (auto *markDep = dyn_cast<MarkDependenceInst>(orig)) {
+      orig = markDep->getValue();
+      continue;
+    }
+    break;
+  }
+
+  // TODO: Instead of pattern matching specific code generation patterns,
+  // we should be able to eliminate any `copy_value` whose canonical
+  // lifetime fits within the borrow scope of the borrowed value being
+  // copied from.
 
-    markedInst->replaceAllUsesWith(markedInst->getOperand());
+  // NOTE: destroys is a separate array that we use to avoid iterator
+  // invalidation when cleaning up destroy_value of guaranteed checked values.
+  SmallVector<DestroyValueInst *, 8> destroys;
+
+  // Handle:
+  //
+  // bb(%arg : @guaranteed $Type):
+  //   %copy = copy_value %arg
+  //   %mark = mark_unresolved_non_copyable_value [no_consume_or_assign]
+  //   %copy
+  if (auto *arg = dyn_cast<SILArgument>(orig)) {
+    if (arg->getOwnershipKind() == OwnershipKind::Guaranteed) {
+      for (auto *use : markedInst->getConsumingUses()) {
+        destroys.push_back(cast<DestroyValueInst>(use->getUser()));
+      }
+      while (!destroys.empty())
+        destroys.pop_back_val()->eraseFromParent();
+      markedInst->replaceAllUsesWith(replacement);
+      markedInst->eraseFromParent();
+      cvi->eraseFromParent();
+      return true;
+    }
+  }
+
+  // Handle:
+  //
+  //   %1 = load_borrow %0
+  //   %2 = copy_value %1
+  //   %3 = mark_unresolved_non_copyable_value [no_consume_or_assign] %2
+  if (isa<LoadBorrowInst>(orig)) {
+    for (auto *use : markedInst->getConsumingUses()) {
+      destroys.push_back(cast<DestroyValueInst>(use->getUser()));
+    }
+    while (!destroys.empty())
+      destroys.pop_back_val()->eraseFromParent();
+    markedInst->replaceAllUsesWith(replacement);
     markedInst->eraseFromParent();
-    changed = true;
+    cvi->eraseFromParent();
+    return true;
+  }
+
+  // Handle:
+  //   (%yield, ..., %handle) = begin_apply
+  //   %copy = copy_value %yield
+  //   %mark = mark_unresolved_noncopyable_value [no_consume_or_assign]
+  //   %copy
+  //   Borrow accessors:
+  //   %borrowed_return = apply
+  //   %copy = copy_value %borrowed_return
+  //   %mark = mark_unresolved_noncopyable_value [no_consume_or_assign]
+  //   %copy
+  if (isa_and_nonnull<BeginApplyInst>(orig->getDefiningInstruction()) ||
+      isa_and_nonnull<ApplyInst>(orig->getDefiningInstruction())) {
+    if (orig->getOwnershipKind() == OwnershipKind::Guaranteed) {
+      for (auto *use : markedInst->getConsumingUses()) {
+        destroys.push_back(cast<DestroyValueInst>(use->getUser()));
+      }
+      while (!destroys.empty())
+        destroys.pop_back_val()->eraseFromParent();
+      markedInst->replaceAllUsesWith(replacement);
+      markedInst->eraseFromParent();
+      cvi->eraseFromParent();
+      return true;
+    }
   }
+
+  return false;
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerUtils.h b/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerUtils.h
index cefd8551db131..b3050ab0ef228 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerUtils.h
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerUtils.h
@@ -20,7 +20,7 @@
 #ifndef SWIFT_SILOPTIMIZER_MANDATORY_MOVEONLYOBJECTCHECKERUTILS_H
 #define SWIFT_SILOPTIMIZER_MANDATORY_MOVEONLYOBJECTCHECKERUTILS_H
 
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "llvm/Support/Compiler.h"
 
 #include "MoveOnlyBorrowToDestructureUtils.h"
@@ -30,7 +30,7 @@ namespace siloptimizer {
 
 class DiagnosticEmitter;
 
-/// Wrapper around CanonicalizeOSSALifetime that we use to specialize its
+/// Wrapper around OSSACanonicalizeOwned that we use to specialize its
 /// interface for our purposes.
 struct OSSACanonicalizer {
   /// A per mark must check, vector of uses that copy propagation says need a
@@ -44,7 +44,7 @@ struct OSSACanonicalizer {
   /// A list of non-consuming boundary uses.
   SmallVector<SILInstruction *, 32> nonConsumingBoundaryUsers;
 
-  CanonicalizeOSSALifetime canonicalizer;
+  OSSACanonicalizeOwned canonicalizer;
 
   OSSACanonicalizer(SILFunction *fn, DominanceInfo *domTree,
                     DeadEndBlocksAnalysis *deadEndBlocksAnalysis,
@@ -62,7 +62,7 @@ struct OSSACanonicalizer {
 
   struct LivenessState {
     OSSACanonicalizer &parent;
-    CanonicalizeOSSALifetime::LivenessState canonicalizerState;
+    OSSACanonicalizeOwned::LivenessState canonicalizerState;
 
     LivenessState(OSSACanonicalizer &parent, SILValue def)
         : parent(parent), canonicalizerState(parent.canonicalizer, def, {}) {}
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyTypeUtils.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyTypeUtils.cpp
index 3bfc839a50162..52be83e98f27a 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyTypeUtils.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyTypeUtils.cpp
@@ -26,7 +26,7 @@ static StructDecl *getFullyReferenceableStruct(SILType ktypeTy) {
 std::optional<std::pair<TypeOffsetSizePair, SILType>>
 TypeOffsetSizePair::walkOneLevelTowardsChild(
     TypeOffsetSizePair ancestorOffsetSize, SILType ancestorType,
-    SILFunction *fn) const {
+    SILType childType, SILFunction *fn) const {
   assert(ancestorOffsetSize.size >= size &&
          "Too large to be a child of ancestorType");
   assert((ancestorOffsetSize.startOffset <= startOffset &&
@@ -127,6 +127,16 @@ TypeOffsetSizePair::walkOneLevelTowardsChild(
     llvm_unreachable("Not a child of this enum?!");
   }
 
+  if (ancestorType.isExistentialType()) {
+    assert(childType);
+    auto childArchetypeType =
+        childType.getASTType()->getAs<ExistentialArchetypeType>();
+    assert(childArchetypeType);
+    assert(childArchetypeType->getExistentialType()->getCanonicalType() ==
+           ancestorType.getASTType());
+    return {{ancestorOffsetSize, childType}};
+  }
+
   llvm_unreachable("Hit a leaf type?! Should have handled it earlier");
 }
 
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyTypeUtils.h b/lib/SILOptimizer/Mandatory/MoveOnlyTypeUtils.h
index a9fbfc1f48bf0..e2e2416fe6a5c 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyTypeUtils.h
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyTypeUtils.h
@@ -64,7 +64,8 @@ struct TypeOffsetSizePair {
   /// be a child type of \p ancestorType.
   std::optional<std::pair<TypeOffsetSizePair, SILType>>
   walkOneLevelTowardsChild(TypeOffsetSizePair ancestorOffsetSize,
-                           SILType ancestorType, SILFunction *fn) const;
+                           SILType ancestorType, SILType childType,
+                           SILFunction *fn) const;
 
   /// Given an ancestor offset \p ancestorOffset and a type called \p
   /// ancestorType, walk one level towards this current type inserting on value,
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyUtils.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyUtils.cpp
index c9cb406609181..0780988490354 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyUtils.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyUtils.cpp
@@ -45,8 +45,8 @@
 #include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
 #include "swift/SILOptimizer/Analysis/NonLocalAccessBlockAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/PointerIntPair.h"
@@ -218,7 +218,8 @@ bool noncopyable::memInstMustInitialize(Operand *memOper) {
   }
   case SILInstructionKind::BuiltinInst: {
     auto bi = cast<BuiltinInst>(memInst);
-    if (bi->getBuiltinKind() == BuiltinValueKind::ZeroInitializer) {
+    if (bi->getBuiltinKind() == BuiltinValueKind::ZeroInitializer ||
+        bi->getBuiltinKind() == BuiltinValueKind::PrepareInitialization) {
       // `zeroInitializer` with an address operand zeroes out the address operand
       return true;
     }
@@ -252,6 +253,9 @@ bool noncopyable::memInstMustReinitialize(Operand *memOper) {
     auto *CAI = cast<ExplicitCopyAddrInst>(memInst);
     return CAI->getDest() == address && !CAI->isInitializationOfDest();
   }
+  case SILInstructionKind::MarkDependenceAddrInst: {
+    return true;
+  }
   case SILInstructionKind::YieldInst: {
     auto *yield = cast<YieldInst>(memInst);
     return yield->getYieldInfoForOperand(*memOper).isIndirectInOut();
@@ -297,6 +301,7 @@ bool noncopyable::memInstMustConsume(Operand *memOper) {
            (CAI->getDest() == address && !CAI->isInitializationOfDest());
   }
   case SILInstructionKind::DestroyAddrInst:
+  case SILInstructionKind::EndLifetimeInst:
     return true;
   case SILInstructionKind::DropDeinitInst:
     assert(memOper->get()->getType().isValueTypeWithDeinit());
diff --git a/lib/SILOptimizer/Mandatory/MoveOnlyWrappedTypeEliminator.cpp b/lib/SILOptimizer/Mandatory/MoveOnlyWrappedTypeEliminator.cpp
index c386e131c03a7..3f5264980f0ac 100644
--- a/lib/SILOptimizer/Mandatory/MoveOnlyWrappedTypeEliminator.cpp
+++ b/lib/SILOptimizer/Mandatory/MoveOnlyWrappedTypeEliminator.cpp
@@ -48,7 +48,7 @@
 #include "swift/SILOptimizer/Analysis/NonLocalAccessBlockAnalysis.h"
 #include "swift/SILOptimizer/Analysis/PostOrderAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 
 using namespace swift;
 
@@ -60,6 +60,28 @@ namespace {
 
 struct SILMoveOnlyWrappedTypeEliminatorVisitor
     : SILInstructionVisitor<SILMoveOnlyWrappedTypeEliminatorVisitor, bool> {
+
+  // Instructions waiting to be visited.
+  llvm::SmallSetVector<SILInstruction *, 8> &pendingInsts;
+  llvm::SmallVector<SILInstruction *, 8> deferredInsts;
+
+  SILMoveOnlyWrappedTypeEliminatorVisitor(llvm::SmallSetVector<SILInstruction *, 8> &pendingInsts):
+    pendingInsts(pendingInsts)
+  {}
+
+  // If 'user's operand is not yet visited, push it onto the end of
+  // 'pendingInsts' and pretend we didn't see it yet. This is only relevant for
+  // non-address operands in which ownership should be consistent.
+  bool waitFor(SILInstruction *user, SILValue operand) {
+    if (auto *def = operand.getDefiningInstruction()) {
+      if (pendingInsts.contains(def)) {
+        deferredInsts.push_back(user);
+        return false;
+      }
+    }
+    return true;
+  }
+
   bool visitSILInstruction(SILInstruction *inst) {
     llvm::errs() << "Unhandled SIL Instruction: " << *inst;
     llvm_unreachable("error");
@@ -79,6 +101,9 @@ struct SILMoveOnlyWrappedTypeEliminatorVisitor
   }
 
   bool visitStoreInst(StoreInst *si) {
+    if (!waitFor(si, si->getSrc())) {
+      return false;
+    }
     if (!si->getSrc()->getType().isTrivial(*si->getFunction()))
       return false;
     si->setOwnershipQualifier(StoreOwnershipQualifier::Trivial);
@@ -86,6 +111,9 @@ struct SILMoveOnlyWrappedTypeEliminatorVisitor
   }
 
   bool visitStoreBorrowInst(StoreBorrowInst *si) {
+    if (!waitFor(si, si->getSrc())) {
+      return false;
+    }
     if (!si->getSrc()->getType().isTrivial(*si->getFunction()))
       return false;
     SILBuilderWithScope b(si);
@@ -177,41 +205,44 @@ struct SILMoveOnlyWrappedTypeEliminatorVisitor
 
 #define NO_UPDATE_NEEDED(CLS)                                                  \
   bool visit##CLS##Inst(CLS##Inst *inst) { return false; }
-  NO_UPDATE_NEEDED(AllocStack)
+  NO_UPDATE_NEEDED(AddressToPointer)
   NO_UPDATE_NEEDED(AllocBox)
-  NO_UPDATE_NEEDED(ProjectBox)
+  NO_UPDATE_NEEDED(AllocStack)
+  NO_UPDATE_NEEDED(AutoreleaseValue)
+  NO_UPDATE_NEEDED(BeginAccess)
+  NO_UPDATE_NEEDED(Branch)
+  NO_UPDATE_NEEDED(BridgeObjectToRef)
+  NO_UPDATE_NEEDED(Builtin)
+  NO_UPDATE_NEEDED(CheckedCastBranch)
+  NO_UPDATE_NEEDED(ClassMethod)
+  NO_UPDATE_NEEDED(ConvertFunction)
+  NO_UPDATE_NEEDED(CopyAddr)
+  NO_UPDATE_NEEDED(DeallocBox)
+  NO_UPDATE_NEEDED(DeallocStack)
   NO_UPDATE_NEEDED(DebugValue)
-  NO_UPDATE_NEEDED(StructElementAddr)
-  NO_UPDATE_NEEDED(TupleElementAddr)
-  NO_UPDATE_NEEDED(UncheckedTakeEnumDataAddr)
-  NO_UPDATE_NEEDED(DestructureTuple)
+  NO_UPDATE_NEEDED(DestroyAddr)
   NO_UPDATE_NEEDED(DestructureStruct)
-  NO_UPDATE_NEEDED(SelectEnum)
+  NO_UPDATE_NEEDED(DestructureTuple)
+  NO_UPDATE_NEEDED(EndAccess)
+  NO_UPDATE_NEEDED(EndCOWMutationAddr)
+  NO_UPDATE_NEEDED(ExistentialMetatype)
+  NO_UPDATE_NEEDED(ExplicitCopyAddr)
+  NO_UPDATE_NEEDED(FixLifetime)
+  NO_UPDATE_NEEDED(IgnoredUse)
   NO_UPDATE_NEEDED(MarkDependence)
   NO_UPDATE_NEEDED(MarkDependenceAddr)
-  NO_UPDATE_NEEDED(DestroyAddr)
-  NO_UPDATE_NEEDED(DeallocStack)
-  NO_UPDATE_NEEDED(DeallocBox)
-  NO_UPDATE_NEEDED(Branch)
-  NO_UPDATE_NEEDED(ExplicitCopyAddr)
-  NO_UPDATE_NEEDED(CopyAddr)
-  NO_UPDATE_NEEDED(RefElementAddr)
-  NO_UPDATE_NEEDED(CheckedCastBranch)
+  NO_UPDATE_NEEDED(ObjCMethod)
   NO_UPDATE_NEEDED(Object)
-  NO_UPDATE_NEEDED(OpenExistentialRef)
   NO_UPDATE_NEEDED(OpenExistentialAddr)
   NO_UPDATE_NEEDED(OpenExistentialBox)
-  NO_UPDATE_NEEDED(ConvertFunction)
+  NO_UPDATE_NEEDED(OpenExistentialRef)
+  NO_UPDATE_NEEDED(ProjectBox)
+  NO_UPDATE_NEEDED(RefElementAddr)
   NO_UPDATE_NEEDED(RefToBridgeObject)
-  NO_UPDATE_NEEDED(BridgeObjectToRef)
-  NO_UPDATE_NEEDED(BeginAccess)
-  NO_UPDATE_NEEDED(EndAccess)
-  NO_UPDATE_NEEDED(ClassMethod)
-  NO_UPDATE_NEEDED(FixLifetime)
-  NO_UPDATE_NEEDED(AddressToPointer)
-  NO_UPDATE_NEEDED(ExistentialMetatype)
-  NO_UPDATE_NEEDED(Builtin)
-  NO_UPDATE_NEEDED(IgnoredUse)
+  NO_UPDATE_NEEDED(SelectEnum)
+  NO_UPDATE_NEEDED(StructElementAddr)
+  NO_UPDATE_NEEDED(TupleElementAddr)
+  NO_UPDATE_NEEDED(UncheckedTakeEnumDataAddr)
 #undef NO_UPDATE_NEEDED
 
   bool eliminateIdentityCast(SingleValueInstruction *svi) {
@@ -228,6 +259,7 @@ struct SILMoveOnlyWrappedTypeEliminatorVisitor
   }
   ELIMINATE_POTENTIAL_IDENTITY_CAST(Upcast)
   ELIMINATE_POTENTIAL_IDENTITY_CAST(UncheckedAddrCast)
+  ELIMINATE_POTENTIAL_IDENTITY_CAST(UncheckedRefCast)
   ELIMINATE_POTENTIAL_IDENTITY_CAST(UnconditionalCheckedCast)
 #undef ELIMINATE_POTENTIAL_IDENTITY_CAST
   // We handle apply sites by just inserting a convert_function that converts
@@ -332,6 +364,9 @@ bool SILMoveOnlyWrappedTypeEliminator::process() {
     return true;
   };
 
+  // (1) Check each value's type for the MoveOnly wrapper, (2) strip the wrapper
+  // type, and (3) add all uses to 'touchedInsts' in forward order for
+  // efficiency.
   for (auto &bb : *fn) {
     for (auto *arg : bb.getArguments()) {
       bool relevant = visitValue(arg);
@@ -377,9 +412,18 @@ bool SILMoveOnlyWrappedTypeEliminator::process() {
     madeChange = true;
   }
 
-  SILMoveOnlyWrappedTypeEliminatorVisitor visitor;
-  while (!touchedInsts.empty()) {
-    visitor.visit(touchedInsts.pop_back_val());
+  SILMoveOnlyWrappedTypeEliminatorVisitor visitor{touchedInsts};
+  while(true) {
+    while (!touchedInsts.empty()) {
+      visitor.visit(touchedInsts.pop_back_val());
+    }
+    if (visitor.deferredInsts.empty())
+      break;
+
+    for (auto *inst : visitor.deferredInsts) {
+      touchedInsts.insert(inst);
+    }
+    visitor.deferredInsts.clear();
   }
 
   return madeChange;
diff --git a/lib/SILOptimizer/Mandatory/OSLogOptimization.cpp b/lib/SILOptimizer/Mandatory/OSLogOptimization.cpp
index 69cd337c2a6cc..2d20916364896 100644
--- a/lib/SILOptimizer/Mandatory/OSLogOptimization.cpp
+++ b/lib/SILOptimizer/Mandatory/OSLogOptimization.cpp
@@ -163,9 +163,9 @@ class StringSILInfo {
 
     this->stringInitIntrinsic = callee;
 
-    MetatypeInst *stringMetatypeInst =
-        dyn_cast<MetatypeInst>(inst->getOperand(4)->getDefiningInstruction());
-    this->stringMetatype = stringMetatypeInst->getType();
+    auto stringMetatype = inst->getOperand(4)->getType();
+    assert(stringMetatype.isMetatype());
+    this->stringMetatype = stringMetatype;
   }
 
   bool isInitialized() { return stringInitIntrinsic != nullptr; }
diff --git a/lib/SILOptimizer/Mandatory/OptimizeHopToExecutor.cpp b/lib/SILOptimizer/Mandatory/OptimizeHopToExecutor.cpp
index fc4a42e89e671..d9680f40b2efe 100644
--- a/lib/SILOptimizer/Mandatory/OptimizeHopToExecutor.cpp
+++ b/lib/SILOptimizer/Mandatory/OptimizeHopToExecutor.cpp
@@ -119,6 +119,12 @@ class OptimizeHopToExecutor {
 /// Search for hop_to_executor instructions and add their operands to \p actors.
 void OptimizeHopToExecutor::collectActors(Actors &actors) {
   int uniqueActorID = 0;
+
+  if (auto isolation = function->getActorIsolation();
+      isolation && isolation->isCallerIsolationInheriting()) {
+    actors[function->maybeGetIsolatedArgument()] = uniqueActorID++;
+  }
+
   for (SILBasicBlock &block : *function) {
     for (SILInstruction &inst : block) {
       if (auto *hop = dyn_cast<HopToExecutorInst>(&inst)) {
@@ -193,12 +199,13 @@ void OptimizeHopToExecutor::solveDataflowBackward() {
 /// Returns true if \p inst is a suspension point or an async call.
 static bool isSuspensionPoint(SILInstruction *inst) {
   if (auto applySite = FullApplySite::isa(inst)) {
-    if (applySite.isAsync())
+    if (applySite.isAsync() && !applySite.isCallerIsolationInheriting())
       return true;
     return false;
   }
   if (isa<AwaitAsyncContinuationInst>(inst))
     return true;
+
   return false;
 }
 
@@ -209,8 +216,20 @@ bool OptimizeHopToExecutor::removeRedundantHopToExecutors(const Actors &actors)
 
   // Initialize the dataflow.
   for (BlockState &state : blockStates) {
-    state.entry = (state.block == function->getEntryBlock() ?
-                     BlockState::Unknown : BlockState::NotSet);
+    state.entry = [&]() -> int {
+      if (state.block != function->getEntryBlock()) {
+        return BlockState::NotSet;
+      }
+
+      if (auto isolation = function->getActorIsolation();
+          isolation && isolation->isCallerIsolationInheriting()) {
+        auto *fArg =
+            cast<SILFunctionArgument>(function->maybeGetIsolatedArgument());
+        return actors.lookup(SILValue(fArg));
+      }
+
+      return BlockState::Unknown;
+    }();
     state.intra = BlockState::NotSet;
     for (SILInstruction &inst : *state.block) {
       if (isSuspensionPoint(&inst)) {
@@ -311,10 +330,12 @@ void OptimizeHopToExecutor::updateNeedExecutor(int &needExecutor,
     needExecutor = BlockState::NoExecutorNeeded;
     return;
   }
+
   if (isSuspensionPoint(inst)) {
     needExecutor = BlockState::NoExecutorNeeded;
     return;
   }
+
   if (needsExecutor(inst))
     needExecutor = BlockState::ExecutorNeeded;
 }
@@ -364,6 +385,29 @@ bool OptimizeHopToExecutor::needsExecutor(SILInstruction *inst) {
   if (isa<BeginBorrowInst>(inst) || isa<EndBorrowInst>(inst)) {
     return false;
   }
+
+  // A call to a caller isolation inheriting function does not create dead
+  // executors since caller isolation inheriting functions do not hop in their
+  // prologue.
+  if (auto fas = FullApplySite::isa(inst);
+      fas && fas.isAsync() && fas.isCallerIsolationInheriting()) {
+    return true;
+  }
+
+  // Treat returns from a caller isolation inheriting function as requiring the
+  // liveness of hop to executors before it.
+  //
+  // DISCUSSION: We do this since callers of callee functions with isolation
+  // inheriting isolation are not required to have a hop after the return from
+  // the callee function... so we have no guarantee that there isn't code in the
+  // caller that needs this hop to executor to run on the correct actor.
+  if (isa<ReturnInst>(inst)) {
+    if (auto isolation = inst->getFunction()->getActorIsolation();
+        isolation && isolation->isCallerIsolationInheriting()) {
+      return true;
+    }
+  }
+
   return inst->mayReadOrWriteMemory();
 }
 
diff --git a/lib/SILOptimizer/Mandatory/OwnershipModelEliminator.cpp b/lib/SILOptimizer/Mandatory/OwnershipModelEliminator.cpp
index 191d52677aeec..1339507d3fe6c 100644
--- a/lib/SILOptimizer/Mandatory/OwnershipModelEliminator.cpp
+++ b/lib/SILOptimizer/Mandatory/OwnershipModelEliminator.cpp
@@ -22,6 +22,8 @@
 ///
 //===----------------------------------------------------------------------===//
 
+#include "swift/AST/Types.h"
+#include "swift/SIL/SILValue.h"
 #define DEBUG_TYPE "sil-ownership-model-eliminator"
 
 #include "swift/Basic/Assertions.h"
@@ -404,6 +406,20 @@ bool OwnershipModelEliminatorVisitor::visitApplyInst(ApplyInst *ai) {
     changed = true;
   }
 
+  // Insert a retain for unowned results.
+  SILBuilderWithScope builder(ai->getNextInstruction(), builderCtx);
+  auto resultIt = fnConv.getDirectSILResults().begin();
+  auto copyValue = [&](unsigned idx, SILValue v) {
+    auto result = *resultIt;
+    if (result.getConvention() == ResultConvention::Unowned)
+      builder.emitCopyValueOperation(ai->getLoc(), v);
+    ++resultIt;
+  };
+  if (fnConv.getNumDirectSILResults() == 1)
+    copyValue(0, ai);
+  else
+    builder.emitDestructureValueOperation(ai->getLoc(), ai, copyValue);
+
   return changed;
 }
 
@@ -871,17 +887,6 @@ static bool stripOwnership(SILFunction &func) {
   return madeChange;
 }
 
-static void prepareNonTransparentSILFunctionForOptimization(ModuleDecl *,
-                                                            SILFunction *f) {
-  if (!f->hasOwnership() || f->isTransparent())
-    return;
-
-  LLVM_DEBUG(llvm::dbgs() << "After deserialization, stripping ownership in:"
-                          << f->getName() << "\n");
-
-  stripOwnership(*f);
-}
-
 static void prepareSILFunctionForOptimization(ModuleDecl *, SILFunction *f) {
   if (!f->hasOwnership())
     return;
@@ -895,11 +900,7 @@ static void prepareSILFunctionForOptimization(ModuleDecl *, SILFunction *f) {
 namespace {
 
 struct OwnershipModelEliminator : SILFunctionTransform {
-  bool skipTransparent;
-  bool skipStdlibModule;
-
-  OwnershipModelEliminator(bool skipTransparent, bool skipStdlibModule)
-      : skipTransparent(skipTransparent), skipStdlibModule(skipStdlibModule) {}
+  OwnershipModelEliminator() {}
 
   void run() override {
     if (DumpBefore.size()) {
@@ -909,20 +910,9 @@ struct OwnershipModelEliminator : SILFunctionTransform {
     auto *f = getFunction();
     auto &mod = getFunction()->getModule();
 
-    // If we are supposed to skip the stdlib module and we are in the stdlib
-    // module bail.
-    if (skipStdlibModule && mod.isStdlibModule()) {
-      return;
-    }
-
     if (!f->hasOwnership())
       return;
 
-    // If we were asked to not strip ownership from transparent functions in
-    // /our/ module, return.
-    if (skipTransparent && f->isTransparent())
-      return;
-
     // Verify here to make sure ownership is correct before we strip.
     {
       // Add a pretty stack trace entry to tell users who see a verification
@@ -950,25 +940,14 @@ struct OwnershipModelEliminator : SILFunctionTransform {
       invalidateAnalysis(InvalidKind);
     }
 
-    // If we were asked to strip transparent, we are at the beginning of the
-    // performance pipeline. In such a case, we register a handler so that all
-    // future things we deserialize have ownership stripped.
+    // Register a handler so that all future things we deserialize have ownership stripped.
     using NotificationHandlerTy =
         FunctionBodyDeserializationNotificationHandler;
     std::unique_ptr<DeserializationNotificationHandler> ptr;
-    if (skipTransparent) {
-      if (!mod.hasRegisteredDeserializationNotificationHandlerForNonTransparentFuncOME()) {
-        ptr.reset(new NotificationHandlerTy(
-            prepareNonTransparentSILFunctionForOptimization));
-        mod.registerDeserializationNotificationHandler(std::move(ptr));
-        mod.setRegisteredDeserializationNotificationHandlerForNonTransparentFuncOME();
-      }
-    } else {
-      if (!mod.hasRegisteredDeserializationNotificationHandlerForAllFuncOME()) {
-        ptr.reset(new NotificationHandlerTy(prepareSILFunctionForOptimization));
-        mod.registerDeserializationNotificationHandler(std::move(ptr));
-        mod.setRegisteredDeserializationNotificationHandlerForAllFuncOME();
-      }
+    if (!mod.hasRegisteredDeserializationNotificationHandlerForAllFuncOME()) {
+      ptr.reset(new NotificationHandlerTy(prepareSILFunctionForOptimization));
+      mod.registerDeserializationNotificationHandler(std::move(ptr));
+      mod.setRegisteredDeserializationNotificationHandlerForAllFuncOME();
     }
   }
 };
@@ -976,11 +955,5 @@ struct OwnershipModelEliminator : SILFunctionTransform {
 } // end anonymous namespace
 
 SILTransform *swift::createOwnershipModelEliminator() {
-  return new OwnershipModelEliminator(false /*skip transparent*/,
-                                      false /*ignore stdlib*/);
-}
-
-SILTransform *swift::createNonTransparentFunctionOwnershipModelEliminator() {
-  return new OwnershipModelEliminator(true /*skip transparent*/,
-                                      false /*ignore stdlib*/);
+  return new OwnershipModelEliminator();
 }
diff --git a/lib/SILOptimizer/Mandatory/PerformanceDiagnostics.cpp b/lib/SILOptimizer/Mandatory/PerformanceDiagnostics.cpp
index 52d714807fbf9..633fee2330050 100644
--- a/lib/SILOptimizer/Mandatory/PerformanceDiagnostics.cpp
+++ b/lib/SILOptimizer/Mandatory/PerformanceDiagnostics.cpp
@@ -20,6 +20,7 @@
 #include "swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/BasicBlockOptUtils.h"
+#include "swift/SILOptimizer/Utils/VariableNameUtils.h"
 #include "llvm/Support/Debug.h"
 
 using namespace swift;
@@ -94,10 +95,6 @@ class PerformanceDiagnostics {
     return visitFunction(function, perfConstr, /*parentLoc*/ nullptr);
   }
 
-  bool visitFunctionEmbeddedSwift(SILFunction *function) {
-    return visitFunctionEmbeddedSwift(function, /*parentLoc*/ nullptr);
-  }
-
   /// Check functions _without_ performance annotations.
   ///
   /// This is need to check closure arguments of called performance-annotated
@@ -108,9 +105,6 @@ class PerformanceDiagnostics {
   bool visitFunction(SILFunction *function, PerformanceConstraints perfConstr,
                         LocWithParent *parentLoc);
 
-  bool visitFunctionEmbeddedSwift(SILFunction *function,
-                                  LocWithParent *parentLoc);
-
   bool visitInst(SILInstruction *inst, PerformanceConstraints perfConstr,
                     LocWithParent *parentLoc);
 
@@ -157,123 +151,6 @@ static bool isEffectFreeArraySemanticCall(SILInstruction *inst) {
   }
 }
 
-static bool hasGenericValueDeinit(SILType ty, SILFunction *f) {
-  if (!ty.isMoveOnly())
-    return false;
-  NominalTypeDecl *nominal = ty.getNominalOrBoundGenericNominal();
-  if (!nominal)
-    return false;
-
-  if (nominal->getGenericSignature() && nominal->getValueTypeDestructor())
-    return true;
-
-  if (isa<StructDecl>(nominal)) {
-    for (unsigned i = 0, n = ty.getNumNominalFields(); i < n; ++i) {
-      if (hasGenericValueDeinit(ty.getFieldType(i, f), f))
-        return true;
-    }
-  } else if (auto *en = dyn_cast<EnumDecl>(nominal)) {
-    for (EnumElementDecl *element : en->getAllElements()) {
-      if (element->hasAssociatedValues()) {
-        if (hasGenericValueDeinit(ty.getEnumElementType(element, f), f))
-          return true;
-      }
-    }
-  }
-
-  return false;
-}
-
-static bool allocsGenericValueTypeWithDeinit(AllocBoxInst *abi) {
-  CanSILBoxType boxTy = abi->getBoxType();
-  SILFunction *f = abi->getFunction();
-  unsigned numFields = boxTy->getLayout()->getFields().size();
-  for (unsigned fieldIdx = 0; fieldIdx < numFields; ++fieldIdx) {
-    SILType fieldTy = getSILBoxFieldType(TypeExpansionContext(*f), boxTy,
-                                         abi->getModule().Types, fieldIdx);
-    if (hasGenericValueDeinit(fieldTy, f))
-      return true;
-  }
-  return false;
-}
-
-/// Prints Embedded Swift specific performance diagnostics (no existentials,
-/// no metatypes, optionally no allocations) for \p function.
-bool PerformanceDiagnostics::visitFunctionEmbeddedSwift(
-    SILFunction *function, LocWithParent *parentLoc) {
-  // Don't check generic functions in embedded Swift, they're about to be
-  // removed anyway.
-  if (function->isGeneric())
-    return false;
-
-  if (!function->isDefinition())
-    return false;
-
-  if (visitedFuncs.contains(function))
-    return false;
-  visitedFuncs[function] = PerformanceConstraints::None;
-
-  for (SILBasicBlock &block : *function) {
-    for (SILInstruction &inst : block) {
-      if (visitInst(&inst, PerformanceConstraints::None, parentLoc)) {
-        if (inst.getLoc().getSourceLoc().isInvalid()) {
-          auto demangledName = Demangle::demangleSymbolAsString(
-              inst.getFunction()->getName(),
-              Demangle::DemangleOptions::SimplifiedUIDemangleOptions());
-          llvm::errs() << "in function " << demangledName << "\n";
-        }
-        LLVM_DEBUG(llvm::dbgs() << inst << *inst.getFunction());
-        return true;
-      }
-
-      if (auto as = FullApplySite::isa(&inst)) {
-        LocWithParent asLoc(inst.getLoc().getSourceLoc(), parentLoc);
-        LocWithParent *loc = &asLoc;
-        if (parentLoc &&
-            asLoc.loc == inst.getFunction()->getLocation().getSourceLoc())
-          loc = parentLoc;
-
-        for (SILFunction *callee : bca->getCalleeList(as)) {
-          if (visitFunctionEmbeddedSwift(callee, loc))
-            return true;
-        }
-      } else if (auto *bi = dyn_cast<BuiltinInst>(&inst)) {
-        PrettyStackTracePerformanceDiagnostics stackTrace(
-            "visitFunction::BuiltinInst (once, once with context)", &inst);
-
-        switch (bi->getBuiltinInfo().ID) {
-        case BuiltinValueKind::Once:
-        case BuiltinValueKind::OnceWithContext:
-          if (auto *fri = dyn_cast<FunctionRefInst>(bi->getArguments()[1])) {
-            LocWithParent asLoc(bi->getLoc().getSourceLoc(), parentLoc);
-            LocWithParent *loc = &asLoc;
-            if (parentLoc &&
-                asLoc.loc == bi->getFunction()->getLocation().getSourceLoc())
-              loc = parentLoc;
-
-            if (visitFunctionEmbeddedSwift(fri->getReferencedFunction(), loc))
-              return true;
-          }
-          break;
-        default:
-          break;
-        }
-      } else if (auto *abi = dyn_cast<AllocBoxInst>(&inst)) {
-        // It needs a bit of work to support alloc_box of generic non-copyable
-        // structs/enums with deinit, because we need to specialize the deinit
-        // functions, though they are not explicitly referenced in SIL.
-        // Until this is supported, give an error in such cases. Otherwise
-        // IRGen would crash.
-        if (allocsGenericValueTypeWithDeinit(abi)) {
-          LocWithParent loc(abi->getLoc().getSourceLoc(), parentLoc);
-          diagnose(loc, diag::embedded_capture_of_generic_value_with_deinit);
-        }
-      }
-    }
-  }
-  return false;
-}
-
 /// Prints performance diagnostics for \p function.
 bool PerformanceDiagnostics::visitFunction(SILFunction *function,
                                               PerformanceConstraints perfConstr,
@@ -331,7 +208,7 @@ bool PerformanceDiagnostics::visitFunction(SILFunction *function,
             if (auto *fri = dyn_cast<FunctionRefInst>(bi->getArguments()[1])) {
               if (visitCallee(bi, fri->getReferencedFunction(), perfConstr, parentLoc))
                 return true;
-            } else {
+            } else if (perfConstr != PerformanceConstraints::ManualOwnership) {
               LocWithParent loc(inst.getLoc().getSourceLoc(), parentLoc);
               diagnose(loc, diag::performance_unknown_callees);
               return true;
@@ -373,6 +250,12 @@ bool PerformanceDiagnostics::checkClosureValue(SILValue closure,
                                             SILInstruction *callInst,
                                             PerformanceConstraints perfConstr,
                                             LocWithParent *parentLoc) {
+  // Closures within a function are pre-annotated with [manual_ownership]
+  // within SILGen, if they're visible to users for annotation at all.
+  // So no recursive closure checking is needed here.
+  if (perfConstr == PerformanceConstraints::ManualOwnership)
+    return false;
+
   // Walk through the definition of the closure until we find the "underlying"
   // function_ref instruction.
   while (!isa<FunctionRefInst>(closure)) {
@@ -417,6 +300,11 @@ bool PerformanceDiagnostics::visitCallee(SILInstruction *callInst,
                                          CalleeList callees,
                                          PerformanceConstraints perfConstr,
                                          LocWithParent *parentLoc) {
+  // Manual Ownership is not checked recursively within callees of the function,
+  // it's a local, non-viral performance annotation.
+  if (perfConstr == PerformanceConstraints::ManualOwnership)
+    return false;
+
   LocWithParent asLoc(callInst->getLoc().getSourceLoc(), parentLoc);
   LocWithParent *loc = &asLoc;
   if (parentLoc && asLoc.loc == callInst->getFunction()->getLocation().getSourceLoc())
@@ -477,8 +365,7 @@ static bool metatypeUsesAreNotRelevant(MetatypeInst *mt) {
       if (auto *callee = apply->getReferencedFunctionOrNull()) {
         // Exclude `Swift._diagnoseUnexpectedEnumCaseValue<A, B>(type: A.Type, rawValue: B) -> Swift.Never`
         // It's a fatal error function, used for imported C enums.
-        if (callee->getName() == "$ss32_diagnoseUnexpectedEnumCaseValue4type03rawE0s5NeverOxm_q_tr0_lF" &&
-            !mt->getModule().getOptions().EmbeddedSwift) {
+        if (callee->getName() == "$ss32_diagnoseUnexpectedEnumCaseValue4type03rawE0s5NeverOxm_q_tr0_lF") {
           continue;
         }
       }
@@ -488,25 +375,6 @@ static bool metatypeUsesAreNotRelevant(MetatypeInst *mt) {
   return true;
 }
 
-static bool allowedMetadataUseInEmbeddedSwift(SILInstruction *inst) {
-  // Only diagnose metatype, value_metatype instructions, ...
-  if ((isa<ValueMetatypeInst>(inst) || isa<MetatypeInst>(inst))) {
-    auto metaTy = cast<SingleValueInstruction>(inst)->getType().castTo<MetatypeType>();
-    if (metaTy->getRepresentation() == MetatypeRepresentation::Thick) {
-      Type instTy = metaTy->getInstanceType();
-      if (auto selfType = instTy->getAs<DynamicSelfType>())
-        instTy = selfType->getSelfType();
-      // Class metadata are supported in embedded Swift
-      return instTy->getClassOrBoundGenericClass() ? true : false;
-    }
-  // ... and alloc_ref_dynamic, for now.
-  } else if (isa<AllocRefDynamicInst>(inst)) {
-    return false;
-  }
-
-  return true;
-}
-
 bool PerformanceDiagnostics::visitInst(SILInstruction *inst,
                                           PerformanceConstraints perfConstr,
                                           LocWithParent *parentLoc) {
@@ -514,6 +382,116 @@ bool PerformanceDiagnostics::visitInst(SILInstruction *inst,
   RuntimeEffect impact = getRuntimeEffect(inst, impactType);
   LocWithParent loc(inst->getLoc().getSourceLoc(), parentLoc);
 
+  if (perfConstr == PerformanceConstraints::ManualOwnership) {
+    if (impact & RuntimeEffect::RefCounting) {
+      bool shouldDiagnose = false;
+      switch (inst->getKind()) {
+      case SILInstructionKind::PartialApplyInst:
+      case SILInstructionKind::DestroyAddrInst:
+      case SILInstructionKind::DestroyValueInst:
+      case SILInstructionKind::StoreInst:
+        break; // These modify reference counts, but aren't copies.
+      case SILInstructionKind::ExplicitCopyAddrInst:
+      case SILInstructionKind::ExplicitCopyValueInst:
+        break; // Explicitly acknowledged copies are OK.
+      case SILInstructionKind::CopyAddrInst: {
+        if (!cast<CopyAddrInst>(inst)->isTakeOfSrc())
+          shouldDiagnose = true; // If it isn't a [take], it's a copy.
+        break;
+      }
+      case SILInstructionKind::LoadInst: {
+        // FIXME: we don't have an `explicit_load` and transparent functions can
+        //   end up bringing in a `load [copy]`. A better approach is needed to
+        //   handle transparent functions, in general, as rewriting them during
+        //   inlining of transparent functions is also not so great, as it
+        //   may hide a copy that semantically is there, but we happened to
+        //   tuck away in a transparent synthesized function, like those
+        //   synthesized getters!
+        //
+        // For now look to see if the load copy's only non-destroying users are
+        // explicit_copy's, as that would indicate the user has acknowledged it:
+        //
+        //  %y = load [copy] %x
+        //  %z = explicit_copy_value %y
+        //  destroy_value %y
+        //
+        // In all other cases, it's safer to diagnose.
+        //
+        auto load = cast<LoadInst>(inst);
+        if (load->getOwnershipQualifier() != LoadOwnershipQualifier::Copy)
+          break;
+
+        for (auto *use : load->getUsers()) {
+          if (!isa<ExplicitCopyAddrInst, ExplicitCopyValueInst,
+                   DestroyAddrInst, DestroyValueInst>(use)) {
+            shouldDiagnose = true;
+            break;
+          }
+        }
+        break;
+      }
+      default:
+        shouldDiagnose = true;
+        break;
+      }
+      if (shouldDiagnose) {
+        LLVM_DEBUG(llvm::dbgs()
+                   << "function " << inst->getFunction()->getName()
+                   << "\n has unexpected copying instruction: " << *inst);
+
+        // Try to come up with a useful diagnostic.
+
+        // First, identify what is being copied.
+        SILValue copied;
+        if (auto svi = dyn_cast<SingleValueInstruction>(inst)) {
+          copied = svi;
+        } else if (auto cai = dyn_cast<CopyAddrInst>(inst)) {
+          copied = cai->getSrc();
+        }
+
+        // Find a name for that copied thing.
+        std::optional<Identifier> name;
+        if (copied)
+          name = VariableNameInferrer::inferName(copied);
+
+        if (!name) {
+          // Emit a rudimentary diagnostic.
+          diagnose(loc, diag::manualownership_copy);
+          return false;
+        }
+
+        // Try to tailor the diagnostic based on usages.
+
+        // Simplistic check for whether this is a closure capture.
+        for (auto user : copied->getUsers()) {
+          if (isa<PartialApplyInst>(user)) {
+            LLVM_DEBUG(llvm::dbgs() << "captured by "<< *user);
+            diagnose(loc, diag::manualownership_copy_captured, name->get());
+            return false;
+          }
+        }
+
+        // There's no hope of borrowing access if there's a consuming use.
+        for (auto op : copied->getUses()) {
+          auto useKind = op->getOperandOwnership();
+
+          // Only some DestroyingConsume's, like 'store', are interesting.
+          if (useKind == OperandOwnership::ForwardingConsume
+              || isa<StoreInst>(op->getUser())) {
+            LLVM_DEBUG(llvm::dbgs() << "demanded by "<< *(op->getUser()));
+            diagnose(loc, diag::manualownership_copy_demanded, *name);
+            return false;
+          }
+        }
+
+        // Catch-all diagnostic for when we at least have the name.
+        diagnose(loc, diag::manualownership_copy_happened, *name);
+        return false;
+      }
+    }
+    return false;
+  }
+
   if (perfConstr == PerformanceConstraints::NoExistentials &&
       ((impact & RuntimeEffect::Existential) ||
        (impact & RuntimeEffect::ExistentialClassBound))) {
@@ -537,57 +515,6 @@ bool PerformanceDiagnostics::visitInst(SILInstruction *inst,
     return true;
   }
 
-  if (module.getOptions().EmbeddedSwift) {
-    // Explicitly don't detect RuntimeEffect::ExistentialClassBound - those are
-    // allowed in Embedded Swift.
-    if (impact & RuntimeEffect::Existential) {
-      PrettyStackTracePerformanceDiagnostics stackTrace("existential", inst);
-      if (impactType) {
-        diagnose(loc, diag::embedded_swift_existential_type, impactType.getASTType());
-      } else {
-        diagnose(loc, diag::embedded_swift_existential);
-      }
-      return true;
-    }
-
-    if (impact & RuntimeEffect::MetaData) {
-      if (isa<ReleaseValueInst>(inst)) {
-        // Move-only value types for which the deinit is not de-virtualized.
-        diagnose(loc, diag::embedded_swift_value_deinit, impactType.getASTType());
-        return true;
-      }
-      if (isa<KeyPathInst>(inst)) {
-        diagnose(loc, diag::embedded_swift_keypath);
-        return true;
-      }
-      if (isa<CheckedCastAddrBranchInst>(inst) || isa<UnconditionalCheckedCastAddrInst>(inst)) {
-        diagnose(loc, diag::embedded_swift_dynamic_cast);
-        return true;
-      }
-      if (!allowedMetadataUseInEmbeddedSwift(inst)) {
-        PrettyStackTracePerformanceDiagnostics stackTrace("metatype", inst);
-        if (impactType) {
-          diagnose(loc, diag::embedded_swift_metatype_type, impactType.getASTType());
-        } else {
-          diagnose(loc, diag::embedded_swift_metatype);
-        }
-        return true;
-      }
-    }
-
-    if (module.getOptions().NoAllocations) {
-      if (impact & RuntimeEffect::Allocating) {
-        PrettyStackTracePerformanceDiagnostics stackTrace("allocation", inst);
-        if (impactType) {
-          diagnose(loc, diag::embedded_swift_allocating_type, impactType.getASTType());
-        } else {
-          diagnose(loc, diag::embedded_swift_allocating);
-        }
-        return true;
-      }
-    }
-  }
-
   if (perfConstr == PerformanceConstraints::None ||
       perfConstr == PerformanceConstraints::NoExistentials ||
       perfConstr == PerformanceConstraints::NoObjCBridging)
@@ -789,7 +716,7 @@ class PerformanceDiagnosticsPass : public SILModuleTransform {
   void run() override {
     SILModule *module = getModule();
 
-    // Skip all performance/embedded diagnostics if asked. This is used from
+    // Skip all performance diagnostics if asked. This is used from
     // SourceKit to avoid reporting false positives when WMO is turned off for
     // indexing purposes.
     if (!module->getOptions().EnableWMORequiredDiagnostics) return;
@@ -833,7 +760,7 @@ class PerformanceDiagnosticsPass : public SILModuleTransform {
       }
     }
 
-    if (!annotatedFunctionsFound && !getModule()->getOptions().EmbeddedSwift)
+    if (!annotatedFunctionsFound)
       return;
 
     for (SILFunction &function : *module) {
@@ -845,57 +772,6 @@ class PerformanceDiagnosticsPass : public SILModuleTransform {
         diagnoser.checkNonAnnotatedFunction(&function);
       }
     }
-
-    if (getModule()->getOptions().EmbeddedSwift) {
-      // Run embedded Swift SIL checks for metatype/existential use, and
-      // allocation use (under -no-allocations mode). Try to start with public
-      // and exported functions to get better call tree information.
-      SmallVector<SILFunction *, 8> externallyVisibleFunctions;
-      SmallVector<SILFunction *, 8> vtableMembers;
-      SmallVector<SILFunction *, 8> others;
-      SmallVector<SILFunction *, 8> constructorsAndDestructors;
-
-      for (SILFunction &function : *module) {
-        // There might be SILFunctions without a location, e.g.
-        // swift_readAtKeyPath generated by SILGen for keypaths. It's okay to
-        // skip the ctor/dtor/method detection logic for those, such functions
-        // still end up in the "others" list and are still visited.
-        if (function.hasLocation()) {
-          auto func =
-              function.getLocation().getAsASTNode<AbstractFunctionDecl>();
-          if (func) {
-            if (isa<DestructorDecl>(func) || isa<ConstructorDecl>(func)) {
-              constructorsAndDestructors.push_back(&function);
-              continue;
-            }
-            if (getMethodDispatch(func) == MethodDispatch::Class) {
-              vtableMembers.push_back(&function);
-              continue;
-            }
-          }
-        }
-
-        if (function.isPossiblyUsedExternally()) {
-          externallyVisibleFunctions.push_back(&function);
-          continue;
-        }
-
-        others.push_back(&function);
-      }
-
-      for (SILFunction *function : externallyVisibleFunctions) {
-        diagnoser.visitFunctionEmbeddedSwift(function);
-      }
-      for (SILFunction *function : vtableMembers) {
-        diagnoser.visitFunctionEmbeddedSwift(function);
-      }
-      for (SILFunction *function : others) {
-        diagnoser.visitFunctionEmbeddedSwift(function);
-      }
-      for (SILFunction *function : constructorsAndDestructors) {
-        diagnoser.visitFunctionEmbeddedSwift(function);
-      }
-    }
   }
 };
 
diff --git a/lib/SILOptimizer/Mandatory/PredictableMemOpt.cpp b/lib/SILOptimizer/Mandatory/PredictableMemOpt.cpp
index 20e0211c91b5a..e62307f89703c 100644
--- a/lib/SILOptimizer/Mandatory/PredictableMemOpt.cpp
+++ b/lib/SILOptimizer/Mandatory/PredictableMemOpt.cpp
@@ -21,7 +21,7 @@
 #include "swift/SIL/BasicBlockBits.h"
 #include "swift/SIL/BasicBlockUtils.h"
 #include "swift/SIL/LinearLifetimeChecker.h"
-#include "swift/SIL/OSSALifetimeCompletion.h"
+#include "swift/SIL/OSSACompleteLifetime.h"
 #include "swift/SIL/OwnershipUtils.h"
 #include "swift/SIL/SILBuilder.h"
 #include "swift/SILOptimizer/PassManager/Passes.h"
@@ -2306,8 +2306,8 @@ void OptimizeDeadAlloc::removeDeadAllocation() {
   // post-dominating consuming use sets. This can happen if we have an enum that
   // is known dynamically none along a path. This is dynamically correct, but
   // can not be represented in OSSA so we insert these destroys along said path.
-  OSSALifetimeCompletion completion(TheMemory->getFunction(), domInfo,
-                                    deadEndBlocks);
+  OSSACompleteLifetime completion(TheMemory->getFunction(), domInfo,
+                                  deadEndBlocks);
 
   while (!valuesNeedingLifetimeCompletion.empty()) {
     auto optV = valuesNeedingLifetimeCompletion.pop_back_val();
@@ -2318,8 +2318,8 @@ void OptimizeDeadAlloc::removeDeadAllocation() {
     // don't end in unreachable. Force their lifetime to end immediately after
     // the last use instead.
     auto boundary = v->getType().isOrHasEnum()
-                        ? OSSALifetimeCompletion::Boundary::Liveness
-                        : OSSALifetimeCompletion::Boundary::Availability;
+                        ? OSSACompleteLifetime::Boundary::Liveness
+                        : OSSACompleteLifetime::Boundary::Availability;
     LLVM_DEBUG(llvm::dbgs() << "Completing lifetime of: ");
     LLVM_DEBUG(v->dump());
     completion.completeOSSALifetime(v, boundary);
@@ -2339,7 +2339,7 @@ SILValue OptimizeDeadAlloc::promoteMarkDepBase(
   }
   LLVM_DEBUG(llvm::dbgs() << "      To value: " << dependentValue);
   md->replaceAllUsesWith(dependentValue);
-  deleter.deleteIfDead(md);
+  deleter.forceDelete(md);
   return dependentValue;
 }
 
diff --git a/lib/SILOptimizer/Mandatory/RawSILInstLowering.cpp b/lib/SILOptimizer/Mandatory/RawSILInstLowering.cpp
index 24ccbb0842762..79e4a949e0141 100644
--- a/lib/SILOptimizer/Mandatory/RawSILInstLowering.cpp
+++ b/lib/SILOptimizer/Mandatory/RawSILInstLowering.cpp
@@ -180,88 +180,6 @@ static void emitInitAccessorInitialValueArgument(
                                     forProjections, forCleanup);
 }
 
-static void
-lowerAssignByWrapperInstruction(SILBuilderWithScope &b,
-                                AssignByWrapperInst *inst,
-                                llvm::SmallSetVector<SILValue, 8> &toDelete) {
-  LLVM_DEBUG(llvm::dbgs() << "  *** Lowering " << *inst << "\n");
-
-  ++numAssignRewritten;
-
-  SILValue src = inst->getSrc();
-  SILValue dest = inst->getDest();
-  SILLocation loc = inst->getLoc();
-  SILBuilderWithScope forCleanup(std::next(inst->getIterator()));
-  
-  switch (inst->getMode()) {
-    case AssignByWrapperInst::Unknown:
-      assert(b.getModule().getASTContext().hadError() &&
-             "assign_by_wrapper must have a valid mode");
-      // In case DefiniteInitialization already gave up with an error, just
-      // treat the assign_by_wrapper as an "init".
-      LLVM_FALLTHROUGH;
-    case AssignByWrapperInst::Initialization:
-    case AssignByWrapperInst::Assign: {
-      SILValue initFn = inst->getInitializer();
-      CanSILFunctionType fTy = initFn->getType().castTo<SILFunctionType>();
-      SILFunctionConventions convention(fTy, inst->getModule());
-      SmallVector<SILValue, 4> args;
-      if (convention.hasIndirectSILResults()) {
-        if (inst->getMode() == AssignByWrapperInst::Assign)
-          b.createDestroyAddr(loc, dest);
-
-        args.push_back(dest);
-        getAssignByWrapperArgs(args, src, convention, b, forCleanup);
-        b.createApply(loc, initFn, SubstitutionMap(), args);
-      } else {
-        getAssignByWrapperArgs(args, src, convention, b, forCleanup);
-        SILValue wrappedSrc =
-            b.createApply(loc, initFn, SubstitutionMap(), args);
-        if (inst->getMode() == AssignByWrapperInst::Initialization ||
-            inst->getDest()->getType().isTrivial(*inst->getFunction())) {
-          b.createTrivialStoreOr(loc, wrappedSrc, dest,
-                                 StoreOwnershipQualifier::Init);
-        } else {
-          b.createStore(loc, wrappedSrc, dest, StoreOwnershipQualifier::Assign);
-        }
-      }
-
-      // The unused partial_apply violates memory lifetime rules in case "self"
-      // is an inout. Therefore we cannot keep it as a dead closure to be
-      // cleaned up later. We have to delete it in this pass.
-      toDelete.insert(inst->getSetter());
-      
-      // Also the argument of the closure (which usually is a "load") has to be
-      // deleted to avoid memory lifetime violations.
-      auto *setterPA = dyn_cast<PartialApplyInst>(inst->getSetter());
-      if (setterPA && setterPA->getNumArguments() == 1)
-        toDelete.insert(setterPA->getArgument(0));
-      break;
-    }
-    case AssignByWrapperInst::AssignWrappedValue: {
-      SILValue setterFn = inst->getSetter();
-      CanSILFunctionType fTy = setterFn->getType().castTo<SILFunctionType>();
-      SILFunctionConventions convention(fTy, inst->getModule());
-      assert(!convention.hasIndirectSILResults());
-      SmallVector<SILValue, 4> args;
-      getAssignByWrapperArgs(args, src, convention, b, forCleanup);
-      b.createApply(loc, setterFn, SubstitutionMap(), args);
-
-      // The destination address is not used. Remove it if it is a dead access
-      // marker. This is important, because also the setter function contains
-      // access marker. In case those markers are dynamic it would cause a
-      // nested access violation.
-      if (isa<BeginAccessInst>(dest))
-        toDelete.insert(dest);
-        
-      // Again, we have to delete the unused dead closure.
-      toDelete.insert(inst->getInitializer());
-      break;
-    }
-  }
-  inst->eraseFromParent();
-}
-
 static void
 lowerAssignOrInitInstruction(SILBuilderWithScope &b,
                              AssignOrInitInst *inst,
@@ -279,27 +197,20 @@ lowerAssignOrInitInstruction(SILBuilderWithScope &b,
       assert(b.getModule().getASTContext().hadError() &&
              "assign_or_init must have a valid mode");
       // In case DefiniteInitialization already gave up with an error, just
-      // treat the assign_or_init as an "init".
+      // treat the assign_or_init with an "init" mode.
       LLVM_FALLTHROUGH;
     case AssignOrInitInst::Init: {
       SILValue initFn = inst->getInitializer();
       CanSILFunctionType fTy = initFn->getType().castTo<SILFunctionType>();
       SILFunctionConventions convention(fTy, inst->getModule());
 
-      auto selfValue = inst->getSelf();
-      auto isRefSelf = selfValue->getType().getASTType()->mayHaveSuperclass();
-
-      SILValue selfRef;
-      if (isRefSelf) {
-        selfRef = b.emitBeginBorrowOperation(loc, selfValue);
-      } else {
-        selfRef = b.createBeginAccess(loc, selfValue, SILAccessKind::Modify,
-                                      SILAccessEnforcement::Dynamic,
-                                      /*noNestedConflict=*/false,
-                                      /*fromBuiltin=*/false);
-      }
+      auto inLocalContext =
+          inst->getProperty()->getDeclContext()->isLocalContext();
+      auto selfOrLocalValue = inst->getSelfOrLocalOperand();
+      bool isRefSelf =
+          selfOrLocalValue->getType().getASTType()->mayHaveSuperclass();
 
-      auto emitFieldReference = [&](VarDecl *field,
+      auto emitFieldReference = [&](SILValue selfRef, VarDecl *field,
                                     bool emitDestroy = false) -> SILValue {
         SILValue fieldRef;
         if (isRefSelf) {
@@ -318,13 +229,36 @@ lowerAssignOrInitInstruction(SILBuilderWithScope &b,
 
       // First, emit all of the properties listed in `initializes`. They
       // are passed as indirect results.
-      {
-        auto toInitialize = inst->getInitializedProperties();
-        for (unsigned index : indices(toInitialize)) {
+      SILValue selfRef = nullptr;
+      bool needInsertEndAccess = false;
+      if (inLocalContext) {
+        // add the local projection which is for the _x backing local storage
+        arguments.push_back(selfOrLocalValue);
+      } else {
+        if (isRefSelf) {
+          selfRef = b.emitBeginBorrowOperation(loc, selfOrLocalValue);
+        } else if (isa<BeginAccessInst>(selfOrLocalValue)) {
+          // Don't insert an access scope if there is already one. This avoids
+          // inserting a dynamic access check when the parent is static (and therefore
+          // can be statically enforced).
+          selfRef = selfOrLocalValue;
+        } 
+        else {
+          selfRef =
+              b.createBeginAccess(loc, selfOrLocalValue, SILAccessKind::Modify,
+                                  SILAccessEnforcement::Dynamic,
+                                  /*noNestedConflict=*/false,
+                                  /*fromBuiltin=*/false);
+          needInsertEndAccess = true;
+        }
+
+        unsigned index = 0;
+        inst->forEachInitializedProperty([&](VarDecl *property) {
           arguments.push_back(emitFieldReference(
-              toInitialize[index],
+              selfRef, property,
               /*emitDestroy=*/inst->isPropertyAlreadyInitialized(index)));
-        }
+          index++;
+        });
       }
 
       // Now emit `initialValue` which is the only argument specified
@@ -334,15 +268,17 @@ lowerAssignOrInitInstruction(SILBuilderWithScope &b,
 
       // And finally, emit all of the `accesses` properties.
       for (auto *property : inst->getAccessedProperties())
-        arguments.push_back(emitFieldReference(property));
+        arguments.push_back(emitFieldReference(selfRef, property));
 
       b.createApply(loc, initFn, SubstitutionMap(), arguments);
 
-      if (isRefSelf) {
-        if (selfRef != selfValue)
-          b.emitEndBorrowOperation(loc, selfRef);
-      } else {
-        b.createEndAccess(loc, selfRef, /*aborted=*/false);
+      if (selfRef) {
+        if (isRefSelf) {
+          if (selfRef != selfOrLocalValue)
+            b.emitEndBorrowOperation(loc, selfRef);
+        } else if (needInsertEndAccess) {
+          b.createEndAccess(loc, selfRef, /*aborted=*/false);
+        }
       }
 
       // The unused partial_apply violates memory lifetime rules in case "self"
@@ -452,13 +388,6 @@ static bool lowerRawSILOperations(SILFunction &fn) {
         continue;
       }
 
-      if (auto *ai = dyn_cast<AssignByWrapperInst>(inst)) {
-        SILBuilderWithScope b(ai);
-        lowerAssignByWrapperInstruction(b, ai, toDelete);
-        changed = true;
-        continue;
-      }
-
       if (auto *ai = dyn_cast<AssignOrInitInst>(inst)) {
         SILBuilderWithScope b(ai);
         lowerAssignOrInitInstruction(b, ai, toDelete);
diff --git a/lib/SILOptimizer/Mandatory/SILGenCleanup.cpp b/lib/SILOptimizer/Mandatory/SILGenCleanup.cpp
index c61118536d728..40ee8c02f635f 100644
--- a/lib/SILOptimizer/Mandatory/SILGenCleanup.cpp
+++ b/lib/SILOptimizer/Mandatory/SILGenCleanup.cpp
@@ -21,7 +21,7 @@
 #include "swift/SIL/BasicBlockBits.h"
 #include "swift/SIL/BasicBlockDatastructures.h"
 #include "swift/SIL/BasicBlockUtils.h"
-#include "swift/SIL/OSSALifetimeCompletion.h"
+#include "swift/SIL/OSSACompleteLifetime.h"
 #include "swift/SIL/PrettyStackTrace.h"
 #include "swift/SIL/PrunedLiveness.h"
 #include "swift/SIL/SILInstruction.h"
@@ -110,7 +110,7 @@ struct SILGenCleanup : SILModuleTransform {
   bool completeOSSALifetimes(SILFunction *function);
   template <typename Range>
   bool completeLifetimesInRange(Range const &range,
-                                OSSALifetimeCompletion &completion,
+                                OSSACompleteLifetime &completion,
                                 BasicBlockSet &completed);
 };
 
@@ -267,9 +267,8 @@ bool SILGenCleanup::completeOSSALifetimes(SILFunction *function) {
   }
 
   bool changed = false;
-  OSSALifetimeCompletion completion(
-    function, /*DomInfo*/ nullptr, *deba,
-    OSSALifetimeCompletion::ExtendTrivialVariable);
+  OSSACompleteLifetime completion(function, /*DomInfo*/ nullptr, *deba,
+                                  OSSACompleteLifetime::ExtendTrivialVariable);
   BasicBlockSet completed(function);
   for (auto *root : roots) {
     if (root == function->getEntryBlock()) {
@@ -296,7 +295,7 @@ bool SILGenCleanup::completeOSSALifetimes(SILFunction *function) {
 
 template <typename Range>
 bool SILGenCleanup::completeLifetimesInRange(Range const &range,
-                                             OSSALifetimeCompletion &completion,
+                                             OSSACompleteLifetime &completion,
                                              BasicBlockSet &completed) {
   bool changed = false;
   for (auto *block : range) {
@@ -308,7 +307,7 @@ bool SILGenCleanup::completeLifetimesInRange(Range const &range,
       for (auto result : inst.getResults()) {
         LLVM_DEBUG(llvm::dbgs() << "completing " << result << "\n");
         if (completion.completeOSSALifetime(
-                result, OSSALifetimeCompletion::Boundary::Availability) ==
+                result, OSSACompleteLifetime::Boundary::Availability) ==
             LifetimeCompletion::WasCompleted) {
           LLVM_DEBUG(llvm::dbgs() << "\tcompleted!\n");
           changed = true;
@@ -319,7 +318,7 @@ bool SILGenCleanup::completeLifetimesInRange(Range const &range,
       LLVM_DEBUG(llvm::dbgs() << "completing " << *arg << "\n");
       assert(!arg->isReborrow() && "reborrows not legal at this SIL stage");
       if (completion.completeOSSALifetime(
-              arg, OSSALifetimeCompletion::Boundary::Availability) ==
+              arg, OSSACompleteLifetime::Boundary::Availability) ==
           LifetimeCompletion::WasCompleted) {
         LLVM_DEBUG(llvm::dbgs() << "\tcompleted!\n");
         changed = true;
diff --git a/lib/SILOptimizer/Mandatory/SendNonSendable.cpp b/lib/SILOptimizer/Mandatory/SendNonSendable.cpp
index 42df9bb5e92ac..4d4a2de656bd1 100644
--- a/lib/SILOptimizer/Mandatory/SendNonSendable.cpp
+++ b/lib/SILOptimizer/Mandatory/SendNonSendable.cpp
@@ -12,6 +12,8 @@
 
 #define DEBUG_TYPE "send-non-sendable"
 
+#include "swift/SIL/PrunedLiveness.h"
+
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/Concurrency.h"
 #include "swift/AST/DiagnosticsSIL.h"
@@ -149,17 +151,16 @@ static std::optional<SILDeclRef> getDeclRefForCallee(SILInstruction *inst) {
   }
 }
 
-static std::optional<std::pair<DescriptiveDeclKind, DeclName>>
-getSendingApplyCalleeInfo(SILInstruction *inst) {
+static std::optional<ValueDecl *> getSendingApplyCallee(SILInstruction *inst) {
   auto declRef = getDeclRefForCallee(inst);
   if (!declRef)
     return {};
 
   auto *decl = declRef->getDecl();
-  if (!decl || !decl->hasName())
+  if (!decl)
     return {};
 
-  return {{decl->getDescriptiveKind(), decl->getName()}};
+  return decl;
 }
 
 static Expr *inferArgumentExprFromApplyExpr(ApplyExpr *sourceApply,
@@ -642,6 +643,215 @@ class SendNonSendableImpl {
 
 } // namespace
 
+//===----------------------------------------------------------------------===//
+//                         MARK: Diagnostic Evaluator
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+struct DiagnosticEvaluator final
+    : PartitionOpEvaluatorBaseImpl<DiagnosticEvaluator> {
+  RegionAnalysisFunctionInfo *info;
+  SmallFrozenMultiMap<Operand *, RequireInst, 8>
+      &sendingOpToRequireInstMultiMap;
+
+  /// An error that we know how to emit verbatim without needing to preprocess.
+  ///
+  /// A contrasting case here is the use after send error where we need to pair
+  /// sending operands to require insts.
+  SmallVectorImpl<PartitionOpError> &foundVerbatimErrors;
+
+  DiagnosticEvaluator(Partition &workingPartition,
+                      RegionAnalysisFunctionInfo *info,
+                      SmallFrozenMultiMap<Operand *, RequireInst, 8>
+                          &sendingOpToRequireInstMultiMap,
+                      SmallVectorImpl<PartitionOpError> &foundVerbatimErrors,
+                      SendingOperandToStateMap &operandToStateMap)
+      : PartitionOpEvaluatorBaseImpl(
+            workingPartition, info->getOperandSetFactory(), operandToStateMap),
+        info(info),
+        sendingOpToRequireInstMultiMap(sendingOpToRequireInstMultiMap),
+        foundVerbatimErrors(foundVerbatimErrors) {}
+
+  void handleLocalUseAfterSend(LocalUseAfterSendError &&error) const {
+    const auto &partitionOp = *error.op;
+    REGIONBASEDISOLATION_LOG(error.print(llvm::dbgs(), info->getValueMap()));
+
+    // Ignore this if we are erroring on a mutable base of a Sendable value and
+    // if when we sent the value's region was not closure captured.
+    if (error.op->getOptions().containsOnly(
+            PartitionOp::Flag::RequireOfMutableBaseOfSendableValue) &&
+        !operandToStateMap.get(error.sendingOp).isClosureCaptured)
+      return;
+
+    sendingOpToRequireInstMultiMap.insert(
+        error.sendingOp, RequireInst::forUseAfterSend(partitionOp.getSourceInst()));
+  }
+
+  void handleInOutSendingNotInitializedAtExitError(
+      InOutSendingNotInitializedAtExitError &&error) const {
+    const PartitionOp &partitionOp = *error.op;
+    Operand *sendingOp = error.sendingOp;
+
+    REGIONBASEDISOLATION_LOG(error.print(llvm::dbgs(), info->getValueMap()));
+
+    sendingOpToRequireInstMultiMap.insert(
+        sendingOp, RequireInst::forInOutReinitializationNeeded(
+                       partitionOp.getSourceInst()));
+  }
+
+  void handleUnknownCodePattern(UnknownCodePatternError &&error) const {
+    const PartitionOp &op = *error.op;
+
+    if (shouldAbortOnUnknownPatternMatchError()) {
+      llvm::report_fatal_error(
+          "RegionIsolation: Aborting on unknown pattern match error");
+    }
+
+    diagnoseError(op.getSourceInst(),
+                  diag::regionbasedisolation_unknown_pattern);
+  }
+
+  void handleError(PartitionOpError &&error) {
+    switch (error.getKind()) {
+    case PartitionOpError::LocalUseAfterSend: {
+      return handleLocalUseAfterSend(
+          std::move(error).getLocalUseAfterSendError());
+    }
+    case PartitionOpError::InOutSendingNotDisconnectedAtExit:
+    case PartitionOpError::InOutSendingReturned:
+    case PartitionOpError::SentNeverSendable:
+    case PartitionOpError::AssignNeverSendableIntoSendingResult:
+    case PartitionOpError::NonSendableIsolationCrossingResult:
+      // We are going to process these later... but dump so we can see that we
+      // handled an error here. The rest of the explicit handlers will dump as
+      // appropriate if they want to emit an error here (some will squelch the
+      // error).
+      REGIONBASEDISOLATION_LOG(error.print(llvm::dbgs(), info->getValueMap()));
+      foundVerbatimErrors.emplace_back(std::move(error));
+      return;
+    case PartitionOpError::InOutSendingNotInitializedAtExit: {
+      return handleInOutSendingNotInitializedAtExitError(
+          std::move(error).getInOutSendingNotInitializedAtExitError());
+    }
+    case PartitionOpError::UnknownCodePattern: {
+      return handleUnknownCodePattern(
+          std::move(error).getUnknownCodePatternError());
+    }
+    }
+    llvm_unreachable("Covered switch isn't covered?!");
+  }
+
+  bool isActorDerived(Element element) const {
+    return info->getValueMap().getIsolationRegion(element).isActorIsolated();
+  }
+
+  /// If \p element's representative is an indirect out parameter, return
+  /// that parameter.
+  SILValue getIndirectOutParameter(Element element) const {
+    auto rep = info->getValueMap().getRepresentativeValue(element);
+    if (!rep)
+      return {};
+    if (auto value = dyn_cast_or_null<SILFunctionArgument>(rep.maybeGetValue());
+        value && value->getArgumentConvention().isIndirectOutParameter())
+      return value;
+    return {};
+  }
+
+  SILValue getInOutSendingParameter(Element elt) const {
+    auto rep = info->getValueMap().getRepresentativeValue(elt);
+    if (!rep)
+      return {};
+    if (auto value = dyn_cast_or_null<SILFunctionArgument>(rep.maybeGetValue());
+        value && value->getArgumentConvention().isInoutConvention() &&
+        value->isSending())
+      return value;
+    return {};
+  }
+
+  bool isTaskIsolatedDerived(Element element) const {
+    return info->getValueMap().getIsolationRegion(element).isTaskIsolated();
+  }
+
+  SILIsolationInfo::Kind hasSpecialDerivation(Element element) const {
+    return info->getValueMap().getIsolationRegion(element).getKind();
+  }
+
+  SILIsolationInfo getIsolationRegionInfo(Element element) const {
+    return info->getValueMap().getIsolationRegion(element);
+  }
+
+  /// Only return an element if we are already tracking value and it is
+  /// non-Sendable.
+  ///
+  /// TODO: Can we return only
+  std::optional<Element> getElement(SILValue value) const {
+    auto trackableValue = info->getValueMap().getTrackableValue(value);
+    if (trackableValue.value.isSendable())
+      return {};
+    return trackableValue.value.getID();
+  }
+
+  SILValue getRepresentative(SILValue value) const {
+    return info->getValueMap()
+        .getTrackableValue(value)
+        .value.getRepresentative()
+        .maybeGetValue();
+  }
+
+  RepresentativeValue getRepresentativeValue(Element element) const {
+    return info->getValueMap().getRepresentativeValue(element);
+  }
+
+  bool isClosureCaptured(Element element, Operand *op) const {
+    auto value = info->getValueMap().maybeGetRepresentative(element);
+    if (!value)
+      return false;
+    return info->isClosureCaptured(value, op);
+  }
+};
+
+} // namespace
+
+void SendNonSendableImpl::runDiagnosticEvaluator() {
+  // Then for each block...
+  REGIONBASEDISOLATION_LOG(llvm::dbgs() << "Walking blocks for diagnostics.\n");
+  for (auto [block, blockState] : info->getRange()) {
+    REGIONBASEDISOLATION_LOG(llvm::dbgs()
+                             << "|--> Block bb" << block.getDebugID() << "\n");
+
+    if (!blockState.getLiveness()) {
+      REGIONBASEDISOLATION_LOG(llvm::dbgs() << "Dead block... skipping!\n");
+      continue;
+    }
+
+    REGIONBASEDISOLATION_LOG(
+        llvm::dbgs() << "Entry Partition: ";
+        blockState.getEntryPartition().print(llvm::dbgs()));
+
+    // Grab its entry partition and setup an evaluator for the partition that
+    // has callbacks that emit diagnsotics...
+    Partition workingPartition = blockState.getEntryPartition();
+    DiagnosticEvaluator eval(
+        workingPartition, info, sendingOpToRequireInstMultiMap,
+        foundVerbatimErrors, info->getSendingOperandToStateMap());
+
+    // And then evaluate all of our partition ops on the entry partition.
+    for (auto &partitionOp : blockState.getPartitionOps()) {
+      eval.apply(partitionOp);
+    }
+
+    REGIONBASEDISOLATION_LOG(llvm::dbgs() << "Exit Partition: ";
+                             workingPartition.print(llvm::dbgs()));
+  }
+
+  REGIONBASEDISOLATION_LOG(llvm::dbgs()
+                           << "Finished walking blocks for diagnostics.\n");
+
+  // Now that we have found all of our sendingInsts/Requires emit errors.
+  sendingOpToRequireInstMultiMap.setFrozen();
+}
+
 //===----------------------------------------------------------------------===//
 //                MARK: UseAfterSend Diagnostic Inference
 //===----------------------------------------------------------------------===//
@@ -672,10 +882,9 @@ class UseAfterSendDiagnosticEmitter {
         getFunction());
   }
 
-  /// If we can find a callee decl name, return that. None otherwise.
-  std::optional<std::pair<DescriptiveDeclKind, DeclName>>
-  getSendingCalleeInfo() const {
-    return getSendingApplyCalleeInfo(sendingOp->getUser());
+  /// Attempts to retrieve and return the callee declaration.
+  std::optional<const ValueDecl *> getSendingCallee() const {
+    return getSendingApplyCallee(sendingOp->getUser());
   }
 
   void
@@ -688,26 +897,25 @@ class UseAfterSendDiagnosticEmitter {
         .limitBehaviorIf(getBehaviorLimit());
 
     // Then emit the note with greater context.
-    SmallString<64> descriptiveKindStr;
-    {
-      if (!namedValuesIsolationInfo.isDisconnected()) {
-        llvm::raw_svector_ostream os(descriptiveKindStr);
-        namedValuesIsolationInfo.printForDiagnostics(os);
-        os << ' ';
-      }
-    }
-
-    if (auto calleeInfo = getSendingCalleeInfo()) {
+    auto descriptiveKindStr =
+        namedValuesIsolationInfo.printForDiagnostics(getFunction());
+    auto calleeIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCalleeIsolation());
+    auto callerIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCallerIsolation());
+
+    bool isDisconnected = namedValuesIsolationInfo.isDisconnected();
+    if (auto callee = getSendingCallee()) {
       diagnoseNote(
           loc, diag::regionbasedisolation_named_info_send_yields_race_callee,
-          name, descriptiveKindStr, isolationCrossing.getCalleeIsolation(),
-          calleeInfo->first, calleeInfo->second,
-          isolationCrossing.getCallerIsolation());
+          isDisconnected, name, descriptiveKindStr, calleeIsolationStr,
+          callee.value(), callerIsolationStr);
     } else {
       diagnoseNote(loc, diag::regionbasedisolation_named_info_send_yields_race,
-                   name, descriptiveKindStr,
-                   isolationCrossing.getCalleeIsolation(),
-                   isolationCrossing.getCallerIsolation());
+                   isDisconnected, name, descriptiveKindStr, calleeIsolationStr,
+                   callerIsolationStr);
     }
     emitRequireInstDiagnostics();
   }
@@ -716,27 +924,27 @@ class UseAfterSendDiagnosticEmitter {
   emitNamedIsolationCrossingError(SILLocation loc, Identifier name,
                                   SILIsolationInfo namedValuesIsolationInfo,
                                   ApplyIsolationCrossing isolationCrossing,
-                                  DeclName calleeDeclName,
-                                  DescriptiveDeclKind calleeDeclKind) {
+                                  const ValueDecl *callee) {
     // Emit the short error.
     diagnoseError(loc, diag::regionbasedisolation_named_send_yields_race, name)
         .highlight(loc.getSourceRange())
         .limitBehaviorIf(getBehaviorLimit());
 
     // Then emit the note with greater context.
-    SmallString<64> descriptiveKindStr;
-    {
-      if (!namedValuesIsolationInfo.isDisconnected()) {
-        llvm::raw_svector_ostream os(descriptiveKindStr);
-        namedValuesIsolationInfo.printForDiagnostics(os);
-        os << ' ';
-      }
-    }
+    auto descriptiveKindStr =
+        namedValuesIsolationInfo.printForDiagnostics(getFunction());
+    auto calleeIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCalleeIsolation());
+    auto callerIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCallerIsolation());
+    bool isDisconnected = namedValuesIsolationInfo.isDisconnected();
 
-    diagnoseNote(
-        loc, diag::regionbasedisolation_named_info_send_yields_race_callee,
-        name, descriptiveKindStr, isolationCrossing.getCalleeIsolation(),
-        calleeDeclKind, calleeDeclName, isolationCrossing.getCallerIsolation());
+    diagnoseNote(loc,
+                 diag::regionbasedisolation_named_info_send_yields_race_callee,
+                 isDisconnected, name, descriptiveKindStr, calleeIsolationStr,
+                 callee, callerIsolationStr);
     emitRequireInstDiagnostics();
   }
 
@@ -759,15 +967,20 @@ class UseAfterSendDiagnosticEmitter {
         .highlight(loc.getSourceRange())
         .limitBehaviorIf(getBehaviorLimit());
 
-    if (auto calleeInfo = getSendingCalleeInfo()) {
+    auto calleeIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCalleeIsolation());
+    auto callerIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCallerIsolation());
+
+    if (auto callee = getSendingCallee()) {
       diagnoseNote(loc, diag::regionbasedisolation_type_use_after_send_callee,
-                   inferredType, isolationCrossing.getCalleeIsolation(),
-                   calleeInfo->first, calleeInfo->second,
-                   isolationCrossing.getCallerIsolation());
+                   inferredType, calleeIsolationStr, callee.value(),
+                   callerIsolationStr);
     } else {
       diagnoseNote(loc, diag::regionbasedisolation_type_use_after_send,
-                   inferredType, isolationCrossing.getCalleeIsolation(),
-                   isolationCrossing.getCallerIsolation());
+                   inferredType, calleeIsolationStr, callerIsolationStr);
     }
     emitRequireInstDiagnostics();
   }
@@ -793,10 +1006,10 @@ class UseAfterSendDiagnosticEmitter {
                   inferredType)
         .highlight(loc.getSourceRange())
         .limitBehaviorIf(getBehaviorLimit());
-    if (auto calleeInfo = getSendingCalleeInfo()) {
+    if (auto callee = getSendingCallee()) {
       diagnoseNote(loc,
                    diag::regionbasedisolation_typed_use_after_sending_callee,
-                   inferredType, calleeInfo->first, calleeInfo->second);
+                   inferredType, callee.value());
     } else {
       diagnoseNote(loc, diag::regionbasedisolation_typed_use_after_sending,
                    inferredType);
@@ -813,19 +1026,19 @@ class UseAfterSendDiagnosticEmitter {
         .highlight(loc.getSourceRange())
         .limitBehaviorIf(getBehaviorLimit());
 
-    SmallString<64> descriptiveKindStr;
-    {
-      if (!namedValuesIsolationInfo.isDisconnected()) {
-        llvm::raw_svector_ostream os(descriptiveKindStr);
-        namedValuesIsolationInfo.printForDiagnostics(os);
-        os << ' ';
-      }
-    }
-
-    diagnoseNote(
-        loc, diag::regionbasedisolation_named_isolated_closure_yields_race,
-        descriptiveKindStr, name, isolationCrossing.getCalleeIsolation(),
-        isolationCrossing.getCallerIsolation())
+    auto descriptiveKindStr =
+        namedValuesIsolationInfo.printForDiagnostics(getFunction());
+    auto calleeIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCalleeIsolation());
+    auto callerIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCallerIsolation());
+    bool isDisconnected = namedValuesIsolationInfo.isDisconnected();
+    diagnoseNote(loc,
+                 diag::regionbasedisolation_named_isolated_closure_yields_race,
+                 isDisconnected, descriptiveKindStr, name, calleeIsolationStr,
+                 callerIsolationStr)
         .highlight(loc.getSourceRange());
     emitRequireInstDiagnostics();
   }
@@ -837,10 +1050,17 @@ class UseAfterSendDiagnosticEmitter {
                   inferredType)
         .highlight(loc.getSourceRange())
         .limitBehaviorIf(getBehaviorLimit());
+
+    auto calleeIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCalleeIsolation());
+    auto callerIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCallerIsolation());
+
     diagnoseNote(loc,
                  diag::regionbasedisolation_type_isolated_capture_yields_race,
-                 inferredType, isolationCrossing.getCalleeIsolation(),
-                 isolationCrossing.getCallerIsolation());
+                 inferredType, calleeIsolationStr, callerIsolationStr);
     emitRequireInstDiagnostics();
   }
 
@@ -1078,7 +1298,7 @@ struct UseAfterSendDiagnosticInferrer::AutoClosureWalker : ASTWalker {
           continue;
         }
 
-        // Otherwise, we are calling an actor isolated function in the async
+        // Otherwise, we are calling an actor-isolated function in the async
         // let. Emit a better error.
 
         // See if we can find a valueDecl/name for our callee so we can
@@ -1106,8 +1326,7 @@ struct UseAfterSendDiagnosticInferrer::AutoClosureWalker : ASTWalker {
           if (valueDecl->hasName()) {
             foundTypeInfo.diagnosticEmitter.emitNamedIsolationCrossingError(
                 foundTypeInfo.baseLoc, targetDecl->getBaseIdentifier(),
-                targetDeclIsolationInfo, *isolationCrossing,
-                valueDecl->getName(), valueDecl->getDescriptiveKind());
+                targetDeclIsolationInfo, *isolationCrossing, valueDecl);
             continue;
           }
 
@@ -1304,6 +1523,18 @@ class SendNeverSentDiagnosticEmitter {
   ~SendNeverSentDiagnosticEmitter() {
     if (!emittedErrorDiagnostic) {
       emitUnknownPatternError();
+    } else if (auto proto = isolationRegionInfo.getIsolationInfo()
+                   .getIsolatedConformance()) {
+       // If the diagnostic comes from a (potentially) isolated conformance,
+       // add a note saying so and indicating where the isolated conformance
+       // can come in.
+       if (auto value = isolationRegionInfo.getIsolationInfo().getIsolatedValue()) {
+         if (auto loc = value.getLoc()) {
+           diagnoseNote(
+               loc, diag::regionbasedisolation_isolated_conformance_introduced,
+               proto);
+         }
+       }
     }
   }
 
@@ -1318,14 +1549,20 @@ class SendNeverSentDiagnosticEmitter {
   }
 
   std::optional<DiagnosticBehavior> getBehaviorLimit() const {
+    // If the failure is due to an isolated conformance, downgrade the error
+    // to a warning prior to Swift 7.
+    if (isolationRegionInfo.getIsolationInfo().getIsolatedConformance() &&
+        !sendingOperand->get()->getType().getASTType()->getASTContext().LangOpts
+          .isSwiftVersionAtLeast(7))
+      return DiagnosticBehavior::Warning;
+
     return sendingOperand->get()->getType().getConcurrencyDiagnosticBehavior(
         getOperand()->getFunction());
   }
 
-  /// If we can find a callee decl name, return that. None otherwise.
-  std::optional<std::pair<DescriptiveDeclKind, DeclName>>
-  getSendingCalleeInfo() const {
-    return getSendingApplyCalleeInfo(sendingOperand->getUser());
+  /// Attempts to retrieve and return the callee declaration.
+  std::optional<const ValueDecl *> getSendingCallee() const {
+    return getSendingApplyCallee(sendingOperand->getUser());
   }
 
   SILLocation getLoc() const { return sendingOperand->getUser()->getLoc(); }
@@ -1359,40 +1596,41 @@ class SendNeverSentDiagnosticEmitter {
         .highlight(loc.getSourceRange())
         .limitBehaviorIf(getBehaviorLimit());
 
-    SmallString<64> descriptiveKindStr;
-    {
-      llvm::raw_svector_ostream os(descriptiveKindStr);
-      getIsolationRegionInfo().printForDiagnostics(os);
-    }
+    auto descriptiveKindStr =
+        getIsolationRegionInfo().printForDiagnostics(getFunction());
+    auto calleeIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), crossing.getCalleeIsolation());
 
-    if (auto calleeInfo = getSendingCalleeInfo()) {
+    if (auto callee = getSendingCallee()) {
       diagnoseNote(
           loc,
           diag::regionbasedisolation_typed_sendneversendable_via_arg_callee,
-          descriptiveKindStr, inferredType, crossing.getCalleeIsolation(),
-          calleeInfo->first, calleeInfo->second);
+          descriptiveKindStr, inferredType, calleeIsolationStr, callee.value());
     } else {
-      diagnoseNote(
-          loc, diag::regionbasedisolation_typed_sendneversendable_via_arg,
-          descriptiveKindStr, inferredType, crossing.getCalleeIsolation());
+      diagnoseNote(loc,
+                   diag::regionbasedisolation_typed_sendneversendable_via_arg,
+                   descriptiveKindStr, inferredType, calleeIsolationStr);
     }
   }
 
   void emitNamedFunctionArgumentClosure(SILLocation loc, Identifier name,
                                         ApplyIsolationCrossing crossing) {
     emitNamedOnlyError(loc, name);
-    SmallString<64> descriptiveKindStr;
-    {
-      if (!getIsolationRegionInfo().isDisconnected()) {
-        llvm::raw_svector_ostream os(descriptiveKindStr);
-        getIsolationRegionInfo().printForDiagnostics(os);
-        os << ' ';
-      }
-    }
+
+    auto descriptiveKindStr =
+        getIsolationRegionInfo().printForDiagnostics(getFunction());
+    auto calleeIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), crossing.getCalleeIsolation());
+    auto callerIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), crossing.getCallerIsolation());
+    bool isDisconnected = getIsolationRegionInfo().isDisconnected();
     diagnoseNote(loc,
                  diag::regionbasedisolation_named_isolated_closure_yields_race,
-                 descriptiveKindStr, name, crossing.getCalleeIsolation(),
-                 crossing.getCallerIsolation())
+                 isDisconnected, descriptiveKindStr, name, calleeIsolationStr,
+                 callerIsolationStr)
         .highlight(loc.getSourceRange());
   }
 
@@ -1403,17 +1641,13 @@ class SendNeverSentDiagnosticEmitter {
         .highlight(loc.getSourceRange())
         .limitBehaviorIf(getBehaviorLimit());
 
-    SmallString<64> descriptiveKindStr;
-    {
-      llvm::raw_svector_ostream os(descriptiveKindStr);
-      getIsolationRegionInfo().printForDiagnostics(os);
-    }
+    auto descriptiveKindStr =
+        getIsolationRegionInfo().printForDiagnostics(getFunction());
 
-    if (auto calleeInfo = getSendingCalleeInfo()) {
+    if (auto callee = getSendingCallee()) {
       diagnoseNote(
           loc, diag::regionbasedisolation_typed_tns_passed_to_sending_callee,
-          descriptiveKindStr, inferredType, calleeInfo->first,
-          calleeInfo->second);
+          descriptiveKindStr, inferredType, callee.value());
     } else {
       diagnoseNote(loc, diag::regionbasedisolation_typed_tns_passed_to_sending,
                    descriptiveKindStr, inferredType);
@@ -1426,11 +1660,8 @@ class SendNeverSentDiagnosticEmitter {
   void emitClosureErrorWithCapturedActor(Operand *partialApplyOp,
                                          Operand *actualUse,
                                          SILArgument *fArg) {
-    SmallString<64> descriptiveKindStr;
-    {
-      llvm::raw_svector_ostream os(descriptiveKindStr);
-      getIsolationRegionInfo().getIsolationInfo().printForCodeDiagnostic(os);
-    }
+    auto descriptiveKindStr =
+        getIsolationRegionInfo().printForCodeDiagnostic(getFunction());
 
     diagnoseError(partialApplyOp,
                   diag::regionbasedisolation_typed_tns_passed_sending_closure,
@@ -1438,11 +1669,8 @@ class SendNeverSentDiagnosticEmitter {
         .limitBehaviorIf(getDiagnosticBehaviorLimitForOperands(
             actualUse->getFunction(), {actualUse}));
 
-    descriptiveKindStr.clear();
-    {
-      llvm::raw_svector_ostream os(descriptiveKindStr);
-      getIsolationRegionInfo().getIsolationInfo().printForDiagnostics(os);
-    }
+    descriptiveKindStr =
+        getIsolationRegionInfo().printForDiagnostics(getFunction());
     diagnoseNote(actualUse, diag::regionbasedisolation_closure_captures_actor,
                  fArg->getDecl()->getName(), descriptiveKindStr);
   }
@@ -1457,11 +1685,8 @@ class SendNeverSentDiagnosticEmitter {
   void emitSendingClosureParamDirectlyIsolated(Operand *partialApplyOp,
                                                Operand *actualUse,
                                                SILArgument *fArg) {
-    SmallString<64> descriptiveKindStr;
-    {
-      llvm::raw_svector_ostream os(descriptiveKindStr);
-      getIsolationRegionInfo().getIsolationInfo().printForCodeDiagnostic(os);
-    }
+    auto descriptiveKindStr =
+        getIsolationRegionInfo().printForCodeDiagnostic(getFunction());
 
     diagnoseError(partialApplyOp,
                   diag::regionbasedisolation_typed_tns_passed_sending_closure,
@@ -1475,8 +1700,7 @@ class SendNeverSentDiagnosticEmitter {
           fArg->getType().is<SILBoxType>()) {
         auto diag = diag::
             regionbasedisolation_typed_tns_passed_to_sending_closure_helper_have_boxed_value_task_isolated;
-        diagnoseNote(actualUse, diag, fArg->getDecl()->getName(),
-                     fArg->getDecl()->getDescriptiveKind());
+        diagnoseNote(actualUse, diag, fArg->getDecl());
         return;
       }
 
@@ -1486,11 +1710,8 @@ class SendNeverSentDiagnosticEmitter {
       return;
     }
 
-    descriptiveKindStr.clear();
-    {
-      llvm::raw_svector_ostream os(descriptiveKindStr);
-      getIsolationRegionInfo().printForDiagnostics(os);
-    }
+    descriptiveKindStr =
+        getIsolationRegionInfo().printForDiagnostics(getFunction());
 
     auto diag = diag::
         regionbasedisolation_typed_tns_passed_to_sending_closure_helper_have_value;
@@ -1507,11 +1728,8 @@ class SendNeverSentDiagnosticEmitter {
       return;
     }
 
-    SmallString<64> descriptiveKindStr;
-    {
-      llvm::raw_svector_ostream os(descriptiveKindStr);
-      getIsolationRegionInfo()->printForCodeDiagnostic(os);
-    }
+    auto descriptiveKindStr =
+        getIsolationRegionInfo()->printForCodeDiagnostic(getFunction());
 
     auto emitMainError = [&] {
       auto behaviorLimit = getDiagnosticBehaviorLimitForOperands(
@@ -1543,11 +1761,8 @@ class SendNeverSentDiagnosticEmitter {
       }
 
       emitMainError();
-      descriptiveKindStr.clear();
-      {
-        llvm::raw_svector_ostream os(descriptiveKindStr);
-        getIsolationRegionInfo().printForDiagnostics(os);
-      }
+      descriptiveKindStr =
+          getIsolationRegionInfo().printForDiagnostics(getFunction());
       auto diag = diag::
           regionbasedisolation_typed_tns_passed_to_sending_closure_helper_have_value_region;
       diagnoseNote(actualUseInfo->first, diag, descriptiveKindStr,
@@ -1588,76 +1803,54 @@ class SendNeverSentDiagnosticEmitter {
            "Should never be disconnected?!");
     emitNamedOnlyError(loc, name);
 
-    SmallString<64> descriptiveKindStr;
-    {
-      llvm::raw_svector_ostream os(descriptiveKindStr);
-      getIsolationRegionInfo().printForDiagnostics(os);
-    }
+    auto descriptiveKindStr =
+        getIsolationRegionInfo().printForDiagnostics(getFunction());
 
     diagnoseNote(loc, diag::regionbasedisolation_named_send_nt_asynclet_capture,
-                 name, descriptiveKindStr)
-        .limitBehaviorIf(getBehaviorLimit());
+                 name, descriptiveKindStr);
   }
 
   void emitNamedIsolation(SILLocation loc, Identifier name,
                           ApplyIsolationCrossing isolationCrossing) {
     emitNamedOnlyError(loc, name);
-    SmallString<64> descriptiveKindStr;
-    SmallString<64> descriptiveKindStrWithSpace;
-    {
-      if (!getIsolationRegionInfo().isDisconnected()) {
-        {
-          llvm::raw_svector_ostream os(descriptiveKindStr);
-          getIsolationRegionInfo().printForDiagnostics(os);
-        }
-        descriptiveKindStrWithSpace = descriptiveKindStr;
-        descriptiveKindStrWithSpace.push_back(' ');
-      }
-    }
-    if (auto calleeInfo = getSendingCalleeInfo()) {
+
+    auto descriptiveKindStr =
+        getIsolationRegionInfo().printForDiagnostics(getFunction());
+    auto calleeIsolationStr =
+        SILIsolationInfo::printActorIsolationForDiagnostics(
+            getFunction(), isolationCrossing.getCalleeIsolation());
+    bool isDisconnected = getIsolationRegionInfo().isDisconnected();
+
+    if (auto callee = getSendingCallee()) {
       diagnoseNote(loc,
                    diag::regionbasedisolation_named_send_never_sendable_callee,
-                   name, descriptiveKindStrWithSpace,
-                   isolationCrossing.getCalleeIsolation(), calleeInfo->first,
-                   calleeInfo->second, descriptiveKindStr);
+                   isDisconnected, name, descriptiveKindStr, calleeIsolationStr,
+                   callee.value(), descriptiveKindStr);
     } else {
       diagnoseNote(loc, diag::regionbasedisolation_named_send_never_sendable,
-                   name, descriptiveKindStrWithSpace,
-                   isolationCrossing.getCalleeIsolation(), descriptiveKindStr);
+                   isDisconnected, name, descriptiveKindStr, calleeIsolationStr,
+                   descriptiveKindStr);
     }
   }
 
   void emitNamedSendingNeverSendableToSendingParam(SILLocation loc,
                                                    Identifier varName) {
     emitNamedOnlyError(loc, varName);
-    SmallString<64> descriptiveKindStr;
-    {
-      if (!getIsolationRegionInfo().isDisconnected()) {
-        llvm::raw_svector_ostream os(descriptiveKindStr);
-        getIsolationRegionInfo().printForDiagnostics(os);
-        os << ' ';
-      }
-    }
+
+    auto descriptiveKindStr =
+        getIsolationRegionInfo().printForDiagnostics(getFunction());
+    bool isDisconnected = getIsolationRegionInfo().isDisconnected();
     auto diag = diag::regionbasedisolation_named_send_into_sending_param;
-    diagnoseNote(loc, diag, descriptiveKindStr, varName);
+    diagnoseNote(loc, diag, isDisconnected, descriptiveKindStr, varName);
   }
 
   void emitNamedSendingReturn(SILLocation loc, Identifier varName) {
     emitNamedOnlyError(loc, varName);
-    SmallString<64> descriptiveKindStr;
-    SmallString<64> descriptiveKindStrWithSpace;
-    {
-      if (!getIsolationRegionInfo().isDisconnected()) {
-        {
-          llvm::raw_svector_ostream os(descriptiveKindStr);
-          getIsolationRegionInfo().printForDiagnostics(os);
-        }
-        descriptiveKindStrWithSpace = descriptiveKindStr;
-        descriptiveKindStrWithSpace.push_back(' ');
-      }
-    }
+    auto descriptiveKindStr =
+        getIsolationRegionInfo().printForDiagnostics(getFunction());
+    bool isDisconnected = getIsolationRegionInfo().isDisconnected();
     auto diag = diag::regionbasedisolation_named_nosend_send_into_result;
-    diagnoseNote(loc, diag, descriptiveKindStrWithSpace, varName,
+    diagnoseNote(loc, diag, isDisconnected, descriptiveKindStr, varName,
                  descriptiveKindStr);
   }
 
@@ -1752,7 +1945,7 @@ class SentNeverSendableDiagnosticInferrer {
   getIsolatedValuePartialApplyIndex(PartialApplyInst *pai,
                                     SILValue isolatedValue) {
     for (auto &paiOp : ApplySite(pai).getArgumentOperands()) {
-      if (valueMap.getTrackableValue(paiOp.get()).getRepresentative() ==
+      if (valueMap.getTrackableValue(paiOp.get()).value.getRepresentative() ==
           isolatedValue) {
         return ApplySite(pai).getASTAppliedArgIndex(paiOp);
       }
@@ -1836,13 +2029,13 @@ bool SentNeverSendableDiagnosticInferrer::initForSendingPartialApply(
     // If our value's rep is task isolated or is the dynamic isolated
     // value... then we are done. This is a 'correct' error value to emit.
     auto trackableValue = valueMap.getTrackableValue(sendingPAIOp.get());
-    if (trackableValue.isSendable())
+    if (trackableValue.value.isSendable())
       continue;
 
-    auto rep = trackableValue.getRepresentative().maybeGetValue();
+    auto rep = trackableValue.value.getRepresentative().maybeGetValue();
     nonSendableOps.push_back(&sendingPAIOp);
 
-    if (trackableValue.getIsolationRegionInfo().isTaskIsolated() ||
+    if (trackableValue.value.getIsolationRegionInfo().isTaskIsolated() ||
         rep == maybeIsolatedValue) {
       if (auto capturedValue = findClosureUse(&sendingPAIOp)) {
         diagnosticEmitter.emitSendingClosureParamDirectlyIsolated(
@@ -1866,30 +2059,23 @@ bool SentNeverSendableDiagnosticInferrer::initForSendingPartialApply(
 bool SentNeverSendableDiagnosticInferrer::initForIsolatedPartialApply(
     Operand *op, AbstractClosureExpr *ace,
     std::optional<ActorIsolation> actualCallerIsolation) {
-  SmallVector<std::tuple<CapturedValue, unsigned, ApplyIsolationCrossing>, 8>
-      foundCapturedIsolationCrossing;
-  ace->getIsolationCrossing(foundCapturedIsolationCrossing);
-  if (foundCapturedIsolationCrossing.empty())
+  auto diagnosticPair = findClosureUse(op);
+  if (!diagnosticPair)
     return false;
 
-  // We use getASTAppliedArgIndex instead of getAppliedArgIndex to ensure that
-  // we ignore for our indexing purposes any implicit initial parameters like
-  // isolated(any).
-  unsigned opIndex = ApplySite(op->getUser()).getASTAppliedArgIndex(*op);
-  for (auto &p : foundCapturedIsolationCrossing) {
-    if (std::get<1>(p) == opIndex) {
-      auto loc = RegularLocation(std::get<0>(p).getLoc());
-      auto crossing = std::get<2>(p);
-      auto declIsolation = crossing.getCallerIsolation();
-      auto closureIsolation = crossing.getCalleeIsolation();
-      if (!bool(declIsolation) && actualCallerIsolation) {
-        declIsolation = *actualCallerIsolation;
-      }
-      diagnosticEmitter.emitNamedFunctionArgumentClosure(
-          loc, std::get<0>(p).getDecl()->getBaseIdentifier(),
-          ApplyIsolationCrossing(declIsolation, closureIsolation));
-      return true;
-    }
+  auto *diagnosticOp = diagnosticPair->first;
+
+  ApplyIsolationCrossing crossing(
+      *op->getFunction()->getActorIsolation(),
+      *diagnosticOp->getFunction()->getActorIsolation());
+
+  // We do not need to worry about failing to infer a name here since we are
+  // going to be returning some form of a SILFunctionArgument which is always
+  // easy to find a name for.
+  if (auto rootValueAndName = inferNameAndRootHelper(op->get())) {
+    diagnosticEmitter.emitNamedFunctionArgumentClosure(
+        diagnosticOp->getUser()->getLoc(), rootValueAndName->first, crossing);
+    return true;
   }
 
   return false;
@@ -1979,7 +2165,6 @@ bool SentNeverSendableDiagnosticInferrer::run() {
           return true;
 
         // See if we can infer a name from the value.
-        SmallString<64> resultingName;
         if (auto varName = inferNameHelper(op->get())) {
           diagnosticEmitter.emitNamedSendingNeverSendableToSendingParam(
               loc, *varName);
@@ -2020,7 +2205,6 @@ bool SentNeverSendableDiagnosticInferrer::run() {
     }
 
     // See if we can infer a name from the value.
-    SmallString<64> resultingName;
     if (auto name = inferNameHelper(op->get())) {
       diagnosticEmitter.emitNamedIsolation(loc, *name, *isolation);
       return true;
@@ -2068,7 +2252,6 @@ bool SentNeverSendableDiagnosticInferrer::run() {
                           }) &&
              "All result info must be the same... if that changes... update "
              "this code!");
-      SmallString<64> resultingName;
       if (auto name = inferNameHelper(op->get())) {
         diagnosticEmitter.emitNamedSendingReturn(loc, *name);
         return true;
@@ -2109,12 +2292,16 @@ bool SentNeverSendableDiagnosticInferrer::run() {
 }
 
 //===----------------------------------------------------------------------===//
-//              MARK: InOutSendingNotDisconnected Error Emitter
+//               MARK: InOutSendingReturnedError Error Emitter
 //===----------------------------------------------------------------------===//
 
 namespace {
 
-class InOutSendingNotDisconnectedDiagnosticEmitter {
+class InOutSendingReturnedDiagnosticEmitter {
+  /// A region analysis function info that we use if we need to determine which
+  /// incoming block edge had an error upon it.
+  RegionAnalysisFunctionInfo *raFuncInfo;
+
   /// The function exiting inst where the 'inout sending' parameter was actor
   /// isolated.
   TermInst *functionExitingInst;
@@ -2122,21 +2309,35 @@ class InOutSendingNotDisconnectedDiagnosticEmitter {
   /// The 'inout sending' param that we are emitting an error for.
   SILValue inoutSendingParam;
 
-  /// The dynamic actor isolated region info of our 'inout sending' value's
-  /// region at the terminator inst.
-  SILDynamicMergedIsolationInfo actorIsolatedRegionInfo;
+  /// The element number of the 'inout sending' param.
+  Element inoutSendingParamElement;
+
+  /// If we did not return the 'inout sending' param directly but instead
+  /// returned something else in the same region. This is that value.
+  ///
+  /// If we actually returned the inout sending parameter this is SILValue().
+  SILValue returnedValue;
+
+  /// If we had a failure due to returning a value that is actor isolated due to
+  /// it being in the same region as an out parameter. THis is the actor
+  /// isolation.
+  SILDynamicMergedIsolationInfo isolationInfo;
 
   bool emittedErrorDiagnostic = false;
 
 public:
-  InOutSendingNotDisconnectedDiagnosticEmitter(
-      TermInst *functionExitingInst, SILValue inoutSendingParam,
-      SILDynamicMergedIsolationInfo actorIsolatedRegionInfo)
-      : functionExitingInst(functionExitingInst),
+  class LastValueEnum;
+
+  InOutSendingReturnedDiagnosticEmitter(
+      RegionAnalysisFunctionInfo *raFuncInfo, TermInst *functionExitingInst,
+      SILValue inoutSendingParam, Element inoutSendingParamElement,
+      SILValue erroringValue, SILDynamicMergedIsolationInfo isolationInfo)
+      : raFuncInfo(raFuncInfo), functionExitingInst(functionExitingInst),
         inoutSendingParam(inoutSendingParam),
-        actorIsolatedRegionInfo(actorIsolatedRegionInfo) {}
+        inoutSendingParamElement(inoutSendingParamElement),
+        returnedValue(erroringValue), isolationInfo(isolationInfo) {}
 
-  ~InOutSendingNotDisconnectedDiagnosticEmitter() {
+  ~InOutSendingReturnedDiagnosticEmitter() {
     // If we were supposed to emit a diagnostic and didn't emit an unknown
     // pattern error.
     if (!emittedErrorDiagnostic)
@@ -2163,13 +2364,642 @@ class InOutSendingNotDisconnectedDiagnosticEmitter {
 
   void emit();
 
-  ASTContext &getASTContext() const {
-    return functionExitingInst->getFunction()->getASTContext();
+  /// Called if we return the actual inout sending value.
+  void emitReturnInOutSendingError(SILDynamicMergedIsolationInfo isolationInfo,
+                                   SILLocation loc) {
+    // We should always be able to find a name for an inout sending param. If we
+    // do not, emit an unknown pattern error.
+    auto inoutSendingParamName = inferNameHelper(inoutSendingParam);
+    if (!inoutSendingParamName) {
+      return emitUnknownPatternError();
+    }
+
+    diagnoseError(
+        loc, diag::regionbasedisolation_inout_sending_cannot_be_returned_param,
+        *inoutSendingParamName)
+        .limitBehaviorIf(getBehaviorLimit());
+    if (isolationInfo->isActorIsolated()) {
+      diagnoseNote(
+          loc,
+          diag::
+              regionbasedisolation_inout_sending_cannot_be_returned_note_actor_param,
+          *inoutSendingParamName,
+          isolationInfo->printForDiagnostics(getFunction()));
+      return;
+    }
+    diagnoseNote(
+        loc,
+        diag::regionbasedisolation_inout_sending_cannot_be_returned_note_param,
+        *inoutSendingParamName);
   }
 
-  template <typename... T, typename... U>
-  InFlightDiagnostic diagnoseError(SourceLoc loc, Diag<T...> diag,
-                                   U &&...args) {
+  void emitValueError(SILValue value,
+                      SILDynamicMergedIsolationInfo isolationInfo,
+                      SILLocation loc) {
+    // We should always be able to find a name for an inout sending param. If we
+    // do not, emit an unknown pattern error.
+    auto inoutSendingParamName = inferNameHelper(inoutSendingParam);
+    if (!inoutSendingParamName) {
+      return emitUnknownPatternError();
+    }
+
+    std::optional<Identifier> erroringEltName = inferNameHelper(value);
+    if (!erroringEltName) {
+      return emitUnknownPatternError();
+    }
+
+    diagnoseError(
+        loc, diag::regionbasedisolation_inout_sending_cannot_be_returned_value,
+        *erroringEltName)
+        .limitBehaviorIf(getBehaviorLimit());
+    if (isolationInfo->isActorIsolated()) {
+      diagnoseNote(
+          loc,
+          diag::
+              regionbasedisolation_inout_sending_cannot_be_returned_note_actor_value,
+          *erroringEltName, *inoutSendingParamName,
+          isolationInfo->printForDiagnostics(getFunction()));
+      return;
+    }
+    diagnoseNote(
+        loc,
+        diag::regionbasedisolation_inout_sending_cannot_be_returned_note_value,
+        *erroringEltName, *inoutSendingParamName);
+  }
+
+  /// Print \p value in a standard way. Allow for loc to override the specific
+  /// location used to emit the diagnostic fi non-standard.
+  void emitLastValueEnum(const LastValueEnum &value,
+                         SILDynamicMergedIsolationInfo isolationInfo,
+                         SILLocation loc = SILLocation::invalid());
+
+  /// Emit an error for use when we are processing the incoming value of a phi
+  /// argument or of the dynamic value of an indirect out parameter.
+  bool emitOutParamIncomingValueError(const LastValueEnum &value);
+
+  void emitDeclRefError(SILDeclRef declRef,
+                        SILDynamicMergedIsolationInfo isolationInfo,
+                        SILLocation loc) {
+    // We should always be able to find a name for an inout sending param. If we
+    // do not, emit an unknown pattern error.
+    auto inoutSendingParamName = inferNameHelper(inoutSendingParam);
+    if (!inoutSendingParamName) {
+      return emitUnknownPatternError();
+    }
+
+    diagnoseError(
+        loc,
+        diag::
+            regionbasedisolation_inout_sending_cannot_be_returned_value_result,
+        declRef.getAbstractFunctionDecl())
+        .limitBehaviorIf(getBehaviorLimit());
+
+    if (isolationInfo->isActorIsolated()) {
+      diagnoseNote(
+          loc,
+          diag::
+              regionbasedisolation_inout_sending_cannot_be_returned_note_actor_return_value,
+          declRef.getAbstractFunctionDecl(), *inoutSendingParamName,
+          isolationInfo.printForDiagnostics(getFunction()));
+      return;
+    }
+    diagnoseNote(
+        loc,
+        diag::
+            regionbasedisolation_inout_sending_cannot_be_returned_note_return_value,
+        declRef.getAbstractFunctionDecl(), *inoutSendingParamName);
+  }
+
+  ASTContext &getASTContext() const {
+    return functionExitingInst->getFunction()->getASTContext();
+  }
+
+  template <typename... T, typename... U>
+  InFlightDiagnostic diagnoseError(SourceLoc loc, Diag<T...> diag,
+                                   U &&...args) {
+    emittedErrorDiagnostic = true;
+    return std::move(getASTContext()
+                         .Diags.diagnose(loc, diag, std::forward<U>(args)...)
+                         .warnUntilSwiftVersion(6));
+  }
+
+  template <typename... T, typename... U>
+  InFlightDiagnostic diagnoseError(SILLocation loc, Diag<T...> diag,
+                                   U &&...args) {
+    return diagnoseError(loc.getSourceLoc(), diag, std::forward<U>(args)...);
+  }
+
+  template <typename... T, typename... U>
+  InFlightDiagnostic diagnoseError(SILInstruction *inst, Diag<T...> diag,
+                                   U &&...args) {
+    return diagnoseError(inst->getLoc(), diag, std::forward<U>(args)...);
+  }
+
+  template <typename... T, typename... U>
+  InFlightDiagnostic diagnoseNote(SourceLoc loc, Diag<T...> diag, U &&...args) {
+    return getASTContext().Diags.diagnose(loc, diag, std::forward<U>(args)...);
+  }
+
+  template <typename... T, typename... U>
+  InFlightDiagnostic diagnoseNote(SILLocation loc, Diag<T...> diag,
+                                  U &&...args) {
+    return diagnoseNote(loc.getSourceLoc(), diag, std::forward<U>(args)...);
+  }
+
+  template <typename... T, typename... U>
+  InFlightDiagnostic diagnoseNote(SILInstruction *inst, Diag<T...> diag,
+                                  U &&...args) {
+    return diagnoseNote(inst->getLoc(), diag, std::forward<U>(args)...);
+  }
+};
+
+} // namespace
+
+static SILValue lookThroughAccess(SILValue value) {
+  while (true) {
+    // We look through access, copies, and loads.
+    if (auto *bai = dyn_cast<BeginAccessInst>(value)) {
+      value = bai->getOperand();
+      continue;
+    }
+
+    if (auto *cvi = dyn_cast<CopyValueInst>(value)) {
+      value = cvi->getOperand();
+      continue;
+    }
+
+    if (auto *bbi = dyn_cast<BeginBorrowInst>(value);
+        bbi && !bbi->isFromVarDecl()) {
+      value = bbi->getOperand();
+      continue;
+    }
+
+    if (auto *mvi = dyn_cast<MoveValueInst>(value);
+        mvi && !mvi->isFromVarDecl()) {
+      value = mvi->getOperand();
+      continue;
+    }
+
+    if (auto *li = dyn_cast<LoadInst>(value)) {
+      value = li->getOperand();
+      continue;
+    }
+
+    if (auto *lbi = dyn_cast<LoadBorrowInst>(value)) {
+      value = lbi->getOperand();
+      continue;
+    }
+
+    return value;
+  }
+}
+
+class InOutSendingReturnedDiagnosticEmitter::LastValueEnum {
+public:
+  enum Kind {
+    None,
+    ApplySite,
+    CopyAddr,
+    Store,
+    Value,
+    ReturnTerm,
+  };
+
+private:
+  Kind kind;
+  std::variant<FullApplySite, SILValue, CopyAddrInst *, StoreInst *, Operand *>
+      value;
+
+  LastValueEnum() : kind(Kind::None), value() {}
+  LastValueEnum(FullApplySite inst) : kind(Kind::ApplySite), value(inst) {}
+  LastValueEnum(SILValue value) : kind(Kind::Value), value(value) {}
+  LastValueEnum(CopyAddrInst *inst) : kind(Kind::CopyAddr), value(inst) {}
+  LastValueEnum(StoreInst *inst) : kind(Kind::Store), value(inst) {}
+  LastValueEnum(Operand *branchUse) : kind(Kind::ReturnTerm), value(branchUse) {
+    assert(isa<TermInst>(branchUse->getUser()));
+    assert(branchUse->getUser()->getLoc().getKind() == SILLocation::ReturnKind);
+  }
+
+public:
+  static LastValueEnum get(SILValue value);
+  static LastValueEnum get(SILInstruction *inst);
+  static LastValueEnum get(Operand *use);
+  static bool isSupported(Operand *use);
+
+  operator bool() const { return getKind() != Kind::None; }
+
+  Kind getKind() const { return kind; }
+  bool isApplySite() const { return getKind() == Kind::ApplySite; }
+  bool isValue() const { return getKind() == Kind::Value; }
+  bool isStore() const { return getKind() == Kind::Store; }
+  bool isCopyAddr() const { return getKind() == Kind::CopyAddr; }
+
+  /// Is this a terminator instruction that is an incoming value to an epilogue
+  /// block and thus forms part of the return from a function.
+  bool isReturnTerm() const { return getKind() == Kind::ReturnTerm; }
+
+  FullApplySite getFullApplySite() const {
+    return std::get<FullApplySite>(value);
+  }
+  SILDeclRef getDeclRef() const {
+    return getFullApplySite().getCalleeFunction()->getDeclRef();
+  }
+  SILValue getValue() const {
+    switch (getKind()) {
+    case None:
+    case ApplySite:
+      return SILValue();
+    case CopyAddr:
+      return getCopyAddr()->getAllOperands()[CopyLikeInstruction::Src].get();
+    case Store:
+      return getStore()->getAllOperands()[CopyLikeInstruction::Src].get();
+    case Value:
+      return std::get<SILValue>(value);
+    case ReturnTerm:
+      return std::get<Operand *>(value)->get();
+    }
+  }
+  CopyAddrInst *getCopyAddr() const { return std::get<CopyAddrInst *>(value); }
+  StoreInst *getStore() const { return std::get<StoreInst *>(value); }
+  Operand *getReturnTerm() const { return std::get<Operand *>(value); }
+
+  SILBasicBlock *getParentBlock() const {
+    switch (getKind()) {
+    case None:
+      return nullptr;
+    case ApplySite:
+      return getFullApplySite()->getParent();
+    case Value:
+      return getValue()->getParentBlock();
+    case CopyAddr:
+      return getCopyAddr()->getParentBlock();
+    case Store:
+      return getStore()->getParentBlock();
+    case ReturnTerm:
+      return getReturnTerm()->getParentBlock();
+    }
+  }
+
+  SILInstruction *getDefiningInsertionPoint() const {
+    switch (getKind()) {
+    case None:
+      return nullptr;
+    case ApplySite:
+      return *getFullApplySite();
+    case Value:
+      return getValue()->getDefiningInsertionPoint();
+    case CopyAddr:
+      return getCopyAddr();
+    case Store:
+      return getStore();
+    case ReturnTerm:
+      return getReturnTerm()->getUser();
+    }
+  }
+
+  SILLocation getLoc() const {
+    switch (getKind()) {
+    case None:
+      return SILLocation::invalid();
+    case ApplySite:
+    case Value:
+    case CopyAddr:
+    case Store:
+    case ReturnTerm:
+      return getDefiningInsertionPoint()->getLoc();
+    }
+  }
+
+  bool operator==(SILValue otherValue) const {
+    switch (getKind()) {
+    case None:
+    case ApplySite:
+      return false;
+    case CopyAddr:
+    case Store:
+    case Value:
+    case ReturnTerm:
+      return lookThroughAccess(getValue()) == lookThroughAccess(otherValue);
+    }
+  }
+
+  static bool
+  findLastValuesForOutParam(SILFunctionArgument *fArg,
+                            SmallVectorImpl<LastValueEnum> &lastValues);
+
+  void print(llvm::raw_ostream &os) const {
+    switch (getKind()) {
+    case None:
+      os << "none\n";
+      return;
+    case ApplySite:
+      os << "apply site: " << *getFullApplySite();
+      return;
+    case CopyAddr:
+      os << "copy_addr: " << *getCopyAddr();
+      return;
+    case Store:
+      os << "store: " << *getStore();
+      return;
+    case Value:
+      os << "value: " << *getValue();
+      break;
+    case ReturnTerm:
+      os << "return term: " << *getReturnTerm()->getUser();
+    }
+  }
+
+  SWIFT_DEBUG_DUMP { print(llvm::dbgs()); }
+};
+
+InOutSendingReturnedDiagnosticEmitter::LastValueEnum
+InOutSendingReturnedDiagnosticEmitter::LastValueEnum::get(
+    SILInstruction *user) {
+  if (auto *cai = dyn_cast<CopyAddrInst>(user)) {
+    return {cai};
+  }
+
+  if (auto *si = dyn_cast<StoreInst>(user)) {
+    return {si};
+  }
+
+  if (auto fas = FullApplySite::isa(user)) {
+    return {fas};
+  }
+
+  return {};
+}
+
+InOutSendingReturnedDiagnosticEmitter::LastValueEnum
+InOutSendingReturnedDiagnosticEmitter::LastValueEnum::get(Operand *use) {
+  if (auto value = get(use->getUser()))
+    return value;
+
+  if (auto *ti = dyn_cast<TermInst>(use->getUser())) {
+    if (ti->getLoc().getKind() == SILLocation::ReturnKind) {
+      return {use};
+    }
+  }
+
+  return {};
+}
+
+bool InOutSendingReturnedDiagnosticEmitter::LastValueEnum::isSupported(
+    Operand *use) {
+  if (auto fas = FullApplySite::isa(use->getUser())) {
+    if (fas.isIndirectResultOperand(*use)) {
+      auto *fn = fas.getCalleeFunction();
+      return fn && fn->getDeclRef();
+    }
+  }
+
+  if (auto *ti = dyn_cast<TermInst>(use->getUser())) {
+    if (ti->getLoc().getKind() == SILLocation::ReturnKind) {
+      return true;
+    }
+  }
+
+  return isa<CopyAddrInst, StoreInst>(use->getUser());
+}
+
+InOutSendingReturnedDiagnosticEmitter::LastValueEnum
+InOutSendingReturnedDiagnosticEmitter::LastValueEnum::get(SILValue value) {
+  if (auto *inst = value->getDefiningInstruction()) {
+    if (auto e = get(inst))
+      return e;
+  }
+
+  return {value};
+}
+
+void InOutSendingReturnedDiagnosticEmitter::emitLastValueEnum(
+    const LastValueEnum &value, SILDynamicMergedIsolationInfo isolationInfo,
+    SILLocation loc) {
+  switch (value.getKind()) {
+  case LastValueEnum::None:
+    llvm::report_fatal_error("Found .none enum elt");
+  case LastValueEnum::ApplySite:
+    emitDeclRefError(value.getDeclRef(), isolationInfo,
+                     loc ? loc : value.getLoc());
+    return;
+  case LastValueEnum::Store:
+  case LastValueEnum::CopyAddr:
+    emitValueError(value.getValue(), isolationInfo, loc ? loc : value.getLoc());
+    return;
+  case LastValueEnum::Value:
+    emitValueError(value.getValue(), isolationInfo,
+                   loc ? loc : functionExitingInst->getLoc());
+    return;
+  case LastValueEnum::ReturnTerm:
+    emitValueError(value.getValue(), isolationInfo, loc ? loc : value.getLoc());
+    return;
+  }
+  llvm::report_fatal_error("Should never hit this");
+}
+
+bool InOutSendingReturnedDiagnosticEmitter::emitOutParamIncomingValueError(
+    const LastValueEnum &finalValue) {
+  auto *block = finalValue.getParentBlock();
+  auto state = raFuncInfo->getBlockState(block);
+  assert(state.isNonNull());
+
+  // Grab the exit partition of the block. We make a copy here on purpose
+  // since it /is/ possible for DiagnosticEvaluator to modify
+  auto workingExitPartition = state.get()->getExitPartition();
+
+  // See if given the exit partition of the block if we would emit an error
+  // when we execute an InOutSendingAtFunctionExit partition op.
+  SmallFrozenMultiMap<Operand *, RequireInst, 8> sendingOpToRequireInstMultiMap;
+  SmallVector<PartitionOpError, 2> errors;
+  DiagnosticEvaluator evaluator(workingExitPartition, raFuncInfo,
+                                sendingOpToRequireInstMultiMap, errors,
+                                raFuncInfo->getSendingOperandToStateMap());
+  PartitionOp op = PartitionOp::InOutSendingAtFunctionExit(
+      inoutSendingParamElement, finalValue.getDefiningInsertionPoint());
+  evaluator.apply(op);
+
+  // Check if we got an error. If we did not, then this is not one of the
+  // guilty code paths. Continue.
+  if (errors.empty()) {
+    return false;
+  }
+
+  // Loop through the errors to find our InOutReturnedError. We emit one error
+  // per return... but we emit for multiple returns separate diagnostics.
+  while (!errors.empty()) {
+    auto err = errors.pop_back_val();
+    if (err.getKind() != PartitionOpError::InOutSendingReturned)
+      continue;
+    auto castError = std::move(err).getInOutSendingReturnedError();
+    if (castError.inoutSendingElement != inoutSendingParamElement)
+      continue;
+    // Ok, we found an error. Lets emit it and return early.
+    if (finalValue == inoutSendingParam) {
+      emitReturnInOutSendingError(isolationInfo, finalValue.getLoc());
+      return true;
+    }
+
+    // Force us to use the location of the finalValue. We do not want to use the
+    // function exiting inst.
+    emitLastValueEnum(finalValue, isolationInfo, finalValue.getLoc());
+    return true;
+  }
+
+  return false;
+}
+
+void InOutSendingReturnedDiagnosticEmitter::emit() {
+  // Check if we had a separate erroring value that is our returned value. If we
+  // do not then we just returned the 'inout sending' parameter. Emit a special
+  // message and return.
+  if (inoutSendingParam == returnedValue) {
+    return emitReturnInOutSendingError(isolationInfo,
+                                       functionExitingInst->getLoc());
+  }
+
+  // Before we do anything, see if we have a phi argument that is an epilogue
+  // phi. In such a case, we want to process the incoming values.
+  if (auto *phi = dyn_cast<SILPhiArgument>(returnedValue)) {
+    bool handledValue = false;
+    phi->visitIncomingPhiOperands([&](Operand *op) {
+      if (op->getUser()->getLoc().getKind() != SILLocation::ReturnKind)
+        return true;
+      handledValue |=
+          emitOutParamIncomingValueError(LastValueEnum::get(op->get()));
+      return true;
+    });
+    if (handledValue)
+      return;
+  }
+
+  // Check if we have an indirect out parameter as our erroring returned value.
+  auto *fArg = dyn_cast<SILFunctionArgument>(returnedValue);
+  if (!fArg || !fArg->isIndirectResult()) {
+    // If we do not have one... emit a normal error.
+    return emitLastValueEnum(LastValueEnum::get(returnedValue), isolationInfo);
+  }
+
+  SmallVector<LastValueEnum, 8> finalValues;
+  if (!LastValueEnum::findLastValuesForOutParam(fArg, finalValues))
+    return emitLastValueEnum(LastValueEnum::get(returnedValue), isolationInfo);
+
+  // If we have a single value, then we have found our value.
+  if (finalValues.size() == 1) {
+    if (finalValues[0] == inoutSendingParam) {
+      return emitReturnInOutSendingError(isolationInfo,
+                                         finalValues[0].getLoc());
+    }
+    emitLastValueEnum(finalValues[0], isolationInfo);
+    return;
+  }
+
+  // If we have multiple finalValues, then that means that we had multiple
+  // return values. In such a case, we must have a single epilog block
+  // that our finalValues jointly dominate. That means that we need to
+  // determine which block the error actually occured along and emit an
+  // error for the value in that block. We know we are going to emit an
+  // error, so we can spend more time finding the better diagnostic since
+  // we are going to fail.
+  for (auto finalValue : finalValues) {
+    emitOutParamIncomingValueError(finalValue);
+  }
+}
+
+bool InOutSendingReturnedDiagnosticEmitter::LastValueEnum::
+    findLastValuesForOutParam(SILFunctionArgument *fArg,
+                              SmallVectorImpl<LastValueEnum> &lastValues) {
+  assert(fArg->isIndirectResult());
+  SmallVector<SILBasicBlock *, 8> visitedBlocks;
+  SSAPrunedLiveness prunedLiveRange(fArg->getFunction(), &visitedBlocks);
+
+  // Look for copy_addr and store uses into fArg. They should all be complete
+  // stores.
+  prunedLiveRange.initializeDef(fArg);
+  for (auto *use : fArg->getUses()) {
+    if (LastValueEnum::isSupported(use)) {
+      prunedLiveRange.updateForUse(use->getUser(), false /*lifetime ending*/);
+      continue;
+    }
+    return false;
+  }
+
+  PrunedLivenessBoundary boundary;
+  prunedLiveRange.computeBoundary(boundary);
+
+  for (auto *user : boundary.lastUsers) {
+    if (auto e = LastValueEnum::get(user)) {
+      lastValues.emplace_back(e);
+      continue;
+    }
+
+    llvm::report_fatal_error("Out of sync with earlier check");
+  }
+
+  return true;
+}
+
+//===----------------------------------------------------------------------===//
+//              MARK: InOutSendingNotDisconnected Error Emitter
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+class InOutSendingNotDisconnectedDiagnosticEmitter {
+  /// The function exiting inst where the 'inout sending' parameter was actor
+  /// isolated.
+  TermInst *functionExitingInst;
+
+  /// The 'inout sending' param that we are emitting an error for.
+  SILValue inoutSendingParam;
+
+  /// The dynamic actor isolated region info of our 'inout sending' value's
+  /// region at the terminator inst.
+  SILDynamicMergedIsolationInfo actorIsolatedRegionInfo;
+
+  bool emittedErrorDiagnostic = false;
+
+public:
+  InOutSendingNotDisconnectedDiagnosticEmitter(
+      TermInst *functionExitingInst, SILValue inoutSendingParam,
+      SILDynamicMergedIsolationInfo actorIsolatedRegionInfo)
+      : functionExitingInst(functionExitingInst),
+        inoutSendingParam(inoutSendingParam),
+        actorIsolatedRegionInfo(actorIsolatedRegionInfo) {}
+
+  ~InOutSendingNotDisconnectedDiagnosticEmitter() {
+    // If we were supposed to emit a diagnostic and didn't emit an unknown
+    // pattern error.
+    if (!emittedErrorDiagnostic)
+      emitUnknownPatternError();
+  }
+
+  SILFunction *getFunction() const { return inoutSendingParam->getFunction(); }
+
+  std::optional<DiagnosticBehavior> getBehaviorLimit() const {
+    return inoutSendingParam->getType().getConcurrencyDiagnosticBehavior(
+        getFunction());
+  }
+
+  void emitUnknownPatternError() {
+    if (shouldAbortOnUnknownPatternMatchError()) {
+      llvm::report_fatal_error(
+          "RegionIsolation: Aborting on unknown pattern match error");
+    }
+
+    diagnoseError(functionExitingInst,
+                  diag::regionbasedisolation_unknown_pattern)
+        .limitBehaviorIf(getBehaviorLimit());
+  }
+
+  void emit();
+
+  ASTContext &getASTContext() const {
+    return functionExitingInst->getFunction()->getASTContext();
+  }
+
+  template <typename... T, typename... U>
+  InFlightDiagnostic diagnoseError(SourceLoc loc, Diag<T...> diag,
+                                   U &&...args) {
     emittedErrorDiagnostic = true;
     return std::move(getASTContext()
                          .Diags.diagnose(loc, diag, std::forward<U>(args)...)
@@ -2217,12 +3047,8 @@ void InOutSendingNotDisconnectedDiagnosticEmitter::emit() {
   }
 
   // Then emit the note with greater context.
-  SmallString<64> descriptiveKindStr;
-  {
-    llvm::raw_svector_ostream os(descriptiveKindStr);
-    actorIsolatedRegionInfo.printForDiagnostics(os);
-    os << ' ';
-  }
+  auto descriptiveKindStr =
+      actorIsolatedRegionInfo.printForDiagnostics(getFunction());
 
   diagnoseError(
       functionExitingInst,
@@ -2377,11 +3203,8 @@ static SILValue findOutParameter(SILValue v) {
 
 void AssignIsolatedIntoSendingResultDiagnosticEmitter::emit() {
   // Then emit the note with greater context.
-  SmallString<64> descriptiveKindStr;
-  {
-    llvm::raw_svector_ostream os(descriptiveKindStr);
-    isolatedValueIsolationRegionInfo.printForDiagnostics(os);
-  }
+  auto descriptiveKindStr =
+      isolatedValueIsolationRegionInfo.printForDiagnostics(getFunction());
 
   // Grab the var name if we can find it.
   if (auto varName = VariableNameInferrer::inferName(srcOperand->get())) {
@@ -2501,10 +3324,14 @@ struct NonSendableIsolationCrossingResultDiagnosticEmitter {
   SILValue representative;
 
   NonSendableIsolationCrossingResultDiagnosticEmitter(
-      RegionAnalysisValueMap &valueMap, Error error)
-      : valueMap(valueMap), error(error),
+      RegionAnalysisValueMap &valueMap, Error &&error)
+      : valueMap(valueMap), error(std::move(error)),
         representative(valueMap.getRepresentative(error.returnValueElement)) {}
 
+  SILFunction *getFunction() const {
+    return error.op->getSourceInst()->getFunction();
+  }
+
   void emit();
 
   ASTContext &getASTContext() const {
@@ -2621,17 +3448,22 @@ void NonSendableIsolationCrossingResultDiagnosticEmitter::emit() {
   if (!isolationCrossing)
     return emitUnknownPatternError();
 
+  auto calleeIsolationStr = SILIsolationInfo::printActorIsolationForDiagnostics(
+      getFunction(), isolationCrossing->getCalleeIsolation());
+  auto callerIsolationStr = SILIsolationInfo::printActorIsolationForDiagnostics(
+      getFunction(), isolationCrossing->getCallerIsolation());
+
   auto type = getType();
   if (getCalledDecl()) {
-    diagnoseError(error.op->getSourceInst(), diag::rbi_isolation_crossing_result,
-                  type, isolationCrossing->getCalleeIsolation(), getCalledDecl(),
-                  isolationCrossing->getCallerIsolation())
-      .limitBehaviorIf(getBehaviorLimit());
+    diagnoseError(error.op->getSourceInst(),
+                  diag::rbi_isolation_crossing_result, type, calleeIsolationStr,
+                  getCalledDecl(), callerIsolationStr)
+        .limitBehaviorIf(getBehaviorLimit());
   } else {
-    diagnoseError(error.op->getSourceInst(), diag::rbi_isolation_crossing_result_no_decl,
-                  type, isolationCrossing->getCalleeIsolation(),
-                  isolationCrossing->getCallerIsolation())
-      .limitBehaviorIf(getBehaviorLimit());
+    diagnoseError(error.op->getSourceInst(),
+                  diag::rbi_isolation_crossing_result_no_decl, type,
+                  calleeIsolationStr, callerIsolationStr)
+        .limitBehaviorIf(getBehaviorLimit());
   }
   if (type->is<FunctionType>()) {
     diagnoseNote(error.op->getSourceInst(),
@@ -2669,191 +3501,6 @@ void NonSendableIsolationCrossingResultDiagnosticEmitter::emit() {
   }
 }
 
-//===----------------------------------------------------------------------===//
-//                         MARK: Diagnostic Evaluator
-//===----------------------------------------------------------------------===//
-
-namespace {
-
-struct DiagnosticEvaluator final
-    : PartitionOpEvaluatorBaseImpl<DiagnosticEvaluator> {
-  RegionAnalysisFunctionInfo *info;
-  SmallFrozenMultiMap<Operand *, RequireInst, 8>
-      &sendingOpToRequireInstMultiMap;
-
-  /// An error that we know how to emit verbatim without needing to preprocess.
-  ///
-  /// A contrasting case here is the use after send error where we need to pair
-  /// sending operands to require insts.
-  SmallVectorImpl<PartitionOpError> &foundVerbatimErrors;
-
-  DiagnosticEvaluator(Partition &workingPartition,
-                      RegionAnalysisFunctionInfo *info,
-                      SmallFrozenMultiMap<Operand *, RequireInst, 8>
-                          &sendingOpToRequireInstMultiMap,
-                      SmallVectorImpl<PartitionOpError> &foundVerbatimErrors,
-                      SendingOperandToStateMap &operandToStateMap)
-      : PartitionOpEvaluatorBaseImpl(
-            workingPartition, info->getOperandSetFactory(), operandToStateMap),
-        info(info),
-        sendingOpToRequireInstMultiMap(sendingOpToRequireInstMultiMap),
-        foundVerbatimErrors(foundVerbatimErrors) {}
-
-  void handleLocalUseAfterSend(LocalUseAfterSendError error) const {
-    const auto &partitionOp = *error.op;
-
-    auto &operandState = operandToStateMap.get(error.sendingOp);
-    // Ignore this if we have a gep like instruction that is returning a
-    // sendable type and sendingOp was not set with closure
-    // capture.
-    if (auto *svi =
-            dyn_cast<SingleValueInstruction>(partitionOp.getSourceInst())) {
-      if (isa<TupleElementAddrInst, StructElementAddrInst>(svi) &&
-          !SILIsolationInfo::isNonSendableType(svi->getType(),
-                                               svi->getFunction())) {
-        bool isCapture = operandState.isClosureCaptured;
-        if (!isCapture) {
-          return;
-        }
-      }
-    }
-
-    REGIONBASEDISOLATION_LOG(error.print(llvm::dbgs(), info->getValueMap()));
-    sendingOpToRequireInstMultiMap.insert(
-        error.sendingOp, RequireInst::forUseAfterSend(partitionOp.getSourceInst()));
-  }
-
-  void handleInOutSendingNotInitializedAtExitError(
-      InOutSendingNotInitializedAtExitError error) const {
-    const PartitionOp &partitionOp = *error.op;
-    Operand *sendingOp = error.sendingOp;
-
-    REGIONBASEDISOLATION_LOG(error.print(llvm::dbgs(), info->getValueMap()));
-
-    sendingOpToRequireInstMultiMap.insert(
-        sendingOp, RequireInst::forInOutReinitializationNeeded(
-                       partitionOp.getSourceInst()));
-  }
-
-  void handleUnknownCodePattern(UnknownCodePatternError error) const {
-    const PartitionOp &op = *error.op;
-
-    if (shouldAbortOnUnknownPatternMatchError()) {
-      llvm::report_fatal_error(
-          "RegionIsolation: Aborting on unknown pattern match error");
-    }
-
-    diagnoseError(op.getSourceInst(),
-                  diag::regionbasedisolation_unknown_pattern);
-  }
-
-  void handleError(PartitionOpError error) {
-    switch (error.getKind()) {
-    case PartitionOpError::LocalUseAfterSend: {
-      return handleLocalUseAfterSend(error.getLocalUseAfterSendError());
-    }
-    case PartitionOpError::InOutSendingNotDisconnectedAtExit:
-    case PartitionOpError::SentNeverSendable:
-    case PartitionOpError::AssignNeverSendableIntoSendingResult:
-    case PartitionOpError::NonSendableIsolationCrossingResult:
-      // We are going to process these later... but dump so we can see that we
-      // handled an error here. The rest of the explicit handlers will dump as
-      // appropriate if they want to emit an error here (some will squelch the
-      // error).
-      REGIONBASEDISOLATION_LOG(error.print(llvm::dbgs(), info->getValueMap()));
-      foundVerbatimErrors.emplace_back(error);
-      return;
-    case PartitionOpError::InOutSendingNotInitializedAtExit: {
-      return handleInOutSendingNotInitializedAtExitError(
-          error.getInOutSendingNotInitializedAtExitError());
-    }
-    case PartitionOpError::UnknownCodePattern: {
-      return handleUnknownCodePattern(error.getUnknownCodePatternError());
-    }
-    }
-    llvm_unreachable("Covered switch isn't covered?!");
-  }
-
-  bool isActorDerived(Element element) const {
-    return info->getValueMap().getIsolationRegion(element).isActorIsolated();
-  }
-
-  bool isTaskIsolatedDerived(Element element) const {
-    return info->getValueMap().getIsolationRegion(element).isTaskIsolated();
-  }
-
-  SILIsolationInfo::Kind hasSpecialDerivation(Element element) const {
-    return info->getValueMap().getIsolationRegion(element).getKind();
-  }
-
-  SILIsolationInfo getIsolationRegionInfo(Element element) const {
-    return info->getValueMap().getIsolationRegion(element);
-  }
-
-  std::optional<Element> getElement(SILValue value) const {
-    return info->getValueMap().getTrackableValue(value).getID();
-  }
-
-  SILValue getRepresentative(SILValue value) const {
-    return info->getValueMap()
-        .getTrackableValue(value)
-        .getRepresentative()
-        .maybeGetValue();
-  }
-
-  RepresentativeValue getRepresentativeValue(Element element) const {
-    return info->getValueMap().getRepresentativeValue(element);
-  }
-
-  bool isClosureCaptured(Element element, Operand *op) const {
-    auto value = info->getValueMap().maybeGetRepresentative(element);
-    if (!value)
-      return false;
-    return info->isClosureCaptured(value, op);
-  }
-};
-
-} // namespace
-
-void SendNonSendableImpl::runDiagnosticEvaluator() {
-  // Then for each block...
-  REGIONBASEDISOLATION_LOG(llvm::dbgs() << "Walking blocks for diagnostics.\n");
-  for (auto [block, blockState] : info->getRange()) {
-    REGIONBASEDISOLATION_LOG(llvm::dbgs()
-                             << "|--> Block bb" << block.getDebugID() << "\n");
-
-    if (!blockState.getLiveness()) {
-      REGIONBASEDISOLATION_LOG(llvm::dbgs() << "Dead block... skipping!\n");
-      continue;
-    }
-
-    REGIONBASEDISOLATION_LOG(
-        llvm::dbgs() << "Entry Partition: ";
-        blockState.getEntryPartition().print(llvm::dbgs()));
-
-    // Grab its entry partition and setup an evaluator for the partition that
-    // has callbacks that emit diagnsotics...
-    Partition workingPartition = blockState.getEntryPartition();
-    DiagnosticEvaluator eval(
-        workingPartition, info, sendingOpToRequireInstMultiMap,
-        foundVerbatimErrors, info->getSendingOperandToStateMap());
-
-    // And then evaluate all of our partition ops on the entry partition.
-    for (auto &partitionOp : blockState.getPartitionOps()) {
-      eval.apply(partitionOp);
-    }
-
-    REGIONBASEDISOLATION_LOG(llvm::dbgs() << "Exit Partition: ";
-                             workingPartition.print(llvm::dbgs()));
-  }
-
-  REGIONBASEDISOLATION_LOG(llvm::dbgs()
-                           << "Finished walking blocks for diagnostics.\n");
-
-  // Now that we have found all of our sendingInsts/Requires emit errors.
-  sendingOpToRequireInstMultiMap.setFrozen();
-}
-
 //===----------------------------------------------------------------------===//
 //                         MARK: Top Level Entrypoint
 //===----------------------------------------------------------------------===//
@@ -2866,7 +3513,8 @@ void SendNonSendableImpl::emitVerbatimErrors() {
     case PartitionOpError::InOutSendingNotInitializedAtExit:
       llvm_unreachable("Handled elsewhere");
     case PartitionOpError::AssignNeverSendableIntoSendingResult: {
-      auto error = erasedError.getAssignNeverSendableIntoSendingResultError();
+      auto error =
+          std::move(erasedError).getAssignNeverSendableIntoSendingResultError();
       REGIONBASEDISOLATION_LOG(error.print(llvm::dbgs(), info->getValueMap()));
       AssignIsolatedIntoSendingResultDiagnosticEmitter emitter(
           error.op->getSourceOp(), error.destValue, error.srcValue,
@@ -2875,7 +3523,8 @@ void SendNonSendableImpl::emitVerbatimErrors() {
       continue;
     }
     case PartitionOpError::InOutSendingNotDisconnectedAtExit: {
-      auto error = erasedError.getInOutSendingNotDisconnectedAtExitError();
+      auto error =
+          std::move(erasedError).getInOutSendingNotDisconnectedAtExitError();
       auto inoutSendingVal =
           info->getValueMap().getRepresentative(error.inoutSendingElement);
       auto isolationRegionInfo = error.isolationInfo;
@@ -2888,19 +3537,35 @@ void SendNonSendableImpl::emitVerbatimErrors() {
       emitter.emit();
       continue;
     }
+    case PartitionOpError::InOutSendingReturned: {
+      auto error = std::move(erasedError).getInOutSendingReturnedError();
+      auto inoutSendingVal =
+          info->getValueMap().getRepresentative(error.inoutSendingElement);
+      auto returnedValue =
+          info->getValueMap().getRepresentative(error.returnedValue);
+
+      REGIONBASEDISOLATION_LOG(error.print(llvm::dbgs(), info->getValueMap()));
+
+      InOutSendingReturnedDiagnosticEmitter emitter(
+          info, cast<TermInst>(error.op->getSourceInst()), inoutSendingVal,
+          error.inoutSendingElement, returnedValue, error.isolationInfo);
+      emitter.emit();
+      continue;
+    }
     case PartitionOpError::SentNeverSendable: {
-      auto e = erasedError.getSentNeverSendableError();
+      auto e = std::move(erasedError).getSentNeverSendableError();
       REGIONBASEDISOLATION_LOG(e.print(llvm::dbgs(), info->getValueMap()));
       SentNeverSendableDiagnosticInferrer diagnosticInferrer(
-          info->getValueMap(), e);
+          info->getValueMap(), std::move(e));
       diagnosticInferrer.run();
       continue;
     }
     case PartitionOpError::NonSendableIsolationCrossingResult: {
-      auto e = erasedError.getNonSendableIsolationCrossingResultError();
+      auto e =
+          std::move(erasedError).getNonSendableIsolationCrossingResultError();
       REGIONBASEDISOLATION_LOG(e.print(llvm::dbgs(), info->getValueMap()));
       NonSendableIsolationCrossingResultDiagnosticEmitter diagnosticInferrer(
-          info->getValueMap(), e);
+          info->getValueMap(), std::move(e));
       diagnosticInferrer.emit();
       continue;
     }
diff --git a/lib/SILOptimizer/PassManager/PassManager.cpp b/lib/SILOptimizer/PassManager/PassManager.cpp
index f01e663412e92..09219670b4c8f 100644
--- a/lib/SILOptimizer/PassManager/PassManager.cpp
+++ b/lib/SILOptimizer/PassManager/PassManager.cpp
@@ -27,6 +27,8 @@
 #include "swift/SILOptimizer/PassManager/PrettyStackTrace.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/OptimizerStatsUtils.h"
+#include "swift/SILOptimizer/Utils/SILOptFunctionBuilder.h"
+#include "swift/SILOptimizer/Utils/SILSSAUpdater.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -575,8 +577,6 @@ void SILPassManager::dumpPassInfo(const char *Title, unsigned TransIdx,
 
 bool SILPassManager::isMandatoryFunctionPass(SILFunctionTransform *sft) {
   return isMandatory ||
-         sft->getPassKind() ==
-             PassKind::NonTransparentFunctionOwnershipModelEliminator ||
          sft->getPassKind() == PassKind::OwnershipModelEliminator;
 }
 
@@ -1427,197 +1427,152 @@ void SILPassManager::viewCallGraph() {
 //                           SwiftPassInvocation
 //===----------------------------------------------------------------------===//
 
-FixedSizeSlab *SwiftPassInvocation::allocSlab(FixedSizeSlab *afterSlab) {
-  FixedSizeSlab *slab = passManager->getModule()->allocSlab();
-  if (afterSlab) {
-    allocatedSlabs.insert(std::next(afterSlab->getIterator()), *slab);
-  } else {
-    allocatedSlabs.push_back(*slab);
-  }
-  return slab;
+void SwiftPassInvocation::startModulePassRun(SILModuleTransform *transform) {
+  ASSERT(!this->function && !this->transform && "a pass is already running");
+  this->transform = transform;
 }
 
-FixedSizeSlab *SwiftPassInvocation::freeSlab(FixedSizeSlab *slab) {
-  FixedSizeSlab *prev = nullptr;
-  assert(!allocatedSlabs.empty());
-  if (&allocatedSlabs.front() != slab)
-    prev = &*std::prev(slab->getIterator());
-
-  allocatedSlabs.remove(*slab);
-  passManager->getModule()->freeSlab(slab);
-  return prev;
+void SwiftPassInvocation::finishedModulePassRun() {
+  ASSERT(!function && transform && "not running a module pass");
+  if (changeNotifications != 0) {
+    ASSERT((changeNotifications & ~SILContext::NotificationKind::FunctionTables) == 0
+           && "a module pass must change the SIL of a function");
+    passManager->invalidateFunctionTables();
+    changeNotifications = SILContext::NotificationKind::Nothing;
+  }
+  transform = nullptr;
+  verifyEverythingIsCleared();
 }
 
-BasicBlockSet *SwiftPassInvocation::allocBlockSet() {
-  ASSERT(numBlockSetsAllocated < BlockSetCapacity &&
-         "too many BasicBlockSets allocated");
-
-  auto *storage = (BasicBlockSet *)blockSetStorage + numBlockSetsAllocated;
-  BasicBlockSet *set = new (storage) BasicBlockSet(function);
-  aliveBlockSets[numBlockSetsAllocated] = true;
-  ++numBlockSetsAllocated;
-  return set;
+void SwiftPassInvocation::startFunctionPassRun(SILFunctionTransform *transform) {
+  ASSERT(!this->function && !this->transform && "a pass is already running");
+  this->transform = transform;
+  this->function = transform->getFunction();
 }
 
-void SwiftPassInvocation::freeBlockSet(BasicBlockSet *set) {
-  int idx = set - (BasicBlockSet *)blockSetStorage;
-  assert(idx >= 0 && idx < numBlockSetsAllocated);
-  assert(aliveBlockSets[idx] && "double free of BasicBlockSet");
-  aliveBlockSets[idx] = false;
+void SwiftPassInvocation::finishedFunctionPassRun() {
+  ASSERT(function && transform && "not running a function pass");
+  ASSERT((changeNotifications & SILContext::NotificationKind::FunctionTables) == 0
+         && "a function pass must not change function tables");
+  if (changeNotifications != SILContext::NotificationKind::Nothing) {
+    passManager->invalidateAnalysis(function, (SILAnalysis::InvalidationKind)changeNotifications);
+  }
+  changeNotifications = SILContext::NotificationKind::Nothing;
 
-  while (numBlockSetsAllocated > 0 && !aliveBlockSets[numBlockSetsAllocated - 1]) {
-    auto *set = (BasicBlockSet *)blockSetStorage + numBlockSetsAllocated - 1;
-    set->~BasicBlockSet();
-    --numBlockSetsAllocated;
+  insertedPhisBySSAUpdater.clear();
+  if (ssaUpdater) {
+    delete ssaUpdater;
+    ssaUpdater = nullptr;
   }
+
+  function = nullptr;
+  transform = nullptr;
+  verifyEverythingIsCleared();
 }
 
-NodeSet *SwiftPassInvocation::allocNodeSet() {
-  ASSERT(numNodeSetsAllocated < NodeSetCapacity &&
-         "too many NodeSets allocated");
+void SwiftPassInvocation::startInstructionPassRun(SILInstruction *inst) {
+  ASSERT(inst->getFunction() == function && "running instruction pass on wrong function");
+}
 
-  auto *storage = (NodeSet *)nodeSetStorage + numNodeSetsAllocated;
-  NodeSet *set = new (storage) NodeSet(function);
-  aliveNodeSets[numNodeSetsAllocated] = true;
-  ++numNodeSetsAllocated;
-  return set;
+void SwiftPassInvocation::finishedInstructionPassRun() {
+  verifyEverythingIsCleared();
 }
 
-void SwiftPassInvocation::freeNodeSet(NodeSet *set) {
-  int idx = set - (NodeSet *)nodeSetStorage;
-  assert(idx >= 0 && idx < numNodeSetsAllocated);
-  assert(aliveNodeSets[idx] && "double free of NodeSet");
-  aliveNodeSets[idx] = false;
+void SwiftPassInvocation::verifyEverythingIsCleared() {
+  ASSERT(!needFixStackNesting && "Stack nesting not fixed");
+  SILContext::verifyEverythingIsCleared();
+}
 
-  while (numNodeSetsAllocated > 0 && !aliveNodeSets[numNodeSetsAllocated - 1]) {
-    auto *set = (NodeSet *)nodeSetStorage + numNodeSetsAllocated - 1;
-    set->~NodeSet();
-    --numNodeSetsAllocated;
+void SwiftPassInvocation::beginVerifyFunction(SILFunction *function) {
+  if (transform) {
+    ASSERT(this->function == function);
+  } else {
+    ASSERT(!this->function);
+    this->function = function;
   }
 }
 
-OperandSet *SwiftPassInvocation::allocOperandSet() {
-  ASSERT(numOperandSetsAllocated < OperandSetCapacity &&
-         "too many OperandSets allocated");
+void SwiftPassInvocation::endVerifyFunction() {
+  ASSERT(function);
+  if (!transform) {
+    verifyEverythingIsCleared();
+    function = nullptr;
+  }
+}
 
-  auto *storage = (OperandSet *)operandSetStorage + numOperandSetsAllocated;
-  OperandSet *set = new (storage) OperandSet(function);
-  aliveOperandSets[numOperandSetsAllocated] = true;
-  ++numOperandSetsAllocated;
-  return set;
+irgen::IRGenModule *SwiftPassInvocation::getIRGenModule() {
+  return passManager->getIRGenModule();
 }
 
-void SwiftPassInvocation::freeOperandSet(OperandSet *set) {
-  int idx = set - (OperandSet *)operandSetStorage;
-  assert(idx >= 0 && idx < numOperandSetsAllocated);
-  assert(aliveOperandSets[idx] && "double free of OperandSet");
-  aliveOperandSets[idx] = false;
+SwiftPassInvocation::~SwiftPassInvocation() {}
 
-  while (numOperandSetsAllocated > 0 && !aliveOperandSets[numOperandSetsAllocated - 1]) {
-    auto *set = (OperandSet *)operandSetStorage + numOperandSetsAllocated - 1;
-    set->~OperandSet();
-    --numOperandSetsAllocated;
-  }
-}
+SILFunction *SwiftPassInvocation::
+createEmptyFunction(StringRef name,
+                    ArrayRef<SILParameterInfo> params,
+                    bool hasSelfParam,
+                    SILFunction *fromFn) {
+  CanSILFunctionType fTy = fromFn->getLoweredFunctionType();
+  assert(fromFn->getGenericSignature().isNull() && "generic functions are not supported");
 
-void SwiftPassInvocation::startModulePassRun(SILModuleTransform *transform) {
-  assert(!this->function && !this->transform && "a pass is already running");
-  this->function = nullptr;
-  this->transform = transform;
-}
+  auto extInfo = fTy->getExtInfo();
+  if (fTy->hasSelfParam() && !hasSelfParam)
+    extInfo = extInfo.withRepresentation(SILFunctionTypeRepresentation::Thin);
 
-void SwiftPassInvocation::startFunctionPassRun(SILFunctionTransform *transform) {
-  assert(!this->transform && "a pass is already running");
-  this->transform = transform;
-  beginTransformFunction(transform->getFunction());
-}
+  CanSILFunctionType newTy = SILFunctionType::get(
+      /*GenericSignature=*/nullptr, extInfo, fTy->getCoroutineKind(),
+      fTy->getCalleeConvention(), params, fTy->getYields(),
+      fTy->getResults(), fTy->getOptionalErrorResult(),
+      SubstitutionMap(), SubstitutionMap(),
+      getModule()->getASTContext());
 
-void SwiftPassInvocation::startInstructionPassRun(SILInstruction *inst) {
-  assert(inst->getFunction() == function &&
-         "running instruction pass on wrong function");
-}
+  SILOptFunctionBuilder functionBuilder(*getTransform());
 
-void SwiftPassInvocation::finishedModulePassRun() {
-  endPass();
-  assert(!function && transform && "not running a pass");
-  assert(changeNotifications == SILAnalysis::InvalidationKind::Nothing
-         && !functionTablesChanged
-         && "unhandled change notifications at end of module pass");
-  transform = nullptr;
-}
+  SILFunction *newF = functionBuilder.createFunction(
+      fromFn->getLinkage(), name, newTy, nullptr,
+      fromFn->getLocation(), fromFn->isBare(), fromFn->isTransparent(),
+      fromFn->getSerializedKind(), IsNotDynamic, IsNotDistributed,
+      IsNotRuntimeAccessible, fromFn->getEntryCount(), fromFn->isThunk(),
+      fromFn->getClassSubclassScope(), fromFn->getInlineStrategy(),
+      fromFn->getEffectsKind(), nullptr, fromFn->getDebugScope());
 
-void SwiftPassInvocation::finishedFunctionPassRun() {
-  endPass();
-  endTransformFunction();
-  assert(allocatedSlabs.empty() && "StackList is leaking slabs");
-  transform = nullptr;
+  return newF;
 }
 
-void SwiftPassInvocation::finishedInstructionPassRun() {
-  endPass();
+void SwiftPassInvocation::moveFunctionBody(SILFunction *sourceFn, SILFunction *destFn) {
+  destFn->moveAllBlocksFromOtherFunction(sourceFn);
+  getPassManager()->invalidateAnalysis(sourceFn, SILAnalysis::InvalidationKind::Everything);
+  getPassManager()->invalidateAnalysis(destFn, SILAnalysis::InvalidationKind::Everything);
 }
 
-irgen::IRGenModule *SwiftPassInvocation::getIRGenModule() {
-  return passManager->getIRGenModule();
-}
+SILFunction *SwiftPassInvocation::lookupStdlibFunction(StringRef name) {
+  SmallVector<ValueDecl *, 1> results;
+  getModule()->getASTContext().lookupInSwiftModule(name, results);
+  if (results.size() != 1)
+    return nullptr;
 
-void SwiftPassInvocation::endPass() {
-  assert(allocatedSlabs.empty() && "StackList is leaking slabs");
-  assert(numBlockSetsAllocated == 0 && "Not all BasicBlockSets deallocated");
-  assert(numNodeSetsAllocated == 0 && "Not all NodeSets deallocated");
-  assert(numOperandSetsAllocated == 0 && "Not all OperandSets deallocated");
-  assert(numClonersAllocated == 0 && "Not all cloners deallocated");
-  assert(!needFixStackNesting && "Stack nesting not fixed");
-  if (ssaUpdater) {
-    delete ssaUpdater;
-    ssaUpdater = nullptr;
-  }
-}
+  auto *decl = dyn_cast<FuncDecl>(results.front());
+  if (!decl)
+    return nullptr;
 
-void SwiftPassInvocation::beginTransformFunction(SILFunction *function) {
-  assert(!this->function && transform && "not running a pass");
-  assert(changeNotifications == SILAnalysis::InvalidationKind::Nothing
-         && !functionTablesChanged
-         && "change notifications not cleared");
-  this->function = function;
+  SILDeclRef declRef(decl, SILDeclRef::Kind::Func);
+  SILOptFunctionBuilder funcBuilder(*getTransform());
+  return funcBuilder.getOrCreateFunction(SILLocation(decl), declRef, NotForDefinition);
 }
 
-void SwiftPassInvocation::endTransformFunction() {
-  assert(function && transform && "not running a pass");
-  if (changeNotifications != SILAnalysis::InvalidationKind::Nothing) {
-    passManager->invalidateAnalysis(function, changeNotifications);
-    changeNotifications = SILAnalysis::InvalidationKind::Nothing;
-  }
-  if (functionTablesChanged) {
-    passManager->invalidateFunctionTables();
-    functionTablesChanged = false;
-  }
-  function = nullptr;
-  assert(numBlockSetsAllocated == 0 && "Not all BasicBlockSets deallocated");
-  assert(numNodeSetsAllocated == 0 && "Not all NodeSets deallocated");
-  assert(numOperandSetsAllocated == 0 && "Not all OperandSets deallocated");
+void SwiftPassInvocation::initializeSSAUpdater(SILFunction *function, SILType type, ValueOwnershipKind ownership) {
+  if (!ssaUpdater)
+    ssaUpdater = new SILSSAUpdater(&insertedPhisBySSAUpdater);
+  ssaUpdater->initialize(function, type, ownership);
 }
 
-void SwiftPassInvocation::beginVerifyFunction(SILFunction *function) {
-  if (transform) {
-    assert(this->function == function);
-  } else {
-    assert(!this->function);
-    this->function = function;
-  }
+void SwiftPassInvocation::SSAUpdater_addAvailableValue(SILBasicBlock *block, SILValue value) {
+  ssaUpdater->addAvailableValue(block, value);
 }
 
-void SwiftPassInvocation::endVerifyFunction() {
-  assert(function);
-  if (!transform) {
-    assert(changeNotifications == SILAnalysis::InvalidationKind::Nothing &&
-           !functionTablesChanged &&
-           "verifyication must not change the SIL of a function");
-    assert(numBlockSetsAllocated == 0 && "Not all BasicBlockSets deallocated");
-    assert(numNodeSetsAllocated == 0 && "Not all NodeSets deallocated");
-    assert(numOperandSetsAllocated == 0 && "Not all OperandSets deallocated");
-    function = nullptr;
-  }
+SILValue SwiftPassInvocation::SSAUpdater_getValueAtEndOfBlock(SILBasicBlock *block) {
+  return ssaUpdater->getValueAtEndOfBlock(block);
 }
 
-SwiftPassInvocation::~SwiftPassInvocation() {}
+SILValue SwiftPassInvocation::SSAUpdater_getValueInMiddleOfBlock(SILBasicBlock *block) {
+  return ssaUpdater->getValueInMiddleOfBlock(block);
+}
diff --git a/lib/SILOptimizer/PassManager/PassPipeline.cpp b/lib/SILOptimizer/PassManager/PassPipeline.cpp
index 92a084c2df588..3d08efc8bf489 100644
--- a/lib/SILOptimizer/PassManager/PassPipeline.cpp
+++ b/lib/SILOptimizer/PassManager/PassPipeline.cpp
@@ -62,6 +62,14 @@ static llvm::cl::opt<bool> SILViewSILGenCFG(
     "sil-view-silgen-cfg", llvm::cl::init(false),
     llvm::cl::desc("Enable the sil cfg viewer pass before diagnostics"));
 
+static llvm::cl::opt<bool> SILPrintSILGenModule(
+    "sil-print-silgen-module", llvm::cl::init(false),
+    llvm::cl::desc("Enable printing the module after SILGen"));
+
+static llvm::cl::opt<bool> SILPrintFinalModule(
+    "sil-print-final-module", llvm::cl::init(false),
+    llvm::cl::desc("Enable printing the module after all SIL passes"));
+
 //===----------------------------------------------------------------------===//
 //                          Diagnostic Pass Pipeline
 //===----------------------------------------------------------------------===//
@@ -109,7 +117,6 @@ static void addMandatoryDiagnosticOptPipeline(SILPassPipelinePlan &P) {
   P.startPipeline("Mandatory Diagnostic Passes + Enabling Optimization Passes");
   P.addDiagnoseInvalidEscapingCaptures();
   P.addReferenceBindingTransform();
-  P.addDiagnoseStaticExclusivity();
   P.addNestedSemanticFunctionCheck();
   P.addCapturePromotion();
 
@@ -117,15 +124,22 @@ static void addMandatoryDiagnosticOptPipeline(SILPassPipelinePlan &P) {
   // This guarantees that stack-promotable boxes have [static] enforcement.
   P.addAccessEnforcementSelection();
 
-  P.addAllocBoxToStack();
+#ifdef SWIFT_ENABLE_SWIFT_IN_SWIFT
+  P.addMandatoryAllocBoxToStack();
+#else
+  P.addLegacyAllocBoxToStack();
+#endif
+  // Needs to run after MandatoryAllocBoxToStack, because MandatoryAllocBoxToStack
+  // can convert dynamic accesses to static accesses.
+  P.addDiagnoseStaticExclusivity();
+
   P.addNoReturnFolding();
   P.addBooleanLiteralFolding();
   addDefiniteInitialization(P);
 
   P.addAddressLowering();
 
-  // Before we run later semantic optimizations, eliminate simple functions that
-  // we specialized to ensure that we do not emit diagnostics twice.
+  // TODO: remove this once CapturePromotion deletes specialized functions itself.
   P.addDiagnosticDeadFunctionElimination();
 
   P.addFlowIsolation();
@@ -241,7 +255,7 @@ static void addMandatoryDiagnosticOptPipeline(SILPassPipelinePlan &P) {
 
   // Only issue weak lifetime warnings for users who select object lifetime
   // optimization. The risk of spurious warnings outweighs the benefits.
-  if (P.getOptions().CopyPropagation == CopyPropagationOption::On) {
+  if (P.getOptions().CopyPropagation >= CopyPropagationOption::Optimizing) {
     P.addDiagnoseLifetimeIssues();
   }
 
@@ -263,7 +277,30 @@ static void addMandatoryDiagnosticOptPipeline(SILPassPipelinePlan &P) {
   }
 
   P.addDiagnoseUnknownConstValues();
+  P.addEmbeddedSwiftDiagnostics();
+
+  /// FIXME: Ideally, we'd have this relative order:
+  ///   1. DiagnoseLifetimeIssues
+  ///   2. CopyPropagation
+  ///   3. AddressLowering
+  /// to get the maximum benefits of CopyPropagation + OpaqueValues in -Onone.
+  if (P.getOptions().CopyPropagation == CopyPropagationOption::Always) {
+    // FIXME: ComputeSideEffects helps CopyPropagation simplify across
+    //   call-sites, but PerformanceDiagnostics is sensitive to the # of copies.
+    //   If ManualOwnership is used in the compiler itself, we wouldn't be able
+    //   to bootstrap the compiler on different platforms with same diagnostics.
+#ifdef SWIFT_ENABLE_SWIFT_IN_SWIFT
+    P.addComputeSideEffects();
+#endif
+    P.addMandatoryCopyPropagation();
+  }
+
   P.addPerformanceDiagnostics();
+
+  // Run inline(always) inlining at the end of the diagnostic pipeline.
+  // It is considered a diagnostics pass because it will diagnose cycles in
+  // inline(always) function calling.
+  P.addInlineAlwaysInlining();
 }
 
 SILPassPipelinePlan
@@ -279,6 +316,9 @@ SILPassPipelinePlan::getSILGenPassPipeline(const SILOptions &Options) {
   if (SILViewSILGenCFG) {
     addCFGPrinterPipeline(P, "SIL View SILGen CFG");
   }
+  if (SILPrintSILGenModule) {
+    addModulePrinterPipeline(P, "SIL Print SILGen Module");
+  }
   return P;
 }
 
@@ -377,7 +417,7 @@ void addHighLevelLoopOptPasses(SILPassPipelinePlan &P) {
   // before CanonicalOSSA re-hoists destroys.
   P.addAccessEnforcementReleaseSinking();
   P.addAccessEnforcementOpts();
-  P.addHighLevelLICM();
+  P.addLoopInvariantCodeMotion();
   // Simplify CFG after LICM that creates new exit blocks
   P.addSimplifyCFG();
   // LICM might have added new merging potential by hoisting
@@ -430,7 +470,7 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   P.addDCE();
 
   // Optimize copies from a temporary (an "l-value") to a destination.
-  P.addTempLValueOpt();
+  P.addTempLValueElimination();
 
   // Split up opaque operations (copy_addr, retain_value, etc.).
   P.addLowerAggregateInstrs();
@@ -466,7 +506,7 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   // late as possible before inlining because it must run between runs of the
   // inliner when the pipeline restarts.
   if (OpLevel == OptimizationLevelKind::MidLevel) {
-    P.addHighLevelLICM();
+    P.addLoopInvariantCodeMotion();
     P.addArrayCountPropagation();
     P.addBoundsCheckOpts();
     P.addDCE();
@@ -508,16 +548,6 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   P.addSemanticARCOpts();
   P.addCopyToBorrowOptimization();
 
-  if (!P.getOptions().EnableOSSAModules) {
-    if (P.getOptions().StopOptimizationBeforeLoweringOwnership)
-      return;
-
-    if (SILPrintFinalOSSAModule) {
-      addModulePrinterPipeline(P, "SIL Print Final OSSA Module");
-    }
-    P.addNonTransparentFunctionOwnershipModelEliminator();
-  }
-
   switch (OpLevel) {
   case OptimizationLevelKind::HighLevel:
     // Does not inline functions with defined semantics or effects.
@@ -531,13 +561,11 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   }
 
   // Clean up Semantic ARC before we perform additional post-inliner opts.
-  if (P.getOptions().EnableOSSAModules) {
-    if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
-      P.addCopyPropagation();
-    }
-    P.addSemanticARCOpts();
-    P.addCopyToBorrowOptimization();
+  if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
+    P.addCopyPropagation();
   }
+  P.addSemanticARCOpts();
+  P.addCopyToBorrowOptimization();
 
   // Promote stack allocations to values and eliminate redundant
   // loads.
@@ -579,7 +607,7 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   P.addEarlyCodeMotion();
   P.addReleaseHoisting();
   P.addARCSequenceOpts();
-  P.addTempRValueOpt();
+  P.addTempRValueElimination();
 
   P.addSimplifyCFG();
   if (OpLevel == OptimizationLevelKind::LowLevel) {
@@ -598,14 +626,12 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   P.addARCSequenceOpts();
 
   // Run a final round of ARC opts when ownership is enabled.
-  if (P.getOptions().EnableOSSAModules) {
-    P.addDestroyHoisting();
-    if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
-      P.addCopyPropagation();
-    }
-    P.addSemanticARCOpts();
-    P.addCopyToBorrowOptimization();
+  P.addDestroyHoisting();
+  if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
+    P.addCopyPropagation();
   }
+  P.addSemanticARCOpts();
+  P.addCopyToBorrowOptimization();
 }
 
 static void addPerfDebugSerializationPipeline(SILPassPipelinePlan &P) {
@@ -635,9 +661,9 @@ static void addPerfEarlyModulePassPipeline(SILPassPipelinePlan &P) {
   P.addDeadFunctionAndGlobalElimination();
 
   // Cleanup after SILGen: remove trivial copies to temporaries.
-  P.addTempRValueOpt();
+  P.addTempRValueElimination();
   // Cleanup after SILGen: remove unneeded borrows/copies.
-  if (P.getOptions().CopyPropagation == CopyPropagationOption::On) {
+  if (P.getOptions().CopyPropagation >= CopyPropagationOption::Optimizing) {
     P.addComputeSideEffects();
     P.addCopyPropagation();
   }
@@ -655,7 +681,7 @@ static void addPerfEarlyModulePassPipeline(SILPassPipelinePlan &P) {
   // Cleanup after SILGen: remove trivial copies to temporaries. This version of
   // temp-rvalue opt is here so that we can hit copies from non-ossa code that
   // is linked in from the stdlib.
-  P.addTempRValueOpt();
+  P.addTempRValueElimination();
 
   // Add the outliner pass (Osize).
   P.addOutliner();
@@ -724,10 +750,10 @@ static void addMidLevelFunctionPipeline(SILPassPipelinePlan &P) {
 
   // A LICM pass at mid-level is mainly needed to hoist addressors of globals.
   // It needs to be before global_init functions are inlined.
-  P.addLICM();
+  P.addLoopInvariantCodeMotion();
   // Run loop unrolling after inlining and constant propagation, because loop
   // trip counts may have became constant.
-  P.addLICM();
+  P.addLoopInvariantCodeMotion();
   P.addLoopUnroll();
 }
 
@@ -761,14 +787,10 @@ static void addClosureSpecializePassPipeline(SILPassPipelinePlan &P) {
   // ClosureSpecialization, because constant propagation is more effective.  At
   // least one round of SSA optimization and inlining should run after this to
   // take advantage of static dispatch.
-  P.addCapturePropagation();
+  P.addConstantCapturePropagation();
 
-  // Specialize closure.
-  if (P.getOptions().EnableExperimentalSwiftBasedClosureSpecialization) {
-    P.addExperimentalSwiftBasedClosureSpecialization();
-  } else {
-    P.addClosureSpecializer();
-  }
+  // TODO: replace this with the new ClosureSpecialization pass once we have OSSA at this point in the pipeline
+  P.addClosureSpecializer();
 
   // Do the second stack promotion on low-level SIL.
   P.addStackPromotion();
@@ -833,7 +855,7 @@ static void addLateLoopOptPassPipeline(SILPassPipelinePlan &P) {
   // It will also set the no_nested_conflict for dynamic accesses
   P.addAccessEnforcementReleaseSinking();
   P.addAccessEnforcementOpts();
-  P.addLICM();
+  P.addLoopInvariantCodeMotion();
   P.addCOWOpts();
   // Simplify CFG after LICM that creates new exit blocks
   P.addSimplifyCFG();
@@ -877,7 +899,7 @@ static void addLastChanceOptPassPipeline(SILPassPipelinePlan &P) {
   P.addAccessEnforcementDom();
   // addAccessEnforcementDom might provide potential for LICM:
   // A loop might have only one dynamic access now, i.e. hoistable
-  P.addLICM();
+  P.addLoopInvariantCodeMotion();
 
   // Verify AccessStorage once again after optimizing and lowering OSSA.
 #ifndef NDEBUG
@@ -987,13 +1009,11 @@ SILPassPipelinePlan::getPerformancePassPipeline(const SILOptions &Options) {
 
   // Run one last copy propagation/semantic arc opts run before serialization/us
   // lowering ownership.
-  if (P.getOptions().EnableOSSAModules) {
-    if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
-      P.addCopyPropagation();
-    }
-    P.addSemanticARCOpts();
-    P.addCopyToBorrowOptimization();
+  if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
+    P.addCopyPropagation();
   }
+  P.addSemanticARCOpts();
+  P.addCopyToBorrowOptimization();
 
   P.addCrossModuleOptimization();
 
@@ -1007,14 +1027,13 @@ SILPassPipelinePlan::getPerformancePassPipeline(const SILOptions &Options) {
   if (Options.StopOptimizationAfterSerialization)
     return P;
 
-  if (P.getOptions().EnableOSSAModules && SILPrintFinalOSSAModule) {
+  if (SILPrintFinalOSSAModule) {
     addModulePrinterPipeline(P, "SIL Print Final OSSA Module");
   }
-  // Strip any transparent functions that still have ownership.
-  P.addOwnershipModelEliminator();
-
   P.addAutodiffClosureSpecialization();
 
+  P.addOwnershipModelEliminator();
+
   // After serialization run the function pass pipeline to iteratively lower
   // high-level constructs like @_semantics calls.
   addMidLevelFunctionPipeline(P);
@@ -1040,6 +1059,9 @@ SILPassPipelinePlan::getPerformancePassPipeline(const SILOptions &Options) {
   if (SILViewCFG) {
     addCFGPrinterPipeline(P, "SIL Before IRGen View CFG");
   }
+  if (SILPrintFinalModule) {
+    addModulePrinterPipeline(P, "SIL Print Final Module");
+  }
 
   return P;
 }
@@ -1081,11 +1103,13 @@ SILPassPipelinePlan::getOnonePassPipeline(const SILOptions &Options) {
   // Now that we have serialized, propagate debug info.
   P.addMovedAsyncVarDebugInfoPropagator();
 
+  // Even at Onone it's important to remove copies of structs, especially if they are large.
+  P.addMandatoryTempRValueElimination();
+
   // If we are asked to stop optimizing before lowering ownership, do so now.
   if (P.Options.StopOptimizationBeforeLoweringOwnership)
     return P;
 
-  // Now strip any transparent functions that still have ownership.
   P.addOwnershipModelEliminator();
 
   // Finally perform some small transforms.
@@ -1120,6 +1144,9 @@ SILPassPipelinePlan::getOnonePassPipeline(const SILOptions &Options) {
   // Has only an effect if the -sil-based-debuginfo option is specified.
   P.addSILDebugInfoGenerator();
 
+  if (SILPrintFinalModule) {
+    addModulePrinterPipeline(P, "SIL Print Final Module");
+  }
   return P;
 }
 
diff --git a/lib/SILOptimizer/PassManager/Passes.cpp b/lib/SILOptimizer/PassManager/Passes.cpp
index d5b6c1c387ba8..deaeb69423543 100644
--- a/lib/SILOptimizer/PassManager/Passes.cpp
+++ b/lib/SILOptimizer/PassManager/Passes.cpp
@@ -239,8 +239,9 @@ static void runBridgedModulePass(BridgedModulePassRunFn &runFunction,
     runFunction = bridgedModulePassRunFunctions[passName];
     if (!runFunction) {
       if (passesRegistered) {
-        llvm::errs() << "Swift pass " << passName << " is not registered\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Swift pass " << passName << " is not registered";
+        });
       }
       return;
     }
@@ -259,15 +260,15 @@ static void runBridgedFunctionPass(BridgedFunctionPassRunFn &runFunction,
     runFunction = bridgedFunctionPassRunFunctions[passName];
     if (!runFunction) {
       if (passesRegistered) {
-        llvm::errs() << "Swift pass " << passName << " is not registered\n";
-        abort();
+        ABORT([&](auto &out) {
+          out << "Swift pass " << passName << " is not registered";
+        });
       }
       return;
     }
   }
   if (!f->isBridged()) {
-    llvm::errs() << "SILFunction metatype is not registered\n";
-    abort();
+    ABORT("SILFunction metatype is not registered");
   }
   runFunction({{f}, {passManager->getSwiftPassInvocation()}});
 }
diff --git a/lib/SILOptimizer/SILCombiner/SILCombine.cpp b/lib/SILOptimizer/SILCombiner/SILCombine.cpp
index 459d32f468266..51eab585e2770 100644
--- a/lib/SILOptimizer/SILCombiner/SILCombine.cpp
+++ b/lib/SILOptimizer/SILCombiner/SILCombine.cpp
@@ -33,11 +33,11 @@
 #include "swift/SILOptimizer/Analysis/SimplifyInstruction.h"
 #include "swift/SILOptimizer/PassManager/PassManager.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h"
 #include "swift/SILOptimizer/Utils/CanonicalizeInstruction.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/DebugOptUtils.h"
 #include "swift/SILOptimizer/Utils/InstOptUtils.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "swift/SILOptimizer/Utils/SILOptFunctionBuilder.h"
 #include "swift/SILOptimizer/Utils/StackNesting.h"
 #include "llvm/ADT/SmallPtrSet.h"
@@ -311,7 +311,7 @@ void SILCombiner::canonicalizeOSSALifetimes(SILInstruction *currentInst) {
   // copyInst was either optimized by a SILCombine visitor or is a copy_value
   // produced by the visitor. Find the canonical def.
   auto recordCopiedDef = [&defsToCanonicalize](CopyValueInst *copyInst) {
-    SILValue def = CanonicalizeOSSALifetime::getCanonicalCopiedDef(copyInst);
+    SILValue def = OSSACanonicalizeOwned::getCanonicalCopiedDef(copyInst);
 
     // getCanonicalCopiedDef returns a copy whenever that the copy's source is
     // guaranteed. In that case, find the root of the borrowed lifetime. If it
@@ -325,8 +325,9 @@ void SILCombiner::canonicalizeOSSALifetimes(SILInstruction *currentInst) {
     // fast convergence, rewriting borrow scopes should not be combined with
     // other unrelated transformations.
     if (auto *copyDef = dyn_cast<CopyValueInst>(def)) {
-      if (SILValue borrowDef = CanonicalizeBorrowScope::getCanonicalBorrowedDef(
-              copyDef->getOperand())) {
+      if (SILValue borrowDef =
+              OSSACanonicalizeGuaranteed::getCanonicalBorrowedDef(
+                  copyDef->getOperand())) {
         if (isa<SILFunctionArgument>(borrowDef)) {
           def = borrowDef;
         }
@@ -348,7 +349,7 @@ void SILCombiner::canonicalizeOSSALifetimes(SILInstruction *currentInst) {
     return;
 
   // Remove instructions deleted during canonicalization from SILCombine's
-  // worklist. CanonicalizeOSSALifetime invalidates operands before invoking
+  // worklist. OSSACanonicalizeOwned invalidates operands before invoking
   // the deletion callback.
   auto canonicalizeCallbacks =
       InstModCallbacks().onDelete([this](SILInstruction *instToDelete) {
@@ -358,12 +359,12 @@ void SILCombiner::canonicalizeOSSALifetimes(SILInstruction *currentInst) {
   InstructionDeleter deleter(std::move(canonicalizeCallbacks));
 
   DominanceInfo *domTree = DA->get(&Builder.getFunction());
-  CanonicalizeOSSALifetime canonicalizer(
+  OSSACanonicalizeOwned canonicalizer(
       DontPruneDebugInsts,
       MaximizeLifetime_t(!parentTransform->getFunction()->shouldOptimize()),
       parentTransform->getFunction(), NLABA, DEBA, domTree, CA, deleter);
-  CanonicalizeBorrowScope borrowCanonicalizer(parentTransform->getFunction(),
-                                              deleter);
+  OSSACanonicalizeGuaranteed borrowCanonicalizer(parentTransform->getFunction(),
+                                                 deleter);
 
   while (!defsToCanonicalize.empty()) {
     SILValue def = defsToCanonicalize.pop_back_val();
@@ -613,28 +614,29 @@ void SILCombine_registerInstructionPass(BridgedStringRef instClassName,
   passesRegistered = true;
 }
 
-#define _RUN_SWIFT_SIMPLIFICATON(INST) \
-  static BridgedInstructionPassRunFn runFunction = nullptr;                \
-  static bool passDisabled = false;                                        \
-  if (!runFunction) {                                                      \
-    runFunction = swiftInstPasses[#INST];                                  \
-    if (!runFunction) {                                                    \
-      if (passesRegistered) {                                              \
-        llvm::errs() << "Swift pass " << #INST << " is not registered\n";  \
-        abort();                                                           \
-      } else {                                                             \
-        return nullptr;                                                    \
-      }                                                                    \
-    }                                                                      \
-    StringRef instName = getSILInstructionName(SILInstructionKind::INST);  \
-    passDisabled = SILPassManager::isInstructionPassDisabled(instName);    \
-  }                                                                        \
-  if (passDisabled &&                                                      \
-      SILPassManager::disablePassesForFunction(inst->getFunction())) {     \
-    return nullptr;                                                        \
-  }                                                                        \
-  runSwiftInstructionPass(inst, runFunction);                              \
-  return nullptr;                                                          \
+#define _RUN_SWIFT_SIMPLIFICATON(INST)                                         \
+  static BridgedInstructionPassRunFn runFunction = nullptr;                    \
+  static bool passDisabled = false;                                            \
+  if (!runFunction) {                                                          \
+    runFunction = swiftInstPasses[#INST];                                      \
+    if (!runFunction) {                                                        \
+      if (passesRegistered) {                                                  \
+        ABORT([&](auto &out) {                                                 \
+          out << "Swift pass " << #INST << " is not registered";               \
+        });                                                                    \
+      } else {                                                                 \
+        return nullptr;                                                        \
+      }                                                                        \
+    }                                                                          \
+    StringRef instName = getSILInstructionName(SILInstructionKind::INST);      \
+    passDisabled = SILPassManager::isInstructionPassDisabled(instName);        \
+  }                                                                            \
+  if (passDisabled &&                                                          \
+      SILPassManager::disablePassesForFunction(inst->getFunction())) {         \
+    return nullptr;                                                            \
+  }                                                                            \
+  runSwiftInstructionPass(inst, runFunction);                                  \
+  return nullptr;
 
 #define INSTRUCTION_SIMPLIFICATION(INST) \
 SILInstruction *SILCombiner::visit##INST(INST *inst) {                     \
@@ -666,11 +668,9 @@ class SILCombine : public SILFunctionTransform {
   /// The entry point to the transformation.
   void run() override {
     bool enableCopyPropagation =
-        getOptions().CopyPropagation == CopyPropagationOption::On;
-    if (getOptions().EnableOSSAModules) {
-      enableCopyPropagation =
-          getOptions().CopyPropagation != CopyPropagationOption::Off;
-    }
+        getOptions().CopyPropagation >= CopyPropagationOption::Optimizing;
+    enableCopyPropagation =
+        getOptions().CopyPropagation != CopyPropagationOption::Off;
 
     SILCombiner Combiner(this, getOptions().RemoveRuntimeAsserts,
                          enableCopyPropagation);
@@ -694,11 +694,13 @@ SILTransform *swift::createSILCombine() {
 //                          SwiftFunctionPassContext
 //===----------------------------------------------------------------------===//
 
-void SwiftPassInvocation::eraseInstruction(SILInstruction *inst) {
+void SwiftPassInvocation::eraseInstruction(SILInstruction *inst, bool salvageDebugInfo) {
   if (silCombiner) {
-    silCombiner->eraseInstFromFunction(*inst);
+    silCombiner->eraseInstFromFunction(*inst, /*addOperandsToWorklist=*/ true, salvageDebugInfo);
   } else {
-    swift::salvageDebugInfo(inst);
+    if (salvageDebugInfo) {
+      swift::salvageDebugInfo(inst);
+    }
     if (inst->isStaticInitializerInst()) {
       inst->getParent()->erase(inst, *getPassManager()->getModule());
     } else {
diff --git a/lib/SILOptimizer/SILCombiner/SILCombiner.h b/lib/SILOptimizer/SILCombiner/SILCombiner.h
index 5f5de2e0bb1bc..a884295da361f 100644
--- a/lib/SILOptimizer/SILCombiner/SILCombiner.h
+++ b/lib/SILOptimizer/SILCombiner/SILCombiner.h
@@ -220,8 +220,10 @@ class SILCombiner :
   // by this method.
   SILInstruction *eraseInstFromFunction(SILInstruction &I,
                                         SILBasicBlock::iterator &InstIter,
-                                        bool AddOperandsToWorklist = true) {
-    Worklist.eraseInstFromFunction(I, InstIter, AddOperandsToWorklist);
+                                        bool AddOperandsToWorklist = true,
+                                        bool salvageDebugInfo = true) {
+    Worklist.eraseInstFromFunction(I, InstIter, AddOperandsToWorklist,
+                                   salvageDebugInfo);
     MadeChange = true;
     // Dummy return, so the caller doesn't need to explicitly return nullptr.
     return nullptr;
@@ -232,9 +234,10 @@ class SILCombiner :
   void eraseInstIncludingUsers(SILInstruction *inst);
 
   SILInstruction *eraseInstFromFunction(SILInstruction &I,
-                                        bool AddOperandsToWorklist = true) {
+                                        bool AddOperandsToWorklist = true,
+                                        bool salvageDebugInfo = true) {
     SILBasicBlock::iterator nullIter;
-    return eraseInstFromFunction(I, nullIter, AddOperandsToWorklist);
+    return eraseInstFromFunction(I, nullIter, AddOperandsToWorklist, salvageDebugInfo);
   }
 
   void addInitialGroup(ArrayRef<SILInstruction *> List) {
@@ -248,7 +251,6 @@ class SILCombiner :
   SILInstruction *visitPartialApplyInst(PartialApplyInst *AI);
   SILInstruction *visitBeginApplyInst(BeginApplyInst *BAI);
   SILInstruction *optimizeStringObject(BuiltinInst *BI);
-  SILInstruction *visitBuiltinInst(BuiltinInst *BI);
   SILInstruction *visitCondFailInst(CondFailInst *CFI);
   SILInstruction *visitRefToRawPointerInst(RefToRawPointerInst *RRPI);
   SILInstruction *visitUpcastInst(UpcastInst *UCI);
@@ -260,7 +262,6 @@ class SILCombiner :
   bool optimizeStackAllocatedEnum(AllocStackInst *AS);
   SILInstruction *visitSwitchEnumAddrInst(SwitchEnumAddrInst *SEAI);
   SILInstruction *visitInjectEnumAddrInst(InjectEnumAddrInst *IEAI);
-  SILInstruction *visitUncheckedAddrCastInst(UncheckedAddrCastInst *UADCI);
   SILInstruction *visitUncheckedRefCastInst(UncheckedRefCastInst *URCI);
   SILInstruction *visitEndCOWMutationInst(EndCOWMutationInst *URCI);
   SILInstruction *visitUncheckedRefCastAddrInst(UncheckedRefCastAddrInst *URCI);
@@ -289,8 +290,6 @@ class SILCombiner :
   SILInstruction *visitUnreachableInst(UnreachableInst *UI);
   SILInstruction *visitAllocRefDynamicInst(AllocRefDynamicInst *ARDI);
       
-  SILInstruction *visitMarkDependenceInst(MarkDependenceInst *MDI);
-  SILInstruction *visitMarkDependenceAddrInst(MarkDependenceAddrInst *MDI);
   SILInstruction *visitConvertFunctionInst(ConvertFunctionInst *CFI);
   SILInstruction *
   visitConvertEscapeToNoEscapeInst(ConvertEscapeToNoEscapeInst *Cvt);
@@ -342,7 +341,7 @@ class SILCombiner :
   /// try to visit it.
   bool trySinkOwnedForwardingInst(SingleValueInstruction *svi);
 
-  /// Apply CanonicalizeOSSALifetime to the extended lifetime of any copy
+  /// Apply OSSACanonicalizeOwned to the extended lifetime of any copy
   /// introduced during SILCombine for an owned value.
   void canonicalizeOSSALifetimes(SILInstruction *currentInst);
 
diff --git a/lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp b/lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp
index 49b6e762f0f9d..fd0187fa22a5b 100644
--- a/lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp
+++ b/lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp
@@ -172,6 +172,18 @@ SILCombiner::optimizeApplyOfConvertFunctionInst(FullApplySite AI,
   auto oldOpParamTypes = substConventions.getParameterSILTypes(context);
   auto newOpParamTypes = convertConventions.getParameterSILTypes(context);
 
+  // Currently we cannot deal with generic arguments/returns. Bail in this case.
+  for (auto newRetTy : newOpRetTypes) {
+    if (newRetTy.hasTypeParameter())
+      return nullptr;
+  }
+  for (auto newParamTy : newOpParamTypes) {
+    if (newParamTy.hasTypeParameter())
+      return nullptr;
+  }
+  if (newIndirectErrorResultType && newIndirectErrorResultType.hasTypeParameter())
+    return nullptr;
+
   llvm::SmallVector<SILValue, 8> Args;
   llvm::SmallVector<BeginBorrowInst *, 8> Borrows;
   auto convertOp = [&](SILValue Op, SILType OldOpType, SILType NewOpType,
@@ -1222,23 +1234,11 @@ SILInstruction *SILCombiner::createApplyWithConcreteType(
         NewArgs.push_back(cast);
         // Form a new set of substitutions where the argument is
         // replaced with a concrete type.
-        NewCallSubs = NewCallSubs.subst(
-            [&](SubstitutableType *type) -> Type {
-              if (type == OAI.OpenedArchetype)
-                return CEI.ConcreteType;
-              return type;
-            },
-            [&](CanType origTy, Type substTy,
-                ProtocolDecl *proto) -> ProtocolConformanceRef {
-              if (origTy->isEqual(OAI.OpenedArchetype)) {
-                assert(substTy->isEqual(CEI.ConcreteType));
-                // Do a conformance lookup on this witness requirement using the
-                // existential's conformances. The witness requirement may be a
-                // base type of the existential's requirements.
-                return CEI.lookupExistentialConformance(proto);
-              }
-              return ProtocolConformanceRef::forAbstract(substTy, proto);
-            }, SubstFlags::SubstituteLocalArchetypes);
+        ReplaceExistentialArchetypesWithConcreteTypes replacer(
+            OAI.OpenedArchetype->getGenericEnvironment(),
+            CEI.ExistentialSubs);
+        NewCallSubs = NewCallSubs.subst(replacer, replacer,
+                                        SubstFlags::SubstituteLocalArchetypes);
         continue;
       }
       // Otherwise, use the original argument.
@@ -1263,23 +1263,11 @@ SILInstruction *SILCombiner::createApplyWithConcreteType(
 
     // Form a new set of substitutions where the argument is
     // replaced with a concrete type.
-    NewCallSubs = NewCallSubs.subst(
-        [&](SubstitutableType *type) -> Type {
-          if (type == OAI.OpenedArchetype)
-            return CEI.ConcreteType;
-          return type;
-        },
-        [&](CanType origTy, Type substTy,
-            ProtocolDecl *proto) -> ProtocolConformanceRef {
-          if (origTy->isEqual(OAI.OpenedArchetype)) {
-            assert(substTy->isEqual(CEI.ConcreteType));
-            // Do a conformance lookup on this witness requirement using the
-            // existential's conformances. The witness requirement may be a
-            // base type of the existential's requirements.
-            return CEI.lookupExistentialConformance(proto);
-          }
-          return ProtocolConformanceRef::forAbstract(substTy, proto);
-        }, SubstFlags::SubstituteLocalArchetypes);
+    ReplaceExistentialArchetypesWithConcreteTypes replacer(
+        OAI.OpenedArchetype->getGenericEnvironment(),
+        CEI.ExistentialSubs);
+    NewCallSubs = NewCallSubs.subst(replacer, replacer,
+                                    SubstFlags::SubstituteLocalArchetypes);
   }
 
   // We need to make sure that we can a) update Apply to use the new args and b)
@@ -1544,8 +1532,14 @@ SILInstruction *SILCombiner::legacyVisitApplyInst(ApplyInst *AI) {
     return nullptr;
 
   SILValue callee = AI->getCallee();
-  if (auto *cee = dyn_cast<ConvertEscapeToNoEscapeInst>(callee)) {
-    callee = cee->getOperand();
+  for (;;) {
+    if (auto *cee = dyn_cast<ConvertEscapeToNoEscapeInst>(callee)) {
+      callee = cee->getOperand();
+    } else if (auto *mdi = dyn_cast<MarkDependenceInst>(callee)) {
+      callee = mdi->getValue();
+    } else {
+      break;
+    }
   }
   if (auto *CFI = dyn_cast<ConvertFunctionInst>(callee))
     return optimizeApplyOfConvertFunctionInst(AI, CFI);
diff --git a/lib/SILOptimizer/SILCombiner/SILCombinerBuiltinVisitors.cpp b/lib/SILOptimizer/SILCombiner/SILCombinerBuiltinVisitors.cpp
index 2a4e0235f727f..dd12c5027899f 100644
--- a/lib/SILOptimizer/SILCombiner/SILCombinerBuiltinVisitors.cpp
+++ b/lib/SILOptimizer/SILCombiner/SILCombinerBuiltinVisitors.cpp
@@ -659,7 +659,7 @@ SILInstruction *SILCombiner::optimizeStringObject(BuiltinInst *BI) {
                                       setBits & andBits);
 }
 
-SILInstruction *SILCombiner::visitBuiltinInst(BuiltinInst *I) {
+SILInstruction *SILCombiner::legacyVisitBuiltinInst(BuiltinInst *I) {
   if (I->getBuiltinInfo().ID == BuiltinValueKind::CanBeObjCClass)
     return optimizeBuiltinCanBeObjCClass(I, Builder);
   if (I->getBuiltinInfo().ID == BuiltinValueKind::IsConcrete)
diff --git a/lib/SILOptimizer/SILCombiner/SILCombinerCastVisitors.cpp b/lib/SILOptimizer/SILCombiner/SILCombinerCastVisitors.cpp
index 9e28834bb1c27..09f14c969e1a4 100644
--- a/lib/SILOptimizer/SILCombiner/SILCombinerCastVisitors.cpp
+++ b/lib/SILOptimizer/SILCombiner/SILCombinerCastVisitors.cpp
@@ -219,23 +219,6 @@ SILInstruction *SILCombiner::visitUpcastInst(UpcastInst *uci) {
   return nullptr;
 }
 
-SILInstruction *
-SILCombiner::visitUncheckedAddrCastInst(UncheckedAddrCastInst *UADCI) {
-  // These are always safe to perform due to interior pointer ownership
-  // requirements being transitive along addresses.
-
-  Builder.setCurrentDebugScope(UADCI->getDebugScope());
-
-  // (unchecked_addr_cast (unchecked_addr_cast x X->Y) Y->Z)
-  //   ->
-  // (unchecked_addr_cast x X->Z)
-  if (auto *OtherUADCI = dyn_cast<UncheckedAddrCastInst>(UADCI->getOperand()))
-    return Builder.createUncheckedAddrCast(UADCI->getLoc(),
-                                           OtherUADCI->getOperand(),
-                                           UADCI->getType());
-  return nullptr;
-}
-
 SILInstruction *
 SILCombiner::visitUncheckedRefCastInst(UncheckedRefCastInst *urci) {
   // %0 = unchecked_ref_cast %x : $X->Y
diff --git a/lib/SILOptimizer/SILCombiner/SILCombinerMiscVisitors.cpp b/lib/SILOptimizer/SILCombiner/SILCombinerMiscVisitors.cpp
index 29bc111fcf678..e5cf557d72a81 100644
--- a/lib/SILOptimizer/SILCombiner/SILCombinerMiscVisitors.cpp
+++ b/lib/SILOptimizer/SILCombiner/SILCombinerMiscVisitors.cpp
@@ -1059,7 +1059,7 @@ SILCombiner::visitInjectEnumAddrInst(InjectEnumAddrInst *IEAI) {
         Builder.getBuilderContext(), /*noUndef*/ true);
   } else {
     auto loadQual = !func->hasOwnership() ? LoadOwnershipQualifier::Unqualified
-                    : DataAddrInst->getOperand()->getType().isTrivial(*func)
+                    : DataAddrInst->getType().isTrivial(*func)
                         ? LoadOwnershipQualifier::Trivial
                         : LoadOwnershipQualifier::Take;
     enumValue =
@@ -1118,12 +1118,17 @@ SILInstruction *SILCombiner::visitUncheckedTakeEnumDataAddrInst(
     return nullptr;
 
   bool onlyLoads = true;
+  bool anyLoadCopies = false;
   bool onlyDestroys = true;
   for (auto U : getNonDebugUses(tedai)) {
     // Check if it is load. If it is not a load, bail...
     if (!isa<LoadInst>(U->getUser()) && !isa<LoadBorrowInst>(U->getUser()))
       onlyLoads = false;
 
+    if (auto *li = dyn_cast<LoadInst>(U->getUser()))
+      if (li->getOwnershipQualifier() == LoadOwnershipQualifier::Copy)
+        anyLoadCopies = true;
+
     // If we have a load_borrow, perform an additional check that we do not have
     // any reborrow uses. We do not handle reborrows in this optimization.
     if (auto *lbi = dyn_cast<LoadBorrowInst>(U->getUser())) {
@@ -1166,6 +1171,11 @@ SILInstruction *SILCombiner::visitUncheckedTakeEnumDataAddrInst(
   if (tedai->getOperand()->getType().isAddressOnly(*tedai->getFunction()))
     return nullptr;
 
+  // If the enum is noncopyable and any loads cause copies, the transformation
+  // would be illegal because it would introduce a copy of the noncopyable enum.
+  if (tedai->getOperand()->getType().isMoveOnly() && anyLoadCopies)
+    return nullptr;
+
   // Grab the EnumAddr.
   SILLocation loc = tedai->getLoc();
   Builder.setCurrentDebugScope(tedai->getDebugScope());
@@ -1641,90 +1651,6 @@ visitAllocRefDynamicInst(AllocRefDynamicInst *ARDI) {
   return NewInst;
 }
 
-/// Returns true if \p val is a literal instruction or a struct of a literal
-/// instruction.
-/// What we want to catch here is a UnsafePointer<Int8> of a string literal.
-static bool isLiteral(SILValue val) {
-  while (auto *str = dyn_cast<StructInst>(val)) {
-    if (str->getNumOperands() != 1)
-      return false;
-    val = str->getOperand(0);
-  }
-  return isa<LiteralInst>(val);
-}
-
-template<SILInstructionKind Opc, typename Derived>
-static SILInstruction *combineMarkDependenceBaseInst(
-  MarkDependenceInstBase<Opc, Derived> *mdi,
-  SILCombiner *C) {
-  
-  if (!mdi->getFunction()->hasOwnership()) {
-    // Simplify the base operand of a MarkDependenceInst to eliminate
-    // unnecessary instructions that aren't adding value.
-    //
-    // Conversions to Optional.Some(x) often happen here, this isn't important
-    // for us, we can just depend on 'x' directly.
-    if (auto *eiBase = dyn_cast<EnumInst>(mdi->getBase())) {
-      if (eiBase->hasOperand()) {
-        mdi->setBase(eiBase->getOperand());
-        if (eiBase->use_empty()) {
-          C->eraseInstFromFunction(*eiBase);
-        }
-        return mdi;
-      }
-    }
-
-    // Conversions from a class to AnyObject also happen a lot, we can just
-    // depend on the class reference.
-    if (auto *ier = dyn_cast<InitExistentialRefInst>(mdi->getBase())) {
-      mdi->setBase(ier->getOperand());
-      if (ier->use_empty())
-        C->eraseInstFromFunction(*ier);
-      return mdi;
-    }
-
-    // Conversions from a class to AnyObject also happen a lot, we can just
-    // depend on the class reference.
-    if (auto *oeri = dyn_cast<OpenExistentialRefInst>(mdi->getBase())) {
-      mdi->setBase(oeri->getOperand());
-      if (oeri->use_empty())
-        C->eraseInstFromFunction(*oeri);
-      return mdi;
-    }
-  }
-
-  // Sometimes due to specialization/builtins, we can get a mark_dependence
-  // whose base is a trivial typed object. In such a case, the mark_dependence
-  // does not have a meaning, so just eliminate it.
-  {
-    SILType baseType = mdi->getBase()->getType();
-    if (baseType.getObjectType().isTrivial(*mdi->getFunction())) {
-      if (auto mdValue = dyn_cast<MarkDependenceInst>(mdi)) {
-        auto &valOper = mdi->getAllOperands()[MarkDependenceInst::Dependent];
-        mdValue->replaceAllUsesWith(valOper.get());
-      }
-      return C->eraseInstFromFunction(*mdi);
-    }
-  }
-  return nullptr;
-}
-
-SILInstruction *SILCombiner::visitMarkDependenceInst(MarkDependenceInst *mdi) {
-  if (isLiteral(mdi->getValue())) {
-    // A literal lives forever, so no mark_dependence is needed.
-    // This pattern can occur after StringOptimization when a utf8CString of
-    // a literal is replace by the string_literal itself.
-    replaceInstUsesWith(*mdi, mdi->getValue());
-    return eraseInstFromFunction(*mdi);
-  }
-  return combineMarkDependenceBaseInst(mdi, this);
-}
-
-SILInstruction *
-SILCombiner::visitMarkDependenceAddrInst(MarkDependenceAddrInst *mdi) {
-  return combineMarkDependenceBaseInst(mdi, this);
-}
-
 /// Returns true if reference counting and debug_value users of a global_value
 /// can be deleted.
 static bool checkGlobalValueUsers(SILValue val,
diff --git a/lib/SILOptimizer/SILCombiner/Simplifications.def b/lib/SILOptimizer/SILCombiner/Simplifications.def
index 5186a40053e2e..f00259dbb195a 100644
--- a/lib/SILOptimizer/SILCombiner/Simplifications.def
+++ b/lib/SILOptimizer/SILCombiner/Simplifications.def
@@ -32,8 +32,11 @@
 INSTRUCTION_SIMPLIFICATION(BeginBorrowInst)
 INSTRUCTION_SIMPLIFICATION(BeginCOWMutationInst)
 INSTRUCTION_SIMPLIFICATION(ClassifyBridgeObjectInst)
+INSTRUCTION_SIMPLIFICATION(ExplicitCopyAddrInst)
+INSTRUCTION_SIMPLIFICATION(ExplicitCopyValueInst)
 INSTRUCTION_SIMPLIFICATION(FixLifetimeInst)
 INSTRUCTION_SIMPLIFICATION(GlobalValueInst)
+INSTRUCTION_SIMPLIFICATION(StructInst)
 INSTRUCTION_SIMPLIFICATION(StrongRetainInst)
 INSTRUCTION_SIMPLIFICATION(StrongReleaseInst)
 INSTRUCTION_SIMPLIFICATION(RetainValueInst)
@@ -41,14 +44,20 @@ INSTRUCTION_SIMPLIFICATION(ReleaseValueInst)
 INSTRUCTION_SIMPLIFICATION(LoadInst)
 INSTRUCTION_SIMPLIFICATION(LoadBorrowInst)
 INSTRUCTION_SIMPLIFICATION(CopyValueInst)
+INSTRUCTION_SIMPLIFICATION(CopyBlockInst)
 INSTRUCTION_SIMPLIFICATION(DestroyValueInst)
 INSTRUCTION_SIMPLIFICATION(DestructureStructInst)
 INSTRUCTION_SIMPLIFICATION(DestructureTupleInst)
+INSTRUCTION_SIMPLIFICATION(MarkDependenceInst)
+INSTRUCTION_SIMPLIFICATION(MarkDependenceAddrInst)
 INSTRUCTION_SIMPLIFICATION(PointerToAddressInst)
 INSTRUCTION_SIMPLIFICATION(TypeValueInst)
+INSTRUCTION_SIMPLIFICATION(UncheckedAddrCastInst)
 INSTRUCTION_SIMPLIFICATION(UncheckedEnumDataInst)
 INSTRUCTION_SIMPLIFICATION(WitnessMethodInst)
+INSTRUCTION_SIMPLIFICATION(EndCOWMutationAddrInst)
 INSTRUCTION_SIMPLIFICATION_WITH_LEGACY(AllocStackInst)
+INSTRUCTION_SIMPLIFICATION_WITH_LEGACY(BuiltinInst)
 INSTRUCTION_SIMPLIFICATION_WITH_LEGACY(UnconditionalCheckedCastInst)
 INSTRUCTION_SIMPLIFICATION_WITH_LEGACY(ApplyInst)
 INSTRUCTION_SIMPLIFICATION_WITH_LEGACY(TryApplyInst)
diff --git a/lib/SILOptimizer/SemanticARC/Context.h b/lib/SILOptimizer/SemanticARC/Context.h
index b403d9b6149ee..e9aabf7fe4cd2 100644
--- a/lib/SILOptimizer/SemanticARC/Context.h
+++ b/lib/SILOptimizer/SemanticARC/Context.h
@@ -129,16 +129,9 @@ struct LLVM_LIBRARY_VISIBILITY Context {
   void verify() const;
 
   bool shouldPerform(ARCTransformKind testKind) const {
-    // When asserts are enabled, we allow for specific arc transforms to be
-    // turned on/off via LLVM args. So check that if we have asserts, perform
-    // all optimizations otherwise.
-#ifndef NDEBUG
     if (transformKind == ARCTransformKind::Invalid)
       return false;
     return bool(testKind & transformKind);
-#else
-    return true;
-#endif
   }
 
   void reset() {
diff --git a/lib/SILOptimizer/SemanticARC/CopyValueOpts.cpp b/lib/SILOptimizer/SemanticARC/CopyValueOpts.cpp
index e11eb9452996a..0df7f3d65af4a 100644
--- a/lib/SILOptimizer/SemanticARC/CopyValueOpts.cpp
+++ b/lib/SILOptimizer/SemanticARC/CopyValueOpts.cpp
@@ -14,7 +14,7 @@
 ///
 /// Contains optimizations that eliminate redundant copy values.
 ///
-/// FIXME: CanonicalizeOSSALifetime likely replaces everything this file.
+/// FIXME: OSSACanonicalizeOwned likely replaces everything this file.
 ///
 //===----------------------------------------------------------------------===//
 
@@ -27,6 +27,7 @@
 #include "swift/SIL/MemAccessUtils.h"
 #include "swift/SIL/OwnershipUtils.h"
 #include "swift/SIL/Projection.h"
+#include "swift/SIL/Test.h"
 
 using namespace swift;
 using namespace swift::semanticarc;
@@ -72,7 +73,7 @@ bool SemanticARCOptVisitor::performGuaranteedCopyValueOptimization(
   LLVM_DEBUG(llvm::dbgs() << "Looking at ");
   LLVM_DEBUG(cvi->dump());
 
-  // All mandatory copy optimization is handled by CanonicalizeOSSALifetime,
+  // All mandatory copy optimization is handled by OSSACanonicalizeOwned,
   // which knows how to preserve lifetimes for debugging.
   if (ctx.onlyMandatoryOpts)
     return false;
@@ -170,7 +171,7 @@ bool SemanticARCOptVisitor::performGuaranteedCopyValueOptimization(
         return borrowScope.isLocalScope();
       });
 
-  auto destroys = lr.getDestroyingUses();
+  auto destroys = lr.getDestroyingInsts();
   if (destroys.empty() && haveAnyLocalScopes) {
     return false;
   }
@@ -196,8 +197,8 @@ bool SemanticARCOptVisitor::performGuaranteedCopyValueOptimization(
   // block.
   {
     if (llvm::any_of(borrowScopeIntroducers, [&](BorrowedValue borrowScope) {
-          return !borrowScope.areUsesWithinExtendedScope(
-              lr.getAllConsumingUses(), nullptr);
+          return !borrowScope.areWithinExtendedScope(lr.getAllConsumingInsts(),
+                                                     nullptr);
         })) {
       LLVM_DEBUG(llvm::dbgs() << "copy_value is extending borrow introducer "
                                  "lifetime, bailing out\n");
@@ -238,8 +239,8 @@ bool SemanticARCOptVisitor::performGuaranteedCopyValueOptimization(
       }
 
       if (llvm::any_of(borrowScopeIntroducers, [&](BorrowedValue borrowScope) {
-            return !borrowScope.areUsesWithinExtendedScope(
-                phiArgLR.getAllConsumingUses(), nullptr);
+            return !borrowScope.areWithinExtendedScope(
+                phiArgLR.getAllConsumingInsts(), nullptr);
           })) {
         return false;
       }
@@ -272,7 +273,7 @@ bool SemanticARCOptVisitor::performGuaranteedCopyValueOptimization(
 /// If cvi only has destroy value users, then cvi is a dead live range. Lets
 /// eliminate all such dead live ranges.
 ///
-/// FIXME: CanonicalizeOSSALifetime replaces this.
+/// FIXME: OSSACanonicalizeOwned replaces this.
 bool SemanticARCOptVisitor::eliminateDeadLiveRangeCopyValue(
     CopyValueInst *cvi) {
   // This is a cheap optimization generally.
@@ -503,6 +504,13 @@ static bool tryJoinIfDestroyConsumingUseInSameBlock(
     if (visitedInsts.count(use->getUser()))
       return false;
 
+    // If the cvi's operand value has a non-consuming use in the same
+    // instruction which consumes the copy, bailout. NOTE:
+    // isUseBetweenInstAndBlockEnd does not check this.
+    if (user == singleCVIConsumingUse->getUser()) {
+      return false;
+    }
+
     // Ok, we have a use that isn't in our visitedInsts region. That being said,
     // we may still have a use that introduces a new BorrowScope onto our
     // copy_value's operand that overlaps with our forwarding value region. In
@@ -513,7 +521,7 @@ static bool tryJoinIfDestroyConsumingUseInSameBlock(
     // we need to only find scopes that end within the region in between the
     // singleConsumingUse (the original forwarded use) and the destroy_value. In
     // such a case, we must bail!
-    if (auto operand = BorrowingOperand(use))
+    if (auto operand = BorrowingOperand(use)) {
       if (!operand.visitScopeEndingUses([&](Operand *endScopeUse) {
             // Return false if we did see the relevant end scope instruction
             // in the block. That means that we are going to exit early and
@@ -521,6 +529,7 @@ static bool tryJoinIfDestroyConsumingUseInSameBlock(
             return !visitedInsts.count(endScopeUse->getUser());
           }))
         return false;
+    }
   }
 
   // Ok, we now know that we can eliminate this value.
@@ -656,7 +665,7 @@ static bool tryJoiningIfCopyOperandHasSingleDestroyValue(
 // begin_borrow. Because of that we can not shrink lifetimes and instead rely on
 // SILGen's correctness.
 //
-// FIXME: CanonicalizeOSSALifetime replaces this.
+// FIXME: OSSACanonicalizeOwned replaces this.
 bool SemanticARCOptVisitor::tryJoiningCopyValueLiveRangeWithOperand(
     CopyValueInst *cvi) {
   // First do a quick check if our operand is owned. If it is not owned, we can
@@ -762,7 +771,7 @@ bool SemanticARCOptVisitor::tryJoiningCopyValueLiveRangeWithOperand(
 /// value and is not consumed, eliminate the copy.
 bool SemanticARCOptVisitor::tryPerformOwnedCopyValueOptimization(
     CopyValueInst *cvi) {
-  // All mandatory copy optimization is handled by CanonicalizeOSSALifetime,
+  // All mandatory copy optimization is handled by OSSACanonicalizeOwned,
   // which knows how to preserve lifetimes for debugging.
   if (ctx.onlyMandatoryOpts)
     return false;
@@ -805,7 +814,9 @@ bool SemanticARCOptVisitor::tryPerformOwnedCopyValueOptimization(
   // Ok, we have an owned value. If we do not have any non-destroying consuming
   // uses, see if all of our uses (ignoring destroying uses) are within our
   // parent owned value's lifetime.
-  LinearLifetimeChecker checker(&ctx.getDeadEndBlocks());
+  // Note: we cannot optimistically ignore DeadEndBlocks - unlike for ownership
+  //       verification.
+  LinearLifetimeChecker checker(nullptr);
   if (!checker.validateLifetime(originalValue, parentLifetimeEndingUses,
                                 allCopyUses))
     return false;
@@ -818,6 +829,20 @@ bool SemanticARCOptVisitor::tryPerformOwnedCopyValueOptimization(
   return true;
 }
 
+namespace swift::test {
+static FunctionTest SemanticARCOptsCopyValueOptsGuaranteedValueOptTest(
+    "semantic_arc_opts__copy_value_opts__guaranteed_value_opt",
+    [](auto &function, auto &arguments, auto &test) {
+      SemanticARCOptVisitor visitor(function, test.getPassManager(),
+                                    *test.getDeadEndBlocks(),
+                                    /*onlyMandatoryOpts=*/false);
+
+      visitor.performGuaranteedCopyValueOptimization(
+          cast<CopyValueInst>(arguments.takeInstruction()));
+      function.print(llvm::errs());
+    });
+} // end namespace swift::test
+
 //===----------------------------------------------------------------------===//
 //                            Top Level Entrypoint
 //===----------------------------------------------------------------------===//
diff --git a/lib/SILOptimizer/SemanticARC/OwnedToGuaranteedPhiOpt.cpp b/lib/SILOptimizer/SemanticARC/OwnedToGuaranteedPhiOpt.cpp
index 51f065dd3f748..321558adec205 100644
--- a/lib/SILOptimizer/SemanticARC/OwnedToGuaranteedPhiOpt.cpp
+++ b/lib/SILOptimizer/SemanticARC/OwnedToGuaranteedPhiOpt.cpp
@@ -175,11 +175,11 @@ bool swift::semanticarc::tryConvertOwnedPhisToGuaranteedPhis(Context &ctx) {
       std::function<Operand *(const Context::ConsumingOperandState)> lambda =
         [&](const Context::ConsumingOperandState &state) -> Operand * {
             unsigned opNum = state.operandNumber;
-            if (state.parent.is<SILBasicBlock *>()) {
-              SILBasicBlock *block = state.parent.get<SILBasicBlock *>();
+            if (isa<SILBasicBlock *>(state.parent)) {
+              SILBasicBlock *block = cast<SILBasicBlock *>(state.parent);
               return &block->getTerminator()->getAllOperands()[opNum];
             }
-            SILInstruction *inst = state.parent.get<SILInstruction *>();
+            SILInstruction *inst = cast<SILInstruction *>(state.parent);
             return &inst->getAllOperands()[opNum];
         };
       auto operandsTransformed = makeTransformRange(pair.second, lambda);
@@ -212,7 +212,11 @@ bool swift::semanticarc::tryConvertOwnedPhisToGuaranteedPhis(Context &ctx) {
     SmallVector<std::pair<SILValue, unsigned>, 8> incomingValueUpdates;
     for (auto introducer : ownedValueIntroducers) {
       SILValue v = introducer.value;
-      OwnershipLiveRange lr(v);
+      SmallVector<std::pair<Operand *, SILValue>, 4> extraConsumes;
+      for (auto op : incomingValueOperandList) {
+        extraConsumes.push_back({op.getOperand(), op.getOriginal()});
+      }
+      OwnershipLiveRange lr(v, extraConsumes);
 
       // For now, we only handle copy_value for simplicity.
       //
diff --git a/lib/SILOptimizer/SemanticARC/OwnershipLiveRange.cpp b/lib/SILOptimizer/SemanticARC/OwnershipLiveRange.cpp
index 63acb4ad28d3b..33b68d5db0d09 100644
--- a/lib/SILOptimizer/SemanticARC/OwnershipLiveRange.cpp
+++ b/lib/SILOptimizer/SemanticARC/OwnershipLiveRange.cpp
@@ -15,20 +15,25 @@
 
 #include "swift/Basic/Assertions.h"
 #include "swift/SIL/BasicBlockUtils.h"
+#include "swift/SIL/OSSACompleteLifetime.h"
 #include "swift/SIL/OwnershipUtils.h"
 
 using namespace swift;
 using namespace swift::semanticarc;
 
-OwnershipLiveRange::OwnershipLiveRange(SILValue value)
+OwnershipLiveRange::OwnershipLiveRange(
+    SILValue value, ArrayRef<std::pair<Operand *, SILValue>> extraUses)
     : introducer(OwnedValueIntroducer::get(value)), destroyingUses(),
       ownershipForwardingUses(), unknownConsumingUses() {
   assert(introducer);
   assert(introducer.value->getOwnershipKind() == OwnershipKind::Owned);
 
-  SmallVector<Operand *, 32> tmpDestroyingUses;
-  SmallVector<Operand *, 32> tmpForwardingConsumingUses;
-  SmallVector<Operand *, 32> tmpUnknownConsumingUses;
+  SmallVector<UsePoint, 32> tmpDestroyingUses;
+  SmallVector<UsePoint, 32> tmpForwardingConsumingUses;
+  SmallVector<UsePoint, 32> tmpUnknownConsumingUses;
+
+  SmallVector<SILValue, 4> defs;
+  defs.push_back(value);
 
   // We know that our silvalue produces an @owned value. Look through all of our
   // uses and classify them as either consuming or not.
@@ -111,6 +116,7 @@ OwnershipLiveRange::OwnershipLiveRange(SILValue value)
           continue;
         }
         llvm::copy(v->getUses(), std::back_inserter(worklist));
+        defs.push_back(v);
       }
       continue;
     }
@@ -138,8 +144,32 @@ OwnershipLiveRange::OwnershipLiveRange(SILValue value)
         // Otherwise add all users of this BBArg to the worklist to visit
         // recursively.
         llvm::copy(succArg->getUses(), std::back_inserter(worklist));
+        defs.push_back(succArg);
+      }
+    }
+  }
+
+  for (auto def : defs) {
+    if (def->use_begin() == def->use_end()) {
+      continue;
+    }
+    SmallVector<SILBasicBlock *, 32> blocks;
+    SSAPrunedLiveness liveness(def->getFunction(), &blocks);
+    liveness.initializeDef(def);
+    liveness.computeSimple();
+    for (auto use : extraUses) {
+      if (use.second != def) {
+        continue;
       }
+      liveness.updateForUse(use.first->getUser(), /*lifetimeEnding=*/true);
     }
+    OSSACompleteLifetime::visitAvailabilityBoundary(
+        def, liveness, [&tmpDestroyingUses](auto *inst, auto end) {
+          if (end != OSSACompleteLifetime::LifetimeEnd::Boundary) {
+            return;
+          }
+          tmpDestroyingUses.push_back(inst);
+        });
   }
 
   // The order in which we append these to consumingUses matters since we assume
@@ -248,7 +278,8 @@ void OwnershipLiveRange::insertEndBorrowsAtDestroys(
 
 void OwnershipLiveRange::convertOwnedGeneralForwardingUsesToGuaranteed() && {
   while (!ownershipForwardingUses.empty()) {
-    auto *use = ownershipForwardingUses.back();
+    auto point = ownershipForwardingUses.back();
+    auto *use = point.getOperand();
     ownershipForwardingUses = ownershipForwardingUses.drop_back();
     ForwardingOperand operand(use);
     operand.replaceOwnershipKind(OwnershipKind::Owned,
@@ -260,9 +291,12 @@ void OwnershipLiveRange::convertToGuaranteedAndRAUW(
     SILValue newGuaranteedValue, InstModCallbacks callbacks) && {
   auto *value = cast<SingleValueInstruction>(introducer.value);
   while (!destroyingUses.empty()) {
-    auto *d = destroyingUses.back();
+    auto point = destroyingUses.back();
+    auto *destroy = point.getInstruction();
     destroyingUses = destroyingUses.drop_back();
-    callbacks.deleteInst(d->getUser());
+    if (isa<TermInst>(destroy))
+      continue;
+    callbacks.deleteInst(destroy);
   }
 
   callbacks.eraseAndRAUWSingleValueInst(value, newGuaranteedValue);
@@ -318,9 +352,12 @@ void OwnershipLiveRange::convertJoinedLiveRangePhiToGuaranteed(
 
   // Then eliminate all of the destroys...
   while (!destroyingUses.empty()) {
-    auto *d = destroyingUses.back();
+    auto point = destroyingUses.back();
+    auto *destroy = point.getInstruction();
     destroyingUses = destroyingUses.drop_back();
-    callbacks.deleteInst(d->getUser());
+    if (isa<TermInst>(destroy))
+      continue;
+    callbacks.deleteInst(destroy);
   }
 
   // and change all of our guaranteed forwarding insts to have guaranteed
@@ -362,13 +399,3 @@ OwnershipLiveRange::hasUnknownConsumingUse(bool assumingAtFixPoint) const {
   // to our introducer.
   return HasConsumingUse_t::YesButAllPhiArgs;
 }
-
-OwnershipLiveRange::DestroyingInstsRange
-OwnershipLiveRange::getDestroyingInsts() const {
-  return DestroyingInstsRange(getDestroyingUses(), OperandToUser());
-}
-
-OwnershipLiveRange::ConsumingInstsRange
-OwnershipLiveRange::getAllConsumingInsts() const {
-  return ConsumingInstsRange(consumingUses, OperandToUser());
-}
diff --git a/lib/SILOptimizer/SemanticARC/OwnershipLiveRange.h b/lib/SILOptimizer/SemanticARC/OwnershipLiveRange.h
index 225f9398f1d8e..b5ec7366abb85 100644
--- a/lib/SILOptimizer/SemanticARC/OwnershipLiveRange.h
+++ b/lib/SILOptimizer/SemanticARC/OwnershipLiveRange.h
@@ -54,12 +54,18 @@ class LLVM_LIBRARY_VISIBILITY OwnershipLiveRange {
   /// order. This is why it is important not to mutate consumingUses after we
   /// construct the LiveRange since going from small -> large could invalidate
   /// the uses.
-  SmallVector<Operand *, 6> consumingUses;
+  ///
+  /// These UsePoints may be Operands or SILInstructions (terminators of blocks
+  /// in dead-end regions along the value's availability boundary).
+  SmallVector<UsePoint, 6> consumingUses;
 
   /// A list of destroy_values of the live range.
   ///
-  /// This is just a view into consuming uses.
-  ArrayRef<Operand *> destroyingUses;
+  /// This is just a view into consumingUses.
+  ///
+  /// These UsePoints may be Operands or SILInstructions (terminators of blocks
+  /// in dead-end regions along the value's availability boundary).
+  ArrayRef<UsePoint> destroyingUses;
 
   /// A list of forwarding instructions that forward owned ownership, but that
   /// are also able to be converted to guaranteed ownership.
@@ -76,15 +82,20 @@ class LLVM_LIBRARY_VISIBILITY OwnershipLiveRange {
   /// "consumingUses" array the true lifetime of the OwnershipLiveRange.
   ///
   /// Corresponds to isOwnershipForwardingInst(...).
-  ArrayRef<Operand *> ownershipForwardingUses;
+  ///
+  /// These UsePoints must all be Operands.
+  ArrayRef<UsePoint> ownershipForwardingUses;
 
   /// Consuming uses that we were not able to understand as a forwarding
   /// instruction or a destroy_value. These must be passed a strongly control
   /// equivalent +1 value.
-  ArrayRef<Operand *> unknownConsumingUses;
+  ///
+  /// These UsePoints must all be Operands.
+  ArrayRef<UsePoint> unknownConsumingUses;
 
 public:
-  OwnershipLiveRange(SILValue value);
+  OwnershipLiveRange(SILValue value,
+                     ArrayRef<std::pair<Operand *, SILValue>> extraUses = {});
   OwnershipLiveRange(const OwnershipLiveRange &) = delete;
   OwnershipLiveRange &operator=(const OwnershipLiveRange &) = delete;
 
@@ -102,36 +113,17 @@ class LLVM_LIBRARY_VISIBILITY OwnershipLiveRange {
   HasConsumingUse_t
   hasUnknownConsumingUse(bool assumingFixedPoint = false) const;
 
-  /// Return an array ref to /all/ consuming uses. Will include all 3 sorts of
-  /// consuming uses: destroying uses, forwarding consuming uses, and unknown
-  /// forwarding instruction.
-  ArrayRef<Operand *> getAllConsumingUses() const { return consumingUses; }
-
-  ArrayRef<Operand *> getDestroyingUses() const { return destroyingUses; }
-
-  ArrayRef<Operand *> getUnknownConsumingUses() const {
-    return unknownConsumingUses;
+  UsePointInstructionRange getDestroyingInsts() const {
+    return UsePointInstructionRange(destroyingUses, UsePointToInstruction());
   }
 
-private:
-  struct OperandToUser;
+  UsePointInstructionRange getUnknownConsumingInsts() const {
+    return UsePointInstructionRange(unknownConsumingUses,
+                                    UsePointToInstruction());
+  }
 
-public:
-  using DestroyingInstsRange =
-      TransformRange<ArrayRef<Operand *>, OperandToUser>;
-  DestroyingInstsRange getDestroyingInsts() const;
-
-  using ConsumingInstsRange =
-      TransformRange<ArrayRef<Operand *>, OperandToUser>;
-  ConsumingInstsRange getAllConsumingInsts() const;
-
-  /// If this LiveRange has a single destroying use, return that use. Otherwise,
-  /// return nullptr.
-  Operand *getSingleDestroyingUse() const {
-    if (destroyingUses.size() != 1) {
-      return nullptr;
-    }
-    return destroyingUses.front();
+  UsePointInstructionRange getAllConsumingInsts() const {
+    return UsePointInstructionRange(consumingUses, UsePointToInstruction());
   }
 
   /// If this LiveRange has a single unknown destroying use, return that
@@ -140,13 +132,14 @@ class LLVM_LIBRARY_VISIBILITY OwnershipLiveRange {
     if (unknownConsumingUses.size() != 1) {
       return nullptr;
     }
-    return unknownConsumingUses.front();
+    auto point = unknownConsumingUses.front();
+    return point.getOperand();
   }
 
   OwnedValueIntroducer getIntroducer() const { return introducer; }
 
-  ArrayRef<Operand *> getOwnershipForwardingUses() const {
-    return ownershipForwardingUses;
+  PointOperandRange getOwnershipForwardingUses() const {
+    return PointOperandRange(ownershipForwardingUses, PointToOperand());
   }
 
   void convertOwnedGeneralForwardingUsesToGuaranteed() &&;
@@ -198,16 +191,6 @@ class LLVM_LIBRARY_VISIBILITY OwnershipLiveRange {
                                   DeadEndBlocks &deadEndBlocks,
                                   ValueLifetimeAnalysis::Frontier &scratch);
 };
-
-struct OwnershipLiveRange::OperandToUser {
-  OperandToUser() {}
-
-  SILInstruction *operator()(const Operand *use) const {
-    auto *nonConstUse = const_cast<Operand *>(use);
-    return nonConstUse->getUser();
-  }
-};
-
 } // namespace semanticarc
 } // namespace swift
 
diff --git a/lib/SILOptimizer/SemanticARC/OwnershipPhiOperand.h b/lib/SILOptimizer/SemanticARC/OwnershipPhiOperand.h
index 33b211ccc91b5..a737bee9f18dd 100644
--- a/lib/SILOptimizer/SemanticARC/OwnershipPhiOperand.h
+++ b/lib/SILOptimizer/SemanticARC/OwnershipPhiOperand.h
@@ -36,6 +36,7 @@ class LLVM_LIBRARY_VISIBILITY OwnershipPhiOperand {
 
 private:
   Operand *op;
+  SILValue original;
 
   OwnershipPhiOperand(Operand *op) : op(op) {}
 
@@ -70,10 +71,14 @@ class LLVM_LIBRARY_VISIBILITY OwnershipPhiOperand {
   Operand *getOperand() const { return op; }
   SILValue getValue() const { return op->get(); }
   SILType getType() const { return op->get()->getType(); }
+  SILValue getOriginal() const { return original; }
 
   unsigned getOperandNumber() const { return op->getOperandNumber(); }
 
-  void markUndef() & { op->set(SILUndef::get(getValue())); }
+  void markUndef() & {
+    original = op->get();
+    op->set(SILUndef::get(getValue()));
+  }
 
   SILInstruction *getInst() const { return op->getUser(); }
 
diff --git a/lib/SILOptimizer/SemanticARC/SemanticARCOpts.cpp b/lib/SILOptimizer/SemanticARC/SemanticARCOpts.cpp
index 67d3230709eb3..0bc29ade245a3 100644
--- a/lib/SILOptimizer/SemanticARC/SemanticARCOpts.cpp
+++ b/lib/SILOptimizer/SemanticARC/SemanticARCOpts.cpp
@@ -77,7 +77,6 @@ struct SemanticARCOpts : SILFunctionTransform {
   SemanticARCOpts(bool mandatoryOptsOnly)
       : mandatoryOptsOnly(mandatoryOptsOnly) {}
 
-#ifndef NDEBUG
   void performCommandlineSpecifiedTransforms(SemanticARCOptVisitor &visitor) {
     for (auto transform : TransformsToPerform) {
       visitor.ctx.transformKind = transform;
@@ -110,7 +109,6 @@ struct SemanticARCOpts : SILFunctionTransform {
       }
     }
   }
-#endif
 
   bool performPeepholesWithoutFixedPoint(SemanticARCOptVisitor &visitor) {
     // Add all the results of all instructions that we want to visit to the
@@ -162,13 +160,11 @@ struct SemanticARCOpts : SILFunctionTransform {
     SemanticARCOptVisitor visitor(f, getPassManager(), *deBlocksAnalysis->get(&f),
                                   mandatoryOptsOnly);
 
-#ifndef NDEBUG
     // If we are being asked for testing purposes to run a series of transforms
     // expressed on the command line, run that and return.
     if (!TransformsToPerform.empty()) {
       return performCommandlineSpecifiedTransforms(visitor);
     }
-#endif
 
     // Otherwise, perform our standard optimizations.
     bool didEliminateARCInsts = performPeepholes(visitor);
diff --git a/lib/SILOptimizer/Transforms/ARCCodeMotion.cpp b/lib/SILOptimizer/Transforms/ARCCodeMotion.cpp
index 58d4769043585..7b310f5115541 100644
--- a/lib/SILOptimizer/Transforms/ARCCodeMotion.cpp
+++ b/lib/SILOptimizer/Transforms/ARCCodeMotion.cpp
@@ -433,9 +433,12 @@ void RetainCodeMotionContext::initializeCodeMotionDataFlow() {
         continue;
       if (!parentTransform->continueWithNextSubpassRun(&II))
         continue;
+      SILValue Root = getRCRoot(&II);
+      if (Root->getType().isMoveOnly()) {
+        continue;
+      }
       retainInstructions.insert(&II);
       RCInstructions.insert(&II);
-      SILValue Root = getRCRoot(&II);
       if (RCRootIndex.find(Root) != RCRootIndex.end())
         continue;
       RCRootIndex[Root] = RCRootVault.size();
@@ -818,8 +821,11 @@ void ReleaseCodeMotionContext::initializeCodeMotionDataFlow() {
         continue;
       if (!parentTransform->continueWithNextSubpassRun(&II))
         continue;
-      releaseInstructions.insert(&II);
       SILValue Root = getRCRoot(&II);
+      if (Root->getType().isMoveOnly()) {
+        continue;
+      }
+      releaseInstructions.insert(&II);
       RCInstructions.insert(&II);
       if (RCRootIndex.find(Root) != RCRootIndex.end())
         continue;
diff --git a/lib/SILOptimizer/Transforms/AccessEnforcementReleaseSinking.cpp b/lib/SILOptimizer/Transforms/AccessEnforcementReleaseSinking.cpp
index fa157170489da..3981e2928d980 100644
--- a/lib/SILOptimizer/Transforms/AccessEnforcementReleaseSinking.cpp
+++ b/lib/SILOptimizer/Transforms/AccessEnforcementReleaseSinking.cpp
@@ -121,7 +121,10 @@ static bool isBarrier(SILInstruction *inst) {
     case BuiltinValueKind::OnFastPath:
     case BuiltinValueKind::ExtractElement:
     case BuiltinValueKind::InsertElement:
+    case BuiltinValueKind::Select:
     case BuiltinValueKind::ShuffleVector:
+    case BuiltinValueKind::Interleave:
+    case BuiltinValueKind::Deinterleave:
     case BuiltinValueKind::StaticReport:
     case BuiltinValueKind::AssertConf:
     case BuiltinValueKind::StringObjectOr:
@@ -134,6 +137,7 @@ static bool isBarrier(SILInstruction *inst) {
     case BuiltinValueKind::IsNegative:
     case BuiltinValueKind::WordAtIndex:
     case BuiltinValueKind::ZeroInitializer:
+    case BuiltinValueKind::PrepareInitialization:
     case BuiltinValueKind::Once:
     case BuiltinValueKind::OnceWithContext:
     case BuiltinValueKind::GetObjCTypeEncoding:
diff --git a/lib/SILOptimizer/Transforms/AccessEnforcementWMO.cpp b/lib/SILOptimizer/Transforms/AccessEnforcementWMO.cpp
index 1ae61d99d7f53..71ee75764a760 100644
--- a/lib/SILOptimizer/Transforms/AccessEnforcementWMO.cpp
+++ b/lib/SILOptimizer/Transforms/AccessEnforcementWMO.cpp
@@ -107,7 +107,7 @@ static bool isVisibleExternally(DisjointAccessLocationKey key, SILModule *mod) {
   if (auto *decl = key.dyn_cast<const VarDecl *>())
     return mod->isVisibleExternally(decl);
 
-  auto *global = key.get<const SILGlobalVariable *>();
+  auto *global = cast<const SILGlobalVariable *>(key);
   return isPossiblyUsedExternally(global->getLinkage(), mod->isWholeModule());
 }
 
@@ -115,7 +115,7 @@ static StringRef getName(DisjointAccessLocationKey key) {
   if (auto *decl = key.dyn_cast<const VarDecl *>())
     return decl->getNameStr();
 
-  return key.get<const SILGlobalVariable *>()->getName();
+  return cast<const SILGlobalVariable *>(key)->getName();
 }
 
 namespace {
diff --git a/lib/SILOptimizer/Transforms/AllocBoxToStack.cpp b/lib/SILOptimizer/Transforms/AllocBoxToStack.cpp
index ae08e252c3104..e4bf5db46a804 100644
--- a/lib/SILOptimizer/Transforms/AllocBoxToStack.cpp
+++ b/lib/SILOptimizer/Transforms/AllocBoxToStack.cpp
@@ -25,6 +25,8 @@
 #include "swift/SIL/SILArgument.h"
 #include "swift/SIL/SILBuilder.h"
 #include "swift/SIL/SILCloner.h"
+#include "swift/SILOptimizer/Analysis/DeadEndBlocksAnalysis.h"
+#include "swift/SILOptimizer/Analysis/LoopAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Passes.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/InstOptUtils.h"
@@ -355,7 +357,8 @@ static bool isOptimizableApplySite(ApplySite Apply) {
     return false;
 
   // Do not optimize always_inlinable functions.
-  if (callee->getInlineStrategy() == Inline_t::AlwaysInline)
+  if (callee->getInlineStrategy() == Inline_t::HeuristicAlwaysInline ||
+      callee->getInlineStrategy() == Inline_t::AlwaysInline)
     return false;
 
   if (callee->getLinkage() != SILLinkage::Private)
@@ -601,7 +604,9 @@ static void hoistMarkUnresolvedNonCopyableValueInsts(
 
 /// rewriteAllocBoxAsAllocStack - Replace uses of the alloc_box with a
 /// new alloc_stack, but do not delete the alloc_box yet.
-static bool rewriteAllocBoxAsAllocStack(AllocBoxInst *ABI) {
+static bool rewriteAllocBoxAsAllocStack(AllocBoxInst *ABI,
+                                        DeadEndBlocksAnalysis &deba,
+                                        SILLoopAnalysis &la) {
   LLVM_DEBUG(llvm::dbgs() << "*** Promoting alloc_box to stack: " << *ABI);
 
   SILValue HeapBox = ABI;
@@ -693,9 +698,31 @@ static bool rewriteAllocBoxAsAllocStack(AllocBoxInst *ABI) {
                          ABI->getBoxType(), ABI->getModule().Types, 0));
   auto Loc = CleanupLocation(ABI->getLoc());
 
+  auto *deb = deba.get(ABI->getFunction());
   for (auto LastRelease : FinalReleases) {
+    auto *dbi = dyn_cast<DeallocBoxInst>(LastRelease);
+    if (!dbi && deb->isDeadEnd(LastRelease->getParent()) &&
+        !la.get(ABI->getFunction())->getLoopFor(LastRelease->getParent())) {
+      // "Last" releases in dead-end regions may not actually destroy the box
+      // and consequently may not actually release the stored value.  That's
+      // because values (including boxes) may be leaked along paths into
+      // dead-end regions.  Thus it is invalid to lower such final releases of
+      // the box to destroy_addr's/dealloc_box's of the stack-promoted storage.
+      //
+      // There is one exception: if the alloc_box is in a dead-end loop.  In
+      // that case SIL invariants require that the final releases actually
+      // destroy the box; otherwise, a box would leak once per loop.  To check
+      // for this, it is sufficient check that the LastRelease is in a dead-end
+      // loop: if the alloc_box is not in that loop, then the entire loop is in
+      // the live range, so no release within the loop would be a "final
+      // release".
+      //
+      // None of this applies to dealloc_box instructions which always destroy
+      // the box.
+      continue;
+    }
     SILBuilderWithScope Builder(LastRelease);
-    if (!isa<DeallocBoxInst>(LastRelease)&& !Lowering.isTrivial()) {
+    if (!dbi && !Lowering.isTrivial()) {
       // If we have a mark_unresolved_non_copyable_value use of our stack box,
       // we want to destroy that.
       SILValue valueToDestroy = StackBox;
@@ -709,7 +736,6 @@ static bool rewriteAllocBoxAsAllocStack(AllocBoxInst *ABI) {
       // instruction we found that isn't an explicit dealloc_box.
       Builder.emitDestroyAddrAndFold(Loc, valueToDestroy);
     }
-    auto *dbi = dyn_cast<DeallocBoxInst>(LastRelease);
     if (dbi && dbi->isDeadEnd()) {
       // Don't bother to create dealloc_stack instructions in dead-ends.
       continue;
@@ -1265,7 +1291,9 @@ static void rewriteApplySites(AllocBoxToStackState &pass) {
 
 /// Clone closure bodies and rewrite partial applies. Returns the number of
 /// alloc_box allocations promoted.
-static unsigned rewritePromotedBoxes(AllocBoxToStackState &pass) {
+static unsigned rewritePromotedBoxes(AllocBoxToStackState &pass,
+                                     DeadEndBlocksAnalysis &deba,
+                                     SILLoopAnalysis &la) {
   // First we'll rewrite any ApplySite that we can to remove
   // the box container pointer from the operands.
   rewriteApplySites(pass);
@@ -1274,7 +1302,7 @@ static unsigned rewritePromotedBoxes(AllocBoxToStackState &pass) {
   auto rend = pass.Promotable.rend();
   for (auto I = pass.Promotable.rbegin(); I != rend; ++I) {
     auto *ABI = *I;
-    if (rewriteAllocBoxAsAllocStack(ABI)) {
+    if (rewriteAllocBoxAsAllocStack(ABI, deba, la)) {
       ++Count;
       ABI->eraseFromParent();
     }
@@ -1299,7 +1327,9 @@ class AllocBoxToStack : public SILFunctionTransform {
     }
 
     if (!pass.Promotable.empty()) {
-      auto Count = rewritePromotedBoxes(pass);
+      auto *deba = getAnalysis<DeadEndBlocksAnalysis>();
+      auto *la = getAnalysis<SILLoopAnalysis>();
+      auto Count = rewritePromotedBoxes(pass, *deba, *la);
       NumStackPromoted += Count;
       if (Count) {
         if (StackNesting::fixNesting(getFunction()) == StackNesting::Changes::CFG)
@@ -1315,6 +1345,6 @@ class AllocBoxToStack : public SILFunctionTransform {
 };
 } // end anonymous namespace
 
-SILTransform *swift::createAllocBoxToStack() {
+SILTransform *swift::createLegacyAllocBoxToStack() {
   return new AllocBoxToStack();
 }
diff --git a/lib/SILOptimizer/Transforms/CMakeLists.txt b/lib/SILOptimizer/Transforms/CMakeLists.txt
index e2887f039b26a..9728f59996728 100644
--- a/lib/SILOptimizer/Transforms/CMakeLists.txt
+++ b/lib/SILOptimizer/Transforms/CMakeLists.txt
@@ -32,7 +32,5 @@ target_sources(swiftSILOptimizer PRIVATE
   SimplifyCFG.cpp
   Sink.cpp
   SpeculativeDevirtualizer.cpp
-  StringOptimization.cpp
-  TempLValueOpt.cpp
-  TempRValueElimination.cpp)
+  StringOptimization.cpp)
 
diff --git a/lib/SILOptimizer/Transforms/CSE.cpp b/lib/SILOptimizer/Transforms/CSE.cpp
index 4de4eeac6423b..2139509343826 100644
--- a/lib/SILOptimizer/Transforms/CSE.cpp
+++ b/lib/SILOptimizer/Transforms/CSE.cpp
@@ -520,10 +520,7 @@ class HashVisitor : public SILInstructionVisitor<HashVisitor, llvm::hash_code> {
   }
 
   hash_code visitTypeValueInst(TypeValueInst *X) {
-    OperandValueArrayRef Operands(X->getAllOperands());
-    return llvm::hash_combine(
-        X->getKind(), X->getType(),
-        llvm::hash_combine_range(Operands.begin(), Operands.end()));
+    return llvm::hash_combine(X->getKind(), X->getType(), X->getParamType());
   }
 };
 } // end anonymous namespace
@@ -568,6 +565,13 @@ bool llvm::DenseMapInfo<SimpleValue>::isEqual(SimpleValue LHS,
 
     return true;
   }
+  auto *ltvi = dyn_cast<TypeValueInst>(LHSI);
+  auto *rtvi = dyn_cast<TypeValueInst>(RHSI);
+  if (ltvi && rtvi) {
+    if (ltvi->getType() != rtvi->getType())
+      return false;
+    return ltvi->getParamType() == rtvi->getParamType();
+  }
   auto opCmp = [&](const Operand *op1, const Operand *op2) -> bool {
     if (op1 == op2)
       return true;
@@ -839,8 +843,7 @@ bool CSE::processLazyPropertyGetters(SILFunction &F) {
 /// archetypes. Replace such types by performing type substitutions
 /// according to the provided type substitution map.
 static void updateBasicBlockArgTypes(SILBasicBlock *BB,
-                                     ArchetypeType *OldOpenedArchetype,
-                                     ArchetypeType *NewOpenedArchetype,
+                                     InstructionCloner &Cloner,
                                      InstructionWorklist &usersToHandle) {
   // Check types of all BB arguments.
   for (auto *Arg : BB->getSILPhiArguments()) {
@@ -850,15 +853,8 @@ static void updateBasicBlockArgTypes(SILBasicBlock *BB,
     // Try to apply substitutions to it and if it produces a different type,
     // use this type as new type of the BB argument.
     auto OldArgType = Arg->getType();
-    auto NewArgType = OldArgType.subst(BB->getModule(),
-                                       [&](SubstitutableType *type) -> Type {
-                                         if (type == OldOpenedArchetype)
-                                           return NewOpenedArchetype;
-                                         return type;
-                                       },
-                                       MakeAbstractConformanceForGenericType(),
-                                       CanGenericSignature(),
-                                       SubstFlags::SubstituteLocalArchetypes);
+
+    auto NewArgType = Cloner.getOpType(OldArgType);
     if (NewArgType == Arg->getType())
       continue;
     // Replace the type of this BB argument. The type of a BBArg
@@ -910,13 +906,14 @@ bool CSE::processOpenExistentialRef(OpenExistentialRefInst *Inst,
     usersToHandle.pushIfNotVisited(User);
   }
 
+  auto *OldEnv = OldOpenedArchetype->getGenericEnvironment();
+  auto *NewEnv = NewOpenedArchetype->getGenericEnvironment();
+
   // Now process candidates.
   // Use a cloner. It makes copying the instruction and remapping of
   // opened archetypes trivial.
   InstructionCloner Cloner(Inst->getFunction());
-  Cloner.registerLocalArchetypeRemapping(
-      OldOpenedArchetype->getGenericEnvironment(),
-      NewOpenedArchetype->getGenericEnvironment());
+  Cloner.registerLocalArchetypeRemapping(OldEnv, NewEnv);
   auto &Builder = Cloner.getBuilder();
 
   // Now clone each candidate and replace the opened archetype
@@ -931,8 +928,7 @@ bool CSE::processOpenExistentialRef(OpenExistentialRefInst *Inst,
         if (Successor->args_empty())
           continue;
         // If a BB has any arguments, update their types if necessary.
-        updateBasicBlockArgTypes(Successor, OldOpenedArchetype,
-                                 NewOpenedArchetype, usersToHandle);
+        updateBasicBlockArgTypes(Successor, Cloner, usersToHandle);
       }
     }
 
@@ -948,10 +944,7 @@ bool CSE::processOpenExistentialRef(OpenExistentialRefInst *Inst,
 
       // Check if the result type depends on this specific opened existential.
       auto ResultDependsOnOldOpenedArchetype =
-          result->getType().getASTType().findIf(
-              [&OldOpenedArchetype](Type t) -> bool {
-                return (CanType(t) == OldOpenedArchetype);
-              });
+          result->getType().getASTType()->hasLocalArchetypeFromEnvironment(OldEnv);
 
       // If it does, the candidate depends on the opened existential.
       if (ResultDependsOnOldOpenedArchetype) {
diff --git a/lib/SILOptimizer/Transforms/CopyPropagation.cpp b/lib/SILOptimizer/Transforms/CopyPropagation.cpp
index e4fb0a24a74ce..67c606995e1fc 100644
--- a/lib/SILOptimizer/Transforms/CopyPropagation.cpp
+++ b/lib/SILOptimizer/Transforms/CopyPropagation.cpp
@@ -20,8 +20,8 @@
 /// This pass operates independently on each extended lifetime--the lifetime of
 /// an OSSA reference after propagating that reference through all copies. For
 /// owned references, this is a simple process of canonicalization that can be
-/// invoked separately via the CanonicalizeOSSALifetime utility. The
-/// CanonicalizeBorrowScope utility handles borrowed references, but this is
+/// invoked separately via the OSSACanonicalizeOwned utility. The
+/// OSSACanonicalizeGuaranteed utility handles borrowed references, but this is
 /// much more involved. It requires coordination to cleanup owned lifetimes
 /// outside the borrow scope after canonicalizing the scope itself.
 ///
@@ -59,9 +59,9 @@
 #include "swift/SILOptimizer/Analysis/DeadEndBlocksAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Passes.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstOptUtils.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "swift/SILOptimizer/Utils/OwnershipOptUtils.h"
 #include "llvm/ADT/SetVector.h"
 
@@ -102,13 +102,13 @@ struct CanonicalDefWorklist {
       return;
 
     while (true) {
-      def = CanonicalizeOSSALifetime::getCanonicalCopiedDef(def);
+      def = OSSACanonicalizeOwned::getCanonicalCopiedDef(def);
 
       // If the copy's source is guaranteed, find the root of a borrowed
       // extended lifetime.
       if (auto *copy = dyn_cast<CopyValueInst>(def)) {
         if (SILValue borrowDef =
-                CanonicalizeBorrowScope::getCanonicalBorrowedDef(
+                OSSACanonicalizeGuaranteed::getCanonicalBorrowedDef(
                     copy->getOperand())) {
           if (canonicalizeBorrows || isa<SILFunctionArgument>(borrowDef)) {
             borrowedValues.insert(borrowDef);
@@ -123,7 +123,7 @@ struct CanonicalDefWorklist {
       // Look through hoistable owned forwarding instructions on the
       // use-def chain.
       if (SILInstruction *defInst = def->getDefiningInstruction()) {
-        if (CanonicalizeBorrowScope::isRewritableOSSAForward(defInst)) {
+        if (OSSACanonicalizeGuaranteed::isRewritableOSSAForward(defInst)) {
           SILValue forwardedDef = defInst->getOperand(0);
           if (forwardedDef->getOwnershipKind() == OwnershipKind::Owned) {
             def = forwardedDef;
@@ -151,7 +151,7 @@ struct CanonicalDefWorklist {
         useWorklist.append(copy->getUses().begin(), copy->getUses().end());
         continue;
       }
-      if (!CanonicalizeBorrowScope::isRewritableOSSAForward(user))
+      if (!OSSACanonicalizeGuaranteed::isRewritableOSSAForward(user))
         continue;
 
       if (!ownedForwards.insert(user))
@@ -210,7 +210,7 @@ struct CanonicalDefWorklist {
 /// This allows the ownership of '%src' to be forwarded to its member.
 ///
 /// This utility runs during copy propagation as a prerequisite to
-/// CanonicalizeBorrowScopes.
+/// OSSACanonicalizeGuaranteeds.
 ///
 /// TODO: generalize this to handle multiple nondebug uses of the
 /// struct_extract.
@@ -359,7 +359,7 @@ static void findPreheadersOnControlEquivalentPath(
 /// Sink \p ownedForward to its uses.
 ///
 /// Owned forwarding instructions are identified by
-/// CanonicalizeOSSALifetime::isRewritableOSSAForward().
+/// OSSACanonicalizeOwned::isRewritableOSSAForward().
 ///
 /// Assumes that the uses of ownedForward jointly postdominate it (valid OSSA).
 ///
@@ -485,7 +485,7 @@ void CopyPropagation::propagateCopies(
 
   // canonicalizer performs all modifications through deleter's callbacks, so we
   // don't need to explicitly check for changes.
-  CanonicalizeOSSALifetime canonicalizer(
+  OSSACanonicalizeOwned canonicalizer(
       pruneDebug, MaximizeLifetime_t(!getFunction()->shouldOptimize()),
       getFunction(), accessBlockAnalysis, deadEndBlocksAnalysis, domTree,
       calleeAnalysis, deleter);
@@ -496,9 +496,9 @@ void CopyPropagation::propagateCopies(
     bool firstRun = true;
     // Run the sequence of utilities:
     // - ShrinkBorrowScope
-    // - CanonicalizeOSSALifetime(borrowee)
+    // - OSSACanonicalizeOwned(borrowee)
     // - LexicalDestroyFolding
-    // - CanonicalizeOSSALifetime(folded)
+    // - OSSACanonicalizeOwned(folded)
     // at least once and then until each stops making changes.
     while (true) {
       SmallVector<CopyValueInst *, 4> modifiedCopyValueInsts;
@@ -512,7 +512,7 @@ void CopyPropagation::propagateCopies(
       if (!shrunk && !firstRun)
         break;
 
-      // If borrowed value is not owned, neither CanonicalizeOSSALifetime nor
+      // If borrowed value is not owned, neither OSSACanonicalizeOwned nor
       // LexicalDestroyFolding will do anything with it.  Just bail out now.
       auto borrowee = bbi->getOperand();
       if (borrowee->getOwnershipKind() != OwnershipKind::Owned)
@@ -562,7 +562,7 @@ void CopyPropagation::propagateCopies(
   }
   // borrowCanonicalizer performs all modifications through deleter's
   // callbacks, so we don't need to explicitly check for changes.
-  CanonicalizeBorrowScope borrowCanonicalizer(f, deleter);
+  OSSACanonicalizeGuaranteed borrowCanonicalizer(f, deleter);
   // The utilities in this loop cannot delete borrows before they are popped
   // from the worklist.
   while (true) {
@@ -581,7 +581,7 @@ void CopyPropagation::propagateCopies(
       // Canonicalize a forwarded owned value before sinking the forwarding
       // instruction, and sink the instruction before canonicalizing the owned
       // value being forwarded. Process 'ownedForwards' in reverse since
-      // they may be chained, and CanonicalizeBorrowScopes pushes them
+      // they may be chained, and OSSACanonicalizeGuaranteeds pushes them
       // top-down.
       for (auto result : ownedForward->getResults()) {
         if (!continueWithNextSubpassRun(result))
@@ -596,10 +596,10 @@ void CopyPropagation::propagateCopies(
         // operand. This handles chained forwarding instructions that were
         // pushed onto the list out-of-order.
         if (SILInstruction *forwardDef =
-                CanonicalizeOSSALifetime::getCanonicalCopiedDef(
+                OSSACanonicalizeOwned::getCanonicalCopiedDef(
                     ownedForward->getOperand(0))
                     ->getDefiningInstruction()) {
-          if (CanonicalizeBorrowScope::isRewritableOSSAForward(forwardDef)) {
+          if (OSSACanonicalizeGuaranteed::isRewritableOSSAForward(forwardDef)) {
             defWorklist.ownedForwards.insert(forwardDef);
           }
         }
@@ -688,10 +688,10 @@ void CopyPropagation::verifyOwnership() {
                          : deBlocksAnalysis->get(f));
 }
 
-// MandatoryCopyPropagation is not currently enabled in the -Onone pipeline
-// because it may negatively affect the debugging experience.
+// MandatoryCopyPropagation runs in the -Onone pipeline and needs to be more
+// conservative, preserving debug information.
 SILTransform *swift::createMandatoryCopyPropagation() {
-  return new CopyPropagation(PruneDebugInsts, /*canonicalizeAll*/ true,
+  return new CopyPropagation(DontPruneDebugInsts, /*canonicalizeAll*/ true,
                              /*canonicalizeBorrows*/ false);
 }
 
diff --git a/lib/SILOptimizer/Transforms/DeadCodeElimination.cpp b/lib/SILOptimizer/Transforms/DeadCodeElimination.cpp
index 3df88969da85a..f79aab4be0a02 100644
--- a/lib/SILOptimizer/Transforms/DeadCodeElimination.cpp
+++ b/lib/SILOptimizer/Transforms/DeadCodeElimination.cpp
@@ -17,7 +17,7 @@
 #include "swift/SIL/DebugUtils.h"
 #include "swift/SIL/MemAccessUtils.h"
 #include "swift/SIL/NodeBits.h"
-#include "swift/SIL/OSSALifetimeCompletion.h"
+#include "swift/SIL/OSSACompleteLifetime.h"
 #include "swift/SIL/OwnershipUtils.h"
 #include "swift/SIL/SILArgument.h"
 #include "swift/SIL/SILBasicBlock.h"
@@ -77,6 +77,28 @@ static bool seemsUseful(SILInstruction *I) {
     return true;
   }
 
+  // Instructions which end the lifetimes of values which escape can only be
+  // deleted if compensating lifetime ends are added.  Compensating lifetime
+  // ends are added by OSSACompleteLifetime when the def block of the value
+  // is different from the parent block of the instruction.  But
+  // OSSACompleteLifetime requires that liveness be complete--that there are no
+  // pointer escapes.  So we can't delete instructions which end the lifetime
+  // of values which escape to a pointer and whose parent blocks are different.
+  if (llvm::any_of(I->getAllOperands(), [I](Operand &operand) {
+        if (!operand.isLifetimeEnding())
+          return false;
+        auto value = operand.get();
+        if (isa<SILUndef>(value))
+          return false;
+        auto *insertionPoint = value->getDefiningInsertionPoint();
+        ASSERT(insertionPoint);
+        if (insertionPoint->getParent() == I->getParent())
+          return false;
+        return findPointerEscape(value);
+      })) {
+    return true;
+  }
+
   if (auto *BI = dyn_cast<BuiltinInst>(I)) {
     // Although the onFastPath builtin has no side-effects we don't want to
     // remove it.
@@ -813,12 +835,12 @@ bool DCE::removeDead() {
     }
   }
 
-  OSSALifetimeCompletion completion(F, DT, *deadEndBlocks);
+  OSSACompleteLifetime completion(F, DT, *deadEndBlocks);
   for (auto value : valuesToComplete) {
     if (!value.has_value())
       continue;
     completion.completeOSSALifetime(*value,
-                                    OSSALifetimeCompletion::Boundary::Liveness);
+                                    OSSACompleteLifetime::Boundary::Liveness);
   }
 
   return Changed;
diff --git a/lib/SILOptimizer/Transforms/DeadObjectElimination.cpp b/lib/SILOptimizer/Transforms/DeadObjectElimination.cpp
index 6766f7b5ae5a4..b96f862b23b63 100644
--- a/lib/SILOptimizer/Transforms/DeadObjectElimination.cpp
+++ b/lib/SILOptimizer/Transforms/DeadObjectElimination.cpp
@@ -318,7 +318,8 @@ static bool canZapInstruction(SILInstruction *Inst, bool acceptRefCountInsts,
   // The value form of zero init is not a user of any operand. The address
   // form however is easily zappable because it's always a trivial store.
   if (auto bi = dyn_cast<BuiltinInst>(Inst)) {
-    if (bi->getBuiltinKind() == BuiltinValueKind::ZeroInitializer) {
+    if (bi->getBuiltinKind() == BuiltinValueKind::ZeroInitializer ||
+        bi->getBuiltinKind() == BuiltinValueKind::PrepareInitialization) {
       return true;
     }
   }
@@ -685,7 +686,7 @@ recursivelyCollectInteriorUses(ValueBase *DefInst,
         continue;
       }
       ArraySemanticsCall AS(svi);
-      if (AS.getKind() == swift::ArrayCallKind::kArrayFinalizeIntrinsic) {
+      if (AS.getKind() == ArrayCallKind::kArrayFinalizeIntrinsic) {
         if (!recursivelyCollectInteriorUses(svi, AddressNode, IsInteriorAddress))
           return false;
         continue;
diff --git a/lib/SILOptimizer/Transforms/DestroyAddrHoisting.cpp b/lib/SILOptimizer/Transforms/DestroyAddrHoisting.cpp
index 3cb17453efbf5..0566a1ce0fc80 100644
--- a/lib/SILOptimizer/Transforms/DestroyAddrHoisting.cpp
+++ b/lib/SILOptimizer/Transforms/DestroyAddrHoisting.cpp
@@ -164,6 +164,20 @@ struct KnownStorageUses : UniqueStorageUseVisitor {
   bool visitStore(Operand *use) override { return recordUser(use->getUser()); }
 
   bool visitDestroy(Operand *use) override {
+    // An init_enum_data_addr is viewed as an "identity projection", rather than
+    // a proper projection like a struct_element_addr.  As a result, its
+    // destroys are passed directly to visitors.  But such addresses aren't
+    // quite equivalent to the original address.  Specifically, a destroy of an
+    // init_enum_data_addr cannot in general be replaced with a destroy of the
+    // whole enum.  The latter destroy is only equivalent to the former if there
+    // has been an `inject_enum_addr`.
+    //
+    // Handle a destroy of such a projection just like we handle the destroy of
+    // a struct_element_addr: by bailing out.
+    if (isa<InitEnumDataAddrInst>(
+            stripAccessAndAccessStorageCasts(use->get()))) {
+      return false;
+    }
     originalDestroys.insert(use->getUser());
     return true;
   }
@@ -604,7 +618,7 @@ bool HoistDestroys::foldBarrier(SILInstruction *barrier,
   SmallPtrSet<AccessPath::PathNode, 16> trivialLeaves;
 
   bool succeeded = visitProductLeafAccessPathNodes(
-      storageRoot, typeExpansionContext, module,
+      storageRoot, typeExpansionContext, *function,
       [&](AccessPath::PathNode node, SILType ty) {
         if (ty.isTrivial(*function))
           return;
@@ -727,6 +741,11 @@ bool HoistDestroys::checkFoldingBarrier(
     auto loadee = load->getOperand();
     auto relativeAccessStorage = RelativeAccessStorageWithBase::compute(loadee);
     if (relativeAccessStorage.getStorage().hasIdenticalStorage(storage)) {
+      // Only fold into access scopes which aren't [read].
+      auto scoped = AccessStorageWithBase::computeInScope(loadee);
+      auto *bai = dyn_cast_or_null<BeginAccessInst>(scoped.base);
+      if (bai && bai->getAccessKind() == SILAccessKind::Read)
+        return true;
       // If the access path from the loaded address to its root storage involves
       // a (layout non-equivalent) typecast--a load [take] of the casted address
       // would not be equivalent to a load [copy] followed by a destroy_addr of
@@ -746,6 +765,11 @@ bool HoistDestroys::checkFoldingBarrier(
     auto source = copy->getSrc();
     auto relativeAccessStorage = RelativeAccessStorageWithBase::compute(source);
     if (relativeAccessStorage.getStorage().hasIdenticalStorage(storage)) {
+      // Only fold into access scopes which aren't [read].
+      auto scoped = AccessStorageWithBase::computeInScope(source);
+      auto *bai = dyn_cast_or_null<BeginAccessInst>(scoped.base);
+      if (bai && bai->getAccessKind() == SILAccessKind::Read)
+        return true;
       // If the access path from the copy_addr'd address to its root storage
       // involves a (layout non-equivalent) typecast--a copy_addr [take] of the
       // casted address would not be equivalent to a copy_addr followed by a
@@ -765,7 +789,7 @@ bool HoistDestroys::checkFoldingBarrier(
     bool alreadySawLeaf = false;
     bool alreadySawTrivialSubleaf = false;
     auto succeeded = visitProductLeafAccessPathNodes(
-        address, typeExpansionContext, module,
+        address, typeExpansionContext, *function,
         [&](AccessPath::PathNode node, SILType ty) {
           if (ty.isTrivial(*function)) {
             bool inserted = !trivialLeaves.insert(node).second;
diff --git a/lib/SILOptimizer/Transforms/EagerSpecializer.cpp b/lib/SILOptimizer/Transforms/EagerSpecializer.cpp
index fd2cf1d55f936..13556037605b5 100644
--- a/lib/SILOptimizer/Transforms/EagerSpecializer.cpp
+++ b/lib/SILOptimizer/Transforms/EagerSpecializer.cpp
@@ -495,12 +495,10 @@ emitTypeCheck(SILBasicBlock *FailedTypeCheckBB, SubstitutableType *ParamTy,
   Builder.emitBlock(SuccessBB);
 }
 
-static SubstitutionMap getSingleSubstitutionMap(SILFunction *F,
-                                                  Type Ty) {
+static SubstitutionMap getSingleSubstitutionMap(SILFunction *F, Type Ty) {
   return SubstitutionMap::get(
-    F->getGenericEnvironment()->getGenericSignature(),
-    [&](SubstitutableType *type) { return Ty; },
-    MakeAbstractConformanceForGenericType());
+    F->getGenericEnvironment()->getGenericSignature(), Ty,
+    LookUpConformanceInModule());
 }
 
 void EagerDispatch::emitIsTrivialCheck(SILBasicBlock *FailedTypeCheckBB,
diff --git a/lib/SILOptimizer/Transforms/GenericSpecializer.cpp b/lib/SILOptimizer/Transforms/GenericSpecializer.cpp
index 93dd7cdd99dcb..6d87817717690 100644
--- a/lib/SILOptimizer/Transforms/GenericSpecializer.cpp
+++ b/lib/SILOptimizer/Transforms/GenericSpecializer.cpp
@@ -40,8 +40,8 @@ static void transferSpecializeAttributeTargets(SILModule &M,
                                                SILOptFunctionBuilder &builder,
                                                Decl *d) {
   auto *vd = cast<AbstractFunctionDecl>(d);
-  for (auto *A : vd->getAttrs().getAttributes<SpecializeAttr>()) {
-    auto *SA = cast<SpecializeAttr>(A);
+  for (auto *A : vd->getAttrs().getAttributes<AbstractSpecializeAttr>()) {
+    auto *SA = cast<AbstractSpecializeAttr>(A);
     // Filter _spi.
     auto spiGroups = SA->getSPIGroups();
     auto hasSPIGroup = !spiGroups.empty();
@@ -107,6 +107,16 @@ bool swift::specializeAppliesInFunction(SILFunction &F,
       if (!Callee)
         continue;
 
+      // TODO: Enable GenericSpecializer for borrow accessors in OSSA
+      // Currently disabled since GenericSpecializer generates store_borrow to a
+      // temporary stack location and returns a projection from the
+      // store_borrow. This does not work for borrow accessors that return the
+      // projection from within the store_borrow scope.
+      if (F.hasOwnership() &&
+          Callee->getConventions().hasGuaranteedAddressResult()) {
+        continue;
+      }
+
       FunctionBuilder.getModule().performOnceForPrespecializedImportedExtensions(
         [&FunctionBuilder](AbstractFunctionDecl *pre) {
         transferSpecializeAttributeTargets(FunctionBuilder.getModule(), FunctionBuilder,
diff --git a/lib/SILOptimizer/Transforms/PerformanceInliner.cpp b/lib/SILOptimizer/Transforms/PerformanceInliner.cpp
index 6c9edcd66aeef..b6b682b01238e 100644
--- a/lib/SILOptimizer/Transforms/PerformanceInliner.cpp
+++ b/lib/SILOptimizer/Transforms/PerformanceInliner.cpp
@@ -73,6 +73,108 @@ llvm::cl::opt<bool> EnableVerifyAfterEachInlining(
         "Run sil verification after inlining each found callee apply "
         "site into a caller."));
 
+//===----------------------------------------------------------------------===//
+//                           Heuristics
+//===----------------------------------------------------------------------===//
+
+/// The following constants define the cost model for inlining. Some constants
+/// are also defined in ShortestPathAnalysis.
+
+llvm::cl::opt<int> RemovedCallBenefit(
+    "sil-inline-removed-call-benefit", llvm::cl::init(20),
+    llvm::cl::desc("The base value for every call: it represents the benefit "
+                   "of removing the call overhead itself."));
+
+llvm::cl::opt<int> RemovedCoroutineCallBenefit(
+    "sil-inline-removed-coroutine-call-benefit", llvm::cl::init(300),
+    llvm::cl::desc("The benefit of inlining a `begin_apply`."));
+
+llvm::cl::opt<int> RemovedClosureBenefit(
+    "sil-inline-removed-closure-benefit",
+    llvm::cl::init(RemovedCallBenefit + 50),
+    llvm::cl::desc(
+        "The benefit if the operand of an apply gets constant e.g. if a "
+        "closure is passed to an apply instruction in the callee."));
+
+llvm::cl::opt<int> RemovedLoadBenefit(
+    "sil-inline-removed-load-benefit", llvm::cl::init(RemovedCallBenefit + 5),
+    llvm::cl::desc("The benefit if a load can (probably) eliminated because it "
+                   "loads from a stack location in the caller."));
+
+llvm::cl::opt<int> RemovedStoreBenefit(
+    "sil-inline-removed-store-benefit", llvm::cl::init(RemovedCallBenefit + 10),
+    llvm::cl::desc("The benefit if a store can (probably) eliminated because "
+                   "it stores to a stack location in the caller."));
+
+llvm::cl::opt<int> RemovedTerminatorBenefit(
+    "sil-inline-removed-terminator-benefit",
+    llvm::cl::init(RemovedCallBenefit + 10),
+    llvm::cl::desc("The benefit if the condition of a terminator instruction "
+                   "gets constant due to inlining."));
+
+llvm::cl::opt<int>
+    RefCountBenefit("sil-inline-ref-count-benefit",
+                    llvm::cl::init(RemovedCallBenefit + 20),
+                    llvm::cl::desc("The benefit if a retain/release can "
+                                   "(probably) be eliminated after inlining."));
+
+llvm::cl::opt<int> FastPathBuiltinBenefit(
+    "sil-inline-fast-path-builtin-benefit",
+    llvm::cl::init(RemovedCallBenefit + 40),
+    llvm::cl::desc("The benefit of a onFastPath builtin."));
+
+llvm::cl::opt<int> DevirtualizedCallBenefit(
+    "sil-inline-devirtualized-call-benefit",
+    llvm::cl::init(RemovedCallBenefit + 300),
+    llvm::cl::desc("The benefit of being able to devirtualize a call."));
+
+llvm::cl::opt<int> GenericSpecializationBenefit(
+    "sil-inline-generic-specialization-benefit",
+    llvm::cl::init(RemovedCallBenefit + 300),
+    llvm::cl::desc("The benefit of being able to produce a generic "
+                   "specialization for a call."));
+
+llvm::cl::opt<int> ExclusivityBenefit(
+    "sil-inline-exclusivity-benefit", llvm::cl::init(RemovedCallBenefit + 10),
+    llvm::cl::desc("The benefit of inlining an exclusivity-containing callee. "
+                   "The exclusivity needs to be: dynamic, has no nested "
+                   "conflict and addresses known storage"));
+
+llvm::cl::opt<int> OSizeClassMethodBenefit(
+    "sil-inline-o-size-class-method-benefit", llvm::cl::init(5),
+    llvm::cl::desc("The benefit of inlining class methods with -Osize. We only "
+                   "inline very small class methods with -Osize."));
+
+llvm::cl::opt<int> GlobalInitBenefit(
+    "sil-inline-global-init-benefit", llvm::cl::init(100),
+    llvm::cl::desc("The benefit of inlining constructors into global initializers."));
+
+llvm::cl::opt<int> TrivialFunctionThreshold(
+    "sil-inline-trivial-function-threshold", llvm::cl::init(18),
+    llvm::cl::desc("Approximately up to this cost level a function can be "
+                   "inlined without increasing the code size."));
+
+llvm::cl::opt<int> BlockLimitDenominator(
+    "sil-inline-block-limit-denominator", llvm::cl::init(3000),
+    llvm::cl::desc("Configuration for the \"soft\" caller block limit. When "
+                   "changing make sure you update BlockLimitMaxIntNumerator."));
+
+llvm::cl::opt<int> BlockLimitMaxIntNumerator(
+    "sil-inline-block-limit-max-int-numerator", llvm::cl::init(18608),
+    llvm::cl::desc("Computations with BlockLimitDenominator will overflow with "
+                   "numerators >= this value. This equals cbrt(INT_MAX) * "
+                   "cbrt(BlockLimitDenominator); we hardcode its value because "
+                   "std::cbrt() is not constexpr."));
+
+llvm::cl::opt<int> OverallCallerBlockLimit(
+    "sil-inline-overall-caller-block-limit", llvm::cl::init(400),
+    llvm::cl::desc("No inlining is done if the caller has more than this "
+                   "number of blocks."));
+
+llvm::cl::opt<int> DefaultApplyLength(
+    "sil-inline-default-apply-length", llvm::cl::init(10),
+    llvm::cl::desc("The assumed execution length of a function call."));
+
 //===----------------------------------------------------------------------===//
 //                           Printing Helpers
 //===----------------------------------------------------------------------===//
@@ -118,75 +220,6 @@ class SILPerformanceInliner {
 
   OptRemark::Emitter &ORE;
 
-  /// The following constants define the cost model for inlining. Some constants
-  /// are also defined in ShortestPathAnalysis.
-  enum {
-    /// The base value for every call: it represents the benefit of removing the
-    /// call overhead itself.
-    RemovedCallBenefit = 20,
-
-    /// The benefit of inlining a `begin_apply`.
-    RemovedCoroutineCallBenefit = 300,
-
-    /// The benefit if the operand of an apply gets constant, e.g. if a closure
-    /// is passed to an apply instruction in the callee.
-    RemovedClosureBenefit = RemovedCallBenefit + 50,
-
-    /// The benefit if a load can (probably) eliminated because it loads from
-    /// a stack location in the caller.
-    RemovedLoadBenefit = RemovedCallBenefit + 5,
-
-    /// The benefit if a store can (probably) eliminated because it stores to
-    /// a stack location in the caller.
-    RemovedStoreBenefit = RemovedCallBenefit + 10,
-
-    /// The benefit if the condition of a terminator instruction gets constant
-    /// due to inlining.
-    RemovedTerminatorBenefit = RemovedCallBenefit + 10,
-
-    /// The benefit if a retain/release can (probably) be eliminated after
-    /// inlining.
-    RefCountBenefit = RemovedCallBenefit + 20,
-
-    /// The benefit of a onFastPath builtin.
-    FastPathBuiltinBenefit = RemovedCallBenefit + 40,
-
-    /// The benefit of being able to devirtualize a call.
-    DevirtualizedCallBenefit = RemovedCallBenefit + 300,
-
-    /// The benefit of being able to produce a generic
-    /// specialization for a call.
-    GenericSpecializationBenefit = RemovedCallBenefit + 300,
-
-    /// The benefit of inlining an exclusivity-containing callee.
-    /// The exclusivity needs to be: dynamic,
-    /// has no nested conflict and addresses known storage
-    ExclusivityBenefit = RemovedCallBenefit + 10,
-
-    /// The benefit of inlining class methods with -Osize.
-    /// We only inline very small class methods with -Osize.
-    OSizeClassMethodBenefit = 5,
-
-    /// Approximately up to this cost level a function can be inlined without
-    /// increasing the code size.
-    TrivialFunctionThreshold = 18,
-
-    /// Configuration for the "soft" caller block limit. When changing, make
-    /// sure you update BlockLimitMaxIntNumerator.
-    BlockLimitDenominator = 3000,
-
-    /// Computations with BlockLimitDenominator will overflow with numerators
-    /// >= this value. This equals cbrt(INT_MAX) * cbrt(BlockLimitDenominator);
-    /// we hardcode its value because std::cbrt() is not constexpr.
-    BlockLimitMaxIntNumerator = 18608,
-
-    /// No inlining is done if the caller has more than this number of blocks.
-    OverallCallerBlockLimit = 400,
-
-    /// The assumed execution length of a function call.
-    DefaultApplyLength = 10
-  };
-
   OptimizationMode OptMode;
 
 #ifndef NDEBUG
@@ -416,6 +449,14 @@ bool isFunctionAutodiffVJP(SILFunction *callee) {
   return false;
 }
 
+bool isAllocator(SILFunction *callee) {
+  swift::Demangle::Context Ctx;
+  if (auto *Root = Ctx.demangleSymbolAsNode(callee->getName())) {
+    return Root->findByKind(swift::Demangle::Node::Kind::Allocator, 3) != nullptr;
+  }
+  return false;
+}
+
 bool isProfitableToInlineAutodiffVJP(SILFunction *vjp, SILFunction *caller,
                                      InlineSelection whatToInline,
                                      StringRef stageName) {
@@ -483,6 +524,14 @@ static bool hasConstantArguments(FullApplySite fas) {
   return true;
 }
 
+static bool hasConstantEnumArgument(FullApplySite fas) {
+  for (SILValue arg : fas.getArguments()) {
+    if (isa<EnumInst>(arg))
+      return true;
+  }
+  return false;
+}
+
 bool SILPerformanceInliner::isProfitableToInline(
     FullApplySite AI, Weight CallerWeight, ConstantTracker &callerTracker,
     int &NumCallerBlocks,
@@ -556,6 +605,13 @@ bool SILPerformanceInliner::isProfitableToInline(
     return true;
   }
 
+  // If there is a "constant" enum argument to a synthesized enum comparison,
+  // we can always inline it, because most of it will be constant folded anyway.
+  if (Callee->hasSemanticsAttr(semantics::DERIVED_ENUM_EQUALS) &&
+      hasConstantEnumArgument(AI)) {
+    return true;
+  }
+
   // Bail out if this generic call can be optimized by means of
   // the generic specialization, because we prefer generic specialization
   // to inlining of generics.
@@ -577,7 +633,7 @@ bool SILPerformanceInliner::isProfitableToInline(
     CalleeSPA->analyze(CBI, [](FullApplySite FAS) {
       // We don't compute SPA for another call-level. Functions called from
       // the callee are assumed to have DefaultApplyLength.
-      return DefaultApplyLength;
+      return DefaultApplyLength.getValue();
     });
   }
 
@@ -756,6 +812,12 @@ bool SILPerformanceInliner::isProfitableToInline(
     Benefit = std::max(Benefit, ExclusivityBenefitWeight);
   }
 
+  if (AI.getFunction()->isGlobalInitOnceFunction() && isAllocator(Callee)) {
+    // Inlining constructors into global initializers increase the changes that
+    // the global can be initialized statically.
+    CallerWeight.updateBenefit(Benefit, GlobalInitBenefit);
+  }
+
   if (AI.getFunction()->isThunk()) {
     // Only inline trivial functions into thunks (which will not increase the
     // code size).
@@ -864,7 +926,9 @@ static bool hasMaxNumberOfBasicBlocks(SILFunction *f, int limit) {
 static bool isInlineAlwaysCallSite(SILFunction *Callee, int numCallerBlocks) {
   if (Callee->isTransparent())
     return true;
-  if (Callee->getInlineStrategy() == AlwaysInline &&
+  if (Callee->getInlineStrategy() == AlwaysInline)
+    return true;
+  if (Callee->getInlineStrategy() == HeuristicAlwaysInline &&
       !Callee->getModule().getOptions().IgnoreAlwaysInline &&
 
       // Protect against misuse of @inline(__always).
@@ -1129,7 +1193,7 @@ void SILPerformanceInliner::collectAppliesToInline(
         CalleeSPA->analyze(CBI, [](FullApplySite FAS) {
           // We don't compute SPA for another call-level. Functions called from
           // the callee are assumed to have DefaultApplyLength.
-          return DefaultApplyLength;
+          return DefaultApplyLength.getValue();
         });
       }
       int CalleeLength = CalleeSPA->getScopeLength(&Callee->front(), 0);
diff --git a/lib/SILOptimizer/Transforms/SILMem2Reg.cpp b/lib/SILOptimizer/Transforms/SILMem2Reg.cpp
index b4798ceb44084..dd9b2a7f384a7 100644
--- a/lib/SILOptimizer/Transforms/SILMem2Reg.cpp
+++ b/lib/SILOptimizer/Transforms/SILMem2Reg.cpp
@@ -27,7 +27,7 @@
 #include "swift/Basic/TaggedUnion.h"
 #include "swift/SIL/BasicBlockDatastructures.h"
 #include "swift/SIL/Dominance.h"
-#include "swift/SIL/OSSALifetimeCompletion.h"
+#include "swift/SIL/OSSACompleteLifetime.h"
 #include "swift/SIL/Projection.h"
 #include "swift/SIL/SILBuilder.h"
 #include "swift/SIL/SILFunction.h"
@@ -40,9 +40,9 @@
 #include "swift/SILOptimizer/PassManager/Passes.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Utils/CFGOptUtils.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstOptUtils.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "swift/SILOptimizer/Utils/OwnershipOptUtils.h"
 #include "swift/SILOptimizer/Utils/ScopeOptUtils.h"
 #include "llvm/ADT/DenseMap.h"
@@ -123,8 +123,7 @@ class LiveValues {
     }
 
     void endLexicalLifetimeBeforeInst(AllocStackInst *asi,
-                                      SILInstruction *beforeInstruction,
-                                      SILBuilderContext &ctx);
+                                      SILInstruction *beforeInstruction);
   };
   struct Guaranteed {
     SILValue stored = SILValue();
@@ -173,8 +172,7 @@ class LiveValues {
     }
 
     void endLexicalLifetimeBeforeInst(AllocStackInst *asi,
-                                      SILInstruction *beforeInstruction,
-                                      SILBuilderContext &ctx);
+                                      SILInstruction *beforeInstruction);
   };
   struct None {
     SILValue stored = SILValue();
@@ -190,8 +188,7 @@ class LiveValues {
     bool canEndLexicalLifetime() { return false; }
 
     void endLexicalLifetimeBeforeInst(AllocStackInst *asi,
-                                      SILInstruction *beforeInstruction,
-                                      SILBuilderContext &ctx);
+                                      SILInstruction *beforeInstruction);
   };
 
 private:
@@ -289,15 +286,14 @@ class LiveValues {
   }
 
   void endLexicalLifetimeBeforeInst(AllocStackInst *asi,
-                                    SILInstruction *beforeInstruction,
-                                    SILBuilderContext &ctx) {
+                                    SILInstruction *beforeInstruction) {
     if (auto *owned = storage.dyn_cast<Owned>()) {
-      return owned->endLexicalLifetimeBeforeInst(asi, beforeInstruction, ctx);
+      return owned->endLexicalLifetimeBeforeInst(asi, beforeInstruction);
     } else if (auto *none = storage.dyn_cast<None>()) {
-      return none->endLexicalLifetimeBeforeInst(asi, beforeInstruction, ctx);
+      return none->endLexicalLifetimeBeforeInst(asi, beforeInstruction);
     }
     auto &guaranteed = storage.get<Guaranteed>();
-    return guaranteed.endLexicalLifetimeBeforeInst(asi, beforeInstruction, ctx);
+    return guaranteed.endLexicalLifetimeBeforeInst(asi, beforeInstruction);
   }
 
   bool endLexicalLifetimeBeforeInstIfPossible(AllocStackInst *asi,
@@ -305,7 +301,7 @@ class LiveValues {
                                               SILBuilderContext &ctx) {
     if (!canEndLexicalLifetime())
       return false;
-    endLexicalLifetimeBeforeInst(asi, beforeInstruction, ctx);
+    endLexicalLifetimeBeforeInst(asi, beforeInstruction);
     return true;
   }
 };
@@ -392,6 +388,17 @@ static bool isLoadFromStack(SILInstruction *i, AllocStackInst *asi) {
   return true;
 }
 
+/// Whether the storage is invalid after \p i.
+///
+/// This is exactly when the instruction is a load [take].
+static bool doesLoadInvalidateStorage(SILInstruction *i) {
+  auto *li = dyn_cast<LoadInst>(i);
+  if (!li) {
+    return false;
+  }
+  return li->getOwnershipQualifier() == LoadOwnershipQualifier::Take;
+}
+
 /// Collects all load instructions which (transitively) use \p i as address.
 static void collectLoads(SILInstruction *i,
                          SmallVectorImpl<SILInstruction *> &foundLoads) {
@@ -438,6 +445,16 @@ static bool isAddressForLoad(SILInstruction *load, SILBasicBlock *&singleBlock,
       !isa<TupleElementAddrInst>(load))
     return false;
 
+  // In OSSA, the result of an unchecked_bitwise_cast must immediately be
+  // copied or unchecked_bitwise_cast'd again.  In particular, it is not
+  // permitted to borrow it and perform additional projections (struct_extract,
+  // tuple_extract) on the borrowed value.  Consequently, we cannot promote an
+  // address if such a promotion would result in such a pattern.
+  if (load->getFunction()->hasOwnership() &&
+      isa<UncheckedAddrCastInst>(load->getOperand(0)) &&
+      !isa<UncheckedAddrCastInst>(load))
+    return false;
+
   // None of the projections are lowered to owned values:
   //
   // struct_element_addr and tuple_element_addr instructions are lowered to
@@ -801,8 +818,7 @@ beginGuaranteedLexicalLifetimeAfterStore(AllocStackInst *asi,
 /// it will already have been ended naturally by destroy_addrs (or equivalent)
 /// of the alloc_stack.
 void LiveValues::Owned::endLexicalLifetimeBeforeInst(
-    AllocStackInst *asi, SILInstruction *beforeInstruction,
-    SILBuilderContext &ctx) {
+    AllocStackInst *asi, SILInstruction *beforeInstruction) {
   assert(lexicalLifetimeEnsured(asi));
   assert(beforeInstruction);
 }
@@ -810,8 +826,7 @@ void LiveValues::Owned::endLexicalLifetimeBeforeInst(
 /// End the lexical borrow scope for an @guaranteed stored value described by
 /// the provided LiveValues struct before the specified instruction.
 void LiveValues::Guaranteed::endLexicalLifetimeBeforeInst(
-    AllocStackInst *asi, SILInstruction *beforeInstruction,
-    SILBuilderContext &ctx) {
+    AllocStackInst *asi, SILInstruction *beforeInstruction) {
   assert(lexicalLifetimeEnsured(asi));
   assert(beforeInstruction);
   assert(borrow);
@@ -821,8 +836,7 @@ void LiveValues::Guaranteed::endLexicalLifetimeBeforeInst(
 }
 
 void LiveValues::None::endLexicalLifetimeBeforeInst(
-    AllocStackInst *asi, SILInstruction *beforeInstruction,
-    SILBuilderContext &ctx) {
+    AllocStackInst *asi, SILInstruction *beforeInstruction) {
   llvm::report_fatal_error(
       "can't have lexical lifetime for ownership none value");
 }
@@ -1051,7 +1065,7 @@ SILInstruction *StackAllocationPromoter::promoteAllocationInBlock(
           if (runningVals && runningVals->value.canEndLexicalLifetime()) {
             // End it right now if we have enough information.
             runningVals->value.getOwned().endLexicalLifetimeBeforeInst(
-                asi, /*beforeInstruction=*/li, ctx);
+                asi, /*beforeInstruction=*/li);
           } else {
             // If we don't have enough information, end it endLexicalLifetime.
             assert(!deinitializationPoints[blockPromotingWithin]);
@@ -1078,7 +1092,7 @@ SILInstruction *StackAllocationPromoter::promoteAllocationInBlock(
         // StackAllocationPromoter::fixBranchesAndUses will later handle it.
         LLVM_DEBUG(llvm::dbgs() << "*** First load: " << *li);
         runningVals = {LiveValues::toReplace(asi, /*replacement=*/li),
-                       /*isStorageValid=*/true};
+                       /*isStorageValid=*/!doesLoadInvalidateStorage(inst)};
       }
       continue;
     }
@@ -1133,7 +1147,7 @@ SILInstruction *StackAllocationPromoter::promoteAllocationInBlock(
         if (oldRunningVals && oldRunningVals->isStorageValid &&
             oldRunningVals->value.canEndLexicalLifetime()) {
           oldRunningVals->value.getOwned().endLexicalLifetimeBeforeInst(
-              asi, /*beforeInstruction=*/si, ctx);
+              asi, /*beforeInstruction=*/si);
         }
         runningVals = beginOwnedLexicalLifetimeAfterStore(asi, si);
       }
@@ -1165,9 +1179,6 @@ SILInstruction *StackAllocationPromoter::promoteAllocationInBlock(
 
     // End the lexical lifetime of the store_borrow source.
     if (auto *ebi = dyn_cast<EndBorrowInst>(inst)) {
-      if (!lexicalLifetimeEnsured(asi, lastStoreInst)) {
-        continue;
-      }
       auto *sbi = dyn_cast<StoreBorrowInst>(ebi->getOperand());
       if (!sbi) {
         continue;
@@ -1186,8 +1197,10 @@ SILInstruction *StackAllocationPromoter::promoteAllocationInBlock(
       if (sbi->getSrc() != runningVals->value.getStored()) {
         continue;
       }
-      // Mark storage as invalid and mark end_borrow as a deinit point.
       runningVals->isStorageValid = false;
+      if (!lexicalLifetimeEnsured(asi, lastStoreInst)) {
+        continue;
+      }
       runningVals->value.endLexicalLifetimeBeforeInstIfPossible(
           asi, ebi->getNextInstruction(), ctx);
       continue;
@@ -1204,6 +1217,7 @@ SILInstruction *StackAllocationPromoter::promoteAllocationInBlock(
         continue;
       }
       if (runningVals) {
+        assert(runningVals->isStorageValid);
         replaceDestroy(dai, runningVals->value.replacement(asi, dai), ctx,
                        deleter, instructionsToDelete);
         if (lexicalLifetimeEnsured(asi, lastStoreInst)) {
@@ -1813,8 +1827,15 @@ void StackAllocationPromoter::run(BasicBlockSetVector &livePhiBlocks) {
   deleter.forceDeleteWithUsers(asi);
 
   // Now, complete lifetimes!
-  OSSALifetimeCompletion completion(function, domInfo,
-                                    *deadEndBlocksAnalysis->get(function));
+  // We know that the incomplete values are trivial enum cases. Therefore we
+  // complete their lifetimes with `end_lifetime` instead of `destroy_value`.
+  // This is especially important for embedded swift where we are not allowed
+  // to insert destroys which were not there before.
+  OSSACompleteLifetime completion(function, domInfo,
+                                  *deadEndBlocksAnalysis->get(function),
+                                  OSSACompleteLifetime::IgnoreTrivialVariable,
+                                  /*forceLivenessVerification=*/false,
+                                  /*nonDestroyingEnd=*/true);
 
   // We may have incomplete lifetimes for enum locations on trivial paths.
   // After promoting them, complete lifetime here.
@@ -1822,7 +1843,7 @@ void StackAllocationPromoter::run(BasicBlockSetVector &livePhiBlocks) {
     // Set forceBoundaryCompletion as true so that we complete at boundary for
     // lexical values as well.
     completion.completeOSSALifetime(it,
-                                    OSSALifetimeCompletion::Boundary::Liveness);
+                                    OSSACompleteLifetime::Boundary::Liveness);
   }
 }
 
@@ -1951,9 +1972,8 @@ void MemoryToRegisters::removeSingleBlockAllocation(AllocStackInst *asi) {
             LiveValues::toReplace(asi,
                                   /*replacement=*/createEmptyAndUndefValue(
                                       asi->getElementType(), inst, ctx)),
-            /*isStorageValid=*/true};
+            /*isStorageValid=*/!doesLoadInvalidateStorage(inst)};
       }
-      assert(runningVals && runningVals->isStorageValid);
       auto *loadInst = dyn_cast<LoadInst>(inst);
       if (loadInst &&
           loadInst->getOwnershipQualifier() == LoadOwnershipQualifier::Take) {
@@ -2022,13 +2042,13 @@ void MemoryToRegisters::removeSingleBlockAllocation(AllocStackInst *asi) {
       if (!runningVals.has_value()) {
         continue;
       }
-      if (!runningVals->value.isGuaranteed()) {
-        continue;
-      }
       if (sbi->getSrc() != runningVals->value.getStored()) {
         continue;
       }
       runningVals->isStorageValid = false;
+      if (!runningVals->value.isGuaranteed()) {
+        continue;
+      }
       runningVals->value.endLexicalLifetimeBeforeInstIfPossible(
           asi, ebi->getNextInstruction(), ctx);
       continue;
@@ -2077,24 +2097,32 @@ void MemoryToRegisters::removeSingleBlockAllocation(AllocStackInst *asi) {
     }
   }
 
-  if (lexicalLifetimeEnsured(asi) && runningVals &&
-      runningVals->isStorageValid &&
-      runningVals->value.getStored()->getOwnershipKind().isCompatibleWith(
-          OwnershipKind::Owned)) {
-    // There is still valid storage after visiting all instructions in this
-    // block which are the only instructions involving this alloc_stack.
-    // This can only happen if all paths from this block end in unreachable.
-    //
-    // We need to end the lexical lifetime at the last possible location, at the
-    // boundary blocks which are the predecessors of dominance frontier
-    // dominated by the alloc_stack.
-    SmallVector<SILBasicBlock *, 4> boundary;
-    computeDominatedBoundaryBlocks(asi->getParent(), domInfo, boundary);
-    for (auto *block : boundary) {
-      auto *terminator = block->getTerminator();
-      runningVals->value.endLexicalLifetimeBeforeInstIfPossible(
-          asi, /*beforeInstruction=*/terminator, ctx);
-    }
+  auto *function = asi->getFunction();
+  if (!function->hasOwnership() || !runningVals ||
+      !runningVals->isStorageValid ||
+      asi->getElementType().isTrivial(function)) {
+    return;
+  }
+  // There is still valid storage after visiting all instructions in this
+  // block which are the only instructions involving this alloc_stack.
+  // That can happen if:
+  // (1) this block is a dead-end. TODO: OSSACompleteLifetime: Complete such
+  //                                     lifetimes.
+  // (2) a trivial case of a non-trivial enum was stored to the address
+
+  auto *deadEndBlocks = deadEndBlocksAnalysis->get(function);
+
+  if (!deadEndBlocks->isDeadEnd(parentBlock)) {
+    // We may have incomplete lifetimes for enum locations on trivial paths.
+    // After promoting them, complete lifetime here.
+    ASSERT(asi->getElementType().isOrHasEnum());
+    OSSACompleteLifetime completion(function, domInfo, *deadEndBlocks,
+                                    OSSACompleteLifetime::IgnoreTrivialVariable,
+                                    /*forceLivenessVerification=*/false,
+                                    /*nonDestroyingEnd=*/true);
+    completion.completeOSSALifetime(
+        runningVals->value.replacement(asi, nullptr),
+        OSSACompleteLifetime::Boundary::Liveness);
   }
 }
 
@@ -2139,28 +2167,29 @@ void MemoryToRegisters::canonicalizeValueLifetimes(
       break;
     }
   }
-  CanonicalizeOSSALifetime canonicalizer(
+  OSSACanonicalizeOwned canonicalizer(
       PruneDebugInsts, MaximizeLifetime_t(!f.shouldOptimize()), &f,
       accessBlockAnalysis, deadEndBlocksAnalysis, domInfo, calleeAnalysis,
       deleter);
   for (auto value : owned) {
     if (isa<SILUndef>(value) || value->isMarkedAsDeleted())
       continue;
-    auto root = CanonicalizeOSSALifetime::getCanonicalCopiedDef(value);
+    auto root = OSSACanonicalizeOwned::getCanonicalCopiedDef(value);
     if (auto *copy = dyn_cast<CopyValueInst>(root)) {
-      if (SILValue borrowDef = CanonicalizeBorrowScope::getCanonicalBorrowedDef(
-              copy->getOperand())) {
+      if (SILValue borrowDef =
+              OSSACanonicalizeGuaranteed::getCanonicalBorrowedDef(
+                  copy->getOperand())) {
         guaranteed.push_back(copy);
         continue;
       }
     }
     canonicalizer.canonicalizeValueLifetime(root);
   }
-  CanonicalizeBorrowScope borrowCanonicalizer(&f, deleter);
+  OSSACanonicalizeGuaranteed borrowCanonicalizer(&f, deleter);
   for (auto value : guaranteed) {
     if (isa<SILUndef>(value) || value->isMarkedAsDeleted())
       continue;
-    auto borrowee = CanonicalizeBorrowScope::getCanonicalBorrowedDef(value);
+    auto borrowee = OSSACanonicalizeGuaranteed::getCanonicalBorrowedDef(value);
     if (!borrowee)
       continue;
     BorrowedValue borrow(borrowee);
@@ -2193,7 +2222,8 @@ bool MemoryToRegisters::promoteAllocation(AllocStackInst *alloc,
   }
 
   // Remove write-only AllocStacks.
-  if (isWriteOnlyAllocation(alloc) && !lexicalLifetimeEnsured(alloc)) {
+  if (isWriteOnlyAllocation(alloc) && !alloc->getType().isOrHasEnum() &&
+      !lexicalLifetimeEnsured(alloc)) {
     LLVM_DEBUG(llvm::dbgs() << "*** Deleting store-only AllocStack: "<< *alloc);
     deleter.forceDeleteWithUsers(alloc);
     return true;
diff --git a/lib/SILOptimizer/Transforms/SimplifyCFG.cpp b/lib/SILOptimizer/Transforms/SimplifyCFG.cpp
index 66d23367fd71d..79f0c23048161 100644
--- a/lib/SILOptimizer/Transforms/SimplifyCFG.cpp
+++ b/lib/SILOptimizer/Transforms/SimplifyCFG.cpp
@@ -304,7 +304,8 @@ static SILValue createValueForEdge(SILInstruction *UserInst,
 
   if (auto *CBI = dyn_cast<CondBranchInst>(DominatingTerminator))
     return Builder.createIntegerLiteral(
-        CBI->getLoc(), CBI->getCondition()->getType(), EdgeIdx == 0 ? -1 : 0);
+        CBI->getLoc(), CBI->getCondition()->getType(), EdgeIdx == 0 ? -1 : 0,
+        /*treatAsSigned=*/true);
 
   auto *SEI = cast<SwitchEnumInst>(DominatingTerminator);
   auto *DstBlock = SEI->getSuccessors()[EdgeIdx].getBB();
@@ -1480,7 +1481,8 @@ static SILValue invertExpectAndApplyTo(SILBuilder &Builder,
   if (!IL)
     return V;
   SILValue NegatedExpectedValue = Builder.createIntegerLiteral(
-      IL->getLoc(), Args[1]->getType(), IL->getValue() == 0 ? -1 : 0);
+      IL->getLoc(), Args[1]->getType(), IL->getValue() == 0 ? -1 : 0,
+      /*treatAsSigned=*/true);
   return Builder.createBuiltin(BI->getLoc(), BI->getName(), BI->getType(), {},
                                {V, NegatedExpectedValue});
 }
@@ -3317,6 +3319,12 @@ static bool splitBBArguments(SILFunction &Fn) {
 }
 
 bool SimplifyCFG::run() {
+#ifndef SWIFT_ENABLE_SWIFT_IN_SWIFT
+  // This pass results in verification failures when Swift sources are not
+  // enabled.
+  LLVM_DEBUG(llvm::dbgs() << "SimplifyCFG disabled in C++-only Swift compiler\n");
+  return false;
+#endif //!SWIFT_ENABLE_SWIFT_IN_SWIFT
   LLVM_DEBUG(llvm::dbgs() << "### Run SimplifyCFG on " << Fn.getName() << '\n');
 
   // Disable some expensive optimizations if the function is huge.
diff --git a/lib/SILOptimizer/Transforms/SpeculativeDevirtualizer.cpp b/lib/SILOptimizer/Transforms/SpeculativeDevirtualizer.cpp
index 1f1d5ee0d2b80..a156c5e283527 100644
--- a/lib/SILOptimizer/Transforms/SpeculativeDevirtualizer.cpp
+++ b/lib/SILOptimizer/Transforms/SpeculativeDevirtualizer.cpp
@@ -163,7 +163,7 @@ static FullApplySite speculateMonomorphicTarget(SILPassManager *pm, FullApplySit
   // class instance is identical to the SILType.
 
   CCBI = Builder.createCheckedCastBranch(AI.getLoc(), /*exact*/ true,
-                                      CastingIsolatedConformances::Allow,
+                                      CheckedCastInstOptions(),
                                       CMI->getOperand(),
                                       CMI->getOperand()->getType().getASTType(),
                                       SILType::getPrimitiveObjectType(SubType),
@@ -446,7 +446,7 @@ static bool tryToSpeculateTarget(SILPassManager *pm, FullApplySite AI, ClassHier
 
   // Try to devirtualize the static class of instance
   // if it is possible.
-  if (auto F = getTargetClassMethod(M, CD, ClassType, CMI)) {
+  if (auto F = getTargetClassMethod(M, AI, CD, ClassType, CMI)) {
     // Do not devirtualize if a method in the base class is marked
     // as non-optimizable. This way it is easy to disable the
     // devirtualization of this method in the base class and
diff --git a/lib/SILOptimizer/Transforms/TempLValueOpt.cpp b/lib/SILOptimizer/Transforms/TempLValueOpt.cpp
deleted file mode 100644
index 05b312005c723..0000000000000
--- a/lib/SILOptimizer/Transforms/TempLValueOpt.cpp
+++ /dev/null
@@ -1,361 +0,0 @@
-//===--- TempLValueOpt.cpp - Optimize temporary l-values ------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass optimizes copies from a temporary (an "l-value") to a destination.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "cow-opts"
-
-#include "swift/Basic/Assertions.h"
-#include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Analysis/AliasAnalysis.h"
-#include "swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h"
-#include "swift/SIL/NodeBits.h"
-#include "swift/SIL/SILFunction.h"
-#include "swift/SIL/SILBasicBlock.h"
-#include "swift/SIL/Projection.h"
-#include "swift/SIL/SILBuilder.h"
-#include "llvm/Support/Debug.h"
-
-using namespace swift;
-
-namespace {
-
-/// Optimizes copies from a temporary (an "l-value") to a destination.
-///
-/// \code
-///   %temp = alloc_stack $Ty
-///   instructions_which_store_to %temp
-///   copy_addr [take] %temp to %destination
-///   dealloc_stack %temp
-/// \endcode
-///
-/// is optimized to
-///
-/// \code
-///   destroy_addr %destination
-///   instructions_which_store_to %destination
-/// \endcode
-///
-/// The name TempLValueOpt refers to the TempRValueOpt pass, which performs
-/// a related transformation, just with the temporary on the "right" side.
-///
-/// Note that TempLValueOpt is similar to CopyForwarding::backwardPropagateCopy.
-/// It's more restricted (e.g. the copy-source must be an alloc_stack).
-/// That enables other patterns to be optimized, which backwardPropagateCopy
-/// cannot handle.
-///
-/// The pass also performs a peephole optimization on copy_addr - destroy
-/// sequences.
-/// It replaces
-///
-/// \code
-///   copy_addr %source to %destination
-///   destroy_addr %source
-/// \endcode
-///
-/// with
-///
-/// \code
-///   copy_addr [take] %source to %destination
-/// \endcode
-///
-/// This peephole optimization is also done by the DestroyHoisting pass. But
-/// DestroyHoisting currently only runs on OSSA.
-/// TODO: when DestroyHoisting can run later in the pipeline, check if we still
-///       need this peephole here.
-class TempLValueOptPass : public SILFunctionTransform {
-public:
-  TempLValueOptPass() {}
-
-  void run() override;
-
-private:
-  void tempLValueOpt(CopyAddrInst *copyInst);
-  void combineCopyAndDestroy(CopyAddrInst *copyInst);
-  bool hasInvalidApplyArgumentAliasing(SILInstruction *inst, SILValue tempAddr,
-                                       SILValue destAddr, AliasAnalysis *aa);
-};
-
-void TempLValueOptPass::run() {
-  SILFunction *F = getFunction();
-  if (!F->shouldOptimize())
-    return;
-
-  LLVM_DEBUG(llvm::dbgs() << "*** TempLValueOptPass on function: "
-                          << F->getName() << " ***\n");
-
-  for (SILBasicBlock &block : *F) {
-    // First collect all copy_addr instructions upfront to avoid iterator
-    // invalidation problems (the optimizations might delete the copy_addr
-    // itself or any following instruction).
-    llvm::SmallVector<CopyAddrInst *, 32> copyInsts;
-    for (SILInstruction &inst : block) {
-      if (auto *copyInst = dyn_cast<CopyAddrInst>(&inst))
-        copyInsts.push_back(copyInst);
-    }
-    // Do the optimizations.
-    for (CopyAddrInst *copyInst : copyInsts) {
-      combineCopyAndDestroy(copyInst);
-      tempLValueOpt(copyInst);
-    }
-  }
-}
-
-static SingleValueInstruction *isMovableProjection(SILValue addr) {
-  if (auto *existentialAddr = dyn_cast<InitExistentialAddrInst>(addr))
-    return existentialAddr;
-    
-  if (SingleValueInstruction *svi = Projection::isAddressProjection(addr)) {
-    if (svi->getNumOperands() == 1)
-      return svi;
-  }
-  return nullptr;
-}
-
-void TempLValueOptPass::tempLValueOpt(CopyAddrInst *copyInst) {
-
-  // An overview of the algorithm:
-  //
-  //   alloc_stack %temp
-  //   ...
-  //   first_use_of %temp // beginOfLiverange
-  //   ... // no reads or writes from/to %destination
-  //   copy_addr [take] %temp to %destination // copyInst
-  //   ... // no further uses of %temp (copyInst is the end of %temp liverange)
-  //   dealloc_stack %temp
-  //
-  // All projections to %destination are hoisted above the first use of %temp.
-  // Then all uses of %temp are replaced by %destination.
-  // In case the copyInst is not initializing %destination, a
-  // 'destroy_addr %destination' is inserted before the first use of %temp.
-
-  if (!copyInst->isTakeOfSrc())
-    return;
-
-  auto *temporary = dyn_cast<AllocStackInst>(copyInst->getSrc());
-  if (!temporary)
-    return;
-
-  // Collect all users of the temporary into a set. Also, for simplicity,
-  // require that all users are within a single basic block.
-  InstructionSet users(getFunction());
-  SILBasicBlock *block = temporary->getParent();
-  for (Operand *use : temporary->getUses()) {
-    SILInstruction *user = use->getUser();
-    if (user->getParent() != block)
-      return;
-    users.insert(user);
-  }
-
-  // Collect all address projections of the destination - in case we need to
-  // hoist them.
-  InstructionSet projections(getFunction());
-  SILValue destination = copyInst->getDest();
-  SILValue destRootAddr = destination;
-  while (SingleValueInstruction *projInst = isMovableProjection(destRootAddr)) {
-    // In theory, users of the temporary and address projections of the
-    // destination should be completely distinct. Otherwise the copyInst would
-    // be an identity copy (source == destination).
-    // Just to be on the safe side, bail if it's not the case (instead of an
-    // assert).
-    if (users.contains(projInst))
-      return;
-    projections.insert(projInst);
-    destRootAddr = projInst->getOperand(0);
-  }
-  // The root address of the destination. It's null if it's not an instruction,
-  // but a block argument.
-  SILInstruction *destRootInst = destRootAddr->getDefiningInstruction();
-
-  bool needDestroyEarly = false;
-  BasicCalleeAnalysis *bca = nullptr;
-  if (!copyInst->isInitializationOfDest()) {
-    needDestroyEarly = true;
-    bca = PM->getAnalysis<BasicCalleeAnalysis>();
-  }
-
-  // Iterate over the liverange of the temporary and make some validity checks.
-  AliasAnalysis *AA = nullptr;
-  SILInstruction *beginOfLiverange = nullptr;
-  bool endOfLiverangeReached = false;
-  for (auto iter = temporary->getIterator(); iter != block->end(); ++iter) {
-    SILInstruction *inst = &*iter;
-    // The dealloc_stack is the last user of the temporary.
-    if (isa<DeallocStackInst>(inst) && inst->getOperand(0) == temporary)
-      break;
-
-    if (users.contains(inst) != 0) {
-      // Check if the copyInst is the last user of the temporary (beside the
-      // dealloc_stack).
-      if (endOfLiverangeReached)
-        return;
-
-      // Find the first user of the temporary to get a more precise liverange.
-      // It would be too conservative to treat the alloc_stack itself as the
-      // begin of the liverange.
-      if (!beginOfLiverange)
-        beginOfLiverange = inst;
-
-      if (inst == copyInst)
-        endOfLiverangeReached = true;
-    }
-    if (beginOfLiverange && !endOfLiverangeReached) {
-      // If the root address of the destination is within the liverange of the
-      // temporary, we cannot replace all uses of the temporary with the
-      // destination (it would break the def-use dominance rule).
-      if (inst == destRootInst)
-        return;
-        
-      if (!AA)
-        AA = PM->getAnalysis<AliasAnalysis>(getFunction());
-
-      // Check if the destination is not accessed within the liverange of
-      // the temporary.
-      // This is unlikely, because the destination is initialized at the
-      // copyInst. But still, the destination could contain an initialized value
-      // which is destroyed before the copyInst.
-      if (AA->mayReadOrWriteMemory(inst, destination) &&
-          // Needed to treat init_existential_addr as not-writing projection.
-          projections.contains(inst) == 0)
-        return;
-
-      // Check if replacing the temporary with destination would invalidate an applied
-      // function's alias rules of indirect arguments.
-      if (hasInvalidApplyArgumentAliasing(inst, temporary, destination, AA))
-        return;
-      
-      if (needDestroyEarly && isDeinitBarrier(inst, bca))
-        return;
-    }
-  }
-  assert(endOfLiverangeReached);
-
-  // Move all projections of the destination address before the liverange of
-  // the temporary.
-  for (auto iter = beginOfLiverange->getIterator();
-       iter != copyInst->getIterator();) {
-    SILInstruction *inst = &*iter++;
-    if (projections.contains(inst))
-      inst->moveBefore(beginOfLiverange);
-  }
-
-  if (!copyInst->isInitializationOfDest()) {
-    // Make sure the destination is uninitialized before the liverange of
-    // the temporary.
-    SILBuilderWithScope builder(beginOfLiverange);
-    builder.createDestroyAddr(copyInst->getLoc(), destination);
-  }
-
-  // Replace all uses of the temporary with the destination address.
-  while (!temporary->use_empty()) {
-    Operand *use = *temporary->use_begin();
-    SILInstruction *user = use->getUser();
-    switch (user->getKind()) {
-      case SILInstructionKind::DeallocStackInst:
-        user->eraseFromParent();
-        break;
-      default:
-        use->set(destination);
-    }
-  }
-  temporary->eraseFromParent();
-  copyInst->eraseFromParent();
-  invalidateAnalysis(SILAnalysis::InvalidationKind::Instructions);
-}
-
-/// Returns true if after replacing tempAddr with destAddr an apply instruction
-/// would have invalid aliasing of indirect arguments.
-/// 
-/// An indirect argument (except `@inout_aliasable`) must not alias with another
-/// indirect argument. Now, if we would replace tempAddr with destAddr in
-/// 
-///   apply %f(%tempAddr, %destAddr) : (@in T) -> @out T
-///   
-/// we would invalidate this rule.
-/// This is even true if the called function does not read from destAddr.
-///
-bool TempLValueOptPass::hasInvalidApplyArgumentAliasing(SILInstruction *inst,
-                                                        SILValue tempAddr,
-                                                        SILValue destAddr,
-                                                        AliasAnalysis *aa) {
-  auto as = FullApplySite::isa(inst);
-  if (!as)
-    return false;
-  
-  bool tempAccessed = false;
-  bool destAccessed = false;
-  bool mutatingAccess = false;
-  for (Operand &argOp : as.getArgumentOperands()) {
-    auto conv = as.getArgumentConvention(argOp);
-    if (conv.isExclusiveIndirectParameter()) {
-      if (aa->mayAlias(tempAddr, argOp.get())) {
-        tempAccessed = true;
-        if (!conv.isGuaranteedConventionInCaller())
-          mutatingAccess = true;
-      } else if (aa->mayAlias(destAddr, argOp.get())) {
-        destAccessed = true;
-        if (!conv.isGuaranteedConventionInCaller())
-          mutatingAccess = true;
-      }
-    }
-  }
-  return mutatingAccess && tempAccessed && destAccessed;
-}
-
-void TempLValueOptPass::combineCopyAndDestroy(CopyAddrInst *copyInst) {
-  if (copyInst->isTakeOfSrc())
-    return;
-
-  // Find a destroy_addr of the copy's source address.
-  DestroyAddrInst *destroy = nullptr;
-  for (Operand *srcUse : copyInst->getSrc()->getUses()) {
-    if ((destroy = dyn_cast<DestroyAddrInst>(srcUse->getUser())))
-      break;
-  }
-  SILBasicBlock *block = copyInst->getParent();
-  if (!destroy || destroy->getParent() != block)
-    return;
-  assert(destroy->getOperand() == copyInst->getSrc());
-
-  // Check if the destroy_addr is after the copy_addr and if there are no
-  // memory accesses between them.
-  SmallVector<SILInstruction *, 4> debugInsts;
-  for (auto iter = std::next(copyInst->getIterator());
-       iter != block->end(); ++iter) {
-    SILInstruction *inst = &*iter;
-    if (inst == destroy) {
-      copyInst->setIsTakeOfSrc(IsTake);
-      destroy->eraseFromParent();
-      // Cleanup all debug_value of the copy src btw the copy and destroy
-      for (auto debugInst : debugInsts) {
-        debugInst->eraseFromParent();
-      }
-      invalidateAnalysis(SILAnalysis::InvalidationKind::Instructions);
-      return;
-    }
-    if(auto *debugInst = DebugValueInst::hasAddrVal(inst)) {
-      if (debugInst->getOperand() == copyInst->getSrc())
-        debugInsts.push_back(debugInst);
-    }
-    if (inst->mayReadOrWriteMemory())
-      return;
-  }
-}
-
-} // end anonymous namespace
-
-SILTransform *swift::createTempLValueOpt() {
-  return new TempLValueOptPass();
-}
-
diff --git a/lib/SILOptimizer/Transforms/TempRValueElimination.cpp b/lib/SILOptimizer/Transforms/TempRValueElimination.cpp
deleted file mode 100644
index 33817d731505e..0000000000000
--- a/lib/SILOptimizer/Transforms/TempRValueElimination.cpp
+++ /dev/null
@@ -1,972 +0,0 @@
-//===--- TempRValueElimination.cpp ----------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// Eliminate temporary RValues inserted as a result of materialization by
-/// SILGen. The key pattern here is that we are looking for alloc_stack that are
-/// only written to once and are eventually either destroyed/taken from.
-///
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "sil-temp-rvalue-opt"
-
-#include "swift/Basic/Assertions.h"
-#include "swift/SIL/BasicBlockUtils.h"
-#include "swift/SIL/DebugUtils.h"
-#include "swift/SIL/MemAccessUtils.h"
-#include "swift/SIL/NodeBits.h"
-#include "swift/SIL/OSSALifetimeCompletion.h"
-#include "swift/SIL/OwnershipUtils.h"
-#include "swift/SIL/SILArgument.h"
-#include "swift/SIL/SILBuilder.h"
-#include "swift/SIL/SILVisitor.h"
-#include "swift/SILOptimizer/Analysis/AliasAnalysis.h"
-#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
-#include "swift/SILOptimizer/Analysis/PostOrderAnalysis.h"
-#include "swift/SILOptimizer/Analysis/RCIdentityAnalysis.h"
-#include "swift/SILOptimizer/Analysis/SimplifyInstruction.h"
-#include "swift/SILOptimizer/PassManager/Passes.h"
-#include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CFGOptUtils.h"
-#include "swift/SILOptimizer/Utils/ValueLifetime.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Debug.h"
-
-using namespace swift;
-
-//===----------------------------------------------------------------------===//
-//                                 Interface
-//===----------------------------------------------------------------------===//
-
-namespace {
-
-/// Temporary RValue Optimization
-///
-/// Peephole optimization to eliminate short-lived immutable temporary copies.
-/// This handles a common pattern generated by SILGen where temporary RValues
-/// are emitted as copies...
-///
-///   %temp = alloc_stack $T
-///   copy_addr %src to [init] %temp : $*T
-///   // no writes to %src or %temp
-///   destroy_addr %temp : $*T
-///   dealloc_stack %temp : $*T
-///
-/// This differs from the copy forwarding algorithm because it handles
-/// copy source and dest lifetimes that are unavoidably overlapping. Instead,
-/// it finds cases in which it is easy to determine that the source is
-/// unmodified during the copy destination's lifetime. Thus, the destination can
-/// be viewed as a short-lived "rvalue".
-///
-/// As a second optimization, also stores into temporaries are handled. This is
-/// a simple form of redundant-load-elimination (RLE).
-///
-///   %temp = alloc_stack $T
-///   store %src to [init] %temp : $*T
-///   // no writes to %temp
-///   %v = load [take] %temp : $*T
-///   dealloc_stack %temp : $*T
-///
-/// TODO: Check if we still need to handle stores when RLE supports OSSA.
-class TempRValueOptPass : public SILFunctionTransform {
-  bool collectLoads(Operand *addressUse, CopyAddrInst *originalCopy,
-                    InstructionSetWithSize &loadInsts);
-  bool collectLoadsFromProjection(SingleValueInstruction *projection,
-                                  CopyAddrInst *originalCopy,
-                                  InstructionSetWithSize &loadInsts);
-
-  SILInstruction *getLastUseWhileSourceIsNotModified(
-    CopyAddrInst *copyInst, const InstructionSetWithSize &useInsts,
-    AliasAnalysis *aa);
-
-  bool
-  checkTempObjectDestroy(AllocStackInst *tempObj, CopyAddrInst *copyInst);
-
-  bool extendAccessScopes(CopyAddrInst *copyInst, SILInstruction *lastUseInst,
-                          AliasAnalysis *aa);
-
-  void tryOptimizeCopyIntoTemp(CopyAddrInst *copyInst);
-  SILBasicBlock::iterator tryOptimizeStoreIntoTemp(StoreInst *si);
-
-  void run() override;
-};
-
-} // anonymous namespace
-
-bool TempRValueOptPass::collectLoadsFromProjection(
-    SingleValueInstruction *projection, CopyAddrInst *originalCopy,
-    InstructionSetWithSize &loadInsts) {
-  // Transitively look through projections on stack addresses.
-  for (auto *projUseOper : projection->getUses()) {
-    auto *user = projUseOper->getUser();
-    if (user->isTypeDependentOperand(*projUseOper))
-      continue;
-
-    if (!collectLoads(projUseOper, originalCopy, loadInsts))
-      return false;
-  }
-  return true;
-}
-
-/// Transitively explore all data flow uses of the given \p address until
-/// reaching a load or returning false.
-///
-/// Any user opcode recognized by collectLoads must be replaced correctly later
-/// during tryOptimizeCopyIntoTemp. If it is possible for any use to destroy the
-/// value in \p address, then that use must be removed or made non-destructive
-/// after the copy is removed and its operand is replaced.
-///
-/// Warning: To preserve the original object lifetime, tryOptimizeCopyIntoTemp
-/// must assume that there are no holes in lifetime of the temporary stack
-/// location at \address. The temporary must be initialized by the original copy
-/// and never written to again. Therefore, collectLoads disallows any operation
-/// that may write to memory at \p address.
-bool TempRValueOptPass::
-collectLoads(Operand *addressUse, CopyAddrInst *originalCopy,
-             InstructionSetWithSize &loadInsts) {
-  SILInstruction *user = addressUse->getUser();
-  SILValue address = addressUse->get();
-
-  // All normal uses (loads) must be in the initialization block.
-  // (The destroy and dealloc are commonly in a different block though.)
-  SILBasicBlock *block = originalCopy->getParent();
-  if (user->getParent() != block)
-    return false;
-
-  // Only allow uses that cannot destroy their operand. We need to be sure
-  // that replacing all this temporary's uses with the copy source doesn't
-  // destroy the source. This way, we know that the destroy_addr instructions
-  // that we recorded cover all the temporary's lifetime termination points.
-  //
-  // Currently this includes address projections, loads, and in_guaranteed uses
-  // by an apply.
-  //
-  // TODO: handle non-destructive projections of enums
-  // (unchecked_take_enum_data_addr of Optional is nondestructive.)
-  switch (user->getKind()) {
-  default:
-    LLVM_DEBUG(llvm::dbgs()
-               << "  Temp use may write/destroy its source" << *user);
-    return false;
-  case SILInstructionKind::BeginAccessInst: {
-    auto *beginAccess = cast<BeginAccessInst>(user);
-    if (beginAccess->getAccessKind() != SILAccessKind::Read)
-      return false;
-
-    // We don't have to recursively call collectLoads for the beginAccess
-    // result, because a SILAccessKind::Read already guarantees that there are
-    // no writes to the beginAccess result address (or any projection from it).
-    // But we have to register the end-accesses as loads to correctly mark the
-    // end-of-lifetime of the tempObj.
-    //
-    //   %addr = begin_access [read]
-    //      ... // there can be no writes to %addr here
-    //   end_access %addr   // <- This is where the use actually ends.
-    for (EndAccessInst *endAccess : beginAccess->getEndAccesses()) {
-      if (endAccess->getParent() != block)
-        return false;
-      loadInsts.insert(endAccess);
-    }
-    return true;
-  }
-  case SILInstructionKind::MarkDependenceInst: {
-    auto mdi = cast<MarkDependenceInst>(user);
-    if (mdi->getBase() == address) {
-      // We want to keep the original lifetime of the base. If we would eliminate
-      // the base alloc_stack, we risk to insert a destroy_addr too early.
-      return false;
-    }
-    // If the user is the value operand of the MarkDependenceInst we have to
-    // transitively explore its uses until we reach a load or return false
-    for (auto *mdiUseOper : mdi->getUses()) {
-      if (!collectLoads(mdiUseOper, originalCopy, loadInsts))
-        return false;
-    }
-    return true;
-  }
-  case SILInstructionKind::PartialApplyInst:
-    if (!cast<PartialApplyInst>(user)->isOnStack())
-      return false;
-     LLVM_FALLTHROUGH;
-  case SILInstructionKind::ApplyInst:
-  case SILInstructionKind::TryApplyInst:
-  case SILInstructionKind::BeginApplyInst: {
-    auto convention = ApplySite(user).getArgumentConvention(*addressUse);
-    if (!convention.isGuaranteedConventionInCaller())
-      return false;
-
-    loadInsts.insert(user);
-    if (auto *beginApply = dyn_cast<BeginApplyInst>(user)) {
-      // Register 'end_apply'/'abort_apply' as loads as well
-      // 'checkNoSourceModification' should check instructions until
-      // 'end_apply'/'abort_apply'.
-      for (auto *tokenUse : beginApply->getEndApplyUses()) {
-        auto *tokenUser = tokenUse->getUser();
-        if (tokenUser->getParent() != block)
-          return false;
-        loadInsts.insert(tokenUser);
-      }
-    }
-    return true;
-  }
-  case SILInstructionKind::YieldInst: {
-    auto *yield = cast<YieldInst>(user);
-    auto convention = yield->getArgumentConventionForOperand(*addressUse);
-    if (!convention.isGuaranteedConventionInCaller())
-      return false;
-
-    loadInsts.insert(user);
-    return true;
-  }
-  case SILInstructionKind::OpenExistentialAddrInst: {
-    // We only support open existential addr if the access is immutable.
-    auto *oeai = cast<OpenExistentialAddrInst>(user);
-    if (oeai->getAccessKind() != OpenedExistentialAccess::Immutable) {
-      LLVM_DEBUG(llvm::dbgs() << "  Temp consuming use may write/destroy "
-                                 "its source"
-                              << *user);
-      return false;
-    }
-    return collectLoadsFromProjection(oeai, originalCopy, loadInsts);
-  }
-  case SILInstructionKind::UncheckedTakeEnumDataAddrInst: {
-    // In certain cases, unchecked_take_enum_data_addr invalidates the
-    // underlying memory, so by default we can not look through it... but this
-    // is not true in the case of Optional. This is an important case for us to
-    // handle, so handle it here.
-    auto *utedai = cast<UncheckedTakeEnumDataAddrInst>(user);
-    if (!utedai->getOperand()->getType().getOptionalObjectType()) {
-      LLVM_DEBUG(llvm::dbgs()
-                 << "  Temp use may write/destroy its source" << *utedai);
-      return false;
-    }
-
-    return collectLoadsFromProjection(utedai, originalCopy, loadInsts);
-  }
-  case SILInstructionKind::StructElementAddrInst:
-  case SILInstructionKind::TupleElementAddrInst:
-  case SILInstructionKind::UncheckedAddrCastInst:
-    return collectLoadsFromProjection(cast<SingleValueInstruction>(user),
-                                      originalCopy, loadInsts);
-
-  case SILInstructionKind::LoadInst: {
-    // Loads are the end of the data flow chain. The users of the load can't
-    // access the temporary storage.
-    //
-    // That being said, if we see a load [take] here then we must have had a
-    // load [take] of a projection of our temporary stack location since we skip
-    // all the load [take] of the top level allocation in the caller of this
-    // function. So if we have such a load [take], we /must/ have a
-    // reinitialization or an alloc_stack that does not fit the pattern we are
-    // expecting from SILGen. Be conservative and return false.
-    auto *li = cast<LoadInst>(user);
-    if (li->getOwnershipQualifier() == LoadOwnershipQualifier::Take &&
-        // Only accept load [take] if it takes the whole temporary object.
-        // load [take] from a projection would destroy only a part of the
-        // temporary and we don't handle this.
-        address != originalCopy->getDest()) {
-      return false;
-    }
-    loadInsts.insert(user);
-    return true;
-  }
-  case SILInstructionKind::LoadBorrowInst: {
-    loadInsts.insert(user);
-    BorrowedValue borrow(cast<LoadBorrowInst>(user));
-    auto visitEndScope = [&](Operand *op) -> bool {
-      auto *opUser = op->getUser();
-      if (auto *endBorrow = dyn_cast<EndBorrowInst>(opUser)) {
-        if (endBorrow->getParent() != block)
-          return false;
-        loadInsts.insert(endBorrow);
-        return true;
-      }
-      // Don't look further if we see a reborrow.
-      assert(cast<BranchInst>(opUser));
-      return false;
-    };
-    auto res = borrow.visitLocalScopeEndingUses(visitEndScope);
-    return res;
-  }
-  case SILInstructionKind::FixLifetimeInst:
-    // If we have a fixed lifetime on our alloc_stack, we can just treat it like
-    // a load and re-write it so that it is on the old memory or old src object.
-    loadInsts.insert(user);
-    return true;
-  case SILInstructionKind::CopyAddrInst: {
-    // copy_addr which read from the temporary are like loads.
-    auto *copyFromTmp = cast<CopyAddrInst>(user);
-    if (copyFromTmp->getDest() == address) {
-      LLVM_DEBUG(llvm::dbgs() << "  Temp written or taken" << *user);
-      return false;
-    }
-    // As with load [take], only accept copy_addr [take] if it takes the whole
-    // temporary object.
-    if (copyFromTmp->isTakeOfSrc() && address != originalCopy->getDest())
-      return false;
-    loadInsts.insert(copyFromTmp);
-    return true;
-  }
-  }
-}
-
-/// Checks if the source of \p copyInst is not modified within the temporary's
-/// lifetime, i.e. is not modified before the last use of \p useInsts.
-///
-/// If there are no source modifications with the lifetime, returns the last
-/// user (or copyInst if there are no uses at all).
-/// Otherwise, returns a nullptr.
-///
-/// Unfortunately, we cannot simply use the destroy points as the lifetime end,
-/// because they can be in a different basic block (that's what SILGen
-/// generates). Instead we guarantee that all normal uses are within the block
-/// of the temporary and look for the last use, which effectively ends the
-/// lifetime.
-SILInstruction *TempRValueOptPass::getLastUseWhileSourceIsNotModified(
-    CopyAddrInst *copyInst, const InstructionSetWithSize &useInsts,
-    AliasAnalysis *aa) {
-  if (useInsts.empty())
-    return copyInst;
-  unsigned numLoadsFound = 0;
-  SILValue copySrc = copyInst->getSrc();
-
-  // We already checked that the useful lifetime of the temporary ends in
-  // the initialization block. Iterate over the instructions of the block,
-  // starting at copyInst, until we get to the last user.
-  auto iter = std::next(copyInst->getIterator());
-  auto iterEnd = copyInst->getParent()->end();
-  for (; iter != iterEnd; ++iter) {
-    SILInstruction *inst = &*iter;
-
-    if (useInsts.contains(inst))
-      ++numLoadsFound;
-
-    // If this is the last use of the temp we are ok. After this point,
-    // modifications to the source don't matter anymore.
-    // Note that we are assuming here that if an instruction loads and writes
-    // to copySrc at the same time (like a copy_addr could do), the write
-    // takes effect after the load.
-    if (numLoadsFound == useInsts.size()) {
-      // Function calls are an exception: in a called function a potential
-      // modification of copySrc could occur _before_ the read of the temporary.
-      if ((FullApplySite::isa(inst) || isa<YieldInst>(inst)) &&
-          aa->mayWriteToMemory(inst, copySrc)) {
-        return nullptr;
-      }
-
-      return inst;
-    }
-
-    if (aa->mayWriteToMemory(inst, copySrc)) {
-      LLVM_DEBUG(llvm::dbgs() << "  Source modified by" << *iter);
-      return nullptr;
-    }
-  }
-  // For some reason, not all normal uses have been seen between the copy and
-  // the end of the initialization block. We should never reach here.
-  return nullptr;
-}
-
-/// Tries to move an end_access down to extend the access scope over all uses
-/// of the temporary. For example:
-///
-///   %a = begin_access %src
-///   copy_addr %a to [init] %temp : $*T
-///   end_access %a
-///   use %temp
-///
-/// We must not replace %temp with %a after the end_access. Instead we try to
-/// move the end_access after "use %temp".
-bool TempRValueOptPass::extendAccessScopes(
-    CopyAddrInst *copyInst, SILInstruction *lastUseInst, AliasAnalysis *aa) {
-
-  SILValue copySrc = copyInst->getSrc();
-  EndAccessInst *endAccessToMove = nullptr;
-  auto begin = std::next(copyInst->getIterator());
-  auto end = std::next(lastUseInst->getIterator());
-
-  for (SILInstruction &inst : make_range(begin, end)) {
-    if (auto *endAccess = dyn_cast<EndAccessInst>(&inst)) {
-      // To keep things simple, we can just move a single end_access. Also, we
-      // cannot move an end_access over a (non-aliasing) end_access.
-      if (endAccessToMove)
-        return false;
-      // Is this the end of an access scope of the copy-source?
-      if (aa->mayAlias(copySrc, endAccess->getSource()) &&
-
-          // There cannot be any aliasing modifying accesses within the
-          // liverange of the temporary, because we would have cought this in
-          // `getLastUseWhileSourceIsNotModified`.
-          // But there are cases where `AliasAnalysis::isNoAlias` is less
-          // precise than `AliasAnalysis::mayWriteToMemory`. Therefore, just
-          // ignore any non-read accesses.
-          endAccess->getBeginAccess()->getAccessKind() == SILAccessKind::Read) {
-
-        // Don't move instructions beyond the block's terminator.
-        if (isa<TermInst>(lastUseInst))
-          return false;
-
-        endAccessToMove = endAccess;
-      }
-    } else if (endAccessToMove) {
-      // We cannot move an end_access over a begin_access. This would destroy
-      // the proper nesting of accesses.
-      if (isa<BeginAccessInst>(&inst) || isa<BeginUnpairedAccessInst>(inst))
-        return false;
-      // Don't extend a read-access scope over a (potential) write.
-      // Note that inst can be a function call containing other access scopes.
-      // But doing the mayWriteToMemory check, we know that the function can
-      // only contain read accesses (to the same memory location). So it's fine
-      // to move endAccessToMove even over such a function call.
-      if (aa->mayWriteToMemory(&inst, endAccessToMove->getSource()))
-        return false;
-    }
-  }
-  if (endAccessToMove)
-    endAccessToMove->moveAfter(lastUseInst);
-
-  return true;
-}
-
-/// Return true if the \p tempObj, which is initialized by \p copyInst, is
-/// destroyed in an orthodox way.
-///
-/// When tryOptimizeCopyIntoTemp replaces all of tempObj's uses, it assumes that
-/// the object is initialized by the original copy and directly destroyed on all
-/// paths by one of the recognized 'destroy_addr' or 'copy_addr [take]'
-/// operations. This assumption must be checked. For example, in non-OSSA,
-/// it is legal to destroy an in-memory object by loading the value and
-/// releasing it. Rather than detecting unbalanced load releases, simply check
-/// that tempObj is destroyed directly on all paths.
-bool TempRValueOptPass::checkTempObjectDestroy(
-    AllocStackInst *tempObj, CopyAddrInst *copyInst) {
-  // ValueLifetimeAnalysis is not normally used for address types. It does not
-  // reason about the lifetime of the in-memory object. However the utility can
-  // be abused here to check that the address is directly destroyed on all
-  // paths. collectLoads has already guaranteed that tempObj's lifetime has no
-  // holes/reinitializations.
-  SmallVector<SILInstruction *, 8> users;
-  for (auto result : tempObj->getResults()) {
-    for (Operand *operand : result->getUses()) {
-      SILInstruction *user = operand->getUser();
-      if (user == copyInst)
-        continue;
-      if (isa<DeallocStackInst>(user))
-        continue;
-      users.push_back(user);
-    }
-  }
-  // Find the boundary of tempObj's address lifetime, starting at copyInst.
-  ValueLifetimeAnalysis vla(copyInst, users);
-  ValueLifetimeAnalysis::Frontier tempAddressFrontier;
-  if (!vla.computeFrontier(tempAddressFrontier,
-                           ValueLifetimeAnalysis::DontModifyCFG)) {
-    return false;
-  }
-  // Check that the lifetime boundary ends at direct destroy points.
-  for (SILInstruction *frontierInst : tempAddressFrontier) {
-    auto pos = frontierInst->getIterator();
-    // If the frontier is at the head of a block, then either it is an
-    // unexpected lifetime exit, or the lifetime ended at a
-    // terminator. TempRValueOptPass does not handle either case.
-    if (pos == frontierInst->getParent()->begin())
-      return false;
-
-    // Look for a known destroy point as described in the function level
-    // comment. This allowlist can be expanded as more cases are handled in
-    // tryOptimizeCopyIntoTemp during copy replacement.
-    SILInstruction *lastUser = &*std::prev(pos);
-    if (isa<DestroyAddrInst>(lastUser))
-      continue;
-
-    if (auto *cai = dyn_cast<CopyAddrInst>(lastUser)) {
-      assert(cai->getSrc() == tempObj && "collectLoads checks for writes");
-      if (cai->isTakeOfSrc())
-        continue;
-    }
-    return false;
-  }
-  return true;
-}
-
-/// Tries to perform the temporary rvalue copy elimination for \p copyInst
-void TempRValueOptPass::tryOptimizeCopyIntoTemp(CopyAddrInst *copyInst) {
-  if (!copyInst->isInitializationOfDest())
-    return;
-
-  auto *tempObj = dyn_cast<AllocStackInst>(copyInst->getDest());
-  if (!tempObj)
-    return;
-
-  // If the temporary storage is lexical, it either came from a source-level var
-  // or was marked lexical because it was passed to a function that has been
-  // inlined.
-  // TODO: [begin_borrow_addr] Once we can mark addresses as being borrowed, we
-  //       won't need to mark alloc_stacks lexical during inlining.  At that
-  //       point, the above comment should change, but the implementation
-  //       remains the same.
-  //
-  // In either case, we can eliminate the temporary if the source of the copy is
-  // lexical and it is live for longer than the temporary.
-  if (tempObj->isLexical()) {
-    // TODO: Determine whether the base of the copy_addr's source is lexical and
-    //       its live range contains the range in which the alloc_stack
-    //       contains the value copied into it via the copy_addr.
-    //
-    // For now, only look for guaranteed arguments.
-    auto storage = AccessStorageWithBase::compute(copyInst->getSrc());
-    if (!storage.base)
-      return;
-    if (auto *arg = dyn_cast<SILFunctionArgument>(storage.base))
-      if (!arg->getArgumentConvention().isGuaranteedConventionInCallee())
-        return;
-  }
-
-  bool isOSSA = copyInst->getFunction()->hasOwnership();
-  
-  SILValue copySrc = copyInst->getSrc();
-  assert(tempObj != copySrc && "can't initialize temporary with itself");
-
-  // If the source of the copyInst is taken, it must be deinitialized (via
-  // destroy_addr, load [take], copy_addr [take]).  This must be done at the
-  // right spot: after the last use tempObj, but before any (potential)
-  // re-initialization of the source.
-  bool needFinalDeinit = copyInst->isTakeOfSrc();
-
-  // Scan all uses of the temporary storage (tempObj) to verify they all refer
-  // to the value initialized by this copy. It is sufficient to check that the
-  // only users that modify memory are the copy_addr [initialization] and
-  // destroy_addr.
-  InstructionSetWithSize loadInsts(getFunction());
-  // Set of tempObj users
-  InstructionSet userSet(getFunction());
-  for (auto *useOper : tempObj->getUses()) {
-    SILInstruction *user = useOper->getUser();
-
-    userSet.insert(user);
-
-    if (user == copyInst)
-      continue;
-
-    // Deallocations are allowed to be in a different block.
-    if (isa<DeallocStackInst>(user))
-      continue;
-
-    // Also, destroys are allowed to be in a different block.
-    if (isa<DestroyAddrInst>(user)) {
-      if (!isOSSA && needFinalDeinit) {
-        // In non-OSSA mode, for the purpose of inserting the destroy of
-        // copySrc, we have to be conservative and assume that the lifetime of
-        // tempObj goes beyond it's last use - until the final destroy_addr.
-        // Otherwise we would risk of inserting the destroy too early.
-        // So we just treat the destroy_addr as any other use of tempObj.
-        if (user->getParent() != copyInst->getParent())
-          return;
-        loadInsts.insert(user);
-      }
-      continue;
-    }
-
-    if (!collectLoads(useOper, copyInst, loadInsts))
-      return;
-  }
-
-  // Check and return without optimization if we have any users of tempObj that
-  // precede the copyInst.
-  // This can happen with projections.
-  // TODO: We can enable this case if we clone the projections at "load" uses
-
-  // All instructions in userSet are in the same block as copyInst. collectLoads
-  // ensures of this.
-  for (SILInstruction &inst : llvm::make_range(copyInst->getParent()->begin(),
-                                               copyInst->getIterator())) {
-    if (userSet.contains(&inst)) {
-      return;
-    }
-  }
-
-  AliasAnalysis *aa = getPassManager()->getAnalysis<AliasAnalysis>(getFunction());
-
-  // Check if the source is modified within the lifetime of the temporary.
-  SILInstruction *lastLoadInst =
-    getLastUseWhileSourceIsNotModified(copyInst, loadInsts, aa);
-  if (!lastLoadInst)
-    return;
-
-  // We cannot insert the destroy of copySrc after lastLoadInst if copySrc is
-  // re-initialized by exactly this instruction.
-  // This is a corner case, but can happen if lastLoadInst is a copy_addr.
-  // Example:
-  //   copy_addr [take] %copySrc to [init] %tempObj   // copyInst
-  //   copy_addr [take] %tempObj to [init] %copySrc   // lastLoadInst
-  if (needFinalDeinit && lastLoadInst != copyInst &&
-      !isa<DestroyAddrInst>(lastLoadInst) &&
-      aa->mayWriteToMemory(lastLoadInst, copySrc))
-    return;
-
-  if (!isOSSA && !checkTempObjectDestroy(tempObj, copyInst))
-    return;
-
-  if (!extendAccessScopes(copyInst, lastLoadInst, aa))
-    return;
-
-  LLVM_DEBUG(llvm::dbgs() << "  Success: replace temp" << *tempObj);
-
-  // If copyInst's source must be deinitialized, whether that must be done via
-  // a newly created destroy_addr.
-  //
-  // If lastLoadInst is a load or a copy_addr, then the deinitialization can be
-  // done in that instruction.
-  //
-  // This is necessary for correctness: otherwise, copies of move-only values
-  // would be introduced.
-  bool needToInsertDestroy = [&]() {
-    if (!needFinalDeinit)
-      return false;
-    if (lastLoadInst == copyInst)
-      return true;
-    if (auto *cai = dyn_cast<CopyAddrInst>(lastLoadInst)) {
-      if (cai->getSrc() == tempObj && cai->isTakeOfSrc()) {
-        // This copy_addr [take] will perform the final deinitialization.
-        return false;
-      }
-      return true;
-    }
-    if (auto *li = dyn_cast<LoadInst>(lastLoadInst)) {
-      if (li->getOperand() == tempObj &&
-          li->getOwnershipQualifier() == LoadOwnershipQualifier::Take) {
-        // This load [take] will perform the final deinitialization.
-        return false;
-      }
-      return true;
-    }
-    return true;
-  }();
-  if (needToInsertDestroy) {
-    // Compensate the [take] of the original copyInst.
-    SILBuilderWithScope::insertAfter(lastLoadInst, [&] (SILBuilder &builder) {
-      builder.createDestroyAddr(builder.getInsertionPoint()->getLoc(), copySrc);
-    });
-  }
-
-  // * Replace all uses of the tempObj with the copySrc.
-  //
-  // * Delete the destroy(s) of tempObj (to compensate the removal of the
-  //   original copyInst): either by erasing the destroy_addr or by converting
-  //   load/copy_addr [take] into copying instructions.
-  //
-  // Note: we must not delete the original copyInst because it would crash the
-  // instruction iteration in run(). Instead the copyInst gets identical Src and
-  // Dest operands.
-  while (!tempObj->use_empty()) {
-    Operand *use = *tempObj->use_begin();
-    SILInstruction *user = use->getUser();
-
-    switch (user->getKind()) {
-    case SILInstructionKind::DestroyAddrInst:
-    case SILInstructionKind::DeallocStackInst:
-      user->eraseFromParent();
-      break;
-    case SILInstructionKind::CopyAddrInst: {
-      auto *cai = cast<CopyAddrInst>(user);
-      if (cai != copyInst) {
-        assert(cai->getSrc() == tempObj);
-        if (cai->isTakeOfSrc() && (!needFinalDeinit || lastLoadInst != cai)) {
-          cai->setIsTakeOfSrc(IsNotTake);
-        }
-      }
-      use->set(copySrc);
-      break;
-    }
-    case SILInstructionKind::LoadInst: {
-      auto *li = cast<LoadInst>(user);
-      if (li->getOwnershipQualifier() == LoadOwnershipQualifier::Take &&
-          (!needFinalDeinit || li != lastLoadInst)) {
-        li->setOwnershipQualifier(LoadOwnershipQualifier::Copy);
-      }
-      use->set(copySrc);
-      break;
-    }
-
-    // ASSUMPTION: no operations that may be handled by this default clause can
-    // destroy tempObj. This includes operations that load the value from memory
-    // and release it or cast the address before destroying it.
-    default:
-      use->set(copySrc);
-      break;
-    }
-  }
-
-  tempObj->eraseFromParent();
-  invalidateAnalysis(SILAnalysis::InvalidationKind::Instructions);
-}
-
-SILBasicBlock::iterator
-TempRValueOptPass::tryOptimizeStoreIntoTemp(StoreInst *si) {
-  // If our store is an assign, bail.
-  if (si->getOwnershipQualifier() == StoreOwnershipQualifier::Assign)
-    return std::next(si->getIterator());
-
-  auto *tempObj = dyn_cast<AllocStackInst>(si->getDest());
-  if (!tempObj) {
-    return std::next(si->getIterator());
-  }
-
-  // If the temporary storage is lexical, it either came from a source-level var
-  // or was marked lexical because it was passed to a function that has been
-  // inlined.
-  // TODO: [begin_borrow_addr] Once we can mark addresses as being borrowed, we
-  //       won't need to mark alloc_stacks lexical during inlining.  At that
-  //       point, the above comment should change, but the implementation
-  //       remains the same.
-  //
-  // In either case, we can eliminate the temporary if the source of the store
-  // is lexical and it is live for longer than the temporary.
-  if (tempObj->isLexical()) {
-    // TODO: Find the lexical root of the source, if any, and allow optimization
-    //       if its live range contains the range in which the alloc_stack
-    //       contains the value stored into it.
-    return std::next(si->getIterator());
-  }
-
-  // If our tempObj has a dynamic lifetime (meaning it is conditionally
-  // initialized, conditionally taken, etc), we can not convert its uses to SSA
-  // while eliminating it simply. So bail.
-  if (tempObj->hasDynamicLifetime()) {
-    return std::next(si->getIterator());
-  }
-
-  // Scan all uses of the temporary storage (tempObj) to verify they all refer
-  // to the value initialized by this copy. It is sufficient to check that the
-  // only users that modify memory are the copy_addr [initialization] and
-  // destroy_addr.
-  for (auto *useOper : tempObj->getUses()) {
-    SILInstruction *user = useOper->getUser();
-
-    if (user == si)
-      continue;
-
-    // Bail if there is any kind of user which is not handled in the code below.
-    switch (user->getKind()) {
-      case SILInstructionKind::DestroyAddrInst:
-      case SILInstructionKind::DeallocStackInst:
-      case SILInstructionKind::LoadInst:
-      case SILInstructionKind::FixLifetimeInst:
-        break;
-      case SILInstructionKind::CopyAddrInst:
-        if (cast<CopyAddrInst>(user)->getDest() == tempObj)
-          return std::next(si->getIterator());
-        break;
-      case SILInstructionKind::MarkDependenceInst:
-        if (cast<MarkDependenceInst>(user)->getValue() == tempObj)
-          return std::next(si->getIterator());
-        break;
-      default:
-        return std::next(si->getIterator());
-    }
-  }
-
-  // Since store is always a consuming operation, we do not need to worry about
-  // any lifetime constraints and can just replace all of the uses here. This
-  // contrasts with the copy_addr implementation where we need to consider the
-  // possibility that the source address is written to.
-  LLVM_DEBUG(llvm::dbgs() << "  Success: replace temp" << *tempObj);
-
-  // Do a "replaceAllUses" by either deleting the users or replacing them with
-  // the appropriate operation on the source value.
-  SmallVector<SILInstruction *, 4> toDelete;
-  for (auto *use : tempObj->getUses()) {
-    // If our store is the user, just skip it.
-    if (use->getUser() == si) {
-      continue;
-    }
-
-    SILInstruction *user = use->getUser();
-    switch (user->getKind()) {
-    case SILInstructionKind::DestroyAddrInst: {
-      SILBuilderWithScope builder(user);
-      builder.emitDestroyValueOperation(user->getLoc(), si->getSrc());
-      toDelete.push_back(user);
-      break;
-    }
-    case SILInstructionKind::DeallocStackInst:
-      toDelete.push_back(user);
-      break;
-    case SILInstructionKind::CopyAddrInst: {
-      auto *cai = cast<CopyAddrInst>(user);
-      assert(cai->getSrc() == tempObj);
-      SILBuilderWithScope builder(user);
-      auto qualifier = cai->isInitializationOfDest()
-                           ? StoreOwnershipQualifier::Init
-                           : StoreOwnershipQualifier::Assign;
-      SILValue src = si->getSrc();
-      if (!cai->isTakeOfSrc()) {
-        src = builder.emitCopyValueOperation(cai->getLoc(), src);
-      }
-      builder.emitStoreValueOperation(cai->getLoc(), src, cai->getDest(),
-                                      qualifier);
-      toDelete.push_back(cai);
-      break;
-    }
-    case SILInstructionKind::LoadInst: {
-      // Since store is always forwarding, we know that we should have our own
-      // value here. So, we should be able to just RAUW any load [take] and
-      // insert a copy + RAUW for any load [copy].
-      auto *li = cast<LoadInst>(user);
-      SILValue srcObject = si->getSrc();
-      if (li->getOwnershipQualifier() == LoadOwnershipQualifier::Copy) {
-        SILBuilderWithScope builder(li);
-        srcObject = builder.emitCopyValueOperation(li->getLoc(), srcObject);
-      }
-      li->replaceAllUsesWith(srcObject);
-      toDelete.push_back(li);
-      break;
-    }
-    case SILInstructionKind::FixLifetimeInst: {
-      auto *fli = cast<FixLifetimeInst>(user);
-      SILBuilderWithScope builder(fli);
-      builder.createFixLifetime(fli->getLoc(), si->getSrc());
-      toDelete.push_back(fli);
-      break;
-    }
-    case SILInstructionKind::MarkDependenceInst: {
-      auto mdi = cast<MarkDependenceInst>(user);
-      assert(mdi->getBase() == tempObj);
-      SILBuilderWithScope builder(user);
-      auto newInst = builder.createMarkDependence(user->getLoc(),
-                                                  mdi->getValue(),
-                                                  si->getSrc(),
-                                                  mdi->dependenceKind());
-      mdi->replaceAllUsesWith(newInst);
-      toDelete.push_back(mdi);
-      break;
-    }
-    // ASSUMPTION: no operations that may be handled by this default clause can
-    // destroy tempObj. This includes operations that load the value from memory
-    // and release it.
-    default:
-      llvm::errs() << "Unhandled user: " << *user;
-      llvm_unreachable("Unhandled case?!");
-      break;
-    }
-  }
-
-  while (!toDelete.empty()) {
-    auto *inst = toDelete.pop_back_val();
-    inst->dropAllReferences();
-    inst->eraseFromParent();
-  }
-  auto nextIter = std::next(si->getIterator());
-  si->eraseFromParent();
-  tempObj->eraseFromParent();
-  invalidateAnalysis(SILAnalysis::InvalidationKind::Instructions);
-
-  return nextIter;
-}
-
-//===----------------------------------------------------------------------===//
-//                           High Level Entrypoint
-//===----------------------------------------------------------------------===//
-
-/// The main entry point of the pass.
-void TempRValueOptPass::run() {
-  auto *function = getFunction();
-
-  auto *da = PM->getAnalysis<DominanceAnalysis>();
-
-  LLVM_DEBUG(llvm::dbgs() << "Copy Peephole in Func " << function->getName()
-                          << "\n");
-
-  SmallVector<SILValue> valuesToComplete;
-
-  // Find all copy_addr instructions.
-  llvm::SmallSetVector<CopyAddrInst *, 8> deadCopies;
-
-  for (auto &block : *function) {
-    // Increment the instruction iterator only after calling
-    // tryOptimizeCopyIntoTemp because the instruction after CopyInst might be
-    // deleted, but copyInst itself won't be deleted until later.
-    for (auto ii = block.begin(); ii != block.end();) {
-      if (auto *copyInst = dyn_cast<CopyAddrInst>(&*ii)) {
-        // In case of success, this may delete instructions, but not the
-        // CopyInst itself.
-        tryOptimizeCopyIntoTemp(copyInst);
-        // Remove identity copies which either directly result from successfully
-        // calling tryOptimizeCopyIntoTemp or was created by an earlier
-        // iteration, where another copy_addr copied the temporary back to the
-        // source location.
-        if (copyInst->getSrc() == copyInst->getDest()) {
-          deadCopies.insert(copyInst);
-        }
-        ++ii;
-        continue;
-      }
-
-      if (auto *si = dyn_cast<StoreInst>(&*ii)) {
-        auto stored = si->getSrc();
-        bool isOrHasEnum = stored->getType().isOrHasEnum();
-        auto nextIter = std::next(si->getIterator());
-
-        ii = tryOptimizeStoreIntoTemp(si);
-
-        // If the optimization was successful, and the stack loc was an enum
-        // type, collect the stored value for lifetime completion.
-        // This is needed because we can have incomplete address lifetimes on
-        // none/trivial paths for an enum type. Once we convert to value form,
-        // this will cause incomplete value lifetimes which can raise ownership
-        // verification errors, because we rely on linear lifetimes in OSSA.
-        if (ii == nextIter && isOrHasEnum) {
-          valuesToComplete.push_back(stored);
-        }
-        continue;
-      }
-
-      ++ii;
-    }
-  }
-
-  auto callbacks = InstModCallbacks().onDelete(
-    [](SILInstruction *instToKill) {
-      // SimplifyInstruction is not in the business of removing
-      // copy_addr. If it were, then we would need to update deadCopies.
-      assert(!isa<CopyAddrInst>(instToKill));
-      instToKill->eraseFromParent();
-    }
-  );
-
-  DeadEndBlocks deBlocks(function);
-  for (auto *deadCopy : deadCopies) {
-    auto *srcInst = deadCopy->getSrc()->getDefiningInstruction();
-    deadCopy->eraseFromParent();
-    // Simplify any access scope markers that were only used by the dead
-    // copy_addr and other potentially unused addresses.
-    if (srcInst) {
-      simplifyAndReplaceAllSimplifiedUsesAndErase(srcInst, callbacks, &deBlocks);
-    }
-  }
-
-  // Call the utlity to complete ossa lifetime.
-  bool completedAny = false;
-  OSSALifetimeCompletion completion(function, da->get(function), deBlocks);
-  for (auto it : valuesToComplete) {
-    auto completed = completion.completeOSSALifetime(
-        it, OSSALifetimeCompletion::Boundary::Liveness);
-    completedAny = (completed == LifetimeCompletion::WasCompleted);
-  }
-
-  if (!deadCopies.empty() || completedAny) {
-    invalidateAnalysis(SILAnalysis::InvalidationKind::Instructions);
-  }
-}
-
-SILTransform *swift::createTempRValueOpt() { return new TempRValueOptPass(); }
diff --git a/lib/SILOptimizer/UtilityPasses/Link.cpp b/lib/SILOptimizer/UtilityPasses/Link.cpp
index ab761b8e1013e..2e60fa11780e6 100644
--- a/lib/SILOptimizer/UtilityPasses/Link.cpp
+++ b/lib/SILOptimizer/UtilityPasses/Link.cpp
@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "swift/AST/ProtocolConformance.h"
 #include "swift/SILOptimizer/PassManager/Passes.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SIL/SILModule.h"
@@ -48,6 +49,7 @@ class SILLinker : public SILModuleTransform {
     // (swift_retain, etc.). Link them in so they can be referenced in IRGen.
     if (M.getOptions().EmbeddedSwift && LinkEmbeddedRuntime) {
       linkEmbeddedRuntimeFromStdlib();
+      linkEmbeddedConcurrency();
     }
 
     // In embedded Swift, we need to explicitly link any @_used globals and
@@ -80,6 +82,36 @@ class SILLinker : public SILModuleTransform {
       linkEmbeddedRuntimeFunctionByName("swift_retainCount", { RefCounting });
   }
 
+  void linkEmbeddedConcurrency() {
+    using namespace RuntimeConstants;
+
+    // Note: we ignore errors here, because, depending on the exact situation
+    //
+    //    (a) We might not have Concurrency anyway, and
+    //
+    //    (b) The Impl function might be implemented in C++.
+    //
+    // Also, the hook Impl functions are marked as internal, unlike the
+    // runtime functions, which are public.
+
+#define SWIFT_CONCURRENCY_HOOK(RETURNS, NAME, ...)                  \
+  linkUsedFunctionByName(#NAME "Impl", SILLinkage::HiddenExternal)
+#define SWIFT_CONCURRENCY_HOOK0(RETURNS, NAME)                      \
+  linkUsedFunctionByName(#NAME "Impl", SILLinkage::HiddenExternal)
+
+    #include "swift/Runtime/ConcurrencyHooks.def"
+
+    linkUsedFunctionByName("swift_task_asyncMainDrainQueueImpl",
+                           SILLinkage::HiddenExternal);
+    linkUsedFunctionByName("_swift_task_enqueueOnExecutor",
+                           SILLinkage::HiddenExternal);
+    linkUsedFunctionByName("swift_createDefaultExecutors",
+                           SILLinkage::HiddenExternal);
+    linkUsedFunctionByName("swift_getDefaultExecutor",
+                           SILLinkage::HiddenExternal);
+    linkEmbeddedRuntimeWitnessTables();
+  }
+
   void linkEmbeddedRuntimeFunctionByName(StringRef name,
                                          ArrayRef<RuntimeEffect> effects) {
     SILModule &M = *getModule();
@@ -96,6 +128,23 @@ class SILLinker : public SILModuleTransform {
     linkUsedFunctionByName(name, SILLinkage::PublicExternal);
   }
 
+  void linkEmbeddedRuntimeWitnessTables() {
+    SILModule &M = *getModule();
+
+    auto *mainActor = M.getASTContext().getMainActorDecl();
+    if (mainActor) {
+      for (auto *PC : mainActor->getAllConformances()) {
+        auto *ProtoDecl = PC->getProtocol();
+        if (ProtoDecl->getName().str() == "Actor") {
+          M.linkWitnessTable(PC, SILModule::LinkingMode::LinkAll);
+          if (auto *WT = M.lookUpWitnessTable(PC)) {
+            WT->setLinkage(SILLinkage::Public);
+          }
+        }
+      }
+    }
+  }
+
   SILFunction *linkUsedFunctionByName(StringRef name,
                                       std::optional<SILLinkage> Linkage) {
     SILModule &M = *getModule();
@@ -134,7 +183,7 @@ class SILLinker : public SILModuleTransform {
     // linked global variable.
     if (GV->isDefinition())
       GV->setLinkage(SILLinkage::Public);
-    
+
     return GV;
   }
 
diff --git a/lib/SILOptimizer/UtilityPasses/SerializeSILPass.cpp b/lib/SILOptimizer/UtilityPasses/SerializeSILPass.cpp
index ffad29fb43799..db266c8085b23 100644
--- a/lib/SILOptimizer/UtilityPasses/SerializeSILPass.cpp
+++ b/lib/SILOptimizer/UtilityPasses/SerializeSILPass.cpp
@@ -209,6 +209,7 @@ static bool hasOpaqueArchetype(TypeExpansionContext context,
   case SILInstructionKind::ObjCProtocolInst:
   case SILInstructionKind::ObjectInst:
   case SILInstructionKind::VectorInst:
+  case SILInstructionKind::VectorBaseAddrInst:
   case SILInstructionKind::TupleInst:
   case SILInstructionKind::TupleAddrConstructorInst:
   case SILInstructionKind::TupleExtractInst:
@@ -288,7 +289,6 @@ static bool hasOpaqueArchetype(TypeExpansionContext context,
   case SILInstructionKind::EndUnpairedAccessInst:
   case SILInstructionKind::StoreInst:
   case SILInstructionKind::AssignInst:
-  case SILInstructionKind::AssignByWrapperInst:
   case SILInstructionKind::AssignOrInitInst:
   case SILInstructionKind::MarkFunctionEscapeInst:
   case SILInstructionKind::DebugValueInst:
@@ -321,6 +321,7 @@ static bool hasOpaqueArchetype(TypeExpansionContext context,
   case SILInstructionKind::DifferentiabilityWitnessFunctionInst:
   case SILInstructionKind::BeginCOWMutationInst:
   case SILInstructionKind::EndCOWMutationInst:
+  case SILInstructionKind::EndCOWMutationAddrInst:
   case SILInstructionKind::IncrementProfilerCounterInst:
   case SILInstructionKind::GetAsyncContinuationInst:
   case SILInstructionKind::GetAsyncContinuationAddrInst:
diff --git a/lib/SILOptimizer/UtilityPasses/TestRunner.cpp b/lib/SILOptimizer/UtilityPasses/TestRunner.cpp
index bab10aefe451f..f7e732d13a379 100644
--- a/lib/SILOptimizer/UtilityPasses/TestRunner.cpp
+++ b/lib/SILOptimizer/UtilityPasses/TestRunner.cpp
@@ -48,7 +48,8 @@ class TestRunner : public SILFunctionTransform {
       auto *deadEndBlocksAnalysis = pass->getAnalysis<DeadEndBlocksAnalysis>();
       return deadEndBlocksAnalysis->get(function);
     }
-    SwiftPassInvocation *getSwiftPassInvocation() override {
+
+    SILContext *getSILContext() override {
       return &swiftPassInvocation;
     }
     SILPassManager *getPassManager() override { return pass->getPassManager(); }
diff --git a/lib/SILOptimizer/Utils/BasicBlockOptUtils.cpp b/lib/SILOptimizer/Utils/BasicBlockOptUtils.cpp
index 32bf17da930df..757e2329f1e29 100644
--- a/lib/SILOptimizer/Utils/BasicBlockOptUtils.cpp
+++ b/lib/SILOptimizer/Utils/BasicBlockOptUtils.cpp
@@ -285,3 +285,16 @@ bool SinkAddressProjections::cloneProjections() {
   }
   return true;
 }
+
+void SinkAddressProjections::dump() const {
+  llvm::dbgs() << "Old projections: ";
+  for (auto *proj : oldProjections) {
+    proj->dump();
+  }
+  if (auto *np = newProjections) {
+    llvm::dbgs() << "New projections: ";
+    for (auto *proj : *np) {
+      proj->dump();
+    }
+  }
+}
diff --git a/lib/SILOptimizer/Utils/CMakeLists.txt b/lib/SILOptimizer/Utils/CMakeLists.txt
index 43187c612694b..125f37032ef88 100644
--- a/lib/SILOptimizer/Utils/CMakeLists.txt
+++ b/lib/SILOptimizer/Utils/CMakeLists.txt
@@ -2,8 +2,8 @@ target_sources(swiftSILOptimizer PRIVATE
   BasicBlockOptUtils.cpp
   CFGOptUtils.cpp
   CanonicalizeInstruction.cpp
-  CanonicalizeOSSALifetime.cpp
-  CanonicalizeBorrowScope.cpp
+  OSSACanonicalizeOwned.cpp
+  OSSACanonicalizeGuaranteed.cpp
   CastOptimizer.cpp
   CheckedCastBrJumpThreading.cpp
   CompileTimeInterpolationUtils.cpp
diff --git a/lib/SILOptimizer/Utils/CanonicalizeBorrowScope.cpp b/lib/SILOptimizer/Utils/CanonicalizeBorrowScope.cpp
deleted file mode 100644
index e068d4cd2f3f6..0000000000000
--- a/lib/SILOptimizer/Utils/CanonicalizeBorrowScope.cpp
+++ /dev/null
@@ -1,886 +0,0 @@
-//===--- CanonicalizeBorrowScope.cpp - Canonicalize OSSA borrow scopes ----===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// TODO: Enable -canonical-ossa-rewrite-borrows by default (see
-/// CopyPropagation).
-///
-/// TODO: Add support for load_borrows, and reborrows by using persistentCopies.
-///
-/// TODO: Hoist struct/tuple with multiple operands out of borrow scopes if that
-/// ever happens. Consider modeling them as reborrows instead.
-///
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "copy-propagation"
-
-#include "swift/Basic/Assertions.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h"
-#include "swift/Basic/Defer.h"
-#include "swift/SIL/InstructionUtils.h"
-#include "swift/SIL/OwnershipUtils.h"
-#include "swift/SIL/Test.h"
-#include "swift/SILOptimizer/Utils/CFGOptUtils.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
-#include "swift/SILOptimizer/Utils/DebugOptUtils.h"
-#include "swift/SILOptimizer/Utils/InstructionDeleter.h"
-#include "swift/SILOptimizer/Utils/ValueLifetime.h"
-#include "llvm/ADT/Statistic.h"
-
-using namespace swift;
-
-//===----------------------------------------------------------------------===//
-//                           MARK: Local utilities
-//===----------------------------------------------------------------------===//
-
-static bool hasValueOwnership(SILValue value) {
-  return value->getOwnershipKind() == OwnershipKind::Guaranteed ||
-         value->getOwnershipKind() == OwnershipKind::Owned;
-}
-
-static SingleValueInstruction *asCopyOrMove(SILValue v) {
-  if (auto *copy = dyn_cast<CopyValueInst>(v))
-    return copy;
-  if (auto *move = dyn_cast<MoveValueInst>(v))
-    return move;
-  return nullptr;
-}
-
-/// Delete a chain of unused copies and moves leading to \p v.
-static void deleteCopyAndMoveChain(SILValue v, InstructionDeleter &deleter) {
-  while (auto *inst = asCopyOrMove(v)) {
-    if (!onlyHaveDebugUses(inst))
-      break;
-
-    v = inst->getOperand(CopyLikeInstruction::Src);
-    LLVM_DEBUG(llvm::dbgs() << "  Deleting " << *inst);
-    ++NumCopiesAndMovesEliminated;
-    deleter.forceDelete(inst);
-  }
-}
-
-//===----------------------------------------------------------------------===//
-//                        MARK: Rewrite borrow scopes
-//===----------------------------------------------------------------------===//
-
-/// Does this instruction forward ownership, and can it be hoisted out of a
-/// borrow scope or sunk to its uses?
-///
-/// Currently requires the first operand to forward ownership.
-///
-/// Handles:
-///   OwnershipForwardingConversionInst (all kinds of ref casts)
-///   OwnershipForwardingMultipleValueInstruction
-///     (DestructureStruct, DestructureTuple)
-///   FirstArgOwnershipForwardingSingleValueInst
-///     (Object, Enum, UncheckedEnumData, Open/InitExistentialRef,
-///      MarkDependence)
-///
-/// TODO:
-///   Enum, InitExistential, MarkDependence
-///   Struct, Tuple
-///   SelectEnum, SwitchEnum, CheckCastBranch
-bool CanonicalizeBorrowScope::isRewritableOSSAForward(SILInstruction *inst) {
-  if (!inst->isTriviallyDuplicatable())
-    return false;
-
-  // TODO: check other operands for dominance and even attempt to hoist them.
-  if (inst->getNumOperands() != 1)
-    return false;
-
-  if (!isa<OwnershipForwardingSingleValueInstruction>(inst) &&
-      !isa<OwnershipForwardingMultipleValueInstruction>(inst))
-    return false;
-
-  Operand *forwardedOper = &inst->getOperandRef(0);
-  // Trivial conversions do not need to be hoisted out of a borrow scope.
-  auto operOwnership = forwardedOper->getOperandOwnership();
-  if (operOwnership == OperandOwnership::TrivialUse)
-    return false;
-  // Don't mess with unowned conversions. They need to be copied immediately.
-  if (operOwnership != OperandOwnership::GuaranteedForwarding &&
-      operOwnership != OperandOwnership::ForwardingConsume) {
-    return false;
-  }
-  assert(operOwnership == OperandOwnership::GuaranteedForwarding ||
-         operOwnership == OperandOwnership::ForwardingConsume);
-
-  // Filter instructions that belong to a Forwarding*ValueInst mixin but
-  // cannot be converted to forward owned value (struct_extract).
-  if (!canOpcodeForwardOwnedValues(forwardedOper))
-    return false;
-
-  return true;
-}
-
-/// Return the root of a borrowed extended lifetime for \p def or invalid.
-///
-/// \p def may be any guaranteed value.
-SILValue CanonicalizeBorrowScope::getCanonicalBorrowedDef(SILValue def) {
-  while (true) {
-    if (def->getOwnershipKind() != OwnershipKind::Guaranteed)
-      break;
-
-    if (auto borrowedVal = BorrowedValue(def)) {
-      // Any def's that aren't filtered out here must be handled by
-      // computeBorrowLiveness.
-      switch (borrowedVal.kind) {
-      case BorrowedValueKind::Invalid:
-        llvm_unreachable("Using invalid case?!");
-      case BorrowedValueKind::SILFunctionArgument:
-      case BorrowedValueKind::BeginBorrow:
-        return def;
-
-      case BorrowedValueKind::LoadBorrow:
-      case BorrowedValueKind::Phi:
-      case BorrowedValueKind::BeginApplyToken:
-        break;
-      }
-    }
-    // Look through hoistable guaranteed forwarding instructions on the
-    // use-def chain.
-    SILInstruction *defInst = def->getDefiningInstruction();
-    if (!defInst)
-      break;
-
-    if (!CanonicalizeBorrowScope::isRewritableOSSAForward(defInst))
-      break;
-
-    def = defInst->getOperand(0);
-  }
-  return SILValue();
-}
-
-bool CanonicalizeBorrowScope::computeBorrowLiveness() {
-  switch (borrowedValue.kind) {
-  case BorrowedValueKind::Invalid:
-    llvm_unreachable("Used invalid");
-  case BorrowedValueKind::SILFunctionArgument:
-    // For efficiency, function arguments skip liveness.
-    return true;
-  case BorrowedValueKind::LoadBorrow:
-  case BorrowedValueKind::Phi:
-    // TODO: Canonicalize load_borrow scope and phi once consolidateBorrowScope
-    // can handle persistentCopies.
-    return false;
-  case BorrowedValueKind::BeginBorrow:
-  case BorrowedValueKind::BeginApplyToken:
-    break;
-  }
-  // Note that there is no need to look through any reborrows. The reborrowed
-  // value is considered a separate lifetime for canonicalization. Any copies of
-  // the reborrowed value will not be rewritten when canonicalizing the current
-  // borrow scope because they are "hidden" behind the reborrow.
-  borrowedValue.visitLocalScopeEndingUses([this](Operand *use) {
-    liveness->updateForUse(use->getUser(), /*lifetimeEnding*/ true);
-    return true;
-  });
-  return true;
-}
-
-/// Return the source of a use within a borrow scope. This is the use-def
-/// equivalent to the logic in visitBorrowScopeUses that recurses through
-/// copies. The use-def and def-use logic must be consistent.
-SILValue CanonicalizeBorrowScope::findDefInBorrowScope(SILValue value) {
-  while (auto *inst = asCopyOrMove(value)) {
-    auto *copy = dyn_cast<CopyValueInst>(inst);
-    if (copy && isPersistentCopy(copy))
-      return copy;
-
-    value = inst->getOperand(0);
-  }
-  return value;
-}
-
-/// Visit all extended uses within the borrow scope, looking through copies and
-/// moves. Call visitUse for uses which could potentially be outside the borrow
-/// scope. Call visitForwardingUse for hoistable forwarding operations which
-/// could potentially be inside the borrow scope.
-///
-/// The visitor may or may not be able to determine which uses are outside the
-/// scope, but it can filter uses that are definitely within the scope. For
-/// example, guaranteed uses and uses in live-out blocks must both be within
-/// the scope.
-///
-/// This def-use traversal is similar to findExtendedTransitiveGuaranteedUses(),
-/// however, to cover the canonical lifetime, it looks through copies. It also
-/// considers uses within the introduced borrow scope itself (instead of simply
-/// visiting the scope-ending uses). It does not, however, look into nested
-/// borrow scopes uses, since nested scopes are canonicalized independently.
-///
-/// \p innerValue is either the initial begin_borrow, or a forwarding operation
-/// within the borrow scope.
-template <typename Visitor>
-bool CanonicalizeBorrowScope::visitBorrowScopeUses(SILValue innerValue,
-                                                   Visitor &visitor) {
-  // defUseWorklist is used recursively here.
-  // This avoids revisiting uses in case we ever recurse through
-  // both structs and destructures.
-  unsigned defUseStart = defUseWorklist.size();
-  defUseWorklist.insert(innerValue);
-  while (defUseStart < defUseWorklist.size()) {
-    SILValue value = defUseWorklist.pop();
-    // Gather the uses before updating any of them.
-    // 'value' may be deleted in this loop after rewriting its last use.
-    // 'use' may become invalid after processing its user.
-
-    SmallVector<Operand *, 4> uses(value->getUses());
-    for (auto *use : uses) {
-      auto *user = use->getUser();
-      // Incidental uses, such as debug_value may be deleted before they can be
-      // processed. Their user will now be nullptr. This means that value
-      // is dead, so just bail.
-      if (!user)
-        break;
-
-      // Recurse through copies and moves.
-      if (auto *copy = dyn_cast<CopyValueInst>(user)) {
-        if (!isPersistentCopy(copy)) {
-          defUseWorklist.insert(copy);
-          continue;
-        }
-      } else if (auto *move = dyn_cast<MoveValueInst>(user)) {
-        if (!move->isLexical() || innerValue->isLexical()) {
-          defUseWorklist.insert(move);
-          continue;
-        }
-      }
-      // Note: debug_value uses are handled like normal uses here. If they are
-      // inner uses, they remain. If they are outer uses, then they will be
-      // stripped if needed when the outer copy or persistent copy is
-      // canonicalized.
-      switch (use->getOperandOwnership()) {
-      case OperandOwnership::NonUse:
-        break;
-      case OperandOwnership::TrivialUse:
-        llvm_unreachable("this operand cannot handle ownership");
-
-      case OperandOwnership::InteriorPointer:
-      case OperandOwnership::AnyInteriorPointer:
-      case OperandOwnership::EndBorrow:
-      case OperandOwnership::Reborrow:
-        // Ignore uses that must be within the borrow scope.
-        // Rewriting does not look through reborrowed values--it considers them
-        // part of a separate lifetime.
-        break;
-
-      case OperandOwnership::ForwardingUnowned:
-      case OperandOwnership::PointerEscape:
-        // Pointer escapes are only allowed if they use the guaranteed value,
-        // which means that the escaped value must be confined to the current
-        // borrow scope.
-        if (use->get()->getOwnershipKind() != OwnershipKind::Guaranteed &&
-            !isa<SILFunctionArgument>(borrowedValue.value)) {
-          return false;
-        }
-        if (!visitor.visitUse(use)) {
-          return false;
-        }
-        break;
-
-      case OperandOwnership::GuaranteedForwarding:
-      case OperandOwnership::ForwardingConsume:
-        if (CanonicalizeBorrowScope::isRewritableOSSAForward(user)) {
-          if (!visitor.visitForwardingUse(use)) {
-            return false;
-          }
-          break;
-        }
-        LLVM_FALLTHROUGH;
-
-      case OperandOwnership::Borrow:
-      case OperandOwnership::InstantaneousUse:
-      case OperandOwnership::UnownedInstantaneousUse:
-      case OperandOwnership::BitwiseEscape:
-      case OperandOwnership::DestroyingConsume:
-        if (!visitor.visitUse(use)) {
-          return false;
-        }
-        break;
-      } // end switch OperandOwnership
-    }
-  } // end def-use traversal
-  return true;
-}
-
-namespace {
-
-using OuterUsers = CanonicalizeBorrowScope::OuterUsers;
-
-/// Find all potential outer uses within a borrow scope.
-///
-/// Implements visitBorrowScopeUses<Visitor>
-class FindBorrowScopeUses {
-  CanonicalizeBorrowScope &scope;
-
-  /// useInsts are the potentially outer use instructions. This set is built up
-  /// recursively. It is pared down to only the outer uses outside this class by
-  /// filterOuterBorrowUseInsts.
-  OuterUsers useInsts;
-
-public:
-  FindBorrowScopeUses(CanonicalizeBorrowScope &scope) : scope(scope) {}
-
-  std::optional<OuterUsers> findUses() && {
-    scope.beginVisitBorrowScopeUses();
-    if (!scope.visitBorrowScopeUses(scope.getBorrowedValue().value, *this))
-      return std::nullopt;
-
-    return std::move(useInsts);
-  }
-
-  bool visitUse(Operand *use) {
-    // A guaranteed use can never be outside this borrow scope
-    if (use->get()->getOwnershipKind() == OwnershipKind::Guaranteed)
-      return true;
-    
-    auto *user = use->getUser();
-    if (!isUserInLiveOutBlock(user)) {
-      useInsts.insert(user);
-    }
-    if (auto borrowingOper = BorrowingOperand(use)) {
-      // For borrows, record the scope-ending instructions to outer use
-      // points. Note: The logic in filterOuterBorrowUseInsts that checks
-      // whether a borrow scope is an outer use must visit the same set of uses.
-      if (!borrowingOper.visitExtendedScopeEndingUses([&](Operand *endBorrow) {
-        auto *endInst = endBorrow->getUser();
-        if (!isUserInLiveOutBlock(endInst)) {
-          useInsts.insert(endInst);
-        }
-        return true;
-      })) {
-        // Bail out on dead borrow scopes and scopes with unknown uses.
-        return false;
-      }
-    }
-    return true;
-  }
-
-  // Recurse through forwards.
-  bool visitForwardingUse(Operand *use) {
-    auto *user = use->getUser();
-    if (!isUserInLiveOutBlock(user)) {
-      useInsts.insert(user);
-    }
-    for (auto result : user->getResults()) {
-      if (hasValueOwnership(result)) {
-        if (!scope.visitBorrowScopeUses(result, *this))
-          return false;
-      }
-    }
-    return true;
-  }
-
-protected:
-  bool isUserInLiveOutBlock(SILInstruction *user) {
-    return (scope.getLiveness().getBlockLiveness(user->getParent())
-            == PrunedLiveBlocks::LiveOut);
-    return false;
-  };
-};
-
-} // namespace
-
-/// Erase users from \p outerUseInsts that are actually within the borrow scope.
-void CanonicalizeBorrowScope::filterOuterBorrowUseInsts(
-    OuterUsers &outerUseInsts) {
-  auto *beginBorrow = cast<BeginBorrowInst>(borrowedValue.value);
-  SmallVector<SILInstruction *, 4> scopeEndingInsts;
-  BorrowedValue(beginBorrow).getLocalScopeEndingInstructions(scopeEndingInsts);
-  blockWorklist.clear();
-  // Remove outer uses that occur before the end of the borrow scope by
-  // reverse iterating from the end_borrow.
-  auto scanBlock = [&](SILBasicBlock *bb, SILBasicBlock::iterator endIter) {
-    auto beginIter = bb->begin();
-    if (bb == beginBorrow->getParent()) {
-      beginIter = std::next(beginBorrow->getIterator());
-    } else {
-      blockWorklist.insert(bb);
-    }
-    for (auto instIter = endIter; instIter != beginIter;) {
-      --instIter;
-      outerUseInsts.erase(&*instIter);
-    }
-  };
-  for (auto *scopeEnd : scopeEndingInsts) {
-    scanBlock(scopeEnd->getParent(), std::next(scopeEnd->getIterator()));
-  }
-  // This worklist is also a visited set, so we never pop the entries.
-  while (auto *bb = blockWorklist.pop()) {
-    for (auto *predBB : bb->getPredecessorBlocks()) {
-      scanBlock(predBB, predBB->end());
-    }
-  }
-}
-
-namespace {
-
-/// Remove redundant copies/destroys within a borrow scope.
-///
-/// The visitor callbacks must always return true since this rewrites in-place.
-class RewriteInnerBorrowUses {
-  CanonicalizeBorrowScope &scope;
-
-public:
-  RewriteInnerBorrowUses(CanonicalizeBorrowScope &scope): scope(scope) {}
-
-  CanonicalizeBorrowScope &getScope() const { return scope; }
-
-  // Implements visitBorrowScopeUses<Visitor>
-  bool visitUse(Operand *use) {
-    auto *user = use->getUser();
-    SILValue value = use->get();
-    // destroys are never needed within a borrow scope.
-    if (isa<DestroyValueInst>(user)) {
-      scope.getDeleter().forceDelete(user);
-      deleteCopyAndMoveChain(value, scope.getDeleter());
-      return true;
-    }
-    SILValue def = scope.findDefInBorrowScope(value);
-    if (use->isConsuming()) {
-      if (use->get()->getType().isMoveOnly()) {
-        // Can't produce a copy of a non-copyable value on demand.  Bail out.
-        return false;
-      }
-      // All in-scope consuming uses need a unique copy in the same block.
-      auto *copy = dyn_cast<CopyValueInst>(use->get());
-      if (copy && copy->hasOneUse() && copy->getParent() == user->getParent()) {
-        value = copy->getOperand();
-        copy->setOperand(def);
-      } else {
-        use->set(def);
-        copyLiveUse(use, scope.getCallbacks());
-      }
-      deleteCopyAndMoveChain(value, scope.getDeleter());
-      return true;
-    }
-    // Non-consuming use.
-    use->set(def);
-    deleteCopyAndMoveChain(value, scope.getDeleter());
-    return true;
-  }
-
-  // Recurse through forwards.
-  //
-  // Implements visitBorrowScopeUses<Visitor>
-  bool visitForwardingUse(Operand *use) {
-    auto *user = use->getUser();
-    assert(CanonicalizeBorrowScope::isRewritableOSSAForward(user));
-
-    for (auto result : user->getResults()) {
-      if (!hasValueOwnership(result)) {
-        continue;
-      }
-      if (!scope.visitBorrowScopeUses(result, *this)) {
-        return false;
-      }
-    }
-    // Update this operand bypassing any copies.
-    SILValue value = use->get();
-    use->set(scope.findDefInBorrowScope(value));
-    ForwardingOperand(use).setForwardingOwnershipKind(
-        OwnershipKind::Guaranteed);
-    deleteCopyAndMoveChain(value, scope.getDeleter());
-    return true;
-  }
-};
-
-/// Generate copies outside this borrow scope, hoist forwarding operations,
-/// rewrite the operands of uses outside the scope, and record the outer uses
-/// that are consumes.
-///
-/// Each hoisted forwarding operation instantiates a new instance of this
-/// visitor. They are rewritten separately.
-///
-/// Implements visitBorrowScopeUses<Visitor>
-///
-/// The visitor callbacks must always return true since this rewrites in-place.
-class RewriteOuterBorrowUses {
-  CanonicalizeBorrowScope &scope;
-
-  RewriteInnerBorrowUses &innerRewriter;
-
-  const OuterUsers &outerUseInsts;
-
-  /// Map values inside the borrow scope to cloned-and-copied values outside the
-  /// borrow scope.
-  using InnerToOuterMap = llvm::SmallDenseMap<SILValue, SILValue, 8>;
-  InnerToOuterMap &innerToOuterMap;
-
-  // Outer uses specific to the current incomingValue, including hoisted
-  // forwarding instructions, which are not part of outerUseInsts.
-  SmallVector<Operand *, 4> consumingUses;
-  SmallPtrSet<SILInstruction *, 4> unclaimedConsumingUsers;
-
-  RewriteOuterBorrowUses(RewriteInnerBorrowUses &innerRewriter,
-                         const OuterUsers &outerUseInsts,
-                         InnerToOuterMap &innerToOuterMap)
-    : scope(innerRewriter.getScope()), innerRewriter(innerRewriter),
-      outerUseInsts(outerUseInsts), innerToOuterMap(innerToOuterMap) {}
-
-public:
-  static void rewrite(BeginBorrowInst *beginBorrow,
-                      CanonicalizeBorrowScope &scope,
-                      const OuterUsers &outerUseInsts) {
-
-    SILBuilderWithScope builder(beginBorrow);
-    auto loc = RegularLocation::getAutoGeneratedLocation(beginBorrow->getLoc());
-    auto *outerCopy =
-        createOuterCopy(beginBorrow->getOperand(), builder, loc, scope);
-
-    llvm::SmallDenseMap<SILValue, SILValue, 8> innerToOuterMap;
-    innerToOuterMap[beginBorrow] = outerCopy;
-
-    RewriteInnerBorrowUses innerRewriter(scope);
-    RewriteOuterBorrowUses rewriter(innerRewriter, outerUseInsts,
-                                    innerToOuterMap);
-    scope.beginVisitBorrowScopeUses();
-    auto outerVal = rewriter.recursivelyRewriteOuterUses(beginBorrow);
-    assert(outerVal == outerCopy);
-  }
-
-  // Implements visitBorrowScopeUses<Visitor>
-  bool visitUse(Operand *use) {
-    auto *user = use->getUser();
-    if (outerUseInsts.count(user)) {
-      rewriteOuterUse(use);
-      return true;
-    }
-    // If this use begins a borrow scope, check if any of the scope ending
-    // instructions are outside the current scope (this can happen if any copy
-    // has occurred on the def-use chain within the current scope).
-    if (auto borrowingOper = BorrowingOperand(use)) {
-      if (!borrowingOper.visitExtendedScopeEndingUses(
-            [&](Operand *endBorrow) {
-              return !outerUseInsts.count(endBorrow->getUser());
-            })) {
-        rewriteOuterUse(use);
-        return true;
-      }
-    }
-    innerRewriter.visitUse(use);
-    return true;
-  }
-
-  // Recurse through forwards.
-  //
-  // Implements visitBorrowScopeUses<Visitor>
-  bool visitForwardingUse(Operand *use) {
-    auto *user = use->getUser();
-    assert(CanonicalizeBorrowScope::isRewritableOSSAForward(user));
-    if (outerUseInsts.count(user)) {
-      rewriteOuterUse(use);
-      return true;
-    }
-
-    // Process transitive users and add this forwarding operation to
-    // outerUseInsts if any outer uses were found.
-    SILInstruction *outerClone = nullptr;
-    for (auto result : user->getResults()) {
-      if (!hasValueOwnership(result)) {
-        continue;
-      }
-      RewriteOuterBorrowUses rewriter(innerRewriter, outerUseInsts,
-                                      innerToOuterMap);
-      auto outerVal = rewriter.recursivelyRewriteOuterUses(result);
-      if (outerVal)
-        outerClone = outerVal->getDefiningInstruction();
-    }
-    // Record the forwarded operand of this hoisted instruction as an outer use.
-    if (outerClone) {
-      recordOuterUse(&outerClone->getOperandRef(0));
-    }
-    // If it's not already dead, update this operand bypassing any copies.
-    SILValue innerValue = use->get();
-    if (scope.getDeleter().deleteIfDead(user, /*fixLifetime=*/false)) {
-      LLVM_DEBUG(llvm::dbgs() << "  Deleted " << *user);
-    } else {
-      use->set(scope.findDefInBorrowScope(use->get()));
-      ForwardingOperand(use).setForwardingOwnershipKind(
-          OwnershipKind::Guaranteed);
-    }
-    deleteCopyAndMoveChain(innerValue, scope.getDeleter());
-    return true;
-  }
-
-protected:
-  // Create a copy for outer uses of the borrow scope introduced by
-  // currentDef. This copy should only be used by outer uses in the same block
-  // as the borrow scope.
-  //
-  // To use an existing outer copy, we could find its earliest consume. But the
-  // new copy will immediately canonicalized and a canonical begin_borrow scope
-  // have no outer uses of its first block.
-  static CopyValueInst *createOuterCopy(SILValue incomingValue,
-                                        SILBuilder &builder, SILLocation loc,
-                                        CanonicalizeBorrowScope &scope) {
-    auto *copy = builder.createCopyValue(loc, incomingValue);
-    scope.getCallbacks().createdNewInst(copy);
-    scope.recordOuterCopy(copy);
-
-    ++NumCopiesGenerated;
-    LLVM_DEBUG(llvm::dbgs() << "  Outer copy " << *copy);
-
-    return copy;
-  }
-
-  SILValue recursivelyRewriteOuterUses(SILValue innerValue) {
-    bool succeed = scope.visitBorrowScopeUses(innerValue, *this);
-    assert(succeed && "should be filtered by FindBorrowScopeUses");
-
-    auto iter = innerToOuterMap.find(innerValue);
-    if (iter == innerToOuterMap.end()) {
-      return SILValue();
-    }
-    SILValue outerValue = iter->second;
-    cleanupOuterValue(outerValue);
-    return outerValue;
-  }
-
-  void recordOuterUse(Operand *use) {
-    if (use->isLifetimeEnding()) {
-      consumingUses.push_back(use);
-      unclaimedConsumingUsers.insert(use->getUser());
-    }
-  };
-
-  void rewriteOuterUse(Operand *use) {
-    LLVM_DEBUG(llvm::dbgs() << "  Use of outer copy " << *use->getUser());
-
-    SILValue innerValue = use->get();
-    SILValue outerValue = createOuterValues(innerValue);
-
-    use->set(outerValue);
-
-    deleteCopyAndMoveChain(innerValue, scope.getDeleter());
-
-    recordOuterUse(use);
-  };
-
-  SILValue createOuterValues(SILValue innerValue);
-
-  void cleanupOuterValue(SILValue outerValue);
-};
-
-} // namespace
-
-// Incrementally create a def-use chain outside the current borrow scope for
-// all instructions between currentDef and \p innerValue, where \p innerValue
-// has at least one use outside the borrow scope.
-SILValue RewriteOuterBorrowUses::createOuterValues(SILValue innerValue) {
-  // Poke through the copies just like rewriteOuterBorrowUsesAndFindConsumes
-  // does on the def-use side.
-  while (auto *copy = dyn_cast<CopyValueInst>(innerValue)) {
-    innerValue = copy->getOperand();
-  }
-  auto iter = innerToOuterMap.find(innerValue);
-  if (iter != innerToOuterMap.end()) {
-    return iter->second;
-  }
-  auto *innerInst = innerValue->getDefiningInstruction();
-  assert(CanonicalizeBorrowScope::isRewritableOSSAForward(innerInst));
-  SILValue incomingInnerVal = innerInst->getOperand(0);
-
-  auto incomingOuterVal = createOuterValues(incomingInnerVal);
-
-  auto *insertPt = innerValue->getDefiningInsertionPoint();
-  auto *clone = innerInst->clone(insertPt);
-  scope.getCallbacks().createdNewInst(clone);
-  Operand *use = &clone->getOperandRef(0);
-  use->set(incomingOuterVal);
-  ForwardingOperand(use).setForwardingOwnershipKind(OwnershipKind::Owned);
-
-  LLVM_DEBUG(llvm::dbgs() << "  Hoisted forward " << *clone);
-
-  for (unsigned idx = 0, endIdx = clone->getNumResults(); idx < endIdx; ++idx) {
-    innerToOuterMap[innerInst->getResult(idx)] = clone->getResult(idx);
-  }
-  return innerToOuterMap[innerValue];
-}
-
-// Insert destroys on the outer copy's or forwarding consume's lifetime
-// frontier, or claim a existing consumes. Insert copies for unclaimed consumes.
-void RewriteOuterBorrowUses::cleanupOuterValue(SILValue outerValue) {
-  // Gather outerValue's transitive ownership uses for ValueLifetimeAnalysis.
-  SmallVector<SILInstruction *, 4> outerUses;
-  for (Operand *use : outerValue->getUses()) {
-    outerUses.push_back(use->getUser());
-    if (auto borrowingOper = BorrowingOperand(use)) {
-      borrowingOper.visitExtendedScopeEndingUses([&](Operand *endBorrow) {
-        outerUses.push_back(endBorrow->getUser());
-        return true;
-      });
-    }
-  }
-  ValueLifetimeAnalysis lifetimeAnalysis(outerValue.getDefiningInstruction(),
-                                         outerUses);
-
-  auto createDestroy = [&](SILBuilder &b, SILLocation loc) {
-      auto *dvi = b.createDestroyValue(loc, outerValue);
-      scope.getCallbacks().createdNewInst(dvi);
-  };
-  if (outerUses.empty()) {
-    SILBuilder b(outerValue->getNextInstruction());
-    createDestroy(b, outerValue.getLoc());
-    return;
-  }
-
-  ValueLifetimeBoundary boundary;
-  lifetimeAnalysis.computeLifetimeBoundary(boundary);
-
-  for (auto *boundaryEdge : boundary.boundaryEdges) {
-    if (DeadEndBlocks::triviallyEndsInUnreachable(boundaryEdge))
-      continue;
-    auto insertPt = boundaryEdge->begin();
-    auto *dvi = SILBuilderWithScope(insertPt).createDestroyValue(
-        insertPt->getLoc(), outerValue);
-    scope.getCallbacks().createdNewInst(dvi);
-  }
-
-  for (SILInstruction *lastUser : boundary.lastUsers) {
-    if (unclaimedConsumingUsers.erase(lastUser))
-      continue;
-
-    SILBuilderWithScope::insertAfter(lastUser, [&](SILBuilder &b) {
-      createDestroy(b, lastUser->getLoc());
-    });
-  }
-  // Add copies for consuming users of outerValue.
-  for (auto *use : consumingUses) {
-    // If the user is still in the unclaimedConsumingUsers set, then it does not
-    // end the outer copy's lifetime and therefore requires a copy. Only one
-    // operand can be claimed as ending the lifetime, so return its user to the
-    // unclaimedConsumingUsers set after skipping the first copy.
-    auto iterAndInserted = unclaimedConsumingUsers.insert(use->getUser());
-    if (!iterAndInserted.second) {
-      copyLiveUse(use, scope.getCallbacks());
-      scope.recordOuterCopy(cast<CopyValueInst>(use->get()));
-    }
-  }
-}
-
-// If this succeeds, then all uses of the borrowed value outside the borrow
-// scope will be rewritten to use an outer copy, and all remaining uses of the
-// borrowed value will be confined to the borrow scope.
-//
-// TODO: Canonicalize multi-block borrow scopes, load_borrow scope, and phi
-// borrow scopes by adding one copy per block to persistentCopies for
-// each block that dominates an outer use.
-bool CanonicalizeBorrowScope::consolidateBorrowScope() {
-  OuterUsers outerUseInsts;
-  if (!isa<SILFunctionArgument>(borrowedValue.value)) {
-    // getCanonicalCopiedDef ensures that if currentDef is a guaranteed value,
-    // then it is a borrow scope introducer.
-    assert(borrowedValue.isLocalScope());
-
-    // Gather all potential outer uses before rewriting any to avoid scanning
-    // any basic block more than once.
-    std::optional<OuterUsers> outerUsers =
-        FindBorrowScopeUses(*this).findUses();
-    if (!outerUsers)
-      return false;
-
-    outerUseInsts = std::move(outerUsers).value();
-
-    filterOuterBorrowUseInsts(outerUseInsts);
-  }
-  // If there are no outer uses, then canonicalization is a simple matter of
-  // removing all the destroys and rewriting the copies.
-  if (outerUseInsts.empty()) {
-    RewriteInnerBorrowUses innerRewriter(*this);
-    beginVisitBorrowScopeUses(); // reset the def/use worklist
-    return visitBorrowScopeUses(borrowedValue.value, innerRewriter);
-  }
-  LLVM_DEBUG(llvm::dbgs() << "  Outer uses:\n";
-             for (SILInstruction *inst
-                  : outerUseInsts) { llvm::dbgs() << "    " << *inst; });
-
-  RewriteOuterBorrowUses::rewrite(cast<BeginBorrowInst>(borrowedValue.value),
-                                  *this, outerUseInsts);
-  return true;
-}
-
-//===----------------------------------------------------------------------===//
-//                  MARK: Top-Level CanonicalizeBorrowScope
-//===----------------------------------------------------------------------===//
-
-bool CanonicalizeBorrowScope::canonicalizeFunctionArgument(
-    SILFunctionArgument *arg) {
-  BorrowedValue borrow(arg);
-  if (!borrow)
-    return false;
-
-  initBorrow(borrow);
-
-  LLVM_DEBUG(llvm::dbgs() << "*** Canonicalize Borrow: " << borrowedValue);
-
-  RewriteInnerBorrowUses innerRewriter(*this);
-  beginVisitBorrowScopeUses(); // reset the def/use worklist
-
-  return visitBorrowScopeUses(borrowedValue.value, innerRewriter);
-}
-
-namespace swift::test {
-// Arguments:
-// - SILFunctionArgument: function argument to canonicalize
-// Dumps:
-// - function after argument canonicalization
-static FunctionTest CanonicalizeFunctionArgumentTest(
-    "canonicalize_function_argument",
-    [](auto &function, auto &arguments, auto &test) {
-      auto *argument = cast<SILFunctionArgument>(arguments.takeBlockArgument());
-      InstructionDeleter deleter;
-      CanonicalizeBorrowScope canonicalizer(&function, deleter);
-      canonicalizer.canonicalizeFunctionArgument(argument);
-      function.print(llvm::outs());
-    });
-} // end namespace swift::test
-
-/// Canonicalize a worklist of extended lifetimes. This iterates after rewriting
-/// borrow scopes to handle new outer copies and new owned lifetimes from
-/// forwarding operations.
-bool CanonicalizeBorrowScope::
-canonicalizeBorrowScope(BorrowedValue borrowedValue) {
-  BitfieldRef<SSAPrunedLiveness>::StackState livenessBitfieldContainer(
-      liveness, function);
-
-  LLVM_DEBUG(llvm::dbgs() << "*** Canonicalize Borrow: " << borrowedValue);
-
-  initBorrow(borrowedValue);
-
-  if (!computeBorrowLiveness())
-    return false;
-
-  // Set outerCopy and persistentCopies and rewrite uses
-  // outside the scope.
-  if (!consolidateBorrowScope())
-    return false;
-
-  return true;
-}
-
-namespace swift::test {
-// Arguments:
-// - SILValue: value to canonicalize
-// Dumps:
-// - function after value canonicalization
-static FunctionTest CanonicalizeBorrowScopeTest(
-    "canonicalize_borrow_scope",
-    [](auto &function, auto &arguments, auto &test) {
-      auto value = arguments.takeValue();
-      auto borrowedValue = BorrowedValue(value);
-      assert(borrowedValue && "specified value isn't a BorrowedValue!?");
-      InstructionDeleter deleter;
-      CanonicalizeBorrowScope canonicalizer(value->getFunction(), deleter);
-      canonicalizer.canonicalizeBorrowScope(borrowedValue);
-      function.print(llvm::outs());
-    });
-} // end namespace swift::test
diff --git a/lib/SILOptimizer/Utils/CanonicalizeInstruction.cpp b/lib/SILOptimizer/Utils/CanonicalizeInstruction.cpp
index 42e9c1c220b94..e4165502ba9d1 100644
--- a/lib/SILOptimizer/Utils/CanonicalizeInstruction.cpp
+++ b/lib/SILOptimizer/Utils/CanonicalizeInstruction.cpp
@@ -548,6 +548,10 @@ static SILBasicBlock::iterator
 eliminateUnneededForwardingUnarySingleValueInst(SingleValueInstruction *inst,
                                                 CanonicalizeInstruction &pass) {
   auto next = std::next(inst->getIterator());
+  if (inst->getType().isValueTypeWithDeinit()) {
+    // Avoid bypassing non-Copyable struct/enum deinitializers.
+    return next;
+  }
   if (isa<DropDeinitInst>(inst))
     return next;
   if (auto *uedi = dyn_cast<UncheckedEnumDataInst>(inst)) {
diff --git a/lib/SILOptimizer/Utils/CanonicalizeOSSALifetime.cpp b/lib/SILOptimizer/Utils/CanonicalizeOSSALifetime.cpp
deleted file mode 100644
index 813d58d326fe1..0000000000000
--- a/lib/SILOptimizer/Utils/CanonicalizeOSSALifetime.cpp
+++ /dev/null
@@ -1,1523 +0,0 @@
-//===-- CanonicalizeOSSALifetime.cpp - Canonicalize OSSA value lifetimes --===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// This top-level API rewrites the extended lifetime of a SILValue:
-///
-///     bool CanonicalizeOSSALifetime::canonicalizeValueLifetime(SILValue def)
-///
-/// Each time it's called on a single OSSA value, `def`, it performs four
-/// steps:
-///
-/// 1. Compute "pruned" liveness of def and its copies, ignoring original
-///    destroys. Initializes `liveness`.
-///
-/// 2. Find the "original" boundary of liveness using
-///    PrunedLiveness::computeBoundary.
-///
-/// 3. (Optional) At Onone, extend liveness up to original extent when possible
-///    without incurring extra copies.
-///
-/// 4. Find the "extended" boundary of liveness by walking out from the boundary
-///    computed by PrunedLiveness out to destroys which aren't separated from
-///    the original destory by "interesting" instructions.
-///
-/// 5. Initializes `consumes` and inserts new destroy_value instructions.
-///
-/// 6. Rewrite `def`s original copies and destroys, inserting new copies where
-///    needed. Deletes original copies and destroys and inserts new copies.
-///
-/// See CanonicalizeOSSALifetime.h for examples.
-///
-/// TODO: Canonicalization currently bails out if any uses of the def has
-/// OperandOwnership::PointerEscape. Once project_box is protected by a borrow
-/// scope and mark_dependence is associated with an end_dependence, those will
-/// no longer be represented as PointerEscapes, and canonicalization will
-/// naturally work everywhere as intended. The intention is to keep the
-/// canonicalization algorithm as simple and robust, leaving the remaining
-/// performance opportunities contingent on fixing the SIL representation.
-///
-/// TODO: Replace BasicBlock SmallDenseMaps with inlined bits;
-/// see BasicBlockDataStructures.h.
-///
-/// TODO: This algorithm would be extraordinarily simple and cheap except for
-/// the following issues:
-///
-/// 1. Liveness is extended by any overlapping begin/end_access scopes. This
-/// avoids calling a destructor within an exclusive access. A simpler
-/// alternative would be to model all end_access instructions as deinit
-/// barriers, but that may significantly limit optimization.
-///
-/// 2. Liveness is extended out to original destroys to avoid spurious changes.
-///
-/// 3. In the Onone mode, liveness is preserved to its previous extent whenever
-/// doing so doesn't incur extra copies compared to what is done in the O mode.
-///
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "copy-propagation"
-
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
-#include "swift/Basic/Assertions.h"
-#include "swift/SIL/InstructionUtils.h"
-#include "swift/SIL/NodeDatastructures.h"
-#include "swift/SIL/OSSALifetimeCompletion.h"
-#include "swift/SIL/OwnershipUtils.h"
-#include "swift/SIL/PrunedLiveness.h"
-#include "swift/SIL/Test.h"
-#include "swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h"
-#include "swift/SILOptimizer/Analysis/Reachability.h"
-#include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CFGOptUtils.h"
-#include "swift/SILOptimizer/Utils/DebugOptUtils.h"
-#include "swift/SILOptimizer/Utils/InstructionDeleter.h"
-#include "swift/SILOptimizer/Utils/ValueLifetime.h"
-#include "llvm/ADT/Statistic.h"
-
-using namespace swift;
-using llvm::SmallSetVector;
-
-llvm::Statistic swift::NumCopiesAndMovesEliminated = {
-    DEBUG_TYPE, "NumCopiesAndMovesEliminated",
-    "number of copy_value and move_value instructions removed"};
-
-llvm::Statistic swift::NumCopiesGenerated = {
-    DEBUG_TYPE, "NumCopiesGenerated",
-    "number of copy_value instructions created"};
-
-STATISTIC(NumDestroysEliminated,
-          "number of destroy_value instructions removed");
-STATISTIC(NumDestroysGenerated, "number of destroy_value instructions created");
-
-//===----------------------------------------------------------------------===//
-//                           MARK: General utilities
-//===----------------------------------------------------------------------===//
-
-template <typename... T, typename... U>
-static void diagnose(ASTContext &Context, SourceLoc loc, Diag<T...> diag,
-                     U &&...args) {
-  Context.Diags.diagnose(loc, diag, std::forward<U>(args)...);
-}
-
-/// Is \p instruction a destroy_value whose operand is \p def, or its
-/// transitive copy.
-static bool isDestroyOfCopyOf(SILInstruction *instruction, SILValue def) {
-  auto *destroy = dyn_cast<DestroyValueInst>(instruction);
-  if (!destroy)
-    return false;
-  auto destroyed = destroy->getOperand();
-  while (true) {
-    if (destroyed == def)
-      return true;
-    auto *copy = dyn_cast<CopyValueInst>(destroyed);
-    if (!copy)
-      break;
-    destroyed = copy->getOperand();
-  }
-  return false;
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: Step 1. Compute pruned liveness
-//===----------------------------------------------------------------------===//
-
-bool CanonicalizeOSSALifetime::computeCanonicalLiveness() {
-  LLVM_DEBUG(llvm::dbgs() << "Computing canonical liveness from:\n";
-             getCurrentDef()->print(llvm::dbgs()));
-  SmallVector<unsigned, 8> indexWorklist;
-  ValueSet visitedDefs(getCurrentDef()->getFunction());
-  auto addDefToWorklist = [&](Def def) {
-    if (!visitedDefs.insert(def.value))
-      return;
-    discoveredDefs.push_back(def);
-    indexWorklist.push_back(discoveredDefs.size() - 1);
-  };
-  discoveredDefs.clear();
-  addDefToWorklist(Def::root(getCurrentDef()));
-  // Only the first level of reborrows need to be consider. All nested inner
-  // adjacent reborrows and phis are encapsulated within their lifetimes.
-  SILPhiArgument *arg;
-  if ((arg = dyn_cast<SILPhiArgument>(getCurrentDef())) && arg->isPhi()) {
-    visitInnerAdjacentPhis(arg, [&](SILArgument *reborrow) {
-      addDefToWorklist(Def::reborrow(reborrow));
-      return true;
-    });
-  }
-  while (!indexWorklist.empty()) {
-    auto index = indexWorklist.pop_back_val();
-    auto def = discoveredDefs[index];
-    auto value = def.value;
-    LLVM_DEBUG(llvm::dbgs() << "  Uses of value:\n";
-               value->print(llvm::dbgs()));
-
-    for (Operand *use : value->getUses()) {
-      LLVM_DEBUG(llvm::dbgs() << "    Use:\n";
-                 use->getUser()->print(llvm::dbgs()));
-
-      auto *user = use->getUser();
-      // Recurse through copies.
-      if (auto *copy = dyn_cast<CopyValueInst>(user)) {
-        // Don't recurse through copies of borrowed-froms or reborrows.
-        switch (def.kind) {
-        case Def::Root:
-        case Def::Copy:
-          addDefToWorklist(Def::copy(copy));
-          break;
-        case Def::Reborrow:
-        case Def::BorrowedFrom:
-          break;
-        }
-        continue;
-      }
-      if (auto *bfi = dyn_cast<BorrowedFromInst>(user)) {
-        addDefToWorklist(Def::borrowedFrom(bfi));
-        continue;
-      }
-      // Handle debug_value instructions separately.
-      if (pruneDebugMode) {
-        if (auto *dvi = dyn_cast<DebugValueInst>(user)) {
-          // Only instructions potentially outside current pruned liveness are
-          // interesting.
-          if (liveness->getBlockLiveness(dvi->getParent())
-              != PrunedLiveBlocks::LiveOut) {
-            recordDebugValue(dvi);
-          }
-          continue;
-        }
-      }
-      switch (use->getOperandOwnership()) {
-      case OperandOwnership::NonUse:
-        break;
-      case OperandOwnership::TrivialUse:
-        llvm_unreachable("this operand cannot handle ownership");
-
-      // Conservatively treat a conversion to an unowned value as a pointer
-      // escape. Is it legal to canonicalize ForwardingUnowned?
-      case OperandOwnership::ForwardingUnowned:
-      case OperandOwnership::PointerEscape:
-        LLVM_DEBUG(llvm::dbgs() << "      Value escaped! Giving up\n");
-        return false;
-      case OperandOwnership::InstantaneousUse:
-      case OperandOwnership::UnownedInstantaneousUse:
-      case OperandOwnership::BitwiseEscape:
-        liveness->updateForUse(user, /*lifetimeEnding*/ false);
-        break;
-      case OperandOwnership::ForwardingConsume:
-        recordConsumingUse(use);
-        liveness->updateForUse(user, /*lifetimeEnding*/ true);
-        break;
-      case OperandOwnership::DestroyingConsume:
-        if (isDestroyOfCopyOf(user, getCurrentDef())) {
-          destroys.insert(user);
-        } else {
-          // destroy_value of a transitive copy of the currentDef does not
-          // force pruned liveness (but store etc. does).
-
-          // Even though this instruction is a DestroyingConsume of its operand,
-          // if it's a destroy_value whose operand is not a transitive copy of
-          // currentDef, then it's just ending an implicit borrow of currentDef,
-          // not consuming it.
-          auto lifetimeEnding = !isa<DestroyValueInst>(user);
-          liveness->updateForUse(user, lifetimeEnding);
-        }
-        recordConsumingUse(use);
-        break;
-      case OperandOwnership::Borrow:
-        if (liveness->updateForBorrowingOperand(use)
-              != InnerBorrowKind::Contained) {
-          LLVM_DEBUG(llvm::dbgs() << "      Inner borrow can't be contained! Giving up\n");
-          return false;
-        }
-        break;
-      case OperandOwnership::InteriorPointer:
-      case OperandOwnership::AnyInteriorPointer:
-        if (liveness->checkAndUpdateInteriorPointer(use) !=
-            AddressUseKind::NonEscaping) {
-          LLVM_DEBUG(llvm::dbgs()
-                     << "      Inner address use is escaping! Giving up\n");
-          return false;
-        }
-        break;
-      case OperandOwnership::GuaranteedForwarding:
-      case OperandOwnership::EndBorrow:
-        // Guaranteed values are exposed by inner adjacent reborrows. If user is
-        // a guaranteed phi (GuaranteedForwarding), then the owned lifetime
-        // either dominates it or its lifetime ends at an outer adjacent
-        // reborrow. Only instructions that end the reborrow lifetime should
-        // actually affect liveness of the outer owned value.
-        liveness->updateForUse(user, /*lifetimeEnding*/ false);
-        break;
-      case OperandOwnership::Reborrow:
-        BranchInst *branch = cast<BranchInst>(user);
-        // This is a cheap variation on visitEnclosingDef. We already know that
-        // getCurrentDef() is the enclosing def for this use. If the reborrow's
-        // has a enclosing def is an outer adjacent phi then this branch must
-        // consume getCurrentDef() as the outer phi operand.
-        if (is_contained(branch->getOperandValues(), getCurrentDef())) {
-          // An adjacent phi consumes the value being reborrowed. Although this
-          // use doesn't end the lifetime, this branch does end the lifetime by
-          // consuming the owned value.
-          liveness->updateForUse(branch, /*lifetimeEnding*/ true);
-          break;
-        }
-        // No adjacent phi consumes the value.  This use is not lifetime ending.
-        liveness->updateForUse(branch, /*lifetimeEnding*/ false);
-        // This branch reborrows a guaranteed phi whose lifetime is dependent on
-        // currentDef.  Uses of the reborrowing phi extend liveness.
-        auto *reborrow = PhiOperand(use).getValue();
-        addDefToWorklist(Def::reborrow(reborrow));
-        break;
-      }
-    }
-  }
-  return true;
-}
-
-/// Extend liveness to the availability boundary of currentDef.  Even if a copy
-/// is consumed on a path to the dead-end, if the def stays live through to the
-/// dead-end, its lifetime must not be shrunk back from it (eventually we'll
-/// support shrinking it back to deinit barriers).
-///
-/// Example:
-///     %def is lexical
-///     %copy = copy_value %def
-///     consume %copy
-///     apply %foo() // deinit barrier
-///     // Must extend lifetime of %def up to this point per language rules.
-///     unreachable
-void CanonicalizeOSSALifetime::extendLexicalLivenessToDeadEnds() {
-  // TODO: OSSALifetimeCompletion: Once lifetimes are always complete, delete
-  //                               this method.
-  SmallVector<SILBasicBlock *, 32> directDiscoverdBlocks;
-  SSAPrunedLiveness directLiveness(function, &directDiscoverdBlocks);
-  directLiveness.initializeDef(getCurrentDef());
-  directLiveness.computeSimple();
-  OSSALifetimeCompletion::visitAvailabilityBoundary(
-      getCurrentDef(), directLiveness, [&](auto *unreachable, auto end) {
-        if (end == OSSALifetimeCompletion::LifetimeEnd::Boundary) {
-          recordUnreachableLifetimeEnd(unreachable);
-        }
-        unreachable->visitPriorInstructions([&](auto *inst) {
-          liveness->extendToNonUse(inst);
-          return true;
-        });
-      });
-}
-
-/// Extend liveness to the copy-extended availability boundary of currentDef.
-/// Prevents destroys from being inserted between borrows of (copies of) the
-/// def and dead-ends.
-///
-/// Example:
-///     %def need not be lexical
-///     %c = copy_value %def
-///     %sb = store_borrow %c to %addr
-///     // Must extend lifetime of %def up to this point.  Otherwise, a
-///     // destroy_value could be inserted within a borrow scope or interior
-///     // pointer use.
-///     unreachable
-void CanonicalizeOSSALifetime::extendLivenessToDeadEnds() {
-  // TODO: OSSALifetimeCompletion: Once lifetimes are always complete, delete
-  //                               this method.
-  SmallVector<SILBasicBlock *, 32> discoveredBlocks(this->discoveredBlocks);
-  SSAPrunedLiveness completeLiveness(*liveness, &discoveredBlocks);
-
-  for (auto destroy : destroys) {
-    if (liveness->isWithinBoundary(destroy, /*deadEndBlocks=*/nullptr))
-      continue;
-    completeLiveness.updateForUse(destroy, /*lifetimeEnding*/ true);
-  }
-
-  // Demote consuming uses within complete liveness to non-consuming uses.
-  //
-  // OSSALifetimeCompletion considers the lifetime of a single value.  Such
-  // lifetimes never continue beyond consumes.
-  std::optional<llvm::SmallPtrSet<SILInstruction *, 8>> lastUsers;
-  auto isConsumeOnBoundary = [&](SILInstruction *instruction) -> bool {
-    if (!lastUsers) {
-      // Avoid computing lastUsers if possible.
-      auto *function = getCurrentDef()->getFunction();
-      auto *deadEnds = deadEndBlocksAnalysis->get(function);
-      llvm::SmallVector<SILBasicBlock *, 8> completeConsumingBlocks(
-          consumingBlocks.getArrayRef());
-      for (auto &block : *function) {
-        if (!deadEnds->isDeadEnd(&block))
-          continue;
-        completeConsumingBlocks.push_back(&block);
-      }
-      PrunedLivenessBoundary boundary;
-      liveness->computeBoundary(boundary, completeConsumingBlocks);
-
-      lastUsers.emplace();
-      for (auto *lastUser : boundary.lastUsers) {
-        lastUsers->insert(lastUser);
-      }
-    }
-    return lastUsers->contains(instruction);
-  };
-  for (auto pair : liveness->getAllUsers()) {
-    if (!pair.second.isEnding())
-      continue;
-    auto *instruction = pair.first;
-    if (isConsumeOnBoundary(instruction))
-      continue;
-    // Demote instruction's lifetime-ending-ness to non-lifetime-ending.
-    completeLiveness.updateForUse(pair.first, /*lifetimeEnding=*/false);
-  }
-
-  OSSALifetimeCompletion::visitAvailabilityBoundary(
-      getCurrentDef(), completeLiveness, [&](auto *unreachable, auto end) {
-        if (end == OSSALifetimeCompletion::LifetimeEnd::Boundary) {
-          recordUnreachableLifetimeEnd(unreachable);
-        }
-        unreachable->visitPriorInstructions([&](auto *inst) {
-          liveness->extendToNonUse(inst);
-          return true;
-        });
-      });
-}
-
-void CanonicalizeOSSALifetime::extendLivenessToDeinitBarriers() {
-  SmallVector<SILInstruction *, 8> ends;
-  if (currentLexicalLifetimeEnds.size() > 0) {
-    visitExtendedUnconsumedBoundary(
-        currentLexicalLifetimeEnds,
-        [&ends](auto *instruction, auto lifetimeEnding) {
-          instruction->visitSubsequentInstructions([&](auto *next) {
-            ends.push_back(next);
-            return true;
-          });
-        });
-  } else {
-    for (auto destroy : destroys) {
-      if (destroy->getOperand(0) != getCurrentDef())
-        continue;
-      ends.push_back(destroy);
-    }
-  }
-
-  auto *def = getCurrentDef()->getDefiningInstruction();
-  using InitialBlocks = ArrayRef<SILBasicBlock *>;
-  auto *defBlock = getCurrentDef()->getParentBlock();
-  auto initialBlocks = defBlock ? InitialBlocks(defBlock) : InitialBlocks();
-  ReachableBarriers barriers;
-  findBarriersBackward(ends, initialBlocks, *getCurrentDef()->getFunction(),
-                       barriers, [&](auto *inst) {
-                         if (inst == def)
-                           return true;
-                         if (!isDeinitBarrier(inst, calleeAnalysis))
-                           return false;
-                         // For the most part, instructions that are deinit
-                         // barriers in the abstract are also deinit barriers
-                         // for the purposes of canonicalizing def's lifetime.
-                         //
-                         // There is an important exception: transferring an
-                         // owned lexical lifetime into a callee.  If the
-                         // instruction is a full apply which consumes def,
-                         // then it isn't a deinit barrier.  Keep looking for
-                         // barriers above it.
-                         auto apply = FullApplySite::isa(inst);
-                         if (!apply)
-                           return true;
-                         return liveness->isInterestingUser(inst) !=
-                                PrunedLiveness::IsInterestingUser::
-                                    LifetimeEndingUse;
-                       });
-  for (auto *barrier : barriers.instructions) {
-    liveness->extendToNonUse(barrier);
-  }
-  for (auto *barrier : barriers.phis) {
-    for (auto *predecessor : barrier->getPredecessorBlocks()) {
-      liveness->extendToNonUse(predecessor->getTerminator());
-    }
-  }
-  for (auto *edge : barriers.edges) {
-    auto *predecessor = edge->getSinglePredecessorBlock();
-    assert(predecessor);
-    liveness->extendToNonUse(&predecessor->back());
-  }
-  // Ignore barriers.initialBlocks.  If the collection is non-empty, it
-  // contains the def-block.  Its presence means that no barriers were found
-  // between lifetime ends and def.  In that case, no new instructions need to
-  // be added to liveness.
-}
-
-// Return true if \p inst is an end_access whose access scope overlaps the end
-// of the pruned live range. This means that a hoisted destroy might execute
-// within the access scope which previously executed outside the access scope.
-//
-// Not overlapping (ignored):
-//
-//     %def
-//     use %def     // pruned liveness ends here
-//     begin_access // access scope unrelated to def
-//     end_access
-//
-// Overlapping (must extend pruned liveness):
-//
-//     %def
-//     begin_access // access scope unrelated to def
-//     use %def     // pruned liveness ends here
-//     end_access
-//
-// Overlapping (must extend pruned liveness):
-//
-//     begin_access // access scope unrelated to def
-//     %def
-//     use %def     // pruned liveness ends here
-//     end_access
-//
-bool CanonicalizeOSSALifetime::
-endsAccessOverlappingPrunedBoundary(SILInstruction *inst) {
-  if (isa<EndUnpairedAccessInst>(inst)) {
-    return true;
-  }
-  auto *endAccess = dyn_cast<EndAccessInst>(inst);
-  if (!endAccess) {
-    return false;
-  }
-  auto *beginAccess = endAccess->getBeginAccess();
-  SILBasicBlock *beginBB = beginAccess->getParent();
-  switch (liveness->getBlockLiveness(beginBB)) {
-  case PrunedLiveBlocks::LiveOut:
-    // Found partial overlap of the form:
-    //     currentDef
-    //     beginAccess
-    //     br...
-    //   bb...
-    //     use
-    //     endAccess
-    return true;
-  case PrunedLiveBlocks::LiveWithin:
-    // Check for partial overlap of this form where beginAccess and the last use
-    // are in the same block:
-    //     currentDef
-    //     beginAccess
-    //     use
-    //     endAccess
-    if (std::find_if(std::next(beginAccess->getIterator()), beginBB->end(),
-                     [this](SILInstruction &nextInst) {
-                       return liveness->isInterestingUser(&nextInst)
-                              != PrunedLiveness::NonUser;
-                     })
-        != beginBB->end()) {
-      // An interesting use after the beginAccess means overlap.
-      return true;
-    }
-    return false;
-  case PrunedLiveBlocks::Dead:
-    // Check for partial overlap of this form where beginAccess and currentDef
-    // are in different blocks:
-    //     beginAccess
-    //     br...
-    //  bb...
-    //     currentDef
-    //     endAccess
-    //
-    // Since beginAccess is not within the canonical live range, its access
-    // scope overlaps only if there is a path from beginAccess to currentDef
-    // that does not pass through endAccess. endAccess is dominated by
-    // both currentDef and begin_access. Therefore, such a path only exists if
-    // beginAccess dominates currentDef.
-    return domTree->properlyDominates(beginAccess->getParent(),
-                                      getCurrentDef()->getParentBlock());
-  }
-  llvm_unreachable("covered switch");
-}
-
-// Find all overlapping access scopes and extend pruned liveness to cover them:
-//
-// This may also unnecessarily, but conservatively extend liveness over some
-// originally overlapping access, such as:
-//
-//     begin_access // access scope unrelated to def
-//     %def
-//     use %def
-//     destroy %def
-//     end_access
-//
-// Or:
-//
-//     %def
-//     begin_access // access scope unrelated to def
-//     use %def
-//     destroy %def
-//     end_access
-//
-// To minimize unnecessary lifetime extension, only search for end_access
-// within dead blocks that are backward reachable from an original destroy.
-//
-// Note that lifetime extension is iterative because adding a new liveness use
-// may create new overlapping access scopes. This can happen because there is no
-// guarantee of strict stack discipline across unrelated access. For example:
-//
-//     %def
-//     begin_access A
-//     use %def        // Initial pruned lifetime boundary
-//     begin_access B
-//     end_access A    // Lifetime boundary after first extension
-//     end_access B    // Lifetime boundary after second extension
-//     destroy %def
-//
-// If the lifetime extension did not iterate, then def would be destroyed within
-// B's access scope when originally it was destroyed outside that scope.
-void CanonicalizeOSSALifetime::extendLivenessThroughOverlappingAccess() {
-  this->accessBlocks = accessBlockAnalysis->get(getCurrentDef()->getFunction());
-
-  // Visit each original consuming use or destroy as the starting point for a
-  // backward CFG traversal. This traversal must only visit blocks within the
-  // original extended lifetime.
-  bool changed = true;
-  while (changed) {
-    changed = false;
-    // The blocks in which we may have to extend liveness over access scopes.
-    //
-    // It must be populated first so that we can test membership during the loop
-    // (see findLastConsume).
-    BasicBlockSetVector blocksToVisit(getCurrentDef()->getFunction());
-    for (auto *block : consumingBlocks) {
-      blocksToVisit.insert(block);
-    }
-    for (auto iterator = blocksToVisit.begin(); iterator != blocksToVisit.end();
-         ++iterator) {
-      auto *bb = *iterator;
-      // If the block isn't dead, then we won't need to extend liveness within
-      // any of its predecessors (though we may within it).
-      if (liveness->getBlockLiveness(bb) != PrunedLiveBlocks::Dead)
-        continue;
-      // Continue searching upward to find the pruned liveness boundary.
-      for (auto *predBB : bb->getPredecessorBlocks()) {
-        blocksToVisit.insert(predBB);
-      }
-    }
-    for (auto *bb : blocksToVisit) {
-      auto blockLiveness = liveness->getBlockLiveness(bb);
-      // Ignore blocks within pruned liveness.
-      if (blockLiveness == PrunedLiveBlocks::LiveOut) {
-        continue;
-      }
-      if (blockLiveness == PrunedLiveBlocks::Dead) {
-        // Otherwise, ignore dead blocks with no nonlocal end_access.
-        if (!accessBlocks->containsNonLocalEndAccess(bb)) {
-          continue;
-        }
-      }
-      bool blockHasUse = (blockLiveness == PrunedLiveBlocks::LiveWithin);
-      // Find the latest partially overlapping access scope, if one exists:
-      //     use %def // pruned liveness ends here
-      //     end_access
-
-      // Whether to look for the last consume in the block.
-      //
-      // We need to avoid extending liveness over end_accesses that occur after
-      // original liveness ended.
-      bool findLastConsume =
-          consumingBlocks.contains(bb)
-          && llvm::none_of(bb->getSuccessorBlocks(), [&](auto *successor) {
-               return blocksToVisit.contains(successor)
-                      && liveness->getBlockLiveness(successor)
-                             == PrunedLiveBlocks::Dead;
-             });
-      for (auto &inst : llvm::reverse(*bb)) {
-        if (findLastConsume) {
-          findLastConsume = !destroys.contains(&inst);
-          continue;
-        }
-        // Stop at the latest use. An earlier end_access does not overlap.
-        if (blockHasUse
-            && liveness->isInterestingUser(&inst) != PrunedLiveness::NonUser) {
-          break;
-        }
-        if (endsAccessOverlappingPrunedBoundary(&inst)) {
-          liveness->extendToNonUse(&inst);
-          changed = true;
-          break;
-        }
-      }
-      // If liveness changed, might as well restart CFG traversal.
-      if (changed) {
-        break;
-      }
-    }
-  }
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: Step 2. Find the "original" (unextended) boundary determined by the
-//               liveness built up in step 1.
-//===----------------------------------------------------------------------===//
-
-void CanonicalizeOSSALifetime::findOriginalBoundary(
-    PrunedLivenessBoundary &boundary) {
-  assert(boundary.lastUsers.size() == 0 && boundary.boundaryEdges.size() == 0 &&
-         boundary.deadDefs.size() == 0);
-  liveness->computeBoundary(boundary, consumingBlocks.getArrayRef());
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: Step 3. (Optional) Maximize lifetimes.
-//===----------------------------------------------------------------------===//
-
-/// At -Onone, there are some conflicting goals:
-/// On the one hand: good debugging experience.
-/// (1) do not shorten value's lifetime
-/// On the other: demonstrate semantics.
-/// (2) consume value at same places it will be consumed at -O
-/// (3) ensure there are no more copies than there would be at -O
-///
-/// (2) and (3) are equivalent--extra (compared to -O) copies arise from failing
-/// to end lifetimes at consuming uses (which then need their own copies).
-///
-/// We achieve (2) and (3) always.  We achieve (1) where possible.
-///
-/// Conceptually, the strategy is the following:
-/// - Collect the blocks in which the value was live before canonicalization.
-///   These are the "original" live blocks (originalLiveBlocks).
-///   [Color these blocks green.]
-/// - From within that collection, collect the blocks which contain a _final_
-///   consuming, non-destroy use, and their iterative successors.
-///   These are the "consumed" blocks (consumedAtExitBlocks).
-///   [Color these blocks red.]
-/// - Extend liveness down to the boundary between originalLiveBlocks and
-///   consumedAtExitBlocks blocks.
-///   [Extend liveness down to the boundary between green blocks and red.]
-/// - In particular, in regions of originalLiveBlocks which have no boundary
-///   with consumedAtExitBlocks, liveness should be extended to its original
-///   extent.
-///   [Extend liveness down to the boundary between green blocks and uncolored.]
-void CanonicalizeOSSALifetime::visitExtendedUnconsumedBoundary(
-    ArrayRef<SILInstruction *> consumes,
-    llvm::function_ref<void(SILInstruction *, PrunedLiveness::LifetimeEnding)>
-        visitor) {
-  auto currentDef = getCurrentDef();
-
-#ifndef NDEBUG
-  for (auto *consume : consumes) {
-    assert(!liveness->isWithinBoundary(consume, /*deadEndBlocks=*/nullptr));
-  }
-#endif
-
-  // First, collect the blocks that were _originally_ live.  We can't use
-  // liveness here because it doesn't include blocks that occur before a
-  // destroy_value.
-  BasicBlockSet originalLiveBlocks(currentDef->getFunction());
-  {
-    // Some of the work here was already done by computeCanonicalLiveness.
-    // Specifically, it already discovered all blocks containing (transitive)
-    // uses and blocks that appear between them and the def.
-    //
-    // Seed the set with what it already discovered.
-    for (auto *discoveredBlock : liveness->getDiscoveredBlocks())
-      originalLiveBlocks.insert(discoveredBlock);
-
-    // Start the walk from the consuming blocks (which includes destroys as well
-    // as the other consuming uses).
-    BasicBlockWorklist worklist(currentDef->getFunction());
-    for (auto *consumingBlock : consumingBlocks) {
-      worklist.push(consumingBlock);
-    }
-
-    // Walk backwards from consuming blocks.
-    while (auto *block = worklist.pop()) {
-      if (!originalLiveBlocks.insert(block))
-        continue;
-      for (auto *predecessor : block->getPredecessorBlocks()) {
-        // If the block was discovered by liveness, we already added it to the
-        // set.
-        if (originalLiveBlocks.contains(predecessor))
-          continue;
-        worklist.pushIfNotVisited(predecessor);
-      }
-    }
-  }
-
-  // Second, collect the blocks which contain a _final_ consuming use and their
-  // iterative successors within the originalLiveBlocks.
-  BasicBlockSet consumedAtExitBlocks(currentDef->getFunction());
-  // The subset of consumedAtExitBlocks which do not contain a _final_ consuming
-  // use, i.e. the subset that is dead.
-  StackList<SILBasicBlock *> consumedAtEntryBlocks(currentDef->getFunction());
-  {
-    // Start the forward walk from blocks which contain _final_ non-destroy
-    // consumes. These are just the instructions on the boundary which aren't
-    // destroys.
-    BasicBlockWorklist worklist(currentDef->getFunction());
-    for (auto *instruction : consumes) {
-      if (destroys.contains(instruction))
-        continue;
-      if (liveness->isInterestingUser(instruction)
-          != PrunedLiveness::IsInterestingUser::LifetimeEndingUse)
-        continue;
-      worklist.push(instruction->getParent());
-    }
-    while (auto *block = worklist.pop()) {
-      consumedAtExitBlocks.insert(block);
-      for (auto *successor : block->getSuccessorBlocks()) {
-        if (!originalLiveBlocks.contains(successor))
-          continue;
-        worklist.pushIfNotVisited(successor);
-        consumedAtEntryBlocks.push_back(successor);
-      }
-    }
-  }
-
-  // Third, find the blocks on the boundary between the originalLiveBlocks
-  // blocks and the consumedAtEntryBlocks blocks.  Extend liveness "to the end"
-  // of these blocks.
-  for (auto *block : consumedAtEntryBlocks) {
-    for (auto *predecessor : block->getPredecessorBlocks()) {
-      if (consumedAtExitBlocks.contains(predecessor))
-        continue;
-      // Add "the instruction(s) before the terminator" of the predecessor to
-      // liveness.
-      predecessor->getTerminator()->visitPriorInstructions([&](auto *inst) {
-        visitor(inst, PrunedLiveness::LifetimeEnding::Value::NonUse);
-        return true;
-      });
-    }
-  }
-
-  // Finally, preserve the destroys which weren't in the consumed region in
-  // place: hoisting such destroys would not avoid copies.
-  for (auto *destroy : destroys) {
-    auto *block = destroy->getParent();
-    // If the destroy is in a consumed block or a final consuming block,
-    // hoisting it would avoid a copy.
-    if (consumedAtExitBlocks.contains(block))
-      continue;
-    visitor(destroy, PrunedLiveness::LifetimeEnding::Value::Ending);
-  }
-}
-
-void CanonicalizeOSSALifetime::extendUnconsumedLiveness(
-    PrunedLivenessBoundary const &boundary) {
-  visitExtendedUnconsumedBoundary(
-      boundary.lastUsers, [&](auto *instruction, auto lifetimeEnding) {
-        liveness->updateForUse(instruction, lifetimeEnding);
-      });
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: Step 4. Extend the "original" boundary from step 2 up to destroys that
-//               aren't separated from it by "interesting" instructions.
-//===----------------------------------------------------------------------===//
-
-namespace {
-/// Extends the boundary from PrunedLiveness down to preexisting destroys of the
-/// def which aren't separated from the original boundary by "interesting"
-/// instructions.
-///
-/// The motivation for extending the boundary is to avoid "churning" when
-/// iterating to a fixed point by canonicalizing the lifetimes of several
-/// values with overlapping live ranges and failing to find a fixed point
-/// because their destroys are repeatedly hoisted over one another.
-class ExtendBoundaryToDestroys final {
-  using InstructionPredicate = llvm::function_ref<bool(SILInstruction *)>;
-  SSAPrunedLiveness &liveness;
-  PrunedLivenessBoundary const &originalBoundary;
-  SILValue currentDef;
-  BasicBlockSet seenMergePoints;
-  InstructionPredicate isDestroy;
-
-public:
-  ExtendBoundaryToDestroys(SSAPrunedLiveness &liveness,
-                           PrunedLivenessBoundary const &originalBoundary,
-                           SILValue currentDef, InstructionPredicate isDestroy)
-      : liveness(liveness), originalBoundary(originalBoundary),
-        currentDef(currentDef), seenMergePoints(currentDef->getFunction()),
-        isDestroy(isDestroy){};
-  ExtendBoundaryToDestroys(ExtendBoundaryToDestroys const &) = delete;
-  ExtendBoundaryToDestroys &
-  operator=(ExtendBoundaryToDestroys const &) = delete;
-
-  /// Compute the extended boundary by walking out from the original boundary
-  /// (from PrunedLiveness::computeBoundary) down to any destroys that appear
-  /// later but which aren't separated from the original boundary by
-  /// "interesting" users.
-  void extend(PrunedLivenessBoundary &boundary) {
-    for (auto *def : originalBoundary.deadDefs) {
-      extendBoundaryFromDef(def, boundary);
-    }
-    for (auto *destination : originalBoundary.boundaryEdges) {
-      extendBoundaryFromBoundaryEdge(destination, boundary);
-    }
-    for (auto *user : originalBoundary.lastUsers) {
-      extendBoundaryFromUser(user, boundary);
-    }
-  }
-
-  /// Look past ignoreable instructions to find the _last_ destroy after the
-  /// specified instruction that destroys \p def.
-  static DestroyValueInst *findDestroyAfter(SILInstruction *previous,
-                                            SILValue def,
-                                            InstructionPredicate isDestroy) {
-    DestroyValueInst *retval = nullptr;
-    for (auto *instruction = previous->getNextInstruction(); instruction;
-         instruction = instruction->getNextInstruction()) {
-      if (!CanonicalizeOSSALifetime::ignoredByDestroyHoisting(
-              instruction->getKind()))
-        break;
-      if (isDestroy(instruction))
-        retval = cast<DestroyValueInst>(instruction);
-    }
-    return retval;
-  }
-
-  /// Look past ignoreable instructions to find the _last_ destroy at or after
-  /// the specified instruction that destroys \p def.
-  static DestroyValueInst *
-  findDestroyAtOrAfter(SILInstruction *start, SILValue def,
-                       InstructionPredicate isDestroy) {
-    if (isDestroy(start))
-      return cast<DestroyValueInst>(start);
-    return findDestroyAfter(start, def, isDestroy);
-  }
-
-  /// Look past ignoreable instructions to find the _first_ destroy in \p
-  /// destination that destroys \p def and isn't separated from the beginning
-  /// by "interesting" instructions.
-  static DestroyValueInst *
-  findDestroyFromBlockBegin(SILBasicBlock *destination, SILValue def,
-                            InstructionPredicate isDestroy) {
-    return findDestroyAtOrAfter(&*destination->begin(), def, isDestroy);
-  }
-
-private:
-  /// Compute the points on the extended boundary found by walking forward from
-  /// the dead def (starting either with the top of the block in the case of a
-  /// dead arg or the next instruction in the case of an instruction) down to
-  /// any destroys that appear later but which aren't separated from the
-  /// original boundary by "interesting" users.
-  ///
-  /// If a destroy is found, it becomes a last user.  Otherwise, the boundary
-  /// stays in place and \p def remains a dead def.
-  void extendBoundaryFromDef(SILNode *def, PrunedLivenessBoundary &boundary) {
-    if (auto *arg = dyn_cast<SILArgument>(def)) {
-      if (auto *dvi = findDestroyFromBlockBegin(arg->getParent(), currentDef,
-                                                isDestroy)) {
-        boundary.lastUsers.push_back(dvi);
-        return;
-      }
-    } else {
-      if (auto *dvi = findDestroyAfter(cast<SILInstruction>(def), currentDef,
-                                       isDestroy)) {
-        boundary.lastUsers.push_back(dvi);
-        return;
-      }
-    }
-    boundary.deadDefs.push_back(def);
-  }
-
-  /// Compute the points on the extended boundary found by walking down from the
-  /// boundary edge in the original boundary (uniquely determined by the
-  /// specified destination edge) down to any destroys that appear later but
-  /// which aren't separated from the original boundary by "interesting" users.
-  ///
-  /// If a destroy is found, it becomes a last user.  Otherwise, the boundary
-  /// stays in place and \p destination remains a boundary edge.
-  void extendBoundaryFromBoundaryEdge(SILBasicBlock *destination,
-                                      PrunedLivenessBoundary &boundary) {
-    if (auto *dvi =
-            findDestroyFromBlockBegin(destination, currentDef, isDestroy)) {
-      boundary.lastUsers.push_back(dvi);
-    } else {
-      boundary.boundaryEdges.push_back(destination);
-    }
-  }
-
-  /// Compute the points on the extended boundary found by walking down from the
-  /// specified instruction in the original boundary down to any destroys that
-  /// appear later but which aren't separated from the original boundary by
-  /// "interesting" users.
-  ///
-  /// If the user is consuming, the boundary remains in place.
-  ///
-  /// If the user is a terminator, see extendBoundaryFromTerminator.
-  ///
-  /// If a destroy is found after the (non-consuming, non-terminator) \p user,
-  /// it becomes a last user.  Otherwise, the boundary stays in place and \p
-  /// user remains a last user.
-  void extendBoundaryFromUser(SILInstruction *user,
-                              PrunedLivenessBoundary &boundary) {
-    if (isDestroy(user)) {
-      auto *dvi = cast<DestroyValueInst>(user);
-      auto *existingDestroy = findDestroyAtOrAfter(dvi, currentDef, isDestroy);
-      assert(existingDestroy && "couldn't find a destroy at or after one!?");
-      boundary.lastUsers.push_back(existingDestroy);
-      return;
-    }
-    switch (liveness.isInterestingUser(user)) {
-    case PrunedLiveness::IsInterestingUser::LifetimeEndingUse:
-      // Even if we saw a destroy after this consuming use, we don't want to
-      // add it to the boundary.  We will rewrite copies so that this user is
-      // the final consuming user on this path.
-      boundary.lastUsers.push_back(user);
-      return;
-    case PrunedLiveness::IsInterestingUser::NonLifetimeEndingUse:
-    case PrunedLiveness::IsInterestingUser::NonUser:
-      if (auto *terminator = dyn_cast<TermInst>(user)) {
-        extendBoundaryFromTerminator(terminator, boundary);
-        return;
-      }
-      if (auto *existingDestroy =
-              findDestroyAfter(user, currentDef, isDestroy)) {
-        boundary.lastUsers.push_back(existingDestroy);
-        return;
-      }
-      boundary.lastUsers.push_back(user);
-    }
-  }
-
-  /// Compute the points on the extended boundary by walking into \p user's
-  /// parent's successors and looking for destroys.
-  ///
-  /// If any destroys are found, they become last users and all other successors
-  /// (which lack destroys) become boundary edges.  If no destroys are found,
-  /// the boundary stays in place and \p user remains a last user.
-  void extendBoundaryFromTerminator(TermInst *user,
-                                    PrunedLivenessBoundary &boundary) {
-    auto *block = user->getParent();
-    // Record the successors at the beginning of which we didn't find destroys.
-    // If we found a destroy at the beginning of any other successor, then all
-    // the other edges become boundary edges.
-    SmallVector<SILBasicBlock *, 4> successorsWithoutDestroys;
-    bool foundDestroy = false;
-    for (auto *successor : block->getSuccessorBlocks()) {
-      // If multiple terminators were live and had the same successor, only
-      // record the boundary corresponding to that destination block once.
-      if (!seenMergePoints.insert(successor)) {
-        // Thanks to the lack of critical edges, having seen this successor
-        // before means it has multiple predecessors, so this must be \p block's
-        // unique successor.
-        assert(block->getSingleSuccessorBlock() == successor);
-        // When this merge point was encountered the first time, a
-        // destroy_value was sought from its top.  If one was found, it was
-        // added to the boundary. If no destroy_value was found, _that_ user
-        // (i.e. the one on behalf of which extendBoundaryFromTerminator was
-        // called which inserted successor into seenMergePoints) was added to
-        // the boundary.
-        //
-        // This time, if a destroy was found, it's already in the boundary.  If
-        // no destroy was found, though, _this_ user must be added to the
-        // boundary.
-        foundDestroy =
-            findDestroyFromBlockBegin(successor, currentDef, isDestroy);
-        continue;
-      }
-      if (auto *dvi =
-              findDestroyFromBlockBegin(successor, currentDef, isDestroy)) {
-        boundary.lastUsers.push_back(dvi);
-        foundDestroy = true;
-      } else {
-        successorsWithoutDestroys.push_back(successor);
-      }
-    }
-    if (foundDestroy) {
-      // If we found a destroy in any successor, then every block at the
-      // beginning of which we didn't find a destroy becomes a boundary edge.
-      for (auto *successor : successorsWithoutDestroys) {
-        boundary.boundaryEdges.push_back(successor);
-      }
-    } else {
-      boundary.lastUsers.push_back(user);
-    }
-  }
-};
-} // anonymous namespace
-
-void CanonicalizeOSSALifetime::findExtendedBoundary(
-    PrunedLivenessBoundary const &originalBoundary,
-    PrunedLivenessBoundary &boundary) {
-  assert(boundary.lastUsers.size() == 0 && boundary.boundaryEdges.size() == 0 &&
-         boundary.deadDefs.size() == 0);
-  auto isDestroy = [&](auto *inst) { return destroys.contains(inst); };
-  ExtendBoundaryToDestroys extender(*liveness, originalBoundary,
-                                    getCurrentDef(), isDestroy);
-  extender.extend(boundary);
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: Step 5. Insert destroys onto the boundary found in step 3 where needed.
-//===----------------------------------------------------------------------===//
-
-/// Create a new destroy_value instruction before the specified instruction and
-/// record it as a final consume.
-static void
-insertDestroyBeforeInstruction(SILInstruction *nextInstruction,
-                               SILValue currentDef, IsDeadEnd_t isDeadEnd,
-                               CanonicalOSSAConsumeInfo &consumes,
-                               SmallVectorImpl<DestroyValueInst *> &destroys,
-                               InstModCallbacks &callbacks) {
-  // OSSALifetimeCompletion: This conditional clause can be deleted with
-  // complete lifetimes.
-  if (consumes.isUnreachableLifetimeEnd(nextInstruction)) {
-    // Don't create a destroy_value if the next instruction is an unreachable
-    // (or a terminator on the availability boundary of the dead-end region
-    // starting from the non-lifetime-ending boundary of `currentDef`).
-    //
-    // If there was a destroy here already, it would be reused.  Avoids
-    // creating an explicit destroy of a value which might have an unclosed
-    // borrow scope.  Doing so would result in
-    //
-    //     somewhere:
-    //       %def
-    //       %borrow = begin_borrow ...
-    //
-    //     die:
-    //       destroy_value %def
-    //       unreachable
-    //
-    // which is invalid (although the verifier doesn't catch
-    // it--rdar://115850528) because there must be an `end_borrow %borrow`
-    // before the destroy_value.
-    return;
-  }
-  SILBuilderWithScope builder(nextInstruction);
-  auto loc =
-      RegularLocation::getAutoGeneratedLocation(nextInstruction->getLoc());
-  auto *dvi =
-      builder.createDestroyValue(loc, currentDef, DontPoisonRefs, isDeadEnd);
-  callbacks.createdNewInst(dvi);
-  consumes.recordFinalConsume(dvi);
-  ++NumDestroysGenerated;
-  destroys.push_back(dvi);
-}
-
-/// Whether a destroy created at \p inst should be marked [dead_end].
-///
-/// It should be if
-/// (1) \p inst is itself in a dead-end region
-/// (2) all destroys after \p inst are [dead_end]
-static IsDeadEnd_t
-isDeadEndDestroy(SILInstruction *inst,
-                 SmallPtrSetVector<SILInstruction *, 8> const &destroys,
-                 BasicBlockSet &semanticDestroysBlocks,
-                 DeadEndBlocks *deadEnds) {
-  auto *parent = inst->getParent();
-  if (!deadEnds->isDeadEnd(parent)) {
-    // Only destroys in dead-ends can be non-meaningful (aka "dead end").
-    return IsntDeadEnd;
-  }
-  if (semanticDestroysBlocks.contains(parent)) {
-    // `parent` has a semantic destroy somewhere.  Is it after `inst`?
-    for (auto *i = inst; i; i = i->getNextInstruction()) {
-      if (!destroys.contains(i)) {
-        continue;
-      }
-      auto *dvi = cast<DestroyValueInst>(i);
-      if (!dvi->isDeadEnd()) {
-        // Some subsequent destroy within `parent` was meaningful, so one
-        // created at `inst` must be too.
-        return IsntDeadEnd;
-      }
-    }
-  }
-  // Walk the portion of the dead-end region after `parent` to check that all
-  // destroys are non-meaningful.
-  BasicBlockWorklist worklist(inst->getFunction());
-  for (auto *successor : parent->getSuccessorBlocks()) {
-    worklist.push(successor);
-  }
-  while (auto *block = worklist.pop()) {
-    assert(deadEnds->isDeadEnd(block));
-    if (semanticDestroysBlocks.contains(block)) {
-      // Some subsequent destroy was meaningful, so one created at `inst`
-      // must be too.
-      return IsntDeadEnd;
-    }
-    for (auto *successor : block->getSuccessorBlocks()) {
-      worklist.pushIfNotVisited(successor);
-    }
-  }
-  return IsDeadEnd;
-}
-
-/// Inserts destroys along the boundary where needed and records all final
-/// consuming uses.
-///
-/// Observations:
-/// - currentDef must be postdominated by some subset of its
-///   consuming uses, including destroys on all return paths.
-/// - The postdominating consumes cannot be within nested loops.
-/// - Any blocks in nested loops are now marked LiveOut.
-void CanonicalizeOSSALifetime::insertDestroysOnBoundary(
-    PrunedLivenessBoundary const &boundary,
-    SmallVectorImpl<DestroyValueInst *> &newDestroys) {
-  BasicBlockSet semanticDestroyBlocks(getCurrentDef()->getFunction());
-  for (auto *destroy : destroys) {
-    if (!cast<DestroyValueInst>(destroy)->isDeadEnd()) {
-      semanticDestroyBlocks.insert(destroy->getParent());
-    }
-  }
-  auto isDeadEnd = [&semanticDestroyBlocks,
-                    this](SILInstruction *inst) -> IsDeadEnd_t {
-    return isDeadEndDestroy(
-        inst, destroys, semanticDestroyBlocks,
-        deadEndBlocksAnalysis->get(getCurrentDef()->getFunction()));
-  };
-  BasicBlockSet seenMergePoints(getCurrentDef()->getFunction());
-  for (auto *instruction : boundary.lastUsers) {
-    if (destroys.contains(instruction)) {
-      consumes.recordFinalConsume(instruction);
-      continue;
-    }
-    switch (liveness->isInterestingUser(instruction)) {
-    case PrunedLiveness::IsInterestingUser::LifetimeEndingUse:
-      consumes.recordFinalConsume(instruction);
-      continue;
-    case PrunedLiveness::IsInterestingUser::NonLifetimeEndingUse:
-    case PrunedLiveness::IsInterestingUser::NonUser:
-      if (isa<TermInst>(instruction)) {
-        auto *block = instruction->getParent();
-        for (auto *successor : block->getSuccessorBlocks()) {
-          if (!seenMergePoints.insert(successor)) {
-            assert(block->getSingleSuccessorBlock() == successor);
-            continue;
-          }
-          auto *insertionPoint = &*successor->begin();
-          insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
-                                         isDeadEnd(insertionPoint), consumes,
-                                         newDestroys, getCallbacks());
-          LLVM_DEBUG(llvm::dbgs() << "  Destroy after terminator "
-                                  << *instruction << " at beginning of ";
-                     successor->printID(llvm::dbgs(), false);
-                     llvm::dbgs() << "\n";);
-        }
-        continue;
-      }
-      auto *insertionPoint = instruction->getNextInstruction();
-      insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
-                                     isDeadEnd(insertionPoint), consumes,
-                                     newDestroys, getCallbacks());
-      LLVM_DEBUG(llvm::dbgs()
-                 << "  Destroy at last use " << insertionPoint << "\n");
-      continue;
-    }
-  }
-  for (auto *edgeDestination : boundary.boundaryEdges) {
-    auto *insertionPoint = &*edgeDestination->begin();
-    insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
-                                   isDeadEnd(insertionPoint), consumes,
-                                   newDestroys, getCallbacks());
-    LLVM_DEBUG(llvm::dbgs() << "  Destroy on edge " << edgeDestination << "\n");
-  }
-  for (auto *def : boundary.deadDefs) {
-    if (auto *arg = dyn_cast<SILArgument>(def)) {
-      auto *insertionPoint = &*arg->getParent()->begin();
-      insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
-                                     isDeadEnd(insertionPoint), consumes,
-                                     newDestroys, getCallbacks());
-      LLVM_DEBUG(llvm::dbgs()
-                 << "  Destroy after dead def arg " << arg << "\n");
-    } else {
-      auto *instruction = cast<SILInstruction>(def);
-      auto *insertionPoint = instruction->getNextInstruction();
-      assert(insertionPoint && "def instruction was a terminator?!");
-      insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
-                                     isDeadEnd(insertionPoint), consumes,
-                                     newDestroys, getCallbacks());
-      LLVM_DEBUG(llvm::dbgs()
-                 << "  Destroy after dead def inst " << instruction << "\n");
-    }
-  }
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: Step 6. Rewrite copies and destroys
-//===----------------------------------------------------------------------===//
-
-/// The lifetime extends beyond given consuming use. Copy the value.
-///
-/// This can set the operand value, but cannot invalidate the use iterator.
-void swift::copyLiveUse(Operand *use, InstModCallbacks &instModCallbacks) {
-  SILInstruction *user = use->getUser();
-  SILBuilderWithScope builder(user->getIterator());
-
-  auto loc = RegularLocation::getAutoGeneratedLocation(user->getLoc());
-  auto *copy = builder.createCopyValue(loc, use->get());
-  instModCallbacks.createdNewInst(copy);
-  use->set(copy);
-
-  ++NumCopiesGenerated;
-  LLVM_DEBUG(llvm::dbgs() << "  Copying at last use " << *copy);
-}
-
-/// Revisit the def-use chain of currentDef. Mark unneeded original
-/// copies and destroys for deletion. Insert new copies for interior uses that
-/// require ownership of the used operand.
-void CanonicalizeOSSALifetime::rewriteCopies(
-    SmallVectorImpl<DestroyValueInst *> const &newDestroys) {
-  assert(getCurrentDef()->getOwnershipKind() == OwnershipKind::Owned);
-
-  // Shadow discoveredDefs in order to constrain its uses.
-  const auto &discoveredDefs = this->discoveredDefs;
-
-  InstructionSetVector instsToDelete(getCurrentDef()->getFunction());
-
-  // Visit each operand in the def-use chain.
-  //
-  // Return true if the operand can use the current definition. Return false if
-  // it requires a copy.
-  auto visitUse = [&](Operand *use) {
-    auto *user = use->getUser();
-    if (destroys.contains(user)) {
-      auto *destroy = cast<DestroyValueInst>(user);
-      // If this destroy was marked as a final destroy, ignore it; otherwise,
-      // delete it.
-      if (!consumes.claimConsume(destroy)) {
-        instsToDelete.insert(destroy);
-        LLVM_DEBUG(llvm::dbgs() << "  Removing " << *destroy);
-        ++NumDestroysEliminated;
-      } else if (pruneDebugMode) {
-        // If this destroy was marked as a final destroy, add it to liveness so
-        // that we don't delete any debug instructions that occur before it.
-        // (Only relevant in pruneDebugMode).
-        liveness->updateForUse(destroy, /*lifetimeEnding*/ true);
-      }
-      return true;
-    }
-
-    // Nonconsuming uses do not need copies and cannot be marked as destroys.
-    // A lifetime-ending use here must be a consume because EndBorrow/Reborrow
-    // uses have been filtered out.
-    if (!use->isLifetimeEnding())
-      return true;
-
-    // If this use was not marked as a final destroy *or* this is not the first
-    // consumed operand we visited, then it needs a copy.
-    if (!consumes.claimConsume(user)) {
-      return false;
-    }
-
-    return true;
-  };
-
-  // Perform a def-use traversal, visiting each use operand.
-  for (auto def : discoveredDefs) {
-    switch (def.kind) {
-    case Def::BorrowedFrom:
-    case Def::Reborrow:
-      // Direct uses of these defs never need to be rewritten.  Being guaranteed
-      // values, none of their direct uses consume an owned value.
-      assert(def.value->getOwnershipKind() == OwnershipKind::Guaranteed);
-      break;
-    case Def::Root: {
-      SILValue value = def.value;
-      for (auto useIter = value->use_begin(), endIter = value->use_end();
-           useIter != endIter;) {
-        Operand *use = *useIter++;
-        if (!visitUse(use)) {
-          copyLiveUse(use, getCallbacks());
-        }
-      }
-      break;
-    }
-    case Def::Copy: {
-      SILValue value = def.value;
-      CopyValueInst *srcCopy = cast<CopyValueInst>(value);
-      // Recurse through copies while replacing their uses.
-      Operand *reusedCopyOp = nullptr;
-      for (auto useIter = srcCopy->use_begin();
-           useIter != srcCopy->use_end();) {
-        Operand *use = *useIter++;
-        if (!visitUse(use)) {
-          if (!reusedCopyOp && srcCopy->getParent() == use->getParentBlock()) {
-            reusedCopyOp = use;
-          } else {
-            copyLiveUse(use, getCallbacks());
-          }
-        }
-      }
-      if (!(reusedCopyOp && srcCopy->hasOneUse())) {
-        getCallbacks().replaceValueUsesWith(srcCopy, srcCopy->getOperand());
-        if (reusedCopyOp) {
-          reusedCopyOp->set(srcCopy);
-        } else {
-          if (instsToDelete.insert(srcCopy)) {
-            LLVM_DEBUG(llvm::dbgs() << "  Removing " << *srcCopy);
-            ++NumCopiesAndMovesEliminated;
-          }
-        }
-      }
-      break;
-    }
-    }
-  }
-  assert(!consumes.hasUnclaimedConsumes());
-
-  if (pruneDebugMode) {
-    for (auto *destroy : newDestroys) {
-      liveness->updateForUse(destroy, /*lifetimeEnding=*/true);
-    }
-    for (auto *dvi : debugValues) {
-      if (liveness->isWithinBoundary(
-              dvi,
-              deadEndBlocksAnalysis->get(getCurrentDef()->getFunction()))) {
-        continue;
-      }
-      LLVM_DEBUG(llvm::dbgs() << "  Removing debug_value: " << *dvi);
-      deleter.forceDelete(dvi);
-    }
-  }
-
-  // Remove the leftover copy_value and destroy_value instructions.
-  for (auto *inst : instsToDelete) {
-    deleter.forceDelete(inst);
-  }
-}
-
-//===----------------------------------------------------------------------===//
-//                            MARK: Top-Level API
-//===----------------------------------------------------------------------===//
-
-bool CanonicalizeOSSALifetime::computeLiveness() {
-  LLVM_DEBUG(llvm::dbgs() << "  Canonicalizing: " << currentDef);
-
-  if (currentDef->getOwnershipKind() != OwnershipKind::Owned) {
-    LLVM_DEBUG(llvm::dbgs() << "  not owned, never mind\n");
-    return false;
-  }
-
-  // Note: There is no need to register callbacks with this utility. 'onDelete'
-  // is the only one in use to handle dangling pointers, which could be done
-  // instead be registering a temporary handler with the pass. Canonicalization
-  // is only allowed to create and delete instructions that are associated with
-  // this canonical def (copies and destroys). Each canonical def has a disjoint
-  // extended lifetime. Any pass calling this utility should work at the level
-  // canonical defs, not individual instructions.
-  //
-  // NotifyWillBeDeleted will not work because copy rewriting removes operands
-  // before deleting instructions. Also prohibit setUse callbacks just because
-  // that would simply be unsound.
-  assert(!getCallbacks().notifyWillBeDeletedFunc
-         && !getCallbacks().setUseValueFunc && "unsupported");
-
-  // Step 1: compute liveness
-  if (!computeCanonicalLiveness()) {
-    LLVM_DEBUG(llvm::dbgs() << "Failed to compute canonical liveness?!\n");
-    clear();
-    return false;
-  }
-  if (respectsDeinitBarriers()) {
-    extendLexicalLivenessToDeadEnds();
-  }
-  extendLivenessToDeadEnds();
-  if (respectsDeinitBarriers()) {
-    extendLivenessToDeinitBarriers();
-  }
-  if (accessBlockAnalysis) {
-    extendLivenessThroughOverlappingAccess();
-  }
-  return true;
-}
-
-void CanonicalizeOSSALifetime::rewriteLifetimes() {
-  // Step 2: compute original boundary
-  PrunedLivenessBoundary originalBoundary;
-  findOriginalBoundary(originalBoundary);
-  PrunedLivenessBoundary extendedBoundary;
-  if (maximizeLifetime) {
-    // Step 3. (optional) maximize lifetimes
-    extendUnconsumedLiveness(originalBoundary);
-    originalBoundary.clear();
-    // Step 2: (again) recompute the original boundary since we've extended
-    //         liveness
-    findOriginalBoundary(originalBoundary);
-    // Step 4: extend boundary to destroys
-    findExtendedBoundary(originalBoundary, extendedBoundary);
-  } else {
-    // Step 3: (skipped)
-    // Step 4: extend boundary to destroys
-    findExtendedBoundary(originalBoundary, extendedBoundary);
-  }
-
-  SmallVector<DestroyValueInst *> newDestroys;
-  // Step 5: insert destroys and record consumes
-  insertDestroysOnBoundary(extendedBoundary, newDestroys);
-  // Step 6: rewrite copies and delete extra destroys
-  rewriteCopies(newDestroys);
-
-  clear();
-}
-
-/// Canonicalize a single extended owned lifetime.
-bool CanonicalizeOSSALifetime::canonicalizeValueLifetime(
-    SILValue def, ArrayRef<SILInstruction *> lexicalLifetimeEnds) {
-  LivenessState livenessState(*this, def, lexicalLifetimeEnds);
-
-  // Don't canonicalize the lifetimes of values of move-only type.  According to
-  // language rules, they are fixed.
-  if (def->getType().isMoveOnly()) {
-    return false;
-  }
-
-  // Step 1: Compute liveness.
-  if (!computeLiveness()) {
-    LLVM_DEBUG(llvm::dbgs() << "Failed to compute liveness boundary!\n");
-    return false;
-  }
-
-  // Steps 2-6. \see rewriteUses for explanation of steps 2-6.
-  rewriteLifetimes();
-
-  return true;
-}
-
-namespace swift::test {
-// Arguments:
-// - bool: pruneDebug
-// - bool: maximizeLifetimes
-// - bool: "respectAccessScopes", whether to contract lifetimes to end within
-//         access scopes which they previously enclosed but can't be hoisted
-//         before
-// - SILValue: value to canonicalize
-// - [SILInstruction]: the lexicalLifetimeEnds to recognize
-// Dumps:
-// - function after value canonicalization
-static FunctionTest CanonicalizeOSSALifetimeTest(
-    "canonicalize_ossa_lifetime",
-    [](auto &function, auto &arguments, auto &test) {
-      auto *accessBlockAnalysis =
-          test.template getAnalysis<NonLocalAccessBlockAnalysis>();
-      auto *deadEndBlocksAnalysis =
-          test.template getAnalysis<DeadEndBlocksAnalysis>();
-      auto *dominanceAnalysis = test.template getAnalysis<DominanceAnalysis>();
-      DominanceInfo *domTree = dominanceAnalysis->get(&function);
-      auto *calleeAnalysis = test.template getAnalysis<BasicCalleeAnalysis>();
-      auto pruneDebug = PruneDebugInsts_t(arguments.takeBool());
-      auto maximizeLifetimes = MaximizeLifetime_t(arguments.takeBool());
-      auto respectAccessScopes = arguments.takeBool();
-      InstructionDeleter deleter;
-      CanonicalizeOSSALifetime canonicalizer(
-          pruneDebug, maximizeLifetimes, &function,
-          respectAccessScopes ? accessBlockAnalysis : nullptr,
-          deadEndBlocksAnalysis, domTree, calleeAnalysis, deleter);
-      auto value = arguments.takeValue();
-      SmallVector<SILInstruction *, 4> lexicalLifetimeEnds;
-      while (arguments.hasUntaken()) {
-        lexicalLifetimeEnds.push_back(arguments.takeInstruction());
-      }
-      canonicalizer.canonicalizeValueLifetime(value, lexicalLifetimeEnds);
-      function.print(llvm::outs());
-    });
-} // end namespace swift::test
-
-//===----------------------------------------------------------------------===//
-//                              MARK: Debugging
-//===----------------------------------------------------------------------===//
-
-SWIFT_ASSERT_ONLY_DECL(
-  void CanonicalOSSAConsumeInfo::dump() const {
-    llvm::dbgs() << "Consumes:";
-    for (auto &blockAndInst : finalBlockConsumes) {
-      llvm::dbgs() << "  " << *blockAndInst.getSecond();
-    }
-  })
diff --git a/lib/SILOptimizer/Utils/CastOptimizer.cpp b/lib/SILOptimizer/Utils/CastOptimizer.cpp
index 048fad21e0e8d..263d6952c2a13 100644
--- a/lib/SILOptimizer/Utils/CastOptimizer.cpp
+++ b/lib/SILOptimizer/Utils/CastOptimizer.cpp
@@ -76,8 +76,7 @@ static SubstitutionMap lookupBridgeToObjCProtocolSubs(CanType target) {
   auto bridgedProto =
       target->getASTContext().getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
   auto conf = lookupConformance(target, bridgedProto);
-  return SubstitutionMap::getProtocolSubstitutions(conf.getProtocol(),
-                                                   target, conf);
+  return SubstitutionMap::getProtocolSubstitutions(conf);
 }
 
 /// Given that our insertion point is at the cast that we are trying to
@@ -109,7 +108,7 @@ convertObjectToLoadableBridgeableType(SILBuilderWithScope &builder,
     // ty. We return the cast as our value and as our new cast instruction.
     auto *cast =
         builder.createUnconditionalCheckedCast(
-          loc, dynamicCast.getIsolatedConformances(), load, silBridgedTy,
+          loc, dynamicCast.getCheckedCastOptions(), load, silBridgedTy,
           dynamicCast.getBridgedTargetType());
     return {cast, cast};
   }
@@ -145,7 +144,7 @@ convertObjectToLoadableBridgeableType(SILBuilderWithScope &builder,
   // Ok, we need to perform the full cast optimization. This means that we are
   // going to replace the cast terminator in inst_block with a checked_cast_br.
   auto *ccbi = builder.createCheckedCastBranch(loc, false,
-                                               dynamicCast.getIsolatedConformances(),
+                                               dynamicCast.getCheckedCastOptions(),
                                                load,
                                                dynamicCast.getBridgedSourceType(),
                                                silBridgedTy,
@@ -568,7 +567,7 @@ static SILValue computeFinalCastedValue(SILBuilderWithScope &builder,
     // fails since we will trap.
     if (!isConditional) {
       return builder.createUnconditionalCheckedCast(
-          loc, dynamicCast.getIsolatedConformances(), newAI,
+          loc, dynamicCast.getCheckedCastOptions(), newAI,
           destLoweredTy, destFormalTy);
     }
 
@@ -593,7 +592,7 @@ static SILValue computeFinalCastedValue(SILBuilderWithScope &builder,
         newAI->getFunction()->createBasicBlockAfter(newAI->getParent());
     condBrSuccessBB->createPhiArgument(destLoweredTy, OwnershipKind::Owned);
     builder.createCheckedCastBranch(loc, /* isExact*/ false,
-                                    dynamicCast.getIsolatedConformances(),
+                                    dynamicCast.getCheckedCastOptions(),
                                     newAI,
                                     sourceFormalTy, destLoweredTy, destFormalTy,
                                     condBrSuccessBB, failureBB);
@@ -1065,8 +1064,7 @@ CastOptimizer::simplifyCheckedCastBranchInst(CheckedCastBranchInst *Inst) {
       // The unconditional_cast can be skipped, if the result of a cast
       // is not used afterwards.
       if (!ResultNotUsed) {
-        if (!dynamicCast.canSILUseScalarCheckedCastInstructions())
-          return nullptr;
+        ASSERT(dynamicCast.canSILUseScalarCheckedCastInstructions());
 
         CastedValue =
             emitSuccessfulScalarUnconditionalCast(Builder, Loc, dynamicCast);
@@ -1076,7 +1074,7 @@ CastOptimizer::simplifyCheckedCastBranchInst(CheckedCastBranchInst *Inst) {
       if (!CastedValue)
         CastedValue =
             Builder.createUnconditionalCheckedCast(
-              Loc, Inst->getIsolatedConformances(), Op, TargetLoweredType,
+              Loc, Inst->getCheckedCastOptions(), Op, TargetLoweredType,
               TargetFormalType);
     }
 
@@ -1161,13 +1159,13 @@ SILInstruction *CastOptimizer::optimizeCheckedCastAddrBranchInst(
 
       if (MI) {
         if (SuccessBB->getSinglePredecessorBlock() &&
-            canSILUseScalarCheckedCastInstructions(
-                Inst->getModule(), MI->getType().getASTType(),
-                Inst->getTargetFormalType())) {
+            canOptimizeToScalarCheckedCastInstructions(
+                Inst->getFunction(), MI->getType().getASTType(),
+                Inst->getTargetFormalType(), Inst->getConsumptionKind())) {
           SILBuilderWithScope B(Inst, builderContext);
           auto NewI = B.createCheckedCastBranch(
               Loc, false /*isExact*/,
-              Inst->getIsolatedConformances(),
+              Inst->getCheckedCastOptions(),
               MI,
               Inst->getSourceFormalType(),
               Inst->getTargetLoweredType().getObjectType(),
@@ -1212,7 +1210,7 @@ CastOptimizer::optimizeCheckedCastBranchInst(CheckedCastBranchInst *Inst) {
     }
     return B.createCheckedCastBranch(
         dynamicCast.getLocation(), false /*isExact*/,
-        dynamicCast.getIsolatedConformances(),
+        dynamicCast.getCheckedCastOptions(),
         mi,
         // The cast is now from the MetatypeInst, so get the source formal
         // type from it.
@@ -1482,6 +1480,9 @@ static bool optimizeStaticallyKnownProtocolConformance(
     if (Conformance.isInvalid())
       return false;
 
+    if (!matchesActorIsolation(Conformance, Inst->getFunction()))
+      return false;
+
     auto layout = TargetType->getExistentialLayout();
     if (layout.getProtocols().size() != 1)
       return false;
diff --git a/lib/SILOptimizer/Utils/ConstExpr.cpp b/lib/SILOptimizer/Utils/ConstExpr.cpp
index 569152abb50bf..fc2b698740e8e 100644
--- a/lib/SILOptimizer/Utils/ConstExpr.cpp
+++ b/lib/SILOptimizer/Utils/ConstExpr.cpp
@@ -1785,8 +1785,8 @@ ConstExprFunctionState::evaluateInstructionAndGetNext(
     // Set up basic block arguments.
     for (unsigned i = 0, e = br->getNumArgs(); i != e; ++i) {
       auto argument = getConstantValue(br->getArg(i));
-      if (!argument.isConstant())
-        return {std::nullopt, argument};
+      // Do not fail if an argument is not constant because we still know enough to know what the next instruction will be.
+      // Failure may occur later, however, if/when this unknown argument value is used by an instruction in the target basic block.
       setValue(destBB->getArgument(i), argument);
     }
     // Set the instruction pointer to the first instruction of the block.
@@ -1874,7 +1874,7 @@ ConstExprFunctionState::evaluateInstructionAndGetNext(
     CanType targetType = substituteGenericParamsAndSimplify(
         checkedCastInst->getTargetFormalType());
     DynamicCastFeasibility castResult = classifyDynamicCast(
-        inst->getModule().getSwiftModule(), sourceType, targetType);
+        inst->getFunction(), sourceType, targetType);
     if (castResult == DynamicCastFeasibility::MaySucceed) {
       return {std::nullopt, getUnknown(evaluator, inst->asSILNode(),
                                        UnknownReason::UnknownCastResult)};
diff --git a/lib/SILOptimizer/Utils/Devirtualize.cpp b/lib/SILOptimizer/Utils/Devirtualize.cpp
index c4aec4cb77e48..1a90cd539d48b 100644
--- a/lib/SILOptimizer/Utils/Devirtualize.cpp
+++ b/lib/SILOptimizer/Utils/Devirtualize.cpp
@@ -405,8 +405,6 @@ combineSubstitutionMaps(SubstitutionMap firstSubMap,
                         unsigned firstDepth,
                         unsigned secondDepth,
                         GenericSignature genericSig) {
-  auto &ctx = genericSig->getASTContext();
-
   return SubstitutionMap::get(
     genericSig,
     [&](SubstitutableType *type) {
@@ -414,12 +412,8 @@ combineSubstitutionMaps(SubstitutionMap firstSubMap,
       if (gp->getDepth() < firstDepth)
         return QuerySubstitutionMap{firstSubMap}(gp);
 
-      auto *replacement = GenericTypeParamType::get(
-          gp->getParamKind(),
-          gp->getDepth() + secondDepth - firstDepth,
-          gp->getIndex(),
-          gp->getValueType(),
-          ctx);
+      auto *replacement = gp->withDepth(
+          gp->getDepth() + secondDepth - firstDepth);
       return QuerySubstitutionMap{secondSubMap}(replacement);
     },
     // We might not have enough information in the substitution maps alone.
@@ -718,7 +712,7 @@ void swift::deleteDevirtualizedApply(ApplySite old) {
   recursivelyDeleteTriviallyDeadInstructions(oldApply, true);
 }
 
-SILFunction *swift::getTargetClassMethod(SILModule &module, ClassDecl *cd,
+SILFunction *swift::getTargetClassMethod(SILModule &module, FullApplySite as, ClassDecl *cd,
                                          CanType classType, MethodInst *mi) {
   assert((isa<ClassMethodInst>(mi) || isa<SuperMethodInst>(mi)) &&
          "Only class_method and super_method instructions are supported");
@@ -727,6 +721,11 @@ SILFunction *swift::getTargetClassMethod(SILModule &module, ClassDecl *cd,
 
   SILType silType = SILType::getPrimitiveObjectType(classType);
   if (auto *vtable = module.lookUpSpecializedVTable(silType)) {
+    // We cannot de-virtualize a generic method call to a specialized method.
+    // This would result in wrong argument/return calling conventions.
+    if (as.getSubstitutionMap().hasAnySubstitutableParams())
+      return nullptr;
+
     return vtable->getEntry(module, member)->getImplementation();
   }
 
@@ -763,7 +762,7 @@ bool swift::canDevirtualizeClassMethod(FullApplySite applySite, ClassDecl *cd,
   auto *mi = cast<MethodInst>(applySite.getCallee());
 
   // Find the implementation of the member which should be invoked.
-  auto *f = getTargetClassMethod(module, cd, classType, mi);
+  auto *f = getTargetClassMethod(module, applySite, cd, classType, mi);
 
   // If we do not find any such function, we have no function to devirtualize
   // to... so bail.
@@ -849,7 +848,7 @@ swift::devirtualizeClassMethod(SILPassManager *pm, FullApplySite applySite,
   SILModule &module = applySite.getModule();
   auto *mi = cast<MethodInst>(applySite.getCallee());
 
-  auto *f = getTargetClassMethod(module, cd, classType, mi);
+  auto *f = getTargetClassMethod(module, applySite, cd, classType, mi);
 
   CanSILFunctionType genCalleeType = f->getLoweredFunctionTypeInContext(
       TypeExpansionContext(*applySite.getFunction()));
@@ -1056,19 +1055,16 @@ getWitnessMethodSubstitutions(
         }
 
         if (depth < baseDepth) {
-          paramType = GenericTypeParamType::get(paramType->getParamKind(),
-              depth, paramType->getIndex(), paramType->getValueType(), ctx);
-
+          paramType = paramType->withDepth(depth);
           return Type(paramType).subst(baseSubMap);
         }
 
         depth = depth - baseDepth + 1;
 
-        paramType = GenericTypeParamType::get(paramType->getParamKind(),
-            depth, paramType->getIndex(), paramType->getValueType(), ctx);
+        paramType = paramType->withDepth(depth);
         return Type(paramType).subst(origSubMap);
       },
-      [&](CanType type, Type substType, ProtocolDecl *proto) {
+      [&](InFlightSubstitution &IFS, Type type, ProtocolDecl *proto) {
         auto *paramType = type->getRootGenericParam();
         unsigned depth = paramType->getDepth();
 
@@ -1084,31 +1080,27 @@ getWitnessMethodSubstitutions(
 
         if (depth < baseDepth) {
           type = CanType(type.transformRec([&](TypeBase *t) -> std::optional<Type> {
-            if (t == paramType) {
-              return Type(GenericTypeParamType::get(paramType->getParamKind(),
-                  depth, paramType->getIndex(), paramType->getValueType(), ctx));
-            }
+            if (t == paramType)
+              return paramType->withDepth(depth);
 
             assert(!isa<GenericTypeParamType>(t));
             return std::nullopt;
           }));
 
-          return baseSubMap.lookupConformance(type, proto);
+          return baseSubMap.lookupConformance(type->getCanonicalType(), proto);
         }
 
         depth = depth - baseDepth + 1;
 
         type = CanType(type.transformRec([&](TypeBase *t) -> std::optional<Type> {
-          if (t == paramType) {
-            return Type(GenericTypeParamType::get(paramType->getParamKind(),
-                depth, paramType->getIndex(), paramType->getValueType(), ctx));
-          }
+          if (t == paramType)
+            return paramType->withDepth(depth);
 
           assert(!isa<GenericTypeParamType>(t));
           return std::nullopt;
         }));
 
-        return origSubMap.lookupConformance(type, proto);
+        return origSubMap.lookupConformance(type->getCanonicalType(), proto);
       });
 }
 
diff --git a/lib/SILOptimizer/Utils/Existential.cpp b/lib/SILOptimizer/Utils/Existential.cpp
index 3a11eddb450db..b3d18b6ffcfbe 100644
--- a/lib/SILOptimizer/Utils/Existential.cpp
+++ b/lib/SILOptimizer/Utils/Existential.cpp
@@ -262,8 +262,8 @@ void ConcreteExistentialInfo::initializeSubstitutionMap(
 
   ExistentialSubs = SubstitutionMap::get(
       ExistentialSig, [&](SubstitutableType *type) { return ConcreteType; },
-      [&](CanType /*depType*/, Type /*replaceType*/,
-          ProtocolDecl *proto) -> ProtocolConformanceRef {
+      [&](InFlightSubstitution &, Type, ProtocolDecl *proto)
+          -> ProtocolConformanceRef {
         // Directly providing ExistentialConformances to the SubstitutionMap will
         // fail because of the mismatch between opened archetype conformance and
         // existential value conformance. Instead, provide a conformance lookup
diff --git a/lib/SILOptimizer/Utils/Generics.cpp b/lib/SILOptimizer/Utils/Generics.cpp
index 2e6c0512a7b34..9fbf130a2969d 100644
--- a/lib/SILOptimizer/Utils/Generics.cpp
+++ b/lib/SILOptimizer/Utils/Generics.cpp
@@ -455,6 +455,82 @@ static bool shouldNotSpecialize(SILFunction *Callee, SILFunction *Caller,
   return false;
 }
 
+// Addressable parameters cannot be dropped because the address may
+// escape. They also can't be promoted to direct convention, so there
+// is no danger in preserving them.
+static bool canConvertArg(CanSILFunctionType substType, unsigned paramIdx,
+                          SILFunction *caller) {
+  return !substType->isAddressable(paramIdx, caller);
+}
+
+// If there is no read from an indirect argument, this argument has to be
+// dropped. At the call site the store to the argument's memory location could
+// have been removed (based on the callee's memory effects).  Therefore,
+// converting such an unused indirect argument to a direct argument, would load
+// an uninitialized value at the call site.  This would lead to verifier errors
+// and in worst case to a miscompile because IRGen can implicitly use dead
+// arguments, e.g. for getting the type of a class reference.
+static bool canDropUnusedArg(ApplySite apply, SILFunction *callee,
+                             CanSILFunctionType substType,
+                             unsigned paramIdx) {
+  FullApplySite fas = apply.asFullApplySite();
+  if (!fas) {
+    return false;
+  }
+  Operand &op = fas.getOperandsWithoutIndirectResults()[paramIdx];
+  return !callee->argumentMayRead(&op, op.get());
+}
+
+static bool isUsedAsDynamicSelf(SILArgument *arg) {
+  for (Operand *use : arg->getUses()) {
+    if (use->isTypeDependent())
+      return true;
+  }
+  return false;
+}
+
+static bool canDropMetatypeArg(ApplySite apply, SILFunction *callee,
+                               unsigned paramIdx) {
+  if (!callee->isDefinition())
+    return false;
+
+  unsigned calleeArgIdx =
+    apply.getSubstCalleeConv().getSILArgIndexOfFirstParam() + paramIdx;
+  SILArgument *calleeArg = callee->getArguments()[calleeArgIdx];
+
+  if (isUsedAsDynamicSelf(calleeArg))
+    return false;
+
+  if (calleeArg->getType().getASTType()->hasDynamicSelfType())
+    return false;
+
+  // We don't drop metatype arguments of not applied arguments (in case of
+  // `partial_apply`).
+  unsigned firstAppliedArgIdx = apply.getCalleeArgIndexOfFirstAppliedArg();
+  if (firstAppliedArgIdx > calleeArgIdx)
+      return false;
+
+  auto mt = calleeArg->getType().castTo<MetatypeType>();
+  if (mt->hasRepresentation()
+      && mt->getRepresentation() == MetatypeRepresentation::Thin) {
+    return true;
+  }
+  // If the passed thick metatype value is not a `metatype` instruction
+  // we don't know the real metatype at runtime. It's not necessarily the
+  // same as the declared metatype. It could e.g. be an upcast of a class
+  // metatype.
+  SILValue callerArg = apply.getArguments()[calleeArgIdx - firstAppliedArgIdx];
+  if (isa<MetatypeInst>(callerArg))
+    return true;
+
+  // But: if the metatype is not used in the callee we don't have to care
+  // what metatype value is passed. We can just remove it.
+  if (onlyHaveDebugUses(calleeArg))
+    return true;
+
+  return false;
+}
+
 /// Prepares the ReabstractionInfo object for further processing and checks
 /// if the current function can be specialized at all.
 /// Returns false, if the current function cannot be specialized.
@@ -525,7 +601,7 @@ bool ReabstractionInfo::prepareAndCheck(ApplySite Apply, SILFunction *Callee,
 
     // Check only the substitutions for the generic parameters.
     // Ignore any dependent types, etc.
-    auto Replacement = Type(GP).subst(CalleeParamSubMap);
+    auto Replacement = Type(GP).subst(CalleeParamSubMap)->getCanonicalType();
     if (!Replacement->is<ArchetypeType>())
       HasNonArchetypeGenericParams = true;
 
@@ -771,7 +847,7 @@ void ReabstractionInfo::createSubstitutedAndSpecializedTypes() {
   for (SILParameterInfo PI : SubstitutedType->getParameters()) {
     auto IdxToInsert = IdxForParam;
     ++IdxForParam;
-    unsigned argIdx = i++;
+    unsigned paramIdx = i++;
 
     SILFunctionConventions substConv(SubstitutedType, getModule());
     TypeCategory tc = getParamTypeCategory(PI, substConv, getResilienceExpansion());
@@ -782,22 +858,14 @@ void ReabstractionInfo::createSubstitutedAndSpecializedTypes() {
     case ParameterConvention::Indirect_In_CXX:
     case ParameterConvention::Indirect_In:
     case ParameterConvention::Indirect_In_Guaranteed: {
-      if (Callee && Apply && dropUnusedArguments) {
-        // If there is no read from an indirect argument, this argument has to
-        // be dropped. At the call site the store to the argument's memory location
-        // could have been removed (based on the callee's memory effects).
-        // Therefore, converting such an unused indirect argument to a direct
-        // argument, would load an uninitialized value at the call site.
-        // This would lead to verifier errors and in worst case to a miscompile
-        // because IRGen can implicitly use dead arguments, e.g. for getting the
-        // type of a class reference.
-        if (FullApplySite fas = Apply.asFullApplySite()) {
-          Operand &op = fas.getOperandsWithoutIndirectResults()[argIdx];
-          if (!Callee->argumentMayRead(&op, op.get())) {
-            droppedArguments.set(IdxToInsert);
-            break;
-          }
-        }
+      if (Apply && !canConvertArg(SubstitutedType, paramIdx,
+                                  Apply.getFunction())) {
+        continue;
+      }
+      if (Callee && Apply && dropUnusedArguments
+          && canDropUnusedArg(Apply, Callee, SubstitutedType, paramIdx)) {
+        droppedArguments.set(IdxToInsert);
+        break;
       }
       Conversions.set(IdxToInsert);
       if (tc == LoadableAndTrivial)
@@ -822,8 +890,10 @@ void ReabstractionInfo::createSubstitutedAndSpecializedTypes() {
     case ParameterConvention::Direct_Unowned:
     case ParameterConvention::Direct_Guaranteed: {
       CanType ty = PI.getInterfaceType();
-      if (dropUnusedArguments && isa<MetatypeType>(ty) && !ty->hasArchetype())
+      if (dropUnusedArguments && isa<MetatypeType>(ty) && !ty->hasArchetype()
+          && Apply && Callee && canDropMetatypeArg(Apply, Callee, paramIdx)) {
         droppedArguments.set(IdxToInsert);
+      }
       break;
     }
     }
@@ -2916,7 +2986,8 @@ static bool createPrespecialized(StringRef UnspecializedName,
   ReabstractionInfo ReInfo(M.getSwiftModule(), M.isWholeModule(), ApplySite(),
                            UnspecFunc, Apply.getSubstitutionMap(),
                            IsNotSerialized,
-                           /*ConvertIndirectToDirect= */true, /*dropMetatypeArgs=*/ false);
+                           /*ConvertIndirectToDirect= */true,
+                           /*dropUnusedArguments=*/ false);
 
   if (!ReInfo.canBeSpecialized())
     return false;
@@ -3005,7 +3076,7 @@ static bool usePrespecialized(
                                       funcBuilder.getModule().isWholeModule(), apply, refF,
                                       apply.getSubstitutionMap(), IsNotSerialized,
                                       /*ConvertIndirectToDirect=*/ true,
-                                      /*dropMetatypeArgs=*/ false);
+                                      /*dropUnusedArguments=*/ false);
 
   for (auto *SA : refF->getSpecializeAttrs()) {
     if (!SA->isExported())
@@ -3058,7 +3129,7 @@ static bool usePrespecialized(
           SA->getUnerasedSpecializedSignature().withoutMarkerProtocols();
 
       auto erasedParams = SA->getTypeErasedParams();
-      if(!ctxt.LangOpts.hasFeature(Feature::LayoutPrespecialization) || erasedParams.empty()) {
+      if (erasedParams.empty()) {
         continue;
       }
 
@@ -3149,7 +3220,8 @@ static bool usePrespecialized(
           funcBuilder.getModule().getSwiftModule(),
           funcBuilder.getModule().isWholeModule(), apply, refF, newSubstMap,
           apply.getFunction()->getSerializedKind(),
-          /*ConvertIndirectToDirect=*/ true, /*dropMetatypeArgs=*/ false, nullptr);
+          /*ConvertIndirectToDirect=*/ true,
+          /*dropUnusedArguments=*/ false, nullptr);
 
       if (layoutReInfo.getSpecializedType() == reInfo.getSpecializedType()) {
         layoutMatches.push_back(
@@ -3209,57 +3281,6 @@ static bool usePrespecialized(
   return false;
 }
 
-static bool isUsedAsDynamicSelf(SILArgument *arg) {
-  for (Operand *use : arg->getUses()) {
-    if (use->isTypeDependent())
-      return true;
-  }
-  return false;
-}
-
-static bool canDropMetatypeArgs(ApplySite apply, SILFunction *callee) {
-  if (!callee->isDefinition())
-    return false;
-
-  auto calleeArgs = callee->getArguments();
-  unsigned firstAppliedArgIdx = apply.getCalleeArgIndexOfFirstAppliedArg();
-  for (unsigned calleeArgIdx = 0; calleeArgIdx < calleeArgs.size(); ++calleeArgIdx) {
-    SILArgument *calleeArg = calleeArgs[calleeArgIdx];
-    auto mt = calleeArg->getType().getAs<MetatypeType>();
-    if (!mt)
-      continue;
-
-    if (isUsedAsDynamicSelf(calleeArg))
-      return false;
-
-    if (calleeArg->getType().getASTType()->hasDynamicSelfType())
-      return false;
-
-    // We don't drop metatype arguments of not applied arguments (in case of `partial_apply`).
-    if (firstAppliedArgIdx > calleeArgIdx)
-      return false;
-
-    if (mt->hasRepresentation() && mt->getRepresentation() == MetatypeRepresentation::Thin)
-      continue;
-
-    // If the passed thick metatype value is not a `metatype` instruction
-    // we don't know the real metatype at runtime. It's not necessarily the
-    // same as the declared metatype. It could e.g. be an upcast of a class
-    // metatype.
-    SILValue callerArg = apply.getArguments()[calleeArgIdx - firstAppliedArgIdx];
-    if (isa<MetatypeInst>(callerArg))
-      continue;
-
-    // But: if the metatype is not used in the callee we don't have to care
-    // what metatype value is passed. We can just remove it.
-    if (callee->isDefinition() && onlyHaveDebugUses(calleeArg))
-      continue;
-
-    return false;
-  }
-  return true;
-}
-
 void swift::trySpecializeApplyOfGeneric(
     SILOptFunctionBuilder &FuncBuilder,
     ApplySite Apply, DeadInstructionSet &DeadApplies,
@@ -3312,7 +3333,7 @@ void swift::trySpecializeApplyOfGeneric(
                            FuncBuilder.getModule().isWholeModule(), Apply, RefF,
                            Apply.getSubstitutionMap(), serializedKind,
                            /*ConvertIndirectToDirect=*/ true,
-                           /*dropMetatypeArgs=*/ canDropMetatypeArgs(Apply, RefF),
+                           /*dropUnusedArguments=*/ true,
                            &ORE);
   if (!ReInfo.canBeSpecialized())
     return;
diff --git a/lib/SILOptimizer/Utils/InstOptUtils.cpp b/lib/SILOptimizer/Utils/InstOptUtils.cpp
index e3bf12e079d63..3a80401d16374 100644
--- a/lib/SILOptimizer/Utils/InstOptUtils.cpp
+++ b/lib/SILOptimizer/Utils/InstOptUtils.cpp
@@ -179,6 +179,14 @@ bool swift::isInstructionTriviallyDead(SILInstruction *inst) {
   if (isa<BorrowedFromInst>(inst))
     return false;
 
+  // A dead `destructure_struct` with an owned argument can appear for a non-copyable or
+  // non-escapable struct which has only trivial elements. The instruction is not trivially
+  // dead because it ends the lifetime of its operand.
+  if (isa<DestructureStructInst>(inst) &&
+      inst->getOperand(0)->getOwnershipKind() == OwnershipKind::Owned) {
+    return false;
+  }
+
   // These invalidate enums so "write" memory, but that is not an essential
   // operation so we can remove these if they are trivially dead.
   if (isa<UncheckedTakeEnumDataAddrInst>(inst))
@@ -774,7 +782,8 @@ swift::castValueToABICompatibleType(SILBuilder *builder, SILPassManager *pm,
 }
 
 namespace {
-  class TypeDependentVisitor : public CanTypeVisitor<TypeDependentVisitor, bool> {
+  class TypeDependentVisitor :
+      public CanTypeVisitor_AnyNominal<TypeDependentVisitor, bool> {
   public:
     // If the type isn't actually dependent, we're okay.
     bool visit(CanType type) {
@@ -783,11 +792,8 @@ namespace {
       return CanTypeVisitor::visit(type);
     }
 
-    bool visitStructType(CanStructType type) {
-      return visitStructDecl(type->getDecl());
-    }
-    bool visitBoundGenericStructType(CanBoundGenericStructType type) {
-      return visitStructDecl(type->getDecl());
+    bool visitAnyStructType(CanType type, StructDecl *decl) {
+      return visitStructDecl(decl);
     }
     bool visitStructDecl(StructDecl *decl) {
       auto rawLayout = decl->getAttrs().getAttribute<RawLayoutAttr>();
@@ -806,11 +812,8 @@ namespace {
       return false;
     }
 
-    bool visitEnumType(CanEnumType type) {
-      return visitEnumDecl(type->getDecl());
-    }
-    bool visitBoundGenericEnumType(CanBoundGenericEnumType type) {
-      return visitEnumDecl(type->getDecl());
+    bool visitAnyEnumType(CanType type, EnumDecl *decl) {
+      return visitEnumDecl(decl);
     }
     bool visitEnumDecl(EnumDecl *decl) {
       if (decl->isIndirect())
@@ -835,12 +838,9 @@ namespace {
     }
 
     // A class reference does not depend on the layout of the class.
-    bool visitClassType(CanClassType type) {
+    bool visitAnyClassType(CanType type, ClassDecl *decl) {
       return false;
      }
-    bool visitBoundGenericClassType(CanBoundGenericClassType type) {
-      return false;
-    }
 
     // The same for non-strong references.
     bool visitReferenceStorageType(CanReferenceStorageType type) {
@@ -963,6 +963,9 @@ static bool useHasTransitiveOwnership(const SILInstruction *inst) {
   if (isa<ConvertEscapeToNoEscapeInst>(inst))
     return true;
 
+  if (isa<MarkDependenceInst>(inst))
+    return true;
+
   // Look through copy_value, begin_borrow, move_value. They are inert for our
   // purposes, but we need to look through it.
   return isa<CopyValueInst>(inst) || isa<BeginBorrowInst>(inst) ||
@@ -1026,7 +1029,7 @@ void swift::emitDestroyOperation(SILBuilder &builder, SILLocation loc,
       return;
     }
 
-    callbacks.createdNewInst(u.get<StrongReleaseInst *>());
+    callbacks.createdNewInst(cast<StrongReleaseInst *>(u));
     return;
   }
 
@@ -1039,7 +1042,7 @@ void swift::emitDestroyOperation(SILBuilder &builder, SILLocation loc,
     return;
   }
 
-  callbacks.createdNewInst(u.get<ReleaseValueInst *>());
+  callbacks.createdNewInst(cast<ReleaseValueInst *>(u));
 }
 
 // NOTE: The ownership of the partial_apply argument does not match the
@@ -1095,13 +1098,16 @@ void swift::getConsumedPartialApplyArgs(PartialApplyInst *pai,
   }
 }
 
-bool swift::collectDestroys(SingleValueInstruction *inst,
-                            SmallVectorImpl<Operand *> &destroys) {
+static bool collectDestroysRecursively(SingleValueInstruction *inst,
+                                       SmallVectorImpl<Operand *> &destroys,
+                                       InstructionSet &visited) {
   bool isDead = true;
   for (Operand *use : inst->getUses()) {
     SILInstruction *user = use->getUser();
+    if (!visited.insert(user))
+      continue;
     if (useHasTransitiveOwnership(user)) {
-      if (!collectDestroys(cast<SingleValueInstruction>(user), destroys))
+      if (!collectDestroysRecursively(cast<SingleValueInstruction>(user), destroys, visited))
         isDead = false;
       destroys.push_back(use);
     } else if (useDoesNotKeepValueAlive(user)) {
@@ -1113,6 +1119,12 @@ bool swift::collectDestroys(SingleValueInstruction *inst,
   return isDead;
 }
 
+bool swift::collectDestroys(SingleValueInstruction *inst,
+                            SmallVectorImpl<Operand *> &destroys) {
+  InstructionSet visited(inst->getFunction());
+  return collectDestroysRecursively(inst, destroys, visited);
+}
+
 /// Move the original arguments of the partial_apply into newly created
 /// temporaries to extend the lifetime of the arguments until the partial_apply
 /// is finally destroyed.
diff --git a/lib/SILOptimizer/Utils/InstructionDeleter.cpp b/lib/SILOptimizer/Utils/InstructionDeleter.cpp
index 6e9e178a58101..ffefbc874ac46 100644
--- a/lib/SILOptimizer/Utils/InstructionDeleter.cpp
+++ b/lib/SILOptimizer/Utils/InstructionDeleter.cpp
@@ -63,6 +63,12 @@ static bool isScopeAffectingInstructionDead(SILInstruction *inst,
     return false;
   }
 
+  // Don't delete dead drop_deinit instruction. They are a marker to eliminate
+  // user-defined deinit and we do not want to lose it.
+  if (isa<DropDeinitInst>(inst)) {
+    return false;
+  }
+
   for (auto result : inst->getResults()) {
     // If inst has any owned move-only value as a result, deleting it may
     // shorten that value's lifetime which is illegal according to language
@@ -181,9 +187,8 @@ bool InstructionDeleter::trackIfDead(SILInstruction *inst) {
   bool fixLifetime = inst->getFunction()->hasOwnership();
   if (isInstructionTriviallyDead(inst)
       || isScopeAffectingInstructionDead(inst, fixLifetime)) {
-    assert(!isIncidentalUse(inst) &&
-           (!isa<DestroyValueInst>(inst) ||
-            canTriviallyDeleteOSSAEndScopeInst(inst)) &&
+    assert(!isIncidentalUse(inst)
+           || canTriviallyDeleteOSSAEndScopeInst(inst) &&
            "Incidental uses cannot be removed in isolation. "
            "They would be removed iff the operand is dead");
     getCallbacks().notifyWillBeDeleted(inst);
@@ -268,9 +273,16 @@ void InstructionDeleter::deleteWithUses(SILInstruction *inst, bool fixLifetimes,
       if (fixLifetimes) {
         LoadInst *li = nullptr;
         if (operand.isConsuming()) {
-          SILBuilderWithScope builder(inst);
-          auto *dvi = builder.createDestroyValue(inst->getLoc(), operandValue);
-          getCallbacks().createdNewInst(dvi);
+          if (isa<DropDeinitInst>(operandValue)) {
+            SILBuilderWithScope builder(inst);
+            auto *eli = builder.createEndLifetime(inst->getLoc(), operandValue);
+            getCallbacks().createdNewInst(eli);
+          } else {
+            SILBuilderWithScope builder(inst);
+            auto *dvi =
+                builder.createDestroyValue(inst->getLoc(), operandValue);
+            getCallbacks().createdNewInst(dvi);
+          }
         } else if ((li = dyn_cast<LoadInst>(inst)) &&
                    li->getOwnershipQualifier() ==
                        LoadOwnershipQualifier::Take) {
@@ -343,6 +355,20 @@ static FunctionTest DeleterDeleteIfDeadTest(
       llvm::outs() << "deleteIfDead returned " << deleted << "\n";
       function.print(llvm::outs());
     });
+
+// Arguments:
+// - instruction: the instruction to delete
+// Dumps:
+// - the function
+static FunctionTest DeleterTrackIfDeadTest(
+    "deleter_track_if_dead", [](auto &function, auto &arguments, auto &test) {
+      auto *inst = arguments.takeInstruction();
+      InstructionDeleter deleter;
+      llvm::outs() << "Tracking " << *inst;
+      deleter.trackIfDead(inst);
+      deleter.cleanupDeadInstructions();
+      function.print(llvm::outs());
+    });
 } // namespace swift::test
 
 void InstructionDeleter::forceDeleteAndFixLifetimes(SILInstruction *inst) {
diff --git a/lib/SILOptimizer/Utils/KeyPathProjector.cpp b/lib/SILOptimizer/Utils/KeyPathProjector.cpp
index b7da792aaf374..78458fec0d452 100644
--- a/lib/SILOptimizer/Utils/KeyPathProjector.cpp
+++ b/lib/SILOptimizer/Utils/KeyPathProjector.cpp
@@ -674,8 +674,8 @@ class CompleteKeyPathProjector : public KeyPathProjector {
 
 KeyPathInst *
 KeyPathProjector::getLiteralKeyPath(SILValue keyPath) {
-  while (auto *upCast = dyn_cast<UpcastInst>(keyPath)) {
-    keyPath = lookThroughOwnershipInsts(upCast->getOperand());
+  while (isa<UpcastInst>(keyPath) || isa<OpenExistentialRefInst>(keyPath)) {
+    keyPath = lookThroughOwnershipInsts(cast<SingleValueInstruction>(keyPath)->getOperand(0));
   }
 
   return dyn_cast<KeyPathInst>(keyPath);
diff --git a/lib/SILOptimizer/Utils/LexicalDestroyFolding.cpp b/lib/SILOptimizer/Utils/LexicalDestroyFolding.cpp
index 91403fa8e62f6..2d7f2457ff199 100644
--- a/lib/SILOptimizer/Utils/LexicalDestroyFolding.cpp
+++ b/lib/SILOptimizer/Utils/LexicalDestroyFolding.cpp
@@ -9,7 +9,7 @@
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//
-/// After ShrinkBorrowScope and CanonicalizeOSSALifetime both run, when a final
+/// After ShrinkBorrowScope and OSSACanonicalizeOwned both run, when a final
 /// use of the extended simple lifetime of a begin_borrow [lexical] is as an
 /// owned argument, we will have the following pattern:
 ///
@@ -89,9 +89,9 @@
 #include "swift/SIL/Test.h"
 #include "swift/SILOptimizer/Analysis/Reachability.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h"
 #include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
 #include "swift/SILOptimizer/Utils/SILSSAUpdater.h"
 #include "llvm/ADT/SmallVector.h"
 
@@ -218,7 +218,7 @@ class FindCandidates final {
   ///
   ///     apply
   ///     end_borrow
-  ///     ...           // instructions which CanonicalizeOSSALifetime will not
+  ///     ...           // instructions which OSSACanonicalizeOwned will not
   ///                   // hoist destroys over
   ///     destroy_value %borrowee
   ///
@@ -235,13 +235,13 @@ class FindCandidates final {
   /// sequence of "inconsequential" instructions the last of which destroys
   /// %borrowee.
   ///
-  /// CanonicalizeOSSALifetime will put destroy_value instructions after every
+  /// OSSACanonicalizeOwned will put destroy_value instructions after every
   /// final non-consuming use of %borrowee.  So it will put a
   /// destroy_value after an
   ///     end_borrow %lifetime
   /// if there are no subsequent uses of %borrowee.  However, if there
   /// is already one or more other instructions whose opcodes satisfy
-  /// CanonicalizeOSSALifetime::ignoredByDestroyHoisting just after
+  /// OSSACanonicalizeOwned::ignoredByDestroyHoisting just after
   ///     end_borrow %lifetime,
   /// it won't hoist the
   ///     destroy_value %borrowee
@@ -692,9 +692,9 @@ FindCandidates::definesMatchingInstructionSequence(SILInstruction *inst) const {
 DestroyValueInst *
 FindCandidates::findNextBorroweeDestroy(SILInstruction *from) const {
   for (auto *inst = from; inst; inst = inst->getNextInstruction()) {
-    if (!CanonicalizeOSSALifetime::ignoredByDestroyHoisting(inst->getKind())) {
-      // This is not an instruction that CanonicalizeOSSALifetime would not
-      // hoist a destroy above.  In other words, CanonicalizeOSSALifetime would
+    if (!OSSACanonicalizeOwned::ignoredByDestroyHoisting(inst->getKind())) {
+      // This is not an instruction that OSSACanonicalizeOwned would not
+      // hoist a destroy above.  In other words, OSSACanonicalizeOwned would
       // have hoisted
       //     destroy_value %borrowee
       // over this instruction if it could have.  Stop looking.
diff --git a/lib/SILOptimizer/Utils/LoopUtils.cpp b/lib/SILOptimizer/Utils/LoopUtils.cpp
index 4447192c06f61..2e30ca393a178 100644
--- a/lib/SILOptimizer/Utils/LoopUtils.cpp
+++ b/lib/SILOptimizer/Utils/LoopUtils.cpp
@@ -218,9 +218,21 @@ bool swift::canonicalizeAllLoops(DominanceInfo *DT, SILLoopInfo *LI) {
   return MadeChange;
 }
 
-bool swift::canDuplicateLoopInstruction(SILLoop *L, SILInstruction *I) {
+bool swift::canDuplicateLoopInstruction(SILLoop *L, SILInstruction *I, DeadEndBlocks *deb) {
   SinkAddressProjections sinkProj;
   for (auto res : I->getResults()) {
+    // If a guaranteed value is used in a dead-end exit block and the enclosing value
+    // is _not_ destroyed in this block, we end up missing the enclosing value as
+    // phi-argument after duplicating the loop.
+    // TODO: once we have complete lifetimes we can remove this check
+    if (res->getOwnershipKind() == OwnershipKind::Guaranteed) {
+      for (Operand *use : res->getUses()) {
+        SILBasicBlock *useBlock = use->getUser()->getParent();
+        if (!L->contains(useBlock) && deb->isDeadEnd(useBlock))
+          return false;
+      }
+    }
+
     if (!res->getType().isAddress()) {
       continue;
     }
diff --git a/lib/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.cpp b/lib/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.cpp
new file mode 100644
index 0000000000000..5695e1091c072
--- /dev/null
+++ b/lib/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.cpp
@@ -0,0 +1,884 @@
+//===-- OSSACanonicalizeGuaranteed.cpp - Canonicalize OSSA borrow scopes --===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// TODO: Enable -canonical-ossa-rewrite-borrows by default (see
+/// CopyPropagation).
+///
+/// TODO: Add support for load_borrows, and reborrows by using persistentCopies.
+///
+/// TODO: Hoist struct/tuple with multiple operands out of borrow scopes if that
+/// ever happens. Consider modeling them as reborrows instead.
+///
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "copy-propagation"
+
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/Basic/Defer.h"
+#include "swift/SIL/InstructionUtils.h"
+#include "swift/SIL/OwnershipUtils.h"
+#include "swift/SIL/Test.h"
+#include "swift/SILOptimizer/Utils/CFGOptUtils.h"
+#include "swift/SILOptimizer/Utils/DebugOptUtils.h"
+#include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
+#include "swift/SILOptimizer/Utils/ValueLifetime.h"
+#include "llvm/ADT/Statistic.h"
+
+using namespace swift;
+
+//===----------------------------------------------------------------------===//
+//                           MARK: Local utilities
+//===----------------------------------------------------------------------===//
+
+static bool hasValueOwnership(SILValue value) {
+  return value->getOwnershipKind() == OwnershipKind::Guaranteed ||
+         value->getOwnershipKind() == OwnershipKind::Owned;
+}
+
+static SingleValueInstruction *asCopyOrMove(SILValue v) {
+  if (auto *copy = dyn_cast<CopyValueInst>(v))
+    return copy;
+  if (auto *move = dyn_cast<MoveValueInst>(v))
+    return move;
+  return nullptr;
+}
+
+/// Delete a chain of unused copies and moves leading to \p v.
+static void deleteCopyAndMoveChain(SILValue v, InstructionDeleter &deleter) {
+  while (auto *inst = asCopyOrMove(v)) {
+    if (!onlyHaveDebugUses(inst))
+      break;
+
+    v = inst->getOperand(CopyLikeInstruction::Src);
+    LLVM_DEBUG(llvm::dbgs() << "  Deleting " << *inst);
+    ++NumCopiesAndMovesEliminated;
+    deleter.forceDelete(inst);
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//                        MARK: Rewrite borrow scopes
+//===----------------------------------------------------------------------===//
+
+/// Does this instruction forward ownership, and can it be hoisted out of a
+/// borrow scope or sunk to its uses?
+///
+/// Currently requires the first operand to forward ownership.
+///
+/// Handles:
+///   OwnershipForwardingConversionInst (all kinds of ref casts)
+///   OwnershipForwardingMultipleValueInstruction
+///     (DestructureStruct, DestructureTuple)
+///   FirstArgOwnershipForwardingSingleValueInst
+///     (Object, Enum, UncheckedEnumData, Open/InitExistentialRef,
+///      MarkDependence)
+///
+/// TODO:
+///   Enum, InitExistential, MarkDependence
+///   Struct, Tuple
+///   SelectEnum, SwitchEnum, CheckCastBranch
+bool OSSACanonicalizeGuaranteed::isRewritableOSSAForward(SILInstruction *inst) {
+  if (!inst->isTriviallyDuplicatable())
+    return false;
+
+  // TODO: check other operands for dominance and even attempt to hoist them.
+  if (inst->getNumOperands() != 1)
+    return false;
+
+  if (!isa<OwnershipForwardingSingleValueInstruction>(inst) &&
+      !isa<OwnershipForwardingMultipleValueInstruction>(inst))
+    return false;
+
+  Operand *forwardedOper = &inst->getOperandRef(0);
+  // Trivial conversions do not need to be hoisted out of a borrow scope.
+  auto operOwnership = forwardedOper->getOperandOwnership();
+  if (operOwnership == OperandOwnership::TrivialUse)
+    return false;
+  // Don't mess with unowned conversions. They need to be copied immediately.
+  if (operOwnership != OperandOwnership::GuaranteedForwarding &&
+      operOwnership != OperandOwnership::ForwardingConsume) {
+    return false;
+  }
+  assert(operOwnership == OperandOwnership::GuaranteedForwarding ||
+         operOwnership == OperandOwnership::ForwardingConsume);
+
+  // Filter instructions that belong to a Forwarding*ValueInst mixin but
+  // cannot be converted to forward owned value (struct_extract).
+  if (!canOpcodeForwardOwnedValues(forwardedOper))
+    return false;
+
+  return true;
+}
+
+/// Return the root of a borrowed extended lifetime for \p def or invalid.
+///
+/// \p def may be any guaranteed value.
+SILValue OSSACanonicalizeGuaranteed::getCanonicalBorrowedDef(SILValue def) {
+  while (true) {
+    if (def->getOwnershipKind() != OwnershipKind::Guaranteed)
+      break;
+
+    if (auto borrowedVal = BorrowedValue(def)) {
+      // Any def's that aren't filtered out here must be handled by
+      // computeBorrowLiveness.
+      switch (borrowedVal.kind) {
+      case BorrowedValueKind::Invalid:
+        llvm_unreachable("Using invalid case?!");
+      case BorrowedValueKind::SILFunctionArgument:
+      case BorrowedValueKind::BeginBorrow:
+        return def;
+
+      case BorrowedValueKind::LoadBorrow:
+      case BorrowedValueKind::Phi:
+      case BorrowedValueKind::BeginApplyToken:
+        break;
+      }
+    }
+    // Look through hoistable guaranteed forwarding instructions on the
+    // use-def chain.
+    SILInstruction *defInst = def->getDefiningInstruction();
+    if (!defInst)
+      break;
+
+    if (!OSSACanonicalizeGuaranteed::isRewritableOSSAForward(defInst))
+      break;
+
+    def = defInst->getOperand(0);
+  }
+  return SILValue();
+}
+
+bool OSSACanonicalizeGuaranteed::computeBorrowLiveness() {
+  switch (borrowedValue.kind) {
+  case BorrowedValueKind::Invalid:
+    llvm_unreachable("Used invalid");
+  case BorrowedValueKind::SILFunctionArgument:
+    // For efficiency, function arguments skip liveness.
+    return true;
+  case BorrowedValueKind::LoadBorrow:
+  case BorrowedValueKind::Phi:
+    // TODO: Canonicalize load_borrow scope and phi once consolidateBorrowScope
+    // can handle persistentCopies.
+    return false;
+  case BorrowedValueKind::BeginBorrow:
+  case BorrowedValueKind::BeginApplyToken:
+    break;
+  }
+  // Note that there is no need to look through any reborrows. The reborrowed
+  // value is considered a separate lifetime for canonicalization. Any copies of
+  // the reborrowed value will not be rewritten when canonicalizing the current
+  // borrow scope because they are "hidden" behind the reborrow.
+  borrowedValue.visitLocalScopeEndingUses([this](Operand *use) {
+    liveness->updateForUse(use->getUser(), /*lifetimeEnding*/ true);
+    return true;
+  });
+  return true;
+}
+
+/// Return the source of a use within a borrow scope. This is the use-def
+/// equivalent to the logic in visitBorrowScopeUses that recurses through
+/// copies. The use-def and def-use logic must be consistent.
+SILValue OSSACanonicalizeGuaranteed::findDefInBorrowScope(SILValue value) {
+  while (auto *inst = asCopyOrMove(value)) {
+    auto *copy = dyn_cast<CopyValueInst>(inst);
+    if (copy && isPersistentCopy(copy))
+      return copy;
+
+    value = inst->getOperand(0);
+  }
+  return value;
+}
+
+/// Visit all extended uses within the borrow scope, looking through copies and
+/// moves. Call visitUse for uses which could potentially be outside the borrow
+/// scope. Call visitForwardingUse for hoistable forwarding operations which
+/// could potentially be inside the borrow scope.
+///
+/// The visitor may or may not be able to determine which uses are outside the
+/// scope, but it can filter uses that are definitely within the scope. For
+/// example, guaranteed uses and uses in live-out blocks must both be within
+/// the scope.
+///
+/// This def-use traversal is similar to findExtendedTransitiveGuaranteedUses(),
+/// however, to cover the canonical lifetime, it looks through copies. It also
+/// considers uses within the introduced borrow scope itself (instead of simply
+/// visiting the scope-ending uses). It does not, however, look into nested
+/// borrow scopes uses, since nested scopes are canonicalized independently.
+///
+/// \p innerValue is either the initial begin_borrow, or a forwarding operation
+/// within the borrow scope.
+template <typename Visitor>
+bool OSSACanonicalizeGuaranteed::visitBorrowScopeUses(SILValue innerValue,
+                                                      Visitor &visitor) {
+  // defUseWorklist is used recursively here.
+  // This avoids revisiting uses in case we ever recurse through
+  // both structs and destructures.
+  unsigned defUseStart = defUseWorklist.size();
+  defUseWorklist.insert(innerValue);
+  while (defUseStart < defUseWorklist.size()) {
+    SILValue value = defUseWorklist.pop();
+    // Gather the uses before updating any of them.
+    // 'value' may be deleted in this loop after rewriting its last use.
+    // 'use' may become invalid after processing its user.
+
+    SmallVector<Operand *, 4> uses(value->getUses());
+    for (auto *use : uses) {
+      auto *user = use->getUser();
+      // Incidental uses, such as debug_value may be deleted before they can be
+      // processed. Their user will now be nullptr. This means that value
+      // is dead, so just bail.
+      if (!user)
+        break;
+
+      // Recurse through copies and moves.
+      if (auto *copy = dyn_cast<CopyValueInst>(user)) {
+        if (!isPersistentCopy(copy)) {
+          defUseWorklist.insert(copy);
+          continue;
+        }
+      } else if (auto *move = dyn_cast<MoveValueInst>(user)) {
+        if (!move->isLexical() || innerValue->isLexical()) {
+          defUseWorklist.insert(move);
+          continue;
+        }
+      }
+      // Note: debug_value uses are handled like normal uses here. If they are
+      // inner uses, they remain. If they are outer uses, then they will be
+      // stripped if needed when the outer copy or persistent copy is
+      // canonicalized.
+      switch (use->getOperandOwnership()) {
+      case OperandOwnership::NonUse:
+        break;
+      case OperandOwnership::TrivialUse:
+        llvm_unreachable("this operand cannot handle ownership");
+
+      case OperandOwnership::InteriorPointer:
+      case OperandOwnership::AnyInteriorPointer:
+      case OperandOwnership::EndBorrow:
+      case OperandOwnership::Reborrow:
+        // Ignore uses that must be within the borrow scope.
+        // Rewriting does not look through reborrowed values--it considers them
+        // part of a separate lifetime.
+        break;
+
+      case OperandOwnership::ForwardingUnowned:
+      case OperandOwnership::PointerEscape:
+        // Pointer escapes are only allowed if they use the guaranteed value,
+        // which means that the escaped value must be confined to the current
+        // borrow scope.
+        if (use->get()->getOwnershipKind() != OwnershipKind::Guaranteed &&
+            !isa<SILFunctionArgument>(borrowedValue.value)) {
+          return false;
+        }
+        if (!visitor.visitUse(use)) {
+          return false;
+        }
+        break;
+
+      case OperandOwnership::GuaranteedForwarding:
+      case OperandOwnership::ForwardingConsume:
+        if (OSSACanonicalizeGuaranteed::isRewritableOSSAForward(user)) {
+          if (!visitor.visitForwardingUse(use)) {
+            return false;
+          }
+          break;
+        }
+        LLVM_FALLTHROUGH;
+
+      case OperandOwnership::Borrow:
+      case OperandOwnership::InstantaneousUse:
+      case OperandOwnership::UnownedInstantaneousUse:
+      case OperandOwnership::BitwiseEscape:
+      case OperandOwnership::DestroyingConsume:
+        if (!visitor.visitUse(use)) {
+          return false;
+        }
+        break;
+      } // end switch OperandOwnership
+    }
+  } // end def-use traversal
+  return true;
+}
+
+namespace {
+
+using OuterUsers = OSSACanonicalizeGuaranteed::OuterUsers;
+
+/// Find all potential outer uses within a borrow scope.
+///
+/// Implements visitBorrowScopeUses<Visitor>
+class FindBorrowScopeUses {
+  OSSACanonicalizeGuaranteed &scope;
+
+  /// useInsts are the potentially outer use instructions. This set is built up
+  /// recursively. It is pared down to only the outer uses outside this class by
+  /// filterOuterBorrowUseInsts.
+  OuterUsers useInsts;
+
+public:
+  FindBorrowScopeUses(OSSACanonicalizeGuaranteed &scope) : scope(scope) {}
+
+  std::optional<OuterUsers> findUses() && {
+    scope.beginVisitBorrowScopeUses();
+    if (!scope.visitBorrowScopeUses(scope.getBorrowedValue().value, *this))
+      return std::nullopt;
+
+    return std::move(useInsts);
+  }
+
+  bool visitUse(Operand *use) {
+    // A guaranteed use can never be outside this borrow scope
+    if (use->get()->getOwnershipKind() == OwnershipKind::Guaranteed)
+      return true;
+
+    auto *user = use->getUser();
+    if (!isUserInLiveOutBlock(user)) {
+      useInsts.insert(user);
+    }
+    if (auto borrowingOper = BorrowingOperand(use)) {
+      // For borrows, record the scope-ending instructions to outer use
+      // points. Note: The logic in filterOuterBorrowUseInsts that checks
+      // whether a borrow scope is an outer use must visit the same set of uses.
+      if (!borrowingOper.visitExtendedScopeEndingUses([&](Operand *endBorrow) {
+            auto *endInst = endBorrow->getUser();
+            if (!isUserInLiveOutBlock(endInst)) {
+              useInsts.insert(endInst);
+            }
+            return true;
+          })) {
+        // Bail out on dead borrow scopes and scopes with unknown uses.
+        return false;
+      }
+    }
+    return true;
+  }
+
+  // Recurse through forwards.
+  bool visitForwardingUse(Operand *use) {
+    auto *user = use->getUser();
+    if (!isUserInLiveOutBlock(user)) {
+      useInsts.insert(user);
+    }
+    for (auto result : user->getResults()) {
+      if (hasValueOwnership(result)) {
+        if (!scope.visitBorrowScopeUses(result, *this))
+          return false;
+      }
+    }
+    return true;
+  }
+
+protected:
+  bool isUserInLiveOutBlock(SILInstruction *user) {
+    return (scope.getLiveness().getBlockLiveness(user->getParent()) ==
+            PrunedLiveBlocks::LiveOut);
+    return false;
+  };
+};
+
+} // namespace
+
+/// Erase users from \p outerUseInsts that are actually within the borrow scope.
+void OSSACanonicalizeGuaranteed::filterOuterBorrowUseInsts(
+    OuterUsers &outerUseInsts) {
+  auto *beginBorrow = cast<BeginBorrowInst>(borrowedValue.value);
+  SmallVector<SILInstruction *, 4> scopeEndingInsts;
+  BorrowedValue(beginBorrow).getLocalScopeEndingInstructions(scopeEndingInsts);
+  blockWorklist.clear();
+  // Remove outer uses that occur before the end of the borrow scope by
+  // reverse iterating from the end_borrow.
+  auto scanBlock = [&](SILBasicBlock *bb, SILBasicBlock::iterator endIter) {
+    auto beginIter = bb->begin();
+    if (bb == beginBorrow->getParent()) {
+      beginIter = std::next(beginBorrow->getIterator());
+    } else {
+      blockWorklist.insert(bb);
+    }
+    for (auto instIter = endIter; instIter != beginIter;) {
+      --instIter;
+      outerUseInsts.erase(&*instIter);
+    }
+  };
+  for (auto *scopeEnd : scopeEndingInsts) {
+    scanBlock(scopeEnd->getParent(), std::next(scopeEnd->getIterator()));
+  }
+  // This worklist is also a visited set, so we never pop the entries.
+  while (auto *bb = blockWorklist.pop()) {
+    for (auto *predBB : bb->getPredecessorBlocks()) {
+      scanBlock(predBB, predBB->end());
+    }
+  }
+}
+
+namespace {
+
+/// Remove redundant copies/destroys within a borrow scope.
+///
+/// The visitor callbacks must always return true since this rewrites in-place.
+class RewriteInnerBorrowUses {
+  OSSACanonicalizeGuaranteed &scope;
+
+public:
+  RewriteInnerBorrowUses(OSSACanonicalizeGuaranteed &scope) : scope(scope) {}
+
+  OSSACanonicalizeGuaranteed &getScope() const { return scope; }
+
+  // Implements visitBorrowScopeUses<Visitor>
+  bool visitUse(Operand *use) {
+    auto *user = use->getUser();
+    SILValue value = use->get();
+    // destroys are never needed within a borrow scope.
+    if (isa<DestroyValueInst>(user)) {
+      scope.getDeleter().forceDelete(user);
+      deleteCopyAndMoveChain(value, scope.getDeleter());
+      return true;
+    }
+    SILValue def = scope.findDefInBorrowScope(value);
+    if (use->isConsuming()) {
+      if (use->get()->getType().isMoveOnly()) {
+        // Can't produce a copy of a non-copyable value on demand.  Bail out.
+        return false;
+      }
+      // All in-scope consuming uses need a unique copy in the same block.
+      auto *copy = dyn_cast<CopyValueInst>(use->get());
+      if (copy && copy->hasOneUse() && copy->getParent() == user->getParent()) {
+        value = copy->getOperand();
+        copy->setOperand(def);
+      } else {
+        use->set(def);
+        copyLiveUse(use, scope.getCallbacks());
+      }
+      deleteCopyAndMoveChain(value, scope.getDeleter());
+      return true;
+    }
+    // Non-consuming use.
+    use->set(def);
+    deleteCopyAndMoveChain(value, scope.getDeleter());
+    return true;
+  }
+
+  // Recurse through forwards.
+  //
+  // Implements visitBorrowScopeUses<Visitor>
+  bool visitForwardingUse(Operand *use) {
+    auto *user = use->getUser();
+    assert(OSSACanonicalizeGuaranteed::isRewritableOSSAForward(user));
+
+    for (auto result : user->getResults()) {
+      if (!hasValueOwnership(result)) {
+        continue;
+      }
+      if (!scope.visitBorrowScopeUses(result, *this)) {
+        return false;
+      }
+    }
+    // Update this operand bypassing any copies.
+    SILValue value = use->get();
+    use->set(scope.findDefInBorrowScope(value));
+    ForwardingOperand(use).setForwardingOwnershipKind(
+        OwnershipKind::Guaranteed);
+    deleteCopyAndMoveChain(value, scope.getDeleter());
+    return true;
+  }
+};
+
+/// Generate copies outside this borrow scope, hoist forwarding operations,
+/// rewrite the operands of uses outside the scope, and record the outer uses
+/// that are consumes.
+///
+/// Each hoisted forwarding operation instantiates a new instance of this
+/// visitor. They are rewritten separately.
+///
+/// Implements visitBorrowScopeUses<Visitor>
+///
+/// The visitor callbacks must always return true since this rewrites in-place.
+class RewriteOuterBorrowUses {
+  OSSACanonicalizeGuaranteed &scope;
+
+  RewriteInnerBorrowUses &innerRewriter;
+
+  const OuterUsers &outerUseInsts;
+
+  /// Map values inside the borrow scope to cloned-and-copied values outside the
+  /// borrow scope.
+  using InnerToOuterMap = llvm::SmallDenseMap<SILValue, SILValue, 8>;
+  InnerToOuterMap &innerToOuterMap;
+
+  // Outer uses specific to the current incomingValue, including hoisted
+  // forwarding instructions, which are not part of outerUseInsts.
+  SmallVector<Operand *, 4> consumingUses;
+  SmallPtrSet<SILInstruction *, 4> unclaimedConsumingUsers;
+
+  RewriteOuterBorrowUses(RewriteInnerBorrowUses &innerRewriter,
+                         const OuterUsers &outerUseInsts,
+                         InnerToOuterMap &innerToOuterMap)
+      : scope(innerRewriter.getScope()), innerRewriter(innerRewriter),
+        outerUseInsts(outerUseInsts), innerToOuterMap(innerToOuterMap) {}
+
+public:
+  static void rewrite(BeginBorrowInst *beginBorrow,
+                      OSSACanonicalizeGuaranteed &scope,
+                      const OuterUsers &outerUseInsts) {
+
+    SILBuilderWithScope builder(beginBorrow);
+    auto loc = RegularLocation::getAutoGeneratedLocation(beginBorrow->getLoc());
+    auto *outerCopy =
+        createOuterCopy(beginBorrow->getOperand(), builder, loc, scope);
+
+    llvm::SmallDenseMap<SILValue, SILValue, 8> innerToOuterMap;
+    innerToOuterMap[beginBorrow] = outerCopy;
+
+    RewriteInnerBorrowUses innerRewriter(scope);
+    RewriteOuterBorrowUses rewriter(innerRewriter, outerUseInsts,
+                                    innerToOuterMap);
+    scope.beginVisitBorrowScopeUses();
+    auto outerVal = rewriter.recursivelyRewriteOuterUses(beginBorrow);
+    assert(outerVal == outerCopy);
+  }
+
+  // Implements visitBorrowScopeUses<Visitor>
+  bool visitUse(Operand *use) {
+    auto *user = use->getUser();
+    if (outerUseInsts.count(user)) {
+      rewriteOuterUse(use);
+      return true;
+    }
+    // If this use begins a borrow scope, check if any of the scope ending
+    // instructions are outside the current scope (this can happen if any copy
+    // has occurred on the def-use chain within the current scope).
+    if (auto borrowingOper = BorrowingOperand(use)) {
+      if (!borrowingOper.visitExtendedScopeEndingUses([&](Operand *endBorrow) {
+            return !outerUseInsts.count(endBorrow->getUser());
+          })) {
+        rewriteOuterUse(use);
+        return true;
+      }
+    }
+    innerRewriter.visitUse(use);
+    return true;
+  }
+
+  // Recurse through forwards.
+  //
+  // Implements visitBorrowScopeUses<Visitor>
+  bool visitForwardingUse(Operand *use) {
+    auto *user = use->getUser();
+    assert(OSSACanonicalizeGuaranteed::isRewritableOSSAForward(user));
+    if (outerUseInsts.count(user)) {
+      rewriteOuterUse(use);
+      return true;
+    }
+
+    // Process transitive users and add this forwarding operation to
+    // outerUseInsts if any outer uses were found.
+    SILInstruction *outerClone = nullptr;
+    for (auto result : user->getResults()) {
+      if (!hasValueOwnership(result)) {
+        continue;
+      }
+      RewriteOuterBorrowUses rewriter(innerRewriter, outerUseInsts,
+                                      innerToOuterMap);
+      auto outerVal = rewriter.recursivelyRewriteOuterUses(result);
+      if (outerVal)
+        outerClone = outerVal->getDefiningInstruction();
+    }
+    // Record the forwarded operand of this hoisted instruction as an outer use.
+    if (outerClone) {
+      recordOuterUse(&outerClone->getOperandRef(0));
+    }
+    // If it's not already dead, update this operand bypassing any copies.
+    SILValue innerValue = use->get();
+    if (scope.getDeleter().deleteIfDead(user, /*fixLifetime=*/false)) {
+      LLVM_DEBUG(llvm::dbgs() << "  Deleted " << *user);
+    } else {
+      use->set(scope.findDefInBorrowScope(use->get()));
+      ForwardingOperand(use).setForwardingOwnershipKind(
+          OwnershipKind::Guaranteed);
+    }
+    deleteCopyAndMoveChain(innerValue, scope.getDeleter());
+    return true;
+  }
+
+protected:
+  // Create a copy for outer uses of the borrow scope introduced by
+  // currentDef. This copy should only be used by outer uses in the same block
+  // as the borrow scope.
+  //
+  // To use an existing outer copy, we could find its earliest consume. But the
+  // new copy will immediately canonicalized and a canonical begin_borrow scope
+  // have no outer uses of its first block.
+  static CopyValueInst *createOuterCopy(SILValue incomingValue,
+                                        SILBuilder &builder, SILLocation loc,
+                                        OSSACanonicalizeGuaranteed &scope) {
+    auto *copy = builder.createCopyValue(loc, incomingValue);
+    scope.getCallbacks().createdNewInst(copy);
+    scope.recordOuterCopy(copy);
+
+    ++NumCopiesGenerated;
+    LLVM_DEBUG(llvm::dbgs() << "  Outer copy " << *copy);
+
+    return copy;
+  }
+
+  SILValue recursivelyRewriteOuterUses(SILValue innerValue) {
+    bool succeed = scope.visitBorrowScopeUses(innerValue, *this);
+    assert(succeed && "should be filtered by FindBorrowScopeUses");
+
+    auto iter = innerToOuterMap.find(innerValue);
+    if (iter == innerToOuterMap.end()) {
+      return SILValue();
+    }
+    SILValue outerValue = iter->second;
+    cleanupOuterValue(outerValue);
+    return outerValue;
+  }
+
+  void recordOuterUse(Operand *use) {
+    if (use->isLifetimeEnding()) {
+      consumingUses.push_back(use);
+      unclaimedConsumingUsers.insert(use->getUser());
+    }
+  };
+
+  void rewriteOuterUse(Operand *use) {
+    LLVM_DEBUG(llvm::dbgs() << "  Use of outer copy " << *use->getUser());
+
+    SILValue innerValue = use->get();
+    SILValue outerValue = createOuterValues(innerValue);
+
+    use->set(outerValue);
+
+    deleteCopyAndMoveChain(innerValue, scope.getDeleter());
+
+    recordOuterUse(use);
+  };
+
+  SILValue createOuterValues(SILValue innerValue);
+
+  void cleanupOuterValue(SILValue outerValue);
+};
+
+} // namespace
+
+// Incrementally create a def-use chain outside the current borrow scope for
+// all instructions between currentDef and \p innerValue, where \p innerValue
+// has at least one use outside the borrow scope.
+SILValue RewriteOuterBorrowUses::createOuterValues(SILValue innerValue) {
+  // Poke through the copies just like rewriteOuterBorrowUsesAndFindConsumes
+  // does on the def-use side.
+  while (auto *copy = dyn_cast<CopyValueInst>(innerValue)) {
+    innerValue = copy->getOperand();
+  }
+  auto iter = innerToOuterMap.find(innerValue);
+  if (iter != innerToOuterMap.end()) {
+    return iter->second;
+  }
+  auto *innerInst = innerValue->getDefiningInstruction();
+  assert(OSSACanonicalizeGuaranteed::isRewritableOSSAForward(innerInst));
+  SILValue incomingInnerVal = innerInst->getOperand(0);
+
+  auto incomingOuterVal = createOuterValues(incomingInnerVal);
+
+  auto *insertPt = innerValue->getDefiningInsertionPoint();
+  auto *clone = innerInst->clone(insertPt);
+  scope.getCallbacks().createdNewInst(clone);
+  Operand *use = &clone->getOperandRef(0);
+  use->set(incomingOuterVal);
+  ForwardingOperand(use).setForwardingOwnershipKind(OwnershipKind::Owned);
+
+  LLVM_DEBUG(llvm::dbgs() << "  Hoisted forward " << *clone);
+
+  for (unsigned idx = 0, endIdx = clone->getNumResults(); idx < endIdx; ++idx) {
+    innerToOuterMap[innerInst->getResult(idx)] = clone->getResult(idx);
+  }
+  return innerToOuterMap[innerValue];
+}
+
+// Insert destroys on the outer copy's or forwarding consume's lifetime
+// frontier, or claim a existing consumes. Insert copies for unclaimed consumes.
+void RewriteOuterBorrowUses::cleanupOuterValue(SILValue outerValue) {
+  // Gather outerValue's transitive ownership uses for ValueLifetimeAnalysis.
+  SmallVector<SILInstruction *, 4> outerUses;
+  for (Operand *use : outerValue->getUses()) {
+    outerUses.push_back(use->getUser());
+    if (auto borrowingOper = BorrowingOperand(use)) {
+      borrowingOper.visitExtendedScopeEndingUses([&](Operand *endBorrow) {
+        outerUses.push_back(endBorrow->getUser());
+        return true;
+      });
+    }
+  }
+  ValueLifetimeAnalysis lifetimeAnalysis(outerValue.getDefiningInstruction(),
+                                         outerUses);
+
+  auto createDestroy = [&](SILBuilder &b, SILLocation loc) {
+    auto *dvi = b.createDestroyValue(loc, outerValue);
+    scope.getCallbacks().createdNewInst(dvi);
+  };
+  if (outerUses.empty()) {
+    SILBuilder b(outerValue->getNextInstruction());
+    createDestroy(b, outerValue.getLoc());
+    return;
+  }
+
+  ValueLifetimeBoundary boundary;
+  lifetimeAnalysis.computeLifetimeBoundary(boundary);
+
+  for (auto *boundaryEdge : boundary.boundaryEdges) {
+    if (DeadEndBlocks::triviallyEndsInUnreachable(boundaryEdge))
+      continue;
+    auto insertPt = boundaryEdge->begin();
+    auto *dvi = SILBuilderWithScope(insertPt).createDestroyValue(
+        insertPt->getLoc(), outerValue);
+    scope.getCallbacks().createdNewInst(dvi);
+  }
+
+  for (SILInstruction *lastUser : boundary.lastUsers) {
+    if (unclaimedConsumingUsers.erase(lastUser))
+      continue;
+
+    SILBuilderWithScope::insertAfter(
+        lastUser, [&](SILBuilder &b) { createDestroy(b, lastUser->getLoc()); });
+  }
+  // Add copies for consuming users of outerValue.
+  for (auto *use : consumingUses) {
+    // If the user is still in the unclaimedConsumingUsers set, then it does not
+    // end the outer copy's lifetime and therefore requires a copy. Only one
+    // operand can be claimed as ending the lifetime, so return its user to the
+    // unclaimedConsumingUsers set after skipping the first copy.
+    auto iterAndInserted = unclaimedConsumingUsers.insert(use->getUser());
+    if (!iterAndInserted.second) {
+      copyLiveUse(use, scope.getCallbacks());
+      scope.recordOuterCopy(cast<CopyValueInst>(use->get()));
+    }
+  }
+}
+
+// If this succeeds, then all uses of the borrowed value outside the borrow
+// scope will be rewritten to use an outer copy, and all remaining uses of the
+// borrowed value will be confined to the borrow scope.
+//
+// TODO: Canonicalize multi-block borrow scopes, load_borrow scope, and phi
+// borrow scopes by adding one copy per block to persistentCopies for
+// each block that dominates an outer use.
+bool OSSACanonicalizeGuaranteed::consolidateBorrowScope() {
+  OuterUsers outerUseInsts;
+  if (!isa<SILFunctionArgument>(borrowedValue.value)) {
+    // getCanonicalCopiedDef ensures that if currentDef is a guaranteed value,
+    // then it is a borrow scope introducer.
+    assert(borrowedValue.isLocalScope());
+
+    // Gather all potential outer uses before rewriting any to avoid scanning
+    // any basic block more than once.
+    std::optional<OuterUsers> outerUsers =
+        FindBorrowScopeUses(*this).findUses();
+    if (!outerUsers)
+      return false;
+
+    outerUseInsts = std::move(outerUsers).value();
+
+    filterOuterBorrowUseInsts(outerUseInsts);
+  }
+  // If there are no outer uses, then canonicalization is a simple matter of
+  // removing all the destroys and rewriting the copies.
+  if (outerUseInsts.empty()) {
+    RewriteInnerBorrowUses innerRewriter(*this);
+    beginVisitBorrowScopeUses(); // reset the def/use worklist
+    return visitBorrowScopeUses(borrowedValue.value, innerRewriter);
+  }
+  LLVM_DEBUG(llvm::dbgs() << "  Outer uses:\n";
+             for (SILInstruction *inst
+                  : outerUseInsts) { llvm::dbgs() << "    " << *inst; });
+
+  RewriteOuterBorrowUses::rewrite(cast<BeginBorrowInst>(borrowedValue.value),
+                                  *this, outerUseInsts);
+  return true;
+}
+
+//===----------------------------------------------------------------------===//
+//                  MARK: Top-Level OSSACanonicalizeGuaranteed
+//===----------------------------------------------------------------------===//
+
+bool OSSACanonicalizeGuaranteed::canonicalizeFunctionArgument(
+    SILFunctionArgument *arg) {
+  BorrowedValue borrow(arg);
+  if (!borrow)
+    return false;
+
+  initBorrow(borrow);
+
+  LLVM_DEBUG(llvm::dbgs() << "*** Canonicalize Borrow: " << borrowedValue);
+
+  RewriteInnerBorrowUses innerRewriter(*this);
+  beginVisitBorrowScopeUses(); // reset the def/use worklist
+
+  return visitBorrowScopeUses(borrowedValue.value, innerRewriter);
+}
+
+namespace swift::test {
+// Arguments:
+// - SILFunctionArgument: function argument to canonicalize
+// Dumps:
+// - function after argument canonicalization
+static FunctionTest CanonicalizeFunctionArgumentTest(
+    "canonicalize_function_argument",
+    [](auto &function, auto &arguments, auto &test) {
+      auto *argument = cast<SILFunctionArgument>(arguments.takeBlockArgument());
+      InstructionDeleter deleter;
+      OSSACanonicalizeGuaranteed canonicalizer(&function, deleter);
+      canonicalizer.canonicalizeFunctionArgument(argument);
+      function.print(llvm::outs());
+    });
+} // end namespace swift::test
+
+/// Canonicalize a worklist of extended lifetimes. This iterates after rewriting
+/// borrow scopes to handle new outer copies and new owned lifetimes from
+/// forwarding operations.
+bool OSSACanonicalizeGuaranteed::canonicalizeBorrowScope(
+    BorrowedValue borrowedValue) {
+  BitfieldRef<SSAPrunedLiveness>::StackState livenessBitfieldContainer(
+      liveness, function);
+
+  LLVM_DEBUG(llvm::dbgs() << "*** Canonicalize Borrow: " << borrowedValue);
+
+  initBorrow(borrowedValue);
+
+  if (!computeBorrowLiveness())
+    return false;
+
+  // Set outerCopy and persistentCopies and rewrite uses
+  // outside the scope.
+  if (!consolidateBorrowScope())
+    return false;
+
+  return true;
+}
+
+namespace swift::test {
+// Arguments:
+// - SILValue: value to canonicalize
+// Dumps:
+// - function after value canonicalization
+static FunctionTest OSSACanonicalizeGuaranteedTest(
+    "ossa_canonicalize_guaranteed",
+    [](auto &function, auto &arguments, auto &test) {
+      auto value = arguments.takeValue();
+      auto borrowedValue = BorrowedValue(value);
+      assert(borrowedValue && "specified value isn't a BorrowedValue!?");
+      InstructionDeleter deleter;
+      OSSACanonicalizeGuaranteed canonicalizer(value->getFunction(), deleter);
+      canonicalizer.canonicalizeBorrowScope(borrowedValue);
+      function.print(llvm::outs());
+    });
+} // end namespace swift::test
diff --git a/lib/SILOptimizer/Utils/OSSACanonicalizeOwned.cpp b/lib/SILOptimizer/Utils/OSSACanonicalizeOwned.cpp
new file mode 100644
index 0000000000000..339e0abb9f931
--- /dev/null
+++ b/lib/SILOptimizer/Utils/OSSACanonicalizeOwned.cpp
@@ -0,0 +1,1523 @@
+//===-- OSSACanonicalizeOwned.cpp - Canonicalize OSSA value lifetimes --===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// This top-level API rewrites the extended lifetime of a SILValue:
+///
+///     bool OSSACanonicalizeOwned::canonicalizeValueLifetime(SILValue def)
+///
+/// Each time it's called on a single OSSA value, `def`, it performs four
+/// steps:
+///
+/// 1. Compute "pruned" liveness of def and its copies, ignoring original
+///    destroys. Initializes `liveness`.
+///
+/// 2. Find the "original" boundary of liveness using
+///    PrunedLiveness::computeBoundary.
+///
+/// 3. (Optional) At Onone, extend liveness up to original extent when possible
+///    without incurring extra copies.
+///
+/// 4. Find the "extended" boundary of liveness by walking out from the boundary
+///    computed by PrunedLiveness out to destroys which aren't separated from
+///    the original destory by "interesting" instructions.
+///
+/// 5. Initializes `consumes` and inserts new destroy_value instructions.
+///
+/// 6. Rewrite `def`s original copies and destroys, inserting new copies where
+///    needed. Deletes original copies and destroys and inserts new copies.
+///
+/// See OSSACanonicalizeOwned.h for examples.
+///
+/// TODO: Canonicalization currently bails out if any uses of the def has
+/// OperandOwnership::PointerEscape. Once project_box is protected by a borrow
+/// scope and mark_dependence is associated with an end_dependence, those will
+/// no longer be represented as PointerEscapes, and canonicalization will
+/// naturally work everywhere as intended. The intention is to keep the
+/// canonicalization algorithm as simple and robust, leaving the remaining
+/// performance opportunities contingent on fixing the SIL representation.
+///
+/// TODO: Replace BasicBlock SmallDenseMaps with inlined bits;
+/// see BasicBlockDataStructures.h.
+///
+/// TODO: This algorithm would be extraordinarily simple and cheap except for
+/// the following issues:
+///
+/// 1. Liveness is extended by any overlapping begin/end_access scopes. This
+/// avoids calling a destructor within an exclusive access. A simpler
+/// alternative would be to model all end_access instructions as deinit
+/// barriers, but that may significantly limit optimization.
+///
+/// 2. Liveness is extended out to original destroys to avoid spurious changes.
+///
+/// 3. In the Onone mode, liveness is preserved to its previous extent whenever
+/// doing so doesn't incur extra copies compared to what is done in the O mode.
+///
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "copy-propagation"
+
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeOwned.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/SIL/InstructionUtils.h"
+#include "swift/SIL/NodeDatastructures.h"
+#include "swift/SIL/OSSACompleteLifetime.h"
+#include "swift/SIL/OwnershipUtils.h"
+#include "swift/SIL/PrunedLiveness.h"
+#include "swift/SIL/Test.h"
+#include "swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h"
+#include "swift/SILOptimizer/Analysis/Reachability.h"
+#include "swift/SILOptimizer/PassManager/Transforms.h"
+#include "swift/SILOptimizer/Utils/CFGOptUtils.h"
+#include "swift/SILOptimizer/Utils/DebugOptUtils.h"
+#include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/ValueLifetime.h"
+#include "llvm/ADT/Statistic.h"
+
+using namespace swift;
+using llvm::SmallSetVector;
+
+llvm::Statistic swift::NumCopiesAndMovesEliminated = {
+    DEBUG_TYPE, "NumCopiesAndMovesEliminated",
+    "number of copy_value and move_value instructions removed"};
+
+llvm::Statistic swift::NumCopiesGenerated = {
+    DEBUG_TYPE, "NumCopiesGenerated",
+    "number of copy_value instructions created"};
+
+STATISTIC(NumDestroysEliminated,
+          "number of destroy_value instructions removed");
+STATISTIC(NumDestroysGenerated, "number of destroy_value instructions created");
+
+//===----------------------------------------------------------------------===//
+//                           MARK: General utilities
+//===----------------------------------------------------------------------===//
+
+template <typename... T, typename... U>
+static void diagnose(ASTContext &Context, SourceLoc loc, Diag<T...> diag,
+                     U &&...args) {
+  Context.Diags.diagnose(loc, diag, std::forward<U>(args)...);
+}
+
+/// Is \p instruction a destroy_value whose operand is \p def, or its
+/// transitive copy.
+static bool isDestroyOfCopyOf(SILInstruction *instruction, SILValue def) {
+  auto *destroy = dyn_cast<DestroyValueInst>(instruction);
+  if (!destroy)
+    return false;
+  auto destroyed = destroy->getOperand();
+  while (true) {
+    if (destroyed == def)
+      return true;
+    auto *copy = dyn_cast<CopyValueInst>(destroyed);
+    if (!copy)
+      break;
+    destroyed = copy->getOperand();
+  }
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// MARK: Step 1. Compute pruned liveness
+//===----------------------------------------------------------------------===//
+
+bool OSSACanonicalizeOwned::computeCanonicalLiveness() {
+  LLVM_DEBUG(llvm::dbgs() << "Computing canonical liveness from:\n";
+             getCurrentDef()->print(llvm::dbgs()));
+  SmallVector<unsigned, 8> indexWorklist;
+  ValueSet visitedDefs(getCurrentDef()->getFunction());
+  auto addDefToWorklist = [&](Def def) {
+    if (!visitedDefs.insert(def.value))
+      return;
+    discoveredDefs.push_back(def);
+    indexWorklist.push_back(discoveredDefs.size() - 1);
+  };
+  discoveredDefs.clear();
+  addDefToWorklist(Def::root(getCurrentDef()));
+  // Only the first level of reborrows need to be consider. All nested inner
+  // adjacent reborrows and phis are encapsulated within their lifetimes.
+  SILPhiArgument *arg;
+  if ((arg = dyn_cast<SILPhiArgument>(getCurrentDef())) && arg->isPhi()) {
+    visitInnerAdjacentPhis(arg, [&](SILArgument *reborrow) {
+      addDefToWorklist(Def::reborrow(reborrow));
+      return true;
+    });
+  }
+  while (!indexWorklist.empty()) {
+    auto index = indexWorklist.pop_back_val();
+    auto def = discoveredDefs[index];
+    auto value = def.value;
+    LLVM_DEBUG(llvm::dbgs() << "  Uses of value:\n";
+               value->print(llvm::dbgs()));
+
+    for (Operand *use : value->getUses()) {
+      LLVM_DEBUG(llvm::dbgs() << "    Use:\n";
+                 use->getUser()->print(llvm::dbgs()));
+
+      auto *user = use->getUser();
+      // Recurse through copies.
+      if (auto *copy = dyn_cast<CopyValueInst>(user)) {
+        // Don't recurse through copies of borrowed-froms or reborrows.
+        switch (def.kind) {
+        case Def::Root:
+        case Def::Copy:
+          addDefToWorklist(Def::copy(copy));
+          break;
+        case Def::Reborrow:
+        case Def::BorrowedFrom:
+          break;
+        }
+        continue;
+      }
+      if (auto *bfi = dyn_cast<BorrowedFromInst>(user)) {
+        addDefToWorklist(Def::borrowedFrom(bfi));
+        continue;
+      }
+      // Handle debug_value instructions separately.
+      if (pruneDebugMode) {
+        if (auto *dvi = dyn_cast<DebugValueInst>(user)) {
+          // Only instructions potentially outside current pruned liveness are
+          // interesting.
+          if (liveness->getBlockLiveness(dvi->getParent()) !=
+              PrunedLiveBlocks::LiveOut) {
+            recordDebugValue(dvi);
+          }
+          continue;
+        }
+      }
+      switch (use->getOperandOwnership()) {
+      case OperandOwnership::NonUse:
+        break;
+      case OperandOwnership::TrivialUse:
+        llvm_unreachable("this operand cannot handle ownership");
+
+      // Conservatively treat a conversion to an unowned value as a pointer
+      // escape. Is it legal to canonicalize ForwardingUnowned?
+      case OperandOwnership::ForwardingUnowned:
+      case OperandOwnership::PointerEscape:
+        LLVM_DEBUG(llvm::dbgs() << "      Value escaped! Giving up\n");
+        return false;
+      case OperandOwnership::InstantaneousUse:
+      case OperandOwnership::UnownedInstantaneousUse:
+      case OperandOwnership::BitwiseEscape:
+        liveness->updateForUse(user, /*lifetimeEnding*/ false);
+        break;
+      case OperandOwnership::ForwardingConsume:
+        recordConsumingUse(use);
+        liveness->updateForUse(user, /*lifetimeEnding*/ true);
+        break;
+      case OperandOwnership::DestroyingConsume:
+        if (isDestroyOfCopyOf(user, getCurrentDef())) {
+          destroys.insert(user);
+        } else {
+          // destroy_value of a transitive copy of the currentDef does not
+          // force pruned liveness (but store etc. does).
+
+          // Even though this instruction is a DestroyingConsume of its operand,
+          // if it's a destroy_value whose operand is not a transitive copy of
+          // currentDef, then it's just ending an implicit borrow of currentDef,
+          // not consuming it.
+          auto lifetimeEnding = !isa<DestroyValueInst>(user);
+          liveness->updateForUse(user, lifetimeEnding);
+        }
+        recordConsumingUse(use);
+        break;
+      case OperandOwnership::Borrow:
+        if (liveness->updateForBorrowingOperand(use) !=
+            InnerBorrowKind::Contained) {
+          LLVM_DEBUG(llvm::dbgs()
+                     << "      Inner borrow can't be contained! Giving up\n");
+          return false;
+        }
+        break;
+      case OperandOwnership::InteriorPointer:
+      case OperandOwnership::AnyInteriorPointer:
+        if (liveness->checkAndUpdateInteriorPointer(use) !=
+            AddressUseKind::NonEscaping) {
+          LLVM_DEBUG(llvm::dbgs()
+                     << "      Inner address use is escaping! Giving up\n");
+          return false;
+        }
+        break;
+      case OperandOwnership::GuaranteedForwarding:
+      case OperandOwnership::EndBorrow:
+        // Guaranteed values are exposed by inner adjacent reborrows. If user is
+        // a guaranteed phi (GuaranteedForwarding), then the owned lifetime
+        // either dominates it or its lifetime ends at an outer adjacent
+        // reborrow. Only instructions that end the reborrow lifetime should
+        // actually affect liveness of the outer owned value.
+        liveness->updateForUse(user, /*lifetimeEnding*/ false);
+        break;
+      case OperandOwnership::Reborrow:
+        BranchInst *branch = cast<BranchInst>(user);
+        // This is a cheap variation on visitEnclosingDef. We already know that
+        // getCurrentDef() is the enclosing def for this use. If the reborrow's
+        // has a enclosing def is an outer adjacent phi then this branch must
+        // consume getCurrentDef() as the outer phi operand.
+        if (is_contained(branch->getOperandValues(), getCurrentDef())) {
+          // An adjacent phi consumes the value being reborrowed. Although this
+          // use doesn't end the lifetime, this branch does end the lifetime by
+          // consuming the owned value.
+          liveness->updateForUse(branch, /*lifetimeEnding*/ true);
+          break;
+        }
+        // No adjacent phi consumes the value.  This use is not lifetime ending.
+        liveness->updateForUse(branch, /*lifetimeEnding*/ false);
+        // This branch reborrows a guaranteed phi whose lifetime is dependent on
+        // currentDef.  Uses of the reborrowing phi extend liveness.
+        auto *reborrow = PhiOperand(use).getValue();
+        addDefToWorklist(Def::reborrow(reborrow));
+        break;
+      }
+    }
+  }
+  return true;
+}
+
+/// Extend liveness to the availability boundary of currentDef.  Even if a copy
+/// is consumed on a path to the dead-end, if the def stays live through to the
+/// dead-end, its lifetime must not be shrunk back from it (eventually we'll
+/// support shrinking it back to deinit barriers).
+///
+/// Example:
+///     %def is lexical
+///     %copy = copy_value %def
+///     consume %copy
+///     apply %foo() // deinit barrier
+///     // Must extend lifetime of %def up to this point per language rules.
+///     unreachable
+void OSSACanonicalizeOwned::extendLexicalLivenessToDeadEnds() {
+  // TODO: OSSACompleteLifetime: Once lifetimes are always complete, delete
+  //                               this method.
+  SmallVector<SILBasicBlock *, 32> directDiscoverdBlocks;
+  SSAPrunedLiveness directLiveness(function, &directDiscoverdBlocks);
+  directLiveness.initializeDef(getCurrentDef());
+  directLiveness.computeSimple();
+  OSSACompleteLifetime::visitAvailabilityBoundary(
+      getCurrentDef(), directLiveness, [&](auto *unreachable, auto end) {
+        if (end == OSSACompleteLifetime::LifetimeEnd::Boundary) {
+          recordUnreachableLifetimeEnd(unreachable);
+        }
+        unreachable->visitPriorInstructions([&](auto *inst) {
+          liveness->extendToNonUse(inst);
+          return true;
+        });
+      });
+}
+
+/// Extend liveness to the copy-extended availability boundary of currentDef.
+/// Prevents destroys from being inserted between borrows of (copies of) the
+/// def and dead-ends.
+///
+/// Example:
+///     %def need not be lexical
+///     %c = copy_value %def
+///     %sb = store_borrow %c to %addr
+///     // Must extend lifetime of %def up to this point.  Otherwise, a
+///     // destroy_value could be inserted within a borrow scope or interior
+///     // pointer use.
+///     unreachable
+void OSSACanonicalizeOwned::extendLivenessToDeadEnds() {
+  // TODO: OSSACompleteLifetime: Once lifetimes are always complete, delete
+  //                               this method.
+  SmallVector<SILBasicBlock *, 32> discoveredBlocks(this->discoveredBlocks);
+  SSAPrunedLiveness completeLiveness(*liveness, &discoveredBlocks);
+
+  for (auto destroy : destroys) {
+    if (liveness->isWithinBoundary(destroy, /*deadEndBlocks=*/nullptr))
+      continue;
+    completeLiveness.updateForUse(destroy, /*lifetimeEnding*/ true);
+  }
+
+  // Demote consuming uses within complete liveness to non-consuming uses.
+  //
+  // OSSACompleteLifetime considers the lifetime of a single value.  Such
+  // lifetimes never continue beyond consumes.
+  std::optional<llvm::SmallPtrSet<SILInstruction *, 8>> lastUsers;
+  auto isConsumeOnBoundary = [&](SILInstruction *instruction) -> bool {
+    if (!lastUsers) {
+      // Avoid computing lastUsers if possible.
+      auto *function = getCurrentDef()->getFunction();
+      auto *deadEnds = deadEndBlocksAnalysis->get(function);
+      llvm::SmallVector<SILBasicBlock *, 8> completeConsumingBlocks(
+          consumingBlocks.getArrayRef());
+      for (auto &block : *function) {
+        if (!deadEnds->isDeadEnd(&block))
+          continue;
+        completeConsumingBlocks.push_back(&block);
+      }
+      PrunedLivenessBoundary boundary;
+      liveness->computeBoundary(boundary, completeConsumingBlocks);
+
+      lastUsers.emplace();
+      for (auto *lastUser : boundary.lastUsers) {
+        lastUsers->insert(lastUser);
+      }
+    }
+    return lastUsers->contains(instruction);
+  };
+  for (auto pair : liveness->getAllUsers()) {
+    if (!pair.second.isEnding())
+      continue;
+    auto *instruction = pair.first;
+    if (isConsumeOnBoundary(instruction))
+      continue;
+    // Demote instruction's lifetime-ending-ness to non-lifetime-ending.
+    completeLiveness.updateForUse(pair.first, /*lifetimeEnding=*/false);
+  }
+
+  OSSACompleteLifetime::visitAvailabilityBoundary(
+      getCurrentDef(), completeLiveness, [&](auto *unreachable, auto end) {
+        if (end == OSSACompleteLifetime::LifetimeEnd::Boundary) {
+          recordUnreachableLifetimeEnd(unreachable);
+        }
+        unreachable->visitPriorInstructions([&](auto *inst) {
+          liveness->extendToNonUse(inst);
+          return true;
+        });
+      });
+}
+
+void OSSACanonicalizeOwned::extendLivenessToDeinitBarriers() {
+  SmallVector<SILInstruction *, 8> ends;
+  if (endingLifetimeAtExplicitEnds()) {
+    visitExtendedUnconsumedBoundary(
+        explicitLifetimeEnds, [&ends](auto *instruction, auto lifetimeEnding) {
+          instruction->visitSubsequentInstructions([&](auto *next) {
+            ends.push_back(next);
+            return true;
+          });
+        });
+  } else {
+    for (auto destroy : destroys) {
+      if (destroy->getOperand(0) != getCurrentDef())
+        continue;
+      ends.push_back(destroy);
+    }
+  }
+
+  auto *def = getCurrentDef()->getDefiningInstruction();
+  using InitialBlocks = ArrayRef<SILBasicBlock *>;
+  auto *defBlock = getCurrentDef()->getParentBlock();
+  auto initialBlocks = defBlock ? InitialBlocks(defBlock) : InitialBlocks();
+  ReachableBarriers barriers;
+  findBarriersBackward(
+      ends, initialBlocks, *getCurrentDef()->getFunction(), barriers,
+      [&](auto *inst) {
+        if (inst == def)
+          return true;
+        if (!isDeinitBarrier(inst, calleeAnalysis))
+          return false;
+        // For the most part, instructions that are deinit
+        // barriers in the abstract are also deinit barriers
+        // for the purposes of canonicalizing def's lifetime.
+        //
+        // There is an important exception: transferring an
+        // owned lexical lifetime into a callee.  If the
+        // instruction is a full apply which consumes def,
+        // then it isn't a deinit barrier.  Keep looking for
+        // barriers above it.
+        auto apply = FullApplySite::isa(inst);
+        if (!apply)
+          return true;
+        return liveness->isInterestingUser(inst) !=
+               PrunedLiveness::IsInterestingUser::LifetimeEndingUse;
+      });
+  for (auto *barrier : barriers.instructions) {
+    liveness->extendToNonUse(barrier);
+  }
+  for (auto *barrier : barriers.phis) {
+    for (auto *predecessor : barrier->getPredecessorBlocks()) {
+      liveness->extendToNonUse(predecessor->getTerminator());
+    }
+  }
+  for (auto *edge : barriers.edges) {
+    auto *predecessor = edge->getSinglePredecessorBlock();
+    assert(predecessor);
+    liveness->extendToNonUse(&predecessor->back());
+  }
+  // Ignore barriers.initialBlocks.  If the collection is non-empty, it
+  // contains the def-block.  Its presence means that no barriers were found
+  // between lifetime ends and def.  In that case, no new instructions need to
+  // be added to liveness.
+}
+
+// Return true if \p inst is an end_access whose access scope overlaps the end
+// of the pruned live range. This means that a hoisted destroy might execute
+// within the access scope which previously executed outside the access scope.
+//
+// Not overlapping (ignored):
+//
+//     %def
+//     use %def     // pruned liveness ends here
+//     begin_access // access scope unrelated to def
+//     end_access
+//
+// Overlapping (must extend pruned liveness):
+//
+//     %def
+//     begin_access // access scope unrelated to def
+//     use %def     // pruned liveness ends here
+//     end_access
+//
+// Overlapping (must extend pruned liveness):
+//
+//     begin_access // access scope unrelated to def
+//     %def
+//     use %def     // pruned liveness ends here
+//     end_access
+//
+bool OSSACanonicalizeOwned::endsAccessOverlappingPrunedBoundary(
+    SILInstruction *inst) {
+  if (isa<EndUnpairedAccessInst>(inst)) {
+    return true;
+  }
+  auto *endAccess = dyn_cast<EndAccessInst>(inst);
+  if (!endAccess) {
+    return false;
+  }
+  auto *beginAccess = endAccess->getBeginAccess();
+  SILBasicBlock *beginBB = beginAccess->getParent();
+  switch (liveness->getBlockLiveness(beginBB)) {
+  case PrunedLiveBlocks::LiveOut:
+    // Found partial overlap of the form:
+    //     currentDef
+    //     beginAccess
+    //     br...
+    //   bb...
+    //     use
+    //     endAccess
+    return true;
+  case PrunedLiveBlocks::LiveWithin:
+    // Check for partial overlap of this form where beginAccess and the last use
+    // are in the same block:
+    //     currentDef
+    //     beginAccess
+    //     use
+    //     endAccess
+    if (std::find_if(std::next(beginAccess->getIterator()), beginBB->end(),
+                     [this](SILInstruction &nextInst) {
+                       return liveness->isInterestingUser(&nextInst) !=
+                              PrunedLiveness::NonUser;
+                     }) != beginBB->end()) {
+      // An interesting use after the beginAccess means overlap.
+      return true;
+    }
+    return false;
+  case PrunedLiveBlocks::Dead:
+    // Check for partial overlap of this form where beginAccess and currentDef
+    // are in different blocks:
+    //     beginAccess
+    //     br...
+    //  bb...
+    //     currentDef
+    //     endAccess
+    //
+    // Since beginAccess is not within the canonical live range, its access
+    // scope overlaps only if there is a path from beginAccess to currentDef
+    // that does not pass through endAccess. endAccess is dominated by
+    // both currentDef and begin_access. Therefore, such a path only exists if
+    // beginAccess dominates currentDef.
+    return domTree->properlyDominates(beginAccess->getParent(),
+                                      getCurrentDef()->getParentBlock());
+  }
+  llvm_unreachable("covered switch");
+}
+
+// Find all overlapping access scopes and extend pruned liveness to cover them:
+//
+// This may also unnecessarily, but conservatively extend liveness over some
+// originally overlapping access, such as:
+//
+//     begin_access // access scope unrelated to def
+//     %def
+//     use %def
+//     destroy %def
+//     end_access
+//
+// Or:
+//
+//     %def
+//     begin_access // access scope unrelated to def
+//     use %def
+//     destroy %def
+//     end_access
+//
+// To minimize unnecessary lifetime extension, only search for end_access
+// within dead blocks that are backward reachable from an original destroy.
+//
+// Note that lifetime extension is iterative because adding a new liveness use
+// may create new overlapping access scopes. This can happen because there is no
+// guarantee of strict stack discipline across unrelated access. For example:
+//
+//     %def
+//     begin_access A
+//     use %def        // Initial pruned lifetime boundary
+//     begin_access B
+//     end_access A    // Lifetime boundary after first extension
+//     end_access B    // Lifetime boundary after second extension
+//     destroy %def
+//
+// If the lifetime extension did not iterate, then def would be destroyed within
+// B's access scope when originally it was destroyed outside that scope.
+void OSSACanonicalizeOwned::extendLivenessThroughOverlappingAccess() {
+  this->accessBlocks = accessBlockAnalysis->get(getCurrentDef()->getFunction());
+
+  // Visit each original consuming use or destroy as the starting point for a
+  // backward CFG traversal. This traversal must only visit blocks within the
+  // original extended lifetime.
+  bool changed = true;
+  while (changed) {
+    changed = false;
+    // The blocks in which we may have to extend liveness over access scopes.
+    //
+    // It must be populated first so that we can test membership during the loop
+    // (see findLastConsume).
+    BasicBlockSetVector blocksToVisit(getCurrentDef()->getFunction());
+    for (auto *block : consumingBlocks) {
+      blocksToVisit.insert(block);
+    }
+    for (auto iterator = blocksToVisit.begin(); iterator != blocksToVisit.end();
+         ++iterator) {
+      auto *bb = *iterator;
+      // If the block isn't dead, then we won't need to extend liveness within
+      // any of its predecessors (though we may within it).
+      if (liveness->getBlockLiveness(bb) != PrunedLiveBlocks::Dead)
+        continue;
+      // Continue searching upward to find the pruned liveness boundary.
+      for (auto *predBB : bb->getPredecessorBlocks()) {
+        blocksToVisit.insert(predBB);
+      }
+    }
+    for (auto *bb : blocksToVisit) {
+      auto blockLiveness = liveness->getBlockLiveness(bb);
+      // Ignore blocks within pruned liveness.
+      if (blockLiveness == PrunedLiveBlocks::LiveOut) {
+        continue;
+      }
+      if (blockLiveness == PrunedLiveBlocks::Dead) {
+        // Otherwise, ignore dead blocks with no nonlocal end_access.
+        if (!accessBlocks->containsNonLocalEndAccess(bb)) {
+          continue;
+        }
+      }
+      bool blockHasUse = (blockLiveness == PrunedLiveBlocks::LiveWithin);
+      // Find the latest partially overlapping access scope, if one exists:
+      //     use %def // pruned liveness ends here
+      //     end_access
+
+      // Whether to look for the last consume in the block.
+      //
+      // We need to avoid extending liveness over end_accesses that occur after
+      // original liveness ended.
+      bool findLastConsume =
+          consumingBlocks.contains(bb) &&
+          llvm::none_of(bb->getSuccessorBlocks(), [&](auto *successor) {
+            return blocksToVisit.contains(successor) &&
+                   liveness->getBlockLiveness(successor) ==
+                       PrunedLiveBlocks::Dead;
+          });
+      for (auto &inst : llvm::reverse(*bb)) {
+        if (findLastConsume) {
+          findLastConsume = !destroys.contains(&inst);
+          continue;
+        }
+        // Stop at the latest use. An earlier end_access does not overlap.
+        if (blockHasUse &&
+            liveness->isInterestingUser(&inst) != PrunedLiveness::NonUser) {
+          break;
+        }
+        if (endsAccessOverlappingPrunedBoundary(&inst)) {
+          liveness->extendToNonUse(&inst);
+          changed = true;
+          break;
+        }
+      }
+      // If liveness changed, might as well restart CFG traversal.
+      if (changed) {
+        break;
+      }
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// MARK: Step 2. Find the "original" (unextended) boundary determined by the
+//               liveness built up in step 1.
+//===----------------------------------------------------------------------===//
+
+void OSSACanonicalizeOwned::findOriginalBoundary(
+    PrunedLivenessBoundary &boundary) {
+  assert(boundary.lastUsers.size() == 0 && boundary.boundaryEdges.size() == 0 &&
+         boundary.deadDefs.size() == 0);
+  liveness->computeBoundary(boundary, consumingBlocks.getArrayRef());
+}
+
+//===----------------------------------------------------------------------===//
+// MARK: Step 3. (Optional) Maximize lifetimes.
+//===----------------------------------------------------------------------===//
+
+/// At -Onone, there are some conflicting goals:
+/// On the one hand: good debugging experience.
+/// (1) do not shorten value's lifetime
+/// On the other: demonstrate semantics.
+/// (2) consume value at same places it will be consumed at -O
+/// (3) ensure there are no more copies than there would be at -O
+///
+/// (2) and (3) are equivalent--extra (compared to -O) copies arise from failing
+/// to end lifetimes at consuming uses (which then need their own copies).
+///
+/// We achieve (2) and (3) always.  We achieve (1) where possible.
+///
+/// Conceptually, the strategy is the following:
+/// - Collect the blocks in which the value was live before canonicalization.
+///   These are the "original" live blocks (originalLiveBlocks).
+///   [Color these blocks green.]
+/// - From within that collection, collect the blocks which contain a _final_
+///   consuming, non-destroy use, and their iterative successors.
+///   These are the "consumed" blocks (consumedAtExitBlocks).
+///   [Color these blocks red.]
+/// - Extend liveness down to the boundary between originalLiveBlocks and
+///   consumedAtExitBlocks blocks.
+///   [Extend liveness down to the boundary between green blocks and red.]
+/// - In particular, in regions of originalLiveBlocks which have no boundary
+///   with consumedAtExitBlocks, liveness should be extended to its original
+///   extent.
+///   [Extend liveness down to the boundary between green blocks and uncolored.]
+void OSSACanonicalizeOwned::visitExtendedUnconsumedBoundary(
+    ArrayRef<SILInstruction *> consumes,
+    llvm::function_ref<void(SILInstruction *, PrunedLiveness::LifetimeEnding)>
+        visitor) {
+  auto currentDef = getCurrentDef();
+
+#ifndef NDEBUG
+  for (auto *consume : consumes) {
+    assert(!liveness->isWithinBoundary(consume, /*deadEndBlocks=*/nullptr));
+  }
+#endif
+
+  // First, collect the blocks that were _originally_ live.  We can't use
+  // liveness here because it doesn't include blocks that occur before a
+  // destroy_value.
+  BasicBlockSet originalLiveBlocks(currentDef->getFunction());
+  {
+    // Some of the work here was already done by computeCanonicalLiveness.
+    // Specifically, it already discovered all blocks containing (transitive)
+    // uses and blocks that appear between them and the def.
+    //
+    // Seed the set with what it already discovered.
+    for (auto *discoveredBlock : liveness->getDiscoveredBlocks())
+      originalLiveBlocks.insert(discoveredBlock);
+
+    // Start the walk from the consuming blocks (which includes destroys as well
+    // as the other consuming uses).
+    BasicBlockWorklist worklist(currentDef->getFunction());
+    for (auto *consumingBlock : consumingBlocks) {
+      worklist.push(consumingBlock);
+    }
+
+    // Walk backwards from consuming blocks.
+    while (auto *block = worklist.pop()) {
+      if (!originalLiveBlocks.insert(block))
+        continue;
+      for (auto *predecessor : block->getPredecessorBlocks()) {
+        // If the block was discovered by liveness, we already added it to the
+        // set.
+        if (originalLiveBlocks.contains(predecessor))
+          continue;
+        worklist.pushIfNotVisited(predecessor);
+      }
+    }
+  }
+
+  // Second, collect the blocks which contain a _final_ consuming use and their
+  // iterative successors within the originalLiveBlocks.
+  BasicBlockSet consumedAtExitBlocks(currentDef->getFunction());
+  // The subset of consumedAtExitBlocks which do not contain a _final_ consuming
+  // use, i.e. the subset that is dead.
+  StackList<SILBasicBlock *> consumedAtEntryBlocks(currentDef->getFunction());
+  {
+    // Start the forward walk from blocks which contain _final_ non-destroy
+    // consumes. These are just the instructions on the boundary which aren't
+    // destroys.
+    BasicBlockWorklist worklist(currentDef->getFunction());
+    for (auto *instruction : consumes) {
+      if (destroys.contains(instruction))
+        continue;
+      if (liveness->isInterestingUser(instruction) !=
+          PrunedLiveness::IsInterestingUser::LifetimeEndingUse)
+        continue;
+      worklist.push(instruction->getParent());
+    }
+    while (auto *block = worklist.pop()) {
+      consumedAtExitBlocks.insert(block);
+      for (auto *successor : block->getSuccessorBlocks()) {
+        if (!originalLiveBlocks.contains(successor))
+          continue;
+        worklist.pushIfNotVisited(successor);
+        consumedAtEntryBlocks.push_back(successor);
+      }
+    }
+  }
+
+  // Third, find the blocks on the boundary between the originalLiveBlocks
+  // blocks and the consumedAtEntryBlocks blocks.  Extend liveness "to the end"
+  // of these blocks.
+  for (auto *block : consumedAtEntryBlocks) {
+    for (auto *predecessor : block->getPredecessorBlocks()) {
+      if (consumedAtExitBlocks.contains(predecessor))
+        continue;
+      // Add "the instruction(s) before the terminator" of the predecessor to
+      // liveness.
+      predecessor->getTerminator()->visitPriorInstructions([&](auto *inst) {
+        visitor(inst, PrunedLiveness::LifetimeEnding::Value::NonUse);
+        return true;
+      });
+    }
+  }
+
+  // Finally, preserve the destroys which weren't in the consumed region in
+  // place: hoisting such destroys would not avoid copies.
+  for (auto *destroy : destroys) {
+    auto *block = destroy->getParent();
+    // If the destroy is in a consumed block or a final consuming block,
+    // hoisting it would avoid a copy.
+    if (consumedAtExitBlocks.contains(block))
+      continue;
+    visitor(destroy, PrunedLiveness::LifetimeEnding::Value::Ending);
+  }
+}
+
+void OSSACanonicalizeOwned::extendUnconsumedLiveness(
+    PrunedLivenessBoundary const &boundary) {
+  visitExtendedUnconsumedBoundary(
+      boundary.lastUsers, [&](auto *instruction, auto lifetimeEnding) {
+        liveness->updateForUse(instruction, lifetimeEnding);
+      });
+}
+
+//===----------------------------------------------------------------------===//
+// MARK: Step 4. Extend the "original" boundary from step 2 up to destroys that
+//               aren't separated from it by "interesting" instructions.
+//===----------------------------------------------------------------------===//
+
+namespace {
+/// Extends the boundary from PrunedLiveness down to preexisting destroys of the
+/// def which aren't separated from the original boundary by "interesting"
+/// instructions.
+///
+/// The motivation for extending the boundary is to avoid "churning" when
+/// iterating to a fixed point by canonicalizing the lifetimes of several
+/// values with overlapping live ranges and failing to find a fixed point
+/// because their destroys are repeatedly hoisted over one another.
+class ExtendBoundaryToDestroys final {
+  using InstructionPredicate = llvm::function_ref<bool(SILInstruction *)>;
+  SSAPrunedLiveness &liveness;
+  PrunedLivenessBoundary const &originalBoundary;
+  SILValue currentDef;
+  BasicBlockSet seenMergePoints;
+  InstructionPredicate isDestroy;
+
+public:
+  ExtendBoundaryToDestroys(SSAPrunedLiveness &liveness,
+                           PrunedLivenessBoundary const &originalBoundary,
+                           SILValue currentDef, InstructionPredicate isDestroy)
+      : liveness(liveness), originalBoundary(originalBoundary),
+        currentDef(currentDef), seenMergePoints(currentDef->getFunction()),
+        isDestroy(isDestroy){};
+  ExtendBoundaryToDestroys(ExtendBoundaryToDestroys const &) = delete;
+  ExtendBoundaryToDestroys &
+  operator=(ExtendBoundaryToDestroys const &) = delete;
+
+  /// Compute the extended boundary by walking out from the original boundary
+  /// (from PrunedLiveness::computeBoundary) down to any destroys that appear
+  /// later but which aren't separated from the original boundary by
+  /// "interesting" users.
+  void extend(PrunedLivenessBoundary &boundary) {
+    for (auto *def : originalBoundary.deadDefs) {
+      extendBoundaryFromDef(def, boundary);
+    }
+    for (auto *destination : originalBoundary.boundaryEdges) {
+      extendBoundaryFromBoundaryEdge(destination, boundary);
+    }
+    for (auto *user : originalBoundary.lastUsers) {
+      extendBoundaryFromUser(user, boundary);
+    }
+  }
+
+  /// Look past ignoreable instructions to find the _last_ destroy after the
+  /// specified instruction that destroys \p def.
+  static DestroyValueInst *findDestroyAfter(SILInstruction *previous,
+                                            SILValue def,
+                                            InstructionPredicate isDestroy) {
+    DestroyValueInst *retval = nullptr;
+    for (auto *instruction = previous->getNextInstruction(); instruction;
+         instruction = instruction->getNextInstruction()) {
+      if (!OSSACanonicalizeOwned::ignoredByDestroyHoisting(
+              instruction->getKind()))
+        break;
+      if (isDestroy(instruction))
+        retval = cast<DestroyValueInst>(instruction);
+    }
+    return retval;
+  }
+
+  /// Look past ignoreable instructions to find the _last_ destroy at or after
+  /// the specified instruction that destroys \p def.
+  static DestroyValueInst *
+  findDestroyAtOrAfter(SILInstruction *start, SILValue def,
+                       InstructionPredicate isDestroy) {
+    if (isDestroy(start))
+      return cast<DestroyValueInst>(start);
+    return findDestroyAfter(start, def, isDestroy);
+  }
+
+  /// Look past ignoreable instructions to find the _first_ destroy in \p
+  /// destination that destroys \p def and isn't separated from the beginning
+  /// by "interesting" instructions.
+  static DestroyValueInst *
+  findDestroyFromBlockBegin(SILBasicBlock *destination, SILValue def,
+                            InstructionPredicate isDestroy) {
+    return findDestroyAtOrAfter(&*destination->begin(), def, isDestroy);
+  }
+
+private:
+  /// Compute the points on the extended boundary found by walking forward from
+  /// the dead def (starting either with the top of the block in the case of a
+  /// dead arg or the next instruction in the case of an instruction) down to
+  /// any destroys that appear later but which aren't separated from the
+  /// original boundary by "interesting" users.
+  ///
+  /// If a destroy is found, it becomes a last user.  Otherwise, the boundary
+  /// stays in place and \p def remains a dead def.
+  void extendBoundaryFromDef(SILNode *def, PrunedLivenessBoundary &boundary) {
+    if (auto *arg = dyn_cast<SILArgument>(def)) {
+      if (auto *dvi = findDestroyFromBlockBegin(arg->getParent(), currentDef,
+                                                isDestroy)) {
+        boundary.lastUsers.push_back(dvi);
+        return;
+      }
+    } else {
+      if (auto *dvi = findDestroyAfter(cast<SILInstruction>(def), currentDef,
+                                       isDestroy)) {
+        boundary.lastUsers.push_back(dvi);
+        return;
+      }
+    }
+    boundary.deadDefs.push_back(def);
+  }
+
+  /// Compute the points on the extended boundary found by walking down from the
+  /// boundary edge in the original boundary (uniquely determined by the
+  /// specified destination edge) down to any destroys that appear later but
+  /// which aren't separated from the original boundary by "interesting" users.
+  ///
+  /// If a destroy is found, it becomes a last user.  Otherwise, the boundary
+  /// stays in place and \p destination remains a boundary edge.
+  void extendBoundaryFromBoundaryEdge(SILBasicBlock *destination,
+                                      PrunedLivenessBoundary &boundary) {
+    if (auto *dvi =
+            findDestroyFromBlockBegin(destination, currentDef, isDestroy)) {
+      boundary.lastUsers.push_back(dvi);
+    } else {
+      boundary.boundaryEdges.push_back(destination);
+    }
+  }
+
+  /// Compute the points on the extended boundary found by walking down from the
+  /// specified instruction in the original boundary down to any destroys that
+  /// appear later but which aren't separated from the original boundary by
+  /// "interesting" users.
+  ///
+  /// If the user is consuming, the boundary remains in place.
+  ///
+  /// If the user is a terminator, see extendBoundaryFromTerminator.
+  ///
+  /// If a destroy is found after the (non-consuming, non-terminator) \p user,
+  /// it becomes a last user.  Otherwise, the boundary stays in place and \p
+  /// user remains a last user.
+  void extendBoundaryFromUser(SILInstruction *user,
+                              PrunedLivenessBoundary &boundary) {
+    if (isDestroy(user)) {
+      auto *dvi = cast<DestroyValueInst>(user);
+      auto *existingDestroy = findDestroyAtOrAfter(dvi, currentDef, isDestroy);
+      assert(existingDestroy && "couldn't find a destroy at or after one!?");
+      boundary.lastUsers.push_back(existingDestroy);
+      return;
+    }
+    switch (liveness.isInterestingUser(user)) {
+    case PrunedLiveness::IsInterestingUser::LifetimeEndingUse:
+      // Even if we saw a destroy after this consuming use, we don't want to
+      // add it to the boundary.  We will rewrite copies so that this user is
+      // the final consuming user on this path.
+      boundary.lastUsers.push_back(user);
+      return;
+    case PrunedLiveness::IsInterestingUser::NonLifetimeEndingUse:
+    case PrunedLiveness::IsInterestingUser::NonUser:
+      if (auto *terminator = dyn_cast<TermInst>(user)) {
+        extendBoundaryFromTerminator(terminator, boundary);
+        return;
+      }
+      if (auto *existingDestroy =
+              findDestroyAfter(user, currentDef, isDestroy)) {
+        boundary.lastUsers.push_back(existingDestroy);
+        return;
+      }
+      boundary.lastUsers.push_back(user);
+    }
+  }
+
+  /// Compute the points on the extended boundary by walking into \p user's
+  /// parent's successors and looking for destroys.
+  ///
+  /// If any destroys are found, they become last users and all other successors
+  /// (which lack destroys) become boundary edges.  If no destroys are found,
+  /// the boundary stays in place and \p user remains a last user.
+  void extendBoundaryFromTerminator(TermInst *user,
+                                    PrunedLivenessBoundary &boundary) {
+    auto *block = user->getParent();
+    // Record the successors at the beginning of which we didn't find destroys.
+    // If we found a destroy at the beginning of any other successor, then all
+    // the other edges become boundary edges.
+    SmallVector<SILBasicBlock *, 4> successorsWithoutDestroys;
+    bool foundDestroy = false;
+    for (auto *successor : block->getSuccessorBlocks()) {
+      // If multiple terminators were live and had the same successor, only
+      // record the boundary corresponding to that destination block once.
+      if (!seenMergePoints.insert(successor)) {
+        // Thanks to the lack of critical edges, having seen this successor
+        // before means it has multiple predecessors, so this must be \p block's
+        // unique successor.
+        assert(block->getSingleSuccessorBlock() == successor);
+        // When this merge point was encountered the first time, a
+        // destroy_value was sought from its top.  If one was found, it was
+        // added to the boundary. If no destroy_value was found, _that_ user
+        // (i.e. the one on behalf of which extendBoundaryFromTerminator was
+        // called which inserted successor into seenMergePoints) was added to
+        // the boundary.
+        //
+        // This time, if a destroy was found, it's already in the boundary.  If
+        // no destroy was found, though, _this_ user must be added to the
+        // boundary.
+        foundDestroy =
+            findDestroyFromBlockBegin(successor, currentDef, isDestroy);
+        continue;
+      }
+      if (auto *dvi =
+              findDestroyFromBlockBegin(successor, currentDef, isDestroy)) {
+        boundary.lastUsers.push_back(dvi);
+        foundDestroy = true;
+      } else {
+        successorsWithoutDestroys.push_back(successor);
+      }
+    }
+    if (foundDestroy) {
+      // If we found a destroy in any successor, then every block at the
+      // beginning of which we didn't find a destroy becomes a boundary edge.
+      for (auto *successor : successorsWithoutDestroys) {
+        boundary.boundaryEdges.push_back(successor);
+      }
+    } else {
+      boundary.lastUsers.push_back(user);
+    }
+  }
+};
+} // anonymous namespace
+
+void OSSACanonicalizeOwned::findExtendedBoundary(
+    PrunedLivenessBoundary const &originalBoundary,
+    PrunedLivenessBoundary &boundary) {
+  assert(boundary.lastUsers.size() == 0 && boundary.boundaryEdges.size() == 0 &&
+         boundary.deadDefs.size() == 0);
+  auto isDestroy = [&](auto *inst) { return destroys.contains(inst); };
+  ExtendBoundaryToDestroys extender(*liveness, originalBoundary,
+                                    getCurrentDef(), isDestroy);
+  extender.extend(boundary);
+}
+
+//===----------------------------------------------------------------------===//
+// MARK: Step 5. Insert destroys onto the boundary found in step 3 where needed.
+//===----------------------------------------------------------------------===//
+
+/// Create a new destroy_value instruction before the specified instruction and
+/// record it as a final consume.
+static void
+insertDestroyBeforeInstruction(SILInstruction *nextInstruction,
+                               SILValue currentDef, IsDeadEnd_t isDeadEnd,
+                               CanonicalOSSAConsumeInfo &consumes,
+                               SmallVectorImpl<DestroyValueInst *> &destroys,
+                               InstModCallbacks &callbacks) {
+  // OSSACompleteLifetime: This conditional clause can be deleted with
+  // complete lifetimes.
+  if (consumes.isUnreachableLifetimeEnd(nextInstruction)) {
+    // Don't create a destroy_value if the next instruction is an unreachable
+    // (or a terminator on the availability boundary of the dead-end region
+    // starting from the non-lifetime-ending boundary of `currentDef`).
+    //
+    // If there was a destroy here already, it would be reused.  Avoids
+    // creating an explicit destroy of a value which might have an unclosed
+    // borrow scope.  Doing so would result in
+    //
+    //     somewhere:
+    //       %def
+    //       %borrow = begin_borrow ...
+    //
+    //     die:
+    //       destroy_value %def
+    //       unreachable
+    //
+    // which is invalid (although the verifier doesn't catch
+    // it--rdar://115850528) because there must be an `end_borrow %borrow`
+    // before the destroy_value.
+    return;
+  }
+  SILBuilderWithScope builder(nextInstruction);
+  auto loc =
+      RegularLocation::getAutoGeneratedLocation(nextInstruction->getLoc());
+  auto *dvi =
+      builder.createDestroyValue(loc, currentDef, DontPoisonRefs, isDeadEnd);
+  callbacks.createdNewInst(dvi);
+  consumes.recordFinalConsume(dvi);
+  ++NumDestroysGenerated;
+  destroys.push_back(dvi);
+}
+
+/// Whether a destroy created at \p inst should be marked [dead_end].
+///
+/// It should be if
+/// (1) \p inst is itself in a dead-end region
+/// (2) all destroys after \p inst are [dead_end]
+static IsDeadEnd_t
+isDeadEndDestroy(SILInstruction *inst,
+                 SmallPtrSetVector<SILInstruction *, 8> const &destroys,
+                 BasicBlockSet &semanticDestroysBlocks,
+                 DeadEndBlocks *deadEnds) {
+  auto *parent = inst->getParent();
+  if (!deadEnds->isDeadEnd(parent)) {
+    // Only destroys in dead-ends can be non-meaningful (aka "dead end").
+    return IsntDeadEnd;
+  }
+  if (semanticDestroysBlocks.contains(parent)) {
+    // `parent` has a semantic destroy somewhere.  Is it after `inst`?
+    for (auto *i = inst; i; i = i->getNextInstruction()) {
+      if (!destroys.contains(i)) {
+        continue;
+      }
+      auto *dvi = cast<DestroyValueInst>(i);
+      if (!dvi->isDeadEnd()) {
+        // Some subsequent destroy within `parent` was meaningful, so one
+        // created at `inst` must be too.
+        return IsntDeadEnd;
+      }
+    }
+  }
+  // Walk the portion of the dead-end region after `parent` to check that all
+  // destroys are non-meaningful.
+  BasicBlockWorklist worklist(inst->getFunction());
+  for (auto *successor : parent->getSuccessorBlocks()) {
+    worklist.push(successor);
+  }
+  while (auto *block = worklist.pop()) {
+    assert(deadEnds->isDeadEnd(block));
+    if (semanticDestroysBlocks.contains(block)) {
+      // Some subsequent destroy was meaningful, so one created at `inst`
+      // must be too.
+      return IsntDeadEnd;
+    }
+    for (auto *successor : block->getSuccessorBlocks()) {
+      worklist.pushIfNotVisited(successor);
+    }
+  }
+  return IsDeadEnd;
+}
+
+/// Inserts destroys along the boundary where needed and records all final
+/// consuming uses.
+///
+/// Observations:
+/// - currentDef must be postdominated by some subset of its
+///   consuming uses, including destroys on all return paths.
+/// - The postdominating consumes cannot be within nested loops.
+/// - Any blocks in nested loops are now marked LiveOut.
+void OSSACanonicalizeOwned::insertDestroysOnBoundary(
+    PrunedLivenessBoundary const &boundary,
+    SmallVectorImpl<DestroyValueInst *> &newDestroys) {
+  BasicBlockSet semanticDestroyBlocks(getCurrentDef()->getFunction());
+  for (auto *destroy : destroys) {
+    if (!cast<DestroyValueInst>(destroy)->isDeadEnd()) {
+      semanticDestroyBlocks.insert(destroy->getParent());
+    }
+  }
+  auto isDeadEnd = [&semanticDestroyBlocks,
+                    this](SILInstruction *inst) -> IsDeadEnd_t {
+    return isDeadEndDestroy(
+        inst, destroys, semanticDestroyBlocks,
+        deadEndBlocksAnalysis->get(getCurrentDef()->getFunction()));
+  };
+  BasicBlockSet seenMergePoints(getCurrentDef()->getFunction());
+  for (auto *instruction : boundary.lastUsers) {
+    if (destroys.contains(instruction)) {
+      consumes.recordFinalConsume(instruction);
+      continue;
+    }
+    switch (liveness->isInterestingUser(instruction)) {
+    case PrunedLiveness::IsInterestingUser::LifetimeEndingUse:
+      consumes.recordFinalConsume(instruction);
+      continue;
+    case PrunedLiveness::IsInterestingUser::NonLifetimeEndingUse:
+    case PrunedLiveness::IsInterestingUser::NonUser:
+      if (isa<TermInst>(instruction)) {
+        auto *block = instruction->getParent();
+        for (auto *successor : block->getSuccessorBlocks()) {
+          if (!seenMergePoints.insert(successor)) {
+            assert(block->getSingleSuccessorBlock() == successor);
+            continue;
+          }
+          auto *insertionPoint = &*successor->begin();
+          insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
+                                         isDeadEnd(insertionPoint), consumes,
+                                         newDestroys, getCallbacks());
+          LLVM_DEBUG(llvm::dbgs() << "  Destroy after terminator "
+                                  << *instruction << " at beginning of ";
+                     successor->printID(llvm::dbgs(), false);
+                     llvm::dbgs() << "\n";);
+        }
+        continue;
+      }
+      auto *insertionPoint = instruction->getNextInstruction();
+      insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
+                                     isDeadEnd(insertionPoint), consumes,
+                                     newDestroys, getCallbacks());
+      LLVM_DEBUG(llvm::dbgs()
+                 << "  Destroy at last use " << insertionPoint << "\n");
+      continue;
+    }
+  }
+  for (auto *edgeDestination : boundary.boundaryEdges) {
+    auto *insertionPoint = &*edgeDestination->begin();
+    insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
+                                   isDeadEnd(insertionPoint), consumes,
+                                   newDestroys, getCallbacks());
+    LLVM_DEBUG(llvm::dbgs() << "  Destroy on edge " << edgeDestination << "\n");
+  }
+  for (auto *def : boundary.deadDefs) {
+    if (auto *arg = dyn_cast<SILArgument>(def)) {
+      auto *insertionPoint = &*arg->getParent()->begin();
+      insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
+                                     isDeadEnd(insertionPoint), consumes,
+                                     newDestroys, getCallbacks());
+      LLVM_DEBUG(llvm::dbgs()
+                 << "  Destroy after dead def arg " << arg << "\n");
+    } else {
+      auto *instruction = cast<SILInstruction>(def);
+      auto *insertionPoint = instruction->getNextInstruction();
+      assert(insertionPoint && "def instruction was a terminator?!");
+      insertDestroyBeforeInstruction(insertionPoint, getCurrentDef(),
+                                     isDeadEnd(insertionPoint), consumes,
+                                     newDestroys, getCallbacks());
+      LLVM_DEBUG(llvm::dbgs()
+                 << "  Destroy after dead def inst " << instruction << "\n");
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// MARK: Step 6. Rewrite copies and destroys
+//===----------------------------------------------------------------------===//
+
+/// The lifetime extends beyond given consuming use. Copy the value.
+///
+/// This can set the operand value, but cannot invalidate the use iterator.
+void swift::copyLiveUse(Operand *use, InstModCallbacks &instModCallbacks) {
+  SILInstruction *user = use->getUser();
+  SILBuilderWithScope builder(user->getIterator());
+
+  auto loc = RegularLocation::getAutoGeneratedLocation(user->getLoc());
+  auto *copy = builder.createCopyValue(loc, use->get());
+  instModCallbacks.createdNewInst(copy);
+  use->set(copy);
+
+  ++NumCopiesGenerated;
+  LLVM_DEBUG(llvm::dbgs() << "  Copying at last use " << *copy);
+}
+
+/// Revisit the def-use chain of currentDef. Mark unneeded original
+/// copies and destroys for deletion. Insert new copies for interior uses that
+/// require ownership of the used operand.
+void OSSACanonicalizeOwned::rewriteCopies(
+    SmallVectorImpl<DestroyValueInst *> const &newDestroys) {
+  assert(getCurrentDef()->getOwnershipKind() == OwnershipKind::Owned);
+
+  // Shadow discoveredDefs in order to constrain its uses.
+  const auto &discoveredDefs = this->discoveredDefs;
+
+  InstructionSetVector instsToDelete(getCurrentDef()->getFunction());
+
+  // Visit each operand in the def-use chain.
+  //
+  // Return true if the operand can use the current definition. Return false if
+  // it requires a copy.
+  auto visitUse = [&](Operand *use) {
+    auto *user = use->getUser();
+    if (destroys.contains(user)) {
+      auto *destroy = cast<DestroyValueInst>(user);
+      // If this destroy was marked as a final destroy, ignore it; otherwise,
+      // delete it.
+      if (!consumes.claimConsume(destroy)) {
+        instsToDelete.insert(destroy);
+        LLVM_DEBUG(llvm::dbgs() << "  Removing " << *destroy);
+        ++NumDestroysEliminated;
+      } else if (pruneDebugMode) {
+        // If this destroy was marked as a final destroy, add it to liveness so
+        // that we don't delete any debug instructions that occur before it.
+        // (Only relevant in pruneDebugMode).
+        liveness->updateForUse(destroy, /*lifetimeEnding*/ true);
+      }
+      return true;
+    }
+
+    // Nonconsuming uses do not need copies and cannot be marked as destroys.
+    // A lifetime-ending use here must be a consume because EndBorrow/Reborrow
+    // uses have been filtered out.
+    if (!use->isLifetimeEnding())
+      return true;
+
+    // If this use was not marked as a final destroy *or* this is not the first
+    // consumed operand we visited, then it needs a copy.
+    if (!consumes.claimConsume(user)) {
+      return false;
+    }
+
+    return true;
+  };
+
+  // Perform a def-use traversal, visiting each use operand.
+  for (auto def : discoveredDefs) {
+    switch (def.kind) {
+    case Def::BorrowedFrom:
+    case Def::Reborrow:
+      // Direct uses of these defs never need to be rewritten.  Being guaranteed
+      // values, none of their direct uses consume an owned value.
+      assert(def.value->getOwnershipKind() == OwnershipKind::Guaranteed);
+      break;
+    case Def::Root: {
+      SILValue value = def.value;
+      for (auto useIter = value->use_begin(), endIter = value->use_end();
+           useIter != endIter;) {
+        Operand *use = *useIter++;
+        if (!visitUse(use)) {
+          copyLiveUse(use, getCallbacks());
+        }
+      }
+      break;
+    }
+    case Def::Copy: {
+      SILValue value = def.value;
+      CopyValueInst *srcCopy = cast<CopyValueInst>(value);
+      // Recurse through copies while replacing their uses.
+      Operand *reusedCopyOp = nullptr;
+      for (auto useIter = srcCopy->use_begin();
+           useIter != srcCopy->use_end();) {
+        Operand *use = *useIter++;
+        if (!visitUse(use)) {
+          if (!reusedCopyOp && srcCopy->getParent() == use->getParentBlock()) {
+            reusedCopyOp = use;
+          } else {
+            copyLiveUse(use, getCallbacks());
+          }
+        }
+      }
+      if (!(reusedCopyOp && srcCopy->hasOneUse())) {
+        getCallbacks().replaceValueUsesWith(srcCopy, srcCopy->getOperand());
+        if (reusedCopyOp) {
+          reusedCopyOp->set(srcCopy);
+        } else {
+          if (instsToDelete.insert(srcCopy)) {
+            LLVM_DEBUG(llvm::dbgs() << "  Removing " << *srcCopy);
+            ++NumCopiesAndMovesEliminated;
+          }
+        }
+      }
+      break;
+    }
+    }
+  }
+  assert(!consumes.hasUnclaimedConsumes());
+
+  if (pruneDebugMode) {
+    for (auto *destroy : newDestroys) {
+      liveness->updateForUse(destroy, /*lifetimeEnding=*/true);
+    }
+    for (auto *dvi : debugValues) {
+      if (liveness->isWithinBoundary(
+              dvi,
+              deadEndBlocksAnalysis->get(getCurrentDef()->getFunction()))) {
+        continue;
+      }
+      LLVM_DEBUG(llvm::dbgs() << "  Removing debug_value: " << *dvi);
+      deleter.forceDelete(dvi);
+    }
+  }
+
+  // Remove the leftover copy_value and destroy_value instructions.
+  for (auto *inst : instsToDelete) {
+    deleter.forceDelete(inst);
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//                            MARK: Top-Level API
+//===----------------------------------------------------------------------===//
+
+bool OSSACanonicalizeOwned::computeLiveness() {
+  LLVM_DEBUG(llvm::dbgs() << "  Canonicalizing: " << currentDef);
+
+  if (currentDef->getOwnershipKind() != OwnershipKind::Owned) {
+    LLVM_DEBUG(llvm::dbgs() << "  not owned, never mind\n");
+    return false;
+  }
+
+  // Note: There is no need to register callbacks with this utility. 'onDelete'
+  // is the only one in use to handle dangling pointers, which could be done
+  // instead be registering a temporary handler with the pass. Canonicalization
+  // is only allowed to create and delete instructions that are associated with
+  // this canonical def (copies and destroys). Each canonical def has a disjoint
+  // extended lifetime. Any pass calling this utility should work at the level
+  // canonical defs, not individual instructions.
+  //
+  // NotifyWillBeDeleted will not work because copy rewriting removes operands
+  // before deleting instructions. Also prohibit setUse callbacks just because
+  // that would simply be unsound.
+  assert(!getCallbacks().notifyWillBeDeletedFunc &&
+         !getCallbacks().setUseValueFunc && "unsupported");
+
+  // Step 1: compute liveness
+  if (!computeCanonicalLiveness()) {
+    LLVM_DEBUG(llvm::dbgs() << "Failed to compute canonical liveness?!\n");
+    clear();
+    return false;
+  }
+  if (respectsDeadEnds() && hasAnyDeadEnds()) {
+    if (respectsDeinitBarriers()) {
+      extendLexicalLivenessToDeadEnds();
+    }
+    extendLivenessToDeadEnds();
+  }
+  if (respectsDeinitBarriers()) {
+    extendLivenessToDeinitBarriers();
+  }
+  if (accessBlockAnalysis) {
+    extendLivenessThroughOverlappingAccess();
+  }
+  return true;
+}
+
+void OSSACanonicalizeOwned::rewriteLifetimes() {
+  // Step 2: compute original boundary
+  PrunedLivenessBoundary originalBoundary;
+  findOriginalBoundary(originalBoundary);
+  PrunedLivenessBoundary extendedBoundary;
+  if (maximizeLifetime) {
+    // Step 3. (optional) maximize lifetimes
+    extendUnconsumedLiveness(originalBoundary);
+    originalBoundary.clear();
+    // Step 2: (again) recompute the original boundary since we've extended
+    //         liveness
+    findOriginalBoundary(originalBoundary);
+    // Step 4: extend boundary to destroys
+    findExtendedBoundary(originalBoundary, extendedBoundary);
+  } else {
+    // Step 3: (skipped)
+    // Step 4: extend boundary to destroys
+    findExtendedBoundary(originalBoundary, extendedBoundary);
+  }
+
+  SmallVector<DestroyValueInst *> newDestroys;
+  // Step 5: insert destroys and record consumes
+  insertDestroysOnBoundary(extendedBoundary, newDestroys);
+  // Step 6: rewrite copies and delete extra destroys
+  rewriteCopies(newDestroys);
+
+  clear();
+}
+
+/// Canonicalize a single extended owned lifetime.
+bool OSSACanonicalizeOwned::canonicalizeValueLifetime(
+    SILValue def, ArrayRef<SILInstruction *> lexicalLifetimeEnds) {
+  LivenessState livenessState(*this, def, lexicalLifetimeEnds);
+
+  // Don't canonicalize the lifetimes of values of move-only type.  According to
+  // language rules, they are fixed.
+  if (def->getType().isMoveOnly()) {
+    return false;
+  }
+
+  // Step 1: Compute liveness.
+  if (!computeLiveness()) {
+    LLVM_DEBUG(llvm::dbgs() << "Failed to compute liveness boundary!\n");
+    return false;
+  }
+
+  // Steps 2-6. \see rewriteUses for explanation of steps 2-6.
+  rewriteLifetimes();
+
+  return true;
+}
+
+namespace swift::test {
+// Arguments:
+// - bool: pruneDebug
+// - bool: maximizeLifetimes
+// - bool: "respectAccessScopes", whether to contract lifetimes to end within
+//         access scopes which they previously enclosed but can't be hoisted
+//         before
+// - SILValue: value to canonicalize
+// - [SILInstruction]: the lexicalLifetimeEnds to recognize
+// Dumps:
+// - function after value canonicalization
+static FunctionTest OSSACanonicalizeOwnedTest(
+    "ossa_canonicalize_lifetime",
+    [](auto &function, auto &arguments, auto &test) {
+      auto *accessBlockAnalysis =
+          test.template getAnalysis<NonLocalAccessBlockAnalysis>();
+      auto *deadEndBlocksAnalysis =
+          test.template getAnalysis<DeadEndBlocksAnalysis>();
+      auto *dominanceAnalysis = test.template getAnalysis<DominanceAnalysis>();
+      DominanceInfo *domTree = dominanceAnalysis->get(&function);
+      auto *calleeAnalysis = test.template getAnalysis<BasicCalleeAnalysis>();
+      auto pruneDebug = PruneDebugInsts_t(arguments.takeBool());
+      auto maximizeLifetimes = MaximizeLifetime_t(arguments.takeBool());
+      auto respectAccessScopes = arguments.takeBool();
+      InstructionDeleter deleter;
+      OSSACanonicalizeOwned canonicalizer(
+          pruneDebug, maximizeLifetimes, &function,
+          respectAccessScopes ? accessBlockAnalysis : nullptr,
+          deadEndBlocksAnalysis, domTree, calleeAnalysis, deleter);
+      auto value = arguments.takeValue();
+      SmallVector<SILInstruction *, 4> lexicalLifetimeEnds;
+      while (arguments.hasUntaken()) {
+        lexicalLifetimeEnds.push_back(arguments.takeInstruction());
+      }
+      canonicalizer.canonicalizeValueLifetime(value, lexicalLifetimeEnds);
+      function.print(llvm::outs());
+    });
+} // end namespace swift::test
+
+//===----------------------------------------------------------------------===//
+//                              MARK: Debugging
+//===----------------------------------------------------------------------===//
+
+SWIFT_ASSERT_ONLY_DECL(void CanonicalOSSAConsumeInfo::dump() const {
+  llvm::dbgs() << "Consumes:";
+  for (auto &blockAndInst : finalBlockConsumes) {
+    llvm::dbgs() << "  " << *blockAndInst.getSecond();
+  }
+})
diff --git a/lib/SILOptimizer/Utils/OptimizerBridging.cpp b/lib/SILOptimizer/Utils/OptimizerBridging.cpp
index d82274eec3e99..a1bafbf8c65e2 100644
--- a/lib/SILOptimizer/Utils/OptimizerBridging.cpp
+++ b/lib/SILOptimizer/Utils/OptimizerBridging.cpp
@@ -11,7 +11,14 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/SILOptimizer/OptimizerBridging.h"
+#include "../../IRGen/IRGenModule.h"
+#include "swift/AST/SemanticAttrs.h"
+#include "swift/SIL/DynamicCasts.h"
+#include "swift/SIL/OSSACompleteLifetime.h"
+#include "swift/SIL/SILCloner.h"
+#include "swift/SIL/Test.h"
 #include "swift/SILOptimizer/Analysis/Analysis.h"
+#include "swift/SILOptimizer/IPO/ClosureSpecializer.h"
 #include "swift/SILOptimizer/Utils/CFGOptUtils.h"
 #include "swift/SILOptimizer/Utils/ConstantFolding.h"
 #include "swift/SILOptimizer/Utils/Devirtualize.h"
@@ -21,11 +28,6 @@
 #include "swift/SILOptimizer/Utils/SILOptFunctionBuilder.h"
 #include "swift/SILOptimizer/Utils/SpecializationMangler.h"
 #include "swift/SILOptimizer/Utils/StackNesting.h"
-#include "swift/SILOptimizer/IPO/ClosureSpecializer.h"
-#include "swift/SIL/DynamicCasts.h"
-#include "swift/SIL/OSSALifetimeCompletion.h"
-#include "swift/SIL/SILCloner.h"
-#include "../../IRGen/IRGenModule.h"
 
 using namespace swift;
 
@@ -47,24 +49,19 @@ llvm::cl::opt<bool> DisableSwiftVerification(
 //                              PassManager
 //===----------------------------------------------------------------------===//
 
-static BridgedUtilities::VerifyFunctionFn verifyFunctionFunction;
-
-void BridgedUtilities::registerVerifier(VerifyFunctionFn verifyFunctionFn) {
-  verifyFunctionFunction = verifyFunctionFn;
-}
-
 void SILPassManager::runSwiftFunctionVerification(SILFunction *f) {
-  if (!verifyFunctionFunction)
-    return;
-
   if (f->getModule().getOptions().VerifyNone)
     return;
 
   if (DisableSwiftVerification)
     return;
 
+  if (f->hasSemanticsAttr(semantics::NO_SIL_VERIFICATION)) {
+    return;
+  }
+
   getSwiftPassInvocation()->beginVerifyFunction(f);
-  verifyFunctionFunction({getSwiftPassInvocation()}, {f});
+  BridgedVerifier::runSwiftFunctionVerification(f, getSwiftPassInvocation());
   getSwiftPassInvocation()->endVerifyFunction();
 }
 
@@ -79,34 +76,6 @@ void SILPassManager::runSwiftModuleVerification() {
 //                           OptimizerBridging
 //===----------------------------------------------------------------------===//
 
-void BridgedChangeNotificationHandler::notifyChanges(Kind changeKind) const {
-  switch (changeKind) {
-  case Kind::instructionsChanged:
-    invocation->notifyChanges(SILAnalysis::InvalidationKind::Instructions);
-    break;
-  case Kind::callsChanged:
-    invocation->notifyChanges(SILAnalysis::InvalidationKind::CallsAndInstructions);
-    break;
-  case Kind::branchesChanged:
-    invocation->notifyChanges(SILAnalysis::InvalidationKind::BranchesAndInstructions);
-    break;
-  case Kind::effectsChanged:
-    invocation->notifyChanges(SILAnalysis::InvalidationKind::Effects);
-    break;
-  case Kind::functionTablesChanged:
-    invocation->notifyFunctionTablesChanged();
-    break;
-  }
-}
-
-BridgedOwnedString BridgedPassContext::getModuleDescription() const {
-  std::string str;
-  llvm::raw_string_ostream os(str);
-  invocation->getPassManager()->getModule()->print(os);
-  str.pop_back(); // Remove trailing newline.
-  return BridgedOwnedString(str);
-}
-
 bool BridgedPassContext::tryOptimizeApplyOfPartialApply(BridgedInstruction closure) const {
   auto *pa = closure.getAs<PartialApplyInst>();
   SILBuilder builder(pa);
@@ -151,6 +120,11 @@ void BridgedPassContext::inlineFunction(BridgedInstruction apply, bool mandatory
                               funcBuilder, deleter);
 }
 
+void BridgedPassContext::eraseFunction(BridgedFunction function) const {
+  invocation->getPassManager()->notifyWillDeleteFunction(function.getFunction());
+  invocation->getPassManager()->getModule()->eraseFunction(function.getFunction());
+}
+
 static const irgen::TypeInfo &getTypeInfoOfBuiltin(swift::SILType type, irgen::IRGenModule &IGM) {
   SILType lowered = IGM.getLoweredType(swift::Lowering::AbstractionPattern::getOpaque(), type.getASTType());
   return IGM.getTypeInfo(lowered);
@@ -199,14 +173,16 @@ bool BridgedPassContext::canMakeStaticObjectReadOnly(BridgedType type) const {
 }
 
 OptionalBridgedFunction BridgedPassContext::specializeFunction(BridgedFunction function,
-                                                               BridgedSubstitutionMap substitutions) const {
+                                                               BridgedSubstitutionMap substitutions,
+                                                               bool convertIndirectToDirect,
+                                                               bool isMandatory) const {
   swift::SILModule *mod = invocation->getPassManager()->getModule();
   SILFunction *origFunc = function.getFunction();
   SubstitutionMap subs = substitutions.unbridged();
   ReabstractionInfo ReInfo(mod->getSwiftModule(), mod->isWholeModule(),
-                           ApplySite(), origFunc, subs, IsNotSerialized,
-                           /*ConvertIndirectToDirect=*/true,
-                           /*dropMetatypeArgs=*/false);
+                           ApplySite(), origFunc, subs, origFunc->getSerializedKind(),
+                           convertIndirectToDirect,
+                           /*dropUnusedArguments=*/false);
 
   if (!ReInfo.canBeSpecialized()) {
     return {nullptr};
@@ -214,8 +190,8 @@ OptionalBridgedFunction BridgedPassContext::specializeFunction(BridgedFunction f
 
   SILOptFunctionBuilder FunctionBuilder(*invocation->getTransform());
 
-  GenericFuncSpecializer FuncSpecializer(FunctionBuilder, origFunc, subs,
-                                         ReInfo, /*isMandatory=*/true);
+  GenericFuncSpecializer FuncSpecializer(FunctionBuilder, origFunc, ReInfo.getClonerParamSubstitutionMap(),
+                                         ReInfo, isMandatory);
   SILFunction *SpecializedF = FuncSpecializer.lookupSpecialization();
   if (!SpecializedF) SpecializedF = FuncSpecializer.tryCreateSpecialization();
   if (!SpecializedF || SpecializedF->getLoweredFunctionType()->hasError()) {
@@ -285,61 +261,76 @@ BridgedOwnedString BridgedPassContext::mangleAsyncRemoved(BridgedFunction functi
   return BridgedOwnedString(Mangler.mangle());
 }
 
-BridgedOwnedString BridgedPassContext::mangleWithDeadArgs(const SwiftInt * _Nullable deadArgs,
-                                                          SwiftInt numDeadArgs,
+BridgedOwnedString BridgedPassContext::mangleWithDeadArgs(BridgedArrayRef bridgedDeadArgIndices,
                                                           BridgedFunction function) const {
   SILFunction *f = function.getFunction();
   Mangle::FunctionSignatureSpecializationMangler Mangler(f->getASTContext(),
       Demangle::SpecializationPass::FunctionSignatureOpts,
       f->getSerializedKind(), f);
-  for (SwiftInt idx = 0; idx < numDeadArgs; idx++) {
+  for (SwiftInt idx : bridgedDeadArgIndices.unbridged<SwiftInt>()) {
     Mangler.setArgumentDead((unsigned)idx);
   }
   return BridgedOwnedString(Mangler.mangle());
 }
 
 BridgedOwnedString BridgedPassContext::mangleWithClosureArgs(
-  BridgedValueArray bridgedClosureArgs,
-  BridgedArrayRef bridgedClosureArgIndices,
-  BridgedFunction applySiteCallee
+  BridgedArrayRef closureArgManglings, BridgedFunction applySiteCallee
 ) const {
   auto pass = Demangle::SpecializationPass::ClosureSpecializer;
   auto serializedKind = applySiteCallee.getFunction()->getSerializedKind();
   Mangle::FunctionSignatureSpecializationMangler mangler(applySiteCallee.getFunction()->getASTContext(),
       pass, serializedKind, applySiteCallee.getFunction());
 
-  llvm::SmallVector<swift::SILValue, 16> closureArgsStorage;
-  auto closureArgs = bridgedClosureArgs.getValues(closureArgsStorage);
-  auto closureArgIndices = bridgedClosureArgIndices.unbridged<SwiftInt>();
-
-  assert(closureArgs.size() == closureArgIndices.size() &&
-         "Number of closures arguments and number of closure indices do not match!");
+  auto closureArgs = closureArgManglings.unbridged<ClosureArgMangling>();
 
-  for (size_t i = 0; i < closureArgs.size(); i++) {
-    auto closureArg = closureArgs[i];
-    auto closureArgIndex = closureArgIndices[i];
-
-    if (auto *PAI = dyn_cast<PartialApplyInst>(closureArg)) {
-      mangler.setArgumentClosureProp(closureArgIndex,
-                                     const_cast<PartialApplyInst *>(PAI));
+  for (ClosureArgMangling argElmt : closureArgs) {
+    auto closureArgIndex = (unsigned)argElmt.argIdx;
+    if (SILInstruction *inst = argElmt.inst.unbridged()) {
+      mangler.setArgumentClosureProp(closureArgIndex, inst);
     } else {
-      auto *TTTFI = cast<ThinToThickFunctionInst>(closureArg);
-      mangler.setArgumentClosureProp(closureArgIndex, 
-                                     const_cast<ThinToThickFunctionInst *>(TTTFI));
+      mangler.setArgumentClosurePropPreviousArg(closureArgIndex, argElmt.otherArgIdx);
     }
   }
 
   return BridgedOwnedString(mangler.mangle());
 }
 
-BridgedGlobalVar BridgedPassContext::createGlobalVariable(BridgedStringRef name, BridgedType type, BridgedLinkage linkage, bool isLet) const {
-  auto *global = SILGlobalVariable::create(
-      *invocation->getPassManager()->getModule(),
-      (swift::SILLinkage)linkage, IsNotSerialized,
-      name.unbridged(), type.unbridged());
-  if (isLet)
-    global->setLet(true);
-  return {global};
+BridgedOwnedString BridgedPassContext::mangleWithConstCaptureArgs(
+  BridgedArrayRef bridgedConstArgs, BridgedFunction applySiteCallee
+) const {
+
+  struct ConstArgElement {
+    SwiftInt argIdx;
+    BridgedValue constValue;
+  };
+
+  auto pass = Demangle::SpecializationPass::CapturePropagation;
+  auto serializedKind = applySiteCallee.getFunction()->getSerializedKind();
+  Mangle::FunctionSignatureSpecializationMangler mangler(applySiteCallee.getFunction()->getASTContext(),
+      pass, serializedKind, applySiteCallee.getFunction());
+
+  auto constArgs = bridgedConstArgs.unbridged<ConstArgElement>();
+
+  for (ConstArgElement argElmt : constArgs) {
+    auto constArgInst = cast<SingleValueInstruction>(argElmt.constValue.getSILValue());
+    mangler.setArgumentConstantProp(argElmt.argIdx, constArgInst);
+  }
+
+  return BridgedOwnedString(mangler.mangle());
+}
+
+BridgedOwnedString BridgedPassContext::mangleWithBoxToStackPromotedArgs(
+  BridgedArrayRef bridgedPromotedArgIndices,
+  BridgedFunction bridgedOriginalFunction
+) const {
+  auto *original = bridgedOriginalFunction.getFunction();
+  Mangle::FunctionSignatureSpecializationMangler mangler(original->getASTContext(),
+                                                         Demangle::SpecializationPass::AllocBoxToStack,
+                                                         original->getSerializedKind(), original);
+  for (SwiftInt i : bridgedPromotedArgIndices.unbridged<SwiftInt>()) {
+    mangler.setArgumentBoxToStack((unsigned)i);
+  }
+  return BridgedOwnedString(mangler.mangle());
 }
 
 void BridgedPassContext::fixStackNesting(BridgedFunction function) const {
@@ -347,36 +338,16 @@ void BridgedPassContext::fixStackNesting(BridgedFunction function) const {
     case StackNesting::Changes::None:
       break;
     case StackNesting::Changes::Instructions:
-      invocation->notifyChanges(SILAnalysis::InvalidationKind::Instructions);
+      invocation->notifyChanges(SILContext::NotificationKind::Instructions);
       break;
     case StackNesting::Changes::CFG:
-      invocation->notifyChanges(SILAnalysis::InvalidationKind::BranchesAndInstructions);
+      invocation->notifyChanges(SILContext::NotificationKind::Instructions);
+      invocation->notifyChanges(SILContext::NotificationKind::Branches);
       break;
   }
   invocation->setNeedFixStackNesting(false);
 }
 
-OptionalBridgedFunction BridgedPassContext::lookupStdlibFunction(BridgedStringRef name) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  SmallVector<ValueDecl *, 1> results;
-  mod->getASTContext().lookupInSwiftModule(name.unbridged(), results);
-  if (results.size() != 1)
-    return {nullptr};
-
-  auto *decl = dyn_cast<FuncDecl>(results.front());
-  if (!decl)
-    return {nullptr};
-
-  SILDeclRef declRef(decl, SILDeclRef::Kind::Func);
-  SILOptFunctionBuilder funcBuilder(*invocation->getTransform());
-  return {funcBuilder.getOrCreateFunction(SILLocation(decl), declRef, NotForDefinition)};
-}
-
-OptionalBridgedFunction BridgedPassContext::lookUpNominalDeinitFunction(BridgedDeclObj nominal)  const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  return {mod->lookUpMoveOnlyDeinitFunction(nominal.getAs<swift::NominalTypeDecl>())};
-}
-
 bool BridgedPassContext::enableSimplificationFor(BridgedInstruction inst) const {
   // Fast-path check.
   if (SimplifyInstructionTest.empty() && !SILPassManager::isAnyPassDisabled())
@@ -398,62 +369,15 @@ bool BridgedPassContext::enableSimplificationFor(BridgedInstruction inst) const
 }
 
 BridgedFunction BridgedPassContext::
-createEmptyFunction(BridgedStringRef name,
-                    const BridgedParameterInfo * _Nullable bridgedParams,
-                    SwiftInt paramCount,
-                    bool hasSelfParam,
-                    BridgedFunction fromFunc) const {
-  swift::SILModule *mod = invocation->getPassManager()->getModule();
-  SILFunction *fromFn = fromFunc.getFunction();
-
-  llvm::SmallVector<SILParameterInfo> params;
-  for (unsigned idx = 0; idx < paramCount; ++idx) {
-    params.push_back(bridgedParams[idx].unbridged());
-  }
-
-  CanSILFunctionType fTy = fromFn->getLoweredFunctionType();
-  assert(fromFn->getGenericSignature().isNull() && "generic functions are not supported");
-
-  auto extInfo = fTy->getExtInfo();
-  if (fTy->hasSelfParam() && !hasSelfParam)
-    extInfo = extInfo.withRepresentation(SILFunctionTypeRepresentation::Thin);
-
-  CanSILFunctionType newTy = SILFunctionType::get(
-      /*GenericSignature=*/nullptr, extInfo, fTy->getCoroutineKind(),
-      fTy->getCalleeConvention(), params, fTy->getYields(),
-      fTy->getResults(), fTy->getOptionalErrorResult(),
-      SubstitutionMap(), SubstitutionMap(),
-      mod->getASTContext());
-
-  SILOptFunctionBuilder functionBuilder(*invocation->getTransform());
-
-  SILFunction *newF = functionBuilder.createFunction(
-      fromFn->getLinkage(), name.unbridged(), newTy, nullptr,
-      fromFn->getLocation(), fromFn->isBare(), fromFn->isTransparent(),
-      fromFn->getSerializedKind(), IsNotDynamic, IsNotDistributed,
-      IsNotRuntimeAccessible, fromFn->getEntryCount(), fromFn->isThunk(),
-      fromFn->getClassSubclassScope(), fromFn->getInlineStrategy(),
-      fromFn->getEffectsKind(), nullptr, fromFn->getDebugScope());
-
-  return {newF};
-}
-
-void BridgedPassContext::moveFunctionBody(BridgedFunction sourceFunc, BridgedFunction destFunc) const {
-  SILFunction *sourceFn = sourceFunc.getFunction();
-  SILFunction *destFn = destFunc.getFunction();
-  destFn->moveAllBlocksFromOtherFunction(sourceFn);
-  invocation->getPassManager()->invalidateAnalysis(sourceFn, SILAnalysis::InvalidationKind::Everything);
-  invocation->getPassManager()->invalidateAnalysis(destFn, SILAnalysis::InvalidationKind::Everything);
-}
-
-BridgedFunction BridgedPassContext::
-ClosureSpecializer_createEmptyFunctionWithSpecializedSignature(BridgedStringRef specializedName,
-                                            const BridgedParameterInfo * _Nullable specializedBridgedParams,
-                                            SwiftInt paramCount,
-                                            BridgedFunction bridgedApplySiteCallee,
-                                            bool isSerialized)  const {
-  auto *applySiteCallee = bridgedApplySiteCallee.getFunction();
-  auto applySiteCalleeType = applySiteCallee->getLoweredFunctionType();
+createSpecializedFunctionDeclaration(BridgedStringRef specializedName,
+                                     const BridgedParameterInfo * _Nullable specializedBridgedParams,
+                                     SwiftInt paramCount,
+                                     BridgedFunction bridgedOriginal,
+                                     bool makeThin,
+                                     bool makeBare,
+                                     bool preserveGenericSignature) const {
+  auto *original = bridgedOriginal.getFunction();
+  auto originalType = original->getLoweredFunctionType();
 
   llvm::SmallVector<SILParameterInfo> specializedParams;
   for (unsigned idx = 0; idx < paramCount; ++idx) {
@@ -463,18 +387,20 @@ ClosureSpecializer_createEmptyFunctionWithSpecializedSignature(BridgedStringRef
   // The specialized function is always a thin function. This is important
   // because we may add additional parameters after the Self parameter of
   // witness methods. In this case the new function is not a method anymore.
-  auto extInfo = applySiteCalleeType->getExtInfo();
-  extInfo = extInfo.withRepresentation(SILFunctionTypeRepresentation::Thin);
+  auto extInfo = originalType->getExtInfo();
+  if (makeThin)
+    extInfo = extInfo.withRepresentation(SILFunctionTypeRepresentation::Thin);
 
   auto ClonedTy = SILFunctionType::get(
-      applySiteCalleeType->getInvocationGenericSignature(), extInfo,
-      applySiteCalleeType->getCoroutineKind(),
-      applySiteCalleeType->getCalleeConvention(), specializedParams,
-      applySiteCalleeType->getYields(), applySiteCalleeType->getResults(),
-      applySiteCalleeType->getOptionalErrorResult(),
-      applySiteCalleeType->getPatternSubstitutions(),
-      applySiteCalleeType->getInvocationSubstitutions(),
-      applySiteCallee->getModule().getASTContext());
+      preserveGenericSignature ? originalType->getInvocationGenericSignature() : GenericSignature(),
+      extInfo,
+      originalType->getCoroutineKind(),
+      originalType->getCalleeConvention(), specializedParams,
+      originalType->getYields(), originalType->getResults(),
+      originalType->getOptionalErrorResult(),
+      preserveGenericSignature ? originalType->getPatternSubstitutions() : SubstitutionMap(),
+      preserveGenericSignature ? originalType->getInvocationSubstitutions() : SubstitutionMap(),
+      original->getModule().getASTContext());
 
   SILOptFunctionBuilder functionBuilder(*invocation->getTransform());
 
@@ -488,23 +414,24 @@ ClosureSpecializer_createEmptyFunctionWithSpecializedSignature(BridgedStringRef
       // It's also important to disconnect this specialized function from any
       // classes (the classSubclassScope), because that may incorrectly
       // influence the linkage.
-      getSpecializedLinkage(applySiteCallee, applySiteCallee->getLinkage()), specializedName.unbridged(),
-      ClonedTy, applySiteCallee->getGenericEnvironment(),
-      applySiteCallee->getLocation(), IsBare, applySiteCallee->isTransparent(),
-      isSerialized ? IsSerialized : IsNotSerialized, IsNotDynamic, IsNotDistributed,
-      IsNotRuntimeAccessible, applySiteCallee->getEntryCount(),
-      applySiteCallee->isThunk(),
+      getSpecializedLinkage(original, original->getLinkage()), specializedName.unbridged(),
+      ClonedTy,
+      preserveGenericSignature ? original->getGenericEnvironment() : nullptr,
+      original->getLocation(), makeBare ? IsBare : original->isBare(), original->isTransparent(),
+      original->getSerializedKind(), IsNotDynamic, IsNotDistributed,
+      IsNotRuntimeAccessible, original->getEntryCount(),
+      original->isThunk(),
       /*classSubclassScope=*/SubclassScope::NotApplicable,
-      applySiteCallee->getInlineStrategy(), applySiteCallee->getEffectsKind(),
-      applySiteCallee, applySiteCallee->getDebugScope());
+      original->getInlineStrategy(), original->getEffectsKind(),
+      original, original->getDebugScope());
   
-  if (!applySiteCallee->hasOwnership()) {
+  if (!original->hasOwnership()) {
     specializedApplySiteCallee->setOwnershipEliminated();
   }
   
-  for (auto &Attr : applySiteCallee->getSemanticsAttrs())
+  for (auto &Attr : original->getSemanticsAttrs())
     specializedApplySiteCallee->addSemanticsAttr(Attr);
-  
+
   return {specializedApplySiteCallee};
 }
 
@@ -513,8 +440,9 @@ bool BridgedPassContext::completeLifetime(BridgedValue value) const {
   SILFunction *f = v->getFunction();
   DeadEndBlocks *deb = invocation->getPassManager()->getAnalysis<DeadEndBlocksAnalysis>()->get(f);
   DominanceInfo *domInfo = invocation->getPassManager()->getAnalysis<DominanceAnalysis>()->get(f);
-  OSSALifetimeCompletion completion(f, domInfo, *deb);
-  auto result = completion.completeOSSALifetime(v, OSSALifetimeCompletion::Boundary::Availability);
+  OSSACompleteLifetime completion(f, domInfo, *deb);
+  auto result = completion.completeOSSALifetime(
+      v, OSSACompleteLifetime::Boundary::Availability);
   return result == LifetimeCompletion::WasCompleted;
 }
 
@@ -530,10 +458,7 @@ BridgedDynamicCastResult classifyDynamicCastBridged(BridgedCanType sourceTy, Bri
   static_assert((int)DynamicCastFeasibility::WillFail    == (int)BridgedDynamicCastResult::willFail);
 
   return static_cast<BridgedDynamicCastResult>(
-    classifyDynamicCast(function.getFunction()->getModule().getSwiftModule(),
-                        sourceTy.unbridged(),
-                        destTy.unbridged(),
-                        sourceTypeIsExact));
+    classifyDynamicCast(function.getFunction(), sourceTy.unbridged(), destTy.unbridged(), sourceTypeIsExact));
 }
 
 BridgedDynamicCastResult classifyDynamicCastBridged(BridgedInstruction inst) {
@@ -551,122 +476,22 @@ BridgedCalleeAnalysis::CalleeList BridgedCalleeAnalysis::getDestructors(BridgedT
   return ca->getDestructors(type.unbridged(), isExactType);
 }
 
-// Need to put ClonerWithFixedLocation into namespace swift to forward reference
-// it in OptimizerBridging.h.
-namespace swift {
-
-class ClonerWithFixedLocation : public SILCloner<ClonerWithFixedLocation> {
-  friend class SILInstructionVisitor<ClonerWithFixedLocation>;
-  friend class SILCloner<ClonerWithFixedLocation>;
-
-  SILDebugLocation insertLoc;
-
-public:
-  ClonerWithFixedLocation(SILGlobalVariable *gVar)
-  : SILCloner<ClonerWithFixedLocation>(gVar),
-  insertLoc(ArtificialUnreachableLocation(), nullptr) {}
-
-  ClonerWithFixedLocation(SILInstruction *insertionPoint)
-  : SILCloner<ClonerWithFixedLocation>(*insertionPoint->getFunction()),
-  insertLoc(insertionPoint->getDebugLocation()) {
-    Builder.setInsertionPoint(insertionPoint);
-  }
-
-  SILValue getClonedValue(SILValue v) {
-    return getMappedValue(v);
-  }
-
-  void cloneInst(SILInstruction *inst) {
-    visit(inst);
-  }
-
-protected:
-
-  SILLocation remapLocation(SILLocation loc) {
-    return insertLoc.getLocation();
-  }
-
-  const SILDebugScope *remapScope(const SILDebugScope *DS) {
-    return insertLoc.getScope();
-  }
-};
-
-} // namespace swift
-
-BridgedCloner::BridgedCloner(BridgedGlobalVar var, BridgedPassContext context)
-  : cloner(new ClonerWithFixedLocation(var.getGlobal())) {
-  context.invocation->notifyNewCloner();
-}
-
-BridgedCloner::BridgedCloner(BridgedInstruction inst,
-                             BridgedPassContext context)
-    : cloner(new ClonerWithFixedLocation(inst.unbridged())) {
-  context.invocation->notifyNewCloner();
-}
-
-void BridgedCloner::destroy(BridgedPassContext context) {
-  delete cloner;
-  cloner = nullptr;
-  context.invocation->notifyClonerDestroyed();
-}
-
-BridgedValue BridgedCloner::getClonedValue(BridgedValue v) {
-  return {cloner->getClonedValue(v.getSILValue())};
-}
-
-bool BridgedCloner::isValueCloned(BridgedValue v) const {
-  return cloner->isValueCloned(v.getSILValue());
-}
-
-void BridgedCloner::clone(BridgedInstruction inst) {
-  cloner->cloneInst(inst.unbridged());
-}
-
-void BridgedCloner::recordFoldedValue(BridgedValue origValue, BridgedValue mappedValue) {
-  cloner->recordFoldedValue(origValue.getSILValue(), mappedValue.getSILValue());
-}
-
-namespace swift {
-  class ClosureSpecializationCloner: public SILClonerWithScopes<ClosureSpecializationCloner> {
-    friend class SILInstructionVisitor<ClosureSpecializationCloner>;
-    friend class SILCloner<ClosureSpecializationCloner>;
-  public: 
-    using SuperTy = SILClonerWithScopes<ClosureSpecializationCloner>;
-    ClosureSpecializationCloner(SILFunction &emptySpecializedFunction): SuperTy(emptySpecializedFunction) {}
-  };
-} // namespace swift
-
-BridgedSpecializationCloner::BridgedSpecializationCloner(BridgedFunction emptySpecializedFunction): 
-  closureSpecCloner(new ClosureSpecializationCloner(*emptySpecializedFunction.getFunction())) {}
-
-BridgedFunction BridgedSpecializationCloner::getCloned() const {
-  return { &closureSpecCloner->getBuilder().getFunction() };
-}
-
-BridgedBasicBlock BridgedSpecializationCloner::getClonedBasicBlock(BridgedBasicBlock originalBasicBlock) const {
-  return { closureSpecCloner->getOpBasicBlock(originalBasicBlock.unbridged()) };
-}
-
-void BridgedSpecializationCloner::cloneFunctionBody(BridgedFunction originalFunction, BridgedBasicBlock clonedEntryBlock, BridgedValueArray clonedEntryBlockArgs) const {
-  llvm::SmallVector<swift::SILValue, 16> clonedEntryBlockArgsStorage;
-  auto clonedEntryBlockArgsArrayRef = clonedEntryBlockArgs.getValues(clonedEntryBlockArgsStorage);
-  closureSpecCloner->cloneFunctionBody(originalFunction.getFunction(), clonedEntryBlock.unbridged(), clonedEntryBlockArgsArrayRef);
-}
-
 void BridgedBuilder::destroyCapturedArgs(BridgedInstruction partialApply) const {
   if (auto *pai = llvm::dyn_cast<PartialApplyInst>(partialApply.unbridged()); pai->isOnStack()) {
     auto b = unbridged();
-    return swift::insertDestroyOfCapturedArguments(pai, b); 
+    return swift::insertDestroyOfCapturedArguments(pai, b);
   } else {
-    assert(false && "`destroyCapturedArgs` must only be called on a `partial_apply` on stack!");   
+    assert(false && "`destroyCapturedArgs` must only be called on a `partial_apply` on stack!");
   }
 }
 
-void verifierError(BridgedStringRef message,
-                   OptionalBridgedInstruction atInstruction,
-                   OptionalBridgedArgument atArgument) {
-  Twine msg(message.unbridged());
-  verificationFailure(msg, atInstruction.unbridged(), atArgument.unbridged(), /*extraContext=*/nullptr);
+//===----------------------------------------------------------------------===//
+//                                Test
+//===----------------------------------------------------------------------===//
+
+void registerFunctionTest(BridgedStringRef name, void *nativeSwiftContext) {
+  swift::test::FunctionTest::createNativeSwiftFunctionTest(
+      name.unbridged(), nativeSwiftContext, /*isSILTest=*/ false);
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/SILOptimizer/Utils/OwnershipOptUtils.cpp b/lib/SILOptimizer/Utils/OwnershipOptUtils.cpp
index baf9ab6fea0ae..abd02ac498bf6 100644
--- a/lib/SILOptimizer/Utils/OwnershipOptUtils.cpp
+++ b/lib/SILOptimizer/Utils/OwnershipOptUtils.cpp
@@ -805,10 +805,6 @@ struct OwnershipLifetimeExtender {
   /// the BorrowedValue that begins the scope.
   SILValue borrowOverSingleUse(SILValue newValue,
                                Operand *singleGuaranteedUse);
-
-  SILValue
-  borrowOverSingleNonLifetimeEndingUser(SILValue newValue,
-                                        SILInstruction *nonLifetimeEndingUser);
 };
 
 } // end anonymous namespace
@@ -973,7 +969,14 @@ BeginBorrowInst *OwnershipLifetimeExtender::borrowCopyOverGuaranteedUsers(
   // Create destroys at the end of copy's lifetime. This only needs to consider
   // uses that end the borrow scope.
   {
-    ValueLifetimeAnalysis lifetimeAnalysis(copy, borrow->getEndBorrows());
+    SmallVector<SILInstruction *, 16> users;
+    for (auto *user : guaranteedUsers) {
+      users.push_back(user);
+    }
+    for (auto *user : borrow->getEndBorrows()) {
+      users.push_back(user);
+    }
+    ValueLifetimeAnalysis lifetimeAnalysis(copy, users);
     ValueLifetimeBoundary copyBoundary;
     lifetimeAnalysis.computeLifetimeBoundary(copyBoundary);
 
@@ -1092,27 +1095,6 @@ OwnershipLifetimeExtender::borrowOverSingleUse(SILValue newValue,
   return newBeginBorrow;
 }
 
-SILValue OwnershipLifetimeExtender::borrowOverSingleNonLifetimeEndingUser(
-    SILValue newValue, SILInstruction *nonLifetimeEndingUser) {
-  // Avoid borrowing guaranteed function arguments.
-  if (isa<SILFunctionArgument>(newValue) &&
-      newValue->getOwnershipKind() == OwnershipKind::Guaranteed) {
-    return newValue;
-  }
-  auto borrowPt = newValue->getNextInstruction()->getIterator();
-  return borrowCopyOverGuaranteedUsers(
-      newValue, borrowPt, ArrayRef<SILInstruction *>(nonLifetimeEndingUser));
-}
-
-SILValue swift::makeGuaranteedValueAvailable(SILValue value,
-                                             SILInstruction *user,
-                                             DeadEndBlocks &deBlocks,
-                                             InstModCallbacks callbacks) {
-  OwnershipFixupContext ctx{callbacks, deBlocks};
-  OwnershipLifetimeExtender extender{ctx};
-  return extender.borrowOverSingleNonLifetimeEndingUser(value, user);
-}
-
 //===----------------------------------------------------------------------===//
 //                OwnershipRAUWUtility - RAUW + fix ownership
 //===----------------------------------------------------------------------===//
@@ -1241,13 +1223,14 @@ SILValue OwnershipRAUWPrepare::prepareReplacement(SILValue newValue) {
       OwnershipRAUWHelper::hasValidRAUWOwnership(oldValue, newValue,
                                                  ctx.guaranteedUsePoints) &&
       "Should have checked if can perform this operation before calling it?!");
-  // If our new value is just none, we can pass anything to it so just RAUW
+  // If our new value is just none, we can pass it to anything so just RAUW
   // and return.
   //
   // NOTE: This handles RAUWing with undef.
-  if (newValue->getOwnershipKind() == OwnershipKind::None)
+  if (newValue->getOwnershipKind() == OwnershipKind::None) {
+    cleanupOperandsBeforeDeletion(getConsumingPoint(), ctx.callbacks);
     return newValue;
-
+  }
   assert(oldValue->getOwnershipKind() != OwnershipKind::None);
 
   switch (oldValue->getOwnershipKind()) {
diff --git a/lib/SILOptimizer/Utils/PartitionUtils.cpp b/lib/SILOptimizer/Utils/PartitionUtils.cpp
index d0dd74a1e2759..0974dcc9fcd5a 100644
--- a/lib/SILOptimizer/Utils/PartitionUtils.cpp
+++ b/lib/SILOptimizer/Utils/PartitionUtils.cpp
@@ -46,7 +46,7 @@ void PartitionOpError::SentNeverSendableError::print(
      << "        ID:  %%" << sentElement << "\n"
      << "        Rep: " << *info.getRepresentative(sentElement)
      << "        Dynamic Isolation Region: ";
-  isolationRegionInfo.printForOneLineLogging(os);
+  isolationRegionInfo.printForOneLineLogging(info.getFunction(), os);
   os << '\n';
   if (auto isolatedValue = isolationRegionInfo->maybeGetIsolatedValue()) {
     os << "        Isolated Value: " << isolatedValue;
@@ -90,7 +90,7 @@ void PartitionOpError::InOutSendingNotDisconnectedAtExitError::print(
      << "        ID:  %%" << inoutSendingElement << "\n"
      << "        Rep: " << valueMap.getRepresentativeValue(inoutSendingElement)
      << "        Dynamic Isolation Region: ";
-  isolationInfo.printForOneLineLogging(os);
+  isolationInfo.printForOneLineLogging(valueMap.getFunction(), os);
   os << '\n';
 }
 
@@ -102,6 +102,15 @@ void PartitionOpError::NonSendableIsolationCrossingResultError::print(
      << '\n';
 }
 
+void PartitionOpError::InOutSendingReturnedError::print(
+    llvm::raw_ostream &os, RegionAnalysisValueMap &valueMap) const {
+  os << "    Emitting Error. Kind: InOutSendingReturnedError!\n"
+     << "        ID:  %%" << inoutSendingElement << '\n'
+     << "        Rep: " << valueMap.getRepresentativeValue(inoutSendingElement)
+     << "        Returned Value ID:  %%" << returnedValue << '\n'
+     << "        Rep: " << valueMap.getRepresentativeValue(returnedValue);
+}
+
 //===----------------------------------------------------------------------===//
 //                             MARK: PartitionOp
 //===----------------------------------------------------------------------===//
@@ -113,55 +122,64 @@ void PartitionOp::print(llvm::raw_ostream &os, bool extraSpace) const {
     os << "assign ";
     if (extraSpace)
       os << extraSpaceLiteral;
-    os << "%%" << opArgs[0] << " = %%" << opArgs[1];
+    os << "%%" << getOpArg1() << " = %%" << getOpArg2();
     break;
   }
   case PartitionOpKind::AssignFresh:
-    os << "assign_fresh %%" << opArgs[0];
+    os << "assign_fresh %%" << getOpArg1();
     break;
   case PartitionOpKind::Send: {
     os << "send ";
     if (extraSpace)
       os << extraSpaceLiteral;
-    os << "%%" << opArgs[0];
+    os << "%%" << getOpArg1();
     break;
   }
   case PartitionOpKind::UndoSend: {
     os << "undo_send ";
     if (extraSpace)
       os << extraSpaceLiteral;
-    os << "%%" << opArgs[0];
+    os << "%%" << getOpArg1();
     break;
   }
   case PartitionOpKind::Merge: {
     os << "merge ";
     if (extraSpace)
       os << extraSpaceLiteral;
-    os << "%%" << opArgs[0] << " with %%" << opArgs[1];
+    os << "%%" << getOpArg1() << " with %%" << getOpArg2();
     break;
   }
   case PartitionOpKind::Require: {
     os << "require ";
+    if (getOptions().containsOnly(
+            PartitionOp::Flag::RequireOfMutableBaseOfSendableValue))
+      os << "[mutable_base_of_sendable_val] ";
     if (extraSpace)
       os << extraSpaceLiteral;
-    os << "%%" << opArgs[0];
+    os << "%%" << getOpArg1();
     break;
   }
   case PartitionOpKind::UnknownPatternError:
     os << "unknown pattern error ";
-    os << "%%" << opArgs[0];
+    os << "%%" << getOpArg1();
     break;
   case PartitionOpKind::InOutSendingAtFunctionExit:
     os << "inout_sending_at_function_exit ";
     if (extraSpace)
       os << extraSpaceLiteral;
-    os << "%%" << opArgs[0];
+    os << "%%" << getOpArg1();
     break;
   case PartitionOpKind::NonSendableIsolationCrossingResult:
     os << "nonsendable_isolationcrossing_result ";
     if (extraSpace)
       os << extraSpaceLiteral;
-    os << "%%" << opArgs[0];
+    os << "%%" << getOpArg1();
+    break;
+  case PartitionOpKind::AssignFreshAssign:
+    os << "assign_fresh_assign ";
+    if (extraSpace)
+      os << extraSpaceLiteral;
+    os << "%%" << getOpArg1() << " = %%" << getOpArg2();
     break;
   }
   os << ": " << *getSourceInst();
diff --git a/lib/SILOptimizer/Utils/PerformanceInlinerUtils.cpp b/lib/SILOptimizer/Utils/PerformanceInlinerUtils.cpp
index 4f2a4b1164fe5..ad677b85b9895 100644
--- a/lib/SILOptimizer/Utils/PerformanceInlinerUtils.cpp
+++ b/lib/SILOptimizer/Utils/PerformanceInlinerUtils.cpp
@@ -135,6 +135,9 @@ SILValue swift::stripFunctionConversions(SILValue val) {
       val = cvt->getOperand();
       result = val;
       continue;
+    } else if (auto md = dyn_cast<MarkDependenceInst>(val)) {
+      val = md->getValue();
+      result = val;
     } else {
       break;
     }
@@ -758,6 +761,7 @@ SILFunction *swift::getEligibleFunction(FullApplySite AI,
   // If our inline selection is only always inline, do a quick check if we have
   // an always inline function and bail otherwise.
   if (WhatToInline == InlineSelection::OnlyInlineAlways &&
+      Callee->getInlineStrategy() != HeuristicAlwaysInline &&
       Callee->getInlineStrategy() != AlwaysInline) {
     return nullptr;
   }
@@ -870,7 +874,7 @@ SILFunction *swift::getEligibleFunction(FullApplySite AI,
     if (!isCallerAndCalleeLayoutConstraintsCompatible(AI) &&
         // TODO: revisit why we can make an exception for inline-always
         // functions. Some tests depend on it.
-        Callee->getInlineStrategy() != AlwaysInline && !Callee->isTransparent())
+        Callee->getInlineStrategy() != HeuristicAlwaysInline && !Callee->isTransparent())
       return nullptr;
   }
 
diff --git a/lib/SILOptimizer/Utils/RegionIsolation.cpp b/lib/SILOptimizer/Utils/RegionIsolation.cpp
index 8002de4af0f22..1a5e982cf73ab 100644
--- a/lib/SILOptimizer/Utils/RegionIsolation.cpp
+++ b/lib/SILOptimizer/Utils/RegionIsolation.cpp
@@ -26,7 +26,7 @@ LoggingFlag swift::regionisolation::ENABLE_LOGGING;
 static llvm::cl::opt<LoggingFlag, true> // The parser
     RegionBasedIsolationLog(
         "sil-regionbasedisolation-log",
-        llvm::cl::desc("Enable logging for SIL region based isolation "
+        llvm::cl::desc("Enable logging for SIL region-based isolation "
                        "diagnostics"),
         llvm::cl::Hidden,
         llvm::cl::values(
diff --git a/lib/SILOptimizer/Utils/SILInliner.cpp b/lib/SILOptimizer/Utils/SILInliner.cpp
index 7c8f8283889ce..87223592a1091 100644
--- a/lib/SILOptimizer/Utils/SILInliner.cpp
+++ b/lib/SILOptimizer/Utils/SILInliner.cpp
@@ -128,6 +128,32 @@ class BeginApplySite {
       collectAbortApply(abortApply);
       endBorrowInsertPts.push_back(&*std::next(abortApply->getIterator()));
     }
+
+    // We may have a mark_dependence/mark_dependence_addr on the coroutine's
+    // token. This is needed to represent lifetime dependence on values created
+    // within the coroutine. Delete such mark_dependence instructions since the
+    // dependencies on values created within the coroutine will be exposed after
+    // inlining.
+    if (BeginApply->getCalleeFunction()
+            ->getLoweredFunctionType()
+            ->hasLifetimeDependencies()) {
+      SmallVector<SILInstruction *> toDelete;
+      for (auto *tokenUser : BeginApply->getTokenResult()->getUsers()) {
+        auto mdi = MarkDependenceInstruction(tokenUser);
+        if (!mdi) {
+          continue;
+        }
+        assert(mdi.isNonEscaping());
+        if (auto *valueMDI = dyn_cast<MarkDependenceInst>(*mdi)) {
+          valueMDI->replaceAllUsesWith(valueMDI->getValue());
+        }
+        toDelete.push_back(*mdi);
+      }
+
+      for (auto *inst : toDelete) {
+        inst->eraseFromParent();
+      }
+    }
   }
 
   // Split the basic block before the end/abort_apply. We will insert code
@@ -281,10 +307,10 @@ class BeginApplySite {
 
 namespace swift {
 class SILInlineCloner
-    : public TypeSubstCloner<SILInlineCloner, SILOptFunctionBuilder> {
+    : public TypeSubstCloner<SILInlineCloner> {
   friend class SILInstructionVisitor<SILInlineCloner>;
   friend class SILCloner<SILInlineCloner>;
-  using SuperTy = TypeSubstCloner<SILInlineCloner, SILOptFunctionBuilder>;
+  using SuperTy = TypeSubstCloner<SILInlineCloner>;
   using InlineKind = SILInliner::InlineKind;
 
   SILOptFunctionBuilder &FuncBuilder;
@@ -350,7 +376,8 @@ class SILInlineCloner
 
   SILLocation remapLocation(SILLocation InLoc) {
     // For performance inlining return the original location.
-    if (IKind == InlineKind::PerformanceInline)
+    if (IKind == InlineKind::PerformanceInline ||
+        IKind == InlineKind::InlineAlwaysInline)
       return InLoc;
     // Inlined location wraps the call site that is being inlined, regardless of
     // the input location.
@@ -500,6 +527,9 @@ void SILInlineCloner::cloneInline(ArrayRef<SILValue> AppliedArgs) {
           if (!enableLexicalLifetimes)
             continue;
 
+          if (!Original.isDeinitBarrier())
+            continue;
+
           // Exclusive mutating accesses don't entail a lexical scope.
           if (paramInfo.getConvention() == ParameterConvention::Indirect_Inout)
             continue;
@@ -738,6 +768,14 @@ Scope scopeForArgument(Scope nonlexicalScope, SILValue callArg, unsigned index,
     // the argument.  Just do an ownership conversion if needed.
     return nonlexicalScope;
   }
+
+  // Use non-lexical scope for functions returning @guaranteed results.
+  // TODO: Represent the SILFunctionArgument of borrow accessors as non-lexical
+  // during SILGen.
+  if (callee->getConventions().hasGuaranteedResult()) {
+    return nonlexicalScope;
+  }
+
   // Lexical lifetimes are enabled, the function argument's lifetime is
   // lexical, but the caller's value is not lexical.  Extra care is required to
   // maintain the function argument's lifetime.  We need to add a lexical
@@ -1023,6 +1061,7 @@ InlineCost swift::instructionInlineCost(SILInstruction &I) {
   case SILInstructionKind::UnwindInst:
   case SILInstructionKind::YieldInst:
   case SILInstructionKind::EndCOWMutationInst:
+  case SILInstructionKind::EndCOWMutationAddrInst:
     return InlineCost::Free;
 
   // Turning the task reference into a continuation should be basically free.
@@ -1050,7 +1089,6 @@ InlineCost swift::instructionInlineCost(SILInstruction &I) {
   case SILInstructionKind::ValueMetatypeInst:
   case SILInstructionKind::WitnessMethodInst:
   case SILInstructionKind::AssignInst:
-  case SILInstructionKind::AssignByWrapperInst:
   case SILInstructionKind::AssignOrInitInst:
   case SILInstructionKind::CheckedCastBranchInst:
   case SILInstructionKind::CheckedCastAddrBranchInst:
@@ -1092,6 +1130,7 @@ InlineCost swift::instructionInlineCost(SILInstruction &I) {
   case SILInstructionKind::DynamicMethodBranchInst:
   case SILInstructionKind::EnumInst:
   case SILInstructionKind::IndexAddrInst:
+  case SILInstructionKind::VectorBaseAddrInst:
   case SILInstructionKind::TailAddrInst:
   case SILInstructionKind::IndexRawPointerInst:
   case SILInstructionKind::InitEnumDataAddrInst:
diff --git a/lib/SILOptimizer/Utils/SILIsolationInfo.cpp b/lib/SILOptimizer/Utils/SILIsolationInfo.cpp
index bcf7440a40b83..91fc48c5634ca 100644
--- a/lib/SILOptimizer/Utils/SILIsolationInfo.cpp
+++ b/lib/SILOptimizer/Utils/SILIsolationInfo.cpp
@@ -13,9 +13,15 @@
 #include "swift/SILOptimizer/Utils/SILIsolationInfo.h"
 
 #include "swift/AST/ASTWalker.h"
+#include "swift/AST/ConformanceLookup.h"
+#include "swift/AST/DistributedDecl.h"
+#include "swift/AST/ExistentialLayout.h"
 #include "swift/AST/Expr.h"
+#include "swift/AST/PackConformance.h"
+#include "swift/AST/ProtocolConformance.h"
 #include "swift/SIL/AddressWalker.h"
 #include "swift/SIL/ApplySite.h"
+#include "swift/SIL/DynamicCasts.h"
 #include "swift/SIL/InstructionUtils.h"
 #include "swift/SIL/PatternMatch.h"
 #include "swift/SIL/SILGlobalVariable.h"
@@ -357,6 +363,69 @@ inferIsolationInfoForTempAllocStack(AllocStackInst *asi) {
   return SILIsolationInfo::get(targetOperand->getUser());
 }
 
+static SILValue lookThroughNonVarDeclOwnershipInsts(SILValue v) {
+  while (true) {
+    if (auto *svi = dyn_cast<SingleValueInstruction>(v)) {
+      if (isa<CopyValueInst>(svi)) {
+        v = svi->getOperand(0);
+        continue;
+      }
+
+      if (auto *bbi = dyn_cast<BeginBorrowInst>(v)) {
+        if (!bbi->isFromVarDecl()) {
+          v = bbi->getOperand();
+          continue;
+        }
+        return v;
+      }
+
+      if (auto *mvi = dyn_cast<MoveValueInst>(v)) {
+        if (!mvi->isFromVarDecl()) {
+          v = mvi->getOperand();
+          continue;
+        }
+
+        return v;
+      }
+    }
+
+    return v;
+  }
+}
+
+/// See if \p pai has at least one nonisolated(unsafe) capture and that all
+/// captures are either nonisolated(unsafe) or sendable.
+static bool isPartialApplyNonisolatedUnsafe(PartialApplyInst *pai) {
+  bool foundOneNonIsolatedUnsafe = false;
+  for (auto &op : pai->getArgumentOperands()) {
+    if (SILIsolationInfo::isSendableType(op.get()))
+      continue;
+
+    // Normally we would not look through copy_value, begin_borrow, or
+    // move_value since this is meant to find the inherent isolation of a
+    // specific element. But since we are checking for captures rather
+    // than the actual value itself (just for unsafe nonisolated
+    // purposes), it is ok.
+    //
+    // E.x.: As an example of something we want to prevent, consider an
+    // invocation of a nonisolated function that is a parameter to an
+    // @MainActor function. That means from a region isolation
+    // perspective, the function parameter is in the MainActor region, but
+    // the actual function itself is not MainActor isolated, since the
+    // function will not hop onto the main actor.
+    //
+    // TODO: We should use some of the shared infrastructure to find the
+    // underlying value of op.get(). This is conservatively correct for
+    // now.
+    auto value = lookThroughNonVarDeclOwnershipInsts(op.get());
+    if (!SILIsolationInfo::get(value).isUnsafeNonIsolated())
+      return false;
+    foundOneNonIsolatedUnsafe = true;
+  }
+
+  return foundOneNonIsolatedUnsafe;
+}
+
 SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
   if (auto fas = FullApplySite::isa(inst)) {
     // Before we do anything, see if we have a sending result. In such a case,
@@ -378,6 +447,21 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
         return info;
     }
 
+    // See if our function apply site has an implicit isolated parameter. In
+    // such a case, we know that we have a caller inheriting isolated
+    // function. Return that this has disconnected isolation.
+    //
+    // DISCUSSION: The reason why we are doing this is that we already know that
+    // the AST is not going to label this as an isolation crossing point so we
+    // will only perform a merge. We want to just perform an isolation merge
+    // without adding additional isolation info. Otherwise, a nonisolated
+    // function that
+    if (auto paramInfo = fas.getSubstCalleeType()->maybeGetIsolatedParameter();
+        paramInfo && paramInfo->hasOption(SILParameterInfo::ImplicitLeading) &&
+        paramInfo->hasOption(SILParameterInfo::Isolated)) {
+      return SILIsolationInfo::getDisconnected(false /*unsafe nonisolated*/);
+    }
+
     if (auto *isolatedOp = fas.getIsolatedArgumentOperandOrNullPtr()) {
       // First look through ActorInstance agnostic values so we can find the
       // type of the actual underlying actor (e.x.: copy_value,
@@ -415,6 +499,12 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
           return SILIsolationInfo::getGlobalActorIsolated(SILValue(), selfASTType);
         }
 
+        if (auto *fArg = dyn_cast<SILFunctionArgument>(actualIsolatedValue)) {
+          if (auto info =
+                  SILIsolationInfo::getActorInstanceIsolated(fArg, fArg))
+            return info;
+        }
+
         // TODO: We really should be doing this based off of an Operand. Then
         // we would get the SILValue() for the first element. Today this can
         // only mess up isolation history.
@@ -430,12 +520,23 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
   }
 
   if (auto *pai = dyn_cast<PartialApplyInst>(inst)) {
+    // Check if we have any captures and if the isolation info for all captures
+    // are nonisolated(unsafe) or Sendable. In such a case, we consider the
+    // partial_apply to be nonisolated(unsafe). We purposely do not do this if
+    // the partial_apply does not have any parameters just out of paranoia... we
+    // shouldn't have such a partial_apply emitted by SILGen (it should use a
+    // thin to thick function or something like that)... but in that case since
+    // we do not have any nonisolated(unsafe), it doesn't make sense to
+    // propagate nonisolated(unsafe).
+    bool partialApplyIsNonIsolatedUnsafe = isPartialApplyNonisolatedUnsafe(pai);
+
     if (auto *ace = pai->getLoc().getAsASTNode<AbstractClosureExpr>()) {
       auto actorIsolation = ace->getActorIsolation();
 
       if (actorIsolation.isGlobalActor()) {
         return SILIsolationInfo::getGlobalActorIsolated(
-            pai, actorIsolation.getGlobalActor());
+                   pai, actorIsolation.getGlobalActor())
+            .withUnsafeNonIsolated(partialApplyIsNonIsolatedUnsafe);
       }
 
       if (actorIsolation.isActorInstanceIsolated()) {
@@ -449,9 +550,25 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
           }
         }
 
+        // Ok, we found an actor instance. Look for our actual isolated value.
         if (actorInstance) {
+          if (auto actualIsolatedValue =
+                  ActorInstance::getForValue(actorInstance)) {
+            // See if we have a function parameter. In such a case, we need to
+            // use the right parameter and the var decl.
+            if (auto *fArg = dyn_cast<SILFunctionArgument>(
+                    actualIsolatedValue.getValue())) {
+              if (auto info =
+                      SILIsolationInfo::getActorInstanceIsolated(pai, fArg)
+                          .withUnsafeNonIsolated(
+                              partialApplyIsNonIsolatedUnsafe))
+                return info;
+            }
+          }
+
           return SILIsolationInfo::getActorInstanceIsolated(
-              pai, actorInstance, actorIsolation.getActor());
+                     pai, actorInstance, actorIsolation.getActor())
+              .withUnsafeNonIsolated(partialApplyIsNonIsolatedUnsafe);
         }
 
         // For now, if we do not have an actor instance, just create an actor
@@ -465,12 +582,16 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
         //
         // TODO: How do we want to resolve this.
         return SILIsolationInfo::getPartialApplyActorInstanceIsolated(
-            pai, actorIsolation.getActor());
+                   pai, actorIsolation.getActor())
+            .withUnsafeNonIsolated(partialApplyIsNonIsolatedUnsafe);
       }
 
       assert(actorIsolation.getKind() != ActorIsolation::Erased &&
              "Implement this!");
     }
+
+    if (partialApplyIsNonIsolatedUnsafe)
+      return SILIsolationInfo::getDisconnected(partialApplyIsNonIsolatedUnsafe);
   }
 
   // See if the memory base is a ref_element_addr from an address. If so, add
@@ -480,6 +601,14 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
   if (auto *rei = dyn_cast<RefElementAddrInst>(inst)) {
     auto varIsolation = swift::getActorIsolation(rei->getField());
 
+    if (auto instance = ActorInstance::getForValue(rei->getOperand())) {
+      if (auto *fArg = llvm::dyn_cast_or_null<SILFunctionArgument>(
+              instance.maybeGetValue())) {
+        if (auto info = SILIsolationInfo::getActorInstanceIsolated(rei, fArg))
+          return info.withUnsafeNonIsolated(varIsolation.isNonisolatedUnsafe());
+      }
+    }
+
     auto *nomDecl =
         rei->getOperand()->getType().getNominalOrBoundGenericNominal();
 
@@ -680,7 +809,7 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
     }
   }
 
-  // See if we have a struct_extract from a global actor isolated type.
+  // See if we have a struct_extract from a global-actor-isolated type.
   if (auto *sei = dyn_cast<StructExtractInst>(inst)) {
     auto varIsolation = swift::getActorIsolation(sei->getField());
     if (auto isolation =
@@ -701,12 +830,12 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
         varIsolation.isNonisolatedUnsafe());
   }
 
-  // See if we have an unchecked_enum_data from a global actor isolated type.
+  // See if we have an unchecked_enum_data from a global-actor-isolated type.
   if (auto *uedi = dyn_cast<UncheckedEnumDataInst>(inst)) {
     return SILIsolationInfo::getGlobalActorIsolated(uedi, uedi->getEnumDecl());
   }
 
-  // See if we have an unchecked_enum_data from a global actor isolated type.
+  // See if we have an unchecked_enum_data from a global-actor-isolated type.
   if (auto *utedi = dyn_cast<UncheckedTakeEnumDataAddrInst>(inst)) {
     return SILIsolationInfo::getGlobalActorIsolated(utedi,
                                                     utedi->getEnumDecl());
@@ -726,7 +855,7 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
     }
   }
 
-  // See if we have a convert function from a Sendable actor isolated function,
+  // See if we have a convert function from a Sendable actor-isolated function,
   // we want to treat the result of the convert function as being actor isolated
   // so that we cannot escape the value.
   //
@@ -809,6 +938,12 @@ SILIsolationInfo SILIsolationInfo::get(SILInstruction *inst) {
   /// Consider non-Sendable metatypes to be task-isolated, so they cannot cross
   /// into another isolation domain.
   if (auto *mi = dyn_cast<MetatypeInst>(inst)) {
+    if (auto funcIsolation = mi->getFunction()->getActorIsolation();
+        funcIsolation && funcIsolation->isCallerIsolationInheriting()) {
+      return SILIsolationInfo::getTaskIsolated(mi)
+          .withNonisolatedNonsendingTaskIsolated(true);
+    }
+
     return SILIsolationInfo::getTaskIsolated(mi);
   }
 
@@ -837,7 +972,7 @@ SILIsolationInfo SILIsolationInfo::get(SILArgument *arg) {
   if (!SILIsolationInfo::isNonSendableType(arg->getType(), arg->getFunction()))
     return {};
 
-  // Handle a switch_enum from a global actor isolated type.
+  // Handle a switch_enum from a global-actor-isolated type.
   if (auto *phiArg = dyn_cast<SILPhiArgument>(arg)) {
     if (auto *singleTerm = phiArg->getSingleTerminator()) {
       if (auto *swi = dyn_cast<SwitchEnumInst>(singleTerm)) {
@@ -868,11 +1003,19 @@ SILIsolationInfo SILIsolationInfo::get(SILArgument *arg) {
 
   // Before we do anything further, see if we have an isolated parameter. This
   // handles isolated self and specifically marked isolated.
-  if (auto *isolatedArg = fArg->getFunction()->maybeGetIsolatedArgument()) {
+  if (auto *isolatedArg = llvm::cast_or_null<SILFunctionArgument>(
+          fArg->getFunction()->maybeGetIsolatedArgument())) {
+    // See if the function is nonisolated(nonsending). In such a case, return
+    // task isolated.
+    if (auto funcIsolation = fArg->getFunction()->getActorIsolation();
+        funcIsolation && funcIsolation->isCallerIsolationInheriting()) {
+      return SILIsolationInfo::getTaskIsolated(fArg)
+          .withNonisolatedNonsendingTaskIsolated(true);
+    }
+
     auto astType = isolatedArg->getType().getASTType();
-    if (auto *nomDecl = astType->lookThroughAllOptionalTypes()->getAnyActor()) {
-      return SILIsolationInfo::getActorInstanceIsolated(fArg, isolatedArg,
-                                                        nomDecl);
+    if (astType->lookThroughAllOptionalTypes()->getAnyActor()) {
+      return SILIsolationInfo::getActorInstanceIsolated(fArg, isolatedArg);
     }
   }
 
@@ -885,7 +1028,7 @@ SILIsolationInfo SILIsolationInfo::get(SILArgument *arg) {
     // disconnected so we can construct the actor value. Users cannot write
     // allocator functions so we just need to worry about compiler generated
     // code. In the case of a non-actor, we can only have an allocator that is
-    // global actor isolated, so we will never hit this code path.
+    // global-actor isolated, so we will never hit this code path.
     if (declRef.kind == SILDeclRef::Kind::Allocator) {
       if (auto isolation = fArg->getFunction()->getActorIsolation()) {
         if (isolation->isActorInstanceIsolated()) {
@@ -931,7 +1074,150 @@ SILIsolationInfo SILIsolationInfo::get(SILArgument *arg) {
   return SILIsolationInfo::getTaskIsolated(fArg);
 }
 
+/// Infer isolation region from the set of protocol conformances.
+SILIsolationInfo SILIsolationInfo::getFromConformances(
+    SILValue value, ArrayRef<ProtocolConformanceRef> conformances) {
+  for (auto conformance: conformances) {
+    if (conformance.getProtocol()->isMarkerProtocol())
+      continue;
+
+    // If the conformance is a pack, recurse.
+    if (conformance.isPack()) {
+      auto pack = conformance.getPack();
+      for (auto innerConformance : pack->getPatternConformances()) {
+        auto isolation = getFromConformances(value, innerConformance);
+        if (isolation)
+          return isolation;
+      }
+
+      continue;
+    }
+
+    // If a concrete conformance is global-actor-isolated, then the resulting
+    // value must be.
+    if (conformance.isConcrete()) {
+      auto isolation = conformance.getConcrete()->getIsolation();
+      if (isolation.isGlobalActor()) {
+        return SILIsolationInfo::getGlobalActorIsolated(
+            value, isolation.getGlobalActor(), conformance.getProtocol());
+      }
+
+      continue;
+    }
+
+    // If an abstract conformance is for a non-SendableMetatype-conforming
+    // type, the resulting value is task-isolated.
+    if (conformance.isAbstract()) {
+      auto sendableMetatype =
+        conformance.getType()->getASTContext()
+          .getProtocol(KnownProtocolKind::SendableMetatype);
+      if (sendableMetatype &&
+          lookupConformance(conformance.getType(), sendableMetatype,
+                            /*allowMissing=*/false).isInvalid()) {
+        return SILIsolationInfo::getTaskIsolated(value,
+                                                 conformance.getProtocol());
+      }
+    }
+  }
+
+  return {};
+}
+
+SILIsolationInfo SILIsolationInfo::getForCastConformances(
+    SILValue value, CanType sourceType, CanType destType) {
+  // If the enclosing function is @concurrent, then a cast cannot pick up
+  // any isolated conformances because it's not on any actor.
+  auto function = value->getFunction();
+  auto functionIsolation = function->getActorIsolation();
+  if (functionIsolation && functionIsolation->isNonisolated())
+    return {};
+
+  auto sendableMetatype =
+    sourceType->getASTContext().getProtocol(KnownProtocolKind::SendableMetatype);
+  if (!sendableMetatype)
+    return {};
+
+  if (!destType.isAnyExistentialType())
+    return {};
+
+  const auto &destLayout = destType.getExistentialLayout();
+  for (auto proto : destLayout.getProtocols()) {
+    if (proto->isMarkerProtocol())
+      continue;
+
+    // If the source type already conforms to the protocol, we won't be looking
+    // it up dynamically.
+    if (!lookupConformance(sourceType, proto, /*allowMissing=*/false).isInvalid())
+      continue;
+
+    // If the protocol inherits SendableMetatype, it can't have isolated
+    // conformances.
+    if (proto->inheritsFrom(sendableMetatype))
+      continue;
+
+    // The cast can produce a conformance with the same isolation as this
+    // function is dynamically executing. If that's known (i.e., because we're
+    // on a global actor), the value is isolated to that global actor.
+    // Otherwise, it's task-isolated.
+    if (functionIsolation && functionIsolation->isGlobalActor()) {
+      return SILIsolationInfo::getGlobalActorIsolated(
+          value, functionIsolation->getGlobalActor(), proto);
+    }
+
+    // Consider the cast to be task-isolated, because the runtime could find
+    // a conformance that is isolated to the current context.
+    return SILIsolationInfo::getTaskIsolated(value, proto);
+  }
+
+  return {};
+}
+
+/// Retrieve a suitable destination value for the cast instruction.
+///
+/// TODO: This should probably be SILDynamicCastInst::getDest(), but that has
+/// unimplemented TODOs.
+static SILValue destValueForDynamicCast(SILDynamicCastInst dynCast) {
+  auto inst = dynCast.getInstruction();
+  switch (dynCast.getKind()) {
+    case SILDynamicCastKind::CheckedCastAddrBranchInst:
+      return cast<CheckedCastAddrBranchInst>(inst)->getDest();
+    case SILDynamicCastKind::CheckedCastBranchInst:
+      return cast<CheckedCastBranchInst>(inst)->getSuccessBB()->getArgument(0);
+    case SILDynamicCastKind::UnconditionalCheckedCastAddrInst:
+      return cast<UnconditionalCheckedCastAddrInst>(inst)->getDest();
+    case SILDynamicCastKind::UnconditionalCheckedCastInst:
+      return cast<UnconditionalCheckedCastInst>(inst);
+  }
+}
+
+SILIsolationInfo SILIsolationInfo::getConformanceIsolation(SILInstruction *inst) {
+  // Existential initialization.
+  if (auto ieai = dyn_cast<InitExistentialAddrInst>(inst)) {
+    return getFromConformances(ieai, ieai->getConformances());
+  }
+  if (auto ieri = dyn_cast<InitExistentialRefInst>(inst)) {
+    return getFromConformances(ieri, ieri->getConformances());
+  }
+  if (auto ievi = dyn_cast<InitExistentialValueInst>(inst)) {
+    return getFromConformances(ievi, ievi->getConformances());
+  }
+
+  // Dynamic casts.
+  if (auto dynCast = SILDynamicCastInst::getAs(inst)) {
+    return getForCastConformances(
+        destValueForDynamicCast(dynCast),
+        dynCast.getSourceFormalType(),
+        dynCast.getTargetFormalType());
+  }
+
+  return {};
+}
+
 void SILIsolationInfo::printOptions(llvm::raw_ostream &os) const {
+  if (isolatedConformance) {
+    os << "isolated-conformance-to(" << isolatedConformance->getName() << ")";
+  }
+
   auto opts = getOptions();
   if (!opts)
     return;
@@ -958,7 +1244,41 @@ void SILIsolationInfo::printOptions(llvm::raw_ostream &os) const {
   llvm::interleave(data, os, ", ");
 }
 
-void SILIsolationInfo::print(llvm::raw_ostream &os) const {
+StringRef SILIsolationInfo::printActorIsolationForDiagnostics(
+    SILFunction *fn, ActorIsolation iso, StringRef openingQuotationMark,
+    bool asNoun) {
+  SmallString<64> string;
+  {
+    llvm::raw_svector_ostream os(string);
+    printActorIsolationForDiagnostics(fn, iso, os, openingQuotationMark,
+                                      asNoun);
+  }
+
+  return fn->getASTContext().getIdentifier(string).str();
+}
+
+void SILIsolationInfo::printActorIsolationForDiagnostics(
+    SILFunction *fn, ActorIsolation iso, llvm::raw_ostream &os,
+    StringRef openingQuotationMark, bool asNoun) {
+  // If we have NonisolatedNonsendingByDefault enabled, we need to return
+  // @concurrent for nonisolated and nonisolated for caller isolation inherited.
+  if (fn->isAsync() && fn->getASTContext().LangOpts.hasFeature(
+                           Feature::NonisolatedNonsendingByDefault)) {
+    if (iso.isCallerIsolationInheriting()) {
+      os << "nonisolated";
+      return;
+    }
+
+    if (iso.isNonisolated()) {
+      os << "@concurrent";
+      return;
+    }
+  }
+
+  return iso.printForDiagnostics(os, openingQuotationMark, asNoun);
+}
+
+void SILIsolationInfo::print(SILFunction *fn, llvm::raw_ostream &os) const {
   switch (Kind(*this)) {
   case Unknown:
     os << "unknown";
@@ -1005,7 +1325,7 @@ void SILIsolationInfo::print(llvm::raw_ostream &os) const {
       }
     }
 
-    getActorIsolation().printForDiagnostics(os);
+    printActorIsolationForDiagnostics(fn, getActorIsolation(), os);
     printOptions(os);
     return;
   case Task:
@@ -1017,10 +1337,10 @@ void SILIsolationInfo::print(llvm::raw_ostream &os) const {
   }
 }
 
-bool SILIsolationInfo::hasSameIsolation(ActorIsolation actorIsolation) const {
+bool SILIsolationInfo::hasSameIsolation(ActorIsolation other) const {
   if (getKind() != Kind::Actor)
     return false;
-  return getActorIsolation() == actorIsolation;
+  return getActorIsolation() == other;
 }
 
 bool SILIsolationInfo::hasSameIsolation(const SILIsolationInfo &other) const {
@@ -1040,7 +1360,7 @@ bool SILIsolationInfo::hasSameIsolation(const SILIsolationInfo &other) const {
     // If either have an actor instance, and the actor instance doesn't match,
     // return false.
     //
-    // This ensures that cases like comparing two global actor isolated things
+    // This ensures that cases like comparing two global-actor-isolated things
     // do not hit this path.
     //
     // It also catches cases where we have a missing actor instance.
@@ -1076,21 +1396,35 @@ bool SILIsolationInfo::isEqual(const SILIsolationInfo &other) const {
 
 void SILIsolationInfo::Profile(llvm::FoldingSetNodeID &id) const {
   id.AddInteger(getKind());
+  id.AddInteger(getOptions().toRaw());
   switch (getKind()) {
   case Unknown:
   case Disconnected:
     return;
   case Task:
     id.AddPointer(getIsolatedValue());
+    id.AddPointer(getIsolatedConformance());
     return;
   case Actor:
     id.AddPointer(getIsolatedValue());
+    id.AddPointer(getIsolatedConformance());
     getActorIsolation().Profile(id);
     return;
   }
 }
 
-void SILIsolationInfo::printForDiagnostics(llvm::raw_ostream &os) const {
+StringRef SILIsolationInfo::printForDiagnostics(SILFunction *fn) const {
+  SmallString<64> string;
+  {
+    llvm::raw_svector_ostream os(string);
+    printForDiagnostics(fn, os);
+  }
+
+  return fn->getASTContext().getIdentifier(string).str();
+}
+
+void SILIsolationInfo::printForDiagnostics(SILFunction *fn,
+                                           llvm::raw_ostream &os) const {
   switch (Kind(*this)) {
   case Unknown:
     llvm::report_fatal_error("Printing unknown for diagnostics?!");
@@ -1125,15 +1459,41 @@ void SILIsolationInfo::printForDiagnostics(llvm::raw_ostream &os) const {
       }
     }
 
-    getActorIsolation().printForDiagnostics(os);
+    printActorIsolationForDiagnostics(fn, getActorIsolation(), os);
     return;
   case Task:
+    if (fn->isAsync() && fn->getASTContext().LangOpts.hasFeature(
+                             Feature::NonisolatedNonsendingByDefault)) {
+      if (isNonisolatedNonsendingTaskIsolated()) {
+        os << "task-isolated";
+        return;
+      }
+      os << "@concurrent task-isolated";
+      return;
+    }
+
+    if (isNonisolatedNonsendingTaskIsolated()) {
+      os << "nonisolated(nonsending) task-isolated";
+      return;
+    }
+
     os << "task-isolated";
     return;
   }
 }
 
-void SILIsolationInfo::printForCodeDiagnostic(llvm::raw_ostream &os) const {
+StringRef SILIsolationInfo::printForCodeDiagnostic(SILFunction *fn) const {
+  SmallString<64> string;
+  {
+    llvm::raw_svector_ostream os(string);
+    printForCodeDiagnostic(fn, os);
+  }
+
+  return fn->getASTContext().getIdentifier(string).str();
+}
+
+void SILIsolationInfo::printForCodeDiagnostic(SILFunction *fn,
+                                              llvm::raw_ostream &os) const {
   switch (Kind(*this)) {
   case Unknown:
     llvm::report_fatal_error("Printing unknown for code diagnostic?!");
@@ -1168,7 +1528,7 @@ void SILIsolationInfo::printForCodeDiagnostic(llvm::raw_ostream &os) const {
       }
     }
 
-    getActorIsolation().printForDiagnostics(os);
+    printActorIsolationForDiagnostics(fn, getActorIsolation(), os);
     os << " code";
     return;
   case Task:
@@ -1177,7 +1537,8 @@ void SILIsolationInfo::printForCodeDiagnostic(llvm::raw_ostream &os) const {
   }
 }
 
-void SILIsolationInfo::printForOneLineLogging(llvm::raw_ostream &os) const {
+void SILIsolationInfo::printForOneLineLogging(SILFunction *fn,
+                                              llvm::raw_ostream &os) const {
   switch (Kind(*this)) {
   case Unknown:
     os << "unknown";
@@ -1217,7 +1578,7 @@ void SILIsolationInfo::printForOneLineLogging(llvm::raw_ostream &os) const {
       }
     }
 
-    getActorIsolation().printForDiagnostics(os);
+    printActorIsolationForDiagnostics(fn, getActorIsolation(), os);
     printOptions(os);
     return;
   case Task:
@@ -1268,6 +1629,24 @@ bool SILIsolationInfo::isNonSendableType(SILType type, SILFunction *fn) {
   return *behavior != DiagnosticBehavior::Ignore;
 }
 
+SILIsolationInfo SILIsolationInfo::getFunctionIsolation(SILFunction *fn) {
+  auto isolation = fn->getActorIsolation();
+  if (!isolation)
+    return {};
+
+  if (isolation->isGlobalActor()) {
+    return SILIsolationInfo::getGlobalActorIsolated(
+        SILValue(), isolation->getGlobalActor());
+  }
+
+  if (isolation->isActorInstanceIsolated()) {
+    return SILIsolationInfo::getActorInstanceIsolated(
+        SILValue(), cast<SILFunctionArgument>(fn->maybeGetIsolatedArgument()));
+  }
+
+  return {};
+}
+
 //===----------------------------------------------------------------------===//
 //                            MARK: ActorInstance
 //===----------------------------------------------------------------------===//
@@ -1308,6 +1687,30 @@ SILValue ActorInstance::lookThroughInsts(SILValue value) {
       }
     }
 
+    // See if this is distributed asLocalActor. In such a case, we want to
+    // consider the result actor to be the same actor as the input isolated
+    // parameter.
+    if (auto fas = FullApplySite::isa(svi)) {
+      if (auto *functionRef = fas.getReferencedFunctionOrNull()) {
+        if (auto declRef = functionRef->getDeclRef()) {
+          if (auto *accessor =
+                  dyn_cast_or_null<AccessorDecl>(declRef.getFuncDecl())) {
+            if (auto asLocalActorDecl =
+                    getDistributedActorAsLocalActorComputedProperty(
+                        functionRef->getDeclContext()->getParentModule())) {
+              if (auto asLocalActorGetter =
+                      asLocalActorDecl->getAccessor(AccessorKind::Get);
+                  asLocalActorGetter && asLocalActorGetter == accessor) {
+                value = lookThroughInsts(
+                    fas.getIsolatedArgumentOperandOrNullPtr()->get());
+                continue;
+              }
+            }
+          }
+        }
+      }
+    }
+
     break;
   }
 
@@ -1322,15 +1725,20 @@ std::optional<SILDynamicMergedIsolationInfo>
 SILDynamicMergedIsolationInfo::merge(SILIsolationInfo other) const {
   // If we are greater than the other kind, then we are further along the
   // lattice. We ignore the change.
-  if (unsigned(innerInfo.getKind() > unsigned(other.getKind())))
+  //
+  // NOTE: If we are further along, then we both cannot be task isolated. In
+  // such a case, we are the only potential thing that can be
+  // nonisolated(unsafe)... so we do not need to try to propagate.
+  if (unsigned(innerInfo.getKind() > unsigned(other.getKind()))) {
     return {*this};
+  }
 
   // If we are both actor isolated...
   if (innerInfo.isActorIsolated() && other.isActorIsolated()) {
     // If both innerInfo and other have the same isolation, we are obviously
     // done. Just return innerInfo since we could return either.
     if (innerInfo.hasSameIsolation(other))
-      return {innerInfo};
+      return {innerInfo.withMergedIsolatedConformance(other.getIsolatedConformance())};
 
     // Ok, there is some difference in between innerInfo and other. Lets see if
     // they are both actor instance isolated and if either are unapplied
@@ -1339,9 +1747,9 @@ SILDynamicMergedIsolationInfo::merge(SILIsolationInfo other) const {
     if (innerInfo.getActorIsolation().isActorInstanceIsolated() &&
         other.getActorIsolation().isActorInstanceIsolated()) {
       if (innerInfo.isUnappliedIsolatedAnyParameter())
-        return other;
+        return other.withMergedIsolatedConformance(innerInfo.getIsolatedConformance());
       if (other.isUnappliedIsolatedAnyParameter())
-        return innerInfo;
+        return innerInfo.withMergedIsolatedConformance(other.getIsolatedConformance());
     }
 
     // Otherwise, they do not match... so return None to signal merge failure.
@@ -1358,10 +1766,45 @@ SILDynamicMergedIsolationInfo::merge(SILIsolationInfo other) const {
     return {other.withUnsafeNonIsolated(false)};
   }
 
+  // We know that we are either the same as other or other is further along. If
+  // other is further along, it is the only thing that can propagate the task
+  // isolated bit. So we do not need to do anything. If we are equal though, we
+  // may need to propagate the bit. This ensures that when we emit a diagnostic
+  // we appropriately say potentially actor isolated code instead of code in the
+  // current task.
+  //
+  // TODO: We should really represent this as a separate isolation info
+  // kind... but that would be a larger change than we want for 6.2.
+  if (innerInfo.isTaskIsolated() && other.isTaskIsolated()) {
+    if (innerInfo.isNonisolatedNonsendingTaskIsolated() ||
+        other.isNonisolatedNonsendingTaskIsolated())
+      return other.withNonisolatedNonsendingTaskIsolated(true)
+        .withMergedIsolatedConformance(innerInfo.getIsolatedConformance());
+  }
+
   // Otherwise, just return other.
   return {other};
 }
 
+void ActorInstance::print(llvm::raw_ostream &os) const {
+  os << "Actor Instance. Kind: ";
+  switch (getKind()) {
+  case Kind::Value:
+    os << "Value.";
+    break;
+  case Kind::ActorAccessorInit:
+    os << "ActorAccessorInit.";
+    break;
+  case Kind::CapturedActorSelf:
+    os << "CapturedActorSelf.";
+    break;
+  }
+
+  if (auto value = maybeGetValue()) {
+    os << " Value: " << value;
+  };
+}
+
 //===----------------------------------------------------------------------===//
 //                                MARK: Tests
 //===----------------------------------------------------------------------===//
@@ -1381,7 +1824,8 @@ static FunctionTest
                                   SILIsolationInfo::get(value);
                               llvm::outs() << "Input Value: " << *value;
                               llvm::outs() << "Isolation: ";
-                              info.printForOneLineLogging(llvm::outs());
+                              info.printForOneLineLogging(&function,
+                                                          llvm::outs());
                               llvm::outs() << "\n";
                             });
 
@@ -1401,13 +1845,13 @@ static FunctionTest IsolationMergeTest(
       mergedInfo = mergedInfo->merge(secondValueInfo);
       llvm::outs() << "First Value: " << *firstValue;
       llvm::outs() << "First Isolation: ";
-      firstValueInfo.printForOneLineLogging(llvm::outs());
+      firstValueInfo.printForOneLineLogging(&function, llvm::outs());
       llvm::outs() << "\nSecond Value: " << *secondValue;
       llvm::outs() << "Second Isolation: ";
-      secondValueInfo.printForOneLineLogging(llvm::outs());
+      secondValueInfo.printForOneLineLogging(&function, llvm::outs());
       llvm::outs() << "\nMerged Isolation: ";
       if (mergedInfo) {
-        mergedInfo->printForOneLineLogging(llvm::outs());
+        mergedInfo->printForOneLineLogging(&function, llvm::outs());
       } else {
         llvm::outs() << "Merge failure!";
       }
diff --git a/lib/SILOptimizer/Utils/ShrinkBorrowScope.cpp b/lib/SILOptimizer/Utils/ShrinkBorrowScope.cpp
index da5909e5dcdb2..d7a6782bb6b84 100644
--- a/lib/SILOptimizer/Utils/ShrinkBorrowScope.cpp
+++ b/lib/SILOptimizer/Utils/ShrinkBorrowScope.cpp
@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 /// Shrink borrow scopes by hoisting end_borrows up to deinit barriers.  After
-/// this is done, CanonicalizeOSSALifetime is free to hoist the destroys of the
+/// this is done, OSSACanonicalizeOwned is free to hoist the destroys of the
 /// owned value up to the end_borrow.  In this way, the lexical lifetime of
 /// guaranteed values is preserved.
 //===----------------------------------------------------------------------===//
@@ -26,9 +26,9 @@
 #include "swift/SILOptimizer/Analysis/Reachability.h"
 #include "swift/SILOptimizer/Analysis/VisitBarrierAccessScopes.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
-#include "swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h"
 #include "swift/SILOptimizer/Utils/InstOptUtils.h"
 #include "swift/SILOptimizer/Utils/InstructionDeleter.h"
+#include "swift/SILOptimizer/Utils/OSSACanonicalizeGuaranteed.h"
 #include "llvm/ADT/STLExtras.h"
 
 #define DEBUG_TYPE "copy-propagation"
diff --git a/lib/SILOptimizer/Utils/SpecializationMangler.cpp b/lib/SILOptimizer/Utils/SpecializationMangler.cpp
index 1b444b978b1d9..7362d76482e0e 100644
--- a/lib/SILOptimizer/Utils/SpecializationMangler.cpp
+++ b/lib/SILOptimizer/Utils/SpecializationMangler.cpp
@@ -44,77 +44,71 @@ FunctionSignatureSpecializationMangler::FunctionSignatureSpecializationMangler(A
   for (unsigned i = 0, e = F->getConventions().getNumSILArguments(); i != e;
        ++i) {
     (void)i;
-    OrigArgs.push_back(
-        {ArgumentModifierIntBase(ArgumentModifier::Unmodified), nullptr});
+    OrigArgs.push_back(ArgumentModifier::Unmodified);
   }
   ReturnValue = ReturnValueModifierIntBase(ReturnValueModifier::Unmodified);
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentDead(
     unsigned OrigArgIdx) {
-  OrigArgs[OrigArgIdx].first |= ArgumentModifierIntBase(ArgumentModifier::Dead);
+  OrigArgs[OrigArgIdx].append(ArgumentModifier::Dead);
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentClosureProp(
-    unsigned OrigArgIdx, PartialApplyInst *PAI) {
+    unsigned OrigArgIdx, SILInstruction *closure) {
+  ASSERT(isa<PartialApplyInst>(closure) || isa<ThinToThickFunctionInst>(closure));
   auto &Info = OrigArgs[OrigArgIdx];
-  Info.first = ArgumentModifierIntBase(ArgumentModifier::ClosureProp);
-  Info.second = PAI;
+  Info.kind = ArgumentModifier::ClosureProp;
+  Info.inst = closure;
 }
 
-void FunctionSignatureSpecializationMangler::setArgumentClosureProp(
-    unsigned OrigArgIdx, ThinToThickFunctionInst *TTTFI) {
+void FunctionSignatureSpecializationMangler::setArgumentClosurePropPreviousArg(
+    unsigned OrigArgIdx, unsigned otherArgIdx) {
   auto &Info = OrigArgs[OrigArgIdx];
-  Info.first = ArgumentModifierIntBase(ArgumentModifier::ClosureProp);
-  Info.second = TTTFI;
+  Info.kind = ArgumentModifier::ClosurePropPreviousArg;
+  Info.otherArgIdx = otherArgIdx;
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentConstantProp(
     unsigned OrigArgIdx, SILInstruction *constInst) {
   auto &Info = OrigArgs[OrigArgIdx];
-  Info.first = ArgumentModifierIntBase(ArgumentModifier::ConstantProp);
-  Info.second = constInst;
+  Info.kind = ArgumentModifier::ConstantProp;
+  Info.inst = constInst;
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentOwnedToGuaranteed(
     unsigned OrigArgIdx) {
-  OrigArgs[OrigArgIdx].first |=
-      ArgumentModifierIntBase(ArgumentModifier::OwnedToGuaranteed);
+  OrigArgs[OrigArgIdx].append(ArgumentModifier::OwnedToGuaranteed);
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentSROA(
     unsigned OrigArgIdx) {
-  OrigArgs[OrigArgIdx].first |= ArgumentModifierIntBase(ArgumentModifier::SROA);
+  OrigArgs[OrigArgIdx].append(ArgumentModifier::SROA);
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentGuaranteedToOwned(
     unsigned OrigArgIdx) {
-  OrigArgs[OrigArgIdx].first |=
-      ArgumentModifierIntBase(ArgumentModifier::GuaranteedToOwned);
+  OrigArgs[OrigArgIdx].append(ArgumentModifier::GuaranteedToOwned);
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentExistentialToGeneric(
     unsigned OrigArgIdx) {
-  OrigArgs[OrigArgIdx].first |=
-      ArgumentModifierIntBase(ArgumentModifier::ExistentialToGeneric);
+  OrigArgs[OrigArgIdx].append(ArgumentModifier::ExistentialToGeneric);
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentBoxToValue(
     unsigned OrigArgIdx) {
-  OrigArgs[OrigArgIdx].first =
-      ArgumentModifierIntBase(ArgumentModifier::BoxToValue);
+  OrigArgs[OrigArgIdx].kind = ArgumentModifier::BoxToValue;
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentBoxToStack(
     unsigned OrigArgIdx) {
-  OrigArgs[OrigArgIdx].first =
-      ArgumentModifierIntBase(ArgumentModifier::BoxToStack);
+  OrigArgs[OrigArgIdx].kind = ArgumentModifier::BoxToStack;
 }
 
 void FunctionSignatureSpecializationMangler::setArgumentInOutToOut(
     unsigned OrigArgIdx) {
-  OrigArgs[OrigArgIdx].first =
-      ArgumentModifierIntBase(ArgumentModifier::InOutToOut);
+  OrigArgs[OrigArgIdx].kind = ArgumentModifier::InOutToOut;
 }
 
 void
@@ -130,15 +124,33 @@ setRemovedEffect(EffectKind effect) {
   RemovedEffects |= effect;
 }
 
+static APInt makeUnsigned(APInt i) {
+  if (i.isNegative()) {
+    return i.zext(i.getBitWidth() + 1);
+  }
+  return i;
+}
+
 void
 FunctionSignatureSpecializationMangler::mangleConstantProp(SILInstruction *constInst) {
-  // Append the prefix for constant propagation 'p'.
-  ArgOpBuffer << 'p';
-
-  // Then append the unique identifier of our literal.
   switch (constInst->getKind()) {
   default:
     llvm_unreachable("unknown literal");
+  case SILInstructionKind::StructInst: {
+    auto *si = cast<StructInst>(constInst);
+    ArgOpBuffer << 'S';
+    appendType(si->getType().getASTType(), nullptr);
+    for (SILValue op : si->getOperandValues()) {
+      mangleConstantProp(cast<SingleValueInstruction>(op));
+    }
+    break;
+  }
+  case SILInstructionKind::ThinToThickFunctionInst:
+  case SILInstructionKind::ConvertFunctionInst:
+  case SILInstructionKind::UpcastInst:
+  case SILInstructionKind::OpenExistentialRefInst:
+    mangleConstantProp(cast<SingleValueInstruction>(constInst->getOperand(0)));
+    break;
   case SILInstructionKind::PreviousDynamicFunctionRefInst:
   case SILInstructionKind::DynamicFunctionRefInst:
   case SILInstructionKind::FunctionRefInst: {
@@ -156,25 +168,28 @@ FunctionSignatureSpecializationMangler::mangleConstantProp(SILInstruction *const
   }
   case SILInstructionKind::IntegerLiteralInst: {
     APInt apint = cast<IntegerLiteralInst>(constInst)->getValue();
-    ArgOpBuffer << 'i' << apint;
+    ArgOpBuffer << 'i' << makeUnsigned(apint);
     break;
   }
   case SILInstructionKind::FloatLiteralInst: {
     APInt apint = cast<FloatLiteralInst>(constInst)->getBits();
-    ArgOpBuffer << 'd' << apint;
+    ArgOpBuffer << 'd' << makeUnsigned(apint);
     break;
   }
   case SILInstructionKind::StringLiteralInst: {
     StringLiteralInst *SLI = cast<StringLiteralInst>(constInst);
     StringRef V = SLI->getValue();
-    assert(V.size() <= 32 && "Cannot encode string of length > 32");
-    std::string VBuffer;
-    if (!V.empty() && (isDigit(V[0]) || V[0] == '_')) {
-      VBuffer = "_";
-      VBuffer.append(V.data(), V.size());
-      V = VBuffer;
+    if (V.size() > 32) {
+      MD5Stream md5Stream;
+      md5Stream << V;
+      llvm::MD5::MD5Result md5Hash;
+      md5Stream.final(md5Hash);
+      SmallString<32> resultStr;
+      llvm::MD5::stringifyResult(md5Hash, resultStr);
+      appendStringAsIdentifier(resultStr);
+    } else {
+      appendStringAsIdentifier(V);
     }
-    appendIdentifier(V);
 
     ArgOpBuffer << 's';
     switch (SLI->getEncoding()) {
@@ -249,39 +264,44 @@ FunctionSignatureSpecializationMangler::mangleClosureProp(SILInstruction *Inst)
   }
 }
 
-void FunctionSignatureSpecializationMangler::mangleArgument(
-    ArgumentModifierIntBase ArgMod, NullablePtr<SILInstruction> Inst) {
-  if (ArgMod == ArgumentModifierIntBase(ArgumentModifier::ConstantProp)) {
-    mangleConstantProp(Inst.get());
+void FunctionSignatureSpecializationMangler::mangleArgument(ArgInfo argInfo) {
+  switch (argInfo.kind) {
+  case ArgumentModifier::ConstantProp:
+    // Append the prefix for constant propagation 'p'.
+    ArgOpBuffer << 'p';
+    mangleConstantProp(argInfo.inst);
     return;
-  }
 
-  if (ArgMod == ArgumentModifierIntBase(ArgumentModifier::ClosureProp)) {
-    mangleClosureProp(Inst.get());
+  case ArgumentModifier::ClosureProp:
+    mangleClosureProp(argInfo.inst);
     return;
-  }
 
-  if (ArgMod == ArgumentModifierIntBase(ArgumentModifier::Unmodified)) {
+  case ArgumentModifier::Unmodified:
     ArgOpBuffer << 'n';
     return;
-  }
 
-  if (ArgMod == ArgumentModifierIntBase(ArgumentModifier::BoxToValue)) {
+  case ArgumentModifier::BoxToValue:
     ArgOpBuffer << 'i';
     return;
-  }
 
-  if (ArgMod == ArgumentModifierIntBase(ArgumentModifier::BoxToStack)) {
+  case ArgumentModifier::BoxToStack:
     ArgOpBuffer << 's';
     return;
-  }
 
-  if (ArgMod == ArgumentModifierIntBase(ArgumentModifier::InOutToOut)) {
+  case ArgumentModifier::InOutToOut:
     ArgOpBuffer << 'r';
     return;
+
+  case ArgumentModifier::ClosurePropPreviousArg:
+    ArgOpBuffer << 'C' << argInfo.otherArgIdx;
+    return;
+
+  default:
+    break;
   }
 
   bool hasSomeMod = false;
+  ArgumentModifierIntBase ArgMod = ArgumentModifierIntBase(argInfo.kind);
   if (ArgMod & ArgumentModifierIntBase(ArgumentModifier::ExistentialToGeneric)) {
     ArgOpBuffer << 'e';
     hasSomeMod = true;
@@ -333,10 +353,7 @@ std::string FunctionSignatureSpecializationMangler::mangle() {
   beginMangling();
 
   for (unsigned i : indices(OrigArgs)) {
-    ArgumentModifierIntBase ArgMod;
-    NullablePtr<SILInstruction> Inst;
-    std::tie(ArgMod, Inst) = OrigArgs[i];
-    mangleArgument(ArgMod, Inst);
+    mangleArgument(OrigArgs[i]);
   }
   ArgOpBuffer << '_';
   mangleReturnValue(ReturnValue);
diff --git a/lib/SILOptimizer/Utils/ValueLifetime.cpp b/lib/SILOptimizer/Utils/ValueLifetime.cpp
index ab3d510b583b4..0485407415ca5 100644
--- a/lib/SILOptimizer/Utils/ValueLifetime.cpp
+++ b/lib/SILOptimizer/Utils/ValueLifetime.cpp
@@ -45,10 +45,10 @@ void ValueLifetimeBoundary::visitInsertionPoints(
 }
 
 void ValueLifetimeAnalysis::propagateLiveness() {
-  bool defIsInstruction = defValue.is<SILInstruction *>();
+  bool defIsInstruction = isa<SILInstruction *>(defValue);
   assert(liveBlocks.empty() && "frontier computed twice");
   assert(
-      (!defIsInstruction || !userSet.count(defValue.get<SILInstruction *>())) &&
+      (!defIsInstruction || !userSet.count(cast<SILInstruction *>(defValue))) &&
       "definition cannot be its own use");
 
   // Compute the def block only if we have a SILInstruction. If we have a
@@ -69,13 +69,13 @@ void ValueLifetimeAnalysis::propagateLiveness() {
     if (defIsInstruction && userBlock == defBB)
       ++numUsersBeforeDef;
   }
-  assert((defValue.is<SILInstruction *>() || (numUsersBeforeDef == 0)) &&
+  assert((isa<SILInstruction *>(defValue) || (numUsersBeforeDef == 0)) &&
          "Non SILInstruction defValue with users before the def?!");
 
   // Don't count any users in the defBB which are actually located _after_ the
   // defValue.
   if (defIsInstruction) {
-    auto instIter = defValue.get<SILInstruction *>()->getIterator();
+    auto instIter = cast<SILInstruction *>(defValue)->getIterator();
     while (numUsersBeforeDef > 0 && ++instIter != defBB->end()) {
       if (userSet.count(&*instIter))
         --numUsersBeforeDef;
@@ -143,7 +143,7 @@ void ValueLifetimeAnalysis::computeLifetime(
           //
           // This should never happen if we have a SILArgument since the
           // SILArgument can not have any uses before it in a block.
-          assert(defValue.is<SILInstruction *>() &&
+          assert(isa<SILInstruction *>(defValue) &&
                  "SILArguments dominate all instructions in their defining "
                  "blocks");
           usedAndRedefinedInSucc = true;
@@ -154,7 +154,7 @@ void ValueLifetimeAnalysis::computeLifetime(
       // Here, the basic block bb uses the value and later redefines the value.
       // Therefore, this value's lifetime ends after its last use preceding the
       // re-definition of the value.
-      auto ii = defValue.get<SILInstruction *>()->getReverseIterator();
+      auto ii = cast<SILInstruction *>(defValue)->getReverseIterator();
       for (; ii != bb->rend(); ++ii) {
         if (userSet.count(&*ii)) {
           visitLastUser(&*ii);
@@ -393,7 +393,7 @@ void ValueLifetimeAnalysis::dump() const {
   if (auto *ii = defValue.dyn_cast<SILInstruction *>()) {
     llvm::errs() << *ii;
   } else {
-    llvm::errs() << *defValue.get<SILArgument *>();
+    llvm::errs() << *cast<SILArgument *>(defValue);
   }
   for (SILInstruction *use : userSet) {
     llvm::errs() << "  use: " << *use;
diff --git a/lib/SILOptimizer/Utils/VariableNameUtils.cpp b/lib/SILOptimizer/Utils/VariableNameUtils.cpp
index 34fac736c4bf5..2273f67f8c590 100644
--- a/lib/SILOptimizer/Utils/VariableNameUtils.cpp
+++ b/lib/SILOptimizer/Utils/VariableNameUtils.cpp
@@ -599,6 +599,17 @@ SILValue VariableNameInferrer::findDebugInfoProvidingValueHelper(
       }
     }
 
+    // Borrow/mutate accessor
+    if (searchValue->isBorrowAccessorResult()) {
+      if (auto fas =
+              FullApplySite::isa(searchValue->getDefiningInstruction())) {
+        if (auto selfParam = getNamePathComponentFromCallee(fas)) {
+          searchValue = selfParam;
+          continue;
+        }
+      }
+    }
+
     // Addressor accessor.
     if (auto ptrToAddr =
             dyn_cast<PointerToAddressInst>(stripAccessMarkers(searchValue))) {
diff --git a/lib/Sema/AssociatedTypeInference.cpp b/lib/Sema/AssociatedTypeInference.cpp
index b72d80649b53c..665b8af1178b4 100644
--- a/lib/Sema/AssociatedTypeInference.cpp
+++ b/lib/Sema/AssociatedTypeInference.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -30,12 +30,13 @@
 //   a global conformance lookup.
 //
 //===----------------------------------------------------------------------===//
-#include "TypeCheckProtocol.h"
-#include "DerivedConformances.h"
+
+#include "DerivedConformance/DerivedConformance.h"
 #include "TypeAccessScopeChecker.h"
-#include "TypeChecker.h"
 #include "TypeCheckAvailability.h"
+#include "TypeCheckProtocol.h"
 #include "TypeCheckType.h"
+#include "TypeChecker.h"
 
 #include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/ConformanceLookup.h"
@@ -438,6 +439,28 @@ static bool isAsyncSequenceFailure(AssociatedTypeDecl *assocType) {
   return assocType->getName() == assocType->getASTContext().Id_Failure;
 }
 
+static Type resolveTypeWitnessViaParameterizedProtocol(
+    Type t, AssociatedTypeDecl *assocType) {
+  if (auto *pct = t->getAs<ProtocolCompositionType>()) {
+    for (auto member : pct->getMembers()) {
+      if (auto result = resolveTypeWitnessViaParameterizedProtocol(
+            member, assocType)) {
+        return result;
+      }
+    }
+  } else if (auto *ppt = t->getAs<ParameterizedProtocolType>()) {
+    auto *proto = ppt->getProtocol();
+    unsigned i = 0;
+    for (auto *otherAssocType : proto->getPrimaryAssociatedTypes()) {
+      if (otherAssocType->getName() == assocType->getName())
+        return ppt->getArgs()[i];
+      ++i;
+    }
+  }
+
+  return Type();
+}
+
 /// Attempt to resolve a type witness via member name lookup.
 static ResolveWitnessResult resolveTypeWitnessViaLookup(
                        NormalProtocolConformance *conformance,
@@ -448,12 +471,30 @@ static ResolveWitnessResult resolveTypeWitnessViaLookup(
   // Conformances constructed by the ClangImporter should have explicit type
   // witnesses already.
   if (isa<ClangModuleUnit>(dc->getModuleScopeContext())) {
-    llvm::errs() << "Cannot look up associated type for imported conformance:\n";
-    conformance->getType().dump(llvm::errs());
-    assocType->dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Cannot look up associated type for imported conformance:\n";
+      conformance->getType().dump(out);
+      assocType->dump(out);
+    });
   }
 
+  // Look for a parameterized protocol type in the conformance context's
+  // inheritance clause.
+  bool deducedFromParameterizedProtocolType = false;
+  auto inherited = (isa<NominalTypeDecl>(dc)
+                    ? cast<NominalTypeDecl>(dc)->getInherited()
+                    : cast<ExtensionDecl>(dc)->getInherited());
+  for (auto index : inherited.getIndices()) {
+    if (auto inheritedTy = inherited.getResolvedType(index)) {
+      if (auto typeWitness = resolveTypeWitnessViaParameterizedProtocol(
+            inheritedTy, assocType)) {
+        recordTypeWitness(conformance, assocType, typeWitness, nullptr);
+        deducedFromParameterizedProtocolType = true;
+      }
+    }
+  }
+
+  // Next, look for a member type declaration with this name.
   NLOptions subOptions = (NL_QualifiedDefault | NL_OnlyTypes |
                           NL_ProtocolMembers | NL_IncludeAttributeImplements);
 
@@ -560,27 +601,40 @@ static ResolveWitnessResult resolveTypeWitnessViaLookup(
     }
   }
 
-  // If there are no viable witnesses, and all nonviable candidates came from
-  // protocol extensions, treat this as "missing".
-  if (viable.empty() &&
-      std::find_if(nonViable.begin(), nonViable.end(),
-                   [](const std::pair<TypeDecl *, CheckTypeWitnessResult> &x) {
-                     return x.first->getDeclContext()
-                        ->getSelfProtocolDecl() == nullptr;
-                   }) == nonViable.end())
-    return ResolveWitnessResult::Missing;
+  if (!deducedFromParameterizedProtocolType) {
+    // If there are no viable witnesses, and all nonviable candidates came from
+    // protocol extensions, treat this as "missing".
+    if (viable.empty() &&
+        std::find_if(nonViable.begin(), nonViable.end(),
+                     [](const std::pair<TypeDecl *, CheckTypeWitnessResult> &x) {
+                       return x.first->getDeclContext()
+                          ->getSelfProtocolDecl() == nullptr;
+                     }) == nonViable.end())
+      return ResolveWitnessResult::Missing;
+
+    // If there is a single viable candidate, form a substitution for it.
+    if (viable.size() == 1) {
+      auto interfaceType = viable.front().MemberType;
+      recordTypeWitness(conformance, assocType, interfaceType,
+                        viable.front().Member);
+      return ResolveWitnessResult::Success;
+    }
 
-  // If there is a single viable candidate, form a substitution for it.
-  if (viable.size() == 1) {
-    auto interfaceType = viable.front().MemberType;
-    recordTypeWitness(conformance, assocType, interfaceType,
-                      viable.front().Member);
-    return ResolveWitnessResult::Success;
-  }
+    // Record an error.
+    recordTypeWitness(conformance, assocType,
+                      ErrorType::get(ctx), nullptr);
+  } else {
+    // We deduced the type witness from a parameterized protocol type, so just
+    // make sure there was nothing else.
+    if (viable.size() == 1 &&
+        isa<TypeAliasDecl>(viable[0].Member) &&
+        viable[0].Member->isSynthesized()) {
+      // We found the type alias synthesized above.
+      return ResolveWitnessResult::Success;
+    }
 
-  // Record an error.
-  recordTypeWitness(conformance, assocType,
-                    ErrorType::get(ctx), nullptr);
+    // Otherwise fall through.
+  }
 
   // If we had multiple viable types, diagnose the ambiguity.
   if (!viable.empty()) {
@@ -1607,11 +1661,12 @@ AssociatedTypeInference::getPotentialTypeWitnessesFromRequirement(
   // Conformances constructed by the ClangImporter should have explicit type
   // witnesses already.
   if (isa<ClangModuleUnit>(conformance->getDeclContext()->getModuleScopeContext())) {
-    llvm::errs() << "Cannot infer associated types for imported conformance:\n";
-    conformance->getType().dump(llvm::errs());
-    for (auto assocTypeDecl : allUnresolved)
-      assocTypeDecl->dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Cannot infer associated types for imported conformance:\n";
+      conformance->getType().dump(out);
+      for (auto assocTypeDecl : allUnresolved)
+        assocTypeDecl->dump(out);
+    });
   }
 
   TypeReprCycleCheckWalker cycleCheck(dc->getASTContext(), allUnresolved);
@@ -2071,13 +2126,13 @@ AssociatedTypeInference::inferTypeWitnessesViaAssociatedType(
         !witnessHasImplementsAttrForRequiredName(typeDecl, assocType))
       continue;
 
-    if (typeDecl->isInvalid()) {
+    if (typeDecl->isRecursiveValidation()) {
       LLVM_DEBUG(llvm::dbgs() << "Recursive validation\n";);
       continue;
     }
 
-    if (typeDecl->isRecursiveValidation()) {
-      LLVM_DEBUG(llvm::dbgs() << "Recursive validation\n";);
+    if (typeDecl->isInvalid()) {
+      LLVM_DEBUG(llvm::dbgs() << "Invalid type witness\n";);
       continue;
     }
 
@@ -2496,7 +2551,11 @@ AssociatedTypeInference::computeFailureTypeWitness(
     if (!isAsyncIteratorProtocolNext(witness.first))
       continue;
 
-    if (!witness.second || witness.second->getDeclContext() != dc)
+    // Different extensions of the same nominal are OK, but if the witness is in
+    // a protocol extension or a superclass or something, give up.
+    if (!witness.second ||
+        witness.second->getDeclContext()->getSelfNominalTypeDecl()
+            != dc->getSelfNominalTypeDecl())
       continue;
 
     if (auto witnessFunc = dyn_cast<AbstractFunctionDecl>(witness.second)) {
@@ -2594,12 +2653,11 @@ AssociatedTypeInference::computeDerivedTypeWitness(
     return std::make_pair(Type(), nullptr);
 
   // Can we derive conformances for this protocol and adoptee?
-  NominalTypeDecl *derivingTypeDecl = dc->getSelfNominalTypeDecl();
-  if (!DerivedConformance::derivesProtocolConformance(dc, derivingTypeDecl,
-                                                      proto))
+  if (!DerivedConformance::derivesProtocolConformance(conformance))
     return std::make_pair(Type(), nullptr);
 
   // Try to derive the type witness.
+  NominalTypeDecl *derivingTypeDecl = dc->getSelfNominalTypeDecl();
   auto result = deriveTypeWitness(conformance, derivingTypeDecl, assocType);
   if (!result.first)
     return std::make_pair(Type(), nullptr);
@@ -2715,19 +2773,19 @@ bool AssociatedTypeInference::simplifyCurrentTypeWitnesses() {
   LLVM_DEBUG(llvm::dbgs() << "Simplifying type witnesses -- iteration " << iterations << "\n");
 
     if (++iterations > 100) {
-      llvm::errs() << "Too many iterations in simplifyCurrentTypeWitnesses()\n";
-
-      for (auto assocType : proto->getAssociatedTypeMembers()) {
-        if (conformance->hasTypeWitness(assocType))
-          continue;
+      ABORT([&](auto &out) {
+        out << "Too many iterations in simplifyCurrentTypeWitnesses()\n";
 
-        auto known = typeWitnesses.begin(assocType);
-        assert(known != typeWitnesses.end());
+        for (auto assocType : proto->getAssociatedTypeMembers()) {
+          if (conformance->hasTypeWitness(assocType))
+            continue;
 
-        llvm::errs() << assocType->getName() << ": " << known->first << "\n";
-      }
+          auto known = typeWitnesses.begin(assocType);
+          assert(known != typeWitnesses.end());
 
-      abort();
+          out << assocType->getName() << ": " << known->first << "\n";
+        }
+      });
     }
 
     auto selfTy = proto->getSelfInterfaceType()->getCanonicalType();
@@ -2901,18 +2959,14 @@ bool AssociatedTypeInference::checkCurrentTypeWitnesses(
   // Check any same-type requirements in the protocol's requirement signature.
   SubstOptions options = getSubstOptionsWithCurrentTypeWitnesses();
 
-  auto typeInContext = adoptee;
   ProtocolConformanceRef conformanceInContext(conformance);
   if (auto *genericEnv = conformance->getGenericEnvironment()) {
-    typeInContext = genericEnv->mapTypeIntoContext(typeInContext);
-    conformanceInContext =
-      conformanceInContext.subst(conformance->getType(),
-                                 genericEnv->getForwardingSubstitutionMap());
+    conformanceInContext = conformanceInContext.subst(
+        genericEnv->getForwardingSubstitutionMap());
   }
 
   auto substitutions =
-    SubstitutionMap::getProtocolSubstitutions(
-      proto, typeInContext, conformanceInContext);
+    SubstitutionMap::getProtocolSubstitutions(conformanceInContext);
 
   SmallVector<Requirement, 4> sanitizedRequirements;
   auto requirements = proto->getRequirementSignature().getRequirements();
@@ -3457,8 +3511,7 @@ static Comparison compareDeclsForInference(DeclContext *DC, ValueDecl *decl1,
   if (!sig1 || !sig2)
     return TypeChecker::compareDeclarations(DC, decl1, decl2);
 
-  auto selfParam = GenericTypeParamType::getType(/*depth*/ 0, /*index*/ 0,
-                                                 decl1->getASTContext());
+  auto selfParam = DC->getASTContext().TheSelfType;
 
   // Collect the protocols required by extension 1.
   Type class1;
@@ -4544,8 +4597,6 @@ AssociatedConformanceRequest::evaluate(Evaluator &eval,
                                        CanType origTy, ProtocolDecl *reqProto,
                                        unsigned index) const {
   auto subMap = SubstitutionMap::getProtocolSubstitutions(
-      conformance->getProtocol(),
-      conformance->getType(),
       ProtocolConformanceRef(conformance));
   auto substTy = origTy.subst(subMap);
 
diff --git a/lib/Sema/AsyncCallerExecutionMigration.cpp b/lib/Sema/AsyncCallerExecutionMigration.cpp
deleted file mode 100644
index 79ecf9f2b1c89..0000000000000
--- a/lib/Sema/AsyncCallerExecutionMigration.cpp
+++ /dev/null
@@ -1,197 +0,0 @@
-//===-- Sema/AsyncCallerExecutionMigration.cpp ------------------*- C++ -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2025 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// \file
-/// This file implements code migration support for the `AsyncCallerExecution`
-/// feature.
-///
-//===----------------------------------------------------------------------===//
-
-#include "AsyncCallerExecutionMigration.h"
-#include "swift/AST/ASTContext.h"
-#include "swift/AST/Decl.h"
-#include "swift/AST/DiagnosticsSema.h"
-#include "swift/AST/Expr.h"
-#include "swift/AST/TypeRepr.h"
-#include "swift/Basic/Assertions.h"
-#include "swift/Basic/Feature.h"
-#include "swift/Basic/TaggedUnion.h"
-#include "llvm/ADT/PointerUnion.h"
-
-using namespace swift;
-
-namespace {
-class AsyncCallerExecutionMigrationTarget {
-  ASTContext &ctx;
-  PointerUnion<ValueDecl *, AbstractClosureExpr *, FunctionTypeRepr *> node;
-  TaggedUnion<ActorIsolation, FunctionTypeIsolation> isolation;
-
-public:
-  AsyncCallerExecutionMigrationTarget(ASTContext &ctx, ValueDecl *decl,
-                                      ActorIsolation isolation)
-      : ctx(ctx), node(decl), isolation(isolation) {}
-
-  AsyncCallerExecutionMigrationTarget(ASTContext &ctx,
-                                      AbstractClosureExpr *closure,
-                                      ActorIsolation isolation)
-      : ctx(ctx), node(closure), isolation(isolation) {}
-
-  AsyncCallerExecutionMigrationTarget(ASTContext &ctx, FunctionTypeRepr *repr,
-                                      FunctionTypeIsolation isolation)
-      : ctx(ctx), node(repr), isolation(isolation) {}
-
-  /// Warns that the behavior of nonisolated async functions will change under
-  /// `AsyncCallerExecution` and suggests `@execution(concurrent)` to preserve
-  /// the current behavior.
-  void diagnose() const;
-};
-} // end anonymous namespace
-
-void AsyncCallerExecutionMigrationTarget::diagnose() const {
-  const auto feature = Feature::AsyncCallerExecution;
-
-  ASSERT(node);
-  ASSERT(ctx.LangOpts.getFeatureState(feature).isEnabledForAdoption());
-
-  ValueDecl *decl = nullptr;
-  ClosureExpr *closure = nullptr;
-  FunctionTypeRepr *functionRepr = nullptr;
-
-  if ((decl = node.dyn_cast<ValueDecl *>())) {
-    // Diagnose only explicit nodes.
-    if (decl->isImplicit()) {
-      return;
-    }
-
-    // If the attribute cannot appear on this kind of declaration, we can't
-    // diagnose it.
-    if (!DeclAttribute::canAttributeAppearOnDecl(DeclAttrKind::Execution,
-                                                 decl)) {
-      return;
-    }
-
-    // For storage, make sure we have an explicit getter to diagnose.
-    if (auto *storageDecl = dyn_cast<AbstractStorageDecl>(decl)) {
-      if (!storageDecl->getParsedAccessor(AccessorKind::Get)) {
-        return;
-      }
-    }
-  } else if (auto *anyClosure = node.dyn_cast<AbstractClosureExpr *>()) {
-    // Diagnose only explicit nodes.
-    if (anyClosure->isImplicit()) {
-      return;
-    }
-
-    // The only subclass that can be explicit is this one.
-    closure = cast<ClosureExpr>(anyClosure);
-  } else {
-    functionRepr = node.get<FunctionTypeRepr *>();
-  }
-
-  // The execution behavior changes only for nonisolated functions.
-  {
-    bool isNonisolated;
-    if (functionRepr) {
-      isNonisolated = isolation.get<FunctionTypeIsolation>().isNonIsolated();
-    } else {
-      auto isolation = this->isolation.get<ActorIsolation>();
-      isNonisolated = isolation.isNonisolated() || isolation.isUnspecified();
-    }
-
-    if (!isNonisolated) {
-      return;
-    }
-  }
-
-  // If the intended behavior is specified explicitly, don't diagnose.
-  {
-    const DeclAttributes *attrs = nullptr;
-    if (decl) {
-      attrs = &decl->getAttrs();
-    } else if (closure) {
-      attrs = &closure->getAttrs();
-    }
-
-    if (attrs && attrs->hasAttribute<ExecutionAttr>()) {
-      return;
-    }
-  }
-
-  // The execution behavior changes only for async functions.
-  {
-    bool isAsync = false;
-    if (decl) {
-      isAsync = decl->isAsync();
-    } else if (closure) {
-      isAsync = closure->isBodyAsync();
-    } else {
-      isAsync = functionRepr->isAsync();
-    }
-
-    if (!isAsync) {
-      return;
-    }
-  }
-
-  const ExecutionAttr attr(ExecutionKind::Concurrent, /*implicit=*/true);
-
-  const auto featureName = getFeatureName(feature);
-  if (decl) {
-    // Diagnose the function, but slap the attribute on the storage declaration
-    // instead if the function is an accessor.
-    auto *functionDecl = dyn_cast<AbstractFunctionDecl>(decl);
-    if (!functionDecl) {
-      auto *storageDecl = cast<AbstractStorageDecl>(decl);
-
-      // This whole logic assumes that an 'async' storage declaration only has
-      // a getter. Yell for an update if this ever changes.
-      ASSERT(!storageDecl->getAccessor(AccessorKind::Set));
-
-      functionDecl = storageDecl->getParsedAccessor(AccessorKind::Get);
-    }
-
-    ctx.Diags
-        .diagnose(functionDecl->getLoc(),
-                  diag::attr_execution_nonisolated_behavior_will_change_decl,
-                  featureName, functionDecl, &attr)
-        .fixItInsertAttribute(
-            decl->getAttributeInsertionLoc(/*forModifier=*/false), &attr);
-  } else if (closure) {
-    ctx.Diags
-        .diagnose(closure->getLoc(),
-                  diag::attr_execution_nonisolated_behavior_will_change_closure,
-                  featureName, &attr)
-        .fixItAddAttribute(&attr, closure);
-  } else {
-    ctx.Diags
-        .diagnose(
-            functionRepr->getStartLoc(),
-            diag::attr_execution_nonisolated_behavior_will_change_typerepr,
-            featureName, &attr)
-        .fixItInsertAttribute(functionRepr->getStartLoc(), &attr);
-  }
-}
-
-void swift::warnAboutNewNonisolatedAsyncExecutionBehavior(
-    ASTContext &ctx, FunctionTypeRepr *repr, FunctionTypeIsolation isolation) {
-  AsyncCallerExecutionMigrationTarget(ctx, repr, isolation).diagnose();
-}
-
-void swift::warnAboutNewNonisolatedAsyncExecutionBehavior(
-    ASTContext &ctx, ValueDecl *decl, ActorIsolation isolation) {
-  AsyncCallerExecutionMigrationTarget(ctx, decl, isolation).diagnose();
-}
-
-void swift::warnAboutNewNonisolatedAsyncExecutionBehavior(
-    ASTContext &ctx, AbstractClosureExpr *closure, ActorIsolation isolation) {
-  AsyncCallerExecutionMigrationTarget(ctx, closure, isolation).diagnose();
-}
diff --git a/lib/Sema/AsyncCallerExecutionMigration.h b/lib/Sema/AsyncCallerExecutionMigration.h
deleted file mode 100644
index 31a3218c18b66..0000000000000
--- a/lib/Sema/AsyncCallerExecutionMigration.h
+++ /dev/null
@@ -1,53 +0,0 @@
-//===-- Sema/AsyncCallerExecutionMigration.h --------------------*- C++ -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2025 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// \file
-/// This file provides code migration support for the `AsyncCallerExecution`
-/// feature.
-///
-//===----------------------------------------------------------------------===//
-
-#ifndef SWIFT_SEMA_ASYNCCALLEREXECUTIONMIGRATION_H
-#define SWIFT_SEMA_ASYNCCALLEREXECUTIONMIGRATION_H
-
-#include "swift/AST/ActorIsolation.h"
-#include "swift/AST/ExtInfo.h"
-
-namespace swift {
-
-class FunctionTypeRepr;
-class ValueDecl;
-class AbstractClosureExpr;
-
-/// Warns that the behavior of nonisolated async functions will change under
-/// `AsyncCallerExecution` and suggests `@execution(concurrent)` to preserve
-/// the current behavior.
-void warnAboutNewNonisolatedAsyncExecutionBehavior(
-    ASTContext &ctx, FunctionTypeRepr *node, FunctionTypeIsolation isolation);
-
-/// Warns that the behavior of nonisolated async functions will change under
-/// `AsyncCallerExecution` and suggests `@execution(concurrent)` to preserve
-/// the current behavior.
-void warnAboutNewNonisolatedAsyncExecutionBehavior(ASTContext &ctx,
-                                                   ValueDecl *node,
-                                                   ActorIsolation isolation);
-
-/// Warns that the behavior of nonisolated async functions will change under
-/// `AsyncCallerExecution` and suggests `@execution(concurrent)` to preserve
-/// the current behavior.
-void warnAboutNewNonisolatedAsyncExecutionBehavior(ASTContext &ctx,
-                                                   AbstractClosureExpr *node,
-                                                   ActorIsolation isolation);
-
-} // end namespace swift
-
-#endif /* SWIFT_SEMA_ASYNCCALLEREXECUTIONMIGRATION_H */
diff --git a/lib/Sema/BuilderTransform.cpp b/lib/Sema/BuilderTransform.cpp
index f05f89f130214..326fb242476f9 100644
--- a/lib/Sema/BuilderTransform.cpp
+++ b/lib/Sema/BuilderTransform.cpp
@@ -216,7 +216,7 @@ class ResultBuilderTransform
       return std::nullopt;
     }
 
-    auto *expr = element.get<Expr *>();
+    auto *expr = cast<Expr *>(element);
     if (auto *SVE = dyn_cast<SingleValueStmtExpr>(expr)) {
       // This should never be treated as an expression in a result builder, it
       // should have statement semantics.
@@ -269,12 +269,7 @@ class ResultBuilderTransform
     for (auto element : braceStmt->getElements()) {
       if (auto unsupported =
               transformBraceElement(element, newBody, buildBlockArguments)) {
-        // When in code completion mode, simply ignore unsported constructs to
-        // get results for anything that's unrelated to the unsupported
-        // constructs.
-        if (!ctx.CompletionCallback) {
-          return failTransform(*unsupported);
-        }
+        return failTransform(*unsupported);
       }
     }
 
@@ -655,7 +650,7 @@ class ResultBuilderTransform
         caseStmt->getCaseLabelItems(),
         caseStmt->hasUnknownAttr() ? caseStmt->getStartLoc() : SourceLoc(),
         caseStmt->getItemTerminatorLoc(), cloneBraceWith(body, newBody),
-        caseStmt->getCaseBodyVariablesOrEmptyArray(), caseStmt->isImplicit(),
+        caseStmt->getCaseBodyVariables(), caseStmt->isImplicit(),
         caseStmt->getFallthroughStmt());
 
     return std::make_pair(caseVarRef.get(), newCase);
@@ -780,8 +775,9 @@ class ResultBuilderTransform
 #undef UNSUPPORTED_STMT
 
 private:
-  static bool isBuildableIfChainRecursive(IfStmt *ifStmt, unsigned &numPayloads,
-                                          bool &isOptional) {
+  static void checkBuildableIfChainRecursive(IfStmt *ifStmt,
+                                             unsigned &numPayloads,
+                                             bool &isOptional) {
     // The 'then' clause contributes a payload.
     ++numPayloads;
 
@@ -789,7 +785,7 @@ class ResultBuilderTransform
     if (auto elseStmt = ifStmt->getElseStmt()) {
       // If it's 'else if', it contributes payloads recursively.
       if (auto elseIfStmt = dyn_cast<IfStmt>(elseStmt)) {
-        return isBuildableIfChainRecursive(elseIfStmt, numPayloads, isOptional);
+        checkBuildableIfChainRecursive(elseIfStmt, numPayloads, isOptional);
         // Otherwise it's just the one.
       } else {
         ++numPayloads;
@@ -799,8 +795,6 @@ class ResultBuilderTransform
     } else {
       isOptional = true;
     }
-
-    return true;
   }
 
   static bool hasUnconditionalElse(IfStmt *ifStmt) {
@@ -815,8 +809,7 @@ class ResultBuilderTransform
 
   bool isBuildableIfChain(IfStmt *ifStmt, unsigned &numPayloads,
                           bool &isOptional) {
-    if (!isBuildableIfChainRecursive(ifStmt, numPayloads, isOptional))
-      return false;
+    checkBuildableIfChainRecursive(ifStmt, numPayloads, isOptional);
 
     // If there's a missing 'else', we need 'buildOptional' to exist.
     if (isOptional && !builder.supportsOptional())
@@ -991,11 +984,11 @@ TypeChecker::applyResultBuilderBodyTransform(FuncDecl *func, Type builderType) {
   // of this decl; it's not part of the interface type.
   builderType = func->mapTypeIntoContext(builderType);
 
-  if (auto result = cs.matchResultBuilder(
-          func, builderType, resultContextType, resultConstraintKind,
-          /*contextualType=*/Type(),
-          cs.getConstraintLocator(func->getBody()))) {
-    if (result->isFailure())
+  {
+    auto result = cs.matchResultBuilder(
+        func, builderType, resultContextType, resultConstraintKind,
+        /*contextualType=*/Type(), cs.getConstraintLocator(func->getBody()));
+    if (!result || result->isFailure())
       return nullptr;
   }
 
@@ -1007,7 +1000,7 @@ TypeChecker::applyResultBuilderBodyTransform(FuncDecl *func, Type builderType) {
     cs.Options |= ConstraintSystemFlags::ForCodeCompletion;
     cs.solveForCodeCompletion(solutions);
 
-    CompletionContextFinder analyzer(target, func->getDeclContext());
+    CompletionContextFinder analyzer(target);
     if (analyzer.hasCompletion()) {
       filterSolutionsForCodeCompletion(solutions, analyzer);
       for (const auto &solution : solutions) {
@@ -1132,8 +1125,9 @@ ConstraintSystem::matchResultBuilder(AnyFunctionRef fn, Type builderType,
   if (fn.bodyHasExplicitReturnStmt()) {
     // Diagnostic mode means that solver couldn't reach any viable
     // solution, so let's diagnose presence of a `return` statement
-    // in the closure body.
-    if (shouldAttemptFixes()) {
+    // in the closure body. Avoid doing this for completion since we need to
+    // continue solving the body.
+    if (shouldAttemptFixes() && !isForCodeCompletion()) {
       if (recordFix(IgnoreResultBuilderWithReturnStmts::create(
               *this, builderType,
               getConstraintLocator(fn.getAbstractClosureExpr()))))
@@ -1157,21 +1151,13 @@ ConstraintSystem::matchResultBuilder(AnyFunctionRef fn, Type builderType,
     auto *body = transform.apply(fn.getBody());
 
     if (auto unsupported = transform.getUnsupportedElement()) {
-      assert(!body || getASTContext().CompletionCallback);
+      assert(!body);
 
       // If we aren't supposed to attempt fixes, fail.
       if (!shouldAttemptFixes()) {
         return getTypeMatchFailure(locator);
       }
 
-      // If we're solving for code completion and the body contains the code
-      // completion location, skipping it won't get us to a useful solution so
-      // just bail.
-      if (isForCodeCompletion() &&
-          containsIDEInspectionTarget(fn.getBody())) {
-        return getTypeMatchFailure(locator);
-      }
-
       // Record the first unhandled construct as a fix.
       if (recordFix(
               SkipUnhandledConstructInResultBuilder::create(
@@ -1180,6 +1166,13 @@ ConstraintSystem::matchResultBuilder(AnyFunctionRef fn, Type builderType,
         return getTypeMatchFailure(locator);
       }
 
+      // If we're solving for code completion and the body contains the code
+      // completion location, fall back to solving as a regular function body.
+      if (isForCodeCompletion() &&
+          containsIDEInspectionTarget(fn.getBody())) {
+        return std::nullopt;
+      }
+
       if (auto *closure =
               getAsExpr<ClosureExpr>(fn.getAbstractClosureExpr())) {
         recordTypeVariablesAsHoles(getClosureType(closure));
@@ -1296,9 +1289,7 @@ bool AnyFunctionRef::bodyHasExplicitReturnStmt() const {
     return false;
   }
 
-  auto &ctx = getAsDeclContext()->getASTContext();
-  return evaluateOrDefault(ctx.evaluator,
-                           BraceHasExplicitReturnStmtRequest{body}, false);
+  return body->hasExplicitReturnStmt(getAsDeclContext()->getASTContext());
 }
 
 void AnyFunctionRef::getExplicitReturnStmts(
diff --git a/lib/Sema/CMakeLists.txt b/lib/Sema/CMakeLists.txt
index 103435fa20d90..096539602eeee 100644
--- a/lib/Sema/CMakeLists.txt
+++ b/lib/Sema/CMakeLists.txt
@@ -1,7 +1,7 @@
 
 add_swift_host_library(swiftSema STATIC
   AssociatedTypeInference.cpp
-  AsyncCallerExecutionMigration.cpp
+  NonisolatedNonsendingByDefaultMigration.cpp
   BuilderTransform.cpp
   Comment.cpp
   CSApply.cpp
@@ -14,6 +14,7 @@ add_swift_host_library(swiftSema STATIC
   CSStep.cpp
   CSTrail.cpp
   CSFix.cpp
+  CSOptimizer.cpp
   CSDiagnostics.cpp
   CodeSynthesis.cpp
   CodeSynthesisDistributedActor.cpp
@@ -24,24 +25,26 @@ add_swift_host_library(swiftSema STATIC
   ConstraintSystem.cpp
   CompletionContextFinder.cpp
   DebuggerTestingTransform.cpp
-  DerivedConformanceActor.cpp
-  DerivedConformanceDistributedActor.cpp
-  DerivedConformanceAdditiveArithmetic.cpp
-  DerivedConformanceCaseIterable.cpp
-  DerivedConformanceCodable.cpp
-  DerivedConformanceCodingKey.cpp
-  DerivedConformanceDifferentiable.cpp
-  DerivedConformanceEquatableHashable.cpp
-  DerivedConformanceComparable.cpp
-  DerivedConformanceError.cpp
-  DerivedConformanceRawRepresentable.cpp
-  DerivedConformances.cpp
+  DerivedConformance/DerivedConformance.cpp
+  DerivedConformance/DerivedConformanceActor.cpp
+  DerivedConformance/DerivedConformanceAdditiveArithmetic.cpp
+  DerivedConformance/DerivedConformanceCaseIterable.cpp
+  DerivedConformance/DerivedConformanceCodable.cpp
+  DerivedConformance/DerivedConformanceCodingKey.cpp
+  DerivedConformance/DerivedConformanceComparable.cpp
+  DerivedConformance/DerivedConformanceDifferentiable.cpp
+  DerivedConformance/DerivedConformanceDistributedActor.cpp
+  DerivedConformance/DerivedConformanceEquatableHashable.cpp
+  DerivedConformance/DerivedConformanceError.cpp
+  DerivedConformance/DerivedConformanceRawRepresentable.cpp
   ImportResolution.cpp
   InstrumenterSupport.cpp
+  LegalConstExprVerifier.cpp
   LookupVisibleDecls.cpp
   MiscDiagnostics.cpp
   OpenedExistentials.cpp
   PCMacro.cpp
+  PerformanceHints.cpp
   PlaygroundTransform.cpp
   PreCheckTarget.cpp
   ResilienceDiagnostics.cpp
@@ -49,6 +52,7 @@ add_swift_host_library(swiftSema STATIC
   SyntacticElementTarget.cpp
   TypeOfReference.cpp
   TypeCheckAccess.cpp
+  TypeCheckAccessNotes.cpp
   TypeCheckAttr.cpp
   TypeCheckAttrABI.cpp
   TypeCheckAvailability.cpp
@@ -66,6 +70,7 @@ add_swift_host_library(swiftSema STATIC
   TypeCheckEffects.cpp
   TypeCheckExpr.cpp
   TypeCheckExprObjC.cpp
+  TypeCheckEmbedded.cpp
   TypeCheckGeneric.cpp
   TypeCheckInvertible.cpp
   TypeCheckMacros.cpp
diff --git a/lib/Sema/CSApply.cpp b/lib/Sema/CSApply.cpp
index 1f4cdb7fe0152..d51954866b89c 100644
--- a/lib/Sema/CSApply.cpp
+++ b/lib/Sema/CSApply.cpp
@@ -21,6 +21,7 @@
 #include "MiscDiagnostics.h"
 #include "OpenedExistentials.h"
 #include "TypeCheckConcurrency.h"
+#include "TypeCheckEmbedded.h"
 #include "TypeCheckMacros.h"
 #include "TypeCheckProtocol.h"
 #include "TypeCheckType.h"
@@ -104,28 +105,33 @@ Solution::computeSubstitutions(NullablePtr<ValueDecl> decl,
   if (openedTypes == OpenedTypes.end())
     return SubstitutionMap();
 
+  auto &ctx = getConstraintSystem().getASTContext();
+
   SmallVector<Type, 4> replacementTypes;
   for (const auto &opened : openedTypes->second) {
     auto type = getFixedType(opened.second);
     if (opened.first->isParameterPack()) {
       if (type->is<PlaceholderType>()) {
-        auto &ctx = type->getASTContext();
-        type =
-        PackType::get(ctx, {PackExpansionType::get(ctx.TheUnresolvedType,
-                                                   ctx.TheUnresolvedType)});
+        type = PackType::get(
+            ctx,
+            {PackExpansionType::get(ErrorType::get(ctx), ErrorType::get(ctx))});
       } else if (!type->is<PackType>())
         type = PackType::getSingletonPackExpansion(type);
     }
-    replacementTypes.push_back(type);
+    replacementTypes.push_back(simplifyType(type));
   }
 
   auto lookupConformanceFn =
-      [&](CanType original, Type replacement,
+      [&](InFlightSubstitution &IFS, Type original,
           ProtocolDecl *protoType) -> ProtocolConformanceRef {
+    auto replacement = original.subst(IFS);
     assert(!replacement->is<GenericTypeParamType>());
 
-    if (replacement->hasError() ||
-        isOpenedAnyObject(replacement) ||
+    if (replacement->hasError()) {
+      return ProtocolConformanceRef::forAbstract(ErrorType::get(replacement),
+                                                 protoType);
+    }
+    if (isOpenedAnyObject(replacement) ||
         replacement->is<GenericTypeParamType>()) {
       return ProtocolConformanceRef::forAbstract(replacement, protoType);
     }
@@ -145,9 +151,9 @@ Solution::computeSubstitutions(NullablePtr<ValueDecl> decl,
     return conformance;
   };
 
-  return SubstitutionMap::get(sig,
-                              replacementTypes,
-                              lookupConformanceFn);
+  auto subs = SubstitutionMap::get(sig, replacementTypes, lookupConformanceFn);
+  ASSERT(!subs.getRecursiveProperties().isSolverAllocated());
+  return subs;
 }
 
 // Lazily instantiate function definitions for class template specializations.
@@ -386,7 +392,7 @@ static bool willHaveConfusingConsumption(Type type,
                                          ConstraintLocatorBuilder locator,
                                          ConstraintSystem &cs) {
   assert(type);
-  if (!type->isNoncopyable())
+  if (type->isCopyable())
     return false; /// If it's a copyable type, there's no confusion.
 
   auto loc = cs.getConstraintLocator(locator);
@@ -451,7 +457,7 @@ namespace {
     void addLocalDeclToTypeCheck(Decl *D) {
       // If we're doing code completion, avoid doing any further type-checking,
       // that should instead be handled by TypeCheckASTNodeAtLocRequest.
-      if (ctx.CompletionCallback)
+      if (ctx.SourceMgr.hasIDEInspectionTargetBuffer())
         return;
 
       LocalDeclsToTypeCheck.push_back(D);
@@ -460,7 +466,7 @@ namespace {
     void addMacroToExpand(MacroExpansionExpr *E) {
       // If we're doing code completion, avoid doing any further type-checking,
       // that should instead be handled by TypeCheckASTNodeAtLocRequest.
-      if (ctx.CompletionCallback)
+      if (ctx.SourceMgr.hasIDEInspectionTargetBuffer())
         return;
 
       MacrosToExpand.push_back(E);
@@ -782,6 +788,7 @@ namespace {
           // We don't need to do any further adjustment once we've built the
           // curry thunk.
           return buildSingleCurryThunk(result, fnDecl,
+                                       adjustedFullType->castTo<FunctionType>(),
                                        adjustedFullType->castTo<FunctionType>(),
                                        locator);
         }
@@ -922,8 +929,9 @@ namespace {
     /// \returns An OpaqueValueExpr that provides a reference to the value
     /// stored within the expression or its metatype (if the base was a
     /// metatype).
-    Expr *openExistentialReference(Expr *base, ExistentialArchetypeType *archetype,
-                                   ValueDecl *member) {
+    Expr *openExistentialReference(Expr *base,
+                                   ExistentialArchetypeType *archetype,
+                                   ValueDecl *member, SourceLoc memberLoc) {
       assert(archetype && "archetype not already opened?");
 
       // Dig out the base type.
@@ -953,6 +961,11 @@ namespace {
 
       assert(baseTy->isAnyExistentialType() && "Type must be existential");
 
+      // Embedded Swift has limitations on the use of generic members of
+      // existentials. Diagnose them here.
+      diagnoseGenericMemberOfExistentialInEmbedded(
+          dc, memberLoc, baseTy, member);
+
       // If the base was an lvalue but it will only be treated as an
       // rvalue, turn the base into an rvalue now. This results in
       // better SILGen.
@@ -1312,6 +1325,21 @@ namespace {
       return callExpr;
     }
 
+    std::optional<ActorIsolation>
+    getIsolationFromFunctionType(FunctionType *thunkTy) {
+      switch (thunkTy->getIsolation().getKind()) {
+      case FunctionTypeIsolation::Kind::NonIsolated:
+      case FunctionTypeIsolation::Kind::Parameter:
+      case FunctionTypeIsolation::Kind::Erased:
+        return {};
+      case FunctionTypeIsolation::Kind::GlobalActor:
+        return ActorIsolation::forGlobalActor(
+            thunkTy->getIsolation().getGlobalActorType());
+      case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
+        return ActorIsolation::forCallerIsolationInheriting();
+      }
+    }
+
     /// Build a "{ args in base.fn(args) }" single-expression curry thunk.
     ///
     /// \param baseExpr The base expression to be captured, if warranted.
@@ -1326,6 +1354,7 @@ namespace {
     AutoClosureExpr *buildSingleCurryThunk(Expr *baseExpr, Expr *fnExpr,
                                            DeclContext *declOrClosure,
                                            FunctionType *thunkTy,
+                                           FunctionType *refTy,
                                            ConstraintLocatorBuilder locator) {
       const OptionSet<ParameterList::CloneFlags> options =
           (ParameterList::Implicit | ParameterList::NamedArguments);
@@ -1345,8 +1374,21 @@ namespace {
           new (ctx) AutoClosureExpr(/*set body later*/ nullptr, thunkTy, dc);
       thunk->setParameterList(thunkParamList);
       thunk->setThunkKind(AutoClosureExpr::Kind::SingleCurryThunk);
+
+      // TODO: We should do this in the ActorIsolation checker but for now it is
+      // too risky. This is a narrow fix for 6.2.
+      //
+      // The problem that this is working around is given an autoclosure that
+      // returns an autoclosure that partially applies over an instance method,
+      // we do not visit the inner autoclosure in the ActorIsolation checker
+      // meaning that we do not properly call setActorIsolation on the
+      // AbstractClosureExpr that we produce here.
+      if (auto isolation = getIsolationFromFunctionType(thunkTy)) {
+        thunk->setActorIsolation(*isolation);
+      }
+
       cs.cacheType(thunk);
-      
+
       // If the `self` type is existential, it must be opened.
       OpaqueValueExpr *baseOpened = nullptr;
       Expr *origBaseExpr = baseExpr;
@@ -1374,20 +1416,8 @@ namespace {
       // special handling.
       if (baseExpr) {
         if (auto *fnDecl = dyn_cast<AbstractFunctionDecl>(declOrClosure)) {
-          if (fnDecl->hasDynamicSelfResult()) {
-            Type convTy;
-
-            if (cs.getType(baseExpr)->hasOpenedExistential()) {
-              // FIXME: Sometimes we need to convert to an opened existential
-              // first, because CovariantReturnConversionExpr does not support
-              // direct conversions from a class C to an existential C & P.
-              convTy = cs.getType(baseExpr)->getMetatypeInstanceType();
-              convTy =
-                  thunkTy->getResult()->replaceCovariantResultType(convTy, 0);
-            } else {
-              convTy = thunkTy->getResult();
-            }
-
+          if (fnDecl->getDeclContext()->getSelfClassDecl()) {
+            auto convTy = refTy->getResult();
             if (!thunkBody->getType()->isEqual(convTy)) {
               thunkBody = cs.cacheType(
                   new (ctx) CovariantReturnConversionExpr(thunkBody, convTy));
@@ -1429,15 +1459,19 @@ namespace {
     /// \param thunkTy The type of the resulting thunk. This should be the
     /// type of the \c fnExpr, with any potential adjustments for things like
     /// concurrency.
+    /// \param refTy The type of the declaration reference inside the thunk.
+    ///              This might involve opened existentials or a covariant
+    ///              Self result.
     /// \param locator The locator pinned on the function reference carried
     /// by \p fnExpr. If the function has associated applied property wrappers,
     /// the locator is used to pull them in.
     AutoClosureExpr *buildSingleCurryThunk(Expr *fnExpr,
                                            DeclContext *declOrClosure,
                                            FunctionType *thunkTy,
+                                           FunctionType *refTy,
                                            ConstraintLocatorBuilder locator) {
       return buildSingleCurryThunk(/*baseExpr=*/nullptr, fnExpr, declOrClosure,
-                                   thunkTy, locator);
+                                   thunkTy, refTy, locator);
     }
 
     /// Build a "{ self in { args in self.fn(args) } }" nested curry thunk.
@@ -1447,12 +1481,16 @@ namespace {
     /// the parameters of the inner thunk.
     /// \param member The underlying function declaration to be called.
     /// \param outerThunkTy The type of the outer thunk.
+    /// \param outerRefTy The type of the declaration reference inside the thunk.
+    ///                   This might involve opened existentials or a covariant
+    ///                   Self result.
     /// \param memberLocator The locator pinned on the member reference. If the
     /// function has associated applied property wrappers, the locator is used
     /// to pull them in.
     AutoClosureExpr *
     buildDoubleCurryThunk(DeclRefExpr *memberRef, ValueDecl *member,
                           FunctionType *outerThunkTy,
+                          FunctionType *outerRefTy,
                           ConstraintLocatorBuilder memberLocator,
                           DeclNameLoc memberLoc, bool isDynamicLookup) {
       const auto selfThunkParam = outerThunkTy->getParams().front();
@@ -1511,6 +1549,31 @@ namespace {
         cs.cacheType(selfOpenedRef);
       }
 
+      auto outerActorIsolation = [&]() -> std::optional<ActorIsolation> {
+        auto resultType = outerThunkTy->getResult();
+        // Look through all optionals.
+        while (auto opt = resultType->getOptionalObjectType())
+          resultType = opt;
+        auto f =
+            getIsolationFromFunctionType(resultType->castTo<FunctionType>());
+        if (!f)
+          return {};
+
+        // If we have a non-async function and our "inferred" isolation is
+        // caller isolation inheriting, then we do not infer isolation and just
+        // use the default. The reason why we are doing this is:
+        //
+        // 1. nonisolated for synchronous functions is equivalent to
+        // nonisolated(nonsending).
+        //
+        // 2. There is a strong invariant in the compiler today that caller
+        // isolation inheriting is always async. By using nonisolated here, we
+        // avoid breaking that invariant.
+        if (!outerThunkTy->isAsync() && f->isCallerIsolationInheriting())
+          return {};
+        return f;
+      }();
+
       Expr *outerThunkBody = nullptr;
 
       // For an @objc optional member or a member found via dynamic lookup,
@@ -1540,7 +1603,14 @@ namespace {
       } else {
         auto *innerThunk = buildSingleCurryThunk(
             selfOpenedRef, memberRef, cast<DeclContext>(member),
-            outerThunkTy->getResult()->castTo<FunctionType>(), memberLocator);
+            outerThunkTy->getResult()->castTo<FunctionType>(),
+            outerRefTy->getResult()->castTo<FunctionType>(),
+            memberLocator);
+        assert((!outerActorIsolation ||
+                innerThunk->getActorIsolation().getKind() ==
+                    outerActorIsolation->getKind()) &&
+               "If we have an isolation for our double curry thunk it should "
+               "match our single curry thunk");
 
         // Rewrite the body to close the existential if warranted.
         if (hasOpenedExistential) {
@@ -1562,11 +1632,208 @@ namespace {
       outerThunk->setThunkKind(AutoClosureExpr::Kind::DoubleCurryThunk);
       outerThunk->setParameterList(
           ParameterList::create(ctx, SourceLoc(), selfParamDecl, SourceLoc()));
+
+      if (outerActorIsolation) {
+        outerThunk->setActorIsolation(*outerActorIsolation);
+      }
+
       cs.cacheType(outerThunk);
 
       return outerThunk;
     }
 
+    Expr *buildStaticCurryThunk(Expr *base, Expr *declRefExpr,
+                                AbstractFunctionDecl *member,
+                                FunctionType *curryThunkTy,
+                                FunctionType *curryRefTy,
+                                ConstraintLocatorBuilder locator,
+                                ConstraintLocatorBuilder memberLocator,
+                                bool openedExistential) {
+      if (cs.isStaticallyDerivedMetatype(base)) {
+        // Add a useless ".self" to avoid downstream diagnostics.
+        base = new (ctx) DotSelfExpr(base, SourceLoc(), base->getEndLoc(),
+                                     cs.getType(base));
+        cs.setType(base, base->getType());
+
+        // Skip the code below -- we're not building an extra level of
+        // call by applying the metatype; instead, the closure we just
+        // built is the curried reference.
+        return buildSingleCurryThunk(
+            base, declRefExpr, member,
+            curryThunkTy, curryRefTy,
+            memberLocator);
+      } else {
+        // Add a useless ".self" to avoid downstream diagnostics, in case
+        // the type ref is still a TypeExpr.
+        base = new (ctx) DotSelfExpr(base, SourceLoc(), base->getEndLoc(),
+                                     cs.getType(base));
+        // Introduce a capture variable.
+        cs.cacheType(base);
+        solution.setExprTypes(base);
+        auto capture = new (ctx) VarDecl(/*static*/ false,
+                                         VarDecl::Introducer::Let,
+                                         base->getEndLoc(),
+                                         ctx.getIdentifier("$base$"),
+                                         dc);
+        capture->setImplicit();
+        capture->setInterfaceType(base->getType()->mapTypeOutOfContext());
+
+        auto *capturePat =
+            NamedPattern::createImplicit(ctx, capture, base->getType());
+
+        auto *captureDecl = PatternBindingDecl::createImplicit(
+            ctx, StaticSpellingKind::None, capturePat, base, dc);
+
+        // Write the closure in terms of the capture.
+        auto baseRef = new (ctx)
+          DeclRefExpr(capture, DeclNameLoc(base->getLoc()), /*implicit*/ true);
+        baseRef->setType(base->getType());
+        cs.cacheType(baseRef);
+
+        auto *closure = buildSingleCurryThunk(
+          baseRef, declRefExpr, member,
+          curryThunkTy, curryRefTy,
+          memberLocator);
+
+        // Wrap the closure in a capture list.
+        auto captureEntry = CaptureListEntry(captureDecl);
+        auto captureExpr = CaptureListExpr::create(ctx, captureEntry,
+                                                   closure);
+        captureExpr->setImplicit();
+        captureExpr->setType(cs.getType(closure));
+        cs.cacheType(captureExpr);
+
+        Expr *finalExpr = captureExpr;
+        closeExistentials(finalExpr, locator,
+                          /*force*/ openedExistential);
+        return finalExpr;
+      }
+    }
+
+    Expr *buildDynamicMemberRef(Expr *base, Type baseTy,
+                                SourceLoc dotLoc,
+                                ConcreteDeclRef memberRef,
+                                Type openedType,
+                                Type adjustedOpenedType,
+                                DeclNameLoc memberLoc,
+                                ConstraintLocatorBuilder locator,
+                                ConstraintLocatorBuilder memberLocator,
+                                bool openedExistential,
+                                bool Implicit) {
+      base = cs.coerceToRValue(base);
+      Expr *ref = new (ctx) DynamicMemberRefExpr(base, dotLoc, memberRef,
+                                                 memberLoc);
+      ref->setImplicit(Implicit);
+      // FIXME: FunctionRefInfo
+
+      // Compute the type of the reference.
+      auto computeRefType = [&](Type refType) {
+        // If the base was an opened existential, erase the opened
+        // existential.
+        if (openedExistential) {
+          refType = typeEraseOpenedArchetypesFromEnvironment(
+              refType, baseTy->castTo<ExistentialArchetypeType>()->getGenericEnvironment());
+        }
+
+        return refType;
+      };
+
+      Type refType = computeRefType(openedType);
+      cs.setType(ref, refType);
+
+      // Adjust the declaration reference type, if required.
+      ref = adjustTypeForDeclReference(
+          ref, openedType, adjustedOpenedType, locator, computeRefType);
+
+      closeExistentials(ref, locator, /*force=*/openedExistential);
+
+      // We also need to handle the implicitly unwrap of the result
+      // of the called function if that's the type checking solution
+      // we ended up with.
+      return forceUnwrapIfExpected(ref, memberLocator);
+    }
+
+    /// FIXME: Simplify this horrible parameter list.
+    Expr *buildVarMemberRef(Expr *base, SourceLoc dotLoc,
+                            bool baseIsInstance,
+                            ConcreteDeclRef memberRef,
+                            DeclNameLoc memberLoc,
+                            Type containerTy,
+                            Type refTy,
+                            Type refTySelf,
+                            Type adjustedRefTy,
+                            Type adjustedRefTySelf,
+                            AccessSemantics semantics,
+                            ConstraintLocatorBuilder locator,
+                            ConstraintLocatorBuilder memberLocator,
+                            bool isSuper,
+                            bool isUnboundInstanceMember,
+                            bool Implicit) {
+      auto *varDecl = cast<VarDecl>(memberRef.getDecl());
+
+      bool loadImmediately = false;
+      auto resultType = [&loadImmediately](Type fnTy) -> Type {
+        Type resultTy = fnTy->castTo<FunctionType>()->getResult();
+        if (loadImmediately)
+          return LValueType::get(resultTy);
+        return resultTy;
+      };
+
+      // If we have an instance property that's treated as an rvalue
+      // but allows assignment (for initialization) in the current
+      // context, treat it as an rvalue that we immediately load.
+      // This is the AST that's expected by SILGen.
+      if (baseIsInstance && !resultType(refTy)->hasLValueType() &&
+          varDecl->mutability(dc, dyn_cast<DeclRefExpr>(base))
+              == StorageMutability::Initializable) {
+        loadImmediately = true;
+      }
+
+      if (isUnboundInstanceMember) {
+        assert(memberLocator.getBaseLocator() &&
+               cs.UnevaluatedRootExprs.count(
+                   getAsExpr(memberLocator.getBaseLocator()->getAnchor())) &&
+               "Attempt to reference an instance member of a metatype");
+        auto baseInstanceTy = cs.getType(base)
+            ->getInOutObjectType()->getMetatypeInstanceType();
+        base = new (ctx) UnevaluatedInstanceExpr(base, baseInstanceTy);
+        cs.cacheType(base);
+        base->setImplicit();
+      }
+
+      auto memberRefExpr
+        = new (ctx) MemberRefExpr(base, dotLoc, memberRef,
+                                  memberLoc, Implicit, semantics);
+      memberRefExpr->setIsSuper(isSuper);
+
+      auto resultTySelf = resultType(refTySelf);
+      cs.setType(memberRefExpr, resultTySelf);
+
+      Expr *result = memberRefExpr;
+      result = adjustTypeForDeclReference(result, resultTySelf,
+                                          resultType(adjustedRefTySelf),
+                                          locator);
+
+      // If the property is of dynamic 'Self' type, wrap an implicit
+      // conversion around the resulting expression, with the destination
+      // type having 'Self' swapped for the appropriate replacement
+      // type -- usually the base object type.
+      auto resultTy = resultType(refTy);
+      if (!resultTy->isEqual(resultTySelf)) {
+        result = cs.cacheType(new (ctx) CovariantReturnConversionExpr(
+            result, resultTy));
+      }
+
+      closeExistentials(result, locator);
+
+      // If we need to load, do so now.
+      if (loadImmediately) {
+        result = cs.addImplicitLoadExpr(result);
+      }
+
+      return forceUnwrapIfExpected(result, memberLocator);
+    }
+
     /// Build a new member reference with the given base and member.
     Expr *buildMemberRef(Expr *base, SourceLoc dotLoc,
                          SelectedOverload overload, DeclNameLoc memberLoc,
@@ -1615,7 +1882,7 @@ namespace {
         // \endcode
         //
         // Here `P.foo` would be replaced with `S.foo`
-        if (!isExistentialMetatype && baseTy->is<ProtocolType>() &&
+        if (!isExistentialMetatype && baseTy->isConstraintType() &&
             member->isStatic()) {
           auto selfParam =
               overload.adjustedOpenedFullType->castTo<FunctionType>()->getParams()[0];
@@ -1631,6 +1898,29 @@ namespace {
       // Build a member reference.
       auto memberRef = resolveConcreteDeclRef(member, memberLocator);
 
+      // If our member reference is a value generic, then the resulting
+      // expression is the type value one to access the underlying parameter's
+      // value.
+      //
+      // This can occur in code that does something like: 'type(of: x).a' where
+      // 'a' is the static value generic member.
+      if (auto gp = dyn_cast<GenericTypeParamDecl>(member)) {
+        ASSERT(gp->isValue());
+
+        auto refType = adjustedOpenedType;
+        auto ref = TypeValueExpr::createForDecl(memberLoc, gp, dc);
+        cs.setType(ref, refType);
+
+        auto gpTy = gp->getDeclaredInterfaceType();
+        auto subs = baseTy->getContextSubstitutionMap();
+        ref->setParamType(gpTy.subst(subs));
+
+        auto result = new (ctx) DotSyntaxBaseIgnoredExpr(base, dotLoc, ref,
+                                                         refType);
+        cs.setType(result, refType);
+        return result;
+      }
+
       // If we're referring to a member type, it's just a type
       // reference.
       if (auto *TD = dyn_cast<TypeDecl>(member)) {
@@ -1657,7 +1947,8 @@ namespace {
         Expr *ref = cs.cacheType(new (ctx) DotSyntaxBaseIgnoredExpr(
             base, dotLoc, dre, refTy));
 
-        ref = adjustTypeForDeclReference(ref, refTy, adjustedRefTy, locator);
+        ref = adjustTypeForDeclReference(ref, refTy, adjustedRefTy,
+                                         locator);
         return forceUnwrapIfExpected(ref, memberLocator);
       }
 
@@ -1675,12 +1966,15 @@ namespace {
 
       // If we opened up an existential when referencing this member, update
       // the base accordingly.
+      Type baseOpenedTy = baseTy;
       bool openedExistential = false;
 
       auto knownOpened = solution.OpenedExistentialTypes.find(
                            getConstraintSystem().getConstraintLocator(
                              memberLocator));
       if (knownOpened != solution.OpenedExistentialTypes.end()) {
+        baseOpenedTy = knownOpened->second;
+
         // Determine if we're going to have an OpenExistentialExpr around
         // this member reference.
         //
@@ -1701,8 +1995,9 @@ namespace {
             (!member->getDeclContext()->getSelfProtocolDecl() &&
              baseIsInstance && member->isInstanceMember())) {
           // Open the existential before performing the member reference.
-          base = openExistentialReference(base, knownOpened->second, member);
-          baseTy = knownOpened->second;
+          base = openExistentialReference(base, knownOpened->second, member,
+                                          memberLoc.getBaseNameLoc());
+          baseTy = baseOpenedTy;
           selfTy = baseTy;
           openedExistential = true;
         } else {
@@ -1765,133 +2060,64 @@ namespace {
       }
       assert(base && "Unable to convert base?");
 
+      // This is the type of the DeclRefExpr, where DynamicSelfType has
+      // been replaced with the static Self type of the member, ie the
+      // base class it is declared in.
+      Type refTySelf = refTy, adjustedRefTySelf = adjustedRefTy;
+
+      // Now, deal with DynamicSelfType.
+      if (overload.openedFullType->hasDynamicSelfType()) {
+        // We look at the original opened type with unsimplified type
+        // variables, because we only want to erase DynamicSelfType
+        // that appears in the original type of the member, and not
+        // one introduced by substitution.
+        refTySelf = simplifyType(
+            overload.openedFullType->eraseDynamicSelfType());
+        adjustedRefTySelf = simplifyType(
+            overload.adjustedOpenedFullType->eraseDynamicSelfType());
+
+        // Now replace DynamicSelfType with the actual base type
+        // of the call.
+        auto replacementTy = getDynamicSelfReplacementType(
+              baseOpenedTy, member, memberLocator.getBaseLocator());
+        refTy = simplifyType(
+              overload.openedFullType
+                  ->replaceDynamicSelfType(replacementTy));
+        adjustedRefTy = simplifyType(
+              overload.adjustedOpenedFullType
+                  ->replaceDynamicSelfType(replacementTy));
+      }
+
       // Handle dynamic references.
       if (!needsCurryThunk &&
           (isDynamic || member->getAttrs().hasAttribute<OptionalAttr>())) {
-        base = cs.coerceToRValue(base);
-        Expr *ref = new (ctx) DynamicMemberRefExpr(base, dotLoc, memberRef,
-                                                   memberLoc);
-        ref->setImplicit(Implicit);
-        // FIXME: FunctionRefInfo
-
-        // Compute the type of the reference.
-        auto computeRefType = [&](Type refType) {
-          // If the base was an opened existential, erase the opened
-          // existential.
-          if (openedExistential) {
-            refType = typeEraseOpenedArchetypesFromEnvironment(
-                refType, baseTy->castTo<ExistentialArchetypeType>()->getGenericEnvironment());
-          }
-
-          return refType;
-        };
-
-        Type refType = computeRefType(openedType);
-        cs.setType(ref, refType);
-
-        // Adjust the declaration reference type, if required.
-        ref = adjustTypeForDeclReference(
-            ref, openedType, adjustedOpenedType, locator, computeRefType);
-
-        closeExistentials(ref, locator, /*force=*/openedExistential);
-
-        // We also need to handle the implicitly unwrap of the result
-        // of the called function if that's the type checking solution
-        // we ended up with.
-        return forceUnwrapIfExpected(ref, memberLocator);
+        return buildDynamicMemberRef(base, baseTy, dotLoc, memberRef,
+                                     openedType, adjustedOpenedType,
+                                     memberLoc, locator, memberLocator,
+                                     openedExistential, Implicit);
       }
 
       // For properties, build member references.
-      if (auto *varDecl = dyn_cast<VarDecl>(member)) {
-        // \returns result of the given function type
-        bool loadImmediately = false;
-        auto resultType = [&loadImmediately](Type fnTy) -> Type {
-          Type resultTy = fnTy->castTo<FunctionType>()->getResult();
-          if (loadImmediately)
-            return LValueType::get(resultTy);
-          return resultTy;
-        };
-
-        // If we have an instance property that's treated as an rvalue
-        // but allows assignment (for initialization) in the current
-        // context, treat it as an rvalue that we immediately load.
-        // This is the AST that's expected by SILGen.
-        if (baseIsInstance && !resultType(refTy)->hasLValueType() &&
-            varDecl->mutability(dc, dyn_cast<DeclRefExpr>(base))
-                == StorageMutability::Initializable) {
-          loadImmediately = true;
-        }
-
-        if (isUnboundInstanceMember) {
-          assert(memberLocator.getBaseLocator() &&
-                 cs.UnevaluatedRootExprs.count(
-                     getAsExpr(memberLocator.getBaseLocator()->getAnchor())) &&
-                 "Attempt to reference an instance member of a metatype");
-          auto baseInstanceTy = cs.getType(base)
-              ->getInOutObjectType()->getMetatypeInstanceType();
-          base = new (ctx) UnevaluatedInstanceExpr(base, baseInstanceTy);
-          cs.cacheType(base);
-          base->setImplicit();
-        }
-
-        const auto hasDynamicSelf =
-            varDecl->getValueInterfaceType()->hasDynamicSelfType();
-
-        auto memberRefExpr
-          = new (ctx) MemberRefExpr(base, dotLoc, memberRef,
-                                    memberLoc, Implicit, semantics);
-        memberRefExpr->setIsSuper(isSuper);
-
-        if (hasDynamicSelf) {
-          refTy = refTy->replaceCovariantResultType(containerTy, 1);
-          adjustedRefTy = adjustedRefTy->replaceCovariantResultType(
-              containerTy, 1);
-        }
-
-        cs.setType(memberRefExpr, resultType(refTy));
-
-        Expr *result = memberRefExpr;
-        result = adjustTypeForDeclReference(result, resultType(refTy),
-                                            resultType(adjustedRefTy),
-                                            locator);
-        closeExistentials(result, locator);
-
-        // If the property is of dynamic 'Self' type, wrap an implicit
-        // conversion around the resulting expression, with the destination
-        // type having 'Self' swapped for the appropriate replacement
-        // type -- usually the base object type.
-        if (hasDynamicSelf) {
-          const auto conversionTy = adjustedOpenedType;
-          if (!containerTy->isEqual(conversionTy)) {
-            result = cs.cacheType(new (ctx) CovariantReturnConversionExpr(
-                result, conversionTy));
-          }
-        }
-
-        // If we need to load, do so now.
-        if (loadImmediately) {
-          result = cs.addImplicitLoadExpr(result);
-        }
-
-        return forceUnwrapIfExpected(result, memberLocator);
+      if (isa<VarDecl>(member)) {
+        return buildVarMemberRef(base, dotLoc, baseIsInstance,
+                                 memberRef, memberLoc, containerTy,
+                                 refTy, refTySelf, adjustedRefTy, adjustedRefTySelf,
+                                 semantics, locator, memberLocator,
+                                 isSuper, isUnboundInstanceMember, Implicit);
       }
 
-      auto *func = dyn_cast<FuncDecl>(member);
-      if (func && func->getResultInterfaceType()->hasDynamicSelfType()) {
-        refTy = refTy->replaceCovariantResultType(containerTy, 2);
-        adjustedRefTy = adjustedRefTy->replaceCovariantResultType(
-            containerTy, 2);
-      }
+      ASSERT(isa<AbstractFunctionDecl>(member) ||
+             isa<EnumElementDecl>(member));
 
       // Handle all other references.
       auto declRefExpr = new (ctx) DeclRefExpr(memberRef, memberLoc,
                                                Implicit, semantics);
       declRefExpr->setFunctionRefInfo(choice.getFunctionRefInfo());
-      declRefExpr->setType(refTy);
-      cs.setType(declRefExpr, refTy);
+      declRefExpr->setType(refTySelf);
+      cs.setType(declRefExpr, refTySelf);
       Expr *ref = declRefExpr;
 
-      ref = adjustTypeForDeclReference(ref, refTy, adjustedRefTy, locator);
+      ref = adjustTypeForDeclReference(ref, refTySelf, adjustedRefTySelf, locator);
 
       // A partial application thunk consists of two nested closures:
       //
@@ -1911,12 +2137,57 @@ namespace {
       // very specific shape, we only emit a single closure here and
       // capture the original SuperRefExpr, since its evaluation does not
       // have side effects, instead of abstracting out a 'self' parameter.
-      const auto isSuperPartialApplication = needsCurryThunk && isSuper;
-      if (isSuperPartialApplication) {
+      if (isUnboundInstanceMember) {
+        if (needsCurryThunk) {
+          // For an unbound reference to a method, all conversions, including
+          // dynamic 'Self' handling, are done within the thunk to support
+          // the edge case of an unbound reference to a 'Self'-returning class
+          // method on a protocol metatype. The result of calling the method
+          // must be downcast to the opened archetype before being erased to the
+          // subclass existential to cope with the expectations placed
+          // on 'CovariantReturnConversionExpr'.
+          auto *curryThunkTy = adjustedOpenedType->castTo<FunctionType>();
+          auto *curryRefTy = adjustedRefTy->castTo<FunctionType>();
+
+          // Replace the DeclRefExpr with a closure expression which SILGen
+          // knows how to emit.
+          ref = buildDoubleCurryThunk(declRefExpr, member,
+                                      curryThunkTy, curryRefTy,
+                                      memberLocator, memberLoc,
+                                      isDynamic);
+        }
+
+        ref = adjustTypeForDeclReference(
+            ref, cs.getType(ref), adjustedOpenedType,
+            locator);
+
+        // Reference to an unbound instance method.
+        Expr *result = new (ctx) DotSyntaxBaseIgnoredExpr(base, dotLoc,
+                                                              ref,
+                                                              cs.getType(ref));
+        cs.cacheType(result);
+        closeExistentials(result, locator, /*force=*/openedExistential);
+        return forceUnwrapIfExpected(result, memberLocator);
+
+      } else if (needsCurryThunk && isSuper) {
         ref = buildSingleCurryThunk(
             base, declRefExpr, cast<AbstractFunctionDecl>(member),
             adjustedOpenedType->castTo<FunctionType>(),
+            adjustedRefTy->castTo<FunctionType>()
+                ->getResult()->castTo<FunctionType>(),
             memberLocator);
+
+        // Handle DynamicSelfType.
+        if (!adjustedRefTy->isEqual(adjustedRefTySelf)) {
+          auto conversionTy = adjustedRefTy->castTo<FunctionType>()->getResult();
+          ref = cs.cacheType(new (ctx) CovariantFunctionConversionExpr(
+              ref, conversionTy));
+        }
+
+        // The thunk that is built for a 'super' method reference does not
+        // require application.
+        return forceUnwrapIfExpected(ref, memberLocator);
+
       } else if (needsCurryThunk) {
         // Another case where we want to build a single closure is when
         // we have a partial application of a static member. It is better
@@ -1926,95 +2197,34 @@ namespace {
         // or to evaluate the base as a capture and hand it down via the
         // capture list.
         if (isa<ConstructorDecl>(member) || member->isStatic()) {
-          if (cs.isStaticallyDerivedMetatype(base)) {
-            // Add a useless ".self" to avoid downstream diagnostics.
-            base = new (ctx) DotSelfExpr(base, SourceLoc(), base->getEndLoc(),
-                                         cs.getType(base));
-            cs.setType(base, base->getType());
-
-            // Skip the code below -- we're not building an extra level of
-            // call by applying the metatype; instead, the closure we just
-            // built is the curried reference.
-            return buildSingleCurryThunk(
-                base, declRefExpr, cast<AbstractFunctionDecl>(member),
-                adjustedOpenedType->castTo<FunctionType>(),
-                memberLocator);
-          } else {
-            // Add a useless ".self" to avoid downstream diagnostics, in case
-            // the type ref is still a TypeExpr.
-            base = new (ctx) DotSelfExpr(base, SourceLoc(), base->getEndLoc(),
-                                         cs.getType(base));
-            // Introduce a capture variable.
-            cs.cacheType(base);
-            solution.setExprTypes(base);
-            auto capture = new (ctx) VarDecl(/*static*/ false,
-                                             VarDecl::Introducer::Let,
-                                             SourceLoc(),
-                                             ctx.getIdentifier("$base$"),
-                                             dc);
-            capture->setImplicit();
-            capture->setInterfaceType(base->getType()->mapTypeOutOfContext());
-
-            auto *capturePat =
-                NamedPattern::createImplicit(ctx, capture, base->getType());
-
-            auto *captureDecl = PatternBindingDecl::createImplicit(
-                ctx, StaticSpellingKind::None, capturePat, base, dc);
-
-            // Write the closure in terms of the capture.
-            auto baseRef = new (ctx)
-              DeclRefExpr(capture, DeclNameLoc(base->getLoc()), /*implicit*/ true);
-            baseRef->setType(base->getType());
-            cs.cacheType(baseRef);
-            
-            auto *closure = buildSingleCurryThunk(
-              baseRef, declRefExpr, cast<AbstractFunctionDecl>(member),
+          return buildStaticCurryThunk(
+              base, declRefExpr, cast<AbstractFunctionDecl>(member),
               adjustedOpenedType->castTo<FunctionType>(),
-              memberLocator);
-              
-            // Wrap the closure in a capture list.
-            auto captureEntry = CaptureListEntry(captureDecl);
-            auto captureExpr = CaptureListExpr::create(ctx, captureEntry,
-                                                       closure);
-            captureExpr->setImplicit();
-            captureExpr->setType(cs.getType(closure));
-            cs.cacheType(captureExpr);
-            
-            Expr *finalExpr = captureExpr;
-            closeExistentials(finalExpr, locator,
-                              /*force*/ openedExistential);
-            return finalExpr;
-          }
+              adjustedRefTy->castTo<FunctionType>()
+                  ->getResult()->castTo<FunctionType>(),
+              locator, memberLocator, openedExistential);
         }
 
-        FunctionType *curryThunkTy = nullptr;
-        if (isUnboundInstanceMember) {
-          // For an unbound reference to a method, all conversions, including
-          // dynamic 'Self' handling, are done within the thunk to support
-          // the edge case of an unbound reference to a 'Self'-returning class
-          // method on a protocol metatype. The result of calling the method
-          // must be downcast to the opened archetype before being erased to the
-          // subclass existential to cope with the expectations placed
-          // on 'CovariantReturnConversionExpr'.
-          curryThunkTy = adjustedOpenedType->castTo<FunctionType>();
-        } else {
-          curryThunkTy = adjustedRefTy->castTo<FunctionType>();
-
-          // Check if we need to open an existential stored inside 'self'.
-          auto knownOpened = solution.OpenedExistentialTypes.find(
-              getConstraintSystem().getConstraintLocator(memberLocator));
-          if (knownOpened != solution.OpenedExistentialTypes.end()) {
-            curryThunkTy =
-                typeEraseOpenedArchetypesFromEnvironment(
-                  curryThunkTy, knownOpened->second->getGenericEnvironment())
-                    ->castTo<FunctionType>();
-          }
+        auto *curryThunkTy = adjustedRefTySelf->castTo<FunctionType>();
+        auto *curryRefTy = curryThunkTy;
+
+        // Check if we need to open an existential stored inside 'self'.
+        if (knownOpened != solution.OpenedExistentialTypes.end()) {
+          curryThunkTy =
+              typeEraseOpenedArchetypesFromEnvironment(
+                curryThunkTy, knownOpened->second->getGenericEnvironment())
+                  ->castTo<FunctionType>();
         }
 
         // Replace the DeclRefExpr with a closure expression which SILGen
         // knows how to emit.
-        ref = buildDoubleCurryThunk(declRefExpr, member, curryThunkTy,
-                                    memberLocator, memberLoc, isDynamic);
+        ref = buildDoubleCurryThunk(declRefExpr, member,
+                                    curryThunkTy, curryRefTy,
+                                    memberLocator, memberLoc,
+                                    isDynamic);
+
+        // Fall through, but with 'ref' now an AutoClosureExpr instead of
+        // a DeclRefExpr.
       }
 
       // If the member is a method with a dynamic 'Self' result type, wrap an
@@ -2023,55 +2233,18 @@ namespace {
       // replacement type -- usually the base object type.
       //
       // Note: For unbound references this is handled inside the thunk.
-      if (!isUnboundInstanceMember &&
-          !member->getDeclContext()->getSelfProtocolDecl()) {
-        if (auto func = dyn_cast<AbstractFunctionDecl>(member)) {
-          if (func->hasDynamicSelfResult() &&
-              !baseTy->getOptionalObjectType()) {
-            // FIXME: Once CovariantReturnConversionExpr (unchecked_ref_cast)
-            // supports a class existential dest., consider using the opened
-            // type directly to avoid recomputing the 'Self' replacement and
-            // substituting.
-            const Type replacementTy = getDynamicSelfReplacementType(
-                baseTy, member, memberLocator.getBaseLocator());
-            if (!replacementTy->isEqual(containerTy)) {
-              Type conversionTy =
-                  adjustedRefTy->replaceCovariantResultType(replacementTy, 2);
-              if (isSuperPartialApplication) {
-                conversionTy =
-                    conversionTy->castTo<FunctionType>()->getResult();
-              }
-
-              ref = cs.cacheType(new (ctx) CovariantFunctionConversionExpr(
-                  ref, conversionTy));
-            }
-          }
+      if (member->getDeclContext()->getSelfClassDecl()) {
+        if (!adjustedRefTy->isEqual(adjustedRefTySelf)) {
+          ref = cs.cacheType(new (ctx) CovariantFunctionConversionExpr(
+              ref, adjustedRefTy));
         }
       }
 
-      // The thunk that is built for a 'super' method reference does not
-      // require application.
-      if (isSuperPartialApplication) {
-        return forceUnwrapIfExpected(ref, memberLocator);
-      }
-
       ApplyExpr *apply;
       if (isa<ConstructorDecl>(member)) {
         // FIXME: Provide type annotation.
         ref = forceUnwrapIfExpected(ref, memberLocator);
         apply = ConstructorRefCallExpr::create(ctx, ref, base);
-      } else if (isUnboundInstanceMember) {
-        ref = adjustTypeForDeclReference(
-            ref, cs.getType(ref), adjustedOpenedType,
-            locator);
-
-        // Reference to an unbound instance method.
-        Expr *result = new (ctx) DotSyntaxBaseIgnoredExpr(base, dotLoc,
-                                                              ref,
-                                                              cs.getType(ref));
-        cs.cacheType(result);
-        closeExistentials(result, locator, /*force=*/openedExistential);
-        return forceUnwrapIfExpected(result, memberLocator);
       } else {
         assert((!baseIsInstance || member->isInstanceMember()) &&
                "can't call a static method on an instance");
@@ -2330,7 +2503,8 @@ namespace {
       auto memberLoc = cs.getCalleeLocator(cs.getConstraintLocator(locator));
       auto knownOpened = solution.OpenedExistentialTypes.find(memberLoc);
       if (knownOpened != solution.OpenedExistentialTypes.end()) {
-        base = openExistentialReference(base, knownOpened->second, subscript);
+        base = openExistentialReference(base, knownOpened->second, subscript,
+                                        args->getLoc());
         baseTy = knownOpened->second;
       }
 
@@ -2340,8 +2514,27 @@ namespace {
       // Coerce the index argument.
       auto openedFullFnType = simplifyType(selected.adjustedOpenedFullType)
                                   ->castTo<FunctionType>();
+
+      auto openedFullFnTypeSelf = openedFullFnType;
+
+      // Now, deal with DynamicSelfType.
+      if (selected.adjustedOpenedFullType->hasDynamicSelfType()) {
+        openedFullFnTypeSelf = simplifyType(
+            selected.adjustedOpenedFullType->eraseDynamicSelfType())
+                  ->castTo<FunctionType>();
+        auto replacementTy = getDynamicSelfReplacementType(
+            baseTy, subscript, memberLoc);
+        openedFullFnType = simplifyType(
+              selected.adjustedOpenedFullType
+                  ->replaceDynamicSelfType(replacementTy))
+                  ->castTo<FunctionType>();
+      }
+
       auto fullSubscriptTy = openedFullFnType->getResult()
                                   ->castTo<FunctionType>();
+      auto fullSubscriptTySelf = openedFullFnTypeSelf->getResult()
+                                  ->castTo<FunctionType>();
+
       auto appliedWrappers =
           solution.getAppliedPropertyWrappers(memberLoc->getAnchor());
       args = coerceCallArguments(
@@ -2395,37 +2588,28 @@ namespace {
       if (!base)
         return nullptr;
 
-      const auto hasDynamicSelf =
-          subscript->getElementInterfaceType()->hasDynamicSelfType();
-
       // Form the subscript expression.
       auto subscriptExpr = SubscriptExpr::create(
           ctx, base, args, subscriptRef, isImplicit, semantics);
-      cs.setType(subscriptExpr, fullSubscriptTy->getResult());
       subscriptExpr->setIsSuper(isSuper);
-      cs.setType(subscriptExpr,
-                 hasDynamicSelf
-                     ? fullSubscriptTy->getResult()->replaceCovariantResultType(
-                           containerTy, 0)
-                     : fullSubscriptTy->getResult());
+
+      cs.setType(subscriptExpr, fullSubscriptTySelf->getResult());
 
       Expr *result = subscriptExpr;
-      closeExistentials(result, locator);
 
       // If the element is of dynamic 'Self' type, wrap an implicit conversion
       // around the resulting expression, with the destination type having
       // 'Self' swapped for the appropriate replacement type -- usually the
       // base object type.
-      if (hasDynamicSelf) {
-        const auto conversionTy = simplifyType(
-            selected.adjustedOpenedType->castTo<FunctionType>()->getResult());
-
-        if (!containerTy->isEqual(conversionTy)) {
-          result = cs.cacheType(
-              new (ctx) CovariantReturnConversionExpr(result, conversionTy));
-        }
+      if (!fullSubscriptTy->getResult()->isEqual(
+            fullSubscriptTySelf->getResult())) {
+        result = cs.cacheType(
+            new (ctx) CovariantReturnConversionExpr(
+                result, fullSubscriptTy->getResult()));
       }
 
+      closeExistentials(result, locator);
+
       return result;
     }
 
@@ -2437,30 +2621,36 @@ namespace {
                                    bool implicit) {
       // The constructor was opened with the allocating type, not the
       // initializer type. Map the former into the latter.
-      auto *resultTy =
-          solution.simplifyType(openedFullType)->castTo<FunctionType>();
-
-      const auto selfTy = getBaseType(resultTy);
-
-      ParameterTypeFlags flags;
-      if (!selfTy->hasReferenceSemantics())
-        flags = flags.withInOut(true);
+      auto getOpenedInitializerType = [&](Type ty) -> FunctionType * {
+        auto *resultTy = solution.simplifyType(ty)->castTo<FunctionType>();
+        auto selfTy = getBaseType(resultTy);
+
+        ParameterTypeFlags flags;
+        if (!selfTy->hasReferenceSemantics())
+          flags = flags.withInOut(true);
+
+        auto selfParam = AnyFunctionType::Param(selfTy, Identifier(), flags);
+        return FunctionType::get({selfParam},
+                                 resultTy->getResult(),
+                                 resultTy->getExtInfo());
+      };
 
-      auto selfParam = AnyFunctionType::Param(selfTy, Identifier(), flags);
-      resultTy = FunctionType::get({selfParam}, resultTy->getResult(),
-                                   resultTy->getExtInfo());
+      auto *resultTySelf = getOpenedInitializerType(
+            openedFullType->eraseDynamicSelfType());
 
       // Build the constructor reference.
       Expr *ctorRef = cs.cacheType(
-          new (ctx) OtherConstructorDeclRefExpr(ref, loc, implicit, resultTy));
+          new (ctx) OtherConstructorDeclRefExpr(ref, loc, implicit, resultTySelf));
+
+      auto *resultTy = getOpenedInitializerType(
+            openedFullType->replaceDynamicSelfType(
+              cs.getType(base)->getWithoutSpecifierType()));
 
       // Wrap in covariant `Self` return if needed.
-      if (selfTy->hasReferenceSemantics()) {
-        auto covariantTy = resultTy->replaceCovariantResultType(
-          cs.getType(base)->getWithoutSpecifierType(), 2);
-        if (!covariantTy->isEqual(resultTy))
-          ctorRef = cs.cacheType(
-               new (ctx) CovariantFunctionConversionExpr(ctorRef, covariantTy));
+      if (!resultTy->isEqual(resultTySelf)) {
+        ASSERT(ref.getDecl()->getDeclContext()->getSelfClassDecl());
+        ctorRef = cs.cacheType(
+             new (ctx) CovariantFunctionConversionExpr(ctorRef, resultTy));
       }
 
       return ctorRef;
@@ -2469,18 +2659,39 @@ namespace {
     /// Build an implicit argument for keypath based dynamic lookup,
     /// which consists of KeyPath expression and a single component.
     ///
-    /// \param argType The type of the keypath subscript argument.
+    /// \param paramType The type of the keypath subscript parameter
+    ///                  this argument is passed to.
     /// \param dotLoc The location of the '.' preceding member name.
     /// \param memberLoc The locator to be associated with new argument.
-    Expr *buildKeyPathDynamicMemberArgExpr(Type argType, SourceLoc dotLoc,
+    Expr *buildKeyPathDynamicMemberArgExpr(Type paramType, SourceLoc dotLoc,
                                            ConstraintLocator *memberLoc) {
       using Component = KeyPathExpr::Component;
       auto *anchor = getAsExpr(memberLoc->getAnchor());
 
       auto makeKeyPath = [&](ArrayRef<Component> components) -> Expr * {
+        Type keyPathTy = paramType;
+
+        // If parameter of a dynamic member lookup is `& Sendable` type
+        // we need to check key path captures to determine whether the
+        // argument could be `& Sendable` as well or not.
+        if (paramType->isExistentialType() && paramType->isSendableType()) {
+          auto allCapturesAreSendable = [&](const Component &component) {
+            auto *argList = component.getArgs();
+            if (!argList)
+              return true;
+
+            return llvm::all_of(*argList, [&](const auto &arg) {
+              return solution.getResolvedType(arg.getExpr())->isSendableType();
+            });
+          };
+
+          if (!llvm::all_of(components, allCapturesAreSendable))
+            keyPathTy = paramType->getSuperclass();
+        }
+
         auto *kp = KeyPathExpr::createImplicit(ctx, /*backslashLoc*/ dotLoc,
                                                components, anchor->getEndLoc());
-        kp->setType(argType);
+        kp->setType(keyPathTy);
         cs.cacheExprTypes(kp);
 
         // See whether there's an equivalent ObjC key path string we can produce
@@ -2489,10 +2700,10 @@ namespace {
         return kp;
       };
 
-      Type keyPathTy = argType;
+      Type keyPathTy = paramType;
       if (auto *existential = keyPathTy->getAs<ExistentialType>()) {
         keyPathTy = existential->getSuperclass();
-        assert(isKnownKeyPathType(keyPathTy));
+        assert(keyPathTy->isKnownKeyPathType());
       }
 
       SmallVector<Component, 2> components;
@@ -2624,18 +2835,8 @@ namespace {
       // Form a reference to the function. The bridging operations are generic,
       // so we need to form substitutions and compute the resulting type.
       auto genericSig = fn->getGenericSignature();
-
       auto subMap = SubstitutionMap::get(
-          genericSig,
-          [&](SubstitutableType *type) -> Type {
-            assert(type->isEqual(genericSig.getGenericParams()[0]));
-            return valueType;
-          },
-          [&](CanType origType, Type replacementType,
-              ProtocolDecl *protoType) -> ProtocolConformanceRef {
-            assert(bridgedToObjectiveCConformance);
-            return bridgedToObjectiveCConformance;
-          });
+          genericSig, valueType, bridgedToObjectiveCConformance);
 
       ConcreteDeclRef fnSpecRef(fn, subMap);
 
@@ -2970,7 +3171,7 @@ namespace {
         DeclName constrName(ctx, DeclBaseName::createConstructor(), argLabels);
 
         ConcreteDeclRef witness =
-            conformance.getWitnessByName(type->getRValueType(), constrName);
+            conformance.getWitnessByName(constrName);
         if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
           return nullptr;
         return witness;
@@ -3090,9 +3291,6 @@ namespace {
       auto type = simplifyType(openedType);
       cs.setType(expr, type);
 
-      if (type->is<UnresolvedType>())
-        return expr;
-
       Type conformingType = type;
       if (auto baseType = conformingType->getOptionalObjectType()) {
         // The type may be optional due to a failable initializer in the
@@ -3108,17 +3306,13 @@ namespace {
 
       auto constrName = TypeChecker::getObjectLiteralConstructorName(ctx, expr);
 
-      ConcreteDeclRef witness = conformance.getWitnessByName(
-          conformingType->getRValueType(), constrName);
+      ConcreteDeclRef witness = conformance.getWitnessByName(constrName);
 
-      auto selectedOverload = solution.getOverloadChoiceIfAvailable(
+      auto selectedOverload = solution.getOverloadChoice(
           cs.getConstraintLocator(expr, ConstraintLocator::ConstructorMember));
 
-      if (!selectedOverload)
-        return nullptr;
-
-      auto fnType =
-          simplifyType(selectedOverload->adjustedOpenedType)->castTo<FunctionType>();
+      auto fnType = simplifyType(selectedOverload.adjustedOpenedType)
+                        ->castTo<FunctionType>();
 
       auto newArgs = coerceCallArguments(
           expr->getArgs(), fnType, witness, /*applyExpr=*/nullptr,
@@ -3223,8 +3417,20 @@ namespace {
 
     Expr *visitTypeValueExpr(TypeValueExpr *expr) {
       auto toType = simplifyType(cs.getType(expr));
-      assert(toType->isEqual(expr->getParamDecl()->getValueType()));
+      ASSERT(toType->isEqual(expr->getParamDecl()->getValueType()));
       cs.setType(expr, toType);
+
+      auto declRefRepr = cast<DeclRefTypeRepr>(expr->getRepr());
+      auto resolvedTy =
+          TypeResolution::resolveContextualType(declRefRepr, cs.DC,
+                                             TypeResolverContext::InExpression,
+                                                nullptr, nullptr, nullptr);
+
+      if (!resolvedTy || resolvedTy->hasError())
+        return nullptr;
+
+      expr->setParamType(resolvedTy);
+
       return expr;
     }
 
@@ -3272,14 +3478,7 @@ namespace {
     }
 
     Expr *visitUnresolvedMemberExpr(UnresolvedMemberExpr *expr) {
-      // If constraint solving resolved this to an UnresolvedType, then we're in
-      // an ambiguity tolerant mode used for diagnostic generation.  Just leave
-      // this as an unresolved member reference.
       Type resultTy = simplifyType(cs.getType(expr));
-      if (resultTy->hasUnresolvedType()) {
-        cs.setType(expr, resultTy);
-        return expr;
-      }
 
       // Find the selected member and base type.
       auto memberLocator = cs.getConstraintLocator(
@@ -3412,9 +3611,8 @@ namespace {
       auto &DE = ctx.Diags;
       DE.diagnose(UDE->getLoc(),
                   diag::warn_deprecated_conditional_conformance_outer_access,
-                  UDE->getName(),
-                  choice->getDescriptiveKind(), choiceParentDecl,
-                  innerChoice->getDescriptiveKind(), innerParentDecl);
+                  UDE->getName(), choice, choiceParentDecl, innerChoice,
+                  innerParentDecl);
 
       auto name = choiceParentDecl->getName().getBaseIdentifier();
       SmallString<32> namePlusDot = name.str();
@@ -3422,7 +3620,7 @@ namespace {
 
       DE.diagnose(UDE->getLoc(),
                   diag::fix_deprecated_conditional_conformance_outer_access,
-                  namePlusDot, choice->getDescriptiveKind())
+                  namePlusDot, choice)
           .fixItInsert(UDE->getStartLoc(), namePlusDot);
     }
 
@@ -3440,18 +3638,8 @@ namespace {
       // Determine the declaration selected for this overloaded reference.
       auto memberLocator = cs.getConstraintLocator(expr,
                                                    ConstraintLocator::Member);
-      auto selectedElt = solution.getOverloadChoiceIfAvailable(memberLocator);
-
-      if (!selectedElt) {
-        // If constraint solving resolved this to an UnresolvedType, then we're
-        // in an ambiguity tolerant mode used for diagnostic generation.  Just
-        // leave this as whatever type of member reference it already is.
-        Type resultTy = simplifyType(cs.getType(expr));
-        cs.setType(expr, resultTy);
-        return expr;
-      }
+      auto selected = solution.getOverloadChoice(memberLocator);
 
-      auto selected = *selectedElt;
       if (!selected.choice.getBaseType()) {
         // This is one of the "outer alternatives", meaning the innermost
         // methods didn't work out.
@@ -3600,6 +3788,8 @@ namespace {
       if (!argExpr)
         return nullptr;
 
+      solution.recordSingleArgMatchingChoice(cs.getConstraintLocator(expr));
+
       // Build an argument list.
       auto *argList =
           ArgumentList::forImplicitSingle(ctx, ctx.Id_dynamicMember, argExpr);
@@ -3768,39 +3958,17 @@ namespace {
     Expr *visitSubscriptExpr(SubscriptExpr *expr) {
       auto *memberLocator =
           cs.getConstraintLocator(expr, ConstraintLocator::SubscriptMember);
-      auto overload = solution.getOverloadChoiceIfAvailable(memberLocator);
-
-      // Handles situation where there was a solution available but it didn't
-      // have a proper overload selected from subscript call, might be because
-      // solver was allowed to return free or unresolved types, which can
-      // happen while running diagnostics on one of the expressions.
-      if (!overload) {
-        auto *base = expr->getBase();
-        auto &de = ctx.Diags;
-        auto baseType = cs.getType(base);
-
-        if (auto errorType = baseType->getAs<ErrorType>()) {
-          de.diagnose(base->getLoc(), diag::cannot_subscript_base,
-                      errorType->getOriginalType())
-              .highlight(base->getSourceRange());
-        } else {
-          de.diagnose(base->getLoc(), diag::cannot_subscript_ambiguous_base)
-              .highlight(base->getSourceRange());
-        }
-
-        return nullptr;
-      }
-
-      if (overload->choice.isKeyPathDynamicMemberLookup()) {
+      auto overload = solution.getOverloadChoice(memberLocator);
+      if (overload.choice.isKeyPathDynamicMemberLookup()) {
         return buildDynamicMemberLookupRef(
             expr, expr->getBase(), expr->getArgs()->getStartLoc(), SourceLoc(),
-            *overload, memberLocator);
+            overload, memberLocator);
       }
 
       return buildSubscript(expr->getBase(), expr->getArgs(),
                             cs.getConstraintLocator(expr), memberLocator,
                             expr->isImplicit(), expr->getAccessSemantics(),
-                            *overload);
+                            overload);
     }
 
     /// "Finish" an array expression by filling in the semantic expression.
@@ -3822,7 +3990,7 @@ namespace {
         DeclName name(ctx, DeclBaseName::createConstructor(),
                       {ctx.Id_arrayLiteral});
         ConcreteDeclRef witness =
-            conformance.getWitnessByName(arrayTy->getRValueType(), name);
+            conformance.getWitnessByName(name);
         if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
           return nullptr;
         expr->setInitializer(witness);
@@ -3868,7 +4036,7 @@ namespace {
       DeclName name(ctx, DeclBaseName::createConstructor(),
                     {ctx.Id_dictionaryLiteral});
       ConcreteDeclRef witness =
-          conformance.getWitnessByName(dictionaryTy->getRValueType(), name);
+          conformance.getWitnessByName(name);
       if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
         return nullptr;
       expr->setInitializer(witness);
@@ -4781,7 +4949,6 @@ namespace {
     Expr *visitEditorPlaceholderExpr(EditorPlaceholderExpr *E) {
       simplifyExprType(E);
       auto valueType = cs.getType(E);
-      assert(!valueType->hasUnresolvedType());
 
       // Synthesize a call to _undefined() of appropriate type.
       FuncDecl *undefinedDecl = ctx.getUndefined();
@@ -4982,9 +5149,6 @@ namespace {
           // If the property is settable, we don't know whether the
           // user wanted the getter or setter. Provide notes for each.
           if (isSettable) {
-            // Flush the primary diagnostic. We have notes to add.
-            primaryDiag.flush();
-
             // Add notes for the getter and setter, respectively.
             de.diagnose(modifierLoc, diag::expr_selector_add_modifier, false,
                         var)
@@ -5053,8 +5217,7 @@ namespace {
 
         de.diagnose(E->getLoc(), diag::expr_selector_not_objc, foundDecl)
             .highlight(subExpr->getSourceRange());
-        de.diagnose(foundDecl, diag::make_decl_objc,
-                    foundDecl->getDescriptiveKind())
+        de.diagnose(foundDecl, diag::make_decl_objc, foundDecl)
             .fixItInsert(foundDecl->getAttributeInsertionLoc(false), "@objc ");
         return E;
       }
@@ -5114,13 +5277,6 @@ namespace {
       auto componentTy = baseTy;
       for (unsigned i : indices(E->getComponents())) {
         auto &origComponent = E->getMutableComponents()[i];
-        
-        // If there were unresolved types, we may end up with a null base for
-        // following components.
-        if (!componentTy) {
-          resolvedComponents.push_back(origComponent);
-          continue;
-        }
 
         auto kind = origComponent.getKind();
         auto componentLocator =
@@ -5135,15 +5291,8 @@ namespace {
         // If this is an unresolved link, make sure we resolved it.
         if (kind == KeyPathExpr::Component::Kind::UnresolvedMember ||
             kind == KeyPathExpr::Component::Kind::UnresolvedSubscript) {
-          auto foundDecl = solution.getOverloadChoiceIfAvailable(calleeLoc);
-          if (!foundDecl) {
-            // If we couldn't resolve the component, leave it alone.
-            resolvedComponents.push_back(origComponent);
-            componentTy = origComponent.getComponentType();
-            continue;
-          }
-
-          isDynamicMember = foundDecl->choice.isAnyDynamicMemberLookup();
+          auto foundDecl = solution.getOverloadChoice(calleeLoc);
+          isDynamicMember = foundDecl.choice.isAnyDynamicMemberLookup();
 
           // If this was a @dynamicMemberLookup property, then we actually
           // form a subscript reference, so switch the kind.
@@ -5184,9 +5333,6 @@ namespace {
           // Chaining always forces the element to be an rvalue.
           auto objectTy =
               componentTy->getWithoutSpecifierType()->getOptionalObjectType();
-          if (componentTy->hasUnresolvedType() && !objectTy) {
-            objectTy = componentTy;
-          }
           assert(objectTy);
           
           auto loc = origComponent.getLoc();
@@ -5209,19 +5355,18 @@ namespace {
           }
           break;
         }
-        case KeyPathExpr::Component::Kind::Invalid:
-        case KeyPathExpr::Component::Kind::CodeCompletion: {
-          auto component = origComponent;
-          component.setComponentType(leafTy);
-          resolvedComponents.push_back(component);
-          break;
-        }
         case KeyPathExpr::Component::Kind::Identity: {
           auto component = origComponent;
           component.setComponentType(componentTy);
           resolvedComponents.push_back(component);
           break;
         }
+        case KeyPathExpr::Component::Kind::CodeCompletion:
+          llvm_unreachable("solver-based completion shouldn't do CSApply");
+          break;
+        case KeyPathExpr::Component::Kind::Invalid:
+          llvm_unreachable("should have been diagnosed");
+          break;
         case KeyPathExpr::Component::Kind::Member:
         case KeyPathExpr::Component::Kind::Subscript:
         case KeyPathExpr::Component::Kind::Apply:
@@ -5237,8 +5382,7 @@ namespace {
       }
 
       // Wrap a non-optional result if there was chaining involved.
-      if (didOptionalChain && componentTy &&
-          !componentTy->hasUnresolvedType() &&
+      if (didOptionalChain &&
           !componentTy->getWithoutSpecifierType()->isEqual(leafTy)) {
         auto component = KeyPathExpr::Component::forOptionalWrap(leafTy);
         resolvedComponents.push_back(component);
@@ -5367,15 +5511,9 @@ namespace {
       Type objectTy;
       if (auto lvalue = optionalTy->getAs<LValueType>()) {
         objectTy = lvalue->getObjectType()->getOptionalObjectType();
-        if (optionalTy->hasUnresolvedType() && !objectTy) {
-          objectTy = optionalTy;
-        }
         objectTy = LValueType::get(objectTy);
       } else {
         objectTy = optionalTy->getOptionalObjectType();
-        if (optionalTy->hasUnresolvedType() && !objectTy) {
-          objectTy = optionalTy;
-        }
       }
       assert(objectTy);
 
@@ -5580,6 +5718,18 @@ namespace {
       E->setMacroRef(macroRef);
       E->setType(expandedType);
 
+      auto fnType =
+          simplifyType(overload.adjustedOpenedType)->castTo<FunctionType>();
+
+      auto newArgs = coerceCallArguments(
+          E->getArgs(), fnType, macroRef, /*applyExpr=*/nullptr,
+          cs.getConstraintLocator(E, ConstraintLocator::ApplyArgument),
+          solution.getAppliedPropertyWrappers(E));
+      if (!newArgs)
+        return nullptr;
+
+      E->setArgs(newArgs);
+
       // FIXME: Expansion should be lazy.
       // i.e. 'ExpandMacroExpansionExprRequest' should be sinked into
       // 'getRewritten()', and performed on-demand. Unfortunately that requires
@@ -6038,31 +6188,35 @@ static bool hasCurriedSelf(ConstraintSystem &cs, ConcreteDeclRef callee,
 }
 
 /// Apply the contextually Sendable flag to the given expression,
-static void applyContextualClosureFlags(Expr *expr, bool implicitSelfCapture,
-                                        bool inheritActorContext,
-                                        bool isPassedToSendingParameter,
-                                        bool requiresDynamicIsolationChecking) {
+static void applyContextualClosureFlags(Expr *expr, unsigned paramIdx,
+                                        const ParameterListInfo &paramInfo,
+                                        bool requiresDynamicIsolationChecking,
+                                        bool isMacroArg) {
   if (auto closure = dyn_cast<ClosureExpr>(expr)) {
-    closure->setAllowsImplicitSelfCapture(implicitSelfCapture);
-    closure->setInheritsActorContext(inheritActorContext);
-    closure->setIsPassedToSendingParameter(isPassedToSendingParameter);
+    closure->setAllowsImplicitSelfCapture(
+        paramInfo.isImplicitSelfCapture(paramIdx));
+
+    auto [inheritActorContext, modifier] =
+        paramInfo.inheritsActorContext(paramIdx);
+    closure->setInheritsActorContext(inheritActorContext, modifier);
+
+    closure->setIsPassedToSendingParameter(
+        paramInfo.isSendingParameter(paramIdx));
     closure->setRequiresDynamicIsolationChecking(
         requiresDynamicIsolationChecking);
+    closure->setIsMacroArgument(isMacroArg);
     return;
   }
 
   if (auto captureList = dyn_cast<CaptureListExpr>(expr)) {
-    applyContextualClosureFlags(captureList->getClosureBody(),
-                                implicitSelfCapture, inheritActorContext,
-                                isPassedToSendingParameter,
-                                requiresDynamicIsolationChecking);
+    applyContextualClosureFlags(captureList->getClosureBody(), paramIdx,
+                                paramInfo, requiresDynamicIsolationChecking,
+                                isMacroArg);
   }
 
   if (auto identity = dyn_cast<IdentityExpr>(expr)) {
-    applyContextualClosureFlags(identity->getSubExpr(), implicitSelfCapture,
-                                inheritActorContext,
-                                isPassedToSendingParameter,
-                                requiresDynamicIsolationChecking);
+    applyContextualClosureFlags(identity->getSubExpr(), paramIdx, paramInfo,
+                                requiresDynamicIsolationChecking, isMacroArg);
   }
 }
 
@@ -6187,19 +6341,16 @@ ArgumentList *ExprRewriter::coerceCallArguments(
   }();
 
   auto applyFlagsToArgument = [&paramInfo,
-                               &closuresRequireDynamicIsolationChecking](
-                                  unsigned paramIdx, Expr *argument) {
+                               &closuresRequireDynamicIsolationChecking,
+                               &locator](unsigned paramIdx, Expr *argument) {
     if (!isClosureLiteralExpr(argument))
       return;
 
-    bool isImplicitSelfCapture = paramInfo.isImplicitSelfCapture(paramIdx);
-    bool inheritsActorContext = paramInfo.inheritsActorContext(paramIdx);
-    bool isPassedToSendingParameter = paramInfo.isSendingParameter(paramIdx);
+    bool isMacroArg = isExpr<MacroExpansionExpr>(locator.getAnchor());
 
-    applyContextualClosureFlags(argument, isImplicitSelfCapture,
-                                inheritsActorContext,
-                                isPassedToSendingParameter,
-                                closuresRequireDynamicIsolationChecking);
+    applyContextualClosureFlags(argument, paramIdx, paramInfo,
+                                closuresRequireDynamicIsolationChecking,
+                                isMacroArg);
   };
 
   // Quickly test if any further fix-ups for the argument types are necessary.
@@ -6423,7 +6574,8 @@ ArgumentList *ExprRewriter::coerceCallArguments(
           cs.getConstraintLocator(argLoc));
       if (knownOpened != solution.OpenedExistentialTypes.end()) {
         argExpr = openExistentialReference(
-            argExpr, knownOpened->second, callee.getDecl());
+            argExpr, knownOpened->second, callee.getDecl(),
+            apply ? apply->getLoc() : argExpr->getLoc());
         argType = cs.getType(argExpr);
       }
     }
@@ -6482,18 +6634,31 @@ ArgumentList *ExprRewriter::coerceCallArguments(
   return ArgumentList::createTypeChecked(ctx, args, newArgs);
 }
 
-/// Whether the given expression is a closure that should inherit
-/// the actor context from where it was formed.
-static bool closureInheritsActorContext(Expr *expr) {
+/// Looks through any non-semantic expressions and a capture list
+/// to find out whether the given expression is an explicit closure.
+static ClosureExpr *isExplicitClosureExpr(Expr *expr) {
   if (auto IE = dyn_cast<IdentityExpr>(expr))
-    return closureInheritsActorContext(IE->getSubExpr());
+    return isExplicitClosureExpr(IE->getSubExpr());
 
   if (auto CLE = dyn_cast<CaptureListExpr>(expr))
-    return closureInheritsActorContext(CLE->getClosureBody());
+    return isExplicitClosureExpr(CLE->getClosureBody());
 
-  if (auto CE = dyn_cast<ClosureExpr>(expr))
+  return dyn_cast<ClosureExpr>(expr);
+}
+
+/// Whether the given expression is a closure that should inherit
+/// the actor context from where it was formed.
+static bool closureInheritsActorContext(Expr *expr) {
+  if (auto *CE = isExplicitClosureExpr(expr))
     return CE->inheritsActorContext();
+  return false;
+}
 
+/// Determine whether the given expression is a closure that
+/// is explicitly marked as `@concurrent`.
+static bool isClosureMarkedAsConcurrent(Expr *expr) {
+  if (auto *CE = isExplicitClosureExpr(expr))
+    return CE->getAttrs().hasAttribute<ConcurrentAttr>();
   return false;
 }
 
@@ -6827,7 +6992,7 @@ bool ExprRewriter::peepholeCollectionUpcast(Expr *expr, Type toType,
 
   // Array literals.
   if (auto arrayLiteral = dyn_cast<ArrayExpr>(expr)) {
-    if (Type elementType = toType->isArrayType()) {
+    if (auto elementType = toType->getArrayElementType()) {
       peepholeArrayUpcast(arrayLiteral, toType, bridged, elementType, locator);
       return true;
     }
@@ -6949,12 +7114,10 @@ Expr *ExprRewriter::coerceExistential(Expr *expr, Type toType,
   Type openedFromInstanceType = openedFromType;
 
   // Look through metatypes.
-  while ((fromInstanceType->is<UnresolvedType>() ||
-          fromInstanceType->is<AnyMetatypeType>()) &&
+  while (fromInstanceType->is<AnyMetatypeType>() &&
          toInstanceType->is<ExistentialMetatypeType>()) {
-    if (!fromInstanceType->is<UnresolvedType>())
-      fromInstanceType = fromInstanceType->getMetatypeInstanceType();
-    if (openedFromInstanceType && !openedFromInstanceType->is<UnresolvedType>())
+    fromInstanceType = fromInstanceType->getMetatypeInstanceType();
+    if (openedFromInstanceType)
       openedFromInstanceType = openedFromInstanceType->getMetatypeInstanceType();
     toInstanceType = toInstanceType->getMetatypeInstanceType();
   }
@@ -7059,6 +7222,9 @@ Expr *ConstraintSystem::addImplicitLoadExpr(Expr *expr) {
 
 Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
                                  ConstraintLocatorBuilder locator) {
+  ASSERT(toType && !toType->hasError() &&
+         !toType->hasTypeVariableOrPlaceholder());
+
   // Diagnose conversions to invalid function types that couldn't be performed
   // beforehand because of placeholders.
   if (auto *fnTy = toType->getAs<FunctionType>()) {
@@ -7086,9 +7252,6 @@ Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
   if (knownRestriction != solution.ConstraintRestrictions.end()) {
     switch (knownRestriction->second) {
     case ConversionRestrictionKind::DeepEquality: {
-      if (toType->hasUnresolvedType())
-        break;
-
       // HACK: Fix problem related to Swift 4 mode (with assertions),
       // since Swift 4 mode allows passing arguments with extra parens
       // to parameters which don't expect them, it should be supported
@@ -7403,17 +7566,15 @@ Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
     if (!substitutions.empty()) {
       // Compute the underlying type by replacing all opaque archetypes with
       // the fixed type of their opened type.
-      auto underlyingType = toType.subst(
-        [&](SubstitutableType *type) -> Type {
-          if (auto *opaqueType = type->getAs<OpaqueTypeArchetypeType>()) {
+      auto underlyingType = toType.transformRec(
+        [&](TypeBase *type) -> std::optional<Type> {
+          if (auto *opaqueType = dyn_cast<OpaqueTypeArchetypeType>(type)) {
             if (opaqueType->getDecl() == opaqueDecl) {
               return opaqueType->getInterfaceType().subst(substitutions);
             }
           }
-          return type;
-        },
-        LookUpConformanceInModule(),
-        SubstFlags::SubstituteOpaqueArchetypes);
+          return std::nullopt;
+        });
 
       // Coerce the result expression to the underlying type.
       // FIXME: Wrong locator?
@@ -7658,11 +7819,13 @@ Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
     }
 
     // If we have a ClosureExpr, then we can safely propagate a global actor
-    // to the closure without invalidating prior analysis.
+    // to the closure if it's not explicitly marked as `@concurrent` without
+    // invalidating prior analysis.
     fromEI = fromFunc->getExtInfo();
-    if (toEI.getGlobalActor() && !fromEI.getGlobalActor()) {
-      auto newFromFuncType = fromFunc->withExtInfo(
-          fromEI.withGlobalActor(toEI.getGlobalActor()));
+    if (toEI.getGlobalActor() && !fromEI.getGlobalActor() &&
+        !isClosureMarkedAsConcurrent(expr)) {
+      auto newFromFuncType =
+          fromFunc->withExtInfo(fromEI.withGlobalActor(toEI.getGlobalActor()));
       if (applyTypeToClosureExpr(cs, expr, newFromFuncType)) {
         fromFunc = newFromFuncType->castTo<FunctionType>();
 
@@ -7961,14 +8124,11 @@ Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
     }
   }
 
-  // Unresolved types come up in diagnostics for lvalue and inout types.
-  if (fromType->hasUnresolvedType() || toType->hasUnresolvedType())
-    return cs.cacheType(new (ctx) UnresolvedTypeConversionExpr(expr, toType));
-
-  llvm::errs() << "Unhandled coercion:\n";
-  fromType->dump(llvm::errs());
-  toType->dump(llvm::errs());
-  abort();
+  ABORT([&](auto &out) {
+    out << "Unhandled coercion:\n";
+    fromType->dump(out);
+    toType->dump(out);
+  });
 }
 
 static bool isSelfRefInInitializer(Expr *baseExpr,
@@ -8066,13 +8226,6 @@ Expr *ExprRewriter::convertLiteralInPlace(
     Identifier literalType, DeclName literalFuncName,
     ProtocolDecl *builtinProtocol, DeclName builtinLiteralFuncName,
     Diag<> brokenProtocolDiag, Diag<> brokenBuiltinProtocolDiag) {
-  // If coercing a literal to an unresolved type, we don't try to look up the
-  // witness members, just do it.
-  if (type->is<UnresolvedType>()) {
-    cs.setType(literal, type);
-    return literal;
-  }
-
   // Check whether this literal type conforms to the builtin protocol. If so,
   // initialize via the builtin protocol.
   if (builtinProtocol) {
@@ -8081,7 +8234,7 @@ Expr *ExprRewriter::convertLiteralInPlace(
       // Find the witness that we'll use to initialize the type via a builtin
       // literal.
       auto witness = builtinConformance.getWitnessByName(
-          type->getRValueType(), builtinLiteralFuncName);
+          builtinLiteralFuncName);
       if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
         return nullptr;
 
@@ -8106,7 +8259,7 @@ Expr *ExprRewriter::convertLiteralInPlace(
   if (!literalType.empty()) {
     // Extract the literal type.
     Type builtinLiteralType =
-        conformance.getTypeWitnessByName(type, literalType);
+        conformance.getTypeWitnessByName(literalType);
     if (builtinLiteralType->hasError())
       return nullptr;
 
@@ -8120,7 +8273,7 @@ Expr *ExprRewriter::convertLiteralInPlace(
 
   // Find the witness that we'll use to initialize the literal value.
   auto witness =
-      conformance.getWitnessByName(type->getRValueType(), literalFuncName);
+      conformance.getWitnessByName(literalFuncName);
   if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
     return nullptr;
 
@@ -8222,9 +8375,8 @@ std::pair<Expr *, ArgumentList *> ExprRewriter::buildDynamicCallable(
     auto dictLitProto =
         ctx.getProtocol(KnownProtocolKind::ExpressibleByDictionaryLiteral);
     auto conformance = checkConformance(argumentType, dictLitProto);
-    auto keyType = conformance.getTypeWitnessByName(argumentType, ctx.Id_Key);
-    auto valueType =
-        conformance.getTypeWitnessByName(argumentType, ctx.Id_Value);
+    auto keyType = conformance.getTypeWitnessByName(ctx.Id_Key);
+    auto valueType = conformance.getTypeWitnessByName(ctx.Id_Value);
     SmallVector<Identifier, 4> names;
     SmallVector<Expr *, 4> dictElements;
     for (auto arg : *args) {
@@ -8512,12 +8664,6 @@ Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
 
   // FIXME: Handle unwrapping everywhere else.
 
-  // If this is an UnresolvedType in the system, preserve it.
-  if (cs.getType(fn)->is<UnresolvedType>()) {
-    cs.setType(apply, cs.getType(fn));
-    return apply;
-  }
-
   // We have a type constructor.
   auto metaTy = cs.getType(fn)->castTo<AnyMetatypeType>();
   auto ty = metaTy->getInstanceType();
@@ -8543,25 +8689,22 @@ Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
   auto *ctorLocator =
       cs.getConstraintLocator(locator, {ConstraintLocator::ApplyFunction,
                                         ConstraintLocator::ConstructorMember});
-  auto selected = solution.getOverloadChoiceIfAvailable(ctorLocator);
-  if (!selected) {
-    assert(ty->hasError() || ty->hasUnresolvedType());
-    cs.setType(apply, ty);
-    return apply;
-  }
+  auto selected = solution.getOverloadChoice(ctorLocator);
 
   assert(ty->getNominalOrBoundGenericNominal() || ty->is<DynamicSelfType>() ||
          ty->isExistentialType() || ty->is<ArchetypeType>());
 
   // Consider the constructor decl reference expr 'implicit', but the
   // constructor call expr itself has the apply's 'implicitness'.
-  Expr *declRef = buildMemberRef(fn, /*dotLoc=*/SourceLoc(), *selected,
-                                 DeclNameLoc(fn->getEndLoc()), locator,
-                                 ctorLocator, /*implicit=*/true,
-                                 AccessSemantics::Ordinary);
+  Expr *declRef = buildMemberRef(
+      fn, /*dotLoc=*/SourceLoc(), selected, DeclNameLoc(fn->getEndLoc()),
+      locator, ctorLocator, /*implicit=*/true, AccessSemantics::Ordinary);
   if (!declRef)
     return nullptr;
-  declRef->setImplicit(apply->isImplicit());
+
+  if (!isa<AutoClosureExpr>(declRef))
+    declRef->setImplicit(apply->isImplicit());
+
   apply->setFn(declRef);
 
   // Tail-recur to actually call the constructor.
@@ -8930,7 +9073,7 @@ namespace {
         if (AnyFunctionRef(closure).hasExternalPropertyWrapperParameters()) {
           auto *thunkTy = Rewriter.cs.getType(closure)->castTo<FunctionType>();
           return Action::SkipNode(Rewriter.buildSingleCurryThunk(
-              closure, closure, thunkTy,
+              closure, closure, thunkTy, thunkTy,
               Rewriter.cs.getConstraintLocator(closure)));
         }
 
@@ -9317,23 +9460,26 @@ applySolutionToInitialization(SyntacticElementTarget target, Expr *initializer,
   // If this property has an opaque result type, set the underlying type
   // substitutions based on the initializer.
   if (auto var = resultTarget.getInitializationPattern()->getSingleVar()) {
-    SubstitutionMap substitutions;
-    if (auto opaque = var->getOpaqueResultTypeDecl()) {
-      resultTarget.getAsExpr()->forEachChildExpr([&](Expr *expr) -> Expr * {
-        if (auto coercionExpr = dyn_cast<UnderlyingToOpaqueExpr>(expr)) {
-          auto newSubstitutions =
-              coercionExpr->substitutions.mapReplacementTypesOutOfContext();
-          if (substitutions.empty()) {
-            substitutions = newSubstitutions;
-          } else {
-            assert(substitutions.getCanonical() ==
-                       newSubstitutions.getCanonical());
+    if (!var->getParsedAccessor(AccessorKind::Get)) {
+      if (auto opaque = var->getOpaqueResultTypeDecl()) {
+        SubstitutionMap substitutions;
+
+        resultTarget.getAsExpr()->forEachChildExpr([&](Expr *expr) -> Expr * {
+          if (auto coercionExpr = dyn_cast<UnderlyingToOpaqueExpr>(expr)) {
+            auto newSubstitutions =
+                coercionExpr->substitutions.mapReplacementTypesOutOfContext();
+            if (substitutions.empty()) {
+              substitutions = newSubstitutions;
+            } else {
+              assert(substitutions.getCanonical() ==
+                         newSubstitutions.getCanonical());
+            }
           }
-        }
-        return expr;
-      });
+          return expr;
+        });
 
-      opaque->setUniqueUnderlyingTypeSubstitutions(substitutions);
+        opaque->setUniqueUnderlyingTypeSubstitutions(substitutions);
+      }
     }
   }
 
@@ -9585,7 +9731,6 @@ ExprWalker::rewriteTarget(SyntacticElementTarget target) {
     case CTP_CaseStmt:
     case CTP_ReturnStmt:
     case CTP_ExprPattern:
-    case CTP_ForEachStmt:
     case CTP_ForEachSequence:
     case CTP_YieldByValue:
     case CTP_YieldByReference:
@@ -9882,11 +10027,30 @@ ConstraintSystem::applySolution(Solution &solution,
   {
     const auto &score = solution.getFixedScore();
     if (score.Data[SK_Fix] > numResolvableFixes || score.Data[SK_Hole] > 0) {
-      maybeProduceFallbackDiagnostic(target);
+      maybeProduceFallbackDiagnostic(target.getLoc());
       return std::nullopt;
     }
   }
 
+  // If the score indicates the solution is valid, ensure we don't have any
+  // unresolved types.
+  {
+    auto isValidType = [&](Type ty) {
+      return !ty->hasError() && !ty->hasTypeVariableOrPlaceholder();
+    };
+    for (auto &[_, type] : solution.typeBindings) {
+      ASSERT(isValidType(type) && "type binding has invalid type");
+    }
+    for (auto &[_, type] : solution.nodeTypes) {
+      ASSERT(isValidType(solution.simplifyType(type)) &&
+             "node type has invalid type");
+    }
+    for (auto &[_, type] : solution.keyPathComponentTypes) {
+      ASSERT(isValidType(solution.simplifyType(type)) &&
+             "key path type has invalid type");
+    }
+  }
+
   ExprRewriter rewriter(*this, solution, target, shouldSuppressDiagnostics());
   ExprWalker walker(rewriter);
   auto resultTarget = walker.rewriteTarget(target);
diff --git a/lib/Sema/CSBindings.cpp b/lib/Sema/CSBindings.cpp
index 027d7e50b18d7..69c2db62c6edc 100644
--- a/lib/Sema/CSBindings.cpp
+++ b/lib/Sema/CSBindings.cpp
@@ -31,7 +31,6 @@ using namespace swift;
 using namespace constraints;
 using namespace inference;
 
-
 void ConstraintGraphNode::initBindingSet() {
   ASSERT(!hasBindingSet());
   ASSERT(forRepresentativeVar());
@@ -39,6 +38,12 @@ void ConstraintGraphNode::initBindingSet() {
   Set.emplace(CG.getConstraintSystem(), TypeVar, Potential);
 }
 
+/// Check whether there exists a type that could be implicitly converted
+/// to a given type i.e. is the given type is Double or Optional<..> this
+/// function is going to return true because CGFloat could be converted
+/// to a Double and non-optional value could be injected into an optional.
+static bool hasConversions(Type);
+
 static std::optional<Type> checkTypeOfBinding(TypeVariableType *typeVar,
                                               Type type);
 
@@ -110,7 +115,6 @@ static bool isGenericParameter(TypeVariableType *TypeVar) {
 bool PotentialBinding::isViableForJoin() const {
   return Kind == AllowedBindingKind::Supertypes &&
          !BindingType->hasLValueType() &&
-         !BindingType->hasUnresolvedType() &&
          !BindingType->hasTypeVariable() &&
          !BindingType->hasPlaceholder() &&
          !BindingType->hasUnboundGenericType() &&
@@ -508,7 +512,7 @@ void BindingSet::inferTransitiveBindings() {
           auto bindingTy = binding.BindingType->lookThroughAllOptionalTypes();
 
           Type inferredRootTy;
-          if (isKnownKeyPathType(bindingTy)) {
+          if (bindingTy->isKnownKeyPathType()) {
             // AnyKeyPath doesn't have a root type.
             if (bindingTy->isAnyKeyPath())
               continue;
@@ -716,13 +720,15 @@ bool BindingSet::finalize(bool transitive) {
       if (isValid && !capability)
         return false;
 
+      bool isContextualTypeReadOnly = false;
       // If the key path is sufficiently resolved we can add inferred binding
       // to the set.
       SmallSetVector<PotentialBinding, 4> updatedBindings;
       for (const auto &binding : Bindings) {
         auto bindingTy = binding.BindingType->lookThroughAllOptionalTypes();
 
-        assert(isKnownKeyPathType(bindingTy) || bindingTy->is<FunctionType>());
+        assert(bindingTy->isKnownKeyPathType() ||
+               bindingTy->is<FunctionType>());
 
         // Functions don't have capability so we can simply add them.
         if (auto *fnType = bindingTy->getAs<FunctionType>()) {
@@ -735,19 +741,30 @@ bool BindingSet::finalize(bool transitive) {
           }
 
           updatedBindings.insert(binding.withType(fnType));
+          isContextualTypeReadOnly = true;
+        } else if (!(bindingTy->isWritableKeyPath() ||
+                     bindingTy->isReferenceWritableKeyPath())) {
+          isContextualTypeReadOnly = true;
         }
       }
 
       // Note that even though key path literal maybe be invalid it's
       // still the best course of action to use contextual function type
       // bindings because they allow to propagate type information from
-      // the key path into the context, so key path bindings are addded
+      // the key path into the context, so key path bindings are added
       // only if there is absolutely no other choice.
       if (updatedBindings.empty()) {
         auto rootTy = CS.getKeyPathRootType(keyPath);
 
         // A valid key path literal.
         if (capability) {
+          // Capability inference always results in a maximum mutability
+          // but if context is read-only it can be downgraded to avoid
+          // conversions.
+          if (isContextualTypeReadOnly)
+            capability =
+                std::make_pair(KeyPathMutability::ReadOnly, capability->second);
+
           // Note that the binding is formed using root & value
           // type variables produced during constraint generation
           // because at this point root is already known (otherwise
@@ -1348,7 +1365,31 @@ bool BindingSet::isViable(PotentialBinding &binding, bool isTransitive) {
     if (!existingNTD || NTD != existingNTD)
       continue;
 
-    // FIXME: What is going on here needs to be thoroughly re-evaluated.
+    // What is going on in this method needs to be thoroughly re-evaluated!
+    //
+    // This logic aims to skip dropping bindings if
+    // collection type has conversions i.e. in situations like:
+    //
+    // [$T1] conv $T2
+    // $T2 conv [(Int, String)]
+    // $T2.Element equal $T5.Element
+    //
+    // `$T1` could be bound to `(i: Int, v: String)` after
+    // `$T2` is bound to `[(Int, String)]` which is is a problem
+    // because it means that `$T2` was attempted to early
+    // before the solver had a chance to discover all viable
+    // bindings.
+    //
+    // Let's say existing binding is `[(Int, String)]` and
+    // relation is "exact", in this case there is no point
+    // tracking `[$T1]` because upcasts are only allowed for
+    // subtype and other conversions.
+    if (existing->Kind != AllowedBindingKind::Exact) {
+      if (existingType->isKnownStdlibCollectionType() &&
+          hasConversions(existingType)) {
+        continue;
+      }
+    }
 
     // If new type has a type variable it shouldn't
     // be considered  viable.
@@ -1385,7 +1426,7 @@ static bool hasConversions(Type type) {
     return true;
 
   if (auto *structTy = type->getAs<BoundGenericStructType>()) {
-    if (auto eltTy = structTy->isArrayType()) {
+    if (auto eltTy = structTy->getArrayElementType()) {
       return hasConversions(eltTy);
     } else if (auto pair = ConstraintSystem::isDictionaryType(structTy)) {
       return hasConversions(pair->second);
@@ -1665,7 +1706,7 @@ PotentialBindings::inferFromRelational(ConstraintSystem &CS,
       if (type->isExistentialType()) {
         auto layout = type->getExistentialLayout();
         if (auto superclass = layout.explicitSuperclass) {
-          if (isKnownKeyPathType(superclass)) {
+          if (superclass->isKnownKeyPathType()) {
             type = superclass;
             objectTy = superclass;
           }
@@ -1673,7 +1714,7 @@ PotentialBindings::inferFromRelational(ConstraintSystem &CS,
       }
     }
 
-    if (!(isKnownKeyPathType(objectTy) || objectTy->is<AnyFunctionType>()))
+    if (!(objectTy->isKnownKeyPathType() || objectTy->is<AnyFunctionType>()))
       return std::nullopt;
   }
 
@@ -2145,13 +2186,8 @@ void PotentialBindings::reset() {
   AssociatedCodeCompletionToken = ASTNode();
 }
 
-void PotentialBindings::dump(ConstraintSystem &cs,
-                             TypeVariableType *typeVar,
-                             llvm::raw_ostream &out,
-                             unsigned indent) const {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
-
+void PotentialBindings::dump(ConstraintSystem &cs, TypeVariableType *typeVar,
+                             llvm::raw_ostream &out, unsigned indent) const {
   out << "Potential bindings for ";
   typeVar->getImpl().print(out);
   out << "\n";
@@ -2173,16 +2209,17 @@ void PotentialBindings::dump(ConstraintSystem &cs,
                [](auto lhs, auto rhs) {
                    return lhs.first->getID() < rhs.first->getID();
                });
-    interleave(adjacentVars,
-               [&](std::pair<TypeVariableType *, Constraint *> pair) {
-                 out << pair.first->getString(PO);
-                 if (pair.first->getImpl().getFixedType(/*record=*/nullptr))
-                   out << " (fixed)";
-                 out << " via ";
-                 pair.second->print(out, &cs.getASTContext().SourceMgr, indent,
-                                    /*skipLocator=*/true);
-               },
-               [&out]() { out << ", "; });
+    interleave(
+        adjacentVars,
+        [&](std::pair<TypeVariableType *, Constraint *> pair) {
+          out << pair.first->getString(PrintOptions::forDebugging());
+          if (pair.first->getImpl().getFixedType(/*record=*/nullptr))
+            out << " (fixed)";
+          out << " via ";
+          pair.second->print(out, &cs.getASTContext().SourceMgr, indent,
+                             /*skipLocator=*/true);
+        },
+        [&out]() { out << ", "; });
     out << "] ";
   }
 }
@@ -2266,8 +2303,7 @@ static std::string getCollectionLiteralAsString(KnownProtocolKind KPK) {
 }
 
 void BindingSet::dump(llvm::raw_ostream &out, unsigned indent) const {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
+  PrintOptions PO = PrintOptions::forDebugging();
 
   if (auto typeVar = getTypeVariable()) {
     typeVar->getImpl().print(out);
@@ -2652,8 +2688,11 @@ bool TypeVarBindingProducer::computeNext() {
       // let's have it try `Void` as well because there is an
       // implicit conversion `() -> T` to `() -> Void` and this
       // helps to avoid creating a thunk to support it.
+      // Avoid doing this is we already have a hole binding since
+      // introducing Void will just cause local solution ambiguities.
       if (getLocator()->isLastElement<LocatorPathElt::ClosureResult>() &&
-          binding.Kind == AllowedBindingKind::Supertypes) {
+          binding.Kind == AllowedBindingKind::Supertypes &&
+          !binding.BindingType->isPlaceholder()) {
         auto voidType = CS.getASTContext().TheEmptyTupleType;
         addNewBinding(binding.withSameSource(voidType, BindingKind::Exact));
       }
@@ -2959,8 +2998,7 @@ bool TypeVariableBinding::attempt(ConstraintSystem &cs) const {
 
   if (result.isFailure()) {
     if (cs.isDebugMode()) {
-      PrintOptions PO;
-      PO.PrintTypesForDebugging = true;
+      PrintOptions PO = PrintOptions::forDebugging();
 
       llvm::errs().indent(cs.solverState->getCurrentIndent())
           << "(failed to establish binding " << TypeVar->getString(PO)
diff --git a/lib/Sema/CSDiagnostics.cpp b/lib/Sema/CSDiagnostics.cpp
index 5383ba2ebaeec..0196457639458 100644
--- a/lib/Sema/CSDiagnostics.cpp
+++ b/lib/Sema/CSDiagnostics.cpp
@@ -96,42 +96,12 @@ Type FailureDiagnostic::getRawType(ASTNode node) const {
 
 Type FailureDiagnostic::resolveType(Type rawType, bool reconstituteSugar,
                                     bool wantRValue) const {
-  rawType = rawType.transformRec([&](Type type) -> std::optional<Type> {
-    if (auto *typeVar = type->getAs<TypeVariableType>()) {
-      auto resolvedType = S.simplifyType(typeVar);
-
-      if (!resolvedType->hasUnresolvedType())
-        return resolvedType;
-
-      // If type variable was simplified to an unresolved pack expansion
-      // type, let's examine its original pattern type because it could
-      // contain type variables replaceable with their generic parameter
-      // types.
-      if (auto *expansion = resolvedType->getAs<PackExpansionType>()) {
-        auto *locator = typeVar->getImpl().getLocator();
-        auto *openedExpansionTy =
-            locator->castLastElementTo<LocatorPathElt::PackExpansionType>()
-                .getOpenedType();
-        auto patternType = resolveType(openedExpansionTy->getPatternType());
-        return PackExpansionType::get(patternType, expansion->getCountType());
-      }
-
-      Type GP = typeVar->getImpl().getGenericParameter();
-      return resolvedType->is<UnresolvedType>() && GP
-          ? ErrorType::get(GP)
-          : resolvedType;
-    }
+  rawType = S.simplifyType(rawType);
 
-    if (type->hasElementArchetype()) {
-      auto *env = getDC()->getGenericEnvironmentOfContext();
-      return env->mapElementTypeIntoPackContext(type);
-    }
-
-    if (type->isPlaceholder())
-      return Type(type->getASTContext().TheUnresolvedType);
-
-    return std::nullopt;
-  });
+  if (rawType->hasElementArchetype()) {
+    auto *env = getDC()->getGenericEnvironmentOfContext();
+    rawType = env->mapElementTypeIntoPackContext(rawType);
+  }
 
   if (reconstituteSugar)
     rawType = rawType->reconstituteSugar(/*recursive*/ true);
@@ -183,7 +153,7 @@ StringRef FailureDiagnostic::getEditorPlaceholder(
     llvm::SmallVectorImpl<char> &scratch) const {
   llvm::raw_svector_ostream OS(scratch);
   OS << "<#";
-  if (!ty || ty->is<UnresolvedType>()) {
+  if (!ty || ty->isBareErrorType()) {
     OS << description;
   } else {
     OS << "T##";
@@ -236,6 +206,11 @@ bool FailureDiagnostic::conformsToKnownProtocol(
   return TypeChecker::conformsToKnownProtocol(type, protocol);
 }
 
+bool FallbackDiagnostic::diagnoseAsError() {
+  getConstraintSystem().maybeProduceFallbackDiagnostic(getLoc());
+  return true;
+}
+
 Type RequirementFailure::getOwnerType() const {
   auto anchor = getAnchor();
   // If diagnostic is anchored at assignment expression
@@ -398,6 +373,22 @@ ValueDecl *RequirementFailure::getDeclRef() const {
     }
   }
 
+  if (auto *closure = getAsExpr<ClosureExpr>(getRawAnchor())) {
+    if (auto argElt =
+            getLocator()->getFirstElementAs<LocatorPathElt::TupleElement>()) {
+      auto *param = (*closure->getParameters())[argElt->getIndex()];
+      return getAffectedDeclFromType(getType(param));
+    }
+  }
+
+  // If this is a key path to function conversion, the requirements come
+  // from a key path type implicitly formed by the solver.
+  if (isExpr<KeyPathExpr>(getRawAnchor()) &&
+      getLocator()->isFirstElement<LocatorPathElt::KeyPathType>() &&
+      getOwnerType()->is<FunctionType>()) {
+    return getASTContext().getKeyPathDecl();
+  }
+
   return getAffectedDeclFromType(getOwnerType());
 }
 
@@ -640,7 +631,7 @@ bool MissingConformanceFailure::diagnoseAsError() {
           auto path = fix->getLocator()->getPath();
           SourceRange range;
           simplifyLocator(anchor, path, range);
-          if (anchor && anchor.is<Expr *>())
+          if (anchor && isa<Expr *>(anchor))
             anchors.insert(getAsExpr(anchor));
         }
       }
@@ -671,15 +662,17 @@ bool MissingConformanceFailure::diagnoseAsError() {
     };
 
     // Limit this to `Equatable` and `Comparable` protocols for now.
-    auto *protocol = getRHS()->castTo<ProtocolType>()->getDecl();
-    if (isEnumWithAssociatedValues(getLHS()) &&
-        (protocol->isSpecificProtocol(KnownProtocolKind::Equatable) ||
-         protocol->isSpecificProtocol(KnownProtocolKind::Comparable))) {
-      if (RequirementFailure::diagnoseAsError()) {
-        auto opName = getOperatorName(expr);
-        emitDiagnostic(diag::no_binary_op_overload_for_enum_with_payload,
-                       opName->str());
-        return true;
+    if (auto *protocolTy = getRHS()->getAs<ProtocolType>()) {
+      auto *protocol = protocolTy->getDecl();
+      if (isEnumWithAssociatedValues(getLHS()) &&
+          (protocol->isSpecificProtocol(KnownProtocolKind::Equatable) ||
+           protocol->isSpecificProtocol(KnownProtocolKind::Comparable))) {
+        if (RequirementFailure::diagnoseAsError()) {
+          auto opName = getOperatorName(expr);
+          emitDiagnostic(diag::no_binary_op_overload_for_enum_with_payload,
+                         opName->str());
+          return true;
+        }
       }
     }
   }
@@ -869,7 +862,6 @@ GenericArgumentsMismatchFailure::getDiagnosticFor(
 
   case CTP_CaseStmt:
   case CTP_ThrowStmt:
-  case CTP_ForEachStmt:
   case CTP_ForEachSequence:
   case CTP_ComposedPropertyWrapper:
   case CTP_Unused:
@@ -1114,7 +1106,12 @@ bool GenericArgumentsMismatchFailure::diagnoseAsError() {
   if (!diagnostic)
     return false;
 
-  emitDiagnosticAt(::getLoc(anchor), *diagnostic, fromType, toType);
+  {
+    auto diag =
+        emitDiagnosticAt(::getLoc(anchor), *diagnostic, fromType, toType);
+    (void)tryFixIts(diag);
+  }
+
   emitNotesForMismatches();
   return true;
 }
@@ -1908,7 +1905,6 @@ bool MissingOptionalUnwrapFailure::diagnoseAsError() {
                                                       "#default value#"
                                                       "> }");
         }
-        diag.flush();
 
         offerDefaultValueUnwrapFixIt(varDecl->getDeclContext(), initializer);
         offerForceUnwrapFixIt(initializer);
@@ -1979,7 +1975,7 @@ bool RValueTreatedAsLValueFailure::diagnoseAsError() {
       auto argType = getType(inoutExpr)->getWithoutSpecifierType();
 
       PointerTypeKind ptr;
-      if (argType->isArrayType() && paramType->getAnyPointerElementType(ptr)
+      if (argType->isArray() && paramType->getAnyPointerElementType(ptr)
           && (ptr == PTK_UnsafePointer || ptr == PTK_UnsafeRawPointer)) {
         emitDiagnosticAt(inoutExpr->getLoc(),
                          diag::extra_address_of_unsafepointer, paramType)
@@ -2044,11 +2040,24 @@ bool RValueTreatedAsLValueFailure::diagnoseAsError() {
 }
 
 bool RValueTreatedAsLValueFailure::diagnoseAsNote() {
-  auto overload = getCalleeOverloadChoiceIfAvailable(getLocator());
+  auto *locator = getLocator();
+
+  auto overload = getCalleeOverloadChoiceIfAvailable(locator);
   if (!(overload && overload->choice.isDecl()))
     return false;
 
   auto *decl = overload->choice.getDecl();
+
+  if (locator->isLastElement<LocatorPathElt::ArgumentAttribute>()) {
+    auto argConv = locator->findLast<LocatorPathElt::ApplyArgToParam>();
+    if (!argConv)
+      return false;
+
+    emitDiagnosticAt(decl, diag::candidate_expects_inout_argument,
+                     argConv->getParamIdx() + 1);
+    return true;
+  }
+
   emitDiagnosticAt(decl, diag::candidate_is_not_assignable, decl);
   return true;
 }
@@ -2223,7 +2232,7 @@ bool AssignmentFailure::diagnoseAsError() {
 
       auto type = getType(immutableExpr);
 
-      if (isKnownKeyPathType(type))
+      if (type->isKnownKeyPathType())
         message += " is read-only";
       else if (VD->isCaptureList())
         message += " is an immutable capture";
@@ -2274,7 +2283,7 @@ bool AssignmentFailure::diagnoseAsError() {
 
         if (foundProperty != results.end()) {
           auto startLoc = immutableExpr->getStartLoc();
-          auto *property = *foundProperty;
+          auto *property = cast<VarDecl>(*foundProperty);
           auto selfTy = typeContext->getSelfTypeInContext();
 
           // If we found an instance property, suggest inserting "self.",
@@ -2286,7 +2295,7 @@ bool AssignmentFailure::diagnoseAsError() {
             fixItText = selfTy->getString() + ".";
           }
           emitDiagnosticAt(startLoc, diag::masked_mutable_property, fixItText,
-                           property->getDescriptiveKind(), selfTy)
+                           property, selfTy)
               .fixItInsert(startLoc, fixItText);
         }
       }
@@ -2426,9 +2435,10 @@ AssignmentFailure::resolveImmutableBase(Expr *expr) const {
       const auto &declRef = SE->getDecl();
       if (auto *subscript =
               dyn_cast_or_null<SubscriptDecl>(declRef.getDecl())) {
-        if (isImmutable(subscript))
-          return {expr, OverloadChoice(getType(SE->getBase()), subscript,
-                                       FunctionRefInfo::doubleBaseNameApply())};
+        if (isImmutable(subscript)) {
+          return {expr, OverloadChoice::getDecl(getType(SE->getBase()), subscript,
+                                                FunctionRefInfo::doubleBaseNameApply())};
+        }
       }
     }
 
@@ -2483,8 +2493,8 @@ AssignmentFailure::resolveImmutableBase(Expr *expr) const {
     // If the member isn't settable, then it is the problem: return it.
     if (auto member = dyn_cast<AbstractStorageDecl>(MRE->getMember().getDecl()))
       if (isImmutable(member))
-        return {expr, OverloadChoice(getType(MRE->getBase()), member,
-                                     FunctionRefInfo::singleBaseNameApply())};
+        return {expr, OverloadChoice::getDecl(getType(MRE->getBase()), member,
+                                              FunctionRefInfo::singleBaseNameApply())};
 
     // If we weren't able to resolve a member or if it is mutable, then the
     // problem must be with the base, recurse.
@@ -2504,8 +2514,8 @@ AssignmentFailure::resolveImmutableBase(Expr *expr) const {
   }
 
   if (auto *DRE = dyn_cast<DeclRefExpr>(expr))
-    return {expr, OverloadChoice(Type(), DRE->getDecl(),
-                                 FunctionRefInfo::unappliedBaseName())};
+    return {expr, OverloadChoice::getDecl(DRE->getDecl(),
+                                          FunctionRefInfo::unappliedBaseName())};
 
   // Look through x!
   if (auto *FVE = dyn_cast<ForceValueExpr>(expr))
@@ -2755,7 +2765,7 @@ bool ContextualFailure::diagnoseAsError() {
       }
     }
 
-    if (CTP == CTP_ForEachStmt || CTP == CTP_ForEachSequence) {
+    if (CTP == CTP_ForEachSequence) {
       if (fromType->isAnyExistentialType()) {
         Type constraintType = fromType;
         if (auto existential = constraintType->getAs<ExistentialType>())
@@ -2813,10 +2823,7 @@ bool ContextualFailure::diagnoseAsError() {
     auto params = fnType->getParams();
 
     ParameterListInfo info(
-        params, choice,
-        hasAppliedSelf(overload->choice, [&solution](Type type) {
-          return solution.simplifyType(type);
-        }));
+        params, choice, hasAppliedSelf(solution, overload->choice));
     auto numMissingArgs = llvm::count_if(
         indices(params), [&info](const unsigned paramIdx) -> bool {
           return !info.hasDefaultArgument(paramIdx);
@@ -2957,7 +2964,6 @@ getContextualNilDiagnostic(ContextualTypePurpose CTP) {
   case CTP_CaseStmt:
   case CTP_ThrowStmt:
   case CTP_DiscardStmt:
-  case CTP_ForEachStmt:
   case CTP_ForEachSequence:
   case CTP_YieldByReference:
   case CTP_WrappedProperty:
@@ -3125,7 +3131,7 @@ void ContextualFailure::tryFixIts(InFlightDiagnostic &diagnostic) const {
   if (tryIntegerCastFixIts(diagnostic))
     return;
 
-  if (tryProtocolConformanceFixIt(diagnostic))
+  if (tryProtocolConformanceFixIt())
     return;
 
   if (tryTypeCoercionFixIt(diagnostic))
@@ -3302,7 +3308,7 @@ bool ContextualFailure::diagnoseThrowsTypeMismatch() const {
     if (conformance && toErrorExistential) {
       Type errorType =
           conformance
-              .getTypeWitnessByName(errorCodeType, getASTContext().Id_ErrorType)
+              .getTypeWitnessByName(getASTContext().Id_ErrorType)
               ->getCanonicalType();
       if (errorType) {
         auto diagnostic = emitDiagnostic(diag::cannot_throw_error_code,
@@ -3496,8 +3502,7 @@ bool ContextualFailure::tryTypeCoercionFixIt(
   return false;
 }
 
-bool ContextualFailure::tryProtocolConformanceFixIt(
-    InFlightDiagnostic &diagnostic) const {
+bool ContextualFailure::tryProtocolConformanceFixIt() const {
   auto innermostTyCtx = getDC()->getInnermostTypeContext();
   if (!innermostTyCtx)
     return false;
@@ -3531,8 +3536,6 @@ bool ContextualFailure::tryProtocolConformanceFixIt(
   if (!shouldOfferFixIt)
     return false;
 
-  diagnostic.flush();
-
   // Let's build a list of protocols that the context does not conform to.
   SmallVector<std::string, 8> missingProtoTypeStrings;
   SmallVector<ProtocolDecl *, 8> missingProtocols;
@@ -3565,9 +3568,8 @@ bool ContextualFailure::tryProtocolConformanceFixIt(
 
   // Emit a diagnostic to inform the user that they need to conform to the
   // missing protocols.
-  auto conformanceDiag =
-      emitDiagnostic(diag::assign_protocol_conformance_fix_it, constraint,
-                     nominal->getDescriptiveKind(), fromType);
+  auto conformanceDiag = emitDiagnostic(
+      diag::assign_protocol_conformance_fix_it, constraint, nominal);
   if (!nominal->getInherited().empty()) {
     auto lastInheritedEndLoc = nominal->getInherited().getEndLoc();
     conformanceDiag.fixItInsertAfter(lastInheritedEndLoc, ", " + protoString);
@@ -3584,7 +3586,8 @@ bool ContextualFailure::tryProtocolConformanceFixIt(
     for (auto protocol : missingProtocols) {
       // Create a fake conformance for this type to the given protocol.
       auto conformance = getASTContext().getNormalConformance(
-          nominal->getSelfInterfaceType(), protocol, SourceLoc(), nominal,
+          nominal->getSelfInterfaceType(), protocol, SourceLoc(),
+          /*inheritedTypeRepr=*/nullptr, nominal,
           ProtocolConformanceState::Incomplete, ProtocolConformanceOptions());
 
       // Resolve the conformance to generate fixits.
@@ -3748,7 +3751,6 @@ ContextualFailure::getDiagnosticFor(ContextualTypePurpose context,
     return diag::cannot_match_value_with_pattern;
 
   case CTP_ThrowStmt:
-  case CTP_ForEachStmt:
   case CTP_ForEachSequence:
   case CTP_ComposedPropertyWrapper:
   case CTP_Unused:
@@ -3862,7 +3864,8 @@ bool NonOptionalUnwrapFailure::diagnoseAsError() {
     diagnostic = diag::invalid_force_unwrap;
 
   auto range = getSourceRange();
-  emitDiagnostic(diagnostic, BaseType).highlight(range).fixItRemove(range.End);
+  emitDiagnostic(diagnostic, resolveType(BaseType))
+    .highlight(range).fixItRemove(range.End);
   return true;
 }
 
@@ -3923,14 +3926,14 @@ bool MissingCallFailure::diagnoseAsError() {
 
   if (auto *DRE = getAsExpr<DeclRefExpr>(anchor)) {
     emitDiagnostic(diag::did_not_call_function,
-                   DRE->getDecl()->getBaseIdentifier())
+                   DRE->getDecl()->getBaseName())
         .fixItInsertAfter(insertLoc, "()");
     return true;
   }
 
   if (auto *UDE = getAsExpr<UnresolvedDotExpr>(anchor)) {
     emitDiagnostic(diag::did_not_call_method,
-                   UDE->getName().getBaseIdentifier())
+                   UDE->getName().getBaseName())
         .fixItInsertAfter(insertLoc, "()");
     return true;
   }
@@ -3938,7 +3941,7 @@ bool MissingCallFailure::diagnoseAsError() {
   if (auto *DSCE = getAsExpr<DotSyntaxCallExpr>(anchor)) {
     if (auto *DRE = dyn_cast<DeclRefExpr>(DSCE->getFn())) {
       emitDiagnostic(diag::did_not_call_method,
-                     DRE->getDecl()->getBaseIdentifier())
+                     DRE->getDecl()->getBaseName())
           .fixItInsertAfter(insertLoc, "()");
       return true;
     }
@@ -4064,7 +4067,6 @@ bool SubscriptMisuseFailure::diagnoseAsError() {
   } else {
     diag.fixItReplace(SourceRange(memberExpr->getDotLoc(), memberExpr->getLoc()), "[<#index#>]");
   }
-  diag.flush();
 
   if (auto overload = getOverloadChoiceIfAvailable(locator)) {
     emitDiagnosticAt(overload->choice.getDecl(), diag::kind_declared_here,
@@ -4115,11 +4117,11 @@ void MissingMemberFailure::diagnoseUnsafeCxxMethod(SourceLoc loc,
                                                           scratch);
     };
 
-    auto returnTypeStr = cast<FuncDecl>(found)
-                             ->getResultInterfaceType()
-                             ->getAnyNominal()
-                             ->getName()
-                             .str();
+    auto returnTy =
+        cast<FuncDecl>(found)->getResultInterfaceType()->getAnyNominal();
+    if (!returnTy)
+      continue;
+    auto returnTypeStr = returnTy->getName().str();
 
     auto methodClangLoc = cxxMethod->getLocation();
     auto methodSwiftLoc =
@@ -4450,8 +4452,9 @@ bool MissingMemberFailure::diagnoseAsError() {
       auto &cs = getConstraintSystem();
 
       auto result = cs.performMemberLookup(
-          ConstraintKind::ValueMember, getName().withoutArgumentLabels(),
-          metatypeTy, FunctionRefInfo::doubleBaseNameApply(), getLocator(),
+          ConstraintKind::ValueMember,
+          getName().withoutArgumentLabels(getASTContext()), metatypeTy,
+          FunctionRefInfo::doubleBaseNameApply(), getLocator(),
           /*includeInaccessibleMembers=*/true);
 
       // If there are no `init` members at all produce a tailored
@@ -4769,6 +4772,8 @@ bool InvalidMemberRefOnExistential::diagnoseAsError() {
     case AccessorKind::Modify2:
     case AccessorKind::Address:
     case AccessorKind::MutableAddress:
+    case AccessorKind::Borrow:
+    case AccessorKind::Mutate:
       PD = SD->getIndices()->get(idx);
       break;
     }
@@ -4842,7 +4847,7 @@ bool AllowTypeOrInstanceMemberFailure::diagnoseAsError() {
 
   auto anchor = getAnchor();
 
-  if (!anchor.is<Expr *>())
+  if (!isa<Expr *>(anchor))
     return false;
 
   Expr *expr = findParentExpr(castToExpr(anchor));
@@ -5328,8 +5333,6 @@ bool MissingArgumentsFailure::diagnoseAsError() {
     diag.fixItInsertAfter(getRawAnchor().getEndLoc(), fixIt.str());
   }
 
-  diag.flush();
-
   if (auto selectedOverload = getCalleeOverloadChoiceIfAvailable(locator)) {
     if (auto *decl = selectedOverload->choice.getDeclOrNull()) {
       emitDiagnosticAt(decl, diag::decl_declared_here, decl);
@@ -5648,7 +5651,7 @@ bool MissingArgumentsFailure::diagnoseMissingResultBuilderElement() const {
   auto fixIt = getEditorPlaceholder("result", paramType, scratch);
   auto fixItLoc = call->getStartLoc();
 
-  if (paramType->is<UnresolvedType>()) {
+  if (paramType->isBareErrorType()) {
     emitDiagnostic(diag::result_builder_missing_element,
                    resultBuilder->getName())
         .fixItInsertAfter(fixItLoc, fixIt);
@@ -5697,8 +5700,6 @@ bool MissingArgumentsFailure::diagnoseInvalidTupleDestructuring() const {
     diagnostic.fixItRemove(TE->getLParenLoc()).fixItRemove(TE->getRParenLoc());
   }
 
-  diagnostic.flush();
-
   // Add a note which points to the overload choice location.
   emitDiagnosticAt(decl, diag::decl_declared_here, decl);
   return true;
@@ -5773,7 +5774,7 @@ bool MissingArgumentsFailure::isMisplacedMissingArgument(
   auto argType = solution.simplifyType(solution.getType(unaryArg));
   auto paramType = fnType->getParams()[1].getPlainType();
 
-  if (isExpr<ClosureExpr>(unaryArg) && argType->is<UnresolvedType>()) {
+  if (isExpr<ClosureExpr>(unaryArg) && argType->is<ErrorType>()) {
     auto unwrappedParamTy = paramType->lookThroughAllOptionalTypes();
     if (unwrappedParamTy->is<FunctionType>() || unwrappedParamTy->isAny())
       return true;
@@ -5927,7 +5928,7 @@ bool ClosureParamDestructuringFailure::diagnoseAsError() {
     };
 
     auto isValidType = [](Type resultType) -> bool {
-      return resultType && !resultType->hasUnresolvedType() &&
+      return resultType && !resultType->hasError() &&
              !resultType->hasTypeVariable();
     };
 
@@ -5941,7 +5942,7 @@ bool ClosureParamDestructuringFailure::diagnoseAsError() {
         nameOS << "<#Result#>";
     }
 
-    if (auto stmt = bodyStmts.front().get<Stmt *>()) {
+    if (auto *stmt = cast<Stmt *>(bodyStmts.front())) {
       // If the body is a single expression with implicit return.
       if (isa<ReturnStmt>(stmt) && stmt->isImplicit()) {
         // And there is non-void expected result type,
@@ -6099,8 +6100,6 @@ bool ExtraneousArgumentsFailure::diagnoseAsError() {
       }
     }
 
-    diag.flush();
-
     // If all of the parameters are anonymous, let's point out references
     // to make it explicit where parameters are used in complex closure body,
     // which helps in situations where braces are missing for potential inner
@@ -6378,7 +6377,8 @@ SourceLoc KeyPathSubscriptIndexHashableFailure::getLoc() const {
   auto *locator = getLocator();
 
   if (locator->isKeyPathSubscriptComponent() ||
-      locator->isKeyPathMemberComponent()) {
+      locator->isKeyPathMemberComponent() ||
+      locator->isKeyPathApplyComponent()) {
     auto *KPE = castToExpr<KeyPathExpr>(getAnchor());
     if (auto kpElt = locator->findFirst<LocatorPathElt::KeyPathComponent>())
       return KPE->getComponents()[kpElt->getIndex()].getLoc();
@@ -6390,7 +6390,7 @@ SourceLoc KeyPathSubscriptIndexHashableFailure::getLoc() const {
 bool KeyPathSubscriptIndexHashableFailure::diagnoseAsError() {
   auto *locator = getLocator();
   emitDiagnostic(diag::expr_keypath_arg_or_index_not_hashable,
-                 !locator->isKeyPathMemberComponent(),
+                 !locator->isKeyPathApplyComponent(),
                  resolveType(NonConformingType));
   return true;
 }
@@ -6461,7 +6461,13 @@ bool InvalidMutatingMethodRefInKeyPath::diagnoseAsError() {
 }
 
 bool InvalidAsyncOrThrowsMethodRefInKeyPath::diagnoseAsError() {
-  emitDiagnostic(diag::effectful_keypath_component, getKind(),
+  emitDiagnostic(diag::effectful_keypath_component, getMember(),
+                 isForKeyPathDynamicMemberLookup());
+  return true;
+}
+
+bool InvalidTypeRefInKeyPath::diagnoseAsError() {
+  emitDiagnostic(diag::expr_keypath_type_ref, getMember(),
                  isForKeyPathDynamicMemberLookup());
   return true;
 }
@@ -6521,7 +6527,7 @@ bool ExtraneousReturnFailure::diagnoseAsError() {
 }
 
 bool NotCompileTimeLiteralFailure::diagnoseAsError() {
-  emitDiagnostic(diag::expect_compile_time_const);
+  emitDiagnostic(diag::expect_compile_time_literal);
   return true;
 }
 
@@ -6582,9 +6588,8 @@ bool CollectionElementContextualFailure::diagnoseAsError() {
     // If this is a conversion failure related to binding of `for-each`
     // statement it has to be diagnosed as pattern match if there are
     // holes present in the contextual type.
-    if ((purpose == ContextualTypePurpose::CTP_ForEachStmt ||
-         purpose == ContextualTypePurpose::CTP_ForEachSequence) &&
-        contextualType->hasUnresolvedType()) {
+    if (purpose == ContextualTypePurpose::CTP_ForEachSequence &&
+        contextualType->hasError()) {
       auto diagnostic = emitDiagnostic(
           (contextualType->is<TupleType>() && !eltType->is<TupleType>())
               ? diag::cannot_match_expr_tuple_pattern_with_nontuple_value
@@ -6836,7 +6841,7 @@ void MissingGenericArgumentsFailure::emitGenericSignatureNote(
     return;
 
   auto *GTD = dyn_cast<GenericTypeDecl>(paramDC);
-  if (!GTD || anchor.is<Expr *>())
+  if (!GTD || isa<Expr *>(anchor))
     return;
 
   auto getParamDecl =
@@ -6976,7 +6981,7 @@ SourceLoc SkipUnhandledConstructInResultBuilderFailure::getLoc() const {
   if (auto stmt = unhandled.dyn_cast<Stmt *>())
     return stmt->getStartLoc();
 
-  return unhandled.get<Decl *>()->getLoc();
+  return cast<Decl *>(unhandled)->getLoc();
 }
 
 /// Determine whether the given "if" chain has a missing "else".
@@ -7162,8 +7167,7 @@ bool SkipUnhandledConstructInResultBuilderFailure::diagnoseAsError() {
   }
 
   diagnosePrimary(/*asNote=*/false);
-  emitDiagnosticAt(builder, diag::kind_declname_declared_here,
-                   builder->getDescriptiveKind(), builder->getName());
+  emitDiagnosticAt(builder, diag::decl_declared_here_with_kind, builder);
   return true;
 }
 
@@ -7242,10 +7246,10 @@ bool InvalidTupleSplatWithSingleParameterFailure::diagnoseAsError() {
       name.isSpecial()
           ? emitDiagnosticAt(args->getLoc(),
                              diag::single_tuple_parameter_mismatch_special,
-                             choice->getDescriptiveKind(), paramTy, subsStr)
-          : emitDiagnosticAt(
-                args->getLoc(), diag::single_tuple_parameter_mismatch_normal,
-                choice, paramTy, subsStr);
+                             choice, paramTy, subsStr)
+          : emitDiagnosticAt(args->getLoc(),
+                             diag::single_tuple_parameter_mismatch_normal,
+                             choice, paramTy, subsStr);
 
   auto newLeftParenLoc = args->getStartLoc();
   auto firstArgLabel = args->getLabel(0);
@@ -7453,10 +7457,10 @@ bool ArgumentMismatchFailure::diagnoseAsError() {
 
   // Unresolved key path argument requires a tailored diagnostic
   // that doesn't mention a fallback type - `KeyPath<_, _>`.
-  if (argType->isKeyPath() && !isKnownKeyPathType(paramType)) {
+  if (argType->isKeyPath() && !paramType->isKnownKeyPathType()) {
     auto keyPathTy = argType->castTo<BoundGenericType>();
     auto rootTy = keyPathTy->getGenericArgs()[0];
-    if (rootTy->is<UnresolvedType>()) {
+    if (rootTy->isBareErrorType()) {
       emitDiagnostic(diag::cannot_convert_unresolved_key_path_argument_value,
                      paramType);
       return true;
@@ -7593,7 +7597,7 @@ bool ArgumentMismatchFailure::diagnosePatternMatchingMismatch() const {
   auto rhsType = getType(rhsExpr);
 
   auto diagnostic =
-      lhsType->is<UnresolvedType>()
+      lhsType->isBareErrorType()
           ? emitDiagnostic(
                 diag::cannot_match_unresolved_expr_pattern_with_value, rhsType)
           : emitDiagnostic(diag::cannot_match_expr_pattern_with_value, lhsType,
@@ -7818,7 +7822,7 @@ bool ArgumentMismatchFailure::diagnoseKeyPathAsFunctionResultMismatch() const {
   auto argType = getFromType();
   auto paramType = getToType();
 
-  if (!isKnownKeyPathType(argType))
+  if (!argType->isKnownKeyPathType())
     return false;
 
   auto kpType = argType->castTo<BoundGenericType>();
@@ -8185,6 +8189,20 @@ bool AssignmentTypeMismatchFailure::diagnoseAsNote() {
   return false;
 }
 
+bool NonMetatypeDynamicTypeFailure::diagnoseAsError() {
+  auto instanceTy = getFromType();
+  auto metatypeTy = getToType();
+  if (instanceTy->isBareErrorType()) {
+    emitDiagnostic(diag::cannot_convert_typeof_to_non_metatype, metatypeTy)
+        .highlight(getSourceRange());
+  } else {
+    emitDiagnostic(diag::cannot_convert_metatype_to_non_metatype,
+                   MetatypeType::get(instanceTy), metatypeTy)
+        .highlight(getSourceRange());
+  }
+  return true;
+}
+
 bool MissingContextualBaseInMemberRefFailure::diagnoseAsError() {
   auto *anchor = castToExpr(getAnchor());
   // Member reference could be wrapped into a number of parens
@@ -8252,7 +8270,7 @@ bool UnableToInferClosureParameterType::diagnoseAsError() {
       if (parentExpr) {
         // Missing or invalid member reference in call.
         if (auto *AE = dyn_cast<ApplyExpr>(parentExpr)) {
-          if (getType(AE->getFn())->is<UnresolvedType>())
+          if (getType(AE->getFn())->is<ErrorType>())
             return false;
         }
 
@@ -8442,7 +8460,8 @@ bool MissingQualifierInMemberRefFailure::diagnoseAsError() {
     return true;
   }
 
-  auto qualifier = DC->getParentModule()->getName();
+  auto *module = DC->getParentModule();
+  auto qualifier = module->getName();
 
   emitDiagnostic(diag::member_shadows_global_function, UDE->getName(),
                  methodKind, choice, qualifier);
@@ -8451,7 +8470,7 @@ bool MissingQualifierInMemberRefFailure::diagnoseAsError() {
   namePlusDot.push_back('.');
 
   emitDiagnostic(diag::fix_unqualified_access_top_level_multi, namePlusDot,
-                 choice->getDescriptiveKind(), qualifier)
+                 choice, module)
       .fixItInsert(UDE->getStartLoc(), namePlusDot);
 
   emitDiagnosticAt(choice, diag::decl_declared_here, choice);
@@ -8594,8 +8613,6 @@ void MissingRawRepresentableInitFailure::fixIt(
           .fixItInsert(range.Start, rawReprObjType->getString() + "(rawValue: ")
           .fixItInsertAfter(range.End, ")");
     } else if (valueObjType) {
-      diagnostic.flush();
-
       std::string fixItBefore = RawReprType->getString() + "(rawValue: ";
       std::string fixItAfter;
 
@@ -9242,9 +9259,10 @@ bool NoopCheckedCast::diagnoseForcedCastExpr() const {
   }
 
   if (fromType->isEqual(toType)) {
-    auto castTypeRepr = expr->getCastTypeRepr();
-    emitDiagnostic(diag::forced_downcast_noop, toType)
-        .fixItRemove(SourceRange(diagLoc, castTypeRepr->getSourceRange().End));
+    auto diag = emitDiagnostic(diag::forced_downcast_noop, toType);
+    if (auto castTypeRepr = expr->getCastTypeRepr()) {
+      diag.fixItRemove(SourceRange(diagLoc, castTypeRepr->getSourceRange().End));
+    }
 
   } else {
     emitDiagnostic(diag::forced_downcast_coercion, fromType, toType)
@@ -9609,6 +9627,12 @@ bool IncorrectInlineArrayLiteralCount::diagnoseAsError() {
   return true;
 }
 
+bool TooManyDynamicMemberLookupsFailure::diagnoseAsError() {
+  emitDiagnostic(diag::too_many_dynamic_member_lookups, Name)
+      .highlight(getSourceRange());
+  return true;
+}
+
 bool DisallowedIsolatedConformance::diagnoseAsError() {
   emitDiagnostic(diag::isolated_conformance_with_sendable_simple,
                  conformance->getType(),
diff --git a/lib/Sema/CSDiagnostics.h b/lib/Sema/CSDiagnostics.h
index ff1346f404091..8d50477c0fa99 100644
--- a/lib/Sema/CSDiagnostics.h
+++ b/lib/Sema/CSDiagnostics.h
@@ -210,6 +210,15 @@ class FailureDiagnostic {
                                  llvm::SmallVectorImpl<char> &scratch) const;
 };
 
+/// Emits a fallback diagnostic message if no other error has been emitted.
+class FallbackDiagnostic final : public FailureDiagnostic {
+public:
+  FallbackDiagnostic(const Solution &solution, ConstraintLocator *locator)
+      : FailureDiagnostic(solution, locator) {}
+
+  bool diagnoseAsError() override;
+};
+
 /// Base class for all of the diagnostics related to generic requirement
 /// failures, provides common information like failed requirement,
 /// declaration where such requirement comes from, etc.
@@ -726,7 +735,7 @@ class ContextualFailure : public FailureDiagnostic {
 
   /// Try to add a fix-it to conform the decl context (if it's a type) to the
   /// protocol
-  bool tryProtocolConformanceFixIt(InFlightDiagnostic &diagnostic) const;
+  bool tryProtocolConformanceFixIt() const;
 
 private:
   Type resolve(Type rawType) const {
@@ -1707,9 +1716,10 @@ class KeyPathSubscriptIndexHashableFailure final : public FailureDiagnostic {
   KeyPathSubscriptIndexHashableFailure(const Solution &solution, Type type,
                                        ConstraintLocator *locator)
       : FailureDiagnostic(solution, locator), NonConformingType(type) {
-    assert((locator->isResultOfKeyPathDynamicMemberLookup() ||
-            locator->isKeyPathSubscriptComponent()) ||
-           locator->isKeyPathMemberComponent());
+    assert(locator->isResultOfKeyPathDynamicMemberLookup() ||
+           locator->isKeyPathSubscriptComponent() ||
+           locator->isKeyPathMemberComponent() ||
+           locator->isKeyPathApplyComponent());
   }
 
   SourceLoc getLoc() const override;
@@ -1889,6 +1899,27 @@ class InvalidAsyncOrThrowsMethodRefInKeyPath final
   bool diagnoseAsError() override;
 };
 
+/// Diagnose an attempt to reference a type as a key path component
+/// e.g.
+///
+/// ```swift
+/// struct S {
+///   enum Q {}
+/// }
+///
+/// _ = \S.Type.Q
+/// ```
+class InvalidTypeRefInKeyPath final : public InvalidMemberRefInKeyPath {
+public:
+  InvalidTypeRefInKeyPath(const Solution &solution, ValueDecl *member,
+                          ConstraintLocator *locator)
+      : InvalidMemberRefInKeyPath(solution, member, locator) {
+    assert(isa<TypeDecl>(member));
+  }
+
+  bool diagnoseAsError() override;
+};
+
 /// Diagnose an attempt to reference a member which has a mutating getter as a
 /// key path component e.g.
 ///
@@ -2170,7 +2201,7 @@ class ArgumentMismatchFailure : public ContextualFailure {
                           FixBehavior fixBehavior =
                               FixBehavior::Error)
       : ContextualFailure(solution, argType, paramType, locator, fixBehavior),
-        Info(*getFunctionArgApplyInfo(getLocator())) {}
+        Info(getFunctionArgApplyInfo(getLocator()).value()) {}
 
   bool diagnoseAsError() override;
   bool diagnoseAsNote() override;
@@ -2397,6 +2428,15 @@ class AssignmentTypeMismatchFailure final : public ContextualFailure {
   bool diagnoseMissingConformance() const;
 };
 
+class NonMetatypeDynamicTypeFailure final : public ContextualFailure {
+public:
+  NonMetatypeDynamicTypeFailure(const Solution &solution, Type instanceTy,
+                                Type metatypeTy, ConstraintLocator *locator)
+      : ContextualFailure(solution, instanceTy, metatypeTy, locator) {}
+
+  bool diagnoseAsError() override;
+};
+
 class MissingContextualBaseInMemberRefFailure final : public FailureDiagnostic {
   DeclNameRef MemberName;
 
@@ -3310,6 +3350,17 @@ class IncorrectInlineArrayLiteralCount final : public FailureDiagnostic {
   bool diagnoseAsError() override;
 };
 
+class TooManyDynamicMemberLookupsFailure final : public FailureDiagnostic {
+  DeclNameRef Name;
+
+public:
+  TooManyDynamicMemberLookupsFailure(const Solution &solution, DeclNameRef name,
+                                     ConstraintLocator *locator)
+      : FailureDiagnostic(solution, locator), Name(name) {}
+
+  bool diagnoseAsError() override;
+};
+
 /// Diagnose when an isolated conformance is used in a place where one cannot
 /// be, e.g., due to a Sendable or SendableMetatype requirement on the
 /// corresponding type parameter.
diff --git a/lib/Sema/CSFix.cpp b/lib/Sema/CSFix.cpp
index c1bc66621f789..6c734b8937643 100644
--- a/lib/Sema/CSFix.cpp
+++ b/lib/Sema/CSFix.cpp
@@ -185,9 +185,12 @@ CoerceToCheckedCast *CoerceToCheckedCast::attempt(ConstraintSystem &cs,
                                                   Type fromType, Type toType,
                                                   bool useConditionalCast,
                                                   ConstraintLocator *locator) {
-  // If any of the types has a type variable, don't add the fix.
-  if (fromType->hasTypeVariable() || toType->hasTypeVariable())
+  // If any of the types have type variables or placeholders, don't add the fix.
+  // `typeCheckCheckedCast` doesn't support checking such types.
+  if (fromType->hasTypeVariableOrPlaceholder() ||
+      toType->hasTypeVariableOrPlaceholder()) {
     return nullptr;
+  }
 
   auto anchor = locator->getAnchor();
   if (auto *assignExpr = getAsExpr<AssignExpr>(anchor))
@@ -219,7 +222,7 @@ TreatArrayLiteralAsDictionary *
 TreatArrayLiteralAsDictionary::attempt(ConstraintSystem &cs, Type dictionaryTy,
                                        Type arrayTy,
                                        ConstraintLocator *locator) {
-  if (!arrayTy->isArrayType())
+  if (!arrayTy->isArray())
     return nullptr;
 
   // Determine the ArrayExpr from the locator.
@@ -282,10 +285,30 @@ getConcurrencyFixBehavior(ConstraintSystem &cs, ConstraintKind constraintKind,
   // We can only handle the downgrade for conversions.
   switch (constraintKind) {
   case ConstraintKind::Conversion:
-  case ConstraintKind::ArgumentConversion:
   case ConstraintKind::Subtype:
     break;
 
+  case ConstraintKind::ArgumentConversion: {
+    if (!forSendable)
+      break;
+
+    // Passing a static member reference as an argument needs to be downgraded
+    // to a warning until future major mode to maintain source compatibility for
+    // code with non-Sendable metatypes.
+    if (!cs.getASTContext().LangOpts.isSwiftVersionAtLeast(7)) {
+      auto *argLoc = cs.getConstraintLocator(locator);
+      if (auto *argument = getAsExpr(simplifyLocatorToAnchor(argLoc))) {
+        if (auto overload = cs.findSelectedOverloadFor(
+                argument->getSemanticsProvidingExpr())) {
+          auto *decl = overload->choice.getDeclOrNull();
+          if (decl && decl->isStatic())
+            return FixBehavior::DowngradeToWarning;
+        }
+      }
+    }
+    break;
+  }
+
   default:
     if (!cs.shouldAttemptFixes())
       return std::nullopt;
@@ -1265,6 +1288,10 @@ bool AllowInvalidRefInKeyPath::diagnose(const Solution &solution,
                                                    getLocator());
     return failure.diagnose(asNote);
   }
+  case RefKind::TypeReference: {
+    InvalidTypeRefInKeyPath failure(solution, Member, getLocator());
+    return failure.diagnose(asNote);
+  }
   }
   llvm_unreachable("covered switch");
 }
@@ -1363,6 +1390,11 @@ AllowInvalidRefInKeyPath::forRef(ConstraintSystem &cs, Type baseType,
     return AllowInvalidRefInKeyPath::create(cs, baseType, RefKind::Initializer,
                                             member, locator);
 
+  // Referencing types in key path is not currently allowed.
+  if (isa<TypeDecl>(member))
+    return AllowInvalidRefInKeyPath::create(cs, baseType, RefKind::TypeReference,
+                                            member, locator);
+
   return nullptr;
 }
 
@@ -1764,7 +1796,10 @@ bool IgnoreAssignmentDestinationType::diagnoseForAmbiguity(
   if (!overload)
     return false;
 
-  auto memberName = overload->choice.getName().getBaseName();
+  auto declName = overload->choice.getName();
+  if (!declName)
+    return false;
+
   auto destType = solution.getType(assignment->getDest());
 
   auto &DE = cs.getASTContext().Diags;
@@ -1772,7 +1807,7 @@ bool IgnoreAssignmentDestinationType::diagnoseForAmbiguity(
   // for cases like this instead of using "contextual" one.
   DE.diagnose(assignment->getSrc()->getLoc(),
               diag::no_candidates_match_result_type,
-              memberName.userFacingName(),
+              declName.getBaseName().userFacingName(),
               solution.simplifyType(destType)->getRValueType());
 
   for (auto &entry : commonFixes) {
@@ -1790,6 +1825,21 @@ IgnoreAssignmentDestinationType::create(ConstraintSystem &cs, Type sourceTy,
       IgnoreAssignmentDestinationType(cs, sourceTy, destTy, locator);
 }
 
+IgnoreNonMetatypeDynamicType *
+IgnoreNonMetatypeDynamicType::create(ConstraintSystem &cs, Type instanceTy,
+                                     Type metatypeTy,
+                                     ConstraintLocator *locator) {
+  return new (cs.getAllocator())
+      IgnoreNonMetatypeDynamicType(cs, instanceTy, metatypeTy, locator);
+}
+
+bool IgnoreNonMetatypeDynamicType::diagnose(const Solution &solution,
+                                            bool asNote) const {
+  NonMetatypeDynamicTypeFailure failure(solution, getFromType(), getToType(),
+                                        getLocator());
+  return failure.diagnose(asNote);
+}
+
 bool AllowInOutConversion::diagnose(const Solution &solution,
                                     bool asNote) const {
   InOutConversionFailure failure(solution, getFromType(), getToType(),
@@ -1814,7 +1864,7 @@ ExpandArrayIntoVarargs::attempt(ConstraintSystem &cs, Type argType,
   if (!(argLoc && argLoc->getParameterFlags().isVariadic()))
     return nullptr;
 
-  auto elementType = argType->isArrayType();
+  auto elementType = argType->getArrayElementType();
   if (!elementType)
     return nullptr;
 
@@ -2155,7 +2205,10 @@ AllowKeyPathWithoutComponents::create(ConstraintSystem &cs,
 
 bool IgnoreInvalidResultBuilderBody::diagnose(const Solution &solution,
                                               bool asNote) const {
-  return true; // Already diagnosed by `matchResultBuilder`.
+  // This should already be diagnosed by `matchResultBuilder`, emit a fallback
+  // diagnostic if not.
+  FallbackDiagnostic diag(solution, getLocator());
+  return diag.diagnose(asNote);
 }
 
 IgnoreInvalidResultBuilderBody *
@@ -2166,7 +2219,10 @@ IgnoreInvalidResultBuilderBody::create(ConstraintSystem &cs,
 
 bool IgnoreInvalidASTNode::diagnose(const Solution &solution,
                                     bool asNote) const {
-  return true; // Already diagnosed by the producer of ErrorExpr or ErrorType.
+  // This should already be diagnosed by the producer of ErrorExpr or ErrorType,
+  // emit a fallback diagnostic if not.
+  FallbackDiagnostic diag(solution, getLocator());
+  return diag.diagnose(asNote);
 }
 
 IgnoreInvalidASTNode *IgnoreInvalidASTNode::create(ConstraintSystem &cs,
@@ -2773,6 +2829,18 @@ bool AllowInlineArrayLiteralCountMismatch::diagnose(const Solution &solution,
   return failure.diagnose(asNote);
 }
 
+TooManyDynamicMemberLookups *
+TooManyDynamicMemberLookups::create(ConstraintSystem &cs, DeclNameRef name,
+                                    ConstraintLocator *locator) {
+  return new (cs.getAllocator()) TooManyDynamicMemberLookups(cs, name, locator);
+}
+
+bool TooManyDynamicMemberLookups::diagnose(const Solution &solution,
+                                           bool asNote) const {
+  TooManyDynamicMemberLookupsFailure failure(solution, Name, getLocator());
+  return failure.diagnose(asNote);
+}
+
 IgnoreIsolatedConformance *
 IgnoreIsolatedConformance::create(ConstraintSystem &cs,
                                   ConstraintLocator *locator,
diff --git a/lib/Sema/CSGen.cpp b/lib/Sema/CSGen.cpp
index 83856c133b78f..dab7f314720de 100644
--- a/lib/Sema/CSGen.cpp
+++ b/lib/Sema/CSGen.cpp
@@ -32,6 +32,7 @@
 #include "swift/Sema/ConstraintGraph.h"
 #include "swift/Sema/ConstraintSystem.h"
 #include "swift/Sema/IDETypeChecking.h"
+#include "swift/Sema/PreparedOverload.h"
 #include "swift/Subsystems.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/SetVector.h"
@@ -1019,7 +1020,7 @@ namespace {
                   options);
       SmallVector<OverloadChoice, 4> outerChoices;
       for (auto decl : outerAlternatives) {
-        outerChoices.push_back(OverloadChoice(Type(), decl, functionRefInfo));
+        outerChoices.push_back(OverloadChoice::getDecl(decl, functionRefInfo));
       }
       CS.addValueMemberConstraint(
           baseTy, name, tv, CurDC, functionRefInfo, outerChoices,
@@ -1043,14 +1044,69 @@ namespace {
       auto tv = CS.createTypeVariable(memberLocator,
                                       TVO_CanBindToLValue | TVO_CanBindToNoEscape);
 
-      OverloadChoice choice =
-          OverloadChoice(CS.getType(base), decl, functionRefInfo);
+      auto choice =
+          OverloadChoice::getDecl(CS.getType(base), decl, functionRefInfo);
 
       auto locator = CS.getConstraintLocator(expr, ConstraintLocator::Member);
       CS.addBindOverloadConstraint(tv, choice, locator, CurDC);
       return tv;
     }
 
+    /// Attempt to infer a result type of a subscript reference where
+    /// the base type is either a stdlib Array or a Dictionary type.
+    /// This is a more principled version of the old performance hack
+    /// that used "favored" types deduced by the constraint optimizer
+    /// and is important to maintain pre-existing solver behavior.
+    Type inferCollectionSubscriptResultType(Type baseTy,
+                                            ArgumentList *argumentList) {
+      auto isLValueBase = false;
+      auto baseObjTy = baseTy;
+      if (baseObjTy->is<LValueType>()) {
+        isLValueBase = true;
+        baseObjTy = baseObjTy->getWithoutSpecifierType();
+      }
+
+      auto subscriptResultType = [&isLValueBase](Type valueTy,
+                                                 bool isOptional) -> Type {
+        Type outputTy = isOptional ? OptionalType::get(valueTy) : valueTy;
+        return isLValueBase ? LValueType::get(outputTy) : outputTy;
+      };
+
+      if (auto *argument = argumentList->getUnlabeledUnaryExpr()) {
+        auto argumentTy = CS.getType(argument);
+
+        auto elementTy = baseObjTy->getArrayElementType();
+
+        if (!elementTy)
+          elementTy = baseObjTy->getInlineArrayElementType();
+
+        if (elementTy) {
+          if (auto arraySliceTy =
+                  dyn_cast<ArraySliceType>(baseObjTy.getPointer())) {
+            baseObjTy = arraySliceTy->getDesugaredType();
+          }
+
+          if (argumentTy->isInt() || isExpr<IntegerLiteralExpr>(argument))
+            return subscriptResultType(elementTy, /*isOptional*/ false);
+        } else if (auto dictTy = CS.isDictionaryType(baseObjTy)) {
+          auto [keyTy, valueTy] = *dictTy;
+
+          if (keyTy->isString() &&
+              (isExpr<StringLiteralExpr>(argument) ||
+               isExpr<InterpolatedStringLiteralExpr>(argument)))
+            return subscriptResultType(valueTy, /*isOptional*/ true);
+
+          if (keyTy->isInt() && isExpr<IntegerLiteralExpr>(argument))
+            return subscriptResultType(valueTy, /*isOptional*/ true);
+
+          if (keyTy->isEqual(argumentTy))
+            return subscriptResultType(valueTy, /*isOptional*/ true);
+        }
+      }
+
+      return Type();
+    }
+
     /// Add constraints for a subscript operation.
     Type addSubscriptConstraints(
         Expr *anchor, Type baseTy, ValueDecl *declOrNull, ArgumentList *argList,
@@ -1074,47 +1130,10 @@ namespace {
 
       Type outputTy;
 
-      // For an integer subscript expression on an array slice type, instead of
-      // introducing a new type variable we can easily obtain the element type.
-      if (isa<SubscriptExpr>(anchor)) {
+      // Attempt to infer the result type of a stdlib collection subscript.
+      if (isa<SubscriptExpr>(anchor))
+        outputTy = inferCollectionSubscriptResultType(baseTy, argList);
 
-        auto isLValueBase = false;
-        auto baseObjTy = baseTy;
-        if (baseObjTy->is<LValueType>()) {
-          isLValueBase = true;
-          baseObjTy = baseObjTy->getWithoutSpecifierType();
-        }
-
-        if (auto elementTy = baseObjTy->isArrayType()) {
-
-          if (auto arraySliceTy = 
-                dyn_cast<ArraySliceType>(baseObjTy.getPointer())) {
-            baseObjTy = arraySliceTy->getDesugaredType();
-          }
-
-          if (argList->isUnlabeledUnary() &&
-              isa<IntegerLiteralExpr>(argList->getExpr(0))) {
-
-            outputTy = elementTy;
-            
-            if (isLValueBase)
-              outputTy = LValueType::get(outputTy);
-          }
-        } else if (auto dictTy = CS.isDictionaryType(baseObjTy)) {
-          auto keyTy = dictTy->first;
-          auto valueTy = dictTy->second;
-
-          if (argList->isUnlabeledUnary()) {
-            auto argTy = CS.getType(argList->getExpr(0));
-            if (isFavoredParamAndArg(CS, keyTy, argTy)) {
-              outputTy = OptionalType::get(valueTy);
-              if (isLValueBase)
-                outputTy = LValueType::get(outputTy);
-            }
-          }
-        }
-      }
-      
       if (outputTy.isNull()) {
         outputTy = CS.createTypeVariable(resultLocator,
                                          TVO_CanBindToLValue | TVO_CanBindToNoEscape);
@@ -1143,7 +1162,7 @@ namespace {
       // a known subscript here. This might be cleaner if we split off a new
       // UnresolvedSubscriptExpr from SubscriptExpr.
       if (auto decl = declOrNull) {
-        OverloadChoice choice = OverloadChoice(
+        auto choice = OverloadChoice::getDecl(
             baseTy, decl, FunctionRefInfo::doubleBaseNameApply());
         CS.addBindOverloadConstraint(memberTy, choice, memberLocator,
                                      CurDC);
@@ -1163,11 +1182,13 @@ namespace {
                                   /*trailingClosureMatching=*/std::nullopt,
                                   CurDC, fnLocator);
 
-      Type fixedOutputType =
-          CS.getFixedTypeRecursive(outputTy, /*wantRValue=*/false);
-      if (!fixedOutputType->isTypeVariableOrMember()) {
-        CS.setFavoredType(anchor, fixedOutputType.getPointer());
-        outputTy = fixedOutputType;
+      if (CS.performanceHacksEnabled()) {
+        Type fixedOutputType =
+            CS.getFixedTypeRecursive(outputTy, /*wantRValue=*/false);
+        if (!fixedOutputType->isTypeVariableOrMember()) {
+          CS.setFavoredType(anchor, fixedOutputType.getPointer());
+          outputTy = fixedOutputType;
+        }
       }
 
       return outputTy;
@@ -1177,7 +1198,6 @@ namespace {
     /// component kind.
     Type addApplyConstraints(
         Expr *anchor, Type memberTy, ArgumentList *argList,
-        ConstraintLocator *memberComponentLoc,
         ConstraintLocator *applyComponentLoc,
         SmallVectorImpl<TypeVariableType *> *addedTypeVars = nullptr) {
       // Locators used in this expression.
@@ -1204,7 +1224,7 @@ namespace {
       for (auto index : indices(params)) {
         const auto &param = params[index];
         CS.verifyThatArgumentIsHashable(index, param.getParameterType(),
-                                        memberComponentLoc, loc);
+                                        applyComponentLoc, loc);
       }
 
       // Add the constraint that the index expression's type be convertible
@@ -1609,9 +1629,11 @@ namespace {
             }
           }
 
-          if (!knownType->hasPlaceholder()) {
-            // Set the favored type for this expression to the known type.
-            CS.setFavoredType(E, knownType.getPointer());
+          if (CS.performanceHacksEnabled()) {
+            if (!knownType->hasPlaceholder()) {
+              // Set the favored type for this expression to the known type.
+              CS.setFavoredType(E, knownType.getPointer());
+            }
           }
         }
       }
@@ -1635,9 +1657,9 @@ namespace {
       // resolve it. This records the overload for use later.
       auto tv = CS.createTypeVariable(locator, options);
 
-      OverloadChoice choice =
-          OverloadChoice(Type(), E->getDecl(), E->getFunctionRefInfo());
-      CS.resolveOverload(locator, tv, choice, CurDC);
+      auto choice =
+          OverloadChoice::getDecl(E->getDecl(), E->getFunctionRefInfo());
+      CS.addBindOverloadConstraint(tv, choice, locator, CurDC);
       return tv;
     }
 
@@ -1675,6 +1697,9 @@ namespace {
       // Introduce type variables for unbound generics.
       const auto genericOpener = OpenUnboundGenericType(CS, locator);
       const auto placeholderHandler = HandlePlaceholderType(CS, locator);
+      const auto requirementOpener =
+          OpenGenericTypeRequirements(CS, locator,
+                                      /*preparedOverload*/ nullptr);
 
       // Add a PackElementOf constraint for 'each T' type reprs.
       PackExpansionExpr *elementEnv = nullptr;
@@ -1686,13 +1711,13 @@ namespace {
 
       const auto result = TypeResolution::resolveContextualType(
           repr, CS.DC, options, genericOpener, placeholderHandler,
-          packElementOpener);
+          packElementOpener, requirementOpener);
+      // If we have an error, record a fix and produce a hole for the type.
       if (result->hasError()) {
         CS.recordFix(
             IgnoreInvalidASTNode::create(CS, CS.getConstraintLocator(locator)));
 
-        return CS.createTypeVariable(CS.getConstraintLocator(repr),
-                                     TVO_CanBindToHole);
+        return PlaceholderType::get(CS.getASTContext(), repr);
       }
       // Diagnose top-level usages of placeholder types.
       if (auto *ty = dyn_cast<PlaceholderTypeRepr>(repr->getWithoutParens())) {
@@ -1723,10 +1748,10 @@ namespace {
     }
 
     Type visitTypeValueExpr(TypeValueExpr *E) {
-      auto ty = E->getParamDecl()->getDeclaredInterfaceType();
-      auto paramType = CS.DC->mapTypeIntoContext(ty);
-      E->setParamType(paramType);
-      return E->getParamDecl()->getValueType();
+      auto ty = E->getParamDecl()->getValueType();
+      if (ty->hasError())
+        return recordInvalidNode(E);
+      return ty;
     }
 
     Type visitDotSyntaxBaseIgnoredExpr(DotSyntaxBaseIgnoredExpr *expr) {
@@ -1750,8 +1775,8 @@ namespace {
         if (decls[i]->isInvalid())
           continue;
 
-        OverloadChoice choice =
-            OverloadChoice(Type(), decls[i], expr->getFunctionRefInfo());
+        auto choice =
+            OverloadChoice::getDecl(decls[i], expr->getFunctionRefInfo());
         choices.push_back(choice);
       }
 
@@ -1932,34 +1957,46 @@ namespace {
     void addSpecializationConstraint(ConstraintLocator *locator, Type boundType,
                                      SourceLoc lAngleLoc,
                                      ArrayRef<TypeRepr *> specializationArgs) {
+      auto &ctx = CS.getASTContext();
+
       // Resolve each type.
       SmallVector<Type, 2> specializationArgTypes;
       auto options =
           TypeResolutionOptions(TypeResolverContext::InExpression);
-      for (auto specializationArg : specializationArgs) {
+      ConstraintLocatorBuilder locBuilder(locator);
+      for (auto idx : indices(specializationArgs)) {
+        auto specializationArg = specializationArgs[idx];
+        auto argLocator =
+            locBuilder.withPathElement(LocatorPathElt::GenericArgument(idx));
         PackExpansionExpr *elementEnv = nullptr;
         if (!OuterExpansions.empty()) {
           options |= TypeResolutionFlags::AllowPackReferences;
           elementEnv = OuterExpansions.back();
         }
+        auto alreadyInvalid = specializationArg->isInvalid();
         auto result = TypeResolution::resolveContextualType(
             specializationArg, CurDC, options,
             // Introduce type variables for unbound generics.
-            OpenUnboundGenericType(CS, locator),
-            HandlePlaceholderType(CS, locator),
-            OpenPackElementType(CS, locator, elementEnv));
+            OpenUnboundGenericType(CS, argLocator),
+            HandlePlaceholderType(CS, argLocator),
+            OpenPackElementType(CS, argLocator, elementEnv),
+            OpenGenericTypeRequirements(CS, locator,
+                                        /*preparedOverload*/ nullptr));
         if (result->hasError()) {
-          auto &ctxt = CS.getASTContext();
-          result = PlaceholderType::get(ctxt, specializationArg);
-          ctxt.Diags.diagnose(lAngleLoc,
-                              diag::while_parsing_as_left_angle_bracket);
+          if (!alreadyInvalid) {
+            ctx.Diags.diagnose(lAngleLoc,
+                               diag::while_parsing_as_left_angle_bracket);
+          }
+          CS.recordFix(IgnoreInvalidASTNode::create(
+              CS, CS.getConstraintLocator(argLocator)));
+          result = PlaceholderType::get(ctx, specializationArg);
         }
         specializationArgTypes.push_back(result);
       }
 
       auto constraint = Constraint::create(
           CS, ConstraintKind::ExplicitGenericArguments, boundType,
-          PackType::get(CS.getASTContext(), specializationArgTypes), locator);
+          PackType::get(ctx, specializationArgTypes), locator);
       CS.addUnsolvedConstraint(constraint);
       CS.activateConstraint(constraint);
     }
@@ -2083,8 +2120,10 @@ namespace {
                               CS.getASTContext());
       }
 
-      if (auto favoredTy = CS.getFavoredType(expr->getSubExpr())) {
-        CS.setFavoredType(expr, favoredTy);
+      if (CS.performanceHacksEnabled()) {
+        if (auto favoredTy = CS.getFavoredType(expr->getSubExpr())) {
+          CS.setFavoredType(expr, favoredTy);
+        }
       }
       return CS.getType(expr->getSubExpr());
     }
@@ -2154,18 +2193,28 @@ namespace {
       };
 
       // If a contextual type exists for this expression, apply it directly.
-      if (contextualType && contextualType->isArrayType()) {
+      if (contextualType &&
+          (contextualType->getArrayElementType() ||
+           contextualType->getInlineArrayElementType())) {
         // Now that we know we're actually going to use the type, get the
         // version for use in a constraint.
         contextualType = CS.getContextualType(expr, /*forConstraint=*/true);
         // FIXME: This is the wrong place to be opening the opaque type.
         contextualType = CS.openOpaqueType(
             contextualType, contextualPurpose, locator, /*ownerDecl=*/nullptr);
-        Type arrayElementType = contextualType->isArrayType();
+
+        Type eltType;
+
+        if (contextualType->isArray())
+          eltType = contextualType->getArrayElementType();
+
+        if (contextualType->isInlineArray())
+          eltType = contextualType->getInlineArrayElementType();
+
         CS.addConstraint(ConstraintKind::LiteralConformsTo, contextualType,
                          arrayProto->getDeclaredInterfaceType(),
                          locator);
-        joinElementTypes(arrayElementType);
+        joinElementTypes(eltType);
         return contextualType;
       }
 
@@ -2493,8 +2542,11 @@ namespace {
       Type thrownErrorTy = [&] {
         // Explicitly-specified thrown type.
         if (closure->getExplicitThrownTypeRepr()) {
-          if (Type explicitType = closure->getExplicitThrownType())
-            return explicitType;
+          if (Type explicitType = closure->getExplicitThrownType()) {
+            // The thrown type may have errors, open as placeholders if needed.
+            return CS.replaceInferableTypesWithTypeVars(explicitType,
+                                                        thrownErrorLocator);
+          }
         }
 
         // Explicitly-specified 'throws' without a type is untyped throws.
@@ -2584,14 +2636,8 @@ namespace {
             return FunctionTypeIsolation::forGlobalActor(actorType);
         }
 
-        if (auto *execution =
-                closure->getAttrs().getAttribute<ExecutionAttr>()) {
-          switch (execution->getBehavior()) {
-          case ExecutionKind::Caller:
-            return FunctionTypeIsolation::forNonIsolatedCaller();
-          case ExecutionKind::Concurrent:
-            return FunctionTypeIsolation::forNonIsolated();
-          }
+        if (closure->getAttrs().hasAttribute<ConcurrentAttr>()) {
+          return FunctionTypeIsolation::forNonIsolated();
         }
 
         return FunctionTypeIsolation::forNonIsolated();
@@ -2765,6 +2811,9 @@ namespace {
           // interface type request via `var->getType()` that would
           // attempt to validate `weak` attribute, and produce a
           // diagnostic in the middle of the solver path.
+          //
+          // FIXME: getVarType() is now gone. Is the above still
+          // relevant?
 
           CS.addConstraint(ConstraintKind::OneWayEqual, oneWayVarType,
                            varType, locator);
@@ -3367,11 +3416,13 @@ namespace {
 
       // If we ended up resolving the result type variable to a concrete type,
       // set it as the favored type for this expression.
-      Type fixedType =
-          CS.getFixedTypeRecursive(resultType, /*wantRvalue=*/true);
-      if (!fixedType->isTypeVariableOrMember()) {
-        CS.setFavoredType(expr, fixedType.getPointer());
-        resultType = fixedType;
+      if (CS.performanceHacksEnabled()) {
+        Type fixedType =
+            CS.getFixedTypeRecursive(resultType, /*wantRvalue=*/true);
+        if (!fixedType->isTypeVariableOrMember()) {
+          CS.setFavoredType(expr, fixedType.getPointer());
+          resultType = fixedType;
+        }
       }
 
       return resultType;
@@ -3800,6 +3851,7 @@ namespace {
 
         switch (auto kind = component.getKind()) {
         case KeyPathExpr::Component::Kind::Invalid:
+          CS.recordFix(IgnoreInvalidASTNode::create(CS, memberLocator));
           break;
         case KeyPathExpr::Component::Kind::CodeCompletion:
           // We don't know what the code completion might resolve to, so we are
@@ -3860,11 +3912,8 @@ namespace {
 
         case KeyPathExpr::Component::Kind::UnresolvedApply:
         case KeyPathExpr::Component::Kind::Apply: {
-          auto prevMemberLocator = CS.getConstraintLocator(
-              locator, LocatorPathElt::KeyPathComponent(i - 1));
           base = addApplyConstraints(E, base, component.getArgs(),
-                                     prevMemberLocator, memberLocator,
-                                     &componentTypeVars);
+                                     memberLocator, &componentTypeVars);
           break;
         }
 
@@ -4062,8 +4111,8 @@ namespace {
     }
 
     /// Lookup all macros with the given macro name.
-    SmallVector<OverloadChoice, 1> lookupMacros(Identifier moduleName,
-                                                Identifier macroName,
+    SmallVector<OverloadChoice, 1> lookupMacros(DeclName moduleName,
+                                                DeclName macroName,
                                                 FunctionRefInfo functionRefInfo,
                                                 MacroRoles roles) {
       SmallVector<OverloadChoice, 1> choices;
@@ -4074,7 +4123,7 @@ namespace {
         // logic.
         if (result->isInvalid())
           continue;
-        OverloadChoice choice = OverloadChoice(Type(), result, functionRefInfo);
+        auto choice = OverloadChoice::getDecl(result, functionRefInfo);
         choices.push_back(choice);
       }
 
@@ -4094,8 +4143,8 @@ namespace {
       CS.associateArgumentList(locator, expr->getArgs());
 
       // Look up the macros with this name.
-      auto moduleIdent = expr->getModuleName().getBaseIdentifier();
-      auto macroIdent = expr->getMacroName().getBaseIdentifier();
+      auto moduleIdent = expr->getModuleName().getBaseName();
+      auto macroIdent = expr->getMacroName().getBaseName();
       FunctionRefInfo functionRefInfo = FunctionRefInfo::singleBaseNameApply();
       auto macros = lookupMacros(moduleIdent, macroIdent, functionRefInfo,
                                  expr->getMacroRoles());
@@ -4591,8 +4640,8 @@ generateForEachStmtConstraints(ConstraintSystem &cs, DeclContext *dc,
   // non-`Sendable` state across the isolation boundary. `next()` should
   // inherit the isolation of the caller, but for now, use the opt out.
   if (isAsync) {
-    auto *nonisolated = new (ctx)
-        NonisolatedAttr(/*unsafe=*/true, /*implicit=*/true);
+    auto *nonisolated =
+        NonisolatedAttr::createImplicit(ctx, NonIsolatedModifier::Unsafe);
     makeIteratorVar->getAttrs().add(nonisolated);
   }
 
@@ -4602,8 +4651,9 @@ generateForEachStmtConstraints(ConstraintSystem &cs, DeclContext *dc,
     FuncDecl *makeIterator = isAsync ? ctx.getAsyncSequenceMakeAsyncIterator()
                                      : ctx.getSequenceMakeIterator();
 
-    auto *makeIteratorRef = UnresolvedDotExpr::createImplicit(
-        ctx, sequenceExpr, makeIterator->getName());
+    auto *makeIteratorRef = new (ctx) UnresolvedDotExpr(
+        sequenceExpr, SourceLoc(), DeclNameRef(makeIterator->getName()),
+        DeclNameLoc(stmt->getForLoc()), /*implicit=*/true);
     makeIteratorRef->setFunctionRefInfo(FunctionRefInfo::singleBaseNameApply());
 
     Expr *makeIteratorCall =
@@ -4666,11 +4716,13 @@ generateForEachStmtConstraints(ConstraintSystem &cs, DeclContext *dc,
     TinyPtrVector<Identifier> labels;
     if (nextFn && nextFn->getParameters()->size() == 1)
       labels.push_back(ctx.Id_isolation);
-    auto *nextRef = UnresolvedDotExpr::createImplicit(
-        ctx,
+    auto *makeIteratorVarRef =
         new (ctx) DeclRefExpr(makeIteratorVar, DeclNameLoc(stmt->getForLoc()),
-                              /*Implicit=*/true),
-        nextId, labels);
+                              /*Implicit=*/true);
+    auto *nextRef = new (ctx)
+        UnresolvedDotExpr(makeIteratorVarRef, SourceLoc(),
+                          DeclNameRef(DeclName(ctx, nextId, labels)),
+                          DeclNameLoc(stmt->getForLoc()), /*implicit=*/true);
     nextRef->setFunctionRefInfo(FunctionRefInfo::singleBaseNameApply());
 
     ArgumentList *nextArgs;
@@ -4691,10 +4743,16 @@ generateForEachStmtConstraints(ConstraintSystem &cs, DeclContext *dc,
     }
 
     // Wrap the 'next' call in 'unsafe', if the for..in loop has that
-    // effect.
-    if (stmt->getUnsafeLoc().isValid()) {
-      nextCall = new (ctx) UnsafeExpr(
-          stmt->getUnsafeLoc(), nextCall, Type(), /*implicit=*/true);
+    // effect or if the loop is async (in which case the iterator variable
+    // is nonisolated(unsafe).
+    if (stmt->getUnsafeLoc().isValid() ||
+        (isAsync &&
+         ctx.LangOpts.StrictConcurrencyLevel == StrictConcurrency::Complete)) {
+      SourceLoc loc = stmt->getUnsafeLoc();
+      bool implicit = stmt->getUnsafeLoc().isInvalid();
+      if (loc.isInvalid())
+        loc = stmt->getForLoc();
+      nextCall = new (ctx) UnsafeExpr(loc, nextCall, Type(), implicit);
     }
 
     // The iterator type must conform to IteratorProtocol.
@@ -4765,12 +4823,6 @@ generateForEachPreambleConstraints(ConstraintSystem &cs,
     return std::nullopt;
   target.setPattern(pattern);
 
-  auto contextualPattern = ContextualPattern::forRawPattern(pattern, dc);
-
-  if (TypeChecker::typeCheckPattern(contextualPattern)->hasError()) {
-    return std::nullopt;
-  }
-
   if (isa<PackExpansionExpr>(forEachExpr)) {
     auto *expansion = cast<PackExpansionExpr>(forEachExpr);
 
@@ -4851,41 +4903,39 @@ bool ConstraintSystem::generateConstraints(
             getConstraintLocator(expr, LocatorPathElt::ContextualType(ctp));
       }
 
-      auto getLocator = [&](Type ty) -> ConstraintLocator * {
-        // If we have a placeholder originating from a PlaceholderTypeRepr,
-        // tack that on to the locator.
-        if (auto *placeholderTy = ty->getAs<PlaceholderType>())
-          if (auto *typeRepr = placeholderTy->getOriginator()
-                                          .dyn_cast<TypeRepr *>())
-            return getConstraintLocator(
-                convertTypeLocator,
-                LocatorPathElt::PlaceholderType(typeRepr));
-        return convertTypeLocator;
-      };
-
-      // Substitute type variables in for placeholder types (and unresolved
-      // types, if allowed).
-      if (allowFreeTypeVariables == FreeTypeVariableBinding::UnresolvedType) {
-        convertType = convertType.transformRec([&](Type type) -> std::optional<Type> {
-          if (type->is<UnresolvedType>() || type->is<PlaceholderType>()) {
-            return Type(createTypeVariable(getLocator(type),
-                                           TVO_CanBindToNoEscape |
-                                               TVO_PrefersSubtypeBinding |
-                                               TVO_CanBindToHole));
-          }
-          return std::nullopt;
-        });
-      } else {
-        convertType = convertType.transformRec([&](Type type) -> std::optional<Type> {
-          if (type->is<PlaceholderType>()) {
-            return Type(createTypeVariable(getLocator(type),
-                                           TVO_CanBindToNoEscape |
-                                               TVO_PrefersSubtypeBinding |
-                                               TVO_CanBindToHole));
-          }
-          return std::nullopt;
-        });
-      }
+      // If the contextual type has an error, we can't apply the solution.
+      // Record a fix for an invalid AST node.
+      if (convertType->hasError())
+        recordFix(IgnoreInvalidASTNode::create(*this, convertTypeLocator));
+
+      // Substitute type variables in for placeholder and error types.
+      convertType =
+          convertType.transformRec([&](Type type) -> std::optional<Type> {
+            auto *tyPtr = type.getPointer();
+            // Open a type variable for a placeholder type repr. Note we don't
+            // do this for arbitrary placeholders since they may be existing
+            // holes when e.g generating the constraints for a ReturnStmt in a
+            // closure.
+            if (auto *placeholderTy = dyn_cast<PlaceholderType>(tyPtr)) {
+              auto originator = placeholderTy->getOriginator();
+              auto *typeRepr = originator.dyn_cast<TypeRepr *>();
+              if (!isa_and_nonnull<PlaceholderTypeRepr>(typeRepr))
+                return std::nullopt;
+
+              auto *loc = getConstraintLocator(
+                  convertTypeLocator,
+                  LocatorPathElt::PlaceholderType(typeRepr));
+              return createTypeVariable(loc, TVO_CanBindToNoEscape |
+                                                 TVO_PrefersSubtypeBinding |
+                                                 TVO_CanBindToHole);
+            }
+            // For ErrorTypes we want to eagerly produce a hole since we know
+            // this is where the issue is.
+            if (auto *errTy = dyn_cast<ErrorType>(tyPtr)) {
+              return PlaceholderType::get(getASTContext(), errTy);
+            }
+            return std::nullopt;
+          });
 
       addContextualConversionConstraint(expr, convertType, ctp,
                                         convertTypeLocator);
@@ -4940,10 +4990,6 @@ bool ConstraintSystem::generateConstraints(
           ContextualPattern::forPatternBindingDecl(patternBinding, index);
       Type patternType = TypeChecker::typeCheckPattern(contextualPattern);
 
-      // Fail early if pattern couldn't be type-checked.
-      if (!patternType || patternType->hasError())
-        return true;
-
       auto *init = patternBinding->getInit(index);
 
       if (!init && patternBinding->isDefaultInitializable(index) &&
@@ -5093,7 +5139,16 @@ bool ConstraintSystem::generateConstraints(StmtCondition condition,
 }
 
 void ConstraintSystem::applyPropertyWrapper(
-    Expr *anchor, AppliedPropertyWrapper applied) {
+    Expr *anchor, AppliedPropertyWrapper applied,
+    PreparedOverloadBuilder *preparedOverload) {
+  if (preparedOverload) {
+    ASSERT(PreparingOverload);
+    preparedOverload->appliedPropertyWrapper(applied);
+    return;
+  }
+
+  ASSERT(!PreparingOverload);
+
   appliedPropertyWrappers[anchor].push_back(applied);
 
   if (solverState)
@@ -5114,9 +5169,14 @@ void ConstraintSystem::removePropertyWrapper(Expr *anchor) {
 
 ConstraintSystem::TypeMatchResult
 ConstraintSystem::applyPropertyWrapperToParameter(
-    Type wrapperType, Type paramType, ParamDecl *param, Identifier argLabel,
-    ConstraintKind matchKind, ConstraintLocator *locator,
-    ConstraintLocator *calleeLocator) {
+    Type wrapperType,
+    Type paramType,
+    ParamDecl *param,
+    Identifier argLabel,
+    ConstraintKind matchKind,
+    ConstraintLocator *locator,
+    ConstraintLocator *calleeLocator,
+    PreparedOverloadBuilder *preparedOverload) {
   Expr *anchor = getAsExpr(calleeLocator->getAnchor());
 
   auto recordPropertyWrapperFix = [&](ConstraintFix *fix) -> TypeMatchResult {
@@ -5125,7 +5185,7 @@ ConstraintSystem::applyPropertyWrapperToParameter(
 
     recordAnyTypeVarAsPotentialHole(paramType);
 
-    if (recordFix(fix))
+    if (recordFix(fix, /*impact=*/1, preparedOverload))
       return getTypeMatchFailure(locator);
 
     return getTypeMatchSuccess();
@@ -5152,21 +5212,34 @@ ConstraintSystem::applyPropertyWrapperToParameter(
 
   if (argLabel.hasDollarPrefix()) {
     Type projectionType = computeProjectedValueType(param, wrapperType);
-    addConstraint(matchKind, paramType, projectionType, locator);
+    addConstraint(matchKind, paramType, projectionType, locator,
+                  /*isFavored=*/false,
+                  preparedOverload);
     if (param->hasImplicitPropertyWrapper()) {
       auto wrappedValueType = getType(param->getPropertyWrapperWrappedValueVar());
-      addConstraint(ConstraintKind::PropertyWrapper, projectionType, wrappedValueType,
-                    getConstraintLocator(param));
+      addConstraint(ConstraintKind::PropertyWrapper,
+                    projectionType, wrappedValueType,
+                    getConstraintLocator(param),
+                    /*isFavored=*/false,
+                    preparedOverload);
       setType(param->getPropertyWrapperProjectionVar(), projectionType);
     }
 
-    applyPropertyWrapper(anchor, { wrapperType, PropertyWrapperInitKind::ProjectedValue });
+    applyPropertyWrapper(anchor,
+                         { wrapperType, PropertyWrapperInitKind::ProjectedValue },
+                         preparedOverload);
   } else if (param->hasExternalPropertyWrapper()) {
     Type wrappedValueType = computeWrappedValueType(param, wrapperType);
-    addConstraint(matchKind, paramType, wrappedValueType, locator);
-    setType(param->getPropertyWrapperWrappedValueVar(), wrappedValueType);
-
-    applyPropertyWrapper(anchor, { wrapperType, PropertyWrapperInitKind::WrappedValue });
+    addConstraint(matchKind, paramType, wrappedValueType,
+                  locator,
+                  /*isFavored=*/false,
+                  preparedOverload);
+    setType(param->getPropertyWrapperWrappedValueVar(), wrappedValueType,
+            preparedOverload);
+
+    applyPropertyWrapper(anchor,
+                         { wrapperType, PropertyWrapperInitKind::WrappedValue },
+                         preparedOverload);
   } else {
     return getTypeMatchFailure(locator);
   }
@@ -5175,7 +5248,7 @@ ConstraintSystem::applyPropertyWrapperToParameter(
 }
 
 void ConstraintSystem::optimizeConstraints(Expr *e) {
-  if (getASTContext().TypeCheckerOpts.DisableConstraintSolverPerformanceHacks)
+  if (!performanceHacksEnabled())
     return;
   
   SmallVector<Expr *, 16> linkedExprs;
diff --git a/lib/Sema/CSOptimizer.cpp b/lib/Sema/CSOptimizer.cpp
new file mode 100644
index 0000000000000..c9237dd9cfa0e
--- /dev/null
+++ b/lib/Sema/CSOptimizer.cpp
@@ -0,0 +1,1961 @@
+//===--- CSOptimizer.cpp - Constraint Optimizer ---------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements disjunction and other constraint optimizations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "TypeChecker.h"
+#include "OpenedExistentials.h"
+#include "swift/AST/ConformanceLookup.h"
+#include "swift/AST/ExistentialLayout.h"
+#include "swift/AST/GenericSignature.h"
+#include "swift/Basic/Defer.h"
+#include "swift/Basic/OptionSet.h"
+#include "swift/Sema/ConstraintGraph.h"
+#include "swift/Sema/ConstraintSystem.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/PointerIntPair.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/TinyPtrVector.h"
+#include "llvm/Support/SaveAndRestore.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cstddef>
+#include <functional>
+
+using namespace swift;
+using namespace constraints;
+
+namespace {
+
+struct DisjunctionInfo {
+  /// The score of the disjunction is the highest score from its choices.
+  /// If the score is nullopt it means that the disjunction is not optimizable.
+  std::optional<double> Score;
+
+  /// The highest scoring choices that could be favored when disjunction
+  /// is attempted.
+  llvm::TinyPtrVector<Constraint *> FavoredChoices;
+
+  /// Whether the decisions were based on speculative information
+  /// i.e. literal argument candidates or initializer type inference.
+  bool IsSpeculative;
+
+  DisjunctionInfo() = default;
+  DisjunctionInfo(std::optional<double> score,
+                  ArrayRef<Constraint *> favoredChoices, bool speculative)
+      : Score(score), FavoredChoices(favoredChoices),
+        IsSpeculative(speculative) {}
+
+  static DisjunctionInfo none() { return {std::nullopt, {}, false}; }
+};
+
+class DisjunctionInfoBuilder {
+  std::optional<double> Score;
+  SmallVector<Constraint *, 2> FavoredChoices;
+  bool IsSpeculative;
+
+public:
+  DisjunctionInfoBuilder(std::optional<double> score)
+      : DisjunctionInfoBuilder(score, {}) {}
+
+  DisjunctionInfoBuilder(std::optional<double> score,
+                         ArrayRef<Constraint *> favoredChoices)
+      : Score(score),
+        FavoredChoices(favoredChoices.begin(), favoredChoices.end()),
+        IsSpeculative(false) {}
+
+  void setFavoredChoices(ArrayRef<Constraint *> choices) {
+    FavoredChoices.clear();
+    FavoredChoices.append(choices.begin(), choices.end());
+  }
+
+  void addFavoredChoice(Constraint *constraint) {
+    FavoredChoices.push_back(constraint);
+  }
+
+  void setSpeculative(bool value = true) { IsSpeculative = value; }
+
+  DisjunctionInfo build() { return {Score, FavoredChoices, IsSpeculative}; }
+};
+
+static DeclContext *getDisjunctionDC(Constraint *disjunction) {
+  auto *choice = disjunction->getNestedConstraints()[0];
+  switch (choice->getKind()) {
+  case ConstraintKind::BindOverload:
+  case ConstraintKind::ValueMember:
+  case ConstraintKind::UnresolvedValueMember:
+  case ConstraintKind::ValueWitness:
+    return choice->getDeclContext();
+  default:
+    return nullptr;
+  }
+}
+
+/// Determine whether the given disjunction appears in a context
+/// transformed by a result builder.
+static bool isInResultBuilderContext(ConstraintSystem &cs,
+                                     Constraint *disjunction) {
+  auto *DC = getDisjunctionDC(disjunction);
+  if (!DC)
+    return false;
+
+  do {
+    auto fnContext = AnyFunctionRef::fromDeclContext(DC);
+    if (!fnContext)
+      return false;
+
+    if (cs.getAppliedResultBuilderTransform(*fnContext))
+      return true;
+
+  } while ((DC = DC->getParent()));
+
+  return false;
+}
+
+/// If the given operator disjunction appears in some position
+// inside of a not yet resolved call i.e. `a.b(1 + c(4) - 1)`
+// both `+` and `-` are "in" argument context of `b`.
+static bool isOperatorPassedToUnresolvedCall(ConstraintSystem &cs,
+                                             Constraint *disjunction) {
+  ASSERT(isOperatorDisjunction(disjunction));
+
+  auto *curr = castToExpr(disjunction->getLocator()->getAnchor());
+  while (auto *parent = cs.getParentExpr(curr)) {
+    SWIFT_DEFER { curr = parent; };
+
+    switch (parent->getKind()) {
+    case ExprKind::OptionalEvaluation:
+    case ExprKind::Paren:
+    case ExprKind::Binary:
+    case ExprKind::PrefixUnary:
+    case ExprKind::PostfixUnary:
+      continue;
+
+    // a.b(<<cond>> ? <<operator chain>> : <<...>>)
+    case ExprKind::Ternary: {
+      auto *T = cast<TernaryExpr>(parent);
+      // If the operator is located in the condition it's
+      // not tied to the context.
+      if (T->getCondExpr() == curr)
+        return false;
+
+      // But the branches are connected to the context.
+      continue;
+    }
+
+    // Handles `a(<<operator chain>>), `a[<<operator chain>>]`,
+    // `.a(<<operator chain>>)` etc.
+    case ExprKind::Call: {
+      auto *call = cast<CallExpr>(parent);
+
+      // Type(...)
+      if (isa<TypeExpr>(call->getFn())) {
+        auto *ctorLoc = cs.getConstraintLocator(
+            call, {LocatorPathElt::ApplyFunction(),
+                   LocatorPathElt::ConstructorMember()});
+        return !cs.findSelectedOverloadFor(ctorLoc);
+      }
+
+      // Ignore injected result builder methods like `buildExpression`
+      // and `buildBlock`.
+      if (auto *UDE = dyn_cast<UnresolvedDotExpr>(call->getFn())) {
+        if (isResultBuilderMethodReference(cs.getASTContext(), UDE))
+          return false;
+      }
+
+      return !cs.findSelectedOverloadFor(call->getFn());
+    }
+
+    default:
+      return false;
+    }
+  }
+
+  return false;
+}
+
+// TODO: both `isIntegerType` and `isFloatType` should be available on Type
+// as `isStdlib{Integer, Float}Type`.
+
+static bool isIntegerType(Type type) {
+  return type->isInt() || type->isInt8() || type->isInt16() ||
+         type->isInt32() || type->isInt64() || type->isUInt() ||
+         type->isUInt8() || type->isUInt16() || type->isUInt32() ||
+         type->isUInt64();
+}
+
+static bool isFloatType(Type type) {
+  return type->isFloat() || type->isDouble() || type->isFloat80();
+}
+
+static bool isUnboundArrayType(Type type) {
+  if (auto *UGT = type->getAs<UnboundGenericType>())
+    return UGT->getDecl() == type->getASTContext().getArrayDecl();
+  return false;
+}
+
+static bool isUnboundDictionaryType(Type type) {
+  if (auto *UGT = type->getAs<UnboundGenericType>())
+    return UGT->getDecl() == type->getASTContext().getDictionaryDecl();
+  return false;
+}
+
+static bool isSupportedOperator(Constraint *disjunction) {
+  if (!isOperatorDisjunction(disjunction))
+    return false;
+
+  auto choices = disjunction->getNestedConstraints();
+  auto *decl = getOverloadChoiceDecl(choices.front());
+
+  auto name = decl->getBaseIdentifier();
+  if (name.isArithmeticOperator() || name.isStandardComparisonOperator() ||
+      name.isBitwiseOperator() || name.isNilCoalescingOperator()) {
+    return true;
+  }
+
+  // Operators like &<<, &>>, &+, .== etc.
+  if (llvm::any_of(choices, [](Constraint *choice) {
+        return isSIMDOperator(getOverloadChoiceDecl(choice));
+      })) {
+    return true;
+  }
+
+  return false;
+}
+
+static bool isSupportedSpecialConstructor(ConstructorDecl *ctor) {
+  if (auto *selfDecl = ctor->getImplicitSelfDecl()) {
+    auto selfTy = selfDecl->getInterfaceType();
+    /// Support `Int*`, `Float*` and `Double` initializers since their generic
+    /// overloads are not too complicated.
+    return selfTy && (isIntegerType(selfTy) || isFloatType(selfTy));
+  }
+  return false;
+}
+
+static bool isStandardComparisonOperator(Constraint *disjunction) {
+  auto *choice = disjunction->getNestedConstraints()[0];
+  if (auto *decl = getOverloadChoiceDecl(choice))
+    return decl->isOperator() &&
+           decl->getBaseIdentifier().isStandardComparisonOperator();
+  return false;
+}
+
+static bool isStandardInfixLogicalOperator(Constraint *disjunction) {
+  auto *choice = disjunction->getNestedConstraints()[0];
+  if (auto *decl = getOverloadChoiceDecl(choice))
+    return decl->isOperator() &&
+           decl->getBaseIdentifier().isStandardInfixLogicalOperator();
+  return false;
+}
+
+static bool isArithmeticOperator(ValueDecl *decl) {
+  return decl->isOperator() && decl->getBaseIdentifier().isArithmeticOperator();
+}
+
+/// Generic choices are supported only if they are not complex enough
+/// that would they'd require solving to figure out whether they are a
+/// potential match or not.
+static bool isSupportedGenericOverloadChoice(ValueDecl *decl,
+                                             GenericFunctionType *choiceType) {
+  // Same type requirements cannot be handled because each
+  // candidate-parameter pair is (currently) considered in isolation.
+  if (llvm::any_of(choiceType->getRequirements(), [](const Requirement &req) {
+        switch (req.getKind()) {
+        case RequirementKind::SameType:
+        case RequirementKind::SameShape:
+          return true;
+
+        case RequirementKind::Conformance:
+        case RequirementKind::Superclass:
+        case RequirementKind::Layout:
+          return false;
+        }
+      }))
+    return false;
+
+  // If there are no same-type requirements, allow signatures
+  // that use only concrete types or generic parameters directly
+  // in their parameter positions i.e. `(T, Int)`.
+
+  auto *paramList = decl->getParameterList();
+  if (!paramList)
+    return false;
+
+  return llvm::all_of(paramList->getArray(), [](const ParamDecl *P) {
+    auto paramType = P->getInterfaceType();
+    return paramType->is<GenericTypeParamType>() ||
+           !paramType->hasTypeParameter();
+  });
+}
+
+static bool isSupportedDisjunction(Constraint *disjunction) {
+  auto choices = disjunction->getNestedConstraints();
+
+  if (isOperatorDisjunction(disjunction))
+    return isSupportedOperator(disjunction);
+
+  if (auto *ctor = dyn_cast_or_null<ConstructorDecl>(
+          getOverloadChoiceDecl(choices.front()))) {
+    if (isSupportedSpecialConstructor(ctor))
+      return true;
+  }
+
+  // Non-operator disjunctions are supported only if they don't
+  // have any complex generic choices.
+  return llvm::all_of(choices, [&](Constraint *choice) {
+    if (choice->isDisabled())
+      return true;
+
+    if (choice->getKind() != ConstraintKind::BindOverload)
+      return false;
+
+    if (auto *decl = getOverloadChoiceDecl(choice)) {
+      // Cannot optimize declarations that return IUO because
+      // they form a disjunction over a result type once attempted.
+      if (decl->isImplicitlyUnwrappedOptional())
+        return false;
+
+      auto choiceType = decl->getInterfaceType()->getAs<AnyFunctionType>();
+      if (!choiceType || choiceType->hasError())
+        return false;
+
+      // Non-generic choices are always supported.
+      if (choiceType->is<FunctionType>())
+        return true;
+
+      if (auto *genericFn = choiceType->getAs<GenericFunctionType>())
+        return isSupportedGenericOverloadChoice(decl, genericFn);
+
+      return false;
+    }
+
+    return false;
+  });
+}
+
+/// Determine whether the given overload choice constitutes a
+/// valid choice that would be attempted during normal solving
+/// without any score increases.
+static ValueDecl *isViableOverloadChoice(ConstraintSystem &cs,
+                                         Constraint *constraint,
+                                         ConstraintLocator *locator) {
+  if (constraint->isDisabled())
+    return nullptr;
+
+  if (constraint->getKind() != ConstraintKind::BindOverload)
+    return nullptr;
+
+  auto choice = constraint->getOverloadChoice();
+  auto *decl = choice.getDeclOrNull();
+  if (!decl)
+    return nullptr;
+
+  // Ignore declarations that come from implicitly imported modules
+  // when `MemberImportVisibility` feature is enabled otherwise
+  // we might end up favoring an overload that would be diagnosed
+  // as unavailable later.
+  if (cs.getASTContext().LangOpts.hasFeature(Feature::MemberImportVisibility)) {
+    if (auto *useDC = constraint->getDeclContext()) {
+      if (!useDC->isDeclImported(decl))
+        return nullptr;
+    }
+  }
+
+  // If disjunction choice is unavailable we cannot
+  // do anything with it.
+  if (cs.isDeclUnavailable(decl, locator))
+    return nullptr;
+
+  return decl;
+}
+
+/// Given the type variable that represents a result type of a
+/// function call, check whether that call is to an initializer
+/// and based on that deduce possible type for the result.
+///
+/// @return A type and a flag that indicates whether there
+/// are any viable failable overloads and empty pair if the
+/// type variable isn't a result of an initializer call.
+static llvm::PointerIntPair<Type, 1, bool>
+inferTypeFromInitializerResultType(ConstraintSystem &cs,
+                                   TypeVariableType *typeVar,
+                                   ArrayRef<Constraint *> disjunctions) {
+  assert(typeVar->getImpl().isFunctionResult());
+
+  auto *resultLoc = typeVar->getImpl().getLocator();
+  auto *call = getAsExpr<CallExpr>(resultLoc->getAnchor());
+  if (!call)
+    return {};
+
+  auto *fn = call->getFn()->getSemanticsProvidingExpr();
+
+  Type instanceTy;
+  ConstraintLocator *ctorLocator = nullptr;
+  if (auto *typeExpr = getAsExpr<TypeExpr>(fn)) {
+    instanceTy = cs.getType(typeExpr)->getMetatypeInstanceType();
+    ctorLocator =
+        cs.getConstraintLocator(call, {LocatorPathElt::ApplyFunction(),
+                                       LocatorPathElt::ConstructorMember()});
+  } else if (auto *UDE = getAsExpr<UnresolvedDotExpr>(fn)) {
+    if (!UDE->getName().getBaseName().isConstructor())
+      return {};
+    instanceTy = cs.getType(UDE->getBase())->getMetatypeInstanceType();
+    ctorLocator = cs.getConstraintLocator(UDE, LocatorPathElt::Member());
+  }
+
+  if (!instanceTy || !ctorLocator)
+    return {};
+
+  auto initRef =
+      llvm::find_if(disjunctions, [&ctorLocator](Constraint *disjunction) {
+        return disjunction->getLocator() == ctorLocator;
+      });
+
+  if (initRef == disjunctions.end())
+    return {};
+
+  unsigned numFailable = 0;
+  unsigned total = 0;
+  for (auto *choice : (*initRef)->getNestedConstraints()) {
+    auto *decl = isViableOverloadChoice(cs, choice, ctorLocator);
+    if (!decl || !isa<ConstructorDecl>(decl))
+      continue;
+
+    auto *ctor = cast<ConstructorDecl>(decl);
+    if (ctor->isFailable())
+      ++numFailable;
+
+    ++total;
+  }
+
+  if (numFailable > 0) {
+    // If all of the active choices are failable, produce an optional
+    // type only.
+    if (numFailable == total)
+      return {instanceTy->wrapInOptionalType(), /*hasFailable=*/false};
+    // Otherwise there are two options.
+    return {instanceTy, /*hasFailable*/ true};
+  }
+
+  return {instanceTy, /*hasFailable=*/false};
+}
+
+/// If the given expression represents a chain of operators that have
+/// only declaration/member references and/or literals as arguments,
+/// attempt to deduce a potential type of the chain. For example if
+/// chain has only integral literals it's going to be `Int`, if there
+/// are some floating-point literals mixed in - it's going to be `Double`.
+static Type inferTypeOfArithmeticOperatorChain(ConstraintSystem &cs,
+                                               ASTNode node) {
+  class OperatorChainAnalyzer : public ASTWalker {
+    ASTContext &C;
+    DeclContext *DC;
+    ConstraintSystem &CS;
+
+    llvm::SmallPtrSet<llvm::PointerIntPair<Type, 1>, 2> candidates;
+
+    bool unsupported = false;
+
+    PreWalkResult<Expr *> walkToExprPre(Expr *expr) override {
+      if (isa<BinaryExpr>(expr))
+        return Action::Continue(expr);
+
+      if (isa<PrefixUnaryExpr>(expr) || isa<PostfixUnaryExpr>(expr))
+        return Action::Continue(expr);
+
+      if (isa<ParenExpr>(expr))
+        return Action::Continue(expr);
+
+      // This inference works only with arithmetic operators
+      // because we know the structure of their overloads.
+      if (auto *ODRE = dyn_cast<OverloadedDeclRefExpr>(expr)) {
+        if (auto *choice = ODRE->getDecls().front()) {
+          if (choice->getBaseIdentifier().isArithmeticOperator())
+            return Action::Continue(expr);
+        }
+      }
+
+      if (auto *LE = dyn_cast<LiteralExpr>(expr)) {
+        if (auto *P = TypeChecker::getLiteralProtocol(C, LE)) {
+          if (auto defaultTy = TypeChecker::getDefaultType(P, DC)) {
+            addCandidateType(defaultTy, /*literal=*/true);
+            // String interpolation expressions have `TapExpr`
+            // as their children, no reason to walk them.
+            return Action::SkipChildren(expr);
+          }
+        }
+      }
+
+      if (auto *UDE = dyn_cast<UnresolvedDotExpr>(expr)) {
+        auto memberTy = CS.getType(UDE);
+        if (!memberTy->hasTypeVariable()) {
+          addCandidateType(memberTy, /*literal=*/false);
+          return Action::SkipChildren(expr);
+        }
+      }
+
+      if (auto *DRE = dyn_cast<DeclRefExpr>(expr)) {
+        auto declTy = CS.getType(DRE);
+        if (!declTy->hasTypeVariable()) {
+          addCandidateType(declTy, /*literal=*/false);
+          return Action::SkipChildren(expr);
+        }
+      }
+
+      unsupported = true;
+      return Action::Stop();
+    }
+
+    void addCandidateType(Type type, bool literal) {
+      if (literal) {
+        if (type->isInt()) {
+          // Floating-point types always subsume Int in operator chains.
+          if (llvm::any_of(candidates, [](const auto &candidate) {
+                auto ty = candidate.getPointer();
+                return isFloatType(ty) || ty->isCGFloat();
+              }))
+            return;
+        } else if (isFloatType(type) || type->isCGFloat()) {
+          // A single use of a floating-point literal flips the
+          // type of the entire chain to it.
+          (void)candidates.erase({C.getIntType(), /*literal=*/true});
+        }
+      }
+
+      candidates.insert({type, literal});
+    }
+
+  public:
+    OperatorChainAnalyzer(ConstraintSystem &CS)
+        : C(CS.getASTContext()), DC(CS.DC), CS(CS) {}
+
+    Type chainType() const {
+      if (unsupported)
+        return Type();
+      return candidates.size() != 1 ? Type()
+                                    : (*candidates.begin()).getPointer();
+    }
+  };
+
+  OperatorChainAnalyzer analyzer(cs);
+  node.walk(analyzer);
+
+  return analyzer.chainType();
+}
+
+NullablePtr<Constraint> getApplicableFnConstraint(ConstraintGraph &CG,
+                                                  Constraint *disjunction) {
+  auto *boundVar = disjunction->getNestedConstraints()[0]
+                       ->getFirstType()
+                       ->getAs<TypeVariableType>();
+  if (!boundVar)
+    return nullptr;
+
+  auto constraints =
+      CG.gatherNearbyConstraints(boundVar, [](Constraint *constraint) {
+        return constraint->getKind() == ConstraintKind::ApplicableFunction;
+      });
+
+  if (constraints.size() != 1)
+    return nullptr;
+
+  auto *applicableFn = constraints.front();
+  // Unapplied disjunction could appear as a argument to applicable function,
+  // we are not interested in that.
+  return applicableFn->getSecondType()->isEqual(boundVar) ? applicableFn
+                                                          : nullptr;
+}
+
+void forEachDisjunctionChoice(
+    ConstraintSystem &cs, Constraint *disjunction,
+    llvm::function_ref<void(Constraint *, ValueDecl *decl, FunctionType *)>
+        callback) {
+  for (auto constraint : disjunction->getNestedConstraints()) {
+    auto *decl =
+        isViableOverloadChoice(cs, constraint, disjunction->getLocator());
+    if (!decl)
+      continue;
+
+    Type overloadType = cs.getEffectiveOverloadType(
+        disjunction->getLocator(), constraint->getOverloadChoice(),
+        /*allowMembers=*/true, constraint->getDeclContext());
+
+    if (!overloadType || !overloadType->is<FunctionType>())
+      continue;
+
+    callback(constraint, decl, overloadType->castTo<FunctionType>());
+  }
+}
+
+static OverloadedDeclRefExpr *isOverloadedDeclRef(Constraint *disjunction) {
+  assert(disjunction->getKind() == ConstraintKind::Disjunction);
+
+  auto *locator = disjunction->getLocator();
+  if (locator->getPath().empty())
+    return getAsExpr<OverloadedDeclRefExpr>(locator->getAnchor());
+  return nullptr;
+}
+
+static unsigned numOverloadChoicesMatchingOnArity(OverloadedDeclRefExpr *ODRE,
+                                                  ArgumentList *arguments) {
+  return llvm::count_if(ODRE->getDecls(), [&arguments](auto *choice) {
+    if (auto *paramList = choice->getParameterList())
+      return arguments->size() == paramList->size();
+    return false;
+  });
+}
+
+static bool isVariadicGenericOverload(ValueDecl *choice) {
+  auto genericContext = choice->getAsGenericContext();
+  if (!genericContext)
+    return false;
+
+  auto *GPL = genericContext->getGenericParams();
+  if (!GPL)
+    return false;
+
+  return llvm::any_of(GPL->getParams(), [&](const GenericTypeParamDecl *GP) {
+    return GP->isParameterPack();
+  });
+}
+
+/// This maintains an "old hack" behavior where overloads  of some
+/// `OverloadedDeclRef` calls were favored purely based on number of
+/// argument and (non-defaulted) parameters matching.
+static void findFavoredChoicesBasedOnArity(
+    ConstraintSystem &cs, Constraint *disjunction, ArgumentList *argumentList,
+    llvm::function_ref<void(Constraint *)> favoredChoice) {
+  auto *ODRE = isOverloadedDeclRef(disjunction);
+  if (!ODRE)
+    return;
+
+  if (numOverloadChoicesMatchingOnArity(ODRE, argumentList) > 1)
+    return;
+
+  bool hasVariadicGenerics = false;
+  SmallVector<Constraint *> favored;
+
+  forEachDisjunctionChoice(
+      cs, disjunction,
+      [&](Constraint *choice, ValueDecl *decl, FunctionType *overloadType) {
+        if (decl->getAttrs().hasAttribute<DisfavoredOverloadAttr>())
+          return;
+
+        if (isVariadicGenericOverload(decl)) {
+          hasVariadicGenerics = true;
+          return;
+        }
+
+        if (overloadType->getNumParams() == argumentList->size() ||
+            llvm::count_if(*decl->getParameterList(), [](auto *param) {
+              return !param->isDefaultArgument();
+            }) == argumentList->size())
+          favored.push_back(choice);
+      });
+
+  if (hasVariadicGenerics)
+    return;
+
+  for (auto *choice : favored)
+    favoredChoice(choice);
+}
+
+/// Preserves old behavior where, for unary calls, the solver would not previously
+/// consider choices that didn't match on the number of parameters (regardless of
+/// defaults and variadics) and only exact matches were favored.
+static std::optional<DisjunctionInfo> preserveFavoringOfUnlabeledUnaryArgument(
+    ConstraintSystem &cs, Constraint *disjunction, ArgumentList *argumentList) {
+  if (!argumentList->isUnlabeledUnary())
+    return std::nullopt;
+
+  if (!isExpr<ApplyExpr>(
+          cs.getParentExpr(argumentList->getUnlabeledUnaryExpr())))
+    return std::nullopt;
+
+  // The hack rolled back favoring choices if one of the overloads was a
+  // protocol requirement or variadic generic.
+  //
+  // Note that it doesn't matter whether such overload choices are viable
+  // or not, their presence disabled this "optimization".
+  if (llvm::any_of(disjunction->getNestedConstraints(), [](Constraint *choice) {
+        auto *decl = getOverloadChoiceDecl(choice);
+        if (!decl)
+          return false;
+
+        return isa<ProtocolDecl>(decl->getDeclContext()) ||
+               (!decl->getAttrs().hasAttribute<DisfavoredOverloadAttr>() &&
+                isVariadicGenericOverload(decl));
+      }))
+    return std::nullopt;
+
+  auto ODRE = isOverloadedDeclRef(disjunction);
+  bool preserveFavoringOfUnlabeledUnaryArgument =
+      !ODRE || numOverloadChoicesMatchingOnArity(ODRE, argumentList) < 2;
+
+  if (!preserveFavoringOfUnlabeledUnaryArgument)
+    return std::nullopt;
+
+  auto *argument =
+      argumentList->getUnlabeledUnaryExpr()->getSemanticsProvidingExpr();
+  // The hack operated on "favored" types and only declaration references,
+  // applications, and (dynamic) subscripts had them if they managed to
+  // get an overload choice selected during constraint generation.
+  // It's sometimes possible to infer a type of a literal and an operator
+  // chain, so it should be allowed as well.
+  if (!(isExpr<DeclRefExpr>(argument) || isExpr<ApplyExpr>(argument) ||
+        isExpr<SubscriptExpr>(argument) ||
+        isExpr<DynamicSubscriptExpr>(argument) ||
+        isExpr<LiteralExpr>(argument) || isExpr<BinaryExpr>(argument)))
+    return DisjunctionInfo::none();
+
+  auto argumentType = cs.getType(argument)->getRValueType();
+
+  // For chains like `1 + 2 * 3` it's easy to deduce the type because
+  // we know what literal types are preferred.
+  if (isa<BinaryExpr>(argument)) {
+    auto chainTy = inferTypeOfArithmeticOperatorChain(cs, argument);
+    if (!chainTy)
+      return DisjunctionInfo::none();
+
+    argumentType = chainTy;
+  }
+
+  // Use default type of a literal (when available) to make a guess.
+  // This is what old hack used to do as well.
+  if (auto *LE = dyn_cast<LiteralExpr>(argument)) {
+    auto *P = TypeChecker::getLiteralProtocol(cs.getASTContext(), LE);
+    if (!P)
+      return DisjunctionInfo::none();
+
+    auto defaultTy = TypeChecker::getDefaultType(P, cs.DC);
+    if (!defaultTy)
+      return DisjunctionInfo::none();
+
+    argumentType = defaultTy;
+  }
+
+  ASSERT(argumentType);
+
+  if (argumentType->hasTypeVariable() || argumentType->hasDependentMember())
+    return DisjunctionInfo::none();
+
+  SmallVector<Constraint *, 2> favoredChoices;
+  forEachDisjunctionChoice(
+      cs, disjunction,
+      [&argumentType, &favoredChoices, &argument](
+          Constraint *choice, ValueDecl *decl, FunctionType *overloadType) {
+        if (decl->getAttrs().hasAttribute<DisfavoredOverloadAttr>())
+          return;
+
+        if (overloadType->getNumParams() != 1)
+          return;
+
+        auto &param = overloadType->getParams()[0];
+
+        // Literals are speculative, let's not attempt to apply them too
+        // eagerly.
+        if (!param.getParameterFlags().isNone() &&
+            (isa<LiteralExpr>(argument) || isa<BinaryExpr>(argument)))
+          return;
+
+        if (argumentType->isEqual(param.getPlainType()))
+          favoredChoices.push_back(choice);
+      });
+
+  return DisjunctionInfoBuilder(/*score=*/favoredChoices.empty() ? 0 : 1,
+                                favoredChoices)
+      .build();
+}
+
+} // end anonymous namespace
+
+/// Given a set of disjunctions, attempt to determine
+/// favored choices in the current context.
+static void determineBestChoicesInContext(
+    ConstraintSystem &cs, SmallVectorImpl<Constraint *> &disjunctions,
+    llvm::DenseMap<Constraint *, DisjunctionInfo> &result) {
+  double bestOverallScore = 0.0;
+
+  auto recordResult = [&bestOverallScore, &result](Constraint *disjunction,
+                                                   DisjunctionInfo &&info) {
+    bestOverallScore = std::max(bestOverallScore, info.Score.value_or(0));
+    result.try_emplace(disjunction, info);
+  };
+
+  for (auto *disjunction : disjunctions) {
+    // If this is a compiler synthesized disjunction, mark it as supported
+    // and record all of the previously favored choices. Such disjunctions
+    // include - explicit coercions, IUO references,injected implicit
+    // initializers for CGFloat<->Double conversions and restrictions with
+    // multiple choices.
+    if (disjunction->countFavoredNestedConstraints() > 0) {
+      DisjunctionInfoBuilder info(/*score=*/2.0);
+      for (auto *choice : disjunction->getNestedConstraints()) {
+        if (choice->isFavored())
+          info.addFavoredChoice(choice);
+      }
+      recordResult(disjunction, info.build());
+      continue;
+    }
+
+    auto applicableFn =
+        getApplicableFnConstraint(cs.getConstraintGraph(), disjunction);
+
+    if (applicableFn.isNull()) {
+      auto *locator = disjunction->getLocator();
+      if (auto expr = getAsExpr(locator->getAnchor())) {
+        auto *parentExpr = cs.getParentExpr(expr);
+        // Look through optional evaluation, so
+        // we can cover expressions like `a?.b + 2`.
+        if (isExpr<OptionalEvaluationExpr>(parentExpr))
+          parentExpr = cs.getParentExpr(parentExpr);
+
+        if (parentExpr) {
+          // If this is a chained member reference or a direct operator
+          // argument it could be prioritized since it helps to establish
+          // context for other calls i.e. `(a.)b + 2` if `a` and/or `b`
+          // are disjunctions they should be preferred over `+`.
+          switch (parentExpr->getKind()) {
+          case ExprKind::Binary:
+          case ExprKind::PrefixUnary:
+          case ExprKind::PostfixUnary:
+          case ExprKind::UnresolvedDot: {
+            llvm::SmallVector<Constraint *, 2> favoredChoices;
+            // Favor choices that don't require application.
+            llvm::copy_if(
+                disjunction->getNestedConstraints(),
+                std::back_inserter(favoredChoices), [](Constraint *choice) {
+                  auto *decl = getOverloadChoiceDecl(choice);
+                  return decl &&
+                         !decl->getInterfaceType()->is<AnyFunctionType>();
+                });
+            recordResult(
+                disjunction,
+                DisjunctionInfoBuilder(/*score=*/1.0, favoredChoices).build());
+            continue;
+          }
+
+          default:
+            break;
+          }
+        }
+      }
+
+      continue;
+    }
+
+    auto argFuncType =
+        applicableFn.get()->getFirstType()->getAs<FunctionType>();
+
+    auto argumentList = cs.getArgumentList(applicableFn.get()->getLocator());
+    if (!argumentList)
+      return;
+
+    for (const auto &argument : *argumentList) {
+      if (auto *expr = argument.getExpr()) {
+        // Directly `<#...#>` or has one inside.
+        if (isa<CodeCompletionExpr>(expr) ||
+            cs.containsIDEInspectionTarget(expr))
+          return;
+      }
+    }
+
+    // This maintains an "old hack" behavior where overloads
+    // of `OverloadedDeclRef` calls were favored purely
+    // based on arity of arguments and parameters matching.
+    {
+      llvm::TinyPtrVector<Constraint *> favoredChoices;
+      findFavoredChoicesBasedOnArity(cs, disjunction, argumentList,
+                                     [&favoredChoices](Constraint *choice) {
+                                       favoredChoices.push_back(choice);
+                                     });
+
+      if (!favoredChoices.empty()) {
+        recordResult(
+            disjunction,
+            DisjunctionInfoBuilder(/*score=*/0.01, favoredChoices).build());
+        continue;
+      }
+    }
+
+    // Preserves old behavior where, for unary calls, the solver
+    // would not consider choices that didn't match on the number
+    // of parameters (regardless of defaults) and only exact
+    // matches were favored.
+    if (auto info = preserveFavoringOfUnlabeledUnaryArgument(cs, disjunction,
+                                                             argumentList)) {
+      recordResult(disjunction, std::move(info.value()));
+      continue;
+    }
+
+    if (!isSupportedDisjunction(disjunction))
+      continue;
+
+    SmallVector<FunctionType::Param, 8> argsWithLabels;
+    {
+      argsWithLabels.append(argFuncType->getParams().begin(),
+                            argFuncType->getParams().end());
+      FunctionType::relabelParams(argsWithLabels, argumentList);
+    }
+
+    struct ArgumentCandidate {
+      Type type;
+      // The candidate type is derived from a literal expression.
+      bool fromLiteral : 1;
+      // The candidate type is derived from a call to an
+      // initializer i.e. `Double(...)`.
+      bool fromInitializerCall : 1;
+
+      ArgumentCandidate(Type type, bool fromLiteral = false,
+                        bool fromInitializerCall = false)
+          : type(type), fromLiteral(fromLiteral),
+            fromInitializerCall(fromInitializerCall) {}
+    };
+
+    // Determine whether there are any non-speculative choices
+    // in the given set of candidates. Speculative choices are
+    // literals or types inferred from initializer calls.
+    auto anyNonSpeculativeCandidates =
+        [&](ArrayRef<ArgumentCandidate> candidates) {
+          // If there is only one (non-CGFloat) candidate inferred from
+          // an initializer call we don't consider this a speculation.
+          //
+          // CGFloat inference is always speculative because of the
+          // implicit conversion between Double and CGFloat.
+          if (llvm::count_if(candidates, [&](const auto &candidate) {
+                return candidate.fromInitializerCall &&
+                       !candidate.type->isCGFloat();
+              }) == 1)
+            return true;
+
+          // If there are no non-literal and non-initializer-inferred types
+          // in the list, consider this is a speculation.
+          return llvm::any_of(candidates, [&](const auto &candidate) {
+            return !candidate.fromLiteral && !candidate.fromInitializerCall;
+          });
+        };
+
+    auto anyNonSpeculativeResultTypes = [](ArrayRef<Type> results) {
+      return llvm::any_of(results, [](Type resultTy) {
+        // Double and CGFloat are considered speculative because
+        // there exists an implicit conversion between them and
+        // preference is based on score impact in the overall solution.
+        return !(resultTy->isDouble() || resultTy->isCGFloat());
+      });
+    };
+
+    SmallVector<SmallVector<ArgumentCandidate, 2>, 2>
+        argumentCandidates;
+    argumentCandidates.resize(argFuncType->getNumParams());
+
+    llvm::TinyPtrVector<Type> resultTypes;
+
+    bool hasArgumentCandidates = false;
+    bool isOperator = isOperatorDisjunction(disjunction);
+
+    for (unsigned i = 0, n = argFuncType->getNumParams(); i != n; ++i) {
+      const auto &param = argFuncType->getParams()[i];
+      auto argType = cs.simplifyType(param.getPlainType());
+
+      SmallVector<Type, 2> optionals;
+      // i.e. `??` operator could produce an optional type
+      // so `test(<<something>> ?? 0) could result in an optional
+      // argument that wraps a type variable. It should be possible
+      // to infer bindings from underlying type variable and restore
+      // optionality.
+      if (argType->hasTypeVariable()) {
+        if (auto *typeVar = argType->lookThroughAllOptionalTypes(optionals)
+                                ->getAs<TypeVariableType>())
+          argType = typeVar;
+      }
+
+      SmallVector<ArgumentCandidate, 2> types;
+      if (auto *typeVar = argType->getAs<TypeVariableType>()) {
+        auto bindingSet = cs.getBindingsFor(typeVar);
+
+        // We need to have a notion of "complete" binding set before
+        // we can allow inference from generic parameters and ternary,
+        // otherwise we'd make a favoring decision that might not be
+        // correct i.e. `v ?? (<<cond>> ? nil : o)` where `o` is `Int`.
+        // `getBindingsFor` doesn't currently infer transitive bindings
+        // which means that for a ternary we'd only have a single
+        // binding - `Int` which could lead to favoring overload of
+        // `??` and has non-optional parameter on the right-hand side.
+        if (typeVar->getImpl().getGenericParameter() ||
+            typeVar->getImpl().isTernary())
+          continue;
+
+        auto restoreOptionality = [](Type type, unsigned numOptionals) {
+          for (unsigned i = 0; i != numOptionals; ++i)
+            type = type->wrapInOptionalType();
+          return type;
+        };
+
+        for (const auto &binding : bindingSet.Bindings) {
+          auto type = restoreOptionality(binding.BindingType, optionals.size());
+          types.push_back({type});
+        }
+
+        for (const auto &literal : bindingSet.Literals) {
+          if (literal.second.hasDefaultType()) {
+            // Add primary default type
+            auto type = restoreOptionality(literal.second.getDefaultType(),
+                                           optionals.size());
+            types.push_back({type,
+                             /*fromLiteral=*/true});
+          }
+        }
+
+        // Help situations like `1 + {Double, CGFloat}(...)` by inferring
+        // a type for the second operand of `+` based on a type being
+        // constructed.
+        if (typeVar->getImpl().isFunctionResult()) {
+          auto *resultLoc = typeVar->getImpl().getLocator();
+
+          if (auto type = inferTypeOfArithmeticOperatorChain(
+                  cs, resultLoc->getAnchor())) {
+            types.push_back({type, /*fromLiteral=*/true});
+          }
+
+          auto binding =
+              inferTypeFromInitializerResultType(cs, typeVar, disjunctions);
+
+          if (auto instanceTy = binding.getPointer()) {
+            types.push_back({instanceTy,
+                             /*fromLiteral=*/false,
+                             /*fromInitializerCall=*/true});
+
+            if (binding.getInt())
+              types.push_back({instanceTy->wrapInOptionalType(),
+                               /*fromLiteral=*/false,
+                               /*fromInitializerCall=*/true});
+          }
+        }
+      } else {
+        types.push_back({argType, /*fromLiteral=*/false});
+      }
+
+      argumentCandidates[i].append(types);
+      hasArgumentCandidates |= !types.empty();
+    }
+
+    auto resultType = cs.simplifyType(argFuncType->getResult());
+    if (auto *typeVar = resultType->getAs<TypeVariableType>()) {
+      auto bindingSet = cs.getBindingsFor(typeVar);
+
+      for (const auto &binding : bindingSet.Bindings) {
+        resultTypes.push_back(binding.BindingType);
+      }
+
+      // Infer bindings for each side of a ternary condition.
+      bindingSet.forEachAdjacentVariable(
+          [&cs, &resultTypes](TypeVariableType *adjacentVar) {
+            auto *adjacentLoc = adjacentVar->getImpl().getLocator();
+            // This is one of the sides of a ternary operator.
+            if (adjacentLoc->directlyAt<TernaryExpr>()) {
+              auto adjacentBindings = cs.getBindingsFor(adjacentVar);
+
+              for (const auto &binding : adjacentBindings.Bindings)
+                resultTypes.push_back(binding.BindingType);
+            }
+          });
+    } else {
+      resultTypes.push_back(resultType);
+    }
+
+    // Determine whether all of the argument candidates are speculative (i.e.
+    // literals). This information is going to be used later on when we need to
+    // decide how to score a matching choice.
+    bool onlySpeculativeArgumentCandidates =
+        hasArgumentCandidates &&
+        llvm::none_of(
+            indices(argFuncType->getParams()), [&](const unsigned argIdx) {
+              return anyNonSpeculativeCandidates(argumentCandidates[argIdx]);
+            });
+
+    bool canUseContextualResultTypes =
+        isOperator && !isStandardComparisonOperator(disjunction);
+
+    // Match arguments to the given overload choice.
+    auto matchArguments = [&](OverloadChoice choice, FunctionType *overloadType)
+			-> std::optional<MatchCallArgumentResult> {
+      auto *decl = choice.getDeclOrNull();
+      assert(decl);
+
+      auto hasAppliedSelf =
+          decl->hasCurriedSelf() &&
+          doesMemberRefApplyCurriedSelf(choice.getBaseType(), decl);
+
+      ParameterListInfo paramListInfo(overloadType->getParams(), decl,
+                                      hasAppliedSelf);
+
+      MatchCallArgumentListener listener;
+      return matchCallArguments(argsWithLabels, overloadType->getParams(),
+                                paramListInfo,
+                                argumentList->getFirstTrailingClosureIndex(),
+                                /*allow fixes*/ false, listener, std::nullopt);
+    };
+
+    // Determine whether the candidate type is a subclass of the superclass
+    // type.
+    std::function<bool(Type, Type)> isSubclassOf = [&](Type candidateType,
+                                                       Type superclassType) {
+      // Conversion from a concrete type to its existential value.
+      if (superclassType->isExistentialType() && !superclassType->isAny()) {
+        auto layout = superclassType->getExistentialLayout();
+
+        if (auto layoutConstraint = layout.getLayoutConstraint()) {
+          if (layoutConstraint->isClass() &&
+              !(candidateType->isClassExistentialType() ||
+                candidateType->mayHaveSuperclass()))
+            return false;
+        }
+
+        if (layout.explicitSuperclass &&
+            !isSubclassOf(candidateType, layout.explicitSuperclass))
+          return false;
+
+        return llvm::all_of(layout.getProtocols(), [&](ProtocolDecl *P) {
+          if (auto superclass = P->getSuperclassDecl()) {
+            if (!isSubclassOf(candidateType,
+                              superclass->getDeclaredInterfaceType()))
+              return false;
+          }
+
+          auto result = TypeChecker::containsProtocol(candidateType, P,
+                                                      /*allowMissing=*/false);
+          return result.first || result.second;
+        });
+      }
+
+      if (auto *selfType = candidateType->getAs<DynamicSelfType>()) {
+        candidateType = selfType->getSelfType();
+      }
+
+      if (auto *archetypeType = candidateType->getAs<ArchetypeType>()) {
+        candidateType = archetypeType->getSuperclass();
+        if (!candidateType)
+          return false;
+      }
+
+      auto *subclassDecl = candidateType->getClassOrBoundGenericClass();
+      auto *superclassDecl = superclassType->getClassOrBoundGenericClass();
+
+      if (!(subclassDecl && superclassDecl))
+        return false;
+
+      return superclassDecl->isSuperclassOf(subclassDecl);
+    };
+
+    enum class MatchFlag {
+      OnParam = 0x01,
+      Literal = 0x02,
+      ExactOnly = 0x04,
+      DisableCGFloatDoubleConversion = 0x08,
+      StringInterpolation = 0x10,
+    };
+
+    using MatchOptions = OptionSet<MatchFlag>;
+
+    // Perform a limited set of checks to determine whether the candidate
+    // could possibly match the parameter type:
+    //
+    // - Equality
+    // - Protocol conformance(s)
+    // - Optional injection
+    // - Superclass conversion
+    // - Array-to-pointer conversion
+    // - Value to existential conversion
+    // - Existential opening
+    // - Exact match on top-level types
+    //
+    // In situations when it's not possible to determine whether a candidate
+    // type matches a parameter type (i.e. when partially resolved generic
+    // types are matched) this function is going to produce \c std::nullopt
+    // instead of `0` that indicates "not a match".
+    std::function<std::optional<double>(GenericSignature, ValueDecl *,
+                                        std::optional<unsigned>, Type, Type,
+                                        MatchOptions)>
+        scoreCandidateMatch =
+            [&](GenericSignature genericSig, ValueDecl *choice,
+                std::optional<unsigned> paramIdx, Type candidateType,
+                Type paramType, MatchOptions options) -> std::optional<double> {
+      auto areEqual = [&](Type a, Type b) {
+        return a->getDesugaredType()->isEqual(b->getDesugaredType());
+      };
+
+      auto isCGFloatDoubleConversionSupported = [&options]() {
+        // CGFloat <-> Double conversion is supposed only while
+        // match argument candidates to parameters.
+        return options.contains(MatchFlag::OnParam) &&
+               !options.contains(MatchFlag::DisableCGFloatDoubleConversion);
+      };
+
+      // Allow CGFloat -> Double widening conversions between
+      // candidate argument types and parameter types. This would
+      // make sure that Double is always preferred over CGFloat
+      // when using literals and ranking supported disjunction
+      // choices. Narrowing conversion (Double -> CGFloat) should
+      // be delayed as much as possible.
+      if (isCGFloatDoubleConversionSupported()) {
+        if (candidateType->isCGFloat() && paramType->isDouble()) {
+          return options.contains(MatchFlag::Literal) ? 0.2 : 0.9;
+        }
+      }
+
+      if (options.contains(MatchFlag::ExactOnly)) {
+        // If an exact match is requested favor only `[...]` to `Array<...>`
+        // since everything else is going to increase to score.
+        if (options.contains(MatchFlag::Literal)) {
+          if (isUnboundArrayType(candidateType))
+            return paramType->isArray() ? 0.3 : 0;
+
+          if (isUnboundDictionaryType(candidateType))
+            return cs.isDictionaryType(paramType) ? 0.3 : 0;
+        }
+
+        if (!areEqual(candidateType, paramType))
+          return 0;
+        return options.contains(MatchFlag::Literal) ? 0.3 : 1;
+      }
+
+      // Exact match between candidate and parameter types.
+      if (areEqual(candidateType, paramType)) {
+        return options.contains(MatchFlag::Literal) ? 0.3 : 1;
+      }
+
+      if (options.contains(MatchFlag::Literal)) {
+        if (paramType->hasTypeParameter() ||
+            paramType->isAnyExistentialType()) {
+          // Attempt to match literal default to generic parameter.
+          // This helps to determine whether there are any generic
+          // overloads that are a possible match.
+          auto score =
+              scoreCandidateMatch(genericSig, choice, paramIdx, candidateType,
+                                  paramType, options - MatchFlag::Literal);
+          if (score == 0)
+            return 0;
+
+          // Optional injection lowers the score for operators to match
+          // pre-optimizer behavior.
+          return choice->isOperator() && paramType->getOptionalObjectType()
+                      ? 0.2
+                      : 0.3;
+        } else {
+          // Integer and floating-point literals can match any parameter
+          // type that conforms to `ExpressibleBy{Integer, Float}Literal`
+          // protocol. Since this assessment is done in isolation we don't
+          // lower the score even though this would be a non-default binding
+          // for a literal.
+          if (candidateType->isInt() &&
+              TypeChecker::conformsToKnownProtocol(
+                  paramType, KnownProtocolKind::ExpressibleByIntegerLiteral))
+            return 0.3;
+
+          if (candidateType->isDouble() &&
+              TypeChecker::conformsToKnownProtocol(
+                  paramType, KnownProtocolKind::ExpressibleByFloatLiteral))
+            return 0.3;
+
+          if (candidateType->isBool() &&
+              TypeChecker::conformsToKnownProtocol(
+                  paramType, KnownProtocolKind::ExpressibleByBooleanLiteral))
+            return 0.3;
+
+          if (candidateType->isString()) {
+            auto literalProtocol =
+                options.contains(MatchFlag::StringInterpolation)
+                    ? KnownProtocolKind::ExpressibleByStringInterpolation
+                    : KnownProtocolKind::ExpressibleByStringLiteral;
+
+            if (TypeChecker::conformsToKnownProtocol(paramType,
+                                                     literalProtocol))
+              return 0.3;
+          }
+
+          auto &ctx = cs.getASTContext();
+
+          // Check if the other side conforms to `ExpressibleByArrayLiteral`
+          // protocol (in some way). We want an overly optimistic result
+          // here to avoid under-favoring.
+          if (candidateType->isArray() &&
+              checkConformanceWithoutContext(
+                  paramType,
+                  ctx.getProtocol(KnownProtocolKind::ExpressibleByArrayLiteral),
+                  /*allowMissing=*/true))
+            return 0.3;
+
+          // Check if the other side conforms to
+          // `ExpressibleByDictionaryLiteral` protocol (in some way).
+          // We want an overly optimistic result here to avoid under-favoring.
+          if (candidateType->isDictionary() &&
+              checkConformanceWithoutContext(
+                  paramType,
+                  ctx.getProtocol(
+                      KnownProtocolKind::ExpressibleByDictionaryLiteral),
+                  /*allowMissing=*/true))
+            return 0.3;
+        }
+
+        return 0;
+      }
+
+      // Check whether match would require optional injection.
+      {
+        SmallVector<Type, 2> candidateOptionals;
+        SmallVector<Type, 2> paramOptionals;
+
+        candidateType =
+            candidateType->lookThroughAllOptionalTypes(candidateOptionals);
+        paramType = paramType->lookThroughAllOptionalTypes(paramOptionals);
+
+        if (!candidateOptionals.empty() || !paramOptionals.empty()) {
+          auto requiresOptionalInjection = [&]() {
+            return paramOptionals.size() > candidateOptionals.size();
+          };
+
+          // Can match i.e. Int? to Int or T to Int?
+          if ((paramOptionals.empty() &&
+               paramType->is<GenericTypeParamType>()) ||
+              paramOptionals.size() >= candidateOptionals.size()) {
+            auto score = scoreCandidateMatch(genericSig, choice, paramIdx,
+                                             candidateType, paramType, options);
+
+            if (score > 0) {
+              // Injection lowers the score slightly to comply with
+              // old behavior where exact matches on operator parameter
+              // types were always preferred.
+              if (choice->isOperator() && requiresOptionalInjection())
+                return score.value() - 0.1;
+            }
+
+            return score;
+          }
+
+          // Optionality mismatch.
+          return 0;
+        }
+      }
+
+      // Candidate could be converted to a superclass.
+      if (isSubclassOf(candidateType, paramType))
+        return 1;
+
+      // Possible Array<T> -> Unsafe*Pointer conversion.
+      if (options.contains(MatchFlag::OnParam)) {
+        if (candidateType->isArray() &&
+            paramType->getAnyPointerElementType())
+          return 1;
+      }
+
+      // If both argument and parameter are tuples of the same arity,
+      // it's a match.
+      {
+        if (auto *candidateTuple = candidateType->getAs<TupleType>()) {
+          auto *paramTuple = paramType->getAs<TupleType>();
+          if (paramTuple &&
+              candidateTuple->getNumElements() == paramTuple->getNumElements())
+            return 1;
+        }
+      }
+
+      // If the parameter is `Any` we assume that all candidates are
+      // convertible to it, which makes it a perfect match. The solver
+      // would then decide whether erasing to an existential is preferable.
+      if (paramType->isAny())
+        return 1;
+
+      // Check if a candidate could be matched to a parameter by
+      // an existential opening.
+      if (options.contains(MatchFlag::OnParam) &&
+          candidateType->getMetatypeInstanceType()->isExistentialType()) {
+        if (auto *genericParam = paramType->getMetatypeInstanceType()
+                                     ->getAs<GenericTypeParamType>()) {
+          if (canOpenExistentialAt(choice, *paramIdx, genericParam,
+                                   candidateType->getMetatypeInstanceType())) {
+            // Lower the score slightly for operators to make sure that
+            // concrete overloads are always preferred over generic ones.
+            return choice->isOperator() ? 0.9 : 1;
+          }
+        }
+      }
+
+      // Check protocol requirement(s) if this parameter is a
+      // generic parameter type.
+      if (genericSig && paramType->isTypeParameter()) {
+        // Light-weight check if cases where `checkRequirements` is not
+        // applicable.
+        auto checkProtocolRequirementsOnly = [&]() -> double {
+          auto protocolRequirements =
+              genericSig->getRequiredProtocols(paramType);
+          if (llvm::all_of(protocolRequirements, [&](ProtocolDecl *protocol) {
+                return bool(cs.lookupConformance(candidateType, protocol));
+              })) {
+            if (auto *GP = paramType->getAs<GenericTypeParamType>()) {
+              auto *paramDecl = GP->getDecl();
+              if (paramDecl && paramDecl->isOpaqueType())
+                return 1.0;
+            }
+            return 0.7;
+          }
+
+          return 0;
+        };
+
+        // If candidate is not fully resolved or is matched against a
+        // dependent member type (i.e. `Self.T`), let's check conformances
+        // only and lower the score.
+        if (candidateType->hasTypeVariable() ||
+            candidateType->hasUnboundGenericType() ||
+            paramType->is<DependentMemberType>()) {
+          return checkProtocolRequirementsOnly();
+        }
+
+        // Cannot match anything but generic type parameters here.
+        if (!paramType->is<GenericTypeParamType>())
+          return std::nullopt;
+
+        bool hasUnsatisfiableRequirements = false;
+        SmallVector<Requirement, 4> requirements;
+
+        for (const auto &requirement : genericSig.getRequirements()) {
+          if (hasUnsatisfiableRequirements)
+            break;
+
+          llvm::SmallPtrSet<GenericTypeParamType *, 2> toExamine;
+
+          auto recordReferencesGenericParams = [&toExamine](Type type) {
+            type.visit([&toExamine](Type innerTy) {
+              if (auto *GP = innerTy->getAs<GenericTypeParamType>())
+                toExamine.insert(GP);
+            });
+          };
+
+          recordReferencesGenericParams(requirement.getFirstType());
+
+          if (requirement.getKind() != RequirementKind::Layout)
+            recordReferencesGenericParams(requirement.getSecondType());
+
+          if (llvm::any_of(toExamine, [&](GenericTypeParamType *GP) {
+                return paramType->isEqual(GP);
+              })) {
+            requirements.push_back(requirement);
+            // If requirement mentions other generic parameters
+            // `checkRequirements` would because we don't have
+            // candidate substitutions for anything but the current
+            // parameter type.
+            hasUnsatisfiableRequirements |= toExamine.size() > 1;
+          }
+        }
+
+        // If there are no requirements associated with the generic
+        // parameter or dependent member type it could match any type.
+        if (requirements.empty())
+          return 0.7;
+
+        // If some of the requirements cannot be satisfied, because
+        // they reference other generic parameters, for example:
+        // `<T, U, where T.Element == U.Element>`, let's perform a
+        // light-weight check instead of skipping this overload choice.
+        if (hasUnsatisfiableRequirements)
+          return checkProtocolRequirementsOnly();
+
+        // If the candidate type is fully resolved, let's check all of
+        // the requirements that are associated with the corresponding
+        // parameter, if all of them are satisfied this candidate is
+        // an exact match.
+        auto result = checkRequirements(
+            requirements,
+            [&paramType, &candidateType](SubstitutableType *type) -> Type {
+              if (type->isEqual(paramType))
+                return candidateType;
+              return ErrorType::get(type);
+            },
+            SubstOptions(std::nullopt));
+
+        // Concrete operator overloads are always more preferable to
+        // generic ones if there are exact or subtype matches, for
+        // everything else the solver should try both concrete and
+        // generic and disambiguate during ranking.
+        if (result == CheckRequirementsResult::Success)
+          return choice->isOperator() ? 0.9 : 1.0;
+
+        return 0;
+      }
+
+      // Parameter is generic, let's check whether top-level
+      // types match i.e. Array<Element> as a parameter.
+      //
+      // This is slightly better than all of the conformances matching
+      // because the parameter is concrete and could split the system.
+      if (paramType->hasTypeParameter()) {
+        auto *candidateDecl = candidateType->getAnyNominal();
+        auto *paramDecl = paramType->getAnyNominal();
+
+        // Conservatively we need to make sure that this is not worse
+        // than matching against a generic parameter with or without
+        // requirements.
+        if (candidateDecl && paramDecl && candidateDecl == paramDecl) {
+          // If the candidate it not yet fully resolved, let's lower the
+          // score slightly to avoid over-favoring generic overload choices.
+          if (candidateType->hasTypeVariable())
+            return 0.8;
+
+          // If the candidate is fully resolved we need to treat this
+          // as we would generic parameter otherwise there is a risk
+          // of skipping some of the valid choices.
+          return choice->isOperator() ? 0.9 : 1.0;
+        }
+      }
+
+      return 0;
+    };
+
+    // The choice with the best score.
+    double bestScore = 0.0;
+    SmallVector<std::pair<Constraint *, double>, 2> favoredChoices;
+
+    forEachDisjunctionChoice(
+        cs, disjunction,
+        [&](Constraint *choice, ValueDecl *decl, FunctionType *overloadType) {
+          GenericSignature genericSig;
+          {
+            if (auto *GF = dyn_cast<AbstractFunctionDecl>(decl)) {
+              genericSig = GF->getGenericSignature();
+            } else if (auto *SD = dyn_cast<SubscriptDecl>(decl)) {
+              genericSig = SD->getGenericSignature();
+            }
+          }
+
+          auto matchings =
+              matchArguments(choice->getOverloadChoice(), overloadType);
+          if (!matchings)
+            return;
+
+          // Require exact matches only if all of the arguments
+          // are literals and there are no usable contextual result
+          // types that could help narrow favored choices.
+          bool favorExactMatchesOnly =
+              onlySpeculativeArgumentCandidates &&
+              (!canUseContextualResultTypes || resultTypes.empty());
+
+          // This is important for SIMD operators in particular because
+          // a lot of their overloads have same-type requires to a concrete
+          // type:  `<Scalar == (U)Int*>(_: SIMD*<Scalar>, ...) -> ...`.
+          if (genericSig) {
+            overloadType = overloadType->getReducedType(genericSig)
+                               ->castTo<FunctionType>();
+          }
+
+          double score = 0.0;
+          unsigned numDefaulted = 0;
+          for (unsigned paramIdx = 0, n = overloadType->getNumParams();
+               paramIdx != n; ++paramIdx) {
+            const auto &param = overloadType->getParams()[paramIdx];
+
+            auto argIndices = matchings->parameterBindings[paramIdx];
+            switch (argIndices.size()) {
+            case 0:
+              // Current parameter is defaulted, mark and continue.
+              ++numDefaulted;
+              continue;
+
+            case 1:
+              // One-to-one match between argument and parameter.
+              break;
+
+            default:
+              // Cannot deal with multiple possible matchings at the moment.
+              return;
+            }
+
+            auto argIdx = argIndices.front();
+
+            // Looks like there is nothing know about the argument.
+            if (argumentCandidates[argIdx].empty())
+              continue;
+
+            const auto paramFlags = param.getParameterFlags();
+
+            // If parameter is variadic we cannot compare because we don't know
+            // real arity.
+            if (paramFlags.isVariadic())
+              continue;
+
+            auto paramType = param.getPlainType();
+
+            if (paramFlags.isAutoClosure())
+              paramType = paramType->castTo<AnyFunctionType>()->getResult();
+
+            // FIXME: Let's skip matching function types for now
+            // because they have special rules for e.g. Concurrency
+            // (around @Sendable) and @convention(c).
+            if (paramType->lookThroughAllOptionalTypes()->is<FunctionType>())
+              continue;
+
+            // The idea here is to match the parameter type against
+            // all of the argument candidate types and pick the best
+            // match (i.e. exact equality one).
+            //
+            // If none of the candidates match exactly and they are
+            // all bound concrete types, we consider this is mismatch
+            // at this parameter position and remove the overload choice
+            // from consideration.
+            double bestCandidateScore = 0;
+            llvm::BitVector mismatches(argumentCandidates[argIdx].size());
+
+            for (unsigned candidateIdx :
+                 indices(argumentCandidates[argIdx])) {
+              // If one of the candidates matched exactly there is no reason
+              // to continue checking.
+              if (bestCandidateScore == 1)
+                break;
+
+              auto candidate = argumentCandidates[argIdx][candidateIdx];
+
+              // `inout` parameter accepts only l-value argument.
+              if (paramFlags.isInOut() && !candidate.type->is<LValueType>()) {
+                mismatches.set(candidateIdx);
+                continue;
+              }
+
+              MatchOptions options(MatchFlag::OnParam);
+              if (candidate.fromLiteral)
+                options |= MatchFlag::Literal;
+              if (favorExactMatchesOnly)
+                options |= MatchFlag::ExactOnly;
+
+              // Disable CGFloat -> Double conversion for unary operators.
+              //
+              // Some of the unary operators, i.e. prefix `-`, don't have
+              // CGFloat variants and expect generic `FloatingPoint` overload
+              // to match CGFloat type. Let's not attempt `CGFloat` -> `Double`
+              // conversion for unary operators because it always leads
+              // to a worse solutions vs. generic overloads.
+              if (n == 1 && decl->isOperator())
+                options |= MatchFlag::DisableCGFloatDoubleConversion;
+
+              // Disable implicit CGFloat -> Double widening conversion if
+              // argument is an explicit call to `CGFloat` initializer.
+              if (candidate.type->isCGFloat() &&
+                  candidate.fromInitializerCall)
+                options |= MatchFlag::DisableCGFloatDoubleConversion;
+
+              if (isExpr<InterpolatedStringLiteralExpr>(
+                      argumentList->getExpr(argIdx)
+                          ->getSemanticsProvidingExpr()))
+                options |= MatchFlag::StringInterpolation;
+
+              // The specifier for a candidate only matters for `inout` check.
+              auto candidateScore =
+                  scoreCandidateMatch(genericSig, decl, paramIdx,
+                                      candidate.type->getWithoutSpecifierType(),
+                                      paramType, options);
+
+              if (!candidateScore)
+                continue;
+
+              if (candidateScore > 0) {
+                bestCandidateScore =
+                    std::max(bestCandidateScore, candidateScore.value());
+                continue;
+              }
+
+              if (!candidate.type->hasTypeVariable())
+                mismatches.set(candidateIdx);
+            }
+
+            // If none of the candidates for this parameter matched, let's
+            // drop this overload from any further consideration.
+            if (mismatches.all())
+              return;
+
+            score += bestCandidateScore;
+          }
+
+          // An overload whether all of the parameters are defaulted
+          // that's called without arguments.
+          if (numDefaulted == overloadType->getNumParams())
+            return;
+
+          // Average the score to avoid disfavoring disjunctions with fewer
+          // parameters.
+          score /= (overloadType->getNumParams() - numDefaulted);
+
+          // If one of the result types matches exactly, that's a good
+          // indication that overload choice should be favored.
+          //
+          // It's only safe to match result types of operators
+          // because regular functions/methods/subscripts and
+          // especially initializers could end up with a lot of
+          // favored overloads because on the result type alone.
+          if (canUseContextualResultTypes &&
+              (score > 0 || !hasArgumentCandidates)) {
+            if (llvm::any_of(resultTypes, [&](const Type candidateResultTy) {
+                  return scoreCandidateMatch(genericSig, decl,
+                                             /*paramIdx=*/std::nullopt,
+                                             overloadType->getResult(),
+                                             candidateResultTy,
+                                             /*options=*/{}) > 0;
+                })) {
+              score += 1.0;
+            }
+          }
+
+          if (score > 0) {
+            // Nudge the score slightly to prefer concrete homogeneous
+						// arithmetic operators.
+            //
+            // This is an opportunistic optimization based on the operator
+            // use patterns where homogeneous operators are the most
+            // heavily used ones.
+            if (isArithmeticOperator(decl) &&
+                overloadType->getNumParams() == 2) {
+              auto resultTy = overloadType->getResult();
+              if (!resultTy->hasTypeParameter() &&
+                  llvm::all_of(overloadType->getParams(),
+                               [&resultTy](const auto &param) {
+                                 return param.getPlainType()->isEqual(resultTy);
+                               }))
+                score += 0.01;
+            }
+
+            favoredChoices.push_back({choice, score});
+            bestScore = std::max(bestScore, score);
+          }
+        });
+
+    if (cs.isDebugMode()) {
+
+      llvm::errs().indent(cs.solverState->getCurrentIndent())
+          << "<<< Disjunction "
+          << disjunction->getNestedConstraints()[0]->getFirstType()->getString(
+                 PrintOptions::forDebugging())
+          << " with score " << bestScore << "\n";
+    }
+
+    bestOverallScore = std::max(bestOverallScore, bestScore);
+
+    // Determine if the score and favoring decisions here are
+    // based only on "speculative" sources i.e. inference from
+    // literals.
+    //
+    // This information is going to be used by the disjunction
+    // selection algorithm to prevent over-eager selection of
+    // the operators over unsupported non-operator declarations.
+    bool isSpeculative = onlySpeculativeArgumentCandidates &&
+                         (!canUseContextualResultTypes ||
+                          !anyNonSpeculativeResultTypes(resultTypes));
+
+    DisjunctionInfoBuilder info(/*score=*/bestScore);
+
+    info.setSpeculative(isSpeculative);
+
+    for (const auto &choice : favoredChoices) {
+      if (choice.second == bestScore)
+        info.addFavoredChoice(choice.first);
+    }
+
+    recordResult(disjunction, info.build());
+  }
+
+  if (cs.isDebugMode() && bestOverallScore > 0) {
+    PrintOptions PO = PrintOptions::forDebugging();
+
+    auto getLogger = [&](unsigned extraIndent = 0) -> llvm::raw_ostream & {
+      return llvm::errs().indent(cs.solverState->getCurrentIndent() +
+                                 extraIndent);
+    };
+
+    {
+      auto &log = getLogger();
+      log << "(Optimizing disjunctions: [";
+
+      interleave(
+          disjunctions,
+          [&](const auto *disjunction) {
+            log << disjunction->getNestedConstraints()[0]
+                       ->getFirstType()
+                       ->getString(PO);
+          },
+          [&]() { log << ", "; });
+
+      log << "]\n";
+    }
+
+    getLogger(/*extraIndent=*/4)
+        << "Best overall score = " << bestOverallScore << '\n';
+
+    for (auto *disjunction : disjunctions) {
+      auto &entry = result[disjunction];
+      getLogger(/*extraIndent=*/4)
+          << "[Disjunction '"
+          << disjunction->getNestedConstraints()[0]->getFirstType()->getString(
+                 PO)
+          << "' with score = " << entry.Score.value_or(0) << '\n';
+
+      for (const auto *choice : entry.FavoredChoices) {
+        auto &log = getLogger(/*extraIndent=*/6);
+
+        log << "- ";
+        choice->print(log, &cs.getASTContext().SourceMgr);
+        log << '\n';
+      }
+
+      getLogger(/*extraIdent=*/4) << "]\n";
+    }
+
+    getLogger() << ")\n";
+  }
+}
+
+static std::optional<bool> isPreferable(ConstraintSystem &cs,
+                                        Constraint *disjunctionA,
+                                        Constraint *disjunctionB) {
+  // Consider only operator vs. non-operator situations.
+  if (isOperatorDisjunction(disjunctionA) ==
+      isOperatorDisjunction(disjunctionB))
+    return std::nullopt;
+
+  // Prevent operator selection if its passed as an argument
+  // to not-yet resolved call. This helps to make sure that
+  // in result builder context chained members and other
+  // non-operator disjunctions are always selected first,
+  // because they provide the context and help to prune the system.
+  if (isInResultBuilderContext(cs, disjunctionA)) {
+    if (isOperatorDisjunction(disjunctionA)) {
+      if (isOperatorPassedToUnresolvedCall(cs, disjunctionA))
+        return false;
+    } else {
+      if (isOperatorPassedToUnresolvedCall(cs, disjunctionB))
+        return true;
+    }
+  }
+
+  return std::nullopt;
+}
+
+std::optional<std::pair<Constraint *, llvm::TinyPtrVector<Constraint *>>>
+ConstraintSystem::selectDisjunction() {
+  if (performanceHacksEnabled()) {
+    if (auto *disjunction = selectDisjunctionWithHacks())
+      return std::make_pair(disjunction, llvm::TinyPtrVector<Constraint *>());
+    return std::nullopt;
+  }
+
+  SmallVector<Constraint *, 4> disjunctions;
+
+  collectDisjunctions(disjunctions);
+  if (disjunctions.empty())
+    return std::nullopt;
+
+  llvm::DenseMap<Constraint *, DisjunctionInfo> favorings;
+  determineBestChoicesInContext(*this, disjunctions, favorings);
+
+  // Pick the disjunction with the smallest number of favored, then active
+  // choices.
+  auto bestDisjunction = std::min_element(
+      disjunctions.begin(), disjunctions.end(),
+      [&](Constraint *first, Constraint *second) -> bool {
+        unsigned firstActive = first->countActiveNestedConstraints();
+        unsigned secondActive = second->countActiveNestedConstraints();
+
+        if (firstActive == 1 || secondActive == 1)
+          return secondActive != 1;
+
+        if (auto preference = isPreferable(*this, first, second))
+          return preference.value();
+
+        auto &[firstScore, firstFavoredChoices, isFirstSpeculative] =
+            favorings[first];
+        auto &[secondScore, secondFavoredChoices, isSecondSpeculative] =
+            favorings[second];
+
+        bool isFirstOperator = isOperatorDisjunction(first);
+        bool isSecondOperator = isOperatorDisjunction(second);
+
+        // Infix logical operators are usually not overloaded and don't
+        // form disjunctions, but when they do, let's prefer them over
+        // other operators when they have fewer choices because it helps
+        // to split operator chains.
+        if (isFirstOperator && isSecondOperator) {
+          if (isStandardInfixLogicalOperator(first) !=
+              isStandardInfixLogicalOperator(second))
+            return firstActive < secondActive;
+        }
+
+        // Not all of the non-operator disjunctions are supported by the
+        // ranking algorithm, so to prevent eager selection of operators
+        // when nothing concrete is known about them, let's reset the score
+        // and compare purely based on number of choices.
+        if (isFirstOperator != isSecondOperator) {
+          if (isFirstOperator && isFirstSpeculative)
+            firstScore = 0;
+
+          if (isSecondOperator && isSecondSpeculative)
+            secondScore = 0;
+        }
+
+        // Rank based on scores only if both disjunctions are supported.
+        if (firstScore && secondScore) {
+          // If both disjunctions have the same score they should be ranked
+          // based on number of favored/active choices.
+          if (*firstScore != *secondScore)
+            return *firstScore > *secondScore;
+
+          // If the scores are the same and both disjunctions are operators
+          // they could be ranked purely based on whether the candidates
+          // were speculative or not. The one with more context always wins.
+          //
+          // Consider the following situation:
+          //
+          // func test(_: Int) { ... }
+          // func test(_: String) { ... }
+          //
+          // test("a" + "b" + "c")
+          //
+          // In this case we should always prefer ... + "c" over "a" + "b"
+          // because it would fail and prune the other overload if parameter
+          // type (aka contextual type) is `Int`.
+          if (isFirstOperator && isSecondOperator &&
+              isFirstSpeculative != isSecondSpeculative)
+            return isSecondSpeculative;
+        }
+
+        // Use favored choices only if disjunction score is higher
+        // than zero. This means that we can maintain favoring
+        // choices without impacting selection decisions.
+        unsigned numFirstFavored =
+            firstScore.value_or(0) ? firstFavoredChoices.size() : 0;
+        unsigned numSecondFavored =
+            secondScore.value_or(0) ? secondFavoredChoices.size() : 0;
+
+        if (numFirstFavored == numSecondFavored) {
+          if (firstActive != secondActive)
+            return firstActive < secondActive;
+        }
+
+        numFirstFavored = numFirstFavored ? numFirstFavored : firstActive;
+        numSecondFavored = numSecondFavored ? numSecondFavored : secondActive;
+
+        return numFirstFavored < numSecondFavored;
+      });
+
+  if (bestDisjunction != disjunctions.end())
+    return std::make_pair(*bestDisjunction,
+                          favorings[*bestDisjunction].FavoredChoices);
+
+  return std::nullopt;
+}
diff --git a/lib/Sema/CSRanking.cpp b/lib/Sema/CSRanking.cpp
index 81b6680b9e0dc..07bd9bc90f927 100644
--- a/lib/Sema/CSRanking.cpp
+++ b/lib/Sema/CSRanking.cpp
@@ -168,9 +168,6 @@ void ConstraintSystem::clearScore() {
 }
 
 bool ConstraintSystem::worseThanBestSolution() const {
-  if (getASTContext().TypeCheckerOpts.DisableConstraintSolverPerformanceHacks)
-    return false;
-
   if (!solverState || !solverState->BestScore ||
       CurrentScore <= *solverState->BestScore)
     return false;
@@ -426,7 +423,8 @@ static bool isProtocolExtensionAsSpecializedAs(DeclContext *dc1,
   // the second protocol extension.
   ConstraintSystem cs(dc1, std::nullopt);
   SmallVector<OpenedType, 4> replacements;
-  cs.openGeneric(dc2, sig2, ConstraintLocatorBuilder(nullptr), replacements);
+  cs.openGeneric(dc2, sig2, ConstraintLocatorBuilder(nullptr), replacements,
+                 /*preparedOverload=*/nullptr);
 
   // Bind the 'Self' type from the first extension to the type parameter from
   // opening 'Self' of the second extension.
@@ -467,20 +465,25 @@ static bool paramIsIUO(const ValueDecl *decl, int paramNum) {
 static bool isDeclAsSpecializedAs(DeclContext *dc, ValueDecl *decl1,
                                   ValueDecl *decl2,
                                   bool isDynamicOverloadComparison = false,
-                                  bool allowMissingConformances = true) {
+                                  bool allowMissingConformances = true,
+                                  bool debugMode = false) {
   return evaluateOrDefault(decl1->getASTContext().evaluator,
                            CompareDeclSpecializationRequest{
                                dc, decl1, decl2, isDynamicOverloadComparison,
-                               allowMissingConformances},
+                               allowMissingConformances, debugMode},
                            false);
 }
 
 bool CompareDeclSpecializationRequest::evaluate(
     Evaluator &eval, DeclContext *dc, ValueDecl *decl1, ValueDecl *decl2,
-    bool isDynamicOverloadComparison, bool allowMissingConformances) const {
+    bool isDynamicOverloadComparison, bool allowMissingConformances,
+    bool debugMode) const {
   auto &C = decl1->getASTContext();
+  ConstraintSystemOptions options;
+  if (debugMode)
+    options |= ConstraintSystemFlags::DebugConstraints;
   // Construct a constraint system to compare the two declarations.
-  ConstraintSystem cs(dc, ConstraintSystemOptions());
+  ConstraintSystem cs(dc, options);
   if (cs.isDebugMode()) {
     llvm::errs() << "Comparing declarations\n";
     decl1->print(llvm::errs());
@@ -584,13 +587,15 @@ bool CompareDeclSpecializationRequest::evaluate(
                       SmallVectorImpl<OpenedType> &replacements,
                       ConstraintLocator *locator) -> Type {
     if (auto *funcType = type->getAs<AnyFunctionType>()) {
-      return cs.openFunctionType(funcType, locator, replacements, outerDC);
+      return cs.openFunctionType(funcType, locator, replacements, outerDC,
+                                 /*preparedOverload=*/nullptr);
     }
 
     cs.openGeneric(outerDC, innerDC->getGenericSignatureOfContext(), locator,
-                   replacements);
+                   replacements, /*preparedOverload=*/nullptr);
 
-    return cs.openType(type, replacements, locator);
+    return cs.openType(type, replacements, locator,
+                       /*preparedOverload=*/nullptr);
   };
 
   bool knownNonSubtype = false;
@@ -1174,15 +1179,15 @@ SolutionCompareResult ConstraintSystem::compareSolutions(
     // Determine whether one declaration is more specialized than the other.
     bool firstAsSpecializedAs = false;
     bool secondAsSpecializedAs = false;
-    if (isDeclAsSpecializedAs(cs.DC, decl1, decl2,
-                              isDynamicOverloadComparison,
-                              /*allowMissingConformances=*/false)) {
+    if (isDeclAsSpecializedAs(cs.DC, decl1, decl2, isDynamicOverloadComparison,
+                              /*allowMissingConformances=*/false,
+                              cs.isDebugMode())) {
       score1 += weight;
       firstAsSpecializedAs = true;
     }
-    if (isDeclAsSpecializedAs(cs.DC, decl2, decl1,
-                              isDynamicOverloadComparison,
-                              /*allowMissingConformances=*/false)) {
+    if (isDeclAsSpecializedAs(cs.DC, decl2, decl1, isDynamicOverloadComparison,
+                              /*allowMissingConformances=*/false,
+                              cs.isDebugMode())) {
       score2 += weight;
       secondAsSpecializedAs = true;
     }
@@ -1413,26 +1418,10 @@ SolutionCompareResult ConstraintSystem::compareSolutions(
     auto type1 = types.Type1;
     auto type2 = types.Type2;
 
-    // If either of the types still contains type variables, we can't
-    // compare them.
-    // FIXME: This is really unfortunate. More type variable sharing
-    // (when it's sound) would help us do much better here.
-    if (type1->hasTypeVariable() || type2->hasTypeVariable()) {
-      identical = false;
-      continue;
-    }
-
-    // With introduction of holes it's currently possible to form solutions
-    // with UnresolvedType bindings, we need to account for that in
-    // ranking. If one solution has a hole for a given type variable
-    // it's always worse than any non-hole type other solution might have.
-    if (type1->is<UnresolvedType>() || type2->is<UnresolvedType>()) {
-      if (type1->is<UnresolvedType>()) {
-        ++score2;
-      } else {
-        ++score1;
-      }
-
+    // If either of the types have holes or unresolved type variables, we can't
+    // compare them. `isSubtypeOf` cannot be used with solver-allocated types.
+    if (type1->hasTypeVariableOrPlaceholder() ||
+        type2->hasTypeVariableOrPlaceholder()) {
       identical = false;
       continue;
     }
@@ -1469,15 +1458,12 @@ SolutionCompareResult ConstraintSystem::compareSolutions(
     // The systems are not considered equivalent.
     identical = false;
 
-    // Archetypes are worse than concrete types (i.e. non-placeholder and
-    // non-archetype)
+    // Archetypes are worse than concrete types
     // FIXME: Total hack.
-    if (type1->is<ArchetypeType>() && !type2->is<ArchetypeType>() &&
-        !type2->is<PlaceholderType>()) {
+    if (type1->is<ArchetypeType>() && !type2->is<ArchetypeType>()) {
       ++score2;
       continue;
-    } else if (type2->is<ArchetypeType>() && !type1->is<ArchetypeType>() &&
-               !type1->is<PlaceholderType>()) {
+    } else if (type2->is<ArchetypeType>() && !type1->is<ArchetypeType>()) {
       ++score1;
       continue;
     }
diff --git a/lib/Sema/CSSimplify.cpp b/lib/Sema/CSSimplify.cpp
index a1b6cc8a68bbb..ff5bcb9ccd6e3 100644
--- a/lib/Sema/CSSimplify.cpp
+++ b/lib/Sema/CSSimplify.cpp
@@ -40,6 +40,7 @@
 #include "swift/Sema/CSFix.h"
 #include "swift/Sema/ConstraintSystem.h"
 #include "swift/Sema/IDETypeChecking.h"
+#include "swift/Sema/PreparedOverload.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/Support/Compiler.h"
 
@@ -279,10 +280,9 @@ static ConstraintSystem::TypeMatchOptions getDefaultDecompositionOptions(
 }
 
 /// Whether the given parameter requires an argument.
-bool swift::parameterRequiresArgument(
-    ArrayRef<AnyFunctionType::Param> params,
-    const ParameterListInfo &paramInfo,
-    unsigned paramIdx) {
+static bool parameterRequiresArgument(ArrayRef<AnyFunctionType::Param> params,
+                                      const ParameterListInfo &paramInfo,
+                                      unsigned paramIdx) {
   return !paramInfo.hasDefaultArgument(paramIdx)
       && !params[paramIdx].isVariadic();
 }
@@ -300,7 +300,6 @@ static bool backwardScanAcceptsTrailingClosure(
       paramTy->is<ArchetypeType>() ||
       paramTy->is<AnyFunctionType>() ||
       paramTy->isTypeVariableOrMember() ||
-      paramTy->is<UnresolvedType>() ||
       paramTy->isAny();
 }
 
@@ -374,8 +373,15 @@ static bool matchCallArgumentsImpl(
   auto claim = [&](Identifier expectedName, unsigned argIdx,
                    bool ignoreNameClash = false)  -> unsigned {
     // Make sure we can claim this argument.
-    assert(argIdx != numArgs && "Must have a valid index to claim");
-    assert(!claimedArgs[argIdx] && "Argument already claimed");
+    ASSERT(argIdx != numArgs && "Must have a valid index to claim");
+    ASSERT(!claimedArgs[argIdx] && "Argument already claimed");
+
+    // Prevent recording of an argument label mismatche for an unlabeled
+    // trailing closure. An unlabeled trailing closure is necessarily the first
+    // one and vice versa, per language syntax.
+    if (unlabeledTrailingClosureArgIndex == argIdx) {
+      expectedName = Identifier();
+    }
 
     if (!actualArgNames.empty()) {
       // We're recording argument names; record this one.
@@ -2968,7 +2974,7 @@ ConstraintSystem::matchFunctionIsolations(FunctionType *func1,
       return true;
 
     // A thunk is going to pass `nil` to the isolated parameter.
-    case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+    case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
       return matchIfConversion();
 
     // Erasing global-actor isolation to non-isolation can admit data
@@ -2992,10 +2998,10 @@ ConstraintSystem::matchFunctionIsolations(FunctionType *func1,
     llvm_unreachable("bad kind");
 
   // Converting to a caller isolated async function type.
-  case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+  case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
     switch (isolation1.getKind()) {
     // Exact match.
-    case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+    case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
       return true;
 
     // Global actor: Thunk will hop to the global actor
@@ -3042,7 +3048,7 @@ ConstraintSystem::matchFunctionIsolations(FunctionType *func1,
 
     // A thunk is going to pass in an instance of a global actor
     // to the isolated parameter.
-    case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+    case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
       return matchIfConversion();
 
     // Parameter isolation cannot be altered in the same way.
@@ -3072,7 +3078,7 @@ ConstraintSystem::matchFunctionIsolations(FunctionType *func1,
       return matchIfConversion();
 
     // A thunk is going to forward the isolation.
-    case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+    case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
       return matchIfConversion();
 
     // Don't allow dynamically-isolated function types to convert to
@@ -3097,7 +3103,7 @@ ConstraintSystem::matchFunctionIsolations(FunctionType *func1,
 
     // It's not possible to form a thunk for this case because
     // we don't know what to pass to the isolated parameter.
-    case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+    case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
       return false;
 
     // Parameter isolation is value-dependent and can't be erased in the
@@ -3303,14 +3309,14 @@ ConstraintSystem::matchFunctionTypes(FunctionType *func1, FunctionType *func2,
   SmallVector<AnyFunctionType::Param, 8> func2Params;
   func2Params.append(func2->getParams().begin(), func2->getParams().end());
 
-  // Support conversion from `@execution(caller)` to a function type
+  // Support conversion from `nonisolated(nonsending)` to a function type
   // with an isolated parameter.
   if (subKind == ConstraintKind::Subtype &&
       func1->getIsolation().isNonIsolatedCaller() &&
       func2->getIsolation().isParameter()) {
-    // `@execution(caller)` function gets an implicit isolation parameter
-    // introduced during SILGen and thunk is going to forward an isolation
-    // from the caller to it.
+    // `nonisolated(nonsending)` function gets an implicit isolation parameter
+    // introduced during SILGen and thunk is going to forward an isolation from
+    // the caller to it.
     // Let's remove the isolated parameter from consideration, function
     // types have to match on everything else.
     llvm::erase_if(func2Params, [](const AnyFunctionType::Param &param) {
@@ -4039,6 +4045,12 @@ ConstraintSystem::matchDeepEqualityTypes(Type type1, Type type2,
       getConstraintLocator(locator, {LocatorPathElt::GenericType(type1),
           LocatorPathElt::GenericType(type2)});
 
+    // Optionals have a lot of special diagnostics and only one
+    // generic argument so if we're dealing with one, let's allow
+    // `repairFailures` to take care of it.
+    if (bound1->getDecl()->isOptionalDecl())
+      return matchDeepTypeArguments(*this, subflags, args1, args2, baseLoc);
+
     auto argMatchingFlags = subflags;
     // Allow the solver to produce separate fixes while matching
     // key path's root/value to a contextual type instead of the
@@ -4049,13 +4061,6 @@ ConstraintSystem::matchDeepEqualityTypes(Type type1, Type type2,
       argMatchingFlags |= TMF_MatchingGenericArguments;
     }
 
-    // Optionals have a lot of special diagnostics and only one
-    // generic argument so if we' re dealing with one, don't produce generic
-    // arguments mismatch fixes.
-    if (bound1->getDecl()->isOptionalDecl())
-      return matchDeepTypeArguments(*this, argMatchingFlags, args1, args2,
-                                    baseLoc);
-
     SmallVector<unsigned, 4> mismatches;
     auto result = matchDeepTypeArguments(
         *this, argMatchingFlags, args1, args2, baseLoc,
@@ -4282,7 +4287,8 @@ ConstraintSystem::matchExistentialTypes(Type type1, Type type2,
         if (!path.empty()) {
           auto last = path.back();
 
-          if (last.is<LocatorPathElt::ApplyArgToParam>()) {
+          if (last.is<LocatorPathElt::ApplyArgToParam>() ||
+              last.is<LocatorPathElt::AutoclosureResult>()) {
             auto proto = protoDecl->getDeclaredInterfaceType();
             // Impact is 2 here because there are two failures
             // 1 - missing conformance and 2 - incorrect argument type.
@@ -4310,6 +4316,15 @@ ConstraintSystem::matchExistentialTypes(Type type1, Type type2,
             break;
           }
 
+          if ((isExpr<ArrayExpr>(anchor) || isExpr<DictionaryExpr>(anchor)) &&
+              last.is<LocatorPathElt::TupleElement>()) {
+            auto *fix = CollectionElementContextualMismatch::create(
+                *this, type1, type2, getConstraintLocator(anchor, path));
+            if (recordFix(fix, /*impact=*/2))
+              return getTypeMatchFailure(locator);
+            break;
+          }
+
           // TODO(diagnostics): If there are any requirement failures associated
           // with result types which are part of a function type conversion,
           // let's record general conversion mismatch in order for it to capture
@@ -4894,8 +4909,12 @@ static bool
 repairViaBridgingCast(ConstraintSystem &cs, Type fromType, Type toType,
                       SmallVectorImpl<RestrictionOrFix> &conversionsOrFixes,
                       ConstraintLocatorBuilder locator) {
-  if (fromType->hasTypeVariable() || toType->hasTypeVariable())
+  // Don't check if any of the types have type variables or placeholders,
+  // `typeCheckCheckedCast` doesn't support checking solver-allocated types.
+  if (fromType->hasTypeVariableOrPlaceholder() ||
+      toType->hasTypeVariableOrPlaceholder()) {
     return false;
+  }
 
   auto objectType1 = fromType->getOptionalObjectType();
   auto objectType2 = toType->getOptionalObjectType();
@@ -4979,8 +4998,18 @@ repairViaOptionalUnwrap(ConstraintSystem &cs, Type fromType, Type toType,
 
     // First, let's check whether it has been determined that
     // it was incorrect to use `?` in this position.
-    if (cs.hasFixFor(cs.getConstraintLocator(subExpr), FixKind::RemoveUnwrap))
+    if (cs.hasFixFor(cs.getConstraintLocator(subExpr), FixKind::RemoveUnwrap)) {
+      if (auto *typeVar =
+              fromType->getOptionalObjectType()->getAs<TypeVariableType>()) {
+        // If the optional chain is invalid let's unwrap optional and
+        // re-introduce the constraint to be solved later once both sides
+        // are sufficiently resolved, this would allow to diagnose not only
+        // the invalid unwrap but an invalid conversion (if any) as well.
+        cs.addConstraint(matchKind, typeVar, toType,
+                         cs.getConstraintLocator(locator));
+      }
       return true;
+    }
 
     auto type = cs.getType(subExpr);
     // If the type of sub-expression is optional, type of the
@@ -5336,6 +5365,11 @@ bool ConstraintSystem::repairFailures(
       matchKind = ConstraintKind::Conversion;
     }
 
+    // FIXME: There is currently no easy way to avoid attempting
+    // fixes, matchTypes do not propagate `TMF_ApplyingFix` flag.
+    llvm::SaveAndRestore<ConstraintSystemOptions> options(
+        Options, Options - ConstraintSystemFlags::AllowFixes);
+
     auto result = matchTypes(resultType, dstType, matchKind,
                              TypeMatchFlags::TMF_ApplyingFix, locator);
 
@@ -5534,6 +5568,17 @@ bool ConstraintSystem::repairFailures(
     return true;
   };
 
+  // Propagate a hole from one type to another. This is useful for contextual
+  // types since type resolution forms a top-level ErrorType for types with
+  // nested errors, e.g `S<@error_type>` becomes `@error_type`. As such, when
+  // matching `S<$T0> == $T1` where `$T1` is a hole from a contextual type, we
+  // want to eagerly turn `$T0` into a hole since it's likely that `$T1` would
+  // have provided the contextual info for it.
+  auto tryPropagateHole = [&](Type from, Type to) {
+    if (from->isPlaceholder() && to->hasTypeVariable())
+      recordTypeVariablesAsHoles(to);
+  };
+
   if (path.empty()) {
     if (!anchor)
       return false;
@@ -5552,7 +5597,7 @@ bool ConstraintSystem::repairFailures(
     // fix-up here unless last component has already a invalid type or
     // instance fix recorded.
     if (isExpr<KeyPathExpr>(anchor)) {
-      if (isKnownKeyPathType(lhs) && isKnownKeyPathType(rhs)) {
+      if (lhs->isKnownKeyPathType() && rhs->isKnownKeyPathType()) {
         // If we have a conversion happening here, we should let fix happen in
         // simplifyRestrictedConstraint.
         if (hasAnyRestriction())
@@ -5775,6 +5820,41 @@ bool ConstraintSystem::repairFailures(
         break;
       }
 
+      // There is no subtyping between object types of inout argument/parameter.
+      if (auto argConv = path.back().getAs<LocatorPathElt::ApplyArgToParam>()) {
+        // Attempt conversions first.
+        if (hasAnyRestriction())
+          break;
+
+        // Unwraps are allowed to preserve l-valueness so we can suggest
+        // them here.
+        if (repairViaOptionalUnwrap(*this, lhs, rhs, matchKind,
+                                    conversionsOrFixes, locator))
+          return true;
+
+        auto *loc = getConstraintLocator(locator);
+
+        auto result = matchTypes(lhs, rhs, ConstraintKind::Conversion,
+                                 TMF_ApplyingFix, locator);
+
+        ConstraintFix *fix = nullptr;
+        if (result.isFailure()) {
+          // If this is a "destination" argument to a mutating operator
+          // like `+=`, let's consider it contextual and only attempt
+          // to fix type mismatch on the "source" right-hand side of
+          // such operators.
+          if (isOperatorArgument(loc) && argConv->getArgIdx() == 0)
+            break;
+
+          fix = AllowArgumentMismatch::create(*this, lhs, rhs, loc);
+        } else {
+          fix = AllowInOutConversion::create(*this, lhs, rhs, loc);
+        }
+
+        conversionsOrFixes.push_back(fix);
+        break;
+      }
+
       // If this is a problem with result type of a subscript setter,
       // let's re-attempt to repair without l-value conversion in the
       // locator to fix underlying type mismatch.
@@ -5794,7 +5874,7 @@ bool ConstraintSystem::repairFailures(
         break;
     }
 
-    LLVM_FALLTHROUGH;
+    break;
   }
 
   case ConstraintLocator::ApplyArgToParam: {
@@ -5874,52 +5954,6 @@ bool ConstraintSystem::repairFailures(
     if (repairByTreatingRValueAsLValue(lhs, rhs))
       break;
 
-    // If the problem is related to missing unwrap, there is a special
-    // fix for that.
-    if (lhs->getOptionalObjectType() && !rhs->getOptionalObjectType()) {
-      // If this is an attempt to check whether optional conforms to a
-      // particular protocol, let's do that before attempting to force
-      // unwrap the optional.
-      if (hasConversionOrRestriction(ConversionRestrictionKind::Existential))
-        break;
-
-      auto result = matchTypes(lhs->getOptionalObjectType(), rhs, matchKind,
-                               TMF_ApplyingFix, locator);
-
-      if (result.isSuccess()) {
-        conversionsOrFixes.push_back(
-            ForceOptional::create(*this, lhs, rhs, loc));
-        break;
-      }
-    }
-
-    // There is no subtyping between object types of inout argument/parameter.
-    if (elt.getKind() == ConstraintLocator::LValueConversion) {
-      auto result = matchTypes(lhs, rhs, ConstraintKind::Conversion,
-                               TMF_ApplyingFix, locator);
-
-      ConstraintFix *fix = nullptr;
-      if (result.isFailure()) {
-        // If this is a "destination" argument to a mutating operator
-        // like `+=`, let's consider it contextual and only attempt
-        // to fix type mismatch on the "source" right-hand side of
-        // such operators.
-        if (isOperatorArgument(loc) &&
-            loc->findLast<LocatorPathElt::ApplyArgToParam>()->getArgIdx() == 0)
-          break;
-
-        fix = AllowArgumentMismatch::create(*this, lhs, rhs, loc);
-      } else {
-        fix = AllowInOutConversion::create(*this, lhs, rhs, loc);
-      }
-
-      conversionsOrFixes.push_back(fix);
-      break;
-    }
-
-    if (elt.getKind() != ConstraintLocator::ApplyArgToParam)
-      break;
-
     // If argument in l-value type and parameter is `inout` or a pointer,
     // let's see if it's generic parameter matches and suggest adding explicit
     // `&`.
@@ -6018,7 +6052,7 @@ bool ConstraintSystem::repairFailures(
     // ```
     if (rhs->isKnownStdlibCollectionType()) {
       std::function<Type(Type)> getArrayOrSetType = [&](Type type) -> Type {
-        if (auto eltTy = type->isArrayType())
+        if (auto eltTy = type->getArrayElementType())
           return getArrayOrSetType(eltTy);
 
         if (auto eltTy = isSetType(type))
@@ -6046,7 +6080,7 @@ bool ConstraintSystem::repairFailures(
 
     if (repairViaOptionalUnwrap(*this, lhs, rhs, matchKind, conversionsOrFixes,
                                 locator))
-      break;
+      return true;
 
     {
       auto *calleeLocator = getCalleeLocator(loc);
@@ -6318,6 +6352,13 @@ bool ConstraintSystem::repairFailures(
 
   case ConstraintLocator::ClosureBody:
   case ConstraintLocator::ClosureResult: {
+    // If either type is a placeholder, consider this fixed, eagerly propagating
+    // a hole from the contextual type.
+    if (lhs->isPlaceholder() || rhs->isPlaceholder()) {
+      tryPropagateHole(rhs, lhs);
+      return true;
+    }
+
     if (repairByInsertingExplicitCall(lhs, rhs))
       break;
 
@@ -6337,9 +6378,12 @@ bool ConstraintSystem::repairFailures(
   }
 
   case ConstraintLocator::ContextualType: {
-    // If either type is a placeholder, consider this fixed
-    if (lhs->isPlaceholder() || rhs->isPlaceholder())
+    // If either type is a placeholder, consider this fixed, eagerly propagating
+    // a hole from the contextual type.
+    if (lhs->isPlaceholder() || rhs->isPlaceholder()) {
+      tryPropagateHole(rhs, lhs);
       return true;
+    }
 
     // If either side is not yet resolved, it's too early for this fix.
     if (lhs->isTypeVariableOrMember() || rhs->isTypeVariableOrMember())
@@ -6638,12 +6682,6 @@ bool ConstraintSystem::repairFailures(
     if (rhs->isExistentialType())
       break;
 
-    // If the types didn't line up, let's allow right-hand side
-    // of the conversion (or pattern match) to have holes. This
-    // helps when conversion if between a type and a tuple e.g.
-    // `Int` vs. `(_, _)`.
-    recordAnyTypeVarAsPotentialHole(rhs);
-
     conversionsOrFixes.push_back(CollectionElementContextualMismatch::create(
         *this, lhs, rhs, getConstraintLocator(locator)));
     break;
@@ -6737,9 +6775,6 @@ bool ConstraintSystem::repairFailures(
 
   case ConstraintLocator::TernaryBranch:
   case ConstraintLocator::SingleValueStmtResult: {
-    recordAnyTypeVarAsPotentialHole(lhs);
-    recordAnyTypeVarAsPotentialHole(rhs);
-
     if (lhs->hasPlaceholder() || rhs->hasPlaceholder())
       return true;
 
@@ -6807,8 +6842,6 @@ bool ConstraintSystem::repairFailures(
       return true;
 
     if (isMemberMatch) {
-      recordAnyTypeVarAsPotentialHole(lhs);
-      recordAnyTypeVarAsPotentialHole(rhs);
       conversionsOrFixes.push_back(AllowAssociatedValueMismatch::create(
           *this, lhs, rhs, getConstraintLocator(locator)));
       break;
@@ -6856,9 +6889,28 @@ bool ConstraintSystem::repairFailures(
     if (!path.empty() && path.back().is<LocatorPathElt::PackElement>())
       path.pop_back();
 
-    if (!path.empty() && path.back().is<LocatorPathElt::AnyRequirement>()) {
-      return repairFailures(lhs, rhs, matchKind, flags, conversionsOrFixes,
-                            getConstraintLocator(anchor, path));
+    if (!path.empty()) {
+      if (path.back().is<LocatorPathElt::AnyRequirement>()) {
+        return repairFailures(lhs, rhs, matchKind, flags, conversionsOrFixes,
+                              getConstraintLocator(anchor, path));
+      }
+
+      if (auto argConv = path.back().getAs<LocatorPathElt::ApplyArgToParam>()) {
+        auto argIdx = argConv->getArgIdx();
+        auto paramIdx = argConv->getParamIdx();
+
+        auto *argLoc = getConstraintLocator(anchor, path);
+        if (auto overload = findSelectedOverloadFor(getCalleeLocator(argLoc))) {
+          auto *overloadTy =
+              simplifyType(overload->boundType)->castTo<FunctionType>();
+          auto *argList = getArgumentList(argLoc);
+          ASSERT(argList);
+          conversionsOrFixes.push_back(AllowArgumentMismatch::create(
+              *this, getType(argList->getExpr(argIdx)),
+              overloadTy->getParams()[paramIdx].getPlainType(), argLoc));
+          return true;
+        }
+      }
     }
 
     // When the solver sets `TMF_MatchingGenericArguments` it means
@@ -6915,12 +6967,19 @@ bool ConstraintSystem::repairFailures(
     path.pop_back();
 
     ConstraintFix *fix = nullptr;
-    if (!path.empty() && path.back().is<LocatorPathElt::AnyRequirement>()) {
+    auto *fixLoc = getConstraintLocator(anchor, path);
+
+    if (fixLoc->isLastElement<LocatorPathElt::AnyRequirement>()) {
       fix = fixRequirementFailure(*this, fromType, toType, anchor, path);
+    } else if (fixLoc->isLastElement<LocatorPathElt::TupleElement>()) {
+      return repairFailures(lhs, rhs, matchKind, flags, conversionsOrFixes,
+                            fixLoc);
+    } else if (!lhs->mayHaveSuperclass() && rhs->isAnyObject()) {
+      fix = AllowNonClassTypeToConvertToAnyObject::create(*this, fromType,
+                                                          fixLoc);
     } else {
       fix = GenericArgumentsMismatch::create(
-          *this, fromType, toType, {genericArgElt.getIndex()},
-          getConstraintLocator(anchor, path));
+          *this, fromType, toType, {genericArgElt.getIndex()}, fixLoc);
     }
 
     if (!fix)
@@ -6952,6 +7011,13 @@ bool ConstraintSystem::repairFailures(
   }
 
   case ConstraintLocator::CoercionOperand: {
+    // If either type is a placeholder, consider this fixed, eagerly propagating
+    // a hole from the contextual type.
+    if (lhs->isPlaceholder() || rhs->isPlaceholder()) {
+      tryPropagateHole(rhs, lhs);
+      return true;
+    }
+
     auto *coercion = castToExpr<CoerceExpr>(anchor);
 
     // Coercion from T.Type to T.Protocol.
@@ -7033,6 +7099,20 @@ static bool isTupleWithUnresolvedPackExpansion(Type type) {
   return false;
 }
 
+static bool isDependentMemberTypeWithBaseThatContainsUnresolvedPackExpansions(
+    ConstraintSystem &cs, Type type) {
+  if (!type->is<DependentMemberType>())
+    return false;
+
+  auto baseTy = cs.getFixedTypeRecursive(type->getDependentMemberRoot(),
+                                         /*wantRValue=*/true);
+  llvm::SmallPtrSet<TypeVariableType *, 2> typeVars;
+  baseTy->getTypeVariables(typeVars);
+  return llvm::any_of(typeVars, [](const TypeVariableType *typeVar) {
+    return typeVar->getImpl().isPackExpansion();
+  });
+}
+
 ConstraintSystem::TypeMatchResult
 ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
                              TypeMatchOptions flags,
@@ -7069,7 +7149,7 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
   //
   // along any unsolved path. No other returns should produce
   // SolutionKind::Unsolved or inspect TMF_GenerateConstraints.
-  auto formUnsolvedResult = [&] {
+  auto formUnsolvedResult = [&](bool useOriginalTypes = false) {
     // If we're supposed to generate constraints (i.e., this is a
     // newly-generated constraint), do so now.
     if (flags.contains(TMF_GenerateConstraints)) {
@@ -7078,8 +7158,13 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
       // this new constraint will be solved at a later point.
       // Obviously, this must not happen at the top level, or the
       // algorithm would not terminate.
-      addUnsolvedConstraint(Constraint::create(*this, kind, type1, type2,
-                                               getConstraintLocator(locator)));
+      if (useOriginalTypes) {
+        addUnsolvedConstraint(Constraint::create(
+            *this, kind, origType1, origType2, getConstraintLocator(locator)));
+      } else {
+        addUnsolvedConstraint(Constraint::create(
+            *this, kind, type1, type2, getConstraintLocator(locator)));
+      }
       return getTypeMatchSuccess();
     }
 
@@ -7300,16 +7385,27 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
   // match `$T3` and propagate `Pack{Int}` to `$T2`.
   //
   // This is also important for situations like: `$T2 conv (Int, $T_exp)`
-  // becuase expansion could be defaulted to an empty pack which means
+  // because expansion could be defaulted to an empty pack which means
   // that under substitution that element would disappear and the type
   // would be just `(Int)`.
   //
-  // Notable exception here is `Any` which doesn't require wrapping and
-  // would be handled by existental promotion in cases where it's allowed.
+  // Notable exceptions here are: `Any` which doesn't require wrapping and
+  // would be handled by an existential promotion in cases where it's allowed,
+  // and `Optional<T>` which would be handled by optional injection.
   if (isTupleWithUnresolvedPackExpansion(origType1) ||
       isTupleWithUnresolvedPackExpansion(origType2)) {
-    if (desugar1->is<TupleType>() != desugar2->is<TupleType>() &&
-        (!desugar1->isAny() && !desugar2->isAny())) {
+    auto isTypeVariableWrappedInOptional = [](Type type) {
+      if (type->getOptionalObjectType()) {
+        return type->lookThroughAllOptionalTypes()->isTypeVariableOrMember();
+      }
+      return false;
+    };
+    if (isa<TupleType>(desugar1) != isa<TupleType>(desugar2) &&
+        !isa<InOutType>(desugar1) && !isa<InOutType>(desugar2) &&
+        !isTypeVariableWrappedInOptional(desugar1) &&
+        !isTypeVariableWrappedInOptional(desugar2) &&
+        !desugar1->isAny() &&
+        !desugar2->isAny()) {
       return matchTypes(
           desugar1->is<TupleType>() ? type1
                                     : TupleType::get({type1}, getASTContext()),
@@ -7319,6 +7415,29 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
     }
   }
 
+  // Dependent members cannot be simplified if base type contains unresolved
+  // pack expansion type variables because they don't give enough information
+  // to substitution logic to form a correct type. For example:
+  //
+  // ```
+  // protocol P { associatedtype V }
+  // struct S<each T> : P { typealias V = (repeat (each T)?) }
+  // ```
+  //
+  // If pack expansion is represented as `$T1` and its pattern is `$T2`, a
+  // reference to `V` would get a type `S<Pack{$T}>.V` and simplified version
+  // would be `Optional<Pack{$T1}>` instead of `Pack{repeat Optional<$T2>}`
+  // because `$T1` is treated as a substitution for `each T` until bound.
+  if (isDependentMemberTypeWithBaseThatContainsUnresolvedPackExpansions(
+          *this, origType1) ||
+      isDependentMemberTypeWithBaseThatContainsUnresolvedPackExpansions(
+          *this, origType2)) {
+    // It's important to preserve the original types here because any attempt
+    // at simplification or canonicalization wouldn't produce a correct type
+    // util pack expansion type variables are bound.
+    return formUnsolvedResult(/*useOriginalTypes=*/true);
+  }
+
   llvm::SmallVector<RestrictionOrFix, 4> conversionsOrFixes;
 
   // Decompose parallel structure.
@@ -7341,14 +7460,31 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
 
     // Note: Mismatched builtin types fall through to the TypeKind::Error
     // case below.
+#define BUILTIN_GENERIC_TYPE(id, parent)
 #define BUILTIN_TYPE(id, parent) case TypeKind::id:
 #define TYPE(id, parent)
 #include "swift/AST/TypeNodes.def"
 
     case TypeKind::Error:
-    case TypeKind::Unresolved:
       return getTypeMatchFailure(locator);
 
+    case TypeKind::BuiltinFixedArray: {
+      auto *fixed1 = cast<BuiltinFixedArrayType>(desugar1);
+      auto *fixed2 = cast<BuiltinFixedArrayType>(desugar2);
+
+      auto result = matchTypes(fixed1->getSize(), fixed2->getSize(),
+                               ConstraintKind::Bind, subflags,
+                               locator.withPathElement(
+                                   LocatorPathElt::GenericArgument(0)));
+      if (result.isFailure())
+        return result;
+
+      return matchTypes(fixed1->getElementType(), fixed2->getElementType(),
+                        ConstraintKind::Bind, subflags,
+                        locator.withPathElement(
+                            LocatorPathElt::GenericArgument(0)));
+    }
+
     case TypeKind::Placeholder: {
       // If it's allowed to attempt fixes, let's delegate
       // decision to `repairFailures`, since depending on
@@ -7992,7 +8128,7 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
               if (inoutBaseType->isTypeVariableOrMember())
                 return formUnsolvedResult();
 
-              auto baseIsArray = inoutBaseType->isArrayType();
+              auto baseIsArray = inoutBaseType->isArray();
 
               if (baseIsArray)
                 conversionsOrFixes.push_back(
@@ -8010,7 +8146,8 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
                 // for imported declarations.
                 if (isArgumentOfImportedDecl(locator)) {
                   conversionsOrFixes.push_back(
-                      ConversionRestrictionKind::InoutToCPointer);
+                      baseIsArray ? ConversionRestrictionKind::ArrayToCPointer
+                                  : ConversionRestrictionKind::InoutToCPointer);
                 }
               }
             }
@@ -8061,7 +8198,7 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
             if (pointerKind == PTK_UnsafePointer
                 || pointerKind == PTK_UnsafeRawPointer) {
               if (!isAutoClosureArgument) {
-                if (type1->isArrayType()) {
+                if (type1->isArray()) {
                   conversionsOrFixes.push_back(
                       ConversionRestrictionKind::ArrayToPointer);
 
@@ -8357,7 +8494,6 @@ ConstraintSystem::simplifyConstructionConstraint(
   case TypeKind::BuiltinTuple:
     llvm_unreachable("BuiltinTupleType in constraint");
     
-  case TypeKind::Unresolved:
   case TypeKind::Error:
   case TypeKind::Placeholder:
     return SolutionKind::Error;
@@ -8656,7 +8792,36 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyConformsToConstraint(
     return SolutionKind::Solved;
   }
 
-  return matchExistentialTypes(type, protocol, kind, flags, locator);
+  auto result = matchExistentialTypes(type, protocol, kind, flags, locator);
+
+  if (shouldAttemptFixes() && result.isFailure()) {
+    auto *loc = getConstraintLocator(locator);
+
+    ArrayRef<LocatorPathElt> path = loc->getPath();
+    while (!path.empty()) {
+      if (!path.back().is<LocatorPathElt::InstanceType>())
+        break;
+
+      path = path.drop_back();
+    }
+
+    if (path.size() != loc->getPath().size()) {
+      loc = getConstraintLocator(loc->getAnchor(), path);
+    }
+
+    ConstraintFix *fix = nullptr;
+    if (loc->isLastElement<LocatorPathElt::ApplyArgToParam>()) {
+      fix = AllowArgumentMismatch::create(*this, type, protocol, loc);
+    } else if (loc->isLastElement<LocatorPathElt::ContextualType>()) {
+      fix = ContextualMismatch::create(*this, type, protocol, loc);
+    }
+
+    if (fix) {
+      return recordFix(fix) ? SolutionKind::Error : SolutionKind::Solved;
+    }
+  }
+
+  return result;
 }
 
 void ConstraintSystem::recordSynthesizedConformance(
@@ -9030,6 +9195,13 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyConformsToConstraint(
         continue;
       }
 
+      // Matching existentials could introduce constraints with `instance type`
+      // element at the end if the confirming type wasn't fully resolved.
+      if (path.back().is<LocatorPathElt::InstanceType>()) {
+        path.pop_back();
+        continue;
+      }
+
       break;
     }
 
@@ -9123,7 +9295,7 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyConformsToConstraint(
       }
     }
 
-    if (loc->isLastElement<LocatorPathElt::MemberRefBase>()) {
+    if (path.back().is<LocatorPathElt::MemberRefBase>()) {
       auto *fix = ContextualMismatch::create(*this, protocolTy, type, loc);
       if (!recordFix(fix))
         return SolutionKind::Solved;
@@ -9133,7 +9305,7 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyConformsToConstraint(
     // for example to `AnyHashable`.
     if ((kind == ConstraintKind::ConformsTo ||
          kind == ConstraintKind::NonisolatedConformsTo) &&
-        loc->isLastElement<LocatorPathElt::ApplyArgToParam>()) {
+        path.back().is<LocatorPathElt::ApplyArgToParam>()) {
       auto *fix = AllowArgumentMismatch::create(*this, type, protocolTy, loc);
       return recordFix(fix, /*impact=*/2) ? SolutionKind::Error
                                           : SolutionKind::Solved;
@@ -9142,9 +9314,10 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyConformsToConstraint(
     // If this is an implicit Hashable conformance check generated for each
     // index argument of the keypath subscript component, we could just treat
     // it as though it conforms.
-    if ((loc->isResultOfKeyPathDynamicMemberLookup() ||
-         loc->isKeyPathSubscriptComponent()) ||
-        loc->isKeyPathMemberComponent()) {
+    if (loc->isResultOfKeyPathDynamicMemberLookup() ||
+        loc->isKeyPathSubscriptComponent() ||
+        loc->isKeyPathMemberComponent() ||
+        loc->isKeyPathApplyComponent()) {
       if (protocol ==
           getASTContext().getProtocol(KnownProtocolKind::Hashable)) {
         auto *fix =
@@ -9263,7 +9436,7 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyTransitivelyConformsTo(
     }
 
     // Array<T> -> Unsafe{Raw}Pointer<T>
-    if (auto elt = resolvedTy->isArrayType()) {
+    if (auto elt = resolvedTy->getArrayElementType()) {
       typesToCheck.push_back(getPointerFor(PTK_UnsafePointer, elt));
       typesToCheck.push_back(getPointerFor(PTK_UnsafeRawPointer, elt));
     }
@@ -9294,7 +9467,7 @@ static CheckedCastKind getCheckedCastKind(ConstraintSystem *cs,
                                           Type fromType,
                                           Type toType) {
   // Array downcasts are handled specially.
-  if (fromType->isArrayType() && toType->isArrayType()) {
+  if (fromType->isArray() && toType->isArray()) {
     return CheckedCastKind::ArrayDowncast;
   }
 
@@ -9332,10 +9505,12 @@ static ConstraintFix *maybeWarnAboutExtraneousCast(
   if (locator.endsWith<LocatorPathElt::GenericArgument>())
     return nullptr;
 
-  // Both types have to be fixed.
-  if (fromType->hasTypeVariable() || toType->hasTypeVariable() ||
-      fromType->hasPlaceholder() || toType->hasPlaceholder())
+  // Both types have to be resolved, `typeCheckCheckedCast` doesn't support
+  // checking solver-allocated types.
+  if (fromType->hasTypeVariableOrPlaceholder() ||
+      toType->hasTypeVariableOrPlaceholder()) {
     return nullptr;
+  }
 
   SmallVector<LocatorPathElt, 4> path;
   auto anchor = locator.getLocatorParts(path);
@@ -9558,8 +9733,8 @@ ConstraintSystem::simplifyCheckedCastConstraint(
   auto kind = getCheckedCastKind(this, fromType, toType);
   switch (kind) {
   case CheckedCastKind::ArrayDowncast: {
-    auto fromBaseType = fromType->isArrayType();
-    auto toBaseType = toType->isArrayType();
+    auto fromBaseType = fromType->getArrayElementType();
+    auto toBaseType = toType->getArrayElementType();
 
     auto elementLocator =
         locator.withPathElement(LocatorPathElt::GenericArgument(0));
@@ -10009,8 +10184,7 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
 
   MemberLookupResult result;
 
-  if (instanceTy->isTypeVariableOrMember() ||
-      instanceTy->is<UnresolvedType>()) {
+  if (instanceTy->isTypeVariableOrMember()) {
     result.OverallResult = MemberLookupResult::Unsolved;
     return result;
   }
@@ -10148,13 +10322,15 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
         if (path.back().getKind() == ConstraintLocator::ConstructorMember)
           isImplicitInit = true;
 
-      if (auto *applyExpr = getAsExpr<ApplyExpr>(anchor)) {
-        if (auto *argExpr = applyExpr->getArgs()->getUnlabeledUnaryExpr()) {
-          favoredType = getFavoredType(argExpr);
-
-          if (!favoredType) {
-            optimizeConstraints(argExpr);
+      if (performanceHacksEnabled()) {
+        if (auto *applyExpr = getAsExpr<ApplyExpr>(anchor)) {
+          if (auto *argExpr = applyExpr->getArgs()->getUnlabeledUnaryExpr()) {
             favoredType = getFavoredType(argExpr);
+
+            if (!favoredType) {
+              optimizeConstraints(argExpr);
+              favoredType = getFavoredType(argExpr);
+            }
           }
         }
       }
@@ -10195,6 +10371,55 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
   // have already been excluded.
   llvm::SmallPtrSet<ValueDecl *, 2> excludedDynamicMembers;
 
+  // Delay solving member constraint for unapplied methods
+  // where the base type has a conditional Sendable conformance
+  auto shouldDelayDueToPartiallyResolvedBaseType =
+      [&](Type baseTy, ValueDecl *decl,
+          FunctionRefInfo functionRefInfo) -> bool {
+    if (!Context.LangOpts.hasFeature(Feature::InferSendableFromCaptures))
+      return false;
+
+    if (!Context.getProtocol(KnownProtocolKind::Sendable))
+      return false;
+
+    auto shouldCheckSendabilityOfBase = [&]() {
+      if (!isa_and_nonnull<FuncDecl>(decl))
+        return Type();
+
+      if (!decl->isInstanceMember() &&
+          !decl->getDeclContext()->getSelfProtocolDecl())
+        return Type();
+
+      auto hasAppliedSelf =
+          decl->hasCurriedSelf() && doesMemberRefApplyCurriedSelf(baseTy, decl);
+      auto numApplies = getNumApplications(hasAppliedSelf, functionRefInfo);
+      if (numApplies >= decl->getNumCurryLevels())
+        return Type();
+
+      return decl->isInstanceMember() ? baseTy->getMetatypeInstanceType()
+                                      : baseTy;
+    };
+
+    Type baseTyToCheck = shouldCheckSendabilityOfBase();
+    if (!baseTyToCheck)
+      return false;
+
+    auto sendableProtocol = Context.getProtocol(KnownProtocolKind::Sendable);
+    auto baseConformance = lookupConformance(baseTyToCheck, sendableProtocol);
+
+    return llvm::any_of(baseConformance.getConditionalRequirements(),
+                        [&](const auto &req) {
+                          if (req.getKind() != RequirementKind::Conformance)
+                            return false;
+
+                          return (req.getFirstType()->hasTypeVariable() &&
+                                  (req.getProtocolDecl()->isSpecificProtocol(
+                                       KnownProtocolKind::Sendable) ||
+                                   req.getProtocolDecl()->isSpecificProtocol(
+                                       KnownProtocolKind::SendableMetatype)));
+                        });
+  };
+
   // Local function that adds the given declaration if it is a
   // reasonable choice.
   auto addChoice = [&](OverloadChoice candidate) {
@@ -10221,6 +10446,12 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
     auto baseTy = candidate.getBaseType();
     const auto baseObjTy = baseTy->getRValueType();
 
+    // If we need to delay, update the status but record the member.
+    if (shouldDelayDueToPartiallyResolvedBaseType(
+            baseObjTy, decl, candidate.getFunctionRefInfo())) {
+      result.OverallResult = MemberLookupResult::Unsolved;
+    }
+
     bool hasInstanceMembers = false;
     bool hasInstanceMethods = false;
     bool hasStaticMembers = false;
@@ -10269,44 +10500,57 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
     // If the invocation's argument expression has a favored type,
     // use that information to determine whether a specific overload for
     // the candidate should be favored.
-    if (isa<ConstructorDecl>(decl) && favoredType &&
-        result.FavoredChoice == ~0U) {
-      auto *ctor = cast<ConstructorDecl>(decl);
-
-      // Only try and favor monomorphic unary initializers.
-      if (!ctor->isGenericContext()) {
-        if (!ctor->getMethodInterfaceType()->hasError()) {
-          // The constructor might have an error type because we don't skip
-          // invalid decls for code completion
-          auto args = ctor->getMethodInterfaceType()
-                          ->castTo<FunctionType>()
-                          ->getParams();
-          if (args.size() == 1 && !args[0].hasLabel() &&
-              args[0].getPlainType()->isEqual(favoredType)) {
-            if (!isDeclUnavailable(decl, memberLocator))
-              result.FavoredChoice = result.ViableCandidates.size();
+    if (performanceHacksEnabled()) {
+      if (isa<ConstructorDecl>(decl) && favoredType &&
+          result.FavoredChoice == ~0U) {
+        auto *ctor = cast<ConstructorDecl>(decl);
+
+        // Only try and favor monomorphic unary initializers.
+        if (!ctor->isGenericContext()) {
+          if (!ctor->getMethodInterfaceType()->hasError()) {
+            // The constructor might have an error type because we don't skip
+            // invalid decls for code completion
+            auto args = ctor->getMethodInterfaceType()
+                            ->castTo<FunctionType>()
+                            ->getParams();
+            if (args.size() == 1 && !args[0].hasLabel() &&
+                args[0].getPlainType()->isEqual(favoredType)) {
+              if (!isDeclUnavailable(decl, memberLocator))
+                result.FavoredChoice = result.ViableCandidates.size();
+            }
           }
         }
       }
     }
 
     const auto isUnsupportedExistentialMemberAccess = [&] {
+      if (!instanceTy->isExistentialType())
+        return false;
+
+      // If the base type is composed with marker protocol(s) i.e.
+      // `<<Type>> & Sendable`, let's skip this check because such
+      // compositions are always opened and simplified down to a
+      // superclass bound post-Sema.
+      if (auto *existential = instanceTy->getAs<ExistentialType>()) {
+        auto *compositionTy =
+            existential->getConstraintType()->getAs<ProtocolCompositionType>();
+        if (compositionTy &&
+            !compositionTy->withoutMarkerProtocols()->isExistentialType())
+          return false;
+      }
+
       // We may not be able to derive a well defined type for an existential
       // member access if the member's signature references 'Self'.
-      if (instanceTy->isExistentialType()) {
-        switch (isMemberAvailableOnExistential(instanceTy, decl)) {
-        case ExistentialMemberAccessLimitation::Unsupported:
-        // TODO: Write-only accesses are not supported yet.
-        case ExistentialMemberAccessLimitation::WriteOnly:
-          return true;
+      switch (isMemberAvailableOnExistential(instanceTy, decl)) {
+      case ExistentialMemberAccessLimitation::Unsupported:
+      // TODO: Write-only accesses are not supported yet.
+      case ExistentialMemberAccessLimitation::WriteOnly:
+        return true;
 
-        case ExistentialMemberAccessLimitation::ReadOnly:
-        case ExistentialMemberAccessLimitation::None:
-          break;
-        }
+      case ExistentialMemberAccessLimitation::ReadOnly:
+      case ExistentialMemberAccessLimitation::None:
+        return false;
       }
-
-      return false;
     };
 
     // See if we have an instance method, instance member or static method,
@@ -10321,8 +10565,8 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
         auto choice =
             instanceTy->isAnyObject()
                 ? candidate
-                : OverloadChoice(instanceTy, decl,
-                                 FunctionRefInfo::singleBaseNameApply());
+                : OverloadChoice::getDecl(instanceTy, decl,
+                                          FunctionRefInfo::singleBaseNameApply());
 
         const bool invalidMethodRef = isa<FuncDecl>(decl) && !hasInstanceMethods;
         const bool invalidMemberRef = !isa<FuncDecl>(decl) && !hasInstanceMembers;
@@ -10557,51 +10801,9 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
       }
     }
 
-    return OverloadChoice(baseTy, cand, functionRefInfo);
+    return OverloadChoice::getDecl(baseTy, cand, functionRefInfo);
   };
 
-  // Delay solving member constraint for unapplied methods
-  // where the base type has a conditional Sendable conformance
-  if (Context.LangOpts.hasFeature(Feature::InferSendableFromCaptures)) {
-    auto shouldCheckSendabilityOfBase = [&]() {
-      if (!Context.getProtocol(KnownProtocolKind::Sendable))
-        return false;
-
-      return llvm::any_of(lookup, [&](const auto &result) {
-        auto decl = result.getValueDecl();
-        if (!isa_and_nonnull<FuncDecl>(decl))
-          return false;
-
-        if (!decl->isInstanceMember())
-          return false;
-
-        auto hasAppliedSelf = decl->hasCurriedSelf() &&
-                              doesMemberRefApplyCurriedSelf(baseObjTy, decl);
-        auto numApplies = getNumApplications(hasAppliedSelf, functionRefInfo);
-        return numApplies < decl->getNumCurryLevels();
-      });
-    };
-
-    if (shouldCheckSendabilityOfBase()) {
-      auto sendableProtocol = Context.getProtocol(KnownProtocolKind::Sendable);
-      auto baseConformance = lookupConformance(instanceTy, sendableProtocol);
-
-      if (llvm::any_of(
-              baseConformance.getConditionalRequirements(),
-              [&](const auto &req) {
-                if (req.getKind() != RequirementKind::Conformance)
-                  return false;
-
-                return (req.getFirstType()->hasTypeVariable() &&
-                        req.getProtocolDecl()->isSpecificProtocol(
-                            KnownProtocolKind::Sendable));
-              })) {
-        result.OverallResult = MemberLookupResult::Unsolved;
-        return result;
-      }
-    }
-  }
-
   // Add all results from this lookup.
   for (auto result : lookup)
     addChoice(getOverloadChoice(result.getValueDecl(),
@@ -11400,6 +11602,14 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyMemberConstraint(
             // `key path` constraint can't be retired until all components
             // are simplified.
             addTypeVariableConstraintsToWorkList(memberTypeVar);
+          } else if (isa<Expr *>(locator->getAnchor()) &&
+                     !getSemanticsProvidingParentExpr(
+                         getAsExpr(locator->getAnchor()))) {
+            // If there are no contextual expressions that could provide
+            // a type for the member type variable, let's default it to
+            // a placeholder eagerly so it could be propagated to the
+            // pattern if necessary.
+            recordTypeVariablesAsHoles(memberTypeVar);
           } else if (locator->isLastElement<LocatorPathElt::PatternMatch>()) {
             // Let's handle member patterns specifically because they use
             // equality instead of argument application constraint, so allowing
@@ -11726,13 +11936,14 @@ ConstraintSystem::simplifyValueWitnessConstraint(
     return formUnsolved();
 
   auto witness =
-      conformance.getWitnessByName(baseObjectType, requirement->getName());
+      conformance.getWitnessByName(requirement->getName());
   if (!witness)
     return fail();
 
-  auto choice = OverloadChoice(resolvedBaseType, witness.getDecl(), functionRefInfo);
-  resolveOverload(getConstraintLocator(locator), memberType, choice,
-                  useDC);
+  auto choice = OverloadChoice::getDecl(
+      resolvedBaseType, witness.getDecl(), functionRefInfo);
+  addBindOverloadConstraint(memberType, choice, getConstraintLocator(locator),
+                            useDC);
   return SolutionKind::Solved;
 }
 
@@ -11962,8 +12173,10 @@ static Type getOpenedResultBuilderTypeFor(ConstraintSystem &cs,
     // Find the opened type for this callee and substitute in the type
     // parameters.
     auto substitutions = cs.getOpenedTypes(calleeLocator);
-    if (!substitutions.empty())
-      builderType = cs.openType(builderType, substitutions, locator);
+    if (!substitutions.empty()) {
+      builderType = cs.openType(builderType, substitutions, locator,
+                                /*preparedOverload=*/nullptr);
+    }
 
     assert(!builderType->hasTypeParameter());
   }
@@ -12406,8 +12619,24 @@ ConstraintSystem::simplifyDynamicTypeOfConstraint(
                       locator);
   }
 
-  // It's definitely not either kind of metatype, so we can
-  // report failure right away.
+  // We don't have a non-metatype result, produce a fix.
+  if (shouldAttemptFixes()) {
+    // If we have a hole as a contextual type, eagerly produce holes in the
+    // argument of `type(of:)`.
+    if (type1->isPlaceholder()) {
+      recordTypeVariablesAsHoles(type2);
+      return SolutionKind::Solved;
+    }
+
+    // Otherwise we have some invalid contextual type, record a fix and let the
+    // argument be turned into a hole if needed.
+    recordAnyTypeVarAsPotentialHole(type2);
+
+    recordFix(IgnoreNonMetatypeDynamicType::create(
+        *this, type2, type1, getConstraintLocator(locator)));
+    return SolutionKind::Solved;
+  }
+
   return SolutionKind::Error;
 }
 
@@ -12548,8 +12777,8 @@ ConstraintSystem::simplifyBridgingConstraint(Type type1,
   };
 
   // Bridging the elements of an array.
-  if (auto fromElement = unwrappedFromType->isArrayType()) {
-    if (auto toElement = unwrappedToType->isArrayType()) {
+  if (auto fromElement = unwrappedFromType->getArrayElementType()) {
+    if (auto toElement = unwrappedToType->getArrayElementType()) {
       countOptionalInjections();
       auto result = simplifyBridgingConstraint(
           fromElement, toElement, subflags,
@@ -12833,8 +13062,29 @@ ConstraintSystem::simplifyKeyPathConstraint(
       auto paramFnTy = FunctionType::get(paramParam, fnTy->getResult(),
                                          fnTy->getExtInfo());
 
+      // Form a key path type as well to make sure that root and value
+      // types satisfy all of its requirements.
+      // Note that `KeyPath` types used to have no requirements but now
+      // they do require `Root` and `Value` to be `Copyable` and `Escapable`.
+      {
+        auto keyPathTy =
+            openUnboundGenericType(
+                getASTContext().getKeyPathDecl(),
+                /*parent=*/Type(),
+                locator.withPathElement(LocatorPathElt::KeyPathType()),
+                /*isTypeResolution=*/false)
+                ->castTo<BoundGenericType>();
+        addConstraint(ConstraintKind::Bind, keyPathTy->getGenericArgs()[0],
+                      rootTy,
+                      locator.withPathElement(LocatorPathElt::KeyPathRoot()));
+        addConstraint(ConstraintKind::Bind, keyPathTy->getGenericArgs()[1],
+                      valueTy,
+                      locator.withPathElement(LocatorPathElt::KeyPathValue()));
+      }
+
       return !matchTypes(kpFnTy, paramFnTy, ConstraintKind::Conversion,
-                         subflags, locator).isFailure();
+                         subflags, locator)
+                  .isFailure();
     }
 
     assert(contextualRootTy && contextualValueTy);
@@ -13089,18 +13339,14 @@ bool ConstraintSystem::simplifyAppliedOverloadsImpl(
 
   /// The common result type amongst all function overloads.
   Type commonResultType;
-  auto updateCommonResultType = [&](Type choiceType) {
-    auto markFailure = [&] {
-      commonResultType = ErrorType::get(getASTContext());
-    };
 
-    auto choiceFnType = choiceType->getAs<FunctionType>();
-    if (!choiceFnType)
-      return markFailure();
+  auto markFailure = [&] {
+    commonResultType = ErrorType::get(getASTContext());
+  };
 
+  auto updateCommonResultType = [&](Type choiceResultType) {
     // For now, don't attempt to establish a common result type when there
     // are type parameters.
-    Type choiceResultType = choiceFnType->getResult();
     if (choiceResultType->hasTypeParameter())
       return markFailure();
 
@@ -13238,8 +13484,32 @@ bool ConstraintSystem::simplifyAppliedOverloadsImpl(
             choiceType = objectType;
         }
 
-        // If we have a function type, we can compute a common result type.
-        updateCommonResultType(choiceType);
+        // FIXME: The !getSelfProtocolDecl() check is load-bearing, because
+        // this optimization interacts poorly with existential opening
+        // somehow. It should all be removed.
+        if (auto *choiceFnType = choiceType->getAs<FunctionType>()) {
+          if (isa<ConstructorDecl>(choice.getDecl()) &&
+              !choice.getDecl()->getDeclContext()->getSelfProtocolDecl()) {
+            auto choiceResultType = choice.getBaseType()
+                                        ->getRValueType()
+                                        ->getMetatypeInstanceType();
+
+            if (choiceResultType->getOptionalObjectType()) {
+              hasUnhandledConstraints = true;
+              return true;
+            }
+
+            if (choiceFnType->getResult()->getOptionalObjectType())
+              choiceResultType = OptionalType::get(choiceResultType);
+
+            updateCommonResultType(choiceResultType);
+          } else {
+            updateCommonResultType(choiceFnType->getResult());
+          }
+        } else {
+          markFailure();
+        }
+
         return true;
       });
 
@@ -13263,12 +13533,9 @@ bool ConstraintSystem::simplifyAppliedOverloadsImpl(
   // If we have a common result type, bind the expected result type to it.
   if (commonResultType && !commonResultType->is<ErrorType>()) {
     if (isDebugMode()) {
-      PrintOptions PO;
-      PO.PrintTypesForDebugging = true;
       llvm::errs().indent(solverState ? solverState->getCurrentIndent() : 0)
-        << "(common result type for $T" << fnTypeVar->getID() << " is "
-        << commonResultType.getString(PO)
-        << ")\n";
+          << "(common result type for $T" << fnTypeVar->getID() << " is "
+          << commonResultType.getString(PrintOptions::forDebugging()) << ")\n";
     }
 
     // Introduction of a `Bind` constraint here could result in the disconnect
@@ -13935,8 +14202,8 @@ ConstraintSystem::simplifyDynamicCallableApplicableFnConstraint(
   SmallVector<OverloadChoice, 4> choices;
   for (auto candidate : candidates) {
     if (candidate->isInvalid()) continue;
-    choices.push_back(OverloadChoice(type2, candidate,
-                                     FunctionRefInfo::singleBaseNameApply()));
+    choices.push_back(OverloadChoice::getDecl(type2, candidate,
+                                              FunctionRefInfo::singleBaseNameApply()));
   }
 
   if (choices.empty()) {
@@ -14828,7 +15095,7 @@ ConstraintSystem::simplifyRestrictedConstraintImpl(
     
     auto t2 = type2->getDesugaredType();
 
-    auto baseType1 = getFixedTypeRecursive(obj1->isArrayType(), false);
+    auto baseType1 = getFixedTypeRecursive(obj1->getArrayElementType(), false);
     auto ptr2 = getBaseTypeForPointer(t2);
 
     increaseScore(SK_ValueToOptional, locator, ptr2.getInt());
@@ -14931,7 +15198,7 @@ ConstraintSystem::simplifyRestrictedConstraintImpl(
 
     increaseScore(SK_ValueToPointerConversion, locator);
 
-    type1 = getFixedTypeRecursive(type1->getInOutObjectType()->isArrayType(),
+    type1 = getFixedTypeRecursive(type1->getInOutObjectType()->getArrayElementType(),
                                   /*wantRValue=*/false);
     LLVM_FALLTHROUGH;
   }
@@ -14967,8 +15234,8 @@ ConstraintSystem::simplifyRestrictedConstraintImpl(
 
   // T < U or T is bridged to V where V < U ===> Array<T> <c Array<U>
   case ConversionRestrictionKind::ArrayUpcast: {
-    Type baseType1 = type1->isArrayType();
-    Type baseType2 = type2->isArrayType();
+    Type baseType1 = type1->getArrayElementType();
+    Type baseType2 = type2->getArrayElementType();
 
     increaseScore(SK_CollectionUpcastConversion, locator);
     return matchTypes(baseType1,
@@ -15100,9 +15367,19 @@ ConstraintSystem::simplifyRestrictedConstraintImpl(
         restriction == ConversionRestrictionKind::CGFloatToDouble ? 2 : 10;
 
     if (restriction == ConversionRestrictionKind::DoubleToCGFloat) {
-      if (auto *anchor = locator.trySimplifyToExpr()) {
-        if (auto depth = getExprDepth(anchor))
-          impact = (*depth + 1) * impact;
+      SmallVector<LocatorPathElt> originalPath;
+      auto anchor = locator.getLocatorParts(originalPath);
+
+      SourceRange range;
+      ArrayRef<LocatorPathElt> path(originalPath);
+      simplifyLocator(anchor, path, range);
+
+      if (path.empty() || llvm::all_of(path, [](const LocatorPathElt &elt) {
+            return elt.is<LocatorPathElt::OptionalInjection>();
+          })) {
+        if (auto *expr = getAsExpr(anchor))
+          if (auto depth = getExprDepth(expr))
+            impact = (*depth + 1) * impact;
       }
     } else if (locator.directlyAt<AssignExpr>() ||
                locator.endsWith<LocatorPathElt::ContextualType>()) {
@@ -15306,7 +15583,16 @@ static bool isAugmentingFix(ConstraintFix *fix) {
   }
 }
 
-bool ConstraintSystem::recordFix(ConstraintFix *fix, unsigned impact) {
+bool ConstraintSystem::recordFix(ConstraintFix *fix, unsigned impact,
+                                 PreparedOverloadBuilder *preparedOverload) {
+  if (preparedOverload) {
+    ASSERT(PreparingOverload);
+    preparedOverload->addedFix(fix, impact);
+    return true;
+  }
+
+  ASSERT(!PreparingOverload);
+
   if (isDebugMode()) {
     auto &log = llvm::errs();
     log.indent(solverState ? solverState->getCurrentIndent() : 0)
@@ -15639,7 +15925,8 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyFixConstraint(
   case FixKind::AllowFunctionSpecialization:
   case FixKind::IgnoreGenericSpecializationArityMismatch:
   case FixKind::IgnoreKeyPathSubscriptIndexMismatch:
-  case FixKind::AllowMemberRefOnExistential: {
+  case FixKind::AllowMemberRefOnExistential:
+  case FixKind::AllowNonClassTypeToConvertToAnyObject: {
     return recordFix(fix) ? SolutionKind::Error : SolutionKind::Solved;
   }
 
@@ -15647,6 +15934,22 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyFixConstraint(
     unsigned impact = 1;
     if (type1->isMarkerExistential() || type2->isMarkerExistential())
       ++impact;
+
+    // If generic arguments mismatch ends up being recorded on the result
+    // of the chain or a try expression it means that there is a contextual 
+    // conversion mismatch.
+    //
+    // For optional conversions the solver currently generates a disjunction
+    // with two choices - bind and optional-to-optional conversion which is
+    // anchored on the contextual expression. If we can get a fix recorded
+    // there that would result in a better diagnostic. It's only possible
+    // for optional-to-optional choice because it doesn't bind the
+    // variable immediately, so we need to downgrade direct fixes to prevent
+    // `bind` choice from considered better.
+    if (fix->directlyAt<OptionalEvaluationExpr>() ||
+        fix->directlyAt<AnyTryExpr>())
+      impact += 2;
+
     return recordFix(fix, impact) ? SolutionKind::Error : SolutionKind::Solved;
   }
 
@@ -15764,7 +16067,7 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyFixConstraint(
     auto dictionaryKeyTy = DependentMemberType::get(valueBaseTy, keyAssocTy);
 
     // Extract the array element type.
-    auto elemTy = type1->isArrayType();
+    auto elemTy = type1->getArrayElementType();
 
     ConstraintLocator *elemLoc = getConstraintLocator(AE->getElement(0));
     ConstraintKind kind = isDictionaryType(dictTy)
@@ -15874,7 +16177,6 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyFixConstraint(
   case FixKind::DefaultGenericArgument:
   case FixKind::AllowMutatingMemberOnRValueBase:
   case FixKind::AllowTupleSplatForSingleParameter:
-  case FixKind::AllowNonClassTypeToConvertToAnyObject:
   case FixKind::SpecifyClosureParameterType:
   case FixKind::SpecifyClosureReturnType:
   case FixKind::AddQualifierToAccessTopLevelName:
@@ -15891,6 +16193,8 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyFixConstraint(
   case FixKind::IgnoreOutOfPlaceThenStmt:
   case FixKind::IgnoreMissingEachKeyword:
   case FixKind::AllowInlineArrayLiteralCountMismatch:
+  case FixKind::TooManyDynamicMemberLookups:
+  case FixKind::IgnoreNonMetatypeDynamicType:
   case FixKind::IgnoreIsolatedConformance:
     llvm_unreachable("handled elsewhere");
   }
@@ -15903,6 +16207,8 @@ ConstraintSystem::addConstraintImpl(ConstraintKind kind, Type first,
                                     Type second,
                                     ConstraintLocatorBuilder locator,
                                     bool isFavored) {
+  ASSERT(!PreparingOverload);
+
   assert(first && "Missing first type");
   assert(second && "Missing second type");
 
@@ -16155,7 +16461,8 @@ ConstraintSystem::addKeyPathConstraint(
 void ConstraintSystem::addConstraint(Requirement req,
                                      ConstraintLocatorBuilder locator,
                                      bool isFavored,
-                                     bool prohibitNonisolatedConformance) {
+                                     bool prohibitNonisolatedConformance,
+                                     PreparedOverloadBuilder *preparedOverload) {
   bool conformsToAnyObject = false;
   std::optional<ConstraintKind> kind;
   switch (req.getKind()) {
@@ -16163,7 +16470,8 @@ void ConstraintSystem::addConstraint(Requirement req,
     auto type1 = req.getFirstType();
     auto type2 = req.getSecondType();
 
-    addConstraint(ConstraintKind::SameShape, type1, type2, locator);
+    addConstraint(ConstraintKind::SameShape, type1, type2, locator,
+                  /*isFavored=*/false, preparedOverload);
     return;
   }
 
@@ -16204,19 +16512,37 @@ void ConstraintSystem::addConstraint(Requirement req,
   auto firstType = req.getFirstType();
   if (kind) {
     addConstraint(*kind, req.getFirstType(), req.getSecondType(), locator,
-                  isFavored);
+                  isFavored, preparedOverload);
   }
 
   if (conformsToAnyObject) {
     auto anyObject = getASTContext().getAnyObjectConstraint();
-    addConstraint(ConstraintKind::ConformsTo, firstType, anyObject, locator);
+    addConstraint(ConstraintKind::ConformsTo, firstType, anyObject, locator,
+                  /*isFavored=*/false, preparedOverload);
   }
 }
 
 void ConstraintSystem::addConstraint(ConstraintKind kind, Type first,
                                      Type second,
                                      ConstraintLocatorBuilder locator,
-                                     bool isFavored) {
+                                     bool isFavored,
+                                     PreparedOverloadBuilder *preparedOverload) {
+  if (preparedOverload) {
+    ASSERT(PreparingOverload);
+    if (kind == ConstraintKind::Bind) {
+      ASSERT(!isFavored);
+      preparedOverload->addedBindConstraint(first, second);
+      return;
+    }
+    auto c = Constraint::create(*this, kind, first, second,
+                                getConstraintLocator(locator));
+    if (isFavored) c->setFavored();
+    preparedOverload->addedConstraint(c);
+    return;
+  }
+
+  ASSERT(!PreparingOverload);
+
   switch (addConstraintImpl(kind, first, second, locator, isFavored)) {
   case SolutionKind::Error:
     // Add a failing constraint, if needed.
@@ -16327,7 +16653,6 @@ void ConstraintSystem::addContextualConversionConstraint(
   case CTP_DictionaryValue:
   case CTP_CoerceOperand:
   case CTP_SubscriptAssignSource:
-  case CTP_ForEachStmt:
   case CTP_WrappedProperty:
   case CTP_ComposedPropertyWrapper:
   case CTP_ExprPattern:
@@ -16491,7 +16816,7 @@ ConstraintSystem::simplifyConstraint(const Constraint &constraint) {
         constraint.getFirstType(), constraint.getSecondType(),
         constraint.getThirdType(), std::nullopt, constraint.getLocator());
 
-  case ConstraintKind::BindOverload:
+  case ConstraintKind::BindOverload: {
     if (auto *fix = constraint.getFix()) {
       // TODO(diagnostics): Impact should be associated with a fix unless
       // it's a contextual problem, then only solver can decide what the impact
@@ -16502,10 +16827,27 @@ ConstraintSystem::simplifyConstraint(const Constraint &constraint) {
         return SolutionKind::Error;
     }
 
-    resolveOverload(constraint.getLocator(), constraint.getFirstType(),
-                    constraint.getOverloadChoice(),
-                    constraint.getDeclContext());
+    // FIXME: Transitional hack.
+    bool enablePreparedOverloads = getASTContext().TypeCheckerOpts.SolverEnablePreparedOverloads;
+
+    auto *preparedOverload = constraint.getPreparedOverload();
+    if (!preparedOverload) {
+      if (enablePreparedOverloads &&
+          constraint.getOverloadChoice().canBePrepared()) {
+        preparedOverload = prepareOverload(constraint.getOverloadChoice(),
+                                           constraint.getDeclContext(),
+                                           constraint.getLocator());
+        const_cast<Constraint &>(constraint).setPreparedOverload(preparedOverload);
+      }
+    }
+
+    resolveOverload(constraint.getOverloadChoice(),
+                    constraint.getDeclContext(),
+                    constraint.getLocator(),
+                    constraint.getFirstType(),
+                    preparedOverload);
     return SolutionKind::Solved;
+  }
 
   case ConstraintKind::SubclassOf:
     return simplifySubclassOfConstraint(constraint.getFirstType(),
diff --git a/lib/Sema/CSSolver.cpp b/lib/Sema/CSSolver.cpp
index 8e8b57cc7c982..44e80480e0cc1 100644
--- a/lib/Sema/CSSolver.cpp
+++ b/lib/Sema/CSSolver.cpp
@@ -22,6 +22,7 @@
 #include "swift/Basic/Defer.h"
 #include "swift/Sema/ConstraintGraph.h"
 #include "swift/Sema/ConstraintSystem.h"
+#include "swift/Sema/PreparedOverload.h"
 #include "swift/Sema/SolutionResult.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SetVector.h"
@@ -58,11 +59,17 @@ STATISTIC(LargestSolutionAttemptNumber, "# of the largest solution attempt");
 
 TypeVariableType *ConstraintSystem::createTypeVariable(
                                      ConstraintLocator *locator,
-                                     unsigned options) {
+                                     unsigned options,
+                                     PreparedOverloadBuilder *preparedOverload) {
   ++TotalNumTypeVariables;
   auto tv = TypeVariableType::getNew(getASTContext(), assignTypeVariableID(),
                                      locator, options);
-  addTypeVariable(tv);
+  if (preparedOverload) {
+    ASSERT(PreparingOverload);
+    preparedOverload->addedTypeVariable(tv);
+  } else {
+    addTypeVariable(tv);
+  }
   return tv;
 }
 
@@ -73,9 +80,7 @@ Solution ConstraintSystem::finalize() {
   Solution solution(*this, CurrentScore);
 
   // Update the best score we've seen so far.
-  auto &ctx = getASTContext();
-  assert(ctx.TypeCheckerOpts.DisableConstraintSolverPerformanceHacks ||
-         !solverState->BestScore || CurrentScore <= *solverState->BestScore);
+  assert(!solverState->BestScore || CurrentScore <= *solverState->BestScore);
 
   if (!solverState->BestScore || CurrentScore <= *solverState->BestScore) {
     solverState->BestScore = CurrentScore;
@@ -91,10 +96,6 @@ Solution ConstraintSystem::finalize() {
 
     case FreeTypeVariableBinding::Allow:
       break;
-
-    case FreeTypeVariableBinding::UnresolvedType:
-      assignFixedType(tv, ctx.TheUnresolvedType);
-      break;
     }
   }
 
@@ -983,7 +984,7 @@ void ConstraintSystem::Candidate::applySolutions(
 }
 
 void ConstraintSystem::shrink(Expr *expr) {
-  if (getASTContext().TypeCheckerOpts.SolverDisableShrink)
+  if (!performanceHacksEnabled())
     return;
 
   using DomainMap = llvm::SmallDenseMap<Expr *, ArrayRef<ValueDecl *>>;
@@ -1156,7 +1157,7 @@ void ConstraintSystem::shrink(Expr *expr) {
     ///
     /// \param collection The type of the collection container.
     ///
-    /// \returns Null type, ErrorType or UnresolvedType on failure,
+    /// \returns Null type or ErrorType on failure,
     /// properly constructed type otherwise.
     Type extractElementType(Type collection) {
       auto &ctx = CS.getASTContext();
@@ -1165,8 +1166,7 @@ void ConstraintSystem::shrink(Expr *expr) {
 
       auto base = collection.getPointer();
       auto isInvalidType = [](Type type) -> bool {
-        return type.isNull() || type->hasUnresolvedType() ||
-               type->hasError();
+        return type.isNull() || type->hasError();
       };
 
       // Array type.
@@ -1178,9 +1178,6 @@ void ConstraintSystem::shrink(Expr *expr) {
 
       // Map or Set or any other associated collection type.
       if (auto boundGeneric = dyn_cast<BoundGenericType>(base)) {
-        if (boundGeneric->hasUnresolvedType())
-          return boundGeneric;
-
         // Avoid handling InlineArray, building a tuple would be wrong, and
         // we want to eliminate shrink.
         if (boundGeneric->getDecl() == ctx.getInlineArrayDecl())
@@ -1289,9 +1286,7 @@ void ConstraintSystem::shrink(Expr *expr) {
         auto elementType = extractElementType(contextualType);
         // If we couldn't deduce element type for the collection, let's
         // not attempt to solve it.
-        if (!elementType ||
-            elementType->hasError() ||
-            elementType->hasUnresolvedType())
+        if (!elementType || elementType->hasError())
           return;
 
         contextualType = elementType;
@@ -1456,7 +1451,7 @@ ConstraintSystem::solve(SyntacticElementTarget &target,
     }
 
     case SolutionResult::Error:
-      maybeProduceFallbackDiagnostic(target);
+      maybeProduceFallbackDiagnostic(target.getLoc());
       return std::nullopt;
 
     case SolutionResult::TooComplex: {
@@ -1487,16 +1482,6 @@ ConstraintSystem::solve(SyntacticElementTarget &target,
         return std::nullopt;
       }
 
-      if (Options.contains(
-            ConstraintSystemFlags::AllowUnresolvedTypeVariables)) {
-        dumpSolutions(solution);
-        auto ambiguousSolutions = std::move(solution).takeAmbiguousSolutions();
-        std::vector<Solution> result(
-            std::make_move_iterator(ambiguousSolutions.begin()),
-            std::make_move_iterator(ambiguousSolutions.end()));
-        return std::move(result);
-      }
-
       LLVM_FALLTHROUGH;
 
     case SolutionResult::UndiagnosedError:
@@ -2017,6 +2002,29 @@ tryOptimizeGenericDisjunction(ConstraintSystem &cs, Constraint *disjunction,
       return nullptr;
   }
 
+  if (!cs.performanceHacksEnabled()) {
+    // Don't attempt this optimization if call has number literals.
+    // This is intended to narrowly fix situations like:
+    //
+    // func test<T: FloatingPoint>(_: T) { ... }
+    // func test<T: Numeric>(_: T) { ... }
+    //
+    // test(42)
+    //
+    // The call should use `<T: Numeric>` overload even though the
+    // `<T: FloatingPoint>` is a more specialized version because
+    // selecting `<T: Numeric>` doesn't introduce non-default literal
+    // types.
+    if (auto *argFnType = cs.getAppliedDisjunctionArgumentFunction(disjunction)) {
+      if (llvm::any_of(
+              argFnType->getParams(), [](const AnyFunctionType::Param &param) {
+                auto *typeVar = param.getPlainType()->getAs<TypeVariableType>();
+                return typeVar && typeVar->getImpl().isNumberLiteralType();
+              }))
+        return nullptr;
+    }
+  }
+
   llvm::SmallVector<Constraint *, 4> choices;
   for (auto *choice : constraints) {
     if (choices.size() > 2)
@@ -2293,6 +2301,8 @@ void DisjunctionChoiceProducer::partitionDisjunction(
   // end of the partitioning.
   SmallVector<unsigned, 4> favored;
   SmallVector<unsigned, 4> everythingElse;
+  // Disfavored choices are part of `everythingElse` but introduced at the end.
+  SmallVector<unsigned, 4> disfavored;
   SmallVector<unsigned, 4> simdOperators;
   SmallVector<unsigned, 4> disabled;
   SmallVector<unsigned, 4> unavailable;
@@ -2325,6 +2335,11 @@ void DisjunctionChoiceProducer::partitionDisjunction(
         everythingElse.push_back(index);
         return true;
       }
+
+      if (decl->getAttrs().hasAttribute<DisfavoredOverloadAttr>()) {
+        disfavored.push_back(index);
+        return true;
+      }
     }
 
     return false;
@@ -2368,6 +2383,9 @@ void DisjunctionChoiceProducer::partitionDisjunction(
     return true;
   });
 
+  // Introduce disfavored choices at the end.
+  everythingElse.append(disfavored);
+
   // Local function to create the next partition based on the options
   // passed in.
   PartitionAppendCallback appendPartition =
@@ -2387,7 +2405,7 @@ void DisjunctionChoiceProducer::partitionDisjunction(
   assert(Ordering.size() == Choices.size());
 }
 
-Constraint *ConstraintSystem::selectDisjunction() {
+Constraint *ConstraintSystem::selectDisjunctionWithHacks() {
   SmallVector<Constraint *, 4> disjunctions;
 
   collectDisjunctions(disjunctions);
diff --git a/lib/Sema/CSStep.cpp b/lib/Sema/CSStep.cpp
index 261d2c2e183e6..8b52fad07a6d5 100644
--- a/lib/Sema/CSStep.cpp
+++ b/lib/Sema/CSStep.cpp
@@ -272,7 +272,7 @@ StepResult ComponentStep::take(bool prevFailed) {
     }
   });
 
-  auto *disjunction = CS.selectDisjunction();
+  auto disjunction = CS.selectDisjunction();
   auto *conjunction = CS.selectConjunction();
 
   if (CS.isDebugMode()) {
@@ -280,13 +280,11 @@ StepResult ComponentStep::take(bool prevFailed) {
     CS.collectDisjunctions(disjunctions);
     std::vector<std::string> overloadDisjunctions;
     for (const auto &disjunction : disjunctions) {
-      PrintOptions PO;
-      PO.PrintTypesForDebugging = true;
-
       auto constraints = disjunction->getNestedConstraints();
       if (constraints[0]->getKind() == ConstraintKind::BindOverload)
         overloadDisjunctions.push_back(
-            constraints[0]->getFirstType()->getString(PO));
+            constraints[0]->getFirstType()->getString(
+                PrintOptions::forDebugging()));
     }
 
     if (!potentialBindings.empty() || !overloadDisjunctions.empty()) {
@@ -315,7 +313,8 @@ StepResult ComponentStep::take(bool prevFailed) {
     // Bindings usually happen first, but sometimes we want to prioritize a
     // disjunction or conjunction.
     if (bestBindings) {
-      if (disjunction && !bestBindings->favoredOverDisjunction(disjunction))
+      if (disjunction &&
+          !bestBindings->favoredOverDisjunction(disjunction->first))
         return StepKind::Disjunction;
 
       if (conjunction && !bestBindings->favoredOverConjunction(conjunction))
@@ -338,9 +337,9 @@ StepResult ComponentStep::take(bool prevFailed) {
       return suspend(
           std::make_unique<TypeVariableStep>(*bestBindings, Solutions));
     case StepKind::Disjunction: {
-      CS.retireConstraint(disjunction);
+      CS.retireConstraint(disjunction->first);
       return suspend(
-          std::make_unique<DisjunctionStep>(CS, disjunction, Solutions));
+          std::make_unique<DisjunctionStep>(CS, *disjunction, Solutions));
     }
     case StepKind::Conjunction: {
       CS.retireConstraint(conjunction);
@@ -356,14 +355,11 @@ StepResult ComponentStep::take(bool prevFailed) {
     // we can't solve this system unless we have free type variables
     // allowed in the solution.
     if (CS.isDebugMode()) {
-      PrintOptions PO;
-      PO.PrintTypesForDebugging = true;
-
       auto &log = getDebugLogger();
       log << "(failed due to free variables:";
       for (auto *typeVar : CS.getTypeVariables()) {
         if (!typeVar->getImpl().hasRepresentativeOrFixed()) {
-          log << " " << typeVar->getString(PO);
+          log << " " << typeVar->getString(PrintOptions::forDebugging());
         }
       }
       log << ")\n";
@@ -634,12 +630,30 @@ bool DisjunctionStep::shouldSkip(const DisjunctionChoice &choice) const {
   if (choice.isDisabled())
     return skip("disabled");
 
-  // Skip unavailable overloads (unless in diagnostic mode).
-  if (choice.isUnavailable() && !CS.shouldAttemptFixes())
-    return skip("unavailable");
+  if (!CS.shouldAttemptFixes()) {
+    // Skip unavailable overloads.
+    if (choice.isUnavailable())
+      return skip("unavailable");
+
+    // Since the disfavored overloads are always located at the end of
+    // the partition they could be skipped if there was at least one
+    // valid solution for this partition already, because the solution
+    // they produce would always be worse.
+    if (choice.isDisfavored() && LastSolvedChoice) {
+      bool canSkipDisfavored = true;
+      auto &lastScore = LastSolvedChoice->second;
+      for (unsigned i = 0, n = unsigned(SK_DisfavoredOverload) + 1; i != n;
+           ++i) {
+        if (lastScore.Data[i] > 0) {
+          canSkipDisfavored = false;
+          break;
+        }
+      }
 
-  if (ctx.TypeCheckerOpts.DisableConstraintSolverPerformanceHacks)
-    return false;
+      if (canSkipDisfavored)
+        return skip("disfavored");
+    }
+  }
 
   // If the solver already found a solution with a better overload choice that
   // can be unconditionally substituted by the current choice, skip the current
@@ -726,15 +740,10 @@ bool swift::isSIMDOperator(ValueDecl *value) {
 
 bool DisjunctionStep::shortCircuitDisjunctionAt(
     Constraint *currentChoice, Constraint *lastSuccessfulChoice) const {
-  auto &ctx = CS.getASTContext();
-
   // Anything without a fix is better than anything with a fix.
   if (currentChoice->getFix() && !lastSuccessfulChoice->getFix())
     return true;
 
-  if (ctx.TypeCheckerOpts.DisableConstraintSolverPerformanceHacks)
-    return false;
-
   if (auto restriction = currentChoice->getRestriction()) {
     // Non-optional conversions are better than optional-to-optional
     // conversions.
@@ -873,23 +882,24 @@ StepResult ConjunctionStep::resume(bool prevFailed) {
     if (Solutions.size() > 1)
       filterSolutions(Solutions, /*minimize=*/true);
 
-    // In diagnostic mode we need to stop a conjunction
-    // but consider it successful if there are:
+    // In diagnostic mode we need to stop a conjunction but consider it
+    // successful if there are:
     //
-    // - More than one solution for this element. Ambiguity
-    //   needs to get propagated back to the outer context
-    //   to be diagnosed.
-    // - A single solution that requires one or more fixes,
-    //   continuing would result in more errors associated
-    //   with the failed element.
+    // - More than one solution for this element. Ambiguity needs to get
+    //   propagated back to the outer context to be diagnosed.
+    // - A single solution that requires one or more fixes or holes, since
+    //   continuing would result in more errors associated with the failed
+    //   element, and we don't preserve scores across elements.
     if (CS.shouldAttemptFixes()) {
       if (Solutions.size() > 1)
         Producer.markExhausted();
 
       if (Solutions.size() == 1) {
         auto score = Solutions.front().getFixedScore();
-        if (score.Data[SK_Fix] > 0 && !CS.isForCodeCompletion())
-          Producer.markExhausted();
+        if (!CS.isForCodeCompletion()) {
+          if (score.Data[SK_Fix] > 0 || score.Data[SK_Hole] > 0)
+            Producer.markExhausted();
+        }
       }
     } else if (Solutions.size() != 1) {
       return failConjunction();
@@ -967,7 +977,15 @@ StepResult ConjunctionStep::resume(bool prevFailed) {
                 ++numHoles;
               }
             }
-            CS.increaseScore(SK_Hole, Conjunction->getLocator(), numHoles);
+            // Increase the score for each hole we bind. Avoid doing this for
+            // completion since it's entirely expected we'll end up with
+            // ambiguities in the body of a closure if we're completing e.g
+            // `someOverloadedFn(#^CC^#)`. As such we don't want to penalize the
+            // solution for unbound type variables outside of the body since
+            // that will prevent us from being able to eagerly prune e.g
+            // disfavored overloads in the outer scope.
+            if (!CS.isForCodeCompletion())
+              CS.increaseScore(SK_Hole, Conjunction->getLocator(), numHoles);
           }
 
           if (CS.worseThanBestSolution())
@@ -1031,7 +1049,7 @@ void ConjunctionStep::SolverSnapshot::replaySolution(const Solution &solution) {
 
   // If inference succeeded, we are done.
   auto score = solution.getFixedScore();
-  if (score.Data[SK_Fix] == 0)
+  if (score.Data[SK_Fix] == 0 && score.Data[SK_Hole] == 0)
     return;
 
   // If this conjunction represents a closure and inference
diff --git a/lib/Sema/CSStep.h b/lib/Sema/CSStep.h
index b35474b987847..a0b7a40cb03b9 100644
--- a/lib/Sema/CSStep.h
+++ b/lib/Sema/CSStep.h
@@ -407,15 +407,12 @@ class ComponentStep final : public SolverStep {
       auto &log = getDebugLogger();
       log << "Type variables in scope = "
           << "[";
-      auto typeVars = CS.getTypeVariables();
-      PrintOptions PO;
-      PO.PrintTypesForDebugging = true;
-      interleave(typeVars, [&](TypeVariableType *typeVar) {
-                   Type(typeVar).print(log, PO);
-                 },
-                 [&] {
-                   log << ", ";
-                 });
+      interleave(
+          CS.getTypeVariables(),
+          [&](TypeVariableType *typeVar) {
+            Type(typeVar).print(log, PrintOptions::forDebugging());
+          },
+          [&] { log << ", "; });
       log << "]" << '\n';
     }
 
@@ -553,9 +550,8 @@ class TypeVariableStep final : public BindingStep<TypeVarBindingProducer> {
   StepResult resume(bool prevFailed) override;
 
   void print(llvm::raw_ostream &Out) override {
-    PrintOptions PO;
-    PO.PrintTypesForDebugging = true;
-    Out << "TypeVariableStep for " << TypeVar->getString(PO) << '\n';
+    Out << "TypeVariableStep for ";
+    Out << TypeVar->getString(PrintOptions::forDebugging()) << '\n';
   }
 
 protected:
@@ -613,9 +609,17 @@ class DisjunctionStep final : public BindingStep<DisjunctionChoiceProducer> {
   std::optional<std::pair<Constraint *, Score>> LastSolvedChoice;
 
 public:
+  DisjunctionStep(
+      ConstraintSystem &cs,
+      std::pair<Constraint *, llvm::TinyPtrVector<Constraint *>> &disjunction,
+      SmallVectorImpl<Solution> &solutions)
+      : DisjunctionStep(cs, disjunction.first, disjunction.second, solutions) {}
+
   DisjunctionStep(ConstraintSystem &cs, Constraint *disjunction,
+                  llvm::TinyPtrVector<Constraint *> &favoredChoices,
                   SmallVectorImpl<Solution> &solutions)
-      : BindingStep(cs, {cs, disjunction}, solutions), Disjunction(disjunction) {
+      : BindingStep(cs, {cs, disjunction, favoredChoices}, solutions),
+        Disjunction(disjunction) {
     assert(Disjunction->getKind() == ConstraintKind::Disjunction);
     pruneOverloadSet(Disjunction);
     ++cs.solverState->NumDisjunctions;
@@ -684,6 +688,9 @@ class DisjunctionStep final : public BindingStep<DisjunctionChoiceProducer> {
   // chained together. If so, disable choices which differ
   // from currently selected representative.
   void pruneOverloadSet(Constraint *disjunction) {
+    if (!CS.performanceHacksEnabled())
+      return;
+
     auto *choice = disjunction->getNestedConstraints().front();
     if (choice->getKind() != ConstraintKind::BindOverload)
       return;
@@ -708,6 +715,9 @@ class DisjunctionStep final : public BindingStep<DisjunctionChoiceProducer> {
       // Disable all of the overload choices which are different from
       // the one which is currently picked for representative.
       for (auto *constraint : disjunction->getNestedConstraints()) {
+        if (constraint->isDisabled())
+          continue;
+
         auto choice = constraint->getOverloadChoice();
         if (!choice.isDecl() || choice.getDecl() == representative.getDecl())
           continue;
diff --git a/lib/Sema/CSSyntacticElement.cpp b/lib/Sema/CSSyntacticElement.cpp
index 36bdcd3c2f224..9ee3f0eb62702 100644
--- a/lib/Sema/CSSyntacticElement.cpp
+++ b/lib/Sema/CSSyntacticElement.cpp
@@ -309,10 +309,13 @@ static bool isViableElement(ASTNode element,
       // Skip if we're doing completion for a SingleValueStmtExpr, and have a
       // brace that doesn't involve a single expression, and doesn't have a
       // code completion token, as it won't contribute to the type of the
-      // SingleValueStmtExpr.
+      // SingleValueStmtExpr. We also need to skip if the body has a ReturnStmt,
+      // which isn't something that's currently allowed, but is necessary to
+      // correctly infer the contextual type without leaving it unbound.
       if (isForSingleValueStmtCompletion &&
           !SingleValueStmtExpr::hasResult(braceStmt) &&
-          !cs.containsIDEInspectionTarget(braceStmt)) {
+          !cs.containsIDEInspectionTarget(braceStmt) &&
+          !braceStmt->hasExplicitReturnStmt(cs.getASTContext())) {
         return false;
       }
     }
@@ -432,10 +435,14 @@ ElementInfo makeJoinElement(ConstraintSystem &cs, TypeJoinExpr *join,
                                     {LocatorPathElt::SyntacticElement(join)}));
 }
 
-struct SyntacticElementContext
-    : public llvm::PointerUnion<AbstractFunctionDecl *, AbstractClosureExpr *,
-                                SingleValueStmtExpr *, ExprPattern *, TapExpr *,
-                                CaptureListExpr *> {
+using SyntacticElementContextBase =
+    llvm::PointerUnion<AbstractFunctionDecl *, AbstractClosureExpr *,
+                       SingleValueStmtExpr *, ExprPattern *, TapExpr *,
+                       CaptureListExpr *>;
+
+struct SyntacticElementContext : public SyntacticElementContextBase {
+  using Base = SyntacticElementContextBase;
+
   // Inherit the constructors from PointerUnion.
   using PointerUnion::PointerUnion;
 
@@ -578,7 +585,7 @@ class SyntacticElementConstraintGenerator
     // constraint generation. The constraint system's DeclContext will be wrong
     // for solving, but CSGen should ensure that constraints carry the correct
     // DeclContext.
-    if (context.is<CaptureListExpr *>())
+    if (isa<CaptureListExpr *>(context))
       DCScope.emplace(cs.DC, context.getAsDeclContext());
   }
 
@@ -617,7 +624,7 @@ class SyntacticElementConstraintGenerator
   }
 
   void visitPattern(Pattern *pattern, ContextualTypeInfo contextInfo) {
-    if (context.is<ExprPattern *>()) {
+    if (isa<ExprPattern *>(context)) {
       // This is for an ExprPattern conjunction, go ahead and generate
       // constraints for the match expression.
       visitExprPattern(cast<ExprPattern>(pattern));
@@ -734,23 +741,6 @@ class SyntacticElementConstraintGenerator
                   LocatorPathElt::ContextualType(context.purpose)});
     cs.addConstraint(ConstraintKind::Equal, context.getType(), patternType,
                      loc);
-
-    // For any pattern variable that has a parent variable (i.e., another
-    // pattern variable with the same name in the same case), require that
-    // the types be equivalent.
-    pattern->forEachNode([&](Pattern *pattern) {
-      auto namedPattern = dyn_cast<NamedPattern>(pattern);
-      if (!namedPattern)
-        return;
-
-      auto var = namedPattern->getDecl();
-      if (auto parentVar = var->getParentVarDecl()) {
-        cs.addConstraint(
-            ConstraintKind::Equal, cs.getType(parentVar), cs.getType(var),
-            cs.getConstraintLocator(
-                locator, LocatorPathElt::PatternMatch(namedPattern)));
-      }
-    });
   }
 
   void visitPatternBinding(PatternBindingDecl *patternBinding,
@@ -841,12 +831,6 @@ class SyntacticElementConstraintGenerator
         ContextualPattern::forPatternBindingDecl(patternBinding, index);
     Type patternType = TypeChecker::typeCheckPattern(contextualPattern);
 
-    // Fail early if pattern couldn't be type-checked.
-    if (!patternType || patternType->hasError()) {
-      hadError = true;
-      return;
-    }
-
     auto target = getTargetForPattern(patternBinding, index, patternType);
     if (!target) {
       hadError = true;
@@ -1094,7 +1078,7 @@ class SyntacticElementConstraintGenerator
               .getElement();
 
       if (parent.isStmt(StmtKind::Switch)) {
-        auto *switchStmt = cast<SwitchStmt>(parent.get<Stmt *>());
+        auto *switchStmt = cast<SwitchStmt>(cast<Stmt *>(parent));
         contextualTy = cs.getType(switchStmt->getSubjectExpr());
       } else if (auto doCatch =
                      dyn_cast_or_null<DoCatchStmt>(parent.dyn_cast<Stmt *>())) {
@@ -1164,7 +1148,7 @@ class SyntacticElementConstraintGenerator
         } else if (auto stmt = node.dyn_cast<Stmt *>()) {
           visit(stmt);
         } else {
-          visitDecl(node.get<Decl *>());
+          visitDecl(cast<Decl *>(node));
         }
       }
       return;
@@ -1218,8 +1202,7 @@ class SyntacticElementConstraintGenerator
           !cs.containsIDEInspectionTarget(element)) {
         // To improve performance, skip type checking elements that can't
         // influence the code completion token.
-        if (element.is<Stmt *>() &&
-            !element.isStmt(StmtKind::Guard) &&
+        if (isa<Stmt *>(element) && !element.isStmt(StmtKind::Guard) &&
             !element.isStmt(StmtKind::Return) &&
             !element.isStmt(StmtKind::Then)) {
           // Statements can't influence the expresion that contains the code
@@ -1253,8 +1236,8 @@ class SyntacticElementConstraintGenerator
       bool isDiscarded = false;
       auto contextInfo = cs.getContextualTypeInfo(element);
 
-      if (element.is<Expr *>() &&
-          !ctx.LangOpts.Playground && !ctx.LangOpts.DebuggerSupport) {
+      if (isa<Expr *>(element) && !ctx.LangOpts.Playground &&
+          !ctx.LangOpts.DebuggerSupport) {
         isDiscarded = !contextInfo || contextInfo->purpose == CTP_Unused;
       }
 
@@ -1309,8 +1292,12 @@ class SyntacticElementConstraintGenerator
 
     // First check to make sure the ThenStmt is in a valid position.
     SmallVector<ThenStmt *, 4> validThenStmts;
-    if (auto SVE = context.getAsSingleValueStmtExpr())
+    if (auto SVE = context.getAsSingleValueStmtExpr()) {
       (void)SVE.get()->getThenStmts(validThenStmts);
+      if (SVE.get()->getStmtKind() == SingleValueStmtExpr::Kind::For) {
+        contextInfo = std::nullopt;
+      }
+    }
 
     if (!llvm::is_contained(validThenStmts, thenStmt)) {
       auto *thenLoc = cs.getConstraintLocator(thenStmt);
@@ -1398,7 +1385,7 @@ class SyntacticElementConstraintGenerator
       pattern->forEachVariable([&](VarDecl *var) { recordVar(var); });
     }
 
-    for (auto bodyVar : caseStmt->getCaseBodyVariablesOrEmptyArray()) {
+    for (auto bodyVar : caseStmt->getCaseBodyVariables()) {
       if (!bodyVar->hasName())
         continue;
 
@@ -1453,6 +1440,20 @@ class SyntacticElementConstraintGenerator
 };
 }
 
+namespace llvm {
+
+using ::SyntacticElementContext;
+
+/// `isa`, `dyn_cast`, `cast` for `SyntacticElementContext`.
+template <typename To>
+struct CastInfo<To, SyntacticElementContext>
+    : public CastInfo<To, SyntacticElementContext::Base> {};
+template <typename To>
+struct CastInfo<To, const SyntacticElementContext>
+    : public CastInfo<To, const SyntacticElementContext::Base> {};
+
+} // end namespace llvm
+
 bool ConstraintSystem::generateConstraints(TapExpr *tap) {
   SyntacticElementConstraintGenerator generator(
       *this, SyntacticElementContext::forTapExpr(tap),
@@ -1491,8 +1492,37 @@ bool ConstraintSystem::generateConstraints(SingleValueStmtExpr *E) {
   auto &ctx = getASTContext();
 
   auto *loc = getConstraintLocator(E);
-  Type resultTy = createTypeVariable(loc, /*options*/ 0);
-  setType(E, resultTy);
+  Type resultType = createTypeVariable(loc, /*options*/ 0);
+  setType(E, resultType);
+
+  if (E->getStmtKind() == SingleValueStmtExpr::Kind::For) {
+    auto *rrcProtocol =
+        ctx.getProtocol(KnownProtocolKind::RangeReplaceableCollection);
+    auto *sequenceProtocol = ctx.getProtocol(KnownProtocolKind::Sequence);
+
+    addConstraint(ConstraintKind::ConformsTo, resultType,
+                  rrcProtocol->getDeclaredInterfaceType(), loc);
+    Type elementTypeVar = createTypeVariable(loc, /*options*/ 0);
+    Type elementType = DependentMemberType::get(
+        resultType, sequenceProtocol->getAssociatedType(ctx.Id_Element));
+
+    addConstraint(ConstraintKind::Bind, elementTypeVar, elementType, loc);
+    addConstraint(ConstraintKind::Defaultable, resultType,
+                  ArraySliceType::get(elementTypeVar), loc);
+
+    auto *binding = E->getForExpressionPreamble()->ForAccumulatorBinding;
+
+    auto *initializer = binding->getInit(0);
+    auto target = SyntacticElementTarget::forInitialization(initializer, Type(),
+                                                            binding, 0, false);
+    setTargetFor({binding, 0}, target);
+
+    if (generateConstraints(target)) {
+      return true;
+    }
+
+    addConstraint(ConstraintKind::Bind, getType(initializer), resultType, loc);
+  }
 
   // Propagate the implied result kind from the if/switch expression itself
   // into the branches.
@@ -1516,21 +1546,24 @@ bool ConstraintSystem::generateConstraints(SingleValueStmtExpr *E) {
     auto *loc = getConstraintLocator(
         E, {LocatorPathElt::SingleValueStmtResult(idx), ctpElt});
 
-    ContextualTypeInfo info(resultTy, CTP_SingleValueStmtBranch, loc);
+    ContextualTypeInfo info(resultType, CTP_SingleValueStmtBranch, loc);
     setContextualInfo(result, info);
   }
 
   TypeJoinExpr *join = nullptr;
-  if (branches.empty()) {
-    // If we only have statement branches, the expression is typed as Void. This
-    // should only be the case for 'if' and 'switch' statements that must be
-    // expressions that have branches that all end in a throw, and we'll warn
-    // that we've inferred Void.
-    addConstraint(ConstraintKind::Bind, resultTy, ctx.getVoidType(), loc);
-  } else {
-    // Otherwise, we join the result types for each of the branches.
-    join = TypeJoinExpr::forBranchesOfSingleValueStmtExpr(
-        ctx, resultTy, E, AllocationArena::ConstraintSolver);
+
+  if (E->getStmtKind() != SingleValueStmtExpr::Kind::For) {
+    if (branches.empty()) {
+      // If we only have statement branches, the expression is typed as Void.
+      // This should only be the case for 'if' and 'switch' statements that must
+      // be expressions that have branches that all end in a throw, and we'll
+      // warn that we've inferred Void.
+      addConstraint(ConstraintKind::Bind, resultType, ctx.getVoidType(), loc);
+    } else {
+      // Otherwise, we join the result types for each of the branches.
+      join = TypeJoinExpr::forBranchesOfSingleValueStmtExpr(
+          ctx, resultType, E, AllocationArena::ConstraintSolver);
+    }
   }
 
   // If this is an implied return in a closure, we need to account for the fact
@@ -1571,11 +1604,11 @@ bool ConstraintSystem::generateConstraints(SingleValueStmtExpr *E) {
       if (auto *closureTy = getClosureTypeIfAvailable(CE)) {
         auto closureResultTy = closureTy->getResult();
         auto *bindToClosure = Constraint::create(
-            *this, ConstraintKind::Bind, resultTy, closureResultTy, loc);
+            *this, ConstraintKind::Bind, resultType, closureResultTy, loc);
         bindToClosure->setFavored();
 
-        auto *bindToVoid = Constraint::create(*this, ConstraintKind::Bind,
-                                              resultTy, ctx.getVoidType(), loc);
+        auto *bindToVoid = Constraint::create(
+            *this, ConstraintKind::Bind, resultType, ctx.getVoidType(), loc);
 
         addDisjunctionConstraint({bindToClosure, bindToVoid}, loc);
       }
@@ -1694,7 +1727,7 @@ ConstraintSystem::simplifySyntacticElementConstraint(
   } else if (auto *caseItem = element.dyn_cast<CaseLabelItem *>()) {
     generator.visitCaseItem(caseItem, contextInfo);
   } else {
-    generator.visit(element.get<Decl *>());
+    generator.visit(cast<Decl *>(element));
   }
 
   return generator.hadError ? SolutionKind::Error : SolutionKind::Solved;
@@ -1729,13 +1762,13 @@ class SyntacticElementSolutionApplication
 private:
   Type getContextualResultType() const {
     // Taps do not have a contextual result type.
-    if (context.is<TapExpr *>()) {
+    if (isa<TapExpr *>(context)) {
       return Type();
     }
 
     auto fn = context.getAsAnyFunctionRef();
 
-    if (context.is<SingleValueStmtExpr *>()) {
+    if (isa<SingleValueStmtExpr *>(context)) {
       // if/switch expressions can have `return` inside.
       fn = AnyFunctionRef::fromDeclContext(context.getAsDeclContext());
     }
@@ -1829,7 +1862,7 @@ class SyntacticElementSolutionApplication
     ifStmt->setThenStmt(castToStmt<BraceStmt>(visit(ifStmt->getThenStmt())));
 
     if (auto elseStmt = ifStmt->getElseStmt()) {
-      ifStmt->setElseStmt(visit(elseStmt).get<Stmt *>());
+      ifStmt->setElseStmt(cast<Stmt *>(visit(elseStmt)));
     }
 
     return ifStmt;
@@ -1842,7 +1875,7 @@ class SyntacticElementSolutionApplication
     else
       hadError = true;
 
-    auto *body = visit(guardStmt->getBody()).get<Stmt *>();
+    auto *body = cast<Stmt *>(visit(guardStmt->getBody()));
     guardStmt->setBody(cast<BraceStmt>(body));
     return guardStmt;
   }
@@ -1854,19 +1887,19 @@ class SyntacticElementSolutionApplication
     else
       hadError = true;
 
-    auto *body = visit(whileStmt->getBody()).get<Stmt *>();
+    auto *body = cast<Stmt *>(visit(whileStmt->getBody()));
     whileStmt->setBody(cast<BraceStmt>(body));
     return whileStmt;
   }
 
   virtual ASTNode visitDoStmt(DoStmt *doStmt) {
-    auto body = visit(doStmt->getBody()).get<Stmt *>();
+    auto *body = cast<Stmt *>(visit(doStmt->getBody()));
     doStmt->setBody(cast<BraceStmt>(body));
     return doStmt;
   }
 
   ASTNode visitRepeatWhileStmt(RepeatWhileStmt *repeatWhileStmt) {
-    auto body = visit(repeatWhileStmt->getBody()).get<Stmt *>();
+    auto *body = cast<Stmt *>(visit(repeatWhileStmt->getBody()));
     repeatWhileStmt->setBody(cast<BraceStmt>(body));
 
     // Rewrite the condition.
@@ -1939,7 +1972,7 @@ class SyntacticElementSolutionApplication
       }
     }
 
-    auto body = visit(forEachStmt->getBody()).get<Stmt *>();
+    auto *body = cast<Stmt *>(visit(forEachStmt->getBody()));
     forEachStmt->setBody(cast<BraceStmt>(body));
 
     // Check to see if the sequence expr is throwing (in async context),
@@ -1993,7 +2026,7 @@ class SyntacticElementSolutionApplication
   ASTNode visitDoCatchStmt(DoCatchStmt *doStmt) {
     // Translate the body.
     auto newBody = visit(doStmt->getBody());
-    doStmt->setBody(newBody.get<Stmt *>());
+    doStmt->setBody(cast<Stmt *>(newBody));
 
     // Visit the catch blocks.
     for (auto catchStmt : doStmt->getCatches())
@@ -2011,9 +2044,9 @@ class SyntacticElementSolutionApplication
       }
     }
 
-    bindSwitchCasePatternVars(context.getAsDeclContext(), caseStmt);
+    diagnoseCaseVarMutabilityMismatch(context.getAsDeclContext(), caseStmt);
 
-    for (auto *expected : caseStmt->getCaseBodyVariablesOrEmptyArray()) {
+    for (auto *expected : caseStmt->getCaseBodyVariables()) {
       assert(expected->hasName());
       auto prev = expected->getParentVarDecl();
       auto type = solution.getResolvedType(prev)->mapTypeOutOfContext();
@@ -2022,7 +2055,7 @@ class SyntacticElementSolutionApplication
   }
 
   void visitCaseStmtBody(CaseStmt *caseStmt) {
-    auto *newBody = visit(caseStmt->getBody()).get<Stmt *>();
+    auto *newBody = cast<Stmt *>(visit(caseStmt->getBody()));
     caseStmt->setBody(cast<BraceStmt>(newBody));
   }
 
@@ -2048,7 +2081,7 @@ class SyntacticElementSolutionApplication
     } else if (auto stmt = node.dyn_cast<Stmt *>()) {
       node = visit(stmt);
     } else {
-      visitDecl(node.get<Decl *>());
+      visitDecl(cast<Decl *>(node));
     }
     return node;
   }
@@ -2142,14 +2175,10 @@ class SyntacticElementSolutionApplication
       if (resultType->isVoid())
         return returnStmt;
 
-      // It's possible to infer e.g. `Void?` for cases where
-      // `return` doesn't have an expression. If contextual
-      // type is `Void` wrapped into N optional types, let's
-      // add an implicit `()` expression and let it be injected
-      // into optional required number of times.
-
-      assert(resultType->getOptionalObjectType() &&
-             resultType->lookThroughAllOptionalTypes()->isVoid());
+      // Constraint generation injects an implicit `()` expresion
+      // into return statements without one. This helps to match
+      // cases like `Void` and `Any` that could be wrapped into a
+      // number of optional types.
 
       auto target = *cs.getTargetFor(returnStmt);
       returnStmt->setResult(target.getAsExpr());
@@ -2228,7 +2257,9 @@ class SyntacticElementSolutionApplication
     // not the branch result type. This is necessary as there may be
     // an additional conversion required for the branch.
     auto target = solution.getTargetFor(thenStmt->getResult());
-    target->setExprConversionType(ty);
+    if (SVE.get()->getStmtKind() != SingleValueStmtExpr::Kind::For) {
+      target->setExprConversionType(ty);
+    }
 
     auto *resultExpr = thenStmt->getResult();
     if (auto newResultTarget = rewriter.rewriteTarget(*target))
@@ -2254,7 +2285,7 @@ class SyntacticElementSolutionApplication
   /// Apply the solution to the context and return updated statement.
   Stmt *apply() {
     auto body = visit(context.getStmt());
-    return body ? body.get<Stmt *>() : nullptr;
+    return body ? cast<Stmt *>(body) : nullptr;
   }
 };
 
@@ -2489,7 +2520,7 @@ class ResultBuilderRewriter : public SyntacticElementSolutionApplication {
 
       auto constraint = getUnsatisfiedAvailabilityConstraint(
           nominal, context.getAsDeclContext(), loc);
-      if (constraint && constraint->isPotentiallyAvailable()) {
+      if (constraint && !constraint->isUnavailable()) {
         auto &ctx = getASTContext();
         ctx.Diags.diagnose(loc,
                            diag::result_builder_missing_limited_availability,
@@ -2670,6 +2701,18 @@ bool ConstraintSystem::applySolutionToSingleValueStmt(
   if (!stmt || application.hadError)
     return true;
 
+  if (SVE->getStmtKind() == SingleValueStmtExpr::Kind::For) {
+    auto *binding = SVE->getForExpressionPreamble()->ForAccumulatorBinding;
+    auto target = getTargetFor({binding, 0}).value();
+
+    auto newTarget = rewriter.rewriteTarget(target);
+    if (!newTarget) {
+      return true;
+    }
+
+    binding->setInit(0, newTarget->getAsExpr());
+  }
+
   SVE->setStmt(stmt);
   return false;
 }
@@ -2701,7 +2744,7 @@ void ConjunctionElement::findReferencedVariables(
   //
   // Correct expressions wouldn't have any type variables in sequence but
   // they could appear due to circular references or other incorrect syntax.
-  if (element.is<Pattern *>()) {
+  if (isa<Pattern *>(element)) {
     if (auto parent =
             locator->getLastElementAs<LocatorPathElt::SyntacticElement>()) {
       if (auto *forEach = getAsStmt<ForEachStmt>(parent->getElement())) {
@@ -2728,8 +2771,8 @@ void ConjunctionElement::findReferencedVariables(
     }
   }
 
-  if (element.is<Decl *>() || element.is<StmtConditionElement *>() ||
-      element.is<Expr *>() || element.isPattern(PatternKind::Expr) ||
+  if (isa<Decl *>(element) || isa<StmtConditionElement *>(element) ||
+      isa<Expr *>(element) || element.isPattern(PatternKind::Expr) ||
       element.isStmt(StmtKind::Return)) {
     element.walk(refFinder);
   }
@@ -2744,11 +2787,13 @@ Type constraints::isPlaceholderVar(PatternBindingDecl *PB) {
     return Type();
 
   auto *pattern = PB->getPattern(0);
-  if (auto *typedPattern = dyn_cast<TypedPattern>(pattern)) {
-    auto type = typedPattern->getType();
-    if (type && type->hasPlaceholder())
-      return type;
-  }
+  auto *typedPattern = dyn_cast<TypedPattern>(pattern);
+  if (!typedPattern || !typedPattern->hasType())
+    return Type();
+
+  auto type = typedPattern->getType();
+  if (!type->hasPlaceholder())
+    return Type();
 
-  return Type();
+  return type;
 }
diff --git a/lib/Sema/CSTrail.cpp b/lib/Sema/CSTrail.cpp
index 7c7d6e61ee23e..61b1a77e1e0f8 100644
--- a/lib/Sema/CSTrail.cpp
+++ b/lib/Sema/CSTrail.cpp
@@ -577,8 +577,7 @@ void SolverTrail::Change::undo(ConstraintSystem &cs) const {
 void SolverTrail::Change::dump(llvm::raw_ostream &out,
                                ConstraintSystem &cs,
                                unsigned indent) const {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
+  PrintOptions PO = PrintOptions::forDebugging();
 
   out.indent(indent);
 
@@ -671,7 +670,7 @@ void SolverTrail::Change::dump(llvm::raw_ostream &out,
     }
     else {
       out << " to fixed type ";
-      parentOrFixed.get<TypeBase *>()->print(out, PO);
+      cast<TypeBase *>(parentOrFixed)->print(out, PO);
     }
     out << " with options 0x";
     out.write_hex(Options);
@@ -887,8 +886,7 @@ void SolverTrail::dumpActiveScopeChanges(llvm::raw_ostream &out,
   llvm::set_subtract(removedConstraints, intersects);
 
   // Print out Changes.
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
+  PrintOptions PO = PrintOptions::forDebugging();
   out.indent(indent);
   out << "(Changes:\n";
   if (!addedTypeVars.empty()) {
@@ -917,7 +915,7 @@ void SolverTrail::dumpActiveScopeChanges(llvm::raw_ostream &out,
         }
       }
 
-      if (typeVar->getImpl().ParentOrFixed.is<TypeBase *>())
+      if (isa<TypeBase *>(typeVar->getImpl().ParentOrFixed))
         assignments.push_back(typeVar);
     }
 
@@ -930,7 +928,7 @@ void SolverTrail::dumpActiveScopeChanges(llvm::raw_ostream &out,
       for (auto *typeVar : assignments) {
         out.indent(indent + 4);
         out << "> $T" << typeVar->getImpl().getID() << " := ";
-        typeVar->getImpl().ParentOrFixed.get<TypeBase *>()->print(out, PO);
+        cast<TypeBase *>(typeVar->getImpl().ParentOrFixed)->print(out, PO);
         out << '\n';
       }
       out.indent(indent + 2);
diff --git a/lib/Sema/CodeSynthesis.cpp b/lib/Sema/CodeSynthesis.cpp
index c0ca2d791b766..cdffea876a224 100644
--- a/lib/Sema/CodeSynthesis.cpp
+++ b/lib/Sema/CodeSynthesis.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -16,12 +16,12 @@
 
 #include "CodeSynthesis.h"
 
+#include "DerivedConformance/DerivedConformance.h"
 #include "TypeCheckDecl.h"
 #include "TypeCheckDistributed.h"
 #include "TypeCheckObjC.h"
 #include "TypeCheckType.h"
 #include "TypeChecker.h"
-#include "DerivedConformances.h"
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/ASTPrinter.h"
 #include "swift/AST/AvailabilityInference.h"
@@ -230,10 +230,12 @@ static ParamDecl *createMemberwiseInitParameter(DeclContext *DC,
     // memberwise initializer will be in terms of the backing storage
     // type.
     if (var->isPropertyMemberwiseInitializedWithWrappedType()) {
-      varInterfaceType = var->getPropertyWrapperInitValueInterfaceType();
+      if (auto initTy = var->getPropertyWrapperInitValueInterfaceType()) {
+        varInterfaceType = initTy;
 
-      auto initInfo = var->getPropertyWrapperInitializerInfo();
-      isAutoClosure = initInfo.getWrappedValuePlaceholder()->isAutoClosure();
+        auto initInfo = var->getPropertyWrapperInitializerInfo();
+        isAutoClosure = initInfo.getWrappedValuePlaceholder()->isAutoClosure();
+      }
     } else {
       varInterfaceType = backingPropertyType;
     }
@@ -403,15 +405,10 @@ static ConstructorDecl *createImplicitConstructor(NominalTypeDecl *decl,
                   decl->getDeclaredType(), existingIsolation, isolation)
                 .warnUntilSwiftVersion(6);
               if (previousVar) {
-                previousVar->diagnose(
-                    diag::property_requires_actor,
-                    previousVar->getDescriptiveKind(),
-                    previousVar->getName(), existingIsolation);
+                previousVar->diagnose(diag::property_requires_actor,
+                                      previousVar, existingIsolation);
               }
-              var->diagnose(
-                  diag::property_requires_actor,
-                  var->getDescriptiveKind(),
-                  var->getName(), isolation);
+              var->diagnose(diag::property_requires_actor, var, isolation);
               hasError = true;
               return false;
             }
@@ -593,7 +590,14 @@ configureInheritedDesignatedInitAttributes(ClassDecl *classDecl,
       // Inherit the @inlinable attribute.
       auto *clonedAttr = new (ctx) InlinableAttr(/*implicit=*/true);
       ctor->getAttrs().add(clonedAttr);
-
+    } else if (superclassCtor->getAttrs().hasAttribute<InlineAttr>() &&
+               superclassCtor->getAttrs().getAttribute<InlineAttr>()->getKind()
+               == InlineKind::Always) {
+      // Inherit the @inline(always) attribute.
+      auto *clonedAttr = new (ctx) InlineAttr(SourceLoc(), SourceRange(),
+                                              InlineKind::Always,
+                                              /*implicit=*/true);
+      ctor->getAttrs().add(clonedAttr);
     } else if (access == AccessLevel::Internal && !superclassCtor->isDynamic()){
       // Inherit the @usableFromInline attribute.
       auto *clonedAttr = new (ctx) UsableFromInlineAttr(/*implicit=*/true);
@@ -642,8 +646,8 @@ configureInheritedDesignatedInitAttributes(ClassDecl *classDecl,
   std::optional<ForeignAsyncConvention> asyncConvention;
   std::optional<ForeignErrorConvention> errorConvention;
   if (superclassCtor->isObjC() &&
-      !isRepresentableInObjC(ctor, ObjCReason::MemberOfObjCSubclass,
-                             asyncConvention, errorConvention))
+      !isRepresentableInLanguage(ctor, ObjCReason::MemberOfObjCSubclass,
+                                 asyncConvention, errorConvention))
     ctor->getAttrs().add(new (ctx) NonObjCAttr(/*isImplicit=*/true));
 }
 
@@ -1369,6 +1373,8 @@ evaluator::SideEffect
 ResolveImplicitMemberRequest::evaluate(Evaluator &evaluator,
                                        NominalTypeDecl *target,
                                        ImplicitMemberAction action) const {
+  ASSERT(!isa<ProtocolDecl>(target));
+
   // FIXME: This entire request is a layering violation made of smaller,
   // finickier layering violations. See rdar://56844567
 
@@ -1728,12 +1734,53 @@ bool swift::hasLetStoredPropertyWithInitialValue(NominalTypeDecl *nominal) {
   });
 }
 
+/// Determine whether a synthesized requirement for the given conformance
+/// should be explicitly marked as 'nonisolated'.
+static bool synthesizedRequirementIsNonIsolated(
+    const NormalProtocolConformance *conformance) {
+  // @preconcurrency suppresses this.
+  if (conformance->isPreconcurrency())
+    return false;
+
+  // Explicit global actor isolation suppresses this.
+  if (conformance->hasExplicitGlobalActorIsolation())
+    return false;
+
+  // Explicit nonisolated forces this.
+  if (conformance->getOptions()
+          .contains(ProtocolConformanceFlags::Nonisolated))
+    return true;
+
+  // When we are inferring conformance isolation, only add nonisolated if
+  // either
+  //   (1) the protocol inherits from SendableMetatype, or
+  //   (2) the conforming type is nonisolated.
+  ASTContext &ctx = conformance->getDeclContext()->getASTContext();
+  if (!ctx.LangOpts.hasFeature(Feature::InferIsolatedConformances))
+    return true;
+
+  // Check inheritance from SendableMetatype, which implies that the conformance
+  // will be nonisolated.
+  auto sendableMetatypeProto =
+      ctx.getProtocol(KnownProtocolKind::SendableMetatype);
+  if (sendableMetatypeProto &&
+      conformance->getProtocol()->inheritsFrom(sendableMetatypeProto))
+    return true;
+
+  auto nominalType = conformance->getType()->getAnyNominal();
+  if (!nominalType)
+    return true;
+
+  return !getActorIsolation(nominalType).isMainActor();
+}
+
 bool swift::addNonIsolatedToSynthesized(DerivedConformance &derived,
                                         ValueDecl *value) {
   if (auto *conformance = derived.Conformance) {
-    if (conformance && conformance->isPreconcurrency())
+    if (!synthesizedRequirementIsNonIsolated(conformance))
       return false;
   }
+
   return addNonIsolatedToSynthesized(derived.Nominal, value);
 }
 
@@ -1743,8 +1790,7 @@ bool swift::addNonIsolatedToSynthesized(NominalTypeDecl *nominal,
     return false;
 
   ASTContext &ctx = nominal->getASTContext();
-  value->getAttrs().add(
-      new (ctx) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true));
+  value->getAttrs().add(NonisolatedAttr::createImplicit(ctx));
   return true;
 }
 
diff --git a/lib/Sema/CodeSynthesisDistributedActor.cpp b/lib/Sema/CodeSynthesisDistributedActor.cpp
index 1bd4b6e545859..e4b5e5291499c 100644
--- a/lib/Sema/CodeSynthesisDistributedActor.cpp
+++ b/lib/Sema/CodeSynthesisDistributedActor.cpp
@@ -13,7 +13,7 @@
 #include "TypeCheckDistributed.h"
 
 #include "CodeSynthesis.h"
-#include "DerivedConformances.h"
+#include "DerivedConformance/DerivedConformance.h"
 #include "TypeChecker.h"
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/ASTPrinter.h"
@@ -110,8 +110,7 @@ static VarDecl *addImplicitDistributedActorIDProperty(
       nominal);
 
   // mark as nonisolated, allowing access to it from everywhere
-  propDecl->getAttrs().add(
-      new (C) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true));
+  propDecl->getAttrs().add(NonisolatedAttr::createImplicit(C));
   // mark as @_compilerInitialized, since we synthesize the initializing
   // assignment during SILGen.
   propDecl->getAttrs().add(
@@ -161,8 +160,7 @@ static VarDecl *addImplicitDistributedActorActorSystemProperty(
       nominal);
 
   // mark as nonisolated, allowing access to it from everywhere
-  propDecl->getAttrs().add(
-      new (C) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true));
+  propDecl->getAttrs().add(NonisolatedAttr::createImplicit(C));
 
   auto idProperty = nominal->getDistributedActorIDProperty();
   // If the id was not yet synthesized, we need to ensure that eventually
@@ -739,8 +737,11 @@ static FuncDecl *createSameSignatureDistributedThunkDecl(DeclContext *DC,
 
   thunk->setSynthesized(true);
   thunk->setDistributedThunk(true);
-  thunk->getAttrs().add(
-      new (C) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true));
+  thunk->getAttrs().add(NonisolatedAttr::createImplicit(C));
+  // TODO(distributed): It would be nicer to make distributed thunks nonisolated(nonsending) instead;
+  //                    this way we would not hop off the caller when calling system.remoteCall;
+  //                    it'd need new ABI and the remoteCall also to become nonisolated(nonsending)
+  thunk->getAttrs().add(new (C) ConcurrentAttr(/*IsImplicit=*/true));
 
   return thunk;
 }
@@ -819,10 +820,9 @@ addDistributedActorCodableConformance(
   }
 
   auto conformance = C.getNormalConformance(
-      actor->getDeclaredInterfaceType(), proto,
-      actor->getLoc(), /*dc=*/actor,
-      ProtocolConformanceState::Incomplete,
-      ProtocolConformanceOptions());
+      actor->getDeclaredInterfaceType(), proto, actor->getLoc(),
+      /*inheritedTypeRepr=*/nullptr, /*dc=*/actor,
+      ProtocolConformanceState::Incomplete, ProtocolConformanceOptions());
   conformance->setSourceKindAndImplyingConformance(
       ConformanceEntryKind::Synthesized, nullptr);
   actor->registerProtocolConformance(conformance, /*synthesized=*/true);
@@ -903,7 +903,7 @@ FuncDecl *GetDistributedThunkRequest::evaluate(Evaluator &evaluator,
       llvm_unreachable("unsupported storage kind");
     }
   } else {
-    distributedTarget = originator.get<AbstractFunctionDecl *>();
+    distributedTarget = cast<AbstractFunctionDecl *>(originator);
     if (!distributedTarget->isDistributed())
       return nullptr;
   }
@@ -1080,12 +1080,10 @@ GetDistributedActorAsActorConformanceRequest::evaluate(
   if (!ext)
     return nullptr;
 
-  auto genericParam = GenericTypeParamType::getType(/*depth=*/0, /*index=*/0,
-                                                    ctx);
-
   auto distributedActorAsActorConformance = ctx.getNormalConformance(
-      Type(genericParam), actorProto, SourceLoc(), ext,
-      ProtocolConformanceState::Incomplete, ProtocolConformanceOptions());
+      Type(ctx.TheSelfType), actorProto, SourceLoc(),
+      /*inheritedTypeRepr=*/nullptr, ext, ProtocolConformanceState::Incomplete,
+      ProtocolConformanceOptions());
   // NOTE: Normally we "register" a conformance, but here we don't
   // because we cannot (currently) register them in a protocol,
   // since they do not have conformance tables.
diff --git a/lib/Sema/CompletionContextFinder.cpp b/lib/Sema/CompletionContextFinder.cpp
index b63acd6d4ad98..07047cc6cf59e 100644
--- a/lib/Sema/CompletionContextFinder.cpp
+++ b/lib/Sema/CompletionContextFinder.cpp
@@ -17,45 +17,14 @@
 
 using namespace swift;
 using namespace constraints;
-using Fallback = CompletionContextFinder::Fallback;
 
 CompletionContextFinder::CompletionContextFinder(
-    SyntacticElementTarget target, DeclContext *DC)
-    : InitialExpr(target.getAsExpr()), InitialDC(DC) {
-  assert(DC);
+    SyntacticElementTarget target) {
   target.walk(*this);
 }
 
 ASTWalker::PreWalkResult<Expr *>
 CompletionContextFinder::walkToExprPre(Expr *E) {
-  if (auto *closure = dyn_cast<ClosureExpr>(E)) {
-    // NOTE: We're querying hasSingleExpressionBody before the single-expression
-    // body transform has happened, so this won't take e.g SingleValueStmtExprs
-    // into account.
-    Contexts.push_back({closure->hasSingleExpressionBody()
-                            ? ContextKind::SingleStmtClosure
-                            : ContextKind::MultiStmtClosure,
-                        closure});
-  }
-
-  if (isa<InterpolatedStringLiteralExpr>(E)) {
-    Contexts.push_back({ContextKind::StringInterpolation, E});
-  }
-
-  if (isa<ApplyExpr>(E) || isa<SequenceExpr>(E) ||
-      isa<SingleValueStmtExpr>(E)) {
-    Contexts.push_back({ContextKind::FallbackExpression, E});
-  }
-
-  if (auto *Error = dyn_cast<ErrorExpr>(E)) {
-    Contexts.push_back({ContextKind::ErrorExpression, E});
-    if (auto *OrigExpr = Error->getOriginalExpr()) {
-      OrigExpr->walk(*this);
-      if (hasCompletionExpr())
-        return Action::Stop();
-    }
-  }
-
   if (auto *CCE = dyn_cast<CodeCompletionExpr>(E)) {
     CompletionNode = CCE;
     return Action::Stop();
@@ -75,22 +44,7 @@ CompletionContextFinder::walkToExprPre(Expr *E) {
   return Action::Continue(E);
 }
 
-ASTWalker::PostWalkResult<Expr *>
-CompletionContextFinder::walkToExprPost(Expr *E) {
-  if (isa<ClosureExpr>(E) || isa<InterpolatedStringLiteralExpr>(E) ||
-      isa<ApplyExpr>(E) || isa<SequenceExpr>(E) || isa<ErrorExpr>(E) ||
-      isa<SingleValueStmtExpr>(E)) {
-    assert(Contexts.back().E == E);
-    Contexts.pop_back();
-  }
-  return Action::Continue(E);
-}
-
 ASTWalker::PreWalkAction CompletionContextFinder::walkToDeclPre(Decl *D) {
-  // Look through any decl if we're looking for any viable fallback expression.
-  if (ForFallback)
-    return Action::Continue();
-
   // Otherwise, follow the same rule as the ConstraintSystem, where only
   // nested PatternBindingDecls are solved as part of the system. Local decls
   // are handled by TypeCheckASTNodeAtLocRequest.
@@ -112,53 +66,6 @@ size_t CompletionContextFinder::getKeyPathCompletionComponentIndex() const {
   return ComponentIndex;
 }
 
-std::optional<Fallback>
-CompletionContextFinder::getFallbackCompletionExpr() const {
-  if (!hasCompletionExpr()) {
-    // Creating a fallback expression only makes sense if we are completing in
-    // an expression, not when we're completing in a key path.
-    return std::nullopt;
-  }
-
-  std::optional<Fallback> fallback;
-  bool separatePrecheck = false;
-  DeclContext *fallbackDC = InitialDC;
-
-  // Find the outermost fallback expression within the innermost error
-  // expression or multi-statement closure, keeping track of its decl context.
-  for (auto context : Contexts) {
-    switch (context.Kind) {
-    case ContextKind::StringInterpolation:
-      LLVM_FALLTHROUGH;
-    case ContextKind::FallbackExpression:
-      if (!fallback && context.E != InitialExpr)
-        fallback = Fallback{context.E, fallbackDC, separatePrecheck};
-      continue;
-
-    case ContextKind::SingleStmtClosure:
-      if (!fallback && context.E != InitialExpr)
-        fallback = Fallback{context.E, fallbackDC, separatePrecheck};
-      fallbackDC = cast<AbstractClosureExpr>(context.E);
-      continue;
-
-    case ContextKind::MultiStmtClosure:
-      fallbackDC = cast<AbstractClosureExpr>(context.E);
-      LLVM_FALLTHROUGH;
-    case ContextKind::ErrorExpression:;
-      fallback = std::nullopt;
-      separatePrecheck = true;
-      continue;
-    }
-  }
-
-  if (fallback)
-    return fallback;
-
-  if (getCompletionExpr() != InitialExpr)
-    return Fallback{getCompletionExpr(), fallbackDC, separatePrecheck};
-  return std::nullopt;
-}
-
 bool swift::containsIDEInspectionTarget(SourceRange range,
                                         const SourceManager &SourceMgr) {
   if (range.isInvalid())
diff --git a/lib/Sema/ConstantnessSemaDiagnostics.cpp b/lib/Sema/ConstantnessSemaDiagnostics.cpp
index ca2399d0c489e..9357f21070816 100644
--- a/lib/Sema/ConstantnessSemaDiagnostics.cpp
+++ b/lib/Sema/ConstantnessSemaDiagnostics.cpp
@@ -175,7 +175,8 @@ static Expr *checkConstantness(Expr *expr) {
       return expr;
 
     ApplyExpr *apply = cast<ApplyExpr>(expr);
-    ValueDecl *calledValue = apply->getCalledValue();
+    ValueDecl *calledValue =
+        apply->getCalledValue(/*skipFunctionConversions=*/true);
     if (!calledValue)
       return expr;
 
@@ -300,7 +301,8 @@ static void diagnoseConstantArgumentRequirementOfCall(const CallExpr *callExpr,
                                                       const ASTContext &ctx) {
   assert(callExpr && callExpr->getType() &&
          "callExpr should have a valid type");
-  ValueDecl *calledDecl = callExpr->getCalledValue();
+  ValueDecl *calledDecl =
+      callExpr->getCalledValue(/*skipFunctionConversions=*/true);
   if (!calledDecl || !isa<AbstractFunctionDecl>(calledDecl))
     return;
   AbstractFunctionDecl *callee = cast<AbstractFunctionDecl>(calledDecl);
diff --git a/lib/Sema/Constraint.cpp b/lib/Sema/Constraint.cpp
index 850f3fc378558..4d8268301156c 100644
--- a/lib/Sema/Constraint.cpp
+++ b/lib/Sema/Constraint.cpp
@@ -245,14 +245,15 @@ Constraint::Constraint(ConstraintKind kind, Type first, Type second,
   *getTrailingObjects<DeclContext *>() = useDC;
 }
 
-Constraint::Constraint(Type type, OverloadChoice choice, DeclContext *useDC,
+Constraint::Constraint(Type type, OverloadChoice choice,
+                       DeclContext *useDC,
                        ConstraintFix *fix, ConstraintLocator *locator,
                        SmallPtrSetImpl<TypeVariableType *> &typeVars)
     : Kind(ConstraintKind::BindOverload), NumTypeVariables(typeVars.size()),
       HasFix(fix != nullptr), HasDeclContext(true), HasRestriction(false),
       IsActive(false), IsDisabled(bool(fix)), IsDisabledForPerformance(false),
       RememberChoice(false), IsFavored(false), IsIsolated(false),
-      Overload{type}, Locator(locator) {
+      Overload{type, /*preparedOverload=*/nullptr}, Locator(locator) {
   std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
   if (fix)
     *getTrailingObjects<ConstraintFix *>() = fix;
@@ -337,8 +338,7 @@ ProtocolDecl *Constraint::getProtocol() const {
 void Constraint::print(llvm::raw_ostream &Out, SourceManager *sm,
                        unsigned indent, bool skipLocator) const {
   // Print all type variables as $T0 instead of _ here.
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
+  PrintOptions PO = PrintOptions::forDebugging();
 
   if (Kind == ConstraintKind::Disjunction ||
       Kind == ConstraintKind::Conjunction) {
@@ -394,7 +394,7 @@ void Constraint::print(llvm::raw_ostream &Out, SourceManager *sm,
     if (auto patternBindingElt =
             locator
                 ->getLastElementAs<LocatorPathElt::PatternBindingElement>()) {
-      auto *patternBinding = cast<PatternBindingDecl>(element.get<Decl *>());
+      auto *patternBinding = cast<PatternBindingDecl>(cast<Decl *>(element));
       Out << "pattern binding element @ ";
       Out << patternBindingElt->getIndex() << " : ";
       Out << '\n';
@@ -783,7 +783,7 @@ Constraint *Constraint::create(ConstraintSystem &cs, ConstraintKind kind,
   assert((kind != ConstraintKind::ConformsTo &&
           kind != ConstraintKind::NonisolatedConformsTo &&
           kind != ConstraintKind::TransitivelyConformsTo) ||
-         second->isExistentialType());
+         second->isAnyExistentialType());
 
   // Literal protocol conformances expect a protocol.
   assert((kind != ConstraintKind::LiteralConformsTo) ||
@@ -893,7 +893,7 @@ Constraint *Constraint::createValueWitness(
 }
 
 Constraint *Constraint::createBindOverload(ConstraintSystem &cs, Type type, 
-                                           OverloadChoice choice, 
+                                           OverloadChoice choice,
                                            DeclContext *useDC,
                                            ConstraintFix *fix,
                                            ConstraintLocator *locator) {
@@ -912,7 +912,8 @@ Constraint *Constraint::createBindOverload(ConstraintSystem &cs, Type type,
       typeVars.size(), fix ? 1 : 0, /*hasDeclContext=*/1,
       /*hasContextualTypeInfo=*/0, /*hasOverloadChoice=*/1);
   void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
-  return new (mem) Constraint(type, choice, useDC, fix, locator, typeVars);
+  return new (mem) Constraint(type, choice, useDC,
+                              fix, locator, typeVars);
 }
 
 Constraint *Constraint::createRestricted(ConstraintSystem &cs, 
diff --git a/lib/Sema/ConstraintGraph.cpp b/lib/Sema/ConstraintGraph.cpp
index d24f8a3f49b58..1c47c257ec983 100644
--- a/lib/Sema/ConstraintGraph.cpp
+++ b/lib/Sema/ConstraintGraph.cpp
@@ -254,36 +254,40 @@ void ConstraintGraphNode::truncateEquivalenceClass(unsigned prevSize) {
 void ConstraintGraphNode::addReferencedVar(TypeVariableType *typeVar) {
   bool inserted = References.insert(typeVar);
   if (!inserted) {
-    llvm::errs() << "$T" << TypeVar->getImpl().getID() << " already "
-                 << "references $T" << typeVar->getImpl().getID() << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "$T" << TypeVar->getImpl().getID() << " already "
+          << "references $T" << typeVar->getImpl().getID();
+    });
   }
 }
 
 void ConstraintGraphNode::addReferencedBy(TypeVariableType *typeVar) {
   bool inserted = ReferencedBy.insert(typeVar);
   if (!inserted) {
-    llvm::errs() << "$T" << TypeVar->getImpl().getID() << " already "
-                 << "referenced by $T" << typeVar->getImpl().getID() << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "$T" << TypeVar->getImpl().getID() << " already "
+          << "referenced by $T" << typeVar->getImpl().getID();
+    });
   }
 }
 
 void ConstraintGraphNode::removeReference(TypeVariableType *typeVar) {
   auto removed = References.remove(typeVar);
   if (!removed) {
-    llvm::errs() << "$T" << TypeVar->getImpl().getID() << " does not "
-                 << "reference $T" << typeVar->getImpl().getID() << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "$T" << TypeVar->getImpl().getID() << " does not "
+          << "reference $T" << typeVar->getImpl().getID();
+    });
   }
 }
 
 void ConstraintGraphNode::removeReferencedBy(TypeVariableType *typeVar) {
   auto removed = ReferencedBy.remove(typeVar);
   if (!removed) {
-    llvm::errs() << "$T" << TypeVar->getImpl().getID() << " not "
-                 << "referenced by $T" << typeVar->getImpl().getID() << "\n";
-    abort();
+    ABORT([&](auto &out) {
+      out << "$T" << TypeVar->getImpl().getID() << " not "
+          << "referenced by $T" << typeVar->getImpl().getID();
+    });
   }
 }
 
@@ -806,7 +810,7 @@ namespace {
 
       for (auto typeVar : typeVars) {
         auto &impl = typeVar->getImpl();
-        if (impl.getRepresentativeOrFixed().is<TypeBase *>()) {
+        if (isa<TypeBase *>(impl.getRepresentativeOrFixed())) {
           auto &node = cg[typeVar];
           for (auto otherTypeVar : node.getReferencedVars()) {
             unionSets(typeVar, otherTypeVar);
@@ -983,7 +987,7 @@ void ConstraintGraph::incrementConstraintsPerContractionCounter() {
 #pragma mark Debugging output
 
 void ConstraintGraphNode::print(llvm::raw_ostream &out, unsigned indent,
-                                PrintOptions PO) const {
+                                const PrintOptions &PO) const {
   out.indent(indent);
   Type(TypeVar).print(out, PO);
   out << ":\n";
@@ -1044,19 +1048,14 @@ void ConstraintGraphNode::print(llvm::raw_ostream &out, unsigned indent,
 }
 
 void ConstraintGraphNode::dump() const {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
-  print(llvm::dbgs(), 0, PO);
+  print(llvm::dbgs(), 0, PrintOptions::forDebugging());
 }
 
 void ConstraintGraph::print(ArrayRef<TypeVariableType *> typeVars,
                             llvm::raw_ostream &out) {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
-
   for (auto typeVar : typeVars) {
-    (*this)[typeVar].print(
-        out, (CS.solverState ? CS.solverState->getCurrentIndent() : 0) + 2, PO);
+    auto indent = (CS.solverState ? CS.solverState->getCurrentIndent() : 0) + 2;
+    (*this)[typeVar].print(out, indent, PrintOptions::forDebugging());
     out << "\n";
   }
 }
@@ -1073,8 +1072,7 @@ void ConstraintGraph::printConnectedComponents(
     ArrayRef<TypeVariableType *> typeVars,
     llvm::raw_ostream &out) {
   auto components = computeConnectedComponents(typeVars);
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
+
   for (const auto& component : components) {
     out.indent((CS.solverState ? CS.solverState->getCurrentIndent() : 0) + 2);
     out << component.solutionIndex << ": ";
@@ -1083,13 +1081,12 @@ void ConstraintGraph::printConnectedComponents(
     };
 
     // Print all of the type variables in this connected component.
-    interleave(component.typeVars,
-               [&](TypeVariableType *typeVar) {
-                 Type(typeVar).print(out, PO);
-               },
-               [&] {
-                 out << ' ';
-               });
+    interleave(
+        component.typeVars,
+        [&](TypeVariableType *typeVar) {
+          Type(typeVar).print(out, PrintOptions::forDebugging());
+        },
+        [&] { out << ' '; });
   }
 }
 
diff --git a/lib/Sema/ConstraintLocator.cpp b/lib/Sema/ConstraintLocator.cpp
index 5d567187eb6e4..2cf038ea98be0 100644
--- a/lib/Sema/ConstraintLocator.cpp
+++ b/lib/Sema/ConstraintLocator.cpp
@@ -129,8 +129,7 @@ unsigned LocatorPathElt::getNewSummaryFlags() const {
 }
 
 void LocatorPathElt::dump(raw_ostream &out) const {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
+  PrintOptions PO = PrintOptions::forDebugging();
 
   auto dumpReqKind = [&out](RequirementKind kind) {
     out << " (";
@@ -545,9 +544,17 @@ void LocatorPathElt::dump(raw_ostream &out) const {
 /// e.g. `foo[0]` or `\Foo.[0]`
 bool ConstraintLocator::isSubscriptMemberRef() const {
   auto anchor = getAnchor();
+  if (!anchor)
+    return false;
+
+  // Look through dynamic member lookup since for a subscript reference the
+  // dynamic member lookup is also a subscript reference.
   auto path = getPath();
+  using KPDynamicMemberElt = LocatorPathElt::KeyPathDynamicMember;
+  while (!path.empty() && path.back().is<KPDynamicMemberElt>())
+    path = path.drop_back();
 
-  if (!anchor || path.empty())
+  if (path.empty())
     return false;
 
   return path.back().getKind() == ConstraintLocator::SubscriptMember;
@@ -588,41 +595,41 @@ bool ConstraintLocator::isResultOfKeyPathDynamicMemberLookup() const {
   });
 }
 
-bool ConstraintLocator::isKeyPathSubscriptComponent() const {
-  auto *anchor = getAsExpr(getAnchor());
-  auto *KPE = dyn_cast_or_null<KeyPathExpr>(anchor);
+static bool hasKeyPathComponent(
+    const ConstraintLocator *loc,
+    llvm::function_ref<bool(KeyPathExpr::Component::Kind)> predicate) {
+  auto *KPE = getAsExpr<KeyPathExpr>(loc->getAnchor());
   if (!KPE)
     return false;
 
-  using ComponentKind = KeyPathExpr::Component::Kind;
-  return llvm::any_of(getPath(), [&](const LocatorPathElt &elt) {
+  return llvm::any_of(loc->getPath(), [&](const LocatorPathElt &elt) {
     auto keyPathElt = elt.getAs<LocatorPathElt::KeyPathComponent>();
     if (!keyPathElt)
       return false;
 
-    auto index = keyPathElt->getIndex();
-    auto &component = KPE->getComponents()[index];
-    return component.getKind() == ComponentKind::Subscript ||
-           component.getKind() == ComponentKind::UnresolvedSubscript;
+    auto &component = KPE->getComponents()[keyPathElt->getIndex()];
+    return predicate(component.getKind());
   });
 }
 
-bool ConstraintLocator::isKeyPathMemberComponent() const {
-  auto *anchor = getAsExpr(getAnchor());
-  auto *KPE = dyn_cast_or_null<KeyPathExpr>(anchor);
-  if (!KPE)
-    return false;
+bool ConstraintLocator::isKeyPathSubscriptComponent() const {
+  return hasKeyPathComponent(this, [](auto kind) {
+    return kind == KeyPathExpr::Component::Kind::Subscript ||
+           kind == KeyPathExpr::Component::Kind::UnresolvedSubscript;
+  });
+}
 
-  using ComponentKind = KeyPathExpr::Component::Kind;
-  return llvm::any_of(getPath(), [&](const LocatorPathElt &elt) {
-    auto keyPathElt = elt.getAs<LocatorPathElt::KeyPathComponent>();
-    if (!keyPathElt)
-      return false;
+bool ConstraintLocator::isKeyPathMemberComponent() const {
+  return hasKeyPathComponent(this, [](auto kind) {
+    return kind == KeyPathExpr::Component::Kind::Member ||
+           kind == KeyPathExpr::Component::Kind::UnresolvedMember;
+  });
+}
 
-    auto index = keyPathElt->getIndex();
-    auto &component = KPE->getComponents()[index];
-    return component.getKind() == ComponentKind::Member ||
-           component.getKind() == ComponentKind::UnresolvedMember;
+bool ConstraintLocator::isKeyPathApplyComponent() const {
+  return hasKeyPathComponent(this, [](auto kind) {
+    return kind == KeyPathExpr::Component::Kind::Apply ||
+           kind == KeyPathExpr::Component::Kind::UnresolvedApply;
   });
 }
 
@@ -803,9 +810,6 @@ void ConstraintLocator::dump(ConstraintSystem *CS) const {
 
 
 void ConstraintLocator::dump(SourceManager *sm, raw_ostream &out) const {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
-  
   out << "locator@" << (void*) this << " [";
 
   constraints::dumpAnchor(anchor, sm, out);
diff --git a/lib/Sema/ConstraintSystem.cpp b/lib/Sema/ConstraintSystem.cpp
index c0c3ffba9a8b6..c1787e3456353 100644
--- a/lib/Sema/ConstraintSystem.cpp
+++ b/lib/Sema/ConstraintSystem.cpp
@@ -20,6 +20,7 @@
 #include "OpenedExistentials.h"
 #include "TypeCheckAvailability.h"
 #include "TypeCheckConcurrency.h"
+#include "TypeCheckEmbedded.h"
 #include "TypeCheckMacros.h"
 #include "TypeCheckType.h"
 #include "TypeChecker.h"
@@ -38,6 +39,7 @@
 #include "swift/Sema/CSFix.h"
 #include "swift/Sema/ConstraintGraph.h"
 #include "swift/Sema/IDETypeChecking.h"
+#include "swift/Sema/PreparedOverload.h"
 #include "swift/Sema/SolutionResult.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallSet.h"
@@ -70,7 +72,7 @@ SourceRange ExpressionTimer::getAffectedRange() const {
     if (!anchor)
       anchor = locator->getAnchor();
   } else {
-    anchor = Anchor.get<Expr *>();
+    anchor = cast<Expr *>(Anchor);
   }
 
   return anchor.getSourceRange();
@@ -87,7 +89,7 @@ ExpressionTimer::~ExpressionTimer() {
     if (auto *E = Anchor.dyn_cast<Expr *>()) {
       E->getLoc().print(llvm::errs(), Context.SourceMgr);
     } else {
-      auto *locator = Anchor.get<ConstraintLocator *>();
+      auto *locator = cast<ConstraintLocator *>(Anchor);
       locator->dump(&Context.SourceMgr, llvm::errs());
     }
     llvm::errs() << "\n";
@@ -141,9 +143,18 @@ ConstraintSystem::~ConstraintSystem() {
 void ConstraintSystem::startExpressionTimer(ExpressionTimer::AnchorType anchor) {
   ASSERT(!Timer);
 
-  unsigned timeout = getASTContext().TypeCheckerOpts.ExpressionTimeoutThreshold;
-  if (timeout == 0)
-    return;
+  const auto &opts = getASTContext().TypeCheckerOpts;
+  unsigned timeout = opts.ExpressionTimeoutThreshold;
+
+  // If either the timeout is set, or we're asked to emit warnings,
+  // start the timer. Otherwise, don't start the timer, it's needless
+  // overhead.
+  if (timeout == 0) {
+    if (opts.WarnLongExpressionTypeChecking == 0)
+      return;
+
+    timeout = ExpressionTimer::NoLimit;
+  }
 
   Timer.emplace(anchor, *this, timeout);
 }
@@ -167,6 +178,8 @@ bool ConstraintSystem::hasFreeTypeVariables() {
 }
 
 void ConstraintSystem::addTypeVariable(TypeVariableType *typeVar) {
+  ASSERT(!PreparingOverload);
+
   TypeVariables.insert(typeVar);
 
   // Notify the constraint graph.
@@ -244,11 +257,28 @@ void ConstraintSystem::assignFixedType(TypeVariableType *typeVar, Type type,
 
       // If the protocol has a default type, check it.
       if (auto defaultType = TypeChecker::getDefaultType(literalProtocol, DC)) {
-        // Check whether the nominal types match. This makes sure that we
-        // properly handle Array vs. Array<T>.
-        if (defaultType->getAnyNominal() != type->getAnyNominal()) {
+        auto isDefaultType = [&literalProtocol, &defaultType](Type type) {
+          // Treat `std.string` as a default type just like we do
+          // Swift standard library `String`. This helps to disambiguate
+          // operator overloads that use `std.string` vs. a custom C++
+          // type that conforms to `ExpressibleByStringLiteral` as well.
+          //
+          // This doesn't clash with String because inference won't attempt
+          // C++ types unless we discover them from a constraint and the
+          // optimizer and old hacks always prefer the actual default type.
+          if (literalProtocol->getKnownProtocolKind() ==
+                  KnownProtocolKind::ExpressibleByStringLiteral &&
+              type->isCxxString()) {
+            return true;
+          }
+
+          // Check whether the nominal types match. This makes sure that we
+          // properly handle Array vs. Array<T>.
+          return defaultType->getAnyNominal() == type->getAnyNominal();
+        };
+
+        if (!isDefaultType(type))
           increaseScore(SK_NonDefaultLiteral, locator);
-        }
       }
 
       break;
@@ -295,6 +325,8 @@ void ConstraintSystem::removeConversionRestriction(
 }
 
 void ConstraintSystem::addFix(ConstraintFix *fix) {
+  ASSERT(!PreparingOverload);
+
   bool inserted = Fixes.insert(fix);
   ASSERT(inserted);
 
@@ -492,7 +524,7 @@ void ConstraintSystem::recordPotentialThrowSite(
 
   // do..catch statements without an explicit `throws` clause do infer
   // thrown types.
-  if (catchNode.is<DoCatchStmt *>()) {
+  if (isa<DoCatchStmt *>(catchNode)) {
     PotentialThrowSite site{kind, type, getConstraintLocator(locator)};
     recordPotentialThrowSite(catchNode, site);
     return;
@@ -500,7 +532,7 @@ void ConstraintSystem::recordPotentialThrowSite(
 
   // Closures without an explicit `throws` clause, and which syntactically
   // appear that they can throw, do infer thrown types.
-  auto closure = catchNode.get<ClosureExpr *>();
+  auto closure = cast<ClosureExpr *>(catchNode);
 
   // Check whether the closure syntactically throws. If not, there is no
   // need to record a throw site.
@@ -730,7 +762,9 @@ ConstraintLocator *ConstraintSystem::getCalleeLocator(
   }
 
   if (locator->isLastElement<LocatorPathElt::ArgumentAttribute>()) {
-    return getConstraintLocator(anchor, path.drop_back());
+    auto argLoc = getConstraintLocator(anchor, path.drop_back());
+    return getCalleeLocator(argLoc, lookThroughApply, getType, simplifyType,
+                            getOverloadFor);
   }
 
   // If we have a locator that starts with a key path component element, we
@@ -871,6 +905,73 @@ ConstraintLocator *ConstraintSystem::getOpenOpaqueLocator(
       { LocatorPathElt::OpenedOpaqueArchetype(opaqueDecl) }, 0);
 }
 
+void ConstraintSystem::setType(ASTNode node, Type type,
+                               PreparedOverloadBuilder *preparedOverload) {
+  ASSERT(PreparingOverload == !!preparedOverload);
+
+  ASSERT(!node.isNull() && "Cannot set type information on null node");
+  ASSERT(type && "Expected non-null type");
+
+  if (preparedOverload) {
+    preparedOverload->recordedNodeType(node, type);
+    return;
+  }
+
+  // Record the type.
+  Type &entry = NodeTypes[node];
+  Type oldType = entry;
+  entry = type;
+
+  if (oldType.getPointer() != type.getPointer()) {
+    // Record the fact that we assigned a type to this node.
+    if (solverState)
+      recordChange(SolverTrail::Change::RecordedNodeType(node, oldType));
+  }
+}
+
+void ConstraintSystem::restoreType(ASTNode node, Type oldType) {
+  ASSERT(!node.isNull() && "Cannot set type information on null node");
+
+  if (oldType) {
+    auto found = NodeTypes.find(node);
+    ASSERT(found != NodeTypes.end());
+    found->second = oldType;
+  } else {
+    bool erased = NodeTypes.erase(node);
+    ASSERT(erased);
+  }
+}
+
+void ConstraintSystem::setType(const KeyPathExpr *KP, unsigned I, Type T) {
+  ASSERT(KP && "Expected non-null key path parameter!");
+  ASSERT(T && "Expected non-null type!");
+
+  Type &entry = KeyPathComponentTypes[{KP, I}];
+  Type oldType = entry;
+  entry = T;
+
+  if (oldType.getPointer() != T.getPointer()) {
+    if (solverState) {
+      recordChange(
+        SolverTrail::Change::RecordedKeyPathComponentType(
+          KP, I, oldType));
+    }
+  }
+}
+
+void ConstraintSystem::restoreType(const KeyPathExpr *KP, unsigned I, Type T) {
+  ASSERT(KP && "Expected non-null key path parameter!");
+
+  if (T) {
+    auto found = KeyPathComponentTypes.find({KP, I});
+    ASSERT(found != KeyPathComponentTypes.end());
+    found->second = T;
+  } else {
+    bool erased = KeyPathComponentTypes.erase({KP, I});
+    ASSERT(erased);
+  }
+}
+
 std::pair<Type, ExistentialArchetypeType *>
 ConstraintSystem::openAnyExistentialType(Type type,
                                          ConstraintLocator *locator) {
@@ -886,7 +987,14 @@ ConstraintSystem::openAnyExistentialType(Type type,
 }
 
 void ConstraintSystem::recordOpenedExistentialType(
-    ConstraintLocator *locator, ExistentialArchetypeType *opened) {
+    ConstraintLocator *locator,
+    ExistentialArchetypeType *opened,
+    PreparedOverloadBuilder *preparedOverload) {
+  if (preparedOverload) {
+    preparedOverload->openedExistentialType(opened);
+    return;
+  }
+
   bool inserted = OpenedExistentialTypes.insert({locator, opened}).second;
   ASSERT(inserted);
 
@@ -1062,6 +1170,7 @@ std::optional<Type> ConstraintSystem::isSetType(Type type) {
 
 Type ConstraintSystem::getFixedTypeRecursive(Type type, TypeMatchOptions &flags,
                                              bool wantRValue) {
+  ASSERT(!PreparingOverload);
 
   if (wantRValue)
     type = type->getRValueType();
@@ -1414,12 +1523,10 @@ FunctionType::ExtInfo ClosureEffectsRequest::evaluate(
   bool async = expr->getAsyncLoc().isValid();
   bool sendable = expr->getAttrs().hasAttribute<SendableAttr>();
 
-  // `@execution(...)` attribute is only valid on asynchronous function types.
-  if (expr->getAttrs().hasAttribute<ExecutionAttr>()) {
-    async = true;
-  }
-
   if (throws || async) {
+    if (expr->getThrowsLoc().isValid() && !expr->getExplicitThrownTypeRepr())
+      diagnoseUntypedThrowsInEmbedded(expr, expr->getThrowsLoc());
+
     return ASTExtInfoBuilder()
       .withThrows(throws, /*FIXME:*/Type())
       .withAsync(async)
@@ -1692,7 +1799,7 @@ struct TypeSimplifier {
             auto elementAssocTy = arrayProto->getAssociatedTypeMembers()[0];
 
             if (proto == arrayProto && assocType == elementAssocTy) {
-              return lookupBaseType->isArrayType();
+              return lookupBaseType->getInlineArrayElementType();
             }
           }
 
@@ -1709,7 +1816,7 @@ struct TypeSimplifier {
           return memberTy;
         }
 
-        auto result = conformance.getTypeWitness(lookupBaseType, assocType);
+        auto result = conformance.getTypeWitness(assocType);
         if (result && !result->hasError())
           return result;
       }
@@ -1729,6 +1836,8 @@ Type ConstraintSystem::simplifyTypeImpl(Type type,
 }
 
 Type ConstraintSystem::simplifyType(Type type) {
+  ASSERT(!PreparingOverload);
+
   if (!type->hasTypeVariable())
     return type;
 
@@ -1752,13 +1861,85 @@ void Solution::recordSingleArgMatchingChoice(ConstraintLocator *locator) {
        MatchCallArgumentResult::forArity(1)});
 }
 
-Type Solution::simplifyType(Type type, bool wantInterfaceType) const {
+static GenericTypeParamType *
+getGenericParamForHoleTypeVar(TypeVariableType *tv, const Solution &S) {
+  auto getGenericParam = [](TypeVariableType *tv) -> GenericTypeParamType * {
+    auto *gp = tv->getImpl().getGenericParameter();
+    if (!gp)
+      return nullptr;
+    // Note we only consider generic parameters with underlying decls since for
+    // diagnostics we want something we can print, and for completion we want
+    // something we can extract a GenericEnvironment to produce an archetype.
+    return gp->getDecl() ? gp : nullptr;
+  };
+
+  if (auto *gp = getGenericParam(tv))
+    return gp;
+
+  // Sometimes we run into cases where the originator of a hole isn't for
+  // the generic parameter, instead it's for a member of its equivalence
+  // class. Handle this by looking through all the bindings to see if we have
+  // the same hole bound to a generic parameter type variable.
+  for (auto &binding : S.typeBindings) {
+    if (auto *hole = binding.second->getAs<PlaceholderType>()) {
+      if (hole->getOriginator().dyn_cast<TypeVariableType *>() == tv) {
+        if (auto *gp = getGenericParam(binding.first))
+          return gp;
+      }
+    }
+  }
+  return nullptr;
+}
+
+static Type replacePlaceholderType(PlaceholderType *placeholder,
+                                   const Solution &S, bool forCompletion) {
+  auto &ctx = S.getConstraintSystem().getASTContext();
+  auto origTy = [&]() -> Type {
+    auto orig = placeholder->getOriginator();
+    if (auto *tv = orig.dyn_cast<TypeVariableType *>())
+      return tv;
+    if (auto *dmt = orig.dyn_cast<DependentMemberType *>())
+      return dmt;
+    return Type();
+  }();
+  if (!origTy)
+    return ErrorType::get(ctx);
+
+  // Try replace the type variable with its original generic parameter type.
+  auto replacement = origTy.transformRec([&](Type ty) -> std::optional<Type> {
+    auto *tv = dyn_cast<TypeVariableType>(ty.getPointer());
+    if (!tv)
+      return std::nullopt;
+
+    auto *gp = getGenericParamForHoleTypeVar(tv, S);
+    if (!gp)
+      return std::nullopt;
+
+    return Type(gp);
+  });
+  // For completion, we want to produce an archetype instead of an ErrorType
+  // for a top-level generic parameter.
+  // FIXME: This is pretty weird, we're producing a contextual type outside of
+  // the context it exists in. We ought to see if we can make the completion
+  // logic work with ErrorTypes instead.
+  if (forCompletion) {
+    if (auto *GP = replacement->getAs<GenericTypeParamType>())
+      return GP->getDecl()->getInnermostDeclContext()->mapTypeIntoContext(GP);
+  }
+  // Return an ErrorType with the replacement as the original type. Note that
+  // if we failed to replace a type variable with a generic parameter,
+  // `ErrorType::get` will fold it away.
+  return ErrorType::get(replacement);
+}
+
+Type Solution::simplifyType(Type type, bool wantInterfaceType,
+                            bool forCompletion) const {
   // If we've been asked for an interface type, start by mapping any archetypes
   // out of context.
   if (wantInterfaceType)
     type = type->mapTypeOutOfContext();
 
-  if (!(type->hasTypeVariable() || type->hasPlaceholder()))
+  if (!type->hasTypeVariableOrPlaceholder())
     return type;
 
   // Map type variables to fixed types from bindings.
@@ -1776,150 +1957,38 @@ Type Solution::simplifyType(Type type, bool wantInterfaceType) const {
       });
   ASSERT(!(wantInterfaceType && resolvedType->hasPrimaryArchetype()));
 
-  // Placeholders shouldn't be reachable through a solution, they are only
-  // useful to determine what went wrong exactly.
-  if (resolvedType->hasPlaceholder()) {
-    return resolvedType.transformRec([&](Type type) -> std::optional<Type> {
-      if (type->isPlaceholder())
-        return Type(cs.getASTContext().TheUnresolvedType);
-      return std::nullopt;
-    });
-  }
-
-  return resolvedType;
-}
+  // We may have type variables and placeholders left over. These are solver
+  // allocated so cannot escape this function. Turn them into ErrorType.
+  // - Type variables may still be present from unresolved pack expansions where
+  //   e.g the count type is a hole, so the pattern may never become a
+  //   concrete type.
+  // - Placeholders may be present for any holes.
+  if (resolvedType->hasTypeVariableOrPlaceholder()) {
+    auto &ctx = cs.getASTContext();
+    resolvedType =
+        resolvedType.transformRec([&](Type type) -> std::optional<Type> {
+          if (!type->hasTypeVariableOrPlaceholder())
+            return type;
 
-Type Solution::simplifyTypeForCodeCompletion(Type Ty) const {
-  auto &CS = getConstraintSystem();
+          auto *typePtr = type.getPointer();
 
-  // First, instantiate all type variables that we know, but don't replace
-  // placeholders by unresolved types.
-  Ty = CS.simplifyTypeImpl(Ty, [this](TypeVariableType *typeVar) -> Type {
-    return getFixedType(typeVar);
-  });
+          if (auto *placeholder = dyn_cast<PlaceholderType>(typePtr))
+            return replacePlaceholderType(placeholder, *this, forCompletion);
 
-  // Next, replace all placeholders by type variables. We know that all type
-  // variables now in the type originate from placeholders.
-  Ty = Ty.transformRec([](Type type) -> std::optional<Type> {
-    if (auto *placeholder = type->getAs<PlaceholderType>()) {
-      if (auto *typeVar =
-              placeholder->getOriginator().dyn_cast<TypeVariableType *>()) {
-        return Type(typeVar);
-      }
-    }
+          if (isa<TypeVariableType>(typePtr))
+            return ErrorType::get(ctx);
 
-    return std::nullopt;
-  });
-
-  // Replace all type variables (which must come from placeholders) by their
-  // generic parameters. Because we call into simplifyTypeImpl
-  Ty = CS.simplifyTypeImpl(Ty, [&CS, this](TypeVariableType *typeVar) -> Type {
-    // Code completion depends on generic parameter type being represented in
-    // terms of `ArchetypeType` since it's easy to extract protocol requirements
-    // from it.
-    auto getTypeVarAsArchetype = [](TypeVariableType *typeVar) -> Type {
-      if (auto *GP = typeVar->getImpl().getGenericParameter()) {
-        if (auto *GPD = GP->getDecl()) {
-          return GPD->getInnermostDeclContext()->mapTypeIntoContext(GP);
-        }
-      }
-      return Type();
-    };
-
-    if (auto archetype = getTypeVarAsArchetype(typeVar)) {
-      return archetype;
-    }
-
-    // Sometimes the type variable itself doesn't have have an originator that
-    // can be replaced by an archetype but one of its equivalent type variable
-    // does.
-    // Search thorough all equivalent type variables, looking for one that can
-    // be replaced by a generic parameter.
-    std::vector<std::pair<TypeVariableType *, Type>> bindings(
-        typeBindings.begin(), typeBindings.end());
-    // Make sure we iterate the bindings in a deterministic order.
-    llvm::sort(bindings, [](const std::pair<TypeVariableType *, Type> &lhs,
-                            const std::pair<TypeVariableType *, Type> &rhs) {
-      return lhs.first->getID() < rhs.first->getID();
-    });
-    for (auto binding : bindings) {
-      if (auto placeholder = binding.second->getAs<PlaceholderType>()) {
-        if (placeholder->getOriginator().dyn_cast<TypeVariableType *>() ==
-            typeVar) {
-          if (auto archetype = getTypeVarAsArchetype(binding.first)) {
-            return archetype;
-          }
-        }
-      }
-    }
-
-    // When applying the logic below to get contextual types inside result
-    // builders, the code completion type variable is connected by a one-way
-    // constraint to a type variable in the buildBlock call, but that is not the
-    // type variable that represents the argument type. We need to find the type
-    // variable representing the argument to retrieve protocol requirements from
-    // it. Look for a ArgumentConversion constraint that allows us to retrieve
-    // the argument type var.
-    auto &cg = CS.getConstraintGraph();
-
-    // FIXME: The type variable is not going to be part of the constraint graph
-    // at this point unless it was created at the outermost decision level;
-    // otherwise it has already been rolled back! Work around this by creating
-    // an empty node if one doesn't exist.
-    cg.addTypeVariable(typeVar);
-
-    for (auto argConstraint : cg[typeVar].getConstraints()) {
-      if (argConstraint->getKind() == ConstraintKind::ArgumentConversion &&
-          argConstraint->getFirstType()->getRValueType()->isEqual(typeVar)) {
-        if (auto argTV =
-                argConstraint->getSecondType()->getAs<TypeVariableType>()) {
-          if (auto archetype = getTypeVarAsArchetype(argTV)) {
-            return archetype;
-          }
-        }
-      }
-    }
-
-    return typeVar;
-  });
-
-  // Logic to determine the contextual type inside buildBlock result builders:
-  //
-  // When completing inside a result builder, the result builder
-  //   @ViewBuilder var body: some View {
-  //     Text("Foo")
-  //     #^COMPLETE^#
-  //   }
-  // gets rewritten to
-  //   @ViewBuilder var body: some View {
-  //     let $__builder2: Text
-  //     let $__builder0 = Text("Foo")
-  //     let $__builder1 = #^COMPLETE^#
-  //     $__builder2 = ViewBuilder.buildBlock($__builder0, $__builder1)
-  //     return $__builder2
-  //   }
-  // Inside the constraint system
-  //     let $__builder1 = #^COMPLETE^#
-  // gets type checked without context, so we can't know the contextual type for
-  // the code completion token. But we know that $__builder1 (and thus the type
-  // of #^COMPLETE^#) is used as the second argument to ViewBuilder.buildBlock,
-  // so we can extract the contextual type from that call. To do this, figure
-  // out the type variable that is used for $__builder1 in the buildBlock call.
-  // This type variable is connected to the type variable of $__builder1's
-  // definition by a one-way constraint.
-  if (auto TV = Ty->getAs<TypeVariableType>()) {
-    for (auto constraint : CS.getConstraintGraph()[TV].getConstraints()) {
-      if (constraint->getKind() == ConstraintKind::OneWayEqual &&
-          constraint->getSecondType()->isEqual(TV)) {
-        return simplifyTypeForCodeCompletion(constraint->getFirstType());
-      }
-    }
+          return std::nullopt;
+        });
   }
 
-  // Remove any remaining type variables and placeholders
-  Ty = simplifyType(Ty);
+  ASSERT(!resolvedType->getRecursiveProperties().isSolverAllocated());
+  return resolvedType;
+}
 
-  return Ty->getRValueType();
+Type Solution::simplifyTypeForCodeCompletion(Type Ty) const {
+  return simplifyType(Ty, /*wantInterfaceType*/ false, /*forCompletion*/ true)
+      ->getRValueType();
 }
 
 template <typename T>
@@ -1987,7 +2056,7 @@ DeclName OverloadChoice::getName() const {
     case OverloadChoiceKind::MaterializePack:
     case OverloadChoiceKind::TupleIndex:
     case OverloadChoiceKind::ExtractFunctionIsolation:
-      llvm_unreachable("no name!");
+      return DeclName();
   }
 
   llvm_unreachable("Unhandled OverloadChoiceKind in switch.");
@@ -3364,6 +3433,41 @@ bool ConstraintSystem::diagnoseAmbiguity(ArrayRef<Solution> solutions) {
   return false;
 }
 
+void OpenGenericTypeRequirements::operator()(GenericTypeDecl *decl,
+                                             TypeSubstitutionFn subst) const {
+  auto *outerDC = decl->getDeclContext();
+  auto sig = decl->getGenericSignature();
+
+  // In principle we shouldn't need to open the generic parameters here, we
+  // could just open the requirements using the substituted arguments directly,
+  // but that doesn't allow us to correctly handle requirement fix coalescing
+  // in `isFixedRequirement`. So instead we open the generic parameters and
+  // then bind the resulting type variables to the substituted args.
+  SmallVector<OpenedType, 4> replacements;
+  cs.openGenericParameters(outerDC, sig, replacements, locator,
+                           preparedOverload);
+
+  // FIXME: Get rid of fixmeAllowDuplicates. This is the same issue as in
+  // `openUnboundGenericType`; both `applyUnboundGenericArguments` &
+  // `replaceInferableTypesWithTypeVars` can open multiple different generic
+  // types with the same locator. For the former we ought to plumb through the
+  // TypeRepr and use that to distinguish the locator. For the latter we ought
+  // to try migrating clients off it, pushing the opening up to type resolution.
+  cs.recordOpenedTypes(locator, replacements, preparedOverload,
+                       /*fixmeAllowDuplicates*/ true);
+
+  for (auto [gp, typeVar] : replacements) {
+    cs.addConstraint(ConstraintKind::Bind, typeVar, subst(gp), locator,
+                     /*isFavored=*/false, preparedOverload);
+  }
+
+  auto openType = [&](Type ty) -> Type {
+    return cs.openType(ty, replacements, locator, preparedOverload);
+  };
+  cs.openGenericRequirements(outerDC, sig, /*skipProtocolSelf*/ false, locator,
+                             openType, preparedOverload);
+}
+
 ConstraintLocator *
 constraints::simplifyLocator(ConstraintSystem &cs, ConstraintLocator *locator,
                              SourceRange &range) {
@@ -3531,7 +3635,7 @@ void constraints::simplifyLocator(ASTNode &anchor,
         path = path.slice(1);
         continue;
       }
-      if (anchor.is<Pattern *>()) {
+      if (isa<Pattern *>(anchor)) {
         path = path.slice(1);
         continue;
       }
@@ -3544,7 +3648,7 @@ void constraints::simplifyLocator(ASTNode &anchor,
         continue;
       }
 
-      if (anchor.is<Pattern *>()) {
+      if (isa<Pattern *>(anchor)) {
         path = path.slice(1);
         continue;
       }
@@ -3764,7 +3868,7 @@ void constraints::simplifyLocator(ASTNode &anchor,
 
     case ConstraintLocator::PatternBindingElement: {
       auto pattern = path[0].castTo<LocatorPathElt::PatternBindingElement>();
-      auto *patternBinding = cast<PatternBindingDecl>(anchor.get<Decl *>());
+      auto *patternBinding = cast<PatternBindingDecl>(cast<Decl *>(anchor));
       anchor = patternBinding->getInit(pattern.getIndex());
       // If this pattern is uninitialized, let's use it as anchor.
       if (!anchor)
@@ -3774,7 +3878,7 @@ void constraints::simplifyLocator(ASTNode &anchor,
     }
 
     case ConstraintLocator::NamedPatternDecl: {
-      auto pattern = cast<NamedPattern>(anchor.get<Pattern *>());
+      auto pattern = cast<NamedPattern>(cast<Pattern *>(anchor));
       anchor = pattern->getDecl();
       path = path.slice(1);
       break;
@@ -3858,6 +3962,13 @@ bool constraints::hasAppliedSelf(ConstraintSystem &cs,
   });
 }
 
+bool constraints::hasAppliedSelf(const Solution &S,
+                                 const OverloadChoice &choice) {
+  return hasAppliedSelf(choice, [&](Type type) -> Type {
+    return S.simplifyType(type);
+  });
+}
+
 bool constraints::hasAppliedSelf(const OverloadChoice &choice,
                                  llvm::function_ref<Type(Type)> getFixedType) {
   auto *decl = choice.getDeclOrNull();
@@ -3886,7 +3997,7 @@ Type constraints::isRawRepresentable(ConstraintSystem &cs, Type type) {
   if (conformance.isInvalid())
     return Type();
 
-  return conformance.getTypeWitnessByName(type, cs.getASTContext().Id_RawValue);
+  return conformance.getTypeWitnessByName(cs.getASTContext().Id_RawValue);
 }
 
 void ConstraintSystem::generateOverloadConstraints(
@@ -4135,7 +4246,7 @@ Solution::getFunctionArgApplyInfo(ConstraintLocator *locator) const {
     // If callee couldn't be resolved due to expression
     // issues e.g. it's a reference to an invalid member
     // let's just return here.
-    if (simplifyType(rawFnType)->is<UnresolvedType>())
+    if (simplifyType(rawFnType)->is<ErrorType>())
       return std::nullopt;
 
     // A tuple construction is spelled in the AST as a function call, but
@@ -4173,8 +4284,7 @@ Solution::getFunctionArgApplyInfo(ConstraintLocator *locator) const {
     fnInterfaceType = callee->getInterfaceType();
 
     // Strip off the curried self parameter if necessary.
-    if (hasAppliedSelf(
-            *choice, [this](Type type) -> Type { return simplifyType(type); }))
+    if (hasAppliedSelf(*this, *choice))
       fnInterfaceType = fnInterfaceType->castTo<AnyFunctionType>()->getResult();
 
 #ifndef NDEBUG
@@ -4201,12 +4311,6 @@ Solution::getFunctionArgApplyInfo(ConstraintLocator *locator) const {
                                    fnInterfaceType, fnType, callee);
 }
 
-bool constraints::isKnownKeyPathType(Type type) {
-  return type->isKeyPath() || type->isWritableKeyPath() ||
-         type->isReferenceWritableKeyPath() || type->isPartialKeyPath() ||
-         type->isAnyKeyPath();
-}
-
 bool constraints::isTypeErasedKeyPathType(Type type) {
   assert(type);
 
@@ -4232,15 +4336,9 @@ Type constraints::getConcreteReplacementForProtocolSelfType(ValueDecl *member) {
   if (!DC->getSelfProtocolDecl())
     return Type();
 
-  GenericSignature signature;
-  if (auto *genericContext = member->getAsGenericContext()) {
-    signature = genericContext->getGenericSignature();
-  } else {
-    signature = DC->getGenericSignatureOfContext();
-  }
-
+  auto sig = member->getInnermostDeclContext()->getGenericSignatureOfContext();
   auto selfTy = DC->getSelfInterfaceType();
-  return signature->getConcreteType(selfTy);
+  return sig->getConcreteType(selfTy);
 }
 
 static bool isOperator(Expr *expr, StringRef expectedName) {
@@ -4407,11 +4505,9 @@ ConstraintSystem::isConversionEphemeral(ConversionRestrictionKind conversion,
 
       // Check what access strategy is used for a read-write access. It must be
       // direct-to-storage in order for the conversion to be non-ephemeral.
-      auto access = asd->getAccessStrategy(
+      return asd->isAccessedViaPhysicalStorage(
           AccessSemantics::Ordinary, AccessKind::ReadWrite,
-          DC->getParentModule(), DC->getResilienceExpansion(),
-          /*useOldABI=*/false);
-      return access.getKind() == AccessStrategy::Storage;
+          DC->getParentModule(), DC->getResilienceExpansion());
     };
 
     SourceRange range;
@@ -4714,6 +4810,21 @@ void ConstraintSystem::diagnoseFailureFor(SyntacticElementTarget target) {
     return;
   }
 
+  if (auto *wrappedVar = target.getAsUninitializedWrappedVar()) {
+    auto *outerWrapper = wrappedVar->getOutermostAttachedPropertyWrapper();
+    Type propertyType = wrappedVar->getInterfaceType();
+    Type wrapperType = outerWrapper->getType();
+
+    // Emit the property wrapper fallback diagnostic
+    wrappedVar->diagnose(diag::property_wrapper_incompatible_property,
+                         propertyType, wrapperType);
+    if (auto nominal = wrapperType->getAnyNominal()) {
+      nominal->diagnose(diag::property_wrapper_declared_here,
+                        nominal->getName());
+    }
+    return;
+  }
+
   if (auto expr = target.getAsExpr()) {
     if (auto *assignment = dyn_cast<AssignExpr>(expr)) {
       if (isa<DiscardAssignmentExpr>(assignment->getDest()))
@@ -4731,44 +4842,30 @@ void ConstraintSystem::diagnoseFailureFor(SyntacticElementTarget target) {
         .highlight(closure->getSourceRange());
       return;
     }
-
-    // If no one could find a problem with this expression or constraint system,
-    // then it must be well-formed... but is ambiguous.  Handle this by
-    // diagnostic various cases that come up.
-    DE.diagnose(expr->getLoc(), diag::type_of_expression_is_ambiguous)
-        .highlight(expr->getSourceRange());
-  } else if (auto *wrappedVar = target.getAsUninitializedWrappedVar()) {
-    auto *outerWrapper = wrappedVar->getOutermostAttachedPropertyWrapper();
-    Type propertyType = wrappedVar->getInterfaceType();
-    Type wrapperType = outerWrapper->getType();
-
-    // Emit the property wrapper fallback diagnostic
-    wrappedVar->diagnose(diag::property_wrapper_incompatible_property,
-                         propertyType, wrapperType);
-    if (auto nominal = wrapperType->getAnyNominal()) {
-      nominal->diagnose(diag::property_wrapper_declared_here,
-                        nominal->getName());
-    }
-  } else if (target.getAsUninitializedVar()) {
-    DE.diagnose(target.getLoc(), diag::failed_to_produce_diagnostic);
-  } else if (target.isForEachPreamble()) {
-    DE.diagnose(target.getLoc(), diag::failed_to_produce_diagnostic);
-  } else {
-    // Emit a poor fallback message.
-    DE.diagnose(target.getAsFunction()->getLoc(),
-                diag::failed_to_produce_diagnostic);
   }
+
+  // Emit a poor fallback message.
+  auto diag = DE.diagnose(target.getLoc(), diag::failed_to_produce_diagnostic);
+  if (auto *expr = target.getAsExpr())
+    diag.highlight(expr->getSourceRange());
 }
 
 bool ConstraintSystem::isDeclUnavailable(const Decl *D,
                                          ConstraintLocator *locator) const {
+  auto found = UnavailableDecls.find(std::make_pair(D, locator));
+  if (found != UnavailableDecls.end())
+    return found->second;
+
   SourceLoc loc;
   if (locator) {
     if (auto anchor = locator->getAnchor())
       loc = getLoc(anchor);
   }
 
-  return getUnsatisfiedAvailabilityConstraint(D, DC, loc).has_value();
+  auto result = getUnsatisfiedAvailabilityConstraint(D, DC, loc).has_value();
+  const_cast<ConstraintSystem *>(this)->UnavailableDecls.insert(
+      std::make_pair(std::make_pair(D, locator), result));
+  return result;
 }
 
 bool ConstraintSystem::isConformanceUnavailable(ProtocolConformanceRef conformance,
@@ -4787,8 +4884,7 @@ bool ConstraintSystem::isConformanceUnavailable(ProtocolConformanceRef conforman
 
 /// If we aren't certain that we've emitted a diagnostic, emit a fallback
 /// diagnostic.
-void ConstraintSystem::maybeProduceFallbackDiagnostic(
-    SyntacticElementTarget target) const {
+void ConstraintSystem::maybeProduceFallbackDiagnostic(SourceLoc loc) const {
   if (Options.contains(ConstraintSystemFlags::SuppressDiagnostics))
     return;
 
@@ -4800,7 +4896,7 @@ void ConstraintSystem::maybeProduceFallbackDiagnostic(
       (diagnosticTransaction && diagnosticTransaction->hasErrors()))
     return;
 
-  ctx.Diags.diagnose(target.getLoc(), diag::failed_to_produce_diagnostic);
+  ctx.Diags.diagnose(loc, diag::failed_to_produce_diagnostic);
 }
 
 SourceLoc constraints::getLoc(ASTNode anchor) {
@@ -4819,7 +4915,7 @@ SourceLoc constraints::getLoc(ASTNode anchor) {
   } else if (auto *C = anchor.dyn_cast<StmtConditionElement *>()) {
     return C->getStartLoc();
   } else {
-    auto *I = anchor.get<CaseLabelItem *>();
+    auto *I = cast<CaseLabelItem *>(anchor);
     return I->getStartLoc();
   }
 }
@@ -4966,11 +5062,7 @@ bool ConstraintSystem::isReadOnlyKeyPathComponent(
   // If the setter is unavailable, then the keypath ought to be read-only
   // in this context.
   if (auto setter = storage->getOpaqueAccessor(AccessorKind::Set)) {
-    // FIXME: [availability] Fully unavailable setters should cause the key path
-    // to be readonly too.
-    auto constraint =
-        getUnsatisfiedAvailabilityConstraint(setter, DC, referenceLoc);
-    if (constraint && constraint->isPotentiallyAvailable())
+    if (getUnsatisfiedAvailabilityConstraint(setter, DC, referenceLoc))
       return true;
   }
 
@@ -5175,7 +5267,7 @@ ConstraintSystem::inferKeyPathLiteralCapability(KeyPathExpr *keyPath) {
       case ActorIsolation::Erased:
         llvm_unreachable("storage cannot have opaque isolation");
 
-      // A reference to an actor isolated state makes key path non-Sendable.
+      // A reference to an actor-isolated state makes key path non-Sendable.
       case ActorIsolation::ActorInstance:
       case ActorIsolation::GlobalActor:
         isSendable = false;
diff --git a/lib/Sema/DerivedConformance/DerivedConformance.cpp b/lib/Sema/DerivedConformance/DerivedConformance.cpp
new file mode 100644
index 0000000000000..216c3f6f18ad3
--- /dev/null
+++ b/lib/Sema/DerivedConformance/DerivedConformance.cpp
@@ -0,0 +1,1008 @@
+//===--- DerivedConformance.cpp ---------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "DerivedConformance.h"
+#include "TypeCheckConcurrency.h"
+#include "TypeChecker.h"
+#include "swift/AST/ASTPrinter.h"
+#include "swift/AST/ConformanceLookup.h"
+#include "swift/AST/Decl.h"
+#include "swift/AST/Expr.h"
+#include "swift/AST/ParameterList.h"
+#include "swift/AST/Pattern.h"
+#include "swift/AST/ProtocolConformance.h"
+#include "swift/AST/SourceFile.h"
+#include "swift/AST/Stmt.h"
+#include "swift/AST/Types.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/ClangImporter/ClangModule.h"
+
+using namespace swift;
+
+enum NonconformingMemberKind { AssociatedValue, StoredProperty };
+
+DerivedConformance::DerivedConformance(
+    const NormalProtocolConformance *conformance, NominalTypeDecl *nominal,
+    ProtocolDecl *protocol)
+    : Context(nominal->getASTContext()), Conformance(conformance),
+      Nominal(nominal), Protocol(protocol) {
+  auto *DC = Conformance->getDeclContext();
+  ConformanceDecl = DC->getInnermostDeclarationDeclContext();
+  assert(ConformanceDecl);
+  assert(DC->getSelfNominalTypeDecl() == nominal);
+}
+
+DeclContext *DerivedConformance::getConformanceContext() const {
+  return Conformance->getDeclContext();
+}
+
+ModuleDecl *DerivedConformance::getParentModule() const {
+  return getConformanceContext()->getParentModule();
+}
+
+void DerivedConformance::addMembersToConformanceContext(
+    ArrayRef<Decl *> children) {
+  auto IDC = cast<IterableDeclContext>(ConformanceDecl);
+  for (auto child : children)
+    IDC->addMember(child);
+}
+
+void DerivedConformance::addMemberToConformanceContext(
+    Decl *member, Decl *hint) {
+  auto IDC = cast<IterableDeclContext>(ConformanceDecl);
+  IDC->addMember(member, hint, /*insertAtHead=*/false);
+}
+
+void DerivedConformance::addMemberToConformanceContext(
+    Decl *member, bool insertAtHead) {
+  auto IDC = cast<IterableDeclContext>(ConformanceDecl);
+  IDC->addMember(member, /*hint=*/nullptr, insertAtHead);
+}
+
+Type DerivedConformance::getProtocolType() const {
+  return Protocol->getDeclaredInterfaceType();
+}
+
+bool DerivedConformance::derivesProtocolConformance(
+      NormalProtocolConformance *Conformance) {
+  auto *Protocol = Conformance->getProtocol();
+
+  const auto derivableKind = Protocol->getKnownDerivableProtocolKind();
+  if (!derivableKind)
+    return false;
+
+  // When the necessary requirements are met, the conformance to OptionSet
+  // is serendipitously derived via memberwise initializer synthesis.
+  if (*derivableKind == KnownDerivableProtocolKind::OptionSet) {
+    return false;
+  }
+
+  auto *DC = Conformance->getDeclContext();
+  auto *Nominal = DC->getSelfNominalTypeDecl();
+
+  if (*derivableKind == KnownDerivableProtocolKind::Hashable) {
+    // We can always complete a partial Hashable implementation, and we can
+    // synthesize a full Hashable implementation for structs and enums with
+    // Hashable components.
+    return canDeriveHashable(Nominal);
+  }
+
+  if (*derivableKind == KnownDerivableProtocolKind::Actor)
+    return canDeriveActor(DC, Nominal);
+
+  if (*derivableKind == KnownDerivableProtocolKind::Identifiable)
+    return canDeriveIdentifiable(Nominal, DC);
+  if (*derivableKind == KnownDerivableProtocolKind::DistributedActor)
+    return canDeriveDistributedActor(Nominal, DC);
+  if (*derivableKind == KnownDerivableProtocolKind::DistributedActorSystem)
+    return canDeriveDistributedActorSystem(Nominal, DC);
+
+  if (*derivableKind == KnownDerivableProtocolKind::AdditiveArithmetic)
+    return canDeriveAdditiveArithmetic(Nominal, DC);
+
+  // Eagerly return true here. Actual synthesis conditions are checked in
+  // `DerivedConformance::deriveDifferentiable`: they are complicated and depend
+  // on the requirement being derived.
+  if (*derivableKind == KnownDerivableProtocolKind::Differentiable)
+    return true;
+
+  if (*derivableKind == KnownDerivableProtocolKind::Encodable) {
+    return canDeriveEncodable(Nominal);
+  }
+
+  if (*derivableKind == KnownDerivableProtocolKind::Decodable) {
+    return canDeriveDecodable(Nominal);
+  }
+
+  if (auto *enumDecl = dyn_cast<EnumDecl>(Nominal)) {
+    switch (*derivableKind) {
+        // The presence of a raw type is an explicit declaration that
+        // the compiler should derive a RawRepresentable conformance.
+      case KnownDerivableProtocolKind::RawRepresentable:
+        return canDeriveRawRepresentable(DC, Nominal);
+
+        // Enums without associated values can implicitly derive Equatable
+        // conformance.
+      case KnownDerivableProtocolKind::Equatable:
+        return canDeriveEquatable(DC, Nominal);
+      
+      case KnownDerivableProtocolKind::Comparable:
+        return !enumDecl->hasPotentiallyUnavailableCaseValue()
+            && canDeriveComparable(DC, enumDecl); 
+
+        // "Simple" enums without availability attributes can explicitly derive
+        // a CaseIterable conformance.
+        //
+        // FIXME: Lift the availability restriction.
+      case KnownDerivableProtocolKind::CaseIterable:
+        return !enumDecl->hasPotentiallyUnavailableCaseValue()
+            && enumDecl->hasOnlyCasesWithoutAssociatedValues();
+
+        // @objc enums can explicitly derive their _BridgedNSError conformance.
+      case KnownDerivableProtocolKind::BridgedNSError:
+        return enumDecl->isObjC() && enumDecl->hasCases()
+            && enumDecl->hasOnlyCasesWithoutAssociatedValues();
+
+        // Enums without associated values and enums with a raw type of String
+        // or Int can explicitly derive CodingKey conformance.
+      case KnownDerivableProtocolKind::CodingKey: {
+        Type rawType = enumDecl->getRawType();
+        if (rawType) {
+          return rawType->isString() || rawType->isInt();
+        }
+
+        // hasOnlyCasesWithoutAssociatedValues will return true for empty enums;
+        // empty enums are allowed to conform as well.
+        return enumDecl->hasOnlyCasesWithoutAssociatedValues();
+      }
+
+      default:
+        return false;
+    }
+  } else if (isa<StructDecl>(Nominal)) {
+    switch (*derivableKind) {
+    case KnownDerivableProtocolKind::Equatable:
+      // Structs can explicitly derive Equatable conformance.
+      return canDeriveEquatable(DC, Nominal);
+    default:
+      return false;
+    }
+  }
+  return false;
+}
+
+SmallVector<VarDecl *, 3>
+DerivedConformance::storedPropertiesNotConformingToProtocol(
+    DeclContext *DC, StructDecl *theStruct, ProtocolDecl *protocol) {
+  auto storedProperties = theStruct->getStoredProperties();
+  SmallVector<VarDecl *, 3> nonconformingProperties;
+  for (auto propertyDecl : storedProperties) {
+    if (!propertyDecl->isUserAccessible())
+      continue;
+
+    auto type = propertyDecl->getValueInterfaceType();
+    if (!type)
+      nonconformingProperties.push_back(propertyDecl);
+
+    if (!checkConformance(DC->mapTypeIntoContext(type), protocol)) {
+      nonconformingProperties.push_back(propertyDecl);
+    }
+  }
+  return nonconformingProperties;
+}
+
+void DerivedConformance::tryDiagnoseFailedDerivation(DeclContext *DC,
+                                                     NominalTypeDecl *nominal,
+                                                     ProtocolDecl *protocol) {
+  auto knownProtocol = protocol->getKnownProtocolKind();
+  if (!knownProtocol)
+    return;
+  
+  if (*knownProtocol == KnownProtocolKind::Equatable) {
+    tryDiagnoseFailedEquatableDerivation(DC, nominal);
+  }
+
+  if (*knownProtocol == KnownProtocolKind::Hashable) {
+    tryDiagnoseFailedHashableDerivation(DC, nominal);
+  }
+
+  if (*knownProtocol == KnownProtocolKind::Comparable) {
+    tryDiagnoseFailedComparableDerivation(DC, nominal);
+  }
+
+  if (*knownProtocol == KnownProtocolKind::DistributedActor) {
+    tryDiagnoseFailedDistributedActorDerivation(DC, nominal);
+  }
+
+  if (*knownProtocol == KnownProtocolKind::DistributedActorSystem) {
+    tryDiagnoseFailedDistributedActorSystemDerivation(DC, nominal);
+  }
+}
+
+void DerivedConformance::diagnoseAnyNonConformingMemberTypes(
+    DeclContext *DC, NominalTypeDecl *nominal, ProtocolDecl *protocol) {
+  ASTContext &ctx = DC->getASTContext();
+
+  if (auto *enumDecl = dyn_cast<EnumDecl>(nominal)) {
+    auto nonconformingAssociatedTypes =
+        associatedValuesNotConformingToProtocol(DC, enumDecl, protocol);
+    for (auto *typeToDiagnose : nonconformingAssociatedTypes) {
+      SourceLoc reprLoc;
+      if (auto *repr = typeToDiagnose->getTypeRepr())
+        reprLoc = repr->getStartLoc();
+      ctx.Diags.diagnose(
+          reprLoc, diag::missing_member_type_conformance_prevents_synthesis,
+          NonconformingMemberKind::AssociatedValue,
+          typeToDiagnose->getInterfaceType(),
+          protocol->getDeclaredInterfaceType(),
+          nominal->getDeclaredInterfaceType());
+    }
+  }
+
+  if (auto *structDecl = dyn_cast<StructDecl>(nominal)) {
+    auto nonconformingStoredProperties =
+        storedPropertiesNotConformingToProtocol(DC, structDecl, protocol);
+    for (auto *propertyToDiagnose : nonconformingStoredProperties) {
+      ctx.Diags.diagnose(
+          propertyToDiagnose->getLoc(),
+          diag::missing_member_type_conformance_prevents_synthesis,
+          NonconformingMemberKind::StoredProperty,
+          propertyToDiagnose->getInterfaceType(),
+          protocol->getDeclaredInterfaceType(),
+          nominal->getDeclaredInterfaceType());
+    }
+  }
+}
+
+void DerivedConformance::diagnoseIfSynthesisUnsupportedForDecl(
+    NominalTypeDecl *nominal, ProtocolDecl *protocol) {
+  auto shouldDiagnose = false;
+
+  if (protocol->isSpecificProtocol(KnownProtocolKind::Equatable) ||
+      protocol->isSpecificProtocol(KnownProtocolKind::Hashable)) {
+    shouldDiagnose = isa<ClassDecl>(nominal);
+  }
+
+  if (protocol->isSpecificProtocol(KnownProtocolKind::Comparable)) {
+    shouldDiagnose = !isa<EnumDecl>(nominal);
+  }
+
+  if (isa<BuiltinTupleDecl>(nominal))
+    shouldDiagnose = false;
+
+  if (shouldDiagnose) {
+    auto &ctx = nominal->getASTContext();
+    ctx.Diags.diagnose(nominal->getLoc(),
+                       diag::automatic_protocol_synthesis_unsupported, protocol,
+                       nominal);
+  }
+}
+
+ValueDecl *DerivedConformance::getDerivableRequirement(NominalTypeDecl *nominal,
+                                                       ValueDecl *requirement) {
+  // Note: whenever you update this function, also update
+  // deriveProtocolRequirement.
+  ASTContext &ctx = nominal->getASTContext();
+  const auto name = requirement->getName();
+
+  // Local function that retrieves the requirement with the same name as
+  // the provided requirement, but within the given known protocol.
+  auto getRequirement = [&](KnownProtocolKind kind) -> ValueDecl * {
+    // Dig out the protocol.
+    auto proto = ctx.getProtocol(kind);
+    if (!proto) return nullptr;
+
+    auto conformance = lookupConformance(
+        nominal->getDeclaredInterfaceType(), proto);
+    if (conformance.isConcrete()) {
+      // Check whether this nominal type derives conformances to the protocol.
+      if (!DerivedConformance::derivesProtocolConformance(
+            conformance.getConcrete()->getRootNormalConformance()))
+        return nullptr;
+    }
+
+    // Retrieve the requirement.
+    return proto->getSingleRequirement(name);
+  };
+
+  // Properties.
+  if (isa<VarDecl>(requirement)) {
+    // RawRepresentable.rawValue
+    if (name.isSimpleName(ctx.Id_rawValue))
+      return getRequirement(KnownProtocolKind::RawRepresentable);
+
+    // Hashable.hashValue
+    if (name.isSimpleName(ctx.Id_hashValue))
+      return getRequirement(KnownProtocolKind::Hashable);
+
+    // CaseIterable.allValues
+    if (name.isSimpleName(ctx.Id_allCases))
+      return getRequirement(KnownProtocolKind::CaseIterable);
+
+    // _BridgedNSError._nsErrorDomain
+    if (name.isSimpleName(ctx.Id_nsErrorDomain))
+      return getRequirement(KnownProtocolKind::BridgedNSError);
+
+    // CodingKey.stringValue
+    if (name.isSimpleName(ctx.Id_stringValue))
+      return getRequirement(KnownProtocolKind::CodingKey);
+
+    // CodingKey.intValue
+    if (name.isSimpleName(ctx.Id_intValue))
+      return getRequirement(KnownProtocolKind::CodingKey);
+
+    // AdditiveArithmetic.zero
+    if (name.isSimpleName(ctx.Id_zero))
+      return getRequirement(KnownProtocolKind::AdditiveArithmetic);
+
+    // Actor.unownedExecutor
+    if (name.isSimpleName(ctx.Id_unownedExecutor)) {
+      if (nominal->isDistributedActor()) {
+        return getRequirement(KnownProtocolKind::DistributedActor);
+      } else {
+        return getRequirement(KnownProtocolKind::Actor);
+      }
+    }
+
+    // DistributedActor.id
+    if (name.isSimpleName(ctx.Id_id))
+      return getRequirement(KnownProtocolKind::DistributedActor);
+
+    // DistributedActor.actorSystem
+    if (name.isSimpleName(ctx.Id_actorSystem))
+      return getRequirement(KnownProtocolKind::DistributedActor);
+
+    return nullptr;
+  }
+
+  // Functions.
+  if (auto func = dyn_cast<FuncDecl>(requirement)) {
+    if (func->isOperator() && name.getBaseName() == "<")
+      return getRequirement(KnownProtocolKind::Comparable);
+    
+    if (func->isOperator() && name.getBaseName() == "==")
+      return getRequirement(KnownProtocolKind::Equatable);
+
+    // AdditiveArithmetic.+
+    // AdditiveArithmetic.-
+    if (func->isOperator() && name.getArgumentNames().size() == 2 &&
+        (name.getBaseName() == "+" || name.getBaseName() == "-")) {
+      return getRequirement(KnownProtocolKind::AdditiveArithmetic);
+    }
+
+    // Differentiable.move(by:)
+    if (name.isCompoundName() && name.getBaseName() == ctx.Id_move) {
+      auto argumentNames = name.getArgumentNames();
+      if (argumentNames.size() == 1 && argumentNames[0] == ctx.Id_by)
+        return getRequirement(KnownProtocolKind::Differentiable);
+    }
+
+    // Encodable.encode(to: Encoder)
+    if (name.isCompoundName() && name.getBaseName() == ctx.Id_encode) {
+      auto argumentNames = name.getArgumentNames();
+      if (argumentNames.size() == 1 && argumentNames[0] == ctx.Id_to)
+        return getRequirement(KnownProtocolKind::Encodable);
+    }
+
+    // Hashable.hash(into: inout Hasher)
+    if (name.isCompoundName() && name.getBaseName() == ctx.Id_hash) {
+      auto argumentNames = name.getArgumentNames();
+      if (argumentNames.size() == 1 && argumentNames[0] == ctx.Id_into)
+        return getRequirement(KnownProtocolKind::Hashable);
+    }
+
+    // static DistributedActor.resolve(id:using:)
+    if (name.isCompoundName() && name.getBaseName() == ctx.Id_resolve &&
+        func->isStatic()) {
+      auto argumentNames = name.getArgumentNames();
+      if (argumentNames.size() == 2 &&
+          argumentNames[0] == ctx.Id_id &&
+          argumentNames[1] == ctx.Id_using) {
+        return getRequirement(KnownProtocolKind::DistributedActor);
+      }
+    }
+
+    // DistributedActor.actorSystem
+    if (name.isCompoundName() &&
+        name.getBaseName() == ctx.Id_invokeHandlerOnReturn)
+      return getRequirement(KnownProtocolKind::DistributedActorSystem);
+
+    return nullptr;
+  }
+
+  // Initializers.
+  if (auto ctor = dyn_cast<ConstructorDecl>(requirement)) {
+    auto argumentNames = name.getArgumentNames();
+    if (argumentNames.size() == 1) {
+      if (argumentNames[0] == ctx.Id_rawValue)
+        return getRequirement(KnownProtocolKind::RawRepresentable);
+
+      // CodingKey.init?(stringValue:), CodingKey.init?(intValue:)
+      if (ctor->isFailable() &&
+          !ctor->isImplicitlyUnwrappedOptional() &&
+          (argumentNames[0] == ctx.Id_stringValue ||
+           argumentNames[0] == ctx.Id_intValue))
+        return getRequirement(KnownProtocolKind::CodingKey);
+
+      // Decodable.init(from: Decoder)
+      if (argumentNames[0] == ctx.Id_from)
+        return getRequirement(KnownProtocolKind::Decodable);
+    }
+
+    return nullptr;
+  }
+
+  // Associated types.
+  if (isa<AssociatedTypeDecl>(requirement)) {
+    // RawRepresentable.RawValue
+    if (name.isSimpleName(ctx.Id_RawValue))
+      return getRequirement(KnownProtocolKind::RawRepresentable);
+
+    // CaseIterable.AllCases
+    if (name.isSimpleName(ctx.Id_AllCases))
+      return getRequirement(KnownProtocolKind::CaseIterable);
+
+    // Differentiable.TangentVector
+    if (name.isSimpleName(ctx.Id_TangentVector))
+      return getRequirement(KnownProtocolKind::Differentiable);
+
+    return nullptr;
+  }
+
+  return nullptr;
+}
+
+DeclRefExpr *
+DerivedConformance::createSelfDeclRef(AbstractFunctionDecl *fn) {
+  ASTContext &C = fn->getASTContext();
+
+  auto selfDecl = fn->getImplicitSelfDecl();
+  return new (C) DeclRefExpr(selfDecl, DeclNameLoc(), /*implicit*/true);
+}
+
+CallExpr *
+DerivedConformance::createBuiltinCall(ASTContext &ctx,
+                                      BuiltinValueKind builtin,
+                                      ArrayRef<Type> typeArgs,
+                                      ArrayRef<Expr *> args) {
+  auto name = ctx.getIdentifier(getBuiltinName(builtin));
+  auto decl = getBuiltinValueDecl(ctx, name);
+  assert(decl);
+
+  ConcreteDeclRef declRef = decl;
+  auto fnType = decl->getInterfaceType();
+  if (auto genericFnType = fnType->getAs<GenericFunctionType>()) {
+    auto generics = genericFnType->getGenericSignature();
+    auto subs = SubstitutionMap::get(generics, typeArgs,
+                                     LookUpConformanceInModule{});
+    declRef = ConcreteDeclRef(decl, subs);
+    fnType = genericFnType->substGenericArgs(subs);
+  } else {
+    assert(typeArgs.empty());
+  }
+
+  auto resultType = fnType->castTo<FunctionType>()->getResult();
+
+  Expr *ref = new (ctx) DeclRefExpr(declRef, DeclNameLoc(),
+                                    /*Implicit=*/true,
+                                    AccessSemantics::Ordinary, fnType);
+  auto *argList = ArgumentList::forImplicitUnlabeled(ctx, args);
+  auto *call = CallExpr::createImplicit(ctx, ref, argList);
+  call->setType(resultType);
+  call->setThrows(nullptr);
+
+  return call;
+}
+
+CallExpr *DerivedConformance::createDiagnoseUnavailableCodeReachedCallExpr(
+    ASTContext &ctx) {
+  FuncDecl *diagnoseDecl = ctx.getDiagnoseUnavailableCodeReached();
+  assert(diagnoseDecl);
+  auto diagnoseDeclRefExpr =
+      new (ctx) DeclRefExpr(diagnoseDecl, DeclNameLoc(), true);
+  diagnoseDeclRefExpr->setType(diagnoseDecl->getInterfaceType());
+  auto argList = ArgumentList::createImplicit(ctx, {});
+  auto callExpr = CallExpr::createImplicit(ctx, diagnoseDeclRefExpr, argList);
+  callExpr->setType(ctx.getNeverType());
+  callExpr->setThrows(nullptr);
+  return callExpr;
+}
+
+AccessorDecl *
+DerivedConformance::addGetterToReadOnlyDerivedProperty(VarDecl *property) {
+  auto getter = declareDerivedPropertyGetter(property);
+
+  property->setImplInfo(StorageImplInfo::getImmutableComputed());
+  property->setAccessors(SourceLoc(), {getter}, SourceLoc());
+
+  return getter;
+}
+
+AccessorDecl *
+DerivedConformance::declareDerivedPropertyGetter(VarDecl *property) {
+  auto &C = property->getASTContext();
+  auto parentDC = property->getDeclContext();
+  ParameterList *params = ParameterList::createEmpty(C);
+
+  auto getterDecl = AccessorDecl::create(
+      C,
+      /*FuncLoc=*/SourceLoc(), /*AccessorKeywordLoc=*/SourceLoc(),
+      AccessorKind::Get, property,
+      /*Async=*/false, /*AsyncLoc=*/SourceLoc(),
+      /*Throws=*/false, /*ThrowsLoc=*/SourceLoc(), /*ThrownType=*/TypeLoc(),
+      params, property->getInterfaceType(), parentDC);
+  getterDecl->setImplicit();
+  getterDecl->setIsTransparent(false);
+  getterDecl->copyFormalAccessFrom(property);
+
+  return getterDecl;
+}
+
+static VarDecl::Introducer
+mapIntroducer(DerivedConformance::SynthesizedIntroducer intro) {
+  switch (intro) {
+  case DerivedConformance::SynthesizedIntroducer::Let:
+    return VarDecl::Introducer::Let;
+  case DerivedConformance::SynthesizedIntroducer::Var:
+    return VarDecl::Introducer::Var;
+  }
+  llvm_unreachable("Invalid synthesized introducer!");
+}
+
+std::pair<VarDecl *, PatternBindingDecl *>
+DerivedConformance::declareDerivedProperty(SynthesizedIntroducer intro,
+                                           Identifier name,
+                                           Type propertyInterfaceType,
+                                           bool isStatic, bool isFinal) {
+  auto parentDC = getConformanceContext();
+
+  VarDecl *propDecl = new (Context) VarDecl(
+      /*IsStatic*/ isStatic, mapIntroducer(intro), SourceLoc(), name, parentDC);
+  propDecl->setImplicit();
+  propDecl->setSynthesized();
+  propDecl->copyFormalAccessFrom(Nominal, /*sourceIsParentContext*/ true);
+  propDecl->setInterfaceType(propertyInterfaceType);
+
+  auto propertyContextType =
+      getConformanceContext()->mapTypeIntoContext(propertyInterfaceType);
+
+  Pattern *propPat =
+      NamedPattern::createImplicit(Context, propDecl, propertyContextType);
+
+  propPat = TypedPattern::createImplicit(Context, propPat, propertyContextType);
+
+  auto *pbDecl = PatternBindingDecl::createImplicit(
+      Context, StaticSpellingKind::None, propPat, /*InitExpr*/ nullptr,
+      parentDC);
+  return {propDecl, pbDecl};
+}
+
+bool DerivedConformance::checkAndDiagnoseDisallowedContext(
+    ValueDecl *synthesizing) const {
+  // In general, conformances can't be synthesized in extensions across files;
+  // but we have to allow it as a special case for Equatable and Hashable on
+  // enums with no associated values to preserve source compatibility.
+  bool allowCrossfileExtensions = false;
+  if (Protocol->isSpecificProtocol(KnownProtocolKind::Equatable) ||
+      Protocol->isSpecificProtocol(KnownProtocolKind::Hashable)) {
+    auto ED = dyn_cast<EnumDecl>(Nominal);
+    allowCrossfileExtensions = ED && ED->hasOnlyCasesWithoutAssociatedValues();
+  }
+
+  if (!allowCrossfileExtensions &&
+      Nominal->getModuleScopeContext() !=
+          getConformanceContext()->getModuleScopeContext()) {
+    ConformanceDecl->diagnose(diag::cannot_synthesize_in_crossfile_extension,
+                              Nominal, synthesizing->getName(),
+                              getProtocolType());
+    Nominal->diagnose(diag::kind_declared_here, DescriptiveDeclKind::Type);
+
+    // Try to insert a stub.
+    auto Extension = cast<ExtensionDecl>(getConformanceContext());
+    auto FixitLocation = Extension->getBraces().Start;
+    llvm::SmallString<128> Text;
+    {
+      llvm::raw_svector_ostream SS(Text);
+      swift::printRequirementStub(synthesizing, Nominal,
+                                  Nominal->getDeclaredType(),
+                                  Extension->getStartLoc(), SS);
+      if (!Text.empty()) {
+        ConformanceDecl->diagnose(diag::missing_witnesses_general)
+          .fixItInsertAfter(FixitLocation, Text.str());
+      }
+    }
+    return true;
+  }
+
+  // A non-final class can't have a protocol-witnesses initializer in an
+  // extension.
+  if (auto CD = dyn_cast<ClassDecl>(Nominal)) {
+    if (!CD->isSemanticallyFinal() && isa<ConstructorDecl>(synthesizing) &&
+        isa<ExtensionDecl>(ConformanceDecl)) {
+      ConformanceDecl->diagnose(
+          diag::cannot_synthesize_init_in_extension_of_nonfinal,
+          getProtocolType(), synthesizing->getName());
+      return true;
+    }
+  }
+
+  if (auto ED = dyn_cast<EnumDecl>(Nominal)) {
+    if (ED->getAllCases().empty() &&
+        (Protocol->isSpecificProtocol(KnownProtocolKind::Encodable) ||
+         Protocol->isSpecificProtocol(KnownProtocolKind::Decodable))) {
+      ED->diagnose(diag::codable_synthesis_empty_enum_not_supported,
+                   getProtocolType(), Nominal->getBaseIdentifier());
+      return false;
+    }
+  }
+
+  return false;
+}
+
+/// Returns a generated guard statement that checks whether the given lhs and
+/// rhs expressions are equal. If not equal, the else block for the guard
+/// returns `guardReturnValue`.
+/// \p C The AST context.
+/// \p lhsExpr The first expression to compare for equality.
+/// \p rhsExpr The second expression to compare for equality.
+/// \p guardReturnValue The expression to return if the two sides are not equal 
+GuardStmt *DerivedConformance::returnIfNotEqualGuard(ASTContext &C,
+                                        Expr *lhsExpr,
+                                        Expr *rhsExpr, 
+                                        Expr *guardReturnValue) {
+  SmallVector<StmtConditionElement, 1> conditions;
+  SmallVector<ASTNode, 1> statements;
+
+  auto *returnStmt = ReturnStmt::createImplicit(C, guardReturnValue);
+  statements.push_back(returnStmt);
+
+  // Next, generate the condition being checked.
+  // lhs == rhs
+  auto cmpFuncExpr = new (C) UnresolvedDeclRefExpr(
+    DeclNameRef(C.Id_EqualsOperator), DeclRefKind::BinaryOperator,
+    DeclNameLoc());
+  auto *cmpExpr = BinaryExpr::create(C, lhsExpr, cmpFuncExpr, rhsExpr,
+                                     /*implicit*/ true);
+  conditions.emplace_back(cmpExpr);
+
+  // Build and return the complete guard statement.
+  // guard lhs == rhs else { return lhs < rhs }
+  auto body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc());
+  return new (C) GuardStmt(SourceLoc(), C.AllocateCopy(conditions), body);
+}
+/// Returns a generated guard statement that checks whether the given lhs and
+/// rhs expressions are equal. If not equal, the else block for the guard
+/// returns `false`.
+/// \p C The AST context.
+/// \p lhsExpr The first expression to compare for equality.
+/// \p rhsExpr The second expression to compare for equality. 
+GuardStmt *DerivedConformance::returnFalseIfNotEqualGuard(ASTContext &C,
+                                        Expr *lhsExpr,
+                                        Expr *rhsExpr) {
+  // return false
+  auto falseExpr = new (C) BooleanLiteralExpr(false, SourceLoc(), true);
+  return returnIfNotEqualGuard(C, lhsExpr, rhsExpr, falseExpr);
+}
+/// Returns a generated guard statement that checks whether the given expr is true.
+/// If it is false, the else block for the guard returns `nil`.
+/// \p C The AST context.
+/// \p testExpr The expression that should be tested.
+/// \p baseType The wrapped type of the to-be-returned Optional<Wrapped>.
+GuardStmt *DerivedConformance::returnNilIfFalseGuardTypeChecked(ASTContext &C,
+                                        Expr *testExpr,
+                                        Type optionalWrappedType) {
+  auto nilExpr = new (C) NilLiteralExpr(SourceLoc(), /*implicit=*/true);
+  nilExpr->setType(optionalWrappedType->wrapInOptionalType());
+
+  SmallVector<StmtConditionElement, 1> conditions;
+  SmallVector<ASTNode, 1> statements;
+
+  auto *returnStmt = ReturnStmt::createImplicit(C, nilExpr);
+  statements.push_back(returnStmt);
+
+  // Next, generate the condition being checked.
+  conditions.emplace_back(testExpr);
+
+  // Build and return the complete guard statement.
+  // guard lhs == rhs else { return lhs < rhs }
+  auto body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc());
+  return new (C) GuardStmt(SourceLoc(), C.AllocateCopy(conditions), body);
+}
+/// Returns a generated guard statement that checks whether the given lhs and
+/// rhs expressions are equal. If not equal, the else block for the guard
+/// returns lhs < rhs.
+/// \p C The AST context.
+/// \p lhsExpr The first expression to compare for equality.
+/// \p rhsExpr The second expression to compare for equality. 
+GuardStmt *DerivedConformance::returnComparisonIfNotEqualGuard(ASTContext &C,
+                                        Expr *lhsExpr,
+                                        Expr *rhsExpr) {
+  // return lhs < rhs
+  auto ltFuncExpr = new (C) UnresolvedDeclRefExpr(
+    DeclNameRef(C.Id_LessThanOperator), DeclRefKind::BinaryOperator,
+    DeclNameLoc());
+  auto *ltExpr = BinaryExpr::create(C, lhsExpr, ltFuncExpr, rhsExpr,
+                                    /*implicit*/ true);
+  return returnIfNotEqualGuard(C, lhsExpr, rhsExpr, ltExpr);
+}
+
+/// Build a type-checked integer literal.
+static IntegerLiteralExpr *buildIntegerLiteral(ASTContext &C, unsigned index) {
+  Type intType = C.getIntType();
+
+  auto literal = IntegerLiteralExpr::createFromUnsigned(C, index, SourceLoc());
+  literal->setType(intType);
+  literal->setBuiltinInitializer(C.getIntBuiltinInitDecl(C.getIntDecl()));
+
+  return literal;
+}
+
+/// Create AST statements which convert from an enum to an Int with a switch.
+/// \p stmts The generated statements are appended to this vector.
+/// \p parentDC Either an extension or the enum itself.
+/// \p enumDecl The enum declaration.
+/// \p enumVarDecl The enum input variable.
+/// \p funcDecl The parent function.
+/// \p indexName The name of the output variable.
+/// \return A DeclRefExpr of the output variable (of type Int).
+DeclRefExpr *DerivedConformance::convertEnumToIndex(SmallVectorImpl<ASTNode> &stmts,
+                                       DeclContext *parentDC,
+                                       EnumDecl *enumDecl,
+                                       VarDecl *enumVarDecl,
+                                       AbstractFunctionDecl *funcDecl,
+                                       const char *indexName) {
+  ASTContext &C = enumDecl->getASTContext();
+  Type enumType = enumVarDecl->getTypeInContext();
+  Type intType = C.getIntType();
+
+  auto indexVar = new (C) VarDecl(/*IsStatic*/false, VarDecl::Introducer::Var,
+                                  SourceLoc(), C.getIdentifier(indexName),
+                                  funcDecl);
+  indexVar->setInterfaceType(intType);
+  indexVar->setImplicit();
+
+  // generate: var indexVar
+  Pattern *indexPat = NamedPattern::createImplicit(C, indexVar, intType);
+  indexPat = TypedPattern::createImplicit(C, indexPat, intType);
+
+  auto *indexBind = PatternBindingDecl::createImplicit(
+      C, StaticSpellingKind::None, indexPat, /*InitExpr*/ nullptr, funcDecl);
+
+  unsigned index = 0;
+  SmallVector<CaseStmt *, 4> cases;
+  for (auto elt : enumDecl->getAllElements()) {
+    if (auto *unavailableElementCase =
+            DerivedConformance::unavailableEnumElementCaseStmt(enumType, elt,
+                                                               funcDecl)) {
+      cases.push_back(unavailableElementCase);
+      continue;
+    }
+
+    // generate: case .<Case>:
+    auto *pat = EnumElementPattern::createImplicit(
+        enumType, elt, /*subPattern*/ nullptr, /*DC*/ funcDecl);
+
+    auto labelItem = CaseLabelItem(pat);
+
+    // generate: indexVar = <index>
+    auto indexExpr = buildIntegerLiteral(C, index++);
+
+    auto indexRef = new (C) DeclRefExpr(indexVar, DeclNameLoc(),
+                                        /*implicit*/true,
+                                        AccessSemantics::Ordinary,
+                                        LValueType::get(intType));
+    auto assignExpr = new (C) AssignExpr(indexRef, SourceLoc(),
+                                         indexExpr, /*implicit*/ true);
+    assignExpr->setType(TupleType::getEmpty(C));
+    auto body = BraceStmt::create(C, SourceLoc(), ASTNode(assignExpr),
+                                  SourceLoc());
+    cases.push_back(
+        CaseStmt::createImplicit(C, CaseParentKind::Switch, labelItem, body));
+  }
+
+  // generate: switch enumVar { }
+  auto enumRef = new (C) DeclRefExpr(enumVarDecl, DeclNameLoc(),
+                                     /*implicit*/true,
+                                     AccessSemantics::Ordinary,
+                                     enumVarDecl->getTypeInContext());
+  auto switchStmt =
+      SwitchStmt::createImplicit(LabeledStmtInfo(), enumRef, cases, C);
+
+  stmts.push_back(indexBind);
+  stmts.push_back(switchStmt);
+
+  return new (C) DeclRefExpr(indexVar, DeclNameLoc(), /*implicit*/ true,
+                             AccessSemantics::Ordinary, intType);
+}
+
+/// Returns the ParamDecl for each associated value of the given enum whose type
+/// does not conform to a protocol
+/// \p theEnum The enum whose elements and associated values should be checked.
+/// \p protocol The protocol being requested.
+/// \return The ParamDecl of each associated value whose type does not conform.
+SmallVector<ParamDecl *, 4>
+DerivedConformance::associatedValuesNotConformingToProtocol(
+    DeclContext *DC, EnumDecl *theEnum, ProtocolDecl *protocol) {
+  SmallVector<ParamDecl *, 4> nonconformingAssociatedValues;
+  for (auto elt : theEnum->getAllElements()) {
+    auto PL = elt->getParameterList();
+    if (!PL)
+      continue;
+
+    for (auto param : *PL) {
+      auto type = param->getInterfaceType();
+      if (checkConformance(DC->mapTypeIntoContext(type), protocol).isInvalid()) {
+        nonconformingAssociatedValues.push_back(param);
+      }
+    }
+  }
+  return nonconformingAssociatedValues;
+}
+
+/// Returns true if, for every element of the given enum, it either has no
+/// associated values or all of them conform to a protocol.
+/// \p theEnum The enum whose elements and associated values should be checked.
+/// \p protocol The protocol being requested.
+/// \return True if all associated values of all elements of the enum conform.
+bool DerivedConformance::allAssociatedValuesConformToProtocol(DeclContext *DC,
+                                                 EnumDecl *theEnum,
+                                                 ProtocolDecl *protocol) {
+  return associatedValuesNotConformingToProtocol(DC, theEnum, protocol).empty();
+}
+
+/// Returns the pattern used to match and bind the associated values (if any) of
+/// an enum case.
+/// \p enumElementDecl The enum element to match.
+/// \p varPrefix The prefix character for variable names (e.g., a0, a1, ...).
+/// \p varContext The context into which payload variables should be declared.
+/// \p boundVars The array to which the pattern's variables will be appended.
+/// \p useLabels If the argument has a label, use it instead of the generated
+/// name.
+Pattern *DerivedConformance::enumElementPayloadSubpattern(
+    EnumElementDecl *enumElementDecl, char varPrefix, DeclContext *varContext,
+    SmallVectorImpl<VarDecl *> &boundVars, bool useLabels) {
+  auto parentDC = enumElementDecl->getDeclContext();
+  ASTContext &C = parentDC->getASTContext();
+
+  // No arguments, so no subpattern to match.
+  if (!enumElementDecl->hasAssociatedValues())
+    return nullptr;
+
+  auto payloadType = enumElementDecl->getPayloadInterfaceType();
+  if (auto tupleType = payloadType->getAs<TupleType>()) {
+    // Either multiple (labeled or unlabeled) arguments, or one labeled
+    // argument. Return a tuple pattern that matches the enum element in arity,
+    // types, and labels. For example:
+    // case a(x: Int) => (x: let a0)
+    // case b(Int, String) => (let a0, let a1)
+    SmallVector<TuplePatternElt, 4> elementPatterns;
+    int index = 0;
+    for (auto tupleElement : tupleType->getElements()) {
+      VarDecl *payloadVar;
+      if (useLabels && tupleElement.hasName()) {
+        payloadVar =
+            new (C) VarDecl(/*IsStatic*/ false, VarDecl::Introducer::Let,
+                            SourceLoc(), tupleElement.getName(), varContext);
+        payloadVar->setInterfaceType(tupleElement.getType());
+      } else {
+        payloadVar = indexedVarDecl(varPrefix, index++, tupleElement.getType(),
+                                    varContext);
+      }
+      boundVars.push_back(payloadVar);
+
+      auto namedPattern = new (C) NamedPattern(payloadVar);
+      namedPattern->setImplicit();
+      auto letPattern = BindingPattern::createImplicit(
+          C, VarDecl::Introducer::Let, namedPattern);
+      elementPatterns.push_back(TuplePatternElt(tupleElement.getName(),
+                                                SourceLoc(), letPattern));
+    }
+
+    auto pat = TuplePattern::createImplicit(C, elementPatterns);
+    pat->setImplicit();
+    return pat;
+  }
+
+  // Otherwise, a one-argument unlabeled payload. Return a paren pattern whose
+  // underlying type is the same as the payload. For example:
+  // case a(Int) => (let a0)
+  auto payloadVar = indexedVarDecl(varPrefix, 0, payloadType, varContext);
+  boundVars.push_back(payloadVar);
+
+  auto namedPattern = new (C) NamedPattern(payloadVar);
+  namedPattern->setImplicit();
+  auto letPattern = new (C)
+      BindingPattern(SourceLoc(), VarDecl::Introducer::Let, namedPattern);
+  return ParenPattern::createImplicit(C, letPattern);
+}
+
+CaseStmt *DerivedConformance::unavailableEnumElementCaseStmt(
+    Type enumType, EnumElementDecl *elt, DeclContext *parentDC,
+    unsigned subPatternCount) {
+  assert(subPatternCount > 0);
+
+  ASTContext &C = parentDC->getASTContext();
+  if (!elt->isUnreachableAtRuntime() ||
+      elt->getParentEnum()->isUnreachableAtRuntime())
+    return nullptr;
+
+  // If the stdlib isn't new enough to contain the helper function for
+  // diagnosing execution of unavailable code then just synthesize this case
+  // normally.
+  if (!C.getDiagnoseUnavailableCodeReached())
+    return nullptr;
+
+  auto createElementPattern = [&]() -> EnumElementPattern * {
+    // .<elt>
+    return EnumElementPattern::createImplicit(
+        enumType, elt, /*subPattern*/ nullptr, /*DC*/ parentDC);
+  };
+
+  Pattern *labelItemPattern;
+  if (subPatternCount > 1) {
+    SmallVector<TuplePatternElt, 2> tuplePatternElts;
+    for (unsigned i = 0; i < subPatternCount; i++) {
+      tuplePatternElts.push_back(TuplePatternElt(createElementPattern()));
+    }
+
+    // (.<elt>, ..., .<elt>)
+    auto caseTuplePattern = TuplePattern::createImplicit(C, tuplePatternElts);
+    caseTuplePattern->setImplicit();
+    labelItemPattern = caseTuplePattern;
+  } else {
+    labelItemPattern = createElementPattern();
+  }
+
+  auto labelItem = CaseLabelItem(labelItemPattern);
+  auto *callExpr =
+      DerivedConformance::createDiagnoseUnavailableCodeReachedCallExpr(C);
+  auto body = BraceStmt::create(C, SourceLoc(), {callExpr}, SourceLoc());
+  return CaseStmt::createImplicit(C, CaseParentKind::Switch, labelItem, body);
+}
+
+/// Creates a named variable based on a prefix character and a numeric index.
+/// \p prefixChar The prefix character for the variable's name.
+/// \p index The numeric index to append to the variable's name.
+/// \p type The type of the variable.
+/// \p varContext The context of the variable.
+/// \return A VarDecl named with the prefix and number.
+VarDecl *DerivedConformance::indexedVarDecl(char prefixChar, int index, Type type,
+                               DeclContext *varContext) {
+  ASTContext &C = varContext->getASTContext();
+
+  llvm::SmallString<8> indexVal;
+  indexVal.append(1, prefixChar);
+  APInt(32, index).toString(indexVal, 10, /*signed*/ false);
+  auto indexStr = C.AllocateCopy(indexVal);
+  auto indexStrRef = StringRef(indexStr.data(), indexStr.size());
+
+  auto varDecl = new (C) VarDecl(/*IsStatic*/false, VarDecl::Introducer::Let,
+                                 SourceLoc(), C.getIdentifier(indexStrRef),
+                                 varContext);
+  varDecl->setInterfaceType(type);
+  return varDecl;
+}
+
+bool swift::memberwiseAccessorsRequireActorIsolation(NominalTypeDecl *nominal) {
+  if (!getActorIsolation(nominal).isActorIsolated())
+    return false;
+
+  for (auto property : nominal->getStoredProperties()) {
+    if (!property->isUserAccessible())
+      continue;
+
+    if (!property->isLet())
+      return true;
+  }
+
+  return false;
+}
diff --git a/lib/Sema/DerivedConformance/DerivedConformance.h b/lib/Sema/DerivedConformance/DerivedConformance.h
new file mode 100644
index 0000000000000..39c8110c5c19f
--- /dev/null
+++ b/lib/Sema/DerivedConformance/DerivedConformance.h
@@ -0,0 +1,474 @@
+//===--- DerivedConformance.h -----------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines entry points to synthesize compiler-derived conformances
+//  to certain known protocols.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SEMA_DERIVEDCONFORMANCE_DERIVEDCONFORMANCE_H
+#define SWIFT_SEMA_DERIVEDCONFORMANCE_DERIVEDCONFORMANCE_H
+
+#include "swift/AST/Builtins.h"
+#include "swift/Basic/LLVM.h"
+#include <utility>
+
+namespace swift {
+class AbstractFunctionDecl;
+class AccessorDecl;
+class AssociatedTypeDecl;
+class ASTContext;
+struct ASTNode;
+class CallExpr;
+class CaseStmt;
+class Decl;
+class DeclContext;
+class DeclRefExpr;
+class EnumDecl;
+class EnumElementDecl;
+class Expr;
+class GuardStmt;
+class Identifier;
+class NominalTypeDecl;
+class ParamDecl;
+class Pattern;
+class PatternBindingDecl;
+class ProtocolDecl;
+class StructDecl;
+class Type;
+class TypeDecl;
+class ValueDecl;
+class VarDecl;
+
+class DerivedConformance {
+public:
+  enum class SynthesizedIntroducer : bool { Let, Var };
+
+public:
+  ASTContext &Context;
+  const NormalProtocolConformance *Conformance;
+  Decl *ConformanceDecl;
+  NominalTypeDecl *Nominal;
+  ProtocolDecl *Protocol;
+
+  DerivedConformance(const NormalProtocolConformance *conformance,
+                     NominalTypeDecl *nominal, ProtocolDecl *protocol);
+
+  /// Retrieve the context in which the conformance is declared (either the
+  /// nominal type, or an extension of it) as a \c DeclContext.
+  DeclContext *getConformanceContext() const;
+
+  /// Retrieve the module in which the conformance is declared.
+  ModuleDecl *getParentModule() const;
+
+  /// Add \c children as members of the context that declares the conformance.
+  void addMembersToConformanceContext(ArrayRef<Decl *> children);
+  /// Add \c member right after the \c hint member which may be the tail
+  void addMemberToConformanceContext(Decl *member, Decl* hint);
+  /// Add \c member in front of any other existing members
+  void addMemberToConformanceContext(Decl *member, bool insertAtHead);
+
+  /// Get the declared type of the protocol that this is conformance is for.
+  Type getProtocolType() const;
+
+  /// Returns the VarDecl of each stored property in the given struct whose type
+  /// does not conform to a protocol.
+  /// \p theStruct The struct whose stored properties should be checked.
+  /// \p protocol The protocol being requested.
+  /// \return The VarDecl of each stored property whose type does not conform.
+  static SmallVector<VarDecl *, 3> storedPropertiesNotConformingToProtocol(
+      DeclContext *DC, StructDecl *theStruct, ProtocolDecl *protocol);
+
+  /// True if the type can implicitly derive a conformance for the given
+  /// protocol.
+  ///
+  /// If true, explicit conformance checking will synthesize implicit
+  /// declarations for requirements of the protocol that are not satisfied by
+  /// the type's explicit members.
+  ///
+  /// \param conformance The conformance.
+  ///
+  /// \return True if the type can implicitly derive a conformance for the
+  /// given protocol.
+  static bool derivesProtocolConformance(NormalProtocolConformance *conformance);
+
+  /// Diagnose problems, if any, preventing automatic derivation of protocol
+  /// requirements
+  ///
+  /// \param nominal The nominal type for which we would like to diagnose
+  /// derivation failures
+  ///
+  /// \param protocol The protocol with requirements we would like to diagnose
+  /// derivation failures for
+  static void tryDiagnoseFailedDerivation(DeclContext *DC,
+                                          NominalTypeDecl *nominal,
+                                          ProtocolDecl *protocol);
+
+  /// Diagnose any members which do not conform to the protocol for which
+  /// we were trying to synthesize the conformance to.
+  ///
+  /// \param nominal The nominal type for which we would like to diagnose
+  /// derivation failures
+  ///
+  /// \param protocol The protocol with requirements we would like to diagnose
+  /// derivation failures for
+  static void diagnoseAnyNonConformingMemberTypes(DeclContext *DC,
+                                                  NominalTypeDecl *nominal,
+                                                  ProtocolDecl *protocol);
+
+  /// Diagnose the declaration for which we were trying to synthesize
+  /// the conformance for, if the synthesis is not supported for that
+  /// declaration.
+  ///
+  /// \param nominal The nominal type for which we would like to diagnose
+  /// derivation failures
+  ///
+  /// \param protocol The protocol with requirements we would like to diagnose
+  /// derivation failures for
+  static void diagnoseIfSynthesisUnsupportedForDecl(NominalTypeDecl *nominal,
+                                                    ProtocolDecl *protocol);
+
+  /// Determine the derivable requirement that would satisfy the given
+  /// requirement, if there is one.
+  ///
+  /// \param nominal The nominal type for which we are determining whether to
+  /// derive a witness.
+  ///
+  /// \param requirement The requirement for which we are checking for a
+  /// derivation. This requirement need not be within a derivable protocol,
+  /// because derivable requirements can get restated in inherited unrelated
+  /// or unrelated protocols.
+  ///
+  /// \returns The requirement whose witness could be derived to potentially
+  /// satisfy this given requirement, or NULL if there is no such requirement.
+  static ValueDecl *getDerivableRequirement(NominalTypeDecl *nominal,
+                                            ValueDecl *requirement);
+
+  /// Determine if an AdditiveArithmetic requirement can be derived for a type.
+  ///
+  /// \returns True if the requirement can be derived.
+  static bool canDeriveAdditiveArithmetic(NominalTypeDecl *type,
+                                          DeclContext *DC);
+
+  /// Derive an AdditiveArithmetic requirement for a nominal type.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveAdditiveArithmetic(ValueDecl *requirement);
+
+  /// Determine if a Differentiable requirement can be derived for a nominal
+  /// type.
+  ///
+  /// \returns True if the requirement can be derived.
+  static bool canDeriveDifferentiable(NominalTypeDecl *type, DeclContext *DC,
+                                      ValueDecl *requirement);
+
+  /// Derive a Differentiable requirement for a nominal type.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveDifferentiable(ValueDecl *requirement);
+
+  /// Derive a Differentiable type witness for a nominal type.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  std::pair<Type, TypeDecl *>
+  deriveDifferentiable(AssociatedTypeDecl *assocType);
+
+  /// Derive a CaseIterable requirement for an enum if it has no associated
+  /// values for any of its cases.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveCaseIterable(ValueDecl *requirement);
+
+  /// Derive a CaseIterable type witness for an enum if it has no associated
+  /// values for any of its cases.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  Type deriveCaseIterable(AssociatedTypeDecl *assocType);
+
+  /// Determine if a RawRepresentable requirement can be derived for a type.
+  ///
+  /// This is implemented for non-empty enums without associated values,
+  /// that declare a raw type in the inheritance clause.
+  static bool canDeriveRawRepresentable(DeclContext *DC, NominalTypeDecl *type);
+
+  /// Derive a RawRepresentable requirement for an enum, if it has a valid
+  /// raw type and raw values for all of its cases.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveRawRepresentable(ValueDecl *requirement);
+
+  /// Derive a RawRepresentable type witness for an enum, if it has a valid
+  /// raw type and raw values for all of its cases.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  Type deriveRawRepresentable(AssociatedTypeDecl *assocType);
+
+  /// Determine if a Comparable requirement can be derived for a type.
+  ///
+  /// This is implemented for enums without associated or raw values.
+  ///
+  /// \returns True if the requirement can be derived.
+  static bool canDeriveComparable(DeclContext *DC, EnumDecl *enumeration);
+
+  /// Derive an Equatable requirement for a type.
+  ///
+  /// This is implemented for enums without associated or raw values.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveComparable(ValueDecl *requirement);
+
+  /// Diagnose problems, if any, preventing automatic derivation of Comparable
+  /// requirements
+  ///
+  /// \param nominal The nominal type for which we would like to diagnose
+  /// derivation failures
+  static void tryDiagnoseFailedComparableDerivation(DeclContext *DC,
+                                                    NominalTypeDecl *nominal);
+
+  /// Diagnose problems, if any, preventing automatic derivation of
+  /// DistributedActor requirements
+  ///
+  /// \param nominal The nominal type for which we would like to diagnose
+  /// derivation failures
+  static void tryDiagnoseFailedDistributedActorDerivation(DeclContext *DC,
+                                                    NominalTypeDecl *nominal);
+
+  /// Diagnose problems, if any, preventing automatic derivation of
+  /// DistributedActor requirements
+  ///
+  /// \param nominal The nominal type for which we would like to diagnose
+  /// derivation failures
+  static void
+  tryDiagnoseFailedDistributedActorSystemDerivation(DeclContext *DC,
+                                                    NominalTypeDecl *nominal);
+
+  /// Determine if an Equatable requirement can be derived for a type.
+  ///
+  /// This is implemented for enums without associated values or all-Equatable
+  /// associated values, and for structs with all-Equatable stored properties.
+  ///
+  /// \returns True if the requirement can be derived.
+  static bool canDeriveEquatable(DeclContext *DC, NominalTypeDecl *type);
+
+  /// Derive an Equatable requirement for a type.
+  ///
+  /// This is implemented for enums without associated values or all-Equatable
+  /// associated values, and for structs with all-Equatable stored properties.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveEquatable(ValueDecl *requirement);
+
+  /// Diagnose problems, if any, preventing automatic derivation of Equatable
+  /// requirements
+  ///
+  /// \param nominal The nominal type for which we would like to diagnose
+  /// derivation failures
+  static void tryDiagnoseFailedEquatableDerivation(DeclContext *DC,
+                                                   NominalTypeDecl *nominal);
+
+  /// Determine if a Hashable requirement can be derived for a type.
+  ///
+  /// This is implemented for enums without associated values or all-Hashable
+  /// associated values, and for structs with all-Hashable stored properties.
+  ///
+  /// \returns True if the requirement can be derived.
+  static bool canDeriveHashable(NominalTypeDecl *type);
+
+  /// Derive a Hashable requirement for a type.
+  ///
+  /// This is implemented for enums without associated values or all-Hashable
+  /// associated values, and for structs with all-Hashable stored properties.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveHashable(ValueDecl *requirement);
+
+  /// Diagnose problems, if any, preventing automatic derivation of Hashable
+  /// requirements
+  ///
+  /// \param nominal The nominal type for which we would like to diagnose
+  /// derivation failures
+  static void tryDiagnoseFailedHashableDerivation(DeclContext *DC,
+                                                  NominalTypeDecl *nominal);
+
+  /// Derive a _BridgedNSError requirement for an @objc enum type.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveBridgedNSError(ValueDecl *requirement);
+
+  /// Determine if \c Encodable can be derived for the given type.
+  static bool canDeriveEncodable(NominalTypeDecl *NTD);
+  /// Determine if \c Decodable can be derived for the given type.
+  static bool canDeriveDecodable(NominalTypeDecl *NTD);
+
+  /// Derive a CodingKey requirement for an enum type.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveCodingKey(ValueDecl *requirement);
+
+  /// Derive an Encodable requirement for a struct type.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveEncodable(ValueDecl *requirement);
+
+  /// Derive a Decodable requirement for a struct type.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveDecodable(ValueDecl *requirement);  
+
+  /// Identifiable may need to have the `ID` type witness synthesized explicitly
+  static bool canDeriveIdentifiable(NominalTypeDecl *nominal,
+                                    DeclContext *dc);
+
+  /// Whether we can derive the given DistributedActor requirement in the given context.
+  static bool canDeriveDistributedActor(NominalTypeDecl *nominal,
+                                        DeclContext *dc);
+
+  /// Whether we can derive the given DistributedActorSystem requirements.
+  static bool canDeriveDistributedActorSystem(NominalTypeDecl *nominal,
+                                              DeclContext *dc);
+
+  /// Derive a 'DistributedActor' requirement for an distributed actor.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveDistributedActor(ValueDecl *requirement);
+
+  /// Derive a 'DistributedActorSystem' requirement..
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveDistributedActorSystem(ValueDecl *requirement);
+
+  /// Derive a DistributedActor associated type for a distributed actor.
+  ///
+  /// \returns the derived type member, which will also be added to the type.
+  std::pair<Type, TypeDecl *> deriveDistributedActor(
+      AssociatedTypeDecl *assocType);
+
+  /// Determine if \c Actor can be derived for the given type.
+  static bool canDeriveActor(DeclContext *DC, NominalTypeDecl *NTD);
+
+  /// Derive an Actor witness for an actor type.
+  ///
+  /// \returns the derived member, which will also be added to the type.
+  ValueDecl *deriveActor(ValueDecl *requirement);
+
+  /// Declare a read-only property.
+  std::pair<VarDecl *, PatternBindingDecl *>
+  declareDerivedProperty(SynthesizedIntroducer intro, Identifier name,
+                         Type propertyContextType, bool isStatic, bool isFinal);
+
+  /// Add a getter to a derived property.  The property becomes read-only.
+  static AccessorDecl *addGetterToReadOnlyDerivedProperty(VarDecl *property);
+
+  /// Declare a getter for a derived property.
+  /// The getter will not be added to the property yet.
+  static AccessorDecl *declareDerivedPropertyGetter(VarDecl *property);
+
+  /// Build a reference to the 'self' decl of a derived function.
+  static DeclRefExpr *createSelfDeclRef(AbstractFunctionDecl *fn);
+
+  /// Build a builtin call.  By default, the call is assumed not to throw.
+  static CallExpr *createBuiltinCall(ASTContext &ctx,
+                                     BuiltinValueKind builtin,
+                                     ArrayRef<Type> typeArgs,
+                                     ArrayRef<Expr *> args);
+
+  /// Build a call to the stdlib function that should be called when unavailable
+  /// code is reached unexpectedly.
+  static CallExpr *
+  createDiagnoseUnavailableCodeReachedCallExpr(ASTContext &ctx);
+
+  /// Returns true if this derivation is trying to use a context that isn't
+  /// appropriate for deriving.
+  ///
+  /// \param synthesizing The decl that is being synthesized.
+  bool checkAndDiagnoseDisallowedContext(ValueDecl *synthesizing) const;
+
+  /// Returns a generated guard statement that checks whether the given lhs and
+  /// rhs expressions are equal. If not equal, the else block for the guard
+  /// returns `guardReturnValue`.
+  /// \p C The AST context.
+  /// \p lhsExpr The first expression to compare for equality.
+  /// \p rhsExpr The second expression to compare for equality.
+  /// \p guardReturnValue The expression to return if the two sides are not
+  /// equal
+  static GuardStmt *returnIfNotEqualGuard(ASTContext &C, Expr *lhsExpr,
+                                          Expr *rhsExpr,
+                                          Expr *guardReturnValue);
+  // return false
+  static GuardStmt *returnFalseIfNotEqualGuard(ASTContext &C, Expr *lhsExpr,
+                                               Expr *rhsExpr);
+
+  // Return `nil` is the `testExp` is `false`.
+  static GuardStmt *returnNilIfFalseGuardTypeChecked(ASTContext &C,
+                                                     Expr *testExpr,
+                                                     Type optionalWrappedType);
+
+  // return lhs < rhs
+  static GuardStmt *
+  returnComparisonIfNotEqualGuard(ASTContext &C, Expr *lhsExpr, Expr *rhsExpr);
+
+  /// Returns the ParamDecl for each associated value of the given enum whose
+  /// type does not conform to a protocol \p theEnum The enum whose elements and
+  /// associated values should be checked. \p protocol The protocol being
+  /// requested. \return The ParamDecl of each associated value whose type does
+  /// not conform.
+  static SmallVector<ParamDecl *, 4>
+  associatedValuesNotConformingToProtocol(DeclContext *DC, EnumDecl *theEnum,
+                                          ProtocolDecl *protocol);
+
+  /// Returns true if, for every element of the given enum, it either has no
+  /// associated values or all of them conform to a protocol.
+  /// \p theEnum The enum whose elements and associated values should be
+  /// checked. \p protocol The protocol being requested. \return True if all
+  /// associated values of all elements of the enum conform.
+  static bool allAssociatedValuesConformToProtocol(DeclContext *DC,
+                                                   EnumDecl *theEnum,
+                                                   ProtocolDecl *protocol);
+  /// Create AST statements which convert from an enum to an Int with a switch.
+  /// \p stmts The generated statements are appended to this vector.
+  /// \p parentDC Either an extension or the enum itself.
+  /// \p enumDecl The enum declaration.
+  /// \p enumVarDecl The enum input variable.
+  /// \p funcDecl The parent function.
+  /// \p indexName The name of the output variable.
+  /// \return A DeclRefExpr of the output variable (of type Int).
+  static DeclRefExpr *
+  convertEnumToIndex(SmallVectorImpl<ASTNode> &stmts, DeclContext *parentDC,
+                     EnumDecl *enumDecl, VarDecl *enumVarDecl,
+                     AbstractFunctionDecl *funcDecl, const char *indexName);
+
+  static Pattern *enumElementPayloadSubpattern(
+      EnumElementDecl *enumElementDecl, char varPrefix, DeclContext *varContext,
+      SmallVectorImpl<VarDecl *> &boundVars, bool useLabels = false);
+
+  /// Creates a synthesized case statement that has the following structure:
+  ///
+  ///     case .<elt>, ..., .<elt>:
+  ///       _diagnoseUnavailableCodeReached()
+  ///
+  /// The number of \c .<elt> matches is equal to \p subPatternCount.
+  static CaseStmt *unavailableEnumElementCaseStmt(
+      Type enumType, EnumElementDecl *enumElementDecl, DeclContext *parentDC,
+      unsigned subPatternCount = 1);
+
+  static VarDecl *indexedVarDecl(char prefixChar, int index, Type type,
+                                 DeclContext *varContext);
+};
+
+/// Determine whether any "memberwise" accessors, which walk through the
+/// stored properties of the given nominal type, require actor isolation
+/// because they involve mutable state.
+bool memberwiseAccessorsRequireActorIsolation(NominalTypeDecl *nominal);
+
+} // namespace swift
+
+#endif
diff --git a/lib/Sema/DerivedConformanceActor.cpp b/lib/Sema/DerivedConformance/DerivedConformanceActor.cpp
similarity index 96%
rename from lib/Sema/DerivedConformanceActor.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceActor.cpp
index 54f87f4ed165a..24066b7ddb8a0 100644
--- a/lib/Sema/DerivedConformanceActor.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceActor.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceActor.cpp --------------------------------------===//
+//===--- DerivedConformanceActor.cpp ----------------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2018 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2018 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -19,7 +19,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
-#include "DerivedConformances.h"
+#include "DerivedConformance.h"
 #include "TypeChecker.h"
 #include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/Decl.h"
@@ -147,8 +147,7 @@ static ValueDecl *deriveActor_unownedExecutor(DerivedConformance &derived) {
   property->getAttrs().add(new (ctx) SemanticsAttr(SEMANTICS_DEFAULT_ACTOR,
                                                    SourceLoc(), SourceRange(),
                                                    /*implicit*/ true));
-  property->getAttrs().add(
-      new (ctx) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true));
+  property->getAttrs().add(NonisolatedAttr::createImplicit(ctx));
 
   // Make the property implicitly final.
   property->getAttrs().add(new (ctx) FinalAttr(/*IsImplicit=*/true));
diff --git a/lib/Sema/DerivedConformanceAdditiveArithmetic.cpp b/lib/Sema/DerivedConformance/DerivedConformanceAdditiveArithmetic.cpp
similarity index 99%
rename from lib/Sema/DerivedConformanceAdditiveArithmetic.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceAdditiveArithmetic.cpp
index a02988e7313ed..8536399325c01 100644
--- a/lib/Sema/DerivedConformanceAdditiveArithmetic.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceAdditiveArithmetic.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceAdditiveArithmetic.cpp -------------------------===//
+//===--- DerivedConformanceAdditiveArithmetic.cpp ---------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2018 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2018 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -22,6 +22,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
+#include "DerivedConformance.h"
 #include "TypeChecker.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
@@ -33,7 +34,6 @@
 #include "swift/AST/Stmt.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
-#include "DerivedConformances.h"
 
 using namespace swift;
 
diff --git a/lib/Sema/DerivedConformanceCaseIterable.cpp b/lib/Sema/DerivedConformance/DerivedConformanceCaseIterable.cpp
similarity index 91%
rename from lib/Sema/DerivedConformanceCaseIterable.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceCaseIterable.cpp
index 532264cc9362d..625032b92cd1c 100644
--- a/lib/Sema/DerivedConformanceCaseIterable.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceCaseIterable.cpp
@@ -1,11 +1,12 @@
+//===--- DerivedConformanceCaseIterable.cpp ---------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2016 Apple Inc. and the Swift project authors
+// Copyright (c) 2018 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
-// See http://swift.org/LICENSE.txt for license information
-// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//
 //
@@ -13,13 +14,13 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "DerivedConformance.h"
 #include "TypeChecker.h"
 #include "swift/AST/Decl.h"
-#include "swift/AST/Stmt.h"
 #include "swift/AST/Expr.h"
+#include "swift/AST/Stmt.h"
 #include "swift/AST/Types.h"
 #include "llvm/Support/raw_ostream.h"
-#include "DerivedConformances.h"
 
 using namespace swift;
 
@@ -104,8 +105,7 @@ ValueDecl *DerivedConformance::deriveCaseIterable(ValueDecl *requirement) {
       SynthesizedIntroducer::Var, Context.Id_allCases, returnTy,
       /*isStatic=*/true, /*isFinal=*/true);
 
-  propDecl->getAttrs().add(
-              new (C) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true));
+  propDecl->getAttrs().add(NonisolatedAttr::createImplicit(C));
 
   // Define the getter.
   auto *getterDecl = addGetterToReadOnlyDerivedProperty(propDecl);
diff --git a/lib/Sema/DerivedConformanceCodable.cpp b/lib/Sema/DerivedConformance/DerivedConformanceCodable.cpp
similarity index 97%
rename from lib/Sema/DerivedConformanceCodable.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceCodable.cpp
index 291e60ac276f4..723df50239c74 100644
--- a/lib/Sema/DerivedConformanceCodable.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceCodable.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceCodable.cpp - Derived Codable ------------------===//
+//===--- DerivedConformanceCodable.cpp --------------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -16,8 +16,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
+#include "DerivedConformance.h"
 #include "TypeChecker.h"
-#include "llvm/ADT/STLExtras.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/Expr.h"
@@ -28,7 +28,7 @@
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/StringExtras.h"
-#include "DerivedConformances.h"
+#include "llvm/ADT/STLExtras.h"
 
 using namespace swift;
 
@@ -760,10 +760,20 @@ lookupVarDeclForCodingKeysCase(DeclContext *conformanceDC,
   llvm_unreachable("Should have found at least 1 var decl");
 }
 
-static TryExpr *createEncodeCall(ASTContext &C, Type codingKeysType,
-                                 EnumElementDecl *codingKey,
-                                 Expr *containerExpr, Expr *varExpr,
-                                 bool useIfPresentVariant) {
+/// If strict memory safety checking is enabled, wrap the expression in an
+/// implicit "unsafe".
+static Expr *wrapInUnsafeIfNeeded(ASTContext &ctx, Expr *expr) {
+  if (ctx.LangOpts.hasFeature(Feature::StrictMemorySafety,
+                              /*allowMigration=*/true))
+    return UnsafeExpr::createImplicit(ctx, expr->getStartLoc(), expr);
+
+  return expr;
+}
+
+static Expr *createEncodeCall(ASTContext &C, Type codingKeysType,
+                              EnumElementDecl *codingKey,
+                              Expr *containerExpr, Expr *varExpr,
+                              bool useIfPresentVariant) {
   // CodingKeys.x
   auto *metaTyRef = TypeExpr::createImplicit(codingKeysType, C);
   auto *keyExpr = new (C) MemberRefExpr(metaTyRef, SourceLoc(), codingKey,
@@ -782,7 +792,7 @@ static TryExpr *createEncodeCall(ASTContext &C, Type codingKeysType,
   // try container.encode(x, forKey: CodingKeys.x)
   auto *tryExpr = new (C) TryExpr(SourceLoc(), callExpr, Type(),
                                   /*Implicit=*/true);
-  return tryExpr;
+  return wrapInUnsafeIfNeeded(C, tryExpr);
 }
 
 /// Synthesizes the body for `func encode(to encoder: Encoder) throws`.
@@ -917,7 +927,7 @@ deriveBodyEncodable_encode(AbstractFunctionDecl *encodeDecl, void *) {
     // try super.encode(to: container.superEncoder())
     auto *tryExpr = new (C) TryExpr(SourceLoc(), callExpr, Type(),
                                     /*Implicit=*/true);
-    statements.push_back(tryExpr);
+    statements.push_back(wrapInUnsafeIfNeeded(C, tryExpr));
   }
 
   auto *body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc(),
@@ -936,27 +946,10 @@ createEnumSwitch(ASTContext &C, DeclContext *DC, Expr *expr, EnumDecl *enumDecl,
     // .<elt>(let a0, let a1, ...)
     SmallVector<VarDecl *, 3> payloadVars;
     Pattern *subpattern = nullptr;
-    std::optional<MutableArrayRef<VarDecl *>> caseBodyVarDecls;
 
     if (createSubpattern) {
       subpattern = DerivedConformance::enumElementPayloadSubpattern(
           elt, 'a', DC, payloadVars, /* useLabels */ true);
-
-      auto hasBoundDecls = !payloadVars.empty();
-      if (hasBoundDecls) {
-        // We allocated a direct copy of our var decls for the case
-        // body.
-        auto copy = C.Allocate<VarDecl *>(payloadVars.size());
-        for (unsigned i : indices(payloadVars)) {
-          auto *vOld = payloadVars[i];
-          auto *vNew = new (C) VarDecl(
-              /*IsStatic*/ false, vOld->getIntroducer(), vOld->getNameLoc(),
-              vOld->getName(), vOld->getDeclContext());
-          vNew->setImplicit();
-          copy[i] = vNew;
-        }
-        caseBodyVarDecls.emplace(copy);
-      }
     }
 
     // CodingKeys.x
@@ -975,11 +968,8 @@ createEnumSwitch(ASTContext &C, DeclContext *DC, Expr *expr, EnumDecl *enumDecl,
                                                      subpattern, DC);
 
       auto labelItem = CaseLabelItem(pat);
-      auto stmt =
-          CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(), labelItem,
-                           SourceLoc(), SourceLoc(), caseBody,
-                           /*case body vardecls*/
-                           createSubpattern ? caseBodyVarDecls : std::nullopt);
+      auto stmt = CaseStmt::createImplicit(C, CaseParentKind::Switch, labelItem,
+                                           caseBody);
       cases.push_back(stmt);
     }
   }
@@ -1100,8 +1090,10 @@ deriveBodyEncodable_enum_encode(AbstractFunctionDecl *encodeDecl, void *) {
 
   // generate: switch self { }
   auto enumRef =
-      new (C) DeclRefExpr(ConcreteDeclRef(selfRef), DeclNameLoc(),
-                          /*implicit*/ true, AccessSemantics::Ordinary);
+      wrapInUnsafeIfNeeded(
+        C,
+        new (C) DeclRefExpr(ConcreteDeclRef(selfRef), DeclNameLoc(),
+                            /*implicit*/ true, AccessSemantics::Ordinary));
   auto switchStmt = createEnumSwitch(
       C, funcDC, enumRef, enumDecl, codingKeysEnum,
       /*createSubpattern*/ true,
@@ -1264,11 +1256,11 @@ static FuncDecl *deriveEncodable_encode(DerivedConformance &derived) {
   return encodeDecl;
 }
 
-static TryExpr *createDecodeCall(ASTContext &C, Type resultType,
-                                 Type codingKeysType,
-                                 EnumElementDecl *codingKey,
-                                 Expr *containerExpr,
-                                 bool useIfPresentVariant) {
+static Expr *createDecodeCall(ASTContext &C, Type resultType,
+                              Type codingKeysType,
+                              EnumElementDecl *codingKey,
+                              Expr *containerExpr,
+                              bool useIfPresentVariant) {
   auto methodName = useIfPresentVariant ? C.Id_decodeIfPresent : C.Id_decode;
 
   // Type.self
@@ -1458,7 +1450,7 @@ deriveBodyDecodable_init(AbstractFunctionDecl *initDecl, void *) {
                                                         varDecl->getName());
       auto *assignExpr = new (C) AssignExpr(varExpr, SourceLoc(), tryExpr,
                                             /*Implicit=*/true);
-      statements.push_back(assignExpr);
+      statements.push_back(wrapInUnsafeIfNeeded(C, assignExpr));
     }
   }
 
@@ -1494,7 +1486,7 @@ deriveBodyDecodable_init(AbstractFunctionDecl *initDecl, void *) {
         // try super.init(from: container.superDecoder())
         auto *tryExpr = new (C) TryExpr(SourceLoc(), callExpr, Type(),
                                         /*Implicit=*/true);
-        statements.push_back(tryExpr);
+        statements.push_back(wrapInUnsafeIfNeeded(C, tryExpr));
       } else {
         // The explicit constructor name is a compound name taking no arguments.
         DeclName initName(C, DeclBaseName::createConstructor(),
@@ -1526,7 +1518,7 @@ deriveBodyDecodable_init(AbstractFunctionDecl *initDecl, void *) {
           callExpr = new (C) TryExpr(SourceLoc(), callExpr, Type(),
                                      /*Implicit=*/true);
 
-        statements.push_back(callExpr);
+        statements.push_back(wrapInUnsafeIfNeeded(C, callExpr));
       }
     }
   }
@@ -1815,7 +1807,7 @@ deriveBodyDecodable_enum_init(AbstractFunctionDecl *initDecl, void *) {
                 new (C) AssignExpr(selfRef, SourceLoc(), selfCaseExpr,
                                    /*Implicit=*/true);
 
-            caseStatements.push_back(assignExpr);
+            caseStatements.push_back(wrapInUnsafeIfNeeded(C, assignExpr));
           } else {
             // Foo.bar(x:)
             SmallVector<Identifier, 3> scratch;
@@ -1833,7 +1825,7 @@ deriveBodyDecodable_enum_init(AbstractFunctionDecl *initDecl, void *) {
                 new (C) AssignExpr(selfRef, SourceLoc(), caseCallExpr,
                                    /*Implicit=*/true);
 
-            caseStatements.push_back(assignExpr);
+            caseStatements.push_back(wrapInUnsafeIfNeeded(C, assignExpr));
           }
 
           auto body =
diff --git a/lib/Sema/DerivedConformanceCodingKey.cpp b/lib/Sema/DerivedConformance/DerivedConformanceCodingKey.cpp
similarity index 94%
rename from lib/Sema/DerivedConformanceCodingKey.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceCodingKey.cpp
index 879bf0f03d005..ecbce38ca3032 100644
--- a/lib/Sema/DerivedConformanceCodingKey.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceCodingKey.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceCodingKey.cpp - Derived CodingKey --------------===//
+//===--- DerivedConformanceCodingKey.cpp ------------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,6 +15,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "DerivedConformance.h"
 #include "TypeChecker.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/Expr.h"
@@ -22,7 +23,6 @@
 #include "swift/AST/Pattern.h"
 #include "swift/AST/Stmt.h"
 #include "swift/AST/Types.h"
-#include "DerivedConformances.h"
 
 using namespace swift;
 
@@ -222,10 +222,8 @@ deriveBodyCodingKey_enum_stringValue(AbstractFunctionDecl *strValDecl, void *) {
       auto *returnStmt = ReturnStmt::createImplicit(C, caseValue);
       auto *caseBody = BraceStmt::create(C, SourceLoc(), ASTNode(returnStmt),
                                          SourceLoc());
-      cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                       labelItem, SourceLoc(), SourceLoc(),
-                                       caseBody,
-                                       /*case body var decls*/ std::nullopt));
+      cases.push_back(CaseStmt::createImplicit(C, CaseParentKind::Switch,
+                                               labelItem, caseBody));
     }
 
     auto *selfRef = DerivedConformance::createSelfDeclRef(strValDecl);
@@ -292,9 +290,8 @@ deriveBodyCodingKey_init_stringValue(AbstractFunctionDecl *initDecl, void *) {
 
     auto *body = BraceStmt::create(C, SourceLoc(), ASTNode(assignment),
                                    SourceLoc());
-    cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                     labelItem, SourceLoc(), SourceLoc(), body,
-                                     /*case body var decls*/ std::nullopt));
+    cases.push_back(
+        CaseStmt::createImplicit(C, CaseParentKind::Switch, labelItem, body));
   }
 
   auto *anyPat = AnyPattern::createImplicit(C);
@@ -303,10 +300,8 @@ deriveBodyCodingKey_init_stringValue(AbstractFunctionDecl *initDecl, void *) {
   auto *dfltReturnStmt = new (C) FailStmt(SourceLoc(), SourceLoc());
   auto *dfltBody = BraceStmt::create(C, SourceLoc(), ASTNode(dfltReturnStmt),
                                      SourceLoc());
-  cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                   dfltLabelItem, SourceLoc(), SourceLoc(),
-                                   dfltBody,
-                                   /*case body var decls*/ std::nullopt));
+  cases.push_back(CaseStmt::createImplicit(C, CaseParentKind::Switch,
+                                           dfltLabelItem, dfltBody));
 
   auto *stringValueDecl = initDecl->getParameters()->get(0);
   auto *stringValueRef = new (C) DeclRefExpr(stringValueDecl, DeclNameLoc(),
diff --git a/lib/Sema/DerivedConformanceComparable.cpp b/lib/Sema/DerivedConformance/DerivedConformanceComparable.cpp
similarity index 90%
rename from lib/Sema/DerivedConformanceComparable.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceComparable.cpp
index 6269fc2f0a0ad..01287cd0e2bdc 100644
--- a/lib/Sema/DerivedConformanceComparable.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceComparable.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceComparable.cpp - Derived Comparable -===//
+//===--- DerivedConformanceComparable.cpp -----------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,25 +11,26 @@
 //===----------------------------------------------------------------------===//
 //
 //  This file implements implicit derivation of the Comparable protocol.
-//  (Most of this code is similar to code in `DerivedConformanceEquatableHashable.cpp`)
+//  (Most of this code is similar to code in
+//  `DerivedConformanceEquatableHashable.cpp`)
 //
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
+#include "DerivedConformance.h"
 #include "TypeChecker.h"
 #include "swift/AST/Decl.h"
-#include "swift/AST/Stmt.h"
 #include "swift/AST/Expr.h"
 #include "swift/AST/Module.h"
-#include "swift/AST/Pattern.h"
 #include "swift/AST/ParameterList.h"
+#include "swift/AST/Pattern.h"
 #include "swift/AST/ProtocolConformance.h"
+#include "swift/AST/Stmt.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/raw_ostream.h"
-#include "DerivedConformances.h"
 
 using namespace swift;
 
@@ -126,23 +127,6 @@ deriveBodyComparable_enum_hasAssociatedValues_lt(AbstractFunctionDecl *ltDecl, v
     auto *rhsElemPat = EnumElementPattern::createImplicit(
         enumType, elt, rhsSubpattern, /*DC*/ ltDecl);
 
-    auto hasBoundDecls = !lhsPayloadVars.empty();
-    std::optional<MutableArrayRef<VarDecl *>> caseBodyVarDecls;
-    if (hasBoundDecls) {
-      // We allocated a direct copy of our lhs var decls for the case
-      // body.
-      auto copy = C.Allocate<VarDecl *>(lhsPayloadVars.size());
-      for (unsigned i : indices(lhsPayloadVars)) {
-        auto *vOld = lhsPayloadVars[i];
-        auto *vNew = new (C) VarDecl(
-            /*IsStatic*/ false, vOld->getIntroducer(),
-            vOld->getNameLoc(), vOld->getName(), vOld->getDeclContext());
-        vNew->setImplicit();
-        copy[i] = vNew;
-      }
-      caseBodyVarDecls.emplace(copy);
-    }
-
     // case (.<elt>(let l0, let l1, ...), .<elt>(let r0, let r1, ...))
     auto caseTuplePattern = TuplePattern::createImplicit(C, {
       TuplePatternElt(lhsElemPat), TuplePatternElt(rhsElemPat) });
@@ -176,9 +160,8 @@ deriveBodyComparable_enum_hasAssociatedValues_lt(AbstractFunctionDecl *ltDecl, v
 
     auto body = BraceStmt::create(C, SourceLoc(), statementsInCase,
                                   SourceLoc());
-    cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                     labelItem, SourceLoc(), SourceLoc(), body,
-                                     caseBodyVarDecls));
+    cases.push_back(
+        CaseStmt::createImplicit(C, CaseParentKind::Switch, labelItem, body));
   }
 
   // default: result = <enum index>(lhs) < <enum index>(rhs)
@@ -189,10 +172,8 @@ deriveBodyComparable_enum_hasAssociatedValues_lt(AbstractFunctionDecl *ltDecl, v
     auto defaultPattern = AnyPattern::createImplicit(C);
     auto defaultItem = CaseLabelItem::getDefault(defaultPattern);
     auto body = deriveBodyComparable_enum_noAssociatedValues_lt(ltDecl, nullptr).first;
-    cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                     defaultItem, SourceLoc(), SourceLoc(),
-                                     body,
-                                     /*case body var decls*/ std::nullopt));
+    cases.push_back(
+        CaseStmt::createImplicit(C, CaseParentKind::Switch, defaultItem, body));
   }
 
   // switch (a, b) { <case statements> }
diff --git a/lib/Sema/DerivedConformanceDifferentiable.cpp b/lib/Sema/DerivedConformance/DerivedConformanceDifferentiable.cpp
similarity index 98%
rename from lib/Sema/DerivedConformanceDifferentiable.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceDifferentiable.cpp
index e3542b9528ac1..58c317a61aa6f 100644
--- a/lib/Sema/DerivedConformanceDifferentiable.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceDifferentiable.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceDifferentiable.cpp - Derived Differentiable ----===//
+//===--- DerivedConformanceDifferentiable.cpp -------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2019 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2019 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -16,9 +16,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
-#include "TypeChecker.h"
+#include "DerivedConformance.h"
 #include "TypeCheckType.h"
-#include "llvm/ADT/SmallPtrSet.h"
+#include "TypeChecker.h"
 #include "swift/AST/AutoDiff.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
@@ -32,7 +32,7 @@
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
-#include "DerivedConformances.h"
+#include "llvm/ADT/SmallPtrSet.h"
 
 using namespace swift;
 
@@ -50,10 +50,9 @@ static bool canInvokeMoveByOnProperty(
     return true;
   // When the property is a `let`, the only case that would be supported is when
   // it has a `move(by:)` protocol requirement witness that is non-mutating.
-  auto interfaceType = vd->getInterfaceType();
   auto &C = vd->getASTContext();
   auto witness = diffableConformance.getWitnessByName(
-      interfaceType, DeclName(C, C.Id_move, {C.Id_by}));
+      DeclName(C, C.Id_move, {C.Id_by}));
   if (!witness)
     return false;
   auto *decl = cast<FuncDecl>(witness.getDecl());
@@ -121,7 +120,7 @@ static Type getTangentVectorInterfaceType(Type contextualType,
   assert(conf && "Contextual type must conform to `Differentiable`");
   if (!conf)
     return nullptr;
-  auto tanType = conf.getTypeWitnessByName(contextualType, C.Id_TangentVector);
+  auto tanType = conf.getTypeWitnessByName(C.Id_TangentVector);
   return tanType->hasArchetype() ? tanType->mapTypeOutOfContext() : tanType;
 }
 
@@ -150,7 +149,7 @@ static bool canDeriveTangentVectorAsSelf(NominalTypeDecl *nominal,
     auto conf = checkConformance(fieldType, diffableProto);
     if (!conf)
       return false;
-    auto tangentType = conf.getTypeWitnessByName(fieldType, C.Id_TangentVector);
+    auto tangentType = conf.getTypeWitnessByName(C.Id_TangentVector);
     if (!fieldType->isEqual(tangentType))
       return false;
   }
diff --git a/lib/Sema/DerivedConformanceDistributedActor.cpp b/lib/Sema/DerivedConformance/DerivedConformanceDistributedActor.cpp
similarity index 96%
rename from lib/Sema/DerivedConformanceDistributedActor.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceDistributedActor.cpp
index 385074f80b1ad..c5bd8b1cf1d4b 100644
--- a/lib/Sema/DerivedConformanceDistributedActor.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceDistributedActor.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceActor.cpp - Derived Actor Conformance ----------===//
+//===--- DerivedConformanceActor.cpp ----------------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,7 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
-#include "DerivedConformances.h"
+#include "DerivedConformance.h"
 #include "TypeCheckDistributed.h"
 #include "TypeChecker.h"
 #include "swift/AST/AvailabilityInference.h"
@@ -171,7 +171,7 @@ deriveBodyDistributed_doInvokeOnReturn(AbstractFunctionDecl *afd, void *arg) {
                          new (C) DeclRefExpr(ConcreteDeclRef(returnTypeParam),
                                              dloc, implicit))}));
 
-    if (C.LangOpts.hasFeature(Feature::StrictMemorySafety))
+    if (C.LangOpts.hasFeature(Feature::StrictMemorySafety, /*allowMigration=*/true))
       resultLoadCall = new (C) UnsafeExpr(sloc, resultLoadCall, Type(), true);
 
     auto resultPattern = NamedPattern::createImplicit(C, resultVar);
@@ -332,17 +332,24 @@ deriveBodyDistributed_invokeHandlerOnReturn(AbstractFunctionDecl *afd,
     metatypeVar->setImplicit();
     metatypeVar->setSynthesized();
 
+    // If the SerializationRequirement requires it, we need to emit a cast:
     // metatype as! <<concrete SerializationRequirement.Type>>
+    bool serializationRequirementIsAny =
+      serializationRequirementMetaTypeTy->getMetatypeInstanceType()->isEqual(
+            C.getAnyExistentialType());
+
     auto metatypeRef =
         new (C) DeclRefExpr(ConcreteDeclRef(metatypeParam), dloc, implicit);
-    auto metatypeSRCastExpr = ForcedCheckedCastExpr::createImplicit(
-        C, metatypeRef, serializationRequirementMetaTypeTy);
-
     auto metatypePattern = NamedPattern::createImplicit(C, metatypeVar);
-    auto metatypePB = PatternBindingDecl::createImplicit(
-        C, swift::StaticSpellingKind::None, metatypePattern,
-        /*expr=*/metatypeSRCastExpr, func);
 
+    PatternBindingDecl *metatypePB = serializationRequirementIsAny ?
+      PatternBindingDecl::createImplicit(
+          C, swift::StaticSpellingKind::None, metatypePattern,
+          /*expr=*/metatypeRef, func) :
+      PatternBindingDecl::createImplicit(
+          C, swift::StaticSpellingKind::None, metatypePattern,
+          /*expr=*/ForcedCheckedCastExpr::createImplicit(
+          C, metatypeRef, serializationRequirementMetaTypeTy), func);
     stmts.push_back(metatypePB);
     stmts.push_back(metatypeVar);
   }
@@ -399,7 +406,6 @@ static FuncDecl *deriveDistributedActorSystem_invokeHandlerOnReturn(
   auto system = derived.Nominal;
   auto &C = system->getASTContext();
 
-  // auto serializationRequirementType = getDistributedActorSystemType(decl);
   auto resultHandlerType = getDistributedActorSystemResultHandlerType(system);
   auto unsafeRawPointerType = C.getUnsafeRawPointerType();
   auto anyTypeType = ExistentialMetatypeType::get(C.TheAnyType); // Any.Type
@@ -436,7 +442,7 @@ static FuncDecl *deriveDistributedActorSystem_invokeHandlerOnReturn(
                                /*throws=*/true,
                                /*ThrownType=*/Type(),
                                /*genericParams=*/nullptr, params,
-                               /*returnType*/ TupleType::getEmpty(C), system);
+                               /*returnType=*/TupleType::getEmpty(C), system);
   funcDecl->setSynthesized(true);
   funcDecl->copyFormalAccessFrom(system, /*sourceIsParentContext=*/true);
   funcDecl->setBodySynthesizer(deriveBodyDistributed_invokeHandlerOnReturn);
@@ -465,8 +471,7 @@ static ValueDecl *deriveDistributedActor_id(DerivedConformance &derived) {
       /*isStatic=*/false, /*isFinal=*/true);
 
   // mark as nonisolated, allowing access to it from everywhere
-  propDecl->getAttrs().add(
-      new (C) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true));
+  propDecl->getAttrs().add(NonisolatedAttr::createImplicit(C));
 
   derived.addMemberToConformanceContext(pbDecl, /*insertAtHead=*/true);
   derived.addMemberToConformanceContext(propDecl, /*insertAtHead=*/true);
@@ -496,8 +501,7 @@ static ValueDecl *deriveDistributedActor_actorSystem(
       propertyType, /*isStatic=*/false, /*isFinal=*/true);
 
   // mark as nonisolated, allowing access to it from everywhere
-  propDecl->getAttrs().add(
-      new (C) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true));
+  propDecl->getAttrs().add(NonisolatedAttr::createImplicit(C));
 
   // IMPORTANT: `id` MUST be the first field of a distributed actor, and
   // `actorSystem` MUST be the second field, because for a remote instance
@@ -795,8 +799,7 @@ static ValueDecl *deriveDistributedActor_unownedExecutor(DerivedConformance &der
   property->getAttrs().add(new (ctx) SemanticsAttr(SEMANTICS_DEFAULT_ACTOR,
                                                    SourceLoc(), SourceRange(),
                                                    /*implicit*/ true));
-  property->getAttrs().add(
-      new (ctx) NonisolatedAttr(/*unsafe=*/false, /*implicit=*/true));
+  property->getAttrs().add(NonisolatedAttr::createImplicit(ctx));
 
   // Make the property implicitly final.
   property->getAttrs().add(new (ctx) FinalAttr(/*IsImplicit=*/true));
diff --git a/lib/Sema/DerivedConformanceEquatableHashable.cpp b/lib/Sema/DerivedConformance/DerivedConformanceEquatableHashable.cpp
similarity index 94%
rename from lib/Sema/DerivedConformanceEquatableHashable.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceEquatableHashable.cpp
index 6240036daebe8..b1cd116446201 100644
--- a/lib/Sema/DerivedConformanceEquatableHashable.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceEquatableHashable.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceEquatableHashable.cpp - Derived Equatable & co -===//
+//===--- DerivedConformanceEquatableHashable.cpp ----------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,25 +11,25 @@
 //===----------------------------------------------------------------------===//
 //
 //  This file implements implicit derivation of the Equatable and Hashable
-//  protocols. 
+//  protocols.
 //
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
+#include "DerivedConformance.h"
 #include "TypeChecker.h"
 #include "swift/AST/Decl.h"
-#include "swift/AST/Stmt.h"
 #include "swift/AST/Expr.h"
 #include "swift/AST/Module.h"
-#include "swift/AST/Pattern.h"
 #include "swift/AST/ParameterList.h"
+#include "swift/AST/Pattern.h"
 #include "swift/AST/ProtocolConformance.h"
+#include "swift/AST/Stmt.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/raw_ostream.h"
-#include "DerivedConformances.h"
 
 using namespace swift;
 
@@ -193,23 +193,6 @@ deriveBodyEquatable_enum_hasAssociatedValues_eq(AbstractFunctionDecl *eqDecl,
     auto *rhsElemPat = EnumElementPattern::createImplicit(
         enumType, elt, rhsSubpattern, /*DC*/ eqDecl);
 
-    auto hasBoundDecls = !lhsPayloadVars.empty();
-    std::optional<MutableArrayRef<VarDecl *>> caseBodyVarDecls;
-    if (hasBoundDecls) {
-      // We allocated a direct copy of our lhs var decls for the case
-      // body.
-      auto copy = C.Allocate<VarDecl *>(lhsPayloadVars.size());
-      for (unsigned i : indices(lhsPayloadVars)) {
-        auto *vOld = lhsPayloadVars[i];
-        auto *vNew = new (C) VarDecl(
-            /*IsStatic*/ false, vOld->getIntroducer(),
-            vOld->getNameLoc(), vOld->getName(), vOld->getDeclContext());
-        vNew->setImplicit();
-        copy[i] = vNew;
-      }
-      caseBodyVarDecls.emplace(copy);
-    }
-
     // case (.<elt>(let l0, let l1, ...), .<elt>(let r0, let r1, ...))
     auto caseTuplePattern = TuplePattern::createImplicit(C, {
       TuplePatternElt(lhsElemPat), TuplePatternElt(rhsElemPat) });
@@ -244,9 +227,8 @@ deriveBodyEquatable_enum_hasAssociatedValues_eq(AbstractFunctionDecl *eqDecl,
 
     auto body = BraceStmt::create(C, SourceLoc(), statementsInCase,
                                   SourceLoc());
-    cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                     labelItem, SourceLoc(), SourceLoc(), body,
-                                     caseBodyVarDecls));
+    cases.push_back(
+        CaseStmt::createImplicit(C, CaseParentKind::Switch, labelItem, body));
   }
 
   // default: result = false
@@ -261,10 +243,8 @@ deriveBodyEquatable_enum_hasAssociatedValues_eq(AbstractFunctionDecl *eqDecl,
     auto *returnStmt = ReturnStmt::createImplicit(C, falseExpr);
     auto body = BraceStmt::create(C, SourceLoc(), ASTNode(returnStmt),
                                   SourceLoc());
-    cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                     defaultItem, SourceLoc(), SourceLoc(),
-                                     body,
-                                     /*case body var decls*/ std::nullopt));
+    cases.push_back(
+        CaseStmt::createImplicit(C, CaseParentKind::Switch, defaultItem, body));
   }
 
   // switch (a, b) { <case statements> }
@@ -394,10 +374,12 @@ deriveEquatable_eq(
   auto boolTy = C.getBoolType();
 
   Identifier generatedIdentifier;
+  bool isDerivedEnumEquals = false;
   if (parentDC->getParentModule()->isResilient()) {
     generatedIdentifier = C.Id_EqualsOperator;
   } else if (selfIfaceTy->getEnumOrBoundGenericEnum()) {
     generatedIdentifier = C.Id_derived_enum_equals;
+    isDerivedEnumEquals = true;
   } else {
     assert(selfIfaceTy->getStructOrBoundGenericStruct());
     generatedIdentifier = C.Id_derived_struct_equals;
@@ -411,6 +393,9 @@ deriveEquatable_eq(
       /*GenericParams=*/nullptr, params, boolTy, parentDC);
   eqDecl->setUserAccessible(false);
   eqDecl->setSynthesized();
+  if (isDerivedEnumEquals) {
+    eqDecl->getAttrs().add(new (C) SemanticsAttr("derived_enum_equals", SourceLoc(), SourceRange(), /*Implicit=*/true));
+  }
 
   // Add the @_implements(Equatable, ==(_:_:)) attribute
   if (generatedIdentifier != C.Id_EqualsOperator) {
@@ -555,8 +540,7 @@ deriveHashable_hashInto(
   // The derived hash(into:) for an actor must be non-isolated.
   if (!addNonIsolatedToSynthesized(derived, hashDecl) &&
       derived.Nominal->isActor())
-    hashDecl->getAttrs().add(
-        new (C) NonisolatedAttr(/*unsafe*/ false, /*implicit*/ true));
+    hashDecl->getAttrs().add(NonisolatedAttr::createImplicit(C));
 
   derived.addMembersToConformanceContext({hashDecl});
 
@@ -731,26 +715,9 @@ deriveBodyHashable_enum_hasAssociatedValues_hashInto(
       statements.emplace_back(ASTNode(combineExpr));
     }
 
-    auto hasBoundDecls = !payloadVars.empty();
-    std::optional<MutableArrayRef<VarDecl *>> caseBodyVarDecls;
-    if (hasBoundDecls) {
-      auto copy = C.Allocate<VarDecl *>(payloadVars.size());
-      for (unsigned i : indices(payloadVars)) {
-        auto *vOld = payloadVars[i];
-        auto *vNew = new (C) VarDecl(
-            /*IsStatic*/ false, vOld->getIntroducer(),
-            vOld->getNameLoc(), vOld->getName(), vOld->getDeclContext());
-        vNew->setImplicit();
-        copy[i] = vNew;
-      }
-      caseBodyVarDecls.emplace(copy);
-    }
-
     auto body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc());
-    cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                     labelItem, SourceLoc(), SourceLoc(), body,
-                                     caseBodyVarDecls,
-                                     /*implicit*/ true));
+    cases.push_back(
+        CaseStmt::createImplicit(C, CaseParentKind::Switch, labelItem, body));
   }
 
   // generate: switch enumVar { }
@@ -912,8 +879,7 @@ static ValueDecl *deriveHashable_hashValue(DerivedConformance &derived) {
   // The derived hashValue of an actor must be nonisolated.
   if (!addNonIsolatedToSynthesized(derived, hashValueDecl) &&
       derived.Nominal->isActor())
-    hashValueDecl->getAttrs().add(
-        new (C) NonisolatedAttr(/*unsafe*/ false, /*implicit*/ true));
+    hashValueDecl->getAttrs().add(NonisolatedAttr::createImplicit(C));
 
   Pattern *hashValuePat =
       NamedPattern::createImplicit(C, hashValueDecl, intType);
diff --git a/lib/Sema/DerivedConformanceError.cpp b/lib/Sema/DerivedConformance/DerivedConformanceError.cpp
similarity index 96%
rename from lib/Sema/DerivedConformanceError.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceError.cpp
index 56fc69a73aeb5..82d8465900283 100644
--- a/lib/Sema/DerivedConformanceError.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceError.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceError.cpp - Derived Error ----------------------===//
+//===--- DerivedConformanceError.cpp ----------------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -16,14 +16,14 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
+#include "DerivedConformance.h"
 #include "TypeChecker.h"
-#include "DerivedConformances.h"
 #include "swift/AST/Decl.h"
-#include "swift/AST/Stmt.h"
 #include "swift/AST/Expr.h"
 #include "swift/AST/Module.h"
-#include "swift/AST/Types.h"
+#include "swift/AST/Stmt.h"
 #include "swift/AST/SwiftNameTranslation.h"
+#include "swift/AST/Types.h"
 
 using namespace swift;
 using namespace swift::objc_translation;
diff --git a/lib/Sema/DerivedConformanceRawRepresentable.cpp b/lib/Sema/DerivedConformance/DerivedConformanceRawRepresentable.cpp
similarity index 93%
rename from lib/Sema/DerivedConformanceRawRepresentable.cpp
rename to lib/Sema/DerivedConformance/DerivedConformanceRawRepresentable.cpp
index 4f64bed1c8344..b8a3ec8eefc06 100644
--- a/lib/Sema/DerivedConformanceRawRepresentable.cpp
+++ b/lib/Sema/DerivedConformance/DerivedConformanceRawRepresentable.cpp
@@ -1,8 +1,8 @@
-//===--- DerivedConformanceRawRepresentable.cpp - Derived RawRepresentable ===//
+//===--- DerivedConformanceRawRepresentable.cpp -----------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -16,7 +16,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
-#include "DerivedConformances.h"
+#include "DerivedConformance.h"
 #include "TypeCheckAvailability.h"
 #include "TypeCheckDecl.h"
 #include "TypeChecker.h"
@@ -105,7 +105,9 @@ deriveBodyRawRepresentable_raw(AbstractFunctionDecl *toRawDecl, void *) {
 
     auto *argList = ArgumentList::forImplicitCallTo(functionRef->getName(),
                                                     {selfRef, typeExpr}, C);
-    auto call = CallExpr::createImplicit(C, functionRef, argList);
+    Expr *call = CallExpr::createImplicit(C, functionRef, argList);
+    if (C.LangOpts.hasFeature(Feature::StrictMemorySafety, /*allowMigration=*/true))
+      call = UnsafeExpr::createImplicit(C, SourceLoc(), call);
     auto *returnStmt = ReturnStmt::createImplicit(C, call);
     auto body = BraceStmt::create(C, SourceLoc(), ASTNode(returnStmt),
                                   SourceLoc());
@@ -127,9 +129,8 @@ deriveBodyRawRepresentable_raw(AbstractFunctionDecl *toRawDecl, void *) {
     auto body = BraceStmt::create(C, SourceLoc(),
                                   ASTNode(returnStmt), SourceLoc());
 
-    cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                     labelItem, SourceLoc(), SourceLoc(), body,
-                                     /*case body var decls*/ std::nullopt));
+    cases.push_back(
+        CaseStmt::createImplicit(C, CaseParentKind::Switch, labelItem, body));
   }
 
   auto selfRef = DerivedConformance::createSelfDeclRef(toRawDecl);
@@ -201,9 +202,9 @@ struct RuntimeVersionCheck {
   /// fails, e.g. "guard #available(iOS 10, *) else { return nil }".
   Stmt *createEarlyReturnStmt(ASTContext &C) const {
     // platformSpec = "\(attr.platform) \(attr.introduced)"
+    auto domain = AvailabilityDomain::forPlatform(Platform);
     auto platformSpec = AvailabilitySpec::createForDomain(
-        C, AvailabilityDomain::forPlatform(Platform), SourceLoc(), Version,
-        SourceLoc());
+        C, domain, SourceLoc(), Version, SourceLoc());
 
     // wildcardSpec = "*"
     auto wildcardSpec = AvailabilitySpec::createWildcard(C, SourceLoc());
@@ -215,7 +216,8 @@ struct RuntimeVersionCheck {
 
     // This won't be filled in by TypeCheckAvailability because we have
     // invalid SourceLocs in this area of the AST.
-    availableInfo->setAvailableRange(getVersionRange());
+    availableInfo->setAvailabilityQuery(AvailabilityQuery::dynamic(
+        domain, AvailabilityRange(getVersionRange()), std::nullopt));
 
     // earlyReturnBody = "{ return nil }"
     auto earlyReturn = new (C) FailStmt(SourceLoc(), SourceLoc());
@@ -258,18 +260,16 @@ checkAvailability(const EnumElementDecl *elt,
   if (!constraint->isActiveForRuntimeQueries(C))
     return true;
 
-  auto domain = constraint->getDomain();
+  auto domainAndRange = constraint->getDomainAndRange(C);
 
   // Only platform version constraints are supported currently.
   // FIXME: [availability] Support non-platform domain availability checks
-  if (!domain.isPlatform())
+  if (!domainAndRange.getDomain().isPlatform())
     return true;
 
   // It's conditionally available; create a version constraint and return true.
-  auto range = constraint->getPotentiallyUnavailableRange(C);
-
-  ASSERT(range);
-  versionCheck.emplace(domain.getPlatformKind(), range->getRawMinimumVersion());
+  versionCheck.emplace(domainAndRange.getDomain().getPlatformKind(),
+                       domainAndRange.getRange().getRawMinimumVersion());
   return true;
 }
 
@@ -362,10 +362,8 @@ deriveBodyRawRepresentable_init(AbstractFunctionDecl *initDecl, void *) {
                                   stmts, SourceLoc());
 
     // cases.append("case \(litPat): \(body)")
-    cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                     CaseLabelItem(litPat), SourceLoc(),
-                                     SourceLoc(), body,
-                                     /*case body var decls*/ std::nullopt));
+    cases.push_back(CaseStmt::createImplicit(C, CaseParentKind::Switch,
+                                             CaseLabelItem(litPat), body));
     ++Idx;
   }
 
@@ -375,10 +373,8 @@ deriveBodyRawRepresentable_init(AbstractFunctionDecl *initDecl, void *) {
   auto dfltReturnStmt = new (C) FailStmt(SourceLoc(), SourceLoc());
   auto dfltBody = BraceStmt::create(C, SourceLoc(),
                                     ASTNode(dfltReturnStmt), SourceLoc());
-  cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                   dfltLabelItem, SourceLoc(), SourceLoc(),
-                                   dfltBody,
-                                   /*case body var decls*/ std::nullopt));
+  cases.push_back(CaseStmt::createImplicit(C, CaseParentKind::Switch,
+                                           dfltLabelItem, dfltBody));
 
   auto rawDecl = initDecl->getParameters()->get(0);
   auto rawRef = new (C) DeclRefExpr(rawDecl, DeclNameLoc(), /*implicit*/true);
diff --git a/lib/Sema/DerivedConformances.cpp b/lib/Sema/DerivedConformances.cpp
deleted file mode 100644
index c0e05b978a3ce..0000000000000
--- a/lib/Sema/DerivedConformances.cpp
+++ /dev/null
@@ -1,1004 +0,0 @@
-//===--- DerivedConformances.cpp - Derived conformance utilities ----------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-#include "TypeChecker.h"
-#include "TypeCheckConcurrency.h"
-#include "swift/AST/ASTPrinter.h"
-#include "swift/AST/ConformanceLookup.h"
-#include "swift/AST/Decl.h"
-#include "swift/AST/Stmt.h"
-#include "swift/AST/Expr.h"
-#include "swift/AST/Pattern.h"
-#include "swift/AST/ParameterList.h"
-#include "swift/AST/ProtocolConformance.h"
-#include "swift/AST/SourceFile.h"
-#include "swift/AST/Types.h"
-#include "swift/Basic/Assertions.h"
-#include "swift/ClangImporter/ClangModule.h"
-#include "DerivedConformances.h"
-
-using namespace swift;
-
-enum NonconformingMemberKind { AssociatedValue, StoredProperty };
-
-DerivedConformance::DerivedConformance(
-    const NormalProtocolConformance *conformance, NominalTypeDecl *nominal,
-    ProtocolDecl *protocol)
-    : Context(nominal->getASTContext()), Conformance(conformance),
-      Nominal(nominal), Protocol(protocol) {
-  auto *DC = Conformance->getDeclContext();
-  ConformanceDecl = DC->getInnermostDeclarationDeclContext();
-  assert(ConformanceDecl);
-  assert(DC->getSelfNominalTypeDecl() == nominal);
-}
-
-DeclContext *DerivedConformance::getConformanceContext() const {
-  return Conformance->getDeclContext();
-}
-
-ModuleDecl *DerivedConformance::getParentModule() const {
-  return getConformanceContext()->getParentModule();
-}
-
-void DerivedConformance::addMembersToConformanceContext(
-    ArrayRef<Decl *> children) {
-  auto IDC = cast<IterableDeclContext>(ConformanceDecl);
-  for (auto child : children)
-    IDC->addMember(child);
-}
-
-void DerivedConformance::addMemberToConformanceContext(
-    Decl *member, Decl *hint) {
-  auto IDC = cast<IterableDeclContext>(ConformanceDecl);
-  IDC->addMember(member, hint, /*insertAtHead=*/false);
-}
-
-void DerivedConformance::addMemberToConformanceContext(
-    Decl *member, bool insertAtHead) {
-  auto IDC = cast<IterableDeclContext>(ConformanceDecl);
-  IDC->addMember(member, /*hint=*/nullptr, insertAtHead);
-}
-
-Type DerivedConformance::getProtocolType() const {
-  return Protocol->getDeclaredInterfaceType();
-}
-
-bool DerivedConformance::derivesProtocolConformance(DeclContext *DC,
-                                                    NominalTypeDecl *Nominal,
-                                                    ProtocolDecl *Protocol) {
-  const auto derivableKind = Protocol->getKnownDerivableProtocolKind();
-  if (!derivableKind)
-    return false;
-
-  // When the necessary requirements are met, the conformance to OptionSet
-  // is serendipitously derived via memberwise initializer synthesis.
-  if (*derivableKind == KnownDerivableProtocolKind::OptionSet) {
-    return false;
-  }
-
-  if (*derivableKind == KnownDerivableProtocolKind::Hashable) {
-    // We can always complete a partial Hashable implementation, and we can
-    // synthesize a full Hashable implementation for structs and enums with
-    // Hashable components.
-    return canDeriveHashable(Nominal);
-  }
-
-  if (*derivableKind == KnownDerivableProtocolKind::Actor)
-    return canDeriveActor(DC, Nominal);
-
-  if (*derivableKind == KnownDerivableProtocolKind::Identifiable)
-    return canDeriveIdentifiable(Nominal, DC);
-  if (*derivableKind == KnownDerivableProtocolKind::DistributedActor)
-    return canDeriveDistributedActor(Nominal, DC);
-  if (*derivableKind == KnownDerivableProtocolKind::DistributedActorSystem)
-    return canDeriveDistributedActorSystem(Nominal, DC);
-
-  if (*derivableKind == KnownDerivableProtocolKind::AdditiveArithmetic)
-    return canDeriveAdditiveArithmetic(Nominal, DC);
-
-  // Eagerly return true here. Actual synthesis conditions are checked in
-  // `DerivedConformance::deriveDifferentiable`: they are complicated and depend
-  // on the requirement being derived.
-  if (*derivableKind == KnownDerivableProtocolKind::Differentiable)
-    return true;
-
-  if (*derivableKind == KnownDerivableProtocolKind::Encodable) {
-    return canDeriveEncodable(Nominal);
-  }
-
-  if (*derivableKind == KnownDerivableProtocolKind::Decodable) {
-    return canDeriveDecodable(Nominal);
-  }
-
-  if (auto *enumDecl = dyn_cast<EnumDecl>(Nominal)) {
-    switch (*derivableKind) {
-        // The presence of a raw type is an explicit declaration that
-        // the compiler should derive a RawRepresentable conformance.
-      case KnownDerivableProtocolKind::RawRepresentable:
-        return canDeriveRawRepresentable(DC, Nominal);
-
-        // Enums without associated values can implicitly derive Equatable
-        // conformance.
-      case KnownDerivableProtocolKind::Equatable:
-        return canDeriveEquatable(DC, Nominal);
-      
-      case KnownDerivableProtocolKind::Comparable:
-        return !enumDecl->hasPotentiallyUnavailableCaseValue()
-            && canDeriveComparable(DC, enumDecl); 
-
-        // "Simple" enums without availability attributes can explicitly derive
-        // a CaseIterable conformance.
-        //
-        // FIXME: Lift the availability restriction.
-      case KnownDerivableProtocolKind::CaseIterable:
-        return !enumDecl->hasPotentiallyUnavailableCaseValue()
-            && enumDecl->hasOnlyCasesWithoutAssociatedValues();
-
-        // @objc enums can explicitly derive their _BridgedNSError conformance.
-      case KnownDerivableProtocolKind::BridgedNSError:
-        return enumDecl->isObjC() && enumDecl->hasCases()
-            && enumDecl->hasOnlyCasesWithoutAssociatedValues();
-
-        // Enums without associated values and enums with a raw type of String
-        // or Int can explicitly derive CodingKey conformance.
-      case KnownDerivableProtocolKind::CodingKey: {
-        Type rawType = enumDecl->getRawType();
-        if (rawType) {
-          return rawType->isString() || rawType->isInt();
-        }
-
-        // hasOnlyCasesWithoutAssociatedValues will return true for empty enums;
-        // empty enums are allowed to conform as well.
-        return enumDecl->hasOnlyCasesWithoutAssociatedValues();
-      }
-
-      default:
-        return false;
-    }
-  } else if (isa<StructDecl>(Nominal)) {
-    switch (*derivableKind) {
-    case KnownDerivableProtocolKind::Equatable:
-      // Structs can explicitly derive Equatable conformance.
-      return canDeriveEquatable(DC, Nominal);
-    default:
-      return false;
-    }
-  }
-  return false;
-}
-
-SmallVector<VarDecl *, 3>
-DerivedConformance::storedPropertiesNotConformingToProtocol(
-    DeclContext *DC, StructDecl *theStruct, ProtocolDecl *protocol) {
-  auto storedProperties = theStruct->getStoredProperties();
-  SmallVector<VarDecl *, 3> nonconformingProperties;
-  for (auto propertyDecl : storedProperties) {
-    if (!propertyDecl->isUserAccessible())
-      continue;
-
-    auto type = propertyDecl->getValueInterfaceType();
-    if (!type)
-      nonconformingProperties.push_back(propertyDecl);
-
-    if (!checkConformance(DC->mapTypeIntoContext(type), protocol)) {
-      nonconformingProperties.push_back(propertyDecl);
-    }
-  }
-  return nonconformingProperties;
-}
-
-void DerivedConformance::tryDiagnoseFailedDerivation(DeclContext *DC,
-                                                     NominalTypeDecl *nominal,
-                                                     ProtocolDecl *protocol) {
-  auto knownProtocol = protocol->getKnownProtocolKind();
-  if (!knownProtocol)
-    return;
-  
-  if (*knownProtocol == KnownProtocolKind::Equatable) {
-    tryDiagnoseFailedEquatableDerivation(DC, nominal);
-  }
-
-  if (*knownProtocol == KnownProtocolKind::Hashable) {
-    tryDiagnoseFailedHashableDerivation(DC, nominal);
-  }
-
-  if (*knownProtocol == KnownProtocolKind::Comparable) {
-    tryDiagnoseFailedComparableDerivation(DC, nominal);
-  }
-
-  if (*knownProtocol == KnownProtocolKind::DistributedActor) {
-    tryDiagnoseFailedDistributedActorDerivation(DC, nominal);
-  }
-
-  if (*knownProtocol == KnownProtocolKind::DistributedActorSystem) {
-    tryDiagnoseFailedDistributedActorSystemDerivation(DC, nominal);
-  }
-}
-
-void DerivedConformance::diagnoseAnyNonConformingMemberTypes(
-    DeclContext *DC, NominalTypeDecl *nominal, ProtocolDecl *protocol) {
-  ASTContext &ctx = DC->getASTContext();
-
-  if (auto *enumDecl = dyn_cast<EnumDecl>(nominal)) {
-    auto nonconformingAssociatedTypes =
-        associatedValuesNotConformingToProtocol(DC, enumDecl, protocol);
-    for (auto *typeToDiagnose : nonconformingAssociatedTypes) {
-      SourceLoc reprLoc;
-      if (auto *repr = typeToDiagnose->getTypeRepr())
-        reprLoc = repr->getStartLoc();
-      ctx.Diags.diagnose(
-          reprLoc, diag::missing_member_type_conformance_prevents_synthesis,
-          NonconformingMemberKind::AssociatedValue,
-          typeToDiagnose->getInterfaceType(),
-          protocol->getDeclaredInterfaceType(),
-          nominal->getDeclaredInterfaceType());
-    }
-  }
-
-  if (auto *structDecl = dyn_cast<StructDecl>(nominal)) {
-    auto nonconformingStoredProperties =
-        storedPropertiesNotConformingToProtocol(DC, structDecl, protocol);
-    for (auto *propertyToDiagnose : nonconformingStoredProperties) {
-      ctx.Diags.diagnose(
-          propertyToDiagnose->getLoc(),
-          diag::missing_member_type_conformance_prevents_synthesis,
-          NonconformingMemberKind::StoredProperty,
-          propertyToDiagnose->getInterfaceType(),
-          protocol->getDeclaredInterfaceType(),
-          nominal->getDeclaredInterfaceType());
-    }
-  }
-}
-
-void DerivedConformance::diagnoseIfSynthesisUnsupportedForDecl(
-    NominalTypeDecl *nominal, ProtocolDecl *protocol) {
-  auto shouldDiagnose = false;
-
-  if (protocol->isSpecificProtocol(KnownProtocolKind::Equatable) ||
-      protocol->isSpecificProtocol(KnownProtocolKind::Hashable)) {
-    shouldDiagnose = isa<ClassDecl>(nominal);
-  }
-
-  if (protocol->isSpecificProtocol(KnownProtocolKind::Comparable)) {
-    shouldDiagnose = !isa<EnumDecl>(nominal);
-  }
-
-  if (shouldDiagnose) {
-    auto &ctx = nominal->getASTContext();
-    ctx.Diags.diagnose(
-        nominal->getLoc(), diag::automatic_protocol_synthesis_unsupported,
-        protocol->getName().str(), nominal->getDescriptiveKind());
-  }
-}
-
-ValueDecl *DerivedConformance::getDerivableRequirement(NominalTypeDecl *nominal,
-                                                       ValueDecl *requirement) {
-  // Note: whenever you update this function, also update
-  // deriveProtocolRequirement.
-  ASTContext &ctx = nominal->getASTContext();
-  const auto name = requirement->getName();
-
-  // Local function that retrieves the requirement with the same name as
-  // the provided requirement, but within the given known protocol.
-  auto getRequirement = [&](KnownProtocolKind kind) -> ValueDecl * {
-    // Dig out the protocol.
-    auto proto = ctx.getProtocol(kind);
-    if (!proto) return nullptr;
-
-    auto conformance = lookupConformance(
-        nominal->getDeclaredInterfaceType(), proto);
-    if (conformance) {
-      auto DC = conformance.getConcrete()->getDeclContext();
-      // Check whether this nominal type derives conformances to the protocol.
-      if (!DerivedConformance::derivesProtocolConformance(DC, nominal, proto))
-        return nullptr;
-    }
-
-    // Retrieve the requirement.
-    return proto->getSingleRequirement(name);
-  };
-
-  // Properties.
-  if (isa<VarDecl>(requirement)) {
-    // RawRepresentable.rawValue
-    if (name.isSimpleName(ctx.Id_rawValue))
-      return getRequirement(KnownProtocolKind::RawRepresentable);
-
-    // Hashable.hashValue
-    if (name.isSimpleName(ctx.Id_hashValue))
-      return getRequirement(KnownProtocolKind::Hashable);
-
-    // CaseIterable.allValues
-    if (name.isSimpleName(ctx.Id_allCases))
-      return getRequirement(KnownProtocolKind::CaseIterable);
-
-    // _BridgedNSError._nsErrorDomain
-    if (name.isSimpleName(ctx.Id_nsErrorDomain))
-      return getRequirement(KnownProtocolKind::BridgedNSError);
-
-    // CodingKey.stringValue
-    if (name.isSimpleName(ctx.Id_stringValue))
-      return getRequirement(KnownProtocolKind::CodingKey);
-
-    // CodingKey.intValue
-    if (name.isSimpleName(ctx.Id_intValue))
-      return getRequirement(KnownProtocolKind::CodingKey);
-
-    // AdditiveArithmetic.zero
-    if (name.isSimpleName(ctx.Id_zero))
-      return getRequirement(KnownProtocolKind::AdditiveArithmetic);
-
-    // Actor.unownedExecutor
-    if (name.isSimpleName(ctx.Id_unownedExecutor)) {
-      if (nominal->isDistributedActor()) {
-        return getRequirement(KnownProtocolKind::DistributedActor);
-      } else {
-        return getRequirement(KnownProtocolKind::Actor);
-      }
-    }
-
-    // DistributedActor.id
-    if (name.isSimpleName(ctx.Id_id))
-      return getRequirement(KnownProtocolKind::DistributedActor);
-
-    // DistributedActor.actorSystem
-    if (name.isSimpleName(ctx.Id_actorSystem))
-      return getRequirement(KnownProtocolKind::DistributedActor);
-
-    return nullptr;
-  }
-
-  // Functions.
-  if (auto func = dyn_cast<FuncDecl>(requirement)) {
-    if (func->isOperator() && name.getBaseName() == "<")
-      return getRequirement(KnownProtocolKind::Comparable);
-    
-    if (func->isOperator() && name.getBaseName() == "==")
-      return getRequirement(KnownProtocolKind::Equatable);
-
-    // AdditiveArithmetic.+
-    // AdditiveArithmetic.-
-    if (func->isOperator() && name.getArgumentNames().size() == 2 &&
-        (name.getBaseName() == "+" || name.getBaseName() == "-")) {
-      return getRequirement(KnownProtocolKind::AdditiveArithmetic);
-    }
-
-    // Differentiable.move(by:)
-    if (name.isCompoundName() && name.getBaseName() == ctx.Id_move) {
-      auto argumentNames = name.getArgumentNames();
-      if (argumentNames.size() == 1 && argumentNames[0] == ctx.Id_by)
-        return getRequirement(KnownProtocolKind::Differentiable);
-    }
-
-    // Encodable.encode(to: Encoder)
-    if (name.isCompoundName() && name.getBaseName() == ctx.Id_encode) {
-      auto argumentNames = name.getArgumentNames();
-      if (argumentNames.size() == 1 && argumentNames[0] == ctx.Id_to)
-        return getRequirement(KnownProtocolKind::Encodable);
-    }
-
-    // Hashable.hash(into: inout Hasher)
-    if (name.isCompoundName() && name.getBaseName() == ctx.Id_hash) {
-      auto argumentNames = name.getArgumentNames();
-      if (argumentNames.size() == 1 && argumentNames[0] == ctx.Id_into)
-        return getRequirement(KnownProtocolKind::Hashable);
-    }
-
-    // static DistributedActor.resolve(id:using:)
-    if (name.isCompoundName() && name.getBaseName() == ctx.Id_resolve &&
-        func->isStatic()) {
-      auto argumentNames = name.getArgumentNames();
-      if (argumentNames.size() == 2 &&
-          argumentNames[0] == ctx.Id_id &&
-          argumentNames[1] == ctx.Id_using) {
-        return getRequirement(KnownProtocolKind::DistributedActor);
-      }
-    }
-
-    // DistributedActor.actorSystem
-    if (name.isCompoundName() &&
-        name.getBaseName() == ctx.Id_invokeHandlerOnReturn)
-      return getRequirement(KnownProtocolKind::DistributedActorSystem);
-
-    return nullptr;
-  }
-
-  // Initializers.
-  if (auto ctor = dyn_cast<ConstructorDecl>(requirement)) {
-    auto argumentNames = name.getArgumentNames();
-    if (argumentNames.size() == 1) {
-      if (argumentNames[0] == ctx.Id_rawValue)
-        return getRequirement(KnownProtocolKind::RawRepresentable);
-
-      // CodingKey.init?(stringValue:), CodingKey.init?(intValue:)
-      if (ctor->isFailable() &&
-          !ctor->isImplicitlyUnwrappedOptional() &&
-          (argumentNames[0] == ctx.Id_stringValue ||
-           argumentNames[0] == ctx.Id_intValue))
-        return getRequirement(KnownProtocolKind::CodingKey);
-
-      // Decodable.init(from: Decoder)
-      if (argumentNames[0] == ctx.Id_from)
-        return getRequirement(KnownProtocolKind::Decodable);
-    }
-
-    return nullptr;
-  }
-
-  // Associated types.
-  if (isa<AssociatedTypeDecl>(requirement)) {
-    // RawRepresentable.RawValue
-    if (name.isSimpleName(ctx.Id_RawValue))
-      return getRequirement(KnownProtocolKind::RawRepresentable);
-
-    // CaseIterable.AllCases
-    if (name.isSimpleName(ctx.Id_AllCases))
-      return getRequirement(KnownProtocolKind::CaseIterable);
-
-    // Differentiable.TangentVector
-    if (name.isSimpleName(ctx.Id_TangentVector))
-      return getRequirement(KnownProtocolKind::Differentiable);
-
-    return nullptr;
-  }
-
-  return nullptr;
-}
-
-DeclRefExpr *
-DerivedConformance::createSelfDeclRef(AbstractFunctionDecl *fn) {
-  ASTContext &C = fn->getASTContext();
-
-  auto selfDecl = fn->getImplicitSelfDecl();
-  return new (C) DeclRefExpr(selfDecl, DeclNameLoc(), /*implicit*/true);
-}
-
-CallExpr *
-DerivedConformance::createBuiltinCall(ASTContext &ctx,
-                                      BuiltinValueKind builtin,
-                                      ArrayRef<Type> typeArgs,
-                                      ArrayRef<Expr *> args) {
-  auto name = ctx.getIdentifier(getBuiltinName(builtin));
-  auto decl = getBuiltinValueDecl(ctx, name);
-  assert(decl);
-
-  ConcreteDeclRef declRef = decl;
-  auto fnType = decl->getInterfaceType();
-  if (auto genericFnType = fnType->getAs<GenericFunctionType>()) {
-    auto generics = genericFnType->getGenericSignature();
-    auto subs = SubstitutionMap::get(generics, typeArgs,
-                                     LookUpConformanceInModule{});
-    declRef = ConcreteDeclRef(decl, subs);
-    fnType = genericFnType->substGenericArgs(subs);
-  } else {
-    assert(typeArgs.empty());
-  }
-
-  auto resultType = fnType->castTo<FunctionType>()->getResult();
-
-  Expr *ref = new (ctx) DeclRefExpr(declRef, DeclNameLoc(),
-                                    /*Implicit=*/true,
-                                    AccessSemantics::Ordinary, fnType);
-  auto *argList = ArgumentList::forImplicitUnlabeled(ctx, args);
-  auto *call = CallExpr::createImplicit(ctx, ref, argList);
-  call->setType(resultType);
-  call->setThrows(nullptr);
-
-  return call;
-}
-
-CallExpr *DerivedConformance::createDiagnoseUnavailableCodeReachedCallExpr(
-    ASTContext &ctx) {
-  FuncDecl *diagnoseDecl = ctx.getDiagnoseUnavailableCodeReached();
-  assert(diagnoseDecl);
-  auto diagnoseDeclRefExpr =
-      new (ctx) DeclRefExpr(diagnoseDecl, DeclNameLoc(), true);
-  diagnoseDeclRefExpr->setType(diagnoseDecl->getInterfaceType());
-  auto argList = ArgumentList::createImplicit(ctx, {});
-  auto callExpr = CallExpr::createImplicit(ctx, diagnoseDeclRefExpr, argList);
-  callExpr->setType(ctx.getNeverType());
-  callExpr->setThrows(nullptr);
-  return callExpr;
-}
-
-AccessorDecl *
-DerivedConformance::addGetterToReadOnlyDerivedProperty(VarDecl *property) {
-  auto getter = declareDerivedPropertyGetter(property);
-
-  property->setImplInfo(StorageImplInfo::getImmutableComputed());
-  property->setAccessors(SourceLoc(), {getter}, SourceLoc());
-
-  return getter;
-}
-
-AccessorDecl *
-DerivedConformance::declareDerivedPropertyGetter(VarDecl *property) {
-  auto &C = property->getASTContext();
-  auto parentDC = property->getDeclContext();
-  ParameterList *params = ParameterList::createEmpty(C);
-
-  auto getterDecl = AccessorDecl::create(
-      C,
-      /*FuncLoc=*/SourceLoc(), /*AccessorKeywordLoc=*/SourceLoc(),
-      AccessorKind::Get, property,
-      /*Async=*/false, /*AsyncLoc=*/SourceLoc(),
-      /*Throws=*/false, /*ThrowsLoc=*/SourceLoc(), /*ThrownType=*/TypeLoc(),
-      params, property->getInterfaceType(), parentDC);
-  getterDecl->setImplicit();
-  getterDecl->setIsTransparent(false);
-  getterDecl->copyFormalAccessFrom(property);
-
-  return getterDecl;
-}
-
-static VarDecl::Introducer
-mapIntroducer(DerivedConformance::SynthesizedIntroducer intro) {
-  switch (intro) {
-  case DerivedConformance::SynthesizedIntroducer::Let:
-    return VarDecl::Introducer::Let;
-  case DerivedConformance::SynthesizedIntroducer::Var:
-    return VarDecl::Introducer::Var;
-  }
-  llvm_unreachable("Invalid synthesized introducer!");
-}
-
-std::pair<VarDecl *, PatternBindingDecl *>
-DerivedConformance::declareDerivedProperty(SynthesizedIntroducer intro,
-                                           Identifier name,
-                                           Type propertyInterfaceType,
-                                           bool isStatic, bool isFinal) {
-  auto parentDC = getConformanceContext();
-
-  VarDecl *propDecl = new (Context) VarDecl(
-      /*IsStatic*/ isStatic, mapIntroducer(intro), SourceLoc(), name, parentDC);
-  propDecl->setImplicit();
-  propDecl->setSynthesized();
-  propDecl->copyFormalAccessFrom(Nominal, /*sourceIsParentContext*/ true);
-  propDecl->setInterfaceType(propertyInterfaceType);
-
-  auto propertyContextType =
-      getConformanceContext()->mapTypeIntoContext(propertyInterfaceType);
-
-  Pattern *propPat =
-      NamedPattern::createImplicit(Context, propDecl, propertyContextType);
-
-  propPat = TypedPattern::createImplicit(Context, propPat, propertyContextType);
-
-  auto *pbDecl = PatternBindingDecl::createImplicit(
-      Context, StaticSpellingKind::None, propPat, /*InitExpr*/ nullptr,
-      parentDC);
-  return {propDecl, pbDecl};
-}
-
-bool DerivedConformance::checkAndDiagnoseDisallowedContext(
-    ValueDecl *synthesizing) const {
-  // In general, conformances can't be synthesized in extensions across files;
-  // but we have to allow it as a special case for Equatable and Hashable on
-  // enums with no associated values to preserve source compatibility.
-  bool allowCrossfileExtensions = false;
-  if (Protocol->isSpecificProtocol(KnownProtocolKind::Equatable) ||
-      Protocol->isSpecificProtocol(KnownProtocolKind::Hashable)) {
-    auto ED = dyn_cast<EnumDecl>(Nominal);
-    allowCrossfileExtensions = ED && ED->hasOnlyCasesWithoutAssociatedValues();
-  }
-
-  if (!allowCrossfileExtensions &&
-      Nominal->getModuleScopeContext() !=
-          getConformanceContext()->getModuleScopeContext()) {
-    ConformanceDecl->diagnose(diag::cannot_synthesize_in_crossfile_extension,
-                              Nominal, synthesizing->getName(),
-                              getProtocolType());
-    Nominal->diagnose(diag::kind_declared_here, DescriptiveDeclKind::Type);
-
-    // Try to insert a stub.
-    auto Extension = cast<ExtensionDecl>(getConformanceContext());
-    auto FixitLocation = Extension->getBraces().Start;
-    llvm::SmallString<128> Text;
-    {
-      llvm::raw_svector_ostream SS(Text);
-      swift::printRequirementStub(synthesizing, Nominal,
-                                  Nominal->getDeclaredType(),
-                                  Extension->getStartLoc(), SS);
-      if (!Text.empty()) {
-        ConformanceDecl->diagnose(diag::missing_witnesses_general)
-          .fixItInsertAfter(FixitLocation, Text.str());
-      }
-    }
-    return true;
-  }
-
-  // A non-final class can't have a protocol-witnesses initializer in an
-  // extension.
-  if (auto CD = dyn_cast<ClassDecl>(Nominal)) {
-    if (!CD->isSemanticallyFinal() && isa<ConstructorDecl>(synthesizing) &&
-        isa<ExtensionDecl>(ConformanceDecl)) {
-      ConformanceDecl->diagnose(
-          diag::cannot_synthesize_init_in_extension_of_nonfinal,
-          getProtocolType(), synthesizing->getName());
-      return true;
-    }
-  }
-
-  if (auto ED = dyn_cast<EnumDecl>(Nominal)) {
-    if (ED->getAllCases().empty() &&
-        (Protocol->isSpecificProtocol(KnownProtocolKind::Encodable) ||
-         Protocol->isSpecificProtocol(KnownProtocolKind::Decodable))) {
-      ED->diagnose(diag::codable_synthesis_empty_enum_not_supported,
-                   getProtocolType(), Nominal->getBaseIdentifier());
-      return false;
-    }
-  }
-
-  return false;
-}
-
-/// Returns a generated guard statement that checks whether the given lhs and
-/// rhs expressions are equal. If not equal, the else block for the guard
-/// returns `guardReturnValue`.
-/// \p C The AST context.
-/// \p lhsExpr The first expression to compare for equality.
-/// \p rhsExpr The second expression to compare for equality.
-/// \p guardReturnValue The expression to return if the two sides are not equal 
-GuardStmt *DerivedConformance::returnIfNotEqualGuard(ASTContext &C,
-                                        Expr *lhsExpr,
-                                        Expr *rhsExpr, 
-                                        Expr *guardReturnValue) {
-  SmallVector<StmtConditionElement, 1> conditions;
-  SmallVector<ASTNode, 1> statements;
-
-  auto *returnStmt = ReturnStmt::createImplicit(C, guardReturnValue);
-  statements.push_back(returnStmt);
-
-  // Next, generate the condition being checked.
-  // lhs == rhs
-  auto cmpFuncExpr = new (C) UnresolvedDeclRefExpr(
-    DeclNameRef(C.Id_EqualsOperator), DeclRefKind::BinaryOperator,
-    DeclNameLoc());
-  auto *cmpExpr = BinaryExpr::create(C, lhsExpr, cmpFuncExpr, rhsExpr,
-                                     /*implicit*/ true);
-  conditions.emplace_back(cmpExpr);
-
-  // Build and return the complete guard statement.
-  // guard lhs == rhs else { return lhs < rhs }
-  auto body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc());
-  return new (C) GuardStmt(SourceLoc(), C.AllocateCopy(conditions), body);
-}
-/// Returns a generated guard statement that checks whether the given lhs and
-/// rhs expressions are equal. If not equal, the else block for the guard
-/// returns `false`.
-/// \p C The AST context.
-/// \p lhsExpr The first expression to compare for equality.
-/// \p rhsExpr The second expression to compare for equality. 
-GuardStmt *DerivedConformance::returnFalseIfNotEqualGuard(ASTContext &C,
-                                        Expr *lhsExpr,
-                                        Expr *rhsExpr) {
-  // return false
-  auto falseExpr = new (C) BooleanLiteralExpr(false, SourceLoc(), true);
-  return returnIfNotEqualGuard(C, lhsExpr, rhsExpr, falseExpr);
-}
-/// Returns a generated guard statement that checks whether the given expr is true.
-/// If it is false, the else block for the guard returns `nil`.
-/// \p C The AST context.
-/// \p testExpr The expression that should be tested.
-/// \p baseType The wrapped type of the to-be-returned Optional<Wrapped>.
-GuardStmt *DerivedConformance::returnNilIfFalseGuardTypeChecked(ASTContext &C,
-                                        Expr *testExpr,
-                                        Type optionalWrappedType) {
-  auto nilExpr = new (C) NilLiteralExpr(SourceLoc(), /*implicit=*/true);
-  nilExpr->setType(optionalWrappedType->wrapInOptionalType());
-
-  SmallVector<StmtConditionElement, 1> conditions;
-  SmallVector<ASTNode, 1> statements;
-
-  auto *returnStmt = ReturnStmt::createImplicit(C, nilExpr);
-  statements.push_back(returnStmt);
-
-  // Next, generate the condition being checked.
-  conditions.emplace_back(testExpr);
-
-  // Build and return the complete guard statement.
-  // guard lhs == rhs else { return lhs < rhs }
-  auto body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc());
-  return new (C) GuardStmt(SourceLoc(), C.AllocateCopy(conditions), body);
-}
-/// Returns a generated guard statement that checks whether the given lhs and
-/// rhs expressions are equal. If not equal, the else block for the guard
-/// returns lhs < rhs.
-/// \p C The AST context.
-/// \p lhsExpr The first expression to compare for equality.
-/// \p rhsExpr The second expression to compare for equality. 
-GuardStmt *DerivedConformance::returnComparisonIfNotEqualGuard(ASTContext &C,
-                                        Expr *lhsExpr,
-                                        Expr *rhsExpr) {
-  // return lhs < rhs
-  auto ltFuncExpr = new (C) UnresolvedDeclRefExpr(
-    DeclNameRef(C.Id_LessThanOperator), DeclRefKind::BinaryOperator,
-    DeclNameLoc());
-  auto *ltExpr = BinaryExpr::create(C, lhsExpr, ltFuncExpr, rhsExpr,
-                                    /*implicit*/ true);
-  return returnIfNotEqualGuard(C, lhsExpr, rhsExpr, ltExpr);
-}
-
-/// Build a type-checked integer literal.
-static IntegerLiteralExpr *buildIntegerLiteral(ASTContext &C, unsigned index) {
-  Type intType = C.getIntType();
-
-  auto literal = IntegerLiteralExpr::createFromUnsigned(C, index, SourceLoc());
-  literal->setType(intType);
-  literal->setBuiltinInitializer(C.getIntBuiltinInitDecl(C.getIntDecl()));
-
-  return literal;
-}
-
-/// Create AST statements which convert from an enum to an Int with a switch.
-/// \p stmts The generated statements are appended to this vector.
-/// \p parentDC Either an extension or the enum itself.
-/// \p enumDecl The enum declaration.
-/// \p enumVarDecl The enum input variable.
-/// \p funcDecl The parent function.
-/// \p indexName The name of the output variable.
-/// \return A DeclRefExpr of the output variable (of type Int).
-DeclRefExpr *DerivedConformance::convertEnumToIndex(SmallVectorImpl<ASTNode> &stmts,
-                                       DeclContext *parentDC,
-                                       EnumDecl *enumDecl,
-                                       VarDecl *enumVarDecl,
-                                       AbstractFunctionDecl *funcDecl,
-                                       const char *indexName) {
-  ASTContext &C = enumDecl->getASTContext();
-  Type enumType = enumVarDecl->getTypeInContext();
-  Type intType = C.getIntType();
-
-  auto indexVar = new (C) VarDecl(/*IsStatic*/false, VarDecl::Introducer::Var,
-                                  SourceLoc(), C.getIdentifier(indexName),
-                                  funcDecl);
-  indexVar->setInterfaceType(intType);
-  indexVar->setImplicit();
-
-  // generate: var indexVar
-  Pattern *indexPat = NamedPattern::createImplicit(C, indexVar, intType);
-  indexPat = TypedPattern::createImplicit(C, indexPat, intType);
-
-  auto *indexBind = PatternBindingDecl::createImplicit(
-      C, StaticSpellingKind::None, indexPat, /*InitExpr*/ nullptr, funcDecl);
-
-  unsigned index = 0;
-  SmallVector<CaseStmt *, 4> cases;
-  for (auto elt : enumDecl->getAllElements()) {
-    if (auto *unavailableElementCase =
-            DerivedConformance::unavailableEnumElementCaseStmt(enumType, elt,
-                                                               funcDecl)) {
-      cases.push_back(unavailableElementCase);
-      continue;
-    }
-
-    // generate: case .<Case>:
-    auto *pat = EnumElementPattern::createImplicit(
-        enumType, elt, /*subPattern*/ nullptr, /*DC*/ funcDecl);
-
-    auto labelItem = CaseLabelItem(pat);
-
-    // generate: indexVar = <index>
-    auto indexExpr = buildIntegerLiteral(C, index++);
-
-    auto indexRef = new (C) DeclRefExpr(indexVar, DeclNameLoc(),
-                                        /*implicit*/true,
-                                        AccessSemantics::Ordinary,
-                                        LValueType::get(intType));
-    auto assignExpr = new (C) AssignExpr(indexRef, SourceLoc(),
-                                         indexExpr, /*implicit*/ true);
-    assignExpr->setType(TupleType::getEmpty(C));
-    auto body = BraceStmt::create(C, SourceLoc(), ASTNode(assignExpr),
-                                  SourceLoc());
-    cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
-                                     labelItem, SourceLoc(), SourceLoc(), body,
-                                     /*case body vardecls*/ std::nullopt));
-  }
-
-  // generate: switch enumVar { }
-  auto enumRef = new (C) DeclRefExpr(enumVarDecl, DeclNameLoc(),
-                                     /*implicit*/true,
-                                     AccessSemantics::Ordinary,
-                                     enumVarDecl->getTypeInContext());
-  auto switchStmt =
-      SwitchStmt::createImplicit(LabeledStmtInfo(), enumRef, cases, C);
-
-  stmts.push_back(indexBind);
-  stmts.push_back(switchStmt);
-
-  return new (C) DeclRefExpr(indexVar, DeclNameLoc(), /*implicit*/ true,
-                             AccessSemantics::Ordinary, intType);
-}
-
-/// Returns the ParamDecl for each associated value of the given enum whose type
-/// does not conform to a protocol
-/// \p theEnum The enum whose elements and associated values should be checked.
-/// \p protocol The protocol being requested.
-/// \return The ParamDecl of each associated value whose type does not conform.
-SmallVector<ParamDecl *, 4>
-DerivedConformance::associatedValuesNotConformingToProtocol(
-    DeclContext *DC, EnumDecl *theEnum, ProtocolDecl *protocol) {
-  SmallVector<ParamDecl *, 4> nonconformingAssociatedValues;
-  for (auto elt : theEnum->getAllElements()) {
-    auto PL = elt->getParameterList();
-    if (!PL)
-      continue;
-
-    for (auto param : *PL) {
-      auto type = param->getInterfaceType();
-      if (checkConformance(DC->mapTypeIntoContext(type), protocol).isInvalid()) {
-        nonconformingAssociatedValues.push_back(param);
-      }
-    }
-  }
-  return nonconformingAssociatedValues;
-}
-
-/// Returns true if, for every element of the given enum, it either has no
-/// associated values or all of them conform to a protocol.
-/// \p theEnum The enum whose elements and associated values should be checked.
-/// \p protocol The protocol being requested.
-/// \return True if all associated values of all elements of the enum conform.
-bool DerivedConformance::allAssociatedValuesConformToProtocol(DeclContext *DC,
-                                                 EnumDecl *theEnum,
-                                                 ProtocolDecl *protocol) {
-  return associatedValuesNotConformingToProtocol(DC, theEnum, protocol).empty();
-}
-
-/// Returns the pattern used to match and bind the associated values (if any) of
-/// an enum case.
-/// \p enumElementDecl The enum element to match.
-/// \p varPrefix The prefix character for variable names (e.g., a0, a1, ...).
-/// \p varContext The context into which payload variables should be declared.
-/// \p boundVars The array to which the pattern's variables will be appended.
-/// \p useLabels If the argument has a label, use it instead of the generated
-/// name.
-Pattern *DerivedConformance::enumElementPayloadSubpattern(
-    EnumElementDecl *enumElementDecl, char varPrefix, DeclContext *varContext,
-    SmallVectorImpl<VarDecl *> &boundVars, bool useLabels) {
-  auto parentDC = enumElementDecl->getDeclContext();
-  ASTContext &C = parentDC->getASTContext();
-
-  // No arguments, so no subpattern to match.
-  if (!enumElementDecl->hasAssociatedValues())
-    return nullptr;
-
-  auto payloadType = enumElementDecl->getPayloadInterfaceType();
-  if (auto tupleType = payloadType->getAs<TupleType>()) {
-    // Either multiple (labeled or unlabeled) arguments, or one labeled
-    // argument. Return a tuple pattern that matches the enum element in arity,
-    // types, and labels. For example:
-    // case a(x: Int) => (x: let a0)
-    // case b(Int, String) => (let a0, let a1)
-    SmallVector<TuplePatternElt, 4> elementPatterns;
-    int index = 0;
-    for (auto tupleElement : tupleType->getElements()) {
-      VarDecl *payloadVar;
-      if (useLabels && tupleElement.hasName()) {
-        payloadVar =
-            new (C) VarDecl(/*IsStatic*/ false, VarDecl::Introducer::Let,
-                            SourceLoc(), tupleElement.getName(), varContext);
-        payloadVar->setInterfaceType(tupleElement.getType());
-      } else {
-        payloadVar = indexedVarDecl(varPrefix, index++, tupleElement.getType(),
-                                    varContext);
-      }
-      boundVars.push_back(payloadVar);
-
-      auto namedPattern = new (C) NamedPattern(payloadVar);
-      namedPattern->setImplicit();
-      auto letPattern = BindingPattern::createImplicit(
-          C, VarDecl::Introducer::Let, namedPattern);
-      elementPatterns.push_back(TuplePatternElt(tupleElement.getName(),
-                                                SourceLoc(), letPattern));
-    }
-
-    auto pat = TuplePattern::createImplicit(C, elementPatterns);
-    pat->setImplicit();
-    return pat;
-  }
-
-  // Otherwise, a one-argument unlabeled payload. Return a paren pattern whose
-  // underlying type is the same as the payload. For example:
-  // case a(Int) => (let a0)
-  auto payloadVar = indexedVarDecl(varPrefix, 0, payloadType, varContext);
-  boundVars.push_back(payloadVar);
-
-  auto namedPattern = new (C) NamedPattern(payloadVar);
-  namedPattern->setImplicit();
-  auto letPattern = new (C)
-      BindingPattern(SourceLoc(), VarDecl::Introducer::Let, namedPattern);
-  return ParenPattern::createImplicit(C, letPattern);
-}
-
-CaseStmt *DerivedConformance::unavailableEnumElementCaseStmt(
-    Type enumType, EnumElementDecl *elt, DeclContext *parentDC,
-    unsigned subPatternCount) {
-  assert(subPatternCount > 0);
-
-  ASTContext &C = parentDC->getASTContext();
-  if (!elt->isUnreachableAtRuntime() ||
-      elt->getParentEnum()->isUnreachableAtRuntime())
-    return nullptr;
-
-  // If the stdlib isn't new enough to contain the helper function for
-  // diagnosing execution of unavailable code then just synthesize this case
-  // normally.
-  if (!C.getDiagnoseUnavailableCodeReached())
-    return nullptr;
-
-  auto createElementPattern = [&]() -> EnumElementPattern * {
-    // .<elt>
-    return EnumElementPattern::createImplicit(
-        enumType, elt, /*subPattern*/ nullptr, /*DC*/ parentDC);
-  };
-
-  Pattern *labelItemPattern;
-  if (subPatternCount > 1) {
-    SmallVector<TuplePatternElt, 2> tuplePatternElts;
-    for (unsigned i = 0; i < subPatternCount; i++) {
-      tuplePatternElts.push_back(TuplePatternElt(createElementPattern()));
-    }
-
-    // (.<elt>, ..., .<elt>)
-    auto caseTuplePattern = TuplePattern::createImplicit(C, tuplePatternElts);
-    caseTuplePattern->setImplicit();
-    labelItemPattern = caseTuplePattern;
-  } else {
-    labelItemPattern = createElementPattern();
-  }
-
-  auto labelItem = CaseLabelItem(labelItemPattern);
-  auto *callExpr =
-      DerivedConformance::createDiagnoseUnavailableCodeReachedCallExpr(C);
-  auto body = BraceStmt::create(C, SourceLoc(), {callExpr}, SourceLoc());
-  return CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(), labelItem,
-                          SourceLoc(), SourceLoc(), body, {},
-                          /*implicit*/ true);
-}
-
-/// Creates a named variable based on a prefix character and a numeric index.
-/// \p prefixChar The prefix character for the variable's name.
-/// \p index The numeric index to append to the variable's name.
-/// \p type The type of the variable.
-/// \p varContext The context of the variable.
-/// \return A VarDecl named with the prefix and number.
-VarDecl *DerivedConformance::indexedVarDecl(char prefixChar, int index, Type type,
-                               DeclContext *varContext) {
-  ASTContext &C = varContext->getASTContext();
-
-  llvm::SmallString<8> indexVal;
-  indexVal.append(1, prefixChar);
-  APInt(32, index).toString(indexVal, 10, /*signed*/ false);
-  auto indexStr = C.AllocateCopy(indexVal);
-  auto indexStrRef = StringRef(indexStr.data(), indexStr.size());
-
-  auto varDecl = new (C) VarDecl(/*IsStatic*/false, VarDecl::Introducer::Let,
-                                 SourceLoc(), C.getIdentifier(indexStrRef),
-                                 varContext);
-  varDecl->setInterfaceType(type);
-  return varDecl;
-}
-
-bool swift::memberwiseAccessorsRequireActorIsolation(NominalTypeDecl *nominal) {
-  if (!getActorIsolation(nominal).isActorIsolated())
-    return false;
-
-  for (auto property : nominal->getStoredProperties()) {
-    if (!property->isUserAccessible())
-      continue;
-
-    if (!property->isLet())
-      return true;
-  }
-
-  return false;
-}
diff --git a/lib/Sema/DerivedConformances.h b/lib/Sema/DerivedConformances.h
deleted file mode 100644
index ba145adbfce64..0000000000000
--- a/lib/Sema/DerivedConformances.h
+++ /dev/null
@@ -1,479 +0,0 @@
-//===--- DerivedConformances.h - Derived protocol conformance ---*- C++ -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-//
-//  This file defines entry points to synthesize compiler-derived conformances
-//  to certain known protocols.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef SWIFT_SEMA_DERIVEDCONFORMANCES_H
-#define SWIFT_SEMA_DERIVEDCONFORMANCES_H
-
-#include "swift/Basic/LLVM.h"
-#include "swift/AST/Builtins.h"
-#include <utility>
-
-namespace swift {
-class AbstractFunctionDecl;
-class AccessorDecl;
-class AssociatedTypeDecl;
-class ASTContext;
-struct ASTNode;
-class CallExpr;
-class CaseStmt;
-class Decl;
-class DeclContext;
-class DeclRefExpr;
-class EnumDecl;
-class EnumElementDecl;
-class Expr;
-class GuardStmt;
-class Identifier;
-class NominalTypeDecl;
-class ParamDecl;
-class Pattern;
-class PatternBindingDecl;
-class ProtocolDecl;
-class StructDecl;
-class Type;
-class TypeDecl;
-class ValueDecl;
-class VarDecl;
-
-class DerivedConformance {
-public:
-  enum class SynthesizedIntroducer : bool { Let, Var };
-
-public:
-  ASTContext &Context;
-  const NormalProtocolConformance *Conformance;
-  Decl *ConformanceDecl;
-  NominalTypeDecl *Nominal;
-  ProtocolDecl *Protocol;
-
-  DerivedConformance(const NormalProtocolConformance *conformance,
-                     NominalTypeDecl *nominal, ProtocolDecl *protocol);
-
-  /// Retrieve the context in which the conformance is declared (either the
-  /// nominal type, or an extension of it) as a \c DeclContext.
-  DeclContext *getConformanceContext() const;
-
-  /// Retrieve the module in which the conformance is declared.
-  ModuleDecl *getParentModule() const;
-
-  /// Add \c children as members of the context that declares the conformance.
-  void addMembersToConformanceContext(ArrayRef<Decl *> children);
-  /// Add \c member right after the \c hint member which may be the tail
-  void addMemberToConformanceContext(Decl *member, Decl* hint);
-  /// Add \c member in front of any other existing members
-  void addMemberToConformanceContext(Decl *member, bool insertAtHead);
-
-  /// Get the declared type of the protocol that this is conformance is for.
-  Type getProtocolType() const;
-
-  /// Returns the VarDecl of each stored property in the given struct whose type
-  /// does not conform to a protocol.
-  /// \p theStruct The struct whose stored properties should be checked.
-  /// \p protocol The protocol being requested.
-  /// \return The VarDecl of each stored property whose type does not conform.
-  static SmallVector<VarDecl *, 3> storedPropertiesNotConformingToProtocol(
-      DeclContext *DC, StructDecl *theStruct, ProtocolDecl *protocol);
-
-  /// True if the type can implicitly derive a conformance for the given
-  /// protocol.
-  ///
-  /// If true, explicit conformance checking will synthesize implicit
-  /// declarations for requirements of the protocol that are not satisfied by
-  /// the type's explicit members.
-  ///
-  /// \param nominal The nominal type for which we are determining whether to
-  /// derive a witness.
-  ///
-  /// \param protocol The protocol whose requirements are being derived.
-  ///
-  /// \return True if the type can implicitly derive a conformance for the
-  /// given protocol.
-  static bool derivesProtocolConformance(DeclContext *DC,
-                                         NominalTypeDecl *nominal,
-                                         ProtocolDecl *protocol);
-
-  /// Diagnose problems, if any, preventing automatic derivation of protocol
-  /// requirements
-  ///
-  /// \param nominal The nominal type for which we would like to diagnose
-  /// derivation failures
-  ///
-  /// \param protocol The protocol with requirements we would like to diagnose
-  /// derivation failures for
-  static void tryDiagnoseFailedDerivation(DeclContext *DC,
-                                          NominalTypeDecl *nominal,
-                                          ProtocolDecl *protocol);
-
-  /// Diagnose any members which do not conform to the protocol for which
-  /// we were trying to synthesize the conformance to.
-  ///
-  /// \param nominal The nominal type for which we would like to diagnose
-  /// derivation failures
-  ///
-  /// \param protocol The protocol with requirements we would like to diagnose
-  /// derivation failures for
-  static void diagnoseAnyNonConformingMemberTypes(DeclContext *DC,
-                                                  NominalTypeDecl *nominal,
-                                                  ProtocolDecl *protocol);
-
-  /// Diagnose the declaration for which we were trying to synthesize
-  /// the conformance for, if the synthesis is not supported for that
-  /// declaration.
-  ///
-  /// \param nominal The nominal type for which we would like to diagnose
-  /// derivation failures
-  ///
-  /// \param protocol The protocol with requirements we would like to diagnose
-  /// derivation failures for
-  static void diagnoseIfSynthesisUnsupportedForDecl(NominalTypeDecl *nominal,
-                                                    ProtocolDecl *protocol);
-
-  /// Determine the derivable requirement that would satisfy the given
-  /// requirement, if there is one.
-  ///
-  /// \param nominal The nominal type for which we are determining whether to
-  /// derive a witness.
-  ///
-  /// \param requirement The requirement for which we are checking for a
-  /// derivation. This requirement need not be within a derivable protocol,
-  /// because derivable requirements can get restated in inherited unrelated
-  /// or unrelated protocols.
-  ///
-  /// \returns The requirement whose witness could be derived to potentially
-  /// satisfy this given requirement, or NULL if there is no such requirement.
-  static ValueDecl *getDerivableRequirement(NominalTypeDecl *nominal,
-                                            ValueDecl *requirement);
-
-  /// Determine if an AdditiveArithmetic requirement can be derived for a type.
-  ///
-  /// \returns True if the requirement can be derived.
-  static bool canDeriveAdditiveArithmetic(NominalTypeDecl *type,
-                                          DeclContext *DC);
-
-  /// Derive an AdditiveArithmetic requirement for a nominal type.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveAdditiveArithmetic(ValueDecl *requirement);
-
-  /// Determine if a Differentiable requirement can be derived for a nominal
-  /// type.
-  ///
-  /// \returns True if the requirement can be derived.
-  static bool canDeriveDifferentiable(NominalTypeDecl *type, DeclContext *DC,
-                                      ValueDecl *requirement);
-
-  /// Derive a Differentiable requirement for a nominal type.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveDifferentiable(ValueDecl *requirement);
-
-  /// Derive a Differentiable type witness for a nominal type.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  std::pair<Type, TypeDecl *>
-  deriveDifferentiable(AssociatedTypeDecl *assocType);
-
-  /// Derive a CaseIterable requirement for an enum if it has no associated
-  /// values for any of its cases.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveCaseIterable(ValueDecl *requirement);
-
-  /// Derive a CaseIterable type witness for an enum if it has no associated
-  /// values for any of its cases.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  Type deriveCaseIterable(AssociatedTypeDecl *assocType);
-
-  /// Determine if a RawRepresentable requirement can be derived for a type.
-  ///
-  /// This is implemented for non-empty enums without associated values,
-  /// that declare a raw type in the inheritance clause.
-  static bool canDeriveRawRepresentable(DeclContext *DC, NominalTypeDecl *type);
-
-  /// Derive a RawRepresentable requirement for an enum, if it has a valid
-  /// raw type and raw values for all of its cases.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveRawRepresentable(ValueDecl *requirement);
-
-  /// Derive a RawRepresentable type witness for an enum, if it has a valid
-  /// raw type and raw values for all of its cases.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  Type deriveRawRepresentable(AssociatedTypeDecl *assocType);
-
-  /// Determine if a Comparable requirement can be derived for a type.
-  ///
-  /// This is implemented for enums without associated or raw values.
-  ///
-  /// \returns True if the requirement can be derived.
-  static bool canDeriveComparable(DeclContext *DC, EnumDecl *enumeration);
-
-  /// Derive an Equatable requirement for a type.
-  ///
-  /// This is implemented for enums without associated or raw values.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveComparable(ValueDecl *requirement);
-
-  /// Diagnose problems, if any, preventing automatic derivation of Comparable
-  /// requirements
-  ///
-  /// \param nominal The nominal type for which we would like to diagnose
-  /// derivation failures
-  static void tryDiagnoseFailedComparableDerivation(DeclContext *DC,
-                                                    NominalTypeDecl *nominal);
-
-  /// Diagnose problems, if any, preventing automatic derivation of
-  /// DistributedActor requirements
-  ///
-  /// \param nominal The nominal type for which we would like to diagnose
-  /// derivation failures
-  static void tryDiagnoseFailedDistributedActorDerivation(DeclContext *DC,
-                                                    NominalTypeDecl *nominal);
-
-  /// Diagnose problems, if any, preventing automatic derivation of
-  /// DistributedActor requirements
-  ///
-  /// \param nominal The nominal type for which we would like to diagnose
-  /// derivation failures
-  static void
-  tryDiagnoseFailedDistributedActorSystemDerivation(DeclContext *DC,
-                                                    NominalTypeDecl *nominal);
-
-  /// Determine if an Equatable requirement can be derived for a type.
-  ///
-  /// This is implemented for enums without associated values or all-Equatable
-  /// associated values, and for structs with all-Equatable stored properties.
-  ///
-  /// \returns True if the requirement can be derived.
-  static bool canDeriveEquatable(DeclContext *DC, NominalTypeDecl *type);
-
-  /// Derive an Equatable requirement for a type.
-  ///
-  /// This is implemented for enums without associated values or all-Equatable
-  /// associated values, and for structs with all-Equatable stored properties.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveEquatable(ValueDecl *requirement);
-
-  /// Diagnose problems, if any, preventing automatic derivation of Equatable
-  /// requirements
-  ///
-  /// \param nominal The nominal type for which we would like to diagnose
-  /// derivation failures
-  static void tryDiagnoseFailedEquatableDerivation(DeclContext *DC,
-                                                   NominalTypeDecl *nominal);
-
-  /// Determine if a Hashable requirement can be derived for a type.
-  ///
-  /// This is implemented for enums without associated values or all-Hashable
-  /// associated values, and for structs with all-Hashable stored properties.
-  ///
-  /// \returns True if the requirement can be derived.
-  static bool canDeriveHashable(NominalTypeDecl *type);
-
-  /// Derive a Hashable requirement for a type.
-  ///
-  /// This is implemented for enums without associated values or all-Hashable
-  /// associated values, and for structs with all-Hashable stored properties.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveHashable(ValueDecl *requirement);
-
-  /// Diagnose problems, if any, preventing automatic derivation of Hashable
-  /// requirements
-  ///
-  /// \param nominal The nominal type for which we would like to diagnose
-  /// derivation failures
-  static void tryDiagnoseFailedHashableDerivation(DeclContext *DC,
-                                                  NominalTypeDecl *nominal);
-
-  /// Derive a _BridgedNSError requirement for an @objc enum type.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveBridgedNSError(ValueDecl *requirement);
-
-  /// Determine if \c Encodable can be derived for the given type.
-  static bool canDeriveEncodable(NominalTypeDecl *NTD);
-  /// Determine if \c Decodable can be derived for the given type.
-  static bool canDeriveDecodable(NominalTypeDecl *NTD);
-
-  /// Derive a CodingKey requirement for an enum type.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveCodingKey(ValueDecl *requirement);
-
-  /// Derive an Encodable requirement for a struct type.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveEncodable(ValueDecl *requirement);
-
-  /// Derive a Decodable requirement for a struct type.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveDecodable(ValueDecl *requirement);  
-
-  /// Identifiable may need to have the `ID` type witness synthesized explicitly
-  static bool canDeriveIdentifiable(NominalTypeDecl *nominal,
-                                    DeclContext *dc);
-
-  /// Whether we can derive the given DistributedActor requirement in the given context.
-  static bool canDeriveDistributedActor(NominalTypeDecl *nominal,
-                                        DeclContext *dc);
-
-  /// Whether we can derive the given DistributedActorSystem requirements.
-  static bool canDeriveDistributedActorSystem(NominalTypeDecl *nominal,
-                                              DeclContext *dc);
-
-  /// Derive a 'DistributedActor' requirement for an distributed actor.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveDistributedActor(ValueDecl *requirement);
-
-  /// Derive a 'DistributedActorSystem' requirement..
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveDistributedActorSystem(ValueDecl *requirement);
-
-  /// Derive a DistributedActor associated type for a distributed actor.
-  ///
-  /// \returns the derived type member, which will also be added to the type.
-  std::pair<Type, TypeDecl *> deriveDistributedActor(
-      AssociatedTypeDecl *assocType);
-
-  /// Determine if \c Actor can be derived for the given type.
-  static bool canDeriveActor(DeclContext *DC, NominalTypeDecl *NTD);
-
-  /// Derive an Actor witness for an actor type.
-  ///
-  /// \returns the derived member, which will also be added to the type.
-  ValueDecl *deriveActor(ValueDecl *requirement);
-
-  /// Declare a read-only property.
-  std::pair<VarDecl *, PatternBindingDecl *>
-  declareDerivedProperty(SynthesizedIntroducer intro, Identifier name,
-                         Type propertyContextType, bool isStatic, bool isFinal);
-
-  /// Add a getter to a derived property.  The property becomes read-only.
-  static AccessorDecl *addGetterToReadOnlyDerivedProperty(VarDecl *property);
-
-  /// Declare a getter for a derived property.
-  /// The getter will not be added to the property yet.
-  static AccessorDecl *declareDerivedPropertyGetter(VarDecl *property);
-
-  /// Build a reference to the 'self' decl of a derived function.
-  static DeclRefExpr *createSelfDeclRef(AbstractFunctionDecl *fn);
-
-  /// Build a builtin call.  By default, the call is assumed not to throw.
-  static CallExpr *createBuiltinCall(ASTContext &ctx,
-                                     BuiltinValueKind builtin,
-                                     ArrayRef<Type> typeArgs,
-                                     ArrayRef<Expr *> args);
-
-  /// Build a call to the stdlib function that should be called when unavailable
-  /// code is reached unexpectedly.
-  static CallExpr *
-  createDiagnoseUnavailableCodeReachedCallExpr(ASTContext &ctx);
-
-  /// Returns true if this derivation is trying to use a context that isn't
-  /// appropriate for deriving.
-  ///
-  /// \param synthesizing The decl that is being synthesized.
-  bool checkAndDiagnoseDisallowedContext(ValueDecl *synthesizing) const;
-
-  /// Returns a generated guard statement that checks whether the given lhs and
-  /// rhs expressions are equal. If not equal, the else block for the guard
-  /// returns `guardReturnValue`.
-  /// \p C The AST context.
-  /// \p lhsExpr The first expression to compare for equality.
-  /// \p rhsExpr The second expression to compare for equality.
-  /// \p guardReturnValue The expression to return if the two sides are not
-  /// equal
-  static GuardStmt *returnIfNotEqualGuard(ASTContext &C, Expr *lhsExpr,
-                                          Expr *rhsExpr,
-                                          Expr *guardReturnValue);
-  // return false
-  static GuardStmt *returnFalseIfNotEqualGuard(ASTContext &C, Expr *lhsExpr,
-                                               Expr *rhsExpr);
-
-  // Return `nil` is the `testExp` is `false`.
-  static GuardStmt *returnNilIfFalseGuardTypeChecked(ASTContext &C,
-                                                     Expr *testExpr,
-                                                     Type optionalWrappedType);
-
-  // return lhs < rhs
-  static GuardStmt *
-  returnComparisonIfNotEqualGuard(ASTContext &C, Expr *lhsExpr, Expr *rhsExpr);
-
-  /// Returns the ParamDecl for each associated value of the given enum whose
-  /// type does not conform to a protocol \p theEnum The enum whose elements and
-  /// associated values should be checked. \p protocol The protocol being
-  /// requested. \return The ParamDecl of each associated value whose type does
-  /// not conform.
-  static SmallVector<ParamDecl *, 4>
-  associatedValuesNotConformingToProtocol(DeclContext *DC, EnumDecl *theEnum,
-                                          ProtocolDecl *protocol);
-
-  /// Returns true if, for every element of the given enum, it either has no
-  /// associated values or all of them conform to a protocol.
-  /// \p theEnum The enum whose elements and associated values should be
-  /// checked. \p protocol The protocol being requested. \return True if all
-  /// associated values of all elements of the enum conform.
-  static bool allAssociatedValuesConformToProtocol(DeclContext *DC,
-                                                   EnumDecl *theEnum,
-                                                   ProtocolDecl *protocol);
-  /// Create AST statements which convert from an enum to an Int with a switch.
-  /// \p stmts The generated statements are appended to this vector.
-  /// \p parentDC Either an extension or the enum itself.
-  /// \p enumDecl The enum declaration.
-  /// \p enumVarDecl The enum input variable.
-  /// \p funcDecl The parent function.
-  /// \p indexName The name of the output variable.
-  /// \return A DeclRefExpr of the output variable (of type Int).
-  static DeclRefExpr *
-  convertEnumToIndex(SmallVectorImpl<ASTNode> &stmts, DeclContext *parentDC,
-                     EnumDecl *enumDecl, VarDecl *enumVarDecl,
-                     AbstractFunctionDecl *funcDecl, const char *indexName);
-
-  static Pattern *enumElementPayloadSubpattern(
-      EnumElementDecl *enumElementDecl, char varPrefix, DeclContext *varContext,
-      SmallVectorImpl<VarDecl *> &boundVars, bool useLabels = false);
-
-  /// Creates a synthesized case statement that has the following structure:
-  ///
-  ///     case .<elt>, ..., .<elt>:
-  ///       _diagnoseUnavailableCodeReached()
-  ///
-  /// The number of \c .<elt> matches is equal to \p subPatternCount.
-  static CaseStmt *unavailableEnumElementCaseStmt(
-      Type enumType, EnumElementDecl *enumElementDecl, DeclContext *parentDC,
-      unsigned subPatternCount = 1);
-
-  static VarDecl *indexedVarDecl(char prefixChar, int index, Type type,
-                                 DeclContext *varContext);
-};
-
-/// Determine whether any "memberwise" accessors, which walk through the
-/// stored properties of the given nominal type, require actor isolation
-/// because they involve mutable state.
-bool memberwiseAccessorsRequireActorIsolation(NominalTypeDecl *nominal);
-
-} // namespace swift
-
-#endif
diff --git a/lib/Sema/IDETypeCheckingRequests.cpp b/lib/Sema/IDETypeCheckingRequests.cpp
index 901879a3141e1..e2d151c3d707e 100644
--- a/lib/Sema/IDETypeCheckingRequests.cpp
+++ b/lib/Sema/IDETypeCheckingRequests.cpp
@@ -143,7 +143,7 @@ static bool isExtensionAppliedInternal(const DeclContext *DC, Type BaseTy,
   // For check on specializable archetype see comment on
   // ContainsSpecializableArchetype.
   if (BaseTy->hasTypeVariable() || BaseTy->hasUnboundGenericType() ||
-      BaseTy->hasUnresolvedType() || BaseTy->hasError() ||
+      BaseTy->hasError() ||
       ContainsSpecializableArchetype::check(DC, BaseTy))
     return true;
 
@@ -181,7 +181,7 @@ static bool isMemberDeclAppliedInternal(const DeclContext *DC, Type BaseTy,
   // We can't leak type variables into another constraint system.
   // We can't do anything if the base type has unbound generic parameters.
   if (BaseTy->hasTypeVariable() || BaseTy->hasUnboundGenericType()||
-      BaseTy->hasUnresolvedType() || BaseTy->hasError())
+      BaseTy->hasError())
     return true;
 
   if (isa<TypeAliasDecl>(VD) && BaseTy->is<ProtocolType>()) {
diff --git a/lib/Sema/ImportResolution.cpp b/lib/Sema/ImportResolution.cpp
index 9f3f146324895..3c4f4325f4674 100644
--- a/lib/Sema/ImportResolution.cpp
+++ b/lib/Sema/ImportResolution.cpp
@@ -72,13 +72,15 @@ struct UnboundImport {
       importOrUnderlyingModuleDecl;
 
   NullablePtr<ImportDecl> getImportDecl() const {
-    return importOrUnderlyingModuleDecl.is<NullablePtr<ImportDecl>>() ?
-           importOrUnderlyingModuleDecl.get<NullablePtr<ImportDecl>>() : nullptr;
+    return isa<NullablePtr<ImportDecl>>(importOrUnderlyingModuleDecl)
+               ? cast<NullablePtr<ImportDecl>>(importOrUnderlyingModuleDecl)
+               : nullptr;
   }
 
   NullablePtr<ModuleDecl> getUnderlyingModule() const {
-    return importOrUnderlyingModuleDecl.is<ModuleDecl *>() ?
-           importOrUnderlyingModuleDecl.get<ModuleDecl *>() : nullptr;
+    return isa<ModuleDecl *>(importOrUnderlyingModuleDecl)
+               ? cast<ModuleDecl *>(importOrUnderlyingModuleDecl)
+               : nullptr;
   }
 
   /// Create an UnboundImport for a user-written import declaration.
@@ -161,6 +163,11 @@ class ImportResolver final : public DeclVisitor<ImportResolver> {
   /// The list of fully bound imports.
   SmallVector<AttributedImport<ImportedModule>, 16> boundImports;
 
+  /// Set of imported top-level clang modules. We normally don't expect
+  /// duplicated imports, but importing multiple submodules of the same clang
+  /// TLM would cause the same TLM to be imported once per submodule.
+  SmallPtrSet<const ModuleDecl*, 16> seenClangTLMs;
+
   /// All imported modules which should be considered when cross-importing.
   /// This is basically the transitive import graph, but with only top-level
   /// modules and without reexports from Objective-C modules.
@@ -190,6 +197,14 @@ class ImportResolver final : public DeclVisitor<ImportResolver> {
     addImplicitImports();
   }
 
+  // FIXME: Remove this ctor once namespace contents are imported to their
+  // corresponding module instead of the __ObjC module
+  ImportResolver(SourceFile &SF, ModuleDecl *explicitUnderlyingClangModule)
+      : SF(SF), ctx(SF.getASTContext()),
+        underlyingClangModule(explicitUnderlyingClangModule) {
+    addImplicitImports();
+  }
+
   void addImplicitImports();
 
   void addImplicitImport(ModuleDecl *module) {
@@ -320,26 +335,23 @@ void swift::performImportResolution(SourceFile &SF) {
 }
 
 void swift::performImportResolutionForClangMacroBuffer(
-    SourceFile &SF, ModuleDecl *clangModule
-) {
-  // If we've already performed import resolution, bail.
-  if (SF.ASTStage == SourceFile::ImportsResolved)
-    return;
-
-  ImportResolver resolver(SF);
-  resolver.addImplicitImport(clangModule);
-
-  // FIXME: This is a hack that we shouldn't need, but be sure that we can
-  // see the Swift standard library.
-  if (auto stdlib = SF.getASTContext().getStdlibModule())
-    resolver.addImplicitImport(stdlib);
+    SourceFile &SF, ModuleDecl *explicitOriginModule) {
+  assert(SF.ASTStage == SourceFile::Unprocessed);
 
+  // `getWrapperForModule` has already declared all the implicit clang module
+  // imports we need
+  ImportResolver resolver(SF, explicitOriginModule);
   SF.setImports(resolver.getFinishedImports());
   SF.setImportedUnderlyingModule(resolver.getUnderlyingClangModule());
 
   SF.ASTStage = SourceFile::ImportsResolved;
 }
 
+static bool isSubmodule(const ModuleDecl* M) {
+  auto clangMod = M->findUnderlyingClangModule();
+  return clangMod && clangMod->Parent;
+}
+
 //===----------------------------------------------------------------------===//
 // MARK: Import handling generally
 //===----------------------------------------------------------------------===//
@@ -387,14 +399,23 @@ void ImportResolver::bindImport(UnboundImport &&I) {
 
   I.validateOptions(topLevelModule, SF);
 
-  if (topLevelModule && topLevelModule != M) {
-    // If we have distinct submodule and top-level module, add both.
-    addImport(I, M);
-    addImport(I, topLevelModule.get());
-  }
-  else {
-    // Add only the import itself.
+  auto alreadyImportedTLM = [ID,this](const ModuleDecl *MD) {
+    ASSERT(!isSubmodule(MD));
+    // Scoped imports don't import all symbols from the module, so a scoped
+    // import does not count the module as imported
+    if (ID && isScopedImportKind(ID.get()->getImportKind()))
+      return false;
+    return !seenClangTLMs.insert(MD).second;
+  };
+  if (!M->isNonSwiftModule() || topLevelModule != M || !alreadyImportedTLM(M)) {
     addImport(I, M);
+    if (topLevelModule && topLevelModule != M &&
+        !alreadyImportedTLM(topLevelModule.get())) {
+      // If we have distinct submodule and top-level module, add both.
+      // Importing the submodule ensures that it gets loaded, but the decls
+      // are imported to the TLM, so import that for visibility.
+      addImport(I, topLevelModule.get());
+    }
   }
 
   crossImport(M, I);
@@ -572,8 +593,13 @@ ModuleImplicitImportsRequest::evaluate(Evaluator &evaluator,
       !clangImporter->importBridgingHeader(bridgingHeaderPath, module)) {
     auto *headerModule = clangImporter->getImportedHeaderModule();
     assert(headerModule && "Didn't load bridging header?");
-    imports.emplace_back(
+    AttributedImport<ImportedModule> import(
         ImportedModule(headerModule), SourceLoc(), ImportFlags::Exported);
+    if (ctx.ClangImporterOpts.BridgingHeaderIsInternal) {
+      import.accessLevel = AccessLevel::Internal;
+    }
+
+    imports.emplace_back(import);
   }
 
   // Implicitly import the underlying Clang half of this module if needed.
@@ -590,7 +616,18 @@ ModuleImplicitImportsRequest::evaluate(Evaluator &evaluator,
 }
 
 void ImportResolver::addImplicitImports() {
-  auto implicitImports = SF.getParentModule()->getImplicitImports();
+  // This is a workaround for the fact that namespaces are imported into the
+  // bridging header module. To allow correct lookup, we expose a ctor with an
+  // explicit underlying clang module input, which is the clang module that this
+  // macro expansion actually originates in.
+  const ModuleDecl *moduleToInherit = nullptr;
+  if (underlyingClangModule) {
+    moduleToInherit = underlyingClangModule;
+    boundImports.emplace_back(ImportedModule(underlyingClangModule));
+  } else {
+    moduleToInherit = SF.getParentModule();
+  }
+  auto implicitImports = moduleToInherit->getImplicitImports();
 
   // TODO: Support cross-module imports.
   for (auto &import : implicitImports.imports) {
@@ -906,8 +943,6 @@ void UnboundImport::validateResilience(NullablePtr<ModuleDecl> topLevelModule,
                                      targetName, importerName);
 
   if (ctx.LangOpts.hasFeature(Feature::InternalImportsByDefault)) {
-    // This will catch Swift 6 language mode as well where
-    // it will be reported as an error.
     inFlight.fixItRemove(import.accessLevelRange);
   } else {
     SourceRange attrRange = import.accessLevelRange;
@@ -915,12 +950,17 @@ void UnboundImport::validateResilience(NullablePtr<ModuleDecl> topLevelModule,
       inFlight.fixItReplace(attrRange, "internal");
     else
       inFlight.fixItInsert(import.importLoc, "internal ");
-
-    // Downgrade to warning only in pre-Swift 6 mode and
-    // when not using the experimental flag.
-    if (!ctx.LangOpts.hasFeature(Feature::AccessLevelOnImport))
-      inFlight.limitBehavior(DiagnosticBehavior::Warning);
   }
+
+  // Report as an error when InternalImportsByDefault is enabled or
+  // the experimental AccessLevelOnImport (but not Swift 6), only in libraries
+  // that are meant to be distributed.
+  auto featureEnabled =
+    ctx.LangOpts.hasFeature(Feature::AccessLevelOnImport) ||
+    ctx.LangOpts.hasFeature(Feature::InternalImportsByDefault);
+  if (!featureEnabled ||
+      SF.getParentModule()->getLibraryLevel() < LibraryLevel::SPI)
+    inFlight.limitBehavior(DiagnosticBehavior::Warning);
 }
 
 void UnboundImport::diagnoseInvalidAttr(DeclAttrKind attrKind,
@@ -1157,7 +1197,6 @@ CheckInconsistentAccessLevelOnImport::evaluate(
       error.fixItInsert(implicitImport->getStartLoc(),
                         diag::inconsistent_implicit_access_level_on_import_fixit,
                         otherAccessLevel);
-      error.flush();
       diags.diagnose(implicitImport,
                      diag::inconsistent_implicit_access_level_on_import_silence);
     }
@@ -1350,7 +1389,6 @@ ScopedImportLookupRequest::evaluate(Evaluator &evaluator,
 
     emittedDiag->fixItReplace(SourceRange(import->getKindLoc()),
                               getImportKindString(*actualKind));
-    emittedDiag->flush();
 
     if (decls.size() == 1)
       ctx.Diags.diagnose(decls.front(), diag::decl_declared_here,
@@ -1587,11 +1625,6 @@ void ImportResolver::findCrossImports(
   }
 }
 
-static bool isSubmodule(ModuleDecl* M) {
-  auto clangMod = M->findUnderlyingClangModule();
-  return clangMod && clangMod->Parent;
-}
-
 void ImportResolver::addCrossImportableModules(
     AttributedImport<ImportedModule> importDesc) {
   // FIXME: namelookup::getAllImports() doesn't quite do what we need (mainly
diff --git a/lib/Sema/LegalConstExprVerifier.cpp b/lib/Sema/LegalConstExprVerifier.cpp
new file mode 100644
index 0000000000000..76dee5ac9a9c9
--- /dev/null
+++ b/lib/Sema/LegalConstExprVerifier.cpp
@@ -0,0 +1,379 @@
+//===--------------------- LegalConstExprVerifier.cpp ---------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements syntactic validation that a `@const` expression
+// consists strictly of values and operations on those values as allowed
+// by the `@const` feature specification at this time.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MiscDiagnostics.h"
+#include "TypeChecker.h"
+#include "swift/AST/ASTContext.h"
+#include "swift/AST/ASTWalker.h"
+#include "swift/AST/ParameterList.h"
+#include "swift/AST/SemanticAttrs.h"
+#include "swift/Basic/Assertions.h"
+using namespace swift;
+
+namespace {
+static bool isIntegerType(Type type) {
+  return type->isInt() || type->isInt8() || type->isInt16() ||
+         type->isInt32() || type->isInt64() || type->isUInt() ||
+         type->isUInt8() || type->isUInt16() || type->isUInt32() ||
+         type->isUInt64();
+}
+
+static bool isFloatType(Type type) {
+  // TODO: CGFloat?
+  return type->isFloat() || type->isDouble() || type->isFloat80();
+}
+
+enum IllegalConstErrorDiagnosis {
+  TypeNotSupported,
+  AssociatedValue,
+  UnsupportedBinaryOperator,
+  UnsupportedUnaryOperator,
+  TypeExpression,
+  KeyPath,
+  Closue,
+  OpaqueDeclRef,
+  OpaqueFuncDeclRef,
+  NonConventionCFunc,
+  OpaqueCalleeRef,
+  NonConstParameter,
+  Default
+};
+
+/// Given a provided error expression \p errorExpr, and the reason
+/// \p reason for the failure, emit corresponding diagnostic.
+static void diagnoseError(const Expr *errorExpr,
+                          IllegalConstErrorDiagnosis reason,
+                          DiagnosticEngine &diags) {
+  SourceLoc errorLoc = errorExpr->getLoc();
+  switch (reason) {
+  case TypeNotSupported:
+    diags.diagnose(errorLoc, diag::const_unsupported_type);
+    break;
+  case AssociatedValue:
+    diags.diagnose(errorLoc, diag::const_unsupported_enum_associated_value);
+    break;
+  case UnsupportedBinaryOperator:
+    diags.diagnose(errorLoc, diag::const_unsupported_operator);
+    break;
+  case UnsupportedUnaryOperator:
+    diags.diagnose(errorLoc, diag::const_unsupported_operator);
+    break;
+  case TypeExpression:
+    diags.diagnose(errorLoc, diag::const_unsupported_type_expr);
+    break;
+  case KeyPath:
+    diags.diagnose(errorLoc, diag::const_unsupported_keypath);
+    break;
+  case Closue:
+    diags.diagnose(errorLoc, diag::const_unsupported_closure);
+    break;
+  case OpaqueDeclRef:
+    diags.diagnose(errorLoc, diag::const_opaque_decl_ref);
+    break;
+  case OpaqueFuncDeclRef:
+    diags.diagnose(errorLoc, diag::const_opaque_func_decl_ref);
+    break;
+  case NonConventionCFunc:
+    diags.diagnose(errorLoc, diag::const_non_convention_c_conversion);
+    break;
+  case OpaqueCalleeRef:
+    diags.diagnose(errorLoc, diag::const_opaque_callee);
+    break;
+  case NonConstParameter:
+    diags.diagnose(errorLoc, diag::const_non_const_param);
+    break;
+  case Default:
+    diags.diagnose(errorLoc, diag::const_unknown_default);
+    break;
+  }
+}
+
+static bool supportedOperator(const ApplyExpr *operatorApplyExpr) {
+  const auto operatorDeclRefExpr =
+      operatorApplyExpr->getFn()->getMemberOperatorRef();
+  if (!operatorDeclRefExpr)
+    return false;
+
+  // Non-stdlib operators are not allowed, for now
+  auto operatorDecl = operatorDeclRefExpr->getDecl();
+  if (!operatorDecl->getModuleContext()->isStdlibModule())
+    return false;
+
+  auto operatorName = operatorDecl->getBaseName();
+  if (!operatorName.isOperator())
+    return false;
+
+  auto operatorIdentifier = operatorName.getIdentifier();
+  if (!operatorIdentifier.isArithmeticOperator() &&
+      !operatorIdentifier.isBitwiseOperator() &&
+      !operatorIdentifier.isShiftOperator() &&
+      !operatorIdentifier.isStandardComparisonOperator())
+    return false;
+
+  // Operators which are not integer or floating point type are not
+  // allowed, for now.
+  auto operatorType = operatorApplyExpr->getType();
+  if (!isIntegerType(operatorType) && !isFloatType(operatorType))
+    return false;
+
+  return true;
+}
+
+static std::optional<std::pair<const Expr *, IllegalConstErrorDiagnosis>>
+checkSupportedInConst(const Expr *expr, const DeclContext *declContext) {
+  SmallVector<const Expr *, 4> expressionsToCheck;
+  expressionsToCheck.push_back(expr);
+  while (!expressionsToCheck.empty()) {
+    const Expr *expr = expressionsToCheck.pop_back_val();
+    // Lookthrough IdentityExpr, Tuple, Array, and InjectIntoOptional
+    // expressions.
+    if (const IdentityExpr *identityExpr = dyn_cast<IdentityExpr>(expr)) {
+      expressionsToCheck.push_back(identityExpr->getSubExpr());
+      continue;
+    }
+    if (const TupleExpr *tupleExpr = dyn_cast<TupleExpr>(expr)) {
+      for (const Expr *element : tupleExpr->getElements())
+        expressionsToCheck.push_back(element);
+      continue;
+    }
+    if (const ArrayExpr *arrayExpr = dyn_cast<ArrayExpr>(expr)) {
+      for (const Expr *element : arrayExpr->getElements())
+        expressionsToCheck.push_back(element);
+      continue;
+    }
+    if (const InjectIntoOptionalExpr *optionalExpr =
+            dyn_cast<InjectIntoOptionalExpr>(expr)) {
+      expressionsToCheck.push_back(optionalExpr->getSubExpr());
+      continue;
+    }
+
+    // Ensure that binary expressions consist of literals, references
+    // to other variables, and supported operators on integer and floating
+    // point types only.
+    if (const BinaryExpr *binaryExpr = dyn_cast<BinaryExpr>(expr)) {
+      if (!supportedOperator(binaryExpr))
+        return std::make_pair(binaryExpr, UnsupportedBinaryOperator);
+
+      expressionsToCheck.push_back(binaryExpr->getLHS());
+      expressionsToCheck.push_back(binaryExpr->getRHS());
+      continue;
+    }
+    if (const PrefixUnaryExpr *unaryExpr = dyn_cast<PrefixUnaryExpr>(expr)) {
+      if (!supportedOperator(unaryExpr))
+        return std::make_pair(unaryExpr, UnsupportedUnaryOperator);
+
+      expressionsToCheck.push_back(unaryExpr->getOperand());
+      continue;
+    }
+
+    // Literal expressions are okay
+    if (isa<LiteralExpr>(expr))
+      continue;
+
+    // Type expressions not supported in `@const` expressions
+    if (isa<TypeExpr>(expr))
+      return std::make_pair(expr, TypeExpression);
+
+    // Keypath expressions not supported in `@const` expressions for now
+    if (isa<KeyPathExpr>(expr))
+      return std::make_pair(expr, KeyPath);
+
+    // Closure expressions are not supported in `@const` expressions
+    // TODO: `@const`-evaluable closures
+    if (isa<AbstractClosureExpr>(expr))
+      return std::make_pair(expr, Closue);
+
+    // Function conversions, as long as the conversion is to a 'convention(c)'
+    // then consider the operand sub-expression
+    if (auto functionConvExpr = dyn_cast<FunctionConversionExpr>(expr)) {
+      if (auto targetFnTy =
+              functionConvExpr->getType()->getAs<AnyFunctionType>()) {
+        if (targetFnTy->getExtInfo().getRepresentation() ==
+            FunctionTypeRepresentation::CFunctionPointer) {
+          expressionsToCheck.push_back(functionConvExpr->getSubExpr());
+          continue;
+        } else {
+          return std::make_pair(expr, NonConventionCFunc);
+        }
+      }
+      return std::make_pair(expr, Default);
+    }
+
+    // Default argument expressions of a function must be ensured to be a
+    // constant by the definition of the function.
+    if (isa<DefaultArgumentExpr>(expr))
+      continue;
+
+    auto checkVarDecl = [&](const VarDecl *varDecl) -> bool {
+      // `@const` variables are always okay, their initializer expressions
+      // will be checked separately, individually.
+      if (varDecl->isConstValue())
+        return true;
+
+      // Non-explicitly-`@const` variables must have an initial value
+      // we can look through.
+      if (!varDecl->hasInitialValue())
+        return false;
+
+      if (auto initExpr = varDecl->getParentInitializer()) {
+        expressionsToCheck.push_back(initExpr);
+        return true;
+      }
+
+      return false;
+    };
+
+    auto checkFuncDecl = [&](const FuncDecl *funcDecl) -> bool {
+      if (funcDecl->hasBody() &&
+          funcDecl->getDeclContext()->getOutermostParentSourceFile() ==
+              declContext->getOutermostParentSourceFile())
+        return true;
+
+      return false;
+    };
+
+    // Look through to initial value expressions of memeber ref expressions
+    if (const MemberRefExpr *memberRef = dyn_cast<MemberRefExpr>(expr)) {
+      if (VarDecl *memberVarDecl =
+              dyn_cast<VarDecl>(memberRef->getMember().getDecl())) {
+        if (checkVarDecl(memberVarDecl))
+          continue;
+        return std::make_pair(expr, OpaqueDeclRef);
+      }
+      return std::make_pair(expr, OpaqueDeclRef);
+    }
+
+    // Look through to initial value expressions of decl ref expressions
+    if (const DeclRefExpr *declRef = dyn_cast<DeclRefExpr>(expr)) {
+      auto decl = declRef->getDecl();
+      // `@const` paramters are always okay
+      if (auto *paramDecl = dyn_cast<ParamDecl>(decl)) {
+        if (!paramDecl->isConstVal())
+          return std::make_pair(expr, NonConstParameter);
+        continue;
+      }
+
+      // function values
+      if (auto *funcDecl = dyn_cast<FuncDecl>(decl)) {
+        if (checkFuncDecl(funcDecl))
+          continue;
+        return std::make_pair(expr, OpaqueDeclRef);
+      }
+
+      if (const VarDecl *varDecl = dyn_cast<VarDecl>(declRef->getDecl())) {
+        if (checkVarDecl(varDecl))
+          continue;
+        return std::make_pair(expr, OpaqueDeclRef);
+      }
+      return std::make_pair(expr, OpaqueDeclRef);
+    }
+
+    // Otherwise only allow enum cases and function calls
+    if (!isa<ApplyExpr>(expr))
+      return std::make_pair(expr, Default);
+
+    const ApplyExpr *apply = cast<ApplyExpr>(expr);
+    ValueDecl *calledValue = apply->getCalledValue();
+    if (!calledValue)
+      return std::make_pair(expr, OpaqueCalleeRef);
+
+    // If this is an enum case, check that it does not have associated values
+    if (EnumElementDecl *enumCase = dyn_cast<EnumElementDecl>(calledValue)) {
+      if (enumCase->hasAssociatedValues())
+        return std::make_pair(expr, AssociatedValue);
+      continue;
+    }
+
+    // Explicitly support calls to `Int` and `Float` constructors
+    if (ConstructorRefCallExpr *initCallRef =
+            dyn_cast<ConstructorRefCallExpr>(apply->getSemanticFn())) {
+      if (auto type = initCallRef->getType()) {
+        if (auto *funcType = type->getAs<FunctionType>()) {
+          auto resultTy = funcType->getResult();
+          if (isIntegerType(resultTy) || isFloatType(resultTy)) {
+            assert(apply->getArgs()->size() == 1);
+            expressionsToCheck.push_back(apply->getArgs()->getExpr(0));
+            continue;
+          }
+        }
+      }
+    }
+
+    // TODO: calls to `@const` functions
+    //  AbstractFunctionDecl *callee =
+    //  dyn_cast<AbstractFunctionDecl>(calledValue); if (!callee)
+    //    return expr;
+    //  if (callee->isConstFunction()) {
+    //    for (auto arg : *apply->getArgs())
+    //      expressionsToCheck.push_back(arg.getExpr());
+    //  }
+
+    return std::make_pair(expr, Default);
+  }
+  return std::nullopt;
+}
+
+/// Given a call \c callExpr, if some or all of its arguments are required to be
+/// constants, check the argument expressions.
+static void verifyConstArguments(const CallExpr *callExpr,
+                                 const DeclContext *declContext) {
+  ValueDecl *calledDecl = callExpr->getCalledValue();
+  if (!calledDecl || !isa<AbstractFunctionDecl>(calledDecl))
+    return;
+  AbstractFunctionDecl *callee = cast<AbstractFunctionDecl>(calledDecl);
+  SmallVector<unsigned, 4> constArgumentIndices;
+  auto paramList = callee->getParameters();
+  for (unsigned i = 0; i < paramList->size(); ++i) {
+    ParamDecl *param = paramList->get(i);
+    if (param->isConstVal())
+      constArgumentIndices.push_back(i);
+  }
+  if (constArgumentIndices.empty())
+    return;
+
+  // Check that the arguments at the constArgumentIndices are all expressions
+  // consisting of @const-compatible constructs.
+  SmallVector<Expr *, 4> arguments;
+  for (auto arg : *callExpr->getArgs())
+    arguments.push_back(arg.getExpr());
+
+  for (unsigned constantIndex : constArgumentIndices) {
+    assert(constantIndex < arguments.size() &&
+           "constantIndex exceeds the number of arguments to the function");
+    if (auto error =
+            checkSupportedInConst(arguments[constantIndex], declContext)) {
+      diagnoseError(error->first, error->second,
+                    declContext->getASTContext().Diags);
+      declContext->getASTContext().Diags.diagnose(
+          arguments[constantIndex]->getLoc(),
+          diag::require_const_arg_for_parameter);
+    }
+  }
+}
+} // anonymous namespace
+
+void swift::diagnoseInvalidConstExpressions(const Expr *expr,
+                                            const DeclContext *declContext,
+                                            bool isConstInitExpr) {
+  if (isConstInitExpr) {
+    if (auto error = checkSupportedInConst(expr, declContext))
+      diagnoseError(error->first, error->second,
+                    declContext->getASTContext().Diags);
+  } else if (auto *callExpr = dyn_cast<CallExpr>(expr))
+    verifyConstArguments(callExpr, declContext);
+}
diff --git a/lib/Sema/LookupVisibleDecls.cpp b/lib/Sema/LookupVisibleDecls.cpp
index 80b6155ac732a..1890c683b744e 100644
--- a/lib/Sema/LookupVisibleDecls.cpp
+++ b/lib/Sema/LookupVisibleDecls.cpp
@@ -580,7 +580,7 @@ static void lookupVisibleCxxNamespaceMemberDecls(
             {});
 
         for (auto found : allResults) {
-          auto clangMember = found.get<clang::NamedDecl *>();
+          auto clangMember = cast<clang::NamedDecl *>(found);
           if (auto importedDecl =
                   ctx.getClangModuleLoader()->importDeclDirectly(
                       cast<clang::NamedDecl>(clangMember))) {
diff --git a/lib/Sema/MiscDiagnostics.cpp b/lib/Sema/MiscDiagnostics.cpp
index cf7a097021ca7..780ea16a13dc6 100644
--- a/lib/Sema/MiscDiagnostics.cpp
+++ b/lib/Sema/MiscDiagnostics.cpp
@@ -17,6 +17,7 @@
 #include "MiscDiagnostics.h"
 #include "TypeCheckAvailability.h"
 #include "TypeCheckConcurrency.h"
+#include "TypeCheckEmbedded.h"
 #include "TypeCheckInvertible.h"
 #include "TypeChecker.h"
 #include "swift/AST/ASTBridging.h"
@@ -30,6 +31,7 @@
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/NameLookupRequests.h"
 #include "swift/AST/Pattern.h"
+#include "swift/AST/PrettyStackTrace.h"
 #include "swift/AST/SemanticAttrs.h"
 #include "swift/AST/SourceFile.h"
 #include "swift/AST/Stmt.h"
@@ -40,6 +42,8 @@
 #include "swift/Basic/SourceManager.h"
 #include "swift/Basic/Statistic.h"
 #include "swift/Basic/StringExtras.h"
+#include "swift/ClangImporter/ClangImporter.h"
+#include "swift/ClangImporter/ClangImporterRequests.h"
 #include "swift/Parse/Lexer.h"
 #include "swift/Sema/ConstraintSystem.h"
 #include "swift/Sema/IDETypeChecking.h"
@@ -305,6 +309,11 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
         }
       }
 
+      // Performs checks on a closure.
+      if (auto *closure = dyn_cast<ClosureExpr>(E)) {
+        checkClosure(closure);
+      }
+
       // Specially diagnose some checked casts that are illegal.
       if (auto cast = dyn_cast<CheckedCastExpr>(E)) {
         checkCheckedCastExpr(cast);
@@ -343,8 +352,7 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
           if (auto asd = dyn_cast<AbstractStorageDecl>(decl)) {
             if (asd->getEffectfulGetAccessor()) {
               Ctx.Diags.diagnose(component.getLoc(),
-                                 diag::effectful_keypath_component,
-                                 asd->getDescriptiveKind(),
+                                 diag::effectful_keypath_component, asd,
                                  /*dynamic member lookup*/ false);
               Ctx.Diags.diagnose(asd->getLoc(), diag::kind_declared_here,
                                  asd->getDescriptiveKind());
@@ -383,6 +391,9 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
         }
       }
 
+      // Embedded Swift places restrictions on dynamic casting.
+      diagnoseDynamicCastInEmbedded(DC, cast);
+
       // now, look for conditional casts to marker protocols.
 
       if (!isa<ConditionalCheckedCastExpr>(cast) && !isa<IsExpr>(cast))
@@ -468,6 +479,11 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
             diag::copy_expression_cannot_be_used_with_noncopyable_types);
       }
 
+      /// FIXME: there really is no reason for the restriction on copy not being
+      ///   permitted on fields, other than needing tests to ensure it works.
+      if (Ctx.LangOpts.hasFeature(ManualOwnership))
+        return;
+
       // We only allow for copy_expr to be applied directly to lvalues. We do
       // not allow currently for it to be applied to fields.
       auto *subExpr = copyExpr->getSubExpr();
@@ -807,9 +823,7 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
         declParent = VD->getDeclContext()->getParentModule();
       }
 
-      Ctx.Diags.diagnose(DRE->getLoc(), diag::warn_unqualified_access,
-                         VD->getBaseIdentifier(),
-                         VD->getDescriptiveKind(),
+      Ctx.Diags.diagnose(DRE->getLoc(), diag::warn_unqualified_access, VD,
                          declParent);
       Ctx.Diags.diagnose(VD, diag::decl_declared_here, VD);
 
@@ -847,14 +861,13 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
         topLevelDiag = diag::fix_unqualified_access_top_level_multi;
 
       for (const ModuleValuePair &pair : sortedResults) {
-        DescriptiveDeclKind k = pair.second->getDescriptiveKind();
-
         SmallString<32> namePlusDot = pair.first->getName().str();
         namePlusDot.push_back('.');
 
-        Ctx.Diags.diagnose(DRE->getLoc(), topLevelDiag,
-                           namePlusDot, k, pair.first->getName())
-          .fixItInsert(DRE->getStartLoc(), namePlusDot);
+        Ctx.Diags
+            .diagnose(DRE->getLoc(), topLevelDiag, namePlusDot, pair.second,
+                      pair.first)
+            .fixItInsert(DRE->getStartLoc(), namePlusDot);
       }
     }
     
@@ -1459,6 +1472,33 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
         }
       }
     }
+
+    void checkClosure(ClosureExpr *closure) {
+      if (closure->isImplicit()) {
+        return;
+      }
+
+      auto attr = closure->getAttrs().getAttribute<ConcurrentAttr>();
+      if (!attr) {
+        return;
+      }
+
+      if (closure->getAsyncLoc().isValid()) {
+        return;
+      }
+
+      if (closure->getType()->castTo<AnyFunctionType>()->isAsync()) {
+        return;
+      }
+
+      // `@concurrent` is not allowed on synchronous closures, but this is
+      // likely to change, so diagnose this here, post solution application,
+      // instead of introducing an "implies `async`" inference rule that won't
+      // make sense in the nearish future.
+      Ctx.Diags.diagnose(attr->getLocation(),
+                         diag::execution_behavior_only_on_async_closure, attr);
+      attr->setInvalid();
+    }
   };
 
   DiagnoseWalker Walker(DC, isExprStmt);
@@ -1508,11 +1548,10 @@ DeferredDiags swift::findSyntacticErrorForConsume(
         break;
       }
       partial = true;
-      AccessStrategy strategy =
-          vd->getAccessStrategy(mre->getAccessSemantics(), AccessKind::Read,
-                                module, ResilienceExpansion::Minimal,
-                                /*useOldABI=*/false);
-      if (strategy.getKind() != AccessStrategy::Storage) {
+      auto isAccessedViaStorage = vd->isAccessedViaPhysicalStorage(
+          mre->getAccessSemantics(), AccessKind::Read, module,
+          ResilienceExpansion::Minimal);
+      if (!isAccessedViaStorage) {
         if (noncopyable) {
           result.emplace_back(loc, diag::consume_expression_non_storage);
           result.emplace_back(mre->getLoc(),
@@ -1753,15 +1792,34 @@ class ImplicitSelfUsageChecker : public BaseDiagnosticWalker {
       return false;
     }
 
-    // Require `LoadExpr`s when validating the self binding.
-    // This lets us reject invalid examples like:
-    //
-    //   let `self` = self ?? .somethingElse
-    //   guard let self = self else { return }
-    //   method() // <- implicit self is not allowed
-    //
-    return conditionalStmt->rebindsSelf(Ctx, /*requiresCaptureListRef*/ false,
-                                        /*requireLoadExpr*/ true);
+    if (Ctx.LangOpts.hasFeature(Feature::ImmutableWeakCaptures)) {
+      // Require that the RHS of the `let self = self` condition
+      // refers to a variable defined in a capture list.
+      // This lets us reject invalid examples like:
+      //
+      //   var `self` = self ?? .somethingElse
+      //   guard let self = self else { return }
+      //   method() // <- implicit self is not allowed
+      //
+      // In 5.10, instead of this check, compiler was checking that RHS of the
+      // self binding is loaded from a mutable variable. This is incorrect, but
+      // before immutable weak captures compiler was trying to maintain this
+      // behavior in Swift 5 mode for source compatibility. With immutable weak
+      // captures this does not work anymore, because even in Swift 5 mode there
+      // is no `LoadExpr` to use.
+      //
+      return conditionalStmt->rebindsSelf(Ctx, /*requiresCaptureListRef*/ true);
+    } else {
+      // Require `LoadExpr`s when validating the self binding.
+      // This lets us reject invalid examples like:
+      //
+      //   let `self` = self ?? .somethingElse
+      //   guard let self = self else { return }
+      //   method() // <- implicit self is not allowed
+      //
+      return conditionalStmt->rebindsSelf(Ctx, /*requiresCaptureListRef*/ false,
+                                          /*requireLoadExpr*/ true);
+    }
   }
 
   static bool
@@ -2244,11 +2302,12 @@ class ImplicitSelfUsageChecker : public BaseDiagnosticWalker {
         invalidImplicitSelfShouldOnlyWarn510(base, closure)) {
       warnUntilVersion.emplace(6);
     }
-    // Prior to Swift 7, downgrade to a warning if we're in a macro to preserve
-    // compatibility with the Swift 6 diagnostic behavior where we previously
-    // skipped diagnosing.
-    if (!Ctx.isSwiftVersionAtLeast(7) && isInMacro())
-      warnUntilVersion.emplace(7);
+    // Prior to the next language mode, downgrade to a warning if we're in a
+    // macro to preserve compatibility with the Swift 6 diagnostic behavior
+    // where we previously skipped diagnosing.
+    auto futureVersion = version::Version::getFutureMajorLanguageVersion();
+    if (!Ctx.isSwiftVersionAtLeast(futureVersion) && isInMacro())
+      warnUntilVersion.emplace(futureVersion);
 
     auto diag = Ctx.Diags.diagnose(loc, ID, std::move(Args)...);
     if (warnUntilVersion)
@@ -2697,8 +2756,10 @@ bool swift::diagnoseArgumentLabelError(ASTContext &ctx,
     }
   }
 
+  ASSERT((numMissing + numExtra + numWrong > 0) &&
+         "Should not call this function with nothing to diagnose");
+
   // Emit the diagnostic.
-  assert(numMissing > 0 || numExtra > 0 || numWrong > 0);
   llvm::SmallString<16> haveBuffer; // note: diagOpt has references to this
   llvm::SmallString<16> expectedBuffer; // note: diagOpt has references to this
 
@@ -3166,7 +3227,7 @@ bool swift::computeFixitsForOverriddenDeclaration(
 }
 
 //===----------------------------------------------------------------------===//
-// Per func/init diagnostics
+// MARK: Per func/init diagnostics
 //===----------------------------------------------------------------------===//
 
 namespace {
@@ -3333,9 +3394,9 @@ class VarDeclUsageChecker : public ASTWalker {
       // If this is a TopLevelCodeDecl, scan for global variables
       auto *body = TLCD->getBody();
       for (auto node : body->getElements()) {
-        if (node.is<Decl *>()) {
+        if (isa<Decl *>(node)) {
           // Flag all variables in a PatternBindingDecl
-          Decl *D = node.get<Decl *>();
+          Decl *D = cast<Decl *>(node);
           auto *PBD = dyn_cast<PatternBindingDecl>(D);
           if (!PBD) continue;
           for (auto idx : range(PBD->getNumPatternEntries())) {
@@ -3343,9 +3404,9 @@ class VarDeclUsageChecker : public ASTWalker {
               VarDecls[VD] = RK_Read|RK_Written|RK_Defined;
             });
           }
-        } else if (node.is<Stmt *>()) {
+        } else if (isa<Stmt *>(node)) {
           // Flag all variables in guard statements
-          Stmt *S = node.get<Stmt *>();
+          Stmt *S = cast<Stmt *>(node);
           auto *GS = dyn_cast<GuardStmt>(S);
           if (!GS) continue;
           for (StmtConditionElement SCE : GS->getCond()) {
@@ -3407,7 +3468,7 @@ class VarDeclUsageChecker : public ASTWalker {
 
     // Make sure that we setup our case body variables.
     if (auto *caseStmt = dyn_cast<CaseStmt>(S)) {
-      for (auto *vd : caseStmt->getCaseBodyVariablesOrEmptyArray()) {
+      for (auto *vd : caseStmt->getCaseBodyVariables()) {
         VarDecls[vd] |= RK_Defined;
       }
     }
@@ -3420,7 +3481,6 @@ class VarDeclUsageChecker : public ASTWalker {
 /// from its associated function body.
 class OpaqueUnderlyingTypeChecker : public ASTWalker {
   using Candidate = std::tuple<Expr *, SubstitutionMap, /*isUnique=*/bool>;
-  using AvailabilityContext = IfStmt *;
 
   ASTContext &Ctx;
   AbstractFunctionDecl *Implementation;
@@ -3430,16 +3490,16 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
   /// A set of all candidates with unique signatures.
   SmallPtrSet<const void *, 4> UniqueSignatures;
 
-  /// Represents a current availability context. `nullptr` means that
-  /// there are no restrictions.
-  AvailabilityContext CurrentAvailability = nullptr;
+  /// The active `IfStmt` that restricts availability. `nullptr` means that
+  /// there are is no restriction.
+  IfStmt *CurrentIfStmt = nullptr;
 
   /// All of the candidates together with their availability.
   ///
   /// If a candidate is found in non-`if #available` context or
   /// `if #available` has other dynamic conditions, it covers 'all'
   /// versions and the context is set to `nullptr`.
-  SmallVector<std::pair<AvailabilityContext, Candidate>, 4> Candidates;
+  SmallVector<std::pair<IfStmt *, Candidate>, 4> Candidates;
 
   bool HasInvalidReturn = false;
 
@@ -3525,14 +3585,40 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
       return;
     }
 
+    // Diagnose unsupported availability domains.
+    // FIXME: [availability] Support custom domains.
+    bool anyUnsupportedDomain = false;
+    for (const auto &entry : Candidates) {
+      IfStmt *stmt = entry.first;
+      if (!stmt) continue;
+
+      for (const auto &elt : stmt->getCond()) {
+        if (elt.getKind() != StmtConditionElement::CK_Availability)
+          continue;
+
+        auto poundAvailable = elt.getAvailability();
+        if (auto query = poundAvailable->getAvailabilityQuery()) {
+          if (query->getDomain().isCustom()) {
+            Ctx.Diags.diagnose(poundAvailable->getStartLoc(),
+                               diag::opaque_type_unsupported_availability,
+                               query->getDomain());
+            anyUnsupportedDomain = true;
+          }
+        }
+      }
+    }
+
+    if (anyUnsupportedDomain)
+      return;
+
     SmallVector<Candidate, 4> universallyUniqueCandidates;
 
     for (const auto &entry : Candidates) {
-      AvailabilityContext availability = entry.first;
+      IfStmt *stmt = entry.first;
       const auto &candidate = entry.second;
 
       // Unique candidate without availability context.
-      if (!availability && std::get<2>(candidate))
+      if (!stmt && std::get<2>(candidate))
         universallyUniqueCandidates.push_back(candidate);
     }
 
@@ -3602,29 +3688,6 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
     }
   }
 
-  bool isSelfReferencing(const Candidate &candidate) {
-    auto substitutions = std::get<1>(candidate);
-
-    // The underlying type can't be defined recursively
-    // in terms of the opaque type itself.
-    auto opaqueTypeInContext = Implementation->mapTypeIntoContext(
-        OpaqueDecl->getDeclaredInterfaceType());
-    for (auto genericParam : OpaqueDecl->getOpaqueGenericParams()) {
-      auto underlyingType = Type(genericParam).subst(substitutions);
-      auto isSelfReferencing = underlyingType.findIf(
-          [&](Type t) -> bool { return t->isEqual(opaqueTypeInContext); });
-
-      if (isSelfReferencing) {
-        Ctx.Diags.diagnose(std::get<0>(candidate)->getLoc(),
-                           diag::opaque_type_self_referential_underlying_type,
-                           underlyingType);
-        return true;
-      }
-    }
-
-    return false;
-  }
-
   // A single unique underlying substitution.
   void finalizeUnique(const Candidate &candidate) {
     // If we have one successful candidate, then save it as the underlying
@@ -3636,51 +3699,46 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
   // There is no clear winner here since there are candidates within
   // limited availability contexts.
   void finalizeOpaque(const Candidate &universallyAvailable) {
-    using AvailabilityCondition = OpaqueTypeDecl::AvailabilityCondition;
-
     SmallVector<OpaqueTypeDecl::ConditionallyAvailableSubstitutions *, 4>
         conditionalSubstitutions;
     SubstitutionMap universalSubstMap = std::get<1>(universallyAvailable);
 
     for (const auto &entry : Candidates) {
-      auto availabilityContext = entry.first;
+      auto stmt = entry.first;
       const auto &candidate = entry.second;
 
-      if (!availabilityContext)
+      if (!stmt)
         continue;
 
       unsigned neverAvailableCount = 0, alwaysAvailableCount = 0;
-      SmallVector<AvailabilityCondition, 4> conditions;
-
-      for (const auto &elt : availabilityContext->getCond()) {
-        auto condition = elt.getAvailability();
+      SmallVector<AvailabilityQuery, 4> queries;
 
-        auto availabilityRange = condition->getAvailableRange();
+      for (const auto &elt : stmt->getCond()) {
+        auto availabilityQuery = elt.getAvailability()->getAvailabilityQuery();
 
-        // Type checking did not set a range for this query (it may be invalid).
+        // Type checking did not populate this query (it may be invalid).
         // Treat the condition as if it were always true.
-        if (!availabilityRange.has_value()) {
+        if (!availabilityQuery) {
           alwaysAvailableCount++;
           continue;
         }
 
-        // If there is no lower endpoint it means that the condition has no
-        // OS version specification that matches the target platform.
-        // FIXME: [availability] Handle empty ranges (never available).
-        if (!availabilityRange->hasLowerEndpoint()) {
-          // An inactive #unavailable condition trivially evaluates to false.
-          if (condition->isUnavailability()) {
+        // If the query result is constant, then the corresponding type is
+        // either always available or never available at runtime.
+        if (auto constantResult = availabilityQuery->getConstantResult()) {
+          if (*constantResult) {
+            alwaysAvailableCount++;
+          } else {
             neverAvailableCount++;
-            continue;
           }
-
-          // An inactive #available condition trivially evaluates to true.
-          alwaysAvailableCount++;
           continue;
         }
 
-        conditions.push_back(
-            {*availabilityRange, condition->isUnavailability()});
+        // FIXME: [availability] Add support for custom domains.
+        auto domain = availabilityQuery->getDomain();
+        ASSERT(domain.isPlatform());
+
+        queries.push_back(*availabilityQuery);
       }
 
       // If there were any conditions that were always false, then this
@@ -3691,23 +3749,23 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
       // If all the conditions were trivially true, then this candidate is
       // effectively a universally available candidate and the rest of the
       // candidates should be ignored since they are unreachable.
-      if (alwaysAvailableCount == availabilityContext->getCond().size()) {
+      if (alwaysAvailableCount == stmt->getCond().size()) {
         universalSubstMap = std::get<1>(candidate);
         break;
       }
 
-      ASSERT(conditions.size() > 0);
+      ASSERT(queries.size() > 0);
 
       conditionalSubstitutions.push_back(
           OpaqueTypeDecl::ConditionallyAvailableSubstitutions::get(
-              Ctx, conditions,
+              Ctx, queries,
               std::get<1>(candidate).mapReplacementTypesOutOfContext()));
     }
 
     // Add universally available choice as the last one.
     conditionalSubstitutions.push_back(
         OpaqueTypeDecl::ConditionallyAvailableSubstitutions::get(
-            Ctx, {{VersionRange::all(), /*unavailable=*/false}},
+            Ctx, {AvailabilityQuery::universallyConstant(true)},
             universalSubstMap.mapReplacementTypesOutOfContext()));
 
     OpaqueDecl->setConditionallyAvailableSubstitutions(
@@ -3728,11 +3786,6 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
       auto candidate =
           std::make_tuple(underlyingToOpaque->getSubExpr(), subMap, isUnique);
 
-      if (isSelfReferencing(candidate)) {
-        HasInvalidReturn = true;
-        return Action::Stop();
-      }
-
       if (subMap.getRecursiveProperties().hasDynamicSelf()) {
         Ctx.Diags.diagnose(E->getLoc(),
                            diag::opaque_type_cannot_contain_dynamic_self);
@@ -3740,7 +3793,7 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
         return Action::Stop();
       }
 
-      Candidates.push_back({CurrentAvailability, candidate});
+      Candidates.push_back({CurrentIfStmt, candidate});
       return Action::SkipNode(E);
     }
 
@@ -3752,7 +3805,7 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
       if (Parent.getAsStmt() != Body) {
         // If this is not a top-level `if`, let's drop
         // contextual information that has been set previously.
-        CurrentAvailability = nullptr;
+        CurrentIfStmt = nullptr;
         return Action::Continue(S);
       }
 
@@ -3779,8 +3832,8 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
             // Note that we are about to walk into a return statement
             // that is located in a `if #available` without any other
             // conditions.
-            llvm::SaveAndRestore<AvailabilityContext> context(
-                CurrentAvailability, If);
+            llvm::SaveAndRestore<IfStmt *> context(
+                CurrentIfStmt, If);
 
             Return->getResult()->walk(*this);
           }
@@ -3815,71 +3868,6 @@ class OpaqueUnderlyingTypeChecker : public ASTWalker {
   }
 };
 
-class ReturnTypePlaceholderReplacer : public ASTWalker {
-  FuncDecl *Implementation;
-  BraceStmt *Body;
-  SmallVector<Type, 4> Candidates;
-
-  bool HasInvalidReturn = false;
-
-public:
-  ReturnTypePlaceholderReplacer(FuncDecl *Implementation, BraceStmt *Body)
-      : Implementation(Implementation), Body(Body) {}
-
-  void check() {
-    auto *resultRepr = Implementation->getResultTypeRepr();
-    if (!resultRepr) {
-      return;
-    }
-
-    Implementation->getASTContext()
-        .Diags
-        .diagnose(resultRepr->getLoc(),
-                  diag::placeholder_type_not_allowed_in_return_type)
-        .highlight(resultRepr->getSourceRange());
-
-    Body->walk(*this);
-
-    // If given function has any invalid returns in the body
-    // let's not try to validate the types, since it wouldn't
-    // be accurate.
-    if (HasInvalidReturn)
-      return;
-
-    auto writtenType = Implementation->getResultInterfaceType();
-    llvm::SmallPtrSet<TypeBase *, 8> seenTypes;
-    for (auto candidate : Candidates) {
-      if (!seenTypes.insert(candidate.getPointer()).second) {
-        continue;
-      }
-      TypeChecker::notePlaceholderReplacementTypes(writtenType, candidate);
-    }
-  }
-
-  MacroWalking getMacroWalkingBehavior() const override {
-    return MacroWalking::ArgumentsAndExpansion;
-  }
-
-  PreWalkResult<Expr *> walkToExprPre(Expr *E) override { return Action::Continue(E); }
-
-  PreWalkResult<Stmt *> walkToStmtPre(Stmt *S) override {
-    if (auto *RS = dyn_cast<ReturnStmt>(S)) {
-      if (RS->hasResult()) {
-        auto resultTy = RS->getResult()->getType();
-        HasInvalidReturn |= resultTy.isNull() || resultTy->hasError();
-        Candidates.push_back(resultTy);
-      }
-    }
-
-    return Action::Continue(S);
-  }
-
-  // Don't descend into nested decls.
-  PreWalkAction walkToDeclPre(Decl *D) override {
-    return Action::SkipNode();
-  }
-};
-
 } // end anonymous namespace
 
 SourceLoc swift::getFixItLocForVarToLet(VarDecl *var) {
@@ -3961,14 +3949,9 @@ VarDeclUsageChecker::~VarDeclUsageChecker() {
     if (!(access & RK_Defined))
       continue;
 
-    if (auto *caseStmt =
-            dyn_cast_or_null<CaseStmt>(var->getRecursiveParentPatternStmt())) {
-      // Only diagnose VarDecls from the first CaseLabelItem in CaseStmts, as
-      // the remaining items must match it anyway.
-      auto caseItems = caseStmt->getCaseLabelItems();
-      assert(!caseItems.empty() &&
-             "If we have any case stmt var decls, we should have a case item");
-      if (!caseItems.front().getPattern()->containsVarDecl(var))
+    if (isa_and_nonnull<CaseStmt>(var->getRecursiveParentPatternStmt())) {
+      // Only diagnose for the parent-most VarDecl.
+      if (var->getParentVarDecl())
         continue;
 
       auto *childVar = var->getCorrespondingCaseBodyVariable().get();
@@ -4009,9 +3992,12 @@ VarDeclUsageChecker::~VarDeclUsageChecker() {
     
     // If this variable has WeakStorageType, then it can be mutated in ways we
     // don't know.
-    if (var->getInterfaceType()->is<WeakStorageType>())
+    if (var->getInterfaceType()->is<WeakStorageType>() &&
+        (access & RK_CaptureList) &&
+        !DC->getASTContext().LangOpts.hasFeature(
+            Feature::ImmutableWeakCaptures))
       access |= RK_Written;
-    
+
     // Diagnose variables that were never used (other than their
     // initialization).
     //
@@ -4182,6 +4168,8 @@ VarDeclUsageChecker::~VarDeclUsageChecker() {
       if (isUsedInInactive(var))
         continue;
 
+      bool isWeak = var->getInterfaceType()->is<WeakStorageType>();
+
       // If this is a parameter explicitly marked 'var', remove it.
       if (FixItLoc.isInvalid()) {
         bool suggestCaseLet = false;
@@ -4192,10 +4180,14 @@ VarDeclUsageChecker::~VarDeclUsageChecker() {
           suggestCaseLet = isa<ForEachStmt>(stmt);
         }
         if (suggestCaseLet)
-          Diags.diagnose(var->getLoc(), diag::variable_tuple_elt_never_mutated,
+          Diags.diagnose(var->getLoc(),
+                         isWeak ? diag::weak_variable_tuple_elt_never_mutated
+                                : diag::variable_tuple_elt_never_mutated,
                          var->getName(), var->getNameStr());
         else
-          Diags.diagnose(var->getLoc(), diag::variable_never_mutated,
+          Diags.diagnose(var->getLoc(),
+                         isWeak ? diag::weak_variable_never_mutated
+                                : diag::variable_never_mutated,
                          var->getName(), true);
 
       }
@@ -4208,7 +4200,9 @@ VarDeclUsageChecker::~VarDeclUsageChecker() {
           suggestLet = !isa<ForEachStmt>(stmt);
         }
 
-        auto diag = Diags.diagnose(var->getLoc(), diag::variable_never_mutated,
+        auto diag = Diags.diagnose(var->getLoc(),
+                                   isWeak ? diag::weak_variable_never_mutated
+                                          : diag::variable_never_mutated,
                                    var->getName(), suggestLet);
 
         if (suggestLet)
@@ -4486,13 +4480,6 @@ void swift::performAbstractFuncDeclDiagnostics(AbstractFunctionDecl *AFD) {
         OpaqueUnderlyingTypeChecker(AFD, opaqueResultTy, body).check();
       }
     }
-  } else if (auto *FD = dyn_cast<FuncDecl>(AFD)) {
-    auto resultIFaceTy = FD->getResultInterfaceType();
-    // If the result has a placeholder, we need to try to use the contextual
-    // type inferred in the body to replace it.
-    if (resultIFaceTy && resultIFaceTy->hasPlaceholder()) {
-      ReturnTypePlaceholderReplacer(FD, body).check();
-    }
   }
 }
 
@@ -4979,6 +4966,8 @@ class ObjCSelectorWalker : public BaseDiagnosticWalker {
           case AccessorKind::Modify:
           case AccessorKind::Modify2:
           case AccessorKind::Init:
+          case AccessorKind::Borrow:
+          case AccessorKind::Mutate:
             llvm_unreachable("cannot be @objc");
           }
         } else {
@@ -5142,7 +5131,7 @@ static bool diagnoseAvailabilityCondition(PoundAvailableInfo *info,
       info->isUnavailability() ? "#unavailable" : "#available";
 
   bool hasValidSpecs = false;
-  bool allValidSpecsArePlatform = true;
+  bool wildcardRequiredInList = false;
   std::optional<SourceLoc> wildcardLoc;
   llvm::SmallSet<AvailabilityDomain, 8> seenDomains;
   for (auto spec : info->getSemanticAvailabilitySpecs(DC)) {
@@ -5155,6 +5144,7 @@ static bool diagnoseAvailabilityCondition(PoundAvailableInfo *info,
     auto domain = spec.getDomain();
     auto loc = parsedSpec->getStartLoc();
     bool hasVersion = !spec.getVersion().empty();
+    bool mustBeSpecifiedAlone = domain.mustBeSpecifiedAlone();
 
     if (!domain.supportsQueries()) {
       diags.diagnose(loc, diag::availability_query_not_allowed, domain,
@@ -5162,14 +5152,14 @@ static bool diagnoseAvailabilityCondition(PoundAvailableInfo *info,
       return true;
     }
 
-    if (!domain.isPlatform() && info->getQueries().size() > 1) {
+    if (mustBeSpecifiedAlone && info->getQueries().size() > 1) {
       diags.diagnose(loc, diag::availability_must_occur_alone, domain,
                      hasVersion);
       return true;
     }
 
+    auto rawVersion = parsedSpec->getRawVersion();
     if (hasVersion) {
-      auto rawVersion = parsedSpec->getRawVersion();
       if (!VersionRange::isValidVersion(rawVersion)) {
         diags
             .diagnose(loc, diag::availability_unsupported_version_number,
@@ -5184,6 +5174,12 @@ static bool diagnoseAvailabilityCondition(PoundAvailableInfo *info,
         diags.diagnose(loc, diag::avail_query_expected_version_number);
         return true;
       }
+
+      if (!domain.isVersionValid(rawVersion)) {
+        diags.diagnose(loc,
+                       diag::availability_invalid_version_number_for_domain,
+                       rawVersion, domain);
+      }
     } else if (hasVersion) {
       diags.diagnose(loc, diag::availability_unexpected_version, domain)
           .highlight(parsedSpec->getVersionSrcRange());
@@ -5197,9 +5193,15 @@ static bool diagnoseAvailabilityCondition(PoundAvailableInfo *info,
       return true;
     }
 
+    // Check the availability of the domain decl.
+    if (auto *domainDecl = spec.getDomain().getDecl()) {
+      auto where = ExportContext::forFunctionBody(DC, loc);
+      diagnoseDeclAvailability(domainDecl, loc, nullptr, where);
+    }
+
     hasValidSpecs = true;
-    if (!domain.isPlatform())
-      allValidSpecsArePlatform = false;
+    if (!mustBeSpecifiedAlone)
+      wildcardRequiredInList = true;
   }
 
   if (info->isUnavailability()) {
@@ -5209,7 +5211,7 @@ static bool diagnoseAvailabilityCondition(PoundAvailableInfo *info,
                     diag::unavailability_query_wildcard_not_required)
           .fixItRemove(*wildcardLoc);
     }
-  } else if (!wildcardLoc && hasValidSpecs && allValidSpecsArePlatform) {
+  } else if (!wildcardLoc && hasValidSpecs && wildcardRequiredInList) {
     if (info->getQueries().size() > 0) {
       auto insertLoc = info->getQueries().back()->getSourceRange().End;
       diags.diagnose(insertLoc, diag::availability_query_wildcard_required)
@@ -5604,7 +5606,7 @@ static void diagnoseUnintendedOptionalBehavior(const Expr *E,
               segment->getCalledValue(/*skipFunctionConversions=*/true), kind))
         if (auto firstArg =
                 getFirstArgIfUnintendedInterpolation(segment->getArgs(), kind))
-          diagnoseUnintendedInterpolation(firstArg, kind);
+          diagnoseUnintendedInterpolation(segment, firstArg, kind);
     }
 
     bool interpolationWouldBeUnintended(ConcreteDeclRef appendMethod,
@@ -5670,13 +5672,40 @@ static void diagnoseUnintendedOptionalBehavior(const Expr *E,
       return firstArg;
     }
 
-    void diagnoseUnintendedInterpolation(Expr * arg, UnintendedInterpolationKind kind) {
+    std::string baseInterpolationTypeName(CallExpr *segment) {
+      if (auto selfApplyExpr = dyn_cast<SelfApplyExpr>(segment->getFn())) {
+        auto baseType = selfApplyExpr->getBase()->getType();
+        return baseType->getWithoutSpecifierType()->getString();
+      }
+      return "unknown";
+    }
+    
+    void diagnoseUnintendedInterpolation(CallExpr *segment,
+                                         Expr * arg,
+                                         UnintendedInterpolationKind kind) {
       Ctx.Diags
           .diagnose(arg->getStartLoc(),
                     diag::debug_description_in_string_interpolation_segment,
                     (bool)kind)
           .highlight(arg->getSourceRange());
 
+      if (kind == UnintendedInterpolationKind::Optional) {
+        auto wrappedArgType = arg->getType()->getRValueType()->getOptionalObjectType();
+        auto baseTypeName = baseInterpolationTypeName(segment);
+        
+        // Suggest using a default value parameter, but only for non-string values
+        // when the base interpolation type is the default.
+        if (!wrappedArgType->isString() && baseTypeName == "DefaultStringInterpolation")
+          Ctx.Diags.diagnose(arg->getLoc(), diag::default_optional_parameter)
+            .highlight(arg->getSourceRange())
+            .fixItInsertAfter(arg->getEndLoc(), ", default: <#default value#>");
+
+        // Suggest providing a default value using the nil-coalescing operator.
+        Ctx.Diags.diagnose(arg->getLoc(), diag::default_optional_to_any)
+          .highlight(arg->getSourceRange())
+          .fixItInsertAfter(arg->getEndLoc(), " ?? <#default value#>");
+      }
+
       // Suggest 'String(describing: <expr>)'.
       auto argStart = arg->getStartLoc();
       Ctx.Diags
@@ -5686,13 +5715,6 @@ static void diagnoseUnintendedOptionalBehavior(const Expr *E,
           .highlight(arg->getSourceRange())
           .fixItInsert(argStart, "String(describing: ")
           .fixItInsertAfter(arg->getEndLoc(), ")");
-
-      if (kind == UnintendedInterpolationKind::Optional) {
-        // Suggest inserting a default value.
-        Ctx.Diags.diagnose(arg->getLoc(), diag::default_optional_to_any)
-          .highlight(arg->getSourceRange())
-          .fixItInsertAfter(arg->getEndLoc(), " ?? <#default value#>");
-      }
     }
 
     PreWalkResult<Expr *> walkToExprPre(Expr *E) override {
@@ -6247,9 +6269,9 @@ diagnoseDictionaryLiteralDuplicateKeyEntries(const Expr *E,
         note.fixItRemove(duplicated.first->getSourceRange());
         if (duplicatedEltIdx < commanLocs.size()) {
           note.fixItRemove(commanLocs[duplicatedEltIdx]);
-        } else {
+        } else if (!commanLocs.empty()) {
           // For the last element remove the previous comma.
-          note.fixItRemove(commanLocs[duplicatedEltIdx - 1]);
+          note.fixItRemove(commanLocs[commanLocs.size() - 1]);
         }
       };
 
@@ -6292,35 +6314,175 @@ static void diagnoseMissingMemberImports(const Expr *E, const DeclContext *DC) {
       if (auto declRef = E->getReferencedDecl())
         checkDecl(declRef.getDecl(), E->getLoc());
 
+      if (auto *KPE = dyn_cast<KeyPathExpr>(E)) {
+        for (const auto &component : KPE->getComponents()) {
+          if (component.hasDeclRef())
+            checkDecl(component.getDeclRef().getDecl(), component.getLoc(),
+                      /*downgradeToWarning=*/true);
+        }
+      }
+
       return Action::Continue(E);
     }
 
-    void checkDecl(const ValueDecl *decl, SourceLoc loc) {
+    void checkDecl(const ValueDecl *decl, SourceLoc loc,
+                   bool downgradeToWarning = false) {
       // Only diagnose uses of members.
       if (!decl->getDeclContext()->isTypeContext())
         return;
 
       if (!dc->isDeclImported(decl))
-        maybeDiagnoseMissingImportForMember(decl, dc, loc);
+        maybeDiagnoseMissingImportForMember(
+            decl, dc, loc,
+            downgradeToWarning ? DiagnosticBehavior::Warning
+                               : DiagnosticBehavior::Unspecified);
     }
   };
 
   auto &ctx = DC->getASTContext();
-  if (!ctx.LangOpts.hasFeature(Feature::MemberImportVisibility))
+  if (!ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                               /*allowMigration=*/true))
     return;
 
   DiagnoseWalker walker(DC);
   const_cast<Expr *>(E)->walk(walker);
 }
 
+static bool isReturningFRT(const clang::NamedDecl *ND,
+                           clang::QualType &outReturnType, ASTContext &Ctx) {
+  if (auto *FD = dyn_cast<clang::FunctionDecl>(ND))
+    outReturnType = FD->getReturnType();
+  else if (auto *MD = dyn_cast<clang::ObjCMethodDecl>(ND))
+    outReturnType = MD->getReturnType();
+  else
+    return false;
+
+  clang::QualType pointeeType = outReturnType;
+  if (outReturnType->isPointerType() || outReturnType->isReferenceType())
+    pointeeType = outReturnType->getPointeeType();
+
+  const auto *recordDecl = pointeeType->getAsRecordDecl();
+  if (!recordDecl)
+    return false;
+
+  return !importer::hasImmortalAttrs(recordDecl) &&
+         evaluateOrDefault(Ctx.evaluator,
+                           CxxRecordSemantics({recordDecl, Ctx, nullptr}),
+                           {}) == CxxRecordSemanticsKind::Reference;
+}
+
+static bool shouldDiagnoseMissingReturnsRetained(const clang::NamedDecl *ND,
+                                                 clang::QualType retType,
+                                                 ASTContext &Ctx) {
+  if (!Ctx.LangOpts.hasFeature(Feature::WarnUnannotatedReturnOfCxxFrt))
+    return false;
+
+  auto attrInfo = importer::ReturnOwnershipInfo(ND);
+  if (attrInfo.hasRetainAttr())
+    return false;
+
+  if (importer::matchSwiftAttrOnRecordPtr<bool>(
+          retType, {{"returned_as_unretained_by_default", true}}))
+    return false;
+
+  if (isa<clang::ObjCMethodDecl>(ND))
+    // All ObjCMethods can be annotated with ownership attrs
+    return true;
+
+  if (auto *FD = dyn_cast<clang::FunctionDecl>(ND)) {
+    if (isa<clang::CXXDeductionGuideDecl>(FD))
+      // Deduction guides don't need ownership attrs because they aren't
+      // functions.
+      return false;
+
+    if (const auto *methodDecl = dyn_cast<clang::CXXMethodDecl>(FD)) {
+      if (isa<clang::CXXConstructorDecl, clang::CXXDestructorDecl>(methodDecl))
+        // Ownership attrs are not yet supported for ctors and dtors if FRTs
+        return false;
+
+      if (methodDecl->isOverloadedOperator())
+        // Ownership attrs are not yet supported for overloaded operators
+        return false;
+
+      if (!methodDecl->isUserProvided())
+        // Implicitly defined methods don't need ownership attrs since users
+        // can't annotate them.
+        return false;
+    }
+
+    return true;
+  }
+
+  // Decls that aren't functions or ObjCMethods don't need ownership attrs.
+  return false;
+}
+
+// Diagnose calls to imported C++ functions that return `SWIFT_SHARED_REFERENCE`
+// types without explicit ownership annotations SWIFT_RETURNS_(UN)RETAINED
+static void diagnoseCxxFunctionCalls(const Expr *E, const DeclContext *DC) {
+  class DiagnoseWalker : public BaseDiagnosticWalker {
+    ASTContext &Ctx;
+
+  public:
+    explicit DiagnoseWalker(ASTContext &ctx) : Ctx(ctx) {}
+
+    PreWalkResult<Expr *> walkToExprPre(Expr *E) override {
+      if (!E)
+        return Action::SkipNode(E);
+
+      auto *CE = dyn_cast<CallExpr>(E);
+      if (!CE)
+        return Action::Continue(E);
+
+      auto *func = CE->getCalledValue(/*skipFunctionConversions=*/true);
+      if (!func)
+        return Action::Continue(E);
+
+      auto *clangDecl = func->getClangDecl();
+      if (!clangDecl)
+        return Action::Continue(E);
+
+      auto *ND = dyn_cast<clang::NamedDecl>(clangDecl);
+      if (!ND)
+        return Action::Continue(E);
+
+      clang::QualType retType;
+      if (!isReturningFRT(ND, retType, Ctx))
+        return Action::Continue(E);
+
+      if (shouldDiagnoseMissingReturnsRetained(ND, retType, Ctx)) {
+        SourceLoc diagnosticLoc = func->getLoc();
+        if (diagnosticLoc.isInvalid() && func->getClangDecl()) {
+          // Fixme: Remove the diagnosticLoc once the source locations of the
+          // objc method declarations are imported correctly.
+          diagnosticLoc = Ctx.getClangModuleLoader()->importSourceLocation(
+              ND->getLocation());
+        }
+
+        Ctx.Diags.diagnose(CE->getLoc(),
+                           diag::warn_unannotated_cxx_func_returning_frt, func);
+
+        Ctx.Diags.diagnose(diagnosticLoc,
+                           diag::note_unannotated_cxx_func_returning_frt, func);
+      }
+
+      return Action::Continue(E);
+    }
+  };
+
+  DiagnoseWalker walker(DC->getASTContext());
+  const_cast<Expr *>(E)->walk(walker);
+}
+
 //===----------------------------------------------------------------------===//
-// High-level entry points.
+// MARK: High-level entry points.
 //===----------------------------------------------------------------------===//
 
 /// Emit diagnostics for syntactic restrictions on a given expression.
 void swift::performSyntacticExprDiagnostics(const Expr *E,
                                             const DeclContext *DC,
-                                            bool isExprStmt) {
+                                            bool isExprStmt,
+                                            bool isConstInitExpr) {
   auto &ctx = DC->getASTContext();
   TypeChecker::diagnoseSelfAssignment(E);
   diagSyntacticUseRestrictions(E, DC, isExprStmt);
@@ -6337,9 +6499,13 @@ void swift::performSyntacticExprDiagnostics(const Expr *E,
   if (ctx.LangOpts.EnableObjCInterop)
     diagDeprecatedObjCSelectors(DC, E);
   diagnoseConstantArgumentRequirement(E, DC);
+  if (ctx.LangOpts.hasFeature(Feature::CompileTimeValues) &&
+      !ctx.LangOpts.hasFeature(Feature::CompileTimeValuesPreview))
+    diagnoseInvalidConstExpressions(E, DC, isConstInitExpr);
   diagUnqualifiedAccessToMethodNamedSelf(E, DC);
   diagnoseDictionaryLiteralDuplicateKeyEntries(E, DC);
   diagnoseMissingMemberImports(E, DC);
+  diagnoseCxxFunctionCalls(E, DC);
 }
 
 void swift::performStmtDiagnostics(const Stmt *S, DeclContext *DC) {
@@ -6360,12 +6526,12 @@ void swift::performStmtDiagnostics(const Stmt *S, DeclContext *DC) {
 }
 
 //===----------------------------------------------------------------------===//
-// Utility functions
+// MARK: Utility functions
 //===----------------------------------------------------------------------===//
 
 void swift::fixItAccess(InFlightDiagnostic &diag, ValueDecl *VD,
                         AccessLevel desiredAccess, bool isForSetter,
-                        bool shouldUseDefaultAccess) {
+                        bool shouldUseDefaultAccess, bool updateAttr) {
   StringRef fixItString;
   switch (desiredAccess) {
   case AccessLevel::Private:      fixItString = "private ";      break;
@@ -6380,27 +6546,35 @@ void swift::fixItAccess(InFlightDiagnostic &diag, ValueDecl *VD,
   AbstractAccessControlAttr *attr;
   if (isForSetter) {
     attr = attrs.getAttribute<SetterAccessAttr>();
-    cast<AbstractStorageDecl>(VD)->overwriteSetterAccess(desiredAccess);
+    if (updateAttr)
+      cast<AbstractStorageDecl>(VD)->overwriteSetterAccess(desiredAccess);
   } else {
     attr = attrs.getAttribute<AccessControlAttr>();
-    VD->overwriteAccess(desiredAccess);
+    if (updateAttr)
+      VD->overwriteAccess(desiredAccess);
 
     if (auto *ASD = dyn_cast<AbstractStorageDecl>(VD)) {
-      if (auto *getter = ASD->getAccessor(AccessorKind::Get))
-        getter->overwriteAccess(desiredAccess);
+      if (auto *getter = ASD->getAccessor(AccessorKind::Get)) {
+        if (updateAttr)
+          getter->overwriteAccess(desiredAccess);
+      }
 
       if (auto *setterAttr = attrs.getAttribute<SetterAccessAttr>()) {
         if (setterAttr->getAccess() > desiredAccess)
-          fixItAccess(diag, VD, desiredAccess, true);
+          fixItAccess(diag, VD, desiredAccess, /*isForSetter=*/true,
+                      /*shouldUseDefaultAccess=*/false, updateAttr);
       } else {
-        ASD->overwriteSetterAccess(desiredAccess);
+        if (updateAttr)
+          ASD->overwriteSetterAccess(desiredAccess);
       }
     }
   }
 
   if (isForSetter && VD->getFormalAccess() == desiredAccess) {
     assert(attr);
-    attr->setInvalid();
+    if (updateAttr)
+      attr->setInvalid();
+
     // Remove the setter attribute.
     diag.fixItRemove(attr->Range);
 
@@ -6420,7 +6594,8 @@ void swift::fixItAccess(InFlightDiagnostic &diag, ValueDecl *VD,
         // replace the "(set)" part of a setter attribute.
         diag.fixItReplace(attr->getLocation(), fixItString.drop_back());
       }
-      attr->setInvalid();
+      if (updateAttr)
+        attr->setInvalid();
     }
 
   } else if (auto *override = VD->getAttrs().getAttribute<OverrideAttr>()) {
@@ -6573,13 +6748,15 @@ TypeChecker::omitNeedlessWords(AbstractFunctionDecl *afd) {
   // Handle contextual type, result type, and returnsSelf.
   Type contextType = afd->getDeclContext()->getDeclaredInterfaceType();
   Type resultType;
-  bool returnsSelf = afd->hasDynamicSelfResult();
+  bool returnsSelf = false;
 
   if (auto func = dyn_cast<FuncDecl>(afd)) {
     resultType = func->getResultInterfaceType();
     resultType = func->mapTypeIntoContext(resultType);
+    returnsSelf = func->getResultInterfaceType()->hasDynamicSelfType();
   } else if (isa<ConstructorDecl>(afd)) {
     resultType = contextType;
+    returnsSelf = true;
   }
 
   // Figure out the first parameter name.
diff --git a/lib/Sema/MiscDiagnostics.h b/lib/Sema/MiscDiagnostics.h
index 36f24c71dfb3e..654afdd5b9ea7 100644
--- a/lib/Sema/MiscDiagnostics.h
+++ b/lib/Sema/MiscDiagnostics.h
@@ -41,7 +41,7 @@ namespace swift {
 
   /// Emit diagnostics for syntactic restrictions on a given expression.
   void performSyntacticExprDiagnostics(const Expr *E, const DeclContext *DC,
-                                       bool isExprStmt);
+                                       bool isExprStmt, bool isConstInitExpr);
 
   /// Emit diagnostics for a given statement.
   void performStmtDiagnostics(const Stmt *S, DeclContext *DC);
@@ -53,10 +53,10 @@ namespace swift {
 
   /// Emit a fix-it to set the access of \p VD to \p desiredAccess.
   ///
-  /// This actually updates \p VD as well.
+  /// This actually updates \p VD as well if \p updateAttr is true.
   void fixItAccess(InFlightDiagnostic &diag, ValueDecl *VD,
                    AccessLevel desiredAccess, bool isForSetter = false,
-                   bool shouldUseDefaultAccess = false);
+                   bool shouldUseDefaultAccess = false, bool updateAttr = true);
 
   /// Compute the location of the 'var' keyword for a 'var'-to-'let' Fix-It.
   SourceLoc getFixItLocForVarToLet(VarDecl *var);
@@ -101,6 +101,13 @@ namespace swift {
   void diagnoseConstantArgumentRequirement(const Expr *expr,
                                            const DeclContext *declContext);
 
+  /// If \p expr is a `@const` expression which contains values and
+  /// operations that are not legal in a `@const` expression,
+  /// emit an error diagnostic.
+  void diagnoseInvalidConstExpressions(const Expr *expr,
+                                       const DeclContext *declContext,
+                                       bool isConstInitExpr);
+
   /// Attempt to fix the type of \p decl so that it's a valid override for
   /// \p base...but only if we're highly confident that we know what the user
   /// should have written.
@@ -133,6 +140,9 @@ namespace swift {
   bool diagnoseUnhandledThrowsInAsyncContext(DeclContext *dc,
                                              ForEachStmt *forEach);
 
+  /// Determine if any of the performance hint diagnostics are enabled.
+  bool performanceHintDiagnosticsEnabled(ASTContext &ctx);
+
   class BaseDiagnosticWalker : public ASTWalker {
   protected:
     PreWalkAction walkToDeclPre(Decl *D) override {
diff --git a/lib/Sema/NonisolatedNonsendingByDefaultMigration.cpp b/lib/Sema/NonisolatedNonsendingByDefaultMigration.cpp
new file mode 100644
index 0000000000000..d0110e3f98efc
--- /dev/null
+++ b/lib/Sema/NonisolatedNonsendingByDefaultMigration.cpp
@@ -0,0 +1,304 @@
+//===-- Sema/NonisolatedNonsendingByDefaultMigration.cpp --------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file implements code migration support for the
+/// `NonisolatedNonsendingByDefault` feature.
+///
+//===----------------------------------------------------------------------===//
+
+#include "NonisolatedNonsendingByDefaultMigration.h"
+#include "swift/AST/ASTContext.h"
+#include "swift/AST/Decl.h"
+#include "swift/AST/DiagnosticsSema.h"
+#include "swift/AST/Expr.h"
+#include "swift/AST/Module.h"
+#include "swift/AST/ParameterList.h"
+#include "swift/AST/TypeRepr.h"
+#include "swift/Basic/Assertions.h"
+#include "swift/Basic/Feature.h"
+#include "swift/Basic/TaggedUnion.h"
+#include "llvm/ADT/PointerUnion.h"
+
+using namespace swift;
+
+namespace {
+class NonisolatedNonsendingByDefaultMigrationTarget {
+  ASTContext &ctx;
+  PointerUnion<ValueDecl *, AbstractClosureExpr *, FunctionTypeRepr *> node;
+  TaggedUnion<ActorIsolation, FunctionTypeIsolation> isolation;
+
+public:
+  NonisolatedNonsendingByDefaultMigrationTarget(ASTContext &ctx, ValueDecl *decl,
+                                      ActorIsolation isolation)
+      : ctx(ctx), node(decl), isolation(isolation) {}
+
+  NonisolatedNonsendingByDefaultMigrationTarget(ASTContext &ctx,
+                                      AbstractClosureExpr *closure,
+                                      ActorIsolation isolation)
+      : ctx(ctx), node(closure), isolation(isolation) {}
+
+  NonisolatedNonsendingByDefaultMigrationTarget(ASTContext &ctx, FunctionTypeRepr *repr,
+                                      FunctionTypeIsolation isolation)
+      : ctx(ctx), node(repr), isolation(isolation) {}
+
+  /// Warns that the behavior of nonisolated async functions will change under
+  /// `NonisolatedNonsendingByDefault` and suggests `@concurrent` to preserve the current
+  /// behavior.
+  void diagnose() const;
+};
+
+/// Determine whether the decl represents a test function that is
+/// annotated with `@Test` macro from the swift-testing framework.
+/// Such functions should be exempt from the migration because their
+/// execution is controlled by the framework and the change in
+/// behavior doesn't affect them.
+static bool isSwiftTestingTestFunction(ValueDecl *decl) {
+  if (!isa<FuncDecl>(decl))
+    return false;
+
+  return llvm::any_of(decl->getAttrs(), [&decl](DeclAttribute *attr) {
+    auto customAttr = dyn_cast<CustomAttr>(attr);
+    if (!customAttr)
+      return false;
+
+    auto *macro = decl->getResolvedMacro(customAttr);
+    return macro && macro->getBaseIdentifier().is("Test") &&
+           macro->getParentModule()->getName().is("Testing");
+  });
+}
+
+} // end anonymous namespace
+
+void NonisolatedNonsendingByDefaultMigrationTarget::diagnose() const {
+  const auto feature = Feature::NonisolatedNonsendingByDefault;
+
+  ASSERT(node);
+  ASSERT(ctx.LangOpts.getFeatureState(feature).isEnabledForMigration());
+
+  ValueDecl *decl = nullptr;
+  ClosureExpr *closure = nullptr;
+  FunctionTypeRepr *functionRepr = nullptr;
+
+  if ((decl = node.dyn_cast<ValueDecl *>())) {
+    // Diagnose only explicit nodes.
+    if (decl->isImplicit()) {
+      return;
+    }
+
+    // Only diagnose declarations from the current module.
+    if (decl->getModuleContext() != ctx.MainModule) {
+      return;
+    }
+
+    // `@Test` test-case have special semantics.
+    if (isSwiftTestingTestFunction(decl)) {
+      return;
+    }
+
+    // A special declaration that was either synthesized by the compiler
+    // or a macro expansion.
+    if (decl->getBaseName().hasDollarPrefix()) {
+      return;
+    }
+
+    // If the attribute cannot appear on this kind of declaration, we can't
+    // diagnose it.
+    if (!DeclAttribute::canAttributeAppearOnDecl(DeclAttrKind::Concurrent,
+                                                 decl)) {
+      return;
+    }
+
+    // For storage, make sure we have an explicit getter to diagnose.
+    if (auto *storageDecl = dyn_cast<AbstractStorageDecl>(decl)) {
+      if (!storageDecl->getParsedAccessor(AccessorKind::Get)) {
+        return;
+      }
+    }
+  } else if (auto *anyClosure = node.dyn_cast<AbstractClosureExpr *>()) {
+    // Diagnose only explicit nodes.
+    if (anyClosure->isImplicit()) {
+      return;
+    }
+
+    // The only subclass that can be explicit is this one.
+    closure = cast<ClosureExpr>(anyClosure);
+  } else {
+    functionRepr = cast<FunctionTypeRepr *>(node);
+  }
+
+  // The execution behavior changes only for nonisolated functions.
+  {
+    bool isNonisolated;
+    if (functionRepr) {
+      isNonisolated = isolation.get<FunctionTypeIsolation>().isNonIsolated();
+    } else {
+      auto isolation = this->isolation.get<ActorIsolation>();
+      isNonisolated = isolation.isNonisolated() || isolation.isUnspecified();
+    }
+
+    if (!isNonisolated) {
+      return;
+    }
+  }
+
+  // If the intended behavior is specified explicitly, don't diagnose.
+  {
+    const DeclAttributes *attrs = nullptr;
+    if (decl) {
+      attrs = &decl->getAttrs();
+    } else if (closure) {
+      attrs = &closure->getAttrs();
+    }
+
+    if (attrs) {
+      if (attrs->hasAttribute<ConcurrentAttr>())
+        return;
+
+      if (auto *nonisolated = attrs->getAttribute<NonisolatedAttr>()) {
+        if (nonisolated->isNonSending())
+          return;
+      }
+    }
+  }
+
+  // The execution behavior changes only for async functions.
+  {
+    bool isAsync = false;
+    if (decl) {
+      isAsync = decl->isAsync();
+    } else if (closure) {
+      isAsync = closure->isBodyAsync();
+    } else {
+      isAsync = functionRepr->isAsync();
+    }
+
+    if (!isAsync) {
+      return;
+    }
+  }
+
+  const ConcurrentAttr attr(/*implicit=*/true);
+
+  const auto featureName = feature.getName();
+  if (decl) {
+    // Diagnose the function, but slap the attribute on the storage declaration
+    // instead if the function is an accessor.
+    auto *functionDecl = dyn_cast<AbstractFunctionDecl>(decl);
+    if (!functionDecl) {
+      auto *storageDecl = cast<AbstractStorageDecl>(decl);
+
+      // This whole logic assumes that an 'async' storage declaration only has
+      // a getter. Yell for an update if this ever changes.
+      ASSERT(!storageDecl->getAccessor(AccessorKind::Set));
+
+      functionDecl = storageDecl->getParsedAccessor(AccessorKind::Get);
+    }
+
+    ctx.Diags
+        .diagnose(functionDecl->getLoc(),
+                  diag::attr_execution_nonisolated_behavior_will_change_decl,
+                  featureName, functionDecl)
+        .fixItInsertAttribute(
+            decl->getAttributeInsertionLoc(/*forModifier=*/false), &attr);
+  } else if (functionRepr) {
+    ctx.Diags
+        .diagnose(
+            functionRepr->getStartLoc(),
+            diag::attr_execution_nonisolated_behavior_will_change_typerepr,
+            featureName)
+        .fixItInsertAttribute(functionRepr->getStartLoc(), &attr);
+  } else {
+    auto diag = ctx.Diags.diagnose(
+        closure->getLoc(),
+        diag::attr_execution_nonisolated_behavior_will_change_closure,
+        featureName);
+    diag.fixItAddAttribute(&attr, closure);
+
+    // The following cases fail to compile together with `@concurrent` in
+    // Swift 5 or Swift 6 mode due to parser and type checker behaviors:
+    // 1. - Explicit parameter list
+    //    - Explicit result type
+    //    - No explicit `async` effect
+    // 2. - Explicit parenthesized parameter list
+    //    - No capture list
+    //    - No explicit result type
+    //    - No explicit effect
+    //
+    // Work around these issues by adding inferred effects together with the
+    // attribute.
+
+    // If there's an explicit `async` effect, we're good.
+    if (closure->getAsyncLoc().isValid()) {
+      return;
+    }
+
+    auto *params = closure->getParameters();
+    // FIXME: We need a better way to distinguish an implicit parameter list.
+    bool hasExplicitParenthesizedParamList =
+        params->getLParenLoc().isValid() &&
+        params->getLParenLoc() != closure->getStartLoc();
+
+    // If the parameter list is implicit, we're good.
+    if (!hasExplicitParenthesizedParamList) {
+      if (params->size() == 0) {
+        return;
+      } else if ((*params)[0]->isImplicit()) {
+        return;
+      }
+    }
+
+    // At this point we must proceed if there is an explicit result type.
+    // If there is both no explicit result type and the second case does not
+    // apply for any other reason, we're good.
+    if (!closure->hasExplicitResultType() &&
+        (!hasExplicitParenthesizedParamList ||
+         closure->getBracketRange().isValid() ||
+         closure->getThrowsLoc().isValid())) {
+      return;
+    }
+
+    // Compute the insertion location.
+    SourceLoc effectsInsertionLoc = closure->getThrowsLoc();
+    if (effectsInsertionLoc.isInvalid() && closure->hasExplicitResultType()) {
+      effectsInsertionLoc = closure->getArrowLoc();
+    }
+
+    if (effectsInsertionLoc.isInvalid()) {
+      effectsInsertionLoc = closure->getInLoc();
+    }
+
+    ASSERT(effectsInsertionLoc);
+
+    std::string fixIt = "async ";
+    if (closure->getThrowsLoc().isInvalid() && closure->isBodyThrowing()) {
+      fixIt += "throws ";
+    }
+
+    diag.fixItInsert(effectsInsertionLoc, fixIt);
+  }
+}
+
+void swift::warnAboutNewNonisolatedAsyncExecutionBehavior(
+    ASTContext &ctx, FunctionTypeRepr *repr, FunctionTypeIsolation isolation) {
+  NonisolatedNonsendingByDefaultMigrationTarget(ctx, repr, isolation).diagnose();
+}
+
+void swift::warnAboutNewNonisolatedAsyncExecutionBehavior(
+    ASTContext &ctx, ValueDecl *decl, ActorIsolation isolation) {
+  NonisolatedNonsendingByDefaultMigrationTarget(ctx, decl, isolation).diagnose();
+}
+
+void swift::warnAboutNewNonisolatedAsyncExecutionBehavior(
+    ASTContext &ctx, AbstractClosureExpr *closure, ActorIsolation isolation) {
+  NonisolatedNonsendingByDefaultMigrationTarget(ctx, closure, isolation).diagnose();
+}
diff --git a/lib/Sema/NonisolatedNonsendingByDefaultMigration.h b/lib/Sema/NonisolatedNonsendingByDefaultMigration.h
new file mode 100644
index 0000000000000..1e7b879c398ea
--- /dev/null
+++ b/lib/Sema/NonisolatedNonsendingByDefaultMigration.h
@@ -0,0 +1,53 @@
+//===-- Sema/NonisolatedNonsendingByDefaultMigration.h ----------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file provides code migration support for the
+/// `NonisolatedNonsendingByDefault` feature.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SEMA_NONISOLATEDNONSENDINGBYDEFAULTMIGRATION_H
+#define SWIFT_SEMA_NONISOLATEDNONSENDINGBYDEFAULTMIGRATION_H
+
+#include "swift/AST/ActorIsolation.h"
+#include "swift/AST/ExtInfo.h"
+
+namespace swift {
+
+class FunctionTypeRepr;
+class ValueDecl;
+class AbstractClosureExpr;
+
+/// Warns that the behavior of nonisolated async functions will change under
+/// `NonisolatedNonsendingByDefault` and suggests `@concurrent` to preserve the current
+/// behavior.
+void warnAboutNewNonisolatedAsyncExecutionBehavior(
+    ASTContext &ctx, FunctionTypeRepr *node, FunctionTypeIsolation isolation);
+
+/// Warns that the behavior of nonisolated async functions will change under
+/// `NonisolatedNonsendingByDefault` and suggests `@concurrent` to preserve the current
+/// behavior.
+void warnAboutNewNonisolatedAsyncExecutionBehavior(ASTContext &ctx,
+                                                   ValueDecl *node,
+                                                   ActorIsolation isolation);
+
+/// Warns that the behavior of nonisolated async functions will change under
+/// `NonisolatedNonsendingByDefault` and suggests `@concurrent` to preserve the current
+/// behavior.
+void warnAboutNewNonisolatedAsyncExecutionBehavior(ASTContext &ctx,
+                                                   AbstractClosureExpr *node,
+                                                   ActorIsolation isolation);
+
+} // end namespace swift
+
+#endif /* SWIFT_SEMA_NONISOLATEDNONSENDINGBYDEFAULTMIGRATION_H */
diff --git a/lib/Sema/OpenedExistentials.cpp b/lib/Sema/OpenedExistentials.cpp
index 21c8bff0b158c..4a39cf9f1b69f 100644
--- a/lib/Sema/OpenedExistentials.cpp
+++ b/lib/Sema/OpenedExistentials.cpp
@@ -291,9 +291,10 @@ findGenericParameterReferencesRec(CanGenericSignature genericSig,
 
   // Everything else should be a type parameter.
   if (!type->isTypeParameter()) {
-    llvm::errs() << "Unhandled type:\n";
-    type->dump(llvm::errs());
-    abort();
+    ABORT([&](auto &out) {
+      out << "Unhandled type:\n";
+      type->dump(out);
+    });
   }
 
   if (!type->getRootGenericParam()->isEqual(origParam)) {
@@ -316,7 +317,7 @@ findGenericParameterReferencesRec(CanGenericSignature genericSig,
         ASSERT(type->isEqual(origParam));
         return openedParam;
       },
-      MakeAbstractConformanceForGenericType());
+      LookUpConformanceInModule());
   }
 
   if (genericSig) {
@@ -463,7 +464,7 @@ static bool doesMemberHaveUnfulfillableConstraintsWithExistentialBase(
         [&](SubstitutableType *type) -> Type {
           return existentialSig.SelfType;
         },
-        MakeAbstractConformanceForGenericType());
+        LookUpConformanceInModule());
 
       // Make sure this is valid first.
       if (!existentialSig.OpenedSig->isValidTypeParameter(ty)) {
@@ -676,16 +677,6 @@ swift::canOpenExistentialCallArgument(ValueDecl *callee, unsigned paramIdx,
   if (!typeVar || !genericParam)
     return std::nullopt;
 
-  // Only allow opening the innermost generic parameters.
-  auto genericContext = callee->getAsGenericContext();
-  if (!genericContext || !genericContext->isGeneric())
-    return std::nullopt;
-
-  auto genericSig = callee->getInnermostDeclContext()
-      ->getGenericSignatureOfContext().getCanonicalSignature();
-  if (genericParam->getDepth() < genericSig->getMaxDepth())
-    return std::nullopt;
-
   // The binding could be an existential metatype. Get the instance type for
   // conformance checks and to build an opened existential signature. If the
   // instance type is not an existential type, i.e., the metatype is nested,
@@ -694,6 +685,28 @@ swift::canOpenExistentialCallArgument(ValueDecl *callee, unsigned paramIdx,
   if (!existentialTy->isExistentialType())
     return std::nullopt;
 
+  if (!canOpenExistentialAt(callee, paramIdx, genericParam, existentialTy))
+    return std::nullopt;
+
+  return std::pair(typeVar, bindingTy);
+}
+
+bool swift::canOpenExistentialAt(ValueDecl *callee, unsigned paramIdx,
+                                 GenericTypeParamType *genericParam,
+                                 Type existentialTy) {
+  ASSERT(existentialTy->isExistentialType());
+
+  // Only allow opening the innermost generic parameters.
+  auto genericContext = callee->getAsGenericContext();
+  if (!genericContext || !genericContext->isGeneric())
+    return false;
+
+  auto genericSig = callee->getInnermostDeclContext()
+                        ->getGenericSignatureOfContext()
+                        .getCanonicalSignature();
+  if (genericParam->getDepth() < genericSig->getMaxDepth())
+    return false;
+
   auto &ctx = callee->getASTContext();
 
   // If the existential argument conforms to all of protocol requirements on
@@ -714,7 +727,7 @@ swift::canOpenExistentialCallArgument(ValueDecl *callee, unsigned paramIdx,
     }
 
     if (!containsNonSelfConformance)
-      return std::nullopt;
+      return false;
   }
 
   auto existentialSig = ctx.getOpenedExistentialSignature(existentialTy);
@@ -725,10 +738,7 @@ swift::canOpenExistentialCallArgument(ValueDecl *callee, unsigned paramIdx,
       callee, existentialSig.OpenedSig, genericParam,
       existentialSig.SelfType->castTo<GenericTypeParamType>(),
       /*skipParamIdx=*/paramIdx);
-  if (referenceInfo.hasNonCovariantRef())
-    return std::nullopt;
-
-  return std::pair(typeVar, bindingTy);
+  return !referenceInfo.hasNonCovariantRef();
 }
 
 /// For each occurrence of a type **type** in `refTy` that satisfies
@@ -823,10 +833,11 @@ Type swift::typeEraseOpenedExistentialReference(
 
   auto applyOuterSubstitutions = [&](Type t) -> Type {
     if (t->hasTypeParameter()) {
-      auto outerSubs = existentialSig.Generalization;
-      unsigned depth = existentialSig.OpenedSig->getMaxDepth();
-      OuterSubstitutions replacer{outerSubs, depth};
-      return t.subst(replacer, replacer);
+      if (auto outerSubs = existentialSig.Generalization) {
+        unsigned depth = existentialSig.OpenedSig->getMaxDepth();
+        OuterSubstitutions replacer{outerSubs, depth};
+        return t.subst(replacer, replacer);
+      }
     }
 
     return t;
@@ -904,7 +915,7 @@ Type swift::typeEraseOpenedExistentialReference(
 
 Type swift::typeEraseOpenedArchetypesFromEnvironment(
     Type type, GenericEnvironment *env) {
-  assert(env->getKind() == GenericEnvironment::Kind::OpenedExistential);
+  ASSERT(env->getKind() == GenericEnvironment::Kind::Existential);
 
   return typeEraseExistentialSelfReferences(
       type,
diff --git a/lib/Sema/OpenedExistentials.h b/lib/Sema/OpenedExistentials.h
index 8475261b11dfe..8d748f57e9497 100644
--- a/lib/Sema/OpenedExistentials.h
+++ b/lib/Sema/OpenedExistentials.h
@@ -150,6 +150,13 @@ std::optional<std::pair<TypeVariableType *, Type>>
 canOpenExistentialCallArgument(ValueDecl *callee, unsigned paramIdx,
                                Type paramTy, Type argTy);
 
+/// A limited form of the check performed by \c canOpenExistentialCallArgument
+/// that assumes that a declaration where parameter came from, the parameter
+/// itself, and the types involved have been validated already.
+bool canOpenExistentialAt(ValueDecl *callee, unsigned paramIdx,
+                          GenericTypeParamType *genericParam,
+                          Type existentialTy);
+
 /// Given a type that includes an existential type that has been opened to
 /// the given type variable, replace the opened type variable and its member
 /// types with their upper bounds.
diff --git a/lib/Sema/PerformanceHints.cpp b/lib/Sema/PerformanceHints.cpp
new file mode 100644
index 0000000000000..79e110d68da92
--- /dev/null
+++ b/lib/Sema/PerformanceHints.cpp
@@ -0,0 +1,173 @@
+//===--------------------- PerformanceHints.cpp ---------------------------===//
+//
+// This source file is part of the Swift.org open source project
+
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This files implements the various checks/lints intended to provide
+// opt-in guidance for hidden costs in performance-critical Swift code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MiscDiagnostics.h"
+#include "swift/AST/ASTContext.h"
+#include "swift/AST/ASTWalker.h"
+#include "swift/AST/Decl.h"
+#include "swift/AST/DiagnosticsFrontend.h"
+#include "swift/AST/DiagnosticsSema.h"
+#include "swift/AST/Evaluator.h"
+#include "swift/AST/Expr.h"
+#include "swift/AST/TypeCheckRequests.h"
+#include "swift/AST/TypeVisitor.h"
+
+using namespace swift;
+
+bool swift::performanceHintDiagnosticsEnabled(ASTContext &ctx) {
+  return !ctx.Diags.isIgnoredDiagnostic(
+             diag::perf_hint_closure_returns_array.ID) ||
+         !ctx.Diags.isIgnoredDiagnostic(
+             diag::perf_hint_function_returns_array.ID) ||
+         !ctx.Diags.isIgnoredDiagnostic(
+             diag::perf_hint_param_expects_existential.ID) ||
+         !ctx.Diags.isIgnoredDiagnostic(
+             diag::perf_hint_func_returns_existential.ID) ||
+         !ctx.Diags.isIgnoredDiagnostic(
+             diag::perf_hint_closure_returns_existential.ID) ||
+         !ctx.Diags.isIgnoredDiagnostic(
+             diag::perf_hint_var_uses_existential.ID) ||
+         !ctx.Diags.isIgnoredDiagnostic(
+             diag::perf_hint_any_pattern_uses_existential.ID) ||
+         !ctx.Diags.isIgnoredDiagnostic(
+             diag::perf_hint_typealias_uses_existential.ID);
+}
+
+namespace {
+
+void checkImplicitCopyReturnType(const FuncDecl *FD, DiagnosticEngine &Diags) {
+  auto ReturnType = FD->getResultInterfaceType();
+  if (ReturnType->isArray() || ReturnType->isDictionary()) {
+    Diags.diagnose(FD->getLoc(), diag::perf_hint_function_returns_array, FD,
+                   ReturnType->isArray());
+  }
+}
+
+void checkImplicitCopyReturnType(const ClosureExpr *Closure,
+                                 DiagnosticEngine &Diags) {
+  auto ReturnType = Closure->getResultType();
+  if (ReturnType->isArray() || ReturnType->isDictionary()) {
+    Diags.diagnose(Closure->getLoc(), diag::perf_hint_closure_returns_array,
+                   ReturnType->isArray());
+  }
+}
+
+bool hasExistentialAnyInType(Type T) {
+  return T->getCanonicalType().findIf(
+      [](CanType CT) { return isa<ExistentialType>(CT); });
+}
+
+void checkExistentialInFunctionReturnType(const FuncDecl *FD,
+                                          DiagnosticEngine &Diags) {
+  Type T = FD->getResultInterfaceType();
+
+  if (hasExistentialAnyInType(T))
+    Diags.diagnose(FD, diag::perf_hint_func_returns_existential, FD);
+}
+
+void checkExistentialInClosureReturnType(const ClosureExpr *CE,
+                                         DiagnosticEngine &Diags) {
+  Type T = CE->getResultType();
+
+  if (hasExistentialAnyInType(T))
+    Diags.diagnose(CE->getLoc(), diag::perf_hint_closure_returns_existential);
+}
+
+void checkExistentialInVariableType(const VarDecl *VD,
+                                    DiagnosticEngine &Diags) {
+  Type T = VD->getInterfaceType();
+
+  if (hasExistentialAnyInType(T))
+    Diags.diagnose(VD, diag::perf_hint_var_uses_existential, VD);
+}
+
+void checkExistentialInPatternType(const AnyPattern *AP,
+                                   DiagnosticEngine &Diags) {
+  Type T = AP->getType();
+
+  if (hasExistentialAnyInType(T))
+    Diags.diagnose(AP->getLoc(), diag::perf_hint_any_pattern_uses_existential);
+}
+
+void checkExistentialInTypeAlias(const TypeAliasDecl *TAD,
+                                 DiagnosticEngine &Diags) {
+  Type T = TAD->getUnderlyingType();
+
+  if (hasExistentialAnyInType(T))
+    Diags.diagnose(TAD->getLoc(), diag::perf_hint_typealias_uses_existential,
+                   TAD);
+}
+
+/// Produce performance hint diagnostics for a SourceFile.
+class PerformanceHintDiagnosticWalker final : public ASTWalker {
+  ASTContext &Ctx;
+
+public:
+  PerformanceHintDiagnosticWalker(ASTContext &Ctx) : Ctx(Ctx) {}
+
+  static void check(SourceFile *SF) {
+    auto Walker = PerformanceHintDiagnosticWalker(SF->getASTContext());
+    SF->walk(Walker);
+  }
+
+  PostWalkResult<Pattern *> walkToPatternPost(Pattern *P) override {
+    if (P->isImplicit())
+      return Action::Continue(P);
+
+    if (const AnyPattern *AP = dyn_cast<AnyPattern>(P)) {
+      checkExistentialInPatternType(AP, Ctx.Diags);
+    }
+
+    return Action::Continue(P);
+  }
+
+  PostWalkResult<Expr *> walkToExprPost(Expr *E) override {
+    if (E->isImplicit())
+      return Action::Continue(E);
+
+    if (const ClosureExpr *CE = dyn_cast<ClosureExpr>(E)) {
+      checkImplicitCopyReturnType(CE, Ctx.Diags);
+      checkExistentialInClosureReturnType(CE, Ctx.Diags);
+    }
+
+    return Action::Continue(E);
+  }
+
+  PostWalkAction walkToDeclPost(Decl *D) override {
+    if (D->isImplicit())
+      return Action::Continue();
+
+    if (const FuncDecl *FD = dyn_cast<FuncDecl>(D)) {
+      checkImplicitCopyReturnType(FD, Ctx.Diags);
+      checkExistentialInFunctionReturnType(FD, Ctx.Diags);
+    } else if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
+      checkExistentialInVariableType(VD, Ctx.Diags);
+    } else if (const TypeAliasDecl *TAD = dyn_cast<TypeAliasDecl>(D)) {
+      checkExistentialInTypeAlias(TAD, Ctx.Diags);
+    }
+
+    return Action::Continue();
+  }
+};
+} // namespace
+
+evaluator::SideEffect EmitPerformanceHints::evaluate(Evaluator &evaluator,
+                                                     SourceFile *SF) const {
+  PerformanceHintDiagnosticWalker::check(SF);
+  return {};
+}
diff --git a/lib/Sema/PlaygroundTransform.cpp b/lib/Sema/PlaygroundTransform.cpp
index 997e0d1aca68d..44ac0531c2526 100644
--- a/lib/Sema/PlaygroundTransform.cpp
+++ b/lib/Sema/PlaygroundTransform.cpp
@@ -821,9 +821,9 @@ class Instrumenter : InstrumenterBase {
     if (auto *VD = dyn_cast_or_null<ValueDecl>(node.dyn_cast<Decl *>())) {
       auto interfaceTy = VD->getInterfaceType();
       auto contextualTy = VD->getInnermostDeclContext()->mapTypeIntoContext(interfaceTy);
-      return !contextualTy->isNoncopyable();
+      return contextualTy->isCopyable();
     } else if (auto *E = node.dyn_cast<Expr *>()) {
-      return !E->getType()->isNoncopyable();
+      return E->getType()->isCopyable();
     } else {
       return true;
     }
diff --git a/lib/Sema/PreCheckTarget.cpp b/lib/Sema/PreCheckTarget.cpp
index 0336f1f0636e0..0c598db8155b2 100644
--- a/lib/Sema/PreCheckTarget.cpp
+++ b/lib/Sema/PreCheckTarget.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,7 +11,8 @@
 //===----------------------------------------------------------------------===//
 //
 // Pre-checking resolves unqualified name references, type expressions and
-// operators.
+// operators. Target in this context refers to `SyntacticElementTarget`, which
+// is a unit of type-checking.
 //
 //===----------------------------------------------------------------------===//
 
@@ -518,11 +519,12 @@ diagnoseUnqualifiedInit(UnresolvedDeclRefExpr *initExpr, DeclContext *dc,
                         initExpr->getNameLoc(), /*implicit=*/true);
 }
 
-/// Bind an UnresolvedDeclRefExpr by performing name lookup and
-/// returning the resultant expression. Context is the DeclContext used
-/// for the lookup.
-Expr *TypeChecker::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
-                                      DeclContext *DC) {
+/// Bind an UnresolvedDeclRefExpr by performing name lookup using the given
+/// options and returning the resultant expression. `DC` is the DeclContext
+/// used for the lookup. If the lookup doesn't find any results, returns
+/// `nullptr`.
+static Expr *resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE, DeclContext *DC,
+                                NameLookupOptions lookupOptions) {
   auto &Context = DC->getASTContext();
   DeclNameRef Name = UDRE->getName();
   SourceLoc Loc = UDRE->getLoc();
@@ -562,13 +564,6 @@ Expr *TypeChecker::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
     LookupName = DeclNameRef(lookupName);
   }
 
-  // Perform standard value name lookup.
-  NameLookupOptions lookupOptions = defaultUnqualifiedLookupOptions;
-  // TODO: Include all of the possible members to give a solver a
-  //       chance to diagnose name shadowing which requires explicit
-  //       name/module qualifier to access top-level name.
-  lookupOptions |= NameLookupFlags::IncludeOuterResults;
-
   LookupResult Lookup;
 
   bool AllDeclRefs = true;
@@ -627,17 +622,8 @@ Expr *TypeChecker::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
   }
 
   if (!Lookup) {
-    // If we failed lookup of an operator, check to see if this is a range
-    // operator misspelling. Otherwise try to diagnose a juxtaposition
-    // e.g. (x*-4) that needs whitespace.
-    if (diagnoseRangeOperatorMisspell(Context.Diags, UDRE) ||
-        diagnoseIncDecOperator(Context.Diags, UDRE) ||
-        diagnoseOperatorJuxtaposition(UDRE, DC) ||
-        diagnoseNonexistentPowerOperator(Context.Diags, UDRE, DC)) {
-      return errorResult();
-    }
-
-    // Try ignoring access control.
+    // For the purpose of diagnosing inaccessible results, try the lookup again
+    // but ignore access control.
     NameLookupOptions relookupOptions = lookupOptions;
     relookupOptions |= NameLookupFlags::IgnoreAccessControl;
     auto inaccessibleResults =
@@ -662,135 +648,21 @@ Expr *TypeChecker::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
       return errorResult();
     }
 
-    // Try ignoring missing imports.
-    relookupOptions |= NameLookupFlags::IgnoreMissingImports;
-    auto nonImportedResults =
-        TypeChecker::lookupUnqualified(DC, LookupName, Loc, relookupOptions);
-    if (nonImportedResults) {
-      const ValueDecl *first = nonImportedResults.front().getValueDecl();
-      maybeDiagnoseMissingImportForMember(first, DC, Loc);
-
-      // Don't try to recover here; we'll get more access-related diagnostics
-      // downstream if the type of the inaccessible decl is also inaccessible.
-      return errorResult();
-    }
-
-    // TODO: Name will be a compound name if it was written explicitly as
-    // one, but we should also try to propagate labels into this.
-    DeclNameLoc nameLoc = UDRE->getNameLoc();
-
-    Identifier simpleName = Name.getBaseIdentifier();
-    const char *buffer = simpleName.get();
-    llvm::SmallString<64> expectedIdentifier;
-    bool isConfused = false;
-    uint32_t codepoint;
-    uint32_t firstConfusableCodepoint = 0;
-    int totalCodepoints = 0;
-    int offset = 0;
-    while ((codepoint = validateUTF8CharacterAndAdvance(buffer,
-                                                        buffer +
-                                                        strlen(buffer)))
-           != ~0U) {
-      int length = (buffer - simpleName.get()) - offset;
-      if (auto expectedCodepoint =
-          confusable::tryConvertConfusableCharacterToASCII(codepoint)) {
-        if (firstConfusableCodepoint == 0) {
-          firstConfusableCodepoint = codepoint;
-        }
-        isConfused = true;
-        expectedIdentifier += expectedCodepoint;
-      } else {
-        expectedIdentifier += (char)codepoint;
-      }
-
-      totalCodepoints++;
-
-      offset += length;
-    }
-
-    auto emitBasicError = [&] {
-      
-      if (Name.isSimpleName(Context.Id_self)) {
-        // `self` gets diagnosed with a different error when it can't be found.
-        Context.Diags
-            .diagnose(Loc, diag::cannot_find_self_in_scope)
-            .highlight(UDRE->getSourceRange());
-      } else {
-        Context.Diags
-            .diagnose(Loc, diag::cannot_find_in_scope, Name,
-                      Name.isOperator())
-            .highlight(UDRE->getSourceRange());
-      }
-
-      if (!Context.LangOpts.DisableExperimentalClangImporterDiagnostics) {
-        Context.getClangModuleLoader()->diagnoseTopLevelValue(
-            Name.getFullName());
-      }
-    };
-
-    if (!isConfused) {
-      if (Name.isSimpleName(Context.Id_Self)) {
-        if (DeclContext *typeContext = DC->getInnermostTypeContext()){
-          Type SelfType = typeContext->getSelfInterfaceType();
-
-          if (typeContext->getSelfClassDecl() &&
-              !typeContext->getSelfClassDecl()->isForeignReferenceType())
-            SelfType = DynamicSelfType::get(SelfType, Context);
-          return new (Context)
-              TypeExpr(new (Context) SelfTypeRepr(SelfType, Loc));
-        }
-      }
-
-      TypoCorrectionResults corrections(Name, nameLoc);
-
-      // FIXME: Don't perform typo correction inside macro arguments, because it
-      // will invoke synthesizing declarations in this scope, which will attempt to
-      // expand this macro which leads to circular reference errors.
-      if (!namelookup::isInMacroArgument(DC->getParentSourceFile(), UDRE->getLoc())) {
-        TypeChecker::performTypoCorrection(DC, UDRE->getRefKind(), Type(),
-                                           lookupOptions, corrections);
-      }
-
-      if (auto typo = corrections.claimUniqueCorrection()) {
-        auto diag = Context.Diags.diagnose(
-            Loc, diag::cannot_find_in_scope_corrected, Name,
-            Name.isOperator(), typo->CorrectedName.getBaseIdentifier().str());
-        diag.highlight(UDRE->getSourceRange());
-        typo->addFixits(diag);
-      } else {
-        emitBasicError();
-      }
-
-      corrections.noteAllCandidates();
-    } else {
-      emitBasicError();
-
-      if (totalCodepoints == 1) {
-        auto charNames = confusable::getConfusableAndBaseCodepointNames(
-            firstConfusableCodepoint);
-        Context.Diags
-            .diagnose(Loc, diag::single_confusable_character,
-                      UDRE->getName().isOperator(), simpleName.str(),
-                      charNames.first, expectedIdentifier, charNames.second)
-            .fixItReplace(Loc, expectedIdentifier);
-      } else {
-        Context.Diags
-            .diagnose(Loc, diag::confusable_character,
-                      UDRE->getName().isOperator(), simpleName.str(),
-                      expectedIdentifier)
-            .fixItReplace(Loc, expectedIdentifier);
-      }
-    }
-
-    // TODO: consider recovering from here.  We may want some way to suppress
-    // downstream diagnostics, though.
-
-    return errorResult();
+    // No results were found.
+    return nullptr;
   }
 
   // FIXME: Need to refactor the way we build an AST node from a lookup result!
 
   auto buildTypeExpr = [&](TypeDecl *D) -> Expr * {
+    auto *LookupDC = Lookup[0].getDeclContext();
+
+    // If the type decl is a member that wasn't imported, diagnose it now when
+    // MemberImportVisibility is enabled.
+    if (!UDRE->isImplicit() && LookupDC)
+      maybeDiagnoseMissingImportForMember(D, LookupDC,
+                                          UDRE->getNameLoc().getStartLoc());
+
     // FIXME: This is odd.
     if (isa<ModuleDecl>(D)) {
       return new (Context) DeclRefExpr(
@@ -798,7 +670,6 @@ Expr *TypeChecker::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
           /*Implicit=*/false, AccessSemantics::Ordinary, D->getInterfaceType());
     }
 
-    auto *LookupDC = Lookup[0].getDeclContext();
     bool makeTypeValue = false;
 
     if (isa<GenericTypeParamDecl>(D) &&
@@ -817,8 +688,7 @@ Expr *TypeChecker::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
                    : D->getInterfaceType());
     } else {
       if (makeTypeValue) {
-        return TypeValueExpr::createForDecl(UDRE->getNameLoc(),
-                                            cast<GenericTypeParamDecl>(D));
+        return TypeValueExpr::createForDecl(UDRE->getNameLoc(), D, LookupDC);
       } else {
         return TypeExpr::createForDecl(UDRE->getNameLoc(), D, LookupDC);
       }
@@ -891,8 +761,16 @@ Expr *TypeChecker::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
           DC, UDRE->getNameLoc().getBaseNameLoc(), ResultValues);
     }
 
-    return buildRefExpr(ResultValues, DC, UDRE->getNameLoc(),
-                        UDRE->isImplicit(), UDRE->getFunctionRefInfo());
+    // If there is a single result and it's a member that wasn't imported,
+    // diagnose it now when MemberImportVisibility is enabled.
+    if (ResultValues.size() == 1) {
+      maybeDiagnoseMissingImportForMember(ResultValues.front(), DC,
+                                          UDRE->getNameLoc().getStartLoc());
+    }
+
+    return TypeChecker::buildRefExpr(ResultValues, DC, UDRE->getNameLoc(),
+                                     UDRE->isImplicit(),
+                                     UDRE->getFunctionRefInfo());
   }
 
   ResultValues.clear();
@@ -982,6 +860,157 @@ Expr *TypeChecker::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
   return errorResult();
 }
 
+Expr *TypeChecker::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
+                                      DeclContext *DC) {
+  auto &Context = DC->getASTContext();
+
+  // Perform standard value name lookup.
+  NameLookupOptions lookupOptions = defaultUnqualifiedLookupOptions;
+  // TODO: Include all of the possible members to give a solver a
+  //       chance to diagnose name shadowing which requires explicit
+  //       name/module qualifier to access top-level name.
+  lookupOptions |= NameLookupFlags::IncludeOuterResults;
+
+  Expr *result = ::resolveDeclRefExpr(UDRE, DC, lookupOptions);
+  if (!result && Context.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                                             /*allowMigration=*/true)) {
+    // If we didn't find a result, try again but this time relax
+    // MemberImportVisibility restrictions. Note that diagnosing the missing
+    // import is already handled by resolveDeclRefExpr().
+    lookupOptions |= NameLookupFlags::IgnoreMissingImports;
+    result = ::resolveDeclRefExpr(UDRE, DC, lookupOptions);
+  }
+
+  if (result)
+    return result;
+
+  // We didn't find any results. Look for common mistakes to diagnose.
+  DeclNameRef Name = UDRE->getName();
+  SourceLoc Loc = UDRE->getLoc();
+  if (Loc.isInvalid())
+    DC = DC->getModuleScopeContext();
+
+  auto errorResult = [&]() -> Expr * {
+    return new (Context) ErrorExpr(UDRE->getSourceRange());
+  };
+
+  // If we failed lookup of an operator, check to see if this is a range
+  // operator misspelling. Otherwise try to diagnose a juxtaposition
+  // e.g. (x*-4) that needs whitespace.
+  if (diagnoseRangeOperatorMisspell(Context.Diags, UDRE) ||
+      diagnoseIncDecOperator(Context.Diags, UDRE) ||
+      diagnoseOperatorJuxtaposition(UDRE, DC) ||
+      diagnoseNonexistentPowerOperator(Context.Diags, UDRE, DC)) {
+    return errorResult();
+  }
+
+  // TODO: Name will be a compound name if it was written explicitly as
+  // one, but we should also try to propagate labels into this.
+  DeclNameLoc nameLoc = UDRE->getNameLoc();
+
+  Identifier simpleName = Name.getBaseIdentifier();
+  const char *buffer = simpleName.get();
+  llvm::SmallString<64> expectedIdentifier;
+  bool isConfused = false;
+  uint32_t codepoint;
+  uint32_t firstConfusableCodepoint = 0;
+  int totalCodepoints = 0;
+  int offset = 0;
+  while ((codepoint = validateUTF8CharacterAndAdvance(
+              buffer, buffer + strlen(buffer))) != ~0U) {
+    int length = (buffer - simpleName.get()) - offset;
+    if (auto expectedCodepoint =
+            confusable::tryConvertConfusableCharacterToASCII(codepoint)) {
+      if (firstConfusableCodepoint == 0) {
+        firstConfusableCodepoint = codepoint;
+      }
+      isConfused = true;
+      expectedIdentifier += expectedCodepoint;
+    } else {
+      expectedIdentifier += (char)codepoint;
+    }
+
+    totalCodepoints++;
+
+    offset += length;
+  }
+
+  auto emitBasicError = [&] {
+    if (Name.isSimpleName(Context.Id_self)) {
+      // `self` gets diagnosed with a different error when it can't be found.
+      Context.Diags.diagnose(Loc, diag::cannot_find_self_in_scope)
+          .highlight(UDRE->getSourceRange());
+    } else {
+      Context.Diags
+          .diagnose(Loc, diag::cannot_find_in_scope, Name, Name.isOperator())
+          .highlight(UDRE->getSourceRange());
+    }
+
+    if (!Context.LangOpts.DisableExperimentalClangImporterDiagnostics) {
+      Context.getClangModuleLoader()->diagnoseTopLevelValue(Name.getFullName());
+    }
+  };
+
+  if (!isConfused) {
+    if (Name.isSimpleName(Context.Id_Self)) {
+      if (DeclContext *typeContext = DC->getInnermostTypeContext()) {
+        Type SelfType = typeContext->getSelfInterfaceType();
+
+        if (typeContext->getSelfClassDecl() &&
+            !typeContext->getSelfClassDecl()->isForeignReferenceType())
+          SelfType = DynamicSelfType::get(SelfType, Context);
+        return new (Context)
+            TypeExpr(new (Context) SelfTypeRepr(SelfType, Loc));
+      }
+    }
+
+    TypoCorrectionResults corrections(Name, nameLoc);
+
+    // FIXME: Don't perform typo correction inside macro arguments, because it
+    // will invoke synthesizing declarations in this scope, which will attempt
+    // to expand this macro which leads to circular reference errors.
+    if (!namelookup::isInMacroArgument(DC->getParentSourceFile(),
+                                       UDRE->getLoc())) {
+      TypeChecker::performTypoCorrection(DC, UDRE->getRefKind(), Type(),
+                                         lookupOptions, corrections);
+    }
+
+    if (auto typo = corrections.claimUniqueCorrection()) {
+      auto diag = Context.Diags.diagnose(
+          Loc, diag::cannot_find_in_scope_corrected, Name, Name.isOperator(),
+          typo->CorrectedName.getBaseIdentifier().str());
+      diag.highlight(UDRE->getSourceRange());
+      typo->addFixits(diag);
+    } else {
+      emitBasicError();
+    }
+
+    corrections.noteAllCandidates();
+  } else {
+    emitBasicError();
+
+    if (totalCodepoints == 1) {
+      auto charNames = confusable::getConfusableAndBaseCodepointNames(
+          firstConfusableCodepoint);
+      Context.Diags
+          .diagnose(Loc, diag::single_confusable_character,
+                    UDRE->getName().isOperator(), simpleName.str(),
+                    charNames.first, expectedIdentifier, charNames.second)
+          .fixItReplace(Loc, expectedIdentifier);
+    } else {
+      Context.Diags
+          .diagnose(Loc, diag::confusable_character,
+                    UDRE->getName().isOperator(), simpleName.str(),
+                    expectedIdentifier)
+          .fixItReplace(Loc, expectedIdentifier);
+    }
+  }
+
+  // TODO: consider recovering from here.  We may want some way to suppress
+  // downstream diagnostics, though.
+  return errorResult();
+}
+
 /// If an expression references 'self.init' or 'super.init' in an
 /// initializer context, returns the implicit 'self' decl of the constructor.
 /// Otherwise, return nil.
@@ -1162,6 +1191,11 @@ class PreCheckTarget final : public ASTWalker {
   /// For the given statement, mark any valid SingleValueStmtExpr children.
   void markAnyValidSingleValueStmts(Stmt *S);
 
+  /// For the given single value expr that's a `for`-expression, run the
+  /// desugaring transformation. For all other kinds of single value statement
+  /// expressions do nothing.
+  void transformForExpression(SingleValueStmtExpr *E);
+
   PreCheckTarget(DeclContext *dc) : Ctx(dc->getASTContext()), DC(dc) {}
 
 public:
@@ -1253,7 +1287,8 @@ class PreCheckTarget final : public ASTWalker {
         }
 
         if (isa<UnresolvedDotExpr>(parentExpr) ||
-            isa<MemberRefExpr>(parentExpr)) {
+            isa<MemberRefExpr>(parentExpr) ||
+            isa<ErrorExpr>(parentExpr)) {
           return true;
         } else if (auto *SE = dyn_cast<SubscriptExpr>(parentExpr)) {
           // 'super[]' is valid, but 'x[super]' is not.
@@ -1316,8 +1351,9 @@ class PreCheckTarget final : public ASTWalker {
           lastInnerParenLoc = PE->getLParenLoc();
           parent = nextParent;
         }
-
-        if (isa<ApplyExpr>(parent) || isa<UnresolvedMemberExpr>(parent)) {
+        
+        if (isa<ApplyExpr>(parent) || isa<UnresolvedMemberExpr>(parent) ||
+            isa<MacroExpansionExpr>(parent)) {
           // If outermost paren is associated with a call or
           // a member reference, it might be valid to have `&`
           // before all of the parens.
@@ -1338,6 +1374,11 @@ class PreCheckTarget final : public ASTWalker {
           return finish(false, nullptr);
         }
       }
+      if (auto *accessor = DC->getInnermostPropertyAccessorContext()) {
+        if (accessor->isMutateAccessor()) {
+          return finish(true, expr);
+        }
+      }
 
       diags.diagnose(expr->getStartLoc(), diag::extraneous_address_of);
       return finish(false, nullptr);
@@ -1351,8 +1392,10 @@ class PreCheckTarget final : public ASTWalker {
     if (auto *assignment = dyn_cast<AssignExpr>(expr))
       markAcceptableDiscardExprs(assignment->getDest());
 
-    if (auto *SVE = dyn_cast<SingleValueStmtExpr>(expr))
+    if (auto *SVE = dyn_cast<SingleValueStmtExpr>(expr)) {
       checkSingleValueStmtExpr(SVE);
+      transformForExpression(SVE);
+    }
 
     return finish(true, expr);
   }
@@ -1665,6 +1708,59 @@ void PreCheckTarget::checkSingleValueStmtExpr(SingleValueStmtExpr *SVE) {
   }
 }
 
+void PreCheckTarget::transformForExpression(SingleValueStmtExpr *SVE) {
+  if (SVE->getStmtKind() != SingleValueStmtExpr::Kind::For) {
+    return;
+  }
+
+  auto *declCtx = SVE->getDeclContext();
+  auto &astCtx = declCtx->getASTContext();
+
+  auto sveLoc = SVE->getLoc();
+
+  auto *varDecl = new (astCtx)
+      VarDecl(false, VarDecl::Introducer::Var, sveLoc,
+              astCtx.getIdentifier("$forExpressionResult"), declCtx);
+
+  auto namedPattern = NamedPattern::createImplicit(astCtx, varDecl);
+
+  auto *initFunc = new (astCtx) UnresolvedMemberExpr(
+      sveLoc, DeclNameLoc(), DeclNameRef(DeclBaseName::createConstructor()),
+      true);
+  auto *callExpr = CallExpr::createImplicitEmpty(astCtx, initFunc);
+  auto *initExpr =
+      new (astCtx) UnresolvedMemberChainResultExpr(callExpr, initFunc);
+
+  auto *bindingDecl = PatternBindingDecl::createImplicit(
+      astCtx, StaticSpellingKind::None, namedPattern, initExpr, declCtx);
+
+  SVE->setForExpressionPreamble({varDecl, bindingDecl});
+
+  // For-expressions always have a single branch.
+  SmallVector<Stmt *, 1> scratch;
+  for (auto *branch : SVE->getBranches(scratch)) {
+    auto *BS = dyn_cast<BraceStmt>(branch);
+    if (!BS)
+      continue;
+
+    auto &result = BS->getElements().back();
+    if (auto stmt = result.dyn_cast<Stmt *>()) {
+      if (auto *then = dyn_cast<ThenStmt>(stmt)) {
+        auto *declRefExpr =
+            new (astCtx) DeclRefExpr(varDecl, DeclNameLoc(), true);
+        auto *dotExpr = new (astCtx) UnresolvedDotExpr(
+            declRefExpr, SourceLoc(),
+            DeclNameRef(DeclBaseName(astCtx.Id_append)), DeclNameLoc(), true);
+        auto *argumentList = ArgumentList::createImplicit(
+            astCtx, {Argument::unlabeled(then->getResult())});
+        auto *callExpr =
+            CallExpr::createImplicit(astCtx, dotExpr, argumentList);
+        then->setResult(callExpr);
+      }
+    }
+  }
+}
+
 void PreCheckTarget::markAnyValidSingleValueStmts(Expr *E) {
   auto findAssignment = [&]() -> AssignExpr * {
     // Don't consider assignments if we have a parent expression (as otherwise
@@ -1853,7 +1949,7 @@ TypeExpr *PreCheckTarget::simplifyUnresolvedSpecializeExpr(
     UnresolvedSpecializeExpr *us) {
   // If this is a reference type a specialized type, form a TypeExpr.
   // The base should be a TypeExpr that we already resolved.
-  if (auto *te = dyn_cast<TypeExpr>(us->getSubExpr())) {
+  if (auto *te = dyn_cast_or_null<TypeExpr>(us->getSubExpr())) {
     if (auto *declRefTR =
             dyn_cast_or_null<DeclRefTypeRepr>(te->getTypeRepr())) {
       return TypeExpr::createForSpecializedDecl(
@@ -2346,14 +2442,17 @@ TypeExpr *PreCheckTarget::simplifyTypeExpr(Expr *E) {
       return nullptr;
     };
 
+    auto makeErrorTypeRepr = [&](Expr *E) -> ErrorTypeRepr * {
+      return ErrorTypeRepr::create(Ctx, E->getSourceRange(), E);
+    };
+
     TupleTypeRepr *ArgsTypeRepr = extractInputTypeRepr(AE->getArgsExpr());
     if (!ArgsTypeRepr) {
       Ctx.Diags.diagnose(AE->getArgsExpr()->getLoc(),
                          diag::expected_type_before_arrow);
-      auto ArgRange = AE->getArgsExpr()->getSourceRange();
-      auto ErrRepr = ErrorTypeRepr::create(Ctx, ArgRange);
+      auto ErrRepr = makeErrorTypeRepr(AE->getArgsExpr());
       ArgsTypeRepr =
-          TupleTypeRepr::create(Ctx, {ErrRepr}, ArgRange);
+          TupleTypeRepr::create(Ctx, {ErrRepr}, ErrRepr->getSourceRange());
     }
 
     TypeRepr *ThrownTypeRepr = nullptr;
@@ -2366,8 +2465,7 @@ TypeExpr *PreCheckTarget::simplifyTypeExpr(Expr *E) {
     if (!ResultTypeRepr) {
       Ctx.Diags.diagnose(AE->getResultExpr()->getLoc(),
                          diag::expected_type_after_arrow);
-      ResultTypeRepr =
-          ErrorTypeRepr::create(Ctx, AE->getResultExpr()->getSourceRange());
+      ResultTypeRepr = makeErrorTypeRepr(AE->getResultExpr());
     }
 
     auto NewTypeRepr = new (Ctx)
@@ -2532,11 +2630,11 @@ void PreCheckTarget::resolveKeyPathExpr(KeyPathExpr *KPE) {
         (void)outermostExpr;
         assert(OEE == outermostExpr);
         expr = OEE->getSubExpr();
-      } else if (auto AE = dyn_cast<ApplyExpr>(expr)) {
+      } else if (auto CE = dyn_cast<CallExpr>(expr)) {
         // foo(), foo(val value: Int) or unapplied foo
         components.push_back(KeyPathExpr::Component::forUnresolvedApply(
-            getASTContext(), AE->getArgs()));
-        expr = AE->getFn();
+            getASTContext(), CE->getArgs()));
+        expr = CE->getFn();
       } else {
         if (emitErrors) {
           // \(<expr>) may be an attempt to write a string interpolation outside
diff --git a/lib/Sema/ResilienceDiagnostics.cpp b/lib/Sema/ResilienceDiagnostics.cpp
index fa6decc40b4d5..3a4dbd1112107 100644
--- a/lib/Sema/ResilienceDiagnostics.cpp
+++ b/lib/Sema/ResilienceDiagnostics.cpp
@@ -76,15 +76,7 @@ bool TypeChecker::diagnoseInlinableDeclRefAccess(SourceLoc loc,
   }
 
   // Remember that the module defining the decl must be imported publicly.
-  recordRequiredImportAccessLevelForDecl(
-      D, DC, AccessLevel::Public,
-      [&](AttributedImport<ImportedModule> attributedImport) {
-        ModuleDecl *importedVia = attributedImport.module.importedModule,
-                   *sourceModule = D->getModuleContext();
-        Context.Diags.diagnose(loc, diag::module_api_import, D, importedVia,
-                               sourceModule, importedVia == sourceModule,
-                               /*isImplicit*/ false);
-      });
+  recordRequiredImportAccessLevelForDecl(D, DC, AccessLevel::Public, loc);
 
   // General check on access-level of the decl.
   auto declAccessScope =
@@ -141,7 +133,9 @@ bool TypeChecker::diagnoseInlinableDeclRefAccess(SourceLoc loc,
     Context.Diags.diagnose(problematicImport->importLoc,
                            diag::decl_import_via_here, D,
                            problematicImport->accessLevel,
-                           problematicImport->module.importedModule);
+                           problematicImport->module.importedModule,
+                           problematicImport->module.importedModule
+                             ->isClangHeaderImportModule());
   }
 
   return (downgradeToWarning == DowngradeToWarning::No);
@@ -221,12 +215,50 @@ static bool diagnoseTypeAliasDeclRefExportability(SourceLoc loc,
     ctx.Diags.diagnose(limitImport->importLoc,
                        diag::decl_import_via_here, D,
                        limitImport->accessLevel,
-                       limitImport->module.importedModule);
+                       limitImport->module.importedModule,
+                       limitImport->module.importedModule
+                         ->isClangHeaderImportModule());
   }
 
   return true;
 }
 
+/// Returns true if access to \p D should be diagnosed during exportability
+/// checking. These diagnostics would typically be handled by the access
+/// checker, and therefore should be suppressed to avoid duplicate diagnostics.
+/// However, extensions are special because they do not have an intrinsic access
+/// level and therefore the access checker does not currently handle them.
+/// Instead, diagnostics for decls referenced in extension signatures are
+/// deferred to exportability checking. An exportable extension is effectively a
+/// public extension.
+static bool shouldDiagnoseDeclAccess(const ValueDecl *D,
+                                     const ExportContext &where) {
+  auto reason = where.getExportabilityReason();
+  auto DC = where.getDeclContext();
+  if (!reason)
+    return false;
+
+  switch (*reason) {
+  case ExportabilityReason::ExtensionWithPublicMembers:
+  case ExportabilityReason::ExtensionWithConditionalConformances:
+    return true;
+  case ExportabilityReason::Inheritance:
+    return isa<ProtocolDecl>(D);
+  case ExportabilityReason::AvailableAttribute:
+    // If the context is an extension and that extension has an explicit
+    // access level then availability domains access has already been
+    // diagnosed.
+    if (auto *ED = dyn_cast_or_null<ExtensionDecl>(DC->getAsDecl()))
+      return !ED->getAttrs().getAttribute<AccessControlAttr>();
+    return false;
+
+  case ExportabilityReason::General:
+  case ExportabilityReason::ResultBuilder:
+  case ExportabilityReason::PropertyWrapper:
+    return false;
+  }
+}
+
 static bool diagnoseValueDeclRefExportability(SourceLoc loc, const ValueDecl *D,
                                               const ExportContext &where) {
   assert(where.mustOnlyReferenceExportedDecls());
@@ -245,7 +277,8 @@ static bool diagnoseValueDeclRefExportability(SourceLoc loc, const ValueDecl *D,
       D, DC, AccessLevel::Public,
       [&](AttributedImport<ImportedModule> attributedImport) {
         if (where.isExported() && reason != ExportabilityReason::General &&
-            originKind != DisallowedOriginKind::NonPublicImport) {
+            originKind != DisallowedOriginKind::NonPublicImport &&
+            originKind != DisallowedOriginKind::InternalBridgingHeaderImport) {
           // These may be reported twice, for the Type and for the TypeRepr.
           ModuleDecl *importedVia = attributedImport.module.importedModule,
                      *sourceModule = D->getModuleContext();
@@ -255,32 +288,45 @@ static bool diagnoseValueDeclRefExportability(SourceLoc loc, const ValueDecl *D,
         }
       });
 
-  // Access levels from imports are reported with the others access levels.
-  // Except for extensions and protocol conformances, we report them here.
-  if (originKind == DisallowedOriginKind::NonPublicImport) {
-    bool reportHere = [&] {
-      switch (*reason) {
-        case ExportabilityReason::ExtensionWithPublicMembers:
-        case ExportabilityReason::ExtensionWithConditionalConformances:
-          return true;
-        case ExportabilityReason::Inheritance:
-          return isa<ProtocolDecl>(D);
-        default:
-          return false;
-      }
-    }();
-    if (!reportHere)
-      return false;
-  }
-
-  if (originKind == DisallowedOriginKind::None)
+  switch (originKind) {
+  case DisallowedOriginKind::None:
+    // The decl does not come from a source that needs to be checked for
+    // exportability.
     return false;
 
-  // Some diagnostics emitted with the `MemberImportVisibility` feature enabled
-  // subsume these diagnostics.
-  if (originKind == DisallowedOriginKind::MissingImport &&
-      ctx.LangOpts.hasFeature(Feature::MemberImportVisibility) && SF)
-    return false;
+  case DisallowedOriginKind::NonPublicImport:
+  case DisallowedOriginKind::InternalBridgingHeaderImport:
+    // With a few exceptions, access levels from imports are diagnosed during
+    // access checking and should be skipped here.
+    if (!shouldDiagnoseDeclAccess(D, where))
+      return false;
+    break;
+
+  case DisallowedOriginKind::MissingImport:
+    // Some diagnostics emitted with the `MemberImportVisibility` feature
+    // enabled subsume these diagnostics.
+    if (ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                                /*allowMigration=*/true) &&
+        SF)
+      return false;
+    break;
+
+  case DisallowedOriginKind::SPIOnly:
+    // Availability attributes referring to availability domains from modules
+    // that are imported @_spiOnly in a -library-level=api will not be printed
+    // in the public swiftinterface of the module and should therefore not be
+    // diagnosed for exportability.
+    if (reason && reason == ExportabilityReason::AvailableAttribute &&
+        ctx.LangOpts.LibraryLevel == LibraryLevel::API)
+      return false;
+    break;
+
+  case DisallowedOriginKind::ImplementationOnly:
+  case DisallowedOriginKind::SPIImported:
+  case DisallowedOriginKind::SPILocal:
+  case DisallowedOriginKind::FragileCxxAPI:
+    break;
+  }
 
   if (auto accessor = dyn_cast<AccessorDecl>(D)) {
     // Only diagnose accessors if their disallowed origin kind differs from
@@ -328,7 +374,9 @@ static bool diagnoseValueDeclRefExportability(SourceLoc loc, const ValueDecl *D,
     ctx.Diags.diagnose(import->importLoc,
                        diag::decl_import_via_here, D,
                        import->accessLevel,
-                       import->module.importedModule);
+                       import->module.importedModule,
+                       import->module.importedModule
+                         ->isClangHeaderImportModule());
   }
 
   return true;
@@ -414,7 +462,9 @@ TypeChecker::diagnoseConformanceExportability(SourceLoc loc,
     ctx.Diags.diagnose(limitImport->importLoc,
                        diag::decl_import_via_here, ext,
                        limitImport->accessLevel,
-                       limitImport->module.importedModule);
+                       limitImport->module.importedModule,
+                       limitImport->module.importedModule
+                         ->isClangHeaderImportModule());
   }
 
   return true;
diff --git a/lib/Sema/SourceLoader.cpp b/lib/Sema/SourceLoader.cpp
index 15602b6bb2132..b146d8cacddd6 100644
--- a/lib/Sema/SourceLoader.cpp
+++ b/lib/Sema/SourceLoader.cpp
@@ -139,29 +139,23 @@ ModuleDecl *SourceLoader::loadModule(SourceLoc importLoc,
     addFile(new (Ctx) SourceFile(*importMod, SourceFileKind::Library, bufferID,
                                  opts));
   });
-  if (EnableLibraryEvolution)
+  if (Ctx.LangOpts.hasFeature(Feature::LibraryEvolution))
     importMod->setResilienceStrategy(ResilienceStrategy::Resilient);
   Ctx.addLoadedModule(importMod);
+  Ctx.bumpGeneration();
+  ModulesToBindExtensions.push_back(importMod);
 
   performImportResolution(importMod);
-  bindExtensions(*importMod);
   return importMod;
 }
 
 void SourceLoader::loadExtensions(NominalTypeDecl *nominal,
                                   unsigned previousGeneration) {
-  // Type-checking the source automatically loads all extensions; there's
-  // nothing to do here.
-}
-
-ModuleDependencyVector
-SourceLoader::getModuleDependencies(Identifier moduleName,
-                                    StringRef moduleOutputPath, StringRef sdkModuleOutputPath,
-                                    const llvm::DenseSet<clang::tooling::dependencies::ModuleID> &alreadySeenClangModules,
-                                    clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-                                    InterfaceSubContextDelegate &delegate,
-                                    llvm::PrefixMapper* mapper,
-                                    bool isTestableImport) {
-  // FIXME: Implement?
-  return {};
+  // Given we do full extension binding per module, there's no benefit to
+  // tracking generations, we just bind extensions for any modules we haven't
+  // yet bound. We take the vector before iterating to avoid reentrancy.
+  std::vector<ModuleDecl *> modulesToBind;
+  std::swap(ModulesToBindExtensions, modulesToBind);
+  for (auto *M : modulesToBind)
+    bindExtensions(*M);
 }
diff --git a/lib/Sema/SyntacticElementTarget.cpp b/lib/Sema/SyntacticElementTarget.cpp
index e2236f4308a6a..6aa7a9e33cdcd 100644
--- a/lib/Sema/SyntacticElementTarget.cpp
+++ b/lib/Sema/SyntacticElementTarget.cpp
@@ -36,17 +36,6 @@ SyntacticElementTarget::SyntacticElementTarget(
   assert((!contextualInfo.getType() || contextualPurpose != CTP_Unused) &&
          "Purpose for conversion type was not specified");
 
-  // Take a look at the conversion type to check to make sure it is sensible.
-  if (auto type = contextualInfo.getType()) {
-    // If we're asked to convert to an UnresolvedType, then ignore the request.
-    // This happens when CSDiags nukes a type.
-    if (type->is<UnresolvedType>() ||
-        (type->is<MetatypeType>() && type->hasUnresolvedType())) {
-      contextualInfo.typeLoc = TypeLoc();
-      contextualPurpose = CTP_Unused;
-    }
-  }
-
   kind = Kind::expression;
   expression.expression = expr;
   expression.dc = dc;
@@ -141,7 +130,7 @@ SyntacticElementTarget::forInitialization(Expr *initializer, DeclContext *dc,
   // Determine the contextual type for the initialization.
   TypeLoc contextualType;
   if (!(isa<OptionalSomePattern>(pattern) && !pattern->isImplicit()) &&
-      patternType && !patternType->is<UnresolvedType>()) {
+      patternType && !patternType->is<PlaceholderType>()) {
     contextualType = TypeLoc::withoutLoc(patternType);
 
     // Only provide a TypeLoc if it makes sense to allow diagnostics.
@@ -181,13 +170,14 @@ SyntacticElementTarget SyntacticElementTarget::forInitialization(
   return result;
 }
 
-SyntacticElementTarget
-SyntacticElementTarget::forReturn(ReturnStmt *returnStmt, Type contextTy,
-                                  DeclContext *dc) {
+SyntacticElementTarget SyntacticElementTarget::forReturn(ReturnStmt *returnStmt,
+                                                         Expr *returnExpr,
+                                                         Type contextTy,
+                                                         DeclContext *dc) {
   assert(contextTy);
   assert(returnStmt->hasResult() && "Must have result to be type-checked");
   ContextualTypeInfo contextInfo(contextTy, CTP_ReturnStmt);
-  SyntacticElementTarget target(returnStmt->getResult(), dc, contextInfo,
+  SyntacticElementTarget target(returnExpr, dc, contextInfo,
                                 /*isDiscarded*/ false);
   target.expression.parentReturnStmt = returnStmt;
   return target;
@@ -261,7 +251,6 @@ bool SyntacticElementTarget::contextualTypeIsOnlyAHint() const {
   switch (getExprContextualTypePurpose()) {
   case CTP_Initialization:
     return !infersOpaqueReturnType() && !isOptionalSomePatternInit();
-  case CTP_ForEachStmt:
   case CTP_ForEachSequence:
     return true;
   case CTP_Unused:
@@ -302,12 +291,21 @@ void SyntacticElementTarget::markInvalid() const {
     InvalidationWalker(ASTContext &ctx) : Ctx(ctx) {}
 
     PreWalkResult<Expr *> walkToExprPre(Expr *E) override {
-      if (!E->getType())
-        E->setType(ErrorType::get(Ctx));
-
+      E->setType(ErrorType::get(Ctx));
       return Action::Continue(E);
     }
 
+    PreWalkResult<Pattern *> walkToPatternPre(Pattern *P) override {
+      P->setType(ErrorType::get(Ctx));
+
+      // For a named pattern, set it on the variable. This stops us from
+      // attempting to double-type-check variables we've already type-checked.
+      if (auto *NP = dyn_cast<NamedPattern>(P))
+        NP->getDecl()->setNamingPattern(NP);
+
+      return Action::Continue(P);
+    }
+
     PreWalkAction walkToDeclPre(Decl *D) override {
       // Mark any VarDecls and PatternBindingDecls as invalid.
       if (auto *VD = dyn_cast<VarDecl>(D)) {
diff --git a/lib/Sema/TypeCheckAccess.cpp b/lib/Sema/TypeCheckAccess.cpp
index c5c0987b90bdc..fe19abefed39f 100644
--- a/lib/Sema/TypeCheckAccess.cpp
+++ b/lib/Sema/TypeCheckAccess.cpp
@@ -28,10 +28,12 @@
 #include "swift/AST/Import.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/Pattern.h"
+#include "swift/AST/PrettyStackTrace.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/Basic/Assertions.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
+#include "clang/AST/Type.h"
 
 using namespace swift;
 
@@ -70,10 +72,22 @@ static void forAllRequirementTypes(
 using CheckTypeAccessCallback =
     void(AccessScope, const TypeRepr *, DowngradeToWarning, ImportAccessLevel);
 
+using CheckDeclAccessCallback = void(AccessScope, SourceLoc, ImportAccessLevel);
+
 class AccessControlCheckerBase {
 protected:
   bool checkUsableFromInline;
 
+  bool shouldSkipChecking(const ValueDecl *decl);
+
+  /// Returns true if access checking ought to be skipped for the given
+  /// `AccessScope`.
+  bool shouldSkipAccessCheckingInContext(AccessScope contextAccessScope,
+                                         const ASTContext &ctx);
+
+  ImportAccessLevel getImportAccessForDecl(const ValueDecl *decl,
+                                           const DeclContext *useDC);
+
   void checkTypeAccessImpl(
       Type type, TypeRepr *typeRepr, AccessScope contextAccessScope,
       const DeclContext *useDC, bool mayBeInferred,
@@ -102,6 +116,12 @@ class AccessControlCheckerBase {
     });
   }
 
+  void checkAvailabilityDomains(const Decl *D);
+
+  void checkDeclAccess(SourceLoc loc, const ValueDecl *decl,
+                       AccessScope contextAccessScope, const DeclContext *useDC,
+                       llvm::function_ref<CheckDeclAccessCallback> diagnose);
+
   AccessControlCheckerBase(bool checkUsableFromInline)
       : checkUsableFromInline(checkUsableFromInline) {}
 
@@ -117,10 +137,50 @@ class AccessControlCheckerBase {
     const ValueDecl *ownerDecl);
 
   void checkGlobalActorAccess(const Decl *D);
+
+  void checkAvailabilityDomains(const Decl *D, AccessScope accessScope,
+                                AccessLevel contextAccess);
 };
 
 } // end anonymous namespace
 
+bool AccessControlCheckerBase::shouldSkipChecking(const ValueDecl *decl) {
+  if (!checkUsableFromInline)
+    return false;
+
+  if (decl->getFormalAccess() != AccessLevel::Internal &&
+      decl->getFormalAccess() != AccessLevel::Package)
+    return true;
+  return !decl->isUsableFromInline();
+}
+
+bool AccessControlCheckerBase::shouldSkipAccessCheckingInContext(
+    AccessScope contextAccessScope, const ASTContext &ctx) {
+  if (ctx.isAccessControlDisabled())
+    return true;
+
+  // Don't spend time checking local declarations; this is always valid by the
+  // time we get to this point.
+  if (contextAccessScope.isInContext() &&
+      contextAccessScope.getDeclContext()->isLocalContext())
+    return true;
+
+  return false;
+}
+
+ImportAccessLevel
+AccessControlCheckerBase::getImportAccessForDecl(const ValueDecl *decl,
+                                                 const DeclContext *useDC) {
+  auto complainImport = decl->getImportAccessFrom(useDC);
+
+  // Don't complain about an import that doesn't restrict the access
+  // level of the decl. This can happen with imported `package` decls.
+  if (complainImport && complainImport->accessLevel >= decl->getFormalAccess())
+    return std::nullopt;
+
+  return complainImport;
+}
+
 /// Searches the given type representation for a `DeclRefTypeRepr` that is
 /// bound to a type declaration with the given access scope. The type
 /// representation is searched in source order. For example, nodes in
@@ -201,30 +261,15 @@ void AccessControlCheckerBase::checkTypeAccessImpl(
     llvm::function_ref<CheckTypeAccessCallback> diagnose) {
 
   auto &Context = useDC->getASTContext();
-  if (Context.isAccessControlDisabled())
-    return;
-  // Don't spend time checking local declarations; this is always valid by the
-  // time we get to this point.
-  if (contextAccessScope.isInContext() &&
-      contextAccessScope.getDeclContext()->isLocalContext())
+  if (shouldSkipAccessCheckingInContext(contextAccessScope, Context))
     return;
 
   // Report where it was imported from.
   if (contextAccessScope.isPublicOrPackage()) {
     auto report = [&](const DeclRefTypeRepr *typeRepr, const ValueDecl *VD) {
-      // Remember that the module defining the decl must be imported publicly.
+      SourceLoc diagLoc = typeRepr ? typeRepr->getLoc() : SourceLoc();
       recordRequiredImportAccessLevelForDecl(
-          VD, useDC, contextAccessScope.accessLevelForDiagnostics(),
-          [&](AttributedImport<ImportedModule> attributedImport) {
-            SourceLoc diagLoc =
-                typeRepr ? typeRepr->getLoc() : extractNearestSourceLoc(useDC);
-            ModuleDecl *importedVia = attributedImport.module.importedModule,
-                       *sourceModule = VD->getModuleContext();
-            Context.Diags.diagnose(diagLoc, diag::module_api_import, VD,
-                                   importedVia, sourceModule,
-                                   importedVia == sourceModule,
-                                   /*isImplicit*/ !typeRepr);
-          });
+          VD, useDC, contextAccessScope.accessLevelForDiagnostics(), diagLoc);
     };
 
     if (typeRepr) {
@@ -239,7 +284,7 @@ void AccessControlCheckerBase::checkTypeAccessImpl(
         return TypeWalker::Action::Continue;
       }));
     }
-  };
+  }
 
   AccessScope problematicAccessScope = AccessScope::getPublic();
 
@@ -317,19 +362,36 @@ void AccessControlCheckerBase::checkTypeAccessImpl(
     const ValueDecl *VD = complainRepr->getBoundDecl();
     assert(VD &&
            "findTypeDeclWithAccessScope should return bound TypeReprs only");
-    complainImport = VD->getImportAccessFrom(useDC);
-
-    // Don't complain about an import that doesn't restrict the access
-    // level of the decl. This can happen with imported `package` decls.
-    if (complainImport.has_value() &&
-        complainImport->accessLevel >= VD->getFormalAccess())
-      complainImport = std::nullopt;
+    complainImport = getImportAccessForDecl(VD, useDC);
   }
 
   diagnose(problematicAccessScope, complainRepr, downgradeToWarning,
            complainImport);
 }
 
+void AccessControlCheckerBase::checkDeclAccess(
+    SourceLoc loc, const ValueDecl *decl, AccessScope contextAccessScope,
+    const DeclContext *useDC,
+    llvm::function_ref<CheckDeclAccessCallback> diagnose) {
+
+  auto &ctx = useDC->getASTContext();
+  if (shouldSkipAccessCheckingInContext(contextAccessScope, ctx))
+    return;
+
+  recordRequiredImportAccessLevelForDecl(
+      decl, useDC, contextAccessScope.accessLevelForDiagnostics(), loc);
+
+  AccessScope declAccessScope =
+      decl->getFormalAccessScope(useDC, checkUsableFromInline);
+  if (contextAccessScope.hasEqualDeclContextWith(declAccessScope) ||
+      contextAccessScope.isChildOf(declAccessScope))
+    return;
+
+  // The reference to the decl violates the rules of access control.
+  ImportAccessLevel complainImport = getImportAccessForDecl(decl, useDC);
+  diagnose(declAccessScope, loc, complainImport);
+}
+
 /// Checks if the access scope of the type described by \p TL is valid for the
 /// type to be the type of \p context. If it isn't, calls \p diagnose with a
 /// TypeRepr representing the offending part of \p TL.
@@ -363,12 +425,10 @@ void AccessControlCheckerBase::checkTypeAccess(
 static void highlightOffendingType(InFlightDiagnostic &diag,
                                    const TypeRepr *complainRepr) {
   if (!complainRepr) {
-    diag.flush();
     return;
   }
 
   diag.highlight(complainRepr->getSourceRange());
-  diag.flush();
 
   if (auto *declRefTR = dyn_cast<DeclRefTypeRepr>(complainRepr)) {
     const ValueDecl *VD = declRefTR->getBoundDecl();
@@ -394,12 +454,16 @@ static void noteLimitingImport(const Decl *userDecl, ASTContext &ctx,
     if (userDecl)
       userDecl->diagnose(diag::decl_import_via_local, complainDecl,
                          limitImport->accessLevel,
-                         limitImport->module.importedModule);
+                         limitImport->module.importedModule,
+                         limitImport->module.importedModule
+                           ->isClangHeaderImportModule());
 
     if (limitImport->importLoc.isValid())
       ctx.Diags.diagnose(limitImport->importLoc, diag::decl_import_via_here,
                          complainDecl, limitImport->accessLevel,
-                         limitImport->module.importedModule);
+                         limitImport->module.importedModule,
+                         limitImport->module.importedModule
+                           ->isClangHeaderImportModule());
   } else if (limitImport->importLoc.isValid()) {
     ctx.Diags.diagnose(limitImport->importLoc, diag::module_imported_here,
                        limitImport->module.importedModule,
@@ -499,7 +563,7 @@ void AccessControlCheckerBase::checkGenericParamAccess(
     if (downgradeToWarning == DowngradeToWarning::Yes)
       diagID = diag::generic_param_usable_from_inline_warn;
     auto diag =
-        Context.Diags.diagnose(ownerDecl, diagID, ownerDecl->getDescriptiveKind(),
+        Context.Diags.diagnose(ownerDecl, diagID, ownerDecl,
                                accessControlErrorKind == ACEK::Requirement);
     highlightOffendingType(diag, complainRepr);
     noteLimitingImport(/*userDecl*/nullptr, Context, minImportLimit, complainRepr);
@@ -515,9 +579,8 @@ void AccessControlCheckerBase::checkGenericParamAccess(
   if (downgradeToWarning == DowngradeToWarning::Yes)
     diagID = diag::generic_param_access_warn;
   auto diag = Context.Diags.diagnose(
-      ownerDecl, diagID, ownerDecl->getDescriptiveKind(), isExplicit,
-      contextAccess, minAccess, isa<FileUnit>(DC),
-      accessControlErrorKind == ACEK::Requirement);
+      ownerDecl, diagID, ownerDecl, isExplicit, contextAccess, minAccess,
+      isa<FileUnit>(DC), accessControlErrorKind == ACEK::Requirement);
   highlightOffendingType(diag, complainRepr);
   noteLimitingImport(/*userDecl*/nullptr, Context, minImportLimit, complainRepr);
 }
@@ -567,6 +630,50 @@ void AccessControlCheckerBase::checkGlobalActorAccess(const Decl *D) {
       });
 }
 
+void AccessControlCheckerBase::checkAvailabilityDomains(
+    const Decl *D, AccessScope accessScope, AccessLevel contextAccess) {
+  auto &ctx = D->getASTContext();
+  for (auto attr : D->getSemanticAvailableAttrs()) {
+    if (auto *domainDecl = attr.getDomain().getDecl()) {
+      checkDeclAccess(
+          attr.getParsedAttr()->getDomainLoc(), domainDecl, accessScope,
+          D->getDeclContext(),
+          [&](AccessScope domainAccessScope, SourceLoc useLoc,
+              ImportAccessLevel importLimit) {
+            // FIXME: [availability] Improve diagnostics by indicating the decl
+            // that the formal access is implied by. Enum cases, associated
+            // types, protocol requirements, etc. inherit their access level
+            // from their context.
+
+            if (checkUsableFromInline) {
+              ctx.Diags.diagnose(
+                  useLoc, diag::attr_availability_domain_not_usable_from_inline,
+                  attr.getDomain(), attr.getParsedAttr(), D);
+              noteLimitingImport(nullptr, ctx, importLimit, domainDecl);
+              return;
+            }
+
+            ctx.Diags.diagnose(useLoc, diag::attr_availability_domain_access,
+                               attr.getDomain(),
+                               domainAccessScope.accessLevelForDiagnostics(),
+                               attr.getParsedAttr(), contextAccess, D);
+            noteLimitingImport(nullptr, ctx, importLimit, domainDecl);
+          });
+    }
+  }
+}
+
+void AccessControlCheckerBase::checkAvailabilityDomains(const Decl *D) {
+  auto VD = dyn_cast<ValueDecl>(D->getAbstractSyntaxDeclForAttributes());
+  if (!VD || shouldSkipChecking(VD))
+    return;
+
+  AccessScope contextAccessScope =
+      VD->getFormalAccessScope(VD->getDeclContext(), checkUsableFromInline);
+
+  checkAvailabilityDomains(VD, contextAccessScope, VD->getFormalAccess());
+}
+
 namespace {
 class AccessControlChecker : public AccessControlCheckerBase,
                              public DeclVisitor<AccessControlChecker> {
@@ -584,7 +691,7 @@ class AccessControlChecker : public AccessControlCheckerBase,
 
     DeclVisitor<AccessControlChecker>::visit(D);
     checkGlobalActorAccess(D);
-    checkAttachedMacrosAccess(D);
+    checkAvailabilityDomains(D);
   }
 
   // Force all kinds to be handled at a lower level.
@@ -601,6 +708,7 @@ class AccessControlChecker : public AccessControlCheckerBase,
   UNREACHABLE(Operator, "cannot appear in a type context")
   UNREACHABLE(PrecedenceGroup, "cannot appear in a type context")
   UNREACHABLE(Module, "cannot appear in a type context")
+  UNREACHABLE(Using, "cannot appear in a type context")
 
   UNREACHABLE(Param, "does not have access control")
   UNREACHABLE(GenericTypeParam, "does not have access control")
@@ -1324,19 +1432,6 @@ class AccessControlChecker : public AccessControlCheckerBase,
       noteLimitingImport(MD, minImportLimit, complainRepr);
     }
   }
-
-  void checkAttachedMacrosAccess(const Decl *D) {
-    for (auto customAttrC : D->getExpandedAttrs().getAttributes<CustomAttr>()) {
-      auto customAttr = const_cast<CustomAttr *>(customAttrC);
-      auto *macroDecl = D->getResolvedMacro(customAttr);
-      if (macroDecl) {
-        diagnoseDeclAvailability(
-            macroDecl, customAttr->getTypeRepr()->getSourceRange(), nullptr,
-            ExportContext::forDeclSignature(const_cast<Decl *>(D)),
-            std::nullopt);
-      }
-    }
-  }
 };
 
 class UsableFromInlineChecker : public AccessControlCheckerBase,
@@ -1345,13 +1440,6 @@ class UsableFromInlineChecker : public AccessControlCheckerBase,
   UsableFromInlineChecker()
       : AccessControlCheckerBase(/*checkUsableFromInline=*/true) {}
 
-  static bool shouldSkipChecking(const ValueDecl *VD) {
-    if (VD->getFormalAccess() != AccessLevel::Internal &&
-        VD->getFormalAccess() != AccessLevel::Package)
-      return true;
-    return !VD->isUsableFromInline();
-  };
-
   void visit(Decl *D) {
     if (!D->getASTContext().isSwiftVersionAtLeast(4, 2))
       return;
@@ -1365,6 +1453,7 @@ class UsableFromInlineChecker : public AccessControlCheckerBase,
 
     DeclVisitor<UsableFromInlineChecker>::visit(D);
     checkGlobalActorAccess(D);
+    checkAvailabilityDomains(D);
   }
 
   // Force all kinds to be handled at a lower level.
@@ -1381,6 +1470,7 @@ class UsableFromInlineChecker : public AccessControlCheckerBase,
   UNREACHABLE(Operator, "cannot appear in a type context")
   UNREACHABLE(PrecedenceGroup, "cannot appear in a type context")
   UNREACHABLE(Module, "cannot appear in a type context")
+  UNREACHABLE(Using, "cannot appear in a type context")
 
   UNREACHABLE(Param, "does not have access control")
   UNREACHABLE(GenericTypeParam, "does not have access control")
@@ -1388,6 +1478,7 @@ class UsableFromInlineChecker : public AccessControlCheckerBase,
   UNREACHABLE(MissingMember, "does not have access control")
   UNREACHABLE(MacroExpansion, "does not have access control")
   UNREACHABLE(BuiltinTuple, "BuiltinTupleDecl should not show up here")
+
 #undef UNREACHABLE
 
 #define UNINTERESTING(KIND) \
@@ -1859,6 +1950,15 @@ bool isFragileClangType(clang::QualType type) {
   // Builtin clang types are compatible with library evolution.
   if (underlyingTypePtr->isBuiltinType())
     return false;
+  if (const auto *ft = dyn_cast<clang::FunctionType>(underlyingTypePtr)) {
+    if (const auto *fpt =
+            dyn_cast<clang::FunctionProtoType>(underlyingTypePtr)) {
+      for (auto paramTy : fpt->getParamTypes())
+        if (isFragileClangType(paramTy))
+          return true;
+    }
+    return isFragileClangType(ft->getReturnType());
+  }
   // Pointers to non-fragile types are non-fragile.
   if (underlyingTypePtr->isPointerType())
     return isFragileClangType(underlyingTypePtr->getPointeeType());
@@ -2028,7 +2128,21 @@ swift::getDisallowedOriginKind(const Decl *decl,
           return DisallowedOriginKind::None;
         }
       }
+
+      // Allow SPI available use in an extension to an SPI available type.
+      // This is a narrow workaround for rdar://159292698 as this should be
+      // handled as part of the `where.isSPI()` above, but that context check
+      // is currently too permissive. It allows SPI use in SPI available which
+      // can break swiftinterfaces. The SPI availability logic likely need to be
+      // separated from normal SPI and treated more like availability.
+      auto ext = dyn_cast_or_null<ExtensionDecl>(where.getDeclContext());
+      if (ext) {
+        auto nominal = ext->getExtendedNominal();
+        if (nominal && nominal->isAvailableAsSPI())
+          return DisallowedOriginKind::None;
+      }
     }
+
     // SPI can only be exported in SPI.
     return where.getDeclContext()->getParentModule() == M ?
       DisallowedOriginKind::SPILocal :
@@ -2053,8 +2167,11 @@ swift::getDisallowedOriginKind(const Decl *decl,
   // See \c diagnoseValueDeclRefExportability.
   auto importSource = decl->getImportAccessFrom(where.getDeclContext());
   if (importSource.has_value() &&
-      importSource->accessLevel < AccessLevel::Public)
-    return DisallowedOriginKind::NonPublicImport;
+      importSource->accessLevel < AccessLevel::Public) {
+    return importSource->module.importedModule->isClangHeaderImportModule()
+      ? DisallowedOriginKind::InternalBridgingHeaderImport
+      : DisallowedOriginKind::NonPublicImport;
+  }
 
   return DisallowedOriginKind::None;
 }
@@ -2071,11 +2188,6 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
     // Don't bother checking errors.
     if (type && type->hasError())
       return;
-    
-    // If the decl which references this type is unavailable on the current
-    // platform, don't diagnose the availability of the type.
-    if (Where.getAvailability().isUnavailable())
-      return;
 
     diagnoseTypeAvailability(typeRepr, type, context->getLoc(),
                              Where.withReason(reason), flags);
@@ -2154,9 +2266,69 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
     checkType(customAttr->getType(), customAttr->getTypeRepr(), D);
   }
 
+  void checkAttachedMacros(const Decl *D) {
+    for (auto customAttrC : D->getExpandedAttrs().getAttributes<CustomAttr>()) {
+      auto customAttr = const_cast<CustomAttr *>(customAttrC);
+      auto *macroDecl = D->getResolvedMacro(customAttr);
+      if (macroDecl) {
+        diagnoseDeclAvailability(macroDecl,
+                                 customAttr->getTypeRepr()->getSourceRange(),
+                                 nullptr, Where, std::nullopt);
+      }
+    }
+  }
+
+  void checkAvailabilityDomains(const Decl *D) {
+    D = D->getAbstractSyntaxDeclForAttributes();
+
+    auto &ctx = D->getASTContext();
+    auto where = Where.withReason(ExportabilityReason::AvailableAttribute);
+    for (auto attr : D->getSemanticAvailableAttrs()) {
+      auto domain = attr.getDomain();
+      if (auto *domainDecl = domain.getDecl()) {
+        diagnoseDeclAvailability(domainDecl,
+                                 attr.getParsedAttr()->getDomainLoc(), nullptr,
+                                 where, std::nullopt);
+
+        if (!attr.isVersionSpecific()) {
+          // Check whether the availability domain is permanently enabled. If it
+          // is, suggest modifying or removing the attribute.
+          if (domain.isPermanentlyAlwaysEnabled()) {
+            auto parsedAttr = attr.getParsedAttr();
+            switch (parsedAttr->getKind()) {
+            case AvailableAttr::Kind::Default:
+              // This introduction constraint has no effect since it will never
+              // restrict use of the declaration. Provide a fix-it remove the
+              // attribute.
+              diagnoseAndRemoveAttr(
+                  D, attr.getParsedAttr(),
+                  diag::attr_availability_has_no_effect_domain_always_available,
+                  parsedAttr, domain);
+              break;
+            case AvailableAttr::Kind::Deprecated:
+            case AvailableAttr::Kind::NoAsync:
+            case AvailableAttr::Kind::Unavailable:
+              // Any other kind of constraint always constrains use of the
+              // declaration, so provide a fix-it to specify `*` instead of the
+              // custom domain.
+              ctx.Diags
+                  .diagnose(parsedAttr->getDomainLoc(),
+                            diag::attr_availability_domain_always_available,
+                            domain)
+                  .fixItReplace(parsedAttr->getDomainLoc(), "*");
+              break;
+            }
+          }
+        }
+      }
+    }
+  }
+
   void visit(Decl *D) {
     DeclVisitor<DeclAvailabilityChecker>::visit(D);
     checkGlobalActor(D);
+    checkAttachedMacros(D);
+    checkAvailabilityDomains(D);
   }
   
   // Force all kinds to be handled at a lower level.
@@ -2171,6 +2343,7 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
   UNREACHABLE(TopLevelCode, "not applicable")
   UNREACHABLE(Module, "not applicable")
   UNREACHABLE(Missing, "not applicable")
+  UNREACHABLE(Using, "not applicable")
 
   UNREACHABLE(Param, "handled by the enclosing declaration")
   UNREACHABLE(GenericTypeParam, "handled by the enclosing declaration")
@@ -2385,14 +2558,10 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
   }
 
   void checkConstrainedExtensionRequirements(ExtensionDecl *ED,
-                                             bool hasExportedMembers) {
+                                             ExportabilityReason reason) {
     if (!ED->getTrailingWhereClause())
       return;
 
-    ExportabilityReason reason =
-        hasExportedMembers ? ExportabilityReason::ExtensionWithPublicMembers
-                           : ExportabilityReason::ExtensionWithConditionalConformances;
-
     forAllRequirementTypes(ED, [&](Type type, TypeRepr *typeRepr) {
       checkType(type, typeRepr, ED, reason,
                 DeclAvailabilityFlag::DisableUnsafeChecking);
@@ -2436,7 +2605,11 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
     // the 'where' clause must only name exported types.
     Where = wasWhere.withExported(hasExportedMembers ||
                                   !ED->getInherited().empty());
-    checkConstrainedExtensionRequirements(ED, hasExportedMembers);
+    ExportabilityReason reason =
+        hasExportedMembers
+            ? ExportabilityReason::ExtensionWithPublicMembers
+            : ExportabilityReason::ExtensionWithConditionalConformances;
+    checkConstrainedExtensionRequirements(ED, reason);
 
     // If we haven't already visited the extended nominal visit it here.
     // This logic is too wide but prevents false reports of an unused public
@@ -2447,15 +2620,8 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
 
       // Remember that the module defining the extended type must be imported
       // publicly.
-      recordRequiredImportAccessLevelForDecl(
-          extendedType, DC, AccessLevel::Public,
-          [&](AttributedImport<ImportedModule> attributedImport) {
-            ModuleDecl *importedVia = attributedImport.module.importedModule,
-                       *sourceModule = ED->getModuleContext();
-            ED->diagnose(diag::module_api_import, ED, importedVia, sourceModule,
-                         importedVia == sourceModule,
-                         /*isImplicit*/ false);
-          });
+      recordRequiredImportAccessLevelForDecl(extendedType, DC,
+                                             AccessLevel::Public, ED->getLoc());
     }
   }
 
@@ -2482,7 +2648,7 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
                     );
     if (refRange.isValid())
       diag.highlight(refRange);
-    diag.flush();
+
     PGD->diagnose(diag::name_declared_here, PGD->getName());
   }
 
@@ -2511,7 +2677,7 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
 
 } // end anonymous namespace
 
-static void checkExtensionGenericParamAccess(const ExtensionDecl *ED) {
+static void checkExtensionAccess(const ExtensionDecl *ED) {
   auto *AA = ED->getAttrs().getAttribute<AccessControlAttr>();
   if (!AA)
     return;
@@ -2542,8 +2708,11 @@ static void checkExtensionGenericParamAccess(const ExtensionDecl *ED) {
     break;
   }
 
-  AccessControlChecker().checkGenericParamAccess(
-      ED, ED, desiredAccessScope, userSpecifiedAccess);
+  auto accessChecker = AccessControlChecker();
+  accessChecker.checkGenericParamAccess(ED, ED, desiredAccessScope,
+                                        userSpecifiedAccess);
+  accessChecker.checkAvailabilityDomains(ED, desiredAccessScope,
+                                         userSpecifiedAccess);
 }
 
 DisallowedOriginKind swift::getDisallowedOriginKind(const Decl *decl,
@@ -2563,6 +2732,11 @@ void swift::recordRequiredImportAccessLevelForDecl(
   if (definingModule == dc->getParentModule())
     return;
 
+  // Egregious hack: if the declaration is for a C++ namespace, assume it's
+  // accessible.
+  if (isa_and_nonnull<clang::NamespaceDecl>(decl->getClangDecl()))
+    return;
+
   sf->registerRequiredAccessLevelForModule(definingModule, accessLevel);
 
   if (auto attributedImport = sf->getImportAccessLevel(definingModule)) {
@@ -2581,6 +2755,23 @@ void swift::recordRequiredImportAccessLevelForDecl(
   }
 }
 
+void swift::recordRequiredImportAccessLevelForDecl(const ValueDecl *decl,
+                                                   const DeclContext *dc,
+                                                   AccessLevel accessLevel,
+                                                   SourceLoc loc) {
+  recordRequiredImportAccessLevelForDecl(
+      decl, dc, accessLevel,
+      [&](AttributedImport<ImportedModule> attributedImport) {
+        SourceLoc diagLoc =
+            loc.isValid() ? loc : extractNearestSourceLoc(dc);
+        ModuleDecl *importedVia = attributedImport.module.importedModule,
+                   *sourceModule = decl->getModuleContext();
+        dc->getASTContext().Diags.diagnose(
+            diagLoc, diag::module_api_import, decl, importedVia, sourceModule,
+            importedVia == sourceModule, loc.isInvalid());
+      });
+}
+
 void swift::diagnoseUnnecessaryPublicImports(SourceFile &SF) {
   ASTContext &ctx = SF.getASTContext();
   if (ctx.TypeCheckerOpts.SkipFunctionBodies != FunctionBodySkipping::None)
@@ -2651,15 +2842,8 @@ void registerPackageAccessForPackageExtendedType(ExtensionDecl *ED) {
 
   // Remember that the module defining the decl must be imported with at least
   // package visibility.
-  recordRequiredImportAccessLevelForDecl(
-      extendedType, DC, AccessLevel::Package,
-      [&](AttributedImport<ImportedModule> attributedImport) {
-        ModuleDecl *importedVia = attributedImport.module.importedModule,
-                   *sourceModule = ED->getModuleContext();
-        ED->diagnose(diag::module_api_import, ED, importedVia, sourceModule,
-                     importedVia == sourceModule,
-                     /*isImplicit*/ false);
-      });
+  recordRequiredImportAccessLevelForDecl(extendedType, DC, AccessLevel::Package,
+                                         ED->getLoc());
 }
 
 void swift::checkAccessControl(Decl *D) {
@@ -2669,13 +2853,10 @@ void swift::checkAccessControl(Decl *D) {
     AccessControlChecker(allowInlineable).visit(D);
     UsableFromInlineChecker().visit(D);
   } else if (auto *ED = dyn_cast<ExtensionDecl>(D)) {
-    checkExtensionGenericParamAccess(ED);
+    checkExtensionAccess(ED);
     registerPackageAccessForPackageExtendedType(ED);
   }
 
-  if (isa<AccessorDecl>(D))
-    return;
-
   auto where = ExportContext::forDeclSignature(D);
   if (where.isImplicit())
     return;
diff --git a/lib/Sema/TypeCheckAccess.h b/lib/Sema/TypeCheckAccess.h
index 6291c1de9d419..c97312b962370 100644
--- a/lib/Sema/TypeCheckAccess.h
+++ b/lib/Sema/TypeCheckAccess.h
@@ -47,6 +47,10 @@ enum class DisallowedOriginKind : uint8_t {
   SPIOnly,
   MissingImport,
   FragileCxxAPI,
+
+  /// An import that is internal via the internally-imported bridging header.
+  InternalBridgingHeaderImport,
+
   NonPublicImport,
   None
 };
diff --git a/lib/Sema/TypeCheckAccessNotes.cpp b/lib/Sema/TypeCheckAccessNotes.cpp
new file mode 100644
index 0000000000000..07b35cc17209c
--- /dev/null
+++ b/lib/Sema/TypeCheckAccessNotes.cpp
@@ -0,0 +1,254 @@
+//===--- TypeCheckAccessNotes.cpp - Type Checking for Access Notes --------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the implicit attribute transform caused by access notes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "TypeCheckDecl.h"
+#include "TypeCheckObjC.h"
+#include "TypeChecker.h"
+#include "swift/AST/ASTContext.h"
+#include "swift/AST/ASTPrinter.h"
+#include "swift/AST/Decl.h"
+#include "swift/AST/Module.h"
+#include "swift/AST/SourceFile.h"
+#include "swift/AST/TypeCheckRequests.h"
+#include "swift/Basic/LLVM.h"
+
+using namespace swift;
+
+static StringRef prettyPrintAttrs(const ValueDecl *VD,
+                                  ArrayRef<const DeclAttribute *> attrs,
+                                  SmallVectorImpl<char> &out) {
+  llvm::raw_svector_ostream os(out);
+  StreamPrinter printer(os);
+
+  PrintOptions opts = PrintOptions::printDeclarations();
+  VD->getAttrs().print(printer, opts, attrs, VD);
+  return StringRef(out.begin(), out.size()).drop_back();
+}
+
+static void diagnoseChangesByAccessNote(
+    ValueDecl *VD, ArrayRef<const DeclAttribute *> attrs,
+    Diag<StringRef, StringRef, const ValueDecl *> diagID,
+    Diag<StringRef> fixItID,
+    llvm::function_ref<void(InFlightDiagnostic, StringRef)> addFixIts) {
+  if (!VD->getASTContext().LangOpts.shouldRemarkOnAccessNoteSuccess() ||
+      attrs.empty())
+    return;
+
+  // Generate string containing all attributes.
+  SmallString<64> attrString;
+  auto attrText = prettyPrintAttrs(VD, attrs, attrString);
+
+  SourceLoc fixItLoc;
+
+  auto reason = VD->getModuleContext()->getAccessNotes()->Reason;
+  auto diag = VD->diagnose(diagID, reason, attrText, VD);
+  for (auto attr : attrs) {
+    diag.highlight(attr->getRangeWithAt());
+    if (fixItLoc.isInvalid())
+      fixItLoc = attr->getRangeWithAt().Start;
+  }
+
+  if (!fixItLoc)
+    fixItLoc = VD->getAttributeInsertionLoc(true);
+
+  addFixIts(VD->getASTContext().Diags.diagnose(fixItLoc, fixItID, attrText),
+            attrString);
+}
+
+template <typename Attr>
+static void addOrRemoveAttr(ValueDecl *VD, const AccessNotesFile &notes,
+                            std::optional<bool> expected,
+                            SmallVectorImpl<DeclAttribute *> &removedAttrs,
+                            llvm::function_ref<Attr *()> willCreate) {
+  if (!expected)
+    return;
+
+  auto attr = VD->getAttrs().getAttribute<Attr>();
+  if (*expected == (attr != nullptr))
+    return;
+
+  if (*expected) {
+    attr = willCreate();
+    attr->setAddedByAccessNote();
+    VD->getAttrs().add(attr);
+
+    // Arrange for us to emit a remark about this attribute after type checking
+    // has ensured it's valid.
+    if (auto SF = VD->getDeclContext()->getParentSourceFile())
+      SF->AttrsAddedByAccessNotes[VD].push_back(attr);
+  } else {
+    removedAttrs.push_back(attr);
+    VD->getAttrs().removeAttribute(attr);
+  }
+}
+
+InFlightDiagnostic swift::softenIfAccessNote(const Decl *D,
+                                             const DeclAttribute *attr,
+                                             InFlightDiagnostic &diag) {
+  const ValueDecl *VD = dyn_cast<ValueDecl>(D);
+  if (!VD || !attr || !attr->getAddedByAccessNote())
+    return std::move(diag);
+
+  SmallString<32> attrString;
+  auto attrText = prettyPrintAttrs(VD, llvm::ArrayRef(attr), attrString);
+
+  ASTContext &ctx = D->getASTContext();
+  auto behavior = ctx.LangOpts.getAccessNoteFailureLimit();
+  return std::move(diag.wrapIn(diag::wrap_invalid_attr_added_by_access_note,
+                               D->getModuleContext()->getAccessNotes()->Reason,
+                               ctx.AllocateCopy(attrText), VD)
+                       .limitBehavior(behavior));
+}
+
+static void applyAccessNote(ValueDecl *VD, const AccessNote &note,
+                            const AccessNotesFile &notes) {
+  ASTContext &ctx = VD->getASTContext();
+  SmallVector<DeclAttribute *, 2> removedAttrs;
+
+  addOrRemoveAttr<ObjCAttr>(VD, notes, note.ObjC, removedAttrs, [&] {
+    return ObjCAttr::create(ctx, note.ObjCName, false);
+  });
+
+  addOrRemoveAttr<DynamicAttr>(VD, notes, note.Dynamic, removedAttrs,
+                               [&] { return new (ctx) DynamicAttr(true); });
+
+  // FIXME: If we ever have more attributes, we'll need to sort removedAttrs by
+  // SourceLoc. As it is, attrs are always before modifiers, so we're okay now.
+
+  diagnoseChangesByAccessNote(VD, removedAttrs,
+                              diag::attr_removed_by_access_note,
+                              diag::fixit_attr_removed_by_access_note,
+                              [&](InFlightDiagnostic diag, StringRef code) {
+                                for (auto attr : llvm::reverse(removedAttrs))
+                                  diag.fixItRemove(attr->getRangeWithAt());
+                              });
+
+  if (note.ObjCName) {
+    auto newName = note.ObjCName.value();
+
+    // addOrRemoveAttr above guarantees there's an ObjCAttr on this decl.
+    auto attr = VD->getAttrs().getAttribute<ObjCAttr>();
+    assert(attr && "ObjCName set, but ObjCAttr not true or did not apply???");
+
+    if (!attr->hasName()) {
+      // There was already an @objc attribute with no selector. Set it.
+      attr->setName(newName, true);
+
+      if (!ctx.LangOpts.shouldRemarkOnAccessNoteSuccess())
+        return;
+
+      VD->diagnose(diag::attr_objc_name_changed_by_access_note, notes.Reason,
+                   VD, newName);
+
+      auto fixIt =
+          VD->diagnose(diag::fixit_attr_objc_name_changed_by_access_note);
+      fixDeclarationObjCName(fixIt, VD, ObjCSelector(), newName);
+    } else if (attr->getName() != newName) {
+      // There was already an @objc
+      auto behavior = ctx.LangOpts.getAccessNoteFailureLimit();
+
+      VD->diagnose(diag::attr_objc_name_conflicts_with_access_note,
+                   notes.Reason, VD, attr->getName().value(), newName)
+          .highlight(attr->getRangeWithAt())
+          .limitBehavior(behavior);
+    }
+  }
+}
+
+void TypeChecker::applyAccessNote(ValueDecl *VD) {
+  (void)evaluateOrDefault(VD->getASTContext().evaluator,
+                          ApplyAccessNoteRequest{VD}, {});
+}
+
+void swift::diagnoseAttrsAddedByAccessNote(SourceFile &SF) {
+  if (!SF.getASTContext().LangOpts.shouldRemarkOnAccessNoteSuccess())
+    return;
+
+  for (auto declAndAttrs : SF.AttrsAddedByAccessNotes) {
+    auto D = declAndAttrs.getFirst();
+    SmallVector<DeclAttribute *, 4> sortedAttrs;
+    llvm::append_range(sortedAttrs, declAndAttrs.getSecond());
+
+    // Filter out invalid attributes.
+    sortedAttrs.erase(llvm::remove_if(sortedAttrs,
+                                      [](DeclAttribute *attr) {
+                                        assert(attr->getAddedByAccessNote());
+                                        return attr->isInvalid();
+                                      }),
+                      sortedAttrs.end());
+    if (sortedAttrs.empty())
+      continue;
+
+    // Sort attributes by name.
+    llvm::sort(sortedAttrs, [](DeclAttribute *first, DeclAttribute *second) {
+      return first->getAttrName() < second->getAttrName();
+    });
+    sortedAttrs.erase(std::unique(sortedAttrs.begin(), sortedAttrs.end()),
+                      sortedAttrs.end());
+
+    diagnoseChangesByAccessNote(
+        D, sortedAttrs, diag::attr_added_by_access_note,
+        diag::fixit_attr_added_by_access_note,
+        [=](InFlightDiagnostic diag, StringRef code) {
+          diag.fixItInsert(D->getAttributeInsertionLoc(/*isModifier=*/true),
+                           code);
+        });
+  }
+}
+
+const AccessNotesFile *
+LoadAccessNotesRequest::evaluate(Evaluator &evaluator, ASTContext *_ctx) const {
+  auto &ctx = *_ctx;
+  auto &accessNotesPath = ctx.LangOpts.AccessNotesPath;
+  if (accessNotesPath.empty())
+    return nullptr;
+
+  auto &SM = ctx.SourceMgr;
+  auto &FS = *SM.getFileSystem();
+  auto bufferOrError = swift::vfs::getFileOrSTDIN(FS, accessNotesPath);
+  if (!bufferOrError) {
+    ctx.Diags.diagnose(SourceLoc(), diag::access_notes_file_io_error,
+                       accessNotesPath, bufferOrError.getError().message());
+    return nullptr;
+  }
+
+  int sourceID = SM.addNewSourceBuffer(std::move(bufferOrError.get()));
+  auto buffer = SM.getLLVMSourceMgr().getMemoryBuffer(sourceID);
+
+  auto accessNotesFile = AccessNotesFile::load(ctx, buffer);
+  if (!accessNotesFile)
+    return nullptr;
+
+  auto *result =
+      ctx.AllocateObjectCopy<AccessNotesFile>(std::move(*accessNotesFile));
+  ctx.addDestructorCleanup(*result);
+  return result;
+}
+
+evaluator::SideEffect ApplyAccessNoteRequest::evaluate(Evaluator &evaluator,
+                                                       ValueDecl *VD) const {
+  // Access notes don't apply to ABI-only attributes.
+  if (!ABIRoleInfo(VD).providesAPI())
+    return {};
+
+  auto *notes = VD->getModuleContext()->getAccessNotes();
+  if (!notes)
+    return {};
+
+  if (auto note = notes->lookup(VD))
+    applyAccessNote(VD, *note.get(), *notes);
+  return {};
+}
diff --git a/lib/Sema/TypeCheckAttr.cpp b/lib/Sema/TypeCheckAttr.cpp
index d7f2b76851f37..b005626ffe527 100644
--- a/lib/Sema/TypeCheckAttr.cpp
+++ b/lib/Sema/TypeCheckAttr.cpp
@@ -18,11 +18,15 @@
 #include "TypeCheckAvailability.h"
 #include "TypeCheckConcurrency.h"
 #include "TypeCheckDistributed.h"
+#include "TypeCheckEmbedded.h"
 #include "TypeCheckMacros.h"
 #include "TypeCheckObjC.h"
 #include "TypeCheckType.h"
 #include "TypeChecker.h"
+#include "swift/AST/ASTPrinter.h"
 #include "swift/AST/ASTVisitor.h"
+#include "swift/AST/Attr.h"
+#include "swift/AST/AttrKind.h"
 #include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/ConformanceLookup.h"
@@ -113,20 +117,32 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
     return true;
   }
 
-  void diagnoseIsolatedDeinitInValueTypes(DeclAttribute *attr) {
+  void checkIsolatedDeinitAttr(DeclAttribute *attr) {
     auto &C = D->getASTContext();
 
-    if (isa<DestructorDecl>(D)) {
-      if (auto nominal = dyn_cast<NominalTypeDecl>(D->getDeclContext())) {
-        if (!isa<ClassDecl>(nominal)) {
-          // only classes and actors can have isolated deinit.
-          diagnoseAndRemoveAttr(attr, diag::isolated_deinit_on_value_type);
-          return;
-        }
-      }
+    auto destructor = dyn_cast<DestructorDecl>(D);
+    if (!destructor)
+      return;
+
+    auto nominal = dyn_cast<NominalTypeDecl>(D->getDeclContext());
+    if (!nominal)
+      return;
+
+    if (!isa<ClassDecl>(nominal)) {
+      // only classes and actors can have isolated deinit.
+      diagnoseAndRemoveAttr(attr, diag::isolated_deinit_on_value_type);
+      return;
+    }
+
+    if (!getActorIsolation(nominal).isMainActor() && destructor->hasBody()) {
+      // In module emission jobs, type checking the body of the destructor may
+      // be skipped which means availability in the body cannot be diagnosed
+      // accurately.
+      if (destructor->isBodySkipped())
+        return;
 
       TypeChecker::checkAvailability(
-          attr->getRange(), C.getIsolatedDeinitAvailability(),
+          destructor->getBodySourceRange(), C.getIsolatedDeinitAvailability(),
           D->getDeclContext(),
           [&](AvailabilityDomain domain, AvailabilityRange range) {
             return diagnoseAndRemoveAttr(
@@ -146,6 +162,7 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
 
 #define IGNORED_ATTR(X) void visit##X##Attr(X##Attr *) {}
   IGNORED_ATTR(AlwaysEmitIntoClient)
+  IGNORED_ATTR(NeverEmitIntoClient)
   IGNORED_ATTR(HasInitialValue)
   IGNORED_ATTR(ClangImporterSynthesizedType)
   IGNORED_ATTR(Convenience)
@@ -155,7 +172,6 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
   IGNORED_ATTR(HasStorage)
   IGNORED_ATTR(HasMissingDesignatedInitializers)
   IGNORED_ATTR(InheritsConvenienceInitializers)
-  IGNORED_ATTR(Inline)
   IGNORED_ATTR(ObjCBridged)
   IGNORED_ATTR(ObjCNonLazyRealization)
   IGNORED_ATTR(ObjCRuntimeName)
@@ -184,7 +200,6 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
   IGNORED_ATTR(AtRethrows)
   IGNORED_ATTR(AtReasync)
   IGNORED_ATTR(ImplicitSelfCapture)
-  IGNORED_ATTR(InheritActorContext)
   IGNORED_ATTR(Preconcurrency)
   IGNORED_ATTR(BackDeployed)
   IGNORED_ATTR(Documentation)
@@ -198,7 +213,7 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
     TypeChecker::checkDeclABIAttribute(D, attr);
   }
 
-  void visitExecutionAttr(ExecutionAttr *attr) {
+  void checkExecutionBehaviorAttribute(DeclAttribute *attr) {
     auto *const decl = cast<ValueDecl>(D);
 
     auto *const storage = dyn_cast<AbstractStorageDecl>(decl);
@@ -208,7 +223,8 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
     }
 
     if (!decl->isAsync()) {
-      diagnoseAndRemoveAttr(attr, diag::attr_execution_only_on_async, decl);
+      diagnoseAndRemoveAttr(attr, diag::execution_behavior_only_on_async, attr,
+                            decl);
       return;
     }
 
@@ -224,20 +240,35 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
       // isolated parameters affect isolation of the function itself
       if (isa<IsolatedTypeRepr>(repr)) {
         diagnoseAndRemoveAttr(
-            attr, diag::attr_execution_incompatible_isolated_parameter, decl,
-            P);
+            attr, diag::execution_behavior_incompatible_isolated_parameter,
+            attr, decl, P);
         return;
       }
+    }
+  }
 
-      if (auto *attrType = dyn_cast<AttributedTypeRepr>(repr)) {
-        if (attrType->has(TypeAttrKind::Isolated)) {
-          diagnoseAndRemoveAttr(
-              attr,
-              diag::attr_execution_incompatible_dynamically_isolated_parameter,
-              decl, P);
-          return;
-        }
-      }
+  void visitNonexhaustiveAttr(NonexhaustiveAttr *attr) {
+    auto *E = cast<EnumDecl>(D);
+
+    if (D->getAttrs().hasAttribute<FrozenAttr>()) {
+      diagnoseAndRemoveAttr(attr, diag::nonexhaustive_attr_on_frozen_type);
+      return;
+    }
+
+    if (E->getFormalAccess() < AccessLevel::Package) {
+      diagnoseAndRemoveAttr(attr, diag::nonexhaustive_attr_on_internal_type,
+                            E->getName(), E->getFormalAccess());
+      return;
+    }
+  }
+
+  void visitConcurrentAttr(ConcurrentAttr *attr) {
+    checkExecutionBehaviorAttribute(attr);
+
+    if (auto *nonisolated = D->getAttrs().getAttribute<NonisolatedAttr>()) {
+      if (nonisolated->isNonSending())
+        diagnoseAndRemoveAttr(attr, diag::actor_isolation_multiple_attr_2, D,
+                              attr, nonisolated);
     }
   }
 
@@ -254,10 +285,11 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
 
     assert(!D->hasClangNode() && "@_borrowed on imported declaration?");
 
+    auto *ASD = cast<AbstractStorageDecl>(D);
+
     if (D->getAttrs().hasAttribute<DynamicAttr>()) {
-      diagnose(attr->getLocation(), diag::borrowed_with_objc_dynamic,
-               D->getDescriptiveKind())
-        .fixItRemove(attr->getRange());
+      diagnose(attr->getLocation(), diag::borrowed_with_objc_dynamic, ASD)
+          .fixItRemove(attr->getRange());
       D->getAttrs().removeAttribute(attr);
       return;
     }
@@ -266,8 +298,8 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
     auto protoDecl = dyn_cast<ProtocolDecl>(dc);
     if (protoDecl && protoDecl->isObjC()) {
       diagnose(attr->getLocation(), diag::borrowed_on_objc_protocol_requirement,
-               D->getDescriptiveKind())
-        .fixItRemove(attr->getRange());
+               ASD)
+          .fixItRemove(attr->getRange());
       D->getAttrs().removeAttribute(attr);
       return;
     }
@@ -366,11 +398,14 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
   void visitPostfixAttr(PostfixAttr *attr) { checkOperatorAttribute(attr); }
   void visitPrefixAttr(PrefixAttr *attr) { checkOperatorAttribute(attr); }
 
+  void visitSpecializedAttr(SpecializedAttr *attr);
   void visitSpecializeAttr(SpecializeAttr *attr);
+  void visitAbstractSpecializeAttr(AbstractSpecializeAttr *attr);
 
   void visitFixedLayoutAttr(FixedLayoutAttr *attr);
   void visitUsableFromInlineAttr(UsableFromInlineAttr *attr);
   void visitInlinableAttr(InlinableAttr *attr);
+  void visitInlineAttr(InlineAttr *attr);
   void visitOptimizeAttr(OptimizeAttr *attr);
   void visitExclusivityAttr(ExclusivityAttr *attr);
 
@@ -406,8 +441,10 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
   void visitNonisolatedAttr(NonisolatedAttr *attr);
   void visitIsolatedAttr(IsolatedAttr *attr);
 
+  void visitInheritActorContextAttr(InheritActorContextAttr *attr);
+
   void visitNoImplicitCopyAttr(NoImplicitCopyAttr *attr);
-  
+
   void visitAlwaysEmitConformanceMetadataAttr(AlwaysEmitConformanceMetadataAttr *attr);
 
   void visitExtractConstantsFromMembersAttr(ExtractConstantsFromMembersAttr *attr);
@@ -439,12 +476,14 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
   void visitUnsafeNonEscapableResultAttr(UnsafeNonEscapableResultAttr *attr);
 
   void visitStaticExclusiveOnlyAttr(StaticExclusiveOnlyAttr *attr);
+  void visitManualOwnershipAttr(ManualOwnershipAttr *attr);
   void visitWeakLinkedAttr(WeakLinkedAttr *attr);
   void visitSILGenNameAttr(SILGenNameAttr *attr);
   void visitLifetimeAttr(LifetimeAttr *attr);
   void visitAddressableSelfAttr(AddressableSelfAttr *attr);
   void visitAddressableForDependenciesAttr(AddressableForDependenciesAttr *attr);
   void visitUnsafeAttr(UnsafeAttr *attr);
+  void visitUnsafeSelfDependentResultAttr(UnsafeSelfDependentResultAttr *attr);
 };
 
 } // end anonymous namespace
@@ -459,6 +498,11 @@ void AttributeChecker::visitNoImplicitCopyAttr(NoImplicitCopyAttr *attr) {
     return;
   }
 
+  // Don't allow it to be combined with ManualOwnership.
+  if (D->getASTContext().LangOpts.hasFeature(Feature::ManualOwnership)) {
+    diagnoseAndRemoveAttr(attr, diag::attr_manual_ownership_noimplicitcopy);
+  }
+
   if (auto *funcDecl = dyn_cast<FuncDecl>(D)) {
     if (visitOwnershipAttr(attr))
       return;
@@ -535,6 +579,9 @@ void AttributeChecker::visitSensitiveAttr(SensitiveAttr *attr) {
 }
 
 void AttributeChecker::visitTransparentAttr(TransparentAttr *attr) {
+  if (attr->isImplicit())
+    return;
+
   DeclContext *dc = D->getDeclContext();
   // Protocol declarations cannot be transparent.
   if (isa<ProtocolDecl>(dc))
@@ -598,7 +645,7 @@ void AttributeChecker::visitMutationAttr(DeclAttribute *attr) {
       case SelfAccessKind::Mutating:
       case SelfAccessKind::NonMutating:
         diagnoseAndRemoveAttr(attr, diag::mutating_invalid_classes,
-                              attrModifier, FD->getDescriptiveKind(),
+                              attrModifier, FD,
                               DC->getSelfProtocolDecl() != nullptr);
         break;
       }
@@ -1082,6 +1129,11 @@ void AttributeChecker::visitLazyAttr(LazyAttr *attr) {
   // are already lazily initialized).
   if (VD->isStatic() || varDC->isModuleScopeContext())
     diagnoseAndRemoveAttr(attr, diag::lazy_on_already_lazy_global);
+
+  // 'lazy' can't be used in or with `@abi` because it has auxiliary decls.
+  auto abiRole = ABIRoleInfo(D);
+  if (!abiRole.providesABI() || !abiRole.providesAPI())
+    diagnoseAndRemoveAttr(attr, diag::attr_abi_no_lazy);
 }
 
 bool AttributeChecker::visitAbstractAccessControlAttr(
@@ -1188,8 +1240,8 @@ void AttributeChecker::visitAccessControlAttr(AccessControlAttr *attr) {
     AccessLevel typeAccess = nominal->getFormalAccess();
     if (attr->getAccess() > typeAccess) {
       diagnose(attr->getLocation(), diag::access_control_extension_more,
-               typeAccess, nominal->getDescriptiveKind(), attr->getAccess())
-        .fixItRemove(attr->getRange());
+               typeAccess, nominal, attr->getAccess())
+          .fixItRemove(attr->getRange());
       attr->setInvalid();
       return;
     }
@@ -1201,9 +1253,7 @@ void AttributeChecker::visitAccessControlAttr(AccessControlAttr *attr) {
       // end up being problematic.
       auto diag = diagnose(attr->getLocation(),
                            diag::access_control_ext_requirement_member_more,
-                           attr->getAccess(),
-                           D->getDescriptiveKind(),
-                           maxAccess);
+                           attr->getAccess(), D, maxAccess);
       swift::fixItAccess(diag, cast<ValueDecl>(D), maxAccess);
       return;
     }
@@ -1221,12 +1271,9 @@ void AttributeChecker::visitAccessControlAttr(AccessControlAttr *attr) {
         // least this accessible" checking for overrides and protocol
         // requirements.
       } else if (attr->getAccess() == defaultAccess) {
-        diagnose(attr->getLocation(),
-                 diag::access_control_ext_member_redundant,
-                 attr->getAccess(),
-                 D->getDescriptiveKind(),
-                 extAttr->getAccess())
-          .fixItRemove(attr->getRange());
+        diagnose(attr->getLocation(), diag::access_control_ext_member_redundant,
+                 attr->getAccess(), D, extAttr->getAccess())
+            .fixItRemove(attr->getRange());
       }
     } else {
       if (auto VD = dyn_cast<ValueDecl>(D)) {
@@ -1237,7 +1284,7 @@ void AttributeChecker::visitAccessControlAttr(AccessControlAttr *attr) {
             diagnose(attr->getLocation(),
                      diag::access_control_non_objc_open_member, VD)
                 .fixItReplace(attr->getRange(), "public")
-                .warnUntilSwiftVersion(7);
+                .warnUntilFutureSwiftVersion();
           }
         }
       }
@@ -1305,12 +1352,9 @@ void AttributeChecker::visitSetterAccessAttr(
     return;
 
   } else if (attr->getAccess() == getterAccess) {
-    diagnose(attr->getLocation(),
-             diag::access_control_setter_redundant,
-             attr->getAccess(),
-             D->getDescriptiveKind(),
-             getterAccess)
-      .fixItRemove(attr->getRange());
+    diagnose(attr->getLocation(), diag::access_control_setter_redundant,
+             attr->getAccess(), D, getterAccess)
+        .fixItRemove(attr->getRange());
     return;
   }
 }
@@ -1332,10 +1376,8 @@ void AttributeChecker::visitSPIAccessControlAttr(SPIAccessControlAttr *attr) {
     if (!canUseAttr(VD) &&
         !(storage && canUseAttr(storage)) &&
         !(DC && DC->isSPI())) {
-      diagnoseAndRemoveAttr(attr,
-                            diag::spi_attribute_on_non_public,
-                            declAccess,
-                            D->getDescriptiveKind());
+      diagnoseAndRemoveAttr(attr, diag::spi_attribute_on_non_public, declAccess,
+                            VD);
     }
 
     // Forbid stored properties marked SPI in frozen types.
@@ -1462,8 +1504,7 @@ void AttributeChecker::visitObjCAttr(ObjCAttr *attr) {
       error = diag::invalid_objc_decl_context;
     else if (auto accessor = dyn_cast<AccessorDecl>(func))
       if (!accessor->isGetterOrSetter()) {
-        auto declKind = accessor->getDescriptiveKind();
-        diagnoseAndRemoveAttr(attr, diag::objc_observing_accessor, declKind)
+        diagnoseAndRemoveAttr(attr, diag::objc_observing_accessor, accessor)
             .limitBehavior(behavior);
         reason.describe(D);
         return;
@@ -1515,11 +1556,11 @@ void AttributeChecker::visitObjCAttr(ObjCAttr *attr) {
         else {
           firstNameLoc = D->getLoc();
         }
-        softenIfAccessNote(D, attr,
-          diagnose(firstNameLoc, diag::objc_name_req_nullary,
-                   D->getDescriptiveKind())
-            .fixItRemoveChars(afterFirstNameLoc, attr->getRParenLoc())
-            .limitBehavior(behavior));
+        softenIfAccessNote(
+            D, attr,
+            diagnose(firstNameLoc, diag::objc_name_req_nullary, D)
+                .fixItRemoveChars(afterFirstNameLoc, attr->getRParenLoc())
+                .limitBehavior(behavior));
 
         correctNameUsingNewAttr(
             ObjCAttr::createNullary(Ctx, attr->AtLoc, attr->getLocation(),
@@ -1639,7 +1680,7 @@ static bool hasObjCImplementationFeature(Decl *D, ObjCImplementationAttr *attr,
   // syntax, or you're using Feature::CImplementation. Either way, no go.
   ctx.Diags.diagnose(attr->getLocation(), diag::requires_experimental_feature,
                      attr->getAttrName(), attr->isDeclModifier(),
-                     getFeatureName(requiredFeature));
+                     requiredFeature.getName());
   return false;
 }
 
@@ -1671,8 +1712,7 @@ visitObjCImplementationAttr(ObjCImplementationAttr *attr) {
     // If this is an extension, suggest '@objc'.
     if (auto ED = dyn_cast<ExtensionDecl>(D)) {
       auto diag = diagnose(attr->getLocation(),
-                           diag::make_decl_objc_for_implementation,
-                           D->getDescriptiveKind());
+                           diag::make_decl_objc_for_implementation, D);
 
       ObjCSelector correctSelector(Ctx, 0, {attr->CategoryName});
       fixDeclarationObjCName(diag, ED, ObjCSelector(), correctSelector);
@@ -1851,7 +1891,7 @@ void TypeChecker::checkDeclAttributes(Decl *D) {
             && !D->getASTContext().LangOpts.hasFeature(*feature)) {
         Checker.diagnoseAndRemoveAttr(attr, diag::requires_experimental_feature,
                                       attr->getAttrName(), false,
-                                      getFeatureName(*feature));
+                                      feature->getName());
         continue;
       }
     }
@@ -1951,7 +1991,7 @@ bool swift::isValidDynamicCallableMethod(FuncDecl *decl,
   auto dictConf = checkConformance(argType, dictLitProto);
   if (dictConf.isInvalid())
     return false;
-  auto keyType = dictConf.getTypeWitnessByName(argType, ctx.Id_Key);
+  auto keyType = dictConf.getTypeWitnessByName(ctx.Id_Key);
   return (bool) checkConformance(keyType, stringLitProtocol);
 }
 
@@ -2126,6 +2166,40 @@ visitDynamicMemberLookupAttr(DynamicMemberLookupAttr *attr) {
 
     if (candidates.empty()) {
       emitInvalidTypeDiagnostic(oneCandidate->getLoc());
+      return;
+    }
+
+    // Diagnose if there are no candidates that are sufficiently accessible.
+    auto requiredAccessScope = decl->getFormalAccessScope(/*useDC=*/nullptr);
+    auto accessDC = requiredAccessScope.getDeclContext();
+    auto inaccessibleCandidate = candidates.front().getValueDecl();
+    candidates.filter([&](LookupResultEntry entry, bool isOuter) -> bool {
+      return entry.getValueDecl()->isAccessibleFrom(accessDC);
+    });
+
+    if (candidates.empty()) {
+      auto futureVersion = version::Version::getFutureMajorLanguageVersion();
+      bool shouldError = ctx.isSwiftVersionAtLeast(futureVersion);
+
+      // Diagnose as an error in resilient modules regardless of language
+      // version since this will break the swiftinterface. Don't diagnose
+      // cases in existing swiftinterface files, though.
+      shouldError |= decl->getModuleContext()->isResilient() &&
+                     !decl->getDeclContext()->isInSwiftinterface();
+
+      auto diag = diagnose(inaccessibleCandidate->getLoc(),
+                            diag::dynamic_member_lookup_candidate_inaccessible,
+                            inaccessibleCandidate);
+      fixItAccess(diag, inaccessibleCandidate,
+                  requiredAccessScope.requiredAccessForDiagnostics(),
+                  /*isForSetter=*/false, /*useDefaultAccess=*/false,
+                  /*updateAttr=*/false);
+      diag.warnUntilSwiftVersionIf(!shouldError, futureVersion);
+
+      if (shouldError) {
+        attr->setInvalid();
+        return;
+      }
     }
 
     return;
@@ -2185,14 +2259,25 @@ static Decl *getEnclosingDeclForDecl(Decl *D) {
 }
 
 static std::optional<std::pair<SemanticAvailableAttr, const Decl *>>
-getSemanticAvailableRangeDeclAndAttr(const Decl *decl) {
-  if (auto attr = decl->getAvailableAttrForPlatformIntroduction(
-          /*checkExtension=*/false))
-    return std::make_pair(*attr, decl);
+getSemanticAvailableRangeDeclAndAttr(const Decl *decl,
+                                     AvailabilityDomain domain) {
+  auto &ctx = decl->getASTContext();
+  AvailabilityConstraintFlags flags =
+      AvailabilityConstraintFlag::SkipEnclosingExtension;
+  if (auto constraint = swift::getAvailabilityConstraintForDeclInDomain(
+          decl, AvailabilityContext::forAlwaysAvailable(ctx), domain, flags)) {
+    switch (constraint->getReason()) {
+    case AvailabilityConstraint::Reason::UnavailableUnconditionally:
+    case AvailabilityConstraint::Reason::UnavailableObsolete:
+      break;
+    case AvailabilityConstraint::Reason::UnavailableUnintroduced:
+    case AvailabilityConstraint::Reason::Unintroduced:
+      return std::make_pair(constraint->getAttr(), decl);
+    }
+  }
 
-  if (auto *parent =
-          AvailabilityInference::parentDeclForInferredAvailability(decl))
-    return getSemanticAvailableRangeDeclAndAttr(parent);
+  if (auto *parent = decl->parentDeclForAvailability())
+    return getSemanticAvailableRangeDeclAndAttr(parent, domain);
 
   return std::nullopt;
 }
@@ -2235,8 +2320,7 @@ void AttributeChecker::visitAvailableAttr(AvailableAttr *parsedAttr) {
             vd);
       } else {
         D->getASTContext().Diags.diagnose(
-            D->getLoc(), diag::async_decl_must_be_available_from_async,
-            D->getDescriptiveKind());
+            D->getLoc(), diag::async_decl_must_be_available_from_async, D);
       }
     }
 
@@ -2287,7 +2371,7 @@ void AttributeChecker::visitAvailableAttr(AvailableAttr *parsedAttr) {
 
   if (auto *parent = getEnclosingDeclForDecl(D)) {
     if (auto enclosingAvailable =
-            getSemanticAvailableRangeDeclAndAttr(parent)) {
+            getSemanticAvailableRangeDeclAndAttr(parent, attr->getDomain())) {
       SemanticAvailableAttr enclosingAttr = enclosingAvailable->first;
       const Decl *enclosingDecl = enclosingAvailable->second;
       enclosingIntroducedRange = enclosingAttr.getIntroducedRange(Ctx);
@@ -2306,14 +2390,12 @@ void AttributeChecker::visitAvailableAttr(AvailableAttr *parsedAttr) {
         }
         diagnose(D->isImplicit() ? enclosingDecl->getLoc()
                                  : parsedAttr->getLocation(),
-                 diag::availability_decl_more_than_enclosing,
-                 D->getDescriptiveKind())
+                 diag::availability_decl_more_than_enclosing, D)
             .limitBehavior(limit);
         if (D->isImplicit())
           diagnose(enclosingDecl->getLoc(),
-                   diag::availability_implicit_decl_here,
-                   D->getDescriptiveKind(), Ctx.getTargetAvailabilityDomain(),
-                   *introducedRange);
+                   diag::availability_implicit_decl_here, D,
+                   Ctx.getTargetAvailabilityDomain(), *introducedRange);
         diagnose(enclosingDecl->getLoc(),
                  diag::availability_decl_more_than_enclosing_here,
                  Ctx.getTargetAvailabilityDomain(), *enclosingIntroducedRange);
@@ -2355,16 +2437,36 @@ static bool canDeclareSymbolName(StringRef symbol, ModuleDecl *fromModule) {
 void AttributeChecker::visitCDeclAttr(CDeclAttr *attr) {
   // Only top-level func decls are currently supported.
   if (D->getDeclContext()->isTypeContext())
-    diagnose(attr->getLocation(), diag::cdecl_not_at_top_level);
+    diagnose(attr->getLocation(), diag::cdecl_not_at_top_level,
+             attr);
 
-  // The name must not be empty.
-  if (attr->Name.empty())
-    diagnose(attr->getLocation(), diag::cdecl_empty_name);
+  // @_cdecl name must not be empty.
+  if (attr->Name.empty() && attr->Underscored)
+    diagnose(attr->getLocation(), diag::cdecl_empty_name,
+             attr);
 
   // The standard library can use @_cdecl to implement runtime functions.
-  if (!canDeclareSymbolName(attr->Name, D->getModuleContext())) {
+  auto VD = dyn_cast<ValueDecl>(D);
+  if (VD && !canDeclareSymbolName(VD->getCDeclName(), D->getModuleContext())) {
       diagnose(attr->getLocation(), diag::reserved_runtime_symbol_name,
-               attr->Name);
+               VD->getCDeclName());
+  }
+
+  // @_cdecl was never accepted on enums. Keep the previous diagnostic.
+  if (isa<EnumDecl>(D) && attr->Underscored) {
+    diagnose(attr->getLocation(), diag::attr_only_one_decl_kind,
+             attr, "func");
+  }
+
+  // Reject using both @c and @objc on the same decl.
+  if (D->getAttrs().getAttribute<ObjCAttr>()) {
+    diagnose(attr->getLocation(), diag::cdecl_incompatible_with_objc, D);
+  }
+
+  // @c needs to be enabled via a feature flag.
+  if (!attr->Underscored &&
+      !Ctx.LangOpts.hasFeature(Feature::CDecl)) {
+    diagnose(attr->getLocation(), diag::cdecl_feature_required);
   }
 }
 
@@ -2376,6 +2478,14 @@ void AttributeChecker::visitExposeAttr(ExposeAttr *attr) {
       diagnose(attr->getLocation(), diag::expose_wasm_not_at_top_level_func);
     break;
   }
+  case ExposureKind::NotCxx:
+    for (const auto *attr : D->getAttrs().getAttributes<ExposeAttr>())
+      if (attr->getExposureKind() == ExposureKind::Cxx)
+        diagnose(attr->getLocation(), diag::expose_only_non_other_attr,
+                 "@_expose(Cxx)");
+    if (!attr->Name.empty())
+      diagnose(attr->getLocation(), diag::expose_redundant_name_provided);
+    break;
   case ExposureKind::Cxx: {
     auto *VD = cast<ValueDecl>(D);
     // Expose cannot be mixed with '@_cdecl' declarations.
@@ -2559,8 +2669,7 @@ void AttributeChecker::visitSILGenNameAttr(SILGenNameAttr *A) {
   }
 
   if (D->getAttrs().hasAttribute<ABIAttr>()) {
-    diagnoseAndRemoveAttr(A, diag::attr_abi_incompatible_with_silgen_name,
-                          D->getDescriptiveKind());
+    diagnoseAndRemoveAttr(A, diag::attr_abi_incompatible_with_silgen_name, D);
   }
 }
 
@@ -2656,8 +2765,7 @@ void AttributeChecker::visitFinalAttr(FinalAttr *attr) {
   // Reject combining 'final' with 'open'.
   if (auto accessAttr = D->getAttrs().getAttribute<AccessControlAttr>()) {
     if (accessAttr->getAccess() == AccessLevel::Open) {
-      diagnose(attr->getLocation(), diag::open_decl_cannot_be_final,
-               D->getDescriptiveKind());
+      diagnose(attr->getLocation(), diag::open_decl_cannot_be_final, D);
       return;
     }
   }
@@ -3033,6 +3141,36 @@ synthesizeMainBody(AbstractFunctionDecl *fn, void *arg) {
   return std::make_pair(body, /*typechecked=*/false);
 }
 
+static llvm::SmallString<128>
+generateMainFunctionText(ASTContext &C, NominalTypeDecl *parentDecl,
+                         bool isThrows, bool isAsync) {
+  StringRef ExtraIndent;
+  StringRef CurrentIndent = Lexer::getIndentationForLine(
+      C.SourceMgr, parentDecl->getStartLoc(), &ExtraIndent);
+  std::string MethodIndent = (CurrentIndent + ExtraIndent).str();
+
+  llvm::SmallString<128> Text;
+  llvm::raw_svector_ostream OS(Text);
+  ExtraIndentStreamPrinter Printer(OS, MethodIndent);
+
+  Printer.printNewline();
+
+  Printer << "static func main() ";
+  if (isAsync)
+    Printer << "async ";
+  if (isThrows)
+    Printer << "throws ";
+
+  // Print the "{ <#code#> }" placeholder body.
+  Printer << "{\n";
+  Printer.printIndent();
+  Printer << ExtraIndent << getCodePlaceholder();
+  Printer.printNewline();
+  Printer << "}\n";
+
+  return Text;
+}
+
 FuncDecl *
 SynthesizeMainFunctionRequest::evaluate(Evaluator &evaluator,
                                         Decl *D) const {
@@ -3162,9 +3300,43 @@ SynthesizeMainFunctionRequest::evaluate(Evaluator &evaluator,
     const bool hasAsyncSupport =
         AvailabilityRange::forDeploymentTarget(context).isContainedIn(
             context.getBackDeployedConcurrencyAvailability());
-    context.Diags.diagnose(attr->getLocation(),
-                           diag::attr_MainType_without_main,
-                           nominal, hasAsyncSupport);
+
+    auto location = attr->getLocation();
+    auto fixLocation = braces.Start;
+
+    context.Diags.diagnose(location, diag::attr_MainType_without_main, nominal,
+                           hasAsyncSupport);
+
+    // Offer fix-its to add the `main` function for different combinations of
+    // effects, starting with no effects.
+
+    context.Diags.diagnose(location, diag::note_add_main_sync)
+        .fixItInsertAfter(fixLocation, generateMainFunctionText(
+                                           context, nominal, /*isThrows*/ false,
+                                           /*isAsync*/ false)
+                                           .str());
+
+    context.Diags.diagnose(location, diag::note_add_main_sync_throws)
+        .fixItInsertAfter(fixLocation, generateMainFunctionText(
+                                           context, nominal, /*isThrows*/ true,
+                                           /*isAsync*/ false)
+                                           .str());
+
+    if (hasAsyncSupport) {
+      context.Diags.diagnose(location, diag::note_add_main_async)
+          .fixItInsertAfter(fixLocation,
+                            generateMainFunctionText(context, nominal,
+                                                     /*isThrows*/ false,
+                                                     /*isAsync*/ true)
+                                .str());
+
+      context.Diags.diagnose(location, diag::note_add_main_async_throws)
+          .fixItInsertAfter(fixLocation,
+                            generateMainFunctionText(context, nominal,
+                                                     /*isThrows*/ true,
+                                                     /*isAsync*/ true)
+                                .str());
+    }
     attr->setInvalid();
     return nullptr;
   }
@@ -3292,7 +3464,7 @@ void AttributeChecker::visitRethrowsAttr(RethrowsAttr *attr) {
 
 /// Ensure that the requirements provided by the @_specialize attribute
 /// can be supported by the SIL EagerSpecializer pass.
-static void checkSpecializeAttrRequirements(SpecializeAttr *attr,
+static void checkSpecializeAttrRequirements(AbstractSpecializeAttr *attr,
                                             GenericSignature originalSig,
                                             GenericSignature specializedSig,
                                             ASTContext &ctx) {
@@ -3302,7 +3474,8 @@ static void checkSpecializeAttrRequirements(SpecializeAttr *attr,
   for (auto specializedReq : specializedReqs) {
     if (!specializedReq.getFirstType()->is<GenericTypeParamType>()) {
       ctx.Diags.diagnose(attr->getLocation(),
-                         diag::specialize_attr_only_generic_param_req);
+                         diag::specialize_attr_only_generic_param_req,
+												 attr->isPublic());
       hadError = true;
       continue;
     }
@@ -3314,14 +3487,17 @@ static void checkSpecializeAttrRequirements(SpecializeAttr *attr,
     case RequirementKind::Conformance:
     case RequirementKind::Superclass:
       ctx.Diags.diagnose(attr->getLocation(),
-                         diag::specialize_attr_unsupported_kind_of_req);
+                         attr->isPublic() ?
+												 diag::specialized_attr_unsupported_kind_of_req :
+												 diag::specialize_attr_unsupported_kind_of_req);
       hadError = true;
       break;
 
     case RequirementKind::SameType:
       if (specializedReq.getSecondType()->isTypeParameter()) {
         ctx.Diags.diagnose(attr->getLocation(),
-                           diag::specialize_attr_non_concrete_same_type_req);
+                           diag::specialize_attr_non_concrete_same_type_req,
+													 attr->isPublic());
         hadError = true;
       }
       break;
@@ -3359,38 +3535,48 @@ static void checkSpecializeAttrRequirements(SpecializeAttr *attr,
 
   ctx.Diags.diagnose(
       attr->getLocation(), diag::specialize_attr_type_parameter_count_mismatch,
-      gotCount, expectedCount);
+      gotCount, expectedCount, attr->isPublic());
 
   for (auto paramTy : unspecializedParams) {
     ctx.Diags.diagnose(attr->getLocation(),
                        diag::specialize_attr_missing_constraint,
-                       paramTy->getName());
+                       paramTy->getName(),
+											 attr->isPublic());
   }
 }
 
-/// Type check that a set of requirements provided by @_specialize.
+/// Type check that a set of requirements provided by @_specialize/@specialize.
 /// Store the set of requirements in the attribute.
+void AttributeChecker::visitSpecializedAttr(SpecializedAttr *attr) {
+  visitAbstractSpecializeAttr(attr);
+}
 void AttributeChecker::visitSpecializeAttr(SpecializeAttr *attr) {
+  visitAbstractSpecializeAttr(attr);
+}
+void AttributeChecker::visitAbstractSpecializeAttr(AbstractSpecializeAttr *attr) {
   auto *FD = cast<AbstractFunctionDecl>(D);
   auto genericSig = FD->getGenericSignature();
   auto *trailingWhereClause = attr->getTrailingWhereClause();
 
   if (!trailingWhereClause) {
     // Report a missing "where" clause.
-    diagnose(attr->getLocation(), diag::specialize_missing_where_clause);
+    diagnose(attr->getLocation(), diag::specialize_missing_where_clause,
+						 attr->isPublic());
     return;
   }
 
   if (trailingWhereClause->getRequirements().empty()) {
     // Report an empty "where" clause.
-    diagnose(attr->getLocation(), diag::specialize_empty_where_clause);
+    diagnose(attr->getLocation(), diag::specialize_empty_where_clause,
+						 attr->isPublic());
     return;
   }
 
   if (!genericSig) {
     // Only generic functions are permitted to have trailing where clauses.
     diagnose(attr->getLocation(),
-             diag::specialize_attr_nongeneric_trailing_where, FD->getName())
+             diag::specialize_attr_nongeneric_trailing_where, FD->getName(),
+             attr->isPublic())
         .highlight(trailingWhereClause->getSourceRange());
     return;
   }
@@ -3401,7 +3587,7 @@ void AttributeChecker::visitSpecializeAttr(SpecializeAttr *attr) {
 GenericSignature
 SerializeAttrGenericSignatureRequest::evaluate(Evaluator &evaluator,
                                                const AbstractFunctionDecl *FD,
-                                               SpecializeAttr *attr) const {
+                                               AbstractSpecializeAttr *attr) const {
   if (attr->specializedSignature)
     return attr->specializedSignature;
 
@@ -3427,26 +3613,25 @@ SerializeAttrGenericSignatureRequest::evaluate(Evaluator &evaluator,
   // Check the validity of provided requirements.
   checkSpecializeAttrRequirements(attr, genericSig, specializedSig, Ctx);
 
-  if (Ctx.LangOpts.hasFeature(Feature::LayoutPrespecialization)) {
-    llvm::SmallVector<Type, 4> typeErasedParams;
-    for (const auto &reqRepr :
-         attr->getTrailingWhereClause()->getRequirements()) {
-      if (reqRepr.getKind() == RequirementReprKind::LayoutConstraint) {
-        if (auto *attributedTy = dyn_cast<AttributedTypeRepr>(reqRepr.getSubjectRepr())) {
-          if (attributedTy->has(TypeAttrKind::NoMetadata)) {
-            const auto resolution = TypeResolution::forInterface(
-                FD->getDeclContext(), genericSig, std::nullopt,
-                /*unboundTyOpener*/ nullptr,
-                /*placeholderHandler*/ nullptr,
-                /*packElementOpener*/ nullptr);
-            const auto ty = resolution.resolveType(attributedTy);
-            typeErasedParams.push_back(ty);
-          }
+  llvm::SmallVector<Type, 4> typeErasedParams;
+  for (const auto &reqRepr :
+       attr->getTrailingWhereClause()->getRequirements()) {
+    if (reqRepr.getKind() == RequirementReprKind::LayoutConstraint) {
+      if (auto *attributedTy =
+              dyn_cast<AttributedTypeRepr>(reqRepr.getSubjectRepr())) {
+        if (attributedTy->has(TypeAttrKind::NoMetadata)) {
+          const auto resolution = TypeResolution::forInterface(
+              FD->getDeclContext(), genericSig, std::nullopt,
+              /*unboundTyOpener*/ nullptr,
+              /*placeholderHandler*/ nullptr,
+              /*packElementOpener*/ nullptr);
+          const auto ty = resolution.resolveType(attributedTy);
+          typeErasedParams.push_back(ty);
         }
       }
     }
-    attr->setTypeErasedParams(typeErasedParams);
   }
+  attr->setTypeErasedParams(typeErasedParams);
 
   // Check the target function if there is one.
   attr->getTargetFunctionDecl(FD);
@@ -3457,7 +3642,7 @@ SerializeAttrGenericSignatureRequest::evaluate(Evaluator &evaluator,
 std::optional<GenericSignature>
 SerializeAttrGenericSignatureRequest::getCachedResult() const {
   const auto &storage = getStorage();
-  SpecializeAttr *attr = std::get<1>(storage);
+  AbstractSpecializeAttr *attr = std::get<1>(storage);
   if (auto signature = attr->specializedSignature)
     return signature;
   return std::nullopt;
@@ -3466,7 +3651,7 @@ SerializeAttrGenericSignatureRequest::getCachedResult() const {
 void SerializeAttrGenericSignatureRequest::cacheResult(
     GenericSignature signature) const {
   const auto &storage = getStorage();
-  SpecializeAttr *attr = std::get<1>(storage);
+  AbstractSpecializeAttr *attr = std::get<1>(storage);
   attr->specializedSignature = signature;
 }
 
@@ -3513,6 +3698,55 @@ void AttributeChecker::visitUsableFromInlineAttr(UsableFromInlineAttr *attr) {
   }
 }
 
+void AttributeChecker::visitInlineAttr(InlineAttr *attr) {
+  if (attr->getKind() == InlineKind::Always &&
+      !Ctx.LangOpts.hasFeature(Feature::InlineAlways)) {
+    diagnoseAndRemoveAttr(attr, diag::attr_inline_always_experimental);
+    return;
+  }
+
+  if (attr->getKind() != InlineKind::Always)
+    return;
+
+  // Can't have @inline(always) on @usableFromInline.
+  auto *VD = cast<ValueDecl>(D);
+  if (VD->getAttrs().hasAttribute<UsableFromInlineAttr>()) {
+    diagnoseAndRemoveAttr(attr, diag::attr_inline_always_no_usable_from_inline);
+    return;
+  }
+  // Check that @inline(always) is only used on statically dispatched methods
+  // (final, static, and methods in extensions mostly).
+  bool isAccessorDecl = false;
+  if (auto *accessorDecl = dyn_cast<AccessorDecl>(D)) {
+    VD = accessorDecl->getStorage();
+    isAccessorDecl = true;
+  }
+
+  auto dc = dyn_cast<ClassDecl>(VD->getDeclContext());
+  if (!dc)
+   return;
+  // In a `class` context.
+
+  if (dc->isActor())
+    return;
+
+  if (auto *vd = dyn_cast<VarDecl>(VD)) {
+    if (vd->isFinal())
+      return;
+    if (isAccessorDecl) {
+      diagnoseAndRemoveAttr(attr, diag::attr_inline_always_on_accessor);
+    } else {
+      diagnoseAndRemoveAttr(attr, diag::attr_inline_always_requires_final_method,
+                            vd->getName(), true/*isVar*/);
+    }
+  } else if (auto *afd = dyn_cast<AbstractFunctionDecl>(VD)) {
+    if (afd->isFinal())
+      return;
+    diagnoseAndRemoveAttr(attr, diag::attr_inline_always_requires_final_method,
+                              afd->getName(), false/*isVar*/);
+  }
+}
+
 void AttributeChecker::visitInlinableAttr(InlinableAttr *attr) {
   // @inlinable cannot be applied to stored properties.
   //
@@ -3900,7 +4134,7 @@ findReplacedFunction(DeclNameRef replacedFunctionName,
 static AbstractFunctionDecl *
 findTargetFunction(DeclNameRef targetFunctionName,
                    const AbstractFunctionDecl *base,
-                   SpecializeAttr * attr, DiagnosticEngine *diags) {
+                   AbstractSpecializeAttr * attr, DiagnosticEngine *diags) {
   return findSimilarFunction(targetFunctionName, base, attr, diags,
                              false /*forDynamicReplacement*/);
 }
@@ -4250,8 +4484,25 @@ void AttributeChecker::visitImplementsAttr(ImplementsAttr *attr) {
   ProtocolDecl *PD = attr->getProtocol(DC);
 
   if (!PD) {
-    diagnose(attr->getLocation(), diag::implements_attr_non_protocol_type)
-      .highlight(attr->getProtocolTypeRepr()->getSourceRange());
+    // `ImplementsAttr::getProtocol()` returns `nullptr` both when a type fails
+    // to resolve, and when it resolves to something other than a protocol.
+    // Due to layering concerns, it doesn't resolve in a way that emits
+    // diagnostics.
+    //
+    // Distinguish between these situations by trying to resolve the type again.
+    // If it doesn't resolve, TypeResolution will have diagnosed the problem; if
+    // it does, it must have resolved to a non-protocol, so emit a diagnostic to
+    // that effect.
+    TypeResolutionOptions options(TypeResolverContext::None);
+    auto resolvedType = TypeResolution::resolveContextualType(
+        attr->getProtocolTypeRepr(), DC, options,
+        // Unbound generics and placeholders are not allowed within this attr.
+        /*unboundTyOpener*/ nullptr, /*placeholderHandler*/ nullptr,
+        /*packElementOpener*/ nullptr);
+
+    if (resolvedType && !resolvedType->hasError())
+      diagnose(attr->getLocation(), diag::implements_attr_non_protocol_type)
+        .highlight(attr->getProtocolTypeRepr()->getSourceRange());
     return;
   }
 
@@ -4314,7 +4565,7 @@ static void checkGlobalActorAttr(
     std::pair<CustomAttr *, NominalTypeDecl *> &globalActorAttr) {
   auto isolatedAttr = decl->getAttrs().getAttribute<IsolatedAttr>();
   auto nonisolatedAttr = decl->getAttrs().getAttribute<NonisolatedAttr>();
-  auto executionAttr = decl->getAttrs().getAttribute<ExecutionAttr>();
+  auto concurrentAttr = decl->getAttrs().getAttribute<ConcurrentAttr>();
 
   llvm::SmallVector<const DeclAttribute *, 2> attributes;
 
@@ -4326,10 +4577,9 @@ static void checkGlobalActorAttr(
   if (nonisolatedAttr) {
     attributes.push_back(nonisolatedAttr);
   }
-  if (executionAttr) {
-    attributes.push_back(executionAttr);
+  if (concurrentAttr) {
+    attributes.push_back(concurrentAttr);
   }
-
   if (attributes.size() == 1)
     return;
 
@@ -4338,7 +4588,6 @@ static void checkGlobalActorAttr(
                    attributes[1])
         .highlight(attributes[0]->getRangeWithAt())
         .highlight(attributes[1]->getRangeWithAt())
-        .warnUntilSwiftVersion(6)
         .fixItRemove(attributes[1]->getRangeWithAt());
     return;
   }
@@ -4349,7 +4598,6 @@ static void checkGlobalActorAttr(
         .highlight(attributes[0]->getRangeWithAt())
         .highlight(attributes[1]->getRangeWithAt())
         .highlight(attributes[2]->getRangeWithAt())
-        .warnUntilSwiftVersion(6)
         .fixItRemove(attributes[1]->getRangeWithAt())
         .fixItRemove(attributes[2]->getRangeWithAt());
     return;
@@ -4362,7 +4610,6 @@ static void checkGlobalActorAttr(
       .highlight(attributes[1]->getRangeWithAt())
       .highlight(attributes[2]->getRangeWithAt())
       .highlight(attributes[3]->getRangeWithAt())
-      .warnUntilSwiftVersion(6)
       .fixItRemove(attributes[1]->getRangeWithAt())
       .fixItRemove(attributes[2]->getRangeWithAt())
       .fixItRemove(attributes[3]->getRangeWithAt());
@@ -4385,11 +4632,16 @@ void AttributeChecker::visitCustomAttr(CustomAttr *attr) {
         auto role = roleAttr->getMacroRole();
         if (isInvalidAttachedMacro(role, D)) {
           diagnoseAndRemoveAttr(attr, diag::macro_attached_to_invalid_decl,
-                                getMacroRoleString(role),
-                                D->getDescriptiveKind(), D);
+                                getMacroRoleString(role), D);
         }
       }
 
+      // Macros can't be attached to ABI-only decls. (If we diagnosed above,
+      // don't bother with this.)
+      if (attr->isValid() && !ABIRoleInfo(D).providesAPI()) {
+        diagnoseAndRemoveAttr(attr, diag::attr_abi_no_macros, macro);
+      }
+
       return;
     }
 
@@ -4415,7 +4667,8 @@ void AttributeChecker::visitCustomAttr(CustomAttr *attr) {
       llvm::raw_string_ostream out(typeName);
       typeRepr->print(out);
 
-      Ctx.Diags.diagnose(attr->getLocation(), diag::unknown_attribute, typeName);
+      Ctx.Diags.diagnose(attr->getLocation(), diag::unknown_attr_name,
+                         typeName);
     }
 
     attr->setInvalid();
@@ -4454,11 +4707,10 @@ void AttributeChecker::visitCustomAttr(CustomAttr *attr) {
 
     if (isa<ParamDecl>(D)) {
       // Check for unsupported declarations.
-      auto *context = D->getDeclContext()->getAsDecl();
+      auto *context = cast_or_null<ValueDecl>(D->getDeclContext()->getAsDecl());
       if (isa_and_nonnull<SubscriptDecl>(context)) {
         diagnose(attr->getLocation(),
-                 diag::property_wrapper_param_not_supported,
-                 context->getDescriptiveKind());
+                 diag::property_wrapper_param_not_supported, context);
         attr->setInvalid();
         return;
       }
@@ -4471,16 +4723,25 @@ void AttributeChecker::visitCustomAttr(CustomAttr *attr) {
   // function, storage with an explicit getter, or parameter of function type.
   if (nominal->getAttrs().hasAttribute<ResultBuilderAttr>()) {
     ValueDecl *decl;
+    ValueDecl *abiRelevantDecl;
     if (auto param = dyn_cast<ParamDecl>(D)) {
       decl = param;
+      abiRelevantDecl = dyn_cast<ValueDecl>(
+                            param->getDeclContext()->getAsDecl());
     } else if (auto func = dyn_cast<FuncDecl>(D)) {
       decl = func;
+      abiRelevantDecl = func;
     } else if (auto storage = dyn_cast<AbstractStorageDecl>(D)) {
       decl = storage;
+      abiRelevantDecl = storage;
 
       // Check whether this is a storage declaration that is not permitted
       // to have a result builder attached.
       auto shouldDiagnose = [&]() -> bool {
+        // We'll diagnose use in @abi later.
+        if (!ABIRoleInfo(abiRelevantDecl).providesAPI())
+          return false;
+
         // An uninitialized stored property in a struct can have a function
         // builder attached.
         if (auto var = dyn_cast<VarDecl>(decl)) {
@@ -4524,6 +4785,14 @@ void AttributeChecker::visitCustomAttr(CustomAttr *attr) {
       return;
     }
 
+    // Result builders shouldn't be applied to an ABI-only decl because they
+    // have no ABI effect.
+    if (!ABIRoleInfo(abiRelevantDecl).providesAPI()) {
+      diagnoseAndRemoveAttr(attr, diag::attr_abi_forbidden_attr,
+                            nominal->getNameStr(), /*isModifier=*/false);
+      return;
+    }
+
     // Diagnose and ignore arguments.
     if (attr->hasArgs()) {
       diagnose(attr->getLocation(), diag::result_builder_arguments)
@@ -4550,7 +4819,7 @@ void AttributeChecker::visitCustomAttr(CustomAttr *attr) {
   // If the nominal type is a global actor, let the global actor attribute
   // retrieval request perform checking for us.
   if (nominal->isGlobalActor()) {
-    diagnoseIsolatedDeinitInValueTypes(attr);
+    checkIsolatedDeinitAttr(attr);
     if (auto g = D->getGlobalActorAttr()) {
       checkGlobalActorAttr(D, *g);
     }
@@ -4803,13 +5072,6 @@ AttributeChecker::visitSPIOnlyAttr(SPIOnlyAttr *attr) {
 }
 
 void AttributeChecker::visitNoMetadataAttr(NoMetadataAttr *attr) {
-  if (!Ctx.LangOpts.hasFeature(Feature::LayoutPrespecialization)) {
-    auto error =
-        diag::experimental_no_metadata_feature_can_only_be_used_when_enabled;
-    diagnoseAndRemoveAttr(attr, error);
-    return;
-  }
-
   if (!isa<GenericTypeParamDecl>(D)) {
     attr->setInvalid();
     diagnoseAndRemoveAttr(attr, diag::no_metadata_on_non_generic_param);
@@ -4845,14 +5107,21 @@ void AttributeChecker::checkOriginalDefinedInAttrs(
   // Attrs are in the reverse order of the source order. We need to visit them
   // in source order to diagnose the later attribute.
   for (auto *Attr: Attrs) {
+    auto AtLoc = Attr->AtLoc;
+    auto Platform = Attr->getPlatform();
+    auto Domain = AvailabilityDomain::forPlatform(Platform);
+    auto ParsedVersion = Attr->getParsedMovedVersion();
+    if (!Domain.isVersionValid(ParsedVersion)) {
+      diagnose(AtLoc, diag::availability_invalid_version_number_for_domain,
+               ParsedVersion, Domain);
+    }
+
     if (!Attr->isActivePlatform(Ctx))
       continue;
 
     if (diagnoseAndRemoveAttrIfDeclIsNonPublic(Attr, /*isError=*/false))
       continue;
 
-    auto AtLoc = Attr->AtLoc;
-    auto Platform = Attr->Platform;
     if (!seenPlatforms.insert({Platform, AtLoc}).second) {
       // We've seen the platform before, emit error to the previous one which
       // comes later in the source order.
@@ -4870,7 +5139,7 @@ void AttributeChecker::checkOriginalDefinedInAttrs(
       return;
 
     auto IntroVer = D->getIntroducedOSVersion(Platform);
-    if (IntroVer.value() > Attr->MovedVersion) {
+    if (IntroVer.value() > Attr->getMovedVersion()) {
       diagnose(AtLoc,
                diag::originally_definedin_must_not_before_available_version);
       return;
@@ -4926,7 +5195,7 @@ void AttributeChecker::checkAvailableAttrs(ArrayRef<AvailableAttr *> attrs) {
     SourceLoc groupEndLoc;
     bool foundWildcard = false;
     bool hasValidSpecs = false;
-    bool allValidSpecsArePlatform = true;
+    bool wildcardRequiredInList = true;
     int groupAttrCount = 0;
     for (auto *groupedAttr = groupHead; groupedAttr != nullptr;
          groupedAttr = groupedAttr->getNextGroupedAvailableAttr()) {
@@ -4950,7 +5219,7 @@ void AttributeChecker::checkAvailableAttrs(ArrayRef<AvailableAttr *> attrs) {
           foundWildcard) {
         // Only platform availability is allowed to be written groups with more
         // than one member.
-        if (!domain.isPlatform()) {
+        if (domain.mustBeSpecifiedAlone()) {
           diagnose(loc, diag::availability_must_occur_alone, domain,
                    domain.isVersioned());
           continue;
@@ -4965,11 +5234,11 @@ void AttributeChecker::checkAvailableAttrs(ArrayRef<AvailableAttr *> attrs) {
       }
 
       hasValidSpecs = true;
-      if (!domain.isPlatform())
-        allValidSpecsArePlatform = false;
+      if (domain.mustBeSpecifiedAlone())
+        wildcardRequiredInList = false;
     }
 
-    if (!foundWildcard && hasValidSpecs && allValidSpecsArePlatform) {
+    if (!foundWildcard && hasValidSpecs && wildcardRequiredInList) {
       diagnose(groupEndLoc, diag::availability_query_wildcard_required)
           .fixItInsert(groupEndLoc, ", *");
     }
@@ -4981,8 +5250,7 @@ void AttributeChecker::checkAvailableAttrs(ArrayRef<AvailableAttr *> attrs) {
   // Compute availability constraints for the decl, relative to its parent
   // declaration or to the deployment target.
   auto availabilityContext = AvailabilityContext::forDeploymentTarget(Ctx);
-  if (auto parent =
-          AvailabilityInference::parentDeclForInferredAvailability(D)) {
+  if (auto parent = D->parentDeclForAvailability()) {
     auto parentAvailability = AvailabilityContext::forDeclSignature(parent);
     availabilityContext.constrainWithContext(parentAvailability, Ctx);
   }
@@ -5006,7 +5274,7 @@ void AttributeChecker::checkAvailableAttrs(ArrayRef<AvailableAttr *> attrs) {
 
   // If the decl is potentially unavailable relative to its parent and it's
   // not a declaration that is allowed to be potentially unavailable, diagnose.
-  if (availabilityConstraint->isPotentiallyAvailable()) {
+  if (!availabilityConstraint->isUnavailable()) {
     auto attr = availabilityConstraint->getAttr();
     if (auto diag =
             TypeChecker::diagnosticIfDeclCannotBePotentiallyUnavailable(D))
@@ -5040,23 +5308,28 @@ void AttributeChecker::checkBackDeployedAttrs(
   std::map<PlatformKind, SourceLoc> seenPlatforms;
 
   const BackDeployedAttr *ActiveAttr = nullptr;
-  if (D->getBackDeployedBeforeOSVersion(Ctx))
-    ActiveAttr = D->getAttrs().getBackDeployed(Ctx, false);
+  if (auto AttrAndRange = D->getBackDeployedAttrAndRange(Ctx))
+    ActiveAttr = AttrAndRange->first;
 
   for (auto *Attr : Attrs) {
+    auto Domain = Attr->getAvailabilityDomain();
+    if (!Domain.isVersionValid(Attr->getParsedVersion())) {
+      diagnose(Attr->getLocation(),
+               diag::availability_invalid_version_number_for_domain,
+               Attr->getParsedVersion(), Domain);
+    }
+
     // Back deployment only makes sense for public declarations.
     if (diagnoseAndRemoveAttrIfDeclIsNonPublic(Attr, /*isError=*/true))
       continue;
 
     if (isa<DestructorDecl>(D)) {
-      diagnoseAndRemoveAttr(Attr, diag::attr_invalid_on_decl_kind, Attr,
-                            D->getDescriptiveKind());
+      diagnoseAndRemoveAttr(Attr, diag::attr_invalid_on_decl_kind, Attr, D);
       continue;
     }
 
     if (VD->isObjC()) {
-      diagnoseAndRemoveAttr(Attr, diag::attr_incompatible_with_objc, Attr,
-                            D->getDescriptiveKind());
+      diagnoseAndRemoveAttr(Attr, diag::attr_incompatible_with_objc, Attr, VD);
       continue;
     }
 
@@ -5064,7 +5337,7 @@ void AttributeChecker::checkBackDeployedAttrs(
     // dispatch.
     if (D->isSyntacticallyOverridable()) {
       diagnose(Attr->getLocation(), diag::attr_incompatible_with_non_final,
-               Attr, D->getDescriptiveKind());
+               Attr, VD);
       continue;
     }
 
@@ -5073,7 +5346,7 @@ void AttributeChecker::checkBackDeployedAttrs(
     if (auto *AFD = dyn_cast<AbstractFunctionDecl>(D)) {
       if (isa<ClassDecl>(D->getDeclContext()) && AFD->needsNewVTableEntry()) {
         diagnose(Attr->getLocation(), diag::attr_incompatible_with_non_final,
-                 Attr, D->getDescriptiveKind());
+                 Attr, VD);
         continue;
       }
     }
@@ -5093,7 +5366,7 @@ void AttributeChecker::checkBackDeployedAttrs(
     }
 
     auto AtLoc = Attr->AtLoc;
-    auto Platform = Attr->Platform;
+    auto Platform = Attr->getPlatform();
 
     if (!seenPlatforms.insert({Platform, AtLoc}).second) {
       // We've seen the platform before, emit error to the previous one which
@@ -5134,9 +5407,8 @@ void AttributeChecker::checkBackDeployedAttrs(
         D->getLoc(), D->getInnermostDeclContext());
 
     // Unavailable decls cannot be back deployed.
-    auto backDeployedDomain = AvailabilityDomain::forPlatform(Attr->Platform);
-    if (availability.containsUnavailableDomain(backDeployedDomain)) {
-      auto domainForDiagnostics = backDeployedDomain;
+    if (availability.containsUnavailableDomain(Domain)) {
+      auto domainForDiagnostics = Domain;
       llvm::VersionTuple ignoredVersion;
 
       AvailabilityInference::updateBeforeAvailabilityDomainForFallback(
@@ -5155,8 +5427,7 @@ void AttributeChecker::checkBackDeployedAttrs(
           break;
         }
 
-        attrDecl =
-            AvailabilityInference::parentDeclForInferredAvailability(attrDecl);
+        attrDecl = attrDecl->parentDeclForAvailability();
       } while (attrDecl);
 
       continue;
@@ -5166,9 +5437,9 @@ void AttributeChecker::checkBackDeployedAttrs(
     // If it's not, the attribute doesn't make sense since the back deployment
     // fallback could never be executed at runtime.
     if (auto availableRangeAttrPair =
-            getSemanticAvailableRangeDeclAndAttr(VD)) {
-      auto beforeDomain = AvailabilityDomain::forPlatform(Attr->Platform);
-      auto beforeVersion = Attr->Version;
+            getSemanticAvailableRangeDeclAndAttr(VD, Domain)) {
+      auto beforeDomain = Domain;
+      auto beforeVersion = Attr->getVersion();
       auto availableAttr = availableRangeAttrPair.value().first;
       auto introVersion = availableAttr.getIntroduced().value();
       AvailabilityDomain introDomain = availableAttr.getDomain();
@@ -5178,7 +5449,7 @@ void AttributeChecker::checkBackDeployedAttrs(
       AvailabilityInference::updateIntroducedAvailabilityDomainForFallback(
           availableAttr, Ctx, introDomain, introVersion);
 
-      if (Attr->Version <= introVersion) {
+      if (beforeVersion <= introVersion) {
         diagnose(AtLoc, diag::attr_has_no_effect_decl_not_available_before,
                  Attr, VD, beforeDomain, AvailabilityRange(beforeVersion));
         diagnose(availableAttr.getParsedAttr()->AtLoc,
@@ -5218,11 +5489,6 @@ Type TypeChecker::checkReferenceOwnershipAttr(VarDecl *var, Type type,
   case ReferenceOwnershipOptionality::Allowed:
     break;
   case ReferenceOwnershipOptionality::Required:
-    if (var->isLet()) {
-      var->diagnose(diag::invalid_ownership_is_let, ownershipKind);
-      attr->setInvalid();
-    }
-
     if (!isOptional) {
       attr->setInvalid();
 
@@ -5262,13 +5528,28 @@ Type TypeChecker::checkReferenceOwnershipAttr(VarDecl *var, Type type,
   }
 
   ClassDecl *underlyingClass = underlyingType->getClassOrBoundGenericClass();
-  if (underlyingClass && underlyingClass->isIncompatibleWithWeakReferences()) {
-    Diags
-        .diagnose(attr->getLocation(),
-                  diag::invalid_ownership_incompatible_class, underlyingType,
-                  ownershipKind)
-        .fixItRemove(attr->getRange());
-    attr->setInvalid();
+  if (underlyingClass) {
+    if (underlyingClass->isIncompatibleWithWeakReferences()) {
+      Diags
+          .diagnose(attr->getLocation(),
+                    diag::invalid_ownership_incompatible_class, underlyingType,
+                    ownershipKind)
+          .fixItRemove(attr->getRange());
+      attr->setInvalid();
+    }
+    // Foreign reference types cannot be held as weak references, since the
+    // Swift runtime has no way to make the pointer null when the object is
+    // deallocated.
+    // Unowned references to foreign reference types are supported.
+    if (ownershipKind == ReferenceOwnership::Weak &&
+        underlyingClass->isForeignReferenceType()) {
+      Diags
+          .diagnose(attr->getLocation(),
+                    diag::invalid_ownership_incompatible_foreign_reference_type,
+                    underlyingType)
+          .fixItRemove(attr->getRange());
+      attr->setInvalid();
+    }
   }
 
   auto PDC = dyn_cast<ProtocolDecl>(dc);
@@ -5283,12 +5564,14 @@ Type TypeChecker::checkReferenceOwnershipAttr(VarDecl *var, Type type,
   }
 
   // Embedded Swift prohibits weak/unowned but allows unowned(unsafe).
-  if (ctx.LangOpts.hasFeature(Feature::Embedded)) {
+  if (auto behavior = shouldDiagnoseEmbeddedLimitations(
+          dc, attr->getLocation(),
+          /*wasAlwaysEmbeddedError=*/true)) {
     if (ownershipKind == ReferenceOwnership::Weak ||
         ownershipKind == ReferenceOwnership::Unowned) {
       Diags.diagnose(attr->getLocation(), diag::weak_unowned_in_embedded_swift,
-               ownershipKind);
-      attr->setInvalid();
+               ownershipKind)
+        .limitBehavior(*behavior);
     }
   }
 
@@ -5347,10 +5630,9 @@ std::optional<Diagnostic>
 TypeChecker::diagnosticIfDeclCannotBeUnavailable(const Decl *D,
                                                  SemanticAvailableAttr attr) {
   auto parentIsUnavailable = [](const Decl *D) -> bool {
-    if (auto *parent =
-            AvailabilityInference::parentDeclForInferredAvailability(D)) {
+    if (auto *parent = D->parentDeclForAvailability())
       return AvailabilityContext::forDeclSignature(parent).isUnavailable();
-    }
+
     return false;
   };
 
@@ -5539,7 +5821,7 @@ DynamicallyReplacedDeclRequest::evaluate(Evaluator &evaluator,
 ValueDecl *
 SpecializeAttrTargetDeclRequest::evaluate(Evaluator &evaluator,
                                           const ValueDecl *vd,
-                                          SpecializeAttr *attr) const {
+                                          AbstractSpecializeAttr *attr) const {
   if (auto *lazyResolver = attr->resolver) {
     auto *decl =
         lazyResolver->loadTargetFunctionDecl(attr, attr->resolverContextData);
@@ -5577,7 +5859,7 @@ static bool conformsToDifferentiable(Type type,
     return false;
   if (!tangentVectorEqualsSelf)
     return true;
-  auto tanType = conf.getTypeWitnessByName(type, ctx.Id_TangentVector);
+  auto tanType = conf.getTypeWitnessByName(ctx.Id_TangentVector);
   return type->isEqual(tanType);
 }
 
@@ -5777,6 +6059,10 @@ static DescriptiveDeclKind getAccessorDescriptiveDeclKind(AccessorKind kind) {
     return DescriptiveDeclKind::MutableAddressor;
   case AccessorKind::Init:
     return DescriptiveDeclKind::InitAccessor;
+  case AccessorKind::Borrow:
+    return DescriptiveDeclKind::BorrowAccessor;
+  case AccessorKind::Mutate:
+    return DescriptiveDeclKind::MutateAccessor;
   }
 }
 
@@ -5904,7 +6190,6 @@ static AbstractFunctionDecl *findAutoDiffOriginalFunctionDecl(
     for (auto invalidCandidatePair : invalidCandidates) {
       auto *invalidCandidate = invalidCandidatePair.first;
       auto invalidCandidateKind = invalidCandidatePair.second;
-      auto declKind = invalidCandidate->getDescriptiveKind();
       switch (invalidCandidateKind) {
       case AbstractFunctionDeclLookupErrorKind::NoCandidatesFound:
         diags.diagnose(invalidCandidate, diag::cannot_find_in_scope, funcName,
@@ -5925,28 +6210,28 @@ static AbstractFunctionDecl *findAutoDiffOriginalFunctionDecl(
         if (auto genSig = expectedOriginalFnType->getOptGenericSignature()) {
           diags.diagnose(invalidCandidate,
                          diag::autodiff_attr_original_decl_type_mismatch,
-                         declKind, expectedOriginalFnType,
+                         invalidCandidate, expectedOriginalFnType,
                          /*hasGenericSignature*/ true);
           break;
         }
         // Otherwise, emit a "candidate does not have expected type ..." error.
         diags.diagnose(invalidCandidate,
                        diag::autodiff_attr_original_decl_type_mismatch,
-                       declKind, expectedOriginalFnType,
+                       invalidCandidate, expectedOriginalFnType,
                        /*hasGenericSignature*/ false);
         break;
       }
       case AbstractFunctionDeclLookupErrorKind::CandidateWrongTypeContext:
         diags.diagnose(invalidCandidate,
                        diag::autodiff_attr_original_decl_not_same_type_context,
-                       declKind);
+                       invalidCandidate);
         break;
       case AbstractFunctionDeclLookupErrorKind::CandidateMissingAccessor: {
         auto accessorKind = maybeAccessorKind.value_or(AccessorKind::Get);
         auto accessorDeclKind = getAccessorDescriptiveDeclKind(accessorKind);
         diags.diagnose(invalidCandidate,
                        diag::autodiff_attr_original_decl_missing_accessor,
-                       declKind, accessorDeclKind);
+                       invalidCandidate, accessorDeclKind);
         break;
       }
       case AbstractFunctionDeclLookupErrorKind::CandidateProtocolRequirement:
@@ -5956,7 +6241,7 @@ static AbstractFunctionDecl *findAutoDiffOriginalFunctionDecl(
       case AbstractFunctionDeclLookupErrorKind::CandidateNotFunctionDeclaration:
         diags.diagnose(invalidCandidate,
                        diag::autodiff_attr_original_decl_invalid_kind,
-                       declKind);
+                       invalidCandidate);
         break;
       }
     }
@@ -5967,10 +6252,9 @@ static AbstractFunctionDecl *findAutoDiffOriginalFunctionDecl(
     diags.diagnose(funcNameLoc, diag::autodiff_attr_original_decl_ambiguous,
                    funcName);
     for (auto *validCandidate : validCandidates) {
-      auto declKind = validCandidate->getDescriptiveKind();
       diags.diagnose(validCandidate,
                      diag::autodiff_attr_original_decl_ambiguous_candidate,
-                     declKind);
+                     validCandidate);
     }
     return nullptr;
   }
@@ -6436,21 +6720,21 @@ typecheckDifferentiableAttrforDecl(AbstractFunctionDecl *original,
     // Dynamic `Self` is supported only as a single top-level result for class
     // members. JVP/VJP functions returning `(Self, ...)` tuples would not
     // type-check.
-    bool diagnoseDynamicSelfResult = original->hasDynamicSelfResult();
-    if (diagnoseDynamicSelfResult) {
-      // Diagnose class initializers in non-final classes.
-      if (isa<ConstructorDecl>(original)) {
-        if (!classDecl->isSemanticallyFinal()) {
-          diags.diagnose(
-              attr->getLocation(),
-              diag::differentiable_attr_nonfinal_class_init_unsupported,
-              classDecl->getDeclaredInterfaceType());
-          attr->setInvalid();
-          return nullptr;
-        }
+    // Diagnose class initializers in non-final classes.
+    if (isa<ConstructorDecl>(original)) {
+      if (!classDecl->isSemanticallyFinal()) {
+        diags.diagnose(
+            attr->getLocation(),
+            diag::differentiable_attr_nonfinal_class_init_unsupported,
+            classDecl->getDeclaredInterfaceType());
+        attr->setInvalid();
+        return nullptr;
       }
+    }
+
+    if (auto *funcDecl = dyn_cast<FuncDecl>(original)) {
       // Diagnose all other declarations returning dynamic `Self`.
-      else {
+      if (funcDecl->getResultInterfaceType()->hasDynamicSelfType()) {
         diags.diagnose(
             attr->getLocation(),
             diag::
@@ -6830,19 +7114,19 @@ static bool typeCheckDerivativeAttr(DerivativeAttr *attr) {
     // Dynamic `Self` is supported only as a single top-level result for class
     // members. JVP/VJP functions returning `(Self, ...)` tuples would not
     // type-check.
-    bool diagnoseDynamicSelfResult = originalAFD->hasDynamicSelfResult();
-    if (diagnoseDynamicSelfResult) {
+    if (isa<ConstructorDecl>(originalAFD)) {
       // Diagnose class initializers in non-final classes.
-      if (isa<ConstructorDecl>(originalAFD)) {
-        if (!classDecl->isSemanticallyFinal()) {
-          diags.diagnose(attr->getLocation(),
-                         diag::derivative_attr_nonfinal_class_init_unsupported,
-                         classDecl->getDeclaredInterfaceType());
-          return true;
-        }
+      if (!classDecl->isSemanticallyFinal()) {
+        diags.diagnose(attr->getLocation(),
+                       diag::derivative_attr_nonfinal_class_init_unsupported,
+                       classDecl->getDeclaredInterfaceType());
+        return true;
       }
+    }
+
+    if (auto *FD = dyn_cast<FuncDecl>(originalAFD)) {
       // Diagnose all other declarations returning dynamic `Self`.
-      else {
+      if (FD->getResultInterfaceType()->hasDynamicSelfType()) {
         diags.diagnose(
             attr->getLocation(),
             diag::derivative_attr_class_member_dynamic_self_result_unsupported,
@@ -6924,6 +7208,13 @@ static bool typeCheckDerivativeAttr(DerivativeAttr *attr) {
     return true;
   }
 
+  if (originalAFD->getAttrs().hasAttribute<AlwaysEmitIntoClientAttr>() !=
+      derivative->getAttrs().hasAttribute<AlwaysEmitIntoClientAttr>()) {
+    diags.diagnose(derivative->getLoc(),
+                   diag::derivative_attr_always_emit_into_client_mismatch);
+    return true;
+  }
+
   // Get the resolved differentiability parameter indices.
   auto *resolvedDiffParamIndices = attr->getParameterIndices();
 
@@ -7535,34 +7826,84 @@ void AttributeChecker::visitNonisolatedAttr(NonisolatedAttr *attr) {
   // that do not have storage.
   auto dc = D->getDeclContext();
 
+  if (attr->isNonSending()) {
+    // Just like `@concurrent` this form of `nonisolated` is only
+    // applicable to certain declarations.
+    if (!DeclAttribute::canAttributeAppearOnDecl(DeclAttrKind::Concurrent, D)) {
+      diagnoseAndRemoveAttr(
+          attr, diag::cannot_specify_execution_behavior_for_decl, attr);
+      return;
+    }
+
+    checkExecutionBehaviorAttribute(attr);
+    return;
+  }
+
   if (auto var = dyn_cast<VarDecl>(D)) {
     // stored properties have limitations as to when they can be nonisolated.
     auto type = var->getTypeInContext();
-    if (var->hasStorage()) {
+    if (var->hasStorage() || var->hasAttachedPropertyWrapper() ||
+        var->getAttrs().hasAttribute<LazyAttr>()) {
+
+      if (auto nominal = dyn_cast<NominalTypeDecl>(dc)) {
+        // 'nonisolated' can not be applied to stored properties inside
+        // distributed actors. Attempts of nonisolated access would be
+        // cross-actor, which means they might be accessing on a remote actor,
+        // in which case the stored property storage does not exist.
+        //
+        // The synthesized "id" and "actorSystem" are the only exceptions,
+        // because the implementation mirrors them.
+        if (nominal->isDistributedActor() &&
+            !(var->getName() == Ctx.Id_id ||
+              var->getName() == Ctx.Id_actorSystem)) {
+          diagnoseAndRemoveAttr(attr,
+                                diag::nonisolated_distributed_actor_storage);
+          return;
+        }
+      }
+
       {
         // A stored property can be 'nonisolated' if it is a 'Sendable' member
         // of a 'Sendable' value type.
+        // The above rule does not apply to lazy properties and properties with
+        // property wrappers, because backing storage is a stored
+        // 'var' that is part of the internal state of the actor which could
+        // only be accessed in actor's isolation context.
         bool canBeNonisolated = false;
         if (auto nominal = dc->getSelfStructDecl()) {
-          if (nominal->getDeclaredTypeInContext()->isSendableType() &&
+          if (var->hasStorage() &&
+              nominal->getDeclaredTypeInContext()->isSendableType() &&
               !var->isStatic() && type->isSendableType()) {
             canBeNonisolated = true;
           }
         }
 
-          // Additionally, a stored property of a non-'Sendable' type can be
-          // explicitly marked 'nonisolated'.
-          if (auto parentDecl = dc->getDeclaredTypeInContext())
-            if (!parentDecl->isSendableType()) {
-              canBeNonisolated = true;
-            }
+        // Additionally, a stored property of a non-'Sendable' type can be
+        // explicitly marked 'nonisolated'.
+        if (auto parentDecl = dc->getDeclaredTypeInContext())
+          if (!parentDecl->isSendableType()) {
+            canBeNonisolated = true;
+          }
 
         // Otherwise, this stored property has to be qualified as 'unsafe'.
         if (var->supportsMutation() && !attr->isUnsafe() && !canBeNonisolated) {
-          diagnoseAndRemoveAttr(attr, diag::nonisolated_mutable_storage)
+          if (var->hasAttachedPropertyWrapper()) {
+            diagnoseAndRemoveAttr(attr, diag::nonisolated_mutable_storage)
+              .warnUntilSwiftVersionIf(attr->isImplicit(), 6)
               .fixItInsertAfter(attr->getRange().End, "(unsafe)");
-          var->diagnose(diag::nonisolated_mutable_storage_note, var);
-          return;
+            return;
+          } else if (var->getAttrs().hasAttribute<LazyAttr>()) {
+            diagnoseAndRemoveAttr(attr, diag::nonisolated_mutable_storage)
+              .warnUntilSwiftVersion(6)
+              .fixItInsertAfter(attr->getRange().End, "(unsafe)");
+            return;
+          } else {
+            diagnoseAndRemoveAttr(attr, diag::nonisolated_mutable_storage)
+              .fixItInsertAfter(attr->getRange().End, "(unsafe)");
+            if (var->hasStorage())
+              var->diagnose(diag::nonisolated_mutable_storage_note, var);
+            return;
+          }
         }
 
         // 'nonisolated' without '(unsafe)' is not allowed on non-Sendable
@@ -7576,23 +7917,6 @@ void AttributeChecker::visitNonisolatedAttr(NonisolatedAttr *attr) {
         }
       }
 
-      if (auto nominal = dyn_cast<NominalTypeDecl>(dc)) {
-        // 'nonisolated' can not be applied to stored properties inside
-        // distributed actors. Attempts of nonisolated access would be
-        // cross-actor, which means they might be accessing on a remote actor,
-        // in which case the stored property storage does not exist.
-        //
-        // The synthesized "id" and "actorSystem" are the only exceptions,
-        // because the implementation mirrors them.
-        if (nominal->isDistributedActor() &&
-            !(var->getName() == Ctx.Id_id ||
-              var->getName() == Ctx.Id_actorSystem)) {
-          diagnoseAndRemoveAttr(attr,
-                                diag::nonisolated_distributed_actor_storage);
-          return;
-        }
-      }
-
       // 'nonisolated(unsafe)' is redundant for 'Sendable' immutables.
       if (attr->isUnsafe() &&
           type->isSendableType() &&
@@ -7628,22 +7952,6 @@ void AttributeChecker::visitNonisolatedAttr(NonisolatedAttr *attr) {
       }
     }
 
-    // Using 'nonisolated' with lazy properties and wrapped properties is
-    // unsupported, because backing storage is a stored 'var' that is part
-    // of the internal state of the actor which could only be accessed in
-    // actor's isolation context.
-    if (var->hasAttachedPropertyWrapper()) {
-      diagnoseAndRemoveAttr(attr, diag::nonisolated_wrapped_property)
-        .warnUntilSwiftVersionIf(attr->isImplicit(), 6);
-      return;
-    }
-
-    if (var->getAttrs().hasAttribute<LazyAttr>()) {
-      diagnose(attr->getLocation(), diag::nonisolated_lazy)
-        .warnUntilSwiftVersion(6);
-      return;
-    }
-
     // nonisolated can not be applied to local properties unless qualified as
     // 'unsafe'.
     if (dc->isLocalContext() && !attr->isUnsafe()) {
@@ -7674,17 +7982,15 @@ void AttributeChecker::visitNonisolatedAttr(NonisolatedAttr *attr) {
     }
   }
 
-  diagnoseIsolatedDeinitInValueTypes(attr);
-
   if (auto VD = dyn_cast<ValueDecl>(D)) {
     //'nonisolated(unsafe)' is meaningless for computed properties, functions etc.
     auto var = dyn_cast<VarDecl>(VD);
     if (attr->isUnsafe() &&
         (!var || !var->hasStorage())) {
       auto &ctx = VD->getASTContext();
-      ctx.Diags.diagnose(attr->getStartLoc(),
-                         diag::nonisolated_unsafe_uneffective_on_funcs,
-                         VD->getDescriptiveKind(), VD)
+      ctx.Diags
+          .diagnose(attr->getStartLoc(),
+                    diag::nonisolated_unsafe_uneffective_on_funcs, VD)
           .fixItReplace(attr->getStartLoc(), "nonisolated");
     }
 
@@ -7693,7 +7999,7 @@ void AttributeChecker::visitNonisolatedAttr(NonisolatedAttr *attr) {
 }
 
 void AttributeChecker::visitIsolatedAttr(IsolatedAttr *attr) {
-  diagnoseIsolatedDeinitInValueTypes(attr);
+  checkIsolatedDeinitAttr(attr);
 }
 
 void AttributeChecker::visitGlobalActorAttr(GlobalActorAttr *attr) {
@@ -7710,8 +8016,6 @@ void AttributeChecker::visitGlobalActorAttr(GlobalActorAttr *attr) {
     return;
   }
 
-  diagnoseIsolatedDeinitInValueTypes(attr);
-
   (void)nominal->isGlobalActor();
 }
 
@@ -7768,6 +8072,40 @@ void AttributeChecker::visitAsyncAttr(AsyncAttr *attr) {
   }
 }
 
+void AttributeChecker::visitInheritActorContextAttr(
+    InheritActorContextAttr *attr) {
+  auto *P = dyn_cast<ParamDecl>(D);
+  if (!P)
+    return;
+
+  auto paramTy = P->getInterfaceType();
+  auto *funcTy =
+      paramTy->lookThroughAllOptionalTypes()->getAs<AnyFunctionType>();
+  if (!funcTy) {
+    diagnoseAndRemoveAttr(attr, diag::inherit_actor_context_only_on_func_types,
+                          attr, paramTy);
+    return;
+  }
+
+  // The type has to be either `@Sendable` or `sending` _and_
+  // `async` or `@isolated(any)`.
+  if (!(funcTy->isSendable() || P->isSending())) {
+    diagnose(attr->getLocation(),
+             diag::inherit_actor_context_only_on_sending_or_Sendable_params,
+             attr)
+        .warnUntilFutureSwiftVersion();
+  }
+
+  // Either `async` or `@isolated(any)`.
+  if (!(funcTy->isAsync() || funcTy->getIsolation().isErased())) {
+    diagnoseAndRemoveAttr(
+        attr,
+        diag::inherit_actor_context_only_on_async_or_isolation_erased_params,
+        attr)
+        .warnUntilFutureSwiftVersion();
+  }
+}
+
 void AttributeChecker::visitMarkerAttr(MarkerAttr *attr) {
   auto proto = dyn_cast<ProtocolDecl>(D);
   if (!proto)
@@ -7830,8 +8168,7 @@ void AttributeChecker::visitUnavailableFromAsyncAttr(
             vd);
       } else {
         D->getASTContext().Diags.diagnose(
-            D->getLoc(), diag::async_decl_must_be_available_from_async,
-            D->getDescriptiveKind());
+            D->getLoc(), diag::async_decl_must_be_available_from_async, D);
       }
     }
   }
@@ -8087,6 +8424,13 @@ void AttributeChecker::visitStaticExclusiveOnlyAttr(
   }
 }
 
+void AttributeChecker::visitManualOwnershipAttr(ManualOwnershipAttr *attr) {
+  if (Ctx.LangOpts.hasFeature(Feature::ManualOwnership))
+    return;
+
+  diagnoseAndRemoveAttr(attr, diag::attr_manual_ownership_experimental);
+}
+
 void AttributeChecker::visitWeakLinkedAttr(WeakLinkedAttr *attr) {
   if (!Ctx.LangOpts.Target.isOSBinFormatCOFF())
     return;
@@ -8095,7 +8439,28 @@ void AttributeChecker::visitWeakLinkedAttr(WeakLinkedAttr *attr) {
                         Ctx.LangOpts.Target.str());
 }
 
-void AttributeChecker::visitLifetimeAttr(LifetimeAttr *attr) {}
+void AttributeChecker::visitLifetimeAttr(LifetimeAttr *attr) {
+  if (!attr->isUnderscored()) {
+    // Allow @lifetime only in the stdlib, cxx and backward compatibility
+    // modules under -enable-experimental-feature LifetimeDependence
+    if (!Ctx.MainModule->isStdlibModule() && !Ctx.MainModule->isCxxModule() &&
+        Ctx.MainModule->getABIName() != Ctx.StdlibModuleName) {
+      Ctx.Diags.diagnose(attr->getLocation(), diag::use_lifetime_underscored);
+    }
+    if (!Ctx.LangOpts.hasFeature(Feature::LifetimeDependence)) {
+      diagnose(attr->getLocation(), diag::requires_experimental_feature,
+               "@lifetime", false, Feature::LifetimeDependence.getName());
+    }
+  } else {
+    // Allow @_lifetime under -enable-experimental-feature Lifetimes
+    if (!Ctx.LangOpts.hasFeature(Feature::Lifetimes) &&
+        !Ctx.SourceMgr.isImportMacroGeneratedLoc(attr->getLocation())) {
+      diagnose(attr->getLocation(), diag::requires_experimental_feature,
+               "@_lifetime",
+               false, Feature::Lifetimes.getName());
+    }
+  }
+}
 
 void AttributeChecker::visitAddressableSelfAttr(AddressableSelfAttr *attr) {
   if (!Ctx.LangOpts.hasFeature(Feature::AddressableParameters)) {
@@ -8128,6 +8493,18 @@ void AttributeChecker::visitUnsafeAttr(UnsafeAttr *attr) {
   }
 }
 
+void AttributeChecker::visitUnsafeSelfDependentResultAttr(
+    UnsafeSelfDependentResultAttr *attr) {
+  // TODO: Introduce a new experimental feature and check for presence
+  auto *accessor = dyn_cast<AccessorDecl>(D);
+  if (accessor &&
+      (accessor->isBorrowAccessor() || accessor->isMutateAccessor())) {
+    return;
+  }
+  Ctx.Diags.diagnose(attr->getLocation(),
+                     diag::unsafe_self_dependent_result_attr_on_invalid_decl);
+}
+
 namespace {
 
 class ClosureAttributeChecker
@@ -8150,28 +8527,13 @@ class ClosureAttributeChecker
     // Nothing else to check.
   }
 
-  void visitExecutionAttr(ExecutionAttr *attr) {
-    if (!ctx.LangOpts.hasFeature(Feature::ExecutionAttribute)) {
-      visitDeclAttribute(attr);
-      return;
-    }
-
-    // `@execution(...)` implies `async`.
-    if (closure->hasExplicitResultType() &&
-        closure->getAsyncLoc().isInvalid()) {
-      ctx.Diags
-          .diagnose(attr->getLocation(),
-                    diag::attr_execution_only_on_async_closure)
-          .fixItRemove(attr->getRangeWithAt());
-      attr->setInvalid();
-    }
-
+  void checkExecutionBehaviorAttribute(DeclAttribute *attr) {
     if (auto actorType = getExplicitGlobalActor(closure)) {
       ctx.Diags
           .diagnose(
               attr->getLocation(),
-              diag::attr_execution_type_attr_incompatible_with_global_isolation,
-              actorType)
+              diag::execution_behavior_attr_incompatible_with_global_isolation,
+              attr, actorType)
           .fixItRemove(attr->getRangeWithAt());
       attr->setInvalid();
     }
@@ -8181,13 +8543,18 @@ class ClosureAttributeChecker
         ctx.Diags
             .diagnose(
                 attr->getLocation(),
-                diag::attr_execution_type_attr_incompatible_with_isolated_param)
+                diag::execution_behavior_attr_incompatible_with_isolated_param,
+                attr)
             .fixItRemove(attr->getRangeWithAt());
         attr->setInvalid();
       }
     }
   }
 
+  void visitConcurrentAttr(ConcurrentAttr *attr) {
+    checkExecutionBehaviorAttribute(attr);
+  }
+
   void visitNonisolatedAttr(NonisolatedAttr *attr) {
     if (attr->isUnsafe() ||
         !ctx.LangOpts.hasFeature(Feature::ClosureIsolation)) {
@@ -8312,9 +8679,10 @@ ValueDecl *RenamedDeclRequest::evaluate(Evaluator &evaluator,
   if (attr->Rename.empty())
     return nullptr;
 
+  auto &ctx = attached->getASTContext();
   auto attachedContext = attached->getDeclContext();
   auto parsedName = parseDeclName(attr->Rename);
-  auto nameRef = parsedName.formDeclNameRef(attached->getASTContext());
+  auto nameRef = parsedName.formDeclNameRef(ctx);
 
   // Handle types separately
   if (isa<NominalTypeDecl>(attached)) {
@@ -8323,7 +8691,7 @@ ValueDecl *RenamedDeclRequest::evaluate(Evaluator &evaluator,
 
     SmallVector<ValueDecl *, 1> lookupResults;
     attachedContext->lookupQualified(attachedContext->getParentModule(),
-                                     nameRef.withoutArgumentLabels(),
+                                     nameRef.withoutArgumentLabels(ctx),
                                      attr->getLocation(), NL_OnlyTypes,
                                      lookupResults);
     if (lookupResults.size() == 1)
@@ -8465,7 +8833,7 @@ ArrayRef<VarDecl *> InitAccessorReferencedVariablesRequest::evaluate(
 
       ctx.Diags.diagnose(attr->getLocation(),
                          diag::init_accessor_can_refer_only_to_properties,
-                         member->getDescriptiveKind(), member->createNameRef());
+                         member);
       failed = true;
       break;
     }
diff --git a/lib/Sema/TypeCheckAttrABI.cpp b/lib/Sema/TypeCheckAttrABI.cpp
index d81c018ed7faa..9f6cb40b5b735 100644
--- a/lib/Sema/TypeCheckAttrABI.cpp
+++ b/lib/Sema/TypeCheckAttrABI.cpp
@@ -259,8 +259,7 @@ class ABIDeclChecker : public ASTComparisonVisitor<ABIDeclChecker> {
     if (api->getKind() != abi->getKind()) {
       // FIXME: DescriptiveDeclKind is overly specific; we really just want to
       //        say that e.g. a `func` can't have the ABI of a `var`.
-      diagnoseAndRemoveAttr(abiAttr, diag::attr_abi_mismatched_kind,
-                            api, abi->getDescriptiveKind());
+      diagnoseAndRemoveAttr(abiAttr, diag::attr_abi_mismatched_kind, api, abi);
       return;
     }
 
@@ -684,6 +683,7 @@ class ABIDeclChecker : public ASTComparisonVisitor<ABIDeclChecker> {
   UNSUPPORTED_DECL(PrefixOperator)
   UNSUPPORTED_DECL(PostfixOperator)
   UNSUPPORTED_DECL(MacroExpansion)
+  UNSUPPORTED_DECL(Using)
 
   bool visitAbstractFunctionDecl(AbstractFunctionDecl *api,
                                  AbstractFunctionDecl *abi) {
@@ -881,26 +881,6 @@ class ABIDeclChecker : public ASTComparisonVisitor<ABIDeclChecker> {
 
       return false;
 
-    case DeclAttribute::InferredInABIAttr:
-      if (!abi && api->canClone()) {
-        // Infer an identical attribute.
-        abi = api->clone(ctx);
-        abi->setImplicit(true);
-        abiDecl->getAttrs().add(abi);
-
-        if (ctx.LangOpts.EnableABIInferenceRemarks) {
-          SmallString<64> scratch;
-          auto abiAttrAsString = printAttr(abi, abiDecl, scratch);
-
-          abiDecl->diagnose(diag::abi_attr_inferred_attribute,
-                            abiAttrAsString, api->isDeclModifier());
-          noteAttrHere(api, apiDecl, /*isMatch=*/true);
-        }
-      }
-
-      // Other than the cloning behavior, Inferred behaves like Equivalent.
-      LLVM_FALLTHROUGH;
-
     case DeclAttribute::EquivalentInABIAttr:
       // Diagnose if API doesn't have attribute.
       if (!api) {
@@ -1123,57 +1103,33 @@ class ABIDeclChecker : public ASTComparisonVisitor<ABIDeclChecker> {
 };
 
 void checkABIAttrPBD(PatternBindingDecl *APBD, VarDecl *VD) {
-  auto &diags = VD->getASTContext().Diags;
   auto PBD = VD->getParentPatternBinding();
 
-  // To make sure we only diagnose this stuff once, check that VD is the first
-  // anchoring variable in the PBD.
-  bool isFirstAnchor = false;
+  Decl *anchorVD = nullptr;
   for (auto i : range(PBD->getNumPatternEntries())) {
-    auto anchorVD = PBD->getAnchoringVarDecl(i);
-    if (anchorVD) {
-      isFirstAnchor = (anchorVD == VD);
+    anchorVD = PBD->getAnchoringVarDecl(i);
+    if (anchorVD)
       break;
-    }
   }
 
-  if (!isFirstAnchor)
+  // To make sure we only diagnose this stuff once, check that VD is the
+  // first anchoring variable in the PBD.
+  if (anchorVD != VD)
     return;
 
-  // Check that the PBDs have the same number of patterns.
-  if (PBD->getNumPatternEntries() < APBD->getNumPatternEntries()) {
-    diags.diagnose(APBD->getPattern(PBD->getNumPatternEntries())->getLoc(),
-                   diag::attr_abi_mismatched_pbd_size, /*abiHasExtra=*/false);
-    return;
-  }
-  if (PBD->getNumPatternEntries() > APBD->getNumPatternEntries()) {
-    diags.diagnose(PBD->getPattern(APBD->getNumPatternEntries())->getLoc(),
-                   diag::attr_abi_mismatched_pbd_size, /*abiHasExtra=*/true);
+  // In the final approved feature, we only permit single-variable patterns.
+  // (However, the rest of the compiler tolerates them.)
+  if (!PBD->getSingleVar() || !APBD->getSingleVar()) {
+    PBD->diagnose(diag::attr_abi_multiple_vars,
+                  anchorVD ? anchorVD->getDescriptiveKind()
+                           : PBD->getDescriptiveKind());
     return;
   }
 
-  // Check that each pattern has the same number of variables.
-  for (auto i : range(PBD->getNumPatternEntries())) {
-    SmallVector<VarDecl *, 8> VDs;
-    SmallVector<VarDecl *, 8> AVDs;
-
-    PBD->getPattern(i)->collectVariables(VDs);
-    APBD->getPattern(i)->collectVariables(AVDs);
-
-    if (VDs.size() < AVDs.size()) {
-      for (auto AVD : drop_begin(AVDs, VDs.size())) {
-        AVD->diagnose(diag::attr_abi_mismatched_var,
-                      AVD, /*isABI=*/true);
-      }
-    }
-    else if (VDs.size() > AVDs.size()) {
-      for (auto VD : drop_begin(VDs, AVDs.size())) {
-        VD->diagnose(diag::attr_abi_mismatched_var,
-                     VD, /*isABI=*/false);
-      }
-    }
-  }
+  // Check the ABI PBD--this is what checks the underlying vars.
+  TypeChecker::typeCheckDecl(APBD);
 }
+
 } // end anonymous namespace
 
 void TypeChecker::checkDeclABIAttribute(Decl *D, ABIAttr *attr) {
diff --git a/lib/Sema/TypeCheckAvailability.cpp b/lib/Sema/TypeCheckAvailability.cpp
index 0bb8013563a59..9befa1030cf0d 100644
--- a/lib/Sema/TypeCheckAvailability.cpp
+++ b/lib/Sema/TypeCheckAvailability.cpp
@@ -24,12 +24,12 @@
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/AvailabilityConstraint.h"
 #include "swift/AST/AvailabilityDomain.h"
-#include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/AvailabilityScope.h"
 #include "swift/AST/AvailabilitySpec.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/DeclExportabilityVisitor.h"
 #include "swift/AST/DiagnosticsParse.h"
+#include "swift/AST/ExistentialLayout.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/Initializer.h"
 #include "swift/AST/NameLookup.h"
@@ -241,20 +241,6 @@ ExportContext::getExportabilityReason() const {
   return std::nullopt;
 }
 
-/// Returns true if there is any availability attribute on the declaration
-/// that is active.
-// FIXME: [availability] De-duplicate this with AvailabilityScopeBuilder.cpp.
-static bool hasActiveAvailableAttribute(const Decl *D, ASTContext &ctx) {
-  D = D->getAbstractSyntaxDeclForAttributes();
-
-  for (auto Attr : D->getSemanticAvailableAttrs()) {
-    if (Attr.isActive(ctx))
-      return true;
-  }
-
-  return false;
-}
-
 static bool shouldAllowReferenceToUnavailableInSwiftDeclaration(
     const Decl *D, const ExportContext &where) {
   auto *DC = where.getDeclContext();
@@ -276,16 +262,18 @@ static bool shouldAllowReferenceToUnavailableInSwiftDeclaration(
   return false;
 }
 
-// Utility function to help determine if noasync diagnostics are still
-// appropriate even if a `DeclContext` returns `false` from `isAsyncContext()`.
-static bool shouldTreatDeclContextAsAsyncForDiagnostics(const DeclContext *DC) {
-  if (auto *D = DC->getAsDecl())
-    if (auto *FD = dyn_cast<FuncDecl>(D))
+/// Retrieve the innermost DeclContext that should be consulted for noasync
+/// checking.
+static const DeclContext *
+getInnermostDeclContextForNoAsync(const DeclContext *DC) {
+  if (auto *D = DC->getAsDecl()) {
+    if (auto *FD = dyn_cast<FuncDecl>(D)) {
       if (FD->isDeferBody())
         // If this is a defer body, we should delegate to its parent.
-        return shouldTreatDeclContextAsAsyncForDiagnostics(DC->getParent());
-
-  return DC->isAsyncContext();
+        return getInnermostDeclContextForNoAsync(DC->getParent());
+    }
+  }
+  return DC;
 }
 
 /// A class that walks the AST to find the innermost (i.e., deepest) node that
@@ -637,15 +625,18 @@ static void fixAvailabilityForDecl(
     const AvailabilityRange &RequiredAvailability, ASTContext &Context) {
   assert(D);
 
-  // Don't suggest adding an @available() to a declaration where we would
+  // Don't suggest adding an @available to a declaration where we would
   // emit a diagnostic saying it is not allowed.
   if (TypeChecker::diagnosticIfDeclCannotBePotentiallyUnavailable(D).has_value())
     return;
 
-  if (hasActiveAvailableAttribute(D, Context)) {
-    // For QoI, in future should emit a fixit to update the existing attribute.
+  // Don't suggest adding an @available attribute to a declaration that already
+  // has one that is active for the given domain.
+  // FIXME: Emit a fix-it to adjust the existing attribute instead.
+  if (D->hasAnyMatchingActiveAvailableAttr([&](SemanticAvailableAttr attr) {
+        return attr.getDomain().isRelated(Domain);
+      }))
     return;
-  }
 
   // For some declarations (variables, enum elements), the location in concrete
   // syntax to suggest the Fix-It may differ from the declaration to which
@@ -655,9 +646,9 @@ static void fixAvailabilityForDecl(
 
   // To avoid exposing the pattern binding declaration to the user, get the
   // descriptive kind from one of the VarDecls.
-  DescriptiveDeclKind KindForDiagnostic = ConcDecl->getDescriptiveKind();
-  if (KindForDiagnostic == DescriptiveDeclKind::PatternBinding) {
-    KindForDiagnostic = D->getDescriptiveKind();
+  const auto *DeclForDiagnostic = ConcDecl;
+  if (isa<PatternBindingDecl>(DeclForDiagnostic)) {
+    DeclForDiagnostic = D;
   }
 
   SourceLoc InsertLoc =
@@ -668,10 +659,18 @@ static void fixAvailabilityForDecl(
   StringRef OriginalIndent =
       Lexer::getIndentationForLine(Context.SourceMgr, InsertLoc);
 
-  D->diagnose(diag::availability_add_attribute, KindForDiagnostic)
-      .fixItInsert(InsertLoc, diag::insert_available_attr,
-                   Domain.getNameForAttributePrinting(),
-                   RequiredAvailability.getVersionString(), OriginalIndent);
+  llvm::SmallString<64> FixItBuffer;
+  llvm::raw_svector_ostream FixIt(FixItBuffer);
+
+  FixIt << "@available(" << Domain.getNameForAttributePrinting();
+  if (Domain.isVersioned())
+    FixIt << " " <<  RequiredAvailability.getVersionString();
+  if (Domain.isPlatform())
+    FixIt << ", *";
+  FixIt << ")\n" << OriginalIndent;
+
+  D->diagnose(diag::availability_add_attribute, DeclForDiagnostic)
+      .fixItInsert(InsertLoc, FixIt.str());
 }
 
 /// In the special case of being in an existing, nontrivial availability scope
@@ -693,8 +692,8 @@ static bool fixAvailabilityByNarrowingNearbyVersionCheck(
   if (!scope)
     return false;
 
-  // FIXME: [availability] Support fixing availability for versionless domains.
-  auto ExplicitAvailability = scope->getExplicitAvailabilityRange();
+  auto ExplicitAvailability =
+      scope->getExplicitAvailabilityRange(Domain, Context);
   if (ExplicitAvailability && !RequiredAvailability.isAlwaysAvailable() &&
       scope->getReason() != AvailabilityScope::Reason::Root &&
       RequiredAvailability.isContainedIn(*ExplicitAvailability)) {
@@ -730,8 +729,9 @@ static bool fixAvailabilityByNarrowingNearbyVersionCheck(
 /// Emit a diagnostic note and Fix-It to add an if #available(...) { } guard
 /// that checks for the given version range around the given node.
 static void fixAvailabilityByAddingVersionCheck(
-    ASTNode NodeToWrap, const AvailabilityRange &RequiredAvailability,
-    SourceRange ReferenceRange, ASTContext &Context) {
+    ASTNode NodeToWrap, AvailabilityDomain Domain,
+    const AvailabilityRange &RequiredAvailability, SourceRange ReferenceRange,
+    ASTContext &Context) {
   // If this is an implicit variable that wraps an expression,
   // let's point to it's initializer. For example, result builder
   // transform captures expressions into implicit variables.
@@ -776,24 +776,32 @@ static void fixAvailabilityByAddingVersionCheck(
       StartAt += NewLine.length();
     }
 
-    PlatformKind Target = targetPlatform(Context.LangOpts);
+    AvailabilityDomain QueryDomain = Domain;
 
     // Runtime availability checks that specify app extension platforms don't
     // work, so only suggest checks against the base platform.
-    if (auto TargetRemovingAppExtension =
-            basePlatformForExtensionPlatform(Target))
-      Target = *TargetRemovingAppExtension;
+    if (auto CanonicalPlatform =
+            basePlatformForExtensionPlatform(QueryDomain.getPlatformKind())) {
+      QueryDomain = AvailabilityDomain::forPlatform(*CanonicalPlatform);
+    }
+
+    Out << "if #available(" << QueryDomain.getNameForAttributePrinting();
+    if (QueryDomain.isVersioned())
+      Out << " " << RequiredAvailability.getVersionString();
+    if (QueryDomain.isPlatform())
+      Out << ", *";
 
-    Out << "if #available(" << platformString(Target) << " "
-        << RequiredAvailability.getVersionString() << ", *) {\n";
+    Out << ") {\n";
 
     Out << OriginalIndent << ExtraIndent << GuardedText << "\n";
 
     // We emit an empty fallback case with a comment to encourage the developer
     // to think explicitly about whether fallback on earlier versions is needed.
     Out << OriginalIndent << "} else {\n";
-    Out << OriginalIndent << ExtraIndent << "// Fallback on earlier versions\n";
-    Out << OriginalIndent << "}";
+    Out << OriginalIndent << ExtraIndent << "// Fallback";
+    if (QueryDomain.isVersioned())
+      Out << " on earlier versions";
+    Out << "\n" << OriginalIndent << "}";
   }
 
   Context.Diags.diagnose(
@@ -811,10 +819,6 @@ static void fixAvailability(SourceRange ReferenceRange,
   if (ReferenceRange.isInvalid())
     return;
 
-  // FIXME: [availability] Support non-platform domains.
-  if (!Domain.isPlatform())
-    return;
-
   std::optional<ASTNode> NodeToWrapInVersionCheck;
   const Decl *FoundMemberDecl = nullptr;
   const Decl *FoundTypeLevelDecl = nullptr;
@@ -826,8 +830,8 @@ static void fixAvailability(SourceRange ReferenceRange,
   // Suggest wrapping in if #available(...) { ... } if possible.
   if (NodeToWrapInVersionCheck.has_value()) {
     fixAvailabilityByAddingVersionCheck(NodeToWrapInVersionCheck.value(),
-                                        RequiredAvailability, ReferenceRange,
-                                        Context);
+                                        Domain, RequiredAvailability,
+                                        ReferenceRange, Context);
   }
 
   // Suggest adding availability attributes.
@@ -1499,9 +1503,12 @@ static void diagnoseIfDeprecated(SourceRange ReferenceRange,
   // We match the behavior of clang to not report deprecation warnings
   // inside declarations that are themselves deprecated on all deployment
   // targets.
-  if (Availability.isDeprecated()) {
+  if (Availability.isDeprecated())
+    return;
+
+  // Skip diagnosing deprecated types in unavailable contexts.
+  if (Availability.isUnavailable() && isa<TypeDecl>(DeprecatedDecl))
     return;
-  }
 
   auto *ReferenceDC = Where.getDeclContext();
   auto &Context = ReferenceDC->getASTContext();
@@ -1627,8 +1634,8 @@ void swift::diagnoseOverrideOfUnavailableDecl(ValueDecl *override,
   auto &diags = ctx.Diags;
   if (attr.getRename().empty()) {
     EncodedDiagnosticMessage EncodedMessage(attr.getMessage());
-    diags.diagnose(override, diag::override_unavailable,
-                   override->getBaseName(), EncodedMessage.Message);
+    diags.diagnose(override, diag::cannot_override_unavailable,
+                   override, EncodedMessage.Message);
 
     diags.diagnose(base, diag::availability_marked_unavailable, base);
     return;
@@ -1692,15 +1699,16 @@ bool shouldHideDomainNameForConstraintDiagnostic(
   case AvailabilityDomain::Kind::Custom:
   case AvailabilityDomain::Kind::PackageDescription:
     return true;
+  case AvailabilityDomain::Kind::SwiftRuntime:
   case AvailabilityDomain::Kind::Platform:
     return false;
-  case AvailabilityDomain::Kind::SwiftLanguage:
+  case AvailabilityDomain::Kind::SwiftLanguageMode:
     switch (constraint.getReason()) {
-    case AvailabilityConstraint::Reason::UnconditionallyUnavailable:
-    case AvailabilityConstraint::Reason::UnavailableForDeployment:
+    case AvailabilityConstraint::Reason::UnavailableUnconditionally:
+    case AvailabilityConstraint::Reason::UnavailableUnintroduced:
       return false;
-    case AvailabilityConstraint::Reason::PotentiallyUnavailable:
-    case AvailabilityConstraint::Reason::Obsoleted:
+    case AvailabilityConstraint::Reason::Unintroduced:
+    case AvailabilityConstraint::Reason::UnavailableObsolete:
       return true;
     }
   }
@@ -1725,7 +1733,7 @@ bool diagnoseExplicitUnavailability(SourceLoc loc,
 
   auto type = rootConf->getType();
   auto proto = rootConf->getProtocol()->getDeclaredInterfaceType();
-  auto domain = constraint.getDomain();
+  auto domainAndRange = constraint.getDomainAndRange(ctx);
   auto attr = constraint.getAttr();
 
   // Downgrade unavailable Sendable conformance diagnostics where
@@ -1736,29 +1744,30 @@ bool diagnoseExplicitUnavailability(SourceLoc loc,
   EncodedDiagnosticMessage EncodedMessage(attr.getMessage());
   diags
       .diagnose(loc, diag::conformance_availability_unavailable, type, proto,
-                shouldHideDomainNameForConstraintDiagnostic(constraint), domain,
-                EncodedMessage.Message)
+                shouldHideDomainNameForConstraintDiagnostic(constraint),
+                domainAndRange.getDomain(), EncodedMessage.Message)
       .limitBehaviorWithPreconcurrency(behavior, preconcurrency)
       .warnUntilSwiftVersionIf(warnIfConformanceUnavailablePreSwift6, 6);
 
   switch (constraint.getReason()) {
-  case AvailabilityConstraint::Reason::UnconditionallyUnavailable:
+  case AvailabilityConstraint::Reason::UnavailableUnconditionally:
     diags
         .diagnose(ext, diag::conformance_availability_marked_unavailable, type,
                   proto)
         .highlight(attr.getParsedAttr()->getRange());
     break;
-  case AvailabilityConstraint::Reason::UnavailableForDeployment:
+  case AvailabilityConstraint::Reason::UnavailableUnintroduced:
     diags.diagnose(ext, diag::conformance_availability_introduced_in_version,
-                   type, proto, domain, attr.getIntroducedRange(ctx).value());
+                   type, proto, domainAndRange.getDomain(),
+                   domainAndRange.getRange());
     break;
-  case AvailabilityConstraint::Reason::Obsoleted:
+  case AvailabilityConstraint::Reason::UnavailableObsolete:
     diags
         .diagnose(ext, diag::conformance_availability_obsoleted, type, proto,
-                  domain, attr.getObsoletedRange(ctx).value())
+                  domainAndRange.getDomain(), domainAndRange.getRange())
         .highlight(attr.getParsedAttr()->getRange());
     break;
-  case AvailabilityConstraint::Reason::PotentiallyUnavailable:
+  case AvailabilityConstraint::Reason::Unintroduced:
     llvm_unreachable("unexpected constraint");
   }
   return true;
@@ -1768,8 +1777,17 @@ std::optional<AvailabilityConstraint>
 swift::getUnsatisfiedAvailabilityConstraint(const Decl *decl,
                                             const DeclContext *referenceDC,
                                             SourceLoc referenceLoc) {
+  AvailabilityConstraintFlags flags;
+
+  // In implicit code, allow references to universally unavailable declarations
+  // as long as the context is also universally unavailable.
+  if (referenceLoc.isInvalid())
+    flags |= AvailabilityConstraintFlag::
+        AllowUniversallyUnavailableInCompatibleContexts;
+
   return getAvailabilityConstraintsForDecl(
-             decl, AvailabilityContext::forLocation(referenceLoc, referenceDC))
+             decl, AvailabilityContext::forLocation(referenceLoc, referenceDC),
+             flags)
       .getPrimaryConstraint();
 }
 
@@ -2105,7 +2123,7 @@ bool diagnoseExplicitUnavailability(
     return false;
 
   auto Attr = constraint.getAttr();
-  if (Attr.getDomain().isSwiftLanguage() && !Attr.isVersionSpecific()) {
+  if (Attr.getDomain().isSwiftLanguageMode() && !Attr.isVersionSpecific()) {
     if (shouldAllowReferenceToUnavailableInSwiftDeclaration(D, Where))
       return false;
   }
@@ -2113,7 +2131,7 @@ bool diagnoseExplicitUnavailability(
   SourceLoc Loc = R.Start;
   ASTContext &ctx = D->getASTContext();
   auto &diags = ctx.Diags;
-  auto domain = constraint.getDomain();
+  auto domainAndRange = constraint.getDomainAndRange(ctx);
 
   // TODO: Consider removing this.
   // ObjC keypaths components weren't checked previously, so errors are demoted
@@ -2149,37 +2167,34 @@ bool diagnoseExplicitUnavailability(
     // Skip the note emitted below.
     return true;
   } else {
-    auto unavailableDiagnosticDomain = domain;
-    AvailabilityInference::updateAvailabilityDomainForFallback(
-        Attr, ctx, unavailableDiagnosticDomain);
     EncodedDiagnosticMessage EncodedMessage(message);
     diags
         .diagnose(Loc, diag::availability_decl_unavailable, D,
                   shouldHideDomainNameForConstraintDiagnostic(constraint),
-                  unavailableDiagnosticDomain, EncodedMessage.Message)
+                  domainAndRange.getDomain(), EncodedMessage.Message)
         .highlight(R)
         .limitBehavior(limit);
   }
 
   auto sourceRange = Attr.getParsedAttr()->getRange();
   switch (constraint.getReason()) {
-  case AvailabilityConstraint::Reason::UnconditionallyUnavailable:
+  case AvailabilityConstraint::Reason::UnavailableUnconditionally:
     diags.diagnose(D, diag::availability_marked_unavailable, D)
         .highlight(sourceRange);
     break;
-  case AvailabilityConstraint::Reason::UnavailableForDeployment:
+  case AvailabilityConstraint::Reason::UnavailableUnintroduced:
     diags
-        .diagnose(D, diag::availability_introduced_in_version, D, domain,
-                  Attr.getIntroducedRange(ctx).value())
+        .diagnose(D, diag::availability_introduced_in_version, D,
+                  domainAndRange.getDomain(), domainAndRange.getRange())
         .highlight(sourceRange);
     break;
-  case AvailabilityConstraint::Reason::Obsoleted:
+  case AvailabilityConstraint::Reason::UnavailableObsolete:
     diags
-        .diagnose(D, diag::availability_obsoleted, D, domain,
-                  Attr.getObsoletedRange(ctx).value())
+        .diagnose(D, diag::availability_obsoleted, D,
+                  domainAndRange.getDomain(), domainAndRange.getRange())
         .highlight(sourceRange);
     break;
-  case AvailabilityConstraint::Reason::PotentiallyUnavailable:
+  case AvailabilityConstraint::Reason::Unintroduced:
     llvm_unreachable("unexpected constraint");
     break;
   }
@@ -2191,7 +2206,7 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
   /// Models how member references will translate to accessor usage. This is
   /// used to diagnose the availability of individual accessors that may be
   /// called by the expression being checked.
-  enum class MemberAccessContext : unsigned {
+  enum class MemberAccessContext : uint8_t {
     /// The starting access context for the root of any expression tree. In this
     /// context, a member access will call the get accessor only.
     Default,
@@ -2212,11 +2227,45 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
     Writeback
   };
 
+  /// Models how key path references will translate to accessor usage. This is
+  /// used to diagnose the availability of individual accessors that may be
+  /// called by the expression being checked.
+  enum class KeyPathAccessContext : uint8_t {
+    /// The context does not involve a key path access.
+    None,
+
+    /// The context is a key path application (`x[keyPath: \.member]`).
+    Application,
+  };
+
   ASTContext &Context;
-  MemberAccessContext AccessContext = MemberAccessContext::Default;
   SmallVector<const Expr *, 16> ExprStack;
   SmallVector<bool, 4> PreconcurrencyCalleeStack;
   const ExportContext &Where;
+  MemberAccessContext MemberAccess = MemberAccessContext::Default;
+  KeyPathAccessContext KeyPathAccess = KeyPathAccessContext::None;
+  bool InInOutExpr = false;
+
+  /// A categorization of which accessors are used by a given storage access.
+  enum class StorageAccessKind {
+    Get,
+    Set,
+    GetSet,
+  };
+
+  /// Returns the storage access kind as indicated by the current member access
+  /// context.
+  StorageAccessKind getMemberStorageAccessKind() const {
+    switch (MemberAccess) {
+    case MemberAccessContext::Default:
+    case MemberAccessContext::Load:
+      return StorageAccessKind::Get;
+    case MemberAccessContext::Assignment:
+      return StorageAccessKind::Set;
+    case MemberAccessContext::Writeback:
+      return StorageAccessKind::GetSet;
+    }
+  }
 
 public:
   explicit ExprAvailabilityWalker(const ExportContext &Where)
@@ -2225,7 +2274,7 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
   PreWalkAction walkToArgumentPre(const Argument &Arg) override {
     // Arguments should be walked in their own member access context which
     // starts out read-only by default.
-    walkInContext(Arg.getExpr(), MemberAccessContext::Default);
+    walkInMemberAccessContext(Arg.getExpr(), MemberAccessContext::Default);
     return Action::SkipChildren();
   }
 
@@ -2242,7 +2291,8 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
     if (auto DR = dyn_cast<DeclRefExpr>(E)) {
       diagnoseDeclRefAvailability(DR->getDeclRef(), DR->getSourceRange(),
                                   getEnclosingApplyExpr(), std::nullopt);
-      maybeDiagStorageAccess(DR->getDecl(), DR->getSourceRange(), DC);
+      maybeDiagStorageAccess(DR->getDecl(), getMemberStorageAccessKind(),
+                             DR->getSourceRange(), DC);
     }
     if (auto MR = dyn_cast<MemberRefExpr>(E)) {
       walkMemberRef(MR);
@@ -2261,7 +2311,9 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
     if (auto S = dyn_cast<SubscriptExpr>(E)) {
       if (S->hasDecl()) {
         diagnoseDeclRefAvailability(S->getDecl(), S->getSourceRange(), S);
-        maybeDiagStorageAccess(S->getDecl().getDecl(), S->getSourceRange(), DC);
+        maybeDiagStorageAccess(S->getDecl().getDecl(),
+                               getMemberStorageAccessKind(),
+                               S->getSourceRange(), DC);
         PreconcurrencyCalleeStack.push_back(
             hasReferenceToPreconcurrencyDecl(S));
       }
@@ -2311,6 +2363,12 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
     if (auto KP = dyn_cast<KeyPathExpr>(E)) {
       maybeDiagKeyPath(KP);
     }
+    if (auto KPAE = dyn_cast<KeyPathApplicationExpr>(E)) {
+      KPAE->getBase()->walk(*this);
+      walkInKeyPathAccessContext(KPAE->getKeyPath(),
+                                 KeyPathAccessContext::Application);
+      return Action::SkipChildren(E);
+    }
     if (auto A = dyn_cast<AssignExpr>(E)) {
       // Attempting to assign to a @preconcurrency declaration should
       // downgrade Sendable conformance mismatches to warnings.
@@ -2389,7 +2447,7 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
     }
 
     if (auto LE = dyn_cast<LoadExpr>(E)) {
-      walkLoadExpr(LE);
+      walkInMemberAccessContext(LE->getSubExpr(), MemberAccessContext::Load);
       return Action::SkipChildren(E);
     }
 
@@ -2476,19 +2534,14 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
     // encountered walking (pre-order) is the Dest is the destination of the
     // write. For the moment this is fine -- but future syntax might violate
     // this assumption.
-    walkInContext(Dest, MemberAccessContext::Assignment);
+    walkInMemberAccessContext(Dest, MemberAccessContext::Assignment);
 
     // Check RHS in getter context
     Expr *Source = E->getSrc();
     if (!Source) {
       return;
     }
-    walkInContext(Source, MemberAccessContext::Default);
-  }
-
-  /// Walk a load expression, checking for availability.
-  void walkLoadExpr(LoadExpr *E) {
-    walkInContext(E->getSubExpr(), MemberAccessContext::Load);
+    walkInMemberAccessContext(Source, MemberAccessContext::Default);
   }
 
   /// Walk a member reference expression, checking for availability.
@@ -2504,10 +2557,10 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
     //           ╰─── MemberAccessContext::Writeback
     //
     MemberAccessContext accessContext =
-        (AccessContext == MemberAccessContext::Assignment)
+        (MemberAccess == MemberAccessContext::Assignment)
             ? MemberAccessContext::Writeback
-            : AccessContext;
-    walkInContext(E->getBase(), accessContext);
+            : MemberAccess;
+    walkInMemberAccessContext(E->getBase(), accessContext);
 
     ConcreteDeclRef DR = E->getMember();
     // Diagnose for the member declaration itself.
@@ -2517,7 +2570,62 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
 
     // Diagnose for appropriate accessors, given the access context.
     auto *DC = Where.getDeclContext();
-    maybeDiagStorageAccess(DR.getDecl(), E->getSourceRange(), DC);
+    maybeDiagStorageAccess(DR.getDecl(), getMemberStorageAccessKind(),
+                           E->getSourceRange(), DC);
+  }
+
+  StorageAccessKind getStorageAccessKindForKeyPath(KeyPathExpr *KP) const {
+    switch (KeyPathAccess) {
+    case KeyPathAccessContext::None: {
+      // Obj-C key paths are always considered mutable.
+      if (KP->isObjC())
+        return StorageAccessKind::GetSet;
+
+      // Check whether key path type indicates immutability, in which case only
+      // the getter will be used.
+      if (auto keyPathType = KP->getKeyPathType())
+        if (keyPathType->isKnownImmutableKeyPathType())
+          return StorageAccessKind::Get;
+
+      // Check if there's a conversion expression containing this one directly
+      // above it in the stack. If so, and that conversion is to an immutable
+      // key path type, then we should infer that use of the key path only
+      // implies use of the getter.
+      ArrayRef<const Expr *> exprs = ExprStack;
+      // Must be called while visiting the given key path expression.
+      ASSERT(exprs.back() == KP);
+
+      for (auto *expr : llvm::reverse(exprs.drop_back())) {
+        // Only traverse through conversions on the stack.
+        if (!isa<ImplicitConversionExpr>(expr) &&
+            !isa<OpenExistentialExpr>(expr))
+          break;
+
+        if (auto ty = expr->getType()) {
+          if (ty->isKnownImmutableKeyPathType())
+            return StorageAccessKind::Get;
+
+          if (auto existential = dyn_cast<ExistentialType>(ty)) {
+            if (auto superclass =
+                    existential->getExistentialLayout().getSuperclass()) {
+              if (superclass->isKnownImmutableKeyPathType())
+                return StorageAccessKind::Get;
+            }
+          }
+        }
+      }
+
+      // We failed to prove that the key path is only used immutably,
+      // so diagnose both get and set access.
+      return StorageAccessKind::GetSet;
+    }
+
+    case KeyPathAccessContext::Application:
+      // The key path is being applied directly to a base so treat it as if it
+      // were a direct access to the member in the current member access
+      // context.
+      return getMemberStorageAccessKind();
+    }
   }
 
   /// Walk a keypath expression, checking all of its components for
@@ -2528,6 +2636,8 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
     if (KP->isObjC())
       flags = DeclAvailabilityFlag::ForObjCKeyPath;
 
+    auto accessKind = getStorageAccessKindForKeyPath(KP);
+
     for (auto &component : KP->getComponents()) {
       switch (component.getKind()) {
       case KeyPathExpr::Component::Kind::Member:
@@ -2537,7 +2647,7 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
         auto range = component.getSourceRange();
         if (diagnoseDeclRefAvailability(decl, loc, nullptr, flags))
           break;
-        maybeDiagStorageAccess(decl.getDecl(), range, declContext);
+        maybeDiagStorageAccess(decl.getDecl(), accessKind, range, declContext);
         break;
       }
 
@@ -2562,13 +2672,15 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
 
   /// Walk an inout expression, checking for availability.
   void walkInOutExpr(InOutExpr *E) {
+    llvm::SaveAndRestore<bool> S(this->InInOutExpr, true);
+
     // Typically an InOutExpr should begin a `Writeback` context. However,
     // inside a LoadExpr this transition is suppressed since the entire
     // expression is being coerced to an r-value.
-    auto accessContext = AccessContext != MemberAccessContext::Load
+    auto accessContext = MemberAccess != MemberAccessContext::Load
                              ? MemberAccessContext::Writeback
-                             : AccessContext;
-    walkInContext(E->getSubExpr(), accessContext);
+                             : MemberAccess;
+    walkInMemberAccessContext(E->getSubExpr(), accessContext);
   }
 
   /// Walk an abstract closure expression, checking for availability
@@ -2585,16 +2697,23 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
     return;
   }
 
-  /// Walk the given expression in the member access context.
-  void walkInContext(Expr *E, MemberAccessContext AccessContext) {
-    llvm::SaveAndRestore<MemberAccessContext>
-      C(this->AccessContext, AccessContext);
+  /// Walk the given expression in a specific member access context.
+  void walkInMemberAccessContext(Expr *E, MemberAccessContext AccessContext) {
+    llvm::SaveAndRestore<MemberAccessContext> C(this->MemberAccess,
+                                                AccessContext);
+    E->walk(*this);
+  }
+
+  /// Walk the given expression in a specific key path access context.
+  void walkInKeyPathAccessContext(Expr *E, KeyPathAccessContext AccessContext) {
+    llvm::SaveAndRestore<KeyPathAccessContext> C(this->KeyPathAccess,
+                                                 AccessContext);
     E->walk(*this);
   }
 
   /// Emit diagnostics, if necessary, for accesses to storage where
   /// the accessor for the AccessContext is not available.
-  void maybeDiagStorageAccess(const ValueDecl *VD,
+  void maybeDiagStorageAccess(const ValueDecl *VD, StorageAccessKind accessKind,
                               SourceRange ReferenceRange,
                               const DeclContext *ReferenceDC) const {
     if (Context.LangOpts.DisableAvailabilityChecking)
@@ -2608,30 +2727,47 @@ class ExprAvailabilityWalker : public BaseDiagnosticWalker {
       return;
     }
 
+    // Avoid checking lazy property accessors if they haven't been
+    // synthesized yet, their availability is going to match the
+    // property itself. This is a workaround for lazy type-checking
+    // because synthesis of accessors for such properties requires
+    // a reference to `self` which won't be available because pattern
+    // binding for the variable was skipped.
+    //
+    // TODO: To fix this properly `getParentPatternBinding()`
+    // has to be refactored into a request to help establish association
+    // between a variable declaration and its pattern binding on demand
+    // instead of by using `typeCheckPatternBinding` called from the
+    // declaration checker.
+    if (D->getAttrs().hasAttribute<LazyAttr>()) {
+      auto *DC = D->getDeclContext();
+      if (DC->isTypeContext() && !(D->getAccessor(AccessorKind::Get) &&
+                                   D->getAccessor(AccessorKind::Set)))
+        return;
+    }
+
+    DeclAvailabilityFlags flags;
+    if (InInOutExpr)
+      flags |= DeclAvailabilityFlag::ForInout;
+
     // Check availability of accessor functions.
     // TODO: if we're talking about an inlineable storage declaration,
     // this probably needs to be refined to not assume that the accesses are
     // specifically using the getter/setter.
-    switch (AccessContext) {
-    case MemberAccessContext::Default:
-    case MemberAccessContext::Load:
+    switch (accessKind) {
+    case StorageAccessKind::Get:
       diagAccessorAvailability(D->getOpaqueAccessor(AccessorKind::Get),
-                               ReferenceRange, ReferenceDC, std::nullopt);
+                               ReferenceRange, ReferenceDC, flags);
       break;
-
-    case MemberAccessContext::Assignment:
+    case StorageAccessKind::Set:
       diagAccessorAvailability(D->getOpaqueAccessor(AccessorKind::Set),
-                               ReferenceRange, ReferenceDC, std::nullopt);
+                               ReferenceRange, ReferenceDC, flags);
       break;
-
-    case MemberAccessContext::Writeback:
+    case StorageAccessKind::GetSet:
       diagAccessorAvailability(D->getOpaqueAccessor(AccessorKind::Get),
-                               ReferenceRange, ReferenceDC,
-                               DeclAvailabilityFlag::ForInout);
-
+                               ReferenceRange, ReferenceDC, flags);
       diagAccessorAvailability(D->getOpaqueAccessor(AccessorKind::Set),
-                               ReferenceRange, ReferenceDC,
-                               DeclAvailabilityFlag::ForInout);
+                               ReferenceRange, ReferenceDC, flags);
       break;
     }
   }
@@ -2697,6 +2833,7 @@ diagnoseDeclUnsafe(ConcreteDeclRef declRef, SourceRange R,
 
   SourceLoc diagLoc = call ? call->getLoc() : R.Start;
   enumerateUnsafeUses(declRef, diagLoc, call != nullptr,
+                      /*skipTypeCheck=*/false,
                       [&](UnsafeUse unsafeUse) {
     unsafeUses->push_back(unsafeUse);
     return false;
@@ -2758,7 +2895,8 @@ static bool
 diagnoseDeclAsyncAvailability(const ValueDecl *D, SourceRange R,
                               const Expr *call, const ExportContext &Where) {
   // If we are not in an (effective) async context, don't check it
-  if (!shouldTreatDeclContextAsAsyncForDiagnostics(Where.getDeclContext()))
+  auto *noAsyncDC = getInnermostDeclContextForNoAsync(Where.getDeclContext());
+  if (!noAsyncDC->isAsyncContext())
     return false;
 
   ASTContext &ctx = Where.getDeclContext()->getASTContext();
@@ -2774,14 +2912,27 @@ diagnoseDeclAsyncAvailability(const ValueDecl *D, SourceRange R,
     }
   }
 
+  // In Swift 6 we previously didn't coerce macro arguments to parameter types,
+  // so closure arguments may be treated as async in cases where they weren't in
+  // Swift 6. As such we need to warn if the use is within a closure macro
+  // argument until the next language mode.
+  auto shouldWarnUntilFutureVersion = [&]() {
+    auto *CE = dyn_cast<ClosureExpr>(noAsyncDC);
+    return CE && CE->isMacroArgument();
+  };
+
   // @available(noasync) spelling
   if (auto attr = D->getNoAsyncAttr()) {
     SourceLoc diagLoc = call ? call->getLoc() : R.Start;
     auto diag = ctx.Diags.diagnose(diagLoc, diag::async_unavailable_decl, D,
                                    attr->getMessage());
-    diag.warnUntilSwiftVersion(6);
-    diag.limitBehaviorWithPreconcurrency(DiagnosticBehavior::Warning,
-                                         D->preconcurrency());
+    if (D->preconcurrency()) {
+      diag.limitBehavior(DiagnosticBehavior::Warning);
+    } else if (shouldWarnUntilFutureVersion()) {
+      diag.warnUntilFutureSwiftVersion();
+    } else {
+      diag.warnUntilSwiftVersion(6);
+    }
 
     if (!attr->getRename().empty()) {
       fixItAvailableAttrRename(diag, R, D, attr->getRename(), call);
@@ -2797,10 +2948,16 @@ diagnoseDeclAsyncAvailability(const ValueDecl *D, SourceRange R,
   // @_unavailableFromAsync spelling
   const UnavailableFromAsyncAttr *attr =
       D->getAttrs().getAttribute<UnavailableFromAsyncAttr>();
-  SourceLoc diagLoc = call ? call->getLoc() : R.Start;
-  ctx.Diags
-      .diagnose(diagLoc, diag::async_unavailable_decl, D, attr->Message)
-      .warnUntilSwiftVersion(6);
+  {
+    SourceLoc diagLoc = call ? call->getLoc() : R.Start;
+    auto diag = ctx.Diags.diagnose(diagLoc, diag::async_unavailable_decl, D,
+                                   attr->Message);
+    if (shouldWarnUntilFutureVersion()) {
+      diag.warnUntilFutureSwiftVersion();
+    } else {
+      diag.warnUntilSwiftVersion(6);
+    }
+  }
   D->diagnose(diag::decl_declared_here, D);
   return true;
 }
@@ -2864,27 +3021,26 @@ bool swift::diagnoseDeclAvailability(const ValueDecl *D, SourceRange R,
         && isa<ProtocolDecl>(D))
     return false;
 
-  if (!constraint)
-    return false;
-
   // Diagnose (and possibly signal) for potential unavailability
-  auto domain = constraint->getDomain();
-  auto requiredRange = constraint->getPotentiallyUnavailableRange(ctx);
-  if (!requiredRange)
+  if (!constraint || constraint->isUnavailable())
     return false;
 
+  auto domainAndRange = constraint->getDomainAndRange(ctx);
+  auto domain = domainAndRange.getDomain();
+  auto requiredRange = domainAndRange.getRange();
+
   if (Flags.contains(
           DeclAvailabilityFlag::
               AllowPotentiallyUnavailableAtOrBelowDeploymentTarget) &&
-      requiresDeploymentTargetOrEarlier(domain, *requiredRange, ctx))
+      requiresDeploymentTargetOrEarlier(domain, requiredRange, ctx))
     return false;
 
   if (accessor) {
     bool forInout = Flags.contains(DeclAvailabilityFlag::ForInout);
     diagnosePotentialAccessorUnavailability(accessor, R, DC, domain,
-                                            *requiredRange, forInout);
+                                            requiredRange, forInout);
   } else {
-    if (!diagnosePotentialUnavailability(D, R, DC, domain, *requiredRange))
+    if (!diagnosePotentialUnavailability(D, R, DC, domain, requiredRange))
       return false;
   }
 
@@ -2942,7 +3098,7 @@ ExprAvailabilityWalker::diagnoseIncDecRemoval(const ValueDecl *D, SourceRange R)
     // If we emit a deprecation diagnostic, produce a fixit hint as well.
     auto diag =
         Context.Diags.diagnose(R.Start, diag::availability_decl_unavailable, D,
-                               true, AvailabilityDomain::forSwiftLanguage(),
+                               true, AvailabilityDomain::forSwiftLanguageMode(),
                                "it has been removed in Swift 3");
     if (isa<PrefixUnaryExpr>(call)) {
       // Prefix: remove the ++ or --.
@@ -2991,7 +3147,7 @@ ExprAvailabilityWalker::diagnoseMemoryLayoutMigration(const ValueDecl *D,
   EncodedDiagnosticMessage EncodedMessage(Attr.getMessage());
   auto diag = Context.Diags.diagnose(
       R.Start, diag::availability_decl_unavailable, D, true,
-      AvailabilityDomain::forSwiftLanguage(), EncodedMessage.Message);
+      AvailabilityDomain::forSwiftLanguageMode(), EncodedMessage.Message);
   diag.highlight(R);
 
   StringRef Prefix = "MemoryLayout<";
@@ -3297,8 +3453,15 @@ void swift::diagnoseTypeAvailability(const TypeRepr *TR, Type T, SourceLoc loc,
 static void diagnoseMissingConformance(
     SourceLoc loc, Type type, ProtocolDecl *proto, const DeclContext *fromDC,
     bool preconcurrency) {
-  assert(proto->isSpecificProtocol(KnownProtocolKind::Sendable));
-  diagnoseMissingSendableConformance(loc, type, fromDC, preconcurrency);
+  assert(proto->isSpecificProtocol(KnownProtocolKind::Sendable) ||
+         proto->isSpecificProtocol(KnownProtocolKind::SendableMetatype));
+
+  if (proto->isSpecificProtocol(KnownProtocolKind::Sendable))
+    diagnoseMissingSendableConformance(loc, type, fromDC, preconcurrency);
+
+  if (proto->isSpecificProtocol(KnownProtocolKind::SendableMetatype))
+    diagnoseMissingSendableMetatypeConformance(loc, type, fromDC,
+                                               preconcurrency);
 }
 
 bool
@@ -3389,14 +3552,12 @@ swift::diagnoseConformanceAvailability(SourceLoc loc,
       }
 
       // Diagnose (and possibly signal) for potential unavailability
-      if (auto requiredRange =
-              constraint->getPotentiallyUnavailableRange(ctx)) {
-        if (diagnosePotentialUnavailability(rootConf, ext, loc, DC,
-                                            constraint->getDomain(),
-                                            *requiredRange)) {
-          maybeEmitAssociatedTypeNote();
-          return true;
-        }
+      auto domainAndRange = constraint->getDomainAndRange(ctx);
+      if (diagnosePotentialUnavailability(rootConf, ext, loc, DC,
+                                          domainAndRange.getDomain(),
+                                          domainAndRange.getRange())) {
+        maybeEmitAssociatedTypeNote();
+        return true;
       }
     }
 
@@ -3481,9 +3642,8 @@ static bool declNeedsExplicitAvailability(const Decl *decl) {
   if (decl->isUnavailable())
     return false;
 
-  // Warn on decls without an introduction version.
-  auto safeRangeUnderApprox = AvailabilityInference::availableRange(decl);
-  return safeRangeUnderApprox.isAlwaysAvailable();
+  // Warn on decls without a platform introduction version.
+  return !decl->getAvailableAttrForPlatformIntroduction();
 }
 
 void swift::checkExplicitAvailability(Decl *decl) {
@@ -3511,6 +3671,11 @@ void swift::checkExplicitAvailability(Decl *decl) {
       !isa<ExtensionDecl>(decl->getDeclContext())) return;
 
   if (auto extension = dyn_cast<ExtensionDecl>(decl)) {
+    // Skip extensions that extend non-public types.
+    auto extended = extension->getExtendedNominal();
+    if (!extended || !extended->getFormalAccessScope().isPublic())
+      return;
+
     // Skip extensions when none of their members need availability.
     auto members = extension->getMembers();
     auto hasMembers = std::any_of(members.begin(), members.end(),
diff --git a/lib/Sema/TypeCheckAvailability.h b/lib/Sema/TypeCheckAvailability.h
index c14c525b44df8..30d5051de022a 100644
--- a/lib/Sema/TypeCheckAvailability.h
+++ b/lib/Sema/TypeCheckAvailability.h
@@ -77,7 +77,8 @@ enum class ExportabilityReason : unsigned {
   ResultBuilder,
   ExtensionWithPublicMembers,
   ExtensionWithConditionalConformances,
-  Inheritance
+  Inheritance,
+  AvailableAttribute,
 };
 
 /// A description of the restrictions on what declarations can be referenced
diff --git a/lib/Sema/TypeCheckBitwise.cpp b/lib/Sema/TypeCheckBitwise.cpp
index e20898676be42..7d66c312cf24b 100644
--- a/lib/Sema/TypeCheckBitwise.cpp
+++ b/lib/Sema/TypeCheckBitwise.cpp
@@ -377,8 +377,8 @@ NormalProtocolConformance *
 DeriveImplicitBitwiseCopyableConformance::synthesizeConformance(
     DeclContext *dc) {
   auto conformance = context.getNormalConformance(
-      nominal->getDeclaredInterfaceType(), protocol, nominal->getLoc(), dc,
-      ProtocolConformanceState::Complete,
+      nominal->getDeclaredInterfaceType(), protocol, nominal->getLoc(),
+      /*inheritedTypeRepr=*/nullptr, dc, ProtocolConformanceState::Complete,
       ProtocolConformanceOptions());
   conformance->setSourceKindAndImplyingConformance(
       ConformanceEntryKind::Synthesized, nullptr);
diff --git a/lib/Sema/TypeCheckCaptures.cpp b/lib/Sema/TypeCheckCaptures.cpp
index f9018cec54c0e..be0054a709067 100644
--- a/lib/Sema/TypeCheckCaptures.cpp
+++ b/lib/Sema/TypeCheckCaptures.cpp
@@ -66,6 +66,7 @@ class FindCapturedVars : public ASTWalker {
   DeclContext *CurDC;
   bool NoEscape, ObjC;
   bool HasGenericParamCaptures;
+  bool HasUsesOfCurrentIsolation = false;
 
 public:
   FindCapturedVars(SourceLoc CaptureLoc,
@@ -91,6 +92,10 @@ class FindCapturedVars : public ASTWalker {
                        CapturedTypes);
   }
 
+  bool hasUsesOfCurrentIsolation() const {
+    return HasUsesOfCurrentIsolation;
+  }
+
   bool hasGenericParamCaptures() const {
     return HasGenericParamCaptures;
   }
@@ -364,9 +369,8 @@ class FindCapturedVars : public ASTWalker {
         // }
         if (!isa<FuncDecl>(D)) {
           if (DC->isLocalContext()) {
-            Context.Diags.diagnose(DRE->getLoc(), diag::capture_across_type_decl,
-                                   NTD->getDescriptiveKind(),
-                                   D->getBaseIdentifier());
+            Context.Diags.diagnose(DRE->getLoc(),
+                                   diag::capture_across_type_decl, NTD, D);
 
             NTD->diagnose(diag::kind_declared_here,
                           DescriptiveDeclKind::Type);
@@ -396,13 +400,11 @@ class FindCapturedVars : public ASTWalker {
     // If this is a direct reference to underlying storage, then this is a
     // capture of the storage address - not a capture of the getter/setter.
     if (auto var = dyn_cast<VarDecl>(D)) {
-      if (var->getAccessStrategy(DRE->getAccessSemantics(),
-                                 var->supportsMutation() ? AccessKind::ReadWrite
-                                                         : AccessKind::Read,
-                                 CurDC->getParentModule(),
-                                 CurDC->getResilienceExpansion(),
-                                 /*useOldABI=*/false)
-              .getKind() == AccessStrategy::Storage)
+      if (var->isAccessedViaPhysicalStorage(
+              DRE->getAccessSemantics(),
+              var->supportsMutation() ? AccessKind::ReadWrite
+                                      : AccessKind::Read,
+              CurDC->getParentModule(), CurDC->getResilienceExpansion()))
         Flags |= CapturedValue::IsDirect;
     }
 
@@ -696,6 +698,31 @@ class FindCapturedVars : public ASTWalker {
       checkType(typeValue->getParamType(), E->getLoc());
     }
 
+    // Record that we saw an #isolation expression that hasn't been filled in.
+    if (auto currentIsolation = dyn_cast<CurrentContextIsolationExpr>(E)) {
+      if (!currentIsolation->getActor())
+        HasUsesOfCurrentIsolation = true;
+    }
+
+    // Record that we saw an apply of a function with caller isolation.
+    if (auto apply = dyn_cast<ApplyExpr>(E)) {
+      if (auto type = apply->getFn()->getType()) {
+        if (auto fnType = type->getAs<AnyFunctionType>();
+            fnType && fnType->getIsolation().isNonIsolatedCaller()) {
+          HasUsesOfCurrentIsolation = true;
+        }
+      }
+    }
+
+    // Look into caller-side default arguments.
+    if (auto defArg = dyn_cast<DefaultArgumentExpr>(E)) {
+      if (defArg->isCallerSide()) {
+        if (auto callerSideExpr = defArg->getCallerSideDefaultExpr()) {
+          callerSideExpr->walk(*this);
+        }
+      }
+    }
+
     return Action::Continue(E);
   }
 
@@ -747,6 +774,36 @@ class FindCapturedVars : public ASTWalker {
 
 } // end anonymous namespace
 
+/// Given that a local function is isolated to the given var, should we
+/// force a capture of the var?
+static bool shouldCaptureIsolationInLocalFunc(AbstractFunctionDecl *AFD,
+                                              VarDecl *var,
+                                              bool hasUsesOfCurrentIsolation) {
+  assert(isa<ParamDecl>(var));
+
+  // Don't try to capture an isolated parameter of the function itself.
+  if (var->getDeclContext() == AFD)
+    return false;
+
+  // Force capture if we have uses of the isolation in the function body.
+  if (hasUsesOfCurrentIsolation)
+    return true;
+
+  // We only *need* to force a capture of the isolation in an async function
+  // (in which case it's needed for executor switching) or if we're in the
+  // mode that forces an executor check in all synchronous functions. But
+  // it's a simpler rule if we just do it unconditionally.
+
+  // However, don't do it for the implicit functions that represent defer
+  // bodies, where it is both unnecessary and likely to lead to bad diagnostics.
+  // We already suppress the executor check in defer bodies.
+  if (auto FD = dyn_cast<FuncDecl>(AFD))
+    if (FD->isDeferBody())
+      return false;
+
+  return true;
+}
+
 CaptureInfo CaptureInfoRequest::evaluate(Evaluator &evaluator,
                                          AbstractFunctionDecl *AFD) const {
   auto type = AFD->getInterfaceType();
@@ -764,16 +821,14 @@ CaptureInfo CaptureInfoRequest::evaluate(Evaluator &evaluator,
     finder.checkType(type, AFD->getLoc());
   }
 
-  if (AFD->isLocalCapture() && AFD->hasAsync()) {
+  if (AFD->isLocalCapture()) {
     // If a local function inherits isolation from the enclosing context,
     // make sure we capture the isolated parameter, if we haven't already.
     auto actorIsolation = getActorIsolation(AFD);
     if (actorIsolation.getKind() == ActorIsolation::ActorInstance) {
       if (auto *var = actorIsolation.getActorInstance()) {
-        assert(isa<ParamDecl>(var));
-        // Don't capture anything if the isolation parameter is a parameter
-        // of the local function.
-        if (var->getDeclContext() != AFD)
+        if (shouldCaptureIsolationInLocalFunc(AFD, var,
+                                              finder.hasUsesOfCurrentIsolation()))
           finder.addCapture(CapturedValue(var, 0, AFD->getLoc()));
       }
     }
@@ -790,8 +845,9 @@ CaptureInfo CaptureInfoRequest::evaluate(Evaluator &evaluator,
         std::optional<ForeignAsyncConvention> asyncConvention;
         std::optional<ForeignErrorConvention> errorConvention;
         if (!AFD->isObjC() &&
-            isRepresentableInObjC(AFD, ObjCReason::MemberOfObjCMembersClass,
-                                  asyncConvention, errorConvention)) {
+            isRepresentableInLanguage(AFD,
+                                      ObjCReason::MemberOfObjCMembersClass,
+                                      asyncConvention, errorConvention)) {
           AFD->diagnose(
                    diag::objc_generic_extension_using_type_parameter_try_objc)
             .fixItInsert(AFD->getAttributeInsertionLoc(false), "@objc ");
@@ -857,43 +913,30 @@ CaptureInfo ParamCaptureInfoRequest::evaluate(Evaluator &evaluator,
   return finder.getCaptureInfo();
 }
 
-static bool isLazy(PatternBindingDecl *PBD) {
-  if (auto var = PBD->getSingleVar())
-    return var->getAttrs().hasAttribute<LazyAttr>();
-  return false;
-}
-
-void TypeChecker::checkPatternBindingCaptures(IterableDeclContext *DC) {
-  for (auto member : DC->getMembers()) {
-    // Ignore everything other than PBDs.
-    auto *PBD = dyn_cast<PatternBindingDecl>(member);
-    if (!PBD) continue;
-    // Walk the initializers for all properties declared in the type with
-    // an initializer.
-    for (unsigned i : range(PBD->getNumPatternEntries())) {
-      if (PBD->isInitializerSubsumed(i))
-        continue;
+CaptureInfo PatternBindingCaptureInfoRequest::evaluate(Evaluator &evaluator,
+                                                       PatternBindingDecl *PBD,
+                                                       unsigned int idx) const {
+  auto *init = PBD->getExecutableInit(idx);
+  if (!init)
+    return CaptureInfo::empty();
 
-      auto *init = PBD->getInit(i);
-      if (init == nullptr)
-        continue;
+  // Only have captures when we have a PatternBindingInitializer context, i.e
+  // local variables don't have captures.
+  auto *DC = PBD->getInitContext(idx);
+  if (!DC)
+    return CaptureInfo::empty();
 
-      auto *DC = PBD->getInitContext(i);
-      FindCapturedVars finder(init->getLoc(),
-                              DC,
-                              /*NoEscape=*/false,
-                              /*ObjC=*/false,
-                              /*IsGenericFunction*/false);
-      init->walk(finder);
-
-      auto &ctx = DC->getASTContext();
-      if (finder.getDynamicSelfCaptureLoc().isValid() && !isLazy(PBD)) {
-        ctx.Diags.diagnose(finder.getDynamicSelfCaptureLoc(),
-                           diag::dynamic_self_stored_property_init);
-      }
+  FindCapturedVars finder(init->getLoc(), DC,
+                          /*NoEscape=*/false,
+                          /*ObjC=*/false,
+                          /*IsGenericFunction*/ false);
+  init->walk(finder);
 
-      auto captures = finder.getCaptureInfo();
-      PBD->setCaptureInfo(i, captures);
-    }
+  auto &ctx = DC->getASTContext();
+  if (finder.getDynamicSelfCaptureLoc().isValid()) {
+    ctx.Diags.diagnose(finder.getDynamicSelfCaptureLoc(),
+                       diag::dynamic_self_stored_property_init);
   }
+
+  return finder.getCaptureInfo();
 }
diff --git a/lib/Sema/TypeCheckCodeCompletion.cpp b/lib/Sema/TypeCheckCodeCompletion.cpp
index 2728c88bc2187..a9edda330d98c 100644
--- a/lib/Sema/TypeCheckCodeCompletion.cpp
+++ b/lib/Sema/TypeCheckCodeCompletion.cpp
@@ -198,7 +198,7 @@ void TypeChecker::filterSolutionsForCodeCompletion(
 }
 
 bool TypeChecker::typeCheckForCodeCompletion(
-    SyntacticElementTarget &target, bool needsPrecheck,
+    SyntacticElementTarget &target,
     llvm::function_ref<void(const Solution &)> callback) {
   auto *DC = target.getDeclContext();
   auto &Context = DC->getASTContext();
@@ -211,88 +211,32 @@ bool TypeChecker::typeCheckForCodeCompletion(
       return false;
   }
 
-  CompletionContextFinder contextAnalyzer(target, DC);
+  CompletionContextFinder contextAnalyzer(target);
 
   // If there was no completion expr (e.g. if the code completion location was
   // among tokens that were skipped over during parser error recovery) bail.
   if (!contextAnalyzer.hasCompletion())
     return false;
 
-  if (needsPrecheck) {
-    // First, pre-check the expression, validating any types that occur in the
-    // expression and folding sequence expressions.
-    auto failedPreCheck = ConstraintSystem::preCheckTarget(target);
-    if (failedPreCheck)
-      return false;
-  }
+  ConstraintSystemOptions options;
+  options |= ConstraintSystemFlags::AllowFixes;
+  options |= ConstraintSystemFlags::SuppressDiagnostics;
+  options |= ConstraintSystemFlags::ForCodeCompletion;
 
-  enum class CompletionResult { Ok, NotApplicable, Fallback };
-
-  auto solveForCodeCompletion =
-      [&](SyntacticElementTarget &target) -> CompletionResult {
-    ConstraintSystemOptions options;
-    options |= ConstraintSystemFlags::AllowFixes;
-    options |= ConstraintSystemFlags::SuppressDiagnostics;
-    options |= ConstraintSystemFlags::ForCodeCompletion;
-    
-    ConstraintSystem cs(DC, options);
-
-    llvm::SmallVector<Solution, 4> solutions;
-
-    // If solve failed to generate constraints or with some other
-    // issue, we need to fallback to type-checking a sub-expression.
-    cs.setTargetFor(target.getAsExpr(), target);
-    if (!cs.solveForCodeCompletion(target, solutions))
-      return CompletionResult::Fallback;
-
-    // Similarly, if the type-check didn't produce any solutions, fall back
-    // to type-checking a sub-expression in isolation.
-    if (solutions.empty())
-      return CompletionResult::Fallback;
-
-    // FIXME: instead of filtering, expose the score and viability to clients.
-    // Remove solutions that skipped over/ignored the code completion point
-    // or that require fixes and have a score that is worse than the best.
-    filterSolutionsForCodeCompletion(solutions, contextAnalyzer);
-
-    llvm::for_each(solutions, callback);
-    return CompletionResult::Ok;
-  };
+  ConstraintSystem cs(DC, options);
 
-  switch (solveForCodeCompletion(target)) {
-  case CompletionResult::Ok:
-    return true;
+  llvm::SmallVector<Solution, 4> solutions;
 
-  case CompletionResult::NotApplicable:
-    return false;
+  cs.setTargetFor(target.getAsExpr(), target);
+  if (!cs.solveForCodeCompletion(target, solutions) || solutions.empty())
+    return true;
 
-  case CompletionResult::Fallback:
-    break;
-  }
+  // FIXME: instead of filtering, expose the score and viability to clients.
+  // Remove solutions that skipped over/ignored the code completion point
+  // or that require fixes and have a score that is worse than the best.
+  filterSolutionsForCodeCompletion(solutions, contextAnalyzer);
 
-  // Determine the best subexpression to use based on the collected context
-  // of the code completion expression.
-  auto fallback = contextAnalyzer.getFallbackCompletionExpr();
-  if (!fallback) {
-    return true;
-  }
-  if (isa<AbstractClosureExpr>(fallback->DC)) {
-    // If the expression is embedded in a closure, the constraint system tries
-    // to retrieve that closure's type, which will fail since we won't have
-    // generated any type variables for it. Thus, fallback type checking isn't
-    // available in this case.
-    return true;
-  }
-  if (auto *expr = target.getAsExpr()) {
-    assert(fallback->E != expr);
-    (void)expr;
-  }
-  SyntacticElementTarget completionTarget(fallback->E, fallback->DC,
-                                          CTP_Unused,
-                                          /*contextualType=*/Type(),
-                                          /*isDiscarded=*/true);
-  typeCheckForCodeCompletion(completionTarget, fallback->SeparatePrecheck,
-                             callback);
+  llvm::for_each(solutions, callback);
   return true;
 }
 
diff --git a/lib/Sema/TypeCheckConcurrency.cpp b/lib/Sema/TypeCheckConcurrency.cpp
index 0dbf4a25aa89e..83c46014544b5 100644
--- a/lib/Sema/TypeCheckConcurrency.cpp
+++ b/lib/Sema/TypeCheckConcurrency.cpp
@@ -15,15 +15,14 @@
 //===----------------------------------------------------------------------===//
 
 #include "TypeCheckConcurrency.h"
-#include "AsyncCallerExecutionMigration.h"
 #include "MiscDiagnostics.h"
+#include "NonisolatedNonsendingByDefaultMigration.h"
 #include "TypeCheckDistributed.h"
 #include "TypeCheckInvertible.h"
 #include "TypeCheckProtocol.h"
 #include "TypeCheckType.h"
 #include "TypeChecker.h"
 #include "swift/AST/ASTWalker.h"
-#include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/Concurrency.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/DistributedDecl.h"
@@ -41,6 +40,7 @@
 #include "swift/Strings.h"
 
 using namespace swift;
+using namespace swift::version;
 
 static ActorIsolation getOverriddenIsolationFor(const ValueDecl *value);
 
@@ -371,7 +371,7 @@ GlobalActorAttributeRequest::evaluate(
     // This is a workaround for rdar://79563942
     loc = decl->getLoc(/* SerializedOK */ false);
   } else {
-    auto closure = subject.get<ClosureExpr *>();
+    auto closure = cast<ClosureExpr *>(subject);
     dc = closure;
     declAttrs = &closure->getAttrs();
     loc = closure->getLoc();
@@ -390,13 +390,13 @@ GlobalActorAttributeRequest::evaluate(
     return std::nullopt;
 
   // Closures can always have a global actor attached.
-  if (subject.is<ClosureExpr *>()) {
+  if (isa<ClosureExpr *>(subject)) {
     return result;
   }
 
   // Check that a global actor attribute makes sense on this kind of
   // declaration.
-  auto decl = subject.get<Decl *>();
+  auto decl = cast<Decl *>(subject);
 
   // no further checking required if it's from a serialized module.
   if (decl->getDeclContext()->getParentSourceFile() == nullptr)
@@ -451,8 +451,7 @@ GlobalActorAttributeRequest::evaluate(
     // to have a global actor attribute.
     if (auto *accessor = dyn_cast<AccessorDecl>(decl)) {
       if (!accessor->isGetter()) {
-        decl->diagnose(diag::global_actor_disallowed,
-                       decl->getDescriptiveKind())
+        decl->diagnose(diag::global_actor_disallowed, decl)
             .warnUntilSwiftVersion(6)
             .fixItRemove(globalActorAttr->getRangeWithAt());
 
@@ -493,7 +492,7 @@ GlobalActorAttributeRequest::evaluate(
     // Functions are okay.
   } else {
     // Everything else is disallowed.
-    decl->diagnose(diag::global_actor_disallowed, decl->getDescriptiveKind());
+    decl->diagnose(diag::global_actor_disallowed, decl);
     return std::nullopt;
   }
 
@@ -569,7 +568,7 @@ static bool varIsSafeAcrossActors(const ModuleDecl *fromModule, VarDecl *var,
     if (var->isGlobalStorage() && var->isLazilyInitializedGlobal()) {
       // Compiler versions <= 5.9 accepted this code, so downgrade to a
       // warning prior to Swift 6.
-      options = ActorReferenceResult::Flags::Preconcurrency;
+      options = ActorReferenceResult::Flags::CompatibilityDowngrade;
       return false;
     }
 
@@ -590,7 +589,7 @@ static bool varIsSafeAcrossActors(const ModuleDecl *fromModule, VarDecl *var,
       // so downgrade async access errors in the effects checker to
       // warnings prior to Swift 6.
       if (accessWithinModule)
-        options = ActorReferenceResult::Flags::Preconcurrency;
+        options = ActorReferenceResult::Flags::CompatibilityDowngrade;
 
       return false;
     }
@@ -695,7 +694,7 @@ static bool isAsyncCall(
     return funcType->isAsync();
   }
 
-  auto *lookup = call.get<LookupExpr *>();
+  auto *lookup = cast<LookupExpr *>(call);
   if (lookup->isImplicitlyAsync())
     return true;
 
@@ -765,18 +764,30 @@ static void addSendableFixIt(
   }
 }
 
-/// Add Fix-It text for the given generic param declaration type to adopt
-/// Sendable.
-static void addSendableFixIt(const GenericTypeParamDecl *genericArgument,
-                             InFlightDiagnostic &diag) {
+static void addProtocolFixIt(const GenericTypeParamDecl *genericArgument,
+                             InFlightDiagnostic &diag, StringRef protocolName) {
   if (genericArgument->getInherited().empty()) {
     auto fixItLoc = genericArgument->getLoc();
-    diag.fixItInsertAfter(fixItLoc, ": Sendable");
+    diag.fixItInsertAfter(fixItLoc, llvm::Twine(": ", protocolName).str());
   } else {
     auto fixItLoc = genericArgument->getInherited().getEndLoc();
-    diag.fixItInsertAfter(fixItLoc, " & Sendable");
+    diag.fixItInsertAfter(fixItLoc, llvm::Twine(" & ", protocolName).str());
   }
 }
+/// Add Fix-It text for the given generic param declaration type to adopt
+/// Sendable.
+static void addSendableFixIt(const GenericTypeParamDecl *genericArgument,
+                             InFlightDiagnostic &diag) {
+  addProtocolFixIt(genericArgument, diag,
+                   getProtocolName(KnownProtocolKind::Sendable));
+}
+
+static void
+addSendableMetatypeFixIt(const GenericTypeParamDecl *genericArgument,
+                         InFlightDiagnostic &diag) {
+  addProtocolFixIt(genericArgument, diag,
+                   getProtocolName(KnownProtocolKind::SendableMetatype));
+}
 
 static bool shouldDiagnoseExistingDataRaces(const DeclContext *dc) {
   return contextRequiresStrictConcurrencyChecking(dc, [](const AbstractClosureExpr *) {
@@ -798,7 +809,7 @@ bool SendableCheckContext::warnInMinimalChecking() const {
   case SendableCheck::Explicit:
     return true;
 
-  case SendableCheck::ImpliedByStandardProtocol:
+  case SendableCheck::ImpliedByPreconcurrencyProtocol:
   case SendableCheck::Implicit:
   case SendableCheck::ImplicitForExternallyVisible:
     return false;
@@ -879,6 +890,12 @@ SendableCheckContext::preconcurrencyBehavior(
   return std::nullopt;
 }
 
+std::optional<DiagnosticBehavior>
+SendableCheckContext::preconcurrencyBehavior(Type type) const {
+  return type->getConcurrencyDiagnosticBehaviorLimit(
+      const_cast<DeclContext *>(fromDC));
+}
+
 static bool shouldDiagnosePreconcurrencyImports(SourceFile &sf) {
   switch (sf.Kind) {
   case SourceFileKind::Interface:
@@ -1020,7 +1037,8 @@ static bool diagnoseSingleNonSendableType(
         if (genericParamTypeDecl &&
             genericParamTypeDecl->getModuleContext() == module) {
           auto diag = genericParamTypeDecl->diagnose(
-              diag::add_generic_parameter_sendable_conformance, type);
+              diag::add_generic_parameter_conformance, type,
+              ctx.getProtocol(KnownProtocolKind::Sendable));
           addSendableFixIt(genericParamTypeDecl, diag);
         }
       }
@@ -1034,11 +1052,17 @@ bool swift::diagnoseNonSendableTypes(
     Type type, SendableCheckContext fromContext,
     Type inDerivedConformance, SourceLoc loc,
     llvm::function_ref<bool(Type, DiagnosticBehavior)> diagnose) {
+  auto &ctx = type->getASTContext();
+
   // If the Sendable protocol is missing, do nothing.
-  auto proto = type->getASTContext().getProtocol(KnownProtocolKind::Sendable);
+  auto proto = ctx.getProtocol(KnownProtocolKind::Sendable);
   if (!proto)
     return false;
 
+  // Unwrap pack expansions here to allow packs of Sendable type.
+  if (auto *expansion = type->getAs<PackExpansionType>())
+    type = PackType::get(ctx, {expansion});
+
   // FIXME: More detail for unavailable conformances.
   auto conformance = lookupConformance(type, proto, /*allowMissing=*/true);
   if (conformance.isInvalid() || conformance.hasUnavailableConformance()) {
@@ -1168,34 +1192,47 @@ bool swift::diagnoseNonSendableTypesInReference(
       return true;
   }
 
-  // For functions, check the parameter and result types.
+  // For functions or subscripts, check the parameter and result types.
   SubstitutionMap subs = declRef.getSubstitutions();
-  if (auto function = dyn_cast<AbstractFunctionDecl>(declRef.getDecl())) {
+  auto decl = declRef.getDecl();
+  if (isa<AbstractFunctionDecl>(decl) || isa<SubscriptDecl>(decl)) {
     if (funcCheckOptions.contains(FunctionCheckKind::Params)) {
       // only check params if funcCheckKind specifies so
-      for (auto param : *function->getParameters()) {
+      ParameterList *paramList = nullptr;
+      if (auto function = dyn_cast<AbstractFunctionDecl>(decl)) {
+        paramList = function->getParameters();
+      } else if (auto subscript = dyn_cast<SubscriptDecl>(decl)) {
+        paramList = subscript->getIndices();
+      }
+
+      // Check params of this function or subscript override for sendability
+      for (auto param : *paramList) {
         Type paramType = param->getInterfaceType().subst(subs);
-        if (diagnoseNonSendableTypes(
-                paramType, fromDC, derivedConformanceType,
-                refLoc, diagnoseLoc.isInvalid() ? refLoc : diagnoseLoc,
-                getSendableParamDiag(refKind),
-                function, getActorIsolation()))
+        if (diagnoseNonSendableTypesWithSendingCheck(
+                param, paramType, fromDC, derivedConformanceType, refLoc,
+                diagnoseLoc.isInvalid() ? refLoc : diagnoseLoc,
+                getSendableParamDiag(refKind), decl, getActorIsolation()))
           return true;
       }
     }
 
-    // Check the result type of a function.
-    if (auto func = dyn_cast<FuncDecl>(function)) {
-      if (funcCheckOptions.contains(FunctionCheckKind::Results)) {
-        // only check results if funcCheckKind specifies so
-        Type resultType = func->getResultInterfaceType().subst(subs);
-        if (diagnoseNonSendableTypes(
-            resultType, fromDC, derivedConformanceType,
-            refLoc, diagnoseLoc.isInvalid() ? refLoc : diagnoseLoc,
-            getSendableResultDiag(refKind),
-            func, getActorIsolation()))
-          return true;
+    // Check the result type of a function or subscript.
+    if (funcCheckOptions.contains(FunctionCheckKind::Results)) {
+      Type resultType;
+      if (auto func = dyn_cast<FuncDecl>(decl)) {
+        resultType = func->getResultInterfaceType().subst(subs);
+        decl = func;
+      } else if (auto subscript = dyn_cast<SubscriptDecl>(decl)) {
+        resultType = subscript->getElementInterfaceType().subst(subs);
+      }
+      if (!resultType) {
+        return false;
       }
+      if (diagnoseNonSendableTypesWithSendingCheck(
+              decl, resultType, fromDC, derivedConformanceType, refLoc,
+              diagnoseLoc.isInvalid() ? refLoc : diagnoseLoc,
+              getSendableResultDiag(refKind), decl, getActorIsolation()))
+        return true;
     }
 
     return false;
@@ -1213,34 +1250,6 @@ bool swift::diagnoseNonSendableTypesInReference(
       return true;
   }
 
-  if (auto subscript = dyn_cast<SubscriptDecl>(declRef.getDecl())) {
-    for (auto param : *subscript->getIndices()) {
-      if (funcCheckOptions.contains(FunctionCheckKind::Params)) {
-        // Check params of this subscript override for sendability
-        Type paramType = param->getInterfaceType().subst(subs);
-        if (diagnoseNonSendableTypes(
-                paramType, fromDC, derivedConformanceType,
-                refLoc, diagnoseLoc.isInvalid() ? refLoc : diagnoseLoc,
-                getSendableParamDiag(refKind),
-                subscript, getActorIsolation()))
-          return true;
-      }
-    }
-
-    if (funcCheckOptions.contains(FunctionCheckKind::Results)) {
-      // Check the element type of a subscript.
-      Type resultType = subscript->getElementInterfaceType().subst(subs);
-      if (diagnoseNonSendableTypes(
-              resultType, fromDC, derivedConformanceType,
-              refLoc, diagnoseLoc.isInvalid() ? refLoc : diagnoseLoc,
-              getSendableResultDiag(refKind),
-              subscript, getActorIsolation()))
-        return true;
-    }
-
-    return false;
-  }
-
   return false;
 }
 
@@ -1252,6 +1261,32 @@ void swift::diagnoseMissingSendableConformance(
       loc, diag::non_sendable_type);
 }
 
+void swift::diagnoseMissingSendableMetatypeConformance(
+    SourceLoc loc, Type type, const DeclContext *fromDC, bool preconcurrency) {
+  SendableCheckContext sendableContext(fromDC, preconcurrency);
+  DiagnosticBehavior behavior =
+      sendableContext.implicitSendableDiagnosticBehavior();
+
+  auto &ctx = type->getASTContext();
+  ctx.Diags.diagnose(loc, diag::non_sendable_metatype_type, type)
+      .limitBehaviorWithPreconcurrency(behavior, preconcurrency);
+
+  if (auto genericArchetype = type->getAs<ArchetypeType>()) {
+    auto interfaceType = genericArchetype->getInterfaceType();
+    if (auto genericParamType = interfaceType->getAs<GenericTypeParamType>()) {
+      auto module = fromDC->getParentModule();
+      auto *genericParamTypeDecl = genericParamType->getDecl();
+      if (genericParamTypeDecl &&
+          genericParamTypeDecl->getModuleContext() == module) {
+        auto diag = genericParamTypeDecl->diagnose(
+            diag::add_generic_parameter_conformance, type,
+            ctx.getProtocol(KnownProtocolKind::SendableMetatype));
+        addSendableMetatypeFixIt(genericParamTypeDecl, diag);
+      }
+    }
+  }
+}
+
 namespace {
 /// Infer Sendable from the instance storage of the given nominal type.
 /// \returns \c std::nullopt if there is no way to make the type \c Sendable,
@@ -1380,35 +1415,34 @@ void swift::diagnoseMissingExplicitSendable(NominalTypeDecl *nominal) {
         isUnchecked = true;
     }
 
-    auto note = nominal->diagnose(
-        isUnchecked ? diag::explicit_unchecked_sendable
-                    : diag::add_nominal_sendable_conformance,
-        nominal);
-    if (canMakeSendable && !requirements.empty()) {
-      // Produce a Fix-It containing a conditional conformance to Sendable,
-      // based on the requirements harvested from instance storage.
-
-      // Form the where clause containing all of the requirements.
-      SmallString<64> whereClause;
-      {
-        llvm::raw_svector_ostream out(whereClause);
-        llvm::interleaveComma(
-            requirements, out,
-            [&](const Requirement &req) {
-              out << req.getFirstType().getString() << ": "
-                  << req.getSecondType().getString();
-            });
-      }
-
-      // Add a Fix-It containing the conditional extension text itself.
-      auto insertionLoc = nominal->getBraces().End;
-      note.fixItInsertAfter(
-          insertionLoc,
-          ("\n\nextension " + nominal->getName().str() + ": "
-           + (isUnchecked? "@unchecked " : "") + "Sendable where " +
-           whereClause + " { }\n").str());
-    } else {
-      addSendableFixIt(nominal, note, isUnchecked);
+    // If we can only make the type Sendable via @unchecked, don't provide a Fix-It.
+    if (!isUnchecked) {
+      auto note = nominal->diagnose(diag::add_nominal_sendable_conformance, nominal);
+      if (canMakeSendable && !requirements.empty()) {
+        // Produce a Fix-It containing a conditional conformance to Sendable,
+        // based on the requirements harvested from instance storage.
+
+        // Form the where clause containing all of the requirements.
+        SmallString<64> whereClause;
+        {
+          llvm::raw_svector_ostream out(whereClause);
+          llvm::interleaveComma(
+              requirements, out,
+              [&](const Requirement &req) {
+                out << req.getFirstType().getString() << ": "
+                    << req.getSecondType().getString();
+              });
+        }
+
+        // Add a Fix-It containing the conditional extension text itself.
+        auto insertionLoc = nominal->getBraces().End;
+        note.fixItInsertAfter(
+            insertionLoc,
+            ("\n\nextension " + nominal->getName().str() + ": "
+             + "Sendable where " + whereClause + " { }\n").str());
+      } else {
+        addSendableFixIt(nominal, note, isUnchecked);
+      }
     }
   }
 
@@ -1507,11 +1541,11 @@ void swift::tryDiagnoseExecutorConformance(ASTContext &C,
     canRemoveOldDecls = true;
   } else {
     // Check if the availability of nominal is high enough to be using the ExecutorJob version
-    AvailabilityRange requirementInfo =
-        AvailabilityInference::availableRange(moveOnlyEnqueueRequirement);
-    AvailabilityRange declInfo =
-        AvailabilityContext::forDeclSignature(nominal).getPlatformRange();
-    canRemoveOldDecls = declInfo.isContainedIn(requirementInfo);
+    auto requirementAvailability =
+        AvailabilityContext::forDeclSignature(moveOnlyEnqueueRequirement);
+    auto nominalAvailability = AvailabilityContext::forDeclSignature(nominal);
+    canRemoveOldDecls =
+        nominalAvailability.isContainedIn(requirementAvailability);
   }
 
   auto concurrencyModule = C.getLoadedModule(C.Id_Concurrency);
@@ -1777,7 +1811,7 @@ static bool wasLegacyEscapingUseRestriction(AbstractFunctionDecl *fn) {
   return !(fn->hasAsync()); // basic case: not async = had restriction.
 }
 
-/// Note that while a direct access to the actor isolated property is not legal
+/// Note that while a direct access to the actor-isolated property is not legal
 /// you may want to consider introducing an accessing method for a mutation.
 static void
 maybeNoteMutatingMethodSuggestion(ASTContext &C,
@@ -1853,7 +1887,7 @@ static void noteIsolatedActorMember(ValueDecl const *decl,
     if (*useKind == VarRefUseEnv::Read)
       decl->diagnose(diag::kind_declared_here, decl->getDescriptiveKind());
     else
-      decl->diagnose(diag::actor_mutable_state, decl->getDescriptiveKind());
+      decl->diagnose(diag::actor_mutable_state, decl);
 
   } else {
     decl->diagnose(diag::kind_declared_here, decl->getDescriptiveKind());
@@ -2284,12 +2318,6 @@ static bool safeToDropGlobalActor(
   if (otherIsolation.isErased())
     return true;
 
-  // We currently allow unconditional dropping of global actors from
-  // async function types, despite this confusing Sendable checking
-  // in light of SE-338.
-  if (funcTy->isAsync())
-    return true;
-
   // If the argument is passed over an isolation boundary, it's not
   // safe to erase actor isolation, because the callee can call the
   // function synchronously from outside the isolation domain.
@@ -2536,9 +2564,9 @@ namespace {
       if (result != mutableLocalVarParent.end()) {
         MutableVarParent parent = result->second;
         assert(!parent.isNull());
-        if (parent.is<LoadExpr*>())
+        if (isa<LoadExpr *>(parent))
           return VarRefUseEnv::Read;
-        else if (parent.is<AssignExpr*>())
+        else if (isa<AssignExpr *>(parent))
           return VarRefUseEnv::Mutating;
         else if (auto inout = parent.dyn_cast<InOutExpr*>())
           return inout->isImplicit() ? VarRefUseEnv::Mutating
@@ -2560,7 +2588,8 @@ namespace {
     /// Determine whether code in the given use context might execute
     /// concurrently with code in the definition context.
     bool mayExecuteConcurrentlyWith(
-        const DeclContext *useContext, const DeclContext *defContext);
+        const DeclContext *useContext, const DeclContext *defContext,
+        bool includeSending = false);
 
     /// If the subexpression is a reference to a mutable local variable from a
     /// different context, record its parent. We'll query this as part of
@@ -2637,9 +2666,11 @@ namespace {
 
     /// Some function conversions synthesized by the constraint solver may not
     /// be correct AND the solver doesn't know, so we must emit a diagnostic.
-    void checkFunctionConversion(Expr *funcConv, Type fromType, Type toType) {
+    void checkFunctionConversion(ImplicitConversionExpr *funcConv,
+                                 Type fromType, Type toType) {
       auto diagnoseNonSendableParametersAndResult =
-          [&](FunctionType *fnType, bool downgradeToWarning = false) {
+          [&](FunctionType *fnType,
+              std::optional<unsigned> warnUntilSwiftMode = std::nullopt) {
             auto *dc = getDeclContext();
             llvm::SmallPtrSet<Type, 2> nonSendableTypes;
 
@@ -2669,8 +2700,8 @@ namespace {
                     diag::invalid_function_conversion_with_non_sendable,
                     fromType, toType);
 
-                if (downgradeToWarning)
-                  diag.warnUntilSwiftVersion(7);
+                if (warnUntilSwiftMode)
+                  diag.warnUntilSwiftVersion(*warnUntilSwiftMode);
               }
 
               for (auto type : nonSendableTypes) {
@@ -2687,23 +2718,42 @@ namespace {
           auto toIsolation = toFnType->getIsolation();
 
           if (auto fromActor = fromFnType->getGlobalActor()) {
-            if (toFnType->hasGlobalActor() ||
-                (toFnType->isAsync() && !toIsolation.isNonIsolatedCaller()))
-              return;
+            if (!toFnType->hasGlobalActor()) {
+              auto dc = const_cast<DeclContext *>(getDeclContext());
+              // If it's unsafe to drop global actor attribute:
+              //  - for Sendable types we are going to perform Sendability
+              //    checking of parameters/result.
+              //  - for non-Sendable types we either leave it to region-based
+              //    isolation to determine whether it's okay or not or
+              //    diagnose if types are not-async.
+              if (safeToDropGlobalActor(dc, fromActor, toType,
+                                        getImmediateApply())) {
+                return;
+              }
 
-            auto dc = const_cast<DeclContext*>(getDeclContext());
-            if (!safeToDropGlobalActor(dc, fromActor, toType,
-                                       getImmediateApply())) {
-              // otherwise, it's not a safe cast.
-              ctx.Diags
-                  .diagnose(funcConv->getLoc(),
-                            diag::converting_func_loses_global_actor, fromType,
-                            toType, fromActor)
-                  .warnUntilSwiftVersion(6);
-              return;
+              if (!toFnType->isAsync()) {
+                ctx.Diags
+                    .diagnose(funcConv->getLoc(),
+                              diag::converting_func_loses_global_actor,
+                              fromType, toType, fromActor)
+                    .warnUntilSwiftVersion(6);
+                return;
+              }
             }
           }
 
+          // @isolated(any) functions (async or not) cannot be converted to
+          // synchronous, non-@isolated(any) functions.
+          if (fromIsolation.isErased() && !toIsolation.isErased() &&
+              !toFnType->isAsync()) {
+            ctx.Diags
+                .diagnose(funcConv->getLoc(),
+                          diag::isolated_any_conversion_to_synchronous_func,
+                          fromFnType, toFnType)
+                .warnUntilFutureSwiftVersion();
+            return;
+          }
+
           // Conversions from non-Sendable types are handled by
           // region-based isolation.
           // Function conversions are used to inject concurrency attributes
@@ -2713,16 +2763,28 @@ namespace {
             return;
 
           switch (toIsolation.getKind()) {
-          // Converting to `@execution(caller)` function type
-          case FunctionTypeIsolation::Kind::NonIsolatedCaller: {
+          // Converting to `nonisolated(nonsending)` function type
+          case FunctionTypeIsolation::Kind::NonIsolatedNonsending: {
             switch (fromIsolation.getKind()) {
             case FunctionTypeIsolation::Kind::NonIsolated: {
-              // nonisolated -> @execution(caller) doesn't cross
+              // nonisolated -> nonisolated(nonsending) doesn't cross
               // an isolation boundary.
               if (!fromFnType->isAsync())
                 break;
 
-              // @execution(concurrent) -> @execution(caller)
+              // Applying `nonisolated(nonsending)` to an interface type
+              // of a declaration.
+              if (auto *declRef =
+                      dyn_cast<DeclRefExpr>(funcConv->getSubExpr())) {
+                auto *decl = declRef->getDecl();
+                if (auto *nonisolatedAttr =
+                        decl->getAttrs().getAttribute<NonisolatedAttr>()) {
+                  if (nonisolatedAttr->isNonSending())
+                    return;
+                }
+              }
+
+              // @concurrent -> nonisolated(nonsending)
               // crosses an isolation boundary.
               LLVM_FALLTHROUGH;
             }
@@ -2731,42 +2793,41 @@ namespace {
               diagnoseNonSendableParametersAndResult(toFnType);
               break;
 
+            // @Sendable nonisolated(nonsending) -> nonisolated(nonsending)
+            // doesn't require Sendable checking.
+            case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
+              break;
+
             case FunctionTypeIsolation::Kind::Parameter:
               llvm_unreachable("invalid conversion");
-
-            case FunctionTypeIsolation::Kind::NonIsolatedCaller:
-              // Non isolated caller is always async. This can only occur if we
-              // are converting from an `@Sendable` representation to something
-              // else. So we need to just check that we diagnose non sendable
-              // parameters and results.
-              diagnoseNonSendableParametersAndResult(toFnType);
-              break;
             }
             break;
           }
 
-          // Converting to nonisolated synchronous or @execution(concurrent)
-          // asynchronous function type could require crossing an isolation
-          // boundary.
+          // Converting to nonisolated synchronous or @concurrent
+          // asynchronous function type could require crossing an
+          // isolation boundary.
           case FunctionTypeIsolation::Kind::NonIsolated: {
             switch (fromIsolation.getKind()) {
             case FunctionTypeIsolation::Kind::Parameter:
-            case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+            case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
             case FunctionTypeIsolation::Kind::Erased:
               diagnoseNonSendableParametersAndResult(
-                  toFnType, /*downgradeToWarning=*/true);
+                  toFnType, version::Version::getFutureMajorLanguageVersion());
               break;
 
             case FunctionTypeIsolation::Kind::GlobalActor: {
-              // Handled above by `safeToDropGlobalActor` check.
+              diagnoseNonSendableParametersAndResult(toFnType,
+                                                     /*warnUntilSwiftMode*/ 6);
               break;
             }
 
             case FunctionTypeIsolation::Kind::NonIsolated: {
-              // nonisolated synchronous <-> @execution(concurrent)
+              // nonisolated synchronous <-> @concurrent
               if (fromFnType->isAsync() != toFnType->isAsync()) {
                 diagnoseNonSendableParametersAndResult(
-                    toFnType, /*downgradeToWarning=*/true);
+                    toFnType,
+                    version::Version::getFutureMajorLanguageVersion());
               }
               break;
             }
@@ -2781,17 +2842,18 @@ namespace {
             case FunctionTypeIsolation::Kind::Parameter:
             case FunctionTypeIsolation::Kind::Erased:
               diagnoseNonSendableParametersAndResult(
-                  toFnType, /*downgradeToWarning=*/true);
+                  toFnType, version::Version::getFutureMajorLanguageVersion());
               break;
 
             case FunctionTypeIsolation::Kind::NonIsolated: {
-              // Since @execution(concurrent) as an asynchronous
-              // function it would mean that without Sendable
-              // check it would be possible for non-Sendable state
-              // to escape from actor isolation.
+              // Since @concurrent as an asynchronous function it
+              // would mean that without Sendable check it would
+              // be possible for non-Sendable state to escape from
+              // actor isolation.
               if (fromFnType->isAsync()) {
                 diagnoseNonSendableParametersAndResult(
-                  toFnType, /*downgradeToWarning=*/true);
+                    toFnType,
+                    version::Version::getFutureMajorLanguageVersion());
                 break;
               }
               // Runs on the actor.
@@ -2799,11 +2861,21 @@ namespace {
             }
 
             // Runs on the actor.
-            case FunctionTypeIsolation::Kind::NonIsolatedCaller:
+            case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
               break;
 
             case FunctionTypeIsolation::Kind::GlobalActor:
-              llvm_unreachable("invalid conversion");
+              // If the isolation is the same it means that conversion
+              // covers loss of `@Sendable` or some other attribute and
+              // we don't need Sendable checking because there is no
+              // boundary crossing here.
+              if (fromIsolation.getGlobalActorType()->isEqual(
+                      toIsolation.getGlobalActorType()))
+                break;
+
+              diagnoseNonSendableParametersAndResult(
+                  toFnType, version::Version::getFutureMajorLanguageVersion());
+              break;
             }
             break;
           }
@@ -2821,6 +2893,29 @@ namespace {
       }
     }
 
+    /// Function object that refines isolation for each actor isolation it is
+    /// given, returning true if all of the provided isolations have been
+    /// accounted for, or false if the caller should handle them.
+    class RefineConformances {
+      ActorIsolationChecker &self;
+
+    public:
+      RefineConformances(ActorIsolationChecker &self) : self(self) { }
+
+      bool operator()(ArrayRef<ActorIsolation> isolations) const {
+        bool anyRefined = false;
+        bool anyUnrefined = false;
+        for (const auto &isolation : isolations) {
+          if (self.refineRequiredIsolation(isolation))
+            anyRefined = true;
+          else
+            anyUnrefined = true;
+        }
+
+        return anyRefined && !anyUnrefined;
+      }
+    };
+
     bool refineRequiredIsolation(ActorIsolation refinedIsolation) {
       if (requiredIsolationLoc.isInvalid())
         return false;
@@ -2925,8 +3020,10 @@ namespace {
       auto *explicitClosure = dyn_cast_or_null<ClosureExpr>(closure);
 
       bool preconcurrency = false;
-      if (explicitClosure) {
-        preconcurrency = explicitClosure->isIsolatedByPreconcurrency();
+      if (closure) {
+        preconcurrency =
+            getActorIsolationOfContext(closure, getClosureActorIsolation)
+                .preconcurrency();
       }
 
       for (const auto &capture : localFunc.getCaptureInfo().getCaptures()) {
@@ -2956,13 +3053,13 @@ namespace {
         // If the closure won't execute concurrently with the context in
         // which the declaration occurred, it's okay.
         auto decl = capture.getDecl();
-        auto isolation = getActorIsolation(decl);
 
         // 'nonisolated' local variables are always okay to capture in
         // 'Sendable' closures because they can be accessed from anywhere.
         // Note that only 'nonisolated(unsafe)' can be applied to local
         // variables.
-        if (isolation.isNonisolated())
+        if (isa<VarDecl>(decl) &&
+            getActorIsolation(decl).isNonisolated())
           continue;
 
         auto *context = localFunc.getAsDeclContext();
@@ -2974,12 +3071,6 @@ namespace {
             ->mapTypeIntoContext(decl->getInterfaceType())
             ->getReferenceStorageReferent();
 
-        // Pack expansions are okay to capture as long as the pattern
-        // type is Sendable.
-        if (auto *expansion = type->getAs<PackExpansionType>()) {
-          type = expansion->getPatternType();
-        }
-
         if (type->hasError())
           continue;
 
@@ -2990,7 +3081,7 @@ namespace {
           auto *patternBindingDecl = getTopPatternBindingDecl();
           if (patternBindingDecl && patternBindingDecl->isAsyncLet()) {
             // Defer diagnosing checking of non-Sendable types that are passed
-            // into async let to SIL level region based isolation.
+            // into async let to SIL level region-based isolation.
             return;
           }
 
@@ -3018,38 +3109,26 @@ namespace {
         }
       }
 
-      // FIXME: When passing to a sending parameter, should this be handled
-      // by region isolation? Or should it always be handled by region
-      // isolation?
-      if (ctx.LangOpts.hasFeature(Feature::IsolatedConformances) &&
-          (mayExecuteConcurrentlyWith(
-              localFunc.getAsDeclContext(), getDeclContext()) ||
-           (explicitClosure && explicitClosure->isPassedToSendingParameter()))) {
-        GenericSignature genericSig;
-        if (auto afd = localFunc.getAbstractFunctionDecl())
-          genericSig = afd->getGenericSignature();
-
+      if (ctx.LangOpts.hasFeature(Feature::RegionBasedIsolation) &&
+          mayExecuteConcurrentlyWith(
+              localFunc.getAsDeclContext(), getDeclContext(),
+              /*includeSending*/true)) {
         for (const auto &capturedType :
                  localFunc.getCaptureInfo().getCapturedTypes()) {
-          unsigned genericDepth;
           Type type = capturedType.getType();
           if (auto archetype = type->getAs<ArchetypeType>()) {
-            genericDepth = archetype->getInterfaceType()->getRootGenericParam()
-                ->getDepth();
-          } else if (type->isTypeParameter()) {
-            genericDepth = type->getRootGenericParam()->getDepth();
-
-            type = localFunc.getAsDeclContext()->mapTypeIntoContext(type);
+            // If the generic signature of the environment prohibits this
+            // type to have an isolated conformance, there is nothing to
+            // diagnose.
+            Type interfaceType = archetype->getInterfaceType();
+            auto genericEnv = archetype->getGenericEnvironment();
+            auto genericSig = genericEnv->getGenericSignature();
+            if (genericSig->prohibitsIsolatedConformance(interfaceType))
+              continue;
           } else {
             continue;
           }
 
-          // If the local function is generic and this is one of its generic
-          // parameters, ignore it.
-          if (genericSig.getNextDepth() > 0 &&
-              genericDepth < genericSig.getNextDepth() - 1)
-            continue;
-
           // Check that the metatype is sendable.
           SendableCheckContext sendableContext(getDeclContext(), preconcurrency);
           diagnoseNonSendableTypes(MetatypeType::get(type),
@@ -3144,6 +3223,65 @@ namespace {
       return LazyInitializerWalking::InAccessor;
     }
 
+    /// This function is a stripped down version of checkApply that only is
+    /// applied to curry thunks generated by the type checker that explicitly
+    /// have isolation put upon them by the typechecker to work around a bug in
+    /// 6.2. We do not perform any sort of actual inference... we only use it to
+    /// mark the apply as being isolation crossing if we have an autoclosure
+    /// with mismatching isolation.
+    ///
+    /// We take advantage that we only can have two types of isolation on such
+    /// an autoclosure, global actor isolation and nonisolated(nonsending).
+    ///
+    /// For more information, see the comment in buildSingleCurryThunk.
+    void perform62AutoclosureCurryThunkChecking(ApplyExpr *apply,
+                                                AutoClosureExpr *fn) {
+      // The isolation of the context that we are in.
+      std::optional<ActorIsolation> contextIsolation;
+      auto getContextIsolation = [&]() -> ActorIsolation {
+        if (contextIsolation)
+          return *contextIsolation;
+
+        auto declContext = const_cast<DeclContext *>(getDeclContext());
+        contextIsolation =
+            getInnermostIsolatedContext(declContext, getClosureActorIsolation);
+        return *contextIsolation;
+      };
+
+      std::optional<ActorIsolation> unsatisfiedIsolation;
+
+      // NOTE: Normally autoclosures did not have ActorIsolation set on it since
+      // we do not visit the function of the partial apply due to a bug. The
+      // only reason why it is set is b/c we are explicitly setting this in the
+      // type checker when we generate the single and double curry thunks.
+      auto fnTypeIsolation = fn->getActorIsolation();
+      if (fnTypeIsolation.isGlobalActor()) {
+        Type globalActor = fnTypeIsolation.getGlobalActor();
+        if (!(getContextIsolation().isGlobalActor() &&
+              getContextIsolation().getGlobalActor()->isEqual(globalActor)))
+          unsatisfiedIsolation = ActorIsolation::forGlobalActor(globalActor);
+      }
+
+      // If there was no unsatisfied actor isolation, we're done.
+      if (!unsatisfiedIsolation)
+        return;
+
+      // Record whether the callee isolation or the context isolation
+      // is preconcurrency, which is used later to downgrade errors to
+      // warnings in minimal checking.
+      auto calleeDecl = apply->getCalledValue(/*skipFunctionConversions=*/true);
+      bool preconcurrency =
+          getContextIsolation().preconcurrency() ||
+          (calleeDecl && getActorIsolation(calleeDecl).preconcurrency());
+      unsatisfiedIsolation =
+          unsatisfiedIsolation->withPreconcurrency(preconcurrency);
+
+      // At this point, we know a jump is made to the callee that yields
+      // an isolation requirement unsatisfied by the calling context, so
+      // set the unsatisfiedIsolationJump fields of the ApplyExpr appropriately
+      apply->setIsolationCrossing(getContextIsolation(), *unsatisfiedIsolation);
+    }
+
     PreWalkResult<Pattern *> walkToPatternPre(Pattern *pattern) override {
       // Walking into patterns leads to nothing good because then we
       // end up visiting the AccessorDecls of a top-level
@@ -3202,7 +3340,22 @@ namespace {
       }
 
       if (auto *closure = dyn_cast<AbstractClosureExpr>(expr)) {
-        closure->setActorIsolation(determineClosureIsolation(closure));
+        auto isolation = determineClosureIsolation(closure);
+        closure->setActorIsolation(isolation);
+
+        // There is a case in which the constraint solver cannot decide
+        // that a closure is `nonisolated(nonsending)` because it cannot
+        // analyze the captures, but the closure isolation logic can.
+        // Rewrite the closure type at this point.
+        if (isolation.isCallerIsolationInheriting()) {
+          auto fnType = closure->getType()->castTo<AnyFunctionType>();
+          if (!fnType->getIsolation().isNonIsolatedCaller()) {
+            fnType = fnType->withIsolation(
+              FunctionTypeIsolation::forNonIsolatedCaller());
+            closure->setType(fnType);
+          }
+        }
+
         checkLocalCaptures(closure);
         contextStack.push_back(closure);
         return Action::Continue(expr);
@@ -3261,6 +3414,19 @@ namespace {
 
             partialApply->base->walk(*this);
 
+            // See if we have an autoclosure as our function. If so, check if we
+            // have a difference in isolation. If so, make this apply an
+            // isolation crossing apply.
+            //
+            // NOTE: This is just a work around for 6.2 to make checking of
+            // double curry thunks work correctly in the face of us not
+            // performing full type checking of autoclosures that are functions
+            // of the apply. We are doing this to make sure that we do not
+            // increase the surface area too much.
+            if (auto *fn = dyn_cast<AutoClosureExpr>(apply->getFn())) {
+              perform62AutoclosureCurryThunkChecking(apply, fn);
+            }
+
             return Action::SkipNode(expr);
           }
         }
@@ -3304,19 +3470,6 @@ namespace {
         }
       }
 
-      // The constraint solver may not have chosen legal casts.
-      if (auto funcConv = dyn_cast<FunctionConversionExpr>(expr)) {
-        checkFunctionConversion(funcConv,
-                                funcConv->getSubExpr()->getType(),
-                                funcConv->getType());
-      }
-
-      if (auto *isolationErasure = dyn_cast<ActorIsolationErasureExpr>(expr)) {
-        checkFunctionConversion(isolationErasure,
-                                isolationErasure->getSubExpr()->getType(),
-                                isolationErasure->getType());
-      }
-
       if (auto *defaultArg = dyn_cast<DefaultArgumentExpr>(expr)) {
         checkDefaultArgument(defaultArg);
       }
@@ -3324,13 +3477,20 @@ namespace {
       if (auto erasureExpr = dyn_cast<ErasureExpr>(expr)) {
         checkIsolatedConformancesInContext(
             erasureExpr->getConformances(), erasureExpr->getLoc(),
-            getDeclContext());
+            getDeclContext(), RefineConformances{*this});
       }
 
       if (auto *underlyingToOpaque = dyn_cast<UnderlyingToOpaqueExpr>(expr)) {
         checkIsolatedConformancesInContext(
             underlyingToOpaque->substitutions, underlyingToOpaque->getLoc(),
-            getDeclContext());
+            getDeclContext(), RefineConformances{*this});
+      }
+
+      if (auto *collectionExpr = dyn_cast<CollectionExpr>(expr)) {
+        checkIsolatedConformancesInContext(
+            collectionExpr->getInitializer(),
+            collectionExpr->getLoc(),
+            getDeclContext(), RefineConformances{*this});
       }
 
       return Action::Continue(expr);
@@ -3349,7 +3509,7 @@ namespace {
       }
 
       if (auto *apply = dyn_cast<ApplyExpr>(expr)) {
-        assert(applyStack.back().get<ApplyExpr *>() == apply);
+        assert(cast<ApplyExpr *>(applyStack.back()) == apply);
         applyStack.pop_back();
       }
 
@@ -3379,6 +3539,41 @@ namespace {
       if (auto isolationExpr = dyn_cast<CurrentContextIsolationExpr>(expr))
         recordCurrentContextIsolation(isolationExpr);
 
+      // `withoutActuallyEscaping` parameter types are set to be
+      // `nonisolated(nonsending)` when the `NonisolatedNonsendingByDefault`
+      // feature is enabled, which means that we need to make the argument
+      // as `nonisolated(nonsending)` if it's a closure. This cannot be done
+      // sooner because we need to make sure that closure is definitely
+      // nonisolated and due to how AST is structured we cannot do this in
+      // `determineClosureIsolation`.
+      if (ctx.LangOpts.hasFeature(Feature::NonisolatedNonsendingByDefault)) {
+        if (auto *MTEE = dyn_cast<MakeTemporarilyEscapableExpr>(expr)) {
+          if (auto *call = dyn_cast<CallExpr>(MTEE->getSubExpr())) {
+            if (auto *closure = dyn_cast<ClosureExpr>(call->getFn())) {
+              if (auto closureTy = closure->getType()->getAs<FunctionType>()) {
+                if (closureTy->isAsync() &&
+                    closure->getActorIsolation().isNonisolated())
+                  closure->setActorIsolation(
+                      ActorIsolation::forCallerIsolationInheriting());
+              }
+            }
+          }
+        }
+      }
+
+      // The constraint solver may not have chosen legal casts.
+      if (auto funcConv = dyn_cast<FunctionConversionExpr>(expr)) {
+        checkFunctionConversion(funcConv,
+                                funcConv->getSubExpr()->getType(),
+                                funcConv->getType());
+      }
+
+      if (auto *isolationErasure = dyn_cast<ActorIsolationErasureExpr>(expr)) {
+        checkFunctionConversion(isolationErasure,
+                                isolationErasure->getSubExpr()->getType(),
+                                isolationErasure->getType());
+      }
+
       return Action::Continue(expr);
     }
 
@@ -3402,12 +3597,14 @@ namespace {
             if (isolation == ActorIsolation::ActorInstance) {
               VarDecl *var = isolation.getActorInstance();
               if (!var) {
+                assert(!isolation.isActorInstanceForCapture() &&
+                       "capture isolation without a variable reference?");
                 auto dc = const_cast<DeclContext *>(getDeclContext());
-                auto paramIdx = isolation.getActorInstanceParameter();
-                if (paramIdx == 0) {
+                if (isolation.isActorInstanceForSelfParameter()) {
                   var = cast<AbstractFunctionDecl>(dc)->getImplicitSelfDecl();
                 } else {
-                  var = const_cast<ParamDecl *>(getParameterAt(dc, paramIdx - 1));
+                  auto paramIdx = isolation.getActorInstanceParameterIndex();
+                  var = const_cast<ParamDecl *>(getParameterAt(dc, paramIdx));
                 }
               }
               return var;
@@ -3663,7 +3860,7 @@ namespace {
           return;
 
         if (isPartialApply) {
-          auto *apply = call.get<ApplyExpr *>();
+          auto *apply = cast<ApplyExpr *>(call);
           // The partially applied InoutArg is a property of actor. This
           // can really only happen when the property is a struct with a
           // mutating async method.
@@ -3684,7 +3881,7 @@ namespace {
         if (auto *apply = call.dyn_cast<ApplyExpr *>()) {
           isImplicitlyAsync = apply->isImplicitlyAsync().has_value();
         } else {
-          auto *lookup = call.get<LookupExpr *>();
+          auto *lookup = cast<LookupExpr *>(call);
           isImplicitlyAsync = lookup->isImplicitlyAsync().has_value();
         }
 
@@ -3887,6 +4084,10 @@ namespace {
       Expr *argForIsolatedParam = nullptr;
       auto calleeDecl = apply->getCalledValue(/*skipFunctionConversions=*/true);
 
+      if (calleeDecl &&
+          calleeDecl->getAttrs().hasAttribute<UnsafeInheritExecutorAttr>())
+        return false;
+
       auto fnTypeIsolation = fnType->getIsolation();
       if (fnTypeIsolation.isGlobalActor()) {
         // If the function type is global-actor-qualified, determine whether
@@ -3932,10 +4133,6 @@ namespace {
           calleeDecl = memberRef->first.getDecl();
           argForIsolatedParam = selfApplyFn->getBase();
         }
-      } else if (calleeDecl &&
-                 calleeDecl->getAttrs()
-                     .hasAttribute<UnsafeInheritExecutorAttr>()) {
-        return false;
       }
 
       // Check for isolated parameters.
@@ -3986,11 +4183,25 @@ namespace {
         break;
       }
 
-      // If we're calling an async function that's nonisolated, and we're in
-      // an isolated context, then we're exiting the actor context.
-      if (mayExitToNonisolated && fnType->isAsync() &&
-          getContextIsolation().isActorIsolated())
-        unsatisfiedIsolation = ActorIsolation::forNonisolated(/*unsafe=*/false);
+      // If we're calling an async function that's nonisolated, and we're in an
+      // isolated context, then we're exiting the actor context unless we have
+      // nonisolated(nonsending) isolation.
+      //
+      // NOTE: We do not check fnTypeIsolation since that is the AST level
+      // actual isolation which does not have nonisolated(nonsending) added to
+      // it yet. Instead, we want the direct callee including casts since those
+      // casts is what would add the nonisolated(nonsending) bit to the function
+      // type isolation.
+      if (mayExitToNonisolated && fnType->isAsync()) {
+        if (getContextIsolation().isActorIsolated() &&
+            !fnTypeIsolation.isNonIsolatedCaller())
+          unsatisfiedIsolation =
+              ActorIsolation::forNonisolated(/*unsafe=*/false);
+        else if (getContextIsolation().isCallerIsolationInheriting() &&
+                 fnTypeIsolation.isNonIsolated())
+          unsatisfiedIsolation =
+              ActorIsolation::forNonisolated(/*unsafe=*/false);
+      }
 
       // If there was no unsatisfied actor isolation, we're done.
       if (!unsatisfiedIsolation)
@@ -4042,11 +4253,10 @@ namespace {
 
           applyErrors[key].push_back(mismatch);
         } else {
-          ctx.Diags.diagnose(
-            apply->getLoc(),
-            diagnostic.getID(),
-            diagnostic.getArgs())
-              .warnUntilSwiftVersionIf(preconcurrency, 6);
+          ctx.Diags
+              .diagnose(apply->getLoc(), diagnostic.getID(),
+                        diagnostic.getArgs())
+              .limitBehaviorIf(preconcurrency, DiagnosticBehavior::Warning);
 
           if (calleeDecl) {
             auto calleeIsolation = getInferredActorIsolation(calleeDecl);
@@ -4179,11 +4389,10 @@ namespace {
         const VarDecl *var = isolation.getActorInstance();
         if (!var) {
           auto dc = getDeclContext();
-          auto paramIdx = isolation.getActorInstanceParameter();
-          if (paramIdx == 0) {
+          if (isolation.isActorInstanceForSelfParameter()) {
             var = cast<AbstractFunctionDecl>(dc)->getImplicitSelfDecl();
           } else {
-            var = getParameterAt(dc, paramIdx - 1);
+            var = getParameterAt(dc, isolation.getActorInstanceParameterIndex());
           }
         }
         actorExpr = new (ctx) DeclRefExpr(
@@ -4214,10 +4423,15 @@ namespace {
 
       case ActorIsolation::Unspecified:
       case ActorIsolation::Nonisolated:
-      case ActorIsolation::CallerIsolationInheriting:
       case ActorIsolation::NonisolatedUnsafe:
         actorExpr = new (ctx) NilLiteralExpr(loc, /*implicit=*/false);
         break;
+      case ActorIsolation::CallerIsolationInheriting:
+        // For caller isolation this expression will be replaced in SILGen
+        // because we're adding an implicit isolated parameter that #isolated
+        // must resolve to, but cannot do so during AST expansion quite yet.
+        actorExpr = new (ctx) NilLiteralExpr(loc, /*implicit=*/false);
+        break;
       }
 
 
@@ -4386,9 +4600,10 @@ namespace {
               break;
             }
 
-            bool downgrade = isolation.isGlobalActor() ||
-              options.contains(
-                  ActorReferenceResult::Flags::Preconcurrency);
+            bool downgrade =
+                isolation.isGlobalActor() ||
+                options.contains(
+                    ActorReferenceResult::Flags::CompatibilityDowngrade);
 
             ctx.Diags.diagnose(
                 component.getLoc(), diag::actor_isolated_keypath_component,
@@ -4439,7 +4654,8 @@ namespace {
         return false;
 
       // Make sure isolated conformances are formed in the right context.
-      checkIsolatedConformancesInContext(declRef, loc, getDeclContext());
+      checkIsolatedConformancesInContext(declRef, loc, getDeclContext(),
+                                         RefineConformances{*this});
 
       auto *const decl = declRef.getDecl();
 
@@ -4492,7 +4708,7 @@ namespace {
       if (!partialApply &&
           (result.isolation.isGlobalActor() ||
            (result.isolation == ActorIsolation::ActorInstance &&
-            result.isolation.getActorInstanceParameter() > 0)) &&
+            !result.isolation.isActorInstanceForSelfParameter())) &&
           isa<AbstractFunctionDecl>(decl))
         return false;
 
@@ -4577,6 +4793,10 @@ namespace {
         // Does the reference originate from a @preconcurrency context?
         bool preconcurrencyContext =
           result.options.contains(ActorReferenceResult::Flags::Preconcurrency);
+        bool shouldDowngradeToWarning =
+            preconcurrencyContext ||
+            result.options.contains(
+                ActorReferenceResult::Flags::CompatibilityDowngrade);
 
         Type derivedConformanceType;
         DeclName requirementName;
@@ -4611,21 +4831,26 @@ namespace {
             refErrors.insert(std::make_pair(keyPair, list));
           }
         } else {
-          ctx.Diags.diagnose(
-              loc, diag::actor_isolated_non_self_reference,
-              decl, useKind,
-              refKind + 1, refGlobalActor,
-              result.isolation)
-          .warnUntilSwiftVersionIf(preconcurrencyContext, 6);
-          maybeNoteMutatingMethodSuggestion(ctx, decl, loc, getDeclContext(), result.isolation,
-                                            kindOfUsage(decl, context).value_or(VarRefUseEnv::Read));
+          {
+            auto diagnostic = ctx.Diags.diagnose(
+                loc, diag::actor_isolated_non_self_reference, decl, useKind,
+                refKind + 1, refGlobalActor, result.isolation);
+
+            // For compatibility downgrades - the error is downgraded until
+            // Swift 6, for preconcurrency - always.
+            if (shouldDowngradeToWarning)
+              diagnostic.limitBehaviorWithPreconcurrency(
+                  DiagnosticBehavior::Warning, preconcurrencyContext);
+          }
+
+          maybeNoteMutatingMethodSuggestion(
+              ctx, decl, loc, getDeclContext(), result.isolation,
+              kindOfUsage(decl, context).value_or(VarRefUseEnv::Read));
 
           if (derivedConformanceType) {
             auto *decl = dyn_cast<ValueDecl>(getDeclContext()->getAsDecl());
-            ctx.Diags.diagnose(loc, diag::in_derived_witness,
-                               decl->getDescriptiveKind(),
-                               requirementName,
-                               derivedConformanceType);
+            ctx.Diags.diagnose(loc, diag::in_derived_witness, decl,
+                               requirementName, derivedConformanceType);
           }
 
           noteIsolatedActorMember(decl, context);
@@ -4668,6 +4893,70 @@ namespace {
   };
 } // end anonymous namespace
 
+/// Compute the isolation of a closure or local function from its parent
+/// isolation.
+///
+/// Doesn't apply preconcurrency because it's generally easier for the
+/// caller to do so.
+static ActorIsolation
+computeClosureIsolationFromParent(DeclContext *closure,
+                                  ActorIsolation parentIsolation,
+                                  bool checkIsolatedCapture) {
+  // We must have parent isolation determined to get here.
+  switch (parentIsolation) {
+  case ActorIsolation::CallerIsolationInheriting:
+  case ActorIsolation::Nonisolated:
+  case ActorIsolation::NonisolatedUnsafe:
+  case ActorIsolation::Unspecified:
+    return ActorIsolation::forNonisolated(
+        parentIsolation == ActorIsolation::NonisolatedUnsafe);
+
+  case ActorIsolation::Erased:
+    llvm_unreachable("context cannot have erased isolation");
+
+  case ActorIsolation::GlobalActor:
+    // This should already be an interface type, so we don't need to remap
+    // it between the contexts.
+    return ActorIsolation::forGlobalActor(parentIsolation.getGlobalActor());
+
+  case ActorIsolation::ActorInstance: {
+    // In non-@Sendable local functions, we always inherit the enclosing
+    // isolation, forcing a capture of it if necessary.
+    if (isa<FuncDecl>(closure)) {
+      // We should always have a VarDecl in this case, where we got the
+      // ActorIsolation from a context; the non-VarDecl cases are only used
+      // locally within isolation checking.
+      auto actor = parentIsolation.getActorInstance();
+      assert(actor);
+      return ActorIsolation::forActorInstanceCapture(actor);
+    }
+
+    if (checkIsolatedCapture) {
+      auto closureAsFn = AnyFunctionRef::fromFunctionDeclContext(closure);
+      if (auto param = closureAsFn.getCaptureInfo().getIsolatedParamCapture())
+        return ActorIsolation::forActorInstanceCapture(param);
+
+      auto *explicitClosure = dyn_cast<ClosureExpr>(closure);
+      // @_inheritActorContext(always) forces the isolation capture.
+      if (explicitClosure && explicitClosure->alwaysInheritsActorContext()) {
+        if (parentIsolation.isActorInstanceIsolated()) {
+          if (auto *param = parentIsolation.getActorInstance())
+            return ActorIsolation::forActorInstanceCapture(param);
+        }
+        return parentIsolation;
+      }
+    } else {
+      // If we don't have capture information during code completion, assume
+      // that the closure captures the `isolated` parameter from the parent
+      // context.
+      return parentIsolation;
+    }
+
+    return ActorIsolation::forNonisolated(/*unsafe=*/false);
+  }
+  }
+}
+
 ActorIsolation ActorIsolationChecker::determineClosureIsolation(
     AbstractClosureExpr *closure) const {
   bool preconcurrency = false;
@@ -4687,6 +4976,19 @@ ActorIsolation ActorIsolationChecker::determineClosureIsolation(
           attr && ctx.LangOpts.hasFeature(Feature::ClosureIsolation)) {
         return ActorIsolation::forNonisolated(attr->isUnsafe());
       }
+
+      if (explicitClosure->getAttrs().hasAttribute<ConcurrentAttr>()) {
+        return ActorIsolation::forNonisolated(/*unsafe=*/false);
+      }
+    }
+
+    // `nonisolated(nonsending)` inferred from the context makes
+    // the closure caller isolated.
+    if (auto closureTy = getType(closure)) {
+      if (auto *closureFnTy = closureTy->getAs<FunctionType>()) {
+        if (closureFnTy->getIsolation().isNonIsolatedCaller())
+          return ActorIsolation::forCallerIsolationInheriting();
+      }
     }
 
     // If a closure has an isolated parameter, it is isolated to that
@@ -4696,6 +4998,37 @@ ActorIsolation ActorIsolationChecker::determineClosureIsolation(
         return ActorIsolation::forActorInstanceCapture(param);
     }
 
+    // A non-Sendable closure gets its isolation from its context.
+    auto parentIsolation = getActorIsolationOfContext(
+        closure->getParent(), getClosureActorIsolation);
+    preconcurrency |= parentIsolation.preconcurrency();
+
+    auto normalIsolation = computeClosureIsolationFromParent(
+        closure, parentIsolation, checkIsolatedCapture);
+
+    // The solver has to be conservative and produce a conversion to
+    // `nonisolated(nonsending)` because at solution application time
+    // we don't yet know whether there are any captures which would
+    // make closure isolated.
+    //
+    // At this point we know that closure is not explicitly annotated with
+    // global actor, nonisolated/@concurrent attributes and doesn't have
+    // isolated parameters. If our closure is nonisolated and we have a
+    // conversion to nonisolated(nonsending), then we should respect that.
+    if (auto *explicitClosure = dyn_cast<ClosureExpr>(closure);
+        !normalIsolation.isGlobalActor()) {
+      if (auto *fce =
+              dyn_cast_or_null<FunctionConversionExpr>(Parent.getAsExpr())) {
+        auto expectedIsolation =
+            fce->getType()->castTo<FunctionType>()->getIsolation();
+        if (expectedIsolation.isNonIsolatedCaller()) {
+          auto captureInfo = explicitClosure->getCaptureInfo();
+          if (!captureInfo.getIsolatedParamCapture())
+            return ActorIsolation::forCallerIsolationInheriting();
+        }
+      }
+    }
+
     // If we have a closure that acts as an isolation inference boundary, then
     // we return that it is non-isolated.
     //
@@ -4706,50 +5039,14 @@ ActorIsolation ActorIsolationChecker::determineClosureIsolation(
                                             /*canInheritActorContext=*/true))
       return ActorIsolation::forNonisolated(/*unsafe=*/false);
 
-    // A non-Sendable closure gets its isolation from its context.
-    auto parentIsolation = getActorIsolationOfContext(
-        closure->getParent(), getClosureActorIsolation);
-    preconcurrency |= parentIsolation.preconcurrency();
-
-    // We must have parent isolation determined to get here.
-    switch (parentIsolation) {
-    case ActorIsolation::CallerIsolationInheriting:
-    case ActorIsolation::Nonisolated:
-    case ActorIsolation::NonisolatedUnsafe:
-    case ActorIsolation::Unspecified:
-      return ActorIsolation::forNonisolated(
-          parentIsolation == ActorIsolation::NonisolatedUnsafe);
-
-    case ActorIsolation::Erased:
-      llvm_unreachable("context cannot have erased isolation");
-
-    case ActorIsolation::GlobalActor: {
-      Type globalActor = closure->mapTypeIntoContext(
-          parentIsolation.getGlobalActor()->mapTypeOutOfContext());
-      return ActorIsolation::forGlobalActor(globalActor);
-    }
-
-    case ActorIsolation::ActorInstance: {
-      if (checkIsolatedCapture) {
-        if (auto param = closure->getCaptureInfo().getIsolatedParamCapture())
-          return ActorIsolation::forActorInstanceCapture(param);
-      } else {
-        // If we don't have capture information during code completion, assume
-        // that the closure captures the `isolated` parameter from the parent
-        // context.
-        return parentIsolation;
-      }
-
-      return ActorIsolation::forNonisolated(/*unsafe=*/false);
-    }
-    }
+    return normalIsolation;
   }();
 
   // Apply computed preconcurrency.
   isolation = isolation.withPreconcurrency(preconcurrency);
 
-  if (ctx.LangOpts.getFeatureState(Feature::AsyncCallerExecution)
-          .isEnabledForAdoption()) {
+  if (ctx.LangOpts.getFeatureState(Feature::NonisolatedNonsendingByDefault)
+          .isEnabledForMigration()) {
     warnAboutNewNonisolatedAsyncExecutionBehavior(ctx, closure, isolation);
   }
 
@@ -4757,13 +5054,12 @@ ActorIsolation ActorIsolationChecker::determineClosureIsolation(
 }
 
 bool ActorIsolationChecker::mayExecuteConcurrentlyWith(
-    const DeclContext *useContext, const DeclContext *defContext) {
+    const DeclContext *useContext, const DeclContext *defContext,
+    bool includeSending) {
   // Fast path for when the use and definition contexts are the same.
   if (useContext == defContext)
     return false;
 
-  bool isolatedStateMayEscape = false;
-
   auto useIsolation = getActorIsolationOfContext(
       const_cast<DeclContext *>(useContext), getClosureActorIsolation);
   if (useIsolation.isActorIsolated()) {
@@ -4781,16 +5077,6 @@ bool ActorIsolationChecker::mayExecuteConcurrentlyWith(
     if (ctx.LangOpts.hasFeature(Feature::GlobalActorIsolatedTypesUsability) &&
         regionIsolationEnabled && useIsolation.isGlobalActor())
       return false;
-
-    // If the local function is not Sendable, its isolation differs
-    // from that of the context, and both contexts are actor isolated,
-    // then capturing non-Sendable values allows the closure to stash
-    // those values into actor isolated state. The original context
-    // may also stash those values into isolated state, enabling concurrent
-    // access later on.
-    isolatedStateMayEscape =
-        (!regionIsolationEnabled &&
-        useIsolation.isActorIsolated() && defIsolation.isActorIsolated());
   }
 
   // Walk the context chain from the use to the definition.
@@ -4800,8 +5086,10 @@ bool ActorIsolationChecker::mayExecuteConcurrentlyWith(
       if (closure->isSendable())
         return true;
 
-      if (isolatedStateMayEscape)
-        return true;
+      if (auto *explicitClosure = dyn_cast<ClosureExpr>(closure)) {
+        if (includeSending && explicitClosure->isPassedToSendingParameter())
+          return true;
+      }
     }
 
     if (auto func = dyn_cast<FuncDecl>(useContext)) {
@@ -4809,9 +5097,6 @@ bool ActorIsolationChecker::mayExecuteConcurrentlyWith(
         // If the function is @Sendable... it can be run concurrently.
         if (func->isSendable())
           return true;
-
-        if (isolatedStateMayEscape)
-          return true;
       }
     }
 
@@ -4889,10 +5174,16 @@ getIsolationFromAttributes(const Decl *decl, bool shouldDiagnose = true,
                            bool onlyExplicit = false) {
   // Look up attributes on the declaration that can affect its actor isolation.
   // If any of them are present, use that attribute.
-  auto isolatedAttr = decl->getAttrs().getAttribute<IsolatedAttr>();
+
+  // 'isolated` attribute in the declaration context currently applies
+  // only to `deinit` declarations, invalid uses are going to
+  // be diagnosed as part of attribute checking.
+  auto isolatedAttr = isa<DestructorDecl>(decl)
+                          ? decl->getAttrs().getAttribute<IsolatedAttr>()
+                          : nullptr;
   auto nonisolatedAttr = decl->getAttrs().getAttribute<NonisolatedAttr>();
   auto globalActorAttr = decl->getGlobalActorAttr();
-  auto concurrentExecutionAttr = decl->getAttrs().getAttribute<ExecutionAttr>();
+  auto concurrentAttr = decl->getAttrs().getAttribute<ConcurrentAttr>();
 
   // Remove implicit attributes if we only care about explicit ones.
   if (onlyExplicit) {
@@ -4902,13 +5193,13 @@ getIsolationFromAttributes(const Decl *decl, bool shouldDiagnose = true,
       isolatedAttr = nullptr;
     if (globalActorAttr && globalActorAttr->first->isImplicit())
       globalActorAttr = std::nullopt;
-    if (concurrentExecutionAttr && concurrentExecutionAttr->isImplicit())
-      concurrentExecutionAttr = nullptr;
+    if (concurrentAttr && concurrentAttr->isImplicit())
+      concurrentAttr = nullptr;
   }
 
   unsigned numIsolationAttrs =
       (isolatedAttr ? 1 : 0) + (nonisolatedAttr ? 1 : 0) +
-      (globalActorAttr ? 1 : 0) + (concurrentExecutionAttr ? 1 : 0);
+      (globalActorAttr ? 1 : 0) + (concurrentAttr ? 1 : 0);
   if (numIsolationAttrs == 0) {
     if (isa<DestructorDecl>(decl) && !decl->isImplicit()) {
       return ActorIsolation::forNonisolated(false);
@@ -4916,34 +5207,25 @@ getIsolationFromAttributes(const Decl *decl, bool shouldDiagnose = true,
     return std::nullopt;
   }
 
-  // If the declaration is explicitly marked with 'execution', return the
-  // appropriate isolation.
-  //
-  // NOTE: This needs to occur before we handle an explicit nonisolated attr,
-  // since if @execution and nonisolated are used together, we want to ensure
-  // that @execution takes priority. This ensures that if we import code from a
-  // module that was compiled with a different value for AsyncCallerExecution,
-  // we get the semantics of the source module.
-  if (concurrentExecutionAttr) {
-    switch (concurrentExecutionAttr->getBehavior()) {
-    case ExecutionKind::Concurrent:
-      return ActorIsolation::forNonisolated(false /*is unsafe*/);
-    case ExecutionKind::Caller:
-      return ActorIsolation::forCallerIsolationInheriting();
-    }
-  }
+  if (concurrentAttr)
+    return ActorIsolation::forNonisolated(/*is unsafe*/ false);
 
   // If the declaration is explicitly marked 'nonisolated', report it as
   // independent.
   if (nonisolatedAttr) {
-    // If the nonisolated async inherits isolation from context is set, return
-    // caller isolation inheriting.
+    // 'nonisolated(nonsending)' modifier is set on the decl.
+    if (nonisolatedAttr->isNonSending())
+      return ActorIsolation::forCallerIsolationInheriting();
+
+    // If the nonisolated async inherits isolation from context,
+    // return caller isolation inheriting.
     if (decl->getASTContext().LangOpts.hasFeature(
-            Feature::AsyncCallerExecution)) {
-      if (auto *func = dyn_cast<AbstractFunctionDecl>(decl);
-          func && func->hasAsync() &&
-          func->getModuleContext() == decl->getASTContext().MainModule) {
-        return ActorIsolation::forCallerIsolationInheriting();
+            Feature::NonisolatedNonsendingByDefault)) {
+      if (auto *value = dyn_cast<ValueDecl>(decl)) {
+        if (value->isAsync() &&
+            value->getModuleContext() == decl->getASTContext().MainModule) {
+          return ActorIsolation::forCallerIsolationInheriting();
+        }
       }
     }
 
@@ -4951,16 +5233,15 @@ getIsolationFromAttributes(const Decl *decl, bool shouldDiagnose = true,
   }
 
   // If the declaration is explicitly marked 'isolated', infer actor isolation
-  // from the context. Currently applies only to DestructorDecl
+  // from the context. Currently applies only to DestructorDecl.
   if (isolatedAttr) {
-    assert(isa<DestructorDecl>(decl));
-
     auto dc = decl->getDeclContext();
     auto selfTypeDecl = dc->getSelfNominalTypeDecl();
     std::optional<ActorIsolation> result;
     if (selfTypeDecl) {
       if (selfTypeDecl->isAnyActor()) {
-        result = ActorIsolation::forActorInstanceSelf(selfTypeDecl);
+        result = ActorIsolation::forActorInstanceSelf(
+          const_cast<AbstractFunctionDecl*>(cast<AbstractFunctionDecl>(decl)));
       } else {
         // If the declaration is in an extension that has one of the isolation
         // attributes, use that.
@@ -5038,6 +5319,33 @@ getIsolationFromAttributes(const Decl *decl, bool shouldDiagnose = true,
   llvm_unreachable("Forgot about an attribute?");
 }
 
+/// Determine the default isolation for the given declaration context.
+static DefaultIsolation getDefaultIsolationForContext(const DeclContext *dc) {
+  // Check whether there is a file-specific setting.
+  if (auto *sourceFile = dc->getParentSourceFile()) {
+    if (auto defaultIsolationInFile = sourceFile->getDefaultIsolation())
+      return defaultIsolationInFile.value();
+  }
+
+  // If we're in the main module, check the language option.
+  ASTContext &ctx = dc->getASTContext();
+  if (dc->getParentModule() == ctx.MainModule)
+    return ctx.LangOpts.DefaultIsolationBehavior;
+
+  // Otherwise, default to nonisolated.
+  return DefaultIsolation::Nonisolated;
+}
+
+/// Determines whether explicit 'nonisolated' is different from 'unspecified'
+/// in the given context.
+static bool explicitNonisolatedIsSpecial(const DeclContext *dc) {
+  ASTContext &ctx = dc->getASTContext();
+  if (ctx.LangOpts.hasFeature(Feature::NoExplicitNonIsolated))
+    return false;
+
+  return getDefaultIsolationForContext(dc) == DefaultIsolation::Nonisolated;
+}
+
 /// Infer isolation from witnessed protocol requirements.
 static std::optional<InferredActorIsolation>
 getIsolationFromWitnessedRequirements(ValueDecl *value) {
@@ -5054,6 +5362,15 @@ getIsolationFromWitnessedRequirements(ValueDecl *value) {
   if (dc->getSelfProtocolDecl())
     return std::nullopt;
 
+  if (explicitNonisolatedIsSpecial(dc)) {
+    // Prevent isolation inference from requirements if the conforming type
+    // has an explicit `nonisolated` attribute.
+    if (auto *NTD = dc->getSelfNominalTypeDecl()) {
+      if (NTD->getAttrs().hasAttribute<NonisolatedAttr>())
+        return std::nullopt;
+    }
+  }
+
   // Walk through each of the conformances in this context, collecting any
   // requirements that have actor isolation.
   auto conformances = idc->getLocalConformances( // note this
@@ -5062,6 +5379,11 @@ getIsolationFromWitnessedRequirements(ValueDecl *value) {
       std::tuple<ProtocolConformance *, ActorIsolation, ValueDecl *>;
   SmallVector<IsolatedRequirement, 2> isolatedRequirements;
   for (auto conformance : conformances) {
+    auto *implied =
+        conformance->getSourceKind() == ConformanceEntryKind::Implied
+            ? conformance->getImplyingConformance()
+            : nullptr;
+
     auto protocol = conformance->getProtocol();
     for (auto found : protocol->lookupDirect(value->getName())) {
       if (!isa<ProtocolDecl>(found->getDeclContext()))
@@ -5071,6 +5393,19 @@ getIsolationFromWitnessedRequirements(ValueDecl *value) {
       if (!requirement || isa<TypeDecl>(requirement))
         continue;
 
+      // The conformance implied by an explicitly stated nonisolated protocol
+      // makes all of the requirements nonisolated.
+      if (implied &&
+          implied->getSourceKind() == ConformanceEntryKind::Explicit) {
+        auto protocol = implied->getProtocol();
+        if (protocol->getAttrs().hasAttribute<NonisolatedAttr>()) {
+          isolatedRequirements.push_back(IsolatedRequirement{
+              implied, ActorIsolation::forNonisolated(/*unsafe=*/false),
+              requirement});
+          continue;
+        }
+      }
+
       auto requirementIsolation = getActorIsolation(requirement);
       switch (requirementIsolation) {
       case ActorIsolation::ActorInstance:
@@ -5080,10 +5415,24 @@ getIsolationFromWitnessedRequirements(ValueDecl *value) {
       case ActorIsolation::Erased:
         llvm_unreachable("requirement cannot have erased isolation");
 
+      case ActorIsolation::CallerIsolationInheriting: {
+        if (value->isAsync())
+          break;
+
+        // It's possible to witness requirement with an non-async
+        // declaration, in such cases `nonisolated(nonsending)` does
+        // not apply.
+        continue;
+      }
+
       case ActorIsolation::GlobalActor:
+        break;
+
       case ActorIsolation::Nonisolated:
-      case ActorIsolation::CallerIsolationInheriting:
       case ActorIsolation::NonisolatedUnsafe:
+        if (!explicitNonisolatedIsSpecial(requirement->getDeclContext()))
+          continue;
+
         break;
       }
 
@@ -5127,7 +5476,6 @@ getIsolationFromWitnessedRequirements(ValueDecl *value) {
         // Substitute into the global actor type.
         auto conformance = std::get<0>(isolated);
         auto requirementSubs = SubstitutionMap::getProtocolSubstitutions(
-            conformance->getProtocol(), dc->getSelfInterfaceType(),
             ProtocolConformanceRef(conformance));
         Type globalActor = isolation.getGlobalActor().subst(requirementSubs);
         if (!globalActorTypes.insert(globalActor->getCanonicalType()).second)
@@ -5182,23 +5530,39 @@ getIsolationFromConformances(NominalTypeDecl *nominal) {
     }
 
     auto *proto = conformance->getProtocol();
-    switch (auto protoIsolation = getActorIsolation(proto)) {
+    auto inferredIsolation = getInferredActorIsolation(proto);
+    auto protoIsolation = inferredIsolation.isolation;
+    switch (protoIsolation) {
     case ActorIsolation::ActorInstance:
     case ActorIsolation::Unspecified:
-    case ActorIsolation::Nonisolated:
     case ActorIsolation::CallerIsolationInheriting:
     case ActorIsolation::NonisolatedUnsafe:
       break;
+    case ActorIsolation::Nonisolated:
+      if (inferredIsolation.source.kind == IsolationSource::Kind::Explicit &&
+          explicitNonisolatedIsSpecial(nominal)) {
+        if (!foundIsolation) {
+          // We found an explicitly 'nonisolated' protocol.
+          foundIsolation = {
+              protoIsolation,
+              IsolationSource(proto, IsolationSource::Conformance)};
+        }
+        continue;
+      } else {
+        break;
+      }
 
     case ActorIsolation::Erased:
       llvm_unreachable("protocol cannot have erased isolation");
 
     case ActorIsolation::GlobalActor:
-      if (!foundIsolation) {
-        foundIsolation = {
-          protoIsolation,
-          IsolationSource(proto, IsolationSource::Conformance)
-        };
+      // If we encountered an explicit globally isolated conformance, allow it
+      // to override the _nonisolated_ isolation.
+      if (!foundIsolation ||
+          (foundIsolation->isolation.isNonisolated() &&
+           conformance->getSourceKind() == ConformanceEntryKind::Explicit)) {
+        foundIsolation = {protoIsolation,
+                          IsolationSource(proto, IsolationSource::Conformance)};
         continue;
       }
 
@@ -5361,6 +5725,7 @@ getMemberIsolationPropagation(const ValueDecl *value) {
   case DeclKind::EnumElement:
   case DeclKind::Macro:
   case DeclKind::MacroExpansion:
+  case DeclKind::Using:
     return std::nullopt;
 
   case DeclKind::PatternBinding:
@@ -5677,8 +6042,8 @@ static void checkDeclWithIsolatedParameter(ValueDecl *value) {
   // Suggest removing global-actor attributes written on it, as its ignored.
   if (auto attr = value->getGlobalActorAttr()) {
     if (!attr->first->isImplicit()) {
-      value->diagnose(diag::isolated_parameter_combined_global_actor_attr,
-                      value->getDescriptiveKind())
+      value
+          ->diagnose(diag::isolated_parameter_combined_global_actor_attr, value)
           .fixItRemove(attr->first->getRangeWithAt())
           .warnUntilSwiftVersion(6);
     }
@@ -5687,8 +6052,7 @@ static void checkDeclWithIsolatedParameter(ValueDecl *value) {
   // Suggest removing `nonisolated` as it is also ignored
   if (auto attr = value->getAttrs().getAttribute<NonisolatedAttr>()) {
     if (!attr->isImplicit()) {
-      value->diagnose(diag::isolated_parameter_combined_nonisolated,
-                      value->getDescriptiveKind())
+      value->diagnose(diag::isolated_parameter_combined_nonisolated, value)
           .fixItRemove(attr->getRangeWithAt())
           .warnUntilSwiftVersion(6);
     }
@@ -5700,13 +6064,16 @@ static void addAttributesForActorIsolation(ValueDecl *value,
   ASTContext &ctx = value->getASTContext();
   switch (isolation) {
   case ActorIsolation::CallerIsolationInheriting:
-    value->getAttrs().add(new (ctx) ExecutionAttr(ExecutionKind::Caller,
-                                                  /*implicit=*/true));
+    value->getAttrs().add(new (ctx) NonisolatedAttr(
+        /*atLoc=*/{}, /*range=*/{}, NonIsolatedModifier::NonSending,
+        /*implicit=*/true));
     break;
   case ActorIsolation::Nonisolated:
   case ActorIsolation::NonisolatedUnsafe: {
-    value->getAttrs().add(new (ctx) NonisolatedAttr(
-        isolation == ActorIsolation::NonisolatedUnsafe, /*implicit=*/true));
+    value->getAttrs().add(NonisolatedAttr::createImplicit(
+        ctx, isolation == ActorIsolation::NonisolatedUnsafe
+                 ? NonIsolatedModifier::Unsafe
+                 : NonIsolatedModifier::None));
     break;
   }
   case ActorIsolation::GlobalActor: {
@@ -5737,6 +6104,62 @@ static void addAttributesForActorIsolation(ValueDecl *value,
     }
 }
 
+/// Determine whether there is a SendableMetatype conformance that requires that the nominal type
+/// be nonisolated (preventing @MainActor inference).
+static bool sendableConformanceRequiresNonisolated(NominalTypeDecl *nominal) {
+  ASTContext &ctx = nominal->getASTContext();
+  if (isa<ProtocolDecl>(nominal))
+    return false;
+
+  auto sendable = ctx.getProtocol(KnownProtocolKind::Sendable);
+  auto sendableMetatype = ctx.getProtocol(KnownProtocolKind::SendableMetatype);
+  if (!sendableMetatype)
+    return false;
+
+  // Check whether any of the explicit conformances is to a
+  // SendableMetatype-inheriting protocol. We exclude direct conformance to
+  // Sendable here, because a global-actor-isolated type is implicitly Sendable,
+  // and writing Sendable explicitly
+  InvertibleProtocolSet inverses;
+  bool anyObject = false;
+  auto inherited = getDirectlyInheritedNominalTypeDecls(
+      nominal, inverses, anyObject);
+  for (const auto &entry : inherited) {
+    auto proto = dyn_cast<ProtocolDecl>(entry.Item);
+    if (proto && proto != sendable && proto->inheritsFrom(sendableMetatype))
+      return true;
+  }
+
+  // Check for member or extension macros that define conformances to
+  // SendableMetatype-inheriting protocols.
+  bool requiresNonisolated = false;
+  auto checkMacro = [&](MacroRole role, MacroDecl *macro) {
+    if (!macro || requiresNonisolated)
+      return;
+
+    SmallVector<ProtocolDecl *, 2> conformances;
+    macro->getIntroducedConformances(nominal, role, conformances);
+    for (auto proto : conformances) {
+      if (proto == sendableMetatype || proto->inheritsFrom(sendableMetatype)) {
+        requiresNonisolated = true;
+        break;
+      }
+    }
+  };
+
+  nominal->forEachAttachedMacro(
+      MacroRole::Member,
+      [&](CustomAttr * attr, MacroDecl *macro) {
+        checkMacro(MacroRole::Member, macro);
+      });
+  nominal->forEachAttachedMacro(
+      MacroRole::Extension,
+      [&](CustomAttr * attr, MacroDecl *macro) {
+        checkMacro(MacroRole::Extension, macro);
+      });
+  return requiresNonisolated;
+}
+
 /// Determine the default isolation and isolation source for this declaration,
 /// which may still be overridden by other inference rules.
 static std::tuple<InferredActorIsolation, ValueDecl *,
@@ -5750,62 +6173,98 @@ computeDefaultInferredActorIsolation(ValueDecl *value) {
     auto globalActorHelper = [&](Type globalActor)
         -> std::optional<std::tuple<InferredActorIsolation, ValueDecl *,
                                     std::optional<ActorIsolation>>> {
-      // Default global actor isolation does not apply to any declarations
-      // within actors and distributed actors.
-      bool inActorContext = false;
+      // Default main actor only applies to top-level declarations and
+      // in contexts that are also main actor isolated. It does not apply
+      // in {distributed} actor-isolated contexts nor in nonisolated
+      // contexts.
+
+      if (value->getDeclContext()->isLocalContext()) {
+        // Local storage is always nonisolated; region isolation computes
+        // whether the value is in an actor-isolated region based on
+        // the initializer expression.
+        auto *var = dyn_cast<VarDecl>(value);
+        if (var && var->hasStorage())
+          return {};
+
+        // Other local declarations must check the isolation of their
+        // decl context.
+        auto contextIsolation =
+            getActorIsolationOfContext(value->getDeclContext());
+        if (!contextIsolation.isMainActor())
+          return {};
+      }
+
+      // Members and nested types must check the isolation of the enclosing
+      // nominal type.
       auto *dc = value->getInnermostDeclContext();
-      while (dc && !inActorContext) {
+      while (dc) {
         if (auto *nominal = dc->getSelfNominalTypeDecl()) {
-          inActorContext = nominal->isAnyActor();
+          if (nominal->isAnyActor())
+            return {};
+
+          if (dc != dyn_cast<DeclContext>(value)) {
+            // If the nominal type is global-actor-isolated, there's nothing
+            // more to look for.
+            if (getActorIsolation(nominal).isMainActor())
+              break;
+
+            // If this is an extension of a nonisolated type, its isolation
+            // is independent of the type.
+            if (auto ext = dyn_cast<ExtensionDecl>(dc)) {
+              // If there were isolation attributes on the extension, respect
+              // them.
+              if (getIsolationFromAttributes(ext).has_value())
+                return {};
+
+              // Keep looking.
+            } else {
+              // The type is nonisolated, so its members are nonisolated.
+              return {};
+            }
+          }
         }
+
         dc = dc->getParent();
       }
 
-      if (!inActorContext) {
-        // FIXME: deinit should be implicitly MainActor too.
-        if (isa<TypeDecl>(value) || isa<ExtensionDecl>(value) ||
-            isa<AbstractStorageDecl>(value) || isa<FuncDecl>(value) ||
-            isa<ConstructorDecl>(value)) {
-          return {
-              {{ActorIsolation::forGlobalActor(globalActor), {}}, nullptr, {}}};
-        }
+      // If this is or is a non-type member of a nominal type that conforms to a
+      // SendableMetatype-inheriting protocol in its primary definition, disable
+      // @MainActor inference.
+      auto nominalTypeDecl = dyn_cast<NominalTypeDecl>(value);
+      if (!nominalTypeDecl && !isa<TypeDecl>(value)) {
+        nominalTypeDecl = value->getDeclContext()->getSelfNominalTypeDecl();
+      }
+      if (nominalTypeDecl &&
+          sendableConformanceRequiresNonisolated(nominalTypeDecl))
+        return { };
+
+      if (isa<TypeDecl>(value) || isa<ExtensionDecl>(value) ||
+          isa<AbstractStorageDecl>(value) ||
+          isa<AbstractFunctionDecl>(value)) {
+          // Preconcurrency here is used to stage the diagnostics
+          // when users select `@MainActor` default isolation with
+          // non-strict concurrency modes (pre Swift 6).
+          auto isolation =
+              ActorIsolation::forGlobalActor(globalActor)
+                  .withPreconcurrency(!ctx.LangOpts.isSwiftVersionAtLeast(6));
+          return {{{isolation, {}}, nullptr, {}}};
       }
 
       return {};
     };
 
-    // Otherwise, see if we have one specified by our file unit.
-    bool ignoreUnspecifiedMeansMainActorIsolated = false;
-    if (ctx.LangOpts.hasFeature(Feature::SwiftSettings)) {
-      if (auto *sourceFile = value->getDeclContext()->getParentSourceFile()) {
-        auto options = sourceFile->getLanguageOptions();
-        if (auto isolation = options.defaultIsolation) {
-          if (*isolation) {
-            auto result = globalActorHelper(*options.defaultIsolation);
-            if (result)
-              return *result;
-          } else {
-            // If we found a nil type, then we know we should ignore unspecified
-            // means main actor isolated.
-            ignoreUnspecifiedMeansMainActorIsolated = true;
-          }
-        }
-      }
-    }
-
+    DefaultIsolation defaultIsolation =
+        getDefaultIsolationForContext(value->getDeclContext());
     // If we are required to use main actor... just use that.
-    if (!ignoreUnspecifiedMeansMainActorIsolated &&
-        ctx.LangOpts.DefaultIsolationBehavior == DefaultIsolation::MainActor)
+    if (defaultIsolation == DefaultIsolation::MainActor)
       if (auto result =
               globalActorHelper(ctx.getMainActorType()->mapTypeOutOfContext()))
         return *result;
   }
 
-  // If we have an async function... by default we inherit isolation.
-  if (ctx.LangOpts.hasFeature(Feature::AsyncCallerExecution)) {
-    if (auto *func = dyn_cast<AbstractFunctionDecl>(value);
-        func && func->hasAsync() &&
-        func->getModuleContext() == ctx.MainModule) {
+  // If we have an async function or storage... by default we inherit isolation.
+  if (ctx.LangOpts.hasFeature(Feature::NonisolatedNonsendingByDefault)) {
+    if (value->isAsync() && value->getModuleContext() == ctx.MainModule) {
       return {
           {ActorIsolation::forCallerIsolationInheriting(), {}}, nullptr, {}};
     }
@@ -5833,6 +6292,22 @@ computeDefaultInferredActorIsolation(ValueDecl *value) {
     // Use the overridden decl's isolation as the default isolation for this
     // decl.
     auto isolation = getOverriddenIsolationFor(value);
+
+    // If this is an override of an async completion handler, mark
+    // it `@concurrent` instead of inferring `nonisolated(nonsending)`
+    // to preserve pre-SE-0461 behavior.
+    if (isolation.isCallerIsolationInheriting() &&
+        overriddenValue->hasClangNode()) {
+      if (auto *AFD = dyn_cast<AbstractFunctionDecl>(overriddenValue)) {
+        if (AFD->getForeignAsyncConvention()) {
+          return {{ActorIsolation::forNonisolated(/*unsafe=*/false),
+                   IsolationSource(overriddenValue, IsolationSource::Override)},
+                  overriddenValue,
+                  isolation};
+        }
+      }
+    }
+
     return {{isolation,
              IsolationSource(overriddenValue, IsolationSource::Override)},
             overriddenValue,
@@ -5840,12 +6315,57 @@ computeDefaultInferredActorIsolation(ValueDecl *value) {
                         // isolation for this decl.
   }
 
+  // Asynchronous variants for functions imported from ObjC are
+  // `nonisolated(nonsending)` by default.
+  if (value->hasClangNode() && value->isAsync() &&
+      !isa<ProtocolDecl>(value->getDeclContext())) {
+    return {{ActorIsolation::forCallerIsolationInheriting(), {}}, nullptr, {}};
+  }
+
   // We did not find anything special, return unspecified.
   return {{ActorIsolation::forUnspecified(), {}}, nullptr, {}};
 }
 
+/// Determines when the given "self" isolation should override default
+/// isolation.
+static bool shouldSelfIsolationOverrideDefault(
+    ASTContext &ctx, const DeclContext *dc,
+    const ActorIsolation &selfIsolation) {
+  switch (selfIsolation) {
+  case ActorIsolation::ActorInstance:
+  case ActorIsolation::Erased:
+  case ActorIsolation::GlobalActor:
+    // Actor isolation always overrides.
+    return true;
+
+  case ActorIsolation::Unspecified:
+    // Unspecified isolation never overrides.
+    return false;
+
+  case ActorIsolation::Nonisolated:
+  case ActorIsolation::NonisolatedUnsafe:
+  case ActorIsolation::CallerIsolationInheriting:
+    // Explicit nonisolated used to overwrite default isolation all the time,
+    // but under NoExplicitNonIsolated it doesn't affect extensions.
+    if (isa<NominalTypeDecl>(dc))
+      return true;
+
+    /// Only allow explicit nonisolated to override the default when it's
+    /// treated as special.
+    return explicitNonisolatedIsSpecial(dc);
+  }
+}
+
 static InferredActorIsolation computeActorIsolation(Evaluator &evaluator,
                                                     ValueDecl *value) {
+  // Defer bodies share the actor isolation of their enclosing context.
+  if (value->isDeferBody()) {
+    return {
+      getActorIsolationOfContext(value->getDeclContext()),
+      IsolationSource()
+    };
+  }
+
   // If this declaration has actor-isolated "self", it's isolated to that
   // actor.
   if (evaluateOrDefault(evaluator, HasIsolatedSelfRequest{value}, false)) {
@@ -5891,13 +6411,17 @@ static InferredActorIsolation computeActorIsolation(Evaluator &evaluator,
   // did not have an ExecutionKind::Caller attached to it.
   //
   // DISCUSSION: This occurs when we have a value decl that is explicitly marked
-  // as nonisolated but since AsyncCallerExecution is enabled, we return
+  // as nonisolated but since NonisolatedNonsendingByDefault is enabled, we return
   // CallerIsolationInheriting.
   if (isolationFromAttr && isolationFromAttr->getKind() ==
-          ActorIsolation::CallerIsolationInheriting &&
-      !value->getAttrs().hasAttribute<ExecutionAttr>()) {
-    value->getAttrs().add(new (ctx) ExecutionAttr(ExecutionKind::Caller,
-                                                  /*implicit=*/true));
+          ActorIsolation::CallerIsolationInheriting) {
+    auto nonisolated = value->getAttrs().getAttribute<NonisolatedAttr>();
+    // Replace `nonisolated` with `nonisolated(nonsending)`
+    if (!nonisolated || !nonisolated->isNonSending()) {
+      value->getAttrs().removeAttribute(nonisolated);
+      value->getAttrs().add(NonisolatedAttr::createImplicit(
+          ctx, NonIsolatedModifier::NonSending));
+    }
   }
 
   if (auto *fd = dyn_cast<FuncDecl>(value)) {
@@ -6008,11 +6532,18 @@ static InferredActorIsolation computeActorIsolation(Evaluator &evaluator,
     return inferred;
   };
 
+  // If this is an accessor, use the actor isolation of its storage
+  // declaration. All of the logic for FuncDecls below only applies to
+  // non-accessor functions.
+  if (auto accessor = dyn_cast<AccessorDecl>(value)) {
+    return getInferredActorIsolation(accessor->getStorage());
+  }
+
   // If this is a local function, inherit the actor isolation from its
   // context if it global or was captured.
   if (auto func = dyn_cast<FuncDecl>(value)) {
-    if (func->isLocalCapture() && !func->isSendable()) {
-      auto *dc = func->getDeclContext();
+    auto *dc = func->getDeclContext();
+    if (dc->isLocalContext() && !func->isSendable()) {
       llvm::PointerUnion<Decl *, AbstractClosureExpr *> inferenceSource;
       if (auto *closure = dyn_cast<AbstractClosureExpr>(dc)) {
         inferenceSource = closure;
@@ -6020,38 +6551,18 @@ static InferredActorIsolation computeActorIsolation(Evaluator &evaluator,
         inferenceSource = dc->getAsDecl();
       }
 
-      switch (auto enclosingIsolation = getActorIsolationOfContext(dc)) {
-      case ActorIsolation::Nonisolated:
-      case ActorIsolation::CallerIsolationInheriting:
-      case ActorIsolation::NonisolatedUnsafe:
-      case ActorIsolation::Unspecified:
-        // Do nothing.
-        break;
-
-      case ActorIsolation::Erased:
-        llvm_unreachable("context cannot have erased isolation");
-
-      case ActorIsolation::ActorInstance:
-        return {
-          inferredIsolation(enclosingIsolation),
-          IsolationSource(inferenceSource, IsolationSource::LexicalContext)
-        };
-
-      case ActorIsolation::GlobalActor:
-        return {
-          inferredIsolation(enclosingIsolation),
-          IsolationSource(inferenceSource, IsolationSource::LexicalContext)
-        };
-      }
+      auto enclosingIsolation = getActorIsolationOfContext(dc);
+      auto isolation =
+        computeClosureIsolationFromParent(func, enclosingIsolation,
+                                          /*checkIsolatedCapture*/true)
+          .withPreconcurrency(enclosingIsolation.preconcurrency());
+      return {
+        inferredIsolation(isolation),
+        IsolationSource(inferenceSource, IsolationSource::LexicalContext)
+      };
     }
   }
 
-  // If this is an accessor, use the actor isolation of its storage
-  // declaration.
-  if (auto accessor = dyn_cast<AccessorDecl>(value)) {
-    return getInferredActorIsolation(accessor->getStorage());
-  }
-
   if (auto var = dyn_cast<VarDecl>(value)) {
     auto &ctx = var->getASTContext();
     if (!ctx.LangOpts.isConcurrencyModelTaskToThread() &&
@@ -6185,14 +6696,12 @@ static InferredActorIsolation computeActorIsolation(Evaluator &evaluator,
     // has isolation, use that.
     if (auto selfTypeDecl = value->getDeclContext()->getSelfNominalTypeDecl()) {
       auto selfTypeIsolation = getInferredActorIsolation(selfTypeDecl);
-      if (selfTypeIsolation.isolation) {
+      if (shouldSelfIsolationOverrideDefault(
+              ctx, value->getDeclContext(), selfTypeIsolation.isolation)) {
         auto isolation = selfTypeIsolation.isolation;
 
-        if (auto *func = dyn_cast<AbstractFunctionDecl>(value);
-            ctx.LangOpts.hasFeature(
-                Feature::AsyncCallerExecution) &&
-            func && func->hasAsync() &&
-            func->getModuleContext() == ctx.MainModule &&
+        if (ctx.LangOpts.hasFeature(Feature::NonisolatedNonsendingByDefault) &&
+            value->isAsync() && value->getModuleContext() == ctx.MainModule &&
             isolation.isNonisolated()) {
           isolation = ActorIsolation::forCallerIsolationInheriting();
         }
@@ -6235,8 +6744,8 @@ InferredActorIsolation ActorIsolationRequest::evaluate(Evaluator &evaluator,
   const auto inferredIsolation = computeActorIsolation(evaluator, value);
 
   auto &ctx = value->getASTContext();
-  if (ctx.LangOpts.getFeatureState(Feature::AsyncCallerExecution)
-          .isEnabledForAdoption()) {
+  if (ctx.LangOpts.getFeatureState(Feature::NonisolatedNonsendingByDefault)
+          .isEnabledForMigration()) {
     warnAboutNewNonisolatedAsyncExecutionBehavior(ctx, value,
                                                   inferredIsolation.isolation);
   }
@@ -6296,7 +6805,8 @@ bool HasIsolatedSelfRequest::evaluate(
     }
   }
   if (attrIsolation) {
-    return attrIsolation == ActorIsolation::forActorInstanceSelf(selfTypeDecl);
+    return attrIsolation->getKind() == ActorIsolation::ActorInstance &&
+           attrIsolation->isActorInstanceForSelfParameter();
   }
 
   // If this is a variable, check for a property wrapper that alters its
@@ -6394,6 +6904,43 @@ DefaultInitializerIsolation::evaluate(Evaluator &evaluator,
   return requiredIsolation;
 }
 
+std::optional<DefaultIsolation>
+DefaultIsolationInSourceFileRequest::evaluate(Evaluator &evaluator,
+                                              const SourceFile *file) const {
+  llvm::SmallVector<Decl *> usingDecls;
+  llvm::copy_if(file->getTopLevelDecls(), std::back_inserter(usingDecls),
+                [](Decl *D) { return isa<UsingDecl>(D); });
+
+  if (usingDecls.empty())
+    return std::nullopt;
+
+  std::optional<std::pair<Decl *, DefaultIsolation>> isolation;
+
+  auto setIsolation = [&isolation](Decl *D, DefaultIsolation newIsolation) {
+    if (isolation) {
+      D->diagnose(diag::invalid_redecl_of_file_isolation);
+      isolation->first->diagnose(diag::invalid_redecl_of_file_isolation_prev);
+      return;
+    }
+
+    isolation = std::make_pair(D, newIsolation);
+  };
+
+  for (auto *D : usingDecls) {
+    switch (cast<UsingDecl>(D)->getSpecifier()) {
+    case UsingSpecifier::MainActor:
+      setIsolation(D, DefaultIsolation::MainActor);
+      break;
+    case UsingSpecifier::Nonisolated:
+      setIsolation(D, DefaultIsolation::Nonisolated);
+      break;
+    }
+  }
+
+  return isolation.has_value() ? std::optional(isolation->second)
+                               : std::nullopt;
+}
+
 void swift::checkOverrideActorIsolation(ValueDecl *value) {
   if (isa<TypeDecl>(value))
     return;
@@ -6656,11 +7203,16 @@ static bool checkSendableInstanceStorage(
         if (property->supportsMutation() && isolation.isUnspecified()) {
           auto behavior =
               SendableCheckContext(dc, check).defaultDiagnosticBehavior();
+          // If Sendable came from a `@preconcurrency` protocol the error
+          // should be downgraded even with strict concurrency checking to
+          // allow clients time to address the new requirement.
+          auto preconcurrency =
+              check == SendableCheck::ImpliedByPreconcurrencyProtocol;
           if (behavior != DiagnosticBehavior::Ignore) {
             property
                 ->diagnose(diag::concurrent_value_class_mutable_property,
                            property->getName(), nominal)
-                .limitBehaviorUntilSwiftVersion(behavior, 6);
+                .limitBehaviorWithPreconcurrency(behavior, preconcurrency);
           }
           invalid = invalid || (behavior == DiagnosticBehavior::Unspecified);
           return true;
@@ -6671,59 +7223,22 @@ static bool checkSendableInstanceStorage(
         }
       }
 
-      // Check that the property type is Sendable.
-      SendableCheckContext context(dc, check);
-      diagnoseNonSendableTypes(
-          propertyType, context,
-          /*inDerivedConformance*/Type(), property->getLoc(),
-          [&](Type type, DiagnosticBehavior behavior) {
-            auto preconcurrency =
-                context.preconcurrencyBehavior(type->getAnyNominal());
-            if (isImplicitSendableCheck(check)) {
-              // If this is for an externally-visible conformance, fail.
-              if (check == SendableCheck::ImplicitForExternallyVisible) {
-                invalid = true;
-                return true;
-              }
-
-              // If we are to ignore this diagnostic, just continue.
-              if (behavior == DiagnosticBehavior::Ignore ||
-                  preconcurrency == DiagnosticBehavior::Ignore)
-                return true;
-
-              invalid = true;
-              return true;
-            }
-
-            if (preconcurrency)
-              behavior = preconcurrency.value();
-
-            property
-                ->diagnose(diag::non_concurrent_type_member, propertyType,
-                           false, property->getName(), nominal)
-                .limitBehaviorWithPreconcurrency(behavior,
-                                                 preconcurrency.has_value());
-            return false;
-          });
-
-      if (invalid) {
-        // For implicit checks, bail out early if anything failed.
-        if (isImplicitSendableCheck(check))
-          return true;
-      }
-
-      return false;
+      return checkSendabilityOfMemberType(property, propertyType);
     }
 
     /// Handle an enum associated value.
     bool operator()(EnumElementDecl *element, Type elementType) override {
-      SendableCheckContext context (dc, check);
+      return checkSendabilityOfMemberType(element, elementType);
+    }
+
+  private:
+    bool checkSendabilityOfMemberType(ValueDecl *member, Type memberType) {
+      SendableCheckContext context(dc, check);
       diagnoseNonSendableTypes(
-          elementType, context,
-          /*inDerivedConformance*/Type(), element->getLoc(),
+          memberType, context,
+          /*inDerivedConformance*/ Type(), member->getLoc(),
           [&](Type type, DiagnosticBehavior behavior) {
-            auto preconcurrency =
-                context.preconcurrencyBehavior(type->getAnyNominal());
+            auto preconcurrencyBehavior = context.preconcurrencyBehavior(type);
             if (isImplicitSendableCheck(check)) {
               // If this is for an externally-visible conformance, fail.
               if (check == SendableCheck::ImplicitForExternallyVisible) {
@@ -6733,21 +7248,29 @@ static bool checkSendableInstanceStorage(
 
               // If we are to ignore this diagnostic, just continue.
               if (behavior == DiagnosticBehavior::Ignore ||
-                  preconcurrency == DiagnosticBehavior::Ignore)
+                  preconcurrencyBehavior == DiagnosticBehavior::Ignore)
                 return true;
 
               invalid = true;
               return true;
             }
 
-            if (preconcurrency)
-              behavior = preconcurrency.value();
-
-            element
-                ->diagnose(diag::non_concurrent_type_member, type, true,
-                           element->getName(), nominal)
-                .limitBehaviorWithPreconcurrency(behavior,
-                                                 preconcurrency.has_value());
+            // If Sendable came from a `@preconcurrency` protocol the error
+            // should be downgraded even with strict concurrency checking to
+            // allow clients time to address the new requirement.
+            bool fromPreconcurrencyConformance =
+                check == SendableCheck::ImpliedByPreconcurrencyProtocol;
+
+            if (preconcurrencyBehavior)
+              behavior = preconcurrencyBehavior.value();
+
+            member
+                ->diagnose(diag::non_concurrent_type_member, type,
+                           isa<EnumElementDecl>(member), member->getName(),
+                           nominal, type->isEqual(memberType))
+                .limitBehaviorWithPreconcurrency(
+                    behavior, fromPreconcurrencyConformance ||
+                                  preconcurrencyBehavior.has_value());
             return false;
           });
 
@@ -6759,6 +7282,7 @@ static bool checkSendableInstanceStorage(
 
       return false;
     }
+
   } visitor(nominal, dc, check);
 
   return visitor.visit(nominal, dc) || visitor.invalid;
@@ -6766,6 +7290,9 @@ static bool checkSendableInstanceStorage(
 
 bool swift::checkSendableConformance(
     ProtocolConformance *conformance, SendableCheck check) {
+  ASSERT(conformance->getProtocol()->isSpecificProtocol(
+           KnownProtocolKind::Sendable));
+
   auto conformanceDC = conformance->getDeclContext();
   auto nominal = conformance->getType()->getAnyNominal();
   if (!nominal)
@@ -6855,13 +7382,16 @@ bool swift::checkSendableConformance(
     return false;
   }
 
+  // An implied conformance is generated when you state a conformance to
+  // a protocol P that inherits from Sendable.
+  bool wasImplied = (conformance->getSourceKind() ==
+                     ConformanceEntryKind::Implied);
+
   // Sendable can only be used in the same source file.
   auto conformanceDecl = conformanceDC->getAsDecl();
   SendableCheckContext checkContext(conformanceDC, check);
   DiagnosticBehavior behavior = checkContext.defaultDiagnosticBehavior();
-  if (conformance->getSourceKind() == ConformanceEntryKind::Implied &&
-      conformance->getProtocol()->isSpecificProtocol(
-          KnownProtocolKind::Sendable)) {
+  if (wasImplied) {
     if (auto optBehavior = checkContext.preconcurrencyBehavior(
             nominal, /*ignoreExplicitConformance=*/true))
       behavior = *optBehavior;
@@ -6870,12 +7400,14 @@ bool swift::checkSendableConformance(
   if (conformanceDC->getOutermostParentSourceFile() &&
       conformanceDC->getOutermostParentSourceFile() !=
       nominal->getOutermostParentSourceFile()) {
-    conformanceDecl->diagnose(diag::concurrent_value_outside_source_file,
-                              nominal)
-      .limitBehaviorUntilSwiftVersion(behavior, 6);
+    if (!(nominal->hasClangNode() && wasImplied)) {
+      conformanceDecl->diagnose(diag::concurrent_value_outside_source_file,
+                                nominal)
+        .limitBehaviorUntilSwiftVersion(behavior, 6);
 
-    if (behavior == DiagnosticBehavior::Unspecified)
-      return true;
+      if (behavior == DiagnosticBehavior::Unspecified)
+        return true;
+    }
   }
 
   if (classDecl && classDecl->getParentSourceFile()) {
@@ -6883,9 +7415,9 @@ bool swift::checkSendableConformance(
 
     // An non-final class cannot conform to `Sendable`.
     if (!classDecl->isSemanticallyFinal()) {
-      classDecl->diagnose(diag::concurrent_value_nonfinal_class,
-                          classDecl->getName())
-        .limitBehaviorUntilSwiftVersion(behavior, 6);
+      classDecl->diagnose(diag::concurrent_value_nonfinal_class,classDecl->getName())
+          .fixItInsert(classDecl->getStartLoc(), "final")
+          .limitBehaviorUntilSwiftVersion(behavior, 6);
 
       if (behavior == DiagnosticBehavior::Unspecified)
         return true;
@@ -6913,7 +7445,7 @@ bool swift::checkSendableConformance(
   // a Sendable conformance. The implied conformance is unconditional, so check
   // the storage for sendability as if the conformance was declared on the nominal,
   // and not some (possibly constrained) extension.
-  if (conformance->getSourceKind() == ConformanceEntryKind::Implied)
+  if (wasImplied)
     conformanceDC = nominal;
   return checkSendableInstanceStorage(nominal, conformanceDC, check);
 }
@@ -7042,8 +7574,7 @@ ProtocolConformance *swift::deriveImplicitSendableConformance(
 
       ctx.evaluator.cacheOutput(ExtendedTypeRequest{extension},
                                 nominal->getDeclaredType());
-      ctx.evaluator.cacheOutput(ExtendedNominalRequest{extension},
-                                std::move(nominal));
+      extension->setExtendedNominal(nominal);
       nominal->addExtension(extension);
 
       // Make it accessible to getTopLevelDecls()
@@ -7070,7 +7601,8 @@ ProtocolConformance *swift::deriveImplicitSendableConformance(
       options |= ProtocolConformanceFlags::Unchecked;
     auto conformance = ctx.getNormalConformance(
         nominal->getDeclaredInterfaceType(), proto, nominal->getLoc(),
-        conformanceDC, ProtocolConformanceState::Complete, options);
+        /*inheritedTypeRepr=*/nullptr, conformanceDC,
+        ProtocolConformanceState::Complete, options);
     conformance->setSourceKindAndImplyingConformance(
         ConformanceEntryKind::Synthesized, nullptr);
 
@@ -7389,6 +7921,10 @@ AnyFunctionType *swift::adjustFunctionTypeForConcurrency(
       (isa<AbstractFunctionDecl>(decl) &&
        cast<AbstractFunctionDecl>(decl)->hasImplicitSelfDecl()));
   if (!hasImplicitSelfDecl) {
+    // Fast path.
+    if (fnType->getExtInfo().getIsolation() == *funcIsolation)
+      return fnType;
+
     return fnType->withExtInfo(
         fnType->getExtInfo().withIsolation(*funcIsolation));
   }
@@ -7398,6 +7934,10 @@ AnyFunctionType *swift::adjustFunctionTypeForConcurrency(
   if (!innerFnType)
     return fnType;
 
+  // Fast path.
+  if (innerFnType->getExtInfo().getIsolation() == *funcIsolation)
+    return fnType;
+
   // Update the inner function type with the isolation.
   innerFnType = innerFnType->withExtInfo(
       innerFnType->getExtInfo().withIsolation(*funcIsolation));
@@ -7538,7 +8078,7 @@ ActorIsolation swift::getActorIsolationForReference(ValueDecl *decl,
     // as needing to enter the actor.
     if (auto nominal = ctor->getDeclContext()->getSelfNominalTypeDecl()) {
       if (nominal->isAnyActor())
-        return ActorIsolation::forActorInstanceSelf(decl);
+        return ActorIsolation::forActorInstanceSelf(ctor);
     }
 
     // Fall through to treat initializers like any other declaration.
@@ -7625,6 +8165,7 @@ static bool isNonValueReference(const ValueDecl *value) {
   case DeclKind::PrefixOperator:
   case DeclKind::TopLevelCode:
   case DeclKind::MacroExpansion:
+  case DeclKind::Using:
     return true;
 
   case DeclKind::EnumElement:
@@ -7762,15 +8303,20 @@ ActorReferenceResult ActorReferenceResult::forReference(
         getInnermostIsolatedContext(fromDC, getClosureActorIsolation);
   }
 
+  if (declIsolation.isCallerIsolationInheriting())
+    return forSameConcurrencyDomain(declIsolation, options);
+
   // When the declaration is not actor-isolated, it can always be accessed
   // directly.
   if (!declIsolation.isActorIsolated()) {
+    if (declRef.getDecl()->getAttrs().hasAttribute<UnsafeInheritExecutorAttr>())
+      return forSameConcurrencyDomain(declIsolation, options);
+
     // If the declaration is asynchronous and we are in an actor-isolated
-    // context (of any kind), then we exit the actor to the nonisolated context.
-    if (decl->isAsync() && contextIsolation.isActorIsolated() &&
-        !declRef.getDecl()
-             ->getAttrs()
-             .hasAttribute<UnsafeInheritExecutorAttr>())
+    // context (of any kind) or it is a caller isolation inheriting, then
+    // we exit the actor to the nonisolated context.
+    if (decl->isAsync() && (contextIsolation.isActorIsolated() ||
+                            contextIsolation.isCallerIsolationInheriting()))
       return forExitsActorToNonisolated(contextIsolation, options);
 
     // Otherwise, we stay in the same concurrency domain, whether on an actor
@@ -7781,7 +8327,7 @@ ActorReferenceResult ActorReferenceResult::forReference(
   // The declaration we are accessing is actor-isolated. First, check whether
   // we are on the same actor already.
   if (actorInstance && declIsolation == ActorIsolation::ActorInstance &&
-      declIsolation.getActorInstanceParameter() == 0) {
+      declIsolation.isActorInstanceForSelfParameter()) {
     // If this instance is isolated, we're in the same concurrency domain.
     if (actorInstance->isIsolated())
       return forSameConcurrencyDomain(declIsolation, options);
@@ -7791,8 +8337,8 @@ ActorReferenceResult ActorReferenceResult::forReference(
     return forSameConcurrencyDomain(declIsolation, options);
   }
 
-  // Initializing an actor isolated stored property with a value effectively
-  // passes that value from the init context into the actor isolated context.
+  // Initializing an actor-isolated stored property with a value effectively
+  // passes that value from the init context into the actor-isolated context.
   // It's only okay for the value to cross isolation boundaries if the property
   // type is Sendable. Note that if the init is a nonisolated actor init,
   // Sendable checking is already performed on arguments at the call-site.
@@ -7806,7 +8352,7 @@ ActorReferenceResult ActorReferenceResult::forReference(
         // Treat the decl isolation as 'preconcurrency' to downgrade violations
         // to warnings, because violating Sendable here is accepted by the
         // Swift 5.9 compiler.
-        options |= Flags::Preconcurrency;
+        options |= Flags::CompatibilityDowngrade;
         return forEntersActor(declIsolation, options);
       }
     }
@@ -7845,8 +8391,10 @@ ActorReferenceResult ActorReferenceResult::forReference(
   // This is a cross-actor reference.
 
   // Note if the reference originates from a @preconcurrency-isolated context.
-  if (contextIsolation.preconcurrency() || declIsolation.preconcurrency())
+  if (contextIsolation.preconcurrency() || declIsolation.preconcurrency()) {
     options |= Flags::Preconcurrency;
+    options |= Flags::CompatibilityDowngrade;
+  }
 
   // If the declaration isn't asynchronous, promote to async.
   if (!decl->isAsync())
@@ -7875,43 +8423,65 @@ ActorReferenceResult ActorReferenceResult::forReference(
 
 bool swift::diagnoseNonSendableFromDeinit(
     SourceLoc refLoc, VarDecl *var, DeclContext *dc) {
-  return diagnoseIfAnyNonSendableTypes(var->getTypeInContext(),
-                                SendableCheckContext(dc),
-                                Type(),
-                                SourceLoc(),
-                                refLoc,
-                                diag::non_sendable_from_deinit,
-                                var->getDescriptiveKind(), var->getName());
+  return diagnoseIfAnyNonSendableTypes(
+      var->getTypeInContext(), SendableCheckContext(dc), Type(), SourceLoc(),
+      refLoc, diag::non_sendable_from_deinit, var);
 }
 
-ActorIsolation ProtocolConformance::getIsolation() const {
+std::optional<ActorIsolation> ProtocolConformance::getRawIsolation() const {
+  // Only normal protocol conformances can be isolated.
+  auto rootNormal =
+      dyn_cast<NormalProtocolConformance>(this->getRootConformance());
+  if (!rootNormal)
+    return ActorIsolation::forNonisolated(false);
+
+  if (this != rootNormal)
+    return rootNormal->getRawIsolation();
+
   ASTContext &ctx = getDeclContext()->getASTContext();
-  auto conformance = const_cast<ProtocolConformance *>(this);
+  auto conformance = const_cast<NormalProtocolConformance *>(rootNormal);
   return evaluateOrDefault(
-      ctx.evaluator, ConformanceIsolationRequest{conformance},
+      ctx.evaluator, RawConformanceIsolationRequest{conformance},
       ActorIsolation());
 }
 
-ActorIsolation
-ConformanceIsolationRequest::evaluate(Evaluator &evaluator, ProtocolConformance *conformance) const {
+ActorIsolation ProtocolConformance::getIsolation() const {
   // Only normal protocol conformances can be isolated.
   auto rootNormal =
-      dyn_cast<NormalProtocolConformance>(conformance->getRootConformance());
+      dyn_cast<NormalProtocolConformance>(this->getRootConformance());
   if (!rootNormal)
     return ActorIsolation::forNonisolated(false);
 
+  if (this != rootNormal)
+    return rootNormal->getIsolation();
+
+  ASTContext &ctx = getDeclContext()->getASTContext();
+  auto conformance = const_cast<NormalProtocolConformance *>(rootNormal);
+  return evaluateOrDefault(
+      ctx.evaluator, ConformanceIsolationRequest{conformance},
+      ActorIsolation());
+}
+
+std::optional<ActorIsolation>
+RawConformanceIsolationRequest::evaluate(
+    Evaluator &evaluator, NormalProtocolConformance *conformance
+) const {
   // If the conformance is explicitly non-isolated, report that.
-  if (rootNormal->getOptions().contains(ProtocolConformanceFlags::Nonisolated))
+  if (conformance->getOptions().contains(ProtocolConformanceFlags::Nonisolated))
     return ActorIsolation::forNonisolated(false);
 
+  auto dc = conformance->getDeclContext();
+  ASTContext &ctx = dc->getASTContext();
+  auto proto = conformance->getProtocol();
+
   // If there is an explicitly-specified global actor on the isolation,
   // resolve it and report it.
-  if (auto globalActorTypeExpr = rootNormal->getExplicitGlobalActorIsolation()) {
+  if (auto globalActorTypeExpr = conformance->getExplicitGlobalActorIsolation()) {
     // If we don't already have a resolved global actor type, resolve it now.
     Type globalActorType = globalActorTypeExpr->getInstanceType();
     if (!globalActorType) {
       const auto resolution = TypeResolution::forInterface(
-          rootNormal->getDeclContext(), std::nullopt,
+          conformance->getDeclContext(), std::nullopt,
           /*unboundTyOpener*/ nullptr,
           /*placeholderHandler*/ nullptr,
           /*packElementOpener*/ nullptr);
@@ -7923,33 +8493,141 @@ ConformanceIsolationRequest::evaluate(Evaluator &evaluator, ProtocolConformance
       globalActorTypeExpr->setType(MetatypeType::get(globalActorType));
     }
 
+    // Cannot form an isolated conformance to a SendableMetatype-inheriting
+    // protocol. Diagnose it.
+    if (auto sendableMetatype =
+            ctx.getProtocol(KnownProtocolKind::SendableMetatype)) {
+      if (proto->inheritsFrom(sendableMetatype)) {
+        bool isPreconcurrency = moduleImportForPreconcurrency(
+            proto, conformance->getDeclContext()) != nullptr;
+        isPreconcurrency |= proto->preconcurrency();
+        ctx.Diags.diagnose(
+            conformance->getLoc(),
+            diag::isolated_conformance_to_sendable_metatype,
+            ActorIsolation::forGlobalActor(globalActorType),
+            conformance->getType(),
+            proto)
+          .limitBehaviorIf(isPreconcurrency, DiagnosticBehavior::Warning);
+      }
+    }
+
     // FIXME: Make sure the type actually is a global actor type, map it into
     // context, etc.
 
     return ActorIsolation::forGlobalActor(globalActorType);
   }
 
-  auto dc = rootNormal->getDeclContext();
+  // If the protocol itself is isolated, don't infer isolation for the
+  // conformance.
+  if (getActorIsolation(proto).isActorIsolated())
+    return ActorIsolation::forNonisolated(false);
+
+  // SendableMetatype disables isolation inference.
+  auto sendableMetatypeProto =
+      ctx.getProtocol(KnownProtocolKind::SendableMetatype);
+  if (sendableMetatypeProto && proto->inheritsFrom(sendableMetatypeProto))
+    return ActorIsolation::forNonisolated(false);
+
+  // @preconcurrency disables isolation inference.
+  if (conformance->isPreconcurrency())
+    return ActorIsolation::forNonisolated(false);
+
+  return std::nullopt;
+}
+
+ActorIsolation swift::inferConformanceIsolation(
+    NormalProtocolConformance *conformance, bool hasKnownIsolatedWitness) {
+  auto dc = conformance->getDeclContext();
   ASTContext &ctx = dc->getASTContext();
-  if (!ctx.LangOpts.hasFeature(Feature::IsolatedConformances))
+
+  // If we aren't inferring isolated conformances, we're done.
+  if (!ctx.LangOpts.hasFeature(Feature::InferIsolatedConformances))
     return ActorIsolation::forNonisolated(false);
 
-  // If the protocol itself is isolated, don't infer isolation for the
-  // conformance.
-  if (getActorIsolation(rootNormal->getProtocol()).isActorIsolated())
+  auto nominal = dc->getSelfNominalTypeDecl();
+  if (!nominal) {
     return ActorIsolation::forNonisolated(false);
+  }
 
   // If we are inferring isolated conformances and the conforming type is
-  // isolated to a global actor,
-  auto nominal = dc->getSelfNominalTypeDecl();
-  if (ctx.LangOpts.hasFeature(Feature::InferIsolatedConformances) &&
-      nominal) {
-    auto nominalIsolation = getActorIsolation(nominal);
-    if (nominalIsolation.isGlobalActor())
-      return nominalIsolation;
+  // isolated to a global actor, we may use the conforming type's isolation.
+  auto nominalIsolation = getActorIsolation(nominal);
+  if (!nominalIsolation.isGlobalActor()) {
+    // If we are in an extension of the type, we might still infer an
+    // isolated conformance depending on default isolation and on the extension
+    // itself.
+    if (auto ext = dyn_cast<ExtensionDecl>(dc)) {
+      // If there's an isolation-related attribute on the extension, use it.
+      if (auto attrIsolation = getIsolationFromAttributes(ext))
+        return *attrIsolation;
+
+      // If we're defaulting to main-actor isolation, use that.
+      if (getDefaultIsolationForContext(dc) == DefaultIsolation::MainActor)
+        return ActorIsolation::forMainActor(ctx);
+    }
+
+    return ActorIsolation::forNonisolated(false);
+  }
+
+  // If all of the value witnesses are nonisolated, then we should not infer
+  // global actor isolation.
+  if (hasKnownIsolatedWitness) {
+    // The caller told us we have an isolated value witness, so infer
+    // the nominal isolation.
+    return nominalIsolation;
+  }
+
+  auto protocol = conformance->getProtocol();
+
+  // Also check the value witnesses of each implied conformance to every
+  // inherited protocol, recursively.
+  for (auto req : protocol->getRequirementSignature().getRequirements()) {
+    if (req.getKind() != RequirementKind::Conformance ||
+        !req.getFirstType()->isEqual(ctx.TheSelfType))
+      continue;
+
+    auto *assocConf = conformance->getAssociatedConformance(
+        req.getFirstType(), req.getProtocolDecl()).getConcrete();
+    auto isolation = assocConf->getIsolation();
+    if (isolation.isGlobalActor())
+      return isolation;
+  }
+
+  bool anyIsolatedWitness = false;
+  for (auto requirement : protocol->getProtocolRequirements()) {
+    if (isa<TypeDecl>(requirement))
+      continue;
+
+    auto valueReq = cast<ValueDecl>(requirement);
+    auto witness = conformance->getWitnessDecl(valueReq);
+    if (!witness)
+      continue;
+
+    auto witnessIsolation = getActorIsolation(witness);
+    if (witnessIsolation.isActorIsolated()) {
+      anyIsolatedWitness = true;
+      break;
+    }
+  }
+
+  if (!anyIsolatedWitness) {
+    return ActorIsolation::forNonisolated(false);
   }
 
-  return ActorIsolation::forNonisolated(false);
+  return nominalIsolation;
+}
+
+ActorIsolation
+ConformanceIsolationRequest::evaluate(
+    Evaluator &evaluator, NormalProtocolConformance *conformance
+) const {
+  // If there is raw isolation, use that.
+  if (auto rawIsolation = conformance->getRawIsolation())
+    return *rawIsolation;
+
+  // Otherwise, we may infer isolation.
+  return inferConformanceIsolation(
+      conformance, /*hasKnownIsolatedWitness=*/false);
 }
 
 namespace {
@@ -7958,11 +8636,14 @@ namespace {
   class MismatchedIsolatedConformances {
     llvm::TinyPtrVector<ProtocolConformance *> badIsolatedConformances;
     DeclContext *fromDC;
+    HandleConformanceIsolationFn handleBad;
     mutable std::optional<ActorIsolation> fromIsolation;
 
   public:
-    MismatchedIsolatedConformances(const DeclContext *fromDC)
-      : fromDC(const_cast<DeclContext *>(fromDC)) { }
+    MismatchedIsolatedConformances(const DeclContext *fromDC,
+                                   HandleConformanceIsolationFn handleBad)
+      : fromDC(const_cast<DeclContext *>(fromDC)),
+        handleBad(handleBad) { }
 
     ActorIsolation getContextIsolation() const {
       if (!fromIsolation)
@@ -8002,6 +8683,16 @@ namespace {
       if (badIsolatedConformances.empty())
         return false;
 
+      if (handleBad) {
+        // Capture all of the actor isolations from the conformances.
+        std::vector<ActorIsolation> badIsolations;
+        for (auto conformance : badIsolatedConformances)
+          badIsolations.push_back(conformance->getIsolation());
+
+        if (handleBad(badIsolations))
+          return false;
+      }
+
       ASTContext &ctx = fromDC->getASTContext();
       auto firstConformance = badIsolatedConformances.front();
       ctx.Diags.diagnose(
@@ -8009,39 +8700,48 @@ namespace {
           firstConformance->getIsolation(),
           firstConformance->getType(),
           firstConformance->getProtocol()->getName(),
-          getContextIsolation());
+          getContextIsolation())
+        .warnUntilSwiftVersion(6);
       return true;
     }
   };
 
 }
 
+bool swift::doNotDiagnoseConformanceIsolation(ArrayRef<ActorIsolation>) {
+  return false;
+}
+
 bool swift::checkIsolatedConformancesInContext(
-    ConcreteDeclRef declRef, SourceLoc loc, const DeclContext *dc) {
-  MismatchedIsolatedConformances mismatched(dc);
+    ConcreteDeclRef declRef, SourceLoc loc, const DeclContext *dc,
+    HandleConformanceIsolationFn handleBad) {
+  MismatchedIsolatedConformances mismatched(dc, handleBad);
   forEachConformance(declRef, mismatched);
   return mismatched.diagnose(loc);
 }
 
 bool swift::checkIsolatedConformancesInContext(
     ArrayRef<ProtocolConformanceRef> conformances, SourceLoc loc,
-    const DeclContext *dc) {
-  MismatchedIsolatedConformances mismatched(dc);
+    const DeclContext *dc,
+    HandleConformanceIsolationFn handleBad) {
+  MismatchedIsolatedConformances mismatched(dc, handleBad);
   for (auto conformance: conformances)
     forEachConformance(conformance, mismatched);
   return mismatched.diagnose(loc);
 }
 
 bool swift::checkIsolatedConformancesInContext(
-    SubstitutionMap subs, SourceLoc loc, const DeclContext *dc) {
-  MismatchedIsolatedConformances mismatched(dc);
+    SubstitutionMap subs, SourceLoc loc, const DeclContext *dc,
+    HandleConformanceIsolationFn handleBad) {
+  MismatchedIsolatedConformances mismatched(dc, handleBad);
   forEachConformance(subs, mismatched);
   return mismatched.diagnose(loc);
 }
 
 bool swift::checkIsolatedConformancesInContext(
-    Type type, SourceLoc loc, const DeclContext *dc) {
-  MismatchedIsolatedConformances mismatched(dc);
+    Type type, SourceLoc loc, const DeclContext *dc,
+    HandleConformanceIsolationFn handleBad) {
+  MismatchedIsolatedConformances mismatched(dc, handleBad);
   forEachConformance(type, mismatched);
   return mismatched.diagnose(loc);
 }
diff --git a/lib/Sema/TypeCheckConcurrency.h b/lib/Sema/TypeCheckConcurrency.h
index 6e74ecbf1ff52..50b01165ba306 100644
--- a/lib/Sema/TypeCheckConcurrency.h
+++ b/lib/Sema/TypeCheckConcurrency.h
@@ -23,6 +23,7 @@
 #include "swift/AST/Expr.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/Type.h"
+#include "swift/AST/TypeRepr.h"
 #include "swift/Sema/Concurrency.h"
 
 #include <cassert>
@@ -207,12 +208,20 @@ struct ActorReferenceResult {
     /// potentially from a different node, so it must be marked 'distributed'.
     Distributed = 1 << 2,
 
-    /// The declaration is being accessed from a @preconcurrency context.
+    /// The declaration is marked as `@preconcurrency` or being accessed
+    /// from a @preconcurrency context.
     Preconcurrency = 1 << 3,
 
     /// Only arguments cross an isolation boundary, e.g. because they
     /// escape into an actor in a nonisolated actor initializer.
     OnlyArgsCrossIsolation = 1 << 4,
+
+    /// The reference to the declaration is invalid but has to be downgraded
+    /// to a warning because it was accepted by the older compilers or because
+    /// the declaration predates concurrency and is marked as such.
+    ///
+    /// NOTE: This flag is set for `Preconcurrency` declarations.
+    CompatibilityDowngrade = 1 << 5,
   };
 
   using Options = OptionSet<Flags>;
@@ -326,6 +335,11 @@ bool diagnoseNonSendableTypesInReference(
 void diagnoseMissingSendableConformance(
     SourceLoc loc, Type type, const DeclContext *fromDC, bool preconcurrency);
 
+/// Produce a diagnostic for a missing conformance to SendableMetatype
+void diagnoseMissingSendableMetatypeConformance(SourceLoc loc, Type type,
+                                                const DeclContext *fromDC,
+                                                bool preconcurrency);
+
 /// If the given nominal type is public and does not explicitly
 /// state whether it conforms to Sendable, provide a diagnostic.
 void diagnoseMissingExplicitSendable(NominalTypeDecl *nominal);
@@ -352,7 +366,7 @@ enum class SendableCheck {
 
   /// Sendable conformance was implied by a protocol that inherits from
   /// Sendable and also predates concurrency.
-  ImpliedByStandardProtocol,
+  ImpliedByPreconcurrencyProtocol,
 
   /// Implicit conformance to Sendable.
   Implicit,
@@ -366,7 +380,7 @@ enum class SendableCheck {
 static inline bool isImplicitSendableCheck(SendableCheck check) {
   switch (check) {
   case SendableCheck::Explicit:
-  case SendableCheck::ImpliedByStandardProtocol:
+  case SendableCheck::ImpliedByPreconcurrencyProtocol:
     return false;
 
   case SendableCheck::Implicit:
@@ -407,10 +421,18 @@ struct SendableCheckContext {
   /// type in this context.
   DiagnosticBehavior diagnosticBehavior(NominalTypeDecl *nominal) const;
 
+  /// Determine the preconcurrency behavior when referencing the given
+  /// declaration from a type. This only has an effect when the declaration
+  /// is a nominal type.
   std::optional<DiagnosticBehavior> preconcurrencyBehavior(
       Decl *decl,
       bool ignoreExplicitConformance = false) const;
 
+  /// Determine the preconcurrency behavior when referencing the given
+  /// non-Sendable type. This only has an effect when the declaration
+  /// is a nominal or metatype type.
+  std::optional<DiagnosticBehavior> preconcurrencyBehavior(Type type) const;
+
   /// Whether to warn about a Sendable violation even in minimal checking.
   bool warnInMinimalChecking() const;
 };
@@ -436,6 +458,37 @@ namespace detail {
   };
 }
 
+/// Diagnose any non-Sendable types that occur within the given type, using
+/// the given diagnostic.
+///
+/// \returns \c true if any errors were produced, \c false if no diagnostics or
+/// only warnings and notes were produced or if a decl contains a sending
+/// parameter or result
+template <typename... DiagArgs>
+bool diagnoseNonSendableTypesWithSendingCheck(
+    ValueDecl *decl, Type type, SendableCheckContext fromContext,
+    Type derivedConformance, SourceLoc typeLoc, SourceLoc diagnoseLoc,
+    Diag<Type, DiagArgs...> diag,
+    typename detail::Identity<DiagArgs>::type... diagArgs) {
+  if (auto param = dyn_cast<ParamDecl>(decl)) {
+    if (param->isSending()) {
+      return false;
+    }
+  }
+  if (auto *func = dyn_cast<FuncDecl>(decl)) {
+    if (func->hasSendingResult())
+      return false;
+  }
+  if (auto *subscript = dyn_cast<SubscriptDecl>(decl)) {
+    if (isa_and_nonnull<SendingTypeRepr>(subscript->getResultTypeRepr()))
+      return false;
+  }
+
+  return diagnoseNonSendableTypes(
+      type, fromContext, derivedConformance, typeLoc, diagnoseLoc, diag,
+      std::forward<decltype(diagArgs)>(diagArgs)...);
+}
+
 /// Diagnose any non-Sendable types that occur within the given type, using
 /// the given diagnostic.
 ///
@@ -460,8 +513,7 @@ bool diagnoseNonSendableTypes(
       [&](Type specificType, DiagnosticBehavior behavior) {
         // FIXME: Reconcile preconcurrency declaration vs preconcurrency
         // import behavior.
-        auto preconcurrency =
-          fromContext.preconcurrencyBehavior(specificType->getAnyNominal());
+        auto preconcurrency = fromContext.preconcurrencyBehavior(specificType);
 
         ctx.Diags.diagnose(diagnoseLoc, diag, type, diagArgs...)
             .limitBehaviorWithPreconcurrency(behavior,
@@ -497,8 +549,7 @@ bool diagnoseIfAnyNonSendableTypes(
   diagnoseNonSendableTypes(
       type, fromContext, derivedConformance, typeLoc,
       [&](Type specificType, DiagnosticBehavior behavior) {
-        auto preconcurrency =
-          fromContext.preconcurrencyBehavior(specificType->getAnyNominal());
+        auto preconcurrency = fromContext.preconcurrencyBehavior(specificType);
 
         if (behavior == DiagnosticBehavior::Ignore ||
             preconcurrency == DiagnosticBehavior::Ignore)
@@ -696,12 +747,22 @@ void introduceUnsafeInheritExecutorReplacements(
 void introduceUnsafeInheritExecutorReplacements(
     const DeclContext *dc, Type base, SourceLoc loc, LookupResult &result);
 
+/// Function that attempts to handle all of the "bad" conformance isolation
+/// found somewhere, and returns true if it handled them. If not, returns
+/// false so that the conformances can be diagnose.
+using HandleConformanceIsolationFn =
+  llvm::function_ref<bool(ArrayRef<ActorIsolation>)>;
+
+/// Function used as a default HandleConformanceIsolationFn.
+bool doNotDiagnoseConformanceIsolation(ArrayRef<ActorIsolation>);
+
 /// Check for correct use of isolated conformances in the given reference.
 ///
 /// This checks that any isolated conformances that occur in the given
 /// declaration reference match the isolated of the context.
 bool checkIsolatedConformancesInContext(
-    ConcreteDeclRef declRef, SourceLoc loc, const DeclContext *dc);
+    ConcreteDeclRef declRef, SourceLoc loc, const DeclContext *dc,
+    HandleConformanceIsolationFn handleBad = doNotDiagnoseConformanceIsolation);
 
 /// Check for correct use of isolated conformances in the set given set of
 /// protocol conformances.
@@ -710,7 +771,8 @@ bool checkIsolatedConformancesInContext(
 /// declaration reference match the isolated of the context.
 bool checkIsolatedConformancesInContext(
     ArrayRef<ProtocolConformanceRef> conformances, SourceLoc loc,
-    const DeclContext *dc);
+    const DeclContext *dc,
+    HandleConformanceIsolationFn handleBad = doNotDiagnoseConformanceIsolation);
 
 /// Check for correct use of isolated conformances in the given substitution
 /// map.
@@ -718,14 +780,23 @@ bool checkIsolatedConformancesInContext(
 /// This checks that any isolated conformances that occur in the given
 /// substitution map match the isolated of the context.
 bool checkIsolatedConformancesInContext(
-    SubstitutionMap subs, SourceLoc loc, const DeclContext *dc);
+    SubstitutionMap subs, SourceLoc loc, const DeclContext *dc,
+    HandleConformanceIsolationFn handleBad = doNotDiagnoseConformanceIsolation);
 
 /// Check for correct use of isolated conformances in the given type.
 ///
 /// This checks that any isolated conformances that occur in the given
 /// type match the isolated of the context.
 bool checkIsolatedConformancesInContext(
-    Type type, SourceLoc loc, const DeclContext *dc);
+    Type type, SourceLoc loc, const DeclContext *dc,
+    HandleConformanceIsolationFn handleBad = doNotDiagnoseConformanceIsolation);
+
+/// For a protocol conformance that does not have a "raw" isolation, infer its isolation.
+///
+/// - hasKnownIsolatedWitness: indicates when it is known that there is an actor-isolated witness, meaning
+///   that this operation will not look at other witnesses to determine if they are all nonisolated.
+ActorIsolation inferConformanceIsolation(
+    NormalProtocolConformance *conformance, bool hasKnownIsolatedWitness);
 
 } // end namespace swift
 
diff --git a/lib/Sema/TypeCheckConstraints.cpp b/lib/Sema/TypeCheckConstraints.cpp
index 7a115626435b2..9d3c4fe2310e2 100644
--- a/lib/Sema/TypeCheckConstraints.cpp
+++ b/lib/Sema/TypeCheckConstraints.cpp
@@ -57,10 +57,8 @@ using namespace constraints;
 #pragma mark Type variable implementation
 
 void TypeVariableType::Implementation::print(llvm::raw_ostream &OS) {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
-  getTypeVariable()->print(OS, PO);
-  
+  getTypeVariable()->print(OS, PrintOptions::forDebugging());
+
   SmallVector<TypeVariableOptions, 4> bindingOptions;
   if (canBindToLValue())
     bindingOptions.push_back(TypeVariableOptions::TVO_CanBindToLValue);
@@ -204,6 +202,18 @@ bool TypeVariableType::Implementation::isCollectionLiteralType() const {
                      locator->directlyAt<DictionaryExpr>());
 }
 
+bool TypeVariableType::Implementation::isNumberLiteralType() const {
+  return locator && locator->directlyAt<NumberLiteralExpr>();
+}
+
+bool TypeVariableType::Implementation::isFunctionResult() const {
+  return locator && locator->isLastElement<LocatorPathElt::FunctionResult>();
+}
+
+bool TypeVariableType::Implementation::isTernary() const {
+  return locator && locator->directlyAt<TernaryExpr>();
+}
+
 void *operator new(size_t bytes, ConstraintSystem& cs,
                    size_t alignment) {
   return cs.getAllocator().Allocate(bytes, alignment);
@@ -296,7 +306,7 @@ Expr *ConstraintLocatorBuilder::trySimplifyToExpr() const {
   // Locators are not guaranteed to have an anchor
   // if constraint system is used to verify generic
   // requirements.
-  if (!anchor.is<Expr *>())
+  if (!isa<Expr *>(anchor))
     return nullptr;
 
   ArrayRef<LocatorPathElt> path = pathBuffer;
@@ -339,7 +349,16 @@ class SyntacticDiagnosticWalker final : public BaseDiagnosticWalker {
     // closures.
     if (ExprDepth == 0) {
       auto isExprStmt = (E == Target.getAsExpr()) ? IsTopLevelExprStmt : false;
-      performSyntacticExprDiagnostics(E, Target.getDeclContext(), isExprStmt);
+
+      bool isConstInitExpr = false;
+      if (Target.isForInitialization()) {
+        if (auto initPattern = Target.getInitializationPattern())
+          if (auto namedPatternVarDecl = initPattern->getSingleVar())
+            isConstInitExpr = namedPatternVarDecl->isConstValue();
+      }
+
+      performSyntacticExprDiagnostics(E, Target.getDeclContext(), isExprStmt,
+                                      isConstInitExpr);
     }
     ExprDepth += 1;
     return Action::Continue(E);
@@ -430,11 +449,11 @@ TypeChecker::typeCheckTarget(SyntacticElementTarget &target,
   // special handling. Returns true if handled, in which case we've already
   // type-checked it for completion, and don't need the solution applied.
   if (Context.CompletionCallback &&
-      typeCheckForCodeCompletion(target, /*needsPrecheck*/ false,
-                                 [&](const constraints::Solution &S) {
-                                   Context.CompletionCallback->sawSolution(S);
-                                 }))
+      typeCheckForCodeCompletion(target, [&](const constraints::Solution &S) {
+        Context.CompletionCallback->sawSolution(S);
+      })) {
     return std::nullopt;
+  }
 
   // Construct a constraint system from this expression.
   ConstraintSystemOptions csOptions = ConstraintSystemFlags::AllowFixes;
@@ -445,6 +464,13 @@ TypeChecker::typeCheckTarget(SyntacticElementTarget &target,
   if (options.contains(TypeCheckExprFlags::DisableMacroExpansions))
     csOptions |= ConstraintSystemFlags::DisableMacroExpansions;
 
+  if (Context.TypeCheckerOpts.EnableConstraintSolverPerformanceHacks ||
+      evaluateOrDefault(Context.evaluator,
+                        ModuleHasTypeCheckerPerformanceHacksEnabledRequest{
+                            dc->getParentModule()},
+                        false))
+    csOptions |= ConstraintSystemFlags::EnablePerformanceHacks;
+
   ConstraintSystem cs(dc, csOptions, diagnosticTransaction);
 
   if (auto *expr = target.getAsExpr()) {
@@ -599,7 +625,7 @@ Type TypeChecker::typeCheckParameterDefault(Expr *&defaultValue,
       if (auto *typeVar = findParam(GP))
         return typeVar;
 
-      auto *typeVar = cs.openGenericParameter(GP, locator);
+      auto *typeVar = cs.openGenericParameter(GP, locator, nullptr);
       genericParameters.emplace_back(GP, typeVar);
 
       return typeVar;
@@ -630,17 +656,26 @@ Type TypeChecker::typeCheckParameterDefault(Expr *&defaultValue,
   // Check whether generic parameters are only mentioned once in
   // the anchor's signature.
   {
-    auto anchorTy = anchor->getInterfaceType()->castTo<GenericFunctionType>();
+    auto anchorTy = anchor->getInterfaceType()->castTo<AnyFunctionType>();
+
+    if (anchor->hasCurriedSelf())
+      anchorTy = anchorTy->getResult()->castTo<AnyFunctionType>();
 
-    // Reject if generic parameters are used in multiple different positions
-    // in the parameter list.
+    SmallPtrSet<CanType, 4> inferrableParams;
+    collectReferencedGenericParams(paramInterfaceTy, inferrableParams);
 
     llvm::SmallVector<unsigned, 2> affectedParams;
     for (unsigned i : indices(anchorTy->getParams())) {
-      const auto &param = anchorTy->getParams()[i];
 
-      if (containsTypes(param.getPlainType()))
-        affectedParams.push_back(i);
+      SmallPtrSet<CanType, 4> referencedGenericParams;
+      collectReferencedGenericParams(anchorTy->getParams()[i].getPlainType(), referencedGenericParams);
+
+      for (auto can : referencedGenericParams) {
+        if (can->is<GenericTypeParamType>() && inferrableParams.contains(can)) {
+          affectedParams.push_back(i);
+          break;
+        }
+      }
     }
 
     if (affectedParams.size() > 1) {
@@ -651,12 +686,19 @@ Type TypeChecker::typeCheckParameterDefault(Expr *&defaultValue,
           affectedParams, [&](const unsigned index) { params << "#" << index; },
           [&] { params << ", "; });
 
-      ctx.Diags.diagnose(
+      auto diag = ctx.Diags.diagnose(
           defaultValue->getLoc(),
           diag::
               cannot_default_generic_parameter_inferrable_from_another_parameter,
           paramInterfaceTy, params.str());
-      return Type();
+
+      // In Swift 6.2 and below we incorrectly missed checking this rule for
+      // methods, downgrade to a warning until the next language mode.
+      auto futureVersion = version::Version::getFutureMajorLanguageVersion();
+      if (!anchor->hasCurriedSelf() || ctx.isSwiftVersionAtLeast(futureVersion))
+        return Type();
+
+      diag.warnUntilFutureSwiftVersion();
     }
   }
 
@@ -676,9 +718,9 @@ Type TypeChecker::typeCheckParameterDefault(Expr *&defaultValue,
       cs.openGenericRequirement(DC->getParent(), signature, index, requirement,
                                 /*skipSelfProtocolConstraint=*/false, locator,
                                 [&](Type type) -> Type {
-                                  return cs.openType(type, genericParameters,
-                                                     locator);
-                                });
+                                  return cs.openType(type, genericParameters, locator,
+                                                     /*preparedOverload=*/nullptr);
+                                }, /*preparedOverload=*/nullptr);
     };
 
     auto diagnoseInvalidRequirement = [&](Requirement requirement) {
@@ -808,30 +850,8 @@ bool TypeChecker::typeCheckBinding(Pattern *&pattern, Expr *&initializer,
     return false;
   }
 
-  auto &Context = DC->getASTContext();
   initializer = target.getAsExpr();
-
-  if (!initializer->getType())
-    initializer->setType(ErrorType::get(Context));
-
-  // Assign error types to the pattern and its variables, to prevent it from
-  // being referenced by the constraint system.
-  if (patternType->hasUnresolvedType() ||
-      patternType->hasPlaceholder() ||
-      patternType->hasUnboundGenericType()) {
-    pattern->setType(ErrorType::get(Context));
-  }
-
-  pattern->forEachVariable([&](VarDecl *var) {
-    // Don't change the type of a variable that we've been able to
-    // compute a type for.
-    if (var->hasInterfaceType() &&
-        !var->getTypeInContext()->hasUnboundGenericType() &&
-        !var->isInvalid())
-      return;
-
-    var->setInvalid();
-  });
+  pattern = target.getInitializationPattern();
   return true;
 }
 
@@ -854,11 +874,6 @@ bool TypeChecker::typeCheckPatternBinding(PatternBindingDecl *PBD,
       auto contextualPattern = ContextualPattern::forRawPattern(pattern, DC);
       patternType = typeCheckPattern(contextualPattern);
     }
-
-    if (patternType->hasError()) {
-      PBD->setInvalid();
-      return true;
-    }
   }
 
   bool hadError = TypeChecker::typeCheckBinding(pattern, init, DC, patternType,
@@ -878,44 +893,36 @@ bool TypeChecker::typeCheckPatternBinding(PatternBindingDecl *PBD,
   return hadError;
 }
 
-bool TypeChecker::typeCheckForEachPreamble(DeclContext *dc, ForEachStmt *stmt) {
+bool TypeChecker::typeCheckForEachPreamble(DeclContext *dc, ForEachStmt *stmt,
+                                           bool skipWhere) {
   auto &Context = dc->getASTContext();
   FrontendStatsTracer statsTracer(Context.Stats, "typecheck-for-each", stmt);
   PrettyStackTraceStmt stackTrace(Context, "type-checking-for-each", stmt);
 
-  auto failed = [&]() -> bool {
-    // Invalidate the pattern and the var decl.
-    stmt->getPattern()->setType(ErrorType::get(Context));
-    stmt->getPattern()->forEachVariable([&](VarDecl *var) {
-      if (var->hasInterfaceType() && !var->isInvalid())
-        return;
-      var->setInvalid();
-    });
-    return true;
-  };
-
   auto target = SyntacticElementTarget::forForEachPreamble(stmt, dc);
   if (!typeCheckTarget(target))
-    return failed();
+    return true;
 
-  if (auto *where = stmt->getWhere()) {
-    auto boolType = dc->getASTContext().getBoolType();
-    if (!boolType)
-      return failed();
+  if (!skipWhere) {
+    if (auto *where = stmt->getWhere()) {
+      auto boolType = dc->getASTContext().getBoolType();
+      if (!boolType)
+        return true;
 
-    SyntacticElementTarget whereClause(where, dc, {boolType, CTP_Condition},
-                                       /*isDiscarded=*/false);
-    auto result = typeCheckTarget(whereClause);
-    if (!result)
-      return true;
+      SyntacticElementTarget whereClause(where, dc, {boolType, CTP_Condition},
+                                         /*isDiscarded=*/false);
+      auto result = typeCheckTarget(whereClause);
+      if (!result)
+        return true;
 
-    stmt->setWhere(result->getAsExpr());
+      stmt->setWhere(result->getAsExpr());
+    }
   }
 
   // Check to see if the sequence expr is throwing (in async context),
   // if so require the stmt to have a `try`.
   if (diagnoseUnhandledThrowsInAsyncContext(dc, stmt))
-    return failed();
+    return true;
 
   return false;
 }
@@ -1055,8 +1062,14 @@ bool TypeChecker::typesSatisfyConstraint(Type type1, Type type2,
                                          bool openArchetypes,
                                          ConstraintKind kind, DeclContext *dc,
                                          bool *unwrappedIUO) {
-  assert(!type1->hasTypeVariable() && !type2->hasTypeVariable() &&
-         "Unexpected type variable in constraint satisfaction testing");
+  // Don't allow any type variables to leak into the nested ConstraintSystem
+  // (including as originator types for placeholders). This also ensure that we
+  // avoid lifetime issues for e.g cases where we lazily populate the
+  // `ContextSubMap` on `NominalOrBoundGenericNominalType` in the nested arena,
+  // since it will be destroyed on leaving.
+  ASSERT(!type1->getRecursiveProperties().isSolverAllocated() &&
+         !type2->getRecursiveProperties().isSolverAllocated() &&
+         "Cannot escape solver-allocated types into a nested ConstraintSystem");
 
   ConstraintSystem cs(dc, ConstraintSystemOptions());
   if (openArchetypes) {
@@ -1259,8 +1272,7 @@ TypeChecker::coerceToRValue(ASTContext &Context, Expr *expr,
 
 void OverloadChoice::dump(Type adjustedOpenedType, SourceManager *sm,
                           raw_ostream &out) const {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
+  PrintOptions PO = PrintOptions::forDebugging();
   out << " with ";
 
   switch (getKind()) {
@@ -1305,8 +1317,7 @@ void OverloadChoice::dump(Type adjustedOpenedType, SourceManager *sm,
 void Solution::dump() const { dump(llvm::errs(), 0); }
 
 void Solution::dump(raw_ostream &out, unsigned indent) const {
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
+  PrintOptions PO = PrintOptions::forDebugging();
 
   SourceManager *sm = &getConstraintSystem().getASTContext().SourceMgr;
 
@@ -1481,8 +1492,7 @@ void ConstraintSystem::print(raw_ostream &out, Expr *E) const {
 
 void ConstraintSystem::print(raw_ostream &out) const {
   // Print all type variables as $T0 instead of _ here.
-  PrintOptions PO;
-  PO.PrintTypesForDebugging = true;
+  PrintOptions PO = PrintOptions::forDebugging();
 
   auto indent = solverState ? solverState->getCurrentIndent() : 0;
   out.indent(indent) << "Score:";
@@ -1860,8 +1870,8 @@ TypeChecker::typeCheckCheckedCast(Type fromType, Type toType,
   };
 
   // Check for casts between specific concrete types that cannot succeed.
-  if (auto toElementType = toType->isArrayType()) {
-    if (auto fromElementType = fromType->isArrayType()) {
+  if (auto toElementType = toType->getArrayElementType()) {
+    if (auto fromElementType = fromType->getArrayElementType()) {
       return checkElementCast(fromElementType, toElementType,
                               CheckedCastKind::ArrayDowncast);
     }
@@ -2417,3 +2427,11 @@ void ConstraintSystem::forEachExpr(
 
   expr->walk(ChildWalker(*this, callback));
 }
+
+bool ModuleHasTypeCheckerPerformanceHacksEnabledRequest::evaluate(
+    Evaluator &evaluator, const ModuleDecl *module) const {
+  auto name = module->getRealName().str();
+  return module->getASTContext().blockListConfig.hasBlockListAction(
+      name, BlockListKeyKind::ModuleName,
+      BlockListAction::ShouldUseTypeCheckerPerfHacks);
+}
diff --git a/lib/Sema/TypeCheckDecl.cpp b/lib/Sema/TypeCheckDecl.cpp
index 32bea59fd1200..38b5e6f246f9f 100644
--- a/lib/Sema/TypeCheckDecl.cpp
+++ b/lib/Sema/TypeCheckDecl.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -16,7 +16,7 @@
 
 #include "TypeCheckDecl.h"
 #include "CodeSynthesis.h"
-#include "DerivedConformances.h"
+#include "DerivedConformance/DerivedConformance.h"
 #include "MiscDiagnostics.h"
 #include "TypeCheckAccess.h"
 #include "TypeCheckAvailability.h"
@@ -390,6 +390,9 @@ static bool doesAccessorNeedDynamicAttribute(AccessorDecl *accessor) {
     return false;
   case AccessorKind::Init:
     return false;
+  case AccessorKind::Borrow:
+  case AccessorKind::Mutate:
+    return false;
   }
   llvm_unreachable("covered switch");
 }
@@ -876,7 +879,9 @@ IsFinalRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
           case AccessorKind::Modify:
           case AccessorKind::Get:
           case AccessorKind::DistributedGet:
-          case AccessorKind::Set: {
+          case AccessorKind::Set:
+          case AccessorKind::Borrow:
+          case AccessorKind::Mutate: {
             // Coroutines and accessors are final if their storage is.
             auto storage = accessor->getStorage();
             if (storage->isFinal())
@@ -1304,15 +1309,6 @@ EnumRawValuesRequest::evaluate(Evaluator &eval, EnumDecl *ED,
     SourceLoc diagLoc = uncheckedRawValueOf(elt)->isImplicit()
                             ? elt->getLoc()
                             : uncheckedRawValueOf(elt)->getLoc();
-    if (auto magicLiteralExpr =
-            dyn_cast<MagicIdentifierLiteralExpr>(prevValue)) {
-      auto kindString =
-          magicLiteralExpr->getKindString(magicLiteralExpr->getKind());
-      Diags.diagnose(diagLoc, diag::enum_raw_value_magic_literal, kindString);
-      elt->setInvalid();
-      continue;
-    }
-
     // Check that the raw value is unique.
     RawValueKey key{prevValue};
     RawValueSource source{elt, lastExplicitValueElt};
@@ -1654,6 +1650,7 @@ SelfAccessKindRequest::evaluate(Evaluator &evaluator, FuncDecl *FD) const {
     case AccessorKind::DistributedGet:
     case AccessorKind::Read:
     case AccessorKind::Read2:
+    case AccessorKind::Borrow:
       break;
 
     case AccessorKind::Init:
@@ -1661,6 +1658,7 @@ SelfAccessKindRequest::evaluate(Evaluator &evaluator, FuncDecl *FD) const {
     case AccessorKind::Set:
     case AccessorKind::Modify:
     case AccessorKind::Modify2:
+    case AccessorKind::Mutate:
       if (AD->isInstanceMember() && AD->getDeclContext()->hasValueSemantics())
         return SelfAccessKind::Mutating;
       break;
@@ -1679,72 +1677,6 @@ SelfAccessKindRequest::evaluate(Evaluator &evaluator, FuncDecl *FD) const {
   return SelfAccessKind::NonMutating;
 }
 
-bool TypeChecker::isAvailabilitySafeForConformance(
-    const ProtocolDecl *proto, const ValueDecl *requirement,
-    const ValueDecl *witness, const DeclContext *dc,
-    AvailabilityRange &requirementInfo) {
-
-  // We assume conformances in
-  // non-SourceFiles have already been checked for availability.
-  if (!dc->getParentSourceFile())
-    return true;
-
-  auto &Context = proto->getASTContext();
-  assert(dc->getSelfNominalTypeDecl() &&
-         "Must have a nominal or extension context");
-
-  auto contextForConformingDecl =
-      AvailabilityContext::forDeclSignature(dc->getAsDecl());
-
-  // If the conformance is unavailable then it's irrelevant whether the witness
-  // is potentially unavailable.
-  if (contextForConformingDecl.isUnavailable())
-    return true;
-
-  // Make sure that any access of the witness through the protocol
-  // can only occur when the witness is available. That is, make sure that
-  // on every version where the conforming declaration is available, if the
-  // requirement is available then the witness is available as well.
-  // We do this by checking that (an over-approximation of) the intersection of
-  // the requirement's available range with both the conforming declaration's
-  // available range and the protocol's available range is fully contained in
-  // (an over-approximation of) the intersection of the witnesses's available
-  // range with both the conforming type's available range and the protocol
-  // declaration's available range.
-  AvailabilityRange witnessInfo =
-      AvailabilityInference::availableRange(witness);
-  requirementInfo = AvailabilityInference::availableRange(requirement);
-
-  AvailabilityRange infoForConformingDecl =
-      contextForConformingDecl.getPlatformRange();
-
-  // Relax the requirements for @_spi witnesses by treating the requirement as
-  // if it were introduced at the deployment target. This is not strictly sound
-  // since clients of SPI do not necessarily have the same deployment target as
-  // the module declaring the requirement. However, now that the public
-  // declarations in API libraries are checked according to the minimum possible
-  // deployment target of their clients this relaxation is needed for source
-  // compatibility with some existing code and is reasonably safe for the
-  // majority of cases.
-  if (witness->isSPI()) {
-    AvailabilityRange deploymentTarget =
-        AvailabilityRange::forDeploymentTarget(Context);
-    requirementInfo.constrainWith(deploymentTarget);
-  }
-
-  // Constrain over-approximates intersection of version ranges.
-  witnessInfo.constrainWith(infoForConformingDecl);
-  requirementInfo.constrainWith(infoForConformingDecl);
-
-  AvailabilityRange infoForProtocolDecl =
-      AvailabilityContext::forDeclSignature(proto).getPlatformRange();
-
-  witnessInfo.constrainWith(infoForProtocolDecl);
-  requirementInfo.constrainWith(infoForProtocolDecl);
-
-  return requirementInfo.isContainedIn(witnessInfo);
-}
-
 // Returns 'nullptr' if this is the 'newValue' or 'oldValue' parameter;
 // otherwise, returns the corresponding parameter of the subscript
 // declaration.
@@ -2116,6 +2048,7 @@ ResultTypeRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
     // For getters, set the result type to the value type.
     case AccessorKind::Get:
     case AccessorKind::DistributedGet:
+    case AccessorKind::Borrow:
       return storage->getValueInterfaceType();
 
     // For setters and observers, set the old/new value parameter's type
@@ -2126,6 +2059,9 @@ ResultTypeRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
     case AccessorKind::Init:
       return TupleType::getEmpty(ctx);
 
+    case AccessorKind::Mutate:
+      return storage->getValueInterfaceType();
+
     // Addressor result types can get complicated because of the owner.
     case AccessorKind::Address:
     case AccessorKind::MutableAddress:
@@ -2187,7 +2123,7 @@ ResultTypeRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
   auto *const dc = decl->getInnermostDeclContext();
   return TypeResolution::forInterface(dc, options,
                                       /*unboundTyOpener*/ nullptr,
-                                      PlaceholderType::get,
+                                      /*placeholderOpener*/ nullptr,
                                       /*packElementOpener*/ nullptr)
       .resolveType(resultTyRepr);
 }
@@ -2248,13 +2184,20 @@ ParamSpecifierRequest::evaluate(Evaluator &evaluator,
 
   auto typeRepr = param->getTypeRepr();
 
-  if (!typeRepr && !param->isImplicit()) {
-    // Untyped closure parameter.
-    return ParamSpecifier::Default;
-  }
+  if (!typeRepr) {
+    if (!param->isImplicit()) {
+      // Untyped closure parameter.
+      return ParamSpecifier::Default;
+    }
+
+    if (param->isInvalid()) {
+      // Invalid parse.
+      return ParamSpecifier::Default;
+    }
 
-  assert(typeRepr != nullptr && "Should call setSpecifier() on "
-         "synthesized parameter declarations");
+    ASSERT(false && "Should call setSpecifier() on "
+           "synthesized parameter declarations");
+  }
 
   // Look through top-level pack expansions.  These specifiers are
   // part of what's repeated.
@@ -2272,6 +2215,10 @@ ParamSpecifierRequest::evaluate(Evaluator &evaluator,
     nestedRepr = lifetime->getBase();
   }
 
+  if (auto callerIsolated = dyn_cast<CallerIsolatedTypeRepr>(nestedRepr)) {
+    nestedRepr = callerIsolated->getBase();
+  }
+
   if (auto sending = dyn_cast<SendingTypeRepr>(nestedRepr)) {
     // If we do not have an Ownership Repr and do not have a no escape type,
     // return implicit copyable consuming.
@@ -2294,7 +2241,7 @@ ParamSpecifierRequest::evaluate(Evaluator &evaluator,
     }
     return ownershipRepr->getSpecifier();
   }
-  
+
   return ParamSpecifier::Default;
 }
 
@@ -2304,6 +2251,7 @@ static Type validateParameterType(ParamDecl *decl) {
 
   TypeResolutionOptions options(std::nullopt);
   OpenUnboundGenericTypeFn unboundTyOpener = nullptr;
+  HandlePlaceholderTypeReprFn placeholderOpener = nullptr;
   if (isa<AbstractClosureExpr>(dc)) {
     options = TypeResolutionOptions(TypeResolverContext::ClosureExpr);
     options |= TypeResolutionFlags::AllowUnspecifiedTypes;
@@ -2312,8 +2260,9 @@ static Type validateParameterType(ParamDecl *decl) {
       // For now, just return the unbound generic type.
       return unboundTy;
     };
-    // FIXME: Don't let placeholder types escape type resolution.
-    // For now, just return the placeholder type.
+    // FIXME: Don't let placeholder types escape type resolution. For now, just
+    // return the placeholder type, which we open in `inferClosureType`.
+    placeholderOpener = PlaceholderType::get;
   } else if (isa<AbstractFunctionDecl>(dc)) {
     options = TypeResolutionOptions(TypeResolverContext::AbstractFunctionDecl);
   } else if (isa<SubscriptDecl>(dc)) {
@@ -2364,7 +2313,7 @@ static Type validateParameterType(ParamDecl *decl) {
 
   const auto resolution =
       TypeResolution::forInterface(dc, options, unboundTyOpener,
-                                   PlaceholderType::get,
+                                   placeholderOpener,
                                    /*packElementOpener*/ nullptr);
 
   if (isa<VarargTypeRepr>(nestedRepr)) {
@@ -2405,6 +2354,13 @@ static void maybeAddParameterIsolation(AnyFunctionType::ExtInfoBuilder &infoBuil
     infoBuilder = infoBuilder.withIsolation(FunctionTypeIsolation::forParameter());
 }
 
+std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>
+getLifetimeDependencies(ASTContext &context, EnumElementDecl *enumElemDecl) {
+  return evaluateOrDefault(context.evaluator,
+                           LifetimeDependenceInfoRequest{enumElemDecl},
+                           std::nullopt);
+}
+
 Type
 InterfaceTypeRequest::evaluate(Evaluator &eval, ValueDecl *D) const {
   auto &Context = D->getASTContext();
@@ -2426,6 +2382,7 @@ InterfaceTypeRequest::evaluate(Evaluator &eval, ValueDecl *D) const {
   case DeclKind::Module:
   case DeclKind::OpaqueType:
   case DeclKind::MacroExpansion:
+  case DeclKind::Using:
     llvm_unreachable("should not get here");
     return Type();
 
@@ -2633,7 +2590,10 @@ InterfaceTypeRequest::evaluate(Evaluator &eval, ValueDecl *D) const {
         selfInfoBuilder =
             selfInfoBuilder.withLifetimeDependencies(*lifetimeDependenceInfo);
       }
-
+      auto *accessor = dyn_cast<AccessorDecl>(AFD);
+      if (accessor && accessor->isMutateAccessor()) {
+        selfInfoBuilder = selfInfoBuilder.withHasInOutResult();
+      }
       // FIXME: Verify ExtInfo state is correct, not working by accident.
       auto selfInfo = selfInfoBuilder.build();
       if (sig) {
@@ -2693,13 +2653,25 @@ InterfaceTypeRequest::evaluate(Evaluator &eval, ValueDecl *D) const {
       resultTy = FunctionType::get(argTy, resultTy, info);
     }
 
+    auto lifetimeDependenceInfo = getLifetimeDependencies(Context, EED);
+
     // FIXME: Verify ExtInfo state is correct, not working by accident.
     if (auto genericSig = ED->getGenericSignature()) {
-      GenericFunctionType::ExtInfo info;
-      resultTy = GenericFunctionType::get(genericSig, {selfTy}, resultTy, info);
+      GenericFunctionType::ExtInfoBuilder infoBuilder;
+      if (lifetimeDependenceInfo.has_value()) {
+        infoBuilder =
+            infoBuilder.withLifetimeDependencies(*lifetimeDependenceInfo);
+      }
+      resultTy = GenericFunctionType::get(genericSig, {selfTy}, resultTy,
+                                          infoBuilder.build());
+
     } else {
-      FunctionType::ExtInfo info;
-      resultTy = FunctionType::get({selfTy}, resultTy, info);
+      FunctionType::ExtInfoBuilder infoBuilder;
+      if (lifetimeDependenceInfo.has_value()) {
+        infoBuilder =
+            infoBuilder.withLifetimeDependencies(*lifetimeDependenceInfo);
+      }
+      resultTy = FunctionType::get({selfTy}, resultTy, infoBuilder.build());
     }
 
     return resultTy;
@@ -2759,7 +2731,7 @@ NamingPatternRequest::evaluate(Evaluator &evaluator, VarDecl *VD) const {
   }
 
   if (!namingPattern) {
-    if (auto parentStmt = VD->getParentPatternStmt()) {
+    if (auto parentStmt = VD->getRecursiveParentPatternStmt()) {
       // Try type checking parent control statement.
       if (auto condStmt = dyn_cast<LabeledConditionalStmt>(parentStmt)) {
         // The VarDecl is defined inside a condition of a `if` or `while` stmt.
@@ -2929,7 +2901,7 @@ static ArrayRef<Decl *> evaluateMembersRequest(
     }
   }
 
-  if (nominal) {
+  if (nominal && !isa<ProtocolDecl>(nominal)) {
     // If the type conforms to Encodable or Decodable, even via an extension,
     // the CodingKeys enum is synthesized as a member of the type itself.
     // Force it into existence.
@@ -3058,9 +3030,11 @@ bool TypeChecker::isPassThroughTypealias(TypeAliasDecl *typealias,
 
 Type
 ExtendedTypeRequest::evaluate(Evaluator &eval, ExtensionDecl *ext) const {
-  auto error = [&ext]() {
+  auto &ctx = ext->getASTContext();
+
+  auto error = [&]() {
     ext->setInvalid();
-    return ErrorType::get(ext->getASTContext());
+    return ErrorType::get(ctx);
   };
 
   // If we didn't parse a type, fill in an error type and bail out.
@@ -3072,7 +3046,7 @@ ExtendedTypeRequest::evaluate(Evaluator &eval, ExtensionDecl *ext) const {
   TypeResolutionOptions options(TypeResolverContext::ExtensionBinding);
   if (ext->isInSpecializeExtensionContext())
     options |= TypeResolutionFlags::AllowUsableFromInline;
-  const auto resolution = TypeResolution::forStructural(
+  const auto resolution = TypeResolution::forInterface(
       ext->getDeclContext(), options, nullptr,
       // FIXME: Don't let placeholder types escape type resolution.
       // For now, just return the placeholder type.
@@ -3084,6 +3058,15 @@ ExtendedTypeRequest::evaluate(Evaluator &eval, ExtensionDecl *ext) const {
   if (extendedType->hasError())
     return error();
 
+  auto &diags = ctx.Diags;
+
+  // Cannot extend types who contain placeholders.
+  if (extendedType->hasPlaceholder()) {
+    diags.diagnose(ext->getLoc(), diag::extension_placeholder)
+      .highlight(extendedRepr->getSourceRange());
+    return error();
+  }
+
   // Hack to allow extending a generic typealias.
   if (auto *unboundGeneric = extendedType->getAs<UnboundGenericType>()) {
     if (auto *aliasDecl = dyn_cast<TypeAliasDecl>(unboundGeneric->getDecl())) {
@@ -3101,8 +3084,6 @@ ExtendedTypeRequest::evaluate(Evaluator &eval, ExtensionDecl *ext) const {
     }
   }
 
-  auto &diags = ext->getASTContext().Diags;
-
   // Cannot extend a metatype.
   if (extendedType->is<AnyMetatypeType>()) {
     diags.diagnose(ext->getLoc(), diag::extension_metatype, extendedType)
@@ -3110,6 +3091,13 @@ ExtendedTypeRequest::evaluate(Evaluator &eval, ExtensionDecl *ext) const {
     return error();
   }
 
+  // Tuple extensions are experimental.
+  if (extendedType->is<TupleType>() &&
+      !ctx.LangOpts.hasFeature(Feature::TupleConformances)) {
+    diags.diagnose(ext, diag::experimental_tuple_extension);
+    return error();
+  }
+
   // Cannot extend function types, metatypes, existentials, etc.
   if (!extendedType->is<TupleType>() &&
       !extendedType->getAnyNominal() &&
@@ -3119,13 +3107,6 @@ ExtendedTypeRequest::evaluate(Evaluator &eval, ExtensionDecl *ext) const {
     return error();
   }
 
-  // Cannot extend types who contain placeholders.
-  if (extendedType->hasPlaceholder()) {
-    diags.diagnose(ext->getLoc(), diag::extension_placeholder)
-      .highlight(extendedRepr->getSourceRange());
-    return error();
-  }
-
   return extendedType;
 }
 
@@ -3148,7 +3129,7 @@ ImplicitKnownProtocolConformanceRequest::evaluate(Evaluator &evaluator,
 
 std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>
 LifetimeDependenceInfoRequest::evaluate(Evaluator &evaluator,
-                                        AbstractFunctionDecl *decl) const {
+                                        ValueDecl *decl) const {
   return LifetimeDependenceInfo::get(decl);
 }
 
diff --git a/lib/Sema/TypeCheckDeclObjC.cpp b/lib/Sema/TypeCheckDeclObjC.cpp
index ec38710102b22..ea76a0fcb986e 100644
--- a/lib/Sema/TypeCheckDeclObjC.cpp
+++ b/lib/Sema/TypeCheckDeclObjC.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -19,7 +19,7 @@
 #include "TypeCheckProtocol.h"
 #include "TypeChecker.h"
 #include "swift/AST/ASTContext.h"
-#include "swift/AST/AvailabilityInference.h"
+#include "swift/AST/ASTPrinter.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/ExistentialLayout.h"
 #include "swift/AST/ForeignErrorConvention.h"
@@ -48,6 +48,7 @@ swift::behaviorLimitForObjCReason(ObjCReason reason, ASTContext &ctx) {
     LLVM_FALLTHROUGH;
 
   case ObjCReason::ExplicitlyCDecl:
+  case ObjCReason::ExplicitlyUnderscoreCDecl:
   case ObjCReason::ExplicitlyDynamic:
   case ObjCReason::ExplicitlyObjC:
   case ObjCReason::ExplicitlyObjCMembers:
@@ -81,6 +82,7 @@ swift::behaviorLimitForObjCReason(ObjCReason reason, ASTContext &ctx) {
 unsigned swift::getObjCDiagnosticAttrKind(ObjCReason reason) {
   switch (reason) {
   case ObjCReason::ExplicitlyCDecl:
+  case ObjCReason::ExplicitlyUnderscoreCDecl:
   case ObjCReason::ExplicitlyDynamic:
   case ObjCReason::ExplicitlyObjC:
   case ObjCReason::ExplicitlyObjCMembers:
@@ -132,6 +134,7 @@ void ObjCReason::describe(const Decl *D) const {
 
   case ObjCReason::ExplicitlyObjCByAccessNote:
   case ObjCReason::ExplicitlyCDecl:
+  case ObjCReason::ExplicitlyUnderscoreCDecl:
   case ObjCReason::ExplicitlyDynamic:
   case ObjCReason::ExplicitlyObjC:
   case ObjCReason::ExplicitlyObjCMembers:
@@ -166,17 +169,19 @@ void ObjCReason::setAttrInvalid() const {
 static void diagnoseTypeNotRepresentableInObjC(const DeclContext *DC,
                                                Type T,
                                                SourceRange TypeRange,
-                                               DiagnosticBehavior behavior) {
+                                               DiagnosticBehavior behavior,
+                                               ObjCReason reason) {
   auto &diags = DC->getASTContext().Diags;
+  auto language = reason.getForeignLanguage();
 
   // Special diagnostic for tuples.
   if (T->is<TupleType>()) {
     if (T->isVoid())
-      diags.diagnose(TypeRange.Start, diag::not_objc_empty_tuple)
+      diags.diagnose(TypeRange.Start, diag::not_objc_empty_tuple, language)
           .highlight(TypeRange)
           .limitBehavior(behavior);
     else
-      diags.diagnose(TypeRange.Start, diag::not_objc_tuple)
+      diags.diagnose(TypeRange.Start, diag::not_objc_tuple, language)
           .highlight(TypeRange)
           .limitBehavior(behavior);
     return;
@@ -184,6 +189,13 @@ static void diagnoseTypeNotRepresentableInObjC(const DeclContext *DC,
 
   // Special diagnostic for classes.
   if (auto *CD = T->getClassOrBoundGenericClass()) {
+    if (language == ForeignLanguage::C) {
+      diags.diagnose(TypeRange.Start, diag::cdecl_incompatible_with_classes)
+          .highlight(TypeRange)
+          .limitBehavior(behavior);
+      return;
+    }
+
     if (!CD->isObjC())
       diags.diagnose(TypeRange.Start, diag::not_objc_swift_class)
           .highlight(TypeRange)
@@ -195,12 +207,14 @@ static void diagnoseTypeNotRepresentableInObjC(const DeclContext *DC,
   if (auto *SD = T->getStructOrBoundGenericStruct()) {
     if (isa_and_nonnull<clang::CXXRecordDecl>(SD->getClangDecl())) {
       // This can be a non-trivial C++ record.
-      diags.diagnose(TypeRange.Start, diag::not_objc_non_trivial_cxx_class)
+      diags.diagnose(TypeRange.Start, diag::not_objc_non_trivial_cxx_class,
+                     language)
           .highlight(TypeRange)
           .limitBehavior(behavior);
       return;
     }
-    diags.diagnose(TypeRange.Start, diag::not_objc_swift_struct)
+    diags.diagnose(TypeRange.Start, diag::not_objc_swift_struct,
+                   language)
         .highlight(TypeRange)
         .limitBehavior(behavior);
     return;
@@ -208,14 +222,30 @@ static void diagnoseTypeNotRepresentableInObjC(const DeclContext *DC,
 
   // Special diagnostic for enums.
   if (T->is<EnumType>()) {
-    diags.diagnose(TypeRange.Start, diag::not_objc_swift_enum)
-        .highlight(TypeRange)
-        .limitBehavior(behavior);
+    if (DC->getASTContext().LangOpts.hasFeature(Feature::CDecl)) {
+      // New dialog mentioning @c.
+      diags.diagnose(TypeRange.Start, diag::not_cdecl_or_objc_swift_enum,
+                     language)
+          .highlight(TypeRange)
+          .limitBehavior(behavior);
+    } else {
+      diags.diagnose(TypeRange.Start, diag::not_objc_swift_enum)
+          .highlight(TypeRange)
+          .limitBehavior(behavior);
+    }
     return;
   }
 
   // Special diagnostic for protocols and protocol compositions.
   if (T->isExistentialType()) {
+    // No protocol is representable in C.
+    if (language == ForeignLanguage::C) {
+      diags.diagnose(TypeRange.Start, diag::cdecl_incompatible_with_protocols)
+          .highlight(TypeRange)
+          .limitBehavior(behavior);
+      return;
+    }
+
     if (T->isAny()) {
       // Any is not @objc.
       diags.diagnose(TypeRange.Start,
@@ -263,7 +293,8 @@ static void diagnoseTypeNotRepresentableInObjC(const DeclContext *DC,
   }
 
   if (T->is<ArchetypeType>() || T->isTypeParameter()) {
-    diags.diagnose(TypeRange.Start, diag::not_objc_generic_type_param)
+    diags.diagnose(TypeRange.Start, diag::not_objc_generic_type_param,
+                   language)
         .highlight(TypeRange)
         .limitBehavior(behavior);
     return;
@@ -271,20 +302,23 @@ static void diagnoseTypeNotRepresentableInObjC(const DeclContext *DC,
 
   if (auto fnTy = T->getAs<FunctionType>()) {
     if (fnTy->getExtInfo().isAsync()) {
-      diags.diagnose(TypeRange.Start, diag::not_objc_function_type_async)
+      diags.diagnose(TypeRange.Start, diag::not_objc_function_type_async,
+                     language)
         .highlight(TypeRange)
         .limitBehavior(behavior);
       return;
     }
 
     if (fnTy->getExtInfo().isThrowing()) {
-      diags.diagnose(TypeRange.Start, diag::not_objc_function_type_throwing)
+      diags.diagnose(TypeRange.Start, diag::not_objc_function_type_throwing,
+                     language)
         .highlight(TypeRange)
         .limitBehavior(behavior);
       return;
     }
 
-    diags.diagnose(TypeRange.Start, diag::not_objc_function_type_param)
+    diags.diagnose(TypeRange.Start, diag::not_objc_function_type_param,
+                   language)
       .highlight(TypeRange)
       .limitBehavior(behavior);
     return;
@@ -295,16 +329,19 @@ static void diagnoseFunctionParamNotRepresentable(
     const AbstractFunctionDecl *AFD, unsigned NumParams,
     unsigned ParamIndex, const ParamDecl *P, ObjCReason Reason) {
   auto behavior = behaviorLimitForObjCReason(Reason, AFD->getASTContext());
+  auto language = Reason.getForeignLanguage();
 
   if (NumParams == 1) {
     softenIfAccessNote(AFD, Reason.getAttr(),
       AFD->diagnose(diag::objc_invalid_on_func_single_param_type,
-                    getObjCDiagnosticAttrKind(Reason))
+                    AFD, getObjCDiagnosticAttrKind(Reason),
+                    language)
           .limitBehavior(behavior));
   } else {
     softenIfAccessNote(AFD, Reason.getAttr(),
       AFD->diagnose(diag::objc_invalid_on_func_param_type,
-                    ParamIndex + 1, getObjCDiagnosticAttrKind(Reason))
+                    AFD, ParamIndex + 1, getObjCDiagnosticAttrKind(Reason),
+                    language)
           .limitBehavior(behavior));
   }
   SourceRange SR;
@@ -312,22 +349,24 @@ static void diagnoseFunctionParamNotRepresentable(
   if (P->hasAttachedPropertyWrapper()) {
     auto wrapperTy = P->getPropertyWrapperBackingPropertyType();
     SR = P->getOutermostAttachedPropertyWrapper()->getRange();
-    diagnoseTypeNotRepresentableInObjC(AFD, wrapperTy, SR, behavior);
+    diagnoseTypeNotRepresentableInObjC(AFD, wrapperTy, SR, behavior, Reason);
   } else {
     if (auto typeRepr = P->getTypeRepr())
       SR = typeRepr->getSourceRange();
-    diagnoseTypeNotRepresentableInObjC(AFD, P->getTypeInContext(), SR, behavior);
+    diagnoseTypeNotRepresentableInObjC(AFD, P->getTypeInContext(), SR,
+                                       behavior, Reason);
   }
   Reason.describe(AFD);
 }
 
-static bool isParamListRepresentableInObjC(const AbstractFunctionDecl *AFD,
-                                           const ParameterList *PL,
-                                           ObjCReason Reason) {
+static bool isParamListRepresentableInLanguage(const AbstractFunctionDecl *AFD,
+                                               const ParameterList *PL,
+                                               ObjCReason Reason) {
   // If you change this function, you must add or modify a test in PrintAsClang.
   ASTContext &ctx = AFD->getASTContext();
   auto &diags = ctx.Diags;
   auto behavior = behaviorLimitForObjCReason(Reason, ctx);
+  auto language = Reason.getForeignLanguage();
   bool IsObjC = true;
   unsigned NumParams = PL->size();
   for (unsigned ParamIndex = 0; ParamIndex != NumParams; ++ParamIndex) {
@@ -337,7 +376,7 @@ static bool isParamListRepresentableInObjC(const AbstractFunctionDecl *AFD,
     if (param->isVariadic()) {
       softenIfAccessNote(AFD, Reason.getAttr(),
         diags.diagnose(param->getStartLoc(), diag::objc_invalid_on_func_variadic,
-                       getObjCDiagnosticAttrKind(Reason))
+                       AFD, getObjCDiagnosticAttrKind(Reason))
           .highlight(param->getSourceRange())
           .limitBehavior(behavior));
       Reason.describe(AFD);
@@ -349,7 +388,8 @@ static bool isParamListRepresentableInObjC(const AbstractFunctionDecl *AFD,
     if (param->isInOut()) {
       softenIfAccessNote(AFD, Reason.getAttr(),
         diags.diagnose(param->getStartLoc(), diag::objc_invalid_on_func_inout,
-                       getObjCDiagnosticAttrKind(Reason))
+                       AFD, getObjCDiagnosticAttrKind(Reason),
+                       language)
           .highlight(param->getSourceRange())
           .limitBehavior(behavior));
       Reason.describe(AFD);
@@ -362,11 +402,11 @@ static bool isParamListRepresentableInObjC(const AbstractFunctionDecl *AFD,
 
     if (param->hasAttachedPropertyWrapper()) {
       if (param->getPropertyWrapperBackingPropertyType()->isRepresentableIn(
-          ForeignLanguage::ObjectiveC,
+          language,
           const_cast<AbstractFunctionDecl *>(AFD)))
         continue;
     } else if (param->getTypeInContext()->isRepresentableIn(
-          ForeignLanguage::ObjectiveC,
+          language,
           const_cast<AbstractFunctionDecl *>(AFD))) {
       continue;
     }
@@ -401,19 +441,20 @@ static bool checkObjCWithGenericParams(const ValueDecl *VD, ObjCReason Reason) {
   assert(GC);
   if (GC->getGenericParams()) {
     softenIfAccessNote(VD, Reason.getAttr(),
-      VD->diagnose(diag::objc_invalid_with_generic_params,
-                   VD->getDescriptiveKind(), getObjCDiagnosticAttrKind(Reason))
-          .limitBehavior(behavior));
+                       VD->diagnose(diag::objc_invalid_with_generic_params, VD,
+                                    getObjCDiagnosticAttrKind(Reason))
+                           .limitBehavior(behavior));
     Reason.describe(VD);
 
     return true;
   }
 
   if (GC->getTrailingWhereClause()) {
-    softenIfAccessNote(VD, Reason.getAttr(),
-      VD->diagnose(diag::objc_invalid_with_generic_requirements,
-                   VD->getDescriptiveKind(), getObjCDiagnosticAttrKind(Reason))
-          .limitBehavior(behavior));
+    softenIfAccessNote(
+        VD, Reason.getAttr(),
+        VD->diagnose(diag::objc_invalid_with_generic_requirements, VD,
+                     getObjCDiagnosticAttrKind(Reason))
+            .limitBehavior(behavior));
     Reason.describe(VD);
 
     return true;
@@ -448,9 +489,8 @@ static bool checkObjCInForeignClassContext(const ValueDecl *VD,
     break;
 
   case ClassDecl::ForeignKind::RuntimeOnly:
-    VD->diagnose(diag::objc_in_objc_runtime_visible,
-                 VD->getDescriptiveKind(), getObjCDiagnosticAttrKind(Reason),
-                 clazz->getName())
+    VD->diagnose(diag::objc_in_objc_runtime_visible, VD,
+                 getObjCDiagnosticAttrKind(Reason), clazz)
         .limitBehavior(behavior);
     Reason.describe(VD);
     break;
@@ -512,32 +552,30 @@ static bool checkObjCActorIsolation(const ValueDecl *VD, ObjCReason Reason) {
   }
 }
 
-static VersionRange getMinOSVersionForClassStubs(const llvm::Triple &target) {
+static AvailabilityRange getObjCClassStubAvailability(ASTContext &ctx) {
+  // FIXME: This should just be ctx.getSwift51Availability(), but that breaks
+  // tests on arm64 arches.
+  const llvm::Triple &target = ctx.LangOpts.Target;
   if (target.isMacOSX())
-    return VersionRange::allGTE(llvm::VersionTuple(10, 15, 0));
+    return AvailabilityRange(llvm::VersionTuple(10, 15, 0));
   if (target.isiOS()) // also returns true on tvOS
-    return VersionRange::allGTE(llvm::VersionTuple(13, 0, 0));
+    return AvailabilityRange(llvm::VersionTuple(13, 0, 0));
   if (target.isWatchOS())
-    return VersionRange::allGTE(llvm::VersionTuple(6, 0, 0));
+    return AvailabilityRange(llvm::VersionTuple(6, 0, 0));
   if (target.isXROS())
-    return VersionRange::allGTE(llvm::VersionTuple(1, 0, 0));
-  return VersionRange::all();
-}
-
-static AvailabilityRange getObjCClassStubAvailability(ASTContext &ctx) {
-  // FIXME: This should just be ctx.getSwift51Availability(), but that breaks
-  // tests on arm64 arches.
-  return AvailabilityRange(getMinOSVersionForClassStubs(ctx.LangOpts.Target));
+    return AvailabilityRange(llvm::VersionTuple(1, 0, 0));
+  return AvailabilityRange::alwaysAvailable();
 }
 
 static bool checkObjCClassStubAvailability(ASTContext &ctx, const Decl *decl) {
-  auto stubAvailability = getObjCClassStubAvailability(ctx);
+  auto stubAvailability = AvailabilityContext::forPlatformRange(
+      getObjCClassStubAvailability(ctx), ctx);
 
-  auto deploymentTarget = AvailabilityRange::forDeploymentTarget(ctx);
+  auto deploymentTarget = AvailabilityContext::forDeploymentTarget(ctx);
   if (deploymentTarget.isContainedIn(stubAvailability))
     return true;
 
-  auto declAvailability = AvailabilityInference::availableRange(decl);
+  auto declAvailability = AvailabilityContext::forDeclSignature(decl);
   return declAvailability.isContainedIn(stubAvailability);
 }
 
@@ -586,8 +624,7 @@ static bool checkObjCInExtensionContext(const ValueDecl *value,
           softenIfAccessNote(value, reason.getAttr(),
                              value
                                  ->diagnose(diag::objc_in_resilient_extension,
-                                            value->getDescriptiveKind(),
-                                            ancestor->getName(),
+                                            value, ancestor,
                                             ctx.getTargetAvailabilityDomain(),
                                             stubAvailability)
                                  .limitBehavior(behavior));
@@ -646,14 +683,14 @@ static bool isValidObjectiveCErrorResultType(DeclContext *dc, Type type) {
   llvm_unreachable("Unhandled ForeignRepresentableKind in switch.");
 }
 
-bool swift::isRepresentableInObjC(
+bool swift::isRepresentableInLanguage(
     const AbstractFunctionDecl *AFD, ObjCReason Reason,
     std::optional<ForeignAsyncConvention> &asyncConvention,
     std::optional<ForeignErrorConvention> &errorConvention) {
   auto abiRole = ABIRoleInfo(AFD);
   if (!abiRole.providesAPI() && abiRole.getCounterpart())
-    return isRepresentableInObjC(abiRole.getCounterpart(), Reason,
-                                 asyncConvention, errorConvention);
+    return isRepresentableInLanguage(abiRole.getCounterpart(), Reason,
+                                     asyncConvention, errorConvention);
 
   // Clear out the async and error conventions. They will be added later if
   // needed.
@@ -663,7 +700,7 @@ bool swift::isRepresentableInObjC(
   // If you change this function, you must add or modify a test in PrintAsClang.
   ASTContext &ctx = AFD->getASTContext();
   DiagnosticStateRAII diagState(ctx.Diags);
-
+  auto language = Reason.getForeignLanguage();
 
   if (checkObjCInForeignClassContext(AFD, Reason))
     return false;
@@ -689,6 +726,7 @@ bool swift::isRepresentableInObjC(
     auto storage = accessor->getStorage();
     bool storageIsObjC = storage->isObjC()
         || Reason == ObjCReason::ExplicitlyCDecl
+        || Reason == ObjCReason::ExplicitlyUnderscoreCDecl
         || Reason == ObjCReason::WitnessToObjC
         || Reason == ObjCReason::MemberOfObjCProtocol;
 
@@ -698,8 +736,7 @@ bool swift::isRepresentableInObjC(
       // willSet/didSet implementations are never exposed to objc, they are
       // always directly dispatched from the synthesized setter.
       diagnoseAndRemoveAttr(accessor, Reason.getAttr(),
-                            diag::objc_observing_accessor,
-                            accessor->getDescriptiveKind())
+                            diag::objc_observing_accessor, accessor)
           .limitBehavior(behavior);
       Reason.describe(accessor);
       return false;
@@ -739,7 +776,13 @@ bool swift::isRepresentableInObjC(
           .limitBehavior(behavior);
       Reason.describe(accessor);
       return false;
-
+    case AccessorKind::Borrow:
+    case AccessorKind::Mutate:
+      diagnoseAndRemoveAttr(accessor, Reason.getAttr(),
+                            diag::objc_borrow_mutate_accessor)
+          .limitBehavior(behavior);
+      Reason.describe(accessor);
+      return false;
     case AccessorKind::Read:
     case AccessorKind::Read2:
     case AccessorKind::Modify:
@@ -775,9 +818,9 @@ bool swift::isRepresentableInObjC(
     isSpecialInit = init->isObjCZeroParameterWithLongSelector();
 
   if (!isSpecialInit &&
-      !isParamListRepresentableInObjC(AFD,
-                                      AFD->getParameters(),
-                                      Reason)) {
+      !isParamListRepresentableInLanguage(AFD,
+                                          AFD->getParameters(),
+                                          Reason)) {
     return false;
   }
 
@@ -787,29 +830,47 @@ bool swift::isRepresentableInObjC(
         !ResultType->hasError() &&
         !ResultType->isVoid() &&
         !ResultType->isUninhabited() &&
-        !ResultType->isRepresentableIn(ForeignLanguage::ObjectiveC,
+        !ResultType->isRepresentableIn(language,
                                        const_cast<FuncDecl *>(FD))) {
       softenIfAccessNote(AFD, Reason.getAttr(),
        AFD->diagnose(diag::objc_invalid_on_func_result_type,
-                      getObjCDiagnosticAttrKind(Reason))
+                     FD, getObjCDiagnosticAttrKind(Reason),
+                     language)
             .limitBehavior(behavior));
       diagnoseTypeNotRepresentableInObjC(FD, ResultType,
                                          FD->getResultTypeSourceRange(),
-                                         behavior);
+                                         behavior, Reason);
       Reason.describe(FD);
       return false;
     }
   }
 
+  // Check that @objc functions can't have typed throw.
+  if (AFD->hasThrows()) {
+    Type thrownType = AFD->getThrownInterfaceType();
+    // TODO: only `throws(Error)` is allowed.
+    // Throwing `any MyError` that confronts `Error` is not implemented yet.
+    // Shall we allow `any MyError` in the future, we should check against
+    // `isExistentialType` instead, and other type checks will make sure it
+    // confrons to `Error`.
+    if (thrownType && !thrownType->isErrorExistentialType()) {
+      softenIfAccessNote(AFD, Reason.getAttr(),
+                         AFD->diagnose(diag::typed_throw_in_objc_forbidden, AFD)
+                             .limitBehavior(behavior));
+      Reason.describe(AFD);
+      return false;
+    }
+  }
+
   if (AFD->hasAsync()) {
     // Asynchronous functions move all of the result value and thrown error
     // information into a completion handler.
     auto FD = dyn_cast<FuncDecl>(AFD);
     if (!FD) {
       softenIfAccessNote(AFD, Reason.getAttr(),
-        AFD->diagnose(diag::not_objc_function_async, AFD->getDescriptiveKind())
-          .highlight(AFD->getAsyncLoc())
-          .limitBehavior(behavior));
+                         AFD->diagnose(diag::not_objc_function_async, AFD)
+                             .highlight(AFD->getAsyncLoc())
+                             .limitBehavior(behavior));
       Reason.describe(AFD);
 
       return false;
@@ -817,7 +878,7 @@ bool swift::isRepresentableInObjC(
 
     // The completion handler transformation cannot properly represent a
     // dynamic 'Self' type, so disallow @objc for such methods.
-    if (FD->hasDynamicSelfResult()) {
+    if (FD->getResultInterfaceType()->hasDynamicSelfType()) {
       AFD->diagnose(diag::async_objc_dynamic_self)
           .highlight(AFD->getAsyncLoc())
           .limitBehavior(behavior);
@@ -844,15 +905,15 @@ bool swift::isRepresentableInObjC(
       completionHandlerParams.push_back(AnyFunctionType::Param(type));
 
       // Make sure that the parameter type is representable in Objective-C.
-      if (!type->isRepresentableIn(
-              ForeignLanguage::ObjectiveC, const_cast<FuncDecl *>(FD))) {
+      if (!type->isRepresentableIn(language, const_cast<FuncDecl *>(FD))) {
         softenIfAccessNote(AFD, Reason.getAttr(),
           AFD->diagnose(diag::objc_invalid_on_func_result_type,
-                        getObjCDiagnosticAttrKind(Reason))
+                        FD, getObjCDiagnosticAttrKind(Reason),
+                        language)
               .limitBehavior(behavior));
         diagnoseTypeNotRepresentableInObjC(FD, type,
                                            FD->getResultTypeSourceRange(),
-                                           behavior);
+                                           behavior, Reason);
         Reason.describe(FD);
 
         return true;
@@ -1141,9 +1202,8 @@ bool swift::isRepresentableInObjC(const VarDecl *VD, ObjCReason Reason) {
   // to mark them as @objc
   if (VD->getEffectfulGetAccessor()) {
     softenIfAccessNote(VD, Reason.getAttr(),
-      VD->diagnose(diag::effectful_not_representable_objc,
-                   VD->getDescriptiveKind())
-          .limitBehavior(behavior));
+                       VD->diagnose(diag::effectful_not_representable_objc, VD)
+                           .limitBehavior(behavior));
     Reason.describe(VD);
     return false;
   }
@@ -1160,7 +1220,7 @@ bool swift::isRepresentableInObjC(const VarDecl *VD, ObjCReason Reason) {
           .limitBehavior(behavior));
     diagnoseTypeNotRepresentableInObjC(VD->getDeclContext(),
                                        VD->getInterfaceType(),
-                                       TypeRange, behavior);
+                                       TypeRange, behavior, Reason);
     Reason.describe(VD);
   }
 
@@ -1188,19 +1248,18 @@ bool swift::isRepresentableInObjC(const SubscriptDecl *SD, ObjCReason Reason) {
   // to mark them as @objc
   if (SD->getEffectfulGetAccessor()) {
     softenIfAccessNote(SD, Reason.getAttr(),
-      SD->diagnose(diag::effectful_not_representable_objc,
-                   SD->getDescriptiveKind())
-          .limitBehavior(behavior));
+                       SD->diagnose(diag::effectful_not_representable_objc, SD)
+                           .limitBehavior(behavior));
     Reason.describe(SD);
     return false;
   }
 
   // ObjC doesn't support class subscripts.
   if (!SD->isInstanceMember()) {
-    softenIfAccessNote(SD, Reason.getAttr(),
-      SD->diagnose(diag::objc_invalid_on_static_subscript,
-                   SD->getDescriptiveKind(), Reason)
-          .limitBehavior(behavior));
+    softenIfAccessNote(
+        SD, Reason.getAttr(),
+        SD->diagnose(diag::objc_invalid_on_static_subscript, SD, Reason)
+            .limitBehavior(behavior));
     Reason.describe(SD);
     Reason.setAttrInvalid();
     return true;
@@ -1249,7 +1308,7 @@ bool swift::isRepresentableInObjC(const SubscriptDecl *SD, ObjCReason Reason) {
     diagnoseTypeNotRepresentableInObjC(SD->getDeclContext(),
                                        !IndexResult ? IndexType
                                                     : ElementType,
-                                       TypeRange, behavior);
+                                       TypeRange, behavior, Reason);
     Reason.describe(SD);
   }
 
@@ -1264,8 +1323,9 @@ bool swift::canBeRepresentedInObjC(const ValueDecl *decl) {
   if (auto func = dyn_cast<AbstractFunctionDecl>(decl)) {
     std::optional<ForeignAsyncConvention> asyncConvention;
     std::optional<ForeignErrorConvention> errorConvention;
-    return isRepresentableInObjC(func, ObjCReason::MemberOfObjCMembersClass,
-                                 asyncConvention, errorConvention);
+    return isRepresentableInLanguage(func,
+                                     ObjCReason::MemberOfObjCMembersClass,
+                                     asyncConvention, errorConvention);
   }
 
   if (auto var = dyn_cast<VarDecl>(decl))
@@ -1482,6 +1542,8 @@ shouldMarkAsObjC(const ValueDecl *VD, bool allowImplicit,
       case AccessorKind::WillSet:
       case AccessorKind::Init:
       case AccessorKind::DistributedGet:
+      case AccessorKind::Borrow:
+      case AccessorKind::Mutate:
         return false;
 
       case AccessorKind::MutableAddress:
@@ -1629,18 +1691,18 @@ static std::optional<ObjCReason> shouldMarkAsObjC(const ValueDecl *VD,
       .fixItInsert(VD->getAttributeInsertionLoc(suggestFinal),
                    suggestFinal ? "final " : "@nonobjc ");
 
-    VD->diagnose(diag::make_decl_objc, VD->getDescriptiveKind())
-      .fixItInsert(VD->getAttributeInsertionLoc(false), "@objc ");
+    VD->diagnose(diag::make_decl_objc, VD)
+        .fixItInsert(VD->getAttributeInsertionLoc(false), "@objc ");
   } else {
     ASSERT(currentlyObjC.has_value());
 
     VD->diagnose(diag::objc_implementation_will_become_nonobjc, VD)
       .fixItInsert(VD->getAttributeInsertionLoc(false), "@objc ");
 
-    VD->diagnose(diag::fixit_add_nonobjc_or_final_for_objc_implementation,
-                 VD->getDescriptiveKind(), suggestFinal)
-      .fixItInsert(VD->getAttributeInsertionLoc(suggestFinal),
-                   suggestFinal ? "final " : "@nonobjc ");
+    VD->diagnose(diag::fixit_add_nonobjc_or_final_for_objc_implementation, VD,
+                 suggestFinal)
+        .fixItInsert(VD->getAttributeInsertionLoc(suggestFinal),
+                     suggestFinal ? "final " : "@nonobjc ");
   }
 
   implAttr->setHasInvalidImplicitLangAttrs();
@@ -1653,8 +1715,7 @@ static void diagnoseInvalidObjCName(ValueDecl *VD, ObjCAttr *attr) {
   if (attr && !attr->getNameLocs().empty()) {
     // Locate the diagnostic on the name itself if it was explicitly provided.
     VD->getDiags().diagnose(attr->getNameLocs().front(),
-                            diag::objc_name_not_valid_identifier,
-                            VD->getDescriptiveKind());
+                            diag::objc_name_not_valid_identifier, VD);
   } else {
     switch (VD->getDescriptiveKind()) {
     case DescriptiveDeclKind::Getter:
@@ -1665,8 +1726,7 @@ static void diagnoseInvalidObjCName(ValueDecl *VD, ObjCAttr *attr) {
       // diagnostics for the getter/setter.
       break;
     default:
-      VD->diagnose(diag::objc_cannot_infer_name_raw_identifier,
-                   VD->getDescriptiveKind());
+      VD->diagnose(diag::objc_cannot_infer_name_raw_identifier, VD);
     }
   }
 }
@@ -1736,19 +1796,18 @@ static bool isCIntegerType(Type type) {
 }
 
 /// Determine whether the given enum should be @objc.
-static bool isEnumObjC(EnumDecl *enumDecl) {
+static bool isEnumObjC(EnumDecl *enumDecl, DeclAttribute *attr) {
   // FIXME: Use shouldMarkAsObjC once it loses it's TypeChecker argument.
 
-  // If there is no @objc attribute, it's not @objc.
-  auto attr = enumDecl->getAttrs().getAttribute<ObjCAttr>();
+  // If there is no @objc or @c attribute, skip it.
   if (!attr)
     return false;
 
   Type rawType = enumDecl->getRawType();
 
-  // @objc enums must have a raw type.
+  // @objc/@c enums must have a raw type.
   if (!rawType) {
-    enumDecl->diagnose(diag::objc_enum_no_raw_type);
+    enumDecl->diagnose(diag::objc_enum_no_raw_type, attr);
     return false;
   }
 
@@ -1761,7 +1820,7 @@ static bool isEnumObjC(EnumDecl *enumDecl) {
     SourceRange errorRange;
     if (!enumDecl->getInherited().empty())
       errorRange = enumDecl->getInherited().getEntry(0).getSourceRange();
-    enumDecl->diagnose(diag::objc_enum_raw_type_not_integer, rawType)
+    enumDecl->diagnose(diag::objc_enum_raw_type_not_integer, attr, rawType)
       .highlight(errorRange);
     return false;
   }
@@ -1771,7 +1830,8 @@ static bool isEnumObjC(EnumDecl *enumDecl) {
     enumDecl->diagnose(diag::empty_enum_raw_type);
   }
 
-  checkObjCNameValidity(enumDecl, attr);
+  if (auto objcAttr = dyn_cast<ObjCAttr>(attr))
+    checkObjCNameValidity(enumDecl, objcAttr);
   return true;
 }
 
@@ -1812,9 +1872,9 @@ bool IsObjCRequest::evaluate(Evaluator &evaluator, ValueDecl *VD) const {
   } else if (auto enumDecl = dyn_cast<EnumDecl>(VD)) {
     // Enums can be @objc so long as they have a raw type that is representable
     // as an arithmetic type in C.
-    if (isEnumObjC(enumDecl))
-      isObjC = objCReasonForObjCAttr(
-                                 enumDecl->getAttrs().getAttribute<ObjCAttr>());
+    auto attr = enumDecl->getAttrs().getAttribute<ObjCAttr>();
+    if (attr && isEnumObjC(enumDecl, attr))
+      isObjC = objCReasonForObjCAttr(attr);
   } else if (auto enumElement = dyn_cast<EnumElementDecl>(VD)) {
     // Enum elements can be @objc so long as the containing enum is @objc.
     if (enumElement->getParentEnum()->isObjC()) {
@@ -1839,9 +1899,7 @@ bool IsObjCRequest::evaluate(Evaluator &evaluator, ValueDecl *VD) const {
           proto->diagnose(diag::objc_protocol_inherits_non_objc_protocol,
                           proto->getDeclaredInterfaceType(),
                           inherited->getDeclaredInterfaceType());
-          inherited->diagnose(diag::kind_declname_declared_here,
-                              DescriptiveDeclKind::Protocol,
-                              inherited->getName());
+          inherited->diagnose(diag::decl_declared_here_with_kind, inherited);
           isObjC = std::nullopt;
         }
       }
@@ -1873,7 +1931,7 @@ bool IsObjCRequest::evaluate(Evaluator &evaluator, ValueDecl *VD) const {
   } else if (isa<DestructorDecl>(VD)) {
     // Destructors need no additional checking.
   } else if (auto func = dyn_cast<AbstractFunctionDecl>(VD)) {
-    if (!isRepresentableInObjC(
+    if (!isRepresentableInLanguage(
             func, *isObjC, asyncConvention, errorConvention)) {
       isObjC->setAttrInvalid();
       return false;
@@ -2244,8 +2302,7 @@ std::pair<unsigned, DeclName> swift::getObjCMethodDiagInfo(
   if (auto accessor = dyn_cast<AccessorDecl>(member)) {
     switch (accessor->getAccessorKind()) {
 #define OBJC_ACCESSOR(ID, KEYWORD)
-#define ACCESSOR(ID) \
-    case AccessorKind::ID:
+#define ACCESSOR(ID, KEYWORD) case AccessorKind::ID:
     case AccessorKind::DistributedGet:
 #include "swift/AST/AccessorKinds.def"
       llvm_unreachable("Not an Objective-C entry point");
@@ -3938,9 +3995,9 @@ class ObjCImplementationChecker {
     }
 
     case MatchOutcome::WrongStaticness: {
-      auto diag = diagnose(cand,
-                           diag::objc_implementation_class_or_instance_mismatch,
-                           cand, req->getDescriptiveKind());
+      auto diag =
+          diagnose(cand, diag::objc_implementation_class_or_instance_mismatch,
+                   cand, req);
       fixDeclarationStaticSpelling(diag, cand, getStaticSpelling(req));
       return;
     }
@@ -3953,8 +4010,7 @@ class ObjCImplementationChecker {
       return;
 
     case MatchOutcome::WrongDeclKind:
-      diagnose(cand, diag::objc_implementation_wrong_decl_kind,
-               cand, req->getDescriptiveKind());
+      diagnose(cand, diag::objc_implementation_wrong_decl_kind, cand, req);
       return;
 
     case MatchOutcome::WrongType:
@@ -3963,17 +4019,16 @@ class ObjCImplementationChecker {
       return;
 
     case MatchOutcome::WrongWritability:
-      diagnose(cand, diag::objc_implementation_must_be_settable,
-               cand, req->getDescriptiveKind());
+      diagnose(cand, diag::objc_implementation_must_be_settable, cand, req);
       return;
 
     case MatchOutcome::WrongRequiredAttr: {
       bool shouldBeRequired = cast<ConstructorDecl>(req)->isRequired();
 
       auto diag =
-        diagnose(cand, diag::objc_implementation_required_attr_mismatch,
-                 cand, req->getDescriptiveKind(),  shouldBeRequired);
-      
+          diagnose(cand, diag::objc_implementation_required_attr_mismatch, cand,
+                   req, shouldBeRequired);
+
       if (shouldBeRequired)
         diag.fixItInsert(cand->getAttributeInsertionLoc(/*forModifier=*/true),
                          "required ");
@@ -4048,18 +4103,46 @@ class ObjCImplementationChecker {
 
 public:
   void diagnoseUnmatchedRequirements() {
+    auto ext = dyn_cast<ExtensionDecl>(decl);
+    if (!ext)
+      return;
+
+    llvm::SmallString<128> stubs;
+    llvm::raw_svector_ostream stubStream(stubs);
+
+    unsigned numEmitted = 0;
+
     for (auto req : unmatchedRequirements) {
       // Ignore `@optional` protocol requirements.
       if (isOptionalObjCProtocolRequirement(req))
         continue;
 
-      auto ext = cast<IterableDeclContext>(req->getDeclContext()->getAsDecl())
-                        ->getImplementationContext();
+      if (numEmitted == 0) {
+        // Emit overall diagnostic for all the notes to attach to.
+        diagnose(ext, diag::objc_implementation_missing_impls,
+                 getCategoryName(req->getDeclContext()));
+      }
+
+      numEmitted += 1;
 
-      diagnose(ext->getDecl(), diag::objc_implementation_missing_impl,
-               getCategoryName(req->getDeclContext()), req);
+      // Emit different diagnostic if there's an async alternative.
+      if (auto asyncAlternative = getAsyncAlternative(req)) {
+        diagnose(ext, diag::objc_implementation_missing_impl_either,
+                 asyncAlternative, req);
+        req = asyncAlternative;
+      } else {
+        diagnose(ext, diag::objc_implementation_missing_impl, req);
+      }
+
+      // Append stub for this requirement into eventual fix-it.
+      swift::printRequirementStub(req, ext, ext->getSelfInterfaceType(),
+                                  ext->getStartLoc(), stubStream,
+                                  /*objCAttr=*/true);
+    }
 
-      // FIXME: Should give fix-it to add stub implementation
+    if (!stubs.empty()) {
+      diagnose(ext, diag::objc_implementation_missing_impls_fixit, numEmitted)
+        .fixItInsertAfter(ext->getBraces().Start, stubs);
     }
   }
 
@@ -4080,9 +4163,8 @@ class ObjCImplementationChecker {
                cand, cand->getDeclContext()->getSelfClassDecl());
 
       if (canBeRepresentedInObjC(cand)) {
-        auto diagnostic =
-            diagnose(cand, diag::fixit_add_private_for_objc_implementation,
-                     cand->getDescriptiveKind());
+        auto diagnostic = diagnose(
+            cand, diag::fixit_add_private_for_objc_implementation, cand);
         if (auto modifier = cand->getAttrs().getAttribute<AccessControlAttr>())
           diagnostic.fixItReplace(modifier->getRange(), "private");
         else
@@ -4093,7 +4175,7 @@ class ObjCImplementationChecker {
       // Initializers can't be 'final', but they can be '@nonobjc'
       bool suggestFinal = !isa<ConstructorDecl>(cand);
       diagnose(cand, diag::fixit_add_nonobjc_or_final_for_objc_implementation,
-               cand->getDescriptiveKind(), suggestFinal)
+               cand, suggestFinal)
           .fixItInsert(cand->getAttributeInsertionLoc(suggestFinal),
                        suggestFinal ? "final " : "@nonobjc ");
     }
@@ -4154,3 +4236,43 @@ evaluate(Evaluator &evaluator, Decl *D) const {
 
   return evaluator::SideEffect();
 }
+
+evaluator::SideEffect
+TypeCheckCDeclFunctionRequest::evaluate(Evaluator &evaluator,
+                                        FuncDecl *FD,
+                                        CDeclAttr *attr) const {
+  auto &ctx = FD->getASTContext();
+
+  auto lang = FD->getCDeclKind();
+  assert(lang && "missing @c?");
+  auto kind = lang == ForeignLanguage::ObjectiveC
+                      ? ObjCReason::ExplicitlyUnderscoreCDecl
+                      : ObjCReason::ExplicitlyCDecl;
+  ObjCReason reason(kind, attr);
+
+  std::optional<ForeignAsyncConvention> asyncConvention;
+  std::optional<ForeignErrorConvention> errorConvention;
+  if (isRepresentableInLanguage(FD, reason, asyncConvention, errorConvention)) {
+    if (FD->hasAsync()) {
+      FD->setForeignAsyncConvention(*asyncConvention);
+      ctx.Diags.diagnose(attr->getLocation(), diag::attr_decl_async,
+                         attr, FD);
+    } else if (FD->hasThrows()) {
+      FD->setForeignErrorConvention(*errorConvention);
+      ctx.Diags.diagnose(attr->getLocation(), diag::cdecl_throws,
+                         attr);
+    }
+  } else {
+    reason.setAttrInvalid();
+  }
+  return {};
+}
+
+evaluator::SideEffect
+TypeCheckCDeclEnumRequest::evaluate(Evaluator &evaluator,
+                                    EnumDecl *ED,
+                                    CDeclAttr *attr) const {
+  // Apply @objc's logic.
+  isEnumObjC(ED, attr);
+  return {};
+}
diff --git a/lib/Sema/TypeCheckDeclOverride.cpp b/lib/Sema/TypeCheckDeclOverride.cpp
index 85a113951a1e4..b733602c721f1 100644
--- a/lib/Sema/TypeCheckDeclOverride.cpp
+++ b/lib/Sema/TypeCheckDeclOverride.cpp
@@ -1,8 +1,8 @@
-//===--- TypeCheckOverride.cpp - Override Checking ------------------------===//
+//===-- Sema/TypeCheckDeclOverride.cpp - Override Checking ------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -22,7 +22,7 @@
 #include "TypeCheckUnsafe.h"
 #include "TypeChecker.h"
 #include "swift/AST/ASTVisitor.h"
-#include "swift/AST/AvailabilityInference.h"
+#include "swift/AST/AvailabilityConstraint.h"
 #include "swift/AST/AvailabilityRange.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/GenericEnvironment.h"
@@ -217,6 +217,9 @@ bool swift::isOverrideBasedOnType(const ValueDecl *decl, Type declTy,
         return false;
     }
 
+    if (declTy->is<ErrorType>())
+      return false;
+
     auto fnType1 = declTy->castTo<AnyFunctionType>();
     auto fnType2 = parentDeclTy->castTo<AnyFunctionType>();
     return AnyFunctionType::equalParams(fnType1->getParams(),
@@ -250,11 +253,11 @@ static bool isUnavailableInAllVersions(ValueDecl *decl) {
   auto constraints = getAvailabilityConstraintsForDecl(decl, deploymentContext);
   for (auto constraint : constraints) {
     switch (constraint.getReason()) {
-    case AvailabilityConstraint::Reason::UnconditionallyUnavailable:
-    case AvailabilityConstraint::Reason::UnavailableForDeployment:
+    case AvailabilityConstraint::Reason::UnavailableUnconditionally:
+    case AvailabilityConstraint::Reason::UnavailableUnintroduced:
       return true;
-    case AvailabilityConstraint::Reason::Obsoleted:
-    case AvailabilityConstraint::Reason::PotentiallyUnavailable:
+    case AvailabilityConstraint::Reason::UnavailableObsolete:
+    case AvailabilityConstraint::Reason::Unintroduced:
       break;
     }
   }
@@ -368,11 +371,9 @@ diagnoseMismatchedOptionals(const ValueDecl *member,
           return;
 
       emittedError = true;
-      auto diag = diags.diagnose(decl->getStartLoc(),
-                                 diag::override_optional_mismatch,
-                                 member->getDescriptiveKind(),
-                                 isa<SubscriptDecl>(member),
-                                 parentParamTy, paramTy);
+      auto diag = diags.diagnose(
+          decl->getStartLoc(), diag::override_optional_mismatch, member,
+          isa<SubscriptDecl>(member), parentParamTy, paramTy);
       if (repr->isSimple()) {
         diag.fixItInsertAfter(repr->getEndLoc(), "?");
       } else {
@@ -392,8 +393,8 @@ diagnoseMismatchedOptionals(const ValueDecl *member,
     }
 
     diags
-        .diagnose(decl->getStartLoc(), diag::override_unnecessary_IUO,
-                  member->getDescriptiveKind(), parentParamTy, paramTy)
+        .diagnose(decl->getStartLoc(), diag::override_unnecessary_IUO, member,
+                  parentParamTy, paramTy)
         .highlight(repr->getSourceRange());
 
     if (auto iuoRepr = dyn_cast<ImplicitlyUnwrappedOptionalTypeRepr>(repr)) {
@@ -435,11 +436,10 @@ diagnoseMismatchedOptionals(const ValueDecl *member,
       if (parentResultTy->getOptionalObjectType())
         return;
       emittedError = true;
-      auto diag = diags.diagnose(resultTL.getSourceRange().Start,
-                                 diag::override_optional_result_mismatch,
-                                 member->getDescriptiveKind(),
-                                 isa<SubscriptDecl>(member),
-                                 parentResultTy, resultTy);
+      auto diag =
+          diags.diagnose(resultTL.getSourceRange().Start,
+                         diag::override_optional_result_mismatch, member,
+                         isa<SubscriptDecl>(member), parentResultTy, resultTy);
       if (auto optForm = dyn_cast<OptionalTypeRepr>(TR)) {
         diag.fixItRemove(optForm->getQuestionLoc());
       } else if (auto iuoForm =
@@ -458,10 +458,11 @@ diagnoseMismatchedOptionals(const ValueDecl *member,
         return;
     }
 
-    diags.diagnose(resultTL.getSourceRange().Start,
-                   diag::override_unnecessary_result_IUO,
-                   member->getDescriptiveKind(), parentResultTy, resultTy)
-      .highlight(resultTL.getSourceRange());
+    diags
+        .diagnose(resultTL.getSourceRange().Start,
+                  diag::override_unnecessary_result_IUO, member, parentResultTy,
+                  resultTy)
+        .highlight(resultTL.getSourceRange());
 
     auto sugaredForm = dyn_cast<ImplicitlyUnwrappedOptionalTypeRepr>(TR);
     if (sugaredForm) {
@@ -525,7 +526,7 @@ static bool noteFixableMismatchedTypes(ValueDecl *decl, const ValueDecl *base) {
           if (!HasNotes)
             return std::nullopt;
           return diags.diagnose(decl, diag::override_type_mismatch_with_fixits,
-                                base->getDescriptiveKind(), baseTy);
+                                base, baseTy);
         });
   }
 
@@ -1115,8 +1116,7 @@ static void checkOverrideAccessControl(ValueDecl *baseDecl, ValueDecl *decl,
         .fixItReplace(cast<FuncDecl>(decl)->getFuncLoc(), getTokenText(tok::kw_var))
         .fixItReplace(cast<FuncDecl>(decl)->getParameters()->getSourceRange(), ": Int");
     } else {
-      diags.diagnose(decl, diag::override_of_non_open,
-                     decl->getDescriptiveKind());
+      diags.diagnose(decl, diag::override_of_non_open, decl);
     }
   } else if (baseHasOpenAccess &&
              classDecl->hasOpenAccess(dc) &&
@@ -1124,9 +1124,8 @@ static void checkOverrideAccessControl(ValueDecl *baseDecl, ValueDecl *decl,
              !decl->isSemanticallyFinal()) {
     {
       auto diag = diags.diagnose(decl, diag::override_not_accessible,
-                                 /*setter*/false,
-                                 decl->getDescriptiveKind(),
-                                 /*fromOverridden*/true);
+                                 /*setter*/ false, decl,
+                                 /*fromOverridden*/ true);
       fixItAccess(diag, decl, AccessLevel::Open);
     }
     diags.diagnose(baseDecl, diag::overridden_here);
@@ -1167,10 +1166,9 @@ static void checkOverrideAccessControl(ValueDecl *baseDecl, ValueDecl *decl,
       AccessLevel requiredAccess =
         requiredAccessScope->requiredAccessForDiagnostics();
       {
-        auto diag = diags.diagnose(decl, diag::override_not_accessible,
-                                   shouldDiagnoseSetter,
-                                   decl->getDescriptiveKind(),
-                                   overriddenForcesAccess);
+        auto diag =
+            diags.diagnose(decl, diag::override_not_accessible,
+                           shouldDiagnoseSetter, decl, overriddenForcesAccess);
         fixItAccess(diag, decl, requiredAccess, shouldDiagnoseSetter);
       }
       diags.diagnose(baseDecl, diag::overridden_here);
@@ -1537,7 +1535,8 @@ bool swift::checkOverrides(ValueDecl *decl) {
 
   auto &ctx = decl->getASTContext();
   if (overridden.empty() &&
-      ctx.LangOpts.hasFeature(Feature::MemberImportVisibility)) {
+      ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                              /*allowMigration=*/true)) {
     // If we didn't find anything, try broadening the search by ignoring missing
     // imports.
     if (!checkPotentialOverrides(decl, overridden,
@@ -1590,16 +1589,17 @@ namespace  {
     UNINTERESTING_ATTR(AccessControl)
     UNINTERESTING_ATTR(Alignment)
     UNINTERESTING_ATTR(AlwaysEmitIntoClient)
+    UNINTERESTING_ATTR(NeverEmitIntoClient)
     UNINTERESTING_ATTR(Borrowed)
     UNINTERESTING_ATTR(Borrowing)
     UNINTERESTING_ATTR(CDecl)
+    UNINTERESTING_ATTR(Concurrent)
     UNINTERESTING_ATTR(Consuming)
     UNINTERESTING_ATTR(Documentation)
     UNINTERESTING_ATTR(Dynamic)
     UNINTERESTING_ATTR(DynamicCallable)
     UNINTERESTING_ATTR(DynamicMemberLookup)
     UNINTERESTING_ATTR(SILGenName)
-    UNINTERESTING_ATTR(Execution)
     UNINTERESTING_ATTR(Exported)
     UNINTERESTING_ATTR(ForbidSerializingReference)
     UNINTERESTING_ATTR(GKInspectable)
@@ -1615,11 +1615,13 @@ namespace  {
     UNINTERESTING_ATTR(Isolated)
     UNINTERESTING_ATTR(Optimize)
     UNINTERESTING_ATTR(Exclusivity)
+    UNINTERESTING_ATTR(Nonexhaustive)
     UNINTERESTING_ATTR(NoLocks)
     UNINTERESTING_ATTR(NoAllocation)
     UNINTERESTING_ATTR(NoRuntime)
     UNINTERESTING_ATTR(NoExistentials)
     UNINTERESTING_ATTR(NoObjCBridging)
+    UNINTERESTING_ATTR(ManualOwnership)
     UNINTERESTING_ATTR(Inlinable)
     UNINTERESTING_ATTR(Effects)
     UNINTERESTING_ATTR(Expose)
@@ -1660,6 +1662,7 @@ namespace  {
     UNINTERESTING_ATTR(SwiftNativeObjCRuntimeBase)
     UNINTERESTING_ATTR(ShowInInterface)
     UNINTERESTING_ATTR(Specialize)
+    UNINTERESTING_ATTR(Specialized)
     UNINTERESTING_ATTR(SpecializeExtension)
     UNINTERESTING_ATTR(DynamicReplacement)
     UNINTERESTING_ATTR(PrivateImport)
@@ -1751,6 +1754,7 @@ namespace  {
     UNINTERESTING_ATTR(Unsafe)
     UNINTERESTING_ATTR(Safe)
     UNINTERESTING_ATTR(AddressableForDependencies)
+    UNINTERESTING_ATTR(UnsafeSelfDependentResult)
 #undef UNINTERESTING_ATTR
 
     void visitABIAttr(ABIAttr *attr) {
@@ -1809,160 +1813,97 @@ OverrideRequiresKeyword swift::overrideRequiresKeyword(ValueDecl *overridden) {
   return OverrideRequiresKeyword::Always;
 }
 
-/// Returns true if the availability of the overriding declaration
-/// makes it a safe override, given the availability of the base declaration.
-static bool isAvailabilitySafeForOverride(ValueDecl *override,
-                                          ValueDecl *base) {
-  // API availability ranges are contravariant: make sure the version range
-  // of an overridden declaration is fully contained in the range of the
-  // overriding declaration.
-  AvailabilityRange overrideInfo =
-      AvailabilityInference::availableRange(override);
-  AvailabilityRange baseInfo = AvailabilityInference::availableRange(base);
-
-  if (baseInfo.isContainedIn(overrideInfo))
-    return true;
+enum class OverrideAvailability {
+  /// The unavailability of the base decl and override decl are compatible.
+  Compatible,
+  /// The base decl is unavailable but the override decl is not.
+  BaseUnavailable,
+  /// The override decl is unavailable but the base decl is not.
+  OverrideUnavailable,
+  /// The override decl is less available than the base decl.
+  OverrideLessAvailable,
+  /// Do not diagnose the unavailability of these decls.
+  Ignored,
+};
 
-  // Allow overrides that are not as available as the base decl as long as the
-  // override is as available as its context.
-  auto availabilityContext = AvailabilityContext::forDeclSignature(
-      override->getDeclContext()->getSelfNominalTypeDecl());
+static std::pair<OverrideAvailability, std::optional<AvailabilityConstraint>>
+getOverrideAvailability(ValueDecl *override, ValueDecl *base) {
+  auto &ctx = override->getASTContext();
 
-  return availabilityContext.getPlatformRange().isContainedIn(overrideInfo);
-}
+  // Availability is contravariant so make sure the availability of of an
+  // overridden declaration is fully contained in the availability of the
+  // overriding declaration.
+  auto baseAvailability = AvailabilityContext::forDeclSignature(base);
 
-/// Returns true if a diagnostic about an accessor being less available
-/// than the accessor it overrides would be redundant because we will
-/// already emit another diagnostic.
-static bool
-isRedundantAccessorOverrideAvailabilityDiagnostic(ValueDecl *override,
-                                                  ValueDecl *base) {
+  // The override is allowed to be less available than the base decl as long as
+  // it is as available as its containing nominal decl.
+  auto nominalAvailability = AvailabilityContext::forDeclSignature(
+      override->getDeclContext()->getSelfNominalTypeDecl());
+  baseAvailability.constrainWithContext(nominalAvailability, ctx);
 
-  auto *overrideFn = dyn_cast<AccessorDecl>(override);
-  auto *baseFn = dyn_cast<AccessorDecl>(base);
-  if (!overrideFn || !baseFn)
-    return false;
+  // In order to maintain source compatibility, universally unavailable decls
+  // are allowed to override universally unavailable bases.
+  AvailabilityConstraintFlags flags;
+  flags |= AvailabilityConstraintFlag::
+      AllowUniversallyUnavailableInCompatibleContexts;
 
-  AbstractStorageDecl *overrideASD = overrideFn->getStorage();
-  AbstractStorageDecl *baseASD = baseFn->getStorage();
-  if (overrideASD->getOverriddenDecl() != baseASD)
-    return false;
+  if (auto constraint =
+          getAvailabilityConstraintsForDecl(override, baseAvailability, flags)
+              .getPrimaryConstraint()) {
+    if (constraint->isUnavailable())
+      return {OverrideAvailability::OverrideUnavailable, constraint};
 
-  // If we have already emitted a diagnostic about an unsafe override
-  // for the property, don't complain about the accessor.
-  if (!isAvailabilitySafeForOverride(overrideASD, baseASD)) {
-    return true;
+    return {OverrideAvailability::OverrideLessAvailable, constraint};
   }
 
-  // Returns true if we will already diagnose a bad override
-  // on the property's accessor of the given kind.
-  auto accessorOverrideAlreadyDiagnosed = [&](AccessorKind kind) {
-    FuncDecl *overrideAccessor = overrideASD->getOpaqueAccessor(kind);
-    FuncDecl *baseAccessor = baseASD->getOpaqueAccessor(kind);
-    if (overrideAccessor && baseAccessor &&
-        !isAvailabilitySafeForOverride(overrideAccessor, baseAccessor)) {
-      return true;
-    }
-    return false;
-  };
-
-  // If we have already emitted a diagnostic about an unsafe override
-  // for a getter or a setter, no need to complain about the read or
-  // modify coroutines, which are synthesized to be as available as either
-  // the getter and the setter.
-  switch (overrideFn->getAccessorKind()) {
-  case AccessorKind::Get:
-  case AccessorKind::DistributedGet:
-  case AccessorKind::Set:
-    break;
-
-  case AccessorKind::Read:
-  case AccessorKind::Read2:
-    if (accessorOverrideAlreadyDiagnosed(AccessorKind::Get))
-      return true;
-    break;
-
-  case AccessorKind::Modify:
-  case AccessorKind::Modify2:
-    if (accessorOverrideAlreadyDiagnosed(AccessorKind::Get) ||
-        accessorOverrideAlreadyDiagnosed(AccessorKind::Set)) {
-      return true;
-    }
-    break;
-
-#define OPAQUE_ACCESSOR(ID, KEYWORD)
-#define ACCESSOR(ID) \
-  case AccessorKind::ID:
-#include "swift/AST/AccessorKinds.def"
-    llvm_unreachable("checking override for non-opaque accessor");
+  // Check whether the base is unavailable from the perspective of the override.
+  auto overrideAvailability = AvailabilityContext::forDeclSignature(override);
+  if (auto baseConstraint =
+          getAvailabilityConstraintsForDecl(base, overrideAvailability, flags)
+              .getPrimaryConstraint()) {
+    if (baseConstraint->isUnavailable())
+      return {OverrideAvailability::BaseUnavailable, baseConstraint};
   }
 
-  return false;
+  return {OverrideAvailability::Compatible, std::nullopt};
 }
 
-/// Diagnose an override for potential availability. Returns true if
-/// a diagnostic was emitted and false otherwise.
-static bool diagnoseOverrideForAvailability(ValueDecl *override,
-                                            ValueDecl *base) {
-  if (isAvailabilitySafeForOverride(override, base))
-    return false;
-
-  // Suppress diagnostics about availability overrides for accessors
-  // if they would be redundant with other diagnostics.
-  if (isRedundantAccessorOverrideAvailabilityDiagnostic(override, base))
-    return false;
-
-  auto &diags = override->getASTContext().Diags;
-  diags.diagnose(override, diag::override_less_available, override);
-  diags.diagnose(base, diag::overridden_here);
-
-  return true;
-}
-
-enum class OverrideUnavailabilityStatus {
-  /// The unavailability of the base decl and override decl are compatible.
-  Compatible,
-  /// The base decl is unavailable but the override decl is not.
-  BaseUnavailable,
-  /// Do not diagnose the unavailability of these decls.
-  Ignored,
-};
-
-static std::pair<OverrideUnavailabilityStatus,
-                 std::optional<SemanticAvailableAttr>>
-checkOverrideUnavailability(ValueDecl *override, ValueDecl *base) {
-  if (auto *overrideParent = override->getDeclContext()->getAsDecl()) {
-    // If the parent of the override is unavailable, then the unavailability of
-    // the override decl is irrelevant.
-    if (AvailabilityContext::forDeclSignature(overrideParent).isUnavailable())
-      return {OverrideUnavailabilityStatus::Ignored, std::nullopt};
+static std::pair<OverrideAvailability, std::optional<AvailabilityConstraint>>
+checkOverrideAvailability(ValueDecl *override, ValueDecl *base) {
+  auto &ctx = override->getASTContext();
+  if (ctx.LangOpts.DisableAvailabilityChecking)
+    return {OverrideAvailability::Ignored, std::nullopt};
+
+  auto result = getOverrideAvailability(override, base);
+  switch (result.first) {
+  case OverrideAvailability::Ignored:
+  case OverrideAvailability::Compatible:
+    return result;
+  case OverrideAvailability::BaseUnavailable:
+  case OverrideAvailability::OverrideUnavailable:
+  case OverrideAvailability::OverrideLessAvailable:
+    break;
   }
 
-  if (auto *baseAccessor = dyn_cast<AccessorDecl>(base)) {
-    // Ignore implicit accessors since the diagnostics are likely to duplicate
-    // the diagnostics for the explicit accessors that availability was inferred
-    // from.
+  auto *overrideAccessor = dyn_cast<AccessorDecl>(override);
+  auto *baseAccessor = dyn_cast<AccessorDecl>(base);
+  if (baseAccessor && overrideAccessor) {
+    // Skip implicit accessors since they're synthesized with availability that
+    // matches the accessors that they were derived from and therefore
+    // diagnostics for them will be redundant.
     if (baseAccessor->isImplicit())
-      return {OverrideUnavailabilityStatus::Ignored, std::nullopt};
+      return {OverrideAvailability::Ignored, std::nullopt};
 
-    if (auto *overrideAccessor = dyn_cast<AccessorDecl>(override)) {
-      // If base and override are accessors, check whether the unavailability of
-      // their storage matches. Diagnosing accessors with invalid storage
-      // produces redundant diagnostics.
-      if (checkOverrideUnavailability(overrideAccessor->getStorage(),
-                                      baseAccessor->getStorage())
-              .first != OverrideUnavailabilityStatus::Compatible)
-        return {OverrideUnavailabilityStatus::Ignored, std::nullopt};
-    }
+    // If we're checking an accessor that's overriding another accessor, ignore
+    // the result if we get the same result for the underlying storage
+    // (otherwise we'll emit redundant diagnostics).
+    if (checkOverrideAvailability(overrideAccessor->getStorage(),
+                                  baseAccessor->getStorage())
+            .first != OverrideAvailability::Compatible)
+      return {OverrideAvailability::Ignored, std::nullopt};
   }
 
-  auto baseUnavailableAttr = base->getUnavailableAttr();
-  auto overrideUnavailableAttr = override->getUnavailableAttr();
-
-  if (baseUnavailableAttr && !overrideUnavailableAttr)
-    return {OverrideUnavailabilityStatus::BaseUnavailable, baseUnavailableAttr};
-
-  return {OverrideUnavailabilityStatus::Compatible, std::nullopt};
+  return result;
 }
 
 static bool checkSingleOverride(ValueDecl *override, ValueDecl *base) {
@@ -2043,12 +1984,12 @@ static bool checkSingleOverride(ValueDecl *override, ValueDecl *base) {
     // Make sure an effectful storage decl is only overridden by a storage
     // decl with the same or fewer effect kinds.
     if (!overrideASD->isLessEffectfulThan(baseASD, EffectKind::Async)) {
-      diags.diagnose(overrideASD, diag::override_with_more_effects,
-                     overrideASD->getDescriptiveKind(), "async");
+      diags.diagnose(overrideASD, diag::override_with_more_effects, overrideASD,
+                     "async");
       return true;
     } else if (!overrideASD->isLessEffectfulThan(baseASD, EffectKind::Throws)) {
-      diags.diagnose(overrideASD, diag::override_with_more_effects,
-                     overrideASD->getDescriptiveKind(), "throwing");
+      diags.diagnose(overrideASD, diag::override_with_more_effects, overrideASD,
+                     "throwing");
       return true;
     }
   }
@@ -2154,15 +2095,14 @@ static bool checkSingleOverride(ValueDecl *override, ValueDecl *base) {
     switch (compareThrownErrorsForSubtyping(
                 overrideThrownError, baseThrownError, overrideFn)) {
     case ThrownErrorSubtyping::DropsThrows:
-      diags.diagnose(override, diag::override_with_more_effects,
-                     override->getDescriptiveKind(), "throwing");
+      diags.diagnose(override, diag::override_with_more_effects, override,
+                     "throwing");
       diags.diagnose(base, diag::overridden_here);
       break;
 
     case ThrownErrorSubtyping::Mismatch:
-      diags.diagnose(override, diag::override_typed_throws,
-                     override->getDescriptiveKind(), overrideThrownError,
-                     baseThrownError);
+      diags.diagnose(override, diag::override_typed_throws, overrideFn,
+                     overrideThrownError, baseThrownError);
       diags.diagnose(base, diag::overridden_here);
       break;
 
@@ -2181,8 +2121,8 @@ static bool checkSingleOverride(ValueDecl *override, ValueDecl *base) {
     // problem.
     if (overrideFn->hasAsync() &&
         !cast<AbstractFunctionDecl>(base)->hasAsync()) {
-      diags.diagnose(override, diag::override_with_more_effects,
-                     override->getDescriptiveKind(), "async");
+      diags.diagnose(override, diag::override_with_more_effects, override,
+                     "async");
       diags.diagnose(base, diag::overridden_here);
     }
 
@@ -2219,11 +2159,10 @@ static bool checkSingleOverride(ValueDecl *override, ValueDecl *base) {
       case DescriptiveDeclKind::StaticProperty:
       case DescriptiveDeclKind::StaticMethod:
       case DescriptiveDeclKind::StaticSubscript:
-        override->diagnose(diag::override_static, baseKind);
+        override->diagnose(diag::override_static, base);
         break;
       default:
-        override->diagnose(diag::override_final,
-                           override->getDescriptiveKind(), baseKind);
+        override->diagnose(diag::override_final, override, base);
         break;
       }
     }
@@ -2233,14 +2172,11 @@ static bool checkSingleOverride(ValueDecl *override, ValueDecl *base) {
     return true;
   }
 
-  // FIXME: [availability] Possibly should extend to more availability checking.
-  auto unavailabilityStatusAndAttr =
-      checkOverrideUnavailability(override, base);
-  auto unavailableAttr = unavailabilityStatusAndAttr.second;
-
-  switch (unavailabilityStatusAndAttr.first) {
-  case OverrideUnavailabilityStatus::BaseUnavailable: {
-    diagnoseOverrideOfUnavailableDecl(override, base, unavailableAttr.value());
+  auto [status, constraint] = checkOverrideAvailability(override, base);
+  switch (status) {
+  case OverrideAvailability::BaseUnavailable: {
+    auto unavailableAttr = constraint->getAttr();
+    diagnoseOverrideOfUnavailableDecl(override, base, unavailableAttr);
 
     if (isUnavailableInAllVersions(base)) {
       auto modifier = override->getAttrs().getAttribute<OverrideAttr>();
@@ -2253,16 +2189,42 @@ static bool checkSingleOverride(ValueDecl *override, ValueDecl *base) {
     }
     break;
   }
-  case OverrideUnavailabilityStatus::Compatible:
-  case OverrideUnavailabilityStatus::Ignored:
+  case OverrideAvailability::OverrideUnavailable: {
+    auto unavailableAttr = constraint->getAttr();
+    auto domain = unavailableAttr.getDomain();
+    auto parsedAttr = unavailableAttr.getParsedAttr();
+
+    switch (domain.getKind()) {
+    case AvailabilityDomain::Kind::Universal:
+    case AvailabilityDomain::Kind::SwiftLanguageMode:
+    case AvailabilityDomain::Kind::SwiftRuntime:
+    case AvailabilityDomain::Kind::PackageDescription:
+    case AvailabilityDomain::Kind::Platform:
+      // FIXME: [availability] Diagnose as an error in a future Swift version.
+      break;
+    case AvailabilityDomain::Kind::Embedded:
+    case AvailabilityDomain::Kind::Custom:
+      if (parsedAttr->getLocation().isValid())
+        ctx.Diags.diagnose(override, diag::override_unavailable, override)
+            .fixItRemove(parsedAttr->getRangeWithAt());
+      else
+        ctx.Diags.diagnose(override, diag::override_unavailable, override);
+      ctx.Diags.diagnose(base, diag::overridden_here);
+      break;
+    }
+    break;
+  }
+  case OverrideAvailability::OverrideLessAvailable: {
+    ctx.Diags.diagnose(override, diag::override_less_available, override);
+    ctx.Diags.diagnose(base, diag::overridden_here);
     break;
   }
-
-  if (!ctx.LangOpts.DisableAvailabilityChecking) {
-    diagnoseOverrideForAvailability(override, base);
+  case OverrideAvailability::Compatible:
+  case OverrideAvailability::Ignored:
+    break;
   }
 
-  if (ctx.LangOpts.hasFeature(Feature::StrictMemorySafety)) {
+  if (ctx.LangOpts.hasFeature(Feature::StrictMemorySafety, /*allowMigration=*/true)) {
     // If the override is unsafe but the base declaration is not, then the
     // inheritance itself is unsafe.
     auto subs = SubstitutionMap::getOverrideSubstitutions(base, override);
@@ -2409,6 +2371,8 @@ computeOverriddenDecls(ValueDecl *decl, bool ignoreMissingImports) {
     case AccessorKind::Read2:
     case AccessorKind::Modify:
     case AccessorKind::Modify2:
+    case AccessorKind::Borrow:
+    case AccessorKind::Mutate:
       break;
 
     case AccessorKind::WillSet:
@@ -2459,8 +2423,7 @@ computeOverriddenDecls(ValueDecl *decl, bool ignoreMissingImports) {
         break;
 
 #define OPAQUE_ACCESSOR(ID, KEYWORD)
-#define ACCESSOR(ID) \
-      case AccessorKind::ID:
+#define ACCESSOR(ID, KEYWORD) case AccessorKind::ID:
 #include "swift/AST/AccessorKinds.def"
         llvm_unreachable("non-opaque accessor was required as opaque by base");
       }
@@ -2533,7 +2496,8 @@ OverriddenDeclsRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
   // If we didn't find anything, try broadening the search by ignoring missing
   // imports.
   if (overridden.empty() &&
-      ctx.LangOpts.hasFeature(Feature::MemberImportVisibility)) {
+      ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                              /*allowMigration=*/true)) {
     overridden = computeOverriddenDecls(decl, true);
     if (!overridden.empty()) {
       auto first = overridden.front();
@@ -2591,7 +2555,7 @@ void swift::checkImplementationOnlyOverride(const ValueDecl *VD) {
   ModuleDecl *M = overridden->getModuleContext();
   if (SF->getRestrictedImportKind(M) == RestrictedImportKind::ImplementationOnly) {
     VD->diagnose(diag::implementation_only_override_import_without_attr,
-                 overridden->getDescriptiveKind())
+                 overridden)
         .fixItInsert(VD->getAttributeInsertionLoc(false),
                      "@_implementationOnly ");
     overridden->diagnose(diag::overridden_here);
@@ -2599,8 +2563,7 @@ void swift::checkImplementationOnlyOverride(const ValueDecl *VD) {
   }
 
   if (overridden->getAttrs().hasAttribute<ImplementationOnlyAttr>()) {
-    VD->diagnose(diag::implementation_only_override_without_attr,
-                 overridden->getDescriptiveKind())
+    VD->diagnose(diag::implementation_only_override_without_attr, overridden)
         .fixItInsert(VD->getAttributeInsertionLoc(false),
                      "@_implementationOnly ");
     overridden->diagnose(diag::overridden_here);
diff --git a/lib/Sema/TypeCheckDeclPrimary.cpp b/lib/Sema/TypeCheckDeclPrimary.cpp
index 09655a05d246f..9f62de5e5bce8 100644
--- a/lib/Sema/TypeCheckDeclPrimary.cpp
+++ b/lib/Sema/TypeCheckDeclPrimary.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -17,12 +17,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
-#include "DerivedConformances.h"
+#include "DerivedConformance/DerivedConformance.h"
 #include "MiscDiagnostics.h"
 #include "TypeCheckAccess.h"
 #include "TypeCheckAvailability.h"
 #include "TypeCheckConcurrency.h"
 #include "TypeCheckDecl.h"
+#include "TypeCheckEmbedded.h"
 #include "TypeCheckMacros.h"
 #include "TypeCheckObjC.h"
 #include "TypeCheckType.h"
@@ -78,21 +79,6 @@ using namespace swift;
 
 #define DEBUG_TYPE "TypeCheckDeclPrimary"
 
-static Type containsParameterizedProtocolType(Type inheritedTy) {
-  if (inheritedTy->is<ParameterizedProtocolType>()) {
-    return inheritedTy;
-  }
-
-  if (auto *compositionTy = inheritedTy->getAs<ProtocolCompositionType>()) {
-    for (auto memberTy : compositionTy->getMembers()) {
-      if (auto paramTy = containsParameterizedProtocolType(memberTy))
-        return paramTy;
-    }
-  }
-
-  return Type();
-}
-
 class CheckRepressions {
   llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *> declUnion;
   ASTContext &ctx;
@@ -200,7 +186,7 @@ static void checkInheritanceClause(
       }
     }
   } else {
-    typeDecl = declUnion.get<const TypeDecl *>();
+    typeDecl = cast<const TypeDecl *>(declUnion);
     decl = typeDecl;
   }
 
@@ -303,14 +289,6 @@ static void checkInheritanceClause(
       inheritedAnyObject = { i, inherited.getSourceRange() };
     }
 
-    if (auto paramTy = containsParameterizedProtocolType(inheritedTy)) {
-      if (!isa<ProtocolDecl>(decl)) {
-        decl->diagnose(diag::inheritance_from_parameterized_protocol,
-                       paramTy);
-      }
-      continue;
-    }
-
     if (inheritedTy->isConstraintType()) {
       auto layout = inheritedTy->getExistentialLayout();
 
@@ -588,12 +566,16 @@ static void checkGenericParams(GenericContext *ownerCtx) {
       hasPack = true;
     }
 
-    if (gp->isValue()) {
-      // Value generic nominal types require runtime support.
-      //
-      // Embedded doesn't require runtime support for this feature.
-      if (isa<NominalTypeDecl>(decl) &&
-          !ctx.LangOpts.hasFeature(Feature::Embedded)) {
+    // Value generic nominal types require runtime support.
+    if (gp->isValue() && isa<NominalTypeDecl>(decl)) {
+      auto nomTypeDecl = cast<NominalTypeDecl>(decl);
+      // But: Embedded doesn't require runtime support for this feature.
+      // But: Stdlib/libswiftCore carries its own support,
+      //      so non-public stdlib declarations are safe
+      if (!ctx.LangOpts.hasFeature(Feature::Embedded) &&
+          !(decl->getModuleContext()->isStdlibModule() &&
+            !nomTypeDecl->isAccessibleFrom(nullptr))) {
+        // Everything else gets diagnosed for availability
         TypeChecker::checkAvailability(
           gp->getSourceRange(),
           ctx.getValueGenericTypeAvailability(),
@@ -618,15 +600,15 @@ static void checkGenericParams(GenericContext *ownerCtx) {
 /// Returns \c true if \p current and \p other are in the same source file
 /// \em and \c current appears before \p other in that file.
 static bool isBeforeInSameFile(Decl *current, Decl *other) {
-  if (current->getDeclContext()->getParentSourceFile() !=
-                  other->getDeclContext()->getParentSourceFile())
+  if (current->getDeclContext()->getOutermostParentSourceFile() !=
+                  other->getDeclContext()->getOutermostParentSourceFile())
     return false;
 
-  if (!current->getLoc().isValid())
+  if (current->getLoc().isInvalid() || other->getLoc().isInvalid())
     return false;
 
   return current->getASTContext().SourceMgr
-                        .isBeforeInBuffer(current->getLoc(), other->getLoc());
+                        .isBefore(current->getLoc(), other->getLoc());
 }
 
 template <typename T>
@@ -728,6 +710,20 @@ CheckRedeclarationRequest::evaluate(Evaluator &eval, ValueDecl *current,
       auto found = nominal->lookupDirect(current->getBaseName(), SourceLoc(),
                                          flags);
       otherDefinitions.append(found.begin(), found.end());
+
+      // Look into the generics of the type. Value generic parameters can appear
+      // as static members of the type.
+      if (auto genericDC = static_cast<Decl *>(nominal)->getAsGenericContext()) {
+        auto gpList = genericDC->getGenericParams();
+
+        if (gpList && !current->getBaseName().isSpecial()) {
+          auto gp = gpList->lookUpGenericParam(current->getBaseIdentifier());
+
+          if (gp && gp->isValue()) {
+            otherDefinitions.push_back(gp);
+          }
+        }
+      }
     }
   } else if (currentDC->isLocalContext()) {
     if (!current->isImplicit()) {
@@ -1081,8 +1077,7 @@ CheckRedeclarationRequest::evaluate(Evaluator &eval, ValueDecl *current,
                     return req->getName() == VD->getName();
                   });
             }
-            declToDiagnose->diagnose(diag::invalid_redecl_implicit,
-                                     current->getDescriptiveKind(),
+            declToDiagnose->diagnose(diag::invalid_redecl_implicit, current,
                                      isProtocolRequirement, other);
 
             // Emit a specialized note if the one of the declarations is
@@ -1136,6 +1131,7 @@ CheckRedeclarationRequest::evaluate(Evaluator &eval, ValueDecl *current,
       break;
     }
   }
+
   return std::make_tuple<>();
 }
 
@@ -1201,73 +1197,18 @@ static bool checkExpressionMacroDefaultValueRestrictions(ParamDecl *param) {
 #endif
 }
 
-void TypeChecker::notePlaceholderReplacementTypes(Type writtenType,
-                                                  Type inferredType) {
-  assert(writtenType && inferredType &&
-         "Must provide both written and inferred types");
-  assert(writtenType->hasPlaceholder() && "Written type has no placeholder?");
-
-  class PlaceholderNotator
-      : public CanTypeDifferenceVisitor<PlaceholderNotator> {
-  public:
-    bool visitDifferentComponentTypes(CanType t1, CanType t2) {
-      // Never replace anything the user wrote with an error type.
-      if (t2->hasError() || t2->hasUnresolvedType()) {
-        return false;
-      }
-
-      auto *placeholder = t1->getAs<PlaceholderType>();
-      if (!placeholder) {
-        return false;
-      }
-
-      if (auto *origRepr =
-              placeholder->getOriginator().dyn_cast<TypeRepr *>()) {
-        assert(isa<PlaceholderTypeRepr>(origRepr));
-        t1->getASTContext()
-            .Diags
-            .diagnose(origRepr->getLoc(),
-                      diag::replace_placeholder_with_inferred_type, t2)
-            .fixItReplace(origRepr->getSourceRange(), t2.getString());
-      }
-      return false;
-    }
-
-    bool check(Type t1, Type t2) {
-      return !visit(t1->getCanonicalType(), t2->getCanonicalType());
-    };
-  };
-
-  PlaceholderNotator().check(writtenType, inferredType);
-}
-
 /// Check the default arguments that occur within this parameter list.
 static void checkDefaultArguments(ParameterList *params) {
   // Force the default values in case they produce diagnostics.
   for (auto *param : *params) {
-    auto ifacety = param->getInterfaceType();
-    auto *expr = param->getTypeCheckedDefaultExpr();
+    (void)param->getTypeCheckedDefaultExpr();
 
     // Force captures since this can emit diagnostics.
-    (void) param->getDefaultArgumentCaptureInfo();
+    (void)param->getDefaultArgumentCaptureInfo();
 
     // If the default argument has isolation, it must match the
     // isolation of the decl context.
     (void)param->getInitializerIsolation();
-
-    if (!ifacety->hasPlaceholder()) {
-      continue;
-    }
-
-    // Placeholder types are banned for all parameter decls. We try to use the
-    // freshly-checked default expression's contextual type to suggest a
-    // reasonable type to insert.
-    param->diagnose(diag::placeholder_type_not_allowed_in_parameter)
-        .highlight(param->getSourceRange());
-    if (expr && !expr->getType()->hasError()) {
-      TypeChecker::notePlaceholderReplacementTypes(
-          ifacety, expr->getType()->mapTypeOutOfContext());
-    }
   }
 }
 
@@ -1786,6 +1727,33 @@ static TypeRepr *unwrapAttributedRepr(TypeRepr *repr) {
   return repr;
 }
 
+static void collectProtocolsFromInheritedEntry(
+    const InheritedEntry &entry,
+    Type inheritedTy,
+    llvm::SmallPtrSetImpl<ProtocolDecl *> &protocolsWithRetroactiveAttr,
+    SmallVectorImpl<ProtocolDecl *> &protos) {
+
+  if (auto *protoTy = inheritedTy->getAs<ProtocolType>()) {
+    auto *proto = protoTy->getDecl();
+
+    // As a fallback, to support previous language versions, also allow
+    // this through if the protocol has been explicitly module-qualified.
+    TypeRepr *repr = unwrapAttributedRepr(entry.getTypeRepr());
+    if (isModuleQualified(repr, proto->getParentModule())) {
+      protocolsWithRetroactiveAttr.insert(proto);
+    }
+
+    protos.push_back(proto);
+  } else if (auto *pct = inheritedTy->getAs<ProtocolCompositionType>()) {
+    for (auto member : pct->getMembers()) {
+      collectProtocolsFromInheritedEntry(entry, member,
+                                         protocolsWithRetroactiveAttr, protos);
+    }
+  } else if (auto *ppt = inheritedTy->getAs<ParameterizedProtocolType>()) {
+    protos.push_back(ppt->getProtocol());
+  }
+}
+
 /// Determines if this extension declares a conformance of a type declared
 /// outside this module to a protocol declared outside this module (but only
 /// in library evolution mode)
@@ -1809,106 +1777,101 @@ static void diagnoseRetroactiveConformances(
     return;
   }
 
-  Type extendedType = ext->getExtendedType();
   NominalTypeDecl *extendedNominalDecl = ext->getExtendedNominal();
-  if (!extendedNominalDecl) {
+  if (!extendedNominalDecl || isa<BuiltinTupleDecl>(extendedNominalDecl))
     return;
-  }
 
   ModuleDecl *extTypeModule = extendedNominalDecl->getParentModule();
 
   // If the type comes from the __ObjC clang header module, don't warn.
-  if (extTypeModule->getName().is(CLANG_HEADER_MODULE_NAME)) {
+  if (extTypeModule->getName().is(CLANG_HEADER_MODULE_NAME))
     return;
-  }
 
   // At this point, we know we're extending a type declared outside this module.
   // We better only be conforming it to protocols declared within this module.
-  llvm::SmallSetVector<ProtocolDecl *, 8> externalProtocols;
-  llvm::SmallSet<ProtocolDecl *, 8> protocolsWithRetroactiveAttr;
-  for (const InheritedEntry &entry : ext->getInherited().getEntries()) {
-    if (entry.getType().isNull() || !entry.getTypeRepr()) {
-      continue;
+  llvm::SmallMapVector<ProtocolDecl *, bool, 8> protocols;
+  llvm::SmallPtrSet<ProtocolDecl *, 2> protocolsWithRetroactiveAttr;
+
+  for (auto *conformance : ext->getLocalConformances()) {
+    auto *proto = conformance->getProtocol();
+    bool inserted = protocols.insert(std::make_pair(
+        proto, conformance->isRetroactive())).second;
+    ASSERT(inserted);
+
+    if (proto->isSpecificProtocol(KnownProtocolKind::SendableMetatype)) {
+      protocolsWithRetroactiveAttr.insert(proto);
     }
 
-    auto proto =
-        dyn_cast_or_null<ProtocolDecl>(entry.getType()->getAnyNominal());
-    if (!proto) {  
-      continue;
+    // Implied conformance to Sendable is a special case that should not be
+    // diagnosed. Pretend it's always @retroactive.
+    if (conformance->getSourceKind() == ConformanceEntryKind::Implied &&
+        proto->isSpecificProtocol(KnownProtocolKind::Sendable) &&
+        extendedNominalDecl->hasClangNode()) {
+      protocolsWithRetroactiveAttr.insert(proto);
     }
-    
-    // As a fallback, to support previous language versions, also allow
-    // this through if the protocol has been explicitly module-qualified.
-    TypeRepr *repr = unwrapAttributedRepr(entry.getTypeRepr());
-    if (isModuleQualified(repr, proto->getParentModule())) {
+  }
+
+  for (const InheritedEntry &entry : ext->getInherited().getEntries()) {
+    auto inheritedTy = entry.getType();
+    if (inheritedTy.isNull() || !entry.getTypeRepr()) {
       continue;
     }
 
-    proto->walkInheritedProtocols([&](ProtocolDecl *decl) {
-
-      // Get the original conformance of the extended type to this protocol.
-      auto conformanceRef = lookupConformance(extendedType, decl);
-      if (!conformanceRef.isConcrete()) {
-        return TypeWalker::Action::Continue;
-      }
-      auto conformance = conformanceRef.getConcrete();
-
-      // If that conformance came from this extension, then we warn. Otherwise
-      // we will have diagnosed it on the extension that actually declares this
-      // specific conformance.
-      if (conformance->getDeclContext() != ext) {
-        return TypeWalker::Action::Continue;
-      }
+    SmallVector<ProtocolDecl *, 2> protos;
+    collectProtocolsFromInheritedEntry(entry, inheritedTy,
+                                       protocolsWithRetroactiveAttr, protos);
+
+    for (auto *proto : protos) {
+      proto->walkInheritedProtocols([&](ProtocolDecl *decl) {
+        // If this isn't a retroactive conformance, skip it.
+        auto found = protocols.find(proto);
+        if (found != protocols.end() && !found->second) {
+          // However, if this is the protocol in the inherited type entry,
+          // check to make sure it's not erroneously marked @retroactive when it's
+          // not actually retroactive.
+          if (decl == proto && entry.isRetroactive()) {
+            auto loc =
+                entry.getTypeRepr()->findAttrLoc(TypeAttrKind::Retroactive);
+
+            bool typeInSamePackage = extTypeModule->inSamePackage(module);
+            bool typeIsSameModule =
+                extTypeModule->isSameModuleLookingThroughOverlays(module);
+
+            auto declForDiag = (typeIsSameModule || typeInSamePackage)
+                                   ? extendedNominalDecl
+                                   : proto;
+            bool isSameModule = declForDiag->getParentModule()
+                                    ->isSameModuleLookingThroughOverlays(module);
+
+            diags
+                .diagnose(loc, diag::retroactive_attr_does_not_apply, declForDiag,
+                          isSameModule)
+                .warnUntilSwiftVersion(6)
+                .fixItRemove(SourceRange(loc, loc.getAdvancedLoc(1)));
+            return TypeWalker::Action::Stop;
+          }
+          return TypeWalker::Action::Continue;
+        }
 
-      // If this isn't a retroactive conformance, skip it.
-      if (!conformance->isRetroactive()) {
-        // However, if this is the protocol in the inherited type entry,
-        // check to make sure it's not erroneously marked @retroactive when it's
-        // not actually retroactive.
-        if (decl == proto && entry.isRetroactive()) {
-          auto loc =
-              entry.getTypeRepr()->findAttrLoc(TypeAttrKind::Retroactive);
-
-          bool typeInSamePackage = extTypeModule->inSamePackage(module);
-          bool typeIsSameModule =
-              extTypeModule->isSameModuleLookingThroughOverlays(module);
-
-          auto declForDiag = (typeIsSameModule || typeInSamePackage)
-                                 ? extendedNominalDecl
-                                 : proto;
-          bool isSameModule = declForDiag->getParentModule()
-                                  ->isSameModuleLookingThroughOverlays(module);
-
-          diags
-              .diagnose(loc, diag::retroactive_attr_does_not_apply, declForDiag,
-                        isSameModule)
-              .warnUntilSwiftVersion(6)
-              .fixItRemove(SourceRange(loc, loc.getAdvancedLoc(1)));
-          return TypeWalker::Action::Stop;
+        // If it's marked @retroactive, no need to warn.
+        if (entry.isRetroactive()) {
+          // Note that we encountered this protocol through a conformance marked
+          // @retroactive in case multiple clauses cause the protocol to be
+          // inherited.
+          protocolsWithRetroactiveAttr.insert(decl);
+          return TypeWalker::Action::Continue;
         }
-        return TypeWalker::Action::Continue;
-      }
 
-      // If it's marked @retroactive, no need to warn.
-      if (entry.isRetroactive()) {
-        // Note that we encountered this protocol through a conformance marked
-        // @retroactive in case multiple clauses cause the protocol to be
-        // inherited.
-        protocolsWithRetroactiveAttr.insert(decl);
         return TypeWalker::Action::Continue;
-      }
-
-      // If we've come this far, we know this extension is the first declaration
-      // of the conformance of the extended type to this protocol.
-      externalProtocols.insert(decl);
-
-      return TypeWalker::Action::Continue;
-    });
+      });
+    }
   }
 
   // Remove protocols that are reachable through a @retroactive conformance.
-  for (auto *proto : protocolsWithRetroactiveAttr) {
-    externalProtocols.remove(proto);
+  SmallSetVector<ProtocolDecl *, 4> externalProtocols;
+  for (auto pair : protocols) {
+    if (pair.second && !protocolsWithRetroactiveAttr.count(pair.first))
+      externalProtocols.insert(pair.first);
   }
 
   // If we didn't find any violations, we're done.
@@ -1990,199 +1953,6 @@ void TypeChecker::diagnoseDuplicateCaptureVars(CaptureListExpr *expr) {
   diagnoseDuplicateDecls(captureListVars);
 }
 
-static StringRef prettyPrintAttrs(const ValueDecl *VD,
-                                  ArrayRef<const DeclAttribute *> attrs,
-                                  SmallVectorImpl<char> &out) {
-  llvm::raw_svector_ostream os(out);
-  StreamPrinter printer(os);
-
-  PrintOptions opts = PrintOptions::printDeclarations();
-  VD->getAttrs().print(printer, opts, attrs, VD);
-  return StringRef(out.begin(), out.size()).drop_back();
-}
-
-static void diagnoseChangesByAccessNote(
-    ValueDecl *VD,
-    ArrayRef<const DeclAttribute *> attrs,
-    Diag<StringRef, StringRef, DescriptiveDeclKind> diagID,
-    Diag<StringRef> fixItID,
-    llvm::function_ref<void(InFlightDiagnostic, StringRef)> addFixIts) {
-  if (!VD->getASTContext().LangOpts.shouldRemarkOnAccessNoteSuccess() ||
-      attrs.empty())
-    return;
-
-  // Generate string containing all attributes.
-  SmallString<64> attrString;
-  auto attrText = prettyPrintAttrs(VD, attrs, attrString);
-
-  SourceLoc fixItLoc;
-
-  auto reason = VD->getModuleContext()->getAccessNotes().Reason;
-  auto diag = VD->diagnose(diagID, reason, attrText, VD->getDescriptiveKind());
-  for (auto attr : attrs) {
-    diag.highlight(attr->getRangeWithAt());
-    if (fixItLoc.isInvalid())
-      fixItLoc = attr->getRangeWithAt().Start;
-  }
-  diag.flush();
-
-  if (!fixItLoc)
-    fixItLoc = VD->getAttributeInsertionLoc(true);
-
-  addFixIts(VD->getASTContext().Diags.diagnose(fixItLoc, fixItID, attrText),
-            attrString);
-}
-
-template <typename Attr>
-static void addOrRemoveAttr(ValueDecl *VD, const AccessNotesFile &notes,
-                            std::optional<bool> expected,
-                            SmallVectorImpl<DeclAttribute *> &removedAttrs,
-                            llvm::function_ref<Attr *()> willCreate) {
-  if (!expected) return;
-
-  auto attr = VD->getAttrs().getAttribute<Attr>();
-  if (*expected == (attr != nullptr)) return;
-
-  if (*expected) {
-    attr = willCreate();
-    attr->setAddedByAccessNote();
-    VD->getAttrs().add(attr);
-
-    // Arrange for us to emit a remark about this attribute after type checking
-    // has ensured it's valid.
-    if (auto SF = VD->getDeclContext()->getParentSourceFile())
-      SF->AttrsAddedByAccessNotes[VD].push_back(attr);
-  } else {
-    removedAttrs.push_back(attr);
-    VD->getAttrs().removeAttribute(attr);
-  }
-}
-
-InFlightDiagnostic
-swift::softenIfAccessNote(const Decl *D, const DeclAttribute *attr,
-                          InFlightDiagnostic &diag) {
-  const ValueDecl *VD = dyn_cast<ValueDecl>(D);
-  if (!VD || !attr || !attr->getAddedByAccessNote())
-    return std::move(diag);
-
-  SmallString<32> attrString;
-  auto attrText = prettyPrintAttrs(VD, llvm::ArrayRef(attr), attrString);
-
-  ASTContext &ctx = D->getASTContext();
-  auto behavior = ctx.LangOpts.getAccessNoteFailureLimit();
-  return std::move(diag.wrapIn(diag::wrap_invalid_attr_added_by_access_note,
-                               D->getModuleContext()->getAccessNotes().Reason,
-                               ctx.AllocateCopy(attrText), D->getDescriptiveKind())
-                        .limitBehavior(behavior));
-}
-
-static void applyAccessNote(ValueDecl *VD, const AccessNote &note,
-                            const AccessNotesFile &notes) {
-  ASTContext &ctx = VD->getASTContext();
-  SmallVector<DeclAttribute *, 2> removedAttrs;
-
-  addOrRemoveAttr<ObjCAttr>(VD, notes, note.ObjC, removedAttrs, [&]{
-    return ObjCAttr::create(ctx, note.ObjCName, false);
-  });
-
-  addOrRemoveAttr<DynamicAttr>(VD, notes, note.Dynamic, removedAttrs, [&]{
-    return new (ctx) DynamicAttr(true);
-  });
-
-  // FIXME: If we ever have more attributes, we'll need to sort removedAttrs by
-  // SourceLoc. As it is, attrs are always before modifiers, so we're okay now.
-
-  diagnoseChangesByAccessNote(VD, removedAttrs,
-                              diag::attr_removed_by_access_note,
-                              diag::fixit_attr_removed_by_access_note,
-                              [&](InFlightDiagnostic diag, StringRef code) {
-    for (auto attr : llvm::reverse(removedAttrs))
-      diag.fixItRemove(attr->getRangeWithAt());
-  });
-
-  if (note.ObjCName) {
-    auto newName = note.ObjCName.value();
-
-    // addOrRemoveAttr above guarantees there's an ObjCAttr on this decl.
-    auto attr = VD->getAttrs().getAttribute<ObjCAttr>();
-    assert(attr && "ObjCName set, but ObjCAttr not true or did not apply???");
-
-    if (!attr->hasName()) {
-      // There was already an @objc attribute with no selector. Set it.
-      attr->setName(newName, true);
-
-      if (!ctx.LangOpts.shouldRemarkOnAccessNoteSuccess())
-        return;
-
-      VD->diagnose(diag::attr_objc_name_changed_by_access_note,
-                   notes.Reason, VD->getDescriptiveKind(), newName);
-
-      auto fixIt =
-          VD->diagnose(diag::fixit_attr_objc_name_changed_by_access_note);
-      fixDeclarationObjCName(fixIt, VD, ObjCSelector(), newName);
-    }
-    else if (attr->getName() != newName) {
-      // There was already an @objc
-      auto behavior = ctx.LangOpts.getAccessNoteFailureLimit();
-
-      VD->diagnose(diag::attr_objc_name_conflicts_with_access_note,
-                   notes.Reason, VD->getDescriptiveKind(),
-                   attr->getName().value(), newName)
-          .highlight(attr->getRangeWithAt())
-          .limitBehavior(behavior);
-    }
-  }
-}
-
-void TypeChecker::applyAccessNote(ValueDecl *VD) {
-  (void)evaluateOrDefault(VD->getASTContext().evaluator,
-                          ApplyAccessNoteRequest{VD}, {});
-}
-
-void swift::diagnoseAttrsAddedByAccessNote(SourceFile &SF) {
-  if (!SF.getASTContext().LangOpts.shouldRemarkOnAccessNoteSuccess())
-    return;
-
-  for (auto declAndAttrs : SF.AttrsAddedByAccessNotes) {
-    auto D = declAndAttrs.getFirst();
-    SmallVector<DeclAttribute *, 4> sortedAttrs;
-    llvm::append_range(sortedAttrs, declAndAttrs.getSecond());
-
-    // Filter out invalid attributes.
-    sortedAttrs.erase(
-      llvm::remove_if(sortedAttrs, [](DeclAttribute *attr) {
-        assert(attr->getAddedByAccessNote());
-        return attr->isInvalid();
-      }), sortedAttrs.end());
-    if (sortedAttrs.empty()) continue;
-
-    // Sort attributes by name.
-    llvm::sort(sortedAttrs, [](DeclAttribute * first, DeclAttribute * second) {
-      return first->getAttrName() < second->getAttrName();
-    });
-    sortedAttrs.erase(std::unique(sortedAttrs.begin(), sortedAttrs.end()),
-                      sortedAttrs.end());
-
-    diagnoseChangesByAccessNote(D, sortedAttrs, diag::attr_added_by_access_note,
-                                diag::fixit_attr_added_by_access_note,
-                                [=](InFlightDiagnostic diag, StringRef code) {
-      diag.fixItInsert(D->getAttributeInsertionLoc(/*isModifier=*/true), code);
-    });
-  }
-}
-
-evaluator::SideEffect
-ApplyAccessNoteRequest::evaluate(Evaluator &evaluator, ValueDecl *VD) const {
-  // Access notes don't apply to ABI-only attributes.
-  if (!ABIRoleInfo(VD).providesAPI())
-    return {};
-
-  AccessNotesFile &notes = VD->getModuleContext()->getAccessNotes();
-  if (auto note = notes.lookup(VD))
-    applyAccessNote(VD, *note.get(), notes);
-  return {};
-}
-
 static void diagnoseWrittenPlaceholderTypes(ASTContext &Ctx,
                                             const Pattern *P,
                                             Expr *init) {
@@ -2289,7 +2059,7 @@ static void dumpGenericSignature(ASTContext &ctx, GenericContext *GC) {
         GC->printContext(llvm::errs());
       }
       llvm::errs() << "Generic signature: ";
-      PrintOptions Opts;
+      PrintOptions Opts = PrintOptions::forDebugging();
       Opts.ProtocolQualifiedDependentMemberTypes = true;
       Opts.PrintInverseRequirements =
           !ctx.TypeCheckerOpts.DebugInverseRequirements;
@@ -2401,7 +2171,8 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
         // If strict memory safety checking is enabled, check the storage
         // of the nominal type.
-        if (Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety) &&
+        if (Ctx.LangOpts.hasFeature(
+                Feature::StrictMemorySafety, /*allowMigration=*/true) &&
             !isa<ProtocolDecl>(nominal)) {
           checkUnsafeStorage(nominal);
         }
@@ -2474,11 +2245,16 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     // concurrency checking enabled.
     if (ID->preconcurrency() &&
         Ctx.LangOpts.StrictConcurrencyLevel == StrictConcurrency::Complete &&
-        Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety)) {
+        Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety) &&
+        ID->getExplicitSafety() != ExplicitSafety::Unsafe) {
       diagnoseUnsafeUse(UnsafeUse::forPreconcurrencyImport(ID));
     }
   }
 
+  void visitUsingDecl(UsingDecl *UD) {
+    // Nothing to validate yet.
+  }
+
   void visitOperatorDecl(OperatorDecl *OD) {
     TypeChecker::checkDeclAttributes(OD);
     checkRedeclaration(OD);
@@ -3210,11 +2986,13 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
     // Temporary restriction until we figure out pattern matching and
     // enum case construction with packs.
-    if (auto genericSig = ED->getGenericSignature()) {
-      for (auto paramTy : genericSig.getGenericParams()) {
-        if (paramTy->isParameterPack()) {
-          ED->diagnose(diag::enum_with_pack);
-          break;
+    if (!ED->isSynthesized()) {
+      if (auto genericSig = ED->getGenericSignature()) {
+        for (auto paramTy : genericSig.getGenericParams()) {
+          if (paramTy->isParameterPack()) {
+            ED->diagnose(diag::enum_with_pack);
+            break;
+          }
         }
       }
     }
@@ -3236,8 +3014,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     diagnoseMissingExplicitSendable(ED);
     checkAccessControl(ED);
 
-    TypeChecker::checkPatternBindingCaptures(ED);
-
     auto &DE = Ctx.Diags;
     if (auto rawTy = ED->getRawType()) {
       // The raw type must be one of the blessed literal convertible types.
@@ -3255,6 +3031,13 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       }
     }
 
+    // If the enum is exported to C, it must be representable in C.
+    if (auto CDeclAttr = ED->getAttrs().getAttribute<swift::CDeclAttr>()) {
+      evaluateOrDefault(Ctx.evaluator,
+                        TypeCheckCDeclEnumRequest{ED, CDeclAttr},
+                        {});
+    }
+
     // -----
     // NonCopyableChecks
     //
@@ -3307,8 +3090,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       visit(Member);
     }
 
-    TypeChecker::checkPatternBindingCaptures(SD);
-
     checkInheritanceClause(SD);
     diagnoseMissingExplicitSendable(SD);
 
@@ -3490,8 +3271,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     for (Decl *Member : CD->getABIMembers())
       visit(Member);
 
-    TypeChecker::checkPatternBindingCaptures(CD);
-
     // If this class requires all of its stored properties to have
     // in-class initializers, diagnose this now.
     if (CD->requiresStoredPropertyInits())
@@ -3652,7 +3431,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       PD->dumpRef(llvm::errs());
       llvm::errs() << "\n";
       llvm::errs() << "Requirement signature: ";
-      PrintOptions Opts;
+      PrintOptions Opts = PrintOptions::forDebugging();
       Opts.ProtocolQualifiedDependentMemberTypes = true;
       Opts.PrintInverseRequirements =
           !Ctx.TypeCheckerOpts.DebugInverseRequirements;
@@ -3699,13 +3478,14 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
         TypeChecker::checkProtocolSelfRequirements(FD);
       }
 
-      checkAccessControl(FD);
-
       TypeChecker::checkParameterList(FD->getParameters(), FD);
     }
 
+    checkAccessControl(FD);
+
     TypeChecker::checkDeclAttributes(FD);
     TypeChecker::checkDistributedFunc(FD);
+    checkEmbeddedRestrictionsInSignature(FD);
 
     if (!checkOverrides(FD)) {
       // If a method has an 'override' keyword but does not
@@ -3790,24 +3570,10 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     }
 
     // If the function is exported to C, it must be representable in (Obj-)C.
-    // FIXME: This needs to be moved to its own request if we want to
-    // productize @_cdecl.
     if (auto CDeclAttr = FD->getAttrs().getAttribute<swift::CDeclAttr>()) {
-      std::optional<ForeignAsyncConvention> asyncConvention;
-      std::optional<ForeignErrorConvention> errorConvention;
-      ObjCReason reason(ObjCReason::ExplicitlyCDecl, CDeclAttr);
-      if (isRepresentableInObjC(FD, reason, asyncConvention, errorConvention)) {
-        if (FD->hasAsync()) {
-          FD->setForeignAsyncConvention(*asyncConvention);
-          Ctx.Diags.diagnose(CDeclAttr->getLocation(), diag::attr_decl_async,
-                             CDeclAttr, FD);
-        } else if (FD->hasThrows()) {
-          FD->setForeignErrorConvention(*errorConvention);
-          Ctx.Diags.diagnose(CDeclAttr->getLocation(), diag::cdecl_throws);
-        }
-      } else {
-        reason.setAttrInvalid();
-      }
+      evaluateOrDefault(Ctx.evaluator,
+                        TypeCheckCDeclFunctionRequest{FD, CDeclAttr},
+                        {});
     }
 
     TypeChecker::checkObjCImplementation(FD);
@@ -3890,10 +3656,8 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       return;
 
     auto &ctx = ED->getASTContext();
-
-    if (!ctx.LangOpts.hasFeature(Feature::TupleConformances)) {
-      ED->diagnose(diag::experimental_tuple_extension);
-    }
+    ASSERT(ctx.LangOpts.hasFeature(Feature::TupleConformances) &&
+           "Extension binding should not have permitted this");
 
     if (!isValidExtendedTypeForTupleExtension(ED)) {
       ED->diagnose(diag::tuple_extension_wrong_type,
@@ -3997,11 +3761,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       return;
     }
 
-    // Record a dependency from TypeCheckPrimaryFileRequest to
-    // ExtendedNominalRequest, since the call to getExtendedNominal()
-    // above doesn't record a dependency when reading a cached value.
-    ED->computeExtendedNominal();
-
     if (!extType->hasError()) {
       // The first condition catches syntactic forms like
       //     protocol A & B { ... } // may be protocols or typealiases
@@ -4022,7 +3781,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
                                  nominal->getDeclaredType());
         diag.highlight(extTypeRepr->getSourceRange());
         if (firstNominalIsNotMostSpecific) {
-          diag.flush();
           Type mostSpecificProtocol = extTypeNominal->getDeclaredType();
           ED->diagnose(diag::composition_in_extended_type_alternative,
                        mostSpecificProtocol)
@@ -4074,8 +3832,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     for (Decl *Member : ED->getMembers())
       visit(Member);
 
-    TypeChecker::checkPatternBindingCaptures(ED);
-
     TypeChecker::checkConformancesInContext(ED);
 
     checkAccessControl(ED);
@@ -4113,6 +3869,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
     TypeChecker::checkDeclAttributes(CD);
     TypeChecker::checkParameterList(CD->getParameters(), CD);
+    checkEmbeddedRestrictionsInSignature(CD);
 
     if (CD->getAsyncLoc().isValid())
       TypeChecker::checkConcurrencyAvailability(CD->getAsyncLoc(), CD);
diff --git a/lib/Sema/TypeCheckDistributed.cpp b/lib/Sema/TypeCheckDistributed.cpp
index 146e5ad3ade62..669810eefc328 100644
--- a/lib/Sema/TypeCheckDistributed.cpp
+++ b/lib/Sema/TypeCheckDistributed.cpp
@@ -565,8 +565,7 @@ bool CheckDistributedFunctionRequest::evaluate(
         if (checkConformance(paramTy, req).isInvalid()) {
           auto diag = func->diagnose(
               diag::distributed_actor_func_param_not_codable,
-              param->getArgumentName().str(), param->getInterfaceType(),
-              func->getDescriptiveKind(),
+              param->getArgumentName(), param->getInterfaceType(), func,
               serializationRequirementIsCodable ? "Codable"
                                                 : req->getNameStr());
 
@@ -710,6 +709,11 @@ void TypeChecker::checkDistributedActor(SourceFile *SF, NominalTypeDecl *nominal
   if (!swift::ensureDistributedModuleLoaded(nominal))
     return;
 
+  auto &C = nominal->getASTContext();
+  auto loc = nominal->getLoc();
+  recordRequiredImportAccessLevelForDecl(C.getDistributedActorDecl(), nominal,
+                                         nominal->getEffectiveAccess(), loc);
+
   // ==== Constructors
   // --- Get the default initializer
   // If applicable, this will create the default 'init(transport:)' initializer
diff --git a/lib/Sema/TypeCheckEffects.cpp b/lib/Sema/TypeCheckEffects.cpp
index 9a23b3b8a66ec..1cf491b90686f 100644
--- a/lib/Sema/TypeCheckEffects.cpp
+++ b/lib/Sema/TypeCheckEffects.cpp
@@ -335,6 +335,7 @@ class AbstractFunction {
   PolymorphicEffectKind RethrowsKind = PolymorphicEffectKind::None;
   PolymorphicEffectKind ReasyncKind = PolymorphicEffectKind::None;
   SubstitutionMap Substitutions;
+  SelfApplyExpr *AppliedSelf = nullptr;
 
 public:
   explicit AbstractFunction(Kind kind, Expr *fn)
@@ -342,11 +343,13 @@ class AbstractFunction {
     TheExpr = fn;
   }
 
-  explicit AbstractFunction(AbstractFunctionDecl *fn, SubstitutionMap subs)
+  explicit AbstractFunction(AbstractFunctionDecl *fn, SubstitutionMap subs,
+                            SelfApplyExpr *appliedSelf)
     : TheKind(Kind::Function),
       RethrowsKind(fn->getPolymorphicEffectKind(EffectKind::Throws)),
       ReasyncKind(fn->getPolymorphicEffectKind(EffectKind::Async)),
-      Substitutions(subs) {
+      Substitutions(subs),
+      AppliedSelf(appliedSelf) {
     TheFunction = fn;
   }
 
@@ -367,22 +370,35 @@ class AbstractFunction {
     switch (kind) {
     case EffectKind::Throws: return RethrowsKind;
     case EffectKind::Async: return ReasyncKind;
-    case EffectKind::Unsafe: return swift::PolymorphicEffectKind::None;
+    case EffectKind::Unsafe:
+      switch (getExplicitSafety()) {
+      case ExplicitSafety::Safe:
+        return PolymorphicEffectKind::None;
+      case ExplicitSafety::Unsafe:
+        return PolymorphicEffectKind::Always;
+      case ExplicitSafety::Unspecified:
+        return PolymorphicEffectKind::ByClosure;
+      }
     }
     llvm_unreachable("Bad effect kind");
   }
 
   Type getType() const {
     switch (getKind()) {
-    case Kind::Opaque: return getOpaqueFunction()->getType();
+    case Kind::Opaque:
+      return getOpaqueFunction()->getType()->lookThroughAllOptionalTypes();
     case Kind::Function: {
       auto *AFD = getFunction();
-      if (AFD->hasImplicitSelfDecl())
+      if (AFD->hasImplicitSelfDecl() && AppliedSelf)
         return AFD->getMethodInterfaceType();
       return AFD->getInterfaceType();
     }
     case Kind::Closure: return getClosure()->getType();
-    case Kind::Parameter: return getParameter()->getInterfaceType();
+    case Kind::Parameter:
+      auto *param = getParameter();
+      auto *dc = param->getDeclContext();
+      return dc->mapTypeIntoContext(param->getInterfaceType())
+          ->lookThroughAllOptionalTypes();
     }
     llvm_unreachable("bad kind");
   }
@@ -398,6 +414,11 @@ class AbstractFunction {
                  .getParameterType();
 
     case Kind::Function: {
+      if (getFunction()->hasImplicitSelfDecl() && !AppliedSelf) {
+        assert(substIndex == 0);
+        return getFunction()->getImplicitSelfDecl()->getInterfaceType();
+      }
+
       auto *params = getFunction()->getParameters();
       auto origIndex = params->getOrigParamIndex(getSubstitutions(), substIndex);
       return params->get(origIndex)->getInterfaceType();
@@ -405,6 +426,22 @@ class AbstractFunction {
     }
   }
 
+  Type getOrigParamSelfType() const {
+    switch (getKind()) {
+    case Kind::Opaque:
+    case Kind::Closure:
+    case Kind::Parameter:
+      return Type();
+
+    case Kind::Function:
+      if (getFunction()->hasImplicitSelfDecl() && AppliedSelf) {
+        return getFunction()->getImplicitSelfDecl()->getInterfaceType();
+      }
+
+      return Type();
+    }
+  }
+
   bool isAutoClosure() const {
     if (getKind() == Kind::Closure)
       return isa<AutoClosureExpr>(getClosure());
@@ -428,17 +465,37 @@ class AbstractFunction {
     return TheExpr;
   }
 
+  SelfApplyExpr *getAppliedSelf() const {
+    return AppliedSelf;
+  }
+
   SubstitutionMap getSubstitutions() const {
     return Substitutions;
   }
 
-  static AbstractFunction getAppliedFn(ApplyExpr *apply) {
+  ExplicitSafety getExplicitSafety() const {
+    switch (getKind()) {
+    case Kind::Closure:
+    case Kind::Opaque:
+    case Kind::Parameter:
+      return ExplicitSafety::Unspecified;
+
+    case Kind::Function:
+      return getFunction()->getExplicitSafety();
+    }
+  }
+
+  static AbstractFunction getAppliedFn(ApplyExpr *apply,
+                                       Expr **calleeFn = nullptr) {
     Expr *fn = apply->getFn()->getValueProvidingExpr();
 
-    if (auto *selfCall = dyn_cast<SelfApplyExpr>(fn))
+    SelfApplyExpr *appliedSelf = nullptr;
+    if (auto *selfCall = dyn_cast<SelfApplyExpr>(fn)) {
+      appliedSelf = selfCall;
       fn = selfCall->getFn()->getValueProvidingExpr();
+    }
 
-    return decomposeFunction(fn);
+    return decomposeFunction(fn, appliedSelf, calleeFn);
   }
 
   bool isPreconcurrency() const {
@@ -457,7 +514,9 @@ class AbstractFunction {
     }
   }
 
-  static AbstractFunction decomposeFunction(Expr *fn) {
+  static AbstractFunction decomposeFunction(Expr *fn,
+                                            SelfApplyExpr *appliedSelf,
+                                            Expr **calleeFn) {
     assert(fn->getValueProvidingExpr() == fn);
 
     while (true) {
@@ -489,18 +548,24 @@ class AbstractFunction {
         break;
       }
     }
-    
+
+    // Tell our caller about the callee, if they asked for it.
+    if (calleeFn)
+      *calleeFn = fn;
+
     // Constructor delegation.
     if (auto otherCtorDeclRef = dyn_cast<OtherConstructorDeclRefExpr>(fn)) {
       return AbstractFunction(otherCtorDeclRef->getDecl(),
-                              otherCtorDeclRef->getDeclRef().getSubstitutions());
+                              otherCtorDeclRef->getDeclRef().getSubstitutions(),
+                              appliedSelf);
     }
 
     // Normal function references.
     if (auto DRE = dyn_cast<DeclRefExpr>(fn)) {
       ValueDecl *decl = DRE->getDecl();
       if (auto fn = dyn_cast<AbstractFunctionDecl>(decl)) {
-        return AbstractFunction(fn, DRE->getDeclRef().getSubstitutions());
+        return AbstractFunction(fn, DRE->getDeclRef().getSubstitutions(),
+                                appliedSelf);
       } else if (auto param = dyn_cast<ParamDecl>(decl)) {
         SubstitutionMap subs;
         if (auto genericEnv = param->getDeclContext()->getGenericEnvironmentOfContext())
@@ -603,10 +668,12 @@ class EffectsHandlingWalker : public ASTWalker {
                                       /*isImplicitlyAsync=*/false,
                                       /*isImplicitlyThrows=*/false);
     } else if (auto *LE = dyn_cast<LiteralExpr>(E)) {
-      recurse = asImpl().checkDeclRef(LE, LE->getInitializer(), LE->getLoc(),
-                                      /*isEvaluated=*/false,
-                                      /*isImplicitlyAsync=*/false,
-                                      /*isImplicitlyThrows=*/false);
+      if (LE->getInitializer()) {
+        recurse = asImpl().checkDeclRef(LE, LE->getInitializer(), LE->getLoc(),
+                                        /*isEvaluated=*/false,
+                                        /*isImplicitlyAsync=*/false,
+                                        /*isImplicitlyThrows=*/false);
+      }
     } else if (auto *CE = dyn_cast<CollectionExpr>(E)) {
       recurse = asImpl().checkDeclRef(CE, CE->getInitializer(), CE->getLoc(),
                                       /*isEvaluated=*/false,
@@ -648,6 +715,8 @@ class EffectsHandlingWalker : public ASTWalker {
       }
     } else if (auto TE = dyn_cast<MakeTemporarilyEscapableExpr>(E)) {
       recurse = asImpl().checkTemporarilyEscapable(TE);
+    } else if (auto OSE = dyn_cast<ObjCSelectorExpr>(E)) {
+      recurse = asImpl().checkObjCSelector(OSE);
     }
 
     // Error handling validation (via checkTopLevelEffects) happens after
@@ -670,6 +739,8 @@ class EffectsHandlingWalker : public ASTWalker {
       recurse = asImpl().checkForEach(forEach);
     } else if (auto labeled = dyn_cast<LabeledConditionalStmt>(S)) {
       asImpl().noteLabeledConditionalStmt(labeled);
+    } else if (auto defer = dyn_cast<DeferStmt>(S)) {
+      recurse = asImpl().checkDefer(defer);
     }
 
     if (!recurse)
@@ -1113,18 +1184,17 @@ class Classification {
   static Classification
   forDeclRef(ConcreteDeclRef declRef, ConditionalEffectKind conditionalKind,
              PotentialEffectReason reason, SourceLoc loc,
+             bool skipTypeCheck,
              std::optional<EffectKind> onlyEffect = std::nullopt) {
-    ASTContext &ctx = declRef.getDecl()->getASTContext();
-
     Classification result;
     bool considerAsync = !onlyEffect || *onlyEffect == EffectKind::Async;
     bool considerThrows = !onlyEffect || *onlyEffect == EffectKind::Throws;
-    bool considerUnsafe = (!onlyEffect || *onlyEffect == EffectKind::Unsafe) &&
-        ctx.LangOpts.hasFeature(Feature::StrictMemorySafety);
+    bool considerUnsafe = (!onlyEffect || *onlyEffect == EffectKind::Unsafe);
 
     // If we're tracking "unsafe" effects, compute them here.
     if (considerUnsafe) {
-      enumerateUnsafeUses(declRef, loc, /*isCall=*/false, [&](UnsafeUse use) {
+      enumerateUnsafeUses(declRef, loc, /*isCall=*/false, skipTypeCheck,
+                          [&](UnsafeUse use) {
         result.recordUnsafeUse(use);
         return false;
       });
@@ -1332,7 +1402,8 @@ class ApplyClassifier {
     if (isa<SubscriptDecl>(cdr.getDecl()))
       return PotentialEffectReason::forSubscriptAccess();
 
-    assert(isa<VarDecl>(cdr.getDecl()));
+    // Note that declarations other than properties end up with
+    // "property access" effect reasons for historical... reasons.
     return PotentialEffectReason::forPropertyAccess();
   }
 
@@ -1352,8 +1423,7 @@ class ApplyClassifier {
     }
   }
 
-  Classification classifyConformance(Type type,
-                                     ProtocolConformanceRef conformanceRef,
+  Classification classifyConformance(ProtocolConformanceRef conformanceRef,
                                      EffectKind kind) {
     if (conformanceRef.isInvalid())
       return Classification::forInvalidCode();
@@ -1374,8 +1444,7 @@ class ApplyClassifier {
           conditional = ConditionalEffectKind::Always;
 
         // Use the Failure type witness, when present.
-        Type thrownError = conformanceRef.getTypeWitness(
-            type, failureAssocType);
+        Type thrownError = conformanceRef.getTypeWitness(failureAssocType);
         return Classification::forThrows(
             thrownError, conditional,
             /*FIXME*/PotentialEffectReason::forConformance());
@@ -1422,7 +1491,8 @@ class ApplyClassifier {
         module = var->getDeclContext()->getParentModule();
       }
       if (!isLetAccessibleAnywhere(module, var, options)) {
-        return options.contains(ActorReferenceResult::Flags::Preconcurrency);
+        return options.contains(
+            ActorReferenceResult::Flags::CompatibilityDowngrade);
       }
     }
 
@@ -1473,17 +1543,18 @@ class ApplyClassifier {
     if (!member)
       return Classification::forInvalidCode();
 
-    PotentialEffectReason reason =
-        PotentialEffectReason::forPropertyAccess();
-    Classification classification;
+    ConcreteDeclRef declToClassify;
     if (auto getter = getEffectfulGetOnlyAccessor(member)) {
-      reason = getKindOfEffectfulProp(member);
-      classification = Classification::forDeclRef(
-          getter, ConditionalEffectKind::Always, reason, E->getLoc());
-    } else if (isa<SubscriptExpr>(E) || isa<DynamicSubscriptExpr>(E)) {
-      reason = PotentialEffectReason::forSubscriptAccess();
+      declToClassify = getter;
+    } else {
+      declToClassify = member;
     }
 
+    PotentialEffectReason reason = getKindOfEffectfulProp(member);
+    Classification classification = Classification::forDeclRef(
+          declToClassify, ConditionalEffectKind::Always, reason, E->getLoc(),
+          assumedSafeArguments && assumedSafeArguments->contains(E));
+
     classification.setDowngradeToWarning(
         downgradeAsyncAccessToWarning(member.getDecl()));
 
@@ -1492,13 +1563,6 @@ class ApplyClassifier {
         E->isImplicitlyAsync().has_value(), E->isImplicitlyThrows(),
         reason);
 
-    if (!classification.hasUnsafe()) {
-      classification.merge(
-          Classification::forDeclRef(
-            member, ConditionalEffectKind::Always, reason, E->getLoc(),
-            EffectKind::Unsafe));
-    }
-
     if (assumedSafeArguments) {
       // If the declaration we're referencing is explicitly @safe, mark arguments
       // as potentially being safe.
@@ -1522,7 +1586,8 @@ class ApplyClassifier {
 
   Classification classifyDeclRef(ConcreteDeclRef declRef, SourceLoc loc,
                                  bool isImplicitlyAsync,
-                                 bool isImplicitlyThrows) {
+                                 bool isImplicitlyThrows,
+                                 bool ignoreUnsafeType) {
     if (!declRef)
       return Classification::forInvalidCode();
 
@@ -1532,12 +1597,14 @@ class ApplyClassifier {
     if (auto getter = getEffectfulGetOnlyAccessor(declRef)) {
       reason = getKindOfEffectfulProp(declRef);
       classification = Classification::forDeclRef(
-          getter, ConditionalEffectKind::Always, reason, loc);
+          getter, ConditionalEffectKind::Always, reason, loc,
+          ignoreUnsafeType);
     } else if (isa<VarDecl>(declRef.getDecl())) {
       // Handle async let.
       reason = PotentialEffectReason::forAsyncLet();
       classification = Classification::forDeclRef(
-          declRef, ConditionalEffectKind::Always, reason, loc);
+          declRef, ConditionalEffectKind::Always, reason, loc,
+          ignoreUnsafeType);
     }
 
     classification.setDowngradeToWarning(
@@ -1552,18 +1619,12 @@ class ApplyClassifier {
       classification.merge(
           Classification::forDeclRef(
             declRef, ConditionalEffectKind::Always, reason, loc,
-            EffectKind::Unsafe));
+            ignoreUnsafeType, EffectKind::Unsafe));
     }
 
     return classification;
   }
 
-  Classification classifyDeclRef(DeclRefExpr *E) {
-    return classifyDeclRef(
-        E->getDeclRef(), E->getLoc(), E->isImplicitlyAsync().has_value(),
-        E->isImplicitlyThrows());
-  }
-
   Classification classifyThrow(ThrowStmt *S) {
     Expr *thrownValue = S->getSubExpr();
     if (!thrownValue)
@@ -1583,9 +1644,10 @@ class ApplyClassifier {
         PotentialEffectReason::forApply());
   }
 
-  /// Check to see if the given function application throws or is async.
+  /// Check to see if the given function application throws, is async, or
+  /// involves unsafe behavior.
   Classification classifyApply(
-      ApplyExpr *E, 
+      ApplyExpr *E,
       llvm::DenseSet<const Expr *> *assumedSafeArguments
   ) {
     // An apply expression is a potential throw site if the function throws.
@@ -1597,45 +1659,76 @@ class ApplyClassifier {
       assert(!E->isImplicitlyAsync());
     }
 
-    // If this is calling a @safe function, treat local variables as being
-    // safe.
-    if (assumedSafeArguments) {
-      if (auto calleeDecl = E->getCalledValue()) {
-        if (calleeDecl->getExplicitSafety() == ExplicitSafety::Safe) {
-          markArgumentsSafe(E->getArgs(), *assumedSafeArguments);
-        }
-      }
-    }
-
     auto type = E->getFn()->getType();
     if (!type) return Classification::forInvalidCode();
     auto fnType = type->getAs<AnyFunctionType>();
     if (!fnType) return Classification::forInvalidCode();
+    Expr *calleeFn = nullptr;
+    auto fnRef = AbstractFunction::getAppliedFn(E, &calleeFn);
 
-    auto fnRef = AbstractFunction::getAppliedFn(E);
+    auto *args = E->getArgs();
+    return classifyApply(
+        E, fnRef, calleeFn, fnType, args,
+        E->isImplicitlyAsync().has_value(), E->implicitlyThrows(),
+        assumedSafeArguments);
+  }
+
+  /// Check to see if the given function application throws, is async, or
+  /// involves unsafe behavior.
+  Classification classifyApply(
+      ApplyExpr *call,
+      const AbstractFunction &fnRef,
+      Expr *calleeFn,
+      const AnyFunctionType *fnType,
+      ArgumentList *args,
+      bool implicitlyAsync,
+      bool implicitlyThrows,
+      llvm::DenseSet<const Expr *> *assumedSafeArguments
+  ) {
     auto substitutions = fnRef.getSubstitutions();
     const bool hasAnyConformances =
         llvm::any_of(substitutions.getConformances(),
                      [](const ProtocolConformanceRef conformance) {
+                       if (conformance.isInvalid())
+                         return false;
                        auto *requirement = conformance.getProtocol();
                        return !requirement->getInvertibleProtocolKind();
                      });
+    bool hasUnspecifiedSafety =
+        fnRef.getExplicitSafety() == ExplicitSafety::Unspecified;
+
+    if (assumedSafeArguments) {
+      // When calling a function that has no explicitly-written @safe or
+      // @unsafe, we diagnose the safety of the arguments---not the function
+      // itself.
+      if (fnRef.getExplicitSafety() == ExplicitSafety::Unspecified) {
+        if (calleeFn)
+          assumedSafeArguments->insert(calleeFn);
+
+        if (auto appliedSelf = fnRef.getAppliedSelf())
+          assumedSafeArguments->insert(appliedSelf);
+      }
+
+      // If this is calling a @safe function, treat local variables as being
+      // safe.
+      if (fnRef.getExplicitSafety() == ExplicitSafety::Safe) {
+        markArgumentsSafe(args, *assumedSafeArguments);
+      }
+    }
+
+    ASTContext &ctx = fnType->getASTContext();
 
     // If the function doesn't have any effects or conformances, we're done
     // here.
     if (!fnType->isThrowing() &&
-        !E->implicitlyThrows() &&
+        !implicitlyThrows &&
         !fnType->isAsync() &&
-        !E->isImplicitlyAsync() &&
-        !hasAnyConformances) {
+        !implicitlyAsync &&
+        !hasAnyConformances &&
+        fnRef.getExplicitSafety() == ExplicitSafety::Safe) {
       return Classification();
     }
 
-    ASTContext &ctx = type->getASTContext();
-
-    // Decompose the application.
-    auto *args = E->getArgs();
-
     // If any of the arguments didn't type check, fail.
     for (auto arg : *args) {
       auto *argExpr = arg.getExpr();
@@ -1645,7 +1738,7 @@ class ApplyClassifier {
 
     Classification result;
     result.mergeImplicitEffects(
-        ctx, E->isImplicitlyAsync().has_value(), E->implicitlyThrows(),
+        ctx, implicitlyAsync, implicitlyThrows,
         PotentialEffectReason::forApply());
 
     // Downgrade missing 'await' errors for preconcurrency references.
@@ -1654,9 +1747,10 @@ class ApplyClassifier {
         (fnRef.isPreconcurrency() || isContextPreconcurrency()));
 
     auto classifyApplyEffect = [&](EffectKind kind) {
-      if (!fnType->hasEffect(kind) &&
-          !(kind == EffectKind::Async && E->isImplicitlyAsync()) &&
-          !(kind == EffectKind::Throws && E->implicitlyThrows())) {
+      if (kind != EffectKind::Unsafe &&
+          !fnType->hasEffect(kind) &&
+          !(kind == EffectKind::Async && implicitlyAsync) &&
+          !(kind == EffectKind::Throws && implicitlyThrows)) {
         return;
       }
 
@@ -1671,13 +1765,11 @@ class ApplyClassifier {
           if (req.getKind() != RequirementKind::Conformance)
             continue;
 
-          Type type = req.getFirstType().subst(substitutions);
-
           auto conformanceRef = substitutions.lookupConformance(
               req.getFirstType()->getCanonicalType(), req.getProtocolDecl());
           assert(conformanceRef);
 
-          result.merge(classifyConformance(type, conformanceRef, kind));
+          result.merge(classifyConformance(conformanceRef, kind));
         }
 
         // 'ByConformance' is a superset of 'ByClosure', so check for
@@ -1689,6 +1781,22 @@ class ApplyClassifier {
         if (polyKind == PolymorphicEffectKind::ByConformance ||
             polyKind == PolymorphicEffectKind::AsyncSequenceRethrows) {
           LLVM_FALLTHROUGH;
+        } else if (kind == EffectKind::Unsafe) {
+          // For explicitly @unsafe functions, the entire call is considered
+          // unsafe.
+          AbstractFunctionDecl *calleeDecl =
+            fnRef.getKind() == AbstractFunction::Function
+              ? fnRef.getFunction()
+              : nullptr;
+
+          result.merge(
+              Classification::forUnsafe(
+                {
+                  UnsafeUse::forReferenceToUnsafe(
+                    calleeDecl, true, fnRef.getType(), call->getLoc())
+                }
+              ));
+          return;
         } else if (RethrowsDC &&
             fnRef.getKind() == AbstractFunction::Function &&
             isRethrowLikeTypedThrows(fnRef.getFunction())) {
@@ -1716,7 +1824,7 @@ class ApplyClassifier {
           // to fix their code.
           if (kind == EffectKind::Async &&
               fnRef.getKind() == AbstractFunction::Function) {
-            if (auto *ctor = dyn_cast<ConstructorRefCallExpr>(E->getFn())) {
+            if (auto *ctor = dyn_cast<ConstructorRefCallExpr>(call->getFn())) {
               if (ctor->getFn()->isImplicit() && args->isUnlabeledUnary())
                 result.setDowngradeToWarning(true);
             }
@@ -1735,10 +1843,17 @@ class ApplyClassifier {
           return;
         }
 
+        // Can end up with an optional type when dynamically dispatching to
+        // @objc.
+        if (auto optFnType = fnInterfaceType->getOptionalObjectType())
+          fnInterfaceType = optFnType;
+
         // Use the most significant result from the arguments.
         FunctionType *fnSubstType = nullptr;
         if (auto *fnGenericType = fnInterfaceType->getAs<GenericFunctionType>())
           fnSubstType = fnGenericType->substGenericArgs(fnRef.getSubstitutions());
+        else if (fnRef.getSubstitutions())
+          fnSubstType = fnInterfaceType.subst(fnRef.getSubstitutions())->getAs<FunctionType>();
         else
           fnSubstType = fnInterfaceType->getAs<FunctionType>();
 
@@ -1752,10 +1867,17 @@ class ApplyClassifier {
           return;
         }
 
+        AbstractFunctionDecl *calleeDecl =
+          fnRef.getKind() == AbstractFunction::Function
+            ? fnRef.getFunction()
+            : nullptr;
+
         for (unsigned i = 0, e = args->size(); i < e; ++i) {
           Type origParamType = fnRef.getOrigParamInterfaceType(i);
           auto argClassification = classifyArgument(
-              args->getExpr(i), origParamType, fnRef.getSubstitutions(), kind);
+              call, calleeDecl, args->getLabel(i), i,
+              args->getExpr(i), origParamType, fnRef.getSubstitutions(),
+              kind);
 
           // Rethrows is untyped, so adjust the thrown error type.
           if (kind == EffectKind::Throws &&
@@ -1766,6 +1888,17 @@ class ApplyClassifier {
           result.merge(argClassification);
         }
 
+        // The only effect on "self" is unsafe, so check that.
+        if (kind == EffectKind::Unsafe) {
+          if (auto appliedSelf = fnRef.getAppliedSelf()) {
+            Type origParamType = fnRef.getOrigParamSelfType();
+            auto selfClassification = classifyArgument(
+                call, calleeDecl, ctx.Id_self, 0, appliedSelf->getBase(),
+                origParamType, fnRef.getSubstitutions(), kind);
+            result.merge(selfClassification);
+          }
+        }
+
         return;
       }
 
@@ -1807,6 +1940,13 @@ class ApplyClassifier {
     classifyApplyEffect(EffectKind::Throws);
     classifyApplyEffect(EffectKind::Async);
 
+    // If the safety of the callee is unspecified, check the safety of the
+    // arguments specifically.
+    if (hasUnspecifiedSafety &&
+        !(assumedSafeArguments && assumedSafeArguments->contains(call))) {
+      classifyApplyEffect(EffectKind::Unsafe);
+    }
+
     return result;
   }
 
@@ -1995,7 +2135,8 @@ class ApplyClassifier {
         conditional = ConditionalEffectKind::Conditional;
 
       return Classification::forDeclRef(
-          ConcreteDeclRef(fn, subs), conditional, reason, fn->getLoc())
+          ConcreteDeclRef(fn, subs), conditional, reason, fn->getLoc(),
+          /*ignoreUnsafeType=*/false)
             .onlyEffect(kind);
     }
 
@@ -2088,7 +2229,8 @@ class ApplyClassifier {
       if (isEvaluated) {
         classification.merge(
             Self.classifyDeclRef(
-              declRef, loc, isImplicitlyAsync, isImplicitlyThrows
+              declRef, loc, isImplicitlyAsync, isImplicitlyThrows,
+              /*ignoreUnsafeType=*/true
             ).onlyThrowing());
       }
 
@@ -2110,6 +2252,10 @@ class ApplyClassifier {
       return ShouldRecurse;
     }
 
+    ShouldRecurse_t checkDefer(DeferStmt *S) {
+      return ShouldNotRecurse;
+    }
+
     ShouldRecurse_t checkSingleValueStmtExpr(SingleValueStmtExpr *SVE) {
       return ShouldRecurse;
     }
@@ -2132,6 +2278,10 @@ class ApplyClassifier {
       return ShouldRecurse;
     }
 
+    ShouldRecurse_t checkObjCSelector(ObjCSelectorExpr *E) {
+      return ShouldNotRecurse;
+    }
+        
     ConditionalEffectKind checkExhaustiveDoBody(DoCatchStmt *S) {
       // All errors thrown by the do body are caught, but any errors thrown
       // by the catch bodies are bounded by the throwing kind of the do body.
@@ -2255,6 +2405,10 @@ class ApplyClassifier {
       return ShouldRecurse;
     }
 
+    ShouldRecurse_t checkDefer(DeferStmt *S) {
+      return ShouldNotRecurse;
+    }
+
     ShouldRecurse_t checkSingleValueStmtExpr(SingleValueStmtExpr *SVE) {
       return ShouldRecurse;
     }
@@ -2277,6 +2431,10 @@ class ApplyClassifier {
       return ShouldRecurse;
     }
 
+    ShouldRecurse_t checkObjCSelector(ObjCSelectorExpr *E) {
+      return ShouldNotRecurse;
+    }
+
     void visitExprPre(Expr *expr) { return; }
   };
 
@@ -2303,7 +2461,7 @@ class ApplyClassifier {
       return ShouldRecurse;
     }
     ShouldRecurse_t checkUnsafe(UnsafeExpr *E) {
-      return E->isImplicit() ? ShouldRecurse : ShouldNotRecurse;
+      return ShouldNotRecurse;
     }
     ShouldRecurse_t checkTry(TryExpr *E) {
       return ShouldRecurse;
@@ -2329,10 +2487,10 @@ class ApplyClassifier {
                                  bool isEvaluated,
                                  bool isImplicitlyAsync,
                                  bool isImplicitlyThrows) {
-      if (!assumedSafeArguments.contains(expr)) {
-        classification.merge(
-            Self.classifyDeclRef(declRef, loc, false, false).onlyUnsafe());
-      }
+      classification.merge(
+          Self.classifyDeclRef(declRef, loc, false, false,
+                               assumedSafeArguments.contains(expr))
+            .onlyUnsafe());
 
       return ShouldRecurse;
     }
@@ -2354,28 +2512,27 @@ class ApplyClassifier {
       return ShouldNotRecurse;
     }
 
+    ShouldRecurse_t checkDefer(DeferStmt *S) {
+      return ShouldNotRecurse;
+    }
+
     ShouldRecurse_t checkSingleValueStmtExpr(SingleValueStmtExpr *SVE) {
       return ShouldRecurse;
     }
 
     ShouldRecurse_t checkWithSubstitutionMap(Expr *E, SubstitutionMap subs) {
-      if (!assumedSafeArguments.contains(E)) {
-        classification.merge(
-            Classification::forSubstitutionMap(subs, E->getLoc())
-              .onlyUnsafe());
-      }
-
+      classification.merge(
+          Classification::forSubstitutionMap(subs, E->getLoc())
+            .onlyUnsafe());
       return ShouldRecurse;
     }
 
     ShouldRecurse_t checkWithConformances(
         Expr *E,
         ArrayRef<ProtocolConformanceRef> conformances) {
-      if (!assumedSafeArguments.contains(E)) {
-        classification.merge(
-            Classification::forConformances(conformances, E->getLoc())
-              .onlyUnsafe());
-      }
+      classification.merge(
+          Classification::forConformances(conformances, E->getLoc())
+            .onlyUnsafe());
 
       return ShouldRecurse;
     }
@@ -2395,6 +2552,10 @@ class ApplyClassifier {
       return ShouldRecurse;
     }
 
+    ShouldRecurse_t checkObjCSelector(ObjCSelectorExpr *E) {
+      return ShouldNotRecurse;
+    }
+
     void visitExprPre(Expr *expr) { return; }
   };
   
@@ -2458,19 +2619,65 @@ class ApplyClassifier {
     return result;
   }
 
+  /// Determine whether the given expression represents "nil" or
+  /// Optional<T>.none.
+  static bool isNilOrNone(Expr *arg) {
+    // If this argument is `nil` literal, it doesn't cause the call to throw.
+    if (isa<NilLiteralExpr>(arg)) {
+      return !arg->getType()->getOptionalObjectType().isNull();
+    }
+
+    // Neither does 'Optional<T>.none'.
+    if (auto *DSCE = dyn_cast<DotSyntaxCallExpr>(arg)) {
+      if (auto *DE = dyn_cast<DeclRefExpr>(DSCE->getFn())) {
+        auto &ctx = DE->getType()->getASTContext();
+        return DE->getDecl() == ctx.getOptionalNoneDecl();
+      }
+
+      return false;
+    }
+
+    return false;
+  }
+
   /// Classify an argument being passed to a rethrows/reasync function.
   Classification classifyArgument(
-      Expr *arg, Type paramType, SubstitutionMap subs, EffectKind kind) {
+      Expr *call, const Decl* calleeDecl, Identifier argName,
+      unsigned argIndex, Expr *arg, Type paramType, SubstitutionMap subs,
+      EffectKind kind) {
+    // Check for an unsafe argument.
+    if (kind == EffectKind::Unsafe) {
+      if (arg->getType()->isUnsafe()) {
+        // Dig out the underlying argument for special case checks.
+        Expr *underlyingArg = arg;
+        if (auto *defaultArg = dyn_cast<DefaultArgumentExpr>(arg)) {
+          if (defaultArg->isCallerSide()) {
+            underlyingArg = defaultArg->getCallerSideDefaultExpr();
+          }
+        }
+
+        // nil / Optional<T>.none values cannot introduce safety issues because
+        // they don't reference anything.
+        if (isNilOrNone(underlyingArg))
+          return Classification();
+
+        return Classification::forUnsafe({
+          UnsafeUse::forCallArgument(call, calleeDecl, paramType, argName,
+                                     argIndex, arg)
+        });
+      }
+
+      return Classification();
+    }
+
     arg = arg->getValueProvidingExpr();
 
     if (auto *defaultArg = dyn_cast<DefaultArgumentExpr>(arg)) {
       // Special-case a 'nil' default argument, which is known not to throw.
       if (defaultArg->isCallerSide()) {
         auto *callerSideArg = defaultArg->getCallerSideDefaultExpr();
-        if (isa<NilLiteralExpr>(callerSideArg)) {
-          if (callerSideArg->getType()->getOptionalObjectType())
-            return Classification();
-        }
+        if (isNilOrNone(callerSideArg))
+          return Classification();
       }
 
       return classifyArgumentByType(arg->getType(), subs,
@@ -2479,26 +2686,17 @@ class ApplyClassifier {
                                     kind);
     }
 
-    // If this argument is `nil` literal, it doesn't cause the call to throw.
-    if (isa<NilLiteralExpr>(arg)) {
-      if (arg->getType()->getOptionalObjectType())
-        return Classification();
-    }
-
-    // Neither does 'Optional<T>.none'.
-    if (auto *DSCE = dyn_cast<DotSyntaxCallExpr>(arg)) {
-      if (auto *DE = dyn_cast<DeclRefExpr>(DSCE->getFn())) {
-        auto &ctx = paramType->getASTContext();
-        if (DE->getDecl() == ctx.getOptionalNoneDecl())
-          return Classification();
-      }
-    }
+    // If this argument is `nil` literal or Optional<T>.none, it does not
+    // have any effects.
+    if (isNilOrNone(arg))
+      return Classification();
 
     // If the parameter was structurally a tuple, try to look through the
     // various tuple operations.
     if (auto paramTupleType = dyn_cast<TupleType>(paramType.getPointer())) {
       if (auto tuple = dyn_cast<TupleExpr>(arg)) {
-        return classifyTupleArgument(tuple, paramTupleType, subs, kind);
+        return classifyTupleArgument(call, calleeDecl, argName, argIndex,
+                                     tuple, paramTupleType, subs, kind);
       }
 
       if (paramTupleType->getNumElements() != 1) {
@@ -2531,7 +2729,8 @@ class ApplyClassifier {
 
     // Decompose the function reference, then consider the type
     // of the decomposed function.
-    AbstractFunction fn = AbstractFunction::decomposeFunction(arg);
+    AbstractFunction fn = AbstractFunction::decomposeFunction(
+        arg, /*appliedSelf=*/nullptr, /*calleeFn=*/nullptr);
 
     // If it doesn't have function type, we must have invalid code.
     Type argType = fn.getType();
@@ -2550,7 +2749,11 @@ class ApplyClassifier {
   }
 
   /// Classify an argument to a rethrows/reasync function that's a tuple literal.
-  Classification classifyTupleArgument(TupleExpr *tuple,
+  Classification classifyTupleArgument(Expr *call,
+                                       const Decl* calleeDecl,
+                                       Identifier argName,
+                                       unsigned argIndex,
+                                       TupleExpr *tuple,
                                        TupleType *paramTupleType,
                                        SubstitutionMap subs,
                                        EffectKind kind) {
@@ -2559,7 +2762,8 @@ class ApplyClassifier {
 
     Classification result;
     for (unsigned i : indices(tuple->getElements())) {
-      result.merge(classifyArgument(tuple->getElement(i),
+      result.merge(classifyArgument(call, calleeDecl, argName, argIndex,
+                                    tuple->getElement(i),
                                     paramTupleType->getElementType(i),
                                     subs, kind));
     }
@@ -2863,6 +3067,13 @@ class Context {
     return copy;
   }
 
+  /// Form a subcontext that handles all async calls.
+  Context withHandlesAsync() const {
+    Context copy = *this;
+    copy.HandlesAsync = true;
+    return copy;
+  }
+
   Kind getKind() const { return TheKind; }
 
   DeclContext *getDeclContext() const { return DC; }
@@ -3447,9 +3658,9 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
   }
 
   /// Find the top location where we should put the await
-  static Expr *walkToAnchor(Expr *e, llvm::DenseMap<Expr *, Expr *> &parentMap,
-                            bool isInterpolatedString,
-                            bool stopAtAutoClosure) {
+  Expr *walkToAnchor(Expr *e, llvm::DenseMap<Expr *, Expr *> &parentMap,
+                     InterpolatedStringLiteralExpr *interpolatedString,
+                     bool stopAtAutoClosure, EffectKind effect) {
     llvm::SmallPtrSet<Expr *, 4> visited;
     Expr *parent = e;
     Expr *lastParent = e;
@@ -3464,8 +3675,20 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
     if (parent && !isAnchorTooEarly(parent)) {
       return parent;
     }
-    if (isInterpolatedString) {
+    if (interpolatedString) {
       assert(parent == nullptr && "Expected to be at top of expression");
+
+      // If the last parent we found is a call to appendInterpolation, adjust
+      // the anchor location to the interpolated string itself.
+      if (effect == EffectKind::Unsafe) {
+        if (auto callExpr = dyn_cast<CallExpr>(lastParent)) {
+          if (auto calleeDecl = callExpr->getCalledValue()) {
+            if (calleeDecl->getName().matchesRef(Ctx.Id_appendInterpolation))
+              return interpolatedString;
+          }
+        }
+      }
+
       if (ArgumentList *args = lastParent->getArgs()) {
         if (Expr *unaryArg = args->getUnlabeledUnaryExpr())
           return unaryArg;
@@ -3533,6 +3756,12 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
       Self.Flags.set(ContextFlags::InAsyncLet);
     }
 
+    /// Enter a subexpression that's never exected.
+    void enterNonExecuting() {
+      Self.Flags.set(ContextFlags::IsTryCovered);
+      Self.Flags.set(ContextFlags::IsAsyncCovered);
+    }
+
     void refineLocalContext(Context newContext) {
       Self.CurContext = newContext;
     }
@@ -3626,7 +3855,6 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
     }
 
     void preserveCoverageFromUnsafeOperand() {
-      OldFlags.mergeFrom(ContextFlags::HasAnyUnsafeSite, Self.Flags);
       OldFlags.mergeFrom(ContextFlags::HasAnyUnsafe, Self.Flags);
       OldFlags.mergeFrom(ContextFlags::asyncAwaitFlags(), Self.Flags);
       OldFlags.mergeFrom(ContextFlags::throwFlags(), Self.Flags);
@@ -3642,6 +3870,13 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
       OldMaxThrowingKind = std::max(OldMaxThrowingKind, Self.MaxThrowingKind);
     }
 
+    void preserveCoverageFromNonExecutingOperand() {
+      OldFlags.mergeFrom(ContextFlags::asyncAwaitFlags(), Self.Flags);
+      OldFlags.mergeFrom(ContextFlags::throwFlags(), Self.Flags);
+      OldFlags.mergeFrom(ContextFlags::unsafeFlags(), Self.Flags);
+      OldMaxThrowingKind = std::max(OldMaxThrowingKind, Self.MaxThrowingKind);
+    }
+
     void preserveCoverageFromOptionalOrForcedTryOperand() {
       OldFlags.mergeFrom(ContextFlags::asyncAwaitFlags(), Self.Flags);
       OldFlags.mergeFrom(ContextFlags::unsafeFlags(), Self.Flags);
@@ -3801,6 +4036,12 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
     ContextScope scope(*this, /*newContext*/ std::nullopt);
     scope.setCoverageForSingleValueStmtExpr();
     SVE->getStmt()->walk(*this);
+
+    if (auto preamble = SVE->getForExpressionPreamble()) {
+      preamble->ForAccumulatorDecl->walk(*this);
+      preamble->ForAccumulatorBinding->walk(*this);
+    }
+
     scope.preserveCoverageFromSingleValueStmtExpr();
     return ShouldNotRecurse;
   }
@@ -3809,11 +4050,6 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
     auto classification = Classification::forSubstitutionMap(
         subs, E->getLoc());
 
-    // If this expression is covered as a safe argument, drop the unsafe
-    // classification.
-    if (assumedSafeArguments.contains(E))
-      classification = classification.withoutUnsafe();
-
     checkEffectSite(E, /*requiresTry=*/false, classification);
     return ShouldRecurse;
   }
@@ -3824,11 +4060,6 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
     auto classification = Classification::forConformances(
         conformances, E->getLoc());
 
-    // If this expression is covered as a safe argument, drop the unsafe
-    // classification.
-    if (assumedSafeArguments.contains(E))
-      classification = classification.withoutUnsafe();
-
     checkEffectSite(E, /*requiresTry=*/false, classification);
     return ShouldRecurse;
   }
@@ -3853,6 +4084,17 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
     return ShouldRecurse;
   }
 
+  ShouldRecurse_t checkObjCSelector(ObjCSelectorExpr *E) {
+    // Walk the operand.
+    ContextScope scope(*this, CurContext.withHandlesAsync());
+    scope.enterNonExecuting();
+
+    E->getSubExpr()->walk(*this);
+
+    scope.preserveCoverageFromNonExecutingOperand();
+    return ShouldNotRecurse;
+  }
+
   ConditionalEffectKind checkExhaustiveDoBody(DoCatchStmt *S) {
     // This is a context where errors are handled.
     ContextScope scope(*this, CurContext.withHandlesErrors());
@@ -4016,15 +4258,12 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
                                bool isImplicitlyAsync,
                                bool isImplicitlyThrows) {
     if (auto classification = getApplyClassifier().classifyDeclRef(
-          declRef, loc, isImplicitlyAsync, isImplicitlyThrows)) {
+          declRef, loc, isImplicitlyAsync, isImplicitlyThrows,
+          assumedSafeArguments.contains(expr))) {
       // If we aren't evaluating the reference, we only care about 'unsafe'.
       if (!isEvaluated)
         classification = classification.onlyUnsafe();
 
-      // If we're treating this expression as a safe argument, drop 'unsafe'.
-      if (assumedSafeArguments.contains(expr))
-        classification = classification.withoutUnsafe();
-
       auto throwDest = checkEffectSite(
           expr, classification.hasThrows(), classification);
 
@@ -4113,8 +4352,9 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
                  Flags.has(ContextFlags::InAsyncLet))) {
         Expr *expr = E.dyn_cast<Expr*>();
         Expr *anchor = walkToAnchor(expr, parentMap,
-                                    CurContext.isWithinInterpolatedString(),
-                                    /*stopAtAutoClosure=*/true);
+                                    CurContext.getInterpolatedString(),
+                                    /*stopAtAutoClosure=*/true,
+                                    EffectKind::Async);
         if (Flags.has(ContextFlags::StmtExprCoversAwait))
           classification.setDowngradeToWarning(true);
         if (uncoveredAsync.find(anchor) == uncoveredAsync.end())
@@ -4139,8 +4379,9 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
       if (!Flags.has(ContextFlags::IsUnsafeCovered)) {
         Expr *expr = E.dyn_cast<Expr*>();
         Expr *anchor = walkToAnchor(expr, parentMap,
-                                    CurContext.isWithinInterpolatedString(),
-                                    /*stopAtAutoClosure=*/false);
+                                    CurContext.getInterpolatedString(),
+                                    /*stopAtAutoClosure=*/false,
+                                    EffectKind::Unsafe);
 
         // We don't diagnose uncovered unsafe uses within the next/nextElement
         // call, because they're handled already by the for-in loop checking.
@@ -4383,21 +4624,33 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
     // Unsafety in the next/nextElement call is covered by an "unsafe" effect.
     if (classification.hasUnsafe()) {
       // If there is no such effect, complain.
-      if (S->getUnsafeLoc().isInvalid()) {
+      if (S->getUnsafeLoc().isInvalid() &&
+          Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety,
+                                  /*allowMigration=*/true)) {
         auto insertionLoc = S->getPattern()->getStartLoc();
         Ctx.Diags.diagnose(S->getForLoc(), diag::for_unsafe_without_unsafe)
           .fixItInsert(insertionLoc, "unsafe ");
+
+        for (const auto &unsafeUse : classification.getUnsafeUses()) {
+          diagnoseUnsafeUse(unsafeUse);
+        }
       }
-    } else if (S->getUnsafeLoc().isValid() &&
-               Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety)) {
-      // Extraneous "unsafe" on the sequence.
-      Ctx.Diags.diagnose(S->getUnsafeLoc(), diag::no_unsafe_in_unsafe_for)
-        .fixItRemove(S->getUnsafeLoc());
     }
 
     return ShouldRecurse;
   }
 
+  ShouldRecurse_t checkDefer(DeferStmt *S) {
+    // Pretend we're in an 'unsafe'.
+    ContextScope scope(*this, std::nullopt);
+    scope.enterUnsafe(S->getDeferLoc());
+
+    // Walk the call expression. We don't care about the rest.
+    S->getCallExpr()->walk(*this);
+
+    return ShouldNotRecurse;
+  }
+
   void diagnoseRedundantTry(AnyTryExpr *E) const {
     if (auto *SVE = SingleValueStmtExpr::tryDigOutSingleValueStmtExpr(E)) {
       // For an if/switch expression, produce a tailored warning.
@@ -4423,19 +4676,35 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
   }
 
   void diagnoseRedundantUnsafe(UnsafeExpr *E) const {
-    if (!Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety))
+    // Ignore implicitly-generated "unsafe" expressions; they're allowed to be
+    // overly conservative.
+    if (E->isImplicit())
       return;
 
+    SourceLoc loc = E->getUnsafeLoc();
+    if (loc.isValid()) {
+      // Silence this warning in the expansion of the _SwiftifyImport macro.
+      // This is a hack because it's tricky to determine when to insert "unsafe".
+      unsigned bufferID = Ctx.SourceMgr.findBufferContainingLoc(loc);
+      if (auto sourceInfo = Ctx.SourceMgr.getGeneratedSourceInfo(bufferID)) {
+        if (sourceInfo->macroName == "_SwiftifyImport")
+          return;
+      }
+    }
+
     if (auto *SVE = SingleValueStmtExpr::tryDigOutSingleValueStmtExpr(E)) {
       // For an if/switch expression, produce a tailored warning.
-      Ctx.Diags.diagnose(E->getUnsafeLoc(),
+      Ctx.Diags.diagnose(loc,
                          diag::effect_marker_on_single_value_stmt,
                          "unsafe", SVE->getStmt()->getKind())
         .highlight(E->getUnsafeLoc());
       return;
     }
 
-    Ctx.Diags.diagnose(E->getUnsafeLoc(), diag::no_unsafe_in_unsafe)
+    Ctx.Diags.diagnose(E->getUnsafeLoc(),
+                       forEachNextCallExprs.contains(E)
+                           ? diag::no_unsafe_in_unsafe_for
+                           : diag::no_unsafe_in_unsafe)
       .fixItRemove(E->getUnsafeLoc());
   }
 
@@ -4530,6 +4799,12 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
           return diag.downgradeToWarning;
         });
 
+    // If there is a single problem, let's attempt to produce a tailed
+    // diagnostic about accessing isolated values outside of their actors.
+    if (errors.size() == 1 &&
+        diagnoseAccessOutsideOfIsolationContext(anchor, errors.front()))
+      return;
+
     Ctx.Diags.diagnose(anchor->getStartLoc(), diag::async_expr_without_await)
       .warnUntilSwiftVersionIf(downgradeToWarning, 6)
       .fixItInsert(loc, insertText)
@@ -4612,12 +4887,84 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
     }
   }
 
+  /// Check whether the given error points to an attempt to access
+  /// an isolated value or call an isolated function from outside
+  /// its actor and diagnose if so.
+  /// \returns true if problem was diagnosed, false otherwise.
+  bool diagnoseAccessOutsideOfIsolationContext(
+      const Expr *anchor, const DiagnosticInfo &errorInfo) const {
+    auto diagnoseAccessOutsideOfActor = [&](SourceLoc loc,
+                                            ConcreteDeclRef declRef,
+                                            bool isCall = false) {
+      auto declIsolation = getActorIsolation(declRef.getDecl());
+
+      // If the access is to a unspecified/nonisolated value, let's diagnose
+      // it with a generic error/warning about expression being `async`.
+      if (declIsolation.isUnspecified() || declIsolation.isNonisolated())
+        return false;
+
+      const auto &[fixItLoc, insertText] =
+          getFixItForUncoveredSite(anchor, "await");
+
+      Ctx.Diags
+          .diagnose(loc, diag::actor_isolated_access_outside_of_actor_context,
+                    declIsolation, declRef.getDecl(), isCall)
+          .warnUntilSwiftVersionIf(errorInfo.downgradeToWarning, 6)
+          .fixItInsert(fixItLoc, insertText)
+          .highlight(anchor->getSourceRange());
+      return true;
+    };
+
+    switch (errorInfo.reason.getKind()) {
+    case PotentialEffectReason::Kind::AsyncLet:
+    case PotentialEffectReason::Kind::PropertyAccess:
+    case PotentialEffectReason::Kind::SubscriptAccess:
+      if (auto *declRef = dyn_cast<DeclRefExpr>(&errorInfo.expr)) {
+        return diagnoseAccessOutsideOfActor(declRef->getLoc(),
+                                            declRef->getDecl());
+      }
+
+      if (auto *memberRef = dyn_cast<MemberRefExpr>(&errorInfo.expr)) {
+        return diagnoseAccessOutsideOfActor(memberRef->getLoc(),
+                                            memberRef->getDecl());
+      }
+
+      if (auto *lookupExpr = dyn_cast<LookupExpr>(&errorInfo.expr)) {
+        return diagnoseAccessOutsideOfActor(lookupExpr->getLoc(),
+                                            lookupExpr->getMember());
+      }
+
+      break;
+
+    case PotentialEffectReason::Kind::Apply: {
+      auto *call = dyn_cast<ApplyExpr>(&errorInfo.expr);
+      if (call && call->getIsolationCrossing()) {
+        if (auto callee =
+                call->getCalledValue(/*skipFunctionConversions=*/true)) {
+          return diagnoseAccessOutsideOfActor(call->getLoc(), callee,
+                                              /*isCall=*/true);
+        }
+      }
+      break;
+    }
+
+    case PotentialEffectReason::Kind::ByClosure:
+    case PotentialEffectReason::Kind::ByDefaultClosure:
+    case PotentialEffectReason::Kind::ByConformance:
+      break;
+    }
+
+    return false;
+  }
+
   void diagnoseUncoveredUnsafeSite(
       const Expr *anchor, ArrayRef<UnsafeUse> unsafeUses) {
+    if (!Ctx.LangOpts.hasFeature(Feature::StrictMemorySafety, /*allowMigration=*/true))
+      return;
+
     const auto &[loc, insertText] = getFixItForUncoveredSite(anchor, "unsafe");
     Ctx.Diags.diagnose(anchor->getStartLoc(), diag::unsafe_without_unsafe)
-      .fixItInsert(loc, insertText)
-      .highlight(anchor->getSourceRange());
+      .fixItInsert(loc, insertText);
     for (const auto &unsafeUse : unsafeUses) {
       diagnoseUnsafeUse(unsafeUse);
     }
diff --git a/lib/Sema/TypeCheckEmbedded.cpp b/lib/Sema/TypeCheckEmbedded.cpp
new file mode 100644
index 0000000000000..96bde91d40663
--- /dev/null
+++ b/lib/Sema/TypeCheckEmbedded.cpp
@@ -0,0 +1,198 @@
+//===--- TypeCheckEmbedded.cpp - Embedded ----------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements type checking support for Embedded Swift.
+//
+//===----------------------------------------------------------------------===//
+
+#include "TypeCheckEmbedded.h"
+#include "swift/AST/ASTContext.h"
+#include "swift/AST/Decl.h"
+#include "swift/AST/DiagnosticsSema.h"
+#include "swift/AST/Effects.h"
+#include "swift/AST/Expr.h"
+#include "swift/AST/ExistentialLayout.h"
+#include "swift/AST/SourceFile.h"
+#include "swift/AST/Types.h"
+#include "swift/Basic/SourceLoc.h"
+#include "swift/Bridging/ASTGen.h"
+
+using namespace swift;
+
+static DiagnosticBehavior
+defaultEmbeddedLimitationForError(const DeclContext *dc, SourceLoc loc) {
+  if (dc->getASTContext().LangOpts.hasFeature(Feature::Embedded))
+    return DiagnosticBehavior::Unspecified;
+
+  return DiagnosticBehavior::Warning;
+}
+
+std::optional<DiagnosticBehavior>
+swift::shouldDiagnoseEmbeddedLimitations(const DeclContext *dc, SourceLoc loc,
+                                         bool wasAlwaysEmbeddedError) {
+  // In Embedded Swift, things that were always errors will still be emitted
+  // as errors. Use "unspecified" so we don't change anything.
+  if (dc->getASTContext().LangOpts.hasFeature(Feature::Embedded) &&
+      wasAlwaysEmbeddedError) {
+    return defaultEmbeddedLimitationForError(dc, loc);
+  }
+
+  // Check one of the Embedded restriction diagnostics that is ignored by
+  // default. If it's still ignored, we won't diagnose anything.
+  // limitations.
+  auto &diags = dc->getASTContext().Diags;
+  if (diags.isIgnoredDiagnostic(diag::untyped_throws_in_embedded_swift.ID))
+    return std::nullopt;
+
+#if SWIFT_BUILD_SWIFT_SYNTAX
+  // If we are not in Embedded Swift, check whether the location we are
+  // diagnosing at is likely to be active when compiling Embedded Swift. If not,
+  // suppress the diagnostic.
+  auto sourceFile = dc->getParentSourceFile();
+  if (!dc->getASTContext().LangOpts.hasFeature(Feature::Embedded) &&
+      sourceFile &&
+      !swift_ASTGen_activeInEmbeddedSwift(sourceFile->getASTContext(),
+                                          sourceFile->getExportedSourceFile(),
+                                          loc)) {
+    return std::nullopt;
+  }
+#endif
+
+  // If this was always an error in Embedded Swift, we aren't in Embedded Swift
+  // now, so downgrade to a warning.
+  if (wasAlwaysEmbeddedError)
+    return DiagnosticBehavior::Warning;
+
+  // Leave it as-is.
+  return DiagnosticBehavior::Unspecified;
+}
+
+/// Determine whether the inner signature is more generic than the outer
+/// signature, ignoring differences that
+static bool isABIMoreGenericThan(GenericSignature innerSig, GenericSignature outerSig) {
+  auto canInnerSig = innerSig.getCanonicalSignature();
+  auto canOuterSig = outerSig.getCanonicalSignature();
+  if (canInnerSig == canOuterSig)
+    return false;
+
+  // The inner signature added generic parameters.
+  if (canOuterSig.getGenericParams().size() !=
+        canInnerSig.getGenericParams().size())
+    return true;
+
+  // Look at the requirements of the inner signature that aren't satisfied
+  // by the outer signature, to see if there are any requirements that aren't
+  // just marker protocols.
+  auto requirements = canInnerSig.requirementsNotSatisfiedBy(canOuterSig);
+  for (const auto &req : requirements) {
+    switch (req.getKind()) {
+    case RequirementKind::Conformance:
+      if (req.getProtocolDecl()->isMarkerProtocol())
+        continue;
+
+      return true;
+
+    case RequirementKind::Superclass:
+    case RequirementKind::Layout:
+    case RequirementKind::SameShape:
+    case RequirementKind::SameType:
+      return true;
+    }
+  }
+
+  return false;
+}
+
+/// Check embedded restrictions in the signature of the given function.
+void swift::checkEmbeddedRestrictionsInSignature(
+    const AbstractFunctionDecl *func) {
+  // If we are not supposed to diagnose Embedded Swift limitations, do nothing.
+  auto behavior = shouldDiagnoseEmbeddedLimitations(func, func->getLoc());
+  if (!behavior)
+    return;
+
+  // Untyped throws is not permitted.
+  SourceLoc throwsLoc = func->getThrowsLoc();
+  if (throwsLoc.isValid() && !func->getThrownTypeRepr() &&
+      !func->hasPolymorphicEffect(EffectKind::Throws)) {
+    diagnoseUntypedThrowsInEmbedded(func, throwsLoc);
+  }
+
+  // If we're in a class, one cannot have a non-final generic function.
+  if (auto classDecl = dyn_cast<ClassDecl>(func->getDeclContext())) {
+    if (!classDecl->isSemanticallyFinal() &&
+        ((isa<FuncDecl>(func) && !func->isSemanticallyFinal()) ||
+         (isa<ConstructorDecl>(func) &&
+          cast<ConstructorDecl>(func)->isRequired())) &&
+        isABIMoreGenericThan(func->getGenericSignature(),
+                             classDecl->getGenericSignature())) {
+      func->diagnose(diag::generic_nonfinal_in_embedded_swift, func,
+                     isa<ConstructorDecl>(func))
+        .limitBehavior(defaultEmbeddedLimitationForError(func, func->getLoc()));
+    }
+  }
+}
+
+void swift::diagnoseUntypedThrowsInEmbedded(
+    const DeclContext *dc, SourceLoc throwsLoc) {
+  // If we are not supposed to diagnose Embedded Swift limitations, do nothing.
+  auto behavior = shouldDiagnoseEmbeddedLimitations(dc, throwsLoc);
+  if (!behavior)
+    return;
+
+  dc->getASTContext().Diags.diagnose(
+      throwsLoc, diag::untyped_throws_in_embedded_swift)
+    .limitBehavior(*behavior)
+    .fixItInsertAfter(throwsLoc, "(<#thrown error type#>)");
+}
+
+void swift::diagnoseGenericMemberOfExistentialInEmbedded(
+    const DeclContext *dc, SourceLoc loc,
+    Type baseType, const ValueDecl *member) {
+  // If we are not supposed to diagnose Embedded Swift limitations, do nothing.
+  auto behavior = shouldDiagnoseEmbeddedLimitations(dc, loc);
+  if (!behavior)
+    return;
+
+  if (isABIMoreGenericThan(
+          member->getInnermostDeclContext()->getGenericSignatureOfContext(),
+          member->getDeclContext()->getGenericSignatureOfContext())) {
+    dc->getASTContext().Diags.diagnose(loc, diag::use_generic_member_of_existential_in_embedded_swift, member,
+        baseType)
+      .limitBehavior(*behavior);
+  }
+}
+
+void swift::diagnoseDynamicCastInEmbedded(
+    const DeclContext *dc, const CheckedCastExpr *cast) {
+  // If we are not supposed to diagnose Embedded Swift limitations, do nothing.
+  auto behavior = shouldDiagnoseEmbeddedLimitations(dc, cast->getLoc());
+  if (!behavior)
+    return;
+
+  // We only care about casts to existential types.
+  Type toType = cast->getCastType()->lookThroughAllOptionalTypes();
+  if (!toType->isAnyExistentialType())
+    return;
+
+  ExistentialLayout layout = toType->getExistentialLayout();
+  for (auto proto : layout.getProtocols()) {
+    if (proto->isMarkerProtocol())
+      continue;
+
+    dc->getASTContext().Diags.diagnose(
+        cast->getLoc(),
+        diag::dynamic_cast_involving_protocol_in_embedded_swift, proto)
+      .limitBehaviorIf(behavior);
+    return;
+  }
+}
diff --git a/lib/Sema/TypeCheckEmbedded.h b/lib/Sema/TypeCheckEmbedded.h
new file mode 100644
index 0000000000000..a6f7bd00991a7
--- /dev/null
+++ b/lib/Sema/TypeCheckEmbedded.h
@@ -0,0 +1,64 @@
+//===--- TypeCheckEmbedded.h - Embedded -------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides type checking support for Embedded Swift.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SEMA_TYPECHECKEMBEDDED_H
+#define SWIFT_SEMA_TYPECHECKEMBEDDED_H
+
+#include <optional>
+
+namespace swift {
+
+class AbstractFunctionDecl;
+class DeclContext;
+struct DiagnosticBehavior;
+class CheckedCastExpr;
+class SourceLoc;
+class Type;
+class ValueDecl;
+
+/// Whether we should diagnose language-level limitations of Embedded Swift
+/// at the given source location, and how.
+///
+/// @param dc The declaration context in which the diagnostic would be emitted.
+/// @param loc The source location at which the diagnostic would be emitted.
+/// @param wasAlwaysEmbeddedError Whether this diagnostic was always an error
+/// in Embedded Swift, which is used to avoid downgrading for
+/// source-compatibility reasons.
+/// @returns `std::nullopt` if no diagnostic should be emitted. Otherwise, a
+/// behavior limit to place on the diagnostic when it is emitted.
+std::optional<DiagnosticBehavior>
+shouldDiagnoseEmbeddedLimitations(const DeclContext *dc, SourceLoc loc,
+                                  bool wasAlwaysEmbeddedError = false);
+
+/// Check embedded restrictions in the signature of the given function.
+void checkEmbeddedRestrictionsInSignature(const AbstractFunctionDecl *func);
+
+/// Diagnose a declaration of typed throws at the given location.
+void diagnoseUntypedThrowsInEmbedded(const DeclContext *dc, SourceLoc throwsLoc);
+
+/// Diagnose references to a generic member via an existential type, which are
+/// not available in Embedded Swift.
+void diagnoseGenericMemberOfExistentialInEmbedded(
+    const DeclContext *dc, SourceLoc loc,
+    Type baseType, const ValueDecl *member);
+
+/// Diagnose dynamic casts (is/as?/as!) to a type, which is not always available
+/// in Embedded Swift.
+void diagnoseDynamicCastInEmbedded(
+    const DeclContext *dc, const CheckedCastExpr *cast);
+
+}
+#endif // SWIFT_SEMA_TYPECHECKEMBEDDED_H
diff --git a/lib/Sema/TypeCheckExpr.cpp b/lib/Sema/TypeCheckExpr.cpp
index 1aa945719cc43..184267a29e2b8 100644
--- a/lib/Sema/TypeCheckExpr.cpp
+++ b/lib/Sema/TypeCheckExpr.cpp
@@ -288,12 +288,7 @@ static Expr *makeBinOp(ASTContext &Ctx, Expr *Op, Expr *LHS, Expr *RHS,
 
   if (auto *ternary = dyn_cast<TernaryExpr>(Op)) {
     // Resolve the ternary expression.
-    if (!Ctx.CompletionCallback) {
-      // In code completion we might call preCheckTarget twice - once for
-      // the first pass and once for the second pass. This is fine since
-      // preCheckTarget is idempotent.
-      assert(!ternary->isFolded() && "already folded if expr in sequence?!");
-    }
+    ASSERT(!ternary->isFolded() && "already folded if expr in sequence?!");
     ternary->setCondExpr(LHS);
     ternary->setElseExpr(RHS);
     return ternary;
@@ -301,12 +296,7 @@ static Expr *makeBinOp(ASTContext &Ctx, Expr *Op, Expr *LHS, Expr *RHS,
 
   if (auto *assign = dyn_cast<AssignExpr>(Op)) {
     // Resolve the assignment expression.
-    if (!Ctx.CompletionCallback) {
-      // In code completion we might call preCheckTarget twice - once for
-      // the first pass and once for the second pass. This is fine since
-      // preCheckTarget is idempotent.
-      assert(!assign->isFolded() && "already folded assign expr in sequence?!");
-    }
+    ASSERT(!assign->isFolded() && "already folded assign expr in sequence?!");
     assign->setDest(LHS);
     assign->setSrc(RHS);
     return assign;
@@ -314,12 +304,7 @@ static Expr *makeBinOp(ASTContext &Ctx, Expr *Op, Expr *LHS, Expr *RHS,
   
   if (auto *as = dyn_cast<ExplicitCastExpr>(Op)) {
     // Resolve the 'as' or 'is' expression.
-    if (!Ctx.CompletionCallback) {
-      // In code completion we might call preCheckTarget twice - once for
-      // the first pass and once for the second pass. This is fine since
-      // preCheckTarget is idempotent.
-      assert(!as->isFolded() && "already folded 'as' expr in sequence?!");
-    }
+    ASSERT(!as->isFolded() && "already folded 'as' expr in sequence?!");
     assert(RHS == as && "'as' with non-type RHS?!");
     as->setSubExpr(LHS);    
     return as;
@@ -327,12 +312,7 @@ static Expr *makeBinOp(ASTContext &Ctx, Expr *Op, Expr *LHS, Expr *RHS,
 
   if (auto *arrow = dyn_cast<ArrowExpr>(Op)) {
     // Resolve the '->' expression.
-    if (!Ctx.CompletionCallback) {
-      // In code completion we might call preCheckTarget twice - once for
-      // the first pass and once for the second pass. This is fine since
-      // preCheckTarget is idempotent.
-      assert(!arrow->isFolded() && "already folded '->' expr in sequence?!");
-    }
+    ASSERT(!arrow->isFolded() && "already folded '->' expr in sequence?!");
     arrow->setArgsExpr(LHS);
     arrow->setResultExpr(RHS);
     return arrow;
@@ -633,6 +613,15 @@ swift::DefaultTypeRequest::evaluate(Evaluator &evaluator,
 }
 
 Expr *TypeChecker::foldSequence(SequenceExpr *expr, DeclContext *dc) {
+  // We may end up running pre-checking multiple times for completion and
+  // pattern type-checking, just use the folded expression if we've already
+  // folded the sequence.
+  // FIXME: We ought to fix these cases to not pre-check multiple times,
+  // strictly speaking it isn't idempotent (e.g for things like
+  // `markDirectCallee`).
+  if (auto *folded = expr->getFoldedExpr())
+    return folded;
+
   // First resolve any unresolved decl references in operator positions.
   for (auto i : indices(expr->getElements())) {
     if (i % 2 == 0)
@@ -765,7 +754,7 @@ Expr *CallerSideDefaultArgExprRequest::evaluate(
   auto paramTy = defaultExpr->getType();
 
   // Re-create the default argument using the location info of the call site.
-  auto *dc = defaultExpr->ContextOrCallerSideExpr.get<DeclContext *>();
+  auto *dc = cast<DeclContext *>(defaultExpr->ContextOrCallerSideExpr);
   auto *initExpr = synthesizeCallerSideDefault(param, defaultExpr, dc);
   assert(dc && "Expected a DeclContext before type-checking caller-side arg");
 
@@ -774,14 +763,30 @@ Expr *CallerSideDefaultArgExprRequest::evaluate(
   if (!TypeChecker::typeCheckParameterDefault(initExpr, dc, paramTy,
                                               param->isAutoClosure(),
                                               /*atCallerSide=*/true)) {
-    if (param->hasDefaultExpr()) {
+    auto isSimpleLiteral = [&]() -> bool {
+      switch (param->getDefaultArgumentKind()) {
+#define MAGIC_IDENTIFIER(NAME, STRING) \
+      case DefaultArgumentKind::NAME: return true;
+#include "swift/AST/MagicIdentifierKinds.def"
+      case DefaultArgumentKind::NilLiteral:
+      case DefaultArgumentKind::EmptyArray:
+      case DefaultArgumentKind::EmptyDictionary:
+        return true;
+      default:
+        return false;
+      }
+    };
+    if (param->hasDefaultExpr() && isSimpleLiteral()) {
       // HACK: If we were unable to type-check the default argument in context,
       // then retry by type-checking it within the parameter decl, which should
       // also fail. This will present the user with a better error message and
       // allow us to avoid diagnosing on each call site.
+      // Note we can't do this for expression macros since name lookup may
+      // differ at the call side vs the declaration. We can however do it for
+      // simple literals.
       transaction.abort();
       (void)param->getTypeCheckedDefaultExpr();
-      assert(ctx.Diags.hadAnyError());
+      ASSERT(ctx.Diags.hadAnyError());
     }
     return new (ctx) ErrorExpr(initExpr->getSourceRange(), paramTy);
   }
diff --git a/lib/Sema/TypeCheckExprObjC.cpp b/lib/Sema/TypeCheckExprObjC.cpp
index 0373ad9259601..0039b0004ba7b 100644
--- a/lib/Sema/TypeCheckExprObjC.cpp
+++ b/lib/Sema/TypeCheckExprObjC.cpp
@@ -342,10 +342,8 @@ std::optional<Type> TypeChecker::checkObjCKeyPathExpr(DeclContext *dc,
         diags.diagnose(componentNameLoc, diag::expr_keypath_non_objc_property,
                        var->getName());
         if (var->getLoc().isValid() && var->getDeclContext()->isTypeContext()) {
-          diags.diagnose(var, diag::make_decl_objc,
-                         var->getDescriptiveKind())
-            .fixItInsert(var->getAttributeInsertionLoc(false),
-                         "@objc ");
+          diags.diagnose(var, diag::make_decl_objc, var)
+              .fixItInsert(var->getAttributeInsertionLoc(false), "@objc ");
         }
       } else {
         // FIXME: Warn about non-KVC-compliant getter/setter names?
diff --git a/lib/Sema/TypeCheckGeneric.cpp b/lib/Sema/TypeCheckGeneric.cpp
index 2f5a84d97373e..2a51bb2253380 100644
--- a/lib/Sema/TypeCheckGeneric.cpp
+++ b/lib/Sema/TypeCheckGeneric.cpp
@@ -21,6 +21,7 @@
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/ExistentialLayout.h"
+#include "swift/AST/InFlightSubstitution.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/ProtocolConformance.h"
@@ -142,7 +143,7 @@ OpaqueResultTypeRequest::evaluate(Evaluator &evaluator,
     for (unsigned i = 0; i < opaqueReprs.size(); ++i) {
       auto *currentRepr = opaqueReprs[i];
 
-      if( auto opaqueReturn = dyn_cast<OpaqueReturnTypeRepr>(currentRepr) ) {
+      if (auto opaqueReturn = dyn_cast<OpaqueReturnTypeRepr>(currentRepr)) {
         // Usually, we resolve the opaque constraint and bail if it isn't a class
         // or existential type (see below). However, in this case we know we will
         // fail, so we can bail early and provide a better diagnostic.
@@ -163,13 +164,13 @@ OpaqueResultTypeRequest::evaluate(Evaluator &evaluator,
         }
       }
 
-      auto *paramType = GenericTypeParamType::getType(opaqueSignatureDepth, i,
-                                                      ctx);
+      auto *paramType = GenericTypeParamType::getOpaqueResultType(
+          opaqueSignatureDepth, i, ctx);
       genericParamTypes.push_back(paramType);
     
       TypeRepr *constraint = currentRepr;
       
-      if (auto opaqueReturn = dyn_cast<OpaqueReturnTypeRepr>(currentRepr)){
+      if (auto opaqueReturn = dyn_cast<OpaqueReturnTypeRepr>(currentRepr)) {
         constraint = opaqueReturn->getConstraint();
       }
       // Try to resolve the constraint repr in the parent decl context. It
@@ -267,16 +268,116 @@ OpaqueResultTypeRequest::evaluate(Evaluator &evaluator,
   return opaqueDecl;
 }
 
-/// Determine whether the given type is \c Self, an associated type of \c Self,
-/// or a concrete type.
-static bool isSelfDerivedOrConcrete(Type protoSelf, Type type) {
-  // Check for a concrete type.
-  if (!type->hasTypeParameter())
-    return true;
+void TypeChecker::checkCircularOpaqueReturnTypeDecl(OpaqueTypeDecl *opaqueDecl) {
+  auto optSubs = opaqueDecl->getUniqueUnderlyingTypeSubstitutions(
+      /*typeCheckFunctionBodies=*/false);
+  if (!optSubs)
+    return;
+
+  auto substitutions = *optSubs;
+
+  // The underlying type can't be defined recursively
+  // in terms of the opaque type itself.
+  for (auto genericParam : opaqueDecl->getOpaqueGenericParams()) {
+    auto underlyingType = Type(genericParam).subst(substitutions);
+
+    // Look through underlying types of other opaque archetypes known to
+    // us. This is not something the type checker is allowed to do in
+    // general, since the intent is that the underlying type is completely
+    // hidden from view at the type system level. However, here we're
+    // trying to catch recursive underlying types before we proceed to
+    // SIL, so we specifically want to erase opaque archetypes just
+    // for the purpose of this check.
+    ReplaceOpaqueTypesWithUnderlyingTypes replacer(
+        opaqueDecl->getDeclContext(),
+        ResilienceExpansion::Maximal,
+        /*isWholeModuleContext=*/false,
+        /*typeCheckFunctionBodies=*/false);
+    InFlightSubstitution IFS(replacer, replacer,
+                             SubstFlags::SubstituteOpaqueArchetypes |
+                             SubstFlags::PreservePackExpansionLevel);
+    auto simplifiedUnderlyingType = underlyingType.subst(IFS);
+
+    auto isSelfReferencing =
+        (IFS.wasLimitReached() ||
+         simplifiedUnderlyingType.findIf([&](Type t) -> bool {
+           if (auto *other = t->getAs<OpaqueTypeArchetypeType>()) {
+             return other->getDecl() == opaqueDecl;
+           }
+           return false;
+         }));
+
+    if (isSelfReferencing) {
+      opaqueDecl->getNamingDecl()->diagnose(
+          diag::opaque_type_self_referential_underlying_type,
+          underlyingType);
+    }
+  }
+}
+
+static bool checkProtocolSelfRequirementsImpl(
+    ASTContext &ctx, ProtocolDecl *proto, ValueDecl *decl,
+    GenericSignature originalSig,
+    GenericSignature effectiveSig,
+    bool downgrade,
+    bool *hasSameTypeRequirement) {
+  if (hasSameTypeRequirement)
+    *hasSameTypeRequirement = false;
+
+  for (auto req : effectiveSig.getRequirements()) {
+    if (req.getKind() == RequirementKind::SameType)
+      if (hasSameTypeRequirement)
+        *hasSameTypeRequirement = true;
+
+    // The conformance of 'Self' to the protocol is okay.
+    if (req.getKind() == RequirementKind::Conformance &&
+        req.getProtocolDecl() == proto &&
+        req.getFirstType()->isEqual(ctx.TheSelfType))
+      continue;
+
+    auto isSelfDerived = [&](Type t) -> bool {
+      return t->getRootGenericParam()->isEqual(ctx.TheSelfType);
+    };
+
+    // If the requirement's subject type is rooted in an inner generic
+    // parameter, this requirement is okay.
+    if (!isSelfDerived(req.getFirstType()))
+      continue;
 
-  if (type->isTypeParameter() &&
-      type->getRootGenericParam()->isEqual(protoSelf))
+    Type firstType = req.getFirstType();
+    Type secondType;
+    if (req.getKind() == RequirementKind::Layout)
+      secondType = ctx.getAnyObjectConstraint();
+    else
+      secondType = req.getSecondType();
+
+    // Self.A.B == <<inner generic parameter>> is OK.
+    if (req.getKind() == RequirementKind::SameType &&
+        secondType->isTypeParameter() &&
+        !isSelfDerived(secondType))
+      continue;
+
+    // Anything else is a new requirement on 'Self', which is not allowed.
+
+    // Downgrade even harder in this case, since the old logic always missed it.
+    if (secondType->hasTypeParameter() && !secondType->isTypeParameter())
+      downgrade = true;
+
+    // Re-sugar the types, since effectiveSig might be canonical.
+    firstType = originalSig->getSugaredType(firstType);
+    secondType = originalSig->getSugaredType(secondType);
+    static_assert((unsigned)RequirementKind::LAST_KIND == 4,
+                  "update %select in diagnostic!");
+
+    ctx.Diags.diagnose(decl, diag::requirement_restricts_self, decl,
+                       firstType.getString(),
+                       static_cast<unsigned>(req.getKind()),
+                       secondType.getString())
+        // FIXME: This should become an unconditional error since violating
+        // this invariant can introduce compiler and run time crashes.
+        .warnUntilFutureSwiftVersionIf(downgrade);
     return true;
+  }
 
   return false;
 }
@@ -284,60 +385,99 @@ static bool isSelfDerivedOrConcrete(Type protoSelf, Type type) {
 // For a generic requirement in a protocol, make sure that the requirement
 // set didn't add any requirements to Self or its associated types.
 void TypeChecker::checkProtocolSelfRequirements(ValueDecl *decl) {
-  // For a generic requirement in a protocol, make sure that the requirement
-  // set didn't add any requirements to Self or its associated types.
+  // Make sure the generic signature of a protocol method doesn't
+  // impose any new requirements on Self or one of its member types.
   if (auto *proto = dyn_cast<ProtocolDecl>(decl->getDeclContext())) {
+    auto *genCtx = decl->getAsGenericContext();
+    ASSERT(genCtx != nullptr);
+
+    // If it's not generic and it doesn't have a where clause, there is
+    // nothing to check.
+    if (!genCtx->getGenericParams() && !genCtx->getTrailingWhereClause())
+      return;
+
     auto &ctx = proto->getASTContext();
-    auto protoSelf = proto->getSelfInterfaceType();
-    auto sig = decl->getInnermostDeclContext()->getGenericSignatureOfContext();
+    auto sig = genCtx->getGenericSignature();
+
+    bool hasSameTypeRequirement = false;
+
+    // Perform the check as it was formerly implemented first, by looking at
+    // the syntactic requirements of the original generic signature.
+    if (checkProtocolSelfRequirementsImpl(ctx, proto, decl, sig, sig,
+                                          /*downgrade=*/false,
+                                          &hasSameTypeRequirement)) {
+      return;
+    }
+
+    // If the generic signature was sufficiently simple, we're done.
+    if (!hasSameTypeRequirement)
+      return;
+
+    // The quick check doesn't catch everything when same-type requirements
+    // are involved, so the correct thing is to build a new signature where
+    // the innermost generic parameters added by the protocol method now have
+    // a non-zero weight. In this signature, any type that can be made
+    // equivalent to a member type of Self will have a reduced type rooted
+    // in Self.
+    SmallVector<GenericTypeParamType *, 2> params;
+    SmallVector<Requirement, 2> reqs;
+
+    auto transformParam = [&](GenericTypeParamType *paramTy)
+        -> GenericTypeParamType * {
+      if (paramTy->getDepth() == sig->getMaxDepth()) {
+        return GenericTypeParamType::get(
+            paramTy->getParamKind(),
+            paramTy->getDepth(),
+            paramTy->getIndex(),
+            /*weight=*/1,
+            paramTy->getValueType(), ctx);
+      }
+
+      return cast<GenericTypeParamType>(paramTy->getCanonicalType());
+    };
+
+    for (auto *paramTy : sig.getGenericParams())
+      params.push_back(transformParam(paramTy));
+
+    auto transformType = [&](Type t) -> Type {
+      return t.transformRec([&](TypeBase *t) -> std::optional<Type> {
+        if (auto *paramTy = dyn_cast<GenericTypeParamType>(t))
+          return transformParam(paramTy);
+
+        return std::nullopt;
+      })->getCanonicalType();
+    };
+
     for (auto req : sig.getRequirements()) {
-      // If one of the types in the requirement is dependent on a non-Self
-      // type parameter, this requirement is okay.
-      if (!isSelfDerivedOrConcrete(protoSelf, req.getFirstType()) ||
-          !isSelfDerivedOrConcrete(protoSelf, req.getSecondType()))
-        continue;
-
-      // The conformance of 'Self' to the protocol is okay.
-      if (req.getKind() == RequirementKind::Conformance &&
-          req.getProtocolDecl() == proto &&
-          req.getFirstType()->is<GenericTypeParamType>())
-        continue;
-
-      static_assert((unsigned)RequirementKind::LAST_KIND == 4,
-                    "update %select in diagnostic!");
-      ctx.Diags.diagnose(decl, diag::requirement_restricts_self, decl,
-                         req.getFirstType().getString(),
-                         static_cast<unsigned>(req.getKind()),
-                         req.getSecondType().getString());
+      if (req.getKind() != RequirementKind::Layout) {
+        reqs.emplace_back(req.getKind(),
+                          transformType(req.getFirstType()),
+                          transformType(req.getSecondType()));
+      } else {
+        reqs.emplace_back(req.getKind(),
+                          transformType(req.getFirstType()),
+                          req.getLayoutConstraint());
+      }
     }
-  }
-}
 
-/// All generic parameters of a generic function must be referenced in the
-/// declaration's type, otherwise we have no way to infer them.
-void TypeChecker::checkReferencedGenericParams(GenericContext *dc) {
-  // Don't do this check for accessors: they're not used directly, so we
-  // never need to infer their generic arguments.  This is mostly a
-  // compile-time optimization, but it also avoids problems with accessors
-  // like 'read' and 'modify' that would arise due to yields not being
-  // part of the formal type.
-  if (isa<AccessorDecl>(dc))
-    return;
+    auto weightedSig = buildGenericSignature(
+        ctx, GenericSignature(), params, reqs, /*allowInverses=*/false);
 
-  auto *genericParams = dc->getGenericParams();
-  auto genericSig = dc->getGenericSignatureOfContext();
-  if (!genericParams)
-    return;
+    // Repeat the check with the new signature.
+    checkProtocolSelfRequirementsImpl(ctx, proto, decl, sig, weightedSig,
+                                      /*downgrade=*/true, nullptr);
+  }
+}
 
-  auto *decl = cast<ValueDecl>(dc->getInnermostDeclarationDeclContext());
+void TypeChecker::collectReferencedGenericParams(Type ty, SmallPtrSet<CanType, 4> &referenced) {
 
   // A helper class to collect referenced generic type parameters
   // and dependent member types.
   class ReferencedGenericTypeWalker : public TypeWalker {
-    SmallPtrSet<CanType, 4> ReferencedGenericParams;
+    SmallPtrSet<CanType, 4> &ReferencedGenericParams;
 
   public:
-    ReferencedGenericTypeWalker() {}
+    ReferencedGenericTypeWalker(SmallPtrSet<CanType, 4> &referenced) : ReferencedGenericParams(referenced) {}
     Action walkToTypePre(Type ty) override {
       // Find generic parameters or dependent member types.
       // Once such a type is found, don't recurse into its children.
@@ -368,24 +508,39 @@ void TypeChecker::checkReferencedGenericParams(GenericContext *dc) {
 
       return Action::Continue;
     }
-
-    SmallPtrSetImpl<CanType> &getReferencedGenericParams() {
-      return ReferencedGenericParams;
-    }
   };
 
+  ty.walk(ReferencedGenericTypeWalker(referenced));
+}
+
+/// All generic parameters of a generic function must be referenced in the
+/// declaration's type, otherwise we have no way to infer them.
+void TypeChecker::checkReferencedGenericParams(GenericContext *dc) {
+  // Don't do this check for accessors: they're not used directly, so we
+  // never need to infer their generic arguments.  This is mostly a
+  // compile-time optimization, but it also avoids problems with accessors
+  // like 'read' and 'modify' that would arise due to yields not being
+  // part of the formal type.
+  if (isa<AccessorDecl>(dc))
+    return;
+
+  auto *genericParams = dc->getGenericParams();
+  auto genericSig = dc->getGenericSignatureOfContext();
+  if (!genericParams)
+    return;
+
+  auto *decl = cast<ValueDecl>(dc->getInnermostDeclarationDeclContext());
+
+  // Set of generic params referenced in parameter types,
+  // return type or requirements.
+  SmallPtrSet<CanType, 4> referencedGenericParams;
+
   // Collect all generic params referenced in parameter types and
   // return type.
-  ReferencedGenericTypeWalker paramsAndResultWalker;
   auto *funcTy = decl->getInterfaceType()->castTo<GenericFunctionType>();
   for (const auto &param : funcTy->getParams())
-    param.getPlainType().walk(paramsAndResultWalker);
-  funcTy->getResult().walk(paramsAndResultWalker);
-
-  // Set of generic params referenced in parameter types,
-  // return type or requirements.
-  auto &referencedGenericParams =
-      paramsAndResultWalker.getReferencedGenericParams();
+    collectReferencedGenericParams(param.getPlainType(), referencedGenericParams);
+  collectReferencedGenericParams(funcTy->getResult(), referencedGenericParams);
 
   // Check if at least one of the generic params in the requirement refers
   // to an already referenced generic parameter. If this is the case,
@@ -409,13 +564,11 @@ void TypeChecker::checkReferencedGenericParams(GenericContext *dc) {
     }
 
     // Collect generic parameter types referenced by types used in a requirement.
-    ReferencedGenericTypeWalker walker;
+    SmallPtrSet<CanType, 4> genericParamsUsedByRequirementTypes;
     if (first && first->hasTypeParameter())
-      first.walk(walker);
+      collectReferencedGenericParams(first, genericParamsUsedByRequirementTypes);
     if (second && second->hasTypeParameter())
-      second.walk(walker);
-    auto &genericParamsUsedByRequirementTypes =
-        walker.getReferencedGenericParams();
+      collectReferencedGenericParams(second, genericParamsUsedByRequirementTypes);
 
     // If at least one of the collected generic types or a root generic
     // parameter of dependent member types is known to be referenced by
@@ -1064,17 +1217,19 @@ CheckGenericArgumentsResult TypeChecker::checkGenericArgumentsForDiagnostics(
       break;
     }
 
-    if (!isolatedConformances.empty()) {
+    if (!isolatedConformances.empty() && signature) {
       // Dig out the original type parameter for the requirement.
       // FIXME: req might not be the right pre-substituted requirement,
       // if this came from a conditional requirement.
-      if (auto failedProtocol =
-              typeParameterProhibitsIsolatedConformance(req.getFirstType(),
-                                                        signature)) {
-          return CheckGenericArgumentsResult::createIsolatedConformanceFailure(
-            req, substReq,
-            TinyPtrVector<ProtocolConformanceRef>(isolatedConformances),
-            *failedProtocol);
+      for (const auto &isolatedConformance : isolatedConformances) {
+        (void)isolatedConformance;
+        if (auto failed =
+                signature->prohibitsIsolatedConformance(req.getFirstType())) {
+            return CheckGenericArgumentsResult::createIsolatedConformanceFailure(
+              req, substReq,
+              TinyPtrVector<ProtocolConformanceRef>(isolatedConformances),
+              failed->second);
+        }
       }
     }
   }
@@ -1181,28 +1336,3 @@ Type StructuralTypeRequest::evaluate(Evaluator &evaluator,
 
   return TypeAliasType::get(typeAlias, parent, genericArgs, result);
 }
-
-std::optional<ProtocolDecl *> swift::typeParameterProhibitsIsolatedConformance(
-    Type type, GenericSignature signature) {
-  if (!type->isTypeParameter())
-    return std::nullopt;
-
-  // An isolated conformance cannot be used in a context where the type
-  // parameter can escape the isolation domain in which the conformance
-  // was formed. To establish this, we look for Sendable or SendableMetatype
-  // requirements on the type parameter itself.
-  ASTContext &ctx = type->getASTContext();
-  auto sendableProto = ctx.getProtocol(KnownProtocolKind::Sendable);
-  auto sendableMetatypeProto =
-      ctx.getProtocol(KnownProtocolKind::SendableMetatype);
-
-  if (sendableProto &&
-      signature->requiresProtocol(type, sendableProto))
-    return sendableProto;
-
-  if (sendableMetatypeProto &&
-          signature->requiresProtocol(type, sendableMetatypeProto))
-    return sendableMetatypeProto;
-
-  return std::nullopt;
-}
diff --git a/lib/Sema/TypeCheckInvertible.cpp b/lib/Sema/TypeCheckInvertible.cpp
index 5132323494ef5..161058d0d63dc 100644
--- a/lib/Sema/TypeCheckInvertible.cpp
+++ b/lib/Sema/TypeCheckInvertible.cpp
@@ -17,11 +17,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "TypeCheckInvertible.h"
+#include "TypeChecker.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/Basic/Assertions.h"
-#include "TypeChecker.h"
+#include "swift/ClangImporter/ClangImporter.h"
 
 using namespace swift;
 
@@ -252,7 +253,7 @@ static void checkInvertibleConformanceCommon(DeclContext *dc,
       // For a type conforming to IP, ensure that the storage conforms to IP.
       switch (IP) {
       case InvertibleProtocolKind::Copyable:
-        if (!type->isNoncopyable())
+        if (type->isCopyable())
           return false;
         break;
       case InvertibleProtocolKind::Escapable:
@@ -316,6 +317,9 @@ bool StorageVisitor::visit(NominalTypeDecl *nominal, DeclContext *dc) {
             dyn_cast_or_null<clang::CXXRecordDecl>(nominal->getClangDecl())) {
       for (auto cxxBase : cxxRecordDecl->bases()) {
         if (auto cxxBaseDecl = cxxBase.getType()->getAsCXXRecordDecl()) {
+          if (importer::isSymbolicCircularBase(cxxRecordDecl, cxxBaseDecl))
+            // Skip circular bases to avoid unbounded recursion
+            continue;
           auto clangModuleLoader = dc->getASTContext().getClangModuleLoader();
           auto importedDecl =
               clangModuleLoader->importDeclDirectly(cxxBaseDecl);
diff --git a/lib/Sema/TypeCheckMacros.cpp b/lib/Sema/TypeCheckMacros.cpp
index 4dc6ec186b685..d15c34929807b 100644
--- a/lib/Sema/TypeCheckMacros.cpp
+++ b/lib/Sema/TypeCheckMacros.cpp
@@ -52,6 +52,8 @@
 #include "swift/Subsystems.h"
 #include "llvm/Config/config.h"
 
+#define DEBUG_TYPE "macros"
+
 using namespace swift;
 
 /// Translate an argument provided as a string literal into an identifier,
@@ -136,7 +138,7 @@ MacroDefinition MacroDefinitionRequest::evaluate(
       SM.getEntireTextForBuffer(sourceFile->getBufferID());
   StringRef macroDeclText =
       SM.extractText(Lexer::getCharSourceRangeFromSourceRange(
-          SM, macro->getSourceRangeIncludingAttrs()));
+          SM, macro->getSourceRange()));
 
   auto checkResult = swift_Macros_checkMacroDefinition(
       &ctx.Diags, sourceFileText, macroDeclText, &externalMacroName,
@@ -183,9 +185,6 @@ MacroDefinition MacroDefinitionRequest::evaluate(
 
   case BridgedBuiltinIsolationMacro:
     return MacroDefinition::forBuiltin(BuiltinMacroKind::IsolationMacro);
-
-  case BridgedBuiltinSwiftSettingsMacro:
-    return MacroDefinition::forBuiltin(BuiltinMacroKind::SwiftSettingsMacro);
   }
 
   // Type-check the macro expansion.
@@ -285,7 +284,7 @@ initializePlugin(ASTContext &ctx, CompilerPlugin *plugin, StringRef libraryPath,
   if (!libraryPath.empty()) {
 #if SWIFT_BUILD_SWIFT_SYNTAX
     llvm::SmallString<128> resolvedLibraryPath;
-    auto fs = ctx.ClangImporterOpts.HasClangIncludeTreeRoot
+    auto fs = ctx.CASOpts.HasImmutableFileSystem
                   ? llvm::vfs::getRealFileSystem()
                   : ctx.SourceMgr.getFileSystem();
     if (auto err = fs->getRealPath(libraryPath, resolvedLibraryPath)) {
@@ -606,9 +605,9 @@ static void diagnoseInvalidDecl(Decl *decl,
       isa<OperatorDecl>(decl) ||
       isa<PrecedenceGroupDecl>(decl) ||
       isa<MacroDecl>(decl) ||
-      isa<ExtensionDecl>(decl)) {
-    decl->diagnose(diag::invalid_decl_in_macro_expansion,
-                   decl->getDescriptiveKind());
+      isa<ExtensionDecl>(decl) ||
+      isa<UsingDecl>(decl)) {
+    decl->diagnose(diag::invalid_decl_in_macro_expansion, decl);
     decl->setInvalid();
 
     if (auto *extension = dyn_cast<ExtensionDecl>(decl)) {
@@ -895,7 +894,7 @@ static CharSourceRange getExpansionInsertionRange(MacroRole role,
                                                   SourceManager &sourceMgr) {
   switch (role) {
   case MacroRole::Accessor: {
-    auto storage = cast<AbstractStorageDecl>(target.get<Decl *>());
+    auto storage = cast<AbstractStorageDecl>(cast<Decl *>(target));
     auto bracesRange = storage->getBracesRange();
 
     // Compute the location where the accessors will be added.
@@ -920,7 +919,7 @@ static CharSourceRange getExpansionInsertionRange(MacroRole role,
   }
   case MacroRole::MemberAttribute: {
     SourceLoc startLoc;
-    if (auto valueDecl = dyn_cast<ValueDecl>(target.get<Decl *>()))
+    if (auto valueDecl = dyn_cast<ValueDecl>(cast<Decl *>(target)))
       startLoc = valueDecl->getAttributeInsertionLoc(/*forModifier=*/true);
     else
       startLoc = target.getStartLoc();
@@ -930,10 +929,10 @@ static CharSourceRange getExpansionInsertionRange(MacroRole role,
   case MacroRole::Member: {
     // Semantically, we insert members right before the closing brace.
     SourceLoc rightBraceLoc;
-    if (auto nominal = dyn_cast<NominalTypeDecl>(target.get<Decl *>())) {
+    if (auto nominal = dyn_cast<NominalTypeDecl>(cast<Decl *>(target))) {
       rightBraceLoc = nominal->getBraces().End;
     } else {
-      auto ext = cast<ExtensionDecl>(target.get<Decl *>());
+      auto ext = cast<ExtensionDecl>(cast<Decl *>(target));
       rightBraceLoc = ext->getBraces().End;
     }
 
@@ -941,7 +940,7 @@ static CharSourceRange getExpansionInsertionRange(MacroRole role,
   }
   case MacroRole::Peer: {
     SourceLoc endLoc = target.getEndLoc();
-    if (auto var = dyn_cast<VarDecl>(target.get<Decl *>())) {
+    if (auto var = dyn_cast<VarDecl>(cast<Decl *>(target))) {
       if (auto binding = var->getParentPatternBinding())
         endLoc = binding->getEndLoc();
     }
@@ -958,7 +957,7 @@ static CharSourceRange getExpansionInsertionRange(MacroRole role,
 
   case MacroRole::Extension: {
     // Extensions are expanded at the top-level.
-    auto *NTD = cast<NominalTypeDecl>(target.get<Decl *>());
+    auto *NTD = cast<NominalTypeDecl>(cast<Decl *>(target));
     auto *topLevelDecl = NTD->getTopmostDeclarationDeclContext();
 
     SourceLoc afterDeclLoc =
@@ -967,7 +966,7 @@ static CharSourceRange getExpansionInsertionRange(MacroRole role,
   }
 
   case MacroRole::Preamble: {
-    if (auto fn = dyn_cast<AbstractFunctionDecl>(target.get<Decl *>())) {
+    if (auto fn = dyn_cast<AbstractFunctionDecl>(cast<Decl *>(target))) {
       return getPreambleMacroOriginalRange(fn);
     }
 
@@ -989,7 +988,7 @@ static CharSourceRange getExpansionInsertionRange(MacroRole role,
     }
 
     // If the function has a body, that's what's being replaced.
-    auto *AFD = cast<AbstractFunctionDecl>(target.get<Decl *>());
+    auto *AFD = cast<AbstractFunctionDecl>(cast<Decl *>(target));
     if (auto range = AFD->getBodySourceRange())
       return Lexer::getCharSourceRangeFromSourceRange(sourceMgr, range);
 
@@ -1040,7 +1039,7 @@ createMacroSourceFile(std::unique_ptr<llvm::MemoryBuffer> buffer,
                dyn_cast_or_null<MacroExpansionExpr>(target.dyn_cast<Expr *>()))
     expansionExpr->getMacroName().getFullName().getString(macroName);
   else if (auto expansionDecl =
-               dyn_cast_or_null<MacroExpansionDecl>(target.get<Decl *>()))
+               dyn_cast_or_null<MacroExpansionDecl>(cast<Decl *>(target)))
     expansionDecl->getMacroName().getFullName().getString(macroName);
 
   // Create a new source buffer with the contents of the expanded macro.
@@ -1063,10 +1062,13 @@ createMacroSourceFile(std::unique_ptr<llvm::MemoryBuffer> buffer,
       /*parsingOpts=*/{}, /*isPrimary=*/false);
   if (auto parentSourceFile = dc->getParentSourceFile())
     macroSourceFile->setImports(parentSourceFile->getImports());
-  else if (auto clangModuleUnit =
-               dyn_cast<ClangModuleUnit>(dc->getModuleScopeContext())) {
-    auto clangModule = clangModuleUnit->getParentModule();
-    performImportResolutionForClangMacroBuffer(*macroSourceFile, clangModule);
+  else if (isa<ClangModuleUnit>(dc->getModuleScopeContext())) {
+    ModuleDecl *originModule = nullptr;
+    // FIXME: remove this workaround once namespace contents are imported into
+    // their corresponding modules
+    if (macroSourceFile->getParentModule()->isClangHeaderImportModule())
+      originModule = cast<Decl *>(target)->getModuleContextForNameLookup();
+    performImportResolutionForClangMacroBuffer(*macroSourceFile, originModule);
   }
   return macroSourceFile;
 }
@@ -1155,14 +1157,6 @@ evaluateFreestandingMacro(FreestandingMacroExpansion *expansion,
           adjustMacroExpansionBufferName(*discriminator));
       break;
     }
-
-    case BuiltinMacroKind::SwiftSettingsMacro: {
-      // Just insert empty scratch space. We are not expanding to anything.
-      std::string scratchSpace;
-      evaluatedSource = llvm::MemoryBuffer::getMemBufferCopy(
-          scratchSpace, adjustMacroExpansionBufferName(*discriminator));
-      break;
-    }
     }
     break;
   }
@@ -1212,6 +1206,11 @@ evaluateFreestandingMacro(FreestandingMacroExpansion *expansion,
 
     PrettyStackTraceFreestandingMacroExpansion debugStack(
         "expanding freestanding macro", expansion);
+    LLVM_DEBUG(
+      llvm::dbgs() << "\nexpanding macro:\n";
+      macro->print(llvm::dbgs(), PrintOptions::printEverything());
+      llvm::dbgs() << "\n";
+    );
 
     // Builtin macros are handled via ASTGen.
     auto *astGenSourceFile = sourceFile->getExportedSourceFile();
@@ -1221,7 +1220,7 @@ evaluateFreestandingMacro(FreestandingMacroExpansion *expansion,
     BridgedStringRef evaluatedSourceOut{nullptr, 0};
     assert(!externalDef.isError());
     swift_Macros_expandFreestandingMacro(
-        &ctx.Diags, externalDef.get(), discriminator->c_str(),
+        ctx, externalDef.get(), discriminator->c_str(),
         getRawMacroRole(macroRole), astGenSourceFile,
         expansion->getSourceRange().Start.getOpaquePointerValue(),
         &evaluatedSourceOut);
@@ -1280,9 +1279,6 @@ std::optional<unsigned> swift::expandMacroExpr(MacroExpansionExpr *mee) {
       expandedExpr = new (ctx) CurrentContextIsolationExpr(
           macroBufferRange.getStart(), expandedType);
       break;
-
-    case BuiltinMacroKind::SwiftSettingsMacro:
-      break;
     }
   }
 
@@ -1396,6 +1392,12 @@ static SourceFile *evaluateAttachedMacro(MacroDecl *macro, Decl *attachedTo,
     }
   }
 
+  // Macros are so spectacularly not valid in an `@abi` attribute that we cannot
+  // even attempt to expand them.
+  if (!ABIRoleInfo(attachedTo).providesAPI()) {
+    return nullptr;
+  }
+
   ASTContext &ctx = dc->getASTContext();
 
   auto moduleDecl = dc->getParentModule();
@@ -1495,7 +1497,6 @@ static SourceFile *evaluateAttachedMacro(MacroDecl *macro, Decl *attachedTo,
     switch (macroDef.getBuiltinKind()) {
     case BuiltinMacroKind::ExternalMacro:
     case BuiltinMacroKind::IsolationMacro:
-    case BuiltinMacroKind::SwiftSettingsMacro:
       // FIXME: Error here.
       return nullptr;
     }
@@ -1536,6 +1537,18 @@ static SourceFile *evaluateAttachedMacro(MacroDecl *macro, Decl *attachedTo,
     auto *astGenAttrSourceFile = attrSourceFile->getExportedSourceFile();
     if (!astGenAttrSourceFile)
       return nullptr;
+    LLVM_DEBUG(
+      StreamPrinter P(llvm::dbgs());
+      llvm::dbgs() << "\nexpanding macro:\n";
+      attr->print(P, PrintOptions::printEverything(), attachedTo);
+      llvm::dbgs() << "\nattached to:\n";
+      attachedTo->print(P, PrintOptions::printEverything());
+      if (parentDecl) {
+        llvm::dbgs() << "\nwith parent:\n";
+        parentDecl->print(P, PrintOptions::printEverything());
+      }
+      llvm::dbgs() << "\n";
+    );
 
     auto *astGenDeclSourceFile = declSourceFile->getExportedSourceFile();
     if (!astGenDeclSourceFile)
@@ -1564,7 +1577,7 @@ static SourceFile *evaluateAttachedMacro(MacroDecl *macro, Decl *attachedTo,
     BridgedStringRef evaluatedSourceOut{nullptr, 0};
     assert(!externalDef.isError());
     swift_Macros_expandAttachedMacro(
-        &ctx.Diags, externalDef.get(), discriminator->c_str(),
+        ctx, externalDef.get(), discriminator->c_str(),
         extendedType.c_str(), conformanceList.c_str(), getRawMacroRole(role),
         astGenAttrSourceFile, attr->AtLoc.getOpaquePointerValue(),
         astGenDeclSourceFile, startLoc.getOpaquePointerValue(),
@@ -1648,7 +1661,6 @@ static SourceFile *evaluateAttachedMacro(MacroDecl *macro,
     switch (macroDef.getBuiltinKind()) {
     case BuiltinMacroKind::ExternalMacro:
     case BuiltinMacroKind::IsolationMacro:
-    case BuiltinMacroKind::SwiftSettingsMacro:
       // FIXME: Error here.
       return nullptr;
     }
@@ -1687,6 +1699,14 @@ static SourceFile *evaluateAttachedMacro(MacroDecl *macro,
 #if SWIFT_BUILD_SWIFT_SYNTAX
     PrettyStackTraceExpr debugStack(
       ctx, "expanding attached macro", attachedTo);
+    LLVM_DEBUG(
+      StreamPrinter P(llvm::dbgs());
+      llvm::dbgs() << "\nexpanding macro:\n";
+      attr->print(P, PrintOptions::printEverything(), nullptr);
+      llvm::dbgs() << "\nattached to:\n";
+      attachedTo->print(P, PrintOptions::printEverything());
+      llvm::dbgs() << "\n";
+    );
 
     auto *astGenAttrSourceFile = attrSourceFile->getExportedSourceFile();
     if (!astGenAttrSourceFile)
@@ -1700,7 +1720,7 @@ static SourceFile *evaluateAttachedMacro(MacroDecl *macro,
     BridgedStringRef evaluatedSourceOut{nullptr, 0};
     assert(!externalDef.isError());
     swift_Macros_expandAttachedMacro(
-        &ctx.Diags, externalDef.get(), discriminator->c_str(),
+        ctx, externalDef.get(), discriminator->c_str(),
         "", "", getRawMacroRole(role),
         astGenAttrSourceFile, attr->AtLoc.getOpaquePointerValue(),
         astGenClosureSourceFile, startLoc.getOpaquePointerValue(),
@@ -1843,9 +1863,8 @@ std::optional<unsigned> swift::expandAccessors(AbstractStorageDecl *storage,
   // property into a computed one without telling us pre-expansion. Produce
   // an error to prevent this.
   if (expectObservers && foundNonObservingAccessorInMacro) {
-    storage->diagnose(
-        diag::macro_nonobserver_unexpected_in_expansion, macro->getName(),
-        foundNonObservingAccessorInMacro->getDescriptiveKind());
+    storage->diagnose(diag::macro_nonobserver_unexpected_in_expansion, macro,
+                      foundNonObservingAccessorInMacro);
   }
 
   // We expected to get a non-observing accessor, but there isn't one (from
@@ -1903,8 +1922,6 @@ ArrayRef<unsigned> ExpandPreambleMacroRequest::evaluate(
 std::optional<unsigned>
 ExpandBodyMacroRequest::evaluate(Evaluator &evaluator,
                                  AnyFunctionRef fn) const {
-  auto *dc = fn.getAsDeclContext();
-  auto &ctx = dc->getASTContext();
   std::optional<unsigned> bufferID;
   fn.forEachAttachedMacro(
       MacroRole::Body,
@@ -1913,18 +1930,6 @@ ExpandBodyMacroRequest::evaluate(Evaluator &evaluator,
         if (bufferID)
           return;
 
-        // '@Task' is gated behind the 'ConcurrencySyntaxSugar'
-        // experimental feature.
-        if (macro->getParentModule()->getName().is("_Concurrency") &&
-            macro->getBaseIdentifier().is("Task") &&
-            !ctx.LangOpts.hasFeature(Feature::ConcurrencySyntaxSugar)) {
-          ctx.Diags.diagnose(
-              customAttr->getLocation(),
-              diag::experimental_macro,
-              macro->getName());
-          return;
-        }
-
         SourceFile * macroSourceFile = nullptr;
         if (auto *fnDecl = fn.getAbstractFunctionDecl()) {
           macroSourceFile = ::evaluateAttachedMacro(
@@ -2148,8 +2153,8 @@ std::optional<unsigned> swift::expandExtensions(CustomAttr *attr,
     for (auto i : inheritedTypes.getIndices()) {
       auto constraint =
           TypeResolution::forInterface(
-              extension->getDeclContext(),
-              TypeResolverContext::GenericRequirement,
+              extension,
+              TypeResolverContext::Inherited,
               /*unboundTyOpener*/ nullptr,
               /*placeholderHandler*/ nullptr,
               /*packElementOpener*/ nullptr)
diff --git a/lib/Sema/TypeCheckMacros.h b/lib/Sema/TypeCheckMacros.h
index 3be6fd2b3f79d..bd10751b3e0fa 100644
--- a/lib/Sema/TypeCheckMacros.h
+++ b/lib/Sema/TypeCheckMacros.h
@@ -1,4 +1,4 @@
-//===--- TypeCheckConcurrency.h - Concurrency -------------------*- C++ -*-===//
+//===--- TypeCheckMacros.h - Macros -----------------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
diff --git a/lib/Sema/TypeCheckNameLookup.cpp b/lib/Sema/TypeCheckNameLookup.cpp
index 5eb91532f8815..83d777d7f10d2 100644
--- a/lib/Sema/TypeCheckNameLookup.cpp
+++ b/lib/Sema/TypeCheckNameLookup.cpp
@@ -21,6 +21,7 @@
 #include "TypoCorrection.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/ExistentialLayout.h"
+#include "swift/AST/ImportCache.h"
 #include "swift/AST/Initializer.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/NameLookupRequests.h"
@@ -265,7 +266,7 @@ convertToUnqualifiedLookupOptions(NameLookupOptions options) {
 static void synthesizeCodingKeysIfNeededForUnqualifiedLookup(ASTContext &ctx,
                                                              DeclContext *dc,
                                                              DeclNameRef name) {
-  if (name.getBaseIdentifier() != ctx.Id_CodingKeys)
+  if (!name.isSimpleName(ctx.Id_CodingKeys))
     return;
 
   for (auto typeCtx = dc->getInnermostTypeContext(); typeCtx != nullptr;
@@ -324,9 +325,6 @@ TypeChecker::lookupUnqualifiedType(DeclContext *dc, DeclNameRef name,
                                    NameLookupOptions options) {
   auto &ctx = dc->getASTContext();
 
-  // HACK: Synthesize CodingKeys if needed.
-  synthesizeCodingKeysIfNeededForUnqualifiedLookup(ctx, dc, name);
-
   auto ulOptions = convertToUnqualifiedLookupOptions(options) |
                    UnqualifiedLookupFlags::TypeLookup;
   {
@@ -335,8 +333,15 @@ TypeChecker::lookupUnqualifiedType(DeclContext *dc, DeclNameRef name,
         name, dc, loc,
         ulOptions - UnqualifiedLookupFlags::AllowProtocolMembers);
 
-    auto lookup =
-        evaluateOrDefault(ctx.evaluator, UnqualifiedLookupRequest{desc}, {});
+    UnqualifiedLookupRequest req(desc);
+    auto lookup = evaluateOrDefault(ctx.evaluator, req, {});
+
+    // HACK: Try synthesize CodingKeys if we got an empty result.
+    if (lookup.allResults().empty() && name.isSimpleName(ctx.Id_CodingKeys)) {
+      synthesizeCodingKeysIfNeededForUnqualifiedLookup(ctx, dc, name);
+      lookup = evaluateOrDefault(ctx.evaluator, req, {});
+    }
+
     if (!lookup.allResults().empty())
       return lookup;
   }
@@ -798,7 +803,50 @@ TypoCorrectionResults::claimUniqueCorrection() {
   return SyntacticTypoCorrection(WrittenName, Loc, uniqueCorrectedName);
 }
 
+/// Returns a sorted vector of modules that are not imported in the given
+/// `SourceFile` and must be in order to make declarations from \p owningModule
+/// visible.
+static SmallVector<ModuleDecl *, 2>
+missingImportsForDefiningModule(ModuleDecl *owningModule, SourceFile &sf) {
+  SmallVector<ModuleDecl *, 2> result;
+  auto &ctx = sf.getASTContext();
+
+  if (auto *declaringModule =
+          owningModule->getDeclaringModuleIfCrossImportOverlay()) {
+    // If the module that owns the declaration is a cross import overlay the
+    // fix-its should suggest importing the declaring and bystanding modules,
+    // not the overlay module.
+    result.push_back(declaringModule);
+
+    SmallVector<Identifier, 2> bystanders;
+    if (owningModule->getRequiredBystandersIfCrossImportOverlay(declaringModule,
+                                                                bystanders)) {
+      for (auto bystander : bystanders) {
+        if (auto bystanderModule = ctx.getModuleByIdentifier(bystander))
+          result.push_back(bystanderModule);
+      }
+    }
+
+    // Remove the modules that are already imported by the source file.
+    auto &importCache = ctx.getImportCache();
+    const DeclContext *dc = &sf;
+    llvm::erase_if(result, [&](ModuleDecl *candidate) {
+      return importCache.isImportedBy(candidate, dc);
+    });
+  } else {
+    // Just the module that owns the declaration is required.
+    result.push_back(owningModule);
+  }
+
+  std::sort(result.begin(), result.end(), [](ModuleDecl *LHS, ModuleDecl *RHS) {
+    return LHS->getNameStr() < RHS->getNameStr();
+  });
+
+  return result;
+}
+
 struct MissingImportFixItInfo {
+  const ModuleDecl *moduleToImport = nullptr;
   OptionSet<ImportFlags> flags;
   std::optional<AccessLevel> accessLevel;
 };
@@ -806,16 +854,21 @@ struct MissingImportFixItInfo {
 class MissingImportFixItCache {
   SourceFile &sf;
   llvm::DenseMap<const ModuleDecl *, MissingImportFixItInfo> infos;
+  bool internalImportsByDefaultEnabled;
 
 public:
-  MissingImportFixItCache(SourceFile &sf) : sf(sf){};
+  MissingImportFixItCache(SourceFile &sf)
+      : sf(sf),
+        internalImportsByDefaultEnabled(sf.getASTContext().LangOpts.hasFeature(
+            Feature::InternalImportsByDefault)) {};
 
-  MissingImportFixItInfo getInfo(const ModuleDecl *mod) {
+  MissingImportFixItInfo getFixItInfo(ModuleDecl *mod) {
     auto existing = infos.find(mod);
     if (existing != infos.end())
       return existing->getSecond();
 
     MissingImportFixItInfo info;
+    info.moduleToImport = mod;
 
     // Find imports of the defining module in other source files and aggregate
     // the attributes and access level usage on those imports collectively. This
@@ -839,40 +892,62 @@ class MissingImportFixItCache {
 
     // Add an appropriate access level as long as it would not conflict with
     // existing imports that lack access levels.
-    if (!foundImport || anyImportHasAccessLevel)
-      info.accessLevel = sf.getMaxAccessLevelUsingImport(mod);
+    auto accessLevelForImport = [&]() -> std::optional<AccessLevel> {
+      auto maxAccessLevel = sf.getMaxAccessLevelUsingImport(mod);
+      if (internalImportsByDefaultEnabled) {
+        if (!foundImport && maxAccessLevel <= AccessLevel::Internal)
+          return std::nullopt;
+      }
+
+      if (foundImport && !anyImportHasAccessLevel)
+        return std::nullopt;
+
+      return maxAccessLevel;
+    };
 
+    info.accessLevel = accessLevelForImport();
     infos[mod] = info;
     return info;
   }
-};
 
-static void diagnoseMissingImportForMember(const ValueDecl *decl,
-                                           SourceFile *sf, SourceLoc loc) {
-  auto &ctx = sf->getASTContext();
-  auto definingModule = decl->getModuleContextForNameLookup();
-  ctx.Diags.diagnose(loc, diag::candidate_from_missing_import,
-                     decl->getDescriptiveKind(), decl->getName(),
-                     definingModule);
-}
+  std::pair<SmallVector<ModuleDecl *, 2>,
+            SmallVector<MissingImportFixItInfo, 2>>
+  getModulesAndFixIts(ModuleDecl *mod) {
+    auto modulesToImport = missingImportsForDefiningModule(mod, sf);
+    SmallVector<MissingImportFixItInfo, 2> fixItInfos;
 
-static void
-diagnoseAndFixMissingImportForMember(const ValueDecl *decl, SourceFile *sf,
-                                     SourceLoc loc,
-                                     MissingImportFixItCache &fixItCache) {
+    for (auto *mod : modulesToImport) {
+      fixItInfos.emplace_back(getFixItInfo(mod));
+    }
 
-  diagnoseMissingImportForMember(decl, sf, loc);
+    return {modulesToImport, fixItInfos};
+  }
+};
 
+static void diagnoseMissingImportsForMember(
+    const ValueDecl *decl, SmallVectorImpl<ModuleDecl *> &modulesToImport,
+    SourceFile *sf, SourceLoc loc, DiagnosticBehavior limit) {
   auto &ctx = sf->getASTContext();
-  auto definingModule = decl->getModuleContextForNameLookup();
-  SourceLoc bestLoc = ctx.Diags.getBestAddImportFixItLoc(decl, sf);
-  if (!bestLoc.isValid())
-    return;
-
-  llvm::SmallString<64> importText;
+  auto count = modulesToImport.size();
+  ASSERT(count > 0);
+
+  if (count > 1) {
+    ctx.Diags
+        .diagnose(loc, diag::member_from_missing_imports_2_or_more, decl,
+                  bool(count > 2), modulesToImport[0], modulesToImport[1])
+        .limitBehavior(limit);
+  } else {
+    ctx.Diags
+        .diagnose(loc, diag::member_from_missing_import, decl,
+                  modulesToImport.front())
+        .limitBehavior(limit);
+  }
+}
 
+static void appendMissingImportFixIt(llvm::SmallString<64> &importText,
+                                     const MissingImportFixItInfo &fixItInfo,
+                                     ASTContext &ctx) {
   // Add flags that must be used consistently on every import in every file.
-  auto fixItInfo = fixItCache.getInfo(definingModule);
   if (fixItInfo.flags.contains(ImportFlags::ImplementationOnly))
     importText += "@_implementationOnly ";
   if (fixItInfo.flags.contains(ImportFlags::WeakLinked))
@@ -890,67 +965,180 @@ diagnoseAndFixMissingImportForMember(const ValueDecl *decl, SourceFile *sf,
       importText += "@_spiOnly ";
   }
 
-  // Add @_spi groups if needed for the declaration.
-  if (decl->isSPI()) {
-    auto spiGroups = decl->getSPIGroups();
-    if (!spiGroups.empty()) {
-      importText += "@_spi(";
-      importText += spiGroups[0].str();
-      importText += ") ";
-    }
-  }
-
   if (explicitAccessLevel) {
     importText += getAccessLevelSpelling(*explicitAccessLevel);
     importText += " ";
   }
 
   importText += "import ";
-  importText += definingModule->getName().str();
+  importText += fixItInfo.moduleToImport->getName().str();
   importText += "\n";
-  ctx.Diags.diagnose(bestLoc, diag::candidate_add_import, definingModule)
-      .fixItInsert(bestLoc, importText);
+}
+
+static void emitMissingImportNoteAndFixIt(
+    SourceLoc loc, const MissingImportFixItInfo &fixItInfo, ASTContext &ctx) {
+  llvm::SmallString<64> importText;
+  appendMissingImportFixIt(importText, fixItInfo, ctx);
+  ctx.Diags
+      .diagnose(loc, diag::candidate_add_import, fixItInfo.moduleToImport)
+      .fixItInsert(loc, importText);
+}
+
+static void
+diagnoseAndFixMissingImportForMember(const ValueDecl *decl, SourceFile *sf,
+                                     SourceLoc loc, DiagnosticBehavior limit,
+                                     MissingImportFixItCache &fixItCache) {
+
+  auto modulesAndFixits =
+      fixItCache.getModulesAndFixIts(decl->getModuleContextForNameLookup());
+  auto modulesToImport = modulesAndFixits.first;
+  auto fixItInfos = modulesAndFixits.second;
+
+  if (modulesToImport.empty())
+    return;
+
+  diagnoseMissingImportsForMember(decl, modulesToImport, sf, loc, limit);
+
+  auto &ctx = sf->getASTContext();
+  SourceLoc bestLoc = ctx.Diags.getBestAddImportFixItLoc(sf);
+  if (!bestLoc.isValid())
+    return;
+
+  for (auto &fixItInfo : fixItInfos) {
+    emitMissingImportNoteAndFixIt(bestLoc, fixItInfo, ctx);
+  }
 }
 
 bool swift::maybeDiagnoseMissingImportForMember(const ValueDecl *decl,
                                                 const DeclContext *dc,
-                                                SourceLoc loc) {
+                                                SourceLoc loc,
+                                                DiagnosticBehavior limit) {
+  // Only diagnose references in source files.
+  auto sf = dc->getParentSourceFile();
+  if (!sf)
+    return false;
+
+  auto &ctx = dc->getASTContext();
+  if (!ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                          /*allowMigration=*/true))
+    return false;
+
+  // Only diagnose members.
+  if (!decl->getDeclContext()->isTypeContext())
+    return false;
+
+  // Only diagnose declarations that haven't been imported.
   if (dc->isDeclImported(decl))
     return false;
 
-  if (dc->getASTContext().LangOpts.EnableCXXInterop) {
+  auto definingModule = decl->getModuleContextForNameLookup();
+  if (ctx.LangOpts.EnableCXXInterop) {
     // With Cxx interop enabled, there are some declarations that always belong
     // to the Clang header import module which should always be implicitly
     // visible. However, that module is not implicitly imported in source files
     // so we need to special case it here and avoid diagnosing.
-    if (decl->getModuleContextForNameLookup()->isClangHeaderImportModule())
+    if (definingModule->isClangHeaderImportModule())
       return false;
   }
 
-  auto sf = dc->getParentSourceFile();
-  if (!sf)
-    return false;
-
-  auto &ctx = dc->getASTContext();
-
   // In lazy typechecking mode just emit the diagnostic immediately without a
   // fix-it since there won't be an opportunity to emit delayed diagnostics.
   if (ctx.TypeCheckerOpts.EnableLazyTypecheck) {
-    diagnoseMissingImportForMember(decl, sf, loc);
+    // Lazy type-checking and migration for MemberImportVisibility are
+    // completely incompatible, so just skip the diagnostic entirely.
+    if (ctx.LangOpts.isMigratingToFeature(Feature::MemberImportVisibility))
+      return false;
+
+    auto modulesToImport = missingImportsForDefiningModule(definingModule, *sf);
+    if (modulesToImport.empty())
+      return false;
+
+    diagnoseMissingImportsForMember(decl, modulesToImport, sf, loc, limit);
     return true;
   }
 
-  sf->addDelayedMissingImportForMemberDiagnostic(decl, loc);
+  sf->addDelayedMissingImportForMemberDiagnostic(decl, loc, limit);
   return false;
 }
 
+void migrateToMemberImportVisibility(SourceFile &sf) {
+  auto delayedDiags = sf.takeDelayedMissingImportForMemberDiagnostics();
+  if (delayedDiags.empty())
+    return;
+
+  auto &ctx = sf.getASTContext();
+  auto bestLoc = ctx.Diags.getBestAddImportFixItLoc(&sf);
+  if (bestLoc.isInvalid())
+    return;
+
+  // Collect the distinct modules that need to be imported and map them
+  // to the collection of declarations which are used in the file and belong
+  // to the module.
+  llvm::SmallVector<ModuleDecl *, 8> modulesToImport;
+  llvm::SmallDenseMap<ModuleDecl *, std::vector<const ValueDecl *>>
+      declsByModuleToImport;
+  for (auto declAndLocs : delayedDiags) {
+    auto decl = declAndLocs.first;
+    auto definingModules = missingImportsForDefiningModule(
+        decl->getModuleContextForNameLookup(), sf);
+
+    for (auto definingModule : definingModules) {
+      auto existing = declsByModuleToImport.find(definingModule);
+      if (existing != declsByModuleToImport.end()) {
+        existing->second.push_back(decl);
+      } else {
+        declsByModuleToImport[definingModule] = {decl};
+        modulesToImport.push_back(definingModule);
+      }
+    }
+  }
+
+  // Emit one warning for each module that needcs to be imported and emit notes
+  // for each reference to a declaration from that module in the file.
+  llvm::sort(modulesToImport, [](ModuleDecl *lhs, ModuleDecl *rhs) -> int {
+    return lhs->getName().compare(rhs->getName());
+  });
+
+  auto fixItCache = MissingImportFixItCache(sf);
+  for (auto mod : modulesToImport) {
+    auto fixItInfo = fixItCache.getFixItInfo(mod);
+    llvm::SmallString<64> importText;
+    appendMissingImportFixIt(importText, fixItInfo, ctx);
+    ctx.Diags.diagnose(bestLoc, diag::add_required_import_for_member, mod)
+        .fixItInsert(bestLoc, importText);
+
+    auto decls = declsByModuleToImport.find(mod);
+    if (decls == declsByModuleToImport.end())
+      continue;
+
+    for (auto decl : decls->second) {
+      auto locs = delayedDiags.find(decl);
+      if (locs == delayedDiags.end())
+        continue;
+
+      for (auto locAndLimit : locs->second) {
+        auto loc = locAndLimit.first;
+        ctx.Diags.diagnose(loc, diag::decl_from_module_used_here, decl, mod);
+      }
+    }
+  }
+}
+
 void swift::diagnoseMissingImports(SourceFile &sf) {
+  // Missing import diagnostics should be emitted differently in "migrate" mode.
+  if (sf.getASTContext().LangOpts.isMigratingToFeature(
+          Feature::MemberImportVisibility)) {
+    migrateToMemberImportVisibility(sf);
+    return;
+  }
+
   auto delayedDiags = sf.takeDelayedMissingImportForMemberDiagnostics();
   auto fixItCache = MissingImportFixItCache(sf);
 
   for (auto declAndLocs : delayedDiags) {
-    for (auto loc : declAndLocs.second) {
-      diagnoseAndFixMissingImportForMember(declAndLocs.first, &sf, loc,
+    for (auto locAndLimit : declAndLocs.second) {
+      auto [loc, limit] = locAndLimit;
+      diagnoseAndFixMissingImportForMember(declAndLocs.first, &sf, loc, limit,
                                            fixItCache);
     }
   }
diff --git a/lib/Sema/TypeCheckObjC.h b/lib/Sema/TypeCheckObjC.h
index 9e74c6f228f11..871e142d93062 100644
--- a/lib/Sema/TypeCheckObjC.h
+++ b/lib/Sema/TypeCheckObjC.h
@@ -41,8 +41,10 @@ class ObjCReason {
 public:
   // The kind of reason.
   enum Kind {
-    /// Has the '@cdecl' attribute.
+    /// Has the '@c' attribute.
     ExplicitlyCDecl,
+    /// Has the '@_cdecl' attribute.
+    ExplicitlyUnderscoreCDecl,
     /// Has the 'dynamic' modifier.
     ExplicitlyDynamic,
     /// Has an explicit '@objc' attribute.
@@ -101,6 +103,7 @@ class ObjCReason {
   static bool requiresAttr(Kind kind) {
     switch (kind) {
     case ExplicitlyCDecl:
+    case ExplicitlyUnderscoreCDecl:
     case ExplicitlyDynamic:
     case ExplicitlyObjC:
     case ExplicitlyObjCMembers:
@@ -153,13 +156,20 @@ class ObjCReason {
   /// requirement, retrieve the requirement.
   ValueDecl *getObjCRequirement() const {
     assert(kind == WitnessToObjC);
-    return declOrAttr.get<ValueDecl *>();
+    return cast<ValueDecl *>(declOrAttr);
   }
 
   DeclAttribute *getAttr() const {
     if (!requiresAttr(kind))
       return nullptr;
-    return declOrAttr.get<DeclAttribute *>();
+    return cast<DeclAttribute *>(declOrAttr);
+  }
+
+  // The foreign language targeted by the context.
+  ForeignLanguage getForeignLanguage() const {
+    if (kind == ExplicitlyCDecl)
+      return ForeignLanguage::C;
+    return ForeignLanguage::ObjectiveC;
   }
 
   void setAttrInvalid() const;
@@ -183,7 +193,7 @@ unsigned getObjCDiagnosticAttrKind(ObjCReason reason);
 
 /// Determine whether the given function can be represented in Objective-C,
 /// and figure out its foreign error convention (if any).
-bool isRepresentableInObjC(
+bool isRepresentableInLanguage(
     const AbstractFunctionDecl *AFD, ObjCReason Reason,
     std::optional<ForeignAsyncConvention> &asyncConvention,
     std::optional<ForeignErrorConvention> &errorConvention);
diff --git a/lib/Sema/TypeCheckPattern.cpp b/lib/Sema/TypeCheckPattern.cpp
index a7083b3798040..11711db491d1f 100644
--- a/lib/Sema/TypeCheckPattern.cpp
+++ b/lib/Sema/TypeCheckPattern.cpp
@@ -90,7 +90,21 @@ filterForEnumElement(DeclContext *DC, SourceLoc UseLoc,
     ValueDecl *e = result.getValueDecl();
     assert(e);
 
-    // Skip if the enum element was referenced as an instance member
+    // We only care about enum members, and must either have an EnumElementDecl,
+    // or a VarDecl which could be wrapping an underlying enum element.
+    // FIXME: We check this up-front to avoid kicking InterfaceTypeRequest
+    // below to help workaround https://github.com/swiftlang/swift/issues/80657
+    // for non-enum cases. The proper fix is to move this filtering logic
+    // into the constraint system.
+    if (!e->getDeclContext()->getSelfEnumDecl())
+      continue;
+
+    auto *EED = dyn_cast<EnumElementDecl>(e);
+    auto *VD = dyn_cast<VarDecl>(e);
+    if (!EED && !VD)
+      continue;
+
+    // Skip if referenced as an instance member
     if (unqualifiedLookup) {
       if (!result.getBaseDecl() ||
           !result.getBaseDecl()->getInterfaceType()->is<MetatypeType>()) {
@@ -98,17 +112,17 @@ filterForEnumElement(DeclContext *DC, SourceLoc UseLoc,
       }
     }
 
-    if (auto *oe = dyn_cast<EnumElementDecl>(e)) {
+    if (EED) {
       // Note that there could be multiple elements with the same
       // name, such results in a re-declaration error, so let's
       // just always pick the last element, just like in `foundConstant`
       // case.
-      foundElement = oe;
+      foundElement = EED;
       continue;
     }
 
-    if (auto *var = dyn_cast<VarDecl>(e)) {
-      foundConstant = var;
+    if (VD) {
+      foundConstant = VD;
       continue;
     }
   }
@@ -124,7 +138,7 @@ static EnumElementDecl *
 lookupUnqualifiedEnumMemberElement(DeclContext *DC, DeclNameRef name,
                                    SourceLoc UseLoc) {
   // FIXME: We should probably pay attention to argument labels someday.
-  name = name.withoutArgumentLabels();
+  name = name.withoutArgumentLabels(DC->getASTContext());
 
   auto lookup =
       TypeChecker::lookupUnqualified(DC, name, UseLoc,
@@ -139,7 +153,7 @@ static LookupResult lookupMembers(DeclContext *DC, Type ty, DeclNameRef name,
     return LookupResult();
 
   // FIXME: We should probably pay attention to argument labels someday.
-  name = name.withoutArgumentLabels();
+  name = name.withoutArgumentLabels(DC->getASTContext());
 
   // Look up the case inside the enum.
   // FIXME: We should be able to tell if this is a private lookup.
@@ -207,6 +221,11 @@ static DeclRefTypeRepr *translateExprToDeclRefTypeRepr(Expr *E, ASTContext &C) {
     }
 
     DeclRefTypeRepr *visitUnresolvedDeclRefExpr(UnresolvedDeclRefExpr *udre) {
+      if (!udre->getName().isSimpleName() ||
+          udre->getName().isOperator() ||
+          udre->getName().isSpecial())
+        return nullptr;
+
       return UnqualifiedIdentTypeRepr::create(C, udre->getNameLoc(),
                                               udre->getName());
     }
@@ -754,13 +773,27 @@ ExprPatternMatchRequest::evaluate(Evaluator &evaluator,
       DeclNameLoc(EP->getLoc()));
   matchOp->setImplicit();
 
+  auto subExpr = EP->getSubExpr();
+
+  // Pull off the outer "unsafe" expression.
+  UnsafeExpr *unsafeExpr = dyn_cast<UnsafeExpr>(subExpr);
+  if (unsafeExpr) {
+    subExpr = unsafeExpr->getSubExpr();
+  }
+
   // Note we use getEndLoc here to have the BinaryExpr source range be the same
   // as the expr pattern source range.
   auto *matchVarRef =
       new (ctx) DeclRefExpr(matchVar, DeclNameLoc(EP->getEndLoc()),
                             /*Implicit=*/true);
-  auto *matchCall = BinaryExpr::create(ctx, EP->getSubExpr(), matchOp,
+  Expr *matchCall = BinaryExpr::create(ctx, subExpr, matchOp,
                                        matchVarRef, /*implicit*/ true);
+
+  // If there was an "unsafe", put it outside of the match call.
+  if (unsafeExpr) {
+    matchCall = new (ctx) UnsafeExpr(unsafeExpr->getLoc(), matchCall);
+  }
+
   return {matchVar, matchCall};
 }
 
@@ -833,7 +866,7 @@ Type PatternTypeRequest::evaluate(Evaluator &evaluator,
     // If we're type checking this pattern in a context that can provide type
     // information, then the lack of type information is not an error.
     if (options & TypeResolutionFlags::AllowUnspecifiedTypes)
-      return Context.TheUnresolvedType;
+      return PlaceholderType::get(Context, P);
 
     Context.Diags.diagnose(P->getLoc(), diag::cannot_infer_type_for_pattern);
     if (auto named = dyn_cast<NamedPattern>(P)) {
@@ -913,7 +946,7 @@ Type PatternTypeRequest::evaluate(Evaluator &evaluator,
       return ErrorType::get(Context);
     }
 
-    return Context.TheUnresolvedType;
+    return PlaceholderType::get(Context, P);
   }
   llvm_unreachable("bad pattern kind!");
 }
@@ -977,7 +1010,6 @@ void repairTupleOrAssociatedValuePatternIfApplicable(
         auto trailingParen = SourceRange(enumElementInnerPat->getEndLoc());
         diag.fixItRemove(leadingParen).fixItRemove(trailingParen);
       }
-      diag.flush();
       addDeclNote();
       enumElementInnerPat = semantic;
     } else {
@@ -1704,41 +1736,18 @@ Pattern *TypeChecker::coercePatternToType(
 /// contextual type.
 void TypeChecker::coerceParameterListToType(ParameterList *P,
                                             AnyFunctionType *FN) {
-
-  // Local function to check if the given type is valid e.g. doesn't have
-  // errors, type variables or unresolved types related to it.
-  auto isValidType = [](Type type) -> bool {
-    return !(type->hasError() || type->hasUnresolvedType());
-  };
-
-  // Local function to check whether type of given parameter
-  // should be coerced to a given contextual type or not.
-  auto shouldOverwriteParam = [&](ParamDecl *param) -> bool {
-    return !isValidType(param->getTypeInContext());
-  };
-
-  auto handleParameter = [&](ParamDecl *param, Type ty, bool forceMutable) {
-    if (forceMutable)
-      param->setSpecifier(ParamDecl::Specifier::InOut);
-
-    // If contextual type is invalid and we have a valid argument type
-    // trying to coerce argument to contextual type would mean erasing
-    // valuable diagnostic information.
-    if (isValidType(ty) || shouldOverwriteParam(param)) {
-      param->setInterfaceType(ty->mapTypeOutOfContext());
-    }
-  };
-
   // Coerce each parameter to the respective type.
   ArrayRef<AnyFunctionType::Param> params = FN->getParams();
   for (unsigned i = 0, e = P->size(); i != e; ++i) {
     auto &param = P->get(i);
     assert(param->getArgumentName().empty() &&
            "Closures cannot have API names");
-    
-    handleParameter(param,
-                    params[i].getParameterType(),
-                    params[i].isInOut());
     assert(!param->isDefaultArgument() && "Closures cannot have default args");
+
+    if (params[i].isInOut())
+      param->setSpecifier(ParamDecl::Specifier::InOut);
+
+    param->setInterfaceType(
+        params[i].getParameterType()->mapTypeOutOfContext());
   }
 }
diff --git a/lib/Sema/TypeCheckPropertyWrapper.cpp b/lib/Sema/TypeCheckPropertyWrapper.cpp
index 849ab5e26f27d..ed8dbea775570 100644
--- a/lib/Sema/TypeCheckPropertyWrapper.cpp
+++ b/lib/Sema/TypeCheckPropertyWrapper.cpp
@@ -73,8 +73,7 @@ static VarDecl *findValueProperty(ASTContext &ctx, NominalTypeDecl *nominal,
     nominal->diagnose(diag::property_wrapper_ambiguous_value_property,
                       nominal->getDeclaredType(), name);
     for (auto var : vars) {
-      var->diagnose(diag::kind_declname_declared_here,
-                    var->getDescriptiveKind(), var->getName());
+      var->diagnose(diag::decl_declared_here_with_kind, var);
     }
     return nullptr;
   }
@@ -109,7 +108,7 @@ static VarDecl *findValueProperty(ASTContext &ctx, NominalTypeDecl *nominal,
 
   // The property may not have any effects right now.
   if (auto getter = var->getEffectfulGetAccessor()) {
-    getter->diagnose(diag::property_wrapper_effectful, getter->getDescriptiveKind());
+    getter->diagnose(diag::property_wrapper_effectful, getter);
     return nullptr;
   }
 
@@ -310,9 +309,7 @@ static SubscriptDecl *findEnclosingSelfSubscript(ASTContext &ctx,
     nominal->diagnose(diag::property_wrapper_ambiguous_enclosing_self_subscript,
                       nominal->getDeclaredType(), subscriptName);
     for (auto subscript : subscripts) {
-      subscript->diagnose(diag::kind_declname_declared_here,
-                          subscript->getDescriptiveKind(),
-                          subscript->getName());
+      subscript->diagnose(diag::decl_declared_here_with_kind, subscript);
     }
     return nullptr;
 
@@ -484,11 +481,15 @@ AttachedPropertyWrappersRequest::evaluate(Evaluator &evaluator,
       continue;
     }
 
+    auto abiRole = ABIRoleInfo(var);
+    bool hasOrIsABI = !abiRole.providesAPI() || !abiRole.providesABI();
+
     // Note: Getting the semantic attrs here would trigger a request cycle.
     auto attachedAttrs = var->getAttrs();
 
     // Check for conflicting attributes.
-    if (attachedAttrs.hasAttribute<LazyAttr>() ||
+    if (hasOrIsABI ||
+        attachedAttrs.hasAttribute<LazyAttr>() ||
         attachedAttrs.hasAttribute<NSCopyingAttr>() ||
         attachedAttrs.hasAttribute<NSManagedAttr>() ||
         (attachedAttrs.hasAttribute<ReferenceOwnershipAttr>() &&
@@ -501,9 +502,11 @@ AttachedPropertyWrappersRequest::evaluate(Evaluator &evaluator,
         whichKind = 1;
       else if (attachedAttrs.hasAttribute<NSManagedAttr>())
         whichKind = 2;
+      else if (hasOrIsABI)
+        whichKind = 3;
       else {
         auto attr = attachedAttrs.getAttribute<ReferenceOwnershipAttr>();
-        whichKind = 2 + static_cast<unsigned>(attr->get());
+        whichKind = 3 + static_cast<unsigned>(attr->get());
       }
       var->diagnose(diag::property_with_wrapper_conflict_attribute,
                     var->getName(), whichKind);
diff --git a/lib/Sema/TypeCheckProtocol.cpp b/lib/Sema/TypeCheckProtocol.cpp
index 6dbe27ac813b2..8ceda41382040 100644
--- a/lib/Sema/TypeCheckProtocol.cpp
+++ b/lib/Sema/TypeCheckProtocol.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,7 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "TypeCheckProtocol.h"
-#include "DerivedConformances.h"
+#include "DerivedConformance/DerivedConformance.h"
 #include "MiscDiagnostics.h"
 #include "OpenedExistentials.h"
 #include "TypeAccessScopeChecker.h"
@@ -33,7 +33,6 @@
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/ASTPrinter.h"
 #include "swift/AST/AccessScope.h"
-#include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
@@ -62,6 +61,7 @@
 #include "swift/Basic/StringExtras.h"
 #include "swift/ClangImporter/ClangModule.h"
 #include "swift/Sema/IDETypeChecking.h"
+#include "swift/Sema/PreparedOverload.h"
 #include "swift/Serialization/SerializedModuleLoader.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Statistic.h"
@@ -289,8 +289,7 @@ static ValueDecl *getStandinForAccessor(AbstractStorageDecl *witness,
     break;
 
 #define OPAQUE_ACCESSOR(ID, KEYWORD)
-#define ACCESSOR(ID) \
-  case AccessorKind::ID:
+#define ACCESSOR(ID, KEYWORD) case AccessorKind::ID:
 #include "swift/AST/AccessorKinds.def"
     llvm_unreachable("unexpected accessor requirement");
   }
@@ -912,8 +911,7 @@ RequirementMatch swift::matchWitness(
 
     case ThrownErrorSubtyping::Subtype:
       // If there were no type parameters, we're done.
-      if (!reqThrownError->hasTypeVariable() &&
-          !reqThrownError->hasTypeParameter())
+      if (!reqThrownError->hasTypeParameter())
         break;
 
       LLVM_FALLTHROUGH;
@@ -1009,7 +1007,8 @@ findMissingGenericRequirementForSolutionFix(
   };
 
   auto selfTy = conformance->getProtocol()->getSelfInterfaceType()
-      .subst(reqEnvironment.getRequirementToWitnessThunkSubs());
+      .subst(reqEnvironment.getRequirementToWitnessThunkSubs())
+        ->mapTypeOutOfContext();
 
   auto sig = conformance->getGenericSignature();
   auto *env = conformance->getGenericEnvironment();
@@ -1035,11 +1034,7 @@ findMissingGenericRequirementForSolutionFix(
           return conformance->getType();
 
         ASSERT(gp->getDepth() > 0);
-        gp = GenericTypeParamType::get(gp->getParamKind(),
-                                       gp->getDepth() - 1,
-                                       gp->getIndex(),
-                                       gp->getValueType(),
-                                       ctx);
+        gp = gp->withDepth(gp->getDepth() - 1);
       }
 
       if (!sig)
@@ -1161,6 +1156,15 @@ swift::matchWitness(WitnessChecker::RequirementEnvironmentCache &reqEnvCache,
       getOrCreateRequirementEnvironment(reqEnvCache, dc, reqSig, proto,
                                         covariantSelf, conformance);
 
+  auto reqSubMap = reqEnvironment.getRequirementToWitnessThunkSubs();
+
+  Type selfTy = proto->getSelfInterfaceType().subst(reqSubMap);
+  if (selfTy->hasError()) {
+    return RequirementMatch(witness, MatchKind::WitnessInvalid,
+                            witnessType, reqEnvironment,
+                            /*optionalAdjustments*/ {});
+  }
+
   // Set up the constraint system for matching.
   auto setup =
       [&]() -> std::tuple<std::optional<RequirementMatch>, Type, Type, Type, Type> {
@@ -1168,31 +1172,23 @@ swift::matchWitness(WitnessChecker::RequirementEnvironmentCache &reqEnvCache,
     // the required type and the witness type.
     cs.emplace(dc, ConstraintSystemFlags::AllowFixes);
 
-    auto syntheticSig = reqEnvironment.getWitnessThunkSignature();
-    auto *syntheticEnv = syntheticSig.getGenericEnvironment();
-    auto reqSubMap = reqEnvironment.getRequirementToWitnessThunkSubs();
-
-    Type selfTy = proto->getSelfInterfaceType().subst(reqSubMap);
-    if (syntheticEnv)
-      selfTy = syntheticEnv->mapTypeIntoContext(selfTy);
-
-
     // Open up the type of the requirement.
-    SmallVector<OpenedType, 4> reqReplacements;
-
     reqLocator =
         cs->getConstraintLocator(req, ConstraintLocator::ProtocolRequirement);
-    reqType =
-        cs->getTypeOfMemberReference(selfTy, req, dc,
-                                     /*isDynamicResult=*/false,
-                                     FunctionRefInfo::doubleBaseNameApply(),
-                                     reqLocator, &reqReplacements)
-            .adjustedReferenceType;
+    auto reqChoice = OverloadChoice::getDecl(
+        selfTy, req, FunctionRefInfo::doubleBaseNameApply());
+    auto reqTypeInfo =
+        cs->getTypeOfMemberReference(reqChoice, dc, reqLocator,
+                                     /*preparedOverload=*/nullptr);
+
+    reqType = reqTypeInfo.adjustedReferenceType;
     reqType = reqType->getRValueType();
 
+    Type reqThrownError = reqTypeInfo.thrownErrorTypeOnAccess;
+
     // For any type parameters we replaced in the witness, map them
     // to the corresponding archetypes in the witness's context.
-    for (const auto &replacement : reqReplacements) {
+    for (const auto &replacement : cs->getOpenedTypes(reqLocator)) {
       auto replacedInReq = Type(replacement.first).subst(reqSubMap);
 
       // If substitution failed, skip the requirement. This only occurs in
@@ -1200,10 +1196,6 @@ swift::matchWitness(WitnessChecker::RequirementEnvironmentCache &reqEnvCache,
       if (replacedInReq->hasError())
         continue;
 
-      if (syntheticEnv) {
-        replacedInReq = syntheticEnv->mapTypeIntoContext(replacedInReq);
-      }
-
       if (auto packType = replacedInReq->getAs<PackType>()) {
         if (auto unwrapped = packType->unwrapSingletonPackExpansion())
           replacedInReq = unwrapped->getPatternType();
@@ -1214,55 +1206,30 @@ swift::matchWitness(WitnessChecker::RequirementEnvironmentCache &reqEnvCache,
     }
 
     // Open up the witness type.
-    SmallVector<OpenedType, 4> witnessReplacements;
-
     witnessType = witness->getInterfaceType();
     witnessLocator =
         cs->getConstraintLocator(req, LocatorPathElt::Witness(witness));
+    DeclReferenceType openWitnessTypeInfo;
+
     if (witness->getDeclContext()->isTypeContext()) {
-      openWitnessType =
-          cs->getTypeOfMemberReference(selfTy, witness, dc,
-                                       /*isDynamicResult=*/false,
-                                       FunctionRefInfo::doubleBaseNameApply(),
-                                       witnessLocator, &witnessReplacements)
-              .adjustedReferenceType;
+      auto witnessChoice = OverloadChoice::getDecl(
+          selfTy, witness, FunctionRefInfo::doubleBaseNameApply());
+      openWitnessTypeInfo =
+          cs->getTypeOfMemberReference(witnessChoice, dc, witnessLocator,
+                                       /*preparedOverload=*/nullptr);
     } else {
-      openWitnessType =
+      auto witnessChoice = OverloadChoice::getDecl(
+          witness, FunctionRefInfo::doubleBaseNameApply());
+      openWitnessTypeInfo =
           cs->getTypeOfReference(
-                witness, FunctionRefInfo::doubleBaseNameApply(), witnessLocator,
-                /*useDC=*/nullptr)
-              .adjustedReferenceType;
+                witnessChoice, /*useDC=*/nullptr, witnessLocator,
+                /*preparedOverload=*/nullptr);
     }
-    openWitnessType = openWitnessType->getRValueType();
-
-    Type reqThrownError;
-    Type witnessThrownError;
-
-    if (auto *witnessASD = dyn_cast<AbstractStorageDecl>(witness)) {
-      auto *reqASD = cast<AbstractStorageDecl>(req);
-
-      // Dig out the thrown error types from the getter so we can compare them
-      // later.
-      auto getThrownErrorType = [](AbstractStorageDecl *asd) -> Type {
-        if (auto getter = asd->getEffectfulGetAccessor()) {
-          if (Type thrownErrorType = getter->getThrownInterfaceType()) {
-            return thrownErrorType;
-          } else if (getter->hasThrows()) {
-            return asd->getASTContext().getErrorExistentialType();
-          }
-        }
-
-        return asd->getASTContext().getNeverType();
-      };
 
-      reqThrownError = getThrownErrorType(reqASD);
-      reqThrownError = cs->openType(reqThrownError, reqReplacements,
-                                    reqLocator);
+    openWitnessType = openWitnessTypeInfo.adjustedReferenceType;
+    openWitnessType = openWitnessType->getRValueType();
 
-      witnessThrownError = getThrownErrorType(witnessASD);
-      witnessThrownError = cs->openType(witnessThrownError, witnessReplacements,
-                                        witnessLocator);
-    }
+    Type witnessThrownError = openWitnessTypeInfo.thrownErrorTypeOnAccess;
 
     return std::make_tuple(std::nullopt, reqType, openWitnessType,
                            reqThrownError, witnessThrownError);
@@ -1494,7 +1461,7 @@ swift::lookupValueWitnesses(DeclContext *DC, ValueDecl *req, bool *ignoringNames
   lookupValueWitnessesViaImplementsAttr(DC, req, witnesses);
 
   auto reqName = req->createNameRef();
-  auto reqBaseName = reqName.withoutArgumentLabels();
+  auto reqBaseName = reqName.withoutArgumentLabels(DC->getASTContext());
 
   // An operator function is the only kind of witness that requires global
   // lookup. However, because global lookup doesn't enter local contexts,
@@ -1667,7 +1634,7 @@ bool WitnessChecker::findBestWitness(
     for (auto match : matches) {
       if (!match.isViable()) {
         checkedMatches.push_back(match);
-      } else if (checkWitness(requirement, match).Kind != CheckKind::Availability) {
+      } else if (!checkWitness(requirement, match).isLessAvailable()) {
         foundCheckedMatch = true;
         checkedMatches.push_back(match);
       }
@@ -1835,13 +1802,56 @@ static bool checkWitnessAccess(DeclContext *dc,
   return false;
 }
 
-bool WitnessChecker::
-checkWitnessAvailability(ValueDecl *requirement,
-                         ValueDecl *witness,
-                         AvailabilityRange *requiredAvailability) {
-  return (!getASTContext().LangOpts.DisableAvailabilityChecking &&
-          !TypeChecker::isAvailabilitySafeForConformance(
-              Proto, requirement, witness, DC, *requiredAvailability));
+static std::optional<AvailabilityConstraint>
+checkWitnessAvailability(const ValueDecl *requirement, const ValueDecl *witness,
+                         const DeclContext *dc,
+                         AvailabilityContext &requiredContext) {
+  auto &ctx = dc->getASTContext();
+  if (ctx.LangOpts.DisableAvailabilityChecking)
+    return std::nullopt;
+
+  // If the requirement is self-witnessing then no need to check availability.
+  if (requirement == witness)
+    return std::nullopt;
+
+  // We assume conformances in implicit code have already been checked for
+  // availability.
+  if (!dc->getParentSourceFile())
+    return std::nullopt;
+
+  assert(dc->getSelfNominalTypeDecl() &&
+         "Must have a nominal or extension context");
+
+  auto requirementAvailability =
+      AvailabilityContext::forDeclSignature(requirement);
+  requiredContext.constrainWithContext(requirementAvailability, ctx);
+
+  // The witness is allowed to be less available than the requirement as long
+  // as it is as available as the overall conformance.
+  auto conformanceAvailability =
+      AvailabilityContext::forDeclSignature(dc->getAsDecl());
+  requiredContext.constrainWithContext(conformanceAvailability, ctx);
+
+  // Relax the requirements for @_spi witnesses by treating the requirement as
+  // if it were introduced at the deployment target. This is not strictly sound
+  // since clients of SPI do not necessarily have the same deployment target as
+  // the module declaring the requirement. However, now that the public
+  // declarations in API libraries are checked according to the minimum possible
+  // deployment target of their clients this relaxation is needed for source
+  // compatibility with some existing code and is reasonably safe for the
+  // majority of cases.
+  if (witness->isSPI())
+    requiredContext.constrainWithContext(
+        AvailabilityContext::forDeploymentTarget(ctx), ctx);
+
+  // In order to maintain source compatibility, universally unavailable decls
+  // are allowed to witness universally unavailable requirements.
+  AvailabilityConstraintFlags flags;
+  flags |= AvailabilityConstraintFlag::
+      AllowUniversallyUnavailableInCompatibleContexts;
+
+  return getAvailabilityConstraintsForDecl(witness, requiredContext, flags)
+      .getPrimaryConstraint();
 }
 
 RequirementCheck WitnessChecker::checkWitness(ValueDecl *requirement,
@@ -1849,34 +1859,31 @@ RequirementCheck WitnessChecker::checkWitness(ValueDecl *requirement,
   if (!match.OptionalAdjustments.empty())
     return CheckKind::OptionalityConflict;
 
-  auto requiredAccessScope = evaluateOrDefault(
+  auto [requiredAccessLevel, mustBeUsableFromInline] = evaluateOrDefault(
       Context.evaluator, ConformanceAccessScopeRequest{DC, Proto},
       std::make_pair(AccessScope::getPublic(), false));
 
   bool isSetter = false;
-  if (checkWitnessAccess(DC, requirement, match.Witness, &isSetter)) {
-    CheckKind kind = (isSetter
-                      ? CheckKind::AccessOfSetter
-                      : CheckKind::Access);
-
-    return RequirementCheck(kind, requiredAccessScope.first);
-  }
+  if (checkWitnessAccess(DC, requirement, match.Witness, &isSetter))
+    return RequirementCheck(requiredAccessLevel, isSetter);
 
-  if (requiredAccessScope.second) {
+  if (mustBeUsableFromInline) {
     bool witnessIsUsableFromInline = match.Witness->getFormalAccessScope(
         DC, /*usableFromInlineAsPublic*/true).isPublic();
     if (!witnessIsUsableFromInline)
       return CheckKind::UsableFromInline;
   }
 
-  auto requiredAvailability = AvailabilityRange::alwaysAvailable();
-  if (checkWitnessAvailability(requirement, match.Witness,
-                               &requiredAvailability)) {
-    return RequirementCheck(CheckKind::Availability, requiredAvailability);
-  }
+  // A witness cannot be less available than its requirement.
+  auto requiredContext = AvailabilityContext::forAlwaysAvailable(Context);
+  if (auto constraint = checkWitnessAvailability(requirement, match.Witness, DC,
+                                                 requiredContext))
+    return RequirementCheck(*constraint, requiredContext);
 
+  // An unavailable requirement cannot be witnessed, just like an unavailable
+  // method cannot be overridden.
   if (requirement->isUnavailable() && match.Witness->getDeclContext() == DC) {
-    return RequirementCheck(CheckKind::Unavailable);
+    return RequirementCheck(CheckKind::RequirementUnavailable);
   }
 
   // A non-failable initializer requirement cannot be satisfied
@@ -1897,27 +1904,6 @@ RequirementCheck WitnessChecker::checkWitness(ValueDecl *requirement,
     }
   }
 
-  if (match.Witness->isUnavailable() && !requirement->isUnavailable()) {
-    auto nominalOrExtensionIsUnavailable = [&]() {
-      if (auto extension = dyn_cast<ExtensionDecl>(DC)) {
-        if (extension->isUnavailable())
-          return true;
-      }
-
-      if (auto adoptingNominal = DC->getSelfNominalTypeDecl()) {
-        if (AvailabilityContext::forDeclSignature(adoptingNominal)
-                .isUnavailable())
-          return true;
-      }
-
-      return false;
-    };
-
-    // Allow unavailable nominals or extension to have unavailable witnesses.
-    if (!nominalOrExtensionIsUnavailable())
-      return CheckKind::WitnessUnavailable;
-  }
-
   // Warn about deprecated default implementations if the requirement is
   // not deprecated, and the conformance is not deprecated.
   bool isDefaultWitness = false;
@@ -2567,13 +2553,6 @@ checkIndividualConformance(NormalProtocolConformance *conformance) {
       ComplainLoc, diag::unchecked_conformance_not_special, ProtoType);
   }
 
-  // Complain if the global-actor-isolated conformances are not enabled.
-  if (conformance->isIsolated() &&
-      !Context.LangOpts.hasFeature(Feature::IsolatedConformances)) {
-    Context.Diags.diagnose(
-        ComplainLoc, diag::isolated_conformance_experimental_feature);
-  }
-  
   bool allowImpliedConditionalConformance = false;
   if (Proto->isSpecificProtocol(KnownProtocolKind::Sendable)) {
     // In -swift-version 5 mode, a conditional conformance to a protocol can imply
@@ -2658,7 +2637,8 @@ checkIndividualConformance(NormalProtocolConformance *conformance) {
   // If we're enforcing strict memory safety and this conformance hasn't
   // opted out, look for safe/unsafe witness mismatches.
   if (conformance->getExplicitSafety() == ExplicitSafety::Unspecified &&
-      Context.LangOpts.hasFeature(Feature::StrictMemorySafety)) {
+      Context.LangOpts.hasFeature(Feature::StrictMemorySafety,
+                                  /*allowMigration=*/true)) {
     // Collect all of the unsafe uses for this conformance.
     SmallVector<UnsafeUse, 2> unsafeUses;
     for (auto requirement: Proto->getMembers()) {
@@ -2702,10 +2682,27 @@ checkIndividualConformance(NormalProtocolConformance *conformance) {
     }
 
     if (!unsafeUses.empty()) {
-      Context.Diags.diagnose(
+      // Primary diagnostic along with a Fix-It to add @unsafe in the appropriate
+      // place.
+      {
+        auto diag = Context.Diags.diagnose(
           conformance->getLoc(), diag::conformance_involves_unsafe,
-          conformance->getType(), Proto)
-      .fixItInsert(conformance->getProtocolNameLoc(), "@unsafe ");
+          conformance->getType(), Proto);
+        
+        // Find the original explicit conformance, where we can add the Fix-It.
+        auto explicitConformance = conformance;
+        while (explicitConformance->getSourceKind() ==
+                  ConformanceEntryKind::Implied) {
+          explicitConformance =
+            explicitConformance->ProtocolConformance::getImplyingConformance();
+        }
+        
+        if (explicitConformance->getSourceKind() ==
+              ConformanceEntryKind::Explicit) {
+          conformance->applyConformanceAttribute(diag, "@unsafe");
+        }
+      }
+
       for (const auto& unsafeUse : unsafeUses)
         diagnoseUnsafeUse(unsafeUse);
     }
@@ -3346,6 +3343,16 @@ static bool hasExplicitGlobalActorAttr(ValueDecl *decl) {
   return !globalActorAttr->first->isImplicit();
 }
 
+/// Determine the isolation of a conformance with a known-isolated value witness.
+static ActorIsolation getConformanceIsolationForIsolatedWitness(
+    NormalProtocolConformance *conformance) {
+  if (auto rawIsolation = conformance->getRawIsolation())
+    return *rawIsolation;
+
+  return inferConformanceIsolation(
+      conformance, /*hasKnownIsolatedWitness=*/true);
+}
+
 std::optional<ActorIsolation>
 ConformanceChecker::checkActorIsolation(ValueDecl *requirement,
                                         ValueDecl *witness,
@@ -3354,9 +3361,8 @@ ConformanceChecker::checkActorIsolation(ValueDecl *requirement,
   // Determine the isolation of the requirement itself.
   auto requirementIsolation = getActorIsolation(requirement);
   if (requirementIsolation.requiresSubstitution()) {
-    auto substitutingType = DC->mapTypeIntoContext(Conformance->getType());
     auto subs = SubstitutionMap::getProtocolSubstitutions(
-        Proto, substitutingType, ProtocolConformanceRef(Conformance));
+        ProtocolConformanceRef(Conformance));
     requirementIsolation = requirementIsolation.subst(subs);
   }
 
@@ -3410,7 +3416,8 @@ ConformanceChecker::checkActorIsolation(ValueDecl *requirement,
   case ActorReferenceResult::EntersActor: {
     // If the conformance itself is isolated to the same isolation domain as
     // the witness, treat this as being in the same concurrency domain.
-    auto conformanceIsolation = Conformance->getIsolation();
+    auto conformanceIsolation =
+        getConformanceIsolationForIsolatedWitness(Conformance);
     if (conformanceIsolation.isGlobalActor() &&
         refResult.isolation == conformanceIsolation) {
       sameConcurrencyDomain = true;
@@ -3562,7 +3569,7 @@ ConformanceChecker::checkActorIsolation(ValueDecl *requirement,
     isLetAccessibleAnywhere(
         witness->getDeclContext()->getParentModule(),
         var, options);
-    if (options.contains(ActorReferenceResult::Flags::Preconcurrency)) {
+    if (options.contains(ActorReferenceResult::Flags::CompatibilityDowngrade)) {
       behavior = DiagnosticBehavior::Warning;
     }
   }
@@ -3673,12 +3680,11 @@ static void diagnoseWitnessFixAccessLevel(DiagnosticEngine &diags,
   // move it to another extension where the required level is possible;
   // otherwise, we simply mark decl as the required level.
   if (shouldMoveToAnotherExtension) {
-    diags.diagnose(decl, diag::witness_move_to_another_extension,
-                   decl->getDescriptiveKind(), requiredAccess);
+    diags.diagnose(decl, diag::witness_move_to_another_extension, decl,
+                   requiredAccess);
   } else {
-    auto fixItDiag = diags.diagnose(decl, diag::witness_fix_access,
-                                    decl->getDescriptiveKind(),
-                                    requiredAccess);
+    auto fixItDiag =
+        diags.diagnose(decl, diag::witness_fix_access, decl, requiredAccess);
     fixItAccess(fixItDiag, decl, requiredAccess, isForSetter,
                 shouldUseDefaultAccess);
   }
@@ -3706,8 +3712,12 @@ static Type getTupleConformanceTypeWitness(DeclContext *dc,
 
 bool swift::
 printRequirementStub(ValueDecl *Requirement, DeclContext *Adopter,
-                     Type AdopterTy, SourceLoc TypeLoc, raw_ostream &OS) {
-  if (isa<ConstructorDecl>(Requirement)) {
+                     Type AdopterTy, SourceLoc TypeLoc, raw_ostream &OS,
+                     bool withExplicitObjCAttr) {
+  // We sometimes use this for @implementation extensions too.
+  bool forProtocol = isa<ProtocolDecl>(Requirement->getDeclContext());
+
+  if (isa<ConstructorDecl>(Requirement) && forProtocol) {
     if (auto CD = Adopter->getSelfClassDecl()) {
       if (!CD->isSemanticallyFinal() && isa<ExtensionDecl>(Adopter)) {
         // In this case, user should mark class as 'final' or define
@@ -3733,15 +3743,35 @@ printRequirementStub(ValueDecl *Requirement, DeclContext *Adopter,
   ExtraIndentStreamPrinter Printer(OS, StubIndent);
   Printer.printNewline();
 
+  PrintOptions Options = PrintOptions::printForDiagnostics(
+      AccessLevel::Private, Ctx.TypeCheckerOpts.PrintFullConvention);
+  Options.PrintDocumentationComments = false;
+  Options.PrintAccess = false;
+  Options.SkipAttributes = true;
+  Options.FunctionDefinitions = true;
+  Options.PrintAccessorBodiesInProtocols = true;
+  Options.PrintExplicitAccessorParameters = false;
+  Options.FullyQualifiedTypesIfAmbiguous = true;
+
+  if (withExplicitObjCAttr) {
+    if (auto runtimeName = Requirement->getObjCRuntimeName()) {
+      llvm::SmallString<32> scratch;
+      Printer.printAttrName("@objc");
+      Printer << "(" << runtimeName->getString(scratch) << ")";
+      Printer.printNewline();
+      Options.ExcludeAttrList.push_back(DeclAttrKind::ObjC);
+    }
+  }
+
   AccessLevel Access =
     std::min(
       /* Access of the context */
       Adopter->getSelfNominalTypeDecl()->getFormalAccess(),
       /* Access of the protocol */
-      Requirement->getDeclContext()->getSelfProtocolDecl()->
-        getFormalAccess());
-  if (Access == AccessLevel::Public)
-    Printer << "public ";
+      Requirement->getDeclContext()->getSelfNominalTypeDecl()
+                      ->getFormalAccess());
+  if (Access > AccessLevel::Internal)
+    Printer.printKeyword(getAccessLevelSpelling(Access), Options, " ");
 
   if (auto MissingTypeWitness = dyn_cast<AssociatedTypeDecl>(Requirement)) {
     Printer << "typealias " << MissingTypeWitness->getName() << " = ";
@@ -3755,7 +3785,7 @@ printRequirementStub(ValueDecl *Requirement, DeclContext *Adopter,
 
     Printer << "\n";
   } else {
-    if (isa<ConstructorDecl>(Requirement)) {
+    if (isa<ConstructorDecl>(Requirement) && forProtocol) {
       if (auto CD = Adopter->getSelfClassDecl()) {
         if (!CD->isFinal()) {
           Printer << "required ";
@@ -3765,15 +3795,6 @@ printRequirementStub(ValueDecl *Requirement, DeclContext *Adopter,
       }
     }
 
-    PrintOptions Options = PrintOptions::printForDiagnostics(
-        AccessLevel::Private, Ctx.TypeCheckerOpts.PrintFullConvention);
-    Options.PrintDocumentationComments = false;
-    Options.PrintAccess = false;
-    Options.SkipAttributes = true;
-    Options.FunctionDefinitions = true;
-    Options.PrintAccessorBodiesInProtocols = true;
-    Options.FullyQualifiedTypesIfAmbiguous = true;
-
     bool AdopterIsClass = Adopter->getSelfClassDecl() != nullptr;
     // Skip 'mutating' only inside classes: mutating methods usually
     // don't have a sensible non-mutating implementation.
@@ -3799,9 +3820,12 @@ printRequirementStub(ValueDecl *Requirement, DeclContext *Adopter,
     };
     Options.setBaseType(AdopterTy);
     Options.CurrentModule = Adopter->getParentModule();
-    if (isa<NominalTypeDecl>(Adopter)) {
-      // Create a variable declaration instead of a computed property in
-      // nominal types...
+
+    // Can the conforming declaration declare a stored property?
+    auto ImplementedAdopter = Adopter->getImplementedObjCContext();
+    if (isa<NominalTypeDecl>(ImplementedAdopter) &&
+          (!isa<EnumDecl>(ImplementedAdopter) || Requirement->isStatic())) {
+      // Create a variable declaration instead of a computed property...
       Options.PrintPropertyAccessors = false;
 
       // ...but a non-mutating setter requirement will force us into a
@@ -3812,6 +3836,11 @@ printRequirementStub(ValueDecl *Requirement, DeclContext *Adopter,
           if (const auto Set = VD->getOpaqueAccessor(AccessorKind::Set))
             if (Set->getAttrs().hasAttribute<NonMutatingAttr>())
               Options.PrintPropertyAccessors = true;
+
+      // If we're not printing the accessors, make them affect the introducer
+      // instead.
+      Options.InferPropertyIntroducerFromAccessors =
+          !Options.PrintPropertyAccessors;
     }
     Requirement->print(Printer, Options);
     Printer << "\n";
@@ -3849,11 +3878,19 @@ filterProtocolRequirements(
     return Filtered;
   }
 
-  const auto getProtocolSubstitutionMap = [&](ValueDecl *Req) {
-    auto *const PD = cast<ProtocolDecl>(Req->getDeclContext());
-    auto Conformance = lookupConformance(Adoptee, PD);
-    return SubstitutionMap::getProtocolSubstitutions(
-        PD, Adoptee, Conformance);
+  const auto getProtocolSubstitutionMap = [&](ValueDecl *req) {
+    ASSERT(isa<ProtocolDecl>(req->getDeclContext()));
+    auto genericSig = req->getInnermostDeclContext()
+        ->getGenericSignatureOfContext();
+    SmallVector<Type, 2> args;
+    for (auto paramTy : genericSig.getGenericParams()) {
+      if (args.empty())
+        args.push_back(Adoptee);
+      else
+        args.push_back(paramTy);
+    }
+    return SubstitutionMap::get(genericSig, args,
+                                LookUpConformanceInModule());
   };
 
   llvm::SmallDenseMap<DeclName, llvm::SmallVector<ValueDecl *, 2>, 4>
@@ -3869,11 +3906,11 @@ filterProtocolRequirements(
     auto OverloadTy = Req->getOverloadSignatureType();
     if (OverloadTy) {
       auto Subs = getProtocolSubstitutionMap(Req);
-      // FIXME: This is wrong if the overload has its own generic parameters
-      if (auto GenericFnTy = dyn_cast<GenericFunctionType>(OverloadTy))
+      if (auto GenericFnTy = dyn_cast<GenericFunctionType>(OverloadTy)) {
         OverloadTy = GenericFnTy.substGenericArgs(Subs);
-      else
+      } else {
         OverloadTy = OverloadTy.subst(Subs)->getCanonicalType();
+      }
     }
     if (llvm::any_of(DeclsByName[Req->getName()], [&](ValueDecl *OtherReq) {
           auto OtherOverloadTy = OtherReq->getOverloadSignatureType();
@@ -3993,16 +4030,14 @@ static void diagnoseProtocolStubFixit(
 
     // Issue diagnostics for witness types.
     if (auto MissingTypeWitness = dyn_cast<AssociatedTypeDecl>(VD)) {
-      std::optional<InFlightDiagnostic> diag;
       if (isa<BuiltinTupleDecl>(DC->getSelfNominalTypeDecl())) {
         auto expectedTy = getTupleConformanceTypeWitness(DC, MissingTypeWitness);
-        diag.emplace(Diags.diagnose(MissingTypeWitness, diag::no_witnesses_type_tuple,
-                                    MissingTypeWitness, expectedTy));
+        Diags.diagnose(MissingTypeWitness, diag::no_witnesses_type_tuple,
+                       MissingTypeWitness, expectedTy);
       } else {
-        diag.emplace(Diags.diagnose(MissingTypeWitness, diag::no_witnesses_type,
-                                    MissingTypeWitness));
+        Diags.diagnose(MissingTypeWitness, diag::no_witnesses_type,
+                       MissingTypeWitness);
       }
-      diag.value().flush();
       continue;
     }
 
@@ -4152,7 +4187,6 @@ void ConformanceChecker::checkNonFinalClassWitness(ValueDecl *requirement,
             // If the main diagnostic is emitted on the conformance, we want to
             // attach the fix-it to the note that shows where the initializer is
             // defined.
-            fixItDiag.value().flush();
             fixItDiag.emplace(diags.diagnose(ctor, diag::decl_declared_here,
                                              ctor));
           }
@@ -4190,8 +4224,10 @@ void ConformanceChecker::checkNonFinalClassWitness(ValueDecl *requirement,
     // by holding onto Self accordingly.
     if (witness->getDeclContext()->getSelfClassDecl()) {
       const bool hasDynamicSelfResult = [&] {
-        if (auto func = dyn_cast<AbstractFunctionDecl>(witness)) {
-          return func->hasDynamicSelfResult();
+        if (isa<ConstructorDecl>(witness)) {
+          return true;
+        } else if (auto func = dyn_cast<FuncDecl>(witness)) {
+          return func->getResultInterfaceType()->hasDynamicSelfType();
         } else if (auto var = dyn_cast<VarDecl>(witness)) {
           return var->getInterfaceType()->hasDynamicSelfType();
         }
@@ -4331,14 +4367,12 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
             if (diagLoc == witness->getLoc()) {
               fixDeclarationName(diag, witness, requirement->getName());
             } else {
-              diag.flush();
               diags.diagnose(witness, diag::decl_declared_here, witness);
             }
           }
 
-          diags.diagnose(requirement, diag::kind_declname_declared_here,
-                         DescriptiveDeclKind::Requirement,
-                         requirement->getName());
+          diags.diagnose(requirement, diag::requirement_declared_here,
+                         requirement);
         });
     }
     if (best.Kind == MatchKind::RequiresNonSendable) {
@@ -4376,12 +4410,11 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
 
     auto check = checkWitness(requirement, best);
 
-    switch (check.Kind) {
+    switch (check.getKind()) {
     case CheckKind::Success:
       break;
 
-    case CheckKind::Access:
-    case CheckKind::AccessOfSetter: {
+    case CheckKind::Access: {
       // Swift 4.2 relaxed some rules for protocol witness matching.
       //
       // This meant that it was possible for an optional protocol requirement
@@ -4402,7 +4435,7 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
       getASTContext().addDelayedConformanceDiag(Conformance, false,
         [DC, witness, check, requirement](
           NormalProtocolConformance *conformance) {
-        auto requiredAccessScope = check.RequiredAccessScope;
+        auto requiredAccessScope = check.getRequiredAccessScope();
         AccessLevel requiredAccess =
           requiredAccessScope.requiredAccessForDiagnostics();
         auto proto = conformance->getProtocol();
@@ -4412,7 +4445,7 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
         auto diagKind = protoForcesAccess
                           ? diag::witness_not_accessible_proto
                           : diag::witness_not_accessible_type;
-        bool isSetter = (check.Kind == CheckKind::AccessOfSetter);
+        bool isSetter = check.isForSetterAccess();
 
         auto &diags = DC->getASTContext().Diags;
         diags.diagnose(getLocForDiagnosingWitness(conformance, witness),
@@ -4437,25 +4470,57 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
       break;
 
     case CheckKind::Availability: {
-      getASTContext().addDelayedConformanceDiag(Conformance, false,
-        [witness, requirement, check](
-            NormalProtocolConformance *conformance) {
-          // FIXME: The problem may not be the OS version.
-          ASTContext &ctx = witness->getASTContext();
-          auto &diags = ctx.Diags;
-          SourceLoc diagLoc = getLocForDiagnosingWitness(conformance, witness);
-          diags.diagnose(diagLoc, diag::availability_protocol_requires_version,
-                         conformance->getProtocol(), witness,
-                         ctx.getTargetAvailabilityDomain(),
-                         check.RequiredAvailability);
-          emitDeclaredHereIfNeeded(diags, diagLoc, witness);
-          diags.diagnose(requirement,
-                         diag::availability_protocol_requirement_here);
-        });
+      if (check.isLessAvailable()) {
+        getASTContext().addDelayedConformanceDiag(
+            Conformance, false,
+            [witness, requirement,
+             check](NormalProtocolConformance *conformance) {
+              ASTContext &ctx = witness->getASTContext();
+              auto &diags = ctx.Diags;
+              auto diagLoc = getLocForDiagnosingWitness(conformance, witness);
+              auto attr = check.getAvailabilityConstraint().getAttr();
+              auto domain = attr.getDomain();
+              auto requiredRange =
+                  check.getRequiredAvailabilityContext().getAvailabilityRange(
+                      domain, ctx);
+              if (requiredRange) {
+                diags.diagnose(
+                    diagLoc, diag::availability_protocol_requires_version,
+                    conformance->getProtocol(), witness,
+                    domain.isPlatform() ? ctx.getTargetAvailabilityDomain()
+                                        : domain,
+                    *requiredRange);
+              } else {
+                diags.diagnose(
+                    diagLoc,
+                    diag::availability_protocol_requirement_only_available_in,
+                    conformance->getProtocol(), witness, domain);
+              }
+              emitDeclaredHereIfNeeded(diags, diagLoc, witness);
+              diags.diagnose(requirement,
+                             diag::availability_protocol_requirement_here);
+            });
+      } else {
+        getASTContext().addDelayedConformanceDiag(
+            Conformance, true,
+            [witness, requirement,
+             check](NormalProtocolConformance *conformance) {
+              auto &diags = witness->getASTContext().Diags;
+              auto diagLoc = getLocForDiagnosingWitness(conformance, witness);
+              auto attr = check.getAvailabilityConstraint().getAttr();
+              EncodedDiagnosticMessage EncodedMessage(attr.getMessage());
+              diags.diagnose(diagLoc, diag::witness_unavailable, witness,
+                             conformance->getProtocol(),
+                             EncodedMessage.Message);
+              emitDeclaredHereIfNeeded(diags, diagLoc, witness);
+              diags.diagnose(requirement, diag::requirement_declared_here,
+                             requirement);
+            });
+      }
       break;
     }
 
-    case CheckKind::Unavailable: {
+    case CheckKind::RequirementUnavailable: {
       diagnoseOverrideOfUnavailableDecl(
           witness, requirement, requirement->getUnavailableAttr().value());
       break;
@@ -4482,14 +4547,12 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
             if (diagLoc == witness->getLoc()) {
               addOptionalityFixIts(adjustments, ctx, witness, diag);
             } else {
-              diag.flush();
               diags.diagnose(witness, diag::decl_declared_here, witness);
             }
           }
 
-          diags.diagnose(requirement, diag::kind_declname_declared_here,
-                         DescriptiveDeclKind::Requirement,
-                         requirement->getName());
+          diags.diagnose(requirement, diag::requirement_declared_here,
+                         requirement);
       });
       break;
     }
@@ -4509,22 +4572,6 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
 
       break;
 
-    case CheckKind::WitnessUnavailable:
-      getASTContext().addDelayedConformanceDiag(Conformance, true,
-        [witness, requirement](NormalProtocolConformance *conformance) {
-          auto &diags = witness->getASTContext().Diags;
-          SourceLoc diagLoc = getLocForDiagnosingWitness(conformance, witness);
-          auto attr = witness->getUnavailableAttr();
-          EncodedDiagnosticMessage EncodedMessage(attr->getMessage());
-          diags.diagnose(diagLoc, diag::witness_unavailable, witness,
-                         conformance->getProtocol(), EncodedMessage.Message);
-          emitDeclaredHereIfNeeded(diags, diagLoc, witness);
-          diags.diagnose(requirement, diag::kind_declname_declared_here,
-                         DescriptiveDeclKind::Requirement,
-                         requirement->getName());
-        });
-      break;
-
       case CheckKind::DefaultWitnessDeprecated:
         getASTContext().addDelayedConformanceDiag(
           Conformance, /*isError=*/false,
@@ -4538,9 +4585,8 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
                            witness, conformance->getProtocol()->getName(),
                            EncodedMessage.Message);
             emitDeclaredHereIfNeeded(diags, diagLoc, witness);
-            diags.diagnose(requirement, diag::kind_declname_declared_here,
-                           DescriptiveDeclKind::Requirement,
-                           requirement->getName());
+            diags.diagnose(requirement, diag::requirement_declared_here,
+                           requirement);
           });
         break;
     }
@@ -4697,9 +4743,8 @@ ResolveWitnessResult ConformanceChecker::resolveWitnessViaDerivation(
 
   // Find the declaration that derives the protocol conformance.
   NominalTypeDecl *derivingTypeDecl = nullptr;
-  auto *nominal = DC->getSelfNominalTypeDecl();
-  if (DerivedConformance::derivesProtocolConformance(DC, nominal, Proto))
-    derivingTypeDecl = nominal;
+  if (DerivedConformance::derivesProtocolConformance(Conformance))
+    derivingTypeDecl = DC->getSelfNominalTypeDecl();
 
   if (!derivingTypeDecl) {
     return ResolveWitnessResult::Missing;
@@ -4782,16 +4827,35 @@ void ConformanceChecker::resolveSingleWitness(ValueDecl *requirement) {
   if (!requirement->isProtocolRequirement())
     return;
 
+  auto &evaluator = getASTContext().evaluator;
+
   // Resolve the type witnesses for all associated types referenced by
   // the requirement. If any are erroneous, don't bother resolving the
   // witness.
-  auto referenced = evaluateOrDefault(getASTContext().evaluator,
+  auto referenced = evaluateOrDefault(evaluator,
                                       ReferencedAssociatedTypesRequest{requirement},
                                       TinyPtrVector<AssociatedTypeDecl *>());
   for (auto assocType : referenced) {
+    // There's a weird cycle break here. If we're in the middle of resolving
+    // type witnesses, we return from here without recording a value witness.
+    // This is handled by not caching the result, and the conformance checker
+    // will then attempt to resolve the value witness later.
+    if (evaluator.hasActiveRequest(TypeWitnessRequest{Conformance, assocType})) {
+      return;
+    }
+
+    if (!Conformance->hasTypeWitness(assocType)) {
+      if (evaluator.hasActiveRequest(ResolveTypeWitnessesRequest{Conformance})) {
+        return;
+      }
+    }
+
     auto typeWitness = Conformance->getTypeWitness(assocType);
     if (!typeWitness)
       return;
+
+    // However, if the type witness was already resolved and it has an error
+    // type, mark the conformance invalid and give up.
     if (typeWitness->hasError()) {
       Conformance->setInvalid();
       return;
@@ -4947,6 +5011,9 @@ static void diagnoseConformanceIsolationErrors(
       hasIsolatedConformances = true;
     }
 
+    // Take the least-restrictive behavior.
+    behavior = behavior.merge(assocConformanceError.behavior);
+
     anyNonDistributedIssues = true;
   }
 
@@ -4975,22 +5042,22 @@ static void diagnoseConformanceIsolationErrors(
     }
 
     // Suggest isolating the conformance, if possible.
-    if (ctx.LangOpts.hasFeature(Feature::IsolatedConformances) &&
-        potentialIsolation && potentialIsolation->isGlobalActor() &&
+    if (potentialIsolation && potentialIsolation->isGlobalActor() &&
         !conformance->isIsolated()) {
       bool isMainActor = false;
-      Type globalActorIsolation = potentialIsolation->getGlobalActor();
-      if (auto nominal = globalActorIsolation->getAnyNominal())
+      Type globalActorType = potentialIsolation->getGlobalActor();
+      if (auto nominal = globalActorType->getAnyNominal())
         isMainActor = nominal->isMainActor();
 
-      ctx.Diags.diagnose(
-          conformance->getProtocolNameLoc(),
-          diag::note_isolate_conformance_to_global_actor,
-          globalActorIsolation,
-          isMainActor,
-          globalActorIsolation.getString())
-        .fixItInsert(conformance->getProtocolNameLoc(),
-                     "@" + globalActorIsolation.getString() + " ");
+      // Take permanent ownership of the string. The diagnostic may outlive this
+      // function call.
+      auto globalActorTypeStr = ctx.AllocateCopy(globalActorType.getString());
+      auto diag =
+          ctx.Diags.diagnose(conformance->getProtocolNameLoc(),
+                             diag::note_isolate_conformance_to_global_actor,
+                             globalActorType, isMainActor, globalActorTypeStr);
+      conformance->applyConformanceAttribute(diag,
+                                             "@" + globalActorTypeStr.str());
     }
 
     // If marking witnesses as 'nonisolated' could work, suggest that.
@@ -5008,10 +5075,10 @@ static void diagnoseConformanceIsolationErrors(
     // If the conformance could be @preconcurrency, suggest it.
     if (!conformance->isIsolated() && !conformance->isPreconcurrency() &&
         !hasIsolatedConformances) {
-      ctx.Diags.diagnose(
-          conformance->getProtocolNameLoc(),
-          diag::note_make_conformance_preconcurrency)
-        .fixItInsert(conformance->getProtocolNameLoc(), "@preconcurrency ");
+      auto diag =
+          ctx.Diags.diagnose(conformance->getProtocolNameLoc(),
+                             diag::note_make_conformance_preconcurrency);
+      conformance->applyConformanceAttribute(diag, "@preconcurrency");
     }
 
     // Make a note of all of the isolation problems we encountered in this
@@ -5165,62 +5232,92 @@ static void diagnoseInvariantSelfRequirement(
       .warnUntilSwiftVersion(6);
 }
 
-static bool diagnoseTypeWitnessAvailability(
-    NormalProtocolConformance *conformance, const TypeDecl *witness,
-    const AssociatedTypeDecl *assocType, const ExportContext &where) {
+static bool
+diagnoseTypeWitnessAvailability(NormalProtocolConformance *conformance,
+                                const TypeDecl *witness,
+                                const AssociatedTypeDecl *assocType) {
   auto dc = conformance->getDeclContext();
   auto &ctx = dc->getASTContext();
   if (ctx.LangOpts.DisableAvailabilityChecking)
     return false;
 
+  auto requiredAvailability = AvailabilityContext::forAlwaysAvailable(ctx);
+  auto constraint =
+      checkWitnessAvailability(assocType, witness, dc, requiredAvailability);
+  if (!constraint)
+    return false;
+
+  auto attr = constraint->getAttr();
+  auto domain = attr.getDomain();
+
   // In Swift 6 and earlier type witness availability diagnostics are warnings.
-  const unsigned warnBeforeVersion = 7;
+  using namespace version;
+  const unsigned warnBeforeVersion = Version::getFutureMajorLanguageVersion();
   bool shouldError =
       ctx.LangOpts.EffectiveLanguageVersion.isVersionAtLeast(warnBeforeVersion);
 
-  auto constraint =
-      getAvailabilityConstraintsForDecl(witness, where.getAvailability())
-          .getPrimaryConstraint();
-  if (constraint && constraint->isUnavailable()) {
-    auto attr = constraint->getAttr();
+  switch (domain.getKind()) {
+  case AvailabilityDomain::Kind::Universal:
+  case AvailabilityDomain::Kind::SwiftLanguageMode:
+  case AvailabilityDomain::Kind::PackageDescription:
+  case AvailabilityDomain::Kind::Platform:
+    break;
+  case AvailabilityDomain::Kind::SwiftRuntime:
+  case AvailabilityDomain::Kind::Embedded:
+  case AvailabilityDomain::Kind::Custom:
+    shouldError = true;
+    break;
+  }
+
+  if (constraint->isUnavailable()) {
     ctx.addDelayedConformanceDiag(
         conformance, shouldError,
-        [witness, assocType, attr](NormalProtocolConformance *conformance) {
+        [witness, assocType, attr,
+         shouldError](NormalProtocolConformance *conformance) {
           SourceLoc loc = getLocForDiagnosingWitness(conformance, witness);
           EncodedDiagnosticMessage encodedMessage(attr.getMessage());
           auto &ctx = conformance->getDeclContext()->getASTContext();
           ctx.Diags
               .diagnose(loc, diag::witness_unavailable, witness,
                         conformance->getProtocol(), encodedMessage.Message)
-              .warnUntilSwiftVersion(warnBeforeVersion);
+              .warnUntilSwiftVersionIf(!shouldError, warnBeforeVersion);
 
           emitDeclaredHereIfNeeded(ctx.Diags, loc, witness);
-          ctx.Diags.diagnose(assocType, diag::kind_declname_declared_here,
-                             DescriptiveDeclKind::Requirement,
-                             assocType->getName());
+          ctx.Diags.diagnose(assocType, diag::requirement_declared_here,
+                             assocType);
         });
+    return true;
   }
 
-  auto requiredRange = AvailabilityRange::alwaysAvailable();
-  if (!TypeChecker::isAvailabilitySafeForConformance(
-          conformance->getProtocol(), assocType, witness, dc, requiredRange)) {
-    ctx.addDelayedConformanceDiag(
-        conformance, shouldError,
-        [witness, requiredRange](NormalProtocolConformance *conformance) {
-          SourceLoc loc = getLocForDiagnosingWitness(conformance, witness);
-          auto &ctx = conformance->getDeclContext()->getASTContext();
+  auto requiredRange = requiredAvailability.getAvailabilityRange(domain, ctx);
+
+  ctx.addDelayedConformanceDiag(
+      conformance, shouldError,
+      [witness, attr, requiredRange,
+       shouldError](NormalProtocolConformance *conformance) {
+        SourceLoc loc = getLocForDiagnosingWitness(conformance, witness);
+        auto &ctx = conformance->getDeclContext()->getASTContext();
+        auto domain = attr.getDomain();
+        if (requiredRange) {
           ctx.Diags
               .diagnose(loc, diag::availability_protocol_requires_version,
                         conformance->getProtocol(), witness,
-                        ctx.getTargetAvailabilityDomain(), requiredRange)
-              .warnUntilSwiftVersion(warnBeforeVersion);
-
-          emitDeclaredHereIfNeeded(ctx.Diags, loc, witness);
-        });
-    return true;
-  }
+                        domain.isPlatform() ? ctx.getTargetAvailabilityDomain()
+                                            : domain,
+                        *requiredRange)
+              .warnUntilSwiftVersionIf(!shouldError, warnBeforeVersion);
+        } else {
+          ctx.Diags
+              .diagnose(
+                  loc,
+                  diag::availability_protocol_requirement_only_available_in,
+                  conformance->getProtocol(), witness, domain)
+              .warnUntilSwiftVersionIf(!shouldError, warnBeforeVersion);
+        }
 
-  return false;
+        emitDeclaredHereIfNeeded(ctx.Diags, loc, witness);
+      });
+  return true;
 }
 
 /// Check whether the type witnesses satisfy the protocol's requirement
@@ -5237,8 +5334,7 @@ static void ensureRequirementsAreSatisfied(ASTContext &ctx,
   if (auto *genericEnv = conformance->getGenericEnvironment()) {
     typeInContext = genericEnv->mapTypeIntoContext(typeInContext);
     conformanceInContext =
-      conformanceInContext.subst(conformance->getType(),
-                                 genericEnv->getForwardingSubstitutionMap());
+      conformanceInContext.subst(genericEnv->getForwardingSubstitutionMap());
   }
   auto substitutions = SubstitutionMap::getProtocolSubstitutions(
       proto, typeInContext, conformanceInContext);
@@ -5354,7 +5450,7 @@ static void ensureRequirementsAreSatisfied(ASTContext &ctx,
 
     // The type witness must be as available as the associated type.
     if (auto witness = type->getAnyNominal())
-      diagnoseTypeWitnessAvailability(conformance, witness, assocType, where);
+      diagnoseTypeWitnessAvailability(conformance, witness, assocType);
 
     // Make sure any associated type witnesses don't make reference to a
     // type we can't emit metadata for, or we're going to have trouble at
@@ -5405,9 +5501,19 @@ static void ensureRequirementsAreSatisfied(ASTContext &ctx,
             // If the isolation doesn't match, record an error.
             if (!outerIsolation.isGlobalActor() ||
                 outerIsolation != innerIsolation) {
+              DiagnosticBehavior behavior = DiagnosticBehavior::Unspecified;
+              // If we're working with requirements imported from Clang, or with
+              // global actor isolation in general, use the default diagnostic
+              // behavior based on the conformance context.
+              if (proto->hasClangNode() ||
+                  outerIsolation.isGlobalActor() ||
+                  innerIsolation.isGlobalActor())
+                behavior = SendableCheckContext(dc).defaultDiagnosticBehavior();
+
               ctx.getGlobalCache().conformanceIsolationErrors[conformance]
                 .push_back(
-                  AssociatedConformanceIsolationError{isolatedConformance});
+                  AssociatedConformanceIsolationError{
+                    isolatedConformance, behavior});
               return true;
             }
 
@@ -5534,9 +5640,8 @@ void ConformanceChecker::resolveValueWitnesses() {
               // If the main diagnostic is emitted on the conformance, we want
               // to attach the fix-it to the note that shows where the
               // witness is defined.
-              fixItDiag.value().flush();
-              fixItDiag.emplace(witness->diagnose(
-                  diag::make_decl_objc, witness->getDescriptiveKind()));
+              fixItDiag.emplace(
+                  witness->diagnose(diag::make_decl_objc, witness));
             }
             if (!witness->canInferObjCFromRequirement(requirement)) {
               fixDeclarationObjCName(
@@ -5554,9 +5659,8 @@ void ConformanceChecker::resolveValueWitnesses() {
               // If the main diagnostic is emitted on the conformance, we want
               // to attach the fix-it to the note that shows where the
               // witness is defined.
-              fixItDiag.value().flush();
-              fixItDiag.emplace(witness->diagnose(
-                  diag::make_decl_objc, witness->getDescriptiveKind()));
+              fixItDiag.emplace(
+                  witness->diagnose(diag::make_decl_objc, witness));
             }
             if (!witness->canInferObjCFromRequirement(requirement)) {
               fixDeclarationObjCName(
@@ -5574,9 +5678,8 @@ void ConformanceChecker::resolveValueWitnesses() {
               // If the main diagnostic is emitted on the conformance, we want
               // to attach the fix-it to the note that shows where the
               // witness is defined.
-              fixItDiag.value().flush();
-              fixItDiag.emplace(witness->diagnose(
-                  diag::make_decl_objc, witness->getDescriptiveKind()));
+              fixItDiag.emplace(
+                  witness->diagnose(diag::make_decl_objc, witness));
             }
             fixItDiag->fixItInsert(witness->getAttributeInsertionLoc(false),
                                    "@objc ");
@@ -5590,9 +5693,7 @@ void ConformanceChecker::resolveValueWitnesses() {
                              "@nonobjc ");
           }
 
-          requirement->diagnose(diag::kind_declname_declared_here,
-                                DescriptiveDeclKind::Requirement,
-                                requirement->getName());
+          requirement->diagnose(diag::requirement_declared_here, requirement);
 
           Conformance->setInvalid();
           return;
@@ -6278,8 +6379,7 @@ static void diagnosePotentialWitness(NormalProtocolConformance *conformance,
         .fixItInsert(witness->getAttributeInsertionLoc(false), "@nonobjc ");
   }
 
-  req->diagnose(diag::kind_declname_declared_here,
-                DescriptiveDeclKind::Requirement, req->getName());
+  req->diagnose(diag::requirement_declared_here, req);
 }
 
 /// Whether the given protocol is "NSCoding".
@@ -6390,12 +6490,11 @@ static void inferStaticInitializeObjCMetadata(ClassDecl *classDecl) {
   // only statically initialize the Objective-C metadata when running on
   // a new-enough OS.
   if (classDecl->getParentSourceFile()) {
-    AvailabilityRange safeRangeUnderApprox{
-        AvailabilityInference::availableRange(classDecl)};
-    AvailabilityRange runningOSOverApprox =
+    auto classAvailability = AvailabilityContext::forDeclSignature(classDecl);
+    AvailabilityRange deploymentTarget =
         AvailabilityRange::forDeploymentTarget(ctx);
 
-    if (!runningOSOverApprox.isContainedIn(safeRangeUnderApprox))
+    if (!deploymentTarget.isContainedIn(classAvailability.getPlatformRange()))
       return;
   }
 
@@ -6646,7 +6745,7 @@ void TypeChecker::checkConformancesInContext(IterableDeclContext *idc) {
   if (!hasDeprecatedUnsafeSendable && SendableConformance) {
     SendableCheck check = SendableCheck::Explicit;
     if (sendableConformancePreconcurrency)
-      check = SendableCheck::ImpliedByStandardProtocol;
+      check = SendableCheck::ImpliedByPreconcurrencyProtocol;
     else if (SendableConformance->getSourceKind() ==
                  ConformanceEntryKind::Synthesized)
       check = SendableCheck::Implicit;
@@ -6663,6 +6762,50 @@ void TypeChecker::checkConformancesInContext(IterableDeclContext *idc) {
     }
   }
 
+  // If we are migrating to InferIsolatedConformances, and the
+  // nominal type is global-actor-isolated, look for conformances
+  // that are nonisolated but were not explicitly marked as such.
+  // These conformances will need to be marked 'nonisolated' to
+  // retain their current behavior.
+  if (Context.LangOpts
+          .getFeatureState(Feature::InferIsolatedConformances)
+            .isEnabledForMigration() &&
+      getActorIsolation(const_cast<NominalTypeDecl *>(nominal))
+          .isGlobalActor()) {
+    for (auto conformance : conformances) {
+      auto normal = dyn_cast<NormalProtocolConformance>(conformance);
+      if (!normal)
+        continue;
+
+      // Explicit nonisolated and @preconcurrency suppress this.
+      auto options = normal->getOptions();
+      if (options.contains(ProtocolConformanceFlags::Nonisolated) ||
+          options.contains(ProtocolConformanceFlags::Preconcurrency))
+        continue;
+
+      // Only consider conformances that were explicitly written in the source.
+      if (normal->getSourceKind() != ConformanceEntryKind::Explicit)
+        continue;
+
+      // Only consider conformances to non-marker, nonisolated protocols.
+      auto proto = normal->getProtocol();
+      if (proto->isMarkerProtocol() || getActorIsolation(proto).isActorIsolated())
+        continue;
+
+      // Only nonisolated conformances can be affected.
+      if (!conformance->getIsolation().isNonisolated())
+        continue;
+
+      auto nameLoc = normal->getProtocolNameLoc();
+      if (nameLoc.isValid()) {
+        auto diag = Context.Diags.diagnose(
+            nameLoc, diag::isolated_conformance_will_become_nonisolated,
+            nominal, proto);
+        normal->applyConformanceAttribute(diag, "nonisolated");
+      }
+    }
+  }
+
   if (Context.TypeCheckerOpts.DebugGenericSignatures &&
       !conformances.empty()) {
     // Now that they're filled out, print out information about the conformances
@@ -6786,16 +6929,22 @@ void TypeChecker::checkConformancesInContext(IterableDeclContext *idc) {
     // is implied for enums which already declare a raw type.
     if (auto enumDecl = dyn_cast<EnumDecl>(existingDecl)) {
       if (diag.Protocol->isSpecificProtocol(
-              KnownProtocolKind::RawRepresentable) &&
-          DerivedConformance::derivesProtocolConformance(dc, enumDecl,
-                                                         diag.Protocol) &&
-          enumDecl->hasRawType() &&
-          enumDecl->getInherited().getStartLoc().isValid()) {
-        auto inheritedLoc = enumDecl->getInherited().getStartLoc();
-        Context.Diags.diagnose(
-            inheritedLoc, diag::enum_declares_rawrep_with_raw_type,
-            dc->getDeclaredInterfaceType(), enumDecl->getRawType());
-        continue;
+              KnownProtocolKind::RawRepresentable)) {
+        auto conformance = lookupConformance(
+            enumDecl->getDeclaredInterfaceType(), diag.Protocol);
+        if (!conformance.isConcrete())
+          continue;
+
+        if (DerivedConformance::derivesProtocolConformance(
+              conformance.getConcrete()->getRootNormalConformance()) &&
+            enumDecl->hasRawType() &&
+            enumDecl->getInherited().getStartLoc().isValid()) {
+          auto inheritedLoc = enumDecl->getInherited().getStartLoc();
+          Context.Diags.diagnose(
+              inheritedLoc, diag::enum_declares_rawrep_with_raw_type,
+              dc->getDeclaredInterfaceType(), enumDecl->getRawType());
+          continue;
+        }
       }
     }
 
@@ -6953,6 +7102,8 @@ swift::findWitnessedObjCRequirements(const ValueDecl *witness,
     case AccessorKind::Modify:
     case AccessorKind::Modify2:
     case AccessorKind::Init:
+    case AccessorKind::Borrow:
+    case AccessorKind::Mutate:
       // These accessors are never exposed to Objective-C.
       return result;
     case AccessorKind::DidSet:
@@ -7128,7 +7279,7 @@ DefaultWitnessChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
     // Perform the same checks as conformance witness matching, but silently
     // ignore the candidate instead of diagnosing anything.
     auto check = checkWitness(requirement, best);
-    if (check.Kind != CheckKind::Success)
+    if (check.getKind() != CheckKind::Success)
       return ResolveWitnessResult::ExplicitFailed;
 
     // Record the match.
@@ -7201,7 +7352,8 @@ void TypeChecker::inferDefaultWitnesses(ProtocolDecl *proto) {
         RequirementEnvironment reqEnv(proto, reqSig, proto, nullptr, nullptr);
         auto match =
             RequirementMatch(asd, MatchKind::ExactMatch, asdTy, reqEnv);
-        match.WitnessSubstitutions = reqEnv.getRequirementToWitnessThunkSubs();
+        match.WitnessSubstitutions = reqEnv.getRequirementToWitnessThunkSubs()
+                                           .mapReplacementTypesOutOfContext();
         checker.recordWitness(asd, match);
       }
     }
diff --git a/lib/Sema/TypeCheckProtocol.h b/lib/Sema/TypeCheckProtocol.h
index 0960773241fc9..59312da8ba9ec 100644
--- a/lib/Sema/TypeCheckProtocol.h
+++ b/lib/Sema/TypeCheckProtocol.h
@@ -53,7 +53,7 @@ SmallVector<ValueDecl *, 4> lookupValueWitnesses(DeclContext *DC,
                                                  ValueDecl *req,
                                                  bool *ignoringNames);
 
-struct RequirementCheck;
+class RequirementCheck;
 
 class WitnessChecker {
 public:
@@ -88,10 +88,6 @@ class WitnessChecker {
                        unsigned &bestIdx,
                        bool &doNotDiagnoseMatches);
 
-  bool checkWitnessAvailability(ValueDecl *requirement,
-                                ValueDecl *witness,
-                                AvailabilityRange *requirementInfo);
-
   RequirementCheck checkWitness(ValueDecl *requirement,
                                 const RequirementMatch &match);
 };
diff --git a/lib/Sema/TypeCheckRequestFunctions.cpp b/lib/Sema/TypeCheckRequestFunctions.cpp
index 9ce0d2558e506..ec0ecf94003c2 100644
--- a/lib/Sema/TypeCheckRequestFunctions.cpp
+++ b/lib/Sema/TypeCheckRequestFunctions.cpp
@@ -49,7 +49,7 @@ InheritedTypeResult InheritedTypeRequest::evaluate(
       }
     }
   } else {
-    dc = (DeclContext *)decl.get<const ExtensionDecl *>();
+    dc = (DeclContext *)cast<const ExtensionDecl *>(decl);
     context = TypeResolverContext::Inherited;
   }
 
@@ -369,7 +369,6 @@ static Type inferResultBuilderType(ValueDecl *decl)  {
         // into context when applying the result builder to the
         // function body in the constraint system.
         auto subs = SubstitutionMap::getProtocolSubstitutions(
-            protocol, dc->getSelfInterfaceType(),
             ProtocolConformanceRef(conformance));
         Type subResultBuilderType = resultBuilderType.subst(subs);
 
@@ -487,12 +486,12 @@ Type ResultBuilderTypeRequest::evaluate(Evaluator &evaluator,
   return type->mapTypeOutOfContext();
 }
 
-Type GenericTypeParamDeclGetValueTypeRequest::evaluate(Evaluator &evaluator,
-                                             GenericTypeParamDecl *decl) const {
-  if (!decl->isValue())
-    return Type();
+Type GenericTypeParamDeclGetValueTypeRequest::evaluate(
+    Evaluator &evaluator, const GenericTypeParamDecl *decl) const {
+  ASSERT(decl->isValue());
 
-  if (decl->getInherited().size() == 0) {
+  auto inherited = decl->getInherited();
+  if (inherited.empty()) {
     decl->diagnose(diag::missing_value_generic_type, decl->getName());
     return Type();
   }
@@ -503,12 +502,11 @@ Type GenericTypeParamDeclGetValueTypeRequest::evaluate(Evaluator &evaluator,
   //
   // We should have 1 inherited type for 'N', 'Int', and have a 2nd generic
   // parameter called 'Bool'.
-  ASSERT(decl->getInherited().size() == 1);
+  ASSERT(inherited.size() == 1);
 
   // The value type of a generic parameter should never rely on the generic
   // signature of the generic parameter itself or any of the outside context.
-  return decl->getInherited().getResolvedType(0,
-                                              TypeResolutionStage::Structural);
+  return inherited.getResolvedType(0, TypeResolutionStage::Structural);
 }
 
 // Define request evaluation functions for each of the type checker requests.
diff --git a/lib/Sema/TypeCheckStmt.cpp b/lib/Sema/TypeCheckStmt.cpp
index eb3495302f68e..658b791e59f64 100644
--- a/lib/Sema/TypeCheckStmt.cpp
+++ b/lib/Sema/TypeCheckStmt.cpp
@@ -126,7 +126,7 @@ namespace {
       // The ASTWalker doesn't walk the case body variables, contextualize them
       // ourselves.
       if (auto *CS = dyn_cast<CaseStmt>(S)) {
-        for (auto *CaseVar : CS->getCaseBodyVariablesOrEmptyArray())
+        for (auto *CaseVar : CS->getCaseBodyVariables())
           CaseVar->setDeclContext(ParentDC);
       }
       // A few statements store DeclContexts, update them.
@@ -341,7 +341,7 @@ namespace {
 
     PreWalkResult<Stmt *> walkToStmtPre(Stmt *S) override {
       if (auto caseStmt = dyn_cast<CaseStmt>(S)) {
-        for (auto var : caseStmt->getCaseBodyVariablesOrEmptyArray())
+        for (auto var : caseStmt->getCaseBodyVariables())
           setLocalDiscriminator(var);
       }
       return Action::Continue(S);
@@ -810,6 +810,37 @@ ConcreteDeclRef TypeChecker::getReferencedDeclForHasSymbolCondition(Expr *E) {
   return ConcreteDeclRef();
 }
 
+static bool typeCheckAvailableStmtConditionElement(StmtConditionElement &elt,
+                                                   bool &isFalseable,
+                                                   DeclContext *dc) {
+  auto info = elt.getAvailability();
+  if (info->isInvalid()) {
+    isFalseable = true;
+    return false;
+  }
+
+  auto &diags = dc->getASTContext().Diags;
+  bool isConditionAlwaysTrue = false;
+
+  if (auto query = info->getAvailabilityQuery()) {
+    auto domain = query->getDomain();
+    if (query->isConstant() && domain.isPermanentlyAlwaysEnabled()) {
+      isConditionAlwaysTrue = *query->getConstantResult();
+
+      diags
+        .diagnose(elt.getStartLoc(),
+                  diag::availability_query_useless_always_true, domain,
+                  isConditionAlwaysTrue)
+        .highlight(elt.getSourceRange());
+    }
+  }
+
+  if (!isConditionAlwaysTrue)
+    isFalseable = true;
+
+  return false;
+}
+
 static bool typeCheckHasSymbolStmtConditionElement(StmtConditionElement &elt,
                                                    DeclContext *dc) {
   auto Info = elt.getHasSymbolInfo();
@@ -874,10 +905,6 @@ typeCheckPatternBindingStmtConditionElement(StmtConditionElement &elt,
   // provide type information.
   auto contextualPattern = ContextualPattern::forRawPattern(pattern, dc);
   Type patternType = TypeChecker::typeCheckPattern(contextualPattern);
-  if (patternType->hasError()) {
-    typeCheckPatternFailed();
-    return true;
-  }
 
   // If the pattern didn't get a type, it's because we ran into some
   // unknown types along the way. We'll need to check the initializer.
@@ -895,8 +922,7 @@ bool TypeChecker::typeCheckStmtConditionElement(StmtConditionElement &elt,
                                                 DeclContext *dc) {
   switch (elt.getKind()) {
   case StmtConditionElement::CK_Availability:
-    isFalsable = true;
-    return false;
+    return typeCheckAvailableStmtConditionElement(elt, isFalsable, dc);
   case StmtConditionElement::CK_HasSymbol:
     isFalsable = true;
     return typeCheckHasSymbolStmtConditionElement(elt, dc);
@@ -924,8 +950,9 @@ static bool typeCheckConditionForStatement(LabeledConditionalStmt *stmt,
         TypeChecker::typeCheckStmtConditionElement(elt, hadAnyFalsable, dc);
   }
 
-  // If the binding is not refutable, and there *is* an else, reject it as
-  // unreachable.
+  // If none of the statement's conditions can be false, diagnose.
+  // FIXME: Also diagnose if none of the statements conditions can be true.
+  // FIXME: Offer a fix-it to remove the unreachable code.
   if (!hadAnyFalsable && !hadError) {
     auto &diags = dc->getASTContext().Diags;
     Diag<> msg = diag::invalid_diagnostic;
@@ -970,7 +997,7 @@ bool swift::checkFallthroughStmt(FallthroughStmt *FS) {
   // decls. So if we match against the case body var decls,
   // transitively we will match all of the other case label items in
   // the fallthrough destination as well.
-  auto previousVars = previousBlock->getCaseBodyVariablesOrEmptyArray();
+  auto previousVars = previousBlock->getCaseBodyVariables();
   for (auto *expected : vars) {
     bool matched = false;
     if (!expected->hasName())
@@ -1075,7 +1102,7 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
     assert(TheFunc && "Should have bailed from pre-check if this is None");
 
     Type ResultTy = TheFunc->getBodyResultType();
-    if (!ResultTy || ResultTy->hasError())
+    if (!ResultTy)
       return nullptr;
 
     if (!RS->hasResult()) {
@@ -1085,12 +1112,33 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
       return RS;
     }
 
+    auto *accessor = TheFunc->getAccessorDecl();
+    auto *exprToCheck = RS->getResult();
+    InOutExpr *inout = nullptr;
+
+    if (accessor && accessor->isMutateAccessor()) {
+      // Check that the returned expression is a &.
+      if ((inout = dyn_cast<InOutExpr>(exprToCheck))) {
+        ResultTy = InOutType::get(ResultTy);
+      } else {
+        getASTContext()
+            .Diags
+            .diagnose(exprToCheck->getLoc(), diag::missing_address_of_return)
+            .highlight(exprToCheck->getSourceRange());
+        inout = new (getASTContext()) InOutExpr(
+            exprToCheck->getStartLoc(), exprToCheck, Type(), /*implicit*/ true);
+      }
+    }
     using namespace constraints;
-    auto target = SyntacticElementTarget::forReturn(RS, ResultTy, DC);
+    auto target =
+        SyntacticElementTarget::forReturn(RS, exprToCheck, ResultTy, DC);
     auto resultTarget = TypeChecker::typeCheckTarget(target);
     if (resultTarget) {
       RS->setResult(resultTarget->getAsExpr());
     } else {
+      // Update the expression even if type-checking failed as e.g pre-checking
+      // may have folded a sequence expr.
+      RS->setResult(target.getAsExpr());
       tryDiagnoseUnnecessaryCastOverOptionSet(getASTContext(), RS->getResult(),
                                               ResultTy);
     }
@@ -1234,8 +1282,8 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
     if (!fn) {
       // Then we're not in some type's member function; emit diagnostics.
       if (auto decl = outerDC->getAsDecl()) {
-        ctx.Diags.diagnose(DS->getDiscardLoc(), diag::discard_wrong_context_decl,
-                           decl->getDescriptiveKind());
+        ctx.Diags.diagnose(DS->getDiscardLoc(),
+                           diag::discard_wrong_context_decl, decl);
       } else if (isa<AbstractClosureExpr>(outerDC)) {
         ctx.Diags.diagnose(DS->getDiscardLoc(),
                            diag::discard_wrong_context_closure);
@@ -1252,8 +1300,8 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
 
       if (fn->isStatic() || isa<DestructorDecl>(fn)
           || isa<ConstructorDecl>(fn)) {
-        ctx.Diags.diagnose(DS->getDiscardLoc(), diag::discard_wrong_context_decl,
-                           fn->getDescriptiveKind());
+        ctx.Diags.diagnose(DS->getDiscardLoc(),
+                           diag::discard_wrong_context_decl, fn);
         diagnosed = true;
       }
     }
@@ -1265,10 +1313,9 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
           fn->mapTypeIntoContext(nominalDecl->getDeclaredInterfaceType());
 
       // must be noncopyable
-      if (!nominalType->isNoncopyable()) {
+      if (nominalType->isCopyable()) {
         ctx.Diags.diagnose(DS->getDiscardLoc(),
-                           diag::discard_wrong_context_copyable,
-                           fn->getDescriptiveKind());
+                           diag::discard_wrong_context_copyable);
         diagnosed = true;
 
       // has to have a deinit or else it's pointless.
@@ -1343,7 +1390,7 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
         case SelfAccessKind::Mutating:
           ctx.Diags.diagnose(DS->getDiscardLoc(),
                              diag::discard_wrong_context_nonconsuming,
-                             fn->getDescriptiveKind());
+                             funcDecl);
           diagnosed = true;
           break;
         }
@@ -1434,8 +1481,15 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
   }
   
   Stmt *visitForEachStmt(ForEachStmt *S) {
-    if (TypeChecker::typeCheckForEachPreamble(DC, S))
-      return nullptr;
+    // If we're performing IDE inspection, we also want to skip the where
+    // clause if we're leaving the body unchecked.
+    // FIXME: This is a hack to avoid cycles through NamingPatternRequest when
+    // doing lazy type-checking, we ought to fix the request to be granular in
+    // the type-checking work it kicks.
+    bool skipWhere = LeaveBraceStmtBodyUnchecked &&
+      Ctx.SourceMgr.hasIDEInspectionTargetBuffer();
+
+    TypeChecker::typeCheckForEachPreamble(DC, S, skipWhere);
 
     // Type-check the body of the loop.
     auto sourceFile = DC->getParentSourceFile();
@@ -1580,9 +1634,7 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
 
     // First pass: check all of the bindings.
     for (auto *caseBlock : make_range(casesBegin, casesEnd)) {
-      // Bind all of the pattern variables together so we can follow the
-      // "parent" pointers later on.
-      bindSwitchCasePatternVars(DC, caseBlock);
+      diagnoseCaseVarMutabilityMismatch(DC, caseBlock);
 
       auto caseLabelItemArray = caseBlock->getMutableCaseLabelItems();
       for (auto &labelItem : caseLabelItemArray) {
@@ -1599,7 +1651,7 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
       }
 
       // Setup the types of our case body var decls.
-      for (auto *expected : caseBlock->getCaseBodyVariablesOrEmptyArray()) {
+      for (auto *expected : caseBlock->getCaseBodyVariables()) {
         assert(expected->hasName());
         auto prev = expected->getParentVarDecl();
         if (prev->hasInterfaceType())
@@ -1885,7 +1937,26 @@ void TypeChecker::checkIgnoredExpr(Expr *E) {
                     : valueE;
 
     if (auto *Fn = dyn_cast<ApplyExpr>(expr)) {
-      if (auto *calledValue = Fn->getCalledValue()) {
+      /// Some concurrency-related things may have intermediate conversions that
+      /// we want to look through, e.g.
+      ///
+      /// ```swift
+      /// @discardableResult
+      /// @MainActor
+      /// func foo() -> () -> Void {
+      ///   return {}
+      /// }
+      ///
+      /// @MainActor
+      /// func test() {
+      ///   foo()
+      ///   // ^ return value implicitly wapped in a `@Sendable` conversion
+      /// }
+      /// ```
+      /// Attempt to look through function conversions when resolving the
+      /// called value.
+      if (auto *calledValue =
+              Fn->getCalledValue(/*skipFunctionConversions=*/true)) {
         if (auto *FD = dyn_cast<AbstractFunctionDecl>(calledValue)) {
           if (FD->getAttrs().hasAttribute<DiscardableResultAttr>()) {
             isDiscardable = true;
@@ -2463,12 +2534,29 @@ bool TypeCheckASTNodeAtLocRequest::evaluate(
       return MacroWalking::ArgumentsAndExpansion;
     }
 
+    /// Checks whether the given range, when treated as a character range,
+    /// contains the searched location.
+    bool charRangeContainsLoc(SourceRange range) {
+      if (!range)
+        return false;
+
+      if (SM.isBefore(Loc, range.Start))
+        return false;
+
+      // NOTE: We need to check the character loc here because the target
+      // loc can be inside the last token of the node. i.e. interpolated
+      // string.
+      return SM.isBefore(Loc, Lexer::getLocForEndOfToken(SM, range.End));
+    }
+
     PreWalkResult<Stmt *> walkToStmtPre(Stmt *S) override {
       if (auto *brace = dyn_cast<BraceStmt>(S)) {
-        auto braceCharRange = Lexer::getCharSourceRangeFromSourceRange(
-            SM, brace->getSourceRange());
+        auto braceRange = brace->getSourceRange();
+        auto braceCharRange = SourceRange(
+            braceRange.Start, Lexer::getLocForEndOfToken(SM, braceRange.End));
+
         // Unless this brace contains the loc, there's nothing to do.
-        if (!braceCharRange.contains(Loc))
+        if (!SM.containsLoc(braceCharRange, Loc))
           return Action::SkipNode(S);
 
         // Reset the node found in a parent context if it's not part of this
@@ -2478,22 +2566,22 @@ bool TypeCheckASTNodeAtLocRequest::evaluate(
         // syntactically part of the brace stmt's range but won't be walked as
         // a child of the brace stmt.
         if (!brace->isImplicit() && FoundNode) {
-          auto foundNodeCharRange = Lexer::getCharSourceRangeFromSourceRange(
-              SM, FoundNode->getSourceRange());
-          if (!braceCharRange.contains(foundNodeCharRange)) {
+          auto foundRange = FoundNode->getSourceRange();
+          auto foundCharRange = SourceRange(
+              foundRange.Start, Lexer::getLocForEndOfToken(SM, foundRange.End));
+          if (!SM.encloses(braceCharRange, foundCharRange))
             FoundNode = nullptr;
-          }
         }
 
         for (ASTNode &node : brace->getElements()) {
-          if (SM.isBeforeInBuffer(Loc, node.getStartLoc()))
+          auto range = node.getSourceRange();
+          if (SM.isBefore(Loc, range.Start))
             break;
 
           // NOTE: We need to check the character loc here because the target
           // loc can be inside the last token of the node. i.e. interpolated
           // string.
-          SourceLoc endLoc = Lexer::getLocForEndOfToken(SM, node.getEndLoc());
-          if (SM.isBeforeInBuffer(endLoc, Loc) || endLoc == Loc)
+          if (!SM.isBefore(Loc, Lexer::getLocForEndOfToken(SM, range.End)))
             continue;
 
           // 'node' may be the target node, except 'CaseStmt' which cannot be
@@ -2510,13 +2598,11 @@ bool TypeCheckASTNodeAtLocRequest::evaluate(
         return Action::Stop();
       } else if (auto Conditional = dyn_cast<LabeledConditionalStmt>(S)) {
         for (StmtConditionElement &Cond : Conditional->getCond()) {
-          if (SM.isBeforeInBuffer(Loc, Cond.getStartLoc())) {
+          auto range = Cond.getSourceRange();
+          if (SM.isBefore(Loc, range.Start))
             break;
-          }
-          SourceLoc endLoc = Lexer::getLocForEndOfToken(SM, Cond.getEndLoc());
-          if (SM.isBeforeInBuffer(endLoc, Loc) || endLoc == Loc) {
+          if (!SM.isBefore(Loc, Lexer::getLocForEndOfToken(SM, range.End)))
             continue;
-          }
 
           FoundNodeStorage = ASTNode(&Cond);
           FoundNode = &FoundNodeStorage;
@@ -2528,11 +2614,7 @@ bool TypeCheckASTNodeAtLocRequest::evaluate(
     }
 
     PreWalkResult<Expr *> walkToExprPre(Expr *E) override {
-      if (SM.isBeforeInBuffer(Loc, E->getStartLoc()))
-        return Action::SkipNode(E);
-
-      SourceLoc endLoc = Lexer::getLocForEndOfToken(SM, E->getEndLoc());
-      if (SM.isBeforeInBuffer(endLoc, Loc))
+      if (!charRangeContainsLoc(E->getSourceRange()))
         return Action::SkipNode(E);
 
       // Don't walk into 'TapExpr'. They should be type checked with parent
@@ -2547,9 +2629,7 @@ bool TypeCheckASTNodeAtLocRequest::evaluate(
       if (auto *SVE = dyn_cast<SingleValueStmtExpr>(E)) {
         SmallVector<Expr *> scratch;
         for (auto *result : SVE->getResultExprs(scratch)) {
-          auto resultCharRange = Lexer::getCharSourceRangeFromSourceRange(
-            SM, result->getSourceRange());
-          if (resultCharRange.contains(Loc)) {
+          if (charRangeContainsLoc(result->getSourceRange())) {
             if (!result->walk(*this))
               return Action::Stop();
 
@@ -2571,20 +2651,15 @@ bool TypeCheckASTNodeAtLocRequest::evaluate(
     }
 
     PreWalkAction walkToDeclPre(Decl *D) override {
+      if (!charRangeContainsLoc(D->getSourceRange()))
+        return Action::SkipNode();
+
       if (auto *newDC = dyn_cast<DeclContext>(D))
         DC = newDC;
 
-      if (!SM.isBeforeInBuffer(Loc, D->getStartLoc())) {
-        // NOTE: We need to check the character loc here because the target
-        // loc can be inside the last token of the node. i.e. interpolated
-        // string.
-        SourceLoc endLoc = Lexer::getLocForEndOfToken(SM, D->getEndLoc());
-        if (!(SM.isBeforeInBuffer(endLoc, Loc) || endLoc == Loc)) {
-          if (!isa<TopLevelCodeDecl>(D)) {
-            FoundNodeStorage = ASTNode(D);
-            FoundNode = &FoundNodeStorage;
-          }
-        }
+      if (!isa<TopLevelCodeDecl>(D)) {
+        FoundNodeStorage = ASTNode(D);
+        FoundNode = &FoundNodeStorage;
       }
       return Action::Continue();
     }
@@ -2647,18 +2722,28 @@ bool TypeCheckASTNodeAtLocRequest::evaluate(
   // function, we unfortunately need to type-check everything since we need to
   // apply the solution.
   // FIXME: We ought to see if we can do better in that case.
-  if (auto *CE = DC->getInnermostClosureForCaptures()) {
-    if (CE->getBodyState() == ClosureExpr::BodyState::Parsed) {
-      swift::typeCheckASTNodeAtLoc(
-          TypeCheckASTNodeAtLocContext::declContext(CE->getParent()),
-          CE->getLoc());
-
-      // If the context itself is a ClosureExpr, we should have type-checked
-      // the completion expression now. If it's a nested local declaration,
-      // fall through to type-check the AST node now that we've type-checked
-      // the surrounding closure.
-      if (isa<ClosureExpr>(DC))
-        return false;
+  //
+  // We don't need to do this for unattached nodes since we already would have
+  // type-checked the surrounding context, and unattached nodes cannot be
+  // typechecked via DeclContext since they aren't actually part of the AST.
+  if (!typeCheckCtx.isForUnattachedNode()) {
+    if (auto *CE = DC->getInnermostClosureForCaptures()) {
+      // Walk up to the parent-most closure.
+      while (auto *parent = dyn_cast_or_null<ClosureExpr>(CE->getParent()))
+        CE = parent;
+
+      if (CE->getBodyState() == ClosureExpr::BodyState::Parsed) {
+        swift::typeCheckASTNodeAtLoc(
+            TypeCheckASTNodeAtLocContext::declContext(CE->getParent()),
+            CE->getLoc());
+
+        // If the context itself is a ClosureExpr, we should have type-checked
+        // the completion expression now. If it's a nested local declaration,
+        // fall through to type-check the AST node now that we've type-checked
+        // the surrounding closure.
+        if (isa<ClosureExpr>(DC))
+          return false;
+      }
     }
   }
 
@@ -3165,6 +3250,12 @@ IsSingleValueStmtRequest::evaluate(Evaluator &eval, const Stmt *S,
     return areBranchesValidForSingleValueStmt(ctx, DCS,
                                               DCS->getBranches(scratch));
   }
+  if (auto *FS = dyn_cast<ForEachStmt>(S)) {
+    if (!ctx.LangOpts.hasFeature(Feature::ForExpressions))
+      return IsSingleValueStmtResult::unhandledStmt();
+
+    return areBranchesValidForSingleValueStmt(ctx, FS, FS->getBody());
+  }
   return IsSingleValueStmtResult::unhandledStmt();
 }
 
@@ -3204,7 +3295,8 @@ void swift::checkUnknownAttrRestrictions(
   }
 }
 
-void swift::bindSwitchCasePatternVars(DeclContext *dc, CaseStmt *caseStmt) {
+void swift::diagnoseCaseVarMutabilityMismatch(DeclContext *dc,
+                                              CaseStmt *caseStmt) {
   llvm::SmallDenseMap<Identifier, std::pair<VarDecl *, bool>, 4> latestVars;
   auto recordVar = [&](Pattern *pattern, VarDecl *var) {
     if (!var->hasName())
@@ -3214,16 +3306,10 @@ void swift::bindSwitchCasePatternVars(DeclContext *dc, CaseStmt *caseStmt) {
     // parent of this new variable.
     auto &entry = latestVars[var->getName()];
     if (entry.first) {
-      assert(!var->getParentVarDecl() ||
-             var->getParentVarDecl() == entry.first);
-      var->setParentVarDecl(entry.first);
-
       // Check for a mutability mismatch.
-      if (pattern && entry.second != var->isLet()) {
+      if (entry.second != var->isLet()) {
         // Find the original declaration.
-        auto initialCaseVarDecl = entry.first;
-        while (auto parentVar = initialCaseVarDecl->getParentVarDecl())
-          initialCaseVarDecl = parentVar;
+        auto initialCaseVarDecl = entry.first->getCanonicalVarDecl();
 
         auto diag = var->diagnose(diag::mutability_mismatch_multiple_pattern_list,
                                   var->isLet(), initialCaseVarDecl->isLet());
@@ -3234,10 +3320,10 @@ void swift::bindSwitchCasePatternVars(DeclContext *dc, CaseStmt *caseStmt) {
             if (VP->getSingleVar() == var)
               foundVP = VP;
         });
-        if (foundVP)
+        if (foundVP) {
           diag.fixItReplace(foundVP->getLoc(),
                             initialCaseVarDecl->isLet() ? "let" : "var");
-
+        }
         var->setInvalid();
         initialCaseVarDecl->setInvalid();
       }
@@ -3249,8 +3335,6 @@ void swift::bindSwitchCasePatternVars(DeclContext *dc, CaseStmt *caseStmt) {
     entry.first = var;
   };
 
-  // Wire up the parent var decls for each variable that occurs within
-  // the patterns of each case item. in source order.
   for (auto &caseItem : caseStmt->getMutableCaseLabelItems()) {
     // Resolve the pattern.
     auto *pattern = caseItem.getPattern();
@@ -3266,11 +3350,6 @@ void swift::bindSwitchCasePatternVars(DeclContext *dc, CaseStmt *caseStmt) {
       recordVar(pattern, var);
     });
   }
-
-  // Wire up the case body variables to the latest patterns.
-  for (auto bodyVar : caseStmt->getCaseBodyVariablesOrEmptyArray()) {
-    recordVar(nullptr, bodyVar);
-  }
 }
 
 FuncDecl *TypeChecker::getForEachIteratorNextFunction(
diff --git a/lib/Sema/TypeCheckStorage.cpp b/lib/Sema/TypeCheckStorage.cpp
index 6604929cb050e..411582b6f09b8 100644
--- a/lib/Sema/TypeCheckStorage.cpp
+++ b/lib/Sema/TypeCheckStorage.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -451,12 +451,6 @@ const PatternBindingEntry *PatternBindingEntryRequest::evaluate(
   auto contextualPattern =
       ContextualPattern::forPatternBindingDecl(binding, entryNumber);
   Type patternType = TypeChecker::typeCheckPattern(contextualPattern);
-  if (patternType->hasError()) {
-    swift::setBoundVarsTypeError(pattern, Context);
-    binding->setInvalid();
-    pattern->setType(ErrorType::get(Context));
-    return &pbe;
-  }
 
   llvm::SmallVector<VarDecl *, 2> vars;
   binding->getPattern(entryNumber)->collectVariables(vars);
@@ -516,9 +510,7 @@ const PatternBindingEntry *PatternBindingEntryRequest::evaluate(
 
   // If the pattern contains some form of unresolved type, we'll need to
   // check the initializer.
-  if (patternType->hasUnresolvedType() ||
-      patternType->hasPlaceholder() ||
-      patternType->hasUnboundGenericType()) {
+  if (patternType->hasPlaceholder() || patternType->hasUnboundGenericType()) {
     if (TypeChecker::typeCheckPatternBinding(binding, entryNumber,
                                              patternType)) {
       binding->setInvalid();
@@ -591,8 +583,6 @@ static void checkAndContextualizePatternBindingInit(PatternBindingDecl *binding,
                                                     unsigned i) {
   // Force the entry to be checked.
   (void)binding->getCheckedPatternBindingEntry(i);
-  if (binding->isInvalid())
-    return;
 
   if (!binding->isInitialized(i))
     return;
@@ -600,9 +590,6 @@ static void checkAndContextualizePatternBindingInit(PatternBindingDecl *binding,
   if (!binding->isInitializerChecked(i))
     TypeChecker::typeCheckPatternBinding(binding, i);
 
-  if (binding->isInvalid())
-    return;
-
   // If we entered an initializer context, contextualize any auto-closures we
   // might have created. Note that we don't contextualize the initializer for a
   // property with a wrapper, because the initializer will have been subsumed by
@@ -619,6 +606,9 @@ static void checkAndContextualizePatternBindingInit(PatternBindingDecl *binding,
     auto *init = binding->getInit(i);
     TypeChecker::contextualizeExpr(init, initContext);
   }
+
+  // Compute captures in case diagnostics are emitted.
+  (void)binding->getCaptureInfo(i);
 }
 
 Expr *PatternBindingCheckedAndContextualizedInitRequest::evaluate(
@@ -645,6 +635,9 @@ directAccessorKindForReadImpl(ReadImplKind reader) {
 
   case ReadImplKind::Read2:
     return AccessorKind::Read2;
+
+  case ReadImplKind::Borrow:
+    return AccessorKind::Borrow;
   }
   llvm_unreachable("bad impl kind");
 }
@@ -839,6 +832,9 @@ IsSetterMutatingRequest::evaluate(Evaluator &evaluator,
 
   case WriteImplKind::Modify2:
     return storage->getParsedAccessor(AccessorKind::Modify2)->isMutating();
+
+  case WriteImplKind::Mutate:
+    return storage->getParsedAccessor(AccessorKind::Mutate)->isMutating();
   }
   llvm_unreachable("bad storage kind");
 }
@@ -846,6 +842,10 @@ IsSetterMutatingRequest::evaluate(Evaluator &evaluator,
 OpaqueReadOwnership
 OpaqueReadOwnershipRequest::evaluate(Evaluator &evaluator,
                                      AbstractStorageDecl *storage) const {
+  auto abiRole = ABIRoleInfo(storage);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return abiRole.getCounterpart()->getOpaqueReadOwnership();
+
   enum class DiagKind {
     BorrowedAttr,
     NoncopyableType
@@ -856,12 +856,10 @@ OpaqueReadOwnershipRequest::evaluate(Evaluator &evaluator,
     if (auto *getter = storage->getEffectfulGetAccessor()) {
       switch (kind) {
       case DiagKind::NoncopyableType:
-        getter->diagnose(diag::noncopyable_effectful_getter,
-                         getter->getDescriptiveKind());
+        getter->diagnose(diag::noncopyable_effectful_getter, getter);
         break;
       case DiagKind::BorrowedAttr:
-        getter->diagnose(diag::borrowed_with_effect,
-                         getter->getDescriptiveKind());
+        getter->diagnose(diag::borrowed_with_effect, getter);
         break;
       }
     }
@@ -883,6 +881,9 @@ OpaqueReadOwnershipRequest::evaluate(Evaluator &evaluator,
   if (storage->getAccessor(AccessorKind::Read2))
     return OpaqueReadOwnership::Borrowed;
 
+  if (storage->getAccessor(AccessorKind::Borrow))
+    return OpaqueReadOwnership::Borrowed;
+
   if (storage->getAttrs().hasAttribute<BorrowedAttr>())
     return usesBorrowed(DiagKind::BorrowedAttr);
 
@@ -1058,7 +1059,7 @@ getPropertyWrapperLValueness(VarDecl *var) {
 ///     - Wrapped: \c self._member.wrappedValue
 ///     - Composition: \c self._member.wrappedValue.wrappedValue….wrappedValue
 ///     - Projected: \c self._member.projectedValue
-///     - Enclosed instance: \c Wrapper[_enclosedInstance: self, …]
+///     - Enclosed instance: \c Wrapper[_enclosingInstance: self, …]
 static Expr *buildStorageReference(AccessorDecl *accessor,
                                    AbstractStorageDecl *storage,
                                    TargetImpl target,
@@ -1141,12 +1142,7 @@ static Expr *buildStorageReference(AccessorDecl *accessor,
       auto *baseClass = override->getDeclContext()->getSelfClassDecl();
       selfTypeForAccess = selfTypeForAccess->getSuperclassForDecl(baseClass);
 
-      // Error recovery path. We get an ErrorType here if getSuperclassForDecl()
-      // fails (because, for instance, a generic parameter of a generic nominal
-      // type cannot be resolved).
-      if (!selfTypeForAccess->is<ErrorType>()) {
-        subs = selfTypeForAccess->getContextSubstitutionMap(baseClass);
-      }
+      subs = selfTypeForAccess->getContextSubstitutionMap(baseClass);
 
       storage = override;
 
@@ -1803,6 +1799,9 @@ synthesizeGetterBody(AccessorDecl *getter, ASTContext &ctx) {
 
   case ReadImplKind::Read2:
     return synthesizeRead2CoroutineGetterBody(getter, ctx);
+
+  case ReadImplKind::Borrow:
+    llvm_unreachable("borrow accessor is not yet implemented");
   }
   llvm_unreachable("bad ReadImplKind");
 }
@@ -2070,6 +2069,9 @@ synthesizeSetterBody(AccessorDecl *setter, ASTContext &ctx) {
 
   case WriteImplKind::Modify2:
     return synthesizeModify2CoroutineSetterBody(setter, ctx);
+
+  case WriteImplKind::Mutate:
+    llvm_unreachable("synthesizing setter from mutate");
   }
   llvm_unreachable("bad WriteImplKind");
 }
@@ -2283,6 +2285,12 @@ synthesizeAccessorBody(AbstractFunctionDecl *fn, void *) {
 
   case AccessorKind::Init:
     llvm_unreachable("init accessor not yet implemented");
+
+  case AccessorKind::Borrow:
+    llvm_unreachable("borrow accessor is not yet implemented");
+
+  case AccessorKind::Mutate:
+    llvm_unreachable("mutate accessor is not yet implemented");
   }
   llvm_unreachable("bad synthesized function kind");
 }
@@ -2467,6 +2475,8 @@ static AccessorDecl *createSetterPrototype(AbstractStorageDecl *storage,
       asAvailableAs.push_back(mod);
     }
     break;
+  case WriteImplKind::Mutate:
+    llvm_unreachable("mutate accessor is not yet implemented");
   }
   
   if (!asAvailableAs.empty()) {
@@ -2605,8 +2615,7 @@ SynthesizeAccessorRequest::evaluate(Evaluator &evaluator,
     return createModify2CoroutinePrototype(storage, ctx);
 
 #define OPAQUE_ACCESSOR(ID, KEYWORD)
-#define ACCESSOR(ID) \
-  case AccessorKind::ID:
+#define ACCESSOR(ID, KEYWORD) case AccessorKind::ID:
 #include "swift/AST/AccessorKinds.def"
     llvm_unreachable("not an opaque accessor");
   }
@@ -2669,25 +2678,42 @@ RequiresOpaqueAccessorsRequest::evaluate(Evaluator &evaluator,
 ///
 /// The underscored accessor could, however, still be required for ABI
 /// stability.
-bool AbstractStorageDecl::requiresCorrespondingUnderscoredCoroutineAccessor(
-    AccessorKind kind, AccessorDecl const *decl) const {
-  auto &ctx = getASTContext();
+static bool requiresCorrespondingUnderscoredCoroutineAccessorImpl(
+    AbstractStorageDecl const *storage, AccessorKind kind,
+    AccessorDecl const *decl, AbstractStorageDecl const *derived) {
+  auto &ctx = storage->getASTContext();
   assert(ctx.LangOpts.hasFeature(Feature::CoroutineAccessors));
   assert(kind == AccessorKind::Modify2 || kind == AccessorKind::Read2);
 
+  // If any overridden decl requires the underscored version, then this decl
+  // does too.  Otherwise dispatch to the underscored version on a value
+  // statically the super but dynamically this subtype would not dispatch to an
+  // override of the underscored version but rather (incorrectly) the
+  // supertype's implementation.
+  if (storage == derived) {
+    auto *current = storage;
+    while ((current = current->getOverriddenDecl())) {
+      auto *currentDecl = cast_or_null<AccessorDecl>(
+          decl ? decl->getOverriddenDecl() : nullptr);
+      if (requiresCorrespondingUnderscoredCoroutineAccessorImpl(
+              current, kind, currentDecl, derived)) {
+        return true;
+      }
+    }
+  }
+
   // Non-stable modules have no ABI to keep stable.
-  if (getModuleContext()->getResilienceStrategy() !=
+  if (storage->getModuleContext()->getResilienceStrategy() !=
       ResilienceStrategy::Resilient)
     return false;
 
   // Non-exported storage has no ABI to keep stable.
-  if (!isExported(this))
+  if (!isExported(storage))
     return false;
 
   // The non-underscored accessor is not present, the underscored accessor
   // won't be either.
-  // TODO: CoroutineAccessors: What if only the underscored is written out?
-  auto *accessor = decl ? decl : getOpaqueAccessor(kind);
+  auto *accessor = decl ? decl : storage->getOpaqueAccessor(kind);
   if (!accessor)
     return false;
 
@@ -2698,17 +2724,43 @@ bool AbstractStorageDecl::requiresCorrespondingUnderscoredCoroutineAccessor(
   if (!ctx.supportsVersionedAvailability())
     return true;
 
-  auto modifyAvailability = AvailabilityContext::forLocation({}, accessor);
-  auto featureAvailability = ctx.getCoroutineAccessorsRuntimeAvailability();
+  AvailabilityContext accessorAvailability = [&] {
+    if (storage->getModuleContext()->isMainModule()) {
+      return AvailabilityContext::forDeclSignature(accessor);
+    }
+    // Calculate the availability of the imported declaration ourselves starting
+    // from always available and constraining by walking the enclosing decl
+    // contexts.
+    auto retval = AvailabilityContext::forAlwaysAvailable(ctx);
+    auto declContext = storage->getInnermostDeclContext();
+    while (declContext) {
+      const Decl *decl = declContext->getInnermostDeclarationDeclContext();
+      if (!decl)
+        break;
+
+      retval.constrainWithDecl(decl);
+      declContext = decl->getDeclContext();
+    }
+    return retval;
+  }();
+  auto featureAvailability = ctx.getCoroutineAccessorsAvailability();
   // If accessor was introduced only after the feature was, there's no old ABI
   // to maintain.
-  if (modifyAvailability.getPlatformRange().isContainedIn(featureAvailability))
+  if (accessorAvailability.getPlatformRange().isContainedIn(
+          featureAvailability))
     return false;
 
   // The underscored accessor is required for ABI stability.
   return true;
 }
 
+bool AbstractStorageDecl::requiresCorrespondingUnderscoredCoroutineAccessor(
+    AccessorKind kind, AccessorDecl const *decl) const {
+  return requiresCorrespondingUnderscoredCoroutineAccessorImpl(
+      this, kind, decl,
+      /*derived=*/this);
+}
+
 bool RequiresOpaqueModifyCoroutineRequest::evaluate(
     Evaluator &evaluator, AbstractStorageDecl *storage,
     bool isUnderscored) const {
@@ -2752,6 +2804,11 @@ bool RequiresOpaqueModifyCoroutineRequest::evaluate(
     if (protoDecl->isObjC())
       return false;
 
+  // If a mutate accessor is present, we don't need a modify coroutine
+  if (storage->getAccessor(AccessorKind::Mutate)) {
+    return false;
+  }
+
   return true;
 }
 
@@ -2859,8 +2916,11 @@ IsAccessorTransparentRequest::evaluate(Evaluator &evaluator,
         break;
       }
 
-      // Anything else should not have a synthesized setter.
-      LLVM_FALLTHROUGH;
+      // Anything else we'll synthesize an invalid setter for in
+      // `synthesizeSetterBody`, this happens for cases such as stored
+      // properties defined in extensions or enums, we implicitly treat them as
+      // computed.
+      return false;
     case WriteImplKind::Immutable:
       if (accessor->getASTContext().LangOpts.AllowModuleWithCompilerErrors)
         return false;
@@ -2878,6 +2938,8 @@ IsAccessorTransparentRequest::evaluate(Evaluator &evaluator,
     case WriteImplKind::Modify:
     case WriteImplKind::Modify2:
       break;
+    case WriteImplKind::Mutate:
+      llvm_unreachable("mutate accessor is not yet implemented");
     }
     break;
 
@@ -2887,12 +2949,15 @@ IsAccessorTransparentRequest::evaluate(Evaluator &evaluator,
   case AccessorKind::Modify2:
   case AccessorKind::Init:
     break;
-
+  case AccessorKind::Borrow:
+    llvm_unreachable("borrow accessor is not yet implemented");
   case AccessorKind::WillSet:
   case AccessorKind::DidSet:
   case AccessorKind::Address:
   case AccessorKind::MutableAddress:
     llvm_unreachable("bad synthesized function kind");
+  case AccessorKind::Mutate:
+    llvm_unreachable("mutate accessor is not yet implemented");
   }
 
   switch (storage->getReadWriteImpl()) {
@@ -2953,9 +3018,10 @@ LazyStoragePropertyRequest::evaluate(Evaluator &evaluator,
   addMemberToContextIfNeeded(PBD, VD->getDeclContext(), Storage);
 
   // Make sure the original init is marked as subsumed.
-  auto *originalPBD = VD->getParentPatternBinding();
-  auto originalIndex = originalPBD->getPatternEntryIndexForVarDecl(VD);
-  originalPBD->setInitializerSubsumed(originalIndex);
+  if (auto *originalPBD = VD->getParentPatternBinding()) {
+    auto originalIndex = originalPBD->getPatternEntryIndexForVarDecl(VD);
+    originalPBD->setInitializerSubsumed(originalIndex);
+  }
 
   return Storage;
 }
@@ -3776,11 +3842,13 @@ bool HasStorageRequest::evaluate(Evaluator &evaluator,
       storage->getParsedAccessor(AccessorKind::Read) ||
       storage->getParsedAccessor(AccessorKind::Read2) ||
       storage->getParsedAccessor(AccessorKind::Address) ||
+      storage->getParsedAccessor(AccessorKind::Borrow) ||
       storage->getParsedAccessor(AccessorKind::Set) ||
       storage->getParsedAccessor(AccessorKind::Modify) ||
       storage->getParsedAccessor(AccessorKind::Modify2) ||
       storage->getParsedAccessor(AccessorKind::MutableAddress) ||
-      storage->getParsedAccessor(AccessorKind::Init))
+      storage->getParsedAccessor(AccessorKind::Init) ||
+      storage->getParsedAccessor(AccessorKind::Mutate))
     return false;
 
   // willSet or didSet in an overriding property imply that there is no storage.
@@ -3844,6 +3912,10 @@ void HasStorageRequest::cacheResult(bool hasStorage) const {
 StorageImplInfo
 StorageImplInfoRequest::evaluate(Evaluator &evaluator,
                                  AbstractStorageDecl *storage) const {
+  auto abiRole = ABIRoleInfo(storage);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return abiRole.getCounterpart()->getImplInfo();
+
   if (auto *param = dyn_cast<ParamDecl>(storage)) {
     return StorageImplInfo::getSimpleStored(
       param->isImmutableInFunctionBody()
@@ -3859,9 +3931,8 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
     // If we see `@_hasStorage` in a context with no stored properties, diagnose
     // and ignore it.
     if (isa<ExtensionDecl, EnumDecl, ProtocolDecl>(DC)) {
-      storage->diagnose(diag::attr_invalid_in_context, attr,
-                        DC->getAsDecl()->getDescriptiveKind())
-        .warnInSwiftInterface(storage->getDeclContext());
+      storage->diagnose(diag::attr_invalid_in_context, attr, DC->getAsDecl())
+          .warnInSwiftInterface(storage->getDeclContext());
 
     // Allow the @_hasStorage attribute to override all the accessors we parsed
     // when making the final classification.
@@ -3959,8 +4030,10 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
   bool hasModify2 = storage->getParsedAccessor(AccessorKind::Modify2);
   bool hasMutableAddress = storage->getParsedAccessor(AccessorKind::MutableAddress);
   bool hasInit = storage->getParsedAccessor(AccessorKind::Init);
+  auto *borrow = storage->getParsedAccessor(AccessorKind::Borrow);
+  auto *mutate = storage->getParsedAccessor(AccessorKind::Mutate);
 
-  // 'get', 'read', and a non-mutable addressor are all exclusive.
+  // 'get', 'read', 'borrow' and a non-mutable addressor are all exclusive.
   ReadImplKind readImpl;
   if (storage->getParsedAccessor(AccessorKind::Get)) {
     readImpl = ReadImplKind::Get;
@@ -3970,11 +4043,13 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
     readImpl = ReadImplKind::Read;
   } else if (storage->getParsedAccessor(AccessorKind::Address)) {
     readImpl = ReadImplKind::Address;
+  } else if (storage->getParsedAccessor(AccessorKind::Borrow)) {
+    readImpl = ReadImplKind::Borrow;
 
-  // If there's a writing accessor of any sort, there must also be a
-  // reading accessor.
+    // If there's a writing accessor of any sort, there must also be a
+    // reading accessor.
   } else if (hasInit || hasSetter || hasModify || hasModify2 ||
-             hasMutableAddress) {
+             hasMutableAddress || mutate) {
     readImpl = ReadImplKind::Get;
 
   // Subscripts always have to have some sort of accessor; they can't be
@@ -4003,7 +4078,7 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
     readImpl = ReadImplKind::Stored;
   }
 
-  // Prefer using 'set' and 'modify' over a mutable addressor.
+  // Prefer using 'set', 'mutate' and 'modify' over a mutable addressor.
   WriteImplKind writeImpl;
   ReadWriteImplKind readWriteImpl;
   if (hasSetter) {
@@ -4015,6 +4090,9 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
     } else {
       readWriteImpl = ReadWriteImplKind::MaterializeToTemporary;
     }
+  } else if (mutate) {
+    writeImpl = WriteImplKind::Mutate;
+    readWriteImpl = ReadWriteImplKind::Mutate;
   } else if (hasModify2) {
     writeImpl = WriteImplKind::Modify2;
     readWriteImpl = ReadWriteImplKind::Modify2;
@@ -4055,6 +4133,24 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
     readWriteImpl = ReadWriteImplKind::Immutable;
   }
 
+  if (borrow || mutate) {
+    if (auto *extDecl = dyn_cast<ExtensionDecl>(DC)) {
+      auto extNominal = extDecl->getExtendedNominal();
+      if (!isa<StructDecl>(extNominal) && !isa<EnumDecl>(extNominal)) {
+        if (borrow) {
+          storage->getASTContext().Diags.diagnose(
+              borrow->getLoc(), diag::accessor_not_supported_in_decl,
+              "a borrow accessor");
+        }
+        if (mutate) {
+          storage->getASTContext().Diags.diagnose(
+              mutate->getLoc(), diag::accessor_not_supported_in_decl,
+              "a mutate accessor");
+        }
+      }
+    }
+  }
+
   StorageImplInfo info(readImpl, writeImpl, readWriteImpl);
   finishStorageImplInfo(storage, info);
 
diff --git a/lib/Sema/TypeCheckSwitchStmt.cpp b/lib/Sema/TypeCheckSwitchStmt.cpp
index 5e5faf5d0b3e9..a03fb5c1c7803 100644
--- a/lib/Sema/TypeCheckSwitchStmt.cpp
+++ b/lib/Sema/TypeCheckSwitchStmt.cpp
@@ -1154,19 +1154,34 @@ namespace {
         assert(defaultReason == RequiresDefault::No);
         Type subjectType = Switch->getSubjectExpr()->getType();
         bool shouldIncludeFutureVersionComment = false;
-        bool shouldDowngradeToWarning = true;
-        if (auto *theEnum = subjectType->getEnumOrBoundGenericEnum()) {
+        auto *theEnum = subjectType->getEnumOrBoundGenericEnum();
+
+        if (theEnum) {
           auto *enumModule = theEnum->getParentModule();
           shouldIncludeFutureVersionComment =
               enumModule->isSystemModule() ||
-              enumModule->supportsExtensibleEnums();
-          // Since the module enabled `ExtensibleEnums` feature they
-          // opted-in all of their clients into exhaustivity errors.
-          shouldDowngradeToWarning = !enumModule->supportsExtensibleEnums();
+              theEnum->getAttrs().hasAttribute<NonexhaustiveAttr>();
         }
-        DE.diagnose(startLoc, diag::non_exhaustive_switch_unknown_only,
-                    subjectType, shouldIncludeFutureVersionComment)
-          .warnUntilSwiftVersionIf(shouldDowngradeToWarning, 6);
+
+        auto diag =
+            DE.diagnose(startLoc, diag::non_exhaustive_switch_unknown_only,
+                        subjectType, shouldIncludeFutureVersionComment);
+
+        auto shouldWarnUntilVersion = [&theEnum]() -> unsigned {
+          if (theEnum) {
+            // Presence of `@nonexhaustive(warn)` pushes the warning farther,
+            // into the future.
+            if (auto *nonexhaustive =
+                    theEnum->getAttrs().getAttribute<NonexhaustiveAttr>()) {
+              if (nonexhaustive->getMode() == NonexhaustiveMode::Warning)
+                return swift::version::Version::getFutureMajorLanguageVersion();
+            }
+          }
+          return 6;
+        };
+
+        diag.warnUntilSwiftVersion(shouldWarnUntilVersion());
+
         mainDiagType = std::nullopt;
       }
         break;
@@ -1488,8 +1503,9 @@ namespace {
           // If there's no sub-pattern then there's no further recursive
           // structure here.  Yield the constructor space.
           // FIXME: Compound names.
-          return Space::forConstructor(
-              item->getType(), VP->getName().getBaseIdentifier(), std::nullopt);
+          return Space::forConstructor(item->getType(),
+                                       VP->getName().getBaseIdentifier(),
+                                       ArrayRef<Space>());
         }
 
         SmallVector<Space, 4> conArgSpace;
diff --git a/lib/Sema/TypeCheckType.cpp b/lib/Sema/TypeCheckType.cpp
index 3483e6d3c33e7..e9fcf14459e9e 100644
--- a/lib/Sema/TypeCheckType.cpp
+++ b/lib/Sema/TypeCheckType.cpp
@@ -10,15 +10,16 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file implements validation for Swift types, emitting semantic errors as
-// appropriate and checking default initializer values.
+// This file implements type resolution, which converts syntactic type
+// representations into semantic types, emitting diagnostics as appropriate.
 //
 //===----------------------------------------------------------------------===//
 
 #include "TypeCheckType.h"
-#include "AsyncCallerExecutionMigration.h"
+#include "NonisolatedNonsendingByDefaultMigration.h"
 #include "TypeCheckAvailability.h"
 #include "TypeCheckConcurrency.h"
+#include "TypeCheckEmbedded.h"
 #include "TypeCheckInvertible.h"
 #include "TypeCheckProtocol.h"
 #include "TypeChecker.h"
@@ -77,36 +78,40 @@ TypeResolution::forStructural(DeclContext *dc, TypeResolutionOptions options,
                               HandlePlaceholderTypeReprFn placeholderHandler,
                               OpenPackElementFn packElementOpener) {
   return TypeResolution(dc, {}, TypeResolutionStage::Structural, options,
-                        unboundTyOpener, placeholderHandler, packElementOpener);
+                        unboundTyOpener, placeholderHandler, packElementOpener,
+                        /*requirementOpener*/ nullptr);
 }
 
 TypeResolution
 TypeResolution::forInterface(DeclContext *dc, TypeResolutionOptions options,
                              OpenUnboundGenericTypeFn unboundTyOpener,
                              HandlePlaceholderTypeReprFn placeholderHandler,
-                             OpenPackElementFn packElementOpener) {
+                             OpenPackElementFn packElementOpener,
+                             OpenRequirementFn requirementOpener) {
   return forInterface(dc, dc->getGenericSignatureOfContext(), options,
-                      unboundTyOpener, placeholderHandler, packElementOpener);
+                      unboundTyOpener, placeholderHandler, packElementOpener,
+                      requirementOpener);
 }
 
-TypeResolution
-TypeResolution::forInterface(DeclContext *dc, GenericSignature genericSig,
-                             TypeResolutionOptions options,
-                             OpenUnboundGenericTypeFn unboundTyOpener,
-                             HandlePlaceholderTypeReprFn placeholderHandler,
-                             OpenPackElementFn packElementOpener) {
+TypeResolution TypeResolution::forInterface(
+    DeclContext *dc, GenericSignature genericSig, TypeResolutionOptions options,
+    OpenUnboundGenericTypeFn unboundTyOpener,
+    HandlePlaceholderTypeReprFn placeholderHandler,
+    OpenPackElementFn packElementOpener, OpenRequirementFn requirementOpener) {
   return TypeResolution(dc, genericSig, TypeResolutionStage::Interface, options,
-                        unboundTyOpener, placeholderHandler, packElementOpener);
+                        unboundTyOpener, placeholderHandler, packElementOpener,
+                        requirementOpener);
 }
 
 TypeResolution TypeResolution::withOptions(TypeResolutionOptions opts) const {
   return TypeResolution(dc, genericSig, stage, opts, unboundTyOpener,
-                        placeholderHandler, packElementOpener);
+                        placeholderHandler, packElementOpener,
+                        requirementOpener);
 }
 
 TypeResolution TypeResolution::withoutPackElementOpener() const {
   return TypeResolution(dc, genericSig, stage, options, unboundTyOpener,
-                        placeholderHandler, {});
+                        placeholderHandler, {}, requirementOpener);
 }
 
 ASTContext &TypeResolution::getASTContext() const {
@@ -230,6 +235,13 @@ Type TypeResolution::resolveDependentMemberType(
     // Record the type we found.
     repr->setValue(nestedType, nullptr);
   } else {
+    // If we have a concrete equivalence to an error type, avoid diagnosing the
+    // missing member.
+    if (auto concreteBase = genericSig->getConcreteType(baseTy)) {
+      if (concreteBase->hasError())
+        return ErrorType::get(baseTy);
+    }
+
     // Resolve the base to a potential archetype.
     // Perform typo correction.
     TypoCorrectionResults corrections(repr->getNameRef(), repr->getNameLoc());
@@ -737,8 +749,7 @@ void swift::diagnoseInvalidGenericArguments(SourceLoc loc,
     }
   }
 
-  decl->diagnose(diag::kind_declname_declared_here,
-                 DescriptiveDeclKind::GenericType, decl->getName());
+  decl->diagnose(diag::decl_declared_here_with_kind, decl);
 }
 
 namespace {
@@ -809,22 +820,145 @@ namespace {
       if (!paramType->isValue())
         return true;
 
-      // Both of these generic type parameters are values, but they may not have
-      // underlying value types associated with them. This can occur when a
-      // parameter doesn't declare a value type and we're going to diagnose it
-      // later.
-      if (!paramType->getValueType() || !secondType->getValueType())
+      // If either value type has an error, we've already diagnosed the issue.
+      auto paramValueTy = paramType->getValueType();
+      auto secondValueTy = secondType->getValueType();
+      if (paramValueTy->hasError() || secondValueTy->hasError())
         return true;
 
       // Otherwise, these are both value parameters and check that both their
       // value types are the same.
-      return paramType->getValueType()->isEqual(secondType->getValueType());
+      return paramValueTy->isEqual(secondValueTy);
     }
 
     bool alwaysMismatchTypeParameters() const { return true; }
   };
 }
 
+/// Returns true on error.
+static bool resolveGenericArguments(ValueDecl *decl,
+                                    const GenericContext *genCtx,
+                                    const TypeResolution &resolution,
+                                    SILTypeResolutionContext *silContext,
+                                    DeclRefTypeRepr *repr,
+                                    SmallVectorImpl<Type> &args) {
+  auto options = resolution.getOptions();
+  auto &ctx = decl->getASTContext();
+
+  auto genericParams = genCtx->getGenericParams();
+  auto hasParameterPack = llvm::any_of(*genericParams, [](auto *paramDecl) {
+    return paramDecl->isParameterPack();
+  });
+  auto hasValueParam = llvm::any_of(*genericParams, [](auto *paramDecl) {
+    return paramDecl->isValue();
+  });
+
+  // If the type declares at least one parameter pack, allow pack expansions
+  // anywhere in the argument list. We'll use the PackMatcher to ensure that
+  // everything lines up. Otherwise, don't allow pack expansions to appear
+  // at all.
+  auto argOptions = options.withoutContext().withContext(
+      hasParameterPack
+      ? TypeResolverContext::VariadicGenericArgument
+      : TypeResolverContext::ScalarGenericArgument);
+  if (hasValueParam)
+    argOptions = argOptions.withContext(TypeResolverContext::ValueGenericArgument);
+  auto genericResolution = resolution.withOptions(argOptions);
+
+  // In SIL mode, Optional<T> interprets T as a SIL type.
+  if (options.contains(TypeResolutionFlags::SILType)) {
+    if (auto nominal = dyn_cast<NominalTypeDecl>(genCtx)) {
+      if (nominal->isOptionalDecl()) {
+        genericResolution = resolution;
+      }
+    }
+  }
+
+  auto genericArgs = repr->getGenericArgs();
+  auto loc = repr->getNameLoc().getBaseNameLoc();
+
+  // Resolve the types of the generic arguments.
+  for (auto tyR : genericArgs) {
+    // Propagate failure.
+    Type substTy = genericResolution.resolveType(tyR, silContext);
+    if (!substTy || substTy->hasError())
+      return true;
+
+    args.push_back(substTy);
+  }
+
+  // Make sure we have the right number of generic arguments.
+  if (!hasParameterPack) {
+    // For generic types without type parameter packs, we require
+    // the number of declared generic parameters match the number of
+    // arguments.
+    if (genericArgs.size() != genericParams->size()) {
+      if (!options.contains(TypeResolutionFlags::SilenceErrors)) {
+        diagnoseInvalidGenericArguments(
+            loc, decl, genericArgs.size(), genericParams->size(),
+            /*hasParameterPack=*/false, repr->getAngleBrackets());
+      }
+      return true;
+    }
+
+    return false;
+  }
+
+  // For generic types with type parameter packs, we only require
+  // that the number of arguments is enough to saturate the number of
+  // regular generic parameters. The parameter pack will absorb
+  // zero or arguments.
+  SmallVector<Type, 2> params;
+  for (auto paramDecl : genericParams->getParams()) {
+    auto paramType = paramDecl->getDeclaredInterfaceType();
+    params.push_back(paramDecl->isParameterPack()
+                     ? PackExpansionType::get(paramType, paramType)
+                     : paramType);
+  }
+
+  PackMatcher matcher(params, args, ctx);
+  if (matcher.match() || matcher.pairs.size() != params.size()) {
+    if (!options.contains(TypeResolutionFlags::SilenceErrors)) {
+      diagnoseInvalidGenericArguments(
+          loc, decl, genericArgs.size(), genericParams->size(),
+          /*hasParameterPack=*/true, repr->getAngleBrackets());
+    }
+    return true;
+  }
+
+  args.clear();
+  for (unsigned i : indices(params)) {
+    auto found = std::find_if(matcher.pairs.begin(),
+                              matcher.pairs.end(),
+                              [&](const MatchedPair &pair) -> bool {
+                                return pair.lhsIdx == i;
+                              });
+    assert(found != matcher.pairs.end());
+
+    auto arg = found->rhs;
+
+    // PackMatcher will always produce a PackExpansionType as the
+    // arg for a pack parameter, if necessary by wrapping a PackType
+    // in one.  (It's a weird representation.)  Look for that pattern
+    // and unwrap the pack.  Otherwise, we must have matched with a
+    // single component which happened to be an expansion; wrap that
+    // in a PackType.  In either case, we always want arg to end up
+    // a PackType.
+    if (auto *expansionType = arg->getAs<PackExpansionType>()) {
+      auto pattern = expansionType->getPatternType();
+      if (auto pack = pattern->getAs<PackType>()) {
+        arg = pack;
+      } else {
+        arg = PackType::get(ctx, {expansionType});
+      }
+    }
+
+    args.push_back(arg);
+  }
+
+  return false;
+}
+
 /// Apply generic arguments to the given type.
 ///
 /// If the type is itself not generic, this does nothing.
@@ -968,16 +1102,8 @@ static Type applyGenericArguments(Type type,
     }
     
     // Try to form a substitution map.
-    auto subs = SubstitutionMap::get(bug->getGenericSignature(),
-                                     args,
-                                     [&](CanType dependentType,
-                                         Type conformingReplacementType,
-                                         ProtocolDecl *conformedProtocol)
-                                     -> ProtocolConformanceRef {
-                                       // no generic builtins have conformance
-                                       // requirements yet.
-                                       llvm_unreachable("not implemented yet");
-                                     });
+    auto subs = SubstitutionMap::get(bug->getGenericSignature(), args,
+                                     LookUpConformanceInModule());
                                      
     auto bound = bug->getBound(subs);
     
@@ -1011,112 +1137,10 @@ static Type applyGenericArguments(Type type,
   auto *unboundType = type->castTo<UnboundGenericType>();
   auto *decl = unboundType->getDecl();
 
-  auto genericParams = decl->getGenericParams();
-  auto hasParameterPack = llvm::any_of(*genericParams, [](auto *paramDecl) {
-    return paramDecl->isParameterPack();
-  });
-  auto hasValueParam = llvm::any_of(*genericParams, [](auto *paramDecl) {
-    return paramDecl->isValue();
-  });
-
-  // If the type declares at least one parameter pack, allow pack expansions
-  // anywhere in the argument list. We'll use the PackMatcher to ensure that
-  // everything lines up. Otherwise, don't allow pack expansions to appear
-  // at all.
-  auto argOptions = options.withoutContext().withContext(
-      hasParameterPack
-      ? TypeResolverContext::VariadicGenericArgument
-      : TypeResolverContext::ScalarGenericArgument);
-  if (hasValueParam)
-    argOptions = argOptions.withContext(TypeResolverContext::ValueGenericArgument);
-  auto genericResolution = resolution.withOptions(argOptions);
-
-  // In SIL mode, Optional<T> interprets T as a SIL type.
-  if (options.contains(TypeResolutionFlags::SILType)) {
-    if (auto nominal = dyn_cast<NominalTypeDecl>(decl)) {
-      if (nominal->isOptionalDecl()) {
-        genericResolution = resolution;
-      }
-    }
-  }
-
   // Resolve the types of the generic arguments.
   SmallVector<Type, 2> args;
-  for (auto tyR : genericArgs) {
-    // Propagate failure.
-    Type substTy = genericResolution.resolveType(tyR, silContext);
-    if (!substTy || substTy->hasError())
-      return ErrorType::get(ctx);
-
-    args.push_back(substTy);
-  }
-
-  // Make sure we have the right number of generic arguments.
-  if (!hasParameterPack) {
-    // For generic types without type parameter packs, we require
-    // the number of declared generic parameters match the number of
-    // arguments.
-    if (genericArgs.size() != genericParams->size()) {
-      if (!options.contains(TypeResolutionFlags::SilenceErrors)) {
-        diagnoseInvalidGenericArguments(
-            loc, decl, genericArgs.size(), genericParams->size(),
-            /*hasParameterPack=*/false, repr->getAngleBrackets());
-      }
-      return ErrorType::get(ctx);
-    }
-  } else {
-    // For generic types with type parameter packs, we only require
-    // that the number of arguments is enough to saturate the number of
-    // regular generic parameters. The parameter pack will absorb
-    // zero or arguments.
-    SmallVector<Type, 2> params;
-    for (auto paramDecl : genericParams->getParams()) {
-      auto paramType = paramDecl->getDeclaredInterfaceType();
-      params.push_back(paramDecl->isParameterPack()
-                       ? PackExpansionType::get(paramType, paramType)
-                       : paramType);
-    }
-
-    PackMatcher matcher(params, args, ctx);
-    if (matcher.match() || matcher.pairs.size() != params.size()) {
-      if (!options.contains(TypeResolutionFlags::SilenceErrors)) {
-        diagnoseInvalidGenericArguments(
-            loc, decl, genericArgs.size(), genericParams->size(),
-            /*hasParameterPack=*/true, repr->getAngleBrackets());
-      }
-      return ErrorType::get(ctx);
-    }
-
-    args.clear();
-    for (unsigned i : indices(params)) {
-      auto found = std::find_if(matcher.pairs.begin(),
-                                matcher.pairs.end(),
-                                [&](const MatchedPair &pair) -> bool {
-                                  return pair.lhsIdx == i;
-                                });
-      assert(found != matcher.pairs.end());
-
-      auto arg = found->rhs;
-
-      // PackMatcher will always produce a PackExpansionType as the
-      // arg for a pack parameter, if necessary by wrapping a PackType
-      // in one.  (It's a weird representation.)  Look for that pattern
-      // and unwrap the pack.  Otherwise, we must have matched with a
-      // single component which happened to be an expansion; wrap that
-      // in a PackType.  In either case, we always want arg to end up
-      // a PackType.
-      if (auto *expansionType = arg->getAs<PackExpansionType>()) {
-        auto pattern = expansionType->getPatternType();
-        if (auto pack = pattern->getAs<PackType>()) {
-          arg = pack;
-        } else {
-          arg = PackType::get(ctx, {expansionType});
-        }
-      }
-
-      args.push_back(arg);
-    }
-  }
+  if (resolveGenericArguments(decl, decl, resolution, silContext, repr, args))
+    return ErrorType::get(ctx);
 
   // Construct the substituted type.
   const auto result = resolution.applyUnboundGenericArguments(
@@ -1136,6 +1160,7 @@ static Type applyGenericArguments(Type type,
   if (auto clangDecl = decl->getClangDecl()) {
     if (auto classTemplateDecl =
             dyn_cast<clang::ClassTemplateDecl>(clangDecl)) {
+      // FIXME: Why does this resolve the types twice?
       SmallVector<Type, 2> typesOfGenericArgs;
       for (auto typeRepr : genericArgs) {
         typesOfGenericArgs.push_back(resolution.resolveType(typeRepr));
@@ -1195,6 +1220,7 @@ Type TypeResolution::applyUnboundGenericArguments(
   // or unbound generics, let's skip the check here, and let the solver
   // do it when missing types are deduced.
   bool skipRequirementsCheck = false;
+  bool hasTypeVariables = false;
   if (options.contains(TypeResolutionFlags::SILType)) {
     if (auto nominal = dyn_cast<NominalTypeDecl>(decl)) {
       if (nominal->isOptionalDecl()) {
@@ -1225,7 +1251,7 @@ Type TypeResolution::applyUnboundGenericArguments(
       subs = parentTy->getContextSubstitutions(decl->getDeclContext());
     }
 
-    skipRequirementsCheck |= parentTy->hasTypeVariable();
+    hasTypeVariables |= parentTy->hasTypeVariable();
 
   // Fill in substitutions for outer generic parameters if we have a local
   // type in generic context. This isn't actually supported all the way,
@@ -1253,56 +1279,59 @@ Type TypeResolution::applyUnboundGenericArguments(
     // Enter the substitution.
     subs[paramTy] = substTy;
 
-    skipRequirementsCheck |=
-        substTy->hasTypeVariable() || substTy->hasUnboundGenericType();
+    hasTypeVariables |= substTy->hasTypeVariable();
+    skipRequirementsCheck |= substTy->hasUnboundGenericType();
   }
 
+  const auto substitutions = [&](SubstitutableType *type) -> Type {
+    auto result = QueryTypeSubstitutionMap{subs}(type);
+    if (result->hasTypeParameter()) {
+      if (const auto contextSig = getGenericSignature()) {
+        auto *genericEnv = contextSig.getGenericEnvironment();
+        // FIXME: This should just use mapTypeIntoContext(), but we can't yet
+        // because we sometimes have type parameters here that are invalid for
+        // our generic signature. This can happen if the type parameter was
+        // found via unqualified lookup, but the current context's
+        // generic signature failed to build because of circularity or
+        // completion failure.
+        return result.subst(QueryInterfaceTypeSubstitutions{genericEnv},
+                            LookUpConformanceInModule(),
+                            SubstFlags::PreservePackExpansionLevel);
+      }
+    }
+    return result;
+  };
+
   // Check the generic arguments against the requirements of the declaration's
   // generic signature.
   if (!skipRequirementsCheck && getStage() == TypeResolutionStage::Interface) {
-    // Check the generic arguments against the requirements of the declaration's
-    // generic signature.
+    if (hasTypeVariables) {
+      ASSERT(requirementOpener && "Must have requirement opener for type vars");
+      requirementOpener(decl, substitutions);
+    } else {
+      SourceLoc noteLoc = decl->getLoc();
+      if (noteLoc.isInvalid())
+        noteLoc = loc;
 
-    SourceLoc noteLoc = decl->getLoc();
-    if (noteLoc.isInvalid())
-      noteLoc = loc;
+      auto genericSig = decl->getGenericSignature();
 
-    auto genericSig = decl->getGenericSignature();
-    const auto substitutions = [&](SubstitutableType *type) -> Type {
-      auto result = QueryTypeSubstitutionMap{subs}(type);
-      if (result->hasTypeParameter()) {
-        if (const auto contextSig = getGenericSignature()) {
-          auto *genericEnv = contextSig.getGenericEnvironment();
-          // FIXME: This should just use mapTypeIntoContext(), but we can't yet
-          // because we sometimes have type parameters here that are invalid for
-          // our generic signature. This can happen if the type parameter was
-          // found via unqualified lookup, but the current context's
-          // generic signature failed to build because of circularity or
-          // completion failure.
-          return result.subst(QueryInterfaceTypeSubstitutions{genericEnv},
-                              LookUpConformanceInModule(),
-                              SubstFlags::PreservePackExpansionLevel);
+      const auto result = TypeChecker::checkGenericArgumentsForDiagnostics(
+          genericSig, substitutions);
+      switch (result.getKind()) {
+      case CheckRequirementsResult::RequirementFailure:
+        if (loc.isValid()) {
+          TypeChecker::diagnoseRequirementFailure(
+              result.getRequirementFailureInfo(), loc, noteLoc,
+              UnboundGenericType::get(decl, parentTy, ctx),
+              genericSig.getGenericParams(), substitutions);
         }
-      }
-      return result;
-    };
 
-    const auto result = TypeChecker::checkGenericArgumentsForDiagnostics(
-        genericSig, substitutions);
-    switch (result.getKind()) {
-    case CheckRequirementsResult::RequirementFailure:
-      if (loc.isValid()) {
-        TypeChecker::diagnoseRequirementFailure(
-            result.getRequirementFailureInfo(), loc, noteLoc,
-            UnboundGenericType::get(decl, parentTy, ctx),
-            genericSig.getGenericParams(), substitutions);
+        LLVM_FALLTHROUGH;
+      case CheckRequirementsResult::SubstitutionFailure:
+        return ErrorType::get(ctx);
+      case CheckRequirementsResult::Success:
+        break;
       }
-
-      LLVM_FALLTHROUGH;
-    case CheckRequirementsResult::SubstitutionFailure:
-      return ErrorType::get(ctx);
-    case CheckRequirementsResult::Success:
-      break;
     }
   }
 
@@ -1346,9 +1375,7 @@ static void diagnoseUnboundGenericType(Type ty, SourceLoc loc) {
         diag.fixItInsertAfter(loc, genericArgsToAdd);
     }
 
-    decl->diagnose(diag::kind_declname_declared_here,
-                   DescriptiveDeclKind::GenericType,
-                   decl->getName());
+    decl->diagnose(diag::decl_declared_here_with_kind, decl);
   } else {
     ty.findIf([&](Type t) -> bool {
       if (t->is<UnboundGenericType>()) {
@@ -1468,7 +1495,7 @@ static Type diagnoseUnknownType(const TypeResolution &resolution,
   if (parentType.isNull()) {
     // Tailored diagnostic for custom attributes.
     if (resolution.getOptions().is(TypeResolverContext::CustomAttr)) {
-      diags.diagnose(repr->getNameLoc(), diag::unknown_attribute,
+      diags.diagnose(repr->getNameLoc(), diag::unknown_attr_name,
                      repr->getNameRef().getBaseIdentifier().str());
 
       return ErrorType::get(ctx);
@@ -1783,7 +1810,8 @@ resolveUnqualifiedIdentTypeRepr(const TypeResolution &resolution,
   // If the look up did not yield any results, try again but allow members from
   // modules that are not directly imported to be accessible.
   bool didIgnoreMissingImports = false;
-  if (!globals && ctx.LangOpts.hasFeature(Feature::MemberImportVisibility)) {
+  if (!globals && ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                                          /*allowMigration=*/true)) {
     lookupOptions |= NameLookupFlags::IgnoreMissingImports;
     globals = TypeChecker::lookupUnqualifiedType(DC, id, repr->getLoc(),
                                                  lookupOptions);
@@ -2046,8 +2074,8 @@ static Type resolveQualifiedIdentTypeRepr(const TypeResolution &resolution,
         DC, parentTy, repr->getNameRef(), repr->getLoc(), lookupOptions);
 
     // If no members were found, try ignoring missing imports.
-    if (!memberTypes &&
-        ctx.LangOpts.hasFeature(Feature::MemberImportVisibility)) {
+    if (!memberTypes && ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                                                /*allowMigration=*/true)) {
       lookupOptions |= NameLookupFlags::IgnoreMissingImports;
       memberTypes = TypeChecker::lookupMemberType(
           DC, parentTy, repr->getNameRef(), repr->getLoc(), lookupOptions);
@@ -2327,6 +2355,8 @@ namespace {
                                           TypeResolutionOptions options);
     NeverNullType resolveSendingTypeRepr(SendingTypeRepr *repr,
                                          TypeResolutionOptions options);
+    NeverNullType resolveCallerIsolatedTypeRepr(CallerIsolatedTypeRepr *repr,
+                                                TypeResolutionOptions options);
     NeverNullType
     resolveCompileTimeLiteralTypeRepr(CompileTimeLiteralTypeRepr *repr,
                                       TypeResolutionOptions options);
@@ -2416,6 +2446,11 @@ namespace {
   class TypeAttrSet {
     const ASTContext &ctx;
 
+    /// FIXME:
+    ///  `nonisolated(nonsending)` is modeled as a separate `TypeRepr`, but
+    ///  needs to be considered together with subsequent attributes.
+    CallerIsolatedTypeRepr *nonisolatedNonsendingAttr;
+
     llvm::TinyPtrVector<CustomAttr*> customAttrs;
     EnumMap<TypeAttrKind, TypeAttribute *> typeAttrs;
 
@@ -2427,7 +2462,9 @@ namespace {
 #endif
 
   public:
-    TypeAttrSet(const ASTContext &ctx) : ctx(ctx) {}
+    TypeAttrSet(const ASTContext &ctx,
+                CallerIsolatedTypeRepr *nonisolatedNonsendingAttr = nullptr)
+        : ctx(ctx), nonisolatedNonsendingAttr(nonisolatedNonsendingAttr) {}
 
     TypeAttrSet(const TypeAttrSet &) = delete;
     TypeAttrSet &operator=(const TypeAttrSet &) = delete;
@@ -2446,6 +2483,10 @@ namespace {
     /// will be diagnosed.
     void accumulate(ArrayRef<TypeOrCustomAttr> attrs);
 
+    CallerIsolatedTypeRepr *getNonisolatedNonsendingAttr() const {
+      return nonisolatedNonsendingAttr;
+    }
+
     /// Return all of the custom attributes.
     ArrayRef<CustomAttr*> getCustomAttrs() const {
       return customAttrs;
@@ -2545,31 +2586,39 @@ namespace {
   }
 
   template <class AttrClass>
-  AttrClass *getWithoutClaiming(TypeAttrSet *attrs) {
+  std::enable_if_t<std::is_base_of_v<TypeAttribute, AttrClass>, AttrClass *>
+  getWithoutClaiming(TypeAttrSet *attrs) {
     return (attrs ? getWithoutClaiming<AttrClass>(*attrs) : nullptr);
   }
+
+  template <class AttrClass>
+  std::enable_if_t<std::is_same_v<AttrClass, CallerIsolatedTypeRepr>,
+                   CallerIsolatedTypeRepr *>
+  getWithoutClaiming(TypeAttrSet *attrs) {
+    return attrs ? attrs->getNonisolatedNonsendingAttr() : nullptr;
+  }
 } // end anonymous namespace
 
 Type TypeResolution::resolveContextualType(
     TypeRepr *TyR, DeclContext *dc, TypeResolutionOptions opts,
     OpenUnboundGenericTypeFn unboundTyOpener,
     HandlePlaceholderTypeReprFn placeholderHandler,
-    OpenPackElementFn packElementOpener,
+    OpenPackElementFn packElementOpener, OpenRequirementFn requirementOpener,
     SILTypeResolutionContext *silContext) {
-  return resolveContextualType(TyR, dc, dc->getGenericSignatureOfContext(),
-                               opts, unboundTyOpener, placeholderHandler,
-                               packElementOpener, silContext);
+  return resolveContextualType(
+      TyR, dc, dc->getGenericSignatureOfContext(), opts, unboundTyOpener,
+      placeholderHandler, packElementOpener, requirementOpener, silContext);
 }
 
 Type TypeResolution::resolveContextualType(
     TypeRepr *TyR, DeclContext *dc, GenericSignature genericSig,
     TypeResolutionOptions opts, OpenUnboundGenericTypeFn unboundTyOpener,
     HandlePlaceholderTypeReprFn placeholderHandler,
-    OpenPackElementFn packElementOpener,
+    OpenPackElementFn packElementOpener, OpenRequirementFn requirementOpener,
     SILTypeResolutionContext *silContext) {
   const auto resolution = TypeResolution::forInterface(
       dc, genericSig, opts, unboundTyOpener, placeholderHandler,
-      packElementOpener);
+      packElementOpener, requirementOpener);
   const auto ty = resolution.resolveType(TyR, silContext);
 
   return GenericEnvironment::mapTypeIntoContext(
@@ -2619,10 +2668,12 @@ static Type evaluateTypeResolution(const TypeResolution *resolution,
       TypeResolver(*resolution, silContext)
           .resolveType(TyR, resolution->getOptions());
 
-  // If we resolved down to an error, make sure to mark the typeRepr as invalid
-  // so we don't produce a redundant diagnostic.
+  // If we resolved down to an error, and we haven't silenced diagnostics, make
+  // sure to mark the typeRepr as invalid so we don't produce a redundant
+  // diagnostic.
   if (result->hasError()) {
-    TyR->setInvalid();
+    if (!options.contains(TypeResolutionFlags::SilenceErrors))
+      TyR->setInvalid();
     return result;
   }
 
@@ -2683,7 +2734,7 @@ bool swift::diagnoseMissingOwnership(ParamSpecifier ownership,
              resolution.getGenericSignature().getGenericEnvironment(),
              ty);
 
-  if (ty->hasError() || !ty->isNoncopyable())
+  if (ty->hasError() || ty->isCopyable())
     return false; // copyable types do not need ownership
 
   if (ownership != ParamSpecifier::Default)
@@ -2733,7 +2784,8 @@ NeverNullType TypeResolver::resolveType(TypeRepr *repr,
       !isa<SpecifierTypeRepr>(repr) && !isa<TupleTypeRepr>(repr) &&
       !isa<AttributedTypeRepr>(repr) && !isa<FunctionTypeRepr>(repr) &&
       !isa<DeclRefTypeRepr>(repr) && !isa<PackExpansionTypeRepr>(repr) &&
-      !isa<ImplicitlyUnwrappedOptionalTypeRepr>(repr)) {
+      !isa<ImplicitlyUnwrappedOptionalTypeRepr>(repr) &&
+      !isa<CallerIsolatedTypeRepr>(repr)) {
     options.setContext(std::nullopt);
   }
 
@@ -2745,7 +2797,6 @@ NeverNullType TypeResolver::resolveType(TypeRepr *repr,
 
   switch (repr->getKind()) {
   case TypeReprKind::Error:
-    cast<ErrorTypeRepr>(repr)->dischargeDiagnostic(getASTContext());
     return ErrorType::get(getASTContext());
 
   case TypeReprKind::Attributed:
@@ -2756,6 +2807,9 @@ NeverNullType TypeResolver::resolveType(TypeRepr *repr,
     return resolveIsolatedTypeRepr(cast<IsolatedTypeRepr>(repr), options);
   case TypeReprKind::Sending:
     return resolveSendingTypeRepr(cast<SendingTypeRepr>(repr), options);
+  case TypeReprKind::CallerIsolated:
+    return resolveCallerIsolatedTypeRepr(cast<CallerIsolatedTypeRepr>(repr),
+                                         options);
   case TypeReprKind::CompileTimeLiteral:
       return resolveCompileTimeLiteralTypeRepr(cast<CompileTimeLiteralTypeRepr>(repr),
                                                options);
@@ -3030,7 +3084,7 @@ TypeResolver::resolveOpenedExistentialArchetype(
         [&](SubstitutableType *type) -> Type {
           return env->getGenericSignature().getGenericParams().back();
         },
-        MakeAbstractConformanceForGenericType());
+        LookUpConformanceInModule());
 
     archetypeType = env->mapTypeIntoContext(interfaceType);
     ASSERT(archetypeType->is<ExistentialArchetypeType>());
@@ -3148,6 +3202,7 @@ TypeAttrKind TypeAttrSet::getRepresentative(TypeAttrKind kind) {
   case TypeAttrKind::InoutAliasable:
   case TypeAttrKind::Owned:
   case TypeAttrKind::Guaranteed:
+  case TypeAttrKind::GuaranteedAddress:
   case TypeAttrKind::PackOwned:
   case TypeAttrKind::PackGuaranteed:
   case TypeAttrKind::PackInout:
@@ -3203,7 +3258,7 @@ void TypeAttrSet::accumulate(ArrayRef<TypeOrCustomAttr> attrs) {
       continue;
     }
 
-    auto typeAttr = attr.get<TypeAttribute*>();
+    auto typeAttr = cast<TypeAttribute *>(attr);
     auto representativeKind = getRepresentative(typeAttr->getKind());
 
     // Try to insert the attribute in the set under its representative
@@ -3240,9 +3295,8 @@ void TypeAttrSet::diagnoseConflict(TypeAttrKind representativeKind,
   }
 
   // Generic conflict diagnostic
-  diagnose(secondAttr->getStartLoc(), diag::mutually_exclusive_attr_names,
-           secondAttr->getAttrName(), firstAttr->getAttrName(),
-           /*modifier*/ false);
+  diagnose(secondAttr->getStartLoc(), diag::mutually_exclusive_type_attrs,
+           secondAttr, firstAttr);
 }
 
 void TypeAttrSet::diagnoseUnclaimed(const TypeResolution &resolution,
@@ -3297,7 +3351,7 @@ void TypeAttrSet::diagnoseUnclaimed(CustomAttr *attr,
     typeName = attr->getType().getString();
   }
 
-  diagnose(attr->getLocation(), diag::unknown_attribute, typeName);
+  diagnose(attr->getLocation(), diag::unknown_attr_name, typeName);
 }
 
 static bool isFunctionAttribute(TypeAttrKind attrKind) {
@@ -3333,7 +3387,7 @@ void TypeAttrSet::diagnoseUnclaimed(TypeAttribute *attr,
   // Use a special diagnostic for SIL attributes.
   if (!(options & TypeResolutionFlags::SILType) &&
       TypeAttribute::isSilOnly(attr->getKind())) {
-    diagnose(attr->getStartLoc(), diag::unknown_attribute, attr->getAttrName());
+    diagnose(attr->getStartLoc(), diag::unknown_type_attr, attr);
     return;
   }
 
@@ -3354,8 +3408,7 @@ void TypeAttrSet::diagnoseUnclaimed(TypeAttribute *attr,
     }
 
     auto diagnostic = diagnose(attr->getStartLoc(),
-                               diag::attribute_requires_function_type,
-                               attr->getAttrName());
+                               diag::type_attr_requires_function_type, attr);
     if (isa<EscapingTypeAttr>(attr))
       diagnostic.fixItRemove(attr->getSourceRange());
     return;
@@ -3502,12 +3555,11 @@ TypeResolver::resolveAttributedType(TypeRepr *repr, TypeResolutionOptions option
     if (!options.is(TypeResolverContext::Inherited) ||
         getDeclContext()->getSelfProtocolDecl()) {
       diagnoseInvalid(repr, attr->getAtLoc(),
-                      diag::typeattr_not_inheritance_clause,
-                      attr->getAttrName());
+                      diag::typeattr_not_inheritance_clause, attr);
       ty = ErrorType::get(getASTContext());
     } else if (!ty->isConstraintType()) {
-      diagnoseInvalid(repr, attr->getAtLoc(),
-                      diag::typeattr_not_existential, attr->getAttrName(), ty);
+      diagnoseInvalid(repr, attr->getAtLoc(), diag::typeattr_not_existential,
+                      attr, ty);
       ty = ErrorType::get(getASTContext());
     }
 
@@ -3535,7 +3587,8 @@ TypeResolver::resolveAttributedType(TypeRepr *repr, TypeResolutionOptions option
     bool isInInheritanceClause = options.is(TypeResolverContext::Inherited);
     if (!isInInheritanceClause || !extension) {
       diagnoseInvalid(repr, retroactiveAttr->getAtLoc(),
-                      diag::retroactive_not_in_extension_inheritance_clause)
+                      diag::typeattr_not_extension_inheritance_clause,
+                      retroactiveAttr)
           .fixItRemove(retroactiveAttr->getSourceRange());
       ty = ErrorType::get(getASTContext());
     }
@@ -3642,8 +3695,7 @@ TypeResolver::resolveAttributedType(TypeRepr *repr, TypeResolutionOptions option
       diagnose(
           noDerivativeAttr->getAtLoc(),
           diag::differentiable_programming_attr_used_without_required_module,
-          TypeAttribute::getAttrName(TypeAttrKind::NoDerivative),
-          getASTContext().Id_Differentiation);
+          noDerivativeAttr, getASTContext().Id_Differentiation);
     } else if (!isNoDerivativeAllowed) {
       bool isVariadicFunctionParam =
           options.is(TypeResolverContext::VariadicFunctionInput) &&
@@ -3656,10 +3708,8 @@ TypeResolver::resolveAttributedType(TypeRepr *repr, TypeResolutionOptions option
     }
   }
 
-  if (getASTContext().LangOpts.hasFeature(Feature::LayoutPrespecialization)) {
-    (void) claim<NoMetadataTypeAttr>(attrs);
-    // TODO: add proper validation
-  }
+  (void)claim<NoMetadataTypeAttr>(attrs);
+  // TODO: add proper validation
 
   // There are a bunch of attributes in SIL that are essentially new
   // type constructors.  Some of these are allowed even in AST positions;
@@ -3976,25 +4026,12 @@ TypeResolver::resolveASTFunctionTypeParams(TupleTypeRepr *inputRepr,
   return elements;
 }
 
+/// Implement the special @_opaqueReturnTypeOf attribute syntax in
+/// module interface files.
 NeverNullType
 TypeResolver::resolveOpaqueReturnType(TypeRepr *repr, StringRef mangledName,
                                       unsigned ordinal,
                                       TypeResolutionOptions options) {
-  // The type representation should be an unqualified identifier. We don't
-  // really use the identifier for anything, but we do resolve any generic
-  // arguments to instantiate the possibly-generic opaque type.
-  SmallVector<Type, 4> TypeArgsBuf;
-  if (auto *unqualIdentRepr = dyn_cast<UnqualifiedIdentTypeRepr>(repr)) {
-    for (auto argRepr : unqualIdentRepr->getGenericArgs()) {
-      auto argTy = resolveType(argRepr, options);
-      // If we cannot resolve the generic parameter, propagate the error out.
-      if (argTy->hasError()) {
-        return ErrorType::get(getASTContext());
-      }
-      TypeArgsBuf.push_back(argTy);
-    }
-  }
-
   // Use type reconstruction to summon the opaque type decl.
   Demangler demangle;
   auto definingDeclNode = demangle.demangleSymbol(mangledName);
@@ -4008,14 +4045,97 @@ TypeResolver::resolveOpaqueReturnType(TypeRepr *repr, StringRef mangledName,
   auto opaqueNode =
     builder.getNodeFactory().createNode(Node::Kind::OpaqueReturnTypeOf);
   opaqueNode->addChild(definingDeclNode, builder.getNodeFactory());
-  
-  auto TypeArgs = ArrayRef<Type>(TypeArgsBuf);
-  auto ty = builder.resolveOpaqueType(opaqueNode, TypeArgs, ordinal);
-  if (!ty || ty->hasError()) {
+  auto *opaqueDecl = builder.resolveOpaqueTypeDecl(opaqueNode);
+  if (!opaqueDecl) {
     diagnose(repr->getLoc(), diag::no_opaque_return_type_of);
     return ErrorType::get(getASTContext());
   }
-  return ty;
+
+  auto *ownerDecl = opaqueDecl->getNamingDecl();
+  auto genericSig = ownerDecl->getInnermostDeclContext()
+    ->getGenericSignatureOfContext();
+
+  SubstitutionMap subs;
+  if (genericSig) {
+    SmallVector<Type, 2> args;
+
+    // The type representation should either be a single identifier, or a
+    // series of member references. We don't use the identifiers for
+    // anything, but we do resolve the generic arguments at each level
+    // to instantiate the possibly-generic opaque type.
+    if (isa<UnqualifiedIdentTypeRepr>(repr) &&
+        !genericSig->hasParameterPack()) {
+      // When there are no parameter packs and we just have a single
+      // unqualified identifier, we fall back to the legacy behavior,
+      // which collects the generic arguments for all levels of nesting
+      // in a flat list.
+      //
+      // This matches the old behavior of the ASTPrinter.
+      auto *unqualIdentRepr = cast<UnqualifiedIdentTypeRepr>(repr);
+
+      for (auto argRepr : unqualIdentRepr->getGenericArgs()) {
+        auto argTy = resolveType(argRepr, options);
+        // If we cannot resolve the generic parameter, propagate the error out.
+        if (argTy->hasError()) {
+          return ErrorType::get(getASTContext());
+        }
+        args.push_back(argTy);
+      }
+
+      if (args.size() != genericSig.getGenericParams().size()) {
+        diagnose(repr->getLoc(), diag::no_opaque_return_type_of);
+        return ErrorType::get(getASTContext());
+      }
+    } else {
+      // Correct handling of nested types. We interpret a qualified
+      // TypeRepr with a generic argument list at each level, like
+      // __<OuterArgs, ...>.__<InnerArgs, ...>.
+      SmallVector<SmallVector<Type, 2>, 2> nestedArgs;
+
+      auto *dc = ownerDecl->getInnermostDeclContext();
+      while (!dc->isModuleScopeContext()) {
+        if (dc->isInnermostContextGeneric()) {
+          if (repr == nullptr || !isa<DeclRefTypeRepr>(repr)) {
+            diagnose(repr->getLoc(), diag::no_opaque_return_type_of);
+            return ErrorType::get(getASTContext());
+          }
+
+          auto *identRepr = cast<DeclRefTypeRepr>(repr);
+          nestedArgs.emplace_back();
+
+          auto *decl = dyn_cast<ValueDecl>(dc->getAsDecl());
+          if (decl == nullptr)
+            decl = dc->getSelfNominalTypeDecl();
+          ASSERT(decl);
+
+          resolveGenericArguments(decl,
+                                  decl->getAsGenericContext(),
+                                  resolution,
+                                  silContext,
+                                  identRepr,
+                                  nestedArgs.back());
+          repr = identRepr->getBase();
+        }
+
+        dc = dc->getParent();
+      }
+
+      for (auto &subArgs : llvm::reverse(nestedArgs)) {
+        args.append(subArgs.begin(), subArgs.end());
+      }
+    }
+
+    subs = SubstitutionMap::get(genericSig, args,
+                                LookUpConformanceInModule());
+  }
+
+  if (ordinal >= opaqueDecl->getOpaqueGenericParams().size()) {
+    diagnose(repr->getLoc(), diag::no_opaque_return_type_of);
+    return ErrorType::get(getASTContext());
+  }
+
+  Type interfaceType = opaqueDecl->getOpaqueGenericParams()[ordinal];
+  return OpaqueTypeArchetypeType::get(opaqueDecl, interfaceType, subs);
 }
 
 NeverNullType TypeResolver::resolveASTFunctionType(
@@ -4083,7 +4203,7 @@ NeverNullType TypeResolver::resolveASTFunctionType(
       diagnoseInvalid(
           repr, diffAttr->getAtLoc(),
           diag::differentiable_programming_attr_used_without_required_module,
-          diffAttr->getAttrName(), ctx.Id_Differentiation);
+          diffAttr, ctx.Id_Differentiation);
     }
   }
 
@@ -4201,10 +4321,11 @@ NeverNullType TypeResolver::resolveASTFunctionType(
     }
   }
 
-  if (auto executionAttr = claim<ExecutionTypeAttr>(attrs)) {
+  auto checkExecutionBehaviorAttribute = [&](TypeAttribute *attr) {
     if (!repr->isAsync()) {
-      diagnoseInvalid(repr, executionAttr->getAtLoc(),
-                      diag::attr_execution_type_attr_only_on_async);
+      diagnoseInvalid(repr, attr->getAttrLoc(),
+                      diag::execution_behavior_type_attr_only_on_async,
+                      attr->getAttrName());
     }
 
     switch (isolation.getKind()) {
@@ -4213,41 +4334,55 @@ NeverNullType TypeResolver::resolveASTFunctionType(
 
     case FunctionTypeIsolation::Kind::GlobalActor:
       diagnoseInvalid(
-          repr, executionAttr->getAtLoc(),
-          diag::attr_execution_type_attr_incompatible_with_global_isolation,
-          isolation.getGlobalActorType());
+          repr, attr->getAttrLoc(),
+          diag::execution_behavior_type_attr_incompatible_with_global_isolation,
+          attr->getAttrName(), isolation.getGlobalActorType());
       break;
 
     case FunctionTypeIsolation::Kind::Parameter:
       diagnoseInvalid(
-          repr, executionAttr->getAtLoc(),
-          diag::attr_execution_type_attr_incompatible_with_isolated_param);
+          repr, attr->getAttrLoc(),
+          diag::execution_behavior_type_attr_incompatible_with_isolated_param,
+          attr->getAttrName());
       break;
 
     case FunctionTypeIsolation::Kind::Erased:
       diagnoseInvalid(
-          repr, executionAttr->getAtLoc(),
-          diag::attr_execution_type_attr_incompatible_with_isolated_any);
+          repr, attr->getAttrLoc(),
+          diag::execution_behavior_type_attr_incompatible_with_isolated_any,
+          attr->getAttrName());
       break;
 
-    case FunctionTypeIsolation::Kind::NonIsolatedCaller:
-      llvm_unreachable("cannot happen because multiple @execution attributes "
-                       "aren't allowed.");
+    case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
+      llvm_unreachable(
+          "cannot happen because multiple execution behavior attributes "
+          "aren't allowed.");
     }
+  };
 
-    if (!repr->isInvalid()) {
-      switch (executionAttr->getBehavior()) {
-      case ExecutionKind::Concurrent:
-        isolation = FunctionTypeIsolation::forNonIsolated();
-        break;
-      case ExecutionKind::Caller:
-        isolation = FunctionTypeIsolation::forNonIsolatedCaller();
-        break;
-      }
-    }
-  } else {
-    if (ctx.LangOpts.getFeatureState(Feature::AsyncCallerExecution)
-            .isEnabledForAdoption()) {
+  if (auto concurrentAttr = claim<ConcurrentTypeAttr>(attrs)) {
+    if (auto *nonisolatedNonsendingAttr =
+            getWithoutClaiming<CallerIsolatedTypeRepr>(attrs)) {
+      diagnoseInvalid(
+          nonisolatedNonsendingAttr, nonisolatedNonsendingAttr->getStartLoc(),
+          diag::cannot_use_nonisolated_nonsending_together_with_concurrent,
+          nonisolatedNonsendingAttr);
+    }
+
+    checkExecutionBehaviorAttribute(concurrentAttr);
+
+    if (!repr->isInvalid())
+      isolation = FunctionTypeIsolation::forNonIsolated();
+  } else if (!getWithoutClaiming<CallerIsolatedTypeRepr>(attrs)) {
+    // Infer async function type as `nonisolated(nonsending)` if there is
+    // no `@concurrent` or `nonisolated(nonsending)` attribute and isolation
+    // is nonisolated.
+    if (ctx.LangOpts.hasFeature(Feature::NonisolatedNonsendingByDefault) &&
+        repr->isAsync() && isolation.isNonIsolated()) {
+      isolation = FunctionTypeIsolation::forNonIsolatedCaller();
+    } else if (ctx.LangOpts
+                   .getFeatureState(Feature::NonisolatedNonsendingByDefault)
+                   .isEnabledForMigration()) {
       // Diagnose only in the interface stage, which is run once.
       if (inStage(TypeResolutionStage::Interface)) {
         warnAboutNewNonisolatedAsyncExecutionBehavior(ctx, repr, isolation);
@@ -4301,6 +4436,8 @@ NeverNullType TypeResolver::resolveASTFunctionType(
             thrownTy);
       }
     }
+  } else if (repr->getThrowsLoc().isValid()) {
+    diagnoseUntypedThrowsInEmbedded(getDeclContext(), repr->getThrowsLoc());
   }
 
   bool hasSendingResult =
@@ -4312,7 +4449,7 @@ NeverNullType TypeResolver::resolveASTFunctionType(
   FunctionType::ExtInfoBuilder extInfoBuilder(
       FunctionTypeRepresentation::Swift, noescape, repr->isThrowing(), thrownTy,
       diffKind, /*clangFunctionType*/ nullptr, isolation,
-      /*LifetimeDependenceInfo*/ std::nullopt, hasSendingResult);
+      /*LifetimeDependenceInfo*/ {}, hasSendingResult);
 
   const clang::Type *clangFnType = parsedClangFunctionType;
   if (shouldStoreClangType(representation) && !clangFnType)
@@ -4360,11 +4497,10 @@ NeverNullType TypeResolver::resolveSILBoxType(SILBoxTypeRepr *repr,
     auto *genericParams = repr->getGenericParams();
 
     if (genericParams) {
-      fieldResolution =
-          TypeResolution::forInterface(getDeclContext(), genericSig, options,
-                                       resolution.getUnboundTypeOpener(),
-                                       resolution.getPlaceholderHandler(),
-                                       resolution.getPackElementOpener());
+      fieldResolution = TypeResolution::forInterface(
+          getDeclContext(), genericSig, options,
+          resolution.getUnboundTypeOpener(), resolution.getPlaceholderHandler(),
+          resolution.getPackElementOpener(), resolution.getRequirementOpener());
     }
 
     SILInnerGenericContextRAII scope(silContext, genericParams);
@@ -4502,7 +4638,7 @@ NeverNullType TypeResolver::resolveSILFunctionType(FunctionTypeRepr *repr,
       diagnoseInvalid(
           repr, diffAttr->getAtLoc(),
           diag::differentiable_programming_attr_used_without_required_module,
-          diffAttr->getAttrName(), getASTContext().Id_Differentiation);
+          diffAttr, getASTContext().Id_Differentiation);
       hasError = true;
     }
   }
@@ -4533,7 +4669,7 @@ NeverNullType TypeResolver::resolveSILFunctionType(FunctionTypeRepr *repr,
   auto extInfoBuilder = SILFunctionType::ExtInfoBuilder(
       representation, pseudogeneric, noescape, sendable, async, unimplementable,
       isolation, diffKind, clangFnType,
-      /*LifetimeDependenceInfo*/ std::nullopt);
+      /*LifetimeDependenceInfo*/ {});
 
   // Resolve parameter and result types using the function's generic
   // environment.
@@ -4569,9 +4705,8 @@ NeverNullType TypeResolver::resolveSILFunctionType(FunctionTypeRepr *repr,
     if (componentTypeSig) {
       functionResolution = TypeResolution::forInterface(
           getDeclContext(), componentTypeSig, options,
-          resolution.getUnboundTypeOpener(),
-          resolution.getPlaceholderHandler(),
-          resolution.getPackElementOpener());
+          resolution.getUnboundTypeOpener(), resolution.getPlaceholderHandler(),
+          resolution.getPackElementOpener(), resolution.getRequirementOpener());
     }
 
     SILInnerGenericContextRAII innerGenericContext(silContext,
@@ -4627,11 +4762,10 @@ NeverNullType TypeResolver::resolveSILFunctionType(FunctionTypeRepr *repr,
   SubstitutionMap patternSubs;
   if (!repr->getPatternSubstitutions().empty()) {
     if (genericSig) {
-      auto resolveSILParameters =
-          TypeResolution::forInterface(getDeclContext(), genericSig, options,
-                                       resolution.getUnboundTypeOpener(),
-                                       resolution.getPlaceholderHandler(),
-                                       resolution.getPackElementOpener());
+      auto resolveSILParameters = TypeResolution::forInterface(
+          getDeclContext(), genericSig, options,
+          resolution.getUnboundTypeOpener(), resolution.getPlaceholderHandler(),
+          resolution.getPackElementOpener(), resolution.getRequirementOpener());
       patternSubs = resolveSubstitutions(repr->getPatternGenericSignature(),
                                          repr->getPatternSubstitutions(),
                                          TypeResolver{resolveSILParameters,
@@ -4873,6 +5007,8 @@ bool TypeResolver::resolveSingleSILResult(
         ERROR(ErrorUnowned, Unowned)
         NORMAL(Out, Indirect)
         NORMAL(Owned, Owned)
+        NORMAL(Guaranteed, Guaranteed)
+        NORMAL(GuaranteedAddress, GuaranteedAddress)
         NORMAL(UnownedInnerPointer, UnownedInnerPointer)
         NORMAL(Autoreleased, Autoreleased)
         NORMAL(PackOut, Pack)
@@ -5034,7 +5170,7 @@ TypeResolver::resolveDeclRefTypeRepr(DeclRefTypeRepr *repr,
       // Tailored diagnostic for custom attributes.
       if (options.is(TypeResolverContext::CustomAttr)) {
         auto &ctx = resolution.getASTContext();
-        ctx.Diags.diagnose(repr->getNameLoc(), diag::unknown_attribute,
+        ctx.Diags.diagnose(repr->getNameLoc(), diag::unknown_attr_name,
                            repr->getNameRef().getBaseIdentifier().str());
 
         return ErrorType::get(ctx);
@@ -5273,6 +5409,73 @@ TypeResolver::resolveSendingTypeRepr(SendingTypeRepr *repr,
   return resolveType(repr->getBase(), options);
 }
 
+NeverNullType
+TypeResolver::resolveCallerIsolatedTypeRepr(CallerIsolatedTypeRepr *repr,
+                                            TypeResolutionOptions options) {
+  Type type;
+  {
+    TypeAttrSet attrs(getASTContext(), repr);
+
+    auto *baseRepr = repr->getBase();
+    if (auto *attrRepr = dyn_cast<AttributedTypeRepr>(baseRepr)) {
+      baseRepr = attrs.accumulate(attrRepr);
+    }
+
+    type = resolveAttributedType(baseRepr, options, attrs);
+
+    attrs.diagnoseUnclaimed(resolution, options, type);
+  }
+
+  if (type->hasError())
+    return ErrorType::get(getASTContext());
+
+  auto *fnType = dyn_cast<AnyFunctionType>(type.getPointer());
+  if (!fnType) {
+    diagnoseInvalid(repr, repr->getStartLoc(),
+                    diag::nonisolated_nonsending_only_on_function_types, repr);
+    return ErrorType::get(getASTContext());
+  }
+
+  if (!fnType->isAsync()) {
+    diagnoseInvalid(repr, repr->getStartLoc(),
+                    diag::nonisolated_nonsending_only_on_async, repr);
+  }
+
+  switch (fnType->getIsolation().getKind()) {
+  case FunctionTypeIsolation::Kind::NonIsolated:
+    break;
+
+  case FunctionTypeIsolation::Kind::GlobalActor:
+    diagnoseInvalid(
+        repr, repr->getStartLoc(),
+        diag::nonisolated_nonsending_incompatible_with_global_isolation, repr,
+        fnType->getIsolation().getGlobalActorType());
+    break;
+
+  case FunctionTypeIsolation::Kind::Parameter:
+    diagnoseInvalid(
+        repr, repr->getStartLoc(),
+        diag::nonisolated_nonsending_incompatible_with_isolated_param, repr);
+    break;
+
+  case FunctionTypeIsolation::Kind::Erased:
+    diagnoseInvalid(repr, repr->getStartLoc(),
+                    diag::nonisolated_nonsending_incompatible_with_isolated_any,
+                    repr);
+    break;
+
+  case FunctionTypeIsolation::Kind::NonIsolatedNonsending:
+    llvm_unreachable(
+        "cannot happen because multiple nonisolated(nonsending) attributes "
+        "aren't allowed.");
+  }
+
+  if (repr->isInvalid())
+    return ErrorType::get(getASTContext());
+
+  return fnType->withIsolation(FunctionTypeIsolation::forNonIsolatedCaller());
+}
+
 NeverNullType
 TypeResolver::resolveCompileTimeLiteralTypeRepr(CompileTimeLiteralTypeRepr *repr,
                                                 TypeResolutionOptions options) {
@@ -5293,7 +5496,7 @@ TypeResolver::resolveInlineArrayType(InlineArrayTypeRepr *repr,
   auto argOptions = options.withoutContext().withContext(
       TypeResolverContext::ValueGenericArgument);
 
-  // It's possible the user accidentally wrote '[Int x 4]', correct that here.
+  // It's possible the user accidentally wrote '[Int of 4]', correct that here.
   auto *countRepr = repr->getCount();
   auto *eltRepr = repr->getElement();
   if (!isa<IntegerTypeRepr>(countRepr) && isa<IntegerTypeRepr>(eltRepr)) {
@@ -5796,7 +5999,7 @@ NeverNullType TypeResolver::resolveTupleType(TupleTypeRepr *repr,
         !isa<TupleTypeRepr>(tyR)) {
       auto contextTy = GenericEnvironment::mapTypeIntoContext(
           resolution.getGenericSignature().getGenericEnvironment(), ty);
-      if (contextTy->isNoncopyable())
+      if (!contextTy->hasError() && contextTy->isNoncopyable())
         moveOnlyElementIndex = i;
     }
 
@@ -5916,11 +6119,7 @@ TypeResolver::resolveCompositionType(CompositionTypeRepr *repr,
       continue;
     }
 
-    // FIXME: Support compositions involving parameterized protocol types,
-    // like 'any Collection<String> & Sendable', etc.
-    if (ty->is<ParameterizedProtocolType>() &&
-        !options.isConstraintImplicitExistential() &&
-        options.getContext() != TypeResolverContext::ExistentialConstraint) {
+    if (ty->is<ParameterizedProtocolType>()) {
       checkMember(tyR->getStartLoc(), ty);
       Members.push_back(ty);
       continue;
@@ -6247,14 +6446,23 @@ Type TypeChecker::substMemberTypeWithBase(TypeDecl *member,
                               : member->getDeclaredInterfaceType();
   SubstitutionMap subs;
   if (baseTy) {
-    // Cope with the presence of unbound generic types, which are ill-formed
-    // at this point but break the invariants of getContextSubstitutionMap().
+    // If the base type contains an unbound generic type, we cannot
+    // proceed to the getContextSubstitutionMap() call below.
+    //
+    // In general, this means the user program is ill-formed, but we
+    // do allow type aliases to be referenced with an unbound generic
+    // type as the base, if the underlying type of the type alias
+    // does not contain type parameters.
     if (baseTy->hasUnboundGenericType()) {
       memberType = memberType->getReducedType(aliasDecl->getGenericSignature());
 
+      // This is the error case. The diagnostic is emitted elsewhere,
+      // in TypeChecker::isUnsupportedMemberTypeAccess().
       if (memberType->hasTypeParameter())
         return ErrorType::get(memberType);
 
+      // Otherwise, there's no substitution to be performed, so we
+      // just drop the base type.
       return memberType;
     }
 
@@ -6273,6 +6481,18 @@ Type TypeChecker::substMemberTypeWithBase(TypeDecl *member,
     resultType = TypeAliasType::get(aliasDecl, sugaredBaseTy, {}, resultType);
   }
 
+  // However, if overload resolution finds a value generic decl from name
+  // lookup, replace the returned member type to be the underlying value type
+  // of the generic.
+  //
+  // This can occur in code that does something like: 'type(of: x).a' where
+  // 'a' is the static value generic member.
+  if (auto gp = dyn_cast<GenericTypeParamDecl>(member)) {
+    if (gp->isValue()) {
+      resultType = gp->getValueType();
+    }
+  }
+
   return resultType;
 }
 
@@ -6393,6 +6613,7 @@ class ExistentialTypeSyntaxChecker : public ASTWalker {
     case TypeReprKind::PackElement:
     case TypeReprKind::LifetimeDependent:
     case TypeReprKind::Integer:
+    case TypeReprKind::CallerIsolated:
       return false;
     }
   }
@@ -6497,7 +6718,7 @@ class ExistentialTypeSyntaxChecker : public ASTWalker {
     // A missing `any` or `some` is always diagnosed if this feature not
     // disabled.
     auto featureState = ctx.LangOpts.getFeatureState(Feature::ExistentialAny);
-    if (featureState.isEnabled() || featureState.isEnabledForAdoption()) {
+    if (featureState.isEnabled() || featureState.isEnabledForMigration()) {
       return true;
     }
 
@@ -6590,13 +6811,13 @@ class ExistentialTypeSyntaxChecker : public ASTWalker {
                                       /*isAlias=*/isa<TypeAliasDecl>(decl)));
     }
 
-    // If `ExistentialAny` is enabled in adoption mode, warn unconditionally.
+    // If `ExistentialAny` is enabled in migration mode, warn unconditionally.
     // Otherwise, warn until the feature's coming-of-age language mode.
     const auto feature = Feature::ExistentialAny;
-    if (Ctx.LangOpts.getFeatureState(feature).isEnabledForAdoption()) {
+    if (Ctx.LangOpts.getFeatureState(feature).isEnabledForMigration()) {
       diag->limitBehavior(DiagnosticBehavior::Warning);
     } else {
-      diag->warnUntilSwiftVersion(getFeatureLanguageVersion(feature).value());
+      diag->warnUntilSwiftVersion(feature.getLanguageVersion().value());
     }
 
     emitInsertAnyFixit(*diag, T);
@@ -6759,7 +6980,7 @@ Type ExplicitCaughtTypeRequest::evaluate(
   ASTContext &ctx = *ctxPtr;
 
   // try!/try? always catch 'any Error'.
-  if (catchNode.is<AnyTryExpr *>()) {
+  if (isa<AnyTryExpr *>(catchNode)) {
     return ctx.getErrorExistentialType();
   }
 
@@ -6784,7 +7005,7 @@ Type ExplicitCaughtTypeRequest::evaluate(
 
     return TypeResolution::forInterface(func, options,
                                         /*unboundTyOpener*/ nullptr,
-                                        PlaceholderType::get,
+                                        /*placeholderOpener*/ nullptr,
                                         /*packElementOpener*/ nullptr)
         .resolveType(thrownTypeRepr);
   }
@@ -6796,12 +7017,13 @@ Type ExplicitCaughtTypeRequest::evaluate(
       return TypeResolution::resolveContextualType(
                thrownTypeRepr, closure,
                TypeResolutionOptions(TypeResolverContext::None),
-               /*unboundTyOpener*/ nullptr, PlaceholderType::get,
+               /*unboundTyOpener*/ nullptr, /*placeholderOpener*/ nullptr,
                /*packElementOpener*/ nullptr);
     }
 
     // Explicit 'throws' implies that this throws 'any Error'.
     if (closure->getThrowsLoc().isValid()) {
+      diagnoseUntypedThrowsInEmbedded(closure, closure->getThrowsLoc());
       return ctx.getErrorExistentialType();
     }
 
@@ -6821,13 +7043,15 @@ Type ExplicitCaughtTypeRequest::evaluate(
 
     // If there is no explicitly-specified thrown error type, it's 'any Error'.
     if (!typeRepr) {
+      diagnoseUntypedThrowsInEmbedded(doCatch->getDeclContext(),
+                                      doCatch->getThrowsLoc());
       return ctx.getErrorExistentialType();
     }
 
     return TypeResolution::resolveContextualType(
         typeRepr, doCatch->getDeclContext(),
         TypeResolutionOptions(TypeResolverContext::None),
-        /*unboundTyOpener*/ nullptr, PlaceholderType::get,
+        /*unboundTyOpener*/ nullptr, /*placeholderOpener*/ nullptr,
         /*packElementOpener*/ nullptr);
   }
 
diff --git a/lib/Sema/TypeCheckType.h b/lib/Sema/TypeCheckType.h
index ecf18d2f05e00..dfc7ecec1426d 100644
--- a/lib/Sema/TypeCheckType.h
+++ b/lib/Sema/TypeCheckType.h
@@ -574,6 +574,9 @@ using HandlePlaceholderTypeReprFn =
 using OpenPackElementFn =
     llvm::function_ref<Type(Type, PackElementTypeRepr *)>;
 
+using OpenRequirementFn =
+    llvm::function_ref<void(GenericTypeDecl *, TypeSubstitutionFn)>;
+
 /// Handles the resolution of types within a given declaration context,
 /// which might involve resolving generic parameters to a particular
 /// stage.
@@ -584,6 +587,7 @@ class TypeResolution {
   OpenUnboundGenericTypeFn unboundTyOpener;
   HandlePlaceholderTypeReprFn placeholderHandler;
   OpenPackElementFn packElementOpener;
+  OpenRequirementFn requirementOpener;
   GenericSignature genericSig;
 
 private:
@@ -591,11 +595,13 @@ class TypeResolution {
                  TypeResolutionStage stage, TypeResolutionOptions options,
                  OpenUnboundGenericTypeFn unboundTyOpener,
                  HandlePlaceholderTypeReprFn placeholderHandler,
-                 OpenPackElementFn packElementOpener)
+                 OpenPackElementFn packElementOpener,
+                 OpenRequirementFn requirementOpener)
       : dc(dc), stage(stage), options(options),
         unboundTyOpener(unboundTyOpener),
         placeholderHandler(placeholderHandler),
-        packElementOpener(packElementOpener), genericSig(genericSig) {}
+        packElementOpener(packElementOpener),
+        requirementOpener(requirementOpener), genericSig(genericSig) {}
 
 public:
   /// Form a type resolution for the structure of a type, which does not
@@ -613,7 +619,8 @@ class TypeResolution {
   forInterface(DeclContext *dc, TypeResolutionOptions opts,
                OpenUnboundGenericTypeFn unboundTyOpener,
                HandlePlaceholderTypeReprFn placeholderHandler,
-               OpenPackElementFn packElementOpener);
+               OpenPackElementFn packElementOpener,
+               OpenRequirementFn requirementOpener = nullptr);
 
   /// Form a type resolution for an interface type, which is a complete
   /// description of the type using generic parameters.
@@ -622,7 +629,8 @@ class TypeResolution {
                TypeResolutionOptions opts,
                OpenUnboundGenericTypeFn unboundTyOpener,
                HandlePlaceholderTypeReprFn placeholderHandler,
-               OpenPackElementFn packElementOpener);
+               OpenPackElementFn packElementOpener,
+               OpenRequirementFn requirementOpener = nullptr);
 
   /// Form a type resolution for a contextual type, which is a complete
   /// description of the type using the archetypes of the given generic
@@ -633,14 +641,17 @@ class TypeResolution {
                         OpenUnboundGenericTypeFn unboundTyOpener,
                         HandlePlaceholderTypeReprFn placeholderHandler,
                         OpenPackElementFn packElementOpener,
+                        OpenRequirementFn requirementOpener = nullptr,
                         SILTypeResolutionContext *silContext = nullptr);
 
-  static Type resolveContextualType(
-      TypeRepr *TyR, DeclContext *dc, GenericSignature genericSig,
-      TypeResolutionOptions opts, OpenUnboundGenericTypeFn unboundTyOpener,
-      HandlePlaceholderTypeReprFn placeholderHandler,
-      OpenPackElementFn packElementOpener,
-      SILTypeResolutionContext *silContext = nullptr);
+  static Type
+  resolveContextualType(TypeRepr *TyR, DeclContext *dc,
+                        GenericSignature genericSig, TypeResolutionOptions opts,
+                        OpenUnboundGenericTypeFn unboundTyOpener,
+                        HandlePlaceholderTypeReprFn placeholderHandler,
+                        OpenPackElementFn packElementOpener,
+                        OpenRequirementFn requirementOpener = nullptr,
+                        SILTypeResolutionContext *silContext = nullptr);
 
 public:
   TypeResolution withOptions(TypeResolutionOptions opts) const;
@@ -672,6 +683,10 @@ class TypeResolution {
     return packElementOpener;
   }
 
+  OpenRequirementFn getRequirementOpener() const {
+    return requirementOpener;
+  }
+
   /// Retrieves the generic signature for the context, or NULL if there is
   /// no generic signature to resolve types.
   GenericSignature getGenericSignature() const;
diff --git a/lib/Sema/TypeCheckUnsafe.cpp b/lib/Sema/TypeCheckUnsafe.cpp
index c9ef7d913f175..774df349cf3ec 100644
--- a/lib/Sema/TypeCheckUnsafe.cpp
+++ b/lib/Sema/TypeCheckUnsafe.cpp
@@ -21,11 +21,12 @@
 #include "TypeCheckUnsafe.h"
 
 #include "swift/AST/ASTContext.h"
-#include "swift/AST/Effects.h"
-#include "swift/AST/UnsafeUse.h"
 #include "swift/AST/DiagnosticsSema.h"
+#include "swift/AST/Effects.h"
 #include "swift/AST/PackConformance.h"
 #include "swift/AST/SourceFile.h"
+#include "swift/AST/Types.h"
+#include "swift/AST/UnsafeUse.h"
 
 using namespace swift;
 
@@ -33,8 +34,7 @@ void swift::diagnoseUnsafeUse(const UnsafeUse &use) {
   switch (use.getKind()) {
   case UnsafeUse::Override: {
     auto override = use.getDecl();
-    override->diagnose(
-        diag::override_safe_with_unsafe, override->getDescriptiveKind());
+    override->diagnose(diag::override_safe_with_unsafe, override);
     if (auto overridingClass = override->getDeclContext()->getSelfClassDecl()) {
       overridingClass->diagnose(
           diag::make_subclass_unsafe, overridingClass->getName()
@@ -47,9 +47,7 @@ void swift::diagnoseUnsafeUse(const UnsafeUse &use) {
 
   case UnsafeUse::Witness: {
     auto witness = cast<ValueDecl>(use.getDecl());
-    witness->diagnose(diag::note_witness_unsafe,
-                      witness->getDescriptiveKind(),
-                      witness->getName());
+    witness->diagnose(diag::note_witness_unsafe, witness);
     return;
   }
 
@@ -154,6 +152,40 @@ void swift::diagnoseUnsafeUse(const UnsafeUse &use) {
     return;
   }
 
+  case UnsafeUse::CallArgument: {
+    auto [argumentName, argumentIndex, argument] = use.getCallArgument();
+    Type paramType = use.getType();
+    ASTContext &ctx = paramType->getASTContext();
+
+    SourceLoc loc = argument->getLoc();
+    if (loc.isInvalid())
+      loc = use.getLocation();
+
+    if (auto calleeDecl = dyn_cast_or_null<ValueDecl>(use.getDecl())) {
+      if (argumentName.empty()) {
+        ctx.Diags.diagnose(
+            loc,
+            diag::note_unsafe_call_decl_argument_indexed,
+            calleeDecl, argumentIndex, argument->getType())
+          .highlight(argument->getSourceRange());
+      } else {
+        ctx.Diags.diagnose(
+            loc,
+            diag::note_unsafe_call_decl_argument_named,
+            calleeDecl, argumentName, argument->getType())
+          .highlight(argument->getSourceRange());
+      }
+    } else {
+      ctx.Diags.diagnose(
+          loc,
+          diag::note_unsafe_call_argument_indexed,
+          argumentIndex, argument->getType())
+        .highlight(argument->getSourceRange());
+    }
+
+    return;
+  }
+
   case UnsafeUse::TemporarilyEscaping: {
     Type type = use.getType();
     ASTContext &ctx = type->getASTContext();
@@ -164,7 +196,9 @@ void swift::diagnoseUnsafeUse(const UnsafeUse &use) {
 
   case UnsafeUse::PreconcurrencyImport: {
     auto importDecl = cast<ImportDecl>(use.getDecl());
-    importDecl->diagnose(diag::preconcurrency_import_unsafe);
+    importDecl->diagnose(diag::preconcurrency_import_unsafe)
+      .fixItInsert(importDecl->getAttributeInsertionLoc(false), "@unsafe ");
+
     return;
   }
   }
@@ -180,6 +214,7 @@ static bool isReferenceToNonisolatedUnsafe(ValueDecl *decl) {
 bool swift::enumerateUnsafeUses(ConcreteDeclRef declRef,
                                 SourceLoc loc,
                                 bool isCall,
+                                bool skipTypeCheck,
                                 llvm::function_ref<bool(UnsafeUse)> fn) {
   // If the declaration is explicitly unsafe, note that.
   auto decl = declRef.getDecl();
@@ -206,19 +241,29 @@ bool swift::enumerateUnsafeUses(ConcreteDeclRef declRef,
   // If the type of this declaration involves unsafe types, diagnose that.
   ASTContext &ctx = decl->getASTContext();
   auto subs = declRef.getSubstitutions();
-  {
-    auto type = decl->getInterfaceType();
-    if (subs) {
-      if (auto *genericFnType = type->getAs<GenericFunctionType>())
-        type = genericFnType->substGenericArgs(subs);
-      else
-        type = type.subst(subs);
-    }
+  auto type = decl->getInterfaceType();
+  if (subs) {
+    if (auto *genericFnType = type->getAs<GenericFunctionType>())
+      type = genericFnType->substGenericArgs(subs);
+    else
+      type = type.subst(subs);
+  }
 
+  if (skipTypeCheck) {
+    // We check the arguements instead of the funcion type for function calls.
+    // On the other hand, we still need to check the return type as we might not
+    // have a declRef with the type of the return type. E.g. in
+    // `return funcionCall()`.
+    if (auto *fnTy = type->getAs<AnyFunctionType>())
+      type = fnTy->getResult();
+    else
+      type = Type();
+  }
+  if (type) {
     bool shouldReturnTrue = false;
     diagnoseUnsafeType(ctx, loc, type, [&](Type unsafeType) {
       if (fn(UnsafeUse::forReferenceToUnsafe(
-               decl, isCall && !isa<ParamDecl>(decl), unsafeType, loc)))
+              decl, isCall && !isa<ParamDecl>(decl), unsafeType, loc)))
         shouldReturnTrue = true;
     });
 
@@ -306,10 +351,6 @@ bool swift::enumerateUnsafeUses(ArrayRef<ProtocolConformanceRef> conformances,
     if (conformance.isInvalid())
       continue;
 
-    ASTContext &ctx = conformance.getProtocol()->getASTContext();
-    if (!ctx.LangOpts.hasFeature(Feature::StrictMemorySafety))
-      return false;
-
     if (!conformance.hasEffect(EffectKind::Unsafe))
       continue;
 
@@ -330,7 +371,12 @@ bool swift::enumerateUnsafeUses(ArrayRef<ProtocolConformanceRef> conformances,
 bool swift::enumerateUnsafeUses(SubstitutionMap subs,
                                 SourceLoc loc,
                                 llvm::function_ref<bool(UnsafeUse)> fn) {
-  // FIXME: Check replacement types?
+  // Replacement types.
+  for (auto replacementType : subs.getReplacementTypes()) {
+    if (replacementType->isUnsafe() &&
+        fn(UnsafeUse::forReferenceToUnsafe(nullptr, false, replacementType, loc)))
+      return true;
+  }
 
   // Check conformances.
   if (enumerateUnsafeUses(subs.getConformances(), loc, fn))
@@ -341,7 +387,8 @@ bool swift::enumerateUnsafeUses(SubstitutionMap subs,
 
 bool swift::isUnsafe(ConcreteDeclRef declRef) {
   return enumerateUnsafeUses(
-      declRef, SourceLoc(), /*isCall=*/false, [&](UnsafeUse) {
+      declRef, SourceLoc(), /*isCall=*/false, /*skipTypeCheck=*/false,
+      [&](UnsafeUse) {
     return true;
   });
 }
@@ -372,24 +419,73 @@ bool swift::isUnsafeInConformance(const ValueDecl *requirement,
 
 void swift::diagnoseUnsafeType(ASTContext &ctx, SourceLoc loc, Type type,
                                llvm::function_ref<void(Type)> diagnose) {
-  if (!ctx.LangOpts.hasFeature(Feature::StrictMemorySafety))
+  if (!type->isUnsafe())
     return;
 
-  if (!type->isUnsafe() && !type->getCanonicalType()->isUnsafe())
-    return;
+  // Look for a specific @unsafe nominal type along the way.
+  class Walker : public TypeWalker {
+  public:
+    Type specificType;
+
+    Action walkToTypePre(Type type) override {
+      if (specificType)
+        return Action::Stop;
+
+      // If this refers to a nominal type that is @unsafe, store that.
+      if (auto typeDecl = type->getAnyNominal()) {
+        if (typeDecl->getExplicitSafety() == ExplicitSafety::Unsafe) {
+          specificType = type;
+          return Action::Stop;
+        }
+      }
+
+      // Do not recurse into nominal types, because we do not want to visit
+      // their "parent" types.
+      if (isa<NominalOrBoundGenericNominalType>(type.getPointer()) ||
+          isa<UnboundGenericType>(type.getPointer())) {
+        // Recurse into the generic arguments. This operation is recursive,
+        // because we also need to see the generic arguments of parent types.
+        walkGenericArguments(type);
+
+        return Action::SkipNode;
+      }
+
+      return Action::Continue;
+    }
+
+  private:
+    /// Recursively walk the generic arguments of this type and its parent
+    /// types.
+    void walkGenericArguments(Type type) {
+      if (!type)
+        return;
 
-  // Look for a specific @unsafe nominal type.
-  Type specificType;
-  type.findIf([&specificType](Type type) {
-    if (auto typeDecl = type->getAnyNominal()) {
-      if (typeDecl->getExplicitSafety() == ExplicitSafety::Unsafe) {
-        specificType = type;
-        return false;
+      // Walk the generic arguments.
+      if (auto boundGeneric = type->getAs<BoundGenericType>()) {
+        for (auto genericArg : boundGeneric->getGenericArgs())
+          genericArg.walk(*this);
       }
+
+      if (auto nominalOrBound = type->getAs<NominalOrBoundGenericNominalType>())
+        return walkGenericArguments(nominalOrBound->getParent());
+
+      if (auto unbound = type->getAs<UnboundGenericType>())
+        return walkGenericArguments(unbound->getParent());
     }
+  };
 
-    return false;
-  });
+  // Look for a canonical unsafe type.
+  Walker walker;
+  type->getCanonicalType().walk(walker);
+  Type specificType = walker.specificType;
+
+  // Look for an unsafe type in the non-canonical type, which is a better answer
+  // if we can find it.
+  walker.specificType = Type();
+  type.walk(walker);
+  if (specificType && walker.specificType &&
+      specificType->isEqual(walker.specificType))
+    specificType = walker.specificType;
 
   diagnose(specificType ? specificType : type);
 }
diff --git a/lib/Sema/TypeCheckUnsafe.h b/lib/Sema/TypeCheckUnsafe.h
index 0122e3c86eeff..ebcdef239f791 100644
--- a/lib/Sema/TypeCheckUnsafe.h
+++ b/lib/Sema/TypeCheckUnsafe.h
@@ -34,6 +34,7 @@ void diagnoseUnsafeUse(const UnsafeUse &use);
 bool enumerateUnsafeUses(ConcreteDeclRef declRef,
                          SourceLoc loc,
                          bool isCall,
+                         bool skipTypeCheck,
                          llvm::function_ref<bool(UnsafeUse)> fn);
 
 /// Enumerate all of the unsafe uses that occur within this array of protocol
diff --git a/lib/Sema/TypeChecker.cpp b/lib/Sema/TypeChecker.cpp
index d7e5a290a1398..bb49ccc5d914d 100644
--- a/lib/Sema/TypeChecker.cpp
+++ b/lib/Sema/TypeChecker.cpp
@@ -190,13 +190,17 @@ ModuleDecl *TypeChecker::getStdlibModule(const DeclContext *dc) {
   return dc->getParentModule();
 }
 
-void swift::bindExtensions(ModuleDecl &mod) {
+evaluator::SideEffect
+BindExtensionsRequest::evaluate(Evaluator &evaluator, ModuleDecl *M) const {
+  bool excludeMacroExpansions = true;
+
   // Utility function to try and resolve the extended type without diagnosing.
   // If we succeed, we go ahead and bind the extension. Otherwise, return false.
   auto tryBindExtension = [&](ExtensionDecl *ext) -> bool {
     assert(!ext->canNeverBeBound() &&
            "Only extensions that can ever be bound get here.");
-    if (auto nominal = ext->computeExtendedNominal()) {
+    if (auto nominal = ext->computeExtendedNominal(excludeMacroExpansions)) {
+      ext->setExtendedNominal(nominal);
       nominal->addExtension(ext);
       return true;
     }
@@ -208,7 +212,7 @@ void swift::bindExtensions(ModuleDecl &mod) {
   // resolved to a worklist.
   SmallVector<ExtensionDecl *, 8> worklist;
 
-  for (auto file : mod.getFiles()) {
+  for (auto file : M->getFiles()) {
     auto *SF = dyn_cast<SourceFile>(file);
     if (!SF)
       continue;
@@ -228,22 +232,39 @@ void swift::bindExtensions(ModuleDecl &mod) {
       visitTopLevelDecl(D);
   }
 
-  // Phase 2 - repeatedly go through the worklist and attempt to bind each
-  // extension there, removing it from the worklist if we succeed.
-  bool changed;
-  do {
-    changed = false;
-
-    auto last = std::remove_if(worklist.begin(), worklist.end(),
-                               tryBindExtension);
-    if (last != worklist.end()) {
-      worklist.erase(last, worklist.end());
-      changed = true;
-    }
-  } while(changed);
+  auto tryBindExtensions = [&]() {
+    // Phase 2 - repeatedly go through the worklist and attempt to bind each
+    // extension there, removing it from the worklist if we succeed.
+    bool changed;
+    do {
+      changed = false;
+
+      auto last = std::remove_if(worklist.begin(), worklist.end(),
+                                 tryBindExtension);
+      if (last != worklist.end()) {
+        worklist.erase(last, worklist.end());
+        changed = true;
+      }
+    } while(changed);
+  };
+
+  tryBindExtensions();
 
+  // If that fails, try again, but this time expand macros.
+  excludeMacroExpansions = false;
+  tryBindExtensions();
+  
   // Any remaining extensions are invalid. They will be diagnosed later by
   // typeCheckDecl().
+  for (auto *ext : worklist)
+    ext->setExtendedNominal(nullptr);
+
+  return {};
+}
+
+void swift::bindExtensions(ModuleDecl &mod) {
+  auto &eval = mod.getASTContext().evaluator;
+  (void)evaluateOrDefault(eval, BindExtensionsRequest{&mod}, {});
 }
 
 void swift::performTypeChecking(SourceFile &SF) {
@@ -283,10 +304,6 @@ TypeCheckPrimaryFileRequest::evaluate(Evaluator &eval, SourceFile *SF) const {
     // checking.
     (void)AvailabilityScope::getOrBuildForSourceFile(*SF);
 
-    // Before we type check any of the top level code decls, generate the per
-    // file language options.
-    (void)SF->getLanguageOptions();
-
     // Type check the top-level elements of the source file.
     for (auto D : SF->getTopLevelDecls()) {
       if (auto *TLCD = dyn_cast<TopLevelCodeDecl>(D)) {
@@ -320,9 +337,13 @@ TypeCheckPrimaryFileRequest::evaluate(Evaluator &eval, SourceFile *SF) const {
       }
     }
     SF->typeCheckDelayedFunctions();
+
+    for (auto *opaqueDecl : SF->getOpaqueReturnTypeDecls()) {
+      TypeChecker::checkCircularOpaqueReturnTypeDecl(opaqueDecl);
+    }
   }
 
-  // If region based isolation is enabled, we diagnose unnecessary
+  // If region-based isolation is enabled, we diagnose unnecessary
   // preconcurrency imports in the SIL pipeline in the
   // DiagnoseUnnecessaryPreconcurrencyImports pass.
   if (!Ctx.LangOpts.hasFeature(Feature::RegionBasedIsolation))
@@ -363,6 +384,10 @@ TypeCheckPrimaryFileRequest::evaluate(Evaluator &eval, SourceFile *SF) const {
       Ctx.evaluator,
       CheckInconsistentWeakLinkedImportsRequest{SF->getParentModule()}, {});
 
+  // Opt-in performance hint diagnostics for performance-critical code.
+  if (performanceHintDiagnosticsEnabled(Ctx))
+    evaluateOrDefault(Ctx.evaluator, EmitPerformanceHints{SF}, {});
+
   // Perform various AST transforms we've been asked to perform.
   if (!Ctx.hadError() && Ctx.LangOpts.DebuggerTestingTransform)
     performDebuggerTestingTransform(*SF);
@@ -550,13 +575,6 @@ bool swift::typeCheckASTNodeAtLoc(TypeCheckASTNodeAtLocContext TypeCheckCtx,
       true);
 }
 
-bool swift::typeCheckForCodeCompletion(
-    constraints::SyntacticElementTarget &target, bool needsPrecheck,
-    llvm::function_ref<void(const constraints::Solution &)> callback) {
-  return TypeChecker::typeCheckForCodeCompletion(target, needsPrecheck,
-                                                 callback);
-}
-
 Expr *swift::resolveDeclRefExpr(UnresolvedDeclRefExpr *UDRE,
                                 DeclContext *Context) {
   return TypeChecker::resolveDeclRefExpr(UDRE, Context);
diff --git a/lib/Sema/TypeChecker.h b/lib/Sema/TypeChecker.h
index d760a88998610..f0ab3ea2ecf75 100644
--- a/lib/Sema/TypeChecker.h
+++ b/lib/Sema/TypeChecker.h
@@ -496,6 +496,8 @@ std::optional<BraceStmt *> applyResultBuilderBodyTransform(FuncDecl *func,
 
 bool typeCheckTapBody(TapExpr *expr, DeclContext *DC);
 
+void collectReferencedGenericParams(Type ty, SmallPtrSet<CanType, 4> &referenced);
+
 Type typeCheckParameterDefault(Expr *&defaultValue, DeclContext *DC,
                                Type paramType, bool isAutoClosure,
                                bool atCallerSide);
@@ -504,6 +506,8 @@ void typeCheckTopLevelCodeDecl(TopLevelCodeDecl *TLCD);
 
 void typeCheckDecl(Decl *D);
 
+void checkCircularOpaqueReturnTypeDecl(OpaqueTypeDecl *opaqueDecl);
+
 void addImplicitDynamicAttribute(Decl *D);
 void checkDeclAttributes(Decl *D);
 void checkDeclABIAttribute(Decl *apiDecl, ABIAttr *abiAttr);
@@ -666,7 +670,7 @@ void filterSolutionsForCodeCompletion(
 /// \returns `true` if target was applicable and it was possible to infer
 /// types for code completion, `false` otherwise.
 bool typeCheckForCodeCompletion(
-    constraints::SyntacticElementTarget &target, bool needsPrecheck,
+    constraints::SyntacticElementTarget &target,
     llvm::function_ref<void(const constraints::Solution &)> callback);
 
 /// Check the key-path expression.
@@ -749,8 +753,10 @@ Pattern *resolvePattern(Pattern *P, DeclContext *dc, bool isStmtCondition);
 ///
 /// \returns the type of the pattern, which may be an error type if an
 /// unrecoverable error occurred. If the options permit it, the type may
-/// involve \c UnresolvedType (for patterns with no type information) and
+/// involve \c PlaceholderType (for patterns with no type information) and
 /// unbound generic types.
+/// TODO: We ought to expose hooks that let callers open the
+/// PlaceholderTypes directly, similar to type resolution.
 Type typeCheckPattern(ContextualPattern pattern);
 
 /// Attempt to simplify an ExprPattern into a BoolPattern or
@@ -793,14 +799,12 @@ bool typeCheckPatternBinding(PatternBindingDecl *PBD, unsigned patternNumber,
 /// together.
 ///
 /// \returns true if a failure occurred.
-bool typeCheckForEachPreamble(DeclContext *dc, ForEachStmt *stmt);
+bool typeCheckForEachPreamble(DeclContext *dc, ForEachStmt *stmt,
+                              bool skipWhereClause);
 
 /// Compute the set of captures for the given closure.
 void computeCaptures(AbstractClosureExpr *ACE);
 
-/// Check for invalid captures from stored property initializers.
-void checkPatternBindingCaptures(IterableDeclContext *DC);
-
 /// Update the DeclContexts for AST nodes in a given DeclContext. This is
 /// necessary after type-checking since autoclosures may have been introduced.
 void contextualizeExpr(Expr *E, DeclContext *DC);
@@ -1026,15 +1030,6 @@ bool diagnoseConformanceExportability(SourceLoc loc,
 /// potentially unavailable API elements
 /// @{
 
-/// Returns true if the availability of the witness
-/// is sufficient to safely conform to the requirement in the context
-/// the provided conformance. On return, requiredAvailability holds th
-/// availability levels required for conformance.
-bool isAvailabilitySafeForConformance(
-    const ProtocolDecl *proto, const ValueDecl *requirement,
-    const ValueDecl *witness, const DeclContext *dc,
-    AvailabilityRange &requiredAvailability);
-
 /// Returns a diagnostic indicating why the declaration cannot be annotated
 /// with an @available() attribute indicating it is potentially unavailable
 /// or None if this is allowed.
@@ -1246,24 +1241,6 @@ bool diagnoseInvalidFunctionType(FunctionType *fnTy, SourceLoc loc,
                                  std::optional<FunctionTypeRepr *> repr,
                                  DeclContext *dc,
                                  std::optional<TypeResolutionStage> stage);
-
-/// Walk the parallel structure of a type with user-provided placeholders and
-/// an inferred type produced by the type checker. Where placeholders can be
-/// found, suggest the corresponding inferred type.
-///
-/// For example,
-///
-/// \code
-///  func foo(_ x: [_] = [0])
-/// \endcode
-///
-/// Has a written type of `(ArraySlice (Placeholder))` and an inferred type of
-/// `(ArraySlice Int)`, so we walk to `Placeholder` and `Int` in each type and
-/// suggest replacing `_` with `Int`.
-///
-/// \param writtenType The interface type usually derived from a user-written
-/// type repr. \param inferredType The type inferred by the type checker.
-void notePlaceholderReplacementTypes(Type writtenType, Type inferredType);
 } // namespace TypeChecker
 
 /// Returns the protocol requirement kind of the given declaration.
@@ -1424,26 +1401,9 @@ bool checkFallthroughStmt(FallthroughStmt *stmt);
 void checkUnknownAttrRestrictions(
     ASTContext &ctx, CaseStmt *caseBlock, bool &limitExhaustivityChecks);
 
-/// Bind all of the pattern variables that occur within a case statement and
-/// all of its case items to their "parent" pattern variables, forming chains
-/// of variables with the same name.
-///
-/// Given a case such as:
-/// \code
-/// case .a(let x), .b(let x), .c(let x):
-/// \endcode
-///
-/// Each case item contains a (different) pattern variable named.
-/// "x". This function will set the "parent" variable of the
-/// second and third "x" variables to the "x" variable immediately
-/// to its left. A fourth "x" will be the body case variable,
-/// whose parent will be set to the "x" within the final case
-/// item.
-///
-/// Each of the "x" variables must eventually have the same type, and agree on
-/// let vs. var. This function does not perform any of that validation, leaving
-/// it to later stages.
-void bindSwitchCasePatternVars(DeclContext *dc, CaseStmt *stmt);
+/// Diagnoses any mutability mismatches for any same-named variables bound by
+/// given CaseStmt.
+void diagnoseCaseVarMutabilityMismatch(DeclContext *dc, CaseStmt *stmt);
 
 /// If \p attr was added by an access note, wraps the error in
 /// \c diag::wrap_invalid_attr_added_by_access_note and limits it as an access
@@ -1517,12 +1477,20 @@ using RequiredImportAccessLevelCallback =
     std::function<void(AttributedImport<ImportedModule>)>;
 
 /// Make a note that uses of \p decl in \p dc require that the decl's defining
-/// module be imported with an access level that is at least as permissive as \p
-/// accessLevel.
+/// module be imported with an access level that is at least as permissive as
+/// \p accessLevel.
 void recordRequiredImportAccessLevelForDecl(
     const Decl *decl, const DeclContext *dc, AccessLevel accessLevel,
     RequiredImportAccessLevelCallback remark);
 
+/// Make a note that uses of \p decl in \p dc require that the decl's defining
+/// module be imported with an access level that is at least as permissive as
+/// \p accessLevel. If `-Rmodule-api-import` is specified, a remark is emitted.
+void recordRequiredImportAccessLevelForDecl(const ValueDecl *decl,
+                                            const DeclContext *dc,
+                                            AccessLevel accessLevel,
+                                            SourceLoc loc);
+
 /// Report imports that are marked public but are not used in API.
 void diagnoseUnnecessaryPublicImports(SourceFile &SF);
 
@@ -1531,21 +1499,14 @@ void diagnoseUnnecessaryPublicImports(SourceFile &SF);
 /// delayed, the diagnostic will instead be emitted after type checking the
 /// entire file and will include an appropriate fix-it. Returns true if a
 /// diagnostic was emitted (and not delayed).
-bool maybeDiagnoseMissingImportForMember(const ValueDecl *decl,
-                                         const DeclContext *dc, SourceLoc loc);
+bool maybeDiagnoseMissingImportForMember(
+    const ValueDecl *decl, const DeclContext *dc, SourceLoc loc,
+    DiagnosticBehavior limit = DiagnosticBehavior::Unspecified);
 
 /// Emit delayed diagnostics regarding imports that should be added to the
 /// source file.
 void diagnoseMissingImports(SourceFile &sf);
 
-/// Determine whether the type parameter has requirements that would prohibit
-/// it from using any isolated conformances.
-///
-/// Returns the protocol to which the type conforms that causes the conflict,
-/// which can be either Sendable or SendableMetatype.
-std::optional<ProtocolDecl *> typeParameterProhibitsIsolatedConformance(
-    Type type, GenericSignature signature);
-
 } // end namespace swift
 
 #endif
diff --git a/lib/Sema/TypeOfReference.cpp b/lib/Sema/TypeOfReference.cpp
index 791f493a0841c..bec20874a37fa 100644
--- a/lib/Sema/TypeOfReference.cpp
+++ b/lib/Sema/TypeOfReference.cpp
@@ -22,15 +22,20 @@
 #include "TypeCheckType.h"
 #include "TypeChecker.h"
 #include "swift/AST/ConformanceLookup.h"
-#include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/Effects.h"
+#include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/MacroDefinition.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/ProtocolConformance.h"
+#include "swift/AST/Type.h"
 #include "swift/AST/TypeTransform.h"
-#include "swift/Sema/ConstraintSystem.h"
+#include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/Basic/Defer.h"
 #include "swift/Basic/Statistic.h"
+#include "swift/ClangImporter/ClangModule.h"
+#include "swift/Sema/ConstraintSystem.h"
+#include "swift/Sema/PreparedOverload.h"
 
 using namespace swift;
 using namespace constraints;
@@ -43,18 +48,21 @@ using namespace inference;
 Type ConstraintSystem::openUnboundGenericType(GenericTypeDecl *decl,
                                               Type parentTy,
                                               ConstraintLocatorBuilder locator,
-                                              bool isTypeResolution) {
+                                              bool isTypeResolution,
+                                              PreparedOverloadBuilder *preparedOverload) {
   if (parentTy) {
-    parentTy = replaceInferableTypesWithTypeVars(parentTy, locator);
+    parentTy = replaceInferableTypesWithTypeVars(
+        parentTy, locator, preparedOverload);
   }
 
   // Open up the generic type.
   SmallVector<OpenedType, 4> replacements;
   openGeneric(decl->getDeclContext(), decl->getGenericSignature(), locator,
-              replacements);
+              replacements, preparedOverload);
 
   // FIXME: Get rid of fixmeAllowDuplicates.
-  recordOpenedTypes(locator, replacements, /*fixmeAllowDuplicates=*/true);
+  recordOpenedTypes(locator, replacements, preparedOverload,
+                    /*fixmeAllowDuplicates=*/true);
 
   if (parentTy) {
     const auto parentTyInContext =
@@ -81,7 +89,7 @@ Type ConstraintSystem::openUnboundGenericType(GenericTypeDecl *decl,
         continue;
 
       addConstraint(ConstraintKind::Bind, pair.second, found->second,
-                    locator);
+                    locator, /*isFavored=*/false, preparedOverload);
     }
   }
 
@@ -105,7 +113,8 @@ Type ConstraintSystem::openUnboundGenericType(GenericTypeDecl *decl,
           DC, std::nullopt,
           [](auto) -> Type { llvm_unreachable("should not be used"); },
           [](auto &, auto) -> Type { llvm_unreachable("should not be used"); },
-          [](auto, auto) -> Type { llvm_unreachable("should not be used"); })
+          [](auto, auto) -> Type { llvm_unreachable("should not be used"); },
+          [](auto, auto) { /*will be called, but we already handled reqs*/ })
           .applyUnboundGenericArguments(decl, parentTy, SourceLoc(), arguments);
   if (!parentTy && !isTypeResolution) {
     result = DC->mapTypeIntoContext(result);
@@ -115,7 +124,8 @@ Type ConstraintSystem::openUnboundGenericType(GenericTypeDecl *decl,
 }
 
 static void checkNestedTypeConstraints(ConstraintSystem &cs, Type type,
-                                       ConstraintLocatorBuilder locator) {
+                                       ConstraintLocatorBuilder locator,
+                                       PreparedOverloadBuilder *preparedOverload) {
   // If this is a type defined inside of constrained extension, let's add all
   // of the generic requirements to the constraint system to make sure that it's
   // something we can use.
@@ -184,54 +194,165 @@ static void checkNestedTypeConstraints(ConstraintSystem &cs, Type type,
             // U is an associated type of protocol P.
             return type.subst(QuerySubstitutionMap{contextSubMap},
                               LookUpConformanceInSubstitutionMap(subMap));
-          });
+          }, preparedOverload);
     }
   }
 
   // And now make sure the parent is okay, for things like X<T>.Y.Z.
-  checkNestedTypeConstraints(cs, parentTy, locator);
+  checkNestedTypeConstraints(cs, parentTy, locator, preparedOverload);
 }
 
-Type ConstraintSystem::replaceInferableTypesWithTypeVars(
-    Type type, ConstraintLocatorBuilder locator) {
-  if (!type->hasUnboundGenericType() && !type->hasPlaceholder())
-    return type;
+namespace {
+class InferableTypeOpener final {
+  ConstraintSystem &cs;
+  ConstraintLocatorBuilder locator;
+  PreparedOverloadBuilder *preparedOverload;
 
-  type = type.transformRec([&](Type type) -> std::optional<Type> {
-      if (auto unbound = type->getAs<UnboundGenericType>()) {
-        return openUnboundGenericType(unbound->getDecl(), unbound->getParent(),
-                                      locator, /*isTypeResolution=*/false);
-      } else if (auto *placeholderTy = type->getAs<PlaceholderType>()) {
-        if (auto *typeRepr =
-                placeholderTy->getOriginator().dyn_cast<TypeRepr *>()) {
-          if (isa<PlaceholderTypeRepr>(typeRepr)) {
-            return Type(createTypeVariable(
-                getConstraintLocator(locator,
-                                     LocatorPathElt::PlaceholderType(typeRepr)),
-                TVO_CanBindToNoEscape | TVO_PrefersSubtypeBinding |
-                    TVO_CanBindToHole));
-          }
-        } else if (auto *var =
-                       placeholderTy->getOriginator().dyn_cast<VarDecl *>()) {
-          if (var->getName().hasDollarPrefix()) {
-            auto *repr =
-                new (type->getASTContext()) PlaceholderTypeRepr(var->getLoc());
-            return Type(createTypeVariable(
-                getConstraintLocator(locator,
-                                     LocatorPathElt::PlaceholderType(repr)),
-                TVO_CanBindToNoEscape | TVO_PrefersSubtypeBinding |
-                    TVO_CanBindToHole));
-          }
-        }
+public:
+  InferableTypeOpener(ConstraintSystem &cs, ConstraintLocatorBuilder locator,
+                      PreparedOverloadBuilder *preparedOverload)
+      : cs(cs), locator(locator), preparedOverload(preparedOverload) {}
+
+  TypeVariableType *createTypeVariable(ConstraintLocator *loc) {
+    auto flags =
+        TVO_CanBindToNoEscape | TVO_PrefersSubtypeBinding | TVO_CanBindToHole;
+    return cs.createTypeVariable(loc, flags, preparedOverload);
+  }
+
+  Type transformUnboundGenericType(UnboundGenericType *unbound) {
+    return cs.openUnboundGenericType(unbound->getDecl(), unbound->getParent(),
+                                     locator, /*isTypeResolution=*/false,
+                                     preparedOverload);
+  }
+
+  Type transformPlaceholderType(PlaceholderType *placeholderTy) {
+    auto originator = placeholderTy->getOriginator();
+    if (auto *typeRepr = originator.dyn_cast<TypeRepr *>()) {
+      if (isa<PlaceholderTypeRepr>(typeRepr)) {
+        auto *loc = cs.getConstraintLocator(
+            locator, LocatorPathElt::PlaceholderType(typeRepr));
+        return createTypeVariable(loc);
+      }
+    } else if (auto *var = originator.dyn_cast<VarDecl *>()) {
+      if (var->getName().hasDollarPrefix()) {
+        auto *repr =
+            new (cs.getASTContext()) PlaceholderTypeRepr(var->getLoc());
+        auto *loc = cs.getConstraintLocator(
+            locator, LocatorPathElt::PlaceholderType(repr));
+        return createTypeVariable(loc);
       }
+    }
+    return placeholderTy;
+  }
+
+  void openGenericTypeRequirements(GenericTypeDecl *D, SubstitutionMap subs) {
+    OpenGenericTypeRequirements openReqs(cs, locator, preparedOverload);
+    openReqs(D, QuerySubstitutionMap{subs});
+  }
+
+  Type transformBoundGenericType(BoundGenericType *genericTy) {
+    SmallVector<Type, 4> genericArgs;
+    for (auto arg : genericTy->getGenericArgs())
+      genericArgs.push_back(transform(arg));
+
+    auto substTy = BoundGenericType::get(
+        genericTy->getDecl(), transform(genericTy->getParent()), genericArgs);
+
+    openGenericTypeRequirements(substTy->getDecl(),
+                                substTy->getContextSubstitutionMap());
+    return substTy;
+  }
+
+  Type transformTypeAliasType(TypeAliasType *aliasTy) {
+    auto *TAD = aliasTy->getDecl();
+
+    // For a non-generic typealias, we can simply recurse into the underlying
+    // type. The constraint system doesn't properly handle opened types in
+    // the underlying type of a typealias (e.g TypeWalker won't visit them),
+    // so we don't preserve the sugar.
+    if (!TAD->getGenericSignature())
+      return transform(aliasTy->getSinglyDesugaredType());
+
+    // Otherwise we have a generic typealias, or typealias in a generic context,
+    // and need to open any requirements introduced. Then we need to
+    // re-substitute any opened types into the underlying type. Like the
+    // non-generic codepath we also don't want to preserve sugar.
+    SmallVector<Type, 4> genericArgs;
+    for (auto arg : aliasTy->getDirectGenericArgs())
+      genericArgs.push_back(transform(arg));
+
+    auto parentTy = transform(aliasTy->getParent());
+    auto subMap = TypeAliasType::get(TAD, parentTy, genericArgs,
+                                     aliasTy->getSinglyDesugaredType())
+                      ->getSubstitutionMap(/*wantContextualType*/ true);
+
+    openGenericTypeRequirements(TAD, subMap);
+    return transform(TAD->getUnderlyingType().subst(subMap));
+  }
+
+  Type transformErrorType(ErrorType *errTy) {
+    // For ErrorTypes we want to eagerly produce a hole since we know this is
+    // where the issue is.
+    return PlaceholderType::get(cs.getASTContext(), errTy);
+  }
+
+  Type transformDependentMemberType(DependentMemberType *DMT) {
+    auto assocTy = DMT->getAssocType();
+    ASSERT(assocTy && "Should not have structural type here");
+
+    // If the new base is a hole, propagate it to cover the entire
+    // DependentMemberType.
+    auto newBase = transform(DMT->getBase());
+    if (newBase->isPlaceholder())
+      return PlaceholderType::get(cs.getASTContext(), DMT);
+
+    return DependentMemberType::get(newBase, assocTy);
+  }
+
+  Type transform(Type type) {
+    if (!type)
+      return type;
+    if (!type->hasUnboundGenericType() && !type->hasPlaceholder() &&
+        !type->hasError()) {
+      return type;
+    }
+    // If the type has an error, we can't apply the solution. Record a fix for
+    // an invalid AST node.
+    if (type->hasError()) {
+      cs.recordFix(
+          IgnoreInvalidASTNode::create(cs, cs.getConstraintLocator(locator)),
+          /*impact=*/1, preparedOverload);
+    }
+    return type.transformRec([&](Type type) -> std::optional<Type> {
+      if (!type->hasUnboundGenericType() && !type->hasPlaceholder() &&
+          !type->hasError()) {
+        return type;
+      }
+      auto *tyPtr = type.getPointer();
+      if (auto unbound = dyn_cast<UnboundGenericType>(tyPtr))
+        return transformUnboundGenericType(unbound);
+      if (auto *placeholderTy = dyn_cast<PlaceholderType>(tyPtr))
+        return transformPlaceholderType(placeholderTy);
+      if (auto *genericTy = dyn_cast<BoundGenericType>(tyPtr))
+        return transformBoundGenericType(genericTy);
+      if (auto *aliasTy = dyn_cast<TypeAliasType>(tyPtr))
+        return transformTypeAliasType(aliasTy);
+      if (auto *errTy = dyn_cast<ErrorType>(tyPtr))
+        return transformErrorType(errTy);
+      if (auto *DMT = dyn_cast<DependentMemberType>(tyPtr))
+        return transformDependentMemberType(DMT);
 
       return std::nullopt;
     });
+  }
+};
+} // end anonymous namespace
 
-  if (!type)
-    return ErrorType::get(getASTContext());
-
-  return type;
+Type ConstraintSystem::replaceInferableTypesWithTypeVars(
+    Type type, ConstraintLocatorBuilder locator,
+    PreparedOverloadBuilder *preparedOverload) {
+  InferableTypeOpener opener(*this, locator, preparedOverload);
+  return opener.transform(type);
 }
 
 namespace {
@@ -239,13 +360,16 @@ namespace {
 struct TypeOpener : public TypeTransform<TypeOpener> {
   ArrayRef<OpenedType> replacements;
   ConstraintLocatorBuilder locator;
+  PreparedOverloadBuilder *preparedOverload;
   ConstraintSystem &cs;
 
   TypeOpener(ArrayRef<OpenedType> replacements,
              ConstraintLocatorBuilder locator,
+             PreparedOverloadBuilder *preparedOverload,
              ConstraintSystem &cs)
       : TypeTransform<TypeOpener>(cs.getASTContext()),
-        replacements(replacements), locator(locator), cs(cs) {}
+        replacements(replacements), locator(locator),
+        preparedOverload(preparedOverload), cs(cs) {}
 
   std::optional<Type> transform(TypeBase *type, TypePosition pos) {
     if (!type->hasTypeParameter())
@@ -268,7 +392,8 @@ struct TypeOpener : public TypeTransform<TypeOpener> {
 
   Type transformPackExpansionType(PackExpansionType *expansion,
                                   TypePosition pos) {
-    return cs.openPackExpansionType(expansion, replacements, locator);
+    return cs.openPackExpansionType(expansion, replacements, locator,
+                                    preparedOverload);
   }
 
   bool shouldUnwrapVanishingTuples() const {
@@ -283,47 +408,78 @@ struct TypeOpener : public TypeTransform<TypeOpener> {
 }
 
 Type ConstraintSystem::openType(Type type, ArrayRef<OpenedType> replacements,
-                                ConstraintLocatorBuilder locator) {
+                                ConstraintLocatorBuilder locator,
+                                PreparedOverloadBuilder *preparedOverload) {
   assert(!type->hasUnboundGenericType());
 
   if (!type->hasTypeParameter())
     return type;
 
-  return TypeOpener(replacements, locator, *this)
+  return TypeOpener(replacements, locator, preparedOverload, *this)
       .doIt(type, TypePosition::Invariant);
 }
 
 Type ConstraintSystem::openPackExpansionType(PackExpansionType *expansion,
                                              ArrayRef<OpenedType> replacements,
-                                             ConstraintLocatorBuilder locator) {
+                                             ConstraintLocatorBuilder locator,
+                                             PreparedOverloadBuilder *preparedOverload) {
   auto patternType =
-      openType(expansion->getPatternType(), replacements, locator);
-  auto shapeType = openType(expansion->getCountType(), replacements, locator);
+      openType(expansion->getPatternType(), replacements, locator,
+               preparedOverload);
+  auto shapeType = openType(expansion->getCountType(), replacements, locator,
+                            preparedOverload);
 
   auto openedPackExpansion = PackExpansionType::get(patternType, shapeType);
 
-  auto known = OpenedPackExpansionTypes.find(openedPackExpansion);
-  if (known != OpenedPackExpansionTypes.end())
-    return known->second;
+  // FIXME: It's silly that we need to do this. The whole concept of
+  // "opening" pack expansions is broken.
+  {
+    if (preparedOverload) {
+      for (auto change : preparedOverload->Changes) {
+        if (change.Kind == PreparedOverload::Change::OpenedPackExpansionType &&
+            change.PackExpansion.TheExpansion == openedPackExpansion)
+          return change.PackExpansion.TypeVar;
+      }
+    }
+
+    auto known = OpenedPackExpansionTypes.find(openedPackExpansion);
+    if (known != OpenedPackExpansionTypes.end())
+      return known->second;
+  }
 
   auto *expansionLoc = getConstraintLocator(locator.withPathElement(
       LocatorPathElt::PackExpansionType(openedPackExpansion)));
 
-  auto *expansionVar = createTypeVariable(expansionLoc, TVO_PackExpansion);
+  auto *expansionVar = createTypeVariable(expansionLoc, TVO_PackExpansion,
+                                          preparedOverload);
 
   // This constraint is important to make sure that pack expansion always
   // has a binding and connect pack expansion var to any type variables
   // that appear in pattern and shape types.
-  addUnsolvedConstraint(Constraint::create(*this, ConstraintKind::FallbackType,
-                                           expansionVar, openedPackExpansion,
-                                           expansionLoc));
-
-  recordOpenedPackExpansionType(openedPackExpansion, expansionVar);
+  auto *c = Constraint::create(*this, ConstraintKind::FallbackType,
+                               expansionVar, openedPackExpansion,
+                               expansionLoc);
+  if (preparedOverload)
+    preparedOverload->addedConstraint(c);
+  else
+    addUnsolvedConstraint(c);
+
+  recordOpenedPackExpansionType(openedPackExpansion, expansionVar,
+                                preparedOverload);
   return expansionVar;
 }
 
 void ConstraintSystem::recordOpenedPackExpansionType(PackExpansionType *expansion,
-                                                     TypeVariableType *expansionVar) {
+                                                     TypeVariableType *expansionVar,
+                                                     PreparedOverloadBuilder *preparedOverload) {
+  if (preparedOverload) {
+    ASSERT(PreparingOverload);
+    preparedOverload->openedPackExpansionType(expansion, expansionVar);
+    return;
+  }
+
+  ASSERT(!PreparingOverload);
+
   bool inserted = OpenedPackExpansionTypes.insert({expansion, expansionVar}).second;
   ASSERT(inserted);
 
@@ -359,11 +515,13 @@ Type ConstraintSystem::openOpaqueType(OpaqueTypeArchetypeType *opaque,
 
   SmallVector<OpenedType, 4> replacements;
   openGeneric(DC, opaqueDecl->getOpaqueInterfaceGenericSignature(),
-              opaqueLocator, replacements);
+              opaqueLocator, replacements, /*preparedOverload=*/nullptr);
 
-  recordOpenedTypes(opaqueLocatorKey, replacements);
+  recordOpenedTypes(opaqueLocatorKey, replacements,
+                    /*preparedOverload=*/nullptr);
 
-  return openType(opaque->getInterfaceType(), replacements, locator);
+  return openType(opaque->getInterfaceType(), replacements, locator,
+                  /*preparedOverload=*/nullptr);
 }
 
 Type ConstraintSystem::openOpaqueType(Type type, ContextualTypePurpose context,
@@ -432,19 +590,24 @@ FunctionType *ConstraintSystem::openFunctionType(
        AnyFunctionType *funcType,
        ConstraintLocatorBuilder locator,
        SmallVectorImpl<OpenedType> &replacements,
-       DeclContext *outerDC) {
+       DeclContext *outerDC,
+       PreparedOverloadBuilder *preparedOverload) {
   if (auto *genericFn = funcType->getAs<GenericFunctionType>()) {
     auto signature = genericFn->getGenericSignature();
-    openGenericParameters(outerDC, signature, replacements, locator);
+    openGenericParameters(outerDC, signature, replacements, locator,
+                          preparedOverload);
 
     openGenericRequirements(outerDC, signature,
                             /*skipProtocolSelfConstraint=*/false, locator,
                             [&](Type type) -> Type {
-                              return openType(type, replacements, locator);
-                            });
+                              return openType(type, replacements, locator,
+                                              preparedOverload);
+                            }, preparedOverload);
 
     funcType = substGenericArgs(genericFn,
-        [&](Type type) { return openType(type, replacements, locator); });
+        [&](Type type) {
+          return openType(type, replacements, locator, preparedOverload);
+        });
   }
 
   return funcType->castTo<FunctionType>();
@@ -602,8 +765,7 @@ ClosureIsolatedByPreconcurrency::operator()(const ClosureExpr *expr) const {
 
 Type ConstraintSystem::getUnopenedTypeOfReference(
     VarDecl *value, Type baseType, DeclContext *UseDC,
-    ConstraintLocator *locator, bool wantInterfaceType,
-    bool adjustForPreconcurrency) {
+    ConstraintLocator *locator, bool wantInterfaceType) {
   Type requestedType;
   if (Type type = getTypeIfAvailable(value)) {
     requestedType = type;
@@ -622,14 +784,6 @@ Type ConstraintSystem::getUnopenedTypeOfReference(
   if (auto *expansion = requestedType->getAs<PackExpansionType>())
     requestedType = expansion->getPatternType();
 
-  // Adjust the type for concurrency if requested.
-  if (adjustForPreconcurrency) {
-    requestedType = adjustVarTypeForConcurrency(
-        requestedType, value, UseDC,
-        GetClosureType{*this},
-        ClosureIsolatedByPreconcurrency{*this});
-  }
-
   // If we're dealing with contextual types, and we referenced this type from
   // a different context, map the type.
   if (!wantInterfaceType && requestedType->hasArchetype()) {
@@ -651,8 +805,17 @@ Type ConstraintSystem::getUnopenedTypeOfReference(
 }
 
 void ConstraintSystem::recordOpenedType(
-    ConstraintLocator *locator, ArrayRef<OpenedType> openedTypes) {
-  bool inserted = OpenedTypes.insert({locator, openedTypes}).second;
+    ConstraintLocator *locator, ArrayRef<OpenedType> replacements,
+    PreparedOverloadBuilder *preparedOverload) {
+  if (preparedOverload) {
+    ASSERT(PreparingOverload);
+    preparedOverload->openedTypes(replacements);
+    return;
+  }
+
+  ASSERT(!PreparingOverload);
+
+  bool inserted = OpenedTypes.insert({locator, replacements}).second;
   ASSERT(inserted);
 
   if (solverState)
@@ -661,33 +824,32 @@ void ConstraintSystem::recordOpenedType(
 
 void ConstraintSystem::recordOpenedTypes(
        ConstraintLocatorBuilder locator,
-       SmallVectorImpl<OpenedType> &replacements,
+       const SmallVectorImpl<OpenedType> &replacements,
+       PreparedOverloadBuilder *preparedOverload,
        bool fixmeAllowDuplicates) {
   if (replacements.empty())
     return;
 
   // If the last path element is an archetype or associated type, ignore it.
   SmallVector<LocatorPathElt, 2> pathElts;
-  auto anchor = locator.getLocatorParts(pathElts);
+  (void) locator.getLocatorParts(pathElts);
   if (!pathElts.empty() &&
       pathElts.back().getKind() == ConstraintLocator::GenericParameter)
     return;
 
-  // If the locator is empty, ignore it.
-  if (!anchor && pathElts.empty())
-    return;
-
   ConstraintLocator *locatorPtr = getConstraintLocator(locator);
   assert(locatorPtr && "No locator for opened types?");
 
-  OpenedType* openedTypes
-    = Allocator.Allocate<OpenedType>(replacements.size());
-  std::copy(replacements.begin(), replacements.end(), openedTypes);
-
   // FIXME: Get rid of fixmeAllowDuplicates.
-  if (!fixmeAllowDuplicates || OpenedTypes.count(locatorPtr) == 0)
+  if (!fixmeAllowDuplicates || OpenedTypes.count(locatorPtr) == 0) {
+    OpenedType *openedTypes
+      = Allocator.Allocate<OpenedType>(replacements.size());
+    std::copy(replacements.begin(), replacements.end(), openedTypes);
+
     recordOpenedType(
-      locatorPtr, llvm::ArrayRef(openedTypes, replacements.size()));
+      locatorPtr, llvm::ArrayRef(openedTypes, replacements.size()),
+      preparedOverload);
+  }
 }
 
 /// Determine how many levels of argument labels should be removed from the
@@ -745,9 +907,12 @@ unsigned constraints::getNumApplications(bool hasAppliedSelf,
 /// Replaces property wrapper types in the parameter list of the given function type
 /// with the wrapped-value or projected-value types (depending on argument label).
 static FunctionType *
-unwrapPropertyWrapperParameterTypes(ConstraintSystem &cs, AbstractFunctionDecl *funcDecl,
-                                    FunctionRefInfo functionRefInfo, FunctionType *functionType,
-                                    ConstraintLocatorBuilder locator) {
+unwrapPropertyWrapperParameterTypes(ConstraintSystem &cs,
+                                    AbstractFunctionDecl *funcDecl,
+                                    FunctionRefInfo functionRefInfo,
+                                    FunctionType *functionType,
+                                    ConstraintLocatorBuilder locator,
+                                    PreparedOverloadBuilder *preparedOverload) {
   // Only apply property wrappers to unapplied references to functions.
   if (!functionRefInfo.isUnapplied())
     return functionType;
@@ -783,14 +948,15 @@ unwrapPropertyWrapperParameterTypes(ConstraintSystem &cs, AbstractFunctionDecl *
     }
 
     auto *loc = cs.getConstraintLocator(locator);
-    auto *wrappedType = cs.createTypeVariable(loc, 0);
+    auto *wrappedType = cs.createTypeVariable(loc, 0, preparedOverload);
     auto paramType = paramTypes[i].getParameterType();
     auto paramLabel = paramTypes[i].getLabel();
     auto paramInternalLabel = paramTypes[i].getInternalLabel();
     adjustedParamTypes.push_back(AnyFunctionType::Param(
         wrappedType, paramLabel, ParameterTypeFlags(), paramInternalLabel));
-    cs.applyPropertyWrapperToParameter(paramType, wrappedType, paramDecl, argLabel,
-                                       ConstraintKind::Equal, loc, loc);
+    cs.applyPropertyWrapperToParameter(
+        paramType, wrappedType, paramDecl, argLabel, ConstraintKind::Equal,
+        loc, loc, preparedOverload);
   }
 
   return FunctionType::get(adjustedParamTypes, functionType->getResult(),
@@ -805,16 +971,22 @@ static bool isRequirementOrWitness(const ConstraintLocatorBuilder &locator) {
 
 FunctionType *ConstraintSystem::adjustFunctionTypeForConcurrency(
     FunctionType *fnType, Type baseType, ValueDecl *decl, DeclContext *dc,
-    unsigned numApplies, bool isMainDispatchQueue, ArrayRef<OpenedType> replacements,
+    unsigned numApplies, bool isMainDispatchQueue, bool openGlobalActorType,
     ConstraintLocatorBuilder locator) {
 
   auto *adjustedTy = swift::adjustFunctionTypeForConcurrency(
       fnType, decl, dc, numApplies, isMainDispatchQueue, GetClosureType{*this},
       ClosureIsolatedByPreconcurrency{*this}, [&](Type type) {
-        if (replacements.empty())
+        if (!type->hasTypeParameter())
+          return type;
+
+        // FIXME: This should be handled elsewhere.
+        if (!openGlobalActorType)
           return type;
 
-        return openType(type, replacements, locator);
+        auto replacements = getOpenedTypes(getConstraintLocator(locator));
+        ASSERT(!replacements.empty());
+        return openType(type, replacements, locator, /*preparedOverload=*/nullptr);
       });
 
   // Infer @Sendable for global actor isolated function types under the
@@ -849,19 +1021,27 @@ FunctionType *ConstraintSystem::adjustFunctionTypeForConcurrency(
       } else if (numApplies < decl->getNumCurryLevels() &&
                  decl->hasCurriedSelf() ) {
         auto shouldMarkMemberTypeSendable = [&]() {
-          // Static member types are @Sendable on both levels because
-          // they only capture a metatype "base" that is always Sendable.
-          // For example, `(S.Type) -> () -> Void`.
-          if (!decl->isInstanceMember())
-            return true;
+          Type capturedBaseType = baseType;
+
+          if (!decl->isInstanceMember()) {
+            // Static member types are Sendable when the metatype of their
+            // base type is Sendable, because they capture that metatype.
+            // For example, `(S.Type) -> () -> Void`.
+            if (!capturedBaseType)
+              capturedBaseType = decl->getDeclContext()->getSelfTypeInContext();
+
+            if (!capturedBaseType->is<AnyMetatypeType>())
+              capturedBaseType = MetatypeType::get(capturedBaseType);
+          } else if (capturedBaseType) {
+            // For instance members we need to check whether instance type
+            // is Sendable because @Sendable function values cannot capture
+            // non-Sendable values (base instance type in this case).
+            // For example, `(C) -> () -> Void` where `C` should be Sendable
+            // for the inner function type to be Sendable as well.
+            capturedBaseType = capturedBaseType->getMetatypeInstanceType();
+          }
 
-          // For instance members we need to check whether instance type
-          // is Sendable because @Sendable function values cannot capture
-          // non-Sendable values (base instance type in this case).
-          // For example, `(C) -> () -> Void` where `C` should be Sendable
-          // for the inner function type to be Sendable as well.
-          return baseType &&
-                 baseType->getMetatypeInstanceType()->isSendableType();
+          return capturedBaseType && capturedBaseType->isSendableType();
         };
 
         auto referenceTy = adjustedTy->getResult()->castTo<FunctionType>();
@@ -917,55 +1097,42 @@ static Type replaceParamErrorTypeByPlaceholder(Type type, ValueDecl *value, bool
     }
   }
   assert(newParams.size() == declParams.size());
-  return FunctionType::get(newParams, funcType->getResult());
+  return FunctionType::get(newParams, funcType->getResult(),
+                           funcType->getExtInfo());
 }
 
-DeclReferenceType
-ConstraintSystem::getTypeOfReference(ValueDecl *value,
-                                     FunctionRefInfo functionRefInfo,
-                                     ConstraintLocatorBuilder locator,
-                                     DeclContext *useDC) {
+std::pair<Type, Type>
+ConstraintSystem::getTypeOfReferencePre(OverloadChoice choice,
+                                        DeclContext *useDC,
+                                        ConstraintLocatorBuilder locator,
+                                        PreparedOverloadBuilder *preparedOverload) {
+  auto *value = choice.getDecl();
+
+  ASSERT(!!preparedOverload == PreparingOverload);
+
   if (value->getDeclContext()->isTypeContext() && isa<FuncDecl>(value)) {
     // Unqualified lookup can find operator names within nominal types.
     auto func = cast<FuncDecl>(value);
     assert(func->isOperator() && "Lookup should only find operators");
 
-    SmallVector<OpenedType, 4> replacements;
+    SmallVector<OpenedType, 2> replacements;
 
     AnyFunctionType *funcType = func->getInterfaceType()
         ->castTo<AnyFunctionType>();
     auto openedType = openFunctionType(
-        funcType, locator, replacements, func->getDeclContext());
+        funcType, locator, replacements, func->getDeclContext(),
+        preparedOverload);
 
     // If we opened up any type variables, record the replacements.
-    recordOpenedTypes(locator, replacements);
-
-    // If this is a method whose result type is dynamic Self, replace
-    // DynamicSelf with the actual object type.
-    if (func->getResultInterfaceType()->hasDynamicSelfType()) {
-      auto params = openedType->getParams();
-      assert(params.size() == 1);
-      Type selfTy = params.front().getPlainType()->getMetatypeInstanceType();
-      openedType = openedType->replaceCovariantResultType(selfTy, 2)
-                        ->castTo<FunctionType>();
-    }
-
-    auto origOpenedType = openedType;
-    if (!isRequirementOrWitness(locator)) {
-      unsigned numApplies = getNumApplications(/*hasAppliedSelf*/ false,
-                                               functionRefInfo);
-      openedType = adjustFunctionTypeForConcurrency(
-          origOpenedType, /*baseType=*/Type(), func, useDC, numApplies, false,
-          replacements, locator);
-    }
+    recordOpenedTypes(locator, replacements, preparedOverload);
 
-    // The reference implicitly binds 'self'.
-    return {origOpenedType, openedType,
-            origOpenedType->getResult(), openedType->getResult(), Type()};
+    return {openedType, Type()};
   }
 
   // Unqualified reference to a local or global function.
   if (auto funcDecl = dyn_cast<AbstractFunctionDecl>(value)) {
+    auto functionRefInfo = choice.getFunctionRefInfo();
+
     SmallVector<OpenedType, 4> replacements;
 
     auto funcType = funcDecl->getInterfaceType()->castTo<AnyFunctionType>();
@@ -973,20 +1140,12 @@ ConstraintSystem::getTypeOfReference(ValueDecl *value,
         funcDecl, /*isCurriedInstanceReference=*/false, functionRefInfo);
 
     auto openedType = openFunctionType(funcType, locator, replacements,
-                                       funcDecl->getDeclContext())
+                                       funcDecl->getDeclContext(),
+                                       preparedOverload)
                           ->removeArgumentLabels(numLabelsToRemove);
     openedType = unwrapPropertyWrapperParameterTypes(
         *this, funcDecl, functionRefInfo, openedType->castTo<FunctionType>(),
-        locator);
-
-    auto origOpenedType = openedType;
-    if (!isRequirementOrWitness(locator)) {
-      unsigned numApplies = getNumApplications(/*hasAppliedSelf*/ false,
-                                               functionRefInfo);
-      openedType = adjustFunctionTypeForConcurrency(
-          origOpenedType->castTo<FunctionType>(), /*baseType=*/Type(), funcDecl,
-          useDC, numApplies, false, replacements, locator);
-    }
+        locator, preparedOverload);
 
     if (isForCodeCompletion() && openedType->hasError()) {
       // In code completion, replace error types by placeholder types so we can
@@ -996,9 +1155,9 @@ ConstraintSystem::getTypeOfReference(ValueDecl *value,
     }
 
     // If we opened up any type variables, record the replacements.
-    recordOpenedTypes(locator, replacements);
+    recordOpenedTypes(locator, replacements, preparedOverload);
 
-    return { origOpenedType, openedType, origOpenedType, openedType, Type() };
+    return {openedType, Type()};
   }
 
   // Unqualified reference to a type.
@@ -1013,18 +1172,18 @@ ConstraintSystem::getTypeOfReference(ValueDecl *value,
                                   /*isSpecialized=*/false);
     type = useDC->mapTypeIntoContext(type);
 
-    checkNestedTypeConstraints(*this, type, locator);
+    checkNestedTypeConstraints(*this, type, locator, preparedOverload);
 
     // Convert any placeholder types and open generics.
-    type = replaceInferableTypesWithTypeVars(type, locator);
+    type = replaceInferableTypesWithTypeVars(type, locator, preparedOverload);
 
     // Module types are not wrapped in metatypes.
     if (type->is<ModuleType>())
-      return { type, type, type, type, Type() };
+      return { type, Type() };
 
     // If it's a value reference, refer to the metatype.
     type = MetatypeType::get(type);
-    return { type, type, type, type, Type() };
+    return {type, Type()};
   }
 
   // Unqualified reference to a macro.
@@ -1035,36 +1194,146 @@ ConstraintSystem::getTypeOfReference(ValueDecl *value,
     SmallVector<OpenedType, 4> replacements;
     Type openedType = openFunctionType(
         macroType->castTo<AnyFunctionType>(), locator, replacements,
-        macro->getDeclContext());
+        macro->getDeclContext(),
+        preparedOverload);
 
     // If we opened up any type variables, record the replacements.
-    recordOpenedTypes(locator, replacements);
+    recordOpenedTypes(locator, replacements, preparedOverload);
 
     // FIXME: Should we use replaceParamErrorTypeByPlaceholder() here?
 
-    return { openedType, openedType, openedType, openedType, Type() };
+    return {openedType, Type()};
   }
 
   // Only remaining case: unqualified reference to a property.
   auto *varDecl = cast<VarDecl>(value);
 
   // Determine the type of the value, opening up that type if necessary.
-  // FIXME: @preconcurrency
   bool wantInterfaceType = !varDecl->getDeclContext()->isLocalContext();
   Type valueType =
       getUnopenedTypeOfReference(varDecl, Type(), useDC, 
                                  getConstraintLocator(locator),
                                  wantInterfaceType);
 
+  ASSERT(!valueType->hasUnboundGenericType() &&
+         !valueType->hasTypeParameter());
+
   Type thrownErrorType;
   if (auto accessor = varDecl->getEffectfulGetAccessor()) {
     thrownErrorType =
         accessor->getEffectiveThrownErrorType().value_or(Type());
   }
 
-  assert(!valueType->hasUnboundGenericType() &&
-         !valueType->hasTypeParameter());
-  return { valueType, valueType, valueType, valueType, thrownErrorType };
+  return {valueType, thrownErrorType};
+}
+
+DeclReferenceType
+ConstraintSystem::getTypeOfReferencePost(OverloadChoice choice,
+                                         DeclContext *useDC,
+                                         ConstraintLocatorBuilder locator,
+                                         Type openedType, Type thrownErrorType) {
+  auto *value = choice.getDecl();
+
+  if (value->getDeclContext()->isTypeContext() && isa<FuncDecl>(value)) {
+    auto *openedFnType = openedType->castTo<FunctionType>();
+
+    // Unqualified lookup can find operator names within nominal types.
+    auto func = cast<FuncDecl>(value);
+    assert(func->isOperator() && "Lookup should only find operators");
+
+    auto functionRefInfo = choice.getFunctionRefInfo();
+
+    auto origOpenedType = openedFnType;
+    if (!isRequirementOrWitness(locator)) {
+      unsigned numApplies = getNumApplications(/*hasAppliedSelf*/ false,
+                                               functionRefInfo);
+      openedFnType = adjustFunctionTypeForConcurrency(
+          origOpenedType, /*baseType=*/Type(), func, useDC, numApplies,
+          /*isMainDispatchQueue=*/false, /*openGlobalActorType=*/true, locator);
+    }
+
+    // If this is a method whose result type is dynamic Self, replace
+    // DynamicSelf with the actual object type. Repeat the adjustment
+    // for the original and adjusted types.
+    auto type = openedFnType;
+    if (openedFnType->hasDynamicSelfType()) {
+      auto params = openedFnType->getParams();
+      assert(params.size() == 1);
+      Type selfTy = params.front().getPlainType()->getMetatypeInstanceType();
+      type = openedFnType->replaceDynamicSelfType(selfTy)
+          ->castTo<FunctionType>();
+    }
+
+    auto origType = origOpenedType;
+    if (origOpenedType->hasDynamicSelfType()) {
+      auto params = origOpenedType->getParams();
+      assert(params.size() == 1);
+      Type selfTy = params.front().getPlainType()->getMetatypeInstanceType();
+      origType = origOpenedType->replaceDynamicSelfType(selfTy)
+          ->castTo<FunctionType>();
+    }
+
+    // The reference implicitly binds 'self'.
+    return {origOpenedType, openedType,
+            origType->getResult(), type->getResult(), Type()};
+  }
+
+  // Unqualified reference to a local or global function.
+  if (auto funcDecl = dyn_cast<AbstractFunctionDecl>(value)) {
+    auto origOpenedType = openedType;
+    if (!isRequirementOrWitness(locator)) {
+      unsigned numApplies = getNumApplications(/*hasAppliedSelf*/ false,
+                                               choice.getFunctionRefInfo());
+      openedType = adjustFunctionTypeForConcurrency(
+          origOpenedType->castTo<FunctionType>(), /*baseType=*/Type(), funcDecl,
+          useDC, numApplies, /*isMainDispatchQueue=*/false,
+          /*openGlobalActorType=*/true, locator);
+    }
+
+    return { origOpenedType, openedType, origOpenedType, openedType, Type() };
+  }
+
+  // Unqualified reference to a type.
+  if (isa<TypeDecl>(value)) {
+    return { openedType, openedType, openedType, openedType, Type() };
+  }
+
+  // Unqualified reference to a macro.
+  if (isa<MacroDecl>(value)) {
+    return { openedType, openedType, openedType, openedType, Type() };
+  }
+
+  // Only remaining case: unqualified reference to a property.
+  auto *varDecl = cast<VarDecl>(value);
+
+  // Adjust the type for concurrency.
+  auto origOpenedType = openedType;
+
+  if (!isRequirementOrWitness(locator)) {
+    openedType = adjustVarTypeForConcurrency(
+        openedType, varDecl, useDC,
+        GetClosureType{*this},
+        ClosureIsolatedByPreconcurrency{*this});
+  }
+
+  return { origOpenedType, openedType,
+           origOpenedType, openedType,
+           thrownErrorType };
+}
+
+DeclReferenceType
+ConstraintSystem::getTypeOfReference(OverloadChoice choice,
+                                     DeclContext *useDC,
+                                     ConstraintLocatorBuilder locator,
+                                     PreparedOverloadBuilder *preparedOverload) {
+  ASSERT(!!preparedOverload == PreparingOverload);
+
+  Type openedType, thrownErrorType;
+  std::tie(openedType, thrownErrorType) = getTypeOfReferencePre(
+      choice, useDC, locator, preparedOverload);
+
+  return getTypeOfReferencePost(choice, useDC, locator,
+                                openedType, thrownErrorType);
 }
 
 /// Bind type variables for archetypes that are determined from
@@ -1102,7 +1371,8 @@ static void bindArchetypesFromContext(
     ConstraintSystem &cs,
     DeclContext *outerDC,
     ConstraintLocator *locatorPtr,
-    ArrayRef<OpenedType> replacements) {
+    ArrayRef<OpenedType> replacements,
+    PreparedOverloadBuilder *preparedOverload) {
 
   auto bindPrimaryArchetype = [&](Type paramTy, Type contextTy) {
     // We might not have a type variable for this generic parameter
@@ -1113,7 +1383,7 @@ static void bindArchetypesFromContext(
     for (auto pair : replacements) {
       if (pair.first->isEqual(paramTy)) {
         cs.addConstraint(ConstraintKind::Bind, pair.second, contextTy,
-                         locatorPtr);
+                         locatorPtr, /*isFavored=*/false, preparedOverload);
         return;
       }
     }
@@ -1126,8 +1396,7 @@ static void bindArchetypesFromContext(
     if (parentDC->isTypeContext()) {
       if (parentDC != outerDC && parentDC->getSelfProtocolDecl()) {
         auto selfTy = parentDC->getSelfInterfaceType();
-        auto contextTy = cs.getASTContext().TheUnresolvedType;
-        bindPrimaryArchetype(selfTy, contextTy);
+        bindPrimaryArchetype(selfTy, ErrorType::get(cs.getASTContext()));
       }
       continue;
     }
@@ -1148,39 +1417,44 @@ void ConstraintSystem::openGeneric(
        DeclContext *outerDC,
        GenericSignature sig,
        ConstraintLocatorBuilder locator,
-       SmallVectorImpl<OpenedType> &replacements) {
+       SmallVectorImpl<OpenedType> &replacements,
+       PreparedOverloadBuilder *preparedOverload) {
   if (!sig)
     return;
 
-  openGenericParameters(outerDC, sig, replacements, locator);
+  openGenericParameters(outerDC, sig, replacements, locator, preparedOverload);
 
   // Add the requirements as constraints.
   openGenericRequirements(
       outerDC, sig, /*skipProtocolSelfConstraint=*/false, locator,
-      [&](Type type) { return openType(type, replacements, locator); });
+      [&](Type type) {
+        return openType(type, replacements, locator, preparedOverload);
+      }, preparedOverload);
 }
 
 void ConstraintSystem::openGenericParameters(DeclContext *outerDC,
                                              GenericSignature sig,
                                              SmallVectorImpl<OpenedType> &replacements,
-                                             ConstraintLocatorBuilder locator) {
+                                             ConstraintLocatorBuilder locator,
+                                             PreparedOverloadBuilder *preparedOverload) {
   ASSERT(sig);
   ASSERT(replacements.empty());
 
   // Create the type variables for the generic parameters.
   for (auto gp : sig.getGenericParams()) {
-    auto *typeVar = openGenericParameter(gp, locator);
+    auto *typeVar = openGenericParameter(gp, locator, preparedOverload);
     replacements.emplace_back(gp, typeVar);
   }
 
   auto *baseLocator = getConstraintLocator(
       locator.withPathElement(LocatorPathElt::OpenedGeneric(sig)));
 
-  bindArchetypesFromContext(*this, outerDC, baseLocator, replacements);
+  bindArchetypesFromContext(*this, outerDC, baseLocator, replacements, preparedOverload);
 }
 
 TypeVariableType *ConstraintSystem::openGenericParameter(GenericTypeParamType *parameter,
-                                                         ConstraintLocatorBuilder locator) {
+                                                         ConstraintLocatorBuilder locator,
+                                                         PreparedOverloadBuilder *preparedOverload) {
   auto *paramLocator = getConstraintLocator(
       locator.withPathElement(LocatorPathElt::GenericParameter(parameter)));
 
@@ -1192,20 +1466,21 @@ TypeVariableType *ConstraintSystem::openGenericParameter(GenericTypeParamType *p
   if (shouldAttemptFixes())
     options |= TVO_CanBindToHole;
 
-  return createTypeVariable(paramLocator, options);
+  return createTypeVariable(paramLocator, options, preparedOverload);
 }
 
 void ConstraintSystem::openGenericRequirements(
     DeclContext *outerDC, GenericSignature signature,
     bool skipProtocolSelfConstraint, ConstraintLocatorBuilder locator,
-    llvm::function_ref<Type(Type)> substFn) {
+    llvm::function_ref<Type(Type)> substFn,
+    PreparedOverloadBuilder *preparedOverload) {
   auto requirements = signature.getRequirements();
   for (unsigned pos = 0, n = requirements.size(); pos != n; ++pos) {
     auto openedGenericLoc =
       locator.withPathElement(LocatorPathElt::OpenedGeneric(signature));
     openGenericRequirement(outerDC, signature, pos, requirements[pos],
                            skipProtocolSelfConstraint, openedGenericLoc,
-                           substFn);
+                           substFn, preparedOverload);
   }
 }
 
@@ -1213,7 +1488,8 @@ void ConstraintSystem::openGenericRequirement(
     DeclContext *outerDC, GenericSignature signature,
     unsigned index, const Requirement &req,
     bool skipProtocolSelfConstraint, ConstraintLocatorBuilder locator,
-    llvm::function_ref<Type(Type)> substFn) {
+    llvm::function_ref<Type(Type)> substFn,
+    PreparedOverloadBuilder *preparedOverload) {
   std::optional<Requirement> openedReq;
   auto openedFirst = substFn(req.getFirstType());
 
@@ -1230,8 +1506,8 @@ void ConstraintSystem::openGenericRequirement(
 
     // Check whether the given type parameter has requirements that
     // prohibit it from using an isolated conformance.
-    if (typeParameterProhibitsIsolatedConformance(req.getFirstType(),
-                                                  signature))
+    if (signature &&
+        signature->prohibitsIsolatedConformance(req.getFirstType()))
       prohibitIsolatedConformance = true;
 
     openedReq = Requirement(kind, openedFirst, req.getSecondType());
@@ -1250,7 +1526,112 @@ void ConstraintSystem::openGenericRequirement(
   addConstraint(*openedReq,
                 locator.withPathElement(
                     LocatorPathElt::TypeParameterRequirement(index, kind)),
-                /*isFavored=*/false, prohibitIsolatedConformance);
+                /*isFavored=*/false, prohibitIsolatedConformance,
+                preparedOverload);
+}
+
+Type ConstraintSystem::getTypeOfMemberTypeReference(
+    Type baseObjTy, TypeDecl *typeDecl, ConstraintLocator *locator,
+    PreparedOverloadBuilder *preparedOverload) {
+  ASSERT(!isa<ModuleDecl>(typeDecl) && "Nested module?");
+
+  auto memberTy = TypeChecker::substMemberTypeWithBase(typeDecl, baseObjTy);
+
+  // If the member type is a constraint, e.g. because the
+  // reference is to a typealias with an underlying protocol
+  // or composition type, the member reference has existential
+  // type.
+  if (memberTy->isConstraintType())
+    memberTy = ExistentialType::get(memberTy);
+
+  checkNestedTypeConstraints(*this, memberTy, locator, preparedOverload);
+
+  // Convert any placeholders and open any generics.
+  memberTy = replaceInferableTypesWithTypeVars(
+      memberTy, locator, preparedOverload);
+
+  // Wrap it in a metatype, unless this is a value generic.
+  // 'substMemberTypeWithBase' returns the underlying value type
+  // of the value generic (e.g. 'Int').
+  if (!isa<GenericTypeParamDecl>(typeDecl) ||
+      !cast<GenericTypeParamDecl>(typeDecl)->isValue()) {
+    memberTy = MetatypeType::get(memberTy);
+  }
+
+  FunctionType::Param baseObjParam(baseObjTy);
+  return FunctionType::get({baseObjParam}, memberTy);
+}
+
+std::pair<Type, Type> ConstraintSystem::getOpenedStorageType(
+    Type baseTy, AbstractStorageDecl *value, DeclContext *useDC,
+    bool hasAppliedSelf, ArrayRef<OpenedType> replacements,
+    ConstraintLocator *locator, PreparedOverloadBuilder *preparedOverload) {
+  Type thrownErrorType;
+
+  if (auto accessor = value->getEffectfulGetAccessor()) {
+    thrownErrorType = accessor->getEffectiveThrownErrorType().value_or(Type());
+  }
+
+  // For a property, build a type (Self) -> PropType.
+  // For a subscript, build a type (Self) -> (Indices...) throws(?) -> ElementType.
+  //
+  // If the access is mutating, wrap the storage type in an lvalue type.
+  Type refType;
+  if (auto *subscript = dyn_cast<SubscriptDecl>(value)) {
+    auto elementTy = subscript->getElementInterfaceType();
+
+    if (doesStorageProduceLValue(subscript, baseTy, useDC, *this, locator))
+      elementTy = LValueType::get(elementTy);
+
+    auto indices = subscript->getInterfaceType()
+                            ->castTo<AnyFunctionType>()->getParams();
+
+    // Transfer the thrown error type into the subscript reference type,
+    // which will be used in the application.
+    FunctionType::ExtInfo info;
+    if (thrownErrorType) {
+      info = info.withThrows(true, thrownErrorType);
+      thrownErrorType = Type();
+    }
+
+    refType = FunctionType::get(indices, elementTy, info);
+  } else {
+    // Delay the adjustment for preconcurrency until after we've formed
+    // the function type for this kind of reference. Otherwise we will lose
+    // track of the adjustment in the formed function's return type.
+
+    refType = getUnopenedTypeOfReference(cast<VarDecl>(value), baseTy, useDC,
+                                         locator,
+                                         /*wantInterfaceType=*/true);
+  }
+
+  auto *outerDC = value->getDeclContext();
+  auto selfTy = outerDC->getSelfInterfaceType();
+
+  // If this is a reference to an instance member that applies self,
+  // where self is a value type and the base type is an lvalue, wrap it in an
+  // inout type.
+  auto selfFlags = ParameterTypeFlags();
+  if (value->isInstanceMember() && hasAppliedSelf &&
+      !outerDC->getDeclaredInterfaceType()->hasReferenceSemantics() &&
+      baseTy->is<LValueType>() &&
+      !selfTy->hasError())
+    selfFlags = selfFlags.withInOut(true);
+
+  // If the storage is generic, open the self and ref types.
+  selfTy = openType(selfTy, replacements, locator, preparedOverload);
+  refType = openType(refType, replacements, locator, preparedOverload);
+
+  if (thrownErrorType) {
+    thrownErrorType = openType(thrownErrorType, replacements, locator,
+                               preparedOverload);
+  }
+
+  FunctionType::Param selfParam(selfTy, Identifier(), selfFlags);
+
+  FunctionType::ExtInfo info;
+  return std::make_pair(FunctionType::get({selfParam}, refType, info),
+                        thrownErrorType);
 }
 
 /// Add the constraint on the type used for the 'Self' type for a member
@@ -1264,19 +1645,23 @@ void ConstraintSystem::openGenericRequirement(
 /// \param selfTy The instance type of the context in which the member is
 /// declared.
 static void addSelfConstraint(ConstraintSystem &cs, Type objectTy, Type selfTy,
-                              ConstraintLocatorBuilder locator){
+                              ConstraintLocatorBuilder locator,
+                              PreparedOverloadBuilder *preparedOverload) {
   assert(!selfTy->is<ProtocolType>());
 
-  // Otherwise, use a subtype constraint for classes to cope with inheritance.
+  // Otherwise, use a subtype constraint for classes to cope with
+  // inheritance.
   if (selfTy->getClassOrBoundGenericClass()) {
     cs.addConstraint(ConstraintKind::Subtype, objectTy, selfTy,
-                     cs.getConstraintLocator(locator));
+                     cs.getConstraintLocator(locator),
+                     /*isFavored=*/false, preparedOverload);
     return;
   }
 
   // Otherwise, the types must be equivalent.
   cs.addConstraint(ConstraintKind::Bind, objectTy, selfTy,
-                   cs.getConstraintLocator(locator));
+                   cs.getConstraintLocator(locator), /*isFavored=*/false,
+                   preparedOverload);
 }
 
 Type constraints::getDynamicSelfReplacementType(
@@ -1375,61 +1760,20 @@ static bool isExistentialMemberAccessWithExplicitBaseExpression(
 }
 
 Type ConstraintSystem::getMemberReferenceTypeFromOpenedType(
-    Type &openedType, Type baseObjTy, ValueDecl *value, DeclContext *outerDC,
-    ConstraintLocator *locator, bool hasAppliedSelf, bool isDynamicLookup,
-    ArrayRef<OpenedType> replacements) {
-  Type type = openedType;
-
-  // Cope with dynamic 'Self'.
-  if (!outerDC->getSelfProtocolDecl()) {
-    const auto replacementTy =
-        getDynamicSelfReplacementType(baseObjTy, value, locator);
-
-    if (auto func = dyn_cast<AbstractFunctionDecl>(value)) {
-      if (func->hasDynamicSelfResult() &&
-          !baseObjTy->getOptionalObjectType()) {
-        type = type->replaceCovariantResultType(replacementTy, 2);
-      }
-    } else if (auto *decl = dyn_cast<SubscriptDecl>(value)) {
-      if (decl->getElementInterfaceType()->hasDynamicSelfType()) {
-        type = type->replaceCovariantResultType(replacementTy, 2);
-      }
-    } else if (auto *decl = dyn_cast<VarDecl>(value)) {
-      if (decl->getValueInterfaceType()->hasDynamicSelfType()) {
-        type = type->replaceCovariantResultType(replacementTy, 1);
-      }
-    }
-  }
+    Type type, Type baseObjTy, ValueDecl *value,
+    ConstraintLocator *locator, bool hasAppliedSelf, bool isDynamicLookup) {
+  if (isa<MacroDecl>(value) || type->is<ErrorType>())
+    return ErrorType::get(getASTContext());
 
-  // Check if we need to apply a layer of optionality to the uncurried type.
-  if (!isRequirementOrWitness(locator)) {
-    if (isDynamicLookup || value->getAttrs().hasAttribute<OptionalAttr>()) {
-      const auto applyOptionality = [&](FunctionType *fnTy) -> Type {
-        Type resultTy;
-        // Optional and dynamic subscripts are a special case, because the
-        // optionality is applied to the result type and not the type of the
-        // reference.
-        if (isa<SubscriptDecl>(value)) {
-          auto *innerFn = fnTy->getResult()->castTo<FunctionType>();
-          resultTy = FunctionType::get(
-              innerFn->getParams(),
-              OptionalType::get(innerFn->getResult()->getRValueType()),
-              innerFn->getExtInfo());
-        } else {
-          resultTy = OptionalType::get(fnTy->getResult()->getRValueType());
-        }
+  auto *outerDC = value->getDeclContext();
 
-        return FunctionType::get(fnTy->getParams(), resultTy,
-                                 fnTy->getExtInfo());
-      };
+  // Cope with dynamic 'Self'.
+  if (outerDC->getSelfClassDecl()) {
+    if (type->hasDynamicSelfType()) {
+      auto replacementTy = getDynamicSelfReplacementType(
+          baseObjTy, value, locator);
 
-      // FIXME: Refactor 'replaceCovariantResultType' not to rely on the passed
-      // uncurry level.
-      //
-      // This is done after handling dynamic 'Self' to make
-      // 'replaceCovariantResultType' work, so we have to transform both types.
-      openedType = applyOptionality(openedType->castTo<FunctionType>());
-      type = applyOptionality(type->castTo<FunctionType>());
+      type = type->replaceDynamicSelfType(replacementTy);
     }
   }
 
@@ -1452,8 +1796,8 @@ Type ConstraintSystem::getMemberReferenceTypeFromOpenedType(
           baseObjTy, value, locator, isDynamicLookup) &&
       // If there are no type variables, there were no references to 'Self'.
       type->hasTypeVariable()) {
-    auto selfGP = outerDC->getSelfInterfaceType();
-    ASSERT(selfGP->isEqual(replacements[0].first));
+    auto replacements = getOpenedTypes(locator);
+    ASSERT(replacements[0].first->isEqual(getASTContext().TheSelfType));
     auto openedTypeVar = replacements[0].second;
 
     type = typeEraseOpenedExistentialReference(type, baseObjTy, openedTypeVar,
@@ -1497,188 +1841,177 @@ Type ConstraintSystem::getMemberReferenceTypeFromOpenedType(
   return type;
 }
 
-DeclReferenceType ConstraintSystem::getTypeOfMemberReference(
-    Type baseTy, ValueDecl *value, DeclContext *useDC, bool isDynamicLookup,
-    FunctionRefInfo functionRefInfo, ConstraintLocator *locator,
-    SmallVectorImpl<OpenedType> *replacementsPtr) {
-  // Figure out the instance type used for the base.
-  Type resolvedBaseTy = getFixedTypeRecursive(baseTy, /*wantRValue=*/true);
-
-  // If the base is a module type, just use the type of the decl.
-  if (resolvedBaseTy->is<ModuleType>()) {
-    return getTypeOfReference(value, functionRefInfo, locator, useDC);
-  }
-
-  // Check to see if the self parameter is applied, in which case we'll want to
-  // strip it off later.
-  auto hasAppliedSelf = doesMemberRefApplyCurriedSelf(resolvedBaseTy, value);
-
-  auto baseObjTy = resolvedBaseTy->getMetatypeInstanceType();
-  FunctionType::Param baseObjParam(baseObjTy);
-
-  // Indicates whether this is a valid reference to a static member on a
-  // protocol metatype. Such a reference is only valid if performed through
-  // leading dot syntax e.g. `foo(.bar)` where implicit base is a protocol
-  // metatype and `bar` is static member declared in a protocol  or its
-  // extension.
-  bool isStaticMemberRefOnProtocol = false;
-  if (baseObjTy->isExistentialType() && value->isStatic() &&
-      locator->isLastElement<LocatorPathElt::UnresolvedMember>()) {
-    assert(resolvedBaseTy->is<MetatypeType>() &&
-           "Assumed base of unresolved member access must be a metatype");
-    isStaticMemberRefOnProtocol = true;
+static FunctionType *applyOptionality(ValueDecl *value, FunctionType *fnTy) {
+  Type resultTy;
+
+  // Optional and dynamic subscripts are a special case, because the
+  // optionality is applied to the result type and not the type of the
+  // reference.
+  if (isa<SubscriptDecl>(value)) {
+    auto *innerFn = fnTy->getResult()->castTo<FunctionType>();
+    resultTy = FunctionType::get(
+        innerFn->getParams(),
+        OptionalType::get(innerFn->getResult()->getRValueType()),
+        innerFn->getExtInfo());
+  } else {
+    resultTy = OptionalType::get(fnTy->getResult()->getRValueType());
   }
 
-  if (auto *typeDecl = dyn_cast<TypeDecl>(value)) {
-    assert(!isa<ModuleDecl>(typeDecl) && "Nested module?");
-
-    auto memberTy = TypeChecker::substMemberTypeWithBase(typeDecl, baseObjTy);
-
-    // If the member type is a constraint, e.g. because the
-    // reference is to a typealias with an underlying protocol
-    // or composition type, the member reference has existential
-    // type.
-    if (memberTy->isConstraintType())
-      memberTy = ExistentialType::get(memberTy);
+  return FunctionType::get(fnTy->getParams(), resultTy,
+                           fnTy->getExtInfo());
+}
 
-    checkNestedTypeConstraints(*this, memberTy, locator);
+std::pair<Type, Type>
+ConstraintSystem::getTypeOfMemberReferencePre(
+    OverloadChoice choice, DeclContext *useDC,
+    ConstraintLocator *locator,
+    PreparedOverloadBuilder *preparedOverload) {
+  ASSERT(!!preparedOverload == PreparingOverload);
 
-    // Convert any placeholders and open any generics.
-    memberTy = replaceInferableTypesWithTypeVars(memberTy, locator);
+  auto *value = choice.getDecl();
+  auto functionRefInfo = choice.getFunctionRefInfo();
 
-    // Wrap it in a metatype.
-    memberTy = MetatypeType::get(memberTy);
+  // Figure out the instance type used for the base.
+  auto baseTy = choice.getBaseType();
+  Type baseRValueTy = baseTy->getRValueType();
+  auto baseObjTy = baseRValueTy->getMetatypeInstanceType();
 
-    auto openedType = FunctionType::get({baseObjParam}, memberTy);
-    return { openedType, openedType, memberTy, memberTy, Type() };
+  if (baseObjTy->is<ModuleType>()) {
+    return getTypeOfReferencePre(choice, useDC, locator, preparedOverload);
   }
 
-  if (isa<AbstractFunctionDecl>(value) || isa<EnumElementDecl>(value)) {
-    if (value->getInterfaceType()->is<ErrorType>()) {
-      auto genericErrorTy = ErrorType::get(getASTContext());
-      return { genericErrorTy, genericErrorTy, genericErrorTy, genericErrorTy, Type() };
-    }
+  Type openedType;
+  Type thrownErrorType;
+
+  if (auto *typeDecl = dyn_cast<TypeDecl>(value)) {
+    openedType = getTypeOfMemberTypeReference(baseObjTy, typeDecl,
+                                              locator, preparedOverload);
+    return {openedType, thrownErrorType};
   }
 
   // Figure out the declaration context to use when opening this type.
   DeclContext *innerDC = value->getInnermostDeclContext();
   DeclContext *outerDC = value->getDeclContext();
 
+  auto genericSig = innerDC->getGenericSignatureOfContext();
+
   // Open the type of the generic function or member of a generic type.
-  Type openedType;
-  SmallVector<OpenedType, 4> localReplacements;
-  auto &replacements = replacementsPtr ? *replacementsPtr : localReplacements;
+  SmallVector<OpenedType, 4> replacements;
 
   // If we have a generic signature, open the parameters. We delay opening
   // requirements to allow contextual types to affect the situation.
-  auto genericSig = innerDC->getGenericSignatureOfContext();
-  if (genericSig)
-    openGenericParameters(outerDC, genericSig, replacements, locator);
+  if (genericSig) {
+    openGenericParameters(outerDC, genericSig, replacements, locator,
+                          preparedOverload);
+  }
+
+  // If we opened up any type variables, record the replacements. We do this
+  // up-front to allow requirement fix coalescing logic to work correctly with
+  // requirements imposed on base type (since that relies on being able to
+  // find the recorded opened type). We then make the array immutable for the
+  // following logic to ensure they don't attempt to add any additional opened
+  // types.
+  recordOpenedTypes(locator, replacements, preparedOverload);
+
+  // Check to see if the self parameter is applied, in which case we'll want to
+  // strip it off later.
+  auto hasAppliedSelf = doesMemberRefApplyCurriedSelf(baseRValueTy, value);
+
+  if (isa<AbstractFunctionDecl>(value) ||
+      isa<EnumElementDecl>(value) ||
+      isa<MacroDecl>(value)) {
+    auto interfaceType = value->getInterfaceType();
+    if (interfaceType->is<ErrorType>() || isa<MacroDecl>(value))
+      return { interfaceType, Type() };
+
+    if (outerDC->getSelfClassDecl()) {
+      if (isa<ConstructorDecl>(value)) {
+        interfaceType = interfaceType->withCovariantResultType();
+      }
+    }
 
-  Type thrownErrorType;
-  if (isa<AbstractFunctionDecl>(value) || isa<EnumElementDecl>(value)) {
     // This is the easy case.
-    openedType = value->getInterfaceType()->castTo<AnyFunctionType>();
+    openedType = interfaceType->castTo<AnyFunctionType>();
 
     if (auto *genericFn = openedType->getAs<GenericFunctionType>()) {
       openedType = substGenericArgs(genericFn,
-          [&](Type type) { return openType(type, replacements, locator); });
+          [&](Type type) {
+            return openType(type, replacements, locator, preparedOverload);
+          });
     }
   } else {
-    // If the storage has a throwing getter, save the thrown error type..
-    auto storage = cast<AbstractStorageDecl>(value);
-    if (auto accessor = storage->getEffectfulGetAccessor()) {
-      thrownErrorType = accessor->getEffectiveThrownErrorType().value_or(Type());
-    }
+    auto *storage = cast<AbstractStorageDecl>(value);
 
-    // For a property, build a type (Self) -> PropType.
-    // For a subscript, build a type (Self) -> (Indices...) throws(?) -> ElementType.
-    //
-    // If the access is mutating, wrap the storage type in an lvalue type.
-    Type refType;
-    if (auto *subscript = dyn_cast<SubscriptDecl>(value)) {
-      auto elementTy = subscript->getElementInterfaceType();
-
-      if (doesStorageProduceLValue(subscript, baseTy, useDC, *this, locator))
-        elementTy = LValueType::get(elementTy);
-
-      auto indices = subscript->getInterfaceType()
-                              ->castTo<AnyFunctionType>()->getParams();
+    std::tie(openedType, thrownErrorType) = getOpenedStorageType(
+        baseTy, storage, useDC, hasAppliedSelf, replacements, locator,
+        preparedOverload);
+  }
 
-      // Transfer the thrown error type into the subscript reference type,
-      // which will be used in the application.
-      FunctionType::ExtInfo info;
-      if (thrownErrorType) {
-        info = info.withThrows(true, thrownErrorType);
-        thrownErrorType = Type();
-      }
+  ASSERT(!openedType->hasTypeParameter());
 
-      refType = FunctionType::get(indices, elementTy, info);
-    } else {
-      // Delay the adjustment for preconcurrency until after we've formed
-      // the function type for this kind of reference. Otherwise we will lose
-      // track of the adjustment in the formed function's return type.
+  // Remove argument labels if this is an unapplied reference.
+  unsigned numRemovedArgumentLabels = getNumRemovedArgumentLabels(
+      value, /*isCurriedInstanceReference*/ !hasAppliedSelf, functionRefInfo);
+  openedType = openedType->removeArgumentLabels(numRemovedArgumentLabels);
 
-      refType = getUnopenedTypeOfReference(cast<VarDecl>(value), baseTy, useDC,
-                                           locator,
-                                           /*wantInterfaceType=*/true,
-                                           /*adjustForPreconcurrency=*/false);
+  // Adjust for C++ inline namespaces.
+  if (const auto *FT = openedType->getAs<FunctionType>()) {
+    auto openedParams = FT->getParams();
+    assert(openedParams.size() == 1);
+    auto param = openedParams.front();
+
+    Type selfObjTy = param.getPlainType();
+    bool wasMetaType = false;
+    if (param.getPlainType()->is<MetatypeType>()) {
+      selfObjTy = param.getPlainType()->getMetatypeInstanceType();
+      wasMetaType = true;
     }
-
-    auto selfTy = outerDC->getSelfInterfaceType();
-
-    // If this is a reference to an instance member that applies self,
-    // where self is a value type and the base type is an lvalue, wrap it in an
-    // inout type.
-    auto selfFlags = ParameterTypeFlags();
-    if (value->isInstanceMember() && hasAppliedSelf &&
-        !outerDC->getDeclaredInterfaceType()->hasReferenceSemantics() &&
-        baseTy->is<LValueType>() &&
-        !selfTy->hasError())
-      selfFlags = selfFlags.withInOut(true);
-
-    // If the storage is generic, open the self and ref types.
-    if (genericSig) {
-      selfTy = openType(selfTy, replacements, locator);
-      refType = openType(refType, replacements, locator);
-
-      if (thrownErrorType)
-        thrownErrorType = openType(thrownErrorType, replacements, locator);
+    if (auto *objectTyNominal = baseObjTy->getAs<NominalType>()) {
+      if (auto *selfTyNominal = selfObjTy->getAs<NominalType>())
+        if (auto newSelfTy =
+                swift::stripInlineNamespaces(objectTyNominal, selfTyNominal))
+          openedType = FunctionType::get(
+              param.withType(wasMetaType ? Type(MetatypeType::get(newSelfTy))
+                                         : Type(newSelfTy)),
+              FT->getResult(), FT->getExtInfo());
     }
-    FunctionType::Param selfParam(selfTy, Identifier(), selfFlags);
-
-    FunctionType::ExtInfo info;
-    openedType = FunctionType::get({selfParam}, refType, info);
   }
-  assert(!openedType->hasTypeParameter());
-
-  unsigned numRemovedArgumentLabels = getNumRemovedArgumentLabels(
-      value, /*isCurriedInstanceReference*/ !hasAppliedSelf, functionRefInfo);
-
-  openedType = openedType->removeArgumentLabels(numRemovedArgumentLabels);
 
-  // If we are looking at a member of an existential, open the existential.
   Type baseOpenedTy = baseObjTy;
 
-  if (isStaticMemberRefOnProtocol) {
-    // In diagnostic mode, let's not try to replace base type
-    // if there is already a known issue associated with this
-    // reference e.g. it might be incorrect initializer call
-    // or result type is invalid.
-    if (!(shouldAttemptFixes() && hasFixFor(getConstraintLocator(locator)))) {
-      if (auto concreteSelf =
-              getConcreteReplacementForProtocolSelfType(value)) {
-        // Concrete type replacing `Self` could be generic, so we need
-        // to make sure that it's opened before use.
-        baseOpenedTy = openType(concreteSelf, replacements, locator);
-        baseObjTy = baseOpenedTy;
+  // If we are looking at a member of an existential, open the existential.
+  if (baseObjTy->isExistentialType()) {
+    if (value->isStatic() &&
+        locator->isLastElement<LocatorPathElt::UnresolvedMember>()) {
+      // Indicates whether this is a valid reference to a static member on a
+      // protocol metatype. Such a reference is only valid if performed through
+      // leading dot syntax e.g. `foo(.bar)` where implicit base is a protocol
+      // metatype and `bar` is static member declared in a protocol  or its
+      // extension.
+      assert(baseRValueTy->is<MetatypeType>() &&
+             "Assumed base of unresolved member access must be a metatype");
+
+      // In diagnostic mode, let's not try to replace base type
+      // if there is already a known issue associated with this
+      // reference e.g. it might be incorrect initializer call
+      // or result type is invalid.
+      if (!(shouldAttemptFixes() && hasFixFor(getConstraintLocator(locator)))) {
+        if (auto concreteSelf =
+                getConcreteReplacementForProtocolSelfType(value)) {
+          // Concrete type replacing `Self` could be generic, so we need
+          // to make sure that it's opened before use.
+          baseOpenedTy = openType(concreteSelf, replacements, locator,
+                                  preparedOverload);
+        }
       }
+    } else {
+      // Open the existential.
+      auto openedArchetype =
+          ExistentialArchetypeType::get(baseObjTy->getCanonicalType());
+      recordOpenedExistentialType(getConstraintLocator(locator), openedArchetype,
+                                  preparedOverload);
+      baseOpenedTy = openedArchetype;
     }
-  } else if (baseObjTy->isExistentialType()) {
-    auto openedArchetype =
-        ExistentialArchetypeType::get(baseObjTy->getCanonicalType());
-    recordOpenedExistentialType(getConstraintLocator(locator), openedArchetype);
-    baseOpenedTy = openedArchetype;
   }
 
   // Constrain the 'self' object type.
@@ -1691,9 +2024,10 @@ DeclReferenceType ConstraintSystem::getTypeOfMemberReference(
     // conformance constraint because we wouldn't have found the declaration
     // if it didn't conform.
     addConstraint(ConstraintKind::Bind, baseOpenedTy, selfObjTy,
-                  getConstraintLocator(locator));
-  } else if (!isDynamicLookup) {
-    addSelfConstraint(*this, baseOpenedTy, selfObjTy, locator);
+                  getConstraintLocator(locator), /*isFavored=*/false,
+                  preparedOverload);
+  } else if (choice.getKind() != OverloadChoiceKind::DeclViaDynamic) {
+    addSelfConstraint(*this, baseOpenedTy, selfObjTy, locator, preparedOverload);
   }
 
   // Open generic requirements after self constraint has been
@@ -1706,42 +2040,67 @@ DeclReferenceType ConstraintSystem::getTypeOfMemberReference(
     openGenericRequirements(
         outerDC, genericSig,
         /*skipProtocolSelfConstraint=*/true, locator,
-        [&](Type type) { return openType(type, replacements, locator); });
+        [&](Type type) {
+          return openType(type, replacements, locator, preparedOverload);
+        }, preparedOverload);
   }
 
+  // Unwrap property wrappers if this is an unapplied reference.
   if (auto *funcDecl = dyn_cast<AbstractFunctionDecl>(value)) {
-    auto *fullFunctionType = openedType->getAs<AnyFunctionType>();
+    if (functionRefInfo.isUnapplied()) {
+      auto *fullFunctionType = openedType->getAs<AnyFunctionType>();
+
+      auto *functionType = fullFunctionType->getResult()->getAs<FunctionType>();
+      functionType = unwrapPropertyWrapperParameterTypes(
+          *this, funcDecl, functionRefInfo, functionType,
+          locator, preparedOverload);
+      openedType =
+          FunctionType::get(fullFunctionType->getParams(), functionType,
+                            fullFunctionType->getExtInfo());
+    }
+  }
 
-    // Strip off the 'self' parameter
-    auto *functionType = fullFunctionType->getResult()->getAs<FunctionType>();
-    functionType = unwrapPropertyWrapperParameterTypes(*this, funcDecl, functionRefInfo,
-                                                       functionType, locator);
-    // FIXME: Verify ExtInfo state is correct, not working by accident.
-    FunctionType::ExtInfo info;
+  return { openedType, thrownErrorType };
+}
+
+DeclReferenceType ConstraintSystem::getTypeOfMemberReferencePost(
+    OverloadChoice choice, DeclContext *useDC, ConstraintLocator *locator,
+    Type openedType, Type thrownErrorType) {
+  auto *value = choice.getDecl();
 
-    // We'll do other adjustment later, but we need to handle parameter
-    // isolation to avoid assertions.
-    if (fullFunctionType->getIsolation().isParameter())
-      info = info.withIsolation(FunctionTypeIsolation::forParameter());
+  // Figure out the instance type used for the base.
+  Type baseTy = choice.getBaseType();
+  Type baseRValueTy = baseTy->getRValueType();
+  Type baseObjTy = baseRValueTy->getMetatypeInstanceType();
+
+  if (baseObjTy->is<ModuleType>()) {
+    return getTypeOfReferencePost(choice, useDC, locator,
+                                  openedType, thrownErrorType);
+  }
 
-    openedType =
-        FunctionType::get(fullFunctionType->getParams(), functionType, info);
+  if (isa<TypeDecl>(value)) {
+    auto type = openedType->castTo<FunctionType>()->getResult();
+    return { openedType, openedType, type, type, Type() };
   }
 
+  auto hasAppliedSelf = doesMemberRefApplyCurriedSelf(baseRValueTy, value);
+
   // Adjust the opened type for concurrency.
   Type origOpenedType = openedType;
   if (isRequirementOrWitness(locator)) {
     // Don't adjust when doing witness matching, because that can cause cycles.
   } else if (isa<AbstractFunctionDecl>(value) || isa<EnumElementDecl>(value)) {
-    unsigned numApplies = getNumApplications(hasAppliedSelf, functionRefInfo);
+    unsigned numApplies = getNumApplications(
+        hasAppliedSelf, choice.getFunctionRefInfo());
     openedType = adjustFunctionTypeForConcurrency(
-        origOpenedType->castTo<FunctionType>(), resolvedBaseTy, value, useDC,
-        numApplies, isMainDispatchQueueMember(locator), replacements, locator);
+        origOpenedType->castTo<FunctionType>(), baseObjTy, value, useDC,
+        numApplies, isMainDispatchQueueMember(locator),
+        /*openGlobalActorType=*/true, locator);
   } else if (auto subscript = dyn_cast<SubscriptDecl>(value)) {
     openedType = adjustFunctionTypeForConcurrency(
-        origOpenedType->castTo<FunctionType>(), resolvedBaseTy, subscript,
-        useDC,
-        /*numApplies=*/2, /*isMainDispatchQueue=*/false, replacements, locator);
+        origOpenedType->castTo<FunctionType>(), baseObjTy, subscript, useDC,
+        /*numApplies=*/2, /*isMainDispatchQueue=*/false,
+        /*openGlobalActorType=*/true, locator);
   } else if (auto var = dyn_cast<VarDecl>(value)) {
     // Adjust the function's result type, since that's the Var's actual type.
     auto origFnType = origOpenedType->castTo<AnyFunctionType>();
@@ -1754,25 +2113,45 @@ DeclReferenceType ConstraintSystem::getTypeOfMemberReference(
                   origFnType->getParams(), resultTy, origFnType->getExtInfo());
   }
 
-  // Compute the type of the reference.
+  bool isDynamicLookup = (choice.getKind() == OverloadChoiceKind::DeclViaDynamic);
+
+  // Check if we need to apply a layer of optionality to the type.
+  if (!isRequirementOrWitness(locator)) {
+    if (isDynamicLookup || value->getAttrs().hasAttribute<OptionalAttr>()) {
+      openedType = applyOptionality(value, openedType->castTo<FunctionType>());
+      origOpenedType = applyOptionality(value, origOpenedType->castTo<FunctionType>());
+    }
+  }
+
+  // Handle DynamicSelfType and a couple of other things.
   Type type = getMemberReferenceTypeFromOpenedType(
-      openedType, baseObjTy, value, outerDC, locator, hasAppliedSelf,
-      isDynamicLookup, replacements);
+      openedType, baseObjTy, value, locator, hasAppliedSelf,
+      isDynamicLookup);
 
   // Do the same thing for the original type, if there can be any difference.
   Type origType = type;
   if (openedType.getPointer() != origOpenedType.getPointer()) {
     origType = getMemberReferenceTypeFromOpenedType(
-        origOpenedType, baseObjTy, value, outerDC, locator, hasAppliedSelf,
-        isDynamicLookup, replacements);
+        origOpenedType, baseObjTy, value, locator, hasAppliedSelf,
+        isDynamicLookup);
   }
 
-  // If we opened up any type variables, record the replacements.
-  recordOpenedTypes(locator, replacements);
-
   return { origOpenedType, openedType, origType, type, thrownErrorType };
 }
 
+DeclReferenceType ConstraintSystem::getTypeOfMemberReference(
+    OverloadChoice choice, DeclContext *useDC, ConstraintLocator *locator,
+    PreparedOverloadBuilder *preparedOverload) {
+  ASSERT(!!preparedOverload == PreparingOverload);
+
+  Type openedType, thrownErrorType;
+  std::tie(openedType, thrownErrorType)
+      = getTypeOfMemberReferencePre(choice, useDC, locator, preparedOverload);
+
+  return getTypeOfMemberReferencePost(
+      choice, useDC, locator, openedType, thrownErrorType);
+}
+
 Type ConstraintSystem::getEffectiveOverloadType(ConstraintLocator *locator,
                                                 const OverloadChoice &overload,
                                                 bool allowMembers,
@@ -1835,16 +2214,17 @@ Type ConstraintSystem::getEffectiveOverloadType(ConstraintLocator *locator,
     if (!allowMembers)
       return Type();
 
-    const auto withDynamicSelfResultReplaced = [&](Type type,
-                                                   unsigned uncurryLevel) {
-      const Type baseObjTy = overload.getBaseType()
-                                 ->getRValueType()
-                                 ->getMetatypeInstanceType()
-                                 ->lookThroughAllOptionalTypes();
+    auto getBaseObjectType = [&] () -> Type {
+      return overload.getBaseType()
+          ->getRValueType()
+          ->getMetatypeInstanceType()
+          ->lookThroughAllOptionalTypes();
+    };
 
-      return type->replaceCovariantResultType(
-          getDynamicSelfReplacementType(baseObjTy, decl, locator),
-          uncurryLevel);
+    auto withDynamicSelfResultReplaced = [&](Type type) {
+      return type->replaceDynamicSelfType(
+        getDynamicSelfReplacementType(
+          getBaseObjectType(), decl, locator));
     };
 
     SmallVector<OpenedType, 4> emptyReplacements;
@@ -1855,8 +2235,7 @@ Type ConstraintSystem::getEffectiveOverloadType(ConstraintLocator *locator,
                                    useDC, *this, locator))
         elementTy = LValueType::get(elementTy);
       else if (elementTy->hasDynamicSelfType()) {
-        elementTy = withDynamicSelfResultReplaced(elementTy,
-                                                  /*uncurryLevel=*/0);
+        elementTy = withDynamicSelfResultReplaced(elementTy);
       }
 
       // See ConstraintSystem::resolveOverload() -- optional and dynamic
@@ -1871,47 +2250,42 @@ Type ConstraintSystem::getEffectiveOverloadType(ConstraintLocator *locator,
       FunctionType::ExtInfo info;
       type = adjustFunctionTypeForConcurrency(
           FunctionType::get(indices, elementTy, info), overload.getBaseType(),
-          subscript, useDC,
-          /*numApplies=*/1, /*isMainDispatchQueue=*/false, emptyReplacements,
-          locator);
+          subscript, useDC, /*numApplies=*/1, /*isMainDispatchQueue=*/false,
+          /*openGlobalActorType=*/false, locator);
     } else if (auto var = dyn_cast<VarDecl>(decl)) {
       type = var->getValueInterfaceType();
       if (doesStorageProduceLValue(
               var, overload.getBaseType(), useDC, *this, locator)) {
         type = LValueType::get(type);
       } else if (type->hasDynamicSelfType()) {
-        type = withDynamicSelfResultReplaced(type, /*uncurryLevel=*/0);
+        type = withDynamicSelfResultReplaced(type);
       }
       type = adjustVarTypeForConcurrency(
           type, var, useDC, GetClosureType{*this},
           ClosureIsolatedByPreconcurrency{*this});
     } else if (isa<AbstractFunctionDecl>(decl) || isa<EnumElementDecl>(decl)) {
-      if (decl->isInstanceMember() &&
-          (!overload.getBaseType() ||
-           (!overload.getBaseType()->getAnyNominal() &&
-            !overload.getBaseType()->is<ExistentialType>())))
-        return Type();
+      if (decl->isInstanceMember()) {
+        auto baseTy = overload.getBaseType();
+        if (!baseTy)
+          return Type();
+
+        baseTy = baseTy->getRValueType();
+        if (!baseTy->getAnyNominal() && !baseTy->is<ExistentialType>() &&
+            !baseTy->is<OpaqueTypeArchetypeType>())
+          return Type();
+      }
+
+      if (isa<ConstructorDecl>(decl) &&
+          decl->getDeclContext()->getSelfClassDecl()) {
+        type = type->withCovariantResultType();
+      }
 
       // Cope with 'Self' returns.
-      if (!decl->getDeclContext()->getSelfProtocolDecl()) {
-        if (isa<AbstractFunctionDecl>(decl) &&
-            cast<AbstractFunctionDecl>(decl)->hasDynamicSelfResult()) {
-          if (!overload.getBaseType())
-            return Type();
-
-          if (!overload.getBaseType()->getOptionalObjectType()) {
-            // `Int??(0)` if we look through all optional types for `Self`
-            // we'll end up with incorrect type `Int?` for result because
-            // the actual result type is `Int??`.
-            if (isa<ConstructorDecl>(decl) && overload.getBaseType()
-                                                  ->getRValueType()
-                                                  ->getMetatypeInstanceType()
-                                                  ->getOptionalObjectType())
-              return Type();
-
-            type = withDynamicSelfResultReplaced(type, /*uncurryLevel=*/2);
-          }
-        }
+      if (type->hasDynamicSelfType()) {
+        if (!overload.getBaseType())
+          return Type();
+
+        type = withDynamicSelfResultReplaced(type);
       }
 
       auto hasAppliedSelf =
@@ -1921,9 +2295,9 @@ Type ConstraintSystem::getEffectiveOverloadType(ConstraintLocator *locator,
 
       type = adjustFunctionTypeForConcurrency(
                  type->castTo<FunctionType>(), overload.getBaseType(), decl,
-                 useDC, numApplies,
-                 /*isMainDispatchQueue=*/false, emptyReplacements, locator)
-                 ->getResult();
+                 useDC, numApplies, /*isMainDispatchQueue=*/false,
+                 /*openGlobalActorType=*/false, locator)
+                    ->getResult();
     }
   }
 
@@ -2048,13 +2422,13 @@ void ConstraintSystem::bindOverloadType(const SelectedOverload &overload,
 
     if (auto *existential = paramTy->getAs<ExistentialType>()) {
       paramTy = existential->getSuperclass();
-      assert(isKnownKeyPathType(paramTy));
+      assert(paramTy->isKnownKeyPathType());
     }
 
     auto keyPathTy = paramTy->castTo<BoundGenericType>();
 
     auto *keyPathDecl = keyPathTy->getAnyNominal();
-    assert(isKnownKeyPathType(keyPathTy) &&
+    assert(keyPathTy->isKnownKeyPathType() &&
            "parameter is supposed to be a keypath");
 
     auto *keyPathLoc = getConstraintLocator(
@@ -2075,11 +2449,25 @@ void ConstraintSystem::bindOverloadType(const SelectedOverload &overload,
                            // FIXME: Should propagate name-as-written through.
                            : DeclNameRef(choice.getName());
 
-    addValueMemberConstraint(
-        LValueType::get(rootTy), memberName, memberTy, useDC,
-        isSubscriptRef ? FunctionRefInfo::doubleBaseNameApply()
-                       : FunctionRefInfo::unappliedBaseName(),
-        /*outerAlternatives=*/{}, keyPathLoc);
+    // Check the current depth of applied dynamic member lookups, if we've
+    // exceeded the limit then record a fix and set a hole for the member.
+    unsigned lookupDepth = [&]() {
+      auto path = keyPathLoc->getPath();
+      auto iter = path.begin();
+      (void)keyPathLoc->findFirst<LocatorPathElt::KeyPathDynamicMember>(iter);
+      return path.end() - iter;
+    }();
+    if (lookupDepth > ctx.TypeCheckerOpts.DynamicMemberLookupDepthLimit) {
+      (void)recordFix(TooManyDynamicMemberLookups::create(
+          *this, DeclNameRef(choice.getName()), locator));
+      recordTypeVariablesAsHoles(memberTy);
+    } else {
+      addValueMemberConstraint(
+          LValueType::get(rootTy), memberName, memberTy, useDC,
+          isSubscriptRef ? FunctionRefInfo::doubleBaseNameApply()
+                         : FunctionRefInfo::unappliedBaseName(),
+          /*outerAlternatives=*/{}, keyPathLoc);
+    }
 
     // In case of subscript things are more complicated comparing to "dot"
     // syntax, because we have to get "applicable function" constraint
@@ -2258,9 +2646,10 @@ isInvalidPartialApplication(ConstraintSystem &cs,
 /// checking semantics, compute the type of the reference.  For now, follow
 /// the lead of \c getTypeOfMemberReference and return a pair of
 /// the full opened type and the reference's type.
-static DeclReferenceType getTypeOfReferenceWithSpecialTypeCheckingSemantics(
+static Type getTypeOfReferenceWithSpecialTypeCheckingSemantics(
     ConstraintSystem &CS, ConstraintLocator *locator,
-    DeclTypeCheckingSemantics semantics) {
+    DeclTypeCheckingSemantics semantics,
+    PreparedOverloadBuilder *preparedOverload) {
   switch (semantics) {
   case DeclTypeCheckingSemantics::Normal:
     llvm_unreachable("Decl does not have special type checking semantics!");
@@ -2272,21 +2661,21 @@ static DeclReferenceType getTypeOfReferenceWithSpecialTypeCheckingSemantics(
     // be expressed in the type system currently.
     auto input = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::FunctionArgument),
-        TVO_CanBindToNoEscape);
+        TVO_CanBindToNoEscape, preparedOverload);
     auto output = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::FunctionResult),
-        TVO_CanBindToNoEscape);
+        TVO_CanBindToNoEscape, preparedOverload);
 
     FunctionType::Param inputArg(input,
                                  CS.getASTContext().getIdentifier("of"));
 
     CS.addConstraint(
         ConstraintKind::DynamicTypeOf, output, input,
-        CS.getConstraintLocator(locator, ConstraintLocator::DynamicType));
+        CS.getConstraintLocator(locator, ConstraintLocator::DynamicType),
+        /*isFavored=*/false, preparedOverload);
     // FIXME: Verify ExtInfo state is correct, not working by accident.
     FunctionType::ExtInfo info;
-    auto refType = FunctionType::get({inputArg}, output, info);
-    return {refType, refType, refType, refType, Type()};
+    return FunctionType::get({inputArg}, output, info);
   }
   case DeclTypeCheckingSemantics::WithoutActuallyEscaping: {
     // Proceed with a "WithoutActuallyEscaping" operation. The body closure
@@ -2294,22 +2683,31 @@ static DeclReferenceType getTypeOfReferenceWithSpecialTypeCheckingSemantics(
     // @escaping.
     auto noescapeClosure = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::FunctionArgument),
-        TVO_CanBindToNoEscape);
+        TVO_CanBindToNoEscape, preparedOverload);
     auto escapeClosure = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::FunctionArgument),
-        TVO_CanBindToNoEscape);
+        TVO_CanBindToNoEscape, preparedOverload);
     CS.addConstraint(ConstraintKind::EscapableFunctionOf, escapeClosure,
-                     noescapeClosure, CS.getConstraintLocator(locator));
+                     noescapeClosure, CS.getConstraintLocator(locator),
+                     /*isFavored=*/false, preparedOverload);
     auto result = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::FunctionResult),
-        TVO_CanBindToNoEscape);
+        TVO_CanBindToNoEscape, preparedOverload);
     auto thrownError = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::ThrownErrorType),
-        0);
+        0, preparedOverload);
     FunctionType::Param arg(escapeClosure);
+
+    auto bodyParamIsolation = FunctionTypeIsolation::forNonIsolated();
+    if (CS.getASTContext().LangOpts.hasFeature(
+            Feature::NonisolatedNonsendingByDefault)) {
+      bodyParamIsolation = FunctionTypeIsolation::forNonIsolatedCaller();
+    }
+
     auto bodyClosure = FunctionType::get(arg, result,
                                          FunctionType::ExtInfoBuilder()
                                              .withNoEscape(true)
+                                             .withIsolation(bodyParamIsolation)
                                              .withAsync(true)
                                              .withThrows(true, thrownError)
                                              .build());
@@ -2318,49 +2716,71 @@ static DeclReferenceType getTypeOfReferenceWithSpecialTypeCheckingSemantics(
       FunctionType::Param(bodyClosure, CS.getASTContext().getIdentifier("do")),
     };
 
-    auto refType = FunctionType::get(args, result,
-                                     FunctionType::ExtInfoBuilder()
-                                         .withNoEscape(false)
-                                         .withAsync(true)
-                                         .withThrows(true, thrownError)
-                                         .build());
-    return {refType, refType, refType, refType, Type()};
+    auto withoutEscapingIsolation = FunctionTypeIsolation::forNonIsolated();
+    if (CS.getASTContext().LangOpts.hasFeature(
+            Feature::NonisolatedNonsendingByDefault)) {
+      withoutEscapingIsolation = FunctionTypeIsolation::forNonIsolatedCaller();
+    }
+
+    return FunctionType::get(args, result,
+                             FunctionType::ExtInfoBuilder()
+                                 .withNoEscape(false)
+                                 .withIsolation(withoutEscapingIsolation)
+                                 .withAsync(true)
+                                 .withThrows(true, thrownError)
+                                 .build());
   }
   case DeclTypeCheckingSemantics::OpenExistential: {
     // The body closure receives a freshly-opened archetype constrained by the
     // existential type as its input.
     auto openedTy = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::FunctionArgument),
-        TVO_CanBindToNoEscape);
+        TVO_CanBindToNoEscape, preparedOverload);
     auto existentialTy = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::FunctionArgument),
-        TVO_CanBindToNoEscape);
+        TVO_CanBindToNoEscape, preparedOverload);
     CS.addConstraint(ConstraintKind::OpenedExistentialOf, openedTy,
-                     existentialTy, CS.getConstraintLocator(locator));
+                     existentialTy, CS.getConstraintLocator(locator),
+                     /*isFavored=*/false, preparedOverload);
     auto result = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::FunctionResult),
-        TVO_CanBindToNoEscape);
+        TVO_CanBindToNoEscape, preparedOverload);
     auto thrownError = CS.createTypeVariable(
         CS.getConstraintLocator(locator, ConstraintLocator::ThrownErrorType),
-        0);
+        0, preparedOverload);
     FunctionType::Param bodyArgs[] = {FunctionType::Param(openedTy)};
+
+    auto bodyParamIsolation = FunctionTypeIsolation::forNonIsolated();
+    if (CS.getASTContext().LangOpts.hasFeature(
+            Feature::NonisolatedNonsendingByDefault)) {
+      bodyParamIsolation = FunctionTypeIsolation::forNonIsolatedCaller();
+    }
+
     auto bodyClosure = FunctionType::get(bodyArgs, result,
                                          FunctionType::ExtInfoBuilder()
                                              .withNoEscape(true)
                                              .withThrows(true, thrownError)
+                                             .withIsolation(bodyParamIsolation)
                                              .withAsync(true)
                                              .build());
     FunctionType::Param args[] = {
       FunctionType::Param(existentialTy),
       FunctionType::Param(bodyClosure, CS.getASTContext().getIdentifier("do")),
     };
-    auto refType = FunctionType::get(args, result,
-                                     FunctionType::ExtInfoBuilder()
-                                         .withNoEscape(false)
-                                         .withThrows(true, thrownError)
-                                         .withAsync(true)
-                                         .build());
-    return {refType, refType, refType, refType, Type()};
+
+    auto openExistentialIsolation = FunctionTypeIsolation::forNonIsolated();
+    if (CS.getASTContext().LangOpts.hasFeature(
+            Feature::NonisolatedNonsendingByDefault)) {
+      openExistentialIsolation = FunctionTypeIsolation::forNonIsolatedCaller();
+    }
+
+    return FunctionType::get(args, result,
+                             FunctionType::ExtInfoBuilder()
+                                 .withNoEscape(false)
+                                 .withThrows(true, thrownError)
+                                 .withIsolation(openExistentialIsolation)
+                                 .withAsync(true)
+                                 .build());
   }
   }
 
@@ -2376,49 +2796,160 @@ void ConstraintSystem::recordResolvedOverload(ConstraintLocator *locator,
     recordChange(SolverTrail::Change::ResolvedOverload(locator));
 }
 
-void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
-                                       Type boundType, OverloadChoice choice,
-                                       DeclContext *useDC) {
-  // Determine the type to which we'll bind the overload set's type.
+void ConstraintSystem::replayChanges(
+    ConstraintLocator *locator,
+    PreparedOverload *preparedOverload) {
+  for (auto change : preparedOverload->getChanges()) {
+    switch (change.Kind) {
+    case PreparedOverload::Change::AddedTypeVariable:
+      addTypeVariable(change.TypeVar);
+      break;
+
+    case PreparedOverload::Change::AddedConstraint:
+      simplifyDisjunctionChoice(change.TheConstraint);
+      break;
+
+    case PreparedOverload::Change::AddedBindConstraint:
+      addConstraint(ConstraintKind::Bind,
+                    change.Bind.FirstType,
+                    change.Bind.SecondType,
+                    locator, /*isFavored=*/false);
+      break;
+
+    case PreparedOverload::Change::OpenedTypes: {
+      ArrayRef<OpenedType> replacements(
+          change.Replacements.Data,
+          change.Replacements.Count);
+
+      // FIXME: Get rid of this conditional.
+      if (getOpenedTypes(locator).empty())
+        recordOpenedType(locator, replacements);
+      break;
+    }
+
+    case PreparedOverload::Change::OpenedExistentialType: {
+      recordOpenedExistentialType(locator,
+                                  change.TheExistential);
+      break;
+    }
+
+    case PreparedOverload::Change::OpenedPackExpansionType:
+      recordOpenedPackExpansionType(
+          change.PackExpansion.TheExpansion,
+          change.PackExpansion.TypeVar);
+      break;
+
+    case PreparedOverload::Change::AppliedPropertyWrapper: {
+      Expr *anchor = getAsExpr(locator->getAnchor());
+      applyPropertyWrapper(anchor,
+          { Type(change.PropertyWrapper.WrapperType),
+            change.PropertyWrapper.InitKind });
+      break;
+    }
+
+    case PreparedOverload::Change::AddedFix:
+      recordFix(change.Fix.TheFix, change.Fix.Impact);
+      break;
+
+    case PreparedOverload::Change::RecordedNodeType:
+      setType(change.Node.Node, change.Node.TheType);
+      break;
+    }
+  }
+}
+
+/// Populate the prepared overload with all type variables and constraints
+/// that are to be introduced into the constraint system when this choice
+/// is taken.
+///
+/// Returns a pair consisting of the opened type, and the thrown error type.
+///
+/// FIXME: As a transitional mechanism, if preparedOverload is nullptr, this
+/// immediately performs all operations.
+std::pair<Type, Type>
+ConstraintSystem::prepareOverloadImpl(OverloadChoice choice,
+                                      DeclContext *useDC,
+                                      ConstraintLocator *locator,
+                                      PreparedOverloadBuilder *preparedOverload) {
+  // If we refer to a top-level decl with special type-checking semantics,
+  // handle it now.
+  auto semantics =
+      TypeChecker::getDeclTypeCheckingSemantics(choice.getDecl());
+  if (semantics != DeclTypeCheckingSemantics::Normal) {
+    auto openedType = getTypeOfReferenceWithSpecialTypeCheckingSemantics(
+        *this, locator, semantics, preparedOverload);
+    return {openedType, Type()};
+  } else if (choice.getBaseType()) {
+    return getTypeOfMemberReferencePre(choice, useDC, locator, preparedOverload);
+  } else {
+    return getTypeOfReferencePre(choice, useDC, locator, preparedOverload);
+  }
+}
+
+PreparedOverload *ConstraintSystem::prepareOverload(OverloadChoice choice,
+                                                    DeclContext *useDC,
+                                                    ConstraintLocator *locator) {
+  ASSERT(!PreparingOverload);
+  PreparingOverload = true;
+
+  PreparedOverloadBuilder builder;
   Type openedType;
-  Type adjustedOpenedType;
-  Type refType;
-  Type adjustedRefType;
-  Type thrownErrorTypeOnAccess;
+  Type thrownErrorType;
+  std::tie(openedType, thrownErrorType) = prepareOverloadImpl(
+      choice, useDC, locator, &builder);
+
+  PreparingOverload = false;
+
+  size_t count = builder.Changes.size();
+  auto size = PreparedOverload::totalSizeToAlloc<PreparedOverload::Change>(count);
+  auto mem = Allocator.Allocate(size, alignof(PreparedOverload));
+
+  return new (mem) PreparedOverload(openedType, thrownErrorType, builder.Changes);
+}
+
+void ConstraintSystem::resolveOverload(OverloadChoice choice, DeclContext *useDC,
+                                       ConstraintLocator *locator, Type boundType,
+                                       PreparedOverload *preparedOverload) {
+  // Determine the type to which we'll bind the overload set's type.
+  DeclReferenceType declRefType;
 
-  switch (auto kind = choice.getKind()) {
+  switch (choice.getKind()) {
   case OverloadChoiceKind::Decl:
   case OverloadChoiceKind::DeclViaBridge:
   case OverloadChoiceKind::DeclViaDynamic:
   case OverloadChoiceKind::DeclViaUnwrappedOptional:
   case OverloadChoiceKind::DynamicMemberLookup:
   case OverloadChoiceKind::KeyPathDynamicMemberLookup: {
-    // If we refer to a top-level decl with special type-checking semantics,
-    // handle it now.
-    const auto semantics =
+    Type openedType, thrownErrorType;
+
+    if (preparedOverload) {
+      replayChanges(locator, preparedOverload);
+
+      openedType = preparedOverload->getOpenedType();
+      thrownErrorType = preparedOverload->getThrownErrorType();
+    } else {
+      std::tie(openedType, thrownErrorType) = prepareOverloadImpl(
+          choice, useDC, locator, nullptr);
+    }
+
+    auto semantics =
         TypeChecker::getDeclTypeCheckingSemantics(choice.getDecl());
-    DeclReferenceType declRefType;
     if (semantics != DeclTypeCheckingSemantics::Normal) {
-      declRefType = getTypeOfReferenceWithSpecialTypeCheckingSemantics(
-          *this, locator, semantics);
-    } else if (auto baseTy = choice.getBaseType()) {
-      // Retrieve the type of a reference to the specific declaration choice.
-      assert(!baseTy->hasTypeParameter());
-
-      declRefType = getTypeOfMemberReference(
-          baseTy, choice.getDecl(), useDC,
-          (kind == OverloadChoiceKind::DeclViaDynamic),
-          choice.getFunctionRefInfo(), locator, nullptr);
+      declRefType.openedType = openedType;
+      declRefType.adjustedOpenedType = openedType;
+      declRefType.referenceType = openedType;
+      declRefType.adjustedReferenceType = openedType;
+      declRefType.thrownErrorTypeOnAccess = thrownErrorType;
     } else {
-      declRefType = getTypeOfReference(
-          choice.getDecl(), choice.getFunctionRefInfo(), locator, useDC);
+      if (choice.getBaseType()) {
+        declRefType = getTypeOfMemberReferencePost(
+            choice, useDC, locator, openedType, thrownErrorType);
+      } else {
+        declRefType = getTypeOfReferencePost(
+            choice, useDC, locator, openedType, thrownErrorType);
+      }
     }
 
-    openedType = declRefType.openedType;
-    adjustedOpenedType = declRefType.adjustedOpenedType;
-    refType = declRefType.referenceType;
-    adjustedRefType = declRefType.adjustedReferenceType;
-    thrownErrorTypeOnAccess = declRefType.thrownErrorTypeOnAccess;
     break;
   }
 
@@ -2426,14 +2957,16 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
     if (auto lvalueTy = choice.getBaseType()->getAs<LValueType>()) {
       // When the base of a tuple lvalue, the member is always an lvalue.
       auto tuple = lvalueTy->getObjectType()->castTo<TupleType>();
-      adjustedRefType = tuple->getElementType(choice.getTupleIndex())->getRValueType();
-      adjustedRefType = LValueType::get(adjustedRefType);
+      declRefType.adjustedReferenceType =
+          LValueType::get(
+              tuple->getElementType(choice.getTupleIndex())->getRValueType());
     } else {
       // When the base is a tuple rvalue, the member is always an rvalue.
       auto tuple = choice.getBaseType()->castTo<TupleType>();
-      adjustedRefType = tuple->getElementType(choice.getTupleIndex())->getRValueType();
+      declRefType.adjustedReferenceType =
+          tuple->getElementType(choice.getTupleIndex())->getRValueType();
     }
-    refType = adjustedRefType;
+    declRefType.referenceType = declRefType.adjustedReferenceType;
     break;
 
   case OverloadChoiceKind::MaterializePack: {
@@ -2443,18 +2976,18 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
     // In the future, _if_ the syntax allows for multiple expansions
     // this code would have to be adjusted to project l-value from the
     // base type just like TupleIndex does.
-    adjustedRefType =
+    declRefType.adjustedReferenceType =
         getPatternTypeOfSingleUnlabeledPackExpansionTuple(choice.getBaseType());
-    refType = adjustedRefType;
+    declRefType.referenceType = declRefType.adjustedReferenceType;
     break;
   }
 
   case OverloadChoiceKind::ExtractFunctionIsolation: {
     // The type of `.isolation` is `(any Actor)?`
     auto actor = getASTContext().getProtocol(KnownProtocolKind::Actor);
-    adjustedRefType =
+    declRefType.adjustedReferenceType =
         OptionalType::get(actor->getDeclaredExistentialType());
-    refType = adjustedRefType;
+    declRefType.referenceType = declRefType.adjustedReferenceType;
     break;
   }
 
@@ -2485,11 +3018,11 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
     // FIXME: Verify ExtInfo state is correct, not working by accident.
     FunctionType::ExtInfo fullInfo;
     auto fullTy = FunctionType::get({baseParam}, subscriptTy, fullInfo);
-    openedType = fullTy;
-    adjustedOpenedType = fullTy;
+    declRefType.openedType = fullTy;
+    declRefType.adjustedOpenedType = fullTy;
     // FIXME: @preconcurrency
-    refType = subscriptTy;
-    adjustedRefType = subscriptTy;
+    declRefType.referenceType = subscriptTy;
+    declRefType.adjustedReferenceType = subscriptTy;
 
     // Increase the score so that actual subscripts get preference.
     // ...except if we're solving for code completion and the index expression
@@ -2502,8 +3035,9 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
     break;
   }
   }
-  assert(!refType->hasTypeParameter() && "Cannot have a dependent type here");
-  assert(!adjustedRefType->hasTypeParameter() &&
+  assert(!declRefType.referenceType->hasTypeParameter() &&
+         "Cannot have a dependent type here");
+  assert(!declRefType.adjustedReferenceType->hasTypeParameter() &&
          "Cannot have a dependent type here");
 
   if (auto *decl = choice.getDeclOrNull()) {
@@ -2523,7 +3057,7 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
       if (locator->isResultOfKeyPathDynamicMemberLookup() ||
           locator->isKeyPathSubscriptComponent()) {
         // Subscript type has a format of (Self[.Type) -> (Arg...) -> Result
-        auto declTy = adjustedOpenedType->castTo<FunctionType>();
+        auto declTy = declRefType.adjustedOpenedType->castTo<FunctionType>();
         auto subscriptTy = declTy->getResult()->castTo<FunctionType>();
         // If we have subscript, each of the arguments has to conform to
         // Hashable, because it would be used as a component inside key path.
@@ -2595,7 +3129,7 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
 
       // The default type of the #isolation builtin macro is `(any Actor)?`
       if (macro->getBuiltinKind() == BuiltinMacroKind::IsolationMacro) {
-        auto *fnType = openedType->getAs<FunctionType>();
+        auto *fnType = declRefType.openedType->getAs<FunctionType>();
         auto actor = getASTContext().getProtocol(KnownProtocolKind::Actor);
         addConstraint(
             ConstraintKind::Defaultable, fnType->getResult(),
@@ -2607,14 +3141,20 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
 
   // If accessing this declaration could throw an error, record this as a
   // potential throw site.
-  if (thrownErrorTypeOnAccess) {
+  if (declRefType.thrownErrorTypeOnAccess) {
     recordPotentialThrowSite(
-        PotentialThrowSite::PropertyAccess, thrownErrorTypeOnAccess, locator);
+        PotentialThrowSite::PropertyAccess,
+        declRefType.thrownErrorTypeOnAccess,
+        locator);
   }
 
   // Note that we have resolved this overload.
   auto overload = SelectedOverload{
-      choice, openedType, adjustedOpenedType, refType, adjustedRefType,
+      choice,
+      declRefType.openedType,
+      declRefType.adjustedOpenedType,
+      declRefType.referenceType,
+      declRefType.adjustedReferenceType,
       boundType};
   recordResolvedOverload(locator, overload);
 
@@ -2622,15 +3162,14 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
   bindOverloadType(overload, boundType, locator, useDC);
 
   if (isDebugMode()) {
-    PrintOptions PO;
-    PO.PrintTypesForDebugging = true;
+    PrintOptions PO = PrintOptions::forDebugging();
 
     auto &log = llvm::errs();
     log.indent(solverState ? solverState->getCurrentIndent() : 2);
     log << "(overload set choice binding ";
     boundType->print(log, PO);
     log << " := ";
-    adjustedRefType->print(log, PO);
+    declRefType.adjustedReferenceType->print(log, PO);
 
     auto openedAtLoc = getOpenedTypes(locator);
     if (!openedAtLoc.empty()) {
@@ -2662,8 +3201,9 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
                   OverloadChoiceKind::DeclViaDynamic)) {
 
         // Strip curried 'self' parameters.
-        auto fromTy = openedType->castTo<AnyFunctionType>()->getResult();
-        auto toTy = refType;
+        auto fromTy = declRefType.openedType
+            ->castTo<AnyFunctionType>()->getResult();
+        auto toTy = declRefType.referenceType;
         if (!doesMemberRefApplyCurriedSelf(baseTy, decl)) {
           toTy = toTy->castTo<AnyFunctionType>()->getResult();
         }
@@ -2683,7 +3223,8 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
       increaseScore(SK_Unavailable, locator);
 
     // If the declaration is from a module that hasn't been imported, note that.
-    if (getASTContext().LangOpts.hasFeature(Feature::MemberImportVisibility)) {
+    if (getASTContext().LangOpts.hasFeature(Feature::MemberImportVisibility,
+                                            /*allowMigration=*/true)) {
       if (!useDC->isDeclImported(decl))
         increaseScore(SK_MissingImport, locator);
     }
diff --git a/lib/Serialization/DeclTypeRecordNodes.def b/lib/Serialization/DeclTypeRecordNodes.def
index 3ffd7b345a76f..0ee58b5d3e668 100644
--- a/lib/Serialization/DeclTypeRecordNodes.def
+++ b/lib/Serialization/DeclTypeRecordNodes.def
@@ -213,12 +213,12 @@ OTHER(DERIVATIVE_FUNCTION_CONFIGURATION, 154)
 
 OTHER(ERROR_FLAG, 155)
 OTHER(ABI_ONLY_COUNTERPART, 156)
+OTHER(DECL_NAME_REF, 157)
 
 TRAILING_INFO(CONDITIONAL_SUBSTITUTION)
 TRAILING_INFO(CONDITIONAL_SUBSTITUTION_COND)
 
 OTHER(LIFETIME_DEPENDENCE, 160)
-
 TRAILING_INFO(INHERITED_PROTOCOLS)
 
 #ifndef DECL_ATTR
diff --git a/lib/Serialization/Deserialization.cpp b/lib/Serialization/Deserialization.cpp
index 321da2c961c77..8869182e094d7 100644
--- a/lib/Serialization/Deserialization.cpp
+++ b/lib/Serialization/Deserialization.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -181,6 +181,8 @@ const char InvalidEnumValueError::ID = '\0';
 void InvalidEnumValueError::anchor() {}
 const char ConformanceXRefError::ID = '\0';
 void ConformanceXRefError::anchor() {}
+const char InavalidAvailabilityDomainError::ID = '\0';
+void InavalidAvailabilityDomainError::anchor() {}
 
 /// Skips a single record in the bitstream.
 ///
@@ -253,9 +255,7 @@ ModularizationError::diagnose(const ModuleFile *MF,
     llvm_unreachable("Unhandled ModularizationError::Kind in switch.");
   };
 
-  auto inFlight = diagnoseError(errorKind);
-  inFlight.limitBehavior(limit);
-  inFlight.flush();
+  diagnoseError(errorKind).limitBehavior(limit);
 
   // We could pass along the `path` information through notes.
   // However, for a top-level decl a path would just duplicate the
@@ -458,8 +458,9 @@ void ModuleFile::outputDiagnosticInfo(llvm::raw_ostream &os) const {
 
 static std::optional<swift::AccessorKind> getActualAccessorKind(uint8_t raw) {
   switch (serialization::AccessorKind(raw)) {
-#define ACCESSOR(ID) \
-  case serialization::AccessorKind::ID: return swift::AccessorKind::ID;
+#define ACCESSOR(ID, KEYWORD)                                                  \
+  case serialization::AccessorKind::ID:                                        \
+    return swift::AccessorKind::ID;
 #include "swift/AST/AccessorKinds.def"
   }
 
@@ -1003,13 +1004,13 @@ ProtocolConformanceDeserializer::readNormalProtocolConformanceXRef(
   auto error = llvm::make_error<ConformanceXRefError>(
                  nominal->getName(), proto->getName(), module);
 
-  if (!MF.enableExtendedDeserializationRecovery()) {
-    error = llvm::handleErrors(std::move(error),
-      [&](const ConformanceXRefError &error) -> llvm::Error {
-        error.diagnose(&MF);
-        return llvm::make_error<ConformanceXRefError>(std::move(error));
-      });
-  }
+  // Diagnose the root error here.
+  error = llvm::handleErrors(std::move(error),
+    [&](const ConformanceXRefError &error) -> llvm::Error {
+      error.diagnose(&MF);
+      return llvm::make_error<ConformanceXRefError>(std::move(error));
+    });
+
   return error;
 }
 
@@ -1056,11 +1057,14 @@ ProtocolConformanceDeserializer::readNormalProtocolConformance(
   auto globalActorType = globalActorTypeOrError.get();
 
   TypeExpr *globalActorTypeExpr = nullptr;
-  if (globalActorType)
+  if (globalActorType) {
     globalActorTypeExpr = TypeExpr::createImplicit(globalActorType, ctx);
+    rawOptions |=
+        static_cast<unsigned>(ProtocolConformanceFlags::GlobalActorIsolated);
+  }
 
   auto conformance = ctx.getNormalConformance(
-      conformingType, proto, SourceLoc(), dc,
+      conformingType, proto, SourceLoc(), /*inheritedTypeRepr=*/nullptr, dc,
       ProtocolConformanceState::Incomplete,
       ProtocolConformanceOptions(rawOptions, globalActorTypeExpr));
 
@@ -1720,7 +1724,7 @@ ModuleFile::getGenericSignatureChecked(serialization::GenericSignatureID ID) {
   }
   default:
     // Not a generic signature; no way to recover.
-    fatal(llvm::make_error<InvalidRecordKindError>(recordID));
+    return diagnoseFatal(llvm::make_error<InvalidRecordKindError>(recordID));
   }
 
   // If we've already deserialized this generic signature, start over to return
@@ -2824,6 +2828,12 @@ ModuleFile::resolveCrossReference(ModuleID MID, uint32_t pathLen) {
   if (M)
     return diagnoseFatal();
 
+  if (values.size() > 1) {
+    // Apply shadowing filtering after other local filters so we don't rule out
+    // valid candidates shadowed by invalid ones.
+    removeShadowedDecls(values, baseModule);
+  }
+
   // When all is said and done, we should have a single value here to return.
   if (values.size() != 1) {
     return llvm::make_error<XRefError>("result is ambiguous", pathTrace,
@@ -3187,6 +3197,7 @@ getActualReadImplKind(unsigned rawKind) {
   CASE(Address)
   CASE(Read)
   CASE(Read2)
+  CASE(Borrow)
 #undef CASE
   }
   return std::nullopt;
@@ -3206,6 +3217,7 @@ getActualWriteImplKind(unsigned rawKind) {
   CASE(MutableAddress)
   CASE(Modify)
   CASE(Modify2)
+  CASE(Mutate)
 #undef CASE
   }
   return std::nullopt;
@@ -3225,6 +3237,7 @@ getActualReadWriteImplKind(unsigned rawKind) {
   CASE(Modify2)
   CASE(StoredWithDidSet)
   CASE(InheritedWithDidSet)
+  CASE(Mutate)
 #undef CASE
   }
   return std::nullopt;
@@ -3433,7 +3446,7 @@ class DeclDeserializer {
     if (auto *typeDecl = decl.dyn_cast<TypeDecl *>())
       typeDecl->setInherited(inherited);
     else
-      decl.get<ExtensionDecl *>()->setInherited(inherited);
+      cast<ExtensionDecl *>(decl)->setInherited(inherited);
   }
 
   llvm::Error finishRecursiveAttrs(Decl *decl, DeclAttribute *attrs);
@@ -3455,17 +3468,10 @@ class DeclDeserializer {
     if (IsInvalid) {
       decl->setInvalidBit();
 
-      DeclName name;
-      if (auto *VD = dyn_cast<ValueDecl>(decl)) {
-        name = VD->getName();
-      }
-
       auto diagId = MF.allowCompilerErrors()
                         ? diag::serialization_allowing_invalid_decl
                         : diag::serialization_invalid_decl;
-      ctx.Diags.diagnose(SourceLoc(), diagId, name,
-                         decl->getDescriptiveKind(),
-                         MF.getAssociatedModule()->getNameStr());
+      ctx.Diags.diagnose(SourceLoc(), diagId, decl, MF.getAssociatedModule());
     }
 
     if (DAttrs)
@@ -3494,6 +3500,58 @@ class DeclDeserializer {
   /// offsets in \c customAttrOffsets.
   llvm::Error deserializeCustomAttrs();
 
+  DeclNameRef deserializeDeclNameRefIfPresent() {
+    using namespace decls_block;
+
+    SmallVector<uint64_t, 64> scratch;
+    StringRef blobData;
+
+    BCOffsetRAII restoreOffset(MF.DeclTypeCursor);
+    llvm::BitstreamEntry entry =
+        MF.fatalIfUnexpected(MF.DeclTypeCursor.advance());
+
+    unsigned recordID = MF.fatalIfUnexpected(
+        MF.DeclTypeCursor.readRecord(entry.ID, scratch, &blobData));
+
+    if (recordID != DECL_NAME_REF)
+      // This is normal--it just means there isn't a DeclNameRef here.
+      return { DeclNameRef() };
+
+    bool isCompoundName;
+    bool hasModuleSelector;
+    ArrayRef<uint64_t> rawPieceIDs;
+
+    DeclNameRefLayout::readRecord(scratch, isCompoundName, hasModuleSelector,
+                                  rawPieceIDs);
+    restoreOffset.cancel();
+
+    Identifier moduleSelector;
+    DeclBaseName baseName;
+
+    unsigned restIndex = 0;
+
+    ASSERT(rawPieceIDs.size() > 0);
+    if (hasModuleSelector) {
+      moduleSelector = MF.getIdentifier(rawPieceIDs[restIndex]);
+      restIndex++;
+    }
+
+    ASSERT(rawPieceIDs.size() > restIndex);
+    baseName = MF.getDeclBaseName(rawPieceIDs[restIndex]);
+    restIndex++;
+
+    if (isCompoundName) {
+      SmallVector<Identifier, 8> argLabels;
+      for (auto rawArgLabel : rawPieceIDs.drop_front(restIndex))
+        argLabels.push_back(MF.getIdentifier(rawArgLabel));
+
+      return DeclNameRef(ctx, moduleSelector, baseName, argLabels);
+    }
+
+    ASSERT(rawPieceIDs.size() == restIndex);
+    return DeclNameRef(ctx, moduleSelector, baseName);
+  }
+
   Expected<Decl *> getDeclCheckedImpl(
     llvm::function_ref<bool(DeclAttributes)> matchAttributes = nullptr);
 
@@ -3692,7 +3750,8 @@ class DeclDeserializer {
       return declOrOffset;
 
     auto theStruct = MF.createDecl<StructDecl>(SourceLoc(), name, SourceLoc(),
-                                               std::nullopt, genericParams, DC);
+                                               ArrayRef<InheritedEntry>(),
+                                               genericParams, DC);
     declOrOffset = theStruct;
 
     // Read the generic environment.
@@ -3835,14 +3894,15 @@ class DeclDeserializer {
     ctor->setParameters(bodyParams);
 
     SmallVector<LifetimeDependenceInfo, 1> lifetimeDependencies;
-    while (auto info = MF.maybeReadLifetimeDependence(bodyParams->size() + 1)) {
+    while (auto info = MF.maybeReadLifetimeDependence()) {
       assert(info.has_value());
       lifetimeDependencies.push_back(*info);
     }
 
     ctx.evaluator.cacheOutput(LifetimeDependenceInfoRequest{ctor},
-                              lifetimeDependencies.empty()? std::nullopt :
-                                  ctx.AllocateCopy(lifetimeDependencies));
+                              lifetimeDependencies.empty()
+                                  ? ArrayRef<LifetimeDependenceInfo>()
+                                  : ctx.AllocateCopy(lifetimeDependencies));
 
     if (auto errorConvention = MF.maybeReadForeignErrorConvention())
       ctor->setForeignErrorConvention(*errorConvention);
@@ -4106,6 +4166,8 @@ class DeclDeserializer {
     bool isIsolated;
     bool isCompileTimeLiteral, isConstValue;
     bool isSending;
+    bool isCallerIsolated;
+    bool isAddressable;
     uint8_t rawDefaultArg;
     TypeID defaultExprType;
     uint8_t rawDefaultArgIsolation;
@@ -4118,6 +4180,8 @@ class DeclDeserializer {
                                          isCompileTimeLiteral,
                                          isConstValue,
                                          isSending,
+                                         isCallerIsolated,
+                                         isAddressable,
                                          rawDefaultArg,
                                          defaultExprType,
                                          rawDefaultArgIsolation,
@@ -4163,6 +4227,8 @@ class DeclDeserializer {
     param->setCompileTimeLiteral(isCompileTimeLiteral);
     param->setConstValue(isConstValue);
     param->setSending(isSending);
+    param->setCallerIsolated(isCallerIsolated);
+    param->setAddressable(isAddressable);
 
     // Decode the default argument kind.
     // FIXME: Default argument expression, if available.
@@ -4434,17 +4500,16 @@ class DeclDeserializer {
     ParameterList *paramList;
     SET_OR_RETURN_ERROR(paramList, MF.readParameterList());
     fn->setParameters(paramList);
-    auto numParams =
-        fn->hasImplicitSelfDecl() ? paramList->size() + 1 : paramList->size();
 
     SmallVector<LifetimeDependenceInfo, 1> lifetimeDependencies;
-    while (auto info = MF.maybeReadLifetimeDependence(numParams)) {
+    while (auto info = MF.maybeReadLifetimeDependence()) {
       assert(info.has_value());
       lifetimeDependencies.push_back(*info);
     }
 
     ctx.evaluator.cacheOutput(LifetimeDependenceInfoRequest{fn},
-                              lifetimeDependencies.empty() ? std::nullopt
+                              lifetimeDependencies.empty()
+                                  ? ArrayRef<LifetimeDependenceInfo>()
                                   : ctx.AllocateCopy(lifetimeDependencies));
 
     if (auto errorConvention = MF.maybeReadForeignErrorConvention())
@@ -4497,13 +4562,17 @@ class DeclDeserializer {
     return deserializeAnyFunc(scratch, blobData, /*isAccessor*/true);
   }
 
-  void deserializeConditionalSubstitutionConditions(
-      SmallVectorImpl<OpaqueTypeDecl::AvailabilityCondition> &conditions) {
+  void deserializeConditionalSubstitutionAvailabilityQueries(
+      SmallVectorImpl<AvailabilityQuery> &queries) {
     using namespace decls_block;
 
     SmallVector<uint64_t, 4> scratch;
     StringRef blobData;
 
+    // FIXME: [availability] Support arbitrary domains (rdar://156513787).
+    auto domain = ctx.getTargetAvailabilityDomain();
+    ASSERT(domain.isPlatform());
+
     while (true) {
       llvm::BitstreamEntry entry =
           MF.fatalIfUnexpected(MF.DeclTypeCursor.advance(AF_DontPopBlockAtEnd));
@@ -4518,16 +4587,17 @@ class DeclDeserializer {
         break;
 
       bool isUnavailability;
-      DEF_VER_TUPLE_PIECES(condition);
+      DEF_VER_TUPLE_PIECES(version);
 
       ConditionalSubstitutionConditionLayout::readRecord(
-          scratch, isUnavailability, LIST_VER_TUPLE_PIECES(condition));
+          scratch, isUnavailability, LIST_VER_TUPLE_PIECES(version));
 
-      llvm::VersionTuple condition;
-      DECODE_VER_TUPLE(condition);
+      llvm::VersionTuple version;
+      DECODE_VER_TUPLE(version);
 
-      conditions.push_back(std::make_pair(VersionRange::allGTE(condition),
-                                          isUnavailability));
+      queries.push_back(AvailabilityQuery::dynamic(
+                            domain, AvailabilityRange(version), std::nullopt)
+                            .asUnavailable(isUnavailability));
     }
   }
 
@@ -4554,10 +4624,10 @@ class DeclDeserializer {
       decls_block::ConditionalSubstitutionLayout::readRecord(
           scratch, substitutionMapRef);
 
-      SmallVector<OpaqueTypeDecl::AvailabilityCondition, 2> conditions;
-      deserializeConditionalSubstitutionConditions(conditions);
+      SmallVector<AvailabilityQuery, 2> queries;
+      deserializeConditionalSubstitutionAvailabilityQueries(queries);
 
-      if (conditions.empty())
+      if (queries.empty())
         return MF.diagnoseAndConsumeFatal();
 
       auto subMapOrError = MF.getSubstitutionMapChecked(substitutionMapRef);
@@ -4566,7 +4636,7 @@ class DeclDeserializer {
 
       limitedAvailability.push_back(
           OpaqueTypeDecl::ConditionallyAvailableSubstitutions::get(
-              ctx, conditions, subMapOrError.get()));
+              ctx, queries, subMapOrError.get()));
     }
   }
 
@@ -4664,7 +4734,9 @@ class DeclDeserializer {
         } else {
           limitedAvailability.push_back(
               OpaqueTypeDecl::ConditionallyAvailableSubstitutions::get(
-                  ctx, {{VersionRange::all(), /*unavailability=*/false}},
+                  ctx,
+                  {AvailabilityQuery::universallyConstant(
+                      /*value=*/true)},
                   subMapOrError.get()));
 
           opaqueDecl->setConditionallyAvailableSubstitutions(limitedAvailability);
@@ -4775,7 +4847,7 @@ class DeclDeserializer {
 
     auto proto = MF.createDecl<ProtocolDecl>(
         DC, SourceLoc(), SourceLoc(), name,
-        ArrayRef<PrimaryAssociatedTypeName>(), std::nullopt,
+        ArrayRef<PrimaryAssociatedTypeName>(), ArrayRef<InheritedEntry>(),
         /*TrailingWhere=*/nullptr);
     declOrOffset = proto;
 
@@ -5001,9 +5073,9 @@ class DeclDeserializer {
     if (declOrOffset.isComplete())
       return declOrOffset;
 
-    auto theClass =
-        MF.createDecl<ClassDecl>(SourceLoc(), name, SourceLoc(), std::nullopt,
-                                 genericParams, DC, isExplicitActorDecl);
+    auto theClass = MF.createDecl<ClassDecl>(
+        SourceLoc(), name, SourceLoc(), ArrayRef<InheritedEntry>(),
+        genericParams, DC, isExplicitActorDecl);
     declOrOffset = theClass;
 
     theClass->setGenericSignature(MF.getGenericSignature(genericSigID));
@@ -5084,8 +5156,9 @@ class DeclDeserializer {
     if (declOrOffset.isComplete())
       return declOrOffset;
 
-    auto theEnum = MF.createDecl<EnumDecl>(SourceLoc(), name, SourceLoc(),
-                                           std::nullopt, genericParams, DC);
+    auto theEnum =
+        MF.createDecl<EnumDecl>(SourceLoc(), name, SourceLoc(),
+                                ArrayRef<InheritedEntry>(), genericParams, DC);
 
     declOrOffset = theEnum;
 
@@ -5201,6 +5274,17 @@ class DeclDeserializer {
     elem->setAccess(std::max(cast<EnumDecl>(DC)->getFormalAccess(),
                              AccessLevel::Internal));
 
+    SmallVector<LifetimeDependenceInfo, 1> lifetimeDependencies;
+    while (auto info = MF.maybeReadLifetimeDependence()) {
+      assert(info.has_value());
+      lifetimeDependencies.push_back(*info);
+    }
+
+    ctx.evaluator.cacheOutput(LifetimeDependenceInfoRequest{elem},
+                              lifetimeDependencies.empty()
+                                  ? ArrayRef<LifetimeDependenceInfo>()
+                                  : ctx.AllocateCopy(lifetimeDependencies));
+
     return elem;
   }
 
@@ -5408,8 +5492,7 @@ class DeclDeserializer {
     ctx.evaluator.cacheOutput(ExtendedTypeRequest{extension},
                               std::move(extendedType));
     auto nominal = dyn_cast_or_null<NominalTypeDecl>(MF.getDecl(extendedNominalID));
-    ctx.evaluator.cacheOutput(ExtendedNominalRequest{extension},
-                              std::move(nominal));
+    extension->setExtendedNominal(nominal);
 
     if (isImplicit)
       extension->setImplicit();
@@ -5578,10 +5661,6 @@ class DeclDeserializer {
         builtinKind = BuiltinMacroKind::IsolationMacro;
         break;
 
-      case 3:
-        builtinKind = BuiltinMacroKind::SwiftSettingsMacro;
-        break;
-
       default:
         break;
       }
@@ -5727,6 +5806,49 @@ ModuleFile::getDeclChecked(
   return declOrOffset;
 }
 
+static std::optional<AvailabilityDomainKind>
+decodeDomainKind(uint8_t kind) {
+  switch (kind) {
+    case static_cast<uint8_t>(AvailabilityDomainKind::Universal):
+      return AvailabilityDomainKind::Universal;
+    case static_cast<uint8_t>(AvailabilityDomainKind::SwiftLanguageMode):
+      return AvailabilityDomainKind::SwiftLanguageMode;
+    case static_cast<uint8_t>(AvailabilityDomainKind::SwiftRuntime):
+      return AvailabilityDomainKind::SwiftRuntime;
+    case static_cast<uint8_t>(AvailabilityDomainKind::PackageDescription):
+      return AvailabilityDomainKind::PackageDescription;
+    case static_cast<uint8_t>(AvailabilityDomainKind::Embedded):
+      return AvailabilityDomainKind::Embedded;
+    case static_cast<uint8_t>(AvailabilityDomainKind::Platform):
+      return AvailabilityDomainKind::Platform;
+    case static_cast<uint8_t>(AvailabilityDomainKind::Custom):
+      return AvailabilityDomainKind::Custom;
+    default:
+      return std::nullopt;
+  }
+}
+
+static std::optional<AvailabilityDomain>
+decodeAvailabilityDomain(AvailabilityDomainKind domainKind,
+                         PlatformKind platformKind, ValueDecl *decl) {
+  switch (domainKind) {
+  case AvailabilityDomainKind::Universal:
+    return AvailabilityDomain::forUniversal();
+  case AvailabilityDomainKind::SwiftLanguageMode:
+    return AvailabilityDomain::forSwiftLanguageMode();
+  case AvailabilityDomainKind::SwiftRuntime:
+    return AvailabilityDomain::forSwiftRuntime();
+  case AvailabilityDomainKind::PackageDescription:
+    return AvailabilityDomain::forPackageDescription();
+  case AvailabilityDomainKind::Embedded:
+    return AvailabilityDomain::forEmbedded();
+  case AvailabilityDomainKind::Platform:
+    return AvailabilityDomain::forPlatform(platformKind);
+  case AvailabilityDomainKind::Custom:
+    return AvailabilityDomain::forCustom(decl);
+  }
+}
+
 Expected<AvailableAttr *>
 DeclDeserializer::readAvailable_DECL_ATTR(SmallVectorImpl<uint64_t> &scratch,
                                           StringRef blobData) {
@@ -5734,28 +5856,32 @@ DeclDeserializer::readAvailable_DECL_ATTR(SmallVectorImpl<uint64_t> &scratch,
   bool isUnavailable;
   bool isDeprecated;
   bool isNoAsync;
-  bool isPackageDescriptionVersionSpecific;
   bool isSPI;
-  bool isForEmbedded;
+  uint8_t rawDomainKind;
+  unsigned rawPlatform;
+  DeclID domainDeclID;
   DEF_VER_TUPLE_PIECES(Introduced);
   DEF_VER_TUPLE_PIECES(Deprecated);
   DEF_VER_TUPLE_PIECES(Obsoleted);
-  unsigned rawPlatform, messageSize, renameSize;
+  unsigned messageSize, renameSize;
 
   // Decode the record, pulling the version tuple information.
   serialization::decls_block::AvailableDeclAttrLayout::readRecord(
-      scratch, isImplicit, isUnavailable, isDeprecated, isNoAsync,
-      isPackageDescriptionVersionSpecific, isSPI, isForEmbedded,
+      scratch, isImplicit, isUnavailable, isDeprecated, isNoAsync, isSPI,
+      rawDomainKind, rawPlatform, domainDeclID,
       LIST_VER_TUPLE_PIECES(Introduced), LIST_VER_TUPLE_PIECES(Deprecated),
-      LIST_VER_TUPLE_PIECES(Obsoleted), rawPlatform, messageSize,
-      renameSize);
+      LIST_VER_TUPLE_PIECES(Obsoleted), messageSize, renameSize);
+
+  auto maybeDomainKind = decodeDomainKind(rawDomainKind);
+  if (!maybeDomainKind)
+    return llvm::make_error<InvalidEnumValueError>(rawDomainKind, "AvailabilityDomainKind");
 
   auto maybePlatform = platformFromUnsigned(rawPlatform);
   if (!maybePlatform.has_value())
     return llvm::make_error<InvalidEnumValueError>(rawPlatform, "PlatformKind");
 
-  PlatformKind platform = maybePlatform.value();
-
+  AvailabilityDomainKind domainKind = *maybeDomainKind;
+  PlatformKind platform = *maybePlatform;
   StringRef message = blobData.substr(0, messageSize);
   blobData = blobData.substr(messageSize);
   StringRef rename = blobData.substr(0, renameSize);
@@ -5774,23 +5900,26 @@ DeclDeserializer::readAvailable_DECL_ATTR(SmallVectorImpl<uint64_t> &scratch,
   else
     kind = AvailableAttr::Kind::Default;
 
-  AvailabilityDomain domain;
-  if (platform != PlatformKind::none) {
-    domain = AvailabilityDomain::forPlatform(platform);
-  } else if (!Introduced.empty() || !Deprecated.empty() || !Obsoleted.empty()) {
-    domain = isPackageDescriptionVersionSpecific
-                 ? AvailabilityDomain::forPackageDescription()
-                 : AvailabilityDomain::forSwiftLanguage();
-  } else if (isForEmbedded) {
-    domain = AvailabilityDomain::forEmbedded();
-  } else {
-    domain = AvailabilityDomain::forUniversal();
+  ValueDecl *domainDecl = nullptr;
+  if (domainDeclID) {
+    Decl *decodedDomainDecl = nullptr;
+    SET_OR_RETURN_ERROR(decodedDomainDecl, MF.getDeclChecked(domainDeclID));
+
+    if (decodedDomainDecl) {
+      domainDecl = dyn_cast<ValueDecl>(decodedDomainDecl);
+      if (!domainDecl)
+        return llvm::make_error<InavalidAvailabilityDomainError>();
+    }
   }
 
+  auto domain = decodeAvailabilityDomain(domainKind, platform, domainDecl);
+  if (!domain)
+    return llvm::make_error<InavalidAvailabilityDomainError>();
+
   auto attr = new (ctx)
-      AvailableAttr(SourceLoc(), SourceRange(), domain, SourceLoc(), kind, message, rename,
-                    Introduced, SourceRange(), Deprecated, SourceRange(),
-                    Obsoleted, SourceRange(), isImplicit, isSPI);
+      AvailableAttr(SourceLoc(), SourceRange(), *domain, SourceLoc(), kind,
+                    message, rename, Introduced, SourceRange(), Deprecated,
+                    SourceRange(), Obsoleted, SourceRange(), isImplicit, isSPI);
   return attr;
 }
 
@@ -5881,14 +6010,6 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
       DeclAttribute *Attr = nullptr;
       bool skipAttr = false;
       switch (recordID) {
-      case decls_block::Execution_DECL_ATTR: {
-        unsigned behavior;
-        serialization::decls_block::ExecutionDeclAttrLayout::readRecord(
-            scratch, behavior);
-        Attr = new (ctx) ExecutionAttr(static_cast<ExecutionKind>(behavior),
-                                       /*Implicit=*/false);
-        break;
-      }
       case decls_block::ABI_DECL_ATTR: {
         bool isImplicit;
         DeclID abiDeclID;
@@ -5952,9 +6073,10 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
 
       case decls_block::CDecl_DECL_ATTR: {
         bool isImplicit;
+        bool isUnderscored;
         serialization::decls_block::CDeclDeclAttrLayout::readRecord(
-            scratch, isImplicit);
-        Attr = new (ctx) CDeclAttr(blobData, isImplicit);
+            scratch, isImplicit, isUnderscored);
+        Attr = new (ctx) CDeclAttr(blobData, isImplicit, isUnderscored);
         break;
       }
 
@@ -6100,61 +6222,38 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
       }
 
       case decls_block::Specialize_DECL_ATTR: {
+        unsigned isPublic;
         unsigned exported;
         SpecializeAttr::SpecializationKind specializationKind;
         unsigned specializationKindVal;
         GenericSignatureID specializedSigID;
 
-        ArrayRef<uint64_t> rawPieceIDs;
-        uint64_t numArgs;
+        ArrayRef<uint64_t> rawTrailingIDs;
         uint64_t numSPIGroups;
         uint64_t numAvailabilityAttrs;
-        uint64_t numTypeErasedParams;
         DeclID targetFunID;
 
         serialization::decls_block::SpecializeDeclAttrLayout::readRecord(
-            scratch, exported, specializationKindVal, specializedSigID,
-            targetFunID, numArgs, numSPIGroups, numAvailabilityAttrs,
-            numTypeErasedParams, rawPieceIDs);
+            scratch, isPublic, exported, specializationKindVal, specializedSigID,
+            targetFunID, numSPIGroups, numAvailabilityAttrs, rawTrailingIDs);
 
-        assert(rawPieceIDs.size() == numArgs + numSPIGroups + numTypeErasedParams ||
-               rawPieceIDs.size() == (numArgs - 1 + numSPIGroups + numTypeErasedParams));
         specializationKind = specializationKindVal
                                  ? SpecializeAttr::SpecializationKind::Partial
                                  : SpecializeAttr::SpecializationKind::Full;
-        // The 'target' parameter.
-        DeclNameRef replacedFunctionName;
-        if (numArgs) {
-          bool numArgumentLabels = (numArgs == 1) ? 0 : numArgs - 2;
-          auto baseName = MF.getDeclBaseName(rawPieceIDs[0]);
-          SmallVector<Identifier, 4> pieces;
-          if (numArgumentLabels) {
-            for (auto pieceID : rawPieceIDs.slice(1, numArgumentLabels))
-              pieces.push_back(MF.getIdentifier(pieceID));
-          }
-          replacedFunctionName = (numArgs == 1)
-                                     ? DeclNameRef({baseName}) // simple name
-                                     : DeclNameRef({ctx, baseName, pieces});
-        }
 
+        auto specializedSig = MF.getGenericSignature(specializedSigID);
+
+        // Take `numSPIGroups` trailing identifiers for the SPI groups.
         SmallVector<Identifier, 4> spis;
-        if (numSPIGroups) {
-          auto numTargetFunctionPiecesToSkip =
-              (rawPieceIDs.size() == numArgs + numSPIGroups + numTypeErasedParams) ? numArgs
-                                                             : numArgs - 1;
-          for (auto id : rawPieceIDs.slice(numTargetFunctionPiecesToSkip))
+          for (auto id : rawTrailingIDs.take_front(numSPIGroups))
             spis.push_back(MF.getIdentifier(id));
-        }
 
+        // Take the rest for type-erased parameters.
         SmallVector<Type, 4> typeErasedParams;
-        if (numTypeErasedParams) {
-          auto numTargetFunctionPiecesToSkip =
-              (rawPieceIDs.size() == numArgs + numSPIGroups + numTypeErasedParams) ? numArgs + numSPIGroups
-                                                             : numArgs - 1 + numSPIGroups;
-          for (auto id : rawPieceIDs.slice(numTargetFunctionPiecesToSkip))
-            typeErasedParams.push_back(MF.getType(id));
-        }
+        for (auto id : rawTrailingIDs.drop_front(numSPIGroups))
+          typeErasedParams.push_back(MF.getType(id));
 
+        // Read availability attrs.
         SmallVector<AvailableAttr *, 4> availabilityAttrs;
         while (numAvailabilityAttrs) {
           // Prepare to read the next record.
@@ -6184,10 +6283,17 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
           --numAvailabilityAttrs;
         }
 
-        auto specializedSig = MF.getGenericSignature(specializedSigID);
-        Attr = SpecializeAttr::create(ctx, exported != 0, specializationKind,
+        // Read target function DeclNameRef, if present.
+        DeclNameRef targetFunName = deserializeDeclNameRefIfPresent();
+        if (isPublic)
+          Attr = SpecializedAttr::create(ctx, exported != 0, specializationKind,
                                       spis, availabilityAttrs, typeErasedParams,
-                                      specializedSig, replacedFunctionName, &MF,
+                                      specializedSig, targetFunName, &MF,
+                                      targetFunID);
+        else
+          Attr = SpecializeAttr::create(ctx, exported != 0, specializationKind,
+                                      spis, availabilityAttrs, typeErasedParams,
+                                      specializedSig, targetFunName, &MF,
                                       targetFunID);
         break;
       }
@@ -6218,21 +6324,15 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
 
       case decls_block::DynamicReplacement_DECL_ATTR: {
         bool isImplicit;
-        uint64_t numArgs;
-        ArrayRef<uint64_t> rawPieceIDs;
         DeclID replacedFunID;
         serialization::decls_block::DynamicReplacementDeclAttrLayout::
-            readRecord(scratch, isImplicit, replacedFunID, numArgs, rawPieceIDs);
+            readRecord(scratch, isImplicit, replacedFunID);
 
-        auto baseName = MF.getDeclBaseName(rawPieceIDs[0]);
-        SmallVector<Identifier, 4> pieces;
-        for (auto pieceID : rawPieceIDs.slice(1))
-          pieces.push_back(MF.getIdentifier(pieceID));
+        DeclNameRef replacedFunName = deserializeDeclNameRefIfPresent();
 
-        assert(numArgs != 0);
         assert(!isImplicit && "Need to update for implicit");
-        Attr = DynamicReplacementAttr::create(
-            ctx, DeclNameRef({ ctx, baseName, pieces }), &MF, replacedFunID);
+        Attr = DynamicReplacementAttr::create(ctx, replacedFunName, &MF,
+                                              replacedFunID);
         break;
       }
 
@@ -6303,7 +6403,6 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
 
       case decls_block::Derivative_DECL_ATTR: {
         bool isImplicit;
-        uint64_t origNameId;
         bool hasAccessorKind;
         uint64_t rawAccessorKind;
         DeclID origDeclId;
@@ -6311,7 +6410,7 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
         ArrayRef<uint64_t> parameters;
 
         serialization::decls_block::DerivativeDeclAttrLayout::readRecord(
-            scratch, isImplicit, origNameId, hasAccessorKind, rawAccessorKind,
+            scratch, isImplicit, hasAccessorKind, rawAccessorKind,
             origDeclId, rawDerivativeKind, parameters);
 
         std::optional<AccessorKind> accessorKind = std::nullopt;
@@ -6322,8 +6421,6 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
           accessorKind = *maybeAccessorKind;
         }
 
-        DeclNameRefWithLoc origName{DeclNameRef(MF.getDeclBaseName(origNameId)),
-                                    DeclNameLoc(), accessorKind};
         auto derivativeKind =
             getActualAutoDiffDerivativeFunctionKind(rawDerivativeKind);
         if (!derivativeKind)
@@ -6333,9 +6430,14 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
           parametersBitVector[i] = parameters[i];
         auto *indices = IndexSubset::get(ctx, parametersBitVector);
 
+        auto origName = deserializeDeclNameRefIfPresent();
+        DeclNameRefWithLoc origNameWithLoc{origName, DeclNameLoc(),
+                                           accessorKind};
+
         auto *derivativeAttr =
             DerivativeAttr::create(ctx, isImplicit, SourceLoc(), SourceRange(),
-                                   /*baseType*/ nullptr, origName, indices);
+                                   /*baseType*/ nullptr, origNameWithLoc,
+                                   indices);
         derivativeAttr->setOriginalFunctionResolver(&MF, origDeclId);
         derivativeAttr->setDerivativeKind(*derivativeKind);
         Attr = derivativeAttr;
@@ -6344,20 +6446,21 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
 
       case decls_block::Transpose_DECL_ATTR: {
         bool isImplicit;
-        uint64_t origNameId;
         DeclID origDeclId;
         ArrayRef<uint64_t> parameters;
 
         serialization::decls_block::TransposeDeclAttrLayout::readRecord(
-            scratch, isImplicit, origNameId, origDeclId, parameters);
+            scratch, isImplicit, origDeclId, parameters);
 
-        DeclNameRefWithLoc origName{DeclNameRef(MF.getDeclBaseName(origNameId)),
-                                    DeclNameLoc(), std::nullopt};
         auto *origDecl = cast<AbstractFunctionDecl>(MF.getDecl(origDeclId));
         llvm::SmallBitVector parametersBitVector(parameters.size());
         for (unsigned i : indices(parameters))
           parametersBitVector[i] = parameters[i];
         auto *indices = IndexSubset::get(ctx, parametersBitVector);
+
+        auto origNameRef = deserializeDeclNameRefIfPresent();
+        DeclNameRefWithLoc origName{origNameRef, DeclNameLoc(), std::nullopt};
+
         auto *transposeAttr =
             TransposeAttr::create(ctx, isImplicit, SourceLoc(), SourceRange(),
                                   /*baseTypeRepr*/ nullptr, origName, indices);
@@ -6472,11 +6575,23 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
       }
 
       case decls_block::Nonisolated_DECL_ATTR: {
-        bool isUnsafe{};
+        unsigned modifier;
         bool isImplicit{};
         serialization::decls_block::NonisolatedDeclAttrLayout::readRecord(
-            scratch, isUnsafe, isImplicit);
-        Attr = new (ctx) NonisolatedAttr(isUnsafe, isImplicit);
+            scratch, modifier, isImplicit);
+        Attr = new (ctx) NonisolatedAttr(
+            {}, {}, static_cast<NonIsolatedModifier>(modifier), isImplicit);
+        break;
+      }
+
+      case decls_block::InheritActorContext_DECL_ATTR: {
+        unsigned modifier;
+        bool isImplicit{};
+        serialization::decls_block::InheritActorContextDeclAttrLayout::
+            readRecord(scratch, modifier, isImplicit);
+        Attr = new (ctx) InheritActorContextAttr(
+            {}, {}, static_cast<InheritActorContextModifier>(modifier),
+            isImplicit);
         break;
       }
 
@@ -6587,6 +6702,14 @@ llvm::Error DeclDeserializer::deserializeDeclCommon() {
         break;
       }
 
+      case decls_block::Nonexhaustive_DECL_ATTR: {
+        unsigned mode;
+        serialization::decls_block::NonexhaustiveDeclAttrLayout::readRecord(
+            scratch, mode);
+        Attr = new (ctx) NonexhaustiveAttr((NonexhaustiveMode)mode);
+        break;
+      }
+
 #define SIMPLE_DECL_ATTR(NAME, CLASS, ...) \
       case decls_block::CLASS##_DECL_ATTR: { \
         bool isImplicit; \
@@ -6958,6 +7081,8 @@ getActualResultConvention(uint8_t raw) {
   CASE(UnownedInnerPointer)
   CASE(Autoreleased)
   CASE(Pack)
+  CASE(GuaranteedAddress)
+  CASE(Guaranteed)
 #undef CASE
   }
   return std::nullopt;
@@ -7281,7 +7406,7 @@ detail::function_deserializer::deserialize(ModuleFile &MF,
   auto isolation = swift::FunctionTypeIsolation::forNonIsolated();
   if (rawIsolation == unsigned(FunctionTypeIsolation::NonIsolated)) {
     // do nothing
-  } else if (rawIsolation == unsigned(FunctionTypeIsolation::NonIsolatedCaller)) {
+  } else if (rawIsolation == unsigned(FunctionTypeIsolation::NonIsolatedNonsending)) {
     isolation = swift::FunctionTypeIsolation::forNonIsolatedCaller();
   } else if (rawIsolation == unsigned(FunctionTypeIsolation::Parameter)) {
     isolation = swift::FunctionTypeIsolation::forParameter();
@@ -7300,7 +7425,7 @@ detail::function_deserializer::deserialize(ModuleFile &MF,
   auto info = FunctionType::ExtInfoBuilder(
                   *representation, noescape, throws, thrownError, *diffKind,
                   clangFunctionType, isolation,
-                  /*LifetimeDependenceInfo */ std::nullopt, hasSendingResult)
+                  /*LifetimeDependenceInfo */ {}, hasSendingResult)
                   .withSendable(sendable)
                   .withAsync(async)
                   .build();
@@ -7357,8 +7482,7 @@ detail::function_deserializer::deserialize(ModuleFile &MF,
 
   SmallVector<LifetimeDependenceInfo, 1> lifetimeDependencies;
 
-  while (auto lifetimeDependence =
-             MF.maybeReadLifetimeDependence(params.size())) {
+  while (auto lifetimeDependence = MF.maybeReadLifetimeDependence()) {
     lifetimeDependencies.push_back(*lifetimeDependence);
   }
   if (!lifetimeDependencies.empty()) {
@@ -7580,12 +7704,13 @@ DESERIALIZE_TYPE(GENERIC_TYPE_PARAM_TYPE)(
   unsigned rawParamKind;
   bool hasDecl;
   unsigned depth;
+  unsigned weight;
   unsigned index;
   DeclID declOrIdentifier;
   TypeID valueTypeID;
 
   decls_block::GenericTypeParamTypeLayout::readRecord(
-      scratch, rawParamKind, hasDecl, depth, index, declOrIdentifier,
+      scratch, rawParamKind, hasDecl, depth, weight, index, declOrIdentifier,
       valueTypeID);
 
   auto paramKind = getActualParamKind(rawParamKind);
@@ -7614,10 +7739,11 @@ DESERIALIZE_TYPE(GENERIC_TYPE_PARAM_TYPE)(
     return valueType.takeError();
 
   if (declOrIdentifier == 0) {
-    return GenericTypeParamType::get(*paramKind, depth, index, *valueType,
+    return GenericTypeParamType::get(*paramKind, depth, index, weight, *valueType,
                                      MF.getContext());
   }
 
+  ASSERT(weight == 0);
   auto name = MF.getDeclBaseName(declOrIdentifier).getIdentifier();
   return GenericTypeParamType::get(name, *paramKind, depth, index, *valueType,
                                    MF.getContext());
@@ -7867,7 +7993,7 @@ Expected<Type> DESERIALIZE_TYPE(SIL_FUNCTION_TYPE)(
   auto extInfo = SILFunctionType::ExtInfoBuilder(
                      *representation, pseudogeneric, noescape, sendable, async,
                      unimplementable, isolation, *diffKind, clangFunctionType,
-                     /*LifetimeDependenceInfo*/ std::nullopt)
+                     /*LifetimeDependenceInfo*/ {})
                      .build();
 
   // Process the coroutine kind.
@@ -8008,7 +8134,7 @@ Expected<Type> DESERIALIZE_TYPE(SIL_FUNCTION_TYPE)(
 
   SmallVector<LifetimeDependenceInfo, 1> lifetimeDependencies;
 
-  while (auto lifetimeDependence = MF.maybeReadLifetimeDependence(numParams)) {
+  while (auto lifetimeDependence = MF.maybeReadLifetimeDependence()) {
     lifetimeDependencies.push_back(*lifetimeDependence);
   }
 
@@ -8370,7 +8496,8 @@ class SwiftToClangBasicReader :
     bool isRegularKeywordAttribute = readBool();
 
     clang::AttributeCommonInfo info(
-        name, scopeName, {rangeStart, rangeEnd}, scopeLoc, parsedKind,
+        name, clang::AttributeScopeInfo(scopeName, scopeLoc),
+        {rangeStart, rangeEnd}, parsedKind,
         {syntax, spellingListIndex, /*IsAlignas=*/false,
          isRegularKeywordAttribute});
 
@@ -8399,15 +8526,15 @@ class SwiftToClangBasicReader :
   clang::TypeCoupledDeclRefInfo readTypeCoupledDeclRefInfo() {
     llvm_unreachable("TypeCoupledDeclRefInfo shouldn't be reached from swift");
   }
+  clang::SpirvOperand readHLSLSpirvOperand() {
+    llvm_unreachable("SpirvOperand shouldn't be reached from swift");
+  }
 };
 
 } // end anonymous namespace
 
 llvm::Expected<const clang::Type *>
 ModuleFile::getClangType(ClangTypeID TID) {
-  if (!getContext().LangOpts.UseClangFunctionTypes)
-    return nullptr;
-
   if (TID == 0)
     return nullptr;
 
@@ -8654,7 +8781,7 @@ class LazyConformanceLoaderInfo final
 
   LazyConformanceLoaderInfo(ArrayRef<uint64_t> ids)
     : NumConformances(ids.size()) {
-    auto buffer = getTrailingObjects<ProtocolConformanceID>();
+    auto *buffer = getTrailingObjects();
     for (unsigned i = 0, e = ids.size(); i != e; ++i)
       buffer[i] = ProtocolConformanceID(ids[i]);
   }
@@ -8672,8 +8799,7 @@ class LazyConformanceLoaderInfo final
 
   ArrayRef<ProtocolConformanceID> claim() {
     // TODO: free the memory here (if it's not used in multiple places?)
-    return llvm::ArrayRef(getTrailingObjects<ProtocolConformanceID>(),
-                          NumConformances);
+    return getTrailingObjects(NumConformances);
   }
 };
 } // end anonymous namespace
@@ -8740,8 +8866,9 @@ ModuleFile::loadReferencedFunctionDecl(const DerivativeAttr *DA,
   return cast<AbstractFunctionDecl>(getDecl(contextData));
 }
 
-ValueDecl *ModuleFile::loadTargetFunctionDecl(const SpecializeAttr *attr,
-                                              uint64_t contextData) {
+ValueDecl *ModuleFile::loadTargetFunctionDecl(
+  const AbstractSpecializeAttr *attr,
+  uint64_t contextData) {
   if (contextData == 0)
     return nullptr;
   return cast<AbstractFunctionDecl>(getDecl(contextData));
@@ -8800,10 +8927,14 @@ void ModuleFile::finishNormalConformance(NormalProtocolConformance *conformance,
     if (maybeConformance) {
       reqConformances.push_back(maybeConformance.get());
     } else if (getContext().LangOpts.EnableDeserializationRecovery) {
-      llvm::Error error = maybeConformance.takeError();
-      if (error.isA<ConformanceXRefError>() &&
-          !enableExtendedDeserializationRecovery()) {
+      // If a conformance is missing, mark the whole protocol conformance
+      // as invalid. Something is broken with the context.
+      conformance->setInvalid();
 
+      llvm::Error error = maybeConformance.takeError();
+      if (error.isA<ConformanceXRefError>()) {
+        // The error was printed along with creating the ConformanceXRefError.
+        // Print the note here explaining the side effect.
         std::string typeStr = conformance->getType()->getString();
         auto &diags = getContext().Diags;
         diags.diagnose(getSourceLoc(),
@@ -8811,12 +8942,12 @@ void ModuleFile::finishNormalConformance(NormalProtocolConformance *conformance,
                        typeStr, proto->getName());
 
         consumeError(std::move(error));
-        conformance->setInvalid();
         return;
       }
 
+      // Leave it up to the centralized service to report other errors.
       diagnoseAndConsumeError(std::move(error));
-      reqConformances.push_back(ProtocolConformanceRef::forInvalid());
+      return;
     } else {
       fatal(maybeConformance.takeError());
     }
@@ -9294,7 +9425,7 @@ bool ModuleFile::maybeReadLifetimeDependenceRecord(
 }
 
 std::optional<LifetimeDependenceInfo>
-ModuleFile::maybeReadLifetimeDependence(unsigned numParams) {
+ModuleFile::maybeReadLifetimeDependence() {
   using namespace decls_block;
 
   SmallVector<uint64_t, 8> scratch;
@@ -9303,28 +9434,29 @@ ModuleFile::maybeReadLifetimeDependence(unsigned numParams) {
   }
 
   unsigned targetIndex;
+  unsigned paramIndicesLength;
   bool isImmortal;
   bool hasInheritLifetimeParamIndices;
   bool hasScopeLifetimeParamIndices;
   bool hasAddressableParamIndices;
   ArrayRef<uint64_t> lifetimeDependenceData;
   LifetimeDependenceLayout::readRecord(
-      scratch, targetIndex, isImmortal, hasInheritLifetimeParamIndices,
-      hasScopeLifetimeParamIndices, hasAddressableParamIndices,
-      lifetimeDependenceData);
+      scratch, targetIndex, paramIndicesLength, isImmortal,
+      hasInheritLifetimeParamIndices, hasScopeLifetimeParamIndices,
+      hasAddressableParamIndices, lifetimeDependenceData);
 
-  SmallBitVector inheritLifetimeParamIndices(numParams, false);
-  SmallBitVector scopeLifetimeParamIndices(numParams, false);
-  SmallBitVector addressableParamIndices(numParams, false);
+  SmallBitVector inheritLifetimeParamIndices(paramIndicesLength, false);
+  SmallBitVector scopeLifetimeParamIndices(paramIndicesLength, false);
+  SmallBitVector addressableParamIndices(paramIndicesLength, false);
 
   unsigned startIndex = 0;
   auto pushData = [&](SmallBitVector &bits) {
-    for (unsigned i = 0; i < numParams; i++) {
+    for (unsigned i = 0; i < paramIndicesLength; i++) {
       if (lifetimeDependenceData[startIndex + i]) {
         bits.set(i);
       }
     }
-    startIndex += numParams;
+    startIndex += paramIndicesLength;
   };
 
   if (hasInheritLifetimeParamIndices) {
diff --git a/lib/Serialization/DeserializationErrors.h b/lib/Serialization/DeserializationErrors.h
index 900fbbc2f0056..96874b86ed4de 100644
--- a/lib/Serialization/DeserializationErrors.h
+++ b/lib/Serialization/DeserializationErrors.h
@@ -707,6 +707,24 @@ class ConformanceXRefError : public llvm::ErrorInfo<ConformanceXRefError,
   }
 };
 
+class InavalidAvailabilityDomainError
+    : public llvm::ErrorInfo<InavalidAvailabilityDomainError> {
+  friend ErrorInfo;
+  static const char ID;
+  void anchor() override;
+
+public:
+  InavalidAvailabilityDomainError() {}
+
+  void log(raw_ostream &OS) const override {
+    OS << "Invalid availability domain";
+  }
+
+  std::error_code convertToErrorCode() const override {
+    return llvm::inconvertibleErrorCode();
+  }
+};
+
 class PrettyStackTraceModuleFile : public llvm::PrettyStackTraceEntry {
   const char *Action;
   const ModuleFile &MF;
diff --git a/lib/Serialization/DeserializeSIL.cpp b/lib/Serialization/DeserializeSIL.cpp
index 9b96b3d54814f..020dc84653d4d 100644
--- a/lib/Serialization/DeserializeSIL.cpp
+++ b/lib/Serialization/DeserializeSIL.cpp
@@ -494,11 +494,11 @@ SILDeserializer::readDebugScopes(SILFunction *F,
 
     if (isFuncParent)
       Scope = new (SILMod) SILDebugScope(
-          Loc.value(), Parent.get<SILFunction *>(), nullptr, InlinedCallSite);
+          Loc.value(), cast<SILFunction *>(Parent), nullptr, InlinedCallSite);
     else
       Scope = new (SILMod)
           SILDebugScope(Loc.value(), nullptr,
-                        Parent.get<const SILDebugScope *>(), InlinedCallSite);
+                        cast<const SILDebugScope *>(Parent), InlinedCallSite);
 
     ParsedScopes.insert({ParsedScopes.size() + 1, Scope});
 
@@ -734,8 +734,8 @@ llvm::Expected<SILFunction *> SILDeserializer::readSILFunctionChecked(
   GenericSignatureID genericSigID;
   unsigned rawLinkage, isTransparent, serializedKind, isThunk,
       isWithoutActuallyEscapingThunk, specialPurpose, inlineStrategy,
-      optimizationMode, perfConstr, subclassScope, hasCReferences, effect,
-      numAttrs, hasQualifiedOwnership, isWeakImported,
+      optimizationMode, perfConstr, subclassScope, hasCReferences,
+      markedAsUsed, effect, numAttrs, hasQualifiedOwnership, isWeakImported,
       LIST_VER_TUPLE_PIECES(available), isDynamic, isExactSelfClass,
       isDistributed, isRuntimeAccessible, forceEnableLexicalLifetimes,
       onlyReferencedByDebugInfo;
@@ -743,8 +743,8 @@ llvm::Expected<SILFunction *> SILDeserializer::readSILFunctionChecked(
   SILFunctionLayout::readRecord(
       scratch, rawLinkage, isTransparent, serializedKind, isThunk,
       isWithoutActuallyEscapingThunk, specialPurpose, inlineStrategy,
-      optimizationMode, perfConstr, subclassScope, hasCReferences, effect,
-      numAttrs, hasQualifiedOwnership, isWeakImported,
+      optimizationMode, perfConstr, subclassScope, hasCReferences, markedAsUsed,
+      effect, numAttrs, hasQualifiedOwnership, isWeakImported,
       LIST_VER_TUPLE_PIECES(available), isDynamic, isExactSelfClass,
       isDistributed, isRuntimeAccessible, forceEnableLexicalLifetimes,
       onlyReferencedByDebugInfo, funcTyID, replacedFunctionID,
@@ -917,6 +917,7 @@ llvm::Expected<SILFunction *> SILDeserializer::readSILFunctionChecked(
     fn->setIsAlwaysWeakImported(isWeakImported);
     fn->setClassSubclassScope(SubclassScope(subclassScope));
     fn->setHasCReferences(bool(hasCReferences));
+    fn->setMarkedAsUsed(bool(markedAsUsed));
 
     llvm::VersionTuple available;
     DECODE_VER_TUPLE(available);
@@ -2165,8 +2166,10 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
 
     std::optional<ApplyIsolationCrossing> IsolationCrossing;
     if (bool(ApplyCallerIsolation) || bool(ApplyCalleeIsolation)) {
-      auto caller = ActorIsolation(ActorIsolation::Kind(ApplyCallerIsolation));
-      auto callee = ActorIsolation(ActorIsolation::Kind(ApplyCalleeIsolation));
+      auto caller = ActorIsolation(ActorIsolation::Kind(ApplyCallerIsolation),
+                                   /*forSIL*/ true);
+      auto callee = ActorIsolation(ActorIsolation::Kind(ApplyCalleeIsolation),
+                                   /*forSIL*/ true);
       IsolationCrossing = {caller, callee};
     }
 
@@ -2209,8 +2212,10 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
 
     std::optional<ApplyIsolationCrossing> IsolationCrossing;
     if (bool(ApplyCallerIsolation) || bool(ApplyCalleeIsolation)) {
-      auto caller = ActorIsolation(ActorIsolation::Kind(ApplyCallerIsolation));
-      auto callee = ActorIsolation(ActorIsolation::Kind(ApplyCalleeIsolation));
+      auto caller = ActorIsolation(ActorIsolation::Kind(ApplyCallerIsolation),
+                                   /*forSIL*/true);
+      auto callee = ActorIsolation(ActorIsolation::Kind(ApplyCalleeIsolation),
+                                   /*forSIL*/true);
       IsolationCrossing = {caller, callee};
     }
 
@@ -2452,6 +2457,15 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
                       getSILType(Ty2, (SILValueCategory)TyCategory2, Fn)));
     break;
   }
+  case SILInstructionKind::VectorBaseAddrInst: {
+    assert(RecordKind == SIL_ONE_TYPE_ONE_OPERAND);
+    ResultInst = Builder.createVectorBaseAddr(
+        Loc,
+        getLocalValue(
+            Builder.maybeGetFunction(), ValID,
+            getSILType(MF->getType(TyID2), (SILValueCategory)TyCategory2, Fn)));
+    break;
+  }
   case SILInstructionKind::IndexAddrInst: {
     auto Ty = MF->getType(TyID);
     auto Ty2 = MF->getType(TyID2);
@@ -2558,10 +2572,7 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
   }
   // Checked Conversion instructions.
   case SILInstructionKind::UnconditionalCheckedCastInst: {
-    auto isolatedConformances = (ListOfValues[4] & 0x01)
-        ? CastingIsolatedConformances::Prohibit
-        : CastingIsolatedConformances::Allow;
-
+    CheckedCastInstOptions options(ListOfValues[4]);
     SILType srcLoweredType = getSILType(MF->getType(ListOfValues[1]),
                                         (SILValueCategory)ListOfValues[2], Fn);
     SILValue src = getLocalValue(Builder.maybeGetFunction(), ListOfValues[0],
@@ -2572,7 +2583,7 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
     CanType targetFormalType =
         MF->getType(ListOfValues[3])->getCanonicalType();
     ResultInst = Builder.createUnconditionalCheckedCast(
-        Loc, isolatedConformances, src, targetLoweredType, targetFormalType);
+        Loc, options, src, targetLoweredType, targetFormalType);
     break;
   }
 
@@ -2726,6 +2737,15 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
     break;
   }
 
+  case SILInstructionKind::EndCOWMutationAddrInst: {
+    assert(RecordKind == SIL_ONE_OPERAND && "Layout should be OneOperand.");
+    ResultInst = Builder.createEndCOWMutationAddr(
+        Loc, getLocalValue(Builder.maybeGetFunction(), ValID,
+                           getSILType(MF->getType(TyID),
+                                      (SILValueCategory)TyCategory, Fn)));
+    break;
+  }
+
   case SILInstructionKind::DestructureTupleInst: {
     assert(RecordKind == SIL_ONE_OPERAND && "Layout should be OneOperand.");
     SILValue Operand = getLocalValue(
@@ -3004,7 +3024,6 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
         getLocalValue(Builder.maybeGetFunction(), ValID2, addrType), qualifier);
     break;
   }
-  case SILInstructionKind::AssignByWrapperInst:
   case SILInstructionKind::AssignOrInitInst:
     llvm_unreachable("not supported");
   case SILInstructionKind::BindMemoryInst: {
@@ -3536,9 +3555,7 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
     // Format: the cast kind, a typed value, a BasicBlock ID for success,
     // a BasicBlock ID for failure. Uses SILOneTypeValuesLayout.
     bool isExact = (ListOfValues[0] & 0x01) != 0;
-    auto isolatedConformances = (ListOfValues[0] & 0x02)
-        ? CastingIsolatedConformances::Prohibit
-        : CastingIsolatedConformances::Allow;
+    CheckedCastInstOptions options(ListOfValues[0] >> 1);
     CanType sourceFormalType = MF->getType(ListOfValues[1])->getCanonicalType();
     SILType opTy = getSILType(MF->getType(ListOfValues[3]),
                               (SILValueCategory)ListOfValues[4], Fn);
@@ -3551,7 +3568,7 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
     auto *failureBB = getBBForReference(Fn, ListOfValues[7]);
 
     ResultInst =
-        Builder.createCheckedCastBranch(Loc, isExact, isolatedConformances,
+        Builder.createCheckedCastBranch(Loc, isExact, options,
                                         op, sourceFormalType,
                                         targetLoweredType, targetFormalType,
                                         successBB, failureBB,
@@ -3560,10 +3577,7 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
   }
   case SILInstructionKind::UnconditionalCheckedCastAddrInst: {
     // ignore attr.
-    auto isolatedConformances = (ListOfValues[6] & 0x01)
-        ? CastingIsolatedConformances::Prohibit
-        : CastingIsolatedConformances::Allow;
-
+    CheckedCastInstOptions options(ListOfValues[6]);
     CanType srcFormalType = MF->getType(ListOfValues[0])->getCanonicalType();
     SILType srcLoweredType = getSILType(MF->getType(ListOfValues[2]),
                                        (SILValueCategory)ListOfValues[3], Fn);
@@ -3577,15 +3591,13 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
                                   targetLoweredType);
 
     ResultInst = Builder.createUnconditionalCheckedCastAddr(
-        Loc, isolatedConformances, src, srcFormalType, dest, targetFormalType);
+        Loc, options, src, srcFormalType, dest, targetFormalType);
     break;
   }
   case SILInstructionKind::CheckedCastAddrBranchInst: {
     unsigned flags = ListOfValues[0];
-    auto isolatedConformances = flags & 0x01
-      ? CastingIsolatedConformances::Prohibit
-      : CastingIsolatedConformances::Allow;
-    CastConsumptionKind consumption = getCastConsumptionKind(flags >> 1);
+    CheckedCastInstOptions options(flags & 0xFF);
+    CastConsumptionKind consumption = getCastConsumptionKind(flags >> 8);
 
     CanType srcFormalType = MF->getType(ListOfValues[1])->getCanonicalType();
     SILType srcLoweredType = getSILType(MF->getType(ListOfValues[3]),
@@ -3603,7 +3615,7 @@ bool SILDeserializer::readSILInstruction(SILFunction *Fn,
     auto *successBB = getBBForReference(Fn, ListOfValues[7]);
     auto *failureBB = getBBForReference(Fn, ListOfValues[8]);
     ResultInst = Builder.createCheckedCastAddrBranch(
-        Loc, isolatedConformances, consumption, src, srcFormalType, dest,
+        Loc, options, consumption, src, srcFormalType, dest,
         targetFormalType, successBB, failureBB);
     break;
   }
@@ -3955,8 +3967,8 @@ bool SILDeserializer::hasSILFunction(StringRef Name,
   GenericSignatureID genericSigID;
   unsigned rawLinkage, isTransparent, serializedKind, isThunk,
       isWithoutActuallyEscapingThunk, isGlobal, inlineStrategy,
-      optimizationMode, perfConstr, subclassScope, hasCReferences, effect,
-      numSpecAttrs, hasQualifiedOwnership, isWeakImported,
+      optimizationMode, perfConstr, subclassScope, hasCReferences, markedAsUsed,
+      effect, numSpecAttrs, hasQualifiedOwnership, isWeakImported,
       LIST_VER_TUPLE_PIECES(available), isDynamic, isExactSelfClass,
       isDistributed, isRuntimeAccessible, forceEnableLexicalLifetimes,
       onlyReferencedByDebugInfo;
@@ -3964,8 +3976,8 @@ bool SILDeserializer::hasSILFunction(StringRef Name,
   SILFunctionLayout::readRecord(
       scratch, rawLinkage, isTransparent, serializedKind, isThunk,
       isWithoutActuallyEscapingThunk, isGlobal, inlineStrategy,
-      optimizationMode, perfConstr, subclassScope, hasCReferences, effect,
-      numSpecAttrs, hasQualifiedOwnership, isWeakImported,
+      optimizationMode, perfConstr, subclassScope, hasCReferences, markedAsUsed,
+      effect, numSpecAttrs, hasQualifiedOwnership, isWeakImported,
       LIST_VER_TUPLE_PIECES(available), isDynamic, isExactSelfClass,
       isDistributed, isRuntimeAccessible, forceEnableLexicalLifetimes,
       onlyReferencedByDebugInfo, funcTyID, replacedFunctionID,
@@ -4066,9 +4078,11 @@ SILGlobalVariable *SILDeserializer::readGlobalVar(StringRef Name) {
 
   TypeID TyID;
   DeclID dID;
-  unsigned rawLinkage, serializedKind, IsDeclaration, IsLet;
+  ModuleID parentModuleID;
+  unsigned rawLinkage, serializedKind, IsDeclaration, IsLet, IsUsed;
   SILGlobalVarLayout::readRecord(scratch, rawLinkage, serializedKind,
-                                 IsDeclaration, IsLet, TyID, dID);
+                                 IsDeclaration, IsLet, IsUsed, TyID, dID,
+                                 parentModuleID);
   if (TyID == 0) {
     LLVM_DEBUG(llvm::dbgs() << "SILGlobalVariable typeID is 0.\n");
     return nullptr;
@@ -4099,9 +4113,13 @@ SILGlobalVariable *SILDeserializer::readGlobalVar(StringRef Name) {
       Name.str(), getSILType(Ty, SILValueCategory::Object, nullptr),
       std::nullopt, globalDecl);
   v->setLet(IsLet);
+  v->setMarkedAsUsed(IsUsed);
   globalVarOrOffset.set(v, true /*isFullyDeserialized*/);
   v->setDeclaration(IsDeclaration);
 
+  if (parentModuleID)
+    v->setParentModule(MF->getModule(parentModuleID));
+
   if (Callback)
     Callback->didDeserialize(MF->getAssociatedModule(), v);
 
@@ -4464,8 +4482,7 @@ void SILDeserializer::getAllProperties() {
 void SILDeserializer::readWitnessTableEntries(
     llvm::BitstreamEntry &entry,
     std::vector<SILWitnessTable::Entry> &witnessEntries,
-    std::vector<SILWitnessTable::ConditionalConformance>
-      &conditionalConformances) {
+    std::vector<ProtocolConformanceRef> &conditionalConformances) {
   SmallVector<uint64_t, 64> scratch;
   llvm::Expected<unsigned> maybeKind = SILCursor.readRecord(entry.ID, scratch);
   if (!maybeKind)
@@ -4489,15 +4506,12 @@ void SILDeserializer::readWitnessTableEntries(
       });
     } else if (kind == SIL_WITNESS_ASSOC_PROTOCOL) {
       TypeID origTypeId;
-      DeclID substTypeId;
       ProtocolConformanceID conformanceId;
-      WitnessAssocProtocolLayout::readRecord(scratch, origTypeId, substTypeId,
-                                             conformanceId);
+      WitnessAssocProtocolLayout::readRecord(scratch, origTypeId, conformanceId);
       CanType origType = MF->getType(origTypeId)->getCanonicalType();
-      CanType substType = MF->getType(substTypeId)->getCanonicalType();
       auto conformance = MF->getConformance(conformanceId);
       witnessEntries.push_back(SILWitnessTable::AssociatedConformanceWitness{
-        origType, substType, conformance
+        origType, conformance
       });
     } else if (kind == SIL_WITNESS_ASSOC_ENTRY) {
       DeclID assocId;
@@ -4525,14 +4539,11 @@ void SILDeserializer::readWitnessTableEntries(
       assert(kind == SIL_WITNESS_CONDITIONAL_CONFORMANCE &&
              "Content of WitnessTable should be in "
              "SIL_WITNESS_CONDITIONAL_CONFORMANCE.");
-      TypeID assocId;
       ProtocolConformanceID conformanceId;
-      WitnessConditionalConformanceLayout::readRecord(scratch, assocId,
+      WitnessConditionalConformanceLayout::readRecord(scratch,
                                                       conformanceId);
-      CanType type = MF->getType(assocId)->getCanonicalType();
       auto conformance = MF->getConformance(conformanceId);
-      conditionalConformances.push_back(
-          SILWitnessTable::ConditionalConformance{type, conformance});
+      conditionalConformances.push_back(conformance);
     }
 
     // Fetch the next record.
@@ -4598,9 +4609,10 @@ llvm::Expected<SILWitnessTable *>
 
   unsigned RawLinkage;
   unsigned IsDeclaration;
+  unsigned IsSpecialized;
   unsigned Serialized;
   ProtocolConformanceID conformance;
-  WitnessTableLayout::readRecord(scratch, RawLinkage, IsDeclaration,
+  WitnessTableLayout::readRecord(scratch, RawLinkage, IsDeclaration, IsSpecialized,
                                  Serialized, conformance);
   auto Linkage = fromStableSILLinkage(RawLinkage);
   if (!Linkage) {
@@ -4628,7 +4640,7 @@ llvm::Expected<SILWitnessTable *>
                                     theConformance);
 
   if (!existingWt)
-    existingWt = SILMod.lookUpWitnessTable(theConformance);
+    existingWt = SILMod.lookUpWitnessTable(theConformance, IsSpecialized != 0);
   auto wT = existingWt;
 
   // If we have an existing witness table, verify that the conformance matches
@@ -4643,7 +4655,7 @@ llvm::Expected<SILWitnessTable *>
 
   } else {
     // Otherwise, create a new witness table declaration.
-    wT = SILWitnessTable::create(SILMod, *Linkage, theConformance);
+    wT = SILWitnessTable::create(SILMod, *Linkage, theConformance, IsSpecialized != 0);
     if (Callback)
       Callback->didDeserialize(MF->getAssociatedModule(), wT);
   }
@@ -4676,7 +4688,7 @@ llvm::Expected<SILWitnessTable *>
     return nullptr;
 
   std::vector<SILWitnessTable::Entry> witnessEntries;
-  std::vector<SILWitnessTable::ConditionalConformance> conditionalConformances;
+  std::vector<ProtocolConformanceRef> conditionalConformances;
   readWitnessTableEntries(entry, witnessEntries, conditionalConformances);
 
   // If we've already serialized the module, don't mark the witness table
@@ -4821,7 +4833,7 @@ readDefaultWitnessTable(DeclID WId, SILDefaultWitnessTable *existingWt) {
     return nullptr;
 
   std::vector<SILWitnessTable::Entry> witnessEntries;
-  std::vector<SILWitnessTable::ConditionalConformance> conditionalConformances;
+  std::vector<ProtocolConformanceRef> conditionalConformances;
   readWitnessTableEntries(entry, witnessEntries, conditionalConformances);
 
   wT->convertToDefinition(witnessEntries);
diff --git a/lib/Serialization/DeserializeSIL.h b/lib/Serialization/DeserializeSIL.h
index 8fa5d79b92ab5..21edb3f60b548 100644
--- a/lib/Serialization/DeserializeSIL.h
+++ b/lib/Serialization/DeserializeSIL.h
@@ -179,8 +179,7 @@ namespace swift {
     void readWitnessTableEntries(
            llvm::BitstreamEntry &entry,
            std::vector<SILWitnessTable::Entry> &witnessEntries,
-           std::vector<SILWitnessTable::ConditionalConformance>
-             &conditionalConformances);
+           std::vector<ProtocolConformanceRef> &conditionalConformances);
     SILProperty *readProperty(serialization::DeclID);
     SILDefaultWitnessTable *
     readDefaultWitnessTable(serialization::DeclID,
diff --git a/lib/Serialization/ModuleFile.cpp b/lib/Serialization/ModuleFile.cpp
index be83e125db4ac..e23a263c59b55 100644
--- a/lib/Serialization/ModuleFile.cpp
+++ b/lib/Serialization/ModuleFile.cpp
@@ -165,15 +165,18 @@ ModuleFile::loadDependenciesForFileContext(const FileUnit *file,
     if (dependency.isHeader()) {
       // The path may be empty if the file being loaded is a partial AST,
       // and the current compiler invocation is a merge-modules step.
-      if (!dependency.Core.RawPath.empty() &&
-          !M->getASTContext().SearchPathOpts.BridgingHeaderChaining) {
+      if (!dependency.Core.RawPath.empty()) {
+        // If using bridging header chaining, just bind the entire bridging
+        // header pch to the module. Otherwise, import the header.
         bool hadError =
-            clangImporter->importHeader(dependency.Core.RawPath,
-                                        file->getParentModule(),
-                                        Core->importedHeaderInfo.fileSize,
-                                        Core->importedHeaderInfo.fileModTime,
-                                        Core->importedHeaderInfo.contents,
-                                        diagLoc);
+            M->getASTContext().SearchPathOpts.BridgingHeaderChaining
+                ? clangImporter->bindBridgingHeader(file->getParentModule(),
+                                                    diagLoc)
+                : clangImporter->importHeader(
+                      dependency.Core.RawPath, file->getParentModule(),
+                      Core->importedHeaderInfo.fileSize,
+                      Core->importedHeaderInfo.fileModTime,
+                      Core->importedHeaderInfo.contents, diagLoc);
         if (hadError)
           return error(Status::FailedToLoadBridgingHeader);
       }
@@ -423,9 +426,9 @@ ModuleFile::getModuleName(ASTContext &Ctx, StringRef modulePath,
   bool isFramework = false;
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       "", "", std::move(newBuf), nullptr, nullptr,
-      /*isFramework=*/isFramework, Ctx.SILOpts.EnableOSSAModules,
-      Ctx.LangOpts.SDKName, Ctx.SearchPathOpts.DeserializedPathRecoverer,
-      loadedModuleFile);
+      /*isFramework=*/isFramework,
+      Ctx.LangOpts.SDKName, Ctx.LangOpts.Target,
+      Ctx.SearchPathOpts.DeserializedPathRecoverer, loadedModuleFile);
   Name = loadedModuleFile->Name.str();
   return std::move(moduleBuf.get());
 }
@@ -1172,16 +1175,18 @@ void ModuleFile::collectBasicSourceFileInfo(
     auto fingerprintIncludingTypeMembers =
       Fingerprint::fromString(fpStrIncludingTypeMembers);
     if (!fingerprintIncludingTypeMembers) {
-      llvm::errs() << "Unconvertible fingerprint including type members'"
-                   << fpStrIncludingTypeMembers << "'\n";
-      abort();
+      ABORT([&](auto &out) {
+        out << "Unconvertible fingerprint including type members '"
+            << fpStrIncludingTypeMembers << "'";
+      });
     }
     auto fingerprintExcludingTypeMembers =
       Fingerprint::fromString(fpStrExcludingTypeMembers);
     if (!fingerprintExcludingTypeMembers) {
-      llvm::errs() << "Unconvertible fingerprint excluding type members'"
-                   << fpStrExcludingTypeMembers << "'\n";
-      abort();
+      ABORT([&](auto &out) {
+        out << "Unconvertible fingerprint excluding type members '"
+            << fpStrExcludingTypeMembers << "'";
+      });
     }
     callback(BasicSourceFileInfo(filePath,
                                  fingerprintIncludingTypeMembers.value(),
diff --git a/lib/Serialization/ModuleFile.h b/lib/Serialization/ModuleFile.h
index 3d46bdb0a6d71..28bb4da5104fd 100644
--- a/lib/Serialization/ModuleFile.h
+++ b/lib/Serialization/ModuleFile.h
@@ -142,24 +142,20 @@ class ModuleFile
   public:
     /*implicit*/ Serialized(serialization::BitOffset offset) : Value(offset) {}
 
-    bool isComplete() const {
-      return Value.template is<T>();
-    }
+    bool isComplete() const { return isa<T>(Value); }
 
-    T get() const {
-      return Value.template get<T>();
-    }
+    T get() const { return cast<T>(Value); }
 
     /*implicit*/ operator T() const {
       return get();
     }
 
     /*implicit*/ operator serialization::BitOffset() const {
-      return Value.template get<serialization::BitOffset>();
+      return cast<serialization::BitOffset>(Value);
     }
 
     /*implicit*/ operator RawBitOffset() const {
-      return Value.template get<serialization::BitOffset>();
+      return cast<serialization::BitOffset>(Value);
     }
 
     Serialized &operator=(T deserialized) {
@@ -714,10 +710,8 @@ class ModuleFile
   /// \c true if this module was built with strict memory safety.
   bool strictMemorySafety() const { return Core->strictMemorySafety(); }
 
-  /// \c true if this module was built with `ExtensibleEnums` feature enabled.
-  bool supportsExtensibleEnums() const {
-    return Core->supportsExtensibleEnums();
-  }
+  /// \c true if this module uses deferred code generation.
+  bool deferredCodeGen() const { return Core->deferredCodeGen(); }
 
   /// Associates this module file with the AST node representing it.
   ///
@@ -945,7 +939,7 @@ class ModuleFile
   loadDynamicallyReplacedFunctionDecl(const DynamicReplacementAttr *DRA,
                                       uint64_t contextData) override;
 
-  virtual ValueDecl *loadTargetFunctionDecl(const SpecializeAttr *attr,
+  virtual ValueDecl *loadTargetFunctionDecl(const AbstractSpecializeAttr *attr,
                                             uint64_t contextData) override;
   virtual AbstractFunctionDecl *
   loadReferencedFunctionDecl(const DerivativeAttr *DA,
@@ -1105,8 +1099,7 @@ class ModuleFile
   bool maybeReadLifetimeDependenceRecord(SmallVectorImpl<uint64_t> &scratch);
 
   // Reads lifetime dependence info from type if present.
-  std::optional<LifetimeDependenceInfo>
-  maybeReadLifetimeDependence(unsigned numParams);
+  std::optional<LifetimeDependenceInfo> maybeReadLifetimeDependence();
 
   // Reads lifetime dependence specifier from decl if present
   bool maybeReadLifetimeEntry(SmallVectorImpl<LifetimeEntry> &specifierList,
diff --git a/lib/Serialization/ModuleFileCoreTableInfo.h b/lib/Serialization/ModuleFileCoreTableInfo.h
index 2dc30c7e7d8cd..9a4d7fc9fab68 100644
--- a/lib/Serialization/ModuleFileCoreTableInfo.h
+++ b/lib/Serialization/ModuleFileCoreTableInfo.h
@@ -579,8 +579,10 @@ class ModuleFileSharedCore::DeclFingerprintsTableInfo {
                                Fingerprint::DIGEST_LENGTH};
     if (auto fp = Fingerprint::fromString(str))
       return fp.value();
-    llvm::errs() << "Unconvertable fingerprint '" << str << "'\n";
-    abort();
+
+    ABORT([&](auto &out) {
+      out << "Unconvertable fingerprint '" << str << "'";
+    });
   }
 };
 
diff --git a/lib/Serialization/ModuleFileSharedCore.cpp b/lib/Serialization/ModuleFileSharedCore.cpp
index e79aa78e20455..98dca3cfdf402 100644
--- a/lib/Serialization/ModuleFileSharedCore.cpp
+++ b/lib/Serialization/ModuleFileSharedCore.cpp
@@ -19,12 +19,14 @@
 #include "swift/AST/Module.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/LangOptions.h"
+#include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Parse/ParseVersion.h"
 #include "swift/Serialization/SerializedModuleLoader.h"
 #include "swift/Strings.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/OnDiskHashTable.h"
 #include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/TargetParser/Triple.h"
 
 using namespace swift;
 using namespace swift::serialization;
@@ -224,8 +226,8 @@ static bool readOptionsBlock(llvm::BitstreamCursor &cursor,
     case options_block::STRICT_MEMORY_SAFETY:
       extendedInfo.setStrictMemorySafety(true);
       break;
-    case options_block::EXTENSIBLE_ENUMS:
-      extendedInfo.setSupportsExtensibleEnums(true);
+    case options_block::DEFERRED_CODE_GEN:
+      extendedInfo.setDeferredCodeGen(true);
       break;
     default:
       // Unknown options record, possibly for use by a future version of the
@@ -240,9 +242,9 @@ static bool readOptionsBlock(llvm::BitstreamCursor &cursor,
 static ValidationInfo validateControlBlock(
     llvm::BitstreamCursor &cursor, SmallVectorImpl<uint64_t> &scratch,
     std::pair<uint16_t, uint16_t> expectedVersion,
-    bool requiresOSSAModules,
     bool requiresRevisionMatch,
     StringRef requiredSDK,
+    std::optional<llvm::Triple> target,
     ExtendedValidationInfo *extendedInfo,
     PathObfuscator &pathRecoverer) {
   // The control block is malformed until we've at least read a major version
@@ -378,9 +380,17 @@ static ValidationInfo validateControlBlock(
     case control_block::MODULE_NAME:
       result.name = blobData;
       break;
-    case control_block::TARGET:
+    case control_block::TARGET: {
       result.targetTriple = blobData;
+      if (target &&
+          !areCompatible(*target, llvm::Triple(llvm::Triple::normalize(
+                                      result.targetTriple)))) {
+        result.status = Status::TargetIncompatible;
+        return result;
+      }
+
       break;
+    }
     case control_block::ALLOWABLE_CLIENT_NAME:
       result.allowableClients.push_back(blobData);
       break;
@@ -394,7 +404,7 @@ static ValidationInfo validateControlBlock(
       // env var is set (for testing).
       static const char* forceDebugPreSDKRestriction =
         ::getenv("SWIFT_DEBUG_FORCE_SWIFTMODULE_PER_SDK");
-      if (!version::isCurrentCompilerTagged() &&
+      if (version::getCurrentCompilerSerializationTag().empty() &&
           !forceDebugPreSDKRestriction) {
         break;
       }
@@ -435,10 +445,12 @@ static ValidationInfo validateControlBlock(
         ::getenv("SWIFT_DEBUG_FORCE_SWIFTMODULE_REVISION");
 
       StringRef moduleRevision = blobData;
+      StringRef serializationTag =
+          version::getCurrentCompilerSerializationTag();
       if (forcedDebugRevision ||
-          (requiresRevisionMatch && version::isCurrentCompilerTagged())) {
-        StringRef compilerRevision = forcedDebugRevision ?
-          forcedDebugRevision : version::getCurrentCompilerSerializationTag();
+          (requiresRevisionMatch && !serializationTag.empty())) {
+        StringRef compilerRevision =
+            forcedDebugRevision ? forcedDebugRevision : serializationTag;
         if (moduleRevision != compilerRevision) {
           // The module versions are mismatching, record it and diagnose later.
           result.problematicRevision = moduleRevision;
@@ -471,12 +483,6 @@ static ValidationInfo validateControlBlock(
       }
       break;
     }
-    case control_block::IS_OSSA: {
-      auto isModuleInOSSA = scratch[0];
-      if (requiresOSSAModules && !isModuleInOSSA)
-        result.status = Status::NotInOSSA;
-      break;
-    }
     default:
       // Unknown metadata record, possibly for use by a future version of the
       // module format.
@@ -580,7 +586,6 @@ std::string serialization::StatusToString(Status S) {
   case Status::FormatTooNew: return "FormatTooNew";
   case Status::RevisionIncompatible: return "RevisionIncompatible";
   case Status::ChannelIncompatible: return "ChannelIncompatible";
-  case Status::NotInOSSA: return "NotInOSSA";
   case Status::MissingDependency: return "MissingDependency";
   case Status::MissingUnderlyingModule: return "MissingUnderlyingModule";
   case Status::CircularDependency: return "CircularDependency";
@@ -602,11 +607,12 @@ bool serialization::isSerializedAST(StringRef data) {
 }
 
 ValidationInfo serialization::validateSerializedAST(
-    StringRef data, bool requiresOSSAModules,
+    StringRef data,
     StringRef requiredSDK,
     ExtendedValidationInfo *extendedInfo,
     SmallVectorImpl<SerializationOptions::FileDependency> *dependencies,
-    SmallVectorImpl<SearchPath> *searchPaths) {
+    SmallVectorImpl<SearchPath> *searchPaths,
+    std::optional<llvm::Triple> target) {
   ValidationInfo result;
 
   // Check 32-bit alignment.
@@ -647,9 +653,8 @@ ValidationInfo serialization::validateSerializedAST(
       result = validateControlBlock(
           cursor, scratch,
           {SWIFTMODULE_VERSION_MAJOR, SWIFTMODULE_VERSION_MINOR},
-          requiresOSSAModules,
           /*requiresRevisionMatch=*/true,
-          requiredSDK,
+          requiredSDK, target,
           extendedInfo, localObfuscator);
       if (result.status != Status::Valid)
         return result;
@@ -697,23 +702,19 @@ std::string ModuleFileSharedCore::Dependency::getPrettyPrintedPath() const {
 }
 
 void ModuleFileSharedCore::fatal(llvm::Error error) const {
-  llvm::SmallString<0> errorStr;
-  llvm::raw_svector_ostream out(errorStr);
-
-  out << "*** DESERIALIZATION FAILURE ***\n";
-  out << "*** If any module named here was modified in the SDK, please delete the ***\n";
-  out << "*** new swiftmodule files from the SDK and keep only swiftinterfaces.   ***\n";
-  outputDiagnosticInfo(out);
-  out << "\n";
-  if (error) {
-    handleAllErrors(std::move(error), [&](const llvm::ErrorInfoBase &ei) {
-      ei.log(out);
-      out << "\n";
-    });
-  }
-
-  llvm::PrettyStackTraceString trace(errorStr.c_str());
-  abort();
+  ABORT([&](auto &out) {
+    out << "*** DESERIALIZATION FAILURE ***\n";
+    out << "*** If any module named here was modified in the SDK, please delete the ***\n";
+    out << "*** new swiftmodule files from the SDK and keep only swiftinterfaces.   ***\n";
+    outputDiagnosticInfo(out);
+    out << "\n";
+    if (error) {
+      handleAllErrors(std::move(error), [&](const llvm::ErrorInfoBase &ei) {
+        ei.log(out);
+        out << "\n";
+      });
+    }
+  });
 }
 
 void ModuleFileSharedCore::outputDiagnosticInfo(llvm::raw_ostream &os) const {
@@ -1203,9 +1204,9 @@ bool ModuleFileSharedCore::readModuleDocIfPresent(PathObfuscator &pathRecoverer)
 
       info = validateControlBlock(
           docCursor, scratch, {SWIFTDOC_VERSION_MAJOR, SWIFTDOC_VERSION_MINOR},
-          RequiresOSSAModules,
           /*requiresRevisionMatch*/false,
-          /*requiredSDK*/StringRef(), /*extendedInfo*/nullptr, pathRecoverer);
+          /*requiredSDK*/StringRef(), /*target*/std::nullopt,
+          /*extendedInfo*/nullptr, pathRecoverer);
       if (info.status != Status::Valid)
         return false;
       // Check that the swiftdoc is actually for this module.
@@ -1348,9 +1349,9 @@ bool ModuleFileSharedCore::readModuleSourceInfoIfPresent(PathObfuscator &pathRec
       info = validateControlBlock(
           infoCursor, scratch,
           {SWIFTSOURCEINFO_VERSION_MAJOR, SWIFTSOURCEINFO_VERSION_MINOR},
-          RequiresOSSAModules,
           /*requiresRevisionMatch*/false,
-          /*requiredSDK*/StringRef(), /*extendedInfo*/nullptr, pathRecoverer);
+          /*requiredSDK*/StringRef(), /*target*/std::nullopt,
+          /*extendedInfo*/nullptr, pathRecoverer);
       if (info.status != Status::Valid)
         return false;
       // Check that the swiftsourceinfo is actually for this module.
@@ -1413,11 +1414,13 @@ StringRef ModuleFileSharedCore::getIdentifierText(IdentifierID IID) const {
 
   assert(!IdentifierData.empty() && "no identifier data in module");
 
-  StringRef rawStrPtr = IdentifierData.substr(offset);
-  size_t terminatorOffset = rawStrPtr.find('\0');
-  assert(terminatorOffset != StringRef::npos &&
+  size_t endOffset = ((rawID + 1 < Identifiers.size()) ?
+    Identifiers[rawID + 1] : IdentifierData.size()) - 1;
+
+  ASSERT(IdentifierData[endOffset] == '\0' &&
          "unterminated identifier string data");
-  return rawStrPtr.slice(0, terminatorOffset);
+
+  return IdentifierData.slice(offset, endOffset);
 }
 
 ModuleFileSharedCore::ModuleFileSharedCore(
@@ -1425,13 +1428,12 @@ ModuleFileSharedCore::ModuleFileSharedCore(
     std::unique_ptr<llvm::MemoryBuffer> moduleDocInputBuffer,
     std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
     bool isFramework,
-    bool requiresOSSAModules,
     StringRef requiredSDK,
+    std::optional<llvm::Triple> target,
     serialization::ValidationInfo &info, PathObfuscator &pathRecoverer)
     : ModuleInputBuffer(std::move(moduleInputBuffer)),
       ModuleDocInputBuffer(std::move(moduleDocInputBuffer)),
-      ModuleSourceInfoInputBuffer(std::move(moduleSourceInfoInputBuffer)),
-      RequiresOSSAModules(requiresOSSAModules) {
+      ModuleSourceInfoInputBuffer(std::move(moduleSourceInfoInputBuffer)) {
   assert(!hasError());
   Bits.IsFramework = isFramework;
 
@@ -1478,8 +1480,7 @@ ModuleFileSharedCore::ModuleFileSharedCore(
       info = validateControlBlock(
           cursor, scratch,
           {SWIFTMODULE_VERSION_MAJOR, SWIFTMODULE_VERSION_MINOR},
-          RequiresOSSAModules,
-          /*requiresRevisionMatch=*/true, requiredSDK,
+          /*requiresRevisionMatch=*/true, requiredSDK, target,
           &extInfo, pathRecoverer);
       if (info.status != Status::Valid) {
         error(info.status);
@@ -1508,7 +1509,7 @@ ModuleFileSharedCore::ModuleFileSharedCore(
       Bits.AllowNonResilientAccess = extInfo.allowNonResilientAccess();
       Bits.SerializePackageEnabled = extInfo.serializePackageEnabled();
       Bits.StrictMemorySafety = extInfo.strictMemorySafety();
-      Bits.SupportsExtensibleEnums = extInfo.supportsExtensibleEnums();
+      Bits.DeferredCodeGen = extInfo.deferredCodeGen();
       MiscVersion = info.miscVersion;
       SDKVersion = info.sdkVersion;
       ModuleABIName = extInfo.getModuleABIName();
diff --git a/lib/Serialization/ModuleFileSharedCore.h b/lib/Serialization/ModuleFileSharedCore.h
index 278561f859e2d..ca0a132e82bb0 100644
--- a/lib/Serialization/ModuleFileSharedCore.h
+++ b/lib/Serialization/ModuleFileSharedCore.h
@@ -114,9 +114,6 @@ class ModuleFileSharedCore {
   /// \c true if this module has incremental dependency information.
   bool HasIncrementalInfo = false;
 
-  /// \c true if this module was compiled with -enable-ossa-modules.
-  bool RequiresOSSAModules;
-
   /// An array of module names that are allowed to import this one.
   ArrayRef<StringRef> AllowableClientNames;
 
@@ -421,8 +418,8 @@ class ModuleFileSharedCore {
     /// Whether this module enabled strict memory safety.
     unsigned StrictMemorySafety : 1;
 
-    /// Whether this module enabled has `ExtensibleEnums` feature enabled.
-    unsigned SupportsExtensibleEnums : 1;
+    /// Whether this module used deferred code generation.
+    unsigned DeferredCodeGen : 1;
 
     // Explicitly pad out to the next word boundary.
     unsigned : 1;
@@ -445,8 +442,8 @@ class ModuleFileSharedCore {
       std::unique_ptr<llvm::MemoryBuffer> moduleDocInputBuffer,
       std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
       bool isFramework,
-      bool requiresOSSAModules,
       StringRef requiredSDK,
+      std::optional<llvm::Triple> target,
       serialization::ValidationInfo &info, PathObfuscator &pathRecoverer);
 
   /// Change the status of the current module.
@@ -572,8 +569,10 @@ class ModuleFileSharedCore {
   /// of the buffer, even if there's an error in loading.
   /// \param isFramework If true, this is treated as a framework module for
   /// linking purposes.
-  /// \param requiresOSSAModules If true, this requires dependent modules to be
-  /// compiled with -enable-ossa-modules.
+  /// \param requiredSDK A string denoting the name of the currently-used SDK,
+  /// to ensure that the loaded module was built with a compatible SDK.
+  /// \param target The target triple of the current compilation for
+  /// validating that the module we are attempting to load is compatible.
   /// \param[out] theModule The loaded module.
   /// \returns Whether the module was successfully loaded, or what went wrong
   ///          if it was not.
@@ -582,14 +581,15 @@ class ModuleFileSharedCore {
        std::unique_ptr<llvm::MemoryBuffer> moduleInputBuffer,
        std::unique_ptr<llvm::MemoryBuffer> moduleDocInputBuffer,
        std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
-       bool isFramework, bool requiresOSSAModules,
-       StringRef requiredSDK, PathObfuscator &pathRecoverer,
+       bool isFramework,
+       StringRef requiredSDK, std::optional<llvm::Triple> target,
+       PathObfuscator &pathRecoverer,
        std::shared_ptr<const ModuleFileSharedCore> &theModule) {
     serialization::ValidationInfo info;
     auto *core = new ModuleFileSharedCore(
         std::move(moduleInputBuffer), std::move(moduleDocInputBuffer),
         std::move(moduleSourceInfoInputBuffer), isFramework,
-        requiresOSSAModules, requiredSDK, info,
+        requiredSDK, target, info,
         pathRecoverer);
     if (!moduleInterfacePath.empty()) {
       ArrayRef<char> path;
@@ -650,6 +650,11 @@ class ModuleFileSharedCore {
     return Bits.IsStaticLibrary;
   }
 
+  /// Was this module built with C++ interop enabled.
+  bool isBuiltWithCxxInterop() const {
+    return Bits.HasCxxInteroperability;
+  }
+
   llvm::VersionTuple getUserModuleVersion() const {
     return UserModuleVersion;
   }
@@ -659,10 +664,14 @@ class ModuleFileSharedCore {
     return MacroModuleNames;
   }
 
+  ArrayRef<serialization::SearchPath> getSearchPaths() const {
+    return SearchPaths;
+  }
+
   /// Get embedded bridging header.
-  std::string getEmbeddedHeader() const {
+  StringRef getEmbeddedHeader() const {
     // Don't include the '\0' in the end.
-    return importedHeaderInfo.contents.drop_back().str();
+    return importedHeaderInfo.contents.drop_back();
   }
 
   /// If the module-defining `.swiftinterface` file is an SDK-relative path,
@@ -684,7 +693,7 @@ class ModuleFileSharedCore {
 
   bool strictMemorySafety() const { return Bits.StrictMemorySafety; }
 
-  bool supportsExtensibleEnums() const { return Bits.SupportsExtensibleEnums; }
+  bool deferredCodeGen() const { return Bits.DeferredCodeGen; }
 
   /// How should \p dependency be loaded for a transitive import via \c this?
   ///
diff --git a/lib/Serialization/ModuleFormat.h b/lib/Serialization/ModuleFormat.h
index 5a15e14d29fd8..f650e43acaa07 100644
--- a/lib/Serialization/ModuleFormat.h
+++ b/lib/Serialization/ModuleFormat.h
@@ -58,7 +58,7 @@ const uint16_t SWIFTMODULE_VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t SWIFTMODULE_VERSION_MINOR = 933; // isConstantValue
+const uint16_t SWIFTMODULE_VERSION_MINOR = 965; // WriteImplKindField and ReadWriteImplKindField size
 
 /// A standard hash seed used for all string hashes in a serialized module.
 ///
@@ -208,7 +208,11 @@ enum class ReadImplKind : uint8_t {
   Address,
   Read,
   Read2,
+  Borrow,
+  LastReadImplKind = Borrow,
 };
+static_assert(countBitsUsed(static_cast<unsigned>(
+                  ReadImplKind::LastReadImplKind)) <= 3);
 using ReadImplKindField = BCFixed<3>;
 
 // These IDs must \em not be renumbered or reordered without incrementing
@@ -222,8 +226,12 @@ enum class WriteImplKind : uint8_t {
   MutableAddress,
   Modify,
   Modify2,
+  Mutate,
+  LastWriteImplKind = Mutate,
 };
-using WriteImplKindField = BCFixed<3>;
+static_assert(countBitsUsed(static_cast<unsigned>(
+                  WriteImplKind::LastWriteImplKind)) <= 4);
+using WriteImplKindField = BCFixed<4>;
 
 // These IDs must \em not be renumbered or reordered without incrementing
 // the module version.
@@ -236,8 +244,12 @@ enum class ReadWriteImplKind : uint8_t {
   Modify2,
   StoredWithDidSet,
   InheritedWithDidSet,
+  Mutate,
+  LastReadWriteImplKind = Mutate,
 };
-using ReadWriteImplKindField = BCFixed<3>;
+static_assert(countBitsUsed(static_cast<unsigned>(
+                  ReadWriteImplKind::LastReadWriteImplKind)) <= 4);
+using ReadWriteImplKindField = BCFixed<4>;
 
 // These IDs must \em not be renumbered or reordered without incrementing
 // the module version.
@@ -344,6 +356,8 @@ enum AccessorKind : uint8_t {
   Modify2,
   Init,
   DistributedGet,
+  Borrow,
+  Mutate,
 };
 using AccessorKindField = BCFixed<4>;
 
@@ -428,6 +442,8 @@ enum class ResultConvention : uint8_t {
   UnownedInnerPointer,
   Autoreleased,
   Pack,
+  GuaranteedAddress,
+  Guaranteed,
 };
 using ResultConventionField = BCFixed<3>;
 
@@ -707,8 +723,9 @@ enum class FunctionTypeIsolation : uint8_t {
   NonIsolated,
   Parameter,
   Erased,
+  NonIsolatedNonsending,
+  // NOTE: All of the new kinds should be added above.
   GlobalActorOffset, // Add this to the global actor type ID
-  NonIsolatedCaller,
 };
 using FunctionTypeIsolationField = TypeIDField;
 
@@ -759,6 +776,19 @@ using GenericParamKindField = BCFixed<2>;
       X##_HasSubminor = Y.getSubminor().has_value();\
     }
 
+// These IDs must \em not be renumbered or reordered without incrementing
+// the module version.
+enum class AvailabilityDomainKind : uint8_t {
+  Universal = 0,
+  SwiftLanguageMode,
+  PackageDescription,
+  Embedded,
+  Platform,
+  Custom,
+  SwiftRuntime,
+};
+using AvailabilityDomainKindField = BCFixed<3>;
+
 /// The various types of blocks that can occur within a serialized Swift
 /// module.
 ///
@@ -885,7 +915,6 @@ namespace control_block {
     TARGET,
     SDK_NAME,
     REVISION,
-    IS_OSSA,
     ALLOWABLE_CLIENT_NAME,
     CHANNEL,
     SDK_VERSION,
@@ -924,11 +953,6 @@ namespace control_block {
     BCBlob
   >;
 
-  using IsOSSALayout = BCRecordLayout<
-    IS_OSSA,
-    BCFixed<1>
-  >;
-
   using AllowableClientLayout = BCRecordLayout<
     ALLOWABLE_CLIENT_NAME,
     BCBlob
@@ -975,7 +999,7 @@ namespace options_block {
     PUBLIC_MODULE_NAME,
     SWIFT_INTERFACE_COMPILER_VERSION,
     STRICT_MEMORY_SAFETY,
-    EXTENSIBLE_ENUMS,
+    DEFERRED_CODE_GEN,
   };
 
   using SDKPathLayout = BCRecordLayout<
@@ -1076,6 +1100,10 @@ namespace options_block {
     STRICT_MEMORY_SAFETY
   >;
 
+  using DeferredCodeGenLayout = BCRecordLayout<
+    DEFERRED_CODE_GEN
+  >;
+
   using PublicModuleNameLayout = BCRecordLayout<
     PUBLIC_MODULE_NAME,
     BCBlob
@@ -1085,10 +1113,6 @@ namespace options_block {
     SWIFT_INTERFACE_COMPILER_VERSION,
     BCBlob // version tuple
   >;
-
-  using ExtensibleEnumsLayout = BCRecordLayout<
-    EXTENSIBLE_ENUMS
-  >;
 }
 
 /// The record types within the input block.
@@ -1233,6 +1257,8 @@ namespace decls_block {
 /// with a linker error.
 #define TYPE_LAYOUT(LAYOUT, ...) TYPE_LAYOUT_IMPL(LAYOUT, __VA_ARGS__)
 
+  // clang-format off
+
   using ClangTypeLayout = BCRecordLayout<
     CLANG_TYPE,
     BCArray<BCVBR<6>>
@@ -1249,6 +1275,15 @@ namespace decls_block {
     DeclIDField // API decl
   >;
 
+  /// A field containing the pieces of a \c DeclNameRef and the information
+  /// needed to reconstruct it.
+  using DeclNameRefLayout = BCRecordLayout<
+    DECL_NAME_REF,
+    BCFixed<1>, // isCompoundName
+    BCFixed<1>, // hasModuleSelector
+    BCArray<IdentifierIDField> // module selector, base name, arg labels
+  >;
+
   /// A placeholder for invalid types
   TYPE_LAYOUT(ErrorTypeLayout,
     ERROR_TYPE,
@@ -1281,7 +1316,8 @@ namespace decls_block {
     GenericParamKindField, // param kind
     BCFixed<1>,            // has decl?
     BCFixed<15>,           // depth
-    BCFixed<16>,           // index
+    BCFixed<1>,            // weight
+    BCFixed<15>,           // index
     DeclIDField,           // generic type parameter decl or identifier
     TypeIDField            // value type (if param kind == Value)
   );
@@ -1719,6 +1755,8 @@ namespace decls_block {
     BCFixed<1>,              // isCompileTimeLiteral?
     BCFixed<1>,              // isConst?
     BCFixed<1>,              // isSending?
+    BCFixed<1>,              // isCallerIsolated?
+    BCFixed<1>,              // isAddressable?
     DefaultArgumentField,    // default argument kind
     TypeIDField,             // default argument type
     ActorIsolationField,     // default argument isolation
@@ -2223,7 +2261,8 @@ namespace decls_block {
   using CDeclDeclAttrLayout = BCRecordLayout<
     CDecl_DECL_ATTR,
     BCFixed<1>, // implicit flag
-    BCBlob      // _silgen_name
+    BCFixed<1>, // underscored flag
+    BCBlob      // cname
   >;
 
   using ImplementsDeclAttrLayout = BCRecordLayout<
@@ -2302,6 +2341,7 @@ namespace decls_block {
   using LifetimeDependenceLayout =
       BCRecordLayout<LIFETIME_DEPENDENCE,
                      BCVBR<4>,           // targetIndex
+                     BCVBR<4>,           // paramIndicesLength
                      BCFixed<1>,         // isImmortal
                      BCFixed<1>,         // hasInheritLifetimeParamIndices
                      BCFixed<1>,         // hasScopeLifetimeParamIndices
@@ -2379,33 +2419,27 @@ namespace decls_block {
     BCFixed<2>  // exclusivity mode
   >;
 
-  using ExecutionDeclAttrLayout = BCRecordLayout<
-    Execution_DECL_ATTR,
-    BCFixed<1>  // execution behavior kind
-  >;
-
   using ABIDeclAttrLayout = BCRecordLayout<
     ABI_DECL_ATTR,
     BCFixed<1>, // implicit flag
     DeclIDField // ABI decl
   >;
 
-  using AvailableDeclAttrLayout = BCRecordLayout<
-    Available_DECL_ATTR,
-    BCFixed<1>, // implicit flag
-    BCFixed<1>, // is unconditionally unavailable?
-    BCFixed<1>, // is unconditionally deprecated?
-    BCFixed<1>, // is unavailable from async?
-    BCFixed<1>, // is this PackageDescription version-specific kind?
-    BCFixed<1>, // is SPI?
-    BCFixed<1>, // is for Embedded
-    BC_AVAIL_TUPLE, // Introduced
-    BC_AVAIL_TUPLE, // Deprecated
-    BC_AVAIL_TUPLE, // Obsoleted
-    BCVBR<5>,    // platform
-    BCVBR<5>,    // number of bytes in message string
-    BCVBR<5>,    // number of bytes in rename string
-    BCBlob       // message, followed by rename
+  using AvailableDeclAttrLayout = BCRecordLayout<Available_DECL_ATTR,
+    BCFixed<1>,                   // implicit flag
+    BCFixed<1>,                   // is unconditionally unavailable?
+    BCFixed<1>,                   // is unconditionally deprecated?
+    BCFixed<1>,                   // is unavailable from async?
+    BCFixed<1>,                   // is SPI?
+    AvailabilityDomainKindField,  // kind of availability domain
+    BCVBR<5>,                     // platform kind of domain
+    DeclIDField,                  // the decl representing a custom domain
+    BC_AVAIL_TUPLE,               // introduced version
+    BC_AVAIL_TUPLE,               // deprecated version
+    BC_AVAIL_TUPLE,               // obsoleted version
+    BCVBR<5>,                     // number of bytes in message string
+    BCVBR<5>,                     // number of bytes in rename string
+    BCBlob                        // message, followed by rename
   >;
 
   using OriginallyDefinedInDeclAttrLayout = BCRecordLayout<
@@ -2434,16 +2468,18 @@ namespace decls_block {
 
   using SpecializeDeclAttrLayout = BCRecordLayout<
       Specialize_DECL_ATTR,
+      BCFixed<1>,              // isPublic flag (@specialized vs @_specialize)
       BCFixed<1>,              // exported flag
       BCFixed<1>,              // specialization kind
       GenericSignatureIDField, // specialized signature
       DeclIDField,             // target function
-      BCVBR<4>, // # of arguments (+1) or 1 if simple decl name, 0 if no target
       BCVBR<4>, // # of SPI groups
       BCVBR<4>, // # of availability attributes
-      BCVBR<4>, // # of type erased parameters
-      BCArray<IdentifierIDField> // target function pieces, spi groups, type erased params
+      BCArray<IdentifierIDField> // spi groups, type erased params
       >;
+  // Unused. We use the layout above.
+  using SpecializedDeclAttrLayout = BCRecordLayout<
+      Specialized_DECL_ATTR>;
 
   using StorageRestrictionsDeclAttrLayout = BCRecordLayout<
       StorageRestrictions_DECL_ATTR,
@@ -2462,7 +2498,6 @@ namespace decls_block {
   using DerivativeDeclAttrLayout = BCRecordLayout<
     Derivative_DECL_ATTR,
     BCFixed<1>, // Implicit flag.
-    IdentifierIDField, // Original name.
     BCFixed<1>, // Has original accessor kind?
     AccessorKindField, // Original accessor kind.
     DeclIDField, // Original function declaration.
@@ -2473,7 +2508,6 @@ namespace decls_block {
   using TransposeDeclAttrLayout = BCRecordLayout<
     Transpose_DECL_ATTR,
     BCFixed<1>, // Implicit flag.
-    IdentifierIDField, // Original name.
     DeclIDField, // Original function declaration.
     BCArray<BCFixed<1>> // Transposed parameter indices' bitvector.
   >;
@@ -2488,9 +2522,7 @@ namespace decls_block {
   using DynamicReplacementDeclAttrLayout = BCRecordLayout<
     DynamicReplacement_DECL_ATTR,
     BCFixed<1>, // implicit flag
-    DeclIDField, // replaced function
-    BCVBR<4>,   // # of arguments (+1) or zero if no name
-    BCArray<IdentifierIDField>
+    DeclIDField // replaced function
   >;
 
   using TypeEraserDeclAttrLayout = BCRecordLayout<
@@ -2520,7 +2552,7 @@ namespace decls_block {
   >;
 
   using ExposeDeclAttrLayout = BCRecordLayout<Expose_DECL_ATTR,
-                                              BCFixed<1>, // exposure kind
+                                              BCFixed<2>, // exposure kind
                                               BCFixed<1>, // implicit flag
                                               BCBlob      // declaration name
                                               >;
@@ -2543,7 +2575,13 @@ namespace decls_block {
 
   using NonisolatedDeclAttrLayout =
       BCRecordLayout<Nonisolated_DECL_ATTR,
-                     BCFixed<1>, // is the argument (unsafe)
+                     BCFixed<2>, // the modifier (unsafe, nonsending)
+                     BCFixed<1>  // implicit flag
+                     >;
+
+  using InheritActorContextDeclAttrLayout =
+       BCRecordLayout<InheritActorContext_DECL_ATTR,
+                     BCFixed<1>, // the modifier (none = 0, always = 1)
                      BCFixed<1>  // implicit flag
                      >;
 
@@ -2571,6 +2609,13 @@ namespace decls_block {
                      BCArray<BCFixed<1>> // concatenated param indices
                      >;
 
+  using NonexhaustiveDeclAttrLayout = BCRecordLayout<
+    Nonexhaustive_DECL_ATTR,
+    BCFixed<2>  // mode
+  >;
+
+  // clang-format on
+
 #undef SYNTAX_SUGAR_TYPE_LAYOUT
 #undef TYPE_LAYOUT
 #undef TYPE_LAYOUT_IMPL
diff --git a/lib/Serialization/SILFormat.h b/lib/Serialization/SILFormat.h
index 5eeefeb60d517..d433bf305d136 100644
--- a/lib/Serialization/SILFormat.h
+++ b/lib/Serialization/SILFormat.h
@@ -229,6 +229,7 @@ namespace sil_block {
     BCFixed<1>,          // Is this a declaration. We represent this separately
                          // from whether or not we have entries since we can
                          // have empty witness tables.
+    BCFixed<1>,          // Is this a specialized witness table.
     BCFixed<2>,          // SerializedKind.
     ProtocolConformanceIDField   // conformance
     // Witness table entries will be serialized after.
@@ -249,7 +250,6 @@ namespace sil_block {
   using WitnessAssocProtocolLayout = BCRecordLayout<
     SIL_WITNESS_ASSOC_PROTOCOL,
     TypeIDField, // ID of requirement subject type
-    TypeIDField, // ID of substituted subject type
     ProtocolConformanceIDField
   >;
 
@@ -261,7 +261,6 @@ namespace sil_block {
 
   using WitnessConditionalConformanceLayout = BCRecordLayout<
     SIL_WITNESS_CONDITIONAL_CONFORMANCE,
-    TypeIDField, // ID of associated type
     ProtocolConformanceIDField // ID of conformance
   >;
 
@@ -295,8 +294,10 @@ namespace sil_block {
     BCFixed<2>,          // serialized
     BCFixed<1>,          // Is this a declaration.
     BCFixed<1>,          // Is this a let variable.
+    BCFixed<1>,          // Is this marked as "used".
     TypeIDField,
-    DeclIDField
+    DeclIDField,
+    ModuleIDField        // Parent ModuleDecl *
   >;
 
   using DifferentiabilityWitnessLayout = BCRecordLayout<
@@ -375,6 +376,7 @@ namespace sil_block {
                      BCFixed<3>,  // perfConstraints
                      BCFixed<2>,  // classSubclassScope
                      BCFixed<1>,  // hasCReferences
+                     BCFixed<1>,  // markedAsUsed
                      BCFixed<3>,  // side effect info.
                      BCVBR<8>,    // number of specialize attributes
                      BCFixed<1>,  // has qualified ownership
diff --git a/lib/Serialization/SILSerializationFunctionBuilder.h b/lib/Serialization/SILSerializationFunctionBuilder.h
index a6ee2ab2759d1..8570108c5c0e6 100644
--- a/lib/Serialization/SILSerializationFunctionBuilder.h
+++ b/lib/Serialization/SILSerializationFunctionBuilder.h
@@ -1,4 +1,4 @@
-//===--- SerializationFunctionBuilder.h -----------------------------------===//
+//===--- SILSerializationFunctionBuilder.h --------------------------------===//
 //
 // This source file is part of the Swift.org open source project
 //
diff --git a/lib/Serialization/ScanningLoaders.cpp b/lib/Serialization/ScanningLoaders.cpp
index 53c1fee1355e2..a3f9f023d8bcd 100644
--- a/lib/Serialization/ScanningLoaders.cpp
+++ b/lib/Serialization/ScanningLoaders.cpp
@@ -10,6 +10,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "swift/Serialization/ScanningLoaders.h"
+#include "ModuleFile.h"
+#include "ModuleFileSharedCore.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/DiagnosticEngine.h"
 #include "swift/AST/DiagnosticSuppression.h"
@@ -20,16 +23,14 @@
 #include "swift/AST/SourceFile.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/Basic/Assertions.h"
+#include "swift/Basic/Defer.h"
 #include "swift/Basic/FileTypes.h"
 #include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Frontend/ModuleInterfaceLoader.h"
-#include "swift/Serialization/ScanningLoaders.h"
 #include "swift/Serialization/SerializedModuleLoader.h"
 #include "swift/Subsystems.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/SetOperations.h"
-#include "llvm/CAS/CachingOnDiskFileSystem.h"
-#include "llvm/Support/Error.h"
 #include "llvm/Support/PrefixMapper.h"
 #include "llvm/Support/Threading.h"
 #include "llvm/Support/VirtualFileSystem.h"
@@ -45,7 +46,7 @@ std::error_code SwiftModuleScanner::findModuleFilesInDirectory(
     std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-    bool skipBuildingInterface, bool IsFramework,
+    bool IsCanImportLookup, bool IsFramework,
     bool isTestableDependencyLookup) {
   using namespace llvm::sys;
 
@@ -60,77 +61,65 @@ std::error_code SwiftModuleScanner::findModuleFilesInDirectory(
       isTestableDependencyLookup || !InPath) {
     if (fs.exists(ModPath)) {
       // The module file will be loaded directly.
-      auto dependencies =
-          scanModuleFile(ModPath, IsFramework,
-                         isTestableDependencyLookup,
-                         /* isCandidateForTextualModule */ false);
-      if (dependencies) {
-        this->dependencies = std::move(dependencies.get());
+      auto dependencyInfo = scanBinaryModuleFile(
+          ModuleID.Item, ModPath, IsFramework, isTestableDependencyLookup,
+          /* isCandidateForTextualModule */ false);
+      if (dependencyInfo) {
+        this->foundDependencyInfo = std::move(dependencyInfo.get());
         return std::error_code();
       }
-      return dependencies.getError();
+      return dependencyInfo.getError();
     }
     return std::make_error_code(std::errc::no_such_file_or_directory);
   }
   assert(InPath);
 
-  auto dependencies =
-      scanInterfaceFile(*InPath, IsFramework, isTestableDependencyLookup);
-  if (dependencies) {
-    this->dependencies = std::move(dependencies.get());
+  auto dependencyInfo = scanInterfaceFile(ModuleID.Item, *InPath, IsFramework,
+                                          isTestableDependencyLookup);
+  if (dependencyInfo) {
+    this->foundDependencyInfo = std::move(dependencyInfo.get());
     return std::error_code();
   }
-  return dependencies.getError();
+  return dependencyInfo.getError();
 }
 
-bool PlaceholderSwiftModuleScanner::findModule(
-    ImportPath::Element moduleID, SmallVectorImpl<char> *moduleInterfacePath,
-    SmallVectorImpl<char> *moduleInterfaceSourcePath,
-    std::unique_ptr<llvm::MemoryBuffer> *moduleBuffer,
-    std::unique_ptr<llvm::MemoryBuffer> *moduleDocBuffer,
-    std::unique_ptr<llvm::MemoryBuffer> *moduleSourceInfoBuffer,
-    bool skipBuildingInterface, bool isTestableDependencyLookup,
-    bool &isFramework, bool &isSystemModule) {
-  StringRef moduleName = Ctx.getRealModuleName(moduleID.Item).str();
-  auto it = PlaceholderDependencyModuleMap.find(moduleName);
-  if (it == PlaceholderDependencyModuleMap.end()) {
+bool SwiftModuleScanner::canImportModule(
+    ImportPath::Module path, SourceLoc loc, ModuleVersionInfo *versionInfo,
+    bool isTestableDependencyLookup) {
+  if (path.hasSubmodule())
     return false;
+
+  // Check explicitly-provided Swift modules with '-swift-module-file'
+  ImportPath::Element mID = path.front();
+  auto it =
+      explicitSwiftModuleInputs.find(Ctx.getRealModuleName(mID.Item).str());
+  if (it != explicitSwiftModuleInputs.end()) {
+    auto dependencyInfo = scanBinaryModuleFile(
+        mID.Item, it->getValue(), /* isFramework */ false,
+        isTestableDependencyLookup, /* isCandidateForTextualModule */ false);
+    if (dependencyInfo) {
+      this->foundDependencyInfo = std::move(dependencyInfo.get());
+      return true;
+    }
   }
-  auto &moduleInfo = it->getValue();
-  auto dependencies = ModuleDependencyInfo::forPlaceholderSwiftModuleStub(
-      moduleInfo.modulePath,
-      moduleInfo.moduleDocPath.has_value() ? moduleInfo.moduleDocPath.value()
-                                           : "",
-      moduleInfo.moduleSourceInfoPath.has_value()
-          ? moduleInfo.moduleSourceInfoPath.value()
-          : "");
-  this->dependencies = std::move(dependencies);
-  return true;
+
+  return SerializedModuleLoaderBase::canImportModule(
+      path, loc, versionInfo, isTestableDependencyLookup);
 }
 
-void PlaceholderSwiftModuleScanner::parsePlaceholderModuleMap(
-    StringRef fileName) {
-  ExplicitModuleMapParser parser(Allocator);
-  llvm::StringMap<ExplicitClangModuleInputInfo> ClangDependencyModuleMap;
-  llvm::StringMap<std::string> ModuleAliases;
-  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> fileBufOrErr =
-      llvm::MemoryBuffer::getFile(fileName);
-  if (!fileBufOrErr) {
-    Ctx.Diags.diagnose(SourceLoc(), diag::explicit_swift_module_map_missing,
-                       fileName);
-    return;
-  }
-  auto result = parser.parseSwiftExplicitModuleMap(
-      (*fileBufOrErr)->getMemBufferRef(), PlaceholderDependencyModuleMap,
-      ClangDependencyModuleMap, ModuleAliases);
-  if (result == std::errc::invalid_argument) {
-    Ctx.Diags.diagnose(SourceLoc(),
-                       diag::placeholder_dependency_module_map_corrupted,
-                       fileName);
-  } else if (result == std::errc::no_such_file_or_directory) {
-    Ctx.Diags.diagnose(
-        SourceLoc(), diag::placeholder_dependency_module_map_missing, fileName);
-  }
+bool SwiftModuleScanner::handlePossibleTargetMismatch(
+    SourceLoc sourceLocation, StringRef moduleName,
+    const SerializedModuleBaseName &absoluteBaseName,
+    bool isCanImportLookup) {
+  std::vector<std::string> foundIncompatibleArchModules;
+  identifyArchitectureVariants(Ctx, absoluteBaseName,
+                               foundIncompatibleArchModules);
+
+  for (const auto &modulePath : foundIncompatibleArchModules)
+    incompatibleCandidates.push_back({modulePath,
+                                      "invalid architecture"});
+
+  return false;
 }
 
 static std::vector<std::string> getCompiledCandidates(ASTContext &ctx,
@@ -142,13 +131,14 @@ static std::vector<std::string> getCompiledCandidates(ASTContext &ctx,
 }
 
 llvm::ErrorOr<ModuleDependencyInfo>
-SwiftModuleScanner::scanInterfaceFile(Twine moduleInterfacePath,
+SwiftModuleScanner::scanInterfaceFile(Identifier moduleID,
+                                      Twine moduleInterfacePath,
                                       bool isFramework, bool isTestableImport) {
   // Create a module filename.
   // FIXME: Query the module interface loader to determine an appropriate
   // name for the module, which includes an appropriate hash.
   auto newExt = file_types::getExtension(file_types::TY_SwiftModuleFile);
-  auto realModuleName = Ctx.getRealModuleName(moduleName);
+  auto realModuleName = Ctx.getRealModuleName(moduleID);
   StringRef sdkPath = Ctx.SearchPathOpts.getSDKPath();
   llvm::SmallString<32> modulePath = realModuleName.str();
   llvm::sys::path::replace_extension(modulePath, newExt);
@@ -167,9 +157,9 @@ SwiftModuleScanner::scanInterfaceFile(Twine moduleInterfacePath,
             Ctx.SearchPathOpts.ScannerModuleValidation) {
           assert(compiledCandidates.size() == 1 &&
                  "Should only have 1 candidate module");
-          auto BinaryDep = scanModuleFile(compiledCandidates[0],
-                                          isFramework, isTestableImport,
-                                          /* isCandidateForTextualModule */ true);
+          auto BinaryDep = scanBinaryModuleFile(
+              moduleID, compiledCandidates[0], isFramework, isTestableImport,
+              /* isCandidateForTextualModule */ true);
           if (BinaryDep) {
             Result = *BinaryDep;
             return std::error_code();
@@ -187,20 +177,8 @@ SwiftModuleScanner::scanInterfaceFile(Twine moduleInterfacePath,
 
         // Handle clang arguments. For caching build, all arguments are passed
         // with `-direct-clang-cc1-module-build`.
-        if (Ctx.ClangImporterOpts.ClangImporterDirectCC1Scan) {
-          Args.push_back("-direct-clang-cc1-module-build");
-          auto *importer =
-              static_cast<ClangImporter *>(Ctx.getClangModuleLoader());
-          for (auto &Arg : importer->getSwiftExplicitModuleDirectCC1Args()) {
-            Args.push_back("-Xcc");
-            Args.push_back(Arg);
-          }
-        } else {
-          Args.push_back("-Xcc");
-          Args.push_back("-fno-implicit-modules");
-          Args.push_back("-Xcc");
-          Args.push_back("-fno-implicit-module-maps");
-        }
+        llvm::append_range(Args, swiftModuleClangCC1CommandLineArgs);
+
         for (const auto &candidate : compiledCandidates) {
           Args.push_back("-candidate-module-file");
           Args.push_back(candidate);
@@ -222,8 +200,8 @@ SwiftModuleScanner::scanInterfaceFile(Twine moduleInterfacePath,
         auto sourceFile = new (Ctx) SourceFile(
             *moduleDecl, SourceFileKind::Interface, bufferID, parsingOpts);
         std::vector<StringRef> ArgsRefs(Args.begin(), Args.end());
-        std::vector<StringRef> compiledCandidatesRefs(compiledCandidates.begin(),
-                                                      compiledCandidates.end());
+        std::vector<StringRef> compiledCandidatesRefs(
+            compiledCandidates.begin(), compiledCandidates.end());
 
         // If this interface specified '-autolink-force-load', add it to the
         // set of linked libraries for this module.
@@ -232,10 +210,11 @@ SwiftModuleScanner::scanInterfaceFile(Twine moduleInterfacePath,
           std::string linkName = realModuleName.str().str();
           auto linkNameArgIt = llvm::find(ArgsRefs, "-module-link-name");
           if (linkNameArgIt != ArgsRefs.end())
-            linkName = *(linkNameArgIt+1);
-          linkLibraries.push_back({linkName,
-                                   isFramework ? LibraryKind::Framework : LibraryKind::Library,
-                                   /*static=*/false, /*force_load=*/true});
+            linkName = *(linkNameArgIt + 1);
+          linkLibraries.push_back(
+              {linkName,
+               isFramework ? LibraryKind::Framework : LibraryKind::Library,
+               /*static=*/false, /*force_load=*/true});
         }
         bool isStatic = llvm::find(ArgsRefs, "-static") != ArgsRefs.end();
 
@@ -243,16 +222,6 @@ SwiftModuleScanner::scanInterfaceFile(Twine moduleInterfacePath,
             InPath, compiledCandidatesRefs, ArgsRefs, {}, {}, linkLibraries,
             isFramework, isStatic, {}, /*module-cache-key*/ "", UserModVer);
 
-        if (Ctx.CASOpts.EnableCaching) {
-          std::vector<std::string> clangDependencyFiles;
-          auto clangImporter =
-              static_cast<ClangImporter *>(Ctx.getClangModuleLoader());
-          clangImporter->addClangInvovcationDependencies(clangDependencyFiles);
-          llvm::for_each(clangDependencyFiles, [&](std::string &file) {
-            Result->addAuxiliaryFile(file);
-          });
-        }
-
         // Walk the source file to find the import declarations.
         llvm::StringSet<> alreadyAddedModules;
         Result->addModuleImports(*sourceFile, alreadyAddedModules,
@@ -262,39 +231,44 @@ SwiftModuleScanner::scanInterfaceFile(Twine moduleInterfacePath,
         // printed in the interface file, e.g. SwiftOnoneSupport.
         auto &imInfo = mainMod->getImplicitImportInfo();
         for (auto import : imInfo.AdditionalUnloadedImports) {
-          Result->addModuleImport(import.module.getModulePath(),
-                                  import.options.contains(ImportFlags::Exported),
-                                  &alreadyAddedModules, &Ctx.SourceMgr);
+          Result->addModuleImport(
+              import.module.getModulePath(),
+              import.options.contains(ImportFlags::Exported),
+              import.accessLevel, &alreadyAddedModules, &Ctx.SourceMgr);
         }
 
-        // If this is a dependency that belongs to the same package, and we have not yet enabled Package Textual interfaces,
-        // scan the adjacent binary module for package dependencies.
+        // If this is a dependency that belongs to the same package, and we have
+        // not yet enabled Package Textual interfaces, scan the adjacent binary
+        // module for package dependencies.
         if (!ScannerPackageName.empty() &&
             !Ctx.LangOpts.EnablePackageInterfaceLoad) {
-           auto adjacentBinaryModule = std::find_if(
-               compiledCandidates.begin(), compiledCandidates.end(),
-               [moduleInterfacePath](const std::string &candidate) {
-                 return llvm::sys::path::parent_path(candidate) ==
-                        llvm::sys::path::parent_path(moduleInterfacePath.str());
-               });
-
-           if (adjacentBinaryModule != compiledCandidates.end()) {
-             auto adjacentBinaryModulePackageOnlyImports = getMatchingPackageOnlyImportsOfModule(
-                  *adjacentBinaryModule, isFramework,
-                  isRequiredOSSAModules(), Ctx.LangOpts.SDKName,
-                  ScannerPackageName, Ctx.SourceMgr.getFileSystem().get(),
-                  Ctx.SearchPathOpts.DeserializedPathRecoverer);
-
-             if (!adjacentBinaryModulePackageOnlyImports)
-               return adjacentBinaryModulePackageOnlyImports.getError();
-
-             for (const auto &requiredImport : *adjacentBinaryModulePackageOnlyImports)
-               if (!alreadyAddedModules.contains(requiredImport.importIdentifier))
-                 Result->addModuleImport(requiredImport.importIdentifier,
-                                         requiredImport.isExported,
-                                         &alreadyAddedModules);
-           }
-         }
+          auto adjacentBinaryModule = std::find_if(
+              compiledCandidates.begin(), compiledCandidates.end(),
+              [moduleInterfacePath](const std::string &candidate) {
+                return llvm::sys::path::parent_path(candidate) ==
+                       llvm::sys::path::parent_path(moduleInterfacePath.str());
+              });
+
+          if (adjacentBinaryModule != compiledCandidates.end()) {
+            auto adjacentBinaryModulePackageOnlyImports =
+                getMatchingPackageOnlyImportsOfModule(
+                    *adjacentBinaryModule, isFramework,
+                    Ctx.LangOpts.SDKName, Ctx.LangOpts.Target,
+                    ScannerPackageName, Ctx.SourceMgr.getFileSystem().get(),
+                    Ctx.SearchPathOpts.DeserializedPathRecoverer);
+
+            if (!adjacentBinaryModulePackageOnlyImports)
+              return adjacentBinaryModulePackageOnlyImports.getError();
+
+            for (const auto &requiredImport :
+                 *adjacentBinaryModulePackageOnlyImports)
+              if (!alreadyAddedModules.contains(
+                      requiredImport.importIdentifier))
+                Result->addModuleImport(
+                    requiredImport.importIdentifier, requiredImport.isExported,
+                    requiredImport.accessLevel, &alreadyAddedModules);
+          }
+        }
 
         return std::error_code();
       });
@@ -305,48 +279,112 @@ SwiftModuleScanner::scanInterfaceFile(Twine moduleInterfacePath,
   return *Result;
 }
 
-ModuleDependencyVector SerializedModuleLoaderBase::getModuleDependencies(
-    Identifier moduleName, StringRef moduleOutputPath,
-    StringRef sdkModuleOutputPath,
-    const llvm::DenseSet<clang::tooling::dependencies::ModuleID>
-        &alreadySeenClangModules,
-    clang::tooling::dependencies::DependencyScanningTool &clangScanningTool,
-    InterfaceSubContextDelegate &delegate, llvm::PrefixMapper *mapper,
-    bool isTestableDependencyLookup) {
-  ImportPath::Module::Builder builder(moduleName);
-  auto modulePath = builder.get();
-  auto moduleId = modulePath.front().Item;
-
-  // Instantiate dependency scanning "loaders".
-  SmallVector<std::unique_ptr<SwiftModuleScanner>, 2> scanners;
-  // Placeholder dependencies must be resolved first, to prevent the
-  // ModuleDependencyScanner from first discovering artifacts of a previous
-  // build. Such artifacts are captured as compiledModuleCandidates in the
-  // dependency graph of the placeholder dependency module itself.
-  // FIXME: submodules?
-  scanners.push_back(std::make_unique<PlaceholderSwiftModuleScanner>(
-      Ctx, LoadMode, moduleId, Ctx.SearchPathOpts.PlaceholderDependencyModuleMap,
-      delegate, moduleOutputPath, sdkModuleOutputPath));
-  scanners.push_back(std::make_unique<SwiftModuleScanner>(
-      Ctx, LoadMode, moduleId, delegate, moduleOutputPath, sdkModuleOutputPath,
-      SwiftModuleScanner::MDS_plain));
-
-  // Check whether there is a module with this name that we can import.
-  assert(isa<PlaceholderSwiftModuleScanner>(scanners[0].get()) &&
-         "Expected PlaceholderSwiftModuleScanner as the first dependency "
-         "scanner loader.");
-  for (auto &scanner : scanners) {
-    if (scanner->canImportModule(modulePath, SourceLoc(), nullptr,
-                                 isTestableDependencyLookup)) {
-
-      ModuleDependencyVector moduleDependnecies;
-      moduleDependnecies.push_back(
-          std::make_pair(ModuleDependencyID{moduleName.str().str(),
-                                            scanner->dependencies->getKind()},
-                         *(scanner->dependencies)));
-      return moduleDependnecies;
+llvm::ErrorOr<ModuleDependencyInfo> SwiftModuleScanner::scanBinaryModuleFile(
+    Identifier moduleID, Twine binaryModulePath, bool isFramework,
+    bool isTestableImport, bool isCandidateForTextualModule) {
+  const std::string moduleDocPath;
+  const std::string sourceInfoPath;
+
+  // Read and valid module.
+  auto moduleBuf =
+      Ctx.SourceMgr.getFileSystem()->getBufferForFile(binaryModulePath);
+  if (!moduleBuf)
+    return moduleBuf.getError();
+
+  std::shared_ptr<const ModuleFileSharedCore> loadedModuleFile;
+  serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
+      "", "", std::move(moduleBuf.get()), nullptr, nullptr, isFramework,
+      Ctx.LangOpts.SDKName, Ctx.LangOpts.Target,
+      Ctx.SearchPathOpts.DeserializedPathRecoverer, loadedModuleFile);
+
+  if (Ctx.SearchPathOpts.ScannerModuleValidation) {
+    // If failed to load, just ignore and return do not found.
+    if (auto loadFailureReason = invalidModuleReason(loadInfo.status)) {
+      // If no textual interface was found, then for this dependency
+      // scanning query this was *the* module discovered, which means
+      // it would be helpful to let the user know why the scanner
+      // was not able to use it because the scan will ultimately fail to
+      // resolve this dependency due to this incompatibility.
+      incompatibleCandidates.push_back({binaryModulePath.str(),
+                                        loadFailureReason.value()});
+      return std::make_error_code(std::errc::no_such_file_or_directory);
     }
+
+    if (isTestableImport && !loadedModuleFile->isTestable()) {
+      incompatibleCandidates.push_back({binaryModulePath.str(),
+                                        "module built without '-enable-testing'"});
+      return std::make_error_code(std::errc::no_such_file_or_directory);
+    }
+  }
+
+  auto binaryModuleImports =
+      getImportsOfModule(*loadedModuleFile, ModuleLoadingBehavior::Required,
+                         Ctx.LangOpts.PackageName, isTestableImport);
+
+  // Lookup optional imports of this module also
+  auto binaryModuleOptionalImports =
+      getImportsOfModule(*loadedModuleFile, ModuleLoadingBehavior::Optional,
+                         Ctx.LangOpts.PackageName, isTestableImport);
+
+  std::vector<LinkLibrary> linkLibraries;
+  {
+    linkLibraries.reserve(loadedModuleFile->getLinkLibraries().size());
+    llvm::copy(loadedModuleFile->getLinkLibraries(),
+               std::back_inserter(linkLibraries));
+    if (loadedModuleFile->isFramework())
+      linkLibraries.emplace_back(loadedModuleFile->getName(),
+                                 LibraryKind::Framework,
+                                 loadedModuleFile->isStaticLibrary());
   }
 
-  return {};
+  // Attempt to resolve the module's defining .swiftinterface path
+  std::string definingModulePath =
+      loadedModuleFile->resolveModuleDefiningFilePath(
+          Ctx.SearchPathOpts.getSDKPath());
+
+  std::string userModuleVer =
+      loadedModuleFile->getUserModuleVersion().getAsString();
+  std::vector<serialization::SearchPath> serializedSearchPaths;
+  llvm::copy(loadedModuleFile->getSearchPaths(),
+             std::back_inserter(serializedSearchPaths));
+
+  // Map the set of dependencies over to the "module dependencies".
+  auto dependencies = ModuleDependencyInfo::forSwiftBinaryModule(
+      binaryModulePath.str(), moduleDocPath, sourceInfoPath,
+      binaryModuleImports->moduleImports,
+      binaryModuleOptionalImports->moduleImports, linkLibraries,
+      serializedSearchPaths, binaryModuleImports->headerImport,
+      definingModulePath, isFramework, loadedModuleFile->isStaticLibrary(),
+      loadedModuleFile->isBuiltWithCxxInterop(),
+      /*module-cache-key*/ "", userModuleVer);
+
+  for (auto &macro : loadedModuleFile->getExternalMacros()) {
+    auto deps =
+        resolveMacroPlugin(macro, loadedModuleFile->getModulePackageName());
+    if (!deps)
+      continue;
+    dependencies.addMacroDependency(macro.ModuleName, deps->LibraryPath,
+                                    deps->ExecutablePath);
+  }
+
+  return std::move(dependencies);
+}
+
+SwiftModuleScannerQueryResult
+SwiftModuleScanner::lookupSwiftModule(Identifier moduleName,
+                                      bool isTestableImport) {
+  // When we exit, ensure we clear dependencies discovered on this query
+  SWIFT_DEFER {
+    foundDependencyInfo = std::nullopt;
+    incompatibleCandidates = {};
+  };
+
+  ImportPath::Module::Builder builder(moduleName);
+  auto modulePath = builder.get();
+  // Execute the check to determine whether there is a module with this name
+  // that we can import. This check will populate the result fields if one is
+  // found.
+  canImportModule(modulePath, SourceLoc(), nullptr, isTestableImport);
+  return SwiftModuleScannerQueryResult(
+      std::move(foundDependencyInfo), std::move(incompatibleCandidates));
 }
diff --git a/lib/Serialization/Serialization.cpp b/lib/Serialization/Serialization.cpp
index 5fcd564217888..7aad48c8bce7b 100644
--- a/lib/Serialization/Serialization.cpp
+++ b/lib/Serialization/Serialization.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -17,6 +17,7 @@
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/ASTVisitor.h"
 #include "swift/AST/AutoDiff.h"
+#include "swift/AST/Decl.h"
 #include "swift/AST/DiagnosticsCommon.h"
 #include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/Expr.h"
@@ -41,11 +42,13 @@
 #include "swift/AST/SynthesizedFileUnit.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/AST/TypeVisitor.h"
+#include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/FileSystem.h"
 #include "swift/Basic/LLVMExtras.h"
 #include "swift/Basic/PathRemapper.h"
+#include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Basic/STLExtras.h"
 #include "swift/Basic/Version.h"
 #include "swift/ClangImporter/ClangImporter.h"
@@ -491,7 +494,7 @@ namespace {
 static ModuleDecl *getModule(ModuleOrSourceFile DC) {
   if (auto M = DC.dyn_cast<ModuleDecl *>())
     return M;
-  return DC.get<SourceFile *>()->getParentModule();
+  return cast<SourceFile *>(DC)->getParentModule();
 }
 
 static bool shouldSerializeAsLocalContext(const DeclContext *DC) {
@@ -532,6 +535,7 @@ static uint8_t getRawReadImplKind(swift::ReadImplKind kind) {
   CASE(Address)
   CASE(Read)
   CASE(Read2)
+  CASE(Borrow)
 #undef CASE
   }
   llvm_unreachable("bad kind");
@@ -550,6 +554,7 @@ static unsigned getRawWriteImplKind(swift::WriteImplKind kind) {
   CASE(MutableAddress)
   CASE(Modify)
   CASE(Modify2)
+  CASE(Mutate)
 #undef CASE
   }
   llvm_unreachable("bad kind");
@@ -568,6 +573,7 @@ static unsigned getRawReadWriteImplKind(swift::ReadWriteImplKind kind) {
   CASE(Modify2)
   CASE(StoredWithDidSet)
   CASE(InheritedWithDidSet)
+  CASE(Mutate)
 #undef CASE
   }
   llvm_unreachable("bad kind");
@@ -836,7 +842,6 @@ void Serializer::writeBlockInfoBlock() {
   BLOCK_RECORD(control_block, TARGET);
   BLOCK_RECORD(control_block, SDK_NAME);
   BLOCK_RECORD(control_block, REVISION);
-  BLOCK_RECORD(control_block, IS_OSSA);
   BLOCK_RECORD(control_block, ALLOWABLE_CLIENT_NAME);
   BLOCK_RECORD(control_block, CHANNEL);
   BLOCK_RECORD(control_block, SDK_VERSION);
@@ -863,6 +868,7 @@ void Serializer::writeBlockInfoBlock() {
   BLOCK_RECORD(options_block, ALLOW_NON_RESILIENT_ACCESS);
   BLOCK_RECORD(options_block, SERIALIZE_PACKAGE_ENABLED);
   BLOCK_RECORD(options_block, STRICT_MEMORY_SAFETY);
+  BLOCK_RECORD(options_block, DEFERRED_CODE_GEN);
   BLOCK_RECORD(options_block, CXX_STDLIB_KIND);
   BLOCK_RECORD(options_block, PUBLIC_MODULE_NAME);
   BLOCK_RECORD(options_block, SWIFT_INTERFACE_COMPILER_VERSION);
@@ -1011,7 +1017,6 @@ void Serializer::writeHeader() {
     control_block::SDKVersionLayout SDKVersion(Out);
     control_block::RevisionLayout Revision(Out);
     control_block::ChannelLayout Channel(Out);
-    control_block::IsOSSALayout IsOSSA(Out);
     control_block::AllowableClientLayout Allowable(Out);
 
     // Write module 'real name', which can be different from 'name'
@@ -1068,8 +1073,6 @@ void Serializer::writeHeader() {
 
     Channel.emit(ScratchRecord, version::getCurrentCompilerChannel());
 
-    IsOSSA.emit(ScratchRecord, Options.IsOSSA);
-
     {
       llvm::BCBlockRAII restoreBlock(Out, OPTIONS_BLOCK_ID, 4);
 
@@ -1176,6 +1179,11 @@ void Serializer::writeHeader() {
         StrictMemorySafety.emit(ScratchRecord);
       }
 
+      if (M->deferredCodeGen()) {
+        options_block::DeferredCodeGenLayout DeferredCodeGen(Out);
+        DeferredCodeGen.emit(ScratchRecord);
+      }
+
       if (M->hasCxxInteroperability()) {
         options_block::HasCxxInteroperabilityEnabledLayout
             CxxInteroperabilityEnabled(Out);
@@ -1186,21 +1194,18 @@ void Serializer::writeHeader() {
                            static_cast<uint8_t>(M->getCXXStdlibKind()));
       }
 
-      if (M->supportsExtensibleEnums()) {
-        options_block::ExtensibleEnumsLayout ExtensibleEnums(Out);
-        ExtensibleEnums.emit(ScratchRecord);
-      }
-
       if (Options.SerializeOptionsForDebugging) {
         options_block::SDKPathLayout SDKPath(Out);
         options_block::XCCLayout XCC(Out);
 
         const auto &PathRemapper = Options.DebuggingOptionsPrefixMap;
         const auto &PathObfuscator = Options.PathObfuscator;
+        auto remapPath = [&PathRemapper, &PathObfuscator](StringRef Path) {
+          return PathObfuscator.obfuscate(PathRemapper.remapPath(Path));
+        };
+
         auto sdkPath = M->getASTContext().SearchPathOpts.getSDKPath();
-        SDKPath.emit(
-            ScratchRecord,
-            PathObfuscator.obfuscate(PathRemapper.remapPath(sdkPath)));
+        SDKPath.emit(ScratchRecord, remapPath(sdkPath));
         auto &Opts = Options.ExtraClangOptions;
         for (auto Arg = Opts.begin(), E = Opts.end(); Arg != E; ++Arg) {
           StringRef arg(*Arg);
@@ -1244,7 +1249,7 @@ void Serializer::writeHeader() {
             auto &opt = elem.get<PluginSearchOption::PluginPath>();
             PluginSearchOpt.emit(ScratchRecord,
                                  uint8_t(PluginSearchOptionKind::PluginPath),
-                                 opt.SearchPath);
+                                 remapPath(opt.SearchPath));
             continue;
           }
           case PluginSearchOption::Kind::ExternalPluginPath: {
@@ -1252,7 +1257,7 @@ void Serializer::writeHeader() {
             PluginSearchOpt.emit(
                 ScratchRecord,
                 uint8_t(PluginSearchOptionKind::ExternalPluginPath),
-                opt.SearchPath + "#" + opt.ServerPath);
+                remapPath(opt.SearchPath) + "#" + remapPath(opt.ServerPath));
             continue;
           }
           case PluginSearchOption::Kind::LoadPluginLibrary: {
@@ -1260,12 +1265,12 @@ void Serializer::writeHeader() {
             PluginSearchOpt.emit(
                 ScratchRecord,
                 uint8_t(PluginSearchOptionKind::LoadPluginLibrary),
-                opt.LibraryPath);
+                remapPath(opt.LibraryPath));
             continue;
           }
           case PluginSearchOption::Kind::LoadPluginExecutable: {
             auto &opt = elem.get<PluginSearchOption::LoadPluginExecutable>();
-            std::string optStr = opt.ExecutablePath + "#";
+            std::string optStr = remapPath(opt.ExecutablePath) + "#";
             llvm::interleave(
                 opt.ModuleNames, [&](auto &name) { optStr += name; },
                 [&]() { optStr += ","; });
@@ -1276,8 +1281,8 @@ void Serializer::writeHeader() {
           }
           case PluginSearchOption::Kind::ResolvedPluginConfig: {
             auto &opt = elem.get<PluginSearchOption::ResolvedPluginConfig>();
-            std::string optStr =
-                opt.LibraryPath + "#" + opt.ExecutablePath + "#";
+            std::string optStr = remapPath(opt.LibraryPath) + "#" +
+                                 remapPath(opt.ExecutablePath) + "#";
             llvm::interleave(
                 opt.ModuleNames, [&](auto &name) { optStr += name; },
                 [&]() { optStr += ","; });
@@ -1790,7 +1795,7 @@ void Serializer::writeASTBlockEntity(const GenericEnvironment *genericEnv) {
   assert(GenericEnvironmentsToSerialize.hasRef(genericEnv));
 
   switch (genericEnv->getKind()) {
-  case GenericEnvironment::Kind::OpenedExistential: {
+  case GenericEnvironment::Kind::Existential: {
     auto kind = GenericEnvironmentKind::OpenedExistential;
     auto existentialTypeID = addTypeRef(genericEnv->getOpenedExistentialType());
     auto parentSigID = addGenericSignatureRef(genericEnv->getGenericSignature());
@@ -1804,7 +1809,7 @@ void Serializer::writeASTBlockEntity(const GenericEnvironment *genericEnv) {
     return;
   }
 
-  case GenericEnvironment::Kind::OpenedElement: {
+  case GenericEnvironment::Kind::Element: {
     auto kind = GenericEnvironmentKind::OpenedElement;
     auto shapeClassID = addTypeRef(genericEnv->getOpenedElementShapeClass());
     auto parentSigID = addGenericSignatureRef(genericEnv->getGenericSignature());
@@ -2150,6 +2155,7 @@ static bool shouldSerializeMember(Decl *D) {
   case DeclKind::Extension:
   case DeclKind::Module:
   case DeclKind::PrecedenceGroup:
+  case DeclKind::Using:
     if (D->getASTContext().LangOpts.AllowModuleWithCompilerErrors)
       return false;
     llvm_unreachable("decl should never be a member");
@@ -2196,8 +2202,9 @@ static bool shouldSerializeMember(Decl *D) {
 
 static serialization::AccessorKind getStableAccessorKind(swift::AccessorKind K){
   switch (K) {
-#define ACCESSOR(ID) \
-  case swift::AccessorKind::ID: return serialization::ID;
+#define ACCESSOR(ID, KEYWORD)                                                  \
+  case swift::AccessorKind::ID:                                                \
+    return serialization::ID;
 #include "swift/AST/AccessorKinds.def"
   }
 
@@ -2737,10 +2744,10 @@ void Serializer::writeLifetimeDependencies(
 
     auto abbrCode = DeclTypeAbbrCodes[LifetimeDependenceLayout::Code];
     LifetimeDependenceLayout::emitRecord(
-        Out, ScratchRecord, abbrCode, info.getTargetIndex(), info.isImmortal(),
+        Out, ScratchRecord, abbrCode, info.getTargetIndex(),
+        info.getParamIndicesLength(), info.isImmortal(),
         info.hasInheritLifetimeParamIndices(),
-        info.hasScopeLifetimeParamIndices(),
-        info.hasAddressableParamIndices(),
+        info.hasScopeLifetimeParamIndices(), info.hasAddressableParamIndices(),
         paramIndices);
     paramIndices.clear();
   }
@@ -2942,15 +2949,6 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
   }
 #include "swift/AST/DeclAttr.def"
 
-    case DeclAttrKind::Execution: {
-      auto *theAttr = cast<ExecutionAttr>(DA);
-      auto abbrCode = S.DeclTypeAbbrCodes[ExecutionDeclAttrLayout::Code];
-      ExecutionDeclAttrLayout::emitRecord(
-          S.Out, S.ScratchRecord, abbrCode,
-          static_cast<uint8_t>(theAttr->getBehavior()));
-      return;
-    }
-
     case DeclAttrKind::ABI: {
       auto *theAttr = cast<ABIAttr>(DA);
       auto abbrCode = S.DeclTypeAbbrCodes[ABIDeclAttrLayout::Code];
@@ -2997,6 +2995,7 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
       auto abbrCode = S.DeclTypeAbbrCodes[CDeclDeclAttrLayout::Code];
       CDeclDeclAttrLayout::emitRecord(S.Out, S.ScratchRecord, abbrCode,
                                       theAttr->isImplicit(),
+                                      theAttr->Underscored,
                                       theAttr->Name);
       return;
     }
@@ -3096,19 +3095,19 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
 
     case DeclAttrKind::OriginallyDefinedIn: {
       auto *theAttr = cast<OriginallyDefinedInAttr>(DA);
-      ENCODE_VER_TUPLE(
-          Moved, std::optional<llvm::VersionTuple>(theAttr->MovedVersion));
+      ENCODE_VER_TUPLE(Moved, std::optional<llvm::VersionTuple>(
+                                  theAttr->getParsedMovedVersion()));
       auto abbrCode = S.DeclTypeAbbrCodes[OriginallyDefinedInDeclAttrLayout::Code];
       llvm::SmallString<32> blob;
-      blob.append(theAttr->ManglingModuleName.str());
+      blob.append(theAttr->getManglingModuleName().str());
       blob.push_back('\0');
-      blob.append(theAttr->LinkerModuleName.str());
+      blob.append(theAttr->getLinkerModuleName().str());
       blob.push_back('\0');
       OriginallyDefinedInDeclAttrLayout::emitRecord(
           S.Out, S.ScratchRecord, abbrCode,
           theAttr->isImplicit(),
           LIST_VER_TUPLE_PIECES(Moved),
-          static_cast<unsigned>(theAttr->Platform),
+          static_cast<unsigned>(theAttr->getPlatform()),
           blob);
       return;
     }
@@ -3129,7 +3128,28 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
              !theAttr->getParsedAttr()->hasCachedRenamedDecl());
       auto domain = theAttr->getDomain();
 
-      // FIXME: [availability] Serialize domain and kind directly.
+      auto getDomainKind = [](AvailabilityDomain domain) -> AvailabilityDomainKind {
+        switch (domain.getKind()) {
+          case AvailabilityDomain::Kind::Universal:
+            return AvailabilityDomainKind::Universal;
+          case AvailabilityDomain::Kind::SwiftLanguageMode:
+            return AvailabilityDomainKind::SwiftLanguageMode;
+          case AvailabilityDomain::Kind::SwiftRuntime:
+            return AvailabilityDomainKind::SwiftRuntime;
+          case AvailabilityDomain::Kind::PackageDescription:
+            return AvailabilityDomainKind::PackageDescription;
+          case AvailabilityDomain::Kind::Embedded:
+            return AvailabilityDomainKind::Embedded;
+          case AvailabilityDomain::Kind::Platform:
+            return AvailabilityDomainKind::Platform;
+          case AvailabilityDomain::Kind::Custom:
+            return AvailabilityDomainKind::Custom;
+        }
+      };
+
+      auto domainKind = getDomainKind(domain);
+      const Decl *domainDecl = domain.getDecl();
+
       llvm::SmallString<32> blob;
       blob.append(theAttr->getMessage());
       blob.append(theAttr->getRename());
@@ -3140,13 +3160,13 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
           theAttr->isUnconditionallyUnavailable(),
           theAttr->isUnconditionallyDeprecated(),
           theAttr->isNoAsync(),
-          domain.isPackageDescription(),
           theAttr->isSPI(),
-          domain.isEmbedded(),
+          static_cast<uint8_t>(domainKind),
+          static_cast<unsigned>(domain.getPlatformKind()),
+          S.addDeclRef(domainDecl),
           LIST_VER_TUPLE_PIECES(Introduced),
           LIST_VER_TUPLE_PIECES(Deprecated),
           LIST_VER_TUPLE_PIECES(Obsoleted),
-          static_cast<unsigned>(domain.getPlatformKind()),
           theAttr->getMessage().size(),
           theAttr->getRename().size(),
           blob);
@@ -3155,14 +3175,14 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
 
     case DeclAttrKind::BackDeployed: {
       auto *theAttr = cast<BackDeployedAttr>(DA);
-      ENCODE_VER_TUPLE(Version,
-                       std::optional<llvm::VersionTuple>(theAttr->Version));
+      ENCODE_VER_TUPLE(
+          Version, std::optional<llvm::VersionTuple>(theAttr->getVersion()));
       auto abbrCode = S.DeclTypeAbbrCodes[BackDeployedDeclAttrLayout::Code];
       BackDeployedDeclAttrLayout::emitRecord(
           S.Out, S.ScratchRecord, abbrCode,
           theAttr->isImplicit(),
           LIST_VER_TUPLE_PIECES(Version),
-          static_cast<unsigned>(theAttr->Platform));
+          static_cast<unsigned>(theAttr->getPlatform()));
       return;
     }
 
@@ -3194,52 +3214,39 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
       return;
     }
 
+    case DeclAttrKind::Specialized:
     case DeclAttrKind::Specialize: {
       auto abbrCode = S.DeclTypeAbbrCodes[SpecializeDeclAttrLayout::Code];
-      auto attr = cast<SpecializeAttr>(DA);
-      auto targetFun = attr->getTargetFunctionName();
+      auto attr = cast<AbstractSpecializeAttr>(DA);
       auto *afd = cast<AbstractFunctionDecl>(D);
       auto *targetFunDecl = attr->getTargetFunctionDecl(afd);
 
       SmallVector<IdentifierID, 4> pieces;
 
-      // encodes whether this a a simple or compound name by adding one.
-      size_t numArgs = 0;
-      if (targetFun) {
-        pieces.push_back(S.addDeclBaseNameRef(targetFun.getBaseName()));
-        for (auto argName : targetFun.getArgumentNames())
-          pieces.push_back(S.addDeclBaseNameRef(argName));
-        if (targetFun.isSimpleName()) {
-          assert(pieces.size() == 1);
-          numArgs = 1;
-        } else
-          numArgs = pieces.size() + 1;
-      }
-
+      // SPI groups
+      auto numSPIGroups = attr->getSPIGroups().size();
       for (auto spi : attr->getSPIGroups()) {
         assert(!spi.empty() && "Empty SPI name");
         pieces.push_back(S.addDeclBaseNameRef(spi));
       }
 
+      // Type-erased params
       for (auto ty : attr->getTypeErasedParams()) {
         pieces.push_back(S.addTypeRef(ty));
       }
 
-      auto numSPIGroups = attr->getSPIGroups().size();
-      auto numTypeErasedParams = attr->getTypeErasedParams().size();
-      assert(pieces.size() == numArgs + numSPIGroups + numTypeErasedParams ||
-             pieces.size() == (numArgs - 1 + numSPIGroups + numTypeErasedParams));
       auto numAvailabilityAttrs = attr->getAvailableAttrs().size();
       SpecializeDeclAttrLayout::emitRecord(
-          S.Out, S.ScratchRecord, abbrCode, (unsigned)attr->isExported(),
+          S.Out, S.ScratchRecord, abbrCode, (unsigned)attr->isPublic(),
+          (unsigned)attr->isExported(),
           (unsigned)attr->getSpecializationKind(),
           S.addGenericSignatureRef(attr->getSpecializedSignature(afd)),
-          S.addDeclRef(targetFunDecl), numArgs, numSPIGroups,
-          numAvailabilityAttrs, numTypeErasedParams,
+          S.addDeclRef(targetFunDecl), numSPIGroups, numAvailabilityAttrs,
           pieces);
       for (auto availAttr : attr->getAvailableAttrs()) {
         writeDeclAttribute(D, availAttr);
       }
+      writeDeclNameRefIfNeeded(attr->getTargetFunctionName());
       return;
     }
 
@@ -3271,16 +3278,13 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
       auto abbrCode =
           S.DeclTypeAbbrCodes[DynamicReplacementDeclAttrLayout::Code];
       auto theAttr = cast<DynamicReplacementAttr>(DA);
-      auto replacedFun = theAttr->getReplacedFunctionName();
-      SmallVector<IdentifierID, 4> pieces;
-      pieces.push_back(S.addDeclBaseNameRef(replacedFun.getBaseName()));
-      for (auto argName : replacedFun.getArgumentNames())
-        pieces.push_back(S.addDeclBaseNameRef(argName));
+
       auto *afd = cast<ValueDecl>(D)->getDynamicallyReplacedDecl();
       assert(afd && "Missing replaced decl!");
       DynamicReplacementDeclAttrLayout::emitRecord(
           S.Out, S.ScratchRecord, abbrCode, false, /*implicit flag*/
-          S.addDeclRef(afd), pieces.size(), pieces);
+          S.addDeclRef(afd));
+      writeDeclNameRefIfNeeded(theAttr->getReplacedFunctionName());
       return;
     }
 
@@ -3353,8 +3357,7 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
              "`@derivative` attribute should have original declaration set "
              "during construction or parsing");
       auto origDeclNameRef = attr->getOriginalFunctionName();
-      auto origName = origDeclNameRef.Name.getBaseName();
-      IdentifierID origNameId = S.addDeclBaseNameRef(origName);
+
       DeclID origDeclID = S.addDeclRef(attr->getOriginalFunction(ctx));
       auto derivativeKind =
           getRawStableAutoDiffDerivativeFunctionKind(attr->getDerivativeKind());
@@ -3368,9 +3371,10 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
       for (unsigned i : range(parameterIndices->getCapacity()))
         paramIndicesVector.push_back(parameterIndices->contains(i));
       DerivativeDeclAttrLayout::emitRecord(
-          S.Out, S.ScratchRecord, abbrCode, attr->isImplicit(), origNameId,
+          S.Out, S.ScratchRecord, abbrCode, attr->isImplicit(),
           origAccessorKind.has_value(), rawAccessorKind, origDeclID,
           derivativeKind, paramIndicesVector);
+      writeDeclNameRefIfNeeded(origDeclNameRef.Name);
       return;
     }
 
@@ -3380,8 +3384,7 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
       assert(attr->getOriginalFunction() &&
              "`@transpose` attribute should have original declaration set "
              "during construction or parsing");
-      auto origName = attr->getOriginalFunctionName().Name.getBaseName();
-      IdentifierID origNameId = S.addDeclBaseNameRef(origName);
+
       DeclID origDeclID = S.addDeclRef(attr->getOriginalFunction());
       auto *parameterIndices = attr->getParameterIndices();
       assert(parameterIndices && "Parameter indices must be resolved");
@@ -3389,8 +3392,9 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
       for (unsigned i : range(parameterIndices->getCapacity()))
         paramIndicesVector.push_back(parameterIndices->contains(i));
       TransposeDeclAttrLayout::emitRecord(
-          S.Out, S.ScratchRecord, abbrCode, attr->isImplicit(), origNameId,
-          origDeclID, paramIndicesVector);
+          S.Out, S.ScratchRecord, abbrCode, attr->isImplicit(), origDeclID,
+          paramIndicesVector);
+      writeDeclNameRefIfNeeded(attr->getOriginalFunctionName().Name);
       return;
     }
 
@@ -3456,9 +3460,19 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
     case DeclAttrKind::Nonisolated: {
       auto *theAttr = cast<NonisolatedAttr>(DA);
       auto abbrCode = S.DeclTypeAbbrCodes[NonisolatedDeclAttrLayout::Code];
-      NonisolatedDeclAttrLayout::emitRecord(S.Out, S.ScratchRecord, abbrCode,
-                                            theAttr->isUnsafe(),
-                                            theAttr->isImplicit());
+      NonisolatedDeclAttrLayout::emitRecord(
+          S.Out, S.ScratchRecord, abbrCode,
+          static_cast<uint8_t>(theAttr->getModifier()), theAttr->isImplicit());
+      return;
+    }
+
+    case DeclAttrKind::InheritActorContext: {
+      auto *theAttr = cast<InheritActorContextAttr>(DA);
+      auto abbrCode =
+          S.DeclTypeAbbrCodes[InheritActorContextDeclAttrLayout::Code];
+      InheritActorContextDeclAttrLayout::emitRecord(
+          S.Out, S.ScratchRecord, abbrCode,
+          static_cast<uint8_t>(theAttr->getModifier()), theAttr->isImplicit());
       return;
     }
 
@@ -3545,6 +3559,13 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
     case DeclAttrKind::Lifetime: {
       return;
     }
+    case DeclAttrKind::Nonexhaustive: {
+      auto *theAttr = cast<NonexhaustiveAttr>(DA);
+      auto abbrCode = S.DeclTypeAbbrCodes[NonexhaustiveDeclAttrLayout::Code];
+      NonexhaustiveDeclAttrLayout::emitRecord(S.Out, S.ScratchRecord, abbrCode,
+                                              (unsigned)theAttr->getMode());
+      return;
+    }
     }
   }
 
@@ -3614,6 +3635,32 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
     }
   }
 
+  void writeDeclNameRefIfNeeded(DeclNameRef name) {
+    using namespace decls_block;
+
+    // DeclNameRefs are always optional and write nothing when absent.
+    if (!name)
+      return;
+
+    bool isCompoundName = name.isCompoundName();
+    bool hasModuleSelector = name.hasModuleSelector();
+    SmallVector<IdentifierID, 8> rawPieceIDs;
+
+    if (hasModuleSelector)
+      rawPieceIDs.push_back(S.addDeclBaseNameRef(name.getModuleSelector()));
+
+    rawPieceIDs.push_back(S.addDeclBaseNameRef(name.getBaseName()));
+
+    if (isCompoundName)
+      for (auto argName : name.getArgumentNames())
+        rawPieceIDs.push_back(S.addDeclBaseNameRef(argName));
+
+    auto abbrCode = S.DeclTypeAbbrCodes[DeclNameRefLayout::Code];
+    DeclNameRefLayout::emitRecord(S.Out, S.ScratchRecord, abbrCode,
+                                  isCompoundName, hasModuleSelector,
+                                  rawPieceIDs);
+  }
+  
   size_t addConformances(const IterableDeclContext *declContext,
                          ConformanceLookupKind lookupKind,
                          SmallVectorImpl<uint64_t> &data) {
@@ -4115,8 +4162,8 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
 
   void noteUseOfExportedPrespecialization(const AbstractFunctionDecl *afd) {
     bool hasNoted = false;
-    for (auto *A : afd->getAttrs().getAttributes<SpecializeAttr>()) {
-      auto *SA = cast<SpecializeAttr>(A);
+    for (auto *A : afd->getAttrs().getAttributes<AbstractSpecializeAttr>()) {
+      auto *SA = cast<AbstractSpecializeAttr>(A);
       if (!SA->isExported())
         continue;
       if (SA->getTargetFunctionDecl(afd)) {
@@ -4739,6 +4786,8 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
         param->isCompileTimeLiteral(),
         param->isConstVal(),
         param->isSending(),
+        param->isCallerIsolated(),
+        param->isAddressable(),
         getRawStableDefaultArgumentKind(argKind),
         S.addTypeRef(defaultExprType),
         getRawStableActorIsolationKind(isolation.getKind()),
@@ -4868,12 +4917,18 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
 
         unsigned condAbbrCode =
             S.DeclTypeAbbrCodes[ConditionalSubstitutionConditionLayout::Code];
-        for (const auto &condition : subs->getAvailability()) {
-          ENCODE_VER_TUPLE(osVersion, std::optional<llvm::VersionTuple>(
-                                          condition.first.getLowerEndpoint()));
+        for (const auto &query : subs->getAvailabilityQueries()) {
+          // FIXME: [availability] Support arbitrary domains (rdar://156513787).
+          DEBUG_ASSERT(query.getDomain().isPlatform());
+
+          auto availableRange = query.getPrimaryRange().value_or(
+              AvailabilityRange::alwaysAvailable());
+
+          ENCODE_VER_TUPLE(osVersion,
+                           std::optional<llvm::VersionTuple>(
+                               availableRange.getRawMinimumVersion()));
           ConditionalSubstitutionConditionLayout::emitRecord(
-              S.Out, S.ScratchRecord, condAbbrCode,
-              /*isUnavailable=*/condition.second,
+              S.Out, S.ScratchRecord, condAbbrCode, query.isUnavailability(),
               LIST_VER_TUPLE_PIECES(osVersion));
         }
       }
@@ -4991,6 +5046,14 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
                                   nameComponentsAndDependencies);
     if (auto *PL = elem->getParameterList())
       writeParameterList(PL);
+
+    auto fnType = ty->getAs<AnyFunctionType>();
+    if (fnType) {
+      auto lifetimeDependencies = fnType->getLifetimeDependencies();
+      if (!lifetimeDependencies.empty()) {
+        S.writeLifetimeDependencies(lifetimeDependencies);
+      }
+    }
   }
 
   void visitSubscriptDecl(const SubscriptDecl *subscript) {
@@ -5181,9 +5244,6 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
         case BuiltinMacroKind::IsolationMacro:
           builtinID = 2;
           break;
-        case BuiltinMacroKind::SwiftSettingsMacro:
-          builtinID = 3;
-          break;
         }
         break;
       }
@@ -5250,6 +5310,10 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
     llvm_unreachable("import decls should not be serialized");
   }
 
+  void visitUsingDecl(const UsingDecl *) {
+    llvm_unreachable("using decls should not be serialized");
+  }
+
   void visitEnumCaseDecl(const EnumCaseDecl *) {
     llvm_unreachable("enum case decls should not be serialized");
   }
@@ -5314,8 +5378,7 @@ void Serializer::writeASTBlockEntity(const Decl *D) {
   SWIFT_DEFER {
     // This is important enough to leave on in Release builds.
     if (initialOffset == Out.GetCurrentBitNo()) {
-      llvm::PrettyStackTraceString message("failed to serialize anything");
-      abort();
+      ABORT("failed to serialize anything");
     }
   };
 
@@ -5461,6 +5524,8 @@ static uint8_t getRawStableResultConvention(swift::ResultConvention rc) {
   SIMPLE_CASE(ResultConvention, UnownedInnerPointer)
   SIMPLE_CASE(ResultConvention, Autoreleased)
   SIMPLE_CASE(ResultConvention, Pack)
+  SIMPLE_CASE(ResultConvention, GuaranteedAddress)
+  SIMPLE_CASE(ResultConvention, Guaranteed)
   }
   llvm_unreachable("bad result convention kind");
 }
@@ -5508,6 +5573,31 @@ static TypeAliasDecl *findTypeAliasForBuiltin(ASTContext &Ctx, Type T) {
   return cast<TypeAliasDecl>(CurModuleResults[0]);
 }
 
+namespace {
+struct ImplementationOnlyWalker : TypeWalker {
+  bool hadImplementationOnlyDecl = false;
+  const ModuleDecl *currentModule;
+  ImplementationOnlyWalker(const ModuleDecl *M) : currentModule(M) {}
+  Action walkToTypePre(Type ty) override {
+    if (auto *typeAlias = dyn_cast<TypeAliasType>(ty)) {
+      if (importedImplementationOnly(typeAlias->getDecl()))
+        return Action::Stop;
+    } else if (auto *nominal = ty->getAs<NominalType>()) {
+      if (importedImplementationOnly(nominal->getDecl()))
+        return Action::Stop;
+    }
+    return Action::Continue;
+  }
+  bool importedImplementationOnly(const Decl *D) {
+    if (currentModule->isImportedImplementationOnly(D->getModuleContext())) {
+      hadImplementationOnlyDecl = true;
+      return true;
+    }
+    return false;
+  }
+};
+} // namespace
+
 class Serializer::TypeSerializer : public TypeVisitor<TypeSerializer> {
   Serializer &S;
 
@@ -5528,17 +5618,6 @@ class Serializer::TypeSerializer : public TypeVisitor<TypeSerializer> {
     llvm_unreachable("should not serialize an ErrorType");
   }
 
-  void visitUnresolvedType(const UnresolvedType *) {
-    // If for some reason we have an unresolved type while compiling with
-    // errors, just serialize an ErrorType and continue.
-    if (S.getASTContext().LangOpts.AllowModuleWithCompilerErrors) {
-      visitErrorType(
-          cast<ErrorType>(ErrorType::get(S.getASTContext()).getPointer()));
-      return;
-    }
-    llvm_unreachable("should not serialize an UnresolvedType");
-  }
-
   void visitPlaceholderType(const PlaceholderType *) {
     // If for some reason we have a placeholder type while compiling with
     // errors, just serialize an ErrorType and continue.
@@ -5570,8 +5649,8 @@ class Serializer::TypeSerializer : public TypeVisitor<TypeSerializer> {
     llvm_unreachable("error union types do not persist in the AST");
   }
 
-  void visitLocatableType(const LocatableType *) {
-    llvm_unreachable("locatable types do not persist in the AST");
+  void visitLocatableType(const LocatableType *LT) {
+    visit(LT->getSinglyDesugaredType());
   }
 
   void visitBuiltinTypeImpl(Type ty) {
@@ -5805,6 +5884,7 @@ class Serializer::TypeSerializer : public TypeVisitor<TypeSerializer> {
                                            paramKind,
                                            hasDecl,
                                            genericParam->getDepth(),
+                                           genericParam->getWeight(),
                                            genericParam->getIndex(),
                                            declOrIdentifier,
                                            valueTypeID);
@@ -5843,8 +5923,8 @@ class Serializer::TypeSerializer : public TypeVisitor<TypeSerializer> {
     switch (isolation.getKind()) {
     case swift::FunctionTypeIsolation::Kind::NonIsolated:
       return unsigned(FunctionTypeIsolation::NonIsolated);
-    case swift::FunctionTypeIsolation::Kind::NonIsolatedCaller:
-      return unsigned(FunctionTypeIsolation::NonIsolatedCaller);
+    case swift::FunctionTypeIsolation::Kind::NonIsolatedNonsending:
+      return unsigned(FunctionTypeIsolation::NonIsolatedNonsending);
     case swift::FunctionTypeIsolation::Kind::Parameter:
       return unsigned(FunctionTypeIsolation::Parameter);
     case swift::FunctionTypeIsolation::Kind::Erased:
@@ -5860,10 +5940,23 @@ class Serializer::TypeSerializer : public TypeVisitor<TypeSerializer> {
     using namespace decls_block;
 
     auto resultType = S.addTypeRef(fnTy->getResult());
-    auto clangType =
-      S.getASTContext().LangOpts.UseClangFunctionTypes
-      ? S.addClangTypeRef(fnTy->getClangTypeInfo().getType())
-      : ClangTypeID(0);
+    bool shouldSerializeClangType = true;
+    if (S.hadImplementationOnlyImport && S.M &&
+        S.M->getResilienceStrategy() != ResilienceStrategy::Resilient) {
+      // Deserializing clang types from implementation only modules could crash
+      // as the transitive clang module might not be available to retrieve the
+      // declarations from. In an optimal world we would make the deseriaization
+      // more resilient to these problems but the failure is in Clang's
+      // deserialization code path that is not architected with potentially
+      // missing declarations in mind.
+      ImplementationOnlyWalker walker{S.M};
+      Type(const_cast<FunctionType *>(fnTy)).walk(walker);
+      if (walker.hadImplementationOnlyDecl)
+        shouldSerializeClangType = false;
+    }
+    auto clangType = shouldSerializeClangType
+                         ? S.addClangTypeRef(fnTy->getClangTypeInfo().getType())
+                         : ClangTypeID(0);
 
     auto isolation = encodeIsolation(fnTy->getIsolation());
 
@@ -6141,8 +6234,7 @@ void Serializer::writeASTBlockEntity(Type ty) {
   SWIFT_DEFER {
     // This is important enough to leave on in Release builds.
     if (initialOffset == Out.GetCurrentBitNo()) {
-      llvm::PrettyStackTraceString message("failed to serialize anything");
-      abort();
+      ABORT("failed to serialize anything");
     }
   };
 
@@ -6257,6 +6349,9 @@ class ClangToSwiftBasicWriter :
   void writeTypeCoupledDeclRefInfo(clang::TypeCoupledDeclRefInfo info) {
     llvm_unreachable("TypeCoupledDeclRefInfo shouldn't be reached from swift");
   }
+  void writeHLSLSpirvOperand(clang::SpirvOperand) {
+    llvm_unreachable("SpirvOperand shouldn't be reached from swift");
+  }
 };
 
 }
@@ -6333,6 +6428,7 @@ void Serializer::writeAllDeclsAndTypes() {
   registerDeclTypeAbbr<ErrorFlagLayout>();
   registerDeclTypeAbbr<ErrorTypeLayout>();
   registerDeclTypeAbbr<ABIOnlyCounterpartLayout>();
+  registerDeclTypeAbbr<DeclNameRefLayout>();
 
   registerDeclTypeAbbr<ClangTypeLayout>();
 
@@ -6945,8 +7041,13 @@ void Serializer::writeAST(ModuleOrSourceFile DC) {
     nextFile->getTopLevelDeclsWithAuxiliaryDecls(fileDecls);
 
     for (auto D : fileDecls) {
-      if (isa<ImportDecl>(D) || isa<MacroExpansionDecl>(D) ||
-          isa<TopLevelCodeDecl>(D)) {
+      if (const auto *ID = dyn_cast<ImportDecl>(D)) {
+        if (ID->getAttrs().hasAttribute<ImplementationOnlyAttr>())
+          hadImplementationOnlyImport = true;
+        continue;
+      }
+      if (isa<MacroExpansionDecl>(D) || isa<TopLevelCodeDecl>(D) ||
+          isa<UsingDecl>(D)) {
         continue;
       }
 
diff --git a/lib/Serialization/Serialization.h b/lib/Serialization/Serialization.h
index df68ffb3c8f51..7e3d3f3102388 100644
--- a/lib/Serialization/Serialization.h
+++ b/lib/Serialization/Serialization.h
@@ -116,6 +116,8 @@ class Serializer : public SerializerBase {
   /// an error in the AST.
   bool hadError = false;
 
+  bool hadImplementationOnlyImport = false;
+
   /// Helper for serializing entities in the AST block object graph.
   ///
   /// Keeps track of assigning IDs to newly-seen entities, and collecting
diff --git a/lib/Serialization/SerializeDoc.cpp b/lib/Serialization/SerializeDoc.cpp
index 5c929484d45a1..2db485a9b1cae 100644
--- a/lib/Serialization/SerializeDoc.cpp
+++ b/lib/Serialization/SerializeDoc.cpp
@@ -743,7 +743,7 @@ static void emitBasicLocsRecord(llvm::BitstreamWriter &Out,
   if (auto *SF = MSF.dyn_cast<SourceFile*>()) {
     SF->walk(Writer);
   } else {
-    MSF.get<ModuleDecl*>()->walk(Writer);
+    cast<ModuleDecl *>(MSF)->walk(Writer);
   }
 
   SmallVector<uint64_t, 8> scratch;
@@ -809,7 +809,7 @@ static void emitFileListRecord(llvm::BitstreamWriter &Out,
   if (SourceFile *SF = MSF.dyn_cast<SourceFile *>()) {
     writer.emitSourceFileInfo(BasicSourceFileInfo(SF));
   } else {
-    auto *M = MSF.get<ModuleDecl *>();
+    auto *M = cast<ModuleDecl *>(MSF);
     M->collectBasicSourceFileInfo([&](const BasicSourceFileInfo &info) {
       writer.emitSourceFileInfo(info);
     });
diff --git a/lib/Serialization/SerializeSIL.cpp b/lib/Serialization/SerializeSIL.cpp
index 5bb428b7063ff..e496b30e2da8b 100644
--- a/lib/Serialization/SerializeSIL.cpp
+++ b/lib/Serialization/SerializeSIL.cpp
@@ -529,8 +529,16 @@ void SILSerializer::writeSILFunction(const SILFunction &F, bool DeclOnly) {
 
   unsigned numAttrs = NoBody ? 0 : F.getSpecializeAttrs().size();
   auto resilience = F.getModule().getSwiftModule()->getResilienceStrategy();
-  bool serializeDerivedEffects = (resilience != ResilienceStrategy::Resilient) &&
-                                 !F.hasSemanticsAttr("optimize.no.crossmodule");
+  bool serializeDerivedEffects =
+    // We must not serialize computed effects if library evolution is turned on,
+    // because the copy of the function, which is emitted into the current module,
+    // might have different effects in different versions of the library.
+    (resilience != ResilienceStrategy::Resilient ||
+    // But we can serialize computed effects for @alwaysEmitIntoClient functions,
+    // even when library evolution is enabled, because no copy of the function is
+    // emitted in the original module.
+    F.getLinkage() == SILLinkage::PublicNonABI) &&
+    !F.hasSemanticsAttr("optimize.no.crossmodule");
 
   F.visitArgEffects(
     [&](int effectIdx, int argumentIndex, bool isDerived) {
@@ -553,8 +561,8 @@ void SILSerializer::writeSILFunction(const SILFunction &F, bool DeclOnly) {
       (unsigned)F.getSpecialPurpose(), (unsigned)F.getInlineStrategy(),
       (unsigned)F.getOptimizationMode(), (unsigned)F.getPerfConstraints(),
       (unsigned)F.getClassSubclassScope(), (unsigned)F.hasCReferences(),
-      (unsigned)F.getEffectsKind(), (unsigned)numAttrs,
-      (unsigned)F.hasOwnership(), F.isAlwaysWeakImported(),
+      (unsigned)F.markedAsUsed(), (unsigned)F.getEffectsKind(),
+      (unsigned)numAttrs, (unsigned)F.hasOwnership(), F.isAlwaysWeakImported(),
       LIST_VER_TUPLE_PIECES(available), (unsigned)F.isDynamicallyReplaceable(),
       (unsigned)F.isExactSelfClass(), (unsigned)F.isDistributed(),
       (unsigned)F.isRuntimeAccessible(),
@@ -1706,6 +1714,7 @@ void SILSerializer::writeSILInstruction(const SILInstruction &SI) {
   case SILInstructionKind::IsUniqueInst:
   case SILInstructionKind::BeginCOWMutationInst:
   case SILInstructionKind::EndCOWMutationInst:
+  case SILInstructionKind::EndCOWMutationAddrInst:
   case SILInstructionKind::EndInitLetRefInst:
   case SILInstructionKind::HopToExecutorInst:
   case SILInstructionKind::ExtractExecutorInst:
@@ -2168,6 +2177,7 @@ void SILSerializer::writeSILInstruction(const SILInstruction &SI) {
   case SILInstructionKind::UncheckedTrivialBitCastInst:
   case SILInstructionKind::UncheckedBitwiseCastInst:
   case SILInstructionKind::UncheckedValueCastInst:
+  case SILInstructionKind::VectorBaseAddrInst:
   case SILInstructionKind::BridgeObjectToRefInst:
   case SILInstructionKind::BridgeObjectToWordInst:
   case SILInstructionKind::UpcastInst:
@@ -2226,9 +2236,7 @@ void SILSerializer::writeSILInstruction(const SILInstruction &SI) {
   // Checked Conversion instructions.
   case SILInstructionKind::UnconditionalCheckedCastInst: {
     auto CI = cast<UnconditionalCheckedCastInst>(&SI);
-    unsigned flags = 0;
-    if (CI->getIsolatedConformances() == CastingIsolatedConformances::Prohibit)
-      flags |= 0x01;
+    unsigned flags = CI->getCheckedCastOptions().getStorage();
     ValueID listOfValues[] = {
       addValueRef(CI->getOperand()),
       S.addTypeRef(CI->getSourceLoweredType().getRawASTType()),
@@ -2247,9 +2255,7 @@ void SILSerializer::writeSILInstruction(const SILInstruction &SI) {
   }
   case SILInstructionKind::UnconditionalCheckedCastAddrInst: {
     auto CI = cast<UnconditionalCheckedCastAddrInst>(&SI);
-    unsigned flags = 0;
-    if (CI->getIsolatedConformances() == CastingIsolatedConformances::Prohibit)
-      flags |= 0x01;
+    unsigned flags = CI->getCheckedCastOptions().getStorage();
     ValueID listOfValues[] = {
       S.addTypeRef(CI->getSourceFormalType()),
       addValueRef(CI->getSrc()),
@@ -2442,7 +2448,6 @@ void SILSerializer::writeSILInstruction(const SILInstruction &SI) {
                   addValueRef(operand));
     break;
   }
-  case SILInstructionKind::AssignByWrapperInst:
   case SILInstructionKind::AssignOrInitInst:
     llvm_unreachable("not supported");
   case SILInstructionKind::BindMemoryInst: {
@@ -2770,8 +2775,7 @@ void SILSerializer::writeSILInstruction(const SILInstruction &SI) {
     unsigned flags = 0;
     if (CBI->isExact())
       flags |= 0x01;
-    if (CBI->getIsolatedConformances() == CastingIsolatedConformances::Prohibit)
-      flags |= 0x02;
+    flags |= (CBI->getCheckedCastOptions().getStorage() << 1);
     ValueID listOfValues[] = {
       flags,
       S.addTypeRef(CBI->getSourceFormalType()),
@@ -2795,9 +2799,8 @@ void SILSerializer::writeSILInstruction(const SILInstruction &SI) {
   case SILInstructionKind::CheckedCastAddrBranchInst: {
     auto CBI = cast<CheckedCastAddrBranchInst>(&SI);
     unsigned flags =
-      toStableCastConsumptionKind(CBI->getConsumptionKind()) << 1;
-    if (CBI->getIsolatedConformances() == CastingIsolatedConformances::Prohibit)
-      flags |= 0x01;
+      toStableCastConsumptionKind(CBI->getConsumptionKind()) << 8;
+    flags |= CBI->getCheckedCastOptions().getStorage();
     ValueID listOfValues[] = {
       flags,
       S.addTypeRef(CBI->getSourceFormalType()),
@@ -3111,13 +3114,19 @@ void SILSerializer::writeSILGlobalVar(const SILGlobalVariable &g) {
   GlobalVarOffset.push_back(Out.GetCurrentBitNo());
   TypeID TyID = S.addTypeRef(g.getLoweredType().getRawASTType());
   DeclID dID = S.addDeclRef(g.getDecl());
+
+  ModuleID parentModuleID;
+  if (auto *parentModule = g.getParentModule())
+    parentModuleID = S.addModuleRef(parentModule);
+
   SILGlobalVarLayout::emitRecord(Out, ScratchRecord,
                                  SILAbbrCodes[SILGlobalVarLayout::Code],
                                  toStableSILLinkage(g.getLinkage()),
                                  (unsigned)g.getSerializedKind(),
                                  (unsigned)!g.isDefinition(),
                                  (unsigned)g.isLet(),
-                                 TyID, dID);
+                                 (unsigned)g.markedAsUsed(),
+                                 TyID, dID, parentModuleID);
 
   // Don't emit the initializer instructions if not marked as "serialized".
   if (!g.isAnySerialized())
@@ -3306,13 +3315,13 @@ void SILSerializer::writeDebugScopes(const SILDebugScope *Scope,
 
   // A debug scope's parent can either be a function or a debug scope.
   // Handle both cases appropriately.
-  if (Scope->Parent.is<const SILDebugScope *>()) {
-    auto Parent = Scope->Parent.get<const SILDebugScope *>();
+  if (isa<const SILDebugScope *>(Scope->Parent)) {
+    auto Parent = cast<const SILDebugScope *>(Scope->Parent);
     if (DebugScopeMap.find(Parent) == DebugScopeMap.end())
       writeDebugScopes(Parent, SM);
     ParentID = DebugScopeMap[Parent];
   } else {
-    const SILFunction *ParentFn = Scope->Parent.get<SILFunction *>();
+    const SILFunction *ParentFn = cast<SILFunction *>(Scope->Parent);
     assert(ParentFn);
     isFuncParent = true;
     FuncsToEmitDebug.insert(ParentFn);
@@ -3362,6 +3371,7 @@ void SILSerializer::writeSILWitnessTable(const SILWitnessTable &wt) {
     SILAbbrCodes[WitnessTableLayout::Code],
     toStableSILLinkage(wt.getLinkage()),
     unsigned(wt.isDeclaration()),
+    unsigned(wt.isSpecialized()),
     unsigned(wt.getSerializedKind()),
     conformanceID);
 
@@ -3374,12 +3384,11 @@ void SILSerializer::writeSILWitnessTable(const SILWitnessTable &wt) {
   }
 
   for (auto conditional : wt.getConditionalConformances()) {
-    auto requirementID = S.addTypeRef(conditional.Requirement);
-    auto conformanceID = S.addConformanceRef(conditional.Conformance);
+    auto conformanceID = S.addConformanceRef(conditional);
     WitnessConditionalConformanceLayout::emitRecord(
         Out, ScratchRecord,
         SILAbbrCodes[WitnessConditionalConformanceLayout::Code],
-        requirementID, conformanceID);
+        conformanceID);
   }
 }
 
@@ -3402,13 +3411,12 @@ void SILSerializer::writeSILWitnessTableEntry(
     auto &assoc = entry.getAssociatedConformanceWitness();
 
     auto requirementID = S.addTypeRef(assoc.Requirement);
-    auto substTypeID = S.addTypeRef(assoc.SubstType);
     auto conformanceID = S.addConformanceRef(assoc.Witness);
 
     WitnessAssocProtocolLayout::emitRecord(
       Out, ScratchRecord,
       SILAbbrCodes[WitnessAssocProtocolLayout::Code],
-      requirementID, substTypeID, conformanceID);
+      requirementID, conformanceID);
     return;
   }
 
@@ -3571,6 +3579,12 @@ bool SILSerializer::shouldEmitFunctionBody(const SILFunction *F,
   if (F->isAvailableExternally())
     return false;
 
+  if (F->getDeclRef().hasDecl()) {
+    if (auto decl = F->getDeclRef().getDecl())
+      if (decl->isNeverEmittedIntoClient())
+        return false;
+  }
+
   // If we are asked to serialize everything, go ahead and do it.
   if (ShouldSerializeAll)
     return true;
diff --git a/lib/Serialization/SerializedModuleLoader.cpp b/lib/Serialization/SerializedModuleLoader.cpp
index c0d81d8d45b79..bcedbc8d0471e 100644
--- a/lib/Serialization/SerializedModuleLoader.cpp
+++ b/lib/Serialization/SerializedModuleLoader.cpp
@@ -108,14 +108,11 @@ std::optional<bool> forEachModuleSearchPath(
             callback(path.Path, ModuleSearchPathKind::Framework, path.IsSystem))
       return result;
 
-  // Apple platforms have extra implicit framework search paths:
-  // $SDKROOT/System/Library/Frameworks/ and $SDKROOT/Library/Frameworks/.
-  if (Ctx.LangOpts.Target.isOSDarwin()) {
-    for (const auto &path : Ctx.getDarwinImplicitFrameworkSearchPaths())
-      if (auto result =
-              callback(path, ModuleSearchPathKind::DarwinImplicitFramework,
-                       /*isSystem=*/true))
-        return result;
+  for (const auto &path :
+       Ctx.SearchPathOpts.getImplicitFrameworkSearchPaths()) {
+    if (auto result = callback(path, ModuleSearchPathKind::ImplicitFramework,
+                               /*isSystem=*/true))
+      return result;
   }
 
   for (const auto &importPath :
@@ -240,7 +237,7 @@ void SerializedModuleLoaderBase::collectVisibleTopLevelModuleNamesImpl(
       return std::nullopt;
     }
     case ModuleSearchPathKind::Framework:
-    case ModuleSearchPathKind::DarwinImplicitFramework: {
+    case ModuleSearchPathKind::ImplicitFramework: {
       // Look for:
       // $PATH/{name}.framework/Modules/{name}.swiftmodule/{arch}.{extension}
       forEachDirectoryEntryPath(searchPath, [&](StringRef path) {
@@ -316,8 +313,6 @@ std::optional<std::string> SerializedModuleLoaderBase::invalidModuleReason(seria
     return "compiled with a different version of the compiler";
   case Status::ChannelIncompatible:
     return "compiled for a different distribution channel";
-  case Status::NotInOSSA:
-    return "module was not built with OSSA";
   case Status::MissingDependency:
     return "missing dependency";
   case Status::MissingUnderlyingModule:
@@ -346,9 +341,9 @@ std::optional<std::string> SerializedModuleLoaderBase::invalidModuleReason(seria
 
 llvm::ErrorOr<std::vector<ScannerImportStatementInfo>>
 SerializedModuleLoaderBase::getMatchingPackageOnlyImportsOfModule(
-    Twine modulePath, bool isFramework, bool isRequiredOSSAModules,
-    StringRef SDKName, StringRef packageName, llvm::vfs::FileSystem *fileSystem,
-    PathObfuscator &recoverer) {
+    Twine modulePath, bool isFramework,
+    StringRef SDKName, const llvm::Triple &target, StringRef packageName,
+    llvm::vfs::FileSystem *fileSystem, PathObfuscator &recoverer) {
   auto moduleBuf = fileSystem->getBufferForFile(modulePath);
   if (!moduleBuf)
     return moduleBuf.getError();
@@ -358,7 +353,7 @@ SerializedModuleLoaderBase::getMatchingPackageOnlyImportsOfModule(
   std::shared_ptr<const ModuleFileSharedCore> loadedModuleFile;
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       "", "", std::move(moduleBuf.get()), nullptr, nullptr, isFramework,
-      isRequiredOSSAModules, SDKName, recoverer, loadedModuleFile);
+      SDKName, target, recoverer, loadedModuleFile);
 
   if (loadedModuleFile->getModulePackageName() != packageName)
     return importedModuleNames;
@@ -376,7 +371,8 @@ SerializedModuleLoaderBase::getMatchingPackageOnlyImportsOfModule(
     if (dotPos != std::string::npos)
       moduleName = moduleName.slice(0, dotPos);
 
-    importedModuleNames.push_back({moduleName.str(), dependency.isExported()});
+    importedModuleNames.push_back({moduleName.str(), dependency.isExported(),
+      dependency.isInternalOrBelow() ? AccessLevel::Internal : AccessLevel::Public});
   }
 
   return importedModuleNames;
@@ -481,8 +477,7 @@ SerializedModuleLoaderBase::getImportsOfModule(
     const ModuleFileSharedCore &loadedModuleFile,
     ModuleLoadingBehavior transitiveBehavior, StringRef packageName,
     bool isTestableImport) {
-  llvm::StringSet<> importedModuleNames;
-  llvm::StringSet<> importedExportedModuleNames;
+  std::vector<ScannerImportStatementInfo> moduleImports;
   std::string importedHeader = "";
   for (const auto &dependency : loadedModuleFile.getDependencies()) {
     if (dependency.isHeader()) {
@@ -516,13 +511,13 @@ SerializedModuleLoaderBase::getImportsOfModule(
     if (moduleName == Ctx.Id_CxxStdlib.str())
       moduleName = "std";
 
-    importedModuleNames.insert(moduleName);
-    if (dependency.isExported())
-      importedExportedModuleNames.insert(moduleName);
+    moduleImports.push_back(ScannerImportStatementInfo(
+        moduleName.str(), dependency.isExported(),
+        dependency.isInternalOrBelow() ? AccessLevel::Internal
+                                       : AccessLevel::Public));
   }
 
-  return SerializedModuleLoaderBase::BinaryModuleImports{importedModuleNames,
-                                                         importedExportedModuleNames,
+  return SerializedModuleLoaderBase::BinaryModuleImports{moduleImports,
                                                          importedHeader};
 }
 
@@ -546,120 +541,6 @@ SerializedModuleLoaderBase::resolveMacroPlugin(const ExternalMacroPlugin &macro,
                                entry.executablePath.str()};
 }
 
-llvm::ErrorOr<ModuleDependencyInfo>
-SerializedModuleLoaderBase::scanModuleFile(Twine modulePath, bool isFramework,
-                                           bool isTestableImport,
-                                           bool isCandidateForTextualModule) {
-  const std::string moduleDocPath;
-  const std::string sourceInfoPath;
-
-  // Read and valid module.
-  auto moduleBuf = Ctx.SourceMgr.getFileSystem()->getBufferForFile(modulePath);
-  if (!moduleBuf)
-    return moduleBuf.getError();
-
-  std::shared_ptr<const ModuleFileSharedCore> loadedModuleFile;
-  serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
-      "", "", std::move(moduleBuf.get()), nullptr, nullptr, isFramework,
-      isRequiredOSSAModules(), Ctx.LangOpts.SDKName,
-      Ctx.SearchPathOpts.DeserializedPathRecoverer, loadedModuleFile);
-
-  if (Ctx.SearchPathOpts.ScannerModuleValidation) {
-    // If failed to load, just ignore and return do not found.
-    if (auto loadFailureReason = invalidModuleReason(loadInfo.status)) {
-      // If no textual interface was found, then for this dependency
-      // scanning query this was *the* module discovered, which means
-      // it would be helpful to let the user know why the scanner
-      // was not able to use it because the scan will ultimately fail to
-      // resolve this dependency due to this incompatibility.
-      if (!isCandidateForTextualModule)
-        Ctx.Diags.diagnose(SourceLoc(), diag::dependency_scan_module_incompatible,
-                           modulePath.str(), loadFailureReason.value());
-
-      if (Ctx.LangOpts.EnableModuleLoadingRemarks)
-        Ctx.Diags.diagnose(SourceLoc(), diag::dependency_scan_skip_module_invalid,
-                           modulePath.str(), loadFailureReason.value());
-      return std::make_error_code(std::errc::no_such_file_or_directory);
-    }
-
-    if (isTestableImport && !loadedModuleFile->isTestable()) {
-      Ctx.Diags.diagnose(SourceLoc(), diag::skip_module_not_testable,
-                         modulePath.str());
-      return std::make_error_code(std::errc::no_such_file_or_directory);
-    }
-  }
-
-  // Some transitive dependencies of binary modules are not required to be
-  // imported during normal builds.
-  // TODO: This is worth revisiting for debugger purposes where
-  //       loading the module is optional, and implementation-only imports
-  //       from modules with testing enabled where the dependency is
-  //       optional.
-  auto binaryModuleImports =
-      getImportsOfModule(*loadedModuleFile, ModuleLoadingBehavior::Required,
-                         Ctx.LangOpts.PackageName, isTestableImport);
-
-  // Lookup optional imports of this module also
-  auto binaryModuleOptionalImports =
-      getImportsOfModule(*loadedModuleFile, ModuleLoadingBehavior::Optional,
-                         Ctx.LangOpts.PackageName, isTestableImport);
-
-  auto importedModuleSet = binaryModuleImports->moduleImports;
-  std::vector<ScannerImportStatementInfo> moduleImports;
-  moduleImports.reserve(importedModuleSet.size());
-  llvm::transform(importedModuleSet.keys(), std::back_inserter(moduleImports),
-                  [&binaryModuleImports](llvm::StringRef N) {
-                    return ScannerImportStatementInfo(
-                        N.str(),
-                        binaryModuleImports->exportedModules.contains(N));
-                  });
-
-  auto importedHeader = binaryModuleImports->headerImport;
-  auto &importedOptionalModuleSet = binaryModuleOptionalImports->moduleImports;
-  auto &importedExportedOptionalModuleSet =
-      binaryModuleOptionalImports->exportedModules;
-  std::vector<ScannerImportStatementInfo> optionalModuleImports;
-  for (const auto optionalImportedModule : importedOptionalModuleSet.keys())
-    if (!importedModuleSet.contains(optionalImportedModule))
-      optionalModuleImports.push_back(
-          {optionalImportedModule.str(),
-           importedExportedOptionalModuleSet.contains(optionalImportedModule)});
-
-  std::vector<LinkLibrary> linkLibraries;
-  {
-    linkLibraries.reserve(loadedModuleFile->getLinkLibraries().size());
-    llvm::copy(loadedModuleFile->getLinkLibraries(),
-               std::back_inserter(linkLibraries));
-    if (loadedModuleFile->isFramework())
-      linkLibraries.emplace_back(
-          loadedModuleFile->getName(), LibraryKind::Framework,
-                      loadedModuleFile->isStaticLibrary());
-  }
-
-  // Attempt to resolve the module's defining .swiftinterface path
-  std::string definingModulePath =
-       loadedModuleFile->resolveModuleDefiningFilePath(Ctx.SearchPathOpts.getSDKPath());
-
-  std::string userModuleVer = loadedModuleFile->getUserModuleVersion().getAsString();
-  // Map the set of dependencies over to the "module dependencies".
-  auto dependencies = ModuleDependencyInfo::forSwiftBinaryModule(
-      modulePath.str(), moduleDocPath, sourceInfoPath, moduleImports,
-      optionalModuleImports, linkLibraries, importedHeader,
-      definingModulePath, isFramework, loadedModuleFile->isStaticLibrary(),
-      /*module-cache-key*/ "", userModuleVer);
-
-  for (auto &macro : loadedModuleFile->getExternalMacros()) {
-    auto deps =
-        resolveMacroPlugin(macro, loadedModuleFile->getModulePackageName());
-    if (!deps)
-      continue;
-    dependencies.addMacroDependency(macro.ModuleName, deps->LibraryPath,
-                                    deps->ExecutablePath);
-  }
-
-  return std::move(dependencies);
-}
-
 std::error_code ImplicitSerializedModuleLoader::findModuleFilesInDirectory(
     ImportPath::Element ModuleID, const SerializedModuleBaseName &BaseName,
     SmallVectorImpl<char> *ModuleInterfacePath,
@@ -667,7 +548,7 @@ std::error_code ImplicitSerializedModuleLoader::findModuleFilesInDirectory(
     std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-    bool skipBuildingInterface, bool IsFramework, bool IsTestableDependencyLookup) {
+    bool IsCanImportLookup, bool IsFramework, bool IsTestableDependencyLookup) {
   if (LoadMode == ModuleLoadingMode::OnlyInterface ||
       Ctx.IgnoreAdjacentModules)
     return std::make_error_code(std::errc::not_supported);
@@ -694,46 +575,60 @@ std::error_code ImplicitSerializedModuleLoader::findModuleFilesInDirectory(
   return std::error_code();
 }
 
-bool ImplicitSerializedModuleLoader::maybeDiagnoseTargetMismatch(
-    SourceLoc sourceLocation, StringRef moduleName,
-    const SerializedModuleBaseName &absoluteBaseName) {
+void SerializedModuleLoaderBase::identifyArchitectureVariants(
+    ASTContext &Ctx, const SerializedModuleBaseName &absoluteBaseName,
+    std::vector<std::string> &incompatibleArchModules) {
   llvm::vfs::FileSystem &fs = *Ctx.SourceMgr.getFileSystem();
 
-  // Get the last component of the base name, which is the target-specific one.
-  auto target = llvm::sys::path::filename(absoluteBaseName.baseName);
-
   // Strip off the last component to get the .swiftmodule folder.
   auto dir = absoluteBaseName.baseName;
   llvm::sys::path::remove_filename(dir);
 
   std::error_code errorCode;
-  std::string foundArchs;
   for (llvm::vfs::directory_iterator directoryIterator =
            fs.dir_begin(dir, errorCode), endIterator;
        directoryIterator != endIterator;
        directoryIterator.increment(errorCode)) {
     if (errorCode)
-      return false;
+      continue;
     StringRef filePath = directoryIterator->path();
     StringRef extension = llvm::sys::path::extension(filePath);
     if (file_types::lookupTypeForExtension(extension) ==
           file_types::TY_SwiftModuleFile) {
-      if (!foundArchs.empty())
-        foundArchs += ", ";
-      foundArchs += llvm::sys::path::stem(filePath).str();
+      incompatibleArchModules.push_back(filePath.str());
     }
   }
+}
 
-  if (foundArchs.empty()) {
-    // Maybe this swiftmodule directory only contains swiftinterfaces, or
-    // maybe something else is going on. Regardless, we shouldn't emit a
-    // possibly incorrect diagnostic.
+bool ImplicitSerializedModuleLoader::handlePossibleTargetMismatch(
+    SourceLoc sourceLocation, StringRef moduleName,
+    const SerializedModuleBaseName &absoluteBaseName,
+    bool isCanImportLookup) {
+  std::string foundArchs;
+  std::vector<std::string> foundIncompatibleArchModules;
+  identifyArchitectureVariants(Ctx, absoluteBaseName,
+                               foundIncompatibleArchModules);
+
+  // Maybe this swiftmodule directory only contains swiftinterfaces, or
+  // maybe something else is going on. Regardless, we shouldn't emit a
+  // possibly incorrect diagnostic.
+  if (foundIncompatibleArchModules.empty())
     return false;
+
+  // Generate combined list of discovered architectures
+  // for the diagnostic
+  for (const auto &modulePath : foundIncompatibleArchModules) {
+    if (!foundArchs.empty())
+      foundArchs += ", ";
+    foundArchs += llvm::sys::path::stem(modulePath).str();
   }
 
-  Ctx.Diags.diagnose(sourceLocation, diag::sema_no_import_target, moduleName,
-                     target, foundArchs, dir);
-  return true;
+  Ctx.Diags
+      .diagnose(sourceLocation, diag::sema_no_import_target, moduleName,
+                llvm::sys::path::filename(absoluteBaseName.baseName),
+                foundArchs, absoluteBaseName.baseName)
+      .limitBehaviorIf(isCanImportLookup, DiagnosticBehavior::Warning);
+  return !isCanImportLookup;
 }
 
 SerializedModuleBaseName::SerializedModuleBaseName(
@@ -837,7 +732,7 @@ bool SerializedModuleLoaderBase::findModule(
     std::unique_ptr<llvm::MemoryBuffer> *moduleBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *moduleDocBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *moduleSourceInfoBuffer,
-    bool skipBuildingInterface, bool isTestableDependencyLookup,
+    bool isCanImportLookup, bool isTestableDependencyLookup,
     bool &isFramework, bool &isSystemModule) {
   // Find a module with an actual, physical name on disk, in case
   // -module-alias is used (otherwise same).
@@ -883,7 +778,7 @@ bool SerializedModuleLoaderBase::findModule(
       auto result = findModuleFilesInDirectory(
           moduleID, absoluteBaseName, moduleInterfacePath,
           moduleInterfaceSourcePath, moduleBuffer, moduleDocBuffer,
-          moduleSourceInfoBuffer, skipBuildingInterface, IsFramework,
+          moduleSourceInfoBuffer, isCanImportLookup, IsFramework,
           isTestableDependencyLookup);
       if (!result)
         return SearchResult::Found;
@@ -896,8 +791,8 @@ bool SerializedModuleLoaderBase::findModule(
     // We can only get here if all targetFileNamePairs failed with
     // 'std::errc::no_such_file_or_directory'.
     if (firstAbsoluteBaseName &&
-        maybeDiagnoseTargetMismatch(moduleID.Loc, moduleName,
-                                    *firstAbsoluteBaseName))
+        handlePossibleTargetMismatch(moduleID.Loc, moduleName,
+                                     *firstAbsoluteBaseName, isCanImportLookup))
       return SearchResult::Error;
 
     return SearchResult::NotFound;
@@ -955,7 +850,7 @@ bool SerializedModuleLoaderBase::findModule(
       auto result = findModuleFilesInDirectory(
           moduleID, absoluteBaseName, moduleInterfacePath,
           moduleInterfaceSourcePath, moduleBuffer, moduleDocBuffer,
-          moduleSourceInfoBuffer, skipBuildingInterface, isFramework,
+          moduleSourceInfoBuffer, isCanImportLookup, isFramework,
           isTestableDependencyLookup);
       if (!result)
         return true;
@@ -964,7 +859,7 @@ bool SerializedModuleLoaderBase::findModule(
       continue;
     }
     case ModuleSearchPathKind::Framework:
-    case ModuleSearchPathKind::DarwinImplicitFramework: {
+    case ModuleSearchPathKind::ImplicitFramework: {
       isFramework = true;
       llvm::sys::path::append(currPath, moduleName + ".framework");
 
@@ -1056,8 +951,7 @@ LoadedFile *SerializedModuleLoaderBase::loadAST(
       moduleInterfacePath, moduleInterfaceSourcePath,
       std::move(moduleInputBuffer), std::move(moduleDocInputBuffer),
       std::move(moduleSourceInfoInputBuffer), isFramework,
-      isRequiredOSSAModules(),
-      Ctx.LangOpts.SDKName,
+      Ctx.LangOpts.SDKName, Ctx.LangOpts.Target,
       Ctx.SearchPathOpts.DeserializedPathRecoverer, loadedModuleFileCore);
   SerializedASTFile *fileUnit = nullptr;
 
@@ -1093,6 +987,8 @@ LoadedFile *SerializedModuleLoaderBase::loadAST(
       M.setIsConcurrencyChecked();
     if (loadedModuleFile->strictMemorySafety())
       M.setStrictMemorySafety();
+    if (loadedModuleFile->deferredCodeGen())
+      M.setDeferredCodeGen();
     if (loadedModuleFile->hasCxxInteroperability()) {
       M.setHasCxxInteroperability();
       M.setCXXStdlibKind(loadedModuleFile->getCXXStdlibKind());
@@ -1100,8 +996,6 @@ LoadedFile *SerializedModuleLoaderBase::loadAST(
     if (!loadedModuleFile->getModulePackageName().empty()) {
       M.setPackageName(Ctx.getIdentifier(loadedModuleFile->getModulePackageName()));
     }
-    if (loadedModuleFile->supportsExtensibleEnums())
-      M.setSupportsExtensibleEnums();
     M.setUserModuleVersion(loadedModuleFile->getUserModuleVersion());
     M.setSwiftInterfaceCompilerVersion(
         loadedModuleFile->getSwiftInterfaceCompilerVersion());
@@ -1216,10 +1110,6 @@ LoadedFile *SerializedModuleLoaderBase::loadAST(
   return fileUnit;
 }
 
-bool SerializedModuleLoaderBase::isRequiredOSSAModules() const {
-  return Ctx.SILOpts.EnableOSSAModules;
-}
-
 void swift::serialization::diagnoseSerializedASTLoadFailure(
     ASTContext &Ctx, SourceLoc diagLoc,
     const serialization::ValidationInfo &loadInfo,
@@ -1257,14 +1147,6 @@ void swift::serialization::diagnoseSerializedASTLoadFailure(
     Ctx.Diags.diagnose(diagLoc, diag::serialization_module_too_old, ModuleName,
                        moduleBufferID);
     break;
-  case serialization::Status::NotInOSSA:
-    if (Ctx.SerializationOpts.ExplicitModuleBuild ||
-        Ctx.SILOpts.EnableOSSAModules) {
-      Ctx.Diags.diagnose(diagLoc,
-                         diag::serialization_non_ossa_module_incompatible,
-                         ModuleName);
-    }
-    break;
   case serialization::Status::RevisionIncompatible:
     Ctx.Diags.diagnose(diagLoc, diag::serialization_module_incompatible_revision,
                        loadInfo.problematicRevision, ModuleName, moduleBufferID);
@@ -1359,7 +1241,6 @@ void swift::serialization::diagnoseSerializedASTLoadFailureTransitive(
   case serialization::Status::Valid:
   case serialization::Status::FormatTooNew:
   case serialization::Status::FormatTooOld:
-  case serialization::Status::NotInOSSA:
   case serialization::Status::RevisionIncompatible:
   case serialization::Status::ChannelIncompatible:
   case serialization::Status::Malformed:
@@ -1475,30 +1356,54 @@ static std::optional<StringRef> getFlagsFromInterfaceFile(StringRef &file,
 bool swift::extractCompilerFlagsFromInterface(
     StringRef interfacePath, StringRef buffer, llvm::StringSaver &ArgSaver,
     SmallVectorImpl<const char *> &SubArgs,
-    std::optional<llvm::Triple> PreferredTarget) {
+    std::optional<llvm::Triple> PreferredTarget, DiagnosticEngine *Diag) {
   auto FlagMatch = getFlagsFromInterfaceFile(buffer, SWIFT_MODULE_FLAGS_KEY);
   if (!FlagMatch)
     return true;
   llvm::cl::TokenizeGNUCommandLine(*FlagMatch, ArgSaver, SubArgs);
 
-  // If the target triple parsed from the Swift interface file differs
-  // only in subarchitecture from the compatible target triple, then
-  // we have loaded a Swift interface from a different-but-compatible
-  // architecture slice. Use the compatible subarchitecture.
-  if (PreferredTarget) {
-    for (unsigned I = 1; I < SubArgs.size(); ++I) {
-      if (strcmp(SubArgs[I - 1], "-target") != 0 &&
-          strcmp(SubArgs[I - 1], "-target-variant") != 0)
-        continue;
+  for (unsigned I = 1; I < SubArgs.size(); ++I) {
+    if (strcmp(SubArgs[I - 1], "-target") != 0 &&
+        strcmp(SubArgs[I - 1], "-target-variant") != 0)
+      continue;
 
-      llvm::Triple triple(SubArgs[I]);
-      if (triple.getArch() != PreferredTarget->getArch())
-        continue;
-      if (triple.getSubArch() == PreferredTarget->getSubArch())
-        continue;
+    llvm::Triple triple(SubArgs[I]);
+    bool shouldModify = false;
+    // If the target triple parsed from the swiftinterface file differs
+    // only in subarchitecture from the compatible target triple, then
+    // we have loaded a Swift interface from a different-but-compatible
+    // architecture slice. Use the compatible subarchitecture.
+    if (PreferredTarget && triple.getArch() == PreferredTarget->getArch() &&
+        triple.getSubArch() != PreferredTarget->getSubArch()) {
       triple.setArch(PreferredTarget->getArch(), PreferredTarget->getSubArch());
-      SubArgs[I] = ArgSaver.save(triple.str()).data();
+      shouldModify = true;
     }
+
+    // Canonicalize the version in the target triple parsed from the
+    // swiftinterface.
+    auto canonicalTriple = getCanonicalTriple(triple);
+    if (!canonicalTriple.has_value()) {
+      if (Diag) {
+        const llvm::VersionTuple OSVersion = triple.getOSVersion();
+        const bool isOSVersionInValidRange =
+            llvm::Triple::isValidVersionForOS(triple.getOS(), OSVersion);
+        const llvm::VersionTuple canonicalVersion =
+            llvm::Triple::getCanonicalVersionForOS(
+                triple.getOS(), triple.getOSVersion(), isOSVersionInValidRange);
+        Diag->diagnose(SourceLoc(),
+                       diag::map_os_version_from_textual_interface_failed,
+                       OSVersion.getAsString(), canonicalVersion.getAsString(),
+                       interfacePath);
+      }
+      break;
+    }
+    // Update the triple to use if it differs.
+    if (!areTriplesStrictlyEqual(triple, *canonicalTriple)) {
+      triple = *canonicalTriple;
+      shouldModify = true;
+    }
+    if (shouldModify)
+      SubArgs[I] = ArgSaver.save(triple.str()).data();
   }
 
   auto IgnFlagMatch =
@@ -1571,19 +1476,22 @@ swift::extractUserModuleVersionFromInterface(StringRef moduleInterfacePath) {
   return result;
 }
 
-std::string swift::extractEmbeddedBridgingHeaderContent(
-    std::unique_ptr<llvm::MemoryBuffer> file, ASTContext &Context) {
+std::unique_ptr<llvm::MemoryBuffer> swift::extractEmbeddedBridgingHeaderContent(
+    std::unique_ptr<llvm::MemoryBuffer> file, StringRef headerPath,
+    ASTContext &Context) {
   std::shared_ptr<const ModuleFileSharedCore> loadedModuleFile;
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       "", "", std::move(file), nullptr, nullptr, false,
-      Context.SILOpts.EnableOSSAModules, Context.LangOpts.SDKName,
+      Context.LangOpts.SDKName,
+      Context.LangOpts.Target,
       Context.SearchPathOpts.DeserializedPathRecoverer,
       loadedModuleFile);
 
   if (loadInfo.status != serialization::Status::Valid)
-    return {};
+    return nullptr;;
 
-  return loadedModuleFile->getEmbeddedHeader();
+  return llvm::MemoryBuffer::getMemBufferCopy(
+      loadedModuleFile->getEmbeddedHeader(), headerPath);
 }
 
 bool SerializedModuleLoaderBase::canImportModule(
@@ -1604,7 +1512,7 @@ bool SerializedModuleLoaderBase::canImportModule(
       mID, /*moduleInterfacePath=*/nullptr, &moduleInterfaceSourcePath,
       &moduleInputBuffer,
       /*moduleDocBuffer=*/nullptr, /*moduleSourceInfoBuffer=*/nullptr,
-      /*skipBuildingInterface=*/true, isTestableDependencyLookup,
+      /*isCanImportLookup=*/true, isTestableDependencyLookup,
       isFramework, isSystemModule);
   // If we cannot find the module, don't continue.
   if (!found)
@@ -1629,7 +1537,7 @@ bool SerializedModuleLoaderBase::canImportModule(
 
   if (moduleInputBuffer) {
     auto metaData = serialization::validateSerializedAST(
-        moduleInputBuffer->getBuffer(), Ctx.SILOpts.EnableOSSAModules,
+        moduleInputBuffer->getBuffer(),
         Ctx.LangOpts.SDKName);
 
     // If we only found binary module, make sure that is valid.
@@ -1699,7 +1607,7 @@ SerializedModuleLoaderBase::loadModule(SourceLoc importLoc,
   if (!findModule(moduleID, &moduleInterfacePath, &moduleInterfaceSourcePath,
                   &moduleInputBuffer, &moduleDocInputBuffer,
                   &moduleSourceInfoInputBuffer,
-                  /*skipBuildingInterface=*/false,
+                  /*isCanImportLookup=*/false,
                   /*isTestableDependencyLookup=*/false,
                   isFramework,
                   isSystemModule)) {
@@ -1839,7 +1747,7 @@ std::error_code MemoryBufferSerializedModuleLoader::findModuleFilesInDirectory(
     std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
     std::unique_ptr<llvm::MemoryBuffer> *ModuleSourceInfoBuffer,
-    bool skipBuildingInterface, bool IsFramework,
+    bool isCanImportLookup, bool IsFramework,
     bool isTestableDependencyLookup) {
   // This is a soft error instead of an llvm_unreachable because this API is
   // primarily used by LLDB which makes it more likely that unwitting changes to
@@ -1848,12 +1756,6 @@ std::error_code MemoryBufferSerializedModuleLoader::findModuleFilesInDirectory(
   return std::make_error_code(std::errc::not_supported);
 }
 
-bool MemoryBufferSerializedModuleLoader::maybeDiagnoseTargetMismatch(
-    SourceLoc sourceLocation, StringRef moduleName,
-    const SerializedModuleBaseName &absoluteBaseName) {
-  return false;
-}
-
 void SerializedModuleLoaderBase::verifyAllModules() {
 #ifndef NDEBUG
   for (const LoadedModulePair &loaded : LoadedModuleFiles)
@@ -2007,6 +1909,14 @@ void SerializedASTFile::lookupImportedSPIGroups(
   }
 }
 
+bool SerializedASTFile::isModuleImportedPreconcurrency(
+    const ModuleDecl *importedModule) const {
+  // This method should only be queried during `-merge-modules` jobs, which are
+  // deprecated, and thus no effort has been made to answer this query correctly
+  // (@preconcurrency is not encoded on imports in serialized modules).
+  return false;
+}
+
 std::optional<CommentInfo>
 SerializedASTFile::getCommentForDecl(const Decl *D) const {
   return File.getCommentForDecl(D);
diff --git a/lib/StaticMirror/ObjectFileContext.cpp b/lib/StaticMirror/ObjectFileContext.cpp
index 397321d8254c1..ed8239ebb183d 100644
--- a/lib/StaticMirror/ObjectFileContext.cpp
+++ b/lib/StaticMirror/ObjectFileContext.cpp
@@ -29,6 +29,7 @@
 #include "llvm/Object/ELFTypes.h"
 #include "llvm/Object/MachOUniversal.h"
 #include "llvm/Object/RelocationResolver.h"
+#include "llvm/Object/Wasm.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/StringSaver.h"
 
@@ -266,6 +267,38 @@ void Image::scanCOFF(const llvm::object::COFFObjectFile *O) {
   Segments.push_back({HeaderAddress, O->getData()});
 }
 
+void Image::scanWasm(const llvm::object::WasmObjectFile *O) {
+  HeaderAddress = 0;
+
+  auto resolver = getRelocationResolver(*O);
+  auto resolverSupports = resolver.first;
+  auto resolve = resolver.second;
+
+  if (!resolverSupports || !resolve)
+    return;
+
+  for (auto SectionRef : O->sections()) {
+    auto Section = O->getWasmSection(SectionRef);
+    for (auto &r : Section.Relocations) {
+      auto sym = O->symbol_begin();
+      for (unsigned i = 0; sym != O->symbol_end() && i < r.Index; ++i)
+        ++sym;
+      if (sym == O->symbol_end())
+        continue;
+      auto &wsym = O->getWasmSymbol(*sym);
+      if (!resolverSupports(r.Type)) {
+        llvm::errs() << "Unsupported +" << r.Offset << " " << wsym.Info.Name
+                     << " +" << r.Addend << "\n";
+        continue;
+      }
+      uint64_t offset = resolve(r.Type, r.Offset, 0, 0, r.Addend);
+      DynamicRelocations.insert({r.Offset, {wsym.Info.Name, offset}});
+    }
+  }
+
+  Segments.push_back({HeaderAddress, O->getData()});
+}
+
 bool Image::isMachOWithPtrAuth() const {
   auto macho = dyn_cast<llvm::object::MachOObjectFile>(O);
   if (!macho)
@@ -286,6 +319,8 @@ Image::Image(const llvm::object::ObjectFile *O) : O(O) {
     scanELF(elf);
   } else if (auto coff = dyn_cast<llvm::object::COFFObjectFile>(O)) {
     scanCOFF(coff);
+  } else if (auto wasm = dyn_cast<llvm::object::WasmObjectFile>(O)) {
+    scanWasm(wasm);
   } else {
     fputs("unsupported image format\n", stderr);
     abort();
@@ -321,10 +356,11 @@ Image::resolvePointer(uint64_t Addr, uint64_t pointerValue) const {
   // base address in the low 32 bits, and ptrauth discriminator info in the top
   // 32 bits.
   if (isMachOWithPtrAuth()) {
-    return remote::RemoteAbsolutePointer(
-        "", HeaderAddress + (pointerValue & 0xffffffffull));
+    return remote::RemoteAbsolutePointer(remote::RemoteAddress(
+        HeaderAddress + (pointerValue & 0xffffffffull), 0));
   } else {
-    return remote::RemoteAbsolutePointer("", pointerValue);
+    return remote::RemoteAbsolutePointer(remote::RemoteAddress(
+        pointerValue, reflection::RemoteAddress::DefaultAddressSpace));
   }
 }
 
@@ -332,8 +368,13 @@ remote::RemoteAbsolutePointer Image::getDynamicSymbol(uint64_t Addr) const {
   auto found = DynamicRelocations.find(Addr);
   if (found == DynamicRelocations.end())
     return nullptr;
-  return remote::RemoteAbsolutePointer(found->second.Symbol,
-                                       found->second.Offset);
+  if (!found->second.Symbol.empty())
+    return remote::RemoteAbsolutePointer(found->second.Symbol,
+                                         found->second.OffsetOrAddress,
+                                         remote::RemoteAddress());
+  return remote::RemoteAbsolutePointer(
+      remote::RemoteAddress(found->second.OffsetOrAddress,
+                            remote::RemoteAddress::DefaultAddressSpace));
 }
 
 std::pair<const Image *, uint64_t>
@@ -347,9 +388,8 @@ ObjectMemoryReader::decodeImageIndexAndAddress(uint64_t Addr) const {
   return {nullptr, 0};
 }
 
-uint64_t
-ObjectMemoryReader::encodeImageIndexAndAddress(const Image *image,
-                                               uint64_t imageAddr) const {
+remote::RemoteAddress ObjectMemoryReader::encodeImageIndexAndAddress(
+    const Image *image, remote::RemoteAddress imageAddr) const {
   auto entry = (const ImageEntry *)image;
   return imageAddr + entry->Slide;
 }
@@ -481,19 +521,21 @@ ObjectMemoryReader::getImageStartAddress(unsigned i) const {
   assert(i < Images.size());
 
   return reflection::RemoteAddress(encodeImageIndexAndAddress(
-      &Images[i].TheImage, Images[i].TheImage.getStartAddress()));
+      &Images[i].TheImage,
+      remote::RemoteAddress(Images[i].TheImage.getStartAddress(),
+                            reflection::RemoteAddress::DefaultAddressSpace)));
 }
 
 ReadBytesResult ObjectMemoryReader::readBytes(reflection::RemoteAddress Addr,
                                               uint64_t Size) {
-  auto addrValue = Addr.getAddressData();
+  auto addrValue = Addr.getRawAddress();
   auto resultBuffer = getContentsAtAddress(addrValue, Size);
   return ReadBytesResult(resultBuffer.data(), no_op_destructor);
 }
 
 bool ObjectMemoryReader::readString(reflection::RemoteAddress Addr,
                                     std::string &Dest) {
-  auto addrValue = Addr.getAddressData();
+  auto addrValue = Addr.getRawAddress();
   auto resultBuffer = getContentsAtAddress(addrValue, 1);
   if (resultBuffer.empty())
     return false;
@@ -514,7 +556,7 @@ bool ObjectMemoryReader::readString(reflection::RemoteAddress Addr,
 remote::RemoteAbsolutePointer
 ObjectMemoryReader::resolvePointer(reflection::RemoteAddress Addr,
                                    uint64_t pointerValue) {
-  auto addrValue = Addr.getAddressData();
+  auto addrValue = Addr.getRawAddress();
   const Image *image;
   uint64_t imageAddr;
   std::tie(image, imageAddr) = decodeImageIndexAndAddress(addrValue);
@@ -525,14 +567,13 @@ ObjectMemoryReader::resolvePointer(reflection::RemoteAddress Addr,
   auto resolved = image->resolvePointer(imageAddr, pointerValue);
   // Mix in the image index again to produce a remote address pointing into the
   // same image.
-  return remote::RemoteAbsolutePointer(
-      "", encodeImageIndexAndAddress(
-              image, resolved.getResolvedAddress().getAddressData()));
+  return remote::RemoteAbsolutePointer(remote::RemoteAddress(
+      encodeImageIndexAndAddress(image, resolved.getResolvedAddress())));
 }
 
 remote::RemoteAbsolutePointer
 ObjectMemoryReader::getDynamicSymbol(reflection::RemoteAddress Addr) {
-  auto addrValue = Addr.getAddressData();
+  auto addrValue = Addr.getRawAddress();
   const Image *image;
   uint64_t imageAddr;
   std::tie(image, imageAddr) = decodeImageIndexAndAddress(addrValue);
@@ -543,6 +584,31 @@ ObjectMemoryReader::getDynamicSymbol(reflection::RemoteAddress Addr) {
   return image->getDynamicSymbol(imageAddr);
 }
 
+uint64_t ObjectMemoryReader::getPtrauthMask() {
+  auto initializePtrauthMask = [&]() -> uint64_t {
+    uint8_t pointerSize = 0;
+    if (!queryDataLayout(DataLayoutQueryType::DLQ_GetPointerSize, nullptr,
+                         &pointerSize))
+      return ~0ull;
+
+    if (pointerSize == 4) {
+      uint32_t ptrauthMask32 = 0;
+      if (queryDataLayout(DataLayoutQueryType::DLQ_GetPtrAuthMask, nullptr,
+                          &ptrauthMask32))
+        return (uint64_t)ptrauthMask32;
+    } else if (pointerSize == 8) {
+      uint64_t ptrauthMask64 = 0;
+      if (queryDataLayout(DataLayoutQueryType::DLQ_GetPtrAuthMask, nullptr,
+                          &ptrauthMask64))
+        return ptrauthMask64;
+    }
+    return ~0ull;
+  };
+  if (!PtrauthMask)
+    PtrauthMask = initializePtrauthMask();
+  return PtrauthMask;
+}
+
 template <typename Runtime>
 std::unique_ptr<ReflectionContextHolder> makeReflectionContextForMetadataReader(
     std::shared_ptr<ObjectMemoryReader> reader, uint8_t pointerSize) {
@@ -564,16 +630,18 @@ std::unique_ptr<ReflectionContextHolder> makeReflectionContextForObjectFiles(
   const std::vector<const ObjectFile *> &objectFiles, bool ObjCInterop) {
   auto Reader = std::make_shared<ObjectMemoryReader>(objectFiles);
 
-  uint8_t pointerSize;
-  Reader->queryDataLayout(DataLayoutQueryType::DLQ_GetPointerSize, nullptr,
-                          &pointerSize);
+  auto pointerSize = Reader->getPointerSize();
+  if (!pointerSize) {
+    fputs("unable to get target pointer size\n", stderr);
+    abort();
+  }
 
-  switch (pointerSize) {
+  switch (pointerSize.value()) {
   case 4:
 #define MAKE_CONTEXT(INTEROP, PTRSIZE)                                         \
   makeReflectionContextForMetadataReader<                                      \
       External<INTEROP<RuntimeTarget<PTRSIZE>>>>(std::move(Reader),            \
-                                                 pointerSize)
+                                                 pointerSize.value())
 #if SWIFT_OBJC_INTEROP
     if (ObjCInterop)
       return MAKE_CONTEXT(WithObjCInterop, 4);
diff --git a/lib/SymbolGraphGen/AvailabilityMixin.cpp b/lib/SymbolGraphGen/AvailabilityMixin.cpp
index ece561a30ece6..f4a3775413875 100644
--- a/lib/SymbolGraphGen/AvailabilityMixin.cpp
+++ b/lib/SymbolGraphGen/AvailabilityMixin.cpp
@@ -25,7 +25,7 @@ StringRef getDomain(const SemanticAvailableAttr &AvAttr) {
   if (AvAttr.getDomain().isPackageDescription())
     return { "SwiftPM" };
 
-  if (AvAttr.getDomain().isSwiftLanguage())
+  if (AvAttr.getDomain().isSwiftLanguageMode())
     return { "Swift" };
 
   // Platform-specific availability.
@@ -54,6 +54,8 @@ StringRef getDomain(const SemanticAvailableAttr &AvAttr) {
       return { "watchOSAppExtension" };
     case swift::PlatformKind::visionOSApplicationExtension:
       return { "visionOSAppExtension" };
+    case swift::PlatformKind::FreeBSD:
+      return { "FreeBSD" };
     case swift::PlatformKind::OpenBSD:
       return { "OpenBSD" };
     case swift::PlatformKind::Windows:
diff --git a/lib/SymbolGraphGen/Symbol.cpp b/lib/SymbolGraphGen/Symbol.cpp
index 993c47bb8af54..10adbb6de68fc 100644
--- a/lib/SymbolGraphGen/Symbol.cpp
+++ b/lib/SymbolGraphGen/Symbol.cpp
@@ -697,6 +697,26 @@ void Symbol::serializeAvailabilityMixin(llvm::json::OStream &OS) const {
   llvm::StringMap<Availability> Availabilities;
   getInheritedAvailabilities(D, Availabilities);
 
+  // If we were asked to filter the availability platforms for the output graph,
+  // perform that filtering here.
+  if (Graph->Walker.Options.AvailabilityPlatforms) {
+    auto AvailabilityPlatforms =
+        Graph->Walker.Options.AvailabilityPlatforms.value();
+    if (Graph->Walker.Options.AvailabilityIsBlockList) {
+      for (const auto Availability : Availabilities.keys()) {
+        if (Availability != "*" && AvailabilityPlatforms.contains(Availability)) {
+          Availabilities.erase(Availability);
+        }
+      }
+    } else {
+      for (const auto Availability : Availabilities.keys()) {
+        if (Availability != "*" && !AvailabilityPlatforms.contains(Availability)) {
+          Availabilities.erase(Availability);
+        }
+      }
+    }
+  }
+
   if (Availabilities.empty()) {
     return;
   }
diff --git a/lib/SymbolGraphGen/SymbolGraph.cpp b/lib/SymbolGraphGen/SymbolGraph.cpp
index bc22d5296d6dc..8866920421a76 100644
--- a/lib/SymbolGraphGen/SymbolGraph.cpp
+++ b/lib/SymbolGraphGen/SymbolGraph.cpp
@@ -88,6 +88,7 @@ PrintOptions SymbolGraph::getDeclarationFragmentsPrintOptions() const {
   ExcludeAttrs.erase("TypeAttrKind::NoEscape");
   ExcludeAttrs.erase("TypeAttrKind::Escaping");
   ExcludeAttrs.erase("TypeAttrKind::Inout");
+  ExcludeAttrs.erase("TypeAttrKind::Sendable");
 
   // Don't allow the following decl attributes:
   // These can be large and are already included elsewhere in
@@ -650,21 +651,6 @@ void SymbolGraph::serialize(llvm::json::OStream &OS) {
       }
     });
 
-#ifndef NDEBUG
-    // FIXME (solver-based-verification-sorting): In assert builds sort the
-    // edges so we get consistent symbol graph output. This allows us to compare
-    // the string representation of the symbolgraph between the solver-based
-    // and AST-based result.
-    // This can be removed once the AST-based cursor info has been removed.
-    SmallVector<Edge> Edges(this->Edges.begin(), this->Edges.end());
-    std::sort(Edges.begin(), Edges.end(), [](const Edge &LHS, const Edge &RHS) {
-      SmallString<256> LHSTargetUSR, RHSTargetUSR;
-      LHS.Target.getUSR(LHSTargetUSR);
-      RHS.Target.getUSR(RHSTargetUSR);
-      return LHSTargetUSR < RHSTargetUSR;
-    });
-#endif
-
     OS.attributeArray("relationships", [&](){
       for (const auto &Relationship : Edges) {
         Relationship.serialize(OS);
diff --git a/lib/SymbolGraphGen/SymbolGraph.h b/lib/SymbolGraphGen/SymbolGraph.h
index 6e33785e9e901..7750ad798ee23 100644
--- a/lib/SymbolGraphGen/SymbolGraph.h
+++ b/lib/SymbolGraphGen/SymbolGraph.h
@@ -13,15 +13,14 @@
 #ifndef SWIFT_SYMBOLGRAPHGEN_SYMBOLGRAPH_H
 #define SWIFT_SYMBOLGRAPHGEN_SYMBOLGRAPH_H
 
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/Support/JSON.h"
-#include "llvm/Support/VersionTuple.h"
+#include "Edge.h"
+#include "Symbol.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Markup/Markup.h"
 #include "swift/SymbolGraphGen/SymbolGraphOptions.h"
-#include "Edge.h"
-#include "JSON.h"
-#include "Symbol.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/Support/JSON.h"
+#include "llvm/Support/VersionTuple.h"
 
 namespace swift {
 namespace symbolgraphgen {
@@ -67,12 +66,12 @@ struct SymbolGraph {
   /**
    The symbols in a module: the nodes in the graph.
    */
-  llvm::DenseSet<Symbol> Nodes;
+  llvm::SetVector<Symbol> Nodes;
 
   /**
    The relationships between symbols: the edges in the graph.
    */
-  llvm::DenseSet<Edge> Edges;
+  llvm::SetVector<Edge> Edges;
 
   /**
    True if this graph is for a single symbol, rather than an entire module.
diff --git a/lib/SymbolGraphGen/SymbolGraphASTWalker.cpp b/lib/SymbolGraphGen/SymbolGraphASTWalker.cpp
index cb09d846b80a7..09b5c9430c694 100644
--- a/lib/SymbolGraphGen/SymbolGraphASTWalker.cpp
+++ b/lib/SymbolGraphGen/SymbolGraphASTWalker.cpp
@@ -28,6 +28,21 @@ using namespace symbolgraphgen;
 
 namespace {
 
+/// Get the fully-qualified module name of the given `ModuleDecl` as a `std::string`.
+///
+/// For example, if `M` is a submodule of `ParentModule` named `SubModule`,
+/// this function would return `"ParentModule.SubModule"`.
+std::string getFullModuleName(const ModuleDecl *M) {
+  if (!M) return {};
+
+  std::string S;
+  llvm::raw_string_ostream OS(S);
+
+  M->getReverseFullModuleName().printForward(OS);
+
+  return S;
+}
+
 /// Compare the two \c ModuleDecl instances to see whether they are the same.
 ///
 /// This does a by-name comparison to consider a module's underlying Clang module to be equivalent
@@ -36,7 +51,7 @@ namespace {
 /// If the `isClangEqual` argument is set to `false`, the modules must also be from the same
 /// compiler, i.e. a Swift module and its underlying Clang module would be considered not equal.
 bool areModulesEqual(const ModuleDecl *lhs, const ModuleDecl *rhs, bool isClangEqual = true) {
-  if (lhs->getNameStr() != rhs->getNameStr())
+  if (getFullModuleName(lhs) != getFullModuleName(rhs))
     return false;
 
   if (!isClangEqual && (lhs->isNonSwiftModule() != rhs->isNonSwiftModule()))
@@ -293,7 +308,7 @@ bool SymbolGraphASTWalker::walkToDeclPre(Decl *D, CharSourceRange Range) {
 
       // We also might establish some synthesized members because we
       // extended an external type.
-      if (ExtendedNominal->getModuleContext() != &M) {
+      if (!areModulesEqual(ExtendedNominal->getModuleContext(), &M)) {
         ExtendedSG->recordConformanceSynthesizedMemberRelationships(Source);
       }
     }
@@ -326,10 +341,13 @@ bool SymbolGraphASTWalker::walkToDeclPre(Decl *D, CharSourceRange Range) {
   // symbol, regardless of which class it's actually appearing on. To prevent
   // multiple of these symbols colliding with each other, treat them as
   // synthesized symbols and use their parent type as the base type.
-  if (VD->isImplicit() && VD->hasClangNode() &&
-      VD->getClangNode().getAsDecl()) {
-    if (const auto *Parent =
-            dyn_cast_or_null<NominalTypeDecl>(VD->getDeclContext())) {
+  if (VD->isImplicit() && VD->getClangDecl()) {
+    const NominalTypeDecl *Parent = dyn_cast_or_null<NominalTypeDecl>(VD->getDeclContext());
+    if (!Parent) {
+      if (const auto *ParentExt = dyn_cast_or_null<ExtensionDecl>(VD->getDeclContext()))
+        Parent = ParentExt->getExtendedNominal();
+    }
+    if (Parent) {
       SG->recordNode(Symbol(SG, VD, Parent));
       return true;
     }
diff --git a/lib/Tooling/libSwiftScan/libSwiftScan.cpp b/lib/Tooling/libSwiftScan/libSwiftScan.cpp
index 18f1e625de670..aa02d80238b72 100644
--- a/lib/Tooling/libSwiftScan/libSwiftScan.cpp
+++ b/lib/Tooling/libSwiftScan/libSwiftScan.cpp
@@ -35,9 +35,9 @@ void swiftscan_macro_dependency_dispose(
     return;
 
   for (unsigned i = 0; i < macro->count; ++i) {
-    swiftscan_string_dispose(macro->macro_dependencies[i]->moduleName);
-    swiftscan_string_dispose(macro->macro_dependencies[i]->libraryPath);
-    swiftscan_string_dispose(macro->macro_dependencies[i]->executablePath);
+    swiftscan_string_dispose(macro->macro_dependencies[i]->module_name);
+    swiftscan_string_dispose(macro->macro_dependencies[i]->library_path);
+    swiftscan_string_dispose(macro->macro_dependencies[i]->executable_path);
     delete macro->macro_dependencies[i];
   }
   delete[] macro->macro_dependencies;
@@ -61,6 +61,8 @@ void swiftscan_dependency_info_details_dispose(
         details_impl->swift_textual_details.bridging_module_dependencies);
     swiftscan_string_set_dispose(
         details_impl->swift_textual_details.swift_overlay_module_dependencies);
+    swiftscan_string_set_dispose(
+        details_impl->swift_textual_details.source_import_module_dependencies);
     swiftscan_string_set_dispose(
         details_impl->swift_textual_details.command_line);
     swiftscan_string_dispose(details_impl->swift_textual_details.context_hash);
@@ -91,14 +93,6 @@ void swiftscan_dependency_info_details_dispose(
     swiftscan_string_dispose(
         details_impl->swift_binary_details.user_module_version);
     break;
-  case SWIFTSCAN_DEPENDENCY_INFO_SWIFT_PLACEHOLDER:
-    swiftscan_string_dispose(
-        details_impl->swift_placeholder_details.compiled_module_path);
-    swiftscan_string_dispose(
-        details_impl->swift_placeholder_details.module_doc_path);
-    swiftscan_string_dispose(
-        details_impl->swift_placeholder_details.module_source_info_path);
-    break;
   case SWIFTSCAN_DEPENDENCY_INFO_CLANG:
     swiftscan_string_dispose(details_impl->clang_details.module_map_path);
     swiftscan_string_dispose(details_impl->clang_details.context_hash);
@@ -166,7 +160,7 @@ swiftscan_dependency_graph_create(swiftscan_scanner_t scanner,
 
   // Execute the scan and bridge the result
   auto ScanResult = ScanningTool->getDependencies(
-      Compilation, {},
+      Compilation,
       swift::c_string_utils::get_C_string(invocation->working_directory));
   if (ScanResult.getError())
     return nullptr;
@@ -238,12 +232,17 @@ swiftscan_link_library_set_t *swiftscan_module_info_get_link_libraries(
   return info->link_libraries;
 }
 
+swiftscan_import_info_set_t *swiftscan_module_info_get_imports(
+    swiftscan_dependency_info_t info) {
+  return info->imports;
+}
+
 swiftscan_module_details_t
 swiftscan_module_info_get_details(swiftscan_dependency_info_t info) {
   return info->details;
 }
 
-//=== Link Library Info query APIs -----------------------------------===//
+//=== Link Library Info query APIs ---------------------------------------===//
 
 swiftscan_string_ref_t
 swiftscan_link_library_info_get_link_name(swiftscan_link_library_info_t info) {
@@ -265,7 +264,23 @@ swiftscan_link_library_info_get_should_force_load(swiftscan_link_library_info_t
   return info->forceLoad;
 }
 
-//=== Swift Textual Module Details query APIs -----------------------------===//
+//=== Import Details Query APIs ------------------------------------------===//
+swiftscan_source_location_set_t *
+swiftscan_import_info_get_source_locations(swiftscan_import_info_t info) {
+  return info->source_locations;
+}
+
+swiftscan_string_ref_t
+swiftscan_import_info_get_identifier(swiftscan_import_info_t info) {
+  return info->import_identifier;
+}
+
+swiftscan_access_level_t
+swiftscan_import_info_get_access_level(swiftscan_import_info_t info) {
+  return info->access_level;
+}
+
+//=== Swift Textual Module Details query APIs ----------------------------===//
 
 swiftscan_dependency_info_kind_t
 swiftscan_module_detail_get_kind(swiftscan_module_details_t details) {
@@ -326,6 +341,11 @@ swiftscan_string_set_t *swiftscan_swift_textual_detail_get_swift_overlay_depende
   return details->swift_textual_details.swift_overlay_module_dependencies;
 }
 
+swiftscan_string_set_t *swiftscan_swift_textual_detail_get_swift_source_import_module_dependencies(
+    swiftscan_module_details_t details) {
+  return details->swift_textual_details.source_import_module_dependencies;
+}
+
 swiftscan_string_ref_t swiftscan_swift_textual_detail_get_cas_fs_root_id(
     swiftscan_module_details_t details) {
   return details->swift_textual_details.cas_fs_root_id;
@@ -405,23 +425,23 @@ swiftscan_swift_binary_detail_get_user_module_version(
   return details->swift_binary_details.user_module_version;
 }
 
-//=== Swift Placeholder Module Details query APIs -------------------------===//
+//=== Swift Placeholder Module Details query APIs - DEPRECATED -----------===//
 
 swiftscan_string_ref_t
 swiftscan_swift_placeholder_detail_get_compiled_module_path(
     swiftscan_module_details_t details) {
-  return details->swift_placeholder_details.module_source_info_path;
+  return swift::c_string_utils::create_null();
 }
 
 swiftscan_string_ref_t swiftscan_swift_placeholder_detail_get_module_doc_path(
     swiftscan_module_details_t details) {
-  return details->swift_placeholder_details.module_source_info_path;
+  return swift::c_string_utils::create_null();
 }
 
 swiftscan_string_ref_t
 swiftscan_swift_placeholder_detail_get_module_source_info_path(
     swiftscan_module_details_t details) {
-  return details->swift_placeholder_details.module_source_info_path;
+  return swift::c_string_utils::create_null();
 }
 
 //=== Clang Module Details query APIs -------------------------------------===//
@@ -582,45 +602,15 @@ swiftscan_compiler_supported_features_query() {
 //=== Scanner Diagnostics -------------------------------------------------===//
 swiftscan_diagnostic_set_t*
 swiftscan_scanner_diagnostics_query(swiftscan_scanner_t scanner) {
-  DependencyScanningTool *ScanningTool = unwrap(scanner);
-  auto Diagnostics = ScanningTool->getDiagnostics();
-  auto NumDiagnostics = Diagnostics.size();
-
-  swiftscan_diagnostic_set_t *Result = new swiftscan_diagnostic_set_t;
-  Result->count = NumDiagnostics;
-  Result->diagnostics = new swiftscan_diagnostic_info_t[NumDiagnostics];
-
-  for (size_t i = 0; i < NumDiagnostics; ++i) {
-    const auto &Diagnostic = Diagnostics[i];
-    swiftscan_diagnostic_info_s *DiagnosticInfo = new swiftscan_diagnostic_info_s;
-    DiagnosticInfo->message = swift::c_string_utils::create_clone(Diagnostic.Message.c_str());
-    switch (Diagnostic.Severity) {
-    case llvm::SourceMgr::DK_Error:
-      DiagnosticInfo->severity = SWIFTSCAN_DIAGNOSTIC_SEVERITY_ERROR;
-      break;
-    case llvm::SourceMgr::DK_Warning:
-      DiagnosticInfo->severity = SWIFTSCAN_DIAGNOSTIC_SEVERITY_WARNING;
-      break;
-    case llvm::SourceMgr::DK_Note:
-      DiagnosticInfo->severity = SWIFTSCAN_DIAGNOSTIC_SEVERITY_NOTE;
-      break;
-    case llvm::SourceMgr::DK_Remark:
-      DiagnosticInfo->severity = SWIFTSCAN_DIAGNOSTIC_SEVERITY_REMARK;
-      break;
-    }
-    // swiftscan_scanner_diagnostics_query is deprecated,
-    // so it does not support source locations.
-    DiagnosticInfo->source_location = nullptr;
-    Result->diagnostics[i] = DiagnosticInfo;
-  }
-
-  return Result;
+  // This method is deprecated
+  swiftscan_diagnostic_set_t *set = new swiftscan_diagnostic_set_t;
+  set->count = 0;
+  return set;
 }
 
 void
 swiftscan_scanner_diagnostics_reset(swiftscan_scanner_t scanner) {
-  DependencyScanningTool *ScanningTool = unwrap(scanner);
-  ScanningTool->resetDiagnostics();
+  // This method is deprecated
 }
 
 swiftscan_string_ref_t
diff --git a/lib/Tooling/libSwiftScan/libSwiftScan.exports b/lib/Tooling/libSwiftScan/libSwiftScan.exports
index a606b97eb5a02..9eb60935f12fc 100644
--- a/lib/Tooling/libSwiftScan/libSwiftScan.exports
+++ b/lib/Tooling/libSwiftScan/libSwiftScan.exports
@@ -5,11 +5,15 @@ swiftscan_link_library_info_get_link_name
 swiftscan_link_library_info_get_is_static
 swiftscan_link_library_info_get_is_framework
 swiftscan_link_library_info_get_should_force_load
+swiftscan_import_info_get_source_locations
+swiftscan_import_info_get_identifier
+swiftscan_import_info_get_access_level
 swiftscan_module_info_get_module_name
 swiftscan_module_info_get_module_path
 swiftscan_module_info_get_source_files
 swiftscan_module_info_get_direct_dependencies
 swiftscan_module_info_get_link_libraries
+swiftscan_module_info_get_imports
 swiftscan_module_info_get_details
 swiftscan_module_detail_get_kind
 swiftscan_swift_textual_detail_get_module_interface_path
@@ -22,6 +26,7 @@ swiftscan_swift_textual_detail_get_bridging_pch_command_line
 swiftscan_swift_textual_detail_get_context_hash
 swiftscan_swift_textual_detail_get_is_framework
 swiftscan_swift_textual_detail_get_swift_overlay_dependencies
+swiftscan_swift_textual_detail_get_swift_source_import_module_dependencies
 swiftscan_swift_textual_detail_get_cas_fs_root_id
 swiftscan_swift_textual_detail_get_module_cache_key
 swiftscan_swift_textual_detail_get_user_module_version
diff --git a/stdlib/CMakeLists.txt b/stdlib/CMakeLists.txt
index 9768a59a21ff1..710be1eb317ef 100644
--- a/stdlib/CMakeLists.txt
+++ b/stdlib/CMakeLists.txt
@@ -11,8 +11,13 @@ project(swift-stdlib LANGUAGES C CXX)
 # being built on Windows.  Since we know that we only support `clang-cl` as the
 # compiler for the runtime due to the use of the Swift calling convention, we
 # simply override the CMake behaviour unconditionally.
-set(CMAKE_INCLUDE_SYSTEM_FLAG_C "-Isystem")
-set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX "-Isystem")
+if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
+  set(CMAKE_INCLUDE_SYSTEM_FLAG_C "-imsvc ")
+  set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX "-imsvc ")
+else()
+  set(CMAKE_INCLUDE_SYSTEM_FLAG_C "-Isystem")
+  set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX "-Isystem")
+endif()
 
 # Add path for custom CMake modules.
 list(APPEND CMAKE_MODULE_PATH
diff --git a/stdlib/cmake/WindowsVFS.yaml.in b/stdlib/cmake/WindowsVFS.yaml.in
index 743915a6e5e87..9a728125ebd74 100644
--- a/stdlib/cmake/WindowsVFS.yaml.in
+++ b/stdlib/cmake/WindowsVFS.yaml.in
@@ -8,7 +8,13 @@ roots:
     contents:
       - name: module.modulemap
         type: file
-        external-contents: "@PROJECT_SOURCE_DIR@\\public\\Platform\\winsdk.modulemap"
+        external-contents: "@PROJECT_SOURCE_DIR@\\public\\Platform\\winsdk_um.modulemap"
+  - name: "@UniversalCRTSdkDir@\\Include\\@UCRTVersion@\\shared"
+    type: directory
+    contents:
+      - name: module.modulemap
+        type: file
+        external-contents: "@PROJECT_SOURCE_DIR@\\public\\Platform\\winsdk_shared.modulemap"
   - name: "@UniversalCRTSdkDir@\\Include\\@UCRTVersion@\\ucrt"
     type: directory
     contents:
diff --git a/stdlib/cmake/modules/AddSwiftStdlib.cmake b/stdlib/cmake/modules/AddSwiftStdlib.cmake
index d8560393d8023..e47c9db33ab65 100644
--- a/stdlib/cmake/modules/AddSwiftStdlib.cmake
+++ b/stdlib/cmake/modules/AddSwiftStdlib.cmake
@@ -19,6 +19,52 @@ function(add_dependencies_multiple_targets)
   endif()
 endfunction()
 
+# Compute the deployment version
+function(deployment_version result_var_name)
+  set(arguments
+    SDK
+    DEPLOYMENT_VERSION_OSX
+    DEPLOYMENT_VERSION_IOS
+    DEPLOYMENT_VERSION_TVOS
+    DEPLOYMENT_VERSION_WATCHOS
+    DEPLOYMENT_VERSION_XROS
+  )
+  cmake_parse_arguments(GETDEP
+    ""
+    "${arguments}"
+    ""
+    ${ARGN})
+
+  if("${GETDEP_SDK}" IN_LIST SWIFT_DARWIN_PLATFORMS)
+    # Check if there's a specific OS deployment version needed for this invocation
+    if("${GETDEP_SDK}" STREQUAL "OSX")
+      set(DEPLOYMENT_VERSION ${GETDEP_DEPLOYMENT_VERSION_OSX})
+    elseif("${GETDEP_SDK}" STREQUAL "IOS" OR "${GETDEP_SDK}" STREQUAL "IOS_SIMULATOR")
+      set(DEPLOYMENT_VERSION ${GETDEP_DEPLOYMENT_VERSION_IOS})
+    elseif("${GETDEP_SDK}" STREQUAL "TVOS" OR "${GETDEP_SDK}" STREQUAL "TVOS_SIMULATOR")
+      set(DEPLOYMENT_VERSION ${GETDEP_DEPLOYMENT_VERSION_TVOS})
+    elseif("${GETDEP_SDK}" STREQUAL "WATCHOS" OR "${GETDEP_SDK}" STREQUAL "WATCHOS_SIMULATOR")
+      set(DEPLOYMENT_VERSION ${GETDEP_DEPLOYMENT_VERSION_WATCHOS})
+    elseif("${GETDEP_SDK}" STREQUAL "XROS" OR "${GETDEP_SDK}" STREQUAL "XROS_SIMULATOR")
+      set(DEPLOYMENT_VERSION ${GETDEP_DEPLOYMENT_VERSION_XROS})
+    endif()
+
+    if("${DEPLOYMENT_VERSION}" STREQUAL "")
+      set(DEPLOYMENT_VERSION "${SWIFT_SDK_${GETDEP_SDK}_DEPLOYMENT_VERSION}")
+    endif()
+  endif()
+
+  if("${GETDEP_SDK}" STREQUAL "ANDROID")
+    set(DEPLOYMENT_VERSION ${SWIFT_ANDROID_API_LEVEL})
+  endif()
+
+  if("${GETDEP_SDK}" STREQUAL "FREESTANDING")
+    set(DEPLOYMENT_VERSION "${SWIFT_SDK_${GETDEP_SDK}_DEPLOYMENT_VERSION}")
+  endif()
+
+  set("${result_var_name}" "${DEPLOYMENT_VERSION}" PARENT_SCOPE)
+endfunction()
+
 # Usage:
 # _add_target_variant_c_compile_link_flags(
 #   SDK sdk
@@ -52,32 +98,19 @@ function(_add_target_variant_c_compile_link_flags)
 
   set(result ${${CFLAGS_RESULT_VAR_NAME}})
 
-  if("${CFLAGS_SDK}" IN_LIST SWIFT_DARWIN_PLATFORMS)
-    # Check if there's a specific OS deployment version needed for this invocation
-    if("${CFLAGS_SDK}" STREQUAL "OSX")
-      if(DEFINED maccatalyst_build_flavor AND DEFINED CFLAGS_DEPLOYMENT_VERSION_MACCATALYST)
-        set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_MACCATALYST})
-      else()
-        set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_OSX})
-      endif()
-    elseif("${CFLAGS_SDK}" STREQUAL "IOS" OR "${CFLAGS_SDK}" STREQUAL "IOS_SIMULATOR")
-      set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_IOS})
-    elseif("${CFLAGS_SDK}" STREQUAL "TVOS" OR "${CFLAGS_SDK}" STREQUAL "TVOS_SIMULATOR")
-      set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_TVOS})
-    elseif("${CFLAGS_SDK}" STREQUAL "WATCHOS" OR "${CFLAGS_SDK}" STREQUAL "WATCHOS_SIMULATOR")
-      set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_WATCHOS})
-    elseif("${CFLAGS_SDK}" STREQUAL "XROS" OR "${CFLAGS_SDK}" STREQUAL "XROS_SIMULATOR")
-      set(DEPLOYMENT_VERSION ${CFLAGS_DEPLOYMENT_VERSION_XROS})
-    endif()
-
-    if("${DEPLOYMENT_VERSION}" STREQUAL "")
-      set(DEPLOYMENT_VERSION "${SWIFT_SDK_${CFLAGS_SDK}_DEPLOYMENT_VERSION}")
-    endif()
+  if(DEFINED maccatalyst_build_flavor AND DEFINED CFLAGS_DEPLOYMENT_VERSION_MACCATALYST)
+    set(DEPLOYMENT_VERSION_OSX "${CFLAGS_DEPLOYMENT_VERSION_MACCATALYST}")
+  else()
+    set(DEPLOYMENT_VERSION_OSX "${CFLAGS_DEPLOYMENT_VERSION_OSX}")
   endif()
 
-  if("${CFLAGS_SDK}" STREQUAL "ANDROID")
-    set(DEPLOYMENT_VERSION ${SWIFT_ANDROID_API_LEVEL})
-  endif()
+  deployment_version(DEPLOYMENT_VERSION
+    SDK ${CFLAGS_SDK}
+    DEPLOYMENT_VERSION_OSX "${DEPLOYMENT_VERSION_OSX}"
+    DEPLOYMENT_VERSION_IOS "${CFLAGS_DEPLOYMENT_VERSION_IOS}"
+    DEPLOYMENT_VERSION_TVOS "${CFLAGS_DEPLOYMENT_VERSION_TVOS}"
+    DEPLOYMENT_VERSION_WATCHOS "${CFLAGS_DEPLOYMENT_VERSION_WATCHOS}"
+    DEPLOYMENT_VERSION_XROS "${CFLAGS_DEPLOYMENT_VERSION_XROS}")
 
   # MSVC, clang-cl, gcc don't understand -target.
   if(CMAKE_C_COMPILER_ID MATCHES "^Clang|AppleClang$" AND
@@ -721,6 +754,8 @@ endfunction()
 #     [DONT_EMBED_BITCODE]
 #     [IS_STDLIB]
 #     [IS_STDLIB_CORE]
+#     [ONLY_SWIFTMODULE]
+#     [NO_SWIFTMODULE]
 #     [IS_SDK_OVERLAY]
 #     [IS_FRAGILE]
 #     INSTALL_IN_COMPONENT comp
@@ -742,9 +777,6 @@ endfunction()
 # STATIC
 #   Build a static library.
 #
-# ONLY_SWIFTMODULE
-#   Do not build either static or shared, build just the .swiftmodule.
-#
 # SDK sdk
 #   SDK to build for.
 #
@@ -784,6 +816,12 @@ endfunction()
 # IS_STDLIB_CORE
 #   Compile as the standard library core.
 #
+# ONLY_SWIFTMODULE
+#   Do not build either static or shared, build just the .swiftmodule.
+#
+# NO_SWIFTMODULE
+#   Only build either static or shared, and skip the .swiftmodule.
+#
 # IS_SDK_OVERLAY
 #   Treat the library as a part of the Swift SDK overlay.
 #
@@ -811,11 +849,13 @@ function(add_swift_target_library_single target name)
         SHARED
         STATIC
         ONLY_SWIFTMODULE
+        NO_SWIFTMODULE
         NO_LINK_NAME
         INSTALL_WITH_SHARED
         IS_FRAGILE)
   set(SWIFTLIB_SINGLE_single_parameter_options
         ARCHITECTURE
+        ARCHITECTURE_SUBDIR_NAME
         DEPLOYMENT_VERSION_IOS
         DEPLOYMENT_VERSION_OSX
         DEPLOYMENT_VERSION_TVOS
@@ -882,6 +922,9 @@ function(add_swift_target_library_single target name)
   precondition(SWIFTLIB_SINGLE_SDK MESSAGE "Should specify an SDK")
   precondition(SWIFTLIB_SINGLE_ARCHITECTURE MESSAGE "Should specify an architecture")
   precondition(SWIFTLIB_SINGLE_INSTALL_IN_COMPONENT MESSAGE "INSTALL_IN_COMPONENT is required")
+  if (NOT SWIFTLIB_SINGLE_ARCHITECTURE_SUBDIR_NAME)
+    set(SWIFTLIB_SINGLE_ARCHITECTURE_SUBDIR_NAME "${SWIFTLIB_SINGLE_ARCHITECTURE}")
+  endif()
 
   if(NOT SWIFTLIB_SINGLE_SHARED AND
      NOT SWIFTLIB_SINGLE_STATIC AND
@@ -897,12 +940,12 @@ function(add_swift_target_library_single target name)
 
   # Determine the subdirectory where this library will be installed.
   set(SWIFTLIB_SINGLE_SUBDIR
-      "${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}/${SWIFTLIB_SINGLE_ARCHITECTURE}")
+      "${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}/${SWIFTLIB_SINGLE_ARCHITECTURE_SUBDIR_NAME}")
 
   # macCatalyst ios-like builds are installed in the maccatalyst/x86_64 directory
   if(maccatalyst_build_flavor STREQUAL "ios-like")
     set(SWIFTLIB_SINGLE_SUBDIR
-        "${SWIFT_SDK_MACCATALYST_LIB_SUBDIR}/${SWIFTLIB_SINGLE_ARCHITECTURE}")
+        "${SWIFT_SDK_MACCATALYST_LIB_SUBDIR}/${SWIFTLIB_SINGLE_ARCHITECTURE_SUBDIR_NAME}")
   endif()
 
   if ("${SWIFTLIB_SINGLE_BOOTSTRAPPING}" STREQUAL "")
@@ -926,11 +969,14 @@ function(add_swift_target_library_single target name)
     endif()
   endif()
 
-  # FIXME: swiftDarwin currently trips an assertion in SymbolGraphGen
-  if (SWIFTLIB_IS_STDLIB AND SWIFT_STDLIB_BUILD_SYMBOL_GRAPHS AND NOT ${name} STREQUAL "swiftDarwin")
+  # FIXME: swiftDarwin and swiftDifferentiationUnittest currently trip an assertion in SymbolGraphGen
+  if (SWIFTLIB_IS_STDLIB AND SWIFT_STDLIB_BUILD_SYMBOL_GRAPHS AND NOT ${name} STREQUAL "swiftDarwin"
+      AND NOT ${name} STREQUAL "swiftDifferentiationUnittest")
     list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS "-Xfrontend;-emit-symbol-graph")
     list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS
          "-Xfrontend;-emit-symbol-graph-dir;-Xfrontend;${out_lib_dir}/symbol-graph/${VARIANT_NAME}")
+    list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS
+         "-Xfrontend;-symbol-graph-allow-availability-platforms;-Xfrontend;Swift")
   endif()
 
   if(MODULE)
@@ -988,8 +1034,51 @@ function(add_swift_target_library_single target name)
   endif()
 
   # Define availability macros.
+  deployment_version(DEPLOYMENT_VERSION
+    SDK "${SWIFTLIB_SINGLE_SDK}"
+    DEPLOYMENT_VERSION_OSX "${SWIFTLIB_SINGLE_DEPLOYMENT_VERSION_OSX}"
+    DEPLOYMENT_VERSION_IOS "${SWIFTLIB_SINGLE_DEPLOYMENT_VERSION_IOS}"
+    DEPLOYMENT_VERSION_TVOS "${SWIFTLIB_SINGLE_DEPLOYMENT_VERSION_TVOS}"
+    DEPLOYMENT_VERSION_WATCHOS "${SWIFTLIB_SINGLE_DEPLOYMENT_VERSION_WATCHOS}"
+    DEPLOYMENT_VERSION_XROS "${SWIFTLIB_SINGLE_DEPLOYMENT_VERSION_XROS}")
+
   foreach(def ${SWIFT_STDLIB_AVAILABILITY_DEFINITIONS})
     list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS "-Xfrontend" "-define-availability" "-Xfrontend" "${def}")
+
+    if("${def}" MATCHES "SwiftStdlib .*")
+      # For each SwiftStdlib x.y, also define StdlibDeploymentTarget x.y, which,
+      # will expand to the current `-target` platform if the macro defines a
+      # newer platform as its availability.
+      #
+      # There is a setting, SWIFT_STDLIB_ENABLE_STRICT_AVAILABILITY, which if set
+      # ON will cause us to use the "proper" availability instead.
+      string(REPLACE "SwiftStdlib" "StdlibDeploymentTarget" current "${def}")
+      if(NOT SWIFT_STDLIB_ENABLE_STRICT_AVAILABILITY AND SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_AVAILABILITY_NAME)
+        if(SWIFTLIB_SINGLE_SDK STREQUAL "OSX" AND SWIFTLIB_SINGLE_MACCATALYST_BUILD_FLAVOR STREQUAL "ios-like")
+          string(REGEX MATCH "iOS ([0-9]+(\.[0-9]+)+)" platform_version "${def}")
+          string(REGEX MATCH "[0-9]+(\.[0-9]+)+" version "${platform_version}")
+          if(NOT version STREQUAL "9999" AND version VERSION_GREATER "${SWIFT_DARWIN_DEPLOYMENT_VERSION_MACCATALYST}")
+            string(REGEX REPLACE ":.*" ":iOS ${SWIFT_DARWIN_DEPLOYMENT_VERSION_MACCATALYST}" current "${current}")
+          endif()
+        elseif(SWIFTLIB_SINGLE_SDK STREQUAL "OSX" AND SWIFTLIB_SINGLE_MACCATALYST_BUILD_FLAVOR STREQUAL "zippered")
+          string(REGEX MATCH "iOS ([0-9]+(\.[0-9]+)+)" ios_platform_version "${def}")
+          string(REGEX MATCH "[0-9]+(\.[0-9]+)+" ios_version "${ios_platform_version}")
+          string(REGEX MATCH "macOS ([0-9]+(\.[0-9]+)+)" macos_platform_version "${def}")
+          string(REGEX MATCH "[0-9]+(\.[0-9]+)+" macos_version "${macos_platform_version}")
+          if((NOT macos_version STREQUAL "9999" OR NOT ios_version STREQUAL "9999") AND (macos_version VERSION_GREATER "${DEPLOYMENT_VERSION}" OR ios_version VERSION_GREATER "${SWIFT_DARWIN_DEPLOYMENT_VERSION_MACCATALYST}"))
+            string(REGEX REPLACE ":.*" ": macOS ${DEPLOYMENT_VERSION}, iOS ${SWIFT_DARWIN_DEPLOYMENT_VERSION_MACCATALYST}" current "${current}")
+          endif()
+        else()
+          string(REGEX MATCH "${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_AVAILABILITY_NAME} ([0-9]+(\.[0-9]+)+)" platform_version "${def}")
+          string(REGEX MATCH "[0-9]+(\.[0-9]+)+" version "${platform_version}")
+          if(NOT version STREQUAL "9999" AND version VERSION_GREATER "${DEPLOYMENT_VERSION}")
+            string(REGEX REPLACE ":.*" ":${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_AVAILABILITY_NAME} ${DEPLOYMENT_VERSION}" current "${current}")
+          endif()
+        endif()
+      endif()
+
+      list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS "-Xfrontend" "-define-availability" "-Xfrontend" "${current}")
+    endif()
   endforeach()
 
   # Enable -target-min-inlining-version
@@ -1024,6 +1113,7 @@ function(add_swift_target_library_single target name)
         ${SWIFTLIB_SINGLE_LINK_LIBRARIES}
       SDK ${SWIFTLIB_SINGLE_SDK}
       ARCHITECTURE ${SWIFTLIB_SINGLE_ARCHITECTURE}
+      ARCHITECTURE_SUBDIR_NAME ${SWIFTLIB_SINGLE_ARCHITECTURE_SUBDIR_NAME}
       MODULE_NAME ${module_name}
       MODULE_DIR ${SWIFTLIB_SINGLE_MODULE_DIR}
       COMPILE_FLAGS ${SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS}
@@ -1032,6 +1122,7 @@ function(add_swift_target_library_single target name)
       ${SWIFTLIB_SINGLE_IS_SDK_OVERLAY_keyword}
       ${SWIFTLIB_SINGLE_IS_FRAGILE_keyword}
       ${SWIFTLIB_SINGLE_ONLY_SWIFTMODULE_keyword}
+      ${SWIFTLIB_SINGLE_NO_SWIFTMODULE_keyword}
       ${embed_bitcode_arg}
       ${SWIFTLIB_SINGLE_STATIC_keyword}
       ${SWIFTLIB_SINGLE_NO_LINK_NAME_keyword}
@@ -1048,9 +1139,9 @@ function(add_swift_target_library_single target name)
 
   # If there were any swift sources, then a .swiftmodule may have been created.
   # If that is the case, then add a target which is an alias of the module files.
-  set(VARIANT_SUFFIX "-${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}-${SWIFTLIB_SINGLE_ARCHITECTURE}")
+  set(VARIANT_SUFFIX "-${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}-${SWIFTLIB_SINGLE_ARCHITECTURE_SUBDIR_NAME}")
   if(maccatalyst_build_flavor STREQUAL "ios-like")
-    set(VARIANT_SUFFIX "-${SWIFT_SDK_MACCATALYST_LIB_SUBDIR}-${SWIFTLIB_SINGLE_ARCHITECTURE}")
+    set(VARIANT_SUFFIX "-${SWIFT_SDK_MACCATALYST_LIB_SUBDIR}-${SWIFTLIB_SINGLE_ARCHITECTURE_SUBDIR_NAME}")
   endif()
 
   if(NOT "${SWIFTLIB_SINGLE_MODULE_TARGETS}" STREQUAL "" AND NOT "${swift_module_dependency_target}" STREQUAL "")
@@ -1683,6 +1774,8 @@ endfunction()
 #     [INSTALL]
 #     [IS_STDLIB]
 #     [IS_STDLIB_CORE]
+#     [ONLY_SWIFTMODULE]
+#     [NO_SWIFTMODULE]
 #     [INSTALL_WITH_SHARED]
 #     INSTALL_IN_COMPONENT comp
 #     DEPLOYMENT_VERSION_OSX version
@@ -1791,6 +1884,12 @@ endfunction()
 # IS_STDLIB_CORE
 #   Compile as the Swift standard library core.
 #
+# ONLY_SWIFTMODULE
+#   Do not build either static or shared, build just the .swiftmodule.
+#
+# NO_SWIFTMODULE
+#   Only build either static or shared, and skip the .swiftmodule.
+#
 # IS_SDK_OVERLAY
 #   Treat the library as a part of the Swift SDK overlay.
 #
@@ -1821,9 +1920,6 @@ endfunction()
 # INSTALL_WITH_SHARED
 #   Install a static library target alongside shared libraries
 #
-# IMPORTS_NON_OSSA
-#   Imports a non-ossa module
-#
 # MACCATALYST_BUILD_FLAVOR
 #   Possible values are 'ios-like', 'macos-like', 'zippered', 'unzippered-twin'
 #   Presence of a build flavor requires SWIFT_MODULE_DEPENDS_MACCATALYST to be
@@ -1879,12 +1975,13 @@ function(add_swift_target_library name)
         IS_STDLIB_CORE
         IS_SWIFT_ONLY
         NOSWIFTRT
+        ONLY_SWIFTMODULE
+        NO_SWIFTMODULE
         OBJECT_LIBRARY
         SHARED
         STATIC
         NO_LINK_NAME
-        INSTALL_WITH_SHARED
-        IMPORTS_NON_OSSA)
+        INSTALL_WITH_SHARED)
   set(SWIFTLIB_single_parameter_options
         DEPLOYMENT_VERSION_IOS
         DEPLOYMENT_VERSION_OSX
@@ -2049,10 +2146,6 @@ function(add_swift_target_library name)
     list(APPEND SWIFTLIB_SWIFT_COMPILE_FLAGS "-Xfrontend;-enable-lexical-lifetimes=false")
   endif()
 
-  if (NOT SWIFTLIB_IMPORTS_NON_OSSA)
-    list(APPEND SWIFTLIB_SWIFT_COMPILE_FLAGS "-Xfrontend;-enable-ossa-modules")
-  endif()
-
   if(NOT DEFINED SWIFTLIB_INSTALL_BINARY_SWIFTMODULE)
     set(SWIFTLIB_INSTALL_BINARY_SWIFTMODULE TRUE)
   endif()
@@ -2444,6 +2537,8 @@ function(add_swift_target_library name)
         list(APPEND swiftlib_link_flags_all "-shared")
         # TODO: Instead of `lib${name}.so` find variable or target property which already have this value.
         list(APPEND swiftlib_link_flags_all "-Wl,-soname,lib${name}.so")
+        # Ensure compatibility with Android 15+ devices using 16KB memory pages.
+        list(APPEND swiftlib_link_flags_all "-Wl,-z,max-page-size=16384")
       endif()
 
       if (SWIFTLIB_BACK_DEPLOYMENT_LIBRARY)
@@ -2490,6 +2585,8 @@ function(add_swift_target_library name)
         ${SWIFTLIB_IS_STDLIB_CORE_keyword}
         ${SWIFTLIB_IS_SDK_OVERLAY_keyword}
         ${SWIFTLIB_NOSWIFTRT_keyword}
+        ${SWIFTLIB_ONLY_SWIFTMODULE_keyword}
+        ${SWIFTLIB_NO_SWIFTMODULE_keyword}
         DARWIN_INSTALL_NAME_DIR "${SWIFTLIB_DARWIN_INSTALL_NAME_DIR}"
         INSTALL_IN_COMPONENT "${SWIFTLIB_INSTALL_IN_COMPONENT}"
         DEPLOYMENT_VERSION_OSX "${SWIFTLIB_DEPLOYMENT_VERSION_OSX}"
diff --git a/stdlib/cmake/modules/SwiftSource.cmake b/stdlib/cmake/modules/SwiftSource.cmake
index 6f85621f62a91..98ead31c28e32 100644
--- a/stdlib/cmake/modules/SwiftSource.cmake
+++ b/stdlib/cmake/modules/SwiftSource.cmake
@@ -49,8 +49,8 @@ function(handle_swift_sources
     dependency_sibgen_target_out_var_name
     sourcesvar externalvar name)
   cmake_parse_arguments(SWIFTSOURCES
-      "IS_MAIN;IS_STDLIB;IS_STDLIB_CORE;IS_SDK_OVERLAY;EMBED_BITCODE;STATIC;NO_LINK_NAME;IS_FRAGILE;ONLY_SWIFTMODULE"
-      "SDK;ARCHITECTURE;INSTALL_IN_COMPONENT;DEPLOYMENT_VERSION_OSX;DEPLOYMENT_VERSION_IOS;DEPLOYMENT_VERSION_TVOS;DEPLOYMENT_VERSION_WATCHOS;MACCATALYST_BUILD_FLAVOR;BOOTSTRAPPING;INSTALL_BINARY_SWIFTMODULE"
+      "IS_MAIN;IS_STDLIB;IS_STDLIB_CORE;IS_SDK_OVERLAY;EMBED_BITCODE;STATIC;NO_LINK_NAME;IS_FRAGILE;ONLY_SWIFTMODULE;NO_SWIFTMODULE"
+      "SDK;ARCHITECTURE;ARCHITECTURE_SUBDIR_NAME;INSTALL_IN_COMPONENT;DEPLOYMENT_VERSION_OSX;DEPLOYMENT_VERSION_IOS;DEPLOYMENT_VERSION_TVOS;DEPLOYMENT_VERSION_WATCHOS;MACCATALYST_BUILD_FLAVOR;BOOTSTRAPPING;INSTALL_BINARY_SWIFTMODULE"
       "DEPENDS;COMPILE_FLAGS;MODULE_NAME;MODULE_DIR;ENABLE_LTO"
       ${ARGN})
   translate_flag(${SWIFTSOURCES_IS_MAIN} "IS_MAIN" IS_MAIN_arg)
@@ -66,6 +66,7 @@ function(handle_swift_sources
   translate_flag(${SWIFTSOURCES_NO_LINK_NAME} "NO_LINK_NAME" NO_LINK_NAME_arg)
   translate_flag(${SWIFTSOURCES_IS_FRAGILE} "IS_FRAGILE" IS_FRAGILE_arg)
   translate_flag(${SWIFTSOURCES_ONLY_SWIFTMODULE} "ONLY_SWIFTMODULE" ONLY_SWIFTMODULE_arg)
+  translate_flag(${SWIFTSOURCES_NO_SWIFTMODULE} "NO_SWIFTMODULE" NO_SWIFTMODULE_arg)
   if(DEFINED SWIFTSOURCES_BOOTSTRAPPING)
     set(BOOTSTRAPPING_arg "BOOTSTRAPPING" ${SWIFTSOURCES_BOOTSTRAPPING})
   endif()
@@ -82,6 +83,9 @@ function(handle_swift_sources
   precondition(SWIFTSOURCES_SDK "Should specify an SDK")
   precondition(SWIFTSOURCES_ARCHITECTURE "Should specify an architecture")
   precondition(SWIFTSOURCES_INSTALL_IN_COMPONENT "INSTALL_IN_COMPONENT is required")
+  if (NOT SWIFTSOURCES_ARCHITECTURE_SUBDIR_NAME)
+    set(SWIFTSOURCES_ARCHITECTURE_SUBDIR_NAME "${SWIFTSOURCES_ARCHITECTURE}")
+  endif()
 
   # Clear the result variable.
   set("${dependency_target_out_var_name}" "" PARENT_SCOPE)
@@ -107,12 +111,12 @@ function(handle_swift_sources
   endif()
 
   if(swift_sources)
-    set(objsubdir "/${SWIFTSOURCES_SDK}/${SWIFTSOURCES_ARCHITECTURE}")
+    set(objsubdir "/${SWIFTSOURCES_SDK}/${SWIFTSOURCES_ARCHITECTURE_SUBDIR_NAME}")
 
     get_maccatalyst_build_flavor(maccatalyst_build_flavor
       "${SWIFTSOURCES_SDK}" "${SWIFTSOURCES_MACCATALYST_BUILD_FLAVOR}")
     if(maccatalyst_build_flavor STREQUAL "ios-like")
-      set(objsubdir "/MACCATALYST/${SWIFTSOURCES_ARCHITECTURE}")
+      set(objsubdir "/MACCATALYST/${SWIFTSOURCES_ARCHITECTURE_SUBDIR_NAME}")
     endif()
 
     get_bootstrapping_path(lib_dir
@@ -161,6 +165,7 @@ function(handle_swift_sources
         ${BOOTSTRAPPING_arg}
         ${IS_FRAGILE_arg}
         ${ONLY_SWIFTMODULE_arg}
+        ${NO_SWIFTMODULE_arg}
         INSTALL_BINARY_SWIFTMODULE ${SWIFTSOURCES_INSTALL_BINARY_SWIFTMODULE}
         INSTALL_IN_COMPONENT "${SWIFTSOURCES_INSTALL_IN_COMPONENT}"
         DEPLOYMENT_VERSION_OSX ${SWIFTSOURCES_DEPLOYMENT_VERSION_OSX}
@@ -405,6 +410,8 @@ endfunction()
 #     [IS_MAIN]                         # This is an executable, not a library
 #     [IS_STDLIB]
 #     [IS_STDLIB_CORE]                  # This is the core standard library
+#     [ONLY_SWIFTMODULE]                # Emit swiftmodule only, no binary
+#     [NO_SWIFTMODULE]                  # Emit binary only, no swiftmodule
 #     [OPT_FLAGS]                       # Optimization flags (overrides SWIFT_OPTIMIZE)
 #     [MODULE_DIR]                      # Put .swiftmodule, .swiftdoc., and .o
 #                                       # into this directory.
@@ -419,7 +426,7 @@ function(_compile_swift_files
     dependency_sib_target_out_var_name dependency_sibopt_target_out_var_name
     dependency_sibgen_target_out_var_name)
   cmake_parse_arguments(SWIFTFILE
-    "IS_MAIN;IS_STDLIB;IS_STDLIB_CORE;IS_SDK_OVERLAY;EMBED_BITCODE;STATIC;IS_FRAGILE;ONLY_SWIFTMODULE"
+    "IS_MAIN;IS_STDLIB;IS_STDLIB_CORE;IS_SDK_OVERLAY;EMBED_BITCODE;STATIC;IS_FRAGILE;ONLY_SWIFTMODULE;NO_SWIFTMODULE"
     "OUTPUT;MODULE_NAME;INSTALL_IN_COMPONENT;DEPLOYMENT_VERSION_OSX;DEPLOYMENT_VERSION_IOS;DEPLOYMENT_VERSION_TVOS;DEPLOYMENT_VERSION_WATCHOS;MACCATALYST_BUILD_FLAVOR;BOOTSTRAPPING;INSTALL_BINARY_SWIFTMODULE"
     "SOURCES;FLAGS;DEPENDS;SDK;ARCHITECTURE;OPT_FLAGS;MODULE_DIR"
     ${ARGN})
@@ -631,6 +638,8 @@ function(_compile_swift_files
 
   list(APPEND swift_flags "-enable-experimental-feature" "NonescapableTypes")
   list(APPEND swift_flags "-enable-experimental-feature" "LifetimeDependence")
+  list(APPEND swift_flags "-enable-experimental-feature" "InoutLifetimeDependence")
+  list(APPEND swift_flags "-enable-experimental-feature" "LifetimeDependenceMutableAccessors")
 
   list(APPEND swift_flags "-enable-upcoming-feature" "MemberImportVisibility")
 
@@ -677,6 +686,10 @@ function(_compile_swift_files
   get_bootstrapping_path(lib_dir ${SWIFTLIB_DIR} "${SWIFTFILE_BOOTSTRAPPING}")
 
   if(NOT SWIFTFILE_IS_MAIN)
+    list(APPEND swift_flags "-parse-as-library")
+  endif()
+
+  if(NOT SWIFTFILE_IS_MAIN AND NOT SWIFTFILE_NO_SWIFTMODULE)
     # Determine the directory where the module file should be placed.
     if(SWIFTFILE_MODULE_DIR)
       set(module_dir "${SWIFTFILE_MODULE_DIR}")
@@ -686,8 +699,6 @@ function(_compile_swift_files
       message(FATAL_ERROR "Don't know where to put the module files")
     endif()
 
-    list(APPEND swift_flags "-parse-as-library")
-
     set(module_base "${module_dir}/${SWIFTFILE_MODULE_NAME}")
 
     set(module_dir_static "${SWIFTSTATICLIB_DIR}/${library_subdir}")
@@ -738,7 +749,9 @@ function(_compile_swift_files
     endif()
 
     set(exclude_binary_swiftmodule_installation_args "")
-    if(NOT SWIFTFILE_INSTALL_BINARY_SWIFTMODULE)
+    if(NOT SWIFTFILE_INSTALL_BINARY_SWIFTMODULE OR
+       (SWIFTFILE_INSTALL_BINARY_SWIFTMODULE STREQUAL "NON_DARWIN_ONLY" AND
+        SWIFTFILE_SDK IN_LIST SWIFT_DARWIN_PLATFORMS))
         list(APPEND
           exclude_binary_swiftmodule_installation_args
           "REGEX" "${SWIFTFILE_MODULE_NAME}.swiftmodule/[^/]*\\.swiftmodule$" EXCLUDE)
@@ -915,9 +928,9 @@ function(_compile_swift_files
   endif()
 
   set(custom_env "PYTHONIOENCODING=UTF8")
-  if(SWIFTFILE_IS_STDLIB OR
+  if(SWIFT_INCLUDE_TOOLS AND (SWIFTFILE_IS_STDLIB OR
      # Linux "hosttools" build require builder's runtime before building the runtime.
-     (BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS" AND SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
+     (BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS" AND SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD"))
   )
     get_bootstrapping_swift_lib_dir(bs_lib_dir "${SWIFTFILE_BOOTSTRAPPING}")
     if(bs_lib_dir)
@@ -1002,13 +1015,13 @@ function(_compile_swift_files
   # need to work around this by avoiding long command line arguments. This can
   # be achieved by writing the list of file paths to a file, then reading that
   # list in the Python script.
-  string(REPLACE ";" "'\n'" source_files_quoted "${source_files}")
-  string(SHA1 file_name "'${source_files_quoted}'")
+  string(REPLACE ";" "\n" source_files_quoted "${source_files}")
+  string(SHA1 file_name "${source_files_quoted}")
   set(file_path_target "filelist-${file_name}")
   set(file_path "${CMAKE_CURRENT_BINARY_DIR}/${file_name}.txt")
 
   if (NOT TARGET ${file_path_target})
-    file(WRITE "${file_path}.tmp" "'${source_files_quoted}'")
+    file(WRITE "${file_path}.tmp" "${source_files_quoted}")
     add_custom_command_target(unused_var
       COMMAND ${CMAKE_COMMAND} -E copy_if_different "${file_path}.tmp" "${file_path}"
       CUSTOM_TARGET_NAME ${file_path_target}
@@ -1067,7 +1080,7 @@ function(_compile_swift_files
   #
   # We only build these when we are not producing a main file. We could do this
   # with sib/sibgen, but it is useful for looking at the stdlib.
-  if (NOT SWIFTFILE_IS_MAIN)
+  if (NOT SWIFTFILE_IS_MAIN AND NOT SWIFTFILE_NO_SWIFTMODULE)
     add_custom_command_target(
         module_dependency_target
         COMMAND
diff --git a/stdlib/include/llvm/ADT/SmallVector.h b/stdlib/include/llvm/ADT/SmallVector.h
index 56b9e6063025a..ca651fc8845a6 100644
--- a/stdlib/include/llvm/ADT/SmallVector.h
+++ b/stdlib/include/llvm/ADT/SmallVector.h
@@ -21,6 +21,7 @@
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
+#include <cstdint>
 #include <cstdlib>
 #include <cstring>
 #include <functional>
diff --git a/stdlib/include/llvm/Support/Compiler.h b/stdlib/include/llvm/Support/Compiler.h
index 6d5d4748a3c77..86534d2b4ff42 100644
--- a/stdlib/include/llvm/Support/Compiler.h
+++ b/stdlib/include/llvm/Support/Compiler.h
@@ -142,6 +142,23 @@
 #define LLVM_ATTRIBUTE_USED
 #endif
 
+/// LLVM_NODISCARD - Warn if a type or return value is discarded.
+
+// Use the 'nodiscard' attribute in C++17 or newer mode.
+#if defined(__cplusplus) && __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(nodiscard)
+#define LLVM_NODISCARD [[nodiscard]]
+#elif LLVM_HAS_CPP_ATTRIBUTE(clang::warn_unused_result)
+#define LLVM_NODISCARD [[clang::warn_unused_result]]
+// Clang in C++14 mode claims that it has the 'nodiscard' attribute, but also
+// warns in the pedantic mode that 'nodiscard' is a C++17 extension (PR33518).
+// Use the 'nodiscard' attribute in C++14 mode only with GCC.
+// TODO: remove this workaround when PR33518 is resolved.
+#elif defined(__GNUC__) && LLVM_HAS_CPP_ATTRIBUTE(nodiscard)
+#define LLVM_NODISCARD [[nodiscard]]
+#else
+#define LLVM_NODISCARD
+#endif
+
 // Indicate that a non-static, non-const C++ member function reinitializes
 // the entire object to a known state, independent of the previous state of
 // the object.
diff --git a/stdlib/private/CMakeLists.txt b/stdlib/private/CMakeLists.txt
index 5bb77689950b5..f6a78bef273eb 100644
--- a/stdlib/private/CMakeLists.txt
+++ b/stdlib/private/CMakeLists.txt
@@ -30,7 +30,10 @@ if(SWIFT_BUILD_SDK_OVERLAY
   endif()
   # Currently SwiftReflectionTest cannot be built on Windows, due to
   # dependencies on POSIX symbols
-  if (SWIFT_INCLUDE_TESTS AND (NOT CMAKE_SYSTEM_NAME STREQUAL "Windows"))
+  if (SWIFT_INCLUDE_TESTS
+      AND NOT CMAKE_SYSTEM_NAME STREQUAL "Windows"
+      AND NOT (CMAKE_SYSTEM_NAME STREQUAL "OpenBSD"
+               AND CMAKE_SYSTEM_VERSION VERSION_LESS "7.8"))
     add_subdirectory(SwiftReflectionTest)
   endif()
 endif()
diff --git a/stdlib/private/DifferentiationUnittest/DifferentiationUnittest.swift.gyb b/stdlib/private/DifferentiationUnittest/DifferentiationUnittest.swift.gyb
index c84b785d61d30..624a3c3a4afc4 100644
--- a/stdlib/private/DifferentiationUnittest/DifferentiationUnittest.swift.gyb
+++ b/stdlib/private/DifferentiationUnittest/DifferentiationUnittest.swift.gyb
@@ -340,6 +340,29 @@ where
   {
     return (lhs * rhs, { (dx, dy) in dx * rhs + dy * lhs })
   }
+
+  @usableFromInline
+  @derivative(of: *=)
+  static func _vjpMultiplyAssign(_ lhs: inout Self, _ rhs: Self) -> (
+    value: Void, pullback: (inout Self) -> Self)
+  {
+    defer { lhs *= rhs }
+    return ((), { [lhs = lhs] v in
+      let drhs = lhs * v
+      v *= rhs
+      return drhs
+    })
+  }
+
+  @usableFromInline
+  @derivative(of: *=)
+  static func _jvpMultiplyAssign(_ lhs: inout Self, _ rhs: Self) -> (
+    value: Void, differential: (inout Self, Self) -> Void)
+  {
+    let oldLhs = lhs
+    lhs *= rhs
+    return ((), { $0 = $0 * rhs + oldLhs * $1 })
+  }
 }
 
 extension ${Self}
diff --git a/stdlib/private/OSLog/CMakeLists.txt b/stdlib/private/OSLog/CMakeLists.txt
index befc43e172b7c..4941b39c89598 100644
--- a/stdlib/private/OSLog/CMakeLists.txt
+++ b/stdlib/private/OSLog/CMakeLists.txt
@@ -1,13 +1,18 @@
 set(swift_oslog_darwin_dependencies "")
-if(SWIFT_BUILD_SDK_OVERLAY)
-    list(APPEND swift_oslog_darwin_dependencies "Darwin")
-endif()
 if (SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY)
     list(APPEND swift_oslog_darwin_dependencies "_Concurrency")
 endif()
 if (SWIFT_ENABLE_EXPERIMENTAL_STRING_PROCESSING)
   list(APPEND swift_oslog_darwin_dependencies "_StringProcessing")
 endif()
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  # This library imports Darwin from the SDK, which re-exports
+  # _Builtin_float which is part of this build.
+  list(APPEND swift_oslog_darwin_dependencies _Builtin_float)
+endif()
 
 add_swift_target_library(swiftOSLogTestHelper
   IS_SDK_OVERLAY
diff --git a/stdlib/private/RuntimeUnittest/CMakeLists.txt b/stdlib/private/RuntimeUnittest/CMakeLists.txt
index 893bf08849166..0a5fbfacc73da 100644
--- a/stdlib/private/RuntimeUnittest/CMakeLists.txt
+++ b/stdlib/private/RuntimeUnittest/CMakeLists.txt
@@ -20,4 +20,11 @@ add_swift_target_library(swiftRuntimeUnittest ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES
   SWIFT_COMPILE_FLAGS ${swift_stdlib_unittest_compile_flags} ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   INSTALL_IN_COMPONENT stdlib-experimental
   DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}"
+
+  DEPLOYMENT_VERSION_OSX ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX}
+  DEPLOYMENT_VERSION_IOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}
+  DEPLOYMENT_VERSION_TVOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}
+  DEPLOYMENT_VERSION_WATCHOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}
+  DEPLOYMENT_VERSION_XROS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}
+
   MACCATALYST_BUILD_FLAVOR "zippered")
diff --git a/stdlib/private/StdlibCollectionUnittest/CMakeLists.txt b/stdlib/private/StdlibCollectionUnittest/CMakeLists.txt
index 6d0263a9155a7..e1727c9882125 100644
--- a/stdlib/private/StdlibCollectionUnittest/CMakeLists.txt
+++ b/stdlib/private/StdlibCollectionUnittest/CMakeLists.txt
@@ -27,6 +27,13 @@ add_swift_target_library(swiftStdlibCollectionUnittest ${SWIFT_STDLIB_LIBRARY_BU
   SWIFT_MODULE_DEPENDS_CYGWIN Glibc
   SWIFT_MODULE_DEPENDS_HAIKU Glibc
   SWIFT_MODULE_DEPENDS_WINDOWS CRT
+
+  DEPLOYMENT_VERSION_OSX ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX}
+  DEPLOYMENT_VERSION_IOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}
+  DEPLOYMENT_VERSION_TVOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}
+  DEPLOYMENT_VERSION_WATCHOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}
+  DEPLOYMENT_VERSION_XROS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}
+
   SWIFT_COMPILE_FLAGS ${swift_stdlib_unittest_compile_flags} ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   INSTALL_IN_COMPONENT stdlib-experimental
   DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}"
diff --git a/stdlib/private/StdlibUnicodeUnittest/CMakeLists.txt b/stdlib/private/StdlibUnicodeUnittest/CMakeLists.txt
index e1b11e436a832..e1a1eec87b67d 100644
--- a/stdlib/private/StdlibUnicodeUnittest/CMakeLists.txt
+++ b/stdlib/private/StdlibUnicodeUnittest/CMakeLists.txt
@@ -21,4 +21,11 @@ add_swift_target_library(swiftStdlibUnicodeUnittest ${SWIFT_STDLIB_LIBRARY_BUILD
   SWIFT_COMPILE_FLAGS ${swift_stdlib_unittest_compile_flags} ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   INSTALL_IN_COMPONENT stdlib-experimental
   DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}"
+
+  DEPLOYMENT_VERSION_OSX ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX}
+  DEPLOYMENT_VERSION_IOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}
+  DEPLOYMENT_VERSION_TVOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}
+  DEPLOYMENT_VERSION_WATCHOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}
+  DEPLOYMENT_VERSION_XROS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}
+
   MACCATALYST_BUILD_FLAVOR "zippered")
diff --git a/stdlib/private/StdlibUnittest/CMakeLists.txt b/stdlib/private/StdlibUnittest/CMakeLists.txt
index 5ebc25ecd3f72..6fee7d239c8bf 100644
--- a/stdlib/private/StdlibUnittest/CMakeLists.txt
+++ b/stdlib/private/StdlibUnittest/CMakeLists.txt
@@ -1,11 +1,19 @@
-if(SWIFT_BUILD_SDK_OVERLAY)
-set(swift_stdlib_unittest_darwin_dependencies Darwin)
-else()
 set(swift_stdlib_unittest_darwin_dependencies)
+
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  # This library imports Darwin from the SDK, which re-exports
+  # _Builtin_float which is part of this build.
+  list(APPEND swift_stdlib_unittest_darwin_dependencies _Builtin_float)
 endif()
 
 set(swift_stdlib_unittest_compile_flags
   "-Xfrontend" "-disable-objc-attr-requires-foundation-module")
+
+list(APPEND swift_stdlib_unittest_compile_flags "-enable-experimental-feature" "Lifetimes")
+
 if (SWIFT_RUNTIME_ENABLE_LEAK_CHECKER)
   list(APPEND swift_stdlib_unittest_compile_flags "-DSWIFT_RUNTIME_ENABLE_LEAK_CHECKER")
 endif()
@@ -71,6 +79,13 @@ add_swift_target_library(swiftStdlibUnittest ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES}
   SWIFT_MODULE_DEPENDS_HAIKU Glibc
   SWIFT_MODULE_DEPENDS_WASI WASILibc
   SWIFT_MODULE_DEPENDS_WINDOWS CRT WinSDK
+
+  DEPLOYMENT_VERSION_OSX ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX}
+  DEPLOYMENT_VERSION_IOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}
+  DEPLOYMENT_VERSION_TVOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}
+  DEPLOYMENT_VERSION_WATCHOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}
+  DEPLOYMENT_VERSION_XROS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}
+
   C_COMPILE_FLAGS -I${SWIFT_SOURCE_DIR}/stdlib/include
   SWIFT_COMPILE_FLAGS ${swift_stdlib_unittest_compile_flags} ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   INSTALL_IN_COMPONENT stdlib-experimental
diff --git a/stdlib/private/StdlibUnittest/StdlibUnittest.swift b/stdlib/private/StdlibUnittest/StdlibUnittest.swift
index 035a597cb62a2..681abf91fecd1 100644
--- a/stdlib/private/StdlibUnittest/StdlibUnittest.swift
+++ b/stdlib/private/StdlibUnittest/StdlibUnittest.swift
@@ -739,24 +739,46 @@ public func expectDoesNotThrow(_ test: () throws -> Void,
   }
 }
 
-public func expectNil<T>(_ value: T?,
+public func expectNil<T>(
+  _ value: T?,
   _ message: @autoclosure () -> String = "",
   stackTrace: SourceLocStack = SourceLocStack(),
   showFrame: Bool = true,
-  file: String = #file, line: UInt = #line) {
+  file: String = #file, line: UInt = #line
+) {
   if value != nil {
     expectationFailure(
-      "expected optional to be nil\nactual: \"\(value!)\"", trace: message(),
+      "expected optional to be nil\nactual: \"\(value!)\"",
+      trace: message(),
       stackTrace: stackTrace.pushIf(showFrame, file: file, line: line))
   }
 }
 
+public func expectNil<T: ~Copyable & ~Escapable>(
+  _ value: borrowing T?,
+  _ message: @autoclosure () -> String = "",
+  stackTrace: SourceLocStack = SourceLocStack(),
+  showFrame: Bool = true,
+  file: String = #file, line: UInt = #line
+) {
+  if value != nil {
+    expectationFailure(
+      "expected optional to be nil",
+      trace: message(),
+      stackTrace: stackTrace.pushIf(showFrame, file: file, line: line)
+    )
+  }
+}
+
 @discardableResult
-public func expectNotNil<T>(_ value: T?,
+@_lifetime(copy value)
+public func expectNotNil<T: ~Copyable & ~Escapable>(
+  _ value: consuming T?,
   _ message: @autoclosure () -> String = "",
   stackTrace: SourceLocStack = SourceLocStack(),
   showFrame: Bool = true,
-  file: String = #file, line: UInt = #line) -> T? {
+  file: String = #file, line: UInt = #line
+) -> T? {
   if value == nil {
     expectationFailure("expected optional to be non-nil", trace: message(),
       stackTrace: stackTrace.pushIf(showFrame, file: file, line: line))
@@ -1585,6 +1607,9 @@ class _ParentProcess {
         _testSuiteFailedCallback()
       } else {
         print("\(testSuite.name): All tests passed")
+        if testSuite._tests.isEmpty {
+          print("WARNING: SUITE '\(testSuite.name)' CONTAINED NO TESTS! NO TESTS WERE EXECUTED!")
+        }
       }
     }
     let (failed: failedOnShutdown, ()) = _shutdownChild()
diff --git a/stdlib/private/StdlibUnittestFoundationExtras/CMakeLists.txt b/stdlib/private/StdlibUnittestFoundationExtras/CMakeLists.txt
index ca3dd754ee9ef..2a9374a0b2160 100644
--- a/stdlib/private/StdlibUnittestFoundationExtras/CMakeLists.txt
+++ b/stdlib/private/StdlibUnittestFoundationExtras/CMakeLists.txt
@@ -7,5 +7,14 @@ add_swift_target_library(swiftStdlibUnittestFoundationExtras ${SWIFT_STDLIB_LIBR
   SWIFT_MODULE_DEPENDS StdlibUnittest
   SWIFT_COMPILE_FLAGS ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   INSTALL_IN_COMPONENT stdlib-experimental
-  DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}")
+  DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}"
+
+  DEPLOYMENT_VERSION_OSX ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX}
+  DEPLOYMENT_VERSION_IOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}
+  DEPLOYMENT_VERSION_TVOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}
+  DEPLOYMENT_VERSION_WATCHOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}
+  DEPLOYMENT_VERSION_XROS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}
+
+  MACCATALYST_BUILD_FLAVOR "zippered"
+)
 
diff --git a/stdlib/private/SwiftPrivate/CMakeLists.txt b/stdlib/private/SwiftPrivate/CMakeLists.txt
index 07b8ac7d0033c..bae0baaa60640 100644
--- a/stdlib/private/SwiftPrivate/CMakeLists.txt
+++ b/stdlib/private/SwiftPrivate/CMakeLists.txt
@@ -2,10 +2,15 @@ set(swift_swiftprivate_compile_flags
     "-parse-stdlib"
     "-Xfrontend" "-disable-access-control")
 
-if(SWIFT_BUILD_SDK_OVERLAY)
-set(swift_swiftprivate_darwin_dependencies Darwin)
-else()
 set(swift_swiftprivate_darwin_dependencies)
+
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  # This library imports Darwin from the SDK, which re-exports
+  # _Builtin_float which is part of this build.
+  list(APPEND swift_swiftprivate_darwin_dependencies _Builtin_float)
 endif()
 
 add_swift_target_library(swiftSwiftPrivate ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
@@ -36,6 +41,13 @@ add_swift_target_library(swiftSwiftPrivate ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} I
   SWIFT_MODULE_DEPENDS_HAIKU Glibc
   SWIFT_MODULE_DEPENDS_WASI WASILibc
   SWIFT_MODULE_DEPENDS_WINDOWS CRT WinSDK
+
+  DEPLOYMENT_VERSION_OSX ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX}
+  DEPLOYMENT_VERSION_IOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}
+  DEPLOYMENT_VERSION_TVOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}
+  DEPLOYMENT_VERSION_WATCHOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}
+  DEPLOYMENT_VERSION_XROS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}
+
   SWIFT_COMPILE_FLAGS ${swift_swiftprivate_compile_flags} ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   INSTALL_IN_COMPONENT stdlib-experimental
   DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}"
diff --git a/stdlib/private/SwiftPrivateLibcExtras/CMakeLists.txt b/stdlib/private/SwiftPrivateLibcExtras/CMakeLists.txt
index 83a13affb475d..4f222d96ee78e 100644
--- a/stdlib/private/SwiftPrivateLibcExtras/CMakeLists.txt
+++ b/stdlib/private/SwiftPrivateLibcExtras/CMakeLists.txt
@@ -14,10 +14,15 @@ else()
   set(swift_private_libc_extras_incorporate_object_libraries "swiftCommandLineSupport")
 endif()
 
-if(SWIFT_BUILD_SDK_OVERLAY)
-set(swift_private_libc_extras_darwin_dependencies Darwin)
-else()
 set(swift_private_libc_extras_darwin_dependencies)
+
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  # This library imports Darwin from the SDK, which re-exports
+  # _Builtin_float which is part of this build.
+  list(APPEND swift_private_libc_extras_darwin_dependencies _Builtin_float)
 endif()
 
 add_swift_target_library(swiftSwiftPrivateLibcExtras ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
@@ -47,6 +52,13 @@ add_swift_target_library(swiftSwiftPrivateLibcExtras ${SWIFT_STDLIB_LIBRARY_BUIL
   SWIFT_MODULE_DEPENDS_HAIKU Glibc
   SWIFT_MODULE_DEPENDS_WASI WASILibc
   SWIFT_MODULE_DEPENDS_WINDOWS CRT WinSDK
+
+  DEPLOYMENT_VERSION_OSX ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX}
+  DEPLOYMENT_VERSION_IOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}
+  DEPLOYMENT_VERSION_TVOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}
+  DEPLOYMENT_VERSION_WATCHOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}
+  DEPLOYMENT_VERSION_XROS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}
+
   INCORPORATE_OBJECT_LIBRARIES ${swift_private_libc_extras_incorporate_object_libraries}
   INSTALL_IN_COMPONENT stdlib-experimental
   DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}"
diff --git a/stdlib/private/SwiftPrivateThreadExtras/CMakeLists.txt b/stdlib/private/SwiftPrivateThreadExtras/CMakeLists.txt
index 124f162220585..ac13e2766c361 100644
--- a/stdlib/private/SwiftPrivateThreadExtras/CMakeLists.txt
+++ b/stdlib/private/SwiftPrivateThreadExtras/CMakeLists.txt
@@ -1,7 +1,12 @@
-if(SWIFT_BUILD_SDK_OVERLAY)
-set(swift_private_thread_extras_darwin_dependencies Darwin)
-else()
 set(swift_private_thread_extras_darwin_dependencies)
+
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  # This library imports Darwin from the SDK, which re-exports
+  # _Builtin_float which is part of this build.
+  list(APPEND swift_private_thread_extras_darwin_dependencies _Builtin_float)
 endif()
 
 add_swift_target_library(swiftSwiftPrivateThreadExtras ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
@@ -28,6 +33,13 @@ add_swift_target_library(swiftSwiftPrivateThreadExtras ${SWIFT_STDLIB_LIBRARY_BU
   SWIFT_MODULE_DEPENDS_HAIKU Glibc
   SWIFT_MODULE_DEPENDS_WASI WASILibc
   SWIFT_MODULE_DEPENDS_WINDOWS CRT WinSDK
+
+  DEPLOYMENT_VERSION_OSX ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX}
+  DEPLOYMENT_VERSION_IOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS}
+  DEPLOYMENT_VERSION_TVOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS}
+  DEPLOYMENT_VERSION_WATCHOS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS}
+  DEPLOYMENT_VERSION_XROS ${SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS}
+
   SWIFT_COMPILE_FLAGS ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   INSTALL_IN_COMPONENT stdlib-experimental
   DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}"
diff --git a/stdlib/private/SwiftReflectionTest/CMakeLists.txt b/stdlib/private/SwiftReflectionTest/CMakeLists.txt
index 6dba4e6ac07fb..8cbe7c8a6ee6d 100644
--- a/stdlib/private/SwiftReflectionTest/CMakeLists.txt
+++ b/stdlib/private/SwiftReflectionTest/CMakeLists.txt
@@ -1,7 +1,12 @@
-if(SWIFT_BUILD_SDK_OVERLAY)
-set(swift_reflection_test_darwin_dependencies Darwin)
-else()
 set(swift_reflection_test_darwin_dependencies)
+
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  # This library imports Darwin from the SDK, which re-exports
+  # _Builtin_float which is part of this build.
+  list(APPEND swift_reflection_test_darwin_dependencies _Builtin_float)
 endif()
 
 if (SWIFT_INCLUDE_TESTS AND SWIFT_BUILD_DYNAMIC_STDLIB)
diff --git a/stdlib/private/SwiftReflectionTest/SwiftReflectionTest.swift b/stdlib/private/SwiftReflectionTest/SwiftReflectionTest.swift
index f38adc5eb8ee7..5ba93bd7a67f0 100644
--- a/stdlib/private/SwiftReflectionTest/SwiftReflectionTest.swift
+++ b/stdlib/private/SwiftReflectionTest/SwiftReflectionTest.swift
@@ -32,6 +32,9 @@ let RequestPointerSize = "p"
 internal import MachO
 internal import Darwin
 internal import var Darwin.errno
+internal import var Darwin.stdout
+internal import var Darwin.stderr
+internal import var Darwin.stdin
 
 #if arch(x86_64) || arch(arm64)
 typealias MachHeader = mach_header_64
@@ -209,6 +212,7 @@ public enum InstanceKind: UInt8 {
   case Enum
   case EnumValue
   case AsyncTask
+  case LogString
 }
 
 /// Represents a section in a loaded image in this process.
@@ -642,6 +646,15 @@ public func reflect(asyncTask: UInt) {
   reflect(instanceAddress: asyncTask, kind: .AsyncTask)
 }
 
+/// Log a string to the test's output. Use instead of print, which gets
+/// captured by the parent and read as commands.
+public func reflectionLog(str: String) {
+  str.withCString {
+    let addr = UInt(bitPattern: $0)
+    reflect(instanceAddress: addr, kind: .LogString);
+  }
+}
+
 /// Call this function to indicate to the parent that there are
 /// no more instances to look at.
 public func doneReflecting() {
diff --git a/stdlib/public/ClangOverlays/CMakeLists.txt b/stdlib/public/ClangOverlays/CMakeLists.txt
index 5f399be8d52b7..5b91e00ccff98 100644
--- a/stdlib/public/ClangOverlays/CMakeLists.txt
+++ b/stdlib/public/ClangOverlays/CMakeLists.txt
@@ -1,4 +1,12 @@
 if(NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT)
+  set(BUILTIN_FLOAT_SOURCES
+    linker-support/magic-symbols-for-install-name.c
+  )
+
+  set(BUILTIN_FLOAT_GYB_SOURCES
+    float.swift.gyb
+  )
+
   if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
     set(BUILTIN_FLOAT_SWIFT_FLAGS -Xfrontend -module-abi-name -Xfrontend Darwin)
   else()
@@ -9,10 +17,10 @@ if(NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT OR NOT SWIFT_BUILD_
       ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES}
       IS_SDK_OVERLAY
       
-      linker-support/magic-symbols-for-install-name.c
+      ${BUILTIN_FLOAT_SOURCES}
 
       GYB_SOURCES
-        float.swift.gyb
+        ${BUILTIN_FLOAT_GYB_SOURCES}
 
       SWIFT_COMPILE_FLAGS
         ${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS}
@@ -24,4 +32,50 @@ if(NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT OR NOT SWIFT_BUILD_
 
       INSTALL_IN_COMPONENT stdlib
       MACCATALYST_BUILD_FLAVOR zippered)
+
+  # Embedded clang overlays - embedded libraries are built as .swiftmodule only,
+  # i.e. there is no .o or .a file produced (no binary code is actually produced)
+  # and only users of a library are going to actually compile any needed code.
+  if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
+    add_custom_target(embedded-builtin_float)
+    add_dependencies(embedded-libraries embedded-builtin_float)
+  
+    set(SWIFT_ENABLE_REFLECTION OFF)
+    set(SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT OFF)
+    set(SWIFT_STDLIB_STABLE_ABI OFF)
+    set(SWIFT_STDLIB_ENABLE_OBJC_INTEROP OFF)
+    set(SWIFT_STDLIB_ENABLE_VECTOR_TYPES OFF)
+
+    foreach(entry ${EMBEDDED_STDLIB_TARGET_TRIPLES})
+      string(REGEX REPLACE "[ \t]+" ";" list "${entry}")
+      list(GET list 0 arch)
+      list(GET list 1 mod)
+      list(GET list 2 triple)
+  
+      set(SWIFT_SDK_embedded_ARCH_${arch}_MODULE "${mod}")
+      set(SWIFT_SDK_embedded_LIB_SUBDIR "embedded")
+      set(SWIFT_SDK_embedded_ARCH_${arch}_TRIPLE "${triple}")
+      add_swift_target_library_single(
+        embedded-builtin_float-${mod}
+        swift_Builtin_float
+        ONLY_SWIFTMODULE
+        IS_FRAGILE
+        
+        ${BUILTIN_FLOAT_SOURCES}
+        GYB_SOURCES
+          ${BUILTIN_FLOAT_GYB_SOURCES}
+  
+        SWIFT_COMPILE_FLAGS
+          ${BUILTIN_FLOAT_SWIFT_FLAGS}
+          -Xcc -ffreestanding -enable-experimental-feature Embedded
+  
+        MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
+        SDK "embedded"
+        ARCHITECTURE "${arch}"
+        DEPENDS embedded-stdlib-${mod}
+        INSTALL_IN_COMPONENT stdlib
+        )
+      add_dependencies(embedded-builtin_float embedded-builtin_float-${mod})
+    endforeach()
+  endif()
 endif()
diff --git a/stdlib/public/ClangOverlays/float.swift.gyb b/stdlib/public/ClangOverlays/float.swift.gyb
index a285c7414393f..e99014898a584 100644
--- a/stdlib/public/ClangOverlays/float.swift.gyb
+++ b/stdlib/public/ClangOverlays/float.swift.gyb
@@ -18,7 +18,7 @@ public let FLT_RADIX = Double.radix
 
 %for type, prefix in [('Float', 'FLT'), ('Double', 'DBL'), ('Float80', 'LDBL')]:
 % if type == "Float80":
-#if !os(Android) && !os(WASI) && !os(Windows) && (arch(i386) || arch(x86_64))
+#if !os(Android) && !os(WASI) && !os(Windows) && !$Embedded && (arch(i386) || arch(x86_64))
 % end
 //  Where does the 1 come from? C counts the usually-implicit leading
 //  significand bit, but Swift does not. Neither is really right or wrong.
diff --git a/stdlib/public/CommandLineSupport/CommandLine.cpp b/stdlib/public/CommandLineSupport/CommandLine.cpp
index e1bc1e87df6bc..8ce32aca28a8e 100644
--- a/stdlib/public/CommandLineSupport/CommandLine.cpp
+++ b/stdlib/public/CommandLineSupport/CommandLine.cpp
@@ -37,6 +37,7 @@
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
 #include <shellapi.h>
+#pragma comment(lib, "shell32.lib")
 #endif
 
 // Backing storage for overrides of `Swift.CommandLine.arguments`.
@@ -135,7 +136,11 @@ char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
       }
     }
 
+#if defined(_WIN32)
+    argv[argc] = _strdup(arg);
+#else
     argv[argc] = strdup(arg);
+#endif
     argc += 1;
   });
 
diff --git a/stdlib/public/CompatibilityOverride/CompatibilityOverrideConcurrency.def b/stdlib/public/CompatibilityOverride/CompatibilityOverrideConcurrency.def
index 40cd713e4f629..7873272df2663 100644
--- a/stdlib/public/CompatibilityOverride/CompatibilityOverrideConcurrency.def
+++ b/stdlib/public/CompatibilityOverride/CompatibilityOverrideConcurrency.def
@@ -439,9 +439,10 @@ OVERRIDE_TASK(task_startOnMainActor, void,
               swift::, (AsyncTask *task), (task))
 
 // In ACTOR since we need ExecutorTracking info
-OVERRIDE_ACTOR(task_startSynchronously, void,
+OVERRIDE_ACTOR(task_immediate, void,
                SWIFT_EXPORT_FROM(swift_Concurrency), SWIFT_CC(swift),
-               swift::, (AsyncTask *task), (task))
+               swift::, (AsyncTask *task, SerialExecutorRef targetExecutor),
+               (task, targetExecutor))
 
 #undef OVERRIDE
 #undef OVERRIDE_ACTOR
diff --git a/stdlib/public/Concurrency/Actor.cpp b/stdlib/public/Concurrency/Actor.cpp
index 99f9dda006641..f3c7cd1ccdb13 100644
--- a/stdlib/public/Concurrency/Actor.cpp
+++ b/stdlib/public/Concurrency/Actor.cpp
@@ -256,8 +256,6 @@ void swift::runJobInEstablishedExecutorContext(Job *job) {
 #if SWIFT_OBJC_INTEROP
   objc_autoreleasePoolPop(pool);
 #endif
-
-  _swift_tsan_release(job);
 }
 
 void swift::adoptTaskVoucher(AsyncTask *task) {
@@ -410,9 +408,6 @@ static void _swift_task_debug_dumpIsCurrentExecutorFlags(
   if (options.contains(swift_task_is_current_executor_flag::Assert))
     SWIFT_TASK_DEBUG_LOG("%s swift_task_is_current_executor_flag::%s",
                          hint, "Assert");
-  if (options.contains(swift_task_is_current_executor_flag::UseIsIsolatingCurrentContext))
-    SWIFT_TASK_DEBUG_LOG("%s swift_task_is_current_executor_flag::%s",
-                         hint, "UseIsIsolatingCurrentContext");
 }
 
 // Shimming call to Swift runtime because Swift Embedded does not have
@@ -470,13 +465,6 @@ swift_task_is_current_executor_flag swift_bincompat_selectDefaultIsCurrentExecut
       // Remove the assert option which is what would cause the "crash" mode
       options = swift_task_is_current_executor_flag(
         options & ~swift_task_is_current_executor_flag::Assert);
-    } else if (strcmp(modeStr, "isIsolatingCurrentContext") == 0) {
-      options = swift_task_is_current_executor_flag(
-        options | swift_task_is_current_executor_flag::UseIsIsolatingCurrentContext);
-      // When we're using the isIsolatingCurrentContext we don't want to use crashing APIs,
-      // so disable it explicitly.
-      options = swift_task_is_current_executor_flag(
-        options & ~swift_task_is_current_executor_flag::Assert);
     } else if (strcmp(modeStr, "crash") == 0 ||
                strcmp(modeStr, "swift6") == 0) {
       options = swift_task_is_current_executor_flag(
@@ -497,41 +485,21 @@ extern "C" SWIFT_CC(swift) void _swift_task_enqueueOnTaskExecutor(
 // Implemented in Swift to avoid some annoying hard-coding about
 // SerialExecutor's protocol witness table.  We could inline this
 // with effort, though.
+#if SWIFT_CONCURRENCY_EMBEDDED
+extern "C" SWIFT_CC(swift) void _swift_task_enqueueOnExecutor(
+    Job *job, HeapObject *executor,
+    const SerialExecutorWitnessTable *wtable);
+#else
 extern "C" SWIFT_CC(swift) void _swift_task_enqueueOnExecutor(
     Job *job, HeapObject *executor, const Metadata *executorType,
     const SerialExecutorWitnessTable *wtable);
-
-/// Check the executor's witness table for specific information about e.g.
-/// being able ignore `checkIsolated` and only call `isIsolatingCurrentContext`.
-static swift_task_is_current_executor_flag
-_getIsolationCheckingOptionsFromExecutorWitnessTable(const SerialExecutorWitnessTable *_wtable) {
-  const WitnessTable* wtable = reinterpret_cast<const WitnessTable*>(_wtable);
-  auto description = wtable->getDescription();
-  if (!description) {
-    return swift_task_is_current_executor_flag::None;
-  }
-
-  if (description->hasNonDefaultSerialExecutorIsIsolatingCurrentContext()) {
-    // The specific executor has implemented `isIsolatingCurrentContext` and
-    // we do not have to call `checkIsolated`.
-    return swift_task_is_current_executor_flag::UseIsIsolatingCurrentContext;
-  }
-
-  // No changes to the checking mode.
-  return swift_task_is_current_executor_flag::None;
-}
+#endif // #if SWIFT_CONCURRENCY_EMBEDDED
 
 SWIFT_CC(swift)
 static bool swift_task_isCurrentExecutorWithFlagsImpl(
     SerialExecutorRef expectedExecutor,
     swift_task_is_current_executor_flag flags) {
   auto current = ExecutorTrackingInfo::current();
-  if (expectedExecutor.getIdentity() && expectedExecutor.hasSerialExecutorWitnessTable()) {
-    if (auto *wtable = expectedExecutor.getSerialExecutorWitnessTable()) {
-      auto executorSpecificMode = _getIsolationCheckingOptionsFromExecutorWitnessTable(wtable);
-      flags = swift_task_is_current_executor_flag(flags | executorSpecificMode);
-    }
-  }
 
   auto options = SwiftTaskIsCurrentExecutorOptions(flags);
   _swift_task_debug_dumpIsCurrentExecutorFlags(__FUNCTION__, flags);
@@ -551,16 +519,28 @@ static bool swift_task_isCurrentExecutorWithFlagsImpl(
     // We cannot use 'complexEquality' as it requires two executor instances,
     // and we do not have a 'current' executor here.
 
-    if (options.contains(swift_task_is_current_executor_flag::UseIsIsolatingCurrentContext)) {
-      SWIFT_TASK_DEBUG_LOG("executor checking mode option: UseIsIsolatingCurrentContext; invoke (%p).isIsolatingCurrentContext",
-                           expectedExecutor.getIdentity());
-      // The executor has the most recent 'isIsolatingCurrentContext' API
-      // so available so we prefer calling that to 'checkIsolated'.
-      auto result = swift_task_isIsolatingCurrentContext(expectedExecutor);
-
-      SWIFT_TASK_DEBUG_LOG("executor checking mode option: UseIsIsolatingCurrentContext; invoke (%p).isIsolatingCurrentContext => %s",
-                     expectedExecutor.getIdentity(), result ? "pass" : "fail");
-      return result;
+    // Invoke the 'isIsolatingCurrentContext', if "undecided" (i.e. nil), we need to make further calls
+    SWIFT_TASK_DEBUG_LOG("executor checking, invoke (%p).isIsolatingCurrentContext",
+                         expectedExecutor.getIdentity());
+    // The executor has the most recent 'isIsolatingCurrentContext' API
+    // so available so we prefer calling that to 'checkIsolated'.
+    auto isIsolatingCurrentContextDecision =
+        getIsIsolatingCurrentContextDecisionFromInt(
+            swift_task_isIsolatingCurrentContext(expectedExecutor));
+
+    SWIFT_TASK_DEBUG_LOG("executor checking mode option: UseIsIsolatingCurrentContext; invoke (%p).isIsolatingCurrentContext => %s",
+                   expectedExecutor.getIdentity(), getIsIsolatingCurrentContextDecisionNameStr(isIsolatingCurrentContextDecision));
+    switch (isIsolatingCurrentContextDecision) {
+      case IsIsolatingCurrentContextDecision::Isolated:
+        // We know for sure that this serial executor is isolating this context, return the decision.
+        return true;
+      case IsIsolatingCurrentContextDecision::NotIsolated:
+        // We know for sure that this serial executor is NOT isolating this context, return this decision.
+        return false;
+      case IsIsolatingCurrentContextDecision::Unknown:
+        // We don't know, so we have to continue trying to check using other methods.
+        // This most frequently would happen if a serial executor did not implement isIsolatingCurrentContext.
+        break;
     }
 
     // Otherwise, as last resort, let the expected executor check using
@@ -669,18 +649,21 @@ static bool swift_task_isCurrentExecutorWithFlagsImpl(
 
   // Invoke the 'isIsolatingCurrentContext' function if we can; If so, we can
   // avoid calling the `checkIsolated` because their result will be the same.
-  if (options.contains(swift_task_is_current_executor_flag::UseIsIsolatingCurrentContext)) {
-    SWIFT_TASK_DEBUG_LOG("executor checking: can call (%p).isIsolatingCurrentContext",
-      expectedExecutor.getIdentity());
+  SWIFT_TASK_DEBUG_LOG("executor checking: call (%p).isIsolatingCurrentContext",
+    expectedExecutor.getIdentity());
 
-    bool checkResult = swift_task_isIsolatingCurrentContext(expectedExecutor);
+  const auto isIsolatingCurrentContextDecision =
+    getIsIsolatingCurrentContextDecisionFromInt(swift_task_isIsolatingCurrentContext(expectedExecutor));
 
-    SWIFT_TASK_DEBUG_LOG("executor checking: can call (%p).isIsolatingCurrentContext => %p",
-      expectedExecutor.getIdentity(), checkResult ? "pass" : "fail");
-    return checkResult;
-  } else {
-    SWIFT_TASK_DEBUG_LOG("executor checking: can NOT call (%p).isIsolatingCurrentContext",
-                         expectedExecutor.getIdentity());
+  SWIFT_TASK_DEBUG_LOG("executor checking: can call (%p).isIsolatingCurrentContext => %p",
+    expectedExecutor.getIdentity(), getIsIsolatingCurrentContextDecisionNameStr(isIsolatingCurrentContextDecision));
+  switch (isIsolatingCurrentContextDecision) {
+  case IsIsolatingCurrentContextDecision::Isolated:
+    return true;
+  case IsIsolatingCurrentContextDecision::NotIsolated:
+    return false;
+  case IsIsolatingCurrentContextDecision::Unknown:
+    break;
   }
 
   // This provides a last-resort check by giving the expected SerialExecutor the
@@ -1161,8 +1144,8 @@ class alignas(sizeof(void *) * 2) ActiveActorStatus {
 #endif
   }
 
-  Job *getFirstUnprioritisedJob() const { return FirstJob; }
-  ActiveActorStatus withFirstUnprioritisedJob(Job *firstJob) const {
+  Job *getFirstUnprioritizedJob() const { return FirstJob; }
+  ActiveActorStatus withFirstUnprioritizedJob(Job *firstJob) const {
 #if SWIFT_CONCURRENCY_ENABLE_PRIORITY_ESCALATION
     return ActiveActorStatus(Flags, DrainLock, firstJob);
 #else
@@ -1207,7 +1190,7 @@ class alignas(sizeof(void *) * 2) ActiveActorStatus {
       break;
     }
     concurrency::trace::actor_state_changed(
-        actor, getFirstUnprioritisedJob(), traceState, distributedActorIsRemote,
+        actor, getFirstUnprioritizedJob(), traceState, distributedActorIsRemote,
         isMaxPriorityEscalated(), static_cast<uint8_t>(getMaxPriority()));
   }
 };
@@ -1391,7 +1374,7 @@ class DefaultActorImpl
   /// new priority
   void enqueueStealer(Job *job, JobPriority priority);
 
-  /// Dequeues one job from `prioritisedJobs`.
+  /// Dequeues one job from `prioritizedJobs`.
   /// The calling thread must be holding the actor lock while calling this
   Job *drainOne();
 
@@ -1580,9 +1563,9 @@ void DefaultActorImpl::enqueue(Job *job, JobPriority priority) {
     auto newState = oldState;
 
     // Link this into the queue in the atomic state
-    Job *currentHead = oldState.getFirstUnprioritisedJob();
+    Job *currentHead = oldState.getFirstUnprioritizedJob();
     setNextJob(job, currentHead);
-    newState = newState.withFirstUnprioritisedJob(job);
+    newState = newState.withFirstUnprioritizedJob(job);
 
     if (oldState.isIdle()) {
       // Schedule the actor
@@ -1763,13 +1746,13 @@ void DefaultActorImpl::processIncomingQueue() {
   while (true) {
     // If there aren't any new jobs in the incoming queue, we can return
     // immediately without updating the status.
-    if (!oldState.getFirstUnprioritisedJob()) {
+    if (!oldState.getFirstUnprioritizedJob()) {
       return;
     }
     assert(oldState.isAnyRunning());
 
     auto newState = oldState;
-    newState = newState.withFirstUnprioritisedJob(nullptr);
+    newState = newState.withFirstUnprioritizedJob(nullptr);
 
     if (_status().compare_exchange_weak(
             oldState, newState,
@@ -1782,7 +1765,7 @@ void DefaultActorImpl::processIncomingQueue() {
     }
   }
 
-  handleUnprioritizedJobs(oldState.getFirstUnprioritisedJob());
+  handleUnprioritizedJobs(oldState.getFirstUnprioritizedJob());
 }
 
 // Called with actor lock held on current thread
@@ -1950,7 +1933,7 @@ void DefaultActorImpl::destroy() {
   // Tasks on an actor are supposed to keep the actor alive until they start
   // running and we can only get here if ref count of the object = 0 which means
   // there should be no more tasks enqueued on the actor.
-  assert(!oldState.getFirstUnprioritisedJob() && "actor has queued jobs at destruction");
+  assert(!oldState.getFirstUnprioritizedJob() && "actor has queued jobs at destruction");
 
   if (oldState.isIdle()) {
     assert(prioritizedJobs.empty() && "actor has queued jobs at destruction");
@@ -2058,7 +2041,7 @@ retry:;
       }
 
       assert(oldState.getMaxPriority() == JobPriority::Unspecified);
-      assert(!oldState.getFirstUnprioritisedJob());
+      assert(!oldState.getFirstUnprioritizedJob());
       // We cannot assert here that prioritizedJobs is empty,
       // because lock is not held yet. Raise a flag to assert after getting the lock.
       assertNoJobs = true;
@@ -2077,7 +2060,7 @@ retry:;
     // check for higher priority jobs that could have been scheduled in the
     // meantime. And processing is more efficient when done in larger batches.
     if (asDrainer) {
-      newState = newState.withFirstUnprioritisedJob(nullptr);
+      newState = newState.withFirstUnprioritizedJob(nullptr);
     }
 
     // This needs an acquire since we are taking a lock
@@ -2090,7 +2073,7 @@ retry:;
       }
       traceActorStateTransition(this, oldState, newState, distributedActorIsRemote);
       if (asDrainer) {
-        handleUnprioritizedJobs(oldState.getFirstUnprioritisedJob());
+        handleUnprioritizedJobs(oldState.getFirstUnprioritizedJob());
       }
       return true;
     }
@@ -2141,7 +2124,7 @@ bool DefaultActorImpl::unlock(bool forceUnlock)
 
     auto newState = oldState;
     // Lock is still held at this point, so it is safe to access prioritizedJobs
-    if (!prioritizedJobs.empty() || oldState.getFirstUnprioritisedJob()) {
+    if (!prioritizedJobs.empty() || oldState.getFirstUnprioritizedJob()) {
       // There is work left to do, don't unlock the actor
       if (!forceUnlock) {
         SWIFT_TASK_DEBUG_LOG("Unlock-ing actor %p failed", this);
@@ -2414,13 +2397,15 @@ static bool mustSwitchToRun(SerialExecutorRef currentSerialExecutor,
   }
 
   // else, we may have to switch if the preferred task executor is different
-  auto differentTaskExecutor =
-      currentTaskExecutor.getIdentity() != newTaskExecutor.getIdentity();
-  if (differentTaskExecutor) {
-    return true;
-  }
+  if (currentTaskExecutor.getIdentity() == newTaskExecutor.getIdentity())
+    return false;
 
-  return false;
+  if (currentTaskExecutor.isUndefined())
+    currentTaskExecutor = swift_getDefaultExecutor();
+  if (newTaskExecutor.isUndefined())
+    newTaskExecutor = swift_getDefaultExecutor();
+
+  return currentTaskExecutor.getIdentity() != newTaskExecutor.getIdentity();
 }
 
 /// Given that we've assumed control of an executor on this thread,
@@ -2531,22 +2516,31 @@ static void swift_task_switchImpl(SWIFT_ASYNC_CONTEXT AsyncContext *resumeContex
 }
 
 SWIFT_CC(swift)
-static void swift_task_startSynchronouslyImpl(AsyncTask* task) {
+static void
+swift_task_immediateImpl(AsyncTask *task,
+                         SerialExecutorRef targetExecutor) {
   swift_retain(task);
-
-  auto currentTracking = ExecutorTrackingInfo::current();
-  if (currentTracking) {
-    auto currentExecutor = currentTracking->getActiveExecutor();
-    AsyncTask * originalTask = _swift_task_clearCurrent();
-
-    swift_job_run(task, currentExecutor);
-    _swift_task_setCurrent(originalTask);
+  if (targetExecutor.isGeneric()) {
+  // If the target is generic, it means that the closure did not specify
+  // an isolation explicitly. According to the "start synchronously" rules,
+  // we should therefore ignore the global and just start running on the
+  // caller immediately.
+  SerialExecutorRef executor = SerialExecutorRef::forSynchronousStart();
+
+  auto originalTask = ActiveTask::swap(task);
+  swift_job_run(task, executor);
+  _swift_task_setCurrent(originalTask);
   } else {
-    auto originalTask = ActiveTask::swap(task);
-    assert(!originalTask);
+    assert(swift_task_isCurrentExecutor(targetExecutor) &&
+           "'immediate' must only be invoked when it is correctly in "
+           "the same isolation already, but wasn't!");
+
+    // We can run synchronously, we're on the expected executor so running in
+    // the caller context is going to be in the same context as the requested
+    // "caller" context.
+    AsyncTask *originalTask = _swift_task_clearCurrent();
 
-    SerialExecutorRef executor = SerialExecutorRef::forSynchronousStart();
-     swift_job_run(task, executor);
+    swift_job_run(task, targetExecutor);
     _swift_task_setCurrent(originalTask);
   }
 }
@@ -2588,7 +2582,7 @@ static void swift_task_deinitOnExecutorImpl(void *object,
                                             SerialExecutorRef newExecutor,
                                             size_t rawFlags) {
   // Sign the function pointer
-  work = swift_auth_code_function(
+  work = swift_auth_code(
       work, SpecialPointerAuthDiscriminators::DeinitWorkFunction);
   // If the current executor is compatible with running the new executor,
   // we can just immediately continue running with the resume function
@@ -2716,7 +2710,11 @@ static void swift_task_enqueueImpl(Job *job, SerialExecutorRef serialExecutorRef
     return swift_defaultActor_enqueue(job, serialExecutorRef.getDefaultActor());
   }
 
-#if SWIFT_CONCURRENCY_EMBEDDED
+#if SWIFT_CONCURRENCY_EMBEDDED && defined(__wasi__)
+  auto serialExecutorIdentity = serialExecutorRef.getIdentity();
+  auto serialExecutorWtable = serialExecutorRef.getSerialExecutorWitnessTable();
+  _swift_task_enqueueOnExecutor(job, serialExecutorIdentity, serialExecutorWtable);
+#elif SWIFT_CONCURRENCY_EMBEDDED
   swift_unreachable("custom executors not supported in embedded Swift");
 #else
   // For main actor or actors with custom executors
diff --git a/stdlib/public/Concurrency/Actor.swift b/stdlib/public/Concurrency/Actor.swift
index c72fa895a7622..7eea4bd926b7a 100644
--- a/stdlib/public/Concurrency/Actor.swift
+++ b/stdlib/public/Concurrency/Actor.swift
@@ -99,41 +99,12 @@ internal func _enqueueOnMain(_ job: UnownedJob)
 @freestanding(expression)
 public macro isolation<T>() -> T = Builtin.IsolationMacro
 
-/// Wrap the function body in a new top-level task on behalf of the
-/// given actor.
-@available(SwiftStdlib 5.1, *)
-@attached(body)
-public macro Task(
-  on actor: any GlobalActor,
-  name: String? = nil,
-  priority: TaskPriority? = nil
-) =
-  #externalMacro(module: "SwiftMacros", type: "TaskMacro")
-
-/// Wrap the function body in a new top-level task on behalf of the
-/// current actor.
-@available(SwiftStdlib 5.1, *)
-@attached(body)
-public macro Task(
-  name: String? = nil,
-  priority: TaskPriority? = nil
-) =
-  #externalMacro(module: "SwiftMacros", type: "TaskMacro")
-
-// NOTE: We put SwiftSetting under $Macro since #SwiftSettings() is a macro.
-@available(SwiftStdlib 9999, *)
-extension SwiftSetting {
-  /// Force the current module to use the passed in defaultIsolation instead of
-  /// the default isolation.
-  @available(SwiftStdlib 9999, *)
-  public static func defaultIsolation(_ actor: Actor.Type?) -> SwiftSetting { SwiftSetting() }
-}
-
 #endif
 
 #if $IsolatedAny
 @_alwaysEmitIntoClient
 @available(SwiftStdlib 5.1, *)
+@available(*, deprecated, message: "Use `.isolation` on @isolated(any) closure values instead.")
 public func extractIsolation<each Arg, Result>(
   _ fn: @escaping @isolated(any) (repeat each Arg) async throws -> Result
 ) -> (any Actor)? {
diff --git a/stdlib/public/Concurrency/AsyncLet.cpp b/stdlib/public/Concurrency/AsyncLet.cpp
index 7764eb17df432..b95a2756de5ee 100644
--- a/stdlib/public/Concurrency/AsyncLet.cpp
+++ b/stdlib/public/Concurrency/AsyncLet.cpp
@@ -24,9 +24,9 @@
 #include "swift/ABI/Metadata.h"
 #include "swift/ABI/Task.h"
 #include "swift/ABI/TaskOptions.h"
+#include "swift/Basic/Casting.h"
 #include "swift/Runtime/Heap.h"
 #include "swift/Runtime/HeapObject.h"
-#include "swift/Runtime/STLCompatibility.h"
 #include "swift/Threading/Mutex.h"
 #include "llvm/ADT/PointerIntPair.h"
 
@@ -289,7 +289,7 @@ static void _asyncLet_get_throwing_continuation(
 
   // Continue the caller's execution.
   auto throwingResume =
-      std::bit_cast<ThrowingTaskFutureWaitContinuationFunction*>(callContext->ResumeParent);
+      function_cast<ThrowingTaskFutureWaitContinuationFunction*>(callContext->ResumeParent);
   return throwingResume(callContext->Parent, error);
 }
 
@@ -307,7 +307,7 @@ static void swift_asyncLet_get_throwingImpl(
 
   auto aletContext = static_cast<AsyncLetContinuationContext*>(callContext);
   aletContext->ResumeParent =
-      std::bit_cast<TaskContinuationFunction*>(resumeFunction);
+      function_cast<TaskContinuationFunction*>(resumeFunction);
   aletContext->Parent = callerContext;
   aletContext->alet = alet;
   auto futureContext = asImpl(alet)->getFutureContext();
@@ -377,7 +377,7 @@ static void asyncLet_finish_after_task_completion(SWIFT_ASYNC_CONTEXT AsyncConte
     swift_task_dealloc(task);
   }
 
-  return std::bit_cast<ThrowingTaskFutureWaitContinuationFunction*>(resumeFunction)
+  return function_cast<ThrowingTaskFutureWaitContinuationFunction*>(resumeFunction)
     (callerContext, error);
 }
 
@@ -529,14 +529,14 @@ static void swift_asyncLet_consume_throwingImpl(
   if (asImpl(alet)->hasResultInBuffer()) {
     return asyncLet_finish_after_task_completion(callerContext,
                    alet,
-                   std::bit_cast<TaskContinuationFunction*>(resumeFunction),
+                   function_cast<TaskContinuationFunction*>(resumeFunction),
                    callContext,
                    nullptr);
   }
 
   auto aletContext = static_cast<AsyncLetContinuationContext*>(callContext);
   aletContext->ResumeParent =
-      std::bit_cast<TaskContinuationFunction*>(resumeFunction);
+      function_cast<TaskContinuationFunction*>(resumeFunction);
   aletContext->Parent = callerContext;
   aletContext->alet = alet;
   auto futureContext = asImpl(alet)->getFutureContext();
diff --git a/stdlib/public/Concurrency/AsyncStream.swift b/stdlib/public/Concurrency/AsyncStream.swift
index d678246efc7e7..ca6eb979695c1 100644
--- a/stdlib/public/Concurrency/AsyncStream.swift
+++ b/stdlib/public/Concurrency/AsyncStream.swift
@@ -475,6 +475,22 @@ extension AsyncStream: @unchecked Sendable where Element: Sendable { }
 @available(SwiftStdlib 5.1, *)
 extension AsyncStream.Continuation.YieldResult: Sendable where Element: Sendable { }
 
+@available(SwiftStdlib 6.2, *)
+extension AsyncStream.Continuation: Hashable {
+  @available(SwiftStdlib 6.2, *)
+  public func hash(into hasher: inout Hasher) {
+    return hasher.combine(ObjectIdentifier(storage))
+  }
+  @available(SwiftStdlib 6.2, *)
+  public var hashValue: Int {
+    return _hashValue(for: self)
+  }
+  @available(SwiftStdlib 6.2, *)
+  public static func == (lhs: Self, rhs: Self) -> Bool {
+    return lhs.storage === rhs.storage
+  }
+}
+
 #else
 @available(SwiftStdlib 5.1, *)
 @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
diff --git a/stdlib/public/Concurrency/AsyncThrowingStream.swift b/stdlib/public/Concurrency/AsyncThrowingStream.swift
index 488ff9760f38d..3cdc5d0077bf0 100644
--- a/stdlib/public/Concurrency/AsyncThrowingStream.swift
+++ b/stdlib/public/Concurrency/AsyncThrowingStream.swift
@@ -521,6 +521,22 @@ extension AsyncThrowingStream: @unchecked Sendable where Element: Sendable { }
 @available(SwiftStdlib 5.1, *)
 extension AsyncThrowingStream.Continuation.YieldResult: Sendable where Element: Sendable { }
 
+@available(SwiftStdlib 6.2, *)
+extension AsyncThrowingStream.Continuation: Hashable {
+  @available(SwiftStdlib 6.2, *)
+  public func hash(into hasher: inout Hasher) {
+    return hasher.combine(ObjectIdentifier(storage))
+  }
+  @available(SwiftStdlib 6.2, *)
+  public var hashValue: Int {
+    return _hashValue(for: self)
+  }
+  @available(SwiftStdlib 6.2, *)
+  public static func == (lhs: Self, rhs: Self) -> Bool {
+    return lhs.storage === rhs.storage
+  }
+}
+
 #else
 @available(SwiftStdlib 5.1, *)
 @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
diff --git a/stdlib/public/Concurrency/CFExecutor.cpp b/stdlib/public/Concurrency/CFExecutor.cpp
new file mode 100644
index 0000000000000..b93979a62f486
--- /dev/null
+++ b/stdlib/public/Concurrency/CFExecutor.cpp
@@ -0,0 +1,25 @@
+//===--- CFExecutor.cpp ----------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+#include "swift/Runtime/Concurrency.h"
+#include <dlfcn.h>
+
+using namespace swift;
+
+SWIFT_CC(swift)
+extern "C" void * _swift_concurrency_dlopen_noload(const char * __path) {
+  return dlopen( __path, RTLD_NOLOAD);
+}
+
+SWIFT_CC(swift)
+extern "C" void * _swift_concurrency_dlsym(void * __handle, const char * __symbol) {
+  return dlsym(__handle, __symbol);
+}
diff --git a/stdlib/public/Concurrency/CFExecutor.swift b/stdlib/public/Concurrency/CFExecutor.swift
index 451e0860e7975..bc78d3175c60a 100644
--- a/stdlib/public/Concurrency/CFExecutor.swift
+++ b/stdlib/public/Concurrency/CFExecutor.swift
@@ -14,7 +14,11 @@
 
 import Swift
 
-internal import Darwin
+@_silgen_name("_swift_concurrency_dlopen_noload")
+private func dlopen_noload(_ path: UnsafePointer<CChar>?) -> OpaquePointer?
+
+@_silgen_name("_swift_concurrency_dlsym")
+private func dlsym(_ handle: OpaquePointer?, _ symbol: UnsafePointer<CChar>?) -> OpaquePointer?
 
 // .. Dynamic binding ..........................................................
 
@@ -22,7 +26,7 @@ enum CoreFoundation {
   static let path =
     "/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation"
 
-  static let handle = unsafe dlopen(path, RTLD_NOLOAD)
+  static let handle = unsafe dlopen_noload(path)
 
   static var isPresent: Bool { return unsafe handle != nil }
 
@@ -43,8 +47,9 @@ enum CoreFoundation {
 
 // .. Main Executor ............................................................
 
-@available(SwiftStdlib 6.2, *)
-public final class CFMainExecutor: DispatchMainExecutor, @unchecked Sendable {
+/// A CFRunLoop-based main executor (Apple platforms only)
+@available(StdlibDeploymentTarget 6.2, *)
+final class CFMainExecutor: DispatchMainExecutor, @unchecked Sendable {
 
   override public func run() throws {
     CoreFoundation.CFRunLoopRun()
@@ -58,9 +63,10 @@ public final class CFMainExecutor: DispatchMainExecutor, @unchecked Sendable {
 
 // .. Task Executor ............................................................
 
-@available(SwiftStdlib 6.2, *)
-public final class CFTaskExecutor: DispatchGlobalTaskExecutor,
-                                   @unchecked Sendable {
+/// A `TaskExecutor` to match `CFMainExecutor` (Apple platforms only)
+@available(StdlibDeploymentTarget 6.2, *)
+final class CFTaskExecutor: DispatchGlobalTaskExecutor,
+                            @unchecked Sendable {
 
 }
 
diff --git a/stdlib/public/Concurrency/CMakeLists.txt b/stdlib/public/Concurrency/CMakeLists.txt
index ef4d0d51451d8..d2e82536ddcbd 100644
--- a/stdlib/public/Concurrency/CMakeLists.txt
+++ b/stdlib/public/Concurrency/CMakeLists.txt
@@ -66,6 +66,9 @@ list(APPEND SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS
   )
 
 list(APPEND SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS "-strict-memory-safety")
+list(APPEND SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS "-enable-experimental-feature" "AllowUnsafeAttribute")
+
+list(APPEND SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS "-enable-experimental-feature" "Extern")
 
 list(APPEND SWIFT_RUNTIME_CONCURRENCY_C_FLAGS
   "-D__STDC_WANT_LIB_EXT1__=1")
@@ -75,13 +78,12 @@ set(SWIFT_RUNTIME_CONCURRENCY_C_SOURCES
   Actor.cpp
   AsyncLet.cpp
   Clock.cpp
-  GlobalExecutor.cpp
   ConcurrencyHooks.cpp
+  GlobalExecutor.cpp
   EmbeddedSupport.cpp
   Error.cpp
   ExecutorBridge.cpp
   ExecutorChecks.cpp
-  Setup.cpp
   Task.cpp
   TaskAlloc.cpp
   TaskStatus.cpp
@@ -128,7 +130,6 @@ set(SWIFT_RUNTIME_CONCURRENCY_SWIFT_SOURCES
   Task+TaskExecutor.swift
   TaskCancellation.swift
   TaskGroup.swift
-  TaskGroup+Embedded.swift
   DiscardingTaskGroup.swift
   TaskLocal.swift
   TaskSleep.swift
@@ -158,15 +159,22 @@ set(SWIFT_RUNTIME_CONCURRENCY_SWIFT_SOURCES
   ContinuousClock.swift
   SuspendingClock.swift
   TaskSleepDuration.swift
-  DummyExecutor.swift
+  UnimplementedExecutor.swift
   CooperativeExecutor.swift
   PlatformExecutorDarwin.swift
   PlatformExecutorLinux.swift
   PlatformExecutorWindows.swift
+  PlatformExecutorOpenBSD.swift
+  PlatformExecutorFreeBSD.swift
+)
+
+set(SWIFT_RUNTIME_CONCURRENCY_NONEMBEDDED_C_SOURCES
+  ExecutorImpl.cpp
 )
 
 set(SWIFT_RUNTIME_CONCURRENCY_EXECUTOR_SOURCES)
 set(SWIFT_RUNTIME_CONCURRENCY_NONEMBEDDED_SWIFT_SOURCES)
+
 if("${SWIFT_CONCURRENCY_GLOBAL_EXECUTOR}" STREQUAL "dispatch")
   set(SWIFT_RUNTIME_CONCURRENCY_EXECUTOR_SOURCES
     DispatchGlobalExecutor.cpp
@@ -176,6 +184,9 @@ if("${SWIFT_CONCURRENCY_GLOBAL_EXECUTOR}" STREQUAL "dispatch")
     CFExecutor.swift
     ExecutorImpl.swift
   )
+  if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
+    list(APPEND SWIFT_RUNTIME_CONCURRENCY_NONEMBEDDED_C_SOURCES CFExecutor.cpp)
+  endif()
 elseif("${SWIFT_CONCURRENCY_GLOBAL_EXECUTOR}" STREQUAL "singlethreaded")
   set(SWIFT_RUNTIME_CONCURRENCY_NONEMBEDDED_SWIFT_SOURCES
     ExecutorImpl.swift
@@ -188,26 +199,43 @@ else()
   )
 endif()
 
-set(SWIFT_RUNTIME_CONCURRENCY_EMBEDDED_SWIFT_SOURCES
-  PlatformExecutorNone.swift
-  )
-
 set(LLVM_OPTIONAL_SOURCES
   DispatchGlobalExecutor.cpp
   CooperativeGlobalExecutor.cpp
   DispatchGlobalExecutor.cpp
+  CFExecutor.cpp
 )
 
+set(SWIFT_CONCURRENCY_DEPENDENCIES)
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  set(SWIFT_CONCURRENCY_DEPENDENCIES _Builtin_float)
+endif()
+set(SWIFT_CONCURRENCY_GYB_SOURCES
+  Task+init.swift.gyb
+  TaskGroup+addTask.swift.gyb
+  Task+immediate.swift.gyb)
+
+# Build with a minimum deployment target of 10.15
+if(SWIFT_DARWIN_DEPLOYMENT_VERSION_OSX VERSION_LESS "10.15")
+  set(osx_deployment_target "10.15")
+else()
+  set(osx_deployment_target "${SWIFT_DARWIN_DEPLOYMENT_VERSION_OSX}")
+endif()
+
 add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   ${SWIFT_RUNTIME_CONCURRENCY_C_SOURCES}
   ${SWIFT_RUNTIME_CONCURRENCY_EXECUTOR_SOURCES}
+  ${SWIFT_RUNTIME_CONCURRENCY_NONEMBEDDED_C_SOURCES}
   ${SWIFT_RUNTIME_CONCURRENCY_SWIFT_SOURCES}
   ${SWIFT_RUNTIME_CONCURRENCY_NONEMBEDDED_SWIFT_SOURCES}
 
   GYB_SOURCES
-    TaskGroup+addTask.swift.gyb
-    Task+startSynchronously.swift.gyb
+    ${SWIFT_CONCURRENCY_GYB_SOURCES}
 
+  SWIFT_MODULE_DEPENDS ${SWIFT_CONCURRENCY_DEPENDENCIES}
   SWIFT_MODULE_DEPENDS_ANDROID Android
   SWIFT_MODULE_DEPENDS_LINUX Glibc
   SWIFT_MODULE_DEPENDS_LINUX_STATIC Musl
@@ -222,6 +250,8 @@ add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} I
     ${swift_concurrency_incorporate_object_libraries_so}
   LINK_LIBRARIES ${swift_concurrency_link_libraries}
 
+  DEPLOYMENT_VERSION_OSX ${osx_deployment_target}
+
   C_COMPILE_FLAGS
     -Dswift_Concurrency_EXPORTS ${SWIFT_RUNTIME_CONCURRENCY_C_FLAGS}
     -I${SWIFT_SOURCE_DIR}/stdlib/include
@@ -258,6 +288,7 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB AND SWIFT_SHOULD_BUILD_EMBEDDED_CONCURRENC
   set(SWIFT_STDLIB_CONCURRENCY_TRACING FALSE)
   set(SWIFT_STDLIB_HAS_ENVIRON FALSE)
   set(SWIFT_STDLIB_HAS_ASL FALSE)
+  list(APPEND LLVM_OPTIONAL_SOURCES ExecutorImpl.cpp)
 
   foreach(entry ${EMBEDDED_STDLIB_TARGET_TRIPLES})
     string(REGEX REPLACE "[ \t]+" ";" list "${entry}")
@@ -265,36 +296,44 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB AND SWIFT_SHOULD_BUILD_EMBEDDED_CONCURRENC
     list(GET list 1 mod)
     list(GET list 2 triple)
 
+    set(extra_c_compile_flags)
+    set(extra_swift_compile_flags)
+
     if (SWIFT_HOST_VARIANT STREQUAL "linux")
       if(NOT "${mod}" MATCHES "-linux-gnu$")
         continue()
       endif()
-      set(extra_c_compile_flags)
-      set(extra_swift_compile_flags)
     elseif (SWIFT_HOST_VARIANT STREQUAL "macosx")
-      if(NOT "${mod}" MATCHES "-macos$")
-        continue()
-      endif()
-      if("${mod}" MATCHES "riscv")
-        continue()
-      endif()
-      if("${mod}" MATCHES "armv6m")
+      if(NOT "${mod}" MATCHES "x86_64|arm64|arm64e|armv7|armv7m|armv7em")
         continue()
       endif()
 
-      if("${mod}" MATCHES "-macos$")
-        set(extra_c_compile_flags -ffreestanding -stdlib=libc++)
-        set(extra_swift_compile_flags -Xcc -ffreestanding)
+      if(NOT "${mod}" MATCHES "-apple-" OR "${mod}" MATCHES "-none-macho" OR "${arch}" STREQUAL "armv7m" OR "${arch}" STREQUAL "armv7em")
+        # Host is macOS with a macOS SDK. To be able to build the C++ Concurrency runtime for non-Darwin targets using the macOS SDK,
+        # we need to pass some extra flags and search paths.
+        set(extra_c_compile_flags -stdlib=libc++ -isystem${SWIFT_SDK_OSX_PATH}/usr/include/c++/v1 -isystem${SWIFT_SDK_OSX_PATH}/usr/include -D__APPLE__)
       endif()
+    endif()
 
-    elseif (SWIFT_HOST_VARIANT STREQUAL "wasi")
-      set(extra_c_compile_flags)
-      set(extra_swift_compile_flags)
+    if("${arch}" MATCHES "wasm32")
+      set(SWIFT_RUNTIME_CONCURRENCY_EMBEDDED_SWIFT_SOURCES
+        ExecutorImpl.swift
+        PlatformExecutorCooperative.swift
+      )
+      list(APPEND SWIFT_RUNTIME_CONCURRENCY_C_SOURCES
+        ExecutorImpl.cpp
+      )
+    else()
+      set(SWIFT_RUNTIME_CONCURRENCY_EMBEDDED_SWIFT_SOURCES
+        PlatformExecutorNone.swift
+      )
     endif()
 
     set(SWIFT_SDK_embedded_THREADING_PACKAGE none)
+    set(SWIFT_SDK_embedded_ARCH_${arch}_MODULE "${mod}")
     set(SWIFT_SDK_embedded_ARCH_${mod}_MODULE "${mod}")
     set(SWIFT_SDK_embedded_LIB_SUBDIR "embedded")
+    set(SWIFT_SDK_embedded_ARCH_${arch}_TRIPLE "${triple}")
     set(SWIFT_SDK_embedded_ARCH_${mod}_TRIPLE "${triple}")
 
     # lib/swift/embedded/_Concurrency.swiftmodule
@@ -309,6 +348,9 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB AND SWIFT_SHOULD_BUILD_EMBEDDED_CONCURRENC
       ${SWIFT_RUNTIME_CONCURRENCY_SWIFT_SOURCES}
       ${SWIFT_RUNTIME_CONCURRENCY_EMBEDDED_SWIFT_SOURCES}
 
+      GYB_SOURCES
+        ${SWIFT_CONCURRENCY_GYB_SOURCES}
+
       SWIFT_COMPILE_FLAGS
         ${extra_swift_compile_flags} -enable-experimental-feature Embedded
         -parse-stdlib -DSWIFT_CONCURRENCY_EMBEDDED
@@ -316,9 +358,11 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB AND SWIFT_SHOULD_BUILD_EMBEDDED_CONCURRENC
         ${SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS}
       C_COMPILE_FLAGS
         ${extra_c_compile_flags} ${SWIFT_RUNTIME_CONCURRENCY_C_FLAGS} -DSWIFT_CONCURRENCY_EMBEDDED=1 -DSWIFT_RUNTIME_EMBEDDED=1
+        -ffunction-sections -fdata-sections -fno-exceptions -fno-cxx-exceptions -fno-unwind-tables
       MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
       SDK "embedded"
-      ARCHITECTURE "${mod}"
+      ARCHITECTURE "${arch}"
+      ARCHITECTURE_SUBDIR_NAME "${mod}"
       DEPENDS embedded-stdlib-${mod}
       INSTALL_IN_COMPONENT stdlib
       )
diff --git a/stdlib/public/Concurrency/Clock.cpp b/stdlib/public/Concurrency/Clock.cpp
index 0ae357a5ddad5..fd51110d47302 100644
--- a/stdlib/public/Concurrency/Clock.cpp
+++ b/stdlib/public/Concurrency/Clock.cpp
@@ -33,6 +33,10 @@
 
 #include "Error.h"
 
+#ifndef NSEC_PER_SEC
+#define NSEC_PER_SEC 1000000000ull
+#endif
+
 using namespace swift;
 
 SWIFT_EXPORT_FROM(swift_Concurrency)
@@ -109,6 +113,29 @@ void swift_get_time(
       *seconds = suspending.tv_sec;
       *nanoseconds = suspending.tv_nsec;
       return;
+    case swift_clock_id_wall:
+      struct timespec wall;
+#if defined(__linux__) || defined(__APPLE__) || defined(__wasi__) || defined(__OpenBSD__) || defined(__FreeBSD__)
+      clock_gettime(CLOCK_REALTIME, &wall);
+#elif defined(_WIN32)
+      // This needs to match what swift-corelibs-libdispatch does
+
+      static const uint64_t kNTToUNIXBiasAdjustment = 11644473600 * NSEC_PER_SEC;
+      // FILETIME is 100-nanosecond intervals since January 1, 1601 (UTC).
+      FILETIME ft;
+      ULARGE_INTEGER li;
+      GetSystemTimePreciseAsFileTime(&ft);
+      li.LowPart = ft.dwLowDateTime;
+      li.HighPart = ft.dwHighDateTime;
+      ULONGLONG ns = li.QuadPart * 100ull - kNTToUNIXBiasAdjustment;
+      wall.tv_sec = ns / 1000000000ull;
+      wall.tv_nsec = ns % 1000000000ull;
+#else
+#error Missing platform wall time definition
+#endif
+      *seconds = wall.tv_sec;
+      *nanoseconds = wall.tv_nsec;
+      return;
     }
   }
   swift_Concurrency_fatalError(0, "Fatal error: invalid clock ID %d\n",
@@ -170,6 +197,20 @@ switch (clock_id) {
       *nanoseconds = suspending.tv_nsec;
       return;
     }
+    case swift_clock_id_wall: {
+      struct timespec wall;
+#if defined(__linux__) || defined(__APPLE__) || defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__wasi__)
+      clock_getres(CLOCK_REALTIME, &wall);
+#elif defined(_WIN32)
+      wall.tv_sec = 0;
+      wall.tv_nsec = 100;
+#else
+#error Missing platform wall time definition
+#endif
+      *seconds = wall.tv_sec;
+      *nanoseconds = wall.tv_nsec;
+      return;
+    }
   }
   swift_Concurrency_fatalError(0, "Fatal error: invalid clock ID %d\n",
                                clock_id);
diff --git a/stdlib/public/Concurrency/Clock.swift b/stdlib/public/Concurrency/Clock.swift
index 8c6864ca3447c..dd38cbcbadbe0 100644
--- a/stdlib/public/Concurrency/Clock.swift
+++ b/stdlib/public/Concurrency/Clock.swift
@@ -30,7 +30,7 @@ import Swift
 ///
 /// For more information about specific clocks see `ContinuousClock` and
 /// `SuspendingClock`.
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 public protocol Clock<Duration>: Sendable {
   associatedtype Duration
   associatedtype Instant: InstantProtocol where Instant.Duration == Duration
@@ -40,54 +40,66 @@ public protocol Clock<Duration>: Sendable {
 
 #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
   func sleep(until deadline: Instant, tolerance: Instant.Duration?) async throws
-#endif
-
-  /// The traits associated with this clock instance.
-  @available(SwiftStdlib 6.2, *)
-  var traits: ClockTraits { get }
 
-  /// Convert a Clock-specific Duration to a Swift Duration
-  ///
-  /// Some clocks may define `C.Duration` to be something other than a
-  /// `Swift.Duration`, but that makes it tricky to convert timestamps
-  /// between clocks, which is something we want to be able to support.
-  /// This method will convert whatever `C.Duration` is to a `Swift.Duration`.
+  /// Run the given job on an unspecified executor at some point
+  /// after the given instant.
   ///
   /// Parameters:
   ///
-  /// - from duration: The `Duration` to convert
+  /// - job:         The job we wish to run
+  /// - at instant:  The time at which we would like it to run.
+  /// - tolerance:   The ideal maximum delay we are willing to tolerate.
   ///
-  /// Returns: A `Swift.Duration` representing the equivalent duration, or
-  ///          `nil` if this function is not supported.
-  @available(SwiftStdlib 6.2, *)
-  func convert(from duration: Duration) -> Swift.Duration?
+  @available(StdlibDeploymentTarget 6.2, *)
+  func run(_ job: consuming ExecutorJob,
+           at instant: Instant, tolerance: Duration?)
 
-  /// Convert a Swift Duration to a Clock-specific Duration
+  /// Enqueue the given job on the specified executor at some point after the
+  /// given instant.
   ///
-  /// Parameters:
-  ///
-  /// - from duration: The `Swift.Duration` to convert.
-  ///
-  /// Returns: A `Duration` representing the equivalent duration, or
-  ///          `nil` if this function is not supported.
-  @available(SwiftStdlib 6.2, *)
-  func convert(from duration: Swift.Duration) -> Duration?
-
-  /// Convert an `Instant` from some other clock's `Instant`
+  /// The default implementation uses the `run` method to trigger a job that
+  /// does `executor.enqueue(job)`.  If a particular `Clock` knows that the
+  /// executor it has been asked to use is the same one that it will run jobs
+  /// on, it can short-circuit this behaviour and directly use `run` with
+  /// the original job.
   ///
   /// Parameters:
   ///
-  /// - instant:    The instant to convert.
-  //  - from clock: The clock to convert from.
+  /// - job:         The job we wish to run
+  /// - on executor: The executor on which we would like it to run.
+  /// - at instant:  The time at which we would like it to run.
+  /// - tolerance:   The ideal maximum delay we are willing to tolerate.
   ///
-  /// Returns: An `Instant` representing the equivalent instant, or
-  ///          `nil` if this function is not supported.
-  @available(SwiftStdlib 6.2, *)
-  func convert<OtherClock: Clock>(instant: OtherClock.Instant,
-                                  from clock: OtherClock) -> Instant?
+  @available(StdlibDeploymentTarget 6.2, *)
+  func enqueue(_ job: consuming ExecutorJob,
+               on executor: some Executor,
+               at instant: Instant, tolerance: Duration?)
+#endif
 }
 
-@available(SwiftStdlib 5.7, *)
+#if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+extension Clock {
+  // The default implementation works by creating a trampoline and calling
+  // the run() method.
+  @available(StdlibDeploymentTarget 6.2, *)
+  public func enqueue(_ job: consuming ExecutorJob,
+                      on executor: some Executor,
+                      at instant: Instant, tolerance: Duration?) {
+    let trampoline = job.createTrampoline(to: executor)
+    run(trampoline, at: instant, tolerance: tolerance)
+  }
+
+  // Clocks that do not implement run will fatalError() if you try to use
+  // them with an executor that does not understand them.
+  @available(StdlibDeploymentTarget 6.2, *)
+  public func run(_ job: consuming ExecutorJob,
+                  at instant: Instant, tolerance: Duration?) {
+    fatalError("\(Self.self) does not implement run(_:at:tolerance:).")
+  }
+}
+#endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+
+@available(StdlibDeploymentTarget 5.7, *)
 extension Clock {
   /// Measure the elapsed time to execute a closure.
   ///
@@ -95,7 +107,7 @@ extension Clock {
   ///       let elapsed = clock.measure {
   ///          someWork()
   ///       }
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public func measure(_ work: () throws -> Void) rethrows -> Instant.Duration {
     let start = now
     try work()
@@ -109,7 +121,7 @@ extension Clock {
   ///       let elapsed = await clock.measure {
   ///          await someWork()
   ///       }
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   @_alwaysEmitIntoClient
   public func measure(
     isolation: isolated (any Actor)? = #isolation,
@@ -127,7 +139,7 @@ extension Clock {
   //
   // This function also doubles as an ABI-compatibility shim predating the
   // introduction of #isolation.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   @_silgen_name("$ss5ClockPsE7measurey8DurationQzyyYaKXEYaKF")
   @_unsafeInheritExecutor // for ABI compatibility
   public func _unsafeInheritExecutor_measure(
@@ -140,52 +152,14 @@ extension Clock {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
-extension Clock {
-  // For compatibility, return `nil` if this is not implemented
-  public func convert(from duration: Duration) -> Swift.Duration? {
-    return nil
-  }
-
-  public func convert(from duration: Swift.Duration) -> Duration? {
-    return nil
-  }
-
-  public func convert<OtherClock: Clock>(instant: OtherClock.Instant,
-                                  from clock: OtherClock) -> Instant? {
-    let ourNow = now
-    let otherNow = clock.now
-    let otherDuration = otherNow.duration(to: instant)
-
-    // Convert to `Swift.Duration`
-    guard let duration = clock.convert(from: otherDuration) else {
-      return nil
-    }
-
-    // Convert from `Swift.Duration`
-    guard let ourDuration = convert(from: duration) else {
-      return nil
-    }
-
-    return ourNow.advanced(by: ourDuration)
-  }
-}
-
-@available(SwiftStdlib 6.2, *)
-extension Clock where Duration == Swift.Duration {
-  public func convert(from duration: Duration) -> Duration? {
-    return duration
-  }
-}
-
 #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Clock {
   /// Suspends for the given duration.
   ///
   /// Prefer to use the `sleep(until:tolerance:)` method on `Clock` if you have
   /// access to an absolute instant.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   @_alwaysEmitIntoClient
   public func sleep(
     for duration: Instant.Duration,
@@ -196,64 +170,27 @@ extension Clock {
 }
 #endif
 
-/// Represents traits of a particular Clock implementation.
-///
-/// Clocks may be of a number of different varieties; executors will likely
-/// have specific clocks that they can use to schedule jobs, and will
-/// therefore need to be able to convert timestamps to an appropriate clock
-/// when asked to enqueue a job with a delay or deadline.
-///
-/// Choosing a clock in general requires the ability to tell which of their
-/// clocks best matches the clock that the user is trying to specify a
-/// time or delay in.  Executors are expected to do this on a best effort
-/// basis.
-@available(SwiftStdlib 6.2, *)
-public struct ClockTraits: OptionSet {
-  public let rawValue: UInt32
-
-  public init(rawValue: UInt32) {
-    self.rawValue = rawValue
-  }
-
-  /// Clocks with this trait continue running while the machine is asleep.
-  public static let continuous = ClockTraits(rawValue: 1 << 0)
-
-  /// Indicates that a clock's time will only ever increase.
-  public static let monotonic = ClockTraits(rawValue: 1 << 1)
-
-  /// Clocks with this trait are tied to "wall time".
-  public static let wallTime = ClockTraits(rawValue: 1 << 2)
-}
-
-@available(SwiftStdlib 6.2, *)
-extension Clock {
-  /// The traits associated with this clock instance.
-  @available(SwiftStdlib 6.2, *)
-  public var traits: ClockTraits {
-    return []
-  }
-}
-
 enum _ClockID: Int32 {
   case continuous = 1
   case suspending = 2
+  case walltime = 3
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_silgen_name("swift_get_time")
 internal func _getTime(
   seconds: UnsafeMutablePointer<Int64>,
   nanoseconds: UnsafeMutablePointer<Int64>,
   clock: CInt)
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_silgen_name("swift_get_clock_res")
 internal func _getClockRes(
   seconds: UnsafeMutablePointer<Int64>,
   nanoseconds: UnsafeMutablePointer<Int64>,
   clock: CInt)
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_sleep")
 internal func _sleep(
   seconds: Int64,
diff --git a/stdlib/public/Concurrency/ConcurrencyHooks.cpp b/stdlib/public/Concurrency/ConcurrencyHooks.cpp
index 26fd5c8159954..642f887e133c0 100644
--- a/stdlib/public/Concurrency/ConcurrencyHooks.cpp
+++ b/stdlib/public/Concurrency/ConcurrencyHooks.cpp
@@ -111,18 +111,20 @@ swift::swift_task_checkIsolated(SerialExecutorRef executor) {
     swift_task_checkIsolatedOrig(executor);
 }
 
-SWIFT_CC(swift) static bool
+SWIFT_CC(swift) static int8_t
 swift_task_isIsolatingCurrentContextOrig(SerialExecutorRef executor) {
   return swift_task_isIsolatingCurrentContextImpl(
       *reinterpret_cast<SwiftExecutorRef *>(&executor));
 }
 
-bool
+int8_t
 swift::swift_task_isIsolatingCurrentContext(SerialExecutorRef executor) {
-  if (SWIFT_UNLIKELY(swift_task_isIsolatingCurrentContext_hook))
-    return swift_task_isIsolatingCurrentContext_hook(executor, swift_task_isIsolatingCurrentContextOrig);
-  else
+  if (SWIFT_UNLIKELY(swift_task_isIsolatingCurrentContext_hook)) {
+    return swift_task_isIsolatingCurrentContext_hook(
+        executor, swift_task_isIsolatingCurrentContextOrig);
+  } else {
     return swift_task_isIsolatingCurrentContextOrig(executor);
+  }
 }
 
 // Implemented in Swift because we need to obtain the user-defined flags on the executor ref.
diff --git a/stdlib/public/Concurrency/ContinuousClock.swift b/stdlib/public/Concurrency/ContinuousClock.swift
index 979a3580d17ea..80ba7bdc51d1b 100644
--- a/stdlib/public/Concurrency/ContinuousClock.swift
+++ b/stdlib/public/Concurrency/ContinuousClock.swift
@@ -20,7 +20,7 @@ import Swift
 /// only comparable locally during the execution of a program.
 ///
 /// This clock is suitable for high resolution measurements of execution.
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_unavailableInEmbedded
 public struct ContinuousClock: Sendable {
   /// A continuous point in time used for `ContinuousClock`.
@@ -36,12 +36,12 @@ public struct ContinuousClock: Sendable {
 }
 
 #if !$Embedded
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension ContinuousClock.Instant: Codable {
 }
 #endif
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Duration {
   internal init(_seconds s: Int64, nanoseconds n: Int64) {
     let (secHi, secLo) = s.multipliedFullWidth(by: 1_000_000_000_000_000_000)
@@ -56,7 +56,7 @@ extension Duration {
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_unavailableInEmbedded
 extension Clock where Self == ContinuousClock {
   /// A clock that measures time that always increments but does not stop
@@ -64,11 +64,11 @@ extension Clock where Self == ContinuousClock {
   ///
   ///       try await Task.sleep(until: .now + .seconds(3), clock: .continuous)
   ///
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static var continuous: ContinuousClock { return ContinuousClock() }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_unavailableInEmbedded
 extension ContinuousClock: Clock {
   /// The current continuous instant.
@@ -100,12 +100,6 @@ extension ContinuousClock: Clock {
     )
   }
 
-  /// The continuous clock is continuous and monotonic
-  @available(SwiftStdlib 6.2, *)
-  public var traits: ClockTraits {
-    return [.continuous, .monotonic]
-  }
-
 #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
   /// Suspend task execution until a given deadline within a tolerance.
   /// If no tolerance is specified then the system may adjust the deadline
@@ -119,17 +113,16 @@ extension ContinuousClock: Clock {
   public func sleep(
     until deadline: Instant, tolerance: Swift.Duration? = nil
   ) async throws {
-    if #available(SwiftStdlib 6.2, *) {
+    if #available(StdlibDeploymentTarget 6.2, *) {
       try await Task._sleep(until: deadline,
                             tolerance: tolerance,
                             clock: self)
     } else {
-      // Should never see this
-      Builtin.unreachable()
+      fatalError("we should never get here; if we have, availability is broken")
     }
   }
 #else
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
   public func sleep(
     until deadline: Instant, tolerance: Swift.Duration? = nil
@@ -139,6 +132,16 @@ extension ContinuousClock: Clock {
 #endif
 }
 
+@available(StdlibDeploymentTarget 5.7, *)
+@_unavailableInEmbedded
+extension ContinuousClock {
+  @available(SwiftStdlib 5.7, *)
+  @_alwaysEmitIntoClient
+  public var systemEpoch: Instant {
+    unsafe unsafeBitCast(Duration.seconds(0), to: Instant.self)
+  }
+}
+
 @available(SwiftStdlib 5.7, *)
 @_unavailableInEmbedded
 extension ContinuousClock.Instant: InstantProtocol {
@@ -208,3 +211,36 @@ extension ContinuousClock.Instant: InstantProtocol {
     rhs.duration(to: lhs)
   }
 }
+
+#if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+@available(StdlibDeploymentTarget 6.2, *)
+extension ContinuousClock {
+
+  public func run(_ job: consuming ExecutorJob,
+                  at instant: Instant,
+                  tolerance: Duration?) {
+    guard let executor = Task<Never,Never>.currentSchedulingExecutor else {
+      fatalError("no scheduling executor is available")
+    }
+
+    executor.enqueue(job, at: instant,
+                     tolerance: tolerance,
+                     clock: self)
+  }
+
+  public func enqueue(_ job: consuming ExecutorJob,
+                      on executor: some Executor,
+                      at instant: Instant,
+                      tolerance: Duration?) {
+    if let schedulingExecutor = executor.asSchedulingExecutor {
+      schedulingExecutor.enqueue(job, at: instant,
+                                 tolerance: tolerance,
+                                 clock: self)
+    } else {
+      let trampoline = job.createTrampoline(to: executor)
+      run(trampoline, at: instant, tolerance: tolerance)
+    }
+  }
+
+}
+#endif
diff --git a/stdlib/public/Concurrency/CooperativeExecutor.swift b/stdlib/public/Concurrency/CooperativeExecutor.swift
index 794f9fc542a2a..78036141c808e 100644
--- a/stdlib/public/Concurrency/CooperativeExecutor.swift
+++ b/stdlib/public/Concurrency/CooperativeExecutor.swift
@@ -17,7 +17,7 @@ import Swift
 // Store the Timestamp in the executor private data, if it will fit; otherwise,
 // use the allocator to allocate space for it and stash a pointer in the private
 // data area.
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension ExecutorJob {
   fileprivate var cooperativeExecutorTimestampIsIndirect: Bool {
     return MemoryLayout<(Int, Int)>.size
@@ -97,16 +97,77 @@ extension ExecutorJob {
   }
 }
 
+#if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+/// A wait queue is a specialised priority queue used to run a timer.
+@available(StdlibDeploymentTarget 6.2, *)
+struct WaitQueue {
+  var queue: PriorityQueue<UnownedJob>
+  var clock: _ClockID
+
+  init(clock: _ClockID) {
+    queue = PriorityQueue(compare: {
+                            ExecutorJob($0).cooperativeExecutorTimestamp
+                              < ExecutorJob($1).cooperativeExecutorTimestamp
+                          })
+    self.clock = clock
+  }
+
+  var currentTime: CooperativeExecutor.Timestamp {
+    var now: CooperativeExecutor.Timestamp = .zero
+    unsafe _getTime(seconds: &now.seconds,
+                    nanoseconds: &now.nanoseconds,
+                    clock: clock.rawValue)
+    return now
+  }
+
+  mutating func enqueue(_ job: consuming ExecutorJob,
+                        after delay: CooperativeExecutor.Duration) {
+    let deadline = currentTime + delay
+    job.setupCooperativeExecutorTimestamp()
+    job.cooperativeExecutorTimestamp = deadline
+    queue.push(UnownedJob(job))
+  }
+
+  mutating func forEachReadyJob(body: (consuming ExecutorJob) -> ()) {
+    let now = currentTime
+    while let job = queue.pop(
+            when: {
+              ExecutorJob($0).cooperativeExecutorTimestamp < now
+            }) {
+      var theJob = ExecutorJob(job)
+      theJob.clearCooperativeExecutorTimestamp()
+      body(theJob)
+    }
+  }
+
+  var timeToNextJob: CooperativeExecutor.Duration? {
+    if let job = queue.top {
+      let deadline = ExecutorJob(job).cooperativeExecutorTimestamp
+      let now = currentTime
+      if deadline > now {
+        return deadline - now
+      } else {
+        return CooperativeExecutor.Duration(seconds: 0, nanoseconds: 0)
+      }
+    }
+    return nil
+  }
+}
+#endif
+
 /// A co-operative executor that can be used as the main executor or as a
 /// task executor.
-@available(SwiftStdlib 6.2, *)
-class CooperativeExecutor: Executor, @unchecked Sendable {
+@available(StdlibDeploymentTarget 6.2, *)
+final class CooperativeExecutor: Executor, @unchecked Sendable {
   var runQueue: PriorityQueue<UnownedJob>
-  var waitQueue: PriorityQueue<UnownedJob>
+  #if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+  var suspendingWaitQueue = WaitQueue(clock: .suspending)
+  var continuousWaitQueue = WaitQueue(clock: .continuous)
+  #endif
   var shouldStop: Bool = false
 
   /// Internal representation of a duration for CooperativeExecutor
-  struct Duration {
+  struct Duration: Comparable {
     var seconds: Int64
     var nanoseconds: Int64
 
@@ -120,6 +181,16 @@ class CooperativeExecutor: Executor, @unchecked Sendable {
       self.seconds = seconds
       self.nanoseconds = attoseconds / 1_000_000_000
     }
+
+    static func == (lhs: Duration, rhs: Duration) -> Bool {
+      return lhs.seconds == rhs.seconds && lhs.nanoseconds == rhs.nanoseconds
+    }
+    static func < (lhs: Duration, rhs: Duration) -> Bool {
+      return lhs.seconds < rhs.seconds || (
+        lhs.seconds == rhs.seconds
+          && lhs.nanoseconds < rhs.nanoseconds
+      )
+    }
   }
 
   /// Internal representation of a timestamp for CooperativeExecutor
@@ -163,11 +234,6 @@ class CooperativeExecutor: Executor, @unchecked Sendable {
 
   public init() {
     runQueue = PriorityQueue(compare: { $0.priority > $1.priority })
-    waitQueue =
-      PriorityQueue(compare: {
-                      ExecutorJob($0).cooperativeExecutorTimestamp
-                        < ExecutorJob($1).cooperativeExecutorTimestamp
-                    })
   }
 
   public func enqueue(_ job: consuming ExecutorJob) {
@@ -175,17 +241,21 @@ class CooperativeExecutor: Executor, @unchecked Sendable {
   }
 
   public var isMainExecutor: Bool { true }
-
-  public var asSchedulable: any SchedulableExecutor { self }
 }
 
-@available(SwiftStdlib 6.2, *)
-extension CooperativeExecutor: SchedulableExecutor {
-  var currentTime: Timestamp {
+#if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+@available(StdlibDeploymentTarget 6.2, *)
+extension CooperativeExecutor: SchedulingExecutor {
+
+  public var asScheduling: (any SchedulingExecutor)? {
+    return self
+  }
+
+  func currentTime(clock: _ClockID) -> Timestamp {
     var now: Timestamp = .zero
     unsafe _getTime(seconds: &now.seconds,
                     nanoseconds: &now.nanoseconds,
-                    clock: _ClockID.suspending.rawValue)
+                    clock: clock.rawValue)
     return now
   }
 
@@ -193,16 +263,26 @@ extension CooperativeExecutor: SchedulableExecutor {
                                 after delay: C.Duration,
                                 tolerance: C.Duration? = nil,
                                 clock: C) {
-    let duration = Duration(from: clock.convert(from: delay)!)
-    let deadline = self.currentTime + duration
-
-    job.setupCooperativeExecutorTimestamp()
-    job.cooperativeExecutorTimestamp = deadline
-    waitQueue.push(UnownedJob(job))
+    // If it's a clock we know, get the duration to wait
+    if let _ = clock as? ContinuousClock {
+      let continuousDuration = delay as! ContinuousClock.Duration
+      let duration = Duration(from: continuousDuration)
+      continuousWaitQueue.enqueue(job, after: duration)
+    } else if let _ = clock as? SuspendingClock {
+      let suspendingDuration = delay as! SuspendingClock.Duration
+      let duration = Duration(from: suspendingDuration)
+      suspendingWaitQueue.enqueue(job, after: duration)
+    } else {
+      clock.enqueue(job, on: self, at: clock.now.advanced(by: delay),
+                    tolerance: tolerance)
+      return
+    }
   }
+
 }
+#endif
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension CooperativeExecutor: RunLoopExecutor {
   public func run() throws {
     try runUntil { false }
@@ -211,36 +291,47 @@ extension CooperativeExecutor: RunLoopExecutor {
   public func runUntil(_ condition: () -> Bool) throws {
     shouldStop = false
     while !shouldStop && !condition() {
-      // Process the timer queue
-      let now = currentTime
-      while let job = waitQueue.pop(when: {
-                                      ExecutorJob($0).cooperativeExecutorTimestamp <= now
-                                    }) {
-        var theJob = ExecutorJob(job)
-        theJob.clearCooperativeExecutorTimestamp()
-        runQueue.push(job)
+      #if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+      // Process the timer queues
+      suspendingWaitQueue.forEachReadyJob {
+        runQueue.push(UnownedJob($0))
+      }
+      continuousWaitQueue.forEachReadyJob {
+        runQueue.push(UnownedJob($0))
       }
+      #endif
 
       // Now run any queued jobs
-      while let job = runQueue.pop() {
+      var runQ = runQueue.take()
+      while let job = runQ.pop() {
         unsafe ExecutorJob(job).runSynchronously(
           on: self.asUnownedSerialExecutor()
         )
       }
 
+      #if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
       // Finally, wait until the next deadline
-      if let job = waitQueue.top {
-        let deadline = ExecutorJob(job).cooperativeExecutorTimestamp
-        let now = self.currentTime
-        if deadline > now {
-          let toWait = deadline - now
-          _sleep(seconds: toWait.seconds,
-                 nanoseconds: toWait.nanoseconds)
+      var toWait: Duration? = suspendingWaitQueue.timeToNextJob
+
+      if let continuousToWait = continuousWaitQueue.timeToNextJob {
+        if toWait == nil ||  continuousToWait < toWait! {
+          toWait = continuousToWait
         }
-      } else {
+      }
+
+      if let toWait {
+        _sleep(seconds: toWait.seconds,
+               nanoseconds: toWait.nanoseconds)
+      } else if runQueue.isEmpty {
+        // Stop if no more jobs are available
+        break
+      }
+      #else // $Embedded || SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+      if runQueue.isEmpty {
         // Stop if no more jobs are available
         break
       }
+      #endif
     }
   }
 
@@ -249,13 +340,13 @@ extension CooperativeExecutor: RunLoopExecutor {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension CooperativeExecutor: SerialExecutor {}
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension CooperativeExecutor: TaskExecutor {}
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension CooperativeExecutor: MainExecutor {}
 
 #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
diff --git a/stdlib/public/Concurrency/CooperativeGlobalExecutor.cpp b/stdlib/public/Concurrency/CooperativeGlobalExecutor.cpp
index 7cc503e836c25..647b90421d798 100644
--- a/stdlib/public/Concurrency/CooperativeGlobalExecutor.cpp
+++ b/stdlib/public/Concurrency/CooperativeGlobalExecutor.cpp
@@ -155,7 +155,7 @@ void swift_task_checkIsolatedImpl(SwiftExecutorRef executor) {
 }
 
 SWIFT_CC(swift)
-bool swift_task_isIsolatingCurrentContextImpl(SwiftExecutorRef executor) {
+int8_t swift_task_isIsolatingCurrentContextImpl(SwiftExecutorRef executor) {
   return swift_executor_invokeSwiftIsIsolatingCurrentContext(executor);
 }
 
diff --git a/stdlib/public/Concurrency/Debug.h b/stdlib/public/Concurrency/Debug.h
index 858f0b903caa2..17df69957beb1 100644
--- a/stdlib/public/Concurrency/Debug.h
+++ b/stdlib/public/Concurrency/Debug.h
@@ -34,6 +34,10 @@ const void *const _swift_concurrency_debug_jobMetadata;
 SWIFT_EXPORT_FROM(swift_Concurrency)
 const void *const _swift_concurrency_debug_asyncTaskMetadata;
 
+/// The size of an AsyncTask, in bytes.
+SWIFT_EXPORT_FROM(swift_Concurrency)
+const size_t _swift_concurrency_debug_asyncTaskSize;
+
 /// A fake metadata pointer placed at the start of async task slab allocations.
 SWIFT_EXPORT_FROM(swift_Concurrency)
 const void *const _swift_concurrency_debug_asyncTaskSlabMetadata;
diff --git a/stdlib/public/Concurrency/Deque/Deque+UnsafeHandle.swift b/stdlib/public/Concurrency/Deque/Deque+UnsafeHandle.swift
index 683b5a2b264fc..8fe4b07e467f6 100644
--- a/stdlib/public/Concurrency/Deque/Deque+UnsafeHandle.swift
+++ b/stdlib/public/Concurrency/Deque/Deque+UnsafeHandle.swift
@@ -63,7 +63,7 @@ extension _Deque._UnsafeHandle {
 
   var startSlot: Slot {
     get { unsafe _header.pointee.startSlot }
-    nonmutating set { unsafe _header.pointee.startSlot = unsafe newValue }
+    nonmutating set { unsafe _header.pointee.startSlot = newValue }
   }
 
   func ptr(at slot: Slot) -> UnsafeMutablePointer<Element> {
@@ -99,28 +99,28 @@ extension _Deque._UnsafeHandle {
 
   internal func slot(after slot: Slot) -> Slot {
     unsafe assert(slot.position < capacity)
-    let position = unsafe slot.position + 1
+    let position = slot.position + 1
     if unsafe position >= capacity {
-      return unsafe Slot(at: 0)
+      return Slot(at: 0)
     }
-    return unsafe Slot(at: position)
+    return Slot(at: position)
   }
 
   internal func slot(before slot: Slot) -> Slot {
     unsafe assert(slot.position < capacity)
-    if unsafe slot.position == 0 { return unsafe Slot(at: capacity - 1) }
-    return unsafe Slot(at: slot.position - 1)
+    if slot.position == 0 { return unsafe Slot(at: capacity - 1) }
+    return Slot(at: slot.position - 1)
   }
 
   internal func slot(_ slot: Slot, offsetBy delta: Int) -> Slot {
     unsafe assert(slot.position <= capacity)
-    let position = unsafe slot.position + delta
+    let position = slot.position + delta
     if delta >= 0 {
       if unsafe position >= capacity { return unsafe Slot(at: position - capacity) }
     } else {
       if position < 0 { return unsafe Slot(at: position + capacity) }
     }
-    return unsafe Slot(at: position)
+    return Slot(at: position)
   }
 
   internal var endSlot: Slot {
@@ -139,7 +139,7 @@ extension _Deque._UnsafeHandle {
     // random-access subscript operations. (Up to 2x on some microbenchmarks.)
     let position = unsafe startSlot.position &+ offset
     guard unsafe position < capacity else { return unsafe Slot(at: position &- capacity) }
-    return unsafe Slot(at: position)
+    return Slot(at: position)
   }
 }
 
@@ -199,9 +199,9 @@ extension _Deque._UnsafeHandle {
     from source: UnsafeBufferPointer<Element>
   ) -> Slot {
     unsafe assert(start.position + source.count <= capacity)
-    guard source.count > 0 else { return unsafe start }
+    guard source.count > 0 else { return start }
     unsafe ptr(at: start).initialize(from: source.baseAddress!, count: source.count)
-    return unsafe Slot(at: start.position + source.count)
+    return Slot(at: start.position + source.count)
   }
 
   @discardableResult
@@ -210,9 +210,9 @@ extension _Deque._UnsafeHandle {
     from source: UnsafeMutableBufferPointer<Element>
   ) -> Slot {
     unsafe assert(start.position + source.count <= capacity)
-    guard source.count > 0 else { return unsafe start }
+    guard source.count > 0 else { return start }
     unsafe ptr(at: start).moveInitialize(from: source.baseAddress!, count: source.count)
-    return unsafe Slot(at: start.position + source.count)
+    return Slot(at: start.position + source.count)
   }
 
   @discardableResult
@@ -224,7 +224,7 @@ extension _Deque._UnsafeHandle {
     assert(count >= 0)
     unsafe assert(source.position + count <= self.capacity)
     unsafe assert(target.position + count <= self.capacity)
-    guard count > 0 else { return unsafe (source, target) }
+    guard count > 0 else { return (source, target) }
     unsafe ptr(at: target).moveInitialize(from: ptr(at: source), count: count)
     return unsafe (slot(source, offsetBy: count), slot(target, offsetBy: count))
   }
@@ -451,7 +451,7 @@ extension _Deque._UnsafeHandle {
   ) -> _UnsafeMutableWrappedBuffer<Element> {
     unsafe assert(start.position <= capacity)
     unsafe assert(end.position <= capacity)
-    if unsafe start < end {
+    if start < end {
       return unsafe .init(start: ptr(at: start), count: end.position - start.position)
     }
     return unsafe .init(
diff --git a/stdlib/public/Concurrency/DiscardingTaskGroup.swift b/stdlib/public/Concurrency/DiscardingTaskGroup.swift
index 1de2e5311abcf..bfb8246da2d86 100644
--- a/stdlib/public/Concurrency/DiscardingTaskGroup.swift
+++ b/stdlib/public/Concurrency/DiscardingTaskGroup.swift
@@ -22,10 +22,10 @@ import Swift
 /// best applied in situations where the result of a child task is some form
 /// of side-effect.
 ///
-/// A group waits for all of its child tasks
-/// to complete before it returns. Even cancelled tasks must run until
+/// A group *always* waits for all of its child tasks
+/// to complete before it returns. Even canceled tasks must run until
 /// completion before this function returns.
-/// Cancelled child tasks cooperatively react to cancellation and attempt
+/// Canceled child tasks cooperatively react to cancellation and attempt
 /// to return as early as possible.
 /// After this function returns, the task group is always empty.
 ///
@@ -41,6 +41,8 @@ import Swift
 /// // guaranteed that slow-task has completed and the group is empty & destroyed
 /// ```
 ///
+/// Refer to ``TaskGroup`` documentation for detailed discussion of semantics shared between all task groups.
+///
 /// Task Group Cancellation
 /// =======================
 ///
@@ -65,6 +67,7 @@ import Swift
 /// For tasks that need to handle cancellation by throwing an error,
 /// use the `withThrowingDiscardingTaskGroup(returning:body:)` method instead.
 ///
+/// - SeeAlso: ``TaskGroup``
 /// - SeeAlso: ``withThrowingDiscardingTaskGroup(returning:body:)``
 @available(SwiftStdlib 5.9, *)
 #if !hasFeature(Embedded)
@@ -80,7 +83,7 @@ public func withDiscardingTaskGroup<GroupResult>(
     discardResults: true
   )
 
-  let _group = Builtin.createTaskGroupWithFlags(flags, GroupResult.self)
+  let _group = Builtin.createTaskGroupWithFlags(flags, Void.self)
   var group = DiscardingTaskGroup(group: _group)
   defer { Builtin.destroyTaskGroup(_group) }
 
@@ -108,7 +111,7 @@ public func _unsafeInheritExecutor_withDiscardingTaskGroup<GroupResult>(
     discardResults: true
   )
 
-  let _group = Builtin.createTaskGroupWithFlags(flags, GroupResult.self)
+  let _group = Builtin.createTaskGroupWithFlags(flags, Void.self)
   var group = DiscardingTaskGroup(group: _group)
   defer { Builtin.destroyTaskGroup(_group) }
 
@@ -131,9 +134,7 @@ public func _unsafeInheritExecutor_withDiscardingTaskGroup<GroupResult>(
 /// and mutation operations can't be performed
 /// from a concurrent execution context like a child task.
 ///
-/// ### Task execution order
-/// Tasks added to a task group execute concurrently, and may be scheduled in
-/// any order.
+/// Refer to ``TaskGroup`` documentation for detailed discussion of semantics shared between all task groups.
 ///
 /// ### Discarding behavior
 /// A discarding task group eagerly discards and releases its child tasks as
@@ -142,18 +143,18 @@ public func _unsafeInheritExecutor_withDiscardingTaskGroup<GroupResult>(
 /// be the case with a ``TaskGroup``.
 ///
 /// ### Cancellation behavior
-/// A discarding task group becomes cancelled in one of the following ways:
+/// A discarding task group becomes canceled in one of the following ways:
 ///
 /// - when ``cancelAll()`` is invoked on it,
-/// - when the ``Task`` running this task group is cancelled.
+/// - when the ``Task`` running this task group is canceled.
 ///
 /// Since a `DiscardingTaskGroup` is a structured concurrency primitive, cancellation is
 /// automatically propagated through all of its child-tasks (and their child
 /// tasks).
 ///
-/// A cancelled task group can still keep adding tasks, however they will start
-/// being immediately cancelled, and may act accordingly to this. To avoid adding
-/// new tasks to an already cancelled task group, use ``addTaskUnlessCancelled(priority:body:)``
+/// A canceled task group can still keep adding tasks, however they will start
+/// being immediately canceled, and may act accordingly to this. To avoid adding
+/// new tasks to an already canceled task group, use ``addTaskUnlessCancelled(priority:body:)``
 /// rather than the plain ``addTask(priority:body:)`` which adds tasks unconditionally.
 ///
 /// For information about the language-level concurrency model that `DiscardingTaskGroup` is part of,
@@ -204,7 +205,7 @@ public struct DiscardingTaskGroup {
   /// If you add a task to a group after canceling the group,
   /// that task is canceled immediately after being added to the group.
   ///
-  /// Immediately cancelled child tasks should therefore cooperatively check for and
+  /// Immediately canceled child tasks should therefore cooperatively check for and
   /// react  to cancellation, e.g. by throwing an `CancellationError` at their
   /// earliest convenience, or otherwise handling the cancellation.
   ///
@@ -245,10 +246,10 @@ extension DiscardingTaskGroup: Sendable { }
 /// best applied in situations where the result of a child task is some form
 /// of side-effect.
 ///
-/// A group waits for all of its child tasks
-/// to complete before it returns. Even cancelled tasks must run until
+/// A group *always* waits for all of its child tasks
+/// to complete before it returns. Even canceled tasks must run until
 /// completion before this function returns.
-/// Cancelled child tasks cooperatively react to cancellation and attempt
+/// Canceled child tasks cooperatively react to cancellation and attempt
 /// to return as early as possible.
 /// After this function returns, the task group is always empty.
 ///
@@ -264,6 +265,8 @@ extension DiscardingTaskGroup: Sendable { }
 /// // guaranteed that slow-task has completed and the group is empty & destroyed
 /// ```
 ///
+/// Refer to ``TaskGroup`` documentation for detailed discussion of semantics shared between all task groups.
+///
 /// Task Group Cancellation
 /// =======================
 ///
@@ -347,7 +350,7 @@ public func withThrowingDiscardingTaskGroup<GroupResult>(
       discardResults: true
   )
 
-  let _group = Builtin.createTaskGroupWithFlags(flags, GroupResult.self)
+  let _group = Builtin.createTaskGroupWithFlags(flags, Void.self)
   var group = ThrowingDiscardingTaskGroup<Error>(group: _group)
   defer { Builtin.destroyTaskGroup(_group) }
 
@@ -378,7 +381,7 @@ public func _unsafeInheritExecutor_withThrowingDiscardingTaskGroup<GroupResult>(
       discardResults: true
   )
 
-  let _group = Builtin.createTaskGroupWithFlags(flags, GroupResult.self)
+  let _group = Builtin.createTaskGroupWithFlags(flags, Void.self)
   var group = ThrowingDiscardingTaskGroup<Error>(group: _group)
   defer { Builtin.destroyTaskGroup(_group) }
 
@@ -411,9 +414,7 @@ public func _unsafeInheritExecutor_withThrowingDiscardingTaskGroup<GroupResult>(
 /// and mutation operations can't be performed
 /// from a concurrent execution context like a child task.
 ///
-/// ### Task execution order
-/// Tasks added to a task group execute concurrently, and may be scheduled in
-/// any order.
+/// Refer to ``TaskGroup`` documentation for detailed discussion of semantics shared between all task groups.
 ///
 /// ### Discarding behavior
 /// A discarding task group eagerly discards and releases its child tasks as
@@ -422,20 +423,20 @@ public func _unsafeInheritExecutor_withThrowingDiscardingTaskGroup<GroupResult>(
 /// be the case with a ``TaskGroup``.
 ///
 /// ### Cancellation behavior
-/// A throwing discarding task group becomes cancelled in one of the following ways:
+/// A throwing discarding task group becomes canceled in one of the following ways:
 ///
 /// - when ``cancelAll()`` is invoked on it,
 /// - when an error is thrown out of the `withThrowingDiscardingTaskGroup { ... }` closure,
-/// - when the ``Task`` running this task group is cancelled.
+/// - when the ``Task`` running this task group is canceled.
 ///
 /// But also, and uniquely in *discarding* task groups:
 /// - when *any* of its child tasks throws.
 ///
-/// The group becoming cancelled automatically, and cancelling all of its child tasks,
+/// The group becoming canceled automatically, and cancelling all of its child tasks,
 /// whenever *any* child task throws an error is a behavior unique to discarding task groups,
 /// because achieving such semantics is not possible otherwise, due to the missing `next()` method
 /// on discarding groups. Accumulating task groups can implement this by manually polling `next()`
-/// and deciding to `cancelAll()` when they decide an error should cause the group to become cancelled,
+/// and deciding to `cancelAll()` when they decide an error should cause the group to become canceled,
 /// however a discarding group cannot poll child tasks for results and therefore assumes that child
 /// task throws are an indication of a group wide failure. In order to avoid such behavior,
 /// use a ``DiscardingTaskGroup`` instead of a throwing one, or catch specific errors in
@@ -445,9 +446,9 @@ public func _unsafeInheritExecutor_withThrowingDiscardingTaskGroup<GroupResult>(
 /// automatically propagated through all of its child-tasks (and their child
 /// tasks).
 ///
-/// A cancelled task group can still keep adding tasks, however they will start
-/// being immediately cancelled, and may act accordingly to this. To avoid adding
-/// new tasks to an already cancelled task group, use ``addTaskUnlessCancelled(priority:body:)``
+/// A canceled task group can still keep adding tasks, however they will start
+/// being immediately canceled, and may act accordingly to this. To avoid adding
+/// new tasks to an already canceled task group, use ``addTaskUnlessCancelled(priority:body:)``
 /// rather than the plain ``addTask(priority:body:)`` which adds tasks unconditionally.
 ///
 /// For information about the language-level concurrency model that `DiscardingTaskGroup` is part of,
@@ -496,7 +497,7 @@ public struct ThrowingDiscardingTaskGroup<Failure: Error> {
   /// If you add a task to a group after canceling the group,
   /// that task is canceled immediately after being added to the group.
   ///
-  /// Immediately cancelled child tasks should therefore cooperatively check for and
+  /// Immediately canceled child tasks should therefore cooperatively check for and
   /// react  to cancellation, e.g. by throwing an `CancellationError` at their
   /// earliest convenience, or otherwise handling the cancellation.
   ///
diff --git a/stdlib/public/Concurrency/DispatchExecutor.swift b/stdlib/public/Concurrency/DispatchExecutor.swift
index ccc29c75f5ca6..0910848ccd96b 100644
--- a/stdlib/public/Concurrency/DispatchExecutor.swift
+++ b/stdlib/public/Concurrency/DispatchExecutor.swift
@@ -23,8 +23,10 @@ import Swift
 
 // .. Main Executor ............................................................
 
-@available(SwiftStdlib 6.2, *)
-public class DispatchMainExecutor: RunLoopExecutor, @unchecked Sendable {
+/// A Dispatch-based main executor.
+@available(StdlibDeploymentTarget 6.2, *)
+class DispatchMainExecutor: RunLoopExecutor, SchedulingExecutor,
+                            @unchecked Sendable {
   var threaded = false
 
   public init() {}
@@ -41,9 +43,21 @@ public class DispatchMainExecutor: RunLoopExecutor, @unchecked Sendable {
   public func stop() {
     fatalError("DispatchMainExecutor cannot be stopped")
   }
+
+  var asScheduling: (any SchedulingExecutor)? {
+    return self
+  }
+
+  public func enqueue<C: Clock>(_ job: consuming ExecutorJob,
+                                at instant: C.Instant,
+                                tolerance: C.Duration? = nil,
+                                clock: C) {
+    _dispatchEnqueue(job, at: instant, tolerance: tolerance, clock: clock,
+                     executor: self, global: false)
+  }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension DispatchMainExecutor: SerialExecutor {
 
   public func enqueue(_ job: consuming ExecutorJob) {
@@ -57,42 +71,15 @@ extension DispatchMainExecutor: SerialExecutor {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
-extension DispatchMainExecutor: SchedulableExecutor {
-  public var asSchedulable: SchedulableExecutor? {
-    return self
-  }
-
-  public func enqueue<C: Clock>(_ job: consuming ExecutorJob,
-                                at instant: C.Instant,
-                                tolerance: C.Duration? = nil,
-                                clock: C) {
-    let tolSec, tolNanosec: CLongLong
-    if let tolerance = tolerance {
-      (tolSec, tolNanosec) = delay(from: tolerance, clock: clock)
-    } else {
-      tolSec = 0
-      tolNanosec = -1
-    }
-
-    let (clockID, seconds, nanoseconds) = timestamp(for: instant, clock: clock)
-
-    _dispatchEnqueueWithDeadline(CBool(false),
-                                 CLongLong(seconds), CLongLong(nanoseconds),
-                                 CLongLong(tolSec), CLongLong(tolNanosec),
-                                 clockID.rawValue,
-                                 UnownedJob(job))
-  }
-}
-
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension DispatchMainExecutor: MainExecutor {}
 
 // .. Task Executor ............................................................
 
-@available(SwiftStdlib 6.2, *)
-public class DispatchGlobalTaskExecutor: TaskExecutor, SchedulableExecutor,
-                                         @unchecked Sendable {
+/// A Dispatch-based `TaskExecutor`
+@available(StdlibDeploymentTarget 6.2, *)
+class DispatchGlobalTaskExecutor: TaskExecutor, SchedulingExecutor,
+                                  @unchecked Sendable {
   public init() {}
 
   public func enqueue(_ job: consuming ExecutorJob) {
@@ -101,103 +88,98 @@ public class DispatchGlobalTaskExecutor: TaskExecutor, SchedulableExecutor,
 
   public var isMainExecutor: Bool { false }
 
+  var asScheduling: (any SchedulingExecutor)? {
+    return self
+  }
+
   public func enqueue<C: Clock>(_ job: consuming ExecutorJob,
                                 at instant: C.Instant,
                                 tolerance: C.Duration? = nil,
                                 clock: C) {
-    let tolSec, tolNanosec: CLongLong
-    if let tolerance = tolerance {
-      (tolSec, tolNanosec) = delay(from: tolerance, clock: clock)
-    } else {
-      tolSec = 0
-      tolNanosec = -1
-    }
-
-    let (clockID, seconds, nanoseconds) = timestamp(for: instant, clock: clock)
-
-    _dispatchEnqueueWithDeadline(CBool(true),
-                                 CLongLong(seconds), CLongLong(nanoseconds),
-                                 CLongLong(tolSec), CLongLong(tolNanosec),
-                                 clockID.rawValue,
-                                 UnownedJob(job))
+    _dispatchEnqueue(job, at: instant, tolerance: tolerance, clock: clock,
+                     executor: self, global: true)
   }
 }
 
 // .. Clock Support ............................................................
 
-/// DispatchMainExecutor and DispatchTaskExecutor both implement this
-/// protocol.
-///
-/// It is used to help convert instants and durations from arbitrary `Clock`s
-/// to Dispatch's time base.
-@available(SwiftStdlib 6.2, *)
-protocol DispatchExecutorProtocol: Executor {
-
-  /// Convert an `Instant` from the specified clock to a tuple identifying
-  /// the Dispatch clock and the seconds and nanoseconds components.
-  ///
-  /// Parameters:
-  ///
-  /// - for instant: The `Instant` to convert.
-  /// - clock:       The `Clock` instant that the `Instant` came from.
-  ///
-  /// Returns: A tuple of `(clockID, seconds, nanoseconds)`.
-  func timestamp<C: Clock>(for instant: C.Instant, clock: C)
-    -> (clockID: DispatchClockID, seconds: Int64, nanoseconds: Int64)
-
-  /// Convert a `Duration` from the specified clock to a tuple containing
-  /// seconds and nanosecond components.
-  func delay<C: Clock>(from duration: C.Duration, clock: C)
-    -> (seconds: Int64, nanoseconds: Int64)
-
-}
-
 /// An enumeration identifying one of the Dispatch-supported clocks
 enum DispatchClockID: CInt {
   case continuous = 1
   case suspending = 2
+  case walltime = 3
 }
 
-@available(SwiftStdlib 6.2, *)
-extension DispatchExecutorProtocol {
-
-  func timestamp<C: Clock>(for instant: C.Instant, clock: C)
-    -> (clockID: DispatchClockID, seconds: Int64, nanoseconds: Int64) {
-    if clock.traits.contains(.continuous) {
-        let dispatchClock: ContinuousClock = .continuous
-        let instant = dispatchClock.convert(instant: instant, from: clock)!
-        let (seconds, attoseconds) = instant._value.components
-        let nanoseconds = attoseconds / 1_000_000_000
-        return (clockID: .continuous,
-                seconds: Int64(seconds),
-                nanoseconds: Int64(nanoseconds))
-    } else {
-        let dispatchClock: SuspendingClock = .suspending
-        let instant = dispatchClock.convert(instant: instant, from: clock)!
-        let (seconds, attoseconds) = instant._value.components
-        let nanoseconds = attoseconds / 1_000_000_000
-        return (clockID: .suspending,
-                seconds: Int64(seconds),
-                nanoseconds: Int64(nanoseconds))
-    }
+fileprivate func clamp(_ components: (seconds: Int64, attoseconds: Int64))
+  -> (seconds: Int64, attoseconds: Int64) {
+  if components.seconds < 0
+       || components.seconds == 0 && components.attoseconds < 0 {
+    return (seconds: 0, attoseconds: 0)
   }
+  return (seconds: components.seconds, attoseconds: components.attoseconds)
+}
 
-  func delay<C: Clock>(from duration: C.Duration, clock: C)
-    -> (seconds: Int64, nanoseconds: Int64) {
-    let swiftDuration = clock.convert(from: duration)!
-    let (seconds, attoseconds) = swiftDuration.components
-    let nanoseconds = attoseconds / 1_000_000_000
-    return (seconds: seconds, nanoseconds: nanoseconds)
-  }
+fileprivate func delay(from duration: Swift.Duration) -> (
+  seconds: Int64, nanoseconds: Int64
+) {
+  let (seconds, attoseconds) = clamp(duration.components)
+  let nanoseconds = attoseconds / 1_000_000_000
+  return (seconds: seconds, nanoseconds: nanoseconds)
+}
 
+fileprivate func timestamp<C: Clock>(for instant: C.Instant, clock: C)
+  -> (clockID: _ClockID, seconds: Int64, nanoseconds: Int64)? {
+  if let continuousClock = clock as? ContinuousClock {
+    return continuousClock.timestamp(for: instant as! ContinuousClock.Instant)
+  } else if let suspendingClock = clock as? SuspendingClock {
+    return suspendingClock.timestamp(for: instant as! SuspendingClock.Instant)
+  }
+  return nil
 }
 
-@available(SwiftStdlib 6.2, *)
-extension DispatchGlobalTaskExecutor: DispatchExecutorProtocol {
+fileprivate func durationComponents<C: Clock>(for duration: C.Duration, clock: C)
+  -> (seconds: Int64, nanoseconds: Int64) {
+  if let continuousClock = clock as? ContinuousClock {
+    return continuousClock.durationComponents(for: duration as! ContinuousClock.Duration)
+  } else if let suspendingClock = clock as? SuspendingClock {
+    return suspendingClock.durationComponents(for: duration as! SuspendingClock.Duration)
+  }
+  // This shouldn't be reachable
+  fatalError("unknown clock in Dispatch Executor")
 }
 
-@available(SwiftStdlib 6.2, *)
-extension DispatchMainExecutor: DispatchExecutorProtocol {
+@available(StdlibDeploymentTarget 6.2, *)
+fileprivate func _dispatchEnqueue<C: Clock, E: Executor>(
+  _ job: consuming ExecutorJob,
+  at instant: C.Instant,
+  tolerance: C.Duration?,
+  clock: C,
+  executor: E,
+  global: Bool
+) {
+  // If it's a clock we know, convert it to something we can use; otherwise,
+  // call the clock's `enqueue` function to schedule the enqueue of the job.
+
+  guard let (clockID, seconds, nanoseconds) = timestamp(for: instant,
+                                                        clock: clock) else {
+    clock.enqueue(job, on: executor, at: instant, tolerance: tolerance)
+    return
+  }
+
+  let tolSec: Int64, tolNanosec: Int64
+  if let tolerance = tolerance {
+    (tolSec, tolNanosec) = durationComponents(for: tolerance,
+                                              clock: clock)
+  } else {
+    tolSec = 0
+    tolNanosec = -1
+  }
+
+  _dispatchEnqueueWithDeadline(CBool(global),
+                               CLongLong(seconds), CLongLong(nanoseconds),
+                               CLongLong(tolSec), CLongLong(tolNanosec),
+                               clockID.rawValue,
+                               UnownedJob(job))
 }
 
 #endif // !$Embedded && !os(WASI)
diff --git a/stdlib/public/Concurrency/DispatchGlobalExecutor.cpp b/stdlib/public/Concurrency/DispatchGlobalExecutor.cpp
index b5face3c0fbb3..db649c9193138 100644
--- a/stdlib/public/Concurrency/DispatchGlobalExecutor.cpp
+++ b/stdlib/public/Concurrency/DispatchGlobalExecutor.cpp
@@ -30,9 +30,9 @@
 
 #include <cstddef>
 
+#include "swift/Basic/Casting.h"
 #include "swift/Runtime/Concurrency.h"
 #include "swift/Runtime/EnvironmentVariables.h"
-#include "swift/Runtime/STLCompatibility.h"
 
 #if SWIFT_CONCURRENCY_ENABLE_DISPATCH
 #include "swift/Runtime/HeapObject.h"
@@ -55,6 +55,10 @@
 #include "ExecutorImpl.h"
 #include "TaskPrivate.h"
 
+#ifndef NSEC_PER_SEC
+#define NSEC_PER_SEC 1000000000ull
+#endif
+
 using namespace swift;
 
 /// The function passed to dispatch_async_f to execute a job.
@@ -99,11 +103,17 @@ static void initializeDispatchEnqueueFunc(dispatch_queue_t queue, void *obj,
   if (SWIFT_RUNTIME_WEAK_CHECK(dispatch_async_swift_job))
     func = SWIFT_RUNTIME_WEAK_USE(dispatch_async_swift_job);
 #elif defined(_WIN32)
-  func = std::bit_cast<dispatchEnqueueFuncType>(
+#if SwiftConcurrency_HAS_DISPATCH_ASYNC_SWIFT_JOB
+#if defined(dispatch_STATIC)
+  func = dispatch_async_swift_job;
+#else
+  func = function_cast<dispatchEnqueueFuncType>(
       GetProcAddress(LoadLibraryW(L"dispatch.dll"),
       "dispatch_async_swift_job"));
+#endif
+#endif
 #else
-  func = std::bit_cast<dispatchEnqueueFuncType>(
+  func = function_cast<dispatchEnqueueFuncType>(
       dlsym(RTLD_NEXT, "dispatch_async_swift_job"));
 #endif
 #endif
@@ -294,7 +304,14 @@ platform_time(uint64_t nsec) {
 #endif
 
 static inline dispatch_time_t
-clock_and_value_to_time(int clock, long long deadline) {
+clock_and_value_to_time(int clock, long long sec, long long nsec) {
+  uint64_t deadline;
+  if (sec < 0 || (sec == 0 && nsec < 0))
+    deadline = 0;
+  else if (__builtin_mul_overflow(sec, NSEC_PER_SEC, &deadline)
+      || __builtin_add_overflow(nsec, deadline, &deadline)) {
+    deadline = UINT64_MAX;
+  }
   uint64_t value = platform_time((uint64_t)deadline);
   if (value >= DISPATCH_TIME_MAX_VALUE) {
     return DISPATCH_TIME_FOREVER;
@@ -304,6 +321,13 @@ clock_and_value_to_time(int clock, long long deadline) {
     return value;
   case swift_clock_id_continuous:
     return value | DISPATCH_UP_OR_MONOTONIC_TIME_MASK;
+  case swift_clock_id_wall: {
+    struct timespec ts = {
+      .tv_sec = static_cast<decltype(ts.tv_sec)>(sec),
+      .tv_nsec = static_cast<decltype(ts.tv_nsec)>(nsec)
+    };
+    return dispatch_walltime(&ts, 0);
+  }
   }
   __builtin_unreachable();
 }
@@ -332,18 +356,14 @@ void swift_dispatchEnqueueWithDeadline(bool global,
     job->schedulerPrivate[SwiftJobDispatchQueueIndex] = queue;
   }
 
-  uint64_t deadline;
-  if (__builtin_mul_overflow(sec, NSEC_PER_SEC, &deadline)
-      || __builtin_add_overflow(nsec, deadline, &deadline)) {
-    deadline = UINT64_MAX;
-  }
-
-  dispatch_time_t when = clock_and_value_to_time(clock, deadline);
+  dispatch_time_t when = clock_and_value_to_time(clock, sec, nsec);
 
   if (tnsec != -1) {
     uint64_t leeway;
-    if (__builtin_mul_overflow(tsec, NSEC_PER_SEC, &leeway)
-        || __builtin_add_overflow(tnsec, deadline, &leeway)) {
+    if (tsec < 0 || (tsec == 0 && tnsec < 0))
+      leeway = 0;
+    else if (__builtin_mul_overflow(tsec, NSEC_PER_SEC, &leeway)
+             || __builtin_add_overflow(tnsec, leeway, &leeway)) {
       leeway = UINT64_MAX;
     }
 
diff --git a/stdlib/public/Concurrency/DummyExecutor.swift b/stdlib/public/Concurrency/DummyExecutor.swift
deleted file mode 100644
index ec7bc7897198a..0000000000000
--- a/stdlib/public/Concurrency/DummyExecutor.swift
+++ /dev/null
@@ -1,63 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2020 - 2025 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import Swift
-
-// .. Main Executor ............................................................
-
-@available(SwiftStdlib 6.2, *)
-public final class DummyMainExecutor: MainExecutor, @unchecked Sendable {
-  public init() {}
-
-  public func run() throws {
-    fatalError("There is no executor implementation active")
-  }
-
-  public func stop() {
-    fatalError("There is no executor implementation active")
-  }
-
-  #if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  public func enqueue(_ job: UnownedJob) {
-    fatalError("There is no executor implementation active")
-  }
-  #else
-  public func enqueue(_ job: consuming ExecutorJob) {
-    fatalError("There is no executor implementation active")
-  }
-  #endif
-
-  public var isMainExecutor: Bool { true }
-
-  public func checkIsolated() {
-    // Do nothing
-  }
-}
-
-// .. Task Executor ............................................................
-
-@available(SwiftStdlib 6.2, *)
-public final class DummyTaskExecutor: TaskExecutor, @unchecked Sendable {
-  public init() {}
-
-  #if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  public func enqueue(_ job: UnownedJob) {
-    fatalError("There is no executor implementation active")
-  }
-  #else
-  public func enqueue(_ job: consuming ExecutorJob) {
-    fatalError("There is no executor implementation active")
-  }
-  #endif
-
-  public var isMainExecutor: Bool { false }
-}
diff --git a/stdlib/public/Concurrency/Executor.swift b/stdlib/public/Concurrency/Executor.swift
index af6991eda55e4..7a408c521d78e 100644
--- a/stdlib/public/Concurrency/Executor.swift
+++ b/stdlib/public/Concurrency/Executor.swift
@@ -26,25 +26,36 @@ public protocol Executor: AnyObject, Sendable {
   // Cannot introduce these methods in SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
   // since it lacks move-only type support.
   #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   @available(*, deprecated, message: "Implement 'enqueue(_: consuming ExecutorJob)' instead")
   func enqueue(_ job: consuming Job)
   #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 
   #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   func enqueue(_ job: consuming ExecutorJob)
   #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 
-  #if !$Embedded
+  #if os(WASI) || !$Embedded
   /// `true` if this is the main executor.
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   var isMainExecutor: Bool { get }
+  #endif // os(WASI) || !$Embedded
+
+  #if !$Embedded
+  /// Return this executable as a SchedulingExecutor, or nil if that is
+  /// unsupported.
+  ///
+  /// Executors that implement SchedulingExecutor should provide their
+  /// own copy of this method, which will allow the compiler to avoid a
+  /// potentially expensive runtime cast.
+  @available(StdlibDeploymentTarget 6.2, *)
+  var asSchedulingExecutor: (any SchedulingExecutor)? { get }
   #endif
 }
 
-@available(SwiftStdlib 6.2, *)
-public protocol SchedulableExecutor: Executor {
+@available(StdlibDeploymentTarget 6.2, *)
+public protocol SchedulingExecutor: Executor {
 
   #if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 
@@ -63,7 +74,7 @@ public protocol SchedulableExecutor: Executor {
   /// - tolerance: The maximum additional delay permissible before the
   ///              job is executed.  `nil` means no limit.
   /// - clock:     The clock used for the delay.
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   func enqueue<C: Clock>(_ job: consuming ExecutorJob,
                          after delay: C.Duration,
                          tolerance: C.Duration?,
@@ -82,8 +93,8 @@ public protocol SchedulableExecutor: Executor {
   ///              will not be executed before this time.
   /// - tolerance: The maximum additional delay permissible before the
   ///              job is executed.  `nil` means no limit.
-  /// - clock:     The clock used for the delay..
-  @available(SwiftStdlib 6.2, *)
+  /// - clock:     The clock used for the delay.
+  @available(StdlibDeploymentTarget 6.2, *)
   func enqueue<C: Clock>(_ job: consuming ExecutorJob,
                          at instant: C.Instant,
                          tolerance: C.Duration?,
@@ -93,17 +104,46 @@ public protocol SchedulableExecutor: Executor {
 
 }
 
+extension Actor {
+
+  /// Perform an operation with the actor's ``SerialExecutor``.
+  ///
+  /// This converts the actor's ``Actor/unownedExecutor`` to a ``SerialExecutor`` while
+  /// retaining the actor for the duration of the operation. This is to ensure the lifetime
+  /// of the executor while performing the operation.
+  @_alwaysEmitIntoClient
+  @available(SwiftStdlib 5.1, *)
+  public nonisolated func withSerialExecutor<T: ~Copyable, E: Error>(_ operation: (any SerialExecutor) throws(E) -> T) throws(E) -> T {
+    try operation(unsafe unsafeBitCast(self.unownedExecutor, to: (any SerialExecutor).self))
+  }
+
+  /// Perform an operation with the actor's ``SerialExecutor``.
+  ///
+  /// This converts the actor's ``Actor/unownedExecutor`` to a ``SerialExecutor`` while
+  /// retaining the actor for the duration of the operation. This is to ensure the lifetime
+  /// of the executor while performing the operation.
+  @_alwaysEmitIntoClient
+  @available(SwiftStdlib 5.1, *)
+  public nonisolated func withSerialExecutor<T: ~Copyable, E: Error>(_ operation: nonisolated(nonsending) (any SerialExecutor) async throws(E) -> T) async throws(E) -> T {
+    try await operation(unsafe unsafeBitCast(self.unownedExecutor, to: (any SerialExecutor).self))
+  }
+}
+
 extension Executor {
-  /// Return this executable as a SchedulableExecutor, or nil if that is
+
+  #if !$Embedded
+  /// Return this executor as a SchedulingExecutor, or nil if that is
   /// unsupported.
   ///
-  /// Executors that implement SchedulableExecutor should provide their
+  /// Executors that implement SchedulingExecutor should provide their
   /// own copy of this method, which will allow the compiler to avoid a
   /// potentially expensive runtime cast.
-  @available(SwiftStdlib 6.2, *)
-  var asSchedulable: SchedulableExecutor? {
-    return self as? SchedulableExecutor
+  @available(StdlibDeploymentTarget 6.2, *)
+  public var asSchedulingExecutor: (any SchedulingExecutor)? {
+    return self as? SchedulingExecutor
   }
+  #endif
+
 }
 
 extension Executor {
@@ -119,23 +159,22 @@ extension Executor where Self: Equatable {
 }
 
 extension Executor {
-
-  #if !$Embedded
+  #if os(WASI) || !$Embedded
   // This defaults to `false` so that existing third-party Executor
   // implementations will work as expected.
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public var isMainExecutor: Bool { false }
-  #endif
+  #endif // os(WASI) || !$Embedded
 
 }
 
 // Delay support
-@available(SwiftStdlib 6.2, *)
-extension SchedulableExecutor {
+@available(StdlibDeploymentTarget 6.2, *)
+extension SchedulingExecutor {
 
   #if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public func enqueue<C: Clock>(_ job: consuming ExecutorJob,
                                 after delay: C.Duration,
                                 tolerance: C.Duration? = nil,
@@ -146,7 +185,7 @@ extension SchedulableExecutor {
             tolerance: tolerance, clock: clock)
   }
 
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public func enqueue<C: Clock>(_ job: consuming ExecutorJob,
                                 at instant: C.Instant,
                                 tolerance: C.Duration? = nil,
@@ -250,7 +289,7 @@ public protocol SerialExecutor: Executor {
   // avoid drilling down to the base conformance just for the basic
   // work-scheduling operation.
   @_nonoverride
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   @available(*, deprecated, message: "Implement 'enqueue(_: consuming ExecutorJob)' instead")
   func enqueue(_ job: consuming Job)
   #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
@@ -261,7 +300,7 @@ public protocol SerialExecutor: Executor {
   // avoid drilling down to the base conformance just for the basic
   // work-scheduling operation.
   @_nonoverride
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   func enqueue(_ job: consuming ExecutorJob)
   #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 
@@ -292,7 +331,7 @@ public protocol SerialExecutor: Executor {
   /// - Returns: `true`, if `self` and the `other` executor actually are
   ///            mutually exclusive and it is safe–from a concurrency
   ///            perspective–to execute code assuming one on the other.
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   func isSameExclusiveExecutionContext(other: Self) -> Bool
 
   /// Last resort "fallback" isolation check, called when the concurrency runtime
@@ -315,23 +354,40 @@ public protocol SerialExecutor: Executor {
   ///
   /// - Warning: This method must crash and halt program execution if unable
   ///     to prove the isolation of the calling context.
-  @available(SwiftStdlib 6.0, *)
+  @available(StdlibDeploymentTarget 6.0, *)
   func checkIsolated()
 
-  @available(SwiftStdlib 6.2, *)
-  func isIsolatingCurrentContext() -> Bool
+  /// Checks if the current execution context is isolated by this executor.
+  ///
+  /// This function can be called by the runtime in order to perform assertions,
+  /// or attempt to issue warnings about unexpected isolation.
+  ///
+  /// This method will be invoked _before_ `checkIsolated` and may also be invoked
+  /// when crashing is not an acceptable outcome of a check (e.g. when attempting to issue isolation _warnings_).
+  ///
+  /// Implementations should prefer to implement this method rather than `checkIsolated()` since it can often
+  /// result in more tailored error messages. It is allowed, and useful for backwards compatibility with old
+  /// runtimes which are not able to invoke `isIsolatingCurrentContext()` to implement `checkIsolated()`,
+  /// even if an implementation is able to implement this method. Often times an implementation of `checkIsolated()`,
+  /// would then invoke `isIsolatingCurrentContext()` and crash if the returned value was `false`.
+  ///
+  /// The default implementation returns `nil` is used to indicate that it is "unknown" if the current context is
+  /// isolated by this serial executor. The runtime then _may_ proceed to invoke `checkIsolated()` as a last-resort
+  /// attempt to verify the isolation of the current context.
+  @available(StdlibDeploymentTarget 6.2, *)
+  func isIsolatingCurrentContext() -> Bool?
 
 }
 
-@available(SwiftStdlib 6.0, *)
+@available(StdlibDeploymentTarget 6.0, *)
 extension SerialExecutor {
 
-  #if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @available(SwiftStdlib 6.2, *)
+  #if os(WASI) || (!$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY)
+  @available(StdlibDeploymentTarget 6.2, *)
   public var isMainExecutor: Bool { return MainActor.executor._isSameExecutor(self) }
-  #endif
+  #endif // os(WASI) || (!$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY)
 
-  @available(SwiftStdlib 6.0, *)
+  @available(StdlibDeploymentTarget 6.0, *)
   public func checkIsolated() {
     #if !$Embedded
     fatalError("Unexpected isolation context, expected to be executing on \(Self.self)")
@@ -340,11 +396,26 @@ extension SerialExecutor {
     #endif
   }
 
-  @available(SwiftStdlib 6.2, *)
+  #if SWIFT_CONCURRENCY_USES_DISPATCH
+  @available(StdlibDeploymentTarget 6.2, *)
+  private var _dispatchQueue: OpaquePointer? {
+    return unsafe _getDispatchQueueForExecutor(self.asUnownedSerialExecutor())
+  }
+  #endif
+
+  @available(StdlibDeploymentTarget 6.2, *)
   internal func _isSameExecutor(_ rhs: some SerialExecutor) -> Bool {
     if rhs === self {
       return true
     }
+    #if SWIFT_CONCURRENCY_USES_DISPATCH
+    if let rhsQueue = unsafe rhs._dispatchQueue {
+      if let ourQueue = unsafe _dispatchQueue, ourQueue == rhsQueue {
+        return true
+      }
+      return false
+    }
+    #endif
     if let rhs = rhs as? Self {
       return isSameExclusiveExecutionContext(other: rhs)
     }
@@ -352,13 +423,12 @@ extension SerialExecutor {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension SerialExecutor {
 
-  @available(SwiftStdlib 6.2, *)
-  public func isIsolatingCurrentContext() -> Bool {
-    self.checkIsolated()
-    return true
+  @available(StdlibDeploymentTarget 6.2, *)
+  public func isIsolatingCurrentContext() -> Bool? {
+    return nil
   }
 }
 
@@ -379,7 +449,7 @@ extension SerialExecutor {
 /// the provided task executor.
 ///
 /// Unstructured tasks do not inherit the task executor.
-@available(SwiftStdlib 6.0, *)
+@available(StdlibDeploymentTarget 6.0, *)
 public protocol TaskExecutor: Executor {
   // This requirement is repeated here as a non-override so that we
   // get a redundant witness-table entry for it.  This allows us to
@@ -410,7 +480,7 @@ public protocol TaskExecutor: Executor {
   func asUnownedTaskExecutor() -> UnownedTaskExecutor
 }
 
-@available(SwiftStdlib 6.0, *)
+@available(StdlibDeploymentTarget 6.0, *)
 extension TaskExecutor {
   public func asUnownedTaskExecutor() -> UnownedTaskExecutor {
     unsafe UnownedTaskExecutor(ordinary: self)
@@ -418,7 +488,7 @@ extension TaskExecutor {
 }
 
 #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 extension Executor {
 
   // Delegation goes like this:
@@ -438,28 +508,28 @@ extension Executor {
 }
 #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 extension SerialExecutor {
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   public func asUnownedSerialExecutor() -> UnownedSerialExecutor {
     unsafe UnownedSerialExecutor(ordinary: self)
   }
 }
 
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 extension SerialExecutor {
 
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   public func isSameExclusiveExecutionContext(other: Self) -> Bool {
     return self === other
   }
 
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension SerialExecutor where Self: Equatable {
 
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public func isSameExclusiveExecutionContext(other: Self) -> Bool {
     return self == other
   }
@@ -471,7 +541,7 @@ extension SerialExecutor where Self: Equatable {
 /// The idea here is that some executors may work by running a loop
 /// that processes events of some sort; we want a way to enter that loop,
 /// and we would also like a way to trigger the loop to exit.
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 public protocol RunLoopExecutor: Executor {
   /// Run the executor's run loop.
   ///
@@ -502,7 +572,7 @@ public protocol RunLoopExecutor: Executor {
   func stop()
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension RunLoopExecutor {
 
   public func runUntil(_ condition: () -> Bool) throws {
@@ -512,40 +582,51 @@ extension RunLoopExecutor {
 }
 
 
-/// The main executor must conform to these three protocols; we have to
+/// The main executor must conform to these two protocols; we have to
 /// make this a protocol for compatibility with Embedded Swift.
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 public protocol MainExecutor: RunLoopExecutor, SerialExecutor {
 }
 
 
 /// An ExecutorFactory is used to create the default main and task
 /// executors.
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 public protocol ExecutorFactory {
-  #if !$Embedded
+  #if os(WASI) || !$Embedded
   /// Constructs and returns the main executor, which is started implicitly
   /// by the `async main` entry point and owns the "main" thread.
   static var mainExecutor: any MainExecutor { get }
-  #endif
+  #endif // os(WASI) || !$Embedded
 
   /// Constructs and returns the default or global executor, which is the
   /// default place in which we run tasks.
   static var defaultExecutor: any TaskExecutor { get }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
+typealias DefaultExecutorFactory = PlatformExecutorFactory
+
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_createExecutors")
 public func _createExecutors<F: ExecutorFactory>(factory: F.Type) {
-  #if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+  #if os(WASI) || (!$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY)
   MainActor._executor = factory.mainExecutor
-  #endif
+  #endif // os(WASI) || (!$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY)
   Task._defaultExecutor = factory.defaultExecutor
 }
 
-#if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+@available(SwiftStdlib 6.2, *)
+@_silgen_name("swift_createDefaultExecutors")
+func _createDefaultExecutors() {
+  if Task._defaultExecutor == nil {
+    _createExecutors(factory: DefaultExecutorFactory.self)
+  }
+}
+
+#if os(WASI) || (!$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY)
 extension MainActor {
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   static var _executor: (any MainExecutor)? = nil
 
   /// The main executor, which is started implicitly by the `async main`
@@ -553,18 +634,24 @@ extension MainActor {
   ///
   /// Attempting to set this after the first `enqueue` on the main
   /// executor is a fatal error.
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public static var executor: any MainExecutor {
-    if _executor == nil {
-      _executor = PlatformExecutorFactory.mainExecutor
-    }
+    // It would be good if there was a Swift way to do this
+    _createDefaultExecutorsOnce()
     return _executor!
   }
+
+  /// An unowned version of the above, for performance
+  @available(StdlibDeploymentTarget 6.2, *)
+  static var unownedExecutor: UnownedSerialExecutor {
+    _createDefaultExecutorsOnce()
+    return unsafe UnownedSerialExecutor(ordinary: _executor!)
+  }
 }
-#endif // !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+#endif // os(WASI) || (!$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY)
 
 extension Task where Success == Never, Failure == Never {
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   static var _defaultExecutor: (any TaskExecutor)? = nil
 
   /// The default or global executor, which is the default place in which
@@ -572,13 +659,19 @@ extension Task where Success == Never, Failure == Never {
   ///
   /// Attempting to set this after the first `enqueue` on the global
   /// executor is a fatal error.
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public static var defaultExecutor: any TaskExecutor {
-    if _defaultExecutor == nil {
-      _defaultExecutor = PlatformExecutorFactory.defaultExecutor
-    }
+    // It would be good if there was a Swift way to do this
+    _createDefaultExecutorsOnce()
     return _defaultExecutor!
   }
+
+  /// An unowned version of the above, for performance
+  @available(StdlibDeploymentTarget 6.2, *)
+  static var unownedDefaultExecutor: UnownedTaskExecutor {
+    _createDefaultExecutorsOnce()
+    return unsafe UnownedTaskExecutor(_defaultExecutor!)
+  }
 }
 
 extension Task where Success == Never, Failure == Never {
@@ -593,7 +686,7 @@ extension Task where Success == Never, Failure == Never {
   ///   3. The task executor for the current thread
   ///
   ///  If none of these exist, returns the default executor.
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   @_unavailableInEmbedded
   public static var currentExecutor: any Executor {
     if let activeExecutor = unsafe _getActiveExecutor().asSerialExecutor() {
@@ -607,7 +700,7 @@ extension Task where Success == Never, Failure == Never {
   }
 
   /// Get the preferred executor for the current `Task`, if any.
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public static var preferredExecutor: (any TaskExecutor)? {
     if let taskExecutor = unsafe _getPreferredTaskExecutor().asTaskExecutor() {
       return taskExecutor
@@ -615,30 +708,32 @@ extension Task where Success == Never, Failure == Never {
     return nil
   }
 
-  /// Get the current *schedulable* executor, if any.
+  #if !$Embedded
+  /// Get the current *scheduling* executor, if any.
   ///
   /// This follows the same logic as `currentExecutor`, except that it ignores
-  /// any executor that isn't a `SchedulableExecutor`.
-  @available(SwiftStdlib 6.2, *)
-  @_unavailableInEmbedded
-  public static var currentSchedulableExecutor: (any SchedulableExecutor)? {
+  /// any executor that isn't a `SchedulingExecutor`.
+  @available(StdlibDeploymentTarget 6.2, *)
+  public static var currentSchedulingExecutor: (any SchedulingExecutor)? {
     if let activeExecutor = unsafe _getActiveExecutor().asSerialExecutor(),
-       let schedulable = activeExecutor.asSchedulable {
-      return schedulable
+       let scheduling = activeExecutor.asSchedulingExecutor {
+      return scheduling
     }
     if let taskExecutor = unsafe _getPreferredTaskExecutor().asTaskExecutor(),
-       let schedulable = taskExecutor.asSchedulable {
-      return schedulable
+       let scheduling = taskExecutor.asSchedulingExecutor {
+      return scheduling
     }
     if let taskExecutor = unsafe _getCurrentTaskExecutor().asTaskExecutor(),
-       let schedulable = taskExecutor.asSchedulable {
-      return schedulable
+       let scheduling = taskExecutor.asSchedulingExecutor {
+      return scheduling
     }
-    if let schedulable = defaultExecutor.asSchedulable {
-      return schedulable
+    if let scheduling = defaultExecutor.asSchedulingExecutor {
+      return scheduling
     }
     return nil
   }
+  #endif
+
 }
 
 
@@ -711,14 +806,14 @@ public struct UnownedSerialExecutor: Sendable {
     unsafe _executor_isComplexEquality(self)
   }
 
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public func asSerialExecutor() -> (any SerialExecutor)? {
     return unsafe unsafeBitCast(executor, to: (any SerialExecutor)?.self)
   }
 }
 
 
-@available(SwiftStdlib 6.0, *)
+@available(StdlibDeploymentTarget 6.0, *)
 @unsafe
 @frozen
 public struct UnownedTaskExecutor: Sendable {
@@ -742,13 +837,13 @@ public struct UnownedTaskExecutor: Sendable {
     unsafe self.executor = Builtin.buildOrdinaryTaskExecutorRef(executor)
   }
 
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   @inlinable
   public init<E: TaskExecutor>(_ executor: __shared E) {
     unsafe self.executor = Builtin.buildOrdinaryTaskExecutorRef(executor)
   }
 
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public func asTaskExecutor() -> (any TaskExecutor)? {
     return unsafe unsafeBitCast(executor, to: (any TaskExecutor)?.self)
   }
@@ -811,7 +906,7 @@ func _checkExpectedExecutor(_filenameStart: Builtin.RawPointer,
 /// otherwise returns only the job's 32bit Id.
 ///
 /// - Returns: the Id stored in this ExecutorJob or Task, for purposes of debug printing
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 @_silgen_name("swift_task_getJobTaskId")
 internal func _getJobTaskId(_ job: UnownedJob) -> UInt64
 
@@ -831,9 +926,13 @@ internal func _task_serialExecutor_checkIsolated<E>(executor: E)
 
 @available(SwiftStdlib 6.2, *)
 @_silgen_name("_task_serialExecutor_isIsolatingCurrentContext")
-internal func _task_serialExecutor_isIsolatingCurrentContext<E>(executor: E) -> Bool
-    where E: SerialExecutor {
-  return executor.isIsolatingCurrentContext()
+internal func _task_serialExecutor_isIsolatingCurrentContext<E>(executor: E) -> Int8
+  where E: SerialExecutor {
+  switch executor.isIsolatingCurrentContext() {
+  case nil: -1 // unknown
+  case .some(false): 0 // not isolated
+  case .some(true): 1 // isolated!
+  }
 }
 
 /// Obtain the executor ref by calling the executor's `asUnownedSerialExecutor()`.
@@ -855,21 +954,36 @@ internal func _task_taskExecutor_getTaskExecutorRef<E>(_ taskExecutor: E) -> Bui
   return unsafe taskExecutor.asUnownedTaskExecutor().executor
 }
 
+#if $Embedded
+@_silgen_name("_swift_task_enqueueOnExecutor")
+internal func _enqueueOnExecutor(job unownedJob: UnownedJob, executor: any SerialExecutor) {
+  #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+  if #available(StdlibDeploymentTarget 5.9, *) {
+    executor.enqueue(ExecutorJob(context: unownedJob._context))
+  } else {
+    fatalError("we shouldn't get here; if we have, availability is broken")
+  }
+  #else // SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+  executor.enqueue(unownedJob)
+  #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+}
+#else
 // Used by the concurrency runtime
 @available(SwiftStdlib 5.1, *)
 @_silgen_name("_swift_task_enqueueOnExecutor")
 internal func _enqueueOnExecutor<E>(job unownedJob: UnownedJob, executor: E)
 where E: SerialExecutor {
   #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  if #available(SwiftStdlib 5.9, *) {
+  if #available(StdlibDeploymentTarget 5.9, *) {
     executor.enqueue(ExecutorJob(context: unownedJob._context))
   } else {
-    executor.enqueue(unownedJob)
+    fatalError("we shouldn't get here; if we have, availability is broken")
   }
   #else // SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
   executor.enqueue(unownedJob)
   #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 }
+#endif // #if $Embedded
 
 @_unavailableInEmbedded
 @available(SwiftStdlib 6.0, *)
diff --git a/stdlib/public/Concurrency/ExecutorAssertions.swift b/stdlib/public/Concurrency/ExecutorAssertions.swift
index 79143faad9c62..8c58cdb624910 100644
--- a/stdlib/public/Concurrency/ExecutorAssertions.swift
+++ b/stdlib/public/Concurrency/ExecutorAssertions.swift
@@ -81,10 +81,10 @@ extension Actor {
   /// * In `-O` builds (the default for Xcode's Release configuration), stops
   ///   program execution.
   ///
-  /// - Note: This check is performed against the actor's serial executor,
-  ///   meaning that / if another actor uses the same serial executor--by using
+  /// - Note: Because this check is performed against the actor's serial executor,
+  ///   if another actor uses the same serial executor--by using
   ///   that actor's serial executor as its own ``Actor/unownedExecutor``--this
-  ///   check will succeed , as from a concurrency safety perspective, the
+  ///   check will succeed.  From a concurrency safety perspective, the
   ///   serial executor guarantees mutual exclusion of those two actors.
   ///
   /// - Parameters:
diff --git a/stdlib/public/Concurrency/ExecutorBridge.cpp b/stdlib/public/Concurrency/ExecutorBridge.cpp
index 6debd5659beb8..f5cb5a8280401 100644
--- a/stdlib/public/Concurrency/ExecutorBridge.cpp
+++ b/stdlib/public/Concurrency/ExecutorBridge.cpp
@@ -14,8 +14,11 @@
 #include <dispatch/dispatch.h>
 #endif
 
+#include "swift/Threading/Once.h"
+
 #include "Error.h"
 #include "ExecutorBridge.h"
+#include "TaskPrivate.h"
 
 using namespace swift;
 
@@ -27,6 +30,13 @@ void _swift_exit(int result) {
   exit(result);
 }
 
+extern "C" SWIFT_CC(swift)
+void swift_createDefaultExecutorsOnce() {
+  static swift::once_t createExecutorsOnce;
+
+  swift::once(createExecutorsOnce, swift_createDefaultExecutors);
+}
+
 #if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 extern "C" SWIFT_CC(swift)
 SerialExecutorRef swift_getMainExecutor() {
@@ -34,86 +44,19 @@ SerialExecutorRef swift_getMainExecutor() {
 }
 #endif
 
-extern "C" SWIFT_CC(swift)
-void _swift_task_checkIsolatedSwift(
-  HeapObject *executor,
-  const Metadata *executorType,
-  const SerialExecutorWitnessTable *witnessTable
-);
-
 extern "C" SWIFT_CC(swift)
 void _swift_task_checkIsolatedSwift(HeapObject *executor,
                                     const Metadata *executorType,
                                     const SerialExecutorWitnessTable *witnessTable);
 
 extern "C" SWIFT_CC(swift)
-bool _swift_task_isIsolatingCurrentContextSwift(
-  HeapObject *executor,
-  const Metadata *executorType,
-  const SerialExecutorWitnessTable *witnessTable
-);
-
-extern "C" SWIFT_CC(swift)
-bool _swift_task_isMainExecutorSwift(
-  HeapObject *executor,
-  const Metadata *executorType,
-  const SerialExecutorWitnessTable *witnessTable
-);
-
-extern "C" SWIFT_CC(swift)
-void swift_task_checkIsolatedImpl(SerialExecutorRef executor) {
-  HeapObject *identity = executor.getIdentity();
-
-  // We might be being called with an actor rather than a "proper"
-  // SerialExecutor; in that case, we won't have a SerialExecutor witness
-  // table.
-  if (executor.hasSerialExecutorWitnessTable()) {
-    _swift_task_checkIsolatedSwift(identity,
-                                   swift_getObjectType(identity),
-                                   executor.getSerialExecutorWitnessTable());
-  } else {
-    const Metadata *objectType = swift_getObjectType(executor.getIdentity());
-    auto typeName = swift_getTypeName(objectType, true);
-
-    swift_Concurrency_fatalError(
-      0, "Incorrect actor executor assumption; expected '%.*s' executor.\n",
-      (int)typeName.length, typeName.data);
-  }
-}
-
-extern "C" SWIFT_CC(swift)
-bool swift_task_isIsolatingCurrentContextImpl(SerialExecutorRef executor) {
-  HeapObject *identity = executor.getIdentity();
-
-  // We might be being called with an actor rather than a "proper"
-  // SerialExecutor; in that case, we won't have a SerialExecutor witness
-  // table.
-  if (executor.hasSerialExecutorWitnessTable()) {
-    return _swift_task_isIsolatingCurrentContextSwift(identity,
-                                   swift_getObjectType(identity),
-                                   executor.getSerialExecutorWitnessTable());
-  } else {
-    const Metadata *objectType = swift_getObjectType(executor.getIdentity());
-    auto typeName = swift_getTypeName(objectType, true);
-
-    swift_Concurrency_fatalError(
-      0, "Incorrect actor executor assumption; expected '%.*s' executor.\n",
-      (int)typeName.length, typeName.data);
-  }
-}
-
-extern "C" SWIFT_CC(swift)
-bool swift_task_isMainExecutorImpl(SerialExecutorRef executor) {
-  HeapObject *identity = executor.getIdentity();
-  return executor.hasSerialExecutorWitnessTable()
-    && _swift_task_isMainExecutorSwift(identity,
-                                       swift_getObjectType(identity),
-                                       executor.getSerialExecutorWitnessTable());
+uint8_t swift_job_getPriority(Job *job) {
+  return (uint8_t)(job->getPriority());
 }
 
 extern "C" SWIFT_CC(swift)
-uint8_t swift_job_getPriority(Job *job) {
-  return (uint8_t)(job->getPriority());
+void swift_job_setPriority(Job *job, uint8_t priority) {
+  job->setPriority(JobPriority(priority));
 }
 
 extern "C" SWIFT_CC(swift)
@@ -136,6 +79,15 @@ extern "C" SWIFT_CC(swift)
 void swift_dispatchAssertMainQueue() {
   dispatch_assert_queue(dispatch_get_main_queue());
 }
-#endif // SWIFT_CONCURRENCY_ENABLE_DISPATCH
+
+extern "C" SWIFT_CC(swift)
+void *swift_getDispatchQueueForExecutor(SerialExecutorRef executor) {
+  if (executor.getRawImplementation() == (uintptr_t)_swift_task_getDispatchQueueSerialExecutorWitnessTable()) {
+    return executor.getIdentity();
+  }
+  return nullptr;
+}
+
+#endif // SWIFT_CONCURRENCY_USES_DISPATCH
 
 #pragma clang diagnostic pop
diff --git a/stdlib/public/Concurrency/ExecutorBridge.h b/stdlib/public/Concurrency/ExecutorBridge.h
index aa2f720eb264f..1849495dc6498 100644
--- a/stdlib/public/Concurrency/ExecutorBridge.h
+++ b/stdlib/public/Concurrency/ExecutorBridge.h
@@ -23,6 +23,9 @@ namespace swift {
 extern "C" SWIFT_CC(swift)
 SerialExecutorRef swift_getMainExecutor();
 
+extern "C" SWIFT_CC(swift)
+TaskExecutorRef swift_getDefaultExecutor();
+
 #if !SWIFT_CONCURRENCY_EMBEDDED
 extern "C" SWIFT_CC(swift)
 void *swift_createDispatchEventC(void (*handler)(void *), void *context);
@@ -33,10 +36,16 @@ void swift_destroyDispatchEventC(void *event);
 extern "C" SWIFT_CC(swift)
 void swift_signalDispatchEvent(void *event);
 #endif // !SWIFT_CONCURRENCY_EMBEDDED
- 
+
 extern "C" SWIFT_CC(swift) __attribute__((noreturn))
 void swift_dispatchMain();
 
+extern "C" SWIFT_CC(swift)
+void swift_createDefaultExecutors();
+
+extern "C" SWIFT_CC(swift)
+void swift_createDefaultExecutorsOnce();
+
 #pragma clang diagnostic pop
 
 } // namespace swift
diff --git a/stdlib/public/Concurrency/ExecutorBridge.swift b/stdlib/public/Concurrency/ExecutorBridge.swift
index 9301de71d43e3..c52798bd80e34 100644
--- a/stdlib/public/Concurrency/ExecutorBridge.swift
+++ b/stdlib/public/Concurrency/ExecutorBridge.swift
@@ -17,96 +17,114 @@
 
 import Swift
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("_swift_exit")
 internal func _exit(result: CInt)
 
 #if !$Embedded
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("_swift_task_isMainExecutorSwift")
 internal func _isMainExecutor<E>(_ executor: E) -> Bool where E: SerialExecutor {
   return executor.isMainExecutor
 }
 #endif
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("_swift_task_checkIsolatedSwift")
 internal func checkIsolated<E>(executor: E) where E: SerialExecutor {
   executor.checkIsolated()
 }
 
-@available(SwiftStdlib 6.2, *)
+/// Invokes the swift function isIsolatingCurrentContext on the given executor,
+/// and converts between the `Optional<Bool>` into:
+///     -1: unknown
+///      0: not isolated
+///      1: isolated
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("_swift_task_isIsolatingCurrentContextSwift")
-internal func isIsolatingCurrentContext<E>(executor: E) -> Bool
-  where E: SerialExecutor
-{
-  return executor.isIsolatingCurrentContext()
+internal func isIsolatingCurrentContext<E>(executor: E) -> Int8
+  where E: SerialExecutor {
+  switch executor.isIsolatingCurrentContext() {
+  case nil: -1 // unknown
+  case .some(false): 0 // not isolated
+  case .some(true): 1 // isolated!
+  }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("_swift_getActiveExecutor")
 internal func _getActiveExecutor() -> UnownedSerialExecutor
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("_swift_getCurrentTaskExecutor")
 internal func _getCurrentTaskExecutor() -> UnownedTaskExecutor
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("_swift_getPreferredTaskExecutor")
 internal func _getPreferredTaskExecutor() -> UnownedTaskExecutor
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_job_allocate")
 internal func _jobAllocate(_ job: Builtin.Job,
                            _ capacity: Int) -> UnsafeMutableRawPointer
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_job_deallocate")
 internal func _jobDeallocate(_ job: Builtin.Job,
                              _ address: UnsafeMutableRawPointer)
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_job_getPriority")
 internal func _jobGetPriority(_ job: Builtin.Job) -> UInt8
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
+@_silgen_name("swift_job_setPriority")
+internal func _jobSetPriority(_ job: Builtin.Job, _ priority: UInt8)
+
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_job_getKind")
 internal func _jobGetKind(_ job: Builtin.Job) -> UInt8
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_job_getExecutorPrivateData")
 internal func _jobGetExecutorPrivateData(
   _ job: Builtin.Job
 ) -> UnsafeMutableRawPointer
 
-#if !$Embedded
+#if os(WASI) || !$Embedded
 #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_getMainExecutor")
-internal func _getMainExecutor() -> any SerialExecutor {
-  return MainActor.executor
+internal func _getMainExecutorAsSerialExecutor() -> UnownedSerialExecutor {
+  return unsafe MainActor.unownedExecutor
 }
 #else
 // For task-to-thread model, this is implemented in C++
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_getMainExecutor")
-internal func _getMainExecutor() -> any SerialExecutor
+internal func _getMainExecutorAsSerialExecutor() -> UnownedSerialExecutor
 #endif // SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-#endif // !$Embedded
+#endif // os(WASI) || !$Embedded
+
+@available(StdlibDeploymentTarget 6.2, *)
+@_silgen_name("swift_getDefaultExecutor")
+internal func _getDefaultExecutorAsTaskExecutor() -> UnownedTaskExecutor {
+  return unsafe Task.unownedDefaultExecutor
+}
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_dispatchMain")
 internal func _dispatchMain()
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_dispatchEnqueueMain")
 internal func _dispatchEnqueueMain(_ job: UnownedJob)
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_dispatchEnqueueGlobal")
 internal func _dispatchEnqueueGlobal(_ job: UnownedJob)
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_dispatchEnqueueWithDeadline")
 internal func _dispatchEnqueueWithDeadline(_ global: CBool,
                                            _ sec: CLongLong,
@@ -116,6 +134,14 @@ internal func _dispatchEnqueueWithDeadline(_ global: CBool,
                                            _ clock: CInt,
                                            _ job: UnownedJob)
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 @_silgen_name("swift_dispatchAssertMainQueue")
 internal func _dispatchAssertMainQueue()
+
+@_silgen_name("swift_createDefaultExecutorsOnce")
+func _createDefaultExecutorsOnce()
+
+@_silgen_name("swift_getDispatchQueueForExecutor")
+internal func _getDispatchQueueForExecutor(
+  _ executor: UnownedSerialExecutor
+) -> OpaquePointer?
diff --git a/stdlib/public/Concurrency/ExecutorImpl.cpp b/stdlib/public/Concurrency/ExecutorImpl.cpp
new file mode 100644
index 0000000000000..74bc4c13987d4
--- /dev/null
+++ b/stdlib/public/Concurrency/ExecutorImpl.cpp
@@ -0,0 +1,88 @@
+//===--- ExecutorImpl.cpp - C++ side of executor impl ---------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#if SWIFT_CONCURRENCY_USES_DISPATCH
+#include <dispatch/dispatch.h>
+#endif
+
+#include "Error.h"
+#include "ExecutorBridge.h"
+
+using namespace swift;
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
+
+
+extern "C" SWIFT_CC(swift)
+void _swift_task_checkIsolatedSwift(
+  HeapObject *executor,
+  const Metadata *executorType,
+  const SerialExecutorWitnessTable *witnessTable
+);
+
+extern "C" SWIFT_CC(swift) bool _swift_task_isMainExecutorSwift(
+    HeapObject *executor, const Metadata *executorType,
+    const SerialExecutorWitnessTable *witnessTable);
+
+extern "C" SWIFT_CC(swift) void swift_task_checkIsolatedImpl(
+    SerialExecutorRef executor) {
+  HeapObject *identity = executor.getIdentity();
+
+  // We might be being called with an actor rather than a "proper"
+  // SerialExecutor; in that case, we won't have a SerialExecutor witness
+  // table.
+  if (executor.hasSerialExecutorWitnessTable()) {
+    _swift_task_checkIsolatedSwift(identity, swift_getObjectType(identity),
+                                   executor.getSerialExecutorWitnessTable());
+  } else {
+    const Metadata *objectType = swift_getObjectType(executor.getIdentity());
+    auto typeName = swift_getTypeName(objectType, true);
+
+    swift_Concurrency_fatalError(
+        0, "Incorrect actor executor assumption; expected '%.*s' executor.\n",
+        (int)typeName.length, typeName.data);
+  }
+}
+
+
+extern "C" SWIFT_CC(swift)
+int8_t _swift_task_isIsolatingCurrentContextSwift(
+  HeapObject *executor,
+  const Metadata *executorType,
+  const SerialExecutorWitnessTable *witnessTable
+);
+
+extern "C" SWIFT_CC(swift) int8_t
+swift_task_isIsolatingCurrentContextImpl(
+    SerialExecutorRef executor) {
+  HeapObject *identity = executor.getIdentity();
+
+  // We might be being called with an actor rather than a "proper"
+  // SerialExecutor; in that case, we won't have a SerialExecutor witness
+  // table.
+  if (!executor.hasSerialExecutorWitnessTable())
+    return static_cast<uint8_t>(IsIsolatingCurrentContextDecision::Unknown);
+
+  return _swift_task_isIsolatingCurrentContextSwift(
+      identity, swift_getObjectType(identity),
+      executor.getSerialExecutorWitnessTable());
+}
+
+extern "C" SWIFT_CC(swift) bool swift_task_isMainExecutorImpl(
+    SerialExecutorRef executor) {
+  HeapObject *identity = executor.getIdentity();
+  return executor.hasSerialExecutorWitnessTable() &&
+         _swift_task_isMainExecutorSwift(
+             identity, swift_getObjectType(identity),
+             executor.getSerialExecutorWitnessTable());
+}
diff --git a/stdlib/public/Concurrency/ExecutorImpl.h b/stdlib/public/Concurrency/ExecutorImpl.h
index a068c456b3c05..44fb28a904581 100644
--- a/stdlib/public/Concurrency/ExecutorImpl.h
+++ b/stdlib/public/Concurrency/ExecutorImpl.h
@@ -227,9 +227,14 @@ swift_executor_invokeSwiftCheckIsolated(SwiftExecutorRef executor) {
 }
 
 /// Check if the current context is isolated by the specified executor.
-static inline bool
+///
+/// The numeric values correspond to `swift::IsIsolatingCurrentContextDecision`.
+///
+/// Specifically ONLY `1` means "isolated", while smaller values mean not isolated or unknown.
+/// See ``IsIsolatingCurrentContextDecision`` for details.
+static inline int8_t
 swift_executor_invokeSwiftIsIsolatingCurrentContext(SwiftExecutorRef executor) {
-  extern bool _swift_task_invokeSwiftIsIsolatingCurrentContext_c(SwiftExecutorRef executor);
+  extern int8_t _swift_task_invokeSwiftIsIsolatingCurrentContext_c(SwiftExecutorRef executor);
 
   return _swift_task_invokeSwiftIsIsolatingCurrentContext_c(executor);
 }
@@ -292,7 +297,8 @@ SWIFT_CC(swift) void swift_task_enqueueMainExecutorImpl(SwiftJob * _Nonnull job)
 SWIFT_CC(swift) void swift_task_checkIsolatedImpl(SwiftExecutorRef executor);
 
 /// Check if the specified executor isolates the current context.
-SWIFT_CC(swift) bool swift_task_isIsolatingCurrentContextImpl(SwiftExecutorRef executor);
+SWIFT_CC(swift) int8_t
+  swift_task_isIsolatingCurrentContextImpl(SwiftExecutorRef executor);
 
 /// Get a reference to the main executor.
 SWIFT_CC(swift) SwiftExecutorRef swift_task_getMainExecutorImpl(void);
diff --git a/stdlib/public/Concurrency/ExecutorImpl.swift b/stdlib/public/Concurrency/ExecutorImpl.swift
index 29a2438aa3ec0..52ed84d0f71ef 100644
--- a/stdlib/public/Concurrency/ExecutorImpl.swift
+++ b/stdlib/public/Concurrency/ExecutorImpl.swift
@@ -47,7 +47,7 @@ internal func donateToGlobalExecutor(
 @available(SwiftStdlib 6.2, *)
 @_silgen_name("swift_task_getMainExecutorImpl")
 internal func getMainExecutor() -> UnownedSerialExecutor {
-  return unsafe _getMainExecutor().asUnownedSerialExecutor()
+  return unsafe _getMainExecutorAsSerialExecutor()
 }
 
 @available(SwiftStdlib 6.2, *)
@@ -72,9 +72,9 @@ internal func enqueueOnGlobalExecutor(job unownedJob: UnownedJob) {
 internal func enqueueOnGlobalExecutor(delay: CUnsignedLongLong,
                                       job unownedJob: UnownedJob) {
   #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  Task.defaultExecutor.asSchedulable!.enqueue(ExecutorJob(unownedJob),
-                                              after: .nanoseconds(delay),
-                                              clock: .continuous)
+  Task.defaultExecutor.asSchedulingExecutor!.enqueue(ExecutorJob(unownedJob),
+                                                     after: .nanoseconds(delay),
+                                                     clock: .continuous)
   #else
   fatalError("swift_task_enqueueGlobalWithDelay() not supported for task-to-thread")
   #endif
@@ -93,15 +93,15 @@ internal func enqueueOnGlobalExecutor(seconds: CLongLong,
   let leeway = Duration.seconds(leewaySeconds) + Duration.nanoseconds(leewayNanoseconds)
   switch clock {
     case _ClockID.suspending.rawValue:
-      Task.defaultExecutor.asSchedulable!.enqueue(ExecutorJob(unownedJob),
-                                                  after: delay,
-                                                  tolerance: leeway,
-                                                  clock: .suspending)
+      Task.defaultExecutor.asSchedulingExecutor!.enqueue(ExecutorJob(unownedJob),
+                                                         after: delay,
+                                                         tolerance: leeway,
+                                                         clock: .suspending)
     case _ClockID.continuous.rawValue:
-      Task.defaultExecutor.asSchedulable!.enqueue(ExecutorJob(unownedJob),
-                                                  after: delay,
-                                                  tolerance: leeway,
-                                                  clock: .continuous)
+      Task.defaultExecutor.asSchedulingExecutor!.enqueue(ExecutorJob(unownedJob),
+                                                         after: delay,
+                                                         tolerance: leeway,
+                                                         clock: .continuous)
     default:
       fatalError("Unknown clock ID \(clock)")
   }
diff --git a/stdlib/public/Concurrency/GlobalConcurrentExecutor.swift b/stdlib/public/Concurrency/GlobalConcurrentExecutor.swift
index 7c876a99472d1..c8e0a0a4a54db 100644
--- a/stdlib/public/Concurrency/GlobalConcurrentExecutor.swift
+++ b/stdlib/public/Concurrency/GlobalConcurrentExecutor.swift
@@ -31,14 +31,13 @@ import Swift
 ///
 /// Customizing the global concurrent executor is currently not supported.
 @available(SwiftStdlib 6.0, *)
-@available(*, deprecated, renamed: "Task.defaultExecutor")
 @_unavailableInEmbedded
 public var globalConcurrentExecutor: any TaskExecutor {
   get {
-    if #available(SwiftStdlib 6.2, *) {
+    if #available(StdlibDeploymentTarget 6.2, *) {
       return Task.defaultExecutor
     } else {
-      return _DefaultGlobalConcurrentExecutor.shared
+      fatalError("we shouldn't get here; if we have, availability is broken")
     }
   }
 }
diff --git a/stdlib/public/Concurrency/GlobalExecutor.cpp b/stdlib/public/Concurrency/GlobalExecutor.cpp
index 833abb1a02f15..788ee0afeecc3 100644
--- a/stdlib/public/Concurrency/GlobalExecutor.cpp
+++ b/stdlib/public/Concurrency/GlobalExecutor.cpp
@@ -88,25 +88,31 @@ extern "C" bool _swift_task_invokeSwiftCheckIsolated_c(SwiftExecutorRef executor
 
 
 extern "C" SWIFT_CC(swift)
-bool _task_serialExecutor_isIsolatingCurrentContext(
+int8_t _task_serialExecutor_isIsolatingCurrentContext(
     HeapObject *executor,
     const Metadata *selfType,
     const SerialExecutorWitnessTable *wtable);
 
-SWIFT_CC(swift)
-bool swift::swift_task_invokeSwiftIsIsolatingCurrentContext(SerialExecutorRef executor)
+SWIFT_CC(swift) int8_t
+swift::swift_task_invokeSwiftIsIsolatingCurrentContext(SerialExecutorRef executor)
 {
-  if (!executor.hasSerialExecutorWitnessTable())
-    return false;
+  if (!executor.hasSerialExecutorWitnessTable()) {
+    return static_cast<int8_t>(IsIsolatingCurrentContextDecision::NotIsolated);
+  }
 
-  return _task_serialExecutor_isIsolatingCurrentContext(
+  auto decision = _task_serialExecutor_isIsolatingCurrentContext(
         executor.getIdentity(), swift_getObjectType(executor.getIdentity()),
         executor.getSerialExecutorWitnessTable());
+
+  return decision;
 }
 
-extern "C" bool _swift_task_invokeSwiftIsIsolatingCurrentContext_c(SwiftExecutorRef executor)
+extern "C" int8_t
+_swift_task_invokeSwiftIsIsolatingCurrentContext_c(SwiftExecutorRef executor)
 {
-  return swift_task_invokeSwiftIsIsolatingCurrentContext(*reinterpret_cast<SerialExecutorRef *>(&executor));
+  return
+      static_cast<int8_t>(swift_task_invokeSwiftIsIsolatingCurrentContext(
+      *reinterpret_cast<SerialExecutorRef *>(&executor)));
 }
 
 extern "C" void _swift_job_run_c(SwiftJob *job, SwiftExecutorRef executor)
@@ -155,6 +161,27 @@ extern "C" void swift_job_dealloc(SwiftJob *job, void *ptr) {
   return _swift_task_dealloc_specific(task, ptr);
 }
 
+IsIsolatingCurrentContextDecision
+swift::getIsIsolatingCurrentContextDecisionFromInt(int8_t value) {
+  switch (value) {
+  case -1: return IsIsolatingCurrentContextDecision::Unknown;
+  case 0: return IsIsolatingCurrentContextDecision::NotIsolated;
+  case 1: return IsIsolatingCurrentContextDecision::Isolated;
+  default:
+    swift_Concurrency_fatalError(0, "Unexpected IsIsolatingCurrentContextDecision value");
+  }
+}
+
+StringRef
+swift::getIsIsolatingCurrentContextDecisionNameStr(IsIsolatingCurrentContextDecision decision) {
+  switch (decision) {
+  case IsIsolatingCurrentContextDecision::Unknown: return "Unknown";
+  case IsIsolatingCurrentContextDecision::NotIsolated: return "NotIsolated";
+  case IsIsolatingCurrentContextDecision::Isolated: return "Isolated";
+  }
+  swift_Concurrency_fatalError(0, "Unexpected IsIsolatingCurrentContextDecision value");
+}
+
 /*****************************************************************************/
 /****************************** MAIN EXECUTOR  *******************************/
 /*****************************************************************************/
diff --git a/stdlib/public/Concurrency/MainActor.swift b/stdlib/public/Concurrency/MainActor.swift
index cddb4f83162b6..3f57abe877171 100644
--- a/stdlib/public/Concurrency/MainActor.swift
+++ b/stdlib/public/Concurrency/MainActor.swift
@@ -12,7 +12,7 @@
 
 import Swift
 
-#if !$Embedded
+#if os(WASI) || !$Embedded
 
 #if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 @available(SwiftStdlib 5.1, *)
@@ -162,6 +162,39 @@ extension MainActor {
     try assumeIsolated(operation, file: file, line: line)
   }
 }
+
+#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS)
+@_extern(c, "pthread_main_np")
+@usableFromInline
+internal func pthread_main_np() -> CInt
+
+@available(SwiftStdlib 5.1, *)
+@_alwaysEmitIntoClient
+@_silgen_name("swift_task_deinitOnExecutorMainActorBackDeploy")
+public func _deinitOnExecutorMainActorBackDeploy(
+  _ object: __owned AnyObject,
+  _ work: @convention(thin) (__owned AnyObject) -> Void,
+  _ executor: Builtin.Executor,
+  _ flags: Builtin.Word) {
+  if #available(macOS 15.4, iOS 18.4, watchOS 11.4, tvOS 18.4, visionOS 2.4, *) {
+    // On new-enough platforms, use the runtime functionality, which allocates
+    // the task more efficiently.
+    _deinitOnExecutor(object, work, executor, flags)
+  } else if pthread_main_np() == 1 {
+    // Using "main thread" as a proxy for "main actor", immediately destroy
+    // the object.
+    work(consume object)
+  } else {
+    // Steal the local object so that the reference count stays at 1 even when
+    // the object is captured.
+    var stolenObject: AnyObject? = consume object
+    Task.detached { @MainActor in
+      work(stolenObject.take()!)
+    }
+  }
+}
+#endif
+
 #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 
-#endif // !$Embedded
+#endif // os(WASI) || !$Embedded
diff --git a/stdlib/public/Concurrency/PartialAsyncTask.swift b/stdlib/public/Concurrency/PartialAsyncTask.swift
index d6bda0880db0a..a255d34d3454a 100644
--- a/stdlib/public/Concurrency/PartialAsyncTask.swift
+++ b/stdlib/public/Concurrency/PartialAsyncTask.swift
@@ -33,14 +33,14 @@ internal func _swiftJobRun(_ job: UnownedJob,
                            _ executor: UnownedSerialExecutor) -> ()
 
 @_unavailableInEmbedded
-@available(SwiftStdlib 6.0, *)
+@available(StdlibDeploymentTarget 6.0, *)
 @_silgen_name("swift_job_run_on_task_executor")
 @usableFromInline
 internal func _swiftJobRunOnTaskExecutor(_ job: UnownedJob,
                                          _ executor: UnownedTaskExecutor) -> ()
 
 @_unavailableInEmbedded
-@available(SwiftStdlib 6.0, *)
+@available(StdlibDeploymentTarget 6.0, *)
 @_silgen_name("swift_job_run_on_serial_and_task_executor")
 @usableFromInline
 internal func _swiftJobRunOnTaskExecutor(_ job: UnownedJob,
@@ -63,14 +63,14 @@ public struct UnownedJob: Sendable {
   private var context: Builtin.Job
 
   @usableFromInline
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   internal init(context: Builtin.Job) {
     self.context = context
   }
 
   #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
   /// Create an `UnownedJob` whose lifetime must be managed carefully until it is run exactly once.
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   public init(_ job: __owned Job) { // must remain '__owned' in order to not break ABI
     self.context = job.context
   }
@@ -78,27 +78,25 @@ public struct UnownedJob: Sendable {
 
   #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
   /// Create an `UnownedJob` whose lifetime must be managed carefully until it is run exactly once.
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   public init(_ job: __owned ExecutorJob) { // must remain '__owned' in order to not break ABI
     self.context = job.context
   }
   #endif // !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
 
   /// The priority of this job.
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   public var priority: JobPriority {
     let raw: UInt8
-    if #available(SwiftStdlib 6.2, *) {
+    if #available(StdlibDeploymentTarget 6.2, *) {
       raw = _jobGetPriority(context)
     } else {
-      // Since we're building the new version of the stdlib, we should
-      // never get here.
-      Builtin.unreachable()
+      fatalError("we shouldn't get here; if we have, availability is broken")
     }
     return JobPriority(rawValue: raw)
   }
 
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   internal var _context: Builtin.Job {
     context
   }
@@ -145,7 +143,7 @@ public struct UnownedJob: Sendable {
   ///
   /// - SeeAlso: ``runSynchronously(isolatedTo:taskExecutor:)``
   @_unavailableInEmbedded
-  @available(SwiftStdlib 6.0, *)
+  @available(StdlibDeploymentTarget 6.0, *)
   @_alwaysEmitIntoClient
   @inlinable
   public func runSynchronously(on executor: UnownedTaskExecutor) {
@@ -173,7 +171,7 @@ public struct UnownedJob: Sendable {
   ///
   /// - SeeAlso: ``runSynchronously(on:)``
   @_unavailableInEmbedded
-  @available(SwiftStdlib 6.0, *)
+  @available(StdlibDeploymentTarget 6.0, *)
   @_alwaysEmitIntoClient
   @inlinable
   public func runSynchronously(isolatedTo serialExecutor: UnownedSerialExecutor,
@@ -208,7 +206,7 @@ extension UnownedJob: CustomStringConvertible {
 ///
 /// Unless you're implementing a scheduler,
 /// you don't generally interact with jobs directly.
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 @available(*, deprecated, renamed: "ExecutorJob")
 @frozen
 public struct Job: Sendable, ~Copyable {
@@ -229,12 +227,10 @@ public struct Job: Sendable, ~Copyable {
 
   public var priority: JobPriority {
     let raw: UInt8
-    if #available(SwiftStdlib 6.2, *) {
+    if #available(StdlibDeploymentTarget 6.2, *) {
       raw = _jobGetPriority(self.context)
     } else {
-      // We are building the new version of the code, so we should never
-      // get here.
-      Builtin.unreachable()
+      fatalError("we shouldn't get here; if we have, availability is broken")
     }
     return JobPriority(rawValue: raw)
   }
@@ -284,7 +280,7 @@ extension Job {
 ///
 /// Unless you're implementing a scheduler,
 /// you don't generally interact with jobs directly.
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 @frozen
 public struct ExecutorJob: Sendable, ~Copyable {
   internal var context: Builtin.Job
@@ -302,27 +298,36 @@ public struct ExecutorJob: Sendable, ~Copyable {
     self.context = job.context
   }
 
-  public var priority: JobPriority {
-    let raw: UInt8
-    if #available(SwiftStdlib 6.2, *) {
-      raw = _jobGetPriority(self.context)
-    } else {
-      // We are building the new version of the code, so we should never
-      // get here.
-      Builtin.unreachable()
+  internal(set) public var priority: JobPriority {
+    get {
+      let raw: UInt8
+      if #available(StdlibDeploymentTarget 6.2, *) {
+        raw = _jobGetPriority(self.context)
+      } else {
+        fatalError("we shouldn't get here; if we have, availability is broken")
+      }
+      return JobPriority(rawValue: raw)
+    }
+    set {
+      if #available(StdlibDeploymentTarget 6.2, *) {
+        _jobSetPriority(self.context, newValue.rawValue)
+      } else {
+        fatalError("we shouldn't get here; if we have, availability is broken")
+      }
     }
-    return JobPriority(rawValue: raw)
   }
 
   /// Execute a closure, passing it the bounds of the executor private data
-  /// for the job.
+  /// for the job.  The executor is responsible for ensuring that any resources
+  /// referenced from the private data area are cleared up prior to running the
+  /// job.
   ///
   /// Parameters:
   ///
   /// - body: The closure to execute.
   ///
   /// Returns the result of executing the closure.
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public func withUnsafeExecutorPrivateData<R, E>(body: (UnsafeMutableRawBufferPointer) throws(E) -> R) throws(E) -> R {
     let base = unsafe _jobGetExecutorPrivateData(self.context)
     let size = unsafe 2 * MemoryLayout<OpaquePointer>.stride
@@ -331,7 +336,7 @@ public struct ExecutorJob: Sendable, ~Copyable {
   }
 
   /// Kinds of schedulable jobs
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   @frozen
   public struct Kind: Sendable, RawRepresentable {
     public typealias RawValue = UInt8
@@ -352,7 +357,7 @@ public struct ExecutorJob: Sendable, ~Copyable {
   }
 
   /// What kind of job this is.
-  @available(SwiftStdlib 6.2, *)
+  @available(StdlibDeploymentTarget 6.2, *)
   public var kind: Kind {
     return Kind(rawValue: _jobGetKind(self.context))!
   }
@@ -373,7 +378,7 @@ public struct ExecutorJob: Sendable, ~Copyable {
   }
 }
 
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 extension ExecutorJob {
 
   /// Run this job on the passed in executor.
@@ -415,7 +420,7 @@ extension ExecutorJob {
   ///
   /// - SeeAlso: ``runSynchronously(isolatedTo:taskExecutor:)``
   @_unavailableInEmbedded
-  @available(SwiftStdlib 6.0, *)
+  @available(StdlibDeploymentTarget 6.0, *)
   @_alwaysEmitIntoClient
   @inlinable
   __consuming public func runSynchronously(on executor: UnownedTaskExecutor) {
@@ -438,7 +443,7 @@ extension ExecutorJob {
   ///
   /// - SeeAlso: ``runSynchronously(on:)``
   @_unavailableInEmbedded
-  @available(SwiftStdlib 6.0, *)
+  @available(StdlibDeploymentTarget 6.0, *)
   @_alwaysEmitIntoClient
   @inlinable
   __consuming public func runSynchronously(isolatedTo serialExecutor: UnownedSerialExecutor,
@@ -447,8 +452,51 @@ extension ExecutorJob {
   }
 }
 
+// Helper to create a trampoline job to execute a job on a specified
+// executor.
+@available(StdlibDeploymentTarget 6.2, *)
+extension ExecutorJob {
+
+  /// Create a trampoline to enqueue the specified job on the specified
+  /// executor.
+  ///
+  /// This is useful in conjunction with the `Clock.run()` API, which
+  /// runs a job on an unspecified executor.
+  ///
+  /// Parameters:
+  ///
+  /// - to executor:   The `Executor` on which it should be enqueued.
+  ///
+  /// Returns:
+  ///
+  /// A new ExecutorJob that will enqueue the specified job on the specified
+  /// executor.
+  @available(StdlibDeploymentTarget 6.2, *)
+  public func createTrampoline(to executor: some Executor) -> ExecutorJob {
+    let flags = taskCreateFlags(
+      priority: TaskPriority(priority),
+      isChildTask: false,
+      copyTaskLocals: false,
+      inheritContext: false,
+      enqueueJob: false,
+      addPendingGroupTaskUnconditionally: false,
+      isDiscardingTask: false,
+      isSynchronousStart: false
+    )
+
+    let unownedJob = UnownedJob(context: self.context)
+    let (trampolineTask, _) = Builtin.createAsyncTask(flags) {
+      executor.enqueue(unownedJob)
+    }
+    let trampoline = Builtin.convertTaskToJob(trampolineTask)
+
+    return ExecutorJob(context: trampoline)
+  }
+
+}
+
 // Stack-disciplined job-local allocator support
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 extension ExecutorJob {
 
   /// Obtain a stack-disciplined job-local allocator.
@@ -465,9 +513,8 @@ extension ExecutorJob {
   /// A job-local stack-disciplined allocator.
   ///
   /// This can be used to allocate additional data required by an
-  /// executor implementation; memory allocated in this manner will
-  /// be released automatically when the job is disposed of by the
-  /// runtime.
+  /// executor implementation; memory allocated in this manner must
+  /// be released by the executor before the job is executed.
   ///
   /// N.B. Because this allocator is stack disciplined, explicitly
   /// deallocating memory out-of-order will cause your program to abort.
@@ -495,23 +542,20 @@ extension ExecutorJob {
       return unsafe UnsafeMutableBufferPointer<T>(start: typedBase, count: capacity)
     }
 
-    /// Deallocate previously allocated memory.  Note that the task
-    /// allocator is stack disciplined, so if you deallocate a block of
-    /// memory, all memory allocated after that block is also deallocated.
+    /// Deallocate previously allocated memory.  You must do this in
+    /// reverse order of allocations, prior to running the job.
     public func deallocate(_ buffer: UnsafeMutableRawBufferPointer) {
       unsafe _jobDeallocate(context, buffer.baseAddress!)
     }
 
-    /// Deallocate previously allocated memory.  Note that the task
-    /// allocator is stack disciplined, so if you deallocate a block of
-    /// memory, all memory allocated after that block is also deallocated.
+    /// Deallocate previously allocated memory.  You must do this in
+    /// reverse order of allocations, prior to running the job.
     public func deallocate<T>(_ pointer: UnsafeMutablePointer<T>) {
       unsafe _jobDeallocate(context, UnsafeMutableRawPointer(pointer))
     }
 
-    /// Deallocate previously allocated memory.  Note that the task
-    /// allocator is stack disciplined, so if you deallocate a block of
-    /// memory, all memory allocated after that block is also deallocated.
+    /// Deallocate previously allocated memory.    You must do this in
+    /// reverse order of allocations, prior to running the job.
     public func deallocate<T>(_ buffer: UnsafeMutableBufferPointer<T>) {
       unsafe _jobDeallocate(context, UnsafeMutableRawPointer(buffer.baseAddress!))
     }
@@ -539,21 +583,31 @@ extension ExecutorJob {
 /// however, since not all jobs are tasks, represented as separate type.
 ///
 /// Conversions between the two priorities are available as initializers on the respective types.
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 @frozen
 public struct JobPriority: Sendable {
   public typealias RawValue = UInt8
 
   /// The raw priority value.
   public var rawValue: RawValue
+
+  /// Construct from a raw value
+  public init(rawValue: RawValue) {
+    self.rawValue = rawValue
+  }
+
+  /// Construct from a TaskPriority
+  public init(_ p: TaskPriority) {
+    self.rawValue = p.rawValue
+  }
 }
 
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 extension TaskPriority {
   /// Convert this ``UnownedJob/Priority`` to a ``TaskPriority``.
   ///
   /// Most values are directly interchangeable, but this initializer reserves the right to fail for certain values.
-  @available(SwiftStdlib 5.9, *)
+  @available(StdlibDeploymentTarget 5.9, *)
   public init?(_ p: JobPriority) {
     guard p.rawValue != 0 else {
       // 0 is "undefined"
@@ -563,7 +617,7 @@ extension TaskPriority {
   }
 }
 
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 extension JobPriority: Equatable {
   public static func == (lhs: JobPriority, rhs: JobPriority) -> Bool {
     lhs.rawValue == rhs.rawValue
@@ -574,7 +628,7 @@ extension JobPriority: Equatable {
   }
 }
 
-@available(SwiftStdlib 5.9, *)
+@available(StdlibDeploymentTarget 5.9, *)
 extension JobPriority: Comparable {
   public static func < (lhs: JobPriority, rhs: JobPriority) -> Bool {
     lhs.rawValue < rhs.rawValue
@@ -915,3 +969,19 @@ public func _unsafeInheritExecutor_withUnsafeThrowingContinuation<T>(
 public func _abiEnableAwaitContinuation() {
   fatalError("never use this function")
 }
+
+#if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+@available(StdlibDeploymentTarget 6.2, *)
+@_silgen_name("_swift_createJobForTestingOnly")
+public func _swift_createJobForTestingOnly(
+  priority: TaskPriority = TaskPriority.medium,
+  _ body: @escaping () -> ()
+) -> ExecutorJob {
+  let flags: Int = Int(priority.rawValue)
+  let (task, _) = Builtin.createAsyncTask(flags, body)
+  var job = ExecutorJob(unsafe unsafeBitCast(Builtin.convertTaskToJob(task),
+      to: UnownedJob.self))
+  job.priority = JobPriority(priority)
+  return job
+}
+#endif
diff --git a/stdlib/public/Concurrency/PlatformExecutorCooperative.swift b/stdlib/public/Concurrency/PlatformExecutorCooperative.swift
index 5c17e1d2ba084..e9288bfc7cdd7 100644
--- a/stdlib/public/Concurrency/PlatformExecutorCooperative.swift
+++ b/stdlib/public/Concurrency/PlatformExecutorCooperative.swift
@@ -13,7 +13,7 @@
 import Swift
 
 // This platform uses a single, global, CooperativeExecutor
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 public struct PlatformExecutorFactory: ExecutorFactory {
   static let executor = CooperativeExecutor()
   public static var mainExecutor: any MainExecutor { executor }
diff --git a/stdlib/public/Concurrency/PlatformExecutorDarwin.swift b/stdlib/public/Concurrency/PlatformExecutorDarwin.swift
index 90017beb45106..71cf93d92f879 100644
--- a/stdlib/public/Concurrency/PlatformExecutorDarwin.swift
+++ b/stdlib/public/Concurrency/PlatformExecutorDarwin.swift
@@ -14,7 +14,7 @@
 
 import Swift
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 public struct PlatformExecutorFactory: ExecutorFactory {
   public static var mainExecutor: any MainExecutor {
     if CoreFoundation.isPresent {
diff --git a/stdlib/public/Concurrency/PlatformExecutorFreeBSD.swift b/stdlib/public/Concurrency/PlatformExecutorFreeBSD.swift
new file mode 100644
index 0000000000000..b7a4deb25356c
--- /dev/null
+++ b/stdlib/public/Concurrency/PlatformExecutorFreeBSD.swift
@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2020 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#if !$Embedded && os(FreeBSD)
+
+import Swift
+
+// The default executors for now are Dispatch-based
+@available(SwiftStdlib 6.2, *)
+public struct PlatformExecutorFactory: ExecutorFactory {
+  public static let mainExecutor: any MainExecutor = DispatchMainExecutor()
+  public static let defaultExecutor: any TaskExecutor
+    = DispatchGlobalTaskExecutor()
+}
+
+#endif // os(FreeBSD)
diff --git a/stdlib/public/Concurrency/PlatformExecutorLinux.swift b/stdlib/public/Concurrency/PlatformExecutorLinux.swift
index a14c492c8ab59..19d245a1a7e6e 100644
--- a/stdlib/public/Concurrency/PlatformExecutorLinux.swift
+++ b/stdlib/public/Concurrency/PlatformExecutorLinux.swift
@@ -15,7 +15,7 @@
 import Swift
 
 // The default executors for now are Dispatch-based
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 public struct PlatformExecutorFactory: ExecutorFactory {
   public static let mainExecutor: any MainExecutor = DispatchMainExecutor()
   public static let defaultExecutor: any TaskExecutor
diff --git a/stdlib/public/Concurrency/PlatformExecutorNone.swift b/stdlib/public/Concurrency/PlatformExecutorNone.swift
index a524f07005d85..c052893f5413a 100644
--- a/stdlib/public/Concurrency/PlatformExecutorNone.swift
+++ b/stdlib/public/Concurrency/PlatformExecutorNone.swift
@@ -12,8 +12,8 @@
 
 import Swift
 
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 public struct PlatformExecutorFactory: ExecutorFactory {
-  public static let mainExecutor: any MainExecutor = DummyMainExecutor()
-  public static let defaultExecutor: any TaskExecutor = DummyTaskExecutor()
+  public static let mainExecutor: any MainExecutor = UnimplementedMainExecutor()
+  public static let defaultExecutor: any TaskExecutor = UnimplementedTaskExecutor()
 }
diff --git a/stdlib/public/Concurrency/PlatformExecutorOpenBSD.swift b/stdlib/public/Concurrency/PlatformExecutorOpenBSD.swift
new file mode 100644
index 0000000000000..4bd2db9d5ebdc
--- /dev/null
+++ b/stdlib/public/Concurrency/PlatformExecutorOpenBSD.swift
@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2020 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#if !$Embedded && os(OpenBSD)
+
+import Swift
+
+// The default executors for now are Dispatch-based
+@available(SwiftStdlib 6.2, *)
+public struct PlatformExecutorFactory: ExecutorFactory {
+  public static let mainExecutor: any MainExecutor = DispatchMainExecutor()
+  public static let defaultExecutor: any TaskExecutor
+    = DispatchGlobalTaskExecutor()
+}
+
+#endif
diff --git a/stdlib/public/Concurrency/PlatformExecutorWindows.swift b/stdlib/public/Concurrency/PlatformExecutorWindows.swift
index e64665a94da37..08ec70519931c 100644
--- a/stdlib/public/Concurrency/PlatformExecutorWindows.swift
+++ b/stdlib/public/Concurrency/PlatformExecutorWindows.swift
@@ -15,7 +15,7 @@
 import Swift
 
 // The default executors for now are Dispatch-based
-@available(SwiftStdlib 6.2, *)
+@available(StdlibDeploymentTarget 6.2, *)
 public struct PlatformExecutorFactory: ExecutorFactory {
   public static let mainExecutor: any MainExecutor = DispatchMainExecutor()
   public static let defaultExecutor: any TaskExecutor =
diff --git a/stdlib/public/Concurrency/PriorityQueue.swift b/stdlib/public/Concurrency/PriorityQueue.swift
index 744c9c4c257a2..b3839167ae823 100644
--- a/stdlib/public/Concurrency/PriorityQueue.swift
+++ b/stdlib/public/Concurrency/PriorityQueue.swift
@@ -40,6 +40,15 @@ struct PriorityQueue<T> {
     self.compare = compare
   }
 
+  /// Take the queue.
+  ///
+  /// This returns a copy of the queue, and empties the original.
+  mutating func take() -> PriorityQueue<T> {
+    var q = PriorityQueue(compare: self.compare)
+    swap(&self, &q)
+    return q
+  }
+
   /// Push an item onto the queue.
   ///
   /// Parameters:
@@ -51,6 +60,11 @@ struct PriorityQueue<T> {
     upHeap(ndx: storage.count - 1)
   }
 
+  /// Return `true` if the queue is empty
+  var isEmpty: Bool {
+    return storage.isEmpty
+  }
+
   /// The highest priority item from the queue, or `nil` if none.
   var top: T? {
     if storage.isEmpty {
diff --git a/stdlib/public/Concurrency/Setup.cpp b/stdlib/public/Concurrency/Setup.cpp
deleted file mode 100644
index 628a6ef0240f2..0000000000000
--- a/stdlib/public/Concurrency/Setup.cpp
+++ /dev/null
@@ -1,56 +0,0 @@
-//===--- Setup.cpp - Load-time setup code ---------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-#include "swift/Runtime/Metadata.h"
-
-// Helper macros for figuring out the mangled name of a context descriptor.
-#define DESCRIPTOR_MANGLING_SUFFIX_Structure Mn
-#define DESCRIPTOR_MANGLING_SUFFIX_Class Mn
-#define DESCRIPTOR_MANGLING_SUFFIX_Enum Mn
-#define DESCRIPTOR_MANGLING_SUFFIX_Protocol Mp
-
-#define DESCRIPTOR_MANGLING_SUFFIX_(X) X
-#define DESCRIPTOR_MANGLING_SUFFIX(KIND)                                       \
-  DESCRIPTOR_MANGLING_SUFFIX_(DESCRIPTOR_MANGLING_SUFFIX_##KIND)
-
-#define DESCRIPTOR_MANGLING_(CHAR, SUFFIX) $sSc##CHAR##SUFFIX
-#define DESCRIPTOR_MANGLING(CHAR, SUFFIX) DESCRIPTOR_MANGLING_(CHAR, SUFFIX)
-
-// Declare context descriptors for all of the concurrency descriptors with
-// standard manglings.
-#define STANDARD_TYPE(KIND, MANGLING, TYPENAME)
-#define STANDARD_TYPE_CONCURRENCY(KIND, MANGLING, TYPENAME)                    \
-  extern "C" const swift::ContextDescriptor DESCRIPTOR_MANGLING(               \
-      MANGLING, DESCRIPTOR_MANGLING_SUFFIX(KIND));
-#include "swift/Demangling/StandardTypesMangling.def"
-
-// Defined in Swift, redeclared here so we can register it with the runtime.
-extern "C" SWIFT_CC(swift)
-bool _swift_task_isCurrentGlobalActor(
-    const swift::Metadata *, const swift::WitnessTable *);
-
-// Register our type descriptors with standard manglings when the concurrency
-// runtime is loaded. This allows the runtime to quickly resolve those standard
-// manglings.
-SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_BEGIN
-__attribute__((constructor)) static void setupStandardConcurrencyDescriptors() {
-  static const swift::ConcurrencyStandardTypeDescriptors descriptors = {
-#define STANDARD_TYPE(KIND, MANGLING, TYPENAME)
-#define STANDARD_TYPE_CONCURRENCY(KIND, MANGLING, TYPENAME)                    \
-  &DESCRIPTOR_MANGLING(MANGLING, DESCRIPTOR_MANGLING_SUFFIX(KIND)),
-#include "swift/Demangling/StandardTypesMangling.def"
-  };
-  _swift_registerConcurrencyRuntime(
-      &descriptors,
-      &_swift_task_isCurrentGlobalActor);
-}
-SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_END
diff --git a/stdlib/public/Concurrency/SourceCompatibilityShims.swift b/stdlib/public/Concurrency/SourceCompatibilityShims.swift
index 75242f0421b1f..46364319adf99 100644
--- a/stdlib/public/Concurrency/SourceCompatibilityShims.swift
+++ b/stdlib/public/Concurrency/SourceCompatibilityShims.swift
@@ -87,175 +87,6 @@ extension Task where Success == Never, Failure == Never {
   }
 }
 
-@available(SwiftStdlib 5.1, *)
-extension Task where Failure == Error {
-  #if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-  public static func runDetached(
-    priority: TaskPriority? = nil,
-    operation: __owned @Sendable @escaping () async throws -> Success
-  ) -> Task<Success, Failure> {
-    fatalError("Unavailable in task-to-thread concurrency model")
-  }
-  #else
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, deprecated, message: "`Task.runDetached` was replaced by `Task.detached` and will be removed shortly.")
-  public static func runDetached(
-    priority: TaskPriority? = nil,
-    operation: __owned @Sendable @escaping () async throws -> Success
-  ) -> Task<Success, Failure> {
-    detached(priority: priority, operation: operation)
-  }
-  #endif
-}
-
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@discardableResult
-@available(SwiftStdlib 5.1, *)
-@available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-@_alwaysEmitIntoClient
-public func detach<T>(
-  priority: TaskPriority? = nil,
-  operation: __owned @Sendable @escaping () async -> T
-) -> Task<T, Never> {
-  fatalError("Unavailable in task-to-thread concurrency model")
-}
-#else
-@discardableResult
-@available(SwiftStdlib 5.1, *)
-@available(*, deprecated, message: "`detach` was replaced by `Task.detached` and will be removed shortly.")
-@_alwaysEmitIntoClient
-public func detach<T>(
-  priority: TaskPriority? = nil,
-  operation: __owned @Sendable @escaping () async -> T
-) -> Task<T, Never> {
-  Task.detached(priority: priority, operation: operation)
-}
-#endif
-
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@discardableResult
-@available(SwiftStdlib 5.1, *)
-@available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-@_alwaysEmitIntoClient
-public func detach<T>(
-  priority: TaskPriority? = nil,
-  operation: __owned @Sendable @escaping () async throws -> T
-) -> Task<T, Error> {
-  fatalError("Unavailable in task-to-thread concurrency model")
-}
-#else
-@discardableResult
-@available(SwiftStdlib 5.1, *)
-@available(*, deprecated, message: "`detach` was replaced by `Task.detached` and will be removed shortly.")
-@_alwaysEmitIntoClient
-public func detach<T>(
-  priority: TaskPriority? = nil,
-  operation: __owned @Sendable @escaping () async throws -> T
-) -> Task<T, Error> {
-  Task.detached(priority: priority, operation: operation)
-}
-#endif
-
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@discardableResult
-@available(SwiftStdlib 5.1, *)
-@available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-@_alwaysEmitIntoClient
-public func asyncDetached<T>(
-  priority: TaskPriority? = nil,
-  @_implicitSelfCapture operation: __owned @Sendable @escaping () async -> T
-) -> Task<T, Never> {
-  fatalError("Unavailable in task-to-thread concurrency model")
-}
-#else
-@discardableResult
-@available(SwiftStdlib 5.1, *)
-@available(*, deprecated, message: "`asyncDetached` was replaced by `Task.detached` and will be removed shortly.")
-@_alwaysEmitIntoClient
-public func asyncDetached<T>(
-  priority: TaskPriority? = nil,
-  @_implicitSelfCapture operation: __owned @Sendable @escaping () async -> T
-) -> Task<T, Never> {
-  return Task.detached(priority: priority, operation: operation)
-}
-#endif
-
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@discardableResult
-@available(SwiftStdlib 5.1, *)
-@available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-@_alwaysEmitIntoClient
-public func asyncDetached<T>(
-  priority: TaskPriority? = nil,
-  @_implicitSelfCapture operation: __owned @Sendable @escaping () async throws -> T
-) -> Task<T, Error> {
-  fatalError("Unavailable in task-to-thread concurrency model")
-}
-#else
-@discardableResult
-@available(SwiftStdlib 5.1, *)
-@available(*, deprecated, message: "`asyncDetached` was replaced by `Task.detached` and will be removed shortly.")
-@_alwaysEmitIntoClient
-public func asyncDetached<T>(
-  priority: TaskPriority? = nil,
-  @_implicitSelfCapture operation: __owned @Sendable @escaping () async throws -> T
-) -> Task<T, Error> {
-  return Task.detached(priority: priority, operation: operation)
-}
-#endif
-
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@available(SwiftStdlib 5.1, *)
-@available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-@discardableResult
-@_alwaysEmitIntoClient
-public func async<T>(
-  priority: TaskPriority? = nil,
-  @_inheritActorContext @_implicitSelfCapture operation: __owned @Sendable @escaping () async -> T
-) -> Task<T, Never> {
-  fatalError("Unavailable in task-to-thread concurrency model")
-}
-#else
-@available(SwiftStdlib 5.1, *)
-@available(*, deprecated, message: "`async` was replaced by `Task.init` and will be removed shortly.")
-@discardableResult
-@_alwaysEmitIntoClient
-public func async<T>(
-  priority: TaskPriority? = nil,
-  @_inheritActorContext @_implicitSelfCapture operation: __owned @Sendable @escaping () async -> T
-) -> Task<T, Never> {
-  .init(priority: priority, operation: operation)
-}
-#endif
-
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@available(SwiftStdlib 5.1, *)
-@available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-@discardableResult
-@_alwaysEmitIntoClient
-public func async<T>(
-  priority: TaskPriority? = nil,
-  @_inheritActorContext @_implicitSelfCapture operation: __owned @Sendable @escaping () async throws -> T
-) -> Task<T, Error> {
-  fatalError("Unavailable in task-to-thread concurrency model")
-}
-#else
-@available(SwiftStdlib 5.1, *)
-@available(*, deprecated, message: "`async` was replaced by `Task.init` and will be removed shortly.")
-@discardableResult
-@_alwaysEmitIntoClient
-public func async<T>(
-  priority: TaskPriority? = nil,
-  @_inheritActorContext @_implicitSelfCapture operation: __owned @Sendable @escaping () async throws -> T
-) -> Task<T, Error> {
-  .init(priority: priority, operation: operation)
-}
-#endif
-
 @available(SwiftStdlib 5.1, *)
 extension Task where Success == Never, Failure == Never {
   @available(*, deprecated, message: "`Task.Group` was replaced by `ThrowingTaskGroup` and `TaskGroup` and will be removed shortly.")
diff --git a/stdlib/public/Concurrency/SuspendingClock.swift b/stdlib/public/Concurrency/SuspendingClock.swift
index cec63ed99f55e..6696ae7767d41 100644
--- a/stdlib/public/Concurrency/SuspendingClock.swift
+++ b/stdlib/public/Concurrency/SuspendingClock.swift
@@ -20,7 +20,7 @@ import Swift
 /// only comparable on the same machine in the same booted session.
 ///
 /// This clock is suitable for high resolution measurements of execution.
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_unavailableInEmbedded
 public struct SuspendingClock: Sendable {
   public struct Instant: Sendable {
@@ -35,12 +35,12 @@ public struct SuspendingClock: Sendable {
 }
 
 #if !$Embedded
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension SuspendingClock.Instant: Codable {
 }
 #endif
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_unavailableInEmbedded
 extension Clock where Self == SuspendingClock {
   /// A clock that measures time that always increments but stops incrementing
@@ -48,21 +48,21 @@ extension Clock where Self == SuspendingClock {
   ///
   ///       try await Task.sleep(until: .now + .seconds(3), clock: .suspending)
   ///
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static var suspending: SuspendingClock { return SuspendingClock() }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_unavailableInEmbedded
 extension SuspendingClock: Clock {
   /// The current instant accounting for machine suspension.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public var now: SuspendingClock.Instant {
     SuspendingClock.now
   }
 
   /// The current instant accounting for machine suspension.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static var now: SuspendingClock.Instant {
     var seconds = Int64(0)
     var nanoseconds = Int64(0)
@@ -76,7 +76,7 @@ extension SuspendingClock: Clock {
   }
 
   /// The minimum non-zero resolution between any two calls to `now`.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public var minimumResolution: Swift.Duration {
     var seconds = Int64(0)
     var nanoseconds = Int64(0)
@@ -87,12 +87,6 @@ extension SuspendingClock: Clock {
     return Duration(_seconds: seconds, nanoseconds: nanoseconds)
   }
 
-  /// The suspending clock is monotonic
-  @available(SwiftStdlib 6.2, *)
-  public var traits: ClockTraits {
-    return [.monotonic]
-  }
-
 #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
   /// Suspend task execution until a given deadline within a tolerance.
   /// If no tolerance is specified then the system may adjust the deadline
@@ -103,21 +97,20 @@ extension SuspendingClock: Clock {
   /// `CancellationError`.
   ///
   /// This function doesn't block the underlying thread.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public func sleep(
     until deadline: Instant, tolerance: Swift.Duration? = nil
   ) async throws {
-    if #available(SwiftStdlib 6.2, *) {
+    if #available(StdlibDeploymentTarget 6.2, *) {
       try await Task._sleep(until: deadline,
                             tolerance: tolerance,
                             clock: self)
     } else {
-      // Should never see this
-      Builtin.unreachable()
+      fatalError("we shouldn't get here; if we have, availability is broken")
     }
   }
 #else
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
   public func sleep(
     until deadline: Instant, tolerance: Swift.Duration? = nil
@@ -127,73 +120,105 @@ extension SuspendingClock: Clock {
 #endif
 }
 
+@available(StdlibDeploymentTarget 5.7, *)
+@_unavailableInEmbedded
+extension SuspendingClock {
+  @available(SwiftStdlib 5.7, *)
+  @_alwaysEmitIntoClient
+  public var systemEpoch: Instant {
+    unsafe unsafeBitCast(Duration.seconds(0), to: Instant.self)
+  }
+}
+
 @available(SwiftStdlib 5.7, *)
 @_unavailableInEmbedded
 extension SuspendingClock.Instant: InstantProtocol {
-  @available(SwiftStdlib 5.7, *)
   public static var now: SuspendingClock.Instant { SuspendingClock().now }
 
-  @available(SwiftStdlib 5.7, *)
   public func advanced(by duration: Swift.Duration) -> SuspendingClock.Instant {
     SuspendingClock.Instant(_value: _value + duration)
   }
 
-  @available(SwiftStdlib 5.7, *)
   public func duration(to other: SuspendingClock.Instant) -> Swift.Duration {
     other._value - _value
   }
 
-  @available(SwiftStdlib 5.7, *)
   public func hash(into hasher: inout Hasher) {
     hasher.combine(_value)
   }
 
-  @available(SwiftStdlib 5.7, *)
   public static func == (
     _ lhs: SuspendingClock.Instant, _ rhs: SuspendingClock.Instant
   ) -> Bool {
     return lhs._value == rhs._value
   }
 
-  @available(SwiftStdlib 5.7, *)
   public static func < (
     _ lhs: SuspendingClock.Instant, _ rhs: SuspendingClock.Instant
   ) -> Bool {
     return lhs._value < rhs._value
   }
 
-  @available(SwiftStdlib 5.7, *)
   public static func + (
     _ lhs: SuspendingClock.Instant, _ rhs: Swift.Duration
   ) -> SuspendingClock.Instant {
     lhs.advanced(by: rhs)
   }
 
-  @available(SwiftStdlib 5.7, *)
   public static func += (
     _ lhs: inout SuspendingClock.Instant, _ rhs: Swift.Duration
   ) {
     lhs = lhs.advanced(by: rhs)
   }
 
-  @available(SwiftStdlib 5.7, *)
   public static func - (
     _ lhs: SuspendingClock.Instant, _ rhs: Swift.Duration
   ) -> SuspendingClock.Instant {
     lhs.advanced(by: .zero - rhs)
   }
 
-  @available(SwiftStdlib 5.7, *)
   public static func -= (
     _ lhs: inout SuspendingClock.Instant, _ rhs: Swift.Duration
   ) {
     lhs = lhs.advanced(by: .zero - rhs)
   }
 
-  @available(SwiftStdlib 5.7, *)
   public static func - (
     _ lhs: SuspendingClock.Instant, _ rhs: SuspendingClock.Instant
   ) -> Swift.Duration {
     rhs.duration(to: lhs)
   }
 }
+
+#if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+@available(StdlibDeploymentTarget 6.2, *)
+extension SuspendingClock {
+
+  public func run(_ job: consuming ExecutorJob,
+                  at instant: Instant,
+                  tolerance: Duration?) {
+    guard let executor = Task<Never,Never>.currentSchedulingExecutor else {
+      fatalError("no scheduling executor is available")
+    }
+
+    executor.enqueue(job, at: instant,
+                     tolerance: tolerance,
+                     clock: self)
+  }
+
+  public func enqueue(_ job: consuming ExecutorJob,
+                      on executor: some Executor,
+                      at instant: Instant,
+                      tolerance: Duration?) {
+    if let schedulingExecutor = executor.asSchedulingExecutor {
+      schedulingExecutor.enqueue(job, at: instant,
+                                 tolerance: tolerance,
+                                 clock: self)
+    } else {
+      let trampoline = job.createTrampoline(to: executor)
+      run(trampoline, at: instant, tolerance: tolerance)
+    }
+  }
+
+}
+#endif
diff --git a/stdlib/public/Concurrency/Task+PriorityEscalation.swift b/stdlib/public/Concurrency/Task+PriorityEscalation.swift
index 515e25088a36e..768fc4eae61ce 100644
--- a/stdlib/public/Concurrency/Task+PriorityEscalation.swift
+++ b/stdlib/public/Concurrency/Task+PriorityEscalation.swift
@@ -94,7 +94,7 @@ extension UnsafeCurrentTask {
 /// The handler will only trigger if a priority escalation occurs while the
 /// operation is in progress.
 ///
-/// If multiple task escalation handlers are nester they will all be triggered.
+/// If multiple task escalation handlers are nested they will all be triggered.
 ///
 /// Task escalation propagates through structured concurrency child-tasks.
 ///
@@ -129,4 +129,4 @@ func __withTaskPriorityEscalationHandler0<T, E>(
   defer { unsafe _taskRemovePriorityEscalationHandler(record: record) }
 
   return try await operation()
-}
\ No newline at end of file
+}
diff --git a/stdlib/public/Concurrency/Task+TaskExecutor.swift b/stdlib/public/Concurrency/Task+TaskExecutor.swift
index 611fe9265630f..ca04d74c63afe 100644
--- a/stdlib/public/Concurrency/Task+TaskExecutor.swift
+++ b/stdlib/public/Concurrency/Task+TaskExecutor.swift
@@ -187,263 +187,6 @@ public func _unsafeInheritExecutor_withTaskExecutorPreference<T: Sendable>(
   return try await operation()
 }
 
-/// Task with specified executor -----------------------------------------------
-
-@available(SwiftStdlib 6.0, *)
-@_unavailableInEmbedded
-extension Task where Failure == Never {
-  /// Runs the given nonthrowing operation asynchronously
-  /// as part of a new top-level task on behalf of the current actor.
-  ///
-  /// This overload allows specifying a preferred ``TaskExecutor`` on which
-  /// the `operation`, as well as all child tasks created from this task will be
-  /// executing whenever possible. Refer to ``TaskExecutor`` for a detailed discussion
-  /// of the effect of task executors on execution semantics of asynchronous code.
-  ///
-  /// Use this function when creating asynchronous work
-  /// that operates on behalf of the synchronous function that calls it.
-  /// Like `Task.detached(priority:operation:)`,
-  /// this function creates a separate, top-level task.
-  /// Unlike `Task.detached(priority:operation:)`,
-  /// the task created by `Task.init(priority:operation:)`
-  /// inherits the priority and actor context of the caller,
-  /// so the operation is treated more like an asynchronous extension
-  /// to the synchronous operation.
-  ///
-  /// You need to keep a reference to the task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - taskExecutor: the preferred task executor for this task,
-  ///       and any child tasks created by it. Explicitly passing `nil` is
-  ///       interpreted as "no preference".
-  ///   - priority: The priority of the task.
-  ///     Pass `nil` to use the priority from `Task.currentPriority`.
-  ///   - operation: The operation to perform.
-  /// - SeeAlso: ``withTaskExecutorPreference(_:operation:)``
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public init(
-    executorPreference taskExecutor: consuming (any TaskExecutor)?,
-    priority: TaskPriority? = nil,
-    operation: sending @escaping () async -> Success
-  ) {
-    guard let taskExecutor else {
-      self = Self.init(priority: priority, operation: operation)
-      return
-    }
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: true,
-      inheritContext: true, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-#if $BuiltinCreateAsyncTaskOwnedTaskExecutor
-    let (task, _) = Builtin.createTask(
-      flags: flags,
-      initialTaskExecutorConsuming: taskExecutor,
-      operation: operation)
-#else
-    let executorBuiltin: Builtin.Executor =
-      taskExecutor.asUnownedTaskExecutor().executor
-    let (task, _) = Builtin.createAsyncTaskWithExecutor(
-      flags, executorBuiltin, operation)
-#endif
-    self._task = task
-  }
-}
-
-@available(SwiftStdlib 6.0, *)
-@_unavailableInEmbedded
-extension Task where Failure == Error {
-  /// Runs the given throwing operation asynchronously
-  /// as part of a new top-level task on behalf of the current actor.
-  ///
-  /// Use this function when creating asynchronous work
-  /// that operates on behalf of the synchronous function that calls it.
-  /// Like `Task.detached(priority:operation:)`,
-  /// this function creates a separate, top-level task.
-  /// Unlike `detach(priority:operation:)`,
-  /// the task created by `Task.init(priority:operation:)`
-  /// inherits the priority and actor context of the caller,
-  /// so the operation is treated more like an asynchronous extension
-  /// to the synchronous operation.
-  ///
-  /// You need to keep a reference to the task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - taskExecutor: the preferred task executor for this task,
-  ///       and any child tasks created by it. Explicitly passing `nil` is
-  ///       interpreted as "no preference".
-  ///   - priority: The priority of the task.
-  ///     Pass `nil` to use the priority from `Task.currentPriority`.
-  ///   - operation: The operation to perform.
-  /// - SeeAlso: ``withTaskExecutorPreference(_:operation:)``
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public init(
-    executorPreference taskExecutor: consuming (any TaskExecutor)?,
-    priority: TaskPriority? = nil,
-    operation: sending @escaping () async throws -> Success
-  ) {
-    guard let taskExecutor else {
-      self = Self.init(priority: priority, operation: operation)
-      return
-    }
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: true,
-      inheritContext: true, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-#if $BuiltinCreateAsyncTaskOwnedTaskExecutor
-    let (task, _) = Builtin.createTask(
-      flags: flags,
-      initialTaskExecutorConsuming: taskExecutor,
-      operation: operation)
-#else
-    let executorBuiltin: Builtin.Executor =
-      taskExecutor.asUnownedTaskExecutor().executor
-    let (task, _) = Builtin.createAsyncTaskWithExecutor(
-      flags, executorBuiltin, operation)
-#endif
-    self._task = task
-  }
-}
-
-// ==== Detached tasks ---------------------------------------------------------
-
-@available(SwiftStdlib 6.0, *)
-@_unavailableInEmbedded
-extension Task where Failure == Never {
-  /// Runs the given nonthrowing operation asynchronously
-  /// as part of a new top-level task.
-  ///
-  /// Don't use a detached task if it's possible
-  /// to model the operation using structured concurrency features like child tasks.
-  /// Child tasks inherit the parent task's priority and task-local storage,
-  /// and canceling a parent task automatically cancels all of its child tasks.
-  /// You need to handle these considerations manually with a detached task.
-  ///
-  /// You need to keep a reference to the detached task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - taskExecutor: the preferred task executor for this task,
-  ///       and any child tasks created by it. Explicitly passing `nil` is
-  ///       interpreted as "no preference".
-  ///   - priority: The priority of the task.
-  ///     Pass `nil` to use the priority from `Task.currentPriority`.
-  ///   - operation: The operation to perform.
-  /// - Returns: A reference to the newly created task.
-  /// - SeeAlso: ``withTaskExecutorPreference(_:operation:)``
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public static func detached(
-    executorPreference taskExecutor: (any TaskExecutor)?,
-    priority: TaskPriority? = nil,
-    operation: sending @escaping () async -> Success
-  ) -> Task<Success, Failure> {
-    guard let taskExecutor else {
-      return Self.detached(priority: priority, operation: operation)
-    }
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: false,
-      inheritContext: false, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-#if $BuiltinCreateAsyncTaskOwnedTaskExecutor
-    let (task, _) = Builtin.createTask(
-      flags: flags,
-      initialTaskExecutorConsuming: taskExecutor,
-      operation: operation)
-#else
-    let executorBuiltin: Builtin.Executor =
-      taskExecutor.asUnownedTaskExecutor().executor
-    let (task, _) = Builtin.createAsyncTaskWithExecutor(
-      flags, executorBuiltin, operation)
-#endif
-    return Task(task)
-  }
-}
-
-@available(SwiftStdlib 6.0, *)
-@_unavailableInEmbedded
-extension Task where Failure == Error {
-  /// Runs the given throwing operation asynchronously
-  /// as part of a new top-level task.
-  ///
-  /// If the operation throws an error, this method propagates that error.
-  ///
-  /// Don't use a detached task if it's possible
-  /// to model the operation using structured concurrency features like child tasks.
-  /// Child tasks inherit the parent task's priority and task-local storage,
-  /// and canceling a parent task automatically cancels all of its child tasks.
-  /// You need to handle these considerations manually with a detached task.
-  ///
-  /// You need to keep a reference to the detached task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - taskExecutor: the preferred task executor for this task,
-  ///       and any child tasks created by it. Explicitly passing `nil` is
-  ///       interpreted as "no preference".
-  ///   - priority: The priority of the task.
-  ///     Pass `nil` to use the priority from `Task.currentPriority`.
-  ///   - operation: The operation to perform.
-  /// - Returns: A reference to the newly created task.
-  /// - SeeAlso: ``withTaskExecutorPreference(_:operation:)``
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public static func detached(
-    executorPreference taskExecutor: (any TaskExecutor)?,
-    priority: TaskPriority? = nil,
-    operation: sending @escaping () async throws -> Success
-  ) -> Task<Success, Failure> {
-    guard let taskExecutor else {
-      return Self.detached(priority: priority, operation: operation)
-    }
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: false,
-      inheritContext: false, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-#if $BuiltinCreateAsyncTaskOwnedTaskExecutor
-    let (task, _) = Builtin.createTask(
-      flags: flags,
-      initialTaskExecutorConsuming: taskExecutor,
-      operation: operation)
-#else
-    let executorBuiltin: Builtin.Executor =
-      taskExecutor.asUnownedTaskExecutor().executor
-    let (task, _) = Builtin.createAsyncTaskWithExecutor(
-      flags, executorBuiltin, operation)
-#endif
-    return Task(task)
-  }
-}
-
-// ==== Unsafe Current Task ----------------------------------------------------
-
 @available(SwiftStdlib 6.0, *)
 @_unavailableInEmbedded
 extension UnsafeCurrentTask {
diff --git a/stdlib/public/Concurrency/Task+immediate.swift.gyb b/stdlib/public/Concurrency/Task+immediate.swift.gyb
new file mode 100644
index 0000000000000..1920d34e996c6
--- /dev/null
+++ b/stdlib/public/Concurrency/Task+immediate.swift.gyb
@@ -0,0 +1,435 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2020-2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import Swift
+@_implementationOnly import SwiftConcurrencyInternalShims
+
+// ==== Task.startSynchronously ------------------------------------------------
+
+% METHOD_VARIANTS = [
+%   'THROWING',
+%   'NON_THROWING',
+% ]
+% for THROWING_VARIANT in METHOD_VARIANTS:
+
+% IS_THROWING = THROWING_VARIANT == 'THROWING'
+% if IS_THROWING:
+%   FAILURE_TYPE = 'Error'
+%   THROWS = 'throws '
+% else:
+%   FAILURE_TYPE = 'Never'
+%   THROWS = ''
+% end
+
+% end
+
+// ==== Task.immediate(Detached) ---------------------------------------------------------
+
+% METHOD_VARIANTS = [
+%   ('immediate', 'THROWING'),
+%   ('immediate', 'NON_THROWING'),
+%   ('immediateDetached', 'THROWING'),
+%   ('immediateDetached', 'NON_THROWING'),
+% ]
+% for (METHOD_NAME, THROWING_VARIANT) in METHOD_VARIANTS:
+
+% IS_THROWING = THROWING_VARIANT == 'THROWING'
+% IS_DETACHED = 'Detached' in METHOD_NAME
+% if IS_THROWING:
+%   FAILURE_TYPE = 'Error'
+%   THROWS = 'throws '
+% else:
+%   FAILURE_TYPE = 'Never'
+%   THROWS = ''
+% end
+
+@available(SwiftStdlib 6.2, *)
+extension Task where Failure == ${FAILURE_TYPE} {
+
+  % if IS_DETACHED:
+  /// Create and immediately start running a new task in the context of the calling thread/task.
+  % else:
+  /// Create and immediately start running a new detached task in the context of the calling thread/task.
+  % end # IS_DETACHED
+  ///
+  /// This function _starts_ the created task on the calling context.
+  /// The task will continue executing on the caller's context until it suspends,
+  /// and after suspension will resume on the adequate executor. For a nonisolated
+  /// operation this means running on the global concurrent pool, and on an isolated
+  /// operation it means the appropriate executor of that isolation context.
+  ///
+  /// As indicated by the lack of `async` on this method, this method does _not_
+  /// suspend, and instead takes over the calling task's (thread's) execution in
+  /// a synchronous manner.
+  ///
+  /// Other than the execution semantics discussed above, the created task
+  /// is semantically equivalent to a task created using
+  % if IS_DETACHED:
+  /// the ``Task/detached`` function.
+  % else:
+  /// the ``Task/init`` initializer.
+  % end
+  ///
+  /// - Parameters:
+  ///   - name: The high-level human-readable name given for this task
+  ///   - priority: The priority of the task.
+  ///     Pass `nil` to use the ``Task/basePriority`` of the current task (if there is one).
+  ///   - taskExecutor: The task executor that the child task should be started on and keep using.
+  ///      Explicitly passing `nil` as the executor preference is equivalent to no preference,
+  ///      and effectively means to inherit the outer context's executor preference.
+  ///      You can also pass the ``globalConcurrentExecutor`` global executor explicitly.
+  ///   - operation: the operation to be run immediately upon entering the task.
+  /// - Returns: A reference to the unstructured task which may be awaited on.
+  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
+  @discardableResult
+  public static func ${METHOD_NAME}(
+    name: String? = nil,
+    priority: TaskPriority? = nil,
+    executorPreference taskExecutor: consuming (any TaskExecutor)? = nil,
+    @_implicitSelfCapture @_inheritActorContext(always) operation: sending @isolated(any) @escaping () async ${THROWS} -> Success
+  ) -> Task<Success, ${FAILURE_TYPE}> {
+
+    let builtinSerialExecutor =
+      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
+
+    // Determine if we're switching isolation dynamically.
+    // If not, we can run the task synchronously and therefore MUST NOT "enqueue" it.
+    let flagsMustNotCrash: UInt64 = 0
+    let canRunSynchronously: Bool =
+    if let builtinSerialExecutor {
+      _taskIsCurrentExecutor(executor: builtinSerialExecutor, flags: flagsMustNotCrash)
+    } else {
+      true // if there is no target executor, we can run synchronously
+    }
+
+    let flags = taskCreateFlags(
+      priority: priority,
+      isChildTask: false,
+      copyTaskLocals: ${'true' if not IS_DETACHED else 'false /* detached */'},
+      inheritContext: ${'true' if not IS_DETACHED else 'false /* detached */'},
+      enqueueJob: !canRunSynchronously,
+      addPendingGroupTaskUnconditionally: false,
+      isDiscardingTask: false,
+      isSynchronousStart: true
+    )
+
+    var task: Builtin.NativeObject?
+    #if $BuiltinCreateAsyncTaskName
+    if let name {
+      #if $BuiltinCreateAsyncTaskOwnedTaskExecutor
+      task =
+        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
+          Builtin.createTask(
+            flags: flags,
+            initialSerialExecutor: builtinSerialExecutor,
+            initialTaskExecutorConsuming: taskExecutor,
+            taskName: nameBytes.baseAddress!._rawValue,
+            operation: operation).0
+        }
+      #else // no $BuiltinCreateAsyncTaskOwnedTaskExecutor
+      task =
+        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
+          Builtin.createTask(
+            flags: flags,
+            initialSerialExecutor: builtinSerialExecutor,
+            taskName: nameBytes.baseAddress!._rawValue,
+            operation: operation).0
+        }
+      #endif // $BuiltinCreateAsyncTaskOwnedTaskExecutor
+    } // let name
+    #endif // $BuiltinCreateAsyncTaskName
+
+    // Task name was not set, or task name createTask is unavailable
+    if task == nil {
+      assert(name == nil)
+      #if $BuiltinCreateAsyncTaskOwnedTaskExecutor
+      task = Builtin.createTask(
+        flags: flags,
+        initialSerialExecutor: builtinSerialExecutor,
+        initialTaskExecutorConsuming: taskExecutor,
+        operation: operation).0
+      #else
+      // legacy branch for the non-consuming task executor
+      let executorBuiltin: Builtin.Executor =
+        taskExecutor.asUnownedTaskExecutor().executor
+
+      task = Builtin.createTask(
+        flags: flags,
+        initialSerialExecutor: builtinSerialExecutor,
+        initialTaskExecutor: executorBuiltin,
+        operation: operation).0
+      #endif
+    }
+
+    if task == nil {
+      // either no task name was set, or names are unsupported
+      task = Builtin.createTask(
+        flags: flags,
+        initialSerialExecutor: builtinSerialExecutor,
+        operation: operation).0
+    }
+
+    if canRunSynchronously {
+      _startTaskImmediately(task!, targetExecutor: builtinSerialExecutor)
+    }
+    return Task<Success, ${FAILURE_TYPE}>(task!)
+  }
+}
+%end
+
+%{
+GROUP_AND_OP_INFO = [
+   (
+     'TaskGroup',
+     [
+       'addImmediateTask',
+       'addImmediateTaskUnlessCancelled'
+     ],
+     '',
+     'ChildTaskResult'
+   ),
+   (
+     'ThrowingTaskGroup',
+     [
+       'addImmediateTask',
+       'addImmediateTaskUnlessCancelled'
+     ],
+     'throws ',
+     'ChildTaskResult'
+   ),
+   (
+     'DiscardingTaskGroup',
+     [
+       'addImmediateTask',
+       'addImmediateTaskUnlessCancelled'
+     ],
+     '',
+     'Void'
+   ),
+   (
+     'ThrowingDiscardingTaskGroup',
+     [
+       'addImmediateTask',
+       'addImmediateTaskUnlessCancelled'
+     ],
+     'throws ',
+     'Void'
+   ),
+ ]
+}%
+% for (GROUP_TYPE, METHOD_NAMES, THROWS, RESULT_TYPE) in GROUP_AND_OP_INFO:
+%   for METHOD_NAME in METHOD_NAMES:
+%
+% IS_DISCARDING = 'Discarding' in GROUP_TYPE
+% IS_ADD_UNLESS_CANCELLED = METHOD_NAME == "addImmediateTaskUnlessCancelled"
+%
+% ARROW_RETURN_TYPE = "-> Bool " if IS_ADD_UNLESS_CANCELLED else ""
+%
+% if IS_DISCARDING:
+%   TASK_CREATE_FN = 'Builtin.createDiscardingTask'
+% else:
+%   TASK_CREATE_FN = 'Builtin.createTask'
+% end
+
+@available(SwiftStdlib 6.2, *)
+extension ${GROUP_TYPE} {
+
+  /// Add a child task to the group and immediately start running it in the context of the calling thread/task.
+  ///
+  /// This function _starts_ the created task on the calling context.
+  /// The task will continue executing on the caller's context until it suspends,
+  /// and after suspension will resume on the adequate executor. For a nonisolated
+  /// operation this means running on the global concurrent pool, and on an isolated
+  /// operation it means the appropriate executor of that isolation context.
+  ///
+  /// As indicated by the lack of `async` on this method, this method does _not_
+  /// suspend, and instead takes over the calling task's (thread's) execution in
+  /// a synchronous manner.
+  ///
+  /// Other than the execution semantics discussed above, the created task
+  /// is semantically equivalent to its basic version which can be
+  /// created using ``${GROUP_TYPE}/addTask``.
+  ///
+  /// - Parameters:
+  ///   - name: Human readable name of this task.
+  ///   - priority: The priority of the operation task.
+  ///      Omit this parameter or pass `nil` to inherit the task group's base priority.
+  ///   - taskExecutor: The task executor that the child task should be started on and keep using.
+  ///      Explicitly passing `nil` as the executor preference is equivalent to
+  ///      calling the `${METHOD_NAME}` method without a preference, and effectively
+  ///      means to inherit the outer context's executor preference.
+  ///      You can also pass the ``globalConcurrentExecutor`` global executor explicitly.
+  ///   - operation: The operation to execute as part of the task group.
+  % if IS_ADD_UNLESS_CANCELLED:
+  /// - Returns: `true` if the child task was added to the group;
+  ///   otherwise `false`.
+  % end
+  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
+  public mutating func ${METHOD_NAME}( // in ${GROUP_TYPE}
+    name: String? = nil,
+    priority: TaskPriority? = nil,
+    executorPreference taskExecutor: consuming (any TaskExecutor)? = nil,
+    @_inheritActorContext @_implicitSelfCapture operation: sending @isolated(any) @escaping () async ${THROWS}-> ${RESULT_TYPE}
+  ) ${ARROW_RETURN_TYPE}{
+
+    % if IS_ADD_UNLESS_CANCELLED:
+    let canAdd = _taskGroupAddPendingTask(group: _group, unconditionally: false)
+
+    guard canAdd else {
+      // the group is cancelled and is not accepting any new work
+      return false
+    }
+    % end # IS_ADD_UNLESS_CANCELLED
+
+    let flags = taskCreateFlags(
+      priority: priority,
+      isChildTask: true,
+      copyTaskLocals: false,
+      inheritContext: false,
+      enqueueJob: false, // don't enqueue, we'll run it manually
+      % if IS_ADD_UNLESS_CANCELLED:
+      % # In this case, we already added the pending task count before we create the task
+      % # so we must not add to the pending counter again.
+      addPendingGroupTaskUnconditionally: false,
+      % else:
+      addPendingGroupTaskUnconditionally: true,
+      % end
+      isDiscardingTask: ${str(IS_DISCARDING).lower()},
+      isSynchronousStart: true
+    )
+
+    let builtinSerialExecutor =
+      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
+
+    var task: Builtin.NativeObject?
+
+    #if $BuiltinCreateAsyncTaskName
+    if let name {
+      task =
+        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
+          ${TASK_CREATE_FN}(
+            flags: flags,
+            initialSerialExecutor: builtinSerialExecutor,
+            taskGroup: _group,
+            initialTaskExecutorConsuming: taskExecutor,
+            taskName: nameBytes.baseAddress!._rawValue,
+            operation: operation).0
+        }
+    }
+    #endif // $BuiltinCreateAsyncTaskName
+
+    // Task name was not set, or task name createTask is unavailable
+    if task == nil, let taskExecutor {
+      #if $BuiltinCreateAsyncTaskOwnedTaskExecutor
+      task = ${TASK_CREATE_FN}(
+        flags: flags,
+        initialSerialExecutor: builtinSerialExecutor,
+        taskGroup: _group,
+        initialTaskExecutorConsuming: taskExecutor,
+        operation: operation).0
+      #else
+      // legacy branch for the non-consuming task executor
+      let executorBuiltin: Builtin.Executor =
+        taskExecutor.asUnownedTaskExecutor().executor
+
+      task = ${TASK_CREATE_FN}(
+        flags: flags,
+        initialSerialExecutor: builtinSerialExecutor,
+        taskGroup: _group,
+        initialTaskExecutor: executorBuiltin,
+        operation: operation).0
+      #endif
+    }
+
+    if task == nil {
+      task = ${TASK_CREATE_FN}(
+        flags: flags,
+        initialSerialExecutor: builtinSerialExecutor,
+        taskGroup: _group,
+        operation: operation).0
+    }
+
+    // Assert that we did create the task, but there's no need to store it,
+    // as it was added to the group itself.
+    assert(task != nil, "Expected task to be created!")
+
+    _startTaskImmediately(task!, targetExecutor: builtinSerialExecutor)
+
+    % if IS_ADD_UNLESS_CANCELLED:
+    return true // task successfully enqueued
+    % end
+  }
+}
+%   end # METHOD_NAMES
+%end # GROUP_TYPES
+
+// ==== Legacy SPI -------------------------------------------------------------
+
+% METHOD_VARIANTS = [
+%   'THROWING',
+%   'NON_THROWING',
+% ]
+% for THROWING_VARIANT in METHOD_VARIANTS:
+
+% IS_THROWING = THROWING_VARIANT == 'THROWING'
+% if IS_THROWING:
+%   FAILURE_TYPE = 'Error'
+%   THROWS = 'throws '
+% else:
+%   FAILURE_TYPE = 'Never'
+%   THROWS = ''
+% end
+
+#if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY && !SWIFT_CONCURRENCY_EMBEDDED
+@available(SwiftStdlib 5.9, *)
+extension Task where Failure == ${FAILURE_TYPE} {
+
+  @_spi(MainActorUtilities)
+  @MainActor
+  @available(SwiftStdlib 5.9, *)
+  @discardableResult
+  @available(*, deprecated, renamed: "immediate")
+  public static func startOnMainActor(
+    priority: TaskPriority? = nil,
+    @_inheritActorContext @_implicitSelfCapture _ operation: __owned @Sendable @escaping @MainActor () async ${THROWS} -> Success
+  ) -> Task<Success, ${FAILURE_TYPE}> {
+    let flags = taskCreateFlags(
+      priority: priority,
+      isChildTask: false,
+      copyTaskLocals: true,
+      inheritContext: true,
+      enqueueJob: false,
+      addPendingGroupTaskUnconditionally: false,
+      isDiscardingTask: false,
+      isSynchronousStart: false
+    )
+
+    let (task, _) = Builtin.createAsyncTask(flags, operation)
+    _startTaskOnMainActor(task)
+
+    return Task<Success, ${FAILURE_TYPE}>(task)
+  }
+}
+#endif
+% end
+
+// Internal Runtime Functions --------------------------------------------------
+
+@_silgen_name("swift_task_startOnMainActor")
+internal func _startTaskOnMainActor(_ task: Builtin.NativeObject)
+
+@available(SwiftStdlib 6.2, *)
+@_silgen_name("swift_task_immediate")
+@usableFromInline
+internal func _startTaskImmediately(_ task: Builtin.NativeObject, targetExecutor: Builtin.Executor?)
diff --git a/stdlib/public/Concurrency/Task+init.swift.gyb b/stdlib/public/Concurrency/Task+init.swift.gyb
new file mode 100644
index 0000000000000..36a2e597e0be3
--- /dev/null
+++ b/stdlib/public/Concurrency/Task+init.swift.gyb
@@ -0,0 +1,415 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import Swift
+
+% for (METHOD_VARIANTS, ALL_AVAILABILITY, PARAMS) in [
+%   # ==== -------------------------------------------------------------------------------------------------------------
+%   # ==== Without task executor, but available ever since 5.1
+%   ([ # METHOD_VARIANT
+%      'init',
+%      'init/*throws*/',
+%   ],
+%   [ # ALL_AVAILABILITY
+%     '@_alwaysEmitIntoClient',
+%     '@available(SwiftStdlib 5.1, *)',
+%   ],
+%   [ # PARAMS
+%     'name: String? = nil',
+%     'priority: TaskPriority? = nil',
+%     '@_inheritActorContext @_implicitSelfCapture operation: sending @escaping @isolated(any) () async throws -> Success',
+%   ]),
+%   # ==== --------------------------------------------------------------------
+%   ([ # METHOD_VARIANT
+%      'static func detached',
+%      'static func detached/*throws*/',
+%   ],
+%   [
+%     '@_alwaysEmitIntoClient',
+%     '@available(SwiftStdlib 5.1, *)',
+%   ],
+%   [ # PARAMS
+%     'name: String? = nil',
+%     'priority: TaskPriority? = nil',
+%     'operation: sending @escaping @isolated(any) () async throws -> Success',
+%   ]),
+%   # ==== -------------------------------------------------------------------------------------------------------------
+%   # ==== With task executor, but available only since 6.0
+%   ([ # METHOD_VARIANT
+%      'init',
+%      'init/*throws*/',
+%   ],
+%   [ # ALL_AVAILABILITY
+%     '@_alwaysEmitIntoClient',
+%     '@available(SwiftStdlib 6.0, *)',
+%   ],
+%   [ # PARAMS
+%     'name: String? = nil',
+%     'executorPreference taskExecutor: (any TaskExecutor)?',
+%     'priority: TaskPriority? = nil',
+%     'operation: sending @escaping () async throws -> Success',
+%   ]),
+%   # ==== --------------------------------------------------------------------
+%   ([ # METHOD_VARIANT
+%      'static func detached',
+%      'static func detached/*throws*/',
+%   ],
+%   [
+%     '@_alwaysEmitIntoClient',
+%     '@available(SwiftStdlib 6.0, *)',
+%   ],
+%   [ # PARAMS
+%     'name: String? = nil',
+%     'executorPreference taskExecutor: (any TaskExecutor)?',
+%     'priority: TaskPriority? = nil',
+%     'operation: sending @escaping () async throws -> Success',
+%   ]),
+%   # !!!! -------------------------------------------------------------------------------------------------------------
+%   # !!!! Legacy / Source Compatibility "Shims"
+%   # !!!!
+%   # !!!! These legacy APIs technically did not have @isolated(any) but since they're all emit-into-client,
+%   # !!!! we just allow them to become slightly better here. It makes source generation simpler, and doesn't really hurt.
+%   # !!!! -------------------------------------------------------------------------------------------------------------
+%   # ==== Legacy API: Global 'detach' function
+%   ([ # METHOD_VARIANT
+%      'func detach<Success>',
+%      'func detach<Success>/*throws*/',
+%   ],
+%   [ # ALL_AVAILABILITY
+%     '@_alwaysEmitIntoClient',
+%     '@available(SwiftStdlib 5.1, *)',
+%     '@available(*, deprecated, message: "`detach` was replaced by `Task.detached` and will be removed shortly.")',
+%   ],
+%   [ # PARAMS
+%     'priority: TaskPriority? = nil',
+%     '@_inheritActorContext @_implicitSelfCapture operation: __owned @Sendable @escaping @isolated(any) () async throws -> Success',
+%   ]),
+%   # ==== Legacy API: runDetached
+%   ([ # METHOD_VARIANT
+%      'static func runDetached',
+%      'static func runDetached/*throws*/',
+%   ],
+%   [ # ALL_AVAILABILITY
+%     '@_alwaysEmitIntoClient',
+%     '@available(SwiftStdlib 5.1, *)',
+%     '@available(*, deprecated, message: "`Task.runDetached` was replaced by `Task.detached` and will be removed shortly.")',
+%   ],
+%   [ # PARAMS
+%     'priority: TaskPriority? = nil',
+%     '@_inheritActorContext @_implicitSelfCapture operation: __owned @Sendable @escaping @isolated(any) () async throws -> Success',
+%   ]),
+%   # ==== Legacy API: asyncDetached
+%   ([ # METHOD_VARIANT
+%      'func asyncDetached<Success>',
+%      'func asyncDetached<Success>/*throws*/',
+%   ],
+%   [ # ALL_AVAILABILITY
+%     '@_alwaysEmitIntoClient',
+%     '@available(SwiftStdlib 5.1, *)',
+%     '@available(*, deprecated, message: "`asyncDetached` was replaced by `Task.detached` and will be removed shortly.")',
+%   ],
+%   [ # PARAMS
+%     'priority: TaskPriority? = nil',
+%     '@_inheritActorContext @_implicitSelfCapture operation: __owned @Sendable @escaping @isolated(any) () async throws -> Success',
+%   ]),
+%   # ==== Legacy API: async
+%   ([ # METHOD_VARIANT
+%      'func async<Success>',
+%      'func async<Success>/*throws*/',
+%   ],
+%   [ # ALL_AVAILABILITY
+%     '@_alwaysEmitIntoClient',
+%     '@available(SwiftStdlib 5.1, *)',
+%     '@available(*, deprecated, message: "`async` was replaced by `Task.init` and will be removed shortly.")',
+%   ],
+%   [ # PARAMS
+%     'priority: TaskPriority? = nil',
+%     '@_inheritActorContext @_implicitSelfCapture operation: __owned @Sendable @escaping @isolated(any) () async throws -> Success',
+%   ]),
+% ]:
+% for METHOD_VARIANT in METHOD_VARIANTS:
+
+% IS_TOP_LEVEL_FUNC = (not ('init' in METHOD_VARIANT)) and (not ('static' in METHOD_VARIANT))
+% IS_INIT = 'init' in METHOD_VARIANT
+% IS_DETACHED = 'detach' in METHOD_VARIANT.lower()
+% IS_THROWING = 'throws' in METHOD_VARIANT
+% 
+% HAS_TASK_PRIORITY = any('priority:' in param for param in PARAMS)
+% HAS_TASK_NAME = any('name:' in param for param in PARAMS)
+% HAS_TASK_EXECUTOR = any('taskExecutor:' in param for param in PARAMS)
+% HAS_ISOLATED_ANY = any('@isolated(any)' in param for param in PARAMS)
+% IS_DEPRECATED = any('deprecated' in a for a in ALL_AVAILABILITY)
+%
+% if IS_THROWING:
+%   FAILURE_TYPE = 'Error'
+% else:
+%   FAILURE_TYPE = 'Never'
+% end
+
+%{
+
+def adjust_params_for_kind(params):
+  res = []
+  for p in params:
+    np = p
+    if not IS_THROWING:
+      np = np.replace("throws", "")
+    res.append(np)
+  return res
+
+def adjust_availability(avails):
+  res = []
+  for av in avails:
+    adjusted = av
+    if HAS_TASK_EXECUTOR:
+      adjusted = adjusted.replace("SwiftStdlib 5.1", "SwiftStdlib 6.0")
+    res.append(adjusted)
+  return res
+
+if IS_INIT:
+  ARROW_RETURN_TYPE = '' # init does not spell out return type
+else:
+  ARROW_RETURN_TYPE = f'-> Task<Success, {FAILURE_TYPE}>'
+
+}%
+
+% # ====================================================================================================================
+% if not IS_TOP_LEVEL_FUNC:
+extension Task where Failure == ${FAILURE_TYPE} {
+% end
+
+% # --------------------------------------------------------------------------------------------------------------------
+#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+  @discardableResult
+  @_alwaysEmitIntoClient
+  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
+  public ${METHOD_VARIANT}(
+      ${",\n    ".join(adjust_params_for_kind(PARAMS))}
+    ) ${ARROW_RETURN_TYPE}{
+    fatalError("Unavailable in task-to-thread concurrency model.")
+  }
+
+% # --------------------------------------------------------------------------------------------------------------------
+% if not HAS_TASK_EXECUTOR:
+#elseif $Embedded
+  @discardableResult
+  @_alwaysEmitIntoClient
+  ${"  \n".join(adjust_availability(['@available(SwiftStdlib 5.1, *)']))}
+  public ${METHOD_VARIANT}(
+      ${",\n    ".join(adjust_params_for_kind(PARAMS))}
+    ) ${ARROW_RETURN_TYPE}{
+    // Set up the job flags for a new task.
+    let flags = taskCreateFlags(
+      priority: priority,
+      isChildTask: false,
+      copyTaskLocals: ${'true' if not IS_DETACHED else 'false /* detached */'},
+      inheritContext: ${'true' if not IS_DETACHED else 'false /* detached */'},
+      enqueueJob: true,
+      addPendingGroupTaskUnconditionally: false,
+      isDiscardingTask: false,
+      isSynchronousStart: false)
+
+    let (task, _) = Builtin.createAsyncTask(flags, operation)
+
+    % if IS_INIT:
+    self._task = task
+    % else:
+    return Task(task)
+    % end
+  }
+% end # not HAS_TASK_EXECUTOR
+
+% # --------------------------------------------------------------------------------------------------------------------
+#else
+
+% if IS_DEPRECATED:
+/// Deprecated, available only for source compatibility reasons.
+% else:
+% # We skip documentation for the legacy APIs which are just here for source compatibility reasons.
+% if IS_THROWING:
+  /// Runs the given throwing operation asynchronously
+% else:
+  /// Runs the given nonthrowing operation asynchronously
+% end
+% if IS_DETACHED:
+  /// as part of a new _unstructured_ _detached_ top-level task.
+% else:
+  /// as part of a new _unstructured_ top-level task.
+% end
+  ///
+% if IS_THROWING:
+  /// If the `operation` throws an error, it is caught by the `Task` and will be
+  /// rethrown only when the task's `value` is awaited. Take care to not accidentally
+  /// dismiss errors by not awaiting on the task's resulting value.
+% end
+  ///
+% if IS_DETACHED:
+  /// Don't use a detached unstructured task if it's possible
+  /// to model the operation using structured concurrency features like child tasks.
+  /// Child tasks inherit the parent task's priority and task-local storage,
+  /// and canceling a parent task automatically cancels all of its child tasks.
+  /// You need to handle these considerations manually with a detached task.
+% end
+  ///
+  /// You need to keep a reference to the task
+  /// if you want to cancel it by calling the `Task.cancel()` method.
+  /// Discarding your reference to a task
+  /// doesn't implicitly cancel that task,
+  /// it only makes it impossible for you to explicitly cancel the task.
+  ///
+  /// - Parameters:
+  % if HAS_TASK_NAME:
+  ///   - name: Human readable name of the task.
+  % end
+  % if HAS_TASK_EXECUTOR:
+  ///   - taskExecutor: The task executor that the child task should be started on and keep using.
+  ///      Explicitly passing `nil` as the executor preference is equivalent to no preference,
+  ///      and effectively means to inherit the outer context's executor preference.
+  ///      You can also pass the ``globalConcurrentExecutor`` global executor explicitly.
+  % end
+  ///   - priority: The priority of the operation task.
+  % if IS_DETACHED:
+  ///       Omit this parameter or pass `nil` to inherit the enclosing context's base priority.
+  % end
+  ///   - operation: The operation to perform.
+  ///
+  /// - Returns: A reference to the task.
+% end # IS_DEPRECATED
+  ${"\n  ".join(adjust_availability(ALL_AVAILABILITY))}
+  @discardableResult
+  public ${METHOD_VARIANT}( // Task ${METHOD_VARIANT}
+    ${",\n    ".join(adjust_params_for_kind(PARAMS))}
+  ) ${ARROW_RETURN_TYPE}{
+
+    // Set up the job flags for a new task.
+    let flags = taskCreateFlags(
+      priority: priority,
+      isChildTask: false,
+      copyTaskLocals: ${'true' if not IS_DETACHED else 'false /* detached */'},
+      inheritContext: ${'true' if not IS_DETACHED else 'false /* detached */'},
+      enqueueJob: true,
+      addPendingGroupTaskUnconditionally: false,
+      isDiscardingTask: false,
+      isSynchronousStart: false)
+
+% if HAS_ISOLATED_ANY:
+    let builtinSerialExecutor =
+      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
+% end # HAS_ISOLATED_ANY
+
+    var task: Builtin.NativeObject?
+% if HAS_TASK_NAME:
+    #if $BuiltinCreateAsyncTaskName
+    if let name {
+      % if HAS_TASK_EXECUTOR:
+      #if $BuiltinCreateAsyncTaskOwnedTaskExecutor
+      task =
+        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
+          Builtin.createTask(
+            flags: flags,
+            % if HAS_ISOLATED_ANY:
+            initialSerialExecutor: builtinSerialExecutor,
+            % end
+            % if HAS_TASK_EXECUTOR:
+            initialTaskExecutorConsuming: taskExecutor,
+            % end
+            taskName: nameBytes.baseAddress!._rawValue,
+            operation: operation).0
+        }
+      #else // no $BuiltinCreateAsyncTaskOwnedTaskExecutor
+      // legacy branch for the non-consuming task executor
+      let executorBuiltin: Builtin.Executor =
+        taskExecutor.asUnownedTaskExecutor().executor
+      task =
+        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
+          Builtin.createTask(
+            flags: flags,
+            % if HAS_ISOLATED_ANY:
+            initialSerialExecutor: builtinSerialExecutor,
+            % end
+            initialTaskExecutor: executorBuiltin,
+            taskName: nameBytes.baseAddress!._rawValue,
+            operation: operation).0
+        }
+      #endif // $BuiltinCreateAsyncTaskOwnedTaskExecutor
+      % else: # if no TASK_EXECUTOR
+      task =
+        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
+          Builtin.createTask(
+            flags: flags,
+            % if HAS_ISOLATED_ANY:
+            initialSerialExecutor: builtinSerialExecutor,
+            % end
+            taskName: nameBytes.baseAddress!._rawValue,
+            operation: operation).0
+        }
+      % end # if no HAS_TASK_EXECUTOR
+    } // let name
+    #endif // $BuiltinCreateAsyncTaskName
+% end # HAS_TASK_NAME
+
+% if HAS_TASK_EXECUTOR:
+    // Task name was not set, or task name createTask is unavailable
+    if task == nil {
+      assert(name == nil)
+      #if $BuiltinCreateAsyncTaskOwnedTaskExecutor
+      task = Builtin.createTask(
+        flags: flags,
+        % if HAS_ISOLATED_ANY:
+        initialSerialExecutor: builtinSerialExecutor,
+        % end
+        initialTaskExecutorConsuming: taskExecutor,
+        operation: operation).0
+      #else
+      // legacy branch for the non-consuming task executor
+      let executorBuiltin: Builtin.Executor =
+        taskExecutor.asUnownedTaskExecutor().executor
+
+      task = Builtin.createTask(
+        flags: flags,
+        % if HAS_ISOLATED_ANY:
+        initialSerialExecutor: builtinSerialExecutor,
+        % end
+        initialTaskExecutor: executorBuiltin,
+        operation: operation).0
+      #endif
+    }
+% end # HAS_TASK_EXECUTOR
+
+    if task == nil {
+      // either no task name was set, or names are unsupported
+      task = Builtin.createTask(
+      flags: flags,
+      % if HAS_ISOLATED_ANY:
+      initialSerialExecutor: builtinSerialExecutor,
+      % end
+      operation: operation).0
+    }
+
+% if IS_INIT:
+    self._task = task!
+% else:
+    return Task(task!)
+% end
+  }
+
+#endif
+
+% if not IS_TOP_LEVEL_FUNC:
+} // extension Task ...
+% end
+
+% end
+% end
+
+// =====================================================================================================================
+// =====================================================================================================================
diff --git a/stdlib/public/Concurrency/Task+startSynchronously.swift.gyb b/stdlib/public/Concurrency/Task+startSynchronously.swift.gyb
deleted file mode 100644
index 30c55da989f40..0000000000000
--- a/stdlib/public/Concurrency/Task+startSynchronously.swift.gyb
+++ /dev/null
@@ -1,244 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2020-2025 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import Swift
-@_implementationOnly import SwiftConcurrencyInternalShims
-
-// ==== Task.startSynchronously ------------------------------------------------
-
-% METHOD_VARIANTS = [
-%   'THROWING',
-%   'NON_THROWING',
-% ]
-% OPERATION_PARAM = '@_inheritActorContext @_implicitSelfCapture _ operation: __owned @Sendable @escaping () async throws -> Success'
-% for METHOD_VARIANT in METHOD_VARIANTS:
-
-% IS_THROWING = METHOD_VARIANT == 'THROWING'
-% if IS_THROWING:
-%   FAILURE_TYPE = 'Error'
-% else:
-%   FAILURE_TYPE = 'Never'
-% end
-
-@available(SwiftStdlib 6.2, *)
-extension Task where Failure == ${FAILURE_TYPE} {
-
-  /// Create and immediately start running a new task in the context of the calling thread/task.
-  ///
-  /// This function _starts_ the created task on the calling context.
-  /// The task will continue executing on the caller's context until it suspends,
-  /// and after suspension will resume on the adequate executor. For a nonisolated
-  /// operation this means running on the global concurrent pool, and on an isolated
-  /// operation it means the appropriate executor of that isolation context.
-  ///
-  /// As indicated by the lack of `async` on this method, this method does _not_
-  /// suspend, and instead takes over the calling task's (thread's) execution in
-  /// a synchronous manner.
-  ///
-  /// Other than the execution semantics discussed above, the created task
-  /// is semantically equivalent to its basic version which can be
-  /// created using ``Task/init``.
-  ///
-  /// - Parameters:
-  ///   - name: The high-level human-readable name given for this task
-  ///   - priority: The priority of the task.
-  ///     Pass `nil` to use the ``Task/basePriority`` of the current task (if there is one).
-  ///   - operation: the operation to be run immediately upon entering the task.
-  /// - Returns: A reference to the unstructured task which may be awaited on.
-  @available(SwiftStdlib 6.2, *)
-  @discardableResult
-  public static func startSynchronously(
-    name: String? = nil,
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture _ operation: __owned sending @escaping () async throws -> Success
-  ) -> Task<Success, ${FAILURE_TYPE}> {
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: false,
-      copyTaskLocals: true,
-      inheritContext: true,
-      enqueueJob: false, // don't enqueue, we'll run it manually
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false,
-      isSynchronousStart: true
-    )
-
-    var task: Builtin.NativeObject?
-    #if $BuiltinCreateAsyncTaskName
-    if let name {
-      task =
-        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
-          Builtin.createTask(
-            flags: flags,
-            taskName: nameBytes.baseAddress!._rawValue,
-            operation: operation).0
-        }
-    }
-    #endif
-    if task == nil {
-      // either no task name was set, or names are unsupported
-      task = Builtin.createTask(
-        flags: flags,
-        operation: operation).0
-    }
-
-    _startTaskSynchronously(task!)
-    return Task<Success, ${FAILURE_TYPE}>(task!)
-  }
-}
-%end
-
-%{
-GROUP_AND_OP_INFO = [
-   (
-     'TaskGroup',
-     [
-       'startTaskSynchronously',
-       'startTaskSynchronouslyUnlessCancelled'
-     ],
-     '',
-     'ChildTaskResult'
-   ),
-   (
-     'ThrowingTaskGroup',
-     [
-       'startTaskSynchronously',
-       'startTaskSynchronouslyUnlessCancelled'
-     ],
-     'throws ',
-     'ChildTaskResult'
-   ),
-   (
-     'DiscardingTaskGroup',
-     [
-       'startTaskSynchronously',
-       'startTaskSynchronouslyUnlessCancelled'
-     ],
-     '',
-     'Void'
-   ),
-   (
-     'ThrowingDiscardingTaskGroup',
-     [
-       'startTaskSynchronously',
-       'startTaskSynchronouslyUnlessCancelled'
-     ],
-     'throws ',
-     'Void'
-   ),
- ]
-}%
-% for (GROUP_TYPE, METHOD_NAMES, THROWS, RESULT_TYPE) in GROUP_AND_OP_INFO:
-%   for METHOD_NAME in METHOD_NAMES:
-@available(SwiftStdlib 6.2, *)
-extension ${GROUP_TYPE} {
-
-  /// Create and immediately start running a new child task in the context of the calling thread/task.
-  ///
-  /// This function _starts_ the created task on the calling context.
-  /// The task will continue executing on the caller's context until it suspends,
-  /// and after suspension will resume on the adequate executor. For a nonisolated
-  /// operation this means running on the global concurrent pool, and on an isolated
-  /// operation it means the appropriate executor of that isolation context.
-  ///
-  /// As indicated by the lack of `async` on this method, this method does _not_
-  /// suspend, and instead takes over the calling task's (thread's) execution in
-  /// a synchronous manner.
-  ///
-  /// Other than the execution semantics discussed above, the created task
-  /// is semantically equivalent to its basic version which can be
-  /// created using ``${GROUP_TYPE}/addTask``.
-  @available(SwiftStdlib 6.2, *)
-  public func ${METHOD_NAME}( // in ${GROUP_TYPE}
-    name: String? = nil,
-    priority: TaskPriority? = nil,
-    operation: sending @escaping () async ${THROWS}-> ${RESULT_TYPE}
-  ) {
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: true,
-      copyTaskLocals: false,
-      inheritContext: false,
-      enqueueJob: false, // don't enqueue, we'll run it manually
-      addPendingGroupTaskUnconditionally: true,
-      isDiscardingTask: ${'true' if 'Discarding' in GROUP_TYPE else 'false'},
-      isSynchronousStart: true
-    )
-
-    // Create the task in this group.
-    let (task, _) = Builtin.createTask(
-      flags: flags,
-      taskGroup: self._group,
-      operation: operation
-    )
-    _startTaskSynchronously(task)
-  }
-}
-%   end # METHOD_NAMES
-%end # GROUP_TYPES
-
-// ==== Legacy SPI -------------------------------------------------------------
-
-% METHOD_VARIANTS = [
-%   'THROWING',
-%   'NON_THROWING',
-% ]
-% OPERATION_PARAM = '@_inheritActorContext @_implicitSelfCapture _ operation: __owned @Sendable @escaping @MainActor () async throws -> Success'
-% for METHOD_VARIANT in METHOD_VARIANTS:
-
-% IS_THROWING = METHOD_VARIANT == 'THROWING'
-% if IS_THROWING:
-%   FAILURE_TYPE = 'Error'
-% else:
-%   FAILURE_TYPE = 'Never'
-%   OPERATION_PARAM = OPERATION_PARAM.replace('throws', '')
-% end
-
-#if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY && !SWIFT_CONCURRENCY_EMBEDDED
-@available(SwiftStdlib 5.9, *)
-extension Task where Failure == ${FAILURE_TYPE} {
-
-  @_spi(MainActorUtilities)
-  @MainActor
-  @available(SwiftStdlib 5.9, *)
-  @discardableResult
-  public static func startOnMainActor(
-    priority: TaskPriority? = nil,
-    ${OPERATION_PARAM}
-  ) -> Task<Success, ${FAILURE_TYPE}> {
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: false,
-      copyTaskLocals: true,
-      inheritContext: true,
-      enqueueJob: false,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false,
-      isSynchronousStart: false
-    )
-
-    let (task, _) = Builtin.createAsyncTask(flags, operation)
-    _startTaskOnMainActor(task)
-
-    return Task<Success, ${FAILURE_TYPE}>(task)
-  }
-}
-#endif
-% end
-
-// Internal Runtime Functions --------------------------------------------------
-
-@_silgen_name("swift_task_startOnMainActor")
-internal func _startTaskOnMainActor(_ task: Builtin.NativeObject)
-
-@_silgen_name("swift_task_startSynchronously")
-internal func _startTaskSynchronously(_ task: Builtin.NativeObject)
diff --git a/stdlib/public/Concurrency/Task.cpp b/stdlib/public/Concurrency/Task.cpp
index 1b0de154e2f49..3f77983c4301b 100644
--- a/stdlib/public/Concurrency/Task.cpp
+++ b/stdlib/public/Concurrency/Task.cpp
@@ -30,12 +30,12 @@
 #include "swift/ABI/Metadata.h"
 #include "swift/ABI/Task.h"
 #include "swift/ABI/TaskOptions.h"
+#include "swift/Basic/Casting.h"
 #include "swift/Basic/Lazy.h"
 #include "swift/Runtime/Concurrency.h"
 #include "swift/Runtime/EnvironmentVariables.h"
 #include "swift/Runtime/HeapObject.h"
 #include "swift/Runtime/Heap.h"
-#include "swift/Runtime/STLCompatibility.h"
 #include "swift/Threading/Mutex.h"
 #include <atomic>
 #include <new>
@@ -382,6 +382,11 @@ static SerialExecutorRef executorForEnqueuedJob(Job *job) {
     return swift_task_getMainExecutor();
   }
 
+  if (auto identity = reinterpret_cast<HeapObject *>(jobQueue)) {
+    return SerialExecutorRef::forOrdinary(
+      identity, _swift_task_getDispatchQueueSerialExecutorWitnessTable());
+  }
+
   return SerialExecutorRef::generic();
 #endif
 }
@@ -441,6 +446,8 @@ const void *const swift::_swift_concurrency_debug_jobMetadata =
 const void *const swift::_swift_concurrency_debug_asyncTaskMetadata =
     static_cast<Metadata *>(&taskHeapMetadata);
 
+const size_t swift::_swift_concurrency_debug_asyncTaskSize = sizeof(AsyncTask);
+
 const HeapMetadata *swift::jobHeapMetadataPtr =
     static_cast<HeapMetadata *>(&jobHeapMetadata);
 const HeapMetadata *swift::taskHeapMetadataPtr =
@@ -857,7 +864,7 @@ swift_task_create_commonImpl(size_t rawTaskCreateFlags,
 
   } else if (taskIsUnstructured(taskCreateFlags, jobFlags)) {
      SWIFT_TASK_DEBUG_LOG("Creating an unstructured task from %p%s", currentTask,
-                          taskCreateFlags.isSynchronousStartTask() ? " [start synchronously]" : "");
+                          taskCreateFlags.isImmediateTask() ? " [immediate]" : "");
 
     if (isUnspecified(basePriority)) {
       // Case 1: No priority specified
@@ -1059,6 +1066,8 @@ swift_task_create_commonImpl(size_t rawTaskCreateFlags,
   // Initialize the parent context pointer to null.
   initialContext->Parent = nullptr;
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wcast-function-type-mismatch"
   // Initialize the resumption funclet pointer (async return address) to
   // the final funclet for completing the task.
 
@@ -1072,20 +1081,21 @@ swift_task_create_commonImpl(size_t rawTaskCreateFlags,
   // The final funclet shouldn't release the task or the task function.
   } else if (asyncLet) {
     initialContext->ResumeParent =
-        std::bit_cast<TaskContinuationFunction *>(&completeTask);
+        function_cast<TaskContinuationFunction *>(&completeTask);
 
   // If we have a non-null closure context and the task function is not
   // consumed by calling it, use a final funclet that releases both the
   // task and the closure context.
   } else if (closureContext && !taskCreateFlags.isTaskFunctionConsumed()) {
     initialContext->ResumeParent =
-        std::bit_cast<TaskContinuationFunction *>(&completeTaskWithClosure);
+        function_cast<TaskContinuationFunction *>(&completeTaskWithClosure);
 
   // Otherwise, just release the task.
   } else {
     initialContext->ResumeParent =
-        std::bit_cast<TaskContinuationFunction *>(&completeTaskAndRelease);
+        function_cast<TaskContinuationFunction *>(&completeTaskAndRelease);
   }
+#pragma clang diagnostic pop
 
   // Initialize the task-local allocator and our other private runtime
   // state for the task.
@@ -1753,7 +1763,8 @@ swift_task_addCancellationHandlerImpl(
     void *context) {
   void *allocation =
       swift_task_alloc(sizeof(CancellationNotificationStatusRecord));
-  auto unsigned_handler = swift_auth_code(handler, 3848);
+  auto unsigned_handler = swift_auth_code(handler,
+      SpecialPointerAuthDiscriminators::CancellationNotificationFunction);
   auto *record = ::new (allocation)
       CancellationNotificationStatusRecord(unsigned_handler, context);
 
@@ -1792,9 +1803,10 @@ static void swift_task_removeCancellationHandlerImpl(
     return;
   }
 
-  if (auto poppedRecord =
-      popStatusRecordOfType<CancellationNotificationStatusRecord>(swift_task_getCurrent())) {
-    assert(record == poppedRecord && "The removed record did not match the expected record!");
+  auto task = swift_task_getCurrent();
+  assert(task->_private()._status().load(std::memory_order_relaxed).getInnermostRecord() == record &&
+    "We expect that the popped record will be exactly first as well as that it is of the expected type");
+  if (popStatusRecordOfType<CancellationNotificationStatusRecord>(task)) {
     swift_task_dealloc(record);
   }
 }
@@ -1806,8 +1818,10 @@ swift_task_addPriorityEscalationHandlerImpl(
     void *context) {
   void *allocation =
       swift_task_alloc(sizeof(EscalationNotificationStatusRecord));
+  auto unsigned_handler = swift_auth_code(handler,
+      SpecialPointerAuthDiscriminators::EscalationNotificationFunction);
   auto *record = ::new (allocation)
-      EscalationNotificationStatusRecord(handler, context);
+      EscalationNotificationStatusRecord(unsigned_handler, context);
 
   addStatusRecordToSelf(record, [&](ActiveTaskStatus oldStatus, ActiveTaskStatus& newStatus) {
     return true;
@@ -1861,6 +1875,60 @@ static void swift_task_startOnMainActorImpl(AsyncTask* task) {
   _swift_task_setCurrent(originalTask);
 }
 
+// ==== Load-time setup code ----------------------------------------------------
+//
+// The ctor below is placed here so that it must always be linked into the final
+// image even if the libswift_Concurrency is linked in as a static library.
+
+#if !SWIFT_CONCURRENCY_EMBEDDED
+
+// Helper macros for figuring out the mangled name of a context descriptor.
+#define DESCRIPTOR_MANGLING_SUFFIX_Structure Mn
+#define DESCRIPTOR_MANGLING_SUFFIX_Class Mn
+#define DESCRIPTOR_MANGLING_SUFFIX_Enum Mn
+#define DESCRIPTOR_MANGLING_SUFFIX_Protocol Mp
+
+#define DESCRIPTOR_MANGLING_SUFFIX_(X) X
+#define DESCRIPTOR_MANGLING_SUFFIX(KIND)                                       \
+  DESCRIPTOR_MANGLING_SUFFIX_(DESCRIPTOR_MANGLING_SUFFIX_##KIND)
+
+#define DESCRIPTOR_MANGLING_(CHAR, SUFFIX) $sSc##CHAR##SUFFIX
+#define DESCRIPTOR_MANGLING(CHAR, SUFFIX) DESCRIPTOR_MANGLING_(CHAR, SUFFIX)
+
+// Declare context descriptors for all of the concurrency descriptors with
+// standard manglings.
+#define STANDARD_TYPE(KIND, MANGLING, TYPENAME)
+#define STANDARD_TYPE_CONCURRENCY(KIND, MANGLING, TYPENAME)                    \
+  extern "C" const swift::ContextDescriptor DESCRIPTOR_MANGLING(               \
+      MANGLING, DESCRIPTOR_MANGLING_SUFFIX(KIND));
+#include "swift/Demangling/StandardTypesMangling.def"
+
+// Defined in Swift, redeclared here so we can register it with the runtime.
+extern "C" SWIFT_CC(swift)
+bool _swift_task_isCurrentGlobalActor(
+    const swift::Metadata *, const swift::WitnessTable *);
+
+// Register our type descriptors with standard manglings when the concurrency
+// runtime is loaded. This allows the runtime to quickly resolve those standard
+// manglings.
+SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_BEGIN
+__attribute__((constructor)) static void setupStandardConcurrencyDescriptors() {
+  static const swift::ConcurrencyStandardTypeDescriptors descriptors = {
+#define STANDARD_TYPE(KIND, MANGLING, TYPENAME)
+#define STANDARD_TYPE_CONCURRENCY(KIND, MANGLING, TYPENAME)                    \
+  &DESCRIPTOR_MANGLING(MANGLING, DESCRIPTOR_MANGLING_SUFFIX(KIND)),
+#include "swift/Demangling/StandardTypesMangling.def"
+  };
+  _swift_registerConcurrencyRuntime(
+      &descriptors,
+      &_swift_task_isCurrentGlobalActor);
+}
+SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_END
+
+#endif
+
+// ==== Back-deploy hooks -------------------------------------------------------
+
 #define OVERRIDE_TASK COMPATIBILITY_OVERRIDE
 
 #ifdef SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT
diff --git a/stdlib/public/Concurrency/Task.swift b/stdlib/public/Concurrency/Task.swift
index 044571a82a702..3d2b9caaf572a 100644
--- a/stdlib/public/Concurrency/Task.swift
+++ b/stdlib/public/Concurrency/Task.swift
@@ -261,7 +261,7 @@ extension Task where Failure == Never {
 @available(SwiftStdlib 5.1, *)
 extension Task: Hashable {
   public func hash(into hasher: inout Hasher) {
-    unsafe UnsafeRawPointer(Builtin.bridgeToRawPointer(_task)).hash(into: &hasher)
+    UnsafeRawPointer(Builtin.bridgeToRawPointer(_task)).hash(into: &hasher)
   }
 }
 
@@ -580,631 +580,6 @@ func taskCreateFlags(
   return bits
 }
 
-// ==== Task Creation ----------------------------------------------------------
-
-@available(SwiftStdlib 5.1, *)
-extension Task where Failure == Never {
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-  public init(
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping @isolated(any) () async -> Success
-  ) {
-    fatalError("Unavailable in task-to-thread concurrency model.")
-  }
-#else
-  /// Runs the given nonthrowing operation asynchronously
-  /// as part of a new top-level task on behalf of the current actor.
-  ///
-  /// Use this function when creating asynchronous work
-  /// that operates on behalf of the synchronous function that calls it.
-  /// Like `Task.detached(priority:operation:)`,
-  /// this function creates a separate, top-level task.
-  /// Unlike `Task.detached(priority:operation:)`,
-  /// the task created by `Task.init(priority:operation:)`
-  /// inherits the priority and actor context of the caller,
-  /// so the operation is treated more like an asynchronous extension
-  /// to the synchronous operation.
-  ///
-  /// You need to keep a reference to the task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - priority: The priority of the task.
-  ///     Pass `nil` to use the priority from `Task.currentPriority`.
-  ///   - operation: The operation to perform.
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public init(
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping @isolated(any) () async -> Success
-  ) {
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: true,
-      inheritContext: true, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-    // Create the asynchronous task.
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    let (task, _) = Builtin.createTask(flags: flags,
-                                       initialSerialExecutor: builtinSerialExecutor,
-                                       operation: operation)
-
-    self._task = task
-  }
-#endif
-}
-
-@available(SwiftStdlib 6.2, *)
-extension Task where Failure == Never {
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-  public init(
-    name: String?,
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping @isolated(any) () async -> Success
-  ) {
-    fatalError("Unavailable in task-to-thread concurrency model.")
-  }
-#elseif $Embedded
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(SwiftStdlib 6.2, *)
-  public init(
-    name: String?,
-    // TaskExecutor is unavailable in embedded
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping () async -> Success
-  ) {
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: false,
-      copyTaskLocals: true,
-      inheritContext: true,
-      enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false,
-      isSynchronousStart: false)
-
-    // Create the asynchronous task.
-    let (task, _) = Builtin.createAsyncTask(flags, operation)
-
-    self._task = task
-  }
-#else
-  /// Runs the given nonthrowing operation asynchronously
-  /// as part of a new top-level task on behalf of the current actor.
-  ///
-  /// Use this function when creating asynchronous work
-  /// that operates on behalf of the synchronous function that calls it.
-  /// Like `Task.detached(priority:operation:)`,
-  /// this function creates a separate, top-level task.
-  /// Unlike `Task.detached(priority:operation:)`,
-  /// the task created by `Task.init(priority:operation:)`
-  /// inherits the priority and actor context of the caller,
-  /// so the operation is treated more like an asynchronous extension
-  /// to the synchronous operation.
-  ///
-  /// You need to keep a reference to the task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - name: The high-level human-readable name given for this task
-  ///   - priority: The priority of the task.
-  ///     Pass `nil` to use the priority from `Task.currentPriority`.
-  ///   - operation: The operation to perform.
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(SwiftStdlib 6.2, *)
-  public init(
-    name: String?,
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping @isolated(any) () async -> Success
-  ) {
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: true,
-      inheritContext: true, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-    // Create the asynchronous task.
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    var task: Builtin.NativeObject?
-    #if $BuiltinCreateAsyncTaskName
-    if let name {
-      task =
-        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
-          Builtin.createTask(
-            flags: flags,
-            initialSerialExecutor: builtinSerialExecutor,
-            taskName: nameBytes.baseAddress!._rawValue,
-            operation: operation).0
-      }
-    }
-    #endif
-    if task == nil {
-      // either no task name was set, or names are unsupported
-      task = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      operation: operation).0
-    }
-
-    self._task = task!
-  }
-#endif
-}
-
-@available(SwiftStdlib 5.1, *)
-extension Task where Failure == Error {
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-  public init(
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping @isolated(any) () async throws -> Success
-  ) {
-    fatalError("Unavailable in task-to-thread concurrency model")
-  }
-#else
-  /// Runs the given throwing operation asynchronously
-  /// as part of a new top-level task on behalf of the current actor.
-  ///
-  /// Use this function when creating asynchronous work
-  /// that operates on behalf of the synchronous function that calls it.
-  /// Like `Task.detached(priority:operation:)`,
-  /// this function creates a separate, top-level task.
-  /// Unlike `detach(priority:operation:)`,
-  /// the task created by `Task.init(priority:operation:)`
-  /// inherits the priority and actor context of the caller,
-  /// so the operation is treated more like an asynchronous extension
-  /// to the synchronous operation.
-  ///
-  /// You need to keep a reference to the task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - priority: The priority of the task.
-  ///     Pass `nil` to use the priority from `Task.currentPriority`.
-  ///   - operation: The operation to perform.
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public init(
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping @isolated(any) () async throws -> Success
-  ) {
-    // Set up the task flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: true,
-      inheritContext: true, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-    // Create the asynchronous task future.
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    let (task, _) = Builtin.createTask(flags: flags,
-                                       initialSerialExecutor:
-                                         builtinSerialExecutor,
-                                       operation: operation)
-
-    self._task = task
-  }
-#endif
-}
-
-
-@available(SwiftStdlib 6.2, *)
-extension Task where Failure == Error {
-  #if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-  public init(
-    name: String?,
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping @isolated(any) () async throws -> Success
-) {
-  fatalError("Unavailable in task-to-thread concurrency model.")
-}
-  #elseif $Embedded
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(SwiftStdlib 6.2, *)
-  public init(
-    name: String?,
-    // TaskExecutor is unavailable in embedded
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping () async throws -> Success
-) {
-  // Set up the job flags for a new task.
-  let flags = taskCreateFlags(
-    priority: priority, isChildTask: false, copyTaskLocals: true,
-    inheritContext: true, enqueueJob: true,
-    addPendingGroupTaskUnconditionally: false,
-    isDiscardingTask: false, isSynchronousStart: false)
-
-  // Create the asynchronous task.
-  let (task, _) = Builtin.createAsyncTask(flags, operation)
-
-self._task = task
-}
-  #else
-  /// Runs the given nonthrowing operation asynchronously
-  /// as part of a new top-level task on behalf of the current actor.
-  ///
-  /// Use this function when creating asynchronous work
-  /// that operates on behalf of the synchronous function that calls it.
-  /// Like `Task.detached(priority:operation:)`,
-  /// this function creates a separate, top-level task.
-  /// Unlike `Task.detached(priority:operation:)`,
-  /// the task created by `Task.init(priority:operation:)`
-  /// inherits the priority and actor context of the caller,
-  /// so the operation is treated more like an asynchronous extension
-  /// to the synchronous operation.
-  ///
-  /// You need to keep a reference to the task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - name: The high-level human-readable name given for this task
-  ///   - priority: The priority of the task.
-  ///     Pass `nil` to use the priority from `Task.currentPriority`.
-  ///   - operation: The operation to perform.
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(SwiftStdlib 6.2, *)
-  public init(
-    name: String?,
-    priority: TaskPriority? = nil,
-    @_inheritActorContext @_implicitSelfCapture operation: sending @escaping @isolated(any) () async throws -> Success
-) {
-  // Set up the job flags for a new task.
-  let flags = taskCreateFlags(
-    priority: priority, isChildTask: false, copyTaskLocals: true,
-    inheritContext: true, enqueueJob: true,
-    addPendingGroupTaskUnconditionally: false,
-    isDiscardingTask: false, isSynchronousStart: false)
-
-  // Create the asynchronous task.
-  let builtinSerialExecutor =
-    unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-  var task: Builtin.NativeObject?
-  #if $BuiltinCreateAsyncTaskName
-  if let name {
-    task =
-      unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
-        Builtin.createTask(
-          flags: flags,
-          initialSerialExecutor: builtinSerialExecutor,
-          taskName: nameBytes.baseAddress!._rawValue,
-          operation: operation).0
-      }
-  }
-  #endif
-  if task == nil {
-    // either no task name was set, or names are unsupported
-    task = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      operation: operation).0
-  }
-
-  self._task = task!
-  }
-  #endif
-}
-
-// ==== Detached Tasks ---------------------------------------------------------
-
-@available(SwiftStdlib 5.1, *)
-extension Task where Failure == Never {
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-  public static func detached(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async -> Success
-  ) -> Task<Success, Failure> {
-    fatalError("Unavailable in task-to-thread concurrency model")
-  }
-#else
-  /// Runs the given nonthrowing operation asynchronously
-  /// as part of a new top-level task.
-  ///
-  /// Don't use a detached task if it's possible
-  /// to model the operation using structured concurrency features like child tasks.
-  /// Child tasks inherit the parent task's priority and task-local storage,
-  /// and canceling a parent task automatically cancels all of its child tasks.
-  /// You need to handle these considerations manually with a detached task.
-  ///
-  /// You need to keep a reference to the detached task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - priority: The priority of the task.
-  ///   - operation: The operation to perform.
-  ///
-  /// - Returns: A reference to the task.
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public static func detached(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async -> Success
-  ) -> Task<Success, Failure> {
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: false,
-      inheritContext: false, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-    // Create the asynchronous task future.
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    let (task, _) = Builtin.createTask(flags: flags,
-                                       initialSerialExecutor:
-                                         builtinSerialExecutor,
-                                       operation: operation)
-
-    return Task(task)
-  }
-#endif
-}
-
-@available(SwiftStdlib 6.2, *)
-extension Task where Failure == Never {
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-  public static func detached(
-    name: String?,
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async -> Success
-  ) -> Task<Success, Failure> {
-    fatalError("Unavailable in task-to-thread concurrency model")
-  }
-#else
-  /// Runs the given nonthrowing operation asynchronously
-  /// as part of a new top-level task.
-  ///
-  /// Don't use a detached task if it's possible
-  /// to model the operation using structured concurrency features like child tasks.
-  /// Child tasks inherit the parent task's priority and task-local storage,
-  /// and canceling a parent task automatically cancels all of its child tasks.
-  /// You need to handle these considerations manually with a detached task.
-  ///
-  /// You need to keep a reference to the detached task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - name: Human readable name of the task.
-  ///   - priority: The priority of the task.
-  ///   - operation: The operation to perform.
-  ///
-  /// - Returns: A reference to the task.
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public static func detached(
-    name: String?,
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async -> Success
-  ) -> Task<Success, Failure> {
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: false,
-      inheritContext: false, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-    // Create the asynchronous task.
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    var task: Builtin.NativeObject?
-    #if $BuiltinCreateAsyncTaskName
-    if let name {
-      task =
-        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
-          Builtin.createTask(
-            flags: flags,
-            initialSerialExecutor: builtinSerialExecutor,
-            taskName: nameBytes.baseAddress!._rawValue,
-            operation: operation).0
-        }
-    }
-    #endif
-    if task == nil {
-      // either no task name was set, or names are unsupported
-      task = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      operation: operation).0
-    }
-
-    return Task(task!)
-  }
-#endif
-}
-
-@available(SwiftStdlib 5.1, *)
-extension Task where Failure == Error {
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-  public static func detached(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async throws -> Success
-  ) -> Task<Success, Failure> {
-    fatalError("Unavailable in task-to-thread concurrency model")
-  }
-#else
-  /// Runs the given throwing operation asynchronously
-  /// as part of a new top-level task.
-  ///
-  /// If the operation throws an error, this method propagates that error.
-  ///
-  /// Don't use a detached task if it's possible
-  /// to model the operation using structured concurrency features like child tasks.
-  /// Child tasks inherit the parent task's priority and task-local storage,
-  /// and canceling a parent task automatically cancels all of its child tasks.
-  /// You need to handle these considerations manually with a detached task.
-  ///
-  /// You need to keep a reference to the detached task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - priority: The priority of the task.
-  ///   - operation: The operation to perform.
-  ///
-  /// - Returns: A reference to the task.
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public static func detached(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async throws -> Success
-  ) -> Task<Success, Failure> {
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: false,
-      inheritContext: false, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-    // Create the asynchronous task future.
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    let (task, _) = Builtin.createTask(flags: flags,
-                                       initialSerialExecutor:
-                                         builtinSerialExecutor,
-                                       operation: operation)
-
-    return Task(task)
-  }
-#endif
-}
-
-@available(SwiftStdlib 6.2, *)
-extension Task where Failure == Error {
-#if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-  @discardableResult
-  @_alwaysEmitIntoClient
-  @available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
-  public static func detached(
-    name: String?,
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async throws -> Success
-  ) -> Task<Success, Failure> {
-    fatalError("Unavailable in task-to-thread concurrency model")
-  }
-#else
-  /// Runs the given throwing operation asynchronously
-  /// as part of a new top-level task.
-  ///
-  /// If the operation throws an error, this method propagates that error.
-  ///
-  /// Don't use a detached task if it's possible
-  /// to model the operation using structured concurrency features like child tasks.
-  /// Child tasks inherit the parent task's priority and task-local storage,
-  /// and canceling a parent task automatically cancels all of its child tasks.
-  /// You need to handle these considerations manually with a detached task.
-  ///
-  /// You need to keep a reference to the detached task
-  /// if you want to cancel it by calling the `Task.cancel()` method.
-  /// Discarding your reference to a detached task
-  /// doesn't implicitly cancel that task,
-  /// it only makes it impossible for you to explicitly cancel the task.
-  ///
-  /// - Parameters:
-  ///   - priority: The priority of the task.
-  ///   - operation: The operation to perform.
-  ///
-  /// - Returns: A reference to the task.
-  @discardableResult
-  @_alwaysEmitIntoClient
-  public static func detached(
-    name: String?,
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async throws -> Success
-  ) -> Task<Success, Failure> {
-    // Set up the job flags for a new task.
-    let flags = taskCreateFlags(
-      priority: priority, isChildTask: false, copyTaskLocals: false,
-      inheritContext: false, enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: false, isSynchronousStart: false)
-
-    // Create the asynchronous task future.
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    var task: Builtin.NativeObject?
-    #if $BuiltinCreateAsyncTaskName
-    if let name {
-      task =
-        unsafe name.utf8CString.withUnsafeBufferPointer { nameBytes in
-          Builtin.createTask(
-            flags: flags,
-            initialSerialExecutor: builtinSerialExecutor,
-            taskName: nameBytes.baseAddress!._rawValue,
-            operation: operation).0
-        }
-    }
-    #endif
-    if task == nil {
-      // either no task name was set, or names are unsupported
-      task = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      operation: operation).0
-    }
-
-    return Task(task!)
-  }
-#endif
-}
-
 // ==== Task Name --------------------------------------------------------------
 
 @available(SwiftStdlib 6.2, *)
@@ -1225,6 +600,13 @@ extension Task where Success == Never, Failure == Never {
   ///         }
   ///       }
   ///     }
+  ///
+  /// ### Task name availability
+  /// The task name is only available when running with a recent runtime (Swift 6.2+).
+  ///
+  /// ``Task`` initializers which may accept a task name are more available than this property,
+  /// for convenience purposes, in order to not have to set task names conditionally
+  /// however their effect is runtime dependent, and is reflected in the availability of this property.
   @available(SwiftStdlib 6.2, *)
   public static var name: String? {
     return _getCurrentTaskNameString()
@@ -1255,12 +637,12 @@ extension Task where Success == Never, Failure == Never {
           continuation: continuation)
 
       #if !$Embedded && !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-      if #available(SwiftStdlib 6.2, *) {
+      if #available(StdlibDeploymentTarget 6.2, *) {
         let executor = Task.currentExecutor
 
         executor.enqueue(ExecutorJob(context: job))
       } else {
-        _enqueueJobGlobal(job)
+        fatalError("we shouldn't get here; if we have, availability is broken")
       }
       #else
       _enqueueJobGlobal(job)
@@ -1302,7 +684,7 @@ extension Task where Success == Never, Failure == Never {
 @available(SwiftStdlib 5.1, *)
 public func withUnsafeCurrentTask<T>(body: (UnsafeCurrentTask?) throws -> T) rethrows -> T {
   guard let _task = _getCurrentAsyncTask() else {
-    return try unsafe body(nil)
+    return try body(nil)
   }
 
   // FIXME: This retain seems pretty wrong, however if we don't we WILL crash
@@ -1316,7 +698,7 @@ public func withUnsafeCurrentTask<T>(body: (UnsafeCurrentTask?) throws -> T) ret
 @available(SwiftStdlib 6.0, *)
 public func withUnsafeCurrentTask<T>(body: (UnsafeCurrentTask?) async throws -> T) async rethrows -> T {
   guard let _task = _getCurrentAsyncTask() else {
-    return try unsafe await body(nil)
+    return try await body(nil)
   }
 
   // FIXME: This retain seems pretty wrong, however if we don't we WILL crash
@@ -1440,7 +822,7 @@ func _enqueueJobGlobalWithDelay(_ delay: UInt64, _ task: UnownedJob) {
   return _enqueueJobGlobalWithDelay(delay, task._context)
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_silgen_name("swift_task_enqueueGlobalWithDeadline")
 @usableFromInline
 func _enqueueJobGlobalWithDeadline(_ seconds: Int64, _ nanoseconds: Int64,
@@ -1516,10 +898,10 @@ internal func _runAsyncMain(_ asyncFun: @Sendable @escaping () async throws -> (
   }
 
   let job = Builtin.convertTaskToJob(theTask)
-  if #available(SwiftStdlib 6.2, *) {
+  if #available(StdlibDeploymentTarget 6.2, *) {
     MainActor.executor.enqueue(ExecutorJob(context: job))
   } else {
-    Builtin.unreachable()
+    fatalError("we shouldn't get here; if we have, availability is broken")
   }
 
   _asyncMainDrainQueue()
diff --git a/stdlib/public/Concurrency/TaskCancellation.swift b/stdlib/public/Concurrency/TaskCancellation.swift
index 62ce412e60798..3dbcba0371685 100644
--- a/stdlib/public/Concurrency/TaskCancellation.swift
+++ b/stdlib/public/Concurrency/TaskCancellation.swift
@@ -39,13 +39,13 @@ import Swift
 /// ### Execution order and semantics
 /// The `operation` closure is always invoked, even when the
 /// `withTaskCancellationHandler(operation:onCancel:)` method is called from a task
-/// that was already cancelled.
+/// that was already canceled.
 ///
 /// When `withTaskCancellationHandler(operation:onCancel:)` is used in a task that has already been
-/// cancelled, the cancellation handler will be executed
+/// canceled, the cancellation handler will be executed
 /// immediately before the `operation` closure gets to execute.
 ///
-/// This allows the cancellation handler to set some external "cancelled" flag
+/// This allows the cancellation handler to set some external "canceled" flag
 /// that the operation may be *atomically* checking for in order to avoid
 /// performing any actual work once the operation gets to run.
 ///
diff --git a/stdlib/public/Concurrency/TaskGroup+Embedded.swift b/stdlib/public/Concurrency/TaskGroup+Embedded.swift
deleted file mode 100644
index 7aed41f538eb5..0000000000000
--- a/stdlib/public/Concurrency/TaskGroup+Embedded.swift
+++ /dev/null
@@ -1,283 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2025 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import Swift
-
-// FIXME: This is a workaround for trouble including gyb-generated sources
-
-#if SWIFT_CONCURRENCY_EMBEDDED
-
-@available(SwiftStdlib 5.1, *)
-extension TaskGroup {
-
-  @available(SwiftStdlib 5.1, *)
-  @_alwaysEmitIntoClient
-  public mutating func addTask(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async -> ChildTaskResult
-  ) {
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: true,
-      copyTaskLocals: false,
-      inheritContext: false,
-      enqueueJob: true,
-      addPendingGroupTaskUnconditionally: true,
-      isDiscardingTask: false,
-      isSynchronousStart: false
-    )
-
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    _ = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      taskGroup: _group,
-      operation: operation).0
-  }
-
-  @available(SwiftStdlib 5.1, *)
-  @_alwaysEmitIntoClient
-  public mutating func addTaskUnlessCancelled(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async -> ChildTaskResult
-  ) -> Bool {
-    let canAdd = _taskGroupAddPendingTask(group: _group, unconditionally: false)
-
-    guard canAdd else {
-      return false
-    }
-
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: true,
-      copyTaskLocals: false,
-      inheritContext: false,
-      enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: true,
-      isSynchronousStart: false
-    )
-
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    _ = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      taskGroup: _group,
-      operation: operation).0
-
-    return true
-  }
-}
-
-@available(SwiftStdlib 5.1, *)
-extension ThrowingTaskGroup {
-
-  @available(SwiftStdlib 5.1, *)
-  @_alwaysEmitIntoClient
-  public mutating func addTask(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async throws -> ChildTaskResult
-  ) {
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: true,
-      copyTaskLocals: false,
-      inheritContext: false,
-      enqueueJob: true,
-      addPendingGroupTaskUnconditionally: true,
-      isDiscardingTask: false,
-      isSynchronousStart: false
-    )
-
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    _ = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      taskGroup: _group,
-      operation: operation).0
-  }
-
-  @available(SwiftStdlib 5.1, *)
-  @_alwaysEmitIntoClient
-  public mutating func addTaskUnlessCancelled(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async throws -> ChildTaskResult
-  ) -> Bool {
-    let canAdd = _taskGroupAddPendingTask(group: _group, unconditionally: false)
-
-    guard canAdd else {
-      return false
-    }
-
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: true,
-      copyTaskLocals: false,
-      inheritContext: false,
-      enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: true,
-      isSynchronousStart: false
-    )
-
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    _ = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      taskGroup: _group,
-      operation: operation).0
-
-    return true
-  }
-}
-
-@available(SwiftStdlib 5.9, *)
-extension DiscardingTaskGroup {
-
-  @available(SwiftStdlib 5.9, *)
-  @_alwaysEmitIntoClient
-  public mutating func addTask(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async -> Void
-  ) {
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: true,
-      copyTaskLocals: false,
-      inheritContext: false,
-      enqueueJob: true,
-      addPendingGroupTaskUnconditionally: true,
-      isDiscardingTask: true,
-      isSynchronousStart: false
-    )
-
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    _ = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      taskGroup: _group,
-      operation: operation).0
-  }
-
-  @available(SwiftStdlib 5.9, *)
-  @_alwaysEmitIntoClient
-  public mutating func addTaskUnlessCancelled(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async -> Void
-  ) -> Bool {
-    let canAdd = _taskGroupAddPendingTask(group: _group, unconditionally: false)
-
-    guard canAdd else {
-      return false
-    }
-
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: true,
-      copyTaskLocals: false,
-      inheritContext: false,
-      enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: true,
-      isSynchronousStart: false
-    )
-
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    _ = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      taskGroup: _group,
-      operation: operation).0
-
-    return true
-  }
-}
-
-@available(SwiftStdlib 5.9, *)
-extension ThrowingDiscardingTaskGroup {
-
-  @available(SwiftStdlib 5.9, *)
-  @_alwaysEmitIntoClient
-  public mutating func addTask(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async throws -> Void
-  ) {
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: true,
-      copyTaskLocals: false,
-      inheritContext: false,
-      enqueueJob: true,
-      addPendingGroupTaskUnconditionally: true,
-      isDiscardingTask: true,
-      isSynchronousStart: false
-    )
-
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-  
-    _ = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      taskGroup: _group,
-      operation: operation).0
-  }
-
-  @available(SwiftStdlib 5.9, *)
-  @_alwaysEmitIntoClient
-  public mutating func addTaskUnlessCancelled(
-    priority: TaskPriority? = nil,
-    operation: sending @escaping @isolated(any) () async throws -> Void
-  ) -> Bool {
-    let canAdd = _taskGroupAddPendingTask(group: _group, unconditionally: false)
-
-    guard canAdd else {
-      return false
-    }
-
-    let flags = taskCreateFlags(
-      priority: priority,
-      isChildTask: true,
-      copyTaskLocals: false,
-      inheritContext: false,
-      enqueueJob: true,
-      addPendingGroupTaskUnconditionally: false,
-      isDiscardingTask: true,
-      isSynchronousStart: false
-    )
-
-    let builtinSerialExecutor =
-      unsafe Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-
-    _ = Builtin.createTask(
-      flags: flags,
-      initialSerialExecutor: builtinSerialExecutor,
-      taskGroup: _group,
-      operation: operation).0
-
-    return true
-  }
-}
-
-#endif
diff --git a/stdlib/public/Concurrency/TaskGroup+addTask.swift.gyb b/stdlib/public/Concurrency/TaskGroup+addTask.swift.gyb
index 298faf73dacb8..d4afec2e1eafe 100644
--- a/stdlib/public/Concurrency/TaskGroup+addTask.swift.gyb
+++ b/stdlib/public/Concurrency/TaskGroup+addTask.swift.gyb
@@ -31,7 +31,7 @@ import Swift
 %          'ThrowingDiscardingTaskGroup'
 %        ],
 %        [
-%          '@available(SwiftStdlib 6.2, *)',
+%          '@available(SwiftStdlib 6.0, *)', # because task executor
 %          '@_unavailableInEmbedded', # since TaskExecutor is not available on embedded
 %        ],
 %        ['addTask', 'addTaskUnlessCancelled'],
@@ -43,6 +43,42 @@ import Swift
 %          'operation: sending @escaping @isolated(any) () async throws -> ChildTaskResult'
 %        ],
 %      ),
+%      (
+%        '', # no #if condition
+%        [
+%          'TaskGroup',
+%          'ThrowingTaskGroup',
+%        ],
+%        [
+%          '@available(SwiftStdlib 5.1, *)',
+%        ],
+%        ['addTask', 'addTaskUnlessCancelled'],
+%        [
+%          'name: String?',
+%          # without task executor
+%          'priority: TaskPriority? = nil',
+%          # throws and ChildTaskResult will be adjusted per task group type
+%          'operation: sending @escaping @isolated(any) () async throws -> ChildTaskResult'
+%        ],
+%      ),
+%      (
+%        '', # no #if condition
+%        [
+%          'DiscardingTaskGroup',
+%          'ThrowingDiscardingTaskGroup'
+%        ],
+%        [
+%          '@available(SwiftStdlib 5.9, *)', # because Discarding task groups
+%        ],
+%        ['addTask', 'addTaskUnlessCancelled'],
+%        [
+%          'name: String?',
+%          # without task executor
+%          'priority: TaskPriority? = nil',
+%          # throws and ChildTaskResult will be adjusted per task group type
+%          'operation: sending @escaping @isolated(any) () async throws -> ChildTaskResult'
+%        ],
+%      ),
 %      # -----------------------------------------------------------------------
 %      # === Added TaskExecutor
 %      (
@@ -170,7 +206,9 @@ import Swift
 #if ${IFDEF}
 % end
 
-% if IS_DISCARDING:
+% if HAS_TASK_EXECUTOR:
+@available(SwiftStdlib 6.0, *)
+% elif IS_DISCARDING:
 @available(SwiftStdlib 5.9, *)
 % else:
 @available(SwiftStdlib 5.1, *)
@@ -194,7 +232,6 @@ extension ${TYPE} {
   ///   - name: Human readable name of this task.
   % end
   % if HAS_TASK_EXECUTOR:
-  ///   - taskExecutor:
   ///   - taskExecutor: The task executor that the child task should be started on and keep using.
   ///      Explicitly passing `nil` as the executor preference is equivalent to
   ///      calling the `${METHOD_NAME}` method without a preference, and effectively
@@ -205,8 +242,6 @@ extension ${TYPE} {
   ///   - priority: The priority of the operation task.
   ///     Omit this parameter or pass `nil` to inherit the task group's base priority.
   % end
-  ///     Omit this parameter or pass `.unspecified`
-  ///     to set the child task's priority to the priority of the group.
   ///   - operation: The operation to execute as part of the task group.
   % if IS_ADD_UNLESS_CANCELLED:
   /// - Returns: `true` if the child task was added to the group;
@@ -267,7 +302,9 @@ extension ${TYPE} {
             flags: flags,
             initialSerialExecutor: builtinSerialExecutor,
             taskGroup: _group,
+            % if HAS_TASK_EXECUTOR:
             initialTaskExecutorConsuming: taskExecutor,
+            % end
             taskName: nameBytes.baseAddress!._rawValue,
             operation: operation).0
         }
@@ -275,8 +312,8 @@ extension ${TYPE} {
     #endif // $BuiltinCreateAsyncTaskName
     % end # HAS_TASK_NAME
 
-    // Task name was not set, or task name createTask is unavailable
     % if HAS_TASK_EXECUTOR:
+    // Task name was not set, or task name createTask is unavailable
     if task == nil, let taskExecutor {
       #if $BuiltinCreateAsyncTaskOwnedTaskExecutor
       task = ${TASK_CREATE_FN}(
diff --git a/stdlib/public/Concurrency/TaskGroup.cpp b/stdlib/public/Concurrency/TaskGroup.cpp
index 6de5d06c8e347..0d1d2be13d156 100644
--- a/stdlib/public/Concurrency/TaskGroup.cpp
+++ b/stdlib/public/Concurrency/TaskGroup.cpp
@@ -27,13 +27,13 @@
 #include "swift/ABI/Task.h"
 #include "swift/ABI/TaskGroup.h"
 #include "swift/ABI/TaskOptions.h"
+#include "swift/Basic/Casting.h"
 #include "swift/Basic/RelativePointer.h"
 #include "swift/Basic/STLExtras.h"
 #include "swift/Runtime/Concurrency.h"
 #include "swift/Runtime/Config.h"
 #include "swift/Runtime/Heap.h"
 #include "swift/Runtime/HeapObject.h"
-#include "swift/Runtime/STLCompatibility.h"
 #include "swift/Threading/Mutex.h"
 #include <atomic>
 #include <deque>
@@ -439,12 +439,12 @@ class TaskGroupBase : public TaskGroupTaskStatusRecord {
   /// by simultaneously decrementing one Pending and one Waiting tasks.
   ///
   /// This is used to atomically perform a waiting task completion.
-  /// The change is made 'relaxed' and may have to be retried.
+  /// The change is made with relaxed memory ordering.
   ///
   /// This can be safely used in a discarding task group as well,
   /// where the "ready" change will simply be ignored, since there
   /// are no ready bits to change.
-  bool statusCompletePendingReadyWaiting(TaskGroupStatus &old);
+  void statusCompletePendingReadyWaiting(TaskGroupStatus &old);
 
   /// Cancel the task group and all tasks within it.
   ///
@@ -568,7 +568,11 @@ struct TaskGroupStatus {
     // so if we're in "discard results" mode, we must not decrement the ready count,
     // as there is no ready count in the status.
     change += group->isAccumulatingResults() ? oneReadyTask : 0;
-    return TaskGroupStatus{status - change};
+
+    TaskGroupStatus newStatus{status - change};
+    SWIFT_TASK_GROUP_DEBUG_LOG(group, "completingPendingReadyWaiting %s",
+                               newStatus.to_string(group).c_str());
+    return newStatus;
   }
 
   TaskGroupStatus completingPendingReady(const TaskGroupBase* _Nonnull group) {
@@ -669,11 +673,12 @@ struct TaskGroupStatus {
   };
 };
 
-bool TaskGroupBase::statusCompletePendingReadyWaiting(TaskGroupStatus &old) {
-  return status.compare_exchange_strong(
+void TaskGroupBase::statusCompletePendingReadyWaiting(TaskGroupStatus &old) {
+  while (!status.compare_exchange_weak(
       old.status, old.completingPendingReadyWaiting(this).status,
       /*success*/ std::memory_order_relaxed,
-      /*failure*/ std::memory_order_relaxed);
+      /*failure*/ std::memory_order_relaxed)) {
+  } // Loop until the compare_exchange succeeds
 }
 
 AsyncTask *TaskGroupBase::claimWaitingTask() {
@@ -681,12 +686,11 @@ AsyncTask *TaskGroupBase::claimWaitingTask() {
          "attempted to claim waiting task but status indicates no waiting "
          "task is present!");
 
-  auto waitingTask = waitQueue.load(std::memory_order_acquire);
-  if (!waitQueue.compare_exchange_strong(waitingTask, nullptr,
-                                         std::memory_order_release,
-                                         std::memory_order_relaxed)) {
-    swift_Concurrency_fatalError(0, "Failed to claim waitingTask!");
-  }
+  auto waitingTask = waitQueue.exchange(nullptr, std::memory_order_acquire);
+  SWIFT_TASK_GROUP_DEBUG_LOG(this, "claimed waiting task %p", waitingTask);
+  if (!waitingTask)
+    swift_Concurrency_fatalError(0, "Claimed NULL waitingTask!");
+
   return waitingTask;
 }
 void TaskGroupBase::runWaitingTask(PreparedWaitingTask prepared) {
@@ -737,13 +741,19 @@ uint64_t TaskGroupBase::pendingTasks() const {
 
 TaskGroupStatus TaskGroupBase::statusMarkWaitingAssumeAcquire() {
   auto old = status.fetch_or(TaskGroupStatus::waiting, std::memory_order_acquire);
-  return TaskGroupStatus{old | TaskGroupStatus::waiting};
+  TaskGroupStatus newStatus{old | TaskGroupStatus::waiting};
+  SWIFT_TASK_GROUP_DEBUG_LOG(this, "statusMarkWaitingAssumeAcquire %s",
+                             newStatus.to_string(this).c_str());
+  return newStatus;
 }
 
 TaskGroupStatus TaskGroupBase::statusMarkWaitingAssumeRelease() {
   auto old = status.fetch_or(TaskGroupStatus::waiting,
                              std::memory_order_release);
-  return TaskGroupStatus{old | TaskGroupStatus::waiting};
+  TaskGroupStatus newStatus{old | TaskGroupStatus::waiting};
+  SWIFT_TASK_GROUP_DEBUG_LOG(this, "statusMarkWaitingAssumeRelease %s",
+                             newStatus.to_string(this).c_str());
+  return newStatus;
 }
 
 /// Add a single pending task to the status counter.
@@ -786,6 +796,8 @@ TaskGroupStatus TaskGroupBase::statusAddPendingTaskAssumeRelaxed(bool unconditio
 TaskGroupStatus TaskGroupBase::statusRemoveWaitingRelease() {
   auto old = status.fetch_and(~TaskGroupStatus::waiting,
                               std::memory_order_release);
+  SWIFT_TASK_GROUP_DEBUG_LOG(this, "statusRemoveWaitingRelease %s",
+                             old.to_string(this).c_str());
   return TaskGroupStatus{old};
 }
 
@@ -793,6 +805,9 @@ bool TaskGroupBase::statusCancel() {
   /// The cancelled bit is always the same, the first one, between all task group implementations:
   const uint64_t cancelled = TaskGroupStatus::cancelled;
   auto old = status.fetch_or(cancelled, std::memory_order_relaxed);
+  SWIFT_TASK_GROUP_DEBUG_LOG(
+      this, "statusCancel %s",
+      TaskGroupStatus{old | cancelled}.to_string(this).c_str());
 
   // return if the status was already cancelled before we flipped it or not
   return old & cancelled;
@@ -827,6 +842,8 @@ class AccumulatingTaskGroup: public TaskGroupBase {
     auto old = status.fetch_add(TaskGroupStatus::oneReadyTask,
                                 std::memory_order_acquire);
     auto s = TaskGroupStatus{old + TaskGroupStatus::oneReadyTask};
+    SWIFT_TASK_GROUP_DEBUG_LOG(this, "statusMarkWaitingAssumeRelease %s",
+                               s.to_string(this).c_str());
     assert(s.readyTasks(this) <= s.pendingTasks(this));
     return s;
   }
@@ -880,23 +897,17 @@ class DiscardingTaskGroup: public TaskGroupBase {
     return TaskGroupStatus{status.load(std::memory_order_acquire)};
   }
 
-  /// Compare-and-set old status to a status derived from the old one,
-  /// by simultaneously decrementing one Pending and one Waiting tasks.
-  ///
-  /// This is used to atomically perform a waiting task completion.
-  bool statusCompletePendingReadyWaiting(TaskGroupStatus &old) {
-    return status.compare_exchange_strong(
-      old.status, old.completingPendingReadyWaiting(this).status,
-      /*success*/ std::memory_order_relaxed,
-      /*failure*/ std::memory_order_relaxed);
-  }
-
   /// Decrement the pending status count.
   /// Returns the *assumed* new status, including the just performed -1.
   TaskGroupStatus statusCompletePendingAssumeRelease() {
     auto old = status.fetch_sub(TaskGroupStatus::onePendingTask,
                                 std::memory_order_release);
     assert(TaskGroupStatus{old}.pendingTasks(this) > 0 && "attempted to decrement pending count when it was 0 already");
+    SWIFT_TASK_GROUP_DEBUG_LOG(
+        this, "statusComplete = %s",
+        TaskGroupStatus{status.load(std::memory_order_relaxed)}
+            .to_string(this)
+            .c_str());
     return TaskGroupStatus{old - TaskGroupStatus::onePendingTask};
   }
 
@@ -1166,6 +1177,10 @@ bool TaskGroup::isCancelled() {
   return asBaseImpl(this)->isCancelled();
 }
 
+bool TaskGroup::statusCancel() {
+  return asBaseImpl(this)->statusCancel();
+}
+
 // =============================================================================
 // ==== offer ------------------------------------------------------------------
 
@@ -1319,6 +1334,8 @@ void AccumulatingTaskGroup::offer(AsyncTask *completedTask, AsyncContext *contex
   // ==== a) has waiting task, so let us complete it right away
   if (assumed.hasWaitingTask()) {
     auto waitingTask = claimWaitingTask();
+    SWIFT_TASK_GROUP_DEBUG_LOG(this, "offer, waitingTask = %p", waitingTask);
+    assert(waitingTask);
     auto prepared = prepareWaitingTaskWithTask(
         /*complete=*/waitingTask, /*with=*/completedTask,
         assumed, hadErrorResult);
@@ -1476,14 +1493,7 @@ void DiscardingTaskGroup::offer(AsyncTask *completedTask, AsyncContext *context)
     // We grab the waiting task while holding the group lock, because this
     // allows a single task to get the waiting task and attempt to complete it.
     // As another offer gets to run, it will have either a different waiting task, or no waiting task at all.
-    auto waitingTask = waitQueue.load(std::memory_order_acquire);
-    if (!waitQueue.compare_exchange_strong(waitingTask, nullptr,
-                                           std::memory_order_release,
-                                           std::memory_order_relaxed)) {
-      swift_Concurrency_fatalError(0, "Failed to claim waitingTask!");
-    }
-    assert(waitingTask && "status claimed to have waitingTask but waitQueue was empty!");
-
+    auto waitingTask = claimWaitingTask();
     SWIFT_TASK_GROUP_DEBUG_LOG(this,
                                "offer, last pending task completed successfully, resume waitingTask:%p with completedTask:%p",
                                waitingTask, completedTask);
@@ -1554,8 +1564,11 @@ TaskGroupBase::PreparedWaitingTask TaskGroupBase::prepareWaitingTaskWithTask(
     bool hadErrorResult,
     bool alreadyDecremented,
     bool taskWasRetained) {
-  SWIFT_TASK_GROUP_DEBUG_LOG(this, "resume, waitingTask = %p, completedTask = %p, alreadyDecremented:%d, error:%d",
-                       waitingTask, alreadyDecremented, hadErrorResult, completedTask);
+  SWIFT_TASK_GROUP_DEBUG_LOG(this,
+                             "resume, waitingTask = %p, completedTask = %p, "
+                             "alreadyDecremented:%d, error:%d",
+                             waitingTask, completedTask, alreadyDecremented,
+                             hadErrorResult);
   assert(waitingTask && "waitingTask must not be null when attempting to resume it");
   assert(assumed.hasWaitingTask());
 #if SWIFT_CONCURRENCY_TASK_TO_THREAD_MODEL
@@ -1575,9 +1588,8 @@ TaskGroupBase::PreparedWaitingTask TaskGroupBase::prepareWaitingTaskWithTask(
         enqueueCompletedTask(completedTask, hadErrorResult);
         return {nullptr};
 #else /* SWIFT_CONCURRENCY_TASK_TO_THREAD_MODEL */
-        if (!alreadyDecremented) {
-          (void) statusCompletePendingReadyWaiting(assumed);
-        }
+        if (!alreadyDecremented)
+          statusCompletePendingReadyWaiting(assumed);
 
         // Populate the waiting task with value from completedTask.
         auto result = PollResult::get(completedTask, hadErrorResult);
@@ -1639,9 +1651,8 @@ DiscardingTaskGroup::prepareWaitingTaskWithError(AsyncTask *waitingTask,
   _enqueueRawError(this, &readyQueue, error);
   return {nullptr};
 #else /* SWIFT_CONCURRENCY_TASK_TO_THREAD_MODEL */
-  if (!alreadyDecremented) {
+  if (!alreadyDecremented)
     statusCompletePendingReadyWaiting(assumed);
-  }
 
   // Run the task.
   auto result = PollResult::getError(error);
@@ -1661,7 +1672,7 @@ task_group_wait_resume_adapter(SWIFT_ASYNC_CONTEXT AsyncContext *_context) {
 
   auto context = static_cast<TaskFutureWaitAsyncContext *>(_context);
   auto resumeWithError =
-      std::bit_cast<AsyncVoidClosureResumeEntryPoint *>(context->ResumeParent);
+      function_cast<AsyncVoidClosureResumeEntryPoint *>(context->ResumeParent);
   return resumeWithError(context->Parent, context->errorResult);
 }
 
@@ -1713,7 +1724,7 @@ static void swift_taskGroup_wait_next_throwingImpl(
 
   auto context = static_cast<TaskFutureWaitAsyncContext *>(rawContext);
   context->ResumeParent =
-      std::bit_cast<TaskContinuationFunction *>(resumeFunction);
+      function_cast<TaskContinuationFunction *>(resumeFunction);
   context->Parent = callerContext;
   context->errorResult = nullptr;
   context->successResultPointer = resultPointer;
@@ -1792,77 +1803,81 @@ reevaluate_if_taskgroup_has_results:;
   auto waitHead = waitQueue.load(std::memory_order_acquire);
 
   // ==== 2) Ready task was polled, return with it immediately -----------------
-  if (assumed.readyTasks(this)) {
+  while (assumed.readyTasks(this)) {
+    // We loop when the compare_exchange fails.
     SWIFT_TASK_DEBUG_LOG("poll group = %p, tasks .ready = %d, .pending = %llu",
                          this, assumed.readyTasks(this), assumed.pendingTasks(this));
 
     auto assumedStatus = assumed.status;
     auto newStatus = TaskGroupStatus{assumedStatus};
-    if (status.compare_exchange_strong(
-        assumedStatus, newStatus.completingPendingReadyWaiting(this).status,
-        /*success*/ std::memory_order_release,
-        /*failure*/ std::memory_order_acquire)) {
-
-      // We're going back to running the task, so if we suspended before,
-      // we need to flag it as running again.
-      if (hasSuspended) {
-        waitingTask->flagAsRunning();
-      }
+    if (!status.compare_exchange_weak(
+            assumedStatus, newStatus.completingPendingReadyWaiting(this).status,
+            /*success*/ std::memory_order_release,
+            /*failure*/ std::memory_order_acquire)) {
+      assumed = TaskGroupStatus{assumedStatus};
+      continue; // We raced with something, try again.
+    }
+    SWIFT_TASK_DEBUG_LOG("poll, after CAS: %s", status.to_string().c_str());
 
-      // Success! We are allowed to poll.
-      ReadyQueueItem item;
-      bool taskDequeued = readyQueue.dequeue(item);
-      assert(taskDequeued); (void) taskDequeued;
-
-      auto futureFragment =
-          item.getStatus() == ReadyStatus::RawError ?
-          nullptr :
-          item.getTask()->futureFragment();
-
-      // Store the task in the result, so after we're done processing it may
-      // be swift_release'd; we kept it alive while it was in the readyQueue by
-      // an additional retain issued as we enqueued it there.
-
-      // Note that the task was detached from the task group when it
-      // completed, so we don't need to do that bit of record-keeping here.
-
-      switch (item.getStatus()) {
-        case ReadyStatus::Success:
-          // Immediately return the polled value
-          result.status = PollStatus::Success;
-          result.storage = futureFragment->getStoragePtr();
-          result.successType = futureFragment->getResultType();
-          result.retainedTask = item.getTask();
-          assert(result.retainedTask && "polled a task, it must be not null");
-          _swift_tsan_acquire(static_cast<Job *>(result.retainedTask));
-          unlock();
-          return result;
+    // We're going back to running the task, so if we suspended before,
+    // we need to flag it as running again.
+    if (hasSuspended) {
+      waitingTask->flagAsRunning();
+    }
 
-        case ReadyStatus::Error:
-          // Immediately return the polled value
-          result.status = PollStatus::Error;
-          result.storage =
-              reinterpret_cast<OpaqueValue *>(futureFragment->getError());
-          result.successType = ResultTypeInfo();
-          result.retainedTask = item.getTask();
-          assert(result.retainedTask && "polled a task, it must be not null");
-          _swift_tsan_acquire(static_cast<Job *>(result.retainedTask));
-          unlock();
-          return result;
+    // Success! We are allowed to poll.
+    ReadyQueueItem item;
+    bool taskDequeued = readyQueue.dequeue(item);
+    assert(taskDequeued); (void) taskDequeued;
+
+    auto futureFragment =
+        item.getStatus() == ReadyStatus::RawError ?
+        nullptr :
+        item.getTask()->futureFragment();
+
+    // Store the task in the result, so after we're done processing it may
+    // be swift_release'd; we kept it alive while it was in the readyQueue by
+    // an additional retain issued as we enqueued it there.
+
+    // Note that the task was detached from the task group when it
+    // completed, so we don't need to do that bit of record-keeping here.
+
+    switch (item.getStatus()) {
+      case ReadyStatus::Success:
+        // Immediately return the polled value
+        result.status = PollStatus::Success;
+        result.storage = futureFragment->getStoragePtr();
+        result.successType = futureFragment->getResultType();
+        result.retainedTask = item.getTask();
+        assert(result.retainedTask && "polled a task, it must be not null");
+        _swift_tsan_acquire(static_cast<Job *>(result.retainedTask));
+        unlock();
+        return result;
+
+      case ReadyStatus::Error:
+        // Immediately return the polled value
+        result.status = PollStatus::Error;
+        result.storage =
+            reinterpret_cast<OpaqueValue *>(futureFragment->getError());
+        result.successType = ResultTypeInfo();
+        result.retainedTask = item.getTask();
+        assert(result.retainedTask && "polled a task, it must be not null");
+        _swift_tsan_acquire(static_cast<Job *>(result.retainedTask));
+        unlock();
+        return result;
 
-        case ReadyStatus::Empty:
-          result.status = PollStatus::Empty;
-          result.storage = nullptr;
-          result.retainedTask = nullptr;
-          result.successType = this->successType;
-          unlock();
-          return result;
+      case ReadyStatus::Empty:
+        result.status = PollStatus::Empty;
+        result.storage = nullptr;
+        result.retainedTask = nullptr;
+        result.successType = this->successType;
+        unlock();
+        return result;
 
-        case ReadyStatus::RawError:
-          swift_Concurrency_fatalError(0, "accumulating task group should never use raw-errors!");
-      }
-      swift_Concurrency_fatalError(0, "must return result when status compare-and-swap was successful");
-    } // else, we failed status-cas (some other waiter claimed a ready pending task, try again)
+      case ReadyStatus::RawError:
+        swift_Concurrency_fatalError(0, "accumulating task group should never use raw-errors!");
+    }
+    swift_Concurrency_fatalError(0, "must return result when status compare-and-swap was successful");
   }
 
   // ==== 3) Add to wait queue -------------------------------------------------
@@ -1874,7 +1889,9 @@ reevaluate_if_taskgroup_has_results:;
   }
   while (true) {
     // Put the waiting task at the beginning of the wait queue.
-    SWIFT_TASK_GROUP_DEBUG_LOG(this, "WATCH OUT, SET WAITER ONTO waitQueue.head = %p", waitQueue.load(std::memory_order_relaxed));
+    SWIFT_TASK_GROUP_DEBUG_LOG(
+        this, "WATCH OUT, SET WAITER %p ONTO waitQueue.head = %p", waitingTask,
+        waitQueue.load(std::memory_order_relaxed));
     if (waitQueue.compare_exchange_weak(
         waitHead, waitingTask,
         /*success*/ std::memory_order_release,
@@ -1945,7 +1962,7 @@ void TaskGroupBase::waitAll(SwiftError* bodyError, AsyncTask *waitingTask,
 
   auto context = static_cast<TaskFutureWaitAsyncContext *>(rawContext);
   context->ResumeParent =
-      std::bit_cast<TaskContinuationFunction *>(resumeFunction);
+      function_cast<TaskContinuationFunction *>(resumeFunction);
   context->Parent = callerContext;
   context->errorResult = nullptr;
   context->successResultPointer = resultPointer;
@@ -2025,6 +2042,7 @@ void TaskGroupBase::waitAll(SwiftError* bodyError, AsyncTask *waitingTask,
   if (bodyError && isDiscardingResults() && readyQueue.isEmpty()) {
     auto discardingGroup = asDiscardingImpl(this);
     auto readyItem = ReadyQueueItem::getRawError(discardingGroup, bodyError);
+    SWIFT_TASK_GROUP_DEBUG_LOG(this, "enqueue %#" PRIxPTR, readyItem.storage);
     readyQueue.enqueue(readyItem);
   }
 
@@ -2116,8 +2134,8 @@ bool TaskGroupBase::cancelAll(AsyncTask *owningTask) {
 
   // Cancel all the child tasks.  TaskGroup is not a Sendable type,
   // so cancelAll() can only be called from the owning task.  This
-  // satisfies the precondition on cancelAllChildren_unlocked().
-  _swift_taskGroup_cancelAllChildren_unlocked(asAbstract(this), owningTask);
+  // satisfies the precondition on cancel_unlocked().
+  _swift_taskGroup_cancel_unlocked(asAbstract(this), owningTask);
 
   return true;
 }
@@ -2126,8 +2144,8 @@ SWIFT_CC(swift)
 static void swift_task_cancel_group_child_tasksImpl(TaskGroup *group) {
   // TaskGroup is not a Sendable type, and so this operation (which is not
   // currently exposed in the API) can only be called from the owning
-  // task.  This satisfies the precondition on cancelAllChildren_unlocked().
-  _swift_taskGroup_cancelAllChildren_unlocked(group, swift_task_getCurrent());
+  // task.  This satisfies the precondition on cancel_unlocked().
+  _swift_taskGroup_cancel_unlocked(group, swift_task_getCurrent());
 }
 
 // =============================================================================
diff --git a/stdlib/public/Concurrency/TaskGroup.swift b/stdlib/public/Concurrency/TaskGroup.swift
index 3b0e4728c5cac..501404094c993 100644
--- a/stdlib/public/Concurrency/TaskGroup.swift
+++ b/stdlib/public/Concurrency/TaskGroup.swift
@@ -16,8 +16,11 @@ import Swift
 
 /// Starts a new scope that can contain a dynamic number of child tasks.
 ///
-/// A group waits for all of its child tasks
-/// to complete or be canceled before it returns.
+/// A group *always* waits for all of its child tasks
+/// to complete before it returns. Even canceled tasks must run until
+/// completion before this function returns.
+/// Canceled child tasks cooperatively react to cancellation and attempt
+/// to return as early as possible.
 /// After this function returns, the task group is always empty.
 ///
 /// To collect the results of the group's child tasks,
@@ -39,29 +42,9 @@ import Swift
 ///     group.cancelAll()
 ///     return first + second
 ///
-/// Task Group Cancellation
-/// =======================
+/// Refer to ``TaskGroup`` documentation for detailed discussion of semantics shared between all task groups.
 ///
-/// You can cancel a task group and all of its child tasks
-/// by calling the `cancelAll()` method on the task group,
-/// or by canceling the task in which the group is running.
-///
-/// If you call `addTask(name:priority:operation:)` to create a new task in a canceled group,
-/// that task is immediately canceled after creation.
-/// Alternatively, you can call `addTaskUnlessCancelled(name:priority:operation:)`,
-/// which doesn't create the task if the group has already been canceled.
-/// Choosing between these two functions
-/// lets you control how to react to cancellation within a group:
-/// some child tasks need to run regardless of cancellation,
-/// but other tasks are better not even being created
-/// when you know they can't produce useful results.
-///
-/// Because the tasks you add to a group with this method are nonthrowing,
-/// those tasks can't respond to cancellation by throwing `CancellationError`.
-/// The tasks must handle cancellation in some other way,
-/// such as returning the work completed so far, returning an empty result, or returning `nil`.
-/// For tasks that need to handle cancellation by throwing an error,
-/// use the `withThrowingTaskGroup(of:returning:body:)` method instead.
+/// - SeeAlso: ``TaskGroup``
 @available(SwiftStdlib 5.1, *)
 #if !hasFeature(Embedded)
 @backDeployed(before: SwiftStdlib 6.0)
@@ -126,10 +109,10 @@ public func _unsafeInheritExecutor_withTaskGroup<ChildTaskResult, GroupResult>(
 
 /// Starts a new scope that can contain a dynamic number of throwing child tasks.
 ///
-/// A group waits for all of its child tasks
-/// to complete before it returns. Even cancelled tasks must run until
+/// A group *always* waits for all of its child tasks
+/// to complete before it returns. Even canceled tasks must run until
 /// completion before this function returns.
-/// Cancelled child tasks cooperatively react to cancellation and attempt
+/// Canceled child tasks cooperatively react to cancellation and attempt
 /// to return as early as possible.
 /// After this function returns, the task group is always empty.
 ///
@@ -152,23 +135,6 @@ public func _unsafeInheritExecutor_withTaskGroup<ChildTaskResult, GroupResult>(
 ///     group.cancelAll()
 ///     return first + second
 ///
-/// Task Group Cancellation
-/// =======================
-///
-/// You can cancel a task group and all of its child tasks
-/// by calling the `cancelAll()` method on the task group,
-/// or by canceling the task in which the group is running.
-///
-/// If you call `addTask(name:priority:operation:)` to create a new task in a canceled group,
-/// that task is immediately canceled after creation.
-/// Alternatively, you can call `addTaskUnlessCancelled(name:priority:operation:)`,
-/// which doesn't create the task if the group has already been canceled.
-/// Choosing between these two functions
-/// lets you control how to react to cancellation within a group:
-/// some child tasks need to run regardless of cancellation,
-/// but other tasks are better not even being created
-/// when you know they can't produce useful results.
-///
 /// Error Handling
 /// ==============
 ///
@@ -199,6 +165,12 @@ public func _unsafeInheritExecutor_withTaskGroup<ChildTaskResult, GroupResult>(
 /// in the corresponding call to `Group.next()`,
 /// which gives you a chance to handle the individual error
 /// or to let the group rethrow the error.
+///
+/// Refer to ``TaskGroup`` documentation for detailed discussion of semantics shared between all task groups.
+///
+/// - SeeAlso: ``TaskGroup``
+/// - SeeAlso: ``ThrowingTaskGroup``
+/// - SeeAlso: ``ThrowingDiscardingTaskGroup``
 @available(SwiftStdlib 5.1, *)
 #if !hasFeature(Embedded)
 @backDeployed(before: SwiftStdlib 6.0)
@@ -290,24 +262,93 @@ public func _unsafeInheritExecutor_withThrowingTaskGroup<ChildTaskResult, GroupR
 /// and mutation operations can't be performed
 /// from a concurrent execution context like a child task.
 ///
+/// Structured Concurrency
+/// ======================
+///
+/// Structured concurrency is a way to organize your program, and tasks, in such a way that
+/// tasks don't outlive the scope in which they are created. Within a structured task hierarchy,
+/// no child task remains running longer than its parent task. This guarantee simplifies reasoning about resource usage,
+/// and is a powerful mechanism that you can use to write well-behaved concurrent programs.
+///
+/// A task group is the primary way to create structured concurrency tasks in Swift.
+/// Another way of creating structured tasks is an `async let` declaration.
+///
+/// Structured concurrency tasks are often called "child tasks" because of their relationship with their parent task.
+/// A child task inherits the parent's priority, task-local values, and is structured in the sense that its
+/// lifetime never exceeds the lifetime of the parent task.
+///
+/// A task group *always* waits for all child tasks to complete before it's destroyed.
+/// Specifically, `with...TaskGroup` APIs don't return until all the child tasks
+/// created in the group's scope have completed running.
+///
+/// Structured concurrency APIs (including task groups and `async let`), *always* waits for the
+/// completion of tasks contained within their scope before returning. Specifically, this means that
+/// even if you await a single task result and return it from a `withTaskGroup` function body,
+/// the group automatically waits for all the remaining tasks before returning:
+///
+///     func takeFirst(actions: [@Sendable () -> Int]) async -> Int? {
+///         await withTaskGroup { group in
+///             for action in actions {
+///                 group.addTask { action() }
+///             }
+///
+///             return await group.next() // return the first action to complete
+///         } // the group will ALWAYS await the completion of all the actions (!)
+///     }
+///
+/// In the above example, even though the code returns the first collected integer from all actions added to the task group,
+/// the task group *always*, automatically, waits for the completion of all the resulting tasks.
+///
+/// You can use `group.cancelAll()` to signal cancellation to the remaining in-progress tasks,
+/// however this doesn't interrupt their execution automatically.
+/// Rather, the child tasks need to cooperatively react to the cancellation,
+/// and return early if that's possible.
+///
+/// To create unstructured concurrency tasks, you can use ``Task.init``, ``Task.detached`` or ``Task.immediate``.
+///
+/// Task Group Cancellation
+/// =======================
+///
+/// You can cancel a task group and all of its child tasks
+/// by calling the `cancelAll()` method on the task group,
+/// or by canceling the task in which the group is running.
+///
+/// If you call `addTask(name:priority:operation:)` to create a new task in a canceled group,
+/// that task is immediately canceled after creation.
+/// Alternatively, you can call `addTaskUnlessCancelled(name:priority:operation:)`,
+/// which doesn't create the task if the group has already been canceled.
+/// Choosing between these two functions
+/// lets you control how to react to cancellation within a group:
+/// some child tasks need to run regardless of cancellation,
+/// but other tasks are better not even being created
+/// when you know they can't produce useful results.
+///
+/// In nonthrowing task groups the tasks you add to a group with this method are nonthrowing,
+/// those tasks can't respond to cancellation by throwing `CancellationError`.
+/// The tasks must handle cancellation in some other way,
+/// such as returning the work completed so far, returning an empty result, or returning `nil`.
+/// For tasks that need to handle cancellation by throwing an error,
+/// use the `withThrowingTaskGroup(of:returning:body:)` method instead.
+///
 /// ### Task execution order
 ///
 /// Tasks added to a task group execute concurrently, and may be scheduled in
 /// any order.
 ///
 /// ### Cancellation behavior
-/// A task group becomes cancelled in one of the following ways:
 ///
-/// - when ``cancelAll()`` is invoked on it,
-/// - when the ``Task`` running this task group is cancelled.
+/// A task group becomes canceled in one of the following ways:
+///
+/// - When ``cancelAll()`` is invoked on it.
+/// - When the ``Task`` running this task group is canceled.
 ///
-/// Since a `TaskGroup` is a structured concurrency primitive, cancellation is
+/// Because a `TaskGroup` is a structured concurrency primitive, cancellation is
 /// automatically propagated through all of its child-tasks (and their child
 /// tasks).
 ///
-/// A cancelled task group can still keep adding tasks, however they will start
-/// being immediately cancelled, and may act accordingly to this. To avoid adding
-/// new tasks to an already cancelled task group, use ``addTaskUnlessCancelled(name:priority:body:)``
+/// A canceled task group can still keep adding tasks, however they will start
+/// being immediately canceled, and might respond accordingly. To avoid adding
+/// new tasks to an already canceled task group, use ``addTaskUnlessCancelled(name:priority:body:)``
 /// rather than the plain ``addTask(name:priority:body:)`` which adds tasks unconditionally.
 ///
 /// For information about the language-level concurrency model that `TaskGroup` is part of,
@@ -316,6 +357,9 @@ public func _unsafeInheritExecutor_withThrowingTaskGroup<ChildTaskResult, GroupR
 /// [concurrency]: https://docs.swift.org/swift-book/LanguageGuide/Concurrency.html
 /// [tspl]: https://docs.swift.org/swift-book/
 ///
+/// - SeeAlso: ``ThrowingTaskGroup``
+/// - SeeAlso: ``DiscardingTaskGroup``
+/// - SeeAlso: ``ThrowingDiscardingTaskGroup``
 @available(SwiftStdlib 5.1, *)
 @frozen
 public struct TaskGroup<ChildTaskResult: Sendable> {
@@ -364,7 +408,7 @@ public struct TaskGroup<ChildTaskResult: Sendable> {
   ///     return collected
   ///
   /// Awaiting on an empty group
-  /// immediate returns `nil` without suspending.
+  /// immediately returns `nil` without suspending.
   ///
   /// You can also use a `for`-`await`-`in` loop to collect results of a task group:
   ///
@@ -423,7 +467,7 @@ public struct TaskGroup<ChildTaskResult: Sendable> {
   ///
   /// At the start of the body of a `withTaskGroup(of:returning:body:)` call,
   /// the task group is always empty.
-  /// It`s guaranteed to be empty when returning from that body
+  /// It's guaranteed to be empty when returning from that body
   /// because a task group waits for all child tasks to complete before returning.
   ///
   /// - Returns: `true` if the group has no pending tasks; otherwise `false`.
@@ -436,7 +480,7 @@ public struct TaskGroup<ChildTaskResult: Sendable> {
   /// If you add a task to a group after canceling the group,
   /// that task is canceled immediately after being added to the group.
   ///
-  /// Immediately cancelled child tasks should therefore cooperatively check for and
+  /// Immediately canceled child tasks should therefore cooperatively check for and
   /// react  to cancellation, e.g. by throwing an `CancellationError` at their
   /// earliest convenience, or otherwise handling the cancellation.
   ///
@@ -498,24 +542,22 @@ extension TaskGroup: Sendable { }
 /// and mutation operations can't be performed
 /// from concurrent execution contexts like a child task.
 ///
-/// ### Task execution order
-/// Tasks added to a task group execute concurrently, and may be scheduled in
-/// any order.
+/// Refer to ``TaskGroup`` documentation for detailed discussion of semantics shared between all task groups.
 ///
 /// ### Cancellation behavior
-/// A task group becomes cancelled in one of the following ways:
+/// A task group becomes canceled in one of the following ways:
 ///
 /// - when ``cancelAll()`` is invoked on it,
 /// - when an error is thrown out of the `withThrowingTaskGroup(...) { }` closure,
-/// - when the ``Task`` running this task group is cancelled.
+/// - when the ``Task`` running this task group is canceled.
 ///
 /// Since a `ThrowingTaskGroup` is a structured concurrency primitive, cancellation is
 /// automatically propagated through all of its child-tasks (and their child
 /// tasks).
 ///
-/// A cancelled task group can still keep adding tasks, however they will start
-/// being immediately cancelled, and may act accordingly to this. To avoid adding
-/// new tasks to an already cancelled task group, use ``addTaskUnlessCancelled(priority:body:)``
+/// A canceled task group can still keep adding tasks, however they will start
+/// being immediately canceled, and may act accordingly to this. To avoid adding
+/// new tasks to an already canceled task group, use ``addTaskUnlessCancelled(priority:body:)``
 /// rather than the plain ``addTask(priority:body:)`` which adds tasks unconditionally.
 ///
 /// For information about the language-level concurrency model that `ThrowingTaskGroup` is part of,
@@ -524,6 +566,9 @@ extension TaskGroup: Sendable { }
 /// [concurrency]: https://docs.swift.org/swift-book/LanguageGuide/Concurrency.html
 /// [tspl]: https://docs.swift.org/swift-book/
 ///
+/// - SeeAlso: ``TaskGroup``
+/// - SeeAlso: ``DiscardingTaskGroup``
+/// - SeeAlso: ``ThrowingDiscardingTaskGroup``
 @available(SwiftStdlib 5.1, *)
 @frozen
 public struct ThrowingTaskGroup<ChildTaskResult: Sendable, Failure: Error> {
@@ -569,7 +614,7 @@ public struct ThrowingTaskGroup<ChildTaskResult: Sendable, Failure: Error> {
   /// Wait for all of the group's remaining tasks to complete.
   ///
   /// If any of the tasks throw, the *first* error thrown is captured
-  /// and re-thrown by this method although the task group is *not* cancelled
+  /// and re-thrown by this method although the task group is *not* canceled
   /// when this happens.
   ///
   /// ### Cancelling the task group on first error
@@ -761,7 +806,7 @@ public struct ThrowingTaskGroup<ChildTaskResult: Sendable, Failure: Error> {
   /// If you add a task to a group after canceling the group,
   /// that task is canceled immediately after being added to the group.
   ///
-  /// Immediately cancelled child tasks should therefore cooperatively check for and
+  /// Immediately canceled child tasks should therefore cooperatively check for and
   /// react  to cancellation, e.g. by throwing an `CancellationError` at their
   /// earliest convenience, or otherwise handling the cancellation.
   ///
diff --git a/stdlib/public/Concurrency/TaskPrivate.h b/stdlib/public/Concurrency/TaskPrivate.h
index 2235e7a687b23..3587c68f70bea 100644
--- a/stdlib/public/Concurrency/TaskPrivate.h
+++ b/stdlib/public/Concurrency/TaskPrivate.h
@@ -89,16 +89,16 @@ AsyncTask *_swift_task_clearCurrent();
 /// Set the active task reference for the current thread.
 AsyncTask *_swift_task_setCurrent(AsyncTask *newTask);
 
-/// Cancel all the child tasks that belong to `group`.
+/// Cancel the task group and all the child tasks that belong to `group`.
 ///
 /// The caller must guarantee that this is called while holding the owning
 /// task's status record lock.
-void _swift_taskGroup_cancelAllChildren(TaskGroup *group);
+void _swift_taskGroup_cancel(TaskGroup *group);
 
-/// Cancel all the child tasks that belong to `group`.
+/// Cancel the task group and all the child tasks that belong to `group`.
 ///
 /// The caller must guarantee that this is called from the owning task.
-void _swift_taskGroup_cancelAllChildren_unlocked(TaskGroup *group,
+void _swift_taskGroup_cancel_unlocked(TaskGroup *group,
                                                  AsyncTask *owningTask);
 
 /// Remove the given task from the given task group.
@@ -728,10 +728,11 @@ class alignas(2 * sizeof(void*)) ActiveTaskStatus {
     return record_iterator::rangeBeginning(getInnermostRecord());
   }
 
-  void traceStatusChanged(AsyncTask *task, bool isStarting) {
+  void traceStatusChanged(AsyncTask *task, bool isStarting, bool wasRunning) {
     concurrency::trace::task_status_changed(
         task, static_cast<uint8_t>(getStoredPriority()), isCancelled(),
-        isStoredPriorityEscalated(), isStarting, isRunning(), isEnqueued());
+        isStoredPriorityEscalated(), isStarting, isRunning(), isEnqueued(),
+        wasRunning);
   }
 };
 
@@ -766,9 +767,11 @@ struct AsyncTask::PrivateStorage {
   alignas(ActiveTaskStatus) char StatusStorage[sizeof(ActiveTaskStatus)];
 
   /// The allocator for the task stack.
-  /// Currently 2 words + 8 bytes.
+  /// Currently 2 words + 4 bytes.
   TaskAllocator Allocator;
 
+  // Four bytes of padding here (on 64-bit)
+
   /// Storage for task-local values.
   /// Currently one word.
   TaskLocal::Storage Local;
@@ -776,6 +779,8 @@ struct AsyncTask::PrivateStorage {
   /// The top 32 bits of the task ID. The bottom 32 bits are in Job::Id.
   uint32_t Id;
 
+  // Another four bytes of padding here too (on 64-bit)
+
   /// Base priority of Task - set only at creation time of task.
   /// Current max priority of task is ActiveTaskStatus.
   ///
@@ -825,12 +830,8 @@ struct AsyncTask::PrivateStorage {
     // result of the task
     auto oldStatus = task->_private()._status().load(std::memory_order_relaxed);
     while (true) {
-      // Task is completing
       assert(oldStatus.getInnermostRecord() == NULL &&
              "Status records should have been removed by this time!");
-      assert(!oldStatus.isStatusRecordLocked() &&
-             "Task is completing, cannot be locked anymore!");
-
       assert(oldStatus.isRunning());
 
       // Remove drainer, enqueued and override bit if any
@@ -854,6 +855,8 @@ struct AsyncTask::PrivateStorage {
       }
     }
 
+    _swift_tsan_release(task);
+
     // Destroy and deallocate any remaining task local items since the task is
     // completed. We need to do this before we destroy the task local
     // deallocator.
@@ -969,7 +972,7 @@ inline void AsyncTask::flagAsRunning() {
       if (_private()._status().compare_exchange_weak(oldStatus, newStatus,
                /* success */ std::memory_order_relaxed,
                /* failure */ std::memory_order_relaxed)) {
-        newStatus.traceStatusChanged(this, true);
+        newStatus.traceStatusChanged(this, true, oldStatus.isRunning());
         adoptTaskVoucher(this);
         swift_task_enterThreadLocalContext(
             (char *)&_private().ExclusivityAccessSet[0]);
diff --git a/stdlib/public/Concurrency/TaskSleep.swift b/stdlib/public/Concurrency/TaskSleep.swift
index 653a343c546d8..b9994e01698eb 100644
--- a/stdlib/public/Concurrency/TaskSleep.swift
+++ b/stdlib/public/Concurrency/TaskSleep.swift
@@ -28,9 +28,9 @@ extension Task where Success == Never, Failure == Never {
           priority: Int(Task.currentPriority.rawValue),
           continuation: continuation)
 
-      if #available(SwiftStdlib 6.2, *) {
+      if #available(StdlibDeploymentTarget 6.2, *) {
         #if !$Embedded
-        if let executor = Task.currentSchedulableExecutor {
+        if let executor = Task.currentSchedulingExecutor {
           executor.enqueue(ExecutorJob(context: job),
                            after: .nanoseconds(duration),
                            clock: .continuous)
@@ -39,7 +39,7 @@ extension Task where Success == Never, Failure == Never {
         #endif
       }
 
-      // If there is no current schedulable executor, fall back to
+      // If there is no current scheduling executor, fall back to
       // _enqueueJobGlobalWithDelay()
       _enqueueJobGlobalWithDelay(duration, job)
     }
@@ -272,9 +272,9 @@ extension Task where Success == Never, Failure == Never {
 
               let job = Builtin.convertTaskToJob(sleepTask)
 
-              if #available(SwiftStdlib 6.2, *) {
+              if #available(StdlibDeploymentTarget 6.2, *) {
                 #if !$Embedded
-                if let executor = Task.currentSchedulableExecutor {
+                if let executor = Task.currentSchedulingExecutor {
                   executor.enqueue(ExecutorJob(context: job),
                                    after: .nanoseconds(duration),
                                    clock: .continuous)
@@ -283,7 +283,7 @@ extension Task where Success == Never, Failure == Never {
                 #endif
               }
 
-              // If there is no current schedulable executor, fall back to
+              // If there is no current scheduling executor, fall back to
               // _enqueueJobGlobalWithDelay()
               _enqueueJobGlobalWithDelay(duration, job)
               return
diff --git a/stdlib/public/Concurrency/TaskSleepDuration.swift b/stdlib/public/Concurrency/TaskSleepDuration.swift
index d9e3876c69534..27f35eb321b7c 100644
--- a/stdlib/public/Concurrency/TaskSleepDuration.swift
+++ b/stdlib/public/Concurrency/TaskSleepDuration.swift
@@ -13,51 +13,70 @@
 import Swift
 
 #if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
-@available(SwiftStdlib 5.7, *)
-fileprivate func timestamp<C: Clock>(for instant: C.Instant, clock: C)
-  -> (clockID: _ClockID, seconds: Int64, nanoseconds: Int64) {
-  var clockID: _ClockID
-  if #available(SwiftStdlib 6.2, *) {
-    if clock.traits.contains(.continuous) {
-      clockID = .continuous
-    } else {
-      clockID = .suspending
-    }
-  } else {
-    Builtin.unreachable()
+@_unavailableInEmbedded
+extension ContinuousClock {
+  func timestamp(for instant: Instant)
+    -> (clockID: _ClockID, seconds: Int64, nanoseconds: Int64)
+  {
+    let (seconds, nanoseconds) = durationComponents(for: instant._value)
+    return (clockID: .continuous, seconds: seconds, nanoseconds: nanoseconds)
   }
 
-  var seconds: Int64 = 0
-  var nanoseconds: Int64 = 0
-  unsafe _getTime(seconds: &seconds,
-                  nanoseconds: &nanoseconds,
-                  clock: clockID.rawValue)
-
-  let delta: Swift.Duration
-  if #available(SwiftStdlib 6.2, *) {
-    delta = clock.convert(from: clock.now.duration(to: instant))!
-  } else {
-    Builtin.unreachable()
+  func durationComponents(for duration: Duration)
+    -> (seconds: Int64, nanoseconds: Int64)
+  {
+    let (seconds, attoseconds) = duration.components
+    let nanoseconds = attoseconds / 1_000_000_000
+    return (seconds: seconds, nanoseconds: nanoseconds)
   }
+}
 
-  let (deltaSeconds, deltaAttoseconds) = delta.components
-  let deltaNanoseconds = deltaAttoseconds / 1_000_000_000
-  seconds += deltaSeconds
-  nanoseconds += deltaNanoseconds
-  if nanoseconds > 1_000_000_000 {
-    seconds += 1
-    nanoseconds -= 1_000_000_000
+@_unavailableInEmbedded
+extension SuspendingClock {
+  func timestamp(for instant: Instant)
+    -> (clockID: _ClockID, seconds: Int64, nanoseconds: Int64)
+  {
+    let (seconds, nanoseconds) = durationComponents(for: instant._value)
+    return (clockID: .suspending, seconds: seconds, nanoseconds: nanoseconds)
   }
 
-  return (clockID: clockID,
-          seconds: Int64(seconds),
-          nanoseconds: Int64(nanoseconds))
+  func durationComponents(for duration: Duration)
+    -> (seconds: Int64, nanoseconds: Int64)
+  {
+    let (seconds, attoseconds) = duration.components
+    let nanoseconds = attoseconds / 1_000_000_000
+    return (seconds: seconds, nanoseconds: nanoseconds)
+  }
 }
 
-@available(SwiftStdlib 5.7, *)
+fileprivate func timestamp<C: Clock>(for instant: C.Instant, clock: C)
+  -> (clockID: _ClockID, seconds: Int64, nanoseconds: Int64) {
+  #if !$Embedded
+  if let continuousClock = clock as? ContinuousClock {
+    return continuousClock.timestamp(for: instant as! ContinuousClock.Instant)
+  } else if let suspendingClock = clock as? SuspendingClock {
+    return suspendingClock.timestamp(for: instant as! SuspendingClock.Instant)
+  }
+  #endif
+  fatalError("unknown clock in fallback path")
+}
+
+fileprivate func durationComponents<C: Clock>(for duration: C.Duration, clock: C)
+  -> (seconds: Int64, nanoseconds: Int64) {
+  #if !$Embedded
+  if let continuousClock = clock as? ContinuousClock {
+    return continuousClock.durationComponents(for: duration as! ContinuousClock.Duration)
+  } else if let suspendingClock = clock as? SuspendingClock {
+    return suspendingClock.durationComponents(for: duration as! SuspendingClock.Duration)
+  }
+  #endif
+  fatalError("unknown clock in fallback path")
+}
+
+@available(StdlibDeploymentTarget 5.7, *)
 @_unavailableInEmbedded
 extension Task where Success == Never, Failure == Never {
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   internal static func _sleep<C: Clock>(
     until instant: C.Instant,
     tolerance: C.Duration?,
@@ -97,9 +116,9 @@ extension Task where Success == Never, Failure == Never {
 
               let job = Builtin.convertTaskToJob(sleepTask)
 
-              if #available(SwiftStdlib 6.2, *) {
+              if #available(StdlibDeploymentTarget 6.2, *) {
                 #if !$Embedded
-                if let executor = Task.currentSchedulableExecutor {
+                if let executor = Task.currentSchedulingExecutor {
                   executor.enqueue(ExecutorJob(context: job),
                                    at: instant,
                                    tolerance: tolerance,
@@ -108,35 +127,34 @@ extension Task where Success == Never, Failure == Never {
                 }
                 #endif
               } else {
-                Builtin.unreachable()
+                fatalError("we shouldn't get here; if we have, availability is broken")
               }
 
-              // If there is no current schedulable executor, fall back to
+              // If there is no current scheduling executor, fall back to
               // calling _enqueueJobGlobalWithDeadline().
               let (clockID, seconds, nanoseconds) = timestamp(for: instant,
                                                               clock: clock)
               let toleranceSeconds: Int64
               let toleranceNanoseconds: Int64
-              if #available(SwiftStdlib 6.2, *) {
-                if let tolerance = tolerance,
-                   let components = clock.convert(from: tolerance)?.components {
-                  toleranceSeconds = components.seconds
-                  toleranceNanoseconds = components.attoseconds / 1_000_000_000
+              if #available(StdlibDeploymentTarget 6.2, *) {
+                if let tolerance = tolerance {
+                  (toleranceSeconds, toleranceNanoseconds)
+                    = durationComponents(for: tolerance, clock: clock)
                 } else {
                   toleranceSeconds = 0
                   toleranceNanoseconds = -1
                 }
               } else {
-                Builtin.unreachable()
+                fatalError("we shouldn't get here; if we have, availability is broken")
               }
 
-              if #available(SwiftStdlib 5.9, *) {
+              if #available(StdlibDeploymentTarget 5.9, *) {
                 _enqueueJobGlobalWithDeadline(
                   seconds, nanoseconds,
                   toleranceSeconds, toleranceNanoseconds,
                   clockID.rawValue, UnownedJob(context: job))
               } else {
-                Builtin.unreachable()
+                fatalError("we shouldn't get here; if we have, availability is broken")
               }
               return
 
@@ -209,7 +227,7 @@ extension Task where Success == Never, Failure == Never {
 
   /// Suspends the current task for the given duration.
   ///
-  /// If the task is cancelled before the time ends, this function throws
+  /// If the task is canceled before the time ends, this function throws
   /// `CancellationError`.
   ///
   /// This function doesn't block the underlying thread.
diff --git a/stdlib/public/Concurrency/TaskStatus.cpp b/stdlib/public/Concurrency/TaskStatus.cpp
index 38cc28b45535e..c4c5d849161c9 100644
--- a/stdlib/public/Concurrency/TaskStatus.cpp
+++ b/stdlib/public/Concurrency/TaskStatus.cpp
@@ -67,7 +67,19 @@ static void withStatusRecordLock(
   // see that the is-locked bit is now set, and then wait for the lock.
   task->_private().statusLock.lock();
 
-  bool alreadyLocked = status.isStatusRecordLocked();
+  bool alreadyLocked = false;
+
+  // `status` was loaded before we acquired the lock. If its is-locked bit is
+  // not set, then we know that this thread doesn't already hold the lock.
+  // However, if the is-locked bit is set, then we don't know if this thread
+  // held the lock or another thread did. In that case, we reload the status
+  // after acquiring the lock. If the reloaded status still has the is-locked
+  // bit set, then we know it's this thread. If it doesn't, then we know it was
+  // a different thread.
+  if (status.isStatusRecordLocked()) {
+    status = task->_private()._status().load(std::memory_order_relaxed);
+    alreadyLocked = status.isStatusRecordLocked();
+  }
 
   // If it's already locked then this thread is the thread that locked it, and
   // we can leave that bit alone here.
@@ -82,8 +94,9 @@ static void withStatusRecordLock(
               status, newStatus,
               /*success*/ SWIFT_MEMORY_ORDER_CONSUME,
               /*failure*/ std::memory_order_relaxed)) {
+        bool wasRunning = status.isRunning();
         status = newStatus;
-        status.traceStatusChanged(task, false);
+        status.traceStatusChanged(task, false, wasRunning);
         break;
       }
     }
@@ -118,7 +131,7 @@ static void withStatusRecordLock(
             status, newStatus,
             /*success*/ std::memory_order_relaxed,
             /*failure*/ std::memory_order_relaxed)) {
-      newStatus.traceStatusChanged(task, false);
+      newStatus.traceStatusChanged(task, false, status.isRunning());
       break;
     }
   }
@@ -184,7 +197,7 @@ bool swift::addStatusRecord(AsyncTask *task, TaskStatusRecord *newRecord,
       if (task->_private()._status().compare_exchange_weak(oldStatus, newStatus,
               /*success*/ std::memory_order_release,
               /*failure*/ std::memory_order_relaxed)) {
-        newStatus.traceStatusChanged(task, false);
+        newStatus.traceStatusChanged(task, false, oldStatus.isRunning());
         return true;
       } else {
         // Retry
@@ -290,7 +303,7 @@ void swift::removeStatusRecord(AsyncTask *task, TaskStatusRecord *record,
             oldStatus, newStatus,
             /*success*/ std::memory_order_relaxed,
             /*failure*/ std::memory_order_relaxed)) {
-      newStatus.traceStatusChanged(task, false);
+      newStatus.traceStatusChanged(task, false, oldStatus.isRunning());
       return;
     }
 
@@ -509,8 +522,8 @@ swift_task_pushTaskExecutorPreferenceImpl(TaskExecutorRef taskExecutor) {
           // the executor.
           /*retainedExecutor=*/false);
   SWIFT_TASK_DEBUG_LOG("[TaskExecutorPreference] Create task executor "
-                       "preference record %p for task:%p",
-                       allocation, task);
+                       "preference record:%p taskExecutor:%p for task:%p",
+                       allocation, taskExecutor.getIdentity(), task);
 
 
   addStatusRecord(task, record,
@@ -577,8 +590,8 @@ void AsyncTask::pushInitialTaskExecutorPreference(
       ::new (allocation) TaskExecutorPreferenceStatusRecord(
           preferredExecutor, /*ownsExecutor=*/owned);
   SWIFT_TASK_DEBUG_LOG("[InitialTaskExecutorPreference] Create a task "
-                       "preference record %p for task:%p",
-                       record, this);
+                       "preference record:%p taskExecutor:%p for task:%p",
+                       record, preferredExecutor.getIdentity(), this);
 
   addStatusRecord(this, record,
                   [&](ActiveTaskStatus oldStatus, ActiveTaskStatus &newStatus) {
@@ -642,8 +655,13 @@ void AsyncTask::pushInitialTaskName(const char* _taskName) {
   auto taskNameLen = strlen(_taskName);
   char* taskNameCopy = reinterpret_cast<char*>(
       _swift_task_alloc_specific(this, taskNameLen + 1/*null terminator*/));
+#if defined(_WIN32)
+  static_cast<void>(strncpy_s(taskNameCopy, taskNameLen + 1,
+                              _taskName, _TRUNCATE));
+#else
   (void) strncpy(/*dst=*/taskNameCopy, /*src=*/_taskName, taskNameLen);
   taskNameCopy[taskNameLen] = '\0'; // make sure we null-terminate
+#endif
 
   auto record =
       ::new (allocation) TaskNameStatusRecord(taskNameCopy);
@@ -776,11 +794,13 @@ void swift::_swift_taskGroup_detachChild(TaskGroup *group,
   });
 }
 
-/// Cancel all the child tasks that belong to `group`.
+/// Cancel the task group and all the child tasks that belong to `group`.
 ///
 /// The caller must guarantee that this is called while holding the owning
 /// task's status record lock.
-void swift::_swift_taskGroup_cancelAllChildren(TaskGroup *group) {
+void swift::_swift_taskGroup_cancel(TaskGroup *group) {
+  (void) group->statusCancel();
+
   // Because only the owning task of the task group can modify the
   // child list of a task group status record, and it can only do so
   // while holding the owning task's status record lock, we do not need
@@ -789,10 +809,10 @@ void swift::_swift_taskGroup_cancelAllChildren(TaskGroup *group) {
     swift_task_cancel(childTask);
 }
 
-/// Cancel all the child tasks that belong to `group`.
+/// Cancel the task group and all the child tasks that belong to `group`.
 ///
 /// The caller must guarantee that this is called from the owning task.
-void swift::_swift_taskGroup_cancelAllChildren_unlocked(TaskGroup *group,
+void swift::_swift_taskGroup_cancel_unlocked(TaskGroup *group,
                                                         AsyncTask *owningTask) {
   // Early out. If there are no children, there's nothing to do. We can safely
   // check this without locking, since this can only be concurrently mutated
@@ -801,7 +821,7 @@ void swift::_swift_taskGroup_cancelAllChildren_unlocked(TaskGroup *group,
     return;
 
   withStatusRecordLock(owningTask, [&group](ActiveTaskStatus status) {
-    _swift_taskGroup_cancelAllChildren(group);
+    _swift_taskGroup_cancel(group);
   });
 }
 
@@ -825,7 +845,7 @@ static void performCancellationAction(TaskStatusRecord *record) {
   // under the synchronous control of the task that owns the group.
   case TaskStatusRecordKind::TaskGroup: {
     auto groupRecord = cast<TaskGroupTaskStatusRecord>(record);
-    _swift_taskGroup_cancelAllChildren(groupRecord->getGroup());
+    _swift_taskGroup_cancel(groupRecord->getGroup());
     return;
   }
 
@@ -885,7 +905,7 @@ static void swift_task_cancelImpl(AsyncTask *task) {
     }
   }
 
-  newStatus.traceStatusChanged(task, false);
+  newStatus.traceStatusChanged(task, false, oldStatus.isRunning());
   if (newStatus.getInnermostRecord() == nullptr) {
      // No records, nothing to propagate
      return;
diff --git a/stdlib/public/Concurrency/Tracing.h b/stdlib/public/Concurrency/Tracing.h
index 1e084ce6bd66c..b26122f402ebe 100644
--- a/stdlib/public/Concurrency/Tracing.h
+++ b/stdlib/public/Concurrency/Tracing.h
@@ -63,7 +63,8 @@ void task_create(AsyncTask *task, AsyncTask *parent, TaskGroup *group,
 void task_destroy(AsyncTask *task);
 
 void task_status_changed(AsyncTask *task, uint8_t maxPriority, bool isCancelled,
-                         bool isEscalated, bool isStarting, bool isRunning, bool isEnqueued);
+                         bool isEscalated, bool isStarting, bool isRunning,
+                         bool isEnqueued, bool wasRunning);
 
 void task_flags_changed(AsyncTask *task, uint8_t jobPriority, bool isChildTask,
                         bool isFuture, bool isGroupChildTask,
diff --git a/stdlib/public/Concurrency/TracingSignpost.h b/stdlib/public/Concurrency/TracingSignpost.h
index 61ae44602400b..b44304e28254d 100644
--- a/stdlib/public/Concurrency/TracingSignpost.h
+++ b/stdlib/public/Concurrency/TracingSignpost.h
@@ -28,6 +28,10 @@
 #include <os/log.h>
 #include <os/signpost.h>
 
+#if defined(__arm64__) && __has_include(<os/apt_private.h>)
+#include <os/apt_private.h>
+#endif
+
 // Compatibility notes:
 //
 // These signposts can be read by external software that isn't synced with the
@@ -210,7 +214,24 @@ inline void task_destroy(AsyncTask *task) {
 
 inline void task_status_changed(AsyncTask *task, uint8_t maxPriority,
                                 bool isCancelled, bool isEscalated,
-                                bool isStarting, bool isRunning, bool isEnqueued) {
+                                bool isStarting, bool isRunning,
+                                bool isEnqueued, bool wasRunning) {
+#if !TARGET_OS_SIMULATOR
+#if OS_APT_SPI_VERSION >= 20241023
+  uint64_t taskId = task->getTaskId();
+  if (isRunning) {
+    if (SWIFT_RUNTIME_WEAK_CHECK(os_apt_msg_async_task_running_4swift)) {
+      SWIFT_RUNTIME_WEAK_USE(os_apt_msg_async_task_running_4swift(taskId));
+    }
+  } else if (!isRunning && wasRunning) {
+#if OS_APT_SPI_VERSION >= 20250710
+    if (SWIFT_RUNTIME_WEAK_CHECK(os_apt_msg_async_task_stopped_4swift)) {
+      SWIFT_RUNTIME_WEAK_USE(os_apt_msg_async_task_stopped_4swift(taskId));
+    }
+#endif // OS_APT_SPI_VERSION >= 20250710
+  }
+#endif // OS_APT_SPI_VERSION >= 20241023
+#endif // !TARGET_OS_SIMULATOR
   ENSURE_LOGS();
   auto id = os_signpost_id_make_with_pointer(TaskLog, task);
   os_signpost_event_emit(
diff --git a/stdlib/public/Concurrency/TracingStubs.h b/stdlib/public/Concurrency/TracingStubs.h
index 179434e926be7..2c610e6db5cac 100644
--- a/stdlib/public/Concurrency/TracingStubs.h
+++ b/stdlib/public/Concurrency/TracingStubs.h
@@ -56,7 +56,8 @@ inline void task_resume(AsyncTask *task) {}
 
 inline void task_status_changed(AsyncTask *task, uint8_t maxPriority,
                                 bool isCancelled, bool isEscalated,
-                                bool isStarting, bool isRunning, bool isEnqueued) {}
+                                bool isStarting, bool isRunning,
+                                bool isEnqueued, bool wasRunning) {}
 
 inline void task_flags_changed(AsyncTask *task, uint8_t jobPriority,
                                bool isChildTask, bool isFuture,
diff --git a/stdlib/public/Concurrency/UnimplementedExecutor.swift b/stdlib/public/Concurrency/UnimplementedExecutor.swift
new file mode 100644
index 0000000000000..f4a299fc550be
--- /dev/null
+++ b/stdlib/public/Concurrency/UnimplementedExecutor.swift
@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2020 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import Swift
+
+// .. Main Executor ............................................................
+
+@available(StdlibDeploymentTarget 6.2, *)
+public final class UnimplementedMainExecutor: MainExecutor, @unchecked Sendable {
+  public init() {}
+
+  public func run() throws {
+    fatalError("There is no executor implementation active")
+  }
+
+  public func stop() {
+    fatalError("There is no executor implementation active")
+  }
+
+  #if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+  public func enqueue(_ job: UnownedJob) {
+    fatalError("There is no executor implementation active")
+  }
+  #else
+  public func enqueue(_ job: consuming ExecutorJob) {
+    fatalError("There is no executor implementation active")
+  }
+  #endif
+
+  public var isMainExecutor: Bool { true }
+
+  public func checkIsolated() {
+    // Do nothing
+  }
+}
+
+// .. Task Executor ............................................................
+
+@available(StdlibDeploymentTarget 6.2, *)
+public final class UnimplementedTaskExecutor: TaskExecutor, @unchecked Sendable {
+  public init() {}
+
+  #if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+  public func enqueue(_ job: UnownedJob) {
+    fatalError("There is no executor implementation active")
+  }
+  #else
+  public func enqueue(_ job: consuming ExecutorJob) {
+    fatalError("There is no executor implementation active")
+  }
+  #endif
+
+  public var isMainExecutor: Bool { false }
+}
diff --git a/stdlib/public/Cxx/CMakeLists.txt b/stdlib/public/Cxx/CMakeLists.txt
index 05fee6c62d9c5..4d307296aed3d 100644
--- a/stdlib/public/Cxx/CMakeLists.txt
+++ b/stdlib/public/Cxx/CMakeLists.txt
@@ -21,8 +21,9 @@ add_swift_target_library(swiftCxx STATIC NO_LINK_NAME IS_STDLIB IS_SWIFT_ONLY
 
     SWIFT_COMPILE_FLAGS ${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS} ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
     -cxx-interoperability-mode=default
-    -enable-experimental-feature Span
     -enable-experimental-feature BuiltinModule
+    -enable-experimental-feature AllowUnsafeAttribute
+    -enable-experimental-feature Lifetimes
     -strict-memory-safety
     # This module should not pull in the C++ standard library, so we disable it explicitly.
     # For functionality that depends on the C++ stdlib, use C++ stdlib overlay (`swiftstd` module).
@@ -38,6 +39,7 @@ add_swift_target_library(swiftCxx STATIC NO_LINK_NAME IS_STDLIB IS_SWIFT_ONLY
     DEPENDS ${SWIFT_CXX_DEPS}
     MACCATALYST_BUILD_FLAVOR zippered
     INSTALL_IN_COMPONENT compiler
+    INSTALL_BINARY_SWIFTMODULE NON_DARWIN_ONLY
     INSTALL_WITH_SHARED)
 
 add_subdirectory(libstdcxx)
diff --git a/stdlib/public/Cxx/CxxDictionary.swift b/stdlib/public/Cxx/CxxDictionary.swift
index eb975a63de7bc..d78c83dcaa0d9 100644
--- a/stdlib/public/Cxx/CxxDictionary.swift
+++ b/stdlib/public/Cxx/CxxDictionary.swift
@@ -174,10 +174,10 @@ extension CxxDictionary {
   }
 
   @inlinable
-  public mutating func merge<S: Sequence>(
+  public mutating func merge<S: Sequence, E>(
     _ other: __owned S,
-    uniquingKeysWith combine: (Value, Value) throws -> Value
-  ) rethrows where S.Element == (Key, Value) {
+    uniquingKeysWith combine: (Value, Value) throws(E) -> Value
+  ) throws(E) where S.Element == (Key, Value) {
     for (key, value) in other {
       var iter = self.__findMutatingUnsafe(key)
       if iter != self.__endMutatingUnsafe() {
@@ -190,10 +190,10 @@ extension CxxDictionary {
   }
 
   @inlinable
-  public mutating func merge(
+  public mutating func merge<E>(
     _ other: __owned Dictionary<Key, Value>,
-    uniquingKeysWith combine: (Value, Value) throws -> Value
-  ) rethrows where Key: Hashable {
+    uniquingKeysWith combine: (Value, Value) throws(E) -> Value
+  ) throws(E) where Key: Hashable {
     for (key, value) in other {
       var iter = self.__findMutatingUnsafe(key)
       if iter != self.__endMutatingUnsafe() {
@@ -206,10 +206,10 @@ extension CxxDictionary {
   }
 
   @inlinable
-  public mutating func merge(
-    _ other: __owned Self,
-    uniquingKeysWith combine: (Value, Value) throws -> Value
-  ) rethrows {
+  public mutating func merge<T: CxxDictionary, E>(
+    _ other: __owned T,
+    uniquingKeysWith combine: (Value, Value) throws(E) -> Value
+  ) throws(E) where T.Key == Key, T.Value == Value {
     var iterator = other.__beginUnsafe()
     while iterator != other.__endUnsafe() {
       var iter = self.__findMutatingUnsafe(iterator.pointee.first)
@@ -224,32 +224,47 @@ extension CxxDictionary {
   }
 
   @inlinable
-  public __consuming func merging<S: Sequence>(
+  public __consuming func merging<S: Sequence, E>(
     _ other: __owned S,
-    uniquingKeysWith combine: (Value, Value) throws -> Value
-  ) rethrows -> Self where S.Element == (Key, Value) {
+    uniquingKeysWith combine: (Value, Value) throws(E) -> Value
+  ) throws(E) -> Self where S.Element == (Key, Value) {
     var result = self
     try result.merge(other, uniquingKeysWith: combine)
     return result
   }
 
   @inlinable
-  public __consuming func merging(
+  public __consuming func merging<E>(
       _ other: __owned Dictionary<Key, Value>,
-      uniquingKeysWith combine: (Value, Value) throws -> Value
-  ) rethrows -> Self where Key: Hashable {
+      uniquingKeysWith combine: (Value, Value) throws(E) -> Value
+  ) throws(E) -> Self where Key: Hashable {
     var result = self
     try result.merge(other, uniquingKeysWith: combine)
     return result
   }
 
   @inlinable
-  public __consuming func merging(
-    _ other: __owned Self,
-    uniquingKeysWith combine: (Value, Value) throws -> Value
-  ) rethrows -> Self {
+  public __consuming func merging<T: CxxDictionary, E>(
+    _ other: __owned T,
+    uniquingKeysWith combine: (Value, Value) throws(E) -> Value
+  ) throws(E) -> Self where T.Key == Key, T.Value == Value {
     var result = self
     try result.merge(other, uniquingKeysWith: combine)
     return result
   }
 }
+
+extension Dictionary {
+  @inlinable
+  public init(_ dictionary: some CxxDictionary<Key, Value>) {
+    self.init()
+
+    var it = dictionary.__beginUnsafe()
+    let endIterator = dictionary.__endUnsafe()
+    while it != endIterator {
+      self[it.pointee.first] = it.pointee.second
+      it = it.successor()
+    }
+    withExtendedLifetime(dictionary) {}
+  }
+}
diff --git a/stdlib/public/Cxx/CxxSpan.swift b/stdlib/public/Cxx/CxxSpan.swift
index 4064a650f8896..9a9568a59c5a0 100644
--- a/stdlib/public/Cxx/CxxSpan.swift
+++ b/stdlib/public/Cxx/CxxSpan.swift
@@ -12,8 +12,8 @@
 import Builtin
 
 @usableFromInline
-internal func unsafeBitCast<T: ~Escapable, U>(
-   _ x: T, to type: U.Type
+internal func unsafeBitCast<T: ~Escapable & ~Copyable, U>(
+   _ x: consuming T, to type: U.Type
 ) -> U {
   Builtin.reinterpretCast(x)
 }
@@ -66,7 +66,7 @@ public protocol CxxSpan<Element> {
   associatedtype Size: BinaryInteger
 
   init()
-  init(_ unsafePointer : UnsafePointer<Element>, _ count: Size)
+  init(_ unsafePointer: UnsafePointer<Element>!, _ count: Size)
 
   func size() -> Size
   func __dataUnsafe() -> UnsafePointer<Element>?
@@ -74,22 +74,22 @@ public protocol CxxSpan<Element> {
 
 extension CxxSpan {
   /// Creates a C++ span from a Swift UnsafeBufferPointer
-  @inlinable
+  @_alwaysEmitIntoClient
   public init(_ unsafeBufferPointer: UnsafeBufferPointer<Element>) {
     unsafe precondition(unsafeBufferPointer.baseAddress != nil, 
                   "UnsafeBufferPointer should not point to nil")
     unsafe self.init(unsafeBufferPointer.baseAddress!, Size(unsafeBufferPointer.count))
   }
 
-  @inlinable
+  @_alwaysEmitIntoClient
   public init(_ unsafeMutableBufferPointer: UnsafeMutableBufferPointer<Element>) {
     unsafe precondition(unsafeMutableBufferPointer.baseAddress != nil, 
                   "UnsafeMutableBufferPointer should not point to nil")
     unsafe self.init(unsafeMutableBufferPointer.baseAddress!, Size(unsafeMutableBufferPointer.count))
   }
 
-  @available(SwiftStdlib 6.2, *)
-  @inlinable
+  @available(SwiftCompatibilitySpan 5.0, *)
+  @_alwaysEmitIntoClient
   @unsafe
   public init(_ span: Span<Element>) {
     let (p, c) = unsafe unsafeBitCast(span, to: (UnsafeRawPointer?, Int).self)
@@ -99,7 +99,7 @@ extension CxxSpan {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
 extension Span {
   @_alwaysEmitIntoClient
   @unsafe
@@ -115,7 +115,7 @@ extension Span {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
 extension MutableSpan {
   @_alwaysEmitIntoClient
   @unsafe
@@ -136,18 +136,28 @@ public protocol CxxMutableSpan<Element> {
   associatedtype Size: BinaryInteger
 
   init()
-  init(_ unsafeMutablePointer : UnsafeMutablePointer<Element>, _ count: Size)
+  init(_ unsafeMutablePointer: UnsafeMutablePointer<Element>!, _ count: Size)
 
   func size() -> Size
-  func __dataUnsafe() -> UnsafeMutablePointer<Element>
+  func __dataUnsafe() -> UnsafeMutablePointer<Element>?
 }
 
 extension CxxMutableSpan {
   /// Creates a C++ span from a Swift UnsafeMutableBufferPointer
-  @inlinable
+  @_alwaysEmitIntoClient
   public init(_ unsafeMutableBufferPointer: UnsafeMutableBufferPointer<Element>) {
     unsafe precondition(unsafeMutableBufferPointer.baseAddress != nil, 
                   "UnsafeMutableBufferPointer should not point to nil")
     unsafe self.init(unsafeMutableBufferPointer.baseAddress!, Size(unsafeMutableBufferPointer.count))
   }
+
+  @available(SwiftCompatibilitySpan 5.0, *)
+  @_alwaysEmitIntoClient
+  @unsafe
+  public init(_ span: consuming MutableSpan<Element>) {
+    let (p, c) = unsafe unsafeBitCast(span, to: (UnsafeMutableRawPointer?, Int).self)
+    unsafe precondition(p != nil, "Span should not point to nil")
+    let binding = unsafe p!.bindMemory(to: Element.self, capacity: c)
+    unsafe self.init(binding, Size(c))
+  }
 }
diff --git a/stdlib/public/Cxx/CxxVector.swift b/stdlib/public/Cxx/CxxVector.swift
index b226b3a6755a1..2037ed000650e 100644
--- a/stdlib/public/Cxx/CxxVector.swift
+++ b/stdlib/public/Cxx/CxxVector.swift
@@ -50,7 +50,7 @@ extension CxxVector {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
 extension CxxVector {
   public var span: Span<Element> {
     @lifetime(borrow self)
diff --git a/stdlib/public/Cxx/cxxshim/libcxxshim.h b/stdlib/public/Cxx/cxxshim/libcxxshim.h
index 102bc1548faa5..52df8cc647914 100644
--- a/stdlib/public/Cxx/cxxshim/libcxxshim.h
+++ b/stdlib/public/Cxx/cxxshim/libcxxshim.h
@@ -1,2 +1,4 @@
 template <class From, class To>
-To __swift_interopStaticCast(From from) { return static_cast<To>(from); }
\ No newline at end of file
+To _Nonnull __swift_interopStaticCast(From _Nonnull from) {
+  return static_cast<To>(from);
+}
diff --git a/stdlib/public/Cxx/cxxshim/libcxxstdlibshim.h b/stdlib/public/Cxx/cxxshim/libcxxstdlibshim.h
index 90bb57fe315ed..9d2a67ed87c40 100644
--- a/stdlib/public/Cxx/cxxshim/libcxxstdlibshim.h
+++ b/stdlib/public/Cxx/cxxshim/libcxxstdlibshim.h
@@ -20,6 +20,12 @@ inline std::size_t __swift_interopComputeHashOfU32String(const std::u32string &s
   return __swift_interopHashOfU32String()(str);
 }
 
+/// Used for std::wstring conformance to Swift.Hashable
+typedef std::hash<std::wstring> __swift_interopHashOfWString;
+inline std::size_t __swift_interopComputeHashOfWString(const std::wstring &str) {
+  return __swift_interopHashOfWString()(str);
+}
+
 inline std::chrono::seconds __swift_interopMakeChronoSeconds(int64_t seconds) {
   return std::chrono::seconds(seconds);
 }
diff --git a/stdlib/public/Cxx/libstdcxx/libstdcxx.modulemap b/stdlib/public/Cxx/libstdcxx/libstdcxx.modulemap
index 4627ffd22307b..29500f9f905e5 100644
--- a/stdlib/public/Cxx/libstdcxx/libstdcxx.modulemap
+++ b/stdlib/public/Cxx/libstdcxx/libstdcxx.modulemap
@@ -22,6 +22,7 @@ module std {
   header "algorithm"
   header "bitset"
   header "complex"
+  header "cstddef"
   header "deque"
   header "exception"
   header "fstream"
diff --git a/stdlib/public/Cxx/std/CMakeLists.txt b/stdlib/public/Cxx/std/CMakeLists.txt
index e2deb144ad723..4a87a99aa4ac1 100644
--- a/stdlib/public/Cxx/std/CMakeLists.txt
+++ b/stdlib/public/Cxx/std/CMakeLists.txt
@@ -6,9 +6,13 @@ add_custom_command_target(unused_var
     CUSTOM_TARGET_NAME CxxStdlib-apinotes
     COMMAND ${CMAKE_COMMAND} "-E" "make_directory" "${output_dir}"
     COMMAND ${CMAKE_COMMAND} "-E" "copy_if_different" "${CMAKE_CURRENT_SOURCE_DIR}/std.apinotes" "${output_dir}"
+    COMMAND ${CMAKE_COMMAND} "-E" "copy_if_different" "${CMAKE_CURRENT_SOURCE_DIR}/std_span.apinotes" "${output_dir}"
+    COMMAND ${CMAKE_COMMAND} "-E" "copy_if_different" "${CMAKE_CURRENT_SOURCE_DIR}/std_string_view.apinotes" "${output_dir}"
     COMMENT "Copying CxxStdlib API Notes to ${output_dir}"
     OUTPUT "${output_dir}/std.apinotes"
-    DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/std.apinotes")
+    DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/std.apinotes"
+    DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/std_span.apinotes"
+    DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/std_string_view.apinotes")
 
 swift_install_in_component(FILES std.apinotes
     DESTINATION "lib/swift/apinotes"
@@ -19,15 +23,6 @@ add_dependencies(sdk-overlay CxxStdlib-apinotes)
 add_dependencies(compiler CxxStdlib-apinotes)
 
 
-# Swift compiler currently assumes that the Darwin overlay is a dependency of
-# CxxStdlib, and fails to build CxxStdlib if Darwin.swiftmodule in build dir
-# is built with a different (older) version of the compiler. To workaround this,
-# declare the Darwin overlay as a dependency of CxxStdlib.
-set(swift_cxxstdlib_darwin_dependencies)
-if(SWIFT_BUILD_STDLIB AND SWIFT_BUILD_SDK_OVERLAY)
-  set(swift_cxxstdlib_darwin_dependencies Darwin)
-endif()
-
 set(swift_cxxstdlib_dependencies)
 if(NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT)
   set(swift_cxxstdlib_dependencies _Builtin_float)
@@ -44,12 +39,6 @@ add_swift_target_library(swiftCxxStdlib STATIC NO_LINK_NAME IS_STDLIB IS_SWIFT_O
     String.swift
 
     SWIFT_MODULE_DEPENDS Cxx ${swift_cxxstdlib_dependencies}
-    SWIFT_MODULE_DEPENDS_IOS ${swift_cxxstdlib_darwin_dependencies}
-    SWIFT_MODULE_DEPENDS_OSX ${swift_cxxstdlib_darwin_dependencies}
-    SWIFT_MODULE_DEPENDS_TVOS ${swift_cxxstdlib_darwin_dependencies}
-    SWIFT_MODULE_DEPENDS_WATCHOS ${swift_cxxstdlib_darwin_dependencies}
-    SWIFT_MODULE_DEPENDS_XROS ${swift_cxxstdlib_darwin_dependencies}
-    SWIFT_MODULE_DEPENDS_MACCATALYST ${swift_cxxstdlib_darwin_dependencies}
     SWIFT_MODULE_DEPENDS_ANDROID Android
 
     SWIFT_COMPILE_FLAGS ${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS} ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
@@ -59,7 +48,8 @@ add_swift_target_library(swiftCxxStdlib STATIC NO_LINK_NAME IS_STDLIB IS_SWIFT_O
     # This flag is unnecessary when building with newer compilers that allow
     # using C++ symbols in resilient overlays (see f4204568).
     -enable-experimental-feature AssumeResilientCxxTypes
-
+    -enable-experimental-feature Lifetimes
+    -enable-experimental-feature AllowUnsafeAttribute
     -strict-memory-safety
 
     # The varying modularization of the C++ standard library on different
@@ -77,8 +67,9 @@ add_swift_target_library(swiftCxxStdlib STATIC NO_LINK_NAME IS_STDLIB IS_SWIFT_O
     DEPLOYMENT_VERSION_XROS ${COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_XROS}
 
     LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
-    TARGET_SDKS ALL_APPLE_PLATFORMS LINUX WINDOWS ANDROID
+    TARGET_SDKS ALL_APPLE_PLATFORMS LINUX LINUX_STATIC WINDOWS ANDROID FREEBSD
     MACCATALYST_BUILD_FLAVOR zippered
     INSTALL_IN_COMPONENT compiler
+    INSTALL_BINARY_SWIFTMODULE NON_DARWIN_ONLY
     INSTALL_WITH_SHARED
     DEPENDS libstdcxx-modulemap libcxxshim_modulemap CxxStdlib-apinotes)
diff --git a/stdlib/public/Cxx/std/String.swift b/stdlib/public/Cxx/std/String.swift
index 49665dd270f0f..efef887eeee8e 100644
--- a/stdlib/public/Cxx/std/String.swift
+++ b/stdlib/public/Cxx/std/String.swift
@@ -21,32 +21,47 @@ extension std.string {
   ///   Swift string.
   @_alwaysEmitIntoClient
   public init(_ string: String) {
-    unsafe self = unsafe string.withCString(encodedAs: UTF8.self) { buffer in
-#if os(Windows)
-      // Use the 2 parameter constructor.
-      // The MSVC standard library has a enable_if template guard
-      // on the 3 parameter constructor, and thus it's not imported into Swift.
-      std.string(buffer, string.utf8.count)
-#else
+    self = unsafe string.withCString(encodedAs: UTF8.self) { buffer in
+      // MSVC STL has a enable_if template guard on the 3-parameter constructor,
+      // and thus it's not imported into Swift.
+      // libc++ provides both 2-parameter and 3-parameter constructors.
+      // libstdc++ only provides the 3-parameter constructor.
+
+      // Note that we might be compiling with libc++ on Linux, even if it's not
+      // the default stdlib on a particular distro. 
+#if os(Linux)
       unsafe std.string(buffer, string.utf8.count, .init())
+#else
+      unsafe std.string(buffer, string.utf8.count)
 #endif
     }
   }
 
+
   @_alwaysEmitIntoClient
-  public init(_ string: UnsafePointer<CChar>?) {
-    if let str = unsafe string {
-#if os(Windows)
-      // Use the 2 parameter constructor.
-      // The MSVC standard library has a enable_if template guard
-      // on the 3 parameter constructor, and thus it's not imported into Swift.
-      self.init(str, UTF8._nullCodeUnitOffset(in: str))
+  @available(*, unavailable, message: "initializing std::string with an optional String is not supported; unwrap the optional value before passing it to std.string()")
+  public init(_ string: String?) {
+      fatalError("This initializer is unavailable and should never be called.")
+  }
+
+  @_alwaysEmitIntoClient
+  public init(_ string: UnsafePointer<CChar>) {
+#if os(Linux)
+    unsafe self.init(string, UTF8._nullCodeUnitOffset(in: string), .init())
 #else
-      unsafe self.init(str, UTF8._nullCodeUnitOffset(in: str), .init())
+    unsafe self.init(string, UTF8._nullCodeUnitOffset(in: string))
 #endif
-    } else {
+  }
+
+  @_alwaysEmitIntoClient
+  @_disfavoredOverload
+  @available(*, deprecated, message: "unwrap the optional value and use init(_ string: UnsafePointer<CChar>) instead")
+  public init(_ string: UnsafePointer<CChar>?) {
+    guard let str = unsafe string else {
       self.init()
+      return
     }
+    unsafe self.init(str)
   }
 }
 
@@ -80,6 +95,30 @@ extension std.u32string {
   }
 }
 
+extension std.wstring {
+  /// Creates a C++ wide character string having the same content as the given 
+  /// Swift string.
+  ///
+  /// Note that the definition of a wide character differs across platforms:
+  /// it is UTF-16 on Windows but UTF-32 on other platforms.
+  ///
+  /// - Complexity: O(*n*), where *n* is the number of wide characters in the
+  ///   Swift string.
+  @_alwaysEmitIntoClient
+  public init(_ string: String) {
+    self.init()
+#if os(Windows)
+    for char in string.utf16 {
+      self.push_back(char)
+    }
+#else
+    for char in string.unicodeScalars {
+      self.push_back(char)
+    }
+#endif
+  }
+}
+
 // MARK: Initializing C++ string from a Swift String literal
 
 extension std.string: ExpressibleByStringLiteral,
@@ -109,6 +148,15 @@ extension std.u32string: ExpressibleByStringLiteral,
   }
 }
 
+extension std.wstring: ExpressibleByStringLiteral,
+  ExpressibleByStringInterpolation {
+
+  @_alwaysEmitIntoClient
+  public init(stringLiteral value: String) {
+    self.init(value)
+  }
+}
+
 // MARK: Concatenating and comparing C++ strings
 
 extension std.string: Equatable, Comparable {
@@ -198,6 +246,35 @@ extension std.u32string: Equatable, Comparable {
   }
 }
 
+extension std.wstring: Equatable, Comparable {
+  @_alwaysEmitIntoClient
+  public static func ==(lhs: std.wstring, rhs: std.wstring) -> Bool {
+    return lhs.compare(rhs) == 0
+  }
+
+  @_alwaysEmitIntoClient
+  public static func <(lhs: std.wstring, rhs: std.wstring) -> Bool {
+    return lhs.compare(rhs) < 0
+  }
+
+  @_alwaysEmitIntoClient
+  public static func +=(lhs: inout std.wstring, rhs: std.wstring) {
+    lhs.append(rhs)
+  }
+
+  @_alwaysEmitIntoClient
+  public mutating func append(_ other: std.wstring) {
+    unsafe __appendUnsafe(other) // ignore the returned pointer
+  }
+
+  @_alwaysEmitIntoClient
+  public static func +(lhs: std.wstring, rhs: std.wstring) -> std.wstring {
+    var copy = lhs
+    copy += rhs
+    return copy
+  }
+}
+
 // MARK: Hashing C++ strings
 
 extension std.string: Hashable {
@@ -227,6 +304,15 @@ extension std.u32string: Hashable {
   }
 }
 
+extension std.wstring: Hashable {
+  @_alwaysEmitIntoClient
+  public func hash(into hasher: inout Hasher) {
+    // Call std::hash<std::wstring>::operator()
+    let cxxHash = __swift_interopComputeHashOfWString(self)
+    hasher.combine(cxxHash)
+  }
+}
+
 // MARK: Getting a Swift description of a C++ string
 
 extension std.string: CustomDebugStringConvertible {
@@ -250,6 +336,13 @@ extension std.u32string: CustomDebugStringConvertible {
   }
 }
 
+extension std.wstring: CustomDebugStringConvertible {
+  @_alwaysEmitIntoClient
+  public var debugDescription: String {
+    return "std.wstring(\(String(self)))"
+  }
+}
+
 extension std.string: CustomStringConvertible {
   @_alwaysEmitIntoClient
   public var description: String {
@@ -271,6 +364,13 @@ extension std.u32string: CustomStringConvertible {
   }
 }
 
+extension std.wstring: CustomStringConvertible {
+  @_alwaysEmitIntoClient
+  public var description: String {
+    return String(self)
+  }
+}
+
 // MARK: Initializing Swift String from a C++ string
 
 extension String {
@@ -327,6 +427,36 @@ extension String {
     }
     withExtendedLifetime(cxxU32String) {}
   }
+
+  /// Creates a String having the same content as the given C++ wide character 
+  /// string.
+  ///
+  /// Note that the definition of a wide character differs across platforms:
+  /// it is UTF-16 on Windows but UTF-32 on other platforms.
+  ///
+  /// If `cxxString` contains ill-formed UTF code unit sequences, this
+  /// initializer replaces them with the Unicode replacement character
+  /// (`"\u{FFFD}"`).
+  ///
+  /// - Complexity: O(*n*), where *n* is the number of wide characters in the
+  ///   C++ string.
+  @_alwaysEmitIntoClient
+  public init(_ cxxWString: std.wstring) {
+#if os(Windows)
+    let buffer = unsafe UnsafeBufferPointer<UInt16>(
+      start: cxxWString.__dataUnsafe(),
+      count: cxxWString.size())
+    self = unsafe String(decoding: buffer, as: UTF16.self)
+#else
+    let buffer = unsafe UnsafeBufferPointer<Unicode.Scalar>(
+      start: cxxWString.__dataUnsafe(),
+      count: cxxWString.size())
+    self = unsafe buffer.withMemoryRebound(to: UInt32.self) {
+      unsafe String(decoding: $0, as: UTF32.self)
+    }
+#endif
+    withExtendedLifetime(cxxWString) {}
+  }
 }
 
 // MARK: Initializing Swift String from a C++ string_view
@@ -388,4 +518,96 @@ extension String {
     }
     unsafe withExtendedLifetime(cxxU32StringView) {}
   }
+
+  @_alwaysEmitIntoClient
+  public init(_ cxxWStringView: std.wstring_view) {
+#if os(Windows)
+    let buffer = unsafe UnsafeBufferPointer<UInt16>(
+      start: cxxWStringView.__dataUnsafe(),
+      count: cxxWStringView.size())
+    self = unsafe String(decoding: buffer, as: UTF16.self)
+#else
+    let buffer = unsafe UnsafeBufferPointer<Unicode.Scalar>(
+      start: cxxWStringView.__dataUnsafe(),
+      count: cxxWStringView.size())
+    self = unsafe buffer.withMemoryRebound(to: UInt32.self) {
+      unsafe String(decoding: $0, as: UTF32.self)
+    }
+#endif
+    unsafe withExtendedLifetime(cxxWStringView) {}
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+extension std.string {
+  public var span: Span<CChar> {
+    @_lifetime(borrow self)
+    @_alwaysEmitIntoClient
+    borrowing get {
+      let buffer = unsafe UnsafeBufferPointer(start: self.__dataUnsafe(), count: Int(self.size()))
+      let span = unsafe Span(_unsafeElements: buffer)
+      return unsafe _cxxOverrideLifetime(span, borrowing: self)
+    }
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+extension std.string {
+  public var utf8Span: UTF8Span? {
+    @_lifetime(borrow self)
+    @_alwaysEmitIntoClient
+    borrowing get {
+      let buffer = unsafe UnsafeBufferPointer(start: self.__dataUnsafe(), count: Int(self.size()))
+      let rawBuffer = UnsafeRawBufferPointer(buffer)
+      let bufferWithFixedType = unsafe rawBuffer.assumingMemoryBound(to: UInt8.self)
+      let span = unsafe Span(_unsafeElements: bufferWithFixedType)
+      let spanWithFixedLifetime = unsafe _cxxOverrideLifetime(span, borrowing: self)
+      return try? UTF8Span(validating: spanWithFixedLifetime)
+    }
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+extension std.u16string {
+  public var span: Span<UInt16> {
+    @_lifetime(borrow self)
+    @_alwaysEmitIntoClient
+    borrowing get {
+      let buffer = unsafe UnsafeBufferPointer(start: self.__dataUnsafe(), count: Int(self.size()))
+      let rawBuffer = UnsafeRawBufferPointer(buffer)
+      let bufferWithFixedType = unsafe rawBuffer.assumingMemoryBound(to: UInt16.self)
+      let span = unsafe Span(_unsafeElements: bufferWithFixedType)
+      return unsafe _cxxOverrideLifetime(span, borrowing: self)
+    }
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+extension std.u32string {
+  public var span: Span<UInt32> {
+    @_lifetime(borrow self)
+    @_alwaysEmitIntoClient
+    borrowing get {
+      let buffer = unsafe UnsafeBufferPointer(start: self.__dataUnsafe(), count: Int(self.size()))
+      let rawBuffer = UnsafeRawBufferPointer(buffer)
+      let bufferWithFixedType = unsafe rawBuffer.assumingMemoryBound(to: UInt32.self)
+      let span = unsafe Span(_unsafeElements: bufferWithFixedType)
+      return unsafe _cxxOverrideLifetime(span, borrowing: self)
+    }
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+extension std.wstring {
+  public var span: Span<CWideChar> {
+    @_lifetime(borrow self)
+    @_alwaysEmitIntoClient
+    borrowing get {
+      let buffer = unsafe UnsafeBufferPointer(start: self.__dataUnsafe(), count: Int(self.size()))
+      let rawBuffer = UnsafeRawBufferPointer(buffer)
+      let bufferWithFixedType = unsafe rawBuffer.assumingMemoryBound(to: CWideChar.self)
+      let span = unsafe Span(_unsafeElements: bufferWithFixedType)
+      return unsafe _cxxOverrideLifetime(span, borrowing: self)
+    }
+  }
 }
diff --git a/stdlib/public/Cxx/std/std.apinotes b/stdlib/public/Cxx/std/std.apinotes
index eab6f835c9c26..5b15211f5e717 100644
--- a/stdlib/public/Cxx/std/std.apinotes
+++ b/stdlib/public/Cxx/std/std.apinotes
@@ -17,3 +17,20 @@ Namespaces:
     Methods:
     - Name: data
       SwiftName: __dataUnsafe()
+    - Name: size
+      SwiftSafety: safe
+    - Name: size_bytes
+      SwiftSafety: safe
+    - Name: empty
+      SwiftSafety: safe
+  - Name: basic_string_view
+    Methods:
+    - Name: size
+      SwiftSafety: safe
+    - Name: max_size
+      SwiftSafety: safe
+    - Name: length
+      SwiftSafety: safe
+    - Name: empty
+      SwiftSafety: safe
+ 
\ No newline at end of file
diff --git a/stdlib/public/Cxx/std/std_span.apinotes b/stdlib/public/Cxx/std/std_span.apinotes
new file mode 100644
index 0000000000000..d813f0fe784f2
--- /dev/null
+++ b/stdlib/public/Cxx/std/std_span.apinotes
@@ -0,0 +1,14 @@
+Name: std_span
+Namespaces:
+- Name: std
+  Tags:
+  - Name: span
+    Methods:
+    - Name: data
+      SwiftName: __dataUnsafe()
+    - Name: size
+      SwiftSafety: safe
+    - Name: size_bytes
+      SwiftSafety: safe
+    - Name: empty
+      SwiftSafety: safe
diff --git a/stdlib/public/Cxx/std/std_string_view.apinotes b/stdlib/public/Cxx/std/std_string_view.apinotes
new file mode 100644
index 0000000000000..ca5d034c32ee6
--- /dev/null
+++ b/stdlib/public/Cxx/std/std_string_view.apinotes
@@ -0,0 +1,14 @@
+Name: std_string_view
+Namespaces:
+- Name: std
+  Tags:
+  - Name: basic_string_view
+    Methods:
+    - Name: size
+      SwiftSafety: safe
+    - Name: max_size
+      SwiftSafety: safe
+    - Name: length
+      SwiftSafety: safe
+    - Name: empty
+      SwiftSafety: safe
diff --git a/stdlib/public/Differentiation/ArrayDifferentiation.swift b/stdlib/public/Differentiation/ArrayDifferentiation.swift
index 0378060a63d03..36431d2080d8d 100644
--- a/stdlib/public/Differentiation/ArrayDifferentiation.swift
+++ b/stdlib/public/Differentiation/ArrayDifferentiation.swift
@@ -157,7 +157,7 @@ where Element: AdditiveArithmetic & Differentiable {
     rhs: Array.DifferentiableView
   ) -> Array.DifferentiableView {
     if lhs.base.count == 0 {
-      return rhs
+      return Array.DifferentiableView(rhs.base.map { .zero - $0 })
     }
     if rhs.base.count == 0 {
       return lhs
@@ -369,8 +369,11 @@ extension Array where Element: Differentiable {
     value: [Result],
     pullback: (Array<Result>.TangentVector) -> Array.TangentVector
   ) {
+    let count = self.count
     var values: [Result] = []
     var pullbacks: [(Result.TangentVector) -> Element.TangentVector] = []
+    values.reserveCapacity(count)
+    pullbacks.reserveCapacity(count)
     for x in self {
       let (y, pb) = valueWithPullback(at: x, of: body)
       values.append(y)
diff --git a/stdlib/public/Differentiation/CMakeLists.txt b/stdlib/public/Differentiation/CMakeLists.txt
index 16a296bbbe772..f7149eacb0a8e 100644
--- a/stdlib/public/Differentiation/CMakeLists.txt
+++ b/stdlib/public/Differentiation/CMakeLists.txt
@@ -16,12 +16,6 @@ else()
 set(swiftDifferentiationSIMDFiles)
 endif()
 
-if(SWIFT_BUILD_SDK_OVERLAY)
-set(swiftDifferentiationDarwinDependencies Darwin)
-else()
-set(swiftDifferentiationDarwinDependencies)
-endif()
-
 add_swift_target_library(swift_Differentiation ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   Differentiable.swift
   DifferentialOperators.swift
@@ -37,11 +31,6 @@ add_swift_target_library(swift_Differentiation ${SWIFT_STDLIB_LIBRARY_BUILD_TYPE
     TgmathDerivatives.swift.gyb
     ${swiftDifferentiationSIMDFiles}
 
-  SWIFT_MODULE_DEPENDS_OSX ${swiftDifferentiationDarwinDependencies}
-  SWIFT_MODULE_DEPENDS_IOS ${swiftDifferentiationDarwinDependencies}
-  SWIFT_MODULE_DEPENDS_TVOS ${swiftDifferentiationDarwinDependencies}
-  SWIFT_MODULE_DEPENDS_WATCHOS ${swiftDifferentiationDarwinDependencies}
-  SWIFT_MODULE_DEPENDS_XROS ${swiftDifferentiationDarwinDependencies}
   SWIFT_MODULE_DEPENDS_ANDROID Android
   SWIFT_MODULE_DEPENDS_LINUX Glibc
   SWIFT_MODULE_DEPENDS_LINUX_STATIC Musl
diff --git a/stdlib/public/Differentiation/SIMDDifferentiation.swift.gyb b/stdlib/public/Differentiation/SIMDDifferentiation.swift.gyb
index a1e10887ee17f..e1da73241ab91 100644
--- a/stdlib/public/Differentiation/SIMDDifferentiation.swift.gyb
+++ b/stdlib/public/Differentiation/SIMDDifferentiation.swift.gyb
@@ -405,9 +405,6 @@ where
   }
 }
 
-// FIXME(TF-1103): Derivative registration does not yet support
-// `@_alwaysEmitIntoClient` original functions like `SIMD.sum()`.
-/*
 extension SIMD
 where
   Self: Differentiable,
@@ -417,6 +414,7 @@ where
   TangentVector == Self
 {
   @inlinable
+  @_alwaysEmitIntoClient
   @derivative(of: sum)
   func _vjpSum() -> (
     value: Scalar, pullback: (Scalar.TangentVector) -> TangentVector
@@ -425,6 +423,7 @@ where
   }
 
   @inlinable
+  @_alwaysEmitIntoClient
   @derivative(of: sum)
   func _jvpSum() -> (
     value: Scalar, differential: (TangentVector) -> Scalar.TangentVector
@@ -432,7 +431,6 @@ where
     return (sum(), { v in Scalar.TangentVector(v.sum()) })
   }
 }
-*/
 
 extension SIMD
 where
@@ -457,3 +455,27 @@ where
     return (Self(repeating: value), { v in Self(repeating: v) })
   }
 }
+
+%for (Scalar, bits) in [('Float',32), ('Double',64)]:
+% for n in vectorscalarCounts:
+extension SIMD${n} where Scalar == ${Scalar} {
+  @inlinable
+  @_alwaysEmitIntoClient
+  @derivative(of: init(repeating:))
+  static func _vjpInit(repeating value: Scalar)
+    -> (value: Self, pullback: (TangentVector) -> Scalar.TangentVector)
+  {
+    return (Self(repeating: value), { v in v.sum() })
+  }
+
+  @inlinable
+  @_alwaysEmitIntoClient
+  @derivative(of: init(repeating:))
+  static func _jvpInit(repeating value: Scalar)
+    -> (value: Self, differential: (Scalar.TangentVector) -> TangentVector)
+  {
+    return (Self(repeating: value), { v in Self(repeating: v) })
+  }
+}
+% end
+%end
diff --git a/stdlib/public/Distributed/CMakeLists.txt b/stdlib/public/Distributed/CMakeLists.txt
index ae3f0fdad123a..9cef1492417c0 100644
--- a/stdlib/public/Distributed/CMakeLists.txt
+++ b/stdlib/public/Distributed/CMakeLists.txt
@@ -10,17 +10,22 @@
 #
 #===----------------------------------------------------------------------===#
 
-if(SWIFT_BUILD_SDK_OVERLAY)
-set(swift_distributed_darwin_dependencies Darwin)
-else()
 set(swift_distributed_darwin_dependencies)
+
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  # This library imports Darwin from the SDK, which re-exports
+  # _Builtin_float which is part of this build.
+  list(APPEND swift_distributed_darwin_dependencies _Builtin_float)
 endif()
 
 set(swift_distributed_link_libraries
   swiftCore)
 
 
-add_swift_target_library(swiftDistributed ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB IMPORTS_NON_OSSA 
+add_swift_target_library(swiftDistributed ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   DistributedActor.cpp
   DistributedActor.swift
   DistributedActorSystem.swift
@@ -52,6 +57,7 @@ add_swift_target_library(swiftDistributed ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS
   SWIFT_COMPILE_FLAGS
     ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
     -parse-stdlib
+    -enable-experimental-feature AllowUnsafeAttribute
     -strict-memory-safety
 
   LINK_FLAGS
diff --git a/stdlib/public/Distributed/DistributedActor.cpp b/stdlib/public/Distributed/DistributedActor.cpp
index 83a30738c76e9..8596288a714a6 100644
--- a/stdlib/public/Distributed/DistributedActor.cpp
+++ b/stdlib/public/Distributed/DistributedActor.cpp
@@ -17,9 +17,9 @@
 #include "swift/ABI/Actor.h"
 #include "swift/ABI/Metadata.h"
 #include "swift/ABI/Task.h"
+#include "swift/Basic/Casting.h"
 #include "swift/Runtime/AccessibleFunction.h"
 #include "swift/Runtime/Concurrency.h"
-#include "swift/Runtime/STLCompatibility.h"
 
 using namespace swift;
 
@@ -103,7 +103,7 @@ static void swift_distributed_execute_target_resume(
     SWIFT_CONTEXT SwiftError *error) {
   auto parentCtx = context->Parent;
   auto resumeInParent =
-      std::bit_cast<TargetExecutorSignature::ContinuationType *>(
+      function_cast<TargetExecutorSignature::ContinuationType *>(
           parentCtx->ResumeParent);
   swift_task_dealloc(context);
   // See `swift_distributed_execute_target` - `parentCtx` in this case
@@ -132,7 +132,7 @@ void swift_distributed_execute_target(
     SwiftError *error =
         swift_distributed_makeDistributedTargetAccessorNotFoundError();
     auto resumeInParent =
-        std::bit_cast<TargetExecutorSignature::ContinuationType *>(
+        function_cast<TargetExecutorSignature::ContinuationType *>(
             callerContext->ResumeParent);
     resumeInParent(callerContext, error);
     return;
@@ -150,7 +150,7 @@ void swift_distributed_execute_target(
       swift_task_alloc(asyncFnPtr->ExpectedContextSize));
 
   calleeContext->Parent = callerContext;
-  calleeContext->ResumeParent = std::bit_cast<TaskContinuationFunction *>(
+  calleeContext->ResumeParent = function_cast<TaskContinuationFunction *>(
       &swift_distributed_execute_target_resume);
 
   accessorEntry(calleeContext, argumentDecoder, argumentTypes, resultBuffer,
diff --git a/stdlib/public/Distributed/DistributedActorSystem.swift b/stdlib/public/Distributed/DistributedActorSystem.swift
index f6f30fd50d3dd..d7067090e5d8d 100644
--- a/stdlib/public/Distributed/DistributedActorSystem.swift
+++ b/stdlib/public/Distributed/DistributedActorSystem.swift
@@ -549,7 +549,7 @@ extension DistributedActorSystem {
         errorCode: .typeDeserializationFailure)
     }
 
-    guard let resultBuffer = _openExistential(returnTypeFromTypeInfo, do: unsafe doAllocateReturnTypeBuffer) else {
+    guard let resultBuffer = unsafe _openExistential(returnTypeFromTypeInfo, do: doAllocateReturnTypeBuffer) else {
       throw ExecuteDistributedTargetError(
         message: "Failed to allocate buffer for distributed target return type",
         errorCode: .typeDeserializationFailure)
diff --git a/stdlib/public/Distributed/DistributedAssertions.swift b/stdlib/public/Distributed/DistributedAssertions.swift
index 881741904c81d..a48dc9028c5e4 100644
--- a/stdlib/public/Distributed/DistributedAssertions.swift
+++ b/stdlib/public/Distributed/DistributedAssertions.swift
@@ -30,10 +30,10 @@ extension DistributedActor {
   /// * In `-O` builds (the default for Xcode's Release configuration), stops
   ///   program execution.
   ///
-  /// - Note: This check is performed against the actor's serial executor,
-  ///   meaning that / if another actor uses the same serial executor--by using
+  /// - Note: Because this check is performed against the actor's serial executor,
+  ///   if another actor uses the same serial executor--by using
   ///   that actor's serial executor as its own ``Actor/unownedExecutor``--this
-  ///   check will succeed , as from a concurrency safety perspective, the
+  ///   check will succeed.  From a concurrency safety perspective, the
   ///   serial executor guarantees mutual exclusion of those two actors.
   ///
   /// - Parameters:
diff --git a/stdlib/public/Distributed/LocalTestingDistributedActorSystem.swift b/stdlib/public/Distributed/LocalTestingDistributedActorSystem.swift
index 6dfa8138b2480..a6436a891eb8f 100644
--- a/stdlib/public/Distributed/LocalTestingDistributedActorSystem.swift
+++ b/stdlib/public/Distributed/LocalTestingDistributedActorSystem.swift
@@ -12,8 +12,8 @@
 
 import Swift
 
-#if canImport(Darwin)
-import Darwin
+#if canImport(Darwin.os.lock)
+import Darwin.os.lock
 #elseif canImport(Glibc)
 import Glibc
 #elseif canImport(Musl)
@@ -255,12 +255,12 @@ fileprivate class _Lock {
     unsafe self.underlying = UnsafeMutablePointer.allocate(capacity: 1)
     unsafe self.underlying.initialize(to: os_unfair_lock())
     #elseif os(Windows)
-    self.underlying = UnsafeMutablePointer.allocate(capacity: 1)
-    InitializeSRWLock(self.underlying)
+    unsafe self.underlying = UnsafeMutablePointer.allocate(capacity: 1)
+    unsafe InitializeSRWLock(self.underlying)
     #elseif os(WASI)
     // WASI environment has only a single thread
     #else
-    self.underlying = UnsafeMutablePointer.allocate(capacity: 1)
+    unsafe self.underlying = UnsafeMutablePointer.allocate(capacity: 1)
     guard unsafe pthread_mutex_init(self.underlying, nil) == 0 else {
       fatalError("pthread_mutex_init failed")
     }
@@ -292,7 +292,7 @@ fileprivate class _Lock {
     #if os(iOS) || os(macOS) || os(tvOS) || os(watchOS) || os(visionOS)
     unsafe os_unfair_lock_lock(self.underlying)
     #elseif os(Windows)
-    AcquireSRWLockExclusive(self.underlying)
+    unsafe AcquireSRWLockExclusive(self.underlying)
     #elseif os(WASI)
     // WASI environment has only a single thread
     #else
@@ -305,7 +305,7 @@ fileprivate class _Lock {
       #if os(iOS) || os(macOS) || os(tvOS) || os(watchOS) || os(visionOS)
       unsafe os_unfair_lock_unlock(self.underlying)    
       #elseif os(Windows)
-      ReleaseSRWLockExclusive(self.underlying)
+      unsafe ReleaseSRWLockExclusive(self.underlying)
       #elseif os(WASI)
       // WASI environment has only a single thread
       #else
diff --git a/stdlib/public/Observation/Sources/Observation/CMakeLists.txt b/stdlib/public/Observation/Sources/Observation/CMakeLists.txt
index 7872598bd64d9..c1124141d1ad5 100644
--- a/stdlib/public/Observation/Sources/Observation/CMakeLists.txt
+++ b/stdlib/public/Observation/Sources/Observation/CMakeLists.txt
@@ -13,11 +13,11 @@
 list(APPEND swift_runtime_library_compile_flags -I${SWIFT_SOURCE_DIR}/stdlib/include -I${SWIFT_SOURCE_DIR}/include)
 
 add_swift_target_library(swiftObservation ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
-  Locking.cpp
   Locking.swift
   Observable.swift
   ObservationRegistrar.swift
   ObservationTracking.swift
+  Observations.swift
   ThreadLocal.cpp
   ThreadLocal.swift
 
diff --git a/stdlib/public/Observation/Sources/Observation/Locking.cpp b/stdlib/public/Observation/Sources/Observation/Locking.cpp
deleted file mode 100644
index 520fc07d17e92..0000000000000
--- a/stdlib/public/Observation/Sources/Observation/Locking.cpp
+++ /dev/null
@@ -1,42 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2023 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-#include "swift/Runtime/Config.h"
-#include "swift/Threading/Mutex.h"
-
-using namespace swift;
-
-extern "C" SWIFT_CC(swift) __attribute__((visibility("hidden")))
-size_t _swift_observation_lock_size() {
-  size_t bytes = sizeof(Mutex);
-
-  if (bytes < 1) {
-    return 1;
-  }
-
-  return bytes;
-}
-
-extern "C" SWIFT_CC(swift) __attribute__((visibility("hidden")))
-void _swift_observation_lock_init(Mutex &lock) {
-  new (&lock) Mutex();
-}
-
-extern "C" SWIFT_CC(swift) __attribute__((visibility("hidden")))
-void _swift_observation_lock_lock(Mutex &lock) {
-  lock.lock();
-}
-
-extern "C" SWIFT_CC(swift) __attribute__((visibility("hidden")))
-void _swift_observation_lock_unlock(Mutex &lock) {
-  lock.unlock();
-}
diff --git a/stdlib/public/Observation/Sources/Observation/Locking.swift b/stdlib/public/Observation/Sources/Observation/Locking.swift
index 3b7f380f135ed..c92c88de6cc2c 100644
--- a/stdlib/public/Observation/Sources/Observation/Locking.swift
+++ b/stdlib/public/Observation/Sources/Observation/Locking.swift
@@ -9,52 +9,173 @@
 //
 //===----------------------------------------------------------------------===//
 
+// NOTE: this can't use Synchronization because it is deployed before that was
+// introduced and availability wont let it be hidden behind an internal type.
+// The Swift internal runtime locking cannot be used since that emits dependent
+// symbols that are not provided by this library - so instead it has to re-implement
+// all of this on its own... 
 
-@_silgen_name("_swift_observation_lock_size")
-func _lockSize() -> Int
+#if canImport(Darwin.os.lock)
+import Darwin.os.lock
+#elseif canImport(Glibc)
+import Glibc
+#elseif canImport(Musl)
+import Musl
+#elseif canImport(WinSDK)
+import WinSDK
+#elseif canImport(Bionic)
+import Bionic
+#elseif arch(wasm32)
+#else
+#error("Unsupported platform")
+#endif
 
-@_silgen_name("_swift_observation_lock_init")
-func _lockInit(_: UnsafeRawPointer)
+internal struct Lock {
+  #if canImport(Darwin.os.lock)
+  typealias Primitive = os_unfair_lock
+  #elseif canImport(Glibc) || canImport(Musl) || canImport(Bionic)
+  #if os(FreeBSD) || os(OpenBSD)
+  // BSD libc does not annotate the nullability of pthread APIs.
+  // We should replace this with the appropriate API note in the platform
+  // overlay.
+  // https://github.com/swiftlang/swift/issues/81407
+  typealias Primitive = pthread_mutex_t?
+  #else
+  typealias Primitive = pthread_mutex_t
+  #endif
+  #elseif canImport(WinSDK)
+  typealias Primitive = SRWLOCK
+  #elseif arch(wasm32)
+  typealias Primitive = Int
+  #else
+  #error("Unsupported platform")
+  #endif
 
-@_silgen_name("_swift_observation_lock_lock")
-func _lockLock(_: UnsafeRawPointer)
+  typealias PlatformLock = UnsafeMutablePointer<Primitive>
+  let platformLock: PlatformLock
 
-@_silgen_name("_swift_observation_lock_unlock")
-func _lockUnlock(_: UnsafeRawPointer)
+  private init(_ platformLock: PlatformLock) {
+    self.platformLock = platformLock
+  }
 
-@available(SwiftStdlib 5.9, *)
-internal struct _ManagedCriticalState<State> {
-  final private class LockedBuffer: ManagedBuffer<State, UnsafeRawPointer> { }
+  fileprivate static func initialize(_ platformLock: PlatformLock) {
+    #if canImport(Darwin.os.lock)
+    platformLock.initialize(to: os_unfair_lock())
+    #elseif canImport(Glibc) || canImport(Musl) || canImport(Bionic)
+    let result = pthread_mutex_init(platformLock, nil)
+    precondition(result == 0, "pthread_mutex_init failed")
+    #elseif canImport(WinSDK)
+    InitializeSRWLock(platformLock)
+    #elseif arch(wasm32)
+    platformLock.initialize(to: 0)
+    #else
+    #error("Unsupported platform")
+    #endif
+  }
+
+  fileprivate static func deinitialize(_ platformLock: PlatformLock) {
+    #if canImport(Glibc) || canImport(Musl) || canImport(Bionic)
+    let result = pthread_mutex_destroy(platformLock)
+    precondition(result == 0, "pthread_mutex_destroy failed")
+    #endif
+    platformLock.deinitialize(count: 1)
+  }
+
+  fileprivate static func lock(_ platformLock: PlatformLock) {
+    #if canImport(Darwin.os.lock)
+    os_unfair_lock_lock(platformLock)
+    #elseif canImport(Glibc) || canImport(Musl) || canImport(Bionic)
+    pthread_mutex_lock(platformLock)
+    #elseif canImport(WinSDK)
+    AcquireSRWLockExclusive(platformLock)
+    #elseif arch(wasm32)
+    #else
+    #error("Unsupported platform")
+    #endif
+  }
+
+  fileprivate static func unlock(_ platformLock: PlatformLock) {
+    #if canImport(Darwin.os.lock)
+    os_unfair_lock_unlock(platformLock)
+    #elseif canImport(Glibc) || canImport(Musl) || canImport(Bionic)
+    let result = pthread_mutex_unlock(platformLock)
+    precondition(result == 0, "pthread_mutex_unlock failed")
+    #elseif canImport(WinSDK)
+    ReleaseSRWLockExclusive(platformLock)
+    #elseif arch(wasm32)
+    #else
+    #error("Unsupported platform")
+    #endif
+  }
+
+  static func allocate() -> Lock {
+    let platformLock = PlatformLock.allocate(capacity: 1)
+    initialize(platformLock)
+    return Lock(platformLock)
+  }
+
+  func deinitialize() {
+    Lock.deinitialize(platformLock)
+    platformLock.deallocate()
+  }
+
+  func lock() {
+    Lock.lock(platformLock)
+  }
+
+  func unlock() {
+    Lock.unlock(platformLock)
+  }
 
-  private let buffer: ManagedBuffer<State, UnsafeRawPointer>
+  /// Acquire the lock for the duration of the given block.
+  ///
+  /// This convenience method should be preferred to `lock` and `unlock` in
+  /// most situations, as it ensures that the lock will be released regardless
+  /// of how `body` exits.
+  ///
+  /// - Parameter body: The block to execute while holding the lock.
+  /// - Returns: The value returned by the block.
+  func withLock<T>(_ body: () throws -> T) rethrows -> T {
+    self.lock()
+    defer {
+      self.unlock()
+    }
+    return try body()
+  }
+
+  // specialise Void return (for performance)
+  func withLockVoid(_ body: () throws -> Void) rethrows {
+    try self.withLock(body)
+  }
+}
 
-  internal init(_ buffer: ManagedBuffer<State, UnsafeRawPointer>) {
-    self.buffer = buffer
+struct _ManagedCriticalState<State> {
+  private final class LockedBuffer: ManagedBuffer<State, Lock.Primitive> {
+    deinit {
+      withUnsafeMutablePointerToElements { Lock.deinitialize($0) }
+    }
   }
-  
-  internal init(_ initial: State) {
-    let roundedSize = (_lockSize() + MemoryLayout<UnsafeRawPointer>.size - 1) / MemoryLayout<UnsafeRawPointer>.size 
-    self.init(LockedBuffer.create(minimumCapacity: Swift.max(roundedSize, 1)) { buffer in
-      buffer.withUnsafeMutablePointerToElements { _lockInit(UnsafeRawPointer($0)) }
+
+  private let buffer: ManagedBuffer<State, Lock.Primitive>
+
+  init(_ initial: State) {
+    buffer = LockedBuffer.create(minimumCapacity: 1) { buffer in
+      buffer.withUnsafeMutablePointerToElements { Lock.initialize($0) }
       return initial
-    })
+    }
   }
 
-  internal func withCriticalRegion<R>(
-    _ critical: (inout State) throws -> R
-  ) rethrows -> R {
+  func withCriticalRegion<R>(_ critical: (inout State) throws -> R) rethrows -> R {
     try buffer.withUnsafeMutablePointers { header, lock in
-      _lockLock(UnsafeRawPointer(lock))
-      defer {
-        _lockUnlock(UnsafeRawPointer(lock))
-      }
+      Lock.lock(lock)
+      defer { Lock.unlock(lock) }
       return try critical(&header.pointee)
     }
   }
 }
 
-@available(SwiftStdlib 5.9, *)
-extension _ManagedCriticalState: @unchecked Sendable where State: Sendable { }
+extension _ManagedCriticalState: @unchecked Sendable where State: Sendable {}
+
 
 @available(SwiftStdlib 5.9, *)
 extension _ManagedCriticalState: Identifiable {
diff --git a/stdlib/public/Observation/Sources/Observation/ObservationRegistrar.swift b/stdlib/public/Observation/Sources/Observation/ObservationRegistrar.swift
index 3c356381bee63..eb7dfa3f89ea8 100644
--- a/stdlib/public/Observation/Sources/Observation/ObservationRegistrar.swift
+++ b/stdlib/public/Observation/Sources/Observation/ObservationRegistrar.swift
@@ -203,7 +203,7 @@ public struct ObservationRegistrar: Sendable {
   ///
   /// You don't need to create an instance of
   /// ``Observation/ObservationRegistrar`` when using the
-  /// ``Observation/Observable()`` macro to indicate observably
+  /// ``Observation/Observable()`` macro to indicate observability
   /// of a type.
   public init() {
   }
diff --git a/stdlib/public/Observation/Sources/Observation/Observations.swift b/stdlib/public/Observation/Sources/Observation/Observations.swift
new file mode 100644
index 0000000000000..f87cc24eaf72f
--- /dev/null
+++ b/stdlib/public/Observation/Sources/Observation/Observations.swift
@@ -0,0 +1,281 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+//
+//===----------------------------------------------------------------------===//
+
+import _Concurrency
+
+@usableFromInline
+@available(SwiftStdlib 5.1, *)
+@_silgen_name("swift_task_addCancellationHandler")
+func _taskAddCancellationHandler(handler: () -> Void) -> UnsafeRawPointer /*CancellationNotificationStatusRecord*/
+
+@usableFromInline
+@available(SwiftStdlib 5.1, *)
+@_silgen_name("swift_task_removeCancellationHandler")
+func _taskRemoveCancellationHandler(
+  record: UnsafeRawPointer /*CancellationNotificationStatusRecord*/
+)
+
+func withIsolatedTaskCancellationHandler<T: Sendable>(
+  operation: @isolated(any) () async throws -> T,
+  onCancel handler: @Sendable () -> Void,
+  isolation: isolated (any Actor)? = #isolation
+) async rethrows -> T {
+  // unconditionally add the cancellation record to the task.
+  // if the task was already cancelled, it will be executed right away.
+  let record = _taskAddCancellationHandler(handler: handler)
+  defer { _taskRemoveCancellationHandler(record: record) }
+
+  return try await operation()
+}
+
+/// An asychronous sequence generated from a closure that tracks the transactional changes of `@Observable` types.
+///
+/// `Observations` conforms to `AsyncSequence`, providing a intutive and safe mechanism to track changes to
+/// types that are marked as `@Observable` by using Swift Concurrency to indicate transactional boundaries
+/// starting from the willSet of the first mutation to the next suspension point of the safe access.
+@available(SwiftStdlib 6.2, *)
+public struct Observations<Element: Sendable, Failure: Error>: AsyncSequence, Sendable {
+  public enum Iteration: Sendable {
+    case next(Element)
+    case finish
+  }
+  
+  struct State {
+    enum Continuation {
+      case cancelled
+      case active(UnsafeContinuation<Void, Never>)
+      func resume() {
+        switch self {
+        case .cancelled: break
+        case .active(let continuation): continuation.resume()
+        }
+      }
+    }
+    var id = 0
+    var continuations: [Int: Continuation] = [:]
+    var dirty = false
+    
+    // create a generation id for the unique identification of the continuations
+    // this allows the shared awaiting of the willSets.
+    // Most likely, there wont be more than a handful of active iterations
+    // so this only needs to be unique for those active iterations
+    // that are in the process of calling next.
+    static func generation(_ state: _ManagedCriticalState<State>) -> Int {
+      state.withCriticalRegion { state in
+        defer { state.id &+= 1 }
+        return state.id
+      }
+    }
+    
+    // the cancellation of awaiting on willSet only ferries in resuming early
+    // it is the responsability of the caller to check if the task is actually
+    // cancelled after awaiting the willSet to act accordingly.
+    static func cancel(_ state: _ManagedCriticalState<State>, id: Int) {
+      state.withCriticalRegion { state in
+        guard let continuation = state.continuations.removeValue(forKey: id) else {
+          // if there was no continuation yet active (e.g. it was cancelled at
+          // the start of the invocation, then put a tombstone in to gate that
+          // resuming later
+          state.continuations[id] = .cancelled
+          return nil as Continuation?
+        }
+        return continuation
+      }?.resume()
+    }
+    
+    // fire off ALL awaiting willChange continuations such that they are no
+    // longer pending.
+    static func emitWillChange(_ state: _ManagedCriticalState<State>) {
+      let continuations = state.withCriticalRegion { state in
+        // if there are no continuations present then we have to set the state as dirty
+        // else if this is uncondiitonally set the state might produce duplicate events
+        // one for the dirty and one for the continuation.
+        if state.continuations.count == 0 {
+          state.dirty = true
+        }
+        defer {
+          state.continuations.removeAll()
+        }
+        return state.continuations.values
+      }
+      for continuation in continuations {
+        continuation.resume()
+      }
+    }
+    
+    // install a willChange continuation into the set of continuations
+    // this must take a locally unique id (to the active calls of next)
+    static func willChange(isolation iterationIsolation: isolated (any Actor)? = #isolation, state: _ManagedCriticalState<State>, id: Int) async {
+      return await withUnsafeContinuation(isolation: iterationIsolation) { continuation in
+        state.withCriticalRegion { state in
+          defer { state.dirty = false }
+          switch state.continuations[id] {
+          case .cancelled:
+            return continuation as UnsafeContinuation<Void, Never>?
+          case .active:
+            // the Iterator itself cannot be shared across isolations so any call to next that may share an id is a misbehavior
+            // or an internal book-keeping failure
+            fatalError("Iterator incorrectly shared across task isolations")
+          case .none:
+            if state.dirty {
+              return continuation
+            } else {
+              state.continuations[id] = .active(continuation)
+              return nil
+            }
+          }
+        }?.resume()
+      }
+    }
+  }
+  
+  // @isolated(any) closures cannot be composed and retain or forward their isolation
+  // this basically would be replaced with `{ .next(elementProducer()) }` if that
+  // were to become possible.
+  enum Emit {
+    case iteration(@isolated(any) @Sendable () throws(Failure) -> Iteration)
+    case element(@isolated(any) @Sendable () throws(Failure) -> Element)
+    
+    var isolation: (any Actor)? {
+      switch self {
+      case .iteration(let closure): closure.isolation
+      case .element(let closure): closure.isolation
+      }
+    }
+  }
+  
+  let state: _ManagedCriticalState<State>
+  let emit: Emit
+  
+  // internal funnel method for initialziation
+  internal init(emit: Emit) {
+    self.emit = emit
+    self.state = _ManagedCriticalState(State())
+  }
+  
+  /// Constructs an asynchronous sequence for a given closure by tracking changes of `@Observable` types.
+  ///
+  /// The emit closure is responsible for extracting a value out of a single or many `@Observable` types.
+  ///
+  /// - Parameters:
+  ///     - isolation:  The concurrency isolation domain of the caller.
+  ///     - emit: A closure to generate an element for the sequence.
+  public init(
+    @_inheritActorContext _ emit: @escaping @isolated(any) @Sendable () throws(Failure) -> Element
+  ) {
+    self.init(emit: .element(emit))
+  }
+  
+  /// Constructs an asynchronous sequence for a given closure by tracking changes of `@Observable` types.
+  ///
+  /// The emit closure is responsible for extracting a value out of a single or many `@Observable` types. This method
+  /// continues to be invoked until the .finished option is returned or an error is thrown.
+  ///
+  /// - Parameters:
+  ///     - isolation:  The concurrency isolation domain of the caller.
+  ///     - emit: A closure to generate an element for the sequence.
+  public static func untilFinished(
+    @_inheritActorContext _ emit: @escaping @isolated(any) @Sendable () throws(Failure) -> Iteration
+  ) -> Observations<Element, Failure> {
+    .init(emit: .iteration(emit))
+  }
+  
+  public struct Iterator: AsyncIteratorProtocol {
+    // the state ivar serves two purposes:
+    // 1) to store a critical region of state of the mutations
+    // 2) to idenitify the termination of _this_ sequence
+    var state: _ManagedCriticalState<State>?
+    let emit: Emit
+    var started = false
+    
+    // this is the primary implementation of the tracking
+    // it is bound to be called on the specified isolation of the construction
+    fileprivate static func trackEmission(isolation trackingIsolation: isolated (any Actor)?, state: _ManagedCriticalState<State>, emit: Emit) throws(Failure) -> Iteration {
+      // this ferries in an intermediate form with Result to skip over `withObservationTracking` not handling errors being thrown
+      // particularly this case is that the error is also an iteration state transition data point (it terminates the sequence)
+      // so we need to hold that to get a chance to catch and clean-up
+      let result = withObservationTracking {
+        switch emit {
+        case .element(let element):
+          Result(catching: element).map { Iteration.next($0) }
+        case .iteration(let iteration):
+          Result(catching: iteration)
+        }
+      } onChange: { [state] in
+        // resume all cases where the awaiting continuations are awaiting a willSet
+        State.emitWillChange(state)
+      }
+      return try result.get()
+    }
+    
+    fileprivate mutating func terminate(throwing failure: Failure? = nil, id: Int) throws(Failure) -> Element? {
+      // this is purely defensive to any leaking out of iteration generation ids
+      state?.withCriticalRegion { state in
+        state.continuations.removeValue(forKey: id)
+      }?.resume()
+      // flag the sequence as terminal by nil'ing out the state
+      state = nil
+      if let failure {
+        throw failure
+      } else {
+        return nil
+      }
+    }
+    
+    fileprivate mutating func trackEmission(isolation iterationIsolation: isolated (any Actor)?, state: _ManagedCriticalState<State>, id: Int) async throws(Failure) -> Element? {
+      guard !Task.isCancelled else {
+        // the task was cancelled while awaiting a willChange so ensure a proper termination
+        return try terminate(id: id)
+      }
+      // start by directly tracking the emission via a withObservation tracking on the isolation specified from the init
+      switch try await Iterator.trackEmission(isolation: emit.isolation, state: state, emit: emit) {
+      case .finish: return try terminate(id: id)
+      case .next(let element): return element
+      }
+    }
+    
+    public mutating func next(isolation iterationIsolation: isolated (any Actor)? = #isolation) async throws(Failure) -> Element? {
+      // early exit if the sequence is terminal already
+      guard let state else { return nil }
+      // set up an id for this generation
+      let id = State.generation(state)
+      do {
+        // there are two versions;
+        // either the tracking has never yet started at all and we need to prime the pump for this specific iterator
+        // or the tracking has already started and we are going to await a change
+        if !started {
+          started = true
+          return try await trackEmission(isolation: iterationIsolation, state: state, id: id)
+        } else {
+          // wait for the willChange (and NOT the value itself)
+          // since this is going to be on the isolation of the object (e.g. the isolation specified in the initialization)
+          // this will mean our next await for the emission will ensure the suspension return of the willChange context
+          // back to the trailing edges of the mutations. In short, this enables the transactionality bounded by the
+          // isolation of the mutation.
+          await withIsolatedTaskCancellationHandler(operation: {
+            await State.willChange(isolation: iterationIsolation, state: state, id: id)
+          }, onCancel: {
+            // ensure to clean out our continuation uon cancellation
+            State.cancel(state, id: id)
+          }, isolation: iterationIsolation)
+          return try await trackEmission(isolation: iterationIsolation, state: state, id: id)
+        }
+      } catch {
+        // the user threw a failure in the closure so propigate that outwards and terminate the sequence
+        return try terminate(throwing: error, id: id)
+      }
+    }
+  }
+  
+  public func makeAsyncIterator() -> Iterator {
+    Iterator(state: state, emit: emit)
+  }
+}
diff --git a/stdlib/public/Platform/CMakeLists.txt b/stdlib/public/Platform/CMakeLists.txt
index 9ae7a977ac400..083b5578eb42c 100644
--- a/stdlib/public/Platform/CMakeLists.txt
+++ b/stdlib/public/Platform/CMakeLists.txt
@@ -4,130 +4,11 @@ set(swift_platform_sources
 set(swift_platform_gyb_sources
     tgmath.swift.gyb)
 
-set(darwin_depends)
-if(NOT BUILD_STANDALONE)
-  # This is overly conservative, but we have so few API notes files that
-  # haven't migrated to the Swift repo that it's probably fine in practice.
-  list(APPEND darwin_depends copy_apinotes)
-endif()
-
 set(swift_platform_compile_flags)
 if(SWIFT_ENABLE_REFLECTION)
   list(APPEND swift_platform_compile_flags "-DSWIFT_ENABLE_REFLECTION")
 endif()
 
-set(swiftDarwin_target_sdks ALL_APPLE_PLATFORMS)
-if(SWIFT_FREESTANDING_FLAVOR STREQUAL "apple" AND NOT SWIFT_FREESTANDING_IS_DARWIN)
-  set(swiftDarwin_target_sdks ALL_APPLE_PLATFORMS FREESTANDING)
-endif()
-
-set(swiftDarwin_common_options
-      IS_SDK_OVERLAY
-      ${swift_platform_sources}
-      POSIXError.swift
-      MachError.swift
-
-      "${SWIFT_SOURCE_DIR}/stdlib/linker-support/magic-symbols-for-install-name.c"
-
-      GYB_SOURCES
-        ${swift_platform_gyb_sources}
-        Darwin.swift.gyb
-
-      SWIFT_COMPILE_FLAGS
-        ${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS}
-        ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
-        -Xfrontend -disable-objc-attr-requires-foundation-module
-        ${swift_platform_compile_flags}
-      LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
-      DEPENDS ${darwin_depends})
-
-
-if(BOOTSTRAPPING_MODE STREQUAL "BOOTSTRAPPING" AND
-   SWIFT_HOST_VARIANT_SDK IN_LIST SWIFT_DARWIN_PLATFORMS)
-
-  set(swiftDarwin_common_bootstrapping_options
-      ${swiftDarwin_common_options}
-      SHARED
-      IS_STDLIB
-      SDK ${SWIFT_HOST_VARIANT_SDK}
-      ARCHITECTURE ${SWIFT_HOST_VARIANT_ARCH}
-      INSTALL_IN_COMPONENT "never_install")
-
-  set(b0_deps swiftCore-bootstrapping0)
-  set(b1_deps swiftCore-bootstrapping1)
-  if(CMAKE_BUILD_TYPE STREQUAL "Debug")
-    set(b0_deps ${b0_deps} swiftSwiftOnoneSupport-bootstrapping0)
-    set(b1_deps ${b1_deps} swiftSwiftOnoneSupport-bootstrapping1)
-  endif()
-
-  add_swift_target_library_single(swiftDarwin-bootstrapping0 swiftDarwin
-      ${swiftDarwin_common_bootstrapping_options}
-      FILE_DEPENDS ${b0_deps}
-      BOOTSTRAPPING 0)
-
-  add_swift_target_library_single(swiftDarwin-bootstrapping1 swiftDarwin
-      ${swiftDarwin_common_bootstrapping_options}
-      FILE_DEPENDS ${b1_deps}
-      BOOTSTRAPPING 1)
-endif()
-
-add_swift_target_library(swiftDarwin ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES}
-    ${swiftDarwin_common_options}
-    TARGET_SDKS "${swiftDarwin_target_sdks}"
-    INSTALL_IN_COMPONENT sdk-overlay
-    MACCATALYST_BUILD_FLAVOR "zippered"
-    INSTALL_BINARY_SWIFTMODULE FALSE)
-
-if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
-  set(SWIFT_ENABLE_REFLECTION OFF)
-
-  add_custom_target(embedded-darwin)
-  add_dependencies(embedded-libraries embedded-darwin)
-  foreach(entry ${EMBEDDED_STDLIB_TARGET_TRIPLES})
-    string(REGEX REPLACE "[ \t]+" ";" list "${entry}")
-    list(GET list 0 arch)
-    list(GET list 1 mod)
-    list(GET list 2 triple)
-
-    if(NOT "${mod}" MATCHES "-macos$")
-      continue()
-    endif()
-
-    set(SWIFT_SDK_embedded_ARCH_${arch}_MODULE "${mod}")
-    set(SWIFT_SDK_embedded_LIB_SUBDIR "embedded")
-    set(SWIFT_SDK_embedded_ARCH_${arch}_TRIPLE "${triple}")
-    set(SWIFT_SDK_embedded_PATH ${SWIFT_SDK_OSX_PATH})
-    set(SWIFT_SDK_embedded_ARCH_${arch}_PATH ${SWIFT_SDK_OSX_PATH})
-    set(SWIFT_SDK_embedded_USE_ISYSROOT TRUE)
-    add_swift_target_library_single(
-      embedded-darwin-${mod}
-      swiftDarwin
-      ONLY_SWIFTMODULE
-      IS_SDK_OVERLAY IS_FRAGILE
-
-      Platform.swift
-      TiocConstants.swift
-      POSIXError.swift
-      MachError.swift
-
-      GYB_SOURCES
-        tgmath.swift.gyb
-        Darwin.swift.gyb
-      
-      SWIFT_COMPILE_FLAGS
-        -Xcc -ffreestanding -enable-experimental-feature Embedded
-      C_COMPILE_FLAGS
-        -ffreestanding
-      MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
-      SDK "embedded"
-      ARCHITECTURE "${arch}"
-      DEPENDS embedded-stdlib-${mod}
-      INSTALL_IN_COMPONENT stdlib
-      )
-    add_dependencies(embedded-darwin embedded-darwin-${mod})
-  endforeach()
-endif()
-
 set(swiftGlibc_target_sdks CYGWIN FREEBSD OPENBSD LINUX HAIKU)
 if(SWIFT_FREESTANDING_FLAVOR STREQUAL "linux")
   set(swiftGlibc_target_sdks CYGWIN FREEBSD OPENBSD LINUX HAIKU FREESTANDING)
@@ -504,6 +385,7 @@ if("WASI" IN_LIST SWIFT_SDKS)
     set(arch_subdir "${SWIFT_SDK_WASI_LIB_SUBDIR}/${arch}")
     set(module_dir "${SWIFTLIB_DIR}/${arch_subdir}")
     set(module_dir_static "${SWIFTSTATICLIB_DIR}/${arch_subdir}")
+    set(module_dir_embedded "${SWIFTLIB_DIR}/embedded/${arch}")
 
     add_custom_command_target(
       copy_wasilibc_modulemap_resource
@@ -529,6 +411,24 @@ if("WASI" IN_LIST SWIFT_SDKS)
                                  COMPONENT sdk-overlay)
     endif()
 
+    if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
+      add_custom_command_target(
+        copy_wasilibc_modulemap_embedded_resource
+        COMMAND
+          "${CMAKE_COMMAND}" "-E" "make_directory" ${module_dir} ${module_dir_embedded}
+        COMMAND
+          "${CMAKE_COMMAND}" "-E" "copy_if_different"
+            "${CMAKE_CURRENT_SOURCE_DIR}/${wasilibc_modulemap_source}" ${module_dir_embedded}
+        OUTPUT "${module_dir_embedded}/${wasilibc_modulemap_source}"
+        COMMENT "Copying WASILibc modulemap to resource directories")
+      add_dependencies(sdk-overlay ${copy_wasilibc_modulemap_embedded_resource})
+      list(APPEND wasilibc_modulemap_target_list ${copy_wasilibc_modulemap_embedded_resource})
+
+      swift_install_in_component(FILES "${wasilibc_modulemap_source}"
+                                 DESTINATION "lib/swift/embedded/${arch}"
+                                 COMPONENT sdk-overlay)
+    endif()
+
     set(wasilibc_apinotes_source "SwiftWASILibc.apinotes")
     add_custom_command_target(
       copy_wasilibc_apinotes_resource
@@ -567,7 +467,46 @@ if(WINDOWS IN_LIST SWIFT_SDKS)
       ucrt.modulemap
       vcruntime.apinotes
       vcruntime.modulemap
-      winsdk.modulemap
+      winsdk_um.modulemap
+      winsdk_shared.modulemap
     DESTINATION "share"
     COMPONENT sdk-overlay)
 endif()
+
+if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
+  add_custom_target(embedded-stdlib-platform)
+  add_dependencies(embedded-libraries embedded-stdlib-platform)
+
+  if(SWIFT_WASI_SYSROOT_PATH)
+    set(arch "wasm32")
+    set(triple "wasm32-unknown-wasip1")
+
+    set(SWIFT_SDK_embedded_ARCH_${arch}_MODULE "${triple}")
+    set(SWIFT_SDK_embedded_LIB_SUBDIR "embedded")
+    set(SWIFT_SDK_embedded_ARCH_${arch}_TRIPLE "${triple}")
+    add_swift_target_library_single(
+      embedded-stdlib-platform-${triple}
+      swiftWASILibc
+      ONLY_SWIFTMODULE
+      IS_STDLIB IS_FRAGILE
+        ${swift_platform_sources}
+        POSIXError.swift
+
+      GYB_SOURCES
+        ${swift_platform_gyb_sources}
+        WASILibc.swift.gyb
+
+      SWIFT_COMPILE_FLAGS
+        -enable-experimental-feature Embedded
+        -Xfrontend -emit-empty-object-file
+
+      MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
+      SDK "embedded"
+      ARCHITECTURE "${arch}"
+      ARCHITECTURE_SUBDIR_NAME "${triple}"
+      DEPENDS embedded-stdlib-${triple} wasilibc_modulemap
+      INSTALL_IN_COMPONENT sdk-overlay
+    )
+    add_dependencies(embedded-stdlib-platform embedded-stdlib-platform-${triple})
+  endif()
+endif()
diff --git a/stdlib/public/Platform/Darwin.swift.gyb b/stdlib/public/Platform/Darwin.swift.gyb
deleted file mode 100644
index f0153220ff968..0000000000000
--- a/stdlib/public/Platform/Darwin.swift.gyb
+++ /dev/null
@@ -1,81 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-@_exported import Darwin // Clang module
-
-public let MAP_FAILED: UnsafeMutableRawPointer! = UnsafeMutableRawPointer(bitPattern: -1)
-
-//  Constants defined by <math.h>
-@available(swift, deprecated: 3.0, message: "Please use 'Double.pi' or '.pi' to get the value of correct type and avoid casting.")
-public let M_PI = Double.pi
-
-@available(swift, deprecated: 3.0, message: "Please use 'Double.pi / 2' or '.pi / 2' to get the value of correct type and avoid casting.")
-public let M_PI_2 = Double.pi / 2
-
-@available(swift, deprecated: 3.0, message: "Please use 'Double.pi / 4' or '.pi / 4' to get the value of correct type and avoid casting.")
-public let M_PI_4 = Double.pi / 4
-
-@available(swift, deprecated: 3.0, message: "Please use '2.squareRoot()'.")
-public let M_SQRT2 = 2.squareRoot()
-
-@available(swift, deprecated: 3.0, message: "Please use '0.5.squareRoot()'.")
-public let M_SQRT1_2 = 0.5.squareRoot()
-
-//  Constants defined by <float.h>
-@available(swift, deprecated: 3.0, message: "Please use 'T.radix' to get the radix of a FloatingPoint type 'T'.")
-public let FLT_RADIX = Double.radix
-
-%for type, prefix in [('Float', 'FLT'), ('Double', 'DBL'), ('Float80', 'LDBL')]:
-% if type == "Float80":
-#if arch(i386) || arch(x86_64)
-% end
-//  Where does the 1 come from? C counts the usually-implicit leading
-//  significand bit, but Swift does not. Neither is really right or wrong.
-@available(swift, deprecated: 3.0, message: "Please use '${type}.significandBitCount + 1'.")
-public let ${prefix}_MANT_DIG = ${type}.significandBitCount + 1
-
-//  Where does the 1 come from? C models floating-point numbers as having a
-//  significand in [0.5, 1), but Swift (following IEEE 754) considers the
-//  significand to be in [1, 2). This rationale applies to ${prefix}_MIN_EXP
-//  as well.
-@available(swift, deprecated: 3.0, message: "Please use '${type}.greatestFiniteMagnitude.exponent + 1'.")
-public let ${prefix}_MAX_EXP = ${type}.greatestFiniteMagnitude.exponent + 1
-
-@available(swift, deprecated: 3.0, message: "Please use '${type}.leastNormalMagnitude.exponent + 1'.")
-public let ${prefix}_MIN_EXP = ${type}.leastNormalMagnitude.exponent + 1
-
-@available(swift, deprecated: 3.0, message: "Please use '${type}.greatestFiniteMagnitude' or '.greatestFiniteMagnitude'.")
-public let ${prefix}_MAX = ${type}.greatestFiniteMagnitude
-
-@available(swift, deprecated: 3.0, message: "Please use '${type}.ulpOfOne' or '.ulpOfOne'.")
-public let ${prefix}_EPSILON = ${type}.ulpOfOne
-
-@available(swift, deprecated: 3.0, message: "Please use '${type}.leastNormalMagnitude' or '.leastNormalMagnitude'.")
-public let ${prefix}_MIN = ${type}.leastNormalMagnitude
-
-@available(swift, deprecated: 3.0, message: "Please use '${type}.leastNonzeroMagnitude' or '.leastNonzeroMagnitude'.")
-public let ${prefix}_TRUE_MIN = ${type}.leastNonzeroMagnitude
-
-% if type == "Float80":
-#endif
-% end
-%end
-
-// Macros defined in bsd/sys/proc.h that do not import into Swift.
-extension extern_proc {
-    // #define p_starttime p_un.__p_starttime
-    @_transparent
-    public var p_starttime: timeval {
-        get { return self.p_un.__p_starttime }
-        set { self.p_un.__p_starttime = newValue }
-    }
-}
diff --git a/stdlib/public/Platform/MachError.swift b/stdlib/public/Platform/MachError.swift
deleted file mode 100644
index 1dfecd66a5f1c..0000000000000
--- a/stdlib/public/Platform/MachError.swift
+++ /dev/null
@@ -1,205 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-#if (os(macOS) || os(iOS) || os(tvOS) || os(watchOS) || os(visionOS)) && _runtime(_ObjC)
-/// Enumeration describing Mach error codes.
-@objc
-public enum MachErrorCode : Int32 {
-  case success                  = 0
-
-  /// Specified address is not currently valid.
-  case invalidAddress           = 1
-
-  /// Specified memory is valid, but does not permit the required
-  /// forms of access.
-  case protectionFailure        = 2
-
-  /// The address range specified is already in use, or no address
-  /// range of the size specified could be found.  
-  case noSpace                  = 3
-
-  /// The function requested was not applicable to this type of
-  /// argument, or an argument is invalid.
-  case invalidArgument          = 4
-
-  /// The function could not be performed.  A catch-all.
-  case failure                  = 5
-
-  /// A system resource could not be allocated to fulfill this
-  /// request.  This failure may not be permanent.
-  case resourceShortage         = 6
-
-  /// The task in question does not hold receive rights for the port
-  /// argument.
-  case notReceiver              = 7
-
-  /// Bogus access restriction.
-  case noAccess                 = 8
-
-  /// During a page fault, the target address refers to a memory
-  /// object that has been destroyed.  This failure is permanent.
-  case memoryFailure            = 9
-
-  /// During a page fault, the memory object indicated that the data
-  /// could not be returned.  This failure may be temporary; future
-  /// attempts to access this same data may succeed, as defined by the
-  /// memory object.
-  case memoryError              = 10
-
-  /// The receive right is already a member of the portset.
-  case alreadyInSet             = 11
-
-  /// The receive right is not a member of a port set.
-  case notInSet                 = 12
-
-  /// The name already denotes a right in the task.
-  case nameExists               = 13
-
-  /// The operation was aborted.  Ipc code will catch this and reflect
-  /// it as a message error.
-  case aborted                  = 14
-
-  /// The name doesn't denote a right in the task.
-  case invalidName              = 15
-
-  /// Target task isn't an active task.
-  case invalidTask              = 16
-
-  /// The name denotes a right, but not an appropriate right.
-  case invalidRight             = 17
-
-  /// A blatant range error.
-  case invalidValue             = 18
-
-  /// Operation would overflow limit on user-references.
-  case userReferencesOverflow   = 19
-
-  /// The supplied (port) capability is improper.
-  case invalidCapability        = 20
-
-  /// The task already has send or receive rights for the port under
-  /// another name.
-  case rightExists              = 21
-
-  /// Target host isn't actually a host.
-  case invalidHost              = 22
-
-  /// An attempt was made to supply "precious" data for memory that is
-  /// already present in a memory object.
-  case memoryPresent            = 23
-
-  /// A page was requested of a memory manager via
-  /// memory_object_data_request for an object using a
-  /// MEMORY_OBJECT_COPY_CALL strategy, with the VM_PROT_WANTS_COPY
-  /// flag being used to specify that the page desired is for a copy
-  /// of the object, and the memory manager has detected the page was
-  /// pushed into a copy of the object while the kernel was walking
-  /// the shadow chain from the copy to the object. This error code is
-  /// delivered via memory_object_data_error and is handled by the
-  /// kernel (it forces the kernel to restart the fault). It will not
-  /// be seen by users.
-  case memoryDataMoved          = 24
-
-  /// A strategic copy was attempted of an object upon which a quicker
-  /// copy is now possible.  The caller should retry the copy using
-  /// vm_object_copy_quickly. This error code is seen only by the
-  /// kernel.
-  case memoryRestartCopy        = 25
-
-  /// An argument applied to assert processor set privilege was not a
-  /// processor set control port.
-  case invalidProcessorSet      = 26
-
-  /// The specified scheduling attributes exceed the thread's limits.
-  case policyLimit              = 27
-
-  /// The specified scheduling policy is not currently enabled for the
-  /// processor set.
-  case invalidPolicy            = 28
-
-  /// The external memory manager failed to initialize the memory object.
-  case invalidObject            = 29
-
-  /// A thread is attempting to wait for an event for which there is
-  /// already a waiting thread.
-  case alreadyWaiting           = 30
-
-  /// An attempt was made to destroy the default processor set.
-  case defaultSet               = 31
-
-  /// An attempt was made to fetch an exception port that is
-  /// protected, or to abort a thread while processing a protected
-  /// exception.
-  case exceptionProtected       = 32
-
-  /// A ledger was required but not supplied.
-  case invalidLedger            = 33
-
-  /// The port was not a memory cache control port.
-  case invalidMemoryControl     = 34
-
-  /// An argument supplied to assert security privilege was not a host
-  /// security port.
-  case invalidSecurity          = 35
-
-  /// thread_depress_abort was called on a thread which was not
-  /// currently depressed.
-  case notDepressed             = 36
-
-  /// Object has been terminated and is no longer available.
-  case terminated               = 37
-
-  /// Lock set has been destroyed and is no longer available.
-  case lockSetDestroyed         = 38
-
-  /// The thread holding the lock terminated before releasing the lock.
-  case lockUnstable             = 39
-
-  /// The lock is already owned by another thread.
-  case lockOwned                = 40
-
-  /// The lock is already owned by the calling thread.
-  case lockOwnedSelf            = 41
-
-  /// Semaphore has been destroyed and is no longer available.
-  case semaphoreDestroyed       = 42
-
-  /// Return from RPC indicating the target server was terminated
-  /// before it successfully replied.
-  case rpcServerTerminated      = 43
-
-  /// Terminate an orphaned activation.
-  case rpcTerminateOrphan       = 44
-
-  /// Allow an orphaned activation to continue executing.
-  case rpcContinueOrphan        = 45
-
-  /// Empty thread activation (No thread linked to it).
-  case notSupported             = 46
-
-  /// Remote node down or inaccessible.
-  case nodeDown                 = 47
-
-  /// A signalled thread was not actually waiting.
-  case notWaiting               = 48
-
-  /// Some thread-oriented operation (semaphore_wait) timed out.
-  case operationTimedOut        = 49
-
-  /// During a page fault, indicates that the page was rejected as a
-  /// result of a signature check.
-  case codesignError            = 50
-
-  /// The requested property cannot be changed at this time.
-  case policyStatic             = 51
-}
-#endif // (os(macOS) || os(iOS) || os(tvOS) || os(watchOS) || os(visionOS)) && _runtime(_ObjC)
diff --git a/stdlib/public/Platform/POSIXError.swift b/stdlib/public/Platform/POSIXError.swift
index a655bd655e4a5..b379fac5a20cc 100644
--- a/stdlib/public/Platform/POSIXError.swift
+++ b/stdlib/public/Platform/POSIXError.swift
@@ -10,260 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if (os(macOS) || os(iOS) || os(tvOS) || os(watchOS) || os(visionOS)) && _runtime(_ObjC)
-
-/// Enumeration describing POSIX error codes.
-@objc
-public enum POSIXErrorCode: Int32, Sendable {
-  /// Operation not permitted.
-  case EPERM           = 1
-  /// No such file or directory.
-  case ENOENT          = 2
-  /// No such process.
-  case ESRCH           = 3
-  /// Interrupted system call.
-  case EINTR           = 4
-  /// Input/output error.
-  case EIO             = 5
-  /// Device not configured.
-  case ENXIO           = 6
-  /// Argument list too long.
-  case E2BIG           = 7
-  /// Exec format error.
-  case ENOEXEC         = 8
-  /// Bad file descriptor.
-  case EBADF           = 9
-  /// No child processes.
-  case ECHILD          = 10
-  /// Resource deadlock avoided.
-  case EDEADLK         = 11
-  /// 11 was EAGAIN.
-  /// Cannot allocate memory.
-  case ENOMEM          = 12
-  /// Permission denied.
-  case EACCES          = 13
-  /// Bad address.
-  case EFAULT          = 14
-  /// Block device required.
-  case ENOTBLK         = 15
-  /// Device / Resource busy.
-  case EBUSY           = 16
-  /// File exists.
-  case EEXIST          = 17
-  /// Cross-device link.
-  case EXDEV           = 18
-  /// Operation not supported by device.
-  case ENODEV          = 19
-  /// Not a directory.
-  case ENOTDIR         = 20
-  /// Is a directory.
-  case EISDIR          = 21
-  /// Invalid argument.
-  case EINVAL          = 22
-  /// Too many open files in system.
-  case ENFILE          = 23
-  /// Too many open files.
-  case EMFILE          = 24
-  /// Inappropriate ioctl for device.
-  case ENOTTY          = 25
-  /// Text file busy.
-  case ETXTBSY         = 26
-  /// File too large.
-  case EFBIG           = 27
-  /// No space left on device.
-  case ENOSPC          = 28
-  /// Illegal seek.
-  case ESPIPE          = 29
-  /// Read-only file system.
-  case EROFS           = 30
-  /// Too many links.
-  case EMLINK          = 31
-  /// Broken pipe.
-  case EPIPE           = 32
-    
-  /// math software.
-  /// Numerical argument out of domain.
-  case EDOM            = 33
-  /// Result too large.
-  case ERANGE          = 34
-    
-  /// non-blocking and interrupt i/o.
-  /// Resource temporarily unavailable.
-  case EAGAIN          = 35
-  /// Operation would block.
-  public static var EWOULDBLOCK: POSIXErrorCode { return EAGAIN }
-  /// Operation now in progress.
-  case EINPROGRESS     = 36
-  /// Operation already in progress.
-  case EALREADY        = 37
-    
-  /// ipc/network software -- argument errors.
-  /// Socket operation on non-socket.
-  case ENOTSOCK        = 38
-  /// Destination address required.
-  case EDESTADDRREQ    = 39
-  /// Message too long.
-  case EMSGSIZE        = 40
-  /// Protocol wrong type for socket.
-  case EPROTOTYPE      = 41
-  /// Protocol not available.
-  case ENOPROTOOPT     = 42
-  /// Protocol not supported.
-  case EPROTONOSUPPORT = 43
-  /// Socket type not supported.
-  case ESOCKTNOSUPPORT = 44
-  /// Operation not supported.
-  case ENOTSUP         = 45
-  /// Protocol family not supported.
-  case EPFNOSUPPORT    = 46
-  /// Address family not supported by protocol family.
-  case EAFNOSUPPORT    = 47
-  /// Address already in use.
-  case EADDRINUSE      = 48
-  /// Can't assign requested address.
-  case EADDRNOTAVAIL   = 49
-    
-  /// ipc/network software -- operational errors
-  /// Network is down.
-  case ENETDOWN        = 50
-  /// Network is unreachable.
-  case ENETUNREACH     = 51
-  /// Network dropped connection on reset.
-  case ENETRESET       = 52
-  /// Software caused connection abort.
-  case ECONNABORTED    = 53
-  /// Connection reset by peer.
-  case ECONNRESET      = 54
-  /// No buffer space available.
-  case ENOBUFS         = 55
-  /// Socket is already connected.
-  case EISCONN         = 56
-  /// Socket is not connected.
-  case ENOTCONN        = 57
-  /// Can't send after socket shutdown.
-  case ESHUTDOWN       = 58
-  /// Too many references: can't splice.
-  case ETOOMANYREFS    = 59
-  /// Operation timed out.
-  case ETIMEDOUT       = 60
-  /// Connection refused.
-  case ECONNREFUSED    = 61
-    
-  /// Too many levels of symbolic links.
-  case ELOOP           = 62
-  /// File name too long.
-  case ENAMETOOLONG    = 63
-    
-  /// Host is down.
-  case EHOSTDOWN       = 64
-  /// No route to host.
-  case EHOSTUNREACH    = 65
-  /// Directory not empty.
-  case ENOTEMPTY       = 66
-    
-  /// quotas & mush.
-  /// Too many processes.
-  case EPROCLIM        = 67
-  /// Too many users.
-  case EUSERS          = 68
-  /// Disc quota exceeded.
-  case EDQUOT          = 69
-    
-  /// Network File System.
-  /// Stale NFS file handle.
-  case ESTALE          = 70
-  /// Too many levels of remote in path.
-  case EREMOTE         = 71
-  /// RPC struct is bad.
-  case EBADRPC         = 72
-  /// RPC version wrong.
-  case ERPCMISMATCH    = 73
-  /// RPC prog. not avail.
-  case EPROGUNAVAIL    = 74
-  /// Program version wrong.
-  case EPROGMISMATCH   = 75
-  /// Bad procedure for program.
-  case EPROCUNAVAIL    = 76
-    
-  /// No locks available.
-  case ENOLCK          = 77
-  /// Function not implemented.
-  case ENOSYS          = 78
-    
-  /// Inappropriate file type or format.
-  case EFTYPE          = 79
-  /// Authentication error.
-  case EAUTH           = 80
-  /// Need authenticator.
-  case ENEEDAUTH       = 81
-    
-  /// Intelligent device errors.
-  /// Device power is off.
-  case EPWROFF         = 82
-  /// Device error, e.g. paper out.
-  case EDEVERR         = 83
-    
-  /// Value too large to be stored in data type.
-  case EOVERFLOW       = 84
-
-  // MARK: Program loading errors.
-
-  /// Bad executable.
-  case EBADEXEC        = 85
-  /// Bad CPU type in executable.
-  case EBADARCH        = 86
-  /// Shared library version mismatch.
-  case ESHLIBVERS      = 87
-  /// Malformed Macho file.
-  case EBADMACHO       = 88
-    
-  /// Operation canceled.
-  case ECANCELED       = 89
-    
-  /// Identifier removed.
-  case EIDRM           = 90
-  /// No message of desired type.
-  case ENOMSG          = 91
-  /// Illegal byte sequence.
-  case EILSEQ          = 92
-  /// Attribute not found.
-  case ENOATTR         = 93
-    
-  /// Bad message.
-  case EBADMSG         = 94
-  /// Reserved.
-  case EMULTIHOP       = 95
-  /// No message available on STREAM.
-  case ENODATA         = 96
-  /// Reserved.
-  case ENOLINK         = 97
-  /// No STREAM resources.
-  case ENOSR           = 98
-  /// Not a STREAM.
-  case ENOSTR          = 99
-  /// Protocol error.
-  case EPROTO          = 100
-  /// STREAM ioctl timeout.
-  case ETIME           = 101
-    
-  /// No such policy registered.
-  case ENOPOLICY       = 103
-    
-  /// State not recoverable.
-  case ENOTRECOVERABLE = 104
-  /// Previous owner died.
-  case EOWNERDEAD      = 105
-  
-  /// Interface output queue is full.
-  case EQFULL          = 106
-  /// Must be equal largest errno.
-  public static var ELAST: POSIXErrorCode { return EQFULL }
-    
-  // FIXME: EOPNOTSUPP has different values depending on __DARWIN_UNIX03 and
-  // KERNEL.
-}
-
-#elseif os(Linux) || os(Android)
+#if os(Linux) || os(Android)
 
 /// Enumeration describing POSIX error codes.
 public enum POSIXErrorCode: Int32, Sendable {
diff --git a/stdlib/public/Platform/Platform.swift b/stdlib/public/Platform/Platform.swift
index 0c2d63a0cffdb..8c35ca3c1db39 100644
--- a/stdlib/public/Platform/Platform.swift
+++ b/stdlib/public/Platform/Platform.swift
@@ -13,77 +13,6 @@
 import SwiftShims
 import SwiftOverlayShims
 
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS)
-//===----------------------------------------------------------------------===//
-// MacTypes.h
-//===----------------------------------------------------------------------===//
-
-public var noErr: OSStatus { return 0 }
-
-/// The `Boolean` type declared in MacTypes.h and used throughout Core
-/// Foundation.
-///
-/// The C type is a typedef for `unsigned char`.
-@frozen
-public struct DarwinBoolean : ExpressibleByBooleanLiteral {
-  @usableFromInline var _value: UInt8
-
-  @_transparent
-  public init(_ value: Bool) {
-    self._value = value ? 1 : 0
-  }
-
-  /// The value of `self`, expressed as a `Bool`.
-  @_transparent
-  public var boolValue: Bool {
-    return _value != 0
-  }
-
-  /// Create an instance initialized to `value`.
-  @_transparent
-  public init(booleanLiteral value: Bool) {
-    self.init(value)
-  }
-}
-
-#if SWIFT_ENABLE_REFLECTION
-extension DarwinBoolean : CustomReflectable {
-  /// Returns a mirror that reflects `self`.
-  public var customMirror: Mirror {
-    return Mirror(reflecting: boolValue)
-  }
-}
-#endif
-
-@_unavailableInEmbedded
-extension DarwinBoolean : CustomStringConvertible {
-  /// A textual representation of `self`.
-  public var description: String {
-    return self.boolValue.description
-  }
-}
-
-extension DarwinBoolean : Equatable {
-  @_transparent
-  public static func ==(lhs: DarwinBoolean, rhs: DarwinBoolean) -> Bool {
-    return lhs.boolValue == rhs.boolValue
-  }
-}
-
-@_transparent
-public // COMPILER_INTRINSIC
-func _convertBoolToDarwinBoolean(_ x: Bool) -> DarwinBoolean {
-  return DarwinBoolean(x)
-}
-
-@_transparent
-public // COMPILER_INTRINSIC
-func _convertDarwinBooleanToBool(_ x: DarwinBoolean) -> Bool {
-  return x.boolValue
-}
-
-#endif
-
 //===----------------------------------------------------------------------===//
 // sys/errno.h
 //===----------------------------------------------------------------------===//
@@ -102,7 +31,7 @@ public var errno : Int32 {
 // stdio.h
 //===----------------------------------------------------------------------===//
 
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS) || os(FreeBSD) || os(PS4)
+#if os(FreeBSD) || os(PS4)
 public var stdin : UnsafeMutablePointer<FILE> {
   get {
     return __stdinp
@@ -145,17 +74,33 @@ public func snprintf(ptr: UnsafeMutablePointer<Int8>, _ len: Int, _ format: Unsa
 #endif
 
 #elseif os(OpenBSD)
-public var stdin: UnsafeMutablePointer<FILE> { return _swift_stdlib_stdin() }
-public var stdout: UnsafeMutablePointer<FILE> { return _swift_stdlib_stdout() }
-public var stderr: UnsafeMutablePointer<FILE> { return _swift_stdlib_stderr() }
+public var stdin: OpaquePointer { return OpaquePointer(_swift_stdlib_stdin()) }
+public var stdout: OpaquePointer { return OpaquePointer(_swift_stdlib_stdout()) }
+public var stderr: OpaquePointer { return OpaquePointer(_swift_stdlib_stderr()) }
 #elseif os(Windows)
-public var stdin: UnsafeMutablePointer<FILE> { return __acrt_iob_func(0) }
-public var stdout: UnsafeMutablePointer<FILE> { return __acrt_iob_func(1) }
-public var stderr: UnsafeMutablePointer<FILE> { return __acrt_iob_func(2) }
+public var stdin: UnsafeMutablePointer<FILE> {
+  return unsafe __acrt_iob_func(0)
+}
 
-public var STDIN_FILENO: Int32 { return _fileno(stdin) }
-public var STDOUT_FILENO: Int32 { return _fileno(stdout) }
-public var STDERR_FILENO: Int32 { return _fileno(stderr) }
+public var stdout: UnsafeMutablePointer<FILE> {
+  return unsafe __acrt_iob_func(1)
+}
+
+public var stderr: UnsafeMutablePointer<FILE> {
+  return unsafe __acrt_iob_func(2)
+}
+
+public var STDIN_FILENO: Int32 {
+  return unsafe _fileno(stdin)
+}
+
+public var STDOUT_FILENO: Int32 {
+  return unsafe _fileno(stdout)
+}
+
+public var STDERR_FILENO: Int32 {
+  return unsafe _fileno(stderr)
+}
 #endif
 
 
@@ -250,9 +195,6 @@ public var S_IFBLK: mode_t  { return mode_t(0o060000) }
 public var S_IFREG: mode_t  { return mode_t(0o100000) }
 public var S_IFLNK: mode_t  { return mode_t(0o120000) }
 public var S_IFSOCK: mode_t { return mode_t(0o140000) }
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS)
-public var S_IFWHT: mode_t  { return mode_t(0o160000) }
-#endif
 
 public var S_IRWXU: mode_t  { return mode_t(0o000700) }
 public var S_IRUSR: mode_t  { return mode_t(0o000400) }
@@ -272,13 +214,6 @@ public var S_IXOTH: mode_t  { return mode_t(0o000001) }
 public var S_ISUID: mode_t  { return mode_t(0o004000) }
 public var S_ISGID: mode_t  { return mode_t(0o002000) }
 public var S_ISVTX: mode_t  { return mode_t(0o001000) }
-
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS)
-public var S_ISTXT: mode_t  { return S_ISVTX }
-public var S_IREAD: mode_t  { return S_IRUSR }
-public var S_IWRITE: mode_t { return S_IWUSR }
-public var S_IEXEC: mode_t  { return S_IXUSR }
-#endif
 #endif
 
 //===----------------------------------------------------------------------===//
@@ -313,37 +248,16 @@ public func ioctl(
 // !os(Windows)
 #endif
 
-//===----------------------------------------------------------------------===//
-// unistd.h
-//===----------------------------------------------------------------------===//
-
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS)
-@available(*, unavailable, message: "Please use threads or posix_spawn*()")
-public func fork() -> Int32 {
-  fatalError("unavailable function can't be called")
-}
-
-@available(*, unavailable, message: "Please use threads or posix_spawn*()")
-public func vfork() -> Int32 {
-  fatalError("unavailable function can't be called")
-}
-#endif
-
 //===----------------------------------------------------------------------===//
 // signal.h
 //===----------------------------------------------------------------------===//
 
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS)
-public var SIG_DFL: sig_t? { return nil }
-public var SIG_IGN: sig_t { return unsafeBitCast(1, to: sig_t.self) }
-public var SIG_ERR: sig_t { return unsafeBitCast(-1, to: sig_t.self) }
-public var SIG_HOLD: sig_t { return unsafeBitCast(5, to: sig_t.self) }
-#elseif os(OpenBSD)
+#if os(OpenBSD) || os(FreeBSD)
 public var SIG_DFL: sig_t? { return nil }
 public var SIG_IGN: sig_t { return unsafeBitCast(1, to: sig_t.self) }
 public var SIG_ERR: sig_t { return unsafeBitCast(-1, to: sig_t.self) }
 public var SIG_HOLD: sig_t { return unsafeBitCast(3, to: sig_t.self) }
-#elseif os(Linux) || os(FreeBSD) || os(PS4) || os(Android) || os(Haiku)
+#elseif os(Linux) || os(PS4) || os(Android) || os(Haiku)
 #if !canImport(SwiftMusl)
 public typealias sighandler_t = __sighandler_t
 #endif
@@ -374,10 +288,10 @@ public var SIG_HOLD: sighandler_t {
 #elseif os(Windows)
 public var SIG_DFL: _crt_signal_t? { return nil }
 public var SIG_IGN: _crt_signal_t {
-  return unsafeBitCast(1, to: _crt_signal_t.self)
+  return unsafe unsafeBitCast(1, to: _crt_signal_t.self)
 }
 public var SIG_ERR: _crt_signal_t {
-  return unsafeBitCast(-1, to: _crt_signal_t.self)
+  return unsafe unsafeBitCast(-1, to: _crt_signal_t.self)
 }
 #elseif os(WASI)
 // No signals support on WASI yet, see https://github.com/WebAssembly/WASI/issues/166.
@@ -399,10 +313,7 @@ public typealias Semaphore = UnsafeMutablePointer<sem_t>
 
 /// The value returned by `sem_open()` in the case of failure.
 public var SEM_FAILED: Semaphore? {
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS)
-  // The value is ABI.  Value verified to be correct for OS X, iOS, watchOS, tvOS.
-  return Semaphore(bitPattern: -1)
-#elseif os(Linux) || os(FreeBSD) || os(OpenBSD) || os(PS4) || os(Android) || os(Cygwin) || os(Haiku) || os(WASI)
+#if os(Linux) || os(FreeBSD) || os(OpenBSD) || os(PS4) || os(Android) || os(Cygwin) || os(Haiku) || os(WASI)
   // The value is ABI.  Value verified to be correct on Glibc.
   return Semaphore(bitPattern: 0)
 #else
@@ -432,14 +343,14 @@ public func sem_open(
 // time.h
 //===----------------------------------------------------------------------===//
 
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS) || os(Linux)
+#if os(Linux)
 
 @available(SwiftStdlib 5.7, *)
 extension timespec {
   @available(SwiftStdlib 5.7, *)
   public init(_ duration: Duration) {
     let comps = duration.components
-    self.init(tv_sec: Int(comps.seconds),
+    self.init(tv_sec: time_t(comps.seconds),
               tv_nsec: Int(comps.attoseconds / 1_000_000_000))
   }
 }
@@ -458,14 +369,18 @@ extension timeval {
   public init(_ duration: Duration) {
     let comps = duration.components
 #if os(Linux)
-  // Linux platforms define timeval as Int/Int
-  self.init(tv_sec: Int(comps.seconds),
-              tv_usec: Int(comps.attoseconds / 1_000_000_000_000))
+    // Linux platforms define timeval as Int/Int, except on 32-bit platforms
+    // where _TIME_BITS=64 is defined. Abuse time_t as an alias for the correct
+    // suseconds_t type, as it is not an alias to the 64-bit type on 32-bit
+    // platforms.
+    typealias _Seconds = time_t
+    typealias _Microseconds = time_t
 #else
-    // Darwin platforms define timeval as Int/Int32
-    self.init(tv_sec: Int(comps.seconds),
-              tv_usec: Int32(comps.attoseconds / 1_000_000_000_000))
+    typealias _Seconds = Int
+    typealias _Microseconds = Int // note: was Int32 in release/6.1
 #endif
+    self.init(tv_sec: _Seconds(comps.seconds),
+              tv_usec: _Microseconds(comps.attoseconds / 1_000_000_000_000))
   }
 }
 
@@ -485,7 +400,7 @@ extension Duration {
 
 // Some platforms don't have `extern char** environ` imported from C.
 #if SWIFT_STDLIB_HAS_ENVIRON
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS) || os(FreeBSD) || os(OpenBSD) || os(PS4)
+#if os(FreeBSD) || os(OpenBSD) || os(PS4)
 public var environ: UnsafeMutablePointer<UnsafeMutablePointer<CChar>?> {
   return _swift_stdlib_getEnviron()
 }
@@ -495,3 +410,9 @@ public var environ: UnsafeMutablePointer<UnsafeMutablePointer<CChar>?> {
 }
 #endif
 #endif // SWIFT_STDLIB_HAS_ENVIRON
+
+#if os(FreeBSD)
+@inlinable public func inet_pton(_ af: CInt, _ src: UnsafePointer<CChar>!, _ dst: UnsafeMutableRawPointer!) -> CInt {
+  __inet_pton(af, src, dst)
+}
+#endif
diff --git a/stdlib/public/Platform/README.md b/stdlib/public/Platform/README.md
index 5404201cf0701..d6845fc34b3c9 100644
--- a/stdlib/public/Platform/README.md
+++ b/stdlib/public/Platform/README.md
@@ -1,11 +1,10 @@
-This directory holds the Swift Standard Library's Darwin and Glibc Module,
-comprised of
+This directory holds the Swift Standard Library's Glibc Module, comprised of
 
 - The *overlay* library, which amends some APIs imported from Clang module.
-- Glibc only: The clang [module map] which specifies which headers need to
-  be imported from Glibc for bare minimum functionality.
+- The clang [module map] which specifies which headers need to be imported
+  from Glibc for bare minimum functionality.
 
-Note: On Darwin platforms, we assume clang [module map] is already installed
-in the system SDK.
+Note: Darwin platforms provide their own overlays and module maps in the
+system SDK.
 
 [module map]: http://clang.llvm.org/docs/Modules.html
diff --git a/stdlib/public/Platform/SwiftGlibc.h.gyb b/stdlib/public/Platform/SwiftGlibc.h.gyb
index 61d054e09b049..10e8283ba77f3 100644
--- a/stdlib/public/Platform/SwiftGlibc.h.gyb
+++ b/stdlib/public/Platform/SwiftGlibc.h.gyb
@@ -57,6 +57,7 @@ headers = [
   'nl_types.h',
   'poll.h',
   'pthread.h',
+  'pthread_np.h',
   'pwd.h',
   'regex.h',
   'sched.h',
@@ -65,6 +66,7 @@ headers = [
   'spawn.h',
   'strings.h',
   'sys/event.h',
+  'sys/extattr.h',
   'sys/file.h',
   'sys/inotify.h',
   'sys/ioctl.h',
@@ -84,6 +86,7 @@ headers = [
   'sys/times.h',
   'sys/types.h',
   'sys/uio.h',
+  'sys/umtx.h',
   'sys/un.h',
   'sys/user.h',
   'sys/utsname.h',
diff --git a/stdlib/public/Platform/TiocConstants.swift b/stdlib/public/Platform/TiocConstants.swift
index 9510315d19908..d9df9acb4a2d4 100644
--- a/stdlib/public/Platform/TiocConstants.swift
+++ b/stdlib/public/Platform/TiocConstants.swift
@@ -10,10 +10,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Tty ioctl request constants, needed only on Darwin and FreeBSD.
+// Tty ioctl request constants, needed only on FreeBSD.
 
 // Constants available on all platforms, also available on Linux.
-#if os(macOS) || os(iOS) || os(tvOS) || os(watchOS) || os(visionOS) || os(FreeBSD) || os(Haiku)
+#if os(FreeBSD) || os(Haiku)
 
 /// Set exclusive use of tty.
 public var TIOCEXCL: UInt { return 0x2000740d }
@@ -114,45 +114,6 @@ public var TIOCGLTC: UInt { return 0x40067474 }
 #endif
 
 
-// Darwin only constants, also available on Linux.
-#if os(macOS) || os(iOS) || os(tvOS) || os(watchOS) || os(visionOS)
-
-/// Get termios struct.
-public var TIOCGETA: UInt { return 0x40487413 }
-/// Set termios struct.
-public var TIOCSETA: UInt { return 0x80487414 }
-/// Drain output, set.
-public var TIOCSETAW: UInt { return 0x80487415 }
-/// Drn out, fls in, set.
-public var TIOCSETAF: UInt { return 0x80487416 }
-/// Pty: generate signal.
-public var TIOCSIG: UInt { return 0x2000745f }
-/// Get modem control state.
-public var TIOCMODG: UInt { return 0x40047403 }
-/// Set modem control state.
-public var TIOCMODS: UInt { return 0x80047404 }
-/// Internal input VSTART.
-public var TIOCIXON: UInt { return 0x20007481 }
-/// Internal input VSTOP.
-public var TIOCIXOFF: UInt { return 0x20007480 }
-/// Remote input editing.
-public var TIOCREMOTE: UInt { return 0x80047469 }
-/// 4.2 compatibility.
-public var TIOCSCONS: UInt { return 0x20007463 }
-/// Enable/get timestamp of last DCd rise.
-public var TIOCDCDTIMESTAMP: UInt { return 0x40107458 }
-/// Download microcode to DSI Softmodem.
-public var TIOCDSIMICROCODE: UInt { return 0x20007455 }
-/// Grantpt(3).
-public var TIOCPTYGRANT: UInt { return 0x20007454 }
-/// Ptsname(3).
-public var TIOCPTYGNAME: UInt { return 0x40807453 }
-/// Unlockpt(3).
-public var TIOCPTYUNLK: UInt { return 0x20007452 }
-
-#endif
-
-
 // FreeBSD specific values and constants available only on FreeBSD.
 #if os(FreeBSD)
 
diff --git a/stdlib/public/Platform/glibc.modulemap.gyb b/stdlib/public/Platform/glibc.modulemap.gyb
index af25d0cf93ad1..221f0d00b6598 100644
--- a/stdlib/public/Platform/glibc.modulemap.gyb
+++ b/stdlib/public/Platform/glibc.modulemap.gyb
@@ -19,7 +19,7 @@
 /// It's not named just Glibc so that it doesn't conflict in the event of a
 /// future official glibc modulemap.
 module SwiftGlibc [system] {
-% if CMAKE_SDK in ["LINUX", "OPENBSD"]:
+% if CMAKE_SDK in ["LINUX", "FREEBSD", "OPENBSD"]:
       link "m"
 % end
 % if CMAKE_SDK in ["LINUX", "FREEBSD", "OPENBSD", "CYGWIN"]:
diff --git a/stdlib/public/Platform/tgmath.swift.gyb b/stdlib/public/Platform/tgmath.swift.gyb
index 1680044d4d59f..f5f83cd87bd89 100644
--- a/stdlib/public/Platform/tgmath.swift.gyb
+++ b/stdlib/public/Platform/tgmath.swift.gyb
@@ -222,7 +222,7 @@ def TypedBinaryFunctions():
 // Note these do not have a corresponding LLVM intrinsic
 % for T, CT, f, ufunc in TypedUnaryFunctions():
 %  if T == 'Float80':
-#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux) && !(os(macOS) || os(iOS) || os(watchOS) || os(tvOS))))
+#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux)))
 %  end
 @_transparent
 public func ${ufunc}(_ x: ${T}) -> ${T} {
@@ -234,23 +234,6 @@ public func ${ufunc}(_ x: ${T}) -> ${T} {
 
 % end
 
-#if os(macOS) || os(iOS) || os(tvOS) || os(watchOS) || os(visionOS)
-// Unary intrinsic functions
-// Note these have a corresponding LLVM intrinsic
-% for T, ufunc in TypedUnaryIntrinsicFunctions():
-%  if T == 'Float80':
-#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux) && !(os(macOS) || os(iOS) || os(watchOS) || os(tvOS))))
-%  end
-@_transparent
-public func ${ufunc}(_ x: ${T}) -> ${T} {
-  return _${ufunc}(x)
-}
-%  if T == 'Float80':
-#endif
-%  end
-
-% end
-#else
 // FIXME: As of now, we cannot declare 64-bit (Double/CDouble) overlays here.
 // Since CoreFoundation also exports libc functions, they will conflict with
 // Swift overlays when building Foundation. For now, just like normal
@@ -258,7 +241,7 @@ public func ${ufunc}(_ x: ${T}) -> ${T} {
 % for ufunc in UnaryIntrinsicFunctions:
 %  for T, CT, f in OverlayFloatTypes():
 %   if T == 'Float80':
-#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux) && !(os(macOS) || os(iOS) || os(watchOS) || os(tvOS))))
+#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux)))
 %   end
 @_transparent
 public func ${ufunc}(_ x: ${T}) -> ${T} {
@@ -269,13 +252,12 @@ public func ${ufunc}(_ x: ${T}) -> ${T} {
 %   end
 %  end
 % end
-#endif
 
 // Binary functions
 
 % for T, CT, f, bfunc in TypedBinaryFunctions():
 %  if T == 'Float80':
-#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux) && !(os(macOS) || os(iOS) || os(watchOS) || os(tvOS))))
+#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux)))
 %  end
 @_transparent
 public func ${bfunc}(_ lhs: ${T}, _ rhs: ${T}) -> ${T} {
@@ -290,7 +272,7 @@ public func ${bfunc}(_ lhs: ${T}, _ rhs: ${T}) -> ${T} {
 % # This is AllFloatTypes not OverlayFloatTypes because of the tuple return.
 % for T, CT, f in AllFloatTypes():
 %  if T == 'Float80':
-#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || os(OpenBSD) || ($Embedded && !os(Linux) && !(os(macOS) || os(iOS) || os(watchOS) || os(tvOS))))
+#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || os(OpenBSD) || ($Embedded && !os(Linux)))
 %  else:
 //  lgamma not available on Windows, apparently?
 #if !os(Windows)
@@ -308,12 +290,12 @@ public func lgamma(_ x: ${T}) -> (${T}, Int) {
 % # This is AllFloatTypes not OverlayFloatTypes because of the tuple return.
 % for T, CT, f in AllFloatTypes():
 %  if T == 'Float80':
-#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux) && !(os(macOS) || os(iOS) || os(watchOS) || os(tvOS))))
+#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux)))
 %  end
 @_transparent
 public func remquo(_ x: ${T}, _ y: ${T}) -> (${T}, Int) {
   var quo = Int32(0)
-  let rem = remquo${f}(${CT}(x), ${CT}(y), &quo)
+  let rem = unsafe remquo${f}(${CT}(x), ${CT}(y), &quo)
   return (${T}(rem), Int(quo))
 }
 %  if T == 'Float80':
@@ -324,14 +306,14 @@ public func remquo(_ x: ${T}, _ y: ${T}) -> (${T}, Int) {
 
 % for T, CT, f in OverlayFloatTypes():
 %  if T == 'Float80':
-#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux) && !(os(macOS) || os(iOS) || os(watchOS) || os(tvOS))))
+#if (arch(i386) || arch(x86_64)) && !(os(Windows) || os(Android) || ($Embedded && !os(Linux)))
 %  end
 @available(swift, deprecated: 4.2/*, obsoleted: 5.1*/, message:
            "use ${T}(nan: ${T}.RawSignificand).")
 @_transparent
 @_unavailableInEmbedded
 public func nan(_ tag: String) -> ${T} {
-  return ${T}(nan${f}(tag))
+  return ${T}(unsafe nan${f}(tag))
 }
 %  if T == 'Float80':
 #endif
diff --git a/stdlib/public/Platform/ucrt.modulemap b/stdlib/public/Platform/ucrt.modulemap
index f57d9e62b3131..3c16971b33ca4 100644
--- a/stdlib/public/Platform/ucrt.modulemap
+++ b/stdlib/public/Platform/ucrt.modulemap
@@ -12,36 +12,46 @@
 
 // The following modules have to be standalone top-level modules to deal with
 // version 10.0.26100 of the Windows SDK.
-module _malloc [system] [no_undeclared_includes] {
+module _complex [system] [no_undeclared_includes] {
   use corecrt
-  header "malloc.h"
+  use std
+  header "complex.h"
   export *
 }
 
-module _complex [system] [no_undeclared_includes] {
+module _fenv [system] [no_undeclared_includes] {
+  use _float
   use corecrt
-  use std
-  header "complex.h"
+  header "fenv.h"
+  export *
+}
+
+module _float [system] [no_undeclared_includes] {
+  use corecrt
+  header "float.h"
   export *
 }
 
-module _stddef [system] [no_undeclared_includes] {
-  header "stddef.h"
+module _malloc [system] [no_undeclared_includes] {
+  use corecrt
+  header "malloc.h"
   export *
 }
 
 module _stdlib [system] [no_undeclared_includes] {
   use corecrt
+  use vcruntime
   header "stdlib.h"
   export *
 }
 
 module ucrt [system] {
-  export _malloc
 
   module C {
     export _complex
-    export _stddef
+    export _fenv
+    export _float
+    export _malloc
     export _stdlib
 
     module ctype {
@@ -50,7 +60,7 @@ module ucrt [system] {
     }
 
     module errno {
-      header "errno.h"
+      textual header "errno.h"
       export *
     }
 
@@ -74,6 +84,11 @@ module ucrt [system] {
       export *
     }
 
+    module malloc {
+      header "malloc.h"
+      export *
+    }
+
     module math {
       header "math.h"
       export *
@@ -84,6 +99,16 @@ module ucrt [system] {
       export *
     }
 
+    module stdalign {
+      header "stdalign.h"
+      export  *
+    }
+
+    module stddef {
+      textual header "stddef.h"
+      export *
+    }
+
     module stdio {
       header "stdio.h"
       export *
@@ -101,6 +126,11 @@ module ucrt [system] {
       export *
     }
 
+    module stdnoreturn {
+      textual header "stdnoreturn.h"
+      export *
+    }
+
     module string {
       header "string.h"
       export *
@@ -187,8 +217,14 @@ module corecrt [system] {
     export *
   }
 
+  module direct {
+    header "corecrt_wdirect.h"
+    export *
+  }
+
   module io {
     header "corecrt_io.h"
+    header "corecrt_wio.h"
     export *
   }
 
@@ -202,11 +238,36 @@ module corecrt [system] {
     export *
   }
 
+  module memory {
+    header "corecrt_memory.h"
+    export *
+  }
+
+  module memcpy {
+    header "corecrt_memcpy_s.h"
+    export *
+  }
+
+  module process {
+    header "corecrt_wprocess.h"
+    export *
+  }
+
+  module search {
+    header "corecrt_search.h"
+    export *
+  }
+
   module share {
     header "corecrt_share.h"
     export *
   }
 
+  module ctype {
+    header "corecrt_wctype.h"
+    export *
+  }
+
   module stdio {
     header "corecrt_wstdio.h"
     export *
@@ -227,4 +288,3 @@ module corecrt [system] {
     export *
   }
 }
-
diff --git a/stdlib/public/Platform/vcruntime.modulemap b/stdlib/public/Platform/vcruntime.modulemap
index 564c832dcc12b..4a961bcede91a 100644
--- a/stdlib/public/Platform/vcruntime.modulemap
+++ b/stdlib/public/Platform/vcruntime.modulemap
@@ -100,15 +100,45 @@ module vcruntime [system] {
 
   header "vcruntime.h"
 
+  module iso646 {
+    header "iso646.h"
+    export *
+  }
+
+  module limits {
+    header "limits.h"
+    export *
+  }
+
   module setjmp {
     header "setjmp.h"
     export *
   }
 
+  module stdarg {
+    header "stdarg.h"
+    export *
+  }
+
+  module stdbool {
+    header "stdbool.h"
+    export  *
+  }
+
   module stdint {
     header "stdint.h"
     export *
   }
+
+  module string {
+    header "vcruntime_string.h"
+    export *
+  }
+
+  module vadefs {
+    header "vadefs.h"
+    export *
+  }
 }
 
 module std_config [system] {
@@ -727,6 +757,11 @@ module std [system] {
       export *
     }
 
+    explicit module xsmf_control {
+      header "xsmf_control.h"
+      export *
+    }
+
     explicit module xstring {
       header "xstring"
       export *
diff --git a/stdlib/public/Platform/winsdk.modulemap b/stdlib/public/Platform/winsdk.modulemap
deleted file mode 100644
index 7a0705da3130b..0000000000000
--- a/stdlib/public/Platform/winsdk.modulemap
+++ /dev/null
@@ -1,586 +0,0 @@
-//===--- WinSDK.modulemap -------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-module WinSDK [system] {
-  module WinSock2 {
-    header "WinSock2.h"
-    header "WS2tcpip.h"
-    header "MSWSock.h"
-    header "../shared/afunix.h"
-    export *
-
-    link "WS2_32.Lib"
-  }
-
-  module WinSock {
-    header "winsock.h"
-  }
-
-  module core {
-    module acl {
-      header "AclAPI.h"
-      export *
-    }
-
-    module com {
-      header "combaseapi.h"
-      export *
-    }
-
-    module compress {
-      header "compressapi.h"
-      export *
-    }
-
-    module console {
-      header "consoleapi.h"
-      header "consoleapi2.h"
-      header "consoleapi3.h"
-      export *
-    }
-
-    // api-ms-win-appmodel-runtime-l1
-    module appmodel {
-      header "appmodel.h"
-      export *
-    }
-
-    // api-ms-win-core-errhandling-l1-1-0.dll
-    module errhandling {
-      header "errhandlingapi.h"
-      export *
-    }
-
-    // api-ms-win-core-file-l1-1-0.dll
-    module file {
-      header "fileapi.h"
-      export *
-    }
-
-    // api-ms-win-core-handle-l1-1-0.dll
-    module handle {
-      header "handleapi.h"
-      export *
-    }
-
-    // api-ms-win-heapapi-l1-1-0.dll
-    module heap {
-      header "heapapi.h"
-      export *
-    }
-
-    // api-ms-win-core-interlocked-l1-1-0.dll
-    module interlocked {
-      header "interlockedapi.h"
-      export *
-    }
-
-    // iphlpapi.dll
-    module iphlp {
-      header "iphlpapi.h"
-      export *
-
-      link "iphlpapi.lib"
-    }
-
-    // api-ms-win-core-libloader-l1-1-0.dll
-    module libloader {
-      header "libloaderapi.h"
-      export *
-    }
-
-    // api-ms-win-core-memory-l1-1-0.dll
-    module memory {
-      header "memoryapi.h"
-      export *
-
-      link "OneCore.Lib"
-    }
-
-    // api-ms-win-core-namedpipe-l1-1-2-0.dll
-    module namedpipe {
-      header "namedpipeapi.h"
-      export *
-    }
-
-    // api-ms-win-core-Path-l1-0.dll
-    module path {
-      header "PathCch.h"
-      export *
-
-      link "pathcch.lib"
-    }
-
-    // api-ms-win-core-processthreads-l1-1-2.dll
-    module processthreads {
-      header "processthreadsapi.h"
-      export *
-    }
-
-    // api-ms-win-core-synch-l1-2-0.dll
-    module synch {
-      header "synchapi.h"
-      export *
-    }
-
-    // api-ms-win-core-sysinfo-l1-1-0.dll
-    module sysinfo {
-      header "sysinfoapi.h"
-      export *
-    }
-
-    // api-ms-win-core-timezone-l1-1-0.dll
-    module timezone {
-      header "timezoneapi.h"
-      export *
-    }
-
-    // api-ms-win-core-version-l1-1-0.dll
-    module version {
-      header "winver.h"
-      export *
-
-      link "Version.Lib"
-    }
-  }
-
-  module ActiveX {
-    header "OCIdl.h"
-    export *
-  }
-
-  module Controls {
-    module CommCtrl {
-      header "CommCtrl.h"
-      export *
-
-      link "ComCtl32.Lib"
-    }
-
-    module CommDlg {
-      header "commdlg.h"
-      export *
-
-      link "ComDlg32.Lib"
-    }
-  }
-
-  explicit module DirectX {
-    module Direct3D11 {
-      header "d3d11.h"
-      header "d3d11_1.h"
-      header "d3d11_2.h"
-      header "d3d11_3.h"
-      header "d3d11_4.h"
-      export *
-
-      link "d3d11.lib"
-      link "dxgi.lib"
-    }
-
-    module Direct3D12 {
-      header "d3d12.h"
-      export *
-
-      link "d3d12.lib"
-      link "dxgi.lib"
-    }
-
-    // FIXME(compnerd) DXGI is part of the Direct3D interfaces currently; we
-    // should split it out, but because it is part of the D3D11 interfaces, this
-    // separate module is meant to augment the uncovered portions only.
-    module _DXGI {
-      header "../shared/dxgi1_6.h"
-      header "dxgidebug.h"
-      export *
-
-      link "dxgi.lib"
-    }
-
-    module D3DCompiler {
-      header "d3dcompiler.h"
-      export *
-
-      link "d3dcompiler.lib"
-    }
-
-    module XAudio29 {
-      header "xaudio2.h"
-      header "xaudio2fx.h"
-      export *
-
-      link "xaudio2.lib"
-
-      requires cplusplus
-    }
-
-    // XInput 1.4 (Windows 10, XBox) is newer than the XInput 9.1.0 which was
-    // part of Vista.
-    module XInput14 {
-      header "Xinput.h"
-      export *
-
-      link "xinput.lib"
-    }
-    
-    module DirectInput8 {
-      header "dinput.h"
-      export *
-
-      link "dinput8.lib"
-    }
-
-    link "dxguid.lib"
-  }
-
-  // FIXME(compnerd) this is a hack for the HWND typedef for DbgHelp
-  module __DirectX {
-    header "directmanipulation.h"
-    export *
-  }
-
-  module DDE {
-    header "dde.h"
-    header "ddeml.h"
-    export *
-  }
-
-  module DFS {
-    header "LMDFS.h"
-    header "LM.h"
-    export *
-
-    link "NetAPI32.Lib"
-  }
-
-  module DWM {
-    header "dwmapi.h"
-    export *
-
-    link "dwmapi.lib"
-  }
-
-  module FCI {
-    header "fci.h"
-    export *
-
-    link "Cabinet.Lib"
-  }
-
-  module Internationalization {
-    module WinNLS {
-      header "winnls.h"
-      export *
-    }
-
-    module IMM {
-      header "immdev.h"
-      header "imm.h"
-      export *
-
-      link "Imm32.lib"
-    }
-  }
-
-  module LZ32 {
-    header "LZExpand.h"
-    export *
-
-    link "Lz32.Lib"
-  }
-
-  module Multimedia {
-    module DigitalVideo {
-      header "Digitalv.h"
-      export *
-    }
-
-    module Video {
-      header "Vfw.h"
-      export *
-
-      link "Vfw32.Lib"
-    }
-
-    header "mmeapi.h"
-    header "mmddk.h"
-    header "mmsystem.h"
-    header "mmiscapi.h"
-    header "timeapi.h"
-    header "joystickapi.h"
-    export *
-
-    link "WinMM.Lib"
-  }
-
-  module Networking {
-    header "winnetwk.h"
-    export *
-
-    link "Mpr.Lib"
-  }
-
-  module Security {
-    header "../shared/sddl.h"
-
-    module AuthZ {
-      header "AuthZ.h"
-      export *
-
-      link "AuthZ.Lib"
-    }
-
-    module SmartCard {
-      header "winscard.h"
-      export *
-
-      link "winscard.lib"
-    }
-
-    module WinCrypt {
-      header "wincrypt.h"
-      export *
-
-      link "Crypt32.Lib"
-    }
-  }
-
-  module Shell {
-    header "ShlObj.h"
-    export *
-  }
-
-  module AppNotify {
-    header "appnotify.h"
-    export *
-
-    link "appnotify.lib"
-  }
-
-  module ShellAPI {
-    header "shellapi.h"
-    header "Shlwapi.h"
-    export *
-
-    link "shell32.lib"
-    link "ShLwApi.Lib"
-  }
-
-  module ShellCore {
-    header "ShellScalingApi.h"
-    export *
-
-    link "shcore.lib"
-  }
-
-  module System {
-    module DbgHelp {
-      header "DbgHelp.h"
-      export *
-
-      link "DbgHelp.Lib"
-    }
-
-    module IOCTL {
-      header "winioctl.h"
-      export *
-    }
-
-    module MCX {
-      header "mcx.h"
-      export *
-    }
-  }
-
-  module OLE {
-    header "ole2.h"
-    export *
-  }
-
-  module OLE32 {
-    header "oaidl.h"
-    header "oleauto.h"
-    export *
-
-    link "OleAut32.Lib"
-  }
-
-  module Performance {
-    module PerfLib {
-      header "perflib.h"
-      export *
-
-      link "AdvAPI32.Lib"
-    }
-
-    module PDH {
-      header "Pdh.h"
-      export *
-
-      link "Pdh.Lib"
-    }
-
-    header "winperf.h"
-    export *
-  }
-
-  module Printing {
-    header "winspool.h"
-    export *
-
-    link "WinSpool.Lib"
-  }
-
-  module PSAPI {
-    header "Psapi.h"
-    export *
-
-    link "psapi.lib"
-  }
-
-  module RichEdit {
-    header "Richedit.h"
-    export *
-  }
-
-  module Sensors {
-    header "sensors.h"
-    header "SensorsApi.h"
-    export *
-
-    link "sensorsapi.lib"
-  }
-
-  module ToolHelp {
-    header "TlHelp32.h"
-    export *
-
-    link "kernel32.Lib"
-  }
-
-  module UI {
-    module XAML {
-      module Hosting {
-        header "windows.ui.xaml.hosting.desktopwindowxamlsource.h"
-        export *
-      }
-    }
-  }
-
-  module URLMonikers {
-    header "urlmon.h"
-    export *
-    link "Urlmon.Lib"
-  }
-
-  module User {
-    header "WinUser.h"
-    export *
-    link "User32.Lib"
-  }
-
-  module UserEnv {
-    header "UserEnv.h"
-    export *
-    link "UserEnv.Lib"
-  }
-
-  module WER {
-    header "WerApi.h"
-    export *
-  }
-
-  module WIC {
-    header "wincodec.h"
-    export *
-
-    link "windowscodecs.lib"
-  }
-
-  module WinBase {
-    header "winbase.h"
-    export *
-  }
-
-  module WinCred {
-    header "wincred.h"
-    export *
-
-    link "AdvAPI32.lib"
-  }
-
-  module WinDNS {
-    header "WinDNS.h"
-    export *
-
-    link "DnsAPI.Lib"
-  }
-
-  module WinGDI {
-    header "wingdi.h"
-    export *
-
-    link "Gdi32.Lib"
-  }
-
-  module WinNT {
-    header "winnt.h"
-    export *
-  }
-
-  module WinReg {
-    header "winreg.h"
-    export *
-
-    link "AdvAPI32.Lib"
-  }
-
-  module WinRPC {
-    header "../shared/rpc.h"
-    header "../shared/rpcndr.h"
-    export *
-
-    link "RpcRT4.Lib"
-  }
-
-  module WinSVC {
-    header "winsvc.h"
-    export *
-
-    link "AdvAPI32.Lib"
-  }
-
-  module WinSafer {
-    header "winsafer.h"
-    export *
-
-    link "AdvAPI32.Lib"
-  }
-  
-  module WinUSB {
-    header "winusb.h"
-    export *
-    
-    link "winusb.lib"
-  }
-
-  // TODO(compnerd) does it make sense to implicitly export this API surface?
-  // It seems to be meant for device drivers.
-  module WLANAPI {
-    header "wlanapi.h"
-    header "wlanihv.h"
-    header "wlclient.h"
-
-    link "wlanapi.lib"
-  }
-}
-
diff --git a/stdlib/public/Platform/winsdk_shared.modulemap b/stdlib/public/Platform/winsdk_shared.modulemap
new file mode 100644
index 0000000000000..5ccb8de8c9b10
--- /dev/null
+++ b/stdlib/public/Platform/winsdk_shared.modulemap
@@ -0,0 +1,21 @@
+//===--- WinSDK_Shared.modulemap ------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+module _GUIDDef {
+  header "guiddef.h"
+  export *
+}
+
+module WinAPIFamily {
+  header "winapifamily.h"
+  export *
+}
diff --git a/stdlib/public/Platform/winsdk_um.modulemap b/stdlib/public/Platform/winsdk_um.modulemap
new file mode 100644
index 0000000000000..a7e12f0a08390
--- /dev/null
+++ b/stdlib/public/Platform/winsdk_um.modulemap
@@ -0,0 +1,600 @@
+//===--- WinSDK_UM.modulemap ----------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+module WinSDK [system] {
+  module WinSock2 {
+    header "WinSock2.h"
+    header "WS2tcpip.h"
+    header "MSWSock.h"
+    header "../shared/afunix.h"
+    export *
+
+    link "WS2_32.Lib"
+  }
+
+  module WinSock {
+    header "winsock.h"
+  }
+
+  module core {
+    module acl {
+      header "AclAPI.h"
+      export *
+    }
+
+    module com {
+      header "combaseapi.h"
+      export *
+    }
+
+    module compress {
+      header "compressapi.h"
+      export *
+    }
+
+    module console {
+      header "consoleapi.h"
+      header "consoleapi2.h"
+      header "consoleapi3.h"
+      export *
+    }
+
+    // api-ms-win-appmodel-runtime-l1
+    module appmodel {
+      header "appmodel.h"
+      export *
+    }
+
+    // api-ms-win-core-errhandling-l1-1-0.dll
+    module errhandling {
+      header "errhandlingapi.h"
+      export *
+    }
+
+    // api-ms-win-core-file-l1-1-0.dll
+    module file {
+      header "fileapi.h"
+      export *
+    }
+
+    // api-ms-win-core-handle-l1-1-0.dll
+    module handle {
+      header "handleapi.h"
+      export *
+    }
+
+    // api-ms-win-heapapi-l1-1-0.dll
+    module heap {
+      header "heapapi.h"
+      export *
+    }
+
+    // api-ms-win-core-interlocked-l1-1-0.dll
+    module interlocked {
+      header "interlockedapi.h"
+      export *
+    }
+
+    // iphlpapi.dll
+    module iphlp {
+      header "iphlpapi.h"
+      export *
+
+      link "iphlpapi.lib"
+    }
+
+    // api-ms-win-core-libloader-l1-1-0.dll
+    module libloader {
+      header "libloaderapi.h"
+      export *
+    }
+
+    // api-ms-win-core-memory-l1-1-0.dll
+    module memory {
+      header "memoryapi.h"
+      export *
+
+      link "OneCore.Lib"
+    }
+
+    // api-ms-win-core-namedpipe-l1-1-2-0.dll
+    module namedpipe {
+      header "namedpipeapi.h"
+      export *
+    }
+
+    // api-ms-win-core-Path-l1-0.dll
+    module path {
+      header "PathCch.h"
+      export *
+
+      link "pathcch.lib"
+    }
+
+    // api-ms-win-core-processthreads-l1-1-2.dll
+    module processthreads {
+      header "processthreadsapi.h"
+      export *
+    }
+
+    // api-ms-win-core-synch-l1-2-0.dll
+    module synch {
+      header "synchapi.h"
+      export *
+    }
+
+    // api-ms-win-core-sysinfo-l1-1-0.dll
+    module sysinfo {
+      header "sysinfoapi.h"
+      export *
+    }
+
+    // api-ms-win-core-timezone-l1-1-0.dll
+    module timezone {
+      header "timezoneapi.h"
+      export *
+    }
+
+    // api-ms-win-core-version-l1-1-0.dll
+    module version {
+      header "winver.h"
+      export *
+
+      link "Version.Lib"
+    }
+  }
+
+  module ActiveX {
+    header "OCIdl.h"
+    export *
+  }
+
+  module Controls {
+    module CommCtrl {
+      header "CommCtrl.h"
+      export *
+
+      link "ComCtl32.Lib"
+    }
+
+    module CommDlg {
+      header "commdlg.h"
+      export *
+
+      link "ComDlg32.Lib"
+    }
+  }
+
+  explicit module DirectX {
+    module Direct3D11 {
+      header "d3d11.h"
+      header "d3d11_1.h"
+      header "d3d11_2.h"
+      header "d3d11_3.h"
+      header "d3d11_4.h"
+      export *
+
+      link "d3d11.lib"
+      link "dxgi.lib"
+    }
+
+    module Direct3D12 {
+      header "d3d12.h"
+      export *
+
+      link "d3d12.lib"
+      link "dxgi.lib"
+    }
+
+    // FIXME(compnerd) DXGI is part of the Direct3D interfaces currently; we
+    // should split it out, but because it is part of the D3D11 interfaces, this
+    // separate module is meant to augment the uncovered portions only.
+    module _DXGI {
+      header "../shared/dxgi1_6.h"
+      header "dxgidebug.h"
+      export *
+
+      link "dxgi.lib"
+    }
+
+    module D3DCompiler {
+      header "d3dcompiler.h"
+      export *
+
+      link "d3dcompiler.lib"
+    }
+
+    module XAudio29 {
+      header "xaudio2.h"
+      header "xaudio2fx.h"
+      export *
+
+      link "xaudio2.lib"
+
+      requires cplusplus
+    }
+
+    // XInput 1.4 (Windows 10, XBox) is newer than the XInput 9.1.0 which was
+    // part of Vista.
+    module XInput14 {
+      header "Xinput.h"
+      export *
+
+      link "xinput.lib"
+    }
+    
+    module DirectInput8 {
+      header "dinput.h"
+      export *
+
+      link "dinput8.lib"
+    }
+
+    link "dxguid.lib"
+  }
+
+  // FIXME(compnerd) this is a hack for the HWND typedef for DbgHelp
+  module __DirectX {
+    header "directmanipulation.h"
+    export *
+  }
+
+  module DDE {
+    header "dde.h"
+    header "ddeml.h"
+    export *
+  }
+
+  module DFS {
+    header "LMDFS.h"
+    header "LM.h"
+    export *
+
+    link "NetAPI32.Lib"
+  }
+
+  module DWM {
+    header "dwmapi.h"
+    export *
+
+    link "dwmapi.lib"
+  }
+
+  module FCI {
+    header "fci.h"
+    export *
+
+    link "Cabinet.Lib"
+  }
+
+  explicit module GDIPlus {
+    header "gdiplus.h"
+    export *
+
+    link "gdiplus.lib"
+
+    requires cplusplus
+  }
+
+  module Internationalization {
+    module WinNLS {
+      header "winnls.h"
+      export *
+    }
+
+    module IMM {
+      header "immdev.h"
+      header "imm.h"
+      export *
+
+      link "Imm32.lib"
+    }
+  }
+
+  module LZ32 {
+    header "LZExpand.h"
+    export *
+
+    link "Lz32.Lib"
+  }
+
+  module Multimedia {
+    module DigitalVideo {
+      header "Digitalv.h"
+      export *
+    }
+
+    module Video {
+      header "Vfw.h"
+      export *
+
+      link "Vfw32.Lib"
+    }
+
+    header "mmeapi.h"
+    header "mmddk.h"
+    header "mmsystem.h"
+    header "mmiscapi.h"
+    header "timeapi.h"
+    header "joystickapi.h"
+    export *
+
+    link "WinMM.Lib"
+  }
+
+  module Networking {
+    header "winnetwk.h"
+    export *
+
+    link "Mpr.Lib"
+  }
+
+  module NTAPI {
+    header "winternl.h"
+    export *
+  }
+
+  module Security {
+    header "../shared/sddl.h"
+
+    module AuthZ {
+      header "AuthZ.h"
+      export *
+
+      link "AuthZ.Lib"
+    }
+
+    module SmartCard {
+      header "winscard.h"
+      export *
+
+      link "winscard.lib"
+    }
+
+    module WinCrypt {
+      header "wincrypt.h"
+      export *
+
+      link "Crypt32.Lib"
+    }
+  }
+
+  module Shell {
+    header "ShlObj.h"
+    export *
+  }
+
+  module AppNotify {
+    header "appnotify.h"
+    export *
+
+    link "appnotify.lib"
+  }
+
+  module ShellAPI {
+    header "shellapi.h"
+    header "Shlwapi.h"
+    export *
+
+    link "shell32.lib"
+    link "ShLwApi.Lib"
+  }
+
+  module ShellCore {
+    header "ShellScalingApi.h"
+    export *
+
+    link "shcore.lib"
+  }
+
+  module System {
+    module DbgHelp {
+      header "DbgHelp.h"
+      export *
+
+      link "DbgHelp.Lib"
+    }
+
+    module IOCTL {
+      header "winioctl.h"
+      export *
+    }
+
+    module MCX {
+      header "mcx.h"
+      export *
+    }
+  }
+
+  module OLE {
+    header "ole2.h"
+    export *
+  }
+
+  module OLE32 {
+    header "oaidl.h"
+    header "oleauto.h"
+    export *
+
+    link "OleAut32.Lib"
+  }
+
+  module Performance {
+    module PerfLib {
+      header "perflib.h"
+      export *
+
+      link "AdvAPI32.Lib"
+    }
+
+    module PDH {
+      header "Pdh.h"
+      export *
+
+      link "Pdh.Lib"
+    }
+
+    header "winperf.h"
+    export *
+  }
+
+  module Printing {
+    header "winspool.h"
+    export *
+
+    link "WinSpool.Lib"
+  }
+
+  module PSAPI {
+    header "Psapi.h"
+    export *
+
+    link "psapi.lib"
+  }
+
+  module RichEdit {
+    header "Richedit.h"
+    export *
+  }
+
+  module Sensors {
+    header "sensors.h"
+    header "SensorsApi.h"
+    export *
+
+    link "sensorsapi.lib"
+  }
+
+  module ToolHelp {
+    header "TlHelp32.h"
+    export *
+
+    link "kernel32.Lib"
+  }
+
+  module UI {
+    module XAML {
+      module Hosting {
+        header "windows.ui.xaml.hosting.desktopwindowxamlsource.h"
+        export *
+      }
+    }
+  }
+
+  module URLMonikers {
+    header "urlmon.h"
+    export *
+    link "Urlmon.Lib"
+  }
+
+  module User {
+    header "WinUser.h"
+    export *
+    link "User32.Lib"
+  }
+
+  module UserEnv {
+    header "UserEnv.h"
+    export *
+    link "UserEnv.Lib"
+  }
+
+  module WER {
+    header "WerApi.h"
+    export *
+  }
+
+  module WIC {
+    header "wincodec.h"
+    export *
+
+    link "windowscodecs.lib"
+  }
+
+  module WinBase {
+    header "winbase.h"
+    export *
+  }
+
+  module WinCred {
+    header "wincred.h"
+    export *
+
+    link "AdvAPI32.lib"
+  }
+
+  module WinDNS {
+    header "WinDNS.h"
+    export *
+
+    link "DnsAPI.Lib"
+  }
+
+  module WinGDI {
+    header "wingdi.h"
+    export *
+
+    link "Gdi32.Lib"
+  }
+
+  module WinNT {
+    header "winnt.h"
+    export *
+  }
+
+  module WinReg {
+    header "winreg.h"
+    export *
+
+    link "AdvAPI32.Lib"
+  }
+
+  module WinRPC {
+    header "../shared/rpc.h"
+    header "../shared/rpcndr.h"
+    export *
+
+    link "RpcRT4.Lib"
+  }
+
+  module WinSVC {
+    header "winsvc.h"
+    export *
+
+    link "AdvAPI32.Lib"
+  }
+
+  module WinSafer {
+    header "winsafer.h"
+    export *
+
+    link "AdvAPI32.Lib"
+  }
+  
+  module WinUSB {
+    header "winusb.h"
+    export *
+    
+    link "winusb.lib"
+  }
+
+  // TODO(compnerd) does it make sense to implicitly export this API surface?
+  // It seems to be meant for device drivers.
+  module WLANAPI {
+    header "wlanapi.h"
+    header "wlanihv.h"
+    header "wlclient.h"
+
+    link "wlanapi.lib"
+  }
+}
+
diff --git a/stdlib/public/RemoteInspection/TypeLowering.cpp b/stdlib/public/RemoteInspection/TypeLowering.cpp
index cb191049b898e..230c5bb95d529 100644
--- a/stdlib/public/RemoteInspection/TypeLowering.cpp
+++ b/stdlib/public/RemoteInspection/TypeLowering.cpp
@@ -408,8 +408,7 @@ bool RecordTypeInfo::readExtraInhabitantIndex(remote::MemoryReader &reader,
       [](const FieldInfo &lhs, const FieldInfo &rhs) {
         return lhs.TI.getNumExtraInhabitants() < rhs.TI.getNumExtraInhabitants();
       });
-    auto fieldAddress = remote::RemoteAddress(address.getAddressData()
-                                              + mostCapaciousField->Offset);
+    auto fieldAddress = address + mostCapaciousField->Offset;
     return mostCapaciousField->TI.readExtraInhabitantIndex(
       reader, fieldAddress, extraInhabitantIndex);
   }
@@ -1154,12 +1153,19 @@ class ExistentialTypeInfoBuilder {
   TypeConverter &TC;
   std::vector<const TypeRef *> Protocols;
   const TypeRef *Superclass = nullptr;
+  remote::RemoteAbsolutePointer Shape;
   ExistentialTypeRepresentation Representation;
   ReferenceCounting Refcounting;
   bool ObjC;
   unsigned WitnessTableCount;
   bool Invalid;
 
+  void markInvalid(const char *msg, const TypeRef *TR = nullptr) {
+    Invalid = true;
+    DEBUG_LOG(fprintf(stderr, "%s\n", msg); if (TR) TR->dump());
+    TC.setError(msg, TR);
+  }
+
   bool isSingleError() const {
     // If we changed representation, it means we added a
     // superclass constraint or an AnyObject member.
@@ -1191,8 +1197,7 @@ class ExistentialTypeInfoBuilder {
       auto *NTD = dyn_cast<NominalTypeRef>(P);
       auto *OP = dyn_cast<ObjCProtocolTypeRef>(P);
       if (!NTD && !OP) {
-        DEBUG_LOG(fprintf(stderr, "Bad protocol: "); P->dump())
-        Invalid = true;
+        markInvalid("bad protocol", P);
         continue;
       }
 
@@ -1204,8 +1209,7 @@ class ExistentialTypeInfoBuilder {
 
       auto FD = TC.getBuilder().getFieldDescriptor(P);
       if (FD == nullptr) {
-        DEBUG_LOG(fprintf(stderr, "No field descriptor: "); P->dump())
-        Invalid = true;
+        markInvalid("no field descriptor", P);
         continue;
       }
 
@@ -1224,16 +1228,12 @@ class ExistentialTypeInfoBuilder {
             // layering.
             auto *SuperclassTI = TC.getTypeInfo(Superclass, nullptr);
             if (SuperclassTI == nullptr) {
-              DEBUG_LOG(fprintf(stderr, "No TypeInfo for superclass: ");
-                        Superclass->dump());
-              Invalid = true;
+              markInvalid("no type info for superclass", Superclass);
               continue;
             }
 
             if (!isa<ReferenceTypeInfo>(SuperclassTI)) {
-              DEBUG_LOG(fprintf(stderr, "Superclass not a reference type: ");
-                        SuperclassTI->dump());
-              Invalid = true;
+              markInvalid("superclass not a reference type", Superclass);
               continue;
             }
 
@@ -1252,7 +1252,7 @@ class ExistentialTypeInfoBuilder {
         case FieldDescriptorKind::Enum:
         case FieldDescriptorKind::MultiPayloadEnum:
         case FieldDescriptorKind::Class:
-          Invalid = true;
+          markInvalid("unexpected field descriptor kind");
           continue;
       }
     }
@@ -1283,8 +1283,7 @@ class ExistentialTypeInfoBuilder {
       if (!isa<NominalTypeRef>(T) &&
           !isa<BoundGenericTypeRef>(T) &&
           !isa<ObjCClassTypeRef>(T)) {
-        DEBUG_LOG(fprintf(stderr, "Bad existential member: "); T->dump())
-        Invalid = true;
+        markInvalid("bad existential member", T);
         return;
       }
 
@@ -1296,8 +1295,7 @@ class ExistentialTypeInfoBuilder {
 
       const auto &FD = TC.getBuilder().getFieldDescriptor(T);
       if (FD == nullptr) {
-        DEBUG_LOG(fprintf(stderr, "No field descriptor: "); T->dump())
-        Invalid = true;
+        markInvalid("no field descriptor", T);
         return;
       }
 
@@ -1313,8 +1311,7 @@ class ExistentialTypeInfoBuilder {
         break;
 
       default:
-        DEBUG_LOG(fprintf(stderr, "Bad existential member: "); T->dump())
-        Invalid = true;
+        markInvalid("bad existential member", T);
         return;
       }
     }
@@ -1324,8 +1321,22 @@ class ExistentialTypeInfoBuilder {
     Representation = ExistentialTypeRepresentation::Class;
   }
 
-  void markInvalid() {
-    Invalid = true;
+  void addShape(const ProtocolCompositionTypeRef *Protocol,
+                ExtendedExistentialTypeShapeFlags Flags) {
+    switch (Flags.getSpecialKind()) {
+    case ExtendedExistentialTypeShapeFlags::SpecialKind::Class:
+      Representation = ExistentialTypeRepresentation::Class;
+      break;
+    case ExtendedExistentialTypeShapeFlags::SpecialKind::Metatype:
+    case ExtendedExistentialTypeShapeFlags::SpecialKind::ExplicitLayout:
+    case ExtendedExistentialTypeShapeFlags::SpecialKind::None:
+      Representation = ExistentialTypeRepresentation::Opaque;
+      break;
+    }
+
+    if (Protocol)
+      for (auto *Protocol : Protocol->getProtocols())
+        addProtocol(Protocol);
   }
 
   const TypeInfo *build(remote::TypeInfoProvider *ExternalTypeInfo) {
@@ -1407,7 +1418,7 @@ class ExistentialTypeInfoBuilder {
 
     if (ObjC) {
       if (WitnessTableCount > 0) {
-        DEBUG_LOG(fprintf(stderr, "@objc existential with witness tables\n"));
+        markInvalid("@objc existential with witness tables");
         return nullptr;
       }
 
@@ -1480,8 +1491,7 @@ void RecordTypeInfoBuilder::addField(
     remote::TypeInfoProvider *ExternalTypeInfo) {
   const TypeInfo *TI = TC.getTypeInfo(TR, ExternalTypeInfo);
   if (TI == nullptr) {
-    DEBUG_LOG(fprintf(stderr, "No TypeInfo for field type: "); TR->dump());
-    Invalid = true;
+    markInvalid("no TypeInfo for field type", TR);
     return;
   }
 
@@ -1563,6 +1573,18 @@ const ReferenceTypeInfo *TypeConverter::getReferenceTypeInfo(
   return TI;
 }
 
+std::string TypeConverter::takeLastError() {
+  if (!LastError.first)
+    return {};
+  std::stringstream s;
+  s << LastError.first << ": ";
+  if (LastError.second)
+    LastError.second->dump(s);
+
+  LastError = {nullptr, nullptr};
+  return s.str();
+}
+
 /// Thin functions consist of a function pointer. We do not use
 /// Builtin.RawPointer here, since the extra inhabitants differ.
 const TypeInfo *
@@ -1744,6 +1766,15 @@ class HasFixedSize
     return true;
   }
 
+  bool visitPackTypeRef(const PackTypeRef *P) {
+    return false;
+  }
+
+  bool visitPackExpansionTypeRef(const PackExpansionTypeRef *PE) {
+    DEBUG_LOG(fprintf(stderr, "Cannot have pack expansion type here: "); PE->dump());
+    return false;
+  }
+
   bool visitFunctionTypeRef(const FunctionTypeRef *F) {
     return true;
   }
@@ -1767,6 +1798,11 @@ class HasFixedSize
     return true;
   }
 
+  bool visitSymbolicExtendedExistentialTypeRef(
+      const SymbolicExtendedExistentialTypeRef *SEET) {
+    return true;
+  }
+
   bool
   visitSILBoxTypeRef(const SILBoxTypeRef *SB) {
     return true;
@@ -1879,6 +1915,20 @@ class HasSingletonMetatype
     return result;
   }
 
+  MetatypeRepresentation visitPackTypeRef(const PackTypeRef *P) {
+    auto result = MetatypeRepresentation::Thin;
+    for (auto Element : P->getElements())
+      result = combineRepresentations(result, visit(Element));
+    return result;
+  }
+
+  MetatypeRepresentation visitPackExpansionTypeRef(const PackExpansionTypeRef *PE) {
+    auto result = MetatypeRepresentation::Thin;
+    result = combineRepresentations(result, visit(PE->getPattern()));
+    result = combineRepresentations(result, visit(PE->getCount()));
+    return result;
+  }
+
   MetatypeRepresentation visitFunctionTypeRef(const FunctionTypeRef *F) {
     auto result = visit(F->getResult());
     for (const auto &Param : F->getParameters())
@@ -1896,6 +1946,11 @@ class HasSingletonMetatype
     return MetatypeRepresentation::Thin;
   }
 
+  MetatypeRepresentation visitSymbolicExtendedExistentialTypeRef(
+      const SymbolicExtendedExistentialTypeRef *SEET) {
+    return MetatypeRepresentation::Thin;
+  }
+
   MetatypeRepresentation visitMetatypeTypeRef(const MetatypeTypeRef *M) {
     if (M->wasAbstract())
       return MetatypeRepresentation::Thick;
@@ -1973,6 +2028,12 @@ class EnumTypeInfoBuilder {
   std::vector<FieldInfo> Cases;
   bool Invalid;
 
+  void markInvalid(const char *msg, const TypeRef *TR = nullptr) {
+    Invalid = true;
+    DEBUG_LOG(fprintf(stderr, "%s\n", msg); if (TR) TR->dump());
+    TC.setError(msg, TR);
+  }
+
   const TypeRef *getCaseTypeRef(FieldTypeInfo Case) {
     // An indirect case is like a payload case with an argument type
     // of Builtin.NativeObject.
@@ -1992,8 +2053,7 @@ class EnumTypeInfoBuilder {
   void addCase(const std::string &Name, const TypeRef *TR,
                const TypeInfo *TI) {
     if (TI == nullptr) {
-      DEBUG_LOG(fprintf(stderr, "No TypeInfo for case type: "); TR->dump());
-      Invalid = true;
+      markInvalid("no type info for case type", TR);
       static TypeInfo emptyTI;
       Cases.push_back({Name, /*offset=*/0, /*value=*/-1, TR, emptyTI});
     } else {
@@ -2022,7 +2082,7 @@ class EnumTypeInfoBuilder {
 
     std::vector<FieldTypeInfo> Fields;
     if (!TC.getBuilder().getFieldTypeRefs(TR, FD, ExternalTypeInfo, Fields)) {
-      Invalid = true;
+      markInvalid("cannot not get field types", TR);
       return nullptr;
     }
 
@@ -2037,7 +2097,7 @@ class EnumTypeInfoBuilder {
         auto *CaseTI = TC.getTypeInfo(CaseTR, ExternalTypeInfo);
         if (CaseTI == nullptr) {
           // We don't have typeinfo; something is very broken.
-          Invalid = true;
+          markInvalid("no type info for single enum case", CaseTR);
           return nullptr;
 	} else if (Case.Indirect) {
 	  // An indirect case is non-empty (it stores a pointer)
@@ -2264,8 +2324,9 @@ class LowerType
     if (auto N = dyn_cast<NominalTypeRef>(TR)) {
       Demangler Dem;
       auto Node = N->getDemangling(Dem);
-      if (Node->getKind() == Node::Kind::Type && Node->getNumChildren() == 1) {
-	auto Alias = Node->getChild(0);
+      if (Node && Node->getKind() == Node::Kind::Type &&
+          Node->getNumChildren() == 1) {
+        auto Alias = Node->getChild(0);
 	if (Alias->getKind() == Node::Kind::TypeAlias && Alias->getNumChildren() == 2) {
 	  auto Module = Alias->getChild(0);
 	  auto Name = Alias->getChild(1);
@@ -2421,6 +2482,16 @@ class LowerType
     return builder.build();
   }
 
+  const TypeInfo *visitPackTypeRef(const PackTypeRef *P) {
+    DEBUG_LOG(fprintf(stderr, "Cannot have pack type here: "); P->dump());
+    return nullptr;
+  }
+
+  const TypeInfo *visitPackExpansionTypeRef(const PackExpansionTypeRef *PE) {
+    DEBUG_LOG(fprintf(stderr, "Cannot have pack expansion type here: "); PE->dump());
+    return nullptr;
+  }
+
   const TypeInfo *visitFunctionTypeRef(const FunctionTypeRef *F) {
     switch (F->getFlags().getConvention()) {
     case FunctionMetadataConvention::Swift:
@@ -2478,6 +2549,13 @@ class LowerType
     return builder.buildMetatype(ExternalTypeInfo);
   }
 
+  const TypeInfo *visitSymbolicExtendedExistentialTypeRef(
+      const SymbolicExtendedExistentialTypeRef *SEET) {
+    ExistentialTypeInfoBuilder builder(TC);
+    builder.addShape(SEET->getProtocol(), SEET->getFlags());
+    return builder.build(ExternalTypeInfo);
+  }
+
   const TypeInfo *
   visitGenericTypeParameterTypeRef(const GenericTypeParameterTypeRef *GTP) {
     DEBUG_LOG(fprintf(stderr, "Unresolved generic TypeRef: "); GTP->dump());
@@ -2622,8 +2700,11 @@ TypeConverter::getTypeInfo(const TypeRef *TR,
       ExternalTypeInfo ? ExternalTypeInfo->getId() : 0;
   // See if we already computed the result
   auto found = Cache.find({TR, ExternalTypeInfoId});
-  if (found != Cache.end())
+  if (found != Cache.end()) {
+    if (!found->second && ErrorCache)
+      LastError = ErrorCache->lookup({TR, ExternalTypeInfoId});
     return found->second;
+  }
 
   // Detect invalid recursive value types (IRGen should not emit
   // them in the first place, but there might be bugs)
@@ -2635,6 +2716,11 @@ TypeConverter::getTypeInfo(const TypeRef *TR,
   // Compute the result and cache it
   auto *TI = LowerType(*this, ExternalTypeInfo).visit(TR);
   Cache.insert({{TR, ExternalTypeInfoId}, TI});
+  if (!TI && ErrorCache) {
+    if (!LastError.first)
+      LastError = {"cannot decode or find", TR};
+    ErrorCache->insert({{TR, ExternalTypeInfoId}, LastError});
+  }
 
   RecursionCheck.erase(TR);
 
diff --git a/stdlib/public/RemoteInspection/TypeRef.cpp b/stdlib/public/RemoteInspection/TypeRef.cpp
index bc2440bf9ee66..0c97ccb770153 100644
--- a/stdlib/public/RemoteInspection/TypeRef.cpp
+++ b/stdlib/public/RemoteInspection/TypeRef.cpp
@@ -26,6 +26,12 @@
 using namespace swift;
 using namespace reflection;
 
+#ifdef DEBUG_TYPE_LOWERING
+  #define DEBUG_LOG(expr) expr;
+#else
+  #define DEBUG_LOG(expr)
+#endif
+
 class PrintTypeRef : public TypeRefVisitor<PrintTypeRef, void> {
   std::ostream &stream;
   unsigned Indent;
@@ -122,6 +128,31 @@ class PrintTypeRef : public TypeRefVisitor<PrintTypeRef, void> {
     stream << ")";
   }
 
+  void visitPackTypeRef(const PackTypeRef *P) {
+    printHeader("pack");
+
+    for (auto Element : P->getElements()) {
+      printRec(Element);
+    }
+    stream << ")";
+  }
+
+  void visitPackExpansionTypeRef(const PackExpansionTypeRef *PE) {
+    printHeader("pack_expansion");
+
+    Indent += 2;
+    stream << "\n";
+    printHeader("pattern");
+    printRec(PE->getPattern());
+
+    stream << "\n";
+    printHeader("count");
+    printRec(PE->getCount());
+
+    stream << ")";
+    Indent -= 2;
+  }
+
   void visitFunctionTypeRef(const FunctionTypeRef *F) {
     printHeader("function");
 
@@ -258,6 +289,15 @@ class PrintTypeRef : public TypeRefVisitor<PrintTypeRef, void> {
     stream << ")";
   }
 
+  void visitSymbolicExtendedExistentialTypeRef(
+      const SymbolicExtendedExistentialTypeRef *CET) {
+    printHeader("symbolic_extended_existential_type");
+    printRec(CET->getProtocol());
+    for (auto &arg : CET->getArguments())
+      printRec(arg);
+    stream << ")";
+  }
+
   void visitMetatypeTypeRef(const MetatypeTypeRef *M) {
     printHeader("metatype");
     if (M->wasAbstract())
@@ -447,6 +487,18 @@ struct TypeRefIsConcrete
     return true;
   }
 
+  bool visitPackTypeRef(const PackTypeRef *P) {
+    for (auto Element : P->getElements()) {
+      if (!visit(Element))
+        return false;
+    }
+    return true;
+  }
+
+  bool visitPackExpansionTypeRef(const PackExpansionTypeRef *PE) {
+    return false;
+  }
+
   bool visitFunctionTypeRef(const FunctionTypeRef *F) {
     for (const auto &Param : F->getParameters())
       if (!visit(Param.getType()))
@@ -470,6 +522,15 @@ struct TypeRefIsConcrete
     return visit(CET->getBase());
   }
 
+  bool visitSymbolicExtendedExistentialTypeRef(
+      const SymbolicExtendedExistentialTypeRef *SEET) {
+    visit(SEET->getProtocol());
+    for (auto &Arg : SEET->getArguments())
+      if (!visit(Arg))
+        return false;
+    return true;
+  }
+
   bool visitMetatypeTypeRef(const MetatypeTypeRef *M) {
     return visit(M->getInstanceType());
   }
@@ -506,6 +567,13 @@ struct TypeRefIsConcrete
   }
     
   bool visitOpaqueArchetypeTypeRef(const OpaqueArchetypeTypeRef *O) {
+    for (auto Args : O->getArgumentLists()) {
+      for (auto *Arg : Args) {
+        if (!visit(Arg))
+          return false;
+      }
+    }
+
     return false;
   }
 
@@ -674,6 +742,20 @@ class DemanglingForTypeRef
     return tuple;
   }
 
+  Demangle::NodePointer visitPackTypeRef(const PackTypeRef *P) {
+    auto pack = Dem.createNode(Node::Kind::Pack);
+    for (auto Element : P->getElements())
+      pack->addChild(visit(Element), Dem);
+    return pack;
+  }
+
+  Demangle::NodePointer visitPackExpansionTypeRef(const PackExpansionTypeRef *PE) {
+    auto expansion = Dem.createNode(Node::Kind::PackExpansion);
+    expansion->addChild(visit(PE->getPattern()), Dem);
+    expansion->addChild(visit(PE->getCount()), Dem);
+    return expansion;
+  }
+
   Demangle::NodePointer visitFunctionTypeRef(const FunctionTypeRef *F) {
     Node::Kind kind;
     switch (F->getFlags().getConvention()) {
@@ -888,6 +970,19 @@ class DemanglingForTypeRef
     return node;
   }
 
+  Demangle::NodePointer visitSymbolicExtendedExistentialTypeRef(
+      const SymbolicExtendedExistentialTypeRef *SEET) {
+    auto node = Dem.createNode(Node::Kind::ConstrainedExistential);
+    node->addChild(visit(SEET->getProtocol()), Dem);
+    auto constraintList =
+        Dem.createNode(Node::Kind::ConstrainedExistentialRequirementList);
+    for (auto req : SEET->getRequirements())
+      constraintList->addChild(visitTypeRefRequirement(req), Dem);
+    node->addChild(constraintList, Dem);
+    // FIXME: This is lossy. We're dropping the Arguments here.
+    return node;
+  }
+
   Demangle::NodePointer visitMetatypeTypeRef(const MetatypeTypeRef *M) {
     auto node = Dem.createNode(Node::Kind::Metatype);
     // FIXME: This is lossy. @objc_metatype is also abstract.
@@ -1239,6 +1334,19 @@ class ThickenMetatype
     return TupleTypeRef::create(Builder, Elements, Labels);
   }
 
+  const TypeRef *visitPackTypeRef(const PackTypeRef *P) {
+    std::vector<const TypeRef *> Elements;
+    for (auto Element : P->getElements())
+      Elements.push_back(visit(Element));
+    return PackTypeRef::create(Builder, Elements);
+  }
+
+  const TypeRef *visitPackExpansionTypeRef(const PackExpansionTypeRef *PE) {
+    auto *Pattern = visit(PE->getPattern());
+    auto *Count = visit(PE->getCount());
+    return PackExpansionTypeRef::create(Builder, Pattern, Count);
+  }
+
   const TypeRef *visitFunctionTypeRef(const FunctionTypeRef *F) {
     std::vector<remote::FunctionParam<const TypeRef *>> SubstitutedParams;
     for (const auto &Param : F->getParameters()) {
@@ -1277,6 +1385,11 @@ class ThickenMetatype
                                                  CET->getRequirements());
   }
 
+  const TypeRef *visitSymbolicExtendedExistentialTypeRef(
+      const SymbolicExtendedExistentialTypeRef *SEET) {
+    return SEET;
+  }
+
   const TypeRef *visitMetatypeTypeRef(const MetatypeTypeRef *M) {
     return MetatypeTypeRef::create(Builder, visit(M->getInstanceType()),
                                    /*WasAbstract=*/true);
@@ -1350,15 +1463,49 @@ class TypeRefSubstitution
   : public TypeRefVisitor<TypeRefSubstitution, const TypeRef *> {
   TypeRefBuilder &Builder;
   GenericArgumentMap Substitutions;
-  // Set true iff the Substitution map was actually used
-  bool DidSubstitute;
+
+  std::vector<unsigned> ActivePackExpansions;
+
+  /// Simplified variant of InFlightSubstitution::expandPackExpansionShape()
+  /// that only implements the case where the replacement packs are concrete,
+  /// that is, they do not contain more pack expansions. This will always be
+  /// true here, because even more generally, our "substitution maps" do not
+  /// contain type parameters.
+  template<typename Fn>
+  bool expandPackExpansion(const PackExpansionTypeRef *origExpansion,
+                           Fn handleComponent) {
+    // Substitute the shape using the baseline substitutions, not the
+    // current elementwise projections.
+    auto *substShape = origExpansion->getCount()->subst(Builder, Substitutions);
+
+    auto *substPackShape = dyn_cast<PackTypeRef>(substShape);
+    if (!substPackShape) {
+      DEBUG_LOG(fprintf(stderr, "Replacement for pack must be another pack"));
+      return false;
+    }
+
+    ActivePackExpansions.push_back(0);
+    for (auto *substShapeElt : substPackShape->getElements()) {
+      if (isa<PackExpansionTypeRef>(substShapeElt)) {
+        DEBUG_LOG(fprintf(stderr, "Replacement pack cannot contain further expansions"));
+        return false;
+      }
+
+      auto *origPattern = origExpansion->getPattern();
+      auto *substElt = visit(origPattern);
+      handleComponent(substElt);
+
+      ++ActivePackExpansions.back();
+    }
+    ActivePackExpansions.pop_back();
+    return true;
+  }
+
 public:
   using TypeRefVisitor<TypeRefSubstitution, const TypeRef *>::visit;
 
   TypeRefSubstitution(TypeRefBuilder &Builder, GenericArgumentMap Substitutions)
-      : Builder(Builder), Substitutions(Substitutions), DidSubstitute(false) {}
-
-  bool didSubstitute() const { return DidSubstitute; }
+      : Builder(Builder), Substitutions(Substitutions) {}
 
   const TypeRef *visitBuiltinTypeRef(const BuiltinTypeRef *B) {
     return B;
@@ -1383,18 +1530,66 @@ class TypeRefSubstitution
   }
 
   const TypeRef *visitTupleTypeRef(const TupleTypeRef *T) {
+    std::vector<std::string> Labels;
     std::vector<const TypeRef *> Elements;
-    for (auto Element : T->getElements())
-      Elements.push_back(visit(Element));
-    auto Labels = T->getLabels();
+    for (auto NameElement : llvm::zip_first(T->getLabels(), T->getElements())) {
+      auto *Element = std::get<1>(NameElement);
+      if (auto *PE = dyn_cast<PackExpansionTypeRef>(Element)) {
+        bool result = expandPackExpansion(PE, [&](const TypeRef *substElt) {
+          Labels.push_back(std::get<0>(NameElement));
+          Elements.push_back(substElt);
+        });
+        if (!result)
+          return T;
+      } else {
+        Labels.push_back(std::get<0>(NameElement));
+        Elements.push_back(visit(Element));
+      }
+    }
+
+    // Unwrap one-element tuples.
+    if (Elements.size() == 1 && Labels[0].empty() &&
+        !isa<PackExpansionTypeRef>(Elements[0])) {
+      return Elements[0];
+    }
+
     return TupleTypeRef::create(Builder, Elements, Labels);
   }
 
+  const TypeRef *visitPackTypeRef(const PackTypeRef *P) {
+    std::vector<const TypeRef *> Elements;
+    for (auto Element : P->getElements()) {
+      if (auto *PE = dyn_cast<PackExpansionTypeRef>(Element)) {
+        bool result = expandPackExpansion(PE, [&](const TypeRef *substElt) {
+          Elements.push_back(substElt);
+        });
+        if (!result)
+          return P;
+      } else {
+        Elements.push_back(visit(Element));
+      }
+    }
+    return PackTypeRef::create(Builder, Elements);
+  }
+
+  const TypeRef *visitPackExpansionTypeRef(const PackExpansionTypeRef *PE) {
+    DEBUG_LOG(fprintf(stderr, "Cannot have pack expansion type here: "); PE->dump());
+    return nullptr;
+  }
+
   const TypeRef *visitFunctionTypeRef(const FunctionTypeRef *F) {
     std::vector<remote::FunctionParam<const TypeRef *>> SubstitutedParams;
     for (const auto &Param : F->getParameters()) {
-      auto typeRef = Param.getType();
-      SubstitutedParams.push_back(Param.withType(visit(typeRef)));
+      auto *TR = Param.getType();
+      if (auto *PE = dyn_cast<PackExpansionTypeRef>(TR)) {
+        bool result = expandPackExpansion(PE, [&](const TypeRef *substElt) {
+          SubstitutedParams.push_back(Param.withType(visit(substElt)));
+        });
+        if (!result)
+          return F;
+      } else {
+        SubstitutedParams.push_back(Param.withType(visit(TR)));
+      }
     }
 
     auto SubstitutedResult = visit(F->getResult());
@@ -1482,18 +1677,56 @@ class TypeRefSubstitution
                                                  constraints);
   }
 
+  const TypeRef *visitSymbolicExtendedExistentialTypeRef(
+      const SymbolicExtendedExistentialTypeRef *SEET) {
+    std::vector<TypeRefRequirement> reqs;
+    for (auto &req : SEET->getRequirements()) {
+      auto substReq = visitTypeRefRequirement(req);
+      if (!substReq)
+        continue;
+      reqs.emplace_back(*substReq);
+    }
+
+    std::vector<const TypeRef *> args;
+    for (auto *arg : SEET->getArguments()) {
+      auto *substArg = visit(arg);
+      if (!substArg)
+        return nullptr;
+      args.push_back(substArg);
+    }
+    return SymbolicExtendedExistentialTypeRef::create(
+        Builder, SEET->getProtocol(), reqs, args, SEET->getFlags());
+  }
+
   const TypeRef *
   visitGenericTypeParameterTypeRef(const GenericTypeParameterTypeRef *GTP) {
     auto found = Substitutions.find({GTP->getDepth(), GTP->getIndex()});
     if (found == Substitutions.end())
       return GTP;
-    assert(found->second->isConcrete());
-    DidSubstitute = true; // We actually used the Substitutions
+
+    auto substType = found->second;
+    assert(substType->isConcrete());
+
+    if (!ActivePackExpansions.empty()) {
+      auto *P = dyn_cast<PackTypeRef>(substType);
+      if (!P) {
+        DEBUG_LOG(fprintf(stderr, "Replacement for pack is not a pack: "); P->dump());
+        return nullptr;
+      }
+
+      unsigned index = ActivePackExpansions.back();
+      if (index >= P->getElements().size()) {
+        DEBUG_LOG(fprintf(stderr, "Packs with wrong shape: "); P->dump());
+        return nullptr;
+      }
+
+      substType = P->getElements()[index];
+    }
 
     // When substituting a concrete type containing a metatype into a
     // type parameter, (eg: T, T := C.Type), we must also represent
     // the metatype as a value.
-    return thickenMetatypes(Builder, found->second);
+    return thickenMetatypes(Builder, substType);
   }
 
   const TypeRef *visitDependentMemberTypeRef(const DependentMemberTypeRef *DM) {
@@ -1609,15 +1842,6 @@ const TypeRef *TypeRef::subst(TypeRefBuilder &Builder,
   return TypeRefSubstitution(Builder, Subs).visit(this);
 }
 
-const TypeRef *TypeRef::subst(TypeRefBuilder &Builder,
-                              const GenericArgumentMap &Subs,
-			      bool &DidSubstitute) const {
-  auto subst = TypeRefSubstitution(Builder, Subs);
-  auto TR = subst.visit(this);
-  DidSubstitute = subst.didSubstitute();
-  return TR;
-}
-
 bool TypeRef::deriveSubstitutions(GenericArgumentMap &Subs,
                                   const TypeRef *OrigTR,
                                   const TypeRef *SubstTR) {
diff --git a/stdlib/public/RemoteInspection/TypeRefBuilder.cpp b/stdlib/public/RemoteInspection/TypeRefBuilder.cpp
index d696c1056a96a..fb214d05f5025 100644
--- a/stdlib/public/RemoteInspection/TypeRefBuilder.cpp
+++ b/stdlib/public/RemoteInspection/TypeRefBuilder.cpp
@@ -39,7 +39,8 @@ TypeRefBuilder::decodeMangledType(Node *node, bool forRequirement) {
 
 std::optional<std::reference_wrapper<const ReflectionInfo>>
 TypeRefBuilder::ReflectionTypeDescriptorFinder::
-    findReflectionInfoWithTypeRefContainingAddress(uint64_t remoteAddr) {
+    findReflectionInfoWithTypeRefContainingAddress(
+        remote::RemoteAddress remoteAddr) {
   // Update ReflectionInfoIndexesSortedByTypeReferenceRange if necessary.
   if (ReflectionInfoIndexesSortedByTypeReferenceRange.size() !=
       ReflectionInfos.size()) {
@@ -54,14 +55,16 @@ TypeRefBuilder::ReflectionTypeDescriptorFinder::
         ReflectionInfoIndexesSortedByTypeReferenceRange.begin(),
         ReflectionInfoIndexesSortedByTypeReferenceRange.end(),
         [&](uint32_t ReflectionInfoIndexA, uint32_t ReflectionInfoIndexB) {
-          uint64_t typeReferenceAStart = ReflectionInfos[ReflectionInfoIndexA]
-                                             .TypeReference.startAddress()
-                                             .getAddressData();
-          uint64_t typeReferenceBStart = ReflectionInfos[ReflectionInfoIndexB]
-                                             .TypeReference.startAddress()
-                                             .getAddressData();
-
-          return typeReferenceAStart < typeReferenceBStart;
+          remote::RemoteAddress typeReferenceAStart =
+              ReflectionInfos[ReflectionInfoIndexA]
+                  .TypeReference.startAddress()
+                  .getRemoteAddress();
+          remote::RemoteAddress typeReferenceBStart =
+              ReflectionInfos[ReflectionInfoIndexB]
+                  .TypeReference.startAddress()
+                  .getRemoteAddress();
+
+          return typeReferenceAStart.orderedLessThan(typeReferenceBStart);
         });
   }
 
@@ -71,10 +74,12 @@ TypeRefBuilder::ReflectionTypeDescriptorFinder::
   const auto possiblyMatchingReflectionInfoIndex = std::lower_bound(
       ReflectionInfoIndexesSortedByTypeReferenceRange.begin(),
       ReflectionInfoIndexesSortedByTypeReferenceRange.end(), remoteAddr,
-      [&](uint32_t ReflectionInfoIndex, uint64_t remoteAddr) {
-        return ReflectionInfos[ReflectionInfoIndex]
-                   .TypeReference.endAddress()
-                   .getAddressData() <= remoteAddr;
+      [&](uint32_t ReflectionInfoIndex, remote::RemoteAddress remoteAddr) {
+        auto reflectionInfoAddress = ReflectionInfos[ReflectionInfoIndex]
+                                         .TypeReference.endAddress()
+                                         .getRemoteAddress();
+
+        return reflectionInfoAddress.orderedLessThanOrEqual(remoteAddr);
       });
 
   if (possiblyMatchingReflectionInfoIndex ==
@@ -97,7 +102,7 @@ TypeRefBuilder::ReflectionTypeDescriptorFinder::
 }
 
 RemoteRef<char> TypeRefBuilder::ReflectionTypeDescriptorFinder::readTypeRef(
-    uint64_t remoteAddr) {
+    remote::RemoteAddress remoteAddr) {
   // The remote address should point into one of the TypeRef or
   // ReflectionString references we already read out of the images.
   RemoteRef<char> foundTypeRef;
@@ -129,7 +134,7 @@ RemoteRef<char> TypeRefBuilder::ReflectionTypeDescriptorFinder::readTypeRef(
   // Make sure there's a valid mangled string within the bounds of the
   // section.
   for (auto i = foundTypeRef;
-       i.getAddressData() < limitAddress.getAddressData();) {
+       i.getRemoteAddress() < limitAddress.getRemoteAddress();) {
     auto c = *i.getLocalBuffer();
     if (c == '\0')
       goto valid_type_ref;
@@ -160,7 +165,7 @@ RemoteRef<char> TypeRefBuilder::ReflectionTypeDescriptorFinder::readTypeRef(
 std::optional<std::string>
 TypeRefBuilder::ReflectionTypeDescriptorFinder::normalizeReflectionName(
     RemoteRef<char> reflectionName) {
-  const auto reflectionNameRemoteAddress = reflectionName.getAddressData();
+  const auto reflectionNameRemoteAddress = reflectionName.getRemoteAddress();
 
   if (const auto found =
           NormalizedReflectionNameCache.find(reflectionNameRemoteAddress);
@@ -353,13 +358,13 @@ TypeRefBuilder::ReflectionTypeDescriptorFinder::
       return std::nullopt;
 
     auto &Field = ReflectionInfos[Locator->InfoID].Field;
-    auto Addr = Field.startAddress().getAddressData() + Locator->Offset;
+    auto Addr = Field.startAddress().getRemoteAddress() + Locator->Offset;
 
     // Validate that we've got the correct field descriptor offset by parsing
     // the mangled name for that specific offset and making sure it's the one
     // we're looking for.
     for (auto FD : Field) {
-      if (FD.getAddressData() == Addr) {
+      if (FD.getRemoteAddress() == Addr) {
         if (!FD->hasMangledTypeName())
           break;
         auto CandidateMangledName = readTypeRef(FD, FD->MangledTypeName);
@@ -538,8 +543,9 @@ bool TypeRefBuilder::getFieldTypeRefs(
     // We need this for enums; an enum case "is generic" if any generic type
     // parameter substitutions occurred on the payload.  E.g.,
     // `case a([T?])` is generic, but `case a([Int?])` is not.
-    bool IsGeneric = false;
-    auto Substituted = Unsubstituted->subst(*this, *Subs, IsGeneric);
+    bool IsGeneric = !Unsubstituted->isConcrete();
+    auto Substituted = (IsGeneric ? Unsubstituted->subst(*this, *Subs)
+                                  : Unsubstituted);
     bool IsIndirect = FD.isEnum() && Field->IsIndirectCase;
 
     auto FieldTI = FieldTypeInfo(FieldName.str(), FieldValue, Substituted,
@@ -748,7 +754,7 @@ TypeRefBuilder::getMultiPayloadEnumDescriptor(const TypeRef *TR) {
 
 RemoteRef<CaptureDescriptor>
 TypeRefBuilder::ReflectionTypeDescriptorFinder::getCaptureDescriptor(
-    uint64_t RemoteAddress) {
+    remote::RemoteAddress RemoteAddress) {
 
   for (; CaptureDescriptorsByAddressLastReflectionInfoCache <
          ReflectionInfos.size();
@@ -757,7 +763,7 @@ TypeRefBuilder::ReflectionTypeDescriptorFinder::getCaptureDescriptor(
          ReflectionInfos[CaptureDescriptorsByAddressLastReflectionInfoCache]
              .Capture) {
       CaptureDescriptorsByAddress.emplace(
-          std::make_pair(CD.getAddressData(), CD));
+          std::make_pair(CD.getRemoteAddress(), CD));
     }
   }
 
diff --git a/stdlib/public/RuntimeModule/Elf.swift b/stdlib/public/RuntimeModule/Elf.swift
index 006a62c456b79..96d57264eae22 100644
--- a/stdlib/public/RuntimeModule/Elf.swift
+++ b/stdlib/public/RuntimeModule/Elf.swift
@@ -1064,8 +1064,8 @@ struct ElfSymbolTable<SomeElfTraits: ElfTraits>: ElfSymbolTableProtocol {
           continue
         }
 
-        // Ignore anything undefined
-        if symbol.st_shndx == SHN_UNDEF {
+        // Ignore anything undefined or absolute
+        if symbol.st_shndx == SHN_UNDEF || symbol.st_shndx == SHN_ABS {
           continue
         }
 
@@ -1190,6 +1190,8 @@ final class ElfImage<SomeElfTraits: ElfTraits>
   var sectionHeaders: [Traits.Shdr]?
   var shouldByteSwap: Bool { return header.shouldByteSwap }
 
+  var imageBase: ImageSource.Address
+
   @_specialize(kind: full, where SomeElfTraits == Elf32Traits)
   @_specialize(kind: full, where SomeElfTraits == Elf64Traits)
   required init(source: ImageSource,
@@ -1222,11 +1224,21 @@ final class ElfImage<SomeElfTraits: ElfTraits>
 
     var phdrs: [Traits.Phdr] = []
     var phAddr = ImageSource.Address(header.e_phoff)
+    var minAddr: Traits.Address? = nil
     for _ in 0..<header.e_phnum {
       let phdr = maybeSwap(try source.fetch(from: phAddr, as: Traits.Phdr.self))
       phdrs.append(phdr)
       phAddr += ImageSource.Address(header.e_phentsize)
+
+      if phdr.p_type == .PT_LOAD {
+        if let oldMinAddr = minAddr {
+          minAddr = min(oldMinAddr, phdr.p_vaddr)
+        } else {
+          minAddr = phdr.p_vaddr
+        }
+      }
     }
+    imageBase = ImageSource.Address(exactly: minAddr ?? 0)!
     programHeaders = phdrs
 
     if source.isMappedImage {
@@ -1463,6 +1475,11 @@ final class ElfImage<SomeElfTraits: ElfTraits>
       let stringSect = ElfStringSection(source: stringSource)
 
       for shdr in sectionHeaders {
+        // All other fields are undefined for SHT_NULL
+        if shdr.sh_type == .SHT_NULL {
+          continue
+        }
+
         guard let name = stringSect.getStringAt(index: Int(shdr.sh_name)) else {
           continue
         }
@@ -1600,6 +1617,11 @@ final class ElfImage<SomeElfTraits: ElfTraits>
         let stringSect = ElfStringSection(source: stringSource)
 
         for shdr in sectionHeaders {
+          // All other fields are undefined for SHT_NULL
+          if shdr.sh_type == .SHT_NULL {
+            continue
+          }
+
           guard let sname
                   = stringSect.getStringAt(index: Int(shdr.sh_name)) else {
             continue
diff --git a/stdlib/public/RuntimeModule/SymbolicatedBacktrace.swift b/stdlib/public/RuntimeModule/SymbolicatedBacktrace.swift
index 214231cdc284f..19ce102a6dd56 100644
--- a/stdlib/public/RuntimeModule/SymbolicatedBacktrace.swift
+++ b/stdlib/public/RuntimeModule/SymbolicatedBacktrace.swift
@@ -466,9 +466,6 @@ public struct SymbolicatedBacktrace: CustomStringConvertible {
     for frame in backtrace.frames {
       let address = frame.adjustedProgramCounter
       if let imageNdx = theImages.indexOfImage(at: address) {
-        let relativeAddress = ImageSource.Address(
-          address - theImages[imageNdx].baseAddress
-        )
         let name = theImages[imageNdx].name ?? "<unknown>"
         var symbol: Symbol = Symbol(imageIndex: imageNdx,
                                     imageName: name,
@@ -527,6 +524,9 @@ public struct SymbolicatedBacktrace: CustomStringConvertible {
         if let hit = cache.lookup(path: theImages[imageNdx].path) {
           switch hit {
             case let .elf32Image(image):
+              let relativeAddress = ImageSource.Address(
+                address - theImages[imageNdx].baseAddress
+              ) + image.imageBase
               if let theSymbol = lookupSymbol(image: image,
                                               at: imageNdx,
                                               named: name,
@@ -534,6 +534,9 @@ public struct SymbolicatedBacktrace: CustomStringConvertible {
                 symbol = theSymbol
               }
             case let .elf64Image(image):
+              let relativeAddress = ImageSource.Address(
+                address - theImages[imageNdx].baseAddress
+              ) + image.imageBase
               if let theSymbol = lookupSymbol(image: image,
                                               at: imageNdx,
                                               named: name,
diff --git a/stdlib/public/SwiftOnoneSupport/CMakeLists.txt b/stdlib/public/SwiftOnoneSupport/CMakeLists.txt
index a7a105938b15b..3e55a7ed2dd7a 100644
--- a/stdlib/public/SwiftOnoneSupport/CMakeLists.txt
+++ b/stdlib/public/SwiftOnoneSupport/CMakeLists.txt
@@ -7,7 +7,7 @@ set(swiftOnoneSupport_common_options
 
   "${SWIFT_SOURCE_DIR}/stdlib/linker-support/magic-symbols-for-install-name.c"
 
-  SWIFT_COMPILE_FLAGS "-parse-stdlib" "-Xllvm" "-sil-inline-generics=false" "-Xfrontend" "-validate-tbd-against-ir=none" "-Xfrontend" "-check-onone-completeness" "-Xfrontend" "-disable-access-control" "-strict-memory-safety" "${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS}" "${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}"
+  SWIFT_COMPILE_FLAGS "-parse-stdlib" "-Xllvm" "-sil-inline-generics=false" "-Xfrontend" "-validate-tbd-against-ir=none" "-Xfrontend" "-check-onone-completeness" "-Xfrontend" "-disable-access-control" "-strict-memory-safety" "-enable-experimental-feature" "AllowUnsafeAttribute" "${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS}" "${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}"
   LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}")
 
 if(CMAKE_BUILD_TYPE STREQUAL "Debug" AND BOOTSTRAPPING_MODE STREQUAL "BOOTSTRAPPING")
diff --git a/stdlib/public/SwiftOnoneSupport/SwiftOnoneSupport.swift b/stdlib/public/SwiftOnoneSupport/SwiftOnoneSupport.swift
index 841e65b9876ea..b67fa2675ad27 100644
--- a/stdlib/public/SwiftOnoneSupport/SwiftOnoneSupport.swift
+++ b/stdlib/public/SwiftOnoneSupport/SwiftOnoneSupport.swift
@@ -19,6 +19,9 @@ import Swift
 // actual generic function name. The "prespecialize" annotation forces
 // the actual generic function to be specialized based on the argument
 // types passed to the proxy function.
+//
+// The list of symbols generated by prespecialization can be found at the path
+// "lib/SILOptimizer/Utils/OnonePrespecializations.def"
 // =============================================================================
 
 extension Collection {
diff --git a/stdlib/public/SwiftRemoteMirror/SwiftRemoteMirror.cpp b/stdlib/public/SwiftRemoteMirror/SwiftRemoteMirror.cpp
index d17a2860358bb..6f76a5c14c86a 100644
--- a/stdlib/public/SwiftRemoteMirror/SwiftRemoteMirror.cpp
+++ b/stdlib/public/SwiftRemoteMirror/SwiftRemoteMirror.cpp
@@ -101,8 +101,8 @@ struct SwiftReflectionContext {
   }
 
   // Call fn with a pointer to context.
-  template <typename T, typename Fn>
-  T withContext(const Fn &fn) {
+  template <typename Fn>
+  auto withContext(const Fn &fn) {
     return std::visit([&](auto &&context) { return fn(context.get()); },
                       this->context);
   }
@@ -233,7 +233,9 @@ ReflectionSection<Iterator> sectionFromInfo(const swift_reflection_info_t &Info,
     - Info.LocalStartAddress
     + Info.RemoteStartAddress;
 
-  auto Start = RemoteRef<void>(RemoteSectionStart, Section.section.Begin);
+  auto Start = RemoteRef<void>(
+      RemoteAddress(RemoteSectionStart, RemoteAddress::DefaultAddressSpace),
+      Section.section.Begin);
 
   return ReflectionSection<Iterator>(Start,
              (uintptr_t)Section.section.End - (uintptr_t)Section.section.Begin);
@@ -244,7 +246,9 @@ ReflectionSection<Iterator> reflectionSectionFromLocalAndRemote(
     const swift_reflection_section_mapping_t &Section) {
   auto RemoteSectionStart = (uint64_t)Section.remote_section.StartAddress;
 
-  auto Start = RemoteRef<void>(RemoteSectionStart, Section.local_section.Begin);
+  auto Start = RemoteRef<void>(
+      RemoteAddress(RemoteSectionStart, RemoteAddress::DefaultAddressSpace),
+      Section.local_section.Begin);
 
   return ReflectionSection<Iterator>(Start,
                                      (uintptr_t)Section.remote_section.Size);
@@ -253,7 +257,7 @@ ReflectionSection<Iterator> reflectionSectionFromLocalAndRemote(
 void
 swift_reflection_addReflectionInfo(SwiftReflectionContextRef ContextRef,
                                    swift_reflection_info_t Info) {
-  ContextRef->withContext<void>([&](auto *Context) {
+  ContextRef->withContext([&](auto *Context) {
     // The `offset` fields must be zero.
     if (Info.field.offset != 0
         || Info.associated_types.offset != 0
@@ -284,7 +288,7 @@ swift_reflection_addReflectionInfo(SwiftReflectionContextRef ContextRef,
 void swift_reflection_addReflectionMappingInfo(
     SwiftReflectionContextRef ContextRef,
     swift_reflection_mapping_info_t Info) {
-  return ContextRef->withContext<void>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     ReflectionInfo ContextInfo{
         reflectionSectionFromLocalAndRemote<FieldDescriptorIterator>(
             Info.field),
@@ -308,15 +312,18 @@ void swift_reflection_addReflectionMappingInfo(
 int
 swift_reflection_addImage(SwiftReflectionContextRef ContextRef,
                           swift_addr_t imageStart) {
-  return ContextRef->withContext<int>([&](auto *Context) {
-    return Context->addImage(RemoteAddress(imageStart)).has_value();
+  return ContextRef->withContext([&](auto *Context) {
+    return Context
+        ->addImage(
+            RemoteAddress(imageStart, RemoteAddress::DefaultAddressSpace))
+        .has_value();
   });
 }
 
 int
 swift_reflection_readIsaMask(SwiftReflectionContextRef ContextRef,
                              uintptr_t *outIsaMask) {
-  return ContextRef->withContext<int>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto isaMask = Context->readIsaMask();
     if (isaMask) {
       *outIsaMask = *isaMask;
@@ -330,76 +337,85 @@ swift_reflection_readIsaMask(SwiftReflectionContextRef ContextRef,
 swift_typeref_t
 swift_reflection_typeRefForMetadata(SwiftReflectionContextRef ContextRef,
                                     uintptr_t Metadata) {
-  return ContextRef->withContext<swift_typeref_t>([&](auto *Context) {
-    auto TR = Context->readTypeFromMetadata(Metadata);
+  return ContextRef->withContext([&](auto *Context) {
+    auto TR = Context->readTypeFromMetadata(
+        RemoteAddress(Metadata, RemoteAddress::DefaultAddressSpace));
     return reinterpret_cast<swift_typeref_t>(TR);
   });
 }
 
 int
 swift_reflection_ownsObject(SwiftReflectionContextRef ContextRef, uintptr_t Object) {
-  return ContextRef->withContext<int>([&](auto *Context) {
-    return Context->ownsObject(RemoteAddress(Object));
+  return ContextRef->withContext([&](auto *Context) {
+    return Context->ownsObject(
+        RemoteAddress(Object, RemoteAddress::DefaultAddressSpace));
   });
 }
 
 int
 swift_reflection_ownsAddress(SwiftReflectionContextRef ContextRef, uintptr_t Address) {
-  return ContextRef->withContext<int>([&](auto *Context) {
-    return Context->ownsAddress(RemoteAddress(Address));
+  return ContextRef->withContext([&](auto *Context) {
+    return Context->ownsAddress(
+        RemoteAddress(Address, RemoteAddress::DefaultAddressSpace));
   });
 }
 
 int
 swift_reflection_ownsAddressStrict(SwiftReflectionContextRef ContextRef, uintptr_t Address) {
-  return ContextRef->withContext<int>([&](auto *Context) {
-    return Context->ownsAddress(RemoteAddress(Address), false);
+  return ContextRef->withContext([&](auto *Context) {
+    return Context->ownsAddress(
+        RemoteAddress(Address, RemoteAddress::DefaultAddressSpace), false);
   });
 }
 
 uintptr_t
 swift_reflection_metadataForObject(SwiftReflectionContextRef ContextRef,
                                    uintptr_t Object) {
-  return ContextRef->withContext<uintptr_t>([&](auto *Context) -> uintptr_t {
-    auto MetadataAddress = Context->readMetadataFromInstance(Object);
+  return ContextRef->withContext([&](auto *Context) -> uintptr_t {
+    auto MetadataAddress = Context->readMetadataFromInstance(
+        RemoteAddress(Object, RemoteAddress::DefaultAddressSpace));
     if (!MetadataAddress)
       return 0;
-    return *MetadataAddress;
+    return MetadataAddress->getRawAddress();
   });
 }
 
 swift_reflection_ptr_t
 swift_reflection_metadataNominalTypeDescriptor(SwiftReflectionContextRef ContextRef,
                                                swift_reflection_ptr_t MetadataAddress) {
-  return ContextRef->withContext<swift_reflection_ptr_t>([&](auto *Context) {
-    return Context->nominalTypeDescriptorFromMetadata(MetadataAddress);
+  return ContextRef->withContext([&](auto *Context) {
+    auto Address = Context->nominalTypeDescriptorFromMetadata(
+        RemoteAddress(MetadataAddress, RemoteAddress::DefaultAddressSpace));
+    return Address.getRawAddress();
   });
 }
 
 int swift_reflection_metadataIsActor(SwiftReflectionContextRef ContextRef,
                                      swift_reflection_ptr_t Metadata) {
-  return ContextRef->withContext<int>(
-      [&](auto *Context) { return Context->metadataIsActor(Metadata); });
+  return ContextRef->withContext([&](auto *Context) {
+    return Context->metadataIsActor(
+        RemoteAddress(Metadata, RemoteAddress::DefaultAddressSpace));
+  });
 }
 
 swift_typeref_t
 swift_reflection_typeRefForInstance(SwiftReflectionContextRef ContextRef,
                                     uintptr_t Object) {
-  return ContextRef->withContext<swift_typeref_t>(
-      [&](auto *Context) -> swift_typeref_t {
-        auto MetadataAddress = Context->readMetadataFromInstance(Object);
-        if (!MetadataAddress)
-          return 0;
-        auto TR = Context->readTypeFromMetadata(*MetadataAddress);
-        return reinterpret_cast<swift_typeref_t>(TR);
-      });
+  return ContextRef->withContext([&](auto *Context) -> swift_typeref_t {
+    auto MetadataAddress = Context->readMetadataFromInstance(
+        RemoteAddress(Object, RemoteAddress::DefaultAddressSpace));
+    if (!MetadataAddress)
+      return 0;
+    auto TR = Context->readTypeFromMetadata(*MetadataAddress);
+    return reinterpret_cast<swift_typeref_t>(TR);
+  });
 }
 
 swift_typeref_t
 swift_reflection_typeRefForMangledTypeName(SwiftReflectionContextRef ContextRef,
                                            const char *MangledTypeName,
                                            uint64_t Length) {
-  return ContextRef->withContext<swift_typeref_t>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto TR =
         Context->readTypeFromMangledName(MangledTypeName, Length).getType();
     return reinterpret_cast<swift_typeref_t>(TR);
@@ -426,12 +442,19 @@ swift_reflection_copyNameForTypeRef(SwiftReflectionContextRef ContextRef,
   if (mangled) {
     auto Mangling = mangleNode(TR->getDemangling(Dem), Mangle::ManglingFlavor::Default);
     if (Mangling.isSuccess()) {
+#if defined(_WIN32)
+      return _strdup(Mangling.result().c_str());
+#else
       return strdup(Mangling.result().c_str());
+#endif
     }
-  }
-  else {
+  } else {
     auto Name = nodeToString(TR->getDemangling(Dem));
+#if defined(_WIN32)
+    return _strdup(Name.c_str());
+#else
     return strdup(Name.c_str());
+#endif
   }
   return nullptr;
 }
@@ -440,12 +463,17 @@ SWIFT_REMOTE_MIRROR_LINKAGE
 char *
 swift_reflection_copyDemangledNameForProtocolDescriptor(
   SwiftReflectionContextRef ContextRef, swift_reflection_ptr_t Proto) {
-  return ContextRef->withContext<char *>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
 
     Demangle::Demangler Dem;
-    auto Demangling = Context->readDemanglingForContextDescriptor(Proto, Dem);
+    auto Demangling = Context->readDemanglingForContextDescriptor(
+        RemoteAddress(Proto, RemoteAddress::DefaultAddressSpace), Dem);
     auto Name = nodeToString(Demangling);
+#if defined(_WIN32)
+    return _strdup(Name.c_str());
+#else
     return strdup(Name.c_str());
+#endif
   });
 }
 
@@ -627,7 +655,7 @@ static const char *returnableCString(SwiftReflectionContextRef ContextRef,
 swift_typeinfo_t
 swift_reflection_infoForTypeRef(SwiftReflectionContextRef ContextRef,
                                 swift_typeref_t OpaqueTypeRef) {
-  return ContextRef->withContext<swift_typeinfo_t>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto TR = reinterpret_cast<const TypeRef *>(OpaqueTypeRef);
     auto TI = Context->getTypeInfo(TR, nullptr);
     return convertTypeInfo(TI);
@@ -638,7 +666,7 @@ swift_childinfo_t
 swift_reflection_childOfTypeRef(SwiftReflectionContextRef ContextRef,
                                 swift_typeref_t OpaqueTypeRef,
                                 unsigned Index) {
-  return ContextRef->withContext<swift_childinfo_t>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto TR = reinterpret_cast<const TypeRef *>(OpaqueTypeRef);
     auto *TI = Context->getTypeInfo(TR, nullptr);
     return convertChild(TI, Index);
@@ -648,8 +676,9 @@ swift_reflection_childOfTypeRef(SwiftReflectionContextRef ContextRef,
 swift_typeinfo_t
 swift_reflection_infoForMetadata(SwiftReflectionContextRef ContextRef,
                                  uintptr_t Metadata) {
-  return ContextRef->withContext<swift_typeinfo_t>([&](auto *Context) {
-    auto *TI = Context->getMetadataTypeInfo(Metadata, nullptr);
+  return ContextRef->withContext([&](auto *Context) {
+    auto *TI = Context->getMetadataTypeInfo(
+        RemoteAddress(Metadata, RemoteAddress::DefaultAddressSpace), nullptr);
     return convertTypeInfo(TI);
   });
 }
@@ -658,8 +687,9 @@ swift_childinfo_t
 swift_reflection_childOfMetadata(SwiftReflectionContextRef ContextRef,
                                  uintptr_t Metadata,
                                  unsigned Index) {
-  return ContextRef->withContext<swift_childinfo_t>([&](auto *Context) {
-    auto *TI = Context->getMetadataTypeInfo(Metadata, nullptr);
+  return ContextRef->withContext([&](auto *Context) {
+    auto *TI = Context->getMetadataTypeInfo(
+        RemoteAddress(Metadata, RemoteAddress::DefaultAddressSpace), nullptr);
     return convertChild(TI, Index);
   });
 }
@@ -667,8 +697,9 @@ swift_reflection_childOfMetadata(SwiftReflectionContextRef ContextRef,
 swift_typeinfo_t
 swift_reflection_infoForInstance(SwiftReflectionContextRef ContextRef,
                                  uintptr_t Object) {
-  return ContextRef->withContext<swift_typeinfo_t>([&](auto *Context) {
-    auto *TI = Context->getInstanceTypeInfo(Object, nullptr);
+  return ContextRef->withContext([&](auto *Context) {
+    auto *TI = Context->getInstanceTypeInfo(
+        RemoteAddress(Object, RemoteAddress::DefaultAddressSpace), nullptr);
     return convertTypeInfo(TI);
   });
 }
@@ -677,8 +708,9 @@ swift_childinfo_t
 swift_reflection_childOfInstance(SwiftReflectionContextRef ContextRef,
                                  uintptr_t Object,
                                  unsigned Index) {
-  return ContextRef->withContext<swift_childinfo_t>([&](auto *Context) {
-    auto *TI = Context->getInstanceTypeInfo(Object, nullptr);
+  return ContextRef->withContext([&](auto *Context) {
+    auto *TI = Context->getInstanceTypeInfo(
+        RemoteAddress(Object, RemoteAddress::DefaultAddressSpace), nullptr);
     return convertChild(TI, Index);
   });
 }
@@ -688,18 +720,19 @@ int swift_reflection_projectExistential(SwiftReflectionContextRef ContextRef,
                                         swift_typeref_t ExistentialTypeRef,
                                         swift_typeref_t *InstanceTypeRef,
                                         swift_addr_t *StartOfInstanceData) {
-  return ContextRef->withContext<int>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto ExistentialTR = reinterpret_cast<const TypeRef *>(ExistentialTypeRef);
-    auto RemoteExistentialAddress = RemoteAddress(ExistentialAddress);
+    auto RemoteExistentialAddress =
+        RemoteAddress(ExistentialAddress, RemoteAddress::DefaultAddressSpace);
     const TypeRef *InstanceTR = nullptr;
-    RemoteAddress RemoteStartOfInstanceData(nullptr);
+    RemoteAddress RemoteStartOfInstanceData;
     auto Success = Context->projectExistential(
         RemoteExistentialAddress, ExistentialTR, &InstanceTR,
         &RemoteStartOfInstanceData, nullptr);
 
     if (Success) {
       *InstanceTypeRef = reinterpret_cast<swift_typeref_t>(InstanceTR);
-      *StartOfInstanceData = RemoteStartOfInstanceData.getAddressData();
+      *StartOfInstanceData = RemoteStartOfInstanceData.getRawAddress();
     }
 
     return Success;
@@ -711,16 +744,17 @@ int swift_reflection_projectExistentialAndUnwrapClass(SwiftReflectionContextRef
                                         swift_typeref_t ExistentialTypeRef,
                                         swift_typeref_t *InstanceTypeRef,
                                         swift_addr_t *StartOfInstanceData) {
-  return ContextRef->withContext<int>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto ExistentialTR = reinterpret_cast<const TypeRef *>(ExistentialTypeRef);
-    auto RemoteExistentialAddress = RemoteAddress(ExistentialAddress);
+    auto RemoteExistentialAddress =
+        RemoteAddress(ExistentialAddress, RemoteAddress::DefaultAddressSpace);
     auto Pair = Context->projectExistentialAndUnwrapClass(
         RemoteExistentialAddress, *ExistentialTR);
     if (!Pair.has_value())
       return false;
     *InstanceTypeRef =
         reinterpret_cast<swift_typeref_t>(std::get<const TypeRef *>(*Pair));
-    *StartOfInstanceData = std::get<RemoteAddress>(*Pair).getAddressData();
+    *StartOfInstanceData = std::get<RemoteAddress>(*Pair).getRawAddress();
 
     return true;
   });
@@ -730,9 +764,10 @@ int swift_reflection_projectEnumValue(SwiftReflectionContextRef ContextRef,
                                       swift_addr_t EnumAddress,
                                       swift_typeref_t EnumTypeRef,
                                       int *CaseIndex) {
-  return ContextRef->withContext<int>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto EnumTR = reinterpret_cast<const TypeRef *>(EnumTypeRef);
-    auto RemoteEnumAddress = RemoteAddress(EnumAddress);
+    auto RemoteEnumAddress =
+        RemoteAddress(EnumAddress, RemoteAddress::DefaultAddressSpace);
     if (!Context->projectEnumValue(RemoteEnumAddress, EnumTR, CaseIndex,
                                    nullptr)) {
       return false;
@@ -758,7 +793,7 @@ void swift_reflection_dumpTypeRef(swift_typeref_t OpaqueTypeRef) {
 
 void swift_reflection_dumpInfoForTypeRef(SwiftReflectionContextRef ContextRef,
                                          swift_typeref_t OpaqueTypeRef) {
-  ContextRef->withContext<void>([&](auto *Context) {
+  ContextRef->withContext([&](auto *Context) {
     auto TR = reinterpret_cast<const TypeRef *>(OpaqueTypeRef);
     auto TI = Context->getTypeInfo(TR, nullptr);
     if (TI == nullptr) {
@@ -790,8 +825,9 @@ void swift_reflection_dumpInfoForTypeRef(SwiftReflectionContextRef ContextRef,
 
 void swift_reflection_dumpInfoForMetadata(SwiftReflectionContextRef ContextRef,
                                           uintptr_t Metadata) {
-  ContextRef->withContext<void>([&](auto *Context) {
-    auto TI = Context->getMetadataTypeInfo(Metadata, nullptr);
+  ContextRef->withContext([&](auto *Context) {
+    auto TI = Context->getMetadataTypeInfo(
+        RemoteAddress(Metadata, RemoteAddress::DefaultAddressSpace), nullptr);
     if (TI == nullptr) {
       std::cout << "<null type info>\n";
     } else {
@@ -802,8 +838,9 @@ void swift_reflection_dumpInfoForMetadata(SwiftReflectionContextRef ContextRef,
 
 void swift_reflection_dumpInfoForInstance(SwiftReflectionContextRef ContextRef,
                                           uintptr_t Object) {
-  ContextRef->withContext<void>([&](auto *Context) {
-    auto TI = Context->getInstanceTypeInfo(Object, nullptr);
+  ContextRef->withContext([&](auto *Context) {
+    auto TI = Context->getInstanceTypeInfo(
+        RemoteAddress(Object, RemoteAddress::DefaultAddressSpace), nullptr);
     if (TI == nullptr) {
       std::cout << "<null type info>\n";
     } else {
@@ -819,7 +856,13 @@ size_t swift_reflection_demangle(const char *MangledName, size_t Length,
 
   std::string Mangled(MangledName, Length);
   auto Demangled = Demangle::demangleTypeAsString(Mangled);
+#if defined(_WIN32)
+  errno_t err = strncpy_s(OutDemangledName, MaxLength,
+                          Demangled.c_str(), _TRUNCATE);
+  static_cast<void>(err);
+#else
   strncpy(OutDemangledName, Demangled.c_str(), MaxLength);
+#endif
   return Demangled.size();
 }
 
@@ -829,9 +872,9 @@ const char *swift_reflection_iterateConformanceCache(
                swift_reflection_ptr_t Proto,
                void *ContextPtr),
   void *ContextPtr) {
-  return ContextRef->withContext<const char *>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto Error = Context->iterateConformances([&](auto Type, auto Proto) {
-      Call(Type, Proto, ContextPtr);
+      Call(Type.getRawAddress(), Proto.getRawAddress(), ContextPtr);
     });
     return returnableCString(ContextRef, Error);
   });
@@ -842,7 +885,7 @@ const char *swift_reflection_iterateMetadataAllocations(
   void (*Call)(swift_metadata_allocation_t Allocation,
                void *ContextPtr),
   void *ContextPtr) {
-  return ContextRef->withContext<const char *>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto Error = Context->iterateMetadataAllocations([&](auto Allocation) {
       swift_metadata_allocation CAllocation;
       CAllocation.Tag = Allocation.Tag;
@@ -877,7 +920,7 @@ static MetadataAllocation<Runtime> convertMetadataAllocation(
 swift_reflection_ptr_t swift_reflection_allocationMetadataPointer(
   SwiftReflectionContextRef ContextRef,
   swift_metadata_allocation_t Allocation) {
-  return ContextRef->withContext<swift_reflection_ptr_t>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto ConvertedAllocation = convertMetadataAllocation(Context, Allocation);
     return Context->allocationMetadataPointer(ConvertedAllocation);
   });
@@ -885,7 +928,7 @@ swift_reflection_ptr_t swift_reflection_allocationMetadataPointer(
 
 const char *swift_reflection_metadataAllocationTagName(
     SwiftReflectionContextRef ContextRef, swift_metadata_allocation_tag_t Tag) {
-  return ContextRef->withContext<const char *>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto Result = Context->metadataAllocationTagName(Tag);
     return returnableCString(ContextRef, Result);
   });
@@ -895,7 +938,7 @@ int swift_reflection_metadataAllocationCacheNode(
     SwiftReflectionContextRef ContextRef,
     swift_metadata_allocation_t Allocation,
     swift_metadata_cache_node_t *OutNode) {
-  return ContextRef->withContext<int>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto ConvertedAllocation = convertMetadataAllocation(Context, Allocation);
 
     auto Result = Context->metadataAllocationCacheNode(ConvertedAllocation);
@@ -911,7 +954,7 @@ int swift_reflection_metadataAllocationCacheNode(
 const char *swift_reflection_iterateMetadataAllocationBacktraces(
     SwiftReflectionContextRef ContextRef,
     swift_metadataAllocationBacktraceIterator Call, void *ContextPtr) {
-  return ContextRef->withContext<const char *>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     auto Error = Context->iterateMetadataAllocationBacktraces(
         [&](auto AllocationPtr, auto Count, auto Ptrs) {
           // Ptrs is an array of StoredPointer, but the callback expects an
@@ -931,75 +974,75 @@ const char *swift_reflection_iterateMetadataAllocationBacktraces(
 swift_async_task_slab_return_t
 swift_reflection_asyncTaskSlabPointer(SwiftReflectionContextRef ContextRef,
                                       swift_reflection_ptr_t AsyncTaskPtr) {
-  return ContextRef->withContext<swift_async_task_slab_return_t>(
-      [&](auto *Context) {
-        // We only care about the AllocatorSlabPtr field. Disable child task and
-        // async backtrace iteration to save wasted work.
-        unsigned ChildTaskLimit = 0;
-        unsigned AsyncBacktraceLimit = 0;
-
-        auto [Error, TaskInfo] = Context->asyncTaskInfo(
-            AsyncTaskPtr, ChildTaskLimit, AsyncBacktraceLimit);
-
-        swift_async_task_slab_return_t Result = {};
-        if (Error) {
-          Result.Error = returnableCString(ContextRef, Error);
-        }
-        Result.SlabPtr = TaskInfo.AllocatorSlabPtr;
-        return Result;
-      });
+  return ContextRef->withContext([&](auto *Context) {
+    // We only care about the AllocatorSlabPtr field. Disable child task and
+    // async backtrace iteration to save wasted work.
+    unsigned ChildTaskLimit = 0;
+    unsigned AsyncBacktraceLimit = 0;
+
+    auto [Error, TaskInfo] = Context->asyncTaskInfo(
+        RemoteAddress(AsyncTaskPtr, RemoteAddress::DefaultAddressSpace),
+        ChildTaskLimit, AsyncBacktraceLimit);
+
+    swift_async_task_slab_return_t Result = {};
+    if (Error) {
+      Result.Error = returnableCString(ContextRef, Error);
+    }
+    Result.SlabPtr = TaskInfo.AllocatorSlabPtr;
+    return Result;
+  });
 }
 
 swift_async_task_slab_allocations_return_t
 swift_reflection_asyncTaskSlabAllocations(SwiftReflectionContextRef ContextRef,
                                           swift_reflection_ptr_t SlabPtr) {
-  return ContextRef->withContext<swift_async_task_slab_allocations_return_t>(
-      [&](auto *Context) {
-        auto [Error, Info] = Context->asyncTaskSlabAllocations(SlabPtr);
-
-        swift_async_task_slab_allocations_return_t Result = {};
-        if (Result.Error) {
-          Result.Error = returnableCString(ContextRef, Error);
-          return Result;
-        }
-
-        Result.NextSlab = Info.NextSlab;
-        Result.SlabSize = Info.SlabSize;
-
-        auto *Chunks = ContextRef->allocateTemporaryObject<
-            std::vector<swift_async_task_allocation_chunk_t>>();
-        Chunks->reserve(Info.Chunks.size());
-        for (auto &Chunk : Info.Chunks) {
-          swift_async_task_allocation_chunk_t ConvertedChunk;
-          ConvertedChunk.Start = Chunk.Start;
-          ConvertedChunk.Length = Chunk.Length;
-
-          // This pedantry is required to properly template over *Context.
-          ConvertedChunk.Kind = convertAllocationChunkKind<
-              typename std::pointer_traits<decltype(Context)>::element_type>(
-              Chunk.Kind);
-
-          Chunks->push_back(ConvertedChunk);
-        }
-
-        Result.ChunkCount = Chunks->size();
-        Result.Chunks = Chunks->data();
-
-        return Result;
-      });
+  return ContextRef->withContext([&](auto *Context) {
+    auto [Error, Info] = Context->asyncTaskSlabAllocations(SlabPtr);
+
+    swift_async_task_slab_allocations_return_t Result = {};
+    if (Result.Error) {
+      Result.Error = returnableCString(ContextRef, Error);
+      return Result;
+    }
+
+    Result.NextSlab = Info.NextSlab;
+    Result.SlabSize = Info.SlabSize;
+
+    auto *Chunks = ContextRef->allocateTemporaryObject<
+        std::vector<swift_async_task_allocation_chunk_t>>();
+    Chunks->reserve(Info.Chunks.size());
+    for (auto &Chunk : Info.Chunks) {
+      swift_async_task_allocation_chunk_t ConvertedChunk;
+      ConvertedChunk.Start = Chunk.Start;
+      ConvertedChunk.Length = Chunk.Length;
+
+      // This pedantry is required to properly template over *Context.
+      ConvertedChunk.Kind = convertAllocationChunkKind<
+          typename std::pointer_traits<decltype(Context)>::element_type>(
+          Chunk.Kind);
+
+      Chunks->push_back(ConvertedChunk);
+    }
+
+    Result.ChunkCount = Chunks->size();
+    Result.Chunks = Chunks->data();
+
+    return Result;
+  });
 }
 
 swift_async_task_info_t
 swift_reflection_asyncTaskInfo(SwiftReflectionContextRef ContextRef,
                                swift_reflection_ptr_t AsyncTaskPtr) {
-  return ContextRef->withContext<swift_async_task_info_t>([&](auto *Context) {
+  return ContextRef->withContext([&](auto *Context) {
     // Limit the child task and async backtrace iteration to semi-reasonable
     // numbers to avoid doing excessive work on bad data.
     unsigned ChildTaskLimit = 1000000;
     unsigned AsyncBacktraceLimit = 1000;
 
     auto [Error, TaskInfo] = Context->asyncTaskInfo(
-        AsyncTaskPtr, ChildTaskLimit, AsyncBacktraceLimit);
+        RemoteAddress(AsyncTaskPtr, RemoteAddress::DefaultAddressSpace),
+        ChildTaskLimit, AsyncBacktraceLimit);
 
     swift_async_task_info_t Result = {};
     if (Error) {
@@ -1053,8 +1096,9 @@ swift_reflection_asyncTaskInfo(SwiftReflectionContextRef ContextRef,
 swift_actor_info_t
 swift_reflection_actorInfo(SwiftReflectionContextRef ContextRef,
                            swift_reflection_ptr_t ActorPtr) {
-  return ContextRef->withContext<swift_actor_info_t>([&](auto *Context) {
-    auto [Error, ActorInfo] = Context->actorInfo(ActorPtr);
+  return ContextRef->withContext([&](auto *Context) {
+    auto [Error, ActorInfo] = Context->actorInfo(
+        RemoteAddress(ActorPtr, RemoteAddress::DefaultAddressSpace));
 
     swift_actor_info_t Result = {};
     Result.Error = returnableCString(ContextRef, Error);
@@ -1074,7 +1118,8 @@ swift_reflection_actorInfo(SwiftReflectionContextRef ContextRef,
 swift_reflection_ptr_t
 swift_reflection_nextJob(SwiftReflectionContextRef ContextRef,
                          swift_reflection_ptr_t JobPtr) {
-  return ContextRef->withContext<swift_reflection_ptr_t>([&](auto *Context) {
-    return Context->nextJob(JobPtr);
+  return ContextRef->withContext([&](auto *Context) {
+    return Context->nextJob(
+        RemoteAddress(JobPtr, RemoteAddress::DefaultAddressSpace));
   });
 }
diff --git a/stdlib/public/SwiftShims/swift/shims/CMakeLists.txt b/stdlib/public/SwiftShims/swift/shims/CMakeLists.txt
index 19565ed4ad945..d664cddcd614a 100644
--- a/stdlib/public/SwiftShims/swift/shims/CMakeLists.txt
+++ b/stdlib/public/SwiftShims/swift/shims/CMakeLists.txt
@@ -155,6 +155,10 @@ add_custom_command_target(unused_var
 
 add_dependencies(copy_shim_headers symlink_clang_headers_static)
 
+# Add dependency to ensure that the static headers are installed. This is needed because no target
+# depends on the static headers, so they would not be installed otherwise.
+add_dependencies(symlink_clang_headers symlink_clang_headers_static)
+
 if(NOT SWIFT_BUILT_STANDALONE)
   if(TARGET clang-resource-headers) # LLVM > 8
     set(clang_resource_headers clang-resource-headers)
diff --git a/stdlib/public/SwiftShims/swift/shims/CoreFoundationShims.h b/stdlib/public/SwiftShims/swift/shims/CoreFoundationShims.h
index 60dbba9a28bc0..ffba3ee5cf507 100644
--- a/stdlib/public/SwiftShims/swift/shims/CoreFoundationShims.h
+++ b/stdlib/public/SwiftShims/swift/shims/CoreFoundationShims.h
@@ -35,6 +35,8 @@ typedef unsigned long _swift_shims_CFHashCode;
 typedef signed long _swift_shims_CFIndex;
 #endif
 
+typedef unsigned long _swift_shims_NSUInteger;
+
 // Consider creating SwiftMacTypes.h for these
 typedef unsigned char _swift_shims_Boolean;
 typedef __swift_uint8_t _swift_shims_UInt8;
@@ -80,6 +82,11 @@ const void * _Nullable
 _swift_stdlib_CreateIndirectTaggedPointerString(const __swift_uint8_t * _Nonnull bytes,
                                                 _swift_shims_CFIndex len);
 
+SWIFT_RUNTIME_STDLIB_API
+_swift_shims_NSUInteger
+_swift_stdlib_NSStringLengthOfBytesInEncodingTrampoline(id _Nonnull obj,
+                                                        unsigned long encoding);
+
 #endif // __OBJC2__
 
 #ifdef __cplusplus
diff --git a/stdlib/public/SwiftShims/swift/shims/LibcOverlayShims.h b/stdlib/public/SwiftShims/swift/shims/LibcOverlayShims.h
index 25ac7c701b551..f4ef162bd09ca 100644
--- a/stdlib/public/SwiftShims/swift/shims/LibcOverlayShims.h
+++ b/stdlib/public/SwiftShims/swift/shims/LibcOverlayShims.h
@@ -121,15 +121,15 @@ int static inline _swift_stdlib_openat(int fd, const char *path, int oflag,
 #endif
 
 #if defined(__OpenBSD__)
-static inline FILE *_swift_stdlib_stdin(void) {
+static inline void *_swift_stdlib_stdin(void) {
   return stdin;
 }
 
-static inline FILE *_swift_stdlib_stdout(void) {
+static inline void *_swift_stdlib_stdout(void) {
   return stdout;
 }
 
-static inline FILE *_swift_stdlib_stderr(void) {
+static inline void *_swift_stdlib_stderr(void) {
   return stderr;
 }
 #endif
diff --git a/stdlib/public/SwiftShims/swift/shims/SwiftStdint.h b/stdlib/public/SwiftShims/swift/shims/SwiftStdint.h
index 386186df0962c..b73807cc6f86a 100644
--- a/stdlib/public/SwiftShims/swift/shims/SwiftStdint.h
+++ b/stdlib/public/SwiftShims/swift/shims/SwiftStdint.h
@@ -24,7 +24,7 @@
 
 // Clang has been defining __INTxx_TYPE__ macros for a long time.
 // __UINTxx_TYPE__ are defined only since Clang 3.5.
-#if !defined(__APPLE__) && !defined(__linux__) && !defined(__OpenBSD__) && !defined(__wasi__)
+#if !defined(__APPLE__) && !defined(__linux__) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__wasi__) && !defined(__swift_embedded__)
 #include <stdint.h>
 typedef int64_t __swift_int64_t;
 typedef uint64_t __swift_uint64_t;
diff --git a/stdlib/public/SwiftShims/swift/shims/System.h b/stdlib/public/SwiftShims/swift/shims/System.h
index 53afedf3eff97..328f81ebece67 100644
--- a/stdlib/public/SwiftShims/swift/shims/System.h
+++ b/stdlib/public/SwiftShims/swift/shims/System.h
@@ -220,8 +220,8 @@
 
 // WebAssembly doesn't reserve low addresses. But without "extra inhabitants" of
 // the pointer representation, runtime performance and memory footprint are
-// worse. So assume that compiler driver uses wasm-ld and --global-base=1024 to
-// reserve low 1KB.
+// worse. So assume that compiler driver uses wasm-ld and --global-base=4096 to
+// reserve low 4KB.
 #define SWIFT_ABI_WASM32_LEAST_VALID_POINTER 4096
 
 #endif // SWIFT_STDLIB_SHIMS_ABI_SYSTEM_H
diff --git a/stdlib/public/SwiftShims/swift/shims/_SynchronizationShims.h b/stdlib/public/SwiftShims/swift/shims/_SynchronizationShims.h
index 70a1eb6e004f0..0386a570df00f 100644
--- a/stdlib/public/SwiftShims/swift/shims/_SynchronizationShims.h
+++ b/stdlib/public/SwiftShims/swift/shims/_SynchronizationShims.h
@@ -66,4 +66,9 @@ static inline __swift_uint32_t _swift_stdlib_futex_unlock(__swift_uint32_t *lock
 
 #endif // defined(__linux__)
 
+#if defined(__FreeBSD__)
+#include <sys/types.h>
+#include <sys/umtx.h>
+#endif
+
 #endif // SWIFT_STDLIB_SYNCHRONIZATION_SHIMS_H
diff --git a/stdlib/public/Synchronization/Atomics/Atomic.swift b/stdlib/public/Synchronization/Atomics/Atomic.swift
index da599199b6cee..bcc1f4ced5936 100644
--- a/stdlib/public/Synchronization/Atomics/Atomic.swift
+++ b/stdlib/public/Synchronization/Atomics/Atomic.swift
@@ -29,7 +29,7 @@ public struct Atomic<Value: AtomicRepresentable>: ~Copyable {
   @_alwaysEmitIntoClient
   @_transparent
   var _rawAddress: Builtin.RawPointer {
-    Builtin.unprotectedAddressOfBorrow(self)
+    Builtin.addressOfRawLayout(self)
   }
 
   /// Initializes a value of this atomic with the given initial value.
diff --git a/stdlib/public/Synchronization/Atomics/AtomicBool.swift b/stdlib/public/Synchronization/Atomics/AtomicBool.swift
index 34f30469d136b..b9417a0ea119c 100644
--- a/stdlib/public/Synchronization/Atomics/AtomicBool.swift
+++ b/stdlib/public/Synchronization/Atomics/AtomicBool.swift
@@ -77,7 +77,7 @@ extension Atomic where Value == Bool {
   ///
   /// - Parameter operand: A boolean value.
   /// - Parameter ordering: The memory ordering to apply on this operation.
-  /// - Returns: A tuple with the old value before the operation a the new value
+  /// - Returns: A tuple with the old value before the operation and the new value
   ///   after the operation.
   @available(SwiftStdlib 6.0, *)
   @discardableResult
@@ -135,7 +135,7 @@ extension Atomic where Value == Bool {
   ///
   /// - Parameter operand: A boolean value.
   /// - Parameter ordering: The memory ordering to apply on this operation.
-  /// - Returns: A tuple with the old value before the operation a the new value
+  /// - Returns: A tuple with the old value before the operation and the new value
   ///   after the operation.
   @available(SwiftStdlib 6.0, *)
   @discardableResult
@@ -193,7 +193,7 @@ extension Atomic where Value == Bool {
   ///
   /// - Parameter operand: A boolean value.
   /// - Parameter ordering: The memory ordering to apply on this operation.
-  /// - Returns: A tuple with the old value before the operation a the new value
+  /// - Returns: A tuple with the old value before the operation and the new value
   ///   after the operation.
   @available(SwiftStdlib 6.0, *)
   @discardableResult
diff --git a/stdlib/public/Synchronization/Atomics/AtomicIntegers.swift.gyb b/stdlib/public/Synchronization/Atomics/AtomicIntegers.swift.gyb
index 32ea1b7f0212d..e5888cdcb919b 100644
--- a/stdlib/public/Synchronization/Atomics/AtomicIntegers.swift.gyb
+++ b/stdlib/public/Synchronization/Atomics/AtomicIntegers.swift.gyb
@@ -163,6 +163,11 @@ extension Atomic where Value == ${intType} {
   ///   overflow does occur. In `-Ounchecked` builds, overflow checking is not
   ///   performed.
   ///
+  ///   The need to check for overflow means that this operation is typically
+  ///   compiled into a compare-exchange loop. For use cases that require a
+  ///   direct atomic addition, see the `wrappingAdd` operation: it avoids the
+  ///   loop, but in exchange it allows silent wraps on overflow.
+  ///
   /// - Parameter operand: An integer value.
   /// - Parameter ordering: The memory ordering to apply on this operation.
   /// - Returns: A tuple containing the original value before the operation and
@@ -202,6 +207,11 @@ extension Atomic where Value == ${intType} {
   ///   overflow does occur. In `-Ounchecked` builds, overflow checking is not
   ///   performed.
   ///
+  ///   The need to check for overflow means that this operation is typically
+  ///   compiled into a compare-exchange loop. For use cases that require a
+  ///   direct atomic subtraction, see the `wrappingSubtract` operation: it
+  ///   avoids the loop, but in exchange it allows silent wraps on overflow.
+  ///
   /// - Parameter operand: An integer value.
   /// - Parameter ordering: The memory ordering to apply on this operation.
   /// - Returns: A tuple containing the original value before the operation and
diff --git a/stdlib/public/Synchronization/Atomics/AtomicPointers.swift b/stdlib/public/Synchronization/Atomics/AtomicPointers.swift
index 2c5e4b06e9ac2..286c1ba9afa95 100644
--- a/stdlib/public/Synchronization/Atomics/AtomicPointers.swift
+++ b/stdlib/public/Synchronization/Atomics/AtomicPointers.swift
@@ -822,7 +822,7 @@ extension UnsafeBufferPointer: @unsafe AtomicRepresentable where Element: ~Copya
   public static func decodeAtomicRepresentation(
     _ representation: consuming AtomicRepresentation
   ) -> UnsafeBufferPointer<Element> {
-    let wp = unsafe WordPair.decodeAtomicRepresentation(representation)
+    let wp = WordPair.decodeAtomicRepresentation(representation)
 
     return unsafe UnsafeBufferPointer<Element>(
       start: UnsafePointer<Element>(bitPattern: wp.first),
@@ -890,7 +890,7 @@ where Element: ~Copyable
   public static func decodeAtomicRepresentation(
     _ representation: consuming AtomicRepresentation
   ) -> UnsafeMutableBufferPointer<Element> {
-    let wp = unsafe WordPair.decodeAtomicRepresentation(representation)
+    let wp = WordPair.decodeAtomicRepresentation(representation)
 
     return unsafe UnsafeMutableBufferPointer<Element>(
       start: UnsafeMutablePointer<Element>(bitPattern: wp.first),
@@ -956,7 +956,7 @@ extension UnsafeRawBufferPointer: @unsafe AtomicRepresentable {
   public static func decodeAtomicRepresentation(
     _ representation: consuming AtomicRepresentation
   ) -> UnsafeRawBufferPointer {
-    let wp = unsafe WordPair.decodeAtomicRepresentation(representation)
+    let wp = WordPair.decodeAtomicRepresentation(representation)
 
     return unsafe UnsafeRawBufferPointer(
       start: UnsafeRawPointer(bitPattern: wp.first),
@@ -1022,7 +1022,7 @@ extension UnsafeMutableRawBufferPointer: @unsafe AtomicRepresentable {
   public static func decodeAtomicRepresentation(
     _ representation: consuming AtomicRepresentation
   ) -> UnsafeMutableRawBufferPointer {
-    let wp = unsafe WordPair.decodeAtomicRepresentation(representation)
+    let wp = WordPair.decodeAtomicRepresentation(representation)
 
     return unsafe UnsafeMutableRawBufferPointer(
       start: UnsafeMutableRawPointer(bitPattern: wp.first),
diff --git a/stdlib/public/Synchronization/Atomics/AtomicRepresentable.swift b/stdlib/public/Synchronization/Atomics/AtomicRepresentable.swift
index 7cf1e5790ed77..206d3508846bd 100644
--- a/stdlib/public/Synchronization/Atomics/AtomicRepresentable.swift
+++ b/stdlib/public/Synchronization/Atomics/AtomicRepresentable.swift
@@ -47,7 +47,7 @@
 /// conformance synthesis for enums by declaring our "raw value" to be a
 /// `UInt8`. By adding the `AtomicRepresentable` conformance, we automatically
 /// figure out how to do the conformance from the `RawRepresentable`
-/// implementation and do all of th necessary work for you. However, it is still
+/// implementation and do all of the necessary work for you. However, it is still
 /// possible to customize this behavior using the manual method explained below.
 ///
 /// Defining your own `AtomicRepresentable` conformance is pretty simple. All
diff --git a/stdlib/public/Synchronization/CMakeLists.txt b/stdlib/public/Synchronization/CMakeLists.txt
index d924943cee70f..7eeb1b4bc2ad3 100644
--- a/stdlib/public/Synchronization/CMakeLists.txt
+++ b/stdlib/public/Synchronization/CMakeLists.txt
@@ -37,8 +37,13 @@ set(SWIFT_SYNCHRONIZATION_GYB_SOURCES
 
 set(SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES)
 
-if(SWIFT_BUILD_SDK_OVERLAY)
-  set(SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES Darwin)
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  # This library imports Darwin from the SDK, which re-exports
+  # _Builtin_float which is part of this build.
+  list(APPEND SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES _Builtin_float)
 endif()
 
 set(SWIFT_SYNCHRONIZATION_DARWIN_SOURCES
@@ -54,6 +59,13 @@ set(SWIFT_SYNCHRONIZATION_LINUX_SOURCES
   Mutex/SpinLoopHint.swift
 )
 
+# FreeBSD sources
+
+set(SWIFT_SYNCHRONIZATION_FREEBSD_SOURCES
+  Mutex/FreeBSDImpl.swift
+  Mutex/Mutex.swift
+)
+
 # Wasm sources
 
 set(SWIFT_SYNCHRONIZATION_WASM_SOURCES
@@ -68,6 +80,13 @@ set(SWIFT_SYNCHRONIZATION_WINDOWS_SOURCES
   Mutex/WindowsImpl.swift
 )
 
+# OpenBSD sources
+
+set(SWIFT_SYNCHRONIZATION_OPENBSD_SOURCES
+  Mutex/Mutex.swift
+  Mutex/OpenBSDImpl.swift
+)
+
 set(SWIFT_SYNCHRNOIZATION_SWIFT_FLAGS
   ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   "-enable-builtin-module"
@@ -77,7 +96,7 @@ set(SWIFT_SYNCHRNOIZATION_SWIFT_FLAGS
   "-strict-memory-safety"
 )
 
-add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB IMPORTS_NON_OSSA 
+add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   ${SWIFT_SYNCHRONIZATION_SOURCES}
 
   GYB_SOURCES
@@ -101,6 +120,10 @@ add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES
     ${SWIFT_SYNCHRONIZATION_WASM_SOURCES}
   SWIFT_SOURCES_DEPENDS_WINDOWS
     ${SWIFT_SYNCHRONIZATION_WINDOWS_SOURCES}
+  SWIFT_SOURCES_DEPENDS_FREEBSD
+    ${SWIFT_SYNCHRONIZATION_FREEBSD_SOURCES}
+  SWIFT_SOURCES_DEPENDS_OPENBSD
+    ${SWIFT_SYNCHRONIZATION_OPENBSD_SOURCES}
   SWIFT_SOURCES_DEPENDS_FREESTANDING
     Mutex/MutexUnavailable.swift
 
@@ -124,6 +147,10 @@ add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES
     Android
   SWIFT_MODULE_DEPENDS_WINDOWS
     WinSDK
+  SWIFT_MODULE_DEPENDS_FREEBSD
+    Glibc
+  SWIFT_MODULE_DEPENDS_OPENBSD
+    Glibc
 
   SWIFT_COMPILE_FLAGS
     ${SWIFT_SYNCHRNOIZATION_SWIFT_FLAGS}
@@ -142,6 +169,12 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
   add_custom_target(embedded-synchronization)
   add_dependencies(embedded-libraries embedded-synchronization)
 
+  set(SWIFT_ENABLE_REFLECTION OFF)
+  set(SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT OFF)
+  set(SWIFT_STDLIB_STABLE_ABI OFF)
+  set(SWIFT_STDLIB_ENABLE_OBJC_INTEROP OFF)
+  set(SWIFT_STDLIB_ENABLE_VECTOR_TYPES OFF)
+
   foreach(entry ${EMBEDDED_STDLIB_TARGET_TRIPLES})
     string(REGEX REPLACE "[ \t]+" ";" list "${entry}")
     list(GET list 0 arch)
@@ -152,13 +185,10 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
     if("${arch}" MATCHES "avr")
       continue()
     endif()
-    
+
     set(SWIFT_SDK_embedded_ARCH_${arch}_MODULE "${mod}")
     set(SWIFT_SDK_embedded_LIB_SUBDIR "embedded")
     set(SWIFT_SDK_embedded_ARCH_${arch}_TRIPLE "${triple}")
-    set(SWIFT_SDK_embedded_PATH ${SWIFT_SDK_OSX_PATH})
-    set(SWIFT_SDK_embedded_ARCH_${arch}_PATH ${SWIFT_SDK_OSX_PATH})
-    set(SWIFT_SDK_embedded_USE_ISYSROOT TRUE)
     add_swift_target_library_single(
       embedded-synchronization-${mod}
       swiftSynchronization
diff --git a/stdlib/public/Synchronization/Cell.swift b/stdlib/public/Synchronization/Cell.swift
index 75dde59cdcf85..c169ac7b5fa43 100644
--- a/stdlib/public/Synchronization/Cell.swift
+++ b/stdlib/public/Synchronization/Cell.swift
@@ -14,13 +14,12 @@ import Builtin
 
 @available(SwiftStdlib 6.0, *)
 @frozen
-@usableFromInline
 @_rawLayout(like: Value, movesAsLike)
-internal struct _Cell<Value: ~Copyable>: ~Copyable {
+public struct _Cell<Value: ~Copyable>: ~Copyable {
   @available(SwiftStdlib 6.0, *)
   @_alwaysEmitIntoClient
   @_transparent
-  internal var _address: UnsafeMutablePointer<Value> {
+  public var _address: UnsafeMutablePointer<Value> {
     unsafe UnsafeMutablePointer<Value>(_rawAddress)
   }
 
@@ -34,7 +33,7 @@ internal struct _Cell<Value: ~Copyable>: ~Copyable {
   @available(SwiftStdlib 6.0, *)
   @_alwaysEmitIntoClient
   @_transparent
-  internal init(_ initialValue: consuming Value) {
+  public init(_ initialValue: consuming Value) {
     unsafe _address.initialize(to: initialValue)
   }
 
diff --git a/stdlib/public/Synchronization/Mutex/FreeBSDImpl.swift b/stdlib/public/Synchronization/Mutex/FreeBSDImpl.swift
new file mode 100644
index 0000000000000..666e574278fda
--- /dev/null
+++ b/stdlib/public/Synchronization/Mutex/FreeBSDImpl.swift
@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Atomics open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import Glibc
+
+@available(SwiftStdlib 6.0, *)
+@frozen
+@_staticExclusiveOnly
+public struct _MutexHandle: ~Copyable {
+  @usableFromInline
+  let value: _Cell<umutex>
+
+  @available(SwiftStdlib 6.0, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  public init() {
+    value = _Cell(umutex())
+  }
+
+  @available(SwiftStdlib 6.0, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal borrowing func _lock() {
+    _umtx_op(value._address, UMTX_OP_MUTEX_LOCK, 0, nil, nil)
+  }
+
+  @available(SwiftStdlib 6.0, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal borrowing func _tryLock() -> Bool {
+    _umtx_op(value._address, UMTX_OP_MUTEX_TRYLOCK, 0, nil, nil) != -1
+  }
+
+  @available(SwiftStdlib 6.0, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal borrowing func _unlock() {
+    _umtx_op(value._address, UMTX_OP_MUTEX_UNLOCK, 0, nil, nil)
+  }
+}
diff --git a/stdlib/public/Synchronization/Mutex/LinuxImpl.swift b/stdlib/public/Synchronization/Mutex/LinuxImpl.swift
index a45a6fe5168da..d2d5f74edc3c9 100644
--- a/stdlib/public/Synchronization/Mutex/LinuxImpl.swift
+++ b/stdlib/public/Synchronization/Mutex/LinuxImpl.swift
@@ -23,19 +23,19 @@ extension Atomic where Value == UInt32 {
   // This returns 'false' on success and 'true' on error. Check 'errno' for the
   // specific error value.
   internal borrowing func _futexLock() -> UInt32 {
-    _swift_stdlib_futex_lock(.init(_rawAddress))
+    unsafe _swift_stdlib_futex_lock(.init(_rawAddress))
   }
 
   // This returns 'false' on success and 'true' on error. Check 'errno' for the
   // specific error value.
   internal borrowing func _futexTryLock() -> UInt32 {
-    _swift_stdlib_futex_trylock(.init(_rawAddress))
+    unsafe _swift_stdlib_futex_trylock(.init(_rawAddress))
   }
 
   // This returns 'false' on success and 'true' on error. Check 'errno' for the
   // specific error value.
   internal borrowing func _futexUnlock() -> UInt32 {
-    _swift_stdlib_futex_unlock(.init(_rawAddress))
+    unsafe _swift_stdlib_futex_unlock(.init(_rawAddress))
   }
 }
 
diff --git a/stdlib/public/Synchronization/Mutex/OpenBSDImpl.swift b/stdlib/public/Synchronization/Mutex/OpenBSDImpl.swift
new file mode 100644
index 0000000000000..ad4de24cf28b6
--- /dev/null
+++ b/stdlib/public/Synchronization/Mutex/OpenBSDImpl.swift
@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Atomics open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import Glibc
+
+@available(SwiftStdlib 6.0, *)
+@frozen
+@_staticExclusiveOnly
+public struct _MutexHandle: ~Copyable {
+  @usableFromInline
+  let value: _Cell<pthread_mutex_t?>
+
+  @available(SwiftStdlib 6.0, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  public init() {
+    var mx = pthread_mutex_t(bitPattern: 0)
+    pthread_mutex_init(&mx, nil)
+    value = _Cell(mx)
+  }
+
+  @available(SwiftStdlib 6.0, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal borrowing func _lock() {
+    pthread_mutex_lock(value._address)
+  }
+
+  @available(SwiftStdlib 6.0, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal borrowing func _tryLock() -> Bool {
+    pthread_mutex_trylock(value._address) != 0
+  }
+
+  @available(SwiftStdlib 6.0, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal borrowing func _unlock() {
+    pthread_mutex_unlock(value._address)
+  }
+
+  @available(SwiftStdlib 6.0, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  deinit {
+    pthread_mutex_destroy(value._address)
+  }
+}
diff --git a/stdlib/public/Synchronization/Mutex/WasmImpl.swift b/stdlib/public/Synchronization/Mutex/WasmImpl.swift
index 6c58628c40eeb..2e6560a601e7c 100644
--- a/stdlib/public/Synchronization/Mutex/WasmImpl.swift
+++ b/stdlib/public/Synchronization/Mutex/WasmImpl.swift
@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Note: All atomic accesses on WASM are sequentially consistent regardless of
+// Note: All atomic accesses on Wasm are sequentially consistent regardless of
 // what ordering we tell LLVM to use.
 
 @_extern(c, "llvm.wasm.memory.atomic.wait32")
@@ -26,7 +26,7 @@ internal func _swift_stdlib_wake(on: UnsafePointer<UInt32>, count: UInt32) -> UI
 extension Atomic where Value == _MutexHandle.State {
   internal borrowing func _wait(expected: _MutexHandle.State) {
     #if _runtime(_multithreaded)
-    _ = _swift_stdlib_wait(
+    _ = unsafe _swift_stdlib_wait(
       on: .init(_rawAddress),
       expected: expected.rawValue,
 
@@ -39,7 +39,7 @@ extension Atomic where Value == _MutexHandle.State {
   internal borrowing func _wake() {
     #if _runtime(_multithreaded)
     // Only wake up 1 thread
-    _ = _swift_stdlib_wake(on: .init(_rawAddress), count: 1)
+    _ = unsafe _swift_stdlib_wake(on: .init(_rawAddress), count: 1)
     #endif
   }
 }
diff --git a/stdlib/public/Synchronization/Mutex/WindowsImpl.swift b/stdlib/public/Synchronization/Mutex/WindowsImpl.swift
index e97072b35c7a7..ba7eeb63047ae 100644
--- a/stdlib/public/Synchronization/Mutex/WindowsImpl.swift
+++ b/stdlib/public/Synchronization/Mutex/WindowsImpl.swift
@@ -14,6 +14,7 @@ import WinSDK.core.synch
 
 @available(SwiftStdlib 6.0, *)
 @frozen
+@safe
 @_staticExclusiveOnly
 public struct _MutexHandle: ~Copyable {
   @usableFromInline
@@ -23,14 +24,14 @@ public struct _MutexHandle: ~Copyable {
   @_alwaysEmitIntoClient
   @_transparent
   public init() {
-    value = _Cell(SRWLOCK())
+    unsafe value = _Cell(SRWLOCK())
   }
 
   @available(SwiftStdlib 6.0, *)
   @_alwaysEmitIntoClient
   @_transparent
   internal borrowing func _lock() {
-    AcquireSRWLockExclusive(value._address)
+    unsafe AcquireSRWLockExclusive(value._address)
   }
 
   @available(SwiftStdlib 6.0, *)
@@ -38,13 +39,13 @@ public struct _MutexHandle: ~Copyable {
   @_transparent
   internal borrowing func _tryLock() -> Bool {
     // Windows BOOLEAN gets imported as 'UInt8'...
-    TryAcquireSRWLockExclusive(value._address) != 0
+    unsafe TryAcquireSRWLockExclusive(value._address) != 0
   }
 
   @available(SwiftStdlib 6.0, *)
   @_alwaysEmitIntoClient
   @_transparent
   internal borrowing func _unlock() {
-    ReleaseSRWLockExclusive(value._address)
+    unsafe ReleaseSRWLockExclusive(value._address)
   }
 }
diff --git a/stdlib/public/Volatile/CMakeLists.txt b/stdlib/public/Volatile/CMakeLists.txt
index bf08132740c2d..dd91f0fa88f52 100644
--- a/stdlib/public/Volatile/CMakeLists.txt
+++ b/stdlib/public/Volatile/CMakeLists.txt
@@ -40,7 +40,7 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
       IS_SDK_OVERLAY IS_FRAGILE
 
       Volatile.swift
-      
+
       SWIFT_COMPILE_FLAGS
         -Xcc -ffreestanding -enable-experimental-feature Embedded
         -parse-stdlib
diff --git a/stdlib/public/Windows/WinSDK.swift b/stdlib/public/Windows/WinSDK.swift
index 57b162390eeaa..cfa0f2fdee6b5 100644
--- a/stdlib/public/Windows/WinSDK.swift
+++ b/stdlib/public/Windows/WinSDK.swift
@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 @_exported import ucrt
+@_exported import _GUIDDef
 @_exported import WinSDK // Clang module
 
 // WinBase.h
@@ -56,7 +57,7 @@ public var STD_ERROR_HANDLE: DWORD {
 // handleapi.h
 @inlinable
 public var INVALID_HANDLE_VALUE: HANDLE {
-  HANDLE(bitPattern: -1)!
+  unsafe HANDLE(bitPattern: -1)!
 }
 
 // shellapi.h
@@ -163,78 +164,78 @@ public var PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE: DWORD_PTR {
 // windef.h
 @inlinable
 public var DPI_AWARENESS_CONTEXT_UNAWARE: DPI_AWARENESS_CONTEXT {
-  DPI_AWARENESS_CONTEXT(bitPattern: -1)!
+  unsafe DPI_AWARENESS_CONTEXT(bitPattern: -1)!
 }
 
 @inlinable
 public var DPI_AWARENESS_CONTEXT_SYSTEM_AWARE: DPI_AWARENESS_CONTEXT {
-  DPI_AWARENESS_CONTEXT(bitPattern: -2)!
+  unsafe DPI_AWARENESS_CONTEXT(bitPattern: -2)!
 }
 
 @inlinable
 public var DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE: DPI_AWARENESS_CONTEXT {
-  DPI_AWARENESS_CONTEXT(bitPattern: -3)!
+  unsafe DPI_AWARENESS_CONTEXT(bitPattern: -3)!
 }
 
 @inlinable
 public var DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2: DPI_AWARENESS_CONTEXT {
-  DPI_AWARENESS_CONTEXT(bitPattern: -4)!
+  unsafe DPI_AWARENESS_CONTEXT(bitPattern: -4)!
 }
 
 @inlinable
 public var DPI_AWARENESS_CONTEXT_UNAWARE_GDISCALED: DPI_AWARENESS_CONTEXT {
-  DPI_AWARENESS_CONTEXT(bitPattern: -5)!
+  unsafe DPI_AWARENESS_CONTEXT(bitPattern: -5)!
 }
 
 // winreg.h
 @inlinable
 public var HKEY_CLASSES_ROOT: HKEY {
-  HKEY(bitPattern: UInt(0x80000000))!
+  unsafe HKEY(bitPattern: UInt(0x80000000))!
 }
 
 @inlinable
 public var HKEY_CURRENT_USER: HKEY {
-  HKEY(bitPattern: UInt(0x80000001))!
+  unsafe HKEY(bitPattern: UInt(0x80000001))!
 }
 
 @inlinable
 public var HKEY_LOCAL_MACHINE: HKEY {
-  HKEY(bitPattern: UInt(0x80000002))!
+  unsafe HKEY(bitPattern: UInt(0x80000002))!
 }
 
 @inlinable
 public var HKEY_USERS: HKEY {
-  HKEY(bitPattern: UInt(0x80000003))!
+  unsafe HKEY(bitPattern: UInt(0x80000003))!
 }
 
 @inlinable
 public var HKEY_PERFORMANCE_DATA: HKEY {
-  HKEY(bitPattern: UInt(0x80000004))!
+  unsafe HKEY(bitPattern: UInt(0x80000004))!
 }
 
 @inlinable
 public var HKEY_PERFORMANCE_TEXT: HKEY {
-  HKEY(bitPattern: UInt(0x80000050))!
+  unsafe HKEY(bitPattern: UInt(0x80000050))!
 }
 
 @inlinable
 public var HKEY_PERFORMANCE_NLSTEXT: HKEY {
-  HKEY(bitPattern: UInt(0x80000060))!
+  unsafe HKEY(bitPattern: UInt(0x80000060))!
 }
 
 @inlinable
 public var HKEY_CURRENT_CONFIG: HKEY {
-  HKEY(bitPattern: UInt(0x80000005))!
+  unsafe HKEY(bitPattern: UInt(0x80000005))!
 }
 
 @inlinable
 public var HKEY_DYN_DATA: HKEY {
-  HKEY(bitPattern: UInt(0x80000006))!
+  unsafe HKEY(bitPattern: UInt(0x80000006))!
 }
 
 @inlinable
 public var HKEY_CURRENT_USER_LOCAL_SETTINGS: HKEY {
-  HKEY(bitPattern: UInt(0x80000007))!
+  unsafe HKEY(bitPattern: UInt(0x80000007))!
 }
 
 // Richedit.h
diff --git a/stdlib/public/core/Array.swift b/stdlib/public/core/Array.swift
index ccec5d1c45a10..bd63bcff26a7f 100644
--- a/stdlib/public/core/Array.swift
+++ b/stdlib/public/core/Array.swift
@@ -355,6 +355,17 @@ extension Array {
     }
   }
 
+#if INTERNAL_CHECKS_ENABLED && COW_CHECKS_ENABLED
+  @_alwaysEmitIntoClient
+  @_semantics("array.make_mutable")
+  @_effects(notEscaping self.**)
+  internal mutating func _makeMutableAndUniqueUnchecked() {
+    if _slowPath(!_buffer.beginCOWMutationUnchecked()) {
+      _buffer = _buffer._consumeAndCreateNew()
+    }
+  }
+#endif
+
   /// Marks the end of an Array mutation.
   ///
   /// After a call to `_endMutation` the buffer must not be mutated until a call
@@ -951,6 +962,7 @@ extension Array: RangeReplaceableCollection {
   /// Entry point for `Array` literal construction; builds and returns
   /// an Array of `count` uninitialized elements.
   @inlinable
+  @unsafe
   @_semantics("array.uninitialized")
   internal static func _allocateUninitialized(
     _ count: Int
@@ -966,6 +978,7 @@ extension Array: RangeReplaceableCollection {
   ///
   /// - Precondition: `storage is _ContiguousArrayStorage`.
   @inlinable
+  @unsafe
   @_semantics("array.uninitialized")
   @_effects(escaping storage => return.0.value**)
   @_effects(escaping storage.class*.value** => return.0.value**.class*.value**)
@@ -1496,15 +1509,36 @@ extension Array {
 }
 
 extension Array {
-  /// Implementation for Array(unsafeUninitializedCapacity:initializingWith:)
+#if !$Embedded
+  /// Implementation preserved (for ABI reasons) for:
+  /// Array(unsafeUninitializedCapacity:initializingWith:)
   /// and ContiguousArray(unsafeUninitializedCapacity:initializingWith:)
-  @inlinable
+  /*@_spi(SwiftStdlibLegacyABI)*/ @available(swift, obsoleted: 1)
+  @inlinable // inlinable is necessary for prespecialization
   internal init(
     _unsafeUninitializedCapacity: Int,
     initializingWith initializer: (
       _ buffer: inout UnsafeMutableBufferPointer<Element>,
       _ initializedCount: inout Int) throws -> Void
   ) rethrows {
+    try unsafe self.init(
+      _unsafeUninitializedCapacity: _unsafeUninitializedCapacity,
+      initializingWithTypedThrowsInitializer: initializer
+    )
+  }
+#endif
+
+  /// Implementation for:
+  /// Array(unsafeUninitializedCapacity:initializingWith:)
+  /// and ContiguousArray(unsafeUninitializedCapacity:initializingWith:)
+  @_alwaysEmitIntoClient
+  internal init<E: Error>(
+    _unsafeUninitializedCapacity: Int,
+    initializingWithTypedThrowsInitializer initializer: (
+      _ buffer: inout UnsafeMutableBufferPointer<Element>,
+      _ initializedCount: inout Int
+    ) throws(E) -> Void
+  ) throws(E) {
     var firstElementAddress: UnsafeMutablePointer<Element>
     unsafe (self, firstElementAddress) =
       unsafe Array._allocateUninitialized(_unsafeUninitializedCapacity)
@@ -1554,22 +1588,24 @@ extension Array {
   ///         which begins as zero. Set `initializedCount` to the number of
   ///         elements you initialize.
   @_alwaysEmitIntoClient @inlinable
-  public init(
+  public init<E: Error>(
     unsafeUninitializedCapacity: Int,
     initializingWith initializer: (
       _ buffer: inout UnsafeMutableBufferPointer<Element>,
-      _ initializedCount: inout Int) throws -> Void
-  ) rethrows {
+      _ initializedCount: inout Int
+    ) throws(E) -> Void
+  ) throws(E) {
     self = try unsafe Array(
       _unsafeUninitializedCapacity: unsafeUninitializedCapacity,
-      initializingWith: initializer)
+      initializingWithTypedThrowsInitializer: initializer
+    )
   }
 
   // Superseded by the typed-throws version of this function, but retained
   // for ABI reasons.
+  @_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
   @usableFromInline
-  @_disfavoredOverload
-  func withUnsafeBufferPointer<R>(
+  internal func withUnsafeBufferPointer<R>(
     _ body: (UnsafeBufferPointer<Element>) throws -> R
   ) rethrows -> R {
     return try unsafe _buffer.withUnsafeBufferPointer(body)
@@ -1731,14 +1767,19 @@ extension Array {
   }
 
   @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
   public var mutableSpan: MutableSpan<Element> {
-    @lifetime(/*inout*/borrow self)
-    @_alwaysEmitIntoClient
+    @lifetime(&self)
     mutating get {
+      // _makeMutableAndUnique*() inserts begin_cow_mutation.
+      // LifetimeDependence analysis inserts call to end_cow_mutation_addr since we cannot schedule it in the stdlib for mutableSpan property.
+#if INTERNAL_CHECKS_ENABLED && COW_CHECKS_ENABLED
+      // We have runtime verification to check if begin_cow_mutation/end_cow_mutation are properly nested in asserts build of stdlib,
+      // disable checking whenever it is turned on since the compiler generated `end_cow_mutation_addr` is conservative and cannot be verified.
+      _makeMutableAndUniqueUnchecked()
+#else
       _makeMutableAndUnique()
-      // NOTE: We don't have the ability to schedule a call to
-      //       ContiguousArrayBuffer.endCOWMutation().
-      //       rdar://146785284 (lifetime analysis for end of mutation)
+#endif
       let pointer = unsafe _buffer.firstElementAddress
       let count = _buffer.mutableCount
       let span = unsafe MutableSpan(_unsafeStart: pointer, count: count)
diff --git a/stdlib/public/core/ArrayBuffer.swift b/stdlib/public/core/ArrayBuffer.swift
index 777d868016eeb..306b9672da87c 100644
--- a/stdlib/public/core/ArrayBuffer.swift
+++ b/stdlib/public/core/ArrayBuffer.swift
@@ -135,7 +135,22 @@ extension _ArrayBuffer {
 #endif
     return isUnique
   }
-  
+
+#if INTERNAL_CHECKS_ENABLED && COW_CHECKS_ENABLED
+   @_alwaysEmitIntoClient
+  internal mutating func beginCOWMutationUnchecked() -> Bool {
+    let isUnique: Bool
+    if !_isClassOrObjCExistential(Element.self) {
+      isUnique = _storage.beginCOWMutationUnflaggedNative()
+    } else if !_storage.beginCOWMutationNative() {
+      return false
+    } else {
+      isUnique = _isNative
+    }
+    return isUnique
+  }
+#endif
+
   /// Puts the buffer in an immutable state.
   ///
   /// - Precondition: The buffer must be mutable or the empty array singleton.
@@ -330,7 +345,7 @@ extension _ArrayBuffer {
       .assumingMemoryBound(to: AnyObject.self)
     let (_, c) = unsafe _nonNative._copyContents(
       initializing: UnsafeMutableBufferPointer(start: ptr, count: buffer.count))
-    return unsafe (IndexingIterator(_elements: self, _position: c), c)
+    return (IndexingIterator(_elements: self, _position: c), c)
   }
 
   /// Returns a `_SliceBuffer` containing the given sub-range of elements in
diff --git a/stdlib/public/core/ArrayBufferProtocol.swift b/stdlib/public/core/ArrayBufferProtocol.swift
index efc5b93088960..463913f6c2922 100644
--- a/stdlib/public/core/ArrayBufferProtocol.swift
+++ b/stdlib/public/core/ArrayBufferProtocol.swift
@@ -76,11 +76,13 @@ where Indices == Range<Int> {
   /// Returns a `_SliceBuffer` containing the elements in `bounds`.
   subscript(bounds: Range<Int>) -> _SliceBuffer<Element> { get }
 
+#if !$Embedded
   // Superseded by the typed-throws version of this function, but retained
   // for ABI reasons.
   func withUnsafeBufferPointer<R>(
     _ body: (UnsafeBufferPointer<Element>) throws -> R
   ) rethrows -> R
+#endif
 
   /// Call `body(p)`, where `p` is an `UnsafeBufferPointer` over the
   /// underlying contiguous storage.  If no such storage exists, it is
@@ -90,11 +92,13 @@ where Indices == Range<Int> {
     _ body: (UnsafeBufferPointer<Element>) throws(E) -> R
   ) throws(E) -> R
 
+#if !$Embedded
   // Superseded by the typed-throws version of this function, but retained
   // for ABI reasons.
   mutating func withUnsafeMutableBufferPointer<R>(
     _ body: (UnsafeMutableBufferPointer<Element>) throws -> R
   ) rethrows -> R
+#endif
 
   /// Call `body(p)`, where `p` is an `UnsafeMutableBufferPointer`
   /// over the underlying contiguous storage.
diff --git a/stdlib/public/core/ArraySlice.swift b/stdlib/public/core/ArraySlice.swift
index 886869b1ec796..5a054b0185a66 100644
--- a/stdlib/public/core/ArraySlice.swift
+++ b/stdlib/public/core/ArraySlice.swift
@@ -169,6 +169,16 @@ extension ArraySlice {
     }
   }
   
+#if INTERNAL_CHECKS_ENABLED && COW_CHECKS_ENABLED
+  @_alwaysEmitIntoClient
+  @_semantics("array.make_mutable")
+  internal mutating func _makeMutableAndUniqueUnchecked() {
+    if _slowPath(!_buffer.beginCOWMutationUnchecked()) {
+      _buffer = _Buffer(copying: _buffer)
+    }
+  }
+#endif
+
   /// Marks the end of a mutation.
   ///
   /// After a call to `_endMutation` the buffer must not be mutated until a call
@@ -1166,9 +1176,9 @@ extension ArraySlice {
 extension ArraySlice {
   // Superseded by the typed-throws version of this function, but retained
   // for ABI reasons.
+  @_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
   @usableFromInline
-  @_disfavoredOverload
-  func withUnsafeBufferPointer<R>(
+  internal func withUnsafeBufferPointer<R>(
     _ body: (UnsafeBufferPointer<Element>) throws -> R
   ) rethrows -> R {
     return try unsafe _buffer.withUnsafeBufferPointer(body)
@@ -1209,18 +1219,24 @@ extension ArraySlice {
   ) throws(E) -> R {
     return try unsafe _buffer.withUnsafeBufferPointer(body)
   }
+}
 
-  @available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension ArraySlice {
+  @available(SwiftCompatibilitySpan 5.0, *)
+  @_alwaysEmitIntoClient
   public var span: Span<Element> {
     @lifetime(borrow self)
-    @_alwaysEmitIntoClient
     borrowing get {
       let (pointer, count) = unsafe (_buffer.firstElementAddress, _buffer.count)
       let span = unsafe Span(_unsafeStart: pointer, count: count)
       return unsafe _overrideLifetime(span, borrowing: self)
     }
   }
+}
 
+extension ArraySlice {
   // Superseded by the typed-throws version of this function, but retained
   // for ABI reasons.
   @_semantics("array.withUnsafeMutableBufferPointer")
@@ -1299,22 +1315,33 @@ extension ArraySlice {
     // Invoke the body.
     return try unsafe body(&inoutBufferPointer)
   }
+}
 
-  @available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension ArraySlice {
+  @_alwaysEmitIntoClient
   public var mutableSpan: MutableSpan<Element> {
-    @lifetime(/*inout*/borrow self)
-    @_alwaysEmitIntoClient
+    @lifetime(&self)
     mutating get {
+      // _makeMutableAndUnique*() inserts begin_cow_mutation.
+      // LifetimeDependence analysis inserts call to end_cow_mutation_addr since we cannot schedule it in the stdlib for mutableSpan property.
+#if INTERNAL_CHECKS_ENABLED && COW_CHECKS_ENABLED
+      // We have runtime verification to check if begin_cow_mutation/end_cow_mutation are properly nested in asserts build of stdlib,
+      // disable checking whenever it is turned on since the compiler generated `end_cow_mutation_addr` is conservative and cannot be verified.
+      _makeMutableAndUniqueUnchecked()
+#else
       _makeMutableAndUnique()
-      // NOTE: We don't have the ability to schedule a call to
-      //       ContiguousArrayBuffer.endCOWMutation().
-      //       rdar://146785284 (lifetime analysis for end of mutation)
+#endif
+      // LifetimeDependence analysis inserts call to Builtin.endCOWMutation.
       let (pointer, count) = unsafe (_buffer.firstElementAddress, _buffer.count)
       let span = unsafe MutableSpan(_unsafeStart: pointer, count: count)
       return unsafe _overrideLifetime(span, mutating: &self)
     }
   }
+}
 
+extension ArraySlice {
   @inlinable
   public __consuming func _copyContents(
     initializing buffer: UnsafeMutableBufferPointer<Element>
diff --git a/stdlib/public/core/Availability.swift b/stdlib/public/core/Availability.swift
index 0ed46931dd2ca..08880a2ee57d5 100644
--- a/stdlib/public/core/Availability.swift
+++ b/stdlib/public/core/Availability.swift
@@ -240,9 +240,11 @@ extension _SwiftStdlibVersion {
   public static var v6_1_0: Self { Self(_value: 0x060100) }
   @_alwaysEmitIntoClient
   public static var v6_2_0: Self { Self(_value: 0x060200) }
+  @_alwaysEmitIntoClient
+  public static var v6_3_0: Self { Self(_value: 0x060300) }
 
   @available(SwiftStdlib 5.7, *)
-  public static var current: Self { .v6_2_0 }
+  public static var current: Self { .v6_3_0 }
 }
 
 @available(SwiftStdlib 5.7, *)
diff --git a/stdlib/public/core/Bitset.swift b/stdlib/public/core/Bitset.swift
index 1d38caf2a5a43..300e05e9dcffb 100644
--- a/stdlib/public/core/Bitset.swift
+++ b/stdlib/public/core/Bitset.swift
@@ -45,7 +45,7 @@ extension _UnsafeBitset {
     _internalInvariant(element >= 0)
     // Note: We perform on UInts to get faster unsigned math (shifts).
     let element = UInt(bitPattern: element)
-    let capacity = unsafe UInt(bitPattern: Word.capacity)
+    let capacity = UInt(bitPattern: Word.capacity)
     return Int(bitPattern: element / capacity)
   }
 
@@ -55,7 +55,7 @@ extension _UnsafeBitset {
     _internalInvariant(element >= 0)
     // Note: We perform on UInts to get faster unsigned math (masking).
     let element = UInt(bitPattern: element)
-    let capacity = unsafe UInt(bitPattern: Word.capacity)
+    let capacity = UInt(bitPattern: Word.capacity)
     return Int(bitPattern: element % capacity)
   }
 
@@ -68,8 +68,8 @@ extension _UnsafeBitset {
   @inlinable
   @inline(__always)
   internal static func join(word: Int, bit: Int) -> Int {
-    unsafe _internalInvariant(bit >= 0 && bit < Word.capacity)
-    return unsafe word &* Word.capacity &+ bit
+    _internalInvariant(bit >= 0 && bit < Word.capacity)
+    return word &* Word.capacity &+ bit
   }
 }
 
@@ -84,7 +84,7 @@ extension _UnsafeBitset {
   internal var capacity: Int {
     @inline(__always)
     get {
-      return unsafe wordCount &* Word.capacity
+      return wordCount &* Word.capacity
     }
   }
 
@@ -199,7 +199,7 @@ extension _UnsafeBitset {
 
     @inlinable
     internal init(_ value: UInt) {
-      unsafe self.value = value
+      self.value = value
     }
   }
 }
@@ -217,7 +217,7 @@ extension _UnsafeBitset.Word {
   @inline(__always)
   internal func uncheckedContains(_ bit: Int) -> Bool {
     _internalInvariant(bit >= 0 && bit < UInt.bitWidth)
-    return unsafe value & (1 &<< bit) != 0
+    return value & (1 &<< bit) != 0
   }
 
   @inlinable
@@ -226,8 +226,8 @@ extension _UnsafeBitset.Word {
   internal mutating func uncheckedInsert(_ bit: Int) -> Bool {
     _internalInvariant(bit >= 0 && bit < UInt.bitWidth)
     let mask: UInt = 1 &<< bit
-    let inserted = unsafe value & mask == 0
-    unsafe value |= mask
+    let inserted = value & mask == 0
+    value |= mask
     return inserted
   }
 
@@ -237,8 +237,8 @@ extension _UnsafeBitset.Word {
   internal mutating func uncheckedRemove(_ bit: Int) -> Bool {
     _internalInvariant(bit >= 0 && bit < UInt.bitWidth)
     let mask: UInt = 1 &<< bit
-    let removed = unsafe value & mask != 0
-    unsafe value &= ~mask
+    let removed = value & mask != 0
+    value &= ~mask
     return removed
   }
 }
@@ -248,8 +248,8 @@ extension _UnsafeBitset.Word {
   var minimum: Int? {
     @inline(__always)
     get {
-      guard unsafe value != 0 else { return nil }
-      return unsafe value.trailingZeroBitCount
+      guard value != 0 else { return nil }
+      return value.trailingZeroBitCount
     }
   }
 
@@ -257,8 +257,8 @@ extension _UnsafeBitset.Word {
   var maximum: Int? {
     @inline(__always)
     get {
-      guard unsafe value != 0 else { return nil }
-      return unsafe _UnsafeBitset.Word.capacity &- 1 &- value.leadingZeroBitCount
+      guard value != 0 else { return nil }
+      return _UnsafeBitset.Word.capacity &- 1 &- value.leadingZeroBitCount
     }
   }
 
@@ -266,32 +266,32 @@ extension _UnsafeBitset.Word {
   var complement: _UnsafeBitset.Word {
     @inline(__always)
     get {
-      return unsafe _UnsafeBitset.Word(~value)
+      return _UnsafeBitset.Word(~value)
     }
   }
 
   @inlinable
   @inline(__always)
   internal func subtracting(elementsBelow bit: Int) -> _UnsafeBitset.Word {
-    unsafe _internalInvariant(bit >= 0 && bit < _UnsafeBitset.Word.capacity)
+    _internalInvariant(bit >= 0 && bit < _UnsafeBitset.Word.capacity)
     let mask = UInt.max &<< bit
-    return unsafe _UnsafeBitset.Word(value & mask)
+    return _UnsafeBitset.Word(value & mask)
   }
 
   @inlinable
   @inline(__always)
   internal func intersecting(elementsBelow bit: Int) -> _UnsafeBitset.Word {
-    unsafe _internalInvariant(bit >= 0 && bit < _UnsafeBitset.Word.capacity)
+    _internalInvariant(bit >= 0 && bit < _UnsafeBitset.Word.capacity)
     let mask: UInt = (1 as UInt &<< bit) &- 1
-    return unsafe _UnsafeBitset.Word(value & mask)
+    return _UnsafeBitset.Word(value & mask)
   }
 
   @inlinable
   @inline(__always)
   internal func intersecting(elementsAbove bit: Int) -> _UnsafeBitset.Word {
-    unsafe _internalInvariant(bit >= 0 && bit < _UnsafeBitset.Word.capacity)
+    _internalInvariant(bit >= 0 && bit < _UnsafeBitset.Word.capacity)
     let mask = (UInt.max &<< bit) &<< 1
-    return unsafe _UnsafeBitset.Word(value & mask)
+    return _UnsafeBitset.Word(value & mask)
   }
 }
 
@@ -300,7 +300,7 @@ extension _UnsafeBitset.Word {
   internal static var empty: _UnsafeBitset.Word {
     @inline(__always)
     get {
-      return unsafe _UnsafeBitset.Word(0)
+      return _UnsafeBitset.Word(0)
     }
   }
 
@@ -308,7 +308,7 @@ extension _UnsafeBitset.Word {
   internal static var allBits: _UnsafeBitset.Word {
     @inline(__always)
     get {
-      return unsafe _UnsafeBitset.Word(UInt.max)
+      return _UnsafeBitset.Word(UInt.max)
     }
   }
 }
@@ -324,19 +324,19 @@ extension _UnsafeBitset.Word: @unsafe Sequence, @unsafe IteratorProtocol {
 
   @inlinable
   internal var count: Int {
-    return unsafe value.nonzeroBitCount
+    return value.nonzeroBitCount
   }
 
   @inlinable
   internal var underestimatedCount: Int {
-    return unsafe count
+    return count
   }
 
   @inlinable
   internal var isEmpty: Bool {
     @inline(__always)
     get {
-      return unsafe value == 0
+      return value == 0
     }
   }
 
@@ -344,9 +344,9 @@ extension _UnsafeBitset.Word: @unsafe Sequence, @unsafe IteratorProtocol {
   /// and also destructively clear it.
   @inlinable
   internal mutating func next() -> Int? {
-    guard unsafe value != 0 else { return nil }
-    let bit = unsafe value.trailingZeroBitCount
-    unsafe value &= value &- 1       // Clear lowest nonzero bit.
+    guard value != 0 else { return nil }
+    let bit = value.trailingZeroBitCount
+    value &= value &- 1       // Clear lowest nonzero bit.
     return bit
   }
 }
diff --git a/stdlib/public/core/Bool.swift b/stdlib/public/core/Bool.swift
index 827fea8b50ebf..cc40504360269 100644
--- a/stdlib/public/core/Bool.swift
+++ b/stdlib/public/core/Bool.swift
@@ -197,7 +197,6 @@ extension Bool: Hashable {
   }
 }
 
-@_unavailableInEmbedded
 extension Bool: LosslessStringConvertible {
   /// Creates a new Boolean value from the given string.
   ///
diff --git a/stdlib/public/core/BridgeObjectiveC.swift b/stdlib/public/core/BridgeObjectiveC.swift
index a58c1e3965a38..bca583ee7b06f 100644
--- a/stdlib/public/core/BridgeObjectiveC.swift
+++ b/stdlib/public/core/BridgeObjectiveC.swift
@@ -716,19 +716,19 @@ public func swift_unboxFromSwiftValueWithType<T>(
 
   if source === _nullPlaceholder {
     if let unpacked = Optional<Any>.none as? T {
-      result.initialize(to: unpacked)
+      unsafe result.initialize(to: unpacked)
       return true
     }
   }
     
   if let box = source as? __SwiftValue {
     if let value = box.value as? T {
-      result.initialize(to: value)
+      unsafe result.initialize(to: value)
       return true
     }
   } else if let box = source as? _NSSwiftValue {
     if let value = box.value as? T {
-      result.initialize(to: value)
+      unsafe result.initialize(to: value)
       return true
     }
   }
@@ -819,7 +819,7 @@ public func _bridgeAnythingToObjectiveC<T>(_ x: T) -> AnyObject {
 
   if !done {
     if type(of: source) as? AnyClass != nil {
-      result = unsafeBitCast(x, to: AnyObject.self)
+      result = unsafe unsafeBitCast(x, to: AnyObject.self)
     } else if let object = _bridgeToObjectiveCUsingProtocolIfPossible(source) {
       result = object
     } else {
diff --git a/stdlib/public/core/Builtin.swift b/stdlib/public/core/Builtin.swift
index a2bea81aec659..c7533092e5a71 100644
--- a/stdlib/public/core/Builtin.swift
+++ b/stdlib/public/core/Builtin.swift
@@ -175,7 +175,15 @@ public func == (
   case (.none, .none):
     return true
   case let (.some(ty0), .some(ty1)):
+#if compiler(>=5.3) && $GeneralizedIsSameMetaTypeBuiltin
     return Bool(Builtin.is_same_metatype(ty0, ty1))
+#else
+    // FIXME: Remove this branch once all supported compilers understand the
+    // generalized is_same_metatype builtin
+    let p1 = unsafeBitCast(ty0, to: UnsafeRawPointer.self)
+    let p2 = unsafeBitCast(ty1, to: UnsafeRawPointer.self)
+    return p1 == p2
+#endif
   default:
     return false
   }
diff --git a/stdlib/public/core/CMakeLists.txt b/stdlib/public/core/CMakeLists.txt
index 4f58c0a2172ff..7146ea7f6c82f 100644
--- a/stdlib/public/core/CMakeLists.txt
+++ b/stdlib/public/core/CMakeLists.txt
@@ -57,7 +57,6 @@ split_embedded_sources(
   EMBEDDED CollectionAlgorithms.swift
   EMBEDDED Comparable.swift
   EMBEDDED CompilerProtocols.swift
-  EMBEDDED SwiftSettings.swift
   EMBEDDED Sendable.swift
   EMBEDDED ContiguousArray.swift
   EMBEDDED ContiguouslyStored.swift
@@ -159,6 +158,8 @@ split_embedded_sources(
   EMBEDDED Sort.swift
   EMBEDDED Span/MutableRawSpan.swift
   EMBEDDED Span/MutableSpan.swift
+  EMBEDDED Span/OutputRawSpan.swift
+  EMBEDDED Span/OutputSpan.swift
   EMBEDDED Span/RawSpan.swift
   EMBEDDED Span/Span.swift
   EMBEDDED StaticString.swift
@@ -214,6 +215,13 @@ split_embedded_sources(
   EMBEDDED UnsafeRawPointer.swift
   EMBEDDED UTFEncoding.swift
   EMBEDDED UTF8.swift
+  EMBEDDED UTF8EncodingError.swift
+  EMBEDDED UTF8Span.swift
+  EMBEDDED UTF8SpanBits.swift
+  EMBEDDED UTF8SpanComparisons.swift
+  EMBEDDED UTF8SpanFundamentals.swift
+  EMBEDDED UTF8SpanInternalHelpers.swift
+  EMBEDDED UTF8SpanIterators.swift
   EMBEDDED UTF16.swift
   EMBEDDED UTF32.swift
   EMBEDDED Unicode.swift # ORDER DEPENDENCY: must follow new unicode support
@@ -252,7 +260,7 @@ split_embedded_sources(
   OUT_LIST_NORMAL SWIFTLIB_GYB_SOURCES
 
     NORMAL AtomicInt.swift.gyb
-    NORMAL FloatingPointParsing.swift.gyb
+  EMBEDDED FloatingPointParsing.swift.gyb
   EMBEDDED FloatingPointTypes.swift.gyb
   EMBEDDED IntegerTypes.swift.gyb
   EMBEDDED LegacyInt128.swift.gyb
@@ -262,15 +270,25 @@ split_embedded_sources(
   )
 
 if(SWIFT_STDLIB_ENABLE_VECTOR_TYPES)
+  split_embedded_sources(
+    OUT_LIST_EMBEDDED SWIFTLIB_EMBEDDED_VECTOR_GYB_SOURCES
+    OUT_LIST_NORMAL SWIFTLIB_VECTOR_GYB_SOURCES
+    
+    EMBEDDED SIMDIntegerConcreteOperations.swift.gyb
+    EMBEDDED SIMDFloatConcreteOperations.swift.gyb
+    EMBEDDED SIMDMaskConcreteOperations.swift.gyb
+    EMBEDDED SIMDVectorTypes.swift.gyb
+  )
+
   list(APPEND SWIFTLIB_SOURCES SIMDVector.swift)
-  list(APPEND SWIFTLIB_GYB_SOURCES SIMDConcreteOperations.swift.gyb SIMDVectorTypes.swift.gyb)
+  list(APPEND SWIFTLIB_GYB_SOURCES ${SWIFTLIB_VECTOR_GYB_SOURCES})
 
   list(APPEND SWIFTLIB_EMBEDDED_SOURCES SIMDVector.swift)
-  list(APPEND SWIFTLIB_EMBEDDED_GYB_SOURCES SIMDConcreteOperations.swift.gyb SIMDVectorTypes.swift.gyb)
+  list(APPEND SWIFTLIB_EMBEDDED_GYB_SOURCES ${SWIFTLIB_EMBEDDED_VECTOR_GYB_SOURCES})
 endif()
 
 # Freestanding and Linux/Android builds both have failures to resolve.
-if(NOT BOOTSTRAPPING_MODE STREQUAL "OFF" AND NOT SWIFT_FREESTANDING_FLAVOR AND NOT SWIFT_HOST_VARIANT_SDK STREQUAL "LINUX" AND NOT SWIFT_HOST_VARIANT_SDK STREQUAL "ANDROID")
+if(NOT BOOTSTRAPPING_MODE STREQUAL "OFF" AND NOT SWIFT_FREESTANDING_FLAVOR AND NOT SWIFT_HOST_VARIANT_SDK STREQUAL "ANDROID")
   list(APPEND SWIFTLIB_SOURCES ObjectIdentifier+DebugDescription.swift)
 endif()
 
@@ -326,6 +344,7 @@ list(APPEND swift_stdlib_compile_flags "-enable-experimental-feature" "BitwiseCo
 list(APPEND swift_stdlib_compile_flags "-enable-experimental-feature" "ValueGenerics")
 list(APPEND swift_stdlib_compile_flags "-enable-experimental-feature" "AddressableParameters")
 list(APPEND swift_stdlib_compile_flags "-enable-experimental-feature" "AddressableTypes")
+list(APPEND swift_stdlib_compile_flags "-enable-experimental-feature" "AllowUnsafeAttribute")
 list(APPEND swift_stdlib_compile_flags "-strict-memory-safety")
 
 if("${SWIFT_NATIVE_SWIFT_TOOLS_PATH}" STREQUAL "")
@@ -457,15 +476,15 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   foreach(sdk ${SWIFT_SDKS})
     set(lib_dir "${SWIFT_SDK_${sdk}_LIB_SUBDIR}")
     set(lib_path "${SWIFTLIB_DIR}/${lib_dir}")
-    set(compat_lib_name "${lib_path}/libswiftCompatibilitySpan.dylib")
 
     # This doesn't depend on libswiftCore.dylib because we don't actually need
     # for it to exist to create the symlink, nor is there any need to recreate
     # the symlink if the dylib changes.
     add_custom_command_target(unused_var
                               CUSTOM_TARGET_NAME "swiftCompatibilitySpan-symlink-${lib_dir}"
-                              OUTPUT "${compat_lib_name}"
-                              COMMAND ${CMAKE_COMMAND} "-E" "create_symlink" "${lib_path}/libswiftCore.dylib" "${compat_lib_name}")
+                              OUTPUT "${lib_path}/libswiftCompatibilitySpan.dylib"
+                              COMMAND ${CMAKE_COMMAND} "-E" "create_symlink" "libswiftCore.dylib" "libswiftCompatibilitySpan.dylib"
+                              WORKING_DIRECTORY ${lib_path})
     foreach(ARCH ${SWIFT_SDK_${sdk}_ARCHITECTURES})
       add_dependencies("swiftCore-${lib_dir}-${ARCH}" "swiftCompatibilitySpan-symlink-${lib_dir}")
     endforeach()
@@ -517,7 +536,6 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
       GYB_SOURCES ${SWIFTLIB_EMBEDDED_GYB_SOURCES}
       SWIFT_COMPILE_FLAGS
         ${swift_stdlib_compile_flags} -Xcc -ffreestanding -enable-experimental-feature Embedded
-        -Xfrontend -enable-ossa-modules
       MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
       SDK "embedded"
       ARCHITECTURE "${arch}"
diff --git a/stdlib/public/core/CTypes.swift b/stdlib/public/core/CTypes.swift
index 20ecba2bcf9bb..2b3f2ff0bc90d 100644
--- a/stdlib/public/core/CTypes.swift
+++ b/stdlib/public/core/CTypes.swift
@@ -114,10 +114,10 @@ public typealias CLongDouble = Double
 #error("CLongDouble needs to be defined for this OpenBSD architecture")
 #endif
 #elseif os(FreeBSD)
+// On FreeBSD, long double is Float128 for arm64, which we don't have yet in
+// Swift
 #if arch(x86_64) || arch(i386)
 public typealias CLongDouble = Float80
-#else
-#error("CLongDouble needs to be defined for this FreeBSD architecture")
 #endif
 #elseif $Embedded
 #if arch(x86_64) || arch(i386)
@@ -314,7 +314,7 @@ public struct CVaListPointer {
        __vr_top: UnsafeMutablePointer<Int>?,
        __gr_off: Int32,
        __vr_off: Int32) {
-    _value = (__stack, __gr_top, __vr_top, __gr_off, __vr_off)
+    unsafe _value = (__stack, __gr_top, __vr_top, __gr_off, __vr_off)
   }
 }
 
@@ -322,11 +322,11 @@ public struct CVaListPointer {
 extension CVaListPointer: CustomDebugStringConvertible {
   @safe
   public var debugDescription: String {
-    return "(\(_value.__stack.debugDescription), " +
-           "\(_value.__gr_top.debugDescription), " +
-           "\(_value.__vr_top.debugDescription), " +
-           "\(_value.__gr_off), " +
-           "\(_value.__vr_off))"
+    return "(\(unsafe _value.__stack.debugDescription), " +
+           "\(unsafe _value.__gr_top.debugDescription), " +
+           "\(unsafe _value.__vr_top.debugDescription), " +
+           "\(unsafe _value.__gr_off), " +
+           "\(unsafe _value.__vr_off))"
   }
 }
 
diff --git a/stdlib/public/core/ClosedRange.swift b/stdlib/public/core/ClosedRange.swift
index 430f9b02ba549..7b6b5a1991805 100644
--- a/stdlib/public/core/ClosedRange.swift
+++ b/stdlib/public/core/ClosedRange.swift
@@ -129,6 +129,7 @@ extension ClosedRange: RangeExpression {
   /// - Returns: `true` if `element` is contained in the range; otherwise,
   ///   `false`.
   @inlinable
+  @inline(__always)
   public func contains(_ element: Bound) -> Bool {
     return element >= self.lowerBound && element <= self.upperBound
   }
@@ -383,6 +384,7 @@ extension ClosedRange {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
+  @_transparent
   public func contains(_ other: ClosedRange<Bound>) -> Bool {
     lowerBound <= other.lowerBound && upperBound >= other.upperBound
   }
diff --git a/stdlib/public/core/Collection.swift b/stdlib/public/core/Collection.swift
index b56f3d15b9d6d..1e2b88ab2a99c 100644
--- a/stdlib/public/core/Collection.swift
+++ b/stdlib/public/core/Collection.swift
@@ -1213,6 +1213,7 @@ extension Collection {
     return Array(result)
   }
 
+#if !$Embedded
   // ABI-only entrypoint for the rethrows version of map, which has been
   // superseded by the typed-throws version. Expressed as "throws", which is
   // ABI-compatible with "rethrows".
@@ -1224,6 +1225,7 @@ extension Collection {
   ) throws -> [T] {
     try map(transform)
   }
+#endif
 
   /// Returns a subsequence containing all but the given number of initial
   /// elements.
diff --git a/stdlib/public/core/CollectionAlgorithms.swift b/stdlib/public/core/CollectionAlgorithms.swift
index ce14eb793a798..3dab3d5ee89d4 100644
--- a/stdlib/public/core/CollectionAlgorithms.swift
+++ b/stdlib/public/core/CollectionAlgorithms.swift
@@ -402,7 +402,7 @@ extension MutableCollection where Self: BidirectionalCollection {
       (bufferPointer) -> Int in
       let unsafeBufferPivot = try unsafe bufferPointer._partitionImpl(
         by: belongsInSecondPartition)
-      return unsafe unsafeBufferPivot - bufferPointer.startIndex
+      return unsafeBufferPivot - bufferPointer.startIndex
     }
     if let offset = maybeOffset {
       return index(startIndex, offsetBy: offset)
diff --git a/stdlib/public/core/CollectionOfOne.swift b/stdlib/public/core/CollectionOfOne.swift
index 702f26313266d..19321e303e0bd 100644
--- a/stdlib/public/core/CollectionOfOne.swift
+++ b/stdlib/public/core/CollectionOfOne.swift
@@ -159,14 +159,29 @@ extension CollectionOfOne: RandomAccessCollection, MutableCollection {
   }
 }
 
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension CollectionOfOne {
 
-  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
   public var span: Span<Element> {
     @lifetime(borrow self)
-    @_alwaysEmitIntoClient
     get {
-      fatalError("Span over CollectionOfOne is not supported yet.")
+      let pointer = unsafe UnsafePointer<Element>(Builtin.addressOfBorrow(self))
+      let span = unsafe Span(_unsafeStart: pointer, count: 1)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+  }
+
+  @_alwaysEmitIntoClient
+  public var mutableSpan: MutableSpan<Element> {
+    @lifetime(&self)
+    mutating get {
+      let pointer = unsafe UnsafeMutablePointer<Element>(
+        Builtin.addressOfBorrow(self)
+      )
+      let span = unsafe MutableSpan(_unsafeStart: pointer, count: 1)
+      return unsafe _overrideLifetime(span, mutating: &self)
     }
   }
 }
diff --git a/stdlib/public/core/CompilerProtocols.swift b/stdlib/public/core/CompilerProtocols.swift
index c716fa1b09c85..a1b38045d0fc9 100644
--- a/stdlib/public/core/CompilerProtocols.swift
+++ b/stdlib/public/core/CompilerProtocols.swift
@@ -149,6 +149,7 @@ public protocol RawRepresentable<RawValue> {
 ///   - lhs: A raw-representable instance.
 ///   - rhs: A second raw-representable instance.
 @inlinable // trivial-implementation
+@_semantics("rawrepresentable.is_equal")
 public func == <T: RawRepresentable>(lhs: T, rhs: T) -> Bool
   where T.RawValue: Equatable {
   return lhs.rawValue == rhs.rawValue
diff --git a/stdlib/public/core/ContiguousArray.swift b/stdlib/public/core/ContiguousArray.swift
index 13b50082e7556..a5f66fe850f81 100644
--- a/stdlib/public/core/ContiguousArray.swift
+++ b/stdlib/public/core/ContiguousArray.swift
@@ -74,6 +74,16 @@ extension ContiguousArray {
     }
   }
 
+#if INTERNAL_CHECKS_ENABLED && COW_CHECKS_ENABLED
+  @_alwaysEmitIntoClient
+  @_semantics("array.make_mutable")
+  internal mutating func _makeMutableAndUniqueUnchecked() {
+    if _slowPath(!_buffer.beginCOWMutationUnchecked()) {
+      _buffer = _buffer._consumeAndCreateNew()
+    }
+  }
+#endif
+
   /// Marks the end of an Array mutation.
   ///
   /// After a call to `_endMutation` the buffer must not be mutated until a call
@@ -1095,22 +1105,22 @@ extension ContiguousArray {
   ///         which begins as zero. Set `initializedCount` to the number of
   ///         elements you initialize.
   @_alwaysEmitIntoClient @inlinable
-  public init(
+  public init<E>(
     unsafeUninitializedCapacity: Int,
     initializingWith initializer: (
       _ buffer: inout UnsafeMutableBufferPointer<Element>,
-      _ initializedCount: inout Int) throws -> Void
-  ) rethrows {
+      _ initializedCount: inout Int) throws(E) -> Void
+  ) throws(E) {
     self = try unsafe ContiguousArray(Array(
       _unsafeUninitializedCapacity: unsafeUninitializedCapacity,
-      initializingWith: initializer))
+      initializingWithTypedThrowsInitializer: initializer))
   }
 
   // Superseded by the typed-throws version of this function, but retained
   // for ABI reasons.
+  @_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
   @usableFromInline
-  @_disfavoredOverload
-  func withUnsafeBufferPointer<R>(
+  internal func withUnsafeBufferPointer<R>(
     _ body: (UnsafeBufferPointer<Element>) throws -> R
   ) rethrows -> R {
     return try unsafe _buffer.withUnsafeBufferPointer(body)
@@ -1151,11 +1161,14 @@ extension ContiguousArray {
   ) throws(E) -> R {
     return try unsafe _buffer.withUnsafeBufferPointer(body)
   }
+}
 
-  @available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension ContiguousArray {
+  @_alwaysEmitIntoClient
   public var span: Span<Element> {
     @lifetime(borrow self)
-    @_alwaysEmitIntoClient
     borrowing get {
       let pointer = unsafe _buffer.firstElementAddress
       let count = _buffer.immutableCount
@@ -1163,7 +1176,9 @@ extension ContiguousArray {
       return unsafe _overrideLifetime(span, borrowing: self)
     }
   }
+}
 
+extension ContiguousArray {
   // Superseded by the typed-throws version of this function, but retained
   // for ABI reasons.
   @_semantics("array.withUnsafeMutableBufferPointer")
@@ -1241,23 +1256,33 @@ extension ContiguousArray {
     // Invoke the body.
     return try unsafe body(&inoutBufferPointer)
   }
+}
 
-  @available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension ContiguousArray {
+  @_alwaysEmitIntoClient
   public var mutableSpan: MutableSpan<Element> {
-    @lifetime(/*inout*/borrow self)
-    @_alwaysEmitIntoClient
+    @lifetime(&self)
     mutating get {
+      // _makeMutableAndUnique*() inserts begin_cow_mutation.
+      // LifetimeDependence analysis inserts call to end_cow_mutation_addr since we cannot schedule it in the stdlib for mutableSpan property.
+#if INTERNAL_CHECKS_ENABLED && COW_CHECKS_ENABLED
+      // We have runtime verification to check if begin_cow_mutation/end_cow_mutation are properly nested in asserts build of stdlib,
+      // disable checking whenever it is turned on since the compiler generated `end_cow_mutation_addr` is conservative and cannot be verified.
+      _makeMutableAndUniqueUnchecked()
+#else
       _makeMutableAndUnique()
-      // NOTE: We don't have the ability to schedule a call to
-      //       ContiguousArrayBuffer.endCOWMutation().
-      //       rdar://146785284 (lifetime analysis for end of mutation)
+#endif
       let pointer = unsafe _buffer.firstElementAddress
       let count = _buffer.mutableCount
       let span = unsafe MutableSpan(_unsafeStart: pointer, count: count)
       return unsafe _overrideLifetime(span, mutating: &self)
     }
   }
+}
 
+extension ContiguousArray {
   @inlinable
   public __consuming func _copyContents(
     initializing buffer: UnsafeMutableBufferPointer<Element>
diff --git a/stdlib/public/core/ContiguousArrayBuffer.swift b/stdlib/public/core/ContiguousArrayBuffer.swift
index f49d15fb5afb1..ab4ac715a80ef 100644
--- a/stdlib/public/core/ContiguousArrayBuffer.swift
+++ b/stdlib/public/core/ContiguousArrayBuffer.swift
@@ -141,6 +141,7 @@ internal final class _ContiguousArrayStorage<
 
 #if _runtime(_ObjC)
   
+  @_effects(releasenone)
   internal final override func withUnsafeBufferOfObjects<R>(
     _ body: (UnsafeBufferPointer<AnyObject>) throws -> R
   ) rethrows -> R {
@@ -818,6 +819,16 @@ internal struct _ContiguousArrayBuffer<Element>: _ArrayBufferProtocol {
     return false;
   }
 
+#if INTERNAL_CHECKS_ENABLED && COW_CHECKS_ENABLED
+ @_alwaysEmitIntoClient
+  internal mutating func beginCOWMutationUnchecked() -> Bool {
+    if Bool(Builtin.beginCOWMutation(&_storage)) {
+      return true
+    }
+    return false;
+  }
+#endif
+
   /// Puts the buffer in an immutable state.
   ///
   /// - Precondition: The buffer must be mutable or the empty array singleton.
diff --git a/stdlib/public/core/ContiguouslyStored.swift b/stdlib/public/core/ContiguouslyStored.swift
index 340ebd3313624..5f303f258f5a5 100644
--- a/stdlib/public/core/ContiguouslyStored.swift
+++ b/stdlib/public/core/ContiguouslyStored.swift
@@ -42,7 +42,7 @@ extension Array: _HasContiguousBytes {
   }
 }
 extension ContiguousArray: _HasContiguousBytes {}
-extension UnsafeBufferPointer: _HasContiguousBytes {
+extension UnsafeBufferPointer: @unsafe _HasContiguousBytes {
   @inlinable @inline(__always)
   @safe
   func withUnsafeBytes<R>(
@@ -53,7 +53,7 @@ extension UnsafeBufferPointer: _HasContiguousBytes {
     return try unsafe body(UnsafeRawBufferPointer(start: ptr, count: len))
   }
 }
-extension UnsafeMutableBufferPointer: _HasContiguousBytes {
+extension UnsafeMutableBufferPointer: @unsafe _HasContiguousBytes {
   @inlinable @inline(__always)
   @safe
   func withUnsafeBytes<R>(
@@ -64,7 +64,7 @@ extension UnsafeMutableBufferPointer: _HasContiguousBytes {
     return try unsafe body(UnsafeRawBufferPointer(start: ptr, count: len))
   }
 }
-extension UnsafeRawBufferPointer: _HasContiguousBytes {
+extension UnsafeRawBufferPointer: @unsafe _HasContiguousBytes {
   @inlinable @inline(__always)
   @safe
   func withUnsafeBytes<R>(
@@ -73,7 +73,7 @@ extension UnsafeRawBufferPointer: _HasContiguousBytes {
     return try unsafe body(self)
   }
 }
-extension UnsafeMutableRawBufferPointer: _HasContiguousBytes {
+extension UnsafeMutableRawBufferPointer: @unsafe _HasContiguousBytes {
   @inlinable @inline(__always)
   @safe
   func withUnsafeBytes<R>(
diff --git a/stdlib/public/core/DebuggerSupport.swift b/stdlib/public/core/DebuggerSupport.swift
index 62a3fd5723675..93efe80075c8b 100644
--- a/stdlib/public/core/DebuggerSupport.swift
+++ b/stdlib/public/core/DebuggerSupport.swift
@@ -158,7 +158,7 @@ public enum _DebuggerSupport {
       default:
         return value.map(String.init(reflecting:))
       }
-    case .`class`?:
+    case .`class`?, .foreignReference?:
       switch value {
       case let x as CustomDebugStringConvertible:
         return x.debugDescription
diff --git a/stdlib/public/core/Dictionary.swift b/stdlib/public/core/Dictionary.swift
index 6661feb56bb6e..6e867aedec522 100644
--- a/stdlib/public/core/Dictionary.swift
+++ b/stdlib/public/core/Dictionary.swift
@@ -838,7 +838,7 @@ extension Dictionary: ExpressibleByDictionaryLiteral {
     for (key, value) in elements {
       let (bucket, found) = native.find(key)
       _precondition(!found, "Dictionary literal contains duplicate keys")
-      unsafe native._insert(at: bucket, key: key, value: value)
+      native._insert(at: bucket, key: key, value: value)
     }
     self.init(_native: native)
   }
@@ -904,11 +904,11 @@ extension Dictionary {
     }
     @inline(__always)
     _modify {
-      let (bucket, found) = unsafe _variant.mutatingFind(key)
+      let (bucket, found) = _variant.mutatingFind(key)
       let native = _variant.asNative
       if !found {
         let value = defaultValue()
-        unsafe native._insert(at: bucket, key: key, value: value)
+        native._insert(at: bucket, key: key, value: value)
       }
       let address = unsafe native._values + bucket.offset
       defer { _fixLifetime(self) }
@@ -1458,7 +1458,7 @@ extension Dictionary {
       }
       _modify {
         let native = _variant.ensureUniqueNative()
-        let bucket = unsafe native.validatedBucket(for: position)
+        let bucket = native.validatedBucket(for: position)
         let address = unsafe native._values + bucket.offset
         defer { _fixLifetime(self) }
         yield unsafe &address.pointee
@@ -1491,9 +1491,9 @@ extension Dictionary {
 #endif
       let isUnique = _variant.isUniquelyReferenced()
       let native = _variant.asNative
-      let a = unsafe native.validatedBucket(for: i)
-      let b = unsafe native.validatedBucket(for: j)
-      unsafe _variant.asNative.swapValuesAt(a, b, isUnique: isUnique)
+      let a = native.validatedBucket(for: i)
+      let b = native.validatedBucket(for: j)
+      _variant.asNative.swapValuesAt(a, b, isUnique: isUnique)
     }
   }
 }
diff --git a/stdlib/public/core/DictionaryBridging.swift b/stdlib/public/core/DictionaryBridging.swift
index 3077635c47674..e1c080b00f423 100644
--- a/stdlib/public/core/DictionaryBridging.swift
+++ b/stdlib/public/core/DictionaryBridging.swift
@@ -98,12 +98,12 @@ final internal class _SwiftDictionaryNSEnumerator<Key: Hashable, Value>
 
   @objc
   internal func nextObject() -> AnyObject? {
-    if unsafe nextBucket == endBucket {
+    if nextBucket == endBucket {
       return nil
     }
-    let bucket = unsafe nextBucket
+    let bucket = nextBucket
     unsafe nextBucket = base.hashTable.occupiedBucket(after: nextBucket)
-    return unsafe self.bridgedKey(at: bucket)
+    return self.bridgedKey(at: bucket)
   }
 
   @objc(countByEnumeratingWithState:objects:count:)
@@ -119,7 +119,7 @@ final internal class _SwiftDictionaryNSEnumerator<Key: Hashable, Value>
       unsafe theState.mutationsPtr = _fastEnumerationStorageMutationsPtr
     }
 
-    if unsafe nextBucket == endBucket {
+    if nextBucket == endBucket {
       unsafe state.pointee = theState
       return 0
     }
@@ -411,11 +411,11 @@ final internal class _SwiftDeferredNSDictionary<Key: Hashable, Value>
     // Only need to bridge once, so we can hoist it out of the loop.
     let bridgedKeys = unsafe bridgeKeys()
     for i in 0..<count {
-      if unsafe bucket == endBucket { break }
+      if bucket == endBucket { break }
 
       unsafe unmanagedObjects[i] = unsafe _key(at: bucket, bridgedKeys: bridgedKeys)
       stored += 1
-      unsafe bucket = unsafe hashTable.occupiedBucket(after: bucket)
+      bucket = unsafe hashTable.occupiedBucket(after: bucket)
     }
     unsafe theState.extra.0 = CUnsignedLong(bucket.offset)
     unsafe state.pointee = theState
diff --git a/stdlib/public/core/DictionaryBuilder.swift b/stdlib/public/core/DictionaryBuilder.swift
index c3235090d17d3..52685b7071482 100644
--- a/stdlib/public/core/DictionaryBuilder.swift
+++ b/stdlib/public/core/DictionaryBuilder.swift
@@ -136,11 +136,11 @@ extension _NativeDictionary {
     // Each iteration of the loop below processes an unprocessed element, and/or
     // reduces the size of the unprocessed region, while ensuring the above
     // invariants.
-    var bucket = unsafe _HashTable.Bucket(offset: initializedCount - 1)
-    while unsafe bucket.offset >= 0 {
+    var bucket = _HashTable.Bucket(offset: initializedCount - 1)
+    while bucket.offset >= 0 {
       if unsafe hashTable._isOccupied(bucket) {
         // We've moved an element here in a previous iteration.
-        unsafe bucket.offset -= 1
+        bucket.offset -= 1
         continue
       }
       // Find the target bucket for this entry and mark it as in use.
@@ -148,35 +148,35 @@ extension _NativeDictionary {
       if _isDebugAssertConfiguration() || allowingDuplicates {
         let (b, found) = unsafe find(_keys[bucket.offset])
         if found {
-          unsafe _internalInvariant(b != bucket)
+          _internalInvariant(b != bucket)
           _precondition(allowingDuplicates, "Duplicate keys found")
           // Discard duplicate entry.
           unsafe uncheckedDestroy(at: bucket)
           unsafe _storage._count -= 1
-          unsafe bucket.offset -= 1
+          bucket.offset -= 1
           continue
         }
         unsafe hashTable.insert(b)
-        unsafe target = unsafe b
+        target = b
       } else {
         let hashValue = unsafe self.hashValue(for: _keys[bucket.offset])
-        unsafe target = unsafe hashTable.insertNew(hashValue: hashValue)
+        target = unsafe hashTable.insertNew(hashValue: hashValue)
       }
 
-      if unsafe target > bucket {
+      if target > bucket {
         // The target is outside the unprocessed region.  We can simply move the
         // entry, leaving behind an uninitialized bucket.
-        unsafe moveEntry(from: bucket, to: target)
+        moveEntry(from: bucket, to: target)
         // Restore invariants by lowering the region boundary.
-        unsafe bucket.offset -= 1
-      } else if unsafe target == bucket {
+        bucket.offset -= 1
+      } else if target == bucket {
         // Already in place.
-        unsafe bucket.offset -= 1
+        bucket.offset -= 1
       } else {
         // The target bucket is also in the unprocessed region. Swap the current
         // item into place, then try again with the swapped-in value, so that we
         // don't lose it.
-        unsafe swapEntry(target, with: bucket)
+        swapEntry(target, with: bucket)
       }
     }
     // When there are no more unprocessed entries, we're left with a valid
diff --git a/stdlib/public/core/DictionaryStorage.swift b/stdlib/public/core/DictionaryStorage.swift
index 2de249834a415..4f9a3c70644b7 100644
--- a/stdlib/public/core/DictionaryStorage.swift
+++ b/stdlib/public/core/DictionaryStorage.swift
@@ -247,11 +247,11 @@ extension __RawDictionaryStorage {
       var bucket = unsafe hashTable.idealBucket(forHashValue: hashValue)
       while unsafe hashTable._isOccupied(bucket) {
         if unsafe uncheckedKey(at: bucket) == key {
-          return unsafe (bucket, true)
+          return (bucket, true)
         }
-        unsafe bucket = unsafe hashTable.bucket(wrappedAfter: bucket)
+        bucket = unsafe hashTable.bucket(wrappedAfter: bucket)
       }
-      return unsafe (bucket, false)
+      return (bucket, false)
   }
 }
 
@@ -358,13 +358,13 @@ final internal class _DictionaryStorage<Key: Hashable, Value>
       "Invalid fast enumeration state")
     var stored = 0
     for i in 0..<count {
-      if unsafe bucket == endBucket { break }
+      if bucket == endBucket { break }
 
       let key = unsafe _keys[bucket.offset]
       unsafe unmanagedObjects[i] = _bridgeAnythingToObjectiveC(key)
 
       stored += 1
-      unsafe bucket = unsafe hashTable.occupiedBucket(after: bucket)
+      bucket = unsafe hashTable.occupiedBucket(after: bucket)
     }
     unsafe theState.extra.0 = CUnsignedLong(bucket.offset)
     unsafe state.pointee = theState
@@ -479,7 +479,7 @@ extension _DictionaryStorage {
       bucketCount._builtinWordValue, Value.self)
 
     let metadataAddr = unsafe Builtin.projectTailElems(storage, _HashTable.Word.self)
-    let keysAddr = unsafe Builtin.getTailAddr_Word(
+    let keysAddr = Builtin.getTailAddr_Word(
       metadataAddr, wordCount._builtinWordValue, _HashTable.Word.self,
       Key.self)
     let valuesAddr = Builtin.getTailAddr_Word(
diff --git a/stdlib/public/core/DictionaryVariant.swift b/stdlib/public/core/DictionaryVariant.swift
index 05fce1e55354e..199f404237fb5 100644
--- a/stdlib/public/core/DictionaryVariant.swift
+++ b/stdlib/public/core/DictionaryVariant.swift
@@ -324,7 +324,7 @@ extension Dictionary._Variant {
         cocoa, capacity: cocoa.count + 1)
       let result = native.mutatingFind(key, isUnique: true)
       self = .init(native: native)
-      return unsafe result
+      return result
     }
 #endif
     let isUnique = isUniquelyReferenced()
@@ -390,7 +390,7 @@ extension Dictionary._Variant {
     // FIXME(performance): fuse data migration and element deletion into one
     // operation.
     let native = ensureUniqueNative()
-    let bucket = unsafe native.validatedBucket(for: index)
+    let bucket = native.validatedBucket(for: index)
     return unsafe asNative.uncheckedRemove(at: bucket, isUnique: true)
   }
 
diff --git a/stdlib/public/core/Diffing.swift b/stdlib/public/core/Diffing.swift
index 3fd9f136530f2..cd2a53a69cb75 100644
--- a/stdlib/public/core/Diffing.swift
+++ b/stdlib/public/core/Diffing.swift
@@ -148,7 +148,7 @@ extension BidirectionalCollection {
     by areEquivalent: (C.Element, Element) -> Bool
   ) -> CollectionDifference<Element>
   where C.Element == Self.Element {
-    return _myers(from: other, to: self, using: areEquivalent)
+    _linearSpaceMyers(from: other, to: self, using: areEquivalent)
   }
 }
 
@@ -173,194 +173,458 @@ extension BidirectionalCollection where Element: Equatable {
   public func difference<C: BidirectionalCollection>(
     from other: C
   ) -> CollectionDifference<Element> where C.Element == Self.Element {
-    return difference(from: other, by: ==)
+    difference(from: other, by: ==)
   }
 }
 
 // MARK: Internal implementation
 
-// _V is a rudimentary type made to represent the rows of the triangular matrix
-// type used by the Myer's algorithm.
-//
-// This type is basically an array that only supports indexes in the set
-// `stride(from: -d, through: d, by: 2)` where `d` is the depth of this row in
-// the matrix `d` is always known at allocation-time, and is used to preallocate
-// the structure.
-private struct _V {
-
-  private var a: [Int]
+/// Storage for the two "k-vectors" used by the Myers diffing
+/// algorithm, using a single allocation.
+///
+/// The two k-vectors are stored one after the other in this type's
+/// buffer. For a given size `s`, each k-vector provides space for
+/// offsets in the range `-s...s`, using this layout for the buffer
+/// and offsets when `s == 2`:
+///
+/// ```
+/// ┌─────────────────────────────────────────────────────────────┐
+/// │             0    1    2    3    4    5    6    7    8    9  │
+/// │          ┌────┬────┬────┬────┬────┬────┬────┬────┬────┬────┐│
+/// │ buffer:  │ .. │ .. │ .. │ .. │ .. │ .. │ .. │ .. │ .. │ .. ││
+/// │          └────┴────┴────┴────┴────┴────┴────┴────┴────┴────┘│
+/// |                       ^                        ^            |
+/// |                  forwardOffset           backwardOffset     |
+/// │          ┌────┬────┬────┬────┬────┐                         │
+/// │ forward: │ -2 │ -1 │  0 │  1 │  2 │                         │
+/// │          └────┴────┴────┴────┴────┘                         │
+/// │                                   ┌────┬────┬────┬────┬────┐│
+/// │ backward:                         │ -2 │ -1 │  0 │  1 │  2 ││
+/// │                                   └────┴────┴────┴────┴────┘│
+/// └─────────────────────────────────────────────────────────────┘
+/// ```
+@safe fileprivate struct DoubleKVector: ~Copyable {
+  let buffer: UnsafeMutableBufferPointer<Int>
+  let forwardOffset: Int
+  let backwardOffset: Int
 #if INTERNAL_CHECKS_ENABLED
-  private let isOdd: Bool
+  private let range: Int
 #endif
 
-  init(maxIndex largest: Int) {
+  /// Creates a new double k-vector.
+  ///
+  /// The size of the resulting array is `((2 * size) + 1) * 2`,
+  /// enough space to store two k-vectors ranging from `-size`
+  /// through `size`.
+  init(size: Int) {
+    let range = size * 2 + 1
+    unsafe self.buffer = .allocate(capacity: range * 2)
+    self.forwardOffset = size
+    self.backwardOffset = range + size
+    unsafe buffer.initialize(repeating: 0)
 #if INTERNAL_CHECKS_ENABLED
-    _internalInvariant(largest >= 0)
-    isOdd = largest % 2 == 1
+    self.range = range
 #endif
-    a = [Int](repeating: 0, count: largest + 1)
   }
 
-  // The way negative indexes are implemented is by interleaving them in the empty slots between the valid positive indexes
-  @inline(__always) private static func transform(_ index: Int) -> Int {
-    // -3, -1, 1, 3 -> 3, 1, 0, 2 -> 0...3
-    // -2, 0, 2 -> 2, 0, 1 -> 0...2
-    return (index <= 0 ? -index : index &- 1)
+  deinit {
+    unsafe buffer.deallocate()
+  }
+  
+  @inline(__always) fileprivate func forwardTransform(_ index: Int) -> Int {
+    forwardOffset &+ index
   }
 
-  subscript(index: Int) -> Int {
+  @inline(__always) fileprivate func backwardTransform(_ index: Int) -> Int {
+    backwardOffset &+ index
+  }
+  
+  subscript(forward index: Int) -> Int {
     get {
 #if INTERNAL_CHECKS_ENABLED
-      _internalInvariant(isOdd == (index % 2 != 0))
+      precondition(((-range)...range).contains(index))
 #endif
-      return a[_V.transform(index)]
+      return unsafe buffer[forwardTransform(index)]
     }
     set(newValue) {
 #if INTERNAL_CHECKS_ENABLED
-      _internalInvariant(isOdd == (index % 2 != 0))
+      precondition(((-range)...range).contains(index))
 #endif
-      a[_V.transform(index)] = newValue
+      unsafe buffer[forwardTransform(index)] = newValue
+    }
+  }
+  
+  subscript(backward index: Int) -> Int {
+    get {
+#if INTERNAL_CHECKS_ENABLED
+      precondition(((-range)...range).contains(index))
+#endif
+      return unsafe buffer[backwardTransform(index)]
+    }
+    set(newValue) {
+#if INTERNAL_CHECKS_ENABLED
+      precondition(((-range)...range).contains(index))
+#endif
+      unsafe buffer[backwardTransform(index)] = newValue
     }
   }
 }
 
-@available(SwiftStdlib 5.1, *)
-private func _myers<C,D>(
-  from old: C, to new: D,
-  using cmp: (C.Element, D.Element) -> Bool
-) -> CollectionDifference<C.Element>
-  where
-    C: BidirectionalCollection,
-    D: BidirectionalCollection,
-    C.Element == D.Element
-{
+/// A two-dimensional region of a Myers diff algorithm edit graph.
+fileprivate struct EditGraphRect: Equatable {
+  var left: Int
+  var top: Int
+  var right: Int
+  var bottom: Int
+  
+  var width: Int {
+    right &- left
+  }
 
-  // Core implementation of the algorithm described at http://www.xmailserver.org/diff2.pdf
-  // Variable names match those used in the paper as closely as possible
-  func _descent(from a: UnsafeBufferPointer<C.Element>, to b: UnsafeBufferPointer<D.Element>) -> [_V] {
-    let n = a.count
-    let m = b.count
-    let max = n + m
+  var height: Int {
+    bottom &- top
+  }
 
-    var result = [_V]()
-    var v = _V(maxIndex: 1)
-    v[1] = 0
+  var size: Int {
+    width &+ height
+  }
 
-    var x = 0
-    var y = 0
-    iterator: for d in 0...max {
-      let prev_v = v
-      result.append(v)
-      v = _V(maxIndex: d)
+  var delta: Int {
+    width &- height
+  }
+  
+  var isEven: Bool {
+    delta.isMultiple(of: 2)
+  }
+  
+  var isOdd: Bool {
+    !delta.isMultiple(of: 2)
+  }
+  
+  var max: Int {
+    (size &+ 1) / 2
+  }
+  
+  /// Shrinks this box so that its bottom right corner is the top left corner of
+  /// the given box.
+  func cropped(toTopLeftOf limit: EditGraphRect) -> EditGraphRect {
+    .init(left: left, top: top, right: limit.left, bottom: limit.top)
+  }
+  
+  /// Shrinks this box so that its top left corner is the bottom right corner of
+  /// the given box.
+  func cropped(toBottomRightOf limit: EditGraphRect) -> EditGraphRect {
+    .init(left: limit.right, top: limit.bottom, right: right, bottom: bottom)
+  }
 
-      // The code in this loop is _very_ hot—the loop bounds increases in terms
-      // of the iterator of the outer loop!
-      for k in stride(from: -d, through: d, by: 2) {
-        if k == -d {
-          x = prev_v[k &+ 1]
-        } else {
-          let km = prev_v[k &- 1]
+  /// Shrinks this box from both top and bottom by following diagonal paths
+  /// (equal corresponding elements) in the two collections that are the target
+  /// of diffing.
+  func shrunk<T>(
+    old: UnsafeBufferPointer<T>,
+    new: UnsafeBufferPointer<T>,
+    cmp: (T, T) -> Bool
+  ) -> EditGraphRect {
+    var r = self
+    while r.left < r.right, r.top < r.bottom,
+          unsafe cmp(old[r.left], new[r.top])
+    {
+      r.left &+= 1
+      r.top &+= 1
+    }
+    while r.right > r.left, r.bottom > r.top,
+          unsafe cmp(old[r.right - 1], new[r.bottom - 1])
+    {
+      r.right &-= 1
+      r.bottom &-= 1
+    }
+    return r
+  }
+}
 
-          if k != d {
-            let kp = prev_v[k &+ 1]
-            if km < kp {
-              x = kp
-            } else {
-              x = km &+ 1
-            }
-          } else {
-            x = km &+ 1
-          }
+fileprivate struct LinearMyers: ~Copyable {
+  var kVector: DoubleKVector
+  
+  /// Implements a refinement of the Myers diffing algorithm that uses
+  /// linear space for storing the "k vectors" during an iterative divide-
+  /// and-conquer search.
+  @available(SwiftStdlib 5.1, *)
+  mutating func findDifferences<T>(
+    in initial: EditGraphRect,
+    old: UnsafeBufferPointer<T>,
+    new: UnsafeBufferPointer<T>,
+    cmp: (T, T) -> Bool
+  ) -> [CollectionDifference<T>.Change] {
+    var result: [CollectionDifference<T>.Change] = []
+    var stack: [EditGraphRect] = []
+    var current = initial
+    
+    while true {
+      let (edit, snakeBox) = unsafe middleSnake(
+        in: current, old: old, new: new, cmp: cmp)
+      
+      // Append edit if exists
+      if let edit {
+        result.append(edit)
+      }
+      
+      guard let snakeBox else {
+        // Didn't find a new middle snake, so we'll look at the next area on the
+        // stack next (the right side of the last snake)
+        guard let next = stack.popLast() else {
+          // Stack is empty -- all done with diff!
+          return result
         }
-        y = x &- k
-
-        while x < n && y < m {
-          if unsafe !cmp(a[x], b[y]) {
-            break;
-          }
-          x &+= 1
-          y &+= 1
+        current = next
+        continue
+      }
+      
+      let headBox = unsafe current.cropped(toTopLeftOf: snakeBox)
+        .shrunk(old: old, new: new, cmp: cmp)
+      let tailBox = unsafe current.cropped(toBottomRightOf: snakeBox)
+        .shrunk(old: old, new: new, cmp: cmp)
+      
+      // Process the left side of the snake next
+      current = headBox
+      // Save the right side of the snake for later
+      stack.append(tailBox)
+    }
+    fatalError("Unreachable")
+  }
+  
+  @available(SwiftStdlib 5.1, *)
+  fileprivate mutating func middleSnake<T>(
+    in box: EditGraphRect,
+    old: UnsafeBufferPointer<T>, new: UnsafeBufferPointer<T>,
+    cmp: (T, T) -> Bool
+  ) -> (CollectionDifference<T>.Change?, EditGraphRect?) {
+    guard box.size > 1 else {
+      // One rightward or downward move represents a removal or insertion.
+      if box.size == 0 {
+        return (nil, nil)
+      } else if box.width == 1 {
+        return unsafe (.remove(offset: box.left, element: old[box.left], associatedWith: nil), nil)
+      } else {
+        return unsafe (.insert(offset: box.top, element: new[box.top], associatedWith: nil), nil)
+      }
+    }
+    
+    // Reset for depth == 0
+    kVector[forward: 1] = box.left
+    kVector[backward: 1] = box.bottom
+    
+    for depth in 0...box.max {
+      if box.isOdd {
+        if let result = unsafe forwardSearch(
+          in: box, depth: depth, old: old, new: new, cmp: cmp)
+        {
+          return result
         }
-
-        v[k] = x
-
-        if x >= n && y >= m {
-          break iterator
+        _ = unsafe backwardSearch(in: box, depth: depth, old: old, new: new, cmp: cmp)
+      } else {
+        _ = unsafe forwardSearch(in: box, depth: depth, old: old, new: new, cmp: cmp)
+        if let result = unsafe backwardSearch(
+          in: box, depth: depth, old: old, new: new, cmp: cmp)
+        {
+          return result
         }
       }
-      if x >= n && y >= m {
-        break
+    }
+    fatalError("Unreachable")
+  }
+  
+  @available(SwiftStdlib 5.1, *)
+  fileprivate mutating func forwardSearch<T>(
+    in box: EditGraphRect,
+    depth: Int,
+    old: UnsafeBufferPointer<T>,
+    new: UnsafeBufferPointer<T>,
+    cmp: (T, T) -> Bool
+  ) -> (CollectionDifference<T>.Change, EditGraphRect)? {
+    for k in stride(from: depth, through: -depth, by: -2) {
+      // The furthest right and down we search
+      var newRight, newBottom: Int
+      // The top/left of the candidate middle snake
+      let newLeft, newTop: Int
+      
+      // Information about the selected edit, if used
+      let isInsertion: Bool
+      let editIndex: Int
+            
+      // Choose whether this is an insertion or a deletion, then set up
+      // bounds of candidate middle snake.
+      if k == -depth ||
+          (k != depth && kVector[forward: k - 1] < kVector[forward: k + 1])
+      {
+        newRight = kVector[forward: k + 1]
+        newLeft = newRight
+        newBottom = box.top + (newRight - box.left) - k
+        
+        isInsertion = true
+        editIndex = newBottom - 1
+      } else {
+        newLeft = kVector[forward: k - 1]
+        newRight = newLeft + 1
+        newBottom = box.top + (newRight - box.left) - k
+        
+        isInsertion = false
+        editIndex = newLeft
+      }
+      newTop = if depth == 0 || newRight != newLeft {
+        newBottom
+      } else {
+        newBottom - 1
+      }
+      
+      // Follow any diagonal after the movement
+      while newRight < box.right && newBottom < box.bottom,
+            unsafe cmp(old[newRight], new[newBottom])
+      {
+        newRight &+= 1
+        newBottom &+= 1
+      }
+      kVector[forward: k] = newRight
+      
+      // Only check for overlap in _odd-sized_ boxes when moving _forward_
+      guard box.isOdd else { continue }
+      
+      // If `c` is in bounds and there's an overlap, return the identified edit
+      // and the eliminated box.
+      let c = k - box.delta
+      if (c >= -(depth - 1) && c <= depth - 1) && newBottom >= kVector[backward: c] {
+        let edit: CollectionDifference<T>.Change = if isInsertion {
+          unsafe .insert(offset: editIndex, element: new[editIndex], associatedWith: nil)
+        } else {
+          unsafe .remove(offset: editIndex, element: old[editIndex], associatedWith: nil)
+        }
+        return (
+          edit,
+          EditGraphRect(left: newLeft, top: newTop, right: newRight, bottom: newBottom))
       }
     }
-
-    _internalInvariant(x >= n && y >= m)
-
-    return result
+    return nil
   }
+    
+  @available(SwiftStdlib 5.1, *)
+  fileprivate mutating func backwardSearch<T>(
+    in box: EditGraphRect,
+    depth: Int,
+    old: UnsafeBufferPointer<T>,
+    new: UnsafeBufferPointer<T>,
+    cmp: (T, T) -> Bool
+  ) -> (CollectionDifference<T>.Change, EditGraphRect)? {
+    for c in stride(from: depth, through: -depth, by: -2) {
+      let k = c + box.delta
+      // The furthest up and left we search
+      var newLeft, newTop: Int
+      // The bottom/right of the candidate middle snake
+      let newRight, newBottom: Int
+      
+      // Information about the selected edit, if used
+      let isInsertion: Bool
+      let editIndex: Int
+      
+      // Choose whether this is an insertion or a deletion, then set up
+      // bounds of candidate middle snake.
+      if c == -depth ||
+          (c != depth && kVector[backward: c - 1] > kVector[backward: c + 1])
+      {
+        newTop = kVector[backward: c + 1]
+        newBottom = newTop
+        newLeft = box.left + (newTop - box.top) + k
+        
+        isInsertion = false
+        editIndex = newLeft
+      } else {
+        newBottom = kVector[backward: c - 1]
+        newTop = newBottom - 1
+        newLeft = box.left + (newTop - box.top) + k
 
-  // Backtrack through the trace generated by the Myers descent to produce the changes that make up the diff
-  func _formChanges(
-    from a: UnsafeBufferPointer<C.Element>,
-    to b: UnsafeBufferPointer<C.Element>,
-    using trace: [_V]
-  ) -> [CollectionDifference<C.Element>.Change] {
-    var changes = [CollectionDifference<C.Element>.Change]()
-    changes.reserveCapacity(trace.count)
-
-    var x = a.count
-    var y = b.count
-    for d in stride(from: trace.count &- 1, to: 0, by: -1) {
-      let v = trace[d]
-      let k = x &- y
-      let prev_k = (k == -d || (k != d && v[k &- 1] < v[k &+ 1])) ? k &+ 1 : k &- 1
-      let prev_x = v[prev_k]
-      let prev_y = prev_x &- prev_k
-
-      while x > prev_x && y > prev_y {
-        // No change at this position.
-        x &-= 1
-        y &-= 1
+        isInsertion = true
+        editIndex = newTop
       }
-
-      _internalInvariant((x == prev_x && y > prev_y) || (y == prev_y && x > prev_x))
-      if y != prev_y {
-        unsafe changes.append(.insert(offset: prev_y, element: b[prev_y], associatedWith: nil))
+      newRight = if depth == 0 || newTop != newBottom {
+        newLeft
       } else {
-        unsafe changes.append(.remove(offset: prev_x, element: a[prev_x], associatedWith: nil))
+        newLeft + 1
+      }
+      
+      // Follow any diagonal after the movement
+      while newLeft > box.left && newTop > box.top,
+            unsafe cmp(old[newLeft - 1], new[newTop - 1])
+      {
+        newLeft &-= 1
+        newTop &-= 1
+      }
+      kVector[backward: c] = newTop
+      
+      // Only check for overlap in _even-sized_ boxes when moving _backward_
+      guard box.isEven else { continue }
+      
+      // If `k` is in bounds and there's an overlap, return the identified edit
+      // and the eliminated box.
+      if (k >= -depth && k <= depth) && newLeft <= kVector[forward: k] {
+        let edit: CollectionDifference<T>.Change = if isInsertion {
+          unsafe .insert(offset: editIndex, element: new[editIndex], associatedWith: nil)
+        } else {
+          unsafe .remove(offset: editIndex, element: old[editIndex], associatedWith: nil)
+        }
+        return (
+          edit,
+          EditGraphRect(left: newLeft, top: newTop, right: newRight, bottom: newBottom))
       }
-
-      x = prev_x
-      y = prev_y
     }
+    return nil
+  }
+}
 
-    return changes
+extension LinearMyers {
+  fileprivate init?(
+    initialSize size: Int
+  ) {
+    guard size >= 0 else { return nil }
+    self.kVector = DoubleKVector(size: size)
   }
+}
 
+@available(SwiftStdlib 5.1, *)
+func _linearSpaceMyers<C,D>(
+  from old: C, to new: D,
+  using cmp: (C.Element, D.Element) -> Bool
+) -> CollectionDifference<C.Element>
+  where
+    C: BidirectionalCollection,
+    D: BidirectionalCollection,
+    C.Element == D.Element
+{
   /* Splatting the collections into contiguous storage has two advantages:
    *
    *   1) Subscript access is much faster
    *   2) Subscript index becomes Int, matching the iterator types in the algorithm
    *
-   * Combined, these effects dramatically improves performance when
+   * Combined, these effects dramatically improve performance when
    * collections differ significantly, without unduly degrading runtime when
    * the parameters are very similar.
-   *
-   * In terms of memory use, the linear cost of creating a ContiguousArray (when
-   * necessary) is significantly less than the worst-case n² memory use of the
-   * descent algorithm.
    */
   func _withContiguousStorage<Col: Collection, R>(
     for values: Col,
-    _ body: (UnsafeBufferPointer<Col.Element>) throws -> R
-  ) rethrows -> R {
-    if let result = try values.withContiguousStorageIfAvailable(body) { return result }
+    _ body: (UnsafeBufferPointer<Col.Element>) -> R
+  ) -> R {
+    if let result = values.withContiguousStorageIfAvailable(body) { return result }
     let array = ContiguousArray(values)
-    return try unsafe array.withUnsafeBufferPointer(body)
+    return unsafe array.withUnsafeBufferPointer(body)
   }
 
   return unsafe _withContiguousStorage(for: old) { a in
     return unsafe _withContiguousStorage(for: new) { b in
-      return unsafe CollectionDifference(_formChanges(from: a, to: b, using:_descent(from: a, to: b)))!
+      let box = unsafe EditGraphRect(left: 0, top: 0, right: old.count, bottom: new.count)
+        .shrunk(old: a, new: b, cmp: cmp)
+      
+      guard var myers = LinearMyers(initialSize: box.size) else {
+        return CollectionDifference([])!
+      }
+      let diffs = unsafe myers.findDifferences(in: box, old: a, new: b, cmp: cmp)
+      return CollectionDifference(diffs)!
     }
   }
 }
diff --git a/stdlib/public/core/DiscontiguousSlice.swift b/stdlib/public/core/DiscontiguousSlice.swift
index e901978d041e7..c8fa9accaec9e 100644
--- a/stdlib/public/core/DiscontiguousSlice.swift
+++ b/stdlib/public/core/DiscontiguousSlice.swift
@@ -350,7 +350,7 @@ extension DiscontiguousSlice where Base: MutableCollection {
   /// past the last element of a collection, so it doesn't correspond with an
   /// element.
   ///
-  /// - Parameter position: The position of the element to access. `position`
+  /// - Parameter i: The position of the element to access. `i`
   ///   must be a valid index of the collection that is not equal to the
   ///   `endIndex` property.
   ///
diff --git a/stdlib/public/core/DropWhile.swift b/stdlib/public/core/DropWhile.swift
index e7ad8a35d4dca..4d07b0471ceb3 100644
--- a/stdlib/public/core/DropWhile.swift
+++ b/stdlib/public/core/DropWhile.swift
@@ -21,7 +21,7 @@ public struct LazyDropWhileSequence<Base: Sequence> {
   @usableFromInline // lazy-performance
   internal let _predicate: (Element) -> Bool
 
-  /// Create an instance with elements `transform(x)` for each element
+  /// Create an instance with elements `predicate(x)` for each element
   /// `x` of base.
   @inlinable // lazy-performance
   internal init(_base: Base, predicate: @escaping (Element) -> Bool) {
diff --git a/stdlib/public/core/Duration.swift b/stdlib/public/core/Duration.swift
index 5b3b9da5bae0e..91430592945d2 100644
--- a/stdlib/public/core/Duration.swift
+++ b/stdlib/public/core/Duration.swift
@@ -31,7 +31,7 @@
 /// temporal measurement component; specifically leap seconds should be 
 /// represented as an additional accessor since that is specific only to certain
 /// clock implementations.
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @frozen
 public struct Duration: Sendable {
   /// The low 64 bits of a 128-bit signed integer value counting attoseconds.
@@ -86,13 +86,13 @@ public struct Duration: Sendable {
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Duration {
   /// The composite components of the `Duration`.
   ///
   /// This is intended for facilitating conversions to existing time types. The
   /// attoseconds value will not exceed 1e18 or be lower than -1e18.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public var components: (seconds: Int64, attoseconds: Int64) {
     let (seconds, attoseconds) = _attoseconds.dividedBy1e18()
     return (Int64(seconds), Int64(attoseconds))
@@ -129,7 +129,7 @@ extension Duration {
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Duration {
   /// Construct a `Duration` given a number of seconds represented as a 
   /// `BinaryInteger`.
@@ -137,7 +137,7 @@ extension Duration {
   ///       let d: Duration = .seconds(77)
   ///
   /// - Returns: A `Duration` representing a given number of seconds.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   @inlinable
   public static func seconds<T: BinaryInteger>(_ seconds: T) -> Duration {
     guard let high = Int64(exactly: seconds >> 64) else { fatalError() }
@@ -170,7 +170,7 @@ extension Duration {
   ///       let d: Duration = .seconds(22.93)
   ///
   /// - Returns: A `Duration` representing a given number of seconds.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func seconds(_ seconds: Double) -> Duration {
     Duration(seconds, scale: 1_000_000_000_000_000_000)
   }
@@ -181,7 +181,7 @@ extension Duration {
   ///       let d: Duration = .milliseconds(645)
   ///
   /// - Returns: A `Duration` representing a given number of milliseconds.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   @inlinable
   public static func milliseconds<T: BinaryInteger>(
     _ milliseconds: T
@@ -199,7 +199,7 @@ extension Duration {
   ///       let d: Duration = .milliseconds(88.3)
   ///
   /// - Returns: A `Duration` representing a given number of milliseconds.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func milliseconds(_ milliseconds: Double) -> Duration {
     Duration(milliseconds, scale: 1_000_000_000_000_000)
   }
@@ -210,7 +210,7 @@ extension Duration {
   ///       let d: Duration = .microseconds(12)
   ///
   /// - Returns: A `Duration` representing a given number of microseconds.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   @inlinable
   public static func microseconds<T: BinaryInteger>(
     _ microseconds: T
@@ -228,7 +228,7 @@ extension Duration {
   ///       let d: Duration = .microseconds(382.9)
   ///
   /// - Returns: A `Duration` representing a given number of microseconds.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func microseconds(_ microseconds: Double) -> Duration {
     Duration(microseconds, scale: 1_000_000_000_000)
   }
@@ -239,7 +239,7 @@ extension Duration {
   ///       let d: Duration = .nanoseconds(1929)
   ///
   /// - Returns: A `Duration` representing a given number of nanoseconds.
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   @inlinable
   public static func nanoseconds<T: BinaryInteger>(
     _ nanoseconds: T
@@ -250,12 +250,23 @@ extension Duration {
     let highScaled = high * 1_000_000_000
     return Duration(_high: highScaled + Int64(lowScaled.high), low: lowScaled.low)
   }
+  
+  /// Construct a `Duration` given a number of nanoseconds as a
+  /// `Double` by converting the value into the closest attosecond scale value.
+  ///
+  ///       let d: Duration = .nanoseconds(382.9)
+  ///
+  /// - Returns: A `Duration` representing a given number of nanoseconds.
+  @available(SwiftStdlib 6.2, *)
+  public static func nanoseconds(_ nanoseconds: Double) -> Duration {
+    Duration(nanoseconds, scale: 1_000_000_000)
+  }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_unavailableInEmbedded
 extension Duration: Codable {
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public init(from decoder: Decoder) throws {
     var container = try decoder.unkeyedContainer()
     let high = try container.decode(Int64.self)
@@ -263,7 +274,7 @@ extension Duration: Codable {
     self.init(_high: high, low: low)
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public func encode(to encoder: Encoder) throws {
     var container = encoder.unkeyedContainer()
     try container.encode(_high)
@@ -271,112 +282,112 @@ extension Duration: Codable {
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Duration: Hashable {
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public func hash(into hasher: inout Hasher) {
     hasher.combine(_attoseconds)
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Duration: Equatable {
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func == (_ lhs: Duration, _ rhs: Duration) -> Bool {
     return lhs._attoseconds == rhs._attoseconds
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Duration: Comparable {
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func < (_ lhs: Duration, _ rhs: Duration) -> Bool {
     return lhs._attoseconds < rhs._attoseconds
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Duration: AdditiveArithmetic {
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static var zero: Duration { Duration(_attoseconds: 0) }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func + (_ lhs: Duration, _ rhs: Duration) -> Duration {
     return Duration(_attoseconds: lhs._attoseconds + rhs._attoseconds)
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func - (_ lhs: Duration, _ rhs: Duration) -> Duration {
     return Duration(_attoseconds: lhs._attoseconds - rhs._attoseconds)
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func += (_ lhs: inout Duration, _ rhs: Duration) {
     lhs = lhs + rhs
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func -= (_ lhs: inout Duration, _ rhs: Duration) {
     lhs = lhs - rhs
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Duration {
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func / (_ lhs: Duration, _ rhs: Double) -> Duration {
     return Duration(_attoseconds:
       _Int128(Double(lhs._attoseconds) / rhs))
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func /= (_ lhs: inout Duration, _ rhs: Double) {
     lhs = lhs / rhs
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func / <T: BinaryInteger>(
     _ lhs: Duration, _ rhs: T
   ) -> Duration {
     Duration(_attoseconds: lhs._attoseconds / _Int128(rhs))
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func /= <T: BinaryInteger>(_ lhs: inout Duration, _ rhs: T) {
     lhs = lhs / rhs
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func / (_ lhs: Duration, _ rhs: Duration) -> Double {
     Double(lhs._attoseconds) / Double(rhs._attoseconds)
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func * (_ lhs: Duration, _ rhs: Double) -> Duration {
     Duration(_attoseconds: _Int128(Double(lhs._attoseconds) * rhs))
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func * <T: BinaryInteger>(
     _ lhs: Duration, _ rhs: T
   ) -> Duration {
     Duration(_attoseconds: lhs._attoseconds * _Int128(rhs))
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func *= <T: BinaryInteger>(_ lhs: inout Duration, _ rhs: T) {
     lhs = lhs * rhs
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 @_unavailableInEmbedded
 extension Duration: CustomStringConvertible {
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public var description: String {
     return (Double(_attoseconds) / 1e18).description + " seconds"
   }
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension Duration: DurationProtocol { }
diff --git a/stdlib/public/core/DurationProtocol.swift b/stdlib/public/core/DurationProtocol.swift
index 4d538f4932f71..50a83c6308e29 100644
--- a/stdlib/public/core/DurationProtocol.swift
+++ b/stdlib/public/core/DurationProtocol.swift
@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 /// A type that defines a duration for a given `InstantProtocol` type.
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 public protocol DurationProtocol: Comparable, AdditiveArithmetic, Sendable {
   static func / (_ lhs: Self, _ rhs: Int) -> Self
   static func /= (_ lhs: inout Self, _ rhs: Int)
@@ -21,14 +21,14 @@ public protocol DurationProtocol: Comparable, AdditiveArithmetic, Sendable {
   static func / (_ lhs: Self, _ rhs: Self) -> Double
 }
 
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 extension DurationProtocol {
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func /= (_ lhs: inout Self, _ rhs: Int) {
     lhs = lhs / rhs
   }
 
-  @available(SwiftStdlib 5.7, *)
+  @available(StdlibDeploymentTarget 5.7, *)
   public static func *= (_ lhs: inout Self, _ rhs: Int) {
     lhs = lhs * rhs
   }
diff --git a/stdlib/public/core/EmbeddedRuntime.swift b/stdlib/public/core/EmbeddedRuntime.swift
index 84b2b52202930..d9804a8ab19c3 100644
--- a/stdlib/public/core/EmbeddedRuntime.swift
+++ b/stdlib/public/core/EmbeddedRuntime.swift
@@ -48,7 +48,7 @@ public struct ClassMetadata {
   └──────────────┴──────────────────────────────────────────────┘
 
   If the highest bit (doNotFreeBit) is set, the behavior of dropping the last reference (release operation where
-  refcount ends up being 0) is altered to avoid calling free() on the object (deinit is still run). This is crutial for
+  refcount ends up being 0) is altered to avoid calling free() on the object (deinit is still run). This is crucial for
   class instances that are promoted by the compiler from being heap-allocated to instead be located on the stack
   (see swift_initStackObject).
 
@@ -149,6 +149,13 @@ func alignedAlloc(size: Int, alignment: Int) -> UnsafeMutableRawPointer? {
   return unsafe r
 }
 
+@_cdecl("swift_coroFrameAlloc")
+public func swift_coroFrameAlloc(_ size: Int, _ type: UInt) -> UnsafeMutableRawPointer? {
+  return unsafe alignedAlloc(
+    size: size,
+    alignment: _swift_MinAllocationAlignment)
+}
+
 @_cdecl("swift_slowAlloc")
 public func swift_slowAlloc(_ size: Int, _ alignMask: Int) -> UnsafeMutableRawPointer? {
   let alignment: Int
@@ -178,6 +185,14 @@ func swift_allocObject(metadata: UnsafeMutablePointer<ClassMetadata>, requiredSi
   return unsafe object
 }
 
+@_cdecl("swift_deallocUninitializedObject")
+public func swift_deallocUninitializedObject(object: Builtin.RawPointer, allocatedSize: Int, allocatedAlignMask: Int) {
+  unsafe swift_deallocObject(
+    object: UnsafeMutablePointer<HeapObject>(object),
+    allocatedSize: allocatedSize,
+    allocatedAlignMask: allocatedAlignMask)
+}
+
 @_cdecl("swift_deallocObject")
 public func swift_deallocObject(object: Builtin.RawPointer, allocatedSize: Int, allocatedAlignMask: Int) {
   unsafe swift_deallocObject(object: UnsafeMutablePointer<HeapObject>(object), allocatedSize: allocatedSize, allocatedAlignMask: allocatedAlignMask)
@@ -236,6 +251,15 @@ func swift_initStackObject(metadata: UnsafeMutablePointer<ClassMetadata>, object
   return unsafe object
 }
 
+@unsafe
+public var _emptyBoxStorage: (Int, Int) = (/*isa*/0, /*refcount*/-1)
+
+@_cdecl("swift_allocEmptyBox")
+public func swift_allocEmptyBox() -> Builtin.RawPointer {
+  let box = unsafe Builtin.addressof(&_emptyBoxStorage)
+  swift_retain(object: box)
+  return box
+}
 
 
 /// Refcounting
@@ -307,6 +331,7 @@ func swift_isUniquelyReferenced_nonNull_native(object: UnsafeMutablePointer<Heap
 }
 
 @_cdecl("swift_retain")
+@discardableResult
 public func swift_retain(object: Builtin.RawPointer) -> Builtin.RawPointer {
   if !isValidPointerForNativeRetain(object: object) { return object }
 
@@ -335,6 +360,7 @@ func swift_retain_n_(object: UnsafeMutablePointer<HeapObject>, n: UInt32) -> Uns
 }
 
 @_cdecl("swift_bridgeObjectRetain")
+@discardableResult
 public func swift_bridgeObjectRetain(object: Builtin.RawPointer) -> Builtin.RawPointer {
   return swift_bridgeObjectRetain_n(object: object, n: 1)
 }
diff --git a/stdlib/public/core/Equatable.swift b/stdlib/public/core/Equatable.swift
index ef2779f5b34fb..ae634bc4e3cf0 100644
--- a/stdlib/public/core/Equatable.swift
+++ b/stdlib/public/core/Equatable.swift
@@ -271,7 +271,7 @@ public func === (lhs: AnyObject?, rhs: AnyObject?) -> Bool {
 #else
 @inlinable // trivial-implementation
 @safe
-public func ===<T: AnyObject, U: AnyObject>(lhs: T?, rhs: U?) -> Bool {
+public func === (lhs: AnyObject?, rhs: AnyObject?) -> Bool {
   switch (lhs, rhs) {
   case let (l?, r?):
     return Builtin.bridgeToRawPointer(l) == Builtin.bridgeToRawPointer(r)
@@ -293,14 +293,7 @@ public func ===<T: AnyObject, U: AnyObject>(lhs: T?, rhs: U?) -> Bool {
 /// - Parameters:
 ///   - lhs: A reference to compare.
 ///   - rhs: Another reference to compare.
-#if !$Embedded
 @inlinable // trivial-implementation
 public func !== (lhs: AnyObject?, rhs: AnyObject?) -> Bool {
   return !(lhs === rhs)
 }
-#else
-@inlinable // trivial-implementation
-public func !==<T: AnyObject, U: AnyObject>(lhs: T, rhs: U) -> Bool {
-  return !(lhs === rhs)
-}
-#endif
diff --git a/stdlib/public/core/ExistentialCollection.swift b/stdlib/public/core/ExistentialCollection.swift
index 13d412b8704b4..dc790a1234dcb 100644
--- a/stdlib/public/core/ExistentialCollection.swift
+++ b/stdlib/public/core/ExistentialCollection.swift
@@ -181,12 +181,14 @@ internal class _AnySequenceBox<Element> {
   @inlinable
   internal var _underestimatedCount: Int { _abstract() }
 
+#if !$Embedded
   @inlinable
   internal func _map<T>(
     _ transform: (Element) throws -> T
   ) throws -> [T] {
     _abstract()
   }
+#endif
 
   @inlinable
   internal func _filter(
@@ -534,12 +536,16 @@ internal final class _SequenceBox<S: Sequence>: _AnySequenceBox<S.Element> {
   internal override var _underestimatedCount: Int {
     return _base.underestimatedCount
   }
+
+#if !$Embedded
   @inlinable
   internal override func _map<T>(
     _ transform: (Element) throws -> T
   ) throws -> [T] {
     try _base.map(transform)
   }
+#endif
+
   @inlinable
   internal override func _filter(
     _ isIncluded: (Element) throws -> Bool
@@ -627,12 +633,14 @@ internal final class _CollectionBox<S: Collection>: _AnyCollectionBox<S.Element>
   internal override var _underestimatedCount: Int {
     return _base.underestimatedCount
   }
+#if !$Embedded
   @inlinable
   internal override func _map<T>(
     _ transform: (Element) throws -> T
   ) throws -> [T] {
     try _base.map(transform)
   }
+#endif
   @inlinable
   internal override func _filter(
     _ isIncluded: (Element) throws -> Bool
@@ -822,12 +830,14 @@ internal final class _BidirectionalCollectionBox<S: BidirectionalCollection>
   internal override var _underestimatedCount: Int {
     return _base.underestimatedCount
   }
+#if !$Embedded
   @inlinable
   internal override func _map<T>(
     _ transform: (Element) throws -> T
   ) throws -> [T] {
     try _base.map(transform)
   }
+#endif
   @inlinable
   internal override func _filter(
     _ isIncluded: (Element) throws -> Bool
@@ -1035,12 +1045,14 @@ internal final class _RandomAccessCollectionBox<S: RandomAccessCollection>
   internal override var _underestimatedCount: Int {
     return _base.underestimatedCount
   }
+#if !$Embedded
   @inlinable
   internal override func _map<T>(
     _ transform: (Element) throws -> T
   ) throws -> [T] {
     try _base.map(transform)
   }
+#endif
   @inlinable
   internal override func _filter(
     _ isIncluded: (Element) throws -> Bool
@@ -1322,6 +1334,7 @@ extension AnySequence {
     return _box._underestimatedCount
   }
 
+#if !$Embedded
   @inlinable
   @_alwaysEmitIntoClient
   public func map<T, E>(
@@ -1345,6 +1358,7 @@ extension AnySequence {
   ) throws -> [T] {
     try map(transform)
   }
+#endif
 
   @inlinable
   public __consuming func filter(
@@ -1426,6 +1440,7 @@ extension AnyCollection {
     return _box._underestimatedCount
   }
 
+#if !$Embedded
   @inlinable
   @_alwaysEmitIntoClient
   public func map<T, E>(
@@ -1449,6 +1464,7 @@ extension AnyCollection {
   ) throws -> [T] {
     try map(transform)
   }
+#endif
 
   @inlinable
   public __consuming func filter(
@@ -1536,6 +1552,7 @@ extension AnyBidirectionalCollection {
     return _box._underestimatedCount
   }
 
+#if !$Embedded
   @inlinable
   @_alwaysEmitIntoClient
   public func map<T, E>(
@@ -1559,6 +1576,7 @@ extension AnyBidirectionalCollection {
   ) throws -> [T] {
     try map(transform)
   }
+#endif
 
   @inlinable
   public __consuming func filter(
@@ -1648,6 +1666,7 @@ extension AnyRandomAccessCollection {
     return _box._underestimatedCount
   }
 
+#if !$Embedded
   @inlinable
   @_alwaysEmitIntoClient
   public func map<T, E>(
@@ -1671,6 +1690,7 @@ extension AnyRandomAccessCollection {
   ) throws -> [T] {
     try map(transform)
   }
+#endif
 
   @inlinable
   public __consuming func filter(
diff --git a/stdlib/public/core/FloatingPointTypes.swift.gyb b/stdlib/public/core/FloatingPointTypes.swift.gyb
index 5f50ea00d5c72..5a1892ddd663b 100644
--- a/stdlib/public/core/FloatingPointTypes.swift.gyb
+++ b/stdlib/public/core/FloatingPointTypes.swift.gyb
@@ -41,25 +41,27 @@ def Availability(bits):
 
 if Self == 'Float16':
     SelfDocComment = '''\
-/// A half-precision (16b), floating-point value type.
+/// A half-precision (16-bit), floating-point value type.
 ///
-/// `Float16` is available on Apple silicon,
-/// and unavailable on Intel when targeting macOS.'''
+/// On macOS, `Float16` is only available when targeting Apple silicon.
+/// On other supported platforms, `Float16` is available for all
+/// architectures. If the specified target supports 16-bit floating point
+/// arithmetic directly, those instructions will be used; otherwise Float16
+/// arithmetic will be emulated by the swift compiler and runtime.'''
 elif Self == 'Float':
     SelfDocComment = '''\
-/// A single-precision, floating-point value type.'''
+/// A single-precision (32-bit), floating-point value type.'''
 
 elif Self == 'Double':
     SelfDocComment = '''\
-/// A double-precision, floating-point value type.'''
+/// A double-precision (64-bit), floating-point value type.'''
 
 elif Self == 'Float80':
     SelfDocComment = '''\
 /// An extended-precision, floating-point value type.
 ///
-/// `Float80` is available on Intel
-/// when the target system supports an 80-bit long double type,
-/// and unavailable on Apple silicon.'''
+/// `Float80` is available on x86 if the target system's `long double` C type
+/// is 80-bit, and unavailable otherwise.'''
 
 else:
     raise ValueError('Unhandled float type.')
diff --git a/stdlib/public/core/GroupInfo.json b/stdlib/public/core/GroupInfo.json
index 655d20c95b06f..61917c68bb17d 100644
--- a/stdlib/public/core/GroupInfo.json
+++ b/stdlib/public/core/GroupInfo.json
@@ -182,9 +182,12 @@
       "FloatingPointTypes.swift",
       "FloatingPointRandom.swift"],
     "Vector": [
-      "SIMDConcreteOperations.swift",
+      "SIMDIntegerConcreteOperations.swift",
+      "SIMDFloatConcreteOperations.swift",
+      "SIMDMaskConcreteOperations.swift",
       "SIMDVector.swift",
-      "SIMDVectorTypes.swift"]}
+      "SIMDVectorTypes.swift"
+    ]}
   ],
   "Optional": [
     "Optional.swift"
@@ -202,9 +205,20 @@
   "Span": [
     "MutableRawSpan.swift",
     "MutableSpan.swift",
+    "OutputRawSpan.swift",
+    "OutputSpan.swift",
     "RawSpan.swift",
     "Span.swift"
   ],
+  "UTF8Span": [ 
+    "UTF8EncodingError.swift",
+    "UTF8Span.swift",
+    "UTF8SpanBits.swift",
+    "UTF8SpanComparisons.swift",
+    "UTF8SpanFundamentals.swift",
+    "UTF8SpanInternalHelpers.swift",
+    "UTF8SpanIterators.swift"
+  ],
   "Protocols": [
     "CompilerProtocols.swift",
     "ShadowProtocols.swift"
@@ -260,8 +274,7 @@
     "EmbeddedRuntime.swift",
     "EmbeddedStubs.swift",
     "EmbeddedPrint.swift",
-    "InlineArray.swift",
-    "SwiftSettings.swift"
+    "InlineArray.swift"
   ],
   "Result": [
     "Result.swift"
diff --git a/stdlib/public/core/HashTable.swift b/stdlib/public/core/HashTable.swift
index a51c4979b5896..6a93b1a755133 100644
--- a/stdlib/public/core/HashTable.swift
+++ b/stdlib/public/core/HashTable.swift
@@ -142,13 +142,13 @@ extension _HashTable {
     @inlinable
     @inline(__always)
     internal init(offset: Int) {
-      unsafe self.offset = offset
+      self.offset = offset
     }
 
     @inlinable
     @inline(__always)
     internal init(word: Int, bit: Int) {
-      unsafe self.offset = unsafe _UnsafeBitset.join(word: word, bit: bit)
+      self.offset = unsafe _UnsafeBitset.join(word: word, bit: bit)
     }
 
     @inlinable
@@ -172,7 +172,7 @@ extension _HashTable.Bucket: Equatable {
   @inline(__always)
   internal
   static func == (lhs: _HashTable.Bucket, rhs: _HashTable.Bucket) -> Bool {
-    return unsafe lhs.offset == rhs.offset
+    return lhs.offset == rhs.offset
   }
 }
 
@@ -181,7 +181,7 @@ extension _HashTable.Bucket: Comparable {
   @inline(__always)
   internal
   static func < (lhs: _HashTable.Bucket, rhs: _HashTable.Bucket) -> Bool {
-    return unsafe lhs.offset < rhs.offset
+    return lhs.offset < rhs.offset
   }
 }
 
@@ -199,7 +199,7 @@ extension _HashTable {
     @inlinable
     @inline(__always)
     internal init(bucket: Bucket, age: Int32) {
-      unsafe self.bucket = unsafe bucket
+      unsafe self.bucket = bucket
       unsafe self.age = age
     }
   }
@@ -316,7 +316,7 @@ extension _HashTable {
     var word = word
     while unsafe word < wordCount {
       if let bit = unsafe words[word].minimum {
-        return unsafe Bucket(word: word, bit: bit)
+        return Bucket(word: word, bit: bit)
       }
       word += 1
     }
@@ -326,9 +326,9 @@ extension _HashTable {
   @inlinable
   internal func occupiedBucket(after bucket: Bucket) -> Bucket {
     _internalInvariant(isValid(bucket))
-    let word = unsafe bucket.word
+    let word = bucket.word
     if let bit = unsafe words[word].intersecting(elementsAbove: bucket.bit).minimum {
-      return unsafe Bucket(word: word, bit: bit)
+      return Bucket(word: word, bit: bit)
     }
     return unsafe _firstOccupiedBucket(fromWord: word + 1)
   }
@@ -370,13 +370,13 @@ extension _HashTable {
     _internalInvariant(isValid(bucket))
     // Note that if we have only a single partial word, its out-of-bounds bits
     // are guaranteed to be all set, so the formula below gives correct results.
-    var word = unsafe bucket.word
+    var word = bucket.word
     if let bit =
       unsafe words[word]
         .complement
         .intersecting(elementsBelow: bucket.bit)
         .maximum {
-      return unsafe Bucket(word: word, bit: bit)
+      return Bucket(word: word, bit: bit)
     }
     var wrap = false
     while true {
@@ -387,7 +387,7 @@ extension _HashTable {
         word = unsafe wordCount - 1
       }
       if let bit = unsafe words[word].complement.maximum {
-        return unsafe Bucket(word: word, bit: bit)
+        return Bucket(word: word, bit: bit)
       }
     }
     fatalError()
@@ -398,13 +398,13 @@ extension _HashTable {
     _internalInvariant(isValid(bucket))
     // Note that if we have only a single partial word, its out-of-bounds bits
     // are guaranteed to be all set, so the formula below gives correct results.
-    var word = unsafe bucket.word
+    var word = bucket.word
     if let bit =
       unsafe words[word]
         .complement
         .subtracting(elementsBelow: bucket.bit)
         .minimum {
-      return unsafe Bucket(word: word, bit: bit)
+      return Bucket(word: word, bit: bit)
     }
     var wrap = false
     while true {
@@ -415,7 +415,7 @@ extension _HashTable {
         word = 0
       }
       if let bit = unsafe words[word].complement.minimum {
-        return unsafe Bucket(word: word, bit: bit)
+        return Bucket(word: word, bit: bit)
       }
     }
     fatalError()
@@ -438,7 +438,7 @@ extension _HashTable {
   internal func insertNew(hashValue: Int) -> Bucket {
     let hole = unsafe nextHole(atOrAfter: idealBucket(forHashValue: hashValue))
     unsafe insert(hole)
-    return unsafe hole
+    return hole
   }
 
   /// Insert a new entry for an element at `index`.
@@ -473,7 +473,7 @@ extension _HashTable {
     // If we've put a hole in a chain of contiguous elements, some element after
     // the hole may belong where the new hole is.
 
-    var hole = unsafe bucket
+    var hole = bucket
     var candidate = unsafe self.bucket(wrappedAfter: hole)
 
     guard unsafe _isOccupied(candidate) else {
@@ -489,19 +489,19 @@ extension _HashTable {
     // Relocate out-of-place elements in the chain, repeating until we get to
     // the end of the chain.
     while unsafe _isOccupied(candidate) {
-      let candidateHash = unsafe delegate.hashValue(at: candidate)
+      let candidateHash = delegate.hashValue(at: candidate)
       let ideal = unsafe idealBucket(forHashValue: candidateHash)
 
       // Does this element belong between start and hole?  We need two
       // separate tests depending on whether [start, hole] wraps around the
       // end of the storage.
-      let c0 = unsafe ideal >= start
-      let c1 = unsafe ideal <= hole
-      if unsafe start <= hole ? (c0 && c1) : (c0 || c1) {
-        unsafe delegate.moveEntry(from: candidate, to: hole)
-        unsafe hole = unsafe candidate
+      let c0 = ideal >= start
+      let c1 = ideal <= hole
+      if start <= hole ? (c0 && c1) : (c0 || c1) {
+        delegate.moveEntry(from: candidate, to: hole)
+        hole = candidate
       }
-      unsafe candidate = unsafe self.bucket(wrappedAfter: candidate)
+      candidate = unsafe self.bucket(wrappedAfter: candidate)
     }
 
     unsafe words[hole.word].uncheckedRemove(hole.bit)
diff --git a/stdlib/public/core/InlineArray.swift b/stdlib/public/core/InlineArray.swift
index bfa15d4f85378..dda7430d21dbf 100644
--- a/stdlib/public/core/InlineArray.swift
+++ b/stdlib/public/core/InlineArray.swift
@@ -46,7 +46,7 @@
 @_addressableForDependencies
 public struct InlineArray<let count: Int, Element: ~Copyable>: ~Copyable {
   @usableFromInline
-  internal let _storage: Builtin.FixedArray<count, Element>
+  internal var _storage: Builtin.FixedArray<count, Element>
 }
 
 @available(SwiftStdlib 6.2, *)
@@ -69,7 +69,11 @@ extension InlineArray where Element: ~Copyable {
   @_alwaysEmitIntoClient
   @_transparent
   internal var _address: UnsafePointer<Element> {
+#if $AddressOfProperty2
+    unsafe UnsafePointer<Element>(Builtin.unprotectedAddressOfBorrow(_storage))
+#else
     unsafe UnsafePointer<Element>(Builtin.unprotectedAddressOfBorrow(self))
+#endif
   }
 
   /// Returns a buffer pointer over the entire array.
@@ -80,13 +84,45 @@ extension InlineArray where Element: ~Copyable {
     unsafe UnsafeBufferPointer<Element>(start: _address, count: count)
   }
 
+  /// Returns a pointer to the first element in the array while performing stack
+  /// checking.
+  ///
+  /// Use this when the value of the pointer could potentially be directly used
+  /// by users (e.g. through the use of span or the unchecked subscript).
+  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal var _protectedAddress: UnsafePointer<Element> {
+#if $AddressOfProperty2
+    unsafe UnsafePointer<Element>(Builtin.addressOfBorrow(_storage))
+#else
+    unsafe UnsafePointer<Element>(Builtin.addressOfBorrow(self))
+#endif
+  }
+
+  /// Returns a buffer pointer over the entire array while performing stack
+  /// checking.
+  ///
+  /// Use this when the value of the pointer could potentially be directly used
+  /// by users (e.g. through the use of span or the unchecked subscript).
+  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal var _protectedBuffer: UnsafeBufferPointer<Element> {
+    unsafe UnsafeBufferPointer<Element>(start: _protectedAddress, count: count)
+  }
+
   /// Returns a mutable pointer to the first element in the array.
   @available(SwiftStdlib 6.2, *)
   @_alwaysEmitIntoClient
   @_transparent
   internal var _mutableAddress: UnsafeMutablePointer<Element> {
     mutating get {
+#if $AddressOfProperty2
+      unsafe UnsafeMutablePointer<Element>(Builtin.unprotectedAddressOf(&_storage))
+#else
       unsafe UnsafeMutablePointer<Element>(Builtin.unprotectedAddressOf(&self))
+#endif
     }
   }
 
@@ -103,9 +139,45 @@ extension InlineArray where Element: ~Copyable {
     }
   }
 
+  /// Returns a mutable pointer to the first element in the array while
+  /// performing stack checking.
+  ///
+  /// Use this when the value of the pointer could potentially be directly used
+  /// by users (e.g. through the use of span or the unchecked subscript).
+  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal var _protectedMutableAddress: UnsafeMutablePointer<Element> {
+    mutating get {
+#if $AddressOfProperty2
+      unsafe UnsafeMutablePointer<Element>(Builtin.addressof(&_storage))
+#else
+      unsafe UnsafeMutablePointer<Element>(Builtin.addressof(&self))
+#endif
+    }
+  }
+
+  /// Returns a mutable buffer pointer over the entire array while performing
+  /// stack checking.
+  ///
+  /// Use this when the value of the pointer could potentially be directly used
+  /// by users (e.g. through the use of span or the unchecked subscript).
+  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
+  @_transparent
+  internal var _protectedMutableBuffer: UnsafeMutableBufferPointer<Element> {
+    mutating get {
+      unsafe UnsafeMutableBufferPointer<Element>(
+        start: _protectedMutableAddress,
+        count: count
+      )
+    }
+  }
+
   /// Converts the given raw pointer, which points at an uninitialized array
   /// instance, to a mutable buffer suitable for initialization.
   @available(SwiftStdlib 6.2, *)
+  @unsafe
   @_alwaysEmitIntoClient
   @_transparent
   internal static func _initializationBuffer(
@@ -140,13 +212,10 @@ extension InlineArray where Element: ~Copyable {
   ///
   /// - Parameter body: A closure that returns an owned `Element` to emplace at
   ///   the passed in index.
-  ///
-  /// - Complexity: O(*n*), where *n* is the number of elements in the array.
   @available(SwiftStdlib 6.2, *)
   @_alwaysEmitIntoClient
   public init<E: Error>(_ body: (Index) throws(E) -> Element) throws(E) {
-#if $BuiltinEmplaceTypedThrows
-    self = try Builtin.emplace { (rawPtr) throws(E) -> () in
+    _storage = try Builtin.emplace { (rawPtr) throws(E) -> () in
       let buffer = unsafe Self._initializationBuffer(start: rawPtr)
 
       for i in 0 ..< count {
@@ -164,9 +233,6 @@ extension InlineArray where Element: ~Copyable {
         }
       }
     }
-#else
-    fatalError()
-#endif
   }
 
   /// Initializes every element in this array, by calling the given closure
@@ -188,22 +254,19 @@ extension InlineArray where Element: ~Copyable {
   ///   - next: A closure that takes an immutable borrow reference to the
   ///     preceding element, and returns an owned `Element` instance to emplace
   ///     into the array.
-  ///
-  /// - Complexity: O(*n*), where *n* is the number of elements in the array.
   @available(SwiftStdlib 6.2, *)
   @_alwaysEmitIntoClient
   public init<E: Error>(
     first: consuming Element,
     next: (borrowing Element) throws(E) -> Element
   ) throws(E) {
-#if $BuiltinEmplaceTypedThrows
     // FIXME: We should be able to mark 'Builtin.emplace' as '@once' or something
     //        to give the compiler enough information to know we will only run
     //        it once so it can consume the capture. For now, we use an optional
     //        and take the underlying value within the closure.
     var o: Element? = first
 
-    self = try Builtin.emplace { (rawPtr) throws(E) -> () in
+    _storage = try Builtin.emplace { (rawPtr) throws(E) -> () in
       let buffer = unsafe Self._initializationBuffer(start: rawPtr)
 
       guard Self.count > 0 else {
@@ -230,9 +293,21 @@ extension InlineArray where Element: ~Copyable {
         }
       }
     }
-#else
-    fatalError()
-#endif
+  }
+
+  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
+  public init<E: Error>(
+    initializingWith initializer: (inout OutputSpan<Element>) throws(E) -> Void
+  ) throws(E) {
+    _storage = try Builtin.emplace { (rawPtr) throws(E) -> () in
+      let buffer = unsafe Self._initializationBuffer(start: rawPtr)
+      _internalInvariant(Self.count == buffer.count)
+      var output = unsafe OutputSpan(buffer: buffer, initializedCount: 0)
+      try initializer(&output)
+      let initialized = unsafe output.finalize(for: buffer)
+      _precondition(count == initialized, "InlineArray initialization underflow")
+    }
   }
 }
 
@@ -241,12 +316,10 @@ extension InlineArray where Element: Copyable {
   /// Initializes every element in this array to a copy of the given value.
   ///
   /// - Parameter value: The instance to initialize this array with.
-  ///
-  /// - Complexity: O(*n*), where *n* is the number of elements in the array.
   @available(SwiftStdlib 6.2, *)
   @_alwaysEmitIntoClient
   public init(repeating value: Element) {
-    self = Builtin.emplace {
+    _storage = Builtin.emplace {
       let buffer = unsafe Self._initializationBuffer(start: $0)
 
       unsafe buffer.initialize(repeating: value)
@@ -272,14 +345,6 @@ extension InlineArray where Element: ~Copyable {
   @available(SwiftStdlib 6.2, *)
   public typealias Index = Int
 
-  // FIXME: Remove when SE-0452 "Integer Generic Parameters" is implemented.
-  @available(SwiftStdlib 6.2, *)
-  @_alwaysEmitIntoClient
-  @_transparent
-  public static var count: Int {
-    count
-  }
-
   /// The number of elements in the array.
   ///
   /// - Complexity: O(1)
@@ -410,12 +475,12 @@ extension InlineArray where Element: ~Copyable {
   public subscript(unchecked i: Index) -> Element {
     @_transparent
     unsafeAddress {
-      unsafe _address + i
+      unsafe _protectedAddress + i
     }
 
     @_transparent
     unsafeMutableAddress {
-      unsafe _mutableAddress + i
+      unsafe _protectedMutableAddress + i
     }
   }
 }
@@ -457,45 +522,33 @@ extension InlineArray where Element: ~Copyable {
 }
 
 //===----------------------------------------------------------------------===//
-// MARK: Span
+// MARK: - Span APIs
 //===----------------------------------------------------------------------===//
 
 @available(SwiftStdlib 6.2, *)
 extension InlineArray where Element: ~Copyable {
-
   @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
   public var span: Span<Element> {
     @lifetime(borrow self)
-    @_alwaysEmitIntoClient
+    @_transparent
     borrowing get {
-      fatalError("Span over InlineArray is not supported yet.")
+      let span = unsafe Span(_unsafeStart: _protectedAddress, count: count)
+      return unsafe _overrideLifetime(span, borrowing: self)
     }
   }
-}
-
-//===----------------------------------------------------------------------===//
-// MARK: - Unsafe APIs
-//===----------------------------------------------------------------------===//
-
-@available(SwiftStdlib 6.2, *)
-extension InlineArray where Element: ~Copyable {
-  // FIXME: @available(*, deprecated, renamed: "span.withUnsafeBufferPointer(_:)")
-  @available(SwiftStdlib 6.2, *)
-  @_alwaysEmitIntoClient
-  @_transparent
-  public borrowing func _withUnsafeBufferPointer<Result: ~Copyable, E: Error>(
-    _ body: (UnsafeBufferPointer<Element>) throws(E) -> Result
-  ) throws(E) -> Result {
-    try unsafe body(_buffer)
-  }
 
-  // FIXME: @available(*, deprecated, renamed: "mutableSpan.withUnsafeMutableBufferPointer(_:)")
   @available(SwiftStdlib 6.2, *)
   @_alwaysEmitIntoClient
-  @_transparent
-  public mutating func _withUnsafeMutableBufferPointer<Result: ~Copyable, E: Error>(
-    _ body: (UnsafeMutableBufferPointer<Element>) throws(E) -> Result
-  ) throws(E) -> Result {
-    try unsafe body(_mutableBuffer)
+  public var mutableSpan: MutableSpan<Element> {
+    @lifetime(&self)
+    @_transparent
+    mutating get {
+      let span = unsafe MutableSpan(
+        _unsafeStart: _protectedMutableAddress,
+        count: count
+      )
+      return unsafe _overrideLifetime(span, mutating: &self)
+    }
   }
 }
diff --git a/stdlib/public/core/Instant.swift b/stdlib/public/core/Instant.swift
index baec28e430320..64f75486564ea 100644
--- a/stdlib/public/core/Instant.swift
+++ b/stdlib/public/core/Instant.swift
@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 // A type that defines a specific point in time for a given `Clock`.
-@available(SwiftStdlib 5.7, *)
+@available(StdlibDeploymentTarget 5.7, *)
 public protocol InstantProtocol<Duration>: Comparable, Hashable, Sendable {
   associatedtype Duration: DurationProtocol
   func advanced(by duration: Duration) -> Self
diff --git a/stdlib/public/core/Int128.swift b/stdlib/public/core/Int128.swift
index 5713c4e61424b..e8c5281d29b92 100644
--- a/stdlib/public/core/Int128.swift
+++ b/stdlib/public/core/Int128.swift
@@ -76,7 +76,7 @@ public struct Int128: Sendable {
   public var _value: Builtin.Int128 {
     @_transparent
     get {
-      unsafeBitCast(self, to: Builtin.Int128.self)
+      unsafe unsafeBitCast(self, to: Builtin.Int128.self)
     }
 
     @_transparent
@@ -88,7 +88,7 @@ public struct Int128: Sendable {
   @available(SwiftStdlib 6.0, *)
   @_transparent
   public init(_ _value: Builtin.Int128) {
-    self = unsafeBitCast(_value, to: Self.self)
+    self = unsafe unsafeBitCast(_value, to: Self.self)
   }
 #endif
 
diff --git a/stdlib/public/core/Integers.swift b/stdlib/public/core/Integers.swift
index 8f5653262fcd9..89a7ef2e5bdb8 100644
--- a/stdlib/public/core/Integers.swift
+++ b/stdlib/public/core/Integers.swift
@@ -1705,12 +1705,6 @@ extension BinaryInteger {
   }
 }
 
-#if !$Embedded
-public typealias _LosslessStringConvertibleOrNone = LosslessStringConvertible
-#else
-public protocol _LosslessStringConvertibleOrNone {}
-#endif
-
 //===----------------------------------------------------------------------===//
 //===--- FixedWidthInteger ------------------------------------------------===//
 //===----------------------------------------------------------------------===//
@@ -1779,7 +1773,7 @@ public protocol _LosslessStringConvertibleOrNone {}
 /// customization points for arithmetic operations. When you provide just those
 /// methods, the standard library provides default implementations for all
 /// other arithmetic methods and operators.
-public protocol FixedWidthInteger: BinaryInteger, _LosslessStringConvertibleOrNone
+public protocol FixedWidthInteger: BinaryInteger, LosslessStringConvertible
 where Magnitude: FixedWidthInteger & UnsignedInteger,
       Stride: FixedWidthInteger & SignedInteger {
   /// The number of bits used for the underlying binary representation of
@@ -2158,6 +2152,7 @@ where Magnitude: FixedWidthInteger & UnsignedInteger,
 
 extension FixedWidthInteger {
   @inlinable
+  @_transparent
   public var bitWidth: Int { return Self.bitWidth }
 
   @inlinable
@@ -2770,7 +2765,7 @@ extension FixedWidthInteger {
   }
 
   @inlinable // FIXME(inline-always)
-  @inline(__always)
+  @_transparent
   public init<T: BinaryInteger>(truncatingIfNeeded source: T) {
     if Self.bitWidth <= Int.bitWidth {
       self = Self(_truncatingBits: source._lowWord)
@@ -3015,7 +3010,7 @@ extension UnsignedInteger {
   /// This property is always `false` for unsigned integer types.
   @inlinable // FIXME(inline-always)
   public static var isSigned: Bool {
-    @inline(__always)
+    @_transparent
     get { return false }
   }
 }
@@ -3088,9 +3083,9 @@ extension UnsignedInteger where Self: FixedWidthInteger {
     _ dividend: (high: Self, low: Magnitude)
   ) -> (quotient: Self, remainder: Self) {
     // Validate preconditions to guarantee that the quotient is representable.
-    precondition(self != .zero, "Division by zero")
-    precondition(dividend.high < self,
-                 "Dividend.high must be smaller than divisor")
+    _precondition(self != .zero, "Division by zero")
+    _precondition(dividend.high < self,
+                  "Dividend.high must be smaller than divisor")
     // UnsignedInteger should have a Magnitude = Self constraint, but does not,
     // so we have to do this conversion (we can't easily add the constraint
     // because it changes how generic signatures constrained to
@@ -3228,7 +3223,7 @@ extension SignedInteger {
   /// This property is always `true` for signed integer types.
   @inlinable // FIXME(inline-always)
   public static var isSigned: Bool {
-    @inline(__always)
+    @_transparent
     get { return true }
   }
 }
@@ -3335,8 +3330,8 @@ extension SignedInteger where Self: FixedWidthInteger {
       // It is possible that the quotient is representable but its magnitude
       // is not representable as Self (if quotient is Self.min), so we have
       // to handle that case carefully here.
-      precondition(unsignedQuotient <= Self.min.magnitude,
-                   "Quotient is not representable.")
+      _precondition(unsignedQuotient <= Self.min.magnitude,
+                    "Quotient is not representable.")
       quotient = Self(truncatingIfNeeded: 0 &- unsignedQuotient)
     } else {
       quotient = Self(unsignedQuotient)
diff --git a/stdlib/public/core/KeyPath.swift b/stdlib/public/core/KeyPath.swift
index f0ebf1ceba403..251e95467086c 100644
--- a/stdlib/public/core/KeyPath.swift
+++ b/stdlib/public/core/KeyPath.swift
@@ -24,6 +24,11 @@ internal func _abstract(
 #endif
 }
 
+@_alignment(16)
+struct _SixteenAligned {
+  let x: UInt8
+}
+
 // MARK: Type-erased abstract base classes
 
 // NOTE: older runtimes had Swift.AnyKeyPath as the ObjC name.
@@ -80,9 +85,10 @@ public class AnyKeyPath: _AppendKeyPath {
     unsafe _kvcKeyPathStringPtr = UnsafePointer<CChar>(bitPattern: -offset - 1)
 #elseif _pointerBitWidth(_32)
     if offset <= maximumOffsetOn32BitArchitecture {
-      _kvcKeyPathStringPtr = UnsafePointer<CChar>(bitPattern: (offset + 1))
+      unsafe _kvcKeyPathStringPtr =
+           UnsafePointer<CChar>(bitPattern: (offset + 1))
     } else {
-      _kvcKeyPathStringPtr = nil
+      unsafe _kvcKeyPathStringPtr = nil
     }
 #else
     // Don't assign anything.
@@ -104,7 +110,7 @@ public class AnyKeyPath: _AppendKeyPath {
     }
     return offset
 #elseif _pointerBitWidth(_32)
-    let offset = Int(bitPattern: _kvcKeyPathStringPtr) &- 1
+    let offset = unsafe Int(bitPattern: _kvcKeyPathStringPtr) &- 1
     // Pointers above 0x7fffffff will come in as negative numbers which are
     // less than maximumOffsetOn32BitArchitecture, be sure to reject them.
     if offset >= 0, offset <= maximumOffsetOn32BitArchitecture {
@@ -153,8 +159,37 @@ public class AnyKeyPath: _AppendKeyPath {
   ) -> Self {
     _internalInvariant(bytes > 0 && bytes % 4 == 0,
                  "capacity must be multiple of 4 bytes")
-    let result = Builtin.allocWithTailElems_1(self, (bytes/4)._builtinWordValue,
-                                              Int32.self)
+
+    // Subtract the buffer header and any padding it may have from the number of
+    // bytes we need to allocate. The alloc below has a 0 sized 16 byte aligned
+    // tail element that will force the compiler to insert buffer header + any
+    // padding necessary to accomodate.
+    let bytesWithoutHeader = bytes &- MemoryLayout<Int>.size
+
+    let result = Builtin.allocWithTailElems_2(
+      self,
+
+      // This tail element accomplishes two things:
+      //   1. Guarantees a 16 byte alignment for the allocated object pointer.
+      //   2. Forces the compiler to add padding after the kvc string to support
+      //      this 16 byte aligned tail element.
+      //
+      // The size of keypath objects before any tail elements is 24 bytes large
+      // on 64 bit platforms and 12 bytes large on 32 bit platforms.
+      // (Isa, RC, and KVC). The amount of padding bytes needed after the kvc
+      // string pointer to support a 16 byte aligned tail element is the exact
+      // same amount of bytes that the keypath buffer header occupies on both
+      // 64 & 32 bit platforms (because we always start component headers on
+      // pointer aligned addresses). That is the purpose for the subtraction
+      // above. The result of this tail element should just be the 16 byte
+      // pointer aligned requirement and no extra bytes allocated.
+      0._builtinWordValue,
+      _SixteenAligned.self,
+
+      (bytesWithoutHeader/4)._builtinWordValue,
+      Int32.self
+    )
+
     unsafe result._kvcKeyPathStringPtr = nil
     let base = UnsafeMutableRawPointer(Builtin.projectTailElems(result,
                                                                 Int32.self))
@@ -183,9 +218,9 @@ public class AnyKeyPath: _AppendKeyPath {
       var offset = 0
       while true {
         let (rawComponent, optNextType) = unsafe buffer.next()
-        switch unsafe rawComponent.header.kind {
+        switch rawComponent.header.kind {
         case .struct:
-          unsafe offset += rawComponent._structOrClassOffset
+          offset += rawComponent._structOrClassOffset
 
         case .class, .computed, .optionalChain, .optionalForce, .optionalWrap, .external:
           return .none
@@ -678,7 +713,7 @@ internal struct ComputedPropertyID: Hashable {
 }
 
 @_unavailableInEmbedded
-@unsafe
+@safe
 internal struct ComputedAccessorsPtr {
 #if INTERNAL_CHECKS_ENABLED
   internal let header: RawKeyPathComponent.Header
@@ -687,7 +722,7 @@ internal struct ComputedAccessorsPtr {
 
   init(header: RawKeyPathComponent.Header, value: UnsafeRawPointer) {
 #if INTERNAL_CHECKS_ENABLED
-    unsafe self.header = unsafe header
+    self.header = header
 #endif
     unsafe self._value = unsafe value
   }
@@ -714,14 +749,14 @@ internal struct ComputedAccessorsPtr {
 
   internal var getterPtr: UnsafeRawPointer {
 #if INTERNAL_CHECKS_ENABLED
-    unsafe _internalInvariant(header.kind == .computed,
+    _internalInvariant(header.kind == .computed,
                  "not a computed property")
 #endif
     return unsafe _value
   }
   internal var setterPtr: UnsafeRawPointer {
 #if INTERNAL_CHECKS_ENABLED
-    unsafe _internalInvariant(header.isComputedSettable,
+    _internalInvariant(header.isComputedSettable,
                  "not a settable property")
 #endif
     return unsafe _value + MemoryLayout<Int>.size
@@ -738,7 +773,7 @@ internal struct ComputedAccessorsPtr {
   internal func nonmutatingSetter<CurValue, NewValue>()
       -> NonmutatingSetter<CurValue, NewValue> {
 #if INTERNAL_CHECKS_ENABLED
-    unsafe _internalInvariant(header.isComputedSettable && !header.isComputedMutating,
+    _internalInvariant(header.isComputedSettable && !header.isComputedMutating,
                  "not a nonmutating settable property")
 #endif
 
@@ -750,7 +785,7 @@ internal struct ComputedAccessorsPtr {
   internal func mutatingSetter<CurValue, NewValue>()
       -> MutatingSetter<CurValue, NewValue> {
 #if INTERNAL_CHECKS_ENABLED
-    unsafe _internalInvariant(header.isComputedSettable && header.isComputedMutating,
+    _internalInvariant(header.isComputedSettable && header.isComputedMutating,
                  "not a mutating settable property")
 #endif
 
@@ -838,7 +873,7 @@ internal struct ComputedArgumentWitnessesPtr {
 }
 
 @_unavailableInEmbedded
-@unsafe
+@safe
 internal enum KeyPathComponent {
   @unsafe
   internal struct ArgumentRef {
@@ -890,7 +925,7 @@ internal enum KeyPathComponent {
 @_unavailableInEmbedded
 extension KeyPathComponent: @unsafe Hashable {
   internal static func ==(a: KeyPathComponent, b: KeyPathComponent) -> Bool {
-    switch unsafe (a, b) {
+    switch (a, b) {
     case (.struct(offset: let a), .struct(offset: let b)),
          (.class (offset: let a), .class (offset: let b)):
       return a == b
@@ -948,7 +983,7 @@ extension KeyPathComponent: @unsafe Hashable {
         }
       }
     }
-    switch unsafe self {
+    switch self {
     case .struct(offset: let a):
       hasher.combine(0)
       hasher.combine(a)
@@ -1119,13 +1154,170 @@ internal enum KeyPathComputedIDResolution {
 }
 
 @_unavailableInEmbedded
-@unsafe
+internal struct ComputedArgumentSize {
+  var value: UInt
+
+  @_unavailableInEmbedded
+  static var sizeMask: UInt {
+#if _pointerBitWidth(_64)
+    0x3FFF_FFFF_FFFF_FFFF
+#elseif _pointerBitWidth(_32)
+    0xFFF_FFFF
+#else
+#warning("Unsupported platform")
+    fatalError()
+#endif
+  }
+
+  @_unavailableInEmbedded
+  static var paddingMask: UInt {
+#if _pointerBitWidth(_64)
+    0x4000_0000_0000_0000
+#elseif _pointerBitWidth(_32)
+    0x3000_0000
+#else
+#warning("Unsupported platform")
+    fatalError()
+#endif
+  }
+
+  @_unavailableInEmbedded
+  static var paddingShift: UInt {
+#if _pointerBitWidth(_64)
+    62
+#elseif _pointerBitWidth(_32)
+    28
+#else
+#warning("Unsupported platform")
+    fatalError()
+#endif
+  }
+
+  @_unavailableInEmbedded
+  static var alignmentMask: UInt {
+#if _pointerBitWidth(_64)
+    0x8000_0000_0000_0000
+#elseif _pointerBitWidth(_32)
+    0x6000_0000
+#else
+#warning("Unsupported platform")
+    fatalError()
+#endif
+  }
+
+  @_unavailableInEmbedded
+  static var alignmentShift: UInt {
+#if _pointerBitWidth(_64)
+    63
+#elseif _pointerBitWidth(_32)
+    30
+#else
+#warning("Unsupported platform")
+    fatalError()
+#endif
+  }
+
+  init(_ argSize: Int) {
+    value = UInt(truncatingIfNeeded: argSize)
+  }
+
+  // The size of just the arguments only, ignoring padding.
+  var argumentSize: Int {
+    Int(truncatingIfNeeded: value & Self.sizeMask)
+  }
+
+  // The total size of the argument buffer.
+  var totalSize: Int {
+    argumentSize &+ padding
+  }
+
+  // The number of padding bytes required so that the argument is properly
+  // aligned in the keypath buffer. This is in the top 3rd and 4th bits for 32
+  // bit platforms (because they need to represent 8 and 16 overaligned types)
+  // and top 2nd bit for 64 bit platforms (because they only need to represent 16
+  // alignment).
+  var padding: Int {
+    get {
+      let mask = value & Self.paddingMask
+      let shift = mask &>> Self.paddingShift
+      return Int(truncatingIfNeeded: shift) &* MemoryLayout<Int>.size
+    }
+
+    set {
+      let new = UInt(truncatingIfNeeded: newValue)
+      let reduced = new / UInt(truncatingIfNeeded: MemoryLayout<Int>.size)
+      let shift = reduced &<< Self.paddingShift
+      value &= ~Self.paddingMask
+      value |= shift
+    }
+  }
+
+  // If the arguments have an alignment greater than the platform's pointer
+  // alignment, then this structure records the argument's alignment. Even if
+  // the argument didn't require padding, we still record the argument's
+  // alignment here to prevent overallocation on keypath appends (because a leaf
+  // component may suddenly need padding or lose padding). This returns 0 if the
+  // argument had less than or equal to the platform's pointer alignment. The
+  // only valid values of this on 64 bit are 16 and 0, while on 32 it is 16, 8,
+  // and 0. Top bit on 64 bit platforms and top 2 bits on 32 bit platforms.
+  @_unavailableInEmbedded
+  var alignment: Int {
+    get {
+      let mask = value & Self.alignmentMask
+      let shift = mask &>> Self.alignmentShift
+
+#if _pointerBitWidth(_64)
+      // On 64 bit, the only higher alignment a type could have is 16 byte.
+      return shift == 1 ? 16 : 0
+#elseif _pointerBitWidth(_32)
+      switch shift {
+      case 1:
+        return 8
+      case 2:
+        return 16
+      default:
+        return 0
+      }
+#else
+#warning("Unsupported platform")
+      fatalError()
+#endif
+    }
+
+    set {
+      var reduced: UInt = 0
+
+#if _pointerBitWidth(_64)
+      reduced = newValue == 16 ? 1 : 0
+#elseif _pointerBitWidth(_32)
+      switch newValue {
+      case 8:
+        reduced = 1
+      case 16:
+        reduced = 2
+      default:
+        reduced = 0
+      }
+#else
+#warning("Unsupported platform")
+      fatalError()
+#endif
+
+      let shift = reduced &<< Self.alignmentShift
+      value &= ~Self.alignmentMask
+      value |= shift
+    }
+  }
+}
+
+@_unavailableInEmbedded
+@safe
 internal struct RawKeyPathComponent {
-  internal var header: Header
+  @safe internal var header: Header
   internal var body: UnsafeRawBufferPointer
 
   internal init(header: Header, body: UnsafeRawBufferPointer) {
-    unsafe self.header = unsafe header
+    self.header = header
     unsafe self.body = unsafe body
   }
 
@@ -1138,74 +1330,74 @@ internal struct RawKeyPathComponent {
     internal var _value: UInt32
 
     init(discriminator: UInt32, payload: UInt32) {
-      unsafe _value = 0
-      unsafe self.discriminator = discriminator
-      unsafe self.payload = payload
+      _value = 0
+      self.discriminator = discriminator
+      self.payload = payload
     }
 
     internal var discriminator: UInt32 {
       get {
-        return unsafe (_value & Header.discriminatorMask) &>> Header.discriminatorShift
+        return (_value & Header.discriminatorMask) &>> Header.discriminatorShift
       }
       set {
-        let shifted = unsafe newValue &<< Header.discriminatorShift
-        unsafe _internalInvariant(shifted & Header.discriminatorMask == shifted,
+        let shifted = newValue &<< Header.discriminatorShift
+        _internalInvariant(shifted & Header.discriminatorMask == shifted,
                      "discriminator doesn't fit")
-        unsafe _value = unsafe _value & ~Header.discriminatorMask | shifted
+        _value = _value & ~Header.discriminatorMask | shifted
       }
     }
     internal var payload: UInt32 {
       get {
-        return unsafe _value & Header.payloadMask
+        return _value & Header.payloadMask
       }
       set {
-        unsafe _internalInvariant(newValue & Header.payloadMask == newValue,
+        _internalInvariant(newValue & Header.payloadMask == newValue,
                      "payload too big")
-        unsafe _value = unsafe _value & ~Header.payloadMask | newValue
+        _value = _value & ~Header.payloadMask | newValue
       }
     }
     internal var storedOffsetPayload: UInt32 {
       get {
-        unsafe _internalInvariant(kind == .struct || kind == .class,
+        _internalInvariant(kind == .struct || kind == .class,
                      "not a stored component")
-        return unsafe _value & Header.storedOffsetPayloadMask
+        return _value & Header.storedOffsetPayloadMask
       }
       set {
-        unsafe _internalInvariant(kind == .struct || kind == .class,
+        _internalInvariant(kind == .struct || kind == .class,
                      "not a stored component")
-        unsafe _internalInvariant(newValue & Header.storedOffsetPayloadMask == newValue,
+        _internalInvariant(newValue & Header.storedOffsetPayloadMask == newValue,
                      "payload too big")
-        unsafe _value = unsafe _value & ~Header.storedOffsetPayloadMask | newValue
+        _value = _value & ~Header.storedOffsetPayloadMask | newValue
       }
     }
     internal var endOfReferencePrefix: Bool {
       get {
-        return unsafe _value & Header.endOfReferencePrefixFlag != 0
+        return _value & Header.endOfReferencePrefixFlag != 0
       }
       set {
         if newValue {
-          unsafe _value |= Header.endOfReferencePrefixFlag
+          _value |= Header.endOfReferencePrefixFlag
         } else {
-          unsafe _value &= ~Header.endOfReferencePrefixFlag
+          _value &= ~Header.endOfReferencePrefixFlag
         }
       }
     }
 
     internal var kind: KeyPathComponentKind {
-      switch unsafe (discriminator, payload) {
-      case (unsafe Header.externalTag, _):
+      switch (discriminator, payload) {
+      case (Header.externalTag, _):
         return .external
-      case (unsafe Header.structTag, _):
+      case (Header.structTag, _):
         return .struct
-      case (unsafe Header.classTag, _):
+      case (Header.classTag, _):
         return .class
-      case (unsafe Header.computedTag, _):
+      case (Header.computedTag, _):
         return .computed
-      case (unsafe Header.optionalTag, unsafe Header.optionalChainPayload):
+      case (Header.optionalTag, Header.optionalChainPayload):
         return .optionalChain
-      case (unsafe Header.optionalTag, unsafe Header.optionalWrapPayload):
+      case (Header.optionalTag, Header.optionalWrapPayload):
         return .optionalWrap
-      case (unsafe Header.optionalTag, unsafe Header.optionalForcePayload):
+      case (Header.optionalTag, Header.optionalForcePayload):
         return .optionalForce
       default:
         _internalInvariantFailure("invalid header")
@@ -1269,24 +1461,24 @@ internal struct RawKeyPathComponent {
     }
 
     internal var isStoredMutable: Bool {
-      unsafe _internalInvariant(kind == .struct || kind == .class)
-      return unsafe _value & Header.storedMutableFlag != 0
+      _internalInvariant(kind == .struct || kind == .class)
+      return _value & Header.storedMutableFlag != 0
     }
 
     internal static var computedMutatingFlag: UInt32 {
       return _SwiftKeyPathComponentHeader_ComputedMutatingFlag
     }
     internal var isComputedMutating: Bool {
-      unsafe _internalInvariant(kind == .computed)
-      return unsafe _value & Header.computedMutatingFlag != 0
+      _internalInvariant(kind == .computed)
+      return _value & Header.computedMutatingFlag != 0
     }
 
     internal static var computedSettableFlag: UInt32 {
       return _SwiftKeyPathComponentHeader_ComputedSettableFlag
     }
     internal var isComputedSettable: Bool {
-      unsafe _internalInvariant(kind == .computed)
-      return unsafe _value & Header.computedSettableFlag != 0
+      _internalInvariant(kind == .computed)
+      return _value & Header.computedSettableFlag != 0
     }
 
     internal static var computedIDByStoredPropertyFlag: UInt32 {
@@ -1296,8 +1488,8 @@ internal struct RawKeyPathComponent {
       return _SwiftKeyPathComponentHeader_ComputedIDByVTableOffsetFlag
     }
     internal var computedIDKind: KeyPathComputedIDKind {
-      let storedProperty = unsafe _value & Header.computedIDByStoredPropertyFlag != 0
-      let vtableOffset = unsafe _value & Header.computedIDByVTableOffsetFlag != 0
+      let storedProperty = _value & Header.computedIDByStoredPropertyFlag != 0
+      let vtableOffset = _value & Header.computedIDByVTableOffsetFlag != 0
 
       switch (storedProperty, vtableOffset) {
       case (true, true):
@@ -1315,8 +1507,8 @@ internal struct RawKeyPathComponent {
       return _SwiftKeyPathComponentHeader_ComputedHasArgumentsFlag
     }
     internal var hasComputedArguments: Bool {
-      unsafe _internalInvariant(kind == .computed)
-      return unsafe _value & Header.computedHasArgumentsFlag != 0
+      _internalInvariant(kind == .computed)
+      return _value & Header.computedHasArgumentsFlag != 0
     }
 
     // If a computed component is instantiated from an external property
@@ -1328,14 +1520,14 @@ internal struct RawKeyPathComponent {
     }
     internal var isComputedInstantiatedFromExternalWithArguments: Bool {
       get {
-        unsafe _internalInvariant(kind == .computed)
+        _internalInvariant(kind == .computed)
         return
-          unsafe _value & Header.computedInstantiatedFromExternalWithArgumentsFlag != 0
+          _value & Header.computedInstantiatedFromExternalWithArgumentsFlag != 0
       }
       set {
-        unsafe _internalInvariant(kind == .computed)
-        unsafe _value =
-            unsafe _value & ~Header.computedInstantiatedFromExternalWithArgumentsFlag
+        _internalInvariant(kind == .computed)
+        _value =
+            _value & ~Header.computedInstantiatedFromExternalWithArgumentsFlag
           | (newValue ? Header.computedInstantiatedFromExternalWithArgumentsFlag
                       : 0)
       }
@@ -1360,14 +1552,14 @@ internal struct RawKeyPathComponent {
       return _SwiftKeyPathComponentHeader_ComputedIDUnresolvedFunctionCall
     }
     internal var computedIDResolution: KeyPathComputedIDResolution {
-      switch unsafe payload & Header.computedIDResolutionMask {
-      case unsafe Header.computedIDResolved:
+      switch payload & Header.computedIDResolutionMask {
+      case Header.computedIDResolved:
         return .resolved
-      case unsafe Header.computedIDResolvedAbsolute:
+      case Header.computedIDResolvedAbsolute:
         return .resolvedAbsolute
-      case unsafe Header.computedIDUnresolvedIndirectPointer:
+      case Header.computedIDUnresolvedIndirectPointer:
         return .indirectPointer
-      case unsafe Header.computedIDUnresolvedFunctionCall:
+      case Header.computedIDUnresolvedFunctionCall:
         return .functionCall
       default:
         _internalInvariantFailure("invalid key path resolution")
@@ -1381,27 +1573,27 @@ internal struct RawKeyPathComponent {
     }
 
     internal var isTrivialPropertyDescriptor: Bool {
-      return unsafe _value ==
+      return _value ==
         _SwiftKeyPathComponentHeader_TrivialPropertyDescriptorMarker
     }
 
     /// If this is the header for a component in a key path pattern, return
     /// the size of the body of the component.
     internal var patternComponentBodySize: Int {
-      return unsafe _componentBodySize(forPropertyDescriptor: false)
+      return _componentBodySize(forPropertyDescriptor: false)
     }
 
     /// If this is the header for a property descriptor, return
     /// the size of the body of the component.
     internal var propertyDescriptorBodySize: Int {
-      if unsafe isTrivialPropertyDescriptor { return 0 }
-      return unsafe _componentBodySize(forPropertyDescriptor: true)
+      if isTrivialPropertyDescriptor { return 0 }
+      return _componentBodySize(forPropertyDescriptor: true)
     }
 
     internal func _componentBodySize(forPropertyDescriptor: Bool) -> Int {
-      switch unsafe kind {
+      switch kind {
       case .struct, .class:
-        if unsafe storedOffsetPayload == Header.unresolvedFieldOffsetPayload
+        if storedOffsetPayload == Header.unresolvedFieldOffsetPayload
            || storedOffsetPayload == Header.outOfLineOffsetPayload
            || storedOffsetPayload == Header.unresolvedIndirectOffsetPayload {
           // A 32-bit offset is stored in the body.
@@ -1414,19 +1606,19 @@ internal struct RawKeyPathComponent {
         // The body holds a pointer to the external property descriptor,
         // and some number of substitution arguments, the count of which is
         // in the payload.
-        return unsafe 4 &* (1 &+ Int(payload))
+        return 4 &* (1 &+ Int(payload))
 
       case .computed:
         // The body holds at minimum the id and getter.
         var size = 8
         // If settable, it also holds the setter.
-        if unsafe isComputedSettable {
+        if isComputedSettable {
           size &+= 4
         }
         // If there are arguments, there's also a layout function,
         // witness table, and initializer function.
         // Property descriptors never carry argument information, though.
-        if unsafe !forPropertyDescriptor && hasComputedArguments {
+        if !forPropertyDescriptor && hasComputedArguments {
           size &+= 12
         }
 
@@ -1439,17 +1631,17 @@ internal struct RawKeyPathComponent {
     }
 
     init(optionalForce: ()) {
-      unsafe self.init(discriminator: Header.optionalTag,
+      self.init(discriminator: Header.optionalTag,
                 payload: Header.optionalForcePayload)
     }
 
     init(optionalWrap: ()) {
-      unsafe self.init(discriminator: Header.optionalTag,
+      self.init(discriminator: Header.optionalTag,
                 payload: Header.optionalWrapPayload)
     }
 
     init(optionalChain: ()) {
-      unsafe self.init(discriminator: Header.optionalTag,
+      self.init(discriminator: Header.optionalTag,
                 payload: Header.optionalChainPayload)
     }
 
@@ -1458,14 +1650,14 @@ internal struct RawKeyPathComponent {
          inlineOffset: UInt32) {
       let discriminator: UInt32
       switch kind {
-      case .struct: discriminator = unsafe Header.structTag
-      case .class: discriminator = unsafe Header.classTag
+      case .struct: discriminator = Header.structTag
+      case .class: discriminator = Header.classTag
       }
 
-      unsafe _internalInvariant(inlineOffset <= Header.maximumOffsetPayload)
-      let payload = unsafe inlineOffset
+      _internalInvariant(inlineOffset <= Header.maximumOffsetPayload)
+      let payload = inlineOffset
         | (mutable ? Header.storedMutableFlag : 0)
-      unsafe self.init(discriminator: discriminator,
+      self.init(discriminator: discriminator,
                 payload: payload)
     }
 
@@ -1473,14 +1665,14 @@ internal struct RawKeyPathComponent {
          mutable: Bool) {
       let discriminator: UInt32
       switch kind {
-      case .struct: discriminator = unsafe Header.structTag
-      case .class: discriminator = unsafe Header.classTag
+      case .struct: discriminator = Header.structTag
+      case .class: discriminator = Header.classTag
       }
 
-      let payload = unsafe Header.outOfLineOffsetPayload
+      let payload = Header.outOfLineOffsetPayload
         | (mutable ? Header.storedMutableFlag : 0)
 
-      unsafe self.init(discriminator: discriminator,
+      self.init(discriminator: discriminator,
                 payload: payload)
     }
 
@@ -1489,9 +1681,9 @@ internal struct RawKeyPathComponent {
          settable: Bool,
          hasArguments: Bool,
          instantiatedFromExternalWithArguments: Bool) {
-      let discriminator = unsafe Header.computedTag
+      let discriminator = Header.computedTag
       var payload =
-          unsafe (mutating ? Header.computedMutatingFlag : 0)
+          (mutating ? Header.computedMutatingFlag : 0)
         | (settable ? Header.computedSettableFlag : 0)
         | (hasArguments ? Header.computedHasArgumentsFlag : 0)
         | (instantiatedFromExternalWithArguments
@@ -1500,20 +1692,20 @@ internal struct RawKeyPathComponent {
       case .pointer:
         break
       case .storedPropertyIndex:
-        unsafe payload |= Header.computedIDByStoredPropertyFlag
+        payload |= Header.computedIDByStoredPropertyFlag
       case .vtableOffset:
-        unsafe payload |= Header.computedIDByVTableOffsetFlag
+        payload |= Header.computedIDByVTableOffsetFlag
       }
-      unsafe self.init(discriminator: discriminator,
+      self.init(discriminator: discriminator,
                 payload: payload)
     }
   }
 
   internal var bodySize: Int {
     let ptrSize = MemoryLayout<Int>.size
-    switch unsafe header.kind {
+    switch header.kind {
     case .struct, .class:
-      if unsafe header.storedOffsetPayload == Header.outOfLineOffsetPayload {
+      if header.storedOffsetPayload == Header.outOfLineOffsetPayload {
         return 4 // overflowed
       }
       return 0
@@ -1523,19 +1715,19 @@ internal struct RawKeyPathComponent {
       return 0
     case .computed:
       // align to pointer, minimum two pointers for id and get
-      var total = unsafe Header.pointerAlignmentSkew &+ ptrSize &* 2
+      var total = Header.pointerAlignmentSkew &+ ptrSize &* 2
       // additional word for a setter
-      if unsafe header.isComputedSettable {
+      if header.isComputedSettable {
         total &+= ptrSize
       }
       // include the argument size
-      if unsafe header.hasComputedArguments {
+      if header.hasComputedArguments {
         // two words for argument header: size, witnesses
         total &+= ptrSize &* 2
         // size of argument area
-        unsafe total &+= _computedArgumentSize
-        if unsafe header.isComputedInstantiatedFromExternalWithArguments {
-          unsafe total &+= Header.externalWithArgumentsExtraSize
+        total &+= _computedArgumentSize.totalSize
+        if header.isComputedInstantiatedFromExternalWithArguments {
+          total &+= Header.externalWithArgumentsExtraSize
         }
       }
       return total
@@ -1543,37 +1735,37 @@ internal struct RawKeyPathComponent {
   }
 
   internal var _structOrClassOffset: Int {
-    unsafe _internalInvariant(header.kind == .struct || header.kind == .class,
+    _internalInvariant(header.kind == .struct || header.kind == .class,
                  "no offset for this kind")
     // An offset too large to fit inline is represented by a signal and stored
     // in the body.
-    if unsafe header.storedOffsetPayload == Header.outOfLineOffsetPayload {
+    if header.storedOffsetPayload == Header.outOfLineOffsetPayload {
       // Offset overflowed into body
       unsafe _internalInvariant(body.count >= MemoryLayout<UInt32>.size,
                    "component not big enough")
       return Int(truncatingIfNeeded: unsafe body.load(as: UInt32.self))
     }
-    return unsafe Int(truncatingIfNeeded: header.storedOffsetPayload)
+    return Int(truncatingIfNeeded: header.storedOffsetPayload)
   }
 
   internal var _computedIDValue: Int {
-    unsafe _internalInvariant(header.kind == .computed,
+    _internalInvariant(header.kind == .computed,
                  "not a computed property")
     return unsafe body.load(fromByteOffset: Header.pointerAlignmentSkew,
                      as: Int.self)
   }
 
   internal var _computedID: ComputedPropertyID {
-    unsafe _internalInvariant(header.kind == .computed,
+    _internalInvariant(header.kind == .computed,
                  "not a computed property")
 
-    return unsafe ComputedPropertyID(
+    return ComputedPropertyID(
       value: _computedIDValue,
       kind: header.computedIDKind)
   }
 
   internal var _computedAccessors: ComputedAccessorsPtr {
-    unsafe _internalInvariant(header.kind == .computed,
+    _internalInvariant(header.kind == .computed,
                  "not a computed property")
 
     return unsafe ComputedAccessorsPtr(
@@ -1583,7 +1775,7 @@ internal struct RawKeyPathComponent {
   }
 
   internal var _computedArgumentHeaderPointer: UnsafeRawPointer {
-    unsafe _internalInvariant(header.hasComputedArguments, "no arguments")
+    _internalInvariant(header.hasComputedArguments, "no arguments")
 
     return unsafe body.baseAddress._unsafelyUnwrappedUnchecked
       + Header.pointerAlignmentSkew
@@ -1591,8 +1783,8 @@ internal struct RawKeyPathComponent {
          (header.isComputedSettable ? 3 : 2)
   }
 
-  internal var _computedArgumentSize: Int {
-    return unsafe _computedArgumentHeaderPointer.load(as: Int.self)
+  internal var _computedArgumentSize: ComputedArgumentSize {
+    return unsafe _computedArgumentHeaderPointer.load(as: ComputedArgumentSize.self)
   }
   internal
   var _computedArgumentWitnesses: ComputedArgumentWitnessesPtr {
@@ -1607,16 +1799,20 @@ internal struct RawKeyPathComponent {
     // with its own arguments, we include some additional capture info to
     // be able to map to the original argument context by adjusting the size
     // passed to the witness operations.
-    if unsafe header.isComputedInstantiatedFromExternalWithArguments {
+    if header.isComputedInstantiatedFromExternalWithArguments {
       unsafe base += Header.externalWithArgumentsExtraSize
     }
+
+    // If the argument needed padding to be properly aligned, skip that.
+    unsafe base += _computedArgumentSize.padding
+
     return unsafe base
   }
   internal var _computedMutableArguments: UnsafeMutableRawPointer {
     return unsafe UnsafeMutableRawPointer(mutating: _computedArguments)
   }
   internal var _computedArgumentWitnessSizeAdjustment: Int {
-    if unsafe header.isComputedInstantiatedFromExternalWithArguments {
+    if header.isComputedInstantiatedFromExternalWithArguments {
       return unsafe _computedArguments.load(
         fromByteOffset: 0 &- Header.externalWithArgumentsExtraSize,
         as: Int.self)
@@ -1625,29 +1821,29 @@ internal struct RawKeyPathComponent {
   }
 
   internal var value: KeyPathComponent {
-    switch unsafe header.kind {
+    switch header.kind {
     case .struct:
-      return unsafe .struct(offset: _structOrClassOffset)
+      return .struct(offset: _structOrClassOffset)
     case .class:
-      return unsafe .class(offset: _structOrClassOffset)
+      return .class(offset: _structOrClassOffset)
     case .optionalChain:
-      return unsafe .optionalChain
+      return .optionalChain
     case .optionalForce:
-      return unsafe .optionalForce
+      return .optionalForce
     case .optionalWrap:
-      return unsafe .optionalWrap
+      return .optionalWrap
     case .computed:
-      let isSettable = unsafe header.isComputedSettable
-      let isMutating = unsafe header.isComputedMutating
+      let isSettable = header.isComputedSettable
+      let isMutating = header.isComputedMutating
 
-      let id = unsafe _computedID
-      let accessors = unsafe _computedAccessors
+      let id = _computedID
+      let accessors = _computedAccessors
       // Argument value is unused if there are no arguments.
       let argument: KeyPathComponent.ArgumentRef?
-      if unsafe header.hasComputedArguments {
+      if header.hasComputedArguments {
         unsafe argument = unsafe KeyPathComponent.ArgumentRef(
           data: UnsafeRawBufferPointer(start: _computedArguments,
-                                       count: _computedArgumentSize),
+                                       count: _computedArgumentSize.argumentSize),
           witnesses: _computedArgumentWitnesses,
           witnessSizeAdjustment: _computedArgumentWitnessSizeAdjustment)
       } else {
@@ -1674,7 +1870,7 @@ internal struct RawKeyPathComponent {
   }
 
   internal func destroy() {
-    switch unsafe header.kind {
+    switch header.kind {
     case .struct,
          .class,
          .optionalChain,
@@ -1684,27 +1880,30 @@ internal struct RawKeyPathComponent {
       break
     case .computed:
       // Run destructor, if any
-      if unsafe header.hasComputedArguments,
+      if header.hasComputedArguments,
          let destructor = unsafe _computedArgumentWitnesses.destroy {
         unsafe destructor(_computedMutableArguments,
-                 _computedArgumentSize &- _computedArgumentWitnessSizeAdjustment)
+                 _computedArgumentSize.argumentSize &- _computedArgumentWitnessSizeAdjustment)
       }
     case .external:
       _internalInvariantFailure("should have been instantiated away")
     }
   }
 
-  internal func clone(into buffer: inout UnsafeMutableRawBufferPointer,
-             endOfReferencePrefix: Bool) {
-    var newHeader = unsafe header
-    unsafe newHeader.endOfReferencePrefix = endOfReferencePrefix
+  internal func clone(
+    into buffer: inout UnsafeMutableRawBufferPointer,
+    endOfReferencePrefix: Bool,
+    adjustForAlignment: Bool
+  ) {
+    var newHeader = header
+    newHeader.endOfReferencePrefix = endOfReferencePrefix
 
-    var componentSize = unsafe MemoryLayout<Header>.size
+    var componentSize = MemoryLayout<Header>.size
     unsafe buffer.storeBytes(of: newHeader, as: Header.self)
-    switch unsafe header.kind {
+    switch header.kind {
     case .struct,
          .class:
-      if unsafe header.storedOffsetPayload == Header.outOfLineOffsetPayload {
+      if header.storedOffsetPayload == Header.outOfLineOffsetPayload {
         let overflowOffset = unsafe body.load(as: UInt32.self)
         unsafe buffer.storeBytes(of: overflowOffset, toByteOffset: 4,
                           as: UInt32.self)
@@ -1716,12 +1915,12 @@ internal struct RawKeyPathComponent {
       break
     case .computed:
       // Fields are pointer-aligned after the header
-      unsafe componentSize += Header.pointerAlignmentSkew
+      componentSize += Header.pointerAlignmentSkew
       unsafe buffer.storeBytes(of: _computedIDValue,
                         toByteOffset: componentSize,
                         as: Int.self)
       componentSize += MemoryLayout<Int>.size
-      let accessors = unsafe _computedAccessors
+      let accessors = _computedAccessors
 
       unsafe (buffer.baseAddress.unsafelyUnwrapped + MemoryLayout<Int>.size * 2)
         ._copyAddressDiscriminatedFunctionPointer(
@@ -1730,7 +1929,7 @@ internal struct RawKeyPathComponent {
 
       componentSize += MemoryLayout<Int>.size
 
-      if unsafe header.isComputedSettable {
+      if header.isComputedSettable {
         unsafe (buffer.baseAddress.unsafelyUnwrapped + MemoryLayout<Int>.size * 3)
           ._copyAddressDiscriminatedFunctionPointer(
             from: accessors.setterPtr,
@@ -1740,19 +1939,32 @@ internal struct RawKeyPathComponent {
         componentSize += MemoryLayout<Int>.size
       }
 
-      if unsafe header.hasComputedArguments {
+      if header.hasComputedArguments {
         let arguments = unsafe _computedArguments
-        let argumentSize = unsafe _computedArgumentSize
-        unsafe buffer.storeBytes(of: argumentSize,
-                          toByteOffset: componentSize,
-                          as: Int.self)
+        let argumentSize = _computedArgumentSize
+        // Remember the argument size location, we may need to adjust the value
+        // for alignment.
+        let argumentSizePtr = unsafe buffer.baseAddress._unsafelyUnwrappedUnchecked + componentSize
+
+        // If we don't need to adjust for alignment, then the current argument
+        // size is correct. If alignment is 0, then the arguments had equal
+        // to or less than alignment to the platform's word alignment.
+        if !adjustForAlignment || argumentSize.alignment == 0 {
+          unsafe buffer.storeBytes(
+            of: argumentSize,
+            toByteOffset: componentSize,
+            as: ComputedArgumentSize.self
+          )
+        }
+
         componentSize += MemoryLayout<Int>.size
+
         unsafe buffer.storeBytes(of: _computedArgumentWitnesses,
                           toByteOffset: componentSize,
                           as: ComputedArgumentWitnessesPtr.self)
         componentSize += MemoryLayout<Int>.size
 
-        if unsafe header.isComputedInstantiatedFromExternalWithArguments {
+        if header.isComputedInstantiatedFromExternalWithArguments {
           // Include the extra matter for components instantiated from
           // external property descriptors with arguments.
           unsafe buffer.storeBytes(of: _computedArgumentWitnessSizeAdjustment,
@@ -1760,14 +1972,57 @@ internal struct RawKeyPathComponent {
                             as: Int.self)
           componentSize += MemoryLayout<Int>.size
         }
-        let adjustedSize = unsafe argumentSize - _computedArgumentWitnessSizeAdjustment
-        let argumentDest =
+
+        let adjustedSize = argumentSize.argumentSize &-
+                           _computedArgumentWitnessSizeAdjustment
+        var argumentDest =
           unsafe buffer.baseAddress.unsafelyUnwrapped + componentSize
+
+        // If we're not adjusting for alignment, but we had existing padding, we
+        // need to mimic the exact padding.
+        if !adjustForAlignment, argumentSize.padding != 0 {
+          unsafe argumentDest += argumentSize.padding
+          componentSize &+= argumentSize.padding
+        }
+
+        // We've been asked to adjust for alignment and the original argument
+        // was overaligned. Check for misalignment at our current destination.
+        if adjustForAlignment, argumentSize.alignment != 0 {
+          var newArgumentSize = ComputedArgumentSize(argumentSize.argumentSize)
+          let argumentAlignmentMask = argumentSize.alignment &- 1
+          let misaligned = Int(bitPattern: argumentDest) & argumentAlignmentMask
+
+          if misaligned == 0 {
+            newArgumentSize.padding = 0
+            newArgumentSize.alignment = argumentSize.alignment
+
+            unsafe argumentSizePtr.storeBytes(
+              of: newArgumentSize,
+              as: ComputedArgumentSize.self
+            )
+          } else {
+            // Otherwise, this is still misaligned and we need to calculate
+            // how much padding we need.
+            newArgumentSize.padding = argumentSize.alignment &- misaligned
+            newArgumentSize.alignment = argumentSize.alignment
+
+            unsafe argumentSizePtr.storeBytes(
+              of: newArgumentSize,
+              as: ComputedArgumentSize.self
+            )
+
+            // Push the buffer past the padding.
+            unsafe argumentDest += newArgumentSize.padding
+            componentSize += newArgumentSize.padding
+          }
+        }
+
         unsafe _computedArgumentWitnesses.copy(
           arguments,
           argumentDest,
           adjustedSize)
-        if unsafe header.isComputedInstantiatedFromExternalWithArguments {
+
+        if header.isComputedInstantiatedFromExternalWithArguments {
           // The extra information for external property descriptor arguments
           // can always be memcpy'd.
           unsafe _memcpy(dest: argumentDest + adjustedSize,
@@ -1775,7 +2030,7 @@ internal struct RawKeyPathComponent {
                   size: UInt(_computedArgumentWitnessSizeAdjustment))
         }
 
-        componentSize += argumentSize
+        componentSize += argumentSize.argumentSize
       }
 
     case .external:
@@ -1793,7 +2048,7 @@ internal struct RawKeyPathComponent {
     _ isBreak: inout Bool,
     pointer: UnsafeMutablePointer<NewValue>
   ) {
-    switch unsafe value {
+    switch value {
     case .struct(let offset):
       unsafe _withUnprotectedUnsafeBytes(of: base) {
         let p = unsafe $0.baseAddress._unsafelyUnwrappedUnchecked + offset
@@ -1899,7 +2154,7 @@ internal struct RawKeyPathComponent {
     isRoot: Bool,
     keepAlive: inout AnyObject?
   ) -> UnsafeRawPointer {
-    switch unsafe value {
+    switch value {
     case .struct(let offset):
       return unsafe base.advanced(by: offset)
     case .class(let offset):
@@ -2012,9 +2267,9 @@ internal struct KeyPathBuffer {
     unsafe data = unsafe UnsafeRawBufferPointer(
       start: base + MemoryLayout<Int>.size,
       count: header.size)
-    unsafe trivial = unsafe header.trivial
-    unsafe hasReferencePrefix = unsafe header.hasReferencePrefix
-    unsafe isSingleComponent = unsafe header.isSingleComponent
+    unsafe trivial = header.trivial
+    unsafe hasReferencePrefix = header.hasReferencePrefix
+    unsafe isSingleComponent = header.isSingleComponent
   }
 
   internal init(partialData: UnsafeRawBufferPointer,
@@ -2084,8 +2339,8 @@ internal struct KeyPathBuffer {
       hasReferencePrefix: Bool,
       isSingleComponent: Bool
     ) {
-      unsafe _internalInvariant(size <= Int(Header.sizeMask), "key path too big")
-      unsafe _value = unsafe UInt32(size)
+      _internalInvariant(size <= Int(Header.sizeMask), "key path too big")
+      _value = UInt32(size)
         | (trivial ? Header.trivialFlag : 0)
         | (hasReferencePrefix ? Header.hasReferencePrefixFlag : 0)
         | (isSingleComponent ? Header.isSingleComponentFlag : 0)
@@ -2107,30 +2362,30 @@ internal struct KeyPathBuffer {
       return _SwiftKeyPathBufferHeader_IsSingleComponentFlag
     }
 
-    internal var size: Int { return unsafe Int(_value & Header.sizeMask) }
-    internal var trivial: Bool { return unsafe _value & Header.trivialFlag != 0 }
+    internal var size: Int { return Int(_value & Header.sizeMask) }
+    internal var trivial: Bool { return _value & Header.trivialFlag != 0 }
     internal var hasReferencePrefix: Bool {
       get {
-        return unsafe _value & Header.hasReferencePrefixFlag != 0
+        return _value & Header.hasReferencePrefixFlag != 0
       }
       set {
         if newValue {
-          unsafe _value |= Header.hasReferencePrefixFlag
+          _value |= Header.hasReferencePrefixFlag
         } else {
-          unsafe _value &= ~Header.hasReferencePrefixFlag
+          _value &= ~Header.hasReferencePrefixFlag
         }
       }
     }
     internal var isSingleComponent: Bool {
       get {
-        return unsafe _value & Header.isSingleComponentFlag != 0
+        return _value & Header.isSingleComponentFlag != 0
       }
 
       set {
         if newValue {
-          unsafe _value |= Header.isSingleComponentFlag
+          _value |= Header.isSingleComponentFlag
         } else {
-          unsafe _value &= ~Header.isSingleComponentFlag
+          _value &= ~Header.isSingleComponentFlag
         }
       }
     }
@@ -2138,11 +2393,11 @@ internal struct KeyPathBuffer {
     // In a key path pattern, the "trivial" flag is used to indicate
     // "instantiable in-line"
     internal var instantiableInLine: Bool {
-      return unsafe trivial
+      return trivial
     }
 
     internal func validateReservedBits() {
-      unsafe _precondition(_value & Header.reservedMask == 0,
+      _precondition(_value & Header.reservedMask == 0,
                     "Reserved bits set to an unexpected bit pattern")
     }
   }
@@ -2154,15 +2409,16 @@ internal struct KeyPathBuffer {
     var bufferToDestroy = unsafe self
     while true {
       let (component, type) = unsafe bufferToDestroy.next()
-      unsafe component.destroy()
+      component.destroy()
       guard let _ = type else { break }
     }
   }
   
+  @inline(never)
   internal mutating func next() -> (RawKeyPathComponent, Any.Type?) {
     let header = unsafe _pop(from: &data, as: RawKeyPathComponent.Header.self)
     // Track if this is the last component of the reference prefix.
-    if unsafe header.endOfReferencePrefix {
+    if header.endOfReferencePrefix {
       unsafe _internalInvariant(self.hasReferencePrefix,
                    "beginMutation marker in non-reference-writable key path?")
       unsafe self.hasReferencePrefix = false
@@ -2170,7 +2426,7 @@ internal struct KeyPathBuffer {
     
     var component = unsafe RawKeyPathComponent(header: header, body: data)
     // Shrinkwrap the component buffer size.
-    let size = unsafe component.bodySize
+    let size = component.bodySize
     unsafe component.body = unsafe UnsafeRawBufferPointer(start: component.body.baseAddress,
                                             count: size)
     _ = unsafe _pop(from: &data, as: Int8.self, count: size)
@@ -2182,7 +2438,7 @@ internal struct KeyPathBuffer {
     } else {
       nextType = unsafe _pop(from: &data, as: Any.Type.self)
     }
-    return unsafe (component, nextType)
+    return (component, nextType)
   }
 }
 
@@ -2609,6 +2865,101 @@ internal func _tryToAppendKeyPaths<Result: AnyKeyPath>(
   return _openExistential(rootRoot, do: open)
 }
 
+@_unavailableInEmbedded
+internal func calculateAppendedKeyPathSize(
+  _ root: AnyKeyPath,
+  _ leaf: AnyKeyPath,
+  _ rootBuffer: KeyPathBuffer,
+  _ leafBuffer: KeyPathBuffer
+) -> (Int, Int, Int, Int, Int, Int) {
+  var result = MemoryLayout<Int>.size // Header size (padding if needed)
+  var resultWithObjectHeaderAndKVC: Int {
+    result &+ MemoryLayout<Int>.size &* 3
+  }
+
+  // Result buffer has room for both key paths' components, plus the
+  // header, plus space for the middle type.
+  // Align up the root so that we can put the component type after it.
+  result &+= unsafe MemoryLayout<Int>._roundingUpToAlignment(rootBuffer.data.count)
+  result &+= MemoryLayout<Int>.size // Middle type
+
+  var leafIter = unsafe leafBuffer
+  while true {
+    let (component, nextType) = unsafe leafIter.next()
+    let isLast = nextType == nil
+
+    result &+= MemoryLayout<RawKeyPathComponent.Header>.size
+
+    if component.header.kind == .computed,
+       component.header.hasComputedArguments,
+       component._computedArgumentSize.alignment != 0 {
+      result = MemoryLayout<Int>._roundingUpToAlignment(result)
+
+      // Id and getter
+      result &+= MemoryLayout<Int>.size &* 2
+
+      if component.header.isComputedSettable {
+        result &+= MemoryLayout<Int>.size
+      }
+
+      // Argument size and witness table
+      result &+= MemoryLayout<Int>.size &* 2
+
+      // If we also have external arguments, we need to store the size of the
+      // local arguments so we can find the external component arguments.
+      if component.header.isComputedInstantiatedFromExternalWithArguments {
+        result &+= RawKeyPathComponent.Header.externalWithArgumentsExtraSize
+      }
+
+      let alignmentMask = component._computedArgumentSize.alignment &- 1
+      let misaligned = resultWithObjectHeaderAndKVC & alignmentMask
+
+      if misaligned != 0 {
+        result &+= component._computedArgumentSize.alignment &- misaligned
+      }
+
+      result &+= component._computedArgumentSize.argumentSize
+    } else {
+      result &+= component.bodySize
+    }
+
+    if isLast {
+      break
+    }
+  }
+
+  // Size of just our components is equal to root + middle + leaf (get rid of
+  // the header and any padding needed).
+  let componentSize = result &- MemoryLayout<Int>.size
+
+  // The first member after the components is the maxSize of the keypath.
+  result = MemoryLayout<Int>._roundingUpToAlignment(result)
+  result &+= MemoryLayout<Int>.size
+
+  // Reserve room for the appended KVC string, if both key paths are
+  // KVC-compatible.
+  let appendedKVCLength: Int, rootKVCLength: Int, leafKVCLength: Int
+
+  if root.getOffsetFromStorage() == nil, leaf.getOffsetFromStorage() == nil,
+    let rootPtr = unsafe root._kvcKeyPathStringPtr,
+    let leafPtr = unsafe leaf._kvcKeyPathStringPtr {
+    rootKVCLength = unsafe Int(_swift_stdlib_strlen(rootPtr))
+    leafKVCLength = unsafe Int(_swift_stdlib_strlen(leafPtr))
+    // root + "." + leaf
+    appendedKVCLength = rootKVCLength &+ 1 &+ leafKVCLength &+ 1
+  } else {
+    rootKVCLength = 0
+    leafKVCLength = 0
+    appendedKVCLength = 0
+  }
+
+  // Immediately following is the tail-allocated space for the KVC string.
+  let totalResultSize = MemoryLayout<Int32>._roundingUpToAlignment(result &+ appendedKVCLength)
+
+  return (result, totalResultSize, componentSize, appendedKVCLength,
+          rootKVCLength, leafKVCLength)
+}
+
 @usableFromInline
 @_unavailableInEmbedded
 internal func _appendingKeyPaths<
@@ -2633,44 +2984,19 @@ internal func _appendingKeyPaths<
         return unsafe unsafeDowncast(leaf, to: Result.self)
       }
 
-      // Reserve room for the appended KVC string, if both key paths are
-      // KVC-compatible.
-      let appendedKVCLength: Int, rootKVCLength: Int, leafKVCLength: Int
-
-      if root.getOffsetFromStorage() == nil, leaf.getOffsetFromStorage() == nil,
-        let rootPtr = unsafe root._kvcKeyPathStringPtr,
-        let leafPtr = unsafe leaf._kvcKeyPathStringPtr {
-        rootKVCLength = unsafe Int(_swift_stdlib_strlen(rootPtr))
-        leafKVCLength = unsafe Int(_swift_stdlib_strlen(leafPtr))
-        // root + "." + leaf
-        appendedKVCLength = rootKVCLength + 1 + leafKVCLength + 1
-      } else {
-        rootKVCLength = 0
-        leafKVCLength = 0
-        appendedKVCLength = 0
-      }
-
-      // Result buffer has room for both key paths' components, plus the
-      // header, plus space for the middle type.
-      // Align up the root so that we can put the component type after it.
-      let rootSize = unsafe MemoryLayout<Int>._roundingUpToAlignment(rootBuffer.data.count)
-      var resultSize = unsafe rootSize + // Root component size
-                       leafBuffer.data.count + // Leaf component size
-                       MemoryLayout<Int>.size // Middle type
-
-      // Size of just our components is equal to root + leaf + middle
-      let componentSize = resultSize
-
-      resultSize += MemoryLayout<Int>.size // Header size (padding if needed)
-
-      // The first member after the components is the maxSize of the keypath.
-      resultSize = MemoryLayout<Int>._roundingUpToAlignment(resultSize)
-      resultSize += MemoryLayout<Int>.size
-
-      // Immediately following is the tail-allocated space for the KVC string.
-      let totalResultSize = MemoryLayout<Int32>
-        ._roundingUpToAlignment(resultSize + appendedKVCLength)
-
+      let (
+        resultSize,
+        totalResultSize,
+        componentSize,
+        appendedKVCLength,
+        rootKVCLength,
+        leafKVCLength
+      ) = unsafe calculateAppendedKeyPathSize(
+        root,
+        leaf,
+        rootBuffer,
+        leafBuffer
+      )
       var kvcStringBuffer: UnsafeMutableRawPointer? = nil
 
       let result = unsafe resultTy._create(capacityInBytes: totalResultSize) {
@@ -2716,12 +3042,17 @@ internal func _appendingKeyPaths<
           } else if isLast && leafIsReferenceWritable {
             endOfReferencePrefix = true
           } else {
-            endOfReferencePrefix = unsafe component.header.endOfReferencePrefix
+            endOfReferencePrefix = component.header.endOfReferencePrefix
           }
           
           unsafe component.clone(
             into: &destBuilder.buffer,
-            endOfReferencePrefix: endOfReferencePrefix)
+            endOfReferencePrefix: endOfReferencePrefix,
+
+            // Root components don't need to adjust for alignment because the
+            // components should appear at the same offset as the root keypath.
+            adjustForAlignment: false
+          )
           // Insert our endpoint type between the root and leaf components.
           if let type = type {
             unsafe destBuilder.push(type)
@@ -2739,7 +3070,13 @@ internal func _appendingKeyPaths<
 
           unsafe component.clone(
             into: &destBuilder.buffer,
-            endOfReferencePrefix: component.header.endOfReferencePrefix)
+            endOfReferencePrefix: component.header.endOfReferencePrefix,
+
+            // Leaf components, however, can appear at actual aligned spots that
+            // they couldn't before. Adjust computed arguments for this
+            // potential.
+            adjustForAlignment: true
+          )
 
           if let type = type {
             unsafe destBuilder.push(type)
@@ -2835,7 +3172,7 @@ public func _swift_getKeyPath(pattern: UnsafeMutableRawPointer,
 
   let bufferHeader = unsafe patternPtr.load(fromByteOffset: keyPathPatternHeaderSize,
                                      as: KeyPathBuffer.Header.self)
-  unsafe bufferHeader.validateReservedBits()
+  bufferHeader.validateReservedBits()
 
   // If the first word is nonzero, it relative-references a cache variable
   // we can use to reference a single shared instantiation of this key path.
@@ -2868,7 +3205,7 @@ public func _swift_getKeyPath(pattern: UnsafeMutableRawPointer,
   // Instantiate a new key path object modeled on the pattern.
   // Do a pass to determine the class of the key path we'll be instantiating
   // and how much space we'll need for it.
-  let (keyPathClass, rootType, size, sizeWithMaxSize, _)
+  let (keyPathClass, rootType, size, sizeWithMaxSize)
     = unsafe _getKeyPathClassAndInstanceSizeFromPattern(patternPtr, arguments)
 
   var pureStructOffset: UInt32? = nil
@@ -3119,7 +3456,7 @@ internal func _resolveRelativeIndirectableAddress(_ base: UnsafeRawPointer,
 internal func _resolveCompactFunctionPointer(_ base: UnsafeRawPointer, _ offset: Int32)
     -> UnsafeRawPointer {
 #if SWIFT_COMPACT_ABSOLUTE_FUNCTION_POINTER
-  return UnsafeRawPointer(bitPattern: Int(offset))._unsafelyUnwrappedUnchecked
+  return unsafe UnsafeRawPointer(bitPattern: Int(offset))._unsafelyUnwrappedUnchecked
 #else
   return unsafe _resolveRelativeAddress(base, offset)
 #endif
@@ -3158,14 +3495,14 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
     // header word, or else be stored out-of-line, or need instantiation of some
     // kind.
     let offset: KeyPathPatternStoredOffset
-    switch unsafe header.storedOffsetPayload {
-    case unsafe RawKeyPathComponent.Header.outOfLineOffsetPayload:
+    switch header.storedOffsetPayload {
+    case RawKeyPathComponent.Header.outOfLineOffsetPayload:
       unsafe offset = unsafe .outOfLine(_pop(from: &componentBuffer,
                                as: UInt32.self))
-    case unsafe RawKeyPathComponent.Header.unresolvedFieldOffsetPayload:
+    case RawKeyPathComponent.Header.unresolvedFieldOffsetPayload:
       unsafe offset = unsafe .unresolvedFieldOffset(_pop(from: &componentBuffer,
                                            as: UInt32.self))
-    case unsafe RawKeyPathComponent.Header.unresolvedIndirectOffsetPayload:
+    case RawKeyPathComponent.Header.unresolvedIndirectOffsetPayload:
       let base = unsafe componentBuffer.baseAddress._unsafelyUnwrappedUnchecked
       let relativeOffset = unsafe _pop(from: &componentBuffer,
                                 as: Int32.self)
@@ -3175,7 +3512,7 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
     default:
       unsafe offset = unsafe .inline(header.storedOffsetPayload)
     }
-    let kind: KeyPathStructOrClass = unsafe header.kind == .struct 
+    let kind: KeyPathStructOrClass = header.kind == .struct
       ? .struct : .class
     unsafe walker.visitStoredComponent(kind: kind,
                                 mutable: header.isStoredMutable,
@@ -3194,7 +3531,7 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
     let getterRef = unsafe _pop(from: &componentBuffer, as: Int32.self)
     let getter = unsafe _resolveCompactFunctionPointer(getterBase, getterRef)
     let setter: UnsafeRawPointer?
-    if unsafe header.isComputedSettable {
+    if header.isComputedSettable {
       let setterBase = unsafe componentBuffer.baseAddress._unsafelyUnwrappedUnchecked
       let setterRef = unsafe _pop(from: &componentBuffer, as: Int32.self)
       unsafe setter = unsafe _resolveCompactFunctionPointer(setterBase, setterRef)
@@ -3208,7 +3545,7 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
   func popComputedArguments(header: RawKeyPathComponent.Header,
                             componentBuffer: inout UnsafeRawBufferPointer)
       -> KeyPathPatternComputedArguments? {
-    if unsafe header.hasComputedArguments {
+    if header.hasComputedArguments {
       let getLayoutBase = unsafe componentBuffer.baseAddress._unsafelyUnwrappedUnchecked
       let getLayoutRef = unsafe _pop(from: &componentBuffer, as: Int32.self)
       let getLayoutRaw = unsafe _resolveCompactFunctionPointer(getLayoutBase, getLayoutRef)
@@ -3222,7 +3559,7 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
       let witnessesRef = unsafe _pop(from: &componentBuffer, as: Int32.self)
       let witnesses: UnsafeRawPointer
       if witnessesRef == 0 {
-        unsafe witnesses = unsafe __swift_keyPathGenericWitnessTable_addr()
+        unsafe witnesses = __swift_keyPathGenericWitnessTable_addr()
       } else {
         unsafe witnesses = unsafe _resolveRelativeAddress(witnessesBase, witnessesRef)
       }
@@ -3264,11 +3601,11 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
 
     _internalInvariant({
       bufferSizeBefore = buffer.count
-      expectedPop = unsafe header.patternComponentBodySize
+      expectedPop = header.patternComponentBodySize
       return true
     }())
 
-    switch unsafe header.kind {
+    switch header.kind {
     case .class, .struct:
       unsafe visitStored(header: header, componentBuffer: &buffer)
     case .computed:
@@ -3299,7 +3636,7 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
     case .external:
       // Look at the external property descriptor to see if we should take it
       // over the component given in the pattern.
-      let genericParamCount = unsafe Int(header.payload)
+      let genericParamCount = Int(header.payload)
       let descriptorBase = unsafe buffer.baseAddress._unsafelyUnwrappedUnchecked
       let descriptorOffset = unsafe _pop(from: &buffer,
                                   as: Int32.self)
@@ -3307,8 +3644,8 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
         unsafe _resolveRelativeIndirectableAddress(descriptorBase, descriptorOffset)
       let descriptorHeader: RawKeyPathComponent.Header
       if unsafe descriptor != UnsafeRawPointer(bitPattern: 0) {
-        unsafe descriptorHeader = unsafe descriptor.load(as: RawKeyPathComponent.Header.self)
-        if unsafe descriptorHeader.isTrivialPropertyDescriptor {
+        descriptorHeader = unsafe descriptor.load(as: RawKeyPathComponent.Header.self)
+        if descriptorHeader.isTrivialPropertyDescriptor {
           // If the descriptor is trivial, then use the local candidate.
           // Skip the external generic parameter accessors to get to it.
           _ = unsafe _pop(from: &buffer, as: Int32.self, count: genericParamCount)
@@ -3329,18 +3666,18 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
       // a computed property.
       let localCandidateHeader = unsafe _pop(from: &buffer,
                                       as: RawKeyPathComponent.Header.self)
-      let localCandidateSize = unsafe localCandidateHeader.patternComponentBodySize
+      let localCandidateSize = localCandidateHeader.patternComponentBodySize
       _internalInvariant({
         expectedPop += localCandidateSize + 4
         return true
       }())
 
-      let descriptorSize = unsafe descriptorHeader.propertyDescriptorBodySize
+      let descriptorSize = descriptorHeader.propertyDescriptorBodySize
       var descriptorBuffer = unsafe UnsafeRawBufferPointer(start: descriptor + 4,
                                                     count: descriptorSize)
 
       // Look at what kind of component the external property has.
-      switch unsafe descriptorHeader.kind {
+      switch descriptorHeader.kind {
       case .struct, .class:
         // A stored component. We can instantiate it
         // without help from the local candidate.
@@ -3358,7 +3695,7 @@ internal func _walkKeyPathPattern<W: KeyPathPatternVisitor>(
         // Get the arguments from the external descriptor and/or local candidate
         // component.
         let arguments: KeyPathPatternComputedArguments?
-        if unsafe localCandidateHeader.kind == .computed
+        if localCandidateHeader.kind == .computed
             && localCandidateHeader.hasComputedArguments {
           // If both have arguments, then we have to build a bit of a chimera.
           // The canonical identity and accessors come from the descriptor,
@@ -3430,6 +3767,9 @@ internal struct GetKeyPathClassAndInstanceSizeFromPattern
   // start with one word for the header
   var size: Int = MemoryLayout<Int>.size
   var sizeWithMaxSize: Int = 0
+  var sizeWithObjectHeaderAndKvc: Int {
+    unsafe size &+ MemoryLayout<Int>.size &* 3
+  }
 
   var capability: KeyPathKind = .value
   var didChain: Bool = false
@@ -3526,46 +3866,50 @@ internal struct GetKeyPathClassAndInstanceSizeFromPattern
     if settable {
       unsafe size += MemoryLayout<Int>.size
     }
-    
-    // ...and the arguments, if any.
-    let argumentHeaderSize = MemoryLayout<Int>.size * 2
-    switch unsafe (arguments, externalArgs) {
-    case (nil, nil):
-      break
-    case (let arguments?, nil):
-      unsafe size += argumentHeaderSize
-      // If we have arguments, calculate how much space they need by invoking
-      // the layout function.
-      let (addedSize, addedAlignmentMask) = unsafe arguments.getLayout(patternArgs)
-      // TODO: Handle over-aligned values
-      _internalInvariant(addedAlignmentMask < MemoryLayout<Int>.alignment,
-                   "overaligned computed property element not supported")
-      unsafe size += addedSize
-    
-    case (let arguments?, let externalArgs?):
-      // If we're referencing an external declaration, and it takes captured
-      // arguments, then we have to build a bit of a chimera. The canonical
-      // identity and accessors come from the descriptor, but the argument
-      // handling is still as described in the local candidate.
-      unsafe size += argumentHeaderSize
-      let (addedSize, addedAlignmentMask) = unsafe arguments.getLayout(patternArgs)
-      // TODO: Handle over-aligned values
-      _internalInvariant(addedAlignmentMask < MemoryLayout<Int>.alignment,
-                   "overaligned computed property element not supported")
-      unsafe size += addedSize
-      // We also need to store the size of the local arguments so we can
-      // find the external component arguments.
+
+    // Handle local arguments.
+    if let arguments = unsafe arguments {
+      // Argument size and witnesses ptr.
+      unsafe size &+= MemoryLayout<Int>.size &* 2
+
+      // If we also have external arguments, we need to store the size of the
+      // local arguments so we can find the external component arguments.
+      if unsafe externalArgs != nil {
+        unsafe size &+= RawKeyPathComponent.Header.externalWithArgumentsExtraSize
+      }
+
+      let (typeSize, typeAlignMask) = unsafe arguments.getLayout(patternArgs)
+
+      // We are known to be pointer aligned at this point in the KeyPath buffer.
+      // However, for types who have an alignment large than pointers, we need
+      // to determine if the current position is suitable for the argument, or
+      // if we need to add padding bytes to align ourselves.
+      //
+      // Note: We need to account for the object header and kvc pointer because
+      // it's an odd number of words which will affect whether the size visitor
+      // determines if we need padding. It would cause out of sync answers when
+      // going to actually instantiate the buffer.
+      let misaligned = unsafe sizeWithObjectHeaderAndKvc & typeAlignMask
+
+      if misaligned != 0 {
+        // We were misaligned, add the padding to the total size of the keypath
+        // buffer.
+        let typeAlign = typeAlignMask &+ 1
+        unsafe size &+= typeAlign &- misaligned
+      }
+
+      unsafe size &+= typeSize
       unsafe roundUpToPointerAlignment()
-      unsafe size += RawKeyPathComponent.Header.externalWithArgumentsExtraSize
-      unsafe size += MemoryLayout<Int>.size * externalArgs.count
+    }
+
+    // Handle external arguments.
+    if let externalArgs = unsafe externalArgs {
+      // Argument size and witnesses ptr if we didn't have local arguments.
+      if unsafe arguments == nil {
+        unsafe size &+= MemoryLayout<Int>.size &* 2
+      }
 
-    case (nil, let externalArgs?):
-      // If we're instantiating an external property with a local
-      // candidate that has no arguments, then things are a little
-      // easier. We only need to instantiate the generic
-      // arguments for the external component's accessors.
-      unsafe size += argumentHeaderSize
-      unsafe size += MemoryLayout<Int>.size * externalArgs.count
+      unsafe size &+= MemoryLayout<Int>.size &* externalArgs.count
     }
   }
 
@@ -3598,8 +3942,7 @@ internal struct GetKeyPathClassAndInstanceSizeFromPattern
   }
 
   mutating func finish() {
-    unsafe sizeWithMaxSize = unsafe size
-    unsafe sizeWithMaxSize = unsafe MemoryLayout<Int>._roundingUpToAlignment(sizeWithMaxSize)
+    unsafe sizeWithMaxSize = unsafe MemoryLayout<Int>._roundingUpToAlignment(size)
     unsafe sizeWithMaxSize &+= MemoryLayout<Int>.size
   }
 }
@@ -3612,8 +3955,7 @@ internal func _getKeyPathClassAndInstanceSizeFromPattern(
   keyPathClass: AnyKeyPath.Type,
   rootType: Any.Type,
   size: Int,
-  sizeWithMaxSize: Int,
-  alignmentMask: Int
+  sizeWithMaxSize: Int
 ) {
   var walker = unsafe GetKeyPathClassAndInstanceSizeFromPattern(patternArgs: arguments)
   unsafe _walkKeyPathPattern(pattern, walker: &walker)
@@ -3639,12 +3981,12 @@ internal func _getKeyPathClassAndInstanceSizeFromPattern(
   }
   let classTy = unsafe _openExistential(walker.root!, do: openRoot)
 
-  return unsafe (keyPathClass: classTy,
-          rootType: walker.root!,
-          size: walker.size,
-          sizeWithMaxSize: walker.sizeWithMaxSize,
-          // FIXME: Handle overalignment
-          alignmentMask: MemoryLayout<Int>._alignmentMask)
+  return unsafe (
+    keyPathClass: classTy,
+    rootType: walker.root!,
+    size: walker.size,
+    sizeWithMaxSize: walker.sizeWithMaxSize
+  )
 }
 
 internal func _getTypeSize<Type>(_: Type.Type) -> Int {
@@ -3762,7 +4104,7 @@ internal struct InstantiateKeyPathBuffer: KeyPathPatternVisitor {
       // Resolve the offset.
       switch unsafe offset {
       case .inline(let value):
-        let header = unsafe RawKeyPathComponent.Header(stored: kind,
+        let header = RawKeyPathComponent.Header(stored: kind,
                                                 mutable: mutable,
                                                 inlineOffset: value)
         unsafe pushDest(header)
@@ -3773,7 +4115,7 @@ internal struct InstantiateKeyPathBuffer: KeyPathPatternVisitor {
              break
         }
       case .outOfLine(let offset):
-        let header = unsafe RawKeyPathComponent.Header(storedWithOutOfLineOffset: kind,
+        let header = RawKeyPathComponent.Header(storedWithOutOfLineOffset: kind,
                                                 mutable: mutable)
         unsafe pushDest(header)
         unsafe pushDest(offset)
@@ -3792,7 +4134,7 @@ internal struct InstantiateKeyPathBuffer: KeyPathPatternVisitor {
           unsafe structOffset += offset
         }
 
-        let header = unsafe RawKeyPathComponent.Header(storedWithOutOfLineOffset: kind,
+        let header = RawKeyPathComponent.Header(storedWithOutOfLineOffset: kind,
                                                 mutable: mutable)
         unsafe pushDest(header)
         unsafe pushDest(offset)
@@ -3801,7 +4143,7 @@ internal struct InstantiateKeyPathBuffer: KeyPathPatternVisitor {
         // pointer.
         unsafe _internalInvariant(pointerToOffset.pointee <= UInt32.max)
         let offset = unsafe UInt32(truncatingIfNeeded: pointerToOffset.pointee)
-        let header = unsafe RawKeyPathComponent.Header(storedWithOutOfLineOffset: kind,
+        let header = RawKeyPathComponent.Header(storedWithOutOfLineOffset: kind,
                                                 mutable: mutable)
         unsafe pushDest(header)
         unsafe pushDest(offset)
@@ -3890,22 +4232,12 @@ internal struct InstantiateKeyPathBuffer: KeyPathPatternVisitor {
     }
 
     if let arguments = unsafe arguments {
-      // Instantiate the arguments.
-      let (baseSize, alignmentMask) = unsafe arguments.getLayout(patternArgs)
-      _internalInvariant(alignmentMask < MemoryLayout<Int>.alignment,
-                   "overaligned computed arguments not implemented yet")
-
-      // The real buffer stride will be rounded up to alignment.
-      var totalSize = (baseSize + alignmentMask) & ~alignmentMask
-
-      // If an external property descriptor also has arguments, they'll be
-      // added to the end with pointer alignment.
-      if let externalArgs = unsafe externalArgs {
-        totalSize = MemoryLayout<Int>._roundingUpToAlignment(totalSize)
-        totalSize += MemoryLayout<Int>.size * externalArgs.count
-      }
+      // Record a placeholder for the total size of the arguments. We need to
+      // check after pushing preliminary data if the resulting argument will
+      // require padding bytes to be properly aligned.
+      let totalSizeAddress = unsafe destData.baseAddress._unsafelyUnwrappedUnchecked
+      unsafe pushDest(ComputedArgumentSize(0))
 
-      unsafe pushDest(totalSize)
       unsafe pushDest(arguments.witnesses)
 
       // A nonnull destructor in the witnesses file indicates the instantiated
@@ -3921,15 +4253,60 @@ internal struct InstantiateKeyPathBuffer: KeyPathPatternVisitor {
         unsafe pushDest(externalArgs.count * MemoryLayout<Int>.size)
       }
 
+      let (typeSize, typeAlignMask) = unsafe arguments.getLayout(patternArgs)
+      var argumentSize = typeSize
+
+      // If an external property descriptor also has arguments, they'll be
+      // added to the end with pointer alignment.
+      if let externalArgs = unsafe externalArgs {
+        argumentSize = MemoryLayout<Int>._roundingUpToAlignment(argumentSize)
+        argumentSize += MemoryLayout<Int>.size * externalArgs.count
+      }
+
+      // The argument total size contains the padding and alignment bits
+      // required for the argument in the top 1/3 bits, so ensure the size of
+      // the argument buffer is small enough to account for that.
+      _precondition(
+        argumentSize <= ComputedArgumentSize.sizeMask,
+        "keypath arguments are too large"
+      )
+
+      var totalSize = ComputedArgumentSize(argumentSize)
+      let typeAlignment = typeAlignMask &+ 1
+      totalSize.alignment = typeAlignment
+
+      // We are known to be pointer aligned at this point in the KeyPath buffer.
+      // However, for types who have an alignment large than pointers, we need
+      // to determine if the current position is suitable for the argument, or
+      // if we need to add padding bytes to align ourselves.
+      let argumentAddress = unsafe destData.baseAddress._unsafelyUnwrappedUnchecked
+      let misaligned = Int(bitPattern: argumentAddress) & typeAlignMask
+
+      if misaligned != 0 {
+        totalSize.padding = typeAlignment &- misaligned
+
+        // Go ahead and append the padding.
+        for _ in 0 ..< totalSize.padding {
+          unsafe pushDest(UInt8(0))
+        }
+      }
+
+      // Ok, we've fully calculated totalSize, go ahead and update the
+      // placeholder.
+      unsafe totalSizeAddress.storeBytes(
+        of: totalSize,
+        as: ComputedArgumentSize.self
+      )
+
       // Initialize the local candidate arguments here.
-      unsafe _internalInvariant(Int(bitPattern: destData.baseAddress) & alignmentMask == 0,
+      unsafe _internalInvariant(Int(bitPattern: destData.baseAddress) & typeAlignMask == 0,
                    "argument destination not aligned")
       unsafe arguments.initializer(patternArgs,
                             destData.baseAddress._unsafelyUnwrappedUnchecked)
 
       unsafe destData = unsafe UnsafeMutableRawBufferPointer(
-        start: destData.baseAddress._unsafelyUnwrappedUnchecked + baseSize,
-        count: destData.count - baseSize)
+        start: destData.baseAddress._unsafelyUnwrappedUnchecked + typeSize,
+        count: destData.count - typeSize)
     }
     
     if let externalArgs = unsafe externalArgs {
@@ -3960,19 +4337,19 @@ internal struct InstantiateKeyPathBuffer: KeyPathPatternVisitor {
   mutating func visitOptionalChainComponent() {
     unsafe isPureStruct.append(false)
     let _ = unsafe updatePreviousComponentAddr()
-    let header = unsafe RawKeyPathComponent.Header(optionalChain: ())
+    let header = RawKeyPathComponent.Header(optionalChain: ())
     unsafe pushDest(header)
   }
   mutating func visitOptionalWrapComponent() {
     unsafe isPureStruct.append(false)
     let _ = unsafe updatePreviousComponentAddr()
-    let header = unsafe RawKeyPathComponent.Header(optionalWrap: ())
+    let header = RawKeyPathComponent.Header(optionalWrap: ())
     unsafe pushDest(header)
   }
   mutating func visitOptionalForceComponent() {
     unsafe isPureStruct.append(false)
     let _ = unsafe updatePreviousComponentAddr()
-    let header = unsafe RawKeyPathComponent.Header(optionalForce: ())
+    let header = RawKeyPathComponent.Header(optionalForce: ())
     unsafe pushDest(header)
   }
 
@@ -4043,7 +4420,6 @@ internal struct ValidatingInstantiateKeyPathBuffer: KeyPathPatternVisitor {
                                             offset: offset)
     unsafe checkSizeConsistency()
     unsafe structOffset = unsafe instantiateVisitor.structOffset
-    unsafe isPureStruct.append(contentsOf: instantiateVisitor.isPureStruct)
   }
   mutating func visitComputedComponent(mutating: Bool,
                                    idKind: KeyPathComputedIDKind,
@@ -4075,31 +4451,26 @@ internal struct ValidatingInstantiateKeyPathBuffer: KeyPathPatternVisitor {
     // Note: For this function and the ones below, modification of structOffset
     // is omitted since these types of KeyPaths won't have a pureStruct
     // offset anyway.
-    unsafe isPureStruct.append(contentsOf: instantiateVisitor.isPureStruct)
     unsafe checkSizeConsistency()
   }
   mutating func visitOptionalChainComponent() {
     unsafe sizeVisitor.visitOptionalChainComponent()
     unsafe instantiateVisitor.visitOptionalChainComponent()
-    unsafe isPureStruct.append(contentsOf: instantiateVisitor.isPureStruct)
     unsafe checkSizeConsistency()
   }
   mutating func visitOptionalWrapComponent() {
     unsafe sizeVisitor.visitOptionalWrapComponent()
     unsafe instantiateVisitor.visitOptionalWrapComponent()
-    unsafe isPureStruct.append(contentsOf: instantiateVisitor.isPureStruct)
     unsafe checkSizeConsistency()
   }
   mutating func visitOptionalForceComponent() {
     unsafe sizeVisitor.visitOptionalForceComponent()
     unsafe instantiateVisitor.visitOptionalForceComponent()
-    unsafe isPureStruct.append(contentsOf: instantiateVisitor.isPureStruct)
     unsafe checkSizeConsistency()
   }
   mutating func visitIntermediateComponentType(metadataRef: MetadataReference) {
     unsafe sizeVisitor.visitIntermediateComponentType(metadataRef: metadataRef)
     unsafe instantiateVisitor.visitIntermediateComponentType(metadataRef: metadataRef)
-    unsafe isPureStruct.append(contentsOf: instantiateVisitor.isPureStruct)
     unsafe checkSizeConsistency()
   }
 
@@ -4152,7 +4523,7 @@ internal func _instantiateKeyPathBuffer(
   var walker = unsafe ValidatingInstantiateKeyPathBuffer(sizeVisitor: sizeWalker,
                                           instantiateVisitor: instantiateWalker)
 #else
-  var walker = InstantiateKeyPathBuffer(
+  var walker = unsafe InstantiateKeyPathBuffer(
     destData: destData,
     patternArgs: arguments,
     root: rootType)
@@ -4165,8 +4536,8 @@ internal func _instantiateKeyPathBuffer(
   let endOfReferencePrefixComponent =
     unsafe walker.instantiateVisitor.endOfReferencePrefixComponent
 #else
-  let isTrivial = walker.isTrivial
-  let endOfReferencePrefixComponent = walker.endOfReferencePrefixComponent
+  let isTrivial = unsafe walker.isTrivial
+  let endOfReferencePrefixComponent = unsafe walker.endOfReferencePrefixComponent
 #endif
 
   // Write out the header.
@@ -4183,7 +4554,7 @@ internal func _instantiateKeyPathBuffer(
   if let endOfReferencePrefixComponent = unsafe endOfReferencePrefixComponent {
     var componentHeader = unsafe endOfReferencePrefixComponent
       .load(as: RawKeyPathComponent.Header.self)
-    unsafe componentHeader.endOfReferencePrefix = true
+    componentHeader.endOfReferencePrefix = true
     unsafe endOfReferencePrefixComponent.storeBytes(of: componentHeader,
       as: RawKeyPathComponent.Header.self)
   }
@@ -4224,7 +4595,7 @@ public func _createOffsetBasedKeyPath(
   let kpBufferSize = MemoryLayout<Int>.size + MemoryLayout<Int32>.size
   let kp = unsafe kpTy._create(capacityInBytes: kpBufferSize) {
     var builder = unsafe KeyPathBuffer.Builder($0)
-    let header = unsafe KeyPathBuffer.Header(
+    let header = KeyPathBuffer.Header(
       size: kpBufferSize - MemoryLayout<Int>.size,
       trivial: true,
       hasReferencePrefix: false,
@@ -4233,7 +4604,7 @@ public func _createOffsetBasedKeyPath(
 
     unsafe builder.pushHeader(header)
 
-    let componentHeader = unsafe RawKeyPathComponent.Header(
+    let componentHeader = RawKeyPathComponent.Header(
       stored: _MetadataKind(root) == .struct ? .struct : .class,
       mutable: false,
       inlineOffset: UInt32(offset)
@@ -4244,7 +4615,13 @@ public func _createOffsetBasedKeyPath(
       body: UnsafeRawBufferPointer(start: nil, count: 0)
     )
 
-    unsafe component.clone(into: &builder.buffer, endOfReferencePrefix: false)
+    unsafe component.clone(
+      into: &builder.buffer,
+      endOfReferencePrefix: false,
+
+      // The keypath will have the same shape, it's just the types that differ.
+      adjustForAlignment: false
+    )
   }
 
   if _MetadataKind(root) == .struct {
@@ -4301,7 +4678,7 @@ public func _rerootKeyPath<NewRoot>(
     capacityInBytes: capacity
   ) {
     var builder = unsafe KeyPathBuffer.Builder($0)
-    let header = unsafe KeyPathBuffer.Header(
+    let header = KeyPathBuffer.Header(
       size: componentSize,
       trivial: isTrivial,
       hasReferencePrefix: hasReferencePrefix,
@@ -4318,7 +4695,11 @@ public func _rerootKeyPath<NewRoot>(
 
         unsafe rawComponent.clone(
           into: &builder.buffer,
-          endOfReferencePrefix: rawComponent.header.endOfReferencePrefix
+          endOfReferencePrefix: rawComponent.header.endOfReferencePrefix,
+
+          // Simply changing the type of the root type, so the resulting buffer
+          // will have the same layout.
+          adjustForAlignment: false
         )
 
         if componentTy == nil {
@@ -4393,13 +4774,13 @@ extension AnyKeyPath: CustomDebugStringConvertible {
         let (rawComponent, optNextType) = unsafe buffer.next()
         let hasEnded = optNextType == nil
         let nextType = optNextType ?? Self.valueType
-        switch unsafe rawComponent.value {
+        switch rawComponent.value {
         case .optionalForce, .optionalWrap, .optionalChain:
           break
         default:
           description.append(".")
         }
-        switch unsafe rawComponent.value {
+        switch rawComponent.value {
         case .class(let offset),
             .struct(let offset):
           let count = _getRecursiveChildCount(valueType)
@@ -4429,7 +4810,7 @@ extension AnyKeyPath: CustomDebugStringConvertible {
             .mutatingGetSet(_, let accessors, _):
           func project<Base>(base: Base.Type) -> String {
             func project2<Leaf>(leaf: Leaf.Type) -> String {
-              unsafe dynamicLibraryAddress(
+              dynamicLibraryAddress(
                 of: accessors,
                 base,
                 leaf
diff --git a/stdlib/public/core/KeyValuePairs.swift b/stdlib/public/core/KeyValuePairs.swift
index dd0d76a017f57..24b53d0336b79 100644
--- a/stdlib/public/core/KeyValuePairs.swift
+++ b/stdlib/public/core/KeyValuePairs.swift
@@ -125,12 +125,13 @@ extension KeyValuePairs: RandomAccessCollection {
   }
 }
 
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension KeyValuePairs {
-  
-  @available(SwiftStdlib 6.2, *)
+  @available(SwiftCompatibilitySpan 5.0, *)
+  @_alwaysEmitIntoClient
   public var span: Span<Element> {
     @lifetime(borrow self)
-    @_alwaysEmitIntoClient
     get {
       let rp = unsafe UnsafeRawPointer(_elements._buffer.firstElementAddress)
       let span = unsafe Span(
diff --git a/stdlib/public/core/LifetimeManager.swift b/stdlib/public/core/LifetimeManager.swift
index 34c8aefbb7712..8d51e453bcedc 100644
--- a/stdlib/public/core/LifetimeManager.swift
+++ b/stdlib/public/core/LifetimeManager.swift
@@ -184,6 +184,7 @@ public func withUnsafePointer<T: ~Copyable, E: Error, Result: ~Copyable>(
   return try unsafe body(UnsafePointer<T>(Builtin.addressOfBorrow(value)))
 }
 
+#if !$Embedded
 /// ABI: Historical withUnsafePointer(to:_:) rethrows, expressed as "throws",
 /// which is ABI-compatible with "rethrows".
 @_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@@ -196,6 +197,7 @@ internal func __abi_withUnsafePointer<T, Result>(
 {
   return try unsafe body(UnsafePointer<T>(Builtin.addressOfBorrow(value)))
 }
+#endif
 
 /// Invokes the given closure with a pointer to the given argument.
 ///
@@ -229,6 +231,7 @@ public func withUnsafePointer<T: ~Copyable, E: Error, Result: ~Copyable>(
   try unsafe body(UnsafePointer<T>(Builtin.addressof(&value)))
 }
 
+#if !$Embedded
 /// ABI: Historical withUnsafePointer(to:_:) rethrows,
 /// expressed as "throws", which is ABI-compatible with "rethrows".
 @_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@@ -240,6 +243,7 @@ internal func __abi_se0413_withUnsafePointer<T, Result>(
 ) throws -> Result {
   return try unsafe body(UnsafePointer<T>(Builtin.addressof(&value)))
 }
+#endif
 
 /// Invokes the given closure with a pointer to the given argument.
 ///
@@ -290,13 +294,11 @@ public func _copy<T>(_ value: T) -> T {
 @_alwaysEmitIntoClient
 @_transparent
 @lifetime(borrow source)
-internal func _overrideLifetime<
+public func _overrideLifetime<
   T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
 >(
   _ dependent: consuming T, borrowing source: borrowing U
 ) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
   dependent
 }
 
@@ -308,13 +310,11 @@ internal func _overrideLifetime<
 @_alwaysEmitIntoClient
 @_transparent
 @lifetime(copy source)
-internal func _overrideLifetime<
+public func _overrideLifetime<
   T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
 >(
   _ dependent: consuming T, copying source: borrowing U
 ) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
   dependent
 }
 
@@ -325,14 +325,12 @@ internal func _overrideLifetime<
 @_unsafeNonescapableResult
 @_alwaysEmitIntoClient
 @_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<
+@lifetime(&source)
+public func _overrideLifetime<
   T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
 >(
   _ dependent: consuming T,
   mutating source: inout U
 ) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
   dependent
 }
diff --git a/stdlib/public/core/Mirror.swift b/stdlib/public/core/Mirror.swift
index 5d94615ac7463..960652c6546b1 100644
--- a/stdlib/public/core/Mirror.swift
+++ b/stdlib/public/core/Mirror.swift
@@ -313,6 +313,7 @@ extension Mirror {
   public enum DisplayStyle: Sendable {
     case `struct`, `class`, `enum`, tuple, optional, collection
     case dictionary, `set`
+    @available(SwiftStdlib 6.2, *) case foreignReference
   }
 
   internal static func _noSuperclassMirror() -> Mirror? { return nil }
@@ -481,6 +482,7 @@ public struct Mirror {
   public enum DisplayStyle: Sendable {
     case `struct`, `class`, `enum`, tuple, optional, collection
     case dictionary, `set`
+    @available(SwiftStdlib 6.2, *) case foreignReference
   }
   public init<Subject, C: Collection>(
     _ subject: Subject,
diff --git a/stdlib/public/core/MutableCollection.swift b/stdlib/public/core/MutableCollection.swift
index e183e3946b6f1..ac81e4d15e52d 100644
--- a/stdlib/public/core/MutableCollection.swift
+++ b/stdlib/public/core/MutableCollection.swift
@@ -379,8 +379,8 @@ extension MutableCollection {
   ///     var letters = Array("ABCdeFGhijkLMNOp")
   ///     let uppercaseRanges = letters.indices(where: { $0.isUppercase })
   ///     let rangeOfUppercase = letters.moveSubranges(uppercaseRanges, to: 10)
-  ///     // String(letters) == "dehiABCFGLMNOjkp"
-  ///     // rangeOfUppercase == 4..<13
+  ///     // String(letters) == "dehijABCFGLMNOkp"
+  ///     // rangeOfUppercase == 5..<14
   ///
   /// - Parameters:
   ///   - subranges: The subranges of the elements to move.
diff --git a/stdlib/public/core/NFC.swift b/stdlib/public/core/NFC.swift
index 9e5cf8f8e17e0..a78825fbf54c2 100644
--- a/stdlib/public/core/NFC.swift
+++ b/stdlib/public/core/NFC.swift
@@ -137,7 +137,7 @@ extension Unicode {
     /// consuming elements from the given source as necessary.
     ///
     /// If the normalizer returns `nil`, the source was exhausted.
-    /// One a source is exhausted, you may:
+    /// Once a source is exhausted, you may:
     ///
     /// - Call `resume` again some time later with a different source
     ///   to continue processing the same logical text stream, or
diff --git a/stdlib/public/core/NativeDictionary.swift b/stdlib/public/core/NativeDictionary.swift
index d7eba4c7e583e..039ce5eef3a81 100644
--- a/stdlib/public/core/NativeDictionary.swift
+++ b/stdlib/public/core/NativeDictionary.swift
@@ -120,6 +120,7 @@ extension _NativeDictionary { // Primitive fields
 extension _NativeDictionary { // Low-level unchecked operations
   @inlinable
   @inline(__always)
+  @unsafe
   internal func uncheckedKey(at bucket: Bucket) -> Key {
     defer { _fixLifetime(self) }
     unsafe _internalInvariant(hashTable.isOccupied(bucket))
@@ -128,6 +129,7 @@ extension _NativeDictionary { // Low-level unchecked operations
 
   @inlinable
   @inline(__always)
+  @unsafe
   internal func uncheckedValue(at bucket: Bucket) -> Value {
     defer { _fixLifetime(self) }
     unsafe _internalInvariant(hashTable.isOccupied(bucket))
@@ -136,6 +138,7 @@ extension _NativeDictionary { // Low-level unchecked operations
 
   @inlinable // FIXME(inline-always) was usableFromInline
   @inline(__always)
+  @unsafe
   internal func uncheckedInitialize(
     at bucket: Bucket,
     toKey key: __owned Key,
@@ -148,6 +151,7 @@ extension _NativeDictionary { // Low-level unchecked operations
 
   @inlinable // FIXME(inline-always) was usableFromInline
   @inline(__always)
+  @unsafe
   internal func uncheckedDestroy(at bucket: Bucket) {
     defer { _fixLifetime(self) }
     unsafe _internalInvariant(hashTable.isValid(bucket))
@@ -300,7 +304,7 @@ extension _NativeDictionary {
         let key = _forceBridgeFromObjectiveC(cocoa.key, Key.self)
         let (bucket, found) = find(key)
         if found {
-          return unsafe bucket
+          return bucket
         }
       }
       _preconditionFailure(
@@ -331,7 +335,7 @@ extension _NativeDictionary: _DictionaryBuffer {
   internal func index(after index: Index) -> Index {
 #if _runtime(_ObjC)
     guard _fastPath(index._isNative) else {
-      let _ = unsafe validatedBucket(for: index)
+      let _ = validatedBucket(for: index)
       let i = index._asCocoa
       return Index(_cocoa: i.dictionary.index(after: i))
     }
@@ -384,7 +388,7 @@ extension _NativeDictionary: _DictionaryBuffer {
   @inlinable
   @inline(__always)
   func lookup(_ index: Index) -> (key: Key, value: Value) {
-    let bucket = unsafe validatedBucket(for: index)
+    let bucket = validatedBucket(for: index)
     let key = unsafe self.uncheckedKey(at: bucket)
     let value = unsafe self.uncheckedValue(at: bucket)
     return (key, value)
@@ -393,14 +397,14 @@ extension _NativeDictionary: _DictionaryBuffer {
   @inlinable
   @inline(__always)
   func key(at index: Index) -> Key {
-    let bucket = unsafe validatedBucket(for: index)
+    let bucket = validatedBucket(for: index)
     return unsafe self.uncheckedKey(at: bucket)
   }
 
   @inlinable
   @inline(__always)
   func value(at index: Index) -> Value {
-    let bucket = unsafe validatedBucket(for: index)
+    let bucket = validatedBucket(for: index)
     return unsafe self.uncheckedValue(at: bucket)
   }
 }
@@ -429,14 +433,14 @@ extension _NativeDictionary {
           } else {
             // **Insertion.** Insert the new entry at the correct place.  Note
             // that `mutatingFind` already ensured that we have enough capacity.
-            unsafe _insert(at: bucket, key: key, value: value)
+            _insert(at: bucket, key: key, value: value)
           }
         } else {
           if found {
             // **Removal.** We've already deinitialized the value; deinitialize
             // the key too and register the removal.
             unsafe (_keys + bucket.offset).deinitialize(count: 1)
-            unsafe _delete(at: bucket)
+            _delete(at: bucket)
           } else {
             // Noop
           }
@@ -477,7 +481,7 @@ extension _NativeDictionary { // Insertions
       // elements -- these imply that the Element type violates Hashable
       // requirements. This is generally more costly than a direct insertion,
       // because we'll need to compare elements in case of hash collisions.
-      let (bucket, found) = unsafe find(key, hashValue: hashValue)
+      let (bucket, found) = find(key, hashValue: hashValue)
       guard !found else {
         #if !$Embedded
         KEY_TYPE_OF_DICTIONARY_VIOLATES_HASHABLE_REQUIREMENTS(Key.self)
@@ -512,7 +516,7 @@ extension _NativeDictionary { // Insertions
       unsafe (_values + bucket.offset).pointee = value
     } else {
       _precondition(count < capacity)
-      unsafe _insert(at: bucket, key: key, value: value)
+      _insert(at: bucket, key: key, value: value)
     }
   }
 
@@ -546,7 +550,7 @@ extension _NativeDictionary { // Insertions
     let rehashed = ensureUnique(
       isUnique: isUnique,
       capacity: count + (found ? 0 : 1))
-    guard rehashed else { return unsafe (bucket, found) }
+    guard rehashed else { return (bucket, found) }
     let (b, f) = find(key)
     if f != found {
       #if !$Embedded
@@ -555,7 +559,7 @@ extension _NativeDictionary { // Insertions
       fatalError("duplicate keys in a Dictionary")
       #endif
     }
-    return unsafe (b, found)
+    return (b, found)
   }
 
   @inlinable
@@ -581,7 +585,7 @@ extension _NativeDictionary { // Insertions
       unsafe (_values + bucket.offset).initialize(to: value)
       return oldValue
     }
-    unsafe _insert(at: bucket, key: key, value: value)
+    _insert(at: bucket, key: key, value: value)
     return nil
   }
 
@@ -595,7 +599,7 @@ extension _NativeDictionary { // Insertions
     if found {
       unsafe (_values + bucket.offset).pointee = value
     } else {
-      unsafe _insert(at: bucket, key: key, value: value)
+      _insert(at: bucket, key: key, value: value)
     }
   }
 }
@@ -716,6 +720,7 @@ extension _NativeDictionary { // Deletion
 
   @inlinable
   @_semantics("optimize.sil.specialize.generic.size.never")
+  @unsafe
   internal mutating func uncheckedRemove(
     at bucket: Bucket,
     isUnique: Bool
@@ -725,7 +730,7 @@ extension _NativeDictionary { // Deletion
     _internalInvariant(!rehashed)
     let oldKey = unsafe (_keys + bucket.offset).move()
     let oldValue = unsafe (_values + bucket.offset).move()
-    unsafe _delete(at: bucket)
+    _delete(at: bucket)
     return (oldKey, oldValue)
   }
 
@@ -763,7 +768,7 @@ extension _NativeDictionary { // High-level operations
     for unsafe bucket in unsafe hashTable {
       let key = unsafe self.uncheckedKey(at: bucket)
       let value = unsafe self.uncheckedValue(at: bucket)
-      try unsafe result._insert(at: bucket, key: key, value: transform(value))
+      try result._insert(at: bucket, key: key, value: transform(value))
     }
     return result
   }
@@ -790,7 +795,7 @@ extension _NativeDictionary { // High-level operations
           #endif
         }
       } else {
-        unsafe _insert(at: bucket, key: key, value: value)
+        _insert(at: bucket, key: key, value: value)
       }
     }
   }
@@ -818,7 +823,7 @@ extension _NativeDictionary { // High-level operations
           #endif
         }
       } else {
-        unsafe _insert(at: bucket, key: key, value: value)
+        _insert(at: bucket, key: key, value: value)
       }
     }
   }
@@ -837,7 +842,7 @@ extension _NativeDictionary { // High-level operations
       if found {
         unsafe _values[bucket.offset].append(value)
       } else {
-        unsafe _insert(at: bucket, key: key, value: [value])
+        _insert(at: bucket, key: key, value: [value])
       }
     }
   }
diff --git a/stdlib/public/core/NativeSet.swift b/stdlib/public/core/NativeSet.swift
index f16fac868cfd9..b623f4a24859d 100644
--- a/stdlib/public/core/NativeSet.swift
+++ b/stdlib/public/core/NativeSet.swift
@@ -117,6 +117,7 @@ extension _NativeSet { // Primitive fields
 extension _NativeSet { // Low-level unchecked operations
   @inlinable
   @inline(__always)
+  @unsafe
   internal func uncheckedElement(at bucket: Bucket) -> Element {
     defer { _fixLifetime(self) }
     unsafe _internalInvariant(hashTable.isOccupied(bucket))
@@ -125,6 +126,7 @@ extension _NativeSet { // Low-level unchecked operations
 
   @inlinable
   @inline(__always)
+  @unsafe
   internal func uncheckedInitialize(
     at bucket: Bucket,
     to element: __owned Element
@@ -135,6 +137,7 @@ extension _NativeSet { // Low-level unchecked operations
 
   @_alwaysEmitIntoClient @inlinable // Introduced in 5.1
   @inline(__always)
+  @unsafe
   internal func uncheckedAssign(
     at bucket: Bucket,
     to element: __owned Element
@@ -155,7 +158,7 @@ extension _NativeSet { // Low-level lookup operations
   @inlinable
   @inline(__always)
   internal func find(_ element: Element) -> (bucket: Bucket, found: Bool) {
-    return unsafe find(element, hashValue: self.hashValue(for: element))
+    return find(element, hashValue: self.hashValue(for: element))
   }
 
   /// Search for a given element, assuming it has the specified hash value.
@@ -172,11 +175,11 @@ extension _NativeSet { // Low-level lookup operations
     var bucket = unsafe hashTable.idealBucket(forHashValue: hashValue)
     while unsafe hashTable._isOccupied(bucket) {
       if unsafe uncheckedElement(at: bucket) == element {
-        return unsafe (bucket, true)
+        return (bucket, true)
       }
-      unsafe bucket = unsafe hashTable.bucket(wrappedAfter: bucket)
+      bucket = unsafe hashTable.bucket(wrappedAfter: bucket)
     }
-    return unsafe (bucket, false)
+    return (bucket, false)
   }
 }
 
@@ -191,7 +194,7 @@ extension _NativeSet { // ensureUnique
     if count > 0 {
       for unsafe bucket in unsafe hashTable {
         let element = unsafe (self._elements + bucket.offset).move()
-        result._unsafeInsertNew(element)
+        unsafe result._unsafeInsertNew(element)
       }
       // Clear out old storage, ensuring that its deinit won't overrelease the
       // elements we've just moved out.
@@ -283,7 +286,7 @@ extension _NativeSet {
         let element = _forceBridgeFromObjectiveC(cocoa.element, Element.self)
         let (bucket, found) = find(element)
         if found {
-          return unsafe bucket
+          return bucket
         }
       }
       _preconditionFailure(
@@ -348,7 +351,7 @@ extension _NativeSet: _SetBuffer {
   @inlinable
   @inline(__always)
   internal func element(at index: Index) -> Element {
-    let bucket = unsafe validatedBucket(for: index)
+    let bucket = validatedBucket(for: index)
     return unsafe uncheckedElement(at: bucket)
   }
 }
@@ -375,6 +378,7 @@ extension _NativeSet { // Insertions
   /// Storage must be uniquely referenced with adequate capacity.
   /// The `element` must not be already present in the Set.
   @inlinable
+  @unsafe
   internal func _unsafeInsertNew(_ element: __owned Element) {
     _internalInvariant(count + 1 <= capacity)
     let hashValue = self.hashValue(for: element)
@@ -383,7 +387,7 @@ extension _NativeSet { // Insertions
       // elements -- these imply that the Element type violates Hashable
       // requirements. This is generally more costly than a direct insertion,
       // because we'll need to compare elements in case of hash collisions.
-      let (bucket, found) = unsafe find(element, hashValue: hashValue)
+      let (bucket, found) = find(element, hashValue: hashValue)
       guard !found else {
         #if !$Embedded
         ELEMENT_TYPE_OF_SET_VIOLATES_HASHABLE_REQUIREMENTS(Element.self)
@@ -406,10 +410,11 @@ extension _NativeSet { // Insertions
   @inlinable
   internal mutating func insertNew(_ element: __owned Element, isUnique: Bool) {
     _ = ensureUnique(isUnique: isUnique, capacity: count + 1)
-    _unsafeInsertNew(element)
+    unsafe _unsafeInsertNew(element)
   }
 
   @inlinable
+  @unsafe
   internal func _unsafeInsertNew(_ element: __owned Element, at bucket: Bucket) {
     unsafe hashTable.insert(bucket)
     unsafe uncheckedInitialize(at: bucket, to: element)
@@ -423,7 +428,7 @@ extension _NativeSet { // Insertions
     isUnique: Bool
   ) {
     unsafe _internalInvariant(!hashTable.isOccupied(bucket))
-    var bucket = unsafe bucket
+    var bucket = bucket
     let rehashed = ensureUnique(isUnique: isUnique, capacity: count + 1)
     if rehashed {
       let (b, f) = find(element)
@@ -434,7 +439,7 @@ extension _NativeSet { // Insertions
         fatalError("duplicate elements in a Set")
         #endif
       }
-      unsafe bucket = unsafe b
+      bucket = b
     }
     unsafe _unsafeInsertNew(element, at: bucket)
   }
@@ -457,7 +462,7 @@ extension _NativeSet { // Insertions
         fatalError("duplicate elements in a Set")
         #endif
       }
-      unsafe bucket = unsafe b
+      bucket = b
     }
     if found {
       let old = unsafe (_elements + bucket.offset).move()
@@ -540,6 +545,7 @@ extension _NativeSet { // Deletion
 
   @inlinable
   @inline(__always)
+  @unsafe
   internal mutating func uncheckedRemove(
     at bucket: Bucket,
     isUnique: Bool) -> Element {
@@ -547,7 +553,7 @@ extension _NativeSet { // Deletion
     let rehashed = ensureUnique(isUnique: isUnique, capacity: capacity)
     _internalInvariant(!rehashed)
     let old = unsafe (_elements + bucket.offset).move()
-    unsafe _delete(at: bucket)
+    _delete(at: bucket)
     return old
   }
 
@@ -710,11 +716,11 @@ extension _NativeSet {
     while let next = it.next() {
       let (b, found) = find(next)
       if found {
-        unsafe bucket = unsafe b
+        bucket = b
         break
       }
     }
-    guard let bucket = unsafe bucket else { return self }
+    guard let bucket = bucket else { return self }
 
     // Rather than directly creating a new set, calculate the difference in a
     // bitset first. This ensures we hash each element (in both sets) only once,
diff --git a/stdlib/public/core/ObjectIdentifier.swift b/stdlib/public/core/ObjectIdentifier.swift
index cf949f05dc3a0..e4b4dc5349a53 100644
--- a/stdlib/public/core/ObjectIdentifier.swift
+++ b/stdlib/public/core/ObjectIdentifier.swift
@@ -12,13 +12,14 @@
 
 #if !$Embedded
 
-/// A unique identifier for a class instance or metatype.
+/// A unique identifier for a class instance, actor instance, or metatype.
 ///
-/// This unique identifier is only valid for comparisons during the lifetime
+/// This unique identifier is valid for comparisons only during the lifetime
 /// of the instance.
 ///
-/// In Swift, only class instances and metatypes have unique identities. There
-/// is no notion of identity for structs, enums, functions, or tuples.
+/// In Swift, only instances of classes, instances of actors, and metatypes
+/// have unique identities. There's no notion of identity for structures,
+/// enumerations, functions, or tuples.
 @frozen // trivial-implementation
 public struct ObjectIdentifier: Sendable {
   @usableFromInline // trivial-implementation
diff --git a/stdlib/public/core/OptionSet.swift b/stdlib/public/core/OptionSet.swift
index 427a33d960edc..33699da10778f 100644
--- a/stdlib/public/core/OptionSet.swift
+++ b/stdlib/public/core/OptionSet.swift
@@ -374,3 +374,15 @@ extension OptionSet where RawValue: FixedWidthInteger {
     self = Self(rawValue: self.rawValue ^ other.rawValue)
   }
 }
+
+extension OptionSet where RawValue: FixedWidthInteger, Element == Self {
+  @_alwaysEmitIntoClient
+  @discardableResult
+  public mutating func insert(
+    _ newMember: Element
+  ) -> (inserted: Bool, memberAfterInsert: Element) {
+    let inserted = !self.contains(newMember)
+    self = Self(rawValue: self.rawValue | newMember.rawValue)
+    return (inserted, newMember)
+  }
+}
diff --git a/stdlib/public/core/OutputStream.swift b/stdlib/public/core/OutputStream.swift
index 39c8d01308f1d..37ee91263b2fa 100644
--- a/stdlib/public/core/OutputStream.swift
+++ b/stdlib/public/core/OutputStream.swift
@@ -381,6 +381,10 @@ internal func _adHocPrint_unlocked<T, TargetStream: TextOutputStream>(
             target.write(")")
           }
         }
+      case .foreignReference:
+        printTypeName(mirror.subjectType)
+        // FRT has no children
+        target.write("()")
       default:
         target.write(_typeName(mirror.subjectType))
     }
@@ -526,7 +530,7 @@ internal func _dumpPrint_unlocked<T, TargetStream: TextOutputStream>(
 
   if let displayStyle = mirror.displayStyle {
     switch displayStyle {
-    case .`class`, .`struct`:
+    case .`class`, .`struct`, .foreignReference:
       // Classes and structs without custom representations are displayed as
       // their fully qualified type name
       target.write(_typeName(mirror.subjectType, qualified: true))
diff --git a/stdlib/public/core/Pointer.swift b/stdlib/public/core/Pointer.swift
index 3fc7e0ee3199b..d74ef63ca80fe 100644
--- a/stdlib/public/core/Pointer.swift
+++ b/stdlib/public/core/Pointer.swift
@@ -304,12 +304,12 @@ extension _Pointer /*: Strideable*/ {
 
 extension _Pointer /*: Hashable */ {
   @inlinable
-  public func hash(into hasher: inout Hasher) {
+  @safe public func hash(into hasher: inout Hasher) {
     hasher.combine(UInt(bitPattern: self))
   }
 
   @inlinable
-  public func _rawHashValue(seed: Int) -> Int {
+  @safe public func _rawHashValue(seed: Int) -> Int {
     return Hasher._hash(seed: seed, UInt(bitPattern: self))
   }
 }
@@ -317,14 +317,14 @@ extension _Pointer /*: Hashable */ {
 @_unavailableInEmbedded
 extension _Pointer /*: CustomDebugStringConvertible */ {
   /// A textual representation of the pointer, suitable for debugging.
-  public var debugDescription: String {
+  @safe public var debugDescription: String {
     return _rawPointerToString(_rawValue)
   }
 }
 
 #if SWIFT_ENABLE_REFLECTION
 extension _Pointer /*: CustomReflectable */ {
-  public var customMirror: Mirror {
+  @safe public var customMirror: Mirror {
     let ptrValue = UInt64(
       bitPattern: Int64(Int(Builtin.ptrtoint_Word(_rawValue))))
     return Mirror(self, children: ["pointerValue": ptrValue])
diff --git a/stdlib/public/core/PreviousModuleInstallName.json b/stdlib/public/core/PreviousModuleInstallName.json
index 6734469d84550..dce898975ab37 100644
--- a/stdlib/public/core/PreviousModuleInstallName.json
+++ b/stdlib/public/core/PreviousModuleInstallName.json
@@ -1,6 +1,6 @@
 [
   {
     "module": "CompatibilitySpan",
-    "install_name": "/usr/lib/swift/libswiftCompatibilitySpan.dylib"
+    "install_name": "@rpath/libswiftCompatibilitySpan.dylib"
   }
 ]
diff --git a/stdlib/public/core/Range.swift b/stdlib/public/core/Range.swift
index 2b3d062b9ce48..5f650d784ed56 100644
--- a/stdlib/public/core/Range.swift
+++ b/stdlib/public/core/Range.swift
@@ -94,9 +94,10 @@ extension RangeExpression {
   ///   - pattern: A range.
   ///   - bound: A value to match against `pattern`.
   @inlinable
+  @inline(__always)
   public static func ~= (pattern: Self, value: Bound) -> Bool {
     return pattern.contains(value)
-  }  
+  }
 }
 
 /// A half-open interval from a lower bound up to, but not including, an upper
@@ -194,7 +195,7 @@ public struct Range<Bound: Comparable> {
   /// - Parameter element: The element to check for containment.
   /// - Returns: `true` if `element` is contained in the range; otherwise,
   ///   `false`.
-  @inlinable
+  @_transparent
   public func contains(_ element: Bound) -> Bool {
     return lowerBound <= element && element < upperBound
   }
@@ -682,7 +683,7 @@ extension PartialRangeFrom: RangeExpression {
   ) -> Range<Bound> where C.Index == Bound {
     return self.lowerBound..<collection.endIndex
   }
-  @inlinable // trivial-implementation
+  @_transparent
   public func contains(_ element: Bound) -> Bool {
     return lowerBound <= element
   }
@@ -1074,11 +1075,12 @@ extension Range {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
+  @_transparent
   public func contains(_ other: Range<Bound>) -> Bool {
     other.isEmpty ||
       (lowerBound <= other.lowerBound && upperBound >= other.upperBound)
   }
-  
+
   /// Returns a Boolean value indicating whether the given closed range is
   /// contained within this range.
   ///
@@ -1101,6 +1103,7 @@ extension Range {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
+  @_transparent
   public func contains(_ other: ClosedRange<Bound>) -> Bool {
     lowerBound <= other.lowerBound && upperBound > other.upperBound
   }
diff --git a/stdlib/public/core/ReflectionMirror.swift b/stdlib/public/core/ReflectionMirror.swift
index b4639050f61bf..3a32b38a6a6c8 100644
--- a/stdlib/public/core/ReflectionMirror.swift
+++ b/stdlib/public/core/ReflectionMirror.swift
@@ -172,6 +172,12 @@ extension Mirror {
     case "e": self.displayStyle = .enum
     case "s": self.displayStyle = .struct
     case "t": self.displayStyle = .tuple
+    case "f":  
+      if #available(SwiftStdlib 6.2, *) {
+        self.displayStyle = .foreignReference
+      } else {
+        self.displayStyle = nil
+      }
     case "\0": self.displayStyle = nil
     default: preconditionFailure("Unknown raw display style '\(rawDisplayStyle)'")
     }
@@ -372,7 +378,11 @@ public func _forEachFieldWithKeyPath<Root>(
            body: UnsafeRawBufferPointer(start: nil, count: 0))
       unsafe component.clone(
         into: &destBuilder.buffer,
-        endOfReferencePrefix: false)
+        endOfReferencePrefix: false,
+
+        // We are just storing offset components and not computed ones.
+        adjustForAlignment: false
+      )
     }
 
     if let name = unsafe field.name {
diff --git a/stdlib/public/core/SIMDConcreteOperations.swift.gyb b/stdlib/public/core/SIMDConcreteOperations.swift.gyb
deleted file mode 100644
index bcaefd7c550c8..0000000000000
--- a/stdlib/public/core/SIMDConcreteOperations.swift.gyb
+++ /dev/null
@@ -1,371 +0,0 @@
-//===--- SIMDConcreteOperations.swift -------------------------*- swift -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-%{
-from SwiftIntTypes import all_integer_types
-word_bits = int(CMAKE_SIZEOF_VOID_P) * 8
-storagescalarCounts = [2,4,8,16,32,64]
-vectorscalarCounts = storagescalarCounts + [3]
-}%
-
-%for int in all_integer_types(word_bits):
-% Scalar = int.stdlib_name
-% for n in vectorscalarCounts:
-%  Vector = "SIMD" + str(n) + "<" + Scalar + ">"
-%  storageN = 4 if n == 3 else n
-%  s = "s" if int.is_signed else "u"
-%  Builtin = "Vec" + str(storageN) + "xInt" + str(int.bits)
-%  MaskExt = "Builtin.sext_Vec" + str(storageN) + "xInt1_" + Builtin
-%  if int.is_signed:
-extension SIMDMask where Storage == ${Vector} {
-  @_alwaysEmitIntoClient
-  internal init(_ _builtin: Builtin.${Builtin}) {
-    _storage = ${Vector}(_builtin)
-  }
-  
-  @_alwaysEmitIntoClient
-  internal static var allTrue: Self {
-    let zero = ${Vector}()
-    return zero .== zero
-  }
-  
-  /// A vector mask that is the pointwise logical negation of the input.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// var result = SIMDMask<${Vector}>()
-  /// for i in result.indices {
-  ///   result[i] = !a[i]
-  /// }
-  /// ```
-  @_alwaysEmitIntoClient
-  public static prefix func .!(a: Self) -> Self {
-    a .^ .allTrue
-  }
-    
-  /// A vector mask that is the pointwise logical conjunction of the inputs.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// var result = SIMDMask<${Vector}>()
-  /// for i in result.indices {
-  ///   result[i] = a[i] && b[i]
-  /// }
-  /// ```
-  ///
-  /// Note that unlike the scalar `&&` operator, the SIMD `.&` operator
-  /// always fully evaluates both arguments.
-  @_alwaysEmitIntoClient
-  public static func .&(a: Self, b: Self) -> Self {
-    Self(${Vector}(Builtin.and_${Builtin}(
-      a._storage._storage._value,
-      b._storage._storage._value
-    )))
-  }
-    
-  /// Replaces `a` with the pointwise logical conjunction of `a` and `b`.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// for i in a.indices {
-  ///   a[i] = a[i] && b[i]
-  /// }
-  /// ```
-  @_alwaysEmitIntoClient
-  public static func .&=(a: inout Self, b: Self) {
-    a = a .& b
-  }
-      
-  /// A vector mask that is the pointwise exclusive or of the inputs.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// var result = SIMDMask<${Vector}>()
-  /// for i in result.indices {
-  ///   result[i] = a[i] != b[i]
-  /// }
-  /// ```
-  @_alwaysEmitIntoClient
-  public static func .^(a: Self, b: Self) -> Self {
-    Self(${Vector}(Builtin.xor_${Builtin}(
-      a._storage._storage._value,
-      b._storage._storage._value
-    )))
-  }
-    
-  /// Replaces `a` with the pointwise exclusive or of `a` and `b`.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// for i in a.indices {
-  ///   a[i] = a[i] != b[i]
-  /// }
-  /// ```
-  @_alwaysEmitIntoClient
-  public static func .^=(a: inout Self, b: Self) {
-    a = a .^ b
-  }
-      
-  /// A vector mask that is the pointwise logical disjunction of the inputs.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// var result = SIMDMask<${Vector}>()
-  /// for i in result.indices {
-  ///   result[i] = a[i] || b[i]
-  /// }
-  /// ```
-  ///
-  /// Note that unlike the scalar `||` operator, the SIMD `.|` operator
-  /// always fully evaluates both arguments.
-  @_alwaysEmitIntoClient
-  public static func .|(a: Self, b: Self) -> Self {
-    Self(${Vector}(Builtin.or_${Builtin}(
-      a._storage._storage._value,
-      b._storage._storage._value
-    )))
-  }
-    
-  /// Replaces `a` with the pointwise logical disjunction of `a` and `b`.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// for i in a.indices {
-  ///   a[i] = a[i] || b[i]
-  /// }
-  /// ```
-  @_alwaysEmitIntoClient
-  public static func .|=(a: inout Self, b: Self) {
-    a = a .| b
-  }
-    
-  /// A vector mask with the result of a pointwise equality comparison.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// var result = SIMDMask<${Vector}>()
-  /// for i in result.indices {
-  ///   result[i] = a[i] == b[i]
-  /// }
-  /// ```
-  @_alwaysEmitIntoClient
-  public static func .==(a: Self, b: Self) -> Self {
-    .!(a .^ b)
-  }
-  
-  /// A vector mask with the result of a pointwise inequality comparison.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// var result = SIMDMask<${Vector}>()
-  /// for i in result.indices {
-  ///   result[i] = a[i] != b[i]
-  /// }
-  /// ```
-  @_alwaysEmitIntoClient
-  public static func .!=(a: Self, b: Self) -> Self {
-    a .^ b
-  }
-    
-  /// Replaces elements of this vector with elements of `other` in the lanes
-  /// where `mask` is `true`.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// for i in indices {
-  ///   if mask[i] { self[i] = other[i] }
-  /// }
-  /// ```
-  @_alwaysEmitIntoClient
-  public mutating func replace(with other: Self, where mask: Self) {
-    self = replacing(with: other, where: mask)
-  }
-    
-  /// Returns a copy of this vector, with elements replaced by elements of
-  /// `other` in the lanes where `mask` is `true`.
-  ///
-  /// Equivalent to:
-  /// ```
-  /// var result = Self()
-  /// for i in indices {
-  ///   result[i] = mask[i] ? other[i] : self[i]
-  /// }
-  /// ```
-  @_alwaysEmitIntoClient
-  public func replacing(with other: Self, where mask: Self) -> Self {
-    (self .& .!mask) .| (other .& mask)
-  }
-}
-
-%  end
-extension SIMD${n} where Scalar == ${Scalar} {
-  @_alwaysEmitIntoClient
-  internal init(_ _builtin: Builtin.${Builtin}) {
-    _storage = ${Scalar}.SIMD${storageN}Storage(_builtin)
-  }
-    
-  /// A vector mask with the result of a pointwise equality comparison.
-  @_alwaysEmitIntoClient
-  public static func .==(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.cmp_eq_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise inequality comparison.
-  @_alwaysEmitIntoClient
-  public static func .!=(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.cmp_ne_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise less-than comparison.
-  @_alwaysEmitIntoClient
-  public static func .<(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.cmp_${s}lt_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise less-than-or-equal-to comparison.
-  @_alwaysEmitIntoClient
-  public static func .<=(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.cmp_${s}le_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise greater-than comparison.
-  @_alwaysEmitIntoClient
-  public static func .>(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.cmp_${s}gt_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise greater-than-or-equal-to comparison.
-  @_alwaysEmitIntoClient
-  public static func .>=(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.cmp_${s}ge_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-    
-  /// The wrapping sum of two vectors.
-  @_alwaysEmitIntoClient
-  public static func &+(a: Self, b: Self) -> Self {
-    Self(Builtin.add_${Builtin}(a._storage._value, b._storage._value))
-  }
-    
-  /// The wrapping difference of two vectors.
-  @_alwaysEmitIntoClient
-  public static func &-(a: Self, b: Self) -> Self {
-    Self(Builtin.sub_${Builtin}(a._storage._value, b._storage._value))
-  }
-    
-  /// The pointwise wrapping product of two vectors.
-  @_alwaysEmitIntoClient
-  public static func &*(a: Self, b: Self) -> Self {
-    Self(Builtin.mul_${Builtin}(a._storage._value, b._storage._value))
-  }
-        
-  /// Updates the left hand side with the wrapping sum of the two
-  /// vectors.
-  @_alwaysEmitIntoClient
-  public static func &+=(a: inout Self, b: Self) { a = a &+ b }
-    
-  /// Updates the left hand side with the wrapping difference of the two
-  /// vectors.
-  @_alwaysEmitIntoClient
-  public static func &-=(a: inout Self, b: Self) { a = a &- b }
-    
-  /// Updates the left hand side with the pointwise wrapping product of two
-  /// vectors.
-  @_alwaysEmitIntoClient
-  public static func &*=(a: inout Self, b: Self) { a = a &* b }
-}
-
-% end
-%end
-
-%for (Scalar, bits) in [('Float16',16), ('Float',32), ('Double',64)]:
-% for n in vectorscalarCounts:
-%  Vector = "SIMD" + str(n) + "<" + Scalar + ">"
-%  storageN = 4 if n == 3 else n
-%  Builtin = "Vec" + str(storageN) + "xFPIEEE" + str(bits)
-%  VecPre = "Vec" + str(storageN) + "x"
-%  MaskExt = "Builtin.sext_" + VecPre + "Int1_" + VecPre + "Int" + str(bits)
-%  if bits == 16:
-#if !((os(macOS) || targetEnvironment(macCatalyst)) && arch(x86_64))
-@available(SwiftStdlib 5.3, *)
-%  end
-extension SIMD${n} where Scalar == ${Scalar} {
-  @_alwaysEmitIntoClient
-  internal init(_ _builtin: Builtin.${Builtin}) {
-    _storage = ${Scalar}.SIMD${storageN}Storage(_builtin)
-  }
-  
-  /// A vector mask with the result of a pointwise equality comparison.
-  @_alwaysEmitIntoClient
-  public static func .==(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.fcmp_oeq_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise inequality comparison.
-  @_alwaysEmitIntoClient
-  public static func .!=(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.fcmp_une_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise less-than comparison.
-  @_alwaysEmitIntoClient
-  public static func .<(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.fcmp_olt_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise less-than-or-equal-to comparison.
-  @_alwaysEmitIntoClient
-  public static func .<=(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.fcmp_ole_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise greater-than comparison.
-  @_alwaysEmitIntoClient
-  public static func .>(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.fcmp_ogt_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-  
-  /// A vector mask with the result of a pointwise greater-than-or-equal-to comparison.
-  @_alwaysEmitIntoClient
-  public static func .>=(a: Self, b: Self) -> SIMDMask<MaskStorage> {
-    SIMDMask<MaskStorage>(${MaskExt}(
-      Builtin.fcmp_oge_${Builtin}(a._storage._value, b._storage._value)
-    ))
-  }
-}
-%  if bits == 16:
-#endif
-%  end
-
-% end
-%end
diff --git a/stdlib/public/core/SIMDFloatConcreteOperations.swift.gyb b/stdlib/public/core/SIMDFloatConcreteOperations.swift.gyb
new file mode 100644
index 0000000000000..6d2acd2b6879f
--- /dev/null
+++ b/stdlib/public/core/SIMDFloatConcreteOperations.swift.gyb
@@ -0,0 +1,154 @@
+//===--- SIMDFloatConcreteOperations.swift --------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2021-2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+%{
+from SwiftIntTypes import all_integer_types
+word_bits = int(CMAKE_SIZEOF_VOID_P) * 8
+storagescalarCounts = [2,4,8,16,32,64]
+vectorscalarCounts = storagescalarCounts + [3]
+}%
+
+%for (Scalar, bits) in [('Float16',16), ('Float',32), ('Double',64)]:
+% for n in vectorscalarCounts:
+%  Vector = "SIMD" + str(n) + "<" + Scalar + ">"
+%  storageN = 4 if n == 3 else n
+%  Builtin = "Vec" + str(storageN) + "xFPIEEE" + str(bits)
+%  VecPre = "Vec" + str(storageN) + "x"
+%  MaskExt = "Builtin.sext_" + VecPre + "Int1_" + VecPre + "Int" + str(bits)
+%  if bits == 16:
+#if !((os(macOS) || targetEnvironment(macCatalyst)) && arch(x86_64))
+@available(SwiftStdlib 5.3, *)
+%  end
+extension SIMD${n} where Scalar == ${Scalar} {
+  @_alwaysEmitIntoClient @_transparent
+  internal init(_ _builtin: Builtin.${Builtin}) {
+    _storage = ${Scalar}.SIMD${storageN}Storage(_builtin)
+  }
+  
+  /// A vector with the specified scalar in all lanes.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMD${n}<${Scalar}>()
+  /// for i in result.indices {
+  ///   result[i] = scalar
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient @_transparent
+  public init(repeating scalar: ${Scalar}) {
+    let asVector = Builtin.insertelement_${Builtin}_FPIEEE${bits}_Int32(
+      Builtin.zeroInitializer(), scalar._value, Builtin.zeroInitializer()
+    )
+    let repeated = Builtin.shufflevector_${Builtin}_Vec${storageN}xInt32(
+      asVector, Builtin.zeroInitializer(), Builtin.zeroInitializer()
+    )
+%if n != 3:
+    self.init(repeated)
+%else:
+    self.init(Builtin.insertelement_${Builtin}_FPIEEE${bits}_Int32(
+      repeated, Builtin.zeroInitializer(), Int32(3)._value
+    ))
+%end
+  }
+  
+%  if n >= 4:
+  /// A vector formed by concatenating lowHalf and highHalf.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMD${n}<${Scalar}>()
+  /// for i in 0..<${n//2} {
+  ///   result[i] = lowHalf[i]
+  ///   result[${n//2}+i] = highHalf[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient @_transparent
+  public init(
+    lowHalf: SIMD${n//2}<${Scalar}>,
+    highHalf: SIMD${n//2}<${Scalar}>
+  ) {
+    self = unsafe unsafeBitCast((lowHalf, highHalf), to: Self.self)
+  }
+  
+%  end
+%{
+compares = [
+  ("==", "oeq", "equal to"),
+  ("!=", "une", "not equal to"),
+  ("<",  "olt", "less than"),
+  ("<=", "ole", "less than or equal to"),
+  (">=", "oge", "greater than or equal to"),
+  (">",  "ogt", "greater than")
+]
+}%
+%  for (op, bi, description) in compares:
+  /// Pointwise compare ${description}.
+  ///
+  /// Each lane of the result is true if that lane of a is ${description} the
+  /// corresponding lane of b, and false otherwise.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMDMask<MaskStorage>()
+  /// for i in 0..<${n} {
+  ///   result[i] = (a[i] ${op} b[i])
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient @_transparent
+  public static func .${op}(a: Self, b: Self) -> SIMDMask<MaskStorage> {
+    SIMDMask<MaskStorage>(${MaskExt}(
+      Builtin.fcmp_${bi}_${Builtin}(a._storage._value, b._storage._value)
+    ))
+  }
+  
+  /// Pointwise compare ${description}.
+  ///
+  /// Each lane of the result is true if that lane of a is ${description} b,
+  /// and false otherwise.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMDMask<MaskStorage>()
+  /// for i in 0..<${n} {
+  ///   result[i] = (a[i] ${op} b)
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient @_transparent @_disfavoredOverload
+  public static func .${op}(a: Self, b: Scalar) -> SIMDMask<MaskStorage> {
+    a .${op} Self(repeating: b)
+  }
+
+  /// Pointwise compare ${description}.
+  ///
+  /// Each lane of the result is true if a is ${description} the corresponding
+  /// lane of b, and false otherwise.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMDMask<MaskStorage>()
+  /// for i in 0..<${n} {
+  ///   result[i] = (a ${op} b[i])
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient @_transparent @_disfavoredOverload
+  public static func .${op}(a: Scalar, b: Self) -> SIMDMask<MaskStorage> {
+    Self(repeating: a) .${op} b
+  }
+
+%  end
+}
+%  if bits == 16:
+#endif
+%  end
+
+% end
+%end
diff --git a/stdlib/public/core/SIMDIntegerConcreteOperations.swift.gyb b/stdlib/public/core/SIMDIntegerConcreteOperations.swift.gyb
new file mode 100644
index 0000000000000..963dfa7510371
--- /dev/null
+++ b/stdlib/public/core/SIMDIntegerConcreteOperations.swift.gyb
@@ -0,0 +1,163 @@
+//===--- SIMDIntegerConcreteOperations.swift ------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2021-2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+%{
+from SwiftIntTypes import all_integer_types
+word_bits = int(CMAKE_SIZEOF_VOID_P) * 8
+storagescalarCounts = [2,4,8,16,32,64]
+vectorscalarCounts = storagescalarCounts + [3]
+}%
+
+%for int in all_integer_types(word_bits):
+% Scalar = int.stdlib_name
+% for n in vectorscalarCounts:
+%  Vector = "SIMD" + str(n) + "<" + Scalar + ">"
+%  storageN = 4 if n == 3 else n
+%  s = "s" if int.is_signed else "u"
+%  Builtin = "Vec" + str(storageN) + "xInt" + str(int.bits)
+%  MaskExt = "Builtin.sext_Vec" + str(storageN) + "xInt1_" + Builtin
+extension SIMD${n} where Scalar == ${Scalar} {
+  @_alwaysEmitIntoClient @_transparent
+  internal init(_ _builtin: Builtin.${Builtin}) {
+    _storage = ${Scalar}.SIMD${storageN}Storage(_builtin)
+  }
+  
+  /// A vector with the specified scalar in all lanes.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMD${n}<${Scalar}>()
+  /// for i in result.indices {
+  ///   result[i] = scalar
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient @_transparent
+  public init(repeating scalar: ${Scalar}) {
+    let asVector = Builtin.insertelement_${Builtin}_Int${int.bits}_Int32(
+      Builtin.zeroInitializer(), scalar._value, Builtin.zeroInitializer()
+    )
+    let repeated = Builtin.shufflevector_${Builtin}_Vec${storageN}xInt32(
+      asVector, Builtin.zeroInitializer(), Builtin.zeroInitializer()
+    )
+%   if n != 3:
+    self.init(repeated)
+%   else:
+    self.init(Builtin.insertelement_${Builtin}_Int${int.bits}_Int32(
+      repeated, Builtin.zeroInitializer(), Int32(3)._value
+    ))
+%   end
+  }
+  
+%  if n >= 4:
+  /// A vector formed by concatenating lowHalf and highHalf.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMD${n}<${Scalar}>()
+  /// for i in 0..<${n//2} {
+  ///   result[i] = lowHalf[i]
+  ///   result[${n//2}+i] = highHalf[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient @_transparent
+  public init(
+    lowHalf: SIMD${n//2}<${Scalar}>,
+    highHalf: SIMD${n//2}<${Scalar}>
+  ) {
+    self = unsafe unsafeBitCast((lowHalf, highHalf), to: Self.self)
+  }
+  
+%  end
+  /// A vector mask with the result of a pointwise equality comparison.
+  @_alwaysEmitIntoClient
+  public static func .==(a: Self, b: Self) -> SIMDMask<MaskStorage> {
+    SIMDMask<MaskStorage>(${MaskExt}(
+      Builtin.cmp_eq_${Builtin}(a._storage._value, b._storage._value)
+    ))
+  }
+  
+  /// A vector mask with the result of a pointwise inequality comparison.
+  @_alwaysEmitIntoClient
+  public static func .!=(a: Self, b: Self) -> SIMDMask<MaskStorage> {
+    SIMDMask<MaskStorage>(${MaskExt}(
+      Builtin.cmp_ne_${Builtin}(a._storage._value, b._storage._value)
+    ))
+  }
+  
+  /// A vector mask with the result of a pointwise less-than comparison.
+  @_alwaysEmitIntoClient
+  public static func .<(a: Self, b: Self) -> SIMDMask<MaskStorage> {
+    SIMDMask<MaskStorage>(${MaskExt}(
+      Builtin.cmp_${s}lt_${Builtin}(a._storage._value, b._storage._value)
+    ))
+  }
+  
+  /// A vector mask with the result of a pointwise less-than-or-equal-to comparison.
+  @_alwaysEmitIntoClient
+  public static func .<=(a: Self, b: Self) -> SIMDMask<MaskStorage> {
+    SIMDMask<MaskStorage>(${MaskExt}(
+      Builtin.cmp_${s}le_${Builtin}(a._storage._value, b._storage._value)
+    ))
+  }
+  
+  /// A vector mask with the result of a pointwise greater-than comparison.
+  @_alwaysEmitIntoClient
+  public static func .>(a: Self, b: Self) -> SIMDMask<MaskStorage> {
+    SIMDMask<MaskStorage>(${MaskExt}(
+      Builtin.cmp_${s}gt_${Builtin}(a._storage._value, b._storage._value)
+    ))
+  }
+  
+  /// A vector mask with the result of a pointwise greater-than-or-equal-to comparison.
+  @_alwaysEmitIntoClient
+  public static func .>=(a: Self, b: Self) -> SIMDMask<MaskStorage> {
+    SIMDMask<MaskStorage>(${MaskExt}(
+      Builtin.cmp_${s}ge_${Builtin}(a._storage._value, b._storage._value)
+    ))
+  }
+    
+  /// The wrapping sum of two vectors.
+  @_alwaysEmitIntoClient
+  public static func &+(a: Self, b: Self) -> Self {
+    Self(Builtin.add_${Builtin}(a._storage._value, b._storage._value))
+  }
+    
+  /// The wrapping difference of two vectors.
+  @_alwaysEmitIntoClient
+  public static func &-(a: Self, b: Self) -> Self {
+    Self(Builtin.sub_${Builtin}(a._storage._value, b._storage._value))
+  }
+    
+  /// The pointwise wrapping product of two vectors.
+  @_alwaysEmitIntoClient
+  public static func &*(a: Self, b: Self) -> Self {
+    Self(Builtin.mul_${Builtin}(a._storage._value, b._storage._value))
+  }
+        
+  /// Updates the left hand side with the wrapping sum of the two
+  /// vectors.
+  @_alwaysEmitIntoClient
+  public static func &+=(a: inout Self, b: Self) { a = a &+ b }
+    
+  /// Updates the left hand side with the wrapping difference of the two
+  /// vectors.
+  @_alwaysEmitIntoClient
+  public static func &-=(a: inout Self, b: Self) { a = a &- b }
+    
+  /// Updates the left hand side with the pointwise wrapping product of two
+  /// vectors.
+  @_alwaysEmitIntoClient
+  public static func &*=(a: inout Self, b: Self) { a = a &* b }
+}
+
+% end
+%end
diff --git a/stdlib/public/core/SIMDMaskConcreteOperations.swift.gyb b/stdlib/public/core/SIMDMaskConcreteOperations.swift.gyb
new file mode 100644
index 0000000000000..58ad6e2f2aa75
--- /dev/null
+++ b/stdlib/public/core/SIMDMaskConcreteOperations.swift.gyb
@@ -0,0 +1,214 @@
+//===--- SIMDMaskConcreteOperations.swift ---------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2021-2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+%{
+from SwiftIntTypes import all_signed_types
+word_bits = int(CMAKE_SIZEOF_VOID_P) * 8
+storagescalarCounts = [2,4,8,16,32,64]
+vectorscalarCounts = storagescalarCounts + [3]
+}%
+
+%for int in all_signed_types(word_bits):
+% Scalar = int.stdlib_name
+% for n in vectorscalarCounts:
+%  Vector = "SIMD" + str(n) + "<" + Scalar + ">"
+%  storageN = 4 if n == 3 else n
+%  s = "s"
+%  Builtin = "Vec" + str(storageN) + "xInt" + str(int.bits)
+%  MaskExt = "Builtin.sext_Vec" + str(storageN) + "xInt1_" + Builtin
+extension SIMDMask where Storage == ${Vector} {
+  @_alwaysEmitIntoClient @_transparent
+  internal init(_ _builtin: Builtin.${Builtin}) {
+    _storage = ${Vector}(_builtin)
+  }
+  
+  @_alwaysEmitIntoClient @_transparent
+  public init(repeating scalar: Bool) {
+    _storage = ${Vector}(repeating: scalar ? -1 : 0)
+  }
+  
+  @_alwaysEmitIntoClient
+  internal static var allTrue: Self {
+    let zero = ${Vector}()
+    return zero .== zero
+  }
+  
+  /// A vector mask that is the pointwise logical negation of the input.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMDMask<${Vector}>()
+  /// for i in result.indices {
+  ///   result[i] = !a[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient
+  public static prefix func .!(a: Self) -> Self {
+    a .^ .allTrue
+  }
+    
+  /// A vector mask that is the pointwise logical conjunction of the inputs.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMDMask<${Vector}>()
+  /// for i in result.indices {
+  ///   result[i] = a[i] && b[i]
+  /// }
+  /// ```
+  ///
+  /// Note that unlike the scalar `&&` operator, the SIMD `.&` operator
+  /// always fully evaluates both arguments.
+  @_alwaysEmitIntoClient
+  public static func .&(a: Self, b: Self) -> Self {
+    Self(${Vector}(Builtin.and_${Builtin}(
+      a._storage._storage._value,
+      b._storage._storage._value
+    )))
+  }
+    
+  /// Replaces `a` with the pointwise logical conjunction of `a` and `b`.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// for i in a.indices {
+  ///   a[i] = a[i] && b[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient
+  public static func .&=(a: inout Self, b: Self) {
+    a = a .& b
+  }
+      
+  /// A vector mask that is the pointwise exclusive or of the inputs.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMDMask<${Vector}>()
+  /// for i in result.indices {
+  ///   result[i] = a[i] != b[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient
+  public static func .^(a: Self, b: Self) -> Self {
+    Self(${Vector}(Builtin.xor_${Builtin}(
+      a._storage._storage._value,
+      b._storage._storage._value
+    )))
+  }
+    
+  /// Replaces `a` with the pointwise exclusive or of `a` and `b`.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// for i in a.indices {
+  ///   a[i] = a[i] != b[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient
+  public static func .^=(a: inout Self, b: Self) {
+    a = a .^ b
+  }
+      
+  /// A vector mask that is the pointwise logical disjunction of the inputs.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMDMask<${Vector}>()
+  /// for i in result.indices {
+  ///   result[i] = a[i] || b[i]
+  /// }
+  /// ```
+  ///
+  /// Note that unlike the scalar `||` operator, the SIMD `.|` operator
+  /// always fully evaluates both arguments.
+  @_alwaysEmitIntoClient
+  public static func .|(a: Self, b: Self) -> Self {
+    Self(${Vector}(Builtin.or_${Builtin}(
+      a._storage._storage._value,
+      b._storage._storage._value
+    )))
+  }
+    
+  /// Replaces `a` with the pointwise logical disjunction of `a` and `b`.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// for i in a.indices {
+  ///   a[i] = a[i] || b[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient
+  public static func .|=(a: inout Self, b: Self) {
+    a = a .| b
+  }
+    
+  /// A vector mask with the result of a pointwise equality comparison.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMDMask<${Vector}>()
+  /// for i in result.indices {
+  ///   result[i] = a[i] == b[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient
+  public static func .==(a: Self, b: Self) -> Self {
+    .!(a .^ b)
+  }
+  
+  /// A vector mask with the result of a pointwise inequality comparison.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMDMask<${Vector}>()
+  /// for i in result.indices {
+  ///   result[i] = a[i] != b[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient
+  public static func .!=(a: Self, b: Self) -> Self {
+    a .^ b
+  }
+    
+  /// Replaces elements of this vector with elements of `other` in the lanes
+  /// where `mask` is `true`.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// for i in indices {
+  ///   if mask[i] { self[i] = other[i] }
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient
+  public mutating func replace(with other: Self, where mask: Self) {
+    self = replacing(with: other, where: mask)
+  }
+    
+  /// Returns a copy of this vector, with elements replaced by elements of
+  /// `other` in the lanes where `mask` is `true`.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = Self()
+  /// for i in indices {
+  ///   result[i] = mask[i] ? other[i] : self[i]
+  /// }
+  /// ```
+  @_alwaysEmitIntoClient
+  public func replacing(with other: Self, where mask: Self) -> Self {
+    (self .& .!mask) .| (other .& mask)
+  }
+}
+
+% end
+%end
diff --git a/stdlib/public/core/SIMDVector.swift b/stdlib/public/core/SIMDVector.swift
index 77ad4a8c8b5c3..ee83084878b2b 100644
--- a/stdlib/public/core/SIMDVector.swift
+++ b/stdlib/public/core/SIMDVector.swift
@@ -111,7 +111,15 @@ extension SIMD {
     return 0 ..< scalarCount
   }
   
-  /// A vector with the specified value in all lanes.
+  /// A vector with the specified scalar in all lanes.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = Self()
+  /// for i in result.indices {
+  ///   result[i] = scalar
+  /// }
+  /// ```
   @_transparent
   public init(repeating value: Scalar) {
     self.init()
diff --git a/stdlib/public/core/SIMDVectorTypes.swift.gyb b/stdlib/public/core/SIMDVectorTypes.swift.gyb
index 671519e2fd549..24741b8668ef1 100644
--- a/stdlib/public/core/SIMDVectorTypes.swift.gyb
+++ b/stdlib/public/core/SIMDVectorTypes.swift.gyb
@@ -88,7 +88,16 @@ public struct SIMD${n}<Scalar>: SIMD where Scalar: SIMDScalar {
 %  end
 % end
 % if n >= 4:
-  /// Creates a new vector from two half-length vectors.
+  /// A vector formed by concatenating lowHalf and highHalf.
+  ///
+  /// Equivalent to:
+  /// ```
+  /// var result = SIMD${n}<Scalar>()
+  /// for i in 0..<${n//2} {
+  ///   result[i] = lowHalf[i]
+  ///   result[${n//2}+i] = highHalf[i]
+  /// }
+  /// ```
   @_transparent
   public init(lowHalf: SIMD${n//2}<Scalar>, highHalf: SIMD${n//2}<Scalar>) {
     self.init()
diff --git a/stdlib/public/core/Sendable.swift b/stdlib/public/core/Sendable.swift
index d843eaefaaaad..bbc47f43741dd 100644
--- a/stdlib/public/core/Sendable.swift
+++ b/stdlib/public/core/Sendable.swift
@@ -10,7 +10,55 @@
 //
 //===----------------------------------------------------------------------===//
 
-/// A type `T` whose metatype `T.Type` is `Sendable`.
+/// A type whose metatype can be shared across arbitrary concurrent contexts
+/// without introducing a risk of data races. When a generic type `T` conforms
+/// to `SendableMetatype`, its metatype `T.Type` conforms to `Sendable`. All
+/// concrete types implicitly conform to the `SendableMetatype` protocol, so its
+/// primary purpose is in generic code to prohibit the use of isolated
+/// conformances along with the generic type.
+///
+/// A generic type `T` will need a `SendableMetatype` conformance when its
+/// metatype is shared across concurrency boundaries. For example,
+///
+///     protocol P {
+///       static func f()
+///     }
+///
+///     func useFromAnotherTask<T: P>(_: T.Type) {
+///       Task { @concurrent in
+///         T.f()   // error: capturing non-Sendable type `T.Type` in a concurrently-executing task
+///       }
+///     }
+///
+/// The potential data race above would occur when `useFromAnotherTask` is
+/// provided with an isolated conformance to `P`. For example:
+///
+///     @MainActor
+///     class MyModel: @MainActor P {
+///       /* implicitly @MainActor */
+///       static func f() {
+///         /* on the main actor */
+///       }
+///     }
+///
+///     useFromAnotherTask(MyModel.self)
+///
+/// Here, the error within the body of `useFromAnotherTask` is preventing the
+/// isolated conformance from leaving the current task and actor. The signature
+/// of `useFromAnotherTask` can be adjusted to introduce a requirement on
+/// `SendableMetatype`:
+///
+///     func useFromAnotherTask<T: P & SendableMetatype>(_: T.Type) {
+///       Task { @concurrent in
+///         T.f()   // error: okay, T.Type is Sendable
+///       }
+///     }
+///
+///     useFromAnotherTask(MyModel.self) // error: cannot use main-actor-isolated conformance `MyModel: P` for a `SendableMetatype`-conforming type parameter `T`
+///
+/// The `Sendable` protocol inherits from `SendableMetatype`, so any generic
+/// type `T` with a requirement `T: Sendable` will have the implied requirement
+/// `T: SendableMetatype`.
 @_marker public protocol SendableMetatype: ~Copyable, ~Escapable { }
 
 /// A thread-safe type whose values can be shared across arbitrary concurrent
@@ -135,6 +183,9 @@
 /// ### Sendable Metatypes
 ///
 /// Metatypes such as `Int.Type` implicitly conform to the `Sendable` protocol.
+/// For a generic type `T`, its metatype `T.Type` does not necessarily conform
+/// to `Sendable`. Please see the `SendableMetatype` protocol for more
+/// information.
 @_marker public protocol Sendable: SendableMetatype, ~Copyable, ~Escapable { }
 
 ///
diff --git a/stdlib/public/core/Sequence.swift b/stdlib/public/core/Sequence.swift
index e34bb9d8df267..5ae2e1addeaaa 100644
--- a/stdlib/public/core/Sequence.swift
+++ b/stdlib/public/core/Sequence.swift
@@ -705,6 +705,7 @@ extension Sequence {
     return Array(result)
   }
 
+#if !$Embedded
   // ABI-only entrypoint for the rethrows version of map, which has been
   // superseded by the typed-throws version. Expressed as "throws", which is
   // ABI-compatible with "rethrows".
@@ -716,6 +717,7 @@ extension Sequence {
   ) throws -> [T] {
     try map(transform)
   }
+#endif
 
   /// Returns an array containing, in order, the elements of the sequence
   /// that satisfy the given predicate.
diff --git a/stdlib/public/core/SetBridging.swift b/stdlib/public/core/SetBridging.swift
index 458b1d30424bf..e07c571599209 100644
--- a/stdlib/public/core/SetBridging.swift
+++ b/stdlib/public/core/SetBridging.swift
@@ -103,12 +103,12 @@ final internal class _SwiftSetNSEnumerator<Element: Hashable>
 
   @objc
   internal func nextObject() -> AnyObject? {
-    if unsafe nextBucket == endBucket {
+    if nextBucket == endBucket {
       return nil
     }
-    let bucket = unsafe nextBucket
+    let bucket = nextBucket
     unsafe nextBucket = base.hashTable.occupiedBucket(after: nextBucket)
-    return unsafe self.bridgedElement(at: bucket)
+    return self.bridgedElement(at: bucket)
   }
 
   @objc(countByEnumeratingWithState:objects:count:)
@@ -124,7 +124,7 @@ final internal class _SwiftSetNSEnumerator<Element: Hashable>
       unsafe theState.mutationsPtr = _fastEnumerationStorageMutationsPtr
     }
 
-    if unsafe nextBucket == endBucket {
+    if nextBucket == endBucket {
       unsafe state.pointee = theState
       return 0
     }
@@ -276,10 +276,10 @@ final internal class _SwiftDeferredNSSet<Element: Hashable>
 
     var stored = 0
     for i in 0..<count {
-      if unsafe bucket == endBucket { break }
+      if bucket == endBucket { break }
       unsafe unmanagedObjects[i] = unsafe bridgedElements[bucket]
       stored += 1
-      unsafe bucket = unsafe hashTable.occupiedBucket(after: bucket)
+      bucket = unsafe hashTable.occupiedBucket(after: bucket)
     }
     unsafe theState.extra.0 = CUnsignedLong(bucket.offset)
     unsafe state.pointee = theState
diff --git a/stdlib/public/core/SetBuilder.swift b/stdlib/public/core/SetBuilder.swift
index b9dcd766a93a3..4bd3d16997501 100644
--- a/stdlib/public/core/SetBuilder.swift
+++ b/stdlib/public/core/SetBuilder.swift
@@ -33,7 +33,7 @@ struct _SetBuilder<Element: Hashable> {
   public mutating func add(member: Element) {
     _precondition(_target.count < _requestedCount,
       "Can't add more members than promised")
-    _target._unsafeInsertNew(member)
+    unsafe _target._unsafeInsertNew(member)
   }
 
   @inlinable
diff --git a/stdlib/public/core/SetCasting.swift b/stdlib/public/core/SetCasting.swift
index d39aba31daf32..76208d91649c6 100644
--- a/stdlib/public/core/SetCasting.swift
+++ b/stdlib/public/core/SetCasting.swift
@@ -29,7 +29,7 @@ extension Set {
     } else {
       for m in source {
         guard let member = transform(m) else { return nil }
-        target._unsafeInsertNew(member)
+        unsafe target._unsafeInsertNew(member)
       }
     }
     self.init(_native: target)
diff --git a/stdlib/public/core/SetStorage.swift b/stdlib/public/core/SetStorage.swift
index 9705a7fee064e..7ca71e27ec012 100644
--- a/stdlib/public/core/SetStorage.swift
+++ b/stdlib/public/core/SetStorage.swift
@@ -289,11 +289,11 @@ final internal class _SetStorage<Element: Hashable>
       "Invalid fast enumeration state")
     var stored = 0
     for i in 0..<count {
-      if unsafe bucket == endBucket { break }
+      if bucket == endBucket { break }
       let element = unsafe _elements[bucket.offset]
       unsafe unmanagedObjects[i] = _bridgeAnythingToObjectiveC(element)
       stored += 1
-      unsafe bucket = unsafe hashTable.occupiedBucket(after: bucket)
+      bucket = unsafe hashTable.occupiedBucket(after: bucket)
     }
     unsafe theState.extra.0 = CUnsignedLong(bucket.offset)
     unsafe state.pointee = theState
@@ -370,7 +370,7 @@ extension _SetStorage {
       bucketCount._builtinWordValue, Element.self)
 
     let metadataAddr = unsafe Builtin.projectTailElems(storage, _HashTable.Word.self)
-    let elementsAddr = unsafe Builtin.getTailAddr_Word(
+    let elementsAddr = Builtin.getTailAddr_Word(
       metadataAddr, wordCount._builtinWordValue, _HashTable.Word.self,
       Element.self)
     unsafe storage._count = 0
diff --git a/stdlib/public/core/SetVariant.swift b/stdlib/public/core/SetVariant.swift
index b6cffd5341547..1ba9ae55fdc44 100644
--- a/stdlib/public/core/SetVariant.swift
+++ b/stdlib/public/core/SetVariant.swift
@@ -287,7 +287,7 @@ extension Set._Variant {
       return (false, unsafe asNative.uncheckedElement(at: bucket))
     }
     let isUnique = self.isUniquelyReferenced()
-    unsafe asNative.insertNew(element, at: bucket, isUnique: isUnique)
+    asNative.insertNew(element, at: bucket, isUnique: isUnique)
     return (true, element)
   }
 
@@ -305,7 +305,7 @@ extension Set._Variant {
     }
 #endif
     let isUnique = isUniquelyReferenced()
-    let bucket = unsafe asNative.validatedBucket(for: index)
+    let bucket = asNative.validatedBucket(for: index)
     return unsafe asNative.uncheckedRemove(at: bucket, isUnique: isUnique)
   }
 
diff --git a/stdlib/public/core/SmallString.swift b/stdlib/public/core/SmallString.swift
index 87420bc3d277b..c7819011644b4 100644
--- a/stdlib/public/core/SmallString.swift
+++ b/stdlib/public/core/SmallString.swift
@@ -79,8 +79,11 @@ internal struct _SmallString {
 extension _SmallString {
   @inlinable @inline(__always)
   internal static var capacity: Int {
-#if _pointerBitWidth(_32) || _pointerBitWidth(_16)
+#if os(watchOS) && _pointerBitWidth(_32)
     return 10
+#elseif _pointerBitWidth(_32) || _pointerBitWidth(_16)
+    // Note: changed from 10 for contiguous storage.
+    return 8
 #elseif os(Android) && arch(arm64)
     return 14
 #elseif _pointerBitWidth(_64)
@@ -90,6 +93,15 @@ extension _SmallString {
 #endif
   }
 
+  @_alwaysEmitIntoClient @inline(__always)
+  internal static func contiguousCapacity() -> Int {
+#if os(watchOS) && _pointerBitWidth(_32)
+    return capacity &- 2
+#else
+    return capacity
+#endif
+  }
+
   // Get an integer equivalent to the _StringObject.discriminatedObjectRawBits
   // computed property.
   @inlinable @inline(__always)
@@ -147,7 +159,7 @@ extension _SmallString {
     var copy = self
     unsafe withUnsafeBytes(of: &copy._storage) {
       unsafe _internalInvariant(
-        $0[count..<_SmallString.capacity].allSatisfy { unsafe $0 == 0 })
+        $0[count..<_SmallString.capacity].allSatisfy { $0 == 0 })
     }
   }
   #endif // INTERNAL_CHECKS_ENABLED
diff --git a/stdlib/public/core/Sort.swift b/stdlib/public/core/Sort.swift
index ae4a5a3fbeb43..cd8b07faf2211 100644
--- a/stdlib/public/core/Sort.swift
+++ b/stdlib/public/core/Sort.swift
@@ -530,10 +530,10 @@ extension UnsafeMutableBufferPointer {
     buffer: UnsafeMutablePointer<Element>,
     by areInIncreasingOrder: (Element, Element) throws -> Bool
   ) rethrows -> Bool {
-    unsafe _internalInvariant(runs[i - 1].upperBound == runs[i].lowerBound)
-    let low = unsafe runs[i - 1].lowerBound
-    let middle = unsafe runs[i].lowerBound
-    let high = unsafe runs[i].upperBound
+    _internalInvariant(runs[i - 1].upperBound == runs[i].lowerBound)
+    let low = runs[i - 1].lowerBound
+    let middle = runs[i].lowerBound
+    let high = runs[i].upperBound
     
     try unsafe _merge(
       low: baseAddress! + low,
@@ -542,8 +542,8 @@ extension UnsafeMutableBufferPointer {
       buffer: buffer,
       by: areInIncreasingOrder)
     
-    unsafe runs[i - 1] = unsafe low..<high
-    unsafe runs.remove(at: i)
+    runs[i - 1] = low..<high
+    runs.remove(at: i)
 
     return true
   }
@@ -588,30 +588,30 @@ extension UnsafeMutableBufferPointer {
     // for the entirety of `runs`.
     
     // The invariant is always in place for a single element.
-    while unsafe runs.count > 1 {
-      var lastIndex = unsafe runs.count - 1
+    while runs.count > 1 {
+      var lastIndex = runs.count - 1
       
       // Check for the three invariant-breaking conditions, and break out of
       // the while loop if none are met.
-      if unsafe lastIndex >= 3 &&
+      if lastIndex >= 3 &&
         (runs[lastIndex - 3].count <=
           runs[lastIndex - 2].count + runs[lastIndex - 1].count)
       {
         // Second-to-last three runs do not follow W > X + Y.
         // Always merge Y with the smaller of X or Z.
-        if unsafe runs[lastIndex - 2].count < runs[lastIndex].count {
+        if runs[lastIndex - 2].count < runs[lastIndex].count {
           lastIndex -= 1
         }
-      } else if unsafe lastIndex >= 2 &&
+      } else if lastIndex >= 2 &&
         (runs[lastIndex - 2].count <=
           runs[lastIndex - 1].count + runs[lastIndex].count)
       {
         // Last three runs do not follow X > Y + Z.
         // Always merge Y with the smaller of X or Z.
-        if unsafe runs[lastIndex - 2].count < runs[lastIndex].count {
+        if runs[lastIndex - 2].count < runs[lastIndex].count {
           lastIndex -= 1
         }
-      } else if unsafe runs[lastIndex - 1].count <= runs[lastIndex].count {
+      } else if runs[lastIndex - 1].count <= runs[lastIndex].count {
         // Last two runs do not follow Y > Z, so merge Y and Z.
         // This block is intentionally blank--the merge happens below.
       } else {
@@ -645,7 +645,7 @@ extension UnsafeMutableBufferPointer {
     buffer: UnsafeMutablePointer<Element>,
     by areInIncreasingOrder: (Element, Element) throws -> Bool
   ) rethrows -> Bool {
-    while unsafe runs.count > 1 {
+    while runs.count > 1 {
       try unsafe _mergeRuns(
         &runs, at: runs.count - 1, buffer: buffer, by: areInIncreasingOrder)
     }
@@ -675,9 +675,9 @@ extension UnsafeMutableBufferPointer {
     //
     // There's no need to set the initialized count within the initializing
     // closure, since the buffer is guaranteed to be uninitialized at exit.
-    _ = try unsafe Array<Element>(_unsafeUninitializedCapacity: count / 2) {
+    _ = try unsafe Array<Element>(unsafeUninitializedCapacity: count / 2) {
       buffer, _ in
-      var runs: [Range<Index>] = unsafe []
+      var runs: [Range<Index>] = []
       
       var start = startIndex
       while start < endIndex {
@@ -690,24 +690,24 @@ extension UnsafeMutableBufferPointer {
         
         // If the current run is shorter than the minimum length, use the
         // insertion sort to extend it.
-        if unsafe end < endIndex && end - start < minimumRunLength {
+        if end < endIndex && end - start < minimumRunLength {
           let newEnd = Swift.min(endIndex, start + minimumRunLength)
           try unsafe _insertionSort(
             within: start..<newEnd, sortedEnd: end, by: areInIncreasingOrder)
-          unsafe end = newEnd
+          end = newEnd
         }
         
         // Append this run and merge down as needed to maintain the `runs`
         // invariants.
-        unsafe runs.append(start..<end)
+        runs.append(start..<end)
         try unsafe _mergeTopRuns(
           &runs, buffer: buffer.baseAddress!, by: areInIncreasingOrder)
-        start = unsafe end
+        start = end
       }
       
       try unsafe _finalizeRuns(
         &runs, buffer: buffer.baseAddress!, by: areInIncreasingOrder)
-      unsafe _internalInvariant(runs.count == 1, "Didn't complete final merge")
+      _internalInvariant(runs.count == 1, "Didn't complete final merge")
     }
   }
 }
diff --git a/stdlib/public/core/Span/MutableRawSpan.swift b/stdlib/public/core/Span/MutableRawSpan.swift
index e5c4d8f523ed7..9e52138367dd5 100644
--- a/stdlib/public/core/Span/MutableRawSpan.swift
+++ b/stdlib/public/core/Span/MutableRawSpan.swift
@@ -10,11 +10,16 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if SPAN_COMPATIBILITY_STUB
+import Swift
+#endif
+
 // A MutableRawSpan represents a span of memory which
 // contains initialized `Element` instances.
 @safe
 @frozen
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 public struct MutableRawSpan: ~Copyable & ~Escapable {
   @usableFromInline
   internal let _pointer: UnsafeMutableRawPointer?
@@ -22,13 +27,21 @@ public struct MutableRawSpan: ~Copyable & ~Escapable {
   @usableFromInline
   internal let _count: Int
 
+  @unsafe
   @_alwaysEmitIntoClient
   internal func _start() -> UnsafeMutableRawPointer {
     unsafe _pointer._unsafelyUnwrappedUnchecked
   }
 
+  @_alwaysEmitIntoClient
+  @inline(__always)
+  @lifetime(immortal)
+  public init() {
+    unsafe _pointer = nil
+    _count = 0
+  }
+
   @unsafe
-  @_unsafeNonescapableResult
   @_alwaysEmitIntoClient
   @lifetime(borrow pointer)
   internal init(
@@ -40,10 +53,12 @@ public struct MutableRawSpan: ~Copyable & ~Escapable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableRawSpan: @unchecked Sendable {}
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableRawSpan {
 
   @unsafe
@@ -116,7 +131,8 @@ extension MutableRawSpan {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableRawSpan {
   @_alwaysEmitIntoClient
   public var byteCount: Int { _count }
@@ -130,7 +146,8 @@ extension MutableRawSpan {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableRawSpan {
 
   @_alwaysEmitIntoClient
@@ -155,19 +172,21 @@ extension MutableRawSpan {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
 
   @_alwaysEmitIntoClient
   @lifetime(borrow mutableRawSpan)
   public init(_mutableRawSpan mutableRawSpan: borrowing MutableRawSpan) {
-    let (start, count) = unsafe (mutableRawSpan._start(), mutableRawSpan._count)
-    let span = unsafe RawSpan(_unsafeStart: start, byteCount: count)
+    let (start, count) = unsafe (mutableRawSpan._pointer, mutableRawSpan._count)
+    let span = unsafe RawSpan(_unchecked: start, byteCount: count)
     self = unsafe _overrideLifetime(span, borrowing: mutableRawSpan)
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableRawSpan {
 
   public var bytes: RawSpan {
@@ -191,7 +210,7 @@ extension MutableRawSpan {
 
   @unsafe
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
+  @lifetime(&self)
   public mutating func _unsafeMutableView<T: BitwiseCopyable>(
     as type: T.Type
   ) -> MutableSpan<T> {
@@ -203,7 +222,8 @@ extension MutableRawSpan {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableRawSpan {
 
   /// Returns a new instance of the given type, constructed from the raw memory
@@ -226,7 +246,7 @@ extension MutableRawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   public func unsafeLoad<T>(
-    fromByteOffset offset: Int = 0, as: T.Type
+    fromByteOffset offset: Int = 0, as type: T.Type
   ) -> T {
     _precondition(
       UInt(bitPattern: offset) <= UInt(bitPattern: _count) &&
@@ -257,7 +277,7 @@ extension MutableRawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   public func unsafeLoad<T>(
-    fromUncheckedByteOffset offset: Int, as: T.Type
+    fromUncheckedByteOffset offset: Int, as type: T.Type
   ) -> T {
     unsafe _start().load(fromByteOffset: offset, as: T.self)
   }
@@ -281,7 +301,7 @@ extension MutableRawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   public func unsafeLoadUnaligned<T: BitwiseCopyable>(
-    fromByteOffset offset: Int = 0, as: T.Type
+    fromByteOffset offset: Int = 0, as type: T.Type
   ) -> T {
     _precondition(
       UInt(bitPattern: offset) <= UInt(bitPattern: _count) &&
@@ -311,7 +331,7 @@ extension MutableRawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   public func unsafeLoadUnaligned<T: BitwiseCopyable>(
-    fromUncheckedByteOffset offset: Int, as: T.Type
+    fromUncheckedByteOffset offset: Int, as type: T.Type
   ) -> T {
     unsafe _start().loadUnaligned(fromByteOffset: offset, as: T.self)
   }
@@ -339,100 +359,9 @@ extension MutableRawSpan {
   }
 }
 
-//MARK: copyMemory
-@available(SwiftStdlib 6.2, *)
-extension MutableRawSpan {
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update<S: Sequence>(
-    from source: S
-  ) -> (unwritten: S.Iterator, byteOffset: Int) where S.Element: BitwiseCopyable {
-    var iterator = source.makeIterator()
-    let offset = update(from: &iterator)
-    return (iterator, offset)
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update<Element: BitwiseCopyable>(
-    from elements: inout some IteratorProtocol<Element>
-  ) -> Int {
-    var offset = 0
-    while offset + MemoryLayout<Element>.stride <= _count {
-      guard let element = elements.next() else { break }
-      unsafe storeBytes(
-        of: element, toUncheckedByteOffset: offset, as: Element.self
-      )
-      offset &+= MemoryLayout<Element>.stride
-    }
-    return offset
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update<C: Collection>(
-    fromContentsOf source: C
-  ) -> Int where C.Element: BitwiseCopyable {
-    let newOffset = source.withContiguousStorageIfAvailable {
-      self.update(fromContentsOf: unsafe RawSpan(_unsafeElements: $0))
-    }
-    if let newOffset { return newOffset }
-
-    var elements = source.makeIterator()
-    let lastOffset = update(from: &elements)
-    _precondition(
-      elements.next() == nil,
-      "destination span cannot contain every element from source."
-    )
-    return lastOffset
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update<Element: BitwiseCopyable>(
-    fromContentsOf source: Span<Element>
-  ) -> Int {
-//    update(from: source.bytes)
-    unsafe source.withUnsafeBytes {
-      unsafe update(fromContentsOf: $0)
-    }
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update<Element: BitwiseCopyable>(
-    fromContentsOf source: borrowing MutableSpan<Element>
-  ) -> Int {
-//    update(from: source.span.bytes)
-    unsafe source.withUnsafeBytes {
-      unsafe update(fromContentsOf: $0)
-    }
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    fromContentsOf source: RawSpan
-  ) -> Int {
-    if source.byteCount == 0 { return 0 }
-    unsafe source.withUnsafeBytes {
-      unsafe _start().copyMemory(from: $0.baseAddress!, byteCount: $0.count)
-    }
-    return source.byteCount
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    fromContentsOf source: borrowing MutableRawSpan
-  ) -> Int {
-    update(fromContentsOf: source.bytes)
-  }
-}
-
 // MARK: sub-spans
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableRawSpan {
 
   /// Constructs a new span over the items within the supplied range of
@@ -449,14 +378,32 @@ extension MutableRawSpan {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(_ bounds: Range<Int>) -> Self {
+    _precondition(
+      UInt(bitPattern: bounds.lowerBound) <= UInt(bitPattern: _count) &&
+      UInt(bitPattern: bounds.upperBound) <= UInt(bitPattern: _count),
+      "Index range out of bounds"
+    )
+    return unsafe _mutatingExtracting(unchecked: bounds)
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
   mutating public func extracting(_ bounds: Range<Int>) -> Self {
+    _mutatingExtracting(bounds)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(_ bounds: Range<Int>) -> Self {
     _precondition(
       UInt(bitPattern: bounds.lowerBound) <= UInt(bitPattern: _count) &&
       UInt(bitPattern: bounds.upperBound) <= UInt(bitPattern: _count),
       "Index range out of bounds"
     )
-    return unsafe extracting(unchecked: bounds)
+    return unsafe _consumingExtracting(unchecked: bounds)
   }
 
   /// Constructs a new span over the items within the supplied range of
@@ -476,13 +423,30 @@ extension MutableRawSpan {
   /// - Complexity: O(1)
   @unsafe
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(unchecked bounds: Range<Int>) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(unchecked bounds: Range<Int>) -> Self {
     let newStart = unsafe _pointer?.advanced(by: bounds.lowerBound)
     let newSpan = unsafe Self(_unchecked: newStart, byteCount: bounds.count)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
   }
 
+  @unsafe
+  @available(*, deprecated, renamed: "_mutatingExtracting(unchecked:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(unchecked bounds: Range<Int>) -> Self {
+    unsafe _mutatingExtracting(unchecked: bounds)
+  }
+
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(unchecked bounds: Range<Int>) -> Self {
+    let newStart = unsafe _pointer?.advanced(by: bounds.lowerBound)
+    let newSpan = unsafe Self(_unchecked: newStart, byteCount: bounds.count)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+  }
+
   /// Constructs a new span over the items within the supplied range of
   /// positions within this span.
   ///
@@ -497,11 +461,28 @@ extension MutableRawSpan {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(
+    _ bounds: some RangeExpression<Int>
+  ) -> Self {
+    _mutatingExtracting(bounds.relative(to: byteOffsets))
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
   mutating public func extracting(
     _ bounds: some RangeExpression<Int>
   ) -> Self {
-    extracting(bounds.relative(to: byteOffsets))
+    _mutatingExtracting(bounds)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(
+    _ bounds: some RangeExpression<Int>
+  ) -> Self {
+    _consumingExtracting(bounds.relative(to: byteOffsets))
   }
 
   /// Constructs a new span over the items within the supplied range of
@@ -521,12 +502,36 @@ extension MutableRawSpan {
   /// - Complexity: O(1)
   @unsafe
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(unchecked bounds: ClosedRange<Int>) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(
+    unchecked bounds: ClosedRange<Int>
+  ) -> Self {
+    let range = unsafe Range(
+      _uncheckedBounds: (bounds.lowerBound, bounds.upperBound + 1)
+    )
+    return unsafe _mutatingExtracting(unchecked: range)
+  }
+
+  @unsafe
+  @available(*, deprecated, renamed: "_mutatingExtracting(unchecked:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(
+    unchecked bounds: ClosedRange<Int>
+  ) -> Self {
+    unsafe _mutatingExtracting(unchecked: bounds)
+  }
+
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(
+    unchecked bounds: ClosedRange<Int>
+  ) -> Self {
     let range = unsafe Range(
-      _uncheckedBounds: (bounds.lowerBound, bounds.upperBound+1)
+      _uncheckedBounds: (bounds.lowerBound, bounds.upperBound + 1)
     )
-    return unsafe extracting(unchecked: range)
+    return unsafe _consumingExtracting(unchecked: range)
   }
 
   /// Constructs a new span over all the items of this span.
@@ -539,15 +544,29 @@ extension MutableRawSpan {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(_: UnboundedRange) -> Self {
-    let newSpan = unsafe Self(_unchecked: _start(), byteCount: _count)
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(_: UnboundedRange) -> Self {
+    let newSpan = unsafe Self(_unchecked: _pointer, byteCount: _count)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
   }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(_: UnboundedRange) -> Self {
+    _mutatingExtracting(...)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(_: UnboundedRange) -> Self {
+    self
+  }
 }
 
 // MARK: prefixes and suffixes
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableRawSpan {
 
   /// Returns a span containing the initial elements of this span,
@@ -566,12 +585,36 @@ extension MutableRawSpan {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(first maxLength: Int) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(first maxLength: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
     _precondition(maxLength >= 0, "Can't have a prefix of negative length")
     let newCount = min(maxLength, byteCount)
     let newSpan = unsafe Self(_unchecked: _pointer, byteCount: newCount)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
+#else
+    fatalError("Unsupported compiler")
+#endif
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(first:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(first maxLength: Int) -> Self {
+    _mutatingExtracting(first: maxLength)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(first maxLength: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
+    _precondition(maxLength >= 0, "Can't have a prefix of negative length")
+    let newCount = min(maxLength, byteCount)
+    let newSpan = unsafe Self(_unchecked: _pointer, byteCount: newCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+#else
+    fatalError("Unsupported compiler")
+#endif
   }
 
   /// Returns a span over all but the given number of trailing elements.
@@ -589,13 +632,38 @@ extension MutableRawSpan {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(droppingLast k: Int) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(droppingLast k: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
     _precondition(k >= 0, "Can't drop a negative number of elements")
     let droppedCount = min(k, byteCount)
     let newCount = byteCount &- droppedCount
     let newSpan = unsafe Self(_unchecked: _pointer, byteCount: newCount)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
+#else
+    fatalError("Unsupported compiler")
+#endif
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(droppingLast:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(droppingLast k: Int) -> Self {
+    _mutatingExtracting(droppingLast: k)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(droppingLast k: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
+    _precondition(k >= 0, "Can't drop a negative number of elements")
+    let droppedCount = min(k, byteCount)
+    let newCount = byteCount &- droppedCount
+    let newSpan = unsafe Self(_unchecked: _pointer, byteCount: newCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+#else
+    fatalError("Unsupported compiler")
+#endif
   }
 
   /// Returns a span containing the final elements of the span,
@@ -614,13 +682,38 @@ extension MutableRawSpan {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(last maxLength: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
+    _precondition(maxLength >= 0, "Can't have a suffix of negative length")
+    let newCount = min(maxLength, byteCount)
+    let newStart = unsafe _pointer?.advanced(by: byteCount &- newCount)
+    let newSpan = unsafe Self(_unchecked: newStart, byteCount: newCount)
+    return unsafe _overrideLifetime(newSpan, mutating: &self)
+#else
+    fatalError("Unsupported compiler")
+#endif
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(last:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
   mutating public func extracting(last maxLength: Int) -> Self {
+    _mutatingExtracting(last: maxLength)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(last maxLength: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
     _precondition(maxLength >= 0, "Can't have a suffix of negative length")
     let newCount = min(maxLength, byteCount)
     let newStart = unsafe _pointer?.advanced(by: byteCount &- newCount)
     let newSpan = unsafe Self(_unchecked: newStart, byteCount: newCount)
     return unsafe _overrideLifetime(newSpan, copying: self)
+#else
+    fatalError("Unsupported compiler")
+#endif
   }
 
   /// Returns a span over all but the given number of initial elements.
@@ -638,13 +731,39 @@ extension MutableRawSpan {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(droppingFirst k: Int) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(droppingFirst k: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
     _precondition(k >= 0, "Can't drop a negative number of bytes")
     let droppedCount = min(k, byteCount)
     let newStart = unsafe _pointer?.advanced(by: droppedCount)
     let newCount = byteCount &- droppedCount
     let newSpan = unsafe Self(_unchecked: newStart, byteCount: newCount)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
+#else
+    fatalError("Unsupported compiler")
+#endif
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(droppingFirst:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(droppingFirst k: Int) -> Self {
+    _mutatingExtracting(droppingFirst: k)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(droppingFirst k: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
+    _precondition(k >= 0, "Can't drop a negative number of bytes")
+    let droppedCount = min(k, byteCount)
+    let newStart = unsafe _pointer?.advanced(by: droppedCount)
+    let newCount = byteCount &- droppedCount
+    let newSpan = unsafe Self(_unchecked: newStart, byteCount: newCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+#else
+    fatalError("Unsupported compiler")
+#endif
   }
 }
diff --git a/stdlib/public/core/Span/MutableSpan.swift b/stdlib/public/core/Span/MutableSpan.swift
index a4de39f18c9e1..3650544fb380c 100644
--- a/stdlib/public/core/Span/MutableSpan.swift
+++ b/stdlib/public/core/Span/MutableSpan.swift
@@ -10,11 +10,16 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if SPAN_COMPATIBILITY_STUB
+import Swift
+#endif
+
 // A MutableSpan<Element> represents a span of memory which
 // contains initialized `Element` instances.
 @safe
 @frozen
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 public struct MutableSpan<Element: ~Copyable>
 : ~Copyable, ~Escapable {
   @usableFromInline
@@ -23,13 +28,21 @@ public struct MutableSpan<Element: ~Copyable>
   @usableFromInline
   internal let _count: Int
 
+  @unsafe
   @_alwaysEmitIntoClient
   internal func _start() -> UnsafeMutableRawPointer {
     unsafe _pointer._unsafelyUnwrappedUnchecked
   }
 
+  @_alwaysEmitIntoClient
+  @inline(__always)
+  @lifetime(immortal)
+  public init() {
+    unsafe _pointer = nil
+    _count = 0
+  }
+
   @unsafe
-  @_unsafeNonescapableResult
   @_alwaysEmitIntoClient
   @lifetime(borrow start)
   internal init(
@@ -41,15 +54,16 @@ public struct MutableSpan<Element: ~Copyable>
   }
 }
 
-@available(SwiftStdlib 6.2, *)
-extension MutableSpan: @unchecked Sendable where Element: Sendable {}
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension MutableSpan: @unchecked Sendable where Element: Sendable & ~Copyable {}
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: ~Copyable {
 
   @unsafe
-  @_unsafeNonescapableResult
-  @usableFromInline
+  @_alwaysEmitIntoClient
   @lifetime(borrow elements)
   internal init(
     _unchecked elements: UnsafeMutableBufferPointer<Element>
@@ -87,7 +101,8 @@ extension MutableSpan where Element: ~Copyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan {
 
   @unsafe
@@ -102,7 +117,8 @@ extension MutableSpan {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: BitwiseCopyable {
 
   @unsafe
@@ -154,7 +170,8 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
@@ -170,7 +187,8 @@ extension Span where Element: ~Copyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
@@ -182,7 +200,8 @@ extension MutableSpan where Element: ~Copyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
 
   @_alwaysEmitIntoClient
@@ -198,7 +217,8 @@ extension RawSpan {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
@@ -211,11 +231,12 @@ extension MutableSpan where Element: ~Copyable {
 }
 
 //MARK: Collection, RandomAccessCollection
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
-  public var count: Int { _count }
+  public var count: Int { _assumeNonNegative(_count) }
 
   @_alwaysEmitIntoClient
   public var isEmpty: Bool { _count == 0 }
@@ -224,11 +245,12 @@ extension MutableSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
   public var indices: Range<Index> {
-    unsafe Range(_uncheckedBounds: (0, _count))
+    unsafe Range(_uncheckedBounds: (0, count))
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: BitwiseCopyable {
 
   /// Construct a RawSpan over the memory represented by this span
@@ -254,10 +276,11 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: ~Copyable {
 
-  /// Accesses the element at the specified position in the `Span`.
+  /// Accesses the element at the specified position in the `MutableSpan`.
   ///
   /// - Parameter position: The offset of the element to access. `position`
   ///     must be greater or equal to zero, and less than `count`.
@@ -276,7 +299,7 @@ extension MutableSpan where Element: ~Copyable {
     }
   }
 
-  /// Accesses the element at the specified position in the `Span`.
+  /// Accesses the element at the specified position in the `MutableSpan`.
   ///
   /// This subscript does not validate `position`; this is an unsafe operation.
   ///
@@ -307,7 +330,8 @@ extension MutableSpan where Element: ~Copyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
@@ -330,56 +354,8 @@ extension MutableSpan where Element: ~Copyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
-extension MutableSpan where Element: BitwiseCopyable {
-
-  /// Accesses the element at the specified position in the `Span`.
-  ///
-  /// - Parameter position: The offset of the element to access. `position`
-  ///     must be greater or equal to zero, and less than `count`.
-  ///
-  /// - Complexity: O(1)
-  @_alwaysEmitIntoClient
-  public subscript(_ position: Index) -> Element {
-    get {
-      _precondition(indices.contains(position), "index out of bounds")
-      return unsafe self[unchecked: position]
-    }
-    @lifetime(self: copy self)
-    set {
-      _precondition(indices.contains(position), "index out of bounds")
-      unsafe self[unchecked: position] = newValue
-    }
-  }
-
-  /// Accesses the element at the specified position in the `Span`.
-  ///
-  /// This subscript does not validate `position`; this is an unsafe operation.
-  ///
-  /// - Parameter position: The offset of the element to access. `position`
-  ///     must be greater or equal to zero, and less than `count`.
-  ///
-  /// - Complexity: O(1)
-  @unsafe
-  @_alwaysEmitIntoClient
-  public subscript(unchecked position: Index) -> Element {
-    get {
-      let offset = position&*MemoryLayout<Element>.stride
-      return unsafe _start().loadUnaligned(
-        fromByteOffset: offset, as: Element.self
-      )
-    }
-    @lifetime(self: copy self)
-    set {
-      let offset = position&*MemoryLayout<Element>.stride
-      unsafe _start().storeBytes(
-        of: newValue, toByteOffset: offset, as: Element.self
-      )
-    }
-  }
-}
-
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: ~Copyable {
 
   //FIXME: mark closure parameter as non-escaping
@@ -410,7 +386,8 @@ extension MutableSpan where Element: ~Copyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: BitwiseCopyable {
 
   //FIXME: mark closure parameter as non-escaping
@@ -428,7 +405,7 @@ extension MutableSpan where Element: BitwiseCopyable {
     _ body: (_ buffer: UnsafeMutableRawBufferPointer) throws(E) -> Result
   ) throws(E) -> Result {
     let bytes = unsafe UnsafeMutableRawBufferPointer(
-      start: (_count == 0) ? nil : _start(),
+      start: (_count == 0) ? nil : _pointer,
       count: _count &* MemoryLayout<Element>.stride
     )
     return try unsafe body(bytes)
@@ -436,231 +413,23 @@ extension MutableSpan where Element: BitwiseCopyable {
 }
 
 //MARK: bulk-update functions
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan {
 
   @_alwaysEmitIntoClient
   @lifetime(self: copy self)
   public mutating func update(repeating repeatedValue: consuming Element) {
+    guard !isEmpty else { return }
     unsafe _start().withMemoryRebound(to: Element.self, capacity: count) {
       unsafe $0.update(repeating: repeatedValue, count: count)
     }
   }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update<S: Sequence>(
-    from source: S
-  ) -> (unwritten: S.Iterator, index: Index) where S.Element == Element {
-    var iterator = source.makeIterator()
-    let index = update(from: &iterator)
-    return (iterator, index)
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    from elements: inout some IteratorProtocol<Element>
-  ) -> Index {
-    var index = 0
-    while index < _count {
-      guard let element = elements.next() else { break }
-      unsafe self[unchecked: index] = element
-      index &+= 1
-    }
-    return index
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    fromContentsOf source: some Collection<Element>
-  ) -> Index {
-    let updated = source.withContiguousStorageIfAvailable {
-      self.update(fromContentsOf: unsafe Span(_unsafeElements: $0))
-    }
-    if let updated {
-      return updated
-    }
-
-    //TODO: use _copyContents here
-
-    var iterator = source.makeIterator()
-    let index = update(from: &iterator)
-    _precondition(
-      iterator.next() == nil,
-      "destination buffer view cannot contain every element from source."
-    )
-    return index
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(fromContentsOf source: Span<Element>) -> Index {
-    guard !source.isEmpty else { return 0 }
-    _precondition(
-      source.count <= self.count,
-      "destination span cannot contain every element from source."
-    )
-    unsafe _start().withMemoryRebound(
-      to: Element.self, capacity: source.count
-    ) { dest in
-      unsafe source.withUnsafeBufferPointer {
-        unsafe dest.update(from: $0.baseAddress!, count: $0.count)
-      }
-    }
-    return source.count
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    fromContentsOf source: borrowing MutableSpan<Element>
-  ) -> Index {
-    update(fromContentsOf: source.span)
-  }
-}
-
-@available(SwiftStdlib 6.2, *)
-extension MutableSpan where Element: ~Copyable {
-
-//  @_alwaysEmitIntoClient
-//  public mutating func moveUpdate(
-//    fromContentsOf source: consuming OutputSpan<Element>
-//  ) -> Index {
-//    guard !source.isEmpty else { return 0 }
-//    _precondition(
-//      source.count <= self.count,
-//      "destination span cannot contain every element from source."
-//    )
-//    let buffer = unsafe source.relinquishBorrowedMemory()
-//    // we must now deinitialize the returned UMBP
-//    unsafe _start().moveInitializeMemory(
-//      as: Element.self, from: buffer.baseAddress!, count: buffer.count
-//    )
-//    return buffer.count
-//  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func moveUpdate(
-    fromContentsOf source: UnsafeMutableBufferPointer<Element>
-  ) -> Index {
-//    let source = OutputSpan(_initializing: source, initialized: source.count)
-//    return self.moveUpdate(fromContentsOf: source)
-    unsafe withUnsafeMutableBufferPointer {
-      unsafe $0.moveUpdate(fromContentsOf: source)
-    }
-  }
-}
-
-@available(SwiftStdlib 6.2, *)
-extension MutableSpan {
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func moveUpdate(
-    fromContentsOf source: Slice<UnsafeMutableBufferPointer<Element>>
-  ) -> Index {
-    unsafe moveUpdate(fromContentsOf: .init(rebasing: source))
-  }
-}
-
-@available(SwiftStdlib 6.2, *)
-extension MutableSpan where Element: BitwiseCopyable {
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    repeating repeatedValue: Element
-  ) where Element: BitwiseCopyable {
-    guard count > 0 else { return }
-    // rebind _start manually in order to avoid assumptions about alignment.
-    let rp = unsafe _start()._rawValue
-    let binding = Builtin.bindMemory(rp, count._builtinWordValue, Element.self)
-    let rebound = unsafe UnsafeMutablePointer<Element>(rp)
-    unsafe rebound.update(repeating: repeatedValue, count: count)
-    Builtin.rebindMemory(rp, binding)
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update<S: Sequence>(
-    from source: S
-  ) -> (unwritten: S.Iterator, index: Index)
-  where S.Element == Element, Element: BitwiseCopyable {
-    var iterator = source.makeIterator()
-    let index = update(from: &iterator)
-    return (iterator, index)
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    from elements: inout some IteratorProtocol<Element>
-  ) -> Index {
-    var index = 0
-    while index < _count {
-      guard let element = elements.next() else { break }
-      unsafe self[unchecked: index] = element
-      index &+= 1
-    }
-    return index
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    fromContentsOf source: some Collection<Element>
-  ) -> Index where Element: BitwiseCopyable {
-    let updated = source.withContiguousStorageIfAvailable {
-      self.update(fromContentsOf: unsafe Span(_unsafeElements: $0))
-    }
-    if let updated {
-      return updated
-    }
-
-    //TODO: use _copyContents here
-
-    var iterator = source.makeIterator()
-    let index = update(from: &iterator)
-    _precondition(
-      iterator.next() == nil,
-      "destination buffer view cannot contain every element from source."
-    )
-    return index
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    fromContentsOf source: Span<Element>
-  ) -> Index where Element: BitwiseCopyable {
-    guard !source.isEmpty else { return 0 }
-    _precondition(
-      source.count <= self.count,
-      "destination span cannot contain every element from source."
-    )
-    unsafe source.withUnsafeBufferPointer {
-      unsafe _start().copyMemory(
-        from: $0.baseAddress!,
-        byteCount: $0.count &* MemoryLayout<Element>.stride
-      )
-    }
-    return source.count
-  }
-
-  @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
-  public mutating func update(
-    fromContentsOf source: borrowing MutableSpan<Element>
-  ) -> Index where Element: BitwiseCopyable {
-    update(fromContentsOf: source.span)
-  }
 }
 
 // MARK: sub-spans
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: ~Copyable {
 
   /// Constructs a new span over the items within the supplied range of
@@ -677,14 +446,32 @@ extension MutableSpan where Element: ~Copyable {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(_ bounds: Range<Index>) -> Self {
+    _precondition(
+      UInt(bitPattern: bounds.lowerBound) <= UInt(bitPattern: _count) &&
+      UInt(bitPattern: bounds.upperBound) <= UInt(bitPattern: _count),
+      "Index range out of bounds"
+    )
+    return unsafe _mutatingExtracting(unchecked: bounds)
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
   mutating public func extracting(_ bounds: Range<Index>) -> Self {
+    _mutatingExtracting(bounds)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(_ bounds: Range<Index>) -> Self {
     _precondition(
       UInt(bitPattern: bounds.lowerBound) <= UInt(bitPattern: _count) &&
       UInt(bitPattern: bounds.upperBound) <= UInt(bitPattern: _count),
       "Index range out of bounds"
     )
-    return unsafe extracting(unchecked: bounds)
+    return unsafe _consumingExtracting(unchecked: bounds)
   }
 
   /// Constructs a new span over the items within the supplied range of
@@ -704,14 +491,32 @@ extension MutableSpan where Element: ~Copyable {
   /// - Complexity: O(1)
   @unsafe
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(unchecked bounds: Range<Index>) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(unchecked bounds: Range<Index>) -> Self {
     let delta = bounds.lowerBound &* MemoryLayout<Element>.stride
     let newStart = unsafe _pointer?.advanced(by: delta)
     let newSpan = unsafe Self(_unchecked: newStart, count: bounds.count)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
   }
 
+  @unsafe
+  @available(*, deprecated, renamed: "_mutatingExtracting(unchecked:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(unchecked bounds: Range<Index>) -> Self {
+    unsafe _mutatingExtracting(unchecked: bounds)
+  }
+
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(unchecked bounds: Range<Index>) -> Self {
+    let delta = bounds.lowerBound &* MemoryLayout<Element>.stride
+    let newStart = unsafe _pointer?.advanced(by: delta)
+    let newSpan = unsafe Self(_unchecked: newStart, count: bounds.count)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+  }
+
   /// Constructs a new span over the items within the supplied range of
   /// positions within this span.
   ///
@@ -726,11 +531,28 @@ extension MutableSpan where Element: ~Copyable {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(
+    _ bounds: some RangeExpression<Index>
+  ) -> Self {
+    _mutatingExtracting(bounds.relative(to: indices))
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
   mutating public func extracting(
     _ bounds: some RangeExpression<Index>
   ) -> Self {
-    extracting(bounds.relative(to: indices))
+    _mutatingExtracting(bounds)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(
+    _ bounds: some RangeExpression<Index>
+  ) -> Self {
+    _consumingExtracting(bounds.relative(to: indices))
   }
 
   /// Constructs a new span over the items within the supplied range of
@@ -750,14 +572,36 @@ extension MutableSpan where Element: ~Copyable {
   /// - Complexity: O(1)
   @unsafe
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(
+    unchecked bounds: ClosedRange<Index>
+  ) -> Self {
+    let range = unsafe Range(
+      _uncheckedBounds: (bounds.lowerBound, bounds.upperBound + 1)
+    )
+    return unsafe _mutatingExtracting(unchecked: range)
+  }
+
+  @unsafe
+  @available(*, deprecated, renamed: "_mutatingExtracting(unchecked:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
   mutating public func extracting(
     unchecked bounds: ClosedRange<Index>
+  ) -> Self {
+    unsafe _mutatingExtracting(unchecked: bounds)
+  }
+
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(
+    unchecked bounds: ClosedRange<Index>
   ) -> Self {
     let range = unsafe Range(
-      _uncheckedBounds: (bounds.lowerBound, bounds.upperBound&+1)
+      _uncheckedBounds: (bounds.lowerBound, bounds.upperBound + 1)
     )
-    return unsafe extracting(unchecked: range)
+    return unsafe _consumingExtracting(unchecked: range)
   }
 
   /// Constructs a new span over all the items of this span.
@@ -770,15 +614,29 @@ extension MutableSpan where Element: ~Copyable {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(_: UnboundedRange) -> Self {
-    let newSpan = unsafe Self(_unchecked: _start(), count: _count)
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(_: UnboundedRange) -> Self {
+    let newSpan = unsafe Self(_unchecked: _pointer, count: _count)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
   }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(_: UnboundedRange) -> Self {
+    _mutatingExtracting(...)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(_: UnboundedRange) -> Self {
+    self
+  }
 }
 
 // MARK: prefixes and suffixes
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension MutableSpan where Element: ~Copyable {
 
   /// Returns a span containing the initial elements of this span,
@@ -797,12 +655,36 @@ extension MutableSpan where Element: ~Copyable {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(first maxLength: Int) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(first maxLength: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
     _precondition(maxLength >= 0, "Can't have a prefix of negative length")
     let newCount = min(maxLength, count)
     let newSpan = unsafe Self(_unchecked: _pointer, count: newCount)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
+#else
+    fatalError("Unsupported compiler")
+#endif
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(first:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(first maxLength: Int) -> Self {
+    _mutatingExtracting(first: maxLength)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(first maxLength: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
+    _precondition(maxLength >= 0, "Can't have a prefix of negative length")
+    let newCount = min(maxLength, count)
+    let newSpan = unsafe Self(_unchecked: _pointer, count: newCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+#else
+    fatalError("Unsupported compiler")
+#endif
   }
 
   /// Returns a span over all but the given number of trailing elements.
@@ -820,13 +702,38 @@ extension MutableSpan where Element: ~Copyable {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(droppingLast k: Int) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(droppingLast k: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
     _precondition(k >= 0, "Can't drop a negative number of elements")
     let droppedCount = min(k, count)
     let newCount = count &- droppedCount
     let newSpan = unsafe Self(_unchecked: _pointer, count: newCount)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
+#else
+    fatalError("Unsupported compiler")
+#endif
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(droppingLast:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(droppingLast k: Int) -> Self {
+    _mutatingExtracting(droppingLast: k)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(droppingLast k: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
+    _precondition(k >= 0, "Can't drop a negative number of elements")
+    let droppedCount = min(k, count)
+    let newCount = count &- droppedCount
+    let newSpan = unsafe Self(_unchecked: _pointer, count: newCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+#else
+    fatalError("Unsupported compiler")
+#endif
   }
 
   /// Returns a span containing the final elements of the span,
@@ -845,14 +752,40 @@ extension MutableSpan where Element: ~Copyable {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(last maxLength: Int) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(last maxLength: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
     _precondition(maxLength >= 0, "Can't have a suffix of negative length")
     let newCount = min(maxLength, count)
     let offset = (count &- newCount) * MemoryLayout<Element>.stride
     let newStart = unsafe _pointer?.advanced(by: offset)
     let newSpan = unsafe Self(_unchecked: newStart, count: newCount)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
+#else
+    fatalError("Unsupported compiler")
+#endif
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(last:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(last maxLength: Int) -> Self {
+    _mutatingExtracting(last: maxLength)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(last maxLength: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
+    _precondition(maxLength >= 0, "Can't have a suffix of negative length")
+    let newCount = min(maxLength, count)
+    let offset = (count &- newCount) * MemoryLayout<Element>.stride
+    let newStart = unsafe _pointer?.advanced(by: offset)
+    let newSpan = unsafe Self(_unchecked: newStart, count: newCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+#else
+    fatalError("Unsupported compiler")
+#endif
   }
 
   /// Returns a span over all but the given number of initial elements.
@@ -870,8 +803,9 @@ extension MutableSpan where Element: ~Copyable {
   ///
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
-  @lifetime(borrow self)
-  mutating public func extracting(droppingFirst k: Int) -> Self {
+  @lifetime(&self)
+  mutating public func _mutatingExtracting(droppingFirst k: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
     _precondition(k >= 0, "Can't drop a negative number of elements")
     let droppedCount = min(k, count)
     let offset = droppedCount * MemoryLayout<Element>.stride
@@ -879,5 +813,31 @@ extension MutableSpan where Element: ~Copyable {
     let newCount = count &- droppedCount
     let newSpan = unsafe Self(_unchecked: newStart, count: newCount)
     return unsafe _overrideLifetime(newSpan, mutating: &self)
+#else
+    fatalError("Unsupported compiler")
+#endif
+  }
+
+  @available(*, deprecated, renamed: "_mutatingExtracting(droppingFirst:)")
+  @_alwaysEmitIntoClient
+  @lifetime(&self)
+  mutating public func extracting(droppingFirst k: Int) -> Self {
+    _mutatingExtracting(droppingFirst: k)
+  }
+
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  consuming public func _consumingExtracting(droppingFirst k: Int) -> Self {
+#if compiler(>=5.3) && hasFeature(SendableCompletionHandlers)
+    _precondition(k >= 0, "Can't drop a negative number of elements")
+    let droppedCount = min(k, count)
+    let offset = droppedCount * MemoryLayout<Element>.stride
+    let newStart = unsafe _pointer?.advanced(by: offset)
+    let newCount = count &- droppedCount
+    let newSpan = unsafe Self(_unchecked: newStart, count: newCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+#else
+    fatalError("Unsupported compiler")
+#endif
   }
 }
diff --git a/stdlib/public/core/Span/OutputRawSpan.swift b/stdlib/public/core/Span/OutputRawSpan.swift
new file mode 100644
index 0000000000000..e2e8a54f815dc
--- /dev/null
+++ b/stdlib/public/core/Span/OutputRawSpan.swift
@@ -0,0 +1,380 @@
+//===--- OutputRawSpan.swift ----------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#if SPAN_COMPATIBILITY_STUB
+import Swift
+#endif
+
+// OutputRawSpan is a reference to a contiguous region of memory which starts
+// some number of initialized bytes, followed by uninitialized memory.
+@safe
+@frozen
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+public struct OutputRawSpan: ~Copyable, ~Escapable {
+  @usableFromInline
+  internal let _pointer: UnsafeMutableRawPointer?
+
+  public let capacity: Int
+
+  @usableFromInline
+  internal var _count: Int
+
+  /// Create an OutputRawSpan with zero capacity
+  @_alwaysEmitIntoClient
+  @lifetime(immortal)
+  public init() {
+    unsafe _pointer = nil
+    capacity = 0
+    _count = 0
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputRawSpan: @unchecked Sendable {}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputRawSpan {
+  @_alwaysEmitIntoClient
+  @_transparent
+  @unsafe
+  internal func _start() -> UnsafeMutableRawPointer {
+    unsafe _pointer._unsafelyUnwrappedUnchecked
+  }
+
+  @_alwaysEmitIntoClient
+  @_transparent
+  @unsafe
+  internal func _tail() -> UnsafeMutableRawPointer {
+    // NOTE: `_pointer` must be known to be not-nil.
+    unsafe _start().advanced(by: _count)
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputRawSpan {
+  /// The number of initialized bytes in this span.
+  @_alwaysEmitIntoClient
+  public var byteCount: Int { _count }
+
+  /// The number of additional bytes that can be appended to this span.
+  @_alwaysEmitIntoClient
+  public var freeCapacity: Int { capacity &- _count }
+
+  /// A Boolean value indicating whether the span is empty.
+  @_alwaysEmitIntoClient
+  public var isEmpty: Bool { _count == 0 }
+
+  /// A Boolean value indicating whether the span is full.
+  @_alwaysEmitIntoClient
+  public var isFull: Bool { _count == capacity }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputRawSpan {
+
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(borrow buffer)
+  internal init(
+    _uncheckedBuffer buffer: UnsafeMutableRawBufferPointer,
+    initializedCount: Int
+  ) {
+    unsafe _pointer = .init(buffer.baseAddress)
+    capacity = buffer.count
+    _count = initializedCount
+  }
+
+  /// Unsafely create an OutputRawSpan over partly-initialized memory.
+  ///
+  /// The memory in `buffer` must remain valid throughout the lifetime
+  /// of the newly-created `OutputRawSpan`. Its prefix must contain
+  /// `initializedCount` initialized bytes, followed by uninitialized
+  /// memory.
+  ///
+  /// - Parameters:
+  ///   - buffer: an `UnsafeMutableBufferPointer` to be initialized
+  ///   - initializedCount: the number of initialized bytes
+  ///                       at the beginning of `buffer`.
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(borrow buffer)
+  public init(
+    buffer: UnsafeMutableRawBufferPointer,
+    initializedCount: Int
+  ) {
+    if let baseAddress = buffer.baseAddress {
+      _precondition(
+        unsafe baseAddress.advanced(by: buffer.count) >= baseAddress,
+        "Buffer must not wrap around the address space"
+      )
+    }
+    _precondition(
+      0 <= initializedCount && initializedCount <= buffer.count,
+      "OutputSpan count is not within capacity"
+    )
+    unsafe self.init(
+      _uncheckedBuffer: buffer, initializedCount: initializedCount
+    )
+  }
+
+  /// Unsafely create an OutputRawSpan over partly-initialized memory.
+  ///
+  /// The memory in `buffer` must remain valid throughout the lifetime
+  /// of the newly-created `OutputRawSpan`. Its prefix must contain
+  /// `initializedCount` initialized bytes, followed by uninitialized
+  /// memory.
+  ///
+  /// - Parameters:
+  ///   - buffer: an `UnsafeMutableBufferPointer` to be initialized
+  ///   - initializedCount: the number of initialized bytes
+  ///                       at the beginning of `buffer`.
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(borrow buffer)
+  public init(
+    buffer: borrowing Slice<UnsafeMutableRawBufferPointer>,
+    initializedCount: Int
+  ) {
+    let rebased = unsafe UnsafeMutableRawBufferPointer(rebasing: buffer)
+    let os = unsafe OutputRawSpan(
+      buffer: rebased, initializedCount: initializedCount
+    )
+    self = unsafe _overrideLifetime(os, borrowing: buffer)
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputRawSpan {
+
+  /// Append a single byte to this span.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func append(_ value: UInt8) {
+    _precondition(_count < capacity, "OutputRawSpan capacity overflow")
+    unsafe _tail().storeBytes(of: value, as: UInt8.self)
+    _count &+= 1
+  }
+
+  /// Remove the last byte from this span.
+  @_alwaysEmitIntoClient
+  @discardableResult
+  @lifetime(self: copy self)
+  public mutating func removeLast() -> UInt8 {
+    _precondition(!isEmpty, "OutputRawSpan underflow")
+    _count &-= 1
+    return unsafe _tail().load(as: UInt8.self)
+  }
+
+  /// Remove the last N elements, returning the memory they occupy
+  /// to the uninitialized state.
+  ///
+  /// `n` must not be greater than `count`
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func removeLast(_ k: Int) {
+    _precondition(k >= 0, "Can't remove a negative number of bytes")
+    _precondition(k <= _count, "OutputRawSpan underflow")
+    _count &-= k
+  }
+
+  /// Remove all this span's elements and return its memory
+  /// to the uninitialized state.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func removeAll() {
+    // TODO: Consider an option to zero the `_count` bytes being removed.
+    _count = 0
+  }
+}
+
+//MARK: bulk-append functions
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputRawSpan {
+  /// Appends the given value's bytes to this span's bytes.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func append<T: BitwiseCopyable>(_ value: T, as type: T.Type) {
+    _precondition(
+      MemoryLayout<T>.size <= freeCapacity, "OutputRawSpan capacity overflow"
+    )
+    unsafe _tail().initializeMemory(as: T.self, to: value)
+    _count &+= MemoryLayout<T>.size
+  }
+
+  /// Appends the given value's bytes repeatedly to this span's bytes.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func append<T: BitwiseCopyable>(
+    repeating repeatedValue: T, count: Int, as type: T.Type
+  ) {
+    let total = count * MemoryLayout<T>.stride
+    _precondition(total <= freeCapacity, "OutputRawSpan capacity overflow")
+    unsafe _tail().initializeMemory(
+      as: T.self, repeating: repeatedValue, count: count
+    )
+    _count &+= total
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputRawSpan {
+  /// Borrow the underlying initialized memory for read-only access.
+  @_alwaysEmitIntoClient
+  public var bytes: RawSpan {
+    @lifetime(borrow self)
+    borrowing get {
+      let buffer = unsafe UnsafeRawBufferPointer(start: _pointer, count: _count)
+      let span = unsafe RawSpan(_unsafeBytes: buffer)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+  }
+
+  /// Exclusively borrow the underlying initialized memory for mutation.
+  @_alwaysEmitIntoClient
+  public var mutableBytes: MutableRawSpan {
+    @lifetime(&self)
+    mutating get {
+      let buffer = unsafe UnsafeMutableRawBufferPointer(
+        start: _pointer, count: _count
+      )
+      let span = unsafe MutableRawSpan(_unsafeBytes: buffer)
+      return unsafe _overrideLifetime(span, mutating: &self)
+    }
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputRawSpan {
+
+  /// Call the given closure with the unsafe buffer pointer addressed by this
+  /// OutputRawSpan and a mutable reference to its count of initialized bytes.
+  ///
+  /// This method provides a way to process or populate an `OutputRawSpan` using
+  /// unsafe operations, such as dispatching to code written in legacy
+  /// (memory-unsafe) languages.
+  ///
+  /// The supplied closure may process the buffer in any way it wants; however,
+  /// when it finishes (whether by returning or throwing), it must leave the
+  /// buffer in a state that satisfies the invariants of the output span:
+  ///
+  /// 1. The inout integer passed in as the second argument must be the exact
+  ///     number of initialized bytes in the buffer passed in as the first
+  ///     argument.
+  /// 2. These initialized elements must be located in a single contiguous
+  ///     region starting at the beginning of the buffer. The rest of the buffer
+  ///     must hold uninitialized memory.
+  ///
+  /// This function cannot verify these two invariants, and therefore
+  /// this is an unsafe operation. Violating the invariants of `OutputRawSpan`
+  /// may result in undefined behavior.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func withUnsafeMutableBytes<E: Error, R: ~Copyable>(
+    _ body: (
+      UnsafeMutableRawBufferPointer,
+      _ initializedCount: inout Int
+    ) throws(E) -> R
+  ) throws(E) -> R {
+    guard let start = unsafe _pointer, capacity > 0 else {
+      let buffer = UnsafeMutableRawBufferPointer(_empty: ())
+      var initializedCount = 0
+      defer {
+        _precondition(initializedCount == 0, "OutputRawSpan capacity overflow")
+      }
+      return unsafe try body(buffer, &initializedCount)
+    }
+#if SPAN_COMPATIBILITY_STUB
+    let buffer = unsafe UnsafeMutableRawBufferPointer(
+      start: start, count: capacity
+    )
+#else
+    let buffer = unsafe UnsafeMutableRawBufferPointer(
+      _uncheckedStart: start, count: capacity
+    )
+#endif
+    var initializedCount = _count
+    defer {
+      _precondition(
+        0 <= initializedCount && initializedCount <= capacity,
+        "OutputRawSpan capacity overflow"
+      )
+      _count = initializedCount
+    }
+    return unsafe try body(buffer, &initializedCount)
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputRawSpan {
+  /// Consume the output span (relinquishing its control over the buffer it is
+  /// addressing), and return the number of initialized bytes in it.
+  ///
+  /// This method should be invoked in the scope where the `OutputRawSpan` was
+  /// created, when it is time to commit the contents of the updated buffer
+  /// back into the construct being initialized.
+  ///
+  /// The context that created the output span is expected to remember what
+  /// memory region the span is addressing. This consuming method expects to
+  /// receive a copy of the same buffer pointer as a (loose) proof of ownership.
+  ///
+  /// - Parameter buffer: The buffer we expect the `OutputRawSpan` to reference.
+  ///      This must be the same region of memory passed to
+  ///      the `OutputRawSpan` initializer.
+  /// - Returns: The number of initialized bytes in the same buffer, as
+  ///      tracked by the consumed `OutputRawSpan` instance.
+  @unsafe
+  @_alwaysEmitIntoClient
+  public consuming func finalize(
+    for buffer: UnsafeMutableRawBufferPointer
+  ) -> Int {
+    _precondition(
+      unsafe buffer.baseAddress == self._pointer
+      && buffer.count == self.capacity,
+      "OutputRawSpan identity mismatch")
+    return _count
+  }
+
+  /// Consume the output span (relinquishing its control over the buffer it is
+  /// addressing), and return the number of initialized bytes in it.
+  ///
+  /// This method should be invoked in the scope where the `OutputRawSpan` was
+  /// created, when it is time to commit the contents of the updated buffer
+  /// back into the construct being initialized.
+  ///
+  /// The context that created the output span is expected to remember what
+  /// memory region the span is addressing. This consuming method expects to
+  /// receive a copy of the same buffer pointer as a (loose) proof of ownership.
+  ///
+  /// - Parameter buffer: The buffer we expect the `OutputRawSpan` to reference.
+  ///      This must be the same region of memory passed to
+  ///      the `OutputRawSpan` initializer.
+  /// - Returns: The number of initialized bytes in the same buffer, as
+  ///      tracked by the consumed `OutputRawSpan` instance.
+  @unsafe
+  @_alwaysEmitIntoClient
+  public consuming func finalize(
+    for buffer: Slice<UnsafeMutableRawBufferPointer>
+  ) -> Int {
+    let rebased = unsafe UnsafeMutableRawBufferPointer(rebasing: buffer)
+    return unsafe self.finalize(for: rebased)
+  }
+}
diff --git a/stdlib/public/core/Span/OutputSpan.swift b/stdlib/public/core/Span/OutputSpan.swift
new file mode 100644
index 0000000000000..41ae4d7f7bef4
--- /dev/null
+++ b/stdlib/public/core/Span/OutputSpan.swift
@@ -0,0 +1,498 @@
+//===--- OutputSpan.swift -------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#if SPAN_COMPATIBILITY_STUB
+import Swift
+#endif
+
+// `OutputSpan` is a reference to a contiguous region of memory that starts with
+// some number of initialized `Element` instances followed by uninitialized
+// memory. It provides operations to access the items it stores, as well as to
+// add new elements and to remove existing ones.
+@safe
+@frozen
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+public struct OutputSpan<Element: ~Copyable>: ~Copyable, ~Escapable {
+  @usableFromInline
+  internal let _pointer: UnsafeMutableRawPointer?
+
+  public let capacity: Int
+
+  @usableFromInline
+  internal var _count: Int
+
+  @_alwaysEmitIntoClient
+  @inlinable
+  deinit {
+    if _count > 0 {
+      unsafe _start().withMemoryRebound(
+        to: Element.self, capacity: _count
+      ) {
+        [ workaround = _count ] in
+        _ = unsafe $0.deinitialize(count: workaround)
+      }
+    }
+  }
+
+  /// Create an OutputSpan with zero capacity
+  @_alwaysEmitIntoClient
+  @lifetime(immortal)
+  public init() {
+    unsafe _pointer = nil
+    capacity = 0
+    _count = 0
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan: @unchecked Sendable where Element: Sendable & ~Copyable {}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan where Element: ~Copyable {
+  @_alwaysEmitIntoClient
+  @_transparent
+  @unsafe
+  internal func _start() -> UnsafeMutableRawPointer {
+    unsafe _pointer._unsafelyUnwrappedUnchecked
+  }
+
+  @_alwaysEmitIntoClient
+  @_transparent
+  @unsafe
+  internal func _tail() -> UnsafeMutableRawPointer {
+    // NOTE: `_pointer` must be known to be not-nil.
+    unsafe _start().advanced(by: _count &* MemoryLayout<Element>.stride)
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan where Element: ~Copyable {
+  /// The number of initialized elements in this span.
+  @_alwaysEmitIntoClient
+  public var count: Int { _count }
+
+  /// The number of additional elements that can be added to this span.
+  @_alwaysEmitIntoClient
+  public var freeCapacity: Int { capacity &- _count }
+
+  /// A Boolean value indicating whether the span is empty.
+  @_alwaysEmitIntoClient
+  public var isEmpty: Bool { _count == 0 }
+
+  /// A Boolean value indicating whether the span is full.
+  @_alwaysEmitIntoClient
+  public var isFull: Bool { _count == capacity }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan where Element: ~Copyable  {
+
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(borrow buffer)
+  @usableFromInline
+  internal init(
+    _uncheckedBuffer buffer: UnsafeMutableBufferPointer<Element>,
+    initializedCount: Int
+  ) {
+    unsafe _pointer = .init(buffer.baseAddress)
+    capacity = buffer.count
+    _count = initializedCount
+  }
+
+  /// Unsafely create an OutputSpan over partly-initialized memory.
+  ///
+  /// The memory in `buffer` must remain valid throughout the lifetime
+  /// of the newly-created `OutputSpan`. Its prefix must contain
+  /// `initializedCount` initialized instances, followed by uninitialized
+  /// memory. The default value of `initializedCount` is 0, representing
+  /// the common case of a completely uninitialized `buffer`.
+  ///
+  /// - Parameters:
+  ///   - buffer: an `UnsafeMutableBufferPointer` to be initialized
+  ///   - initializedCount: the number of initialized elements
+  ///                       at the beginning of `buffer`.
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(borrow buffer)
+  public init(
+    buffer: UnsafeMutableBufferPointer<Element>,
+    initializedCount: Int
+  ) {
+    _precondition(buffer._isWellAligned(), "Misaligned OutputSpan")
+    if let baseAddress = buffer.baseAddress {
+      _precondition(
+        unsafe baseAddress.advanced(by: buffer.count) >= baseAddress,
+        "Buffer must not wrap around the address space"
+      )
+    }
+    _precondition(
+      0 <= initializedCount && initializedCount <= buffer.count,
+      "OutputSpan count is not within capacity"
+    )
+    unsafe self.init(
+      _uncheckedBuffer: buffer, initializedCount: initializedCount
+    )
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan {
+
+  /// Unsafely create an OutputSpan over partly-initialized memory.
+  ///
+  /// The memory in `buffer` must remain valid throughout the lifetime
+  /// of the newly-created `OutputSpan`. Its prefix must contain
+  /// `initializedCount` initialized instances, followed by uninitialized
+  /// memory. The default value of `initializedCount` is 0, representing
+  /// the common case of a completely uninitialized `buffer`.
+  ///
+  /// - Parameters:
+  ///   - buffer: an `UnsafeMutableBufferPointer` to be initialized
+  ///   - initializedCount: the number of initialized elements
+  ///                       at the beginning of `buffer`.
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(borrow buffer)
+  public init(
+    buffer: borrowing Slice<UnsafeMutableBufferPointer<Element>>,
+    initializedCount: Int
+  ) {
+    let rebased = unsafe UnsafeMutableBufferPointer(rebasing: buffer)
+    let os = unsafe OutputSpan(
+      buffer: rebased, initializedCount: initializedCount
+    )
+    self = unsafe _overrideLifetime(os, borrowing: buffer)
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan where Element: ~Copyable {
+  /// The type that represents an initialized position in an `OutputSpan`.
+  public typealias Index = Int
+
+  /// The range of initialized positions for this `OutputSpan`.
+  @_alwaysEmitIntoClient
+  public var indices: Range<Index> {
+    unsafe Range(_uncheckedBounds: (0, _count))
+  }
+
+  /// Accesses the element at the specified position.
+  ///
+  /// - Parameter index: A valid index into this span.
+  ///
+  /// - Complexity: O(1)
+  @_alwaysEmitIntoClient
+  public subscript(_ index: Index) -> Element {
+    unsafeAddress {
+      _precondition(indices.contains(index), "index out of bounds")
+      return unsafe UnsafePointer(_unsafeAddressOfElement(unchecked: index))
+    }
+    @lifetime(self: copy self)
+    unsafeMutableAddress {
+      _precondition(indices.contains(index), "index out of bounds")
+      return unsafe _unsafeAddressOfElement(unchecked: index)
+    }
+  }
+
+  /// Accesses the element at the specified position.
+  ///
+  /// This subscript does not validate `position`; this is an unsafe operation.
+  ///
+  /// - Parameter index: A valid index into this span.
+  ///
+  /// - Complexity: O(1)
+  @unsafe
+  @_alwaysEmitIntoClient
+  public subscript(unchecked index: Index) -> Element {
+    unsafeAddress {
+      unsafe UnsafePointer(_unsafeAddressOfElement(unchecked: index))
+    }
+    @lifetime(self: copy self)
+    unsafeMutableAddress {
+      unsafe _unsafeAddressOfElement(unchecked: index)
+    }
+  }
+
+  @unsafe
+  @_alwaysEmitIntoClient
+  internal func _unsafeAddressOfElement(
+    unchecked index: Index
+  ) -> UnsafeMutablePointer<Element> {
+    let elementOffset = index &* MemoryLayout<Element>.stride
+    let address = unsafe _start().advanced(by: elementOffset)
+    return unsafe address.assumingMemoryBound(to: Element.self)
+  }
+
+  /// Exchange the elements at the two given offsets
+  ///
+  /// - Parameter i: A valid index into this span.
+  /// - Parameter j: A valid index into this span.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func swapAt(_ i: Index, _ j: Index) {
+    _precondition(indices.contains(Index(i)))
+    _precondition(indices.contains(Index(j)))
+    unsafe swapAt(unchecked: i, unchecked: j)
+  }
+
+  /// Exchange the elements at the two given offsets
+  ///
+  /// This subscript does not validate `i` or `j`; this is an unsafe operation.
+  ///
+  /// - Parameter i: A valid index into this span.
+  /// - Parameter j: A valid index into this span.
+  @unsafe
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func swapAt(unchecked i: Index, unchecked j: Index) {
+    let pi = unsafe _unsafeAddressOfElement(unchecked: i)
+    let pj = unsafe _unsafeAddressOfElement(unchecked: j)
+    let temporary = unsafe pi.move()
+    unsafe pi.initialize(to: pj.move())
+    unsafe pj.initialize(to: consume temporary)
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan where Element: ~Copyable {
+  /// Append a single element to this span.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func append(_ value: consuming Element) {
+    _precondition(_count < capacity, "OutputSpan capacity overflow")
+    unsafe _tail().initializeMemory(as: Element.self, to: value)
+    _count &+= 1
+  }
+
+  /// Remove the last initialized element from this span.
+  ///
+  /// Returns the last element. The `OutputSpan` must not be empty.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func removeLast() -> Element {
+    _precondition(!isEmpty, "OutputSpan underflow")
+    _count &-= 1
+    return unsafe _tail().withMemoryRebound(to: Element.self, capacity: 1) {
+      unsafe $0.move()
+    }
+  }
+
+  /// Remove the last N elements of this span, returning the memory they occupy
+  /// to the uninitialized state.
+  ///
+  /// `n` must not be greater than `count`
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func removeLast(_ k: Int) {
+    _precondition(k >= 0, "Can't remove a negative number of elements")
+    _precondition(k <= _count, "OutputSpan underflow")
+    _count &-= k
+    unsafe _tail().withMemoryRebound(to: Element.self, capacity: k) {
+      _ = unsafe $0.deinitialize(count: k)
+    }
+  }
+
+  /// Remove all this span's elements and return its memory
+  /// to the uninitialized state.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func removeAll() {
+    guard count > 0 else { return }
+    _ = unsafe _start().withMemoryRebound(to: Element.self, capacity: _count) {
+      unsafe $0.deinitialize(count: _count)
+    }
+    _count = 0
+  }
+}
+
+//MARK: bulk-append functions
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan {
+
+  /// Repeatedly append an element to this span.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func append(repeating repeatedValue: Element, count: Int) {
+    _precondition(count <= freeCapacity, "OutputSpan capacity overflow")
+    unsafe _tail().initializeMemory(
+      as: Element.self, repeating: repeatedValue, count: count
+    )
+    _count &+= count
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan where Element: ~Copyable {
+  /// Borrow the underlying initialized memory for read-only access.
+  @_alwaysEmitIntoClient
+  public var span: Span<Element> {
+    @lifetime(borrow self)
+    borrowing get {
+      let pointer = unsafe _pointer?.assumingMemoryBound(to: Element.self)
+      let buffer = unsafe UnsafeBufferPointer(start: pointer, count: _count)
+      let span = unsafe Span(_unsafeElements: buffer)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+  }
+
+  /// Exclusively borrow the underlying initialized memory for mutation.
+  @_alwaysEmitIntoClient
+  public var mutableSpan: MutableSpan<Element> {
+    @lifetime(&self)
+    mutating get {
+      let pointer = unsafe _pointer?.assumingMemoryBound(to: Element.self)
+      let buffer = unsafe UnsafeMutableBufferPointer(
+        start: pointer, count: _count
+      )
+      let span = unsafe MutableSpan(_unsafeElements: buffer)
+      return unsafe _overrideLifetime(span, mutating: &self)
+    }
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan where Element: ~Copyable {
+  /// Call the given closure with the unsafe buffer pointer addressed by this
+  /// OutputSpan and a mutable reference to its count of initialized elements.
+  ///
+  /// This method provides a way to process or populate an `OutputSpan` using
+  /// unsafe operations, such as dispatching to code written in legacy
+  /// (memory-unsafe) languages.
+  ///
+  /// The supplied closure may process the buffer in any way it wants; however,
+  /// when it finishes (whether by returning or throwing), it must leave the
+  /// buffer in a state that satisfies the invariants of the output span:
+  ///
+  /// 1. The inout integer passed in as the second argument must be the exact
+  ///     number of initialized items in the buffer passed in as the first
+  ///     argument.
+  /// 2. These initialized elements must be located in a single contiguous
+  ///     region starting at the beginning of the buffer. The rest of the buffer
+  ///     must hold uninitialized memory.
+  ///
+  /// This function cannot verify these two invariants, and therefore
+  /// this is an unsafe operation. Violating the invariants of `OutputSpan`
+  /// may result in undefined behavior.
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  public mutating func withUnsafeMutableBufferPointer<E: Error, R: ~Copyable>(
+    _ body: (
+      UnsafeMutableBufferPointer<Element>,
+      _ initializedCount: inout Int
+    ) throws(E) -> R
+  ) throws(E) -> R {
+    guard let start = unsafe _pointer, capacity > 0 else {
+      let buffer = UnsafeMutableBufferPointer<Element>(_empty: ())
+      var initializedCount = 0
+      defer {
+        _precondition(initializedCount == 0, "OutputSpan capacity overflow")
+      }
+      return unsafe try body(buffer, &initializedCount)
+    }
+    // bind memory by hand to sidestep alignment concerns
+    let binding = Builtin.bindMemory(
+      start._rawValue, capacity._builtinWordValue, Element.self
+    )
+    defer { Builtin.rebindMemory(start._rawValue, binding) }
+#if SPAN_COMPATIBILITY_STUB
+    let buffer = unsafe UnsafeMutableBufferPointer<Element>(
+      start: .init(start._rawValue), count: capacity
+    )
+#else
+    let buffer = unsafe UnsafeMutableBufferPointer<Element>(
+      _uncheckedStart: .init(start._rawValue), count: capacity
+    )
+#endif
+    var initializedCount = self._count
+    defer {
+      _precondition(
+        0 <= initializedCount && initializedCount <= capacity,
+        "OutputSpan capacity overflow"
+      )
+      self._count = initializedCount
+    }
+    return unsafe try body(buffer, &initializedCount)
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan where Element: ~Copyable {
+  /// Consume the output span and return the number of initialized elements.
+  ///
+  /// This method should be invoked in the scope where the `OutputSpan` was
+  /// created, when it is time to commit the contents of the updated buffer
+  /// back into the construct being initialized.
+  ///
+  /// The context that created the output span is expected to remember what
+  /// memory region the span is addressing. This consuming method expects to
+  /// receive a copy of the same buffer pointer as a (loose) proof of ownership.
+  ///
+  /// - Parameter buffer: The buffer we expect the `OutputSpan` to reference.
+  ///      This must be the same region of memory passed to
+  ///      the `OutputSpan` initializer.
+  /// - Returns: The number of initialized elements in the same buffer, as
+  ///      tracked by the consumed `OutputSpan` instance.
+  @unsafe
+  @_alwaysEmitIntoClient
+  public consuming func finalize(
+    for buffer: UnsafeMutableBufferPointer<Element>
+  ) -> Int {
+    _precondition(
+      unsafe UnsafeMutableRawPointer(buffer.baseAddress) == self._pointer
+      && buffer.count == self.capacity,
+      "OutputSpan identity mismatch"
+    )
+    let count = self._count
+    discard self
+    return count
+  }
+}
+
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension OutputSpan {
+  /// Consume the output span and return the number of initialized elements.
+  ///
+  /// This method should be invoked in the scope where the `OutputSpan` was
+  /// created, when it is time to commit the contents of the updated buffer
+  /// back into the construct being initialized.
+  ///
+  /// The context that created the output span is expected to remember what
+  /// memory region the span is addressing. This consuming method expects to
+  /// receive a copy of the same buffer pointer as a (loose) proof of ownership.
+  ///
+  /// - Parameter buffer: The buffer we expect the `OutputSpan` to reference.
+  ///      This must be the same region of memory passed to
+  ///      the `OutputSpan` initializer.
+  /// - Returns: The number of initialized elements in the same buffer, as
+  ///      tracked by the consumed `OutputSpan` instance.
+  @unsafe
+  @_alwaysEmitIntoClient
+  public consuming func finalize(
+    for buffer: Slice<UnsafeMutableBufferPointer<Element>>
+  ) -> Int {
+    unsafe finalize(for: UnsafeMutableBufferPointer(rebasing: buffer))
+  }
+}
diff --git a/stdlib/public/core/Span/RawSpan.swift b/stdlib/public/core/Span/RawSpan.swift
index e1f6238222b97..eef47aeb2c18d 100644
--- a/stdlib/public/core/Span/RawSpan.swift
+++ b/stdlib/public/core/Span/RawSpan.swift
@@ -21,18 +21,19 @@ import Swift
 /// When a `RawSpan` is created, it inherits the lifetime of the container
 /// owning the contiguous memory, ensuring temporal safety and avoiding
 /// use-after-free errors. Operations on `RawSpan` are bounds-checked,
-/// ensuring spcial safety and avoiding buffer overflow errors.
-@available(SwiftStdlib 6.2, *)
+/// ensuring spatial safety and avoiding buffer overflow errors.
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 @frozen
 @safe
 public struct RawSpan: ~Escapable, Copyable, BitwiseCopyable {
 
   /// The starting address of this `RawSpan`.
   ///
-  /// `_pointer` can be `nil` if and only if `_count` equals 0.
-  /// Otherwise, `_pointer` must point to memory that will remain
-  /// valid and not mutated as long as this `Span` exists.
-  /// The memory at `_pointer` must consist of `_count` initialized bytes.
+  /// If `_count` is zero, `_pointer` may point to valid memory or it may be `nil`,
+  /// but no accesses may be performed through it. Otherwise, `_pointer` must point
+  /// to initialized memory containing `_count` bytes, which must remain valid and
+  /// not be mutated during the lifetime of this `RawSpan`.
   @usableFromInline
   internal let _pointer: UnsafeRawPointer?
 
@@ -53,7 +54,7 @@ public struct RawSpan: ~Escapable, Copyable, BitwiseCopyable {
   @_alwaysEmitIntoClient
   @inline(__always)
   @lifetime(immortal)
-  internal init() {
+  public init() {
     unsafe _pointer = nil
     _count = 0
   }
@@ -84,10 +85,12 @@ public struct RawSpan: ~Escapable, Copyable, BitwiseCopyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan: @unchecked Sendable {}
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
 
   /// Unsafely create a `RawSpan` over initialized memory.
@@ -285,14 +288,14 @@ extension RawSpan {
 
   /// Unsafely create a `RawSpan` over initialized memory.
   ///
-  /// The region of memory representing `byteCount` bytes starting at `pointer`
+  /// The region of memory representing `count` elements starting at `pointer`
   /// must remain valid, initialized and immutable
   /// throughout the lifetime of the newly-created `RawSpan`.
   /// Failure to maintain this invariant results in undefined behaviour.
   ///
   /// - Parameters:
   ///   - pointer: a pointer to the first initialized byte.
-  ///   - byteCount: the number of initialized bytes in the span.
+  ///   - count: the number of initialized elements in the span.
   @unsafe
   @_alwaysEmitIntoClient
   @lifetime(borrow pointer)
@@ -326,7 +329,8 @@ extension RawSpan {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
 
   /// The number of bytes in the span.
@@ -355,7 +359,8 @@ extension RawSpan {
 }
 
 // MARK: extracting sub-spans
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
 
   /// Constructs a new span over the bytes within the supplied range of
@@ -373,13 +378,20 @@ extension RawSpan {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(_ bounds: Range<Int>) -> Self {
+  public func extracting(_ bounds: Range<Int>) -> Self {
     _precondition(
       UInt(bitPattern: bounds.lowerBound) <= UInt(bitPattern: _count) &&
       UInt(bitPattern: bounds.upperBound) <= UInt(bitPattern: _count),
       "Byte offset range out of bounds"
     )
-    return unsafe _extracting(unchecked: bounds)
+    return unsafe extracting(unchecked: bounds)
+  }
+
+  @available(*, deprecated, renamed: "extracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(_ bounds: Range<Int>) -> Self {
+    extracting(bounds)
   }
 
   /// Constructs a new span over the bytes within the supplied range of
@@ -400,12 +412,20 @@ extension RawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(unchecked bounds: Range<Int>) -> Self {
+  public func extracting(unchecked bounds: Range<Int>) -> Self {
     let newStart = unsafe _pointer?.advanced(by: bounds.lowerBound)
     let newSpan = unsafe RawSpan(_unchecked: newStart, byteCount: bounds.count)
     return unsafe _overrideLifetime(newSpan, copying: self)
   }
 
+  @unsafe
+  @available(*, deprecated, renamed: "extracting(unchecked:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(unchecked bounds: Range<Int>) -> Self {
+    unsafe extracting(unchecked: bounds)
+  }
+
   /// Constructs a new span over the bytes within the supplied range of
   /// positions within this span.
   ///
@@ -421,8 +441,15 @@ extension RawSpan {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
+  public func extracting(_ bounds: some RangeExpression<Int>) -> Self {
+    extracting(bounds.relative(to: byteOffsets))
+  }
+
+  @available(*, deprecated, renamed: "extracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
   public func _extracting(_ bounds: some RangeExpression<Int>) -> Self {
-    _extracting(bounds.relative(to: byteOffsets))
+    extracting(bounds)
   }
 
   /// Constructs a new span over the bytes within the supplied range of
@@ -443,13 +470,21 @@ extension RawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(
+  public func extracting(
     unchecked bounds: ClosedRange<Int>
   ) -> Self {
     let range = unsafe Range(
       _uncheckedBounds: (bounds.lowerBound, bounds.upperBound + 1)
     )
-    return unsafe _extracting(unchecked: range)
+    return unsafe extracting(unchecked: range)
+  }
+
+  @unsafe
+  @available(*, deprecated, renamed: "extracting(unchecked:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(unchecked bounds: ClosedRange<Int>) -> Self {
+    unsafe extracting(unchecked: bounds)
   }
 
   /// Constructs a new span over all the bytes of this span.
@@ -463,12 +498,20 @@ extension RawSpan {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
+  public func extracting(_: UnboundedRange) -> Self {
+    self
+  }
+
+  @available(*, deprecated, renamed: "extracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
   public func _extracting(_: UnboundedRange) -> Self {
     self
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
 
   /// Calls the given closure with a pointer to the underlying bytes of
@@ -498,7 +541,8 @@ extension RawSpan {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
 
   /// View the bytes of this span as type `T`
@@ -530,7 +574,8 @@ extension RawSpan {
 }
 
 // MARK: load
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
 
   /// Returns a new instance of the given type, constructed from the raw memory
@@ -553,7 +598,7 @@ extension RawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   public func unsafeLoad<T>(
-    fromByteOffset offset: Int = 0, as: T.Type
+    fromByteOffset offset: Int = 0, as type: T.Type
   ) -> T {
     _precondition(
       UInt(bitPattern: offset) <= UInt(bitPattern: _count) &&
@@ -584,7 +629,7 @@ extension RawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   public func unsafeLoad<T>(
-    fromUncheckedByteOffset offset: Int, as: T.Type
+    fromUncheckedByteOffset offset: Int, as type: T.Type
   ) -> T {
     unsafe _start().load(fromByteOffset: offset, as: T.self)
   }
@@ -608,7 +653,7 @@ extension RawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   public func unsafeLoadUnaligned<T: BitwiseCopyable>(
-    fromByteOffset offset: Int = 0, as: T.Type
+    fromByteOffset offset: Int = 0, as type: T.Type
   ) -> T {
     _precondition(
       UInt(bitPattern: offset) <= UInt(bitPattern: _count) &&
@@ -640,13 +685,14 @@ extension RawSpan {
   @unsafe
   @_alwaysEmitIntoClient
   public func unsafeLoadUnaligned<T: BitwiseCopyable>(
-    fromUncheckedByteOffset offset: Int, as: T.Type
+    fromUncheckedByteOffset offset: Int, as type: T.Type
   ) -> T {
     unsafe _start().loadUnaligned(fromByteOffset: offset, as: T.self)
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
   /// Returns a Boolean value indicating whether two `RawSpan` instances
   /// refer to the same region in memory.
@@ -655,14 +701,14 @@ extension RawSpan {
     unsafe (self._pointer == other._pointer) && (self._count == other._count)
   }
 
-  /// Returns the offsets where the memory of `span` is located within
+  /// Returns the offsets where the memory of `other` is located within
   /// the memory represented by `self`
   ///
-  /// Note: `span` must be a subrange of `self`
+  /// Note: `other` must be a subrange of `self`
   ///
-  /// Parameters:
-  /// - span: a subrange of `self`
-  /// Returns: A range of offsets within `self`
+  /// - Parameters:
+  ///   - other: a subrange of `self`
+  /// - Returns: A range of offsets within `self`
   @_alwaysEmitIntoClient
   public func byteOffsets(of other: borrowing Self) -> Range<Int>? {
     if other._count > _count { return nil }
@@ -678,7 +724,8 @@ extension RawSpan {
 }
 
 // MARK: prefixes and suffixes
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension RawSpan {
 
   /// Returns a span containing the initial bytes of this span,
@@ -698,10 +745,18 @@ extension RawSpan {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(first maxLength: Int) -> Self {
+  public func extracting(first maxLength: Int) -> Self {
     _precondition(maxLength >= 0, "Can't have a prefix of negative length")
     let newCount = min(maxLength, byteCount)
-    return unsafe Self(_unchecked: _pointer, byteCount: newCount)
+    let newSpan = unsafe Self(_unchecked: _pointer, byteCount: newCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+  }
+
+  @available(*, deprecated, renamed: "extracting(first:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(first maxLength: Int) -> Self {
+    extracting(first: maxLength)
   }
 
   /// Returns a span over all but the given number of trailing bytes.
@@ -720,11 +775,19 @@ extension RawSpan {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(droppingLast k: Int) -> Self {
+  public func extracting(droppingLast k: Int) -> Self {
     _precondition(k >= 0, "Can't drop a negative number of bytes")
     let droppedCount = min(k, byteCount)
     let count = byteCount &- droppedCount
-    return unsafe Self(_unchecked: _pointer, byteCount: count)
+    let newSpan = unsafe Self(_unchecked: _pointer, byteCount: count)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+  }
+
+  @available(*, deprecated, renamed: "extracting(droppingLast:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(droppingLast k: Int) -> Self {
+    extracting(droppingLast: k)
   }
 
   /// Returns a span containing the trailing bytes of the span,
@@ -744,7 +807,7 @@ extension RawSpan {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(last maxLength: Int) -> Self {
+  public func extracting(last maxLength: Int) -> Self {
     _precondition(maxLength >= 0, "Can't have a suffix of negative length")
     let newCount = min(maxLength, byteCount)
     let newStart = unsafe _pointer?.advanced(by: byteCount &- newCount)
@@ -754,6 +817,13 @@ extension RawSpan {
     return unsafe _overrideLifetime(newSpan, copying: self)
   }
 
+  @available(*, deprecated, renamed: "extracting(last:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(last maxLength: Int) -> Self {
+    extracting(last: maxLength)
+  }
+
   /// Returns a span over all but the given number of initial bytes.
   ///
   /// If the number of elements to drop exceeds the number of bytes in
@@ -770,7 +840,7 @@ extension RawSpan {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(droppingFirst k: Int) -> Self {
+  public func extracting(droppingFirst k: Int) -> Self {
     _precondition(k >= 0, "Can't drop a negative number of bytes")
     let droppedCount = min(k, byteCount)
     let newStart = unsafe _pointer?.advanced(by: droppedCount)
@@ -780,4 +850,11 @@ extension RawSpan {
     // lifetime of 'self'. Make the dependence explicit.
     return unsafe _overrideLifetime(newSpan, copying: self)
   }
+
+  @available(*, deprecated, renamed: "extracting(droppingFirst:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(droppingFirst k: Int) -> Self {
+    extracting(droppingFirst: k)
+  }
 }
diff --git a/stdlib/public/core/Span/Span.swift b/stdlib/public/core/Span/Span.swift
index c2557366dbaf8..f4e84c9389455 100644
--- a/stdlib/public/core/Span/Span.swift
+++ b/stdlib/public/core/Span/Span.swift
@@ -21,19 +21,19 @@ import Swift
 /// When a `Span` is created, it inherits the lifetime of the container
 /// owning the contiguous memory, ensuring temporal safety and avoiding
 /// use-after-free errors. Operations on `Span` are bounds-checked,
-/// ensuring spcial safety and avoiding buffer overflow errors.
+/// ensuring spatial safety and avoiding buffer overflow errors.
 @frozen
 @safe
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 public struct Span<Element: ~Copyable>: ~Escapable, Copyable, BitwiseCopyable {
 
   /// The starting address of this `Span`.
   ///
-  /// `_pointer` can be `nil` if and only if `_count` equals 0.
-  /// Otherwise, `_pointer` must point to memory that will remain
-  /// valid and not mutated as long as this `Span` exists.
-  /// The memory at `_pointer` must be initialized
-  /// as `_count` instances of `Element`.
+  /// If `_count` is zero, `_pointer` may point to valid memory or it may be `nil`,
+  /// but no accesses may be performed through it. Otherwise, `_pointer` must point
+  /// to initialized memory containing `_count` instances of `Element`, which must
+  /// remain valid and not be mutated during the lifetime of this `Span`.
   @usableFromInline
   internal let _pointer: UnsafeRawPointer?
 
@@ -54,7 +54,7 @@ public struct Span<Element: ~Copyable>: ~Escapable, Copyable, BitwiseCopyable {
   @_alwaysEmitIntoClient
   @inline(__always)
   @lifetime(immortal)
-  internal init() {
+  public init() {
     unsafe _pointer = nil
     _count = 0
   }
@@ -85,10 +85,12 @@ public struct Span<Element: ~Copyable>: ~Escapable, Copyable, BitwiseCopyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span: @unchecked Sendable where Element: Sendable & ~Copyable {}
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: ~Copyable {
 
   /// Unsafely create a `Span` over initialized memory.
@@ -165,7 +167,8 @@ extension Span where Element: ~Copyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span /*where Element: Copyable*/ {
 
   /// Unsafely create a `Span` over initialized memory.
@@ -211,7 +214,8 @@ extension Span /*where Element: Copyable*/ {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: BitwiseCopyable {
 
   /// Unsafely create a `Span` over initialized memory.
@@ -374,7 +378,8 @@ extension Span where Element: BitwiseCopyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: ~Copyable {
 
   /// The number of elements in the span.
@@ -385,7 +390,7 @@ extension Span where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @_semantics("fixed_storage.get_count")
-  public var count: Int { _count }
+  public var count: Int { _assumeNonNegative(_count) }
 
   /// A Boolean value indicating whether the span is empty.
   ///
@@ -402,11 +407,12 @@ extension Span where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   public var indices: Range<Index> {
-    unsafe Range(_uncheckedBounds: (0, _count))
+    unsafe Range(_uncheckedBounds: (0, count))
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: ~Copyable {
   @_semantics("fixed_storage.check_index")
   @inline(__always)
@@ -459,7 +465,8 @@ extension Span where Element: ~Copyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: BitwiseCopyable {
   /// Accesses the element at the specified position in the `Span`.
   ///
@@ -495,7 +502,8 @@ extension Span where Element: BitwiseCopyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: BitwiseCopyable {
 
   public var bytes: RawSpan {
@@ -509,7 +517,8 @@ extension Span where Element: BitwiseCopyable {
 }
 
 // MARK: sub-spans
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: ~Copyable {
 
   /// Constructs a new span over the items within the supplied range of
@@ -527,13 +536,20 @@ extension Span where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(_ bounds: Range<Index>) -> Self {
+  public func extracting(_ bounds: Range<Index>) -> Self {
     _precondition(
       UInt(bitPattern: bounds.lowerBound) <= UInt(bitPattern: _count) &&
       UInt(bitPattern: bounds.upperBound) <= UInt(bitPattern: _count),
       "Index range out of bounds"
     )
-    return unsafe _extracting(unchecked: bounds)
+    return unsafe extracting(unchecked: bounds)
+  }
+
+  @available(*, deprecated, renamed: "extracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(_ bounds: Range<Index>) -> Self {
+    extracting(bounds)
   }
 
   /// Constructs a new span over the items within the supplied range of
@@ -554,7 +570,7 @@ extension Span where Element: ~Copyable {
   @unsafe
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(unchecked bounds: Range<Index>) -> Self {
+  public func extracting(unchecked bounds: Range<Index>) -> Self {
     let delta = bounds.lowerBound &* MemoryLayout<Element>.stride
     let newStart = unsafe _pointer?.advanced(by: delta)
     let newSpan = unsafe Span(_unchecked: newStart, count: bounds.count)
@@ -563,6 +579,14 @@ extension Span where Element: ~Copyable {
     return unsafe _overrideLifetime(newSpan, copying: self)
   }
 
+  @unsafe
+  @available(*, deprecated, renamed: "extracting(unchecked:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(unchecked bounds: Range<Index>) -> Self {
+    unsafe extracting(unchecked: bounds)
+  }
+
   /// Constructs a new span over the items within the supplied range of
   /// positions within this span.
   ///
@@ -578,10 +602,17 @@ extension Span where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(
+  public func extracting(
     _ bounds: some RangeExpression<Index>
   ) -> Self {
-    _extracting(bounds.relative(to: indices))
+    extracting(bounds.relative(to: indices))
+  }
+
+  @available(*, deprecated, renamed: "extracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(_ bounds: some RangeExpression<Index>) -> Self {
+    extracting(bounds)
   }
 
   /// Constructs a new span over the items within the supplied range of
@@ -602,13 +633,21 @@ extension Span where Element: ~Copyable {
   @unsafe
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(
+  public func extracting(
     unchecked bounds: ClosedRange<Index>
   ) -> Self {
     let range = unsafe Range(
       _uncheckedBounds: (bounds.lowerBound, bounds.upperBound + 1)
     )
-    return unsafe _extracting(unchecked: range)
+    return unsafe extracting(unchecked: range)
+  }
+
+  @unsafe
+  @available(*, deprecated, renamed: "extracting(unchecked:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(unchecked bounds: ClosedRange<Index>) -> Self {
+    unsafe extracting(unchecked: bounds)
   }
 
   /// Constructs a new span over all the items of this span.
@@ -622,13 +661,21 @@ extension Span where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
+  public func extracting(_: UnboundedRange) -> Self {
+    self
+  }
+
+  @available(*, deprecated, renamed: "extracting(_:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
   public func _extracting(_: UnboundedRange) -> Self {
     self
   }
 }
 
 // MARK: UnsafeBufferPointer access hatch
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: ~Copyable  {
 
   /// Calls a closure with a pointer to the viewed contiguous storage.
@@ -661,7 +708,8 @@ extension Span where Element: ~Copyable  {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: BitwiseCopyable {
 
   /// Calls the given closure with a pointer to the underlying bytes of
@@ -693,7 +741,8 @@ extension Span where Element: BitwiseCopyable {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: ~Copyable {
   /// Returns a Boolean value indicating whether two `Span` instances
   /// refer to the same region in memory.
@@ -702,12 +751,12 @@ extension Span where Element: ~Copyable {
     unsafe (self._pointer == other._pointer) && (self._count == other._count)
   }
 
-  /// Returns the indices within `self` where the memory represented by `span`
-  /// is located, or `nil` if `span` is not located within `self`.
+  /// Returns the indices within `self` where the memory represented by `other`
+  /// is located, or `nil` if `other` is not located within `self`.
   ///
-  /// Parameters:
-  /// - span: a span that may be a subrange of `self`
-  /// Returns: A range of indices within `self`, or `nil`
+  /// - Parameters:
+  /// - other: a span that may be a subrange of `self`
+  /// - Returns: A range of indices within `self`, or `nil`
   @_alwaysEmitIntoClient
   public func indices(of other: borrowing Self) -> Range<Index>? {
     if other._count > _count { return nil }
@@ -728,7 +777,8 @@ extension Span where Element: ~Copyable {
 }
 
 // MARK: prefixes and suffixes
-@available(SwiftStdlib 6.2, *)
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
 extension Span where Element: ~Copyable {
 
   /// Returns a span containing the initial elements of this span,
@@ -748,10 +798,18 @@ extension Span where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(first maxLength: Int) -> Self {
+  public func extracting(first maxLength: Int) -> Self {
     _precondition(maxLength >= 0, "Can't have a prefix of negative length")
     let newCount = min(maxLength, count)
-    return unsafe Self(_unchecked: _pointer, count: newCount)
+    let newSpan = unsafe Self(_unchecked: _pointer, count: newCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+  }
+
+  @available(*, deprecated, renamed: "extracting(first:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(first maxLength: Int) -> Self {
+    extracting(first: maxLength)
   }
 
   /// Returns a span over all but the given number of trailing elements.
@@ -770,10 +828,18 @@ extension Span where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(droppingLast k: Int) -> Self {
+  public func extracting(droppingLast k: Int) -> Self {
     _precondition(k >= 0, "Can't drop a negative number of elements")
     let droppedCount = min(k, count)
-    return unsafe Self(_unchecked: _pointer, count: count &- droppedCount)
+    let newSpan = unsafe Self(_unchecked: _pointer, count: count &- droppedCount)
+    return unsafe _overrideLifetime(newSpan, copying: self)
+  }
+
+  @available(*, deprecated, renamed: "extracting(droppingLast:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(droppingLast k: Int) -> Self {
+    extracting(droppingLast: k)
   }
 
   /// Returns a span containing the final elements of the span,
@@ -793,7 +859,7 @@ extension Span where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(last maxLength: Int) -> Self {
+  public func extracting(last maxLength: Int) -> Self {
     _precondition(maxLength >= 0, "Can't have a suffix of negative length")
     let newCount = min(maxLength, count)
     let offset = (count &- newCount) * MemoryLayout<Element>.stride
@@ -804,6 +870,13 @@ extension Span where Element: ~Copyable {
     return unsafe _overrideLifetime(newSpan, copying: self)
   }
 
+  @available(*, deprecated, renamed: "extracting(last:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(last maxLength: Int) -> Self {
+    extracting(last: maxLength)
+  }
+
   /// Returns a span over all but the given number of initial elements.
   ///
   /// If the number of elements to drop exceeds the number of elements in
@@ -820,7 +893,7 @@ extension Span where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   @lifetime(copy self)
-  public func _extracting(droppingFirst k: Int) -> Self {
+  public func extracting(droppingFirst k: Int) -> Self {
     _precondition(k >= 0, "Can't drop a negative number of elements")
     let droppedCount = min(k, count)
     let offset = droppedCount &* MemoryLayout<Element>.stride
@@ -831,4 +904,11 @@ extension Span where Element: ~Copyable {
     // lifetime of 'buffer'. Make the dependence explicit.
     return unsafe _overrideLifetime(newSpan, copying: self)
   }
+
+  @available(*, deprecated, renamed: "extracting(droppingFirst:)")
+  @_alwaysEmitIntoClient
+  @lifetime(copy self)
+  public func _extracting(droppingFirst k: Int) -> Self {
+    extracting(droppingFirst: k)
+  }
 }
diff --git a/stdlib/public/core/StaticPrint.swift b/stdlib/public/core/StaticPrint.swift
index 0153014799d63..110ac392a03c9 100644
--- a/stdlib/public/core/StaticPrint.swift
+++ b/stdlib/public/core/StaticPrint.swift
@@ -47,7 +47,7 @@ extension ConstantVPrintFInterpolation {
   public mutating func appendInterpolation(
     _ pointer: @autoclosure @escaping () -> UnsafeRawBufferPointer
   ) {
-    appendInterpolation(pointer().baseAddress!)
+    unsafe appendInterpolation(pointer().baseAddress!)
   }
 
   /// Defines interpolation for UnsafeRawPointer.
@@ -64,7 +64,7 @@ extension ConstantVPrintFInterpolation {
     _ pointer: @autoclosure @escaping () -> UnsafeRawPointer
   ) {
     formatString += "%p"
-    arguments.append(pointer)
+    unsafe arguments.append(pointer)
   }
 }
 
@@ -734,7 +734,7 @@ extension UnsafeRawPointer: CVarArg {
   /// appropriately interpreted by C varargs.
   @inlinable // c-abi
   public var _cVarArgEncoding: [Int] {
-    return _encodeBitsAsWords(self)
+    return unsafe _encodeBitsAsWords(self)
   }
 }
 
@@ -758,8 +758,8 @@ extension ConstantVPrintFArguments {
   @_optimize(none)
   internal mutating func append(_ value: @escaping () -> String) {
     argumentClosures.append({ continuation in
-      value().withCString { str in
-        continuation(str._cVarArgEncoding)
+      unsafe value().withCString { str in
+        unsafe continuation(str._cVarArgEncoding)
       }
     })
   }
@@ -817,15 +817,15 @@ internal func constant_vprintf_backend_recurse(
   if let closure = argumentClosures.first {
     closure { newArg in
       args.append(contentsOf: newArg)
-      constant_vprintf_backend_recurse(
+      unsafe constant_vprintf_backend_recurse(
         fmt: fmt,
         argumentClosures: argumentClosures.dropFirst(),
         args: &args
       )
     }
   } else {
-    _ = withVaList(args) { valist in
-      _swift_stdlib_vprintf(fmt, valist)
+    _ = unsafe withVaList(args) { valist in
+      unsafe _swift_stdlib_vprintf(fmt, valist)
     }
   }
 }
@@ -839,14 +839,14 @@ internal func constant_vprintf_backend(
   if let closure = argumentClosures.first {
     closure { newArg in
       args.append(contentsOf: newArg)
-      constant_vprintf_backend_recurse(
+      unsafe constant_vprintf_backend_recurse(
         fmt: fmt,
         argumentClosures: argumentClosures.dropFirst(),
         args: &args
       )
     }
   } else {
-    constant_vprintf_backend_recurse(
+    unsafe constant_vprintf_backend_recurse(
       fmt: fmt,
       argumentClosures: ArraySlice(argumentClosures),
       args: &args
@@ -864,7 +864,7 @@ public func print(_ message: ConstantVPrintFMessage) {
   let argumentClosures = message.interpolation.arguments.argumentClosures
   if Bool(_builtinBooleanLiteral: Builtin.ifdef_SWIFT_STDLIB_PRINT_DISABLED()) { return }
   let formatStringPointer = _getGlobalStringTablePointer(formatString)
-  constant_vprintf_backend(
+  unsafe constant_vprintf_backend(
     fmt: formatStringPointer,
     argumentClosures: argumentClosures
   )
diff --git a/stdlib/public/core/String.swift b/stdlib/public/core/String.swift
index b4132341e8985..e6715e91cc6ed 100644
--- a/stdlib/public/core/String.swift
+++ b/stdlib/public/core/String.swift
@@ -1112,108 +1112,4 @@ extension String {
   }
 }
 
-extension _StringGutsSlice {
-  internal func _isScalarNFCQC(
-    _ scalar: Unicode.Scalar,
-    _ prevCCC: inout UInt8
-  ) -> Bool {
-    let normData = Unicode._NormData(scalar, fastUpperbound: 0x300)
 
-    if prevCCC > normData.ccc, normData.ccc != 0 {
-      return false
-    }
-
-    if !normData.isNFCQC {
-      return false
-    }
-
-    prevCCC = normData.ccc
-    return true
-  }
-
-  internal func _withNFCCodeUnits(_ f: (UInt8) throws -> Void) rethrows {
-    let substring = String(_guts)[range]
-    // Fast path: If we're already NFC (or ASCII), then we don't need to do
-    // anything at all.
-    if _fastPath(_guts.isNFC) {
-      try substring.utf8.forEach(f)
-      return
-    }
-
-    var isNFCQC = true
-    var prevCCC: UInt8 = 0
-
-    if _guts.isFastUTF8 {
-      _fastNFCCheck(&isNFCQC, &prevCCC)
-
-      // Because we have access to the fastUTF8, we can go through that instead
-      // of accessing the UTF8 view on String.
-      if isNFCQC {
-        try unsafe withFastUTF8 {
-          for unsafe byte in unsafe $0 {
-            try f(byte)
-          }
-        }
-
-        return
-      }
-    } else {
-      for scalar in substring.unicodeScalars {
-        if !_isScalarNFCQC(scalar, &prevCCC) {
-          isNFCQC = false
-          break
-        }
-      }
-
-      if isNFCQC {
-        for byte in substring.utf8 {
-          try f(byte)
-        }
-
-        return
-      }
-    }
-
-    for scalar in substring.unicodeScalars._internalNFC {
-      try scalar.withUTF8CodeUnits {
-        for unsafe byte in unsafe $0 {
-          try f(byte)
-        }
-      }
-    }
-  }
-
-  internal func _fastNFCCheck(_ isNFCQC: inout Bool, _ prevCCC: inout UInt8) {
-    unsafe withFastUTF8 { utf8 in
-      var position = 0
-
-      while position < utf8.count {
-        // If our first byte is less than 0xCC, then it means we're under the
-        // 0x300 scalar value and everything up to 0x300 is NFC already.
-        if unsafe utf8[position] < 0xCC {
-          // If our first byte is less than 0xC0, then it means it is ASCII
-          // and only takes up a single byte.
-          if unsafe utf8[position] < 0xC0 {
-            position &+= 1
-          } else {
-            // Otherwise, this is a 2 byte < 0x300 sequence.
-            position &+= 2
-          }
-          // ASCII always has ccc of 0.
-          prevCCC = 0
-
-          continue
-        }
-
-        let (scalar, len) = unsafe _decodeScalar(utf8, startingAt: position)
-
-        if !_isScalarNFCQC(scalar, &prevCCC) {
-          isNFCQC = false
-          return
-        }
-
-        position &+= len
-      }
-    }
-  }
-}
diff --git a/stdlib/public/core/StringBridge.swift b/stdlib/public/core/StringBridge.swift
index 23ccb8f4db461..d28fb1139d127 100644
--- a/stdlib/public/core/StringBridge.swift
+++ b/stdlib/public/core/StringBridge.swift
@@ -62,6 +62,9 @@ internal typealias _CocoaString = AnyObject
   @objc(newTaggedNSStringWithASCIIBytes_:length_:)
   func createTaggedString(bytes: UnsafePointer<UInt8>,
                           count: Int) -> AnyObject?
+  
+  @objc(isNSString__)
+  func getIsNSString() -> Int8
 }
 
 /*
@@ -105,9 +108,15 @@ internal func _stdlib_binary_CFStringGetLength(
   return _NSStringLen(_objc(source))
 }
 
+@_effects(readonly) private func isNSStringImpl(
+  _ str: _StringSelectorHolder
+) -> Bool {
+  return str.getIsNSString() != 0
+}
+
 @_effects(readonly)
 internal func _isNSString(_ str:AnyObject) -> Bool {
-  return _swift_stdlib_isNSString(str) != 0
+  return isNSStringImpl(_objc(str))
 }
 
 @_effects(readonly)
@@ -287,6 +296,13 @@ internal func _cocoaCStringUsingEncodingTrampoline(
   return unsafe _swift_stdlib_NSStringCStringUsingEncodingTrampoline(string, encoding)
 }
 
+@_effects(readonly)
+internal func _cocoaLengthOfBytesInEncodingTrampoline(
+  _ string: _CocoaString, _ encoding: UInt
+) -> UInt {
+  return _swift_stdlib_NSStringLengthOfBytesInEncodingTrampoline(string, encoding)
+}
+
 @_effects(releasenone)
 internal func _cocoaGetCStringTrampoline(
   _ string: _CocoaString,
@@ -607,31 +623,28 @@ extension String {
 
     _connectOrphanedFoundationSubclassesIfNeeded()
 
-    // Smol ASCII a) may bridge to tagged pointers, b) can't contain a BOM
-    if _guts.isSmallASCII {
-      let maybeTagged = _guts.asSmall.withUTF8 { bufPtr in
-        return unsafe _createCFString(
+    if _guts.isSmall {
+      return unsafe _guts.asSmall.withUTF8 { bufPtr in
+        // Smol ASCII a) may bridge to tagged pointers, b) can't contain a BOM
+        if _guts.isSmallASCII, let result = unsafe _createCFString(
           bufPtr.baseAddress._unsafelyUnwrappedUnchecked,
           bufPtr.count,
           kCFStringEncodingUTF8
-        )
-      }
-      if let tagged = maybeTagged { return tagged }
-    }
-
-    if _guts.isSmall {
-        // We can't form a tagged pointer String, so grow to a non-small String,
+        ) {
+          return result
+        }
+        // We can't form a tagged pointer String, so make a non-small String,
         // and bridge that instead. Also avoids CF deleting any BOM that may be
         // present
-        var copy = self
-        // TODO: small capacity minimum is lifted, just need to make native
-        copy._guts.grow(_SmallString.capacity + 1)
-        _internalInvariant(!copy._guts.isSmall)
-        return copy._bridgeToObjectiveCImpl()
+        return unsafe __StringStorage.create(
+          initializingFrom: bufPtr,
+          codeUnitCapacity: bufPtr.count,
+          isASCII: _guts.isSmallASCII)
+      }
     }
     if _guts._object.isImmortal && !_guts._object.largeFastIsConstantCocoa {
       if _guts.isASCII && _guts._object.isFastZeroTerminated {
-        let ptr = unsafe _guts._object.fastUTF8.baseAddress!
+        let ptr = unsafe _guts._object.fastUTF8.baseAddress._unsafelyUnwrappedUnchecked
         let count = _guts.count
         if let indirect = unsafe _stdlib_binary_createIndirectTaggedPointerNSString(
           ptr: ptr, count: count
diff --git a/stdlib/public/core/StringComparison.swift b/stdlib/public/core/StringComparison.swift
index e5a21c8208a35..59f856662f445 100644
--- a/stdlib/public/core/StringComparison.swift
+++ b/stdlib/public/core/StringComparison.swift
@@ -97,7 +97,7 @@ internal func _stringCompareInternal(
 }
 
 @_effects(readonly)
-private func _stringCompareFastUTF8(
+internal func _stringCompareFastUTF8(
   _ utf8Left: UnsafeBufferPointer<UInt8>,
   _ utf8Right: UnsafeBufferPointer<UInt8>,
   expecting: _StringComparisonResult,
diff --git a/stdlib/public/core/StringCreate.swift b/stdlib/public/core/StringCreate.swift
index b11cdcb199d16..a4ccbbfdcd033 100644
--- a/stdlib/public/core/StringCreate.swift
+++ b/stdlib/public/core/StringCreate.swift
@@ -13,60 +13,126 @@
 //===----------------------------------------------------------------------===//
 
 internal func _allASCII(_ input: UnsafeBufferPointer<UInt8>) -> Bool {
-  if input.isEmpty { return true }
-
-  // NOTE: Avoiding for-in syntax to avoid bounds checks
-  //
-  // TODO(String performance): SIMD-ize
-  //
-  let count = input.count
-  var ptr = unsafe UnsafeRawPointer(input.baseAddress._unsafelyUnwrappedUnchecked)
-
-  let asciiMask64 = 0x8080_8080_8080_8080 as UInt64
-  let asciiMask32 = UInt32(truncatingIfNeeded: asciiMask64)
-  let asciiMask16 = UInt16(truncatingIfNeeded: asciiMask64)
-  let asciiMask8 = UInt8(truncatingIfNeeded: asciiMask64)
-  
-  let end128 = unsafe ptr + count & ~(MemoryLayout<(UInt64, UInt64)>.stride &- 1)
-  let end64 = unsafe ptr + count & ~(MemoryLayout<UInt64>.stride &- 1)
-  let end32 = unsafe ptr + count & ~(MemoryLayout<UInt32>.stride &- 1)
-  let end16 = unsafe ptr + count & ~(MemoryLayout<UInt16>.stride &- 1)
-  let end = unsafe ptr + count
-
-  
-  while unsafe ptr < end128 {
-    let pair = unsafe ptr.loadUnaligned(as: (UInt64, UInt64).self)
-    let result = (pair.0 | pair.1) & asciiMask64
-    guard result == 0 else { return false }
-    unsafe ptr = unsafe ptr + MemoryLayout<(UInt64, UInt64)>.stride
+  //--------------- Implementation building blocks ---------------------------//
+#if arch(arm64_32)
+  typealias Word = UInt64
+#else
+  typealias Word = UInt
+#endif
+  let mask = Word(truncatingIfNeeded: 0x80808080_80808080 as UInt64)
+
+#if (arch(i386) || arch(x86_64)) && SWIFT_STDLIB_ENABLE_VECTOR_TYPES
+  // TODO: Should consider AVX2 / AVX512 / AVX10 path here
+  typealias Block = (SIMD16<UInt8>, SIMD16<UInt8>)
+  @_transparent func pmovmskb(_ vec: SIMD16<UInt8>) -> UInt16 {
+    UInt16(Builtin.bitcast_Vec16xInt1_Int16(
+      Builtin.cmp_slt_Vec16xInt8(vec._storage._value, Builtin.zeroInitializer())
+    ))
+  }
+#elseif (arch(arm64) || arch(arm64_32)) && SWIFT_STDLIB_ENABLE_VECTOR_TYPES
+  typealias Block = (SIMD16<UInt8>, SIMD16<UInt8>)
+  @_transparent func umaxv(_ vec: SIMD16<UInt8>) -> UInt8 {
+    UInt8(Builtin.int_vector_reduce_umax_Vec16xInt8(vec._storage._value))
   }
+#else
+  typealias Block = (Word, Word, Word, Word)
+#endif
   
-  // If we had enough bytes for two iterations of this, we would have hit
-  // the loop above, so we only need to do this once
-  if unsafe ptr < end64 {
-    let value = unsafe ptr.loadUnaligned(as: UInt64.self)
-    guard value & asciiMask64 == 0 else { return false }
-    unsafe ptr = unsafe ptr + MemoryLayout<UInt64>.stride
+  @_transparent
+  func allASCII(wordAt pointer: UnsafePointer<UInt8>) -> Bool {
+    let word = unsafe UnsafeRawPointer(pointer).loadUnaligned(as: Word.self)
+    return word & mask == 0
   }
   
-  if unsafe ptr < end32 {
-    let value = unsafe ptr.loadUnaligned(as: UInt32.self)
-    guard value & asciiMask32 == 0 else { return false }
-    unsafe ptr = unsafe ptr + MemoryLayout<UInt32>.stride
+  @_transparent
+  func allASCII(blockAt pointer: UnsafePointer<UInt8>) -> Bool {
+    let block = unsafe UnsafeRawPointer(pointer).loadUnaligned(as: Block.self)
+#if (arch(i386) || arch(x86_64)) && SWIFT_STDLIB_ENABLE_VECTOR_TYPES
+    return pmovmskb(block.0 | block.1) == 0
+#elseif (arch(arm64) || arch(arm64_32)) && SWIFT_STDLIB_ENABLE_VECTOR_TYPES
+    return umaxv(block.0 | block.1) < 0x80
+#else
+    return (block.0 | block.1 | block.2 | block.3) & mask == 0
+#endif
   }
+  //----------------------- Implementation proper ----------------------------//
+  guard input.count >= MemoryLayout<Word>.size else {
+    // They gave us a region of memory
+    // whose size is as modest as it can be.
+    // We'll check every byte
+    // for the bit of most height
+    // and return if we happen on any
+    //
+    // I'm sorry, I'm sorry, I'm trying to delete it. (This chunk of code, not
+    // the Limerick. I would wager that--at least for Strings--we could
+    // unconditionally load 16B here,¹ because of the small string encoding,
+    // and check them all at once, which would be much more efficient. That
+    // probably has to happen by lifting this check into the SmallString
+    // initializer directly, though.)
+    //
+    // ¹ well, most of the time, which makes it a rather conditional
+    // "unconditionally".
+    return unsafe input.allSatisfy { $0 < 0x80 }
+  }
+  
+  // bytes.count is non-zero, so we can unconditionally unwrap baseAddress.
+  let base = unsafe input.baseAddress._unsafelyUnwrappedUnchecked
+  let n = input.count
+  var i = 0
   
-  if unsafe ptr < end16 {
-    let value = unsafe ptr.loadUnaligned(as: UInt16.self)
-    guard value & asciiMask16 == 0 else { return false }
-    unsafe ptr = unsafe ptr + MemoryLayout<UInt16>.stride
+  guard n >= MemoryLayout<Block>.size else {
+    // The size isn't yet to a block
+    // word-by-word we are forced to walk.
+    // So as to not leave a gap
+    // the last word may lap
+    // the word that we already chalked.
+    //
+    //     0      k      2k     3k      ?k   n-k    n-1
+    //     |      |      |      |       |     |      |
+    //     +------+------+------+       +------+     |
+    //     | word | word | word |  ...  | word |     |
+    //     +------+------+------+       +------+     v
+    //                                        +------+
+    //      possibly overlapping final word > | word |
+    //                                        +------+
+    //
+    // This means that we check any bytes in the overlap region twice, but
+    // that's much preferrable to using smaller accesses to avoid rechecking,
+    // because the entire last word is about as expensive as checking just
+    // one byte would be, and on average there's more than one byte remaining.
+    //
+    // Note that we don't bother trying to align any of these accesses, because
+    // there is minimal benefit to doing so on "modern" OoO cores, which can
+    // handle cacheline-crossing loads at full speed. If the string happens to
+    // be aligned, they'll be aligned, if not, they won't be. It will likely
+    // make sense to add a path that does align everything for more limited
+    // embedded CPUs, though.
+    let k = MemoryLayout<Word>.size
+    let last = n &- k
+    while i < last {
+      guard unsafe allASCII(wordAt: base + i) else { return false }
+      i &+= k
+    }
+    return unsafe allASCII(wordAt: base + last)
   }
-
-  if unsafe ptr < end {
-    let value = unsafe ptr.loadUnaligned(fromByteOffset: 0, as: UInt8.self)
-    guard value & asciiMask8 == 0 else { return false }
+  
+  // check block-by-block, with a possibly overlapping last block to avoid
+  // sub-block cleanup. We should be able to avoid manual index arithmetic
+  // and write this loop and the one above something like the following:
+  //
+  //  return stride(from: 0, to: last, by: k).allSatisfy {
+  //    allASCII(blockAt: base + $0)
+  //  } && allASCII(blockAt: base + last)
+  //
+  // but LLVM leaves one unnecessary conditional operation in the loop
+  // when we do that, so we write them out as while loops instead for now.
+  let k = MemoryLayout<Block>.size
+  let last = n &- k
+  while i < last {
+    guard unsafe allASCII(blockAt: base + i) else { return false }
+    i &+= k
   }
-  unsafe _internalInvariant(ptr == end || ptr + 1 == end)
-  return true
+  return unsafe allASCII(blockAt: base + last)
 }
 
 extension String {
@@ -117,7 +183,7 @@ extension String {
       return unsafe (String._uncheckedFromUTF8(
         input, asciiPreScanResult: extraInfo.isASCII
       ), false)
-    case .error(let initialRange):
+    case .error(_, let initialRange):
         return unsafe (repairUTF8(input, firstKnownBrokenRange: initialRange), true)
     }
   }
@@ -139,7 +205,7 @@ extension String {
         newIsASCII: info.isASCII
       )
       return result.asString
-    case .error(let initialRange):
+    case .error(_, let initialRange):
       defer { _fixLifetime(result) }
       //This could be optimized to use excess tail capacity
       return unsafe repairUTF8(result.codeUnits, firstKnownBrokenRange: initialRange)
@@ -312,9 +378,19 @@ extension String {
   @inline(never) // slow-path
   internal static func _copying(_ str: Substring) -> String {
     if _fastPath(str._wholeGuts.isFastUTF8) {
-      return unsafe str._wholeGuts.withFastUTF8(range: str._offsetRange) {
+      var new = unsafe str._wholeGuts.withFastUTF8(range: str._offsetRange) {
         unsafe String._uncheckedFromUTF8($0)
       }
+#if os(watchOS) && _pointerBitWidth(_32)
+      // Required for compatibility with some small strings that
+      // may be encoded in the 32-bit slice of watchOS binaries.
+      if str._wholeGuts.isSmall,
+         str._wholeGuts.count > _SmallString.contiguousCapacity() {
+        new.reserveCapacity(_SmallString.capacity + 1)
+        return new
+      }
+#endif
+      return new
     }
     return unsafe Array(str.utf8).withUnsafeBufferPointer {
       unsafe String._uncheckedFromUTF8($0)
diff --git a/stdlib/public/core/StringGraphemeBreaking.swift b/stdlib/public/core/StringGraphemeBreaking.swift
index ddbadb2427385..0574eb355beb0 100644
--- a/stdlib/public/core/StringGraphemeBreaking.swift
+++ b/stdlib/public/core/StringGraphemeBreaking.swift
@@ -13,14 +13,18 @@
 import SwiftShims
 
 /// CR and LF are common special cases in grapheme breaking logic
-private var _CR: UInt8 { return 0x0d }
-private var _LF: UInt8 { return 0x0a }
-
-internal func _hasGraphemeBreakBetween(
+private var _CR: UInt8 { return 0x0D }
+private var _LF: UInt8 { return 0x0A }
+
+/// Perform a quick-check to determine if there's a grapheme-break between two
+/// scalars, without consulting the data tables. Returns true if there
+/// definitely is a break, false if there definitely is none, and nil if a
+/// break couldn't be determined
+internal func _quickHasGraphemeBreakBetween(
   _ lhs: Unicode.Scalar, _ rhs: Unicode.Scalar
-) -> Bool {
-
-  // CR-LF is a special case: no break between these
+) -> Bool? {
+  // GB3:
+  //   CR-LF is a special case: no break between these
   if lhs == Unicode.Scalar(_CR) && rhs == Unicode.Scalar(_LF) {
     return false
   }
@@ -80,7 +84,10 @@ internal func _hasGraphemeBreakBetween(
     default: return false
     }
   }
-  return hasBreakWhenPaired(lhs) && hasBreakWhenPaired(rhs)
+  if hasBreakWhenPaired(lhs) && hasBreakWhenPaired(rhs) {
+    return true
+  }
+  return nil
 }
 
 extension _StringGuts {
@@ -513,6 +520,8 @@ extension Unicode {
     internal var _previous: Unicode.Scalar
     internal var _state: _GraphemeBreakingState
 
+    /// Refactoring TODO: should we use a quick check result?
+    ///
     /// Returns a non-nil value if it can be determined whether there is a
     /// grapheme break between `scalar1` and `scalar2` without knowing anything
     /// about the scalars that precede `scalar1`. This can optionally be used as
@@ -523,13 +532,7 @@ extension Unicode {
       between scalar1: Unicode.Scalar,
       and scalar2: Unicode.Scalar
     ) -> Bool? {
-      if scalar1.value == 0xD, scalar2.value == 0xA {
-        return false
-      }
-      if _hasGraphemeBreakBetween(scalar1, scalar2) {
-        return true
-      }
-      return nil
+      _quickHasGraphemeBreakBetween(scalar1, scalar2)
     }
 
     /// Initialize a new character recognizer at the _start of text_ (sot)
@@ -637,59 +640,76 @@ extension _StringGuts {
     nextScalar: (Int) -> (scalar: Unicode.Scalar, end: Int)?
   ) -> Int {
     _internalInvariant(index < endIndex._encodedOffset)
+    return _nextGraphemeClusterBoundary(startingAt: index, nextScalar: nextScalar)
+  }
+}
 
-    // Note: If `index` in't already on a boundary, then starting with an empty
-    // state here sometimes leads to this method returning results that diverge
-    // from the true breaks in the string.
-    var state = _GraphemeBreakingState()
-    var (scalar, index) = nextScalar(index)!
-
-    while true {
-      guard let (scalar2, nextIndex) = nextScalar(index) else { break }
-      if state.shouldBreak(between: scalar, and: scalar2) {
-        break
-      }
-      index = nextIndex
-      scalar = scalar2
+internal func _nextGraphemeClusterBoundary(
+  startingAt index: Int,
+  nextScalar: (Int) -> (scalar: Unicode.Scalar, end: Int)?
+) -> Int {
+
+  // Note: If `index` isn't already on a boundary, then starting with an empty
+  // state here sometimes leads to this method returning results that diverge
+  // from the true breaks in the string.
+  var state = _GraphemeBreakingState()
+  var (scalar, index) = nextScalar(index)!
+
+  while true {
+    guard let (scalar2, nextIndex) = nextScalar(index) else { break }
+    if state.shouldBreak(between: scalar, and: scalar2) {
+      break
     }
-
-    return index
+    index = nextIndex
+    scalar = scalar2
   }
 
-  // Returns the stride of the grapheme cluster ending at offset `index`.
-  //
-  // This method uses `previousScalar` to looks back in the string as far as
-  // necessary to find a correct grapheme cluster boundary, whether or not
-  // `index` happens to be on a boundary itself.
-  internal func previousBoundary(
+  return index
+}
+
+extension _StringGuts {
+  fileprivate func previousBoundary(
     endingAt index: Int,
     previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
   ) -> Int {
-    // FIXME: This requires potentially arbitrary lookback in each iteration,
-    // leading to quadratic behavior in some edge cases. Ideally lookback should
-    // only be done once per cluster (or in the case of RI sequences, once per
-    // flag sequence). One way to avoid most quadratic behavior is to replace
-    // this implementation with a scheme that first searches backwards for a
-    // safe point then iterates forward using the regular `shouldBreak` until we
-    // reach `index`, as recommended in section 6.4 of TR#29.
-    //
-    // https://www.unicode.org/reports/tr29/#Random_Access
+    _previousGraphemeClusterBoundary(endingAt: index, previousScalar: previousScalar)
+  }
 
-    var (scalar2, index) = previousScalar(index)!
+}
 
-    while true {
-      guard let (scalar1, previousIndex) = previousScalar(index) else { break }
-      if shouldBreakWithLookback(
-        between: scalar1, and: scalar2, at: index, with: previousScalar
-      ) {
-        break
-      }
-      index = previousIndex
-      scalar2 = scalar1
-    }
+// Returns the stride of the grapheme cluster ending at offset `index`.
+//
+// This method uses `previousScalar` to looks back in the string as far as
+// necessary to find a correct grapheme cluster boundary, whether or not
+// `index` happens to be on a boundary itself.
+internal func _previousGraphemeClusterBoundary(
+  endingAt index: Int,
+  previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
+) -> Int {
+  // FIXME: This requires potentially arbitrary lookback in each iteration,
+  // leading to quadratic behavior in some edge cases. Ideally lookback should
+  // only be done once per cluster (or in the case of RI sequences, once per
+  // flag sequence). One way to avoid most quadratic behavior is to replace
+  // this implementation with a scheme that first searches backwards for a
+  // safe point then iterates forward using the regular `shouldBreak` until we
+  // reach `index`, as recommended in section 6.4 of TR#29.
+  //
+  // https://www.unicode.org/reports/tr29/#Random_Access
 
-    return index
+  var (scalar2, index) = previousScalar(index)!
+
+  while true {
+    guard let (scalar1, previousIndex) = previousScalar(index) else { break }
+    if _shouldBreakWithLookback(
+      between: scalar1, and: scalar2, at: index, with: previousScalar
+    ) {
+      break
+    }
+    index = previousIndex
+    scalar2 = scalar1
   }
+
+  return index
 }
 
 extension _GraphemeBreakingState {
@@ -708,13 +728,8 @@ extension _GraphemeBreakingState {
     between scalar1: Unicode.Scalar,
     and scalar2: Unicode.Scalar
   ) -> Bool {
-    // GB3
-    if scalar1.value == 0xD, scalar2.value == 0xA {
-      return false
-    }
-
-    if _hasGraphemeBreakBetween(scalar1, scalar2) {
-      return true
+    if let result = _quickHasGraphemeBreakBetween(scalar1, scalar2) {
+      return result
     }
 
     let x = Unicode._GraphemeBreakProperty(from: scalar1)
@@ -868,289 +883,282 @@ extension _GraphemeBreakingState {
   }
 }
 
-extension _StringGuts {
-  // Return true if there is an extended grapheme cluster boundary between two
-  // scalars, with no previous knowledge about preceding scalars.
-  //
-  // This method looks back as far as it needs to determine the correct
-  // placement of boundaries.
-  //
-  // This is based off of the Unicode Annex #29 for [Grapheme Cluster Boundary
-  // Rules](https://unicode.org/reports/tr29/#Grapheme_Cluster_Boundary_Rules).
-  internal func shouldBreakWithLookback(
-    between scalar1: Unicode.Scalar,
-    and scalar2: Unicode.Scalar,
-    at index: Int,
-    with previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
-  ) -> Bool {
-    // GB3
-    if scalar1.value == 0xD, scalar2.value == 0xA {
-      return false
-    }
-
-    if _hasGraphemeBreakBetween(scalar1, scalar2) {
-      return true
-    }
-
-    let x = Unicode._GraphemeBreakProperty(from: scalar1)
-    let y = Unicode._GraphemeBreakProperty(from: scalar2)
+// Return true if there is an extended grapheme cluster boundary between two
+// scalars, with no previous knowledge about preceding scalars.
+//
+// This method looks back as far as it needs to determine the correct
+// placement of boundaries.
+//
+// This is based off of the Unicode Annex #29 for [Grapheme Cluster Boundary
+// Rules](https://unicode.org/reports/tr29/#Grapheme_Cluster_Boundary_Rules).
+fileprivate func _shouldBreakWithLookback(
+  between scalar1: Unicode.Scalar,
+  and scalar2: Unicode.Scalar,
+  at index: Int,
+  with previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
+) -> Bool {
+  if let result = _quickHasGraphemeBreakBetween(scalar1, scalar2) {
+    return result
+  }
 
-    switch (x, y) {
+  let x = Unicode._GraphemeBreakProperty(from: scalar1)
+  let y = Unicode._GraphemeBreakProperty(from: scalar2)
 
-    // Fast path: If we know our scalars have no properties the decision is
-    //            trivial and we don't need to crawl to the default statement.
-    case (.any, .any):
-      return true
+  switch (x, y) {
 
-    // GB4
-    case (.control, _):
-      return true
+  // Fast path: If we know our scalars have no properties the decision is
+  //            trivial and we don't need to crawl to the default statement.
+  case (.any, .any):
+    return true
 
-    // GB5
-    case (_, .control):
-      return true
+  // GB4
+  case (.control, _):
+    return true
 
-    // GB6
-    case (.l, .l),
-         (.l, .v),
-         (.l, .lv),
-         (.l, .lvt):
-      return false
+  // GB5
+  case (_, .control):
+    return true
 
-    // GB7
-    case (.lv, .v),
-         (.v, .v),
-         (.lv, .t),
-         (.v, .t):
-      return false
+  // GB6
+  case (.l, .l),
+       (.l, .v),
+       (.l, .lv),
+       (.l, .lvt):
+    return false
 
-    // GB8
-    case (.lvt, .t),
-         (.t, .t):
-      return false
+  // GB7
+  case (.lv, .v),
+       (.v, .v),
+       (.lv, .t),
+       (.v, .t):
+    return false
 
-    // GB9
-    case (_, .extend),
-         (_, .zwj):
-      return false
+  // GB8
+  case (.lvt, .t),
+       (.t, .t):
+    return false
 
-    // GB9a
-    case (_, .spacingMark):
-      return false
+  // GB9
+  case (_, .extend),
+       (_, .zwj):
+    return false
 
-    // GB9b
-    case (.prepend, _):
-      return false
+  // GB9a
+  case (_, .spacingMark):
+    return false
 
-    // GB11
-    case (.zwj, .extendedPictographic):
-      return !checkIfInEmojiSequence(at: index, with: previousScalar)
+  // GB9b
+  case (.prepend, _):
+    return false
 
-    // GB12 & GB13
-    case (.regionalIndicator, .regionalIndicator):
-      return countRIs(at: index, with: previousScalar)
+  // GB11
+  case (.zwj, .extendedPictographic):
+    return !_checkIfInEmojiSequence(at: index, with: previousScalar)
 
-    // GB999
-    default:
-      // GB9c
-      //
-      // Check if our rhs is an InCB=Consonant first because we can more easily
-      // exit out of this branch in most cases. Otherwise, this is a consonant.
-      // Check that the lhs is an InCB=Extend or InCB=Linker (we have to check
-      // if it's an .extend or .zwj first because _isInCBExtend assumes that it
-      // is true).
-      if scalar2._isInCBConsonant,
-         (x == .extend || x == .zwj),
-         (scalar1._isInCBExtend || scalar1._isInCBLinker) {
-        return !checkIfInIndicSequence(at: index, with: previousScalar)
-      }
+  // GB12 & GB13
+  case (.regionalIndicator, .regionalIndicator):
+    return _countRIs(at: index, with: previousScalar)
 
-      return true
+  // GB999
+  default:
+    // GB9c
+    //
+    // Check if our rhs is an InCB=Consonant first because we can more easily
+    // exit out of this branch in most cases. Otherwise, this is a consonant.
+    // Check that the lhs is an InCB=Extend or InCB=Linker (we have to check
+    // if it's an .extend or .zwj first because _isInCBExtend assumes that it
+    // is true).
+    if scalar2._isInCBConsonant,
+       (x == .extend || x == .zwj),
+       (scalar1._isInCBExtend || scalar1._isInCBLinker) {
+      return !_checkIfInIndicSequence(at: index, with: previousScalar)
     }
+
+    return true
   }
+}
 
-  // When walking backwards, it's impossible to know whether we were in an emoji
-  // sequence without walking further backwards. This walks the string backwards
-  // enough until we figure out whether or not to break our
-  // (.zwj, .extendedPictographic) question. For example:
-  //
-  // Scalar view #1:
-  //
-  //     [.control, .zwj, .extendedPictographic]
-  //                     ^
-  //                     | = To determine whether or not we break here, we need
-  //                         to see the previous scalar's grapheme property.
-  //          ^
-  //          | = This is neither .extendedPictographic nor .extend, thus we
-  //              were never in an emoji sequence, so break between the .zwj
-  //              and .extendedPictographic.
-  //
-  // Scalar view #2:
-  //
-  //     [.extendedPictographic, .zwj, .extendedPictographic]
-  //                                  ^
-  //                                  | = Same as above, move backwards one to
-  //                                      view the previous scalar's property.
-  //                ^
-  //                | = This is an .extendedPictographic, so this indicates that
-  //                    we are in an emoji sequence, so we should NOT break
-  //                    between the .zwj and .extendedPictographic.
-  //
-  // Scalar view #3:
-  //
-  //     [.extendedPictographic, .extend, .extend, .zwj, .extendedPictographic]
-  //                                                    ^
-  //                                                    | = Same as above
-  //                                         ^
-  //                                         | = This is an .extend which means
-  //                                             there is a potential emoji
-  //                                             sequence, walk further backwards
-  //                                             to find an .extendedPictographic.
-  //
-  //                               <-- = Another extend, go backwards more.
-  //                ^
-  //                | = We found our starting .extendedPictographic letting us
-  //                    know that we are in an emoji sequence so our initial
-  //                    break question is answered as NO.
-  internal func checkIfInEmojiSequence(
-    at index: Int,
-    with previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
-  ) -> Bool {
-    guard var i = previousScalar(index)?.start else { return false }
-    while let prev = previousScalar(i) {
-      i = prev.start
-      let gbp = Unicode._GraphemeBreakProperty(from: prev.scalar)
-
-      switch gbp {
-      case .extend:
-        continue
-      case .extendedPictographic:
-        return true
-      default:
-        return false
-      }
+// When walking backwards, it's impossible to know whether we were in an emoji
+// sequence without walking further backwards. This walks the string backwards
+// enough until we figure out whether or not to break our
+// (.zwj, .extendedPictographic) question. For example:
+//
+// Scalar view #1:
+//
+//     [.control, .zwj, .extendedPictographic]
+//                     ^
+//                     | = To determine whether or not we break here, we need
+//                         to see the previous scalar's grapheme property.
+//          ^
+//          | = This is neither .extendedPictographic nor .extend, thus we
+//              were never in an emoji sequence, so break between the .zwj
+//              and .extendedPictographic.
+//
+// Scalar view #2:
+//
+//     [.extendedPictographic, .zwj, .extendedPictographic]
+//                                  ^
+//                                  | = Same as above, move backwards one to
+//                                      view the previous scalar's property.
+//                ^
+//                | = This is an .extendedPictographic, so this indicates that
+//                    we are in an emoji sequence, so we should NOT break
+//                    between the .zwj and .extendedPictographic.
+//
+// Scalar view #3:
+//
+//     [.extendedPictographic, .extend, .extend, .zwj, .extendedPictographic]
+//                                                    ^
+//                                                    | = Same as above
+//                                         ^
+//                                         | = This is an .extend which means
+//                                             there is a potential emoji
+//                                             sequence, walk further backwards
+//                                             to find an .extendedPictographic.
+//
+//                               <-- = Another extend, go backwards more.
+//                ^
+//                | = We found our starting .extendedPictographic letting us
+//                    know that we are in an emoji sequence so our initial
+//                    break question is answered as NO.
+fileprivate func _checkIfInEmojiSequence(
+  at index: Int,
+  with previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
+) -> Bool {
+  guard var i = previousScalar(index)?.start else { return false }
+  while let prev = previousScalar(i) {
+    i = prev.start
+    let gbp = Unicode._GraphemeBreakProperty(from: prev.scalar)
+
+    switch gbp {
+    case .extend:
+      continue
+    case .extendedPictographic:
+      return true
+    default:
+      return false
     }
-    return false
   }
+  return false
+}
 
-  // When walking backwards, it's impossible to know whether we break when we
-  // see our first (InCB=Extend, InCB=Consonant) or (InCB=Linker, InCB=Consonant)
-  // without walking further backwards. This walks the string backwards enough
-  // until we figure out whether or not to break this indic sequence. For example:
-  //
-  // Scalar view #1:
-  //
-  //     [InCB=Linker, InCB=Extend, InCB=Consonant]
-  //                               ^
-  //                               | = To be able to know whether or not to
-  //                                   break these two, we need to walk
-  //                                   backwards to determine if this is a
-  //                                   legitimate indic sequence.
-  //      ^
-  //      | = The scalar sequence ends without a starting InCB=Consonant,
-  //          so this is in fact not an indic sequence, so we can break the two.
-  //
-  // Scalar view #2:
-  //
-  //     [InCB=Consonant, InCB=Linker, InCB=Extend, InCB=Consonant]
-  //                                               ^
-  //                                               | = Same as above
-  //                            ^
-  //                            | = This is a Linker, so we at least have seen
-  //                                1 to be able to return true if we see a
-  //                                consonant later.
-  //         ^
-  //         | = Is a consonant and we've seen a linker, so this is a
-  //             legitimate indic sequence, so do NOT break the initial question.
-  internal func checkIfInIndicSequence(
-    at index: Int,
-    with previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
-  ) -> Bool {
-    guard let p = previousScalar(index) else { return false }
+// When walking backwards, it's impossible to know whether we break when we
+// see our first (InCB=Extend, InCB=Consonant) or (InCB=Linker, InCB=Consonant)
+// without walking further backwards. This walks the string backwards enough
+// until we figure out whether or not to break this indic sequence. For example:
+//
+// Scalar view #1:
+//
+//     [InCB=Linker, InCB=Extend, InCB=Consonant]
+//                               ^
+//                               | = To be able to know whether or not to
+//                                   break these two, we need to walk
+//                                   backwards to determine if this is a
+//                                   legitimate indic sequence.
+//      ^
+//      | = The scalar sequence ends without a starting InCB=Consonant,
+//          so this is in fact not an indic sequence, so we can break the two.
+//
+// Scalar view #2:
+//
+//     [InCB=Consonant, InCB=Linker, InCB=Extend, InCB=Consonant]
+//                                               ^
+//                                               | = Same as above
+//                            ^
+//                            | = This is a Linker, so we at least have seen
+//                                1 to be able to return true if we see a
+//                                consonant later.
+//         ^
+//         | = Is a consonant and we've seen a linker, so this is a
+//             legitimate indic sequence, so do NOT break the initial question.
+fileprivate func _checkIfInIndicSequence(
+  at index: Int,
+  with previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
+) -> Bool {
+  guard let p = previousScalar(index) else { return false }
 
-    var hasSeenInCBLinker = p.scalar._isInCBLinker
-    var i = p.start
+  var hasSeenInCBLinker = p.scalar._isInCBLinker
+  var i = p.start
 
-    while let (scalar, prev) = previousScalar(i) {
-      i = prev
+  while let (scalar, prev) = previousScalar(i) {
+    i = prev
 
-      if scalar._isInCBConsonant {
-        return hasSeenInCBLinker
-      }
+    if scalar._isInCBConsonant {
+      return hasSeenInCBLinker
+    }
 
-      let gbp = Unicode._GraphemeBreakProperty(from: scalar)
+    let gbp = Unicode._GraphemeBreakProperty(from: scalar)
 
-      guard gbp == .extend || gbp == .zwj else {
-        return false
-      }
+    guard gbp == .extend || gbp == .zwj else {
+      return false
+    }
 
-      switch (scalar._isInCBExtend, scalar._isInCBLinker) {
-      case (false, false):
-        return false
+    switch (scalar._isInCBExtend, scalar._isInCBLinker) {
+    case (false, false):
+      return false
 
-      case (false, true):
-        hasSeenInCBLinker = true
+    case (false, true):
+      hasSeenInCBLinker = true
 
-      case (true, false):
-        continue
+    case (true, false):
+      continue
 
-      case (true, true):
-        // This case should never happen, but if it does then just be cautious
-        // and say this is invalid.
-        return false
-      }
+    case (true, true):
+      // This case should never happen, but if it does then just be cautious
+      // and say this is invalid.
+      return false
     }
-
-    return false
   }
 
-  // When walking backwards, it's impossible to know whether we break when we
-  // see our first (.regionalIndicator, .regionalIndicator) without walking
-  // further backwards. This walks the string backwards enough until we figure
-  // out whether or not to break these RIs. For example:
-  //
-  // Scalar view #1:
-  //
-  //     [.control, .regionalIndicator, .regionalIndicator]
-  //                                   ^
-  //                                   | = To be able to know whether or not to
-  //                                       break these two, we need to walk
-  //                                       backwards to determine if there were
-  //                                       any previous .regionalIndicators in
-  //                                       a row.
-  //         ^
-  //         | = Not a .regionalIndicator, so our total riCount is 0 and 0 is
-  //             even thus we do not break.
-  //
-  // Scalar view #2:
-  //
-  //     [.control, .regionalIndicator, .regionalIndicator, .regionalIndicator]
-  //                                                       ^
-  //                                                       | = Same as above
-  //                         ^
-  //                         | = This is a .regionalIndicator, so continue
-  //                             walking backwards for more of them. riCount is
-  //                             now equal to 1.
-  //         ^
-  //         | = Not a .regionalIndicator. riCount = 1 which is odd, so break
-  //             the last two .regionalIndicators.
-  internal func countRIs(
-    at index: Int,
-    with previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
-  ) -> Bool {
-    guard let p = previousScalar(index) else { return false }
-    var i = p.start
-    var riCount = 0
-    while let p = previousScalar(i) {
-      i = p.start
-
-      let gbp = Unicode._GraphemeBreakProperty(from: p.scalar)
-      guard gbp == .regionalIndicator else {
-        break
-      }
+  return false
+}
 
-      riCount += 1
+// When walking backwards, it's impossible to know whether we break when we
+// see our first (.regionalIndicator, .regionalIndicator) without walking
+// further backwards. This walks the string backwards enough until we figure
+// out whether or not to break these RIs. For example:
+//
+// Scalar view #1:
+//
+//     [.control, .regionalIndicator, .regionalIndicator]
+//                                   ^
+//                                   | = To be able to know whether or not to
+//                                       break these two, we need to walk
+//                                       backwards to determine if there were
+//                                       any previous .regionalIndicators in
+//                                       a row.
+//         ^
+//         | = Not a .regionalIndicator, so our total riCount is 0 and 0 is
+//             even thus we do not break.
+//
+// Scalar view #2:
+//
+//     [.control, .regionalIndicator, .regionalIndicator, .regionalIndicator]
+//                                                       ^
+//                                                       | = Same as above
+//                         ^
+//                         | = This is a .regionalIndicator, so continue
+//                             walking backwards for more of them. riCount is
+//                             now equal to 1.
+//         ^
+//         | = Not a .regionalIndicator. riCount = 1 which is odd, so break
+//             the last two .regionalIndicators.
+fileprivate func _countRIs(
+  at index: Int,
+  with previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
+) -> Bool {
+  guard let p = previousScalar(index) else { return false }
+  var i = p.start
+  var riCount = 0
+  while let p = previousScalar(i) {
+    i = p.start
+
+    let gbp = Unicode._GraphemeBreakProperty(from: p.scalar)
+    guard gbp == .regionalIndicator else {
+      break
     }
-    return riCount & 1 != 0
+
+    riCount += 1
   }
+  return riCount & 1 != 0
 }
diff --git a/stdlib/public/core/StringGuts.swift b/stdlib/public/core/StringGuts.swift
index a205bc1dcf32d..4ae5123bc2f44 100644
--- a/stdlib/public/core/StringGuts.swift
+++ b/stdlib/public/core/StringGuts.swift
@@ -17,6 +17,7 @@ import SwiftShims
 // functionality and guidance for efficiently working with Strings.
 //
 @frozen
+@_addressableForDependencies
 public // SPI(corelibs-foundation)
 struct _StringGuts: @unchecked Sendable {
   @usableFromInline
diff --git a/stdlib/public/core/StringIndexValidation.swift b/stdlib/public/core/StringIndexValidation.swift
index 93e363ff0589c..f1f84ee50f955 100644
--- a/stdlib/public/core/StringIndexValidation.swift
+++ b/stdlib/public/core/StringIndexValidation.swift
@@ -400,20 +400,3 @@ extension _StringGuts {
       scalarAlign(validateInclusiveSubscalarIndex_5_7(i)))
   }
 }
-
-// Word index validation (String)
-extension _StringGuts {
-  internal func validateWordIndex(
-    _ i: String.Index
-  ) -> String.Index {
-    return roundDownToNearestWord(scalarAlign(validateSubscalarIndex(i)))
-  }
-
-  internal func validateInclusiveWordIndex(
-    _ i: String.Index
-  ) -> String.Index {
-    return roundDownToNearestWord(
-      scalarAlign(validateInclusiveSubscalarIndex(i))
-    )
-  }
-}
diff --git a/stdlib/public/core/StringInterpolation.swift b/stdlib/public/core/StringInterpolation.swift
index e664f521e4091..62a2d492aa1bf 100644
--- a/stdlib/public/core/StringInterpolation.swift
+++ b/stdlib/public/core/StringInterpolation.swift
@@ -10,11 +10,11 @@
 //
 //===----------------------------------------------------------------------===//
 
-/// Represents a string literal with interpolations while it is being built up.
-/// 
-/// Do not create an instance of this type directly. It is used by the compiler
-/// when you create a string using string interpolation. Instead, use string
-/// interpolation to create a new string by including values, literals,
+/// Represents a string literal with interpolations while it's being built up.
+///
+/// You don't need to create an instance of this type directly. It's used by the
+/// compiler when you create a string using string interpolation. Instead, use
+/// string interpolation to create a new string by including values, literals,
 /// variables, or expressions enclosed in parentheses, prefixed by a
 /// backslash (`\(`...`)`).
 ///
@@ -68,8 +68,8 @@ public struct DefaultStringInterpolation: StringInterpolationProtocol, Sendable
   /// Creates a string interpolation with storage pre-sized for a literal
   /// with the indicated attributes.
   /// 
-  /// Do not call this initializer directly. It is used by the compiler when
-  /// interpreting string interpolations.
+  /// You don't need to call this initializer directly. It's used by the
+  /// compiler when interpreting string interpolations.
   @inlinable
   public init(literalCapacity: Int, interpolationCount: Int) {
     let capacityPerInterpolation = 2
@@ -80,8 +80,8 @@ public struct DefaultStringInterpolation: StringInterpolationProtocol, Sendable
   
   /// Appends a literal segment of a string interpolation.
   /// 
-  /// Do not call this method directly. It is used by the compiler when
-  /// interpreting string interpolations.
+  /// You don't need to call this method directly. It's used by the compiler
+  /// when interpreting string interpolations.
   @inlinable
   public mutating func appendLiteral(_ literal: String) {
     literal.write(to: &self)
@@ -90,8 +90,8 @@ public struct DefaultStringInterpolation: StringInterpolationProtocol, Sendable
   /// Interpolates the given value's textual representation into the
   /// string literal being created.
   /// 
-  /// Do not call this method directly. It is used by the compiler when
-  /// interpreting string interpolations. Instead, use string
+  /// You don't need to call this method directly. It's used by the compiler
+  /// when interpreting string interpolations. Instead, use string
   /// interpolation to create a new string by including values, literals,
   /// variables, or expressions enclosed in parentheses, prefixed by a
   /// backslash (`\(`...`)`).
@@ -114,8 +114,8 @@ public struct DefaultStringInterpolation: StringInterpolationProtocol, Sendable
   /// Interpolates the given value's textual representation into the
   /// string literal being created.
   /// 
-  /// Do not call this method directly. It is used by the compiler when
-  /// interpreting string interpolations. Instead, use string
+  /// You don't need to call this method directly. It's used by the compiler
+  /// when interpreting string interpolations. Instead, use string
   /// interpolation to create a new string by including values, literals,
   /// variables, or expressions enclosed in parentheses, prefixed by a
   /// backslash (`\(`...`)`).
@@ -136,8 +136,8 @@ public struct DefaultStringInterpolation: StringInterpolationProtocol, Sendable
   /// Interpolates the given value's textual representation into the
   /// string literal being created.
   /// 
-  /// Do not call this method directly. It is used by the compiler when
-  /// interpreting string interpolations. Instead, use string
+  /// You don't need to call this method directly. It's used by the compiler
+  /// when interpreting string interpolations. Instead, use string
   /// interpolation to create a new string by including values, literals,
   /// variables, or expressions enclosed in parentheses, prefixed by a
   /// backslash (`\(`...`)`).
@@ -160,8 +160,8 @@ public struct DefaultStringInterpolation: StringInterpolationProtocol, Sendable
   /// Interpolates the given value's textual representation into the
   /// string literal being created.
   /// 
-  /// Do not call this method directly. It is used by the compiler when
-  /// interpreting string interpolations. Instead, use string
+  /// You don't need to call this method directly. It's used by the compiler
+  /// when interpreting string interpolations. Instead, use string
   /// interpolation to create a new string by including values, literals,
   /// variables, or expressions enclosed in parentheses, prefixed by a
   /// backslash (`\(`...`)`).
@@ -197,6 +197,128 @@ public struct DefaultStringInterpolation: StringInterpolationProtocol, Sendable
   }
 }
 
+extension DefaultStringInterpolation {
+  /// Interpolates the given optional value's textual representation, or the
+  /// specified default string, into the string literal being created.
+  ///
+  /// You don't need to call this method directly. It's used by the compiler
+  /// when interpreting string interpolations where you provide a `default`
+  /// parameter. For example, the following code implicitly calls this method,
+  /// using the value of the `default` parameter when `value` is `nil`:
+  ///
+  ///     var age: Int? = 48
+  ///     print("Your age is \(age, default: "unknown")")
+  ///     // Prints: Your age is 48
+  ///     age = nil
+  ///     print("Your age is \(age, default: "unknown")")
+  ///     // Prints: Your age is unknown
+  ///
+  /// - Parameters:
+  ///   - value: The value to include in a string interpolation, if non-`nil`.
+  ///   - default: The string to include if `value` is `nil`.
+  @_alwaysEmitIntoClient
+  public mutating func appendInterpolation<T>(
+    _ value: T?,
+    default: @autoclosure () -> some StringProtocol
+  ) where T: TextOutputStreamable, T: CustomStringConvertible {
+    if let value {
+      self.appendInterpolation(value)
+    } else {
+      self.appendInterpolation(`default`())
+    }
+  }
+
+  /// Interpolates the given optional value's textual representation, or the
+  /// specified default string, into the string literal being created.
+  ///
+  /// You don't need to call this method directly. It's used by the compiler
+  /// when interpreting string interpolations where you provide a `default`
+  /// parameter. For example, the following code implicitly calls this method,
+  /// using the value of the `default` parameter when `value` is `nil`:
+  ///
+  ///     var age: Int? = 48
+  ///     print("Your age is \(age, default: "unknown")")
+  ///     // Prints: Your age is 48
+  ///     age = nil
+  ///     print("Your age is \(age, default: "unknown")")
+  ///     // Prints: Your age is unknown
+  ///
+  /// - Parameters:
+  ///   - value: The value to include in a string interpolation, if non-`nil`.
+  ///   - default: The string to include if `value` is `nil`.
+  @_alwaysEmitIntoClient
+  public mutating func appendInterpolation<T>(
+    _ value: T?,
+    default: @autoclosure () -> some StringProtocol
+  ) where T: TextOutputStreamable {
+    if let value {
+      self.appendInterpolation(value)
+    } else {
+      self.appendInterpolation(`default`())
+    }
+  }
+
+  /// Interpolates the given optional value's textual representation, or the
+  /// specified default string, into the string literal being created.
+  ///
+  /// You don't need to call this method directly. It's used by the compiler
+  /// when interpreting string interpolations where you provide a `default`
+  /// parameter. For example, the following code implicitly calls this method,
+  /// using the value of the `default` parameter when `value` is `nil`:
+  ///
+  ///     var age: Int? = 48
+  ///     print("Your age is \(age, default: "unknown")")
+  ///     // Prints: Your age is 48
+  ///     age = nil
+  ///     print("Your age is \(age, default: "unknown")")
+  ///     // Prints: Your age is unknown
+  ///
+  /// - Parameters:
+  ///   - value: The value to include in a string interpolation, if non-`nil`.
+  ///   - default: The string to include if `value` is `nil`.
+  @_alwaysEmitIntoClient
+  public mutating func appendInterpolation<T>(
+    _ value: T?, 
+    default: @autoclosure () -> some StringProtocol
+  ) where T: CustomStringConvertible {
+    if let value {
+      self.appendInterpolation(value)
+    } else {
+      self.appendInterpolation(`default`())
+    }
+  }
+
+  /// Interpolates the given optional value's textual representation, or the
+  /// specified default string, into the string literal being created.
+  ///
+  /// You don't need to call this method directly. It's used by the compiler
+  /// when interpreting string interpolations where you provide a `default`
+  /// parameter. For example, the following code implicitly calls this method,
+  /// using the value of the `default` parameter when `value` is `nil`:
+  ///
+  ///     var age: Int? = 48
+  ///     print("Your age is \(age, default: "unknown")")
+  ///     // Prints: Your age is 48
+  ///     age = nil
+  ///     print("Your age is \(age, default: "unknown")")
+  ///     // Prints: Your age is unknown
+  ///
+  /// - Parameters:
+  ///   - value: The value to include in a string interpolation, if non-`nil`.
+  ///   - default: The string to include if `value` is `nil`.
+  @_alwaysEmitIntoClient
+  public mutating func appendInterpolation<T>(
+    _ value: T?, 
+    default: @autoclosure () -> some StringProtocol
+  ) {
+    if let value {
+      self.appendInterpolation(value)
+    } else {
+      self.appendInterpolation(`default`())
+    }
+  }
+}
+
 extension DefaultStringInterpolation: CustomStringConvertible {
   @inlinable
   public var description: String {
@@ -220,9 +342,9 @@ extension DefaultStringInterpolation: TextOutputStream {
 extension String {
   /// Creates a new instance from an interpolated string literal.
   /// 
-  /// Do not call this initializer directly. It is used by the compiler when
-  /// you create a string using string interpolation. Instead, use string
-  /// interpolation to create a new string by including values, literals,
+  /// You don't need to call this initializer directly. It's used by the
+  /// compiler when you create a string using string interpolation. Instead, use
+  /// string interpolation to create a new string by including values, literals,
   /// variables, or expressions enclosed in parentheses, prefixed by a
   /// backslash (`\(`...`)`).
   ///
@@ -244,9 +366,9 @@ extension String {
 extension Substring {
   /// Creates a new instance from an interpolated string literal.
   /// 
-  /// Do not call this initializer directly. It is used by the compiler when
-  /// you create a string using string interpolation. Instead, use string
-  /// interpolation to create a new string by including values, literals,
+  /// You don't need to call this initializer directly. It's used by the
+  /// compiler when you create a string using string interpolation. Instead, use
+  /// string interpolation to create a new string by including values, literals,
   /// variables, or expressions enclosed in parentheses, prefixed by a
   /// backslash (`\(`...`)`).
   ///
diff --git a/stdlib/public/core/StringNormalization.swift b/stdlib/public/core/StringNormalization.swift
index a8ee470de41cc..e14e4325afae0 100644
--- a/stdlib/public/core/StringNormalization.swift
+++ b/stdlib/public/core/StringNormalization.swift
@@ -52,3 +52,119 @@ extension UnsafeBufferPointer where Element == UInt8 {
     return unsafe !UTF8.isContinuation(self[offset])
   }
 }
+
+internal func _isScalarNFCQC(
+  _ scalar: Unicode.Scalar,
+  _ prevCCC: inout UInt8
+) -> Bool {
+  let normData = Unicode._NormData(scalar, fastUpperbound: 0x300)
+
+  if prevCCC > normData.ccc, normData.ccc != 0 {
+    return false
+  }
+
+  if !normData.isNFCQC {
+    return false
+  }
+
+  prevCCC = normData.ccc
+  return true
+}
+
+extension _StringGutsSlice {
+  internal func _withNFCCodeUnits(_ f: (UInt8) throws -> Void) rethrows {
+    let substring = String(_guts)[range]
+    // Fast path: If we're already NFC (or ASCII), then we don't need to do
+    // anything at all.
+    if _fastPath(_guts.isNFC) {
+      try substring.utf8.forEach(f)
+      return
+    }
+
+    var isNFCQC = true
+    var prevCCC: UInt8 = 0
+
+    if _guts.isFastUTF8 {
+      _fastNFCCheck(&isNFCQC, &prevCCC)
+
+      // Because we have access to the fastUTF8, we can go through that instead
+      // of accessing the UTF8 view on String.
+      if isNFCQC {
+        try unsafe withFastUTF8 {
+          for unsafe byte in unsafe $0 {
+            try f(byte)
+          }
+        }
+
+        return
+      }
+    } else {
+      for scalar in substring.unicodeScalars {
+        if !_isScalarNFCQC(scalar, &prevCCC) {
+          isNFCQC = false
+          break
+        }
+      }
+
+      if isNFCQC {
+        for byte in substring.utf8 {
+          try f(byte)
+        }
+
+        return
+      }
+    }
+
+    for scalar in substring.unicodeScalars._internalNFC {
+      try scalar.withUTF8CodeUnits {
+        for unsafe byte in unsafe $0 {
+          try f(byte)
+        }
+      }
+    }
+  }
+
+  internal func _fastNFCCheck(_ isNFCQC: inout Bool, _ prevCCC: inout UInt8) {
+    unsafe withFastUTF8 { utf8 in
+      isNFCQC = unsafe _nfcQuickCheck(utf8, prevCCC: &prevCCC)
+    }
+  }
+}
+
+/// Run the Unicode NFC quick check algorithm, returns
+internal func _nfcQuickCheck(
+  _ utf8: UnsafeBufferPointer<UInt8>,
+  prevCCC: inout UInt8
+) -> Bool {
+  var position = 0
+
+  while position < utf8.count {
+    // If our first byte is less than 0xCC, then it means we're under the
+    // 0x300 scalar value and everything up to 0x300 is NFC already.
+    if unsafe utf8[position] < 0xCC {
+      // If our first byte is less than 0xC0, then it means it is ASCII
+      // and only takes up a single byte.
+      if unsafe utf8[position] < 0xC0 {
+        position &+= 1
+      } else {
+        // Otherwise, this is a 2 byte < 0x300 sequence.
+        position &+= 2
+      }
+      // ASCII always has ccc of 0.
+      prevCCC = 0
+
+      continue
+    }
+
+    let (scalar, len) = unsafe _decodeScalar(utf8, startingAt: position)
+
+    guard _isScalarNFCQC(scalar, &prevCCC) else {
+      return false
+    }
+
+    position &+= len
+  }
+
+  return true
+}
+
diff --git a/stdlib/public/core/StringObject.swift b/stdlib/public/core/StringObject.swift
index c59e56eadf4a1..407319916b220 100644
--- a/stdlib/public/core/StringObject.swift
+++ b/stdlib/public/core/StringObject.swift
@@ -1005,7 +1005,7 @@ extension _StringObject {
       _internalInvariantFailure()
     }
     #if !$Embedded
-    return _unsafeUncheckedDowncast(storage, to: __StringStorage.self)
+    return unsafe _unsafeUncheckedDowncast(storage, to: __StringStorage.self)
     #else
     return Builtin.castFromNativeObject(storage)
     #endif
@@ -1044,7 +1044,7 @@ extension _StringObject {
       _internalInvariantFailure()
     }
     #if !$Embedded
-    return _unsafeUncheckedDowncast(storage, to: __SharedStringStorage.self)
+    return unsafe _unsafeUncheckedDowncast(storage, to: __SharedStringStorage.self)
     #else
     return Builtin.castFromNativeObject(storage)
     #endif
@@ -1245,7 +1245,7 @@ extension _StringObject {
       countAndFlags: countAndFlags)
 #elseif _pointerBitWidth(_32) || _pointerBitWidth(_16)
     self.init(
-      variant: .immortal(start: bufPtr.baseAddress._unsafelyUnwrappedUnchecked),
+      variant: unsafe .immortal(start: bufPtr.baseAddress._unsafelyUnwrappedUnchecked),
       discriminator: Nibbles.largeImmortal(),
       countAndFlags: countAndFlags)
 #else
diff --git a/stdlib/public/core/StringProtocol.swift b/stdlib/public/core/StringProtocol.swift
index cc65b223b3a4b..6f9cfa4fc05bb 100644
--- a/stdlib/public/core/StringProtocol.swift
+++ b/stdlib/public/core/StringProtocol.swift
@@ -177,15 +177,27 @@ extension StringProtocol {
 
 // Contiguous UTF-8 strings
 extension String {
-  /// Returns whether this string is capable of providing access to
-  /// validly-encoded UTF-8 contents in contiguous memory in O(1) time.
+  /// Returns whether this string's storage contains
+  /// validly-encoded UTF-8 contents in contiguous memory.
   ///
-  /// Contiguous strings always operate in O(1) time for withUTF8 and always
-  /// give a result for String.UTF8View.withContiguousStorageIfAvailable.
+  /// Contiguous strings always operate in O(1) time for withUTF8, always give
+  /// a result for String.UTF8View.withContiguousStorageIfAvailable, and always
+  /// return a non-nil value from `String._utf8Span` and `String.UTF8View._span`.
   /// Contiguous strings also benefit from fast-paths and better optimizations.
-  ///
   @_alwaysEmitIntoClient
-  public var isContiguousUTF8: Bool { return _guts.isFastUTF8 }
+  public var isContiguousUTF8: Bool {
+    if _guts.isFastUTF8 {
+#if os(watchOS) && _pointerBitWidth(_32)
+      // Required for compatibility with some small strings that
+      // may be encoded in the 32-bit slice of watchOS binaries.
+      if _guts.isSmall && _guts.count > _SmallString.contiguousCapacity() {
+        return false
+      }
+#endif
+      return true
+    }
+    return false
+  }
 
   /// If this string is not contiguous, make it so. If this mutates the string,
   /// it will invalidate any pre-existing indices.
@@ -223,13 +235,14 @@ extension String {
 
 // Contiguous UTF-8 strings
 extension Substring {
-  /// Returns whether this string is capable of providing access to
-  /// validly-encoded UTF-8 contents in contiguous memory in O(1) time.
+  /// Returns whether this string's storage contains
+  /// validly-encoded UTF-8 contents in contiguous memory.
   ///
-  /// Contiguous strings always operate in O(1) time for withUTF8 and always
-  /// give a result for String.UTF8View.withContiguousStorageIfAvailable.
+  /// Contiguous strings always operate in O(1) time for withUTF8, always give
+  /// a result for Substring.UTF8View.withContiguousStorageIfAvailable, and
+  /// always return a non-nil value from `Substring._utf8Span` and
+  /// `Substring.UTF8View._span`.
   /// Contiguous strings also benefit from fast-paths and better optimizations.
-  ///
   @_alwaysEmitIntoClient
   public var isContiguousUTF8: Bool { return self.base.isContiguousUTF8 }
 
diff --git a/stdlib/public/core/StringStorage.swift b/stdlib/public/core/StringStorage.swift
index e0b2e9f723454..4e245ba8f8c0c 100644
--- a/stdlib/public/core/StringStorage.swift
+++ b/stdlib/public/core/StringStorage.swift
@@ -16,6 +16,7 @@
 
 internal protocol _AbstractStringStorage: _NSCopying {
   var asString: String { get }
+  var utf16: String.UTF16View { get }
   var count: Int { get }
   var isASCII: Bool { get }
   var start: UnsafePointer<UInt8> { get }
@@ -26,6 +27,7 @@ internal protocol _AbstractStringStorage: _NSCopying {
 
 internal protocol _AbstractStringStorage {
   var asString: String { get }
+  var utf16: String.UTF16View { get }
   var count: Int { get }
   var isASCII: Bool { get }
   var start: UnsafePointer<UInt8> { get }
@@ -295,6 +297,10 @@ final internal class __StringStorage
     get { String(_StringGuts(self)) }
   }
 
+  @inline(__always)
+  final internal var utf16: String.UTF16View {
+    String.UTF16View(_StringGuts(self))
+  }
 
   private init(_doNotCallMe: ()) {
     _internalInvariantFailure("Use the create method")
@@ -721,6 +727,11 @@ final internal class __SharedStringStorage
       return String(_StringGuts(self))
     }
   }
+  
+  @inline(__always)
+  final internal var utf16: String.UTF16View {
+    String.UTF16View(_StringGuts(self))
+  }
 
   internal init(
     _mortal ptr: UnsafePointer<UInt8>,
diff --git a/stdlib/public/core/StringStorageBridge.swift b/stdlib/public/core/StringStorageBridge.swift
index 788af1a609d44..b5a6c761bb13b 100644
--- a/stdlib/public/core/StringStorageBridge.swift
+++ b/stdlib/public/core/StringStorageBridge.swift
@@ -16,6 +16,8 @@ import SwiftShims
 
 internal var _cocoaASCIIEncoding:UInt { 1 } /* NSASCIIStringEncoding */
 internal var _cocoaUTF8Encoding:UInt { 4 } /* NSUTF8StringEncoding */
+internal var _cocoaUTF16Encoding:UInt { 10 } /* NSUTF16StringEncoding and NSUnicodeStringEncoding*/
+internal var _cocoaMacRomanEncoding:UInt { 30 } /* NSMacOSRomanStringEncoding */
 
 extension String {
   @available(SwiftStdlib 5.6, *)
@@ -41,25 +43,17 @@ extension String {
 
 // ObjC interfaces.
 extension _AbstractStringStorage {
+  
   @inline(__always)
   @_effects(releasenone)
   internal func _getCharacters(
     _ buffer: UnsafeMutablePointer<UInt16>, _ aRange: _SwiftNSRange
   ) {
-    _precondition(aRange.location >= 0 && aRange.length >= 0,
-                  "Range out of bounds")
-    // Note: `count` is counting UTF-8 code units, while `aRange` is measured in
-    // UTF-16 offsets. This precondition is a necessary, but not sufficient test
-    // for validity. (More precise checks are done in UTF16View._nativeCopy.)
-    _precondition(aRange.location + aRange.length <= Int(count),
-                  "Range out of bounds")
-
     let range = unsafe Range(
       _uncheckedBounds: (aRange.location, aRange.location+aRange.length))
-    let str = asString
-    unsafe str._copyUTF16CodeUnits(
+    unsafe utf16._nativeCopy(
       into: UnsafeMutableBufferPointer(start: buffer, count: range.count),
-      range: range)
+      offsetRange: range)
   }
 
   @inline(__always)
@@ -69,13 +63,14 @@ extension _AbstractStringStorage {
   ) -> Int8 {
     switch (encoding, isASCII) {
     case (_cocoaASCIIEncoding, true),
+         (_cocoaMacRomanEncoding, true),
          (_cocoaUTF8Encoding, _):
       guard maxLength >= count + 1 else { return 0 }
       unsafe outputPtr.initialize(from: start, count: count)
       unsafe outputPtr[count] = 0
       return 1
     default:
-      return  unsafe _cocoaGetCStringTrampoline(self, outputPtr, maxLength, encoding)
+      return unsafe _cocoaGetCStringTrampoline(self, outputPtr, maxLength, encoding)
     }
   }
 
@@ -84,12 +79,55 @@ extension _AbstractStringStorage {
   internal func _cString(encoding: UInt) -> UnsafePointer<UInt8>? {
     switch (encoding, isASCII) {
     case (_cocoaASCIIEncoding, true),
+         (_cocoaMacRomanEncoding, true),
          (_cocoaUTF8Encoding, _):
       return unsafe start
     default:
       return unsafe _cocoaCStringUsingEncodingTrampoline(self, encoding)
     }
   }
+  
+  @_effects(readonly)
+  internal func _lengthOfBytes(using encoding: UInt) -> UInt {
+    switch encoding {
+    case _cocoaASCIIEncoding:
+      if unsafe isASCII || _allASCII(UnsafeBufferPointer(start: start, count: count)) {
+        return UInt(count)
+      }
+      return 0
+    case _cocoaUTF8Encoding:
+      return UInt(count)
+    case _cocoaUTF16Encoding:
+      return UInt(UTF16Length) * 2
+    case _cocoaMacRomanEncoding:
+      if unsafe isASCII || _allASCII(UnsafeBufferPointer(start: start, count: count)) {
+        return UInt(count)
+      }
+      fallthrough
+    default:
+      return _cocoaLengthOfBytesInEncodingTrampoline(self, encoding)
+    }
+  }
+  
+  // The caller info isn't useful here anyway because it's never client code,
+  // so this makes sure that _character(at:) doesn't have inlined assertion bits
+  @inline(never)
+  internal func _characterAtIndexOutOfBounds() -> Never {
+    _preconditionFailure("String index is out of bounds")
+  }
+  
+  @inline(__always)
+  @_effects(readonly)
+  internal func _character(at offset: Int) -> UInt16 {
+    if _fastPath(isASCII) {
+      if (_fastPath(offset < count && offset >= 0)) {
+        return unsafe UInt16((start + offset).pointee)
+      }
+      _characterAtIndexOutOfBounds()
+    } else {
+      return utf16[nativeNonASCIIOffset: offset]
+    }
+  }
 
   @_effects(readonly)
   internal func _nativeIsEqual<T:_AbstractStringStorage>(
@@ -132,21 +170,25 @@ extension _AbstractStringStorage {
 
       // At this point we've proven that it is a non-Swift NSString
       let otherUTF16Length = _stdlib_binary_CFStringGetLength(other)
-
+      
+      if UTF16Length != otherUTF16Length {
+        return 0
+      }
+      
       // CFString will only give us ASCII bytes here, but that's fine.
       // We already handled non-ASCII UTF8 strings earlier since they're Swift.
       if let asciiEqual = unsafe withCocoaASCIIPointer(other, work: { (ascii) -> Bool in
-        // UTF16 length == UTF8 length iff ASCII
-        if otherUTF16Length == self.count {
-          return unsafe (start == ascii || (memcmp(start, ascii, self.count) == 0))
-        }
-        return false
+        return unsafe (start == ascii || (memcmp(start, ascii, self.count) == 0))
       }) {
         return asciiEqual ? 1 : 0
       }
-
-      if self.UTF16Length != otherUTF16Length {
-        return 0
+      
+      if let utf16Ptr = unsafe _stdlib_binary_CFStringGetCharactersPtr(other) {
+        let utf16Buffer = unsafe UnsafeBufferPointer(
+          start: utf16Ptr,
+          count: otherUTF16Length
+        )
+        return unsafe utf16.elementsEqual(utf16Buffer) ? 1 : 0
       }
 
       /*
@@ -163,7 +205,11 @@ extension __StringStorage {
   @objc(length)
   final internal var UTF16Length: Int {
     @_effects(readonly) @inline(__always) get {
-      return asString.utf16.count // UTF16View special-cases ASCII for us.
+      // UTF16View does this, but there's still a little overhead
+      if isASCII {
+        return count
+      }
+      return utf16.count
     }
   }
 
@@ -180,8 +226,7 @@ extension __StringStorage {
   @objc(characterAtIndex:)
   @_effects(readonly)
   final internal func character(at offset: Int) -> UInt16 {
-    let str = asString
-    return str.utf16[str._toUTF16Index(offset)]
+    _character(at: offset)
   }
 
   @objc(getCharacters:range:)
@@ -202,6 +247,16 @@ extension __StringStorage {
     }
     return nil
   }
+  
+  @objc(_fastUTF8StringContents:utf8Length:)
+  @_effects(readonly)
+  final internal func _fastUTF8StringContents(
+    _ requiresNulTermination: Int8,
+    _ outUTF8Length: UnsafeMutablePointer<UInt>
+  ) -> UnsafePointer<UInt8>? {
+    unsafe outUTF8Length.pointee = UInt(count)
+    return unsafe start
+  }
 
   @objc(UTF8String)
   @_effects(readonly)
@@ -232,6 +287,12 @@ extension __StringStorage {
       return _cocoaUTF8Encoding
     }
   }
+  
+  @objc(lengthOfBytesUsingEncoding:)
+  @_effects(readonly)
+  final internal func lengthOfBytes(using encoding: UInt) -> UInt {
+    _lengthOfBytes(using: encoding)
+  }
 
   @objc(isEqualToString:)
   @_effects(readonly)
@@ -259,7 +320,11 @@ extension __SharedStringStorage {
   @objc(length)
   final internal var UTF16Length: Int {
     @_effects(readonly) get {
-      return asString.utf16.count // UTF16View special-cases ASCII for us.
+      // UTF16View does this, but there's still a little overhead
+      if isASCII {
+        return count
+      }
+      return utf16.count
     }
   }
 
@@ -276,8 +341,7 @@ extension __SharedStringStorage {
   @objc(characterAtIndex:)
   @_effects(readonly)
   final internal func character(at offset: Int) -> UInt16 {
-    let str = asString
-    return str.utf16[str._toUTF16Index(offset)]
+    _character(at: offset)
   }
 
   @objc(getCharacters:range:)
@@ -297,6 +361,12 @@ extension __SharedStringStorage {
       return _cocoaUTF8Encoding
     }
   }
+  
+  @objc(lengthOfBytesUsingEncoding:)
+  @_effects(readonly)
+  final internal func lengthOfBytes(using encoding: UInt) -> UInt {
+    _lengthOfBytes(using: encoding)
+  }
 
   @objc(_fastCStringContents:)
   @_effects(readonly)
@@ -308,6 +378,16 @@ extension __SharedStringStorage {
     }
     return nil
   }
+  
+  @objc(_fastUTF8StringContents:utf8Length:)
+  @_effects(readonly)
+  final internal func _fastUTF8StringContents(
+    _ requiresNulTermination: Int8,
+    _ outUTF8Length: UnsafeMutablePointer<UInt>
+  ) -> UnsafePointer<UInt8>? {
+    unsafe outUTF8Length.pointee = UInt(count)
+    return unsafe start
+  }
 
   @objc(UTF8String)
   @_effects(readonly)
diff --git a/stdlib/public/core/StringUTF16View.swift b/stdlib/public/core/StringUTF16View.swift
index 923476a975215..f4811c3ac98ba 100644
--- a/stdlib/public/core/StringUTF16View.swift
+++ b/stdlib/public/core/StringUTF16View.swift
@@ -435,6 +435,22 @@ extension String.UTF16View: BidirectionalCollection {
 
     return _foreignSubscript(position: idx)
   }
+  
+  internal subscript(nativeNonASCIIOffset offset: Int) -> UTF16.CodeUnit {
+    @_effects(releasenone) get {
+      let threshold = _breadcrumbStride / 2
+      // Do not use breadcrumbs if directly computing the result is expected
+      // to be cheaper
+      let idx = offset < threshold ?
+        _index(startIndex, offsetBy: offset)._knownUTF8 :
+        _nativeGetIndex(for: offset)
+      _precondition(idx._encodedOffset < _guts.count,
+                    "String index is out of bounds")
+      let scalar = _guts.fastUTF8Scalar(
+        startingAt: _guts.scalarAlign(idx)._encodedOffset)
+      return scalar.utf16[idx.transcodedOffset]
+    }
+  }
 }
 
 extension String.UTF16View {
@@ -948,6 +964,21 @@ extension String.UTF16View {
       fatalError()
     }
   }
+  
+  // See _nativeCopy(into:alignedRange:), except this uses un-verified UTF16
+  // offsets instead of aligned indexes
+  internal func _nativeCopy(
+    into buffer: UnsafeMutableBufferPointer<UInt16>,
+    offsetRange range: Range<Int>
+  ) {
+    let alignedRange = _indexRange(for: range, from: startIndex)
+    _precondition(alignedRange.lowerBound._encodedOffset <= _guts.count &&
+                  alignedRange.upperBound._encodedOffset <= _guts.count,
+      "String index is out of bounds")
+    unsafe _nativeCopy(
+      into: buffer,
+      alignedRange: alignedRange.lowerBound ..< alignedRange.upperBound)
+  }
 
   // Copy (i.e. transcode to UTF-16) our contents into a buffer. `alignedRange`
   // means that the indices are part of the UTF16View.indices -- they are either
@@ -962,16 +993,16 @@ extension String.UTF16View {
       range.lowerBound == _utf16AlignNativeIndex(range.lowerBound))
     _internalInvariant(
       range.upperBound == _utf16AlignNativeIndex(range.upperBound))
-
+    
     if _slowPath(range.isEmpty) { return }
-
+    
     let isASCII = _guts.isASCII
     return unsafe _guts.withFastUTF8 { utf8 in
       var writeIdx = 0
       let writeEnd = buffer.count
       var readIdx = range.lowerBound._encodedOffset
       let readEnd = range.upperBound._encodedOffset
-
+      
       if isASCII {
         _internalInvariant(range.lowerBound.transcodedOffset == 0)
         _internalInvariant(range.upperBound.transcodedOffset == 0)
@@ -984,7 +1015,7 @@ extension String.UTF16View {
         }
         return
       }
-
+      
       // Handle mid-transcoded-scalar initial index
       if _slowPath(range.lowerBound.transcodedOffset != 0) {
         _internalInvariant(range.lowerBound.transcodedOffset == 1)
@@ -995,7 +1026,7 @@ extension String.UTF16View {
         readIdx &+= len
         writeIdx &+= 1
       }
-
+      
       // Transcode middle
       while readIdx < readEnd {
         let (scalar, len) = unsafe _decodeScalar(utf8, startingAt: readIdx)
@@ -1009,13 +1040,13 @@ extension String.UTF16View {
           writeIdx &+= 1
         }
       }
-
+      
       // Handle mid-transcoded-scalar final index
       if _slowPath(range.upperBound.transcodedOffset == 1) {
         _internalInvariant(writeIdx < writeEnd)
         let (scalar, _) = unsafe _decodeScalar(utf8, startingAt: readIdx)
         _internalInvariant(scalar.utf16.count == 2)
-
+        
         // Note: this is intentionally not using the _unchecked subscript.
         // (We rely on debug assertions to catch out of bounds access.)
         unsafe buffer[writeIdx] = scalar.utf16[0]
diff --git a/stdlib/public/core/StringUTF8Validation.swift b/stdlib/public/core/StringUTF8Validation.swift
index cd7003e0a0896..0f629bda56b70 100644
--- a/stdlib/public/core/StringUTF8Validation.swift
+++ b/stdlib/public/core/StringUTF8Validation.swift
@@ -18,7 +18,7 @@ private func _isNotOverlong_F0(_ x: UInt8) -> Bool {
   return (0x90...0xBF).contains(x)
 }
 
-private func _isNotOverlong_F4(_ x: UInt8) -> Bool {
+private func _isNotInvalid_F4(_ x: UInt8) -> Bool {
   return UTF8.isContinuation(x) && x <= 0x8F
 }
 
@@ -26,7 +26,7 @@ private func _isNotOverlong_E0(_ x: UInt8) -> Bool {
   return (0xA0...0xBF).contains(x)
 }
 
-private func _isNotOverlong_ED(_ x: UInt8) -> Bool {
+private func _isNotInvalid_ED(_ x: UInt8) -> Bool {
   return UTF8.isContinuation(x) && x <= 0x9F
 }
 
@@ -34,14 +34,81 @@ internal struct UTF8ExtraInfo: Equatable {
   public var isASCII: Bool
 }
 
+@inline(never) // slow-path
+private func _diagnoseInvalidUTF8MultiByteLeading(
+  _ x: UInt8
+) -> _UTF8EncodingErrorKind {
+  _internalInvariant(x >= 0x80)
+  _internalInvariant(!_isUTF8MultiByteLeading(x))
+  switch x {
+  case 0x80...0xBF:
+    return .unexpectedContinuationByte
+  case 0xC0..<0xC2:
+    return .overlongEncodingByte
+  default:
+    _internalInvariant(x > 0xF4)
+    return .invalidNonSurrogateCodePointByte
+  }
+}
+
 internal enum UTF8ValidationResult {
   case success(UTF8ExtraInfo)
-  case error(toBeReplaced: Range<Int>)
+  case error(
+    kind: _UTF8EncodingErrorKind, toBeReplaced: Range<Int>
+  )
 }
 
-extension UTF8ValidationResult: Equatable {}
+// FIXME: refactor other parts of stdlib to avoid this dumb mirror enum
+//
+// Mirror of UTF8.ValidationError.Kind, available on 6.1
+internal struct _UTF8EncodingErrorKind: Error, Sendable, Hashable
+// TODO: embedded?, Codable
+  , RawRepresentable {
+  internal var rawValue: UInt8
+
+  @available(SwiftStdlib 6.2, *)
+  internal var _publicKind: UTF8.ValidationError.Kind {
+    .init(rawValue: self.rawValue)!
+  }
+
+  @inlinable
+  internal init(rawValue: UInt8) {
+    self.rawValue = rawValue
+  }
+
+  /// A continuation byte (`10xxxxxx`) outside of a multi-byte sequence
+  @_alwaysEmitIntoClient
+  internal static var unexpectedContinuationByte: Self {
+    .init(rawValue: 0)
+  }
+
+  /// A byte in a surrogate code point (`U+D800..U+DFFF`) sequence
+  @_alwaysEmitIntoClient
+  internal static var surrogateCodePointByte: Self {
+    .init(rawValue: 1)
+  }
 
-private struct UTF8ValidationError: Error {}
+  /// A byte in an invalid, non-surrogate code point (`>U+10FFFF`) sequence
+  @_alwaysEmitIntoClient
+  internal static var invalidNonSurrogateCodePointByte: Self {
+    .init(rawValue: 2)
+  }
+
+  /// A byte in an overlong encoding sequence
+  @_alwaysEmitIntoClient
+  internal static var overlongEncodingByte: Self {
+    .init(rawValue: 3)
+  }
+
+  /// A multi-byte sequence that is the start of a valid multi-byte scalar
+  /// but is cut off before ending correctly
+  @_alwaysEmitIntoClient
+  internal static var truncatedScalar: Self {
+    .init(rawValue: 4)
+  }
+}
+
+extension UTF8ValidationResult: Equatable {}
 
 internal func validateUTF8(_ buf: UnsafeBufferPointer<UInt8>) -> UTF8ValidationResult {
   if unsafe _allASCII(buf) {
@@ -51,12 +118,20 @@ internal func validateUTF8(_ buf: UnsafeBufferPointer<UInt8>) -> UTF8ValidationR
   var iter = unsafe buf.makeIterator()
   var lastValidIndex = buf.startIndex
 
-  @inline(__always) func guaranteeIn(_ f: (UInt8) -> Bool) throws(UTF8ValidationError) {
-    guard let cu = unsafe iter.next() else { throw UTF8ValidationError() }
-    guard f(cu) else { throw UTF8ValidationError() }
+  @inline(__always) func guarantee(
+    _ f: (UInt8) -> Bool,
+    _ err: _UTF8EncodingErrorKind
+  ) throws(_UTF8EncodingErrorKind) {
+    guard let cu = unsafe iter.next() else {
+      throw .truncatedScalar
+    }
+    guard f(cu) else {
+      throw err
+    }
   }
-  @inline(__always) func guaranteeContinuation() throws(UTF8ValidationError) {
-    try guaranteeIn(UTF8.isContinuation)
+  @inline(__always) func guaranteeContinuation(
+  ) throws(_UTF8EncodingErrorKind) {
+    try guarantee(UTF8.isContinuation, .truncatedScalar)
   }
 
   func _legacyInvalidLengthCalculation(_ _buffer: (_storage: UInt32, ())) -> Int {
@@ -85,11 +160,11 @@ internal func validateUTF8(_ buf: UnsafeBufferPointer<UInt8>) -> UTF8ValidationR
   func _legacyNarrowIllegalRange(buf: Slice<UnsafeBufferPointer<UInt8>>) -> Range<Int> {
     var reversePacked: UInt32 = 0
     if let third = unsafe buf.dropFirst(2).first {
-      unsafe reversePacked |= UInt32(third)
+      reversePacked |= UInt32(third)
       reversePacked <<= 8
     }
     if let second = unsafe buf.dropFirst().first {
-      unsafe reversePacked |= UInt32(second)
+      reversePacked |= UInt32(second)
       reversePacked <<= 8
     }
     unsafe reversePacked |= UInt32(buf.first!)
@@ -102,8 +177,8 @@ internal func validateUTF8(_ buf: UnsafeBufferPointer<UInt8>) -> UTF8ValidationR
     var endIndex = unsafe buf.startIndex
     var iter = unsafe buf.makeIterator()
     _ = unsafe iter.next()
-    while let cu = unsafe iter.next(), unsafe UTF8.isContinuation(cu) {
-      unsafe endIndex += 1
+    while let cu = unsafe iter.next(), UTF8.isContinuation(cu) {
+      endIndex += 1
       // Unicode's Maximal subpart of an ill-formed subsequence will yield
       // at most 3 bytes of error.
       if unsafe buf.distance(from: buf.startIndex, to: endIndex) >= 3 {
@@ -117,21 +192,40 @@ internal func validateUTF8(_ buf: UnsafeBufferPointer<UInt8>) -> UTF8ValidationR
     return unsafe _legacyNarrowIllegalRange(buf: buf[illegalRange])
   }
 
-  do {
+  do throws(_UTF8EncodingErrorKind) {
+
+    /*
+    The table of valid UTF-8 is:
+
+     ╔════════════════════╦════════╦════════╦════════╦════════╗
+     ║    Scalar value    ║ Byte 0 ║ Byte 1 ║ Byte 2 ║ Byte 3 ║
+     ╠════════════════════╬════════╬════════╬════════╬════════╣
+     ║ U+0000..U+007F     ║ 00..7F ║        ║        ║        ║
+     ║ U+0080..U+07FF     ║ C2..DF ║ Contin ║        ║        ║
+     ║ U+0800..U+0FFF     ║ E0     ║ A0..BF ║ Contin ║        ║
+     ║ U+1000..U+CFFF     ║ E1..EC ║ Contin ║ Contin ║        ║
+     ║ U+D000..U+D7FF     ║ ED     ║ 80..9F ║ Contin ║        ║
+     ║ U+E000..U+FFFF     ║ EE..EF ║ Contin ║ Contin ║        ║
+     ║ U+10000..U+3FFFF   ║ F0     ║ 90..BF ║ Contin ║ Contin ║
+     ║ U+40000..U+FFFFF   ║ F1..F3 ║ Contin ║ Contin ║ Contin ║
+     ║ U+100000..U+10FFFF ║ F4     ║ 80..8F ║ Contin ║ Contin ║
+     ╚════════════════════╩════════╩════════╩════════╩════════╝
+
+     "Contin" is any continuation byte, i.e. 80..BF or 10xxxxxx
+     */
     var isASCII = true
     while let cu = unsafe iter.next() {
       if UTF8.isASCII(cu) { lastValidIndex &+= 1; continue }
       isASCII = false
       if _slowPath(!_isUTF8MultiByteLeading(cu)) {
-        func fail() throws(UTF8ValidationError) { throw UTF8ValidationError() }
-        try fail()
+        throw _diagnoseInvalidUTF8MultiByteLeading(cu)
       }
       switch cu {
       case 0xC2...0xDF:
         try guaranteeContinuation()
         lastValidIndex &+= 2
       case 0xE0:
-        try guaranteeIn(_isNotOverlong_E0)
+        try guarantee(_isNotOverlong_E0, .overlongEncodingByte)
         try guaranteeContinuation()
         lastValidIndex &+= 3
       case 0xE1...0xEC:
@@ -139,7 +233,7 @@ internal func validateUTF8(_ buf: UnsafeBufferPointer<UInt8>) -> UTF8ValidationR
         try guaranteeContinuation()
         lastValidIndex &+= 3
       case 0xED:
-        try guaranteeIn(_isNotOverlong_ED)
+        try guarantee(_isNotInvalid_ED, .surrogateCodePointByte)
         try guaranteeContinuation()
         lastValidIndex &+= 3
       case 0xEE...0xEF:
@@ -147,7 +241,7 @@ internal func validateUTF8(_ buf: UnsafeBufferPointer<UInt8>) -> UTF8ValidationR
         try guaranteeContinuation()
         lastValidIndex &+= 3
       case 0xF0:
-        try guaranteeIn(_isNotOverlong_F0)
+        try guarantee(_isNotOverlong_F0, .overlongEncodingByte)
         try guaranteeContinuation()
         try guaranteeContinuation()
         lastValidIndex &+= 4
@@ -157,7 +251,8 @@ internal func validateUTF8(_ buf: UnsafeBufferPointer<UInt8>) -> UTF8ValidationR
         try guaranteeContinuation()
         lastValidIndex &+= 4
       case 0xF4:
-        try guaranteeIn(_isNotOverlong_F4)
+        try guarantee(
+          _isNotInvalid_F4, .invalidNonSurrogateCodePointByte)
         try guaranteeContinuation()
         try guaranteeContinuation()
         lastValidIndex &+= 4
@@ -167,7 +262,9 @@ internal func validateUTF8(_ buf: UnsafeBufferPointer<UInt8>) -> UTF8ValidationR
     }
     return .success(UTF8ExtraInfo(isASCII: isASCII))
   } catch {
-    return unsafe .error(toBeReplaced: findInvalidRange(buf[lastValidIndex...]))
+    return unsafe .error(
+      kind: error,
+      toBeReplaced: findInvalidRange(buf[lastValidIndex...]))
   }
 }
 
@@ -214,7 +311,7 @@ internal func repairUTF8(_ input: UnsafeBufferPointer<UInt8>, firstKnownBrokenRa
     case .success:
       unsafe result.appendInPlace(remainingInput, isASCII: false)
       return String(result)
-    case .error(let newBrokenRange):
+    case .error(_, let newBrokenRange):
       brokenRange = newBrokenRange
     }
   } while !remainingInput.isEmpty
diff --git a/stdlib/public/core/StringUTF8View.swift b/stdlib/public/core/StringUTF8View.swift
index 349c6a3137a6b..20f97379c460b 100644
--- a/stdlib/public/core/StringUTF8View.swift
+++ b/stdlib/public/core/StringUTF8View.swift
@@ -317,8 +317,35 @@ extension String.UTF8View {
   }
 }
 
+@available(SwiftStdlib 6.2, *)
 extension String.UTF8View {
 
+  @lifetime(borrow self)
+  internal borrowing func _underlyingSpan() -> Span<UTF8.CodeUnit> {
+#if _runtime(_ObjC)
+    // handle non-UTF8 Objective-C bridging cases here
+    if !_guts.isFastUTF8, _guts._object.hasObjCBridgeableObject {
+      let storage = _guts._getOrAllocateAssociatedStorage()
+      let (start, count) = unsafe (storage.start, storage.count)
+      let span = unsafe Span(_unsafeStart: start, count: count)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+#endif // _runtime(_ObjC)
+    let count = _guts.count
+    if _guts.isSmall {
+      let a = Builtin.addressOfBorrow(self)
+      let address = unsafe UnsafePointer<UTF8.CodeUnit>(a)
+      let span = unsafe Span(_unsafeStart: address, count: count)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+    let isFastUTF8 = _guts.isFastUTF8
+    _precondition(isFastUTF8, "String must be contiguous UTF8")
+    let buffer = unsafe _guts._object.fastUTF8
+    let span = unsafe Span(_unsafeElements: buffer)
+    return unsafe _overrideLifetime(span, borrowing: self)
+  }
+
+#if !(os(watchOS) && _pointerBitWidth(_32))
   /// A span over the UTF8 code units that make up this string.
   ///
   /// - Note: In the case of bridged UTF16 String instances (on Apple
@@ -334,30 +361,61 @@ extension String.UTF8View {
   public var span: Span<UTF8.CodeUnit> {
     @lifetime(borrow self)
     borrowing get {
-#if _runtime(_ObjC)
-      // handle non-UTF8 Objective-C bridging cases here
-      if !_guts.isFastUTF8 && _guts._object.hasObjCBridgeableObject {
-        let storage = _guts._getOrAllocateAssociatedStorage()
-        let (start, count) = unsafe (storage.start, storage.count)
-        let span = unsafe Span(_unsafeStart: start, count: count)
-        return unsafe _overrideLifetime(span, borrowing: self)
-      }
-#endif
-      let count = _guts.count
-      if _guts.isSmall {
-        fatalError("Span over the small string form is not supported yet.")
-//        let a = Builtin.addressOfBorrow(self)
-//        let address = unsafe UnsafePointer<UTF8.CodeUnit>(a)
-//        let span = unsafe Span(_unsafeStart: address, count: count)
-//        return unsafe _overrideLifetime(span, borrowing: self)
+      _underlyingSpan()
+    }
+  }
+
+  /// A span over the UTF8 code units that make up this string.
+  ///
+  /// - Note: In the case of bridged UTF16 String instances (on Apple
+  /// platforms,) this property transcodes the code units the first time
+  /// it is called. The transcoded buffer is cached, and subsequent calls
+  /// to `span` can reuse the buffer.
+  ///
+  ///  Returns: a `Span` over the UTF8 code units of this String.
+  ///
+  ///  Complexity: O(1) for native UTF8 Strings,
+  ///  amortized O(1) for bridged UTF16 Strings.
+  @available(SwiftStdlib 6.2, *)
+  public var _span: Span<UTF8.CodeUnit>? {
+    @_alwaysEmitIntoClient @inline(__always)
+    @lifetime(borrow self)
+    borrowing get {
+      span
+    }
+  }
+#else // !(os(watchOS) && _pointerBitWidth(_32))
+  @available(watchOS, unavailable)
+  public var span: Span<UTF8.CodeUnit> {
+    @lifetime(borrow self)
+    borrowing get {
+      fatalError("\(#function) unavailable on 32-bit watchOS")
+    }
+  }
+
+  /// A span over the UTF8 code units that make up this string.
+  ///
+  /// - Note: In the case of bridged UTF16 String instances (on Apple
+  /// platforms,) this property transcodes the code units the first time
+  /// it is called. The transcoded buffer is cached, and subsequent calls
+  /// to `span` can reuse the buffer.
+  ///
+  ///  Returns: a `Span` over the UTF8 code units of this String, or `nil`
+  ///           if the String does not have a contiguous representation.
+  ///
+  ///  Complexity: O(1) for native UTF8 Strings,
+  ///  amortized O(1) for bridged UTF16 Strings.
+  @available(SwiftStdlib 6.2, *)
+  public var _span: Span<UTF8.CodeUnit>? {
+    @lifetime(borrow self)
+    borrowing get {
+      if _guts.isSmall, _guts.count > _SmallString.contiguousCapacity() {
+        return nil
       }
-      _precondition(_guts.isFastUTF8)
-      let buffer = unsafe _guts._object.fastUTF8
-      _internalInvariant(count == buffer.count)
-      let span = unsafe Span(_unsafeElements: buffer)
-      return unsafe _overrideLifetime(span, borrowing: self)
+      return _underlyingSpan()
     }
   }
+#endif // !(os(watchOS) && _pointerBitWidth(_32))
 }
 
 // Index conversions
diff --git a/stdlib/public/core/StringWordBreaking.swift b/stdlib/public/core/StringWordBreaking.swift
index bc98e590e5d76..75564907315d2 100644
--- a/stdlib/public/core/StringWordBreaking.swift
+++ b/stdlib/public/core/StringWordBreaking.swift
@@ -1,683 +1,773 @@
 //===----------------------------------------------------------------------===//
 //
+//
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
+// Copyright (c) 2022 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//
 
-extension _StringGuts {
-  internal func roundDownToNearestWord(
-    _ i: String.Index
-  ) -> String.Index {
-    _internalInvariant(i._encodedOffset <= count)
-
-    let offset = i._encodedOffset
-
-    if offset == 0 || offset == count {
-      return i
+extension Unicode {
+  /// A state machine for recognizing word boundaries in an arbitrary series of
+  /// Unicode scalars, based on the specification in [Unicode Annex
+  /// #29](https://unicode.org/reports/tr29/#Word_Boundary_Rules).
+  ///
+  /// The text segmentation algorithm is not stable, and it allows implementers
+  /// to tailor it to their needs. Accordingly, reported word boundaries may
+  /// vary in arbitrary ways between Unicode implementations and system
+  /// configurations, including between versions of the Swift Standard Library.
+  ///
+  /// To implement the rules as specified, this low-level construct has built-in
+  /// support to defer making a decision on whether there is a word boundary
+  /// between two Unicode scalars until more scalars are fed to the state
+  /// machine; that is to say, it implements limited lookahead. The API surface
+  /// only allows one such candidate position to exist at any given time -- this
+  /// corresponds to allowing looking ahead up to the next word boundary. (In
+  /// the unlikely case the rules evolve to require looking ahead even further,
+  /// then this interface will need to be modified or replaced accordingly.)
+  ///
+  /// To detect word breaks in a sequence of Unicode scalars, feed each of them
+  /// to the recognizer by calling its `hasBreak(before:)` method. The method
+  /// indicates if there is a word break preceding the given scalar, or at a
+  /// previously reported candidate position. When every scalar in the text has
+  /// been fed to the recognizer, the `hasCandidateBreakAtEnd()` method should
+  /// be called to determine if there is a break at the last reported candidate
+  /// position. There is also an (implicit) word break at the end of text
+  /// position.
+  ///
+  /// Note that `_WordRecognizer` does not take or return actual text positions
+  /// (such as a string index); it is entirely independent of the underlying
+  /// text representation, and it is able to work with any container model. (For
+  /// example, it can be used to incrementally recognize word breaks in UTF-16
+  /// data streamed from a network connection, or iterate over word boundaries
+  /// in piecewise contiguous UTF-8 buffers stored in a rope data structure.) Of
+  /// course, it is also possible to use it to detect word breaks in a standard
+  /// `String` value, such as done by this example function:
+  ///
+  ///     func collectWordBreaks(in string: String) -> [String.Index] {
+  ///        var result: [String.Index] = []
+  ///        var recognizer = Unicode._WordRecognizer()
+  ///        var candidate = string.startIndex
+  ///        for i in string.unicodeScalars.indices {
+  ///           let r = recognizer.hasBreak(before: string.unicodeScalars[i])
+  ///           if r.setCandidate { candidate = i }
+  ///           if r.breakAtCandidate { result.append(candidate) }
+  ///           if r.breakHere { result.append(i) }
+  ///        }
+  ///        if recognizer.hasCandidateBreakAtEnd() {
+  ///           result.append(candidate)
+  ///        }
+  ///        result.append(string.endIndex)
+  ///        return result
+  ///     }
+  ///
+  /// When used this way, the state machine is able to efficiently iterate over
+  /// all breaks within the string by visiting each scalar exactly once, without
+  /// any backtracking.
+  ///
+  /// It is also possible to discard the recognizer after each detected
+  /// boundary, reinitializing it from scratch for each iteration step:
+  ///
+  ///     func wordBreak(
+  ///        after knownBreak: String.Index, in string: String
+  ///     ) -> String.Index {
+  ///        var recognizer = Unicode._WordRecognizer(after: string.unicodeScalars[knownBreak])
+  ///        var i = string.unicodeScalars.index(after: knownBreak)
+  ///        var candidate = i
+  ///        while i < string.endIndex {
+  ///           let r = recognizer.hasBreak(before: string.unicodeScalars[i])
+  ///           if r.setCandidate { candidate = i }
+  ///           if r.breakAtCandidate { return candidate }
+  ///           if r.breakHere { return i }
+  ///           string.uncodeScalars.formIndex(after: &i)
+  ///        }
+  ///        if recognizer.hasCandidateBreakAtEnd() {
+  ///           return candidate
+  ///        }
+  ///        return i
+  ///     }
+  ///
+  /// However, note that iterating this way is less efficient, because it
+  /// discards lookahead information -- some scalars will be processed multiple
+  /// times. The rules are carefully constructed so that the algorithm reports
+  /// the same word boundaries whether or not recognizer state is preserved.
+  @available(StdlibDeploymentTarget 6.3, *)
+  public // Core primitive
+  struct _WordRecognizer: Sendable {
+    // FIXME: We also need proper public API for this
+
+    /// The last scalar that was fed to `hasBreak(before:)`.
+    var _prevScalar: Unicode.Scalar
+    /// The cached word break property of `_prevScalar`.
+    var _prevCategory: _WordBreakProperty
+    /// The word break property of the last preceding scalar that wasn't ignored by rule WB4.
+    var _baseCategory: _WordBreakProperty
+    /// The current state of the recognizer.
+    var _state: _State
+
+    /// Initialize a new word recognizer at the _start of text_ (sot)
+    /// position.
+    ///
+    /// The resulting state machine will report a word break before the first
+    /// scalar that is fed to it.
+    public init() {
+      // To avoid having to handle the empty case specially, we use LF as the
+      // placeholder before the first scalar. Per WB3a, we always produce a break
+      // following a line feed.
+      _baseCategory = .newlineCRLF
+      _prevScalar = Unicode.Scalar(0x0A as UInt8)
+      _prevCategory = .newlineCRLF
+      _state = .ordinary
     }
 
-    let start = previousWordIndex(endingAt: offset)
-    let end = nextWordIndex(startingAt: start)
-    _internalInvariant(offset <= end, "Word breaking inconsistency")
-
-    if offset == end {
-      return i
+    /// Initialize a new word recognizer with a state after a previously
+    /// recognized word boundary.
+    ///
+    /// This enables clients to iterate over word boundaries without maintaining
+    /// a persistent recognizer state. However, iterating this way may result in
+    /// an arbitrarily large amount of duplicate work. (This is because the word
+    /// segmentation algorithm requires looking ahead by as much as a full
+    /// word's worth of Unicode scalars, and when the old recognizer is
+    /// discarded, the information thus collected has to be recreated from
+    /// scratch.) Whenever possible, it is therefore preferable to iterate over
+    /// multiple word boundaries using a single recognizer instance.
+    ///
+    /// - Parameter scalar: The Unicode scalar immediately following a known
+    ///    word boundary position.
+    public init(after scalar: Unicode.Scalar) {
+      // We assume that the state machine provides stable results even if the
+      // start position was a retroactive candidate.
+      _prevScalar = scalar
+      _prevCategory = Unicode._WordBreakProperty(from: scalar)
+      _baseCategory = _prevCategory
+      _state = .ordinary
     }
-
-    return String.Index(_encodedOffset: start)
   }
+}
 
-  @inline(never)
-  @_effects(releasenone)
-  internal func nextWordIndex(startingAt i: Int) -> Int {
-    if _slowPath(isForeign) {
-      return _foreignNextWordIndex(startingAt: i)
-    }
-
-    return unsafe withFastUTF8 { utf8 in
-      nextWordBoundary(startingAt: i) {
-        _internalInvariant($0 >= 0)
-
-        guard $0 < utf8.count else {
-          return nil
-        }
-
-        let (scalar, len) = unsafe _decodeScalar(utf8, startingAt: $0)
-        return (scalar, $0 &+ len)
+@available(StdlibDeploymentTarget 6.3, *)
+extension Unicode._WordRecognizer {
+  /// The parts of the word recognizer state that are in addition to saved
+  /// information about previous scalars.
+  ///
+  /// This is used to implement stateful lookahead when a break at a particular
+  /// candidate position may need to be suppressed or activated based on a
+  /// subsequent scalar value. It is also used to keep track of the number of
+  /// contiguous regional indicator scalars we have seen so far.
+  internal enum _State: Int, Sendable {
+    case ordinary
+    case afterWB6 // AHLetter × (MidLetter | MidNumLetQ) AHLetter
+    case afterWB7b // Hebrew_Letter × Double_Quote Hebrew_Letter
+    case afterWB12 // Numeric × (MidNum | MidNumLetQ) Numeric
+    case afterMidFlag // [^RI] (RI RI)* RI × RI
+
+    var hasPendingCandidate: Bool {
+      switch self {
+      case .afterWB6, .afterWB7b, .afterWB12: return true
+      default: return false
       }
     }
   }
 
-  internal func _foreignNextWordIndex(startingAt i: Int) -> Int {
-#if _runtime(_ObjC)
-    return nextWordBoundary(startingAt: i) {
-      _internalInvariant($0 >= 0)
-
-      guard $0 < count else {
-        return nil
-      }
-
-      let scalars = String.UnicodeScalarView(self)
-      let idx = String.Index(_encodedOffset: $0)
-
-      let scalar = scalars[idx]
-      let nextIndex = scalars.index(after: idx)
-
-      return (scalar, nextIndex._encodedOffset)
-    }
-#else
-    fatalError("No foreign strings on this platform in this version of Swift.")
-#endif
+  /// Reject a break at the current position, triggering a break at the current
+  /// candidate (if any).
+  internal mutating func _reject(
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    let breakAtCandidate = _state.hasPendingCandidate
+    _state = .ordinary
+    return (
+      setCandidate: false,
+      breakAtCandidate: breakAtCandidate,
+      breakHere: false)
   }
 
-  internal func previousWordIndex(endingAt i: Int) -> Int {
-    if _slowPath(isForeign) {
-      return _foreignPreviousWordIndex(endingAt: i)
-    }
-
-    return unsafe withFastUTF8 { utf8 in
-      previousWordBoundary(endingAt: i) {
-        _internalInvariant($0 <= count)
-
-        guard $0 > 0 else {
-          return nil
-        }
-
-        let (scalar, len) = unsafe _decodeScalar(utf8, endingAt: $0)
-        return (scalar, $0 &- len)
-      }
-    }
+  /// Skip this position, ignoring the current Unicode scalar.
+  internal mutating func _ignore(
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    // Note: not updating _baseCategory
+    return (setCandidate: false, breakAtCandidate: false, breakHere: false)
   }
 
-  @inline(never)
-  internal func _foreignPreviousWordIndex(endingAt i: Int) -> Int {
-#if _runtime(_ObjC)
-    return previousWordBoundary(endingAt: i) {
-      _internalInvariant($0 <= count)
-
-      guard $0 > 0 else {
-        return nil
-      }
-
-      let scalars = String.UnicodeScalarView(self)
-      let idx = String.Index(_encodedOffset: $0)
-
-      let previousIndex = scalars.index(before: idx)
-      let scalar = scalars[previousIndex]
-
-      return (scalar, previousIndex._encodedOffset)
-    }
-#else
-    fatalError("No foreign strings on this platform in this version of Swift.")
-#endif
+  /// Signal a break at the current position, also triggering a break at the
+  /// current candidate (if any).
+  internal mutating func _accept(
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    // If we have a pending candidate, put a break at it
+    let breakAtCandidate = _state.hasPendingCandidate
+    _state = .ordinary
+    return (
+      setCandidate: false,
+      breakAtCandidate: breakAtCandidate,
+      breakHere: true)
   }
-}
-
-internal enum _WordQuestion {
-  case checkingRegionalIndicator(count: Int, previousRIIndex: Int)
-  case requireAHLetter
-  case requireNumeric
-  case requireHebrewLetter
-}
-
-extension _WordQuestion: Equatable {}
-
-internal struct _WordBreakingState {
-  var constraint: (question: _WordQuestion, index: Int)? = nil
-
-  var index: Int
-
-  var previousIndex: Int? = nil
-  var previousProperty: Unicode._WordBreakProperty? = nil
-
-  // When walking forward in a string, we need to not break on emoji flag
-  // sequences. Emoji flag sequences are composed of 2 regional indicators, so
-  // when we see our first (.regionalIndicator, .regionalIndicator) decision,
-  // we need to know to return false in this case. However, if the next scalar
-  // is another regional indicator, we reach the same decision rule, but in this
-  // case we actually need to break there's a boundary between emoji flag
-  // sequences.
-  var shouldBreakRI = false
-}
-
-extension _StringGuts {
-  // Returns the stride of the next word at the previous boundary offset.
-  internal func nextWordBoundary(
-    startingAt index: Int,
-    nextScalar: (Int) -> (scalar: Unicode.Scalar, end: Int)?
-  ) -> Int {
-    _precondition(index < endIndex._encodedOffset)
-
-    var (scalar, index) = nextScalar(index)!
-    var state = _WordBreakingState(index: index)
-
-    while let (scalar2, nextIndex) = nextScalar(state.index) {
-      if shouldBreak(between: scalar, and: scalar2, with: &state) {
-        break
-      }
-
-      scalar = scalar2
-      state.index = nextIndex
-    }
-
-    // If we have a leftover constraint, return the index
-    if let constraint = state.constraint {
-      return constraint.index
-    }
 
-    return state.index
+  /// Set the current position as the active break candidate, and transition into the
+  /// specified state.
+  internal mutating func _transition(
+    into state: _State
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    _internalInvariant(_state == .ordinary)
+    _state = state
+    return (setCandidate: true, breakAtCandidate: false, breakHere: false)
   }
 
-  // Returns the stride of the previous word at the current boundary offset.
-  internal func previousWordBoundary(
-    endingAt index: Int,
-    previousScalar: (Int) -> (scalar: Unicode.Scalar, start: Int)?
-  ) -> Int {
-    var (scalar2, index) = previousScalar(index)!
-    var state = _WordBreakingState(index: index)
-
-    while let (scalar, previousIndex) = previousScalar(state.index) {
-      if shouldBreakBackward(between: scalar, and: scalar2, with: &state) {
-        break
-      }
-
-      scalar2 = scalar
-      state.index = previousIndex
-    }
-
-    if let previousIndex = state.previousIndex {
-      return previousIndex
-    }
-
-    if let constraint = state.constraint {
-      if let riIndex = handleRIConstraint(constraint, with: state) {
-        return riIndex
-      }
-
-      return constraint.index
-    }
-
-    return state.index
+  /// If the current state matches the given expectation, suppress a break at
+  /// this position and discard the active candidate; otherwise, report a break
+  /// at both positions.
+  internal mutating func _expect(
+    _ expectedState: _State
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    let breakHere = (_state != expectedState)
+    let breakAtCandidate = breakHere && _state.hasPendingCandidate
+    _state = .ordinary
+    return (
+      setCandidate: false,
+      breakAtCandidate: breakAtCandidate,
+      breakHere: breakHere)
   }
-}
 
-extension _StringGuts {
-  // The "algorithm" that determines whether or not we should break between
-  // certain word break properties.
-  //
-  // This is based off of the Unicode Annex #29 for [Word Boundary
-  // Rules](https://unicode.org/reports/tr29/#Word_Boundary_Rules).
-  internal func shouldBreak(
-    between scalar1: Unicode.Scalar,
-    and scalar2: Unicode.Scalar,
-    with state: inout _WordBreakingState
-  ) -> Bool {
-    // WB3
-    if scalar1.value == 0xD, scalar2.value == 0xA {
-      return false
+  /// Feeds the next scalar to the state machine, reporting if there is a word
+  /// boundary at the current position or a previously reported candidate.
+  ///
+  /// To decide whether there is a word break at the current position, the
+  /// segmentation algorithm sometimes needs to look ahead by visiting
+  /// additional scalars following the break, up to the next word boundary. To
+  /// allow this, the state machine can report that the current position is a
+  /// provisional break "candidate". Clients are expected to remember the
+  /// position of the last reported candidate, so that it can be retroactively
+  /// promoted to a full break as needed.
+  ///
+  /// - Parameter nextScalar: The scalar at the current position in the text.
+  /// - Returns: A triple of Boolean values `setCandidate`, `breakAtCandidate`,
+  ///     `breakHere`. If `setCandidate` is true, then the caller is expected to
+  ///     save the current text position as a potential word boundary. If
+  ///     `breakAtCandidate` is true, then there is a word boundary at the last
+  ///     candidate position. If `breakHere` is true, then there is a word
+  ///     boundary at the current position. The caller is expected to process
+  ///     these three components in this specific order.
+  public mutating func hasBreak(
+    before nextScalar: Unicode.Scalar
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    let nextCategory = Unicode._WordBreakProperty(from: nextScalar)
+    var nextBase = nextCategory
+
+    // FIXME: Implement a proper state machine here, dispatching on
+    // (state, nextProperty), ideally through a static look-up table
+
+    defer {
+      _prevScalar = nextScalar
+      _prevCategory = nextCategory
+      _baseCategory = nextBase
     }
 
-    let x = Unicode._WordBreakProperty(from: scalar1)
-    
-    // WB3a, handled here since we don't need to look up `y` for this
-    if x == .newlineCRLF {
-      return true
-    }
-    
-    let y = Unicode._WordBreakProperty(from: scalar2)
-
-    switch (x, y) {
-
-    // Fast path: If we know our scalars have no properties the decision is
-    //            trivial and we don't need to crawl to the default statement.
-    case (.any, .any):
-      return true
-
-    // WB3b
-    case (_, .newlineCRLF):
-      return true
-
-    // WB3c
-    case (.zwj, .extendedPictographic):
-      return false
+    switch (_prevCategory, nextCategory) {
+    case (.any, .any): // WB999
+      // Fast path: If we know our scalars have no properties then the decision
+      // is trivial and we don't need to crawl to the default statement.
+      return _accept()
+
+    case (.newlineCRLF, _), // WB3a
+         (_, .newlineCRLF): // WB3b
+      if _prevScalar.value == 0xD, nextScalar.value == 0xA { // WB3
+        _internalInvariant(_prevCategory == .newlineCRLF)
+        return _reject()
+      }
+      return _accept()
 
-    // WB3d
-    case (.wSegSpace, .wSegSpace):
-      return false
+    case (.zwj, .extendedPictographic), // WB3c
+         (.wSegSpace, .wSegSpace): // WB3d
+      return _reject()
 
-    // WB4
-    case (_, .format),
+    case (_, .format), // WB4
          (_, .extend),
          (_, .zwj):
-      if x != .format && x != .extend && x != .zwj {
-        state.previousProperty = x
-      }
-
-      return false
+      nextBase = _baseCategory // Cancel _baseCategory update
+      return _ignore()
 
     default:
-      let newX = state.previousProperty ?? x
-
-      return decidePostFormat(between: newX, and: y, with: &state)
+      break
     }
-  }
-
-  internal func decidePostFormat(
-    between x: Unicode._WordBreakProperty,
-    and y: Unicode._WordBreakProperty,
-    with state: inout _WordBreakingState
-  ) -> Bool {
-    state.previousProperty = nil
 
-    switch (x, y) {
-    // WB5
-    case (.aLetter, .aLetter),
+    switch (_baseCategory, nextCategory) {
+    case (.aLetter, .aLetter), // WB5
          (.aLetter, .hebrewLetter),
          (.hebrewLetter, .aLetter),
          (.hebrewLetter, .hebrewLetter):
-      return false
+      return _reject()
 
-    // WB6
-    case (.aLetter, .midLetter),
+    case (.aLetter, .midLetter), // WB6
          (.hebrewLetter, .midLetter),
          (.aLetter, .midNumLet),
          (.hebrewLetter, .midNumLet),
          (.aLetter, .singleQuote):
-      state.constraint = (question: .requireAHLetter, index: state.index)
+      return _transition(into: .afterWB6)
 
-      return false
-
-    // WB7
-    case (.midLetter, .aLetter),
+    case (.midLetter, .aLetter), // WB7
          (.midLetter, .hebrewLetter),
          (.midNumLet, .aLetter),
          (.midNumLet, .hebrewLetter),
          (.singleQuote, .aLetter),
          (.singleQuote, .hebrewLetter):
-      if let constraint = state.constraint {
-        if constraint.question == .requireAHLetter {
-          state.constraint = nil
-          return false
-        }
-
-        state.index = constraint.index
-        return true
-      }
+      return _expect(.afterWB6)
 
-      return true
+    case (.hebrewLetter, .singleQuote): // WB7a
+      return _reject()
 
-    // WB7a
-    case (.hebrewLetter, .singleQuote):
-      return false
+    case (.hebrewLetter, .doubleQuote): // WB7b
+      return _transition(into: .afterWB7b)
 
-    // WB7b
-    case (.hebrewLetter, .doubleQuote):
-      state.constraint = (question: .requireHebrewLetter, index: state.index)
+    case (.doubleQuote, .hebrewLetter): // WB7c
+      return _expect(.afterWB7b)
 
-      return false
+    case (.numeric, .numeric), // WB8
+         (.aLetter, .numeric), // WB9
+         (.hebrewLetter, .numeric), // WB9
+         (.numeric, .aLetter), // WB10
+         (.numeric, .hebrewLetter): // WB10
+      return _reject()
 
-    // WB7c
-    case (.doubleQuote, .hebrewLetter):
-      if let constraint = state.constraint {
-        if constraint.question == .requireHebrewLetter {
-          state.constraint = nil
-          return false
-        }
-
-        state.index = constraint.index
-        return true
-      }
-
-      return true
-
-    // WB8
-    case (.numeric, .numeric):
-      return false
-
-    // WB9
-    case (.aLetter, .numeric),
-         (.hebrewLetter, .numeric):
-      return false
-
-    // WB10
-    case (.numeric, .aLetter),
-         (.numeric, .hebrewLetter):
-      return false
-
-    // WB11
-    case (.midNum, .numeric),
+    case (.midNum, .numeric), // WB11
          (.midNumLet, .numeric),
          (.singleQuote, .numeric):
-      if let constraint = state.constraint {
-        if constraint.question == .requireNumeric {
-          state.constraint = nil
-          return false
-        }
-
-        state.index = constraint.index
-        return true
-      }
-
-      return true
+      return _expect(.afterWB12)
 
-    // WB12
-    case (.numeric, .midNum),
+    case (.numeric, .midNum), // WB12
          (.numeric, .midNumLet),
          (.numeric, .singleQuote):
-      state.constraint = (question: .requireNumeric, index: state.index)
+      return _transition(into: .afterWB12)
 
-      return false
-
-    // WB13
-    case (.katakana, .katakana):
-      return false
-
-    // WB13a
-    case (.aLetter, .extendNumLet),
+    case (.katakana, .katakana), // WB13
+         (.aLetter, .extendNumLet), // WB13a
          (.hebrewLetter, .extendNumLet),
          (.numeric, .extendNumLet),
          (.katakana, .extendNumLet),
-         (.extendNumLet, .extendNumLet):
-      return false
-
-    // WB13b
-    case (.extendNumLet, .aLetter),
+         (.extendNumLet, .extendNumLet),
+         (.extendNumLet, .aLetter), // WB13b
          (.extendNumLet, .hebrewLetter),
          (.extendNumLet, .numeric),
          (.extendNumLet, .katakana):
-      return false
+      return _reject()
 
-    // WB15
-    case (.regionalIndicator, .regionalIndicator):
-      defer {
-        state.shouldBreakRI.toggle()
+    case (.regionalIndicator, .regionalIndicator): // WB15/WB16
+      let breakHere: Bool
+      if _state == .afterMidFlag {
+        _state = .ordinary
+        breakHere = true
+      } else {
+        _state = .afterMidFlag
+        breakHere = false
       }
+      return (setCandidate: false, breakAtCandidate: false, breakHere: breakHere)
 
-      return state.shouldBreakRI
-
-    default:
-      return true
+    default: // WB999
+      return _accept()
     }
   }
+
+  /// Returns true if the previously reported word boundary candidate needs to
+  /// be promoted to a full break if there are no more scalars in the input text.
+  ///
+  /// There is always an (implicit) word boundary at position at the end of
+  /// text, following the last scalar; however, the end may also trigger a
+  /// pending unreported break at the last candidate previously set by
+  /// `hasBreak`. This method returns true in that case, allowing clients to
+  /// reliably detect such boundaries.
+  public func hasCandidateBreakAtEnd() -> Bool {
+    _state.hasPendingCandidate
+  }
 }
 
-extension _StringGuts {
-  // The "algorithm" that determines whether or not we should break between
-  // certain word break properties.
-  //
-  // This is based off of the Unicode Annex #29 for [Word Boundary
-  // Rules](https://unicode.org/reports/tr29/#Word_Boundary_Rules).
-  internal func shouldBreakBackward(
-    between scalar1: Unicode.Scalar,
-    and scalar2: Unicode.Scalar,
-    with state: inout _WordBreakingState
-  ) -> Bool {
-    // WB3
-    if scalar1.value == 0xD, scalar2.value == 0xA {
-      return false
+extension Unicode {
+  /// A state machine for recognizing safe word boundaries in a backward
+  /// sequence of Unicode scalars, based on the specification in [Unicode Annex
+  /// #29](https://unicode.org/reports/tr29/#Word_Boundary_Rules).
+  ///
+  /// The text segmentation algorithm is not stable, and it allows implementers
+  /// to tailor it to their needs. Accordingly, reported word boundaries may
+  /// vary in arbitrary ways between Unicode implementations and system
+  /// configurations, including between versions of the Swift Standard Library.
+  ///
+  /// This is intended to help implement searching for word boundaries near an
+  /// arbitrary position in a middle of a larger text, as described in [section
+  /// 6.4 of Annex #29](https://unicode.org/reports/tr29/#Random_Access). The
+  /// start position may be at at an arbitrary scalar anywhere in the input text
+  /// -- there is no expectation that the first scalar addresses a known word
+  /// boundary. The state machine scans backwards from that position until it
+  /// detects a reliable word boundary.
+  ///
+  /// To detect a word break near a particular position in a series of Unicode
+  /// scalars, start iterating scalars backward from the start position, feeding
+  /// each of them to the `hasGuaranteedBreak(after:)` method. The method
+  /// indicates if there is a word break preceding the given scalar, or at a
+  /// previously reported candidate position. There is always a word break at
+  /// the start of the text; so if we run out of scalars, the start position is
+  /// going to be a suitable safe word boundary.
+  ///
+  /// Note that this construct may skip over an arbitrary number of word
+  /// boundaries while it is searching for a safe break position. Once a safe
+  /// boundary is found, callers are usually expected to use it as the start
+  /// position to iterate forward using the standard segmentation algorithm
+  /// (implemented by `Unicode._WordRecognizer`), for example until they find
+  /// the break nearest to their original start position. In such cases, it is
+  /// usually a good idea to incrementally memoize word boundaries as they are
+  /// detected, to avoid repeating this process on the same positions later.
+  @available(StdlibDeploymentTarget 6.3, *)
+  public // Core primitive
+  struct _RandomAccessWordRecognizer: Sendable {
+    // FIXME: We also need proper public API for this
+
+    /// The last scalar that was fed to `hasGuaranteedBreak`; i.e., the scalar
+    /// immediately following the current one in the text.
+    var _nextScalar: Unicode.Scalar
+    /// The cached word break property of `_nextScalar`.
+    var _nextCategory: _WordBreakProperty
+    /// The word break property of the most recently seen scalar that wasn't
+    /// ignored by rule WB4.
+    var _baseCategory: _WordBreakProperty
+    /// Additional recognizer state.
+    var _state: _State
+    var _hasPendingCandidate: Bool
+
+    /// Initialize a new word recognizer at an arbitrary text position preceding
+    /// the given scalar.
+    public init(before scalar: Unicode.Scalar) {
+      _nextScalar = scalar
+      _nextCategory = Unicode._WordBreakProperty(from: scalar)
+      _baseCategory = _nextCategory
+      _state = .initial
+      _hasPendingCandidate = false
     }
+  }
+}
 
-    let x = Unicode._WordBreakProperty(from: scalar1)
-    let y = Unicode._WordBreakProperty(from: scalar2)
-
-    switch (x, y) {
 
-    // Fast path: If we know our scalars have no properties the decision is
-    //            trivial and we don't need to crawl to the default statement.
-    case (.any, .any):
-      return true
+@available(StdlibDeploymentTarget 6.3, *)
+extension Unicode._RandomAccessWordRecognizer {
+  internal enum _State: Int, Sendable {
+    case initial
+    case ordinary
+    case beforeWB7
+    case beforeWB7c
+    case beforeWB11
 
-    // WB3a and WB3b
-    case (.newlineCRLF, _),
-         (_, .newlineCRLF):
-      return true
+    var hasPendingCandidate: Bool {
+      switch self {
+      case .beforeWB7, .beforeWB7c, .beforeWB11: return true
+      default: return false
+      }
+    }
+  }
 
-    // WB3c
-    case (.zwj, .extendedPictographic):
-      return false
+  internal mutating func _reject(
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    _hasPendingCandidate = false
+    return (setCandidate: false, breakAtCandidate: false, breakHere: false)
+  }
 
-    // WB3d
-    case (.wSegSpace, .wSegSpace):
-      return false
+  internal mutating func _ignore(
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    return (setCandidate: false, breakAtCandidate: false, breakHere: false)
+  }
 
-    // WB4
-    case (.format, _),
-         (.extend, _),
-         (.zwj, _):
-      if y != .format && y != .extend && y != .zwj {
-        state.previousProperty = y
-
-        // If we already have a constraint in flight, then use that as our base
-        // previous index. Otherwise, use where we're at right now.
-        if let constraint = state.constraint {
-          state.previousIndex = constraint.index
-        } else {
-          state.previousIndex = state.index
-        }
-      }
+  internal mutating func _accept(
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    if _hasPendingCandidate {
+      _hasPendingCandidate = false
+      return (setCandidate: false, breakAtCandidate: true, breakHere: false)
+    }
+    return (setCandidate: false, breakAtCandidate: false, breakHere: true)
+  }
 
-      return false
+  internal mutating func _placeCandidate(
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    if _state == .initial {
+      return _reject()
+    }
+    _hasPendingCandidate = true
+    return (setCandidate: true, breakAtCandidate: false, breakHere: false)
+  }
 
-    // WB4
-    case (_, .format),
-         (_, .extend),
-         (_, .zwj):
-      if state.previousProperty != nil {
-        fallthrough
-      }
+  internal mutating func _placeSoftCandidate(
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    if _hasPendingCandidate || _state == .initial {
+      return (false, false, false)
+    }
+    return _placeCandidate()
+  }
 
-      return false
+  public mutating func hasGuaranteedBreak(
+    after previousScalar: Unicode.Scalar
+  ) -> (setCandidate: Bool, breakAtCandidate: Bool, breakHere: Bool) {
+    let prevCategory = Unicode._WordBreakProperty(from: previousScalar)
+    var newState: _State = .ordinary
+    var newBase = prevCategory
+    defer {
+      _nextCategory = prevCategory
+      _nextScalar = previousScalar
+      _baseCategory = newBase
+      _state = newState
+    }
 
-    default:
-      var newY = y
+    switch (prevCategory, _nextCategory) {
+    case (.any, .any): // WB999 shortcut
+      return _accept()
 
-      if let previousProperty = state.previousProperty {
-        newY = previousProperty
+    case (.newlineCRLF, _), // WB3a
+         (_, .newlineCRLF): // WB3b
+      if previousScalar.value == 0xD, _nextScalar.value == 0xA { // WB3
+        return _reject()
       }
+      return _accept()
 
-      return decidePostFormatBackward(between: x, and: newY, with: &state)
-    }
-  }
+    case (.zwj, .extendedPictographic), // WB3c
+         (.wSegSpace, .wSegSpace): // WB3d
+      newBase = _baseCategory
+      newState = _state
+      return _reject()
 
-  internal func decidePostFormatBackward(
-    between x: Unicode._WordBreakProperty,
-    and y: Unicode._WordBreakProperty,
-    with state: inout _WordBreakingState
-  ) -> Bool {
-    state.previousProperty = nil
+    case (.format, _), // WB4
+         (.extend, _),
+         (.zwj, _):
+      newBase = _baseCategory
+      newState = _state
+      if _state == .initial || _nextCategory == .format || _nextCategory == .extend || _nextCategory == .zwj {
+        return _ignore()
+      }
+      return _placeSoftCandidate()
 
-    switch (x, y) {
-    case (.any, .any):
-      return true
+    default:
+      break
+    }
 
-    // WB5
-    case (.aLetter, .aLetter),
+    switch (prevCategory, _baseCategory) {
+    case (.aLetter, .aLetter), // WB5
          (.aLetter, .hebrewLetter),
          (.hebrewLetter, .aLetter),
          (.hebrewLetter, .hebrewLetter):
-      state.previousIndex = nil
-      return false
-
-    // WB6
-    case (.aLetter, .midLetter),
-         (.hebrewLetter, .midLetter),
-         (.aLetter, .midNumLet),
-         (.hebrewLetter, .midNumLet),
-         (.aLetter, .singleQuote):
-      if let constraint = state.constraint {
-        if constraint.question == .requireAHLetter {
-          state.constraint = nil
-          state.previousIndex = nil
-          return false
-        }
-
-        state.index = constraint.index
-        return true
-      }
+      return _reject()
 
-      return true
-
-    // WB7
-    case (.midLetter, .aLetter),
+    case (.midLetter, .aLetter), // WB7
          (.midLetter, .hebrewLetter),
          (.midNumLet, .aLetter),
          (.midNumLet, .hebrewLetter),
          (.singleQuote, .aLetter),
          (.singleQuote, .hebrewLetter):
-      state.constraint = (question: .requireAHLetter, index: state.index)
-
-      return false
-
-    // WB7a
-    case (.hebrewLetter, .singleQuote):
-      state.previousIndex = nil
-      return false
-
-    // WB7b
-    case (.hebrewLetter, .doubleQuote):
-      if let constraint = state.constraint {
-        if constraint.question == .requireHebrewLetter {
-          state.constraint = nil
-          state.previousIndex = nil
-          return false
-        }
-
-        state.index = constraint.index
-        return true
-      }
-
-      return true
+      newState = .beforeWB7
+      return _placeSoftCandidate()
 
-    // WB7c
-    case (.doubleQuote, .hebrewLetter):
-      state.constraint = (question: .requireHebrewLetter, index: state.index)
+    case (.aLetter, .midLetter), // WB6
+         (.hebrewLetter, .midLetter),
+         (.aLetter, .midNumLet),
+         (.hebrewLetter, .midNumLet),
+         (.aLetter, .singleQuote):
+      if _state == .beforeWB7 || _state == .initial {
+        return _reject()
+      }
+      return _accept()
 
-      return false
+    case (.hebrewLetter, .singleQuote): // WB7a
+      return _reject()
 
-    // WB8
-    case (.numeric, .numeric):
-      state.previousIndex = nil
-      return false
+    case (.doubleQuote, .hebrewLetter): // WB7c
+      newState = .beforeWB7c
+      return _placeSoftCandidate()
 
-    // WB9
-    case (.aLetter, .numeric),
-         (.hebrewLetter, .numeric):
-      state.previousIndex = nil
-      return false
+    case (.hebrewLetter, .doubleQuote): // WB7b
+      if _state == .beforeWB7c || _state == .initial {
+        return _reject()
+      }
+      return _accept()
 
-    // WB10
-    case (.numeric, .aLetter),
+    case (.numeric, .numeric), // WB8
+         (.aLetter, .numeric), // WB9
+         (.hebrewLetter, .numeric),
+         (.numeric, .aLetter), // WB10
          (.numeric, .hebrewLetter):
-      state.previousIndex = nil
-      return false
+      return _reject()
 
-    // WB11
-    case (.midNum, .numeric),
+    case (.midNum, .numeric), // WB11
          (.midNumLet, .numeric),
          (.singleQuote, .numeric):
-      state.constraint = (question: .requireNumeric, index: state.index)
-
-      return false
+      newState = .beforeWB11
+      return _placeSoftCandidate()
 
-    // WB12
-    case (.numeric, .midNum),
+    case (.numeric, .midNum), // WB12
          (.numeric, .midNumLet),
          (.numeric, .singleQuote):
-      if let constraint = state.constraint {
-        if constraint.question == .requireNumeric {
-          state.constraint = nil
-          state.previousIndex = nil
-          return false
-        }
-
-        state.index = constraint.index
-        return true
+      if _state == .beforeWB11 || _state == .initial {
+        return _reject()
       }
+      return _accept()
 
-      return true
-
-    // WB13
-    case (.katakana, .katakana):
-      state.previousIndex = nil
-      return false
-
-    // WB13a
-    case (.aLetter, .extendNumLet),
+    case (.katakana, .katakana), // WB13
+         (.aLetter, .extendNumLet), // WB13a
          (.hebrewLetter, .extendNumLet),
          (.numeric, .extendNumLet),
          (.katakana, .extendNumLet),
-         (.extendNumLet, .extendNumLet):
-      state.previousIndex = nil
-      return false
-
-    // WB13b
-    case (.extendNumLet, .aLetter),
+         (.extendNumLet, .extendNumLet),
+         (.extendNumLet, .aLetter), // WB13b
          (.extendNumLet, .hebrewLetter),
          (.extendNumLet, .numeric),
          (.extendNumLet, .katakana):
-      state.previousIndex = nil
-      return false
-
-    // WB15
-    case (.regionalIndicator, .regionalIndicator):
-      var riCount = 0
-      var previousRIIndex = state.index
-      var constraintIndex = state.index
-
-      if let constraint = state.constraint {
-        if case let .checkingRegionalIndicator(count, riIndex) =
-            constraint.question {
-          riCount = count + 1
-          previousRIIndex = count == 0 ? state.index : riIndex
-          constraintIndex = constraint.index
-        }
-      } else {
-        if let previousIndex = state.previousIndex {
-          constraintIndex = previousIndex
-        }
-      }
-
-      state.constraint = (
-        question: .checkingRegionalIndicator(
-          count: riCount,
-          previousRIIndex: previousRIIndex
-        ),
-        index: constraintIndex
-      )
+      return _reject()
 
-      state.previousIndex = nil
+    case (.regionalIndicator, .regionalIndicator): // WB15/WB16
+      return _reject()
 
-      return false
+    case (_, .format),
+         (_, .extend),
+         (_, .zwj):
+      _internalInvariant(!_hasPendingCandidate)
+      newState = .initial
+      return _reject()
 
     default:
-      return true
+      if
+        !_hasPendingCandidate,
+        _nextCategory == .format || _nextCategory == .extend || _nextCategory == .zwj
+      {
+        return _ignore()
+      }
+      return _accept()
     }
   }
+}
 
-  internal func handleRIConstraint(
-    _ constraint: (question: _WordQuestion, index: Int),
-    with state: _WordBreakingState
-  ) -> Int? {
-    if case let .checkingRegionalIndicator(count, previousRIIndex) =
-        constraint.question {
-      // If our count is 0, then we were unable to update previousRIIndex.
-      // However, that index is now equal to state.index.
-      if count == 0 {
-        return state.index
-      }
+extension String {
+  /// Find and return a word boundary position at or before an arbitrary index
+  /// within this string. The result may not be the closest word break to the
+  /// start position.
+  ///
+  /// This implements the core algorithm for finding a "safe" starting point for
+  /// random access to word breaks, following [section 6.4 of Unicode Annex
+  /// #29](https://unicode.org/reports/tr29/#Random_Access). Unicode defines
+  /// word boundaries using a forward-only state machine; this algorithm does
+  /// its best to run the state machine backwards until it finds a guaranteed
+  /// break position.
+  ///
+  /// This process is inherently an approximation: the algorithm may need to
+  /// skip over an arbitrary number of actual word boundaries before finding one
+  /// that it can judge with confidence. This makes it relatively expensive to
+  /// iterate over word boundaries backwards; in the worst case, a naive
+  /// implementation may have quadratic complexity. The recommended way to
+  /// mitigate this is to maintain a cache of word breaks already traversed,
+  /// only calling this method to extend the range of known breaks backwards as
+  /// needed.
+  ///
+  /// - Parameter i: An arbitrary index within the string, not necessarily
+  ///     addressing a word boundary.
+  /// - Returns: A valid index less than equal to the input that is guaranteed to
+  ///     identify some word boundary at or before `i`.
+  @available(SwiftStdlib 6.3, *)
+  public func _wordIndex(somewhereAtOrBefore i: Index) -> Index {
+    var j = _guts.validateInclusiveScalarIndex(i)
+    if j == endIndex {
+      return j
+    }
+    var recognizer = Unicode._RandomAccessWordRecognizer(
+      before: self.unicodeScalars[j])
+    var candidate = j
+    while j > self.startIndex {
+      let p = self.unicodeScalars.index(before: j)
+      let b = recognizer.hasGuaranteedBreak(after: self.unicodeScalars[p])
+      if b.setCandidate { candidate = j }
+      if b.breakAtCandidate { return candidate }
+      if b.breakHere { return j }
+      j = p
+    }
+    return j
+  }
 
-      // We were able to update previousRIIndex!
-      if count.isMultiple(of: 2) {
-        return previousRIIndex
+  /// Return the word boundary position following a known word boundary within
+  /// this string.
+  ///
+  /// This implements the word boundary specification of [Unicode Annex
+  /// #29](https://unicode.org/reports/tr29/#Default_Word_Boundaries). The
+  /// algorithm is not stable, and it allows implementers to tailor it to their
+  /// needs; accordingly, the result of this operation may vary between Unicode
+  /// implementations and system configurations, including versions of the Swift
+  /// Standard Library.
+  ///
+  /// Note: The input index must be on a known word boundary, otherwise the
+  /// result of this operation is unspecified. The start and end indices are
+  /// always known word boundaries, in every string.
+  ///
+  /// - Parameter i: A valid index addressing a word boundary within this
+  ///     string.
+  /// - Returns: The first word break strictly following `i` in the string.
+  @available(StdlibDeploymentTarget 5.7, *)
+  public func _wordIndex(after i: String.Index) -> String.Index {
+    guard #available(StdlibDeploymentTarget 6.3, *) else {
+      fatalError("Unreachable")
+    }
+    let i = _guts.validateScalarIndex(i)
+    if _slowPath(_guts.isForeign) {
+      return _guts._nextForeignWordIndex(after: i)
+    }
+    return _guts._nextUTF8WordIndex(after: i)
+  }
+}
+
+extension _StringGuts {
+  @available(StdlibDeploymentTarget 6.3, *)
+  @inline(never)
+  @_effects(releasenone)
+  internal func _nextUTF8WordIndex(after index: Index) -> Index {
+    _internalInvariant(self.isFastUTF8)
+    let result = unsafe self.withFastUTF8 { utf8 in
+      var offset = index._encodedOffset
+      let first = unsafe _decodeScalar(utf8, startingAt: offset)
+      offset &+= first.scalarLength
+      var recognizer = Unicode._WordRecognizer(after: first.0)
+      var candidate = offset
+      while offset < utf8.count {
+        let (scalar, len) = unsafe _decodeScalar(utf8, startingAt: offset)
+        let r = recognizer.hasBreak(before: scalar)
+        if r.setCandidate { candidate = offset }
+        if r.breakAtCandidate { return candidate }
+        if r.breakHere { return offset }
+        offset &+= len
+      }
+      if recognizer.hasCandidateBreakAtEnd() {
+        return candidate
       }
+      return offset
     }
+    // Note: We only signal that the result is scalar aligned, not
+    // character-aligned. Unicode does attempt to ensure that word breaks are
+    // always character-aligned, but this is not a strict guarantee, especially
+    // not if either segmentation algorithm has a tailored implementation. (As
+    // of 6.3, we do not tailor our implementations, but we used to do so and we
+    // may choose to do it again in the future.)
+    return Index(_encodedOffset: result)._scalarAligned._knownUTF8
+  }
 
-    return nil
+  @available(StdlibDeploymentTarget 6.3, *)
+  @inline(never)
+  internal func _nextForeignWordIndex(after index: Index) -> Index {
+    #if _runtime(_ObjC)
+    _internalInvariant(self.isForeign)
+    let scalars = String.UnicodeScalarView(self)
+    var recognizer = Unicode._WordRecognizer(after: scalars[index])
+    var i = scalars.index(after: index)
+    var candidate = i
+    while i < scalars.endIndex {
+      let r = recognizer.hasBreak(before: scalars[i])
+      if r.setCandidate { candidate = i }
+      if r.breakAtCandidate { return candidate }
+      if r.breakHere { return i }
+      scalars.formIndex(after: &i)
+    }
+    if recognizer.hasCandidateBreakAtEnd() {
+      return candidate
+    }
+    return i
+    #else
+    fatalError("Foreign strings are unsupported on this platform")
+    #endif
   }
 }
-
diff --git a/stdlib/public/core/Substring.swift b/stdlib/public/core/Substring.swift
index 845265c741f6c..e4e91b6a02a4c 100644
--- a/stdlib/public/core/Substring.swift
+++ b/stdlib/public/core/Substring.swift
@@ -749,8 +749,38 @@ extension Substring.UTF8View: BidirectionalCollection {
   }
 }
 
+@available(SwiftStdlib 6.2, *)
 extension Substring.UTF8View {
 
+  @lifetime(borrow self)
+  private borrowing func _underlyingSpan() -> Span<UTF8.CodeUnit> {
+#if _runtime(_ObjC)
+    // handle non-UTF8 Objective-C bridging cases here
+    if !_wholeGuts.isFastUTF8, _wholeGuts._object.hasObjCBridgeableObject {
+      let base: String.UTF8View = self._base
+      let first = base._foreignDistance(from: base.startIndex, to: startIndex)
+      let count = base._foreignDistance(from: startIndex, to: endIndex)
+      let span = base._underlyingSpan().extracting(first..<(first &+ count))
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+#endif // _runtime(_ObjC)
+    let first = _slice._startIndex._encodedOffset
+    let end = _slice._endIndex._encodedOffset
+    if _wholeGuts.isSmall {
+      let a = Builtin.addressOfBorrow(self)
+      let offset = first &+ (2 &* MemoryLayout<String.Index>.stride)
+      let start = unsafe UnsafePointer<UTF8.CodeUnit>(a).advanced(by: offset)
+      let span = unsafe Span(_unsafeStart: start, count: end &- first)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+    let isFastUTF8 = _wholeGuts.isFastUTF8
+    _precondition(isFastUTF8, "Substring must be contiguous UTF8")
+    var span = unsafe Span(_unsafeElements: _wholeGuts._object.fastUTF8)
+    span = span.extracting(first..<end)
+    return unsafe _overrideLifetime(span, borrowing: self)
+  }
+
+#if !(os(watchOS) && _pointerBitWidth(_32))
   /// A span over the UTF8 code units that make up this substring.
   ///
   /// - Note: In the case of bridged UTF16 String instances (on Apple
@@ -776,32 +806,80 @@ extension Substring.UTF8View {
   public var span: Span<UTF8.CodeUnit> {
     @lifetime(borrow self)
     borrowing get {
-#if _runtime(_ObjC)
-      // handle non-UTF8 Objective-C bridging cases here
-      if !_wholeGuts.isFastUTF8 && _wholeGuts._object.hasObjCBridgeableObject {
-        let base: String.UTF8View = self._base
-        let first = base._foreignDistance(from: base.startIndex, to: startIndex)
-        let count = base._foreignDistance(from: startIndex, to: endIndex)
-        let span = base.span._extracting(first..<(first &+ count))
-        return unsafe _overrideLifetime(span, borrowing: self)
-      }
-#endif
-      let first = _slice._startIndex._encodedOffset
-      let end = _slice._endIndex._encodedOffset
-      if _wholeGuts.isSmall {
-        fatalError("Span over the small string form is not supported yet.")
-//        let a = Builtin.addressOfBorrow(self)
-//        let offset = first &+ (2 &* MemoryLayout<String.Index>.stride)
-//        let start = unsafe UnsafePointer<UTF8.CodeUnit>(a).advanced(by: offset)
-//        let span = unsafe Span(_unsafeStart: start, count: end &- first)
-//        return unsafe _overrideLifetime(span, borrowing: self)
+      _underlyingSpan()
+    }
+  }
+
+  /// A span over the UTF8 code units that make up this substring.
+  ///
+  /// - Note: In the case of bridged UTF16 String instances (on Apple
+  /// platforms,) this property needs to transcode the code units every time
+  /// it is called.
+  /// For example, if `string` has the bridged UTF16 representation,
+  ///     for word in string.split(separator: " ") {
+  ///         useSpan(word.span)
+  ///     }
+  ///  is accidentally quadratic because of this issue. A workaround is to
+  ///  explicitly convert the string into its native UTF8 representation:
+  ///      var nativeString = consume string
+  ///      nativeString.makeContiguousUTF8()
+  ///      for word in nativeString.split(separator: " ") {
+  ///          useSpan(word.span)
+  ///      }
+  ///  This second option has linear time complexity, as expected.
+  ///
+  ///  Returns: a `Span` over the UTF8 code units of this Substring.
+  ///
+  ///  Complexity: O(1) for native UTF8 Strings, O(n) for bridged UTF16 Strings.
+  @available(SwiftStdlib 6.2, *)
+  public var _span: Span<UTF8.CodeUnit>? {
+    @_alwaysEmitIntoClient @inline(__always)
+    @lifetime(borrow self)
+    borrowing get {
+      span
+    }
+  }
+#else // !(os(watchOS) && _pointerBitWidth(_32))
+  @available(watchOS, unavailable)
+  public var span: Span<UTF8.CodeUnit> {
+    fatalError("\(#function) unavailable on 32-bit watchOS")
+  }
+
+  /// A span over the UTF8 code units that make up this substring.
+  ///
+  /// - Note: In the case of bridged UTF16 String instances (on Apple
+  /// platforms,) this property needs to transcode the code units every time
+  /// it is called.
+  /// For example, if `string` has the bridged UTF16 representation,
+  ///     for word in string.split(separator: " ") {
+  ///         useSpan(word.span)
+  ///     }
+  ///  is accidentally quadratic because of this issue. A workaround is to
+  ///  explicitly convert the string into its native UTF8 representation:
+  ///      var nativeString = consume string
+  ///      nativeString.makeContiguousUTF8()
+  ///      for word in nativeString.split(separator: " ") {
+  ///          useSpan(word.span)
+  ///      }
+  ///  This second option has linear time complexity, as expected.
+  ///
+  ///  Returns: a `Span` over the UTF8 code units of this Substring, or `nil`
+  ///           if the Substring does not have a contiguous representation.
+  ///
+  ///  Complexity: O(1) for native UTF8 Strings, O(n) for bridged UTF16 Strings.
+  @available(SwiftStdlib 6.2, *)
+  public var _span: Span<UTF8.CodeUnit>? {
+    @lifetime(borrow self)
+    borrowing get {
+      if _wholeGuts.isSmall,
+         _wholeGuts.count > _SmallString.contiguousCapacity() {
+        // substring is spannable only when the whole string is spannable.
+        return nil
       }
-      _internalInvariant(_wholeGuts.isFastUTF8)
-      var span = unsafe Span(_unsafeElements: _wholeGuts._object.fastUTF8)
-      span = span._extracting(first..<end)
-      return unsafe _overrideLifetime(span, borrowing: self)
+      return _underlyingSpan()
     }
   }
+#endif // !(os(watchOS) && _pointerBitWidth(_32))
 }
 
 extension Substring {
diff --git a/stdlib/public/core/SwiftNativeNSArray.swift b/stdlib/public/core/SwiftNativeNSArray.swift
index ffbc557cda7ce..13d097c31f209 100644
--- a/stdlib/public/core/SwiftNativeNSArray.swift
+++ b/stdlib/public/core/SwiftNativeNSArray.swift
@@ -53,6 +53,7 @@ internal class __SwiftNativeNSArrayWithContiguousStorage
   deinit {}
 
   // Operate on our contiguous storage
+  @_effects(releasenone)
   internal func withUnsafeBufferOfObjects<R>(
     _ body: (UnsafeBufferPointer<AnyObject>) throws -> R
   ) rethrows -> R {
@@ -379,6 +380,7 @@ extension __SwiftNativeNSArrayWithContiguousStorage {
     _destroyBridgedStorage(_heapBufferBridged)
   }
 
+  @_effects(releasenone)
   internal override func withUnsafeBufferOfObjects<R>(
     _ body: (UnsafeBufferPointer<AnyObject>) throws -> R
   ) rethrows -> R {
@@ -438,7 +440,8 @@ extension __SwiftNativeNSArrayWithContiguousStorage {
 internal final class __SwiftDeferredStaticNSArray<Element>
   : __SwiftDeferredNSArray {
 
-  internal override func withUnsafeBufferOfObjects<R>(
+  @_effects(releasenone)
+  final internal override func withUnsafeBufferOfObjects<R>(
     _ body: (UnsafeBufferPointer<AnyObject>) throws -> R
   ) rethrows -> R {
     while true {
@@ -526,6 +529,7 @@ internal class __ContiguousArrayStorageBase
   }
   
 #if _runtime(_ObjC)
+  @_effects(releasenone)
   internal override func withUnsafeBufferOfObjects<R>(
     _ body: (UnsafeBufferPointer<AnyObject>) throws -> R
   ) rethrows -> R {
diff --git a/stdlib/public/core/SwiftSettings.swift b/stdlib/public/core/SwiftSettings.swift
deleted file mode 100644
index 5db14ec144a0a..0000000000000
--- a/stdlib/public/core/SwiftSettings.swift
+++ /dev/null
@@ -1,27 +0,0 @@
-//===--- SwiftSettings.swift ----------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-#if $Macros
-
-@available(SwiftStdlib 9999, *)
-public struct SwiftSetting {
-  public init() {
-    fatalError("A SwiftSetting should never actually be constructed")
-  }
-}
-
-@available(SwiftStdlib 9999, *)
-@freestanding(declaration)
-public macro SwiftSettings(_ settings: SwiftSetting...) =
-  Builtin.SwiftSettingsMacro
-
-#endif
diff --git a/stdlib/public/core/SwiftifyImport.swift b/stdlib/public/core/SwiftifyImport.swift
index 3efd0a645098a..1641ef8002bca 100644
--- a/stdlib/public/core/SwiftifyImport.swift
+++ b/stdlib/public/core/SwiftifyImport.swift
@@ -54,12 +54,54 @@ public enum _SwiftifyInfo {
 /// It will replace some std::span arguments with Swift's Span type when sufficient information is
 /// available.
 ///
-/// Currently not supported: return pointers, nested pointers, pointee "count" parameters, endedBy.
+/// Currently not supported: nested pointers, pointee "count" parameters, endedBy.
 ///
 /// Parameter paramInfo: information about how the function uses the pointer passed to it. The
 /// safety of the generated wrapper function depends on this info being extensive and accurate.
 #if hasFeature(Macros)
 @attached(peer, names: overloaded)
-public macro _SwiftifyImport(_ paramInfo: _SwiftifyInfo..., typeMappings: [String: String] = [:]) =
+public macro _SwiftifyImport(_ paramInfo: _SwiftifyInfo...,
+                             spanAvailability: String? = nil,
+                             typeMappings: [String: String] = [:]) =
     #externalMacro(module: "SwiftMacros", type: "SwiftifyImportMacro")
 #endif
+
+/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
+/// a value identical to `dependent` with a lifetime dependency on the caller's
+/// borrow scope of the `source` argument.
+///
+/// This mimics the stdlib definition. It is public for use with import macros.
+@unsafe
+@_unsafeNonescapableResult
+@_alwaysEmitIntoClient
+@_transparent
+@lifetime(borrow source)
+public func _swiftifyOverrideLifetime<
+  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
+>(
+  _ dependent: consuming T, borrowing source: borrowing U
+) -> T {
+  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
+  // should be expressed by a builtin that is hidden within the function body.
+  dependent
+}
+
+/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
+/// a value identical to `dependent` that inherits all lifetime dependencies from
+/// the `source` argument.
+///
+/// This mimics the stdlib definition. It is public for use with import macros.
+@unsafe
+@_unsafeNonescapableResult
+@_alwaysEmitIntoClient
+@_transparent
+@lifetime(copy source)
+public func _swiftifyOverrideLifetime<
+  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
+>(
+  _ dependent: consuming T, copying source: borrowing U
+) -> T {
+  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
+  // should be expressed by a builtin that is hidden within the function body.
+  dependent
+}
diff --git a/stdlib/public/core/TemporaryAllocation.swift b/stdlib/public/core/TemporaryAllocation.swift
index fa2cf2df2d217..960eec28492f6 100644
--- a/stdlib/public/core/TemporaryAllocation.swift
+++ b/stdlib/public/core/TemporaryAllocation.swift
@@ -119,8 +119,6 @@ internal func _isStackAllocationSafe(byteCount: Int, alignment: Int) -> Bool {
 ///
 /// - Returns: Whatever is returned by `body`.
 ///
-/// - Throws: Whatever is thrown by `body`.
-///
 /// This function encapsulates the various calls to builtins required by
 /// `withUnsafeTemporaryAllocation()`.
 @_alwaysEmitIntoClient @_transparent
@@ -130,13 +128,13 @@ internal func _withUnsafeTemporaryAllocation<
   of type: T.Type,
   capacity: Int,
   alignment: Int,
-  _ body: (Builtin.RawPointer) throws -> R
-) rethrows -> R {
+  _ body: (Builtin.RawPointer) -> R
+) -> R {
   // How many bytes do we need to allocate?
   let byteCount = _byteCountForTemporaryAllocation(of: type, capacity: capacity)
 
   guard _isStackAllocationSafe(byteCount: byteCount, alignment: alignment) else {
-    return try _fallBackToHeapAllocation(byteCount: byteCount, alignment: alignment, body)
+    return _fallBackToHeapAllocation(byteCount: byteCount, alignment: alignment, body)
   }
 
   // This declaration must come BEFORE Builtin.stackAlloc() or
@@ -154,15 +152,9 @@ internal func _withUnsafeTemporaryAllocation<
   // The multiple calls to Builtin.stackDealloc() are because defer { } produces
   // a child function at the SIL layer and that conflicts with the verifier's
   // idea of a stack allocation's lifetime.
-  do {
-    result = try body(stackAddress)
-    Builtin.stackDealloc(stackAddress)
-    return result
-
-  } catch {
-    Builtin.stackDealloc(stackAddress)
-    throw error
-  }
+  result = body(stackAddress)
+  Builtin.stackDealloc(stackAddress)
+  return result
 #else
   fatalError("unsupported compiler")
 #endif
@@ -175,13 +167,13 @@ internal func _withUnprotectedUnsafeTemporaryAllocation<
   of type: T.Type,
   capacity: Int,
   alignment: Int,
-  _ body: (Builtin.RawPointer) throws -> R
-) rethrows -> R {
+  _ body: (Builtin.RawPointer) -> R
+) -> R {
   // How many bytes do we need to allocate?
   let byteCount = _byteCountForTemporaryAllocation(of: type, capacity: capacity)
 
   guard _isStackAllocationSafe(byteCount: byteCount, alignment: alignment) else {
-    return try _fallBackToHeapAllocation(byteCount: byteCount, alignment: alignment, body)
+    return _fallBackToHeapAllocation(byteCount: byteCount, alignment: alignment, body)
   }
 
   // This declaration must come BEFORE Builtin.unprotectedStackAlloc() or
@@ -198,23 +190,17 @@ internal func _withUnprotectedUnsafeTemporaryAllocation<
   // The multiple calls to Builtin.stackDealloc() are because defer { } produces
   // a child function at the SIL layer and that conflicts with the verifier's
   // idea of a stack allocation's lifetime.
-  do {
-    result = try body(stackAddress)
-    Builtin.stackDealloc(stackAddress)
-    return result
-
-  } catch {
-    Builtin.stackDealloc(stackAddress)
-    throw error
-  }
+  result = body(stackAddress)
+  Builtin.stackDealloc(stackAddress)
+  return result
 }
 
 @_alwaysEmitIntoClient @_transparent
-internal func _fallBackToHeapAllocation<R: ~Copyable>(
+internal func _fallBackToHeapAllocation<R: ~Copyable, E: Error>(
   byteCount: Int,
   alignment: Int,
-  _ body: (Builtin.RawPointer) throws -> R
-) rethrows -> R {
+  _ body: (Builtin.RawPointer) throws(E) -> R
+) throws(E) -> R {
   let buffer = UnsafeMutableRawPointer.allocate(
     byteCount: byteCount,
     alignment: alignment
@@ -259,22 +245,28 @@ internal func _fallBackToHeapAllocation<R: ~Copyable>(
 /// the buffer) must not escape. It will be deallocated when `body` returns and
 /// cannot be used afterward.
 @_alwaysEmitIntoClient @_transparent
-public func withUnsafeTemporaryAllocation<R: ~Copyable>(
+public func withUnsafeTemporaryAllocation<R: ~Copyable, E: Error>(
   byteCount: Int,
   alignment: Int,
-  _ body: (UnsafeMutableRawBufferPointer) throws -> R
-) rethrows -> R {
-  return try _withUnsafeTemporaryAllocation(
+  _ body: (UnsafeMutableRawBufferPointer) throws(E) -> R
+) throws(E) -> R {
+  let result: Result<R, E> = _withUnsafeTemporaryAllocation(
     of: Int8.self,
     capacity: byteCount,
     alignment: alignment
   ) { pointer in
-    let buffer = unsafe UnsafeMutableRawBufferPointer(
-      start: .init(pointer),
-      count: byteCount
-    )
-    return try unsafe body(buffer)
+    do throws(E) {
+      let buffer = unsafe UnsafeMutableRawBufferPointer(
+        start: .init(pointer),
+        count: byteCount
+      )
+      return .success(try unsafe body(buffer))
+    } catch {
+      return .failure(error)
+    }
   }
+
+  return try result.get()
 }
 
 /// Provides scoped access to a raw buffer pointer with the specified byte count
@@ -283,22 +275,28 @@ public func withUnsafeTemporaryAllocation<R: ~Copyable>(
 /// This function is similar to `withUnsafeTemporaryAllocation`, except that it
 /// doesn't trigger stack protection for the stack allocated memory.
 @_alwaysEmitIntoClient @_transparent
-public func _withUnprotectedUnsafeTemporaryAllocation<R: ~Copyable>(
+public func _withUnprotectedUnsafeTemporaryAllocation<R: ~Copyable, E: Error>(
   byteCount: Int,
   alignment: Int,
-  _ body: (UnsafeMutableRawBufferPointer) throws -> R
-) rethrows -> R {
-  return try _withUnprotectedUnsafeTemporaryAllocation(
+  _ body: (UnsafeMutableRawBufferPointer) throws(E) -> R
+) throws(E) -> R {
+  let result: Result<R, E> = _withUnprotectedUnsafeTemporaryAllocation(
     of: Int8.self,
     capacity: byteCount,
     alignment: alignment
   ) { pointer in
-    let buffer = unsafe UnsafeMutableRawBufferPointer(
-      start: .init(pointer),
-      count: byteCount
-    )
-    return try unsafe body(buffer)
+    do throws(E) {
+      let buffer = unsafe UnsafeMutableRawBufferPointer(
+        start: .init(pointer),
+        count: byteCount
+      )
+      return try unsafe .success(body(buffer))
+    } catch {
+      return .failure(error)
+    }
   }
+
+  return try result.get()
 }
 
 /// Provides scoped access to a buffer pointer to memory of the specified type
@@ -334,24 +332,31 @@ public func _withUnprotectedUnsafeTemporaryAllocation<R: ~Copyable>(
 /// cannot be used afterward.
 @_alwaysEmitIntoClient @_transparent
 public func withUnsafeTemporaryAllocation<
-  T: ~Copyable,R: ~Copyable
+  T: ~Copyable,R: ~Copyable,
+  E: Error
 >(
   of type: T.Type,
   capacity: Int,
-  _ body: (UnsafeMutableBufferPointer<T>) throws -> R
-) rethrows -> R {
-  return try _withUnsafeTemporaryAllocation(
+  _ body: (UnsafeMutableBufferPointer<T>) throws(E) -> R
+) throws(E) -> R {
+  let result: Result<R, E> = _withUnsafeTemporaryAllocation(
     of: type,
     capacity: capacity,
     alignment: MemoryLayout<T>.alignment
   ) { pointer in
-    Builtin.bindMemory(pointer, capacity._builtinWordValue, type)
-    let buffer = unsafe UnsafeMutableBufferPointer<T>(
-      start: .init(pointer),
-      count: capacity
-    )
-    return try unsafe body(buffer)
+    do throws(E) {
+      Builtin.bindMemory(pointer, capacity._builtinWordValue, type)
+      let buffer = unsafe UnsafeMutableBufferPointer<T>(
+        start: .init(pointer),
+        count: capacity
+      )
+      return try unsafe .success(body(buffer))
+    } catch {
+      return .failure(error)
+    }
   }
+
+  return try result.get()
 }
 
 /// Provides scoped access to a buffer pointer to memory of the specified type
@@ -361,22 +366,29 @@ public func withUnsafeTemporaryAllocation<
 /// doesn't trigger stack protection for the stack allocated memory.
 @_alwaysEmitIntoClient @_transparent
 public func _withUnprotectedUnsafeTemporaryAllocation<
-  T: ~Copyable, R: ~Copyable
+  T: ~Copyable, R: ~Copyable,
+  E: Error
 >(
   of type: T.Type,
   capacity: Int,
-  _ body: (UnsafeMutableBufferPointer<T>) throws -> R
-) rethrows -> R {
-  return try _withUnprotectedUnsafeTemporaryAllocation(
+  _ body: (UnsafeMutableBufferPointer<T>) throws(E) -> R
+) throws(E) -> R {
+  let result: Result<R, E> = _withUnprotectedUnsafeTemporaryAllocation(
     of: type,
     capacity: capacity,
     alignment: MemoryLayout<T>.alignment
   ) { pointer in
-    Builtin.bindMemory(pointer, capacity._builtinWordValue, type)
-    let buffer = unsafe UnsafeMutableBufferPointer<T>(
-      start: .init(pointer),
-      count: capacity
-    )
-    return try unsafe body(buffer)
+    do throws(E) {
+      Builtin.bindMemory(pointer, capacity._builtinWordValue, type)
+      let buffer = unsafe UnsafeMutableBufferPointer<T>(
+        start: .init(pointer),
+        count: capacity
+      )
+      return try unsafe .success(body(buffer))
+    } catch {
+      return .failure(error)
+    }
   }
+
+  return try result.get()
 }
diff --git a/stdlib/public/core/UInt128.swift b/stdlib/public/core/UInt128.swift
index 3e222daf60b05..47c5d7c79d713 100644
--- a/stdlib/public/core/UInt128.swift
+++ b/stdlib/public/core/UInt128.swift
@@ -47,7 +47,7 @@ public struct UInt128: Sendable {
 #if _endian(little)
     self = unsafe unsafeBitCast((_low, _high), to: Self.self)
 #else
-    self = unsafeBitCast((_high, _low), to: Self.self)
+    self = unsafe unsafeBitCast((_high, _low), to: Self.self)
 #endif
   }
   
@@ -76,7 +76,7 @@ public struct UInt128: Sendable {
   public var _value: Builtin.Int128 {
     @_transparent
     get {
-      unsafeBitCast(self, to: Builtin.Int128.self)
+      unsafe unsafeBitCast(self, to: Builtin.Int128.self)
     }
 
     @_transparent
@@ -88,7 +88,7 @@ public struct UInt128: Sendable {
   @available(SwiftStdlib 6.0, *)
   @_transparent
   public init(_ _value: Builtin.Int128) {
-    self = unsafeBitCast(_value, to: Self.self)
+    self = unsafe unsafeBitCast(_value, to: Self.self)
   }
 #endif
 
diff --git a/stdlib/public/core/UTF8EncodingError.swift b/stdlib/public/core/UTF8EncodingError.swift
new file mode 100644
index 0000000000000..80ea1885ee679
--- /dev/null
+++ b/stdlib/public/core/UTF8EncodingError.swift
@@ -0,0 +1,264 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+extension Unicode.UTF8 {
+  /**
+
+   The kind and location of a UTF-8 encoding error.
+
+   Valid UTF-8 is represented by this table:
+
+   | Scalar value       | Byte 0 | Byte 1 | Byte 2 | Byte 3 |
+   | ------------------ | ------ | ------ | ------ | ------ |
+   | U+0000..U+007F     | 00..7F |        |        |        |
+   | U+0080..U+07FF     | C2..DF | 80..BF |        |        |
+   | U+0800..U+0FFF     | E0     | A0..BF | 80..BF |        |
+   | U+1000..U+CFFF     | E1..EC | 80..BF | 80..BF |        |
+   | U+D000..U+D7FF     | ED     | 80..9F | 80..BF |        |
+   | U+E000..U+FFFF     | EE..EF | 80..BF | 80..BF |        |
+   | U+10000..U+3FFFF   | F0     | 90..BF | 80..BF | 80..BF |
+   | U+40000..U+FFFFF   | F1..F3 | 80..BF | 80..BF | 80..BF |
+   | U+100000..U+10FFFF | F4     | 80..8F | 80..BF | 80..BF |
+
+   ### Classifying errors
+
+   An *unexpected continuation* is when a continuation byte (`10xxxxxx`) occurs
+   in a position that should be the start of a new scalar value. Unexpected
+   continuations can often occur when the input contains arbitrary data
+   instead of textual content. An unexpected continuation at the start of
+   input might mean that the input was not correctly sliced along scalar
+   boundaries or that it does not contain UTF-8.
+
+   A *truncated scalar* is a multi-byte sequence that is the start of a valid
+   multi-byte scalar but is cut off before ending correctly. A truncated
+   scalar at the end of the input might mean that only part of the entire
+   input was received.
+
+   A *surrogate code point* (`U+D800..U+DFFF`) is invalid UTF-8. Surrogate
+   code points are used by UTF-16 to encode scalars in the supplementary
+   planes. Their presence may mean the input was encoded in a different 8-bit
+   encoding, such as CESU-8, WTF-8, or Java's Modified UTF-8.
+
+   An *invalid non-surrogate code point* is any code point higher than
+   `U+10FFFF`. This can often occur when the input is arbitrary data instead
+   of textual content.
+
+   An *overlong encoding* occurs when a scalar value that could have been
+   encoded using fewer bytes is encoded in a longer byte sequence. Overlong
+   encodings are invalid UTF-8 and can lead to security issues if not
+   correctly detected:
+
+   - <https://nvd.nist.gov/vuln/detail/CVE-2008-2938>
+   - <https://nvd.nist.gov/vuln/detail/CVE-2000-0884>
+
+   An overlong encoding of `NUL`, `0xC0 0x80`, is used in Java's Modified
+   UTF-8 but is invalid UTF-8. Overlong encoding errors often catch attempts
+   to bypass security measures.
+
+   ### Reporting the range of the error
+
+   The range of the error reported follows the *Maximal subpart of an
+   ill-formed subsequence* algorithm in which each error is either one byte
+   long or ends before the first byte that is disallowed. See "U+FFFD
+   Substitution of Maximal Subparts" in the Unicode Standard. Unicode started
+   recommending this algorithm in version 6 and is adopted by the W3C.
+
+   The maximal subpart algorithm will produce a single multi-byte range for a
+   truncated scalar (a multi-byte sequence that is the start of a valid
+   multi-byte scalar but is cut off before ending correctly). For all other
+   errors (including overlong encodings, surrogates, and invalid code
+   points), it will produce an error per byte.
+
+   Since overlong encodings, surrogates, and invalid code points are erroneous
+   by the second byte (at the latest), the above definition produces the same
+   ranges as defining such a sequence as a truncated scalar error followed by
+   unexpected continuation byte errors. The more semantically-rich
+   classification is reported.
+
+   For example, a surrogate count point sequence `ED A0 80` will be reported
+   as three `.surrogateCodePointByte` errors rather than a `.truncatedScalar`
+   followed by two `.unexpectedContinuationByte` errors.
+
+   Other commonly reported error ranges can be constructed from this result.
+   For example, PEP 383's error-per-byte can be constructed by mapping over
+   the reported range. Similarly, constructing a single error for the longest
+   invalid byte range can be constructed by joining adjacent error ranges.
+
+   | Algorithm       | 61   | F1  | 80  | 80  | E1  | 80  | C2  | 62   |
+   | --------------- | ---- | --- | --- | --- | --- | --- | --- | ---- |
+   | Longest range   | U+61 | err |     |     |     |     |     | U+62 |
+   | Maximal subpart | U+61 | err |     |     | err |     | err | U+62 |
+   | Error per byte  | U+61 | err | err | err | err | err | err | U+62 |
+
+   */
+  @available(SwiftStdlib 6.2, *)
+  @frozen
+  public struct ValidationError: Error, Sendable, Hashable
+  {
+    /// The kind of encoding error
+    public var kind: Unicode.UTF8.ValidationError.Kind
+
+    /// The range of offsets into our input containing the error
+    public var byteOffsets: Range<Int>
+
+    @_alwaysEmitIntoClient
+    public init(
+      _ kind: Unicode.UTF8.ValidationError.Kind,
+      _ byteOffsets: Range<Int>
+    ) {
+      _precondition(byteOffsets.lowerBound >= 0)
+      if kind == .truncatedScalar {
+        _precondition(!byteOffsets.isEmpty)
+        _precondition(byteOffsets.count < 4)
+      } else {
+        _precondition(byteOffsets.count == 1)
+      }
+
+      self.kind = kind
+      self.byteOffsets = byteOffsets
+    }
+
+    @_alwaysEmitIntoClient
+    public init(
+      _ kind: Unicode.UTF8.ValidationError.Kind, at byteOffset: Int
+    ) {
+      self.init(kind, byteOffset..<(byteOffset+1))
+    }
+  }
+}
+
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8.ValidationError {
+  /// The kind of encoding error encountered during validation
+  @frozen
+  public struct Kind: Error, Sendable, Hashable, RawRepresentable
+   {
+    public var rawValue: UInt8
+
+    @inlinable
+    public init?(rawValue: UInt8) {
+      guard rawValue <= 4 else { return nil }
+      self.rawValue = rawValue
+    }
+
+    /// A continuation byte (`10xxxxxx`) outside of a multi-byte sequence
+    @_alwaysEmitIntoClient
+    public static var unexpectedContinuationByte: Self {
+      .init(rawValue: 0)!
+    }
+
+    /// A byte in a surrogate code point (`U+D800..U+DFFF`) sequence
+    @_alwaysEmitIntoClient
+    public static var surrogateCodePointByte: Self {
+      .init(rawValue: 1)!
+    }
+
+    /// A byte in an invalid, non-surrogate code point (`>U+10FFFF`) sequence
+    @_alwaysEmitIntoClient
+    public static var invalidNonSurrogateCodePointByte: Self {
+      .init(rawValue: 2)!
+    }
+
+    /// A byte in an overlong encoding sequence
+    @_alwaysEmitIntoClient
+    public static var overlongEncodingByte: Self {
+      .init(rawValue: 3)!
+    }
+
+    /// A multi-byte sequence that is the start of a valid multi-byte scalar
+    /// but is cut off before ending correctly
+    @_alwaysEmitIntoClient
+    public static var truncatedScalar: Self {
+      .init(rawValue: 4)!
+    }
+  }
+}
+
+@_unavailableInEmbedded
+@available(SwiftStdlib 6.2, *)
+extension UTF8.ValidationError.Kind: CustomStringConvertible {
+  public var description: String {
+    switch self {
+    case .invalidNonSurrogateCodePointByte:
+      ".invalidNonSurrogateCodePointByte"
+    case .overlongEncodingByte:
+      ".overlongEncodingByte"
+    case .surrogateCodePointByte:
+      ".surrogateCodePointByte"
+    case .truncatedScalar:
+      ".truncatedScalar"
+    case .unexpectedContinuationByte:
+      ".unexpectedContinuationByte"
+    default:
+      fatalError("unreachable")
+    }
+  }
+}
+
+@_unavailableInEmbedded
+@available(SwiftStdlib 6.2, *)
+extension UTF8.ValidationError: CustomStringConvertible {
+  public var description: String {
+    "UTF8.ValidationError(\(kind), \(byteOffsets))"
+  }
+}
+
+extension UTF8 {
+  @available(SwiftStdlib 6.2, *)
+  @usableFromInline // for testing purposes
+  internal static func _checkAllErrors(
+    _ s: some Sequence<UInt8>
+  ) -> Array<UTF8.ValidationError> {
+    // TODO: Span fast path
+    // TODO: Fixed size buffer for non-contig inputs
+    // TODO: Lifetime-dependent result variant
+    let cus = Array(s)
+    return unsafe cus.withUnsafeBytes {
+      var bufPtr = unsafe $0
+      var start = 0
+      var errors: Array<UTF8.ValidationError> = []
+
+      // Remember the previous error, so that we can
+      // apply it to subsequent bytes instead of reporting
+      // just `.unexpectedContinuation`.
+      var priorError: UTF8.ValidationError? = nil
+      while true {
+        do throws(UTF8.ValidationError) {
+          _ = unsafe try bufPtr.baseAddress!._validateUTF8(limitedBy: bufPtr.count)
+          return errors
+        } catch {
+          let adjustedRange =
+            error.byteOffsets.lowerBound + start ..< error.byteOffsets.upperBound + start
+
+          let kind: UTF8.ValidationError.Kind
+          if let prior = priorError,
+             prior.byteOffsets.upperBound == adjustedRange.lowerBound,
+             error.kind == .unexpectedContinuationByte
+          {
+            kind = prior.kind
+          } else {
+            kind = error.kind
+          }
+          let adjustedErr = UTF8.ValidationError(kind, adjustedRange)
+          priorError = adjustedErr
+
+          let errEnd = error.byteOffsets.upperBound
+          start += errEnd
+          unsafe bufPtr = .init(rebasing: bufPtr[errEnd...])
+          errors.append(adjustedErr)
+        }
+      }
+      fatalError()
+    }
+  }
+}
diff --git a/stdlib/public/core/UTF8Span.swift b/stdlib/public/core/UTF8Span.swift
new file mode 100644
index 0000000000000..ebecccd52edd8
--- /dev/null
+++ b/stdlib/public/core/UTF8Span.swift
@@ -0,0 +1,484 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+/// A borrowed view into contiguous memory that contains validly-encoded UTF-8
+/// code units.
+@frozen
+@safe
+@available(SwiftStdlib 6.2, *)
+public struct UTF8Span: Copyable, ~Escapable, BitwiseCopyable {
+  @usableFromInline
+  internal var _unsafeBaseAddress: UnsafeRawPointer?
+
+  /*
+   A bit-packed count and flags (such as isASCII)
+
+   ╔═══════╦═════╦══════════╦═══════╗
+   ║  b63  ║ b62 ║ b61:56   ║ b55:0 ║
+   ╠═══════╬═════╬══════════╬═══════╣
+   ║ ASCII ║ NFC ║ reserved ║ count ║
+   ╚═══════╩═════╩══════════╩═══════╝
+
+   ASCII means the contents are known to be all-ASCII (<=0x7F).
+   NFC means contents are known to be in normal form C for fast comparisons.
+   */
+  @usableFromInline
+  internal var _countAndFlags: UInt64
+
+  // @_alwaysEmitIntoClient
+  @inline(__always)
+  @lifetime(borrow start)
+  internal init(
+    _unsafeAssumingValidUTF8 start: borrowing UnsafeRawPointer,
+    _countAndFlags: UInt64
+  ) {
+    unsafe self._unsafeBaseAddress = copy start
+    self._countAndFlags = _countAndFlags
+
+    _invariantCheck()
+  }
+
+  /// Creates a UTF8Span, bypassing safety and security checks. The caller
+  /// must guarantee that `codeUnits` contains validly-encoded UTF-8, or else
+  /// undefined behavior may result upon use. If `isKnownASCII: true is
+  /// passed`, the contents must be ASCII, or else undefined behavior may
+  /// result upon use.
+  @unsafe
+  @lifetime(copy codeUnits)
+  public init(
+    unchecked codeUnits: Span<UInt8>,
+    isKnownASCII: Bool = false
+  ) {
+    self.init(
+      _uncheckedAssumingValidUTF8: codeUnits,
+      isKnownASCII: isKnownASCII,
+      isKnownNFC: false
+    )
+  }
+
+  // FIXME: we need to make sure ALL API are nil safe, that is they
+  // at least check the count first
+  @_alwaysEmitIntoClient
+  internal func _start() -> UnsafeRawPointer {
+    unsafe _unsafeBaseAddress._unsafelyUnwrappedUnchecked
+  }
+}
+
+// TODO: try to convert code to be ran on Span instead of URP
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Creates a UTF8Span containing `codeUnits`. Validates that the input is
+  /// valid UTF-8, otherwise throws an error.
+  ///
+  /// The resulting UTF8Span has the same lifetime constraints as `codeUnits`.
+  ///
+  /// - Complexity: O(n)
+  @lifetime(copy codeUnits)
+  public init(
+    validating codeUnits: consuming Span<UInt8>
+  ) throws(UTF8.ValidationError) {
+    try self.init(_validating: codeUnits)
+  }
+
+  // TODO: this doesn't need to be underscored, I don't think
+  @lifetime(copy codeUnits)
+  internal init(
+    _validating codeUnits: consuming Span<UInt8>
+  ) throws(UTF8.ValidationError) {
+    guard let basePtr = unsafe codeUnits._pointer else {
+      unsafe self._unsafeBaseAddress = nil
+      self._countAndFlags = 0
+      return
+    }
+
+    let count = codeUnits._count
+    let isASCII = unsafe try basePtr._validateUTF8(limitedBy: count)
+
+    unsafe self._unsafeBaseAddress = .init(basePtr)
+    self._countAndFlags = UInt64(truncatingIfNeeded: count)
+    if isASCII {
+      _setIsASCII()
+    }
+    _internalInvariant(self.count == codeUnits.count)
+  }
+
+  // TODO: SPI?
+  @lifetime(copy codeUnits)
+  internal init(
+    _uncheckedAssumingValidUTF8 codeUnits: consuming Span<UInt8>,
+    isKnownASCII: Bool,
+    isKnownNFC: Bool
+  ) {
+    guard let ptr = unsafe codeUnits._pointer else {
+      unsafe self._unsafeBaseAddress = nil
+      self._countAndFlags = 0
+      return
+    }
+
+    unsafe self._unsafeBaseAddress = ptr
+    self._countAndFlags = UInt64(truncatingIfNeeded: codeUnits.count)
+    if isKnownASCII {
+      _setIsASCII()
+    }
+    if isKnownNFC {
+      _setIsNFC()
+    }
+    _internalInvariant(self.count == codeUnits.count)
+  }
+
+  // HACK: working around lack of internal plumbing work
+  internal var _str: String { unsafe _start()._str(0..<count) }
+}
+
+
+// MARK: String
+
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Calls a closure with a pointer to the viewed contiguous storage.
+  ///
+  /// The buffer pointer passed as an argument to `body` is valid only
+  /// during the execution of `withUnsafeBufferPointer(_:)`.
+  /// Do not store or return the pointer for later use.
+  ///
+  /// - Parameter body: A closure with an `UnsafeBufferPointer` parameter
+  ///   that points to the viewed contiguous storage. If `body` has
+  ///   a return value, that value is also used as the return value
+  ///   for the `withUnsafeBufferPointer(_:)` method. The closure's
+  ///   parameter is valid only for the duration of its execution.
+  /// - Returns: The return value of the `body` closure parameter.
+  @_alwaysEmitIntoClient
+  borrowing public func _withUnsafeBufferPointer<
+    E: Error, Result: ~Copyable //& ~Escapable
+  >(
+    _ body: (_ buffer: /*borrowing*/ UnsafeBufferPointer<UInt8>) throws(E) -> Result
+  ) throws(E) -> Result {
+    try unsafe body(_start()._ubp(0..<count))
+  }
+
+  // TODO: withSpan or similar?
+}
+
+// MARK: Internals
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+#if !INTERNAL_CHECKS_ENABLED
+  @inline(__always) internal func _invariantCheck() {}
+#else
+  @inline(never) @_effects(releasenone)
+  internal func _invariantCheck() {
+    // TODO: validate the UTF-8 as an assertion (and isASCII)
+  }
+#endif
+}
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// A Boolean value that indicates whether the UTF-8 span is empty.
+  ///
+  /// - Complexity: O(1)
+  public var isEmpty: Bool {
+    self.count == 0
+  }
+
+  /// A span used to access the code units.
+  ///
+  /// - Complexity: O(1)
+  public var span: Span<UInt8> {
+    @lifetime(copy self)
+    get {
+      let newSpan = unsafe Span<UInt8>(_unchecked: _unsafeBaseAddress, count: self.count)
+      return unsafe _overrideLifetime(newSpan, copying: self)
+    }
+  }
+
+
+}
+
+extension String {
+  /// Creates a new string, copying the specified code units.
+  ///
+  /// This initializer skips UTF-8 validation because `codeUnits` must contain
+  /// valid UTF-8.
+  ///
+  /// - Complexity: O(n)
+  @available(SwiftStdlib 6.2, *)
+  public init(copying codeUnits: UTF8Span) {
+    let isASCII = codeUnits.isKnownASCII
+    self = unsafe codeUnits._withUnsafeBufferPointer { bufPtr in
+      unsafe String._uncheckedFromUTF8(bufPtr, isASCII: isASCII)
+    }
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+extension String {
+
+  @lifetime(borrow self)
+  private borrowing func _underlyingSpan() -> Span<UTF8.CodeUnit> {
+#if _runtime(_ObjC)
+    // handle non-UTF8 Objective-C bridging cases here
+    if !_guts.isFastUTF8, _guts._object.hasObjCBridgeableObject {
+      let storage = _guts._getOrAllocateAssociatedStorage()
+      let (start, count) = unsafe (storage.start, storage.count)
+      let span = unsafe Span(_unsafeStart: start, count: count)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+#endif // _runtime(_ObjC)
+    let count = _guts.count
+    if _guts.isSmall {
+      let a = Builtin.addressOfBorrow(self)
+      let address = unsafe UnsafePointer<UTF8.CodeUnit>(a)
+      let span = unsafe Span(_unsafeStart: address, count: count)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+    let isFastUTF8 = _guts.isFastUTF8
+    _precondition(isFastUTF8, "String must be contiguous UTF8")
+    let buffer = unsafe _guts._object.fastUTF8
+    let span = unsafe Span(_unsafeElements: buffer)
+    return unsafe _overrideLifetime(span, borrowing: self)
+  }
+
+#if !(os(watchOS) && _pointerBitWidth(_32))
+  /// A UTF-8 span over the code units that make up this string.
+  ///
+  /// - Note: In the case of bridged UTF-16 string instances (on Apple
+  ///   platforms) this property transcodes the code units the first time
+  ///   it's called. The transcoded buffer is cached, and subsequent calls
+  ///   can reuse the buffer.
+  ///
+  /// - Returns: A `UTF8Span` over the code units of this string.
+  ///
+  /// - Complexity: O(1) for native UTF-8 strings, amortized O(1) for bridged
+  ///   UTF-16 strings.
+  @available(SwiftStdlib 6.2, *)
+  public var utf8Span: UTF8Span {
+    @lifetime(borrow self)
+    borrowing get {
+      unsafe UTF8Span(
+        unchecked: _underlyingSpan(), isKnownASCII: _guts.isASCII
+      )
+    }
+  }
+
+  /// A UTF-8 span over the code units that make up this string.
+  ///
+  /// - Note: In the case of bridged UTF-16 string instances (on Apple
+  ///   platforms) this property transcodes the code units the first time
+  ///   it's called. The transcoded buffer is cached, and subsequent calls
+  ///   can reuse the buffer.
+  ///
+  /// - Returns: A `UTF8Span` over the code units of this string.
+  ///
+  /// - Complexity: O(1) for native UTF-8 strings, amortized O(1) for bridged
+  ///   UTF-16 strings.
+  @available(SwiftStdlib 6.2, *)
+  public var _utf8Span: UTF8Span? {
+    @_alwaysEmitIntoClient @inline(__always)
+    @lifetime(borrow self)
+    borrowing get {
+      utf8Span
+    }
+  }
+#else // !(os(watchOS) && _pointerBitWidth(_32))
+  @available(watchOS, unavailable)
+  public var utf8Span: UTF8Span {
+    fatalError("\(#function) unavailable on 32-bit watchOS")
+  }
+
+  /// A UTF-8 span over the code units that make up this string.
+  ///
+  /// - Note: In the case of bridged UTF-16 string instances (on Apple
+  ///   platforms) this property transcodes the code units the first time
+  ///   it's called. The transcoded buffer is cached, and subsequent calls
+  ///   can reuse the buffer.
+  ///
+  /// - Returns: A `UTF8Span` over the code units of this string, or `nil`
+  ///   if the string does not have a contiguous representation.
+  ///
+  /// - Complexity: O(1) for native UTF-8 strings, amortized O(1) for bridged
+  ///   UTF-16 strings.
+  @available(SwiftStdlib 6.2, *)
+  public var _utf8Span: UTF8Span? {
+    @lifetime(borrow self)
+    borrowing get {
+      if _guts.isSmall, _guts.count > _SmallString.contiguousCapacity() {
+        return nil
+      }
+      return unsafe UTF8Span(
+        unchecked: _underlyingSpan(), isKnownASCII: _guts.isASCII
+      )
+    }
+  }
+#endif // !(os(watchOS) && _pointerBitWidth(_32))
+}
+
+@available(SwiftStdlib 6.2, *)
+extension Substring {
+
+  @lifetime(borrow self)
+  private borrowing func _underlyingSpan() -> Span<UTF8.CodeUnit> {
+#if _runtime(_ObjC)
+    // handle non-UTF8 Objective-C bridging cases here
+    if !_wholeGuts.isFastUTF8, _wholeGuts._object.hasObjCBridgeableObject {
+      let base: String.UTF8View = _slice._base.utf8
+      let first = base._foreignDistance(from: base.startIndex, to: startIndex)
+      let count = base._foreignDistance(from: startIndex, to: endIndex)
+      let span = base._underlyingSpan().extracting(first..<(first &+ count))
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+#endif // _runtime(_ObjC)
+    let first = _slice._startIndex._encodedOffset
+    let end = _slice._endIndex._encodedOffset
+    if _wholeGuts.isSmall {
+      let a = Builtin.addressOfBorrow(self)
+      let offset = first &+ (2 &* MemoryLayout<String.Index>.stride)
+      let start = unsafe UnsafePointer<UTF8.CodeUnit>(a).advanced(by: offset)
+      let span = unsafe Span(_unsafeStart: start, count: end &- first)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+    let isFastUTF8 = _wholeGuts.isFastUTF8
+    _precondition(isFastUTF8, "Substring must be contiguous UTF8")
+    var span = unsafe Span(_unsafeElements: _wholeGuts._object.fastUTF8)
+    span = span.extracting(first..<end)
+    return unsafe _overrideLifetime(span, borrowing: self)
+  }
+
+#if !(os(watchOS) && _pointerBitWidth(_32))
+  /// A UTF-8 span over the code units that make up this substring.
+  ///
+  /// - Note: In the case of bridged UTF-16 string instances (on Apple
+  ///   platforms) this property needs to transcode the code units every time
+  ///   it's called.
+  ///
+  /// For example, if `string` has the bridged UTF-16 representation,
+  /// the following code is accidentally quadratic because of this issue:
+  ///
+  ///     for word in string.split(separator: " ") {
+  ///         useSpan(word.span)
+  ///     }
+  ///
+  /// A workaround is to explicitly convert the string into its native UTF-8
+  /// representation:
+  ///
+  ///     var nativeString = consume string
+  ///     nativeString.makeContiguousUTF8()
+  ///     for word in nativeString.split(separator: " ") {
+  ///         useSpan(word.span)
+  ///     }
+  ///
+  /// This second option has linear time complexity, as expected.
+  ///
+  /// - Returns: A `UTF8Span` over the code units of this substring.
+  ///
+  /// - Complexity: O(1) for native UTF-8 strings, O(n) for bridged UTF-16
+  ///   strings.
+  @available(SwiftStdlib 6.2, *)
+  public var utf8Span: UTF8Span {
+    @lifetime(borrow self)
+    borrowing get {
+      unsafe UTF8Span(
+        unchecked: _underlyingSpan(), isKnownASCII: base._guts.isASCII
+      )
+    }
+  }
+
+  /// A UTF-8 span over the code units that make up this substring.
+  ///
+  /// - Note: In the case of bridged UTF-16 string instances (on Apple
+  ///   platforms) this property needs to transcode the code units every time
+  ///   it's called.
+  ///
+  /// For example, if `string` has the bridged UTF-16 representation,
+  /// the following code is accidentally quadratic because of this issue:
+  ///
+  ///     for word in string.split(separator: " ") {
+  ///         useSpan(word.span)
+  ///     }
+  ///
+  /// A workaround is to explicitly convert the string into its native UTF-8
+  /// representation:
+  ///
+  ///     var nativeString = consume string
+  ///     nativeString.makeContiguousUTF8()
+  ///     for word in nativeString.split(separator: " ") {
+  ///         useSpan(word.span)
+  ///     }
+  ///
+  /// This second option has linear time complexity, as expected.
+  ///
+  /// - Returns: A `UTF8Span` over the code units of this substring.
+  ///
+  /// - Complexity: O(1) for native UTF-8 strings, O(n) for bridged UTF-16
+  ///   strings.
+  @available(SwiftStdlib 6.2, *)
+  public var _utf8Span: UTF8Span? {
+    @_alwaysEmitIntoClient @inline(__always)
+    @lifetime(borrow self)
+    borrowing get {
+      utf8Span
+    }
+  }
+#else // !(os(watchOS) && _pointerBitWidth(_32))
+  @available(watchOS, unavailable)
+  public var utf8Span: UTF8Span {
+    fatalError("\(#function) unavailable on 32-bit watchOS")
+  }
+
+  /// A UTF-8 span over the code units that make up this substring.
+  ///
+  /// - Note: In the case of bridged UTF-16 string instances (on Apple
+  ///   platforms) this property needs to transcode the code units every time
+  ///   it's called.
+  ///
+  /// For example, if `string` has the bridged UTF-16 representation,
+  /// the following code is accidentally quadratic because of this issue:
+  ///
+  ///     for word in string.split(separator: " ") {
+  ///         useSpan(word.span)
+  ///     }
+  ///
+  /// A workaround is to explicitly convert the string into its native UTF-8
+  /// representation:
+  ///
+  ///     var nativeString = consume string
+  ///     nativeString.makeContiguousUTF8()
+  ///     for word in nativeString.split(separator: " ") {
+  ///         useSpan(word.span)
+  ///     }
+  ///
+  /// This second option has linear time complexity, as expected.
+  ///
+  /// - Returns: A `UTF8Span` over the code units of this substring, or `nil`
+  ///   if the substring does not have a contiguous representation.
+  ///
+  /// - Complexity: O(1) for native UTF-8 strings, O(n) for bridged UTF-16
+  ///   strings.
+  @available(SwiftStdlib 6.2, *)
+  public var _utf8Span: UTF8Span? {
+    @lifetime(borrow self)
+    borrowing get {
+      if _wholeGuts.isSmall,
+         _wholeGuts.count > _SmallString.contiguousCapacity() {
+        // substring is spannable only when the whole string is spannable.
+        return nil
+      }
+      return unsafe UTF8Span(
+        unchecked: _underlyingSpan(), isKnownASCII: base._guts.isASCII
+      )
+    }
+  }
+#endif // !(os(watchOS) && _pointerBitWidth(_32))
+}
diff --git a/stdlib/public/core/UTF8SpanBits.swift b/stdlib/public/core/UTF8SpanBits.swift
new file mode 100644
index 0000000000000..1cda0c5cb8353
--- /dev/null
+++ b/stdlib/public/core/UTF8SpanBits.swift
@@ -0,0 +1,148 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Returns whether contents are known to be all-ASCII. A return value of
+  /// `true` means that all code units are ASCII. A return value of `false`
+  /// means there _may_ be non-ASCII content.
+  ///
+  /// ASCII-ness is checked and remembered during UTF-8 validation, so this
+  /// is often equivalent to is-ASCII, but there are some situations where
+  /// we might return `false` even when the content happens to be all-ASCII.
+  ///
+  /// For example, a UTF-8 span generated from a `String` that at some point
+  /// contained non-ASCII content would report false for `isKnownASCII`, even
+  /// if that String had subsequent mutation operations that removed any
+  /// non-ASCII content.
+  ///
+  /// - Complexity: O(1)
+  @_alwaysEmitIntoClient
+  public var isKnownASCII: Bool {
+    0 != _countAndFlags & Self._asciiBit
+  }
+
+  /// Do a scan checking for whether the contents are all-ASCII.
+  ///
+  /// Updates the `isKnownASCII` bit if contents are all-ASCII.
+  ///
+  /// - Complexity: O(n)
+  @lifetime(self: copy self)
+  public mutating func checkForASCII() -> Bool {
+    if isKnownASCII { return true }
+
+    let result = unsafe _withUnsafeBufferPointer {
+      unsafe _allASCII($0)
+    }
+    if result {
+      _setIsASCII()
+    }
+    return result
+  }
+
+  /// Returns whether the contents are known to be NFC. This is not
+  /// always checked at initialization time and is set by `checkForNFC`.
+  ///
+  /// - Complexity: O(1)
+  @_alwaysEmitIntoClient
+  public var isKnownNFC: Bool {
+    0 != _countAndFlags & Self._nfcBit
+  }
+
+  // Set the isKnownASCII bit to true (also isNFC)
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  internal mutating func _setIsASCII() {
+    self._countAndFlags |= Self._asciiBit | Self._nfcBit
+  }
+
+  // Set the isKnownNFC bit to true (also isNFC)
+  @_alwaysEmitIntoClient
+  @lifetime(self: copy self)
+  internal mutating func _setIsNFC() {
+    self._countAndFlags |= Self._nfcBit
+  }
+
+  /// Do a scan checking for whether the contents are in Normal Form C.
+  /// When the contents are in NFC, canonical equivalence checks are much
+  /// faster.
+  ///
+  /// `quickCheck` will check for a subset of NFC contents using the
+  /// NFCQuickCheck algorithm, which is faster than the full normalization
+  /// algorithm. However, it cannot detect all NFC contents.
+  ///
+  /// Updates the `isKnownNFC` bit.
+  ///
+  /// - Complexity: O(n)
+  @_unavailableInEmbedded
+  @lifetime(self: copy self)
+  public mutating func checkForNFC(
+    quickCheck: Bool
+  ) -> Bool {
+    if isKnownNFC { return true }
+
+    if quickCheck {
+      let result = unsafe _withUnsafeBufferPointer { utf8 in
+        var prevCCC: UInt8 = 0
+        return unsafe _nfcQuickCheck(utf8, prevCCC: &prevCCC)
+      }
+      if result {
+        self._countAndFlags |= Self._nfcBit
+      }
+      return result
+    }
+
+    // TODO: use faster internal algorithm
+    let normalized = _str._nfcCodeUnits
+    guard unsafe _start()._urbp(
+      0..<count
+    ).elementsEqual(normalized) else {
+      return false
+    }
+
+    self._countAndFlags |= Self._nfcBit
+    return true
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  @_alwaysEmitIntoClient @inline(__always)
+  internal static var _asciiBit: UInt64 {
+    0x8000_0000_0000_0000
+  }
+
+  @_alwaysEmitIntoClient @inline(__always)
+  internal static var _nfcBit: UInt64 {
+    0x4000_0000_0000_0000
+  }
+
+  @_alwaysEmitIntoClient @inline(__always)
+  internal static var _countMask: UInt64 {
+    0x00FF_FFFF_FFFF_FFFF
+  }
+
+  @_alwaysEmitIntoClient @inline(__always)
+  internal static var _flagsMask: UInt64 {
+    0xFF00_0000_0000_0000
+  }
+
+  /// The number of UTF-8 code units in the span.
+  ///
+  /// - Complexity: O(1)
+  @_alwaysEmitIntoClient
+  public var count: Int {
+    Int(truncatingIfNeeded: _countAndFlags & Self._countMask)
+  }
+}
+
+
diff --git a/stdlib/public/core/UTF8SpanComparisons.swift b/stdlib/public/core/UTF8SpanComparisons.swift
new file mode 100644
index 0000000000000..6dee10378d75e
--- /dev/null
+++ b/stdlib/public/core/UTF8SpanComparisons.swift
@@ -0,0 +1,119 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Whether this span has the same bytes as `other`.
+  ///
+  /// - Complexity: O(n)
+  @_alwaysEmitIntoClient
+  public func bytesEqual(to other: some Sequence<UInt8>) -> Bool {
+    unsafe _withUnsafeBufferPointer { unsafe $0.elementsEqual(other) }
+  }
+
+  /// Whether this span has the same `Unicode.Scalar`s as `other`.
+  ///
+  /// - Complexity: O(n)
+  @_alwaysEmitIntoClient
+  public func unicodeScalarsEqual(
+    to other: some Sequence<Unicode.Scalar>
+  ) -> Bool {
+    // TODO: We don't need to decode our code units, we can just match
+    // against their scalars' encoded bytes
+
+    var scalars = makeUnicodeScalarIterator()
+    var otherScalars = other.makeIterator()
+    while let s = scalars.next() {
+      guard let otherS = otherScalars.next(), s == otherS else {
+        return false
+      }
+    }
+    guard scalars.next() == nil else {
+      return false
+    }
+    return true
+  }
+
+  /// Whether this span has the same `Character`s as `other`.
+  ///
+  /// - Complexity: O(n)
+  @_unavailableInEmbedded
+  @_alwaysEmitIntoClient
+  public func charactersEqual(
+    to other: some Sequence<Character>
+  ) -> Bool {
+    var chars = makeCharacterIterator()
+    var otherChars = other.makeIterator()
+    while let c = chars.next() {
+      guard let otherC = otherChars.next(), c == otherC else {
+        return false
+      }
+    }
+    guard chars.next() == nil else {
+      return false
+    }
+    return true
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Whether `self` is equivalent to `other` under Unicode Canonical
+  /// Equivalence.
+  ///
+  /// - Complexity: O(n)
+  public func isCanonicallyEquivalent(
+    to other: UTF8Span
+  ) -> Bool {
+    unsafe self._withUnsafeBufferPointer { selfBufPtr in
+      unsafe other._withUnsafeBufferPointer { otherBufPtr in
+        unsafe _stringCompareFastUTF8(
+          selfBufPtr,
+          otherBufPtr,
+          expecting: .equal,
+          bothNFC: self.isKnownNFC && other.isKnownNFC)
+      }
+    }
+  }
+
+  /// Whether `self` orders less than `other` under Unicode Canonical
+  /// Equivalence using normalized code-unit order (in NFC).
+  ///
+  /// - Complexity: O(n)
+  public func isCanonicallyLessThan(
+    _ other: UTF8Span
+  ) -> Bool {
+    unsafe self._withUnsafeBufferPointer { selfBufPtr in
+      unsafe other._withUnsafeBufferPointer { otherBufPtr in
+        unsafe _stringCompareFastUTF8(
+          selfBufPtr,
+          otherBufPtr,
+          expecting: .less,
+          bothNFC: self.isKnownNFC && other.isKnownNFC)
+      }
+    }
+  }
+}
+
+// // FIXME: remove
+// @available(SwiftStdlib 6.2, *)
+// extension UTF8Span {
+//   public static func ~=(_ lhs: StaticString, _ rhs: UTF8Span) -> Bool {
+//     return lhs.withUTF8Buffer { str in
+//       rhs._withUnsafeBufferPointer { span in
+//         str.elementsEqual(span)
+//       }
+//     }
+//   }
+// }
+
+
diff --git a/stdlib/public/core/UTF8SpanFundamentals.swift b/stdlib/public/core/UTF8SpanFundamentals.swift
new file mode 100644
index 0000000000000..defddbdfe033c
--- /dev/null
+++ b/stdlib/public/core/UTF8SpanFundamentals.swift
@@ -0,0 +1,372 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// Core Scalar API
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Whether `i` is on a boundary between Unicode scalar values.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  internal func _isScalarAligned(unchecked i: Int) -> Bool {
+    if i == count || i == 0 { return true }
+    _internalInvariant(_boundsCheck(i))
+    return unsafe _start()._isScalarAligned(i)
+  }
+
+  /// Returns the start of the `Unicode.Scalar` ending at `i`, i.e. the scalar
+  /// before the one starting at `i` or the last scalar if `i` is the end of
+  /// the span.
+  ///
+  /// `i` must be scalar-aligned.
+  internal func _previousScalarStart(_ i: Int) -> Int {
+    _precondition(_boundsCheck(i&-1))
+    return _previousScalarStart(unchecked: i)
+  }
+
+  /// Returns the start of the `Unicode.Scalar` ending at `i`, i.e. the scalar
+  /// before the one starting at `i` or the last scalar if `i` is the end of
+  /// the span.
+  ///
+  /// `i` must be scalar-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  internal func _previousScalarStart(unchecked i: Int) -> Int {
+    _internalInvariant(_boundsCheck(i&-1))
+    _precondition(_isScalarAligned(unchecked: i))
+    return _previousScalarStart(uncheckedAssumingAligned: i)
+  }
+
+  /// Returns the start of the `Unicode.Scalar` ending at `i`, i.e. the scalar
+  /// before the one starting at `i` or the last scalar if `i` is the end of
+  /// the span.
+  ///
+  /// `i` must be scalar-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  ///
+  ///
+  /// This function does not validate that `i` is scalar-aligned; this is an
+  /// unsafe operation if `i` isn't.
+  internal func _previousScalarStart(
+    uncheckedAssumingAligned i: Int
+  ) -> Int {
+    _internalInvariant(_boundsCheck(i&-1))
+    _internalInvariant(_isScalarAligned(unchecked: i))
+    return unsafe _start()._previousScalarStart(i)
+  }
+
+  /// Decode the `Unicode.Scalar` starting at `i`. Return it and the start of
+  /// the next scalar.
+  ///
+  /// `i` must be scalar-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  ///
+  ///
+  /// This function does not validate that `i` is scalar-aligned; this is an
+  /// unsafe operation if `i` isn't.
+  internal func _decodeNextScalar(
+    uncheckedAssumingAligned i: Int
+  ) -> (Unicode.Scalar, nextScalarStart: Int) {
+    _internalInvariant(_boundsCheck(i))
+    _internalInvariant(_isScalarAligned(unchecked: i))
+    return unsafe _start()._decodeScalar(startingAt: i)
+  }
+
+  /// Decode the `Unicode.Scalar` ending at `i`, i.e. the previous scalar.
+  /// Return it and the start of that scalar.
+  ///
+  /// `i` must be scalar-aligned.
+  internal func _decodePreviousScalar(
+    _ i: Int
+  ) -> (Unicode.Scalar, previousScalarStart: Int) {
+    _precondition(_boundsCheck(i &- 1))
+    return _decodePreviousScalar(unchecked: i)
+  }
+
+  /// Decode the `Unicode.Scalar` ending at `i`, i.e. the previous scalar.
+  /// Return it and the start of that scalar.
+  ///
+  /// `i` must be scalar-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  internal func _decodePreviousScalar(
+    unchecked i: Int
+  ) -> (Unicode.Scalar, previousScalarStart: Int) {
+    _internalInvariant(_boundsCheck(i &- 1))
+    _precondition(_isScalarAligned(unchecked: i))
+    return _decodePreviousScalar(uncheckedAssumingAligned: i)
+  }
+
+  /// Decode the `Unicode.Scalar` ending at `i`, i.e. the previous scalar.
+  /// Return it and the start of that scalar.
+  ///
+  /// `i` must be scalar-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  ///
+  ///
+  /// This function does not validate that `i` is scalar-aligned; this is an
+  /// unsafe operation if `i` isn't.
+  internal func _decodePreviousScalar(
+    uncheckedAssumingAligned i: Int
+  ) -> (Unicode.Scalar, previousScalarStart: Int) {
+    _internalInvariant(_boundsCheck(i &- 1))
+    _internalInvariant(_isScalarAligned(unchecked: i))
+    return unsafe _start()._decodeScalar(endingAt: i)
+  }
+}
+
+// Derived Scalar API
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Find the nearest scalar-aligned position `<= i`.
+  internal func _scalarAlignBackwards(_ i: Int) -> Int {
+    if i == count || i == 0 { return i }
+
+    _precondition(_boundsCheck(i))
+    return unsafe _start()._scalarAlign(i)
+  }
+
+  /// Find the nearest scalar-aligned position `>= i`.
+  internal func _scalarAlignForwards(_ i: Int) -> Int {
+    // FIXME: do the bounds check
+    // FIXME: stop at end of code units
+    //   - this should be an invariant, but checking it lets us avoid ever
+    //     reading off the end
+    // FIXME: implement directly
+    var i = i
+    while _slowPath(!_isScalarAligned(unchecked: i)) {
+      i &+= 1
+    }
+    return i
+  }
+
+  /// Find the nearest scalar-aligned position `>= i`.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  internal func _scalarAlignForwards(unchecked i: Int) -> Int {
+    if i == count || i == 0 { return i }
+
+    var i = i
+    while _slowPath(!_isScalarAligned(unchecked: i)) {
+      i &+= 1
+    }
+    return i
+  }
+}
+
+// Core Character API
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Returns the start of the next `Character` (i.e. grapheme cluster) after
+  /// the one  starting at `i`, or the end of the span if `i` denotes the final
+  /// `Character`.
+  ///
+  /// `i` must be `Character`-aligned.
+  internal func _nextCharacterStart(_ i: Int) -> Int {
+    _precondition(_boundsCheck(i))
+    return _nextCharacterStart(unchecked: i)
+  }
+
+  /// Returns the start of the next `Character` (i.e. grapheme cluster) after
+  /// the one  starting at `i`, or the end of the span if `i` denotes the final
+  /// `Character`.
+  ///
+  /// `i` must be `Character`-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  internal func _nextCharacterStart(unchecked i: Int) -> Int {
+    _internalInvariant(_boundsCheck(i))
+    _precondition(_isScalarAligned(unchecked: i))
+    return _nextCharacterStart(uncheckedAssumingAligned: i)
+  }
+
+  /// Returns the start of the next `Character` (i.e. grapheme cluster) after
+  /// the one  starting at `i`, or the end of the span if `i` denotes the final
+  /// `Character`.
+  ///
+  /// `i` must be `Character`-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  ///
+  /// This function does not validate that `i` is `Character`-aligned; this is
+  /// an unsafe operation if `i` isn't.
+  internal func _nextCharacterStart(
+    uncheckedAssumingAligned i: Int
+  ) -> Int {
+    _internalInvariant(_boundsCheck(i))
+    _internalInvariant(_isScalarAligned(unchecked: i))
+    return unsafe _start()._nextCharacterStart(i, limitedBy: count)
+  }
+
+  /// Returns the start of the `Character` (i.e. grapheme cluster) ending at
+  /// `i`, i.e. the `Character` before the one starting at `i` or the last
+  /// `Character` if `i` is the end of the span.
+  ///
+  /// `i` must be `Character`-aligned.
+  internal func _previousCharacterStart(_ i: Int) -> Int {
+    _precondition(_boundsCheck(i&-1))
+    return _previousCharacterStart(unchecked: i)
+  }
+
+  /// Returns the start of the `Character` (i.e. grapheme cluster) ending at
+  /// `i`, i.e. the `Character` before the one starting at `i` or the last
+  /// `Character` if `i` is the end of the span.
+  ///
+  /// `i` must be `Character`-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  internal func _previousCharacterStart(unchecked i: Int) -> Int {
+    _internalInvariant(_boundsCheck(i&-1))
+    _precondition(_isScalarAligned(unchecked: i))
+    return _previousCharacterStart(uncheckedAssumingAligned: i)
+  }
+
+  /// Returns the start of the `Character` (i.e. grapheme cluster) ending at
+  /// `i`, i.e. the `Character` before the one starting at `i` or the last
+  /// `Character` if `i` is the end of the span.
+  ///
+  /// `i` must be `Character`-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  ///
+  /// This function does not validate that `i` is `Character`-aligned; this is
+  /// an unsafe operation if `i` isn't.
+  internal func _previousCharacterStart(
+    uncheckedAssumingAligned i: Int
+  ) -> Int {
+    _internalInvariant(_boundsCheck(i&-1))
+    _internalInvariant(_isScalarAligned(unchecked: i))
+    return unsafe _start()._previousCharacterStart(i, limitedBy: count)
+  }
+
+  /// Decode the `Character` starting at `i` Return it and the start of the
+  /// next `Character`.
+  ///
+  /// `i` must be `Character`-aligned.
+  internal func _decodeNextCharacter(
+    _ i: Int
+  ) -> (Character, nextCharacterStart: Int) {
+    _precondition(_boundsCheck(i))
+    return _decodeNextCharacter(unchecked: i)
+  }
+
+  /// Decode the `Character` starting at `i` Return it and the start of the
+  /// next `Character`.
+  ///
+  /// `i` must be `Character`-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  internal func _decodeNextCharacter(
+    unchecked i: Int
+  ) -> (Character, nextCharacterStart: Int) {
+    _internalInvariant(_boundsCheck(i))
+    _precondition(_isScalarAligned(unchecked: i))
+    return _decodeNextCharacter(uncheckedAssumingAligned: i)
+  }
+
+  /// Decode the `Character` starting at `i` Return it and the start of the
+  /// next `Character`.
+  ///
+  /// `i` must be `Character`-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  ///
+  /// This function does not validate that `i` is `Character`-aligned; this is
+  /// an unsafe operation if `i` isn't.
+  internal func _decodeNextCharacter(
+    uncheckedAssumingAligned i: Int
+  ) -> (Character, nextCharacterStart: Int) {
+    _internalInvariant(_boundsCheck(i))
+    _internalInvariant(_isScalarAligned(unchecked: i))
+    return unsafe _start()._decodeCharacter(
+      startingAt: i, limitedBy: count)
+  }
+
+  /// Decode the `Character` (i.e. grapheme cluster) ending at `i`, i.e. the
+  /// previous `Character`. Return it and the start of that `Character`.
+  ///
+  /// `i` must be `Character`-aligned.
+  internal func _decodePreviousCharacter(_ i: Int) -> (Character, Int) {
+    _precondition(_boundsCheck(i &- 1))
+    return _decodePreviousCharacter(unchecked: i)
+  }
+
+  /// Decode the `Character` (i.e. grapheme cluster) ending at `i`, i.e. the
+  /// previous `Character`. Return it and the start of that `Character`.
+  ///
+  /// `i` must be `Character`-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  internal func _decodePreviousCharacter(
+    unchecked i: Int
+  ) -> (Character, Int) {
+    _internalInvariant(_boundsCheck(i &- 1))
+    _precondition(_isScalarAligned(unchecked: i))
+    return _decodePreviousCharacter(uncheckedAssumingAligned: i)
+  }
+
+  /// Decode the `Character` (i.e. grapheme cluster) ending at `i`, i.e. the
+  /// previous `Character`. Return it and the start of that `Character`.
+  ///
+  /// `i` must be `Character`-aligned.
+  ///
+  /// This function does not validate that `i` is within the span's bounds;
+  /// this is an unsafe operation.
+  ///
+  /// This function does not validate that `i` is `Character`-aligned; this is
+  /// an unsafe operation if `i` isn't.
+  internal func _decodePreviousCharacter(
+    uncheckedAssumingAligned i: Int
+  ) -> (Character, Int) {
+    _internalInvariant(_boundsCheck(i &- 1))
+    _internalInvariant(_isScalarAligned(unchecked: i))
+    return unsafe _start()._decodeCharacter(
+      endingAt: i, limitedBy: count)
+  }
+
+}
+
+// TODO: internal?
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Whether `i` is in bounds
+  @_alwaysEmitIntoClient
+  internal func _boundsCheck(_ i: Int) -> Bool {
+    i >= 0 && i < count
+  }
+  /// Whether `bounds` is in bounds
+  @_alwaysEmitIntoClient
+  internal func _boundsCheck(_ bounds: Range<Int>) -> Bool {
+    _boundsCheck(bounds.lowerBound)
+    && _boundsCheck(bounds.upperBound &- 1)
+  }
+}
+
+// Future work: UTF-16 support when we get views
+
+
diff --git a/stdlib/public/core/UTF8SpanInternalHelpers.swift b/stdlib/public/core/UTF8SpanInternalHelpers.swift
new file mode 100644
index 0000000000000..f0b57b4612e80
--- /dev/null
+++ b/stdlib/public/core/UTF8SpanInternalHelpers.swift
@@ -0,0 +1,185 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// TODO: Should we update our unicode helpers file to call these instead?
+
+// import Builtin
+
+extension UnsafeRawPointer {
+  // @_alwaysEmitIntoClient
+  internal func _loadByte(_ i: Int) -> UInt8 {
+    _internalInvariant(i >= 0)
+    return unsafe (self+i).loadUnaligned(as: UInt8.self)
+  }
+
+  // @_alwaysEmitIntoClient
+  internal func _isUTF8Continuation(_ i: Int) -> Bool {
+    unsafe UTF8.isContinuation(_loadByte(i))
+  }
+
+  // @_alwaysEmitIntoClient
+  internal func _isScalarAligned(_ i: Int) -> Bool {
+    _internalInvariant(i >= 0)
+    return unsafe !_isUTF8Continuation(i)
+  }
+
+  // @_alwaysEmitIntoClient
+  internal func _scalarLength(startingAt i: Int) -> Int {
+    unsafe _utf8ScalarLength(_loadByte(i))
+  }
+
+  // NOTE: Adaptation of `_decodeScalar` to work on URP
+//  @_alwaysEmitIntoClient
+  internal func _decodeScalar(
+    startingAt i: Int
+  ) -> (Unicode.Scalar, nextScalarStart: Int) {
+    let cu0 = unsafe _loadByte(i)
+    let len = _utf8ScalarLength(cu0)
+    let next = len &+ i
+    switch  len {
+    case 1: return (_decodeUTF8(cu0), next)
+    case 2: return unsafe (_decodeUTF8(cu0, _loadByte(i &+ 1)), next)
+    case 3: return unsafe (
+      _decodeUTF8(cu0, _loadByte(i &+ 1), _loadByte(i &+ 2)), next
+    )
+    case 4:
+      return (
+        unsafe _decodeUTF8(
+          cu0, _loadByte(i &+ 1), _loadByte(i &+ 2), _loadByte(i &+ 3)
+        ),
+        next
+      )
+    default: Builtin.unreachable()
+    }
+  }
+
+  // @_alwaysEmitIntoClient
+  internal func _decodeScalar(
+    endingAt i: Int
+  ) -> (Unicode.Scalar, previousScalarStart: Int) {
+    // TODO: no need to double load the bytes...
+    let start = unsafe _previousScalarStart(i)
+    return unsafe (_decodeScalar(startingAt: start).0, start)
+  }
+
+  // @_alwaysEmitIntoClient
+  internal func _previousScalarStart(_ i: Int) -> Int {
+    var prev = i &- 1
+    _internalInvariant(prev >= 0)
+    while unsafe _isUTF8Continuation(prev) {
+      prev &-= 1
+      _internalInvariant(prev >= 0)
+    }
+    _internalInvariant(unsafe i == prev + _utf8ScalarLength(_loadByte(prev)))
+    return prev
+  }
+
+  // @_alwaysEmitIntoClient
+  internal func _scalarAlign(_ i: Int) -> Int {
+    var i = i
+    while _slowPath(unsafe !_isScalarAligned(i)) {
+      i &-= 1
+    }
+    return i
+  }
+}
+
+extension UnsafeRawPointer {
+  // TODO: ASCII fast path wrappers around ufi functions
+
+  // TODO: hook up to real grapheme breaking
+  internal func _urbp(_ range: Range<Int>) -> UnsafeRawBufferPointer {
+    unsafe .init(start: self + range.lowerBound, count: range.count)
+  }
+
+  @_alwaysEmitIntoClient
+  internal func _ubp(_ range: Range<Int>) -> UnsafeBufferPointer<UInt8> {
+    unsafe UnsafeBufferPointer<UInt8>(
+      start: UnsafePointer((self+range.lowerBound)._rawValue),
+      count: range.count)
+  }
+
+  internal func _str(_ range: Range<Int>) -> String {
+    unsafe String(decoding: _urbp(range) , as: UTF8.self)
+  }
+
+  // @usableFromInline
+  internal func _nextCharacterStart(
+    _ i: Int, limitedBy end: Int
+  ) -> Int {
+    _internalInvariant((0..<end).contains(i))
+    _internalInvariant(unsafe _isScalarAligned(i))
+
+    return _nextGraphemeClusterBoundary(startingAt: i) { idx in
+      guard idx < end else { return nil }
+      let (scalar, end) = unsafe _decodeScalar(startingAt: idx)
+      return (scalar, end)
+    }
+  }
+
+  // @usableFromInline
+  internal func _previousCharacterStart(
+    _ i: Int,
+    limitedBy end: Int
+  ) -> Int {
+    _internalInvariant(i > 0 && i <= end)
+    _internalInvariant(unsafe i == end || _isScalarAligned(i))
+
+    return _previousGraphemeClusterBoundary(endingAt: i) { idx in
+      guard idx > 0 else { return nil }
+      let (scalar, prior) = unsafe _decodeScalar(endingAt: idx)
+      return (scalar, prior)
+    }
+  }
+
+  // @usableFromInline
+  internal func _decodeCharacter(
+    startingAt i: Int, limitedBy end: Int
+  ) -> (Character, nextCharacterStart: Int) {
+    let nextStart = unsafe _nextCharacterStart(i, limitedBy: end)
+    return unsafe (Character(_str(i..<nextStart)), nextStart)
+  }
+
+  // @usableFromInline
+  internal func _decodeCharacter(
+    endingAt i: Int,
+    limitedBy end: Int
+  ) -> (Character, nextCharacterStart: Int) {
+    let start = unsafe _previousCharacterStart(i, limitedBy: end)
+    _internalInvariant(start >= 0)
+
+    return unsafe (Character(_str(start..<i)), start)
+  }
+
+}
+
+@available(SwiftStdlib 6.2, *)
+extension UnsafeRawPointer {
+  internal enum _UTF8ValidationResult {
+    case success(isASCII: Bool)
+    case error(_: Range<Int>)
+  }
+
+  // Returns isASCII
+  // TODO: return more values
+  internal func _validateUTF8(
+    limitedBy end: Int
+  ) throws(UTF8.ValidationError) -> Bool {
+    switch unsafe validateUTF8(_ubp(0..<end)) {
+    case .success(let info):
+      return info.isASCII
+    case .error(let kind, let range):
+      throw UTF8.ValidationError(kind._publicKind, range)
+    }
+  }
+
+}
diff --git a/stdlib/public/core/UTF8SpanIterators.swift b/stdlib/public/core/UTF8SpanIterators.swift
new file mode 100644
index 0000000000000..605ec3ee4cb6c
--- /dev/null
+++ b/stdlib/public/core/UTF8SpanIterators.swift
@@ -0,0 +1,458 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  /// Returns an iterator that will decode the code units into
+  /// `Unicode.Scalar`s.
+  ///
+  /// The resulting iterator has the same lifetime constraints as `self`.
+  @lifetime(copy self)
+  public func makeUnicodeScalarIterator() -> UnicodeScalarIterator {
+    .init(self)
+  }
+
+  /// Iterate the `Unicode.Scalar`s contents of a `UTF8Span`.
+  ///
+  ///     func printScalarValues(_ string: borrowing String) {
+  ///         var iterator = string.utf8Span.makeUnicodeScalarIterator()
+  ///         while let scalar = iterator.next() {
+  ///             print(scalar.escaped(asASCII: true))
+  ///         }
+  ///     }
+  ///
+  ///     let string = "A🎉"
+  ///     printScalarValues(string)
+  ///     // Prints "A"
+  ///     // Prints "\u{0001F389}"
+  @frozen
+  public struct UnicodeScalarIterator: ~Escapable {
+    public let codeUnits: UTF8Span
+
+    /// The byte offset of the start of the next scalar. This is
+    /// always scalar-aligned.
+    fileprivate(set)
+    public var currentCodeUnitOffset: Int
+
+    @lifetime(copy codeUnits)
+    public init(_ codeUnits: UTF8Span) {
+      self.codeUnits = codeUnits
+      self.currentCodeUnitOffset = 0
+    }
+
+    private var _start: UnsafeRawPointer {
+      unsafe codeUnits._start()
+    }
+
+    /// Decode and return the scalar starting at `currentCodeUnitOffset`.
+    /// After the function returns, `currentCodeUnitOffset` holds the
+    /// position at the end of the returned scalar, which is also the start
+    /// of the next scalar.
+    ///
+    /// Returns `nil` if at the end of the `UTF8Span`.
+    ///
+    /// - Complexity: O(1)
+    @lifetime(self: copy self)
+    public mutating func next() -> Unicode.Scalar? {
+      guard currentCodeUnitOffset < codeUnits.count else {
+        return nil
+      }
+
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: currentCodeUnitOffset))
+      let (result, newPos) = unsafe _start._decodeScalar(startingAt: currentCodeUnitOffset)
+      self.currentCodeUnitOffset = newPos
+      return result
+    }
+
+    /// Decode and return the scalar ending at `currentCodeUnitOffset`. After
+    /// the function returns, `currentCodeUnitOffset` holds the position at
+    /// the start of the returned scalar, which is also the end of the
+    /// previous scalar.
+    ///
+    /// Returns `nil` if at the start of the `UTF8Span`.
+    ///
+    /// - Complexity: O(1)
+    @lifetime(self: copy self)
+    public mutating func previous() -> Unicode.Scalar? {
+      guard currentCodeUnitOffset > 0 else {
+        return nil
+      }
+
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: currentCodeUnitOffset))
+      let (result, newPos) = unsafe _start._decodeScalar(endingAt: currentCodeUnitOffset)
+      self.currentCodeUnitOffset = newPos
+      return result
+    }
+
+
+    /// Advance `codeUnitOffset` to the end of the current scalar, without
+    /// decoding it.
+    ///
+    /// Returns the number of `Unicode.Scalar`s skipped over, which can be 0
+    /// if at the end of the UTF8Span.
+    ///
+    /// - Complexity: O(1)
+    @lifetime(self: copy self)
+    public mutating func skipForward() -> Int {
+      guard currentCodeUnitOffset < codeUnits.count else {
+        return 0
+      }
+
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: currentCodeUnitOffset))
+
+      currentCodeUnitOffset &+= unsafe _start._scalarLength(startingAt: currentCodeUnitOffset)
+      return 1
+    }
+
+    /// Advance `codeUnitOffset` to the end of `n` scalars, without decoding
+    /// them.
+    ///
+    /// Returns the number of `Unicode.Scalar`s skipped over, which can be
+    /// fewer than `n` if at the end of the UTF8Span.
+    ///
+    /// - Complexity: O(n)
+    @lifetime(self: copy self)
+    public mutating func skipForward(by n: Int) -> Int {
+      var numSkipped = 0
+      while numSkipped < n && skipForward() != 0 {
+        numSkipped += 1
+      }
+
+      return numSkipped
+    }
+
+    /// Move `codeUnitOffset` to the start of the previous scalar, without
+    /// decoding it.
+    ///
+    /// Returns the number of `Unicode.Scalar`s skipped over, which can be 0
+    /// if at the start of the UTF8Span.
+    ///
+    /// - Complexity: O(1)
+    @lifetime(self: copy self)
+    public mutating func skipBack() -> Int {
+      guard currentCodeUnitOffset > 0 else {
+        return 0
+      }
+
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: currentCodeUnitOffset))
+
+      currentCodeUnitOffset = unsafe _start._previousScalarStart(currentCodeUnitOffset)
+      return 1
+    }
+
+    /// Move `codeUnitOffset` to the start of the previous `n` scalars,
+    /// without decoding them.
+    ///
+    /// Returns the number of `Unicode.Scalar`s skipped over, which can be
+    /// fewer than `n` if at the start of the UTF8Span.
+    ///
+    /// - Complexity: O(n)
+    @lifetime(self: copy self)
+    public mutating func skipBack(by n: Int) -> Int {
+      var numSkipped = 0
+      while numSkipped < n && skipBack() != 0 {
+        numSkipped += 1
+      }
+
+      return numSkipped
+    }
+
+    /// Reset to the nearest scalar-aligned code unit offset `<= i`.
+    ///
+    ///     func printScalarAfterReset(_ string: borrowing String) {
+    ///         var iterator = string.utf8Span.makeUnicodeScalarIterator()
+    ///         iterator.reset(roundingBackwardsFrom: 8)  // Position 8 is mid-emoji, rounds back to 6
+    ///         if let scalar = iterator.next() {
+    ///             print(scalar)  // Prints "🌍" (emoji starts at byte 6)
+    ///         }
+    ///     }
+    ///     let string = "Hello 🌍"
+    ///     printScalarAfterReset(string)
+    ///
+    /// - Complexity: O(1)
+    @lifetime(self: copy self)
+    public mutating func reset(roundingBackwardsFrom i: Int)  {
+      self.currentCodeUnitOffset = codeUnits._scalarAlignBackwards(i)
+    }
+
+    /// Reset to the nearest scalar-aligned code unit offset `>= i`.
+    ///
+    /// - Complexity: O(1)
+    @lifetime(self: copy self)
+    public mutating func reset(roundingForwardsFrom i: Int)  {
+      self.currentCodeUnitOffset = codeUnits._scalarAlignForwards(i)
+    }
+
+    // TODO: for below, verify that there is no path to UB, just garabage-data or guaranteed
+    // trap!
+
+    /// Reset this iterator to `codeUnitOffset`, skipping _all_ safety
+    /// checks (including bounds checks).
+    ///
+    /// Note: This is only for very specific, low-level use cases. If
+    /// `codeUnitOffset` is not properly scalar-aligned, this function can
+    /// result in undefined behavior when, e.g., `next()` is called.
+    ///
+    /// For example, this could be used by a regex engine to backtrack to a
+    /// known-valid previous position.
+    ///
+    ///
+    /// - Complexity: O(1)
+    @unsafe
+    @lifetime(self: copy self)
+    public mutating func reset(toUnchecked codeUnitOffset: Int) {
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: codeUnitOffset))
+      self.currentCodeUnitOffset = codeUnitOffset
+    }
+
+    /// Returns the UTF8Span containing all the content up to the iterator's
+    /// current position.
+    ///
+    /// The resultant `UTF8Span` has the same lifetime constraints as `self`.
+    ///
+    /// - Complexity: O(1)
+    @lifetime(copy self)
+    public func prefix() -> UTF8Span {
+      let slice = codeUnits.span.extracting(0..<currentCodeUnitOffset)
+      return UTF8Span(
+        _uncheckedAssumingValidUTF8: slice,
+        isKnownASCII: codeUnits.isKnownASCII,
+        isKnownNFC: codeUnits.isKnownNFC)
+    }
+
+    /// Returns the UTF8Span containing all the content after the iterator's
+    /// current position.
+    ///
+    /// The resultant `UTF8Span` has the same lifetime constraints as `self`.
+    ///
+    /// - Complexity: O(1)
+    @lifetime(copy self)
+    public func suffix() -> UTF8Span {
+      let slice = codeUnits.span.extracting(currentCodeUnitOffset..<codeUnits.count)
+      return UTF8Span(
+        _uncheckedAssumingValidUTF8: slice,
+        isKnownASCII: codeUnits.isKnownASCII,
+        isKnownNFC: codeUnits.isKnownNFC)
+    }
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+@_unavailableInEmbedded
+extension UTF8Span {
+  /// Returns an iterator that will construct `Character`s from the underlying
+  /// UTF-8 content.
+  ///
+  /// The resulting iterator has the same lifetime constraints as `self`.
+  @lifetime(copy self)
+  public func makeCharacterIterator() -> CharacterIterator {
+    .init(self)
+  }
+
+  /// Iterate the `Character` contents of a `UTF8Span`.
+  ///
+  ///     func countCharacters(_ string: borrowing String) {
+  ///         var iterator = string.utf8Span.makeCharacterIterator()
+  ///         var count = 0
+  ///         while let character = iterator.next() {
+  ///             count += 1
+  ///             print("Character \(count): \(character)")
+  ///         }
+  ///         print("Total: \(count) characters")
+  ///     }
+  ///
+  ///     let string = "لاهور"
+  ///     countCharacters(string)
+  ///     // Prints "Character 1: ل"
+  ///     // Prints "Character 2: ا"
+  ///     // Prints "Character 3: ه"
+  ///     // Prints "Character 4: و"
+  ///     // Prints "Character 5: ر"
+  ///     // Prints "Total: 5 characters"
+  public struct CharacterIterator: ~Escapable {
+    public let codeUnits: UTF8Span
+
+    /// The byte offset of the start of the next `Character`. This is always
+    /// scalar-aligned. It is always `Character`-aligned relative to the last
+    /// call to `reset` (or the start of the span if not called).
+    fileprivate(set)
+    public var currentCodeUnitOffset: Int
+
+    @lifetime(copy codeUnits)
+    public init(_ codeUnits: UTF8Span) {
+      self.codeUnits = codeUnits
+      self.currentCodeUnitOffset = 0
+    }
+
+    private var _start: UnsafeRawPointer {
+      unsafe codeUnits._start()
+    }
+
+    /// Return the `Character` starting at `currentCodeUnitOffset`. After the
+    /// function returns, `currentCodeUnitOffset` holds the position at the
+    /// end of the `Character`, which is also the start of the next
+    /// `Character`.
+    ///
+    /// Returns `nil` if at the end of the `UTF8Span`.
+    @lifetime(self: copy self)
+    public mutating func next() -> Character? {
+      guard currentCodeUnitOffset < codeUnits.count else { return nil }
+
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: currentCodeUnitOffset))
+      let (result, newPos) = unsafe _start._decodeCharacter(
+        startingAt: currentCodeUnitOffset,
+        limitedBy: codeUnits.count
+      )
+      self.currentCodeUnitOffset = newPos
+      return result
+    }
+
+    /// Return the `Character` ending at `currentCodeUnitOffset`. After the
+    /// function returns, `currentCodeUnitOffset` holds the position at the
+    /// start of the returned `Character`, which is also the end of the
+    /// previous `Character`.
+    ///
+    /// Returns `nil` if at the start of the `UTF8Span`.
+    @lifetime(self: copy self)
+    public mutating func previous() -> Character? {
+      guard currentCodeUnitOffset > 0 else { return nil }
+
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: currentCodeUnitOffset))
+      let (result, newPos) = unsafe _start._decodeCharacter(
+        endingAt: currentCodeUnitOffset,
+        limitedBy: codeUnits.count)
+      self.currentCodeUnitOffset = newPos
+      return result
+    }
+
+    /// Advance `codeUnitOffset` to the end of the current `Character`,
+    /// without constructing it.
+    ///
+    /// Returns the number of `Character`s skipped over, which can be 0
+    /// if at the end of the UTF8Span.
+    @lifetime(self: copy self)
+    public mutating func skipForward() -> Int {
+      guard currentCodeUnitOffset < codeUnits.count else {
+        return 0
+      }
+
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: currentCodeUnitOffset))
+
+      self.currentCodeUnitOffset = unsafe _start._nextCharacterStart(currentCodeUnitOffset, limitedBy: codeUnits.count)
+      return 1
+    }
+
+    /// Advance `codeUnitOffset` to the end of `n` `Characters`, without
+    /// constructing them.
+    ///
+    /// Returns the number of `Character`s skipped over, which can be
+    /// fewer than `n` if at the end of the UTF8Span.
+    @lifetime(self: copy self)
+    public mutating func skipForward(by n: Int) -> Int {
+      var numSkipped = 0
+      while numSkipped < n && skipForward() != 0 {
+        numSkipped += 1
+      }
+
+      return numSkipped
+    }
+
+    /// Move `codeUnitOffset` to the start of the previous `Character`,
+    /// without constructing it.
+    ///
+    /// Returns the number of `Character`s skipped over, which can be 0
+    /// if at the start of the UTF8Span.
+    @lifetime(self: copy self)
+    public mutating func skipBack() -> Int {
+      guard currentCodeUnitOffset > 0 else {
+        return 0
+      }
+
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: currentCodeUnitOffset))
+
+      currentCodeUnitOffset = unsafe _start._previousCharacterStart(currentCodeUnitOffset, limitedBy: codeUnits.count)
+      return 1
+
+    }
+
+    /// Move `codeUnitOffset` to the start of the previous `n` `Character`s,
+    /// without constructing them.
+    ///
+    /// Returns the number of `Character`s skipped over, which can be
+    /// fewer than `n` if at the start of the UTF8Span.
+    @lifetime(self: copy self)
+    public mutating func skipBack(by n: Int) -> Int {
+      var numSkipped = 0
+      while numSkipped < n && skipBack() != 0 {
+        numSkipped += 1
+      }
+
+      return numSkipped
+    }
+
+    /// Reset to the nearest character-aligned position `<= i`.
+    @lifetime(self: copy self)
+    public mutating func reset(roundingBackwardsFrom i: Int) {
+      self.currentCodeUnitOffset = codeUnits._scalarAlignBackwards(i)
+    }
+
+    /// Reset to the nearest character-aligned position `>= i`.
+    @lifetime(self: copy self)
+    public mutating func reset(roundingForwardsFrom i: Int) {
+      self.currentCodeUnitOffset = codeUnits._scalarAlignForwards(i)
+    }
+
+    /// Reset this iterator to `codeUnitOffset`, skipping _all_ safety
+    /// checks.
+    ///
+    /// Note: This is only for very specific, low-level use cases. If
+    /// `codeUnitOffset` is not properly scalar-aligned, this function can
+    /// result in undefined behavior when, e.g., `next()` is called.
+    ///
+    /// If `i` is scalar-aligned, but not `Character`-aligned, you may get
+    /// different results from running `Character` iteration.
+    ///
+    /// For example, this could be used by a regex engine to backtrack to a
+    /// known-valid previous position.
+    ///
+    @unsafe
+    @lifetime(self: copy self)
+    public mutating func reset(toUnchecked codeUnitOffset: Int) {
+      _internalInvariant(codeUnits._isScalarAligned(unchecked: codeUnitOffset))
+      self.currentCodeUnitOffset = codeUnitOffset
+    }
+
+    /// Returns the UTF8Span containing all the content up to the iterator's
+    /// current position.
+    @lifetime(copy self)
+    public func prefix() -> UTF8Span {
+      let slice = codeUnits.span.extracting(0..<currentCodeUnitOffset)
+      return UTF8Span(
+        _uncheckedAssumingValidUTF8: slice,
+        isKnownASCII: codeUnits.isKnownASCII,
+        isKnownNFC: codeUnits.isKnownNFC)
+    }
+
+    /// Returns the UTF8Span containing all the content after the iterator's
+    /// current position.
+    @lifetime(copy self)
+    public func suffix() -> UTF8Span {
+      let slice = codeUnits.span.extracting(currentCodeUnitOffset..<codeUnits.count)
+      return UTF8Span(
+        _uncheckedAssumingValidUTF8: slice,
+        isKnownASCII: codeUnits.isKnownASCII,
+        isKnownNFC: codeUnits.isKnownNFC)
+    }
+  }
+}
+
+
diff --git a/stdlib/public/core/UnicodeBreakProperty.swift b/stdlib/public/core/UnicodeBreakProperty.swift
index c0f97694d6c51..d4e197e87f316 100644
--- a/stdlib/public/core/UnicodeBreakProperty.swift
+++ b/stdlib/public/core/UnicodeBreakProperty.swift
@@ -13,7 +13,7 @@
 import SwiftShims
 
 extension Unicode {
-  internal enum _GraphemeBreakProperty {
+  internal enum _GraphemeBreakProperty: Sendable {
     case any
     case control
     case extend
@@ -86,7 +86,7 @@ extension Unicode {
 }
 
 extension Unicode {
-  internal enum _WordBreakProperty {
+  internal enum _WordBreakProperty: UInt8, Sendable {
     case aLetter
     case any
     case doubleQuote
@@ -105,8 +105,8 @@ extension Unicode {
     case singleQuote
     case wSegSpace
     case zwj
-    
-    init(from scalar: Unicode.Scalar) {
+
+    internal init(from scalar: Unicode.Scalar) {
       switch scalar.value {
       case 0xA ... 0xD,
            0x85,
@@ -122,7 +122,7 @@ extension Unicode {
         self = .regionalIndicator
       default:
         let rawValue = _swift_stdlib_getWordBreakProperty(scalar.value)
-        
+
         switch rawValue {
         case 0:
           self = .extend
diff --git a/stdlib/public/core/UnicodeHelpers.swift b/stdlib/public/core/UnicodeHelpers.swift
index 79f8af7c7f83a..47fde997f9abb 100644
--- a/stdlib/public/core/UnicodeHelpers.swift
+++ b/stdlib/public/core/UnicodeHelpers.swift
@@ -61,7 +61,7 @@ internal func _decodeUTF8(
   return Unicode.Scalar(_unchecked: value)
 }
 
-@inlinable
+@inlinable @inline(__always)
 internal func _decodeScalar(
   _ utf8: UnsafeBufferPointer<UInt8>, startingAt i: Int
 ) -> (Unicode.Scalar, scalarLength: Int) {
@@ -207,7 +207,7 @@ extension _StringGuts {
     }
   }
 
-  @inlinable
+  @inlinable @inline(__always)
   internal func fastUTF8Scalar(startingAt i: Int) -> Unicode.Scalar {
     _internalInvariant(isFastUTF8)
     return unsafe self.withFastUTF8 { unsafe _decodeScalar($0, startingAt: i).0 }
diff --git a/stdlib/public/core/UnicodeSPI.swift b/stdlib/public/core/UnicodeSPI.swift
index 0b4b2f40e29f9..7939f878fd337 100644
--- a/stdlib/public/core/UnicodeSPI.swift
+++ b/stdlib/public/core/UnicodeSPI.swift
@@ -207,35 +207,3 @@ extension Unicode.Scalar.Properties {
     return result
   }
 }
-
-//===----------------------------------------------------------------------===//
-// String Word Breaking
-//===----------------------------------------------------------------------===//
-
-extension String {
-  @_spi(_Unicode)
-  @available(SwiftStdlib 5.7, *)
-  public func _wordIndex(after i: String.Index) -> String.Index {
-    let i = _guts.validateWordIndex(i)
-
-    let next = _guts.nextWordIndex(startingAt: i._encodedOffset)
-    return String.Index(_encodedOffset: next)
-  }
-
-  @_spi(_Unicode)
-  @available(SwiftStdlib 5.7, *)
-  public func _wordIndex(before i: String.Index) -> String.Index {
-    let i = _guts.validateInclusiveWordIndex(i)
-
-    _precondition(i > startIndex, "String index is out of bounds")
-
-    let previous = _guts.previousWordIndex(endingAt: i._encodedOffset)
-    return String.Index(_encodedOffset: previous)
-  }
-
-  @_spi(_Unicode)
-  @available(SwiftStdlib 5.7, *)
-  public func _nearestWordIndex(atOrBelow i: String.Index) -> String.Index {
-    _guts.validateInclusiveWordIndex(i)
-  }
-}
diff --git a/stdlib/public/core/UnsafeBufferPointer.swift.gyb b/stdlib/public/core/UnsafeBufferPointer.swift.gyb
index ca385ef259525..b37c7d0b5e4aa 100644
--- a/stdlib/public/core/UnsafeBufferPointer.swift.gyb
+++ b/stdlib/public/core/UnsafeBufferPointer.swift.gyb
@@ -126,7 +126,7 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
   ///
   /// If the `baseAddress` of this buffer is `nil`, the count is zero. However,
   /// a buffer can have a `count` of zero even with a non-`nil` base address.
-  @inlinable
+  @_transparent
   @_preInverseGenerics
   @safe
   public var baseAddress: Unsafe${Mutable}Pointer<Element>? {
@@ -212,7 +212,7 @@ extension Unsafe${Mutable}BufferPointer: @unsafe Sequence {
     return (unsafe Iterator(_position: s + n, _end: s + count), n)
   }
 
-  @inlinable
+  @inlinable @_transparent
   @safe
   public func withContiguousStorageIfAvailable<R>(
     _ body: (UnsafeBufferPointer<Element>) throws -> R
@@ -240,7 +240,7 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
   ///
   /// The `startIndex` property of an `Unsafe${Mutable}BufferPointer` instance
   /// is always zero.
-  @inlinable
+  @_transparent
   @_preInverseGenerics
   @safe
   public var startIndex: Int { 0 }
@@ -250,20 +250,20 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
   ///
   /// The `endIndex` property of an `Unsafe${Mutable}BufferPointer` instance is
   /// always identical to `count`.
-  @inlinable
+  @_transparent
   @_preInverseGenerics
   @safe
   public var endIndex: Int { count }
 
-  @inlinable
-  @safe
+  @_transparent
   @_preInverseGenerics
+  @safe
   public var indices: Range<Int> {
     // Not checked because init forbids negative count.
     unsafe Range(uncheckedBounds: (0, count))
   }
 
-  @inlinable
+  @_transparent
   @_preInverseGenerics
   public func index(after i: Int) -> Int {
     // NOTE: this is a manual specialization of index movement for a Strideable
@@ -281,7 +281,7 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
     return result.partialValue
   }
 
-  @inlinable
+  @_transparent
   @_preInverseGenerics
   public func formIndex(after i: inout Int) {
     // NOTE: this is a manual specialization of index movement for a Strideable
@@ -295,7 +295,7 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
     i = result.partialValue
   }
 
-  @inlinable
+  @_transparent
   @_preInverseGenerics
   public func index(before i: Int) -> Int {
     // NOTE: this is a manual specialization of index movement for a Strideable
@@ -309,7 +309,7 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
     return result.partialValue
   }
 
-  @inlinable
+  @_transparent
   @_preInverseGenerics
   public func formIndex(before i: inout Int) {
     // NOTE: this is a manual specialization of index movement for a Strideable
@@ -323,7 +323,7 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
     i = result.partialValue
   }
 
-  @inlinable
+  @_transparent
   @_preInverseGenerics
   public func index(_ i: Int, offsetBy n: Int) -> Int {
     // NOTE: this is a manual specialization of index movement for a Strideable
@@ -572,17 +572,32 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
   public func extracting(_ bounds: UnboundedRange) -> Self {
     unsafe self
   }
+}
 
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
   @unsafe
-  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
   public var span: Span<Element> {
     @lifetime(borrow self)
-    @_alwaysEmitIntoClient
+    @_transparent
     get {
-      let span = unsafe Span(_unsafeElements: self)
-      return unsafe _overrideLifetime(span, borrowing: self)
+      unsafe Span(_unsafeElements: self)
     }
   }
+%if Mutable:
+
+  @unsafe
+  @_alwaysEmitIntoClient
+  public var mutableSpan: MutableSpan<Element> {
+    @lifetime(borrow self)
+    @_transparent
+    get {
+      unsafe MutableSpan(_unsafeElements: self)
+    }
+  }
+%end
 }
 
 extension Unsafe${Mutable}BufferPointer {
@@ -765,7 +780,7 @@ extension Unsafe${Mutable}BufferPointer:
     return try unsafe body(&self)
   }
 
-  @inlinable
+  @inlinable @_transparent
   @safe
   public mutating func withContiguousMutableStorageIfAvailable<R>(
     _ body: (inout UnsafeMutableBufferPointer<Element>) throws -> R
@@ -780,6 +795,15 @@ extension Unsafe${Mutable}BufferPointer:
 %  end
 }
 
+extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
+  @safe
+  @_alwaysEmitIntoClient
+  public func _isWellAligned() -> Bool {
+    guard let p = baseAddress else { return true }
+    return p._isWellAligned()
+  }
+}
+
 extension Unsafe${Mutable}BufferPointer {
 %  if not Mutable:
   /// Creates a buffer over the same memory as the given buffer slice.
@@ -801,7 +825,7 @@ extension Unsafe${Mutable}BufferPointer {
   /// - `rebased.count == slice.count`
   ///
   /// - Parameter slice: The buffer slice to rebase.
-  @inlinable // unsafe-performance
+  @inlinable @_transparent // unsafe-performance
   public init(rebasing slice: Slice<UnsafeBufferPointer<Element>>) {
     // NOTE: `Slice` does not guarantee that its start/end indices are valid
     // in `base` -- it merely ensures that `startIndex <= endIndex`.
@@ -840,7 +864,7 @@ extension Unsafe${Mutable}BufferPointer {
   /// - `rebased.count == slice.count`
   ///
   /// - Parameter slice: The buffer slice to rebase.
-  @inlinable // unsafe-performance
+  @inlinable @_transparent // unsafe-performance
   public init(rebasing slice: Slice<UnsafeMutableBufferPointer<Element>>) {
     let base = unsafe slice.base.baseAddress?.advanced(by: slice.startIndex)
     let count = unsafe slice.endIndex &- slice.startIndex
@@ -969,7 +993,7 @@ extension UnsafeMutableBufferPointer {
   ///     initialize the buffer's storage.
   /// - Returns: The index one past the last element of the buffer initialized
   ///     by this function.
-  @_alwaysEmitIntoClient
+  @_alwaysEmitIntoClient @_transparent 
   public func initialize(
     fromContentsOf source: some Collection<Element>
   ) -> Index {
@@ -1197,7 +1221,7 @@ extension UnsafeMutableBufferPointer {
 }
 
 extension UnsafeMutableBufferPointer where Element: ~Copyable {
-  /// Updates this buffer's initialized memory initialized memory by moving
+  /// Updates this buffer's initialized memory by moving
   /// every element from the source buffer, leaving the source memory
   /// uninitialized.
   ///
@@ -1300,7 +1324,7 @@ extension UnsafeMutableBufferPointer where Element: ~Copyable {
   ///   - index: The index of the element to initialize
   @_alwaysEmitIntoClient
   public func initializeElement(at index: Index, to value: consuming Element) {
-    _debugPrecondition(unsafe startIndex <= index && index < endIndex)
+    _debugPrecondition(startIndex <= index && index < endIndex)
     let p = unsafe baseAddress._unsafelyUnwrappedUnchecked.advanced(by: index)
     unsafe p.initialize(to: value)
   }
@@ -1317,7 +1341,7 @@ extension UnsafeMutableBufferPointer where Element: ~Copyable {
   /// - Returns: The instance referenced by this index in this buffer.
   @_alwaysEmitIntoClient
   public func moveElement(from index: Index) -> Element {
-    _debugPrecondition(unsafe startIndex <= index && index < endIndex)
+    _debugPrecondition(startIndex <= index && index < endIndex)
     return unsafe baseAddress._unsafelyUnwrappedUnchecked.advanced(by: index).move()
   }
 
@@ -1331,7 +1355,7 @@ extension UnsafeMutableBufferPointer where Element: ~Copyable {
   ///   - index: The index of the buffer element to deinitialize.
   @_alwaysEmitIntoClient
   public func deinitializeElement(at index: Index) {
-    _debugPrecondition(unsafe startIndex <= index && index < endIndex)
+    _debugPrecondition(startIndex <= index && index < endIndex)
     let p = unsafe baseAddress._unsafelyUnwrappedUnchecked.advanced(by: index)
     unsafe p.deinitialize(count: 1)
   }
@@ -1394,7 +1418,7 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
   ///     method.
   ///   - buffer: The buffer temporarily bound to `T`.
   /// - Returns: The return value, if any, of the `body` closure parameter.
-  @_alwaysEmitIntoClient
+  @_alwaysEmitIntoClient @_transparent
   public func withMemoryRebound<T: ~Copyable, E: Error, Result: ~Copyable>(
     to type: T.Type,
     _ body: (_ buffer: ${Self}<T>) throws(E) -> Result
diff --git a/stdlib/public/core/UnsafeBufferPointerSlice.swift b/stdlib/public/core/UnsafeBufferPointerSlice.swift
index 189f9e7923420..5aefd82750f9a 100644
--- a/stdlib/public/core/UnsafeBufferPointerSlice.swift
+++ b/stdlib/public/core/UnsafeBufferPointerSlice.swift
@@ -949,7 +949,7 @@ extension Slice {
     return unsafe startIndex.advanced(by: distance)
   }
 
-  /// Updates this buffer slice's initialized memory initialized memory by
+  /// Updates this buffer slice's initialized memory by
   /// moving every element from the source buffer,
   /// leaving the source memory uninitialized.
   ///
diff --git a/stdlib/public/core/UnsafePointer.swift b/stdlib/public/core/UnsafePointer.swift
index db53ea3a0e57b..a4e8b9558b9f1 100644
--- a/stdlib/public/core/UnsafePointer.swift
+++ b/stdlib/public/core/UnsafePointer.swift
@@ -469,6 +469,13 @@ extension UnsafePointer where Pointee: ~Copyable {
   }
 }
 
+extension UnsafePointer where Pointee: ~Copyable {
+  @safe
+  @_alwaysEmitIntoClient
+  public func _isWellAligned() -> Bool {
+    (Int(bitPattern: self) & (MemoryLayout<Pointee>.alignment &- 1)) == 0
+  }
+}
 
 /// A pointer for accessing and manipulating data of a
 /// specific type.
@@ -1382,3 +1389,11 @@ extension UnsafeMutablePointer where Pointee: ~Copyable {
     )._unsafelyUnwrappedUnchecked
   }
 }
+
+extension UnsafeMutablePointer where Pointee: ~Copyable {
+  @safe
+  @_alwaysEmitIntoClient
+  public func _isWellAligned() -> Bool {
+    (Int(bitPattern: self) & (MemoryLayout<Pointee>.alignment &- 1)) == 0
+  }
+}
diff --git a/stdlib/public/core/UnsafeRawBufferPointer.swift.gyb b/stdlib/public/core/UnsafeRawBufferPointer.swift.gyb
index 2ee50c1b77af2..fc6e9e86b11bc 100644
--- a/stdlib/public/core/UnsafeRawBufferPointer.swift.gyb
+++ b/stdlib/public/core/UnsafeRawBufferPointer.swift.gyb
@@ -100,6 +100,17 @@ public struct Unsafe${Mutable}RawBufferPointer {
   @usableFromInline
   internal let _position, _end: Unsafe${Mutable}RawPointer?
 
+  // This works around _debugPrecondition() impacting the performance of
+  // optimized code. (rdar://72246338)
+  @_alwaysEmitIntoClient @_transparent
+  internal init(
+    @_nonEphemeral _uncheckedStart start: Unsafe${Mutable}RawPointer?,
+    count: Int
+  ) {
+    unsafe _position = start
+    unsafe _end = start.map { unsafe $0 + _assumeNonNegative(count) }
+  }
+
   /// Creates a buffer over the specified number of contiguous bytes starting
   /// at the given pointer.
   ///
@@ -109,16 +120,21 @@ public struct Unsafe${Mutable}RawBufferPointer {
   ///     for a non-`nil` `start`.
   ///   - count: The number of bytes to include in the buffer. `count` must not
   ///     be negative.
-  @inlinable
+  @inlinable @_transparent
   public init(
     @_nonEphemeral start: Unsafe${Mutable}RawPointer?, count: Int
   ) {
     _debugPrecondition(count >= 0, "${Self} with negative count")
     _debugPrecondition(unsafe count == 0 || start != nil,
       "${Self} has a nil start and nonzero count")
+    unsafe self.init(_uncheckedStart: start, count: count)
+  }
 
-    unsafe _position = start
-    unsafe _end = start.map { unsafe $0 + _assumeNonNegative(count) }
+  @safe @_transparent
+  @_alwaysEmitIntoClient
+  public init(_empty: ()) {
+    unsafe _position = nil
+    unsafe _end = nil
   }
 }
 
@@ -134,7 +150,7 @@ extension UnsafeRawBufferPointer {
     @usableFromInline
     internal var _position, _end: UnsafeRawPointer?
 
-    @inlinable
+    @inlinable @_transparent
     internal init(_position: UnsafeRawPointer?, _end: UnsafeRawPointer?) {
       unsafe self._position = _position
       unsafe self._end = _end
@@ -605,7 +621,7 @@ extension Unsafe${Mutable}RawBufferPointer {
   /// Creates a new buffer over the same memory as the given buffer.
   ///
   /// - Parameter bytes: The buffer to convert.
-  @inlinable
+  @inlinable @_transparent
   @safe
   public init(_ bytes: UnsafeMutableRawBufferPointer) {
     unsafe self.init(start: bytes.baseAddress, count: bytes.count)
@@ -615,7 +631,7 @@ extension Unsafe${Mutable}RawBufferPointer {
   /// Creates a new mutable buffer over the same memory as the given buffer.
   ///
   /// - Parameter bytes: The buffer to convert.
-  @inlinable
+  @inlinable @_transparent
   public init(mutating bytes: UnsafeRawBufferPointer) {
     unsafe self.init(start: UnsafeMutableRawPointer(mutating: bytes.baseAddress),
       count: bytes.count)
@@ -624,7 +640,7 @@ extension Unsafe${Mutable}RawBufferPointer {
   /// Creates a new buffer over the same memory as the given buffer.
   ///
   /// - Parameter bytes: The buffer to convert.
-  @inlinable
+  @inlinable @_transparent
   @safe
   public init(_ bytes: UnsafeRawBufferPointer) {
     unsafe self.init(start: bytes.baseAddress, count: bytes.count)
@@ -635,7 +651,7 @@ extension Unsafe${Mutable}RawBufferPointer {
   ///
   /// - Parameter buffer: The typed buffer to convert to a raw buffer. The
   ///   buffer's type `T` must be a trivial type.
-  @inlinable
+  @inlinable @_transparent
   @_preInverseGenerics
   @safe
   public init<T: ~Copyable>(_ buffer: UnsafeMutableBufferPointer<T>) {
@@ -648,7 +664,7 @@ extension Unsafe${Mutable}RawBufferPointer {
   ///
   /// - Parameter buffer: The typed buffer to convert to a raw buffer. The
   ///   buffer's type `T` must be a trivial type.
-  @inlinable
+  @inlinable @_transparent
   @_preInverseGenerics
   @safe
   public init<T: ~Copyable>(_ buffer: UnsafeBufferPointer<T>) {
@@ -678,7 +694,7 @@ extension Unsafe${Mutable}RawBufferPointer {
   /// - `rebased.count == slice.count`
   ///
   /// - Parameter slice: The raw buffer slice to rebase.
-  @inlinable
+  @inlinable @_transparent
   public init(rebasing slice: Slice<UnsafeRawBufferPointer>) {
     // NOTE: `Slice` does not guarantee that its start/end indices are valid
     // in `base` -- it merely ensures that `startIndex <= endIndex`.
@@ -717,7 +733,7 @@ extension Unsafe${Mutable}RawBufferPointer {
   /// - `rebased.count == slice.count`
   ///
   /// - Parameter slice: The raw buffer slice to rebase.
-  @inlinable
+  @inlinable @_transparent
   public init(rebasing slice: Slice<UnsafeMutableRawBufferPointer>) {
     let base = unsafe slice.base.baseAddress?.advanced(by: slice.startIndex)
     let count = unsafe slice.endIndex &- slice.startIndex
@@ -1094,7 +1110,7 @@ extension Unsafe${Mutable}RawBufferPointer {
   ///     the return value for the `withMemoryRebound(to:capacity:_:)` method.
   ///   - buffer: The buffer temporarily bound to instances of `T`.
   /// - Returns: The return value, if any, of the `body` closure parameter.
-  @_alwaysEmitIntoClient
+  @_alwaysEmitIntoClient @_transparent
   public func withMemoryRebound<T: ~Copyable, E: Error, Result: ~Copyable>(
     to type: T.Type,
     _ body: (_ buffer: Unsafe${Mutable}BufferPointer<T>) throws(E) -> Result
@@ -1131,7 +1147,7 @@ extension Unsafe${Mutable}RawBufferPointer {
   ///
   /// - Parameter to: The type `T` that the memory has already been bound to.
   /// - Returns: A typed pointer to the same memory as this raw pointer.
-  @_alwaysEmitIntoClient
+  @_alwaysEmitIntoClient @_transparent
   public func assumingMemoryBound<T: ~Copyable>(
     to: T.Type
   ) -> Unsafe${Mutable}BufferPointer<T> {
@@ -1147,6 +1163,7 @@ extension Unsafe${Mutable}RawBufferPointer {
 
 %  if Mutable:
   @_alwaysEmitIntoClient
+  @_transparent
   public func withContiguousMutableStorageIfAvailable<R>(
     _ body: (inout UnsafeMutableBufferPointer<Element>) throws -> R
   ) rethrows -> R? {
@@ -1164,6 +1181,7 @@ extension Unsafe${Mutable}RawBufferPointer {
 
 %  end
   @_alwaysEmitIntoClient
+  @_transparent
   public func withContiguousStorageIfAvailable<R>(
     _ body: (UnsafeBufferPointer<Element>) throws -> R
   ) rethrows -> R? {
@@ -1171,17 +1189,32 @@ extension Unsafe${Mutable}RawBufferPointer {
       try unsafe body(${ 'UnsafeBufferPointer<Element>($0)' if Mutable else '$0' })
     }
   }
-
+}
+  
+@available(SwiftCompatibilitySpan 5.0, *)
+@_originallyDefinedIn(module: "Swift;CompatibilitySpan", SwiftCompatibilitySpan 6.2)
+extension Unsafe${Mutable}RawBufferPointer {
   @unsafe
-  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
   public var bytes: RawSpan {
     @lifetime(borrow self)
-    @_alwaysEmitIntoClient
+    @_transparent
     get {
-      let span = unsafe RawSpan(_unsafeBytes: self)
-      return unsafe _overrideLifetime(span, borrowing: self)
+      unsafe RawSpan(_unsafeBytes: self)
     }
   }
+%  if Mutable:
+
+  @unsafe
+  @_alwaysEmitIntoClient
+  public var mutableBytes: MutableRawSpan {
+    @lifetime(borrow self)
+    @_transparent
+    get {
+      unsafe MutableRawSpan(_unsafeBytes: self)
+    }
+  }
+% end
 }
 
 @_unavailableInEmbedded
@@ -1245,6 +1278,7 @@ public func withUnsafeMutableBytes<T: ~Copyable, E: Error, Result: ~Copyable>(
   return try unsafe body(unsafe .init(start: pointer, count: MemoryLayout<T>.size))
 }
 
+#if !$Embedded
 /// ABI: Historical withUnsafeMutableBytes(of:_:) rethrows,
 /// expressed as "throws", which is ABI-compatible with "rethrows".
 @_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@@ -1259,6 +1293,7 @@ func __abi_se0413_withUnsafeMutableBytes<T, Result>(
         start: $0, count: MemoryLayout<T>.size))
   }
 }
+#endif
 
 /// Invokes the given closure with a buffer pointer covering the raw bytes of
 /// the given argument.
@@ -1312,6 +1347,7 @@ public func withUnsafeBytes<T: ~Copyable, E: Error, Result: ~Copyable>(
   return try unsafe body(unsafe .init(start: address, count: MemoryLayout<T>.size))
 }
 
+#if !$Embedded
 /// ABI: Historical withUnsafeBytes(of:_:) rethrows,
 /// expressed as "throws", which is ABI-compatible with "rethrows".
 @_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@@ -1325,6 +1361,7 @@ func __abi_se0413_withUnsafeBytes<T, Result>(
     try unsafe body(unsafe UnsafeRawBufferPointer(start: $0, count: MemoryLayout<T>.size))
   }
 }
+#endif
 
 /// Invokes the given closure with a buffer pointer covering the raw bytes of
 /// the given argument.
@@ -1376,6 +1413,7 @@ public func withUnsafeBytes<
   return try unsafe body(unsafe .init(start: addr, count: MemoryLayout<T>.size))
 }
 
+#if !$Embedded
 /// ABI: Historical withUnsafeBytes(of:_:) rethrows,
 /// expressed as "throws", which is ABI-compatible with "rethrows".
 @_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@@ -1389,6 +1427,7 @@ func __abi_se0413_withUnsafeBytes<T, Result>(
   let buffer = unsafe UnsafeRawBufferPointer(start: addr, count: MemoryLayout<T>.size)
   return try unsafe body(buffer)
 }
+#endif
 
 /// Invokes the given closure with a buffer pointer covering the raw bytes of
 /// the given argument.
diff --git a/stdlib/public/core/VarArgs.swift b/stdlib/public/core/VarArgs.swift
index c520741096b5b..0bef714fa6d6e 100644
--- a/stdlib/public/core/VarArgs.swift
+++ b/stdlib/public/core/VarArgs.swift
@@ -1,3 +1,4 @@
+
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the Swift.org open source project
@@ -567,21 +568,21 @@ final internal class __VaListBuilder {
   @inlinable // c-abi
   internal func va_list() -> CVaListPointer {
     #if arch(x86_64) || arch(s390x)
-      header.reg_save_area = storage._baseAddress
+      unsafe header.reg_save_area = storage._baseAddress
       unsafe header.overflow_arg_area
         = storage._baseAddress + _registerSaveWords
       return unsafe CVaListPointer(
                _fromUnsafeMutablePointer: UnsafeMutableRawPointer(
                  Builtin.addressof(&self.header)))
     #elseif arch(arm64)
-      let vr_top = storage._baseAddress + (_fpRegisterWords * _countFPRegisters)
-      let gr_top = vr_top + _countGPRegisters
-
-      return CVaListPointer(__stack: gr_top,
-                            __gr_top: gr_top,
-                            __vr_top: vr_top,
-                            __gr_off: -64,
-                            __vr_off: -128)
+      let vr_top = unsafe storage._baseAddress + (_fpRegisterWords * _countFPRegisters)
+      let gr_top = unsafe vr_top + _countGPRegisters
+
+      return unsafe CVaListPointer(__stack: gr_top,
+                                   __gr_top: gr_top,
+                                   __vr_top: vr_top,
+                                   __gr_off: -64,
+                                   __vr_off: -128)
     #endif
   }
 }
@@ -609,7 +610,7 @@ final internal class __VaListBuilder {
     // We may need to retain an object that provides a pointer value.
     if let obj = arg as? _CVarArgObject {
       arg = obj._cVarArgObject
-      retainer.append(arg)
+      unsafe retainer.append(arg)
     }
 #endif
 
@@ -621,10 +622,10 @@ final internal class __VaListBuilder {
 #if (arch(arm) && !os(iOS)) || arch(arm64_32) || arch(wasm32)
     if let arg = arg as? _CVarArgAligned {
       let alignmentInWords = arg._cVarArgAlignment / MemoryLayout<Int>.size
-      let misalignmentInWords = count % alignmentInWords
+      let misalignmentInWords = unsafe count % alignmentInWords
       if misalignmentInWords != 0 {
         let paddingInWords = alignmentInWords - misalignmentInWords
-        appendWords([Int](repeating: -1, count: paddingInWords))
+        unsafe appendWords([Int](repeating: -1, count: paddingInWords))
       }
     }
 #endif
diff --git a/stdlib/public/libexec/swift-backtrace/CMakeLists.txt b/stdlib/public/libexec/swift-backtrace/CMakeLists.txt
index 20f6048a1ea8f..0c9c45b0b8fda 100644
--- a/stdlib/public/libexec/swift-backtrace/CMakeLists.txt
+++ b/stdlib/public/libexec/swift-backtrace/CMakeLists.txt
@@ -6,12 +6,20 @@ set(glibc)
 set(musl)
 
 if(SWIFT_BUILD_SDK_OVERLAY)
-  set(darwin Darwin)
   set(wincrt_sdk CRT WinSDK)
   set(glibc Glibc)
   set(musl Musl)
 endif()
 
+if((SWIFT_BUILD_CLANG_OVERLAYS
+    OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
+   AND (NOT DEFINED SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT
+        OR NOT SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT))
+  # This library imports Darwin from the SDK, which re-exports
+  # _Builtin_float which is part of this build.
+  list(APPEND darwin _Builtin_float)
+endif()
+
 # Similarly, we only want the Runtime dependency if we're building
 # with the stdlib.
 set(runtime)
diff --git a/stdlib/public/runtime/Backtrace.cpp b/stdlib/public/runtime/Backtrace.cpp
index f4b835898b508..18bad7bf620b6 100644
--- a/stdlib/public/runtime/Backtrace.cpp
+++ b/stdlib/public/runtime/Backtrace.cpp
@@ -902,7 +902,11 @@ _swift_backtraceSetupEnvironment()
 
     size_t nameLen = std::strlen(name);
     size_t valueLen = std::strlen(value);
-    size_t totalLen = nameLen + 1 + valueLen + 1;
+    size_t totalLen;
+
+    if (__builtin_add_overflow(nameLen + 1, valueLen + 1, &totalLen)) {
+      break;
+    }
 
     if (remaining > totalLen) {
       std::memcpy(penv, name, nameLen);
diff --git a/stdlib/public/runtime/Casting.cpp b/stdlib/public/runtime/Casting.cpp
index f495c03d0c0e5..254fdcc10669e 100644
--- a/stdlib/public/runtime/Casting.cpp
+++ b/stdlib/public/runtime/Casting.cpp
@@ -1436,10 +1436,31 @@ extern "C" const _ObjectiveCBridgeableWitnessTable BRIDGING_CONFORMANCE_SYM;
 /// Nominal type descriptor for Swift.String.
 extern "C" const StructDescriptor NOMINAL_TYPE_DESCR_SYM(SS);
 
+struct ObjCBridgeWitnessCacheEntry {
+  const Metadata *metadata;
+  const _ObjectiveCBridgeableWitnessTable *witness;
+};
+
+// String is so important that we cache it permanently, so we don't want to
+// pollute this temporary cache with the String entry
+static const _ObjectiveCBridgeableWitnessTable *
+swift_conformsToObjectiveCBridgeableNoCache(const Metadata *T) {
+  auto w = swift_conformsToProtocolCommon(
+         T, &PROTOCOL_DESCR_SYM(s21_ObjectiveCBridgeable));
+  return reinterpret_cast<const _ObjectiveCBridgeableWitnessTable *>(w);
+}
+
 static const _ObjectiveCBridgeableWitnessTable *
 swift_conformsToObjectiveCBridgeable(const Metadata *T) {
-  return reinterpret_cast<const _ObjectiveCBridgeableWitnessTable *>
-    (swift_conformsToProtocolCommon(T, &PROTOCOL_DESCR_SYM(s21_ObjectiveCBridgeable)));
+  static std::atomic<ObjCBridgeWitnessCacheEntry> _objcBridgeWitnessCache = {};
+  auto cached = _objcBridgeWitnessCache.load(SWIFT_MEMORY_ORDER_CONSUME);
+  if (cached.metadata == T) {
+    return cached.witness;
+  }
+  cached.witness = swift_conformsToObjectiveCBridgeableNoCache(T);
+  cached.metadata = T;
+  _objcBridgeWitnessCache.store(cached, std::memory_order_release);
+  return cached.witness;
 }
 
 static const _ObjectiveCBridgeableWitnessTable *
@@ -1451,7 +1472,7 @@ findBridgeWitness(const Metadata *T) {
   if (T->getKind() == MetadataKind::Struct) {
     auto structDescription = cast<StructMetadata>(T)->Description;
     if (structDescription == &NOMINAL_TYPE_DESCR_SYM(SS)) {
-      static auto *Swift_String_ObjectiveCBridgeable = swift_conformsToObjectiveCBridgeable(T);
+      static auto *Swift_String_ObjectiveCBridgeable = swift_conformsToObjectiveCBridgeableNoCache(T);
       return Swift_String_ObjectiveCBridgeable;
     }
   }
diff --git a/stdlib/public/runtime/CrashHandlerLinux.cpp b/stdlib/public/runtime/CrashHandlerLinux.cpp
index 477d68bbf12b4..970b2cb3af3c5 100644
--- a/stdlib/public/runtime/CrashHandlerLinux.cpp
+++ b/stdlib/public/runtime/CrashHandlerLinux.cpp
@@ -49,6 +49,15 @@
 #include <string.h>
 #include <unistd.h>
 
+#define DEBUG_MEMSERVER 0
+
+#if DEBUG_MEMSERVER
+#include <stdio.h>
+#define memserver_error(x) perror(x)
+#else
+#define memserver_error(x)
+#endif
+
 #include "swift/Runtime/Backtrace.h"
 
 #include <cstring>
@@ -86,8 +95,8 @@ ssize_t safe_read(int fd, void *buf, size_t len) {
     ssize_t ret;
     do {
       ret = read(fd, buf, len);
-    } while (ret < 0 && errno == EINTR);
-    if (ret < 0)
+    } while (ret <= 0 && errno == EINTR);
+    if (ret <= 0)
       return ret;
     total += ret;
     ptr += ret;
@@ -106,8 +115,8 @@ ssize_t safe_write(int fd, const void *buf, size_t len) {
     ssize_t ret;
     do {
       ret = write(fd, buf, len);
-    } while (ret < 0 && errno == EINTR);
-    if (ret < 0)
+    } while (ret <= 0 && errno == EINTR);
+    if (ret <= 0)
       return ret;
     total += ret;
     ptr += ret;
@@ -646,7 +655,6 @@ wait_paused(uint32_t expected, const struct timespec *timeout)
 char memserver_stack[4096] __attribute__((aligned(SWIFT_PAGE_SIZE)));
 char memserver_buffer[4096];
 int memserver_fd;
-bool memserver_has_ptrace;
 sigjmp_buf memserver_fault_buf;
 pid_t memserver_pid;
 
@@ -657,20 +665,28 @@ memserver_start()
   int fds[2];
 
   ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
-  if (ret < 0)
+  if (ret < 0) {
+    memserver_error("memserver_start: socketpair failed");
     return ret;
+  }
 
   memserver_fd = fds[0];
   ret = clone(memserver_entry, memserver_stack + sizeof(memserver_stack),
 #if MEMSERVER_USE_PROCESS
               0,
 #else
-              CLONE_THREAD | CLONE_VM | CLONE_FILES
-              | CLONE_FS | CLONE_IO | CLONE_SIGHAND,
+              #ifndef __musl__
+              // Can't use CLONE_THREAD on musl because the clone() function
+              // there returns EINVAL if we do.
+              CLONE_THREAD | CLONE_SIGHAND |
+              #endif
+              CLONE_VM | CLONE_FILES | CLONE_FS | CLONE_IO,
 #endif
               NULL);
-  if (ret < 0)
+  if (ret < 0) {
+    memserver_error("memserver_start: clone failed");
     return ret;
+  }
 
 #if MEMSERVER_USE_PROCESS
   memserver_pid = ret;
@@ -695,21 +711,18 @@ memserver_fault(int sig) {
 
 ssize_t __attribute__((noinline))
 memserver_read(void *to, const void *from, size_t len) {
-  if (memserver_has_ptrace) {
-// This won't run for older Android APIs anyway, but it can't be compiled
-// either, as process_vm_readv() isn't available.
-#if !(defined(__ANDROID_API__) && __ANDROID_API__ < 23)
-    struct iovec local = { to, len };
-    struct iovec remote = { const_cast<void *>(from), len };
-    return process_vm_readv(memserver_pid, &local, 1, &remote, 1, 0);
-#endif
+  /* Earlier versions of this code tried to use process_vm_readv() if they
+     detected that CAP_SYS_PTRACE was enabled.  This is theoretically
+     slightly safer than using signals and memcpy(), but in practice it
+     turns out that some kernels don't support process_vm_readv() even
+     when CAP_SYS_PTRACE is enabled.
+
+     It seems simpler just to use the signal handlers instead. */
+  if (!sigsetjmp(memserver_fault_buf, 1)) {
+    memcpy(to, from, len);
+    return len;
   } else {
-    if (!sigsetjmp(memserver_fault_buf, 1)) {
-      memcpy(to, from, len);
-      return len;
-    } else {
-      return -1;
-    }
+    return -1;
   }
 }
 
@@ -718,33 +731,26 @@ memserver_entry(void *dummy __attribute__((unused))) {
   int fd = memserver_fd;
   int result = 1;
 
-#if MEMSERVER_USE_PROCESS
+#if MEMSERVER_USE_PROCESS || defined(__musl__)
   prctl(PR_SET_NAME, "[backtrace]");
 #endif
 
-// process_vm_readv() is not available for older Android APIs.
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 23
-  memserver_has_ptrace = false;
-#else
-  memserver_has_ptrace = !!prctl(PR_CAPBSET_READ, CAP_SYS_PTRACE);
-#endif
-
-  if (!memserver_has_ptrace) {
-    struct sigaction sa;
-    sigfillset(&sa.sa_mask);
-    sa.sa_handler = memserver_fault;
-    sa.sa_flags = SA_NODEFER;
-    sigaction(SIGSEGV, &sa, NULL);
-    sigaction(SIGBUS, &sa, NULL);
-  }
+  struct sigaction sa;
+  sigfillset(&sa.sa_mask);
+  sa.sa_handler = memserver_fault;
+  sa.sa_flags = SA_NODEFER;
+  sigaction(SIGSEGV, &sa, NULL);
+  sigaction(SIGBUS, &sa, NULL);
 
   for (;;) {
     struct memserver_req req;
     ssize_t ret;
 
     ret = safe_read(fd, &req, sizeof(req));
-    if (ret != sizeof(req))
+    if (ret != sizeof(req)) {
+      memserver_error("memserver: terminating because safe_read() returned wrong size");
       break;
+    }
 
     uint64_t addr = req.addr;
     uint64_t bytes = req.len;
@@ -761,15 +767,19 @@ memserver_entry(void *dummy __attribute__((unused))) {
       resp.len = ret;
 
       ret = safe_write(fd, &resp, sizeof(resp));
-      if (ret != sizeof(resp))
+      if (ret != sizeof(resp)) {
+        memserver_error("memserver: terminating because safe_write() failed");
         goto fail;
+      }
 
       if (resp.len < 0)
         break;
 
       ret = safe_write(fd, memserver_buffer, resp.len);
-      if (ret != resp.len)
+      if (ret != resp.len) {
+        memserver_error("memserver: terminating because safe_write() failed (2)");
         goto fail;
+      }
 
       addr += resp.len;
       bytes -= resp.len;
diff --git a/stdlib/public/runtime/Demangle.cpp b/stdlib/public/runtime/Demangle.cpp
index 0befba2969756..9fd0edd57977b 100644
--- a/stdlib/public/runtime/Demangle.cpp
+++ b/stdlib/public/runtime/Demangle.cpp
@@ -465,6 +465,69 @@ _buildDemanglingForNominalType(const Metadata *type, Demangle::Demangler &Dem) {
   return _buildDemanglingForContext(description, demangledGenerics, Dem);
 }
 
+static Demangle::NodePointer
+_replaceGeneralizationArg(Demangle::NodePointer type,
+                          SubstGenericParametersFromMetadata substitutions,
+                          Demangle::Demangler &Dem) {
+  assert(type->getKind() == Node::Kind::Type);
+  auto genericParam = type->getChild(0);
+
+  if (genericParam->getKind() != Node::Kind::DependentGenericParamType)
+    return type;
+
+  auto depth = genericParam->getChild(0)->getIndex();
+  auto index = genericParam->getChild(1)->getIndex();
+
+  auto arg = substitutions.getMetadata(depth, index);
+  assert(arg.isMetadata());
+  return _swift_buildDemanglingForMetadata(arg.getMetadata(), Dem);
+}
+
+static Demangle::NodePointer
+_buildDemanglingForExtendedExistential(const Metadata *type,
+                                       Demangle::Demangler &Dem) {
+  auto ee = cast<ExtendedExistentialTypeMetadata>(type);
+
+  auto demangledExistential = Dem.demangleType(ee->Shape->ExistentialType.get(),
+                                               ResolveToDemanglingForContext(Dem));
+
+  if (!ee->Shape->hasGeneralizationSignature())
+    return demangledExistential;
+
+  SubstGenericParametersFromMetadata substitutions(ee->Shape,
+                                              ee->getGeneralizationArguments());
+
+  // Dig out the requirement list.
+  auto constrainedExistential = demangledExistential->getChild(0);
+  assert(constrainedExistential->getKind() == Node::Kind::ConstrainedExistential);
+  auto reqList = constrainedExistential->getChild(1);
+  assert(reqList->getKind() == Node::Kind::ConstrainedExistentialRequirementList);
+
+  auto newReqList = Dem.createNode(Node::Kind::ConstrainedExistentialRequirementList);
+
+  for (auto req : *reqList) {
+    // Currently, the only requirements that can create generalization arguments
+    // are same types.
+    if (req->getKind() != Node::Kind::DependentGenericSameTypeRequirement) {
+      newReqList->addChild(req, Dem);
+      continue;
+    }
+
+    auto lhs = _replaceGeneralizationArg(req->getChild(0), substitutions, Dem);
+    auto rhs = _replaceGeneralizationArg(req->getChild(1), substitutions, Dem);
+
+    auto newReq = Dem.createNode(Node::Kind::DependentGenericSameTypeRequirement);
+    newReq->addChild(lhs, Dem);
+    newReq->addChild(rhs, Dem);
+
+    newReqList->addChild(newReq, Dem);
+  }
+
+  constrainedExistential->replaceChild(1, newReqList);
+
+  return demangledExistential;
+}
+
 // Build a demangled type tree for a type.
 //
 // FIXME: This should use MetadataReader.h.
@@ -596,13 +659,7 @@ swift::_swift_buildDemanglingForMetadata(const Metadata *type,
     return proto_list;
   }
   case MetadataKind::ExtendedExistential: {
-    // FIXME: Implement this by demangling the extended existential and
-    // substituting the generalization arguments into the demangle tree.
-    // For now, unconditional casts will report '<<< invalid type >>>' when
-    // they fail.
-    // TODO: for clients that need to guarantee round-tripping, demangle
-    // to a SymbolicExtendedExistentialType.
-    return nullptr;
+    return _buildDemanglingForExtendedExistential(type, Dem);
   }
   case MetadataKind::ExistentialMetatype: {
     auto metatype = static_cast<const ExistentialMetatypeMetadata *>(type);
diff --git a/stdlib/public/runtime/DynamicCast.cpp b/stdlib/public/runtime/DynamicCast.cpp
index 6f197aaca2ceb..df73bff917fbb 100644
--- a/stdlib/public/runtime/DynamicCast.cpp
+++ b/stdlib/public/runtime/DynamicCast.cpp
@@ -206,13 +206,86 @@ struct _ObjectiveCBridgeableWitnessTable : WitnessTable {
 extern "C" const ProtocolDescriptor
 PROTOCOL_DESCR_SYM(s21_ObjectiveCBridgeable);
 
+#if SWIFT_OBJC_INTEROP
+#define BRIDGING_CONFORMANCE_SYM \
+  MANGLE_SYM(s19_BridgeableMetatypeVs21_ObjectiveCBridgeablesWP)
+
+extern "C" const _ObjectiveCBridgeableWitnessTable BRIDGING_CONFORMANCE_SYM;
+#endif
+
+/// Nominal type descriptor for Swift.String.
+extern "C" const StructDescriptor NOMINAL_TYPE_DESCR_SYM(SS);
+
+struct ObjCBridgeWitnessCacheEntry {
+  const Metadata *metadata;
+  const _ObjectiveCBridgeableWitnessTable *witness;
+};
+
 static const _ObjectiveCBridgeableWitnessTable *
-findBridgeWitness(const Metadata *T) {
+swift_conformsToObjectiveCBridgeableNoCache(const Metadata *T) {
   auto w = swift_conformsToProtocolCommon(
-      T, &PROTOCOL_DESCR_SYM(s21_ObjectiveCBridgeable));
+         T, &PROTOCOL_DESCR_SYM(s21_ObjectiveCBridgeable));
   return reinterpret_cast<const _ObjectiveCBridgeableWitnessTable *>(w);
 }
 
+static const _ObjectiveCBridgeableWitnessTable *
+swift_conformsToObjectiveCBridgeable(const Metadata *T) {
+  static std::atomic<ObjCBridgeWitnessCacheEntry> _objcBridgeWitnessCache = {};
+  auto cached = _objcBridgeWitnessCache.load(SWIFT_MEMORY_ORDER_CONSUME);
+  if (cached.metadata == T) {
+    return cached.witness;
+  }
+  cached.witness = swift_conformsToObjectiveCBridgeableNoCache(T);
+  cached.metadata = T;
+  _objcBridgeWitnessCache.store(cached, std::memory_order_release);
+  return cached.witness;
+}
+
+static const _ObjectiveCBridgeableWitnessTable *
+findBridgeWitness(const Metadata *T) {
+  // Special case: Memoize the bridge witness for Swift.String.
+  // Swift.String is the most heavily used bridge because of the prevalence of
+  // string-keyed dictionaries in Obj-C.  It's worth burning a few words of static
+  // storage to avoid repeatedly looking up this conformance.
+  if (T->getKind() == MetadataKind::Struct) {
+    auto structDescription = cast<StructMetadata>(T)->Description;
+    if (structDescription == &NOMINAL_TYPE_DESCR_SYM(SS)) {
+      static auto *Swift_String_ObjectiveCBridgeable = swift_conformsToObjectiveCBridgeableNoCache(T);
+      return Swift_String_ObjectiveCBridgeable;
+    }
+  }
+
+  auto w = swift_conformsToObjectiveCBridgeable(T);
+  if (SWIFT_LIKELY(w))
+    return reinterpret_cast<const _ObjectiveCBridgeableWitnessTable *>(w);
+  // Class and ObjC existential metatypes can be bridged, but metatypes can't
+  // directly conform to protocols yet. Use a stand-in conformance for a type
+  // that looks like a metatype value if the metatype can be bridged.
+  switch (T->getKind()) {
+  case MetadataKind::Metatype: {
+#if SWIFT_OBJC_INTEROP
+    auto metaTy = static_cast<const MetatypeMetadata *>(T);
+    if (metaTy->InstanceType->isAnyClass())
+      return &BRIDGING_CONFORMANCE_SYM;
+#endif
+    break;
+  }
+  case MetadataKind::ExistentialMetatype: {
+#if SWIFT_OBJC_INTEROP
+    auto existentialMetaTy =
+      static_cast<const ExistentialMetatypeMetadata *>(T);
+    if (existentialMetaTy->isObjC())
+      return &BRIDGING_CONFORMANCE_SYM;
+#endif
+    break;
+  }
+
+  default:
+    break;
+  }
+  return nullptr;
+}
+
 /// Retrieve the bridged Objective-C type for the given type that
 /// conforms to \c _ObjectiveCBridgeable.
 MetadataResponse
@@ -734,7 +807,7 @@ struct ObjCBridgeMemo {
 #if !NDEBUG
                    memo->destType = setupData->destType;
 #endif
-                   memo->destBridgeWitness = findBridgeWitness(setupData->destType);
+                   memo->destBridgeWitness = swift_conformsToObjectiveCBridgeableNoCache(setupData->destType);
                    if (memo->destBridgeWitness == nullptr) {
                      memo->targetBridgedType = nullptr;
                      memo->targetBridgedObjCClass = nullptr;
@@ -777,6 +850,17 @@ struct ObjCBridgeMemo {
         destBridgeWitness, targetBridgedType);
     }
 };
+
+static const HashableWitnessTable* tryMemoizeNSStringHashableConformance(const Metadata *cls) {
+  auto nsString = getNSStringMetadata();
+  do {
+    if (cls == nsString) {
+      return getNSStringHashableConformance();
+    }
+    cls = _swift_class_getSuperclass(cls);
+  } while (cls != nullptr);
+  return nullptr;
+}
 #endif
 
 static DynamicCastResult
@@ -794,23 +878,16 @@ tryCastToAnyHashable(
   const HashableWitnessTable *hashableConformance = nullptr;
   
   switch (srcType->getKind()) {
+  case MetadataKind::Existential: {
+    return DynamicCastResult::Failure;
+  }
   case MetadataKind::ForeignClass: // CF -> String
   case MetadataKind::ObjCClassWrapper: { // Obj-C -> String
 #if SWIFT_OBJC_INTEROP
-    auto cls = srcType;
-    auto nsString = getNSStringMetadata();
-    do {
-      if (cls == nsString) {
-        hashableConformance = getNSStringHashableConformance();
-        break;
-      }
-      cls = _swift_class_getSuperclass(cls);
-    } while (cls != nullptr);
-    break;
-#else
+    hashableConformance = tryMemoizeNSStringHashableConformance(srcType);
+#endif
     // If no Obj-C interop, just fall through to the general case.
     break;
-#endif
   }
   case MetadataKind::Optional: {
     // FIXME: https://github.com/apple/swift/issues/51550
diff --git a/stdlib/public/runtime/EnvironmentVariables.def b/stdlib/public/runtime/EnvironmentVariables.def
index 310f7d91c6e9d..8bdd82cfe07bf 100644
--- a/stdlib/public/runtime/EnvironmentVariables.def
+++ b/stdlib/public/runtime/EnvironmentVariables.def
@@ -62,6 +62,11 @@ VARIABLE(SWIFT_DEBUG_ENABLE_SHARED_CACHE_PROTOCOL_CONFORMANCES, bool, true,
 
 #endif
 
+VARIABLE(SWIFT_DEBUG_ENABLE_CACHE_PROTOCOL_CONFORMANCES_BY_TYPE_DESCRIPTOR,
+         bool, true,
+         "Enable caching protocol conformances by type descriptor in addition "
+         "to the cache by metadata.")
+
 VARIABLE(SWIFT_DEBUG_CONCURRENCY_ENABLE_COOPERATIVE_QUEUES, bool, true,
          "Enable dispatch cooperative queues in the global executor.")
 
@@ -70,6 +75,10 @@ VARIABLE(SWIFT_DEBUG_CONCURRENCY_ENABLE_COOPERATIVE_QUEUES, bool, true,
 VARIABLE(SWIFT_DEBUG_RUNTIME_EXCLUSIVITY_LOGGING, bool, false,
          "Enable the an asserts runtime to emit logging as it works.")
 
+VARIABLE(SWIFT_DEBUG_ENABLE_PROTOCOL_CONFORMANCES_LOOKUP_LOG,
+         bool, false,
+         "Enable logs for the conformance lookup routine.")
+
 #endif
 
 VARIABLE(SWIFT_BINARY_COMPATIBILITY_VERSION, uint32_t, 0,
diff --git a/stdlib/public/runtime/Errors.cpp b/stdlib/public/runtime/Errors.cpp
index f3a2a8518a6a5..b7eeb526dc114 100644
--- a/stdlib/public/runtime/Errors.cpp
+++ b/stdlib/public/runtime/Errors.cpp
@@ -37,6 +37,9 @@
 #include "ImageInspection.h"
 #include "swift/Demangling/Demangle.h"
 #include "swift/Runtime/Atomic.h"
+#if defined(_WIN32)
+#include "swift/Runtime/Config.h"
+#endif
 #include "swift/Runtime/Debug.h"
 #include "swift/Runtime/Portability.h"
 #include "swift/Runtime/Win32.h"
@@ -506,11 +509,11 @@ void swift::swift_abortRetainUnowned(const void *object) {
   if (object) {
     swift::fatalError(FatalErrorFlags::ReportBacktrace,
                       "Fatal error: Attempted to read an unowned reference but "
-                      "object %p was already deallocated\n", object);
+                      "object %p was already destroyed\n", object);
   } else {
     swift::fatalError(FatalErrorFlags::ReportBacktrace,
                       "Fatal error: Attempted to read an unowned reference but "
-                      "the object was already deallocated\n");
+                      "the object was already destroyed\n");
   }
 }
 
@@ -544,6 +547,7 @@ void swift::swift_abortDisabledUnicodeSupport() {
 }
 
 #if defined(_WIN32)
+SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_BEGIN
 // On Windows, exceptions may be swallowed in some cases and the
 // process may not terminate as expected on crashes. For example,
 // illegal instructions used by llvm.trap. Disable the exception
@@ -555,5 +559,5 @@ static void ConfigureExceptionPolicy() {
                             UOI_TIMERPROC_EXCEPTION_SUPPRESSION,
                             &Suppress, sizeof(Suppress));
 }
-
+SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_END
 #endif
diff --git a/stdlib/public/runtime/Float16Support.cpp b/stdlib/public/runtime/Float16Support.cpp
index fa259559e4596..5f1125edf3c2a 100644
--- a/stdlib/public/runtime/Float16Support.cpp
+++ b/stdlib/public/runtime/Float16Support.cpp
@@ -31,7 +31,7 @@
 // Android NDK <r21 do not provide `__aeabi_d2h` in the compiler runtime,
 // provide shims in that case.
 #if (defined(__ANDROID__) && defined(__ARM_ARCH_7A__) && defined(__ARM_EABI__)) || \
-  ((defined(__i386__) || defined(__i686__) || defined(__x86_64__)) && !defined(__APPLE__))
+  ((defined(__i386__) || defined(__i686__) || defined(__arm__) || defined(__x86_64__)) && !defined(__APPLE__))
 
 #include "swift/shims/Visibility.h"
 
@@ -71,11 +71,11 @@ static _Float16 fromEncoding(unsigned short s) {
 // but who knows what could go wrong, and they're tiny functions.
 # include <immintrin.h>
 
-SWIFT_RUNTIME_EXPORT float __gnu_h2f_ieee(short h) {
+SWIFT_RUNTIME_EXPORT float __gnu_h2f_ieee(unsigned short h) {
   return _mm_cvtss_f32(_mm_cvtph_ps(_mm_set_epi64x(0,h)));
 }
 
-SWIFT_RUNTIME_EXPORT short __gnu_f2h_ieee(float f) {
+SWIFT_RUNTIME_EXPORT unsigned short __gnu_f2h_ieee(float f) {
   return (unsigned short)_mm_cvtsi128_si32(
     _mm_cvtps_ph(_mm_set_ss(f), _MM_FROUND_CUR_DIRECTION)
   );
diff --git a/stdlib/public/runtime/HeapObject.cpp b/stdlib/public/runtime/HeapObject.cpp
index bcddd44fdf80e..38ee10a62e6f5 100644
--- a/stdlib/public/runtime/HeapObject.cpp
+++ b/stdlib/public/runtime/HeapObject.cpp
@@ -547,6 +547,16 @@ HeapObject *swift::swift_unownedRetain(HeapObject *object) {
 #endif
 }
 
+// Assert that the metadata is a class or ErrorObject, for unowned operations.
+// Other types of metadata are not supposed to be used with unowned.
+static void checkMetadataForUnownedRR(HeapObject *object) {
+  assert(object->metadata->isClassObject() ||
+         object->metadata->getKind() == MetadataKind::ErrorObject);
+  if (object->metadata->isClassObject())
+    assert(
+        static_cast<const ClassMetadata *>(object->metadata)->isTypeMetadata());
+}
+
 void swift::swift_unownedRelease(HeapObject *object) {
 #ifdef SWIFT_THREADING_NONE
   swift_nonatomic_unownedRelease(object);
@@ -555,9 +565,7 @@ void swift::swift_unownedRelease(HeapObject *object) {
   if (!isValidPointerForNativeRetain(object))
     return;
 
-  // Only class objects can be unowned-retained and unowned-released.
-  assert(object->metadata->isClassObject());
-  assert(static_cast<const ClassMetadata*>(object->metadata)->isTypeMetadata());
+  checkMetadataForUnownedRR(object);
 
   if (object->refCounts.decrementUnownedShouldFree(1)) {
     auto classMetadata = static_cast<const ClassMetadata*>(object->metadata);
@@ -582,9 +590,7 @@ void swift::swift_nonatomic_unownedRelease(HeapObject *object) {
   if (!isValidPointerForNativeRetain(object))
     return;
 
-  // Only class objects can be unowned-retained and unowned-released.
-  assert(object->metadata->isClassObject());
-  assert(static_cast<const ClassMetadata*>(object->metadata)->isTypeMetadata());
+  checkMetadataForUnownedRR(object);
 
   if (object->refCounts.decrementUnownedShouldFreeNonAtomic(1)) {
     auto classMetadata = static_cast<const ClassMetadata*>(object->metadata);
@@ -615,9 +621,7 @@ void swift::swift_unownedRelease_n(HeapObject *object, int n) {
   if (!isValidPointerForNativeRetain(object))
     return;
 
-  // Only class objects can be unowned-retained and unowned-released.
-  assert(object->metadata->isClassObject());
-  assert(static_cast<const ClassMetadata*>(object->metadata)->isTypeMetadata());
+  checkMetadataForUnownedRR(object);
 
   if (object->refCounts.decrementUnownedShouldFree(n)) {
     auto classMetadata = static_cast<const ClassMetadata*>(object->metadata);
@@ -641,9 +645,7 @@ void swift::swift_nonatomic_unownedRelease_n(HeapObject *object, int n) {
   if (!isValidPointerForNativeRetain(object))
     return;
 
-  // Only class objects can be unowned-retained and unowned-released.
-  assert(object->metadata->isClassObject());
-  assert(static_cast<const ClassMetadata*>(object->metadata)->isTypeMetadata());
+  checkMetadataForUnownedRR(object);
 
   if (object->refCounts.decrementUnownedShouldFreeNonAtomic(n)) {
     auto classMetadata = static_cast<const ClassMetadata*>(object->metadata);
@@ -875,7 +877,7 @@ void swift::swift_deallocPartialClassInstance(HeapObject *object,
   swift_deallocClassInstance(object, allocatedSize, allocatedAlignMask);
 }
 
-#if !defined(__APPLE__) && defined(SWIFT_RUNTIME_CLOBBER_FREED_OBJECTS)
+#if !defined(__APPLE__) && SWIFT_RUNTIME_CLOBBER_FREED_OBJECTS
 static inline void memset_pattern8(void *b, const void *pattern8, size_t len) {
   char *ptr = static_cast<char *>(b);
   while (len >= 8) {
@@ -898,9 +900,9 @@ static inline void swift_deallocObjectImpl(HeapObject *object,
   }
   assert(object->refCounts.isDeiniting());
   SWIFT_RT_TRACK_INVOCATION(object, swift_deallocObject);
-#ifdef SWIFT_RUNTIME_CLOBBER_FREED_OBJECTS
+#if SWIFT_RUNTIME_CLOBBER_FREED_OBJECTS
   memset_pattern8((uint8_t *)object + sizeof(HeapObject),
-                  "\xAB\xAD\x1D\xEA\xF4\xEE\xD0\bB9",
+                  "\xF0\xEF\xBE\xAD\xDE\xED\xFE\x0F", // 0x0ffeeddeadbeeff0
                   allocatedSize - sizeof(HeapObject));
 #endif
 
diff --git a/stdlib/public/runtime/Metadata.cpp b/stdlib/public/runtime/Metadata.cpp
index ae8859203ec5d..e7d03f66aeb74 100644
--- a/stdlib/public/runtime/Metadata.cpp
+++ b/stdlib/public/runtime/Metadata.cpp
@@ -6162,9 +6162,7 @@ static void initProtocolWitness(void **slot, void *witness,
   case ProtocolRequirementFlags::Kind::Getter:
   case ProtocolRequirementFlags::Kind::Setter:
   case ProtocolRequirementFlags::Kind::ReadCoroutine:
-  case ProtocolRequirementFlags::Kind::Read2Coroutine:
   case ProtocolRequirementFlags::Kind::ModifyCoroutine:
-  case ProtocolRequirementFlags::Kind::Modify2Coroutine:
     swift_ptrauth_init_code_or_data(slot, witness,
                                     reqt.Flags.getExtraDiscriminator(),
                                     !reqt.Flags.isData());
@@ -6205,9 +6203,7 @@ static void copyProtocolWitness(void **dest, void * const *src,
   case ProtocolRequirementFlags::Kind::Getter:
   case ProtocolRequirementFlags::Kind::Setter:
   case ProtocolRequirementFlags::Kind::ReadCoroutine:
-  case ProtocolRequirementFlags::Kind::Read2Coroutine:
   case ProtocolRequirementFlags::Kind::ModifyCoroutine:
-  case ProtocolRequirementFlags::Kind::Modify2Coroutine:
     swift_ptrauth_copy_code_or_data(
         dest, src, reqt.Flags.getExtraDiscriminator(), !reqt.Flags.isData(),
         /*allowNull*/ true); // NULL allowed for VFE (methods in the vtable
@@ -7811,44 +7807,50 @@ checkMetadataDependency(MetadataDependency dependency) {
 void swift::blockOnMetadataDependency(MetadataDependency root,
                                       MetadataDependency firstLink) {
   std::vector<MetadataDependency> links;
-  auto checkNewLink = [&](MetadataDependency newLink) {
-    links.push_back(newLink);
-    for (auto i = links.begin(), e = links.end() - 1; i != e; ++i) {
-      if (i->Value == newLink.Value) {
-        diagnoseMetadataDependencyCycle(
-          llvm::makeArrayRef(&*i, links.end() - i));
-      }
-    }
-  };
-
   links.push_back(root);
 
   // Iteratively add each link, checking for a cycle, until we reach
   // something without a known dependency.
-  checkNewLink(firstLink);
-  while (true) {
+
+  // Start out with firstLink. The initial NewState value won't be
+  // used, so just initialize it to an arbitrary value.
+  MetadataStateWithDependency currentCheckResult{
+      PrivateMetadataState::Allocating, firstLink};
+
+  // If there isn't a known dependency, we can't do any more checking.
+  while (currentCheckResult.Dependency) {
+    // Add this dependency to our links.
+    links.push_back(currentCheckResult.Dependency);
+
     // Try to get a dependency for the metadata in the last link we added.
-    auto checkResult = checkMetadataDependency(links.back());
-
-    // If there isn't a known dependency, we can't do any more checking.
-    if (!checkResult.Dependency) {
-      // In the special case where it's the first link that doesn't have
-      // a known dependency and its current metadata state now satisfies
-      // the dependency leading to it, we can skip waiting.
-      if (links.size() == 2 && 
-          satisfies(checkResult.NewState, links.back().Requirement))
-        return;
-
-      // Otherwise, just make a blocking request for the first link in
-      // the chain.
-      auto request = MetadataRequest(firstLink.Requirement);
-      swift_checkMetadataState(request, firstLink.Value);
-      return;
-    }
+    currentCheckResult = checkMetadataDependency(links.back());
 
-    // Check the new link.
-    checkNewLink(checkResult.Dependency);
+    // Check the last link against the rest of the list.
+    for (auto i = links.begin(), e = links.end() - 1; i != e; ++i) {
+      if (i->Value == links.back().Value) {
+        // If there's a cycle but the new link's current state is now satisfied,
+        // then this is a stale dependency, not a cycle. This can happen when
+        // threads race to build a type in a fulfillable cycle.
+        if (!satisfies(currentCheckResult.NewState, links.back().Requirement))
+          diagnoseMetadataDependencyCycle(
+              llvm::makeArrayRef(&*i, links.end() - i));
+      }
+    }
   }
+
+  // We didn't find any cycles. Make a blocking request if appropriate.
+
+  // In the special case where it's the first link that doesn't have
+  // a known dependency and its current metadata state now satisfies
+  // the dependency leading to it, we can skip waiting.
+  if (links.size() == 2 &&
+      satisfies(currentCheckResult.NewState, links.back().Requirement))
+    return;
+
+  // Otherwise, just make a blocking request for the first link in
+  // the chain.
+  auto request = MetadataRequest(firstLink.Requirement);
+  swift_checkMetadataState(request, firstLink.Value);
 }
 
 /***************************************************************************/
@@ -7901,6 +7903,8 @@ std::tuple<const void *, size_t> MetadataAllocator::InitialPoolLocation() {
 
 bool swift::_swift_debug_metadataAllocationIterationEnabled = false;
 const void * const swift::_swift_debug_allocationPoolPointer = &AllocationPool;
+const size_t swift::_swift_debug_allocationPoolSize = InitialPoolSize;
+const size_t swift::_swift_debug_metadataAllocatorPageSize = PoolRange::PageSize;
 std::atomic<const void *> swift::_swift_debug_metadataAllocationBacktraceList;
 
 static void recordBacktrace(void *allocation) {
diff --git a/stdlib/public/runtime/MetadataLookup.cpp b/stdlib/public/runtime/MetadataLookup.cpp
index 4ef1254087d78..04d2edb545925 100644
--- a/stdlib/public/runtime/MetadataLookup.cpp
+++ b/stdlib/public/runtime/MetadataLookup.cpp
@@ -2907,25 +2907,6 @@ static NodePointer getParameterList(NodePointer funcType) {
   return parameterContainer;
 }
 
-static const Metadata *decodeType(TypeDecoder<DecodedMetadataBuilder> &decoder,
-                                  NodePointer type) {
-  assert(type->getKind() == Node::Kind::Type);
-
-  auto builtTypeOrError = decoder.decodeMangledType(type);
-
-  if (builtTypeOrError.isError()) {
-    auto err = builtTypeOrError.getError();
-    char *errStr = err->copyErrorString();
-    err->freeErrorString(errStr);
-    return nullptr;
-  }
-
-  if (!builtTypeOrError.getType().isMetadata())
-    return nullptr;
-
-  return builtTypeOrError.getType().getMetadata();
-}
-
 SWIFT_CC(swift)
 SWIFT_RUNTIME_STDLIB_SPI
 unsigned swift_func_getParameterCount(const char *typeNameStart,
@@ -3009,8 +2990,21 @@ swift_func_getParameterTypeInfo(
 
   SubstGenericParametersFromMetadata substFn(genericEnv, genericArguments);
 
-  DecodedMetadataBuilder builder(
-      demangler,
+  // for each parameter (TupleElement), store it into the provided buffer
+  for (unsigned index = 0; index != typesLength; ++index) {
+    auto nodePointer = parameterList->getChild(index);
+
+    if (nodePointer->getKind() == Node::Kind::TupleElement) {
+      assert(nodePointer->getNumChildren() == 1);
+      nodePointer = nodePointer->getFirstChild();
+    }
+    assert(nodePointer->getKind() == Node::Kind::Type);
+
+    auto request = MetadataRequest(MetadataState::Complete);
+
+    auto typeInfoOrErr = swift_getTypeByMangledNode(
+      request, demangler, nodePointer,
+      /*arguments=*/genericArguments,
       /*substGenericParam=*/
       [&substFn](unsigned depth, unsigned index) {
         return substFn.getMetadata(depth, index).Ptr;
@@ -3019,24 +3013,13 @@ swift_func_getParameterTypeInfo(
       [&substFn](const Metadata *type, unsigned index) {
         return substFn.getWitnessTable(type, index);
       });
-  TypeDecoder<DecodedMetadataBuilder> decoder(builder);
-
-  // for each parameter (TupleElement), store it into the provided buffer
-  for (unsigned index = 0; index != typesLength; ++index) {
-    auto *parameter = parameterList->getChild(index);
-
-    if (parameter->getKind() == Node::Kind::TupleElement) {
-      assert(parameter->getNumChildren() == 1);
-      parameter = parameter->getFirstChild();
-    }
-
-    assert(parameter->getKind() == Node::Kind::Type);
 
-    auto type = decodeType(decoder, parameter);
-    if (!type)
+    if (typeInfoOrErr.isError()) {
       return -3; // Failed to decode a type.
+    }
 
-    types[index] = type;
+    auto typeInfo = typeInfoOrErr.getType();
+    types[index] = typeInfo.getMetadata();
   } // end foreach parameter
 
   return typesLength;
diff --git a/stdlib/public/runtime/ProtocolConformance.cpp b/stdlib/public/runtime/ProtocolConformance.cpp
index ea1ca57c96d65..6163a68003bff 100644
--- a/stdlib/public/runtime/ProtocolConformance.cpp
+++ b/stdlib/public/runtime/ProtocolConformance.cpp
@@ -117,6 +117,15 @@ void ProtocolDescriptorFlags::dump() const {
 
 #endif
 
+static bool IsDebugLog() {
+#ifndef NDEBUG
+  return runtime::environment::
+      SWIFT_DEBUG_ENABLE_PROTOCOL_CONFORMANCES_LOOKUP_LOG();
+#else
+  return false;
+#endif
+}
+
 #if !defined(NDEBUG) && SWIFT_OBJC_INTEROP
 #include <objc/runtime.h>
 
@@ -444,8 +453,15 @@ static bool _checkWitnessTableIsolation(
   llvm::ArrayRef<const void *> conditionalArgs,
   ConformanceExecutionContext &context
 ) {
-  // If there's no protocol conformance descriptor, do nothing.
+#if SWIFT_STDLIB_USE_RELATIVE_PROTOCOL_WITNESS_TABLES
+  auto description = lookThroughOptionalConditionalWitnessTable(
+                         reinterpret_cast<const RelativeWitnessTable *>(wtable))
+                         ->getDescription();
+#else
   auto description = wtable->getDescription();
+#endif
+
+  // If there's no protocol conformance descriptor, do nothing.
   if (!description)
     return false;
 
@@ -515,73 +531,164 @@ namespace {
   };
 
   struct ConformanceCacheKey {
-    const Metadata *Type;
+    llvm::PointerUnion<const Metadata *, const TypeContextDescriptor *>
+        TypeOrDescriptor;
     const ProtocolDescriptor *Proto;
 
     ConformanceCacheKey(const Metadata *type, const ProtocolDescriptor *proto)
-        : Type(type), Proto(proto) {
+        : TypeOrDescriptor(type), Proto(proto) {
       assert(type);
     }
 
+    ConformanceCacheKey(llvm::PointerUnion<const Metadata *, const TypeContextDescriptor *> typeOrDescriptor, const ProtocolDescriptor *proto)
+        : Proto(proto) {
+      TypeOrDescriptor = typeOrDescriptor;
+      assert(typeOrDescriptor);
+    }
+
+    ConformanceCacheKey(const TypeContextDescriptor *typeDescriptor, const ProtocolDescriptor *proto)
+    : TypeOrDescriptor(typeDescriptor), Proto(proto) {
+      assert(typeDescriptor);
+    }
+
     friend llvm::hash_code hash_value(const ConformanceCacheKey &key) {
-      return llvm::hash_combine(key.Type, key.Proto);
+      return llvm::hash_combine(key.TypeOrDescriptor.getOpaqueValue(),
+                                key.Proto);
     }
   };
 
   struct ConformanceCacheEntry {
-  private:
-    ConformanceCacheKey Key;
+  public:
+    /// Storage used when we have global actor isolation on the conformance.
+    struct ExtendedStorage {
+      /// The protocol to which the type conforms.
+      const ProtocolDescriptor *Proto;
+
+      /// The global actor to which this conformance is isolated, or NULL for
+      /// a nonisolated conformances.
+      const Metadata *globalActorIsolationType = nullptr;
+
+      /// When the conformance is global-actor-isolated, this is the conformance
+      /// of globalActorIsolationType to GlobalActor.
+      const WitnessTable *globalActorIsolationWitnessTable = nullptr;
 
-    /// The witness table or along with a bit that indicates whether the
-    /// conformance is isolated to a global actor.
-    llvm::PointerUnion<const WitnessTable *, const ConformanceLookupResult *>
-        WitnessTableOrLookupResult;
+      /// The next pointer in the list of extended storage allocations.
+      ExtendedStorage *next = nullptr;
+    };
+
+    llvm::PointerUnion<const Metadata *, const TypeContextDescriptor *>
+        TypeOrDescriptor;
+    llvm::PointerUnion<const ProtocolDescriptor *, ExtendedStorage *>
+        ProtoOrStorage;
+
+    union {
+      /// The witness table. Used for type cache records.
+      const WitnessTable *Witness;
+
+      /// The conformance. Used for type descriptor cache records.
+      const ProtocolConformanceDescriptor *Conformance;
+    };
 
   public:
-    ConformanceCacheEntry(ConformanceCacheKey key,
-                          ConformanceLookupResult result)
-        : Key(key) {
-      if (result.globalActorIsolationType) {
-        WitnessTableOrLookupResult = new ConformanceLookupResult(result);
-      } else {
-        WitnessTableOrLookupResult = result.witnessTable;
+    ConformanceCacheEntry(const Metadata *type, const ProtocolDescriptor *proto,
+                          ConformanceLookupResult result,
+                          std::atomic<ExtendedStorage *> &storageHead)
+        : TypeOrDescriptor(type), Witness(result.witnessTable) {
+      if (!result.globalActorIsolationType) {
+        ProtoOrStorage = proto;
+        return;
       }
+
+      // Allocate extended storage.
+      void *memory = malloc(sizeof(ExtendedStorage));
+      auto storage = new (memory) ExtendedStorage{
+        proto, result.globalActorIsolationType,
+        result.globalActorIsolationWitnessTable
+      };
+
+      ProtoOrStorage = storage;
+
+      // Add the storage pointer to the list of extended storage allocations
+      // so that we can free them later.
+      auto head = storageHead.load(std::memory_order_relaxed);
+      while (true) {
+        storage->next = head;
+        if (storageHead.compare_exchange_weak(
+                head, storage, std::memory_order_release,
+                std::memory_order_relaxed))
+          break;
+      };
+    }
+
+    ConformanceCacheEntry(const TypeContextDescriptor *typeDescriptor,
+                          const ProtocolDescriptor *proto,
+                          const ProtocolConformanceDescriptor *conformance)
+        : TypeOrDescriptor(typeDescriptor), ProtoOrStorage(proto),
+          Conformance(conformance) {
+      assert(TypeOrDescriptor);
+      assert(ProtoOrStorage);
     }
 
     bool matchesKey(const ConformanceCacheKey &key) const {
-      return Key.Type == key.Type && Key.Proto == key.Proto;
+      return TypeOrDescriptor == key.TypeOrDescriptor && getProtocol() == key.Proto;
     }
 
     friend llvm::hash_code hash_value(const ConformanceCacheEntry &entry) {
-      return hash_value(entry.Key);
+      return hash_value(entry.getKey());
+    }
+
+    /// Get the protocol.
+    const ProtocolDescriptor *getProtocol() const {
+      if (auto proto = ProtoOrStorage.dyn_cast<const ProtocolDescriptor *>())
+        return proto;
+
+      if (auto storage = ProtoOrStorage.dyn_cast<ExtendedStorage *>())
+        return storage->Proto;
+
+      return nullptr;
+    }
+
+    /// Get the conformance cache key.
+    ConformanceCacheKey getKey() const {
+      return ConformanceCacheKey(TypeOrDescriptor, getProtocol());
     }
 
     /// Get the cached witness table, or null if we cached failure.
     const WitnessTable *getWitnessTable() const {
-      if (auto witnessTable = WitnessTableOrLookupResult.dyn_cast<const WitnessTable *>())
-        return witnessTable;
-
-      return WitnessTableOrLookupResult.get<const ConformanceLookupResult *>()
-          ->witnessTable;
+      return Witness;
     }
 
     ConformanceLookupResult getResult() const {
-      if (auto witnessTable = WitnessTableOrLookupResult.dyn_cast<const WitnessTable *>())
-        return ConformanceLookupResult { witnessTable, nullptr, nullptr };
+      if (ProtoOrStorage.is<const ProtocolDescriptor *>())
+        return ConformanceLookupResult { Witness, nullptr, nullptr };
 
-      if (auto lookupResult = WitnessTableOrLookupResult.dyn_cast<const ConformanceLookupResult *>())
-        return *lookupResult;
+      if (auto storage = ProtoOrStorage.dyn_cast<ExtendedStorage *>()) {
+        return ConformanceLookupResult(
+            Witness, storage->globalActorIsolationType,
+            storage->globalActorIsolationWitnessTable);
+      }
 
       return nullptr;
     }
   };
 } // end anonymous namespace
 
+static bool CanCacheTypeByDescriptor(const TypeContextDescriptor &descriptor) {
+  return descriptor.isGeneric();
+}
+
 // Conformance Cache.
 struct ConformanceState {
-  ConcurrentReadableHashMap<ConformanceCacheEntry> Cache;
+  using CacheType = ConcurrentReadableHashMap<ConformanceCacheEntry>;
+  CacheType Cache;
   ConcurrentReadableArray<ConformanceSection> SectionsToScan;
+
+  /// The head of an intrusive linked list that keeps track of all of the
+  /// conformance cache entries that require extended storage.
+  std::atomic<ConformanceCacheEntry::ExtendedStorage *> ExtendedStorageHead{nullptr};
+
   bool scanSectionsBackwards;
+  bool envAllowCacheByDescriptors;
 
 #if USE_DYLD_SHARED_CACHE_CONFORMANCE_TABLES
   uintptr_t dyldSharedCacheStart;
@@ -606,6 +713,8 @@ struct ConformanceState {
   ConformanceState() {
     scanSectionsBackwards =
         runtime::bincompat::useLegacyProtocolConformanceReverseIteration();
+    envAllowCacheByDescriptors = runtime::environment::
+        SWIFT_DEBUG_ENABLE_CACHE_PROTOCOL_CONFORMANCES_BY_TYPE_DESCRIPTOR();
 
 #if USE_DYLD_SHARED_CACHE_CONFORMANCE_TABLES
     if (__builtin_available(macOS 12.0, iOS 15.0, tvOS 15.0, watchOS 8.0, *)) {
@@ -641,37 +750,62 @@ struct ConformanceState {
   }
 
   void cacheResult(const Metadata *type, const ProtocolDescriptor *proto,
-                   ConformanceLookupResult result, size_t sectionsCount) {
-    Cache.getOrInsert(ConformanceCacheKey(type, proto),
-                      [&](ConformanceCacheEntry *entry, bool created) {
-                        // Create the entry if needed. If it already exists,
-                        // we're done.
-                        if (!created)
-                          return false;
-
-                        // Check the current sections count against what was
-                        // passed in. If a section count was passed in and they
-                        // don't match, then this is not an authoritative entry
-                        // and it may have been obsoleted, because the new
-                        // sections could contain a conformance in a more
-                        // specific type.
-                        //
-                        // If they DO match, then we can safely add. Another
-                        // thread might be adding new sections at this point,
-                        // but we will not race with them. That other thread
-                        // will add the new sections, then clear the cache. When
-                        // it clears the cache, it will block waiting for this
-                        // code to complete and relinquish Cache's writer lock.
-                        // If we cache a stale entry, it will be immediately
-                        // cleared.
-                        if (sectionsCount > 0 &&
-                            SectionsToScan.snapshot().count() != sectionsCount)
-                          return false; // abandon the new entry
-
-                        ::new (entry) ConformanceCacheEntry(
-                            ConformanceCacheKey(type, proto), result);
-                        return true; // keep the new entry
-                      });
+                   ConformanceLookupResult result, size_t sectionsCount,
+                   bool allowSaveDescriptor) {
+    CacheType::GetOrInsertManyScope lockedCache(Cache);
+    
+    // Check the current sections count against what was
+    // passed in. If a section count was passed in and they
+    // don't match, then this is not an authoritative entry
+    // and it may have been obsoleted, because the new
+    // sections could contain a conformance in a more
+    // specific type.
+    //
+    // If they DO match, then we can safely add. Another
+    // thread might be adding new sections at this point,
+    // but we will not race with them. That other thread
+    // will add the new sections, then clear the cache.
+    // When it clears the cache, it will block waiting for
+    // this code to complete and relinquish Cache's writer
+    // lock. If we cache a stale entry, it will be
+    // immediately cleared.
+    if (sectionsCount > 0 &&
+      SectionsToScan.snapshot().count() != sectionsCount)
+    return; // abandon the new entry
+
+    lockedCache.getOrInsert(ConformanceCacheKey(type, proto),
+                            [&](ConformanceCacheEntry *entry, bool created) {
+                              // Create the entry if needed. If it already
+                              // exists, we're done.
+                              if (!created)
+                                return false;
+
+                              ::new (entry) ConformanceCacheEntry(
+                                  type, proto, result, ExtendedStorageHead);
+                              return true; // keep the new entry
+                            });
+
+    if (auto typeDescriptor = type->getTypeContextDescriptor();
+        envAllowCacheByDescriptors && allowSaveDescriptor &&
+        typeDescriptor && result.witnessTable &&
+        CanCacheTypeByDescriptor(*typeDescriptor)) {
+#if SWIFT_STDLIB_USE_RELATIVE_PROTOCOL_WITNESS_TABLES
+      auto conformance = lookThroughOptionalConditionalWitnessTable(
+                         reinterpret_cast<const RelativeWitnessTable *>(result.witnessTable))
+                         ->getDescription();
+#else
+      auto conformance = result.witnessTable->getDescription();
+#endif
+      lockedCache.getOrInsert(ConformanceCacheKey(typeDescriptor, proto),
+                              [&](ConformanceCacheEntry *entry, bool created) {
+                                if (!created)
+                                  return false;
+
+                                ::new (entry) ConformanceCacheEntry(
+                                    typeDescriptor, proto, conformance);
+                                return true;
+                              });
+    }
   }
 
 #ifndef NDEBUG
@@ -703,7 +837,20 @@ static void _registerProtocolConformances(ConformanceState &C,
 
   // Blow away the conformances cache to get rid of any negative entries that
   // may now be obsolete.
-  C.Cache.clear();
+  C.Cache.clear([&](ConcurrentFreeListNode *&freeListHead) {
+    // The extended storage for conformance entries will need to be freed
+    // eventually. Put it on the concurrent free list so the cache will do so.
+    auto storageHead = C.ExtendedStorageHead.load(std::memory_order_relaxed);
+    while (storageHead) {
+      auto current = storageHead;
+      auto newHead = current->next;
+      if (C.ExtendedStorageHead.compare_exchange_weak(
+              storageHead, newHead, std::memory_order_release,
+              std::memory_order_relaxed)) {
+        ConcurrentFreeListNode::add(&freeListHead, current);
+      }
+    }
+  });
 }
 
 void swift::addImageProtocolConformanceBlockCallbackUnsafe(
@@ -779,12 +926,40 @@ swift::swift_registerProtocolConformances(const ProtocolConformanceRecord *begin
   _registerProtocolConformances(C, ConformanceSection{begin, end});
 }
 
+// Result of `searchInConformanceCache`
+struct SearchInConformanceCacheResult {
+  enum class Source {
+    None,
+    TypeMetadata,
+    TypeDescriptor,
+  };
+
+  /// `IsAuthoritative` is `true` if the result is for the type itself and not a
+  /// superclass. If `false` then we cached a conformance on a superclass, but
+  /// that may be overridden.
+  bool IsAuthoritative;
+  ConformanceLookupResult Result;
+#ifndef NDEBUG
+  Source Source; // For logging purpose
+#endif
+
+  SearchInConformanceCacheResult(bool isAuthoritative,
+                                 ConformanceLookupResult result,
+                                 enum Source source)
+      : IsAuthoritative(isAuthoritative), Result(result)
+#ifndef NDEBUG
+        , Source(source)
+#endif
+  {}
+
+  static SearchInConformanceCacheResult NotFound() {
+    return SearchInConformanceCacheResult(false, {},
+                                          Source::None);
+  }
+};
+
 /// Search for a conformance descriptor in the ConformanceCache.
-/// First element of the return value is `true` if the result is authoritative
-/// i.e. the result is for the type itself and not a superclass. If `false`
-/// then we cached a conformance on a superclass, but that may be overridden.
-/// A return value of `{ false, { } }` indicates nothing was cached.
-static std::pair<bool, ConformanceLookupResult>
+static SearchInConformanceCacheResult
 searchInConformanceCache(const Metadata *type,
                          const ProtocolDescriptor *protocol,
                          bool instantiateSuperclassMetadata) {
@@ -795,13 +970,47 @@ searchInConformanceCache(const Metadata *type,
   MaybeIncompleteSuperclassIterator superclassIterator{
       type, instantiateSuperclassMetadata};
   for (; auto type = superclassIterator.metadata; ++superclassIterator) {
-    if (auto *Value = snapshot.find(ConformanceCacheKey(type, protocol))) {
-      return { type == origType, Value->getResult() };
+    if (auto *cacheEntry = snapshot.find(ConformanceCacheKey(type, protocol))) {
+      return SearchInConformanceCacheResult(
+          type == origType, cacheEntry->getResult(),
+          SearchInConformanceCacheResult::Source::TypeMetadata);
+    }
+    if (auto *typeDescriptor = type->getTypeContextDescriptor();
+        typeDescriptor && CanCacheTypeByDescriptor(*typeDescriptor)) {
+      auto *cacheEntry =
+          snapshot.find(ConformanceCacheKey(typeDescriptor, protocol));
+      if (!cacheEntry)
+        continue;
+      auto conformanceDescriptor = cacheEntry->Conformance;
+      auto result =
+          ConformanceLookupResult::fromConformance(type, conformanceDescriptor);
+      // In case we couldn't get a witness table from the cached conformance
+      // for this type. While it's possible we could find another conformance
+      // that satisfies the requirements, we do NOT attempt to find it.
+      // We cache it and return the result immediatelly.
+      // This aligns with the current logic of the scanning:
+      // When we find a conformance for the given type and protocol we attempt
+      // to get the witness table and cache it and put into `foundWitnesses` no
+      // matter if the witness is nullptr. If we find another conformance in
+      // subsequent iterations we will get the witness and attempt to insert it
+      // into the cache and `foundWitnesses` as well, but both of them will NOT
+      // override the existing entry saved earlier. Later we select the first
+      // witness in `foundWitnesses` in order of hierarchy even if it's null.
+      // See the test case `(GenericSubClass<Int>() as Any as! Hello).hello()`
+      // in `test/multifile/protocol-conformance-redundant.swift` for example.
+      auto sectionsCount = C.SectionsToScan.snapshot().count();
+      bool allowSaveDescriptor = false;
+      C.cacheResult(type, protocol, result, sectionsCount,
+                    allowSaveDescriptor);
+      auto isAuthoritative = origType == type;
+      return SearchInConformanceCacheResult(
+          isAuthoritative, result,
+          SearchInConformanceCacheResult::Source::TypeDescriptor);
     }
   }
 
   // We did not find a cache entry.
-  return { false, ConformanceLookupResult{} };
+  return SearchInConformanceCacheResult::NotFound();
 }
 
 /// Get the appropriate context descriptor for a type. If the descriptor is a
@@ -1197,19 +1406,43 @@ swift_conformsToProtocolMaybeInstantiateSuperclasses(
         return {dyldCachedWitnessTable, false};
   }
 
+  auto debugLogResult = [&](bool found, const char *source) {
+    if (IsDebugLog()) {
+      auto typeName = swift_getTypeName(type, true);
+      const char *status = found ? "found" : "not found";
+      fprintf(stderr, "Check confomance %.*s to %s: %s, source: %s\n",
+             (int)typeName.length, typeName.data, protocol->Name.get(), status,
+             source);
+    }
+  };
+
   // See if we have an authoritative cached conformance. The
   // ConcurrentReadableHashMap data structure allows us to search the map
   // concurrently without locking.
-  auto found =
-      searchInConformanceCache(type, protocol, instantiateSuperclassMetadata);
-  if (found.first) {
+  if (auto cacheSearchResult = searchInConformanceCache(
+          type, protocol, instantiateSuperclassMetadata);
+      cacheSearchResult.IsAuthoritative) {
     // An authoritative negative result can be overridden by a result from dyld.
-    if (!found.second.witnessTable) {
+    if (!cacheSearchResult.Result.witnessTable) {
       if (dyldCachedWitnessTable)
         return {dyldCachedWitnessTable, false};
     }
-
-    return {found.second, false};
+#ifndef NDEBUG
+    const char *source;
+    switch (cacheSearchResult.Source) {
+    case SearchInConformanceCacheResult::Source::None:
+      source = "unknown";
+      break;
+    case SearchInConformanceCacheResult::Source::TypeMetadata:
+      source = "cache by type metadata";
+      break;
+    case SearchInConformanceCacheResult::Source::TypeDescriptor:
+      source = "cache by type descriptor";
+      break;
+    }
+    debugLogResult(cacheSearchResult.Result.witnessTable != nullptr,  source);
+#endif
+    return {cacheSearchResult.Result, false};
   }
 
   if (dyldCachedConformanceDescriptor) {
@@ -1219,7 +1452,8 @@ swift_conformsToProtocolMaybeInstantiateSuperclasses(
     assert(matchingType);
     auto witness = ConformanceLookupResult::fromConformance(
         matchingType, dyldCachedConformanceDescriptor);
-    C.cacheResult(type, protocol, witness, /*always cache*/ 0);
+    bool allowSaveDescriptor = false; // already have it in the dyld cache
+    C.cacheResult(type, protocol, witness, /*always cache*/ 0, allowSaveDescriptor);
     DYLD_CONFORMANCES_LOG("Caching generic conformance to %s found by DYLD",
                           protocol->Name.get());
     return {witness, false};
@@ -1246,7 +1480,8 @@ swift_conformsToProtocolMaybeInstantiateSuperclasses(
       if (matchingType) {
         auto witness = ConformanceLookupResult::fromConformance(
             matchingType, &descriptor);
-        C.cacheResult(matchingType, protocol, witness, /*always cache*/ 0);
+        bool allowSaveDescriptor = true;
+        C.cacheResult(matchingType, protocol, witness, /*always cache*/ 0, allowSaveDescriptor);
         foundWitnesses.insert({matchingType, witness});
       }
     };
@@ -1279,10 +1514,10 @@ swift_conformsToProtocolMaybeInstantiateSuperclasses(
   MaybeIncompleteSuperclassIterator superclassIterator{
       type, instantiateSuperclassMetadata};
   for (; auto searchType = superclassIterator.metadata; ++superclassIterator) {
-    auto witness = foundWitnesses.lookup(searchType);
-    if (witness) {
+    const auto witnessIt = foundWitnesses.find(searchType);
+    if (witnessIt != foundWitnesses.end()) {
       if (!foundType) {
-        foundWitness = witness;
+        foundWitness = witnessIt->getSecond(); // may be null
         foundType = searchType;
       } else {
         auto foundName = swift_getTypeName(foundType, true);
@@ -1307,13 +1542,16 @@ swift_conformsToProtocolMaybeInstantiateSuperclasses(
     // Do not cache negative results if there were uninstantiated superclasses
     // we didn't search. They might have a conformance that will be found later.
     if (foundWitness || !hasUninstantiatedSuperclass)
-      C.cacheResult(type, protocol, foundWitness, snapshot.count());
+      C.cacheResult(type, protocol, foundWitness, snapshot.count(), /* allowSaveDescriptor */ false);
 
   // A negative result can be overridden by a result from dyld.
   if (!foundWitness) {
-    if (dyldCachedWitnessTable)
+    if (dyldCachedWitnessTable) {
+      debugLogResult(true, "dyld cache");
       return {dyldCachedWitnessTable, false};
+    }
   }
+  debugLogResult(static_cast<bool>(foundWitness), "section scan");
   return {foundWitness, hasUninstantiatedSuperclass};
 }
 
@@ -1395,8 +1633,9 @@ static bool swift_isInConformanceExecutionContextImpl(
     return true;
 
   if (context->globalActorIsolationType) {
+    // If the hook is not installed, assume we're on the right actor.
     if (!_swift_task_isCurrentGlobalActorHook)
-      return false;
+      return true;
 
     // Check whether we are running on this global actor.
     if (!_swift_task_isCurrentGlobalActorHook(
diff --git a/stdlib/public/runtime/SwiftObject.mm b/stdlib/public/runtime/SwiftObject.mm
index 0cdeec5fbf2c0..97d28325ed162 100644
--- a/stdlib/public/runtime/SwiftObject.mm
+++ b/stdlib/public/runtime/SwiftObject.mm
@@ -438,7 +438,13 @@ - (BOOL)isEqual:(id)other {
     // Legacy behavior: Don't proxy to Swift Hashable or Equatable
     return NO; // We know the ids are different
   }
-
+  if (isObjCTaggedPointer(other)) {
+    // Swift class types cannot be tagged, and a Swift Equatable conformance
+    // cannot validly be called for an object of a different type, so this can
+    // only be incorrect if someone has an Equatable that's invalid in an
+    // extremely specific way (unsafeBitCasting `other` to an unrelated type)
+    return NO;
+  }
 
   // Get Swift type for self and other
   auto selfMetadata = _swift_getClassOfAllocated(self);
diff --git a/stdlib/public/runtime/SwiftRT-ELF-WASM.cpp b/stdlib/public/runtime/SwiftRT-ELF-WASM.cpp
index 032a97cd442e4..1bd1eed9f807f 100644
--- a/stdlib/public/runtime/SwiftRT-ELF-WASM.cpp
+++ b/stdlib/public/runtime/SwiftRT-ELF-WASM.cpp
@@ -13,6 +13,7 @@
 #include "ImageInspectionCommon.h"
 #include "swift/shims/MetadataSections.h"
 #include "swift/Runtime/Backtrace.h"
+#include "swift/Runtime/Config.h"
 
 #include <cstddef>
 #include <new>
@@ -84,6 +85,7 @@ namespace {
 static swift::MetadataSections sections{};
 }
 
+SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_BEGIN
 __attribute__((__constructor__))
 static void swift_image_constructor() {
 #define SWIFT_SECTION_RANGE(name)                                              \
@@ -119,3 +121,4 @@ static void swift_image_constructor() {
 
   swift_addNewDSOImage(&sections);
 }
+SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_END
diff --git a/stdlib/public/stubs/FoundationHelpers.mm b/stdlib/public/stubs/FoundationHelpers.mm
index ad50612519185..0443eddbfbbb4 100644
--- a/stdlib/public/stubs/FoundationHelpers.mm
+++ b/stdlib/public/stubs/FoundationHelpers.mm
@@ -106,6 +106,19 @@ typedef __swift_uint8_t (*getCStringImplPtr)(id,
 
 }
 
+SWIFT_RUNTIME_STDLIB_API
+_swift_shims_NSUInteger
+_swift_stdlib_NSStringLengthOfBytesInEncodingTrampoline(id _Nonnull obj,
+                                                        unsigned long encoding) {
+  typedef _swift_shims_NSUInteger (*getLengthImplPtr)(id,
+                                                      SEL,
+                                                      unsigned long);
+  SEL sel = @selector(lengthOfBytesUsingEncoding:);
+  getLengthImplPtr imp = (getLengthImplPtr)class_getMethodImplementation([obj superclass], sel);
+  
+  return imp(obj, sel, encoding);
+}
+
 __swift_uint8_t
 _swift_stdlib_dyld_is_objc_constant_string(const void *addr) {
   return (SWIFT_RUNTIME_WEAK_CHECK(_dyld_is_objc_constant)
diff --git a/stdlib/public/stubs/LibcShims.cpp b/stdlib/public/stubs/LibcShims.cpp
index b5e39f5d05df5..1fbfaa7229096 100644
--- a/stdlib/public/stubs/LibcShims.cpp
+++ b/stdlib/public/stubs/LibcShims.cpp
@@ -25,15 +25,20 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#if defined(_WIN32)
+#include "swift/Runtime/Config.h"
+#endif
 #include "swift/shims/LibcShims.h"
 
 #if defined(_WIN32)
+SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_BEGIN
 static void __attribute__((__constructor__))
 _swift_stdlib_configure_console_mode(void) {
   static UINT uiPrevConsoleCP = GetConsoleOutputCP();
   atexit([]() { SetConsoleOutputCP(uiPrevConsoleCP); });
   SetConsoleOutputCP(CP_UTF8);
 }
+SWIFT_ALLOWED_RUNTIME_GLOBAL_CTOR_END
 #endif
 
 SWIFT_RUNTIME_STDLIB_INTERNAL
diff --git a/stdlib/toolchain/CMakeLists.txt b/stdlib/toolchain/CMakeLists.txt
index 81afa1c74d591..0b833153bcd48 100644
--- a/stdlib/toolchain/CMakeLists.txt
+++ b/stdlib/toolchain/CMakeLists.txt
@@ -1,5 +1,13 @@
 # Toolchain-only build products
 
+# `-fsized-deallocation` would cause a build failure
+# when targeting macOS 14.0 SDK used in some configuration
+get_property(directory_compile_options
+  DIRECTORY
+  PROPERTY COMPILE_OPTIONS)
+list(FILTER directory_compile_options EXCLUDE REGEX ".*-fsized-deallocation.*")
+set_property(DIRECTORY PROPERTY COMPILE_OPTIONS ${directory_compile_options})
+
 list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/../cmake/modules)
 include(StdlibOptions)
 include(AddSwiftStdlib)
diff --git a/stdlib/toolchain/CompatibilityDynamicReplacements/DynamicReplaceable.cpp b/stdlib/toolchain/CompatibilityDynamicReplacements/DynamicReplaceable.cpp
index 63785be88af64..c39d043976bd2 100644
--- a/stdlib/toolchain/CompatibilityDynamicReplacements/DynamicReplaceable.cpp
+++ b/stdlib/toolchain/CompatibilityDynamicReplacements/DynamicReplaceable.cpp
@@ -52,7 +52,7 @@ extern "C" char *swift_getFunctionReplacement50(char **ReplFnPtr, char *CurrFn)
 
   auto origKey = compat50Key.get();
   if ((origKey & 0x1) != 0) {
-    auto mask = ((uintptr_t)-1) < 1;
+    auto mask = ((uintptr_t)-1) << 1;
     auto resetKey = origKey & mask;
     compat50Key.set(resetKey);
     return nullptr;
diff --git a/stdlib/toolchain/CompatibilitySpan/CMakeLists.txt b/stdlib/toolchain/CompatibilitySpan/CMakeLists.txt
index 6001aa6f38eef..06b90b2949b34 100644
--- a/stdlib/toolchain/CompatibilitySpan/CMakeLists.txt
+++ b/stdlib/toolchain/CompatibilitySpan/CMakeLists.txt
@@ -4,6 +4,10 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND DEFINED SWIFT_STDLIB_LIBRARY_BUILD_TY
 
   add_swift_target_library("${library_name}" ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
     FakeStdlib.swift
+    ../../public/core/Span/MutableRawSpan.swift
+    ../../public/core/Span/MutableSpan.swift
+    ../../public/core/Span/OutputRawSpan.swift
+    ../../public/core/Span/OutputSpan.swift
     ../../public/core/Span/RawSpan.swift
     ../../public/core/Span/Span.swift
 
@@ -17,12 +21,14 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND DEFINED SWIFT_STDLIB_LIBRARY_BUILD_TY
       -module-abi-name Swift
       -DSPAN_COMPATIBILITY_STUB
 
-    DEPLOYMENT_VERSION_OSX ${COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_OSX}
-    DEPLOYMENT_VERSION_IOS ${COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_IOS}
-    DEPLOYMENT_VERSION_TVOS ${COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_TVOS}
-    DEPLOYMENT_VERSION_WATCHOS ${COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_WATCHOS}
-    DEPLOYMENT_VERSION_XROS ${COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_XROS}
-    DEPLOYMENT_VERSION_MACCATALYST ${COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_MACCATALYST}
+    NO_SWIFTMODULE
+
+    DEPLOYMENT_VERSION_OSX "10.14.4"
+    DEPLOYMENT_VERSION_IOS "12.2"
+    DEPLOYMENT_VERSION_TVOS "12.2"
+    DEPLOYMENT_VERSION_WATCHOS "5.2"
+    DEPLOYMENT_VERSION_XROS "1.0"
+    DEPLOYMENT_VERSION_MACCATALYST "13.1"
 
     MACCATALYST_BUILD_FLAVOR "zippered"
 
diff --git a/stdlib/toolchain/CompatibilitySpan/FakeStdlib.swift b/stdlib/toolchain/CompatibilitySpan/FakeStdlib.swift
index f4ef65f587cde..864bb77224a65 100644
--- a/stdlib/toolchain/CompatibilitySpan/FakeStdlib.swift
+++ b/stdlib/toolchain/CompatibilitySpan/FakeStdlib.swift
@@ -59,11 +59,26 @@ internal func _overrideLifetime<
   dependent
 }
 
+@unsafe
+@_unsafeNonescapableResult
+@_alwaysEmitIntoClient
+@_transparent
+@lifetime(&source)
+internal func _overrideLifetime<
+  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
+>(
+  _ dependent: consuming T,
+  mutating source: inout U
+) -> T {
+  dependent
+}
+
 extension Range {
-    @_alwaysEmitIntoClient
-	internal init(_uncheckedBounds bounds: (lower: Bound, upper: Bound)) {
-	    self.init(uncheckedBounds: bounds)
-	}
+  @unsafe
+  @_alwaysEmitIntoClient
+  internal init(_uncheckedBounds bounds: (lower: Bound, upper: Bound)) {
+    self.init(uncheckedBounds: bounds)
+  }
 }
 
 extension Optional {
@@ -76,4 +91,4 @@ extension Optional {
       _internalInvariantFailure("_unsafelyUnwrappedUnchecked of nil optional")
     }
   }
-}
\ No newline at end of file
+}
diff --git a/stdlib/tools/swift-reflection-test/messages.h b/stdlib/tools/swift-reflection-test/messages.h
index 7e91f8e2945f8..2353b59d2f6f2 100644
--- a/stdlib/tools/swift-reflection-test/messages.h
+++ b/stdlib/tools/swift-reflection-test/messages.h
@@ -29,5 +29,6 @@ typedef enum InstanceKind {
   Closure,
   Enum,
   EnumValue,
-  AsyncTask
+  AsyncTask,
+  LogString,
 } InstanceKind;
diff --git a/stdlib/tools/swift-reflection-test/swift-reflection-test.c b/stdlib/tools/swift-reflection-test/swift-reflection-test.c
index ce749e1b83c1e..d03f1b952af0f 100644
--- a/stdlib/tools/swift-reflection-test/swift-reflection-test.c
+++ b/stdlib/tools/swift-reflection-test/swift-reflection-test.c
@@ -23,6 +23,7 @@
 #include <assert.h>
 #include <errno.h>
 #include <inttypes.h>
+#include <stdarg.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -84,6 +85,20 @@ static void errnoAndExit(const char *message) {
 #define DEBUG_LOG(fmt, ...) (void)0
 #endif
 
+#ifdef __clang__
+__attribute((__format__(__printf__, 2, 3)))
+#endif
+static void
+indented_printf(unsigned indentLevel, const char *fmt, ...) {
+  for (unsigned i = 0; i < indentLevel; i++)
+    fputs("  ", stdout);
+
+  va_list args;
+  va_start(args, fmt);
+  vprintf(fmt, args);
+  va_end(args);
+}
+
 static const size_t ReadEnd = 0;
 static const size_t WriteEnd = 1;
 
@@ -774,10 +789,40 @@ int reflectEnumValue(SwiftReflectionContextRef RC,
 
 }
 
-int reflectAsyncTask(SwiftReflectionContextRef RC,
-                     const PipeMemoryReader *Reader) {
-  uintptr_t AsyncTaskInstance = PipeMemoryReader_receiveInstanceAddress(Reader);
-  printf("Async task %#" PRIx64 "\n", (uint64_t)AsyncTaskInstance);
+static int reflectAsyncTaskInstance(SwiftReflectionContextRef RC,
+                                    uintptr_t AsyncTaskInstance,
+                                    const PipeMemoryReader *Reader,
+                                    unsigned indentLevel) {
+  indented_printf(indentLevel, "Async task %#" PRIx64 "\n",
+                  (uint64_t)AsyncTaskInstance);
+
+  swift_async_task_info_t TaskInfo =
+      swift_reflection_asyncTaskInfo(RC, AsyncTaskInstance);
+  if (TaskInfo.Error) {
+    printf("swift_reflection_asyncTaskInfo failed: %s\n", TaskInfo.Error);
+  } else {
+    indented_printf(indentLevel, "id %" PRIu64 "\n", TaskInfo.Id);
+    indented_printf(indentLevel, "enqueuePriority %u\n",
+                    TaskInfo.EnqueuePriority);
+    if (TaskInfo.ChildTaskCount > 0) {
+      indented_printf(indentLevel, "children = {\n");
+
+      // The memory for ChildTasks is only valid until the next Remote Mirror
+      // call, so we need to copy it.
+      swift_reflection_ptr_t *ChildTasks =
+          calloc(TaskInfo.ChildTaskCount, sizeof(swift_reflection_ptr_t));
+      memcpy(ChildTasks, TaskInfo.ChildTasks,
+             TaskInfo.ChildTaskCount * sizeof(swift_reflection_ptr_t));
+
+      for (unsigned i = 0; i < TaskInfo.ChildTaskCount; i++)
+        reflectAsyncTaskInstance(RC, ChildTasks[i], Reader, indentLevel + 1);
+
+      free(ChildTasks);
+      indented_printf(indentLevel, "}\n");
+    } else {
+      indented_printf(indentLevel, "children = {}\n");
+    }
+  }
 
   swift_async_task_slab_return_t SlabPtrResult =
       swift_reflection_asyncTaskSlabPointer(RC, AsyncTaskInstance);
@@ -787,33 +832,67 @@ int reflectAsyncTask(SwiftReflectionContextRef RC,
   } else {
     swift_reflection_ptr_t SlabPtr = SlabPtrResult.SlabPtr;
     while (SlabPtr) {
-      printf("  Slab pointer %#" PRIx64 "\n", (uint64_t)SlabPtr);
+      indented_printf(indentLevel, "  Slab pointer %#" PRIx64 "\n",
+                      (uint64_t)SlabPtr);
       swift_async_task_slab_allocations_return_t AllocationsResult =
           swift_reflection_asyncTaskSlabAllocations(RC, SlabPtr);
       if (AllocationsResult.Error) {
-        printf("swift_reflection_asyncTaskSlabAllocations failed: %s\n",
-               AllocationsResult.Error);
+        indented_printf(
+            indentLevel,
+            "swift_reflection_asyncTaskSlabAllocations failed: %s\n",
+            AllocationsResult.Error);
         SlabPtr = 0;
       } else {
-        printf("    Slab size %" PRIu64 "\n",
-               (uint64_t)AllocationsResult.SlabSize);
+        indented_printf(indentLevel, "    Slab size %" PRIu64 "\n",
+                        (uint64_t)AllocationsResult.SlabSize);
         for (unsigned i = 0; i < AllocationsResult.ChunkCount; i++) {
           swift_async_task_allocation_chunk_t Chunk =
               AllocationsResult.Chunks[i];
-          printf("    Chunk at %#" PRIx64 " length %u kind %u\n",
-                 (uint64_t)Chunk.Start, Chunk.Length, Chunk.Kind);
+          indented_printf(indentLevel,
+                          "    Chunk at %#" PRIx64 " length %u kind %u\n",
+                          (uint64_t)Chunk.Start, Chunk.Length, Chunk.Kind);
         }
         SlabPtr = AllocationsResult.NextSlab;
       }
     }
   }
 
-  printf("\n\n");
-  PipeMemoryReader_sendDoneMessage(Reader);
+  if (indentLevel == 0) {
+    printf("\n\n");
+  }
   fflush(stdout);
   return 1;
 }
 
+int reflectAsyncTask(SwiftReflectionContextRef RC,
+                     const PipeMemoryReader *Reader) {
+  uintptr_t AsyncTaskInstance = PipeMemoryReader_receiveInstanceAddress(Reader);
+  int result = reflectAsyncTaskInstance(RC, AsyncTaskInstance, Reader, 0);
+  PipeMemoryReader_sendDoneMessage(Reader);
+  return result;
+}
+
+int logString(SwiftReflectionContextRef RC, const PipeMemoryReader *Reader) {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wcast-qual"
+  void *Context = (void *)Reader;
+#pragma clang diagnostic pop
+
+  swift_addr_t StringPointer = PipeMemoryReader_receiveInstanceAddress(Context);
+  uint64_t StringLength =
+      PipeMemoryReader_getStringLength(Context, StringPointer);
+
+  void *FreeContext;
+  // Read length+1 bytes to get the NUL terminator too.
+  const void *String = PipeMemoryReader_readBytes(
+      Context, StringPointer, StringLength + 1, &FreeContext);
+
+  printf("%s\n", (const char *)String);
+  PipeMemoryReader_freeBytes(Context, String, FreeContext);
+
+  PipeMemoryReader_sendDoneMessage(Context);
+  return 1;
+}
 
 int doDumpHeapInstance(const char *BinaryFilename, PipeMemoryReader *Reader) {
 #if defined(_WIN32)
@@ -926,6 +1005,11 @@ int doDumpHeapInstance(const char *BinaryFilename, PipeMemoryReader *Reader) {
             return EXIT_SUCCESS;
           break;
         }
+        case LogString: {
+          if (!logString(RC, Reader))
+            return EXIT_SUCCESS;
+          break;
+        }
         case None:
           swift_reflection_destroyReflectionContext(RC);
           printf("Done.\n");
diff --git a/test/APIJSON/objc-implement.swift b/test/APIJSON/objc-implement.swift
new file mode 100644
index 0000000000000..9913c81bd696f
--- /dev/null
+++ b/test/APIJSON/objc-implement.swift
@@ -0,0 +1,67 @@
+// REQUIRES: objc_interop, OS=macosx
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/ModuleCache)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) %t/objc-implement.swift -typecheck -parse-as-library -emit-module-interface-path %t/ObjcImplement.swiftinterface -enable-library-evolution -module-name ObjcImplement -import-underlying-module -swift-version 5 -emit-api-descriptor-path %t/api.json
+// RUN: %validate-json %t/api.json | %FileCheck %s
+
+//--- objc-implement.swift
+import Foundation
+
+// API record for ObjCClass shouldn't be emitted from swift.
+@objc @implementation
+extension ObjCClass {
+  init?(char: CChar) {}
+}
+
+// API record for ObjCClass and ObjCCategory shouldn't be emitted from swift.
+@objc(ObjCCategory) @implementation
+extension ObjCClass {
+  convenience init?(int: Int32) {}
+}
+
+// This is an actual class declaration that should be included in the API
+// descriptor.
+@objc
+public class SwiftObjCClass: NSObject {}
+
+//--- ObjcImplement.h
+@interface Root
+@end
+
+@interface ObjCClass : Root
+- (instancetype) initWithChar:(char)c;
+@end
+
+@interface ObjCClass (ObjCCategory)
+- (instancetype) initWithInt:(int)i;
+@end
+
+//--- module.modulemap
+module ObjcImplement {
+  header "ObjcImplement.h"
+  export *
+}
+
+
+// CHECK-NOT: "file": "{{.*}}.h"
+
+// CHECK:      "interfaces": [
+// CHECK-NEXT:    {
+// CHECK-NEXT:      "name": "_TtC13ObjcImplement14SwiftObjCClass",
+// CHECK-NEXT:      "access": "public",
+// CHECK-NEXT:      "file": "{{.*}}/objc-implement.swift",
+// CHECK-NEXT:      "linkage": "exported",
+// CHECK-NEXT:      "super": "NSObject",
+// CHECK-NEXT:      "instanceMethods": [
+// CHECK-NEXT:        {
+// CHECK-NEXT:          "name": "init",
+// CHECK-NEXT:          "access": "public",
+// CHECK-NEXT:          "file": "{{.*}}/objc-implement.swift"
+// CHECK-NEXT:        }
+// CHECK-NEXT:      ],
+// CHECK-NEXT:      "classMethods": []
+// CHECK-NEXT:    }
+// CHECK-NEXT: ],
+// CHECK-NEXT: "categories": [],
+// CHECK-NEXT: "version": "1.0"
diff --git a/test/APINotes/Inputs/broken-modules/BrokenAPINotes.apinotes b/test/APINotes/Inputs/broken-modules/BrokenAPINotes.apinotes
index ef6e86a96e882..c8a9dd0ecd2b1 100644
--- a/test/APINotes/Inputs/broken-modules/BrokenAPINotes.apinotes
+++ b/test/APINotes/Inputs/broken-modules/BrokenAPINotes.apinotes
@@ -13,4 +13,4 @@ Functions:
   - Name: ZXSpectrumSetMisnamedRegister
     SwiftName: 'setter:ZXSpectrum.misnamedRegister(self:newValue:)'
   - Name: ZXSpectrumHelperReset
-    SwiftName: 'ZXSpectrum.Helper.reset()'
+    SwiftName: 'ZXSpectrum::Helper.reset()'
diff --git a/test/APINotes/basic.swift b/test/APINotes/basic.swift
index 61e1193b03e09..3a6310463f368 100644
--- a/test/APINotes/basic.swift
+++ b/test/APINotes/basic.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -I %S/Inputs/custom-modules -F %S/Inputs/custom-frameworks
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs/custom-modules -F %S/Inputs/custom-frameworks
 import APINotesTest
 import APINotesFrameworkTest
 
diff --git a/test/APINotes/basic_version_independent.swift b/test/APINotes/basic_version_independent.swift
new file mode 100644
index 0000000000000..7e8aa7a1d7d64
--- /dev/null
+++ b/test/APINotes/basic_version_independent.swift
@@ -0,0 +1,49 @@
+// REQUIRES: objc_interop
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/InputClangModules)
+// RUN: split-file %s %t
+
+// - Fixup the input module file map
+// RUN: sed -e "s|INPUTSDIR|%/t/InputClangModules|g" %t/map.json.template > %t/map.json.template1
+// RUN: sed -e "s|STDLIBMOD|%/stdlib_module|g" %t/map.json.template1 > %t/map.json.template2
+// RUN: sed -e "s|ONONEMOD|%/ononesupport_module|g" %t/map.json.template2 > %t/map.json.template3
+// RUN: sed -e "s|CUSTOMFRAMEWORKS|%S/Inputs/custom-frameworks|g" %t/map.json.template3 > %t/map.json.template4
+// RUN: sed -e "s|SWIFTLIBDIR|%swift-lib-dir|g" %t/map.json.template4 > %t/map.json
+
+// - Set up explicit dependencies for Client
+// RUN: %target-swift-emit-pcm -module-name SwiftShims %swift-lib-dir/swift/shims/module.modulemap -o %t/InputClangModules/SwiftShims.pcm -Xcc -fswift-version-independent-apinotes
+
+// - Build the APINotesFrameworkTest module using verison-independent APINotes
+// RUN: %target-swift-emit-pcm -module-name APINotesFrameworkTest %S/Inputs/custom-frameworks/APINotesFrameworkTest.framework/Modules/module.modulemap -o %t/InputClangModules/APINotesFrameworkTest.pcm -Xcc -I -Xcc %S/Inputs/custom-frameworks/APINotesFrameworkTest.framework/Headers -Xcc -F -Xcc %S/Inputs/custom-frameworks -Xcc -fswift-version-independent-apinotes
+
+// - Build the client
+// RUN: %target-swift-frontend -typecheck -verify %t/client.swift -explicit-swift-module-map-file %t/map.json -disable-implicit-swift-modules -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -version-independent-apinotes
+
+//--- map.json.template
+[
+  {
+      "moduleName": "Swift",
+      "modulePath": "STDLIBMOD",
+      "isFramework": false
+  },
+  {
+      "moduleName": "SwiftOnoneSupport",
+      "modulePath": "ONONEMOD",
+      "isFramework": false
+  },
+  {
+      "moduleName": "SwiftShims",
+      "isFramework": false,
+      "clangModuleMapPath": "SWIFTLIBDIR/swift/shims/module.modulemap",
+      "clangModulePath": "INPUTSDIR/SwiftShims.pcm"
+  },
+  {
+      "moduleName": "APINotesFrameworkTest",
+      "isFramework": true,
+      "clangModuleMapPath": "CUSTOMFRAMEWORKS/APINotesFrameworkTest.framework/Modules/module.modulemap",
+      "clangModulePath": "INPUTSDIR/APINotesFrameworkTest.pcm"
+  }  
+]
+
+//--- client.swift
+import APINotesFrameworkTest
diff --git a/test/APINotes/broken-swift-name.swift b/test/APINotes/broken-swift-name.swift
index d866edd20efdc..d3d46baa2e91d 100644
--- a/test/APINotes/broken-swift-name.swift
+++ b/test/APINotes/broken-swift-name.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -I %S/Inputs/broken-modules
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs/broken-modules
 import BrokenAPINotes
 
 func testBrokenSwiftName(x: inout ZXSpectrum) {
diff --git a/test/APINotes/obsoleted.swift b/test/APINotes/obsoleted.swift
index 8a16502924a68..b484b7cf639fb 100644
--- a/test/APINotes/obsoleted.swift
+++ b/test/APINotes/obsoleted.swift
@@ -1,6 +1,6 @@
-// RUN: not %target-swift-frontend -typecheck -verify -I %S/Inputs/custom-modules -F %S/Inputs/custom-frameworks -swift-version 4 %s
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs/custom-modules -F %S/Inputs/custom-frameworks -swift-version 4.2 %s
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs/custom-modules -F %S/Inputs/custom-frameworks -swift-version 5 %s
+// RUN: not %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules -F %S/Inputs/custom-frameworks -swift-version 4 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules -F %S/Inputs/custom-frameworks -swift-version 4.2 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules -F %S/Inputs/custom-frameworks -swift-version 5 %s
 // REQUIRES: objc_interop
 import ObsoletedAPINotesTest
 
diff --git a/test/APINotes/version-independent.swift b/test/APINotes/version-independent.swift
new file mode 100644
index 0000000000000..46dc8a3b49eb1
--- /dev/null
+++ b/test/APINotes/version-independent.swift
@@ -0,0 +1,124 @@
+// REQUIRES: objc_interop
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/inputs)
+// RUN: %empty-directory(%t/ModuleCache)
+// RUN: %empty-directory(%t/Swift)
+// RUN: %empty-directory(%t/CFrameworks)
+// RUN: %empty-directory(%t/CFrameworks/Bar.framework)
+// RUN: %empty-directory(%t/CFrameworks/Bar.framework/Headers)
+// RUN: %empty-directory(%t/CFrameworks/Bar.framework/Modules)
+// RUN: split-file %s %t
+
+// 0. Fixup the input module file map
+// RUN: sed -e "s|INPUTSDIR|%/t/inputs|g" %t/input_map.json.template > %t/input_map.json.template1
+// RUN: sed -e "s|STDLIBMOD|%/stdlib_module|g" %t/input_map.json.template1 > %t/input_map.json.template2
+// RUN: sed -e "s|ONONEMOD|%/ononesupport_module|g" %t/input_map.json.template2 > %t/input_map.json.template3
+// RUN: sed -e "s|BARMOD|%t/inputs/Bar.pcm|g" %t/input_map.json.template3 > %t/input_map.json.template4
+// RUN: sed -e "s|BARMAP|%t/CFrameworks/Bar.framework/Modules/module.modulemap|g" %t/input_map.json.template4 > %t/input_map.json.template5
+// RUN: sed -e "s|FOOMOD|%/t/inputs/Foo.swiftmodule|g" %t/input_map.json.template5 > %t/input_map.json.template6
+// RUN: sed -e "s|SWIFTLIBDIR|%swift-lib-dir|g" %t/input_map.json.template6 > %t/input_map.json
+
+// 1. Build `Foo.swiftmodule` and `Foo.swiftinterface` using `-swift-version 5`
+// RUN: %target-swift-frontend -emit-module -F%t/CFrameworks %t/Foo.swift -emit-module-path %t/Swift/Foo.swiftmodule/%target-swiftmodule-name -module-name Foo -emit-module-interface-path %t/Swift/Foo.swiftmodule/%target-swiftinterface-name -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -module-cache-path %t/ModuleCache -enable-library-evolution -swift-version 5 -version-independent-apinotes
+
+// 2. Prepare for an explicit build of `Foo` and `main` by pre-compiling its dependencies
+// RUN: %target-swift-emit-pcm -module-name Bar -o %t/inputs/Bar.pcm %t/CFrameworks/Bar.framework/Modules/module.modulemap -Xcc -fswift-version-independent-apinotes
+// RUN: %target-swift-emit-pcm -module-name SwiftShims %swift-lib-dir/swift/shims/module.modulemap -o %t/inputs/SwiftShims.pcm -Xcc -fswift-version-independent-apinotes
+
+// 3. Build textual `Foo.swiftinterface` into a binary module using its interface-coded `-swift-version 5`
+// RUN: rm %t/Swift/Foo.swiftmodule/%target-swiftmodule-name
+// RUN: %target-swift-frontend -compile-module-from-interface %t/Swift/Foo.swiftmodule/%target-swiftinterface-name -o %t/inputs/Foo.swiftmodule -module-name Foo -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -disable-implicit-swift-modules -Xcc -fno-implicit-modules -Xcc -fno-implicit-module-maps -explicit-swift-module-map-file %t/input_map.json -swift-version 5 -version-independent-apinotes
+
+// 4. Build `main.swift` using `-swift-version 4`
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/Main.swiftmodule -disable-implicit-swift-modules -module-cache-path %t.module-cache -explicit-swift-module-map-file %t/input_map.json -swift-version 4 -version-independent-apinotes %t/main.swift -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import
+
+// Because the `Bar` Clang module gets built with `-fswift-version-independent-apinotes`, it encodes all versioned APINotes into the resulting PCM. This means that `Foo.swiftinterface`, which gets built with Swift version 5, is able to resolve references to `funcBro` in its inlinable code to Bar's `funcBar`, according to version 5 APINotes, and `main.swift` is able to resolve a reference to `funkBus` to Bar's `funcBaz`, according to version 4 APINotes. `main.swift` compilation also gets the APINotes that ensures that `barGlobal`'s type is `unsigned` rather than `int`, as it appears in the source, as per APINotes version 4.
+
+//--- CFrameworks/Bar.framework/Headers/Bar.h
+int barGlobal = 42;
+int funcBar(void) {
+  return 1;
+}
+int funcBaz(void) {
+  return 2;
+}
+int funcNuc(void) {
+  return 3;
+}
+
+//--- CFrameworks/Bar.framework/Headers/Bar.apinotes
+---
+Name: Bar
+SwiftVersions:
+- Version: 4.0
+  Functions:
+  - Name: funcBar
+    SwiftName: "funcBoom()"
+  - Name: funcBaz
+    SwiftName: "funkBus()"
+
+  Globals:
+  - Name: barGlobal
+    Type: "unsigned"
+
+- Version: 5.0
+  Functions:
+  - Name: funcBar
+    SwiftName: "funcBro()"
+  - Name: funcNuc
+    SwiftName: "funcNot()"
+
+Functions:
+  - Name: funcBar
+    SwiftName: "funcBroom()"
+
+//--- CFrameworks/Bar.framework/Modules/module.modulemap
+framework module Bar [system] {
+  header "Bar.h"
+  export *
+}
+
+//--- Foo.swift
+import Bar
+@inlinable
+public func foo() -> Int {
+    return Int(funcBro())
+}
+
+//--- main.swift
+import Foo
+import Bar
+
+let x: UInt32 = barGlobal
+print(41 + foo() + Int(funkBus()) + Int(funcNot()))
+
+//--- input_map.json.template
+[
+  {
+      "moduleName": "Swift",
+      "modulePath": "STDLIBMOD",
+      "isFramework": false
+  },
+  {
+      "moduleName": "SwiftOnoneSupport",
+      "modulePath": "ONONEMOD",
+      "isFramework": false
+  },
+  {
+      "moduleName": "Bar",
+      "isFramework": true,
+      "clangModuleMapPath": "BARMAP",
+      "clangModulePath": "BARMOD"
+  },
+  {
+      "moduleName": "Foo",
+      "modulePath": "FOOMOD",
+      "isFramework": true
+  },
+  {
+      "moduleName": "SwiftShims",
+      "isFramework": false,
+      "clangModuleMapPath": "SWIFTLIBDIR/swift/shims/module.modulemap",
+      "clangModulePath": "INPUTSDIR/SwiftShims.pcm"
+  }
+]
diff --git a/test/APINotes/versioned-test-mangling.swift b/test/APINotes/versioned-test-mangling.swift
index 212275310d6a5..87d157639480a 100644
--- a/test/APINotes/versioned-test-mangling.swift
+++ b/test/APINotes/versioned-test-mangling.swift
@@ -1,14 +1,24 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 4 -find-mangled '$sSo11SomeCStructV' | %FileCheck -check-prefix=CHECK-TOP-ALIAS-4 %s
-// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 5 -find-mangled '$sSo11SomeCStructV' | %FileCheck -check-prefix=CHECK-TOP-ALIAS-5 %s
+// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 4 -find-mangled '$sSo11SomeCStructV' | %FileCheck -check-prefix=CHECK-TOP-ALIAS-UNDERLYING-4 %s
+// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 5 -find-mangled '$sSo11SomeCStructV' | %FileCheck -check-prefix=CHECK-TOP-ALIAS-UNDERLYING-5 %s
 
-// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 4 -find-mangled '$sSo13InnerInSwift5V' | %FileCheck -check-prefix=CHECK-NESTED-ALIAS-4 %s
-// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 5 -find-mangled '$sSo13InnerInSwift5V' | %FileCheck -check-prefix=CHECK-NESTED-ALIAS-5 %s
+// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 4 -find-mangled '$sSo13InnerInSwift5V' | %FileCheck -check-prefix=CHECK-NESTED-ALIAS-UNDERLYING-4 %s
+// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 5 -find-mangled '$sSo13InnerInSwift5V' | %FileCheck -check-prefix=CHECK-NESTED-ALIAS-UNDERLYING-5 %s
+
+// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 4 -find-mangled '$sSC16ImportantCStructa' | %FileCheck -check-prefix=CHECK-TOP-ALIAS-SYNTHESIZED-4 %s
+// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 5 -find-mangled '$sSC16ImportantCStructa' | %FileCheck -check-prefix=CHECK-TOP-ALIAS-SYNTHESIZED-5 %s
+
+// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 4 -find-mangled '$sSC13InnerInSwift5a' | %FileCheck -check-prefix=CHECK-NESTED-ALIAS-SYNTHESIZED-4 %s
+// RUN: %target-swift-ide-test -F %S/Inputs/custom-frameworks -print-ast-typechecked -source-filename %s -swift-version 5 -find-mangled '$sSC13InnerInSwift5a' | %FileCheck -check-prefix=CHECK-NESTED-ALIAS-SYNTHESIZED-5 %s
 
 import APINotesFrameworkTest
 
-// CHECK-TOP-ALIAS-4: typealias ImportantCStruct = VeryImportantCStruct
-// CHECK-TOP-ALIAS-5: struct VeryImportantCStruct {
-// CHECK-NESTED-ALIAS-4: typealias InnerInSwift5 = Outer.Inner
-// CHECK-NESTED-ALIAS-5: struct Inner {
+// CHECK-TOP-ALIAS-UNDERLYING-4: struct VeryImportantCStruct {
+// CHECK-TOP-ALIAS-UNDERLYING-5: struct VeryImportantCStruct {
+// CHECK-NESTED-ALIAS-UNDERLYING-4: struct Inner {
+// CHECK-NESTED-ALIAS-UNDERLYING-5: struct Inner {
+// CHECK-TOP-ALIAS-SYNTHESIZED-4: typealias ImportantCStruct = VeryImportantCStruct
+// CHECK-TOP-ALIAS-SYNTHESIZED-5: typealias ImportantCStruct = VeryImportantCStruct
+// CHECK-NESTED-ALIAS-SYNTHESIZED-4: typealias InnerInSwift5 = Outer.Inner
+// CHECK-NESTED-ALIAS-SYNTHESIZED-5: typealias InnerInSwift5 = Outer.Inner
diff --git a/test/ASTGen/attrs.swift b/test/ASTGen/attrs.swift
index 307dd7770c3b1..7f3bca52c1ddf 100644
--- a/test/ASTGen/attrs.swift
+++ b/test/ASTGen/attrs.swift
@@ -1,24 +1,22 @@
 // RUN: %empty-directory(%t)
 
 // RUN: %target-swift-frontend-dump-parse \
-// RUN:   -enable-experimental-feature ABIAttribute \
-// RUN:   -enable-experimental-feature ExecutionAttribute \
 // RUN:   -enable-experimental-feature Extern \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-feature RawLayout \
 // RUN:   -enable-experimental-feature SymbolLinkageMarkers \
+// RUN:   -enable-experimental-feature CDecl \
 // RUN:   -enable-experimental-concurrency \
 // RUN:   -enable-experimental-move-only \
 // RUN:   -enable-experimental-feature ParserASTGen \
 // RUN:   | %sanitize-address > %t/astgen.ast
 
 // RUN: %target-swift-frontend-dump-parse \
-// RUN:   -enable-experimental-feature ABIAttribute \
-// RUN:   -enable-experimental-feature ExecutionAttribute \
 // RUN:   -enable-experimental-feature Extern \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-feature RawLayout \
 // RUN:   -enable-experimental-feature SymbolLinkageMarkers \
+// RUN:   -enable-experimental-feature CDecl \
 // RUN:   -enable-experimental-concurrency \
 // RUN:   -enable-experimental-move-only \
 // RUN:   | %sanitize-address > %t/cpp-parser.ast
@@ -28,25 +26,22 @@
 // RUN: %target-typecheck-verify-swift \
 // RUN:   -module-abi-name ASTGen \
 // RUN:   -enable-experimental-feature ParserASTGen \
-// RUN:   -enable-experimental-feature ABIAttribute \
-// RUN:   -enable-experimental-feature ExecutionAttribute \
 // RUN:   -enable-experimental-feature Extern \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-feature RawLayout \
 // RUN:   -enable-experimental-feature SymbolLinkageMarkers \
+// RUN:   -enable-experimental-feature CDecl \
 // RUN:   -enable-experimental-concurrency \
 // RUN:   -enable-experimental-move-only
 
 // REQUIRES: concurrency
-// REQUIRES: executable_test
 // REQUIRES: swift_swift_parser
 // REQUIRES: swift_feature_ParserASTGen
-// REQUIRES: swift_feature_ABIAttribute
-// REQUIRES: swift_feature_ExecutionAttribute
 // REQUIRES: swift_feature_Extern
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_RawLayout
 // REQUIRES: swift_feature_SymbolLinkageMarkers
+// REQUIRES: swift_feature_CDecl
 
 // rdar://116686158
 // UNSUPPORTED: asan
@@ -103,7 +98,9 @@ func fn(_: Int) {}
 
 @_disallowFeatureSuppression(NoncopyableGenerics) public struct LoudlyNC<T: ~Copyable> {}
 
-@_cdecl("c_function_name") func foo(x: Int) {}
+@_cdecl("c_function_name") func cdeclUnderscore(x: Int) {}
+@c(c_function_name_official) func cdecl(x: Int) {}
+@c func cdeclDefault() {}
 
 struct StaticProperties {
   dynamic var property: Int { return 1 }
@@ -178,6 +175,9 @@ struct ProjectedValueStruct {
 @_specialize(where X: _TrivialStride(16), Y: _Trivial(32, 4), Z: _Class)
 func testSpecialize<X, Y, Z>(x: X, y: Y, z: Z) {}
 
+@specialized(where X == Int, Y == Float, Z == Double)
+func testSpecializePublic<X, Y, Z>(x: X, y: Y, z: Z) {}
+
 @_spi(SPIName) public func spiFn() {}
 
 struct StorageRestrctionTest {
@@ -195,19 +195,19 @@ struct StorageRestrctionTest {
 @_unavailableFromAsync struct UnavailFromAsyncStruct { } // expected-error {{'@_unavailableFromAsync' attribute cannot be applied to this declaration}}
 @_unavailableFromAsync(message: "foo bar") func UnavailFromAsyncFn() {}
 
-@execution(concurrent) func testGlobal() async { // Ok
+@concurrent func testGlobal() async { // Ok
 }
 
 do {
-  @execution(caller) func testLocal() async {} // Ok
+  nonisolated(nonsending) func testLocal() async {} // Ok
 
   struct Test {
-    @execution(concurrent) func testMember() async {} // Ok
+    @concurrent func testMember() async {} // Ok
   }
 }
 
 typealias testConvention = @convention(c) (Int) -> Int
-typealias testExecution = @execution(concurrent) () async -> Void
+typealias testExecution = @concurrent () async -> Void
 typealias testIsolated = @isolated(any) () -> Void
 
 protocol OpProto {}
@@ -219,13 +219,13 @@ struct OpTest {
 
 struct E {}
 struct NE : ~Escapable {}
-@lifetime(copy ne) func derive(_ ne: NE) -> NE { ne }
-@lifetime(borrow ne1, copy ne2) func derive(_ ne1: NE, _ ne2: NE) -> NE {
+@_lifetime(copy ne) func derive(_ ne: NE) -> NE { ne }
+@_lifetime(borrow ne1, copy ne2) func derive(_ ne1: NE, _ ne2: NE) -> NE {
   if (Int.random(in: 1..<100) < 50) { return ne1 }
   return ne2
 }
-@lifetime(borrow borrow) func testNameConflict(_ borrow: E) -> NE { NE() }
-@lifetime(result: copy source) func testTarget(_ result: inout NE, _ source: consuming NE) { result = source }
+@_lifetime(borrow borrow) func testNameConflict(_ borrow: E) -> NE { NE() }
+@_lifetime(result: copy source) func testTarget(_ result: inout NE, _ source: consuming NE) { result = source }
 
 actor MyActor {
   nonisolated let constFlag: Bool = false
@@ -264,3 +264,6 @@ struct LayoutOuter {
 struct AnyEraser: EraserProto {
   init<T: EraserProto>(erasing: T) {}
 }
+
+func takeNone(@_inheritActorContext param: @Sendable () async -> ()) { }
+func takeAlways(@_inheritActorContext(always) param: sending @isolated(any) () -> ()) { }
diff --git a/test/ASTGen/attrs_objc.swift b/test/ASTGen/attrs_objc.swift
index 64f7e44e39142..fdb07cb7d8f6e 100644
--- a/test/ASTGen/attrs_objc.swift
+++ b/test/ASTGen/attrs_objc.swift
@@ -11,6 +11,7 @@
 // REQUIRES: swift_swift_parser
 // REQUIRES: objc_interop
 // REQUIRES: swift_feature_ParserASTGen
+// REQUIRES: string_processing
 
 @objc class MyCls {
   @objc(theValue) var value: Int { 1 }
diff --git a/test/ASTGen/availability.swift b/test/ASTGen/availability.swift
index 72077ec6a6c60..0da37363a8e2e 100644
--- a/test/ASTGen/availability.swift
+++ b/test/ASTGen/availability.swift
@@ -49,7 +49,7 @@ func testSpecialize<T>(arg: T) -> T {}
 public func testBackDeployed() {}
 
 @available(macOS 10, iOS 12, *)
-@_originallyDefinedIn(module: "OriginalModule", macOS 12.0, iOS 23.2)
+@_originallyDefinedIn(module: "OriginalModule", macOS 12.0, iOS 13.2)
 public func testOriginallyDefinedIn() {}
 
 
diff --git a/test/ASTGen/decls.swift b/test/ASTGen/decls.swift
index afa080b51c81e..aebef050c773d 100644
--- a/test/ASTGen/decls.swift
+++ b/test/ASTGen/decls.swift
@@ -2,19 +2,22 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend-dump-parse -disable-availability-checking -enable-experimental-move-only -enable-experimental-concurrency -enable-experimental-feature ParserASTGen \
 // RUN:    -enable-experimental-feature CoroutineAccessors \
+// RUN:    -enable-experimental-feature DefaultIsolationPerFile \
 // RUN:    | %sanitize-address > %t/astgen.ast
 // RUN: %target-swift-frontend-dump-parse -disable-availability-checking -enable-experimental-move-only -enable-experimental-concurrency \
 // RUN:    -enable-experimental-feature CoroutineAccessors \
+// RUN:    -enable-experimental-feature DefaultIsolationPerFile \
 // RUN:    | %sanitize-address > %t/cpp-parser.ast
 
 // RUN: %diff -u %t/astgen.ast %t/cpp-parser.ast
 
-// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -Xfrontend -enable-experimental-concurrency -enable-experimental-feature CoroutineAccessors -enable-experimental-feature ParserASTGen)
+// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -Xfrontend -enable-experimental-concurrency -enable-experimental-feature CoroutineAccessors -enable-experimental-feature DefaultIsolationPerFile -enable-experimental-feature ParserASTGen)
 
 // REQUIRES: executable_test
 // REQUIRES: swift_swift_parser
 // REQUIRES: swift_feature_ParserASTGen
 // REQUIRES: swift_feature_CoroutineAccessors
+// REQUIRES: swift_feature_DefaultIsolationPerFile
 
 // rdar://116686158
 // UNSUPPORTED: asan
@@ -31,6 +34,10 @@ import protocol Swift.Sequence
 import func Swift.max
 import var Swift._playgroundPrintHook
 
+
+using @MainActor
+// FIXME: cannot add `using nonisolated` here because it's a re-declaration
+
 func
 test1
 (
diff --git a/test/ASTGen/diagnostics.swift b/test/ASTGen/diagnostics.swift
index 58f9fafe5cbfe..056a8b87b06c4 100644
--- a/test/ASTGen/diagnostics.swift
+++ b/test/ASTGen/diagnostics.swift
@@ -1,9 +1,14 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-bare-slash-regex -enable-experimental-feature ParserASTGen
+// RUN: %target-typecheck-verify-swift -disable-availability-checking \
+// RUN:   -enable-bare-slash-regex \
+// RUN:   -enable-experimental-feature ParserASTGen \
+// RUN:   -enable-experimental-feature DefaultIsolationPerFile
 
 // REQUIRES: swift_swift_parser
 // REQUIRES: swift_feature_ParserASTGen
+// REQUIRES: swift_feature_DefaultIsolationPerFile
+
 // rdar://116686158
 // UNSUPPORTED: asan
 
@@ -16,6 +21,10 @@ func testRegexLiteral() {
 func testEditorPlaceholder() -> Int {
   func foo(_ x: String) {}
   foo(<#T##x: String##String#>) // expected-error {{editor placeholder in source file}})
+
+  // Make sure we don't try to parse this as an editor placeholder.
+  _ = `<#foo#>` // expected-error {{cannot find '<#foo#>' in scope}}
+
   return <#T##Int#> // expected-error {{editor placeholder in source file}}
 }
 
@@ -35,7 +44,7 @@ struct S {
 }
 
 struct ExpansionRequirementTest<each T> {}
-extension ExpansionRequirementTest where repeat each T == Int {} // expected-error {{same-element requirements are not yet supported}}
+extension ExpansionRequirementTest where repeat each T == Int {} // expected-error {{same-type requirements between packs and concrete types are not yet supported}}
 
 
 #warning("this is a warning") // expected-warning {{this is a warning}}
@@ -66,3 +75,12 @@ func misisngPatternTest(arr: [Int]) {
   for {} // expected-error {{expected pattern, 'in', and expression in 'for' statement}}
          // expected-note@-1 {{insert pattern, 'in', and expression}} {{7-7=<#pattern#> }} {{7-7=in }} {{7-7=<#expression#> }}
 }
+
+using @MainActor // expected-note {{default isolation was previously declared here}}
+using nonisolated // expected-error {{invalid redeclaration of file-level default actor isolation}}
+
+using @Test
+// expected-error@-1 {{default isolation can only be set to '@MainActor' or 'nonisolated'}}
+
+using test
+// expected-error@-1 {{default isolation can only be set to '@MainActor' or 'nonisolated'}}
diff --git a/test/ASTGen/embedded_availability.swift b/test/ASTGen/embedded_availability.swift
index e6f72429d81ac..a7de4b091dc22 100644
--- a/test/ASTGen/embedded_availability.swift
+++ b/test/ASTGen/embedded_availability.swift
@@ -11,7 +11,7 @@ public struct UnavailableInEmbedded {}
 
 @available(*, unavailable, message: "always unavailable")
 public struct UniverallyUnavailable {}
-// expected-note@-1 {{'UniverallyUnavailable' has been explicitly marked unavailable here}}
+// expected-note@-1 3 {{'UniverallyUnavailable' has been explicitly marked unavailable here}}
 
 @_unavailableInEmbedded
 public func unavailable_in_embedded() { }
@@ -43,7 +43,7 @@ public struct Available {}
 extension Available {
   public func unavailable_in_embedded_method( // expected-note {{'unavailable_in_embedded_method' has been explicitly marked unavailable here}}
     _ uie: UnavailableInEmbedded,
-    _ uu: UniverallyUnavailable,
+    _ uu: UniverallyUnavailable, // expected-error {{'UniverallyUnavailable' is unavailable: always unavailable}}
     _ a: Available,
   ) {
     unavailable_in_embedded()
@@ -67,7 +67,7 @@ public func available(
 @_unavailableInEmbedded
 public func also_unavailable_in_embedded(
   _ uie: UnavailableInEmbedded, // OK
-  _ uu: UniverallyUnavailable, // OK
+  _ uu: UniverallyUnavailable, // expected-error {{'UniverallyUnavailable' is unavailable: always unavailable}}
   _ a: Available,
 ) {
   unavailable_in_embedded() // OK
diff --git a/test/ASTGen/if_config_expr.swift b/test/ASTGen/if_config_expr.swift
index 32b5c2bd33cb2..11c92997ca4cd 100644
--- a/test/ASTGen/if_config_expr.swift
+++ b/test/ASTGen/if_config_expr.swift
@@ -46,7 +46,7 @@ func testInvalidContent(baseExpr: MyStruct, otherExpr: Int) {
 
   baseExpr      // expected-warning {{expression of type 'MyStruct' is unused}}
 #if CONDITION_1
-    + otherExpr // expected-error {{unexpected code '+ otherExpr' in conditional compilation block}}
+    + otherExpr // expected-error {{unexpected code '+ otherExpr' in conditional compilation clause}}
 #endif
 
   baseExpr
diff --git a/test/ASTGen/types.swift b/test/ASTGen/types.swift
index 1ee9cd362392d..3af33a56e512f 100644
--- a/test/ASTGen/types.swift
+++ b/test/ASTGen/types.swift
@@ -2,22 +2,18 @@
 
 // RUN: %target-swift-frontend-dump-parse -enable-experimental-feature ParserASTGen \
 // RUN:   -enable-experimental-feature NamedOpaqueTypes \
-// RUN:   -enable-experimental-feature InlineArrayTypeSugar \
 // RUN:   | %sanitize-address > %t/astgen.ast
 // RUN: %target-swift-frontend-dump-parse \
 // RUN:   -enable-experimental-feature NamedOpaqueTypes \
-// RUN:   -enable-experimental-feature InlineArrayTypeSugar \
 // RUN:   | %sanitize-address > %t/cpp-parser.ast
 
 // RUN: %diff -u %t/astgen.ast %t/cpp-parser.ast
 
 // RUN: %target-typecheck-verify-swift -enable-experimental-feature ParserASTGen \
-// RUN:   -enable-experimental-feature NamedOpaqueTypes \
-// RUN:   -enable-experimental-feature InlineArrayTypeSugar
+// RUN:   -enable-experimental-feature NamedOpaqueTypes
 
 // REQUIRES: swift_feature_ParserASTGen
 // REQUIRES: swift_feature_NamedOpaqueTypes
-// REQUIRES: swift_feature_InlineArrayTypeSugar
 
 // rdar://116686158
 // UNSUPPORTED: asan
@@ -84,10 +80,10 @@ let optionalIntArray: Array<_> = [42]
 
 @available(SwiftStdlib 9999, *)
 func testInlineArray() {
-  let _: [3 x Int] = [1, 2, 3]
-  let _: [_ x _] = [1, 2]
-  let _ = [3 x Int](repeating: 0)
-  let _ = [3 x _](repeating: 0)
+  let _: [3 of Int] = [1, 2, 3]
+  let _: [_ of _] = [1, 2]
+  let _ = [3 of Int](repeating: 0)
+  let _ = [3 of _](repeating: 0)
 }
 
 func testNamedOpaqueReturnTy() -> <T> T { return () }
diff --git a/test/AssociatedTypeInference/issue-79367.swift b/test/AssociatedTypeInference/issue-79367.swift
new file mode 100644
index 0000000000000..ad4a7c01adb0e
--- /dev/null
+++ b/test/AssociatedTypeInference/issue-79367.swift
@@ -0,0 +1,15 @@
+// RUN: %target-typecheck-verify-swift
+
+// https://github.com/swiftlang/swift/issues/79367
+
+// 'Failure' type witness inference should still take place when
+// the 'next()' witness is in a different extension than the
+// conformance.
+
+struct AsyncIteratorImpl<Element>: AsyncIteratorProtocol {}
+
+extension AsyncIteratorImpl {
+  func next() async throws -> Element? {
+    fatalError()
+  }
+}
diff --git a/test/AssociatedTypeInference/missing_conformance.swift b/test/AssociatedTypeInference/missing_conformance.swift
index 690b79bd2ff05..ed74447b751a4 100644
--- a/test/AssociatedTypeInference/missing_conformance.swift
+++ b/test/AssociatedTypeInference/missing_conformance.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // Test candidates for witnesses that are missing conformances
 // in various ways.
diff --git a/test/AssociatedTypeInference/rdar127575477.swift b/test/AssociatedTypeInference/rdar127575477.swift
index 202d3933768e1..b2c0ccc5988db 100644
--- a/test/AssociatedTypeInference/rdar127575477.swift
+++ b/test/AssociatedTypeInference/rdar127575477.swift
@@ -1,4 +1,4 @@
-// RUN: not %target-typecheck-verify-swift
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // This is highly invalid, so just don't crash.
 
diff --git a/test/AssociatedTypeInference/type_witness_from_parameterized_protocol.swift b/test/AssociatedTypeInference/type_witness_from_parameterized_protocol.swift
new file mode 100644
index 0000000000000..81aff5087217a
--- /dev/null
+++ b/test/AssociatedTypeInference/type_witness_from_parameterized_protocol.swift
@@ -0,0 +1,56 @@
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
+
+protocol P<A, B> {
+  associatedtype A  // expected-note {{multiple matching types named 'A'}}
+  associatedtype B
+
+  func a(_: A)
+}
+
+extension P {
+  func a(_: A) {}
+}
+
+struct S: P<Int, String> {}
+
+func f(_: Int.Type) {}
+func g(_: String.Type) {}
+
+f(S.A.self)
+g(S.B.self)
+
+struct G<T, U>: P<T, U> {}
+
+f(G<Int, String>.A.self)
+g(G<Int, String>.B.self)
+
+protocol Q<B> {
+  associatedtype B  // expected-note {{protocol requires nested type 'B'}}
+}
+
+struct S2: P, Q<String> {
+  func a(_: Int) {}
+}
+
+struct S3: P & Q<String> {
+  func a(_: Int) {}
+}
+
+protocol R {}
+
+struct S4: (P & Q<String>) & R {
+  func a(_: Int) {}
+}
+
+struct Bad: P<Int, Float> { // expected-error {{type 'Bad' does not conform to protocol 'P'}}
+  typealias A = String  // expected-note {{possibly intended match}}
+}
+
+let x = Bad.A.self
+g(x)
+
+struct Circle: Q<Circle.A> {}
+// expected-note@-1 {{'Circle' declared here}}
+// expected-error@-2 {{type 'Circle' does not conform to protocol 'Q'}}
+// expected-note@-3 {{add stubs for conformance}}
+// expected-error@-4 {{'A' is not a member type of struct 'type_witness_from_parameterized_protocol.Circle'}}
\ No newline at end of file
diff --git a/test/AutoDiff/IRGen/differentiable_function.sil b/test/AutoDiff/IRGen/differentiable_function.sil
index 9acbeef82cd5a..9d0b776e03966 100644
--- a/test/AutoDiff/IRGen/differentiable_function.sil
+++ b/test/AutoDiff/IRGen/differentiable_function.sil
@@ -33,7 +33,7 @@ bb0:
   return %result : $@differentiable(reverse) @callee_guaranteed (Float) -> Float
 }
 
-// CHECK-LABEL: define{{.*}}test_form_diff_func(ptr noalias nocapture sret(<{ %swift.function, %swift.function, %swift.function }>)
+// CHECK-LABEL: define{{.*}}test_form_diff_func(ptr noalias{{( nocapture)?}} sret(<{ %swift.function, %swift.function, %swift.function }>)
 // CHECK-SAME: [[OUT:%.*]])
 // CHECK:   [[OUT_ORIG:%.*]] = getelementptr{{.*}}[[OUT]], i32 0, i32 0
 // CHECK:   [[OUT_ORIG_FN:%.*]] = getelementptr{{.*}}[[OUT_ORIG]], i32 0, i32 0
@@ -60,7 +60,7 @@ bb0(%0 : $@differentiable(reverse) @callee_guaranteed (Float) -> Float):
   return %result : $(@callee_guaranteed (Float) -> Float, @callee_guaranteed (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float), @callee_guaranteed (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float))
 }
 
-// CHECK-LABEL: define{{.*}}@test_extract_components(ptr noalias nocapture sret(<{ %swift.function, %swift.function, %swift.function }>)
+// CHECK-LABEL: define{{.*}}@test_extract_components(ptr noalias{{( nocapture)?}} sret(<{ %swift.function, %swift.function, %swift.function }>)
 // CHECK-SAME: [[OUT:%.*]], ptr{{.*}}[[IN:%.*]])
 // CHECK:   [[ORIG:%.*]] = getelementptr{{.*}}[[IN]], i32 0, i32 0
 // CHECK:   [[ORIG_FN_ADDR:%.*]] = getelementptr{{.*}}[[ORIG]], i32 0, i32 0
diff --git a/test/AutoDiff/SIL/differentiability_witness_function_inst.sil b/test/AutoDiff/SIL/differentiability_witness_function_inst.sil
index 9318d934a9faf..0e702cd253122 100644
--- a/test/AutoDiff/SIL/differentiability_witness_function_inst.sil
+++ b/test/AutoDiff/SIL/differentiability_witness_function_inst.sil
@@ -95,14 +95,14 @@ bb0:
 
 // IRGEN: [[PTR1:%.*]] = load ptr, ptr @fooWJrSUUpSr, align [[PTR_ALIGNMENT]]
 
-// IRGEN: [[PTR2:%.*]] = load ptr, ptr getelementptr inbounds (%swift.differentiability_witness, ptr @fooWJrSSUpSr, i32 0, i32 1), align [[PTR_ALIGNMENT]]
+// IRGEN: [[PTR2:%.*]] = load ptr, ptr getelementptr inbounds{{.*}} (%swift.differentiability_witness, ptr @fooWJrSSUpSr, i32 0, i32 1), align [[PTR_ALIGNMENT]]
 
 // IRGEN: [[PTR3:%.*]] = load ptr, ptr @barWJrSUUpSUr, align [[PTR_ALIGNMENT]]
 
-// IRGEN: [[PTR4:%.*]] = load ptr, ptr getelementptr inbounds (%swift.differentiability_witness, ptr @barWJrSSUpSSr, i32 0, i32 1), align [[PTR_ALIGNMENT]]
+// IRGEN: [[PTR4:%.*]] = load ptr, ptr getelementptr inbounds{{.*}} (%swift.differentiability_witness, ptr @barWJrSSUpSSr, i32 0, i32 1), align [[PTR_ALIGNMENT]]
 
 // IRGEN: [[PTR5:%.*]] = load ptr, ptr @generic16_Differentiation14DifferentiableRzlWJrSUpSr, align [[PTR_ALIGNMENT]]
 
-// IRGEN: [[PTR6:%.*]] = load ptr, ptr getelementptr inbounds (%swift.differentiability_witness, ptr @generics18AdditiveArithmeticRz16_Differentiation14DifferentiableRzlWJrSSpSr, i32 0, i32 1), align [[PTR_ALIGNMENT]]
+// IRGEN: [[PTR6:%.*]] = load ptr, ptr getelementptr inbounds{{.*}} (%swift.differentiability_witness, ptr @generics18AdditiveArithmeticRz16_Differentiation14DifferentiableRzlWJrSSpSr, i32 0, i32 1), align [[PTR_ALIGNMENT]]
 
-// IRGEN: [[PTR7:%.*]] = load ptr, ptr getelementptr inbounds (%swift.differentiability_witness, ptr @generic16_Differentiation14DifferentiableRz13TangentVector{{.*}}WJrSSpSr, i32 0, i32 1), align [[PTR_ALIGNMENT]]
+// IRGEN: [[PTR7:%.*]] = load ptr, ptr getelementptr inbounds{{.*}} (%swift.differentiability_witness, ptr @generic16_Differentiation14DifferentiableRz13TangentVector{{.*}}WJrSSpSr, i32 0, i32 1), align [[PTR_ALIGNMENT]]
diff --git a/test/AutoDiff/SILGen/nil_coalescing.swift b/test/AutoDiff/SILGen/nil_coalescing.swift
index 027367e60d196..079d2d4747147 100644
--- a/test/AutoDiff/SILGen/nil_coalescing.swift
+++ b/test/AutoDiff/SILGen/nil_coalescing.swift
@@ -1,8 +1,9 @@
-// RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-sil -verify %s | %FileCheck %s
+/// Note: -primary-file prevents non_abi->shared linkage change in `removeSerializedFlagFromAllFunctions`
+// RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-sil -verify -primary-file %s | %FileCheck %s
 
 import _Differentiation
 
-// CHECK: sil @test_nil_coalescing
+// CHECK: sil non_abi @test_nil_coalescing
 // CHECK: bb0(%{{.*}} : $*T, %[[ARG_OPT:.*]] : $*Optional<T>, %[[ARG_PB:.*]] :
 // CHECK:    $@noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <T>):
 // CHECK: %[[ALLOC_OPT:.*]] = alloc_stack [lexical] $Optional<T>
@@ -15,7 +16,7 @@ import _Differentiation
 //
 @_silgen_name("test_nil_coalescing")
 @derivative(of: ??)
-@usableFromInline
+@_alwaysEmitIntoClient
 func nilCoalescing<T: Differentiable>(optional: T?, defaultValue: @autoclosure () throws -> T)
  rethrows -> (value: T, pullback: (T.TangentVector) -> Optional<T>.TangentVector)
 {
diff --git a/test/AutoDiff/SILOptimizer/BuildingSimulation.swift b/test/AutoDiff/SILOptimizer/BuildingSimulation.swift
new file mode 100644
index 0000000000000..b0b0dfd2f0d88
--- /dev/null
+++ b/test/AutoDiff/SILOptimizer/BuildingSimulation.swift
@@ -0,0 +1,228 @@
+// RUN: %target-swift-frontend -emit-sil -verify -O %s | %FileCheck %s
+// REQUIRES: swift_in_compiler
+
+import _Differentiation
+
+// Simulation parameters
+let trials = 100
+let timesteps = 20
+let dTime: Float = 0.1
+
+// Definitions
+let π = Float.pi
+
+struct SimParams: Differentiable {
+    var tube: TubeType = .init()
+    var slab: SlabType = .init()
+    var quanta: QuantaType = .init()
+    var tank: TankType = .init()
+    var startingTemp: Float
+}
+
+struct TubeType: Differentiable {
+    var tubeSpacing: Float = 0.50292 // meters
+    var diameter: Float = 0.019 // m  (3/4")
+    var thickness: Float = 0.001588 // m (1/16")
+    var resistivity: Float = 2.43 // (K/W)m
+}
+
+struct SlabType: Differentiable {
+    var temp: Float = 21.1111111 // °C
+    var area: Float = 100.0 // m^2
+    var Cp: Float = 0.2
+    var density: Float = 2242.58 // kg/m^3
+    var thickness: Float = 0.101 // m
+}
+
+struct QuantaType: Differentiable {
+    var power: Float = 0.0 // Watt
+    var temp: Float = 60.0 // °C
+    var flow: Float = 0.0006309 // m^3/sec
+    var density: Float = 1000.0 // kg/m^3
+    var Cp: Float = 4180.0 // ws/(kg • K)
+}
+
+struct TankType: Differentiable {
+    var temp: Float = 70.0
+    var volume: Float = 0.0757082
+    var Cp: Float = 4180.000
+    var density: Float = 1000.000
+    var mass: Float = 75.708
+}
+
+// Computations
+
+@differentiable(reverse)
+func computeResistance(floor: SlabType, tube: TubeType, quanta _: QuantaType) -> Float {
+    let geometry_coeff: Float = 10.0
+    // let f_coff = 0.3333333
+
+    let tubingSurfaceArea = (floor.area / tube.tubeSpacing) * π * tube.diameter
+    let resistance_abs = tube.resistivity * tube.thickness / tubingSurfaceArea
+
+    let resistance_corrected = resistance_abs * geometry_coeff // * (quanta.flow * f_coff)
+
+    return resistance_corrected
+}
+
+struct QuantaAndPower: Differentiable {
+    var quanta: QuantaType
+    var power: Float
+}
+
+
+extension Differentiable {
+    /// Applies the given closure to the derivative of `self`.
+    ///
+    /// Returns `self` like an identity function. When the return value is used in
+    /// a context where it is differentiated with respect to, applies the given
+    /// closure to the derivative of the return value.
+    @inlinable
+    @differentiable(reverse, wrt: self)
+    func withDerivative(_: @escaping (inout TangentVector) -> Void) -> Self {
+        return self
+    }
+
+    @inlinable
+    @derivative(of: withDerivative)
+    func _vjpWithDerivative(
+        _ body: @escaping (inout TangentVector) -> Void
+    ) -> (value: Self, pullback: (TangentVector) -> TangentVector) {
+        return (self, { grad in
+            var grad = grad
+            body(&grad)
+            return grad
+        })
+    }
+}
+
+@differentiable(reverse)
+func computeLoadPower(floor: SlabType, tube: TubeType, quanta: QuantaType) -> QuantaAndPower {
+    let resistance_abs = computeResistance(floor: floor, tube: tube, quanta: quanta)
+
+    let conductance: Float = 1 / resistance_abs
+    let dTemp = floor.temp - quanta.temp
+    let power = dTemp * conductance
+
+    var updatedQuanta = quanta
+    updatedQuanta.power = power
+    let loadPower = -power
+
+    return QuantaAndPower(quanta: updatedQuanta, power: loadPower)
+}
+
+@differentiable(reverse)
+func updateQuanta(quanta: QuantaType) -> QuantaType {
+    let workingVolume = (quanta.flow * dTime)
+    let workingMass = (workingVolume * quanta.density)
+    let workingEnergy = quanta.power * dTime
+    let TempRise = workingEnergy / quanta.Cp / workingMass
+    var updatedQuanta = quanta
+    updatedQuanta.temp = quanta.temp + TempRise
+
+    updatedQuanta.power = 0
+    return updatedQuanta
+}
+
+@differentiable(reverse)
+func updateBuildingModel(power: Float, floor: SlabType) -> SlabType {
+    var updatedFloor = floor
+
+    let floorVolume = floor.area * floor.thickness
+    let floorMass = floorVolume * floor.density
+
+    updatedFloor.temp = floor.temp + ((power * dTime) / floor.Cp / floorMass)
+    return updatedFloor
+}
+
+struct TankAndQuanta: Differentiable {
+    var tank: TankType
+    var quanta: QuantaType
+}
+
+@differentiable(reverse)
+func updateSourceTank(store: TankType, quanta: QuantaType) -> TankAndQuanta {
+    var updatedStore = store
+    var updatedQuanta = quanta
+
+    let massPerTime = quanta.flow * quanta.density
+    let dTemp = store.temp - quanta.temp
+    let power = dTemp * massPerTime * quanta.Cp
+
+    updatedQuanta.power = power
+
+    let tankMass = store.volume * store.density
+    let TempRise = (power * dTime) / store.Cp / tankMass
+    updatedStore.temp = store.temp + TempRise
+
+    return TankAndQuanta(tank: updatedStore, quanta: updatedQuanta)
+}
+
+var simParams = SimParams(startingTemp: 33.3)
+
+@differentiable(reverse)
+@inlinable public func absDifferentiable(_ value: Float) -> Float {
+    if value < 0 {
+        return -value
+    }
+    return value
+}
+
+func lossCalc(pred: Float, gt: Float) -> Float {
+    let diff = pred - gt
+    return absDifferentiable(diff)
+}
+
+// Simulations
+
+// Ensure things are properly specialized
+// CHECK-LABEL: sil hidden @$s18BuildingSimulation8simulate9simParamsSfAA03SimE0V_tFTJrSpSr
+// CHECK: function_ref specialized pullback of updateSourceTank(store:quanta:)
+// CHECK-NOT: function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
+// CHECK-NOT: function_ref pullback of updateQuanta(quanta:)
+// CHECK: function_ref specialized pullback of updateQuanta(quanta:)
+@differentiable(reverse)
+func simulate(simParams: SimParams) -> Float {
+    let pexTube = simParams.tube
+    var slab = simParams.slab
+    var tank = simParams.tank
+    var quanta = simParams.quanta
+
+    slab.temp = simParams.startingTemp
+    for _ in 0 ..< timesteps {
+        let tankAndQuanta = updateSourceTank(store: tank, quanta: quanta)
+        tank = tankAndQuanta.tank
+        quanta = tankAndQuanta.quanta
+
+        quanta = updateQuanta(quanta: quanta)
+
+        let quantaAndPower = computeLoadPower(floor: slab, tube: pexTube, quanta: quanta)
+        quanta = quantaAndPower.quanta
+        let powerToBuilding = quantaAndPower.power
+        quanta = updateQuanta(quanta: quanta)
+
+        slab = updateBuildingModel(power: powerToBuilding, floor: slab)
+    }
+    return slab.temp
+}
+
+var blackHole: Any?
+@inline(never)
+func dontLetTheCompilerOptimizeThisAway<T>(_ x: T) {
+    blackHole = x
+}
+
+@differentiable(reverse)
+func fullPipe(simParams: SimParams) -> Float {
+    let pred = simulate(simParams: simParams)
+    let loss = lossCalc(pred: pred, gt: 27.344767)
+    return loss
+}
+
+for _ in 0 ..< trials {
+    let forwardOnly = fullPipe(simParams: simParams)
+    dontLetTheCompilerOptimizeThisAway(forwardOnly)
+
+    let grad = gradient(at: simParams, of: fullPipe)
+    dontLetTheCompilerOptimizeThisAway(grad)
+}
diff --git a/test/AutoDiff/SILOptimizer/activity_analysis.swift b/test/AutoDiff/SILOptimizer/activity_analysis.swift
index d57583cbfe487..c29cdd99ad83a 100644
--- a/test/AutoDiff/SILOptimizer/activity_analysis.swift
+++ b/test/AutoDiff/SILOptimizer/activity_analysis.swift
@@ -798,7 +798,7 @@ func testActiveOptional(_ x: Float) -> Float {
 // CHECK: [NONE]   // function_ref _diagnoseUnexpectedNilOptional(_filenameStart:_filenameLength:_filenameIsASCII:_line:_isImplicitUnwrap:)
 // CHECK: [NONE]   %24 = apply %23(%17, %18, %19, %20, %22) : $@convention(thin) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, Builtin.Word, Builtin.Int1) -> ()
 // CHECK: bb2:
-// CHECK: [ACTIVE] %26 = argument of bb2 : $Float
+// CHECK: [ACTIVE] {{%[0-9]+}} = argument of bb2 : $Float
 
 enum DirectEnum: Differentiable & AdditiveArithmetic {
   case case0
diff --git a/test/AutoDiff/SILOptimizer/closure_specialization.sil b/test/AutoDiff/SILOptimizer/closure_specialization.sil
deleted file mode 100644
index 3d7c7ade772f2..0000000000000
--- a/test/AutoDiff/SILOptimizer/closure_specialization.sil
+++ /dev/null
@@ -1,509 +0,0 @@
-// RUN: %target-sil-opt -sil-print-types -test-runner %s -o /dev/null 2>&1 | %FileCheck %s
-
-// REQUIRES: swift_in_compiler
-
-sil_stage canonical
-
-import Builtin
-import Swift
-import SwiftShims
-
-import _Differentiation
-
-////////////////////////////////////////////////////////////////
-// Single closure call site where closure is passed as @owned //
-////////////////////////////////////////////////////////////////
-sil @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-
-sil private @$pullback_f : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float {
-bb0(%0 : $Float, %1 : $@callee_guaranteed (Float) -> (Float, Float)):
-  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> (Float, Float) 
-  strong_release %1 : $@callee_guaranteed (Float) -> (Float, Float) // id: %3
-  %4 = tuple_extract %2 : $(Float, Float), 0      
-  %5 = tuple_extract %2 : $(Float, Float), 1      
-  %6 = struct_extract %5 : $Float, #Float._value  
-  %7 = struct_extract %4 : $Float, #Float._value  
-  %8 = builtin "fadd_FPIEEE32"(%6 : $Builtin.FPIEEE32, %7 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  %9 = struct $Float (%8 : $Builtin.FPIEEE32)     
-  debug_value %9 : $Float, let, name "x", argno 1 // id: %10
-  return %9 : $Float                              // id: %11
-}
-
-// reverse-mode derivative of f(_:)
-sil hidden @$s4test1fyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
-bb0(%0 : $Float):
-  //=========== Test callsite and closure gathering logic ===========//
-  specify_test "closure_specialize_gather_call_sites"
-  // CHECK-LABEL: Specializing closures in function: $s4test1fyS2fFTJrSpSr
-  // CHECK: PartialApply call site:   %8 = partial_apply [callee_guaranteed] %7(%6) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float 
-  // CHECK: Passed in closures:
-  // CHECK: 1.   %6 = partial_apply [callee_guaranteed] %5(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-
-
- //=========== Test specialized function signature and body ===========//
-  specify_test "closure_specialize_specialized_function_signature_and_body"
-  // CHECK-LABEL: Generated specialized function: $s11$pullback_f12$vjpMultiplyS2fTf1nc_n
-  // CHECK: sil private @$s11$pullback_f12$vjpMultiplyS2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float {
-  // CHECK: bb0(%0 : $Float, %1 : $Float, %2 : $Float):
-  // CHECK: %3 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK: %4 = partial_apply [callee_guaranteed] %3(%1, %2) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK: %5 = apply %4(%0) : $@callee_guaranteed (Float) -> (Float, Float) 
-  // CHECK: strong_release %4 : $@callee_guaranteed (Float) -> (Float, Float) // id: %6
-  // CHECK: return
-
-   //=========== Test rewritten body ===========//
-  specify_test "closure_specialize_rewritten_caller_body"
-  // CHECK-LABEL: Rewritten caller body for: $s4test1fyS2fFTJrSpSr
-  // CHECK: sil hidden @$s4test1fyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {                                 
-  // CHECK: bb0(%0 : $Float):
-  // CHECK: %2 = struct_extract %0 : $Float, #Float._value  
-  // CHECK: %3 = builtin "fmul_FPIEEE32"(%2 : $Builtin.FPIEEE32, %2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  // CHECK: %4 = struct $Float (%3 : $Builtin.FPIEEE32)     
-  // CHECK: %5 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK: %6 = partial_apply [callee_guaranteed] %5(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK: %8 = function_ref @$s11$pullback_f12$vjpMultiplyS2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float 
-  // CHECK: %9 = partial_apply [callee_guaranteed] %8(%0, %0) : $@convention(thin) (Float, Float, Float) -> Float 
-  // CHECK: release_value %6 : $@callee_guaranteed (Float) -> (Float, Float) // id: %10
-  // CHECK: %11 = tuple (%4 : $Float, %9 : $@callee_guaranteed (Float) -> Float) 
-  // CHECK: return %11
-
-  debug_value %0 : $Float, let, name "x", argno 1 // id: %1
-  %2 = struct_extract %0 : $Float, #Float._value  
-  %3 = builtin "fmul_FPIEEE32"(%2 : $Builtin.FPIEEE32, %2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  %4 = struct $Float (%3 : $Builtin.FPIEEE32)     
-  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
-  %5 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  %6 = partial_apply [callee_guaranteed] %5(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // function_ref pullback of f(_:)
-  %7 = function_ref @$pullback_f : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float 
-  %8 = partial_apply [callee_guaranteed] %7(%6) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float 
-  %9 = tuple (%4 : $Float, %8 : $@callee_guaranteed (Float) -> Float) 
-  return %9 : $(Float, @callee_guaranteed (Float) -> Float) // id: %10
-}
-
-/////////////////////////////////////////////////////////////////////
-// Single closure call site where closure is passed as @guaranteed //
-/////////////////////////////////////////////////////////////////////
-sil private @$pullback_k : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float {
-// %0                                             
-// %1                                             
-bb0(%0 : $Float, %1 : $@callee_guaranteed (Float) -> (Float, Float)):
-  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> (Float, Float) 
-  %3 = tuple_extract %2 : $(Float, Float), 0      
-  %4 = tuple_extract %2 : $(Float, Float), 1      
-  %5 = struct_extract %4 : $Float, #Float._value  
-  %6 = struct_extract %3 : $Float, #Float._value  
-  %7 = builtin "fadd_FPIEEE32"(%5 : $Builtin.FPIEEE32, %6 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  %8 = struct $Float (%7 : $Builtin.FPIEEE32)     
-  debug_value %8 : $Float, let, name "x", argno 1 // id: %9
-  return %8 : $Float                              // id: %10
-} // end sil function '$pullback_k'
-
-// reverse-mode derivative of k(_:)
-sil hidden @$s4test1kyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
-bb0(%0 : $Float):
-  //=========== Test callsite and closure gathering logic ===========//
-  specify_test "closure_specialize_gather_call_sites"
-  // CHECK-LABEL: Specializing closures in function: $s4test1kyS2fFTJrSpSr
-  // CHECK: PartialApply call site:   %8 = partial_apply [callee_guaranteed] %7(%6) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float 
-  // CHECK: Passed in closures:
-  // CHECK: 1.   %6 = partial_apply [callee_guaranteed] %5(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-
-
- //=========== Test specialized function signature and body ===========//
-  specify_test "closure_specialize_specialized_function_signature_and_body"
-  // CHECK-LABEL: Generated specialized function: $s11$pullback_k12$vjpMultiplyS2fTf1nc_n
-  // CHECK: sil private @$s11$pullback_k12$vjpMultiplyS2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float {
-  // CHECK: bb0(%0 : $Float, %1 : $Float, %2 : $Float):
-  // CHECK:   %3 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK:   %4 = partial_apply [callee_guaranteed] %3(%1, %2) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK:   %5 = apply %4(%0) : $@callee_guaranteed (Float) -> (Float, Float) 
-  // CHECK:   release_value %4 : $@callee_guaranteed (Float) -> (Float, Float) // id: %13
-  // CHECK:   return %11
-
-   //=========== Test rewritten body ===========//
-  specify_test "closure_specialize_rewritten_caller_body"
-  // CHECK-LABEL: Rewritten caller body for: $s4test1kyS2fFTJrSpSr
-  // CHECK: sil hidden @$s4test1kyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {                                 
-  // CHECK: bb0(%0 : $Float):
-  // CHECK: %2 = struct_extract %0 : $Float, #Float._value  
-  // CHECK: %3 = builtin "fmul_FPIEEE32"(%2 : $Builtin.FPIEEE32, %2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  // CHECK: %4 = struct $Float (%3 : $Builtin.FPIEEE32)
-  // CHECK: %5 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float)
-  // CHECK: %6 = partial_apply [callee_guaranteed] %5(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
-  // CHECK: %8 = function_ref @$s11$pullback_k12$vjpMultiplyS2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float 
-  // CHECK: %9 = partial_apply [callee_guaranteed] %8(%0, %0) : $@convention(thin) (Float, Float, Float) -> Float 
-  // CHECK: strong_release %6 : $@callee_guaranteed (Float) -> (Float, Float)
-  // CHECK: %11 = tuple (%4 : $Float, %9 : $@callee_guaranteed (Float) -> Float) 
-  // CHECK: return %11
-
-  debug_value %0 : $Float, let, name "x", argno 1 // id: %1
-  %2 = struct_extract %0 : $Float, #Float._value  
-  %3 = builtin "fmul_FPIEEE32"(%2 : $Builtin.FPIEEE32, %2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  %4 = struct $Float (%3 : $Builtin.FPIEEE32)     
-  // function_ref $vjpMultiply
-  %5 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  %6 = partial_apply [callee_guaranteed] %5(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // function_ref $pullback_k
-  %7 = function_ref @$pullback_k : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float 
-  %8 = partial_apply [callee_guaranteed] %7(%6) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float 
-  strong_release %6 : $@callee_guaranteed (Float) -> (Float, Float) // id: %9
-  %10 = tuple (%4 : $Float, %8 : $@callee_guaranteed (Float) -> Float) 
-  return %10 : $(Float, @callee_guaranteed (Float) -> Float) // id: %11
-} // end sil function '$s4test1kyS2fFTJrSpSr'
-
-///////////////////////////////
-// Multiple closure callsite //
-///////////////////////////////
-sil @$vjpSin : $@convention(thin) (Float, Float) -> Float 
-sil @$vjpCos : $@convention(thin) (Float, Float) -> Float 
-
-// pullback of g(_:)
-sil private @$pullback_g : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float {
-bb0(%0 : $Float, %1 : $@callee_guaranteed (Float) -> Float, %2 : $@callee_guaranteed (Float) -> Float, %3 : $@callee_guaranteed (Float) -> (Float, Float)):
-  %4 = apply %3(%0) : $@callee_guaranteed (Float) -> (Float, Float) 
-  strong_release %3 : $@callee_guaranteed (Float) -> (Float, Float) // id: %5
-  %6 = tuple_extract %4 : $(Float, Float), 0      
-  %7 = tuple_extract %4 : $(Float, Float), 1      
-  %8 = apply %2(%7) : $@callee_guaranteed (Float) -> Float 
-  strong_release %2 : $@callee_guaranteed (Float) -> Float // id: %9
-  %10 = apply %1(%6) : $@callee_guaranteed (Float) -> Float 
-  strong_release %1 : $@callee_guaranteed (Float) -> Float // id: %11
-  %12 = struct_extract %8 : $Float, #Float._value 
-  %13 = struct_extract %10 : $Float, #Float._value 
-  %14 = builtin "fadd_FPIEEE32"(%13 : $Builtin.FPIEEE32, %12 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  %15 = struct $Float (%14 : $Builtin.FPIEEE32)   
-  debug_value %15 : $Float, let, name "x", argno 1 // id: %16
-  return %15 : $Float                             // id: %17
-}
-
-// reverse-mode derivative of g(_:)
-sil hidden @$s4test1gyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
-bb0(%0 : $Float):
-  //=========== Test callsite and closure gathering logic ===========//
-  specify_test "closure_specialize_gather_call_sites"
-  // CHECK-LABEL: Specializing closures in function: $s4test1gyS2fFTJrSpSr
-  // CHECK: PartialApply call site:   %16 = partial_apply [callee_guaranteed] %15(%6, %10, %14) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float 
-  // CHECK: Passed in closures:
-  // CHECK: 1.   %6 = partial_apply [callee_guaranteed] %5(%0) : $@convention(thin) (Float, Float) -> Float 
-  // CHECK: 2.   %10 = partial_apply [callee_guaranteed] %9(%0) : $@convention(thin) (Float, Float) -> Float 
-  // CHECK: 3.   %14 = partial_apply [callee_guaranteed] %13(%8, %4) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-
-  //=========== Test specialized function signature and body ===========//
-  specify_test "closure_specialize_specialized_function_signature_and_body"
-  // CHECK-LABEL: Generated specialized function: $s11$pullback_g7$vjpSinSf0B3CosSf0B8MultiplyS2fTf1nccc_n
-  // CHECK: sil private @$s11$pullback_g7$vjpSinSf0B3CosSf0B8MultiplyS2fTf1nccc_n : $@convention(thin) (Float, Float, Float, Float, Float) -> Float {
-  // CHECK: bb0(%0 : $Float, %1 : $Float, %2 : $Float, %3 : $Float, %4 : $Float):
-  // CHECK: %5 = function_ref @$vjpSin : $@convention(thin) (Float, Float) -> Float 
-  // CHECK: %6 = partial_apply [callee_guaranteed] %5(%1) : $@convention(thin) (Float, Float) -> Float 
-  // CHECK: %7 = function_ref @$vjpCos : $@convention(thin) (Float, Float) -> Float 
-  // CHECK: %8 = partial_apply [callee_guaranteed] %7(%2) : $@convention(thin) (Float, Float) -> Float 
-  // CHECK: %9 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK: %10 = partial_apply [callee_guaranteed] %9(%3, %4) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK: %11 = apply %10(%0) : $@callee_guaranteed (Float) -> (Float, Float) 
-  // CHECK: strong_release %10 : $@callee_guaranteed (Float) -> (Float, Float) // id: %12
-  // CHECK: %15 = apply %8(%14) : $@callee_guaranteed (Float) -> Float 
-  // CHECK: strong_release %8 : $@callee_guaranteed (Float) -> Float // id: %16
-  // CHECK: %17 = apply %6(%13) : $@callee_guaranteed (Float) -> Float 
-  // CHECK: strong_release %6 : $@callee_guaranteed (Float) -> Float // id: %18
-  // CHECK: return  
-
-  //=========== Test rewritten body ===========//
-  specify_test "closure_specialize_rewritten_caller_body"
-  // CHECK-LABEL: Rewritten caller body for: $s4test1gyS2fFTJrSpSr
-  // CHECK: sil hidden @$s4test1gyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
-  // CHECK: bb0(%0 : $Float):
-  // CHECK:  %2 = struct_extract %0 : $Float, #Float._value  
-  // CHECK:  %3 = builtin "int_sin_FPIEEE32"(%2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  // CHECK:  %4 = struct $Float (%3 : $Builtin.FPIEEE32)     
-  // CHECK:  %5 = function_ref @$vjpSin : $@convention(thin) (Float, Float) -> Float 
-  // CHECK:  %6 = partial_apply [callee_guaranteed] %5(%0) : $@convention(thin) (Float, Float) -> Float 
-  // CHECK:  %7 = builtin "int_cos_FPIEEE32"(%2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  // CHECK:  %8 = struct $Float (%7 : $Builtin.FPIEEE32)     
-  // CHECK:  %9 = function_ref @$vjpCos : $@convention(thin) (Float, Float) -> Float 
-  // CHECK:  %10 = partial_apply [callee_guaranteed] %9(%0) : $@convention(thin) (Float, Float) -> Float 
-  // CHECK:  %11 = builtin "fmul_FPIEEE32"(%3 : $Builtin.FPIEEE32, %7 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  // CHECK:  %12 = struct $Float (%11 : $Builtin.FPIEEE32)   
-  // CHECK:  %13 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK:  %14 = partial_apply [callee_guaranteed] %13(%8, %4) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK:  %16 = function_ref @$s11$pullback_g7$vjpSinSf0B3CosSf0B8MultiplyS2fTf1nccc_n : $@convention(thin) (Float, Float, Float, Float, Float) -> Float 
-  // CHECK:  %17 = partial_apply [callee_guaranteed] %16(%0, %0, %8, %4) : $@convention(thin) (Float, Float, Float, Float, Float) -> Float 
-  // CHECK:  release_value %6 : $@callee_guaranteed (Float) -> Float // id: %18
-  // CHECK:  release_value %10 : $@callee_guaranteed (Float) -> Float // id: %19
-  // CHECK:  release_value %14 : $@callee_guaranteed (Float) -> (Float, Float) // id: %20
-  // CHECK:  %21 = tuple (%12 : $Float, %17 : $@callee_guaranteed (Float) -> Float) 
-  // CHECK:  return %21
-
-  debug_value %0 : $Float, let, name "x", argno 1 // id: %1
-  %2 = struct_extract %0 : $Float, #Float._value  
-  %3 = builtin "int_sin_FPIEEE32"(%2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  %4 = struct $Float (%3 : $Builtin.FPIEEE32)     
-  // function_ref closure #1 in _vjpSin(_:)
-  %5 = function_ref @$vjpSin : $@convention(thin) (Float, Float) -> Float 
-  %6 = partial_apply [callee_guaranteed] %5(%0) : $@convention(thin) (Float, Float) -> Float 
-  %7 = builtin "int_cos_FPIEEE32"(%2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  %8 = struct $Float (%7 : $Builtin.FPIEEE32)     
-  // function_ref closure #1 in _vjpCos(_:)
-  %9 = function_ref @$vjpCos : $@convention(thin) (Float, Float) -> Float 
-  %10 = partial_apply [callee_guaranteed] %9(%0) : $@convention(thin) (Float, Float) -> Float 
-  %11 = builtin "fmul_FPIEEE32"(%3 : $Builtin.FPIEEE32, %7 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  %12 = struct $Float (%11 : $Builtin.FPIEEE32)   
-  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
-  %13 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  %14 = partial_apply [callee_guaranteed] %13(%8, %4) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // function_ref pullback of g(_:)
-  %15 = function_ref @$pullback_g : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float 
-  %16 = partial_apply [callee_guaranteed] %15(%6, %10, %14) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float 
-  %17 = tuple (%12 : $Float, %16 : $@callee_guaranteed (Float) -> Float) 
-  return %17 : $(Float, @callee_guaranteed (Float) -> Float) // id: %18
-}
-
-///////////////////////////////
-/// Parameter subset thunks ///
-///////////////////////////////
-struct X : Differentiable {
-  @_hasStorage var a: Float { get set }
-  @_hasStorage var b: Double { get set }
-  struct TangentVector : AdditiveArithmetic, Differentiable {
-    @_hasStorage var a: Float { get set }
-    @_hasStorage var b: Double { get set }
-    static func + (lhs: X.TangentVector, rhs: X.TangentVector) -> X.TangentVector
-    static func - (lhs: X.TangentVector, rhs: X.TangentVector) -> X.TangentVector
-    @_implements(Equatable, ==(_:_:)) static func __derived_struct_equals(_ a: X.TangentVector, _ b: X.TangentVector) -> Bool
-    typealias TangentVector = X.TangentVector
-    init(a: Float, b: Double)
-    static var zero: X.TangentVector { get }
-  }
-  init(a: Float, b: Double)
-  mutating func move(by offset: X.TangentVector)
-}
-
-sil [transparent] [thunk] @subset_parameter_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector
-
-sil @pullback_f : $@convention(thin) (Float, Double) -> X.TangentVector
-
-sil shared @pullback_g : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) -> X.TangentVector {
-bb0(%0 : $Float, %1 : $@callee_guaranteed (Float) -> X.TangentVector):
-  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> X.TangentVector
-  strong_release %1 : $@callee_guaranteed (Float) -> X.TangentVector
-  return %2 : $X.TangentVector
-}
-
-sil hidden @$s5test21g1xSfAA1XV_tFTJrSpSr : $@convention(thin) (X) -> (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) {
-bb0(%0 : $X):
-  //=========== Test callsite and closure gathering logic ===========//
-  specify_test "closure_specialize_gather_call_sites"
-  // CHECK-LABEL: Specializing closures in function: $s5test21g1xSfAA1XV_tFTJrSpSr
-  // CHECK: PartialApply call site:   %7 = partial_apply [callee_guaranteed] %6(%5) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) -> X.TangentVector 
-  // CHECK: Passed in closures:
-  // CHECK: 1.   %3 = thin_to_thick_function %2 : $@convention(thin) (Float, Double) -> X.TangentVector to $@callee_guaranteed (Float, Double) -> X.TangentVector 
-
-  //=========== Test specialized function signature and body ===========//
-  specify_test "closure_specialize_specialized_function_signature_and_body"
-  // CHECK-LABEL: Generated specialized function: $s10pullback_g0A2_fTf1nc_n
-  // CHECK: sil shared @$s10pullback_g0A2_fTf1nc_n : $@convention(thin) (Float) -> X.TangentVector {
-  // CHECK: bb0(%0 : $Float):
-  // CHECK:   %1 = function_ref @pullback_f : $@convention(thin) (Float, Double) -> X.TangentVector 
-  // CHECK:   %2 = thin_to_thick_function %1 : $@convention(thin) (Float, Double) -> X.TangentVector to $@callee_guaranteed (Float, Double) -> X.TangentVector 
-  // CHECK:   %3 = function_ref @subset_parameter_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector 
-  // CHECK:   %4 = partial_apply [callee_guaranteed] %3(%2) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector 
-  // CHECK:   %5 = apply %4(%0) : $@callee_guaranteed (Float) -> X.TangentVector 
-  // CHECK:   strong_release %4 : $@callee_guaranteed (Float) -> X.TangentVector // id: %6
-  // CHECK:   return %5 : $X.TangentVector                    // id: %7
-  
-  //=========== Test rewritten body ===========//
-  specify_test "closure_specialize_rewritten_caller_body"
-  // CHECK-LABEL: Rewritten caller body for: $s5test21g1xSfAA1XV_tFTJrSpSr
-  // CHECK: sil hidden @$s5test21g1xSfAA1XV_tFTJrSpSr : $@convention(thin) (X) -> (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) {
-  // CHECK: bb0(%0 : $X):
-  // CHECK:  %1 = struct_extract %0 : $X, #X.a               
-  // CHECK:  %2 = function_ref @pullback_f : $@convention(thin) (Float, Double) -> X.TangentVector 
-  // CHECK:  %3 = thin_to_thick_function %2 : $@convention(thin) (Float, Double) -> X.TangentVector to $@callee_guaranteed (Float, Double) -> X.TangentVector 
-  // CHECK:  %4 = function_ref @subset_parameter_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector 
-  // CHECK:  %5 = partial_apply [callee_guaranteed] %4(%3) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector
-  // CHECK:  %7 = function_ref @$s10pullback_g0A2_fTf1nc_n : $@convention(thin) (Float) -> X.TangentVector 
-  // CHECK:  %8 = partial_apply [callee_guaranteed] %7() : $@convention(thin) (Float) -> X.TangentVector 
-  // CHECK:  release_value %3 : $@callee_guaranteed (Float, Double) -> X.TangentVector // id: %9
-  // CHECK:  %10 = tuple (%1 : $Float, %8 : $@callee_guaranteed (Float) -> X.TangentVector) 
-  // CHECK:  return %10
-  
-  %1 = struct_extract %0 : $X, #X.a               
-  // function_ref pullback_f
-  %2 = function_ref @pullback_f : $@convention(thin) (Float, Double) -> X.TangentVector 
-  %3 = thin_to_thick_function %2 : $@convention(thin) (Float, Double) -> X.TangentVector to $@callee_guaranteed (Float, Double) -> X.TangentVector 
-  // function_ref subset_parameter_thunk
-  %4 = function_ref @subset_parameter_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector 
-  %5 = partial_apply [callee_guaranteed] %4(%3) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector 
-  // function_ref pullback_g
-  %6 = function_ref @pullback_g : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) -> X.TangentVector 
-  %7 = partial_apply [callee_guaranteed] %6(%5) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) -> X.TangentVector 
-  %8 = tuple (%1 : $Float, %7 : $@callee_guaranteed (Float) -> X.TangentVector) 
-  return %8 : $(Float, @callee_guaranteed (Float) -> X.TangentVector) // id: %9
-}
-
-///////////////////////////////////////////////////////////////////////
-///////// Specialized generic closures - PartialApply Closure /////////
-///////////////////////////////////////////////////////////////////////
-
-// closure #1 in static Float._vjpMultiply(lhs:rhs:)
-sil @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
-
-// thunk for @escaping @callee_guaranteed (@unowned Float) -> (@unowned Float, @unowned Float)
-sil [transparent] [reabstraction_thunk] @$sS3fIegydd_S3fIegnrr_TR : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float)
-
-// function_ref specialized pullback of f<A>(a:)
-sil [transparent] [thunk] @pullback_f_specialized : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float
-
-// thunk for @escaping @callee_guaranteed (@in_guaranteed Float) -> (@out Float)
-sil [transparent] [reabstraction_thunk] @$sS2fIegnr_S2fIegyd_TR : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
-
-sil private [signature_optimized_thunk] [always_inline] @pullback_h : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float {
-bb0(%0 : $Float, %1 : $@callee_guaranteed (Float) -> Float):
-  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> Float
-  strong_release %1 : $@callee_guaranteed (Float) -> Float
-  return %2 : $Float
-}
-
-// reverse-mode derivative of h(x:)
-sil hidden @$s5test21h1xS2f_tFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
-bb0(%0 : $Float):
-  //=========== Test callsite and closure gathering logic ===========//
-  specify_test "closure_specialize_gather_call_sites"
-  // CHECK-LABEL: Specializing closures in function: $s5test21h1xS2f_tFTJrSpSr
-  // CHECK: PartialApply call site:     %14 = partial_apply [callee_guaranteed] %13(%11) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float 
-  // CHECK: Passed in closures:
-  // CHECK: 1.   %4 = partial_apply [callee_guaranteed] %3(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-
-  //=========== Test specialized function signature and body ===========//
-  specify_test "closure_specialize_specialized_function_signature_and_body"
-  // CHECK-LABEL: Generated specialized function: $s10pullback_h073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbackti1_j5FZSf_J6SfcfU_S2fTf1nc_n
-  // CHECK: sil private [signature_optimized_thunk] [always_inline] @$s10pullback_h073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbackti1_j5FZSf_J6SfcfU_S2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float {
-  // CHECK: bb0(%0 : $Float, %1 : $Float, %2 : $Float):
-  // CHECK:   %3 = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK:   %4 = partial_apply [callee_guaranteed] %3(%1, %2) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK:   %5 = function_ref @$sS3fIegydd_S3fIegnrr_TR : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float) 
-  // CHECK:   %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float) 
-  // CHECK:   %7 = convert_function %6 : $@callee_guaranteed (@in_guaranteed Float) -> (@out Float, @out Float) to $@callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float> 
-  // CHECK:   %8 = function_ref @pullback_f_specialized : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float 
-  // CHECK:   %9 = partial_apply [callee_guaranteed] %8(%7) : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float 
-  // CHECK:   %10 = function_ref @$sS2fIegnr_S2fIegyd_TR : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  // CHECK:   %11 = partial_apply [callee_guaranteed] %10(%9) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  // CHECK:   %12 = apply %11(%0) : $@callee_guaranteed (Float) -> Float 
-  // CHECK:   strong_release %11 : $@callee_guaranteed (Float) -> Float // id: %13
-  // CHECK:   return %12 : $Float
-
-  //=========== Test rewritten body ===========//
-  specify_test "closure_specialize_rewritten_caller_body"
-  // CHECK-LABEL: Rewritten caller body for: $s5test21h1xS2f_tFTJrSpSr
-  // CHECK:sil hidden @$s5test21h1xS2f_tFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
-  // CHECK:bb0(%0 : $Float):
-  // CHECK:  %1 = struct_extract %0 : $Float, #Float._value  
-  // CHECK:  %2 = builtin "fmul_FPIEEE32"(%1 : $Builtin.FPIEEE32, %1 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  // CHECK:  %3 = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK:  %4 = partial_apply [callee_guaranteed] %3(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  // CHECK:  %5 = function_ref @$sS3fIegydd_S3fIegnrr_TR : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float) 
-  // CHECK:  %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float) 
-  // CHECK:  %7 = convert_function %6 : $@callee_guaranteed (@in_guaranteed Float) -> (@out Float, @out Float) to $@callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float> 
-  // CHECK:  %8 = function_ref @pullback_f_specialized : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float 
-  // CHECK:  %9 = partial_apply [callee_guaranteed] %8(%7) : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float 
-  // CHECK:  %10 = function_ref @$sS2fIegnr_S2fIegyd_TR : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  // CHECK:  %11 = partial_apply [callee_guaranteed] %10(%9) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
-  // CHECK:  %12 = struct $Float (%2 : $Builtin.FPIEEE32)    
-  // CHECK:  %14 = function_ref @$s10pullback_h073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbackti1_j5FZSf_J6SfcfU_S2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float 
-  // CHECK:  %15 = partial_apply [callee_guaranteed] %14(%0, %0) : $@convention(thin) (Float, Float, Float) -> Float 
-  // CHECK:  release_value %4 : $@callee_guaranteed (Float) -> (Float, Float) // id: %16
-  // CHECK:  %17 = tuple (%12 : $Float, %15 : $@callee_guaranteed (Float) -> Float) 
-  // CHECK:  return %17
-
-  %1 = struct_extract %0 : $Float, #Float._value  
-  %2 = builtin "fmul_FPIEEE32"(%1 : $Builtin.FPIEEE32, %1 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32 
-  
-  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
-  %3 = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  %4 = partial_apply [callee_guaranteed] %3(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float) 
-  
-  // function_ref thunk for @escaping @callee_guaranteed (@unowned Float) -> (@unowned Float, @unowned Float)
-  %5 = function_ref @$sS3fIegydd_S3fIegnrr_TR : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float) 
-  %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float) 
-  %7 = convert_function %6 : $@callee_guaranteed (@in_guaranteed Float) -> (@out Float, @out Float) to $@callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float> 
-  
-  // function_ref pullback_f_specialized
-  %8 = function_ref @pullback_f_specialized : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float 
-  %9 = partial_apply [callee_guaranteed] %8(%7) : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float 
-  
-  // function_ref thunk for @escaping @callee_guaranteed (@in_guaranteed Float) -> (@out Float)
-  %10 = function_ref @$sS2fIegnr_S2fIegyd_TR : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  %11 = partial_apply [callee_guaranteed] %10(%9) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  %12 = struct $Float (%2 : $Builtin.FPIEEE32)    
-  
-  // function_ref pullback_h
-  %13 = function_ref @pullback_h : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float 
-  %14 = partial_apply [callee_guaranteed] %13(%11) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float 
-  %15 = tuple (%12 : $Float, %14 : $@callee_guaranteed (Float) -> Float) 
-  return %15 : $(Float, @callee_guaranteed (Float) -> Float) // id: %16
-}
-
-//////////////////////////////////////////////////////////////////////////////
-///////// Specialized generic closures - ThinToThickFunction closure /////////
-//////////////////////////////////////////////////////////////////////////////
-
-sil [transparent] [thunk] @pullback_y_specialized : $@convention(thin) (@in_guaranteed Float) -> @out Float
-
-sil [transparent] [reabstraction_thunk] @reabstraction_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
-
-sil private [signature_optimized_thunk] [always_inline] @pullback_z : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float {
-bb0(%0 : $Float, %1 : $@callee_guaranteed (Float) -> Float):
-  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> Float
-  strong_release %1 : $@callee_guaranteed (Float) -> Float
-  return %2 : $Float
-}
-
-sil hidden @$s5test21z1xS2f_tFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
-bb0(%0 : $Float):
-  //=========== Test callsite and closure gathering logic ===========//
-  specify_test "closure_specialize_gather_call_sites"
-  // CHECK-LABEL: Specializing closures in function: $s5test21z1xS2f_tFTJrSpSr
-  // CHECK: PartialApply call site:   %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float 
-  // CHECK: Passed in closures:
-  // CHECK: 1.   %2 = thin_to_thick_function %1 : $@convention(thin) (@in_guaranteed Float) -> @out Float to $@callee_guaranteed (@in_guaranteed Float) -> @out Float 
-
-  //=========== Test specialized function signature and body ===========//
-  specify_test "closure_specialize_specialized_function_signature_and_body"
-  // CHECK-LABEL: Generated specialized function: $s10pullback_z0A14_y_specializedTf1nc_n
-  // CHECK: sil private [signature_optimized_thunk] [always_inline] @$s10pullback_z0A14_y_specializedTf1nc_n : $@convention(thin) (Float) -> Float {
-  // CHECK: bb0(%0 : $Float):
-  // CHECK:   %1 = function_ref @pullback_y_specialized : $@convention(thin) (@in_guaranteed Float) -> @out Float 
-  // CHECK:   %2 = thin_to_thick_function %1 : $@convention(thin) (@in_guaranteed Float) -> @out Float to $@callee_guaranteed (@in_guaranteed Float) -> @out Float 
-  // CHECK:   %3 = function_ref @reabstraction_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  // CHECK:   %4 = partial_apply [callee_guaranteed] %3(%2) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  // CHECK:   %5 = apply %4(%0) : $@callee_guaranteed (Float) -> Float 
-  // CHECK:   strong_release %4 : $@callee_guaranteed (Float) -> Float // id: %6
-  // CHECK:   return %5 : $Float
-
-  //=========== Test rewritten body ===========//
-  specify_test "closure_specialize_rewritten_caller_body"
-  // CHECK-LABEL: Rewritten caller body for: $s5test21z1xS2f_tFTJrSpSr
-  // CHECK: sil hidden @$s5test21z1xS2f_tFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
-  // CHECK: bb0(%0 : $Float):
-  // CHECK:   %1 = function_ref @pullback_y_specialized : $@convention(thin) (@in_guaranteed Float) -> @out Float 
-  // CHECK:   %2 = thin_to_thick_function %1 : $@convention(thin) (@in_guaranteed Float) -> @out Float to $@callee_guaranteed (@in_guaranteed Float) -> @out Float 
-  // CHECK:   %3 = function_ref @reabstraction_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  // CHECK:   %4 = partial_apply [callee_guaranteed] %3(%2) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
-  // CHECK:   %6 = function_ref @$s10pullback_z0A14_y_specializedTf1nc_n : $@convention(thin) (Float) -> Float 
-  // CHECK:   %7 = partial_apply [callee_guaranteed] %6() : $@convention(thin) (Float) -> Float 
-  // CHECK:   release_value %2 : $@callee_guaranteed (@in_guaranteed Float) -> @out Float // id: %8
-  // CHECK:   %9 = tuple (%0 : $Float, %7 : $@callee_guaranteed (Float) -> Float) 
-  // CHECK:   return %9
-
-  // function_ref pullback_y_specialized
-  %1 = function_ref @pullback_y_specialized : $@convention(thin) (@in_guaranteed Float) -> @out Float 
-  %2 = thin_to_thick_function %1 : $@convention(thin) (@in_guaranteed Float) -> @out Float to $@callee_guaranteed (@in_guaranteed Float) -> @out Float 
-  // function_ref reabstraction_thunk
-  %3 = function_ref @reabstraction_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  %4 = partial_apply [callee_guaranteed] %3(%2) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float 
-  // function_ref pullback_z
-  %5 = function_ref @pullback_z : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float 
-  %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float 
-  %7 = tuple (%0 : $Float, %6 : $@callee_guaranteed (Float) -> Float) 
-  return %7 : $(Float, @callee_guaranteed (Float) -> Float) // id: %8
-}
diff --git a/test/AutoDiff/SILOptimizer/closure_specialization/multi_bb_bte.sil b/test/AutoDiff/SILOptimizer/closure_specialization/multi_bb_bte.sil
new file mode 100644
index 0000000000000..7d705d7eaf4b8
--- /dev/null
+++ b/test/AutoDiff/SILOptimizer/closure_specialization/multi_bb_bte.sil
@@ -0,0 +1,593 @@
+/// Multi basic block VJP, pullback accepting branch tracing enum argument.
+
+// RUN: %target-sil-opt -sil-print-types -autodiff-closure-specialization -sil-combine %s -o - | %FileCheck %s --check-prefixes=COMBINE,CHECK
+
+// REQUIRES: swift_in_compiler
+
+sil_stage canonical
+
+import Builtin
+import Swift
+import SwiftShims
+
+import _Differentiation
+
+///////////////////
+/// Test case 1 ///
+///////////////////
+
+/// This SIL corresponds to the following Swift:
+///
+/// @differentiable(reverse)
+/// func mul42(_ a: Float?) -> Float {
+///   let b = 42 * a!
+///   return b
+/// }
+
+enum _AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0 {
+  case bb0(())
+}
+
+sil @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+sil [transparent] [thunk] @$sS3fIegydd_TJSpSSUpSrUSUP : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+
+// pullback of mul42(_:)
+sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @$s4test5mul42yS2fSgFTJpSpSr : $@convention(thin) (Float, _AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0, @owned @callee_guaranteed (Float) -> Float) -> Optional<Float>.TangentVector {
+bb0(%0 : $Float, %1 : $_AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0, %2 : @owned $@callee_guaranteed (Float) -> Float):
+  %4 = apply %2(%0) : $@callee_guaranteed (Float) -> Float
+  destroy_value %2
+  %6 = enum $Optional<Float>, #Optional.some!enumelt, %4
+  %7 = struct $Optional<Float>.TangentVector (%6)
+  return %7
+} // end sil function '$s4test5mul42yS2fSgFTJpSpSr'
+
+// reverse-mode derivative of mul42(_:)
+sil hidden [ossa] @$s4test5mul42yS2fSgFTJrSpSr : $@convention(thin) (Optional<Float>) -> (Float, @owned @callee_guaranteed (Float) -> Optional<Float>.TangentVector) {
+bb0(%0 : $Optional<Float>):
+  // CHECK:         sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @$s4test5mul42yS2fSgFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_S2fTf1nnc_n : $@convention(thin) (Float, _AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0, Float, Float) -> Optional<Float>.TangentVector {
+  // CHECK:         bb0(%0 : $Float, %1 : $_AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0, %2 : $Float, %3 : $Float):
+  // CHECK:           %[[#A6:]] = function_ref @$sS3fIegydd_TJSpSSUpSrUSUP : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  // CHECK:           %[[#A4:]] = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // CHECK:           %[[#A5:]] = partial_apply [callee_guaranteed] %[[#A4]](%2, %3) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // COMBINE-NOT:     = partial_apply
+  // COMBINE:         %[[#A8:]] = apply %[[#A6]](%0, %[[#A5]]) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  // CHECK:           %[[#A10:]] = enum $Optional<Float>, #Optional.some!enumelt, %[[#A8]] : $Float
+  // CHECK:           %[[#A11:]] = struct $Optional<Float>.TangentVector (%[[#A10]] : $Optional<Float>)
+  // CHECK:           return %[[#A11]] : $Optional<Float>.TangentVector
+
+  // CHECK:         sil hidden [ossa] @$s4test5mul42yS2fSgFTJrSpSr : $@convention(thin) (Optional<Float>) -> (Float, @owned @callee_guaranteed (Float) -> Optional<Float>.TangentVector) {
+  // CHECK:         bb1(%2 : $Float):
+  // CHECK:         %[[#B4:]] = struct $Float (%[[#]] : $Builtin.FPIEEE32)
+  // COMBINE-NOT:   = partial_apply
+  // COMBINE-NOT:   = function_ref
+  // CHECK:         %[[#B15:]] = function_ref @$s4test5mul42yS2fSgFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_S2fTf1nnc_n : $@convention(thin) (Float, _AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0, Float, Float) -> Optional<Float>.TangentVector
+  // CHECK:         %[[#B16:]] = partial_apply [callee_guaranteed] %[[#B15]](%[[#]], %2, %[[#B4]]) : $@convention(thin) (Float, _AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0, Float, Float) -> Optional<Float>.TangentVector
+  // CHECK:         %[[#B18:]] = tuple (%[[#]] : $Float, %[[#B16]] : $@callee_guaranteed (Float) -> Optional<Float>.TangentVector)
+  // CHECK:         return %[[#B18]]
+
+  switch_enum %0, case #Optional.some!enumelt: bb1, case #Optional.none!enumelt: bb2
+
+bb1(%3 : $Float):
+  %4 = float_literal $Builtin.FPIEEE32, 0x42280000 // 42
+  %5 = struct $Float (%4)
+  %6 = tuple ()
+  %7 = enum $_AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0, #_AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0.bb0!enumelt, %6
+  %8 = struct_extract %3, #Float._value
+  %9 = builtin "fmul_FPIEEE32"(%4, %8) : $Builtin.FPIEEE32
+  %10 = struct $Float (%9)
+  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
+  %11 = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %12 = partial_apply [callee_guaranteed] %11(%3, %5) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // function_ref autodiff subset parameters thunk for pullback from @escaping @callee_guaranteed (@unowned Float) -> (@unowned Float, @unowned Float)
+  %13 = function_ref @$sS3fIegydd_TJSpSSUpSrUSUP : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %14 = partial_apply [callee_guaranteed] %13(%12) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  // function_ref pullback of mul42(_:)
+  %16 = function_ref @$s4test5mul42yS2fSgFTJpSpSr : $@convention(thin) (Float, _AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0, @owned @callee_guaranteed (Float) -> Float) -> Optional<Float>.TangentVector
+  %17 = partial_apply [callee_guaranteed] %16(%7, %14) : $@convention(thin) (Float, _AD__$s4test5mul42yS2fSgF_bb2__Pred__src_0_wrt_0, @owned @callee_guaranteed (Float) -> Float) -> Optional<Float>.TangentVector
+  %18 = tuple (%10, %17)
+  return %18
+
+bb2:
+  unreachable
+} // end sil function '$s4test5mul42yS2fSgFTJrSpSr'
+
+///////////////////
+/// Test case 2 ///
+///////////////////
+
+/// This SIL corresponds to the following Swift:
+///
+/// struct Class: Differentiable {
+///   var stored: Float
+///   var optional: Float?
+///
+///   init(stored: Float, optional: Float?) {
+///     self.stored = stored
+///     self.optional = optional
+///   }
+///
+///   @differentiable(reverse)
+///   func method() -> Float {
+///     let c: Class
+///     do {
+///       let tmp = Class(stored: 1 * stored, optional: optional)
+///       let tuple = (tmp, tmp)
+///       c = tuple.0
+///     }
+///     var ret : Float = 0
+///     if let x = c.optional {
+///       ret = x * c.stored
+///     } else {
+///       ret = 1 * c.stored
+///     }
+///     return 1 * ret * ret
+///   }
+/// }
+
+struct Class : Differentiable {
+  @_hasStorage var stored: Float { get set }
+  @_hasStorage @_hasInitialValue var optional: Float? { get set }
+  init(stored: Float, optional: Float?)
+  @differentiable(reverse, wrt: self)
+  func method() -> Float
+  struct TangentVector : AdditiveArithmetic, Differentiable {
+    @_hasStorage var stored: Float { get set }
+    @_hasStorage var optional: Optional<Float>.TangentVector { get set }
+    static func + (lhs: Class.TangentVector, rhs: Class.TangentVector) -> Class.TangentVector
+    static func - (lhs: Class.TangentVector, rhs: Class.TangentVector) -> Class.TangentVector
+    typealias TangentVector = Class.TangentVector
+    @_implements(Equatable, ==(_:_:)) static func __derived_struct_equals(_ a: Class.TangentVector, _ b: Class.TangentVector) -> Bool
+    init(stored: Float, optional: Optional<Float>.TangentVector)
+    static var zero: Class.TangentVector { get }
+  }
+  mutating func move(by offset: Class.TangentVector)
+}
+
+enum _AD__$s4test5ClassV6methodSfyF_bb0__Pred__src_0_wrt_0 {
+}
+
+enum _AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0 {
+  case bb0(((Float) -> Float, (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)))
+}
+
+enum _AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0 {
+  case bb0(((Float) -> Float, (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)))
+}
+
+enum _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0 {
+  case bb2((predecessor: _AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0, (Float) -> Float))
+  case bb1((predecessor: _AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0, (Float) -> (Float, Float)))
+}
+
+enum _AD__$s4test13methodWrapperySfAA5ClassVF_bb0__Pred__src_0_wrt_0 {
+}
+
+enum _AD__$s4test5ClassV6stored8optionalACSf_SfSgtcfC_bb0__Pred__src_0_wrt_0_1 {
+}
+
+sil @$s4test5ClassV6stored8optionalACSf_SfSgtcfCTJpSSUpSr : $@convention(thin) (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)
+
+// pullback of Class.method()
+sil private [ossa] @$s4test5ClassV6methodSfyFTJpSpSr : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Class.TangentVector {
+bb0(%0 : $Float, %1 : @owned $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, %2 : @owned $@callee_guaranteed (Float) -> Float, %3 : @owned $@callee_guaranteed (Float) -> (Float, Float)):
+  %4 = float_literal $Builtin.FPIEEE32, 0x0 // 0
+  %8 = apply %3(%0) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %3
+  %10 = tuple_extract %8, 0
+  %11 = tuple_extract %8, 1
+  %12 = struct_extract %11, #Float._value
+  %13 = builtin "fadd_FPIEEE32"(%4, %12) : $Builtin.FPIEEE32
+  %15 = apply %2(%10) : $@callee_guaranteed (Float) -> Float
+  destroy_value %2
+  %17 = struct_extract %15, #Float._value
+  %18 = builtin "fadd_FPIEEE32"(%13, %17) : $Builtin.FPIEEE32
+  switch_enum %1, case #_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0.bb2!enumelt: bb1, case #_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0.bb1!enumelt: bb2
+
+bb1(%37 : @owned $(predecessor: _AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> Float)):
+  (%38, %39) = destructure_tuple %37
+  %40 = builtin "fadd_FPIEEE32"(%18, %4) : $Builtin.FPIEEE32
+  %41 = struct $Float (%40)
+  %42 = apply %39(%41) : $@callee_guaranteed (Float) -> Float
+  destroy_value %39
+  %44 = struct_extract %42, #Float._value
+  %45 = builtin "fadd_FPIEEE32"(%44, %4) : $Builtin.FPIEEE32
+  %46 = builtin "fadd_FPIEEE32"(%4, %45) : $Builtin.FPIEEE32
+  %50 = unchecked_enum_data %38, #_AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0.bb0!enumelt
+  (%51, %52) = destructure_tuple %50
+  br bb3(%4, %46, %51, %52)
+
+bb2(%54 : @owned $(predecessor: _AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> (Float, Float))):
+  (%55, %56) = destructure_tuple %54
+  %57 = builtin "fadd_FPIEEE32"(%18, %4) : $Builtin.FPIEEE32
+  %58 = struct $Float (%57)
+  %59 = apply %56(%58) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %56
+  %61 = tuple_extract %59, 0
+  %62 = tuple_extract %59, 1
+  %63 = struct_extract %61, #Float._value
+  %64 = builtin "fadd_FPIEEE32"(%63, %4) : $Builtin.FPIEEE32
+  %65 = struct_extract %62, #Float._value
+  %66 = builtin "fadd_FPIEEE32"(%65, %4) : $Builtin.FPIEEE32
+  %67 = builtin "fadd_FPIEEE32"(%4, %66) : $Builtin.FPIEEE32
+  %69 = builtin "fadd_FPIEEE32"(%64, %4) : $Builtin.FPIEEE32
+  %70 = builtin "fadd_FPIEEE32"(%69, %4) : $Builtin.FPIEEE32
+  %73 = unchecked_enum_data %55, #_AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0.bb0!enumelt
+  (%74, %75) = destructure_tuple %73
+  br bb3(%70, %67, %74, %75)
+
+bb3(%77 : $Builtin.FPIEEE32, %78 : $Builtin.FPIEEE32, %79 : @owned $@callee_guaranteed (Float) -> Float, %80 : @owned $@callee_guaranteed (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)):
+  %81 = builtin "fadd_FPIEEE32"(%4, %77) : $Builtin.FPIEEE32
+  %85 = builtin "fadd_FPIEEE32"(%78, %4) : $Builtin.FPIEEE32
+  %87 = builtin "fadd_FPIEEE32"(%81, %4) : $Builtin.FPIEEE32
+  %89 = builtin "fadd_FPIEEE32"(%85, %4) : $Builtin.FPIEEE32
+  %91 = builtin "fadd_FPIEEE32"(%87, %4) : $Builtin.FPIEEE32
+  %93 = builtin "fadd_FPIEEE32"(%89, %4) : $Builtin.FPIEEE32
+  %95 = builtin "fadd_FPIEEE32"(%91, %4) : $Builtin.FPIEEE32
+  %97 = builtin "fadd_FPIEEE32"(%93, %4) : $Builtin.FPIEEE32
+  %99 = builtin "fadd_FPIEEE32"(%95, %4) : $Builtin.FPIEEE32
+  %100 = builtin "fadd_FPIEEE32"(%4, %97) : $Builtin.FPIEEE32
+  %102 = builtin "fadd_FPIEEE32"(%4, %99) : $Builtin.FPIEEE32
+  %104 = builtin "fadd_FPIEEE32"(%100, %4) : $Builtin.FPIEEE32
+  %105 = struct $Float (%104)
+  %106 = builtin "fadd_FPIEEE32"(%102, %4) : $Builtin.FPIEEE32
+  %107 = struct $Float (%106)
+  %108 = enum $Optional<Float>, #Optional.some!enumelt, %107
+  %109 = struct $Optional<Float>.TangentVector (%108)
+  %110 = struct $Class.TangentVector (%105, %109)
+  %111 = apply %80(%110) : $@callee_guaranteed (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)
+  destroy_value %80
+  %113 = tuple_extract %111, 1
+  %114 = struct_extract %113, #Optional.TangentVector.value
+  switch_enum %114, case #Optional.none!enumelt: bb4, case #Optional.some!enumelt: bb5
+
+bb4:
+  br bb6(%4)
+
+bb5(%117 : $Float):
+  %118 = unchecked_enum_data %114, #Optional.some!enumelt
+  %119 = struct_extract %118, #Float._value
+  %120 = builtin "fadd_FPIEEE32"(%119, %4) : $Builtin.FPIEEE32
+  br bb6(%120)
+
+bb6(%122 : $Builtin.FPIEEE32):
+  %123 = tuple_extract %111, 0
+  %124 = struct_extract %123, #Float._value
+  %125 = builtin "fadd_FPIEEE32"(%124, %4) : $Builtin.FPIEEE32
+  %126 = struct $Float (%125)
+  %127 = apply %79(%126) : $@callee_guaranteed (Float) -> Float
+  destroy_value %79
+  %129 = struct_extract %127, #Float._value
+  %130 = builtin "fadd_FPIEEE32"(%129, %4) : $Builtin.FPIEEE32
+  %131 = builtin "fadd_FPIEEE32"(%4, %130) : $Builtin.FPIEEE32
+  %132 = builtin "fadd_FPIEEE32"(%4, %122) : $Builtin.FPIEEE32
+  %133 = struct $Float (%132)
+  %134 = enum $Optional<Float>, #Optional.some!enumelt, %133
+  %135 = struct $Float (%131)
+  %136 = struct $Optional<Float>.TangentVector (%134)
+  %137 = struct $Class.TangentVector (%135, %136)
+  return %137
+} // end sil function '$s4test5ClassV6methodSfyFTJpSpSr'
+
+// reverse-mode derivative of Class.method()
+sil hidden [ossa] @$s4test5ClassV6methodSfyFTJrSpSr : $@convention(method) (Class) -> (Float, @owned @callee_guaranteed (Float) -> Class.TangentVector) {
+bb0(%0 : $Class):
+  // CHECK:         sil private [ossa] @$s4test5ClassV6methodSfyFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktk1_l5FZSf_L6SfcfU_S2fAES2fTf1nncc_n : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, Float, Float, Float, Float) -> Class.TangentVector {
+  // CHECK:         bb0(%0 : $Float, %1 : @owned $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, %2 : $Float, %3 : $Float, %4 : $Float, %5 : $Float):
+  // CHECK:           %[[#D8:]] = function_ref @$sS3fIegydd_TJSpSSUpSrUSUP : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  // CHECK:           %[[#D6:]] = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // CHECK:           %[[#D7:]] = partial_apply [callee_guaranteed] %[[#D6]](%2, %3) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // COMBINE-NOT:     = partial_apply
+  // COMBINE:         %[[#D13:]] = apply %[[#D6]](%0, %4, %5) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // CHECK:           %[[#D15:]] = tuple_extract %[[#D13]] : $(Float, Float), 0
+  // COMBINE:         %[[#]] = apply %[[#D8]](%[[#D15]], %[[#D7]]) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+
+  // CHECK:         sil hidden [ossa] @$s4test5ClassV6methodSfyFTJrSpSr : $@convention(method) (Class) -> (Float, @owned @callee_guaranteed (Float) -> Class.TangentVector) {
+  // CHECK:         bb0(%0 : $Class):
+  // CHECK:           %[[#E2:]] = struct $Float
+  // CHECK:           %[[#E7:]] = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // CHECK:           %[[#E9:]] = function_ref @$sS3fIegydd_TJSpSSUpSrUSUP : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  // CHECK:         bb1(%[[#]] : $Float):
+  // CHECK:         bb2:
+  // CHECK:         bb3(%[[#E33:]] : @owned $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, %[[#E34:]] : $Float):
+  // CHECK:           %[[#E37:]] = struct $Float
+
+
+  // COMBINE-NOT:     = partial_apply
+  // COMBINE-NOT:     = function_ref @$s4test5ClassV6methodSfyFTJpSpSr
+
+  // CHECK:           %[[#E44:]] = function_ref @$s4test5ClassV6methodSfyFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktk1_l5FZSf_L6SfcfU_S2fAES2fTf1nncc_n : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, Float, Float, Float, Float) -> Class.TangentVector
+  // CHECK:           %[[#E45:]] = partial_apply [callee_guaranteed] %[[#E44]](%[[#E33]], %[[#E34]], %[[#E2]], %[[#E34]], %[[#E37]]) : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, Float, Float, Float, Float) -> Class.TangentVector
+  // CHECK:           %[[#E48:]] = tuple (%[[#]] : $Float, %[[#E45]] : $@callee_guaranteed (Float) -> Class.TangentVector)
+  // CHECK:           return %[[#E48]]
+
+  %2 = float_literal $Builtin.FPIEEE32, 0x3F800000 // 1
+  %3 = struct $Float (%2)
+  %4 = struct_extract %0, #Class.stored
+  %5 = struct_extract %4, #Float._value
+  %6 = builtin "fmul_FPIEEE32"(%2, %5) : $Builtin.FPIEEE32
+  %7 = struct $Float (%6)
+  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
+  %8 = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %9 = partial_apply [callee_guaranteed] %8(%4, %3) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // function_ref autodiff subset parameters thunk for pullback from @escaping @callee_guaranteed (@unowned Float) -> (@unowned Float, @unowned Float)
+  %10 = function_ref @$sS3fIegydd_TJSpSSUpSrUSUP : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %11 = partial_apply [callee_guaranteed] %10(%9) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %12 = struct_extract %0, #Class.optional
+  // function_ref pullback of Class.init(stored:optional:)
+  %25 = function_ref @$s4test5ClassV6stored8optionalACSf_SfSgtcfCTJpSSUpSr : $@convention(thin) (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)
+  %26 = thin_to_thick_function %25 to $@callee_guaranteed (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)
+  %27 = tuple (%11, %26)
+  switch_enum %12, case #Optional.some!enumelt: bb1, case #Optional.none!enumelt: bb2
+
+bb1(%29 : $Float):
+  %30 = enum $_AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0, #_AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0.bb0!enumelt, %27
+  %32 = struct_extract %29, #Float._value
+  %33 = builtin "fmul_FPIEEE32"(%32, %6) : $Builtin.FPIEEE32
+  %34 = struct $Float (%33)
+  %35 = partial_apply [callee_guaranteed] %8(%7, %29) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %36 = tuple $(predecessor: _AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> (Float, Float)) (%30, %35)
+  %37 = enum $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, #_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0.bb1!enumelt, %36
+  br bb3(%37, %34)
+
+bb2:
+  %39 = enum $_AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0, #_AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0.bb0!enumelt, %27
+  %40 = builtin "fmul_FPIEEE32"(%2, %6) : $Builtin.FPIEEE32
+  %41 = struct $Float (%40)
+  %42 = partial_apply [callee_guaranteed] %8(%7, %3) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %43 = partial_apply [callee_guaranteed] %10(%42) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %44 = tuple $(predecessor: _AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> Float) (%39, %43)
+  %45 = enum $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, #_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0.bb2!enumelt, %44
+  br bb3(%45, %41)
+
+bb3(%47 : @owned $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, %48 : $Float):
+  %49 = struct_extract %48, #Float._value
+  %50 = builtin "fmul_FPIEEE32"(%2, %49) : $Builtin.FPIEEE32
+  %51 = struct $Float (%50)
+  %52 = partial_apply [callee_guaranteed] %8(%48, %3) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %53 = partial_apply [callee_guaranteed] %10(%52) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %54 = builtin "fmul_FPIEEE32"(%50, %49) : $Builtin.FPIEEE32
+  %55 = struct $Float (%54)
+  %56 = partial_apply [callee_guaranteed] %8(%48, %51) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // function_ref pullback of Class.method()
+  %57 = function_ref @$s4test5ClassV6methodSfyFTJpSpSr : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Class.TangentVector
+  %58 = partial_apply [callee_guaranteed] %57(%47, %53, %56) : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Class.TangentVector
+  %59 = tuple (%55, %58)
+  return %59
+} // end sil function '$s4test5ClassV6methodSfyFTJrSpSr'
+
+
+///////////////////
+/// Test case 3 ///
+///////////////////
+
+/// This SIL corresponds to the following Swift:
+///
+/// @differentiable(reverse)
+/// func cond_tuple_var(_ x: Float) -> Float {
+///   // Convoluted function returning `x + x`.
+///   var y: (Float, Float) = (x, x)
+///   var z: (Float, Float) = (x + x, x - x)
+///   if x > 0 {
+///     let w = (x, x)
+///     y.0 = w.1
+///     y.1 = w.0
+///     z.0 = z.0 - y.0
+///     z.1 = z.1 + y.0
+///   } else {
+///     z = (1 * x, x)
+///   }
+///   return y.0 + y.1 - z.0 + z.1
+/// }
+
+enum _AD__$s4test14cond_tuple_varyS2fF_bb0__Pred__src_0_wrt_0 {
+}
+
+enum _AD__$s4test14cond_tuple_varyS2fF_bb1__Pred__src_0_wrt_0 {
+  case bb0(((Float) -> (Float, Float), (Float) -> (Float, Float)))
+}
+
+enum _AD__$s4test14cond_tuple_varyS2fF_bb2__Pred__src_0_wrt_0 {
+  case bb0(((Float) -> (Float, Float), (Float) -> (Float, Float)))
+}
+
+enum _AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0 {
+  case bb2((predecessor: _AD__$s4test14cond_tuple_varyS2fF_bb2__Pred__src_0_wrt_0, (Float) -> Float))
+  case bb1((predecessor: _AD__$s4test14cond_tuple_varyS2fF_bb1__Pred__src_0_wrt_0, (Float) -> (Float, Float), (Float) -> (Float, Float)))
+}
+
+sil @$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float) -> (Float, Float)
+sil @$sSf16_DifferentiationE12_vjpSubtract3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float) -> (Float, Float)
+
+// pullback of cond_tuple_var(_:)
+sil private [ossa] @$s4test14cond_tuple_varyS2fFTJpSpSr : $@convention(thin) (Float, @owned _AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0, @owned @callee_guaranteed (Float) -> (Float, Float), @owned @callee_guaranteed (Float) -> (Float, Float), @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float {
+bb0(%0 : $Float, %1 : @owned $_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0, %2 : @owned $@callee_guaranteed (Float) -> (Float, Float), %3 : @owned $@callee_guaranteed (Float) -> (Float, Float), %4 : @owned $@callee_guaranteed (Float) -> (Float, Float)):
+  %5 = float_literal $Builtin.FPIEEE32, 0x0 // 0
+  %10 = apply %4(%0) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %4
+  %12 = tuple_extract %10, 0
+  %13 = tuple_extract %10, 1
+  %14 = struct_extract %13, #Float._value
+  %15 = builtin "fadd_FPIEEE32"(%5, %14) : $Builtin.FPIEEE32
+  %17 = apply %3(%12) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %3
+  %19 = tuple_extract %17, 0
+  %20 = tuple_extract %17, 1
+  %21 = struct_extract %20, #Float._value
+  %22 = builtin "fadd_FPIEEE32"(%5, %21) : $Builtin.FPIEEE32
+  %24 = apply %2(%19) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %2
+  %26 = tuple_extract %24, 0
+  %27 = tuple_extract %24, 1
+  %28 = struct_extract %27, #Float._value
+  %29 = builtin "fadd_FPIEEE32"(%5, %28) : $Builtin.FPIEEE32
+  %31 = struct_extract %26, #Float._value
+  %32 = builtin "fadd_FPIEEE32"(%5, %31) : $Builtin.FPIEEE32
+  switch_enum %1, case #_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0.bb2!enumelt: bb1, case #_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0.bb1!enumelt: bb2
+
+bb1(%44 : @owned $(predecessor: _AD__$s4test14cond_tuple_varyS2fF_bb2__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> Float)):
+  (%45, %46) = destructure_tuple %44
+  %47 = builtin "fadd_FPIEEE32"(%15, %5) : $Builtin.FPIEEE32
+  %49 = builtin "fadd_FPIEEE32"(%22, %5) : $Builtin.FPIEEE32
+  %50 = struct $Float (%49)
+  %52 = apply %46(%50) : $@callee_guaranteed (Float) -> Float
+  destroy_value %46
+  %54 = struct_extract %52, #Float._value
+  %55 = builtin "fadd_FPIEEE32"(%54, %47) : $Builtin.FPIEEE32
+  %61 = unchecked_enum_data %45, #_AD__$s4test14cond_tuple_varyS2fF_bb2__Pred__src_0_wrt_0.bb0!enumelt
+  (%62, %63) = destructure_tuple %61
+  br bb3(%55, %32, %29, %5, %5, %62, %63)
+
+bb2(%65 : @owned $(predecessor: _AD__$s4test14cond_tuple_varyS2fF_bb1__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> (Float, Float), @callee_guaranteed (Float) -> (Float, Float))):
+  (%66, %67, %68) = destructure_tuple %65
+  %69 = builtin "fadd_FPIEEE32"(%15, %5) : $Builtin.FPIEEE32
+  %70 = struct $Float (%69)
+  %72 = apply %68(%70) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %68
+  %74 = tuple_extract %72, 0
+  %75 = tuple_extract %72, 1
+  %76 = struct_extract %74, #Float._value
+  %77 = builtin "fadd_FPIEEE32"(%76, %5) : $Builtin.FPIEEE32
+  %78 = struct_extract %75, #Float._value
+  %79 = builtin "fadd_FPIEEE32"(%78, %5) : $Builtin.FPIEEE32
+  %80 = builtin "fadd_FPIEEE32"(%32, %79) : $Builtin.FPIEEE32
+  %82 = builtin "fadd_FPIEEE32"(%5, %77) : $Builtin.FPIEEE32
+  %84 = builtin "fadd_FPIEEE32"(%22, %5) : $Builtin.FPIEEE32
+  %85 = struct $Float (%84)
+  %87 = apply %67(%85) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %67
+  %89 = tuple_extract %87, 0
+  %90 = tuple_extract %87, 1
+  %91 = struct_extract %89, #Float._value
+  %92 = builtin "fadd_FPIEEE32"(%91, %5) : $Builtin.FPIEEE32
+  %93 = struct_extract %90, #Float._value
+  %94 = builtin "fadd_FPIEEE32"(%93, %5) : $Builtin.FPIEEE32
+  %95 = builtin "fadd_FPIEEE32"(%80, %94) : $Builtin.FPIEEE32
+  %97 = builtin "fadd_FPIEEE32"(%5, %92) : $Builtin.FPIEEE32
+  %99 = builtin "fadd_FPIEEE32"(%29, %5) : $Builtin.FPIEEE32
+  %101 = builtin "fadd_FPIEEE32"(%99, %5) : $Builtin.FPIEEE32
+  %102 = builtin "fadd_FPIEEE32"(%95, %5) : $Builtin.FPIEEE32
+  %104 = builtin "fadd_FPIEEE32"(%102, %5) : $Builtin.FPIEEE32
+  %105 = builtin "fadd_FPIEEE32"(%101, %5) : $Builtin.FPIEEE32
+  %106 = builtin "fadd_FPIEEE32"(%104, %5) : $Builtin.FPIEEE32
+  %107 = builtin "fadd_FPIEEE32"(%105, %5) : $Builtin.FPIEEE32
+  %108 = builtin "fadd_FPIEEE32"(%106, %107) : $Builtin.FPIEEE32
+  %114 = unchecked_enum_data %66, #_AD__$s4test14cond_tuple_varyS2fF_bb1__Pred__src_0_wrt_0.bb0!enumelt
+  (%115, %116) = destructure_tuple %114
+  br bb3(%108, %5, %5, %97, %82, %115, %116)
+
+bb3(%118 : $Builtin.FPIEEE32, %119 : $Builtin.FPIEEE32, %120 : $Builtin.FPIEEE32, %121 : $Builtin.FPIEEE32, %122 : $Builtin.FPIEEE32, %123 : @owned $@callee_guaranteed (Float) -> (Float, Float), %124 : @owned $@callee_guaranteed (Float) -> (Float, Float)):
+  %125 = builtin "fadd_FPIEEE32"(%122, %5) : $Builtin.FPIEEE32
+  %126 = struct $Float (%125)
+  %127 = apply %124(%126) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %124
+  %129 = tuple_extract %127, 0
+  %130 = tuple_extract %127, 1
+  %131 = struct_extract %129, #Float._value
+  %132 = builtin "fadd_FPIEEE32"(%131, %118) : $Builtin.FPIEEE32
+  %133 = struct_extract %130, #Float._value
+  %134 = builtin "fadd_FPIEEE32"(%133, %132) : $Builtin.FPIEEE32
+  %135 = builtin "fadd_FPIEEE32"(%121, %5) : $Builtin.FPIEEE32
+  %136 = struct $Float (%135)
+  %137 = apply %123(%136) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %123
+  %139 = tuple_extract %137, 0
+  %140 = tuple_extract %137, 1
+  %141 = struct_extract %139, #Float._value
+  %142 = builtin "fadd_FPIEEE32"(%141, %134) : $Builtin.FPIEEE32
+  %143 = struct_extract %140, #Float._value
+  %144 = builtin "fadd_FPIEEE32"(%143, %142) : $Builtin.FPIEEE32
+  %145 = builtin "fadd_FPIEEE32"(%120, %144) : $Builtin.FPIEEE32
+  %146 = builtin "fadd_FPIEEE32"(%119, %145) : $Builtin.FPIEEE32
+  %147 = struct $Float (%146)
+  return %147
+} // end sil function '$s4test14cond_tuple_varyS2fFTJpSpSr'
+
+// reverse-mode derivative of cond_tuple_var(_:)
+sil hidden [ossa] @$s4test14cond_tuple_varyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+[global: ]
+bb0(%0 : $Float):
+  // CHECK:         sil private [ossa] @$s4test14cond_tuple_varyS2fFTJpSpSr067$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktl1_m5FZSf_M6SfcfU_0ef1_g4E12_i16Subtract3lhs3rhsk1_l1_mnl1_mo1_mP2U_ACTf1nnccc_n : $@convention(thin) (Float, @owned _AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0) -> Float {
+  // CHECK:         bb0(%0 : $Float, %1 : @owned $_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0):
+  // CHECK:           %[[#F2:]] = function_ref @$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float) -> (Float, Float)
+  // COMBINE-NOT:     = thin_to_thick_function
+  // CHECK:           %[[#F4:]] = function_ref @$sSf16_DifferentiationE12_vjpSubtract3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float) -> (Float, Float)
+  // COMBINE-NOT:     = thin_to_thick_function
+  // CHECK:           %[[#F8:]] = float_literal $Builtin.FPIEEE32, 0x0 // 0
+  // COMBINE:         %[[#F9:]] = apply %[[#F2]](%0) : $@convention(thin) (Float) -> (Float, Float)
+  // CHECK:           %[[#F11:]] = tuple_extract %[[#F9]] : $(Float, Float), 0
+  // COMBINE:         %[[#F15:]] = apply %[[#F4]](%[[#F11]]) : $@convention(thin) (Float) -> (Float, Float)
+  // CHECK:           %[[#F17:]] = tuple_extract %[[#F15]] : $(Float, Float), 0
+  // COMBINE:         %[[#]] = apply %[[#F2]](%[[#F17]]) : $@convention(thin) (Float) -> (Float, Float)
+  // CHECK:         {{^}}bb1{{.*}}:
+  // CHECK:         {{^}}bb2{{.*}}:
+  // CHECK:         {{^}}bb3{{.*}}:
+
+  // CHECK:         sil hidden [ossa] @$s4test14cond_tuple_varyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK:         bb0(%0 : $Float):
+  // CHECK:           %[[#G7:]] = function_ref @$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float) -> (Float, Float)
+  // CHECK:           %[[#G11:]] = function_ref @$sSf16_DifferentiationE12_vjpSubtract3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float) -> (Float, Float)
+  // CHECK:         bb1:
+  // CHECK:         bb2:
+  // CHECK:         bb3(%[[#G31:]] : @owned $_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0, %[[#]] : $Builtin.FPIEEE32, %[[#]] : $Builtin.FPIEEE32):
+
+  // COMBINE-NOT:     = thin_to_thick_function
+  // COMBINE-NOT:     = function_ref @$s4test14cond_tuple_varyS2fFTJpSpSr
+
+
+  // CHECK:           %[[#G41:]] = function_ref @$s4test14cond_tuple_varyS2fFTJpSpSr067$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktl1_m5FZSf_M6SfcfU_0ef1_g4E12_i16Subtract3lhs3rhsk1_l1_mnl1_mo1_mP2U_ACTf1nnccc_n : $@convention(thin) (Float, @owned _AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0) -> Float
+  // CHECK:           %[[#G42:]] = partial_apply [callee_guaranteed] %[[#G41]](%[[#G31]]) : $@convention(thin) (Float, @owned _AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0) -> Float
+  // CHECK:           %[[#G46:]] = tuple (%[[#]] : $Float, %[[#G42]] : $@callee_guaranteed (Float) -> Float)
+  // CHECK:           return %[[#G46]]
+
+  %4 = struct_extract %0, #Float._value
+  %5 = builtin "fadd_FPIEEE32"(%4, %4) : $Builtin.FPIEEE32
+  // function_ref closure #1 in static Float._vjpAdd(lhs:rhs:)
+  %7 = function_ref @$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float) -> (Float, Float)
+  %8 = thin_to_thick_function %7 to $@callee_guaranteed (Float) -> (Float, Float)
+  %9 = builtin "fsub_FPIEEE32"(%4, %4) : $Builtin.FPIEEE32
+  // function_ref closure #1 in static Float._vjpSubtract(lhs:rhs:)
+  %11 = function_ref @$sSf16_DifferentiationE12_vjpSubtract3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float) -> (Float, Float)
+  %12 = thin_to_thick_function %11 to $@callee_guaranteed (Float) -> (Float, Float)
+  %13 = float_literal $Builtin.FPIEEE32, 0x0 // 0
+  %14 = builtin "fcmp_olt_FPIEEE32"(%13, %4) : $Builtin.Int1
+  %15 = tuple (%8, %12)
+  cond_br %14, bb1, bb2
+
+bb1:
+  %17 = enum $_AD__$s4test14cond_tuple_varyS2fF_bb1__Pred__src_0_wrt_0, #_AD__$s4test14cond_tuple_varyS2fF_bb1__Pred__src_0_wrt_0.bb0!enumelt, %15
+  %22 = builtin "fsub_FPIEEE32"(%5, %4) : $Builtin.FPIEEE32
+  %23 = thin_to_thick_function %11 to $@callee_guaranteed (Float) -> (Float, Float)
+  %25 = builtin "fadd_FPIEEE32"(%9, %4) : $Builtin.FPIEEE32
+  %27 = thin_to_thick_function %7 to $@callee_guaranteed (Float) -> (Float, Float)
+  %28 = tuple $(predecessor: _AD__$s4test14cond_tuple_varyS2fF_bb1__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> (Float, Float), @callee_guaranteed (Float) -> (Float, Float)) (%17, %23, %27)
+  %29 = enum $_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0, #_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0.bb1!enumelt, %28
+  br bb3(%29, %25, %22)
+
+bb2:
+  %31 = enum $_AD__$s4test14cond_tuple_varyS2fF_bb2__Pred__src_0_wrt_0, #_AD__$s4test14cond_tuple_varyS2fF_bb2__Pred__src_0_wrt_0.bb0!enumelt, %15
+  %32 = float_literal $Builtin.FPIEEE32, 0x3F800000 // 1
+  %33 = struct $Float (%32)
+  %34 = builtin "fmul_FPIEEE32"(%32, %4) : $Builtin.FPIEEE32
+  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
+  %36 = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %37 = partial_apply [callee_guaranteed] %36(%0, %33) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // function_ref autodiff subset parameters thunk for pullback from @escaping @callee_guaranteed (@unowned Float) -> (@unowned Float, @unowned Float)
+  %38 = function_ref @$sS3fIegydd_TJSpSSUpSrUSUP : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %39 = partial_apply [callee_guaranteed] %38(%37) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %41 = tuple $(predecessor: _AD__$s4test14cond_tuple_varyS2fF_bb2__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> Float) (%31, %39)
+  %42 = enum $_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0, #_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0.bb2!enumelt, %41
+  br bb3(%42, %4, %34)
+
+bb3(%44 : @owned $_AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0, %45 : $Builtin.FPIEEE32, %46 : $Builtin.FPIEEE32):
+  %47 = thin_to_thick_function %7 to $@callee_guaranteed (Float) -> (Float, Float)
+  %48 = builtin "fsub_FPIEEE32"(%5, %46) : $Builtin.FPIEEE32
+  %49 = thin_to_thick_function %11 to $@callee_guaranteed (Float) -> (Float, Float)
+  %50 = builtin "fadd_FPIEEE32"(%48, %45) : $Builtin.FPIEEE32
+  %51 = struct $Float (%50)
+  %52 = thin_to_thick_function %7 to $@callee_guaranteed (Float) -> (Float, Float)
+  // function_ref pullback of cond_tuple_var(_:)
+  %53 = function_ref @$s4test14cond_tuple_varyS2fFTJpSpSr : $@convention(thin) (Float, @owned _AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0, @owned @callee_guaranteed (Float) -> (Float, Float), @owned @callee_guaranteed (Float) -> (Float, Float), @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %54 = partial_apply [callee_guaranteed] %53(%44, %47, %49, %52) : $@convention(thin) (Float, @owned _AD__$s4test14cond_tuple_varyS2fF_bb3__Pred__src_0_wrt_0, @owned @callee_guaranteed (Float) -> (Float, Float), @owned @callee_guaranteed (Float) -> (Float, Float), @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %55 = tuple (%51, %54)
+  return %55
+} // end sil function '$s4test14cond_tuple_varyS2fFTJrSpSr'
diff --git a/test/AutoDiff/SILOptimizer/closure_specialization/multi_bb_no_bte1.sil b/test/AutoDiff/SILOptimizer/closure_specialization/multi_bb_no_bte1.sil
new file mode 100644
index 0000000000000..86124d0e29aab
--- /dev/null
+++ b/test/AutoDiff/SILOptimizer/closure_specialization/multi_bb_no_bte1.sil
@@ -0,0 +1,159 @@
+/// Multi basic block VJP, pullback not accepting branch tracing enum argument.
+
+// RUN: %target-sil-opt -sil-print-types -autodiff-closure-specialization -sil-combine %s -o - | %FileCheck %s --check-prefixes=COMBINE,CHECK
+
+// REQUIRES: swift_in_compiler
+
+sil_stage canonical
+
+import Builtin
+import Swift
+import SwiftShims
+
+import _Differentiation
+
+/// This SIL corresponds to the following Swift:
+///
+/// struct Class: Differentiable {
+///   var stored: Float
+///   var optional: Float?
+///
+///   init(stored: Float, optional: Float?) {
+///     self.stored = stored
+///     self.optional = optional
+///   }
+///
+///   @differentiable(reverse)
+///   func method() -> Float {
+///     let c: Class
+///     do {
+///       let tmp = Class(stored: 1 * stored, optional: optional)
+///       let tuple = (tmp, tmp)
+///       c = tuple.0
+///     }
+///     if let x = c.optional {
+///       return x * c.stored
+///     }
+///     return 1 * c.stored
+///   }
+/// }
+///
+/// @differentiable(reverse)
+/// func methodWrapper(_ x: Class) -> Float {
+///   x.method()
+/// }
+
+struct Class : Differentiable {
+  @_hasStorage var stored: Float { get set }
+  @_hasStorage @_hasInitialValue var optional: Float? { get set }
+  init(stored: Float, optional: Float?)
+  @differentiable(reverse, wrt: self)
+  func method() -> Float
+  struct TangentVector : AdditiveArithmetic, Differentiable {
+    @_hasStorage var stored: Float { get set }
+    @_hasStorage var optional: Optional<Float>.TangentVector { get set }
+    static func + (lhs: Class.TangentVector, rhs: Class.TangentVector) -> Class.TangentVector
+    static func - (lhs: Class.TangentVector, rhs: Class.TangentVector) -> Class.TangentVector
+    typealias TangentVector = Class.TangentVector
+    @_implements(Equatable, ==(_:_:)) static func __derived_struct_equals(_ a: Class.TangentVector, _ b: Class.TangentVector) -> Bool
+    init(stored: Float, optional: Optional<Float>.TangentVector)
+    static var zero: Class.TangentVector { get }
+  }
+  mutating func move(by offset: Class.TangentVector)
+}
+
+enum _AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0 {
+  case bb0(((Float) -> Float, (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)))
+}
+
+enum _AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0 {
+  case bb0(((Float) -> Float, (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)))
+}
+
+enum _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0 {
+  case bb2((predecessor: _AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0, (Float) -> Float))
+  case bb1((predecessor: _AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0, (Float) -> (Float, Float)))
+}
+
+sil @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+sil [transparent] [thunk] @$sS3fIegydd_TJSpSSUpSrUSUP : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+sil @$s4test5ClassV6stored8optionalACSf_SfSgtcfCTJpSSUpSr : $@convention(thin) (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)
+sil @$s4test5ClassV6methodSfyFTJpSpSr : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector
+
+// pullback of methodWrapper(_:)
+sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @$s4test13methodWrapperySfAA5ClassVFTJpSpSr : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Class.TangentVector) -> Class.TangentVector {
+bb0(%0 : $Float, %1 : @owned $@callee_guaranteed (Float) -> Class.TangentVector):
+  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> Class.TangentVector
+  destroy_value %1
+  return %2
+} // end sil function '$s4test13methodWrapperySfAA5ClassVFTJpSpSr'
+
+// reverse-mode derivative of methodWrapper(_:)
+sil hidden [ossa] @$s4test13methodWrapperySfAA5ClassVFTJrSpSr : $@convention(thin) (Class) -> (Float, @owned @callee_guaranteed (Float) -> Class.TangentVector) {
+bb0(%0 : $Class):
+  // CHECK:         sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @$s4test13methodWrapperySfAA5ClassVFTJpSpSr08$s4test5D19V6methodSfyFTJpSpSr4main05_AD__edfG24F_bb3__Pred__src_0_wrt_0OTf1nc_n : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector {
+  // CHECK:         bb0(%0 : $Float, %1 : @owned $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0):
+  // CHECK:           %[[#B2:]] = function_ref @$s4test5ClassV6methodSfyFTJpSpSr : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector
+  // COMBINE-NOT:     partial_apply
+  // COMBINE:         %[[#B4:]] = apply %[[#B2]](%0, %1) : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector
+  // CHECK:           return %[[#B4]]
+
+  // CHECK:         sil hidden [ossa] @$s4test13methodWrapperySfAA5ClassVFTJrSpSr : $@convention(thin) (Class) -> (Float, @owned @callee_guaranteed (Float) -> Class.TangentVector) {
+  // CHECK:         bb3(%[[#C33:]] : $Float, %[[#C34:]] : @owned $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0):
+  // COMBINE-NOT:     function_ref @$s4test5ClassV6methodSfyFTJpSpSr
+  // COMBINE-NOT:     partial_apply
+  // COMBINE-NOT:     function_ref @$s4test13methodWrapperySfAA5ClassVFTJpSpSr
+  // CHECK:           %[[#C39:]] = function_ref @$s4test13methodWrapperySfAA5ClassVFTJpSpSr08$s4test5D19V6methodSfyFTJpSpSr4main05_AD__edfG24F_bb3__Pred__src_0_wrt_0OTf1nc_n : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector
+  // CHECK:           %[[#C40:]] = partial_apply [callee_guaranteed] %[[#C39]](%[[#C34]]) : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector
+  // CHECK:           %[[#C42:]] = tuple (%[[#C33]] : $Float, %[[#C40]] : $@callee_guaranteed (Float) -> Class.TangentVector)
+  // CHECK:           return %[[#C42]]
+
+  %3 = float_literal $Builtin.FPIEEE32, 0x3F800000 // 1
+  %4 = struct $Float (%3)
+  %5 = struct_extract %0, #Class.stored
+  %6 = struct_extract %5, #Float._value
+  %7 = builtin "fmul_FPIEEE32"(%3, %6) : $Builtin.FPIEEE32
+  %8 = struct $Float (%7)
+  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
+  %9 = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %10 = partial_apply [callee_guaranteed] %9(%5, %4) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // function_ref autodiff subset parameters thunk for pullback from @escaping @callee_guaranteed (@unowned Float) -> (@unowned Float, @unowned Float)
+  %11 = function_ref @$sS3fIegydd_TJSpSSUpSrUSUP : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %12 = partial_apply [callee_guaranteed] %11(%10) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %13 = struct_extract %0, #Class.optional
+  // function_ref pullback of Class.init(stored:optional:)
+  %26 = function_ref @$s4test5ClassV6stored8optionalACSf_SfSgtcfCTJpSSUpSr : $@convention(thin) (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)
+  %27 = thin_to_thick_function %26 to $@callee_guaranteed (Class.TangentVector) -> (Float, Optional<Float>.TangentVector)
+  %28 = tuple (%12, %27)
+  switch_enum %13, case #Optional.some!enumelt: bb1, case #Optional.none!enumelt: bb2
+
+bb1(%30 : $Float):
+  %31 = enum $_AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0, #_AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0.bb0!enumelt, %28
+  %33 = struct_extract %30, #Float._value
+  %34 = builtin "fmul_FPIEEE32"(%33, %7) : $Builtin.FPIEEE32
+  %35 = struct $Float (%34)
+  %36 = partial_apply [callee_guaranteed] %9(%8, %30) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %37 = tuple $(predecessor: _AD__$s4test5ClassV6methodSfyF_bb1__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> (Float, Float)) (%31, %36)
+  %38 = enum $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, #_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0.bb1!enumelt, %37
+  br bb3(%35, %38)
+
+bb2:
+  %40 = enum $_AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0, #_AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0.bb0!enumelt, %28
+  %41 = builtin "fmul_FPIEEE32"(%3, %7) : $Builtin.FPIEEE32
+  %42 = struct $Float (%41)
+  %43 = partial_apply [callee_guaranteed] %9(%8, %4) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %44 = partial_apply [callee_guaranteed] %11(%43) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %45 = tuple $(predecessor: _AD__$s4test5ClassV6methodSfyF_bb2__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> Float) (%40, %44)
+  %46 = enum $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0, #_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0.bb2!enumelt, %45
+  br bb3(%42, %46)
+
+bb3(%48 : $Float, %49 : @owned $_AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0):
+  // function_ref pullback of Class.method()
+  %50 = function_ref @$s4test5ClassV6methodSfyFTJpSpSr : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector
+  %51 = partial_apply [callee_guaranteed] %50(%49) : $@convention(thin) (Float, @owned _AD__$s4test5ClassV6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector
+  // function_ref pullback of methodWrapper(_:)
+  %52 = function_ref @$s4test13methodWrapperySfAA5ClassVFTJpSpSr : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Class.TangentVector) -> Class.TangentVector
+  %53 = partial_apply [callee_guaranteed] %52(%51) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Class.TangentVector) -> Class.TangentVector
+  %54 = tuple (%48, %53)
+  return %54
+} // end sil function '$s4test13methodWrapperySfAA5ClassVFTJrSpSr'
diff --git a/test/AutoDiff/SILOptimizer/closure_specialization/multi_bb_no_bte2.sil b/test/AutoDiff/SILOptimizer/closure_specialization/multi_bb_no_bte2.sil
new file mode 100644
index 0000000000000..3316e069465fd
--- /dev/null
+++ b/test/AutoDiff/SILOptimizer/closure_specialization/multi_bb_no_bte2.sil
@@ -0,0 +1,182 @@
+/// Multi basic block VJP, pullback not accepting branch tracing enum argument.
+
+// RUN: %target-sil-opt -sil-print-types -autodiff-closure-specialization -sil-combine %s -o - | %FileCheck %s --check-prefixes=COMBINE,CHECK
+
+// REQUIRES: swift_in_compiler
+
+/// _ArrayBuffer is part of the ObjC runtime interop.
+// REQUIRES: objc_interop
+// REQUIRES: CPU=x86_64 || CPU=arm64
+
+sil_stage canonical
+
+import Builtin
+import Swift
+import SwiftShims
+
+import _Differentiation
+
+sil [_semantics "array.append_contentsOf"] @$sSa6append10contentsOfyqd__n_t7ElementQyd__RszSTRd__lFSf_SaySfGTg5 : $@convention(method) (@owned Array<Float>, @inout Array<Float>) -> ()
+
+sil @$sSa16_DifferentiationAA14DifferentiableRzlE15_vjpConcatenateySayxG5value_SaA2aBRzlE0B4ViewVy13TangentVectorQz_G_AJtAJc8pullbacktAD_ADtFZAKL_yAJ_AJtAjaBRzlFSf_Tg5 : $@convention(thin) (@guaranteed Array<Float>.DifferentiableView, @guaranteed Array<Float>, @guaranteed Array<Float>) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+
+sil [transparent] [reabstraction_thunk] @$sSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVy13TangentVectorAaBPQz_GA2HIeggoo_A3HIeggoo_AaBRzlTRSf_Tg5 : $@convention(thin) (@guaranteed Array<Float>.DifferentiableView, @guaranteed @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+
+sil [_semantics "array.check_subscript"] @$sSa15_checkSubscript_20wasNativeTypeCheckeds16_DependenceTokenVSi_SbtFSf_Tg5 : $@convention(method) (Int, Bool, @guaranteed Array<Float>) -> _DependenceToken
+
+sil [transparent] [thunk] @$sSa16_DifferentiationAA14DifferentiableRzlE13_vjpSubscript5indexx5value_SaA2aBRzlE0B4ViewVy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaBRzlFSf_TG5 : $@convention(thin) (@in_guaranteed Float, @guaranteed Array<Float>, Int) -> @owned Array<Float>.DifferentiableView
+
+sil [transparent] [thunk] @$s13TangentVector16_Differentiation14DifferentiablePQzSaA2bCRzlE0D4ViewVyAE_GIegno_AeHIegno_AbCRzlTRSf_TG5 : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView) -> @owned Array<Float>.DifferentiableView
+
+// specialized pullback of sum1(_:_:)
+sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @$s4test4sum1ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyd8_GIegno_D10AEIegyo_TRSfSa01_F0AE0H0RzlE0hL0VySf_GIegno_Tf1nnc_n : $@convention(thin) (Float, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned @callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView) {
+bb0(%0 : $Float, %1 : @owned $@callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), %2 : @owned $@callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView):
+  %3 = float_literal $Builtin.FPIEEE32, 0x0 // 0
+  %4 = struct_extract %0, #Float._value
+  %5 = builtin "fadd_FPIEEE32"(%3, %4) : $Builtin.FPIEEE32
+  %6 = struct $Float (%5)
+  %7 = alloc_stack $Float
+  store %6 to [trivial] %7
+  %9 = apply %2(%7) : $@callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView
+  destroy_value %2
+  dealloc_stack %7
+  %13 = apply %1(%9) : $@callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  destroy_value %9
+  destroy_value %1
+  return %13
+} // end sil function '$s4test4sum1ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyd8_GIegno_D10AEIegyo_TRSfSa01_F0AE0H0RzlE0hL0VySf_GIegno_Tf1nnc_n'
+
+// reverse-mode derivative of sum1(_:_:)
+sil hidden [ossa] @$s4test4sum1ySfSaySfG_ACtFTJrSSpSr : $@convention(thin) (@guaranteed Array<Float>, @guaranteed Array<Float>) -> (Float, @owned @callee_guaranteed (Float) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)) {
+bb0(%0 : @guaranteed $Array<Float>, %1 : @guaranteed $Array<Float>):
+  // CHECK:         sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @$s4test4sum1ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyd8_GIegno_D10AEIegyo_TRSfSa01_F0AE0H0RzlE0hL0VySf_GIegno_Tf1nnc_n0ce1_fghi39E13_vjpSubscript5indexx5value_SaA2aBRzljkl48Vy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaV7FSf_TG5ACSiTf1nnc_n : $@convention(thin) (Float, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned Array<Float>, Int) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView) {
+  // CHECK:         bb0(%0 : $Float, %1 : @owned $@callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), %2 : @owned $Array<Float>, %3 : $Int):
+  // CHECK:           %[[#D6:]] = function_ref @$s13TangentVector16_Differentiation14DifferentiablePQzSaA2bCRzlE0D4ViewVyAE_GIegno_AeHIegno_AbCRzlTRSf_TG5 : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView) -> @owned Array<Float>.DifferentiableView
+  // CHECK:           %[[#D4:]] = function_ref @$sSa16_DifferentiationAA14DifferentiableRzlE13_vjpSubscript5indexx5value_SaA2aBRzlE0B4ViewVy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaBRzlFSf_TG5 : $@convention(thin) (@in_guaranteed Float, @guaranteed Array<Float>, Int) -> @owned Array<Float>.DifferentiableView
+  // CHECK:           %[[#D5:]] = partial_apply [callee_guaranteed] %[[#D4]](%2, %3) : $@convention(thin) (@in_guaranteed Float, @guaranteed Array<Float>, Int) -> @owned Array<Float>.DifferentiableView
+  // CHECK:           store %[[#D11:]] to [trivial] %[[#D12:]] : $*Float
+  // COMBINE:         %[[#D14:]] = apply %[[#D6]](%[[#D12]], %[[#D5]]) : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView) -> @owned Array<Float>.DifferentiableView
+  // COMBINE:         destroy_value %[[#D5]] : $@callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView
+  // CHECK:           %[[#D17:]] = apply %1(%[[#D14]]) : $@callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  // CHECK:           return %[[#D17]] : $(Array<Float>.DifferentiableView, Array<Float>.DifferentiableView)
+
+  // CHECK:         sil hidden [ossa] @$s4test4sum1ySfSaySfG_ACtFTJrSSpSr : $@convention(thin) (@guaranteed Array<Float>, @guaranteed Array<Float>) -> (Float, @owned @callee_guaranteed (Float) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)) {
+  // CHECK:           (%[[#]], %[[#E42:]]) = destructure_tuple %[[#]] : $(Array<Float>, @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView))
+  // CHECK:         bb8:
+
+
+  // COMBINE-NOT:     function_ref @$sSa16_DifferentiationAA14DifferentiableRzlE13_vjpSubscript5indexx5value_SaA2aBRzlE0B4ViewVy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaBRzlFSf_TG5
+  // COMBINE-NOT:     partial_apply
+  // COMBINE-NOT:     function_ref @$s13TangentVector16_Differentiation14DifferentiablePQzSaA2bCRzlE0D4ViewVyAE_GIegno_AeHIegno_AbCRzlTRSf_TG5
+  // COMBINE-NOT:     partial_apply
+  // COMBINE-NOT:     function_ref @$s4test4sum1ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyd8_GIegno_D10AEIegyo_TRSfSa01_F0AE0H0RzlE0hL0VySf_GIegno_Tf1nnc_n
+
+  // CHECK:           %[[#E52:]] = function_ref @$s4test4sum1ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyd8_GIegno_D10AEIegyo_TRSfSa01_F0AE0H0RzlE0hL0VySf_GIegno_Tf1nnc_n0ce1_fghi39E13_vjpSubscript5indexx5value_SaA2aBRzljkl48Vy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaV7FSf_TG5ACSiTf1nnc_n : $@convention(thin) (Float, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned Array<Float>, Int) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  // CHECK:           %[[#E53:]] = partial_apply [callee_guaranteed] %[[#E52]](%[[#E42]], %[[#]], %[[#]]) : $@convention(thin) (Float, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned Array<Float>, Int) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  // CHECK:           %[[#E55:]] = tuple (%[[#]] : $Float, %[[#E53]] : $@callee_guaranteed (Float) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView))
+  // CHECK:           return %[[#E55]]
+
+  %4 = alloc_stack [var_decl] $Array<Float>
+  %5 = copy_value %0
+  store %5 to [init] %4
+  // function_ref specialized Array.append<A>(contentsOf:)
+  %6 = function_ref @$sSa6append10contentsOfyqd__n_t7ElementQyd__RszSTRd__lFSf_SaySfGTg5 : $@convention(method) (@owned Array<Float>, @inout Array<Float>) -> ()
+  %7 = copy_value %1
+  %9 = apply %6(%7, %4) : $@convention(method) (@owned Array<Float>, @inout Array<Float>) -> ()
+  %10 = load [take] %4
+  dealloc_stack %4
+  // function_ref specialized pullback #1 <A>(_:) in static Array<A>._vjpConcatenate(_:_:)
+  %12 = function_ref @$sSa16_DifferentiationAA14DifferentiableRzlE15_vjpConcatenateySayxG5value_SaA2aBRzlE0B4ViewVy13TangentVectorQz_G_AJtAJc8pullbacktAD_ADtFZAKL_yAJ_AJtAjaBRzlFSf_Tg5 : $@convention(thin) (@guaranteed Array<Float>.DifferentiableView, @guaranteed Array<Float>, @guaranteed Array<Float>) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  %12a = copy_value %0
+  %12b = copy_value %1
+  %13 = partial_apply [callee_guaranteed] %12(%12a, %12b) : $@convention(thin) (@guaranteed Array<Float>.DifferentiableView, @guaranteed Array<Float>, @guaranteed Array<Float>) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  // function_ref specialized thunk for @escaping @callee_guaranteed (@guaranteed [A.Differentiable.TangentVector]<A>.DifferentiableView) -> (@owned [A.Differentiable.TangentVector]<A>.DifferentiableView, @owned [A.Differentiable.TangentVector]<A>.DifferentiableView)
+  %14 = function_ref @$sSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVy13TangentVectorAaBPQz_GA2HIeggoo_A3HIeggoo_AaBRzlTRSf_Tg5 : $@convention(thin) (@guaranteed Array<Float>.DifferentiableView, @guaranteed @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  %15 = partial_apply [callee_guaranteed] %14(%13) : $@convention(thin) (@guaranteed Array<Float>.DifferentiableView, @guaranteed @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  %16 = convert_function %15 to $@callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@guaranteed τ_0_0) -> (@owned τ_0_1, @owned τ_0_2) for <Array<Float>.DifferentiableView, Array<Float>.DifferentiableView, Array<Float>.DifferentiableView>
+  %17 = tuple (%10, %16)
+  %18 = unchecked_value_cast %17 to $(Array<Float>, @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView))
+  (%19, %121) = destructure_tuple %18
+  %21 = integer_literal $Builtin.Int64, 0
+  %22 = struct $Int (%21)
+  %23 = integer_literal $Builtin.Int1, -1
+  %24 = struct $Bool (%23)
+  // function_ref specialized Array._checkSubscript(_:wasNativeTypeChecked:)
+  %25 = function_ref @$sSa15_checkSubscript_20wasNativeTypeCheckeds16_DependenceTokenVSi_SbtFSf_Tg5 : $@convention(method) (Int, Bool, @guaranteed Array<Float>) -> _DependenceToken
+  %26 = apply %25(%22, %24, %19) : $@convention(method) (Int, Bool, @guaranteed Array<Float>) -> _DependenceToken
+  %b = begin_borrow %19
+  %27 = struct_extract %b, #Array._buffer
+  %28 = struct_extract %27, #_ArrayBuffer._storage
+  %29 = string_literal utf8 "Swift/BridgeStorage.swift"
+  %30 = integer_literal $Builtin.Word, 25
+  %31 = builtin "ptrtoint_Word"(%29) : $Builtin.Word
+  %32 = integer_literal $Builtin.Int8, 2
+  %33 = struct $StaticString (%31, %30, %32)
+  %34 = string_literal utf8 ""
+  %35 = integer_literal $Builtin.Word, 0
+  %36 = builtin "ptrtoint_Word"(%34) : $Builtin.Word
+  %37 = struct $StaticString (%36, %35, %32)
+  %38 = struct_extract %28, #_BridgeStorage.rawValue
+  %39 = classify_bridge_object %38
+  %40 = tuple_extract %39, 0
+  %41 = tuple_extract %39, 1
+  %42 = builtin "or_Int1"(%40, %41) : $Builtin.Int1
+  %43 = integer_literal $Builtin.Int1, 0
+  %44 = builtin "int_expect_Int1"(%42, %43) : $Builtin.Int1
+  cond_br %44, bb1, bb2
+
+bb1:
+  unreachable
+
+bb2:
+  %57 = bridge_object_to_word %38 to $Builtin.Word
+  %58 = builtin "zextOrBitCast_Word_Int64"(%57) : $Builtin.Int64
+  %59 = integer_literal $Builtin.Int64, 9151314442816847879
+  %60 = builtin "and_Int64"(%58, %59) : $Builtin.Int64
+  %61 = builtin "cmp_eq_Int64"(%60, %21) : $Builtin.Int1
+  %62 = builtin "int_expect_Int1"(%61, %23) : $Builtin.Int1
+  cond_br %62, bb4, bb3
+
+bb3:
+  unreachable
+
+bb4:
+  %75 = unchecked_ref_cast %38 to $__ContiguousArrayStorageBase
+  %76 = integer_literal $Builtin.Word, 24
+  %77 = ref_element_addr %75, #__ContiguousArrayStorageBase.countAndCapacity
+  %78 = struct_element_addr %77, #_ArrayBody._storage
+  %79 = struct_element_addr %78, #_SwiftArrayBodyStorage.count
+  %80 = struct_element_addr %79, #Int._value
+  %81 = load [trivial] %80
+  %82 = builtin "cmp_slt_Int64"(%81, %21) : $Builtin.Int1
+  %83 = builtin "int_expect_Int1"(%82, %43) : $Builtin.Int1
+  cond_br %83, bb6, bb7
+
+bb5:
+  unreachable
+
+bb6:
+  unreachable
+
+bb7:
+  %117 = builtin "assumeNonNegative_Int64"(%81) : $Builtin.Int64
+  %118 = builtin "cmp_slt_Int64"(%21, %117) : $Builtin.Int1
+  %119 = builtin "int_expect_Int1"(%118, %23) : $Builtin.Int1
+  cond_br %119, bb8, bb5
+
+bb8:
+  %122 = ref_tail_addr [immutable] %75, $Float
+  %123 = load [trivial] %122
+  end_borrow %b
+  // function_ref specialized pullback #1 <A>(_:) in Array<A>._vjpSubscript(index:)
+  %124 = function_ref @$sSa16_DifferentiationAA14DifferentiableRzlE13_vjpSubscript5indexx5value_SaA2aBRzlE0B4ViewVy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaBRzlFSf_TG5 : $@convention(thin) (@in_guaranteed Float, @guaranteed Array<Float>, Int) -> @owned Array<Float>.DifferentiableView
+  %125 = partial_apply [callee_guaranteed] %124(%19, %22) : $@convention(thin) (@in_guaranteed Float, @guaranteed Array<Float>, Int) -> @owned Array<Float>.DifferentiableView
+  // function_ref specialized thunk for @escaping @callee_guaranteed (@in_guaranteed A.Differentiable.TangentVector) -> (@owned [A.Differentiable.TangentVector]<A>.DifferentiableView)
+  %126 = function_ref @$s13TangentVector16_Differentiation14DifferentiablePQzSaA2bCRzlE0D4ViewVyAE_GIegno_AeHIegno_AbCRzlTRSf_TG5 : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView) -> @owned Array<Float>.DifferentiableView
+  %127 = partial_apply [callee_guaranteed] %126(%125) : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView) -> @owned Array<Float>.DifferentiableView
+  // function_ref specialized pullback of sum1(_:_:)
+  %128 = function_ref @$s4test4sum1ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyd8_GIegno_D10AEIegyo_TRSfSa01_F0AE0H0RzlE0hL0VySf_GIegno_Tf1nnc_n : $@convention(thin) (Float, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned @callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  %129 = partial_apply [callee_guaranteed] %128(%121, %127) : $@convention(thin) (Float, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned @callee_guaranteed (@in_guaranteed Float) -> @owned Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  %130 = tuple (%123, %129)
+  return %130
+} // end sil function '$s4test4sum1ySfSaySfG_ACtFTJrSSpSr'
diff --git a/test/AutoDiff/SILOptimizer/closure_specialization/single_bb.sil b/test/AutoDiff/SILOptimizer/closure_specialization/single_bb.sil
new file mode 100644
index 0000000000000..cc31016a187bb
--- /dev/null
+++ b/test/AutoDiff/SILOptimizer/closure_specialization/single_bb.sil
@@ -0,0 +1,376 @@
+// RUN: %target-sil-opt -sil-print-types -autodiff-closure-specialization -sil-combine %s -o - | %FileCheck %s --check-prefixes=COMBINE,CHECK
+
+// REQUIRES: swift_in_compiler
+
+sil_stage canonical
+
+import Builtin
+import Swift
+import SwiftShims
+
+import _Differentiation
+
+////////////////////////////////////////////////////////////////
+// Single closure call site where closure is passed as @owned //
+////////////////////////////////////////////////////////////////
+sil @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+
+sil private [ossa] @$pullback_f : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float {
+bb0(%0 : $Float, %1 : @owned $@callee_guaranteed (Float) -> (Float, Float)):
+  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %1
+  %4 = tuple_extract %2 : $(Float, Float), 0
+  %5 = tuple_extract %2 : $(Float, Float), 1
+  %6 = struct_extract %5 : $Float, #Float._value
+  %7 = struct_extract %4 : $Float, #Float._value
+  %8 = builtin "fadd_FPIEEE32"(%6 : $Builtin.FPIEEE32, %7 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  %9 = struct $Float (%8 : $Builtin.FPIEEE32)
+  return %9 : $Float
+}
+
+// reverse-mode derivative of f(_:)
+sil hidden [ossa] @$s4test1fyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+bb0(%0 : $Float):
+  // CHECK:         sil private [ossa] @$s11$pullback_f12$vjpMultiplyS2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float {
+  // CHECK:         bb0(%0 : $Float, %1 : $Float, %2 : $Float):
+  // CHECK:           %[[#A2:]] = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // COMBINE:         %[[#]] = apply %[[#A2]](%0, %1, %2) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+
+  // CHECK:         sil hidden [ossa] @$s4test1fyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK:         bb0(%0 : $Float):
+  // CHECK:           %[[#A4:]] = struct_extract %0 : $Float, #Float._value
+  // CHECK:           %[[#A5:]] = builtin "fmul_FPIEEE32"(%[[#A4]] : $Builtin.FPIEEE32, %[[#A4]] : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  // CHECK:           %[[#A6:]] = struct $Float (%[[#A5]] : $Builtin.FPIEEE32)
+  // COMBINE-NOT:     function_ref @$vjpMultiply
+  // CHECK:           %[[#A7:]] = function_ref @$s11$pullback_f12$vjpMultiplyS2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float
+  // CHECK:           %[[#A8:]] = partial_apply [callee_guaranteed] %[[#A7]](%0, %0) : $@convention(thin) (Float, Float, Float) -> Float
+  // CHECK:           %[[#A9:]] = tuple (%[[#A6]] : $Float, %[[#A8]] : $@callee_guaranteed (Float) -> Float)
+  // CHECK:           return %[[#A9]]
+
+  %2 = struct_extract %0 : $Float, #Float._value
+  %3 = builtin "fmul_FPIEEE32"(%2 : $Builtin.FPIEEE32, %2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  %4 = struct $Float (%3 : $Builtin.FPIEEE32)
+  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
+  %5 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %6 = partial_apply [callee_guaranteed] %5(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // function_ref pullback of f(_:)
+  %7 = function_ref @$pullback_f : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %8 = partial_apply [callee_guaranteed] %7(%6) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %9 = tuple (%4 : $Float, %8 : $@callee_guaranteed (Float) -> Float)
+  return %9 : $(Float, @callee_guaranteed (Float) -> Float)
+}
+
+/////////////////////////////////////////////////////////////////////
+// Single closure call site where closure is passed as @guaranteed //
+/////////////////////////////////////////////////////////////////////
+sil private [ossa] @$pullback_k : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float {
+bb0(%0 : $Float, %1 : @guaranteed $@callee_guaranteed (Float) -> (Float, Float)):
+  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> (Float, Float)
+  %3 = tuple_extract %2 : $(Float, Float), 0
+  %4 = tuple_extract %2 : $(Float, Float), 1
+  %5 = struct_extract %4 : $Float, #Float._value
+  %6 = struct_extract %3 : $Float, #Float._value
+  %7 = builtin "fadd_FPIEEE32"(%5 : $Builtin.FPIEEE32, %6 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  %8 = struct $Float (%7 : $Builtin.FPIEEE32)
+  return %8 : $Float
+} // end sil function '$pullback_k'
+
+// reverse-mode derivative of k(_:)
+sil hidden [ossa] @$s4test1kyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+bb0(%0 : $Float):
+  // CHECK:         sil private [ossa] @$s11$pullback_k12$vjpMultiplyS2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float {
+  // CHECK:         bb0(%0 : $Float, %1 : $Float, %2 : $Float):
+  // CHECK:           %[[#B2:]] = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // COMBINE:         %[[#]] = apply %[[#B2]](%0, %1, %2) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+
+  // CHECK:         sil hidden [ossa] @$s4test1kyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK:         bb0(%0 : $Float):
+  // CHECK:           %[[#B4:]] = struct_extract %0 : $Float, #Float._value
+  // CHECK:           %[[#B5:]] = builtin "fmul_FPIEEE32"(%[[#B4]] : $Builtin.FPIEEE32, %[[#B4]] : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  // CHECK:           %[[#B6:]] = struct $Float (%[[#B5]] : $Builtin.FPIEEE32)
+  // COMBINE-NOT:     function_ref @$vjpMultiply
+  // CHECK:           %[[#B7:]] = function_ref @$s11$pullback_k12$vjpMultiplyS2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float
+  // CHECK:           %[[#B8:]] = partial_apply [callee_guaranteed] %[[#B7]](%0, %0) : $@convention(thin) (Float, Float, Float) -> Float
+  // CHECK:           %[[#B9:]] = tuple (%[[#B6]] : $Float, %[[#B8]] : $@callee_guaranteed (Float) -> Float)
+  // CHECK:           return %[[#B9]]
+
+  %2 = struct_extract %0 : $Float, #Float._value
+  %3 = builtin "fmul_FPIEEE32"(%2 : $Builtin.FPIEEE32, %2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  %4 = struct $Float (%3 : $Builtin.FPIEEE32)
+  // function_ref $vjpMultiply
+  %5 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %6 = partial_apply [callee_guaranteed] %5(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // function_ref $pullback_k
+  %7 = function_ref @$pullback_k : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %8 = partial_apply [callee_guaranteed] %7(%6) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %10 = tuple (%4 : $Float, %8 : $@callee_guaranteed (Float) -> Float)
+  return %10 : $(Float, @callee_guaranteed (Float) -> Float)
+} // end sil function '$s4test1kyS2fFTJrSpSr'
+
+///////////////////////////////
+// Multiple closure callsite //
+///////////////////////////////
+sil @$vjpSin : $@convention(thin) (Float, Float) -> Float
+sil @$vjpCos : $@convention(thin) (Float, Float) -> Float
+
+// pullback of g(_:)
+sil private [ossa] @$pullback_g : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float {
+bb0(%0 : $Float, %1 : @owned $@callee_guaranteed (Float) -> Float, %2 : @owned $@callee_guaranteed (Float) -> Float, %3 : @owned $@callee_guaranteed (Float) -> (Float, Float)):
+  %4 = apply %3(%0) : $@callee_guaranteed (Float) -> (Float, Float)
+  destroy_value %3 : $@callee_guaranteed (Float) -> (Float, Float)
+  %6 = tuple_extract %4 : $(Float, Float), 0
+  %7 = tuple_extract %4 : $(Float, Float), 1
+  %8 = apply %2(%7) : $@callee_guaranteed (Float) -> Float
+  destroy_value %2 : $@callee_guaranteed (Float) -> Float
+  %10 = apply %1(%6) : $@callee_guaranteed (Float) -> Float
+  destroy_value %1 : $@callee_guaranteed (Float) -> Float
+  %12 = struct_extract %8 : $Float, #Float._value
+  %13 = struct_extract %10 : $Float, #Float._value
+  %14 = builtin "fadd_FPIEEE32"(%13 : $Builtin.FPIEEE32, %12 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  %15 = struct $Float (%14 : $Builtin.FPIEEE32)
+  return %15 : $Float
+}
+
+// reverse-mode derivative of g(_:)
+sil hidden [ossa] @$s4test1gyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+bb0(%0 : $Float):
+  // CHECK:         sil private [ossa] @$s11$pullback_g7$vjpSinSf0B3CosSf0B8MultiplyS2fTf1nccc_n : $@convention(thin) (Float, Float, Float, Float, Float) -> Float {
+  // CHECK:         bb0(%0 : $Float, %1 : $Float, %2 : $Float, %3 : $Float, %4 : $Float):
+  // CHECK:           %[[#C4:]] = function_ref @$vjpSin : $@convention(thin) (Float, Float) -> Float
+  // CHECK:           %[[#C6:]] = function_ref @$vjpCos : $@convention(thin) (Float, Float) -> Float
+  // CHECK:           %[[#C8:]] = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // COMBINE:         %[[#]] = apply %[[#C8]](%0, %3, %4) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // COMBINE:         %[[#]] = apply %[[#C6]](%[[#]], %2) : $@convention(thin) (Float, Float) -> Float
+  // COMBINE:         %[[#]] = apply %[[#C4]](%[[#]], %1) : $@convention(thin) (Float, Float) -> Float
+
+  // CHECK:         sil hidden [ossa] @$s4test1gyS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK:         bb0(%0 : $Float):
+  // CHECK:           %[[#C10:]] = struct_extract %0 : $Float, #Float._value
+  // CHECK:           %[[#C11:]] = builtin "int_sin_FPIEEE32"(%[[#C10]] : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  // CHECK:           %[[#C12:]] = struct $Float (%[[#C11]] : $Builtin.FPIEEE32)
+  // COMBINE-NOT:     function_ref @$vjpSin
+  // CHECK:           %[[#C13:]] = builtin "int_cos_FPIEEE32"(%[[#C10]] : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  // COMBINE-NOT:     function_ref @$vjpCos
+  // COMBINE-NOT:     function_ref @$vjpMultiply
+  // CHECK:           %[[#C14:]] = struct $Float (%[[#C13]] : $Builtin.FPIEEE32)
+  // CHECK:           %[[#C15:]] = function_ref @$s11$pullback_g7$vjpSinSf0B3CosSf0B8MultiplyS2fTf1nccc_n : $@convention(thin) (Float, Float, Float, Float, Float) -> Float
+  // CHECK:           %[[#C16:]] = partial_apply [callee_guaranteed] %[[#C15]](%0, %0, %[[#C14]], %[[#C12]]) : $@convention(thin) (Float, Float, Float, Float, Float) -> Float
+  // CHECK:           %[[#C17:]] = tuple (%[[#]] : $Float, %[[#C16]] : $@callee_guaranteed (Float) -> Float)
+  // CHECK:           return %[[#C17]]
+
+  %2 = struct_extract %0 : $Float, #Float._value
+  %3 = builtin "int_sin_FPIEEE32"(%2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  %4 = struct $Float (%3 : $Builtin.FPIEEE32)
+  // function_ref closure #1 in _vjpSin(_:)
+  %5 = function_ref @$vjpSin : $@convention(thin) (Float, Float) -> Float
+  %6 = partial_apply [callee_guaranteed] %5(%0) : $@convention(thin) (Float, Float) -> Float
+  %7 = builtin "int_cos_FPIEEE32"(%2 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  %8 = struct $Float (%7 : $Builtin.FPIEEE32)
+  // function_ref closure #1 in _vjpCos(_:)
+  %9 = function_ref @$vjpCos : $@convention(thin) (Float, Float) -> Float
+  %10 = partial_apply [callee_guaranteed] %9(%0) : $@convention(thin) (Float, Float) -> Float
+  %11 = builtin "fmul_FPIEEE32"(%3 : $Builtin.FPIEEE32, %7 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  %12 = struct $Float (%11 : $Builtin.FPIEEE32)
+  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
+  %13 = function_ref @$vjpMultiply : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %14 = partial_apply [callee_guaranteed] %13(%8, %4) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // function_ref pullback of g(_:)
+  %15 = function_ref @$pullback_g : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %16 = partial_apply [callee_guaranteed] %15(%6, %10, %14) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> Float, @owned @callee_guaranteed (Float) -> (Float, Float)) -> Float
+  %17 = tuple (%12 : $Float, %16 : $@callee_guaranteed (Float) -> Float)
+  return %17 : $(Float, @callee_guaranteed (Float) -> Float)
+}
+
+///////////////////////////////
+/// Parameter subset thunks ///
+///////////////////////////////
+struct X : Differentiable {
+  @_hasStorage var a: Float { get set }
+  @_hasStorage var b: Double { get set }
+  struct TangentVector : AdditiveArithmetic, Differentiable {
+    @_hasStorage var a: Float { get set }
+    @_hasStorage var b: Double { get set }
+    static func + (lhs: X.TangentVector, rhs: X.TangentVector) -> X.TangentVector
+    static func - (lhs: X.TangentVector, rhs: X.TangentVector) -> X.TangentVector
+    @_implements(Equatable, ==(_:_:)) static func __derived_struct_equals(_ a: X.TangentVector, _ b: X.TangentVector) -> Bool
+    typealias TangentVector = X.TangentVector
+    init(a: Float, b: Double)
+    static var zero: X.TangentVector { get }
+  }
+  init(a: Float, b: Double)
+  mutating func move(by offset: X.TangentVector)
+}
+
+sil [transparent] [thunk] @subset_parameter_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector
+
+sil @pullback_f : $@convention(thin) (Float, Double) -> X.TangentVector
+
+sil shared [ossa] @pullback_g : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) -> X.TangentVector {
+bb0(%0 : $Float, %1 : @owned $@callee_guaranteed (Float) -> X.TangentVector):
+  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> X.TangentVector
+  destroy_value %1 : $@callee_guaranteed (Float) -> X.TangentVector
+  return %2 : $X.TangentVector
+}
+
+sil hidden [ossa] @$s5test21g1xSfAA1XV_tFTJrSpSr : $@convention(thin) (X) -> (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) {
+bb0(%0 : $X):
+  // CHECK:         sil shared [ossa] @$s10pullback_g0A2_fTf1nc_n : $@convention(thin) (Float) -> X.TangentVector {
+  // CHECK:         bb0(%0 : $Float):
+  // CHECK:           %[[#D3:]] = function_ref @subset_parameter_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector
+  // CHECK:           %[[#D1:]] = function_ref @pullback_f : $@convention(thin) (Float, Double) -> X.TangentVector
+  // CHECK:           %[[#D2:]] = thin_to_thick_function %[[#D1]] : $@convention(thin) (Float, Double) -> X.TangentVector to $@callee_guaranteed (Float, Double) -> X.TangentVector
+  // COMBINE:         %[[#D5:]] = apply %[[#D3]](%0, %[[#D2]]) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector
+  // CHECK:           return %[[#D5]]
+
+  // CHECK:         sil hidden [ossa] @$s5test21g1xSfAA1XV_tFTJrSpSr : $@convention(thin) (X) -> (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) {
+  // CHECK:         bb0(%0 : $X):
+  // CHECK:           %[[#D6:]] = struct_extract %0 : $X, #X.a
+  // COMBINE-NOT:     function_ref @pullback_f
+  // COMBINE-NOT:     function_ref @subset_parameter_thunk
+  // CHECK:           %[[#D7:]] = function_ref @$s10pullback_g0A2_fTf1nc_n : $@convention(thin) (Float) -> X.TangentVector
+  // COMBINE:         %[[#D8:]] = thin_to_thick_function %[[#D7]] : $@convention(thin) (Float) -> X.TangentVector to $@callee_guaranteed (Float) -> X.TangentVector
+  // CHECK:           %[[#D9:]] = tuple (%[[#D6]] : $Float, %[[#D8]] : $@callee_guaranteed (Float) -> X.TangentVector)
+  // CHECK:           return %[[#D9]]
+
+  %1 = struct_extract %0 : $X, #X.a
+  // function_ref pullback_f
+  %2 = function_ref @pullback_f : $@convention(thin) (Float, Double) -> X.TangentVector
+  %3 = thin_to_thick_function %2 : $@convention(thin) (Float, Double) -> X.TangentVector to $@callee_guaranteed (Float, Double) -> X.TangentVector
+  // function_ref subset_parameter_thunk
+  %4 = function_ref @subset_parameter_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector
+  %5 = partial_apply [callee_guaranteed] %4(%3) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (Float, Double) -> X.TangentVector) -> X.TangentVector
+  // function_ref pullback_g
+  %6 = function_ref @pullback_g : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) -> X.TangentVector
+  %7 = partial_apply [callee_guaranteed] %6(%5) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> X.TangentVector) -> X.TangentVector
+  %8 = tuple (%1 : $Float, %7 : $@callee_guaranteed (Float) -> X.TangentVector)
+  return %8 : $(Float, @callee_guaranteed (Float) -> X.TangentVector)
+}
+
+///////////////////////////////////////////////////////////////////////
+///////// Specialized generic closures - PartialApply Closure /////////
+///////////////////////////////////////////////////////////////////////
+
+// closure #1 in static Float._vjpMultiply(lhs:rhs:)
+sil @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+
+// thunk for @escaping @callee_guaranteed (@unowned Float) -> (@unowned Float, @unowned Float)
+sil [transparent] [reabstraction_thunk] @$sS3fIegydd_S3fIegnrr_TR : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float)
+
+// function_ref specialized pullback of f<A>(a:)
+sil [transparent] [thunk] @pullback_f_specialized : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float
+
+// thunk for @escaping @callee_guaranteed (@in_guaranteed Float) -> (@out Float)
+sil [transparent] [reabstraction_thunk] @$sS2fIegnr_S2fIegyd_TR : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+
+sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @pullback_h : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float {
+bb0(%0 : $Float, %1 : @owned $@callee_guaranteed (Float) -> Float):
+  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> Float
+  destroy_value %1 : $@callee_guaranteed (Float) -> Float
+  return %2 : $Float
+}
+
+// reverse-mode derivative of h(x:)
+sil hidden [ossa] @$s5test21h1xS2f_tFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+bb0(%0 : $Float):
+  // CHECK:         sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @$s10pullback_h073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbackti1_j5FZSf_J6SfcfU_S2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float {
+  // CHECK:         bb0(%0 : $Float, %1 : $Float, %2 : $Float):
+  // CHECK:           %[[#E8:]] = function_ref @$sS2fIegnr_S2fIegyd_TR : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+  // CHECK:           %[[#E6:]] = function_ref @pullback_f_specialized : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float
+  // CHECK:           %[[#E3:]] = function_ref @$sS3fIegydd_S3fIegnrr_TR : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float)
+  // CHECK:           %[[#E1:]] = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // CHECK:           %[[#E2:]] = partial_apply [callee_guaranteed] %[[#E1]](%1, %2) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  // CHECK:           %[[#E4:]] = partial_apply [callee_guaranteed] %[[#E3]](%[[#E2]]) : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float)
+  // CHECK:           %[[#E5:]] = convert_function %[[#E4]] : $@callee_guaranteed (@in_guaranteed Float) -> (@out Float, @out Float) to $@callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>
+  // CHECK:           %[[#E7:]] = partial_apply [callee_guaranteed] %[[#E6]](%[[#E5]]) : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float
+  // COMBINE:         %[[#E10:]] = apply %[[#E8]](%0, %[[#E7]]) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+  // COMBINE:         destroy_value %[[#E7]] : $@callee_guaranteed (@in_guaranteed Float) -> @out Float
+  // CHECK:           return %[[#E10]]
+
+  // CHECK:         sil hidden [ossa] @$s5test21h1xS2f_tFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK:         bb0(%0 : $Float):
+  // CHECK:           %[[#E11:]] = struct_extract %0 : $Float, #Float._value
+  // CHECK:           %[[#E12:]] = builtin "fmul_FPIEEE32"(%[[#E11]] : $Builtin.FPIEEE32, %1 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+  // COMBINE-NOT:     function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_
+  // COMBINE-NOT:     function_ref @$sS3fIegydd_S3fIegnrr_TR
+  // COMBINE-NOT:     function_ref @pullback_f_specialized
+  // COMBINE-NOT:     function_ref @$sS2fIegnr_S2fIegyd_TR
+  // CHECK:           %[[#E13:]] = struct $Float (%[[#E12]] : $Builtin.FPIEEE32)
+  // CHECK:           %[[#E14:]] = function_ref @$s10pullback_h073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbackti1_j5FZSf_J6SfcfU_S2fTf1nc_n : $@convention(thin) (Float, Float, Float) -> Float
+  // CHECK:           %[[#E15:]] = partial_apply [callee_guaranteed] %[[#E14]](%0, %0) : $@convention(thin) (Float, Float, Float) -> Float
+  // CHECK:           %[[#E16:]] = tuple (%[[#E13]] : $Float, %[[#E15]] : $@callee_guaranteed (Float) -> Float)
+  // CHECK:           return %[[#E16]]
+
+  %1 = struct_extract %0 : $Float, #Float._value
+  %2 = builtin "fmul_FPIEEE32"(%1 : $Builtin.FPIEEE32, %1 : $Builtin.FPIEEE32) : $Builtin.FPIEEE32
+
+  // function_ref closure #1 in static Float._vjpMultiply(lhs:rhs:)
+  %3 = function_ref @$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktSf_SftFZSf_SftSfcfU_ : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+  %4 = partial_apply [callee_guaranteed] %3(%0, %0) : $@convention(thin) (Float, Float, Float) -> (Float, Float)
+
+  // function_ref thunk for @escaping @callee_guaranteed (@unowned Float) -> (@unowned Float, @unowned Float)
+  %5 = function_ref @$sS3fIegydd_S3fIegnrr_TR : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float)
+  %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (@in_guaranteed Float, @guaranteed @callee_guaranteed (Float) -> (Float, Float)) -> (@out Float, @out Float)
+  %7 = convert_function %6 : $@callee_guaranteed (@in_guaranteed Float) -> (@out Float, @out Float) to $@callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>
+
+  // function_ref pullback_f_specialized
+  %8 = function_ref @pullback_f_specialized : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float
+  %9 = partial_apply [callee_guaranteed] %8(%7) : $@convention(thin) (@in_guaranteed Float, @owned @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2> (@in_guaranteed τ_0_0) -> (@out τ_0_1, @out τ_0_2) for <Float, Float, Float>) -> @out Float
+
+  // function_ref thunk for @escaping @callee_guaranteed (@in_guaranteed Float) -> (@out Float)
+  %10 = function_ref @$sS2fIegnr_S2fIegyd_TR : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+  %11 = partial_apply [callee_guaranteed] %10(%9) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+  %12 = struct $Float (%2 : $Builtin.FPIEEE32)
+
+  // function_ref pullback_h
+  %13 = function_ref @pullback_h : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float
+  %14 = partial_apply [callee_guaranteed] %13(%11) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float
+  %15 = tuple (%12 : $Float, %14 : $@callee_guaranteed (Float) -> Float)
+  return %15 : $(Float, @callee_guaranteed (Float) -> Float)
+}
+
+//////////////////////////////////////////////////////////////////////////////
+///////// Specialized generic closures - ThinToThickFunction closure /////////
+//////////////////////////////////////////////////////////////////////////////
+
+sil [transparent] [thunk] @pullback_y_specialized : $@convention(thin) (@in_guaranteed Float) -> @out Float
+
+sil [transparent] [reabstraction_thunk] @reabstraction_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+
+sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @pullback_z : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float {
+bb0(%0 : $Float, %1 : @owned $@callee_guaranteed (Float) -> Float):
+  %2 = apply %1(%0) : $@callee_guaranteed (Float) -> Float
+  destroy_value %1 : $@callee_guaranteed (Float) -> Float
+  return %2 : $Float
+}
+
+sil hidden [ossa] @$s5test21z1xS2f_tFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+bb0(%0 : $Float):
+  // CHECK:         sil private [signature_optimized_thunk] [heuristic_always_inline] [ossa] @$s10pullback_z0A14_y_specializedTf1nc_n : $@convention(thin) (Float) -> Float {
+  // CHECK:         bb0(%0 : $Float):
+  // CHECK:           %[[#F3:]] = function_ref @reabstraction_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+  // CHECK:           %[[#F1:]] = function_ref @pullback_y_specialized : $@convention(thin) (@in_guaranteed Float) -> @out Float
+  // CHECK:           %[[#F2:]] = thin_to_thick_function %[[#F1]] : $@convention(thin) (@in_guaranteed Float) -> @out Float to $@callee_guaranteed (@in_guaranteed Float) -> @out Float
+  // COMBINE:         %[[#F5:]] = apply %[[#F3]](%0, %[[#F2]]) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+  // CHECK:           return %[[#F5]]
+
+  // CHECK:         sil hidden [ossa] @$s5test21z1xS2f_tFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK:         bb0(%0 : $Float):
+  // COMBINE-NOT:   function_ref @pullback_y_specialized
+  // COMBINE-NOT:   function_ref @reabstraction_thunk
+  // CHECK:         %[[#F6:]] = function_ref @$s10pullback_z0A14_y_specializedTf1nc_n : $@convention(thin) (Float) -> Float
+  // COMBINE:       %[[#F7:]] = thin_to_thick_function %[[#F6]] : $@convention(thin) (Float) -> Float to $@callee_guaranteed (Float) -> Float
+  // CHECK:         %[[#F8:]] = tuple (%0 : $Float, %[[#F7]] : $@callee_guaranteed (Float) -> Float)
+  // CHECK:         return %[[#F8]]
+
+  // function_ref pullback_y_specialized
+  %1 = function_ref @pullback_y_specialized : $@convention(thin) (@in_guaranteed Float) -> @out Float
+  %2 = thin_to_thick_function %1 : $@convention(thin) (@in_guaranteed Float) -> @out Float to $@callee_guaranteed (@in_guaranteed Float) -> @out Float
+  // function_ref reabstraction_thunk
+  %3 = function_ref @reabstraction_thunk : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+  %4 = partial_apply [callee_guaranteed] %3(%2) : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@in_guaranteed Float) -> @out Float) -> Float
+  // function_ref pullback_z
+  %5 = function_ref @pullback_z : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float
+  %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (Float, @owned @callee_guaranteed (Float) -> Float) -> Float
+  %7 = tuple (%0 : $Float, %6 : $@callee_guaranteed (Float) -> Float)
+  return %7 : $(Float, @callee_guaranteed (Float) -> Float)
+}
diff --git a/test/AutoDiff/SILOptimizer/differentiation_control_flow_diagnostics.swift b/test/AutoDiff/SILOptimizer/differentiation_control_flow_diagnostics.swift
index a5a8a13ac5252..6c6ba960de7c0 100644
--- a/test/AutoDiff/SILOptimizer/differentiation_control_flow_diagnostics.swift
+++ b/test/AutoDiff/SILOptimizer/differentiation_control_flow_diagnostics.swift
@@ -168,11 +168,11 @@ enum Tree : Differentiable & AdditiveArithmetic {
 // (`Collection.makeIterator` and `IteratorProtocol.next`).
 // expected-error @+1 {{function is not differentiable}}
 @differentiable(reverse)
-// expected-note @+2 {{when differentiating this function definition}}
-// expected-note @+1 {{cannot differentiate through a non-differentiable result; do you want to use 'withoutDerivative(at:)'?}} {{+2:12-12=withoutDerivative(at: }} {{+2:17-17=)}}
 func loop_array(_ array: [Float]) -> Float {
+  // expected-note@-1 {{when differentiating this function definition}}
   var result: Float = 1
   for x in array {
+    // expected-note@-1 {{cannot differentiate through a non-differentiable result; do you want to use 'withoutDerivative(at:)'}}
     result = result * x
   }
   return result
diff --git a/test/AutoDiff/SILOptimizer/differentiation_diagnostics.swift b/test/AutoDiff/SILOptimizer/differentiation_diagnostics.swift
index 34f09959d7680..bc7c3bb71c22b 100644
--- a/test/AutoDiff/SILOptimizer/differentiation_diagnostics.swift
+++ b/test/AutoDiff/SILOptimizer/differentiation_diagnostics.swift
@@ -46,6 +46,17 @@ func try_apply_rethrows(_ x: Float) -> Float {
   return x
 }
 
+// This generates `try_apply` which we do not know to handle yet, therefore
+// one should use a.differentialMap here. If / when differentiation of throwing
+// functions will be supported, we'd need to remove this diagnostics.
+// expected-error @+2 {{function is not differentiable}}
+// expected-note @+2 {{when differentiating this function definition}}
+@differentiable(reverse)
+func map_nondiff(_ a: [Float]) -> [Float] {
+  // expected-note @+1 {{expression is not differentiable}}
+  return a.map { $0 }
+}
+
 //===----------------------------------------------------------------------===//
 // Unreachable
 //===----------------------------------------------------------------------===//
@@ -669,9 +680,7 @@ extension DifferentiableWrapper: Differentiable where Value: Differentiable {}
 // accesses.
 
 struct Struct: Differentiable {
-  // expected-error @+4 {{expression is not differentiable}}
-  // expected-error @+3 {{expression is not differentiable}}
-  // expected-note @+2 {{cannot differentiate access to property 'Struct._x' because 'Struct.TangentVector' does not have a stored property named '_x'}}
+  // expected-error @+2 {{expression is not differentiable}}
   // expected-note @+1 {{cannot differentiate access to property 'Struct._x' because 'Struct.TangentVector' does not have a stored property named '_x'}}  
   @DifferentiableWrapper @DifferentiableWrapper var x: Float = 10
 
diff --git a/test/AutoDiff/SILOptimizer/optional_pullback.swift b/test/AutoDiff/SILOptimizer/optional_pullback.swift
index 0156f442e3c2b..9ff9ebb5912cf 100644
--- a/test/AutoDiff/SILOptimizer/optional_pullback.swift
+++ b/test/AutoDiff/SILOptimizer/optional_pullback.swift
@@ -13,14 +13,9 @@ import _Differentiation
 // CHECK: apply %[[ZERO1]]<τ_0_0.TangentVector>(%[[RET_TAN_BUF]], %{{.*}})
 // CHECK: %[[ADJ_IN_BB:.+]] = alloc_stack $τ_0_0.TangentVector
 //
-// CHECK: %[[TAN_VAL_COPY:.+]] = alloc_stack $Optional<τ_0_0.TangentVector>
-// CHECK: %[[TAN_BUF:.+]] = alloc_stack $Optional<τ_0_0>.TangentVector
-
-// CHECK: copy_addr %[[OPT_TAN]] to [init] %[[TAN_BUF]] : $*Optional<τ_0_0>.TangentVector
-// CHECK: %[[TAN_VAL:.+]] = struct_element_addr %[[TAN_BUF]] : $*Optional<τ_0_0>.TangentVector, #Optional.TangentVector.value
-// CHECK: copy_addr %[[TAN_VAL]] to [init] %[[TAN_VAL_COPY]] : $*Optional<τ_0_0.TangentVector>
+// CHECK: %[[TAN_VAL:.+]] = struct_element_addr %[[OPT_TAN]] : $*Optional<τ_0_0>.TangentVector, #Optional.TangentVector.value
 //
-// CHECK: %[[TAN_DATA:.+]] = unchecked_take_enum_data_addr %[[TAN_VAL_COPY]] : $*Optional<τ_0_0.TangentVector>, #Optional.some!enumelt
+// CHECK: %[[TAN_DATA:.+]] = unchecked_take_enum_data_addr %[[TAN_VAL]] : $*Optional<τ_0_0.TangentVector>, #Optional.some!enumelt
 // CHECK: %[[PLUS_EQUAL:.+]] = witness_method $τ_0_0.TangentVector, #AdditiveArithmetic."+="
 // CHECK: apply %[[PLUS_EQUAL]]<τ_0_0.TangentVector>(%[[ADJ_IN_BB]], %[[TAN_DATA]], %{{.*}})
 
@@ -29,9 +24,6 @@ import _Differentiation
 // CHECK: destroy_addr %[[ADJ_IN_BB]] : $*τ_0_0.TangentVector
 
 // CHECK: copy_addr [take] %[[RET_TAN_BUF:.+]] to [init] %[[RET_TAN:.+]]
-// CHECK: destroy_addr %[[TAN_BUF]] : $*Optional<τ_0_0>.TangentVector
-// CHECK: dealloc_stack %[[TAN_BUF]] : $*Optional<τ_0_0>.TangentVector
-// CHECK: dealloc_stack %[[TAN_VAL_COPY]] : $*Optional<τ_0_0.TangentVector>
 // CHECK: dealloc_stack %[[RET_TAN_BUF]] : $*τ_0_0.TangentVector
 
 @differentiable(reverse)
diff --git a/test/AutoDiff/SILOptimizer/pullback_generation.swift b/test/AutoDiff/SILOptimizer/pullback_generation.swift
index 9f3ea25a65a25..3bb1ab02ba076 100644
--- a/test/AutoDiff/SILOptimizer/pullback_generation.swift
+++ b/test/AutoDiff/SILOptimizer/pullback_generation.swift
@@ -182,22 +182,22 @@ func f4(a: NonTrivial) -> Float {
 }
 
 // CHECK-LABEL: sil private [ossa] @$s19pullback_generation2f41aSfAA10NonTrivialV_tFTJpSpSr : $@convention(thin) (Float, @guaranteed Builtin.NativeObject) -> @owned NonTrivial {
-// CHECK: bb5(%67 : @owned $NonTrivial, %68 : $Float, %69 : @owned $(predecessor: _AD__$s19pullback_generation2f41aSfAA10NonTrivialV_tF_bb2__Pred__src_0_wrt_0, @callee_guaranteed (@inout Float) -> Float)):
-// CHECK: %88 = alloc_stack $NonTrivial
+// CHECK: bb5(%[[#ARG0:]] : @owned $NonTrivial, %[[#]] : $Float, %[[#]] : @owned $(predecessor: _AD__$s19pullback_generation2f41aSfAA10NonTrivialV_tF_bb2__Pred__src_0_wrt_0, @callee_guaranteed (@inout Float) -> Float)):
+// CHECK: %[[#T0:]] = alloc_stack $NonTrivial
 
 // Non-trivial value must be copied or there will be a
 // double consume when all owned parameters are destroyed 
 // at the end of the basic block.
-// CHECK: %89 = copy_value %67 : $NonTrivial              
+// CHECK: %[[#T1:]] = copy_value %[[#ARG0]] : $NonTrivial
 
-// CHECK: store %89 to [init] %88 : $*NonTrivial          
-// CHECK: %91 = struct_element_addr %88 : $*NonTrivial, #NonTrivial.x 
-// CHECK: %92 = alloc_stack $Float                        
-// CHECK: store %86 to [trivial] %92 : $*Float            
-// CHECK: %94 = witness_method $Float, #AdditiveArithmetic."+=" : <Self where Self : AdditiveArithmetic> (Self.Type) -> (inout Self, Self) -> () : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@inout τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> () 
-// CHECK: %95 = metatype $@thick Float.Type               
-// CHECK: %96 = apply %94<Float>(%91, %92, %95) : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@inout τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> ()
-// CHECK: destroy_value %67 : $NonTrivial
+// CHECK: store %[[#T1]] to [init] %[[#T0]] : $*NonTrivial
+// CHECK: %[[#T2:]] = struct_element_addr %[[#T0]] : $*NonTrivial, #NonTrivial.x
+// CHECK: %[[#T3:]] = alloc_stack $Float
+// CHECK: store %[[#T4:]] to [trivial] %[[#T3]] : $*Float
+// CHECK: %[[#T5:]] = witness_method $Float, #AdditiveArithmetic."+=" : <Self where Self : AdditiveArithmetic> (Self.Type) -> (inout Self, Self) -> () : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@inout τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> ()
+// CHECK: %[[#T6:]] = metatype $@thick Float.Type
+// CHECK: %[[#]] = apply %[[#T5]]<Float>(%[[#T2]], %[[#T3]], %[[#T6]]) : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@inout τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> ()
+// CHECK: destroy_value %[[#ARG0]] : $NonTrivial
 
 @differentiable(reverse)
 func move_value(x: Float) -> Float {
@@ -218,5 +218,5 @@ func move_value(x: Float) -> Float {
 // CHECK:         %[[#]] = apply %[[#T2]]<Float>(%[[#T1]], %[[#T3]]) : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@thick τ_0_0.Type) -> @out τ_0_0
 // CHECK:         %[[#T4:]] = load [trivial] %[[#T1]]
 // CHECK:         dealloc_stack %[[#T1]]
-// CHECK:       bb4(%113 : $Builtin.RawPointer):
+// CHECK:       bb4(%[[#]] : $Builtin.RawPointer):
 // CHECK:         br bb5(%[[#]] : $Float, %[[#]] : $Float, %[[#T4]] : $Float, %[[#]] : $(predecessor: _AD__$s19pullback_generation10move_value1xS2f_tF_bb2__Pred__src_0_wrt_0))
diff --git a/test/AutoDiff/SILOptimizer/pullback_generation_loop_adjoints.swift b/test/AutoDiff/SILOptimizer/pullback_generation_loop_adjoints.swift
new file mode 100644
index 0000000000000..c8cc1af2026b9
--- /dev/null
+++ b/test/AutoDiff/SILOptimizer/pullback_generation_loop_adjoints.swift
@@ -0,0 +1,316 @@
+// RUN: %target-swift-frontend -emit-sil -Xllvm --sil-print-after=differentiation %s 2>&1 | %FileCheck %s
+// RUN: %target-swift-frontend -emit-sil -Xllvm --debug-only=differentiation      %s 2>&1 | %FileCheck --check-prefix=DEBUG %s
+
+// Needed for '--debug-only'
+// REQUIRES: asserts
+
+import _Differentiation
+
+@differentiable(reverse)
+func repeat_while_loop(x: Float) -> Float {
+  var result : Float
+  repeat {
+    result = x + 0
+  } while 0 == 1
+  return result
+}
+
+// DEBUG-LABEL: [AD] Running PullbackCloner on
+// DEBUG-NEXT:  // repeat_while_loop
+// DEBUG:       [AD] Begin search for adjoints of loop-local active values
+
+// CHECK-LABEL: // pullback of repeat_while_loop(x:)
+
+// DEBUG-NEXT:  [AD] Original bb1 belongs to a loop, original header bb1, pullback header bb3
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#AARG0:]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#A0:]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#A1:]] = apply %[[#A2:]](%[[#AARG0]], %[[#A3:]], %[[#A4:]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#A1]] = apply %[[#A2]](%[[#AARG0]], %[[#A3]], %[[#A4]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#A5:]] = begin_access [modify] [static] %[[#A0]] : $*Float
+
+// CHECK:       bb3(%[[ARG31:[0-9]+]] : $Float, %[[ARG32:[0-9]+]] : $Float, %[[ARG33:[0-9]+]] : @owned $(predecessor: _AD__$s33pullback_generation_loop_adjoints013repeat_while_C01xS2f_tF_bb1__Pred__src_0_wrt_0, @callee_guaranteed (Float) -> Float)):
+// CHECK:         (%[[T01:[0-9]+]], %[[T02:[0-9]+]]) = destructure_tuple %[[ARG33]]
+// CHECK:         %[[T03:[0-9]+]] = load [trivial] %[[V1:[0-9]+]]
+
+/// Ensure that we do not add adjoint from the previous iteration
+/// The incorrect SIL looked like the following:
+///   %[[T03]] = load [trivial] %[[V1]]
+///   store %[[#B08]] to [trivial] %[[#B13]]                            // <-- we check absence of this
+///   store %[[T03]] to [trivial] %[[#B12]]
+///   %62 = witness_method $Float, #AdditiveArithmetic."+"
+///   %63 = metatype $@thick Float.Type
+///   %64 = apply %62<Float>(%[[#]], %[[#B12]], %[[#B13]], %63)
+// CHECK-NOT:     store %[[ARG32]] to [trivial] %[[#]]
+
+// CHECK:         %[[T04:[0-9]+]] = witness_method $Float, #AdditiveArithmetic.zero!getter : <Self where Self : AdditiveArithmetic> (Self.Type) -> () -> Self : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@thick τ_0_0.Type) -> @out τ_0_0
+// CHECK:         %[[T05:[0-9]+]] = metatype $@thick Float.Type
+// CHECK:         %[[#]] = apply %[[T04]]<Float>(%[[V1]], %[[T05]]) : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@thick τ_0_0.Type) -> @out τ_0_0
+
+/// It's crucial that we call pullback with T03 which does not contain adjoints from previous iterations
+// CHECK:         %[[T07:[0-9]+]] = apply %[[T02]](%[[T03]]) : $@callee_guaranteed (Float) -> Float
+
+// CHECK:         destroy_value %[[T02]]
+// CHECK:         %[[T08:[0-9]+]] = alloc_stack $Float
+// CHECK:         %[[T09:[0-9]+]] = alloc_stack $Float
+// CHECK:         %[[T10:[0-9]+]] = alloc_stack $Float
+// CHECK:         store %[[ARG31]] to [trivial] %[[T09]]
+// CHECK:         store %[[T07]] to [trivial] %[[T10]]
+// CHECK:         %[[T11:[0-9]+]] = witness_method $Float, #AdditiveArithmetic."+" : <Self where Self : AdditiveArithmetic> (Self.Type) -> (Self, Self) -> Self : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
+// CHECK:         %[[T12:[0-9]+]] = metatype $@thick Float.Type
+// CHECK:         %[[#]] = apply %[[T11]]<Float>(%[[T08]], %[[T10]], %[[T09]], %[[T12]]) : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
+// CHECK:         destroy_addr %[[T09]]
+// CHECK:         destroy_addr %[[T10]]
+// CHECK:         dealloc_stack %[[T10]]
+// CHECK:         dealloc_stack %[[T09]]
+// CHECK:         %[[T14:[0-9]+]] = load [trivial] %[[T08]]
+// CHECK:         dealloc_stack %[[T08]]
+// CHECK:         debug_value %[[T14]], let, name "x", argno 1
+// CHECK:         copy_addr %[[V1]] to %[[V2:[0-9]+]]
+// CHECK:         debug_value %[[T14]], let, name "x", argno 1
+// CHECK:         copy_addr %[[V1]] to %[[V3:[0-9]+]]
+// CHECK:         switch_enum %[[T01]], case #_AD__$s33pullback_generation_loop_adjoints013repeat_while_C01xS2f_tF_bb1__Pred__src_0_wrt_0.bb2!enumelt: bb4, case #_AD__$s33pullback_generation_loop_adjoints013repeat_while_C01xS2f_tF_bb1__Pred__src_0_wrt_0.bb0!enumelt: bb6, forwarding: @owned
+
+// CHECK:       bb4(%[[ARG41:[0-9]+]] : $Builtin.RawPointer):
+// CHECK:         %[[T15:[0-9]+]] = pointer_to_address %[[ARG41]] to [strict] $*(predecessor: _AD__$s33pullback_generation_loop_adjoints013repeat_while_C01xS2f_tF_bb2__Pred__src_0_wrt_0)
+// CHECK:         %[[T16:[0-9]+]] = load [trivial] %[[T15]]
+// CHECK:         br bb5(%[[T14]], %[[T03]], %[[T16]])
+
+// DEBUG-NEXT:  [AD] Original bb2 belongs to a loop, original header bb1, pullback header bb3
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#AARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#A0]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#A1]] = apply %[[#A2]](%[[#AARG0]], %[[#A3]], %[[#A4]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#A5]] = begin_access [modify] [static] %[[#A0]] : $*Float
+
+// CHECK:       bb5(%[[ARG51:[0-9]+]] : $Float, %[[ARG52:[0-9]+]] : $Float, %[[ARG53:[0-9]+]] : $(predecessor: _AD__$s33pullback_generation_loop_adjoints013repeat_while_C01xS2f_tF_bb2__Pred__src_0_wrt_0)):
+
+/// Ensure that we do not zero adjoints for non-loop-local active values
+// CHECK-NOT:     witness_method $Float, #AdditiveArithmetic.zero!getter
+
+// CHECK:         %[[T17:[0-9]+]] = destructure_tuple %[[ARG53]]
+// CHECK:         debug_value %[[ARG51]], let, name "x", argno 1
+// CHECK:         copy_addr %[[V2]] to %[[V1]]
+// CHECK:         switch_enum %[[T17]], case #_AD__$s33pullback_generation_loop_adjoints013repeat_while_C01xS2f_tF_bb2__Pred__src_0_wrt_0.bb1!enumelt: bb1, forwarding: @owned
+
+// DEBUG-NEXT:  [AD] End search for adjoints of loop-local active values
+
+@differentiable(reverse)
+func repeat_while_loop_nested(_ x: Float) -> Float {
+  var result = x
+  var i = 0
+  repeat {
+    var temp = x
+    var j = 0
+    repeat {
+      temp = temp * x
+      j += 1
+    } while j < 2
+    result = result * temp
+    i += 1
+  } while i < 2
+  return result
+}
+
+// DEBUG-LABEL: [AD] Running PullbackCloner on
+// DEBUG-NEXT:  // repeat_while_loop_nested
+// DEBUG:       [AD] Begin search for adjoints of loop-local active values
+
+// DEBUG-NEXT:  [AD] Original bb4 belongs to a loop, original header bb1, pullback header bb10
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#BARG0:]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B00:]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is NOT a projection, zeroing its adjoint buffer in loop header:   %[[#B01:]] = alloc_stack [var_decl] $Float, var, name "temp", type $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B02:]] = begin_access [read] [static] %[[#B01]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B03:]] = load [trivial] %[[#B02]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B04:]] = apply %[[#B05:]](%[[#B03]], %[[#BARG0]], %[[#B06:]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B07:]] = begin_access [modify] [static] %[[#B01]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#B08:]] = begin_access [read] [static] %[[#B00]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#B09:]] = load [trivial] %[[#B08]] : $*Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#B09]] = load [trivial] %[[#B08]] : $*Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#B10:]] = begin_access [read] [static] %[[#B01]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#B11:]] = load [trivial] %[[#B10]] : $*Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#B11]] = load [trivial] %[[#B10]] : $*Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#B12:]] = apply %[[#B13:]](%[[#B09]], %[[#B11]], %[[#B14:]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#B12]] = apply %[[#B13]](%[[#B09]], %[[#B11]], %[[#B14]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#B15:]] = begin_access [modify] [static] %[[#B00]] : $*Float
+
+// DEBUG-NEXT:  [AD] Original bb2 belongs to a loop, original header bb2, pullback header bb6
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#BARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B00]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B01]] = alloc_stack [var_decl] $Float, var, name "temp", type $Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#B02]] = begin_access [read] [static] %[[#B01]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#B03]] = load [trivial] %[[#B02]] : $*Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#B03]] = load [trivial] %[[#B02]] : $*Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#B04]] = apply %[[#B05]](%[[#B03]], %[[#BARG0]], %[[#B06]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#B04]] = apply %[[#B05]](%[[#B03]], %[[#BARG0]], %[[#B06]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#B07]] = begin_access [modify] [static] %[[#B01]] : $*Float
+
+// DEBUG-NEXT:  [AD] Original bb3 belongs to a loop, original header bb2, pullback header bb6
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#BARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B00]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B01]] = alloc_stack [var_decl] $Float, var, name "temp", type $Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B02]] = begin_access [read] [static] %[[#B01]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B03]] = load [trivial] %[[#B02]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B04]] = apply %[[#B05]](%[[#B03]], %[[#BARG0]], %[[#B06]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B07]] = begin_access [modify] [static] %[[#B01]] : $*Float
+
+// DEBUG-NEXT:  [AD] Original bb1 belongs to a loop, original header bb1, pullback header bb10
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#BARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B00]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B01]] = alloc_stack [var_decl] $Float, var, name "temp", type $Float
+
+// DEBUG-NEXT:  [AD] Original bb5 belongs to a loop, original header bb1, pullback header bb10
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#BARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B00]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B01]] = alloc_stack [var_decl] $Float, var, name "temp", type $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B02]] = begin_access [read] [static] %[[#B01]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B03]] = load [trivial] %[[#B02]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B04]] = apply %[[#B05]](%[[#B03]], %[[#BARG0]], %[[#B06]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#B07]] = begin_access [modify] [static] %[[#B01]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B08]] = begin_access [read] [static] %[[#B00]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B09]] = load [trivial] %[[#B08]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B10]] = begin_access [read] [static] %[[#B01]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B11]] = load [trivial] %[[#B10]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B12]] = apply %[[#B13]](%[[#B09]], %[[#B11]], %[[#B14]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, but it was already processed, skipping:   %[[#B15]] = begin_access [modify] [static] %[[#B00]] : $*Float
+
+// DEBUG-NEXT:  [AD] End search for adjoints of loop-local active values
+
+@differentiable(reverse)
+func repeat_while_loop_condition(_ x: Float) -> Float {
+  var result = x
+  var i = 0
+  repeat {
+    if i == 2 {
+      break
+    }
+    if i == 0 {
+      result = result * x
+    } else {
+      result = result * result
+    }
+    i += 1
+  } while i < 10
+  return result
+}
+
+// DEBUG-LABEL: [AD] Running PullbackCloner on
+// DEBUG-NEXT:  // repeat_while_loop_condition
+// DEBUG:       [AD] Begin search for adjoints of loop-local active values
+
+// DEBUG-NEXT:  [AD] Original bb6 belongs to a loop, original header bb1, pullback header bb10
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#CARG0:]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#C00:]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+
+// DEBUG-NEXT:  [AD] Original bb1 belongs to a loop, original header bb1, pullback header bb10
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#CARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#C00]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+
+// DEBUG-NEXT:  [AD] Original bb5 belongs to a loop, original header bb1, pullback header bb10
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#CARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#C00]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#C01:]] = begin_access [read] [static] %[[#C00]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#C02:]] = load [trivial] %[[#C01]] : $*Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#C02]] = load [trivial] %[[#C01]] : $*Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#C03:]] = begin_access [read] [static] %[[#C00]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#C04:]] = load [trivial] %[[#C03]] : $*Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#C04]] = load [trivial] %[[#C03]] : $*Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#C05:]] = apply %[[#C06:]](%[[#C02]], %[[#C04]], %[[#C07:]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#C05]] = apply %[[#C06]](%[[#C02]], %[[#C04]], %[[#C07]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#]] = begin_access [modify] [static] %[[#C00]] : $*Float
+
+// DEBUG-NEXT:  [AD] Original bb4 belongs to a loop, original header bb1, pullback header bb10
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#CARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#C00]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#C08:]] = begin_access [read] [static] %[[#C00]] : $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#C09:]] = load [trivial] %[[#C08]] : $*Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#C09]] = load [trivial] %[[#C08]] : $*Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#C10:]] = apply %[[#C11:]](%[[#C09]], %[[#CARG0]], %[[#C12:]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#C10]] = apply %[[#C11]](%[[#C09]], %[[#CARG0]], %[[#C12]]) : $@convention(method) (Float, Float, @thin Float.Type) -> Float
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Float]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#]] = begin_access [modify] [static] %[[#C00]] : $*Float
+
+// DEBUG-NEXT:  [AD] Original bb7 belongs to a loop, original header bb1, pullback header bb10
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#CARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#C00]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+
+// DEBUG-NEXT:  [AD] Original bb3 belongs to a loop, original header bb1, pullback header bb10
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#CARG0]] = argument of bb0 : $Float
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#C00]] = alloc_stack [var_decl] $Float, var, name "result", type $Float
+
+// DEBUG-NEXT:  [AD] End search for adjoints of loop-local active values
+
+typealias FloatArrayTan = Array<Float>.TangentVector
+
+func identity(_ array: [Float]) -> [Float] {
+  var results: [Float] = []
+  for i in withoutDerivative(at: array.indices) {
+    results += [array[i]]
+  }
+  return results
+}
+
+pullback(at: [1, 2, 3], of: identity)(FloatArrayTan([4, -5, 6]))
+
+// DEBUG-LABEL: [AD] Running PullbackCloner on
+// DEBUG-NEXT:  // identity
+// DEBUG:       [AD] Begin search for adjoints of loop-local active values
+
+// DEBUG-NEXT:  [AD] Original bb1 belongs to a loop, original header bb1, pullback header bb3
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#DARG0:]] = argument of bb0 : $Array<Float>
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#D0:]] = alloc_stack [var_decl] $Array<Float>, var, name "results", type $Array<Float>
+
+// DEBUG-NEXT:  [AD] Original bb2 belongs to a loop, original header bb1, pullback header bb3
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping: %[[#DARG0:]] = argument of bb0 : $Array<Float>
+// DEBUG-NEXT:  [AD] The following active value is NOT loop-local, skipping:   %[[#D0]] = alloc_stack [var_decl] $Array<Float>, var, name "results", type $Array<Float>
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#D1:]] = apply %[[#]]<Float>(%[[#]]) : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#D:]] = apply %[[#]]<Float>(%[[#]]) : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Array<Float>.DifferentiableView]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header: (**%[[#D2:]]**, %[[#D3:]]) = destructure_tuple %[[#D1]] : $(Array<Float>, Builtin.RawPointer)
+// DEBUG-NEXT:  [AD] Setting adjoint value for (**%[[#D2]]**, %[[#D3]]) = destructure_tuple %[[#D1]] : $(Array<Float>, Builtin.RawPointer)
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Array<Float>.DifferentiableView]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Materializing adjoint for Zero[$Array<Float>.DifferentiableView]
+// DEBUG-NEXT:  [AD] Recorded temporary   %[[#]] = load [take] %[[#]] : $*Array<Float>.DifferentiableView
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#D4:]] = pointer_to_address %[[#D5:]] : $Builtin.RawPointer to [strict] $*Float
+// DEBUG-NEXT:  [AD] The following active value is loop-local, zeroing its adjoint value in loop header:   %[[#D6:]] = apply %[[#]]<Float>(%[[#D2]]) : $@convention(thin) <τ_0_0> (@owned Array<τ_0_0>) -> @owned Array<τ_0_0>
+// DEBUG-NEXT:  [AD] Setting adjoint value for   %[[#D6]] = apply %[[#]]<Float>(%[[#D2]]) : $@convention(thin) <τ_0_0> (@owned Array<τ_0_0>) -> @owned Array<τ_0_0>
+// DEBUG-NEXT:  [AD] No debug variable found.
+// DEBUG-NEXT:  [AD] The new adjoint value, replacing the existing one, is: Zero[$Array<Float>.DifferentiableView]
+// DEBUG-NEXT:  [AD] The following active value is loop-local, checking if it's adjoint is a projection
+// DEBUG-NEXT:  [AD] Adjoint for the following value is a projection, skipping:   %[[#]] = begin_access [modify] [static] %[[#D0]] : $*Array<Float>
+
+// DEBUG-NEXT:  [AD] End search for adjoints of loop-local active values
diff --git a/test/AutoDiff/SILOptimizer/vjp_inlining.swift b/test/AutoDiff/SILOptimizer/vjp_inlining.swift
index 9f839a6c3afa2..6cc8aa75644f2 100644
--- a/test/AutoDiff/SILOptimizer/vjp_inlining.swift
+++ b/test/AutoDiff/SILOptimizer/vjp_inlining.swift
@@ -9,6 +9,8 @@
 import _Differentiation
 #if canImport(Glibc)
 import Glibc
+#elseif canImport(Android)
+import Android
 #else
 import Foundation
 #endif
diff --git a/test/AutoDiff/Sema/DerivativeRegistrationCrossModule/main.swift b/test/AutoDiff/Sema/DerivativeRegistrationCrossModule/main.swift
index d58879a8292af..068879ba43086 100644
--- a/test/AutoDiff/Sema/DerivativeRegistrationCrossModule/main.swift
+++ b/test/AutoDiff/Sema/DerivativeRegistrationCrossModule/main.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend -emit-module -primary-file %S/Inputs/a.swift -emit-module-path %t/a.swiftmodule
 // RUN: %target-swift-frontend -emit-module -primary-file %S/Inputs/b.swift -emit-module-path %t/b.swiftmodule -I %t
 // "-verify-ignore-unknown" is for "<unknown>:0: note: 'init()' declared here"
-// RUN: %target-swift-frontend-typecheck -verify -verify-ignore-unknown -I %t %s
+// RUN: %target-swift-frontend-typecheck -verify -verify-ignore-unrelated -verify-ignore-unknown -I %t %s
 
 // https://github.com/apple/swift/issues/54969
 // Fix cross-module deserialization crash involving `@derivative` attribute.
diff --git a/test/AutoDiff/Sema/DerivedConformances/class_differentiable.swift b/test/AutoDiff/Sema/DerivedConformances/class_differentiable.swift
index 11c65fb6e22b8..c524050345e71 100644
--- a/test/AutoDiff/Sema/DerivedConformances/class_differentiable.swift
+++ b/test/AutoDiff/Sema/DerivedConformances/class_differentiable.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -primary-file %s %S/Inputs/class_differentiable_other_module.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -primary-file %s %S/Inputs/class_differentiable_other_module.swift
 
 import _Differentiation
 
diff --git a/test/AutoDiff/Sema/DerivedConformances/struct_differentiable.swift b/test/AutoDiff/Sema/DerivedConformances/struct_differentiable.swift
index 0dbb0c16ef610..c5b27df87a278 100644
--- a/test/AutoDiff/Sema/DerivedConformances/struct_differentiable.swift
+++ b/test/AutoDiff/Sema/DerivedConformances/struct_differentiable.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -primary-file %s %S/Inputs/struct_differentiable_other_module.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -primary-file %s %S/Inputs/struct_differentiable_other_module.swift
 
 import _Differentiation
 
diff --git a/test/AutoDiff/Sema/derivative_attr_type_checking.swift b/test/AutoDiff/Sema/derivative_attr_type_checking.swift
index 9740ab1fc589c..89508ff0cec1f 100644
--- a/test/AutoDiff/Sema/derivative_attr_type_checking.swift
+++ b/test/AutoDiff/Sema/derivative_attr_type_checking.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend-typecheck -verify -target %target-swift-5.1-abi-triple %s -package-name myPkg
-// RUN: %target-swift-frontend-typecheck -enable-testing -verify -target %target-swift-5.1-abi-triple %s -package-name myPkg
+// RUN: %target-swift-frontend-typecheck -verify -verify-ignore-unrelated -target %target-swift-5.1-abi-triple %s -package-name myPkg
+// RUN: %target-swift-frontend-typecheck -enable-testing -verify -verify-ignore-unrelated -target %target-swift-5.1-abi-triple %s -package-name myPkg
 
 // Swift.AdditiveArithmetic:3:17: note: cannot yet register derivative default implementation for protocol requirements
 
@@ -1062,6 +1062,15 @@ func _internal_original_inlinable_derivative(_ x: Float) -> (value: Float, pullb
   fatalError()
 }
 
+func internal_original_alwaysemitintoclient_derivative_error(_ x: Float) -> Float { x }
+@_alwaysEmitIntoClient
+@derivative(of: internal_original_alwaysemitintoclient_derivative_error)
+// expected-error @+1 {{either both or none of derivative and original function must have @alwaysEmitIntoClient attribute}}
+func _internal_original_alwaysemitintoclient_derivative_error(_ x: Float) -> (value: Float, pullback: (Float) -> Float) {
+  fatalError()
+}
+
+@_alwaysEmitIntoClient
 func internal_original_alwaysemitintoclient_derivative(_ x: Float) -> Float { x }
 @_alwaysEmitIntoClient
 @derivative(of: internal_original_alwaysemitintoclient_derivative)
@@ -1084,6 +1093,15 @@ package func _package_original_inlinable_derivative(_ x: Float) -> (value: Float
   fatalError()
 }
 
+@_alwaysEmitIntoClient
+package func package_original_alwaysemitintoclient_derivative_error(_ x: Float) -> Float { x }
+@derivative(of: package_original_alwaysemitintoclient_derivative_error)
+// expected-error @+1 {{either both or none of derivative and original function must have @alwaysEmitIntoClient attribute}}
+package func _package_original_alwaysemitintoclient_derivative_error(_ x: Float) -> (value: Float, pullback: (Float) -> Float) {
+  fatalError()
+}
+
+@_alwaysEmitIntoClient
 package func package_original_alwaysemitintoclient_derivative(_ x: Float) -> Float { x }
 @_alwaysEmitIntoClient
 @derivative(of: package_original_alwaysemitintoclient_derivative)
diff --git a/test/AutoDiff/Sema/differentiable_attr_type_checking.swift b/test/AutoDiff/Sema/differentiable_attr_type_checking.swift
index 98ff06879396e..c70c3bad6d8ad 100644
--- a/test/AutoDiff/Sema/differentiable_attr_type_checking.swift
+++ b/test/AutoDiff/Sema/differentiable_attr_type_checking.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend-typecheck -verify -target %target-swift-5.1-abi-triple %s
-// RUN: %target-swift-frontend-typecheck -enable-testing -verify -target %target-swift-5.1-abi-triple %s
+// RUN: %target-swift-frontend-typecheck -verify -verify-ignore-unrelated -target %target-swift-5.1-abi-triple %s
+// RUN: %target-swift-frontend-typecheck -enable-testing -verify -verify-ignore-unrelated -target %target-swift-5.1-abi-triple %s
 
 import _Differentiation
 
diff --git a/test/AutoDiff/Sema/differentiable_features_disabled.swift b/test/AutoDiff/Sema/differentiable_features_disabled.swift
index 0d9f0b26bd9fb..0a6a90bacb766 100644
--- a/test/AutoDiff/Sema/differentiable_features_disabled.swift
+++ b/test/AutoDiff/Sema/differentiable_features_disabled.swift
@@ -1,16 +1,16 @@
 // RUN: %target-swift-frontend -typecheck -verify %s
 
-// expected-error @+1 {{'@differentiable' attribute used without importing module '_Differentiation'}}
+// expected-error @+1 {{'@differentiable' used without importing module '_Differentiation'}}
 let _: @differentiable(reverse) (Float) -> Float
 
-// expected-error @+2 {{'@differentiable' attribute used without importing module '_Differentiation'}}
-// expected-error @+1 {{'@noDerivative' attribute used without importing module '_Differentiation'}}
+// expected-error @+2 {{'@differentiable' used without importing module '_Differentiation'}}
+// expected-error @+1 {{'@noDerivative' used without importing module '_Differentiation'}}
 let _: @differentiable(reverse) (Float, @noDerivative Float) -> Float
 
-// expected-error @+1 {{'@noDerivative' attribute used without importing module '_Differentiation'}}
+// expected-error @+1 {{'@noDerivative' used without importing module '_Differentiation'}}
 let _: (Float, @noDerivative Float) -> Float
 
-// expected-error @+1 {{'@noDerivative' attribute used without importing module '_Differentiation'}}
+// expected-error @+1 {{'@noDerivative' used without importing module '_Differentiation'}}
 let _: @noDerivative Float
 
 func id(_ x: Float) -> Float {
diff --git a/test/AutoDiff/Sema/differentiable_func_type.swift b/test/AutoDiff/Sema/differentiable_func_type.swift
index 2bc467bac7dfd..e83c74fd0a0c6 100644
--- a/test/AutoDiff/Sema/differentiable_func_type.swift
+++ b/test/AutoDiff/Sema/differentiable_func_type.swift
@@ -6,7 +6,7 @@ import _Differentiation
 // Basic @differentiable(reverse) function types.
 //===----------------------------------------------------------------------===//
 
-// expected-error @+1 {{@differentiable attribute only applies to function types}}
+// expected-error @+1 {{'@differentiable' only applies to function types}}
 let _: @differentiable(reverse) Float
 
 let _: @differentiable(reverse) (Float) -> Float
diff --git a/test/AutoDiff/Sema/missing_differentiable_protocol.swift b/test/AutoDiff/Sema/missing_differentiable_protocol.swift
index 747e443cc0dbd..6ef23bb79a55f 100644
--- a/test/AutoDiff/Sema/missing_differentiable_protocol.swift
+++ b/test/AutoDiff/Sema/missing_differentiable_protocol.swift
@@ -2,8 +2,8 @@
 
 // Tests that Sema fails gracefully when the `_Differentiation` module is not imported.
 
-// expected-error @+1 {{'@differentiable' attribute used without importing module '_Differentiation'}}
+// expected-error @+1 {{'@differentiable' used without importing module '_Differentiation'}}
 let _: @differentiable(reverse) (Float) -> Float
 
-// expected-error @+1 2 {{'@differentiable' attribute used without importing module '_Differentiation'}}
+// expected-error @+1 2 {{'@differentiable' used without importing module '_Differentiation'}}
 func hasDifferentiableFunctionArg<T>(_ f: @differentiable(reverse) (T) -> T) {}
diff --git a/test/AutoDiff/Serialization/derivative_attr.swift b/test/AutoDiff/Serialization/derivative_attr.swift
index c41c0a36d1a50..2063f0283423e 100644
--- a/test/AutoDiff/Serialization/derivative_attr.swift
+++ b/test/AutoDiff/Serialization/derivative_attr.swift
@@ -141,7 +141,7 @@ extension S {
     self
   }
 
-  // CHECK: @derivative(of: subscript, wrt: self)
+  // CHECK: @derivative(of: subscript(_:), wrt: self)
   @derivative(of: subscript(_:), wrt: self)
   func derivativeSubscript<T: Differentiable>(x: T) -> (value: S, differential: (S) -> S) {
     (self, { $0 })
diff --git a/test/AutoDiff/Serialization/transpose_attr.swift b/test/AutoDiff/Serialization/transpose_attr.swift
index 9f864862cda95..d969da11c3b8c 100644
--- a/test/AutoDiff/Serialization/transpose_attr.swift
+++ b/test/AutoDiff/Serialization/transpose_attr.swift
@@ -89,7 +89,7 @@ extension S {
 extension S {
   subscript<T: Differentiable>(x: T) -> Self { self }
 
-  // CHECK: @transpose(of: subscript, wrt: self)
+  // CHECK: @transpose(of: subscript(_:), wrt: self)
   @transpose(of: subscript(_:), wrt: self)
   static func transposeSubscript<T: Differentiable>(x: T, t: Self) -> Self {
     t
diff --git a/test/AutoDiff/compiler_crashers_fixed/issue-56600-symbol-in-ir-file-not-tbd-file.swift b/test/AutoDiff/compiler_crashers_fixed/issue-56600-symbol-in-ir-file-not-tbd-file.swift
index 7a5e395dd6551..66b4258c603e8 100644
--- a/test/AutoDiff/compiler_crashers_fixed/issue-56600-symbol-in-ir-file-not-tbd-file.swift
+++ b/test/AutoDiff/compiler_crashers_fixed/issue-56600-symbol-in-ir-file-not-tbd-file.swift
@@ -1,6 +1,8 @@
 // RUN: %target-run-simple-swift
 
 // REQUIRES: executable_test
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
 
 // https://github.com/apple/swift/issues/56600
 // Error: symbol 'powTJfSSpSr' (powTJfSSpSr) is in generated IR file, but not
diff --git a/test/AutoDiff/compiler_crashers_fixed/issue-62608-conflicting-debug-info.swift b/test/AutoDiff/compiler_crashers_fixed/issue-62608-conflicting-debug-info.swift
index c7bb979f54deb..f5f3941d5abe5 100644
--- a/test/AutoDiff/compiler_crashers_fixed/issue-62608-conflicting-debug-info.swift
+++ b/test/AutoDiff/compiler_crashers_fixed/issue-62608-conflicting-debug-info.swift
@@ -38,7 +38,7 @@ public func pullback<T>(
 
 // CHECK-LABEL: sil private @$s4main19testUpdateByCallingyyKF8fOfArrayL_5arraySdSaySdG_tFySdzcfU_TJpSUpSr :
 // CHECK: alloc_stack $Double, var, name "derivative of 'element' in scope at {{.*}} (scope #3)"
-// CHECK: debug_value %{{.*}} : $Builtin.FPIEEE64, var, (name "derivative of 'element' in scope at {{.*}} (scope #1)"
+// CHECK: debug_value %{{.*}} : $Builtin.FPIEEE64, var, (name "derivative of 'element' in scope at {{.*}} (scope #{{.*}})"
 
 public extension Array where Element: Differentiable {
     @inlinable
diff --git a/test/AutoDiff/compiler_crashers_fixed/issue-81607-array-literal-adjoint.swift b/test/AutoDiff/compiler_crashers_fixed/issue-81607-array-literal-adjoint.swift
new file mode 100644
index 0000000000000..73e1ca3ee4de2
--- /dev/null
+++ b/test/AutoDiff/compiler_crashers_fixed/issue-81607-array-literal-adjoint.swift
@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend -emit-sil -verify %s
+
+// https://github.com/swiftlang/swift/issues/81607
+// Ensure we're propagating array adjoint in the correct BB
+
+import _Differentiation
+
+@differentiable(reverse)
+func sum(_ a: Float, _ b: [Float]) -> [Float] {
+  if b.count != 0 {
+    return b
+  }
+  return [a]
+}
diff --git a/test/AutoDiff/compiler_crashers_fixed/issue-84365-autodiff-subset-thunks-differential.swift b/test/AutoDiff/compiler_crashers_fixed/issue-84365-autodiff-subset-thunks-differential.swift
new file mode 100644
index 0000000000000..ac88998f13625
--- /dev/null
+++ b/test/AutoDiff/compiler_crashers_fixed/issue-84365-autodiff-subset-thunks-differential.swift
@@ -0,0 +1,49 @@
+// RUN: %target-swift-frontend -emit-sil -verify %s
+
+// https://github.com/swiftlang/swift/issues/84365
+// Ensure autodiff subset thunks for differential correctly
+// handle multiple semantic results and release unwanted
+// result values
+
+import _Differentiation
+
+@differentiable(reverse,wrt: logits)
+public func softSolveForwardWithQ(logits: [Float]) -> ([Float], [Float]) {
+    return ([Float](repeating: 0, count: 0), [])
+}
+
+@derivative(of: softSolveForwardWithQ, wrt: logits)
+public func vjpSoftSolveForwardWithQ(logits: [Float]) -> (value: ([Float], [Float]), pullback: ([Float].TangentVector, [Float].TangentVector) -> [Float].TangentVector) {
+    let n = logits.count
+    let q = [Float](repeating: 0, count: 0)
+    let y = [Float](repeating: 0, count: 0)
+
+    return (
+        value: (y, q),
+        pullback: { _, _ in 
+            return Array<Float>.DifferentiableView([Float](repeating: 0, count: n))
+        }
+    )
+}
+
+@differentiable(reverse,wrt: logits)
+public func forwardPredict(logits: [Float]) -> ([Float], [Float], [Float]) {
+    let (y, q) = softSolveForwardWithQ(logits: logits)
+    return (y, q, [0.0])
+}
+
+@derivative(of: forwardPredict, wrt: logits)
+public func vjpForwardPredict(logits: [Float]) -> (
+    value: ([Float], [Float], [Float]),
+    pullback: ([Float].TangentVector, [Float].TangentVector, [Float].TangentVector) -> [Float].TangentVector
+) {
+    let (valYQ, pb) = vjpSoftSolveForwardWithQ(logits: logits)
+    let (y, q) = valYQ
+    return ((y, q, [0.0]), { upY, upQ, _ in pb(upY, upQ) }) 
+}
+
+@differentiable(reverse,wrt: logits)
+public func crossEntropyFromForwardPredict(logits: [Float]) -> Float {
+    let (_, q, _) = forwardPredict(logits: logits)
+    return q[0] + 1e-8
+}
diff --git a/test/AutoDiff/stdlib/array_differentiation.swift b/test/AutoDiff/stdlib/array_differentiation.swift
new file mode 100644
index 0000000000000..5d12d60a74547
--- /dev/null
+++ b/test/AutoDiff/stdlib/array_differentiation.swift
@@ -0,0 +1,37 @@
+// RUN: %target-run-simple-swift
+// REQUIRES: executable_test
+
+import _Differentiation
+import StdlibUnittest
+
+var ArrayDifferentiationTests = TestSuite("ArrayDifferentiation")
+
+ArrayDifferentiationTests.test("Array.DifferentiableView+") {
+  let zero1: Array<Float>.DifferentiableView = [0, 0, 0]
+  let zero2: Array<Float>.DifferentiableView = .zero
+  let a: Array<Float>.DifferentiableView = [1, 2, 3]
+  
+  expectEqual(a + a, [2, 4, 6])
+  
+  expectEqual(a + zero1, [1, 2, 3])
+  expectEqual(zero1 + a, [1, 2, 3])
+  
+  expectEqual(a + zero2, [1, 2, 3])
+  expectEqual(zero2 + a, [1, 2, 3])
+}
+
+ArrayDifferentiationTests.test("Array.DifferentiableView-") {
+  let zero1: Array<Float>.DifferentiableView = [0, 0, 0]
+  let zero2: Array<Float>.DifferentiableView = .zero
+  let a: Array<Float>.DifferentiableView = [1, 2, 3]
+  
+  expectEqual(a - a, [0, 0, 0])
+  
+  expectEqual(a - zero1, [1, 2, 3])
+  expectEqual(zero1 - a, [-1, -2, -3])
+  
+  expectEqual(a - zero2, [1, 2, 3])
+  expectEqual(zero2 - a, [-1, -2, -3])
+}
+
+runAllTests()
diff --git a/test/AutoDiff/stdlib/simd.swift b/test/AutoDiff/stdlib/simd.swift
index 04dc27e078c38..32046fa3a2072 100644
--- a/test/AutoDiff/stdlib/simd.swift
+++ b/test/AutoDiff/stdlib/simd.swift
@@ -19,9 +19,6 @@ SIMDTests.test("init(repeating:)") {
   expectEqual(8, pb1(g))
 }
 
-// FIXME(TF-1103): Derivative registration does not yet support
-// `@_alwaysEmitIntoClient` original functions.
-/*
 SIMDTests.test("Sum") {
   let a = SIMD4<Float>(1, 2, 3, 4)
 
@@ -32,7 +29,6 @@ SIMDTests.test("Sum") {
   expectEqual(10, val1)
   expectEqual(SIMD4<Float>(3, 3, 3, 3), pb1(3))
 }
-*/
 
 SIMDTests.test("Identity") {
   let a = SIMD4<Float>(1, 2, 3, 4)
@@ -289,9 +285,6 @@ SIMDTests.test("Generics") {
   expectEqual(SIMD3<Double>(5, 10, 15), val4)
   expectEqual((SIMD3<Double>(5, 5, 5), 6), pb4(g))
 
-  // FIXME(TF-1103): Derivative registration does not yet support
-  // `@_alwaysEmitIntoClient` original functions like `SIMD.sum()`.
-  /*
   func testSum<Scalar, SIMDType: SIMD>(x: SIMDType) -> Scalar
     where SIMDType.Scalar == Scalar,
           SIMDType : Differentiable,
@@ -304,7 +297,6 @@ SIMDTests.test("Generics") {
   let (val5, pb5) = valueWithPullback(at: a, of: simd3Sum)
   expectEqual(6, val5)
   expectEqual(SIMD3<Double>(7, 7, 7), pb5(7))
-  */
 }
 
 runAllTests()
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiFileModule/file1.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiFileModule/file1.swift
new file mode 100644
index 0000000000000..c808c0ef666ed
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiFileModule/file1.swift
@@ -0,0 +1,4 @@
+@_alwaysEmitIntoClient
+public func f(_ x: Float) -> Float {
+  x
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiFileModule/file2.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiFileModule/file2.swift
new file mode 100644
index 0000000000000..1e047d39bdf82
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiFileModule/file2.swift
@@ -0,0 +1,7 @@
+import _Differentiation
+
+@derivative(of: f)
+@_alwaysEmitIntoClient
+public func df(_ x: Float) -> (value: Float, pullback: (Float) -> Float) {
+  (x, { 42 * $0 })
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModule/file1.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModule/file1.swift
new file mode 100644
index 0000000000000..c808c0ef666ed
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModule/file1.swift
@@ -0,0 +1,4 @@
+@_alwaysEmitIntoClient
+public func f(_ x: Float) -> Float {
+  x
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModule/file2.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModule/file2.swift
new file mode 100644
index 0000000000000..8feda0e57f92c
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModule/file2.swift
@@ -0,0 +1,8 @@
+import MultiModule1
+import _Differentiation
+
+@derivative(of: f)
+@_alwaysEmitIntoClient
+public func df(_ x: Float) -> (value: Float, pullback: (Float) -> Float) {
+  (x, { 42 * $0 })
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleProtocol/file1.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleProtocol/file1.swift
new file mode 100644
index 0000000000000..066e1bd2eeed1
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleProtocol/file1.swift
@@ -0,0 +1,16 @@
+import _Differentiation
+
+public protocol Protocol {
+  var x : Float {get set}
+  init()
+}
+
+extension Protocol {
+  public init(_ val: Float) {
+    self.init()
+    x = val
+  }
+
+  @_alwaysEmitIntoClient
+  public func sum() -> Float { x }
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleProtocol/file2.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleProtocol/file2.swift
new file mode 100644
index 0000000000000..e559da2345baa
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleProtocol/file2.swift
@@ -0,0 +1,20 @@
+import MultiModuleProtocol1
+import _Differentiation
+
+extension Protocol where Self: Differentiable, Self.TangentVector == Self {
+  @_alwaysEmitIntoClient
+  @derivative(of: sum)
+  public func _vjpSum() -> (
+    value: Float, pullback: (Float) -> Self.TangentVector
+  ) {
+    (value: self.x, pullback: { Self.TangentVector(42 * $0) })
+  }
+
+  @_alwaysEmitIntoClient
+  @derivative(of: sum)
+  public func _jvpSum() -> (
+    value: Float, differential: (Self.TangentVector) -> Float
+  ) {
+    (value: self.x, differential: { 42 * $0.x })
+  }
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleProtocol/file3.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleProtocol/file3.swift
new file mode 100644
index 0000000000000..4da6021fa69d0
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleProtocol/file3.swift
@@ -0,0 +1,24 @@
+import MultiModuleProtocol1
+import MultiModuleProtocol2
+import _Differentiation
+
+public struct Struct : Protocol {
+  private var _x : Float
+  public  var x : Float {
+    get { _x }
+    set { _x = newValue }
+  }
+  public init() { _x = 0 }
+}
+
+extension Struct : AdditiveArithmetic {
+  public static func +(lhs: Self, rhs: Self) -> Self { Self(lhs.x + rhs.x) }
+  public static func -(lhs: Self, rhs: Self) -> Self { Self(lhs.x - rhs.x) }
+  public static func +=(a: inout Self, b: Self) { a.x = a.x + b.x }
+  public static func -=(a: inout Self, b: Self) { a.x = a.x - b.x }
+  public static var zero: Self { Self(0) }
+}
+
+extension Struct : Differentiable {
+  public  typealias TangentVector = Self
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file1.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file1.swift
new file mode 100644
index 0000000000000..5f4fa36bebf53
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file1.swift
@@ -0,0 +1,23 @@
+public struct Struct {
+  public var x : Float
+  public typealias TangentVector = Self
+  public init() { x = 0 }
+}
+
+extension Struct {
+  public init(_ val: Float) {
+    self.init()
+    x = val
+  }
+
+  @_alwaysEmitIntoClient
+  public func sum() -> Float { x }
+}
+
+extension Struct : AdditiveArithmetic {
+  public static func +(lhs: Self, rhs: Self) -> Self { Self(lhs.x + rhs.x) }
+  public static func -(lhs: Self, rhs: Self) -> Self { Self(lhs.x - rhs.x) }
+  public static func +=(a: inout Self, b: Self) { a.x = a.x + b.x }
+  public static func -=(a: inout Self, b: Self) { a.x = a.x - b.x }
+  public static var zero: Self { Self(0) }
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file2.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file2.swift
new file mode 100644
index 0000000000000..05a63c26de0bc
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file2.swift
@@ -0,0 +1,20 @@
+import MultiModuleStruct1
+import _Differentiation
+
+extension Struct : Differentiable {
+  @_alwaysEmitIntoClient
+  @derivative(of: sum)
+  public func _vjpSum() -> (
+    value: Float, pullback: (Float) -> Self.TangentVector
+  ) {
+    (value: self.x, pullback: { Self.TangentVector(42 * $0) })
+  }
+
+  @_alwaysEmitIntoClient
+  @derivative(of: sum)
+  public func _jvpSum() -> (
+    value: Float, differential: (Self.TangentVector) -> Float
+  ) {
+    (value: self.x, differential: { 42 * $0.x })
+  }
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file2_no_jvp.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file2_no_jvp.swift
new file mode 100644
index 0000000000000..d45a36a13752a
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file2_no_jvp.swift
@@ -0,0 +1,12 @@
+import MultiModuleStruct1
+import _Differentiation
+
+extension Struct : Differentiable {
+  @_alwaysEmitIntoClient
+  @derivative(of: sum)
+  public func _vjpSum() -> (
+    value: Float, pullback: (Float) -> Self.TangentVector
+  ) {
+    (value: self.x, pullback: { Self.TangentVector(42 * $0) })
+  }
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file2_no_vjp.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file2_no_vjp.swift
new file mode 100644
index 0000000000000..7aaf91d5e607a
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/MultiModuleStruct/file2_no_vjp.swift
@@ -0,0 +1,12 @@
+import MultiModuleStruct1
+import _Differentiation
+
+extension Struct : Differentiable {
+  @_alwaysEmitIntoClient
+  @derivative(of: sum)
+  public func _jvpSum() -> (
+    value: Float, differential: (Self.TangentVector) -> Float
+  ) {
+    (value: self.x, differential: { 42 * $0.x })
+  }
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/Inputs/SingleFileModule/file.swift b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/SingleFileModule/file.swift
new file mode 100644
index 0000000000000..6916329c88f03
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/Inputs/SingleFileModule/file.swift
@@ -0,0 +1,12 @@
+import _Differentiation
+
+@_alwaysEmitIntoClient
+public func f(_ x: Float) -> Float {
+  x
+}
+
+@derivative(of: f)
+@_alwaysEmitIntoClient
+public func df(_ x: Float) -> (value: Float, pullback: (Float) -> Float) {
+  (x, { 42 * $0 })
+}
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/multi_file.swift b/test/AutoDiff/validation-test/always_emit_into_client/multi_file.swift
new file mode 100644
index 0000000000000..504c5a5db98fd
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/multi_file.swift
@@ -0,0 +1,29 @@
+// REQUIRES: executable_test
+// RUN: %empty-directory(%t)
+
+/// Note: we build just a module without a library since it would not contain any exported
+/// symbols because all the functions in the module are marked as @_alwaysEmitIntoClient.
+// RUN: %target-build-swift %S/Inputs/MultiFileModule/file1.swift %S/Inputs/MultiFileModule/file2.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiFileModule.swiftmodule -module-name MultiFileModule
+
+// RUN: %target-build-swift -I%t %s -o %t/a.out %target-rpath(%t)
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out
+
+// RUN: %target-build-swift -I%t %s -emit-ir | %FileCheck %s
+
+import MultiFileModule
+import StdlibUnittest
+import _Differentiation
+
+var AlwaysEmitIntoClientTests = TestSuite("AlwaysEmitIntoClient")
+
+AlwaysEmitIntoClientTests.test("registration") {
+  expectEqual(42, gradient(at: 0, of: f))
+  expectEqual(42, gradient(at: 1, of: f))
+  expectEqual(42, gradient(at: 2, of: f))
+}
+
+runAllTests()
+
+// CHECK: @"15MultiFileModule1fyS2fFWJrSpSr" = weak_odr hidden {{()|local_unnamed_addr }}global { ptr, ptr } { ptr @"$s15MultiFileModule1fyS2fFTJfSpSr", ptr @"$s15MultiFileModule1fyS2fFTJrSpSr" }
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/multi_module.swift b/test/AutoDiff/validation-test/always_emit_into_client/multi_module.swift
new file mode 100644
index 0000000000000..4bf9895c1eb68
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/multi_module.swift
@@ -0,0 +1,34 @@
+// REQUIRES: executable_test
+// RUN: %empty-directory(%t)
+
+/// Note: we build just modules without libraries since they would not contain any exported
+/// symbols because all the functions in the module are marked as @_alwaysEmitIntoClient.
+// RUN: %target-build-swift-dylib(%t/%target-library-name(MultiModule1)) %S/Inputs/MultiModule/file1.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModule1.swiftmodule -module-name MultiModule1
+// RUN: %target-codesign %t/%target-library-name(MultiModule1)
+// RUN: %target-build-swift-dylib(%t/%target-library-name(MultiModule2)) %S/Inputs/MultiModule/file2.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModule2.swiftmodule -module-name MultiModule2 -I%t %target-rpath(%t)
+// RUN: %target-codesign %t/%target-library-name(MultiModule2)
+
+// RUN: %target-build-swift -I%t %s -o %t/a.out %target-rpath(%t)
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out %t/%target-library-name(MultiModule1) %t/%target-library-name(MultiModule2)
+
+// RUN: %target-build-swift -I%t %s -emit-ir | %FileCheck %s
+
+import MultiModule1
+import MultiModule2
+import StdlibUnittest
+import _Differentiation
+
+var AlwaysEmitIntoClientTests = TestSuite("AlwaysEmitIntoClient")
+
+AlwaysEmitIntoClientTests.test("registration") {
+  expectEqual(42, gradient(at: 0, of: f))
+  expectEqual(42, gradient(at: 1, of: f))
+  expectEqual(42, gradient(at: 2, of: f))
+}
+
+runAllTests()
+
+// CHECK: @"12MultiModule11fyS2fFWJrSpSr" = weak_odr hidden {{()|local_unnamed_addr }}global { ptr, ptr } { ptr @"$s12MultiModule11fyS2fFTJfSpSr", ptr @"$s12MultiModule11fyS2fFTJrSpSr" }
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/multi_module_protocol.swift b/test/AutoDiff/validation-test/always_emit_into_client/multi_module_protocol.swift
new file mode 100644
index 0000000000000..a5c4de74ba7c5
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/multi_module_protocol.swift
@@ -0,0 +1,47 @@
+// REQUIRES: executable_test
+// RUN: %empty-directory(%t)
+
+// RUN: %target-build-swift-dylib(%t/%target-library-name(MultiModuleProtocol1)) %S/Inputs/MultiModuleProtocol/file1.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModuleProtocol1.swiftmodule -module-name MultiModuleProtocol1
+// RUN: %target-codesign %t/%target-library-name(MultiModuleProtocol1)
+
+/// Note: we build just a module without a library since it would not contain any exported
+/// symbols because all the functions in the module are marked as @_alwaysEmitIntoClient.
+// RUN: %target-build-swift %S/Inputs/MultiModuleProtocol/file2.swift -emit-module -emit-module-path %t/MultiModuleProtocol2.swiftmodule \
+// RUN:   -module-name MultiModuleProtocol2 -I%t -lMultiModuleProtocol1 %target-rpath(%t)
+
+// RUN: %target-build-swift-dylib(%t/%target-library-name(MultiModuleProtocol3)) %S/Inputs/MultiModuleProtocol/file3.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModuleProtocol3.swiftmodule -module-name MultiModuleProtocol3 -I%t -L%t -lMultiModuleProtocol1 %target-rpath(%t)
+// RUN: %target-codesign %t/%target-library-name(MultiModuleProtocol3)
+
+/// Note: we enable forward-mode differentiation to automatically generate JVP for `foo`.
+/// It wraps `Protocol.sum` that has custom JVP defined in MultiModuleProtocol2, so we can test it.
+// RUN: %target-build-swift -Xfrontend -enable-experimental-forward-mode-differentiation \
+// RUN:   -I%t -L%t %s -lMultiModuleProtocol1 -lMultiModuleProtocol3 -o %t/a.out %target-rpath(%t)
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out %t/%target-library-name(MultiModuleProtocol1) %t/%target-library-name(MultiModuleProtocol3)
+
+// RUN: %target-build-swift -I%t %s -emit-ir | %FileCheck %s
+
+import MultiModuleProtocol1
+import MultiModuleProtocol2
+import MultiModuleProtocol3
+import StdlibUnittest
+import _Differentiation
+
+var AlwaysEmitIntoClientTests = TestSuite("AlwaysEmitIntoClient")
+
+AlwaysEmitIntoClientTests.test("registration") {
+  func foo<T: Protocol>(x: T) -> Float
+    where T: Differentiable, T.TangentVector == T { x.sum() }
+  expectEqual(Struct(42), pullback(at: Struct(0), of: foo)(1))
+  expectEqual(Struct(42), pullback(at: Struct(1), of: foo)(1))
+  expectEqual(Struct(42), pullback(at: Struct(2), of: foo)(1))
+  expectEqual(42, differential(at: Struct(0), of: foo)(Struct(1)))
+  expectEqual(42, differential(at: Struct(1), of: foo)(Struct(1)))
+  expectEqual(42, differential(at: Struct(2), of: foo)(Struct(1)))
+}
+
+runAllTests()
+
+// CHECK: @"20MultiModuleProtocol18ProtocolPAAE3sumSfyFAaBRz16_Differentiation14DifferentiableRz13TangentVectorAeFPQzRszlWJrSpSr" = weak_odr hidden {{()|local_unnamed_addr }}global { ptr, ptr } { ptr @"$s20MultiModuleProtocol18ProtocolPAAE3sumSfyFAaBRz16_Differentiation14DifferentiableRz13TangentVectorAeFPQzRszlTJfSpSr", ptr @"$s20MultiModuleProtocol18ProtocolPAAE3sumSfyFAaBRz16_Differentiation14DifferentiableRz13TangentVectorAeFPQzRszlTJrSpSr" }
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/multi_module_struct.swift b/test/AutoDiff/validation-test/always_emit_into_client/multi_module_struct.swift
new file mode 100644
index 0000000000000..f96054289818a
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/multi_module_struct.swift
@@ -0,0 +1,39 @@
+// REQUIRES: executable_test
+// RUN: %empty-directory(%t)
+
+// RUN: %target-build-swift-dylib(%t/%target-library-name(MultiModuleStruct1)) %S/Inputs/MultiModuleStruct/file1.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModuleStruct1.swiftmodule -module-name MultiModuleStruct1
+// RUN: %target-codesign %t/%target-library-name(MultiModuleStruct1)
+// RUN: %target-build-swift-dylib(%t/%target-library-name(MultiModuleStruct2)) %S/Inputs/MultiModuleStruct/file2.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModuleStruct2.swiftmodule -module-name MultiModuleStruct2 -I%t -L%t -lMultiModuleStruct1 %target-rpath(%t)
+// RUN: %target-codesign %t/%target-library-name(MultiModuleStruct2)
+
+/// Note: we enable forward-mode differentiation to automatically generate JVP for `foo`.
+/// It wraps `Struct.sum` that has custom JVP defined in MultiModuleStruct2, so we can test it.
+// RUN: %target-build-swift -Xfrontend -enable-experimental-forward-mode-differentiation \
+// RUN:   -I%t -L%t %s -lMultiModuleStruct1 -lMultiModuleStruct2 -o %t/a.out %target-rpath(%t)
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out %t/%target-library-name(MultiModuleStruct1) %t/%target-library-name(MultiModuleStruct2)
+
+// RUN: %target-build-swift -I%t %s -emit-ir | %FileCheck %s
+
+import MultiModuleStruct1
+import MultiModuleStruct2
+import StdlibUnittest
+import _Differentiation
+
+var AlwaysEmitIntoClientTests = TestSuite("AlwaysEmitIntoClient")
+
+AlwaysEmitIntoClientTests.test("registration") {
+  func foo(x: Struct) -> Float { x.sum() }
+  expectEqual(Struct(42), pullback(at: Struct(0), of: foo)(1))
+  expectEqual(Struct(42), pullback(at: Struct(1), of: foo)(1))
+  expectEqual(Struct(42), pullback(at: Struct(2), of: foo)(1))
+  expectEqual(42, differential(at: Struct(0), of: foo)(Struct(1)))
+  expectEqual(42, differential(at: Struct(1), of: foo)(Struct(1)))
+  expectEqual(42, differential(at: Struct(2), of: foo)(Struct(1)))
+}
+
+runAllTests()
+
+// CHECK: @"18MultiModuleStruct16StructV3sumSfyFWJrSpSr" = weak_odr hidden {{()|local_unnamed_addr }}global { ptr, ptr } { ptr @"$s18MultiModuleStruct16StructV3sumSfyFTJfSpSr", ptr @"$s18MultiModuleStruct16StructV3sumSfyFTJrSpSr" }
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/multi_module_struct_no_jvp.swift b/test/AutoDiff/validation-test/always_emit_into_client/multi_module_struct_no_jvp.swift
new file mode 100644
index 0000000000000..b75f11a9eec13
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/multi_module_struct_no_jvp.swift
@@ -0,0 +1,40 @@
+// REQUIRES: executable_test
+// RUN: %empty-directory(%t)
+
+// RUN: %target-build-swift-dylib(%t/%target-library-name(MultiModuleStruct1)) %S/Inputs/MultiModuleStruct/file1.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModuleStruct1.swiftmodule -module-name MultiModuleStruct1
+// RUN: %target-codesign %t/%target-library-name(MultiModuleStruct1)
+// RUN: %target-build-swift-dylib(%t/%target-library-name(MultiModuleStruct2NoJVP)) %S/Inputs/MultiModuleStruct/file2_no_jvp.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModuleStruct2NoJVP.swiftmodule -module-name MultiModuleStruct2NoJVP -I%t -L%t -lMultiModuleStruct1 %target-rpath(%t)
+// RUN: %target-codesign %t/%target-library-name(MultiModuleStruct2NoJVP)
+
+/// Note: we enable forward-mode differentiation to automatically generate JVP for `foo`.
+/// It wraps `Struct.sum` that has custom JVP defined in MultiModuleStruct2, so we can test it.
+// RUN: %target-build-swift -Xfrontend -enable-experimental-forward-mode-differentiation \
+// RUN:   -I%t -L%t %s -lMultiModuleStruct1 -lMultiModuleStruct2NoJVP -o %t/a.out %target-rpath(%t)
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out %t/%target-library-name(MultiModuleStruct1) %t/%target-library-name(MultiModuleStruct2NoJVP)
+
+// RUN: %target-build-swift -I%t %s -emit-ir | %FileCheck %s
+
+import MultiModuleStruct1
+import MultiModuleStruct2NoJVP
+import StdlibUnittest
+import _Differentiation
+
+var AlwaysEmitIntoClientTests = TestSuite("AlwaysEmitIntoClient")
+
+AlwaysEmitIntoClientTests.test("registration") {
+  func foo(x: Struct) -> Float { x.sum() }
+  expectEqual(Struct(42), pullback(at: Struct(0), of: foo)(1))
+  expectEqual(Struct(42), pullback(at: Struct(1), of: foo)(1))
+  expectEqual(Struct(42), pullback(at: Struct(2), of: foo)(1))
+  /// Custom JVP for Struct.sum is not provided, a JVP causing fatal error is emitted.
+  expectCrash{differential(at: Struct(0), of: foo)(Struct(1))}
+  expectCrash{differential(at: Struct(1), of: foo)(Struct(1))}
+  expectCrash{differential(at: Struct(2), of: foo)(Struct(1))}
+}
+
+runAllTests()
+
+// CHECK: @"18MultiModuleStruct16StructV3sumSfyFWJrSpSr" = weak_odr hidden {{()|local_unnamed_addr }}global { ptr, ptr } { ptr @"$s18MultiModuleStruct16StructV3sumSfyFTJfSpSr", ptr @"$s18MultiModuleStruct16StructV3sumSfyFTJrSpSr" }
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/multi_module_struct_no_vjp.swift b/test/AutoDiff/validation-test/always_emit_into_client/multi_module_struct_no_vjp.swift
new file mode 100644
index 0000000000000..a76ab04308b52
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/multi_module_struct_no_vjp.swift
@@ -0,0 +1,26 @@
+// REQUIRES: executable_test
+// RUN: %empty-directory(%t)
+
+// RUN: %target-build-swift-dylib(%t/%target-library-name(MultiModuleStruct1)) %S/Inputs/MultiModuleStruct/file1.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModuleStruct1.swiftmodule -module-name MultiModuleStruct1
+// RUN: not %target-build-swift-dylib(%t/%target-library-name(MultiModuleStruct2NoVJP)) %S/Inputs/MultiModuleStruct/file2_no_vjp.swift \
+// RUN:   -emit-module -emit-module-path %t/MultiModuleStruct2NoVJP.swiftmodule -module-name MultiModuleStruct2NoVJP -I%t -L%t -lMultiModuleStruct1 %target-rpath(%t) 2>&1 | \
+// RUN:   %FileCheck %s
+
+// CHECK: file2_no_vjp.swift:6:4: error: function is not differentiable
+
+import MultiModuleStruct1
+import MultiModuleStruct2
+import StdlibUnittest
+import _Differentiation
+
+var AlwaysEmitIntoClientTests = TestSuite("AlwaysEmitIntoClient")
+
+AlwaysEmitIntoClientTests.test("registration") {
+  func foo(x: Struct) -> Float { x.sum() }
+  expectEqual(42, differential(at: Struct(0), of: foo)(Struct(1)))
+  expectEqual(42, differential(at: Struct(1), of: foo)(Struct(1)))
+  expectEqual(42, differential(at: Struct(2), of: foo)(Struct(1)))
+}
+
+runAllTests()
diff --git a/test/AutoDiff/validation-test/always_emit_into_client/single_file.swift b/test/AutoDiff/validation-test/always_emit_into_client/single_file.swift
new file mode 100644
index 0000000000000..aab005aad9b96
--- /dev/null
+++ b/test/AutoDiff/validation-test/always_emit_into_client/single_file.swift
@@ -0,0 +1,29 @@
+// REQUIRES: executable_test
+// RUN: %empty-directory(%t)
+
+/// Note: we build just a module without a library since it would not contain any exported
+/// symbols because all the functions in the module are marked as @_alwaysEmitIntoClient.
+// RUN: %target-build-swift %S/Inputs/SingleFileModule/file.swift -emit-module \
+// RUN:   -emit-module-path %t/SingleFileModule.swiftmodule -module-name SingleFileModule
+
+// RUN: %target-build-swift -I%t %s -o %t/a.out %target-rpath(%t)
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out
+
+// RUN: %target-build-swift -I%t %s -emit-ir | %FileCheck %s
+
+import SingleFileModule
+import StdlibUnittest
+import _Differentiation
+
+var AlwaysEmitIntoClientTests = TestSuite("AlwaysEmitIntoClient")
+
+AlwaysEmitIntoClientTests.test("registration") {
+  expectEqual(42, gradient(at: 0, of: f))
+  expectEqual(42, gradient(at: 1, of: f))
+  expectEqual(42, gradient(at: 2, of: f))
+}
+
+runAllTests()
+
+// CHECK: @"16SingleFileModule1fyS2fFWJrSpSr" = weak_odr hidden {{()|local_unnamed_addr }}global { ptr, ptr } { ptr @"$s16SingleFileModule1fyS2fFTJfSpSr", ptr @"$s16SingleFileModule1fyS2fFTJrSpSr" }
diff --git a/test/AutoDiff/validation-test/closure_specialization/multi_bb_bte.swift b/test/AutoDiff/validation-test/closure_specialization/multi_bb_bte.swift
new file mode 100644
index 0000000000000..09bbf487a87b8
--- /dev/null
+++ b/test/AutoDiff/validation-test/closure_specialization/multi_bb_bte.swift
@@ -0,0 +1,135 @@
+/// Multi basic block VJP, pullback accepting branch tracing enum argument.
+
+// REQUIRES: executable_test
+
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -o %t/none.out -Onone
+// RUN: %target-build-swift %s -o %t/opt.out  -O
+// RUN: %target-codesign %t/none.out
+// RUN: %target-codesign %t/opt.out
+// RUN: %target-run %t/none.out
+// RUN: %target-run %t/opt.out
+
+// RUN: %target-swift-frontend -emit-sil %s -O -o %t/out.sil
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK1
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK2
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK3
+
+import DifferentiationUnittest
+import StdlibUnittest
+
+var AutoDiffClosureSpecMultiBBBTETests = TestSuite("AutoDiffClosureSpecMultiBBBTE")
+
+AutoDiffClosureSpecMultiBBBTETests.testWithLeakChecking("Test1") {
+  // CHECK1-LABEL: {{^}}// reverse-mode derivative of mul42 #1 (_:)
+  // CHECK1-NEXT:  sil private @$s3outyycfU_5mul42L_yS2fSgFTJrSpSr : $@convention(thin) (Optional<Float>) -> (Float, @owned @callee_guaranteed (Float) -> Optional<Float>.TangentVector) {
+  // CHECK1:         %[[#A12:]] = function_ref @$s3outyycfU_5mul42L_yS2fSgFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_S2fTf1nnc_n : $@convention(thin) (Float, @owned _AD__$s3outyycfU_5mul42L_yS2fSgF_bb2__Pred__src_0_wrt_0, Float, Float) -> Optional<Float>.TangentVector
+  // CHECK1:         %[[#A13:]] = partial_apply [callee_guaranteed] %[[#A12]](%[[#]], %[[#]], %[[#]]) : $@convention(thin) (Float, @owned _AD__$s3outyycfU_5mul42L_yS2fSgF_bb2__Pred__src_0_wrt_0, Float, Float) -> Optional<Float>.TangentVector
+  // CHECK1:         %[[#A14:]] = tuple (%[[#]], %[[#A13]])
+  // CHECK1:         return %[[#A14]]
+  // CHECK1:       } // end sil function '$s3outyycfU_5mul42L_yS2fSgFTJrSpSr'
+
+  // CHECK1-NONE:  {{^}}// pullback of mul42
+  // CHECK1:       {{^}}// specialized pullback of mul42
+  // CHECK1:       sil private @$s3outyycfU_5mul42L_yS2fSgFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_S2fTf1nnc_n : $@convention(thin) (Float, @owned _AD__$s3outyycfU_5mul42L_yS2fSgF_bb2__Pred__src_0_wrt_0, Float, Float) -> Optional<Float>.TangentVector {
+
+  @differentiable(reverse)
+  func mul42(_ a: Float?) -> Float {
+    let b = 42 * a!
+    return b
+  }
+
+  expectEqual((-84, 42), valueWithGradient(at: -2, of: mul42))
+  expectEqual((0, 42), valueWithGradient(at: 0, of: mul42))
+  expectEqual((42, 42), valueWithGradient(at: 1, of: mul42))
+  expectEqual((210, 42), valueWithGradient(at: 5, of: mul42))
+}
+
+AutoDiffClosureSpecMultiBBBTETests.testWithLeakChecking("Test2") {
+  // CHECK2-LABEL: {{^}}// reverse-mode derivative of cond_tuple_var #1 (_:)
+  // CHECK2-NEXT:  sil private @$s3outyycfU0_14cond_tuple_varL_yS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK2:         %[[#E41:]] = function_ref @$s3outyycfU0_14cond_tuple_varL_yS2fFTJpSpSr067$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktl1_m5FZSf_M6SfcfU_0ef1_g4E12_i16Subtract3lhs3rhsk1_l1_mnl1_mo1_mP2U_ACTf1nnccc_n : $@convention(thin) (Float, @owned _AD__$s3outyycfU0_14cond_tuple_varL_yS2fF_bb3__Pred__src_0_wrt_0) -> Float
+  // CHECK2:         %[[#E42:]] = partial_apply [callee_guaranteed] %[[#E41]](%[[#]]) : $@convention(thin) (Float, @owned _AD__$s3outyycfU0_14cond_tuple_varL_yS2fF_bb3__Pred__src_0_wrt_0) -> Float
+  // CHECK2:         %[[#E46:]] = tuple (%[[#]], %[[#E42]])
+  // CHECK2:         return %[[#E46]]
+  // CHECK2:       } // end sil function '$s3outyycfU0_14cond_tuple_varL_yS2fFTJrSpSr'
+
+  // CHECK2-NONE:  {{^}}// pullback of cond_tuple_var
+  // CHECK2:       {{^}}// specialized pullback of cond_tuple_var
+  // CHECK2:       sil private @$s3outyycfU0_14cond_tuple_varL_yS2fFTJpSpSr067$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktl1_m5FZSf_M6SfcfU_0ef1_g4E12_i16Subtract3lhs3rhsk1_l1_mnl1_mo1_mP2U_ACTf1nnccc_n : $@convention(thin) (Float, @owned _AD__$s3outyycfU0_14cond_tuple_varL_yS2fF_bb3__Pred__src_0_wrt_0) -> Float {
+
+  func cond_tuple_var(_ x: Float) -> Float {
+    // Convoluted function returning `x + x`.
+    var y: (Float, Float) = (x, x)
+    var z: (Float, Float) = (x + x, x - x)
+    if x > 0 {
+      var w = (x, x)
+      y.0 = w.1
+      y.1 = w.0
+      z.0 = z.0 - y.0
+      z.1 = z.1 + y.0
+    } else {
+      z = (1 * x, x)
+    }
+    return y.0 + y.1 - z.0 + z.1
+  }
+
+  expectEqual((8, 2), valueWithGradient(at: 4, of: cond_tuple_var))
+  expectEqual((-20, 2), valueWithGradient(at: -10, of: cond_tuple_var))
+  expectEqual((-2674, 2), valueWithGradient(at: -1337, of: cond_tuple_var))
+}
+
+AutoDiffClosureSpecMultiBBBTETests.testWithLeakChecking("Test3") {
+  struct Class: Differentiable {
+    var stored: Float
+    var optional: Float?
+
+    init(stored: Float, optional: Float?) {
+      self.stored = stored
+      self.optional = optional
+    }
+
+    // CHECK3-LABEL: {{^}}// reverse-mode derivative of method()
+    // CHECK3-NEXT:  sil private @$s3outyycfU1_5ClassL_V6methodSfyFTJrSpSr : $@convention(method) (Class) -> (Float, @owned @callee_guaranteed (Float) -> Class.TangentVector) {
+    // CHECK3:         %[[#C44:]] = function_ref @$s3outyycfU1_5ClassL_V6methodSfyFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktk1_l5FZSf_L6SfcfU_S2fAES2fTf1nncc_n : $@convention(thin) (Float, @owned _AD__$s3outyycfU1_5ClassL_V6methodSfyF_bb3__Pred__src_0_wrt_0, Float, Float, Float, Float) -> Class.TangentVector
+    // CHECK3:         %[[#C45:]] = partial_apply [callee_guaranteed] %[[#C44]](%[[#]], %[[#]], %[[#]], %[[#]], %[[#]]) : $@convention(thin) (Float, @owned _AD__$s3outyycfU1_5ClassL_V6methodSfyF_bb3__Pred__src_0_wrt_0, Float, Float, Float, Float) -> Class.TangentVector
+    // CHECK3:         %[[#C48:]] = tuple (%[[#]], %[[#C45]])
+    // CHECK3:         return %[[#C48]]
+    // CHECK3:       } // end sil function '$s3outyycfU1_5ClassL_V6methodSfyFTJrSpSr'
+
+    // CHECK3-NONE:  {{^}}// pullback of method
+    // CHECK3:       {{^}}// specialized pullback of method()
+    // CHECK3:       sil private @$s3outyycfU1_5ClassL_V6methodSfyFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktk1_l5FZSf_L6SfcfU_S2fAES2fTf1nncc_n : $@convention(thin) (Float, @owned _AD__$s3outyycfU1_5ClassL_V6methodSfyF_bb3__Pred__src_0_wrt_0, Float, Float, Float, Float) -> Class.TangentVector {
+
+    @differentiable(reverse)
+    func method() -> Float {
+      let c: Class
+      do {
+        let tmp = Class(stored: 1 * stored, optional: optional)
+        let tuple = (tmp, tmp)
+        c = tuple.0
+      }
+      var ret : Float = 0
+      if let x = c.optional {
+        ret = x * c.stored
+      } else {
+        ret = 1 * c.stored
+      }
+      return 1 * ret * ret
+    }
+  }
+
+  @differentiable(reverse)
+  func methodWrapper(_ x: Class) -> Float {
+    x.method()
+  }
+
+  expectEqual(
+    valueWithGradient(at: Class(stored: 3, optional: 4), of: methodWrapper),
+    (144, .init(stored: 96, optional: .init(72))))
+  expectEqual(
+    valueWithGradient(at: Class(stored: 3, optional: nil), of: methodWrapper),
+    (9, .init(stored: 6, optional: .init(0))))
+}
+
+runAllTests()
diff --git a/test/AutoDiff/validation-test/closure_specialization/multi_bb_no_bte.swift b/test/AutoDiff/validation-test/closure_specialization/multi_bb_no_bte.swift
new file mode 100644
index 0000000000000..9cca3225d3a38
--- /dev/null
+++ b/test/AutoDiff/validation-test/closure_specialization/multi_bb_no_bte.swift
@@ -0,0 +1,195 @@
+/// Multi basic block VJP, pullback not accepting branch tracing enum argument.
+
+// REQUIRES: executable_test
+
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -o %t/none.out -Onone
+// RUN: %target-build-swift %s -o %t/opt.out  -O
+// RUN: %target-codesign %t/none.out
+// RUN: %target-codesign %t/opt.out
+// RUN: %target-run %t/none.out
+// RUN: %target-run %t/opt.out
+
+// RUN: %target-swift-frontend -emit-sil %s -O -o %t/out.sil
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK1
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK2
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK3
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK4
+
+// TODO: re-enable this test once we have OSSA throughout the pipeline
+// XFAIL: *
+
+import DifferentiationUnittest
+import StdlibUnittest
+
+var AutoDiffClosureSpecMultiBBNoBTETests = TestSuite("AutoDiffClosureSpecMultiBBNoBTE")
+
+typealias FloatArrayTan = Array<Float>.TangentVector
+
+AutoDiffClosureSpecMultiBBNoBTETests.testWithLeakChecking("Test1") {
+  // CHECK1-LABEL: {{^}}// reverse-mode derivative of sumFirstThreeConcatenating1 #1 (_:_:)
+  // CHECK1-NEXT:  sil private @$s3outyycfU_27sumFirstThreeConcatenating1L_ySfSaySfG_ACtFTJrSSpSr : $@convention(thin) (@guaranteed Array<Float>, @guaranteed Array<Float>) -> (Float, @owned @callee_guaranteed (Float) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)) {
+  // CHECK1:         %[[#E52:]] = function_ref @$s3outyycfU_27sumFirstThreeConcatenating1L_ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyg8_GIegno_G10AEIegyo_TRSfSa01_I0AE0K0RzlE0kO0VySf_GIegno_ADSfAIIegno_0f5Sf16_i26E7_vjpAdd3lhs3rhsSf5value_g17_SftSfc8pullbacktg1_y5FZSf_Y6SfcfU_ADSfAIIegno_AJTf1nnccccc_n0fh1_ijkl4E13_v32Subscript5indexx5value_SaA2aBRzlmnO59Vy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaBRzlFSf_TG5ACSiAkCSiAkCSiTf1nnccc_n : $@convention(thin) (Float, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned Array<Float>, Int, @owned Array<Float>, Int, @owned Array<Float>, Int) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  // CHECK1:         %[[#E53:]] = partial_apply [callee_guaranteed] %[[#E52]](%[[#]], %[[#]], %[[#]], %[[#]], %[[#]], %[[#]], %[[#]]) : $@convention(thin) (Float, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned Array<Float>, Int, @owned Array<Float>, Int, @owned Array<Float>, Int) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  // CHECK1:         %[[#E55:]] = tuple (%[[#]], %[[#E53]])
+  // CHECK1:         return %[[#E55]]
+  // CHECK1:       } // end sil function '$s3outyycfU_27sumFirstThreeConcatenating1L_ySfSaySfG_ACtFTJrSSpSr'
+
+  // CHECK1-NONE:  {{^}}// pullback of sumFirstThreeConcatenating1
+  // CHECK1:       {{^}}// specialized pullback of sumFirstThreeConcatenating1
+  // CHECK1:       sil private @$s3outyycfU_27sumFirstThreeConcatenating1L_ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyg8_GIegno_G10AEIegyo_TRSfSa01_I0AE0K0RzlE0kO0VySf_GIegno_ADSfAIIegno_0f5Sf16_i26E7_vjpAdd3lhs3rhsSf5value_g17_SftSfc8pullbacktg1_y5FZSf_Y6SfcfU_ADSfAIIegno_AJTf1nnccccc_n0fh1_ijkl4E13_v32Subscript5indexx5value_SaA2aBRzlmnO59Vy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaBRzlFSf_TG5ACSiAkCSiAkCSiTf1nnccc_nTf4ngnnnnnn_n : $@convention(thin) (Float, @guaranteed @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned Array<Float>, Int, @owned Array<Float>, Int, @owned Array<Float>, Int) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView) {
+  func sumFirstThreeConcatenating1(_ a: [Float], _ b: [Float]) -> Float {
+    let c = a + b
+    return c[0] + c[1] + c[2]
+  }
+
+  expectEqual(
+    (.init([1, 1]), .init([1, 0])),
+    gradient(at: [0, 0], [0, 0], of: sumFirstThreeConcatenating1))
+  expectEqual(
+    (.init([1, 1, 1, 0]), .init([0, 0])),
+    gradient(at: [0, 0, 0, 0], [0, 0], of: sumFirstThreeConcatenating1))
+  expectEqual(
+    (.init([]), .init([1, 1, 1, 0])),
+    gradient(at: [], [0, 0, 0, 0], of: sumFirstThreeConcatenating1))
+}
+
+AutoDiffClosureSpecMultiBBNoBTETests.testWithLeakChecking("Test2") {
+  // CHECK2-LABEL: {{^}}// reverse-mode derivative of sumFirstThreeConcatenating2 #1 (_:_:)
+  // CHECK2-NEXT:  sil private @$s3outyycfU0_27sumFirstThreeConcatenating2L_ySfSaySfG_ACtFTJrSSpSr : $@convention(thin) (@guaranteed Array<Float>, @guaranteed Array<Float>) -> (Float, @owned @callee_guaranteed (Float) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)) {
+  // CHECK2:         %[[#E52:]] = function_ref @$s3outyycfU0_27sumFirstThreeConcatenating2L_ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyg8_GIegno_G10AEIegyo_TRSfSa01_I0AE0K0RzlE0kO0VySf_GIegno_ADSfAIIegno_0f5Sf16_i26E7_vjpAdd3lhs3rhsSf5value_g17_SftSfc8pullbacktg1_y5FZSf_Y6SfcfU_ADSfAIIegno_AJTf1nnccccc_n0fh1_ijkl4E10_v25Appendyyt5value_SaA2aBRzlmno55Vy13TangentVectorQz_GAIzc8pullbacktSayxGz_AKtFZA2IzcfU_G4_Tg5Si0fh1_ijkl4E13_v32Subscript5indexx5value_SaA2aBRzlmnO59Vy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaBRzlFSf_TG5ACSiAlCSiAlCSiTf1ncccc_n : $@convention(thin) (Float, Int, @owned Array<Float>, Int, @owned Array<Float>, Int, @owned Array<Float>, Int) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  // CHECK2:         %[[#E53:]] = partial_apply [callee_guaranteed] %[[#E52]](%[[#]], %[[#]], %[[#]], %[[#]], %[[#]], %[[#]], %[[#]]) : $@convention(thin) (Float, Int, @owned Array<Float>, Int, @owned Array<Float>, Int, @owned Array<Float>, Int) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView)
+  // CHECK2:         %[[#E55:]] = tuple (%[[#]], %[[#E53]])
+  // CHECK2:         return %[[#E55]]
+  // CHECK2:       } // end sil function '$s3outyycfU0_27sumFirstThreeConcatenating2L_ySfSaySfG_ACtFTJrSSpSr'
+
+  // CHECK2-NONE:  {{^}}// pullback of sumFirstThreeConcatenating2
+  // CHECK2:       {{^}}// specialized pullback of sumFirstThreeConcatenating2
+  // CHECK2:       sil private @$s3outyycfU0_27sumFirstThreeConcatenating2L_ySfSaySfG_ACtFTJpSSpSr055$sSfSa16_DifferentiationAA14DifferentiableRzlE0B4ViewVyg8_GIegno_G10AEIegyo_TRSfSa01_I0AE0K0RzlE0kO0VySf_GIegno_ADSfAIIegno_0f5Sf16_i26E7_vjpAdd3lhs3rhsSf5value_g17_SftSfc8pullbacktg1_y5FZSf_Y6SfcfU_ADSfAIIegno_AJTf1nnccccc_n0fh1_ijkl4E10_v25Appendyyt5value_SaA2aBRzlmno55Vy13TangentVectorQz_GAIzc8pullbacktSayxGz_AKtFZA2IzcfU_G4_Tg5Si0fh1_ijkl4E13_v32Subscript5indexx5value_SaA2aBRzlmnO59Vy13TangentVectorQz_GAIc8pullbacktSi_tFAKL_yAjiaBRzlFSf_TG5ACSiAlCSiAlCSiTf1ncccc_n : $@convention(thin) (Float, Int, @owned Array<Float>, Int, @owned Array<Float>, Int, @owned Array<Float>, Int) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView) {
+
+  func sumFirstThreeConcatenating2(_ a: [Float], _ b: [Float]) -> Float {
+    var c = a
+    c += b
+    return c[0] + c[1] + c[2]
+  }
+
+  expectEqual(
+    (.init([1, 1]), .init([1, 0])),
+    gradient(at: [0, 0], [0, 0], of: sumFirstThreeConcatenating2))
+  expectEqual(
+    (.init([1, 1, 1, 0]), .init([0, 0])),
+    gradient(at: [0, 0, 0, 0], [0, 0], of: sumFirstThreeConcatenating2))
+  expectEqual(
+    (.init([]), .init([1, 1, 1, 0])),
+    gradient(at: [], [0, 0, 0, 0], of: sumFirstThreeConcatenating2))
+}
+
+AutoDiffClosureSpecMultiBBNoBTETests.testWithLeakChecking("Test3") {
+  @propertyWrapper
+  enum Wrapper {
+    case case1(Float)
+    case case2(Float)
+
+    init(wrappedValue: Float) {
+      self = .case1(wrappedValue)
+    }
+
+    var wrappedValue: Float {
+      get {
+        switch self {
+        case .case1(let val):
+          return val
+        case .case2(let val):
+          return val * 2
+        }
+      }
+      set {
+        self = .case2(wrappedValue)
+      }
+    }
+  }
+
+  struct RealPropertyWrappers: Differentiable {
+    @Wrapper var x: Float = 3
+    var y: Float = 4
+  }
+
+  // CHECK3:       {{^}}// reverse-mode derivative of multiply #1 (_:)
+  // CHECK3-NEXT:  sil private @$s3outyycfU1_8multiplyL_ySfAAyycfU1_20RealPropertyWrappersL_VFTJrSpSr : $@convention(thin) (RealPropertyWrappers) -> (Float, @owned @callee_guaranteed (Float) -> RealPropertyWrappers.TangentVector) {
+  // CHECK3:         %[[#A22:]] = function_ref @$s3outyycfU1_8multiplyL_ySfAAyycfU1_20RealPropertyWrappersL_VFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktm1_n5FZSf_N6SfcfU_S2fTf1nnc_n015$s3outyycfU1_20cdE16L_V1xSfvgTJpSpSrTf1ncnn_n : $@convention(thin) (Float, Float, Float) -> RealPropertyWrappers.TangentVector
+  // CHECK3:         %[[#A23:]] = partial_apply [callee_guaranteed] %[[#A22]](%[[#]], %[[#]]) : $@convention(thin) (Float, Float, Float) -> RealPropertyWrappers.TangentVector
+  // CHECK3:         %[[#A24:]] = tuple (%[[#]], %[[#A23]])
+  // CHECK3:         return %[[#A24]]
+  // CHECK3:       } // end sil function '$s3outyycfU1_8multiplyL_ySfAAyycfU1_20RealPropertyWrappersL_VFTJrSpSr'
+
+  // CHECK3-NONE:  {{^}}// pullback of multiply
+  // CHECK3:       {{^}}// specialized pullback of multiply
+  // CHECK3:       sil private @$s3outyycfU1_8multiplyL_ySfAAyycfU1_20RealPropertyWrappersL_VFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktm1_n5FZSf_N6SfcfU_S2fTf1nnc_n015$s3outyycfU1_20cdE16L_V1xSfvgTJpSpSrTf1ncnn_n : $@convention(thin) (Float, Float, Float) -> RealPropertyWrappers.TangentVector {
+
+  @differentiable(reverse)
+  func multiply(_ s: RealPropertyWrappers) -> Float {
+    return s.x * s.y
+  }
+
+  expectEqual(
+    .init(x: 4, y: 3),
+    gradient(at: RealPropertyWrappers(x: 3, y: 4), of: multiply))
+}
+
+AutoDiffClosureSpecMultiBBNoBTETests.testWithLeakChecking("Test4") {
+  struct Class: Differentiable {
+    var stored: Float
+    var optional: Float?
+
+    init(stored: Float, optional: Float?) {
+      self.stored = stored
+      self.optional = optional
+    }
+
+    @differentiable(reverse)
+    func method() -> Float {
+      let c: Class
+      do {
+        let tmp = Class(stored: 1 * stored, optional: optional)
+        let tuple = (tmp, tmp)
+        c = tuple.0
+      }
+      if let x = c.optional {
+        return x * c.stored
+      }
+      return 1 * c.stored
+    }
+  }
+
+  // CHECK4-LABEL: {{^}}// reverse-mode derivative of methodWrapper #1 (_:)
+  // CHECK4-NEXT:  sil private @$s3outyycfU2_13methodWrapperL_ySfAAyycfU2_5ClassL_VFTJrSpSr : $@convention(thin) (Class) -> (Float, @owned @callee_guaranteed (Float) -> Class.TangentVector) {
+  // CHECK4:         %[[#C39:]] = function_ref @$s3outyycfU2_13methodWrapperL_ySfAAyycfU2_5ClassL_VFTJpSpSr014$s3outyycfU2_5D21L_V6methodSfyFTJpSpSrAA05_AD__ef2_5d2L_gH24F_bb3__Pred__src_0_wrt_033_E588B908471A5F020CF23EC392ADD7D3LLOTf1nc_n : $@convention(thin) (Float, @owned _AD__$s3outyycfU2_5ClassL_V6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector 
+  // CHECK4:         %[[#C40:]] = partial_apply [callee_guaranteed] %[[#C39]](%[[#]]) : $@convention(thin) (Float, @owned _AD__$s3outyycfU2_5ClassL_V6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector
+  // CHECK4:         %[[#C42:]] = tuple (%[[#]], %[[#C40]])
+  // CHECK4:         return %[[#C42]]
+  // CHECK4:       } // end sil function '$s3outyycfU2_13methodWrapperL_ySfAAyycfU2_5ClassL_VFTJrSpSr'
+
+  /// TODO: even though branch tracing enum is not passed to top-level pullback
+  /// directly, it is captured by one of the closures which was specialized.
+  /// Because of that, this enum argument is now an argument of specialized top-level
+  /// pullback. Specializing closures passed as payload tuple elements of the enum
+  /// is currently not supported.
+
+  // CHECK4-NONE:  {{^}}// pullback of methodWrapper
+  // CHECK4:       {{^}}// specialized pullback of methodWrapper
+  // CHECK4:       sil private @$s3outyycfU2_13methodWrapperL_ySfAAyycfU2_5ClassL_VFTJpSpSr014$s3outyycfU2_5D21L_V6methodSfyFTJpSpSrAA05_AD__ef2_5d2L_gH24F_bb3__Pred__src_0_wrt_033_E588B908471A5F020CF23EC392ADD7D3LLOTf1nc_n : $@convention(thin) (Float, @owned _AD__$s3outyycfU2_5ClassL_V6methodSfyF_bb3__Pred__src_0_wrt_0) -> Class.TangentVector {
+
+  @differentiable(reverse)
+  func methodWrapper(_ x: Class) -> Float {
+    x.method()
+  }
+
+  expectEqual(
+    valueWithGradient(at: Class(stored: 3, optional: 4), of: methodWrapper),
+    (12, .init(stored: 4, optional: .init(3))))
+  expectEqual(
+    valueWithGradient(at: Class(stored: 3, optional: nil), of: methodWrapper),
+    (3, .init(stored: 1, optional: .init(0))))
+}
+
+runAllTests()
diff --git a/test/AutoDiff/validation-test/closure_specialization/single_bb1.swift b/test/AutoDiff/validation-test/closure_specialization/single_bb1.swift
new file mode 100644
index 0000000000000..17743de57e1d5
--- /dev/null
+++ b/test/AutoDiff/validation-test/closure_specialization/single_bb1.swift
@@ -0,0 +1,117 @@
+/// Single basic block VJP.
+
+// REQUIRES: executable_test
+// UNSUPPORTED: OS=windows-msvc
+
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -o %t/none.out -Onone
+// RUN: %target-build-swift %s -o %t/opt.out  -O
+// RUN: %target-codesign %t/none.out
+// RUN: %target-codesign %t/opt.out
+// RUN: %target-run %t/none.out
+// RUN: %target-run %t/opt.out
+
+// RUN: %target-swift-frontend -emit-sil %s -O -o %t/out.sil
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK1
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK2
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK3
+
+import DifferentiationUnittest
+import StdlibUnittest
+
+#if canImport(Glibc)
+import Glibc
+#elseif canImport(Android)
+import Android
+#else
+import Foundation
+#endif
+
+var AutoDiffClosureSpecSingleBBTests = TestSuite("AutoDiffClosureSpecSingleBB")
+
+AutoDiffClosureSpecSingleBBTests.testWithLeakChecking("Test1") {
+  // CHECK1-LABEL: {{^}}// reverse-mode derivative of test1 #1 (_:)
+  // CHECK1-NEXT:  sil private @$s3outyycfU_5test1L_yS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK1:         %[[#A10:]] = function_ref @$s3outyycfU_5test1L_yS2fFTJpSpSr62$s16_Differentiation7_vjpSinySf5value_S2fc8pullbacktSfFS2fcfU_Sf0c1_d1_e4Cosyg1_hiJ2U_Sf026$sSf16_DifferentiationE12_e16Multiply3lhs3rhsg1_i17_SftSfc8pullbackti1_q5FZSf_Q6SfcfU_S2fTf1nccc_n : $@convention(thin) (Float, Float, Float, Float, Float) -> Float
+  // CHECK1:         %[[#A11:]] = partial_apply [callee_guaranteed] %[[#A10]](%[[#]], %[[#]], %[[#]], %[[#]]) : $@convention(thin) (Float, Float, Float, Float, Float) -> Float
+  // CHECK1:         %[[#A12:]] = tuple (%[[#]], %[[#A11]])
+  // CHECK1:         return %[[#A12]]
+  // CHECK1:       } // end sil function '$s3outyycfU_5test1L_yS2fFTJrSpSr'
+
+  // CHECK1-NONE:  {{^}}// pullback of test1 #1 (_:)
+  // CHECK1:       {{^}}// specialized pullback of test1 #1 (_:)
+  // CHECK1:       sil private @$s3outyycfU_5test1L_yS2fFTJpSpSr62$s16_Differentiation7_vjpSinySf5value_S2fc8pullbacktSfFS2fcfU_Sf0c1_d1_e4Cosyg1_hiJ2U_Sf026$sSf16_DifferentiationE12_e16Multiply3lhs3rhsg1_i17_SftSfc8pullbackti1_q5FZSf_Q6SfcfU_S2fTf1nccc_n : $@convention(thin) (Float, Float, Float, Float, Float) -> Float {
+
+  @differentiable(reverse)
+  func test1(_ x: Float) -> Float {
+    return sin(x) * cos(x)
+  }
+
+  func test1Derivative(_ x: Float) -> Float {
+    return cos(x) * cos(x) - sin(x) * sin(x)
+  }
+
+  for x in -100...100 {
+    expectEqual((1000 * gradient(at: Float(x), of: test1)).rounded(), (1000 * test1Derivative(Float(x))).rounded())
+  }
+}
+
+AutoDiffClosureSpecSingleBBTests.testWithLeakChecking("Test2") {
+  // CHECK2-LABEL: {{^}}// reverse-mode derivative of test2 #1 (_:)
+  // CHECK2-NEXT:  sil private @$s3outyycfU0_5test2L_yS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK2:         %[[#B19:]] = function_ref @$s3outyycfU0_5test2L_yS2fFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_S2f022$s16_Differentiation7_g4Sinyi15_S2fc8pullbacktJ8FS2fcfU_SfADSf0o1_p1_g4Cosyi1_rjS2U_SfACS2fAESf0cd1_e3E7_g11Add3lhs3rhsi1_j1_klj1_km1_kN2U_Tf1nccccccc_n : $@convention(thin) (Float, Float, Float, Float, Float, Float, Float, Float, Float) -> Float
+  // CHECK2:         %[[#B20:]] = partial_apply [callee_guaranteed] %[[#B19]](%[[#]], %[[#]], %[[#]], %[[#]], %[[#]], %[[#]], %[[#]], %[[#]]) : $@convention(thin) (Float, Float, Float, Float, Float, Float, Float, Float, Float) -> Float
+  // CHECK2:         %[[#B21:]] = tuple (%[[#]], %[[#B20]])
+  // CHECK2:         return %[[#B21]]
+  // CHECK2:       } // end sil function '$s3outyycfU0_5test2L_yS2fFTJrSpSr'
+
+  // CHECK2-NONE:  {{^}}// pullback of test2 #1 (_:)
+  // CHECK2:       {{^}}// specialized pullback of test2 #1 (_:)
+  // CHECK2:       sil private @$s3outyycfU0_5test2L_yS2fFTJpSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_S2f022$s16_Differentiation7_g4Sinyi15_S2fc8pullbacktJ8FS2fcfU_SfADSf0o1_p1_g4Cosyi1_rjS2U_SfACS2fAESf0cd1_e3E7_g11Add3lhs3rhsi1_j1_klj1_km1_kN2U_Tf1nccccccc_n : $@convention(thin) (Float, Float, Float, Float, Float, Float, Float, Float, Float) -> Float {
+
+  @differentiable(reverse)
+  func test2(_ x: Float) -> Float {
+    return sin(37 * x) * cos(sin(x)) + cos(x)
+  }
+
+  func test2Derivative(_ x: Float) -> Float {
+    return -cos(x)*sin(37*x)*sin(sin(x)) + 37*cos(37*x)*cos(sin(x)) - sin(x)
+  }
+
+  for x in -100...100 {
+    expectEqual((1000 * gradient(at: Float(x), of: test2)).rounded(), (1000 * test2Derivative(Float(x))).rounded())
+  }
+}
+
+AutoDiffClosureSpecSingleBBTests.testWithLeakChecking("Test3") {
+  // CHECK3-LABEL: {{^}}// reverse-mode derivative of test3 #1 (_:_:_:)
+  // CHECK3-NEXT:  sil private @$s3outyycfU1_5test3L_yS2f_S2ftFTJrSSSpSr : $@convention(thin) (Float, Float, Float) -> (Float, @owned @callee_guaranteed (Float) -> (Float, Float, Float)) {
+  // CHECK3:         %[[#C18:]] = function_ref @$s3outyycfU1_5test3L_yS2f_S2ftFTJpSSSpSr62$s16_Differentiation7_vjpSinySf5value_S2fc8pullbacktSfFS2fcfU_Sf0c1_d1_e4Cosyg1_hiJ2U_Sf025$sSf16_DifferentiationE7_e11Add3lhs3rhsg1_i17_SftSfc8pullbackti1_q5FZSf_Q6SfcfU_0c1_d1_e4Tanyg1_hiJ2U_Sf0lm1_n4E12_e16Subtract3lhs3rhsg1_i1_qri1_qs1_qT2U_Tf1nccccc_n : $@convention(thin) (Float, Float, Float, Float) -> (Float, Float, Float)
+  // CHECK3:         %[[#C19:]] = partial_apply [callee_guaranteed] %[[#C18]](%[[#]], %[[#]], %[[#]]) : $@convention(thin) (Float, Float, Float, Float) -> (Float, Float, Float)
+  // CHECK3:         %[[#C20:]] = tuple (%[[#]], %[[#C19]])
+  // CHECK3:         return %[[#C20]]
+  // CHECK3:       } // end sil function '$s3outyycfU1_5test3L_yS2f_S2ftFTJrSSSpSr'
+
+  // CHECK3-NONE:  {{^}}// pullback of test3 #1 (_:_:_:)
+  // CHECK3:       {{^}}// specialized pullback of test3 #1 (_:_:_:)
+  // CHECK3:       sil private @$s3outyycfU1_5test3L_yS2f_S2ftFTJpSSSpSr62$s16_Differentiation7_vjpSinySf5value_S2fc8pullbacktSfFS2fcfU_Sf0c1_d1_e4Cosyg1_hiJ2U_Sf025$sSf16_DifferentiationE7_e11Add3lhs3rhsg1_i17_SftSfc8pullbackti1_q5FZSf_Q6SfcfU_0c1_d1_e4Tanyg1_hiJ2U_Sf0lm1_n4E12_e16Subtract3lhs3rhsg1_i1_qri1_qs1_qT2U_Tf1nccccc_n : $@convention(thin) (Float, Float, Float, Float) -> (Float, Float, Float) {
+
+  @differentiable(reverse)
+  func test3(_ x: Float, _ y: Float, _ z: Float) -> Float {
+    return sin(x) + cos(y) - tan(z)
+  }
+
+  for x in -5...5 {
+    for y in -5...5 {
+      for z in -5...5 {
+        let pb = pullback(at: Float(x), Float(y), Float(z), of: test3)
+        let (der1, der2, der3) = pb(1)
+        expectEqual((10000 * der1).rounded(), (10000 * cos(Float(x))).rounded())
+        expectEqual((10000 * der2).rounded(), (10000 * (-sin(Float(y)))).rounded())
+        expectEqual((10000 * der3).rounded(), (10000 * (-(tan(Float(z)) * tan(Float(z)) + 1))).rounded())
+      }
+    }
+  }
+}
+
+runAllTests()
diff --git a/test/AutoDiff/validation-test/closure_specialization/single_bb2.swift b/test/AutoDiff/validation-test/closure_specialization/single_bb2.swift
new file mode 100644
index 0000000000000..2989dec84f31a
--- /dev/null
+++ b/test/AutoDiff/validation-test/closure_specialization/single_bb2.swift
@@ -0,0 +1,90 @@
+/// Single basic block VJP.
+
+// REQUIRES: executable_test
+
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -o %t/none.out -Onone
+// RUN: %target-build-swift %s -o %t/opt.out  -O
+// RUN: %target-codesign %t/none.out
+// RUN: %target-codesign %t/opt.out
+// RUN: %target-run %t/none.out
+// RUN: %target-run %t/opt.out
+
+// RUN: %target-swift-frontend -emit-sil %s -O -o %t/out.sil
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK4
+// RUN: cat %t/out.sil | %FileCheck %s --check-prefix=CHECK5
+
+// TODO: re-enable this test once we have OSSA throughout the pipeline
+// XFAIL: *
+
+import DifferentiationUnittest
+import StdlibUnittest
+
+var AutoDiffClosureSpecSingleBBTests = TestSuite("AutoDiffClosureSpecSingleBB")
+
+AutoDiffClosureSpecSingleBBTests.testWithLeakChecking("Test4") {
+  func square(_ x: Float) -> Float {
+    return x * x
+  }
+
+  func double(_ x: Float) -> Float {
+    return x + x
+  }
+
+  // CHECK4-LABEL: {{^}}// reverse-mode derivative of test4 #1 (_:)
+  // CHECK4-NEXT:  sil private @$s3outyycfU_5test4L_yS2fFTJrSpSr : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float) {
+  // CHECK4:         %[[#D9:]] = function_ref @$s3outyycfU_5test4L_yS2fFTJpSpSr128$s3outyycfU_6doubleL_yS2fFTJpSpSr067$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_Tf1nc_n0c12U_6squareL_yefg7Sr073$si1_j4E12_l16Multiply3lhs3rhsn1_o1_pq1_rs1_tu2U_eV2_nS2fTf1ncc_n : $@convention(thin) (Float, Float, Float) -> Float
+  // CHECK4:         %[[#D10:]] = partial_apply [callee_guaranteed] %[[#D9]](%[[#]], %[[#]]) : $@convention(thin) (Float, Float, Float) -> Float
+  // CHECK4:         %[[#D11:]] = tuple (%[[#]], %[[#D10]])
+  // CHECK4:         return %[[#D11]]
+  // CHECK4:       } // end sil function '$s3outyycfU_5test4L_yS2fFTJrSpSr'
+
+  // CHECK4-NONE:  {{^}}// pullback of test4 #1 (_:)
+  // CHECK4:       {{^}}// specialized pullback of test4 #1 (_:)
+  // CHECK4:       sil private @$s3outyycfU_5test4L_yS2fFTJpSpSr128$s3outyycfU_6doubleL_yS2fFTJpSpSr067$sSf16_DifferentiationE7_vjpAdd3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_Tf1nc_n0c12U_6squareL_yefg7Sr073$si1_j4E12_l16Multiply3lhs3rhsn1_o1_pq1_rs1_tu2U_eV2_nS2fTf1ncc_n : $@convention(thin) (Float, Float, Float) -> Float {
+
+  @differentiable(reverse)
+  func test4(_ x: Float) -> Float {
+    return square(double(x))
+  }
+
+  func test4Derivative(_ x: Float) -> Float {
+    return 8 * x
+  }
+
+  for x in -100...100 {
+    expectEqual(gradient(at: Float(x), of: test4), test4Derivative(Float(x)))
+  }
+}
+
+AutoDiffClosureSpecSingleBBTests.testWithLeakChecking("Test5") {
+  // CHECK5-LABEL: {{^}}// reverse-mode derivative of test5 #1 (_:_:)
+  // CHECK5-NEXT:  sil private @$s3outyycfU0_5test5L_ySaySfGAC_SftFTJrSSpSr : $@convention(thin) (@guaranteed Array<Float>, Float) -> (@owned Array<Float>, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, Float)) {
+  // CHECK5:         %[[#E79:]] = function_ref @$s3outyycfU0_5test5L_ySaySfGAC_SftFTJpSSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_S2f0cd1_ef1_g16Subtract3lhs3rhsi1_j1_klj1_km1_kN2U_Tf1ncncn_n : $@convention(thin) (@guaranteed Array<Float>.DifferentiableView, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), Float, Float) -> (@owned Array<Float>.DifferentiableView, Float)
+  // CHECK5:         %[[#E80:]] = partial_apply [callee_guaranteed] %[[#E79]](%[[#]], %[[#]], %[[#]], %[[#]]) : $@convention(thin) (@guaranteed Array<Float>.DifferentiableView, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), Float, Float) -> (@owned Array<Float>.DifferentiableView, Float)
+  // CHECK5:         %[[#E81:]] = tuple (%[[#]], %[[#E80]])
+  // CHECK5:         return %[[#E81]]
+  // CHECK5:       } // end sil function '$s3outyycfU0_5test5L_ySaySfGAC_SftFTJrSSpSr'
+
+  // CHECK5-NONE:  {{^}}// pullback of test5 #1 (_:_:)
+  // CHECK5:       {{^}}// specialized pullback of test5 #1 (_:_:)
+  // CHECK5:       sil private @$s3outyycfU0_5test5L_ySaySfGAC_SftFTJpSSpSr073$sSf16_DifferentiationE12_vjpMultiply3lhs3rhsSf5value_Sf_SftSfc8pullbacktj1_k5FZSf_K6SfcfU_S2f0cd1_ef1_g16Subtract3lhs3rhsi1_j1_klj1_km1_kN2U_Tf1ncncn_n : $@convention(thin) (@guaranteed Array<Float>.DifferentiableView, @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), @owned @callee_guaranteed (@guaranteed Array<Float>.DifferentiableView) -> (@owned Array<Float>.DifferentiableView, @owned Array<Float>.DifferentiableView), Float, Float) -> (@owned Array<Float>.DifferentiableView, Float) {
+
+  @differentiable(reverse)
+  func test5(_ x: [Float], _ y: Float) -> [Float] {
+    return [42 * y] + x + [37 - y]
+  }
+
+  let pb = pullback(at: [Float(1), Float(1)], Float(1), of: test5)
+  for a in -10...10 {
+    for b in -10...10 {
+      for c in -10...10 {
+        for d in -10...10 {
+          expectEqual(pb([Float(a), Float(b), Float(c), Float(d)]), ([Float(b), Float(c)], Float(42 * a - d)))
+        }
+      }
+    }
+  }
+}
+
+runAllTests()
diff --git a/test/AutoDiff/validation-test/control_flow.swift b/test/AutoDiff/validation-test/control_flow.swift
index 915049b0a5236..70f5260aa7310 100644
--- a/test/AutoDiff/validation-test/control_flow.swift
+++ b/test/AutoDiff/validation-test/control_flow.swift
@@ -628,12 +628,8 @@ ControlFlowTests.test("Loops") {
     } while i < 2
     return result
   }
-  // FIXME(TF-584): Investigate incorrect (too big) gradient values for
-  // repeat-while loops.
-  // expectEqual((8, 12), valueWithGradient(at: 2, of: repeat_while_loop))
-  // expectEqual((27, 27), valueWithGradient(at: 3, of: repeat_while_loop))
-  expectEqual((8, 18), valueWithGradient(at: 2, of: repeat_while_loop))
-  expectEqual((27, 36), valueWithGradient(at: 3, of: repeat_while_loop))
+  expectEqual((8, 12), valueWithGradient(at: 2, of: repeat_while_loop))
+  expectEqual((27, 27), valueWithGradient(at: 3, of: repeat_while_loop))
 
   func repeat_while_loop_nonactive_initial_value(_ x: Float) -> Float {
     var result: Float = 1
@@ -644,12 +640,87 @@ ControlFlowTests.test("Loops") {
     } while i < 2
     return result
   }
-  // FIXME(TF-584): Investigate incorrect (too big) gradient values for
-  // repeat-while loops.
-  // expectEqual((4, 4), valueWithGradient(at: 2, of: repeat_while_loop_nonactive_initial_value))
-  // expectEqual((9, 6), valueWithGradient(at: 3, of: repeat_while_loop_nonactive_initial_value))
-  expectEqual((4, 5), valueWithGradient(at: 2, of: repeat_while_loop_nonactive_initial_value))
-  expectEqual((9, 7), valueWithGradient(at: 3, of: repeat_while_loop_nonactive_initial_value))
+  expectEqual((4, 4), valueWithGradient(at: 2, of: repeat_while_loop_nonactive_initial_value))
+  expectEqual((9, 6), valueWithGradient(at: 3, of: repeat_while_loop_nonactive_initial_value))
+
+  @differentiable(reverse)
+  func repeat_while_loop_nested_repeat(_ x: Float) -> Float {
+    var result = x
+    var i = 0
+    repeat {
+      var temp = x
+      var j = 0
+      repeat {
+        temp = temp * x
+        j += 1
+      } while j < 2
+      result = result * temp
+      i += 1
+    } while i < 2
+    return result
+  }
+
+  expectEqual((128, 448), valueWithGradient(at: 2, of: repeat_while_loop_nested_repeat))
+  expectEqual((2187, 5103), valueWithGradient(at: 3, of: repeat_while_loop_nested_repeat))
+
+  @differentiable(reverse)
+  func repeat_while_loop_nested_while(_ x: Float) -> Float {
+    var result = x
+    var i = 0
+    repeat {
+      var temp = x
+      var j = 0
+      while j < 2 {
+        temp = temp * x
+        j += 1
+      }
+      result = result * temp
+      i += 1
+    } while i < 2
+    return result
+  }
+
+  expectEqual((128, 448), valueWithGradient(at: 2, of: repeat_while_loop_nested_while))
+  expectEqual((2187, 5103), valueWithGradient(at: 3, of: repeat_while_loop_nested_while))
+
+  @differentiable(reverse)
+  func repeat_while_loop_nested_for(_ x: Float) -> Float {
+    var result = x
+    var i = 0
+    repeat {
+      var temp = x
+      for j in 0..<2 {
+        temp = temp * x
+      }
+      result = result * temp
+      i += 1
+    } while i < 2
+    return result
+  }
+
+  expectEqual((128, 448), valueWithGradient(at: 2, of: repeat_while_loop_nested_for))
+  expectEqual((2187, 5103), valueWithGradient(at: 3, of: repeat_while_loop_nested_for))
+
+  @differentiable(reverse)
+  func repeat_while_loop_condition(_ x: Float) -> Float {
+    var result = x
+    var i = 0
+    repeat {
+      if i == 2 {
+        break
+      }
+      if i == 0 {
+        result = result * x
+      } else {
+        result = result * result
+      }
+      i += 1
+    } while i < 10
+    return result
+  }
+
+  expectEqual((16, 32), valueWithGradient(at: 2, of: repeat_while_loop_condition))
+  expectEqual((81, 108), valueWithGradient(at: 3, of: repeat_while_loop_condition))
 
   func loop_continue(_ x: Float) -> Float {
     var result = x
diff --git a/test/AutoDiff/validation-test/property_wrappers.swift b/test/AutoDiff/validation-test/property_wrappers.swift
index 4f102acc5d8c6..e28f6af997158 100644
--- a/test/AutoDiff/validation-test/property_wrappers.swift
+++ b/test/AutoDiff/validation-test/property_wrappers.swift
@@ -19,6 +19,7 @@ struct Wrapper<Value> {
   var wrappedValue: Value { // computed property
     get { value }
     set { value = newValue }
+    _modify { yield &value }
   }
 
   init(wrappedValue: Value) {
@@ -46,8 +47,6 @@ PropertyWrapperTests.test("SimpleStruct") {
   expectEqual((.init(x: 60, y: 0, z: 20), 300),
               gradient(at: Struct(), 2, of: setter))
 
-  // TODO: Support `modify` accessors (https://github.com/apple/swift/issues/55084).
-  /*
   func modify(_ s: Struct, _ x: Tracked<Float>) -> Tracked<Float> {
     var s = s
     s.x *= x * s.z
@@ -55,7 +54,6 @@ PropertyWrapperTests.test("SimpleStruct") {
   }
   expectEqual((.init(x: 60, y: 0, z: 20), 300),
               gradient(at: Struct(), 2, of: modify))
-  */
 }
 
 struct GenericStruct<T> {
@@ -86,8 +84,6 @@ PropertyWrapperTests.test("GenericStruct") {
   expectEqual((.init(x: 60, y: 0, z: 20), 300),
               gradient(at: GenericStruct<Tracked<Float>>(y: 20), 2, of: setter))
 
-  // TODO: Support `modify` accessors (https://github.com/apple/swift/issues/55084).
-  /*
   func modify<T>(_ s: GenericStruct<T>, _ x: Tracked<Float>) -> Tracked<Float> {
     var s = s
     s.x *= x * s.z
@@ -95,7 +91,6 @@ PropertyWrapperTests.test("GenericStruct") {
   }
   expectEqual((.init(x: 60, y: 0, z: 20), 300),
               gradient(at: GenericStruct<Tracked<Float>>(y: 1), 2, of: modify))
-  */
 }
 
 // TF-1149: Test class with loadable type but address-only `TangentVector` type.
@@ -131,16 +126,18 @@ PropertyWrapperTests.test("SimpleClass") {
               gradient(at: Class(), 2, of: setter))
   */
 
-  // TODO: Support `modify` accessors (https://github.com/apple/swift/issues/55084).
-  /*
+  // FIXME(TF-1175): Same issue as above
   func modify(_ c: Class, _ x: Tracked<Float>) -> Tracked<Float> {
     var c = c
     c.x *= x * c.z
     return c.x
   }
+  /*
   expectEqual((.init(x: 60, y: 0, z: 20), 300),
               gradient(at: Class(), 2, of: modify))
   */
+  expectEqual((.init(x: 1, y: 0, z: 0), 0),
+              gradient(at: Class(), 2, of: modify))
 }
 
 // From: https://github.com/apple/swift-evolution/blob/master/proposals/0258-property-wrappers.md#proposed-solution
@@ -157,12 +154,13 @@ enum Lazy<Value> {
 
   var wrappedValue: Value {
     // TODO(TF-1250): Replace with actual mutating getter implementation.
-    // Requires differentiation to support functions with multiple results.
-    get {
+    // Requires support for mutating semantic member accessor
+    /* mutating */ get {
       switch self {
       case .uninitialized(let initializer):
         let value = initializer()
         // NOTE: Actual implementation assigns to `self` here.
+        // self = .initialized(value)
         return value
       case .initialized(let value):
         return value
diff --git a/test/Sema/Inputs/availability_enum_case_other.swift b/test/Availability/Inputs/availability_enum_case_other.swift
similarity index 100%
rename from test/Sema/Inputs/availability_enum_case_other.swift
rename to test/Availability/Inputs/availability_enum_case_other.swift
diff --git a/test/Sema/Inputs/availability_multi_other.swift b/test/Availability/Inputs/availability_multi_other.swift
similarity index 100%
rename from test/Sema/Inputs/availability_multi_other.swift
rename to test/Availability/Inputs/availability_multi_other.swift
diff --git a/test/Sema/Inputs/conformance_availability_overlapping_other.swift b/test/Availability/Inputs/conformance_availability_overlapping_other.swift
similarity index 100%
rename from test/Sema/Inputs/conformance_availability_overlapping_other.swift
rename to test/Availability/Inputs/conformance_availability_overlapping_other.swift
diff --git a/test/Sema/api-availability-only.swift b/test/Availability/api-availability-only.swift
similarity index 100%
rename from test/Sema/api-availability-only.swift
rename to test/Availability/api-availability-only.swift
diff --git a/test/Availability/availability.swift b/test/Availability/availability.swift
new file mode 100644
index 0000000000000..1035cc9f9274d
--- /dev/null
+++ b/test/Availability/availability.swift
@@ -0,0 +1,175 @@
+// RUN: %target-typecheck-verify-swift -parse-as-library -module-name MyModule
+
+@available(*, unavailable)
+func unavailable_foo() {} // expected-note {{'unavailable_foo()' has been explicitly marked unavailable here}}
+
+@_unavailableInEmbedded // no-op without -enable-experimental-feature Embedded
+public func unavailable_in_embedded() { }
+
+func test() {
+  unavailable_foo() // expected-error {{'unavailable_foo()' is unavailable}}
+  unavailable_in_embedded() // ok
+}
+
+@available(*,unavailable,message: "use 'Int' instead")
+struct NSUInteger {} // expected-note 3 {{explicitly marked unavailable here}}
+
+struct Outer {
+  @available(*,unavailable,message: "use 'UInt' instead")
+  struct NSUInteger {} // expected-note 2 {{explicitly marked unavailable here}}
+}
+
+func foo(x : NSUInteger) { // expected-error {{'NSUInteger' is unavailable: use 'Int' instead}}
+     let y : NSUInteger = 42 // expected-error {{'NSUInteger' is unavailable: use 'Int' instead}}
+     // expected-error@-1 {{cannot convert value of type 'Int' to specified type 'NSUInteger'}}
+
+  let z : MyModule.NSUInteger = 42 // expected-error {{'NSUInteger' is unavailable: use 'Int' instead}}
+  // expected-error@-1 {{cannot convert value of type 'Int' to specified type 'NSUInteger'}}
+
+  let z2 : Outer.NSUInteger = 42 // expected-error {{'NSUInteger' is unavailable: use 'UInt' instead}}
+  // expected-error@-1 {{cannot convert value of type 'Int' to specified type 'Outer.NSUInteger'}}
+
+  let z3 : MyModule.Outer.NSUInteger = 42 // expected-error {{'NSUInteger' is unavailable: use 'UInt' instead}}
+  // expected-error@-1 {{cannot convert value of type 'Int' to specified type 'Outer.NSUInteger'}}
+}
+
+struct VarToFunc {
+  @available(*, unavailable, renamed: "function()")
+  var variable: Int { // expected-note 2 {{explicitly marked unavailable here}}
+    get { 0 }
+    set {}
+  }
+
+  @available(*, unavailable, renamed: "function()")
+  func oldFunction() -> Int { return 42 } // expected-note 2 {{explicitly marked unavailable here}}
+
+  func function() -> Int {
+    _ = variable // expected-error{{'variable' has been renamed to 'function()'}}{{9-17=function()}}
+    _ = oldFunction() //expected-error{{'oldFunction()' has been renamed to 'function()'}}{{9-20=function}}
+    _ = oldFunction // expected-error{{'oldFunction()' has been renamed to 'function()'}} {{9-20=function}}
+
+    return 42
+  }
+
+  mutating func testAssignment() {
+    // This is nonsense, but someone shouldn't be using 'renamed' for this
+    // anyway. Just make sure we don't crash or anything.
+    variable = 2 // expected-error {{'variable' has been renamed to 'function()'}} {{5-13=function()}}
+  }
+}
+
+struct DeferBody {
+  func foo() {
+    enum No: Error {
+      case no
+    }
+
+    defer {
+      do {
+        throw No.no
+      } catch No.no {
+      } catch {
+      }
+    }
+    _ = ()
+  }
+
+  func bar() {
+    @available(*, unavailable)
+    enum No: Error { // expected-note 2 {{'No' has been explicitly marked unavailable here}}
+      case no
+    }
+    do {
+      throw No.no
+      // expected-error@-1 {{'No' is unavailable}}
+    } catch No.no {} catch _ {}
+    // expected-error@-1 {{'No' is unavailable}}
+  }
+}
+
+// Ensure that we do not select the unavailable failable init as the
+// only solution and then fail to typecheck.
+protocol P {}
+
+class C : P {
+  @available(swift, obsoleted: 4)
+  public init?(_ c: C) {
+  }
+
+  public init<T : P>(_ c: T) {}
+}
+
+func f(c: C) {
+  let _: C? = C(c)
+}
+
+// rdar://problem/60047439 - unable to disambiguate expression based on availability
+func test_contextual_member_with_availability() {
+  struct A {
+    static var foo: A = A()
+  }
+
+  struct B {
+    @available(*, unavailable, renamed: "bar")
+    static var foo: B = B()
+  }
+
+  struct Test {
+    init(_: A) {}
+    init(_: B) {}
+  }
+
+  _ = Test(.foo) // Ok
+}
+
+@available(*, unavailable)
+func unavailableFunction(_ x: Int) -> Bool { true } // expected-note {{'unavailableFunction' has been explicitly marked unavailable here}}
+
+/// https://github.com/apple/swift/issues/55700
+/// Availability checking not working in the `where` clause of a `for` loop
+func f_55700(_ arr: [Int]) {
+  for x in arr where unavailableFunction(x) {} // expected-error {{'unavailableFunction' is unavailable}}
+}
+
+// rdar://101814209
+public struct Box<T> {
+  @usableFromInline
+  let value: T
+}
+
+@available(macOS, unavailable)
+extension Box where T == Int {
+  @usableFromInline
+  init(value: T) {
+    self.value = value
+  }
+}
+
+@available(macOS, unavailable)
+@_alwaysEmitIntoClient public func aeicFunction() {
+  // Select the unavailable @usableFromInline init over the synthesized internal
+  // memberwise initializer.
+  _ = Box(value: 42)
+}
+
+// rdar://87403752 - ambiguity with member declared in unavailable extension
+struct HasUnavailableExtesion {
+}
+
+@available(*, unavailable)
+extension HasUnavailableExtesion {
+  static var foo: Self = HasUnavailableExtesion()
+}
+
+func test_contextual_member_with_unavailable_extension() {
+  struct A {
+    static var foo: A = A()
+  }
+
+  struct Test {
+    init(_: A) {}
+    init(_: HasUnavailableExtesion) {}
+  }
+
+  _ = Test(.foo) // Ok `A.foo` since `foo` from `HasUnavailableExtesion` is unavailable
+}
diff --git a/test/Sema/availability_accessors.swift b/test/Availability/availability_accessors.swift
similarity index 84%
rename from test/Sema/availability_accessors.swift
rename to test/Availability/availability_accessors.swift
index 178e1492eb255..37d29f619b544 100644
--- a/test/Sema/availability_accessors.swift
+++ b/test/Availability/availability_accessors.swift
@@ -56,21 +56,33 @@ struct BaseStruct<T> {
 
   var unavailableGetter: T {
     @available(*, unavailable)
-    get { fatalError() } // expected-note 67 {{getter for 'unavailableGetter' has been explicitly marked unavailable here}}
-    set {}
+    get { fatalError() } // expected-note 73 {{getter for 'unavailableGetter' has been explicitly marked unavailable here}}
+    set { }
   }
 
   var unavailableSetter: T {
     get { fatalError() }
     @available(*, unavailable)
-    set { fatalError() } // expected-note 38 {{setter for 'unavailableSetter' has been explicitly marked unavailable here}}
+    set { fatalError() } // expected-note 33 {{setter for 'unavailableSetter' has been explicitly marked unavailable here}}
   }
 
   var unavailableGetterAndSetter: T {
     @available(*, unavailable)
-    get { fatalError() } // expected-note 67 {{getter for 'unavailableGetterAndSetter' has been explicitly marked unavailable here}}
+    get { fatalError() } // expected-note 71 {{getter for 'unavailableGetterAndSetter' has been explicitly marked unavailable here}}
     @available(*, unavailable)
-    set { fatalError() } // expected-note 38 {{setter for 'unavailableGetterAndSetter' has been explicitly marked unavailable here}}
+    set { fatalError() } // expected-note 33 {{setter for 'unavailableGetterAndSetter' has been explicitly marked unavailable here}}
+  }
+
+  var deprecatedGetter: T {
+    @available(*, deprecated, message: "reading not recommended")
+    get { fatalError() }
+    set { }
+  }
+
+  var deprecatedSetter: T {
+    get { fatalError() }
+    @available(*, deprecated, message: "writing not recommended")
+    set { }
   }
 }
 
@@ -233,7 +245,7 @@ func testSubscripts(_ s: BaseStruct<StructValue>) {
   _ = x.unavailableGetterAndSetter[available: s.available] // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}}
 }
 
-func testDiscardedKeyPathLoads_Struct() {
+func testDiscardedKeyPathApplicationLoads_Struct() {
   let a = [0]
   var x = BaseStruct<StructValue>()
 
@@ -266,7 +278,7 @@ func testDiscardedKeyPathLoads_Struct() {
   _ = a[keyPath: \.[takesInOut(&x.unavailableGetterAndSetter[0].b)]] // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}} expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
 }
 
-func testDiscardedKeyPathLoads_Class() {
+func testDiscardedKeyPathApplicationLoads_Class() {
   let a = [0]
   var x = BaseStruct<ClassValue>() // expected-warning {{variable 'x' was never mutated; consider changing to 'let' constant}}
 
@@ -299,7 +311,7 @@ func testDiscardedKeyPathLoads_Class() {
   _ = a[keyPath: \.[takesInOut(&x.unavailableGetterAndSetter[0].b)]] // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}}
 }
 
-func testKeyPathAssignments_Struct(_ someValue: StructValue) {
+func testKeyPathApplicationAssignments_Struct(_ someValue: StructValue) {
   var a = [0]
   var x = BaseStruct<StructValue>()
 
@@ -318,22 +330,22 @@ func testKeyPathAssignments_Struct(_ someValue: StructValue) {
   a[keyPath: \.[takesInOut(&x.unavailableGetter.a.b)]] = 0 // expected-error {{getter for 'unavailableGetter' is unavailable}}
   a[keyPath: \.[takesInOut(&x.unavailableGetter[0].b)]] = 0 // expected-error {{getter for 'unavailableGetter' is unavailable}}
 
-  x[keyPath: \.unavailableSetter] = someValue // expected-error {{setter for 'unavailableSetter' is unavailable}}
-  x[keyPath: \.unavailableSetter.a] = someValue.a // expected-error {{setter for 'unavailableSetter' is unavailable}}
-  x[keyPath: \.unavailableSetter[0]] = someValue.a // expected-error {{setter for 'unavailableSetter' is unavailable}}
-  x[keyPath: \.unavailableSetter[0].b] = 1 // expected-error {{setter for 'unavailableSetter' is unavailable}}
+  x[keyPath: \.unavailableSetter] = someValue // expected-error {{cannot assign through subscript: key path is read-only}}
+  x[keyPath: \.unavailableSetter.a] = someValue.a // expected-error {{cannot assign through subscript: key path is read-only}}
+  x[keyPath: \.unavailableSetter[0]] = someValue.a // expected-error {{cannot assign through subscript: key path is read-only}}
+  x[keyPath: \.unavailableSetter[0].b] = 1 // expected-error {{cannot assign through subscript: key path is read-only}}
   a[keyPath: \.[takesInOut(&x.unavailableSetter.a.b)]] = 0 // expected-error {{setter for 'unavailableSetter' is unavailable}}
   a[keyPath: \.[takesInOut(&x.unavailableSetter[0].b)]] = 0 // expected-error {{setter for 'unavailableSetter' is unavailable}}
 
-  x[keyPath: \.unavailableGetterAndSetter] = someValue // expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
-  x[keyPath: \.unavailableGetterAndSetter.a] = someValue.a // expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
-  x[keyPath: \.unavailableGetterAndSetter[0]] = someValue.a // expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
-  x[keyPath: \.unavailableGetterAndSetter[0].b] = 1 // expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
+  x[keyPath: \.unavailableGetterAndSetter] = someValue // expected-error {{cannot assign through subscript: key path is read-only}}
+  x[keyPath: \.unavailableGetterAndSetter.a] = someValue.a // expected-error {{cannot assign through subscript: key path is read-only}}
+  x[keyPath: \.unavailableGetterAndSetter[0]] = someValue.a // expected-error {{cannot assign through subscript: key path is read-only}}
+  x[keyPath: \.unavailableGetterAndSetter[0].b] = 1 // expected-error {{cannot assign through subscript: key path is read-only}}
   a[keyPath: \.[takesInOut(&x.unavailableGetterAndSetter.a.b)]] = 0 // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}} expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
   a[keyPath: \.[takesInOut(&x.unavailableGetterAndSetter[0].b)]] = 0 // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}} expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
 }
 
-func testKeyPathAssignments_Class(_ someValue: ClassValue) {
+func testKeyPathApplicationAssignments_Class(_ someValue: ClassValue) {
   var a = [0]
   var x = BaseStruct<ClassValue>()
 
@@ -352,7 +364,7 @@ func testKeyPathAssignments_Class(_ someValue: ClassValue) {
   a[keyPath: \.[takesInOut(&x.unavailableGetter.a.b)]] = 0 // expected-error {{getter for 'unavailableGetter' is unavailable}}
   a[keyPath: \.[takesInOut(&x.unavailableGetter[0].b)]] = 0 // expected-error {{getter for 'unavailableGetter' is unavailable}}
 
-  x[keyPath: \.unavailableSetter] = someValue // expected-error {{setter for 'unavailableSetter' is unavailable}}
+  x[keyPath: \.unavailableSetter] = someValue // expected-error {{cannot assign through subscript: key path is read-only}}
   // FIXME: spurious unavailable setter error
   x[keyPath: \.unavailableSetter.a] = someValue.a // expected-error {{setter for 'unavailableSetter' is unavailable}}
   // FIXME: spurious unavailable setter error
@@ -362,7 +374,7 @@ func testKeyPathAssignments_Class(_ someValue: ClassValue) {
   a[keyPath: \.[takesInOut(&x.unavailableSetter.a.b)]] = 0
   a[keyPath: \.[takesInOut(&x.unavailableSetter[0].b)]] = 0
 
-  x[keyPath: \.unavailableGetterAndSetter] = someValue // expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
+  x[keyPath: \.unavailableGetterAndSetter] = someValue // expected-error {{cannot assign through subscript: key path is read-only}}
   x[keyPath: \.unavailableGetterAndSetter.a] = someValue.a // expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
   x[keyPath: \.unavailableGetterAndSetter[0]] = someValue.a // expected-error {{setter for 'unavailableGetterAndSetter' is unavailable}}
   // FIXME: spurious unavailable setter error
@@ -528,6 +540,67 @@ func testDiscardedApplyOfFuncWithInOutParam_Class() {
   _ = takesInOut(&x.unavailableGetterAndSetter[0].b).magnitude // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}}
 }
 
+func testKeyPathArguments_Struct() {
+  var x = BaseStruct<StructValue>()
+
+  func takesKeyPath<T, U>(_ t: T, _ keyPath: KeyPath<T, U>) -> () { }
+
+  takesKeyPath(x, \.available)
+  takesKeyPath(x, \.unavailableGetter) // expected-error {{getter for 'unavailableGetter' is unavailable}}
+  takesKeyPath(x, \.unavailableSetter)
+  takesKeyPath(x, \.unavailableGetterAndSetter) // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}}
+  takesKeyPath(x, \.deprecatedGetter) // expected-warning {{getter for 'deprecatedGetter' is deprecated: reading not recommended}}
+  takesKeyPath(x, \.deprecatedSetter)
+
+  func takesAnyKeyPath(_ keyPath: AnyKeyPath) -> () { }
+
+  takesAnyKeyPath(\BaseStruct<StructValue>.available)
+  takesAnyKeyPath(\BaseStruct<StructValue>.unavailableGetter) // expected-error {{getter for 'unavailableGetter' is unavailable}}
+  takesAnyKeyPath(\BaseStruct<StructValue>.unavailableSetter)
+  takesAnyKeyPath(\BaseStruct<StructValue>.unavailableGetterAndSetter) // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}}
+  takesAnyKeyPath(\BaseStruct<StructValue>.deprecatedGetter) // expected-warning {{getter for 'deprecatedGetter' is deprecated: reading not recommended}}
+  takesAnyKeyPath(\BaseStruct<StructValue>.deprecatedSetter)
+
+  func takesPartialKeyPath<T>(_ t: T, _ keyPath: PartialKeyPath<T>) -> () { }
+  takesPartialKeyPath(x, \.available)
+  takesPartialKeyPath(x, \.unavailableGetter) // expected-error {{getter for 'unavailableGetter' is unavailable}}
+  takesPartialKeyPath(x, \.unavailableSetter)
+  takesPartialKeyPath(x, \.unavailableGetterAndSetter) // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}}
+  takesPartialKeyPath(x, \.deprecatedGetter) // expected-warning {{getter for 'deprecatedGetter' is deprecated: reading not recommended}}
+  takesPartialKeyPath(x, \.deprecatedSetter)
+
+  func takesSendableKeyPath<T, U>(_ t: T, _ keyPath: KeyPath<T, U> & Sendable) -> () { }
+
+  takesSendableKeyPath(x, \.available)
+  takesSendableKeyPath(x, \.unavailableGetter) // expected-error {{getter for 'unavailableGetter' is unavailable}}
+  takesSendableKeyPath(x, \.unavailableSetter)
+  takesSendableKeyPath(x, \.unavailableGetterAndSetter) // expected-error {{getter for 'unavailableGetterAndSetter' is unavailable}}
+  takesSendableKeyPath(x, \.deprecatedGetter) // expected-warning {{getter for 'deprecatedGetter' is deprecated: reading not recommended}}
+  takesSendableKeyPath(x, \.deprecatedSetter)
+
+  func takesWritableKeyPath<T, U>(_ t: inout T, _ keyPath: WritableKeyPath<T, U>) -> () { }
+  // expected-note@-1 2 {{in call to function 'takesWritableKeyPath'}}
+
+  takesWritableKeyPath(&x, \.available)
+  takesWritableKeyPath(&x, \.unavailableGetter) // expected-error {{getter for 'unavailableGetter' is unavailable}}
+  // FIXME: Ideally we would diagnose the unavailability of the setter instead
+  // of simply indicating that a conversion to WritableKeyPath is not possible
+  // (rdar://157249275)
+  takesWritableKeyPath(&x, \.unavailableSetter) // expected-error {{cannot convert value of type 'KeyPath<BaseStruct<StructValue>, StructValue>' to expected argument type 'WritableKeyPath<BaseStruct<StructValue>, U>'}}
+  // expected-error@-1 {{generic parameter 'U' could not be inferred}}
+  takesWritableKeyPath(&x, \.unavailableGetterAndSetter) // expected-error {{cannot convert value of type 'KeyPath<BaseStruct<StructValue>, StructValue>' to expected argument type 'WritableKeyPath<BaseStruct<StructValue>, U>'}}
+  // expected-error@-1 {{generic parameter 'U' could not be inferred}}
+  takesWritableKeyPath(&x, \.deprecatedGetter) // expected-warning {{getter for 'deprecatedGetter' is deprecated: reading not recommended}}
+  takesWritableKeyPath(&x, \.deprecatedSetter) // expected-warning {{setter for 'deprecatedSetter' is deprecated: writing not recommended}}
+
+  func takesUnifiedTypes<T>(_: T, _: T) { }
+
+  takesUnifiedTypes(\BaseStruct<StructValue>.available, \BaseStruct<StructValue>.available)
+  takesUnifiedTypes(\BaseStruct<StructValue>.available, \BaseStruct<StructValue>.unavailableGetter) // expected-error {{getter for 'unavailableGetter' is unavailable}}
+  takesUnifiedTypes(\BaseStruct<StructValue>.available, \BaseStruct<StructValue>.unavailableSetter)
+  takesUnifiedTypes(\BaseStruct<StructValue>.available, \BaseStruct<StructValue>.deprecatedSetter) // expected-warning {{setter for 'deprecatedSetter' is deprecated: writing not recommended}}
+  takesUnifiedTypes(\BaseStruct<StructValue>.unavailableSetter, \BaseStruct<StructValue>.deprecatedSetter)
+}
 
 var global = BaseStruct<StructValue>()
 
@@ -555,18 +628,18 @@ struct TestPatternBindingInitExprs {
 
 struct BadAccessorAvailability<T> {
   var alwaysUnavailableObservers: T  {
-    @available(*, unavailable) // expected-error {{willSet observer for property cannot be marked unavailable with '@available'}}
+    @available(*, unavailable) // expected-error {{willSet observer cannot be marked unavailable with '@available'}}
     willSet { }
 
-    @available(*, unavailable) // expected-error {{didSet observer for property cannot be marked unavailable with '@available'}}
+    @available(*, unavailable) // expected-error {{didSet observer cannot be marked unavailable with '@available'}}
     didSet { }
   }
 
   var observersUnavailableBeforeSwift99: T  {
-    @available(swift, introduced: 99) // expected-error {{willSet observer for property cannot be marked unavailable with '@available'}}
+    @available(swift, introduced: 99) // expected-error {{willSet observer cannot be marked unavailable with '@available'}}
     willSet { }
 
-    @available(swift, introduced: 99) // expected-error {{didSet observer for property cannot be marked unavailable with '@available'}}
+    @available(swift, introduced: 99) // expected-error {{didSet observer cannot be marked unavailable with '@available'}}
     didSet { }
   }
 }
diff --git a/test/Sema/availability_and_delayed_parsing.swift b/test/Availability/availability_and_delayed_parsing.swift
similarity index 100%
rename from test/Sema/availability_and_delayed_parsing.swift
rename to test/Availability/availability_and_delayed_parsing.swift
diff --git a/test/Sema/availability_compound.swift b/test/Availability/availability_compound.swift
similarity index 100%
rename from test/Sema/availability_compound.swift
rename to test/Availability/availability_compound.swift
diff --git a/test/Availability/availability_custom_domains.swift b/test/Availability/availability_custom_domains.swift
new file mode 100644
index 0000000000000..a30f5e38aadf3
--- /dev/null
+++ b/test/Availability/availability_custom_domains.swift
@@ -0,0 +1,570 @@
+// RUN: %target-typecheck-verify-swift \
+// RUN:  -enable-experimental-feature CustomAvailability \
+// RUN:  -define-enabled-availability-domain EnabledDomain \
+// RUN:  -define-always-enabled-availability-domain AlwaysEnabledDomain \
+// RUN:  -define-disabled-availability-domain DisabledDomain \
+// RUN:  -define-dynamic-availability-domain DynamicDomain
+
+// REQUIRES: swift_feature_CustomAvailability
+
+func alwaysAvailable() { }
+
+@available(EnabledDomain)
+func availableInEnabledDomain() { }
+
+@available(AlwaysEnabledDomain)
+func availableInAlwaysEnabledDomain() { }
+
+@available(EnabledDomain, unavailable)
+func unavailableInEnabledDomain() { } // expected-note * {{'unavailableInEnabledDomain()' has been explicitly marked unavailable here}}
+
+@available(AlwaysEnabledDomain, unavailable)
+func unavailableInAlwaysEnabledDomain() { } // expected-note * {{'unavailableInAlwaysEnabledDomain()' has been explicitly marked unavailable here}}
+
+@available(DisabledDomain, unavailable)
+func unavailableInDisabledDomain() { } // expected-note * {{'unavailableInDisabledDomain()' has been explicitly marked unavailable here}}
+
+@available(DynamicDomain)
+func availableInDynamicDomain() { }
+
+@available(DynamicDomain, deprecated, message: "Use something else")
+func deprecatedInDynamicDomain() { }
+
+@available(DynamicDomain, unavailable)
+func unavailableInDynamicDomain() { } // expected-note * {{'unavailableInDynamicDomain()' has been explicitly marked unavailable here}}
+
+@available(UnknownDomain) // expected-error {{unrecognized platform name 'UnknownDomain'}}
+func availableInUnknownDomain() { }
+
+@available(EnabledDomain)
+@available(EnabledDomain)
+func availableInEnabledDomainTwice() { }
+
+@available(EnabledDomain)
+@available(EnabledDomain, unavailable)
+func availableAndUnavailableInEnabledDomain() { } // expected-note {{'availableAndUnavailableInEnabledDomain()' has been explicitly marked unavailable here}}
+
+func testDeployment() { // expected-note 3 {{add '@available' attribute to enclosing global function}}
+  alwaysAvailable()
+  availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  availableInAlwaysEnabledDomain()
+  unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+  unavailableInAlwaysEnabledDomain() // expected-error {{'unavailableInAlwaysEnabledDomain()' is unavailable}}
+  unavailableInDisabledDomain() // expected-error {{'unavailableInDisabledDomain()' is unavailable}}
+  deprecatedInDynamicDomain() // expected-warning {{'deprecatedInDynamicDomain()' is deprecated: Use something else}}
+  unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
+  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  availableInUnknownDomain()
+  availableInEnabledDomainTwice() // expected-error {{'availableInEnabledDomainTwice()' is only available in EnabledDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  availableAndUnavailableInEnabledDomain() // expected-error {{'availableAndUnavailableInEnabledDomain()' is unavailable}}
+}
+
+// FIXME: [availability] Test @inlinable functions.
+
+func testIfAvailable(_ truthy: Bool) { // expected-note 9 {{add '@available' attribute to enclosing global function}}
+  if #available(EnabledDomain) { // expected-note {{enclosing scope here}}
+    availableInEnabledDomain()
+    availableInAlwaysEnabledDomain()
+    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+    unavailableInAlwaysEnabledDomain() // expected-error {{'unavailableInAlwaysEnabledDomain()' is unavailable}}
+    availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+    unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
+
+    if #available(DynamicDomain) {
+      availableInEnabledDomain()
+      unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+      availableInDynamicDomain()
+      unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
+    } else {
+      availableInEnabledDomain()
+      unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+      availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+      // expected-note@-1 {{add 'if #available' version check}}
+      unavailableInDynamicDomain()
+    }
+
+    if #available(EnabledDomain) {} // expected-warning {{unnecessary check for 'EnabledDomain'; enclosing scope ensures guard will always be true}}
+
+    if #unavailable(EnabledDomain) { // FIXME: [availability] Diagnose as unreachable
+      // Unreachable.
+      availableInEnabledDomain()
+      unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+      availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+      // expected-note@-1 {{add 'if #available' version check}}
+      unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
+    }
+  } else {
+    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+    unavailableInEnabledDomain()
+    availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+    unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
+  }
+
+  if #available(EnabledDomain), #available(DynamicDomain) {
+    availableInEnabledDomain()
+    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+    availableInDynamicDomain()
+    unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
+  } else {
+    // In this branch, we only know that one of the domains is unavailable,
+    // but we don't know which.
+    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+    availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+    unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
+  }
+
+  if #available(EnabledDomain), truthy {
+    availableInEnabledDomain()
+    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+  } else {
+    // In this branch, the state of EnabledDomain remains unknown since
+    // execution will reach here if "truthy" is false.
+    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+  }
+
+  if #unavailable(EnabledDomain) {
+    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+    unavailableInEnabledDomain()
+  } else {
+    availableInEnabledDomain()
+    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+  }
+
+  // FIXME: [availability] Support mixed #available and #unavailable.
+  if #unavailable(EnabledDomain), #available(DynamicDomain) {
+    // expected-error@-1 {{#available and #unavailable cannot be in the same statement}}
+  }
+
+  if #available(AlwaysEnabledDomain) {
+    availableInAlwaysEnabledDomain()
+    unavailableInAlwaysEnabledDomain() // expected-error {{'unavailableInAlwaysEnabledDomain()' is unavailable}}
+  } else {
+    availableInAlwaysEnabledDomain()
+    unavailableInAlwaysEnabledDomain()
+  }
+}
+
+func testWhileAvailable() { // expected-note {{add '@available' attribute to enclosing global function}}
+  while #available(EnabledDomain) { // expected-note {{enclosing scope here}}
+    availableInEnabledDomain()
+    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+
+    if #available(EnabledDomain) {} // expected-warning {{unnecessary check for 'EnabledDomain'; enclosing scope ensures guard will always be true}}
+    if #unavailable(EnabledDomain) {} // FIXME: [availability] Diagnose as unreachable
+  }
+
+  while #unavailable(EnabledDomain) {
+    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+    unavailableInEnabledDomain()
+
+    if #available(EnabledDomain) {} // FIXME: [availability] Diagnose as unreachable
+    if #unavailable(EnabledDomain) {} // FIXME: [availability] Diagnose as redundant
+  }
+}
+
+func testGuardAvailable() { // expected-note 3 {{add '@available' attribute to enclosing global function}}
+  guard #available(EnabledDomain) else { // expected-note {{enclosing scope here}}
+    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+    unavailableInEnabledDomain()
+    availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+    // expected-note@-1 {{add 'if #available' version check}}
+
+    return
+  }
+
+  availableInEnabledDomain()
+  unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}
+
+  if #available(EnabledDomain) {} // expected-warning {{unnecessary check for 'EnabledDomain'; enclosing scope ensures guard will always be true}}
+  if #unavailable(EnabledDomain) {} // FIXME: [availability] Diagnose as unreachable
+}
+
+@available(EnabledDomain)
+func testEnabledDomainAvailable() { // expected-note {{add '@available' attribute to enclosing global function}} expected-note {{enclosing scope here}}
+  availableInEnabledDomain()
+  unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
+
+  if #available(EnabledDomain) {} // expected-warning {{unnecessary check for 'EnabledDomain'; enclosing scope ensures guard will always be true}}
+  if #unavailable(EnabledDomain) {} // FIXME: [availability] Diagnose as unreachable
+
+  alwaysAvailable()
+  unavailableInDisabledDomain() // expected-error {{'unavailableInDisabledDomain()' is unavailable}}
+  deprecatedInDynamicDomain() // expected-warning {{'deprecatedInDynamicDomain()' is deprecated: Use something else}}
+  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  availableInUnknownDomain()
+}
+
+@available(EnabledDomain, unavailable)
+func testEnabledDomainUnavailable() { // expected-note {{add '@available' attribute to enclosing global function}}
+  availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  unavailableInEnabledDomain()
+
+  if #available(EnabledDomain) {} // FIXME: [availability] Diagnose as unreachable
+  if #unavailable(EnabledDomain) {} // FIXME: [availability] Diagnose as redundant
+
+  alwaysAvailable()
+  unavailableInDisabledDomain() // expected-error {{'unavailableInDisabledDomain()' is unavailable}}
+  deprecatedInDynamicDomain() // expected-warning {{'deprecatedInDynamicDomain()' is deprecated: Use something else}}
+  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  availableInUnknownDomain()
+}
+
+@available(AlwaysEnabledDomain)
+func testAlwaysEnabledDomainAvailable() {
+  availableInAlwaysEnabledDomain()
+  unavailableInAlwaysEnabledDomain() // expected-error {{'unavailableInAlwaysEnabledDomain()' is unavailable}}
+}
+
+@available(AlwaysEnabledDomain, unavailable)
+func testAlwaysEnabledDomainUnavailable() {
+  availableInAlwaysEnabledDomain()
+  unavailableInAlwaysEnabledDomain()
+}
+
+@available(*, unavailable)
+func testUniversallyUnavailable() {
+  alwaysAvailable()
+  // FIXME: [availability] Diagnostic consistency: potentially unavailable declaration shouldn't be diagnosed
+  // in contexts that are unavailable to broader domains
+  availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  unavailableInEnabledDomain()
+  availableInAlwaysEnabledDomain()
+  unavailableInAlwaysEnabledDomain()
+  unavailableInDisabledDomain()
+  deprecatedInDynamicDomain() // expected-warning {{'deprecatedInDynamicDomain()' is deprecated: Use something else}}
+  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  availableInUnknownDomain()
+
+  if #available(EnabledDomain) {} // FIXME: [availability] Diagnose?
+  if #unavailable(EnabledDomain) {} // FIXME: [availability] Diagnose?
+}
+
+@available(EnabledDomain)
+struct EnabledDomainAvailable {
+  @available(DynamicDomain)
+  func dynamicDomainAvailableMethod() {
+    availableInEnabledDomain()
+    availableInDynamicDomain()
+
+    alwaysAvailable()
+    unavailableInDisabledDomain() // expected-error {{'unavailableInDisabledDomain()' is unavailable}}
+  }
+}
+
+func testFixIts() {
+  // expected-note@-1 {{add '@available' attribute to enclosing global function}}{{1-1=@available(EnabledDomain)\n}}
+  availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
+  // expected-note@-1 {{add 'if #available' version check}}{{3-29=if #available(EnabledDomain) {\n      availableInEnabledDomain()\n  \} else {\n      // Fallback\n  \}}}
+}
+
+struct Container { }
+
+@available(EnabledDomain)
+extension Container {
+  @available(EnabledDomain)
+  func redundantlyAvailableInEnabledDomain() { }
+
+  @available(EnabledDomain, unavailable)
+  func unavailableInEnabledDomain() { }
+}
+
+protocol OpaqueReturnType { }
+
+@available(EnabledDomain)
+struct AvailableOpaqueReturnType: OpaqueReturnType { }
+
+@available(EnabledDomain, unavailable)
+struct UnavailableOpaqueReturnType: OpaqueReturnType { }
+
+func testOpaqueReturnType() -> some OpaqueReturnType {
+  if #available(EnabledDomain) { // expected-error {{opaque return type cannot depend on EnabledDomain availability}}
+    return AvailableOpaqueReturnType()
+  } else {
+    return UnavailableOpaqueReturnType()
+  }
+}
+
+protocol HasRequirementInEnabledDomain {
+  func alwaysAvailableRequirement()
+  // expected-note@-1 3 {{protocol requirement here}}
+  // expected-note@-2 {{requirement 'alwaysAvailableRequirement()' declared here}}
+
+  @available(EnabledDomain)
+  func availableInEnabledDomain()
+  // expected-note@-1 2 {{protocol requirement here}}
+  // expected-note@-2 {{requirement 'availableInEnabledDomain()' declared here}}
+}
+
+protocol HasAssocTypeRequirementInEnabledDomain {
+  associatedtype A // expected-note {{requirement 'A' declared here}}
+
+  @available(EnabledDomain)
+  associatedtype B // expected-note {{requirement 'B' declared here}}
+}
+
+protocol HasRequirementUnavailableInEnabledDomain {
+  @available(EnabledDomain, unavailable) // expected-error {{protocol members can only be marked unavailable in an '@objc' protocol}}
+  func unavailableInEnabledDomain()
+}
+
+struct ConformsToHasRequirementsInEnabledDomain: HasRequirementInEnabledDomain {
+  func alwaysAvailableRequirement() { }
+  func availableInEnabledDomain() { }
+}
+
+@available(EnabledDomain)
+struct ConformsToHasRequirementsInEnabledDomain1: HasRequirementInEnabledDomain {
+  func alwaysAvailableRequirement() { }
+  func availableInEnabledDomain() { }
+}
+
+@available(EnabledDomain, unavailable)
+struct ConformsToHasRequirementsInEnabledDomain2: HasRequirementInEnabledDomain {
+  func alwaysAvailableRequirement() { }
+  func availableInEnabledDomain() { }
+}
+
+struct ConformsToHasRequirementsInEnabledDomain3: HasRequirementInEnabledDomain {
+  @available(EnabledDomain)
+  func alwaysAvailableRequirement() { } // expected-error {{protocol 'HasRequirementInEnabledDomain' requirement 'alwaysAvailableRequirement()' cannot be satisfied by instance method that is only available in EnabledDomain}}
+  @available(EnabledDomain)
+  func availableInEnabledDomain() { }
+}
+
+struct ConformsToHasRequirementsInEnabledDomain4: HasRequirementInEnabledDomain { // expected-error {{type 'ConformsToHasRequirementsInEnabledDomain4' does not conform to protocol 'HasRequirementInEnabledDomain'}}
+  @available(EnabledDomain, unavailable)
+  func alwaysAvailableRequirement() { } // expected-error {{unavailable instance method 'alwaysAvailableRequirement()' was used to satisfy a requirement of protocol 'HasRequirementInEnabledDomain'}}
+  @available(EnabledDomain, unavailable)
+  func availableInEnabledDomain() { } // expected-error {{unavailable instance method 'availableInEnabledDomain()' was used to satisfy a requirement of protocol 'HasRequirementInEnabledDomain'}}
+}
+
+struct ConformsToHasRequirementsInEnabledDomain5: HasRequirementInEnabledDomain {
+  @available(DisabledDomain)
+  func alwaysAvailableRequirement() { } // expected-error {{protocol 'HasRequirementInEnabledDomain' requirement 'alwaysAvailableRequirement()' cannot be satisfied by instance method that is only available in DisabledDomain}}
+  @available(DisabledDomain)
+  func availableInEnabledDomain() { } // expected-error {{protocol 'HasRequirementInEnabledDomain' requirement 'availableInEnabledDomain()' cannot be satisfied by instance method that is only available in DisabledDomain}}
+}
+
+struct ConformsToHasRequirementsInEnabledDomain6: HasRequirementInEnabledDomain {
+  @available(EnabledDomain)
+  @available(DisabledDomain)
+  func alwaysAvailableRequirement() { } // expected-error {{protocol 'HasRequirementInEnabledDomain' requirement 'alwaysAvailableRequirement()' cannot be satisfied by instance method that is only available in DisabledDomain}}
+  @available(EnabledDomain)
+  @available(DisabledDomain)
+  func availableInEnabledDomain() { } // expected-error {{protocol 'HasRequirementInEnabledDomain' requirement 'availableInEnabledDomain()' cannot be satisfied by instance method that is only available in DisabledDomain}}
+}
+
+struct ConformsToHasAssocTypeRequirementInEnabledDomain: HasAssocTypeRequirementInEnabledDomain {
+  struct A { }
+  struct B { }
+}
+
+struct ConformsToHasAssocTypeRequirementInEnabledDomain1: HasAssocTypeRequirementInEnabledDomain { // expected-error {{type 'ConformsToHasAssocTypeRequirementInEnabledDomain1' does not conform to protocol 'HasAssocTypeRequirementInEnabledDomain'}}
+  @available(EnabledDomain)
+  struct A { } // expected-error {{protocol 'HasAssocTypeRequirementInEnabledDomain' requirement 'A' cannot be satisfied by struct that is only available in EnabledDomain}}
+
+  @available(EnabledDomain)
+  struct B { }
+}
+
+struct ConformsToHasAssocTypeRequirementInEnabledDomain2: HasAssocTypeRequirementInEnabledDomain { // expected-error {{type 'ConformsToHasAssocTypeRequirementInEnabledDomain2' does not conform to protocol 'HasAssocTypeRequirementInEnabledDomain'}}
+  @available(EnabledDomain, unavailable)
+  struct A { } // expected-error {{unavailable struct 'A' was used to satisfy a requirement of protocol 'HasAssocTypeRequirementInEnabledDomain'}}
+
+  @available(EnabledDomain, unavailable)
+  struct B { } // expected-error {{unavailable struct 'B' was used to satisfy a requirement of protocol 'HasAssocTypeRequirementInEnabledDomain'}}
+}
+
+struct ConformsToHasAssocTypeRequirementInEnabledDomain3: HasAssocTypeRequirementInEnabledDomain {  // expected-error {{type 'ConformsToHasAssocTypeRequirementInEnabledDomain3' does not conform to protocol 'HasAssocTypeRequirementInEnabledDomain'}}
+  @available(DisabledDomain)
+  struct A { } // expected-error {{protocol 'HasAssocTypeRequirementInEnabledDomain' requirement 'A' cannot be satisfied by struct that is only available in DisabledDomain}}
+
+  @available(DisabledDomain)
+  struct B { } // expected-error {{protocol 'HasAssocTypeRequirementInEnabledDomain' requirement 'B' cannot be satisfied by struct that is only available in DisabledDomain}}
+}
+
+class Base {
+  func alwaysAvailable() { }
+  // expected-note@-1 * {{overridden declaration is here}}
+
+  @available(EnabledDomain)
+  func availableInEnabledDomain() { }
+  // expected-note@-1 * {{overridden declaration is here}}
+
+  @available(EnabledDomain, unavailable)
+  func unavailableInEnabledDomain() { }
+  // expected-note@-1 * {{overridden declaration is here}}
+  // expected-note@-2 * {{'unavailableInEnabledDomain()' has been explicitly marked unavailable here}}
+}
+
+class Derived1: Base {
+  override func alwaysAvailable() { }
+
+  override func availableInEnabledDomain() { }
+
+  override func unavailableInEnabledDomain() { } // expected-error {{cannot override 'unavailableInEnabledDomain' which has been marked unavailable}}
+  // expected-note@-1 {{remove 'override' modifier to declare a new 'unavailableInEnabledDomain'}}
+}
+
+class Derived2: Base {
+  @available(EnabledDomain)
+  override func alwaysAvailable() { } // expected-error {{overriding 'alwaysAvailable' must be as available as declaration it overrides}}
+
+  @available(EnabledDomain)
+  override func availableInEnabledDomain() { }
+
+  @available(EnabledDomain)
+  override func unavailableInEnabledDomain() { } // expected-error {{overriding 'unavailableInEnabledDomain' must be as available as declaration it overrides}}
+}
+
+@available(EnabledDomain)
+class Derived3: Base {
+  override func alwaysAvailable() { }
+
+  override func availableInEnabledDomain() { }
+
+  override func unavailableInEnabledDomain() { } // expected-error {{cannot override 'unavailableInEnabledDomain' which has been marked unavailable}}
+  // expected-note@-1 {{remove 'override' modifier to declare a new 'unavailableInEnabledDomain'}}
+}
+
+@available(EnabledDomain)
+class Derived4: Base {
+  @available(EnabledDomain)
+  override func alwaysAvailable() { }
+
+  @available(EnabledDomain)
+  override func availableInEnabledDomain() { }
+
+  @available(EnabledDomain)
+  override func unavailableInEnabledDomain() { } // expected-error {{overriding 'unavailableInEnabledDomain' must be as available as declaration it overrides}}
+}
+
+class Derived5: Base {
+  @available(DisabledDomain)
+  override func alwaysAvailable() { } // expected-error {{overriding 'alwaysAvailable' must be as available as declaration it overrides}}
+
+  @available(DisabledDomain)
+  override func availableInEnabledDomain() { } // expected-error {{overriding 'availableInEnabledDomain' must be as available as declaration it overrides}}
+
+  @available(DisabledDomain)
+  override func unavailableInEnabledDomain() { } // expected-error {{overriding 'unavailableInEnabledDomain' must be as available as declaration it overrides}}
+}
+
+@available(DisabledDomain)
+class Derived6: Base {
+  override func alwaysAvailable() { }
+
+  override func availableInEnabledDomain() { }
+
+  override func unavailableInEnabledDomain() { } // expected-error {{cannot override 'unavailableInEnabledDomain' which has been marked unavailable}}
+  // expected-note@-1 {{remove 'override' modifier to declare a new 'unavailableInEnabledDomain'}}
+}
+
+@available(DisabledDomain)
+class Derived7: Base {
+  @available(DisabledDomain)
+  override func alwaysAvailable() { }
+
+  @available(DisabledDomain)
+  override func availableInEnabledDomain() { }
+
+  @available(DisabledDomain)
+  override func unavailableInEnabledDomain() { } // expected-error {{cannot override 'unavailableInEnabledDomain' which has been marked unavailable}}
+  // expected-note@-1 {{remove 'override' modifier to declare a new 'unavailableInEnabledDomain'}}
+}
+
+class Derived8: Base {
+  @available(EnabledDomain, unavailable)
+  override func alwaysAvailable() { } // expected-error {{cannot override 'alwaysAvailable' with a declaration that is marked unavailable}}
+
+  @available(EnabledDomain, unavailable)
+  override func availableInEnabledDomain() { } // expected-error {{cannot override 'availableInEnabledDomain' with a declaration that is marked unavailable}}
+
+  @available(EnabledDomain, unavailable)
+  override func unavailableInEnabledDomain() { }
+}
+
+@available(EnabledDomain, unavailable)
+class Derived9: Base {
+  override func alwaysAvailable() { }
+
+  override func availableInEnabledDomain() { }
+
+  override func unavailableInEnabledDomain() { }
+}
+
+@available(EnabledDomain, unavailable)
+class Derived10: Base {
+  @available(EnabledDomain, unavailable)
+  override func alwaysAvailable() { }
+
+  @available(EnabledDomain, unavailable)
+  override func availableInEnabledDomain() { }
+
+  @available(EnabledDomain, unavailable)
+  override func unavailableInEnabledDomain() { }
+}
+
+@available(EnabledDomain, unavailable)
+class Derived11: Base {
+  @available(EnabledDomain)
+  override func alwaysAvailable() { } // expected-error {{overriding 'alwaysAvailable' must be as available as declaration it overrides}}
+
+  @available(EnabledDomain)
+  override func availableInEnabledDomain() { } // expected-error {{overriding 'availableInEnabledDomain' must be as available as declaration it overrides}}
+
+  @available(EnabledDomain)
+  override func unavailableInEnabledDomain() { } // expected-error {{overriding 'unavailableInEnabledDomain' must be as available as declaration it overrides}}
+}
+
+@available(EnabledDomain)
+class BaseAvailableInEnabledDomain { }
+
+class DerivedMoreAvailable: BaseAvailableInEnabledDomain { // expected-error {{'BaseAvailableInEnabledDomain' is only available in EnabledDomain}}
+  // expected-note@-1 {{add '@available' attribute to enclosing class}}
+}
+
+@available(EnabledDomain)
+class DerivedAsAvailable: BaseAvailableInEnabledDomain { }
+
+@available(EnabledDomain)
+@available(DisabledDomain)
+class DerivedAsAvailable2: BaseAvailableInEnabledDomain { }
+
+@available(DisabledDomain)
+class DerivedLessAvailable: BaseAvailableInEnabledDomain { // expected-error {{'BaseAvailableInEnabledDomain' is only available in EnabledDomain}}
+  // expected-note@-1 {{add '@available' attribute to enclosing class}}
+}
+
+@available(EnabledDomain, unavailable)
+class DerivedUnavailable: BaseAvailableInEnabledDomain { } // expected-error {{'BaseAvailableInEnabledDomain' is only available in EnabledDomain}}
+
+@available(DisabledDomain, unavailable)
+class DerivedUnavailable2: BaseAvailableInEnabledDomain { } // expected-error {{'BaseAvailableInEnabledDomain' is only available in EnabledDomain}}
+// expected-note@-1 {{add '@available' attribute to enclosing class}}
+
+@available(EnabledDomain)
+@available(DisabledDomain, unavailable)
+class DerivedUnavailable3: BaseAvailableInEnabledDomain { }
+
diff --git a/test/Sema/availability_define.swift b/test/Availability/availability_define.swift
similarity index 100%
rename from test/Sema/availability_define.swift
rename to test/Availability/availability_define.swift
diff --git a/test/Sema/availability_define_multi_file.swift b/test/Availability/availability_define_multi_file.swift
similarity index 100%
rename from test/Sema/availability_define_multi_file.swift
rename to test/Availability/availability_define_multi_file.swift
diff --git a/test/Sema/availability_define_parsing.swift b/test/Availability/availability_define_parsing.swift
similarity index 100%
rename from test/Sema/availability_define_parsing.swift
rename to test/Availability/availability_define_parsing.swift
diff --git a/test/Sema/availability_deinit.swift b/test/Availability/availability_deinit.swift
similarity index 93%
rename from test/Sema/availability_deinit.swift
rename to test/Availability/availability_deinit.swift
index 872104e2374ed..701dac9e57f3b 100644
--- a/test/Sema/availability_deinit.swift
+++ b/test/Availability/availability_deinit.swift
@@ -49,7 +49,7 @@ class PotentiallyUnavailableDeinit {
 @available(macOS 51, *)
 func funcAvailable51() {}
 
-class AlwaysAvailable { // expected-note {{add @available attribute to enclosing class}}
+class AlwaysAvailable { // expected-note {{add '@available' attribute to enclosing class}}
   deinit {
     funcAvailable51() // expected-error {{'funcAvailable51()' is only available in macOS 51 or newer}}
     // expected-note@-1 {{add 'if #available' version check}}
diff --git a/test/Sema/availability_deprecated.swift b/test/Availability/availability_deprecated.swift
similarity index 100%
rename from test/Sema/availability_deprecated.swift
rename to test/Availability/availability_deprecated.swift
diff --git a/test/Sema/availability_deprecated_script_mode.swift b/test/Availability/availability_deprecated_script_mode.swift
similarity index 100%
rename from test/Sema/availability_deprecated_script_mode.swift
rename to test/Availability/availability_deprecated_script_mode.swift
diff --git a/test/Sema/availability_enum_case.swift b/test/Availability/availability_enum_case.swift
similarity index 91%
rename from test/Sema/availability_enum_case.swift
rename to test/Availability/availability_enum_case.swift
index 53c0405e78931..6512a52287399 100644
--- a/test/Sema/availability_enum_case.swift
+++ b/test/Availability/availability_enum_case.swift
@@ -11,7 +11,7 @@
 import availability_enum_case_other
 
 func ride(horse: Horse) {
-  // expected-note@-1 {{add @available attribute to enclosing global function}}
+  // expected-note@-1 {{add '@available' attribute to enclosing global function}}
 
   _ = Horse.kevin
   // expected-error@-1 {{'kevin' is only available in macOS 50 or newer}}
diff --git a/test/Sema/availability_global_actor.swift b/test/Availability/availability_global_actor.swift
similarity index 95%
rename from test/Sema/availability_global_actor.swift
rename to test/Availability/availability_global_actor.swift
index e715354394718..4a971b796ca02 100644
--- a/test/Sema/availability_global_actor.swift
+++ b/test/Availability/availability_global_actor.swift
@@ -23,7 +23,7 @@ actor SomeActor {}
 struct AlwaysAvailableWithAlwaysAvailableGA {}
 
 @Available51GA // expected-error {{'Available51GA' is only available in macOS 51 or newer}}
-struct AlwaysAvailableWithAvailable51GA {} // expected-note {{add @available attribute to enclosing struct}}
+struct AlwaysAvailableWithAvailable51GA {} // expected-note {{add '@available' attribute to enclosing struct}}
 
 @available(macOS 51, *)
 @Available51GA
diff --git a/test/Sema/availability_implicitly_unnecessary.swift b/test/Availability/availability_implicitly_unnecessary.swift
similarity index 100%
rename from test/Sema/availability_implicitly_unnecessary.swift
rename to test/Availability/availability_implicitly_unnecessary.swift
diff --git a/test/Availability/availability_isolated_any.swift b/test/Availability/availability_isolated_any.swift
new file mode 100644
index 0000000000000..1fdd39de1853a
--- /dev/null
+++ b/test/Availability/availability_isolated_any.swift
@@ -0,0 +1,43 @@
+// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx10.50
+
+// REQUIRES: OS=macosx
+
+// Concrete uses of @isolated(any) are fine.
+func expectIsolatedAny(fn: @isolated(any) () -> ()) {}
+
+func testConcrete1(fn: @isolated(any) () -> ()) {
+  expectIsolatedAny(fn: fn)
+}
+func testConcrete2(fn: @isolated(any) () -> ()) {
+  expectIsolatedAny {}
+}
+func testConcrete3(fn: @MainActor () -> ()) {
+  expectIsolatedAny {}
+}
+
+func testErasure(fn: @escaping @isolated(any) () -> ()) -> Any {
+  return fn // expected-error {{runtime support for '@isolated(any)' function types is only available in}}
+  // expected-note @-2 {{add '@available' attribute to enclosing global function}}
+  // expected-note @-2 {{add 'if #available' version check}}
+}
+
+func testCovariantErasure(fn: @escaping () -> @isolated(any) () -> Void) -> (() -> Any) {
+  return fn // expected-error {{runtime support for '@isolated(any)' function types is only available in}}
+  // expected-note @-2 {{add '@available' attribute to enclosing global function}}
+  // expected-note @-2 {{add 'if #available' version check}}
+}
+
+func testContravariantErasure(fn: @escaping (Any) -> Void) -> ((@escaping @isolated(any) () -> Void) -> Void) {
+  return fn // expected-error {{runtime support for '@isolated(any)' function types is only available in}}
+  // expected-note @-2 {{add '@available' attribute to enclosing global function}}
+  // expected-note @-2 {{add 'if #available' version check}}
+}
+
+protocol P {
+  associatedtype A
+}
+
+struct S: P { // expected-note {{add '@available' attribute to enclosing struct}}
+  typealias A = @isolated(any) () -> () // expected-error {{runtime support for '@isolated(any)' function types is only available in}}
+  // expected-note @-1 {{add '@available' attribute to enclosing type alias}}
+}
diff --git a/test/Sema/availability_literals.swift b/test/Availability/availability_literals.swift
similarity index 100%
rename from test/Sema/availability_literals.swift
rename to test/Availability/availability_literals.swift
diff --git a/test/Sema/availability_literals_inferred.swift b/test/Availability/availability_literals_inferred.swift
similarity index 100%
rename from test/Sema/availability_literals_inferred.swift
rename to test/Availability/availability_literals_inferred.swift
diff --git a/test/Availability/availability_macos.swift b/test/Availability/availability_macos.swift
new file mode 100644
index 0000000000000..06e326424ec62
--- /dev/null
+++ b/test/Availability/availability_macos.swift
@@ -0,0 +1,37 @@
+// RUN: %target-typecheck-verify-swift
+
+// REQUIRES: OS=macosx
+
+struct A {} // expected-note * {{found this candidate}}
+struct B {} // expected-note * {{found this candidate}}
+
+func ambiguousInFarFuture(_: A) {}
+
+@available(macOS 99, *)
+func ambiguousInFarFuture(_: B) {}
+
+struct S {
+  func ambiguousInFarFuture(_: A) {}
+}
+
+@available(macOS 99, *)
+extension S {
+  func ambiguousInFarFuture(_: B) {}
+}
+
+func testDeploymentTarget(_ s: S) {
+  ambiguousInFarFuture(.init())
+  s.ambiguousInFarFuture(.init())
+}
+
+@available(macOS 99, *)
+func testFarFuture(_ s: S) {
+  ambiguousInFarFuture(.init()) // expected-error {{ambiguous use of 'init()'}}
+  s.ambiguousInFarFuture(.init()) // expected-error {{ambiguous use of 'init()'}}
+}
+
+@available(macOS, unavailable)
+func testUnavailable(_ s: S) {
+  ambiguousInFarFuture(.init()) // expected-error {{ambiguous use of 'init()'}}
+  s.ambiguousInFarFuture(.init()) // expected-error {{ambiguous use of 'init()'}}
+}
diff --git a/test/Sema/availability_main_actor.swift b/test/Availability/availability_main_actor.swift
similarity index 100%
rename from test/Sema/availability_main_actor.swift
rename to test/Availability/availability_main_actor.swift
diff --git a/test/Sema/availability_parameterized_existential.swift b/test/Availability/availability_parameterized_existential.swift
similarity index 81%
rename from test/Sema/availability_parameterized_existential.swift
rename to test/Availability/availability_parameterized_existential.swift
index 1c144157c1a57..53e7d9cc078e8 100644
--- a/test/Sema/availability_parameterized_existential.swift
+++ b/test/Availability/availability_parameterized_existential.swift
@@ -29,7 +29,7 @@ func erase<T>(_ x: any P<T>) -> Any { return x }
 func nonerasingFunction<T>(_ f: @escaping (any P<T>) -> ()) -> Any { return 0 }
 
 func eraseFunction<T>(_ f: @escaping (any P<T>) -> ()) -> Any { return f } // expected-error {{runtime support for parameterized protocol types is only available in}}
-// expected-note@-1 {{add @available attribute to enclosing global function}}
+// expected-note@-1 {{add '@available' attribute to enclosing global function}}
 // expected-note@-2 {{add 'if #available' version check}}
 
 // These are okay because we can convert between existentials without metadata.
@@ -44,17 +44,17 @@ func eraseFunctionContravariant<T>(_ f: @escaping (Any) -> ()) -> ((any P<T>) ->
 // metadata.
 func eraseFunctionCovariantOptional<T>(_ f: @escaping () -> (any P<T>)?) -> (() -> Any) {
   return f // expected-error {{runtime support for parameterized protocol types is only available in}}
-  // expected-note@-2 {{add @available attribute to enclosing global function}}
+  // expected-note@-2 {{add '@available' attribute to enclosing global function}}
   // expected-note@-2 {{add 'if #available' version check}}
 }
 func eraseFunctionContravariantOptional<T>(_ f: @escaping (Any) -> ()) -> (((any P<T>)?) -> Any) {
   return f // expected-error {{runtime support for parameterized protocol types is only available in}}
-  // expected-note@-2 {{add @available attribute to enclosing global function}}
+  // expected-note@-2 {{add '@available' attribute to enclosing global function}}
   // expected-note@-2 {{add 'if #available' version check}}
 }
 
 func eraseOptional<T>(_ x: (any P<T>)?) -> Any { return x }
-// expected-note@-1 {{add @available attribute to enclosing global function}}
+// expected-note@-1 {{add '@available' attribute to enclosing global function}}
 // expected-error@-2 {{runtime support for parameterized protocol types is only available in}}
 // expected-note@-3 {{add 'if #available' version check}}
 // expected-warning@-4 {{expression implicitly coerced from '(any P<T>)?' to 'Any'}}
@@ -63,40 +63,40 @@ func eraseOptional<T>(_ x: (any P<T>)?) -> Any { return x }
 // expected-note@-7 {{explicitly cast to 'Any' with 'as Any' to silence this warning}}
 
 func eraseOptional2<T>(_ x: (any P<T>)?) -> Any { return x as Any }
-// expected-note@-1 {{add @available attribute to enclosing global function}}
+// expected-note@-1 {{add '@available' attribute to enclosing global function}}
 // expected-error@-2 {{runtime support for parameterized protocol types is only available in}}
 // expected-note@-3 {{add 'if #available' version check}}
 
 func tupleOut<T>() -> (any P<T>, Int) { return tupleOut() }
 func tupleIn<T>(_ xs: (any P<T>, Int)) -> Int { return tupleIn(xs) }
 func wrap<T>(_ x: any P<T>) -> Wrapper<any P<T>> { return wrap(x) } // expected-error {{runtime support for parameterized protocol types is only available in}}
-// expected-note@-1 {{add @available attribute to enclosing global function}}
+// expected-note@-1 {{add '@available' attribute to enclosing global function}}
 func optionalWrap<T>(_ x: any P<T>) -> Wrapper<(any P<T>)?> { return optionalWrap(x) } // expected-error {{runtime support for parameterized protocol types is only available in}}
-// expected-note@-1 {{add @available attribute to enclosing global function}}
+// expected-note@-1 {{add '@available' attribute to enclosing global function}}
 
-struct UnavailableWitness: P { // expected-note {{add @available attribute to enclosing struct}}
+struct UnavailableWitness: P { // expected-note {{add '@available' attribute to enclosing struct}}
   typealias T = any P<String> // expected-error {{runtime support for parameterized protocol types is only available in}}
-  // expected-note@-1 {{add @available attribute to enclosing type alias}}
+  // expected-note@-1 {{add '@available' attribute to enclosing type alias}}
 }
 
-struct UnavailableOptionalWitness: P { // expected-note {{add @available attribute to enclosing struct}}
+struct UnavailableOptionalWitness: P { // expected-note {{add '@available' attribute to enclosing struct}}
   typealias T = (any P<String>)? // expected-error {{runtime support for parameterized protocol types is only available in}}
-  // expected-note@-1 {{add @available attribute to enclosing type alias}}
+  // expected-note@-1 {{add '@available' attribute to enclosing type alias}}
 }
 
-struct UnavailableWrappedWitness: P { // expected-note 2 {{add @available attribute to enclosing struct}}
+struct UnavailableWrappedWitness: P { // expected-note 2 {{add '@available' attribute to enclosing struct}}
   typealias T = Wrapper<any P<String>> // expected-error 2 {{runtime support for parameterized protocol types is only available in}}
-  // expected-note@-1 2 {{add @available attribute to enclosing type alias}}
+  // expected-note@-1 2 {{add '@available' attribute to enclosing type alias}}
 }
 
-struct ParameterizedMembers { // expected-note {{add @available attribute to enclosing struct}}
+struct ParameterizedMembers { // expected-note {{add '@available' attribute to enclosing struct}}
   var ok: any P<String>
   var okOptional: (any P<String>)?
 
   var broken: Wrapper<(any P<String>)?> // expected-error {{runtime support for parameterized protocol types is only available in}}
 }
 
-func casts() { // expected-note 4 {{add @available attribute to enclosing global function}}
+func casts() { // expected-note 4 {{add '@available' attribute to enclosing global function}}
   struct Value: P { typealias T = String }
 
   let _ = Value() as any P<String> // OK
@@ -122,7 +122,7 @@ func casts() { // expected-note 4 {{add @available attribute to enclosing global
 }
 
 // FIXME: It's a little aggressive to also ban metatypes.
-func metatypes<T>(_ x: T.Type) {  // expected-note 2 {{add @available attribute to enclosing global function}}
+func metatypes<T>(_ x: T.Type) {  // expected-note 2 {{add '@available' attribute to enclosing global function}}
   metatypes((any P<T>).self)
   // expected-error@-1 {{runtime support for parameterized protocol types is only available in}}
   // expected-note@-2 {{add 'if #available' version check}}
@@ -141,7 +141,7 @@ func tupleConversion2<T>(_ tuple: (any P<T>, Int)) {
   _ = converted
 }
 func tupleConversion3<T>(_ tuple: ((any P<T>)?, Int)) {
-  // expected-note @-1 {{add @available attribute to enclosing global function}}
+  // expected-note @-1 {{add '@available' attribute to enclosing global function}}
 
   let converted: (Any, Int?) = tuple // expected-error {{runtime support for parameterized protocol types is only available in}}
   // expected-note @-1 {{add 'if #available' version check}}
@@ -158,7 +158,7 @@ func tupleCovariantConversion1<T>(fn: @escaping () -> (any P<T>, Int)) -> (() ->
   return fn
 }
 func tupleCovariantConversion2<T>(fn: @escaping () -> ((any P<T>)?, Int)) -> (() -> (Any, Int)) {
-  // expected-note @-1 {{add @available attribute to enclosing global function}}
+  // expected-note @-1 {{add '@available' attribute to enclosing global function}}
 
   return fn // expected-error {{runtime support for parameterized protocol types is only available in}}
   // expected-note @-1 {{add 'if #available' version check}}
diff --git a/test/Sema/availability_scopes.swift b/test/Availability/availability_scopes.swift
similarity index 91%
rename from test/Sema/availability_scopes.swift
rename to test/Availability/availability_scopes.swift
index b3a3ea56964c1..e0543b00ce8c0 100644
--- a/test/Sema/availability_scopes.swift
+++ b/test/Availability/availability_scopes.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -dump-availability-scopes %s -target %target-cpu-apple-macos50 > %t.dump 2>&1
+// RUN: %target-swift-frontend -typecheck -dump-availability-scopes %s -target %target-cpu-apple-macos50 -swift-version 5 > %t.dump 2>&1
 // RUN: %FileCheck --strict-whitespace %s < %t.dump
 
 // REQUIRES: OS=macosx
@@ -253,19 +253,19 @@ extension SomeClass {
 
 // CHECK-NEXT: {{^}}  (decl_implicit version=50 decl=extension.SomeClass
 // CHECK-NEXT: {{^}}    (decl version=50 unavailable=macOS decl=extension.SomeClass
-// CHECK-NEXT: {{^}}      (decl version=51 unavailable=macOS decl=functionWithStmtConditionsInUnavailableExt()
+// CHECK-NEXT: {{^}}      (decl version=50 unavailable=macOS decl=functionWithStmtConditionsInUnavailableExt()
 // CHECK-NEXT: {{^}}        (condition_following_availability version=52 unavailable=macOS
 // CHECK-NEXT: {{^}}          (condition_following_availability version=53 unavailable=macOS
 // CHECK-NEXT: {{^}}        (if_then version=53 unavailable=macOS
 // CHECK-NEXT: {{^}}          (condition_following_availability version=54 unavailable=macOS
 // CHECK-NEXT: {{^}}          (if_then version=54 unavailable=macOS
 // CHECK-NEXT: {{^}}            (condition_following_availability version=55 unavailable=macOS
-// CHECK-NEXT: {{^}}            (decl version=55 unavailable=macOS decl=funcInGuardElse()
+// CHECK-NEXT: {{^}}            (decl version=54 unavailable=macOS decl=funcInGuardElse()
 // CHECK-NEXT: {{^}}            (guard_fallthrough version=55 unavailable=macOS
 // CHECK-NEXT: {{^}}              (condition_following_availability version=56 unavailable=macOS
 // CHECK-NEXT: {{^}}              (guard_fallthrough version=56 unavailable=macOS
-// CHECK-NEXT: {{^}}          (decl version=57 unavailable=macOS decl=funcInInnerIfElse()
-// CHECK-NEXT: {{^}}        (decl version=53 unavailable=macOS decl=funcInOuterIfElse()
+// CHECK-NEXT: {{^}}          (decl version=53 unavailable=macOS decl=funcInInnerIfElse()
+// CHECK-NEXT: {{^}}        (decl version=50 unavailable=macOS decl=funcInOuterIfElse()
 @available(OSX, unavailable)
 extension SomeClass {
   @available(OSX 51, *)
@@ -401,7 +401,7 @@ extension SomeEnum {
 // CHECK-NEXT: {{^}}  (decl_implicit version=50 decl=extension.SomeEnum
 // CHECK-NEXT: {{^}}    (decl version=50 unavailable=macOS decl=extension.SomeEnum
 // CHECK-NEXT: {{^}}      (decl_implicit version=50 unavailable=macOS decl=availableMacOS_52
-// CHECK-NEXT: {{^}}        (decl version=52 unavailable=macOS decl=availableMacOS_52
+// CHECK-NEXT: {{^}}        (decl version=50 unavailable=macOS decl=availableMacOS_52
 // CHECK-NEXT: {{^}}      (decl version=50 unavailable=* decl=neverAvailable()
 
 @available(macOS, unavailable)
@@ -418,10 +418,25 @@ extension SomeEnum {
 
 // CHECK-NEXT: {{^}}  (decl version=50 unavailable=macOS decl=unavailableOnMacOSAndIntroduced()
 
-@available(macOS, unavailable, introduced: 52)
+@available(macOS, unavailable)
+@available(macOS, introduced: 52)
 func unavailableOnMacOSAndIntroduced() {
 }
 
+// CHECK-NEXT: {{^}}  (decl version=50 unavailable=macOS decl=introducedOnMacOSAndUnavailable()
+
+@available(macOS, introduced: 53)
+@available(macOS, unavailable)
+func introducedOnMacOSAndUnavailable() {
+}
+
+
+// CHECK-NEXT: {{^}}  (decl version=50 unavailable=macOS decl=unavailableOnMacOSAndIntroducedSameAttr()
+
+@available(macOS, unavailable, introduced: 54)
+func unavailableOnMacOSAndIntroducedSameAttr() {
+}
+
 // CHECK-NEXT: {{^}}  (decl version=50 unavailable=* decl=NeverAvailable
 // CHECK-NEXT: {{^}}    (decl version=50 unavailable=* decl=unavailableOnMacOS()
 
@@ -439,6 +454,23 @@ func deprecatedOnMacOS() {
   let x = 1
 }
 
+// Since availableOniOS() doesn't have any active @available attributes it
+// shouldn't create a scope.
+// CHECK-NOT: availableOniOS
+
+@available(iOS, introduced: 53)
+func availableOniOS() { }
+
+// CHECK-NEXT: {{^}}  (decl version=50 decl=availableInSwift5
+
+@available(swift 5)
+func availableInSwift5() { }
+
+// CHECK-NEXT: {{^}}  (decl version=50 unavailable=swift decl=availableInSwift6
+
+@available(swift 6)
+func availableInSwift6() { }
+
 // CHECK-NEXT: {{^}}  (decl version=51 decl=FinalDecl
 
 @available(OSX 51, *)
diff --git a/test/Sema/availability_scopes_custom_domains.swift b/test/Availability/availability_scopes_custom_domains.swift
similarity index 100%
rename from test/Sema/availability_scopes_custom_domains.swift
rename to test/Availability/availability_scopes_custom_domains.swift
diff --git a/test/Sema/availability_scopes_target_min_inlining.swift b/test/Availability/availability_scopes_target_min_inlining.swift
similarity index 100%
rename from test/Sema/availability_scopes_target_min_inlining.swift
rename to test/Availability/availability_scopes_target_min_inlining.swift
diff --git a/test/Sema/availability_scopes_target_min_inlining_maccatalyst.swift b/test/Availability/availability_scopes_target_min_inlining_maccatalyst.swift
similarity index 100%
rename from test/Sema/availability_scopes_target_min_inlining_maccatalyst.swift
rename to test/Availability/availability_scopes_target_min_inlining_maccatalyst.swift
diff --git a/test/Sema/availability_script_mode.swift b/test/Availability/availability_script_mode.swift
similarity index 100%
rename from test/Sema/availability_script_mode.swift
rename to test/Availability/availability_script_mode.swift
diff --git a/test/Sema/availability_soft_deprecated.swift b/test/Availability/availability_soft_deprecated.swift
similarity index 100%
rename from test/Sema/availability_soft_deprecated.swift
rename to test/Availability/availability_soft_deprecated.swift
diff --git a/test/Sema/availability_stored.swift b/test/Availability/availability_stored.swift
similarity index 100%
rename from test/Sema/availability_stored.swift
rename to test/Availability/availability_stored.swift
diff --git a/test/Sema/availability_stored_unavailable.swift b/test/Availability/availability_stored_unavailable.swift
similarity index 100%
rename from test/Sema/availability_stored_unavailable.swift
rename to test/Availability/availability_stored_unavailable.swift
diff --git a/test/Sema/availability_stored_unavailable_maccatalyst.swift b/test/Availability/availability_stored_unavailable_maccatalyst.swift
similarity index 100%
rename from test/Sema/availability_stored_unavailable_maccatalyst.swift
rename to test/Availability/availability_stored_unavailable_maccatalyst.swift
diff --git a/test/Sema/availability_swift_versions.swift b/test/Availability/availability_swift_language_mode.swift
similarity index 100%
rename from test/Sema/availability_swift_versions.swift
rename to test/Availability/availability_swift_language_mode.swift
diff --git a/test/Availability/availability_swift_runtime.swift b/test/Availability/availability_swift_runtime.swift
new file mode 100644
index 0000000000000..dd7913d7a95f3
--- /dev/null
+++ b/test/Availability/availability_swift_runtime.swift
@@ -0,0 +1,30 @@
+// RUN: %target-typecheck-verify-swift -parse-as-library -enable-experimental-feature SwiftRuntimeAvailability -min-swift-runtime-version 5.5
+
+// REQUIRES: swift_feature_SwiftRuntimeAvailability
+
+@available(Swift 5.0, *)
+func availableInSwift5_0Runtime() { }
+
+@available(Swift 5.5, *)
+func availableInSwift5_5Runtime() { }
+
+@available(Swift 6.0, *)
+func availableInSwift6_0Runtime() { }
+
+func alwaysAvailable() {
+  // expected-note@-1 {{add '@available' attribute to enclosing global function}}{{1-1=@available(Swift 6.0)\n}}
+
+  availableInSwift5_0Runtime()
+  availableInSwift5_5Runtime()
+  availableInSwift6_0Runtime() // expected-error {{'availableInSwift6_0Runtime()' is only available in Swift 6.0 or newer}}
+  // expected-note@-1 {{add 'if #available' version check}}{{3-31=if #available(Swift 6.0) {\n      availableInSwift6_0Runtime()\n  \} else {\n      // Fallback on earlier versions\n  \}}}
+
+  if #available(Swift 6.0, *) {
+    availableInSwift6_0Runtime()
+  }
+}
+
+@available(Swift 6.0, *)
+func availableSwift6() {
+  availableInSwift6_0Runtime()
+}
diff --git a/test/Sema/availability_swiftui.swift b/test/Availability/availability_swiftui.swift
similarity index 100%
rename from test/Sema/availability_swiftui.swift
rename to test/Availability/availability_swiftui.swift
diff --git a/test/Availability/availability_target_min_inlining.swift b/test/Availability/availability_target_min_inlining.swift
new file mode 100644
index 0000000000000..ef560b2dfa503
--- /dev/null
+++ b/test/Availability/availability_target_min_inlining.swift
@@ -0,0 +1,2230 @@
+// A module with library evolution enabled has two different "minimum versions".
+// One, the minimum deployment target, is the lowest version that non-ABI
+// declarations and bodies of non-inlinable functions will ever see. The other,
+// the minimum inlining target, is the lowest version that ABI declarations and
+// inlinable bodies will ever see.
+//
+// Test that we use the right version floor in the right places.
+
+// REQUIRES: OS=macosx
+
+// Primary execution of this test. Uses the default minimum inlining version,
+// which is the version when Swift was introduced.
+// RUN: %target-typecheck-verify-swift -swift-version 5 -enable-library-evolution -parse-as-library -module-name Test -target %target-next-stable-abi-triple -target-min-inlining-version min
+
+
+// Check that `-library-level api` implies `-target-min-inlining-version min`
+// RUN: %target-typecheck-verify-swift -swift-version 5 -enable-library-evolution -parse-as-library -module-name Test -target %target-next-stable-abi-triple -library-level api -require-explicit-availability=ignore
+
+
+// Check that these rules are only applied when requested and that at least some
+// diagnostics are not present without it.
+// RUN: not %target-typecheck-verify-swift -swift-version 5 -enable-library-evolution -parse-as-library -module-name Test -target %target-next-stable-abi-triple 2>&1 | %FileCheck --check-prefix INLINING-VERSION-TARGET %s
+
+
+// Check that -target-min-inlining-version overrides -library-level, allowing
+// library owners to disable this behavior for API libraries if needed.
+// RUN: not %target-typecheck-verify-swift -swift-version 5 -enable-library-evolution -parse-as-library -module-name Test -target %target-next-stable-abi-triple -target-min-inlining-version target -library-level api -require-explicit-availability=ignore 2>&1 | %FileCheck --check-prefix INLINING-VERSION-TARGET %s
+
+
+// INLINING-VERSION-TARGET: error: expected error not produced
+// INLINING-VERSION-TARGET: {'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}
+
+// MARK: - Struct definitions
+
+/// Declaration with no availability annotation. Should be inferred as minimum
+/// inlining target.
+public struct NoAvailable {
+  @usableFromInline internal init() {}
+  init<T>(_ t: T) {}
+}
+
+@available(macOS 10.9, *)
+public struct BeforeInliningTarget {
+  @usableFromInline internal init() {}
+  init<T>(_ t: T) {}
+}
+
+@available(macOS 10.10, *)
+public struct AtInliningTarget {
+  @usableFromInline internal init() {}
+  init<T>(_ t: T) {}
+}
+
+@available(macOS 10.14.5, *)
+public struct BetweenTargets { // expected-note {{enclosing scope requires availability of macOS 10.14.5 or newer}}
+  @usableFromInline internal init() {}
+  init<T>(_ t: T) {}
+}
+
+@available(macOS 10.15, *)
+public struct AtDeploymentTarget {
+  @usableFromInline internal init() {}
+  init<T>(_ t: T) {}
+}
+
+@available(macOS 11, *)
+public struct AfterDeploymentTarget {
+  @usableFromInline internal init() {}
+  init<T>(_ t: T) {}
+}
+
+@available(macOS, obsoleted: 10.14.5)
+public struct ObsoletedBetweenTargets { // expected-note * {{'ObsoletedBetweenTargets' was obsoleted in macOS 10.14.5}}
+  @usableFromInline internal init() {}
+  init<T>(_ t: T) {}
+}
+
+@available(macOS, obsoleted: 10.15)
+public struct ObsoletedAtDeploymentTarget { // expected-note * {{'ObsoletedAtDeploymentTarget' was obsoleted in macOS 10.15}}
+  @usableFromInline internal init() {}
+  init<T>(_ t: T) {}
+}
+
+@available(macOS, unavailable)
+public struct Unavailable { // expected-note * {{'Unavailable' has been explicitly marked unavailable here}}
+  @usableFromInline internal init() {}
+  init<T>(_ t: T) {}
+}
+
+// MARK: - Protocol definitions
+
+public protocol NoAvailableProto {}
+
+@available(macOS 10.9, *)
+public protocol BeforeInliningTargetProto {}
+
+@available(macOS 10.10, *)
+public protocol AtInliningTargetProto {}
+
+@available(macOS 10.14.5, *)
+public protocol BetweenTargetsProto {}
+
+@available(macOS 10.15, *)
+public protocol AtDeploymentTargetProto {}
+
+@available(macOS 11, *)
+public protocol AfterDeploymentTargetProto {}
+
+@available(macOS, obsoleted: 10.14.5)
+public protocol ObsoletedBetweenTargetsProto {} // expected-note * {{'ObsoletedBetweenTargetsProto' was obsoleted in macOS 10.14.5}}
+
+@available(macOS, unavailable)
+public protocol UnavailableProto {}
+
+// MARK: - Class definitions
+
+public class NoAvailableClass {}
+
+@available(macOS 10.9, *)
+public class BeforeInliningTargetClass {}
+
+@available(macOS 10.10, *)
+public class AtInliningTargetClass {}
+
+@available(macOS 10.14.5, *)
+public class BetweenTargetsClass {}
+
+@available(macOS 10.15, *)
+public class AtDeploymentTargetClass {}
+
+@available(macOS 11, *)
+public class AfterDeploymentTargetClass {}
+
+@available(macOS, obsoleted: 10.14.5)
+public class ObsoletedBetweenTargetsClass {} // expected-note * {{'ObsoletedBetweenTargetsClass' was obsoleted in macOS 10.14.5}}
+
+@available(macOS, unavailable)
+public class UnavailableClass {}
+
+
+// MARK: - Internal functions
+
+//
+// Both the signature and the body of internal functions should be typechecked
+// using the minimum deployment target.
+//
+
+internal func internalFn( // expected-note 3 {{add '@available' attribute to enclosing global function}}
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+// MARK: - Resilient functions
+
+//
+// The body of a resilient function is typechecked using the minimum deployment
+// but the function's signature should be checked with the inlining target.
+//
+
+public func deployedUseNoAvailable( // expected-note 5 {{add '@available' attribute}}
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+  _: ObsoletedAtDeploymentTarget,
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedAtDeploymentTarget() // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS 10.9, *)
+public func deployedUseBeforeInliningTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+  _: ObsoletedAtDeploymentTarget,
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedAtDeploymentTarget() // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS 10.10, *)
+public func deployedUseAtInliningTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+  _: ObsoletedAtDeploymentTarget,
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedAtDeploymentTarget() // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS 10.14.5, *)
+public func deployedUseBetweenTargets(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _: ObsoletedAtDeploymentTarget,
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedAtDeploymentTarget() // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS 10.15, *)
+public func deployedUseAtDeploymentTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _: ObsoletedAtDeploymentTarget, // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedAtDeploymentTarget() // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS 11, *)
+public func deployedUseAfterDeploymentTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget,
+  _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _: ObsoletedAtDeploymentTarget, // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget()
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedAtDeploymentTarget() // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+}
+
+@available(macOS, unavailable)
+public func alwaysUnavailable(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget,
+  _: ObsoletedBetweenTargets,
+  _: ObsoletedAtDeploymentTarget,
+  _: Unavailable
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget()
+  _ = ObsoletedBetweenTargets()
+  _ = ObsoletedAtDeploymentTarget()
+  _ = Unavailable()
+  
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS, obsoleted: 10.9)
+public func obsoletedBeforeInliningTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget,
+  _: ObsoletedBetweenTargets,
+  _: ObsoletedAtDeploymentTarget,
+  _: Unavailable
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget()
+  _ = ObsoletedBetweenTargets()
+  _ = ObsoletedAtDeploymentTarget()
+  _ = Unavailable()
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS, obsoleted: 10.10)
+public func obsoletedAtInliningTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget,
+  _: ObsoletedBetweenTargets,
+  _: ObsoletedAtDeploymentTarget,
+  _: Unavailable
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget()
+  _ = ObsoletedBetweenTargets()
+  _ = ObsoletedAtDeploymentTarget()
+  _ = Unavailable()
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS, obsoleted: 10.14.5)
+public func obsoletedBetweenTargets(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+  _: ObsoletedAtDeploymentTarget,
+  _: Unavailable, // expected-error {{'Unavailable' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget()
+  _ = ObsoletedBetweenTargets()
+  _ = ObsoletedAtDeploymentTarget()
+  _ = Unavailable()
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS, obsoleted: 10.15)
+public func obsoletedAtDeploymentTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+  _: ObsoletedAtDeploymentTarget,
+  _: Unavailable // expected-error {{'Unavailable' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget()
+  _ = ObsoletedBetweenTargets()
+  _ = ObsoletedAtDeploymentTarget()
+  _ = Unavailable()
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@available(macOS, obsoleted: 11)
+public func obsoletedAfterDeploymentTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+  _: ObsoletedAtDeploymentTarget,
+  _: Unavailable, // expected-error {{'Unavailable' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedAtDeploymentTarget() // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+  _ = Unavailable() // expected-error {{'Unavailable' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+@_spi(Private)
+public func spiDeployedUseNoAvailable( // expected-note 3 {{add '@available' attribute}}
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _: ObsoletedAtDeploymentTarget, // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedAtDeploymentTarget() // expected-error {{'ObsoletedAtDeploymentTarget' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+// MARK: - @inlinable functions
+
+//
+// Both the bodies and signatures of inlinable functions need to be typechecked
+// using the minimum inlining target.
+//
+
+@inlinable public func inlinedUseNoAvailable( // expected-note 13 {{add '@available' attribute}}
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+) {
+  defer {
+    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    _ = ObsoletedBetweenTargets()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets()
+
+  if #available(macOS 10.14.5, *) {
+    _ = BetweenTargets()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 10.15, *) {
+    _ = AtDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+
+  // Repeat everything with pattern binding decls instead of discard expressions.
+  defer {
+    let _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+    let _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    let _ = ObsoletedBetweenTargets()
+
+  }
+  let _ = NoAvailable()
+  let _ = BeforeInliningTarget()
+  let _ = AtInliningTarget()
+  let _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  let _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  let _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  let _ = ObsoletedBetweenTargets()
+
+  if #available(macOS 10.14.5, *) {
+    let _ = BetweenTargets()
+    let _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 10.15, *) {
+    let _ = AtDeploymentTarget()
+    let _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 11, *) {
+    let _ = AfterDeploymentTarget()
+    let _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+}
+
+@available(macOS 10.9, *)
+@inlinable public func inlinedUseBeforeInliningTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+) {
+  defer {
+    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    _ = ObsoletedBetweenTargets()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets()
+
+  if #available(macOS 10.14.5, *) {
+    _ = BetweenTargets()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 10.15, *) {
+    _ = AtDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+}
+
+@available(macOS 10.10, *)
+@inlinable public func inlinedUseAtInliningTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+) {
+  defer {
+    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    _ = ObsoletedBetweenTargets()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets()
+
+  if #available(macOS 10.14.5, *) {
+    _ = BetweenTargets()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 10.15, *) {
+    _ = AtDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+}
+
+@available(macOS 10.14.5, *)
+@inlinable public func inlinedUseBetweenTargets(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  if #available(macOS 10.15, *) {
+    _ = AtDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+}
+
+@available(macOS 10.15, *)
+@inlinable public func inlinedUseAtDeploymentTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+}
+
+@available(macOS 11, *)
+@inlinable public func inlinedUseAfterDeploymentTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget,
+  _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget()
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+}
+
+@available(macOS, unavailable)
+@inlinable public func inlinedAlwaysUnavailable(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget,
+  _: ObsoletedBetweenTargets,
+  _: Unavailable
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget()
+  _ = ObsoletedBetweenTargets()
+  _ = Unavailable()
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets()
+  }
+}
+
+@_spi(Private)
+@inlinable public func spiInlinedUseNoAvailable( // expected-note 3 {{add '@available' attribute}}
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+}
+
+// MARK: - @inlinable global property accessors
+
+@inlinable public var inlinedNoAvailableGlobal: Any { // expected-note 3 {{add '@available' attribute to enclosing var}}
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
+  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+
+  return ()
+}
+
+@inlinable public var inlinedNoAvailableGlobalExplicitGetter: Any { // expected-note 3 {{add '@available' attribute to enclosing var}}
+  get {
+    _ = NoAvailable()
+    _ = BeforeInliningTarget()
+    _ = AtInliningTarget()
+    _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
+    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+
+    if #available(macOS 11, *) {
+      _ = AfterDeploymentTarget()
+    }
+
+    return ()
+  }
+}
+
+@available(macOS 10.15, *)
+@inlinable public var inlinedAtDeploymentTargetGlobal: Any {
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+
+  return ()
+}
+
+@inlinable public var inlinedGlobalGetterAtDeploymentTarget: Any { // expected-note {{add '@available' attribute to enclosing var}}
+  @available(macOS 10.15, *)
+  get {
+    _ = NoAvailable()
+    _ = BeforeInliningTarget()
+    _ = AtInliningTarget()
+    _ = BetweenTargets()
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+
+    if #available(macOS 11, *) {
+      _ = AfterDeploymentTarget()
+    }
+
+    return ()
+  }
+}
+
+@_spi(Private)
+@inlinable public var inlinedNoAvailableSPIGlobal: Any { // expected-note {{add '@available' attribute to enclosing var}}
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+
+  return ()
+}
+
+@inlinable public var inlinedNoAvailableGlobalSPISetter: Any { // expected-note {{add '@available' attribute to enclosing var}}
+  get {
+    fatalError()
+  }
+  @_spi(Private)
+  set {
+    _ = NoAvailable()
+    _ = BeforeInliningTarget()
+    _ = AtInliningTarget()
+    _ = BetweenTargets()
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+
+    if #available(macOS 11, *) {
+      _ = AfterDeploymentTarget()
+    }
+  }
+}
+
+@available(macOS, unavailable)
+@inlinable public var inlinedUnavailableGlobal: Any {
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget()
+
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+  }
+
+  return ()
+}
+
+@inlinable public var inlinedNoAvailableGlobalUnavailableSetter: Any {
+  get {
+    fatalError()
+  }
+  @available(macOS, unavailable)
+  set {
+    _ = NoAvailable()
+    _ = BeforeInliningTarget()
+    _ = AtInliningTarget()
+    _ = BetweenTargets()
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget()
+
+    if #available(macOS 11, *) {
+      _ = AfterDeploymentTarget()
+    }
+  }
+}
+
+// MARK: - @_alwaysEmitIntoClient functions
+
+// @_alwaysEmitIntoClient acts like @inlinable.
+
+@_alwaysEmitIntoClient public func aEICUseNoAvailable( // expected-note 8 {{add '@available' attribute}}
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+) {
+  defer {
+    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    _ = ObsoletedBetweenTargets()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets()
+
+  if #available(macOS 10.14.5, *) {
+    _ = BetweenTargets()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 10.15, *) {
+    _ = AtDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+}
+
+
+// MARK: - @backDeployed functions
+
+// @backDeployed acts like @inlinable.
+
+@available(macOS 10.10, *)
+@backDeployed(before: macOS 999.0)
+public func backDeployedToInliningTarget(
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: ObsoletedBetweenTargets,
+) {
+  defer {
+    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    _ = ObsoletedBetweenTargets()
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+  _ = ObsoletedBetweenTargets()
+
+  if #available(macOS 10.14.5, *) {
+    _ = BetweenTargets()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 10.15, *) {
+    _ = AtDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+  if #available(macOS 11, *) {
+    _ = AfterDeploymentTarget()
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  }
+}
+
+
+// MARK: - Default arguments
+
+// Default arguments act like @inlinable when in a public function.
+
+public func defaultArgsUseNoAvailable( // expected-note 3 {{add '@available' attribute}}
+  _: Any = NoAvailable.self,
+  _: Any = BeforeInliningTarget.self,
+  _: Any = AtInliningTarget.self,
+  _: Any = BetweenTargets.self, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  _: Any = AtDeploymentTarget.self, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  _: Any = AfterDeploymentTarget.self, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: Any = ObsoletedBetweenTargets.self,
+) {}
+
+func defaultArgsUseInternal( // expected-note {{add '@available' attribute}}
+  _: Any = NoAvailable.self,
+  _: Any = BeforeInliningTarget.self,
+  _: Any = AtInliningTarget.self,
+  _: Any = BetweenTargets.self,
+  _: Any = AtDeploymentTarget.self,
+  _: Any = AfterDeploymentTarget.self, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: Any = ObsoletedBetweenTargets.self, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+) {}
+
+@available(macOS, unavailable)
+public func defaultArgsUseUnavailable(
+  _: Any = NoAvailable.self,
+  _: Any = BeforeInliningTarget.self,
+  _: Any = AtInliningTarget.self,
+  _: Any = BetweenTargets.self,
+  _: Any = AtDeploymentTarget.self,
+  _: Any = AfterDeploymentTarget.self,
+  _: Any = ObsoletedBetweenTargets.self,
+  _: Any = Unavailable.self
+) {}
+
+@_spi(Private)
+public func spiDefaultArgsUseNoAvailable( // expected-note 1 {{add '@available' attribute}}
+  _: Any = NoAvailable.self,
+  _: Any = BeforeInliningTarget.self,
+  _: Any = AtInliningTarget.self,
+  _: Any = BetweenTargets.self,
+  _: Any = AtDeploymentTarget.self,
+  _: Any = AfterDeploymentTarget.self, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  _: Any = ObsoletedBetweenTargets.self, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+) {}
+
+// Verify that complex default argument expressions are checked appropriately.
+public func defaultArgsClosureExprNoAvailable( // expected-note 3 {{add '@available' attribute}}
+  _: Int = {
+    _ = NoAvailable.self
+    _ = BeforeInliningTarget.self
+    _ = AtInliningTarget.self
+    _ = BetweenTargets.self // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
+    _ = AtDeploymentTarget.self // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
+    _ = AfterDeploymentTarget.self // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available' version check}}
+    _ = ObsoletedBetweenTargets.self
+    if #available(macOS 10.14.5, *) {
+      _ = BetweenTargets.self
+    }
+    if #available(macOS 10.15, *) {
+      _ = AtDeploymentTarget.self
+    }
+    if #available(macOS 11, *) {
+      _ = AfterDeploymentTarget.self
+    }
+    return 42
+  }()
+) {}
+
+func defaultArgsClosureExprInternal( // expected-note {{add '@available' attribute}}
+  _: Int = {
+    _ = NoAvailable.self
+    _ = BeforeInliningTarget.self
+    _ = AtInliningTarget.self
+    _ = BetweenTargets.self
+    _ = AtDeploymentTarget.self
+    _ = AfterDeploymentTarget.self // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available' version check}}
+    _ = ObsoletedBetweenTargets.self // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+    if #available(macOS 11, *) {
+      _ = AfterDeploymentTarget.self
+    }
+    return 42
+  }()
+) {}
+
+
+// MARK: - Properties
+
+@propertyWrapper
+public struct PropertyWrapper<T> {
+  public var wrappedValue: T
+
+  public init(wrappedValue value: T) { self.wrappedValue = value }
+  public init(_ value: T) { self.wrappedValue = value }
+}
+
+public struct PublicStruct { // expected-note 21 {{add '@available' attribute}}
+  // Public property declarations are exposed.
+  public var aPublic: NoAvailable,
+             bPublic: BeforeInliningTarget,
+             cPublic: AtInliningTarget,
+             dPublic: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+             ePublic: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+             fPublic: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+             gPublic: ObsoletedBetweenTargets
+
+  @available(macOS 10.14.5, *)
+  public var aPublicAvailBetween: NoAvailable,
+             bPublicAvailBetween: BeforeInliningTarget,
+             cPublicAvailBetween: AtInliningTarget,
+             dPublicAvailBetween: BetweenTargets,
+             ePublicAvailBetween: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+             fPublicAvailBetween: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+             gPublicAvailBetween: ObsoletedBetweenTargets // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  @_spi(Private)
+  public var aSPI: NoAvailable,
+             bSPI: BeforeInliningTarget,
+             cSPI: AtInliningTarget,
+             dSPI: BetweenTargets,
+             eSPI: AtDeploymentTarget,
+             fSPI: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+             gSPI: ObsoletedBetweenTargets // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  @available(macOS, unavailable)
+  public var aUnavailable: NoAvailable {
+    NoAvailable()
+  }
+
+  @available(macOS, unavailable)
+  public var bUnavailable: BeforeInliningTarget {
+    BeforeInliningTarget()
+  }
+
+  @available(macOS, unavailable)
+  public var cUnavailable: AtInliningTarget {
+    AtInliningTarget()
+  }
+
+  @available(macOS, unavailable)
+  public var dUnavailable: BetweenTargets {
+    BetweenTargets()
+  }
+
+  @available(macOS, unavailable)
+  public var eUnavailable: AtDeploymentTarget {
+    AtDeploymentTarget()
+  }
+
+  @available(macOS, unavailable)
+  public var fUnavailable: AfterDeploymentTarget {
+    AfterDeploymentTarget()
+  }
+
+  @available(macOS, unavailable)
+  public var gUnavailable: ObsoletedBetweenTargets {
+    ObsoletedBetweenTargets()
+  }
+
+  // The inferred types of public properties are exposed.
+  public var aPublicInferred = NoAvailable(),
+             bPublicInferred = BeforeInliningTarget(),
+             cPublicInferred = AtInliningTarget(),
+             dPublicInferred = BetweenTargets(), // FIXME: Inferred type should be diagnosed
+             ePublicInferred = AtDeploymentTarget(), // FIXME: Inferred type should be diagnosed
+             fPublicInferred = AfterDeploymentTarget(), // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+             gPublicInferred = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  @available(macOS 10.14.5, *)
+  public var aPublicInferredAvailBetween = NoAvailable(),
+             bPublicInferredAvailBetween = BeforeInliningTarget(),
+             cPublicInferredAvailBetween = AtInliningTarget(),
+             dPublicInferredAvailBetween = BetweenTargets(),
+             ePublicInferredAvailBetween = AtDeploymentTarget(), // FIXME: Inferred type should be diagnosed
+             fPublicInferredAvailBetween = AfterDeploymentTarget(), // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+             gPublicInferredAvailBetween = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+
+  // Property initializers are not exposed.
+  public var aPublicInit: Any = NoAvailable(),
+             bPublicInit: Any = BeforeInliningTarget(),
+             cPublicInit: Any = AtInliningTarget(),
+             dPublicInit: Any = BetweenTargets(),
+             ePublicInit: Any = AtDeploymentTarget(),
+             fPublicInit: Any = AfterDeploymentTarget(), // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+             gPublicInit: Any = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  @available(macOS 10.14.5, *)
+  public var  aPublicInitAvailBetween: Any = {
+                if #available(macOS 11, *) {
+                  return NoAvailable(AfterDeploymentTarget())
+                } else {
+                  return NoAvailable(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+                }
+              }(),
+              bPublicInitAvailBetween: Any = {
+                if #available(macOS 11, *) {
+                  return BeforeInliningTarget(AfterDeploymentTarget())
+                } else {
+                  return BeforeInliningTarget(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+                }
+              }(),
+              cPublicInitAvailBetween: Any = {
+                if #available(macOS 11, *) {
+                  return AtInliningTarget(AfterDeploymentTarget())
+                } else {
+                  return AtInliningTarget(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+                }
+              }(),
+              dPublicInitAvailBetween: Any = {
+                if #available(macOS 11, *) {
+                  return BetweenTargets(AfterDeploymentTarget())
+                } else {
+                  return BetweenTargets(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+                }
+              }(),
+              ePublicInitAvailBetween: Any = {
+                if #available(macOS 11, *) {
+                  return AtDeploymentTarget(AfterDeploymentTarget())
+                } else {
+                  return AtDeploymentTarget(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+                }
+              }(),
+              fPublicInitAvailBetween: Any = {
+                if #available(macOS 11, *) {
+                  return AfterDeploymentTarget()
+                } else {
+                  return AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+                }
+              }()
+
+  // Internal declarations are not exposed.
+  var aInternal: NoAvailable = .init(),
+      bInternal: BeforeInliningTarget = .init(),
+      cInternal: AtInliningTarget = .init(),
+      dInternal: BetweenTargets = .init(),
+      eInternal: AtDeploymentTarget = .init(),
+      fInternal: AfterDeploymentTarget = .init(), // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+      gInternal: ObsoletedBetweenTargets = .init() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  @available(macOS 10.14, *)
+  public internal(set) var internalSetter: Void {
+    @inlinable get {
+      // Public inlinable getter acts like @inlinable
+      _ = NoAvailable()
+      _ = BeforeInliningTarget()
+      _ = AtInliningTarget()
+      _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
+      _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
+      _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+      _ = ObsoletedBetweenTargets()
+
+      if #available(macOS 10.15, *) {
+        _ = AtDeploymentTarget()
+      }
+      if #available(macOS 11, *) {
+        _ = AfterDeploymentTarget()
+      }
+    }
+    set {
+      // Private setter acts like non-inlinable
+      _ = NoAvailable()
+      _ = BeforeInliningTarget()
+      _ = AtInliningTarget()
+      _ = BetweenTargets()
+      _ = AtDeploymentTarget()
+      _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+      _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+      if #available(macOS 11, *) {
+        _ = AfterDeploymentTarget()
+      }
+    }
+  }
+  
+  public var block: () -> () = {
+    // The body of a block assigned to a public property acts like non-@inlinable
+    _ = NoAvailable()
+    _ = BeforeInliningTarget()
+    _ = AtInliningTarget()
+    _ = BetweenTargets()
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
+    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+    if #available(macOS 11, *) {
+      _ = AfterDeploymentTarget()
+    }
+  }
+}
+
+public struct PublicStructWithWrappers { // expected-note 4 {{add '@available' attribute}}
+  // The property type is inferred from the initializer expression. The
+  // expressions themselves will not be exposed.
+  @PropertyWrapper public var aExplicitInit = NoAvailable()
+  @PropertyWrapper public var bExplicitInit = BeforeInliningTarget()
+  @PropertyWrapper public var cExplicitInit = AtInliningTarget()
+  @PropertyWrapper public var dExplicitInit = BetweenTargets() // FIXME: Inferred type should be diagnosed
+  @PropertyWrapper public var eExplicitInit = AtDeploymentTarget() // FIXME: Inferred type should be diagnosed
+  @PropertyWrapper public var fExplicitInit = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+  
+  // The property type is inferred from the initializer expression. The
+  // expressions themselves will not be exposed.
+  @PropertyWrapper(NoAvailable()) public var aExplicitInitAlt
+  @PropertyWrapper(BeforeInliningTarget()) public var bExplicitInitAlt
+  @PropertyWrapper(AtInliningTarget()) public var cExplicitInitAlt
+  @PropertyWrapper(BetweenTargets()) public var dExplicitInitAlt  // FIXME: Inferred type should be diagnosed
+  @PropertyWrapper(AtDeploymentTarget()) public var ePExplicitInitAlt  // FIXME: Inferred type should be diagnosed
+  @PropertyWrapper(AfterDeploymentTarget()) public var fExplicitInitAlt // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  // The property type is explicitly `Any` and the initializer expressions are
+  // not exposed.
+  @PropertyWrapper public var aAny: Any = NoAvailable()
+  @PropertyWrapper public var bAny: Any = BeforeInliningTarget()
+  @PropertyWrapper public var cAny: Any = AtInliningTarget()
+  @PropertyWrapper public var dAny: Any = BetweenTargets()
+  @PropertyWrapper public var eAny: Any = AtDeploymentTarget()
+  @PropertyWrapper public var fAny: Any = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  // The property type is explicitly `Any` and the initializer expressions are
+  // not exposed.
+  @PropertyWrapper(NoAvailable()) public var aAnyAlt: Any
+  @PropertyWrapper(BeforeInliningTarget()) public var bAnyAlt: Any
+  @PropertyWrapper(AtInliningTarget()) public var cAnyAlt: Any
+  @PropertyWrapper(BetweenTargets()) public var dAnyAlt: Any
+  @PropertyWrapper(AtDeploymentTarget()) public var eAnyAlt: Any
+  @PropertyWrapper(AfterDeploymentTarget()) public var fAnyAlt: Any // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+}
+
+@frozen public struct FrozenPublicStruct { // expected-note 9 {{add '@available' attribute}}
+  // Public declarations are exposed.
+  public var aPublic: NoAvailable,
+             bPublic: BeforeInliningTarget,
+             cPublic: AtInliningTarget,
+             dPublic: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+             ePublic: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+             fPublic: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  // Property initializers are exposed in frozen structs.
+  public var aPublicInit: Any = NoAvailable(),
+             bPublicInit: Any = BeforeInliningTarget(),
+             cPublicInit: Any = AtInliningTarget(),
+             dPublicInit: Any = BetweenTargets(), // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+             ePublicInit: Any = AtDeploymentTarget(), // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+             fPublicInit: Any = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  // Internal declarations are also exposed in frozen structs.
+  var aInternal: NoAvailable = .init(),
+      bInternal: BeforeInliningTarget = .init(),
+      cInternal: AtInliningTarget = .init(),
+      dInternal: BetweenTargets = .init(), // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+      eInternal: AtDeploymentTarget = .init(), // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+      fInternal: AfterDeploymentTarget = .init() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+}
+
+@available(macOS, unavailable)
+public struct UnavailablePublicStruct {
+  public var aPublic: NoAvailable,
+             bPublic: BeforeInliningTarget,
+             cPublic: AtInliningTarget,
+             dPublic: BetweenTargets,
+             ePublic: AtDeploymentTarget,
+             fPublic: AfterDeploymentTarget,
+             gPublic: Unavailable
+
+  public var aPublicInit: Any = NoAvailable(),
+             bPublicInit: Any = BeforeInliningTarget(),
+             cPublicInit: Any = AtInliningTarget(),
+             dPublicInit: Any = BetweenTargets(),
+             ePublicInit: Any = AtDeploymentTarget(),
+             fPublicInit: Any = AfterDeploymentTarget(),
+             gPublicInit: Any = Unavailable()
+
+  var aInternal: NoAvailable = .init(),
+      bInternal: BeforeInliningTarget = .init(),
+      cInternal: AtInliningTarget = .init(),
+      dInternal: BetweenTargets = .init(),
+      eInternal: AtDeploymentTarget = .init(),
+      fInternal: AfterDeploymentTarget = .init(),
+      gInternal: Unavailable = .init()
+}
+
+@_spi(Private)
+public struct SPIStruct { // expected-note 3 {{add '@available' attribute}}
+  public var aPublic: NoAvailable,
+             bPublic: BeforeInliningTarget,
+             cPublic: AtInliningTarget,
+             dPublic: BetweenTargets,
+             ePublic: AtDeploymentTarget,
+             fPublic: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  public var aPublicInit: Any = NoAvailable(),
+             bPublicInit: Any = BeforeInliningTarget(),
+             cPublicInit: Any = AtInliningTarget(),
+             dPublicInit: Any = BetweenTargets(),
+             ePublicInit: Any = AtDeploymentTarget(),
+             fPublicInit: Any = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  var aInternal: NoAvailable = .init(),
+      bInternal: BeforeInliningTarget = .init(),
+      cInternal: AtInliningTarget = .init(),
+      dInternal: BetweenTargets = .init(),
+      eInternal: AtDeploymentTarget = .init(),
+      fInternal: AfterDeploymentTarget = .init() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+}
+
+internal struct InternalStruct { // expected-note 2 {{add '@available' attribute}}
+  // Internal declarations act like non-inlinable.
+  var aInternal: NoAvailable = .init(),
+      bInternal: BeforeInliningTarget = .init(),
+      cInternal: AtInliningTarget = .init(),
+      dInternal: BetweenTargets = .init(),
+      eInternal: AtDeploymentTarget = .init(),
+      fInternal: AfterDeploymentTarget = .init() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  @PropertyWrapper(NoAvailable()) var aWrapped: Any
+  @PropertyWrapper(BeforeInliningTarget()) var bWrapped: Any
+  @PropertyWrapper(AtInliningTarget()) var cWrapped: Any
+  @PropertyWrapper(BetweenTargets()) var dWrapped: Any
+  @PropertyWrapper(AtDeploymentTarget()) var eWrapped: Any
+  @PropertyWrapper(AfterDeploymentTarget()) var fWrapped: Any // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+}
+
+
+// MARK: - Extensions
+
+//
+// Extensions are externally visible if they extend a public type and (1) have
+// public members or (2) declare a conformance to a public protocol.
+//
+// Extensions without explicit availability that are externally visible use an
+// implied floor of either the availability of the extended type or the
+// deployment target, whichever is more available. This is a special rule
+// designed as a convenience to library authors who have written quite a bit of
+// code without annotating availability on their extensions and getting away
+// with it because previously the deployment target was always used as the
+// floor.
+//
+// Extensions without explicit availability that are not visible externally are
+// checked using an implied floor of the deployment target.
+//
+
+
+// MARK: Extensions on NoAvailable
+
+extension NoAvailable {}
+
+extension NoAvailable { // expected-note {{add '@available' attribute to enclosing extension}}
+  func internalFuncInExtension( // expected-note {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+extension NoAvailable { // expected-note 3 {{add '@available' attribute to enclosing extension}}
+  public func publicFuncInExtension( // expected-note 3 {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+    _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets,
+  ) {}
+}
+
+// MARK: Extensions on BetweenTargets
+
+extension BetweenTargets {}
+
+extension BetweenTargets { // expected-note {{add '@available' attribute to enclosing extension}}
+  func internalFuncInExtension( // expected-note {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+extension BetweenTargets { // expected-note 2 {{add '@available' attribute to enclosing extension}}
+  public func publicFuncInExtension( // expected-note 2 {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+@available(iOS 8.0, *)
+extension BetweenTargets { // expected-note 2 {{add '@available' attribute to enclosing extension}}
+  public func publicFuncInExtensionWithExplicitiOSAvailability( // expected-note 2 {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+@available(swift 5)
+extension BetweenTargets { // expected-note 2 {{add '@available' attribute to enclosing extension}}
+  public func publicFuncInExtensionWithExplicitSwiftAvailability( // expected-note 2 {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+@available(macOS 10.15, *)
+extension BetweenTargets {
+  public func publicFuncInExtensionWithExplicitAvailability( // expected-note {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+extension BetweenTargets { // expected-note {{add '@available' attribute to enclosing extension}}
+  @available(macOS 10.15, *)
+  public func publicFuncWithExplicitAvailabilityInExtension(
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+@_spi(Private)
+extension BetweenTargets { // expected-note {{add '@available' attribute to enclosing extension}}
+  public func inheritedSPIFuncInExtension( // expected-note {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+@available(macOS, unavailable)
+extension BetweenTargets {
+  public func inheritsUnavailableFuncInExtension(
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget,
+    _: ObsoletedBetweenTargets,
+    _: Unavailable
+  ) {}
+}
+
+// This extension is explicitly more available than BetweenTargets but because
+// it only contains internal members, the availability floor is still the
+// deployment target.
+@available(macOS 10.10, *)
+extension BetweenTargets {
+  func internalFuncInExcessivelyAvailableExtension() {}
+}
+
+extension BetweenTargets {
+  @available(macOS 10.10, *) // expected-warning {{instance method cannot be more available than enclosing scope}}
+  func excessivelyAvailableInternalFuncInExtension() {}
+}
+
+@available(macOS 10.10, *)
+extension BetweenTargets { // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  public func publicFuncInExcessivelyAvailableExtension() {}
+}
+
+// MARK: Extensions on BetweenTargetsInternal
+
+// Same availability as BetweenTargets but internal instead of public.
+@available(macOS 10.14.5, *)
+internal struct BetweenTargetsInternal {}
+
+extension BetweenTargetsInternal {}
+
+extension BetweenTargetsInternal { // expected-note {{add '@available' attribute to enclosing extension}}
+  func internalFuncInExtension( // expected-note {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+extension BetweenTargetsInternal { // expected-note {{add '@available' attribute to enclosing extension}}
+  public func publicFuncInExtension( // expected-note {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+// MARK: Extensions on AfterDeploymentTarget
+
+// expected-error@+1 {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note@+1 {{add '@available' attribute to enclosing extension}}
+extension AfterDeploymentTarget {}
+
+// expected-error@+1 {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+extension AfterDeploymentTarget { // expected-note 2 {{add '@available' attribute to enclosing extension}}
+  func internalFuncInExtension( // expected-note {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+// expected-error@+1 {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+extension AfterDeploymentTarget { // expected-note 2 {{add '@available' attribute to enclosing extension}}
+  public func publicFuncInExtension( // expected-note {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+@available(macOS 11, *)
+extension AfterDeploymentTarget {
+  public func publicFuncInExtensionWithExplicitAvailability(
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget,
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+// MARK: Extensions on nested types
+
+@available(macOS 10.14.5, *)
+public enum BetweenTargetsEnum {
+  public struct Nested {}
+}
+
+extension BetweenTargetsEnum.Nested {}
+
+extension BetweenTargetsEnum.Nested { // expected-note {{add '@available' attribute to enclosing extension}}
+  func internalFuncInExtension( // expected-note {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget,
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+extension BetweenTargetsEnum.Nested { // expected-note 2 {{add '@available' attribute to enclosing extension}}
+  public func publicFuncInExtension( // expected-note 2 {{add '@available' attribute to enclosing instance method}}
+    _: NoAvailable,
+    _: BeforeInliningTarget,
+    _: AtInliningTarget,
+    _: BetweenTargets,
+    _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+    _: AfterDeploymentTarget, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+    _: ObsoletedBetweenTargets, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  ) {}
+}
+
+// MARK: Protocol conformances
+
+internal protocol InternalProto {}
+
+extension NoAvailable: InternalProto {}
+extension BeforeInliningTarget: InternalProto {}
+extension AtInliningTarget: InternalProto {}
+extension BetweenTargets: InternalProto {}
+extension AtDeploymentTarget: InternalProto {}
+extension AfterDeploymentTarget: InternalProto {} // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add '@available' attribute to enclosing extension}}
+extension ObsoletedBetweenTargets: InternalProto {} // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+public protocol PublicProto {}
+
+extension NoAvailable: PublicProto {}
+extension BeforeInliningTarget: PublicProto {}
+extension AtInliningTarget: PublicProto {}
+extension BetweenTargets: PublicProto {}
+extension AtDeploymentTarget: PublicProto {}
+extension AfterDeploymentTarget: PublicProto {} // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add '@available' attribute to enclosing extension}}
+extension ObsoletedBetweenTargets: PublicProto {}
+
+
+// MARK: - Associated types
+
+public protocol NoAvailableProtoWithAssoc { // expected-note 3 {{add '@available' attribute to enclosing protocol}}
+  associatedtype A: NoAvailableProto
+  associatedtype B: BeforeInliningTargetProto
+  associatedtype C: AtInliningTargetProto
+  associatedtype D: BetweenTargetsProto // expected-error {{'BetweenTargetsProto' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype E: AtDeploymentTargetProto // expected-error {{'AtDeploymentTargetProto' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype G: ObsoletedBetweenTargetsProto
+}
+
+@available(macOS 10.9, *)
+public protocol BeforeInliningTargetProtoWithAssoc {
+  associatedtype A: NoAvailableProto
+  associatedtype B: BeforeInliningTargetProto
+  associatedtype C: AtInliningTargetProto
+  associatedtype D: BetweenTargetsProto // expected-error {{'BetweenTargetsProto' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype E: AtDeploymentTargetProto // expected-error {{'AtDeploymentTargetProto' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype G: ObsoletedBetweenTargetsProto
+}
+
+@available(macOS 10.10, *)
+public protocol AtInliningTargetProtoWithAssoc {
+  associatedtype A: NoAvailableProto
+  associatedtype B: BeforeInliningTargetProto
+  associatedtype C: AtInliningTargetProto
+  associatedtype D: BetweenTargetsProto // expected-error {{'BetweenTargetsProto' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype E: AtDeploymentTargetProto // expected-error {{'AtDeploymentTargetProto' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype G: ObsoletedBetweenTargetsProto
+}
+
+@available(macOS 10.14.5, *)
+public protocol BetweenTargetsProtoWithAssoc {
+  associatedtype A: NoAvailableProto
+  associatedtype B: BeforeInliningTargetProto
+  associatedtype C: AtInliningTargetProto
+  associatedtype D: BetweenTargetsProto
+  associatedtype E: AtDeploymentTargetProto // expected-error {{'AtDeploymentTargetProto' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype G: ObsoletedBetweenTargetsProto // expected-error {{'ObsoletedBetweenTargetsProto' is unavailable in macOS}}
+}
+
+@available(macOS 10.15, *)
+public protocol AtDeploymentTargetProtoWithAssoc {
+  associatedtype A: NoAvailableProto
+  associatedtype B: BeforeInliningTargetProto
+  associatedtype C: AtInliningTargetProto
+  associatedtype D: BetweenTargetsProto
+  associatedtype E: AtDeploymentTargetProto
+  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype G: ObsoletedBetweenTargetsProto // expected-error {{'ObsoletedBetweenTargetsProto' is unavailable in macOS}}
+}
+
+@available(macOS 11, *)
+public protocol AfterDeploymentTargetProtoWithAssoc {
+  associatedtype A: NoAvailableProto
+  associatedtype B: BeforeInliningTargetProto
+  associatedtype C: AtInliningTargetProto
+  associatedtype D: BetweenTargetsProto
+  associatedtype E: AtDeploymentTargetProto
+  associatedtype F: AfterDeploymentTargetProto
+  associatedtype G: ObsoletedBetweenTargetsProto // expected-error {{'ObsoletedBetweenTargetsProto' is unavailable in macOS}}
+}
+
+@available(macOS, unavailable)
+public protocol UnavailableProtoWithAssoc {
+  associatedtype A: NoAvailableProto
+  associatedtype B: BeforeInliningTargetProto
+  associatedtype C: AtInliningTargetProto
+  associatedtype D: BetweenTargetsProto
+  associatedtype E: AtDeploymentTargetProto
+  associatedtype F: AfterDeploymentTargetProto
+  associatedtype G: ObsoletedBetweenTargetsProto
+  associatedtype H: UnavailableProto
+}
+
+@_spi(Private)
+public protocol SPINoAvailableProtoWithAssoc { // expected-note 1 {{add '@available' attribute to enclosing protocol}}
+  associatedtype A: NoAvailableProto
+  associatedtype B: BeforeInliningTargetProto
+  associatedtype C: AtInliningTargetProto
+  associatedtype D: BetweenTargetsProto
+  associatedtype E: AtDeploymentTargetProto
+  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
+  // expected-note@-1{{add '@available' attribute to enclosing associated type}}
+  associatedtype G: ObsoletedBetweenTargetsProto // expected-error {{'ObsoletedBetweenTargetsProto' is unavailable in macOS}}
+}
+
+// MARK: - Type aliases
+
+public enum PublicNoAvailableEnumWithTypeAliases { // expected-note 3 {{add '@available' attribute to enclosing enum}}
+  public typealias A = NoAvailable
+  public typealias B = BeforeInliningTarget
+  public typealias C = AtInliningTarget
+  public typealias D = BetweenTargets // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add '@available' attribute to enclosing type alias}}
+  public typealias E = AtDeploymentTarget // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add '@available' attribute to enclosing type alias}}
+  public typealias F = AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add '@available' attribute to enclosing type alias}}
+  public typealias G = ObsoletedBetweenTargets
+}
+
+@available(macOS, unavailable)
+public enum UnavailableEnumWithTypeAliases {
+  public typealias A = NoAvailable
+  public typealias B = BeforeInliningTarget
+  public typealias C = AtInliningTarget
+  public typealias D = BetweenTargets
+  public typealias E = AtDeploymentTarget
+  public typealias F = AfterDeploymentTarget
+  public typealias G = ObsoletedBetweenTargets
+  public typealias H = Unavailable
+}
+
+@_spi(Private)
+public enum SPIEnumWithTypeAliases { // expected-note 1 {{add '@available' attribute to enclosing enum}}
+  public typealias A = NoAvailable
+  public typealias B = BeforeInliningTarget
+  public typealias C = AtInliningTarget
+  public typealias D = BetweenTargets
+  public typealias E = AtDeploymentTarget
+  public typealias F = AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add '@available' attribute to enclosing type alias}}
+  public typealias G = ObsoletedBetweenTargets // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+}
+
+enum InternalNoAvailableEnumWithTypeAliases { // expected-note {{add '@available' attribute to enclosing enum}}
+  public typealias A = NoAvailable
+  public typealias B = BeforeInliningTarget
+  public typealias C = AtInliningTarget
+  public typealias D = BetweenTargets
+  public typealias E = AtDeploymentTarget
+  public typealias F = AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add '@available' attribute to enclosing type alias}}
+  public typealias G = ObsoletedBetweenTargets // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+}
+
+// MARK: - Enums with payloads
+
+public enum PublicNoAvailableEnumWithPayloads { // expected-note 5 {{add '@available' attribute to enclosing enum}}
+  case aNoAvailable(NoAvailable),
+       bNoAvailable(BeforeInliningTarget),
+       cNoAvailable(AtInliningTarget),
+       dNoAvailable(BetweenTargets), // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+       eNoAvailable(AtDeploymentTarget), // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+       fNoAvailable(AfterDeploymentTarget), // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+       gNoAvailable(ObsoletedBetweenTargets)
+
+  @available(macOS, introduced: 10.15)
+  case aAtDeploymentTarget(NoAvailable),
+       bAtDeploymentTarget(BeforeInliningTarget),
+       cAtDeploymentTarget(AtInliningTarget),
+       dAtDeploymentTarget(BetweenTargets),
+       eAtDeploymentTarget(AtDeploymentTarget),
+       fAtDeploymentTarget(AfterDeploymentTarget), // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+       gAtDeploymentTarget(ObsoletedBetweenTargets) // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+  @_spi(Private)
+  case aSPI(NoAvailable),
+       bSPI(BeforeInliningTarget),
+       cSPI(AtInliningTarget),
+       dSPI(BetweenTargets),
+       eSPI(AtDeploymentTarget),
+       fSPI(AfterDeploymentTarget), // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+       gSPI(ObsoletedBetweenTargets) // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+
+
+  @available(macOS, unavailable)
+  case aUnavailable(NoAvailable),
+       bUnavailable(BeforeInliningTarget),
+       cUnavailable(AtInliningTarget),
+       dUnavailable(BetweenTargets),
+       eUnavailable(AtDeploymentTarget),
+       fUnavailable(AfterDeploymentTarget),
+       gUnavailable(ObsoletedBetweenTargets)
+}
+
+// MARK: - Class inheritance
+
+// FIXME: Duplicate 'add @available' emitted when classes are nested in a decl
+
+public enum NoAvailableEnumWithClasses {
+  public class InheritsNoAvailable: NoAvailableClass {}
+  public class InheritsBeforeInliningTarget: BeforeInliningTargetClass {}
+  public class InheritsAtInliningTarget: AtInliningTargetClass {}
+  public class InheritsBetweenTargets: BetweenTargetsClass {} // expected-error {{'BetweenTargetsClass' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note 2 {{add '@available' attribute to enclosing class}}
+  public class InheritsAtDeploymentTarget: AtDeploymentTargetClass {} // expected-error {{'AtDeploymentTargetClass' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note 2 {{add '@available' attribute to enclosing class}}
+  public class InheritsAfterDeploymentTarget: AfterDeploymentTargetClass {} // expected-error {{'AfterDeploymentTargetClass' is only available in macOS 11 or newer}} expected-note 2 {{add '@available' attribute to enclosing class}}
+  public class InheritsObsoletedBetweenTargetsClass: ObsoletedBetweenTargetsClass {}
+
+  @usableFromInline
+  class UFIInheritsBetweenTargets: BetweenTargetsClass {} // expected-error {{'BetweenTargetsClass' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note 2 {{add '@available' attribute to enclosing class}}
+}
+
+@_spi(Private)
+public enum SPIEnumWithClasses {
+  public class InheritsNoAvailable: NoAvailableClass {}
+  public class InheritsBeforeInliningTarget: BeforeInliningTargetClass {}
+  public class InheritsAtInliningTarget: AtInliningTargetClass {}
+  public class InheritsBetweenTargets: BetweenTargetsClass {}
+  public class InheritsAtDeploymentTarget: AtDeploymentTargetClass {}
+  // FIXME: Duplicate 'add @available' note is emitted
+  public class InheritsAfterDeploymentTarget: AfterDeploymentTargetClass {} // expected-error {{'AfterDeploymentTargetClass' is only available in}} expected-note 2 {{add '@available' attribute to enclosing class}}
+  public class InheritsObsoletedBetweenTargetsClass: ObsoletedBetweenTargetsClass {} // expected-error {{'ObsoletedBetweenTargetsClass' is unavailable in macOS}}
+
+}
+
+@available(macOS, unavailable)
+public enum UnavailableEnumWithClasses {
+  public class InheritsNoAvailable: NoAvailableClass {}
+  public class InheritsBeforeInliningTarget: BeforeInliningTargetClass {}
+  public class InheritsAtInliningTarget: AtInliningTargetClass {}
+  public class InheritsBetweenTargets: BetweenTargetsClass {}
+  public class InheritsAtDeploymentTarget: AtDeploymentTargetClass {}
+  public class InheritsAfterDeploymentTarget: AfterDeploymentTargetClass {}
+  public class InheritsObsoletedBetweenTargetsClass: ObsoletedBetweenTargetsClass {}
+  public class InheritsUnavailable: UnavailableClass {}
+}
+
+// MARK: - Overrides
+
+public class Base {
+  @available(macOS 10.9, *)
+  public func beforeInliningTargetMethod() {} // expected-note 3 {{overridden declaration is here}}
+
+  @available(macOS 10.10, *)
+  public func atInliningTargetMethod() {}// expected-note 3 {{overridden declaration is here}}
+
+  @available(macOS 10.14.5, *)
+  public func betweenTargetsMethod() {}// expected-note 3 {{overridden declaration is here}}
+
+  @available(macOS 10.15, *)
+  public func atDeploymentTargetMethod() {}// expected-note 2 {{overridden declaration is here}}
+
+  @available(macOS 11, *)
+  public func afterDeploymentTargetMethod() {}// expected-note {{overridden declaration is here}}
+
+  @available(macOS, obsoleted: 10.14.5)
+  public func obsoletedBetweenTargetsMethod() {} // expected-note 3 {{overridden declaration is here}}
+  // expected-note@-1 * {{'obsoletedBetweenTargetsMethod()' has been explicitly marked unavailable here}}
+}
+
+public class DerivedNoAvailable: Base {
+  public override func beforeInliningTargetMethod() {}
+  public override func atInliningTargetMethod() {}
+  public override func betweenTargetsMethod() {}
+  public override func atDeploymentTargetMethod() {}
+  public override func afterDeploymentTargetMethod() {}
+  public override func obsoletedBetweenTargetsMethod() {}
+}
+
+@available(macOS 10.9, *)
+public class DerivedBeforeInliningTarget: Base {
+  @available(macOS 10.9, *)
+  public override func beforeInliningTargetMethod() {}
+  @available(macOS 10.9, *)
+  public override func atInliningTargetMethod() {}
+  @available(macOS 10.9, *)
+  public override func betweenTargetsMethod() {}
+  @available(macOS 10.9, *)
+  public override func atDeploymentTargetMethod() {}
+  @available(macOS 10.9, *)
+  public override func afterDeploymentTargetMethod() {}
+  @available(macOS 10.9, *)
+  public override func obsoletedBetweenTargetsMethod() {}
+}
+
+@available(macOS 10.10, *)
+public class DerivedAtInliningTarget: Base {
+  @available(macOS 10.10, *)
+  public override func beforeInliningTargetMethod() {}
+  @available(macOS 10.10, *)
+  public override func atInliningTargetMethod() {}
+  @available(macOS 10.10, *)
+  public override func betweenTargetsMethod() {}
+  @available(macOS 10.10, *)
+  public override func atDeploymentTargetMethod() {}
+  @available(macOS 10.10, *)
+  public override func afterDeploymentTargetMethod() {}
+  @available(macOS 10.10, *)
+  public override func obsoletedBetweenTargetsMethod() {}
+}
+
+@available(macOS 10.14.5, *)
+public class DerivedBetweenTargets: Base {
+  @available(macOS 10.14.5, *)
+  public override func beforeInliningTargetMethod() {}
+  @available(macOS 10.14.5, *)
+  public override func atInliningTargetMethod() {}
+  @available(macOS 10.14.5, *)
+  public override func betweenTargetsMethod() {}
+  @available(macOS 10.14.5, *)
+  public override func atDeploymentTargetMethod() {}
+  @available(macOS 10.14.5, *)
+  public override func afterDeploymentTargetMethod() {}
+  @available(macOS 10.14.5, *)
+  public override func obsoletedBetweenTargetsMethod() {} // expected-error {{cannot override 'obsoletedBetweenTargetsMethod' which has been marked unavailable}}
+}
+
+@available(macOS 10.15, *)
+public class DerivedAtDeploymentTarget: Base {
+  @available(macOS 10.15, *)
+  public override func beforeInliningTargetMethod() {}
+  @available(macOS 10.15, *)
+  public override func atInliningTargetMethod() {}
+  @available(macOS 10.15, *)
+  public override func betweenTargetsMethod() {}
+  @available(macOS 10.15, *)
+  public override func atDeploymentTargetMethod() {}
+  @available(macOS 10.15, *)
+  public override func afterDeploymentTargetMethod() {}
+  @available(macOS 10.15, *)
+  public override func obsoletedBetweenTargetsMethod() {} // expected-error {{cannot override 'obsoletedBetweenTargetsMethod' which has been marked unavailable}}
+}
+
+@available(macOS 11, *)
+public class DerivedAfterDeploymentTarget: Base {
+  @available(macOS 11, *)
+  public override func beforeInliningTargetMethod() {}
+  @available(macOS 11, *)
+  public override func atInliningTargetMethod() {}
+  @available(macOS 11, *)
+  public override func betweenTargetsMethod() {}
+  @available(macOS 11, *)
+  public override func atDeploymentTargetMethod() {}
+  @available(macOS 11, *)
+  public override func afterDeploymentTargetMethod() {}
+  @available(macOS 11, *)
+  public override func obsoletedBetweenTargetsMethod() {} // expected-error {{cannot override 'obsoletedBetweenTargetsMethod' which has been marked unavailable}}
+}
+
+public class DerivedAtDeploymentTargetOverrides: Base {
+  @available(macOS 10.15, *)
+  public override func beforeInliningTargetMethod() {} // expected-error {{overriding 'beforeInliningTargetMethod' must be as available as declaration it overrides}}
+
+  @available(macOS 10.15, *)
+  public override func atInliningTargetMethod() {} // expected-error {{overriding 'atInliningTargetMethod' must be as available as declaration it overrides}}
+
+  @available(macOS 10.15, *)
+  public override func betweenTargetsMethod() {} // expected-error {{overriding 'betweenTargetsMethod' must be as available as declaration it overrides}}
+
+  @available(macOS 10.15, *)
+  public override func atDeploymentTargetMethod() {}
+
+  @available(macOS 10.15, *)
+  public override func afterDeploymentTargetMethod() {}
+
+  @available(macOS 10.15, *)
+  public override func obsoletedBetweenTargetsMethod() {} // expected-error {{overriding 'obsoletedBetweenTargetsMethod' must be as available as declaration it overrides}}
+}
+
+public class DerivedFutureOverrides: Base {
+  @available(macOS 12, *)
+  public override func beforeInliningTargetMethod() {} // expected-error {{overriding 'beforeInliningTargetMethod' must be as available as declaration it overrides}}
+
+  @available(macOS 12, *)
+  public override func atInliningTargetMethod() {} // expected-error {{overriding 'atInliningTargetMethod' must be as available as declaration it overrides}}
+
+  @available(macOS 12, *)
+  public override func betweenTargetsMethod() {} // expected-error {{overriding 'betweenTargetsMethod' must be as available as declaration it overrides}}
+
+  @available(macOS 12, *)
+  public override func atDeploymentTargetMethod() {} // expected-error {{overriding 'atDeploymentTargetMethod' must be as available as declaration it overrides}}
+
+  @available(macOS 12, *)
+  public override func afterDeploymentTargetMethod() {} // expected-error {{overriding 'afterDeploymentTargetMethod' must be as available as declaration it overrides}}
+
+  @available(macOS 12, *)
+  public override func obsoletedBetweenTargetsMethod() {} // expected-error {{overriding 'obsoletedBetweenTargetsMethod' must be as available as declaration it overrides}}
+}
+
+extension AtDeploymentTarget {
+  public class DerivedAtDeploymentTargetOverrides: Base {
+    @available(macOS 10.15, *)
+    public override func beforeInliningTargetMethod() {}
+
+    @available(macOS 10.15, *)
+    public override func atInliningTargetMethod() {}
+
+    @available(macOS 10.15, *)
+    public override func betweenTargetsMethod() {}
+
+    @available(macOS 10.15, *)
+    public override func atDeploymentTargetMethod() {}
+
+    @available(macOS 10.15, *)
+    public override func afterDeploymentTargetMethod() {}
+
+    @available(macOS 10.15, *)
+    public override func obsoletedBetweenTargetsMethod() {} // expected-error {{cannot override 'obsoletedBetweenTargetsMethod' which has been marked unavailable}}
+  }
+
+  public class DerivedAfterDeploymentTargetOverrides: Base {
+    @available(macOS 11, *)
+    public override func beforeInliningTargetMethod() {} // expected-error {{overriding 'beforeInliningTargetMethod' must be as available as declaration it overrides}}
+
+    @available(macOS 11, *)
+    public override func atInliningTargetMethod() {} // expected-error {{overriding 'atInliningTargetMethod' must be as available as declaration it overrides}}
+
+    @available(macOS 11, *)
+    public override func betweenTargetsMethod() {} // expected-error {{overriding 'betweenTargetsMethod' must be as available as declaration it overrides}}
+
+    @available(macOS 11, *)
+    public override func atDeploymentTargetMethod() {} // expected-error {{overriding 'atDeploymentTargetMethod' must be as available as declaration it overrides}}
+
+    @available(macOS 11, *)
+    public override func afterDeploymentTargetMethod() {}
+
+    @available(macOS 11, *)
+    public override func obsoletedBetweenTargetsMethod() {} // expected-error {{overriding 'obsoletedBetweenTargetsMethod' must be as available as declaration it overrides}}
+  }
+}
diff --git a/test/Sema/availability_unavailable_overrides.swift b/test/Availability/availability_unavailable_overrides.swift
similarity index 94%
rename from test/Sema/availability_unavailable_overrides.swift
rename to test/Availability/availability_unavailable_overrides.swift
index 50e1365d26eef..a2e0e1353d440 100644
--- a/test/Sema/availability_unavailable_overrides.swift
+++ b/test/Availability/availability_unavailable_overrides.swift
@@ -56,8 +56,7 @@ func testAvailableOverrideOfUnavailableDecl() {
 
     override var computedPropertyWithUnavailableSet: Int {
       get { 0 }
-      // FIXME: Diagnostic should refer to "setter for 'computedPropertyWithUnavailableSet'" rather than '_'.
-      set {} // expected-error {{cannot override '_' which has been marked unavailable}}
+      set {} // expected-error {{cannot override setter for 'computedPropertyWithUnavailableSet' which has been marked unavailable}}
     }
   }
 
@@ -240,7 +239,6 @@ func testOverrideOfUnavailableDeclFromUnavailableDerivedType() {
   }
 }
 
-
 func testImplicitSuperInit() {
   // FIXME: The diagnostics for the implicit call to super.init() could be
   // relaxed since both initializers are unreachable and the developer cannot
@@ -257,3 +255,19 @@ func testImplicitSuperInit() {
     // expected-note@-2 {{call to unavailable initializer 'init()' from superclass 'Base' occurs implicitly at the end of this initializer}}
   }
 }
+
+func testUnavailableInSwiftOverrides() {
+  class Base {
+    func availableMethod() {}
+  }
+
+  class Derived1: Base {
+    @available(swift, introduced: 99)
+    override func availableMethod() {}
+  }
+
+  class Derived2: Base {
+    @available(swift, obsoleted: 1)
+    override func availableMethod() {}
+  }
+}
diff --git a/test/Sema/availability_unnecessary.swift b/test/Availability/availability_unnecessary.swift
similarity index 100%
rename from test/Sema/availability_unnecessary.swift
rename to test/Availability/availability_unnecessary.swift
diff --git a/test/Sema/availability_versions.swift b/test/Availability/availability_versions.swift
similarity index 91%
rename from test/Sema/availability_versions.swift
rename to test/Availability/availability_versions.swift
index 9ff8049e79101..42b85a3526a55 100644
--- a/test/Sema/availability_versions.swift
+++ b/test/Availability/availability_versions.swift
@@ -28,7 +28,7 @@ let ignored3: Int = globalFuncAvailableOn52() // expected-error {{'globalFuncAva
 
 // Functions without annotations should reflect the minimum deployment target.
 func functionWithoutAvailability() {
-      // expected-note@-1 5{{add @available attribute to enclosing global function}}
+      // expected-note@-1 5{{add '@available' attribute to enclosing global function}}
 
   defer {
     let _: Int = globalFuncAvailableOn10_9()
@@ -144,10 +144,10 @@ func globalFuncDeprecatedAndAvailableOn51() -> Int { return 51 }
 func globalFuncAvailableOn51Deprecated52() -> Int { return 51 }
 
 @available(OSX, introduced: 51, obsoleted: 52)
-func globalFuncAvailableOn51Obsoleted52() -> Int { return 51 }
+func globalFuncAvailableOn51Obsoleted52() -> Int { return 51 } // expected-note {{'globalFuncAvailableOn51Obsoleted52()' was obsoleted in macOS 52}}
 
 @available(OSX, unavailable, introduced: 51)
-func globalFuncUnavailableAndIntroducedOn51() -> Int { return 51 } // expected-note 2 {{'globalFuncUnavailableAndIntroducedOn51()' has been explicitly marked unavailable here}}
+func globalFuncUnavailableAndIntroducedOn51() -> Int { return 51 } // expected-note 3 {{'globalFuncUnavailableAndIntroducedOn51()' has been explicitly marked unavailable here}}
 
 let _ = globalFuncDeprecatedAndAvailableOn51() // expected-error {{'globalFuncDeprecatedAndAvailableOn51()' is only available in macOS 51 or newer}}
 // expected-note@-1 {{add 'if #available' version check}}
@@ -165,10 +165,18 @@ if #available(OSX 51, *) {
   let _ = globalFuncUnavailableAndIntroducedOn51() // expected-error {{'globalFuncUnavailableAndIntroducedOn51()' is unavailable in macOS}}
 }
 
+if #available(OSX 52, *) {
+  let _ = globalFuncDeprecatedAndAvailableOn51() // expected-warning {{'globalFuncDeprecatedAndAvailableOn51()' is deprecated in macOS}}
+  let _ = globalFuncAvailableOn51Deprecated52()
+  let _ = globalFuncAvailableOn51Obsoleted52() // expected-error {{'globalFuncAvailableOn51Obsoleted52()' is unavailable in macOS}}
+  let _ = globalFuncUnavailableAndIntroducedOn51() // expected-error {{'globalFuncUnavailableAndIntroducedOn51()' is unavailable in macOS}}
+}
+
+
 // Potentially unavailable methods
 
 class ClassWithPotentiallyUnavailableMethod {
-    // expected-note@-1 {{add @available attribute to enclosing class}}
+    // expected-note@-1 {{add '@available' attribute to enclosing class}}
 
   @available(OSX, introduced: 10.9)
   func methAvailableOn10_9() {}
@@ -180,7 +188,7 @@ class ClassWithPotentiallyUnavailableMethod {
   class func classMethAvailableOn51() {}
   
   func someOtherMethod() {
-    // expected-note@-1 {{add @available attribute to enclosing instance method}}
+    // expected-note@-1 {{add '@available' attribute to enclosing instance method}}
 
     methAvailableOn10_9()
     methAvailableOn51() // expected-error {{'methAvailableOn51()' is only available in macOS 51 or newer}}
@@ -189,7 +197,7 @@ class ClassWithPotentiallyUnavailableMethod {
 }
 
 func callPotentiallyUnavailableMethods(_ o: ClassWithPotentiallyUnavailableMethod) {
-      // expected-note@-1 2{{add @available attribute to enclosing global function}}
+      // expected-note@-1 2{{add '@available' attribute to enclosing global function}}
 
   let m10_9 = o.methAvailableOn10_9
   m10_9()
@@ -205,7 +213,7 @@ func callPotentiallyUnavailableMethods(_ o: ClassWithPotentiallyUnavailableMetho
 }
 
 func callPotentiallyUnavailableMethodsViaIUO(_ o: ClassWithPotentiallyUnavailableMethod!) {
-      // expected-note@-1 2{{add @available attribute to enclosing global function}}
+      // expected-note@-1 2{{add '@available' attribute to enclosing global function}}
 
   let m10_9 = o.methAvailableOn10_9
   m10_9()
@@ -222,7 +230,7 @@ func callPotentiallyUnavailableMethodsViaIUO(_ o: ClassWithPotentiallyUnavailabl
 }
 
 func callPotentiallyUnavailableClassMethod() {
-      // expected-note@-1 2{{add @available attribute to enclosing global function}}
+      // expected-note@-1 2{{add '@available' attribute to enclosing global function}}
 
   ClassWithPotentiallyUnavailableMethod.classMethAvailableOn51() // expected-error {{'classMethAvailableOn51()' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
@@ -234,9 +242,9 @@ func callPotentiallyUnavailableClassMethod() {
 }
 
 class SubClassWithPotentiallyUnavailableMethod : ClassWithPotentiallyUnavailableMethod {
-        // expected-note@-1 {{add @available attribute to enclosing class}}
+        // expected-note@-1 {{add '@available' attribute to enclosing class}}
   func someMethod() {
-        // expected-note@-1 {{add @available attribute to enclosing instance method}}
+        // expected-note@-1 {{add '@available' attribute to enclosing instance method}}
 
     methAvailableOn10_9()
     methAvailableOn51() // expected-error {{'methAvailableOn51()' is only available in macOS 51 or newer}}
@@ -245,10 +253,10 @@ class SubClassWithPotentiallyUnavailableMethod : ClassWithPotentiallyUnavailable
 }
 
 class SubClassOverridingPotentiallyUnavailableMethod : ClassWithPotentiallyUnavailableMethod {
-        // expected-note@-1 2{{add @available attribute to enclosing class}}
+        // expected-note@-1 2{{add '@available' attribute to enclosing class}}
 
   override func methAvailableOn51() {
-        // expected-note@-1 2{{add @available attribute to enclosing instance method}}
+        // expected-note@-1 2{{add '@available' attribute to enclosing instance method}}
     methAvailableOn10_9()
     super.methAvailableOn51() // expected-error {{'methAvailableOn51()' is only available in macOS 51 or newer}}
         // expected-note@-1 {{add 'if #available' version check}}
@@ -315,7 +323,7 @@ class ClassWithPotentiallyUnavailableOverloadedMethod {
 }
 
 func callPotentiallyUnavailableOverloadedMethod(_ o: ClassWithPotentiallyUnavailableOverloadedMethod) {
-      // expected-note@-1 {{add @available attribute to enclosing global function}}
+      // expected-note@-1 {{add '@available' attribute to enclosing global function}}
 
   o.overloadedMethod()
   o.overloadedMethod(0) // expected-error {{'overloadedMethod' is only available in macOS 51 or newer}}
@@ -325,7 +333,7 @@ func callPotentiallyUnavailableOverloadedMethod(_ o: ClassWithPotentiallyUnavail
 // Initializers
 
 class ClassWithPotentiallyUnavailableInitializer {
-    // expected-note@-1 {{add @available attribute to enclosing class}}
+    // expected-note@-1 {{add '@available' attribute to enclosing class}}
 
   @available(OSX, introduced: 10.9)
   required init() {  }
@@ -334,7 +342,7 @@ class ClassWithPotentiallyUnavailableInitializer {
   required init(_ val: Int) {  }
   
   convenience init(s: String) {
-        // expected-note@-1 {{add @available attribute to enclosing initializer}}
+        // expected-note@-1 {{add '@available' attribute to enclosing initializer}}
     
     self.init(5) // expected-error {{'init(_:)' is only available in macOS 51 or newer}}
         // expected-note@-1 {{add 'if #available' version check}}
@@ -347,7 +355,7 @@ class ClassWithPotentiallyUnavailableInitializer {
 }
 
 func callPotentiallyUnavailableInitializer() {
-      // expected-note@-1 2{{add @available attribute to enclosing global function}}
+      // expected-note@-1 2{{add '@available' attribute to enclosing global function}}
 
   _ = ClassWithPotentiallyUnavailableInitializer()
   _ = ClassWithPotentiallyUnavailableInitializer(5) // expected-error {{'init(_:)' is only available in macOS 51 or newer}}
@@ -368,10 +376,10 @@ class SuperWithWithPotentiallyUnavailableInitializer {
 }
 
 class SubOfClassWithPotentiallyUnavailableInitializer : SuperWithWithPotentiallyUnavailableInitializer {
-    // expected-note@-1 {{add @available attribute to enclosing class}}
+    // expected-note@-1 {{add '@available' attribute to enclosing class}}
 
   override init(_ val: Int) {
-        // expected-note@-1 {{add @available attribute to enclosing initializer}}
+        // expected-note@-1 {{add '@available' attribute to enclosing initializer}}
 
     super.init(5) // expected-error {{'init(_:)' is only available in macOS 51 or newer}}
         // expected-note@-1 {{add 'if #available' version check}}
@@ -390,7 +398,7 @@ class SubOfClassWithPotentiallyUnavailableInitializer : SuperWithWithPotentially
 // Properties
 
 class ClassWithPotentiallyUnavailableProperties {
-    // expected-note@-1 4{{add @available attribute to enclosing class}}
+    // expected-note@-1 4{{add '@available' attribute to enclosing class}}
 
   var nonLazyAvailableOn10_9Stored: Int = 9
 
@@ -438,7 +446,7 @@ class ClassWithPotentiallyUnavailableProperties {
   }
   
   var propWithSetterOnlyAvailableOn51 : Int {
-      // expected-note@-1 {{add @available attribute to enclosing property}}
+      // expected-note@-1 {{add '@available' attribute to enclosing property}}
     get {
       _ = globalFuncAvailableOn51() // expected-error {{'globalFuncAvailableOn51()' is only available in macOS 51 or newer}}
           // expected-note@-1 {{add 'if #available' version check}}
@@ -451,7 +459,7 @@ class ClassWithPotentiallyUnavailableProperties {
   }
   
   var propWithGetterOnlyAvailableOn51 : Int {
-      // expected-note@-1 {{add @available attribute to enclosing property}}
+      // expected-note@-1 {{add '@available' attribute to enclosing property}}
     @available(OSX, introduced: 51)
     get {
       _ = globalFuncAvailableOn51()
@@ -504,7 +512,7 @@ class ClassWithReferencesInInitializers {
 }
 
 func accessPotentiallyUnavailableProperties(_ o: ClassWithPotentiallyUnavailableProperties) {
-      // expected-note@-1 17{{add @available attribute to enclosing global function}}
+      // expected-note@-1 17{{add '@available' attribute to enclosing global function}}
   // Stored properties
   let _: Int = o.availableOn10_9Stored
   let _: Int = o.availableOn51Stored // expected-error {{'availableOn51Stored' is only available in macOS 51 or newer}}
@@ -639,7 +647,7 @@ enum CompassPoint {
 func functionTakingEnumIntroducedOn52(_ e: EnumIntroducedOn52) { }
 
 func useEnums() {
-      // expected-note@-1 3{{add @available attribute to enclosing global function}}
+      // expected-note@-1 3{{add '@available' attribute to enclosing global function}}
   let _: CompassPoint = .North // expected-error {{'CompassPoint' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
 
@@ -722,7 +730,7 @@ class ClassAvailableOn51 { // expected-note {{enclosing scope requires availabil
 }
 
 func classAvailability() {
-      // expected-note@-1 3{{add @available attribute to enclosing global function}}
+      // expected-note@-1 3{{add '@available' attribute to enclosing global function}}
   ClassAvailableOn10_9.someClassMethod()
   ClassAvailableOn51.someClassMethod() // expected-error {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
@@ -743,7 +751,7 @@ func classAvailability() {
 }
 
 func castingPotentiallyUnavailableClass(_ o : AnyObject) {
-      // expected-note@-1 3{{add @available attribute to enclosing global function}}
+      // expected-note@-1 3{{add '@available' attribute to enclosing global function}}
   let _ = o as! ClassAvailableOn51 // expected-error {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
 
@@ -772,7 +780,7 @@ class ClassWithGenericTypeParameter<T> { }
 class ClassWithTwoGenericTypeParameter<T, S> { }
 
 func classViaTypeParameter() {
-  // expected-note@-1 9{{add @available attribute to enclosing global function}}
+  // expected-note@-1 9{{add '@available' attribute to enclosing global function}}
   let _ : ClassAvailableOn51_Creatable = // expected-error {{'ClassAvailableOn51_Creatable' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
       create()
@@ -804,7 +812,7 @@ func classViaTypeParameter() {
 // Potentially unavailable class used in declarations
 
 class ClassWithDeclarationsOfPotentiallyUnavailableClasses {
-      // expected-note@-1 5{{add @available attribute to enclosing class}}
+      // expected-note@-1 5{{add '@available' attribute to enclosing class}}
 
   @available(OSX, introduced: 51)
   init() {}
@@ -818,14 +826,14 @@ class ClassWithDeclarationsOfPotentiallyUnavailableClasses {
   static var potentiallyUnavailableStaticPropertyOfOptionalPotentiallyUnavailableType: ClassAvailableOn51?
 
   func methodWithPotentiallyUnavailableParameterType(_ o : ClassAvailableOn51) { // expected-error {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
-      // expected-note@-1 {{add @available attribute to enclosing instance method}}
+      // expected-note@-1 {{add '@available' attribute to enclosing instance method}}
   }
   
   @available(OSX, introduced: 51)
   func potentiallyUnavailableMethodWithPotentiallyUnavailableParameterType(_ o : ClassAvailableOn51) {}
   
   func methodWithPotentiallyUnavailableReturnType() -> ClassAvailableOn51 { // expected-error {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
-      // expected-note@-1 2{{add @available attribute to enclosing instance method}}
+      // expected-note@-1 2{{add '@available' attribute to enclosing instance method}}
 
     return ClassAvailableOn51() // expected-error {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
@@ -846,7 +854,7 @@ class ClassWithDeclarationsOfPotentiallyUnavailableClasses {
   }
 
   func methodWithPotentiallyUnavailableLocalDeclaration() {
-      // expected-note@-1 {{add @available attribute to enclosing instance method}}
+      // expected-note@-1 {{add '@available' attribute to enclosing instance method}}
     let _ : ClassAvailableOn51 = methodWithPotentiallyUnavailableReturnType() // expected-error {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
   }
@@ -863,13 +871,13 @@ class ClassWithDeclarationsOfPotentiallyUnavailableClasses {
 }
 
 func referToPotentiallyUnavailableStaticProperty() {
-      // expected-note@-1 {{add @available attribute to enclosing global function}}
+      // expected-note@-1 {{add '@available' attribute to enclosing global function}}
   let _ = ClassWithDeclarationsOfPotentiallyUnavailableClasses.potentiallyUnavailableStaticPropertyOfPotentiallyUnavailableType // expected-error {{'potentiallyUnavailableStaticPropertyOfPotentiallyUnavailableType' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
 }
 
 class ClassExtendingPotentiallyUnavailableClass : ClassAvailableOn51 { // expected-error {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
-    // expected-note@-1 {{add @available attribute to enclosing class}}
+    // expected-note@-1 {{add '@available' attribute to enclosing class}}
 }
 
 @available(OSX, introduced: 51)
@@ -917,7 +925,6 @@ class SubWithLimitedMemberAvailability : SuperWithAlwaysAvailableMembers {
     get { return 9 }
     @available(OSX, introduced: 51)
     set(newVal) {} // expected-error {{overriding setter for 'setterShouldAlwaysBeAvailableProperty' must be as available as declaration it overrides}}
-    // This is a terrible diagnostic. rdar://problem/20427938
   }
 
   override var getterShouldAlwaysBeAvailableProperty: Int {
@@ -1011,7 +1018,7 @@ class SuperWithLimitedMemberAvailability {
 }
 
 class SubWithLargerMemberAvailability : SuperWithLimitedMemberAvailability {
-        // expected-note@-1 2{{add @available attribute to enclosing class}}
+        // expected-note@-1 2{{add '@available' attribute to enclosing class}}
   @available(OSX, introduced: 10.9)
   override func someMethod() {
     super.someMethod() // expected-error {{'someMethod()' is only available in macOS 51 or newer}}
@@ -1123,7 +1130,7 @@ class ClassAvailableOn10_9AdoptingProtocolAvailableOn51 : ProtocolAvailableOn51
 }
 
 func castToPotentiallyUnavailableProtocol() {
-      // expected-note@-1 2{{add @available attribute to enclosing global function}}
+      // expected-note@-1 2{{add '@available' attribute to enclosing global function}}
   let o: ClassAvailableOn10_9AdoptingProtocolAvailableOn51 = ClassAvailableOn10_9AdoptingProtocolAvailableOn51()
 
   let _: ProtocolAvailableOn51 = o // expected-error {{'ProtocolAvailableOn51' is only available in macOS 51 or newer}}
@@ -1148,7 +1155,7 @@ class UnavailableSubclassOfSomeGenericClassOfProtocolAvailableOn51 : SomeGeneric
 }
 
 func GenericWhereClause<T>(_ t: T) where T: ProtocolAvailableOn51 { // expected-error * {{'ProtocolAvailableOn51' is only available in macOS 51 or newer}}
-      // expected-note@-1 * {{add @available attribute to enclosing global function}}
+      // expected-note@-1 * {{add '@available' attribute to enclosing global function}}
 }
 
 @available(OSX, unavailable)
@@ -1156,22 +1163,22 @@ func UnavailableGenericWhereClause<T>(_ t: T) where T: ProtocolAvailableOn51 {
 }
 
 func GenericSignature<T : ProtocolAvailableOn51>(_ t: T) { // expected-error * {{'ProtocolAvailableOn51' is only available in macOS 51 or newer}}
-      // expected-note@-1 * {{add @available attribute to enclosing global function}}
+      // expected-note@-1 * {{add '@available' attribute to enclosing global function}}
 }
 
 @available(OSX, unavailable)
 func UnavailableGenericSignature<T : ProtocolAvailableOn51>(_ t: T) {
 }
 
-struct GenericType<T> { // expected-note {{add @available attribute to enclosing generic struct}}
+struct GenericType<T> { // expected-note {{add '@available' attribute to enclosing generic struct}}
   func nonGenericWhereClause() where T : ProtocolAvailableOn51 {} // expected-error {{'ProtocolAvailableOn51' is only available in macOS 51 or newer}}
-  // expected-note@-1 {{add @available attribute to enclosing instance method}}
+  // expected-note@-1 {{add '@available' attribute to enclosing instance method}}
   
   @available(OSX, unavailable)
   func unavailableNonGenericWhereClause() where T : ProtocolAvailableOn51 {}
 
   struct NestedType where T : ProtocolAvailableOn51 {} // expected-error {{'ProtocolAvailableOn51' is only available in macOS 51 or newer}}
-  // expected-note@-1 2{{add @available attribute to enclosing struct}}
+  // expected-note@-1 2{{add '@available' attribute to enclosing struct}}
   
   @available(OSX, unavailable)
   struct UnavailableNestedType where T : ProtocolAvailableOn51 {}
@@ -1180,7 +1187,7 @@ struct GenericType<T> { // expected-note {{add @available attribute to enclosing
 // Extensions
 
 extension ClassAvailableOn51 { } // expected-error {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
-    // expected-note@-1 {{add @available attribute to enclosing extension}}
+    // expected-note@-1 {{add '@available' attribute to enclosing extension}}
 
 @available(OSX, unavailable)
 extension ClassAvailableOn51 { }
@@ -1188,7 +1195,7 @@ extension ClassAvailableOn51 { }
 @available(OSX, introduced: 51)
 extension ClassAvailableOn51 {
   func m() {
-      // expected-note@-1 {{add @available attribute to enclosing instance method}}
+      // expected-note@-1 {{add '@available' attribute to enclosing instance method}}
     let _ = globalFuncAvailableOn51()
     let _ = globalFuncAvailableOn52() // expected-error {{'globalFuncAvailableOn52()' is only available in macOS 52 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
@@ -1230,7 +1237,7 @@ extension ClassToExtend { // expected-note 2 {{enclosing scope requires availabi
 }
 
 func usePotentiallyUnavailableExtension() {
-      // expected-note@-1 3{{add @available attribute to enclosing global function}}
+      // expected-note@-1 3{{add '@available' attribute to enclosing global function}}
   let o = ClassToExtend()
 
   o.extensionMethod() // expected-error {{'extensionMethod()' is only available in macOS 51 or newer}}
@@ -1391,7 +1398,7 @@ if let _ = injectToOptional(5), #available(OSX 51, *), // expected-note {{enclos
 // Tests for the guard control construct.
 
 func useGuardAvailable() {
-        // expected-note@-1 3{{add @available attribute to enclosing global function}}
+        // expected-note@-1 3{{add '@available' attribute to enclosing global function}}
   // Guard fallthrough should refine context
   guard #available(OSX 51, *) else { // expected-note {{enclosing scope here}}
     let _ = globalFuncAvailableOn51() // expected-error {{'globalFuncAvailableOn51()' is only available in macOS 51 or newer}}
@@ -1418,7 +1425,7 @@ func useGuardAvailable() {
 }
 
 func twoGuardsInSameBlock(_ p: Int) {
-        // expected-note@-1 {{add @available attribute to enclosing global function}}
+        // expected-note@-1 {{add '@available' attribute to enclosing global function}}
   if (p > 0) {
     guard #available(OSX 51, *) else { return }
 
@@ -1471,7 +1478,7 @@ let declForFixitAtTopLevel: ClassAvailableOn51? = nil
       // expected-note@-2 {{add 'if #available' version check}} {{1-54=if #available(macOS 51, *) {\n    let declForFixitAtTopLevel: ClassAvailableOn51? = nil\n} else {\n    // Fallback on earlier versions\n}}}
 
 func fixitForReferenceInGlobalFunction() {
-      // expected-note@-1 {{add @available attribute to enclosing global function}} {{1-1=@available(macOS 51, *)\n}}
+      // expected-note@-1 {{add '@available' attribute to enclosing global function}} {{1-1=@available(macOS 51, *)\n}}
   functionAvailableOn51()
       // expected-error@-1 {{'functionAvailableOn51()' is only available in macOS 51 or newer}}
       // expected-note@-2 {{add 'if #available' version check}} {{3-26=if #available(macOS 51, *) {\n      functionAvailableOn51()\n  } else {\n      // Fallback on earlier versions\n  }}}
@@ -1479,7 +1486,7 @@ func fixitForReferenceInGlobalFunction() {
 }
 
 public func fixitForReferenceInGlobalFunctionWithDeclModifier() {
-      // expected-note@-1 {{add @available attribute to enclosing global function}} {{1-1=@available(macOS 51, *)\n}}
+      // expected-note@-1 {{add '@available' attribute to enclosing global function}} {{1-1=@available(macOS 51, *)\n}}
   functionAvailableOn51()
       // expected-error@-1 {{'functionAvailableOn51()' is only available in macOS 51 or newer}}
       // expected-note@-2 {{add 'if #available' version check}} {{3-26=if #available(macOS 51, *) {\n      functionAvailableOn51()\n  } else {\n      // Fallback on earlier versions\n  }}}
@@ -1487,7 +1494,7 @@ public func fixitForReferenceInGlobalFunctionWithDeclModifier() {
 }
 
 func fixitForReferenceInGlobalFunctionWithAttribute() -> Never {
-    // expected-note@-1 {{add @available attribute to enclosing global function}} {{1-1=@available(macOS 51, *)\n}}
+    // expected-note@-1 {{add '@available' attribute to enclosing global function}} {{1-1=@available(macOS 51, *)\n}}
   _ = 0 // Avoid treating the call to functionAvailableOn51 as an implicit return
   functionAvailableOn51()
     // expected-error@-1 {{'functionAvailableOn51()' is only available in macOS 51 or newer}}
@@ -1499,16 +1506,16 @@ func takesAutoclosure(_ c : @autoclosure () -> ()) {
 }
 
 class ClassForFixit {
-        // expected-note@-1 12{{add @available attribute to enclosing class}} {{1-1=@available(macOS 51, *)\n}}
+        // expected-note@-1 12{{add '@available' attribute to enclosing class}} {{1-1=@available(macOS 51, *)\n}}
   func fixitForReferenceInMethod() {
-        // expected-note@-1 {{add @available attribute to enclosing instance method}} {{3-3=@available(macOS 51, *)\n  }}
+        // expected-note@-1 {{add '@available' attribute to enclosing instance method}} {{3-3=@available(macOS 51, *)\n  }}
     functionAvailableOn51()
         // expected-error@-1 {{'functionAvailableOn51()' is only available in macOS 51 or newer}}
         // expected-note@-2 {{add 'if #available' version check}} {{5-28=if #available(macOS 51, *) {\n        functionAvailableOn51()\n    } else {\n        // Fallback on earlier versions\n    }}}
   }
 
   func fixitForReferenceNestedInMethod() {
-          // expected-note@-1 3{{add @available attribute to enclosing instance method}} {{3-3=@available(macOS 51, *)\n  }}
+          // expected-note@-1 3{{add '@available' attribute to enclosing instance method}} {{3-3=@available(macOS 51, *)\n  }}
     func inner() {
       functionAvailableOn51()
           // expected-error@-1 {{'functionAvailableOn51()' is only available in macOS 51 or newer}}
@@ -1528,7 +1535,7 @@ class ClassForFixit {
   }
 
   var fixitForReferenceInPropertyAccessor: Int {
-        // expected-note@-1 {{add @available attribute to enclosing property}} {{3-3=@available(macOS 51, *)\n  }}
+        // expected-note@-1 {{add '@available' attribute to enclosing property}} {{3-3=@available(macOS 51, *)\n  }}
     get {
       functionAvailableOn51()
         // expected-error@-1 {{'functionAvailableOn51()' is only available in macOS 51 or newer}}
@@ -1552,13 +1559,13 @@ class ClassForFixit {
 
   static var fixitForReferenceInStaticPropertyType: ClassAvailableOn51? = nil
       // expected-error@-1 {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
-      // expected-note@-2 {{add @available attribute to enclosing static property}} {{3-3=@available(macOS 51, *)\n  }}
+      // expected-note@-2 {{add '@available' attribute to enclosing static property}} {{3-3=@available(macOS 51, *)\n  }}
 
   var fixitForReferenceInPropertyTypeMultiple: ClassAvailableOn51? = nil, other: Int = 7
       // expected-error@-1 {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
 
   func fixitForRefInGuardOfIf() {
-        // expected-note@-1 {{add @available attribute to enclosing instance method}} {{3-3=@available(macOS 51, *)\n  }}
+        // expected-note@-1 {{add '@available' attribute to enclosing instance method}} {{3-3=@available(macOS 51, *)\n  }}
     if (globalFuncAvailableOn51() > 1066) {
       let _ = 5
       let _ = 6
@@ -1569,9 +1576,9 @@ class ClassForFixit {
 }
 
 extension ClassToExtend {
-        // expected-note@-1 {{add @available attribute to enclosing extension}}
+        // expected-note@-1 {{add '@available' attribute to enclosing extension}}
   func fixitForReferenceInExtensionMethod() {
-        // expected-note@-1 {{add @available attribute to enclosing instance method}} {{3-3=@available(macOS 51, *)\n  }}
+        // expected-note@-1 {{add '@available' attribute to enclosing instance method}} {{3-3=@available(macOS 51, *)\n  }}
     functionAvailableOn51()
         // expected-error@-1 {{'functionAvailableOn51()' is only available in macOS 51 or newer}}
         // expected-note@-2 {{add 'if #available' version check}} {{5-28=if #available(macOS 51, *) {\n        functionAvailableOn51()\n    } else {\n        // Fallback on earlier versions\n    }}}
@@ -1579,7 +1586,7 @@ extension ClassToExtend {
 }
 
 enum EnumForFixit {
-      // expected-note@-1 2{{add @available attribute to enclosing enum}} {{1-1=@available(macOS 51, *)\n}}
+      // expected-note@-1 2{{add '@available' attribute to enclosing enum}} {{1-1=@available(macOS 51, *)\n}}
   case CaseWithPotentiallyUnavailablePayload(p: ClassAvailableOn51)
       // expected-error@-1 {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
 
@@ -1599,7 +1606,7 @@ class X {
 }
 
 func testForFixitWithNestedMemberRefExpr() {
-    // expected-note@-1 2{{add @available attribute to enclosing global function}} {{1-1=@available(macOS 52, *)\n}}
+    // expected-note@-1 2{{add '@available' attribute to enclosing global function}} {{1-1=@available(macOS 52, *)\n}}
   let x = X()
 
   x.y.z = globalFuncAvailableOn52()
@@ -1617,13 +1624,13 @@ func testForFixitWithNestedMemberRefExpr() {
 // Protocol Conformances
 
 protocol ProtocolWithRequirementMentioningPotentiallyUnavailable {
-      // expected-note@-1 2{{add @available attribute to enclosing protocol}}
+      // expected-note@-1 2{{add '@available' attribute to enclosing protocol}}
   func hasPotentiallyUnavailableParameter(_ p: ClassAvailableOn51) // expected-error * {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
-      // expected-note@-1 * {{add @available attribute to enclosing instance method}}
+      // expected-note@-1 * {{add '@available' attribute to enclosing instance method}}
       
 
   func hasPotentiallyUnavailableReturn() -> ClassAvailableOn51 // expected-error * {{'ClassAvailableOn51' is only available in macOS 51 or newer}}
-      // expected-note@-1 * {{add @available attribute to enclosing instance method}}
+      // expected-note@-1 * {{add '@available' attribute to enclosing instance method}}
 
   @available(OSX 51, *)
   func hasPotentiallyUnavailableWithAnnotation(_ p: ClassAvailableOn51) -> ClassAvailableOn51
@@ -1768,13 +1775,13 @@ class ConformsWithPotentiallyUnavailableFunction : HasPotentiallyUnavailableMeth
 }
 
 func usePotentiallyUnavailableProtocolMethod(_ h: HasPotentiallyUnavailableMethodF) {
-      // expected-note@-1 {{add @available attribute to enclosing global function}}
+      // expected-note@-1 {{add '@available' attribute to enclosing global function}}
   h.f("Foo") // expected-error {{'f' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
 }
 
 func usePotentiallyUnavailableProtocolMethod<H : HasPotentiallyUnavailableMethodF> (_ h: H) {
-      // expected-note@-1 {{add @available attribute to enclosing global function}}
+      // expected-note@-1 {{add '@available' attribute to enclosing global function}}
   h.f("Foo") // expected-error {{'f' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
 }
@@ -1807,7 +1814,7 @@ func funcWithShortFormAvailableOn51() {
 
 @available(iOS 14.0, *)
 func funcWithShortFormAvailableOniOS14() {
-  // expected-note@-1 {{add @available attribute to enclosing global function}}
+  // expected-note@-1 {{add '@available' attribute to enclosing global function}}
   let _ = ClassWithShortFormAvailableOn51() // expected-error {{'ClassWithShortFormAvailableOn51' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
 }
@@ -1843,7 +1850,7 @@ func funcWithWeirdShortFormAvailableOn51() {
 }
 
 func useShortFormAvailable() {
-  // expected-note@-1 5{{add @available attribute to enclosing global function}}
+  // expected-note@-1 5{{add '@available' attribute to enclosing global function}}
 
   funcWithShortFormAvailableOn10_9()
 
@@ -1920,26 +1927,26 @@ class StoredPropertiesWithAvailabilityInClosures {
 
 struct PropertyObservers {
   var hasPotentiallyUnavailableObservers: Int {
-    @available(macOS 51, *) // expected-error {{willSet observer for property cannot be marked potentially unavailable with '@available'}}
+    @available(macOS 51, *) // expected-error {{willSet observer cannot be marked potentially unavailable with '@available'}}
     willSet { }
 
-    @available(macOS 51, *) // expected-error {{didSet observer for property cannot be marked potentially unavailable with '@available'}}
+    @available(macOS 51, *) // expected-error {{didSet observer cannot be marked potentially unavailable with '@available'}}
     didSet { }
   }
 
   var hasObsoletedObservers: Int {
-    @available(macOS, obsoleted: 10.9) // expected-error {{willSet observer for property cannot be marked unavailable with '@available'}}
+    @available(macOS, obsoleted: 10.9) // expected-error {{willSet observer cannot be marked unavailable with '@available'}}
     willSet { }
 
-    @available(macOS, obsoleted: 10.9) // expected-error {{didSet observer for property cannot be marked unavailable with '@available'}}
+    @available(macOS, obsoleted: 10.9) // expected-error {{didSet observer cannot be marked unavailable with '@available'}}
     didSet { }
   }
 
   var hasSPIAvailableObservers: Int {
-    @_spi_available(macOS, introduced: 10.9) // expected-error {{willSet observer for property cannot be marked unavailable with '@available'}}
+    @_spi_available(macOS, introduced: 10.9) // expected-error {{willSet observer cannot be marked unavailable with '@available'}}
     willSet { }
 
-    @_spi_available(macOS, introduced: 10.9) // expected-error {{didSet observer for property cannot be marked unavailable with '@available'}}
+    @_spi_available(macOS, introduced: 10.9) // expected-error {{didSet observer cannot be marked unavailable with '@available'}}
     didSet { }
   }
 
diff --git a/test/Availability/availability_versions_canonical.swift b/test/Availability/availability_versions_canonical.swift
new file mode 100644
index 0000000000000..822767f583c63
--- /dev/null
+++ b/test/Availability/availability_versions_canonical.swift
@@ -0,0 +1,105 @@
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target x86_64-apple-macosx10.15 -verify-additional-prefix macos-
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target arm64-apple-ios13 -verify-additional-prefix ios-
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target arm64-apple-watchos6 -verify-additional-prefix watchos-
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target arm64-apple-tvos13 -verify-additional-prefix tvos-
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target arm64-apple-xros1 -verify-additional-prefix visionos-
+
+@available(OSX 10.16, *)
+func introducedOnMacOS10_16() { }
+
+@available(OSX 11.0, *)
+func introducedOnMacOS11_0() { }
+
+@available(macOS 16.0, iOS 19.0, watchOS 12.0, tvOS 19.0, visionOS 3.0, *)
+func introducedInVersionsMappingTo26_0() { }
+
+@available(macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0, *)
+func introducedIn26_0() { }
+
+@available(macOS 17.0, iOS 20.0, watchOS 13.0, tvOS 20.0, visionOS 4.0, *)
+// expected-warning@-1 {{'17.0' is not a valid version number for macOS}}
+// expected-warning@-2 {{'20.0' is not a valid version number for iOS}}
+// expected-warning@-3 {{'13.0' is not a valid version number for watchOS}}
+// expected-warning@-4 {{'20.0' is not a valid version number for tvOS}}
+// expected-warning@-5 {{'4.0' is not a valid version number for visionOS}}
+func introducedInVersionsMappingTo27_0() { }
+
+@available(macOS 27.0, iOS 27.0, watchOS 27.0, tvOS 27.0, visionOS 27.0, *)
+func introducedIn27_0() { }
+
+func useUnderPoundAvailable() {
+  // expected-note@-1 * {{add '@available' attribute to enclosing global function}}
+  introducedOnMacOS10_16()
+  // expected-macos-error@-1 {{'introducedOnMacOS10_16()' is only available in macOS 11.0 or newer}}
+  // expected-macos-note@-2 {{add 'if #available' version check}}
+
+  introducedOnMacOS11_0()
+  // expected-macos-error@-1 {{'introducedOnMacOS11_0()' is only available in macOS 11.0 or newer}}
+  // expected-macos-note@-2 {{add 'if #available' version check}}
+
+  introducedInVersionsMappingTo26_0()
+  // expected-macos-error@-1 {{'introducedInVersionsMappingTo26_0()' is only available in macOS 26.0 or newer}}
+  // expected-ios-error@-2 {{'introducedInVersionsMappingTo26_0()' is only available in iOS 26.0 or newer}}
+  // expected-watchos-error@-3 {{'introducedInVersionsMappingTo26_0()' is only available in watchOS 26.0 or newer}}
+  // expected-tvos-error@-4 {{'introducedInVersionsMappingTo26_0()' is only available in tvOS 26.0 or newer}}
+  // expected-visionos-error@-5 {{'introducedInVersionsMappingTo26_0()' is only available in visionOS 26.0 or newer}}
+  // expected-note@-6 {{add 'if #available' version check}}
+
+  introducedIn26_0()
+  // expected-macos-error@-1 {{'introducedIn26_0()' is only available in macOS 26.0 or newer}}
+  // expected-ios-error@-2 {{'introducedIn26_0()' is only available in iOS 26.0 or newer}}
+  // expected-watchos-error@-3 {{'introducedIn26_0()' is only available in watchOS 26.0 or newer}}
+  // expected-tvos-error@-4 {{'introducedIn26_0()' is only available in tvOS 26.0 or newer}}
+  // expected-visionos-error@-5 {{'introducedIn26_0()' is only available in visionOS 26.0 or newer}}
+  // expected-note@-6 {{add 'if #available' version check}}
+
+  introducedInVersionsMappingTo27_0()
+  // expected-macos-error@-1 {{'introducedInVersionsMappingTo27_0()' is only available in macOS 27.0 or newer}}
+  // expected-ios-error@-2 {{'introducedInVersionsMappingTo27_0()' is only available in iOS 27.0 or newer}}
+  // expected-watchos-error@-3 {{'introducedInVersionsMappingTo27_0()' is only available in watchOS 27.0 or newer}}
+  // expected-tvos-error@-4 {{'introducedInVersionsMappingTo27_0()' is only available in tvOS 27.0 or newer}}
+  // expected-visionos-error@-5 {{'introducedInVersionsMappingTo27_0()' is only available in visionOS 27.0 or newer}}
+  // expected-note@-6 {{add 'if #available' version check}}
+
+  introducedIn27_0()
+  // expected-macos-error@-1 {{'introducedIn27_0()' is only available in macOS 27.0 or newer}}
+  // expected-ios-error@-2 {{'introducedIn27_0()' is only available in iOS 27.0 or newer}}
+  // expected-watchos-error@-3 {{'introducedIn27_0()' is only available in watchOS 27.0 or newer}}
+  // expected-tvos-error@-4 {{'introducedIn27_0()' is only available in tvOS 27.0 or newer}}
+  // expected-visionos-error@-5 {{'introducedIn27_0()' is only available in visionOS 27.0 or newer}}
+  // expected-note@-6 {{add 'if #available' version check}}
+
+  if #available(OSX 10.16, *) {
+    introducedOnMacOS10_16()
+    introducedOnMacOS11_0()
+  }
+
+  if #available(macOS 16.0, iOS 19.0, watchOS 12.0, tvOS 19.0, visionOS 3.0, *) {
+    introducedInVersionsMappingTo26_0()
+    introducedIn26_0()
+    introducedInVersionsMappingTo27_0()
+    // expected-macos-error@-1 {{'introducedInVersionsMappingTo27_0()' is only available in macOS 27.0 or newer}}
+    // expected-ios-error@-2 {{'introducedInVersionsMappingTo27_0()' is only available in iOS 27.0 or newer}}
+    // expected-watchos-error@-3 {{'introducedInVersionsMappingTo27_0()' is only available in watchOS 27.0 or newer}}
+    // expected-tvos-error@-4 {{'introducedInVersionsMappingTo27_0()' is only available in tvOS 27.0 or newer}}
+    // expected-visionos-error@-5 {{'introducedInVersionsMappingTo27_0()' is only available in visionOS 27.0 or newer}}
+    // expected-note@-6 {{add 'if #available' version check}}
+    introducedIn27_0()
+    // expected-macos-error@-1 {{'introducedIn27_0()' is only available in macOS 27.0 or newer}}
+    // expected-ios-error@-2 {{'introducedIn27_0()' is only available in iOS 27.0 or newer}}
+    // expected-watchos-error@-3 {{'introducedIn27_0()' is only available in watchOS 27.0 or newer}}
+    // expected-tvos-error@-4 {{'introducedIn27_0()' is only available in tvOS 27.0 or newer}}
+    // expected-visionos-error@-5 {{'introducedIn27_0()' is only available in visionOS 27.0 or newer}}
+    // expected-note@-6 {{add 'if #available' version check}}
+  }
+
+  if #available(macOS 17.0, iOS 20.0, watchOS 13.0, tvOS 20.0, visionOS 4.0, *) {
+    // expected-warning@-1 {{'17.0' is not a valid version number for macOS}}
+    // expected-warning@-2 {{'20.0' is not a valid version number for iOS}}
+    // expected-warning@-3 {{'13.0' is not a valid version number for watchOS}}
+    // expected-warning@-4 {{'20.0' is not a valid version number for tvOS}}
+    // expected-warning@-5 {{'4.0' is not a valid version number for visionOS}}
+    introducedInVersionsMappingTo27_0()
+    introducedIn27_0()
+  }
+}
diff --git a/test/Sema/availability_versions_multi.swift b/test/Availability/availability_versions_multi.swift
similarity index 94%
rename from test/Sema/availability_versions_multi.swift
rename to test/Availability/availability_versions_multi.swift
index 8ff07c358f3e5..8ec6b7a986352 100644
--- a/test/Sema/availability_versions_multi.swift
+++ b/test/Availability/availability_versions_multi.swift
@@ -18,10 +18,10 @@ var globalAvailableOn99_52: Int = 11
 let ignored1: Int = globalAvailableOn10_9
 
 let ignored2: Int = globalAvailableOn99_51 // expected-error {{'globalAvailableOn99_51' is only available in macOS 99.51 or newer}}
-    // expected-note@-1 {{add @available attribute to enclosing let}}
+    // expected-note@-1 {{add '@available' attribute to enclosing let}}
 
 let ignored3: Int = globalAvailableOn99_52 // expected-error {{'globalAvailableOn99_52' is only available in macOS 99.52 or newer}}
-    // expected-note@-1 {{add @available attribute to enclosing let}}
+    // expected-note@-1 {{add '@available' attribute to enclosing let}}
 
 @available(OSX, introduced: 99.51)
 func useFromOtherOn99_51() {
diff --git a/test/Sema/availability_versions_objc_api.swift b/test/Availability/availability_versions_objc_api.swift
similarity index 93%
rename from test/Sema/availability_versions_objc_api.swift
rename to test/Availability/availability_versions_objc_api.swift
index e3818dd077872..8870e570f5e6a 100644
--- a/test/Sema/availability_versions_objc_api.swift
+++ b/test/Availability/availability_versions_objc_api.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift %clang-importer-sdk -I %S/Inputs/custom-modules
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated %clang-importer-sdk -I %S/Inputs/custom-modules
 // RUN: not %target-swift-frontend -typecheck %clang-importer-sdk -I %S/Inputs/custom-modules %s 2>&1 | %FileCheck %s
 
 // REQUIRES: OS=macosx
@@ -8,7 +8,7 @@ import Foundation
 
 // Tests for uses of version-based potential unavailability imported from ObjC APIs.
 func callUnavailableObjC() {
-      // expected-note@-1 5{{add @available attribute to enclosing global function}}
+      // expected-note@-1 5{{add '@available' attribute to enclosing global function}}
   _ = NSAvailableOn51() // expected-error {{'NSAvailableOn51' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
   
@@ -37,11 +37,11 @@ func callUnavailableObjC() {
 // Declarations with Objective-C-originated potentially unavailable APIs
 
 func functionWithObjCParam(o: NSAvailableOn51) { // expected-error {{'NSAvailableOn51' is only available in macOS 51 or newer}}
-    // expected-note@-1 {{add @available attribute to enclosing global function}}
+    // expected-note@-1 {{add '@available' attribute to enclosing global function}}
 }
 
 class ClassExtendingUnvailableClass : NSAvailableOn51 { // expected-error {{'NSAvailableOn51' is only available in macOS 51 or newer}}
-    // expected-note@-1 {{add @available attribute to enclosing class}}
+    // expected-note@-1 {{add '@available' attribute to enclosing class}}
 }
 
 // We allow classes to conform to potentially unavailable protocols
@@ -70,7 +70,7 @@ let _: NSEnumWithUnavailableElement = .third // expected-error {{'third' is only
 // Differing availability on getters and setters imported from ObjC.
 
 func gettersAndSettersFromObjC(o: NSAvailableOn10_9) {
-      // expected-note@-1 6{{add @available attribute to enclosing global function}}
+      // expected-note@-1 6{{add '@available' attribute to enclosing global function}}
   let _: Int = o.propertyOn51WithSetterOn52After  // expected-error {{'propertyOn51WithSetterOn52After' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
 
@@ -98,7 +98,7 @@ func gettersAndSettersFromObjC(o: NSAvailableOn10_9) {
 // Globals from Objective-C
 
 func useGlobalsFromObjectiveC() {
-      // expected-note@-1 3{{add @available attribute to enclosing global function}}
+      // expected-note@-1 3{{add '@available' attribute to enclosing global function}}
   _ = globalStringAvailableOn51 // expected-error {{'globalStringAvailableOn51' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
 
@@ -166,7 +166,7 @@ class UserClass : UnannotatedFrameworkProtocol {
 }
 
 func callViaUnannotatedFrameworkProtocol(p: UnannotatedFrameworkProtocol) {
-      // expected-note@-1 {{add @available attribute to enclosing global function}}
+      // expected-note@-1 {{add '@available' attribute to enclosing global function}}
   let _ = p.returnSomething() // expected-error {{'returnSomething()' is only available in macOS 51 or newer}}
       // expected-note@-1 {{add 'if #available' version check}}
 }
diff --git a/test/Sema/availability_versions_playgrounds.swift b/test/Availability/availability_versions_playgrounds.swift
similarity index 100%
rename from test/Sema/availability_versions_playgrounds.swift
rename to test/Availability/availability_versions_playgrounds.swift
diff --git a/test/Sema/availability_versions_unsupported.swift b/test/Availability/availability_versions_unsupported.swift
similarity index 100%
rename from test/Sema/availability_versions_unsupported.swift
rename to test/Availability/availability_versions_unsupported.swift
diff --git a/test/Availability/availability_with_overloading.swift b/test/Availability/availability_with_overloading.swift
new file mode 100644
index 0000000000000..59e54eaa50d25
--- /dev/null
+++ b/test/Availability/availability_with_overloading.swift
@@ -0,0 +1,68 @@
+// RUN: %target-swift-frontend -emit-sil -verify %s | %FileCheck %s
+
+// REQUIRES: OS=macosx
+
+protocol View {}
+
+extension View {
+  @_disfavoredOverload
+  func frame(width: Double?, height: Double? = nil) {
+  }
+}
+
+@available(macOS 999, *)
+extension View {
+  func frame(width: Double?) {
+  }
+}
+
+// CHECK-LABEL: sil {{.*}} @$s29availability_with_overloading30test_disfavored_vs_unavailableyyAA4View_pF :
+func test_disfavored_vs_unavailable(_ view: View) {
+  view.frame(width: 100) // Ok
+  // CHECK: function_ref @$s29availability_with_overloading4ViewPAAE5frame5width6heightySdSg_AGtF :
+}
+
+struct S {
+  func foo<T: StringProtocol>(_: T) {}
+  func bar(_: Int, _: Int = 0) {}
+}
+
+@available(macOS 999, *)
+extension S {
+  func foo(_: String) {}
+  func bar(_: Int) {}
+}
+
+// CHECK-LABEL: sil {{.*}} @$s29availability_with_overloading27test_generic_vs_unavailableyyAA1SVF :
+func test_generic_vs_unavailable(_ s: S) {
+  s.foo("") // Ok (picks available generic overload)
+  // CHECK: function_ref @$s29availability_with_overloading1SV3fooyyxSyRzlF :
+  s.bar(42) // Ok (picks overload with defaulted argument)
+  // CHECK: function_ref @$s29availability_with_overloading1SV3baryySi_SitF :
+}
+
+extension S {
+  @available(macOS, obsoleted: 999)
+  func baz(_: Int) {}
+
+  @available(macOS, introduced: 999)
+  func baz(_: Int, _: Int = 0) {}
+}
+
+// CHECK-LABEL: sil {{.*}} @$s29availability_with_overloading28test_introduced_vs_obsoletedyyAA1SVF :
+func test_introduced_vs_obsoleted(_ s: S) {
+  // CHECK: function_ref @$s29availability_with_overloading1SV3bazyySiF :
+  s.baz(42)
+  // CHECK: function_ref @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF :
+  if #available(macOS 999, *) {
+    // CHECK: function_ref @$s29availability_with_overloading1SV3bazyySi_SitF :
+    s.baz(42)
+  }
+}
+
+// CHECK-LABEL: sil {{.*}} @$s29availability_with_overloading29test_introduced_vs_obsoleted2yyAA1SVF :
+@available(macOS 999, *)
+func test_introduced_vs_obsoleted2(_ s: S) {
+  // CHECK: function_ref @$s29availability_with_overloading1SV3bazyySi_SitF :
+  s.baz(42)
+}
diff --git a/test/Sema/conformance_availability.swift b/test/Availability/conformance_availability.swift
similarity index 87%
rename from test/Sema/conformance_availability.swift
rename to test/Availability/conformance_availability.swift
index fe52ca26a773e..9328a5f0865bb 100644
--- a/test/Sema/conformance_availability.swift
+++ b/test/Availability/conformance_availability.swift
@@ -70,7 +70,7 @@ public struct HasUnavailableConformance3 {}
 
 @available(swift 12)
 extension HasUnavailableConformance3 : Horse {}
-// expected-note@-1 12{{conformance of 'HasUnavailableConformance3' to 'Horse' was introduced in Swift 12}}
+// expected-note@-1 6{{conformance of 'HasUnavailableConformance3' to 'Horse' was introduced in Swift 12}}
 
 func passUnavailableConformance3(x: HasUnavailableConformance3) {
   takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
@@ -83,12 +83,12 @@ func passUnavailableConformance3(x: HasUnavailableConformance3) {
 
 @available(swift 12)
 func passUnavailableConformance3a(x: HasUnavailableConformance3) {
-  takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  takesHorseExistential(x) // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  x.giddyUp() // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  _ = x.isGalloping // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  _ = x[keyPath: \.isGalloping] // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  _ = UsesHorse<HasUnavailableConformance3>.self // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
+  takesHorse(x)
+  takesHorseExistential(x)
+  x.giddyUp()
+  _ = x.isGalloping
+  _ = x[keyPath: \.isGalloping]
+  _ = UsesHorse<HasUnavailableConformance3>.self
 }
 
 // Platform obsoleted
@@ -96,7 +96,7 @@ public struct HasUnavailableConformance4 {}
 
 @available(macOS, obsoleted: 10.1)
 extension HasUnavailableConformance4 : Horse {}
-// expected-note@-1 12{{conformance of 'HasUnavailableConformance4' to 'Horse' was obsoleted in macOS 10.1}}
+// expected-note@-1 6{{conformance of 'HasUnavailableConformance4' to 'Horse' was obsoleted in macOS 10.1}}
 
 func passUnavailableConformance4(x: HasUnavailableConformance4) {
   takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
@@ -109,12 +109,12 @@ func passUnavailableConformance4(x: HasUnavailableConformance4) {
 
 @available(macOS, obsoleted: 10.1)
 func passUnavailableConformance4a(x: HasUnavailableConformance4) {
-  takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
-  takesHorseExistential(x) // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
-  x.giddyUp() // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
-  _ = x.isGalloping // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable}}
-  _ = x[keyPath: \.isGalloping] // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable}}
-  _ = UsesHorse<HasUnavailableConformance4>.self // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
+  takesHorse(x)
+  takesHorseExistential(x)
+  x.giddyUp()
+  _ = x.isGalloping
+  _ = x[keyPath: \.isGalloping]
+  _ = UsesHorse<HasUnavailableConformance4>.self
 }
 
 // Swift obsoleted
@@ -122,7 +122,7 @@ public struct HasUnavailableConformance5 {}
 
 @available(swift, obsoleted: 4)
 extension HasUnavailableConformance5 : Horse {}
-// expected-note@-1 12{{conformance of 'HasUnavailableConformance5' to 'Horse' was obsoleted in Swift 4}}
+// expected-note@-1 6{{conformance of 'HasUnavailableConformance5' to 'Horse' was obsoleted in Swift 4}}
 
 func passUnavailableConformance5(x: HasUnavailableConformance5) {
   takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
@@ -135,12 +135,12 @@ func passUnavailableConformance5(x: HasUnavailableConformance5) {
 
 @available(swift, obsoleted: 4)
 func passUnavailableConformance5a(x: HasUnavailableConformance5) {
-  takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  takesHorseExistential(x) // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  x.giddyUp() // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  _ = x.isGalloping // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  _ = x[keyPath: \.isGalloping] // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  _ = UsesHorse<HasUnavailableConformance5>.self // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
+  takesHorse(x)
+  takesHorseExistential(x)
+  x.giddyUp()
+  _ = x.isGalloping
+  _ = x[keyPath: \.isGalloping]
+  _ = UsesHorse<HasUnavailableConformance5>.self
 }
 
 // Unavailable with message
@@ -249,7 +249,7 @@ extension HasAvailableConformance1 : Horse {}
 // See the other test case in test/Sema/conformance_availability_warn.swift for
 // the same example for -swift-version 5.
 
-func passAvailableConformance1(x: HasAvailableConformance1) { // expected-note 6{{add @available attribute to enclosing global function}}
+func passAvailableConformance1(x: HasAvailableConformance1) { // expected-note 6{{add '@available' attribute to enclosing global function}}
   takesHorse(x) // expected-error {{conformance of 'HasAvailableConformance1' to 'Horse' is only available in macOS 100 or newer}}
   // expected-note@-1 {{add 'if #available' version check}}
 
@@ -310,7 +310,7 @@ struct AssocConformanceDeprecated : Rider {
 struct AssocConformanceAvailable1 : Rider {
 // expected-error@-1 {{conformance of 'HasAvailableConformance1' to 'Horse' is only available in macOS 100 or newer}}
 // expected-note@-2 {{in associated type 'Self.H' (inferred as 'HasAvailableConformance1')}}
-// expected-note@-3 {{add @available attribute to enclosing struct}}
+// expected-note@-3 {{add '@available' attribute to enclosing struct}}
   typealias H = HasAvailableConformance1
 }
 
@@ -324,7 +324,7 @@ struct AssocConformanceAvailable3 {}
 extension AssocConformanceAvailable3 : Rider {
 // expected-error@-1 {{conformance of 'HasAvailableConformance1' to 'Horse' is only available in macOS 100 or newer}}
 // expected-note@-2 {{in associated type 'Self.H' (inferred as 'HasAvailableConformance1')}}
-// expected-note@-3 {{add @available attribute to enclosing extension}}
+// expected-note@-3 {{add '@available' attribute to enclosing extension}}
   typealias H = HasAvailableConformance1
 }
 
@@ -348,14 +348,14 @@ struct ConformsToSaddle2 : Saddle {
 
 struct ConformsToSaddle3 : Saddle {
   // expected-error@-1 {{conformance of 'HasAvailableConformance3' to 'Horse' is only available in macOS 200 or newer}}
-  // expected-note@-2 {{add @available attribute to enclosing struct}}
+  // expected-note@-2 {{add '@available' attribute to enclosing struct}}
   // expected-note@-3 {{in associated type 'Self.H' (inferred as 'HasAvailableConformance3'}}
   typealias H = HasAvailableConformance3
 }
 
 struct ConformsToSaddle4 : Saddle {
   // expected-error@-1 {{conformance of 'HasAvailableConformance3' to 'Horse' is only available in macOS 200 or newer}}
-  // expected-note@-2 {{add @available attribute to enclosing struct}}
+  // expected-note@-2 {{add '@available' attribute to enclosing struct}}
   // expected-note@-3 {{in associated type 'Self.H' (inferred as 'HasAvailableConformance3'}}
   @available(macOS 200, *)
   typealias H = HasAvailableConformance3
@@ -374,14 +374,14 @@ struct ConformsToBarn2 : Barn {
 
 struct ConformsToBarn3 : Barn {
   // expected-error@-1 {{conformance of 'HasAvailableConformance3' to 'Horse' is only available in macOS 200 or newer}}
-  // expected-note@-2 {{add @available attribute to enclosing struct}}
+  // expected-note@-2 {{add '@available' attribute to enclosing struct}}
   // expected-note@-3 {{in associated type 'Self.H' (inferred as 'HasAvailableConformance3'}}
   typealias H = HasAvailableConformance3
 }
 
 struct ConformsToBarn4 : Barn {
   // expected-error@-1 {{conformance of 'HasAvailableConformance3' to 'Horse' is only available in macOS 200 or newer}}
-  // expected-note@-2 {{add @available attribute to enclosing struct}}
+  // expected-note@-2 {{add '@available' attribute to enclosing struct}}
   // expected-note@-3 {{in associated type 'Self.H' (inferred as 'HasAvailableConformance3'}}
   @available(macOS 200, *)
   typealias H = HasAvailableConformance3
@@ -443,7 +443,7 @@ struct UnavailableHashable {
 extension UnavailableHashable : Hashable {}
 
 func usesUnavailableHashable(_ c: UnavailableHashable) {
-  // expected-note@-1 2 {{add @available attribute to enclosing global function}}
+  // expected-note@-1 2 {{add '@available' attribute to enclosing global function}}
   _ = Set([c])
   // expected-error@-1 2 {{conformance of 'UnavailableHashable' to 'Hashable' is only available in macOS 100 or newer}}
   // expected-note@-2 2 {{add 'if #available' version check}}
diff --git a/test/Sema/conformance_availability_disambiguate.swift b/test/Availability/conformance_availability_disambiguate.swift
similarity index 100%
rename from test/Sema/conformance_availability_disambiguate.swift
rename to test/Availability/conformance_availability_disambiguate.swift
diff --git a/test/Sema/conformance_availability_overlapping.swift b/test/Availability/conformance_availability_overlapping.swift
similarity index 92%
rename from test/Sema/conformance_availability_overlapping.swift
rename to test/Availability/conformance_availability_overlapping.swift
index 28b09d9155a84..6fba2647dc44a 100644
--- a/test/Sema/conformance_availability_overlapping.swift
+++ b/test/Availability/conformance_availability_overlapping.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module %S/Inputs/conformance_availability_overlapping_other.swift -emit-module-path %t/conformance_availability_overlapping_other.swiftmodule
-// RUN: %target-typecheck-verify-swift -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t
 
 // REQUIRES: OS=macosx
 
diff --git a/test/Sema/conformance_availability_warn.swift b/test/Availability/conformance_availability_warn.swift
similarity index 98%
rename from test/Sema/conformance_availability_warn.swift
rename to test/Availability/conformance_availability_warn.swift
index b7d2c4473c697..9faadb0eb1edb 100644
--- a/test/Sema/conformance_availability_warn.swift
+++ b/test/Availability/conformance_availability_warn.swift
@@ -24,7 +24,7 @@ extension HasAvailableConformance1 : Horse {}
 // See the other test case in test/Sema/conformance_availability.swift for the
 // same example but with -swift-version 6.
 
-func passAvailableConformance1(x: HasAvailableConformance1) { // expected-note 6{{add @available attribute to enclosing global function}}
+func passAvailableConformance1(x: HasAvailableConformance1) { // expected-note 6{{add '@available' attribute to enclosing global function}}
   takesHorse(x) // expected-warning {{conformance of 'HasAvailableConformance1' to 'Horse' is only available in macOS 100 or newer; this is an error in the Swift 6 language mode}}
   // expected-note@-1 {{add 'if #available' version check}}
 
diff --git a/test/Sema/generalized_accessors_availability.swift b/test/Availability/generalized_accessors_availability.swift
similarity index 100%
rename from test/Sema/generalized_accessors_availability.swift
rename to test/Availability/generalized_accessors_availability.swift
diff --git a/test/Availability/inline_array_availability.swift b/test/Availability/inline_array_availability.swift
new file mode 100644
index 0000000000000..aaf809fb97c6c
--- /dev/null
+++ b/test/Availability/inline_array_availability.swift
@@ -0,0 +1,17 @@
+// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx15.0
+
+// REQUIRES: OS=macosx
+
+func foo(x: InlineArray<3, Int>) {}
+// expected-error@-1 {{'InlineArray' is only available in}}
+// expected-note@-2 {{add '@available' attribute to enclosing global function}}
+
+func bar(x: [3 of Int]) {}
+// expected-error@-1 {{'InlineArray' is only available in}}
+// expected-note@-2 {{add '@available' attribute to enclosing global function}}
+
+@available(SwiftStdlib 9999, *)
+func baz(x: InlineArray<3, Int>) {}
+
+@available(SwiftStdlib 9999, *)
+func qux(x: [3 of Int]) {}
diff --git a/test/Constraints/operator_availability.swift b/test/Availability/operator_availability.swift
similarity index 77%
rename from test/Constraints/operator_availability.swift
rename to test/Availability/operator_availability.swift
index 414ae95511917..67ae640f28d11 100644
--- a/test/Constraints/operator_availability.swift
+++ b/test/Availability/operator_availability.swift
@@ -29,3 +29,20 @@ func testAvailability() {
   _ = (1 as Int32) <=< (1 as Int32)   // okay
   _ = (1 as Int32) >=> (1 as Int32)   // expected-error{{'>=>' is unavailable}}
 }
+
+// rdar://problem/152700122
+infix operator ~>
+public func ~><T> (lhs: T, rhs: (T) -> Void) -> T {
+  fatalError()
+}
+
+struct S {
+  @available(macOS 50, *)
+  func f() {}
+}
+
+let s = S() ~> {
+  if #available(macOS 50.0, *) {
+    $0.f()
+  }
+}
diff --git a/test/Sema/pack_conformance_availability.swift b/test/Availability/pack_conformance_availability.swift
similarity index 100%
rename from test/Sema/pack_conformance_availability.swift
rename to test/Availability/pack_conformance_availability.swift
diff --git a/test/Sema/property_wrapper_availability.swift b/test/Availability/property_wrapper_availability.swift
similarity index 79%
rename from test/Sema/property_wrapper_availability.swift
rename to test/Availability/property_wrapper_availability.swift
index daf3ab2771322..d665e3d71b214 100644
--- a/test/Sema/property_wrapper_availability.swift
+++ b/test/Availability/property_wrapper_availability.swift
@@ -23,7 +23,7 @@ struct DeprecatedWrapper<T> {
 
 @available(*, unavailable)
 @propertyWrapper
-struct UnavailableWrapper<T> { // expected-note 8 {{'UnavailableWrapper' has been explicitly marked unavailable here}}
+struct UnavailableWrapper<T> { // expected-note 12 {{'UnavailableWrapper' has been explicitly marked unavailable here}}
   var wrappedValue: T
 }
 
@@ -49,7 +49,7 @@ struct WrappedValueAvailable51<T> {
   }
 }
 
-struct AlwaysAvailableStruct { // expected-note 3 {{add @available attribute to enclosing struct}}
+struct AlwaysAvailableStruct { // expected-note 3 {{add '@available' attribute to enclosing struct}}
   @AlwaysAvailableWrapper var alwaysAvailableExplicit: S
   @AlwaysAvailableWrapper var alwaysAvailableInferred = S()
 
@@ -99,7 +99,7 @@ struct UnavailableStruct {
   @UnavailableWrapper var unavailableInferred = S()
 
   @WrappedValueUnavailableOnMacOS var unavailableWrappedValue: S
-  @WrappedValueAvailable51 var wrappedValueAavailable51: S // expected-error {{'wrappedValue' is only available in macOS 51 or newer}}
+  @WrappedValueAvailable51 var wrappedValueAavailable51: S
 }
 
 @available(macOS, unavailable)
@@ -113,14 +113,14 @@ struct UnavailableOnMacOSStruct {
   @DeprecatedWrapper var deprecatedExplicit: S
   @DeprecatedWrapper var deprecatedInferred = S()
 
-  @UnavailableWrapper var unavailableExplicit: S
-  @UnavailableWrapper var unavailableInferred = S()
+  @UnavailableWrapper var unavailableExplicit: S // expected-error {{'UnavailableWrapper' is unavailable}}
+  @UnavailableWrapper var unavailableInferred = S() // expected-error {{'UnavailableWrapper' is unavailable}}
 
   @WrappedValueUnavailableOnMacOS var unavailableWrappedValue: S
-  @WrappedValueAvailable51 var wrappedValueAavailable51: S // expected-error {{'wrappedValue' is only available in macOS 51 or newer}}
+  @WrappedValueAvailable51 var wrappedValueAavailable51: S
 }
 
-func alwaysAvailableFunc( // expected-note 4 {{add @available attribute to enclosing global function}}
+func alwaysAvailableFunc( // expected-note 4 {{add '@available' attribute to enclosing global function}}
   @AlwaysAvailableWrapper _ alwaysAvailable: S,
   @Available51Wrapper _ available51: S, // expected-error {{'Available51Wrapper' is only available in macOS 51 or newer}}
   @DeprecatedWrapper _ deprecated: S, // expected-warning {{'DeprecatedWrapper' is deprecated}}
@@ -160,14 +160,14 @@ func unavailableFunc(
   @DeprecatedWrapper _ deprecated: S,
   @UnavailableWrapper _ unavailable: S,
   @WrappedValueUnavailableOnMacOS _ unavailableWrappedValue: S,
-  @WrappedValueAvailable51 _ wrappedValueAavailable51: S // expected-error {{'wrappedValue' is only available in macOS 51 or newer}}
+  @WrappedValueAvailable51 _ wrappedValueAavailable51: S
 ) {
   @AlwaysAvailableWrapper var alwaysAvailableLocal = S()
   @Available51Wrapper var available51Local = S()
   @DeprecatedWrapper var deprecatedLocal = S()
   @UnavailableWrapper var unavailableLocal = S()
   @WrappedValueUnavailableOnMacOS var unavailableWrappedValueLocal = S()
-  @WrappedValueAvailable51 var wrappedValueAavailable51 = S() // expected-error {{'wrappedValue' is only available in macOS 51 or newer}}
+  @WrappedValueAvailable51 var wrappedValueAavailable51 = S()
 }
 
 @available(macOS, unavailable)
@@ -175,14 +175,47 @@ func unavailableOnMacOSFunc(
   @AlwaysAvailableWrapper _ alwaysAvailable: S,
   @Available51Wrapper _ available51: S,
   @DeprecatedWrapper _ deprecated: S,
-  @UnavailableWrapper _ unavailable: S,
+  @UnavailableWrapper _ unavailable: S, // expected-error {{'UnavailableWrapper' is unavailable}}
   @WrappedValueUnavailableOnMacOS _ unavailableWrappedValue: S,
-  @WrappedValueAvailable51 _ wrappedValueAavailable51: S // expected-error {{'wrappedValue' is only available in macOS 51 or newer}}
+  @WrappedValueAvailable51 _ wrappedValueAavailable51: S
 ) {
   @AlwaysAvailableWrapper var alwaysAvailableLocal = S()
   @Available51Wrapper var available51Local = S()
   @DeprecatedWrapper var deprecatedLocal = S()
-  @UnavailableWrapper var unavailableLocal = S()
+  @UnavailableWrapper var unavailableLocal = S() // expected-error {{'UnavailableWrapper' is unavailable}}
   @WrappedValueUnavailableOnMacOS var unavailableWrappedValueLocal = S()
-  @WrappedValueAvailable51 var wrappedValueAavailable51 = S() // expected-error {{'wrappedValue' is only available in macOS 51 or newer}}
+  @WrappedValueAvailable51 var wrappedValueAavailable51 = S()
+}
+
+@propertyWrapper
+struct Observable<Value> {
+  private var stored: Value
+
+  init(wrappedValue: Value) {
+    self.stored = wrappedValue
+  }
+
+  var wrappedValue: Value {
+    get { fatalError() }
+    set { fatalError() }
+  }
+
+  static subscript<EnclosingSelf>(
+      _enclosingInstance observed: EnclosingSelf,
+      wrapped wrappedKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Value>,
+      storage storageKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Self>
+    ) -> Value {
+    get { fatalError() }
+    set { fatalError() }
+  }
+}
+
+@available(macOS, unavailable)
+class UnavailableOnMacOSObserved {
+  @Observable var observedProperty = 17
+}
+
+@available(*, unavailable)
+class UniversallyUnavailableObserved {
+  @Observable var observedProperty = 17
 }
diff --git a/test/Constraints/result_builder_availability.swift b/test/Availability/result_builder_availability.swift
similarity index 100%
rename from test/Constraints/result_builder_availability.swift
rename to test/Availability/result_builder_availability.swift
diff --git a/test/Sema/spi-available-context.swift b/test/Availability/spi-available-context.swift
similarity index 100%
rename from test/Sema/spi-available-context.swift
rename to test/Availability/spi-available-context.swift
diff --git a/test/Sema/spi-available-inline.swift b/test/Availability/spi-available-inline.swift
similarity index 100%
rename from test/Sema/spi-available-inline.swift
rename to test/Availability/spi-available-inline.swift
diff --git a/test/Sema/spi-available-local.swift b/test/Availability/spi-available-local.swift
similarity index 100%
rename from test/Sema/spi-available-local.swift
rename to test/Availability/spi-available-local.swift
diff --git a/test/Sema/spi-available-swift-module.swift b/test/Availability/spi-available-swift-module.swift
similarity index 91%
rename from test/Sema/spi-available-swift-module.swift
rename to test/Availability/spi-available-swift-module.swift
index bfb6e8254911b..d13c9a875cb95 100644
--- a/test/Sema/spi-available-swift-module.swift
+++ b/test/Availability/spi-available-swift-module.swift
@@ -3,7 +3,7 @@
 // RUN: split-file %s %t
 
 // RUN: %target-swift-frontend -parse-as-library %t/Foo.swift -emit-module -library-level api -emit-module-path %t/Foo.swiftmodule -module-name Foo
-// RUN: %target-swift-frontend-typecheck -parse-as-library %t/Client.swift -verify -library-level api -I %t
+// RUN: %target-swift-frontend-typecheck -parse-as-library %t/Client.swift -verify -verify-ignore-unrelated -library-level api -I %t
 
 //--- Foo.swift
 
diff --git a/test/Availability/value_generics_availability.swift b/test/Availability/value_generics_availability.swift
new file mode 100644
index 0000000000000..01755a8d4e298
--- /dev/null
+++ b/test/Availability/value_generics_availability.swift
@@ -0,0 +1,14 @@
+// RUN: %target-typecheck-verify-swift
+
+// REQUIRES: OS=macosx
+
+struct A<let N: Int> {} // expected-error {{values in generic types are only available in macOS 26.0.0 or newer}}
+                        // expected-note@-1 {{add '@available' attribute to enclosing generic struct}}
+
+class B<let N: Int> {} // expected-error {{values in generic types are only available in macOS 26.0.0 or newer}}
+                       // expected-note@-1 {{add '@available' attribute to enclosing generic class}}
+
+enum C<let N: Int> {} // expected-error {{values in generic types are only available in macOS 26.0.0 or newer}}
+                      // expected-note@-1 {{add '@available' attribute to enclosing generic enum}}
+
+func something<let N: Int>(_: A<N>) {} // OK, because A can't reference value generics.
diff --git a/test/Backtracing/Crash.swift b/test/Backtracing/Crash.swift
deleted file mode 100644
index b91c19d48b9c6..0000000000000
--- a/test/Backtracing/Crash.swift
+++ /dev/null
@@ -1,177 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: %target-build-swift %s -parse-as-library -Onone -g -o %t/Crash
-// RUN: %target-build-swift %s -parse-as-library -Onone -o %t/CrashNoDebug
-// RUN: %target-build-swift %s -parse-as-library -O -g -o %t/CrashOpt
-// RUN: %target-build-swift %s -parse-as-library -O -o %t/CrashOptNoDebug
-// RUN: %target-codesign %t/Crash
-// RUN: %target-codesign %t/CrashNoDebug
-// RUN: %target-codesign %t/CrashOpt
-// RUN: %target-codesign %t/CrashOptNoDebug
-// RUN: (env SWIFT_BACKTRACE=enable=yes,cache=no %target-run %t/Crash 2>&1 || true) | %FileCheck %s
-// RUN: (env SWIFT_BACKTRACE=preset=friendly,enable=yes,cache=no %target-run %t/Crash 2>&1 || true) | %FileCheck %s --check-prefix FRIENDLY
-// RUN: (env SWIFT_BACKTRACE=enable=yes,cache=no %target-run %t/CrashNoDebug 2>&1 || true) | %FileCheck %s --check-prefix NODEBUG
-// RUN: (env SWIFT_BACKTRACE=enable=yes,cache=no %target-run %t/CrashOpt 2>&1 || true) | %FileCheck %s --check-prefix OPTIMIZED
-// RUN: (env SWIFT_BACKTRACE=enable=yes,cache=no %target-run %t/CrashOptNoDebug 2>&1 || true) | %FileCheck %s --check-prefix OPTNODEBUG
-
-// UNSUPPORTED: use_os_stdlib
-// UNSUPPORTED: back_deployment_runtime
-// UNSUPPORTED: asan
-// REQUIRES: executable_test
-// REQUIRES: backtracing
-// REQUIRES: OS=macosx || OS=linux-gnu
-
-func level1() {
-  level2()
-}
-
-func level2() {
-  level3()
-}
-
-func level3() {
-  level4()
-}
-
-func level4() {
-  level5()
-}
-
-func level5() {
-  print("About to crash")
-  let ptr = UnsafeMutablePointer<Int>(bitPattern: 4)!
-  ptr.pointee = 42
-}
-
-@main
-struct Crash {
-  static func main() {
-    level1()
-  }
-}
-
-// CHECK: *** Program crashed: Bad pointer dereference at 0x{{0+}}4 ***
-
-// CHECK: Thread 0 {{(".*" )?}}crashed:
-
-// CHECK: 0               0x{{[0-9a-f]+}} level5() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:42:15
-// CHECK-NEXT: 1 [ra]          0x{{[0-9a-f]+}} level4() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:36:3
-// CHECK-NEXT: 2 [ra]          0x{{[0-9a-f]+}} level3() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:32:3
-// CHECK-NEXT: 3 [ra]          0x{{[0-9a-f]+}} level2() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:28:3
-// CHECK-NEXT: 4 [ra]          0x{{[0-9a-f]+}} level1() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:24:3
-// CHECK-NEXT: 5 [ra]          0x{{[0-9a-f]+}} static Crash.main() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:48:5
-// CHECK-NEXT: 6 [ra] [system] 0x{{[0-9a-f]+}} static Crash.$main() + {{[0-9]+}} in Crash at {{.*}}/<compiler-generated>
-// CHECK-NEXT: 7 [ra] [system] 0x{{[0-9a-f]+}} main + {{[0-9]+}} in Crash at {{.*}}/Crash.swift
-
-// CHECK: Registers:
-
-// CHECK: Images ({{[0-9]+}} omitted):
-
-// CHECK: {{0x[0-9a-f]+}}–{{0x[0-9a-f]+}}{{ +}}{{([0-9a-f]+|<no build ID>)}}{{ +}}Crash{{ +}}{{.*}}/Crash
-
-// FRIENDLY: *** Program crashed: Bad pointer dereference at 0x{{0+}}4 ***
-
-// FRIENDLY: Thread 0 {{(".*" )?}}crashed:
-
-// FRIENDLY: 0 level5() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:42:15
-
-// FRIENDLY: 40|   print("About to crash")
-// FRIENDLY-NEXT: 41|   let ptr = UnsafeMutablePointer<Int>(bitPattern: 4)!
-// FRIENDLY-NEXT: 42|   ptr.pointee = 42
-// FRIENDLY-NEXT:   |               ^
-// FRIENDLY-NEXT: 43| }
-// FRIENDLY-NEXT: 44|
-
-// FRIENDLY: 1 level4() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:36:3
-
-// FRIENDLY: 34|
-// FRIENDLY-NEXT: 35| func level4() {
-// FRIENDLY-NEXT: 36|   level5()
-// FRIENDLY-NEXT:   |   ^
-// FRIENDLY-NEXT: 37| }
-// FRIENDLY-NEXT: 38|
-
-// FRIENDLY: 2 level3() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:32:3
-
-// FRIENDLY: 30|
-// FRIENDLY-NEXT: 31| func level3() {
-// FRIENDLY-NEXT: 32|   level4()
-// FRIENDLY-NEXT:   |   ^
-// FRIENDLY-NEXT: 33| }
-// FRIENDLY-NEXT: 34|
-
-// FRIENDLY: 3 level2() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:28:3
-
-// FRIENDLY: 26|
-// FRIENDLY-NEXT: 27| func level2() {
-// FRIENDLY-NEXT: 28|   level3()
-// FRIENDLY-NEXT:   |   ^
-// FRIENDLY-NEXT: 29| }
-// FRIENDLY-NEXT: 30|
-
-// FRIENDLY: 4 level1() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:24:3
-
-// FRIENDLY:  22|
-// FRIENDLY-NEXT: 23| func level1() {
-// FRIENDLY-NEXT: 24|   level2()
-// FRIENDLY-NEXT:   |   ^
-// FRIENDLY-NEXT: 25| }
-// FRIENDLY-NEXT: 26|
-
-// FRIENDLY: 5 static Crash.main() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:48:5
-
-// FRIENDLY: 46| struct Crash {
-// FRIENDLY-NEXT: 47|   static func main() {
-// FRIENDLY-NEXT: 48|     level1()
-// FRIENDLY-NEXT:   |     ^
-// FRIENDLY-NEXT: 49|   }
-// FRIENDLY-NEXT: 50| }
-
-// NODEBUG: *** Program crashed: Bad pointer dereference at 0x{{0*}}4 ***
-
-// NODEBUG: Thread 0 {{(".*" )?}}crashed:
-
-// NODEBUG: 0               0x{{[0-9a-f]+}} level5() + {{[0-9]+}} in CrashNoDebug
-// NODEBUG: 1 [ra]          0x{{[0-9a-f]+}} level4() + {{[0-9]+}} in CrashNoDebug
-// NODEBUG: 2 [ra]          0x{{[0-9a-f]+}} level3() + {{[0-9]+}} in CrashNoDebug
-// NODEBUG: 3 [ra]          0x{{[0-9a-f]+}} level2() + {{[0-9]+}} in CrashNoDebug
-// NODEBUG: 4 [ra]          0x{{[0-9a-f]+}} level1() + {{[0-9]+}} in CrashNoDebug
-// NODEBUG: 5 [ra]          0x{{[0-9a-f]+}} static Crash.main() + {{[0-9]+}} in CrashNoDebug
-// NODEBUG: 6 [ra] [system] 0x{{[0-9a-f]+}} static Crash.$main() + {{[0-9]+}} in CrashNoDebug
-// NODEBUG: 7 [ra]          0x{{[0-9a-f]+}} main + {{[0-9]+}} in CrashNoDebug
-
-// NODEBUG: Registers:
-
-// NODEBUG: Images ({{[0-9]+}} omitted):
-
-// NODEBUG: {{0x[0-9a-f]+}}–{{0x[0-9a-f]+}}{{ +}}{{([0-9a-f]+|<no build ID>)}}{{ +}}CrashNoDebug{{ +}}{{.*}}/CrashNoDebug
-
-// OPTIMIZED: *** Program crashed: Bad pointer dereference at 0x{{0+}}4 ***
-
-// OPTIMIZED: Thread 0 {{(".*" )?}}crashed:
-
-// OPTIMIZED: 0 [inlined]          0x{{[0-9a-f]+}} level5() in CrashOpt at {{.*}}/Crash.swift:42:15
-// OPTIMIZED-NEXT: 1 [inlined]          0x{{[0-9a-f]+}} level4() in CrashOpt at {{.*}}/Crash.swift:36:3
-// OPTIMIZED-NEXT: 2 [inlined]          0x{{[0-9a-f]+}} level3() in CrashOpt at {{.*}}/Crash.swift:32:3
-// OPTIMIZED-NEXT: 3 [inlined]          0x{{[0-9a-f]+}} level2() in CrashOpt at {{.*}}/Crash.swift:28:3
-// OPTIMIZED-NEXT: 4 [inlined]          0x{{[0-9a-f]+}} level1() in CrashOpt at {{.*}}/Crash.swift:24:3
-// OPTIMIZED-NEXT: 5 [inlined]          0x{{[0-9a-f]+}} static Crash.main() in CrashOpt at {{.*}}/Crash.swift:48:5
-// OPTIMIZED: {{6|7}} [system]           0x{{[0-9a-f]+}} main + {{[0-9]+}} in CrashOpt at {{.*}}
-
-// OPTIMIZED: Registers:
-
-// OPTIMIZED: Images ({{[0-9]+}} omitted):
-
-// OPTIMIZED: {{0x[0-9a-f]+}}–{{0x[0-9a-f]+}}{{ +}}{{([0-9a-f]+|<no build ID>)}}{{ +}}CrashOpt{{ +}}{{.*}}/CrashOpt
-
-// OPTNODEBUG: *** Program crashed: Bad pointer dereference at 0x{{0*}}4 ***
-
-// OPTNODEBUG: Thread 0 {{(".*" )?}}crashed:
-
-// OPTNODEBUG: 0               0x{{[0-9a-f]+}} main + {{[0-9]+}} in CrashOptNoDebug
-
-// OPTNODEBUG: Registers:
-
-// OPTNODEBUG: Images ({{[0-9]+}} omitted):
-
-// OPTNODEBUG: {{0x[0-9a-f]+}}–{{0x[0-9a-f]+}}{{ +}}{{([0-9a-f]+|<no build ID>)}}{{ +}}CrashOptNoDebug{{ +}}{{.*}}/CrashOptNoDebug
-
diff --git a/test/Backtracing/Crash.test b/test/Backtracing/Crash.test
new file mode 100644
index 0000000000000..56e47d3a99c3d
--- /dev/null
+++ b/test/Backtracing/Crash.test
@@ -0,0 +1,147 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %S/Inputs/Crash.swift -parse-as-library -Onone -g -o %t/Crash
+// RUN: %target-build-swift %S/Inputs/Crash.swift -parse-as-library -Onone -o %t/CrashNoDebug
+// RUN: %target-build-swift %S/Inputs/Crash.swift -parse-as-library -O -g -o %t/CrashOpt
+// RUN: %target-build-swift %S/Inputs/Crash.swift -parse-as-library -O -o %t/CrashOptNoDebug
+// RUN: %target-codesign %t/Crash
+// RUN: %target-codesign %t/CrashNoDebug
+// RUN: %target-codesign %t/CrashOpt
+// RUN: %target-codesign %t/CrashOptNoDebug
+// RUN: (env SWIFT_BACKTRACE=enable=yes,cache=no %target-run %t/Crash 2>&1 || true) | %FileCheck %s
+// RUN: (env SWIFT_BACKTRACE=preset=friendly,enable=yes,cache=no %target-run %t/Crash 2>&1 || true) | %FileCheck %s --check-prefix FRIENDLY
+// RUN: (env SWIFT_BACKTRACE=enable=yes,cache=no %target-run %t/CrashNoDebug 2>&1 || true) | %FileCheck %s --check-prefix NODEBUG
+// RUN: (env SWIFT_BACKTRACE=enable=yes,cache=no %target-run %t/CrashOpt 2>&1 || true) | %FileCheck %s --check-prefix OPTIMIZED
+// RUN: (env SWIFT_BACKTRACE=enable=yes,cache=no %target-run %t/CrashOptNoDebug 2>&1 || true) | %FileCheck %s --check-prefix OPTNODEBUG
+
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: asan
+// REQUIRES: executable_test
+// REQUIRES: backtracing
+// REQUIRES: OS=macosx || OS=linux-gnu
+
+
+// CHECK: *** Program crashed: Bad pointer dereference at 0x{{0+}}4 ***
+
+// CHECK: Thread 0 {{(".*" )?}}crashed:
+
+// CHECK: 0               0x{{[0-9a-f]+}} level5() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:20:15
+// CHECK-NEXT: 1 [ra]          0x{{[0-9a-f]+}} level4() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:14:3
+// CHECK-NEXT: 2 [ra]          0x{{[0-9a-f]+}} level3() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:10:3
+// CHECK-NEXT: 3 [ra]          0x{{[0-9a-f]+}} level2() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:6:3
+// CHECK-NEXT: 4 [ra]          0x{{[0-9a-f]+}} level1() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:2:3
+// CHECK-NEXT: 5 [ra]          0x{{[0-9a-f]+}} static Crash.main() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:26:5
+// CHECK-NEXT: 6 [ra] [system] 0x{{[0-9a-f]+}} static Crash.$main() + {{[0-9]+}} in Crash at {{.*}}/<compiler-generated>
+// CHECK-NEXT: 7 [ra] [system] 0x{{[0-9a-f]+}} main + {{[0-9]+}} in Crash at {{.*}}/Crash.swift
+
+// CHECK: Registers:
+
+// CHECK: Images ({{[0-9]+}} omitted):
+
+// CHECK: {{0x[0-9a-f]+}}–{{0x[0-9a-f]+}}{{ +}}{{([0-9a-f]+|<no build ID>)}}{{ +}}Crash{{ +}}{{.*}}/Crash
+
+// FRIENDLY: *** Program crashed: Bad pointer dereference at 0x{{0+}}4 ***
+
+// FRIENDLY: Thread 0 {{(".*" )?}}crashed:
+
+// FRIENDLY: 0 level5() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:20:15
+
+// FRIENDLY: 18|   print("About to crash")
+// FRIENDLY-NEXT: 19|   let ptr = UnsafeMutablePointer<Int>(bitPattern: 4)!
+// FRIENDLY-NEXT: 20|   ptr.pointee = 42
+// FRIENDLY-NEXT:   |               ^
+// FRIENDLY-NEXT: 21| }
+// FRIENDLY-NEXT: 22|
+
+// FRIENDLY: 1 level4() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:14:3
+
+// FRIENDLY: 12|
+// FRIENDLY-NEXT: 13| func level4() {
+// FRIENDLY-NEXT: 14|   level5()
+// FRIENDLY-NEXT:   |   ^
+// FRIENDLY-NEXT: 15| }
+// FRIENDLY-NEXT: 16|
+
+// FRIENDLY: 2 level3() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:10:3
+
+// FRIENDLY: 8|
+// FRIENDLY-NEXT: 9| func level3() {
+// FRIENDLY-NEXT: 10|   level4()
+// FRIENDLY-NEXT:   |   ^
+// FRIENDLY-NEXT: 11| }
+// FRIENDLY-NEXT: 12|
+
+// FRIENDLY: 3 level2() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:6:3
+
+// FRIENDLY: 4|
+// FRIENDLY-NEXT: 5| func level2() {
+// FRIENDLY-NEXT: 6|   level3()
+// FRIENDLY-NEXT:   |   ^
+// FRIENDLY-NEXT: 7| }
+// FRIENDLY-NEXT: 8|
+
+// FRIENDLY: 4 level1() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:2:3
+
+// FRIENDLY:      1| func level1() {
+// FRIENDLY-NEXT: 2|   level2()
+// FRIENDLY-NEXT:   |   ^
+// FRIENDLY-NEXT: 3| }
+
+// FRIENDLY: 5 static Crash.main() + {{[0-9]+}} in Crash at {{.*}}/Crash.swift:26:5
+
+// FRIENDLY: 24| struct Crash {
+// FRIENDLY-NEXT: 25|   static func main() {
+// FRIENDLY-NEXT: 26|     level1()
+// FRIENDLY-NEXT:   |     ^
+// FRIENDLY-NEXT: 27|   }
+// FRIENDLY-NEXT: 28| }
+
+// NODEBUG: *** Program crashed: Bad pointer dereference at 0x{{0*}}4 ***
+
+// NODEBUG: Thread 0 {{(".*" )?}}crashed:
+
+// NODEBUG: 0               0x{{[0-9a-f]+}} level5() + {{[0-9]+}} in CrashNoDebug
+// NODEBUG: 1 [ra]          0x{{[0-9a-f]+}} level4() + {{[0-9]+}} in CrashNoDebug
+// NODEBUG: 2 [ra]          0x{{[0-9a-f]+}} level3() + {{[0-9]+}} in CrashNoDebug
+// NODEBUG: 3 [ra]          0x{{[0-9a-f]+}} level2() + {{[0-9]+}} in CrashNoDebug
+// NODEBUG: 4 [ra]          0x{{[0-9a-f]+}} level1() + {{[0-9]+}} in CrashNoDebug
+// NODEBUG: 5 [ra]          0x{{[0-9a-f]+}} static Crash.main() + {{[0-9]+}} in CrashNoDebug
+// NODEBUG: 6 [ra] [system] 0x{{[0-9a-f]+}} static Crash.$main() + {{[0-9]+}} in CrashNoDebug
+// NODEBUG: 7 [ra]          0x{{[0-9a-f]+}} main + {{[0-9]+}} in CrashNoDebug
+
+// NODEBUG: Registers:
+
+// NODEBUG: Images ({{[0-9]+}} omitted):
+
+// NODEBUG: {{0x[0-9a-f]+}}–{{0x[0-9a-f]+}}{{ +}}{{([0-9a-f]+|<no build ID>)}}{{ +}}CrashNoDebug{{ +}}{{.*}}/CrashNoDebug
+
+// OPTIMIZED: *** Program crashed: Bad pointer dereference at 0x{{0+}}4 ***
+
+// OPTIMIZED: Thread 0 {{(".*" )?}}crashed:
+
+// OPTIMIZED: 0 [inlined]          0x{{[0-9a-f]+}} level5() in CrashOpt at {{.*}}/Crash.swift:20:15
+// OPTIMIZED-NEXT: 1 [inlined]          0x{{[0-9a-f]+}} level4() in CrashOpt at {{.*}}/Crash.swift:14:3
+// OPTIMIZED-NEXT: 2 [inlined]          0x{{[0-9a-f]+}} level3() in CrashOpt at {{.*}}/Crash.swift:10:3
+// OPTIMIZED-NEXT: 3 [inlined]          0x{{[0-9a-f]+}} level2() in CrashOpt at {{.*}}/Crash.swift:6:3
+// OPTIMIZED-NEXT: 4 [inlined]          0x{{[0-9a-f]+}} level1() in CrashOpt at {{.*}}/Crash.swift:2:3
+// OPTIMIZED-NEXT: 5 [inlined]          0x{{[0-9a-f]+}} static Crash.main() in CrashOpt at {{.*}}/Crash.swift:26:5
+// OPTIMIZED: {{6|7}} [system]           0x{{[0-9a-f]+}} main + {{[0-9]+}} in CrashOpt at {{.*}}
+
+// OPTIMIZED: Registers:
+
+// OPTIMIZED: Images ({{[0-9]+}} omitted):
+
+// OPTIMIZED: {{0x[0-9a-f]+}}–{{0x[0-9a-f]+}}{{ +}}{{([0-9a-f]+|<no build ID>)}}{{ +}}CrashOpt{{ +}}{{.*}}/CrashOpt
+
+// OPTNODEBUG: *** Program crashed: Bad pointer dereference at 0x{{0*}}4 ***
+
+// OPTNODEBUG: Thread 0 {{(".*" )?}}crashed:
+
+// OPTNODEBUG: 0               0x{{[0-9a-f]+}} main + {{[0-9]+}} in CrashOptNoDebug
+
+// OPTNODEBUG: Registers:
+
+// OPTNODEBUG: Images ({{[0-9]+}} omitted):
+
+// OPTNODEBUG: {{0x[0-9a-f]+}}–{{0x[0-9a-f]+}}{{ +}}{{([0-9a-f]+|<no build ID>)}}{{ +}}CrashOptNoDebug{{ +}}{{.*}}/CrashOptNoDebug
+
diff --git a/test/Backtracing/Inputs/Crash.swift b/test/Backtracing/Inputs/Crash.swift
new file mode 100644
index 0000000000000..9fec6c3fb0158
--- /dev/null
+++ b/test/Backtracing/Inputs/Crash.swift
@@ -0,0 +1,28 @@
+func level1() {
+  level2()
+}
+
+func level2() {
+  level3()
+}
+
+func level3() {
+  level4()
+}
+
+func level4() {
+  level5()
+}
+
+func level5() {
+  print("About to crash")
+  let ptr = UnsafeMutablePointer<Int>(bitPattern: 4)!
+  ptr.pointee = 42
+}
+
+@main
+struct Crash {
+  static func main() {
+    level1()
+  }
+}
\ No newline at end of file
diff --git a/test/CAS/Inputs/BuildCommandExtractor.py b/test/CAS/Inputs/BuildCommandExtractor.py
index 7140e0193e7c9..487e2e7559704 100755
--- a/test/CAS/Inputs/BuildCommandExtractor.py
+++ b/test/CAS/Inputs/BuildCommandExtractor.py
@@ -31,7 +31,8 @@ def printCmd(cmd):
         cmd = info["bridgingHeader"]["commandLine"][1:]
         printCmd(cmd)
         # print input file name.
-        print(info["chainedBridgingHeaderPath"])
+        if "chainedBridgingHeaderPath" in info:
+            print(info["chainedBridgingHeaderPath"])
     else:
         module_names = deps["modules"][::2]
         module_details = deps["modules"][1::2]
diff --git a/test/CAS/Inputs/SwiftDepsExtractor.py b/test/CAS/Inputs/SwiftDepsExtractor.py
index 3295c4f69fe2b..6d43f0280c39e 100755
--- a/test/CAS/Inputs/SwiftDepsExtractor.py
+++ b/test/CAS/Inputs/SwiftDepsExtractor.py
@@ -10,6 +10,7 @@
 key = sys.argv[3]
 
 mode = 'swift'
+is_bridging_header = False
 
 if module_name.startswith('clang:'):
     mode = 'clang'
@@ -17,6 +18,9 @@
 elif module_name.startswith('swiftPrebuiltExternal:'):
     mode = 'swiftPrebuiltExternal'
     module_name = module_name[22:]
+elif module_name.startswith('bridgingHeader:'):
+    is_bridging_header = True
+    module_name = module_name[15:]
 
 with open(input_json, 'r') as file:
     deps = json.load(file)
@@ -30,5 +34,10 @@
             json.dump(detail[key], sys.stdout, indent=2)
             break
 
+        if is_bridging_header:
+            json.dump(detail['details'][mode]['bridgingHeader']
+                      [key], sys.stdout, indent=2)
+            break
+
         json.dump(detail['details'][mode][key], sys.stdout, indent=2)
         break
diff --git a/test/CAS/access-notes.swift b/test/CAS/access-notes.swift
new file mode 100644
index 0000000000000..868e90929aced
--- /dev/null
+++ b/test/CAS/access-notes.swift
@@ -0,0 +1,41 @@
+// REQUIRES: objc_interop
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/main.swift -o %t/deps.json -swift-version 5 -cache-compile-job -cas-path %t/cas -access-notes-path %t/extra.accessnotes
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps.json > %t/map.json
+// RUN: llvm-cas --cas %t/cas --make-blob --data %t/map.json > %t/map.casid
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json Test > %t/MyApp.cmd
+
+// RUN: %target-swift-frontend \
+// RUN:   -typecheck -cache-compile-job -cas-path %t/cas \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
+// RUN:   %t/main.swift @%t/MyApp.cmd -access-notes-path %t/extra.accessnotes -Raccess-note=all 2>&1 | %FileCheck %s
+
+//--- main.swift
+class Extant {
+  func good(_: Int) {} // expected-remark * {{}} expected-note * {{}}
+  // CHECK-DAG: main.swift:2:{{[0-9]+}}: remark: implicitly added '@objc' to this instance method, as specified by access note for Access notes containing future, unknown syntax
+  // CHECK-DAG: note: add '@objc' explicitly to silence this warning
+
+  func bad(_: Int?) {} // expected-remark * {{}}
+  // CHECK-DAG: main.swift:6:{{[0-9]+}}: remark: ignored access note: instance method cannot be marked '@objc' by an access note because the type of the parameter cannot be represented in Objective-C; did not implicitly add '@objc' to this instance method, even though it was specified by access note for Access notes containing future, unknown syntax
+}
+
+//--- extra.accessnotes
+Reason: Access notes containing future, unknown syntax
+Notes:
+- Name: 'Extant.good(_:)'
+  ObjC: true
+- Name: 'Extant.bad(_:)'
+  ObjC: true
diff --git a/test/CAS/block-list.swift b/test/CAS/block-list.swift
index c14298f8b6be7..88736827be18c 100644
--- a/test/CAS/block-list.swift
+++ b/test/CAS/block-list.swift
@@ -4,7 +4,7 @@
 // RUN: %target-swift-frontend -scan-dependencies -module-name Test -O \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
 // RUN:   -blocklist-file %t/blocklist.yml -blocklist-file %t/empty.yml \
-// RUN:   -scanner-prefix-map %t=/^tmp -I %t/include \
+// RUN:   -scanner-prefix-map-paths %t /^tmp -I %t/include \
 // RUN:   %t/main.swift -o %t/deps.json -cache-compile-job -cas-path %t/cas 
 
 // RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
@@ -38,7 +38,7 @@
 // RUN:   -blocklist-file /^tmp/blocklist.yml -blocklist-file /^tmp/empty.yml \
 // RUN:   -enable-layout-string-value-witnesses -enable-layout-string-value-witnesses-instantiation \
 // RUN:   -enable-experimental-feature LayoutStringValueWitnesses -enable-experimental-feature LayoutStringValueWitnessesInstantiation \
-// RUN:   -cache-replay-prefix-map /^tmp=%t \
+// RUN:   -cache-replay-prefix-map /^tmp %t \
 // RUN:   /^tmp/main.swift @%t/MyApp.cmd 2>&1 | %FileCheck %s --check-prefix CHECK-BLOCKED
 
 // REQUIRES: swift_feature_LayoutStringValueWitnesses
diff --git a/test/CAS/bridging-header-prefix-map.swift b/test/CAS/bridging-header-prefix-map.swift
new file mode 100644
index 0000000000000..fb594e082a08b
--- /dev/null
+++ b/test/CAS/bridging-header-prefix-map.swift
@@ -0,0 +1,99 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+/// Test prefix mapped bridging header path will result in the same cache key.
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/test.swift -o %t/deps-1.json -auto-bridging-header-chaining -cache-compile-job -cas-path %t/cas \
+// RUN:   -scanner-prefix-map-paths %swift_src_root /^src -scanner-prefix-map-paths %t /^tmp \
+// RUN:   -scanner-prefix-map-paths %t/header-1 /^header \
+// RUN:   -scanner-output-dir %t/header-1 -import-objc-header %t/header-1/Bridging.h
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/test.swift -o %t/deps-2.json -auto-bridging-header-chaining -cache-compile-job -cas-path %t/cas \
+// RUN:   -scanner-prefix-map-paths %swift_src_root /^src -scanner-prefix-map-paths %t /^tmp \
+// RUN:   -scanner-prefix-map-paths %t/header-2 /^header \
+// RUN:   -scanner-output-dir %t/header-2 -import-objc-header %t/header-2/Bridging.h
+
+// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps-1.json bridgingHeader:Test includeTree > %t/includeTree-1.casid
+// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps-2.json bridgingHeader:Test includeTree > %t/includeTree-2.casid
+// RUN: diff %t/includeTree-1.casid %t/includeTree-2.casid
+
+// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps-1.json Test casFSRootID > %t/root-1.casid
+// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps-2.json Test casFSRootID > %t/root-2.casid
+// RUN: diff %t/root-1.casid %t/root-2.casid
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps-1.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps-1.json bridgingHeader > %t/header.cmd
+// RUN: %target-swift-frontend @%t/header.cmd /^header/Bridging.h -disable-implicit-swift-modules -O -o %t/bridging.pch
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
+// RUN:   %target-swift-frontend @%t/header.cmd /^header/Bridging.h -disable-implicit-swift-modules -O -o %t/bridging.pch > %t/keys.json
+// RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json > %t/key
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps-1.json Test > %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-string-processing-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-concurrency-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-swift-modules\"" >> %t/MyApp.cmd
+// RUN: echo "\"-import-objc-header\"" >> %t/MyApp.cmd
+// RUN: echo "\"/^header/Bridging.h\"" >> %t/MyApp.cmd
+// RUN: echo "\"-import-pch\"" >> %t/MyApp.cmd
+// RUN: echo "\"%t/bridging.pch\"" >> %t/MyApp.cmd
+// RUN: echo "\"-bridging-header-pch-key\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/key\"" >> %t/MyApp.cmd
+// RUN: echo "\"-explicit-swift-module-map-file\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/map.casid\"" >> %t/MyApp.cmd
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps-1.json > %t/map.json
+// RUN: llvm-cas --cas %t/cas --make-blob --data %t/map.json > %t/map.casid
+// RUN: %target-swift-frontend  -cache-compile-job -module-name Test -O -cas-path %t/cas @%t/MyApp.cmd /^tmp/test.swift \
+// RUN:   -emit-module -o %t/Test.swiftmodule
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name User -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/user.swift -o %t/deps-3.json -auto-bridging-header-chaining -cache-compile-job -cas-path %t/cas \
+// RUN:   -scanner-prefix-map-paths %swift_src_root /^src -scanner-prefix-map-paths %t /^tmp \
+// RUN:   -scanner-prefix-map-paths %t/header-1 /^header \
+// RUN:   -scanner-output-dir %t/header-1 -I %t
+
+// RUN: %swift-scan-test -action get_chained_bridging_header -- %target-swift-frontend -scan-dependencies\
+// RUN:   -module-name User -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/user.swift -o %t/deps-3.json -auto-bridging-header-chaining -cache-compile-job -cas-path %t/cas \
+// RUN:   -scanner-prefix-map-paths %swift_src_root /^src -scanner-prefix-map-paths %t /^tmp \
+// RUN:   -scanner-prefix-map-paths %t/header-1 /^header \
+// RUN:   -scanner-output-dir %t/header-1 -I %t > %t/bridging-header1.h
+// RUN: %FileCheck %s --input-file=%t/bridging-header1.h --check-prefix=HEADER
+
+// HEADER: # 1 "<module-Test-embedded-bridging-header>" 1
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name User -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/user.swift -o %t/deps-4.json -auto-bridging-header-chaining -cache-compile-job -cas-path %t/cas \
+// RUN:   -scanner-prefix-map-paths %swift_src_root /^src -scanner-prefix-map-paths %t /^tmp \
+// RUN:   -scanner-prefix-map-paths %t/header-2 /^header \
+// RUN:   -scanner-output-dir %t/header-2 -I %t
+
+// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps-3.json bridgingHeader:Test includeTree > %t/includeTree-3.casid
+// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps-4.json bridgingHeader:Test includeTree > %t/includeTree-4.casid
+// RUN: diff %t/includeTree-3.casid %t/includeTree-4.casid
+
+
+
+//--- test.swift
+public func test() {
+    b()
+}
+
+//--- user.swift
+import Test
+
+//--- header-1/Bridging.h
+#include "Foo.h"
+//--- header-1/Foo.h
+void b(void);
+//--- header-2/Bridging.h
+#include "Foo.h"
+//--- header-2/Foo.h
+void b(void);
diff --git a/test/CAS/bridging-header.swift b/test/CAS/bridging-header.swift
index b0bdb8db75a2c..d55a3562d8502 100644
--- a/test/CAS/bridging-header.swift
+++ b/test/CAS/bridging-header.swift
@@ -41,9 +41,9 @@
 // RUN: llvm-cas --cas %t/cas --make-blob --data %t/map.json > %t/map.casid
 
 // RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json bridgingHeader > %t/header.cmd
-// RUN: %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules -O -o %t/bridging.pch
+// RUN: %target-swift-frontend @%t/header.cmd %t/Bridging.h -disable-implicit-swift-modules -O -o %t/bridging.pch
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
-// RUN:   %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules -O -o %t/bridging.pch > %t/keys.json
+// RUN:   %target-swift-frontend @%t/header.cmd %t/Bridging.h -disable-implicit-swift-modules -O -o %t/bridging.pch > %t/keys.json
 // RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json > %t/key
 
 // RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json Test > %t/MyApp.cmd
diff --git a/test/CAS/cache_key_compute.swift b/test/CAS/cache_key_compute.swift
index c348cb413f616..c60e4e3db2456 100644
--- a/test/CAS/cache_key_compute.swift
+++ b/test/CAS/cache_key_compute.swift
@@ -50,14 +50,6 @@
 // RUN: diff %t5.casid %t6.casid
 // RUN: not diff %t5.casid %t7.casid
 
-/// Check switching CAS plugin path.
-// RUN: %cache-tool -cas-path %t/cas -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext -cache-tool-action print-base-key -- \
-// RUN:   %target-swift-frontend -cache-compile-job %t/a.swift -c @%t/MyApp.cmd -cas-path %t/cas -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext > %t8.casid
-// RUN: ln -s %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext %t/libCASPluginTest%llvm_plugin_ext
-// RUN: %cache-tool -cas-path %t/cas -cas-plugin-path %t/libCASPluginTest%llvm_plugin_ext -cache-tool-action print-base-key -- \
-// RUN:   %target-swift-frontend -cache-compile-job %t/a.swift -c @%t/MyApp.cmd -cas-path %t/cas -cas-plugin-path %t/libCASPluginTest%llvm_plugin_ext > %t9.casid
-// RUN: diff %t8.casid %t9.casid
-
 /// Test output keys.
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
 // RUN:   %target-swift-frontend -cache-compile-job %t/a.swift -emit-module -c -emit-dependencies \
@@ -66,19 +58,33 @@
 /// Test plugin CAS.
 // RUN: %target-swift-frontend -scan-dependencies -module-name Test -O \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
-// RUN:   %t/a.swift -o %t/plugin_deps.json -cache-compile-job -cas-path %t/cas -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext \
+// RUN:   %t/a.swift -o %t/plugin_deps.json -cache-compile-job -cas-path %t/cas-plugin -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext \
 // RUN:   -cas-plugin-option first-prefix=myfirst-
 
 // RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/plugin_deps.json > %t/plugin_map.json
 // RUN: llvm-cas --cas %t/cas --make-blob --data %t/plugin_map.json > %t/map.casid
 
 // RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/plugin_deps.json Test > %t/plugin_MyApp.cmd
-// RUN: %cache-tool -cas-path %t/cas -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext \
+// RUN: %cache-tool -cas-path %t/cas-plugin -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext \
 // RUN:   -cas-plugin-option first-prefix=myfirst- -cache-tool-action print-output-keys -- \
 // RUN:   %target-swift-frontend -cache-compile-job %t/a.swift -emit-module -c -emit-dependencies \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   -emit-tbd -emit-tbd-path %t/test.tbd -o %t/test.o @%t/plugin_MyApp.cmd | %FileCheck %s --check-prefix=CHECK --check-prefix=PLUGIN
 
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/plugin_deps.json Test > %t/MyApp-plugin.cmd
+// RUN: echo "\"-disable-implicit-string-processing-module-import\"" >> %t/MyApp-plugin.cmd
+// RUN: echo "\"-disable-implicit-concurrency-module-import\"" >> %t/MyApp-plugin.cmd
+// RUN: echo "\"-parse-stdlib\"" >> %t/MyApp-plugin.cmd
+
+/// Check switching CAS plugin path.
+// RUN: %cache-tool -cas-path %t/cas-plugin -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext -cas-plugin-option first-prefix=myfirst- -cache-tool-action print-base-key -- \
+// RUN:   %target-swift-frontend -cache-compile-job %t/a.swift -c @%t/MyApp-plugin.cmd -cas-path %t/cas-plugin -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext > %t8.casid
+// RUN: ln -s %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext %t/libCASPluginTest%llvm_plugin_ext
+// RUN: %cache-tool -cas-path %t/cas-plugin -cas-plugin-path %t/libCASPluginTest%llvm_plugin_ext -cas-plugin-option first-prefix=myfirst- -cache-tool-action print-base-key -- \
+// RUN:   %target-swift-frontend -cache-compile-job %t/a.swift -c @%t/MyApp-plugin.cmd -cas-path %t/cas-plugin -cas-plugin-path %t/libCASPluginTest%llvm_plugin_ext > %t9.casid
+// RUN: diff %t8.casid %t9.casid
+
+
 // CHECK: "Input": "{{.*}}{{/|\\}}a.swift"
 // CHECK-NEXT: "CacheKey"
 // PLUGIN-SAME: myfirst-llvmcas://
diff --git a/test/CAS/cache_replay_mccas.swift b/test/CAS/cache_replay_mccas.swift
index bdc0f0f3cd09a..385e14e6796b8 100644
--- a/test/CAS/cache_replay_mccas.swift
+++ b/test/CAS/cache_replay_mccas.swift
@@ -37,16 +37,16 @@
 // RUN: test -f %t/Test.swiftmodule
 
 /// Expect cache miss a subset of outputs.
-// RUN %target-swift-frontend -cache-compile-job -cas-backend -cas-backend-mode=verify -Rcache-compile-job %t/test.swift -O -emit-module -emit-module-path %t/Test.swiftmodule -c \
-// RUN  -module-name Test -o %t/test.o -cas-path %t/cas @%t/MyApp.cmd 2>&1 | %FileCheck --check-prefix=CACHE-MISS %s
+// RUN: %target-swift-frontend -cache-compile-job -cas-backend -cas-backend-mode=verify -Rcache-compile-job %t/test.swift -O -emit-module -emit-module-path %t/Test.swiftmodule -c \
+// RUN:  -module-name Test -o %t/test.o -cas-path %t/cas @%t/MyApp.cmd 2>&1 | %FileCheck --check-prefix=CACHE-MISS %s
 
 /// Cache hit for retry.
-// RUN %target-swift-frontend -cache-compile-job -cas-backend -cas-backend-mode=verify -Rcache-compile-job %t/test.swift -O -emit-module -emit-module-path %t/Test.swiftmodule -c \
-// RUN  -module-name Test -o %t/test.o -cas-path %t/cas @%t/MyApp.cmd 2>&1 | %FileCheck --check-prefix=CACHE-HIT %s
+// RUN: %target-swift-frontend -cache-compile-job -cas-backend -cas-backend-mode=verify -Rcache-compile-job %t/test.swift -O -emit-module -emit-module-path %t/Test.swiftmodule -c \
+// RUN:  -module-name Test -o %t/test.o -cas-path %t/cas @%t/MyApp.cmd 2>&1 | %FileCheck --check-prefix=CACHE-HIT %s
 
 /// Skip cache
-// RUN %target-swift-frontend -cache-compile-job -cas-backend -cas-backend-mode=verify -Rcache-compile-job -cache-disable-replay %t/test.swift -O -emit-module -emit-module-path %t/Test.swiftmodule -c \
-// RUN  -module-name Test -o %t/test.o -cas-path %t/cas @%t/MyApp.cmd 2>&1 | %FileCheck --allow-empty --check-prefix=SKIP-CACHE %s
+// RUN: %target-swift-frontend -cache-compile-job -cas-backend -cas-backend-mode=verify -Rcache-compile-job -cache-disable-replay %t/test.swift -O -emit-module -emit-module-path %t/Test.swiftmodule -c \
+// RUN:  -module-name Test -o %t/test.o -cas-path %t/cas @%t/MyApp.cmd 2>&1 | %FileCheck --allow-empty --check-prefix=SKIP-CACHE %s
 
 // CACHE-MISS: remark: cache miss for input
 // CACHE-HIT: remark: replay output file '<cached-diagnostics>': key 'llvmcas://{{.*}}'
diff --git a/test/CAS/cached_diagnostics.swift b/test/CAS/cached_diagnostics.swift
index 8f5422f34c895..7457425423030 100644
--- a/test/CAS/cached_diagnostics.swift
+++ b/test/CAS/cached_diagnostics.swift
@@ -8,9 +8,9 @@
 // RUN: %swift_frontend_plain @%t/shim.cmd
 
 // RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json bridgingHeader > %t/header.cmd
-// RUN: %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules -O -o %t/objc.pch 2>&1 | %FileCheck %s -check-prefix CHECK-BRIDGE
+// RUN: %target-swift-frontend @%t/header.cmd %S/Inputs/objc.h -disable-implicit-swift-modules -O -o %t/objc.pch 2>&1 | %FileCheck %s -check-prefix CHECK-BRIDGE
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
-// RUN:   %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules -O -o %t/objc.pch > %t/keys.json
+// RUN:   %target-swift-frontend @%t/header.cmd %S/Inputs/objc.h -disable-implicit-swift-modules -O -o %t/objc.pch > %t/keys.json
 // RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json > %t/key
 
 // RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps.json > %t/map.json
diff --git a/test/CAS/cached_diagnostics_empty_filename.swift b/test/CAS/cached_diagnostics_empty_filename.swift
index c196977eed694..7100781a933fd 100644
--- a/test/CAS/cached_diagnostics_empty_filename.swift
+++ b/test/CAS/cached_diagnostics_empty_filename.swift
@@ -1,4 +1,3 @@
-// REQUIRES: swift_feature_RegionBasedIsolation
 // REQUIRES: objc_interop
 
 // RUN: %empty-directory(%t)
@@ -36,7 +35,7 @@
 // RUN: echo "\"@%t/map.casid\"" >> %t/MyApp.cmd
 
 // RUN: %target-swift-frontend  -cache-compile-job -module-name Test -O -cas-path %t/cas @%t/MyApp.cmd %t/test.swift \
-// RUN:   -emit-module -o %t/test.swiftmodule -require-explicit-sendable -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
+// RUN:   -emit-module -o %t/test.swiftmodule -require-explicit-sendable -strict-concurrency=complete
 
 //--- module.modulemap
 module A {
diff --git a/test/CAS/cached_diagnostics_remap.swift b/test/CAS/cached_diagnostics_remap.swift
index 8d80802a0d2f9..792b97ff72e1e 100644
--- a/test/CAS/cached_diagnostics_remap.swift
+++ b/test/CAS/cached_diagnostics_remap.swift
@@ -4,14 +4,14 @@
 /// Check path remapping.
 // RUN: %target-swift-frontend -scan-dependencies -module-name Test -O -import-objc-header %t/objc.h -auto-bridging-header-chaining \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
-// RUN:   %t/test.swift -o %t/deps.json -cache-compile-job -cas-path %t/cas -scanner-prefix-map %t=/^test -scanner-output-dir %t.noremap
+// RUN:   %t/test.swift -o %t/deps.json -cache-compile-job -cas-path %t/cas -scanner-prefix-map-paths %t /^test -scanner-output-dir %t.noremap
 
 // RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json bridgingHeader > %t/header.cmd
-// RUN: %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules -O -o %t/objc.pch 2>&1 | %FileCheck %s -check-prefix BRIDGE
+// RUN: %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules /^test/objc.h -O -o %t/objc.pch 2>&1 | %FileCheck %s -check-prefix BRIDGE
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
-// RUN:   %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules -O -o %t/objc.pch > %t/keys.json
+// RUN:   %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules /^test/objc.h -O -o %t/objc.pch > %t/keys.json
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action render-diags %t/keys.json -- \
-// RUN:    %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules -O -o %t/objc.pch -cache-replay-prefix-map /^test=%t 2>&1 \
+// RUN:    %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules /^test/objc.h -O -o %t/objc.pch -cache-replay-prefix-map /^test %t 2>&1 \
 // RUN:    | %FileCheck %s -check-prefix BRIDGE -check-prefix BRIDGE-REMAP
 
 // RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json > %t/key
@@ -33,7 +33,7 @@
 // RUN:   -emit-module -o %t/test.swiftmodule /^test/test.swift > %t/cache_key.json
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action render-diags %t/cache_key.json -- %target-swift-frontend -cache-compile-job -module-name Test \
 // RUN:   -O -cas-path %t/cas @%t/MyApp.cmd \
-// RUN:   -emit-module -o %t/test.swiftmodule /^test/test.swift -cache-replay-prefix-map /^test=%t 2>&1 | %FileCheck %s --check-prefix REMAP
+// RUN:   -emit-module -o %t/test.swiftmodule /^test/test.swift -cache-replay-prefix-map /^test %t 2>&1 | %FileCheck %s --check-prefix REMAP
 
 // BRIDGE: /^test/objc.h:3:2: warning: warning in bridging header
 // BRIDGE-REMAP: BUILD_DIR{{.*}}{{/|\\}}objc.h:3:2: warning: warning in bridging header
diff --git a/test/CAS/cas_fs.swift b/test/CAS/cas_fs.swift
deleted file mode 100644
index a4b0e2cab6ea5..0000000000000
--- a/test/CAS/cas_fs.swift
+++ /dev/null
@@ -1,28 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: mkdir -p %t/empty
-// RUN: mkdir -p %t/cas
-
-// RUN: llvm-cas --cas %t/cas --ingest %t/empty > %t/empty.casid
-// RUN: not %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/empty.casid -cas-path %t/cas %s 2>&1 | %FileCheck %s --check-prefix NO-INPUTS
-// NO-INPUTS: error: error opening input file
-
-// RUN: llvm-cas --cas %t/cas --ingest %s > %t/source.casid
-// RUN: not %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/source.casid -cas-path %t/cas %s 2>&1 | %FileCheck %s --check-prefix NO-RESOURCES
-// NO-RESOURCES: error: unable to load standard library
-
-/// Ingest the resource directory to satisfy the file system requirement. Also switch CWD to resource dir.
-// RUN: llvm-cas --cas %t/cas --merge @%t/source.casid %test-resource-dir > %t/full.casid
-// RUN: cd %test-resource-dir
-// RUN: %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/full.casid -cas-path %t/cas %s
-
-/// Try clang importer.
-// RUN: not %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/full.casid -cas-path %t/cas %s -import-objc-header %S/Inputs/objc.h 2>&1 | %FileCheck %s --check-prefix NO-BRIDGING-HEADER
-// NO-BRIDGING-HEADER: error: bridging header
-
-// RUN: llvm-cas --cas %t/cas --merge @%t/full.casid %S/Inputs/objc.h > %t/bridging_header.casid
-// RUN: %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/bridging_header.casid -cas-path %t/cas %s -import-objc-header %S/Inputs/objc.h
-
-/// Clean the CAS to save space.
-// RUN: %empty-directory(%t)
-
-func testFunc() {}
diff --git a/test/CAS/cas_output_backend.swift b/test/CAS/cas_output_backend.swift
index 603bc5d58adbb..0120ea00174be 100644
--- a/test/CAS/cas_output_backend.swift
+++ b/test/CAS/cas_output_backend.swift
@@ -2,7 +2,7 @@
 // RUN: mkdir -p %t/cas
 
 // RUN: not %target-swift-frontend -c -cache-compile-job -cas-path %t/cas %s -o %t/test.o 2>&1 | %FileCheck %s --check-prefix=NO-CASFS
-// NO-CASFS: caching is enabled without -cas-fs option
+// NO-CASFS: caching is enabled without CAS file-system options
 
 // RUN: %target-swift-frontend -scan-dependencies -module-name Test -O \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
@@ -13,6 +13,9 @@
 // RUN: echo "\"-disable-implicit-concurrency-module-import\"" >> %t/MyApp.cmd
 // RUN: echo "\"-parse-stdlib\"" >> %t/MyApp.cmd
 
+// RUN: not %target-swift-frontend -c -cache-compile-job %s -o %t/test.o @%t/MyApp.cmd 2>&1 | %FileCheck %s --check-prefix=NOT-CONFIG
+// NOT-CONFIG: error: CAS cannot be initialized from the specified '-cas-*' options: no CAS options provided
+
 // RUN: %target-swift-frontend -c -cache-compile-job -cas-path %t/cas %s -o %t/test.o @%t/MyApp.cmd
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
 // RUN:   %target-swift-frontend -c -cache-compile-job -cas-path %t/cas %s -o %t/test.o @%t/MyApp.cmd > %t/cache_key.json
diff --git a/test/CAS/coverage-dir.swift b/test/CAS/coverage-dir.swift
new file mode 100644
index 0000000000000..69d79c94831fb
--- /dev/null
+++ b/test/CAS/coverage-dir.swift
@@ -0,0 +1,28 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -O -I %t/include \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/main.swift -o %t/deps.json -cache-compile-job -cas-path %t/cas -profile-coverage-mapping -profile-generate
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json A > %t/A.cmd
+// RUN: %swift_frontend_plain @%t/A.cmd
+
+// RUN: %FileCheck %s --input-file=%t/shim.cmd
+// RUN: %FileCheck %s --input-file=%t/A.cmd
+
+// CHECK: -direct-clang-cc1-module-build
+// CHECK-NOT: -fcoverage-compilation-dir
+
+//--- main.swift
+import A
+func test() {
+  a();
+}
+
+//--- include/A.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name A -O -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib -user-module-version 1.0
+public func a() { }
diff --git a/test/CAS/debug_info_pcm.swift b/test/CAS/debug_info_pcm.swift
new file mode 100644
index 0000000000000..2bd1f56b8eb43
--- /dev/null
+++ b/test/CAS/debug_info_pcm.swift
@@ -0,0 +1,43 @@
+// REQUIRES: OS=macosx
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/test.swift -o %t/deps.json -cache-compile-job -cas-path %t/cas -I %t/include
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:B > %t/B.cmd
+// RUN: %swift_frontend_plain @%t/B.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:A > %t/A.cmd
+// RUN: %swift_frontend_plain @%t/A.cmd
+// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps.json clang:A modulePath > %t/A.path
+
+// RUN: dwarfdump --debug-info @%t/A.path | %FileCheck %s
+
+// CHECK: DW_AT_GNU_dwo_name
+// CHECK-SAME: BUILD_DIR
+
+//--- test.swift
+import A
+
+//--- include/a.h
+#include "b.h"
+struct A {
+  int a;
+};
+
+//--- include/b.h
+void b(void);
+
+//--- include/module.modulemap
+module A {
+  header "a.h"
+  export *
+}
+
+module B {
+  header "b.h"
+  export *
+}
diff --git a/test/CAS/dependency_file.swift b/test/CAS/dependency_file.swift
index b4f279c555be3..e760c7648665f 100644
--- a/test/CAS/dependency_file.swift
+++ b/test/CAS/dependency_file.swift
@@ -38,7 +38,7 @@
 // RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   %t/main.swift -o %t/deps-1.json -swift-version 5 -cache-compile-job -cas-path %t/cas -I %t/include -sdk %t/sdk \
-// RUN:   -scanner-prefix-map %swift_src_root=/^src -scanner-prefix-map %t=/^tmp -scanner-prefix-map %t/sdk=/^sdk
+// RUN:   -scanner-prefix-map-paths %swift_src_root /^src -scanner-prefix-map-paths %t /^tmp -scanner-prefix-map-paths %t/sdk /^sdk
 // RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps-1.json A > %t/A1.cmd
 // RUN: %swift_frontend_plain @%t/A1.cmd
 // RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps-1.json > %t/map-1.json
@@ -50,7 +50,7 @@
 // RUN:   -swift-version 5 -disable-implicit-swift-modules \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
-// RUN:   -cache-replay-prefix-map /^src=%swift_src_root -cache-replay-prefix-map /^tmp=%t -cache-replay-prefix-map /^sdk=%t/sdk \
+// RUN:   -cache-replay-prefix-map /^src %swift_src_root -cache-replay-prefix-map /^tmp %t -cache-replay-prefix-map /^sdk %t/sdk \
 // RUN:   /^tmp/main.swift @%t/MyApp-1.cmd -emit-dependencies -emit-dependencies-path %t/main-3.d
 
 // RUN: %FileCheck %s --check-prefix=DEPS3 --input-file=%t/main-3.d -DTMP=%t
@@ -63,7 +63,7 @@
 // RUN:   -swift-version 5 -disable-implicit-swift-modules \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
-// RUN:   -cache-replay-prefix-map /^src=%swift_src_root -cache-replay-prefix-map /^tmp=%t -cache-replay-prefix-map /^sdk=%t/sdk \
+// RUN:   -cache-replay-prefix-map /^src %swift_src_root -cache-replay-prefix-map /^tmp %t -cache-replay-prefix-map /^sdk %t/sdk \
 // RUN:   /^tmp/main.swift @%t/MyApp-1.cmd -emit-dependencies -emit-dependencies-path %t/main-4.d > %t/key.casid
 
 // RUN: %swift-scan-test -action replay_result -cas-path %t/cas -id @%t/key.casid -- \
@@ -72,7 +72,7 @@
 // RUN:   -swift-version 5 -disable-implicit-swift-modules \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
-// RUN:   -cache-replay-prefix-map /^src=%swift_src_root -cache-replay-prefix-map /^tmp=%t -cache-replay-prefix-map /^sdk=%t/sdk \
+// RUN:   -cache-replay-prefix-map /^src %swift_src_root -cache-replay-prefix-map /^tmp %t -cache-replay-prefix-map /^sdk %t/sdk \
 // RUN:   /^tmp/main.swift @%t/MyApp-1.cmd -emit-dependencies -emit-dependencies-path %t/main-4.d 2>&1 | %FileCheck %s --check-prefix=CACHE-HIT4
 // CACHE-HIT4: remark: replay output file '{{.*}}{{/|\\}}main-4.d': key 'llvmcas://{{.*}}'
 // RUN: %FileCheck %s --check-prefix=DEPS4 --input-file=%t/main-4.d -DTMP=%t
diff --git a/test/CAS/macro_plugin_external.swift b/test/CAS/macro_plugin_external.swift
index f4688ba9f1904..a30da29ab3cac 100644
--- a/test/CAS/macro_plugin_external.swift
+++ b/test/CAS/macro_plugin_external.swift
@@ -43,19 +43,110 @@
 // RUN: %target-swift-frontend \
 // RUN:   -typecheck -verify -cache-compile-job -cas-path %t/cas \
 // RUN:   -swift-version 5 -disable-implicit-swift-modules \
-// RUN:   -external-plugin-path %t/plugins/#%swift-plugin-server \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
 // RUN:   -module-name MyApp -explicit-swift-module-map-file @%t/map.casid \
 // RUN:   %t/macro.swift @%t/MyApp.cmd
 
+// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-serialized -module-name MyApp -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/macro.swift -o %t/deps2.json -swift-version 5 -cache-compile-job -cas-path %t/cas -external-plugin-path %t/plugins#%swift-plugin-server \
+// RUN:   -scanner-prefix-map-paths %t /^test -scanner-prefix-map-paths %swift-bin-dir /^bin -resolved-plugin-verification
+
+// RUN: %S/Inputs/SwiftDepsExtractor.py %t/deps2.json MyApp casFSRootID > %t/fs.casid
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-include-tree-list @%t/fs.casid | %FileCheck %s --check-prefix=FS-REMAP -DLIB=%target-library-name(MacroDefinition)
+
+/// CASFS is remapped.
+// FS-REMAP: /^test/plugins/[[LIB]]
+
+// RUN: %S/Inputs/BuildCommandExtractor.py %t/deps2.json clang:SwiftShims > %t/SwiftShims2.cmd
+// RUN: %swift_frontend_plain @%t/SwiftShims2.cmd
+
+// RUN: %S/Inputs/BuildCommandExtractor.py %t/deps2.json MyApp > %t/MyApp2.cmd
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps2.json > %t/map2.json
+// RUN: llvm-cas --cas %t/cas --make-blob --data %t/map2.json > %t/map2.casid
+
+/// Command-line is remapped.
+// RUN: %FileCheck %s --check-prefix=CMD-REMAP --input-file=%t/MyApp2.cmd -DLIB=%target-library-name(MacroDefinition)
+
+// CMD-REMAP: -resolved-plugin-verification
+// CMD-REMAP-NEXT: -load-resolved-plugin
+// CMD-REMAP-NEXT: /^test/plugins/[[LIB]]#/^bin/swift-plugin-server#MacroDefinition
+
+// RUN: %target-swift-frontend \
+// RUN:   -emit-module -o %t/Macro.swiftmodule -cache-compile-job -cas-path %t/cas \
+// RUN:   -emit-module-interface-path %t/Macro.swiftinterface \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -module-name MyApp -explicit-swift-module-map-file @%t/map2.casid -Rmacro-loading -Rcache-compile-job \
+// RUN:   /^test/macro.swift @%t/MyApp2.cmd -cache-replay-prefix-map /^test %t -cache-replay-prefix-map /^bin %swift-bin-dir 2>&1 | %FileCheck %s --check-prefix=REMARK
+// REMAKR: remark: cache miss
+// REMARK: remark: loaded macro implementation module 'MacroDefinition' from compiler plugin server
+
+/// Encoded PLUGIN_SEARCH_OPTION is remapped.
+// RUN: llvm-bcanalyzer -dump %t/Macro.swiftmodule | %FileCheck %s --check-prefix=MOD -DLIB=%target-library-name(MacroDefinition)
+
+// MOD: <PLUGIN_SEARCH_OPTION abbrevid=7 op0=4/> blob data = '/^test/plugins/[[LIB]]#/^bin/swift-plugin-server#MacroDefinition'
+
+/// Cache hit has no macro-loading remarks because no macro is actually loaded and the path might not be correct due to different mapping.
+// RUN: %target-swift-frontend \
+// RUN:   -emit-module -o %t/Macro.swiftmodule -cache-compile-job -cas-path %t/cas \
+// RUN:   -emit-module-interface-path %t/Macro.swiftinterface \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -module-name MyApp -explicit-swift-module-map-file @%t/map2.casid -Rmacro-loading -Rcache-compile-job \
+// RUN:   /^test/macro.swift @%t/MyApp2.cmd -cache-replay-prefix-map /^test %t -cache-replay-prefix-map /^bin %swift-bin-dir 2>&1 | %FileCheck %s --check-prefix=NO-REMARK
+// NO-REMARK: remark: replay output file
+// NO-REMARK-NOT: remark: loaded macro implementation module 'MacroDefinition' from compiler plugin server
+
+/// Update timestamp, the build should still work.
+// RUN: touch %t/plugins/%target-library-name(MacroDefinition)
+// RUN: %target-swift-frontend \
+// RUN:   -emit-module -o %t/Macro.swiftmodule -cache-compile-job -cas-path %t/cas \
+// RUN:   -emit-module-interface-path %t/Macro.swiftinterface \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -module-name MyApp -explicit-swift-module-map-file @%t/map2.casid -Rmacro-loading -Rcache-compile-job -cache-disable-replay \
+// RUN:   /^test/macro.swift @%t/MyApp2.cmd -cache-replay-prefix-map /^test %t -cache-replay-prefix-map /^bin %swift-bin-dir
+
+/// Typecheck swift interface with macro plugin.
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
+// RUN:   %target-swift-frontend \
+// RUN:   -emit-module -o %t/Macro.swiftmodule -cache-compile-job -cas-path %t/cas \
+// RUN:   -emit-module-interface-path %t/Macro.swiftinterface \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -module-name MyApp -explicit-swift-module-map-file @%t/map2.casid -Rmacro-loading -Rcache-compile-job -cache-disable-replay \
+// RUN:   /^test/macro.swift @%t/MyApp2.cmd -cache-replay-prefix-map /^test %t -cache-replay-prefix-map /^bin %swift-bin-dir > %t/keys.json
+// RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json /^test/macro.swift > %t/key
+
+// RUN: %target-swift-frontend \
+// RUN:   -typecheck-module-from-interface %t/Macro.swiftinterface \
+// RUN:   -cache-compile-job -cas-path %t/cas \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -module-name MyApp -explicit-swift-module-map-file @%t/map2.casid -Rmacro-loading -Rcache-compile-job -cache-disable-replay \
+// RUN:   @%t/MyApp2.cmd -cache-replay-prefix-map /^test %t -cache-replay-prefix-map /^bin %swift-bin-dir \
+// RUN:   -input-file-key @%t/key
+
+/// Change the dylib content, this will fail the build.
+// RUN: echo " " >> %t/plugins/%target-library-name(MacroDefinition)
+// RUN: not %target-swift-frontend \
+// RUN:   -emit-module -o %t/Macro.swiftmodule -cache-compile-job -cas-path %t/cas \
+// RUN:   -emit-module-interface-path %t/Macro.swiftinterface \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -module-name MyApp -explicit-swift-module-map-file @%t/map2.casid -Rmacro-loading -Rcache-compile-job -cache-disable-replay \
+// RUN:   /^test/macro.swift @%t/MyApp2.cmd -cache-replay-prefix-map /^test %t -cache-replay-prefix-map /^bin %swift-bin-dir 2>&1 | %FileCheck %s --check-prefix=FAILED
+// FAILED: plugin has changed since dependency scanning
+
 //--- nomacro.swift
 func test() {}
 
 //--- macro.swift
 @attached(extension, conformances: P, names: named(requirement))
-macro DelegatedConformance() = #externalMacro(module: "MacroDefinition", type: "DelegatedConformanceViaExtensionMacro")
+public macro DelegatedConformance() = #externalMacro(module: "MacroDefinition", type: "DelegatedConformanceViaExtensionMacro")
 
-protocol P {
+public protocol P {
   static func requirement()
 }
 
diff --git a/test/CAS/module_deps.swift b/test/CAS/module_deps.swift
deleted file mode 100644
index 509f3d2984b3b..0000000000000
--- a/test/CAS/module_deps.swift
+++ /dev/null
@@ -1,197 +0,0 @@
-// REQUIRES: objc_interop
-
-// RUN: %empty-directory(%t)
-// RUN: mkdir -p %t/clang-module-cache
-// RUN: mkdir -p %t/cas
-
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -enable-cross-import-overlays -cache-compile-job -cas-path %t/cas -no-clang-include-tree -scanner-output-dir %t -auto-bridging-header-chaining
-// Check the contents of the JSON output
-// RUN: %validate-json %t/deps.json &>/dev/null
-// RUN: %FileCheck -check-prefix CHECK -check-prefix CHECK_NO_CLANG_TARGET %s < %t/deps.json
-
-// Check the contents of the JSON output
-// RUN: %FileCheck %s -check-prefix CHECK -check-prefix CHECK-NO-SEARCH-PATHS < %t/deps.json
-
-// Check the make-style dependencies file
-// RUN: %FileCheck %s -check-prefix CHECK-MAKE-DEPS < %t/deps.d
-
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -test-dependency-scan-cache-serialization -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -enable-cross-import-overlays -cache-compile-job -cas-path %t/cas -no-clang-include-tree -scanner-output-dir %t -auto-bridging-header-chaining
-// RUN: %validate-json %t/deps.json &>/dev/null
-// RUN: %FileCheck -check-prefix CHECK -check-prefix CHECK_NO_CLANG_TARGET %s < %t/deps.json
-
-// Ensure that scanning with `-clang-target` makes sure that Swift modules' respective PCM-dependency-build-argument sets do not contain target triples.
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -module-cache-path %t/clang-module-cache %s -o %t/deps_clang_target.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -enable-cross-import-overlays -clang-target %target-cpu-apple-macosx10.14 -cache-compile-job -cas-path %t/cas -no-clang-include-tree
-
-/// check cas-fs content
-// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps.json E casFSRootID > %t/E_fs.casid
-// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-include-tree-list @%t/E_fs.casid | %FileCheck %s -check-prefix FS_ROOT_E
-// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps.json clang:F casFSRootID > %t/F_fs.casid
-// RUN: llvm-cas --cas %t/cas --ls-tree-recursive @%t/F_fs.casid | %FileCheck %s -check-prefix FS_ROOT_F
-
-// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps.json deps commandLine > %t/deps.cmd
-// RUN: %FileCheck %s -check-prefix MAIN_CMD -input-file=%t/deps.cmd
-
-// FS_ROOT_E-DAG: E.swiftinterface
-// FS_ROOT_E-DAG: SDKSettings.json
-
-// FS_ROOT_F: CHeaders/A.h
-// FS_ROOT_F: CHeaders/B.h
-// FS_ROOT_F: CHeaders/C.h
-// FS_ROOT_F: CHeaders/D.h
-// FS_ROOT_F: CHeaders/F.h
-// FS_ROOT_F: CHeaders/G.h
-// FS_ROOT_F: CHeaders/H.h
-// FS_ROOT_F: CHeaders/I.h
-// FS_ROOT_F: CHeaders/X.h
-// FS_ROOT_F: CHeaders/module.modulemap
-
-// MAIN_CMD: -direct-clang-cc1-module-build
-// MAIN_CMD: -cas-fs
-// MAIN_CMD-NOT: -clang-include-tree-root
-
-import C
-import E
-import G
-import SubE
-
-// CHECK: "mainModuleName": "deps"
-
-/// --------Main module
-// CHECK-LABEL: "modulePath": "deps.swiftmodule",
-// CHECK-NEXT: sourceFiles
-// CHECK-NEXT: module_deps.swift
-// CHECK-NEXT: ],
-// CHECK-NEXT: "directDependencies": [
-// CHECK-DAG:     "clang": "C"
-// CHECK-DAG:     "swift": "E"
-// CHECK-DAG:     "swift": "G"
-// CHECK-DAG:     "swift": "SubE"
-// CHECK-DAG:     "swift": "Swift"
-// CHECK-DAG:     "swift": "SwiftOnoneSupport"
-// CHECK-DAG:     "swift": "_Concurrency"
-// CHECK-DAG:     "swift": "_cross_import_E"
-// CHECK: ],
-// CHECK:      "commandLine":
-// CHECK:      "casFSRootID":
-// CHECK-NOT: "error: cannot open Swift placeholder dependency module map from"
-// CHECK: "bridgingHeader":
-// CHECK-NEXT: "path":
-// CHECK-SAME: Bridging.h
-
-// CHECK-NEXT: "sourceFiles":
-// CHECK-NEXT: ChainedBridgingHeader.h
-// CHECK-NEXT: Bridging.h
-// CHECK-NEXT: BridgingOther.h
-
-// CHECK: "moduleDependencies": [
-// CHECK-NEXT: "F"
-// CHECK-NEXT: ]
-
-// CHECK: "swiftOverlayDependencies": [
-// CHECK-DAG:     "swift": "A"
-// CHECK-DAG:     "swift": "F"
-
-/// --------Clang module C
-// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}C-{{.*}}.pcm",
-
-// CHECK: "sourceFiles": [
-// CHECK-DAG: module.modulemap
-// CHECK-DAG: C.h
-
-// CHECK: directDependencies
-// CHECK-NEXT: {
-// CHECK-NEXT: "clang": "B"
-
-// CHECK: "moduleMapPath"
-// CHECK-SAME: module.modulemap
-
-// CHECK: "contextHash"
-// CHECK-SAME: "{{.*}}"
-
-/// --------Clang module B
-// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}B-{{.*}}.pcm",
-// CHECK: "contextHash": "[[B_CONTEXT:.*]]",
-// CHECK: "-o"
-// CHECK-NEXT: B-{{.*}}[[B_CONTEXT]].pcm
-
-// Check make-style dependencies
-// CHECK-MAKE-DEPS: module_deps.swift
-// CHECK-MAKE-DEPS-SAME: A.swiftinterface
-// CHECK-MAKE-DEPS-SAME: G.swiftinterface
-// CHECK-MAKE-DEPS-SAME: B.h
-// CHECK-MAKE-DEPS-SAME: Bridging.h
-// CHECK-MAKE-DEPS-SAME: BridgingOther.h
-// CHECK-MAKE-DEPS-SAME: module.modulemap
-
-/// --------Swift module F
-// CHECK:      "modulePath": "{{.*}}{{/|\\}}F-{{.*}}.swiftmodule",
-// CHECK-NEXT: "sourceFiles": [
-// CHECK-NEXT: ],
-// CHECK-NEXT: "directDependencies": [
-// CHECK-NEXT:   {
-// CHECK-DAG:     "clang": "F"
-// CHECK-DAG:     "swift": "Swift"
-// CHECK-DAG:     "swift": "SwiftOnoneSupport"
-// CHECK-NEXT:   }
-// CHECK-NEXT: ],
-// CHECK: "details":
-// CHECK: "moduleCacheKey":
-
-/// --------Swift module A
-// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}A-{{.*}}.swiftmodule",
-
-// CHECK: directDependencies
-// CHECK-NEXT: {
-// CHECK-DAG:   "clang": "A"
-// CHECK-DAG:   "swift": "Swift"
-// CHECK-DAG:   "swift": "SwiftOnoneSupport"
-// CHECK-NEXT: }
-// CHECK: "details":
-// CHECK: "moduleCacheKey":
-
-/// --------Swift module G
-// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}G-{{.*}}.swiftmodule"
-// CHECK: "directDependencies"
-// CHECK-NEXT: {
-// CHECK-DAG:   "clang": "G"
-// CHECK-DAG:   "swift": "Swift"
-// CHECK-DAG:   "swift": "SwiftOnoneSupport"
-// CHECK: ],
-// CHECK-NEXT: "linkLibraries": [
-// CHECK: "details": {
-
-// CHECK: "commandLine": [
-// CHECK: "-compile-module-from-interface"
-// CHECK: "-target"
-// CHECK: "-cache-compile-job"
-// CHECK: "-cas-path"
-// CHECK: "-module-name"
-// CHECK: "G"
-// CHECK: "-swift-version"
-// CHECK: "5"
-// CHECK: ],
-// CHECK: "contextHash": "{{.*}}",
-
-/// --------Swift module E
-// CHECK: "swift": "E"
-// CHECK-LABEL: modulePath": "{{.*}}{{/|\\}}E-{{.*}}.swiftmodule"
-// CHECK: "directDependencies"
-// CHECK-NEXT: {
-// CHECK-NEXT: "swift": "Swift"
-
-// CHECK: "moduleInterfacePath"
-// CHECK-SAME: E.swiftinterface
-
-/// --------Swift module Swift
-// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}Swift-{{.*}}.swiftmodule",
-
-// CHECK: directDependencies
-// CHECK-NEXT: {
-// CHECK-NEXT: "clang": "SwiftShims"
-
-/// --------Clang module SwiftShims
-// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}SwiftShims-{{.*}}.pcm",
-// CHECK: "contextHash": "[[SHIMS_CONTEXT:.*]]",
-// CHECK: "-o"
-// CHECK-NEXT: SwiftShims-{{.*}}[[SHIMS_CONTEXT]].pcm
-// CHECK-NO-SEARCH-PATHS-NOT: "-prebuilt-module-cache-path"
diff --git a/test/CAS/module_deps_clang_extras.swift b/test/CAS/module_deps_clang_extras.swift
index b0950f6e23502..6415bf4aa49ed 100644
--- a/test/CAS/module_deps_clang_extras.swift
+++ b/test/CAS/module_deps_clang_extras.swift
@@ -4,46 +4,99 @@
 // RUN: mkdir -p %t/clang-module-cache
 // RUN: mkdir -p %t/cas
 // RUN: split-file %s %t
-// RUN: %hmaptool write %t/hmap.json %t/empty.hmap
+// RUN: sed "s|DIR|%/t|g" %t/hmap.json.template > %t/hmap.json
+// RUN: sed "s|DIR|%/t|g" %t/test.yaml.template > %t/test.yaml
+// RUN: %hmaptool write %t/hmap.json %t/test.hmap
 
 // RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache \
-// RUN:   %t/Test.swift -o %t/deps.json -cache-compile-job -cas-path %t/cas \
-// RUN:   -Xcc -fmodule-map-file=%t/module.modulemap -Xcc -ivfsoverlay -Xcc %t/empty.yaml \
-// RUN:   -Xcc -I%t/empty.hmap
+// RUN:   %t/Test.swift -module-name Test -o %t/deps.json -cache-compile-job -cas-path %t/cas \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -Xcc -fmodule-map-file=%t/include/module.modulemap -Xcc -ivfsoverlay -Xcc %t/test.yaml \
+// RUN:   -Xcc -I%t/test.hmap -module-load-mode prefer-serialized -scanner-output-dir %t \
+// RUN:   -import-objc-header %t/Bridge.h -auto-bridging-header-chaining
 // RUN: %validate-json %t/deps.json &>/dev/null
 
-// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps.json deps casFSRootID > %t/fs.casid
+// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps.json Test casFSRootID > %t/fs.casid
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-include-tree-list @%t/fs.casid | %FileCheck %s -DDIR=%basename_t -check-prefix FS_ROOT
-// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps.json clang:Dummy clangIncludeTree > %t/tree.casid
-// RUN: clang-cas-test --cas %t/cas --print-include-tree @%t/tree.casid | %FileCheck %s -DDIR=%basename_t -check-prefix INCLUDE_TREE
 
-// FS_ROOT: [[DIR]].tmp/empty.hmap
-// FS_ROOT: [[DIR]].tmp/empty.yaml
+// FS_ROOT: [[DIR]].tmp/hidden/Dummy.h
+// FS_ROOT: [[DIR]].tmp/hidden/a.h
+// FS_ROOT: [[DIR]].tmp/hidden/b.h
 
-// INCLUDE_TREE: [[DIR]].tmp/Dummy.h
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:Dummy > %t/dummy.cmd
+// RUN: %swift_frontend_plain @%t/dummy.cmd
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json bridgingHeader > %t/header.cmd
+// RUN: %target-swift-frontend @%t/header.cmd %t/Bridge.h -disable-implicit-swift-modules -O -o %t/objc.pch
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
+// RUN:   %target-swift-frontend @%t/header.cmd %t/Bridge.h -disable-implicit-swift-modules -O -o %t/objc.pch > %t/keys.json
+// RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json > %t/key
+
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps.json > %t/map.json
+// RUN: llvm-cas --cas %t/cas --make-blob --data %t/map.json > %t/map.casid
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json Test > %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-string-processing-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-concurrency-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-swift-modules\"" >> %t/MyApp.cmd
+// RUN: echo "\"-import-objc-header\"" >> %t/MyApp.cmd
+// RUN: echo "\"%t/objc.pch\"" >> %t/MyApp.cmd
+// RUN: echo "\"-bridging-header-pch-key\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/key\"" >> %t/MyApp.cmd
+// RUN: echo "\"-explicit-swift-module-map-file\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/map.casid\"" >> %t/MyApp.cmd
+
+// RUN: %target-swift-frontend  -cache-compile-job -module-name Test -O -cas-path %t/cas @%t/MyApp.cmd %t/Test.swift \
+// RUN:   -emit-module -o %t/test.swiftmodule
 
 //--- Test.swift
 import Dummy
 func test() {}
 
-//--- module.modulemap
+//--- Bridge.h
+#include "b.h"
+
+//--- hidden/module.modulemap
 module Dummy {
  umbrella header "Dummy.h"
 }
 
-//--- Dummy.h
+//--- hidden/Dummy.h
+#include "a.h"
 void dummy(void);
 
-//--- hmap.json
+//--- hidden/a.h
+/* empty file */
+
+//--- hidden/b.h
+/* empty file */
+
+//--- hmap.json.template
 {
-  "mappings": {} 
+  "mappings": {
+    "a.h": "DIR/hidden/a.h",
+    "b.h": "DIR/hidden/b.h"
+  }
 }
 
-//--- empty.yaml
+//--- test.yaml.template
 {
   "version": 0,
   "case-sensitive": "false",
   "use-external-names": true,
-  "roots": []
+  "roots": [
+    {
+      "type": "file",
+      "name": "DIR/include/module.modulemap",
+      "external-contents": "DIR/hidden/module.modulemap"
+    },
+    {
+      "type": "file",
+      "name": "DIR/include/Dummy.h",
+      "external-contents": "DIR/hidden/Dummy.h"
+    },
+  ]
 }
 
diff --git a/test/CAS/module_deps_include_tree.swift b/test/CAS/module_deps_include_tree.swift
index 711d84a680864..21a3f20afec3b 100644
--- a/test/CAS/module_deps_include_tree.swift
+++ b/test/CAS/module_deps_include_tree.swift
@@ -41,7 +41,6 @@
 // INCLUDE_TREE_F-NEXT: CHeaders/F.h
 
 // MAIN_CMD: -direct-clang-cc1-module-build
-// MAIN_CMD: -clang-include-tree-root
 // MAIN_CMD: -clang-include-tree-filelist
 
 import C
@@ -73,7 +72,6 @@ import SubE
 // CHECK-SAME: Bridging.h
 
 // CHECK-NEXT: "sourceFiles":
-// CHECK-NEXT: ChainedBridgingHeader.h
 // CHECK-NEXT: Bridging.h
 // CHECK-NEXT: BridgingOther.h
 
diff --git a/test/CAS/module_path_remap.swift b/test/CAS/module_path_remap.swift
index a8691ec8a096b..40648b749d3b4 100644
--- a/test/CAS/module_path_remap.swift
+++ b/test/CAS/module_path_remap.swift
@@ -7,7 +7,7 @@
 // RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps.json \
 // RUN:  -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -emit-dependencies \
 // RUN:  -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -cache-compile-job \
-// RUN:  -cas-path %t/cas -scanner-prefix-map %swift_src_root=/^src -scanner-prefix-map %t=/^tmp -scanner-output-dir %t -auto-bridging-header-chaining
+// RUN:  -cas-path %t/cas -scanner-prefix-map-paths %swift_src_root /^src -scanner-prefix-map-paths %t /^tmp -scanner-output-dir %t -auto-bridging-header-chaining
 
 // RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps.json deps casFSRootID > %t/deps.fs.casid
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-include-tree-list @%t/deps.fs.casid | %FileCheck %s -check-prefix DEPS-FS
diff --git a/test/CAS/opt-record.swift b/test/CAS/opt-record.swift
new file mode 100644
index 0000000000000..3625d6c7b9406
--- /dev/null
+++ b/test/CAS/opt-record.swift
@@ -0,0 +1,46 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %s -o %t/deps.json -swift-version 5 -cache-compile-job -cas-path %t/cas
+
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps.json > %t/map.json
+// RUN: llvm-cas --cas %t/cas --make-blob --data %t/map.json > %t/map.casid
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json Test > %t/MyApp.cmd
+
+// RUN: %target-swift-frontend -c -cache-compile-job -cas-path %t/cas -O \
+// RUN:   -save-optimization-record -save-optimization-record-path %t/record.yaml \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
+// RUN:   @%t/MyApp.cmd %s -o %t/test.o -Rcache-compile-job 2>&1 | %FileCheck %s --check-prefix=CACHE-MISS
+
+// RUN: %target-swift-frontend -c -cache-compile-job -cas-path %t/cas -O \
+// RUN:   -save-optimization-record -save-optimization-record-path %t/record-1.yaml \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
+// RUN:   @%t/MyApp.cmd %s -o %t/test.o -Rcache-compile-job 2>&1 | %FileCheck %s --check-prefix=CACHE-HIT
+
+// RUN: %FileCheck %s --check-prefix=YAML --input-file=%t/record.yaml
+
+/// FIXME: Remarks are not produced when cache hit.
+// RUN: not %FileCheck %s --check-prefix=YAML --input-file=%t/record-1.yaml
+
+// CACHE-MISS: remark: cache miss for input
+// CACHE-HIT: remark: replay output file '<cached-diagnostics>': key 'llvmcas://{{.*}}'
+// CACHE-HIT: remark: replay output file '{{.*}}{{/|\\}}test.o': key 'llvmcas://{{.*}}'
+// YAML: ---
+
+var a: Int = 1
+
+func foo() {
+  a = 2
+}
+
+public func bar() {
+  foo()
+}
diff --git a/test/CAS/path_remap.swift b/test/CAS/path_remap.swift
index b8788e918c97b..80c879c80345a 100644
--- a/test/CAS/path_remap.swift
+++ b/test/CAS/path_remap.swift
@@ -4,7 +4,7 @@
 // RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   %t/main.swift -o %t/deps.json -swift-version 5 -cache-compile-job -cas-path %t/cas -I %t/include -sdk %t/sdk \
-// RUN:   -scanner-prefix-map %swift_src_root=/^src -scanner-prefix-map %t=/^tmp -scanner-prefix-map %t/sdk=/^sdk -enable-cross-import-overlays
+// RUN:   -scanner-prefix-map-paths %swift_src_root /^src -scanner-prefix-map-paths %t /^tmp -scanner-prefix-map-paths %t/sdk /^sdk -enable-cross-import-overlays
 
 // RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json A > %t/A.cmd
 // RUN: %swift_frontend_plain @%t/A.cmd
@@ -32,7 +32,7 @@
 // RUN:   -swift-version 5 -disable-implicit-swift-modules \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
-// RUN:   -cache-replay-prefix-map /^src=%swift_src_root -cache-replay-prefix-map /^tmp=%t -cache-replay-prefix-map /^sdk=%t/sdk \
+// RUN:   -cache-replay-prefix-map /^src %swift_src_root -cache-replay-prefix-map /^tmp %t -cache-replay-prefix-map /^sdk %t/sdk \
 // RUN:   /^tmp/main.swift @%t/MyApp.cmd -enable-cross-import-overlays
 
 // RUN: %swift-scan-test -action compute_cache_key_from_index -cas-path %t/cas -input 0 -- \
@@ -41,7 +41,7 @@
 // RUN:   -swift-version 5 -disable-implicit-swift-modules \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
-// RUN:   -cache-replay-prefix-map /^src=%swift_src_root -cache-replay-prefix-map /^tmp=%t -cache-replay-prefix-map /^sdk=%t/sdk \
+// RUN:   -cache-replay-prefix-map /^src %swift_src_root -cache-replay-prefix-map /^tmp %t -cache-replay-prefix-map /^sdk %t/sdk \
 // RUN:   /^tmp/main.swift @%t/MyApp.cmd -enable-cross-import-overlays > %t/key.casid
 
 // RUN: %swift-scan-test -action replay_result -cas-path %t/cas -id @%t/key.casid -- \
@@ -50,7 +50,7 @@
 // RUN:   -swift-version 5 -disable-implicit-swift-modules \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
-// RUN:   -cache-replay-prefix-map /^src=%swift_src_root -cache-replay-prefix-map /^tmp=%t -cache-replay-prefix-map /^sdk=%t/sdk \
+// RUN:   -cache-replay-prefix-map /^src %swift_src_root -cache-replay-prefix-map /^tmp %t -cache-replay-prefix-map /^sdk %t/sdk \
 // RUN:   /^tmp/main.swift @%t/MyApp.cmd -enable-cross-import-overlays
 
 //--- main.swift
diff --git a/test/CAS/plugin_cas.swift b/test/CAS/plugin_cas.swift
index 735fc133d5b9c..476e97eb652c4 100644
--- a/test/CAS/plugin_cas.swift
+++ b/test/CAS/plugin_cas.swift
@@ -62,7 +62,6 @@ import SubE
 // CHECK-SAME: Bridging.h
 
 // CHECK-NEXT: "sourceFiles":
-// CHECK-NEXT: ChainedBridgingHeader.h
 // CHECK-NEXT: Bridging.h
 // CHECK-NEXT: BridgingOther.h
 
diff --git a/test/CAS/reproducer.swift b/test/CAS/reproducer.swift
new file mode 100644
index 0000000000000..fda6882ba81ab
--- /dev/null
+++ b/test/CAS/reproducer.swift
@@ -0,0 +1,85 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -O -module-cache-path %t/clang-module-cache \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -import-objc-header %t/Bridging.h -scanner-output-dir %t -auto-bridging-header-chaining -scanner-debug-write-output \
+// RUN:   %t/test.swift %t/foo.swift -I %t/include -o %t/deps.json -cache-compile-job -cas-path %t/cas
+
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:Dummy > %t/dummy.cmd
+// RUN: %swift_frontend_plain @%t/dummy.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json Simple > %t/simple.cmd
+// RUN: %swift_frontend_plain @%t/simple.cmd
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json bridgingHeader > %t/header.cmd
+// RUN: %target-swift-frontend @%t/header.cmd %t/Bridging.h -disable-implicit-swift-modules -O -o %t/bridging.pch
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
+// RUN:   %target-swift-frontend @%t/header.cmd %t/Bridging.h -disable-implicit-swift-modules -O -o %t/bridging.pch > %t/keys.json
+// RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json > %t/key
+
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps.json > %t/map.json
+// RUN: llvm-cas --cas %t/cas --make-blob --data %t/map.json > %t/map.casid
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json Test > %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-string-processing-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-concurrency-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-swift-modules\"" >> %t/MyApp.cmd
+// RUN: echo "\"-import-objc-header\"" >> %t/MyApp.cmd
+// RUN: echo "\"%t/Bridging.h\"" >> %t/MyApp.cmd
+// RUN: echo "\"-import-pch\"" >> %t/MyApp.cmd
+// RUN: echo "\"%t/bridging.pch\"" >> %t/MyApp.cmd
+// RUN: echo "\"-bridging-header-pch-key\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/key\"" >> %t/MyApp.cmd
+// RUN: echo "\"-explicit-swift-module-map-file\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/map.casid\"" >> %t/MyApp.cmd
+
+// RUN: %target-swift-frontend %t/test.swift %t/foo.swift -O -emit-module -emit-module-path %t/Test.swiftmodule -c \
+// RUN:  -module-name Test -o %t/test.o -cache-compile-job -cas-path %t/cas @%t/MyApp.cmd -gen-reproducer -gen-reproducer-dir %t/crash
+
+// RUN: %FileCheck %s --input-file=%t/crash/reproduce.sh
+// CHECK: -cache-compile-job
+// CHECK-NOT: -gen-reproducer
+
+/// Delete some inputs from original compilation and run the reproducer.
+// RUN: rm -rf %t/include
+// RUN: %swift_frontend_plain @%t/crash/reproduce.sh
+
+/// Also test module jobs.
+// RUN: %swift_frontend_plain @%t/dummy.cmd -gen-reproducer -gen-reproducer-dir %t/crash-2
+// RUN: %FileCheck %s --input-file=%t/crash-2/reproduce.sh
+// RUN: %swift_frontend_plain @%t/crash-2/reproduce.sh
+// RUN: %swift_frontend_plain @%t/simple.cmd -gen-reproducer -gen-reproducer-dir %t/crash-3
+// RUN: %FileCheck %s --input-file=%t/crash-3/reproduce.sh
+// RUN: %swift_frontend_plain @%t/crash-3/reproduce.sh
+
+//--- test.swift
+import Dummy
+import Simple
+public func testFunc() {
+  foo()
+  bridge()
+  simple()
+}
+
+//--- foo.swift
+public func foo() {}
+
+//--- Bridging.h
+void bridge(void);
+
+//--- include/module.modulemap
+module Dummy {
+ umbrella header "Dummy.h"
+}
+
+//--- include/Dummy.h
+void dummy(void);
+
+//--- include/Simple.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name Simple -O -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import
+import Swift
+import Dummy
+public func simple() { }
diff --git a/test/CAS/simlink_inputs.swift b/test/CAS/simlink_inputs.swift
index b6892a74e3774..7e944f6c4371c 100644
--- a/test/CAS/simlink_inputs.swift
+++ b/test/CAS/simlink_inputs.swift
@@ -26,7 +26,7 @@
 /// Test the same build but remapping the path.
 // RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
-// RUN:   -scanner-prefix-map %swift_src_root=/^src -scanner-prefix-map %t/src=/^tmp -scanner-prefix-map %t/sdk=/^sdk \
+// RUN:   -scanner-prefix-map-paths %swift_src_root /^src -scanner-prefix-map-paths %t/src /^tmp -scanner-prefix-map-paths %t/sdk /^sdk \
 // RUN:   %t/src/main.swift -o %t/deps-1.json -swift-version 5 -cache-compile-job -cas-path %t/cas -I %t/src/include
 
 // RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps-1.json clang:A > %t/A-1.cmd
@@ -42,7 +42,7 @@
 // RUN:   -swift-version 5 -disable-implicit-swift-modules \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   -module-name Test -explicit-swift-module-map-file @%t/map-1.casid \
-// RUN:   -cache-replay-prefix-map /^src=%swift_src_root -cache-replay-prefix-map /^tmp=%t/src -cache-replay-prefix-map /^sdk=%t/sdk \
+// RUN:   -cache-replay-prefix-map /^src %swift_src_root -cache-replay-prefix-map /^tmp %t/src -cache-replay-prefix-map /^sdk %t/sdk \
 // RUN:   /^tmp/main.swift @%t/MyApp-1.cmd
 
 //--- private/main.swift
diff --git a/test/CAS/uncached-casfs.swift b/test/CAS/uncached-casfs.swift
new file mode 100644
index 0000000000000..92620e7ef96eb
--- /dev/null
+++ b/test/CAS/uncached-casfs.swift
@@ -0,0 +1,79 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -O -module-cache-path %t/clang-module-cache \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -import-objc-header %t/base/Bridging.h -scanner-output-dir %t -auto-bridging-header-chaining -scanner-debug-write-output \
+// RUN:   %t/base/test.swift %t/base/foo.swift -I %t/include -o %t/deps.json -cache-compile-job -cas-path %t/cas
+
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:Dummy > %t/dummy.cmd
+// RUN: %swift_frontend_plain @%t/dummy.cmd
+
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps.json > %t/map.json
+// RUN: llvm-cas --cas %t/cas --make-blob --data %t/map.json > %t/map.casid
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json bridgingHeader > %t/header.cmd
+// RUN: %target-swift-frontend @%t/header.cmd %t/base/Bridging.h -disable-implicit-swift-modules -O -o %t/bridging.pch
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
+// RUN:   %target-swift-frontend @%t/header.cmd %t/base/Bridging.h -disable-implicit-swift-modules -O -o %t/bridging.pch > %t/keys.json
+// RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json > %t/key
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json Test > %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-string-processing-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-concurrency-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-swift-modules\"" >> %t/MyApp.cmd
+// RUN: echo "\"-import-objc-header\"" >> %t/MyApp.cmd
+// RUN: echo "\"%t/base/Bridging.h\"" >> %t/MyApp.cmd
+// RUN: echo "\"-import-pch\"" >> %t/MyApp.cmd
+// RUN: echo "\"%t/bridging.pch\"" >> %t/MyApp.cmd
+// RUN: echo "\"-bridging-header-pch-key\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/key\"" >> %t/MyApp.cmd
+// RUN: echo "\"-explicit-swift-module-map-file\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/map.casid\"" >> %t/MyApp.cmd
+
+// RUN: sed -e "s@VFS_DIR@%{/t:regex_replacement}/base@g" -e "s@EXTERNAL_DIR@%{/t:regex_replacement}/modified@g" %t/base.yaml > %t/overlay.yaml
+
+// RUN: %target-swift-frontend %t/base/test.swift %t/base/foo.swift -O -emit-module -emit-module-path %t/Test.swiftmodule -c \
+// RUN:  -module-name Test -o %t/test.o -cas-path %t/cas @%t/MyApp.cmd -vfsoverlay %t/overlay.yaml -module-import-from-cas
+
+
+//--- base/test.swift
+import Dummy
+public func testFunc() {
+  non_existing_func()
+}
+
+//--- base/foo.swift
+public func foo() {}
+
+//--- modified/test.swift
+import Dummy
+public func testFunc() {
+  dummy()
+  bridge()
+}
+
+//--- base/Bridging.h
+void bridge(void);
+
+//--- include/module.modulemap
+module Dummy {
+ umbrella header "Dummy.h"
+}
+
+//--- include/Dummy.h
+void dummy(void);
+
+//--- base.yaml
+{
+  version: 0,
+  roots: [
+    {
+      type: "directory-remap",
+      name: "VFS_DIR",
+      external-contents: "EXTERNAL_DIR"
+    }
+  ]
+}
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 503a8748ae64b..98fdb1942b5fe 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -12,11 +12,7 @@ function(swift_configure_lit_site_cfg source_path destination_path installed_nam
   string(REPLACE ${CMAKE_CFG_INTDIR} ${SWIFT_BUILD_MODE} LLVM_TOOLS_DIR ${LLVM_TOOLS_BINARY_DIR})
   string(REPLACE ${CMAKE_CFG_INTDIR} ${SWIFT_BUILD_MODE} LLVM_LIBS_DIR  ${LLVM_LIBRARY_DIR})
 
-  if (XCODE)
-    string(REPLACE ${CMAKE_CFG_INTDIR} Debug LIT_SWIFTLIB_DIR ${SWIFTLIB_DIR})
-  else ()
-    set(LIT_SWIFTLIB_DIR ${SWIFTLIB_DIR})
-  endif ()
+  set(LIT_SWIFTLIB_DIR ${SWIFTLIB_DIR})
 
   configure_file("${source_path}" "${destination_path}" @ONLY)
 
@@ -114,8 +110,6 @@ function(get_test_dependencies SDK result_var_name)
 
   if(NOT SWIFT_BUILT_STANDALONE)
     list(APPEND deps_binaries
-      arcmt-test
-      c-arcmt-test
       c-index-test
       CASPluginTest
       clang
@@ -141,7 +135,8 @@ function(get_test_dependencies SDK result_var_name)
       llvm-strings
       llvm-readtapi
       not
-      split-file)
+      split-file
+      yaml2obj)
   endif()
 
   if(("${SDK}" STREQUAL "IOS") OR
@@ -182,51 +177,129 @@ set(SWIFT_LIT_ARGS "" CACHE STRING "Arguments to pass to lit")
 
 set(SWIFT_LIT_ENVIRONMENT "" CACHE STRING "Environment to use for lit invocations")
 
-if(NOT SWIFT_INCLUDE_TOOLS)
-  if(SWIFT_RUN_TESTS_WITH_HOST_COMPILER)
-    precondition(CMAKE_Swift_COMPILER MESSAGE "Can only run tests if a Swift compiler is specified")
-    get_filename_component(SWIFT_COMPILER_DIR "${CMAKE_Swift_COMPILER}" DIRECTORY)
-    precondition(SWIFT_COMPILER_DIR)
-    # We assume that we are building against a toolchain where all tools are
-    # next to swiftc.
-    list(APPEND SWIFT_LIT_ARGS
-      "--path=${SWIFT_COMPILER_DIR}")
-  else()
-    list(APPEND SWIFT_LIT_ARGS
-      "--path=${SWIFT_NATIVE_LLVM_TOOLS_PATH}"
-      "--param" "swift_native_llvm_tools_path=${SWIFT_NATIVE_LLVM_TOOLS_PATH}"
-      "--path=${SWIFT_NATIVE_CLANG_TOOLS_PATH}"
-      "--param" "swift_native_clang_tools_path=${SWIFT_NATIVE_CLANG_TOOLS_PATH}"
-      "--path=${SWIFT_NATIVE_SWIFT_TOOLS_PATH}"
-      "--param" "swift_native_swift_tools_path=${SWIFT_NATIVE_SWIFT_TOOLS_PATH}"
-      )
-  endif()
-  if(SWIFT_BUILD_STDLIB)
-    # If building only static stdlib, use `swift_static` resources directory.
-    if(NOT SWIFT_BUILD_DYNAMIC_STDLIB AND SWIFT_BUILD_STATIC_STDLIB)
-      list(APPEND SWIFT_LIT_ARGS
-           "--param" "test_resource_dir=${SWIFTSTATICLIB_DIR}")
+option(SWIFT_TEST_USE_LEAKS "Run Swift stdlib tests under leaks" FALSE)
+
+function(setup_lit_args ARGS_VAR_OUT tested_sdk test_results_dir resource_dir_override)
+  set(swift_lit_args_result)
+
+  if(NOT SWIFT_INCLUDE_TOOLS)
+    if(SWIFT_RUN_TESTS_WITH_HOST_COMPILER)
+      precondition(CMAKE_Swift_COMPILER MESSAGE "Can only run tests if a Swift compiler is specified")
+      get_filename_component(SWIFT_COMPILER_DIR "${CMAKE_Swift_COMPILER}" DIRECTORY)
+      precondition(SWIFT_COMPILER_DIR)
+      # We assume that we are building against a toolchain where all tools are
+      # next to swiftc.
+      list(APPEND swift_lit_args_result
+        "--path=${SWIFT_COMPILER_DIR}")
     else()
-      list(APPEND SWIFT_LIT_ARGS
-           "--param" "test_resource_dir=${SWIFTLIB_DIR}")
+      list(APPEND swift_lit_args_result
+        "--path=${SWIFT_NATIVE_LLVM_TOOLS_PATH}"
+        "--param" "swift_native_llvm_tools_path=${SWIFT_NATIVE_LLVM_TOOLS_PATH}"
+        "--path=${SWIFT_NATIVE_CLANG_TOOLS_PATH}"
+        "--param" "swift_native_clang_tools_path=${SWIFT_NATIVE_CLANG_TOOLS_PATH}"
+        "--path=${SWIFT_NATIVE_SWIFT_TOOLS_PATH}"
+        "--param" "swift_native_swift_tools_path=${SWIFT_NATIVE_SWIFT_TOOLS_PATH}"
+        )
+    endif()
+    if(SWIFT_BUILD_STDLIB)
+      if(resource_dir_override)
+        list(APPEND swift_lit_args_result
+             "--param" "test_resource_dir=${resource_dir_override}")
+      # If building only static stdlib, use `swift_static` resources directory.
+      elseif(NOT SWIFT_BUILD_DYNAMIC_STDLIB AND SWIFT_BUILD_STATIC_STDLIB)
+        list(APPEND swift_lit_args_result
+             "--param" "test_resource_dir=${SWIFTSTATICLIB_DIR}")
+      else()
+        list(APPEND swift_lit_args_result
+             "--param" "test_resource_dir=${SWIFTLIB_DIR}")
+      endif()
     endif()
   endif()
-endif()
 
-option(SWIFT_TEST_USE_LEAKS "Run Swift stdlib tests under leaks" FALSE)
-if (SWIFT_TEST_USE_LEAKS)
-  list(APPEND SWIFT_LIT_ARGS "--param" "leaks-all")
-endif()
+  if (SWIFT_TEST_USE_LEAKS)
+    list(APPEND swift_lit_args_result "--param" "leaks-all")
+  endif()
 
-if (SWIFT_ENABLE_ARRAY_COW_CHECKS)
-  list(APPEND SWIFT_LIT_ARGS
-       "--param" "array_cow_checks")
-endif()
+  if (SWIFT_ENABLE_ARRAY_COW_CHECKS)
+    list(APPEND swift_lit_args_result
+         "--param" "array_cow_checks")
+  endif()
 
-if(NOT CMAKE_CFG_INTDIR STREQUAL ".")
-  list(APPEND SWIFT_LIT_ARGS
-       "--param" "build_mode=${CMAKE_CFG_INTDIR}")
-endif()
+  if(NOT CMAKE_CFG_INTDIR STREQUAL ".")
+    list(APPEND swift_lit_args_result
+         "--param" "build_mode=${CMAKE_CFG_INTDIR}")
+  endif()
+
+  if(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING)
+    list(APPEND swift_lit_args_result "--param" "differentiable_programming")
+  endif()
+
+  if(SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY)
+    list(APPEND swift_lit_args_result "--param" "concurrency")
+  endif()
+
+  if(SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED)
+    list(APPEND swift_lit_args_result "--param" "distributed")
+  endif()
+
+  if(SWIFT_ENABLE_EXPERIMENTAL_STRING_PROCESSING)
+    list(APPEND swift_lit_args_result "--param" "string_processing")
+  endif()
+
+  if(SWIFT_ENABLE_BACKTRACING)
+    list(APPEND swift_lit_args_result "--param" "backtracing")
+  endif()
+
+  if(SWIFT_ENABLE_EXPERIMENTAL_OBSERVATION)
+    list(APPEND swift_lit_args_result "--param" "observation")
+  endif()
+
+  if(SWIFT_ENABLE_SYNCHRONIZATION)
+    list(APPEND swift_lit_args_result "--param" "synchronization")
+  endif()
+
+  if(SWIFT_ENABLE_VOLATILE)
+    list(APPEND swift_lit_args_result "--param" "volatile")
+  endif()
+
+  if(SWIFT_ENABLE_RUNTIME_MODULE)
+    list(APPEND swift_lit_args_result "--param" "runtime_module")
+  endif()
+
+  if(SWIFT_BUILD_REMOTE_MIRROR)
+    list(APPEND swift_lit_args_result "--param" "remote_mirror")
+  endif()
+
+  list(APPEND swift_lit_args_result "--param" "threading=${SWIFT_SDK_${tested_sdk}_THREADING_PACKAGE}")
+
+  # Enable on-crash backtracing if supported
+  if(("${tested_sdk}" STREQUAL "OSX" OR "${tested_sdk}" STREQUAL "LINUX")
+      AND NOT SWIFT_ASAN_BUILD)
+    list(APPEND swift_lit_args_result "--param" "backtrace_on_crash")
+  endif()
+
+  execute_process(COMMAND
+      $<TARGET_FILE:Python3::Interpreter> "-c" "import psutil"
+      RESULT_VARIABLE python_psutil_status
+      TIMEOUT 1 # second
+      ERROR_QUIET)
+  if(NOT python_psutil_status)
+    list(APPEND swift_lit_args_result "--timeout=3000") # 50 minutes
+  endif()
+
+  list(APPEND swift_lit_args_result "--xunit-xml-output=${test_results_dir}/lit-tests.xml")
+
+  if(NOT SWIFT_BUILD_STDLIB AND NOT SWIFT_PATH_TO_EXTERNAL_STDLIB_BUILD)
+    list(APPEND swift_lit_args_result
+        "--param" "test_sdk_overlay_dir=${SWIFTLIB_DIR}/${SWIFT_SDK_${tested_sdk}_LIB_SUBDIR}")
+  endif()
+
+
+  set(swift_lit_args_result "${swift_lit_args_result} ${SWIFT_LIT_ARGS} ${LLVM_LIT_ARGS}")
+  separate_arguments(swift_lit_args_result)
+
+  set(${ARGS_VAR_OUT} ${swift_lit_args_result} PARENT_SCOPE)
+endfunction()
 
 if (LLVM_USE_SANITIZER STREQUAL "Address")
   set(SWIFT_ASAN_BUILD TRUE)
@@ -276,6 +349,7 @@ set(profdata_merge_worker
 
 set(TEST_MODES
     optimize_none optimize optimize_unchecked optimize_size
+    optimize_none_with_opaque_values
     optimize_none_with_implicit_dynamic
     optimize_with_implicit_dynamic
     only_executable only_non_executable
@@ -310,6 +384,7 @@ foreach(SDK ${SWIFT_SDKS})
       get_swift_test_variant_suffix(VARIANT_SUFFIX "${SDK}" "${ARCH}" "${BUILD_FLAVOR}")
       get_swift_test_variant_suffix(DEFAULT_OSX_VARIANT_SUFFIX "${SDK}" "${ARCH}" "default")
       get_swift_test_versioned_target_triple(VARIANT_TRIPLE "${SDK}" "${ARCH}" "${SWIFT_SDK_${SDK}_DEPLOYMENT_VERSION}" "${BUILD_FLAVOR}")
+      set(VARIANT_MODULE_TRIPLE "${SWIFT_SDK_${SDK}_ARCH_${ARCH}_MODULE}")
 
       # A directory where to put the xUnit-style XML test results.
       set(SWIFT_TEST_RESULTS_DIR
@@ -332,6 +407,14 @@ foreach(SDK ${SWIFT_SDKS})
       set(VARIANT_EXTERNAL_EMBEDDED_PLATFORM FALSE)
       set(VARIANT_EXTERNAL_EMBEDDED_DEVICE)
 
+      # Reset these values for WASI, as Embedded Swift for WASI requires separate lit configs.
+      set(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB_old ${SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB})
+      set(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB_CROSS_COMPILING_old ${SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB_CROSS_COMPILING})
+      if("${SDK}" STREQUAL "WASI")
+        set(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB OFF)
+        set(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB_CROSS_COMPILING OFF)
+      endif()
+
       swift_configure_lit_site_cfg(
           "${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in"
           "${test_bin_dir}/lit.site.cfg"
@@ -354,6 +437,10 @@ foreach(SDK ${SWIFT_SDKS})
           "${test_bin_dir}/lit.swift-features.cfg"
           "${validation_test_bin_dir}/lit.swift-features.cfg")
 
+      # Restore old values in case they were reset for WASI tests lit configs.
+      set(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB ${SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB_old})
+      set(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB_CROSS_COMPILING ${SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB_CROSS_COMPILING_old})
+
       set(test_dependencies)
       get_test_dependencies("${SDK}" test_dependencies)
 
@@ -431,73 +518,6 @@ foreach(SDK ${SWIFT_SDKS})
           COMMENT "Uploading stdlib")
 
       foreach(test_mode ${TEST_MODES})
-        set(LIT_ARGS "${SWIFT_LIT_ARGS} ${LLVM_LIT_ARGS}")
-        separate_arguments(LIT_ARGS)
-
-        if(NOT SWIFT_BUILD_STDLIB AND NOT SWIFT_PATH_TO_EXTERNAL_STDLIB_BUILD)
-          list(APPEND LIT_ARGS
-              "--param" "test_sdk_overlay_dir=${SWIFTLIB_DIR}/${SWIFT_SDK_${SDK}_LIB_SUBDIR}")
-        endif()
-
-        execute_process(COMMAND
-            $<TARGET_FILE:Python3::Interpreter> "-c" "import psutil"
-            RESULT_VARIABLE python_psutil_status
-            TIMEOUT 1 # second
-            ERROR_QUIET)
-        if(NOT python_psutil_status)
-          list(APPEND LIT_ARGS "--timeout=3000") # 50 minutes
-        endif()
-
-        list(APPEND LIT_ARGS "--xunit-xml-output=${SWIFT_TEST_RESULTS_DIR}/lit-tests.xml")
-
-        if(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING)
-          list(APPEND LIT_ARGS "--param" "differentiable_programming")
-        endif()
-
-        if(SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY)
-          list(APPEND LIT_ARGS "--param" "concurrency")
-        endif()
-
-        if(SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED)
-          list(APPEND LIT_ARGS "--param" "distributed")
-        endif()
-
-        if(SWIFT_ENABLE_EXPERIMENTAL_STRING_PROCESSING)
-          list(APPEND LIT_ARGS "--param" "string_processing")
-        endif()
-
-        if(SWIFT_ENABLE_BACKTRACING)
-          list(APPEND LIT_ARGS "--param" "backtracing")
-        endif()
-
-        if(SWIFT_ENABLE_EXPERIMENTAL_OBSERVATION)
-          list(APPEND LIT_ARGS "--param" "observation")
-        endif()
-
-        if(SWIFT_ENABLE_SYNCHRONIZATION)
-          list(APPEND LIT_ARGS "--param" "synchronization")
-        endif()
-
-        if(SWIFT_ENABLE_VOLATILE)
-          list(APPEND LIT_ARGS "--param" "volatile")
-        endif()
-
-        if(SWIFT_ENABLE_RUNTIME_MODULE)
-          list(APPEND LIT_ARGS "--param" "runtime_module")
-        endif()
-
-        if(SWIFT_BUILD_REMOTE_MIRROR)
-          list(APPEND LIT_ARGS "--param" "remote_mirror")
-        endif()
-
-        list(APPEND LIT_ARGS "--param" "threading=${SWIFT_SDK_${SDK}_THREADING_PACKAGE}")
-
-        # Enable on-crash backtracing if supported
-        if(("${SDK}" STREQUAL "OSX" OR "${SDK}" STREQUAL "LINUX")
-            AND NOT SWIFT_ASAN_BUILD)
-          list(APPEND LIT_ARGS "--param" "backtrace_on_crash")
-        endif()
-
         foreach(test_subset ${TEST_SUBSETS})
           set(directories)
           set(dependencies ${test_dependencies})
@@ -537,6 +557,8 @@ foreach(SDK ${SWIFT_SDKS})
             set(maybe_command_upload_stdlib ${command_upload_stdlib})
           endif()
 
+          setup_lit_args(final_lit_args "${SDK}" "${SWIFT_TEST_RESULTS_DIR}" OFF)
+
           set(test_target_name
               "check-swift${test_subset_target_suffix}${test_mode_target_suffix}${VARIANT_SUFFIX}")
           add_custom_target("${test_target_name}"
@@ -546,7 +568,7 @@ foreach(SDK ${SWIFT_SDKS})
               COMMAND
                 ${CMAKE_COMMAND} -E env ${SWIFT_LIT_ENVIRONMENT}
                 $<TARGET_FILE:Python3::Interpreter> "${LIT}"
-                ${LIT_ARGS}
+                ${final_lit_args}
                 "--param" "swift_test_subset=${test_subset}"
                 "--param" "swift_test_mode=${test_mode}"
                 ${directories}
@@ -566,7 +588,7 @@ foreach(SDK ${SWIFT_SDKS})
               COMMAND
                 ${CMAKE_COMMAND} -E env ${SWIFT_LIT_ENVIRONMENT}
                 $<TARGET_FILE:Python3::Interpreter> "${LIT}"
-                ${LIT_ARGS}
+                ${final_lit_args}
                 "--param" "swift_test_subset=${test_subset}"
                 "--param" "swift_test_mode=${test_mode}"
                 ${SWIFT_LIT_TEST_PATHS}
@@ -580,6 +602,43 @@ foreach(SDK ${SWIFT_SDKS})
               PROPERTY FOLDER "Tests/check-swift")
         endforeach()
       endforeach()
+
+      if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB_CROSS_COMPILING AND (${ARCH} STREQUAL "wasm32"))
+        set(test_mode "optimize_none")
+        set(test_subset "primary")
+        set(VARIANT_SUFFIX "-embedded-wasi")
+        set(VARIANT_TRIPLE "wasm32-unknown-wasip1")
+        set(test_bin_dir "${CMAKE_CURRENT_BINARY_DIR}${VARIANT_SUFFIX}/embedded")
+        set(VARIANT_EXTERNAL_EMBEDDED_PLATFORM FALSE)
+        set(VARIANT_EXTERNAL_EMBEDDED_DEVICE)
+        set(SWIFT_TEST_RESULTS_DIR "${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/swift-test-results/${VARIANT_TRIPLE}")
+        swift_configure_lit_site_cfg(
+            "${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in"
+            "${CMAKE_CURRENT_BINARY_DIR}${VARIANT_SUFFIX}/lit.site.cfg"
+            "test${VARIANT_SUFFIX}.lit.site.cfg")
+        swift_generate_lit_swift_features_cfg("${CMAKE_CURRENT_BINARY_DIR}${VARIANT_SUFFIX}/lit.swift-features.cfg")
+
+        set(test_target_name "check-swift${VARIANT_SUFFIX}")
+        set(directories "${test_bin_dir}")
+
+        set(embedded_wasm_lit_args)
+        setup_lit_args(embedded_wasm_lit_args "${SDK}" "${SWIFT_TEST_RESULTS_DIR}" "${SWIFTLIB_DIR}")
+
+        add_custom_target("${test_target_name}"
+            ${maybe_command_upload_stdlib}
+            ${command_upload_swift_reflection_test}
+            ${command_clean_test_results_dir}
+            COMMAND
+              ${CMAKE_COMMAND} -E env ${SWIFT_LIT_ENVIRONMENT}
+              $<TARGET_FILE:Python3::Interpreter> "${LIT}"
+              ${embedded_wasm_lit_args}
+              "--param" "swift_test_subset=${test_subset}"
+              "--param" "swift_test_mode=${test_mode}"
+              ${directories}
+            DEPENDS ${dependencies}
+            COMMENT "Running ${test_subset} Swift tests for ${VARIANT_TRIPLE}"
+            USES_TERMINAL)
+        endif()
     endforeach()
   endforeach()
 endforeach()
diff --git a/test/Casting/CastTraps.swift.gyb b/test/Casting/CastTraps.swift.gyb
index 3f7af893ef780..8fe1006c64685 100644
--- a/test/Casting/CastTraps.swift.gyb
+++ b/test/Casting/CastTraps.swift.gyb
@@ -142,4 +142,35 @@ CastTrapsTestSuite.test("Unexpected Obj-C null")
 }
 #endif
 
+class Base {}
+final class Derived: Base {}
+final class Other: Base {}
+
+@inline(never)
+func getDerived(_ v: Base) -> Derived {
+  return v as! Derived
+}
+
+@inline(never)
+func getDerivedFromOptional(_ v: Base?) -> Derived {
+  return v as! Derived
+}
+
+CastTrapsTestSuite.test("unconditinal fast class cast") {
+  let c = Other()
+  expectCrashLater()
+  _ = getDerived(c)
+}
+
+CastTrapsTestSuite.test("unconditinal optional fast class cast") {
+  let c = Other()
+  expectCrashLater()
+  _ = getDerivedFromOptional(c)
+}
+
+CastTrapsTestSuite.test("unconditinal optional nil fast class cast") {
+  expectCrashLater()
+  _ = getDerivedFromOptional(nil)
+}
+
 runAllTests()
diff --git a/test/Casting/ParameterizedExistentials.swift b/test/Casting/ParameterizedExistentials.swift
index ea893d7c02912..c6fd92d30c49f 100644
--- a/test/Casting/ParameterizedExistentials.swift
+++ b/test/Casting/ParameterizedExistentials.swift
@@ -46,7 +46,10 @@ struct GenericHolder<T>: Holder {
   init(value: T) { self.value = value}
 }
 
-protocol PairType<T, U> {
+protocol PairType<
+  T,
+  U,
+> {
   associatedtype T
   associatedtype U
 
diff --git a/test/Casting/fast_class_casts.swift b/test/Casting/fast_class_casts.swift
index 54a309a868c8b..c0d11dddad7d7 100644
--- a/test/Casting/fast_class_casts.swift
+++ b/test/Casting/fast_class_casts.swift
@@ -56,6 +56,15 @@ func unconditionalCastToFinal(_ b: Classes.Base) -> Classes.Final {
   return b as! Classes.Final
 }
 
+// CHECK-LABEL: define {{.*}} @"$s4Main32unconditionalOptionalCastToFinaly7Classes0F0CAC4BaseCSgF"
+// CHECK-NOT:     call {{.*}}@object_getClass
+// CHECK-NOT:     @swift_dynamicCastClass
+// CHECK:       }
+@inline(never)
+func unconditionalOptionalCastToFinal(_ b: Classes.Base?) -> Classes.Final {
+  return b as! Classes.Final
+}
+
 // CHECK-LABEL: define {{.*}} @"$s4Main20castToResilientFinaly0D7Classes0E0CSgAC4BaseCF"
 // CHECK:         @swift_dynamicCastClass
 // CHECK:       }
@@ -132,7 +141,9 @@ func test() {
   // CHECK-OUTPUT: Optional(Classes.Final)
   print(castToFinal(Classes.Final()) as Any)
   // CHECK-OUTPUT: Classes.Final
-  print(unconditionalCastToFinal(Classes.Final()) as Any)
+  print(unconditionalCastToFinal(Classes.Final()))
+  // CHECK-OUTPUT: Classes.Final
+  print(unconditionalOptionalCastToFinal(Classes.Final()))
 
   // CHECK-OUTPUT: nil
   print(castToResilientFinal(ResilientClasses.Base()) as Any)
diff --git a/test/CircularReferences/global_typealias.swift b/test/CircularReferences/global_typealias.swift
index 1982ea1dfc2a3..049a345b2cd6a 100644
--- a/test/CircularReferences/global_typealias.swift
+++ b/test/CircularReferences/global_typealias.swift
@@ -1,6 +1,6 @@
 // RUN: %target-typecheck-verify-swift
 
-typealias A = B // expected-error {{type alias 'A' references itself}} expected-note {{while resolving type 'B'}} expected-note {{through reference here}}
-typealias C = D // expected-note {{through reference here}} expected-note {{while resolving type 'D'}} expected-note {{through reference here}}
-typealias D = (A, Int) // expected-note {{through reference here}} expected-note {{while resolving type '(A, Int)'}} expected-note {{through reference here}}
-typealias B = C // expected-note {{through reference here}} expected-note {{while resolving type 'C'}} expected-note {{through reference here}}
+typealias A = B // expected-error {{type alias 'A' references itself}} expected-note {{while resolving type 'B'}}
+typealias C = D // expected-note {{through reference here}} expected-note {{while resolving type 'D'}}
+typealias D = (A, Int) // expected-note {{through reference here}} expected-note {{while resolving type '(A, Int)'}}
+typealias B = C // expected-note {{through reference here}} expected-note {{while resolving type 'C'}}
diff --git a/test/ClangImporter/AppKit_test.swift b/test/ClangImporter/AppKit_test.swift
index 00588146544fa..a8d1c9ac47389 100644
--- a/test/ClangImporter/AppKit_test.swift
+++ b/test/ClangImporter/AppKit_test.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift %clang-importer-sdk
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated %clang-importer-sdk
 
 // REQUIRES: OS=macosx
 
diff --git a/test/ClangImporter/CoreGraphics_test.swift b/test/ClangImporter/CoreGraphics_test.swift
index 7ee411b724c62..d64691be97ce9 100644
--- a/test/ClangImporter/CoreGraphics_test.swift
+++ b/test/ClangImporter/CoreGraphics_test.swift
@@ -25,7 +25,7 @@ public func testEnums(_ model: CGColorSpaceModel) -> Int {
 
      default: return -1
   }
-// CHECK:   [[GEP:%.+]] = getelementptr inbounds [8 x i64], ptr [[SWITCHTABLE]], i64 0, i64 %{{.*}}
+// CHECK:   [[GEP:%.+]] = getelementptr inbounds{{.*}} [8 x i64], ptr [[SWITCHTABLE]], i64 0, i64 %{{.*}}
 // CHECK:   [[LOAD:%.+]] = load i64, ptr [[GEP]], align 8
 // CHECK:   [[PHI:%.*]] = phi i64 [ [[LOAD]], %{{.*}} ], [ -1, %{{.*}} ]
 // CHECK:   ret i64 [[PHI]] 
@@ -105,9 +105,7 @@ public func testRenames(transform: CGAffineTransform, context: CGContext,
   blackHole(point.applying(transform))
   var rect = rect.applying(transform)
   blackHole(size.applying(transform))
-// CHECK:   %{{.*}} = {{(tail )?}}call { double, double } @CGPointApplyAffineTransform(double %{{.*}}, double %{{.*}}, ptr {{.*}})
 // CHECK:   call void @CGRectApplyAffineTransform(ptr {{.*}}, ptr {{.*}}, ptr {{.*}})
-// CHECK:   %{{.*}} = {{(tail )?}}call { double, double } @CGSizeApplyAffineTransform(double %{{.*}}, double %{{.*}}, ptr {{.*}})
 
   context.concatenate(transform)
   context.rotate(by: CGFloat.pi)
diff --git a/test/ClangImporter/Darwin_sdk_test.swift b/test/ClangImporter/Darwin_sdk_test.swift
index d77a28b291bd9..109af3d0707ea 100644
--- a/test/ClangImporter/Darwin_sdk_test.swift
+++ b/test/ClangImporter/Darwin_sdk_test.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck %s -verify
+// RUN: %target-swift-frontend -typecheck %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/Inputs/availability_custom_domains_other.swift b/test/ClangImporter/Inputs/availability_custom_domains_other.swift
index f51a436531000..b4ff807e01264 100644
--- a/test/ClangImporter/Inputs/availability_custom_domains_other.swift
+++ b/test/ClangImporter/Inputs/availability_custom_domains_other.swift
@@ -1,11 +1,34 @@
 import Seas
 
-@available(Arctic) // expected-warning {{unrecognized platform name 'Arctic'}}
+@available(Arctic) // expected-error {{unrecognized platform name 'Arctic'}}
 func availableInArctic() { }
 
 @available(Mediterranean)
 func availableInMediterranean() { }
 
-func testOtherClangDecls() {
+func testOtherClangDecls() { // expected-note {{add '@available' attribute to enclosing global function}}
   available_in_baltic() // expected-error {{'available_in_baltic()' is only available in Baltic}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  available_in_bering() // ok, Bering is always available
+  unavailable_in_bering() // expected-error {{'unavailable_in_bering()' is unavailable}}
+}
+
+@available(Baltic)
+func availableInBalticOther() {
+  available_in_baltic()
+  available_in_bering() // ok, Bering is always available
+  unavailable_in_bering() // expected-error {{'unavailable_in_bering()' is unavailable}}
+}
+
+@available(Bering)
+func availableInBering() { // expected-note {{add '@available' attribute to enclosing global function}}
+  available_in_baltic() // expected-error {{'available_in_baltic()' is only available in Baltic}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  available_in_bering()
+  unavailable_in_bering() // expected-error {{'unavailable_in_bering()' is unavailable}}
+}
+
+@available(Bering, unavailable)
+func unavailableInBering() {
+  unavailable_in_bering()
 }
diff --git a/test/ClangImporter/Inputs/availability_domains_bridging_header.h b/test/ClangImporter/Inputs/availability_domains_bridging_header.h
index c0bccaab7495b..66f8dcf5cb153 100644
--- a/test/ClangImporter/Inputs/availability_domains_bridging_header.h
+++ b/test/ClangImporter/Inputs/availability_domains_bridging_header.h
@@ -1,8 +1,66 @@
-#include <feature-availability.h>
-
-static struct __AvailabilityDomain __BayBridge
-    __attribute__((availability_domain(BayBridge))) = {
-        __AVAILABILITY_DOMAIN_ENABLED, 0};
-static struct __AvailabilityDomain __GoldenGateBridge
-    __attribute__((availability_domain(GoldenGateBridge))) = {
-        __AVAILABILITY_DOMAIN_DISABLED, 0};
+#include <availability_domain.h>
+
+CLANG_DISABLED_AVAILABILITY_DOMAIN(BayBridge);
+CLANG_DISABLED_AVAILABILITY_DOMAIN(GoldenGateBridge);
+
+#define AVAIL 0
+#define UNAVAIL 1
+
+
+#if __OBJC__
+@import Foundation;
+
+__attribute__((availability(domain:BayBridge, AVAIL)))
+@interface BayBridgeAvailable : NSObject
+- (instancetype)init;
+@end
+
+__attribute__((availability(domain:BayBridge, UNAVAIL)))
+@interface BayBridgeUnavailable : NSObject
+- (instancetype)init;
+@end
+
+@interface ImplementMe : NSObject
+- (instancetype)init;
+- (void)availableInBayBridge __attribute__((availability(domain:BayBridge, AVAIL)));
+- (void)unavailableInBayBridge __attribute__((availability(domain:BayBridge, UNAVAIL)));
+
+- (void)availableInGoldenGateBridge __attribute__((availability(domain:GoldenGateBridge, AVAIL)));
+- (void)unavailableInGoldenGateBridge __attribute__((availability(domain:GoldenGateBridge, UNAVAIL)));
+
+@end
+
+__attribute__((availability(domain:BayBridge, AVAIL)))
+@interface ImplementMeBayBridgeAvailable : NSObject
+- (instancetype)init;
+@end
+
+__attribute__((availability(domain:BayBridge, UNAVAIL)))
+@interface ImplementMeBayBridgeUnavailable : NSObject
+- (instancetype)init;
+@end
+
+__attribute__((availability(domain:GoldenGateBridge, AVAIL)))
+@interface ImplementMeGoldenGateBridgeAvailable : NSObject
+- (instancetype)init;
+@end
+
+__attribute__((availability(domain:GoldenGateBridge, AVAIL)))
+@interface ImplementMeGoldenGateBridgeAvailable2 : NSObject
+- (instancetype)init;
+@end
+
+__attribute__((availability(domain:GoldenGateBridge, AVAIL)))
+@interface ImplementMeGoldenGateBridgeAvailable3 : NSObject
+- (instancetype)init;
+@end
+
+__attribute__((availability(domain:GoldenGateBridge, UNAVAIL)))
+@interface ImplementMeGoldenGateBridgeUnavailable : NSObject
+- (instancetype)init;
+@end
+
+#endif // __OBJC__
+
+#undef UNAVAIL
+#undef AVAIL
diff --git a/test/ClangImporter/Inputs/c-bridging-header.h b/test/ClangImporter/Inputs/c-bridging-header.h
new file mode 100644
index 0000000000000..5dc00a6d1a586
--- /dev/null
+++ b/test/ClangImporter/Inputs/c-bridging-header.h
@@ -0,0 +1,12 @@
+#ifndef C_BRIDGING_HEADER_H
+#define C_BRIDGING_HEADER_H
+
+#include "ctypes.h"
+#include "macros.h"
+
+typedef struct {
+  double x, y;
+} MyPoint;
+
+typedef double MyDouble;
+#endif
diff --git a/test/ClangImporter/Inputs/custom-modules/Aliases.h b/test/ClangImporter/Inputs/custom-modules/Aliases.h
new file mode 100644
index 0000000000000..b078f53ef5648
--- /dev/null
+++ b/test/ClangImporter/Inputs/custom-modules/Aliases.h
@@ -0,0 +1,53 @@
+#pragma once
+
+#if defined(UNICODE)
+#define F FW
+#define V VW
+#else
+#define F FA
+#define V VA
+#endif
+
+#if defined(_WIN32)
+#define ALIASES_ABI /**/
+#else
+#define ALIASES_ABI __attribute__((__visibility__("default")))
+#endif
+
+extern ALIASES_ABI const unsigned int VA;
+extern ALIASES_ABI const unsigned long long VW;
+
+ALIASES_ABI void FA(unsigned int);
+ALIASES_ABI void FW(unsigned long long);
+
+#define InvalidCall DoesNotExist
+
+extern ALIASES_ABI float UIA;
+extern ALIASES_ABI double UIW;
+
+#if defined(UNICODE)
+#define UI UIW
+#else
+#define UI UIA
+#endif
+
+enum {
+  ALPHA = 0,
+#define ALPHA ALPHA
+  BETA = 1,
+#define BETA BETA
+};
+
+enum {
+  _CLOCK_MONOTONIC __attribute__((__swift_name__("CLOCK_MONOTONIC"))),
+#define CLOCK_MONOTONIC _CLOCK_MONOTONIC
+} _clock_t;
+
+enum : int {
+  overloaded,
+};
+#define overload overloaded
+extern const int const_overloaded __attribute__((__swift_name__("overload")));
+
+void variadic(int count, ...);
+#define aliased_variadic variadic
diff --git a/test/ClangImporter/Inputs/custom-modules/CVarArgs.h b/test/ClangImporter/Inputs/custom-modules/CVarArgs.h
new file mode 100644
index 0000000000000..53fd7057a11d0
--- /dev/null
+++ b/test/ClangImporter/Inputs/custom-modules/CVarArgs.h
@@ -0,0 +1,7 @@
+#include <stdarg.h>
+extern void takeVaList(va_list args);
+
+extern void takeVaList2(__builtin_va_list args);
+
+typedef __builtin_va_list my_builtin_va_list_alias;
+extern void takeVaList3(my_builtin_va_list_alias args);
diff --git a/test/ClangImporter/Inputs/custom-modules/ImportAsMember.h b/test/ClangImporter/Inputs/custom-modules/ImportAsMember.h
index b3897bafe3f62..ef91710530241 100644
--- a/test/ClangImporter/Inputs/custom-modules/ImportAsMember.h
+++ b/test/ClangImporter/Inputs/custom-modules/ImportAsMember.h
@@ -70,8 +70,8 @@ typedef float MNInnerFloat __attribute__((swift_name("IAMMultipleNested.Inner"))
 
 typedef int IAMBadInnerInt
     __attribute__((swift_name("IAMNonexistent.Inner")));
-// CHECK: ImportAsMember.h:[[@LINE-1]]:{{[0-9]+}}: warning: imported declaration 'IAMBadInnerInt' could not be mapped to 'IAMNonexistent.Inner'
-// CHECK: note: please report this issue to the owners of 'ImportAsMember'
+// CHECK: ImportAsMember.h:[[@LINE-1]]:{{[0-9]+}}: warning: imported declaration 'IAMBadInnerInt' could not be mapped to 'IAMNonexistent.Inner' [#ClangDeclarationImport]
+// CHECK: note: please report this issue to the owners of 'ImportAsMember' [#ClangDeclarationImport]
 typedef int IAMBadInnerIntAPINotes;
 // CHECK: ImportAsMember.h:[[@LINE-1]]:{{[0-9]+}}: warning: imported declaration 'IAMBadInnerIntAPINotes' could not be mapped to 'IAMNonexistent.Inner2'
 // CHECK: note: please report this issue to the owners of 'ImportAsMember'
diff --git a/test/ClangImporter/Inputs/custom-modules/MacOSVersionCanonicalization.h b/test/ClangImporter/Inputs/custom-modules/MacOSVersionCanonicalization.h
index b0b02c20e999b..c7e345a632eab 100644
--- a/test/ClangImporter/Inputs/custom-modules/MacOSVersionCanonicalization.h
+++ b/test/ClangImporter/Inputs/custom-modules/MacOSVersionCanonicalization.h
@@ -4,8 +4,20 @@ void FunctionIntroducedIn10_16();
 __attribute__((availability(macosx,introduced=11.0)))
 void FunctionIntroducedIn11_0();
 
+__attribute__((availability(macosx,introduced=16.0)))
+void FunctionIntroducedIn16_0();
+
+__attribute__((availability(macosx,introduced=26.0)))
+void FunctionIntroducedIn26_0();
+
 __attribute__((availability(macosx_app_extension,introduced=10.16)))
 void FunctionIntroducedIn10_16AppExt();
 
 __attribute__((availability(macosx_app_extension,introduced=11.0)))
 void FunctionIntroducedIn11_0AppExt();
+
+__attribute__((availability(macosx_app_extension,introduced=16.0)))
+void FunctionIntroducedIn16_0AppExt();
+
+__attribute__((availability(macosx_app_extension,introduced=26.0)))
+void FunctionIntroducedIn26_0AppExt();
diff --git a/test/ClangImporter/Inputs/custom-modules/availability-domains/Oceans.h b/test/ClangImporter/Inputs/custom-modules/availability-domains/Oceans.h
deleted file mode 100644
index fb8f235b15164..0000000000000
--- a/test/ClangImporter/Inputs/custom-modules/availability-domains/Oceans.h
+++ /dev/null
@@ -1,28 +0,0 @@
-#import <Rivers.h>
-#include <feature-availability.h>
-
-int arctic_pred(void);
-int pacific_pred(void);
-
-static struct __AvailabilityDomain __Arctic
-    __attribute__((availability_domain(Arctic))) = {
-        __AVAILABILITY_DOMAIN_DYNAMIC, arctic_pred};
-static struct __AvailabilityDomain __Pacific
-    __attribute__((availability_domain(Pacific))) = {
-        __AVAILABILITY_DOMAIN_DYNAMIC, pacific_pred};
-
-#define AVAIL 0
-#define UNAVAIL 1
-
-__attribute__((availability(domain:Arctic, AVAIL)))
-void available_in_arctic(void);
-
-__attribute__((availability(domain:Pacific, UNAVAIL)))
-void unavailable_in_pacific(void);
-
-__attribute__((availability(domain:Colorado, AVAIL)))
-__attribute__((availability(domain:Pacific, AVAIL)))
-void available_in_colorado_river_delta(void);
-
-#undef UNAVAIL
-#undef AVAIL
diff --git a/test/ClangImporter/Inputs/custom-modules/availability-domains/Rivers.h b/test/ClangImporter/Inputs/custom-modules/availability-domains/Rivers.h
deleted file mode 100644
index 00aca3bdbb623..0000000000000
--- a/test/ClangImporter/Inputs/custom-modules/availability-domains/Rivers.h
+++ /dev/null
@@ -1,13 +0,0 @@
-#include <feature-availability.h>
-
-static struct __AvailabilityDomain __Colorado __attribute__((
-    availability_domain(Colorado))) = {__AVAILABILITY_DOMAIN_DISABLED, 0};
-
-#define AVAIL 0
-#define UNAVAIL 1
-
-__attribute__((availability(domain:Colorado, AVAIL)))
-void available_in_colorado(void);
-
-#undef UNAVAIL
-#undef AVAIL
diff --git a/test/ClangImporter/Inputs/custom-modules/availability-domains/Seas.h b/test/ClangImporter/Inputs/custom-modules/availability-domains/Seas.h
deleted file mode 100644
index da1cd046b6abe..0000000000000
--- a/test/ClangImporter/Inputs/custom-modules/availability-domains/Seas.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#include <feature-availability.h>
-
-static struct __AvailabilityDomain __Baltic __attribute__((
-    availability_domain(Baltic))) = {__AVAILABILITY_DOMAIN_ENABLED, 0};
-static struct __AvailabilityDomain __Mediterranean __attribute__((
-    availability_domain(Mediterranean))) = {__AVAILABILITY_DOMAIN_ENABLED, 0};
-
-#define AVAIL 0
-#define UNAVAIL 1
-
-__attribute__((availability(domain:Baltic, AVAIL)))
-void available_in_baltic(void);
-
-#undef UNAVAIL
-#undef AVAIL
diff --git a/test/ClangImporter/Inputs/custom-modules/availability-domains/module.modulemap b/test/ClangImporter/Inputs/custom-modules/availability-domains/module.modulemap
deleted file mode 100644
index 62930e7c437ab..0000000000000
--- a/test/ClangImporter/Inputs/custom-modules/availability-domains/module.modulemap
+++ /dev/null
@@ -1,14 +0,0 @@
-module Oceans {
-  header "Oceans.h"
-  export *
-}
-
-module Rivers {
-  header "Rivers.h"
-  export *
-}
-
-module Seas {
-  header "Seas.h"
-  export *
-}
diff --git a/test/ClangImporter/Inputs/custom-modules/module.modulemap b/test/ClangImporter/Inputs/custom-modules/module.modulemap
index a827a3474db82..b37985ec675e0 100644
--- a/test/ClangImporter/Inputs/custom-modules/module.modulemap
+++ b/test/ClangImporter/Inputs/custom-modules/module.modulemap
@@ -275,3 +275,16 @@ module CommonName {
 module "Weird C Module" {
   header "WeirdCModule.h"
 }
+
+module Aliases {
+  header "Aliases.h"
+}
+
+module RetroactiveVersioning {
+  header "versioning.h"
+}
+
+module CVarArgs {
+  header "CVarArgs.h"
+  export *
+}
diff --git a/test/ClangImporter/Inputs/custom-modules/versioning.h b/test/ClangImporter/Inputs/custom-modules/versioning.h
new file mode 100644
index 0000000000000..dcc6bb0840ee7
--- /dev/null
+++ b/test/ClangImporter/Inputs/custom-modules/versioning.h
@@ -0,0 +1,9 @@
+#pragma once
+extern const int kVersion;
+extern const int kVersion1;
+extern const int kVersion2;
+#if OLD_DEPLOYMENT_TARGET
+#define kVersion kVersion1
+#else
+#define kVersion kVersion2
+#endif
diff --git a/test/ClangImporter/Inputs/cxx-bridging-header.h b/test/ClangImporter/Inputs/cxx-bridging-header.h
new file mode 100644
index 0000000000000..d792ba4ecc409
--- /dev/null
+++ b/test/ClangImporter/Inputs/cxx-bridging-header.h
@@ -0,0 +1,9 @@
+
+namespace OuterNS {
+  class MyPoint {
+  public:
+    double x, y;
+  };
+}
+
+#include "cxx-outer-ns.h"
diff --git a/test/ClangImporter/Inputs/cxx-outer-ns.h b/test/ClangImporter/Inputs/cxx-outer-ns.h
new file mode 100644
index 0000000000000..d9d78404852f4
--- /dev/null
+++ b/test/ClangImporter/Inputs/cxx-outer-ns.h
@@ -0,0 +1,7 @@
+namespace OuterNS {
+  enum Color {
+    red,
+    green,
+    blue
+  };
+}
diff --git a/test/ClangImporter/Inputs/module.modulemap b/test/ClangImporter/Inputs/module.modulemap
new file mode 100644
index 0000000000000..296486613ab8c
--- /dev/null
+++ b/test/ClangImporter/Inputs/module.modulemap
@@ -0,0 +1,3 @@
+module CXXOuterNS {
+  header "cxx-outer-ns.h"
+}
diff --git a/test/ClangImporter/Inputs/regionbasedisolation.h b/test/ClangImporter/Inputs/regionbasedisolation.h
new file mode 100644
index 0000000000000..6385570570d3e
--- /dev/null
+++ b/test/ClangImporter/Inputs/regionbasedisolation.h
@@ -0,0 +1,21 @@
+
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface ObjCObject : NSObject
+
+- (void)loadObjectsWithCompletionHandler:
+    (void (^NS_SWIFT_SENDABLE)(NSArray<NSObject *> *_Nullable,
+                               NSError *_Nullable))completionHandler;
+
+- (void)loadObjects2WithCompletionHandler:
+    (void (^)(NSArray<NSObject *> *_Nullable,
+                               NSError *_Nullable))completionHandler;
+
+- (void)useValue:(id)object
+    withCompletionHandler:(void (^)(NSObject *_Nullable))completionHandler;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/test/ClangImporter/Inputs/sending.h b/test/ClangImporter/Inputs/sending.h
index 04f037caf414c..a3b8602d5c8d0 100644
--- a/test/ClangImporter/Inputs/sending.h
+++ b/test/ClangImporter/Inputs/sending.h
@@ -43,4 +43,7 @@ sendUserDefinedFromGlobalFunction(NonSendableCStruct other) SWIFT_SENDING;
 void sendUserDefinedIntoGlobalFunction(
     NonSendableCStruct arg SWIFT_SENDING);
 
+void sendingWithCompletionHandler(void (^completion)(SWIFT_SENDING NonSendableCStruct arg));
+SWIFT_SENDING NonSendableCStruct sendingWithLazyReturn(SWIFT_SENDING NonSendableCStruct (^makeLazily)(void));
+
 #pragma clang assume_nonnull end
diff --git a/test/ClangImporter/InternalBridgingHeader/access_checking.swift b/test/ClangImporter/InternalBridgingHeader/access_checking.swift
new file mode 100644
index 0000000000000..d1cf5c6ef5229
--- /dev/null
+++ b/test/ClangImporter/InternalBridgingHeader/access_checking.swift
@@ -0,0 +1,39 @@
+// RUN: %empty-directory(%t)
+// RUN: mkdir -p %t/tmp
+
+// Test with the normal bridging header.
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk
+
+// Test with a precompiled bridging header.
+// RUN: %target-swift-frontend -emit-pch -o %t/c-bridging-header.pch %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -internal-import-bridging-header %t/c-bridging-header.pch -sdk %clang-importer-sdk
+
+
+// Overrides the internal import that comes through the bridging header.
+public import macros
+
+public func getRed() -> Color { red } // expected-error{{function cannot be declared public because its result uses an internal type}}
+// expected-note@-1{{struct 'Color' is imported by this file as 'internal' from bridging header}}
+
+public func getX(point: MyPoint) -> Double { point.x } // expected-error{{function cannot be declared public because its parameter uses an internal type}}
+// expected-note@-1{{struct 'MyPoint' is imported by this file as 'internal' from bridging header}}
+
+// Comes from the macros module.
+public func returnsFromMacrosModule() -> okay_t { 0 }
+
+public protocol P {
+  associatedtype A
+}
+
+public struct MyType: P {
+  public typealias A = MyDouble
+  // expected-error@-1{{type alias cannot be declared public because its underlying type uses an internal type}}
+  // expected-note@-2{{type alias 'MyDouble' is imported by this file as 'internal' from bridging header}}
+}
+
+// expected-error@+1{{cannot use struct 'MyPoint' in an extension with public or '@usableFromInline' members; it was imported via the internal bridging header}}
+extension MyPoint: P {
+  public typealias A = MyDouble
+  // expected-error@-1{{type alias cannot be declared public because its underlying type uses an internal type}}
+  // expected-note@-2{{type alias 'MyDouble' is imported by this file as 'internal' from bridging header}}
+}
diff --git a/test/ClangImporter/InternalBridgingHeader/access_checking_cxx.swift b/test/ClangImporter/InternalBridgingHeader/access_checking_cxx.swift
new file mode 100644
index 0000000000000..50fd13944eafd
--- /dev/null
+++ b/test/ClangImporter/InternalBridgingHeader/access_checking_cxx.swift
@@ -0,0 +1,9 @@
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -internal-import-bridging-header %S/../Inputs/cxx-bridging-header.h -sdk %clang-importer-sdk -cxx-interoperability-mode=default -I %S/../Inputs
+
+public func getRed() -> OuterNS.Color { OuterNS.red }
+// expected-error@-1{{function cannot be declared public because its result uses an internal type}}
+// expected-note@-2{{enum 'OuterNS' is imported by this file as 'internal' from bridging header}}
+
+public func getX(point: OuterNS.MyPoint) -> Double { point.x }
+// expected-error@-1{{function cannot be declared public because its parameter uses an internal type}}
+// expected-note@-2{{enum 'OuterNS' is imported by this file as 'internal' from bridging header}}
diff --git a/test/ClangImporter/InternalBridgingHeader/implementation_only_checking.swift b/test/ClangImporter/InternalBridgingHeader/implementation_only_checking.swift
new file mode 100644
index 0000000000000..912f3546b4a8f
--- /dev/null
+++ b/test/ClangImporter/InternalBridgingHeader/implementation_only_checking.swift
@@ -0,0 +1,21 @@
+// RUN: %empty-directory(%t)
+// RUN: mkdir -p %t/tmp
+
+// Test with the normal bridging header.
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk -verify-ignore-unknown
+
+// RUN: not %target-swift-frontend -typecheck -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk %s 2>&1 | %FileCheck %s
+
+// Test with a precompiled bridging header.
+// RUN: %target-swift-frontend -emit-pch -o %t/c-bridging-header.pch %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -internal-import-bridging-header %t/c-bridging-header.pch -sdk %clang-importer-sdk -verify-ignore-unknown
+
+
+@inlinable
+public func f() -> Any {
+  return red
+  // expected-error@-1{{var 'red' is internal and cannot be referenced from an '@inlinable' function}}
+  // expected-warning@-2{{getter for var 'red' is internal and should not be referenced from an '@inlinable' function}}
+}
+
+// CHECK: var 'red' imported as 'internal' from bridging header
diff --git a/test/ClangImporter/InternalBridgingHeader/interface.swift b/test/ClangImporter/InternalBridgingHeader/interface.swift
new file mode 100644
index 0000000000000..f6ea1825348fe
--- /dev/null
+++ b/test/ClangImporter/InternalBridgingHeader/interface.swift
@@ -0,0 +1,14 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-emit-module-interface(%t/MyModule.swiftinterface) %s -module-name MyModule -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk -enable-library-evolution
+
+// RUN: %FileCheck %s < %t/MyModule.swiftinterface
+
+// CHECK-NOT: internal-import-bridging-header
+
+// CHECK: public func g()
+
+func getX(point: MyPoint) -> Double { point.x }
+
+public func g() {
+}
diff --git a/test/ClangImporter/InternalBridgingHeader/library_evolution.swift b/test/ClangImporter/InternalBridgingHeader/library_evolution.swift
new file mode 100644
index 0000000000000..df3b9de4bf58e
--- /dev/null
+++ b/test/ClangImporter/InternalBridgingHeader/library_evolution.swift
@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk %s 2>&1 | %FileCheck -check-prefix NONRESILIENT %s
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk %s -enable-library-evolution 2>&1 | %FileCheck -check-prefix EVOLUTION %s
+
+// NONRESILIENT: warning: using internal bridging headers without library evolution can cause instability
+
+// EVOLUTION-NOT: internal bridging head
+
+@available(*, deprecated)
+func f() { }
+
+func g(){
+  f() // make sure we emit something
+}
diff --git a/test/ClangImporter/InternalBridgingHeader/pch.swift b/test/ClangImporter/InternalBridgingHeader/pch.swift
new file mode 100644
index 0000000000000..d0b65ffe8a993
--- /dev/null
+++ b/test/ClangImporter/InternalBridgingHeader/pch.swift
@@ -0,0 +1,52 @@
+// RUN: %empty-directory(%t)
+// RUN: mkdir -p %t/tmp
+
+// First test the explicit frontend-based bridging PCH generation and use works
+// RUN: %target-swift-frontend -emit-pch -o %t/c-bridging-header.pch %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk
+// RUN: %target-typecheck-verify-swift -internal-import-bridging-header %t/c-bridging-header.pch -sdk %clang-importer-sdk
+
+// Now test the driver-automated version is inert when disabled
+// Output path of the PCH differs in the new driver, so force SWIFT_USE_OLD_DRIVER for now.
+// RUN: env TMPDIR=%t/tmp/ SWIFT_USE_OLD_DRIVER=1 %target-swiftc_driver -typecheck -disable-bridging-pch -save-temps %s -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk
+// RUN: not ls %t/tmp/*.pch >/dev/null 2>&1
+
+// Test the driver-automated version works by default
+// Output path of the PCH differs in the new driver, so force SWIFT_USE_OLD_DRIVER for now.
+// RUN: env TMPDIR=%t/tmp/ SWIFT_USE_OLD_DRIVER=1 %target-swiftc_driver -typecheck -save-temps %s -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk
+// RUN: ls %t/tmp/*.pch >/dev/null 2>&1
+// RUN: llvm-objdump --raw-clang-ast %t/tmp/*.pch | llvm-bcanalyzer -dump | %FileCheck %s
+// CHECK: ORIGINAL_FILE{{.*}}Inputs/c-bridging-header.h
+
+// Test the driver-automated version deletes its PCH file when done
+// RUN: rm %t/tmp/*.pch
+// RUN: env TMPDIR=%t/tmp/ %target-swiftc_driver -typecheck %s -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk
+// RUN: not ls %t/tmp/*.pch >/dev/null 2>&1
+
+// Test -emit-pch invocation but with a persistent PCH
+// RUN: %target-swift-frontend -emit-pch -pch-output-dir %t/pch %S/../Inputs/c-bridging-header.h -sdk %clang-importer-sdk
+// RUN: %target-typecheck-verify-swift -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -pch-output-dir %t/pch -pch-disable-validation -sdk %clang-importer-sdk
+// RUN: ls %t/pch/*.pch >/dev/null 2>&1
+
+// Test implicit use of persistent PCH
+// RUN: %target-typecheck-verify-swift -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -pch-output-dir %t/pch2 -sdk %clang-importer-sdk
+// RUN: ls %t/pch2/*.pch >/dev/null 2>&1
+
+// RUN: touch %t/header.with.dot.h
+// RUN: touch %t/test.swift
+// RUN: %target-swift-frontend -typecheck %t/test.swift -internal-import-bridging-header %t/header.with.dot.h -pch-output-dir %t/pch_with_dot -module-cache-path %t/mcp1 -sdk %clang-importer-sdk
+// RUN: %target-swift-frontend -typecheck %t/test.swift -internal-import-bridging-header %t/header.with.dot.h -pch-output-dir %t/pch_with_dot -module-cache-path %t/mcp2 -sdk %clang-importer-sdk
+// RUN: ls %t/pch_with_dot/*swift*clang*.pch | count 2
+
+// Test the driver-automated version using persistent PCH
+// RUN: %target-swiftc_driver -typecheck -save-temps %s -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -pch-output-dir %t/pch3 -sdk %clang-importer-sdk
+// RUN: ls %t/pch3/*.pch >/dev/null 2>&1
+// RUN: llvm-objdump --raw-clang-ast %t/pch3/*.pch | llvm-bcanalyzer -dump | %FileCheck %s -check-prefix=PERSISTENT
+// PERSISTENT: ORIGINAL_FILE{{.*}}Inputs/c-bridging-header.h
+
+// Test that -pch-disable-validation works in that it won't implicitly create a PCH
+// RUN: not %target-swift-frontend -typecheck %s -internal-import-bridging-header %S/../Inputs/c-bridging-header.h -pch-output-dir %t/no-pch -pch-disable-validation -sdk %clang-importer-sdk 2>&1 | %FileCheck %s -check-prefix=NO-VALIDATION
+// NO-VALIDATION: PCH file {{.*}} not found
+
+// UNSUPPORTED: OS=windows-msvc
+
+func getX(point: MyPoint) -> Double { point.x }
diff --git a/test/ClangImporter/InternalBridgingHeader/serialization.swift b/test/ClangImporter/InternalBridgingHeader/serialization.swift
new file mode 100644
index 0000000000000..499d2b883a4ce
--- /dev/null
+++ b/test/ClangImporter/InternalBridgingHeader/serialization.swift
@@ -0,0 +1,48 @@
+// RUN: %empty-directory(%t)
+
+// Stage in the headers we need
+// RUN: mkdir %t/headers
+// RUN: cp %S/../Inputs/c-bridging-header.h %t/headers
+
+// RUN: mkdir %t/src
+// RUN: split-file %s %t/src
+
+// Build a module
+// RUN: mkdir %t/modules
+// RUN: %target-swift-frontend -internal-import-bridging-header %t/headers/c-bridging-header.h -sdk %clang-importer-sdk -emit-module -o %t/modules/MyModule.swiftmodule %t/src/MyModule.swift
+
+// Check that there's no serialized bridging header in the module file.
+// RUN: llvm-bcanalyzer -dump %t/modules/MyModule.swiftmodule | %FileCheck -check-prefix MODULE-FILE %s
+
+// Use the module.
+// RUN: %target-swift-frontend -typecheck -sdk %clang-importer-sdk -I %t/modules %t/src/MyClient.swift
+
+// Delete the bridging header, and again use the module.
+// RUN: rm %t/headers/c-bridging-header.h
+// RUN: %target-swift-frontend -typecheck -sdk %clang-importer-sdk -I %t/modules %t/src/MyClient.swift
+
+//--- MyModule.swift
+func getRed() -> Color { red }
+
+func getX(point: MyPoint) -> Double { point.x }
+
+public func f() {
+  _ = getRed()
+}
+
+//--- MyClient.swift
+
+import MyModule
+
+func g() {
+  f()
+}
+
+
+// MODULE-FILE-NOT: IMPORTED_HEADER
+// MODULE-FILE-NOT: IMPORTED_HEADER_CONTENTS
+
+// MODULE-FILE: SEARCH_PATH
+
+// MODULE-FILE-NOT: IMPORTED_HEADER
+// MODULE-FILE-NOT: IMPORTED_HEADER_CONTENTS
diff --git a/test/ClangImporter/MixedSource/broken-bridging-header.swift b/test/ClangImporter/MixedSource/broken-bridging-header.swift
index c3dde966b976b..de0b70c5fc233 100644
--- a/test/ClangImporter/MixedSource/broken-bridging-header.swift
+++ b/test/ClangImporter/MixedSource/broken-bridging-header.swift
@@ -10,11 +10,11 @@
 
 // RUN: %target-swift-frontend -emit-module -o %t -module-name HasBridgingHeader %S/../../Inputs/empty.swift -enable-objc-interop -import-objc-header %t/error-on-define.h -diagnostic-style llvm
 
-// RUN: %target-swift-frontend -typecheck %s -I %t -Xcc -DERROR -verify -show-diagnostics-after-fatal
+// RUN: %target-swift-frontend -typecheck %s -I %t -Xcc -DERROR -verify -verify-ignore-unrelated -show-diagnostics-after-fatal
 // RUN: not %target-swift-frontend -typecheck %s -I %t -Xcc -DERROR 2>&1 -diagnostic-style llvm | %FileCheck -check-prefix=HEADER-ERROR %s
 
 // RUN: rm %t/error-on-define-impl.h
-// RUN: %target-swift-frontend -typecheck %s -I %t -verify -show-diagnostics-after-fatal -diagnostic-style llvm
+// RUN: %target-swift-frontend -typecheck %s -I %t -verify -verify-ignore-unrelated -show-diagnostics-after-fatal -diagnostic-style llvm
 // RUN: not %target-swift-frontend -typecheck %s -I %t -diagnostic-style llvm 2>&1 | %FileCheck -check-prefix=MISSING-OTHER-HEADER %s
 
 import HasBridgingHeader // expected-error {{failed to import bridging header}} expected-error {{failed to load module 'HasBridgingHeader'}}
diff --git a/test/ClangImporter/MixedSource/can_import_objc_idempotent.swift b/test/ClangImporter/MixedSource/can_import_objc_idempotent.swift
index 9ba34ebaa4320..1f38fde8bc2cb 100644
--- a/test/ClangImporter/MixedSource/can_import_objc_idempotent.swift
+++ b/test/ClangImporter/MixedSource/can_import_objc_idempotent.swift
@@ -7,10 +7,10 @@
 // FIXME: END -enable-source-import hackaround
 
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -I %S/../Inputs/custom-modules -enable-objc-interop -import-objc-header %t/mixed-target/header.h -emit-module-path %t/MixedWithHeader.swiftmodule %S/Inputs/mixed-with-header.swift %S/../../Inputs/empty.swift -module-name MixedWithHeader -disable-objc-attr-requires-foundation-module
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -I %S/../Inputs/custom-modules -typecheck %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -I %S/../Inputs/custom-modules -typecheck %s -verify -verify-ignore-unrelated
 
 // RUN: rm -rf %t/mixed-target/
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -I %S/../Inputs/custom-modules -typecheck %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -I %S/../Inputs/custom-modules -typecheck %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/MixedSource/import-mixed-framework.swift b/test/ClangImporter/MixedSource/import-mixed-framework.swift
index 8ce4b8b78da57..aeb522739cd3c 100644
--- a/test/ClangImporter/MixedSource/import-mixed-framework.swift
+++ b/test/ClangImporter/MixedSource/import-mixed-framework.swift
@@ -5,7 +5,7 @@
 // RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -F %t -typecheck %s
 
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -emit-module -o %t/Mixed.framework/Modules/Mixed.swiftmodule/%target-swiftmodule-name %S/Inputs/mixed-framework/Mixed.swift -import-underlying-module -F %t -module-name Mixed -disable-objc-attr-requires-foundation-module
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -F %t -typecheck %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -F %t -typecheck %s -verify -verify-ignore-unrelated
 
 import Mixed
 
diff --git a/test/ClangImporter/MixedSource/mixed-target-using-header.swift b/test/ClangImporter/MixedSource/mixed-target-using-header.swift
index 48581ef5812aa..5c777c703bc9f 100644
--- a/test/ClangImporter/MixedSource/mixed-target-using-header.swift
+++ b/test/ClangImporter/MixedSource/mixed-target-using-header.swift
@@ -66,11 +66,13 @@ func testProtocolNamingConflict() {
   let a: ConflictingName1?
   var b: ConflictingName1Protocol?
   b = a // expected-error {{cannot assign value of type 'ConflictingName1?' to type '(any ConflictingName1Protocol)?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('ConflictingName1' and 'any ConflictingName1Protocol') are expected to be equal}}
   _ = b
 
   let c: ConflictingName2?
   var d: ConflictingName2Protocol?
   d = c // expected-error {{cannot assign value of type 'ConflictingName2?' to type '(any ConflictingName2Protocol)?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('ConflictingName2' and 'any ConflictingName2Protocol') are expected to be equal}}
   _ = d
 }
 
diff --git a/test/ClangImporter/MixedSource/mixed-target-using-module.swift b/test/ClangImporter/MixedSource/mixed-target-using-module.swift
index 7cacecc69c4fd..c258371b3f26d 100644
--- a/test/ClangImporter/MixedSource/mixed-target-using-module.swift
+++ b/test/ClangImporter/MixedSource/mixed-target-using-module.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -F %S/Inputs/mixed-target/ -module-name Mixed -import-underlying-module -typecheck %s -verify -enable-objc-interop -disable-objc-attr-requires-foundation-module
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -F %S/Inputs/mixed-target/ -module-name Mixed -import-underlying-module -typecheck %s -verify -verify-ignore-unrelated -enable-objc-interop -disable-objc-attr-requires-foundation-module
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -F %S/Inputs/mixed-target/ -module-name Mixed -import-underlying-module -enable-objc-interop -emit-ir %S/../../Inputs/empty.swift | %FileCheck -check-prefix=CHECK-AUTOLINK %s
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -F %S/Inputs/mixed-target/ -module-name Mixed -DOVERLAY_STYLE_RIGHT -enable-objc-interop -emit-ir %S/../../Inputs/empty.swift | %FileCheck -check-prefix=CHECK-AUTOLINK %s
 // RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -F %S/Inputs/mixed-target/ -module-name WrongName -import-underlying-module -typecheck %s  -enable-objc-interop -disable-objc-attr-requires-foundation-module 2>&1 | %FileCheck -check-prefix=CHECK-WRONG-NAME %s
diff --git a/test/ClangImporter/MixedSource/resolve-cross-language.swift b/test/ClangImporter/MixedSource/resolve-cross-language.swift
index f64c280ad4820..c0dcd972949f9 100644
--- a/test/ClangImporter/MixedSource/resolve-cross-language.swift
+++ b/test/ClangImporter/MixedSource/resolve-cross-language.swift
@@ -2,7 +2,7 @@
 
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -emit-module -enable-objc-interop -emit-objc-header -o %t %S/Inputs/resolve-cross-language/Base.swift -disable-objc-attr-requires-foundation-module
 // RUN: cp %S/Inputs/resolve-cross-language/Base.modulemap %t/module.modulemap
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -I %t -F %clang-importer-sdk-path/frameworks -F %S/Inputs/resolve-cross-language %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -I %t -F %clang-importer-sdk-path/frameworks -F %S/Inputs/resolve-cross-language %s -verify -verify-ignore-unrelated
 
 import Base
 import BaseUser
diff --git a/test/ClangImporter/SceneKit_test.swift b/test/ClangImporter/SceneKit_test.swift
index 05dc38b52e6a0..7d155109821f9 100644
--- a/test/ClangImporter/SceneKit_test.swift
+++ b/test/ClangImporter/SceneKit_test.swift
@@ -1,4 +1,5 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %empty-directory(%t/cache)
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -module-cache-path %t/cache
 
 // REQUIRES: objc_interop
 // REQUIRES: OS=macosx
diff --git a/test/ClangImporter/alias-invalid.swift b/test/ClangImporter/alias-invalid.swift
new file mode 100644
index 0000000000000..ab6bc626b8f8b
--- /dev/null
+++ b/test/ClangImporter/alias-invalid.swift
@@ -0,0 +1,22 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs/custom-modules -enable-experimental-feature ImportMacroAliases
+
+// REQUIRES: swift_feature_ImportMacroAliases
+
+import Aliases
+
+func f() {
+  InvalidCall() // expected-error{{cannot find 'InvalidCall' in scope}}
+}
+
+func g() {
+  V = 32 // expected-error{{cannot assign to value: 'V' is a get-only property}}
+}
+
+func h() {
+  let _ = overload // expected-error{{ambiguous use of 'overload'}}
+}
+
+func i() {
+  aliased_variadic(0, 0) // expected-error{{cannot find 'aliased_variadic' in scope}}
+}
diff --git a/test/ClangImporter/alias.swift b/test/ClangImporter/alias.swift
new file mode 100644
index 0000000000000..be583908087f3
--- /dev/null
+++ b/test/ClangImporter/alias.swift
@@ -0,0 +1,66 @@
+// RUN: %target-typecheck-verify-swift -I %S/Inputs/custom-modules %s -enable-experimental-feature ImportMacroAliases
+// RUN: %target-swift-frontend -I %S/Inputs/custom-modules -parse-as-library -module-name Alias -Osize -emit-ir -o - %s -enable-experimental-feature ImportMacroAliases | %FileCheck %s -check-prefix CHECK-ANSI-IR
+// RUN: %target-typecheck-verify-swift -I %S/Inputs/custom-modules %s -Xcc -DUNICODE -enable-experimental-feature ImportMacroAliases
+// RUN: %target-swift-frontend -I %S/Inputs/custom-modules -parse-as-library -module-name Alias -Osize -emit-ir -o - %s -Xcc -DUNICODE -enable-experimental-feature ImportMacroAliases | %FileCheck %s -check-prefix CHECK-UNICODE-IR
+// RUN: not %target-swift-frontend -I %S/Inputs/custom-modules -parse-as-library -module-name Alias -c %s -DINVALID -o /dev/null 2>&1 -enable-experimental-feature ImportMacroAliases | %FileCheck --dry-run %s -check-prefix CHECK-INVALID
+
+// REQUIRES: swift_feature_ImportMacroAliases
+
+// expected-no-diagnostics
+
+import Aliases
+
+public func f() {
+  F(V)
+}
+
+public func g() {
+  UI = 32
+}
+
+// CHECK-ANSI-IR: @VA = external {{(dso_local )?}}local_unnamed_addr constant i32
+// CHECK-ANSI-IR: @UIA = external {{(dso_local )?}}local_unnamed_addr global float
+
+// CHECK-ANSI-IR: define {{.*}}swiftcc void @"$s5Alias1fyyF"(){{.*}}{
+// CHECK-ANSI-IR: entry:
+// CHECK-ANSI-IR:   %0 = load i32, ptr @VA
+// CHECK-ANSI-IR:   tail call void @FA(i32 %0)
+// CHECK-ANSI-IR:   ret void
+// CHECK-ANSI-IR: }
+
+// CHECK-ANSI-IR: declare {{.*}}void @FA(i32 noundef)
+// CHECK-ANSI-IR-NOT: declare {{.*}}void @FW(i64 noundef)
+
+// CHECK-ANSI-IR: define {{.*}}swiftcc void @"$s5Alias1gyyF"(){{.*}}{
+// CHECK-ANSI-IR: entry:
+// CHECK-ANSI-IR:   store float 3.200000e+01, ptr @UIA
+// CHECK-ANSI-IR:   ret void
+// CHECK-ANSI-IR: }
+
+// CHECK-UNICODE-IR: @VW = external {{(dso_local )?}}local_unnamed_addr constant i64
+// CHECK-UNICODE-IR: @UIW = external {{(dso_local )?}}local_unnamed_addr global double
+
+// CHECK-UNICODE-IR: define {{.*}}swiftcc void @"$s5Alias1fyyF"(){{.*}}{
+// CHECK-UNICODE-IR: entry:
+// CHECK-UNICODE-IR:   %0 = load i64, ptr @VW
+// CHECK-UNICODE-IR:   tail call void @FW(i64 %0)
+// CHECK-UNICODE-IR:   ret void
+// CHECK-UNICODE-IR: }
+
+// CHECK-UNICODE-IR: declare {{(dso_local )?}}void @FW(i64 noundef)
+// CHECK-UNICODE-IR-NOT: declare {{(dso_local )?}}void @FA(i32 noundef)
+
+// CHECK-UNICODE-IR: define {{.*}}swiftcc void @"$s5Alias1gyyF"(){{.*}}{
+// CHECK-UNICODE-IR: entry:
+// CHECK-UNICODE-IR:   store double 3.200000e+01, ptr @UIW
+// CHECK-UNICODE-IR:   ret void
+// CHECK-UNICODE-IR: }
+
+func h() {
+  let _ = CLOCK_MONOTONIC
+}
+
+#if INVALID
+let _ = ALPHA
+// CHECK-INVALID: error: global variable declaration does not bind any variables
+#endif
diff --git a/test/ClangImporter/attr-swift_name-errors.swift b/test/ClangImporter/attr-swift_name-errors.swift
index 10143e9e00f8e..9173dc112c2e9 100644
--- a/test/ClangImporter/attr-swift_name-errors.swift
+++ b/test/ClangImporter/attr-swift_name-errors.swift
@@ -1,5 +1,5 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -typecheck %s \
-// RUN:     -verify -verify-additional-file %S/Inputs/custom-modules/ConflictingNames.h -verify-ignore-unknown
+// RUN:     -verify -verify-ignore-unrelated -verify-additional-file %S/Inputs/custom-modules/ConflictingNames.h -verify-ignore-unknown
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/attr-swift_name.swift b/test/ClangImporter/attr-swift_name.swift
index aae82c80c9950..29361fe5e1041 100644
--- a/test/ClangImporter/attr-swift_name.swift
+++ b/test/ClangImporter/attr-swift_name.swift
@@ -20,19 +20,19 @@ func test(_ i: Int) {
   // We only see these five warnings because Clang can catch the other invalid
   // cases, and marks the attribute as invalid ahead of time.
   
-  // CHECK: warning: too few parameters in swift_name attribute (expected 2; got 1)
+  // CHECK: warning: too few parameters in swift_name attribute (expected 2; got 1) [#ClangDeclarationImport]
   // CHECK: + (instancetype)g:(id)x outParam:(int *)foo SWIFT_NAME(init(g:));
   // CHECK-NOT: warning:
   // CHECK: note: please report this issue to the owners of 'ObjCIRExtras'
   // CHECK-NOT: warning:
 
-  // CHECK: warning: cycle detected while resolving 'CircularName' in swift_name attribute for 'CircularName'
+  // CHECK: warning: cycle detected while resolving 'CircularName' in swift_name attribute for 'CircularName' [#ClangDeclarationImport]
   // CHECK: SWIFT_NAME(CircularName.Inner) @interface CircularName : NSObject @end
   // CHECK-NOT: {{warning|note}}:
   // CHECK: note: please report this issue to the owners of 'ObjCIRExtras'
   // CHECK-NOT: warning:
 
-  // CHECK: warning: cycle detected while resolving 'MutuallyCircularNameB' in swift_name attribute for 'MutuallyCircularNameA'
+  // CHECK: warning: cycle detected while resolving 'MutuallyCircularNameB' in swift_name attribute for 'MutuallyCircularNameA' [#ClangDeclarationImport]
   // CHECK: SWIFT_NAME(MutuallyCircularNameB.Inner) @interface MutuallyCircularNameA : NSObject @end
   // CHECK-NOT: {{warning|note}}:
   // CHECK: note: while resolving 'MutuallyCircularNameA' in swift_name attribute for 'MutuallyCircularNameB'
diff --git a/test/ClangImporter/attr-swift_name_renaming-objc.swift b/test/ClangImporter/attr-swift_name_renaming-objc.swift
index 6a264271f7a5c..528727e2a7f3e 100644
--- a/test/ClangImporter/attr-swift_name_renaming-objc.swift
+++ b/test/ClangImporter/attr-swift_name_renaming-objc.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -I %/S/Inputs/custom-modules -Xcc -w -typecheck -verify %s -verify-additional-file %/S/Inputs/custom-modules%{fs-sep}SwiftName.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -I %/S/Inputs/custom-modules -Xcc -w -typecheck -verify -verify-ignore-unrelated %s -verify-additional-file %/S/Inputs/custom-modules%{fs-sep}SwiftName.h
 
 import SwiftName
 
diff --git a/test/ClangImporter/attr-swift_name_renaming.swift b/test/ClangImporter/attr-swift_name_renaming.swift
index b2bcb37173b3a..b02015ef6db17 100644
--- a/test/ClangImporter/attr-swift_name_renaming.swift
+++ b/test/ClangImporter/attr-swift_name_renaming.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -Xcc -w -typecheck -verify %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -Xcc -w -typecheck -verify -verify-ignore-unrelated %s
 
 import SwiftName
 
diff --git a/test/ClangImporter/attr-swift_private.swift b/test/ClangImporter/attr-swift_private.swift
index fd9af2910913f..87cacdc55be67 100644
--- a/test/ClangImporter/attr-swift_private.swift
+++ b/test/ClangImporter/attr-swift_private.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %build-clang-importer-objc-overlays
 
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -I %S/Inputs/custom-modules -typecheck %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -I %S/Inputs/custom-modules -typecheck %s -verify -verify-ignore-unrelated
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -I %S/Inputs/custom-modules -emit-ir %s -D IRGEN | %FileCheck %s
 
 // RUN: %target-swift-ide-test(mock-sdk: %clang-importer-sdk-nosource -I %t) -I %S/Inputs/custom-modules -print-module -source-filename="%s" -module-to-print SwiftPrivateAttr > %t.txt
diff --git a/test/ClangImporter/availability.swift b/test/ClangImporter/availability.swift
index b47fccad51230..4a55fc07e4db2 100644
--- a/test/ClangImporter/availability.swift
+++ b/test/ClangImporter/availability.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules %s -verify-ignore-unknown
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules %s -verify-ignore-unknown
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/availability_app_extension.swift b/test/ClangImporter/availability_app_extension.swift
index 2408c0ea7a257..3472f1c4508bc 100644
--- a/test/ClangImporter/availability_app_extension.swift
+++ b/test/ClangImporter/availability_app_extension.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -application-extension %s
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -application-extension-library %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -application-extension %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -application-extension-library %s
 
 // Check the exact error message, which requires a regex match
 // RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -application-extension %s 2>&1 | %FileCheck %s
diff --git a/test/ClangImporter/availability_custom_domains.swift b/test/ClangImporter/availability_custom_domains.swift
index 377e98a7a95f7..b5d777c120022 100644
--- a/test/ClangImporter/availability_custom_domains.swift
+++ b/test/ClangImporter/availability_custom_domains.swift
@@ -1,22 +1,36 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify \
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated \
 // RUN:   -import-objc-header %S/Inputs/availability_domains_bridging_header.h \
-// RUN:   -I %S/Inputs/custom-modules/availability-domains \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   %s %S/Inputs/availability_custom_domains_other.swift
+
+// Re-test with the bridging header precompiled into a .pch.
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-pch \
+// RUN:   -o %t/bridging-header.pch %S/Inputs/availability_domains_bridging_header.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated \
+// RUN:   -import-objc-header %t/bridging-header.pch \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
 // RUN:   -enable-experimental-feature CustomAvailability \
 // RUN:   %s %S/Inputs/availability_custom_domains_other.swift
 
 // REQUIRES: swift_feature_CustomAvailability
-// UNSUPPORTED: OS=windows-msvc
 
 // https://github.com/swiftlang/swift/issues/80058
 // UNSUPPORTED: OS=linux-android
 
 import Oceans // re-exports Rivers
 
-func testClangDecls() {
+func testClangDecls() { // expected-note 3 {{add '@available' attribute to enclosing global function}}
   available_in_arctic() // expected-error {{'available_in_arctic()' is only available in Arctic}}
+  // expected-note@-1 {{add 'if #available' version check}}
   unavailable_in_pacific() // expected-error {{'unavailable_in_pacific()' is unavailable}}
   available_in_colorado_river_delta() // expected-error {{'available_in_colorado_river_delta()' is only available in Pacific}}
+  // expected-note@-1 {{add 'if #available' version check}}
   available_in_colorado() // expected-error {{'available_in_colorado()' is only available in Colorado}}
+  // expected-note@-1 {{add 'if #available' version check}}
   available_in_baltic() // expected-error {{cannot find 'available_in_baltic' in scope}}
 }
 
@@ -33,15 +47,18 @@ func availableInPacific() { }
 func unavailableInColorado() { } // expected-note {{'unavailableInColorado()' has been explicitly marked unavailable here}}
 
 // The Seas module is only imported directly by the other source file.
-@available(Baltic) // expected-warning {{unrecognized platform name 'Baltic'}}
+@available(Baltic) // expected-error {{unrecognized platform name 'Baltic'}}
 func availableInBaltic() { } // expected-note {{did you mean 'availableInBaltic'}}
 
-func testSwiftDecls() {
+func testSwiftDecls() { // expected-note 3 {{add '@available' attribute to enclosing global function}}
   availableInBayBridge() // expected-error {{'availableInBayBridge()' is only available in BayBridge}}
+  // expected-note@-1 {{add 'if #available' version check}}
   unavailableInBayBridge() // expected-error {{'unavailableInBayBridge()' is unavailable}}
   availableInArctic()
   availableInPacific() // expected-error {{'availableInPacific()' is only available in Pacific}}
+  // expected-note@-1 {{add 'if #available' version check}}
   unavailableInColorado() // expected-error {{'unavailableInColorado()' is unavailable}}
   availableInBaltic()
   availableInMediterranean() // expected-error {{'availableInMediterranean()' is only available in Mediterranean}}
+  // expected-note@-1 {{add 'if #available' version check}}
 }
diff --git a/test/ClangImporter/availability_custom_domains_access_availability.swift b/test/ClangImporter/availability_custom_domains_access_availability.swift
new file mode 100644
index 0000000000000..8aba570eea1aa
--- /dev/null
+++ b/test/ClangImporter/availability_custom_domains_access_availability.swift
@@ -0,0 +1,444 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated \
+// RUN:   -import-objc-header %S/Inputs/availability_domains_bridging_header.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -experimental-spi-only-imports -parse-as-library -swift-version 4 \
+// RUN:   %s
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated \
+// RUN:   -import-objc-header %S/Inputs/availability_domains_bridging_header.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -experimental-spi-only-imports -parse-as-library -swift-version 5 \
+// RUN:   %s -verify-additional-prefix swift5-
+
+// REQUIRES: swift_feature_CustomAvailability
+
+private import Rivers // also re-exported by Oceans
+internal import Oceans
+// expected-note@-1 23 {{availability domain 'Arctic' imported as 'internal' from 'Oceans' here}}
+// expected-swift5-note@-2 2 {{availability domain 'Arctic' imported as 'internal' from 'Oceans' here}}
+// expected-note@-3 24 {{availability domain 'Colorado' imported as 'internal' from 'Oceans' here}}
+// expected-swift5-note@-4 2 {{availability domain 'Colorado' imported as 'internal' from 'Oceans' here}}
+// expected-note@-5 23 {{availability domain 'Grand' imported as 'internal' from 'Oceans' here}}
+// expected-swift5-note@-6 2 {{availability domain 'Grand' imported as 'internal' from 'Oceans' here}}
+public import Seas
+@_spiOnly import Lakes
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public global function 'publicFunc()'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public global function 'publicFunc()'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public global function 'publicFunc()'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+public func publicFunc() { }
+
+@available(Colorado) // expected-swift5-error {{availability domain 'Colorado' used in '@available' on global function 'usableFromInlineFunc()' must be '@usableFromInline' or public}}
+@available(Grand) // expected-swift5-error {{availability domain 'Grand' used in '@available' on global function 'usableFromInlineFunc()' must be '@usableFromInline' or public}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-swift5-error {{availability domain 'Arctic' used in '@available' on global function 'usableFromInlineFunc()' must be '@usableFromInline' or public}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+@usableFromInline func usableFromInlineFunc() { }
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public global function 'spiFunc()'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public global function 'spiFunc()'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public global function 'spiFunc()'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt)
+@_spi(Private) public func spiFunc() { }
+
+@available(Colorado)
+@available(Grand) // expected-warning {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic)
+@available(Baltic)
+@available(BayBridge)
+@available(Salt)
+func internalFunc() { }
+
+@available(Colorado)
+@available(Grand) // expected-warning {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic)
+@available(Baltic)
+@available(BayBridge)
+@available(Salt)
+private func privateFunc() { }
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public var 'publicGlobalVar'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public var 'publicGlobalVar'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public var 'publicGlobalVar'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+public var publicGlobalVar: Int {
+  get { 0 }
+  set { }
+}
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public struct 'PublicStruct'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public struct 'PublicStruct'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public struct 'PublicStruct'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+public struct PublicStruct { }
+
+public struct PublicGenericStruct<T> {
+  var value: T
+
+  @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public initializer 'init(value:)'}}
+  @available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public initializer 'init(value:)'}}
+  // expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  @available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public initializer 'init(value:)'}}
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+  public init(value: T) {
+    self.value = value
+  }
+
+  @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public property 'publicProperty'}}
+  @available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public property 'publicProperty'}}
+  // expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  @available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public property 'publicProperty'}}
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+  public var publicProperty: T { value }
+
+  @available(Colorado) // expected-swift5-error {{availability domain 'Colorado' used in '@available' on property 'usableFromInlineProperty' must be '@usableFromInline' or public}}
+  @available(Grand) // expected-swift5-error {{availability domain 'Grand' used in '@available' on property 'usableFromInlineProperty' must be '@usableFromInline' or public}}
+  // expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  @available(Arctic) // expected-swift5-error {{availability domain 'Arctic' used in '@available' on property 'usableFromInlineProperty' must be '@usableFromInline' or public}}
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+  @usableFromInline var usableFromInlineProperty: T { value }
+
+  public var publicPropertyWithSetter: T {
+    get { value }
+
+    @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public setter for property 'publicPropertyWithSetter'}}
+    @available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public setter for property 'publicPropertyWithSetter'}}
+    // expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+    @available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public setter for property 'publicPropertyWithSetter'}}
+    @available(Baltic)
+    @available(BayBridge)
+    @available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+    set { value = newValue }
+  }
+
+  @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public instance method 'publicMethod()'}}
+  @available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public instance method 'publicMethod()'}}
+  // expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  @available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public instance method 'publicMethod()'}}
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+  public func publicMethod() { }
+
+  @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public subscript 'subscript(_:)'}}
+  @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public subscript 'subscript(_:)'}}
+  @available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public subscript 'subscript(_:)'}}
+  // expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  @available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public subscript 'subscript(_:)'}}
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+  public subscript(indexForSubscriptInColorado: T) -> T { value }
+}
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public enum 'PublicEnum'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public enum 'PublicEnum'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public enum 'PublicEnum'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+public enum PublicEnum { }
+
+public enum PublicEnumWithCase {
+  @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public enum case 'colorado'}}
+  @available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public enum case 'colorado'}}
+  // expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  @available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public enum case 'colorado'}}
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+  case colorado
+}
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public class 'PublicClass'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public class 'PublicClass'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public class 'PublicClass'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+public class PublicClass { }
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public protocol 'PublicProtocol'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public protocol 'PublicProtocol'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public protocol 'PublicProtocol'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+public protocol PublicProtocol { }
+
+public protocol PublicProtocolWithAssociatedType {
+  @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public associated type 'AssociatedType'}}
+  @available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public associated type 'AssociatedType'}}
+  // expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  @available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public associated type 'AssociatedType'}}
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+  associatedtype AssociatedType
+
+  @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public instance method 'requirement()'}}
+  @available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public instance method 'requirement()'}}
+  // expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  @available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public instance method 'requirement()'}}
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+  func requirement() -> AssociatedType
+}
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public type alias 'PublicTypealias'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public type alias 'PublicTypealias'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public type alias 'PublicTypealias'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+public typealias PublicTypealias = Int
+
+@available(Colorado)
+@available(Grand) // expected-warning {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic)
+@available(Baltic)
+@available(BayBridge)
+@available(Salt)
+extension PublicGenericStruct { }
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public extension of generic struct 'PublicGenericStruct'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public extension of generic struct 'PublicGenericStruct'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public extension of generic struct 'PublicGenericStruct'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt)
+public extension PublicGenericStruct { }
+
+@available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be used in '@available' on public extension of generic struct 'PublicGenericStruct'}}
+@available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be used in '@available' on public extension of generic struct 'PublicGenericStruct'}}
+// expected-warning@-1 {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be used in '@available' on public extension of generic struct 'PublicGenericStruct'}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+public extension PublicGenericStruct {
+  func publicMemberOfPublicExtension() { }
+}
+
+@available(Colorado)
+@available(Grand) // expected-warning {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic)
+@available(Baltic)
+@available(BayBridge)
+@available(Salt)
+extension PublicGenericStruct {
+  func internalMethodInExtensionInColorado() { }
+}
+
+@available(Colorado) // expected-error {{cannot use availability domain 'Colorado' in an '@available' attribute here; 'Rivers' was not imported publicly}}
+@available(Grand) // expected-error {{cannot use availability domain 'Grand' in an '@available' attribute here; 'Rivers' was not imported publicly}}
+@available(Arctic) // expected-error {{cannot use availability domain 'Arctic' in an '@available' attribute here; 'Oceans' was not imported publicly}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+extension PublicGenericStruct {
+  public func publicMethodInExtensionInColorado() { }
+}
+
+@available(Colorado)
+@available(Grand) // expected-warning {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+@available(Arctic)
+@available(Baltic)
+@available(BayBridge)
+@available(Salt)
+extension PublicGenericStruct where T: PublicProtocolWithAssociatedType { }
+
+@available(Colorado) // expected-error {{cannot use availability domain 'Colorado' in an '@available' attribute here; 'Rivers' was not imported publicly}}
+@available(Grand) // expected-error {{cannot use availability domain 'Grand' in an '@available' attribute here; 'Rivers' was not imported publicly}}
+@available(Arctic) // expected-error {{cannot use availability domain 'Arctic' in an '@available' attribute here; 'Oceans' was not imported publicly}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+extension PublicGenericStruct: PublicProtocol {}
+
+@available(Colorado) // expected-error {{cannot use availability domain 'Colorado' in an '@available' attribute here; 'Rivers' was not imported publicly}}
+@available(Grand) // expected-error {{cannot use availability domain 'Grand' in an '@available' attribute here; 'Rivers' was not imported publicly}}
+@available(Arctic) // expected-error {{cannot use availability domain 'Arctic' in an '@available' attribute here; 'Oceans' was not imported publicly}}
+@available(Baltic)
+@available(BayBridge)
+@available(Salt) // expected-error {{cannot use availability domain 'Salt' in an '@available' attribute here; 'Lakes' was imported for SPI only}}
+extension PublicGenericStruct: PublicProtocolWithAssociatedType {
+  public func requirement() -> Int { 0 }
+}
+
+@inlinable public func inlinableFunc() {
+  if #available(Colorado) { } // expected-error {{availability domain 'Colorado' is internal and cannot be referenced from an '@inlinable' function}}
+  if #available(Grand) { } // expected-error {{availability domain 'Grand' is internal and cannot be referenced from an '@inlinable' function}}
+  if #available(Arctic) { } // expected-error {{availability domain 'Arctic' is internal and cannot be referenced from an '@inlinable' function}}
+  if #available(Baltic) { }
+  if #available(BayBridge) { }
+  if #available(Salt) { } // expected-error {{availability domain 'Salt' cannot be used in an '@inlinable' function because 'Lakes' was imported for SPI only}}
+  if #available(Aral) { } // expected-warning {{availability domain 'Aral' is deprecated}}
+  // expected-warning@-1 {{unnecessary check for 'Aral'; this condition will always be true}}
+  // expected-warning@-2 {{'if' condition is always true}}
+
+  @available(Colorado) // expected-error {{availability domain 'Colorado' is internal and cannot be referenced from an '@inlinable' function}}
+  @available(Grand) // expected-error {{availability domain 'Grand' is internal and cannot be referenced from an '@inlinable' function}}
+  @available(Arctic) // expected-error {{availability domain 'Arctic' is internal and cannot be referenced from an '@inlinable' function}}
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt) // expected-error {{availability domain 'Salt' cannot be used in an '@inlinable' function because 'Lakes' was imported for SPI only}}
+  @available(Aral) // expected-warning {{availability domain 'Aral' is deprecated}}
+  // expected-warning@-1 {{'@available' has no effect because 'Aral' is always available}}{{3-20=}}
+  func nestedFunc() { }
+}
+
+public func nonInlinablePublicFunc() {
+  if #available(Colorado) { }
+  if #available(Grand) { } // expected-warning {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  if #available(Arctic) { }
+  if #available(Baltic) { }
+  if #available(BayBridge) { }
+  if #available(Salt) { }
+  if #available(Aral) { } // expected-warning {{availability domain 'Aral' is deprecated}}
+  // expected-warning@-1 {{unnecessary check for 'Aral'; this condition will always be true}}
+  // expected-warning@-2 {{'if' condition is always true}}
+
+  @available(Colorado)
+  @available(Grand) // expected-warning {{availability domain 'Grand' is deprecated: Use Colorado instead}}
+  @available(Arctic)
+  @available(Baltic)
+  @available(BayBridge)
+  @available(Salt)
+  @available(Aral) // expected-warning {{availability domain 'Aral' is deprecated}}
+  // expected-warning@-1 {{'@available' has no effect because 'Aral' is always available}}{{3-20=}}
+  func nestedFunc() { }
+}
+
+@available(Aral) // expected-warning {{availability domain 'Aral' is deprecated}}
+// expected-warning@-1 {{'@available' has no effect because 'Aral' is always available}}{{1-18=}}
+func testPermanentlyAvailable() { }
+
+@available(Aral, deprecated)
+// expected-warning@-1 {{'Aral' is always available, use '*' instead}}{{12-16=*}}
+func testPermanentlyDeprecated() { }
+
+@available(Aral, unavailable) // expected-warning {{availability domain 'Aral' is deprecated}}
+// expected-warning@-1 {{'Aral' is always available, use '*' instead}}{{12-16=*}}
+func testPermanentlyUnavailable() { }
+
+@available(*, deprecated)
+extension PublicGenericStruct {
+  @available(Aral)
+  // expected-warning@-1 {{'@available' has no effect because 'Aral' is always available}}{{3-19=}}
+  func testPermanentlyAvailableInDeprecatedExtension() { }
+
+  @available(Aral, deprecated)
+  // expected-warning@-1 {{'Aral' is always available, use '*' instead}}{{14-18=*}}
+  func testPermanentlyDeprecatedInDeprecatedExtension() { }
+
+  @available(Aral, unavailable)
+  // expected-warning@-1 {{'Aral' is always available, use '*' instead}}{{14-18=*}}
+  func testPermanentlyUnavailableInDeprecatedExtension() { }
+}
+
+@available(*, unavailable)
+extension PublicGenericStruct {
+  @available(Aral) // expected-warning {{availability domain 'Aral' is deprecated}}
+  // expected-warning@-1 {{'@available' has no effect because 'Aral' is always available}}{{3-20=}}
+  func testPermanentlyAvailableInUnavailableExtension() { }
+
+  @available(Aral, deprecated)
+  // expected-warning@-1 {{'Aral' is always available, use '*' instead}}{{14-18=*}}
+  func testPermanentlyDeprecatedInUnavailableExtension() { }
+
+  @available(Aral, unavailable) // expected-warning {{availability domain 'Aral' is deprecated}}
+  // expected-warning@-1 {{'Aral' is always available, use '*' instead}}{{14-18=*}}
+  func testPermanentlyUnavailableInUnavailableExtension() { }
+}
+
+func testUnnecessaryIfAvailableStmt() {
+  if #available(Aral) {
+    // expected-warning@-1 {{availability domain 'Aral' is deprecated}}
+    // expected-warning@-2 {{unnecessary check for 'Aral'; this condition will always be true}}{{none}}
+    // expected-warning@-3 {{'if' condition is always true}}{{none}}
+  }
+}
+
+func testUnnecessaryIfAvailableExpr() {
+  _ = if #available(Aral) { true } else { false }
+  // expected-warning@-1 {{availability domain 'Aral' is deprecated}}
+  // FIXME: [availability] Missing "always true" diagnostic
+  // https://github.com/swiftlang/swift/issues/84453
+}
+
+func testUnnecessaryIfAvailableCompoundStmt() {
+  if #available(Colorado), #available(Aral) {
+    // expected-warning@-1 {{availability domain 'Aral' is deprecated}}
+    // expected-warning@-2 {{unnecessary check for 'Aral'; this condition will always be true}}{{none}}
+  }
+}
+
+func testUnnecessaryIfUnavailableStmt() {
+  if #unavailable(Aral) {
+    // expected-warning@-1 {{availability domain 'Aral' is deprecated}}
+    // expected-warning@-2 {{unnecessary check for 'Aral'; this condition will always be false}}{{none}}
+  }
+}
+
+func testUnnecessaryIfUnavailableCompoundStmt() {
+  if #unavailable(Colorado), #unavailable(Aral) {
+    // expected-warning@-1 {{availability domain 'Aral' is deprecated}}
+    // expected-warning@-2 {{unnecessary check for 'Aral'; this condition will always be false}}{{none}}
+  }
+}
+
+func testUnnecessaryGuardAvailableStmt() {
+  guard #available(Aral) else {
+    // expected-warning@-1 {{availability domain 'Aral' is deprecated}}
+    // expected-warning@-2 {{unnecessary check for 'Aral'; this condition will always be true}}{{none}}
+    // expected-warning@-3 {{'guard' condition is always true}}{{none}}
+    return
+  }
+}
+
+func testUnnecessaryGuardUnavailableStmt() {
+  guard #unavailable(Aral) else {
+    // expected-warning@-1 {{availability domain 'Aral' is deprecated}}
+    // expected-warning@-2 {{unnecessary check for 'Aral'; this condition will always be false}}{{none}}
+    return
+  }
+}
+
+func testUnnecessaryWhileAvailableStmt() {
+  while #available(Aral) {
+    // expected-warning@-1 {{availability domain 'Aral' is deprecated}}
+    // expected-warning@-2 {{unnecessary check for 'Aral'; this condition will always be true}}{{none}}
+    // expected-warning@-3 {{'while' condition is always true}}{{none}}
+    break
+  }
+}
diff --git a/test/ClangImporter/availability_custom_domains_objc.swift b/test/ClangImporter/availability_custom_domains_objc.swift
new file mode 100644
index 0000000000000..a55c898025127
--- /dev/null
+++ b/test/ClangImporter/availability_custom_domains_objc.swift
@@ -0,0 +1,80 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated \
+// RUN:   -import-objc-header %S/Inputs/availability_domains_bridging_header.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   %s %S/Inputs/availability_custom_domains_other.swift
+
+// Re-test with the bridging header precompiled into a .pch.
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-pch \
+// RUN:   -o %t/bridging-header.pch %S/Inputs/availability_domains_bridging_header.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated \
+// RUN:   -import-objc-header %t/bridging-header.pch \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   %s %S/Inputs/availability_custom_domains_other.swift
+
+// REQUIRES: swift_feature_CustomAvailability
+// REQUIRES: objc_interop
+
+import Oceans // re-exports Rivers
+
+func testObjCClasses( // expected-note {{add '@available' attribute to enclosing global function}}
+  _ bayBridgeAvailable: BayBridgeAvailable, // expected-error {{'BayBridgeAvailable' is only available in BayBridge}}
+  _ bayBridgeUnavailable: BayBridgeUnavailable, // expected-error {{'BayBridgeUnavailable' is unavailable}}
+) { }
+
+@objc @implementation
+extension ImplementMe {
+  // FIXME: [availability] @available(BayBridge) should be required
+  func availableInBayBridge() { }
+
+  // FIXME: [availability] Should match and suggest @available(BayBridge, unavailable)
+  func unavailableInBayBridge() { } // expected-error {{instance method 'unavailableInBayBridge()' does not match any instance method declared in the headers for 'ImplementMe'}}
+  // expected-note@-1 {{add 'private' or 'fileprivate'}}
+  // expected-note@-2 {{add 'final' to define a Swift-only instance method}}
+
+  @available(GoldenGateBridge)
+  func availableInGoldenGateBridge() { }
+
+  // FIXME: [availability] This should be accepted
+  @available(GoldenGateBridge, unavailable)
+  func unavailableInGoldenGateBridge() { } // expected-error {{instance method 'unavailableInGoldenGateBridge()' does not match any instance method declared in the headers for 'ImplementMe'}}
+  // expected-note@-1 {{add 'private' or 'fileprivate'}}
+  // expected-note@-2 {{add 'final' to define a Swift-only instance method}}
+}
+
+@objc @implementation
+extension ImplementMeBayBridgeAvailable { // expected-error {{'ImplementMeBayBridgeAvailable' is only available in BayBridge}}
+  // expected-note@-1 {{add '@available' attribute to enclosing extension}}
+}
+
+@objc @implementation
+extension ImplementMeBayBridgeUnavailable { // expected-error {{'ImplementMeBayBridgeUnavailable' is unavailable}}
+}
+
+@available(GoldenGateBridge)
+@objc @implementation
+extension ImplementMeGoldenGateBridgeAvailable {
+}
+
+@available(BayBridge)
+@objc @implementation
+extension ImplementMeGoldenGateBridgeAvailable2 { // expected-error {{'ImplementMeGoldenGateBridgeAvailable2' is only available in GoldenGateBridge}}
+  // expected-note@-1 {{add '@available' attribute to enclosing extension}}
+}
+
+// FIXME: [availability] This implementation should be rejected because its less
+// available than the original class declaration.
+@available(BayBridge)
+@available(GoldenGateBridge)
+@objc @implementation
+extension ImplementMeGoldenGateBridgeAvailable3 {
+}
+
+@available(GoldenGateBridge, unavailable)
+@objc @implementation
+extension ImplementMeGoldenGateBridgeUnavailable {
+}
diff --git a/test/ClangImporter/availability_ios.swift b/test/ClangImporter/availability_ios.swift
index 90f784202f559..76d054675efd2 100644
--- a/test/ClangImporter/availability_ios.swift
+++ b/test/ClangImporter/availability_ios.swift
@@ -1,6 +1,6 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules %s
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules -application-extension %s
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules -application-extension-library %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules -application-extension %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules -application-extension-library %s
 
 // REQUIRES: OS=ios
 
diff --git a/test/ClangImporter/availability_macosx.swift b/test/ClangImporter/availability_macosx.swift
index 857a0a39fd29a..1eeb56445b44a 100644
--- a/test/ClangImporter/availability_macosx.swift
+++ b/test/ClangImporter/availability_macosx.swift
@@ -1,6 +1,6 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules %s
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules -application-extension %s
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules -application-extension-library %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules -application-extension %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules -application-extension-library %s
 
 // REQUIRES: OS=macosx
 
@@ -29,7 +29,7 @@ func bezierPathElementToInteger(_ e: NSBezierPathElement) -> Int {
 }
 
 func integerToBezierPathElement(_ i: Int) -> NSBezierPathElement {
-  // expected-note@-1 2 {{add @available attribute to enclosing global function}}
+  // expected-note@-1 2 {{add '@available' attribute to enclosing global function}}
   switch i {
   case 1:
     return .moveTo
diff --git a/test/ClangImporter/availability_macosx_canonical_versions.swift b/test/ClangImporter/availability_macosx_canonical_versions.swift
index da2d8d3ab0fd5..b777eba211024 100644
--- a/test/ClangImporter/availability_macosx_canonical_versions.swift
+++ b/test/ClangImporter/availability_macosx_canonical_versions.swift
@@ -11,3 +11,11 @@ FunctionIntroducedIn10_16()
 FunctionIntroducedIn11_0()
 // expected-error@-1 {{'FunctionIntroducedIn11_0()' is only available in macOS 11.0 or newer}}
 // expected-note@-2 {{add 'if #available' version check}}
+
+FunctionIntroducedIn16_0()
+// expected-error@-1 {{'FunctionIntroducedIn16_0()' is only available in macOS 26.0 or newer}}
+// expected-note@-2 {{add 'if #available' version check}}
+
+FunctionIntroducedIn26_0()
+// expected-error@-1 {{'FunctionIntroducedIn26_0()' is only available in macOS 26.0 or newer}}
+// expected-note@-2 {{add 'if #available' version check}}
diff --git a/test/ClangImporter/availability_macosx_canonical_versions_appext.swift b/test/ClangImporter/availability_macosx_canonical_versions_appext.swift
index e0d655164debc..37d5bb51a1588 100644
--- a/test/ClangImporter/availability_macosx_canonical_versions_appext.swift
+++ b/test/ClangImporter/availability_macosx_canonical_versions_appext.swift
@@ -11,3 +11,11 @@ FunctionIntroducedIn10_16AppExt()
 FunctionIntroducedIn11_0AppExt()
 // expected-error@-1 {{'FunctionIntroducedIn11_0AppExt()' is only available in application extensions for macOS 11.0 or newer}}
 // expected-note@-2 {{add 'if #available' version check}}
+
+FunctionIntroducedIn16_0AppExt()
+// expected-error@-1 {{'FunctionIntroducedIn16_0AppExt()' is only available in application extensions for macOS 26.0 or newer}}
+// expected-note@-2 {{add 'if #available' version check}}
+
+FunctionIntroducedIn26_0AppExt()
+// expected-error@-1 {{'FunctionIntroducedIn26_0AppExt()' is only available in application extensions for macOS 26.0 or newer}}
+// expected-note@-2 {{add 'if #available' version check}}
diff --git a/test/ClangImporter/availability_returns_twice-msvc-x86_64.swift b/test/ClangImporter/availability_returns_twice-msvc-x86_64.swift
index ee2443bed80ae..07ce5e7dea3de 100644
--- a/test/ClangImporter/availability_returns_twice-msvc-x86_64.swift
+++ b/test/ClangImporter/availability_returns_twice-msvc-x86_64.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 // REQUIRES: OS=windows-msvc && CPU=x86_64
 
 import vcruntime
diff --git a/test/ClangImporter/availability_returns_twice.swift b/test/ClangImporter/availability_returns_twice.swift
index 2df836ca38d2d..65bfd8d92a006 100644
--- a/test/ClangImporter/availability_returns_twice.swift
+++ b/test/ClangImporter/availability_returns_twice.swift
@@ -1,9 +1,9 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // UNSUPPORTED: OS=windows-msvc
 
 // `setjmp` is not available on WebAssembly/WASI
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 // https://github.com/apple/swift/issues/51632
 // In Android jmp_buf is int[16], which doesn't convert to &Int
@@ -11,7 +11,10 @@
 // XFAIL: OS=linux-android
 // XFAIL: OS=openbsd
 
-#if canImport(Darwin)
+#if canImport(setjmp_h)
+  import setjmp_h
+  typealias JumpBuffer = Int32
+#elseif canImport(Darwin)
   import Darwin
   typealias JumpBuffer = Int32
 #elseif canImport(Glibc)
diff --git a/test/ClangImporter/availability_spi_as_unavailable.swift b/test/ClangImporter/availability_spi_as_unavailable.swift
index 16af331729c47..7affc3ea9d5e9 100644
--- a/test/ClangImporter/availability_spi_as_unavailable.swift
+++ b/test/ClangImporter/availability_spi_as_unavailable.swift
@@ -1,6 +1,6 @@
 // REQUIRES: OS=macosx
-// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify -DNOT_UNDERLYING -library-level api -parse-as-library -require-explicit-availability=ignore
-// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -module-name SPIContainer -import-underlying-module -verify -library-level api -parse-as-library  -require-explicit-availability=ignore
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify -verify-ignore-unrelated -DNOT_UNDERLYING -library-level api -parse-as-library -require-explicit-availability=ignore
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -module-name SPIContainer -import-underlying-module -verify -verify-ignore-unrelated -library-level api -parse-as-library  -require-explicit-availability=ignore
 
 #if NOT_UNDERLYING
 import SPIContainer
diff --git a/test/ClangImporter/availability_spi_as_unavailable_bridging_header.swift b/test/ClangImporter/availability_spi_as_unavailable_bridging_header.swift
index d5936e09e5a43..f84d7118fc55b 100644
--- a/test/ClangImporter/availability_spi_as_unavailable_bridging_header.swift
+++ b/test/ClangImporter/availability_spi_as_unavailable_bridging_header.swift
@@ -1,5 +1,5 @@
 // REQUIRES: OS=macosx
-// RUN: %target-swift-frontend -typecheck %s -import-objc-header %S/Inputs/frameworks/SPIContainer.framework/Headers/SPIContainer.h -verify -library-level api
+// RUN: %target-swift-frontend -typecheck %s -import-objc-header %S/Inputs/frameworks/SPIContainer.framework/Headers/SPIContainer.h -verify -verify-ignore-unrelated -library-level api
 
 
 @_spi(a) public let a: SPIInterface1
diff --git a/test/ClangImporter/availability_spi_transitive.swift b/test/ClangImporter/availability_spi_transitive.swift
index d704d2ba4dec2..397a981e111f8 100644
--- a/test/ClangImporter/availability_spi_transitive.swift
+++ b/test/ClangImporter/availability_spi_transitive.swift
@@ -1,5 +1,5 @@
 // REQUIRES: OS=macosx
-// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify -library-level api
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify -verify-ignore-unrelated -library-level api
 
 import SPIContainerImporter
 
diff --git a/test/ClangImporter/availability_variadic.swift b/test/ClangImporter/availability_variadic.swift
index 7070f8467f33d..a6d6f80842d42 100644
--- a/test/ClangImporter/availability_variadic.swift
+++ b/test/ClangImporter/availability_variadic.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules %s
 
 // REQUIRES: OS=macosx
 
diff --git a/test/ClangImporter/availability_watchos.swift b/test/ClangImporter/availability_watchos.swift
index 2c898730b264e..1c45884356850 100644
--- a/test/ClangImporter/availability_watchos.swift
+++ b/test/ClangImporter/availability_watchos.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules %s
 
 // REQUIRES: OS=watchos
 
diff --git a/test/ClangImporter/bad-ns-extensible-string-enum.swift b/test/ClangImporter/bad-ns-extensible-string-enum.swift
index 8db500d44405a..b5cfddc0bf962 100644
--- a/test/ClangImporter/bad-ns-extensible-string-enum.swift
+++ b/test/ClangImporter/bad-ns-extensible-string-enum.swift
@@ -1,3 +1,3 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %s -enable-objc-interop -import-objc-header %S/Inputs/bad-ns-extensible-string-enum.h -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %s -enable-objc-interop -import-objc-header %S/Inputs/bad-ns-extensible-string-enum.h -verify -verify-ignore-unrelated
 
 let string = MyString.MyStringOne // expected-error {{cannot find 'MyString' in scope}}
diff --git a/test/ClangImporter/broken-modules.swift b/test/ClangImporter/broken-modules.swift
index 7ca1bda9e8ca6..288d59791787b 100644
--- a/test/ClangImporter/broken-modules.swift
+++ b/test/ClangImporter/broken-modules.swift
@@ -1,6 +1,6 @@
 // RUN: not %target-swift-frontend -typecheck %s -I %S/Inputs/custom-modules/ -enable-objc-interop -show-diagnostics-after-fatal -D MISSING_FROM_MODULE -o /dev/null 2>&1 | %FileCheck -check-prefix CHECK-MODULE-MAP %s
 // RUN: not %target-swift-frontend -typecheck %s -I %S/Inputs/custom-modules/ -enable-objc-interop -show-diagnostics-after-fatal -o /dev/null 2>&1 | %FileCheck -check-prefix CHECK -check-prefix CHECK-DIRECT %s
-// RUN: not %target-swift-frontend -typecheck %s -I %S/Inputs/custom-modules/ -enable-objc-interop -show-diagnostics-after-fatal -D INDIRECT -o /dev/null 2>&1 | %FileCheck -check-prefix CHECK -check-prefix CHECK-INDIRECT %s
+// RUN: not %target-swift-frontend -typecheck %s -I %S/Inputs/custom-modules/ -I %S/Inputs/custom-modules/more-custom-modules -enable-objc-interop -show-diagnostics-after-fatal -D INDIRECT -o /dev/null 2>&1 | %FileCheck -check-prefix CHECK -check-prefix CHECK-INDIRECT %s
 
 // FIXME: not every test here depends on Objective-C syntax, this test can be split.
 
diff --git a/test/ClangImporter/cf.swift b/test/ClangImporter/cf.swift
index c987303b5baca..90da57bc9e58a 100644
--- a/test/ClangImporter/cf.swift
+++ b/test/ClangImporter/cf.swift
@@ -1,6 +1,6 @@
-// RUN: %target-swift-frontend -disable-objc-attr-requires-foundation-module -typecheck -verify -import-cf-types -I %S/Inputs/custom-modules %s
+// RUN: %target-swift-frontend -disable-objc-attr-requires-foundation-module -typecheck -verify -verify-ignore-unrelated -import-cf-types -I %S/Inputs/custom-modules %s
 
-// RUN: %target-swift-frontend -disable-objc-attr-requires-foundation-module -typecheck -verify -import-cf-types -enable-experimental-cxx-interop -I %S/Inputs/custom-modules %s
+// RUN: %target-swift-frontend -disable-objc-attr-requires-foundation-module -typecheck -verify -verify-ignore-unrelated -import-cf-types -enable-experimental-cxx-interop -I %S/Inputs/custom-modules %s
 
 // REQUIRES: objc_interop
 
@@ -118,6 +118,7 @@ func testOutParametersGood() {
 func testOutParametersBad() {
   let fridge: CCRefrigerator?
   CCRefrigeratorCreateIndirect(fridge) // expected-error {{cannot convert value of type 'CCRefrigerator?' to expected argument type 'UnsafeMutablePointer<CCRefrigerator?>?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('CCRefrigerator' and 'UnsafeMutablePointer<CCRefrigerator?>') are expected to be equal}}
 
   let power: CCPowerSupply?
   CCRefrigeratorGetPowerSupplyIndirect(0, power)
@@ -128,13 +129,16 @@ func testOutParametersBad() {
   CCRefrigeratorGetItemUnaudited(0, 0, item)
   // expected-error@-1:34 {{cannot convert value of type 'Int' to expected argument type 'CCRefrigerator'}}
   // expected-error@-2:40 {{cannot convert value of type 'CCItem?' to expected argument type 'UnsafeMutablePointer<Unmanaged<CCItem>?>?'}}
+  // expected-note@-3 {{arguments to generic parameter 'Wrapped' ('CCItem' and 'UnsafeMutablePointer<Unmanaged<CCItem>?>') are expected to be equal}}
 }
 
 func nameCollisions() {
   var objc: MyProblematicObject?
   var cf: MyProblematicObjectRef?
   cf = objc // expected-error {{cannot assign value of type 'MyProblematicObject?' to type 'MyProblematicObjectRef?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('MyProblematicObject' and 'MyProblematicObjectRef') are expected to be equal}}
   objc = cf // expected-error {{cannot assign value of type 'MyProblematicObjectRef?' to type 'MyProblematicObject?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('MyProblematicObjectRef' and 'MyProblematicObject') are expected to be equal}}
 
   var cfAlias: MyProblematicAliasRef?
   cfAlias = cf // okay
@@ -142,7 +146,9 @@ func nameCollisions() {
 
   var otherAlias: MyProblematicAlias?
   otherAlias = cfAlias // expected-error {{cannot assign value of type 'MyProblematicAliasRef?' (aka 'Optional<MyProblematicObjectRef>') to type 'MyProblematicAlias?' (aka 'Optional<Float>')}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('MyProblematicAliasRef' (aka 'MyProblematicObjectRef') and 'MyProblematicAlias' (aka 'Float')) are expected to be equal}}
   cfAlias = otherAlias // expected-error {{cannot assign value of type 'MyProblematicAlias?' (aka 'Optional<Float>') to type 'MyProblematicAliasRef?' (aka 'Optional<MyProblematicObjectRef>')}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('MyProblematicAlias' (aka 'Float') and 'MyProblematicAliasRef' (aka 'MyProblematicObjectRef')) are expected to be equal}}
 
   func isOptionalFloat(_: inout Optional<Float>) {}
   isOptionalFloat(&otherAlias) // okay
@@ -161,11 +167,11 @@ func testNonConstVoid() {
 
 class NuclearFridge: CCRefrigerator {} // expected-error {{cannot inherit from Core Foundation type 'CCRefrigerator'}}
 extension CCRefrigerator {
-  @objc func foo() {} // expected-error {{method cannot be marked @objc because Core Foundation types are not classes in Objective-C}}
+  @objc func foo() {} // expected-error {{method cannot be marked '@objc' because Core Foundation types are not classes in Objective-C}}
   func bar() {} // okay, implicitly non-objc
 }
 
 protocol SwiftProto {}
 @objc protocol ObjCProto {}
-extension CCRefrigerator: ObjCProto {} // expected-error {{Core Foundation class 'CCRefrigerator' cannot conform to @objc protocol 'ObjCProto' because Core Foundation types are not classes in Objective-C}}
+extension CCRefrigerator: ObjCProto {} // expected-error {{Core Foundation class 'CCRefrigerator' cannot conform to '@objc' protocol 'ObjCProto' because Core Foundation types are not classes in Objective-C}}
 extension CCRefrigerator: SwiftProto {}
diff --git a/test/ClangImporter/cfuncs_parse.swift b/test/ClangImporter/cfuncs_parse.swift
index d5e4390da11b4..d91d9248868ab 100644
--- a/test/ClangImporter/cfuncs_parse.swift
+++ b/test/ClangImporter/cfuncs_parse.swift
@@ -1,5 +1,5 @@
 // XFAIL: CPU=powerpc64le
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs %s
 
 import cfuncs
 
@@ -68,9 +68,11 @@ func test_pow() {
 }
 
 // https://github.com/apple/swift/issues/51573
-// long doubles in AAPCS64 are 128 bits, which is not supported by
-// Swift, so don't test this.
-#if !((os(Android) || os(Linux)) && arch(arm64))
+// long doubles in AAPCS64 and 64-bit Android are 128 bits, which is not
+// supported by Swift, so don't test this.
+#if !((os(Android) && _pointerBitWidth(_64)) ||
+  (os(Linux) && arch(arm64)) ||
+  (os(FreeBSD) && arch(arm64)))
 func test_powl() {
   powl(1.5, 2.5)
 }
diff --git a/test/ClangImporter/const_values.swift b/test/ClangImporter/const_values.swift
new file mode 100644
index 0000000000000..b69627ed1c156
--- /dev/null
+++ b/test/ClangImporter/const_values.swift
@@ -0,0 +1,174 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %t/src/main.swift \
+// RUN:   -import-bridging-header %t/src/test.h \
+// RUN:   -module-name main -I %t -emit-sil -serialize-diagnostics -serialize-diagnostics-path %t/test.diag | %FileCheck %s
+
+// RUN: c-index-test -read-diagnostics %t/test.diag 2>&1 | %FileCheck --check-prefix CHECK-DIAG %t/src/test.h
+
+//--- test.h
+#include <stdbool.h>
+
+#define MACRO_INT 42
+
+const int const_int = 42;
+static int static_int = 42;
+static const int static_const_int = 42;
+
+static const bool static_const_bool = true;
+static const char static_const_char = 42;
+static const char static_const_char_with_long_literal = 42ull;
+static const char static_const_char_with_overflow_literal = 777ull; // CHECK-DIAG: [[@LINE]]:{{.*}}: warning: implicit conversion from 'unsigned long long' to 'char' changes value from 777 to 9
+static const long static_const_long = 42;
+static const float static_const_float = 42.0;
+static const double static_const_double = 42.0;
+
+static const char static_const_char_array[4] = {1, 2, 3, 4};
+static const char *static_const_pointer = 0;
+
+static const char static_const_char_referencing_other_const = 1 + static_const_char;
+
+typedef enum MyEnum: char {
+  MyEnumCase0 = 0, MyEnumCase1, MyEnumCase2
+} MyEnum;
+static const MyEnum static_const_enum = MyEnumCase1;
+
+struct MyStruct {
+  int field;
+};
+__attribute__((swift_name("MyStruct.static_const_int_as_a_member")))
+static const int static_const_int_as_a_member = 42;
+
+typedef int ImportAsStruct __attribute__((swift_wrapper(struct)));
+static const ImportAsStruct ImportAsStructFoo = 123;
+typedef int ImportAsEnum __attribute__((swift_wrapper(enum)));
+static const ImportAsEnum ImportAsEnumFoo = 123;
+
+//--- main.swift
+func foo() {
+  print(MACRO_INT)
+
+  print(const_int)
+  print(static_int)
+  print(static_const_int)
+
+  print(static_const_bool)
+  print(static_const_char)
+  print(static_const_char_with_long_literal)
+  print(static_const_char_with_overflow_literal)
+  print(static_const_long)
+  print(static_const_float)
+  print(static_const_double)
+
+  print(static_const_char_array)
+  print(static_const_pointer)
+
+  print(static_const_char_referencing_other_const)
+
+  print(static_const_enum)
+
+  print(MyStruct.static_const_int_as_a_member)
+
+  print(ImportAsStruct.foo)
+  print(ImportAsEnum.foo)
+}
+
+// Globals that don't get their value imported stay as public_external:
+// CHECK: sil_global public_external @static_int : $Int32
+// CHECK: sil_global public_external [let] @static_const_char_array : $(Int8, Int8, Int8, Int8)
+// CHECK: sil_global public_external @static_const_pointer : $Optional<UnsafePointer<Int8>>
+
+// CHECK:      sil shared [transparent] @$sSC9MACRO_INTs5Int32Vvg : $@convention(thin) () -> Int32 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int32, 42
+// CHECK-NEXT:   %1 = struct $Int32 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo9const_ints5Int32Vvg : $@convention(thin) () -> Int32 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int32, 42
+// CHECK-NEXT:   %1 = struct $Int32 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo16static_const_ints5Int32Vvg : $@convention(thin) () -> Int32 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int32, 42
+// CHECK-NEXT:   %1 = struct $Int32 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo17static_const_boolSbvg : $@convention(thin) () -> Bool {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int1, -1
+// CHECK-NEXT:   %1 = struct $Bool (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo17static_const_chars4Int8Vvg : $@convention(thin) () -> Int8 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int8, 42
+// CHECK-NEXT:   %1 = struct $Int8 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo35static_const_char_with_long_literals4Int8Vvg : $@convention(thin) () -> Int8 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int8, 42
+// CHECK-NEXT:   %1 = struct $Int8 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo39static_const_char_with_overflow_literals4Int8Vvg : $@convention(thin) () -> Int8 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int8, 9
+// CHECK-NEXT:   %1 = struct $Int8 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo17static_const_long{{.*}} : $@convention(thin) () -> {{.*}} {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal {{.*}}, 42
+// CHECK-NEXT:   %1 = struct {{.*}} (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo18static_const_floatSfvg : $@convention(thin) () -> Float {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = float_literal $Builtin.FPIEEE32, 0x42280000 // 42
+// CHECK-NEXT:   %1 = struct $Float (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo19static_const_doubleSdvg : $@convention(thin) () -> Double {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = float_literal $Builtin.FPIEEE64, 0x4045000000000000 // 42
+// CHECK-NEXT:   %1 = struct $Double (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo036static_const_char_referencing_other_B0s4Int8Vvg : $@convention(thin) () -> Int8 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int8, 43
+// CHECK-NEXT:   %1 = struct $Int8 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo17static_const_enumSo6MyEnumVvg : $@convention(thin) () -> MyEnum {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int8, 1
+// CHECK-NEXT:   %1 = struct $Int8 (%0)
+// CHECK-NEXT:   %2 = struct $MyEnum (%1)
+// CHECK-NEXT:   return %2
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo8MyStructV28static_const_int_as_a_members5Int32VvgZ : $@convention(method) (@thin MyStruct.Type) -> Int32 {
+// CHECK-NEXT: // %0 "self"
+// CHECK-NEXT: bb0(%0 : $@thin MyStruct.Type):
+// CHECK-NEXT:   debug_value %0, let, name "self", argno 1
+// CHECK-NEXT:   %2 = integer_literal $Builtin.Int32, 42
+// CHECK-NEXT:   %3 = struct $Int32 (%2)
+// CHECK-NEXT:   return %3
+// CHECK-NEXT: }
diff --git a/test/ClangImporter/const_values_apinotes.swift b/test/ClangImporter/const_values_apinotes.swift
new file mode 100644
index 0000000000000..d8b00bae165e4
--- /dev/null
+++ b/test/ClangImporter/const_values_apinotes.swift
@@ -0,0 +1,38 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %t/src/main.swift \
+// RUN:   -module-name main -I %t/src -emit-sil -sil-verify-all | %FileCheck %s
+
+//--- test.h
+
+typedef long NSInteger;
+typedef enum XCTestErrorCode: NSInteger {
+    XCTestErrorCodeTimeoutWhileWaiting,
+    XCTestErrorCodeFailureWhileWaiting,
+} XCTestErrorCode;
+
+static XCTestErrorCode const XCTestErrorUnsupported = (XCTestErrorCode)109;
+
+//--- Framework.apinotes
+---
+Name: Framework
+Tags:
+- Name: XCTestErrorCode
+  NSErrorDomain: XCTestErrorDomain
+
+//--- module.modulemap
+module Framework {
+  header "test.h"
+}
+
+//--- main.swift
+import Framework
+func foo() {
+  print(XCTestError.timeoutWhileWaiting)
+  print(XCTestErrorUnsupported)
+}
+
+
+// CHECK: // XCTestErrorUnsupported.getter
+// CHECK: sil shared [transparent] @$sSo22XCTestErrorUnsupportedSo0aB4CodeVvg : $@convention(thin) () -> XCTestError {
diff --git a/test/ClangImporter/const_values_cxx.swift b/test/ClangImporter/const_values_cxx.swift
new file mode 100644
index 0000000000000..e1a0c75502444
--- /dev/null
+++ b/test/ClangImporter/const_values_cxx.swift
@@ -0,0 +1,100 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+// RUN: %target-swiftxx-frontend %t/src/main.swift \
+// RUN:   -import-bridging-header %t/src/test.h \
+// RUN:   -module-name main -I %t -emit-sil | %FileCheck %s
+
+//--- test.h
+
+const int const_int = 42;
+namespace Namespace {
+  const int namespaced_const_int = 42;
+}
+
+static inline int foo() { return 42; }
+const int not_really_constant = foo();
+
+constexpr int constexpr_func() { return 42; }
+constexpr int constexpr_int = constexpr_func();
+static constexpr int static_constexpr_int = constexpr_func();
+
+class MyClass {
+public:
+  const int class_const_int = 42; // member field, don't expect to import as a global, no CHECKs for this
+  static const int class_static_const_int = 42;
+};
+
+namespace OtherNamespace {
+  constexpr int namespaced_constexpr_int = constexpr_func();
+  static constexpr int namespaced_static_constexpr_int = constexpr_func();
+}
+class OtherClass {
+  static constexpr int class_static_constexpr_int = 42;
+};
+
+template <int N, int M>
+inline const int template_gcd = template_gcd<M, N % M>;
+
+template <int N>
+inline const int template_gcd<N, 0> = N;
+
+
+//--- main.swift
+func foo() {
+  print(const_int)
+  print(Namespace.namespaced_const_int)
+  print(not_really_constant)
+  print(constexpr_int)
+  print(static_constexpr_int)
+
+  // TODO: Non-top-level constexpr variables currently are not imported at all (would be imported as static members)
+  //print(OtherNamespace.namespaced_constexpr_int)
+  //print(OtherNamespace.namespaced_static_constexpr_int)
+  //print(MyClass.class_static_constexpr_int)
+
+  print(MyClass().class_const_int)
+  print(MyClass.class_static_const_int)
+}
+
+// Only imported as external declarations:
+// CHECK: sil_global public_external [let] @not_really_constant : $Int32
+
+// CHECK:      sil shared [transparent] @$sSo9const_ints5Int32Vvg : $@convention(thin) () -> Int32 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int32, 42
+// CHECK-NEXT:   %1 = struct $Int32 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo9NamespaceO20namespaced_const_ints5Int32VvgZ : $@convention(method) (@thin Namespace.Type) -> Int32 {
+// CHECK-NEXT: // %0 "self"
+// CHECK-NEXT: bb0(%0 : $@thin Namespace.Type):
+// CHECK-NEXT:   debug_value %0, let, name "self", argno 1
+// CHECK-NEXT:   %2 = integer_literal $Builtin.Int32, 42
+// CHECK-NEXT:   %3 = struct $Int32 (%2)
+// CHECK-NEXT:   return %3
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo13constexpr_ints5Int32Vvg : $@convention(thin) () -> Int32 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int32, 42
+// CHECK-NEXT:   %1 = struct $Int32 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo20static_constexpr_ints5Int32Vvg : $@convention(thin) () -> Int32 {
+// CHECK-NEXT: bb0:
+// CHECK-NEXT:   %0 = integer_literal $Builtin.Int32, 42
+// CHECK-NEXT:   %1 = struct $Int32 (%0)
+// CHECK-NEXT:   return %1
+// CHECK-NEXT: }
+
+// CHECK:      sil shared [transparent] @$sSo7MyClassV22class_static_const_ints5Int32VvgZ : $@convention(method) (@thin MyClass.Type) -> Int32 {
+// CHECK-NEXT: // %0 "self"
+// CHECK-NEXT: bb0(%0 : $@thin MyClass.Type):
+// CHECK-NEXT:   debug_value %0, let, name "self", argno 1
+// CHECK-NEXT:   %2 = integer_literal $Builtin.Int32, 42
+// CHECK-NEXT:   %3 = struct $Int32 (%2)
+// CHECK-NEXT:   return %3
+// CHECK-NEXT: }
diff --git a/test/ClangImporter/const_values_fail.swift b/test/ClangImporter/const_values_fail.swift
new file mode 100644
index 0000000000000..999330b75365f
--- /dev/null
+++ b/test/ClangImporter/const_values_fail.swift
@@ -0,0 +1,19 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) %t/src/main.swift \
+// RUN:   -import-bridging-header %t/src/test.h \
+// RUN:   -module-name main -I %t -emit-sil -serialize-diagnostics -serialize-diagnostics-path %t/test.diag
+
+// RUN: c-index-test -read-diagnostics %t/test.diag 2>&1 | %FileCheck --check-prefix CHECK-DIAG %t/src/test.h
+
+//--- test.h
+static char other = 42;
+static const char static_const_char_that_is_not_const = 1 + other;
+// CHECK-DIAG: [[@LINE-1]]:{{.*}}: error: initializer element is not a compile-time constant
+// CHECK-DIAG: error: failed to import bridging header
+
+//--- main.swift
+func foo() {
+  print(static_const_char_that_is_not_const)
+}
diff --git a/test/ClangImporter/const_values_objc.swift b/test/ClangImporter/const_values_objc.swift
new file mode 100644
index 0000000000000..7a10407102113
--- /dev/null
+++ b/test/ClangImporter/const_values_objc.swift
@@ -0,0 +1,69 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t/modules) -Xcc -DCGFLOAT_IN_COREFOUNDATION -DCGFLOAT_IN_COREFOUNDATION -emit-module -o %t/modules/CoreFoundation.swiftmodule %clang-importer-sdk-path/swift-modules/CoreFoundation.swift
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t/modules) -Xcc -DCGFLOAT_IN_COREFOUNDATION -DCGFLOAT_IN_COREFOUNDATION -emit-module -o %t/modules/CoreGraphics.swiftmodule %clang-importer-sdk-path/swift-modules/CoreGraphics.swift
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t/modules) -Xcc -DCGFLOAT_IN_COREFOUNDATION -DCGFLOAT_IN_COREFOUNDATION -emit-module -o %t/modules/Foundation.swiftmodule %clang-importer-sdk-path/swift-modules/Foundation.swift
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk -I %t/modules) %t/src/main.swift \
+// RUN:   -import-bridging-header %t/src/test.h \
+// RUN:   -module-name main -I %t -emit-sil | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+//--- test.h
+#include <objc/objc.h>
+
+@import CoreFoundation;
+@import CoreGraphics;
+@import Foundation;
+
+@interface MyClass : NSObject
+@end
+
+__attribute__((swift_name("MyClass.value")))
+static const int MyClassValue = -1;
+
+static const CGFloat myFloatConstValue = 42.0;
+
+typedef CGFloat MyFloatType __attribute__((swift_wrapper(struct)));
+static const MyFloatType MyFloatTypeValue1 = 10;
+static const MyFloatType MyFloatTypeValue2 = 20;
+static const MyFloatType MyFloatTypeValue3 = 30;
+
+static const BOOL MyBoolConstantValue1 = YES;
+static const BOOL MyBoolConstantValue2 = NO;
+
+//--- main.swift
+func foo() {
+  print(MyClass.value)
+  print(myFloatConstValue)
+  print(MyFloatType.value1)
+  print(MyFloatType.value2)
+  print(MyFloatType.value3)
+  print(MyBoolConstantValue1)
+  print(MyBoolConstantValue2)
+}
+
+// CHECK:      // static MyClass.value.getter
+// CHECK-NEXT: // Isolation: nonisolated
+// CHECK-NEXT: sil shared [transparent] @$sSo7MyClassC5values5Int32VvgZ : $@convention(method) (@thick MyClass.Type) -> Int32 {
+// CHECK-NEXT: // %0 "self"
+// CHECK-NEXT: bb0(%0 : $@thick MyClass.Type):
+// CHECK-NEXT:   debug_value %0, let, name "self", argno 1
+// CHECK-NEXT:   %2 = integer_literal $Builtin.Int32, -1
+// CHECK-NEXT:   %3 = struct $Int32 (%2)
+// CHECK-NEXT:   return %3
+// CHECK-NEXT: }
+
+// CGFloats are not imported:
+
+// CHECK-NOT: // myFloatConstValue.getter
+// CHECK-NOT: // static MyFloatType.value1.getter
+// CHECK-NOT: // static MyFloatType.value2.getter
+// CHECK-NOT: // static MyFloatType.value3.getter
+
+// ObjCBools are not imported:
+
+// CHECK-NOT: // MyBoolConstantValue1.getter
+// CHECK-NOT: // MyBoolConstantValue2.getter
diff --git a/test/ClangImporter/ctypes_parse.swift b/test/ClangImporter/ctypes_parse.swift
index f14f4ec025882..12a56d3a31676 100644
--- a/test/ClangImporter/ctypes_parse.swift
+++ b/test/ClangImporter/ctypes_parse.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift %clang-importer-sdk -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated %clang-importer-sdk -verify-ignore-unknown
 
 import ctypes
 
@@ -214,6 +214,7 @@ func testFunctionPointers() {
 
   useFunctionPointer2(anotherFP)
   sizedFP = fp // expected-error {{cannot assign value of type 'fptr?' (aka 'Optional<@convention(c) (Int32) -> Int32>') to type '(@convention(c) (CInt, CInt, UnsafeMutableRawPointer?) -> Void)?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('fptr' (aka '@convention(c) (Int32) -> Int32') and '@convention(c) (CInt, CInt, UnsafeMutableRawPointer?) -> Void'}}
 }
 
 func testStructDefaultInit() {
diff --git a/test/ClangImporter/ctypes_parse_msvc.swift b/test/ClangImporter/ctypes_parse_msvc.swift
index 8a121f23feaf7..307a521bc659a 100644
--- a/test/ClangImporter/ctypes_parse_msvc.swift
+++ b/test/ClangImporter/ctypes_parse_msvc.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -Xcc -fms-extensions -import-objc-header %S/Inputs/ctypes_msvc.h -typecheck -verify %s
+// RUN: %target-swift-frontend -Xcc -fms-extensions -import-objc-header %S/Inputs/ctypes_msvc.h -typecheck -verify -verify-ignore-unrelated %s
 
 _ = T().uc
 _ = T(S(uc: 0))
diff --git a/test/ClangImporter/ctypes_parse_objc.swift b/test/ClangImporter/ctypes_parse_objc.swift
index 23208a2c43d11..7cb2d6677d4cb 100644
--- a/test/ClangImporter/ctypes_parse_objc.swift
+++ b/test/ClangImporter/ctypes_parse_objc.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift %clang-importer-sdk -enable-objc-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated %clang-importer-sdk -enable-objc-interop
 
 import ctypes
 import CoreGraphics
diff --git a/test/ClangImporter/ctypes_valist_wasm.swift b/test/ClangImporter/ctypes_valist_wasm.swift
new file mode 100644
index 0000000000000..5ec2856f85337
--- /dev/null
+++ b/test/ClangImporter/ctypes_valist_wasm.swift
@@ -0,0 +1,18 @@
+// RUN: %swift-frontend -target wasm32-unknown-wasip1 -parse-stdlib -module-name Swift -I %S/Inputs/custom-modules -typecheck %s
+
+// REQUIRES: CODEGENERATOR=WebAssembly
+
+import CVarArgs
+
+/// ===== Minimal stdlib definitions =====
+typealias Void = ()
+struct CVaListPointer {}
+// Optional definition is required for isOptional check in ClangImporter
+enum Optional<T> {}
+/// ======================================
+
+func testVaList() {
+  let _: (CVaListPointer) -> Void = CVarArgs.takeVaList
+  let _: (CVaListPointer) -> Void = CVarArgs.takeVaList2
+  let _: (CVaListPointer) -> Void = CVarArgs.takeVaList3
+}
diff --git a/test/ClangImporter/cxx_interop_ir.swift b/test/ClangImporter/cxx_interop_ir.swift
index f3f71b3222212..078c59b586595 100644
--- a/test/ClangImporter/cxx_interop_ir.swift
+++ b/test/ClangImporter/cxx_interop_ir.swift
@@ -1,9 +1,5 @@
 // RUN: %target-swiftxx-frontend -module-name cxx_ir -I %S/Inputs/custom-modules -emit-ir -o - -primary-file %s -Xcc -fignore-exceptions | %FileCheck %s
 
-// https://github.com/apple/swift/issues/55575
-// We can't yet call member functions correctly on Windows.
-// XFAIL: OS=windows-msvc
-
 import CXXInterop
 
 // CHECK-LABEL: define hidden swiftcc void @"$s6cxx_ir13indirectUsageyyF"()
@@ -42,8 +38,8 @@ func basicMethods(a: UnsafeMutablePointer<Methods>) -> Int32 {
 }
 
 // CHECK-LABEL: define hidden swiftcc i32 @"$s6cxx_ir17basicMethodsConst1as5Int32VSpySo0D0VG_tF"(ptr %0)
-// CHECK: [[THIS_PTR1:%.*]] = alloca %TSo7MethodsV, align {{4|8}}
-// CHECK: [[RESULT:%.*]] = call {{(signext )?}}i32 @{{_ZNK7Methods17SimpleConstMethodEi|"\?SimpleConstMethod@Methods@@QEBAHH@Z"}}(ptr [[THIS_PTR1]], i32 {{%?[0-9]+}})
+// CHECK: [[THIS_PTR1:%.*]] = alloca ptr, align {{4|8}}
+// CHECK: [[RESULT:%.*]] = call {{(signext )?}}i32 @{{_ZNK7Methods17SimpleConstMethodEi|"\?SimpleConstMethod@Methods@@QEBAHH@Z"}}(ptr %0, i32 {{%?[0-9]+}})
 // CHECK: ret i32 [[RESULT]]
 func basicMethodsConst(a: UnsafeMutablePointer<Methods>) -> Int32 {
   return a.pointee.SimpleConstMethod(3)
diff --git a/test/ClangImporter/duplicate_mainactor.swift b/test/ClangImporter/duplicate_mainactor.swift
index 9ae0e6cb68388..e891dcae6b0d3 100644
--- a/test/ClangImporter/duplicate_mainactor.swift
+++ b/test/ClangImporter/duplicate_mainactor.swift
@@ -5,6 +5,6 @@
 // REQUIRES: concurrency
 // REQUIRES: objc_interop
 
-// CHECK: DoubleMainActor.h:{{[0-9]+}}:{{[0-9]+}}: warning: this attribute for global actor '@MainActor' is invalid; the declaration already has attribute for global actor '@UIActor'
+// CHECK: DoubleMainActor.h:{{[0-9]+}}:{{[0-9]+}}: warning: this attribute for global actor '@MainActor' is invalid; the declaration already has attribute for global actor '@UIActor' [#ClangDeclarationImport]
 
-protocol P : DoubleMainActor {}
\ No newline at end of file
+protocol P : DoubleMainActor {}
diff --git a/test/ClangImporter/enum-error.swift b/test/ClangImporter/enum-error.swift
index c283741bd88d7..6c219b442f26b 100644
--- a/test/ClangImporter/enum-error.swift
+++ b/test/ClangImporter/enum-error.swift
@@ -118,7 +118,7 @@ func testError() {
 
 #if ERRORS
 class ObjCTest {
-  @objc func foo() -> TestError {} // expected-error {{method cannot be marked @objc because its result type cannot be represented in Objective-C}} expected-note {{Swift structs cannot be represented in Objective-C}}
+  @objc func foo() -> TestError {} // expected-error {{method cannot be marked '@objc' because its result type cannot be represented in Objective-C}} expected-note {{Swift structs cannot be represented in Objective-C}}
   @objc func bar() -> TestError.Code {} // okay
 }
 #endif
diff --git a/test/ClangImporter/enum-objc.swift b/test/ClangImporter/enum-objc.swift
index 83e7692226502..b9c2b211cb38d 100644
--- a/test/ClangImporter/enum-objc.swift
+++ b/test/ClangImporter/enum-objc.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-sil %s -enable-objc-interop -import-objc-header %S/Inputs/enum-objc.h -verify -enable-nonfrozen-enum-exhaustivity-diagnostics
+// RUN: %target-swift-frontend -emit-sil %s -enable-objc-interop -import-objc-header %S/Inputs/enum-objc.h -verify -verify-ignore-unrelated -enable-nonfrozen-enum-exhaustivity-diagnostics
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/enum-with-target.swift b/test/ClangImporter/enum-with-target.swift
index 78f8f15cb8727..07779a4e46282 100644
--- a/test/ClangImporter/enum-with-target.swift
+++ b/test/ClangImporter/enum-with-target.swift
@@ -1,5 +1,5 @@
-// RUN: %swift %clang-importer-sdk -target %target-cpu-apple-macosx51 -typecheck %s -verify
-// RUN: %swift %clang-importer-sdk -target %target-cpu-apple-macosx52 -typecheck %s -verify
+// RUN: %swift %clang-importer-sdk -target %target-cpu-apple-macosx51 -typecheck %s -verify -verify-ignore-unrelated
+// RUN: %swift %clang-importer-sdk -target %target-cpu-apple-macosx52 -typecheck %s -verify -verify-ignore-unrelated
 
 // REQUIRES: OS=macosx
 import Foundation
diff --git a/test/ClangImporter/enum.swift b/test/ClangImporter/enum.swift
index 3a9d2077d5392..37db41bb0d2bd 100644
--- a/test/ClangImporter/enum.swift
+++ b/test/ClangImporter/enum.swift
@@ -1,7 +1,7 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %s -verify
-// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %s 2>&1 | %FileCheck %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %s -verify -verify-ignore-unrelated -compiler-assertions
+// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %s -compiler-assertions 2>&1 | %FileCheck %s
 // -- Check that we can successfully round-trip.
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -D IRGEN -emit-ir -primary-file %s | %FileCheck -check-prefix=CHECK-IR %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -D IRGEN -emit-ir -primary-file %s -compiler-assertions | %FileCheck -check-prefix=CHECK-IR %s
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/foreign_errors.swift b/test/ClangImporter/foreign_errors.swift
index 0588f59eb681a..4374291274bc6 100644
--- a/test/ClangImporter/foreign_errors.swift
+++ b/test/ClangImporter/foreign_errors.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-silgen -parse-as-library -verify %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-silgen -parse-as-library -verify -verify-ignore-unrelated %s
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -O -parse-as-library -DEMIT_SIL %s
 
 // REQUIRES: objc_interop
diff --git a/test/ClangImporter/generic_compatibility_alias.swift b/test/ClangImporter/generic_compatibility_alias.swift
index b9a7f94c3afcb..f7f922dc3f177 100644
--- a/test/ClangImporter/generic_compatibility_alias.swift
+++ b/test/ClangImporter/generic_compatibility_alias.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %build-clang-importer-objc-overlays
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -module-name generic_compat_alias -I %S/Inputs/custom-modules -typecheck -verify %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -module-name generic_compat_alias -I %S/Inputs/custom-modules -typecheck -verify -verify-ignore-unrelated %s
 
 // REQUIRES: objc_interop
 // REQUIRES: OS=macosx
diff --git a/test/ClangImporter/import-as-member.swift b/test/ClangImporter/import-as-member.swift
index f617cb43ba0f0..3d3de93a17355 100644
--- a/test/ClangImporter/import-as-member.swift
+++ b/test/ClangImporter/import-as-member.swift
@@ -4,7 +4,7 @@
 // RUN: %FileCheck %S/Inputs/custom-modules/ImportAsMember.h <%t.txt
 // RUN: %FileCheck %S/Inputs/custom-modules/ImportAsMember_Private.h <%t.txt
 
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -F %S/Inputs/frameworks -I %S/Inputs/custom-modules -module-cache-path %t.mcp %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -F %S/Inputs/frameworks -I %S/Inputs/custom-modules -module-cache-path %t.mcp %s -verify -verify-ignore-unrelated
 
 import ImportAsMember
 import ImportAsMember_Private
diff --git a/test/ClangImporter/invocation-mcpu.swift b/test/ClangImporter/invocation-mcpu.swift
index 33b099a94f8f6..9d258ccc4366f 100644
--- a/test/ClangImporter/invocation-mcpu.swift
+++ b/test/ClangImporter/invocation-mcpu.swift
@@ -1,7 +1,12 @@
+// RUN: %swift %s -typecheck -parse-stdlib -dump-clang-diagnostics -target arm64e-apple-macos11.0 2>&1 | %FileCheck -check-prefix=CHECK-APPLE-M1 %s
+// RUN: %swift %s -typecheck -parse-stdlib -dump-clang-diagnostics -target arm64-apple-ios13.0-simulator 2>&1 | %FileCheck -check-prefix=CHECK-APPLE-M1 %s
+// CHECK-APPLE-M1: '-target-cpu' 'apple-m1' '-target-feature'
+
 // RUN: %swift %s -typecheck -parse-stdlib -dump-clang-diagnostics -target arm64e-apple-ios13.0 2>&1 | %FileCheck -check-prefix=CHECK-APPLE-A12 %s
-// RUN: %swift %s -typecheck -parse-stdlib -dump-clang-diagnostics -target arm64e-apple-macos11.0 2>&1 | %FileCheck -check-prefix=CHECK-APPLE-A12 %s
-// RUN: %swift %s -typecheck -parse-stdlib -dump-clang-diagnostics -target arm64e-apple-ios13.0-simulator 2>&1 | %FileCheck -check-prefix=CHECK-APPLE-A12 %s
-// CHECK-APPLE-A12: '-mcpu=apple-a12'
+// CHECK-APPLE-A12: '-target-cpu' 'apple-a12' '-target-feature'
 
 // RUN: %swift %s -typecheck -parse-stdlib -dump-clang-diagnostics -target arm64-apple-ios13.0 2>&1 | %FileCheck -check-prefix=CHECK-APPLE-A7 %s
-// CHECK-APPLE-A7: '-mcpu=apple-a7'
+// CHECK-APPLE-A7: '-target-cpu' 'apple-a7' '-target-feature'
+
+// RUN: %swift %s -typecheck -parse-stdlib -dump-clang-diagnostics -target arm64-apple-ios13.0 -target-cpu apple-a16 2>&1 | %FileCheck -check-prefix=CHECK-APPLE-A16 %s
+// CHECK-APPLE-A16: '-target-cpu' 'apple-a16' '-target-feature'
diff --git a/test/ClangImporter/macros.swift b/test/ClangImporter/macros.swift
index 6a9f07be9f54c..602a8b5881e78 100644
--- a/test/ClangImporter/macros.swift
+++ b/test/ClangImporter/macros.swift
@@ -1,7 +1,5 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -verify %s
-
-// Most of these don't pass: rdar://110071334
-// %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-experimental-cxx-interop -enable-objc-interop -typecheck -verify %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -verify -verify-ignore-unrelated %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -cxx-interoperability-mode=default -enable-objc-interop -typecheck -verify -verify-ignore-unrelated %s
 
 @_exported import macros
 
diff --git a/test/ClangImporter/macros_redef.swift b/test/ClangImporter/macros_redef.swift
index 319b46046a342..b05d7aa8c8905 100644
--- a/test/ClangImporter/macros_redef.swift
+++ b/test/ClangImporter/macros_redef.swift
@@ -1,5 +1,5 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -enable-objc-interop -import-objc-header %S/Inputs/macros_redef.h -emit-silgen %s | %FileCheck -check-prefix=NEGATIVE %s
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -enable-objc-interop -import-objc-header %S/Inputs/macros_redef.h -DCONFLICT -typecheck -verify %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -enable-objc-interop -import-objc-header %S/Inputs/macros_redef.h -DCONFLICT -typecheck -verify -verify-ignore-unrelated %s
 
 // NEGATIVE-NOT: OLDTAG
 
diff --git a/test/ClangImporter/nested_protocol_name.swift b/test/ClangImporter/nested_protocol_name.swift
index 5b4f4d137d537..0e4c907155a52 100644
--- a/test/ClangImporter/nested_protocol_name.swift
+++ b/test/ClangImporter/nested_protocol_name.swift
@@ -1,6 +1,6 @@
 // REQUIRES: objc_interop
 
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -import-objc-header %S/Inputs/nested_protocol_name.h -typecheck -verify %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -import-objc-header %S/Inputs/nested_protocol_name.h -typecheck -verify -verify-ignore-unrelated %s
 
 // RUN: echo '#include "nested_protocol_name.h"' > %t.m
 // RUN: %target-swift-ide-test -source-filename %s -print-header -header-to-print %S/Inputs/nested_protocol_name.h -import-objc-header %S/Inputs/nested_protocol_name.h --cc-args %target-cc-options -fsyntax-only %t.m -I %S/Inputs > %t.txt
diff --git a/test/ClangImporter/nullability.swift b/test/ClangImporter/nullability.swift
index 9a7ab8ab4b6b4..9a55ce1b19ee2 100644
--- a/test/ClangImporter/nullability.swift
+++ b/test/ClangImporter/nullability.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -I %S/Inputs/custom-modules %s -import-underlying-module -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -I %S/Inputs/custom-modules %s -import-underlying-module -verify -verify-ignore-unrelated
 
 import CoreCooling
 
diff --git a/test/ClangImporter/objc-cross-module-override.swift b/test/ClangImporter/objc-cross-module-override.swift
index 4a8b4133e0fb7..a686e3924d33e 100644
--- a/test/ClangImporter/objc-cross-module-override.swift
+++ b/test/ClangImporter/objc-cross-module-override.swift
@@ -11,7 +11,7 @@
 import ImageInitializers
 
 final class MyImage : Image {
-  // CHECK: non-@objc initializer 'init(imageLiteralResourceName:)' is declared in extension of 'Image' and cannot be overridden
+  // CHECK: non-'@objc' initializer 'init(imageLiteralResourceName:)' is declared in extension of 'Image' and cannot be overridden
   // Make sure we aren't emitting a fixit into the extant module...
   // CHECK-NOT: add '@objc' to make this declaration overridable
   // CHECK: ImageInitializers.Image.init:{{.*}}: note: overridden declaration is here
diff --git a/test/ClangImporter/objc_async.swift b/test/ClangImporter/objc_async.swift
index cc6e5fa35f405..e46f66431d3f4 100644
--- a/test/ClangImporter/objc_async.swift
+++ b/test/ClangImporter/objc_async.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules %s -verify -verify-additional-file %swift_src_root/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h -strict-concurrency=targeted -parse-as-library -enable-experimental-feature SendableCompletionHandlers
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules %s -verify -verify-ignore-unrelated -verify-additional-file %swift_src_root/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h -strict-concurrency=targeted -parse-as-library -enable-experimental-feature SendableCompletionHandlers
 
 // REQUIRES: objc_interop
 // REQUIRES: concurrency
@@ -137,22 +137,22 @@ func testSendableAttrs(
 
   doSomethingConcurrently {
     print(sendableClass)               // no-error
-    print(nonSendableClass)            // expected-warning{{capture of 'nonSendableClass' with non-sendable type 'NonSendableClass' in a '@Sendable' closure}}
+    print(nonSendableClass)            // expected-warning{{capture of 'nonSendableClass' with non-Sendable type 'NonSendableClass' in a '@Sendable' closure}}
 
     print(sendableEnum)                // no-error
-    print(nonSendableEnum)             // expected-warning{{capture of 'nonSendableEnum' with non-sendable type 'NonSendableEnum' in a '@Sendable' closure}}
+    print(nonSendableEnum)             // expected-warning{{capture of 'nonSendableEnum' with non-Sendable type 'NonSendableEnum' in a '@Sendable' closure}}
 
     print(sendableOptions)             // no-error
-    print(nonSendableOptions)          // expected-warning{{capture of 'nonSendableOptions' with non-sendable type 'NonSendableOptions' in a '@Sendable' closure}}
+    print(nonSendableOptions)          // expected-warning{{capture of 'nonSendableOptions' with non-Sendable type 'NonSendableOptions' in a '@Sendable' closure}}
 
     print(sendableError)               // no-error
     print(nonSendableError)            // no-error--we don't respect `@_nonSendable` on `ns_error_domain` types because all errors are Sendable
 
     print(sendableStringEnum)          // no-error
-    print(nonSendableStringEnum)       // expected-warning{{capture of 'nonSendableStringEnum' with non-sendable type 'NonSendableStringEnum' in a '@Sendable' closure}}
+    print(nonSendableStringEnum)       // expected-warning{{capture of 'nonSendableStringEnum' with non-Sendable type 'NonSendableStringEnum' in a '@Sendable' closure}}
 
     print(sendableStringStruct)        // no-error
-    print(nonSendableStringStruct)     // expected-warning{{capture of 'nonSendableStringStruct' with non-sendable type 'NonSendableStringStruct' in a '@Sendable' closure}}
+    print(nonSendableStringStruct)     // expected-warning{{capture of 'nonSendableStringStruct' with non-Sendable type 'NonSendableStringStruct' in a '@Sendable' closure}}
   }
 }
 
@@ -392,7 +392,7 @@ extension SomeWrapper: Sendable where T: Sendable {}
   func makeCall(slowServer: SlowServer) {
     slowServer.doSomethingSlow("churn butter") { (_ : Int) in
       let _ = self.isolatedThing
-      // expected-warning@-1 {{main actor-isolated property 'isolatedThing' can not be referenced from a Sendable closure; this is an error in the Swift 6 language mode}}
+      // expected-warning@-1 {{main actor-isolated property 'isolatedThing' can not be referenced from a Sendable closure}}
     }
   }
 }
@@ -404,3 +404,9 @@ extension CoffeeDelegate  {
         return await self.icedMochaServiceGenerateMocha!(NSObject())
     }
 }
+
+@MainActor
+func testGetSendableClasses() async {
+  let x = ImportObjCAsyncGetter()
+  _ = await x.sendableClasses
+}
diff --git a/test/ClangImporter/objc_async_conformance.swift b/test/ClangImporter/objc_async_conformance.swift
index a23b9897387d4..45ab6b898a001 100644
--- a/test/ClangImporter/objc_async_conformance.swift
+++ b/test/ClangImporter/objc_async_conformance.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules -disable-availability-checking  %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules -disable-availability-checking  %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 // REQUIRES: concurrency
diff --git a/test/ClangImporter/objc_async_macos.swift b/test/ClangImporter/objc_async_macos.swift
index 804e71a64b14c..3bb3e2b7e14bd 100644
--- a/test/ClangImporter/objc_async_macos.swift
+++ b/test/ClangImporter/objc_async_macos.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules  %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules  %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 // REQUIRES: concurrency
diff --git a/test/ClangImporter/objc_bridging_generics.swift b/test/ClangImporter/objc_bridging_generics.swift
index 65db7c46798f7..65d1bb5440703 100644
--- a/test/ClangImporter/objc_bridging_generics.swift
+++ b/test/ClangImporter/objc_bridging_generics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -verify -swift-version 4 -I %S/Inputs/custom-modules %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -verify -verify-ignore-unrelated -swift-version 4 -I %S/Inputs/custom-modules %s
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/objc_class_subscript.swift b/test/ClangImporter/objc_class_subscript.swift
index 37f770e367a07..4d59605b3db61 100644
--- a/test/ClangImporter/objc_class_subscript.swift
+++ b/test/ClangImporter/objc_class_subscript.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %build-clang-importer-objc-overlays
 
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -typecheck -I %S/Inputs/custom-modules %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -typecheck -I %S/Inputs/custom-modules %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/objc_diags.swift b/test/ClangImporter/objc_diags.swift
index 539e8af48547e..cc85b0e9e5bb8 100644
--- a/test/ClangImporter/objc_diags.swift
+++ b/test/ClangImporter/objc_diags.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck %s -verify -verify-ignore-unrelated
 
 import ObjectiveC
 
diff --git a/test/ClangImporter/objc_direct.swift b/test/ClangImporter/objc_direct.swift
index cfcd04ef31715..fa3b11972be3f 100644
--- a/test/ClangImporter/objc_direct.swift
+++ b/test/ClangImporter/objc_direct.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend-verify -typecheck %s -enable-objc-interop -import-objc-header %S/../Inputs/objc_direct.h
+// RUN: %target-swift-frontend-verify -verify-ignore-unrelated -typecheck %s -enable-objc-interop -import-objc-header %S/../Inputs/objc_direct.h
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/objc_factory_method.swift b/test/ClangImporter/objc_factory_method.swift
index aaf29c54cce13..d3590a5bfa584 100644
--- a/test/ClangImporter/objc_factory_method.swift
+++ b/test/ClangImporter/objc_factory_method.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %build-clang-importer-objc-overlays
 
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -target %target-cpu-apple-macosx51 -typecheck %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -target %target-cpu-apple-macosx51 -typecheck %s -verify -verify-ignore-unrelated
 
 // REQUIRES: OS=macosx
 // REQUIRES: objc_interop
@@ -28,7 +28,7 @@ func testInstanceTypeFactoryMethodInherited() {
 }
 
 func testFactoryWithLaterIntroducedInit() {
-    // expected-note @-1 4{{add @available attribute to enclosing global function}}
+    // expected-note @-1 4{{add '@available' attribute to enclosing global function}}
   // Prefer importing more available factory initializer over less
   // less available convenience initializer
   _ = NSHavingConvenienceFactoryAndLaterConvenienceInit(flim:5)
diff --git a/test/ClangImporter/objc_generics_conformance.swift b/test/ClangImporter/objc_generics_conformance.swift
index 86084bb36ee49..6cb621a23b48a 100644
--- a/test/ClangImporter/objc_generics_conformance.swift
+++ b/test/ClangImporter/objc_generics_conformance.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -verify -swift-version 4 -I %S/Inputs/custom-modules %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -verify -verify-ignore-unrelated -swift-version 4 -I %S/Inputs/custom-modules %s
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/objc_implicit_with.swift b/test/ClangImporter/objc_implicit_with.swift
index ec5702c83bd4f..2024cfa0541b6 100644
--- a/test/ClangImporter/objc_implicit_with.swift
+++ b/test/ClangImporter/objc_implicit_with.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/objc_init.swift b/test/ClangImporter/objc_init.swift
index c795ff4bb2341..adde85e45311c 100644
--- a/test/ClangImporter/objc_init.swift
+++ b/test/ClangImporter/objc_init.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -I %S/Inputs/custom-modules %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -I %S/Inputs/custom-modules %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/objc_init_redundant.swift b/test/ClangImporter/objc_init_redundant.swift
index eb49c23e5c30d..dfa7fa7cee5ee 100644
--- a/test/ClangImporter/objc_init_redundant.swift
+++ b/test/ClangImporter/objc_init_redundant.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk -I %S/Inputs/custom-modules -F %S/Inputs/frameworks) -import-underlying-module -import-objc-header %S/Inputs/objc_init_redundant_bridging.h -emit-sil %s -verify -swift-version 5 -enable-library-evolution
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk -I %S/Inputs/custom-modules -F %S/Inputs/frameworks) -import-underlying-module -import-objc-header %S/Inputs/objc_init_redundant_bridging.h -emit-sil %s -verify -verify-ignore-unrelated -swift-version 5 -enable-library-evolution
 // RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk -I %S/Inputs/custom-modules -F %S/Inputs/frameworks) -import-underlying-module -import-objc-header %S/Inputs/objc_init_redundant_bridging.h -emit-sil %s -swift-version 5 -enable-library-evolution > %t.log 2>&1
 // RUN: %FileCheck %s < %t.log
 
diff --git a/test/ClangImporter/objc_isolation_complete.swift b/test/ClangImporter/objc_isolation_complete.swift
index 24a9b0f98f10d..1788f93e92e30 100644
--- a/test/ClangImporter/objc_isolation_complete.swift
+++ b/test/ClangImporter/objc_isolation_complete.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules %s -verify -strict-concurrency=complete -parse-as-library
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules %s -verify -verify-ignore-unrelated -strict-concurrency=complete -parse-as-library
 
 // REQUIRES: objc_interop
 // REQUIRES: concurrency
diff --git a/test/ClangImporter/objc_missing_designated_init.swift b/test/ClangImporter/objc_missing_designated_init.swift
index 1cd5ff1f338de..546fdf7df954a 100644
--- a/test/ClangImporter/objc_missing_designated_init.swift
+++ b/test/ClangImporter/objc_missing_designated_init.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -I %S/Inputs/custom-modules %s -swift-version 4 -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -I %S/Inputs/custom-modules %s -swift-version 4 -verify -verify-ignore-unrelated
 
 import UnimportableMembers
 import UnimportableMembersUser
diff --git a/test/ClangImporter/objc_nsmanagedobject.swift b/test/ClangImporter/objc_nsmanagedobject.swift
index 0d760cc5dc14e..eece181b242dc 100644
--- a/test/ClangImporter/objc_nsmanagedobject.swift
+++ b/test/ClangImporter/objc_nsmanagedobject.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -typecheck -parse-as-library -verify %s %S/Inputs/objc_nsmanaged_other.swift
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -typecheck -parse-as-library -verify -primary-file %s %S/Inputs/objc_nsmanaged_other.swift
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -typecheck -parse-as-library -verify -verify-ignore-unrelated %s %S/Inputs/objc_nsmanaged_other.swift
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -typecheck -parse-as-library -verify -verify-ignore-unrelated -primary-file %s %S/Inputs/objc_nsmanaged_other.swift
 
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -emit-silgen -parse-as-library -o /dev/null -DNO_ERROR %s %S/Inputs/objc_nsmanaged_other.swift
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/custom-modules -emit-silgen -parse-as-library -o /dev/null -DNO_ERROR -primary-file %s %S/Inputs/objc_nsmanaged_other.swift
diff --git a/test/ClangImporter/objc_override.swift b/test/ClangImporter/objc_override.swift
index ad2fb3ece0ab3..aaf81ea6ac552 100644
--- a/test/ClangImporter/objc_override.swift
+++ b/test/ClangImporter/objc_override.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -I %S/Inputs/custom-modules %s -verify -verify-ignore-unknown
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -I %S/Inputs/custom-modules %s -verify -verify-ignore-unrelated -verify-ignore-unknown
 
 // REQUIRES: objc_interop
 
@@ -83,9 +83,23 @@ class SomeCellSub5 : SomeCell {
   func otherIsEnabled() { } // should not conflict
 }
 
+class SomeCellSub6 : SomeCell {
+  @available(*, unavailable)
+  @objc override init(string: String) {
+    super.init(string: string)
+  }
+}
+
+class SomeCellSub7 : SomeCell {
+  @available(swift, obsoleted: 4)
+  @objc override init(string: String) {
+    super.init(string: string)
+  }
+}
+
 class FailSub : FailBase {
-  override init(value: Int) { try! super.init(value: value) } // expected-error {{overriding a throwing @objc initializer with a non-throwing initializer is not supported}}
-  override class func processValue() {} // expected-error {{overriding a throwing @objc method with a non-throwing method is not supported}}
+  override init(value: Int) { try! super.init(value: value) } // expected-error {{overriding a throwing '@objc' initializer with a non-throwing initializer is not supported}}
+  override class func processValue() {} // expected-error {{overriding a throwing '@objc' method with a non-throwing method is not supported}}
 }
 
 class CallbackSubA : CallbackBase {
diff --git a/test/ClangImporter/objc_parse.swift b/test/ClangImporter/objc_parse.swift
index d3cfcb160904d..d7562e5615121 100644
--- a/test/ClangImporter/objc_parse.swift
+++ b/test/ClangImporter/objc_parse.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -I %S/Inputs/custom-modules %s -verify -disable-experimental-clang-importer-diagnostics
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -I %S/Inputs/custom-modules %s -verify -verify-ignore-unrelated -disable-experimental-clang-importer-diagnostics
 
 // REQUIRES: objc_interop
 
@@ -648,24 +648,24 @@ class NewtypeUser {
   @objc func stringNewtype(a: SNTErrorDomain) {} // expected-error {{'SNTErrorDomain' has been renamed to 'ErrorDomain'}}{{31-45=ErrorDomain}}
   @objc func stringNewtypeOptional(a: SNTErrorDomain?) {} // expected-error {{'SNTErrorDomain' has been renamed to 'ErrorDomain'}}{{39-53=ErrorDomain}}
   @objc func intNewtype(a: MyInt) {}
-  @objc func intNewtypeOptional(a: MyInt?) {} // expected-error {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
-  @objc func intNewtypeArray(a: [MyInt]) {} // expected-error {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  @objc func intNewtypeOptional(a: MyInt?) {} // expected-error {{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
+  @objc func intNewtypeArray(a: [MyInt]) {} // expected-error {{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-1 {{Swift structs cannot be represented in Objective-C}}
-  @objc func intNewtypeDictionary(a: [MyInt: NSObject]) {} // expected-error {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  @objc func intNewtypeDictionary(a: [MyInt: NSObject]) {} // expected-error {{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-1 {{Swift structs cannot be represented in Objective-C}}
   @objc func cfNewtype(a: CFNewType) {}
-  @objc func cfNewtypeArray(a: [CFNewType]) {} // expected-error {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  @objc func cfNewtypeArray(a: [CFNewType]) {} // expected-error {{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-1 {{Swift structs cannot be represented in Objective-C}}
 
   typealias MyTuple = (Int, AnyObject?)
   typealias MyNamedTuple = (a: Int, b: AnyObject?)
   
   @objc func blockWithTypealias(_ input: @escaping (MyTuple) -> MyInt) {}
-  // expected-error@-1{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // expected-error@-1{{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2{{function types cannot be represented in Objective-C}}
 
   @objc func blockWithTypealiasWithNames(_ input: (MyNamedTuple) -> MyInt) {}
-  // expected-error@-1{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // expected-error@-1{{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2{{function types cannot be represented in Objective-C}}
 }
 
diff --git a/test/ClangImporter/objc_parse_verifier.swift b/test/ClangImporter/objc_parse_verifier.swift
index 3ad28b6f677e8..92919c72962b9 100644
--- a/test/ClangImporter/objc_parse_verifier.swift
+++ b/test/ClangImporter/objc_parse_verifier.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -emit-sil -I %S/Inputs/custom-modules %s -verify > /dev/null
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -emit-sil -I %S/Inputs/custom-modules %s -verify -verify-ignore-unrelated > /dev/null
 
 // expected-no-diagnostics
 
diff --git a/test/ClangImporter/objc_protocol_renaming.swift b/test/ClangImporter/objc_protocol_renaming.swift
index a9f8f23c7394d..5ffd954e2d8fb 100644
--- a/test/ClangImporter/objc_protocol_renaming.swift
+++ b/test/ClangImporter/objc_protocol_renaming.swift
@@ -7,7 +7,7 @@
 
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %S/Inputs/custom-modules -I %t) -emit-module -o %t %S/Inputs/ImplementProtoRenaming.swift
 
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %S/Inputs/custom-modules -I %t) -typecheck %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %S/Inputs/custom-modules -I %t) -typecheck %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/objc_runtime_visible.swift b/test/ClangImporter/objc_runtime_visible.swift
index cd347c26bcc4d..24858f0a38d60 100644
--- a/test/ClangImporter/objc_runtime_visible.swift
+++ b/test/ClangImporter/objc_runtime_visible.swift
@@ -3,7 +3,7 @@
 import ObjCRuntimeVisible
 
 extension A {
-  @objc func foo() { } // expected-error{{instance method cannot be marked @objc because class 'A' is only visible via the Objective-C runtime}}
+  @objc func foo() { } // expected-error{{instance method cannot be marked '@objc' because class 'A' is only visible via the Objective-C runtime}}
   func bar() {} // okay, implicitly non-objc
 }
 
@@ -16,5 +16,5 @@ class B : A { } // expected-error{{cannot inherit from class 'A' because it is o
 protocol SwiftProto {}
 @objc protocol ObjCProto {}
 
-extension A: ObjCProto {} // expected-error {{class 'A' cannot conform to @objc protocol 'ObjCProto' because the class is only visible via the Objective-C runtime}}
+extension A: ObjCProto {} // expected-error {{class 'A' cannot conform to '@objc' protocol 'ObjCProto' because the class is only visible via the Objective-C runtime}}
 extension A: SwiftProto {} // okay
diff --git a/test/ClangImporter/objc_subscript.swift b/test/ClangImporter/objc_subscript.swift
index e7d73a9383d38..6ce37bdd1e680 100644
--- a/test/ClangImporter/objc_subscript.swift
+++ b/test/ClangImporter/objc_subscript.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %build-clang-importer-objc-overlays
 
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -emit-sil -I %S/Inputs/custom-modules %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -emit-sil -I %S/Inputs/custom-modules %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/overlay.swift b/test/ClangImporter/overlay.swift
index 6f949d87ae74a..26bc489f0e4bc 100644
--- a/test/ClangImporter/overlay.swift
+++ b/test/ClangImporter/overlay.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules %s
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -I %S/Inputs/custom-modules -DREVERSED %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -I %S/Inputs/custom-modules -DREVERSED %s
 
 // REQUIRES: objc_interop
 
@@ -19,3 +19,4 @@ Redeclaration.NSStringToNSString(AppKit.NSStringToNSString("abc")) // expected-w
 
 let viaStruct: Redeclaration.FooStruct1 = AppKit.FooStruct1()
 let forwardDecl: Redeclaration.Tribool = AppKit.Tribool() // expected-error {{no type named 'Tribool' in module 'Redeclaration'}}
+// expected-error@-1 {{missing argument for parameter #1 in call}}
diff --git a/test/ClangImporter/pcm-emit-direct-cc1-mode.swift b/test/ClangImporter/pcm-emit-direct-cc1-mode.swift
index f5048b9e3d5fd..6bc26ca317722 100644
--- a/test/ClangImporter/pcm-emit-direct-cc1-mode.swift
+++ b/test/ClangImporter/pcm-emit-direct-cc1-mode.swift
@@ -15,5 +15,7 @@
 // CHECK-CLANG-SAME: '-fmodules'
 // CHECK-CLANG-NOT: clang importer driver args
 
+// XFAIL: OS=linux-androideabi
+
 import script
 var _ : ScriptTy
diff --git a/test/ClangImporter/print-module-map-paths.swift b/test/ClangImporter/print-module-map-paths.swift
index 5e82294a7732d..d5fac537f2679 100644
--- a/test/ClangImporter/print-module-map-paths.swift
+++ b/test/ClangImporter/print-module-map-paths.swift
@@ -1,17 +1,27 @@
 // RUN: %empty-directory(%t)
 // RUN: mkdir -p %t/resources/linux/armv7 %t/sdk/usr/include %t/sdk/usr/lib/swift/linux/armv7
-// RUN: touch %t/sdk/usr/include/{inttypes,stdint,unistd}.h
-
-// RUN: touch %t/resources/linux/armv7/{SwiftGlibc.h,glibc.modulemap}
-// RUN: touch %t/sdk/usr/lib/swift/linux/armv7/{SwiftGlibc.h,glibc.modulemap}
+// RUN: touch %t/sdk/usr/include/inttypes.h
+// RUN: touch %t/sdk/usr/include/stdint.h
+// RUN: touch %t/sdk/usr/include/unistd.h
+
+// RUN: touch %t/resources/linux/armv7/SwiftGlibc.h
+// RUN: touch %t/resources/linux/armv7/glibc.modulemap
+// RUN: touch %t/sdk/usr/lib/swift/linux/armv7/SwiftGlibc.h
+// RUN: touch %t/sdk/usr/lib/swift/linux/armv7/glibc.modulemap
 // RUN: %swift %s -typecheck -parse-stdlib -dump-clang-diagnostics -target armv7-unknown-linux-gnueabihf -sdk %t/sdk -resource-dir %t/resources 2>&1 | %FileCheck -check-prefix=CHECK-LINUX %s
 
-// RUN: cp %S/../../stdlib/public/Cxx/{cxxshim/libcxxshim.modulemap,libstdcxx/libstdcxx.h,libstdcxx/libstdcxx.modulemap} %t/resources/linux
+// RUN: cp %S/../../stdlib/public/Cxx/cxxshim/libcxxshim.modulemap %t/resources/linux
+// RUN: cp %S/../../stdlib/public/Cxx/libstdcxx/libstdcxx.h %t/resources/linux
+// RUN: cp %S/../../stdlib/public/Cxx/libstdcxx/libstdcxx.modulemap %t/resources/linux
 // RUN: %target-swift-frontend %s -typecheck -parse-stdlib -dump-clang-diagnostics -resource-dir %t/resources -cxx-interoperability-mode=default 2>&1 | %FileCheck -check-prefix=CHECK-CXX -check-prefix=CHECK-%target-os-CXX %s
 
 // RUN: mkdir -p %t/resources/android/aarch64 %t/sdk/usr/lib/swift/android/aarch64
-// RUN: cp %S/../../stdlib/public/Platform/{SwiftAndroidNDK.h,SwiftBionic.h,android.modulemap} %t/resources/android/aarch64
-// RUN: cp %S/../../stdlib/public/Platform/{SwiftAndroidNDK.h,SwiftBionic.h,android.modulemap} %t/sdk/usr/lib/swift/android/aarch64
+// RUN: cp %S/../../stdlib/public/Platform/SwiftAndroidNDK.h %t/resources/android/aarch64
+// RUN: cp %S/../../stdlib/public/Platform/SwiftBionic.h %t/resources/android/aarch64
+// RUN: cp %S/../../stdlib/public/Platform/android.modulemap %t/resources/android/aarch64
+// RUN: cp %S/../../stdlib/public/Platform/SwiftAndroidNDK.h %t/sdk/usr/lib/swift/android/aarch64
+// RUN: cp %S/../../stdlib/public/Platform/SwiftBionic.h %t/sdk/usr/lib/swift/android/aarch64
+// RUN: cp %S/../../stdlib/public/Platform/android.modulemap %t/sdk/usr/lib/swift/android/aarch64
 // RUN: %swift %s -typecheck -parse-stdlib -dump-clang-diagnostics -target aarch64-unknown-linux-android -sdk %t/sdk -resource-dir %t/resources 2>&1 | %FileCheck -check-prefix=CHECK-ANDROID %s
 
 // RUN: cp %S/../../stdlib/public/Cxx/cxxshim/libcxxshim.modulemap %t/resources/android
diff --git a/test/ClangImporter/protocol-member-renaming.swift b/test/ClangImporter/protocol-member-renaming.swift
index 65c07c9b63b86..54169f58faed4 100644
--- a/test/ClangImporter/protocol-member-renaming.swift
+++ b/test/ClangImporter/protocol-member-renaming.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -import-objc-header %S/Inputs/protocol-member-renaming.h -verify %s
+// RUN: %target-swift-frontend -typecheck -import-objc-header %S/Inputs/protocol-member-renaming.h -verify -verify-ignore-unrelated %s
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/rdar123543707.swift b/test/ClangImporter/rdar123543707.swift
index e631a80256fe1..93daffa572359 100644
--- a/test/ClangImporter/rdar123543707.swift
+++ b/test/ClangImporter/rdar123543707.swift
@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-typecheck-verify-swift -F %S/Inputs/frameworks -module-cache-path %t/mcp1  -target %target-stable-abi-triple
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -F %S/Inputs/frameworks -module-cache-path %t/mcp1  -target %target-stable-abi-triple
 
 // REQUIRES: objc_interop
 
@@ -7,8 +7,10 @@ import Module
 import Module_Private.Sub4
 
 @_objcImplementation extension Module {
-  // expected-warning@-1 {{extension for main class interface should provide implementation for class method 'version()'}}
-  // expected-warning@-2 {{extension for main class interface should provide implementation for class method 'alloc()'}}
+  // expected-warning@-1 {{extension for main class interface does not provide all required implementations}}
+  // expected-note@-2 {{missing class method 'version()'}}
+  // expected-note@-3 {{missing class method 'alloc()'}}
+  // expected-note@-4 {{add stubs for missing '@implementation' requirements}} {{40-40=\n    @objc(version)\n    open class func version() -> UnsafePointer<CChar>! {\n        <#code#>\n    \}\n\n    @objc(alloc)\n    open class func alloc() -> Self! {\n        <#code#>\n    \}\n}}
 }
 
 extension Module: @retroactive ModuleProto {} // no-error
diff --git a/test/ClangImporter/regionbasedisolation.swift b/test/ClangImporter/regionbasedisolation.swift
new file mode 100644
index 0000000000000..d5f3f89cef0df
--- /dev/null
+++ b/test/ClangImporter/regionbasedisolation.swift
@@ -0,0 +1,164 @@
+// RUN: %target-swift-frontend %s -import-objc-header %S/Inputs/regionbasedisolation.h -verify -verify-additional-prefix ni- -c -swift-version 6
+// RUN: %target-swift-frontend %s -import-objc-header %S/Inputs/regionbasedisolation.h -verify -verify-additional-prefix ni-ns- -c -swift-version 6 -enable-upcoming-feature NonisolatedNonsendingByDefault
+// RUN: %target-swift-frontend %s -import-objc-header %S/Inputs/regionbasedisolation.h -emit-silgen -swift-version 6 | %FileCheck %s
+
+// REQUIRES: objc_interop
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+extension ObjCObject {
+  // CHECK-LABEL: sil hidden [ossa] @$sSo10ObjCObjectC20regionbasedisolationE11sendObjectsSaySo8NSObjectCGyYaKF : $@convention(method) @async (@guaranteed ObjCObject) -> (@sil_sending @owned Array<NSObject>, @error any Error) {
+  // CHECK: bb0([[SELF:%.*]] : @guaranteed $ObjCObject):
+
+  // Our result.
+  // CHECK: [[RESULT:%.*]] = alloc_stack $Array<NSObject>
+
+  // Our method.
+  // CHECK: [[METHOD:%.*]] = objc_method [[SELF]], #ObjCObject.loadObjects!foreign : (ObjCObject) -> () async throws -> [NSObject], $@convention(objc_method) (@convention(block) @Sendable (Optional<NSArray>, Optional<NSError>) -> (), ObjCObject) -> ()
+
+  // Begin setting up the unsafe continuation for our method. Importantly note
+  // that [[UNSAFE_CONT]] is Sendable, so we lose any connection from the
+  // continuation addr to any uses of the UnsafeContinuation.
+  //
+  // CHECK: [[CONT:%.*]] = get_async_continuation_addr [throws] Array<NSObject>, [[RESULT]]
+  // CHECK: [[UNSAFE_CONT:%.*]] = struct $UnsafeContinuation<Array<NSObject>, any Error> ([[CONT]])
+
+  // Then prepare the block storage.
+  // CHECK: [[BLOCK_STORAGE:%.*]] = alloc_stack $@block_storage Any
+  // CHECK: [[PROJECT_BLOCK_STORAGE:%.*]] = project_block_storage [[BLOCK_STORAGE]]
+  // CHECK: [[EXISTENTIAL_BLOCK_STORAGE:%.*]] = init_existential_addr [[PROJECT_BLOCK_STORAGE]]
+
+  // Then create a checked continuation from the unsafe continuation.
+  //
+  // CHECK: [[CREATE_CHECKED_CONT:%.*]] = function_ref @$ss34_createCheckedThrowingContinuationyScCyxs5Error_pGSccyxsAB_pGnlF : $@convention(thin) <τ_0_0> (UnsafeContinuation<τ_0_0, any Error>) -> @out CheckedContinuation<τ_0_0, any Error>
+  // CHECK: [[CHECKED_CONT:%.*]] = alloc_stack $CheckedContinuation<Array<NSObject>, any Error>
+  // CHECK: apply [[CREATE_CHECKED_CONT]]<Array<NSObject>>([[CHECKED_CONT]], [[UNSAFE_CONT]])
+
+  // Then place the checked continuation into the block storage and perform a
+  // merge_isolation_region in between the block storage and the result to
+  // propagate that the result and the block storage are apart of the same
+  // region despite the UnsafeContinuation blocking the relation in between
+  // them.
+  //
+  // CHECK: copy_addr [take] [[CHECKED_CONT]] to [init] [[EXISTENTIAL_BLOCK_STORAGE]]
+  // CHECK: merge_isolation_region [[BLOCK_STORAGE]], [[RESULT]]
+
+  // Then create the actual block. NOTE: Since the block is @Sendable, the block
+  // does not propagate regions.
+  //
+  // CHECK: [[COMPLETION_HANDLER_BLOCK:%.*]] = function_ref @$sSo7NSArrayCSgSo7NSErrorCSgIeyBhyy_SaySo8NSObjectCGTz_ : $@convention(c) @Sendable (@inout_aliasable @block_storage Any, Optional<NSArray>, Optional<NSError>) -> ()
+  // CHECK: [[COMPLETION_BLOCK:%.*]] = init_block_storage_header [[BLOCK_STORAGE]], invoke [[COMPLETION_HANDLER_BLOCK]]
+  //
+  // Since the block is @Sendable, it does not propagate the connection in
+  // between self and the block storage when we just call the method. Thus we
+  // need to perform a merge_isolation_region to communicate that the block
+  // storage and self are part of the same region.
+  //
+  // CHECK: merge_isolation_region [[SELF]], [[BLOCK_STORAGE]]
+  //
+  // Then call the method.
+  // CHECK: apply [[METHOD]]([[COMPLETION_BLOCK]], [[SELF]])
+  // CHECK: } // end sil function '$sSo10ObjCObjectC20regionbasedisolationE11sendObjectsSaySo8NSObjectCGyYaKF'
+
+  func sendObjects() async throws -> sending [NSObject] {
+    // We emit an error since loadObjects just returns an [NSObject], not a
+    // sending [NSObject].
+    try await loadObjects()
+  } // expected-error {{task or actor-isolated value cannot be sent}}
+
+  // Check if we do not mark the block as NS_SWIFT_SENDABLE
+  //
+  // CHECK-LABEL: sil hidden [ossa] @$sSo10ObjCObjectC20regionbasedisolationE12sendObjects2SaySo8NSObjectCGyYaKF : $@convention(method) @async (@guaranteed ObjCObject) -> (@sil_sending @owned Array<NSObject>, @error any Error) {
+  // CHECK: bb0([[SELF:%.*]] : @guaranteed $ObjCObject):
+
+  // Our result.
+  // CHECK: [[RESULT:%.*]] = alloc_stack $Array<NSObject>
+
+  // Our method.
+  // CHECK: [[METHOD:%.*]] = objc_method [[SELF]], #ObjCObject.loadObjects2!foreign : (ObjCObject) -> () async throws -> [NSObject], $@convention(objc_method) (@convention(block) @Sendable (Optional<NSArray>, Optional<NSError>) -> (), ObjCObject) -> ()
+
+  // Begin setting up the unsafe continuation for our method. Importantly note
+  // that [[UNSAFE_CONT]] is Sendable, so we lose any connection from the
+  // continuation addr to any uses of the UnsafeContinuation.
+  //
+  // CHECK: [[CONT:%.*]] = get_async_continuation_addr [throws] Array<NSObject>, [[RESULT]]
+  // CHECK: [[UNSAFE_CONT:%.*]] = struct $UnsafeContinuation<Array<NSObject>, any Error> ([[CONT]])
+
+  // Then prepare the block storage.
+  // CHECK: [[BLOCK_STORAGE:%.*]] = alloc_stack $@block_storage Any
+  // CHECK: [[PROJECT_BLOCK_STORAGE:%.*]] = project_block_storage [[BLOCK_STORAGE]]
+  // CHECK: [[EXISTENTIAL_BLOCK_STORAGE:%.*]] = init_existential_addr [[PROJECT_BLOCK_STORAGE]]
+
+  // Then create a checked continuation from the unsafe continuation.
+  //
+  // CHECK: [[CREATE_CHECKED_CONT:%.*]] = function_ref @$ss34_createCheckedThrowingContinuationyScCyxs5Error_pGSccyxsAB_pGnlF : $@convention(thin) <τ_0_0> (UnsafeContinuation<τ_0_0, any Error>) -> @out CheckedContinuation<τ_0_0, any Error>
+  // CHECK: [[CHECKED_CONT:%.*]] = alloc_stack $CheckedContinuation<Array<NSObject>, any Error>
+  // CHECK: apply [[CREATE_CHECKED_CONT]]<Array<NSObject>>([[CHECKED_CONT]], [[UNSAFE_CONT]])
+
+  // Then place the checked continuation into the block storage and perform a
+  // merge_isolation_region in between the block storage and the result to
+  // propagate that the result and the block storage are apart of the same
+  // region despite the UnsafeContinuation blocking the relation in between
+  // them.
+  //
+  // CHECK: copy_addr [take] [[CHECKED_CONT]] to [init] [[EXISTENTIAL_BLOCK_STORAGE]]
+  // CHECK: merge_isolation_region [[BLOCK_STORAGE]], [[RESULT]]
+
+  // Then create the actual block. NOTE: Since the block is @Sendable, the block
+  // does not propagate regions.
+  //
+  // CHECK: [[COMPLETION_HANDLER_BLOCK:%.*]] = function_ref @$sSo7NSArrayCSgSo7NSErrorCSgIeyBhyy_SaySo8NSObjectCGTz_ : $@convention(c) @Sendable (@inout_aliasable @block_storage Any, Optional<NSArray>, Optional<NSError>) -> ()
+  // CHECK: [[COMPLETION_BLOCK:%.*]] = init_block_storage_header [[BLOCK_STORAGE]], invoke [[COMPLETION_HANDLER_BLOCK]]
+  //
+  // Since the block is @Sendable, it does not propagate the connection in
+  // between self and the block storage when we just call the method. Thus we
+  // need to perform a merge_isolation_region to communicate that the block
+  // storage and self are part of the same region.
+  //
+  // CHECK: merge_isolation_region [[SELF]], [[BLOCK_STORAGE]]
+  //
+  // Then call the method.
+  // CHECK: apply [[METHOD]]([[COMPLETION_BLOCK]], [[SELF]])
+  // CHECK: } // end sil function '$sSo10ObjCObjectC20regionbasedisolationE12sendObjects2SaySo8NSObjectCGyYaKF'
+  func sendObjects2() async throws -> sending [NSObject] {
+    // We emit an error since loadObjects just returns an [NSObject], not a
+    // sending [NSObject].
+    try await loadObjects2()
+  } // expected-error {{task or actor-isolated value cannot be sent}}
+}
+
+@concurrent func useValueConcurrently<T>(_ t: T) async {}
+@MainActor func useValueMainActor<T>(_ t: T) async {}
+nonisolated(nonsending) func useValueNonIsolatedNonSending<T>(_ t: T) async {}
+
+@MainActor func testMainActorMerging(_ y: NSObject) async {
+  let x = ObjCObject()
+  await x.useValue(y)
+  await useValueConcurrently(x)  // expected-error {{sending 'x' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'x' to nonisolated global function 'useValueConcurrently' risks causing data races between nonisolated and main actor-isolated uses}}
+  // expected-ni-ns-note @-2 {{sending main actor-isolated 'x' to @concurrent global function 'useValueConcurrently' risks causing data races between @concurrent and main actor-isolated uses}}
+}
+
+func testTaskLocal(_ y: NSObject) async {
+  let x = ObjCObject()
+  await x.useValue(y)
+  await useValueConcurrently(x) // expected-ni-ns-error {{sending 'x' risks causing data races}}
+  // expected-ni-ns-note @-1 {{sending task-isolated 'x' to @concurrent global function 'useValueConcurrently' risks causing data races between @concurrent and task-isolated uses}}
+
+  // This is not safe since we merge x into y's region making x task
+  // isolated. We then try to send it to a main actor function.
+  await useValueMainActor(x) // expected-error {{sending 'x' risks causing data races}}
+  // expected-note @-1 {{sending task-isolated 'x' to main actor-isolated global function 'useValueMainActor' risks causing data races between main actor-isolated and task-isolated uses}}
+}
+
+actor MyActor {
+  var field = NSObject()
+
+  // This is safe since x.useValue is going to be nonisolated(nonsending) so we
+  // are going to merge x into the actor. And useValueNonIsolatedNonSending
+  // inherits from the context.
+  func test() async {
+    let x = ObjCObject()
+    await x.useValue(field)
+    await useValueNonIsolatedNonSending(x)
+  }  
+}
diff --git a/test/ClangImporter/sdk.swift b/test/ClangImporter/sdk.swift
index cc2e30d79ba33..ce1a7981337ca 100644
--- a/test/ClangImporter/sdk.swift
+++ b/test/ClangImporter/sdk.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/sending.swift b/test/ClangImporter/sending.swift
index a8bc236d9e6b6..188ff210c9fbd 100644
--- a/test/ClangImporter/sending.swift
+++ b/test/ClangImporter/sending.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -swift-version 6 -disable-availability-checking -emit-sil -o /dev/null %s -parse-as-library -enable-experimental-feature SendingArgsAndResults -verify -import-objc-header %S/Inputs/sending.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -swift-version 6 -disable-availability-checking -emit-sil -o /dev/null %s -parse-as-library -enable-experimental-feature SendingArgsAndResults -verify -import-objc-header %S/Inputs/sending.h
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_SendingArgsAndResults
@@ -38,3 +38,18 @@ func funcTestSendingArg() async {
   // expected-note @-1 {{'x' used after being passed as a 'sending' parameter}}
   useValue(x) // expected-note {{access can happen concurrently}}
 }
+
+func funcTestSendingClosureArg() async {
+  sendingWithCompletionHandler { (x: sending NonSendableCStruct) in
+    sendUserDefinedIntoGlobalFunction(x) // expected-error {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{'x' used after being passed as a 'sending' parameter}}
+    useValue(x) // expected-note {{access can happen concurrently}}
+  }
+
+  let x = sendingWithLazyReturn { () -> sending NonSendableCStruct in
+    NonSendableCStruct()
+  }
+  sendUserDefinedIntoGlobalFunction(x) // expected-error {{sending 'x' risks causing data races}}
+  // expected-note @-1 {{'x' used after being passed as a 'sending' parameter}}
+  useValue(x) // expected-note {{access can happen concurrently}}
+}
diff --git a/test/ClangImporter/serialization-search-paths.swift b/test/ClangImporter/serialization-search-paths.swift
index af6b3394eae80..c5cf991438f12 100644
--- a/test/ClangImporter/serialization-search-paths.swift
+++ b/test/ClangImporter/serialization-search-paths.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module-path %t/SerializationHelper.swiftmodule -I %S/Inputs/custom-modules -F %S/Inputs/frameworks -sdk "" -enable-objc-interop -disable-objc-attr-requires-foundation-module %S/Inputs/SerializationHelper.swift
-// RUN: %target-swift-frontend -enable-objc-interop -typecheck -I %t %s -sdk "" -verify
+// RUN: %target-swift-frontend -enable-objc-interop -typecheck -I %t %s -sdk "" -verify -verify-ignore-unrelated
 
 import SerializationHelper
 import Module
diff --git a/test/ClangImporter/simd.swift b/test/ClangImporter/simd.swift
index 69eb614057023..50b67313cfdd1 100644
--- a/test/ClangImporter/simd.swift
+++ b/test/ClangImporter/simd.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -module-name main -typecheck -verify %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -module-name main -typecheck -verify -verify-ignore-unrelated %s
 
 import c_simd
 
diff --git a/test/ClangImporter/static_stdlib.swift b/test/ClangImporter/static_stdlib.swift
new file mode 100644
index 0000000000000..b97d9d8746704
--- /dev/null
+++ b/test/ClangImporter/static_stdlib.swift
@@ -0,0 +1,5 @@
+// RUN: %swift_frontend_plain -parse-stdlib -typecheck %s -dump-clang-diagnostics 2>&1 | %FileCheck %s -check-prefix CHECK-DYNAMIC
+// RUN: %swift_frontend_plain -parse-stdlib -use-static-resource-dir -typecheck %s -dump-clang-diagnostics 2>&1 | %FileCheck %s -check-prefix CHECK-STATIC
+
+// CHECK-DYNAMIC-NOT: clang importer cc1 args: {{.*}} '-D' 'SWIFT_STATIC_STDLIB'
+// CHECK-STATIC: clang importer cc1 args: {{.*}} '-D' 'SWIFT_STATIC_STDLIB'
diff --git a/test/ClangImporter/subclass_existentials.swift b/test/ClangImporter/subclass_existentials.swift
index c7525a48e5716..cc2f5e9571488 100644
--- a/test/ClangImporter/subclass_existentials.swift
+++ b/test/ClangImporter/subclass_existentials.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -o - -primary-file %s -I %S/Inputs/custom-modules/
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -o - -primary-file %s -I %S/Inputs/custom-modules/
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/submodules_scoped.swift b/test/ClangImporter/submodules_scoped.swift
index 6fbafa67f5a71..189b227c472a7 100644
--- a/test/ClangImporter/submodules_scoped.swift
+++ b/test/ClangImporter/submodules_scoped.swift
@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify %s -DCHECK_SCOPING
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated %s -DCHECK_SCOPING
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-module -o %t %s -module-name submodules
 // RUN: echo 'import submodules; let s = "\(x), \(y)"' | %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck - -I %t
 // RUN: echo 'import submodules; let s = "\(x), \(y)"' | not %target-swift-frontend -typecheck - -I %t 2>&1 | %FileCheck -check-prefix=MISSING %s
diff --git a/test/ClangImporter/swift2_warnings.swift b/test/ClangImporter/swift2_warnings.swift
index f7b3152671523..ba96e86463843 100644
--- a/test/ClangImporter/swift2_warnings.swift
+++ b/test/ClangImporter/swift2_warnings.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -I %S/Inputs/custom-modules %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -I %S/Inputs/custom-modules %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/ClangImporter/versioning.swift b/test/ClangImporter/versioning.swift
new file mode 100644
index 0000000000000..5b37e291c1b8c
--- /dev/null
+++ b/test/ClangImporter/versioning.swift
@@ -0,0 +1,9 @@
+// RUN: %target-typecheck-verify-swift %s -I %S/Inputs/custom-modules -enable-experimental-feature ImportMacroAliases
+// XFAIL: *
+
+// REQUIRES: swift_feature_ImportMacroAliases
+
+// expected-no-diagnostics
+
+import RetroactiveVersioning
+let _ = kVersion
diff --git a/test/Compatibility/accessibility.swift b/test/Compatibility/accessibility.swift
index 85461b1ab642a..903ddf6c653cc 100644
--- a/test/Compatibility/accessibility.swift
+++ b/test/Compatibility/accessibility.swift
@@ -1,5 +1,5 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4
-// RUN: %target-typecheck-verify-swift -swift-version 4.2
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 4.2
 
 public protocol PublicProto {
   func publicReq()
diff --git a/test/Concurrency/CaseIterableIsolation.swift b/test/Concurrency/CaseIterableIsolation.swift
index 42c52125e1605..2c5eabb78c17a 100644
--- a/test/Concurrency/CaseIterableIsolation.swift
+++ b/test/Concurrency/CaseIterableIsolation.swift
@@ -1,9 +1,7 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 import StdlibUnittest
 
diff --git a/test/Concurrency/Inputs/implicit_nonisolated_things.swift b/test/Concurrency/Inputs/implicit_nonisolated_things.swift
new file mode 100644
index 0000000000000..ed88a831ada34
--- /dev/null
+++ b/test/Concurrency/Inputs/implicit_nonisolated_things.swift
@@ -0,0 +1,7 @@
+public protocol ImportedSendableProto: Sendable { }
+
+@MainActor public struct ImportedStruct: ImportedSendableProto { }
+
+public struct ImportedOtherStruct { }
+
+public protocol ImportedP { }
diff --git a/test/Concurrency/Inputs/isolated_conformance_other.swift b/test/Concurrency/Inputs/isolated_conformance_other.swift
new file mode 100644
index 0000000000000..8b4fa2e88e697
--- /dev/null
+++ b/test/Concurrency/Inputs/isolated_conformance_other.swift
@@ -0,0 +1,5 @@
+public protocol P {
+  func f()
+}
+
+public protocol PDerived: P {}
diff --git a/test/Concurrency/Reflection/reflect_task.swift b/test/Concurrency/Reflection/reflect_task.swift
index 0e548960d8e1d..3b81b423e5e6d 100644
--- a/test/Concurrency/Reflection/reflect_task.swift
+++ b/test/Concurrency/Reflection/reflect_task.swift
@@ -4,7 +4,7 @@
 // RUN: %target-build-swift %t/reflect_task.swift.o %t/reflect_task.c.o -o %t/reflect_task
 // RUN: %target-codesign %t/reflect_task
 
-// RUN: %target-run %target-swift-reflection-test %t/reflect_task | %FileCheck %s --dump-input=fail
+// RUN: %target-run %target-swift-reflection-test %t/reflect_task | %FileCheck %s --dump-input=always
 
 // REQUIRES: reflection_test_support
 // REQUIRES: executable_test
@@ -28,28 +28,99 @@ func _getCurrentTaskShim() -> UInt
 func add(_ a: UInt, _ b: UInt) async -> UInt {
   if b == 0 {
     reflect(asyncTask: _getCurrentTaskShim())
-    // CHECK: Reflecting an async task.
-    // CHECK: Async task {{0x[0-9a-fA-F]*}}
-
-    // The actual number of chunks we'll get depends on internal implementation
-    // details that we don't want this test to depend on. We'll just make sure
-    // we get at least two, and ignore the details.
-    // CHECK:   Slab pointer {{0x[0-9a-fA-F]*}}
-    // CHECK:     Slab size {{[0-9]{2,}()}}
-    // CHECK:     Chunk at {{0x[0-9a-fA-F]*}} length {{[1-9][0-9]*}} kind {{[0-9]*}}
-    // CHECK:   Slab pointer {{0x[0-9a-fA-F]*}}
-    // CHECK:     Slab size {{[0-9]{2,}()}}
-    // CHECK:     Chunk at {{0x[0-9a-fA-F]*}} length {{[1-9[[0-9]*}} kind {{[0-9]*}}
     return a
   } else {
     return await add(a, b - 1) + 1
   }
 }
 
+func sleepForever() async -> Int {
+  if #available(SwiftStdlib 5.7, *) {
+    try? await Task.sleep(for: .seconds(1_000_000_000))
+    return 42
+  } else {
+    fatalError("This test shouldn't be running against old stdlibs.")
+  }
+}
+
+func testNestedCallsTask() async {
+  reflectionLog(str: "testNestedCallsTask")
+  // CHECK: testNestedCallsTask
+
+  let n = await add(100, 100)
+  reflect(any: n)
+  // CHECK: Reflecting an async task.
+  // CHECK: Async task {{0x[0-9a-fA-F]*}}
+
+  // The actual number of chunks we'll get depends on internal implementation
+  // details that we don't want this test to depend on. We'll just make sure
+  // we get at least two, and ignore the details.
+  // CHECK:   Slab pointer {{0x[0-9a-fA-F]*}}
+  // CHECK:     Slab size {{[0-9]{2,}()}}
+  // CHECK:     Chunk at {{0x[0-9a-fA-F]*}} length {{[1-9][0-9]*}} kind {{[0-9]*}}
+  // CHECK:   Slab pointer {{0x[0-9a-fA-F]*}}
+  // CHECK:     Slab size {{[0-9]{2,}()}}
+  // CHECK:     Chunk at {{0x[0-9a-fA-F]*}} length {{[1-9[[0-9]*}} kind {{[0-9]*}}
+}
+
+// ###HACK: Avoid a race condition by waiting a bit.
+//
+// If we reflect the current task immediately, there is a chance that the
+// runtime is busy manipulating the task structure (e.g. allocating using the
+// task allocator on a child task, or adding a child task) in parallel with
+// the reflection.  This can cause this test to crash when the
+// swift-reflection-test binary asks to read from an uninitialized address.
+//
+// While we could stop the crashing by changing the pipe memory reader to
+// return error codes when it is unable to read memory, that would still
+// result in this test failing randomly.  It's not obvious what the "proper"
+// fix for this should be; the Concurrency runtime isn't going to export
+// anything that would help here.
+func dodgeRaceCondition() async {
+  if #available(SwiftStdlib 5.7, *) {
+    try! await Task.sleep(for: .milliseconds(250))
+  } else {
+    fatalError("This test shouldn't be running against old stdlibs.")
+  }
+}
+
+func testOneAsyncLet() async {
+  reflectionLog(str: "testOneAsyncLet")
+  // CHECK: testOneAsyncLet
+
+  async let alet = sleepForever()
+
+  await dodgeRaceCondition()
+
+  reflect(asyncTask: _getCurrentTaskShim())
+  // CHECK: Async task {{0x[0-9a-fA-F]*}}
+  // CHECK: children = {
+  // CHECK:   Async task {{0x[0-9a-fA-F]*}}
+  // CHECK: }
+}
+
+func testMultipleAsyncLet() async {
+  reflectionLog(str: "testMultipleAsyncLet")
+  // CHECK: testMultipleAsyncLet
+
+  async let alet1 = sleepForever()
+  async let alet2 = sleepForever()
+
+  await dodgeRaceCondition()
+
+  reflect(asyncTask: _getCurrentTaskShim())
+  // CHECK: Async task {{0x[0-9a-fA-F]*}}
+  // CHECK: children = {
+  // CHECK:   Async task {{0x[0-9a-fA-F]*}}
+  // CHECK:   Async task {{0x[0-9a-fA-F]*}}
+  // CHECK: }
+}
+
 @main struct Main {
   static func main() async {
-    let n = await add(100, 100)
-    reflect(any: n)
+    await testNestedCallsTask()
+    await testOneAsyncLet()
+    await testMultipleAsyncLet()
 
     doneReflecting()
   }
diff --git a/test/Concurrency/Runtime/actor_assert_precondition_executor.swift b/test/Concurrency/Runtime/actor_assert_precondition_executor.swift
index 66706fb4b595b..4d349010eb9ec 100644
--- a/test/Concurrency/Runtime/actor_assert_precondition_executor.swift
+++ b/test/Concurrency/Runtime/actor_assert_precondition_executor.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -target %target-swift-5.1-abi-triple -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_bincompat_crash_swift_6_mode.swift b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_bincompat_crash_swift_6_mode.swift
index b29e3816151af..d3f15db2fa259 100644
--- a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_bincompat_crash_swift_6_mode.swift
+++ b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_bincompat_crash_swift_6_mode.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_bincompat_nocrash_legacy_mode.swift b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_bincompat_nocrash_legacy_mode.swift
index 401eb2968bbaf..8b496d96c7a4c 100644
--- a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_bincompat_nocrash_legacy_mode.swift
+++ b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_bincompat_nocrash_legacy_mode.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_dispatch_dispatchMain_swift_6_mode.swift b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_dispatch_dispatchMain_swift_6_mode.swift
index 89a8ff0ce4036..584998be4989d 100644
--- a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_dispatch_dispatchMain_swift_6_mode.swift
+++ b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_dispatch_dispatchMain_swift_6_mode.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_dispatch_swift6_mode.swift b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_dispatch_swift6_mode.swift
index 6270c69618d9b..05a385114e5bc 100644
--- a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_dispatch_swift6_mode.swift
+++ b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_dispatch_swift6_mode.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_main_customExecutorOnMain_swift6_mode.swift b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_main_customExecutorOnMain_swift6_mode.swift
index 2e59ff1b639b0..f836af1d7561b 100644
--- a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_main_customExecutorOnMain_swift6_mode.swift
+++ b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_main_customExecutorOnMain_swift6_mode.swift
@@ -2,8 +2,8 @@
 // RUN: %target-build-swift -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
 
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_swift6_mode.swift b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_swift6_mode.swift
index 9d54adca1994a..486ae5b632df3 100644
--- a/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_swift6_mode.swift
+++ b/test/Concurrency/Runtime/actor_assert_precondition_executor_checkIsolated_swift6_mode.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_assert_precondition_executor_isIsolatingCurrentContext_swift62_mode.swift b/test/Concurrency/Runtime/actor_assert_precondition_executor_isIsolatingCurrentContext_swift62_mode.swift
index 00c68a9b75225..5cd7a28976288 100644
--- a/test/Concurrency/Runtime/actor_assert_precondition_executor_isIsolatingCurrentContext_swift62_mode.swift
+++ b/test/Concurrency/Runtime/actor_assert_precondition_executor_isIsolatingCurrentContext_swift62_mode.swift
@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %import-libdispatch -parse-as-library %s -o %t/a.out
+// RUN: %target-build-swift %import-libdispatch -Xfrontend -disable-availability-checking -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 
@@ -30,7 +30,7 @@ final class IsIsolatingExecutor: SerialExecutor {
     print("called: checkIsolated")
   }
 
-  func isIsolatingCurrentContext() -> Bool {
+  func isIsolatingCurrentContext() -> Bool? {
     print("called: isIsolatingCurrentContext")
     return true
   }
@@ -93,25 +93,22 @@ actor ActorOnIsCheckImplementingExecutor<Ex: SerialExecutor> {
 
 @main struct Main {
   static func main() async {
-    if #available(SwiftStdlib 6.2, *) {
-
-      let hasIsIsolatingCurrentContextExecutor = IsIsolatingExecutor()
-      let justCheckIsolatedExecutor = JustCheckIsolatedExecutor() 
-      
-      print("=== do not crash with executor which implements isIsolatingCurrentContext")
-      let hasIsCheckActor = ActorOnIsCheckImplementingExecutor(on: hasIsIsolatingCurrentContextExecutor)
-      await hasIsCheckActor.checkPreconditionIsolated()
-      // CHECK: Before preconditionIsolated
-      // CHECK-NOT: called: checkIsolated
-      // CHECK: called: isIsolatingCurrentContext
-      // CHECK-NOT: called: checkIsolated
-      // CHECK: After preconditionIsolated
-
-      // CHECK: Before assumeIsolated
-      // CHECK-NOT: called: checkIsolated
-      // CHECK: called: isIsolatingCurrentContext
-      // CHECK-NOT: called: checkIsolated
-      // CHECK: After assumeIsolated
-    }
+    let hasIsIsolatingCurrentContextExecutor = IsIsolatingExecutor()
+    let justCheckIsolatedExecutor = JustCheckIsolatedExecutor()
+
+    print("=== do not crash with executor which implements isIsolatingCurrentContext")
+    let hasIsCheckActor = ActorOnIsCheckImplementingExecutor(on: hasIsIsolatingCurrentContextExecutor)
+    await hasIsCheckActor.checkPreconditionIsolated()
+    // CHECK: Before preconditionIsolated
+    // CHECK-NOT: called: checkIsolated
+    // CHECK: called: isIsolatingCurrentContext
+    // CHECK-NOT: called: checkIsolated
+    // CHECK: After preconditionIsolated
+
+    // CHECK: Before assumeIsolated
+    // CHECK-NOT: called: checkIsolated
+    // CHECK: called: isIsolatingCurrentContext
+    // CHECK-NOT: called: checkIsolated
+    // CHECK: After assumeIsolated
   }
 }
diff --git a/test/Concurrency/Runtime/actor_assert_precondition_executor_not_implemented_isIsolatingCurrentContext_swift62_mode.swift b/test/Concurrency/Runtime/actor_assert_precondition_executor_not_implemented_isIsolatingCurrentContext_swift62_mode.swift
index 693075078cefc..05f79173eabfd 100644
--- a/test/Concurrency/Runtime/actor_assert_precondition_executor_not_implemented_isIsolatingCurrentContext_swift62_mode.swift
+++ b/test/Concurrency/Runtime/actor_assert_precondition_executor_not_implemented_isIsolatingCurrentContext_swift62_mode.swift
@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %import-libdispatch -parse-as-library %s -o %t/a.out
+// RUN: %target-build-swift %import-libdispatch -Xfrontend -disable-availability-checking -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 
@@ -30,7 +30,7 @@ final class IsIsolatingExecutor: SerialExecutor {
     print("called: checkIsolated")
   }
 
-  func isIsolatingCurrentContext() -> Bool {
+  func isIsolatingCurrentContext() -> Bool? {
     print("called: isIsolatingCurrentContext")
     return true
   }
@@ -80,25 +80,22 @@ actor ActorOnIsCheckImplementingExecutor<Ex: SerialExecutor> {
 
 @main struct Main {
   static func main() async {
-    if #available(SwiftStdlib 6.2, *) {
-
-      let hasIsIsolatingCurrentContextExecutor = IsIsolatingExecutor()
-      let justCheckIsolatedExecutor = JustCheckIsolatedExecutor() 
-      
-      print("do checkIsolated with executor which does NOT implement isIsolatingCurrentContext")
-      let checkIsolatedActor = ActorOnIsCheckImplementingExecutor(on: justCheckIsolatedExecutor)
-      await checkIsolatedActor.checkPreconditionIsolated()
-      // CHECK: Before preconditionIsolated
-      // CHECK-NOT: called: isIsolatingCurrentContext
-      // CHECK: called: checkIsolated
-      // CHECK-NOT: called: isIsolatingCurrentContext
-      // CHECK: After preconditionIsolated
-
-      // CHECK: Before assumeIsolated
-      // CHECK-NOT: called: isIsolatingCurrentContext
-      // CHECK: called: checkIsolated
-      // CHECK-NOT: called: isIsolatingCurrentContext
-      // CHECK: After assumeIsolated
-    }
+    let hasIsIsolatingCurrentContextExecutor = IsIsolatingExecutor()
+    let justCheckIsolatedExecutor = JustCheckIsolatedExecutor()
+
+    print("do checkIsolated with executor which does NOT implement isIsolatingCurrentContext")
+    let checkIsolatedActor = ActorOnIsCheckImplementingExecutor(on: justCheckIsolatedExecutor)
+    await checkIsolatedActor.checkPreconditionIsolated()
+    // CHECK: Before preconditionIsolated
+    // CHECK-NOT: called: isIsolatingCurrentContext
+    // CHECK: called: checkIsolated
+    // CHECK-NOT: called: isIsolatingCurrentContext
+    // CHECK: After preconditionIsolated
+
+    // CHECK: Before assumeIsolated
+    // CHECK-NOT: called: isIsolatingCurrentContext
+    // CHECK: called: checkIsolated
+    // CHECK-NOT: called: isIsolatingCurrentContext
+    // CHECK: After assumeIsolated
   }
 }
diff --git a/test/Concurrency/Runtime/actor_assume_executor.swift b/test/Concurrency/Runtime/actor_assume_executor.swift
index b885f520bec38..0536a7a0df5bf 100644
--- a/test/Concurrency/Runtime/actor_assume_executor.swift
+++ b/test/Concurrency/Runtime/actor_assume_executor.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -target %target-swift-5.1-abi-triple -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
@@ -17,7 +17,7 @@
 import StdlibUnittest
 
 func checkAssumeMainActor(echo: MainActorEcho) /* synchronous! */ {
-  // Echo.get("any") // error: main actor isolated, cannot perform async call here
+  // Echo.get("any") // error: MainActor isolated, cannot perform async call here
   MainActor.assumeIsolated {
     let input = "example"
     let got = echo.get(input)
diff --git a/test/Concurrency/Runtime/actor_counters.swift b/test/Concurrency/Runtime/actor_counters.swift
index 5749f6012db42..26c19a1143839 100644
--- a/test/Concurrency/Runtime/actor_counters.swift
+++ b/test/Concurrency/Runtime/actor_counters.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -sil-verify-all -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library)
+// RUN: %target-run-simple-swift( -Xfrontend -sil-verify-all -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_counters_freestanding.swift b/test/Concurrency/Runtime/actor_counters_freestanding.swift
index 827e94356115c..afe2a5359c870 100644
--- a/test/Concurrency/Runtime/actor_counters_freestanding.swift
+++ b/test/Concurrency/Runtime/actor_counters_freestanding.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -sil-verify-all -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library)
+// RUN: %target-run-simple-swift( -Xfrontend -sil-verify-all -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_deinit_escaping_self.swift b/test/Concurrency/Runtime/actor_deinit_escaping_self.swift
index dd3e23d0aef39..13879a163b1a2 100644
--- a/test/Concurrency/Runtime/actor_deinit_escaping_self.swift
+++ b/test/Concurrency/Runtime/actor_deinit_escaping_self.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-future-triple %import-libdispatch -parse-as-library)
+// RUN: %target-run-simple-swift( -target %target-future-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: libdispatch
diff --git a/test/Concurrency/Runtime/actor_detach.swift b/test/Concurrency/Runtime/actor_detach.swift
index b7b178a28bd38..22b65d6e33b7d 100644
--- a/test/Concurrency/Runtime/actor_detach.swift
+++ b/test/Concurrency/Runtime/actor_detach.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_dynamic_subclass.swift b/test/Concurrency/Runtime/actor_dynamic_subclass.swift
index 83a73fce14bfe..c02ba70cea761 100644
--- a/test/Concurrency/Runtime/actor_dynamic_subclass.swift
+++ b/test/Concurrency/Runtime/actor_dynamic_subclass.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library)
+// RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_init.swift b/test/Concurrency/Runtime/actor_init.swift
index c40acc77dec4b..f1b5ce6134da5 100644
--- a/test/Concurrency/Runtime/actor_init.swift
+++ b/test/Concurrency/Runtime/actor_init.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(%import-libdispatch -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift(%import-libdispatch -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_isIsolatingCurrentContext.swift b/test/Concurrency/Runtime/actor_isIsolatingCurrentContext.swift
new file mode 100644
index 0000000000000..d5667edeb4c97
--- /dev/null
+++ b/test/Concurrency/Runtime/actor_isIsolatingCurrentContext.swift
@@ -0,0 +1,130 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %import-libdispatch -Xfrontend -disable-availability-checking -parse-as-library %s -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: concurrency_runtime
+
+// REQUIRES: libdispatch
+
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: back_deploy_concurrency
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: freestanding
+
+@available(SwiftStdlib 6.2, *)
+final class IsIsolatingExecutor: SerialExecutor {
+  init() {}
+
+  func enqueue(_ job: consuming ExecutorJob) {
+    job.runSynchronously(on: self.asUnownedSerialExecutor())
+  }
+
+  func asUnownedSerialExecutor() -> UnownedSerialExecutor {
+    UnownedSerialExecutor(ordinary: self)
+  }
+
+  func checkIsolated() {
+    print("called: checkIsolated")
+  }
+
+  func isIsolatingCurrentContext() -> Bool? {
+    print("called: isIsolatingCurrentContext")
+    return true
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+final class UnknownIfIsIsolatingExecutor: SerialExecutor {
+  init() {}
+
+  func enqueue(_ job: consuming ExecutorJob) {
+    job.runSynchronously(on: self.asUnownedSerialExecutor())
+  }
+
+  func asUnownedSerialExecutor() -> UnownedSerialExecutor {
+    UnownedSerialExecutor(ordinary: self)
+  }
+
+  func checkIsolated() {
+    print("called: checkIsolated")
+  }
+
+  func isIsolatingCurrentContext() -> Bool? {
+    print("called: isIsolatingCurrentContext; return nil")
+    return nil
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+final class NoChecksImplementedExecutor: SerialExecutor {
+  init() {}
+
+  func enqueue(_ job: consuming ExecutorJob) {
+    job.runSynchronously(on: self.asUnownedSerialExecutor())
+  }
+
+  func asUnownedSerialExecutor() -> UnownedSerialExecutor {
+    UnownedSerialExecutor(ordinary: self)
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+final class JustCheckIsolatedExecutor: SerialExecutor {
+  init() {}
+
+  func enqueue(_ job: consuming ExecutorJob) {
+    job.runSynchronously(on: self.asUnownedSerialExecutor())
+  }
+
+  func asUnownedSerialExecutor() -> UnownedSerialExecutor {
+    UnownedSerialExecutor(ordinary: self)
+  }
+
+  func checkIsolated() {
+    print("called: checkIsolated")
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+actor ActorOnIsCheckImplementingExecutor<Ex: SerialExecutor> {
+  let executor: Ex
+
+  init(on executor: Ex) {
+    self.executor = executor
+  }
+
+  nonisolated var unownedExecutor: UnownedSerialExecutor {
+    self.executor.asUnownedSerialExecutor()
+  }
+
+  func checkIsIsolatingCurrentContext() async -> Bool? {
+    executor.isIsolatingCurrentContext()
+  }
+}
+
+@main struct Main {
+  static func main() async {
+    let hasIsIsolatingCurrentContextExecutor = IsIsolatingExecutor()
+    let hasIsCheckActor = ActorOnIsCheckImplementingExecutor(on: hasIsIsolatingCurrentContextExecutor)
+    let unknownIsIsolatingActor = ActorOnIsCheckImplementingExecutor(on: UnknownIfIsIsolatingExecutor())
+
+    let anyActor: any Actor = hasIsCheckActor
+
+    anyActor.withSerialExecutor { se in
+      let outside = se.isIsolatingCurrentContext()
+      assert(outside == true) // This is just a mock executor impl that always returns "true" (it is lying)
+      // CHECK: called: isIsolatingCurrentContext
+    }
+
+    let inside = await hasIsCheckActor.checkIsIsolatingCurrentContext()
+    assert(inside == true)
+    // CHECK: called: isIsolatingCurrentContext
+
+    _ = unknownIsIsolatingActor.preconditionIsolated()
+    // CHECK: called: isIsolatingCurrentContext; return nil
+    // CHECK: called: checkIsolated
+  }
+}
diff --git a/test/Concurrency/Runtime/actor_keypaths.swift b/test/Concurrency/Runtime/actor_keypaths.swift
index dcf601158760c..be64cfa2513e1 100644
--- a/test/Concurrency/Runtime/actor_keypaths.swift
+++ b/test/Concurrency/Runtime/actor_keypaths.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/actor_recursive_deinit.swift b/test/Concurrency/Runtime/actor_recursive_deinit.swift
index 2a05c23a23894..bedad75ba3501 100644
--- a/test/Concurrency/Runtime/actor_recursive_deinit.swift
+++ b/test/Concurrency/Runtime/actor_recursive_deinit.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-target %target-future-triple -parse-stdlib -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift(-target %target-future-triple -parse-stdlib -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async.swift b/test/Concurrency/Runtime/async.swift
index 9360f32c392d1..741fc3419b5de 100644
--- a/test/Concurrency/Runtime/async.swift
+++ b/test/Concurrency/Runtime/async.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_initializer.swift b/test/Concurrency/Runtime/async_initializer.swift
index 1e2596d169ac2..feb0c8b937a7b 100644
--- a/test/Concurrency/Runtime/async_initializer.swift
+++ b/test/Concurrency/Runtime/async_initializer.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-parse-as-library  -target %target-swift-5.1-abi-triple) | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library  -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_let_fibonacci.swift b/test/Concurrency/Runtime/async_let_fibonacci.swift
index 10d6075ae1ad4..8e02cfd96aecd 100644
--- a/test/Concurrency/Runtime/async_let_fibonacci.swift
+++ b/test/Concurrency/Runtime/async_let_fibonacci.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_let_throw_completion_order.swift b/test/Concurrency/Runtime/async_let_throw_completion_order.swift
index 504d3f69506e4..ff87dc71330b3 100644
--- a/test/Concurrency/Runtime/async_let_throw_completion_order.swift
+++ b/test/Concurrency/Runtime/async_let_throw_completion_order.swift
@@ -1,5 +1,7 @@
 // rdar://81481317
 // RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 
diff --git a/test/Concurrency/Runtime/async_let_throws.swift b/test/Concurrency/Runtime/async_let_throws.swift
index 21fb512b2f382..bd3089dcf271e 100644
--- a/test/Concurrency/Runtime/async_let_throws.swift
+++ b/test/Concurrency/Runtime/async_let_throws.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_parameter_pack.swift b/test/Concurrency/Runtime/async_parameter_pack.swift
new file mode 100644
index 0000000000000..d1d261ffb1e8a
--- /dev/null
+++ b/test/Concurrency/Runtime/async_parameter_pack.swift
@@ -0,0 +1,24 @@
+// RUN: %target-run-simple-swift( -target %target-swift-5.9-abi-triple)
+// RUN: %target-run-simple-swift( -target %target-swift-5.9-abi-triple -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// UNSUPPORTED: back_deployment_runtime || use_os_stdlib
+
+protocol P {
+  associatedtype A
+  var a: A { get }
+}
+
+func f<each T: P>(_ t: repeat each T) async -> (repeat (each T).A) {
+  let x = (repeat (each t).a)
+  return x
+}
+
+struct S: P {
+  var a: String { "" }
+}
+
+_ = await f()
+_ = await f(S())
+_ = await f(S(), S())
diff --git a/test/Concurrency/Runtime/async_properties_actor.swift b/test/Concurrency/Runtime/async_properties_actor.swift
index 8e0419a81e0f9..ebb2f4809b839 100644
--- a/test/Concurrency/Runtime/async_properties_actor.swift
+++ b/test/Concurrency/Runtime/async_properties_actor.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-parse-as-library -Xfrontend -enable-copy-propagation -Xfrontend -enable-lexical-lifetimes=false  -target %target-swift-5.1-abi-triple) | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library -Xfrontend -enable-copy-propagation -Xfrontend -enable-lexical-lifetimes=false  -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_sequence.swift b/test/Concurrency/Runtime/async_sequence.swift
index 7683b9021dd27..b48898b6cb9fa 100644
--- a/test/Concurrency/Runtime/async_sequence.swift
+++ b/test/Concurrency/Runtime/async_sequence.swift
@@ -1,14 +1,12 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 
-// rdar://76038845
 // REQUIRES: concurrency_runtime
 
-// TODO: This crashes on linux for some strange reason
-// REQUIRES: OS=macosx
-
 import StdlibUnittest
 
 // Utility functions for closure based operators to force them into throwing
diff --git a/test/Concurrency/Runtime/async_stream.swift b/test/Concurrency/Runtime/async_stream.swift
index 7f54de2165632..59976a67f19ad 100644
--- a/test/Concurrency/Runtime/async_stream.swift
+++ b/test/Concurrency/Runtime/async_stream.swift
@@ -1,5 +1,7 @@
 // RUN: %target-typecheck-verify-swift -strict-concurrency=complete -disable-availability-checking -parse-as-library
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library)
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
@@ -435,6 +437,24 @@ class NotSendable {}
         expectTrue(expectation.fulfilled)
       }
 
+      tests.test("continuation equality") {
+        let (_, continuation1) = AsyncStream<Int>.makeStream()
+        let (_, continuation2) = AsyncStream<Int>.makeStream()
+        expectTrue(continuation1 == continuation1)
+        expectTrue(continuation1 != continuation2)
+        expectTrue(continuation1.hashValue == continuation1.hashValue)
+        expectTrue(continuation1.hashValue != continuation2.hashValue)
+      }
+
+      tests.test("throwing continuation equality") {
+        let (_, continuation1) = AsyncThrowingStream<Int, Error>.makeStream()
+        let (_, continuation2) = AsyncThrowingStream<Int, Error>.makeStream()
+        expectTrue(continuation1 == continuation1)
+        expectTrue(continuation1 != continuation2)
+        expectTrue(continuation1.hashValue == continuation1.hashValue)
+        expectTrue(continuation1.hashValue != continuation2.hashValue)
+      }
+
       // MARK: - Multiple consumers
 
       tests.test("finish behavior with multiple consumers") {
diff --git a/test/Concurrency/Runtime/async_task_async_let_child_cancel.swift b/test/Concurrency/Runtime/async_task_async_let_child_cancel.swift
index 9afa4aa262507..a2362c7c5736f 100644
--- a/test/Concurrency/Runtime/async_task_async_let_child_cancel.swift
+++ b/test/Concurrency/Runtime/async_task_async_let_child_cancel.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_cancellation_early.swift b/test/Concurrency/Runtime/async_task_cancellation_early.swift
index 88c626c962d7a..60d6ff6b68d74 100644
--- a/test/Concurrency/Runtime/async_task_cancellation_early.swift
+++ b/test/Concurrency/Runtime/async_task_cancellation_early.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_cancellation_taskGroup.swift b/test/Concurrency/Runtime/async_task_cancellation_taskGroup.swift
index f78437db7884c..2eaeaced17994 100644
--- a/test/Concurrency/Runtime/async_task_cancellation_taskGroup.swift
+++ b/test/Concurrency/Runtime/async_task_cancellation_taskGroup.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_cancellation_while_running.swift b/test/Concurrency/Runtime/async_task_cancellation_while_running.swift
index fd9da7e007dcd..c768fa3f7a51a 100644
--- a/test/Concurrency/Runtime/async_task_cancellation_while_running.swift
+++ b/test/Concurrency/Runtime/async_task_cancellation_while_running.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_detach.swift b/test/Concurrency/Runtime/async_task_detach.swift
index 60262638a9824..0a951eab59fc4 100644
--- a/test/Concurrency/Runtime/async_task_detach.swift
+++ b/test/Concurrency/Runtime/async_task_detach.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_executor_and_serial_executor_both_executor.swift b/test/Concurrency/Runtime/async_task_executor_and_serial_executor_both_executor.swift
index a9873a66213bc..8fe903ebdb3cb 100644
--- a/test/Concurrency/Runtime/async_task_executor_and_serial_executor_both_executor.swift
+++ b/test/Concurrency/Runtime/async_task_executor_and_serial_executor_both_executor.swift
@@ -3,16 +3,17 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %import-libdispatch %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %import-libdispatch %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %import-libdispatch %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %import-libdispatch %t/a.out
 
 // TODO: Need to find out how to combine %env- and %target-run and %import-libdispatch reliably.
 // UNSUPPORTED: OS=linux-gnu
+// UNSUPPORTED: OS=freebsd
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
 // REQUIRES: libdispatch
-// 
+//
 // REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
diff --git a/test/Concurrency/Runtime/async_task_executor_and_serial_executor_nonisolated_async_func_legacy.swift b/test/Concurrency/Runtime/async_task_executor_and_serial_executor_nonisolated_async_func_legacy.swift
index 6da712165e618..bcbf905b80dba 100644
--- a/test/Concurrency/Runtime/async_task_executor_and_serial_executor_nonisolated_async_func_legacy.swift
+++ b/test/Concurrency/Runtime/async_task_executor_and_serial_executor_nonisolated_async_func_legacy.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_executor_and_serial_executor_nonisolated_async_func_swift6.swift b/test/Concurrency/Runtime/async_task_executor_and_serial_executor_nonisolated_async_func_swift6.swift
index 5ad33b658233f..b342c4b5305cf 100644
--- a/test/Concurrency/Runtime/async_task_executor_and_serial_executor_nonisolated_async_func_swift6.swift
+++ b/test/Concurrency/Runtime/async_task_executor_and_serial_executor_nonisolated_async_func_swift6.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_executor_default_actor_funcs.swift b/test/Concurrency/Runtime/async_task_executor_default_actor_funcs.swift
index cb75f8ecb105b..73eb1d0644fd3 100644
--- a/test/Concurrency/Runtime/async_task_executor_default_actor_funcs.swift
+++ b/test/Concurrency/Runtime/async_task_executor_default_actor_funcs.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library )
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library  -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_executor_nonisolated_async_func.swift b/test/Concurrency/Runtime/async_task_executor_nonisolated_async_func.swift
index a5a0da5954030..e652914b4d3c9 100644
--- a/test/Concurrency/Runtime/async_task_executor_nonisolated_async_func.swift
+++ b/test/Concurrency/Runtime/async_task_executor_nonisolated_async_func.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library )
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library  -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_executor_nsobject.swift b/test/Concurrency/Runtime/async_task_executor_nsobject.swift
index d652f7d246f01..5e06580942017 100644
--- a/test/Concurrency/Runtime/async_task_executor_nsobject.swift
+++ b/test/Concurrency/Runtime/async_task_executor_nsobject.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library )
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library  -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
@@ -22,7 +24,7 @@ import Darwin
 // This test specifically checks that our reference counting accounts for existence of
 // objective-c types as TaskExecutors -- which was a bug where we'd swift_release
 // obj-c excecutors by accident (rdar://131151645).
-final class NSQueueTaskExecutor: NSData, TaskExecutor, SchedulableExecutor, @unchecked Sendable {
+final class NSQueueTaskExecutor: NSData, TaskExecutor, SchedulingExecutor, @unchecked Sendable {
   public func enqueue(_ _job: consuming ExecutorJob) {
     let job = UnownedJob(_job)
     DispatchQueue.main.async {
@@ -35,7 +37,7 @@ final class NSQueueTaskExecutor: NSData, TaskExecutor, SchedulableExecutor, @unc
                                 tolerance: C.Duration? = nil,
                                 clock: C) {
     // Convert to `Swift.Duration`
-    let duration = clock.convert(from: delay)!
+    let duration = delay as! Swift.Duration
 
     // Now turn that into nanoseconds
     let (seconds, attoseconds) = duration.components
diff --git a/test/Concurrency/Runtime/async_task_executor_structured_concurrency.swift b/test/Concurrency/Runtime/async_task_executor_structured_concurrency.swift
index 3d2805bf8274b..4a7967d189b3d 100644
--- a/test/Concurrency/Runtime/async_task_executor_structured_concurrency.swift
+++ b/test/Concurrency/Runtime/async_task_executor_structured_concurrency.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library )
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library  -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_executor_unstructured_task_ownership.swift b/test/Concurrency/Runtime/async_task_executor_unstructured_task_ownership.swift
index ae76d31dc55ee..85e939d8bf068 100644
--- a/test/Concurrency/Runtime/async_task_executor_unstructured_task_ownership.swift
+++ b/test/Concurrency/Runtime/async_task_executor_unstructured_task_ownership.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library ) | %FileCheck %s
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library  -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_executor_withExecutor.swift b/test/Concurrency/Runtime/async_task_executor_withExecutor.swift
index f714c2a9e2300..51bbc08ea1b8d 100644
--- a/test/Concurrency/Runtime/async_task_executor_withExecutor.swift
+++ b/test/Concurrency/Runtime/async_task_executor_withExecutor.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library )
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library  -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_handle_cancellation.swift b/test/Concurrency/Runtime/async_task_handle_cancellation.swift
index 822abd6c3278f..7ff6e6b3d1e73 100644
--- a/test/Concurrency/Runtime/async_task_handle_cancellation.swift
+++ b/test/Concurrency/Runtime/async_task_handle_cancellation.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_locals_async_let.swift b/test/Concurrency/Runtime/async_task_locals_async_let.swift
index aa6b980d0e7e5..9089f85037bec 100644
--- a/test/Concurrency/Runtime/async_task_locals_async_let.swift
+++ b/test/Concurrency/Runtime/async_task_locals_async_let.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_locals_basic.swift b/test/Concurrency/Runtime/async_task_locals_basic.swift
index b8cde99791d34..58af953c3868a 100644
--- a/test/Concurrency/Runtime/async_task_locals_basic.swift
+++ b/test/Concurrency/Runtime/async_task_locals_basic.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -parse-as-library %import-libdispatch) | %FileCheck %s
+// RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -parse-as-library %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_locals_copy_to_async.swift b/test/Concurrency/Runtime/async_task_locals_copy_to_async.swift
index bb9aaae6b8538..fb97b9ab1abcd 100644
--- a/test/Concurrency/Runtime/async_task_locals_copy_to_async.swift
+++ b/test/Concurrency/Runtime/async_task_locals_copy_to_async.swift
@@ -1,5 +1,7 @@
 // REQUIRES: rdar80824152
 // RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch) | %FileCheck %s
+// RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_locals_copy_to_sync.swift b/test/Concurrency/Runtime/async_task_locals_copy_to_sync.swift
index 9ebaf08c40916..301f07c49f265 100644
--- a/test/Concurrency/Runtime/async_task_locals_copy_to_sync.swift
+++ b/test/Concurrency/Runtime/async_task_locals_copy_to_sync.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch) | %FileCheck %s
+// RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_locals_groups.swift b/test/Concurrency/Runtime/async_task_locals_groups.swift
index 02ee42b2f855e..d4ff7ae92950e 100644
--- a/test/Concurrency/Runtime/async_task_locals_groups.swift
+++ b/test/Concurrency/Runtime/async_task_locals_groups.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch) | %FileCheck %s
+// RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_locals_in_task_group_may_need_to_copy.swift b/test/Concurrency/Runtime/async_task_locals_in_task_group_may_need_to_copy.swift
index 896c7bc7f2ac8..4e4c752ea0a88 100644
--- a/test/Concurrency/Runtime/async_task_locals_in_task_group_may_need_to_copy.swift
+++ b/test/Concurrency/Runtime/async_task_locals_in_task_group_may_need_to_copy.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -Xfrontend -strict-concurrency=complete -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -Xfrontend -strict-concurrency=complete -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_locals_isolated_deinit.swift b/test/Concurrency/Runtime/async_task_locals_isolated_deinit.swift
index 94fa6e7d62976..e629703909ec2 100644
--- a/test/Concurrency/Runtime/async_task_locals_isolated_deinit.swift
+++ b/test/Concurrency/Runtime/async_task_locals_isolated_deinit.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -plugin-path %swift-plugin-dir -target %target-future-triple -parse-stdlib %import-libdispatch %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %t/a.out
 
 // REQUIRES: libdispatch
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/async_task_locals_prevent_illegal_use_but_specific_case_is_ok.swift b/test/Concurrency/Runtime/async_task_locals_prevent_illegal_use_but_specific_case_is_ok.swift
index 1944c168542f0..04b83fd1d225a 100644
--- a/test/Concurrency/Runtime/async_task_locals_prevent_illegal_use_but_specific_case_is_ok.swift
+++ b/test/Concurrency/Runtime/async_task_locals_prevent_illegal_use_but_specific_case_is_ok.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_locals_synchronous_bind.swift b/test/Concurrency/Runtime/async_task_locals_synchronous_bind.swift
index b5f181c49ae95..1ea38a65b000b 100644
--- a/test/Concurrency/Runtime/async_task_locals_synchronous_bind.swift
+++ b/test/Concurrency/Runtime/async_task_locals_synchronous_bind.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_locals_wrapper.swift b/test/Concurrency/Runtime/async_task_locals_wrapper.swift
index 7d70843920795..d407efca6d18e 100644
--- a/test/Concurrency/Runtime/async_task_locals_wrapper.swift
+++ b/test/Concurrency/Runtime/async_task_locals_wrapper.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_naming.swift b/test/Concurrency/Runtime/async_task_naming.swift
index 7b597a1271dd6..5dd33fdb919a5 100644
--- a/test/Concurrency/Runtime/async_task_naming.swift
+++ b/test/Concurrency/Runtime/async_task_naming.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking) | %FileCheck %s
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_priority_current.swift b/test/Concurrency/Runtime/async_task_priority_current.swift
index 58b0f6fc40967..cae419fcf5753 100644
--- a/test/Concurrency/Runtime/async_task_priority_current.swift
+++ b/test/Concurrency/Runtime/async_task_priority_current.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck --dump-input=always %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck --dump-input=always %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_task_sleep.swift b/test/Concurrency/Runtime/async_task_sleep.swift
index ec242a1132c28..926fae5aa0626 100644
--- a/test/Concurrency/Runtime/async_task_sleep.swift
+++ b/test/Concurrency/Runtime/async_task_sleep.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
@@ -14,11 +16,14 @@ import Dispatch
 @available(SwiftStdlib 5.1, *)
 @main struct Main {
   static let pause = 500_000_000 // 500ms
-  
+
   static func main() async {
     await testSleepDuration()
     await testSleepDoesNotBlock()
     await testSleepHuge()
+    if #available(SwiftStdlib 5.7, *) {
+      await testSleepNegative()
+    }
   }
 
   static func testSleepDuration() async {
@@ -34,7 +39,7 @@ import Dispatch
 
   static func testSleepDoesNotBlock() async {
     // FIXME: Should run on main executor
-    let task = detach {
+    let task = Task.detached {
       print("Run first")
     }
 
@@ -50,10 +55,10 @@ import Dispatch
   static func testSleepHuge() async {
     // Make sure nanoseconds values about Int64.max don't get interpreted as
     // negative and fail to sleep.
-    let task1 = detach {
+    let task1 = Task.detached {
       try await Task.sleep(nanoseconds: UInt64(Int64.max) + 1)
     }
-    let task2 = detach {
+    let task2 = Task.detached {
       try await Task.sleep(nanoseconds: UInt64.max)
     }
 
@@ -73,4 +78,28 @@ import Dispatch
       fatalError("Sleep 2 completed early.")
     } catch {}
   }
+
+  @available(SwiftStdlib 5.7, *)
+  static func testSleepNegative() async {
+    // Make sure that "negative" times don't cause us to sleep forever
+    let negativeDuration = Duration(secondsComponent: -60,
+                                    attosecondsComponent: 0)
+    let negativeTime = unsafe unsafeBitCast(negativeDuration,
+                                            to: ContinuousClock.Instant.self)
+
+    let task = Task.detached {
+      try await Task.sleep(until: negativeTime)
+    }
+
+    try! await Task.sleep(nanoseconds: UInt64(pause))
+
+    task.cancel()
+
+    // The sleep should complete; if they throw, this is a failure.
+    do {
+      _ = try await task.value
+    } catch {
+      fatalError("Sleep tried to wait for a negative time")
+    }
+  }
 }
diff --git a/test/Concurrency/Runtime/async_task_sleep_cancel.swift b/test/Concurrency/Runtime/async_task_sleep_cancel.swift
index 245f960f792f1..03429ad31caec 100644
--- a/test/Concurrency/Runtime/async_task_sleep_cancel.swift
+++ b/test/Concurrency/Runtime/async_task_sleep_cancel.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
diff --git a/test/Concurrency/Runtime/async_task_withUnsafeCurrentTask.swift b/test/Concurrency/Runtime/async_task_withUnsafeCurrentTask.swift
index 5aa0983468caf..5547e4d95e8b5 100644
--- a/test/Concurrency/Runtime/async_task_withUnsafeCurrentTask.swift
+++ b/test/Concurrency/Runtime/async_task_withUnsafeCurrentTask.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library) 2>&1 | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  2>&1 | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: swift_task_debug_log
diff --git a/test/Concurrency/Runtime/async_task_yield.swift b/test/Concurrency/Runtime/async_task_yield.swift
index 07110f890ad94..34ae1e2db00b4 100644
--- a/test/Concurrency/Runtime/async_task_yield.swift
+++ b/test/Concurrency/Runtime/async_task_yield.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library)
+// RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_addUnlessCancelled.swift b/test/Concurrency/Runtime/async_taskgroup_addUnlessCancelled.swift
new file mode 100644
index 0000000000000..da68ea317426e
--- /dev/null
+++ b/test/Concurrency/Runtime/async_taskgroup_addUnlessCancelled.swift
@@ -0,0 +1,61 @@
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+
+// REQUIRES: concurrency_runtime
+// UNSUPPORTED: back_deployment_runtime
+
+@available(SwiftStdlib 6.0, *)
+func test_withTaskGroup_addUnlessCancelled() async throws {
+  let task = Task {
+    await withTaskGroup(of: Void.self) { group in
+      print("Inner: Sleep...")
+      try? await Task.sleep(for: .seconds(60)) // we'll never actually wait 10 seconds, as this will be woken up by cancel
+      print("Inner: Task.isCancelled: \(Task.isCancelled)")
+
+      let added = group.addTaskUnlessCancelled {
+        print("Added Task! Child Task.isCancelled: \(Task.isCancelled)")
+      }
+      print("Inner: Task added = \(added)")  // CHECK: Inner: Task added = false
+    }
+  }
+
+  print("Outer: Cancel!")
+  task.cancel()
+  print("Outer: Cancelled")
+
+  await task.value
+}
+
+@available(SwiftStdlib 6.0, *)
+func test_withDiscardingTaskGroup_addUnlessCancelled() async throws {
+  let task = Task {
+    await withDiscardingTaskGroup { group in
+      print("Inner: Sleep...")
+      try? await Task.sleep(for: .seconds(60)) // we'll never actually wait 10 seconds, as this will be woken up by cancel
+      print("Inner: Task.isCancelled: \(Task.isCancelled)")
+
+      let added = group.addTaskUnlessCancelled {
+        print("Added Task! Child Task.isCancelled: \(Task.isCancelled)")
+      }
+      print("Inner: Task added = \(added)")  // CHECK: Inner: Task added = false
+    }
+  }
+
+  print("Outer: Cancel!")
+  task.cancel()
+  print("Outer: Cancelled")
+
+  await task.value
+}
+
+@available(SwiftStdlib 6.0, *)
+@main struct Main {
+  static func main() async {
+    try! await test_withTaskGroup_addUnlessCancelled()
+    try! await test_withDiscardingTaskGroup_addUnlessCancelled()
+  }
+}
diff --git a/test/Concurrency/Runtime/async_taskgroup_asynciterator_semantics.swift b/test/Concurrency/Runtime/async_taskgroup_asynciterator_semantics.swift
index 9abefe8417a59..616e7e790d6fd 100644
--- a/test/Concurrency/Runtime/async_taskgroup_asynciterator_semantics.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_asynciterator_semantics.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_cancelAll_only_specific_group.swift b/test/Concurrency/Runtime/async_taskgroup_cancelAll_only_specific_group.swift
index 1ed9c55d0d84a..9c8895ec1802c 100644
--- a/test/Concurrency/Runtime/async_taskgroup_cancelAll_only_specific_group.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_cancelAll_only_specific_group.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_cancel_parent_affects_group.swift b/test/Concurrency/Runtime/async_taskgroup_cancel_parent_affects_group.swift
index 4699feb3726ad..267572f167334 100644
--- a/test/Concurrency/Runtime/async_taskgroup_cancel_parent_affects_group.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_cancel_parent_affects_group.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_cancel_then_completions.swift b/test/Concurrency/Runtime/async_taskgroup_cancel_then_completions.swift
index 640155502d2b8..18ef79a1a1d06 100644
--- a/test/Concurrency/Runtime/async_taskgroup_cancel_then_completions.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_cancel_then_completions.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_cancel_then_spawn.swift b/test/Concurrency/Runtime/async_taskgroup_cancel_then_spawn.swift
index d97d5330ea0f2..c313a37c56cd1 100644
--- a/test/Concurrency/Runtime/async_taskgroup_cancel_then_spawn.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_cancel_then_spawn.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_cancellation_race.swift b/test/Concurrency/Runtime/async_taskgroup_cancellation_race.swift
new file mode 100644
index 0000000000000..96268d37c0914
--- /dev/null
+++ b/test/Concurrency/Runtime/async_taskgroup_cancellation_race.swift
@@ -0,0 +1,59 @@
+// RUN: %target-run-simple-swift
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: libdispatch
+// REQUIRES: concurrency_runtime
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: back_deploy_concurrency
+// UNSUPPORTED: freestanding
+
+func unorderedResults<R>(
+    _ fns: [@Sendable () async -> R]) -> (Task<(), Never>, AsyncStream<R>) {
+        var capturedContinuation: AsyncStream<R>.Continuation? = nil
+        let stream = AsyncStream<R> { continuation in
+            capturedContinuation = continuation
+        }
+
+        guard let capturedContinuation = capturedContinuation else {
+            fatalError("failed to capture continuation")
+        }
+
+        let task = Task.detached {
+            await withTaskGroup(of: Void.self) { group in
+                for fn in fns {
+                    group.addTask {
+                        let _ = capturedContinuation.yield(await fn())
+                    }
+                }
+                await group.waitForAll()
+            }
+            capturedContinuation.finish()
+        }
+
+        let result = (task, stream)
+
+        return result
+    }
+
+var fns: [@Sendable () async -> String] = [
+    {
+      try? await Task.sleep(nanoseconds: .random(in: 0..<50000))
+      return "hello"
+    }
+]
+
+fns.append(fns[0])
+fns.append(fns[0])
+
+// This is a race that will crash or trigger an assertion failure if there's an
+// issue. If we get to the end then we pass.
+for _ in 0..<1000 {
+  let (t, s) = unorderedResults(fns)
+
+  for try await x in s {
+    _ = x
+    if Bool.random() { t.cancel() }
+  }
+}
diff --git a/test/Concurrency/Runtime/async_taskgroup_discarding.swift b/test/Concurrency/Runtime/async_taskgroup_discarding.swift
index 7bb390ae0bcce..9684d834a7496 100644
--- a/test/Concurrency/Runtime/async_taskgroup_discarding.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_discarding.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // TODO: move to target-run-simple-leaks-swift once CI is using at least Xcode 14.3
 
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_discarding_dontLeak.swift b/test/Concurrency/Runtime/async_taskgroup_discarding_dontLeak.swift
index fe185503dbbbd..cdc4dc8a2bd40 100644
--- a/test/Concurrency/Runtime/async_taskgroup_discarding_dontLeak.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_discarding_dontLeak.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // TODO: move to target-run-simple-leaks-swift once CI is using at least Xcode 14.3
 
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_discarding_dontLeak_class_error.swift b/test/Concurrency/Runtime/async_taskgroup_discarding_dontLeak_class_error.swift
index 599ea8455f1c4..566ab948654d8 100644
--- a/test/Concurrency/Runtime/async_taskgroup_discarding_dontLeak_class_error.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_discarding_dontLeak_class_error.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/async_taskgroup_discarding_neverConsumingTasks.swift b/test/Concurrency/Runtime/async_taskgroup_discarding_neverConsumingTasks.swift
index cacde94631888..e3f850073327a 100644
--- a/test/Concurrency/Runtime/async_taskgroup_discarding_neverConsumingTasks.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_discarding_neverConsumingTasks.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: concurrency_runtime
@@ -85,9 +87,32 @@ func test_discardingTaskGroup_neverConsume(sleepBeforeGroupWaitAll: Duration) as
   print("all tasks: \(allTasks)")
 }
 
+func test_discardingTaskGroup_bigReturn() async {
+  print(">>> \(#function)")
+
+  // Test returning a very large value to ensure we don't overflow memory.
+  let array = await withDiscardingTaskGroup { group in
+    group.addTask {}
+    try? await Task.sleep(until: .now + .milliseconds(100), clock: .continuous)
+
+    // InlineArray.init(repeating:) uses a lot of stack space with optimizations
+    // disabled, so set one up in a less friendly but less stack-consuming way.
+    let ptr = UnsafeMutablePointer<InlineArray<32768, Int>>.allocate(capacity: 1)
+    ptr.withMemoryRebound(to: Int.self, capacity: 32768) {
+      $0.initialize(repeating: 12345, count: 32768)
+    }
+    // Deliberately leak `ptr` to avoid needing to save any temporaries.
+    return ptr.pointee
+  }
+
+  // CHECK: Huge return value produced: 12345 12345
+  print("Huge return value produced:", array[0], array[32767])
+}
+
 @main struct Main {
   static func main() async {
     await test_discardingTaskGroup_neverConsume()
     await test_discardingTaskGroup_neverConsume(sleepBeforeGroupWaitAll: .milliseconds(500))
+    await test_discardingTaskGroup_bigReturn()
   }
 }
diff --git a/test/Concurrency/Runtime/async_taskgroup_dontLeakTasks.swift b/test/Concurrency/Runtime/async_taskgroup_dontLeakTasks.swift
index 4ae3cf7bd8990..ef6cbfa3d00d1 100644
--- a/test/Concurrency/Runtime/async_taskgroup_dontLeakTasks.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_dontLeakTasks.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // TODO: move to target-run-simple-leaks-swift once CI is using at least Xcode 14.3
 
 // Task group addTask is not supported in freestanding mode
diff --git a/test/Concurrency/Runtime/async_taskgroup_is_asyncsequence.swift b/test/Concurrency/Runtime/async_taskgroup_is_asyncsequence.swift
index 5ad856a840f90..b5112153de790 100644
--- a/test/Concurrency/Runtime/async_taskgroup_is_asyncsequence.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_is_asyncsequence.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_is_empty.swift b/test/Concurrency/Runtime/async_taskgroup_is_empty.swift
index 63d426c55d546..4621e0b5db2c6 100644
--- a/test/Concurrency/Runtime/async_taskgroup_is_empty.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_is_empty.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_next_not_invoked_cancelAll.swift b/test/Concurrency/Runtime/async_taskgroup_next_not_invoked_cancelAll.swift
index a6323369c9fd7..99fafc55a45ed 100644
--- a/test/Concurrency/Runtime/async_taskgroup_next_not_invoked_cancelAll.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_next_not_invoked_cancelAll.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_next_not_invoked_without_cancelAll.swift b/test/Concurrency/Runtime/async_taskgroup_next_not_invoked_without_cancelAll.swift
index b6375965d06c3..22062f13b0a18 100644
--- a/test/Concurrency/Runtime/async_taskgroup_next_not_invoked_without_cancelAll.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_next_not_invoked_without_cancelAll.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_next_on_completed.swift b/test/Concurrency/Runtime/async_taskgroup_next_on_completed.swift
index fcf7206a0654a..f9df0697a7e97 100644
--- a/test/Concurrency/Runtime/async_taskgroup_next_on_completed.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_next_on_completed.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_next_on_pending.swift b/test/Concurrency/Runtime/async_taskgroup_next_on_pending.swift
index 65832ebcfec61..a79899e36bf34 100644
--- a/test/Concurrency/Runtime/async_taskgroup_next_on_pending.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_next_on_pending.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
@@ -8,6 +10,7 @@
 // UNSUPPORTED: OS=watchos
 
 // REQUIRES: concurrency_runtime
+// UNSUPPORTED: back_deployment_runtime
 
 import Dispatch
 
diff --git a/test/Concurrency/Runtime/async_taskgroup_throw_recover.swift b/test/Concurrency/Runtime/async_taskgroup_throw_recover.swift
index a6225ab24a4b9..8c0534c078c3a 100644
--- a/test/Concurrency/Runtime/async_taskgroup_throw_recover.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_throw_recover.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/async_taskgroup_throw_rethrow.swift b/test/Concurrency/Runtime/async_taskgroup_throw_rethrow.swift
index 82fad46a9b81d..76f0ca7c0f822 100644
--- a/test/Concurrency/Runtime/async_taskgroup_throw_rethrow.swift
+++ b/test/Concurrency/Runtime/async_taskgroup_throw_rethrow.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/basic_future.swift b/test/Concurrency/Runtime/basic_future.swift
index 71cef47fc60a1..a48939b8b2157 100644
--- a/test/Concurrency/Runtime/basic_future.swift
+++ b/test/Concurrency/Runtime/basic_future.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple  %import-libdispatch -parse-as-library)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple  %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/cancellation_handler.swift b/test/Concurrency/Runtime/cancellation_handler.swift
index f21ed50b754b7..aa4534758087f 100644
--- a/test/Concurrency/Runtime/cancellation_handler.swift
+++ b/test/Concurrency/Runtime/cancellation_handler.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // REQUIRES: concurrency
 // REQUIRES: executable_test
 
diff --git a/test/Concurrency/Runtime/cancellation_handler_concurrent.swift b/test/Concurrency/Runtime/cancellation_handler_concurrent.swift
new file mode 100644
index 0000000000000..3579459b2cc4a
--- /dev/null
+++ b/test/Concurrency/Runtime/cancellation_handler_concurrent.swift
@@ -0,0 +1,35 @@
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+// REQUIRES: concurrency
+// REQUIRES: executable_test
+
+// REQUIRES: concurrency_runtime
+// UNSUPPORTED: freestanding
+
+func recurseABunch(_ call: () async throws -> Void, n: Int = 100) async throws {
+  try await withTaskCancellationHandler {
+    if n == 0 {
+      try await call()
+      return
+    }
+
+    try await recurseABunch(call, n: n - 1)
+  } onCancel: {
+  }
+}
+
+for _ in 0..<100_000 {
+    let task: Task<Void, any Error> = Task {
+        try await Task.sleep(nanoseconds: UInt64.random(in: 0..<1_000))
+        try await recurseABunch() {
+          await withTaskCancellationHandler {
+          } onCancel: {
+          }
+        }
+    }
+    Task {
+        try await Task.sleep(nanoseconds: UInt64.random(in: 0..<1_000))
+        task.cancel()
+    }
+}
diff --git a/test/Concurrency/Runtime/cancellation_handler_only_once.swift b/test/Concurrency/Runtime/cancellation_handler_only_once.swift
index b188b1f0c02b0..d1f825b0d7dfb 100644
--- a/test/Concurrency/Runtime/cancellation_handler_only_once.swift
+++ b/test/Concurrency/Runtime/cancellation_handler_only_once.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -target %target-swift-5.1-abi-triple %import-libdispatch) | %FileCheck %s
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -target %target-swift-5.1-abi-triple %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // REQUIRES: concurrency
 // REQUIRES: executable_test
 
diff --git a/test/Concurrency/Runtime/checked_continuation.swift b/test/Concurrency/Runtime/checked_continuation.swift
index e2ef84d38bfd9..bdddfc15ee8d5 100644
--- a/test/Concurrency/Runtime/checked_continuation.swift
+++ b/test/Concurrency/Runtime/checked_continuation.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/clock.swift b/test/Concurrency/Runtime/clock.swift
index de418bf9874e6..8f876105bcd8e 100644
--- a/test/Concurrency/Runtime/clock.swift
+++ b/test/Concurrency/Runtime/clock.swift
@@ -1,5 +1,7 @@
 // RUN: %target-typecheck-verify-swift -strict-concurrency=complete -disable-availability-checking -parse-as-library
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library)
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
@@ -158,6 +160,13 @@ import StdlibUnittest
       }
     }
 
+    tests.test("Ensure abi layout size of Instant") {
+      // If this test fails it means the ABI of ContinuousClock.Instant has been broken!
+      // it MUST be the same laoyut of that of Duration
+      expectEqual(MemoryLayout<ContinuousClock.Instant>.size, MemoryLayout<Duration>.size)
+      expectEqual(MemoryLayout<SuspendingClock.Instant>.size, MemoryLayout<Duration>.size)
+    }
+
     await runAllTestsAsync()
   }
 }
diff --git a/test/Concurrency/Runtime/clocks.swift b/test/Concurrency/Runtime/clocks.swift
deleted file mode 100644
index 731cda3503d42..0000000000000
--- a/test/Concurrency/Runtime/clocks.swift
+++ /dev/null
@@ -1,276 +0,0 @@
-// RUN: %target-run-simple-swift(%import-libdispatch -parse-as-library)
-
-// REQUIRES: concurrency
-// REQUIRES: executable_test
-
-// rdar://106849189 move-only types should be supported in freestanding mode
-// UNSUPPORTED: freestanding
-
-// UNSUPPORTED: back_deployment_runtime
-// REQUIRES: concurrency_runtime
-
-import StdlibUnittest
-
-@available(SwiftStdlib 6.2, *)
-struct TickingClock: Clock {
-  struct Duration: DurationProtocol {
-    var ticks: Int
-
-    static func / (_ lhs: Self, _ rhs: Int) -> Self {
-      return Duration(ticks: lhs.ticks / rhs)
-    }
-    static func * (_ lhs: Self, rhs: Int) -> Self {
-      return Duration(ticks: lhs.ticks * rhs)
-    }
-    static func / (_ lhs: Self, _ rhs: Self) -> Double {
-      return Double(lhs.ticks) / Double(rhs.ticks)
-    }
-    static func < (_ lhs: Self, _ rhs: Self) -> Bool {
-      return lhs.ticks < rhs.ticks
-    }
-    static func + (_ lhs: Self, _ rhs: Self) -> Self {
-      return Duration(ticks: lhs.ticks + rhs.ticks)
-    }
-    static func - (_ lhs: Self, _ rhs: Self) -> Self {
-      return Duration(ticks: lhs.ticks - rhs.ticks)
-    }
-
-    static var zero: Self {
-      return Duration(ticks: 0)
-    }
-  }
-  struct Instant: InstantProtocol {
-    typealias Duration = TickingClock.Duration
-    var ticksFromStart: Int
-
-    func advanced(by duration: Duration) -> Self {
-      return Instant(ticksFromStart: self.ticksFromStart + duration.ticks)
-    }
-    func duration(to other: Self) -> Duration {
-      return Duration(ticks: other.ticksFromStart - self.ticksFromStart)
-    }
-
-    static func < (_ lhs: Self, _ rhs: Self) -> Bool {
-      return lhs.ticksFromStart < rhs.ticksFromStart
-    }
-  }
-
-  private var _now: Instant
-  var now: Instant { return _now }
-  var minimumResolution: Duration { return Duration(ticks: 1) }
-  var traits: ClockTraits { [.monotonic] }
-
-  init() {
-    _now = Instant(ticksFromStart: 0)
-  }
-
-  // These are a bit of a lie, since this clock is weird and doesn't
-  // actually tell the time; for the purposes of this test, we pretend
-  // that the ticks are 20ms.
-  func convert(from duration: Duration) -> Swift.Duration? {
-    return .seconds(Double(duration.ticks) / 50)
-  }
-
-  func convert(from duration: Swift.Duration) -> Duration? {
-    let (seconds, attoseconds) = duration.components
-    let extraTicks = attoseconds / 20_000_000_000_000_000
-    return Duration(ticks: Int(seconds * 50) + Int(extraTicks))
-  }
-
-  mutating func tick() {
-    _now.ticksFromStart += 1
-  }
-
-  func sleep(
-    until instant: Instant,
-    tolerance: Duration? = nil
-  ) async throws {
-    // Do nothing
-  }
-}
-
-@available(SwiftStdlib 6.2, *)
-struct TockingClock: Clock {
-  struct Duration: DurationProtocol {
-    var tocks: Int
-
-    static func / (_ lhs: Self, _ rhs: Int) -> Self {
-      return Duration(tocks: lhs.tocks / rhs)
-    }
-    static func * (_ lhs: Self, rhs: Int) -> Self {
-      return Duration(tocks: lhs.tocks * rhs)
-    }
-    static func / (_ lhs: Self, _ rhs: Self) -> Double {
-      return Double(lhs.tocks) / Double(rhs.tocks)
-    }
-    static func < (_ lhs: Self, _ rhs: Self) -> Bool {
-      return lhs.tocks < rhs.tocks
-    }
-    static func + (_ lhs: Self, _ rhs: Self) -> Self {
-      return Duration(tocks: lhs.tocks + rhs.tocks)
-    }
-    static func - (_ lhs: Self, _ rhs: Self) -> Self {
-      return Duration(tocks: lhs.tocks - rhs.tocks)
-    }
-
-    static var zero: Self {
-      return Duration(tocks: 0)
-    }
-  }
-  struct Instant: InstantProtocol {
-    typealias Duration = TockingClock.Duration
-    var tocksFromStart: Int
-
-    func advanced(by duration: Duration) -> Self {
-      return Instant(tocksFromStart: self.tocksFromStart + duration.tocks)
-    }
-    func duration(to other: Self) -> Duration {
-      return Duration(tocks: other.tocksFromStart - self.tocksFromStart)
-    }
-
-    static func < (_ lhs: Self, _ rhs: Self) -> Bool {
-      return lhs.tocksFromStart < rhs.tocksFromStart
-    }
-  }
-
-  private var _now: Instant
-  var now: Instant { return _now }
-  var minimumResolution: Duration { return Duration(tocks: 1) }
-  var traits: ClockTraits { [.monotonic] }
-
-  init() {
-    _now = Instant(tocksFromStart: 1000)
-  }
-
-  // These are a bit of a lie, since this clock is weird and doesn't
-  // actually tell the time; for the purposes of this test, we pretend
-  // that the tocks are 10ms.
-  func convert(from duration: Duration) -> Swift.Duration? {
-    return .seconds(Double(duration.tocks) / 100)
-  }
-
-  func convert(from duration: Swift.Duration) -> Duration? {
-    let (seconds, attoseconds) = duration.components
-    let extraTocks = attoseconds / 10_000_000_000_000_000
-    return Duration(tocks: Int(seconds * 100) + Int(extraTocks))
-  }
-
-  mutating func tock() {
-    _now.tocksFromStart += 1
-  }
-
-  func sleep(
-    until instant: Instant,
-    tolerance: Duration? = nil
-  ) async throws {
-    // Do nothing
-  }
-}
-
-@available(SwiftStdlib 6.2, *)
-@main struct Main {
-  static func main() {
-    let tests = TestSuite("clocks")
-
-    var clockA = TickingClock()
-    let clockB = TickingClock()
-
-    clockA.tick()
-    clockA.tick()
-    clockA.tick()
-
-    var clockC = TockingClock()
-
-    clockC.tock()
-
-    tests.test("Convert instants from one clock to another") {
-      let nowA = clockA.now
-      let nowB = clockB.now
-
-      expectEqual(nowA.ticksFromStart, 3)
-      expectEqual(nowB.ticksFromStart, 0)
-
-      let futureA = nowA.advanced(by: TickingClock.Duration(ticks: 23))
-      let futureB = nowB.advanced(by: TickingClock.Duration(ticks: 42))
-
-      expectEqual(futureA.ticksFromStart, 26)
-      expectEqual(futureB.ticksFromStart, 42)
-
-      let futureAinB = clockB.convert(instant: futureA, from: clockA)!
-      let futureBinA = clockA.convert(instant: futureB, from: clockB)!
-
-      expectEqual(futureAinB.ticksFromStart, 23)
-      expectEqual(futureBinA.ticksFromStart, 45)
-
-      let futureAinBinA = clockA.convert(instant: futureAinB, from: clockB)!
-      let futureBinAinB = clockB.convert(instant: futureBinA, from: clockA)!
-
-      expectEqual(futureAinBinA.ticksFromStart, futureA.ticksFromStart)
-      expectEqual(futureBinAinB.ticksFromStart, futureB.ticksFromStart)
-    }
-
-    tests.test("Convert instants between clocks with different representations") {
-      let nowA = clockA.now
-      let nowC = clockC.now
-
-      expectEqual(nowA.ticksFromStart, 3)
-      expectEqual(nowC.tocksFromStart, 1001)
-
-      let futureA = nowA.advanced(by: TickingClock.Duration(ticks: 23))
-      let futureC = nowC.advanced(by: TockingClock.Duration(tocks: 42))
-
-      expectEqual(futureA.ticksFromStart, 26)
-      expectEqual(futureC.tocksFromStart, 1043)
-
-      let futureAinC = clockC.convert(instant: futureA, from: clockA)!
-      let futureCinA = clockA.convert(instant: futureC, from: clockC)!
-
-      expectEqual(futureAinC.tocksFromStart, 1047)
-      expectEqual(futureCinA.ticksFromStart, 24)
-
-      let futureAinCinA = clockA.convert(instant: futureAinC, from: clockC)!
-      let futureCinAinC = clockC.convert(instant: futureCinA, from: clockA)!
-
-      expectEqual(futureAinCinA.ticksFromStart, futureA.ticksFromStart)
-      expectEqual(futureCinAinC.tocksFromStart, futureC.tocksFromStart)
-    }
-
-    tests.test("Convert instants between continuous and suspending clocks") {
-      let continuous = ContinuousClock()
-      let suspending = SuspendingClock()
-
-      let nowC = continuous.now
-      let nowS = suspending.now
-
-      let futureC = nowC.advanced(by: .seconds(5.3))
-      let futureS = nowS.advanced(by: .seconds(4.2))
-
-      let futureCinS = suspending.convert(instant: futureC,
-                                          from: .continuous)!
-      let futureSinC = continuous.convert(instant: futureS,
-                                          from: .suspending)!
-
-      let futureCinSinC = continuous.convert(instant: futureCinS,
-                                             from: .suspending)!
-      let futureSinCinS = suspending.convert(instant: futureSinC,
-                                             from: .continuous)!
-
-      // These clocks may not be exact, so allow differences of up to 50ms
-      var delta1 = futureCinSinC - futureC
-      var delta2 = futureSinCinS - futureS
-
-      // Duration is not SignedNumeric, so we have to do things this way
-      if delta1 < .zero {
-        delta1 = .zero - delta1
-      }
-      if delta2 < .zero {
-        delta2 = .zero - delta2
-      }
-
-      expectLT(delta1, .milliseconds(50))
-      expectLT(delta2, .milliseconds(50))
-    }
-
-    runAllTests()
-  }
-}
diff --git a/test/Concurrency/Runtime/continuation_validation.swift b/test/Concurrency/Runtime/continuation_validation.swift
index a956858f2d034..d7b315caab447 100644
--- a/test/Concurrency/Runtime/continuation_validation.swift
+++ b/test/Concurrency/Runtime/continuation_validation.swift
@@ -12,7 +12,7 @@
 // UNSUPPORTED: back_deploy_concurrency
 // UNSUPPORTED: use_os_stdlib
 // UNSUPPORTED: freestanding
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 import StdlibUnittest
 
diff --git a/test/Concurrency/Runtime/custom_executors.swift b/test/Concurrency/Runtime/custom_executors.swift
index 87bc68da3999e..6d3fe695cd54d 100644
--- a/test/Concurrency/Runtime/custom_executors.swift
+++ b/test/Concurrency/Runtime/custom_executors.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/custom_executors_complex_equality.swift b/test/Concurrency/Runtime/custom_executors_complex_equality.swift
index 78342138f7abf..b07ab1cab8fe1 100644
--- a/test/Concurrency/Runtime/custom_executors_complex_equality.swift
+++ b/test/Concurrency/Runtime/custom_executors_complex_equality.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -enable-experimental-move-only -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -Xfrontend -enable-experimental-move-only -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/custom_executors_complex_equality_crash.swift b/test/Concurrency/Runtime/custom_executors_complex_equality_crash.swift
index 4290618008890..62d7bbd95a3e0 100644
--- a/test/Concurrency/Runtime/custom_executors_complex_equality_crash.swift
+++ b/test/Concurrency/Runtime/custom_executors_complex_equality_crash.swift
@@ -3,11 +3,12 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %import-libdispatch %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %import-libdispatch %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %import-libdispatch %t/a.out
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %import-libdispatch %t/a.out
 
 // TODO: Need to find out how to combine %env- and %target-run and %import-libdispatch reliably.
 // UNSUPPORTED: OS=linux-gnu
+// UNSUPPORTED: OS=freebsd
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/custom_executors_complex_equality_subclass.swift b/test/Concurrency/Runtime/custom_executors_complex_equality_subclass.swift
index 1a4b8bb5218fc..a378c10af68db 100644
--- a/test/Concurrency/Runtime/custom_executors_complex_equality_subclass.swift
+++ b/test/Concurrency/Runtime/custom_executors_complex_equality_subclass.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -enable-experimental-move-only -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -Xfrontend -enable-experimental-move-only -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/custom_executors_default.swift b/test/Concurrency/Runtime/custom_executors_default.swift
index 1d4f9bb841aa4..4b41ce16fa549 100644
--- a/test/Concurrency/Runtime/custom_executors_default.swift
+++ b/test/Concurrency/Runtime/custom_executors_default.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/custom_executors_globalActor.swift b/test/Concurrency/Runtime/custom_executors_globalActor.swift
index 8342a70799c4e..5fde3591e6bef 100644
--- a/test/Concurrency/Runtime/custom_executors_globalActor.swift
+++ b/test/Concurrency/Runtime/custom_executors_globalActor.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( %import-libdispatch -strict-concurrency=complete -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( %import-libdispatch -strict-concurrency=complete -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/custom_executors_moveOnly_job.swift b/test/Concurrency/Runtime/custom_executors_moveOnly_job.swift
index 4f4423a27e6ca..5f892f7b45c56 100644
--- a/test/Concurrency/Runtime/custom_executors_moveOnly_job.swift
+++ b/test/Concurrency/Runtime/custom_executors_moveOnly_job.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/custom_executors_priority.swift b/test/Concurrency/Runtime/custom_executors_priority.swift
index 99f7fc21d0e03..aa5090f2aeb66 100644
--- a/test/Concurrency/Runtime/custom_executors_priority.swift
+++ b/test/Concurrency/Runtime/custom_executors_priority.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/custom_executors_protocol.swift b/test/Concurrency/Runtime/custom_executors_protocol.swift
index 0a4d23683110a..c9ebd2f10bbf7 100644
--- a/test/Concurrency/Runtime/custom_executors_protocol.swift
+++ b/test/Concurrency/Runtime/custom_executors_protocol.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -enable-experimental-move-only -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -Xfrontend -enable-experimental-move-only -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
diff --git a/test/Concurrency/Runtime/custom_main_executor.swift b/test/Concurrency/Runtime/custom_main_executor.swift
index bb5c0f5ef1b21..9af3300015b76 100644
--- a/test/Concurrency/Runtime/custom_main_executor.swift
+++ b/test/Concurrency/Runtime/custom_main_executor.swift
@@ -1,4 +1,11 @@
-// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -g %import-libdispatch -parse-as-library -executor-factory SimpleExecutorFactory) | %FileCheck %s
+// RUN: %target-run-simple-swift(-DTOPLEVEL_FACTORY -Xfrontend -disable-availability-checking -g %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift(-DPROTOCOL_FACTORY -Xfrontend -disable-availability-checking -g %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift(-DPROTOCOL_FACTORY_OVERRIDDEN -Xfrontend -disable-availability-checking -g %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift(-DPROTOCOL_FACTORY_DEFAULT -Xfrontend -disable-availability-checking -g %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift(-DPROTOCOL_FACTORY_DEFAULT2 -Xfrontend -disable-availability-checking -g %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -g %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -g %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
@@ -13,6 +20,10 @@
 import StdlibUnittest
 import Synchronization
 
+#if TOPLEVEL_FACTORY
+typealias DefaultExecutorFactory = SimpleExecutorFactory
+#endif
+
 struct SimpleExecutorFactory: ExecutorFactory {
   public static var mainExecutor: any MainExecutor {
     print("Creating main executor")
@@ -24,6 +35,15 @@ struct SimpleExecutorFactory: ExecutorFactory {
   }
 }
 
+struct FatalExecutorFactory: ExecutorFactory {
+  public static var mainExecutor: any MainExecutor {
+    fatalError("mainExecutor called on FatalExecutorFactory")
+  }
+  public static var defaultExecutor: any TaskExecutor {
+    fatalError("taskExecutor called on FatalExecutorFactory")
+  }
+}
+
 @available(SwiftStdlib 6.2, *)
 final class SimpleMainExecutor: MainExecutor, @unchecked Sendable {
   public var isRunning: Bool = false
@@ -68,12 +88,34 @@ final class SimpleTaskExecutor: TaskExecutor, @unchecked Sendable {
   }
 }
 
-func myAsyncFunction() async {
+@concurrent func myAsyncFunction() async {
   print("Hello World")
 }
 
+protocol AppProtocol {
+  #if PROTOCOL_FACTORY
+  associatedtype DefaultExecutorFactory
+  #endif
+  #if PROTOCOL_FACTORY_DEFAULT
+  associatedtype DefaultExecutorFactory = SimpleExecutorFactory
+  #endif
+  #if PROTOCOL_FACTORY_DEFAULT2 || PROTOCOL_FACTORY_OVERRIDDEN
+  associatedtype DefaultExecutorFactory = FatalExecutorFactory
+  #endif
+}
+
+#if PROTOCOL_FACTORY || PROTOCOL_FACTORY_DEFAULT2
+extension AppProtocol {
+  typealias DefaultExecutorFactory = SimpleExecutorFactory
+}
+#endif
+
 @available(SwiftStdlib 6.2, *)
-@main struct Main {
+@main struct Main: AppProtocol {
+  #if !TOPLEVEL_FACTORY && !PROTOCOL_FACTORY && !PROTOCOL_FACTORY_DEFAULT && !PROTOCOL_FACTORY_DEFAULT2
+  typealias DefaultExecutorFactory = SimpleExecutorFactory
+  #endif
+
   static func main() async {
     print("Hello")
     await myAsyncFunction()
diff --git a/test/Concurrency/Runtime/custom_task_executor_fast_path.swift b/test/Concurrency/Runtime/custom_task_executor_fast_path.swift
new file mode 100644
index 0000000000000..8e13b8f95e42b
--- /dev/null
+++ b/test/Concurrency/Runtime/custom_task_executor_fast_path.swift
@@ -0,0 +1,117 @@
+// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -g %import-libdispatch -parse-as-library) | %FileCheck %s
+
+// REQUIRES: concurrency
+// REQUIRES: executable_test
+
+// rdar://106849189 move-only types should be supported in freestanding mode
+// UNSUPPORTED: freestanding
+
+// UNSUPPORTED: back_deployment_runtime
+// REQUIRES: concurrency_runtime
+// REQUIRES: synchronization
+// REQUIRES: libdispatch
+
+import StdlibUnittest
+import Synchronization
+import Dispatch
+
+typealias DefaultExecutorFactory = SimpleExecutorFactory
+
+struct SimpleExecutorFactory: ExecutorFactory {
+  public static var mainExecutor: any MainExecutor {
+    return SimpleMainExecutor()
+  }
+  public static var defaultExecutor: any TaskExecutor {
+    return SimpleTaskExecutor()
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+final class SimpleMainExecutor: MainExecutor, @unchecked Sendable {
+  public var isRunning: Bool = false
+
+  var shouldStop: Bool = false
+  let queue = Mutex<[UnownedJob]>([])
+
+  func enqueue(_ job: consuming ExecutorJob) {
+    let unownedJob = UnownedJob(job)
+    queue.withLock {
+      $0.append(unownedJob)
+    }
+  }
+
+  func run() throws {
+    isRunning = true
+    while !shouldStop {
+      let jobs = queue.withLock {
+        let jobs = $0
+        $0.removeAll()
+        return jobs
+      }
+      for job in jobs {
+        job.runSynchronously(on: self.asUnownedSerialExecutor())
+      }
+    }
+    isRunning = false
+  }
+
+  func stop() {
+    shouldStop = true
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+final class SimpleTaskExecutor: TaskExecutor, @unchecked Sendable {
+  let queue = Mutex<[UnownedJob]>([])
+
+  func enqueue(_ job: consuming ExecutorJob) {
+    print("Enqueued")
+    let unownedJob = UnownedJob(job)
+    queue.withLock {
+      $0.append(unownedJob)
+    }
+  }
+
+  func run() throws {
+    while true {
+      let jobs = queue.withLock {
+        let jobs = $0
+        $0.removeAll()
+        return jobs
+      }
+      for job in jobs {
+        job.runSynchronously(on: self.asUnownedTaskExecutor())
+      }
+    }
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+@main struct Main {
+  static func main() async {
+    DispatchQueue.global().async {
+      try! (Task.defaultExecutor as! SimpleTaskExecutor).run()
+    }
+
+    await withTaskGroup { group in
+      for _ in 0..<3 {
+        group.addTask() {
+          for _ in 0..<100 {
+            await withUnsafeContinuation { cont in
+              cont.resume()
+            }
+          }
+        }
+      }
+    }
+
+  }
+}
+
+// If we're on the fast path, we'll only enqueue four times (once per group)
+
+// CHECK: Enqueued
+// CHECK: Enqueued
+// CHECK: Enqueued
+// CHECK: Enqueued
+// CHECK-NOT: Enqueued
diff --git a/test/Concurrency/Runtime/data_race_detection_legacy_warning.swift b/test/Concurrency/Runtime/data_race_detection_legacy_warning.swift
index 3c2c85fff9f65..7724b0f0602e6 100644
--- a/test/Concurrency/Runtime/data_race_detection_legacy_warning.swift
+++ b/test/Concurrency/Runtime/data_race_detection_legacy_warning.swift
@@ -6,7 +6,7 @@
 // will be able to have this behavior, however new apps will not. We use the
 // overrides to test the logic for legacy code remains functional.
 //
-// RUN: %env-SWIFT_UNEXPECTED_EXECUTOR_LOG_LEVEL=1 %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out 2>&1 | %FileCheck %s --dump-input=always
+// RUN: env %env-SWIFT_UNEXPECTED_EXECUTOR_LOG_LEVEL=1 %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out 2>&1 | %FileCheck %s --dump-input=always
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/effectful_properties.swift b/test/Concurrency/Runtime/effectful_properties.swift
index 1489261e26ce1..f00e1183cdc25 100644
--- a/test/Concurrency/Runtime/effectful_properties.swift
+++ b/test/Concurrency/Runtime/effectful_properties.swift
@@ -1,5 +1,12 @@
 // RUN: %target-run-simple-swift(-parse-as-library -target %target-swift-5.1-abi-triple) | %FileCheck %s
 
+// Enable this for nonisolated nonsending by default rdar://157226022 is
+// fixed. The test will fail otherwise since we hit an error due to inferring
+// nonisolated(nonsending) on the non-async property name.
+
+// XUN: %target-run-simple-swift(-parse-as-library -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault) | %FileCheck %s
+// XEQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // UNSUPPORTED: freestanding
diff --git a/test/Concurrency/Runtime/exclusivity.swift b/test/Concurrency/Runtime/exclusivity.swift
index 59792b315f8cd..f217e2db37253 100644
--- a/test/Concurrency/Runtime/exclusivity.swift
+++ b/test/Concurrency/Runtime/exclusivity.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library)
+// RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
@@ -6,7 +8,7 @@
 
 // REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 // UNSUPPORTED: back_deploy_concurrency
 
 // This test makes sure that:
@@ -365,7 +367,7 @@ struct Runner {
                 debugLog("==> Enter callee2")
                 debugLog("==> Exit callee2")
             }
-            
+
             // We add an inline never here to make sure that we do not eliminate
             // the dynamic access after inlining.
             @MainActor
@@ -374,7 +376,7 @@ struct Runner {
                 debugLog("==> Enter callee1")
                 let handle = Task { @MainActor in
                     debugLog("==> Enter callee1 Closure")
-                    
+
                     // These accesses end before we await in the task.
                     do {
                         callee2(&global1, &global2, &global3)
@@ -389,7 +391,7 @@ struct Runner {
                 await handle.value
                 debugLog("==> Exit callee1")
             }
-            
+
             debugLog("==> Enter 'testCase1'")
             await callee1()
             debugLog("==> Exit 'testCase1'")
diff --git a/test/Concurrency/Runtime/exclusivity_custom_executors.swift b/test/Concurrency/Runtime/exclusivity_custom_executors.swift
index 6a8fcc4aae6f3..09f40a10196d5 100644
--- a/test/Concurrency/Runtime/exclusivity_custom_executors.swift
+++ b/test/Concurrency/Runtime/exclusivity_custom_executors.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library)
+// RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
@@ -12,7 +14,7 @@
 // UNSUPPORTED: back_deploy_concurrency
 
 // Crash expectations can't be implemented on WASI/WebAssembly.
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 // This test makes sure that we properly save/restore access when we
 // synchronously launch a task from a serial executor. The access from the task
diff --git a/test/Concurrency/Runtime/executor_deinit1.swift b/test/Concurrency/Runtime/executor_deinit1.swift
index 73e56543429fa..862e7854f1c48 100644
--- a/test/Concurrency/Runtime/executor_deinit1.swift
+++ b/test/Concurrency/Runtime/executor_deinit1.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-parse-as-library  -target %target-swift-5.1-abi-triple %import-libdispatch) | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library  -target %target-swift-5.1-abi-triple %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/executor_deinit2.swift b/test/Concurrency/Runtime/executor_deinit2.swift
index a50bf58887f69..c444e0460d1d0 100644
--- a/test/Concurrency/Runtime/executor_deinit2.swift
+++ b/test/Concurrency/Runtime/executor_deinit2.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-parse-as-library  -target %target-swift-5.1-abi-triple) | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library  -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/executor_deinit3.swift b/test/Concurrency/Runtime/executor_deinit3.swift
index ef638cf957ff6..2e3ab21476057 100644
--- a/test/Concurrency/Runtime/executor_deinit3.swift
+++ b/test/Concurrency/Runtime/executor_deinit3.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-parse-as-library  -target %target-swift-5.1-abi-triple %import-libdispatch) | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library  -target %target-swift-5.1-abi-triple %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/future_fibonacci.swift b/test/Concurrency/Runtime/future_fibonacci.swift
index b62c5316090f6..75a85d3c0910b 100644
--- a/test/Concurrency/Runtime/future_fibonacci.swift
+++ b/test/Concurrency/Runtime/future_fibonacci.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple  %import-libdispatch -parse-as-library)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple  %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/isolated_conformance.swift b/test/Concurrency/Runtime/isolated_conformance.swift
index ca3a353440481..609bd3a8c2272 100644
--- a/test/Concurrency/Runtime/isolated_conformance.swift
+++ b/test/Concurrency/Runtime/isolated_conformance.swift
@@ -1,17 +1,12 @@
-// RUN: %target-run-simple-swift(-enable-experimental-feature IsolatedConformances -target %target-swift-5.1-abi-triple) | %FileCheck %s
+// RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple) | %FileCheck %s
+// RUN: %target-run-simple-swift(-target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: concurrency_runtime
-// REQUIRES: swift_feature_IsolatedConformances
 // UNSUPPORTED: back_deployment_runtime
 
-// FIXME: WebAssembly doesn't currently have a good way to install the
-// "isCurrentGlobalActor" hook on which this checking depends. Disable
-// the test for the moment.
-// UNSUPPORTED: wasm
-// UNSUPPORTED: CPU=wasm32
-
 protocol P {
   func f()
 }
@@ -209,6 +204,10 @@ await Task.detached { @SomeGlobalActor in
 print("Testing a separate task off the main actor")
 await Task.detached {
   if #available(SwiftStdlib 6.2, *) {
+    // Skip tests on platforms that use the same executor for the main
+    // actor and the global concurrent executor.
+    guard Task.defaultExecutor !== MainActor.executor else { return }
+
     precondition(!tryCastToP(mc))
     precondition(!tryCastToP(wrappedMC))
 
diff --git a/test/Concurrency/Runtime/isolated_macro_in_nonisolated_nonsending_func.swift b/test/Concurrency/Runtime/isolated_macro_in_nonisolated_nonsending_func.swift
new file mode 100644
index 0000000000000..06789bb3a2971
--- /dev/null
+++ b/test/Concurrency/Runtime/isolated_macro_in_nonisolated_nonsending_func.swift
@@ -0,0 +1,74 @@
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library) | %FileCheck %s --dump-input=always
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s --dump-input=always
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+// REQUIRES: concurrency
+// REQUIRES: executable_test
+// REQUIRES: concurrency_runtime
+
+// rdar://78109470
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: freestanding
+
+import _Concurrency
+import StdlibUnittest
+
+@main struct Main {
+  static func main() async {
+    await explicitIsolatedParam()
+    // CHECK: go - explicitIsolatedParam
+    // CHECK: outerIsolation = #isolation = Optional(Swift.MainActor)
+    // CHECK: Task{} #isolation = nil
+    // CHECK: Task{ [outerIsolation] } outerIsolation = Optional(Swift.MainActor), #iso = Optional(Swift.MainActor)
+    // CHECK: done - explicitIsolatedParam
+
+    print()
+    await nonisolatedNonsending()
+    // CHECK: go - nonisolatedNonsending
+    // CHECK: outerIsolation = #isolation = Optional(Swift.MainActor)
+    // CHECK: Task{} #isolation = nil
+    // CHECK: Task{ [outerIsolation] } outerIsolation = Optional(Swift.MainActor), #iso = nil
+    // CHECK: done - nonisolatedNonsending
+  }
+}
+
+func explicitIsolatedParam(isolation: isolated (any Actor)? = #isolation) async {
+  print("go - \(#function)")
+  MainActor.assertIsolated()
+
+  let outerIsolation = #isolation
+  print("outerIsolation = #isolation = \(String(describing: outerIsolation))")
+
+  await Task {
+    let iso = #isolation
+    print("Task{} #isolation = \(String(describing: iso))")
+  }.value
+
+  await Task {
+    let iso = #isolation
+    print("Task{ [outerIsolation] } outerIsolation = \(String(describing: isolation)), #iso = \(String(describing: iso))")
+  }.value
+
+  print("done - \(#function)")
+}
+
+
+nonisolated(nonsending) func nonisolatedNonsending() async {
+  print("go - \(#function)")
+  MainActor.assertIsolated()
+
+  let outerIsolation = #isolation
+  print("outerIsolation = #isolation = \(String(describing: outerIsolation))") // WRONG; this is nil today
+
+  await Task {
+    let iso = #isolation
+    print("Task{} #isolation = \(String(describing: iso))")
+  }.value
+
+  await Task {
+    let iso = #isolation
+    print("Task{ [outerIsolation] } outerIsolation = \(String(describing: outerIsolation)), #iso = \(String(describing: iso))")
+  }.value
+
+  print("done - \(#function)")
+}
diff --git a/test/Concurrency/Runtime/mainactor.swift b/test/Concurrency/Runtime/mainactor.swift
index f2be405fd3152..3a2ffe6f4936b 100644
--- a/test/Concurrency/Runtime/mainactor.swift
+++ b/test/Concurrency/Runtime/mainactor.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-parse-as-library -g -target %target-swift-5.1-abi-triple %import-libdispatch) | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library -g -target %target-swift-5.1-abi-triple %import-libdispatch -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/nonisolated_inherits_isolation.swift b/test/Concurrency/Runtime/nonisolated_inherits_isolation.swift
index e82c09d1cf49d..90bc2bcaa45ea 100644
--- a/test/Concurrency/Runtime/nonisolated_inherits_isolation.swift
+++ b/test/Concurrency/Runtime/nonisolated_inherits_isolation.swift
@@ -1,4 +1,6 @@
-// RUN: %target-run-simple-swift( -swift-version 6 -g %import-libdispatch -import-objc-header %S/Inputs/RunOnMainActor.h -enable-experimental-feature ExecutionAttribute -enable-experimental-feature AsyncCallerExecution )
+// RUN: %target-run-simple-swift( -swift-version 6 -g %import-libdispatch -import-objc-header %S/Inputs/RunOnMainActor.h -enable-upcoming-feature NonisolatedNonsendingByDefault )
+// RUN: %target-run-simple-swift( -swift-version 6 -g %import-libdispatch -import-objc-header %S/Inputs/RunOnMainActor.h -enable-upcoming-feature NonisolatedNonsendingByDefault  -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
@@ -6,8 +8,7 @@
 // REQUIRES: libdispatch
 // REQUIRES: asserts
 
-// REQUIRES: swift_feature_ExecutionAttribute
-// REQUIRES: swift_feature_AsyncCallerExecution
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // UNSUPPORTED: freestanding
 
@@ -34,13 +35,13 @@ struct CustomActor {
   }
 }
 
-@execution(caller)
+nonisolated(nonsending)
 func executionCallerIsolation() async {
   checkIfOnMainQueue()
 }
 
 // Expected to always crash
-@execution(concurrent)
+@concurrent
 func executionConcurrentIsolation() async {
   checkIfOnMainQueue()
 }
diff --git a/test/Concurrency/Runtime/reasync.swift b/test/Concurrency/Runtime/reasync.swift
index b6fea71ea21b5..d457fce61a578 100644
--- a/test/Concurrency/Runtime/reasync.swift
+++ b/test/Concurrency/Runtime/reasync.swift
@@ -7,6 +7,10 @@
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 
+// rdar://76038845
+// REQUIRES: concurrency_runtime
+// UNSUPPORTED: back_deployment_runtime
+
 import StdlibUnittest
 import reasync
 
diff --git a/test/Concurrency/Runtime/sleep_executor.swift b/test/Concurrency/Runtime/sleep_executor.swift
index f4767e5a068b3..d911a71eb931e 100644
--- a/test/Concurrency/Runtime/sleep_executor.swift
+++ b/test/Concurrency/Runtime/sleep_executor.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(%import-libdispatch -parse-as-library)
+// RUN: %target-run-simple-swift(%import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
@@ -21,8 +23,8 @@ actor MyActor {
 }
 
 @available(SwiftStdlib 6.2, *)
-final class TestExecutor: TaskExecutor, SchedulableExecutor, @unchecked Sendable {
-  var asSchedulable: SchedulableExecutor? {
+final class TestExecutor: TaskExecutor, SchedulingExecutor, @unchecked Sendable {
+  var asScheduling: SchedulingExecutor? {
     return self
   }
 
@@ -38,7 +40,7 @@ final class TestExecutor: TaskExecutor, SchedulableExecutor, @unchecked Sendable
                                 tolerance: C.Duration? = nil,
                                 clock: C) {
     // Convert to `Swift.Duration`
-    let duration = clock.convert(from: delay)!
+    let duration = delay as! Swift.Duration
 
     // Now turn that into nanoseconds
     let (seconds, attoseconds) = duration.components
diff --git a/test/Concurrency/Runtime/startImmediately.swift b/test/Concurrency/Runtime/startImmediately.swift
new file mode 100644
index 0000000000000..227a61970fc2b
--- /dev/null
+++ b/test/Concurrency/Runtime/startImmediately.swift
@@ -0,0 +1,562 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift -plugin-path %swift-plugin-dir -Xfrontend -disable-availability-checking %s %import-libdispatch -swift-version 6 -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s --dump-input=always
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: concurrency_runtime
+// REQUIRES: libdispatch
+
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: back_deploy_concurrency
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: freestanding
+
+import _Concurrency
+import Dispatch
+
+enum CompareHow {
+  case equal
+  case notEqual
+
+  func check(_ wasEqual: Bool) -> Bool {
+    switch self {
+    case .equal: wasEqual
+    case .notEqual: !wasEqual
+    }
+  }
+}
+
+#if canImport(Darwin)
+import Darwin
+typealias ThreadID = pthread_t
+func getCurrentThreadID() -> ThreadID { pthread_self() }
+func compareThreadIDs(_ a: ThreadID, _ how: CompareHow, _ b: ThreadID) -> Bool {
+  how.check(pthread_equal(a, b) != 0)
+}
+#elseif canImport(Glibc)
+import Glibc
+typealias ThreadID = pthread_t
+func getCurrentThreadID() -> ThreadID { pthread_self() }
+func compareThreadIDs(_ a: ThreadID, _ how: CompareHow, _ b: ThreadID) -> Bool {
+  how.check(pthread_equal(a, b) != 0)
+}
+#elseif os(Windows)
+import WinSDK
+typealias ThreadID = UInt32
+func getCurrentThreadID() -> ThreadID { GetCurrentThreadId() }
+func compareThreadIDs(_ a: ThreadID, _ how: CompareHow, _ b: ThreadID) -> Bool {
+  how.check(a == b)
+}
+#elseif os(WASI)
+typealias ThreadID = UInt32
+func getCurrentThreadID() -> ThreadID { 0 }
+func compareThreadIDs(_ a: ThreadID, _ how: CompareHow, _ b: ThreadID) -> Bool {
+  how.check(a == b)
+}
+#endif
+extension ThreadID: @unchecked Sendable {}
+
+@globalActor
+actor MyGlobalActor {
+  static let shared: MyGlobalActor = MyGlobalActor()
+
+  @MyGlobalActor
+  static func test() {}
+}
+
+final class NaiveQueueExecutor: SerialExecutor, TaskExecutor {
+  let queue: DispatchQueue
+
+  init(queue: DispatchQueue) {
+    self.queue = queue
+  }
+
+  public func enqueue(_ job: consuming ExecutorJob) {
+    let unowned = UnownedJob(job)
+    print("NaiveQueueExecutor(\(self.queue.label)) enqueue [thread:\(getCurrentThreadID())]")
+    queue.async {
+      unowned.runSynchronously(on: self.asUnownedSerialExecutor())
+    }
+  }
+}
+
+@globalActor
+actor DifferentGlobalActor {
+  static let queue = DispatchQueue(label: "DifferentGlobalActor-queue")
+  let executor: NaiveQueueExecutor
+  nonisolated let unownedExecutor: UnownedSerialExecutor
+
+  init() {
+    self.executor = NaiveQueueExecutor(queue: DifferentGlobalActor.queue)
+    self.unownedExecutor = executor.asUnownedSerialExecutor()
+  }
+
+  static let shared: DifferentGlobalActor = DifferentGlobalActor()
+
+  @DifferentGlobalActor
+  static func test() {}
+}
+
+// Test on all platforms
+func syncOnMyGlobalActor() -> [Task<Void, Never>] {
+  MyGlobalActor.shared.preconditionIsolated("Should be executing on the global actor here")
+  print("Confirmed to be on @MyGlobalActor")
+
+  // This task must be guaranteed to happen AFTER 'tt' because we are already on this actor
+  // so this enqueue must happen after we give up the actor.
+  print("schedule Task { @MyGlobalActor }, before immediate [thread:\(getCurrentThreadID())] @ :\(#line)")
+  let t1 = Task { @MyGlobalActor in
+    print("inside Task { @MyGlobalActor }, after sleep [thread:\(getCurrentThreadID())] @ :\(#line)")
+  }
+
+  print("before immediate [thread:\(getCurrentThreadID())] @ :\(#line)")
+  let outerTID = getCurrentThreadID()
+  let tt = Task.immediate { @MyGlobalActor in
+    let innerTID = getCurrentThreadID()
+    print("inside immediate, outer thread = \(outerTID)")
+    print("inside immediate, inner thread = \(innerTID)")
+    if (compareThreadIDs(outerTID, .notEqual, innerTID)) {
+      print("ERROR! Outer Thread ID must be equal Thread ID inside runSynchronously synchronous part!")
+    }
+
+    print("inside immediate, sleep now [thread:\(getCurrentThreadID())] @ :\(#line)")
+    _ = try? await Task.sleep(for: .seconds(1))
+    print("after sleep, inside immediate [thread:\(getCurrentThreadID())] @ :\(#line)")
+  }
+
+  return [t1, tt]
+}
+
+func syncOnMyGlobalActorHopToDifferentActor() -> [Task<Void, Never>] {
+  MyGlobalActor.shared.preconditionIsolated("Should be executing on the global actor here")
+  print("Confirmed to be on @MyGlobalActor")
+
+  // This task must be guaranteed to happen AFTER 'tt' because we are already on this actor
+  // so this enqueue must happen after we give up the actor.
+  print("schedule Task { @DifferentGlobalActor }, before immediate [thread:\(getCurrentThreadID())] @ :\(#line)")
+  let t1 = Task { @DifferentGlobalActor in
+    print("inside Task { @DifferentGlobalActor } [thread:\(getCurrentThreadID())] @ :\(#line)")
+    DifferentGlobalActor.shared.preconditionIsolated("Expected Task{} to be on DifferentGlobalActor")
+  }
+
+  print("before immediate [thread:\(getCurrentThreadID())] @ :\(#line)")
+  let outerTID = getCurrentThreadID()
+  let tt = Task.immediate { @DifferentGlobalActor in
+    let innerTID = getCurrentThreadID()
+    print("inside immediate, outer thread = \(outerTID)")
+    print("inside immediate, inner thread = \(innerTID)")
+    if (compareThreadIDs(outerTID, .equal, innerTID)) {
+      // This case specifically is NOT synchronously run because we specified a different isolation for the closure
+      // and FORCED a hop to the DifferentGlobalActor executor.
+      print("ERROR! Outer Thread ID must NOT equal Thread ID inside runSynchronously synchronous part!")
+    }
+    // We crucially need to see this task be enqueued on the different global actor,
+    // so it did not execute "synchronously" after all - it had to hop to the other actor.
+    dispatchPrecondition(condition: .onQueue(DifferentGlobalActor.queue))
+    DifferentGlobalActor.shared.preconditionIsolated("Expected Task.immediate { @DifferentGlobalActor in } to be on DifferentGlobalActor")
+
+    print("inside immediate, sleep now [thread:\(getCurrentThreadID())] @ :\(#line)")
+    _ = try? await Task.sleep(for: .milliseconds(100))
+
+    print("inside immediate, after sleep [thread:\(getCurrentThreadID())] @ :\(#line)")
+    dispatchPrecondition(condition: .onQueue(DifferentGlobalActor.queue))
+    DifferentGlobalActor.shared.preconditionIsolated("Expected Task.immediate { @DifferentGlobalActor in } to be on DifferentGlobalActor")
+
+    // do something here
+    await MyGlobalActor.test()
+    DifferentGlobalActor.test()
+  }
+
+  return [t1, tt]
+}
+
+func syncOnNonTaskThread(synchronousTask behavior: SynchronousTaskBehavior) {
+  let sem1 = DispatchSemaphore(value: 0)
+  let sem2 = DispatchSemaphore(value: 0)
+  let queue = DispatchQueue(label: "CustomQueue")
+
+  queue.async {
+    // This is in order so we don't have a "current task" nor any "current executor"
+    print("before immediate [thread:\(getCurrentThreadID())] @ :\(#line)")
+
+    let outerTID = getCurrentThreadID()
+    let tt = Task.immediate {
+      dispatchPrecondition(condition: .onQueue(queue))
+
+      let innerTID = getCurrentThreadID()
+      if compareThreadIDs(outerTID, .notEqual, innerTID) {
+        print("inside immediate, outer thread = \(outerTID)")
+        print("inside immediate, inner thread = \(innerTID)")
+        print("ERROR! Outer Thread ID must be equal Thread ID inside runSynchronously synchronous part!")
+      }
+      print("inside immediate [thread:\(getCurrentThreadID())] @ :\(#line)")
+
+      switch behavior {
+      case .suspend:
+        // sleep until woken up by outer task; i.e. actually suspend
+        print("inside immediate, before sleep [thread:\(getCurrentThreadID())] @ :\(#line)")
+        _ = try? await Task.sleep(for: .seconds(10))
+        print("inside immediate, after sleep [thread:\(getCurrentThreadID())] @ :\(#line)")
+      case .dontSuspend:
+        print("inside immediate, done [thread:\(getCurrentThreadID())] @ :\(#line)")
+        ()
+      }
+      sem1.signal()
+    }
+    print("after immediate, outside; cancel (wakeup) the synchronous task! [thread:\(getCurrentThreadID())] @ :\(#line)")
+    tt.cancel() // wake up the sleep
+
+    sem1.wait()
+    sem2.signal()
+  }
+
+  sem2.wait()
+}
+
+enum SynchronousTaskBehavior {
+  case suspend
+  case dontSuspend
+}
+
+print("\n\n==== ------------------------------------------------------------------")
+print("syncOnMyGlobalActor()")
+
+await Task { @MyGlobalActor in
+  MyGlobalActor.shared.preconditionIsolated("Should be executing on the global actor here")
+  for t in syncOnMyGlobalActor() {
+    await t.value
+  }
+}.value
+
+// CHECK-LABEL: syncOnMyGlobalActor()
+// CHECK: Confirmed to be on @MyGlobalActor
+// CHECK: schedule Task { @MyGlobalActor }, before immediate [thread:[[CALLING_THREAD:.*]]]
+// CHECK: before immediate [thread:[[CALLING_THREAD]]]
+// CHECK-NOT: ERROR!
+// CHECK: inside immediate, sleep now
+// CHECK: inside Task { @MyGlobalActor }, after sleep
+// resume on some other thread
+// CHECK: after sleep, inside immediate
+
+print("\n\n==== ------------------------------------------------------------------")
+print("syncOnMyGlobalActorHopToDifferentActor()")
+
+await Task { @MyGlobalActor in
+  MyGlobalActor.shared.preconditionIsolated("Should be executing on the global actor here")
+  for t in syncOnMyGlobalActorHopToDifferentActor() {
+    await t.value
+  }
+}.value
+
+// Assertion Notes: We expect the task to be on the specified queue as we force the Task.immediate
+// task to enqueue on the DifferentGlobalActor, however we CANNOT use threads to verify this behavior,
+// because dispatch may still pull tricks and reuse threads. We can only verify that we're on the right
+// queue, and that the `enqueue` calls on the target executor happen when we expect them to.
+//
+// CHECK: syncOnMyGlobalActorHopToDifferentActor()
+// CHECK: Confirmed to be on @MyGlobalActor
+// CHECK: before immediate
+
+// This IS actually enqueueing on the target actor (not synchronous), as expected:
+// CHECK: NaiveQueueExecutor(DifferentGlobalActor-queue) enqueue
+// CHECK: inside immediate, sleep now
+
+// After the sleep we get back onto the specified executor as expected
+// CHECK: NaiveQueueExecutor(DifferentGlobalActor-queue) enqueue
+// CHECK: inside immediate, after sleep
+
+print("\n\n==== ------------------------------------------------------------------")
+var behavior: SynchronousTaskBehavior = .suspend
+print("syncOnNonTaskThread(synchronousTask: \(behavior))")
+syncOnNonTaskThread(synchronousTask: behavior)
+
+// CHECK-LABEL: syncOnNonTaskThread(synchronousTask: suspend)
+// No interleaving allowed between "before" and "inside":
+// CHECK-NEXT: before immediate [thread:[[CALLING_THREAD2:.*]]]
+// CHECK-NOT: ERROR!
+// CHECK-NEXT: inside immediate [thread:[[CALLING_THREAD2]]]
+// CHECK-NEXT: inside immediate, before sleep [thread:[[CALLING_THREAD2]]]
+// CHECK-NEXT: after immediate, outside; cancel (wakeup) the synchronous task!  [thread:[[CALLING_THREAD2]]]
+// CHECK-NEXT: inside immediate, after sleep
+
+print("\n\n==== ------------------------------------------------------------------")
+behavior = .dontSuspend
+print("syncOnNonTaskThread(synchronousTask: \(behavior))")
+syncOnNonTaskThread(synchronousTask: behavior)
+
+// CHECK-LABEL: syncOnNonTaskThread(synchronousTask: dontSuspend)
+// CHECK-NEXT: before immediate [thread:[[CALLING_THREAD3:.*]]]
+// CHECK-NOT: ERROR!
+// CHECK-NEXT: inside immediate [thread:[[CALLING_THREAD3]]]
+// CHECK: inside immediate, done [thread:[[CALLING_THREAD3]]]
+// CHECK: after immediate, outside; cancel (wakeup) the synchronous task!  [thread:[[CALLING_THREAD3]]]
+
+print("\n\n==== ------------------------------------------------------------------")
+print("callActorFromStartSynchronousTask() - not on specific queue")
+callActorFromStartSynchronousTask(recipient: .recipient(Recipient()))
+
+// CHECK: callActorFromStartSynchronousTask()
+// No interleaving allowed between "before" and "inside":
+// CHECK: before immediate [thread:[[CALLING_THREAD4:.*]]]
+// CHECK-NEXT: inside immediate [thread:[[CALLING_THREAD4]]]
+
+// It is important that as we suspend on the actor call, the 'after' immediate gets to run
+// CHECK-NEXT: inside immediate, call rec.sync() [thread:[[CALLING_THREAD4]]]
+// CHECK: after immediate
+// CHECK-NOT: ERROR!
+// CHECK: inside immediate, call rec.sync() done
+
+// CHECK-NOT: ERROR!
+// CHECK: inside immediate, done
+
+/// Don't want to involve protocol calls to not confuse the test with additional details,
+/// so we use concrete types here.
+enum TargetActorToCall {
+  case recipient(Recipient)
+  case recipientOnQueue(RecipientOnQueue)
+}
+
+protocol RecipientProtocol where Self: Actor {
+  func callAndSuspend(syncTaskThreadID: ThreadID) async
+}
+
+// default actor, must not declare an 'unownedExecutor'
+actor Recipient: RecipientProtocol {
+  func callAndSuspend(syncTaskThreadID: ThreadID) async {
+    self.preconditionIsolated()
+
+    print("\(Recipient.self)/\(#function) Current actor thread id = \(getCurrentThreadID()) @ :\(#line)")
+    if compareThreadIDs(syncTaskThreadID, .equal, getCurrentThreadID()) {
+      print("NOTICE: Actor must not run on the synchronous task's thread :\(#line)")
+    }
+
+    try? await Task.sleep(for: .milliseconds(100))
+  }
+}
+
+func callActorFromStartSynchronousTask(recipient rec: TargetActorToCall) {
+  let sem1 = DispatchSemaphore(value: 0)
+  let sem2 = DispatchSemaphore(value: 0)
+  let queue = DispatchQueue(label: "CustomQueue")
+
+  queue.async {
+    let outerTID = getCurrentThreadID()
+    print("before immediate [thread:\(outerTID)] @ :\(#line)")
+    let tt = Task.immediate {
+      dispatchPrecondition(condition: .onQueue(queue))
+
+      let innerTID = getCurrentThreadID()
+      precondition(compareThreadIDs(outerTID, .equal, innerTID), "Outer Thread ID must be equal Thread ID inside runSynchronously synchronous part!")
+      print("inside immediate [thread:\(getCurrentThreadID())] @ :\(#line)")
+
+      for i in 1..<10 {
+        queue.async {
+          print("- async work on queue")
+        }
+      }
+
+      print("inside immediate, call rec.sync() [thread:\(getCurrentThreadID())] @ :\(#line)")
+      switch rec {
+      case .recipient(let recipient): await recipient.callAndSuspend(syncTaskThreadID: innerTID)
+      case .recipientOnQueue(let recipient): await recipient.callAndSuspend(syncTaskThreadID: innerTID)
+      }
+      print("inside immediate, call rec.sync() done [thread:\(getCurrentThreadID())] @ :\(#line)")
+
+      // after suspension we are supposed to hop off to the global pool,
+      // thus the thread IDs cannot be the same anymore
+      print("Inner thread id = \(innerTID)")
+      print("Current thread id = \(getCurrentThreadID())")
+      // Dispatch may end up reusing the thread used to service the queue so we
+      // cannot truly assert exact thread identity in such tests.
+      // Usually this will be on a different thread by now though.
+      if compareThreadIDs(innerTID, .equal, getCurrentThreadID()) {
+        print("NOTICE: Task resumed on same thread as it entered the synchronous task!")
+      }
+
+      print("inside immediate, done [thread:\(getCurrentThreadID())] @ :\(#line)")
+      sem1.signal()
+    }
+
+    print("after immediate [thread:\(getCurrentThreadID())] @ :\(#line)")
+    sem2.signal()
+  }
+
+  sem1.wait()
+  sem2.wait()
+}
+
+print("\n\n==== ------------------------------------------------------------------")
+print("callActorFromStartSynchronousTask() - actor in custom executor with its own queue")
+let actorQueue = DispatchQueue(label: "recipient-actor-queue")
+callActorFromStartSynchronousTask(recipient: .recipientOnQueue(RecipientOnQueue(queue: actorQueue)))
+
+// CHECK-LABEL: callActorFromStartSynchronousTask() - actor in custom executor with its own queue
+// No interleaving allowed between "before" and "inside":
+// CHECK: before immediate [thread:[[CALLING_THREAD4:.*]]]
+// CHECK-NEXT: inside immediate [thread:[[CALLING_THREAD4]]]
+
+// As we call into an actor, we must enqueue to its custom executor;
+// Make sure the enqueue happens as expected and only then do we give up the calling thread
+// allowing the 'after immediate' to run.
+//
+// CHECK-NEXT: inside immediate, call rec.sync() [thread:[[CALLING_THREAD4]]]
+// CHECK: after immediate
+// CHECK-NOT: ERROR!
+// CHECK: inside immediate, call rec.sync() done
+
+// CHECK-NOT: ERROR!
+// CHECK: inside immediate, done
+
+actor RecipientOnQueue: RecipientProtocol {
+  let executor: NaiveQueueExecutor
+  nonisolated let unownedExecutor: UnownedSerialExecutor
+
+  init(queue: DispatchQueue) {
+    self.executor = NaiveQueueExecutor(queue: queue)
+    self.unownedExecutor = executor.asUnownedSerialExecutor()
+  }
+
+  func callAndSuspend(syncTaskThreadID: ThreadID) async {
+    self.preconditionIsolated()
+    dispatchPrecondition(condition: .onQueue(self.executor.queue))
+
+    print("\(Recipient.self)/\(#function) Current actor thread id = \(getCurrentThreadID()) @ :\(#line)")
+    if compareThreadIDs(syncTaskThreadID, .equal, getCurrentThreadID()) {
+      print("NOTICE: Actor must not run on the synchronous task's thread :\(#line)")
+    }
+
+    try? await Task.sleep(for: .milliseconds(100))
+  }
+}
+
+print("\n\n==== ------------------------------------------------------------------")
+print("call_taskImmediate_insideActor()")
+
+actor A {
+  func f() {
+    Task.immediate(name: "hello") { print("Task.immediate (\(Task.name!))") }
+    Task.immediate() { print("Task.immediate") }
+
+    Task.immediate(name: "hello") { @MainActor in print("Task.immediate { @MainActor } (\(Task.name!))") }
+    Task.immediate() { @MainActor in print("Task.immediate { @MainActor }") }
+  }
+}
+
+func call_immediate_insideActor() async {
+  await A().f()
+}
+await call_immediate_insideActor()
+
+
+print("\n\n==== ------------------------------------------------------------------")
+print("call_taskImmediate_taskExecutor()")
+
+@TaskLocal
+nonisolated(unsafe) var niceTaskLocalValueYouGotThere: String = ""
+
+// FIXME: rdar://155596073 Task executors execution may not always hop as expected
+func call_taskImmediate_taskExecutor(taskExecutor: NaiveQueueExecutor) async {
+  await Task.immediate(executorPreference: taskExecutor) {
+    print("Task.immediate(executorPreference:)")
+    dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue))
+    await Task.yield()
+    dispatchPrecondition(condition: .onQueue(taskExecutor.queue))
+  }.value
+
+  await Task.immediate(executorPreference: taskExecutor) { @MainActor in
+    print("Task.immediate(executorPreference:) { @MainActor }")
+    dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // since @MainActor requirement > preference
+    await Task.yield()
+    dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // since @MainActor requirement > preference
+  }.value
+
+  await $niceTaskLocalValueYouGotThere.withValue("value") {
+    assert(niceTaskLocalValueYouGotThere == "value")
+
+    // Task.immediate copies task locals
+    await Task.immediate(executorPreference: taskExecutor) {
+      assert(niceTaskLocalValueYouGotThere == "value")
+    }.value
+
+    // Task.immediateDetached does not copy task locals
+    await Task.immediateDetached(executorPreference: taskExecutor) {
+      assert(niceTaskLocalValueYouGotThere == "")
+    }.value
+  }
+
+  await withTaskGroup { group in
+    print("withTaskGroup { group.addTask(executorPreference:) { ... } }")
+    group.addImmediateTask(executorPreference: taskExecutor) {
+      print("addImmediateTask")
+      dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // "immediately" on caller
+      await Task.yield()
+      dispatchPrecondition(condition: .onQueue(taskExecutor.queue)) // hopped to preferred executor
+    }
+
+    let _: Bool = group.addImmediateTaskUnlessCancelled(executorPreference: taskExecutor) {
+      print("addImmediateTaskUnlessCancelled")
+      dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // "immediately" on caller
+      await Task.yield()
+      dispatchPrecondition(condition: .onQueue(taskExecutor.queue)) // hopped to preferred executor
+    }
+  }
+
+  await withThrowingTaskGroup { group in
+    print("withThrowingTaskGroup { group.addTask(executorPreference:) { ... } }")
+    group.addImmediateTask(executorPreference: taskExecutor) {
+      print("addImmediateTask")
+      dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // "immediately" on caller
+      await Task.yield()
+      dispatchPrecondition(condition: .onQueue(taskExecutor.queue)) // hopped to preferred executor
+    }
+
+    let _: Bool = group.addImmediateTaskUnlessCancelled(executorPreference: taskExecutor) {
+      print("addImmediateTaskUnlessCancelled")
+      dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // "immediately" on caller
+      await Task.yield()
+      dispatchPrecondition(condition: .onQueue(taskExecutor.queue)) // hopped to preferred executor
+    }
+  }
+
+  await withDiscardingTaskGroup { group in
+    print("withDiscardingTaskGroup { group.addTask(executorPreference:) { ... } }")
+    group.addImmediateTask(executorPreference: taskExecutor) {
+      print("addImmediateTask")
+      dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // "immediately" on caller
+      await Task.yield()
+      dispatchPrecondition(condition: .onQueue(taskExecutor.queue)) // hopped to preferred executor
+    }
+
+    let _: Bool = group.addImmediateTaskUnlessCancelled(executorPreference: taskExecutor) {
+      print("addImmediateTaskUnlessCancelled")
+      dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // "immediately" on caller
+      await Task.yield()
+      dispatchPrecondition(condition: .onQueue(taskExecutor.queue)) // hopped to preferred executor
+    }
+  }
+
+  await withDiscardingTaskGroup { group in
+    print("withDiscardingTaskGroup { group.addTask(executorPreference:) { ... } }")
+    group.addImmediateTask(executorPreference: taskExecutor) {
+      print("addImmediateTask")
+      dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // "immediately" on caller
+      await Task.yield()
+      dispatchPrecondition(condition: .onQueue(taskExecutor.queue)) // hopped to preferred executor
+    }
+
+    let _: Bool = group.addImmediateTaskUnlessCancelled(executorPreference: taskExecutor) {
+      print("addImmediateTaskUnlessCancelled")
+      dispatchPrecondition(condition: .notOnQueue(taskExecutor.queue)) // "immediately" on caller
+      await Task.yield()
+      dispatchPrecondition(condition: .onQueue(taskExecutor.queue)) // hopped to preferred executor
+    }
+  }
+}
+
+// FIXME: rdar://155596073 task executors can be somewhat racy it seems and not always hop as we'd want them to
+// await call_taskImmediate_taskExecutor(
+//  taskExecutor: NaiveQueueExecutor(queue: DispatchQueue(label: "my-queue")))
+
+print("DONE!") // CHECK: DONE!
diff --git a/test/Concurrency/Runtime/startImmediately_order.swift b/test/Concurrency/Runtime/startImmediately_order.swift
new file mode 100644
index 0000000000000..7dbd579e37afa
--- /dev/null
+++ b/test/Concurrency/Runtime/startImmediately_order.swift
@@ -0,0 +1,64 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift -Xfrontend -disable-availability-checking %s %import-libdispatch -swift-version 6 -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: concurrency_runtime
+
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: back_deploy_concurrency
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: freestanding
+
+import _Concurrency
+
+let max = 1000
+
+func bar(x: Int, cc: CheckedContinuation<Void, Never>) {
+  Task.immediate {
+    print("Task \(x) started")
+    try! await Task.sleep(nanoseconds: 10000)
+    if (x == max) {
+      cc.resume()
+    }
+  }
+}
+
+await withCheckedContinuation { (cc: CheckedContinuation<Void, Never>) in
+  for i in 1...max {
+    bar(x: i, cc: cc)
+  }
+}
+
+// CHECK: Task 1 started
+// CHECK: Task 2 started
+// CHECK: Task 3 started
+// CHECK: Task 4 started
+// CHECK: Task 5 started
+// CHECK: Task 6 started
+// CHECK: Task 7 started
+// CHECK: Task 8 started
+// CHECK: Task 9 started
+// CHECK: Task 10 started
+// CHECK: Task 11 started
+// CHECK: Task 12 started
+// CHECK: Task 13 started
+// CHECK: Task 14 started
+// CHECK: Task 15 started
+// CHECK: Task 16 started
+// CHECK: Task 17 started
+// CHECK: Task 18 started
+// CHECK: Task 19 started
+// CHECK: Task 20 started
+// CHECK: Task 21 started
+// CHECK: Task 22 started
+// CHECK: Task 23 started
+// CHECK: Task 24 started
+// CHECK: Task 25 started
+// CHECK: Task 26 started
+// CHECK: Task 27 started
+// CHECK: Task 28 started
+// CHECK: Task 29 started
+// CHECK: Task 30 started
diff --git a/test/Concurrency/Runtime/startSynchronously.swift b/test/Concurrency/Runtime/startSynchronously.swift
deleted file mode 100644
index 27ebea1557b45..0000000000000
--- a/test/Concurrency/Runtime/startSynchronously.swift
+++ /dev/null
@@ -1,402 +0,0 @@
-// REQUIRES: rdar145735542
-// RUN: %empty-directory(%t)
-// RUN: %target-build-swift -Xfrontend -disable-availability-checking %s %import-libdispatch -swift-version 6 -o %t/a.out
-// RUN: %target-codesign %t/a.out
-// RUN: %target-run %t/a.out | %FileCheck %s --dump-input=always
-
-// REQUIRES: executable_test
-// REQUIRES: concurrency
-// REQUIRES: concurrency_runtime
-// REQUIRES: libdispatch
-
-// UNSUPPORTED: back_deployment_runtime
-// UNSUPPORTED: back_deploy_concurrency
-// UNSUPPORTED: use_os_stdlib
-// UNSUPPORTED: freestanding
-
-import _Concurrency
-import Dispatch
-
-enum CompareHow {
-  case equal
-  case notEqual
-
-  func check(_ wasEqual: Bool) -> Bool {
-    switch self {
-    case .equal: wasEqual
-    case .notEqual: !wasEqual
-    }
-  }
-}
-
-#if canImport(Darwin)
-import Darwin
-typealias ThreadID = pthread_t
-func getCurrentThreadID() -> ThreadID { pthread_self() }
-func compareThreadIDs(_ a: ThreadID, _ how: CompareHow, _ b: ThreadID) -> Bool {
-  how.check(pthread_equal(a, b) != 0)
-}
-#elseif canImport(Glibc)
-import Glibc
-typealias ThreadID = pthread_t
-func getCurrentThreadID() -> ThreadID { pthread_self() }
-func compareThreadIDs(_ a: ThreadID, _ how: CompareHow, _ b: ThreadID) -> Bool {
-  how.check(pthread_equal(a, b) != 0)
-}
-#elseif os(Windows)
-import WinSDK
-typealias ThreadID = UInt32
-func getCurrentThreadID() -> ThreadID { GetCurrentThreadId() }
-func compareThreadIDs(_ a: ThreadID, _ how: CompareHow, _ b: ThreadID) -> Bool {
-  how.check(a == b)
-}
-#elseif os(WASI)
-typealias ThreadID = UInt32
-func getCurrentThreadID() -> ThreadID { 0 }
-func compareThreadIDs(_ a: ThreadID, _ how: CompareHow, _ b: ThreadID) -> Bool {
-  how.check(a == b)
-}
-#endif
-extension ThreadID: @unchecked Sendable {}
-
-@globalActor
-actor MyGlobalActor {
-  static let shared: MyGlobalActor = MyGlobalActor()
-}
-
-// Test on all platforms
-func syncOnMyGlobalActor() -> [Task<Void, Never>] {
-  MyGlobalActor.shared.preconditionIsolated("Should be executing on the global actor here")
-  print("Confirmed to be on @MyGlobalActor")
-
-  // This task must be guaranteed to happen AFTER 'tt' because we are already on this actor
-  // so this enqueue must happen after we give up the actor.
-  print("schedule Task { @MyGlobalActor }, before startSynchronously [thread:\(getCurrentThreadID())] @ :\(#line)")
-  let t1 = Task { @MyGlobalActor in
-    print("inside Task { @MyGlobalActor }, after sleep [thread:\(getCurrentThreadID())] @ :\(#line)")
-  }
-
-  print("before startSynchronously [thread:\(getCurrentThreadID())] @ :\(#line)")
-  let outerTID = getCurrentThreadID()
-  let tt = Task.startSynchronously { @MyGlobalActor in
-    let innerTID = getCurrentThreadID()
-    print("inside startSynchronously, outer thread = \(outerTID)")
-    print("inside startSynchronously, inner thread = \(innerTID)")
-    if (compareThreadIDs(outerTID, .notEqual, innerTID)) {
-      print("ERROR! Outer Thread ID must be equal Thread ID inside runSynchronously synchronous part!")
-    }
-
-    print("inside startSynchronously, sleep now [thread:\(getCurrentThreadID())] @ :\(#line)")
-    _ = try? await Task.sleep(for: .seconds(1))
-    print("after sleep, inside startSynchronously [thread:\(getCurrentThreadID())] @ :\(#line)")
-  }
-
-  return [t1, tt]
-}
-
-func syncOnNonTaskThread(synchronousTask behavior: SynchronousTaskBehavior) {
-  let sem1 = DispatchSemaphore(value: 0)
-  let sem2 = DispatchSemaphore(value: 0)
-  let queue = DispatchQueue(label: "CustomQueue")
-
-  queue.async {
-    // This is in order so we don't have a "current task" nor any "current executor"
-    print("before startSynchronously [thread:\(getCurrentThreadID())] @ :\(#line)")
-
-    let outerTID = getCurrentThreadID()
-    let tt = Task.startSynchronously {
-      dispatchPrecondition(condition: .onQueue(queue))
-
-      let innerTID = getCurrentThreadID()
-      if compareThreadIDs(outerTID, .notEqual, innerTID) {
-        print("inside startSynchronously, outer thread = \(outerTID)")
-        print("inside startSynchronously, inner thread = \(innerTID)")
-        print("ERROR! Outer Thread ID must be equal Thread ID inside runSynchronously synchronous part!")
-      }
-      print("inside startSynchronously [thread:\(getCurrentThreadID())] @ :\(#line)")
-
-      switch behavior {
-      case .suspend:
-        // sleep until woken up by outer task; i.e. actually suspend
-        print("inside startSynchronously, before sleep [thread:\(getCurrentThreadID())] @ :\(#line)")
-        _ = try? await Task.sleep(for: .seconds(10))
-        print("inside startSynchronously, after sleep [thread:\(getCurrentThreadID())] @ :\(#line)")
-      case .dontSuspend:
-        print("inside startSynchronously, done [thread:\(getCurrentThreadID())] @ :\(#line)")
-        ()
-      }
-      sem1.signal()
-    }
-    print("after startSynchronously, outside; cancel (wakeup) the synchronous task! [thread:\(getCurrentThreadID())] @ :\(#line)")
-    tt.cancel() // wake up the sleep
-
-    sem1.wait()
-    sem2.signal()
-  }
-
-  sem2.wait()
-}
-
-enum SynchronousTaskBehavior {
-  case suspend
-  case dontSuspend
-}
-
-print("\n\n==== ------------------------------------------------------------------")
-print("syncOnMyGlobalActor()")
-
-await Task { @MyGlobalActor in
-  MyGlobalActor.shared.preconditionIsolated("Should be executing on the global actor here")
-  for t in syncOnMyGlobalActor() {
-    await t.value
-  }
-}.value
-
-// CHECK-LABEL: syncOnMyGlobalActor()
-// CHECK: Confirmed to be on @MyGlobalActor
-// CHECK: schedule Task { @MyGlobalActor }, before startSynchronously [thread:[[CALLING_THREAD:.*]]]
-// CHECK: before startSynchronously [thread:[[CALLING_THREAD]]]
-// CHECK-NOT: ERROR!
-// CHECK: inside startSynchronously, sleep now
-// CHECK: inside Task { @MyGlobalActor }, after sleep
-// resume on some other thread
-// CHECK: after sleep, inside startSynchronously
-
-print("\n\n==== ------------------------------------------------------------------")
-var behavior: SynchronousTaskBehavior = .suspend
-print("syncOnNonTaskThread(synchronousTask: \(behavior))")
-syncOnNonTaskThread(synchronousTask: behavior)
-
-// CHECK-LABEL: syncOnNonTaskThread(synchronousTask: suspend)
-// No interleaving allowed between "before" and "inside":
-// CHECK-NEXT: before startSynchronously [thread:[[CALLING_THREAD2:.*]]]
-// CHECK-NOT: ERROR!
-// CHECK-NEXT: inside startSynchronously [thread:[[CALLING_THREAD2]]]
-// CHECK-NEXT: inside startSynchronously, before sleep [thread:[[CALLING_THREAD2]]]
-// CHECK-NEXT: after startSynchronously, outside; cancel (wakeup) the synchronous task!  [thread:[[CALLING_THREAD2]]]
-// CHECK-NEXT: inside startSynchronously, after sleep
-
-print("\n\n==== ------------------------------------------------------------------")
-behavior = .dontSuspend
-print("syncOnNonTaskThread(synchronousTask: \(behavior))")
-syncOnNonTaskThread(synchronousTask: behavior)
-
-// CHECK-LABEL: syncOnNonTaskThread(synchronousTask: dontSuspend)
-// CHECK-NEXT: before startSynchronously [thread:[[CALLING_THREAD3:.*]]]
-// CHECK-NOT: ERROR!
-// CHECK-NEXT: inside startSynchronously [thread:[[CALLING_THREAD3]]]
-// CHECK: inside startSynchronously, done [thread:[[CALLING_THREAD3]]]
-// CHECK: after startSynchronously, outside; cancel (wakeup) the synchronous task!  [thread:[[CALLING_THREAD3]]]
-
-print("\n\n==== ------------------------------------------------------------------")
-print("callActorFromStartSynchronousTask()")
-callActorFromStartSynchronousTask(recipient: .recipient(Recipient()))
-
-// CHECK: callActorFromStartSynchronousTask()
-// No interleaving allowed between "before" and "inside":
-// CHECK: before startSynchronously [thread:[[CALLING_THREAD4:.*]]]
-// CHECK-NEXT: inside startSynchronously [thread:[[CALLING_THREAD4]]]
-
-// It is important that as we suspend on the actor call, the 'after' startSynchronously gets to run
-// CHECK-NEXT: inside startSynchronously, call rec.sync() [thread:[[CALLING_THREAD4]]]
-// CHECK: after startSynchronously
-// CHECK-NOT: ERROR!
-// CHECK: inside startSynchronously, call rec.sync() done
-
-// CHECK-NOT: ERROR!
-// CHECK: inside startSynchronously, call rec.async()
-// CHECK-NOT: ERROR!
-// CHECK: inside startSynchronously, call rec.async() done
-
-// CHECK-NOT: ERROR!
-// CHECK: inside startSynchronously, done
-
-/// Don't want to involve protocol calls to not confuse the test with additional details,
-/// so we use concrete types here.
-enum TargetActorToCall {
-  case recipient(Recipient)
-  case recipientOnQueue(RecipientOnQueue)
-}
-
-protocol RecipientProtocol where Self: Actor {
-  func sync(syncTaskThreadID: ThreadID) async
-  func async(syncTaskThreadID: ThreadID) async
-}
-
-// default actor, must not declare an 'unownedExecutor'
-actor Recipient {
-  func sync(syncTaskThreadID: ThreadID) {
-    self.preconditionIsolated()
-
-    print("\(Recipient.self)/\(#function) Current actor thread id = \(getCurrentThreadID()) @ :\(#line)")
-    if compareThreadIDs(syncTaskThreadID, .equal, getCurrentThreadID()) {
-      print("NOTICE: Actor must not run on the synchronous task's thread :\(#line)")
-    }
-  }
-
-  func async(syncTaskThreadID: ThreadID) async {
-    self.preconditionIsolated()
-
-    // Dispatch may end up reusing the thread used to service the queue so we
-    // cannot truly assert exact thread identity in such tests.
-    // Usually this will be on a different thread by now though.
-    print("\(Recipient.self)/\(#function) Current actor thread id = \(getCurrentThreadID()) @ :\(#line)")
-    if compareThreadIDs(syncTaskThreadID, .equal, getCurrentThreadID()) {
-      print("NOTICE: Actor must not run on the synchronous task's thread :\(#line)")
-    }
-
-    await Task {
-      self.preconditionIsolated()
-    }.value
-  }
-}
-
-func callActorFromStartSynchronousTask(recipient rec: TargetActorToCall) {
-  let sem1 = DispatchSemaphore(value: 0)
-  let sem2 = DispatchSemaphore(value: 0)
-  let queue = DispatchQueue(label: "CustomQueue")
-
-  queue.async {
-    let outerTID = getCurrentThreadID()
-    print("before startSynchronously [thread:\(outerTID)] @ :\(#line)")
-    let tt = Task.startSynchronously {
-      dispatchPrecondition(condition: .onQueue(queue))
-
-      let innerTID = getCurrentThreadID()
-      precondition(compareThreadIDs(outerTID, .equal, innerTID), "Outer Thread ID must be equal Thread ID inside runSynchronously synchronous part!")
-      print("inside startSynchronously [thread:\(getCurrentThreadID())] @ :\(#line)")
-
-      for i in 1..<10 {
-        queue.async {
-          print("- async work on queue")
-        }
-      }
-
-      print("inside startSynchronously, call rec.sync() [thread:\(getCurrentThreadID())] @ :\(#line)")
-      switch rec {
-      case .recipient(let recipient): await recipient.sync(syncTaskThreadID: innerTID)
-      case .recipientOnQueue(let recipient): await recipient.sync(syncTaskThreadID: innerTID)
-      }
-      print("inside startSynchronously, call rec.sync() done [thread:\(getCurrentThreadID())] @ :\(#line)")
-
-      // after suspension we are supposed to hop off to the global pool,
-      // thus the thread IDs cannot be the same anymore
-      print("Inner thread id = \(innerTID)")
-      print("Current thread id = \(getCurrentThreadID())")
-      // Dispatch may end up reusing the thread used to service the queue so we
-      // cannot truly assert exact thread identity in such tests.
-      // Usually this will be on a different thread by now though.
-      if compareThreadIDs(innerTID, .equal, getCurrentThreadID()) {
-        print("NOTICE: Task resumed on same thread as it entered the synchronous task!")
-      }
-
-      print("inside startSynchronously, call rec.async() [thread:\(getCurrentThreadID())] @ :\(#line)")
-      switch rec {
-      case .recipient(let recipient): await recipient.async(syncTaskThreadID: innerTID)
-      case .recipientOnQueue(let recipient): await recipient.async(syncTaskThreadID: innerTID)
-      }
-      print("inside startSynchronously, call rec.async() done [thread:\(getCurrentThreadID())] @ :\(#line)")
-
-      print("Inner thread id = \(innerTID)")
-      print("Current thread id = \(getCurrentThreadID())")
-      // Dispatch may end up reusing the thread used to service the queue so we
-      // cannot truly assert exact thread identity in such tests.
-      // Usually this will be on a different thread by now though.
-      if compareThreadIDs(innerTID, .equal, getCurrentThreadID()) {
-        print("NOTICE: Task resumed on same thread as it entered the synchronous task!")
-      }
-
-      print("inside startSynchronously, done [thread:\(getCurrentThreadID())] @ :\(#line)")
-      sem1.signal()
-    }
-
-    print("after startSynchronously [thread:\(getCurrentThreadID())] @ :\(#line)")
-    sem2.signal()
-  }
-
-  sem1.wait()
-  sem2.wait()
-}
-
-print("\n\n==== ------------------------------------------------------------------")
-print("callActorFromStartSynchronousTask() - actor in custom executor with its own queue")
-let actorQueue = DispatchQueue(label: "recipient-actor-queue")
-callActorFromStartSynchronousTask(recipient: .recipientOnQueue(RecipientOnQueue(queue: actorQueue)))
-
-// CHECK-LABEL: callActorFromStartSynchronousTask() - actor in custom executor with its own queue
-// No interleaving allowed between "before" and "inside":
-// CHECK: before startSynchronously [thread:[[CALLING_THREAD4:.*]]]
-// CHECK-NEXT: inside startSynchronously [thread:[[CALLING_THREAD4]]]
-
-// As we call into an actor, we must enqueue to its custom executor;
-// Make sure the enqueue happens as expected and only then do we give up the calling thread
-// allowing the 'after startSynchronously' to run.
-//
-// CHECK-NEXT: inside startSynchronously, call rec.sync() [thread:[[CALLING_THREAD4]]]
-// CHECK: NaiveQueueExecutor(recipient-actor-queue) enqueue
-// CHECK: after startSynchronously
-// CHECK-NOT: ERROR!
-// CHECK: inside startSynchronously, call rec.sync() done
-
-// CHECK-NOT: ERROR!
-// CHECK: inside startSynchronously, call rec.async()
-// CHECK: NaiveQueueExecutor(recipient-actor-queue) enqueue
-// CHECK-NOT: ERROR!
-// CHECK: inside startSynchronously, call rec.async() done
-
-// CHECK-NOT: ERROR!
-// CHECK: inside startSynchronously, done
-
-final class NaiveQueueExecutor: SerialExecutor {
-  let queue: DispatchQueue
-
-  init(queue: DispatchQueue) {
-    self.queue = queue
-  }
-
-  public func enqueue(_ job: consuming ExecutorJob) {
-    let unowned = UnownedJob(job)
-    print("NaiveQueueExecutor(\(self.queue.label)) enqueue... [thread:\(getCurrentThreadID())]")
-    queue.async {
-    print("NaiveQueueExecutor(\(self.queue.label)) enqueue: run [thread:\(getCurrentThreadID())]")
-      unowned.runSynchronously(on: self.asUnownedSerialExecutor())
-    }
-  }
-}
-
-actor RecipientOnQueue {
-  let executor: NaiveQueueExecutor
-  nonisolated let unownedExecutor: UnownedSerialExecutor
-
-  init(queue: DispatchQueue) {
-    self.executor = NaiveQueueExecutor(queue: queue)
-    self.unownedExecutor = executor.asUnownedSerialExecutor()
-  }
-
-  func sync(syncTaskThreadID: ThreadID) {
-    self.preconditionIsolated()
-    dispatchPrecondition(condition: .onQueue(self.executor.queue))
-
-    print("\(Recipient.self)/\(#function) Current actor thread id = \(getCurrentThreadID()) @ :\(#line)")
-    if compareThreadIDs(syncTaskThreadID, .equal, getCurrentThreadID()) {
-      print("NOTICE: Actor must not run on the synchronous task's thread :\(#line)")
-    }
-  }
-
-  func async(syncTaskThreadID: ThreadID) async {
-    self.preconditionIsolated()
-    dispatchPrecondition(condition: .onQueue(self.executor.queue))
-
-    // Dispatch may end up reusing the thread used to service the queue so we
-    // cannot truly assert exact thread identity in such tests.
-    // Usually this will be on a different thread by now though.
-    print("\(Recipient.self)/\(#function) Current actor thread id = \(getCurrentThreadID()) @ :\(#line)")
-    if compareThreadIDs(syncTaskThreadID, .equal, getCurrentThreadID()) {
-      print("NOTICE: Actor must not run on the synchronous task's thread :\(#line)")
-    }
-
-    await Task {
-      self.preconditionIsolated()
-    }.value
-  }
-}
diff --git a/test/Concurrency/Runtime/task_creation.swift b/test/Concurrency/Runtime/task_creation.swift
index 42cf3d773e5a3..b834bc61719cd 100644
--- a/test/Concurrency/Runtime/task_creation.swift
+++ b/test/Concurrency/Runtime/task_creation.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library)
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/task_destruction.swift b/test/Concurrency/Runtime/task_destruction.swift
index f949727c6b789..20a026e584a57 100644
--- a/test/Concurrency/Runtime/task_destruction.swift
+++ b/test/Concurrency/Runtime/task_destruction.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift(-parse-as-library -target %target-swift-5.1-abi-triple) | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: concurrency_runtime
diff --git a/test/Concurrency/Runtime/taskgroup_cancelAll_cancellationHandler.swift b/test/Concurrency/Runtime/taskgroup_cancelAll_cancellationHandler.swift
index d242a15908c58..3249c2781f232 100644
--- a/test/Concurrency/Runtime/taskgroup_cancelAll_cancellationHandler.swift
+++ b/test/Concurrency/Runtime/taskgroup_cancelAll_cancellationHandler.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library) | %FileCheck %s
+// RUN: %target-run-simple-swift( -target %target-swift-5.1-abi-triple %import-libdispatch -parse-as-library -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)  | %FileCheck %s
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/Runtime/unspecified_is_main_actor.swift b/test/Concurrency/Runtime/unspecified_is_main_actor.swift
index 51c3a732079c2..18f389c0b3570 100644
--- a/test/Concurrency/Runtime/unspecified_is_main_actor.swift
+++ b/test/Concurrency/Runtime/unspecified_is_main_actor.swift
@@ -1,4 +1,6 @@
 // RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -swift-version 6 -g -import-objc-header %S/Inputs/RunOnMainActor.h %import-libdispatch -Xfrontend -default-isolation=MainActor )
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -swift-version 6 -g -import-objc-header %S/Inputs/RunOnMainActor.h %import-libdispatch -Xfrontend -default-isolation=MainActor  -swift-version 5 -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault)
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
diff --git a/test/Concurrency/ShrinkWrap.swift b/test/Concurrency/ShrinkWrap.swift
index 7450d0af773e8..1d7ad9ef71b68 100644
--- a/test/Concurrency/ShrinkWrap.swift
+++ b/test/Concurrency/ShrinkWrap.swift
@@ -5,6 +5,7 @@
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
+// REQUIRES: concurrency_runtime
 
 // rdar://124277662
 // XFAIL: freestanding
diff --git a/test/Concurrency/actor_call_implicitly_async.swift b/test/Concurrency/actor_call_implicitly_async.swift
index 6c79a12a0e994..b52b24718a616 100644
--- a/test/Concurrency/actor_call_implicitly_async.swift
+++ b/test/Concurrency/actor_call_implicitly_async.swift
@@ -168,7 +168,7 @@ func someAsyncFunc() async {
 
   _ = await a.deposit(b.withdraw(a.deposit(b.withdraw(b.balance()))))
 
-  // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}{{3-3=await }} expected-note@+1 {{call is 'async'}}
+  // expected-error@+1 {{actor-isolated instance method 'testSelfBalance()' cannot be called from outside of the actor}} {{3-3=await }}
   a.testSelfBalance()
 
   await a.testThrowing() // expected-error {{call can throw, but it is not marked with 'try' and the error is not handled}}
@@ -176,22 +176,22 @@ func someAsyncFunc() async {
   ////////////
   // effectful properties from outside the actor instance
 
-  // expected-warning@+2 {{non-sendable type 'Box' of property 'effPropA' cannot exit actor-isolated context}}
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}} {{7-7=await }} expected-note@+1{{property access is 'async'}}
+  // expected-warning@+2 {{non-Sendable type 'Box' of property 'effPropA' cannot exit actor-isolated context}}
+  // expected-error@+1{{actor-isolated property 'effPropA' cannot be accessed from outside of the actor}} {{7-7=await }}
   _ = a.effPropA
 
-  // expected-warning@+3 {{non-sendable type 'Box' of property 'effPropT' cannot exit actor-isolated context}}
+  // expected-warning@+3 {{non-Sendable type 'Box' of property 'effPropT' cannot exit actor-isolated context}}
   // expected-error@+2{{property access can throw, but it is not marked with 'try' and the error is not handled}}
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}} {{7-7=await }} expected-note@+1{{property access is 'async'}}
+  // expected-error@+1{{actor-isolated property 'effPropT' cannot be accessed from outside of the actor}} {{7-7=await }}
   _ = a.effPropT
 
   // expected-error@+2{{property access can throw, but it is not marked with 'try' and the error is not handled}}
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}} {{7-7=await }} expected-note@+1{{property access is 'async'}}
+  // expected-error@+1{{actor-isolated property 'effPropAT' cannot be accessed from outside of the actor}} {{7-7=await }}
   _ = a.effPropAT
 
   // (mostly) corrected ones
-  _ = await a.effPropA  // expected-warning {{non-sendable type 'Box' of property 'effPropA' cannot exit actor-isolated context}}
-  _ = try! await a.effPropT // expected-warning {{non-sendable type 'Box' of property 'effPropT' cannot exit actor-isolated context}}
+  _ = await a.effPropA  // expected-warning {{non-Sendable type 'Box' of property 'effPropA' cannot exit actor-isolated context}}
+  _ = try! await a.effPropT // expected-warning {{non-Sendable type 'Box' of property 'effPropT' cannot exit actor-isolated context}}
   _ = try? await a.effPropAT
 
   print("ok!")
@@ -204,9 +204,9 @@ func someAsyncFunc() async {
 
 extension BankAccount {
   func totalBalance(including other: BankAccount) async -> Int {
-    //expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{12-12=await }}
     return balance()
-          + other.balance()  // expected-note{{calls to instance method 'balance()' from outside of its actor context are implicitly asynchronous}}
+      + other.balance()
+    // expected-error@-1 {{actor-isolated instance method 'balance()' cannot be called from outside of the actor}}{{207:12-12=await }}
   }
 
   func breakAccounts(other: BankAccount) async {
@@ -223,11 +223,9 @@ func anotherAsyncFunc() async {
   let a = BankAccount(initialDeposit: 34)
   let b = BankAccount(initialDeposit: 35)
 
-  // expected-error@+2{{expression is 'async' but is not marked with 'await'}} {{7-7=await }}
-  // expected-note@+1{{calls to instance method 'deposit' from outside of its actor context are implicitly asynchronous}}
+  // expected-error@+1{{actor-isolated instance method 'deposit' cannot be called from outside of the actor}} {{7-7=await }}
   _ = a.deposit(1)
-  // expected-error@+2{{expression is 'async' but is not marked with 'await'}} {{7-7=await }}
-  // expected-note@+1{{calls to instance method 'balance()' from outside of its actor context are implicitly asynchronous}}
+  // expected-error@+1{{actor-isolated instance method 'balance()' cannot be called from outside of the actor}} {{7-7=await }}
   _ = b.balance()
 
   _ = b.balance // expected-error {{actor-isolated instance method 'balance()' can not be partially applied}}
@@ -235,7 +233,7 @@ func anotherAsyncFunc() async {
   // expected-error@+2{{actor-isolated property 'owner' can not be mutated from a nonisolated context}}
   // expected-note@+1{{consider declaring an isolated method on 'BankAccount' to perform the mutation}}
   a.owner = "cat"
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}} {{7-7=await }} expected-note@+1{{property access is 'async'}}
+  // expected-error@+1{{actor-isolated property 'owner' cannot be accessed from outside of the actor}} {{7-7=await }}
   _ = b.owner
   _ = await b.owner == "cat"
 
@@ -334,7 +332,7 @@ func walkChain(chain : Chain) async {
 
 @OrangeActor func quinoa() async {
 
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{3-3=await }} expected-note@+1 {{call is 'async'}}
+  // expected-error@+1{{global actor 'BananaActor'-isolated global function 'rice()' cannot be called from outside of the actor}}{{3-3=await }}
   rice()
 }
 
@@ -458,21 +456,21 @@ func tryEffPropsFromSync() {
 }
 
 @OrangeActor func tryEffPropertiesFromGlobalActor() async throws {
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{7-7=await }} expected-note@+1 {{property access is 'async'}}
+  // expected-error@+1{{global actor 'BananaActor'-isolated var 'effPropA' cannot be accessed from outside of the actor}}{{7-7=await }}
   _ = effPropA
 
   // expected-note@+5{{did you mean to handle error as optional value?}}
   // expected-note@+4{{did you mean to use 'try'?}}
   // expected-note@+3{{did you mean to disable error propagation?}}
   // expected-error@+2{{property access can throw but is not marked with 'try'}}
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{7-7=await }} expected-note@+1 {{property access is 'async'}}
+  // expected-error@+1{{global actor 'BananaActor'-isolated var 'effPropT' cannot be accessed from outside of the actor}}{{7-7=await }}
   _ = effPropT
 
   // expected-note@+5{{did you mean to handle error as optional value?}}
   // expected-note@+4{{did you mean to use 'try'?}}
   // expected-note@+3{{did you mean to disable error propagation?}}
   // expected-error@+2{{property access can throw but is not marked with 'try'}}
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{7-7=await }} expected-note@+1 {{property access is 'async'}}
+  // expected-error@+1{{global actor 'BananaActor'-isolated var 'effPropAT' cannot be accessed from outside of the actor}}{{7-7=await }}
   _ = effPropAT
 
   _ = await effPropA
@@ -494,7 +492,7 @@ actor SubscriptA {
 
   func f() async {
 
-    // expected-error@+1{{expression is 'async' but is not marked with 'await'}} {{9-9=await }} expected-note@+1{{subscript access is 'async'}}
+    // expected-error@+1{{actor-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}} {{9-9=await }}
     _ = self[0]
   }
 }
@@ -543,7 +541,7 @@ actor SubscriptAT {
 }
 
 func tryTheActorSubscripts(a : SubscriptA, t : SubscriptT, at : SubscriptAT) async throws {
-  // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}{{7-7=await }} expected-note@+1 {{subscript access is 'async'}}
+  // expected-error@+1 {{actor-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}}{{7-7=await }}
   _ = a[0]
 
   _ = await a[0]
@@ -552,7 +550,7 @@ func tryTheActorSubscripts(a : SubscriptA, t : SubscriptT, at : SubscriptAT) asy
   // expected-note@+4{{did you mean to use 'try'?}}
   // expected-note@+3{{did you mean to disable error propagation?}}
   // expected-error@+2{{subscript access can throw but is not marked with 'try'}}
-  // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}{{7-7=await }} expected-note@+1 {{subscript access is 'async'}}
+  // expected-error@+1 {{actor-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}}{{7-7=await }}
   _ = t[0]
 
   _ = try await t[0]
@@ -563,7 +561,7 @@ func tryTheActorSubscripts(a : SubscriptA, t : SubscriptT, at : SubscriptAT) asy
   // expected-note@+4{{did you mean to use 'try'?}}
   // expected-note@+3{{did you mean to disable error propagation?}}
   // expected-error@+2{{subscript access can throw but is not marked with 'try'}}
-  // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}{{7-7=await }} expected-note@+1 {{subscript access is 'async'}}
+  // expected-error@+1 {{actor-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}}{{7-7=await }}
   _ = at[0]
 
   _ = try await at[0]
@@ -583,8 +581,7 @@ final class IsolatedOperator: @preconcurrency Equatable {
 
   nonisolated func callEqual() async -> Bool {
     let foo = await IsolatedOperator()
-    // expected-error@+2{{expression is 'async' but is not marked with 'await'}}
-    // expected-note@+1{{calls to operator function '==' from outside of its actor context are implicitly asynchronous}}
+    // expected-error@+1{{main actor-isolated operator function '==' cannot be called from outside of the actor}} {{12-12=await }}
     return foo == self
   }
 }
diff --git a/test/Concurrency/actor_defer.swift b/test/Concurrency/actor_defer.swift
index fcda74b6184ee..ab97f7aed86d5 100644
--- a/test/Concurrency/actor_defer.swift
+++ b/test/Concurrency/actor_defer.swift
@@ -1,12 +1,10 @@
 // RUN: %target-swift-frontend -parse-as-library -emit-sil -DNEGATIVES -verify %s
 // RUN: %target-swift-frontend -parse-as-library -emit-sil -DNEGATIVES -verify %s -strict-concurrency=targeted
 // RUN: %target-swift-frontend -parse-as-library -emit-sil -DNEGATIVES -verify %s -strict-concurrency=complete
-// RUN: %target-swift-frontend -parse-as-library -emit-sil -DNEGATIVES -verify %s -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // RUN: %target-swift-frontend -parse-as-library -emit-sil -enable-actor-data-race-checks -o - %s | %FileCheck %s
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 func doSomething() {}
 
@@ -38,6 +36,16 @@ func testNonDefer_negative() {
 // CHECK-NEXT:    function_ref
 // CHECK-NEXT:    apply
 
+@MainActor func testGlobalActor_nested_positive() {
+  defer {
+    defer {
+      requiresMainActor()
+    }
+    doSomething()
+  }
+  doSomething()
+}
+
 #if NEGATIVES
 // expected-note @+1 {{add '@MainActor' to make global function 'testGlobalActor_negative()' part of global actor 'MainActor'}}
 func testGlobalActor_negative() {
diff --git a/test/Concurrency/actor_derived_conformances.swift b/test/Concurrency/actor_derived_conformances.swift
index f95069d033f6f..1590f613fc644 100644
--- a/test/Concurrency/actor_derived_conformances.swift
+++ b/test/Concurrency/actor_derived_conformances.swift
@@ -1,10 +1,8 @@
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=targeted
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=complete
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 actor A1: Comparable {}
 // expected-error@-1 {{type 'A1' does not conform to protocol 'Comparable'}}
diff --git a/test/Concurrency/actor_existentials.swift b/test/Concurrency/actor_existentials.swift
index 94b1a68862f80..24b52bbc9dcc6 100644
--- a/test/Concurrency/actor_existentials.swift
+++ b/test/Concurrency/actor_existentials.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 protocol P: Actor {
   func f()
diff --git a/test/Concurrency/actor_inout_isolation.swift b/test/Concurrency/actor_inout_isolation.swift
index d9d72beee7a6d..20ef27f4c3aed 100644
--- a/test/Concurrency/actor_inout_isolation.swift
+++ b/test/Concurrency/actor_inout_isolation.swift
@@ -1,5 +1,5 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-additional-prefix minimal-
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-additional-prefix targeted-complete-tns- -verify-additional-prefix complete-tns- -strict-concurrency=complete
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-additional-prefix complete- -strict-concurrency=complete
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
@@ -12,7 +12,7 @@
 //  - can't pass it into a curried/partially applied function
 //  - can't pass it inout to a function that doesn't directly touch it
 //  - can't pass it into a function that was passed into the calling method
-//  - can't call async mutating function on actor isolated state
+//  - can't call async mutating function on actor-isolated state
 
 struct Point {
   var x: Int
@@ -100,7 +100,7 @@ extension TestActor {
 // external class method call
 @available(SwiftStdlib 5.1, *)
 class NonAsyncClass {
-  // expected-targeted-complete-tns-note @-1 {{class 'NonAsyncClass' does not conform to the 'Sendable' protocol}}
+  // expected-complete-note @-1 {{class 'NonAsyncClass' does not conform to the 'Sendable' protocol}}
   // expected-tns-note @-2 {{class 'NonAsyncClass' does not conform to the 'Sendable' protocol}}
   func modifyOtherAsync(_ other : inout Int) async {
     // ...
@@ -119,7 +119,7 @@ extension TestActor {
   func passStateIntoDifferentClassMethod() async {
     let other = NonAsyncClass()
     let otherCurry = other.modifyOtherAsync
-    // expected-targeted-complete-tns-warning @-1 {{non-sendable type 'NonAsyncClass' cannot exit actor-isolated context in call to nonisolated instance method 'modifyOtherAsync'}}
+    // expected-complete-warning @-1 {{non-Sendable type 'NonAsyncClass' cannot exit actor-isolated context in call to nonisolated instance method 'modifyOtherAsync'}}
     await other.modifyOtherAsync(&value2)
     // expected-error @-1 {{actor-isolated property 'value2' cannot be passed 'inout' to 'async' function call}}
 
@@ -212,22 +212,22 @@ struct MyGlobalActor {
 // expected-note @-1 {{var declared here}}
 // expected-note @-2 {{var declared here}}
 // expected-note @-3 {{mutation of this var is only permitted within the actor}}
-// expected-complete-tns-error @-4 {{top-level code variables cannot have a global actor}}
-// expected-complete-tns-note @-5 4{{mutation of this var is only permitted within the actor}}
+// expected-complete-error @-4 {{top-level code variables cannot have a global actor}}
+// expected-complete-note @-5 4{{mutation of this var is only permitted within the actor}}
 
 
 if #available(SwiftStdlib 5.1, *) {
   let _ = Task.detached { await { (_ foo: inout Int) async in foo += 1 }(&number) }
   // expected-error @-1 {{actor-isolated var 'number' cannot be passed 'inout' to 'async' function call}}
   // expected-minimal-error @-2 {{global actor 'MyGlobalActor'-isolated var 'number' can not be used 'inout' from a nonisolated context}}
-  // expected-complete-tns-error @-3 {{main actor-isolated var 'number' can not be used 'inout' from a nonisolated context}}
+  // expected-complete-warning @-3 {{main actor-isolated var 'number' can not be used 'inout' from a nonisolated context}}
 }
 
 // attempt to pass global state owned by the global actor to another async function
 @available(SwiftStdlib 5.1, *)
 @MyGlobalActor func sneaky() async { await modifyAsynchronously(&number) }
 // expected-error @-1 {{actor-isolated var 'number' cannot be passed 'inout' to 'async' function call}}
-// expected-complete-tns-error @-2 {{main actor-isolated var 'number' can not be used 'inout' from global actor 'MyGlobalActor'}}
+// expected-complete-error @-2 {{main actor-isolated var 'number' can not be used 'inout' from global actor 'MyGlobalActor'}}
 
 
 // It's okay to pass actor state inout to synchronous functions!
@@ -237,13 +237,13 @@ func globalSyncFunction(_ foo: inout Int) { }
 @MyGlobalActor func globalActorSyncFunction(_ foo: inout Int) { }
 @available(SwiftStdlib 5.1, *)
 @MyGlobalActor func globalActorAsyncOkay() async { globalActorSyncFunction(&number) }
-// expected-complete-tns-error @-1 {{main actor-isolated var 'number' can not be used 'inout' from global actor 'MyGlobalActor'}}
+// expected-complete-error @-1 {{main actor-isolated var 'number' can not be used 'inout' from global actor 'MyGlobalActor'}}
 @available(SwiftStdlib 5.1, *)
 @MyGlobalActor func globalActorAsyncOkay2() async { globalSyncFunction(&number) }
-// expected-complete-tns-error @-1 {{main actor-isolated var 'number' can not be used 'inout' from global actor 'MyGlobalActor'}}
+// expected-complete-error @-1 {{main actor-isolated var 'number' can not be used 'inout' from global actor 'MyGlobalActor'}}
 @available(SwiftStdlib 5.1, *)
 @MyGlobalActor func globalActorSyncOkay() { globalSyncFunction(&number) }
-// expected-complete-tns-error @-1 {{main actor-isolated var 'number' can not be used 'inout' from global actor 'MyGlobalActor'}}
+// expected-complete-error @-1 {{main actor-isolated var 'number' can not be used 'inout' from global actor 'MyGlobalActor'}}
 
 // Gently unwrap things that are fine
 @available(SwiftStdlib 5.1, *)
@@ -288,11 +288,11 @@ actor ProtectArray {
   func test() async {
     // FIXME: this is invalid too!
     _ = await array.mutateAsynchronously
-    // expected-targeted-complete-tns-warning@-1 {{non-sendable type '@lvalue [Int]' cannot exit actor-isolated context in call to nonisolated property 'mutateAsynchronously'}}
+    // expected-complete-warning@-1 {{non-Sendable type '@lvalue [Int]' cannot exit actor-isolated context in call to nonisolated property 'mutateAsynchronously'}}
 
     _ = await array[mutateAsynchronously: 0]
     // expected-error@-1 {{actor-isolated property 'array' cannot be passed 'inout' to 'async' function call}}
-    // expected-targeted-complete-tns-warning@-2 {{non-sendable type 'inout Array<Int>' cannot exit actor-isolated context in call to nonisolated subscript 'subscript(mutateAsynchronously:)'}}
+    // expected-complete-warning@-2 {{non-Sendable type 'inout Array<Int>' cannot exit actor-isolated context in call to nonisolated subscript 'subscript(mutateAsynchronously:)'}}
 
     await passToAsync(array[0])
 
diff --git a/test/Concurrency/actor_isolation.swift b/test/Concurrency/actor_isolation.swift
index 19e1adf9c5945..d06d336f8f504 100644
--- a/test/Concurrency/actor_isolation.swift
+++ b/test/Concurrency/actor_isolation.swift
@@ -3,7 +3,7 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/OtherActors.swiftmodule -module-name OtherActors %S/Inputs/OtherActors.swift -target %target-swift-5.1-abi-triple
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/GlobalVariables.swiftmodule -module-name GlobalVariables %S/Inputs/GlobalVariables.swift -target %target-swift-5.1-abi-triple -parse-as-library
 
-// RUN: %target-swift-frontend -I %t  -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library -emit-sil -o /dev/null -verify -enable-upcoming-feature GlobalActorIsolatedTypesUsability %s
+// RUN: %target-swift-frontend -I %t  -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library -emit-sil -o /dev/null -verify -verify-ignore-unrelated -enable-upcoming-feature GlobalActorIsolatedTypesUsability %s
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
@@ -116,9 +116,8 @@ func checkAsyncPropertyAccess() async {
   act.text[0] += "hello" // expected-error{{actor-isolated property 'text' can not be mutated from a nonisolated context}}
   // expected-note@-1{{consider declaring an isolated method on 'MyActor' to perform the mutation}}
 
-  _ = act.point  // expected-warning{{non-sendable type 'Point' of property 'point' cannot exit actor-isolated context}}
-  // expected-warning@-1 {{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-2 {{property access is 'async'}}
+  _ = act.point  // expected-warning{{non-Sendable type 'Point' of property 'point' cannot exit actor-isolated context}}
+  // expected-warning@-1 {{actor-isolated property 'point' cannot be accessed from outside of the actor}} {{7-7=await }}
 }
 
 /// ------------------------------------------------------------------
@@ -156,20 +155,20 @@ func checkIsolationValueType(_ formance: InferredFromConformance,
                              _ ext: InferredFromContext,
                              _ anno: NoGlobalActorValueType) async {
   // these still do need an await in Swift 5
-  _ = await ext.point // expected-warning {{non-sendable type 'Point' of property 'point' cannot exit main actor-isolated context}}
-  _ = await anno.point // expected-warning {{non-sendable type 'Point' of property 'point' cannot exit global actor 'SomeGlobalActor'-isolated context}}
-  // expected-warning@-1 {{non-sendable type 'NoGlobalActorValueType' cannot be sent into global actor 'SomeGlobalActor'-isolated context in call to property 'point'}}
+  _ = await ext.point // expected-warning {{non-Sendable type 'Point' of property 'point' cannot exit main actor-isolated context}}
+  _ = await anno.point // expected-warning {{non-Sendable type 'Point' of property 'point' cannot exit global actor 'SomeGlobalActor'-isolated context}}
+  // expected-warning@-1 {{non-Sendable type 'NoGlobalActorValueType' cannot be sent into global actor 'SomeGlobalActor'-isolated context in call to property 'point'}}
 
   _ = formance.counter
   _ = anno.counter
 
   // these will always need an await
-  _ = await (formance as MainCounter).counter // expected-warning {{non-sendable type 'any MainCounter' cannot be sent into main actor-isolated context in call to property 'counter'}}
+  _ = await (formance as MainCounter).counter // expected-warning {{non-Sendable type 'any MainCounter' cannot be sent into main actor-isolated context in call to property 'counter'}}
   _ = await ext[1]
   _ = await formance.ticker
-  _ = await ext.polygon // expected-warning {{non-sendable type '[Point]' of property 'polygon' cannot exit main actor-isolated context}}
+  _ = await ext.polygon // expected-warning {{non-Sendable type '[Point]' of property 'polygon' cannot exit main actor-isolated context}}
   _ = await InferredFromContext.stuff
-  _ = await NoGlobalActorValueType.polygon // expected-warning {{non-sendable type '[Point]' of static property 'polygon' cannot exit main actor-isolated context}}
+  _ = await NoGlobalActorValueType.polygon // expected-warning {{non-Sendable type '[Point]' of static property 'polygon' cannot exit main actor-isolated context}}
 }
 
 // expected-warning@+2 {{memberwise initializer for 'NoGlobalActorValueType' cannot be both nonisolated and global actor 'SomeGlobalActor'-isolated; this is an error in the Swift 6 language mode}}
@@ -270,8 +269,7 @@ extension MyActor {
     // Accesses on other actors can only reference immutable data synchronously,
     // otherwise the access is treated as async
     _ = otherActor.immutable // okay
-    _ = otherActor.mutable  // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{property access is 'async'}}
+    _ = otherActor.mutable  // expected-error{{actor-isolated property 'mutable' cannot be accessed from outside of the actor}}{{9-9=await }}
     _ = await otherActor.mutable
     otherActor.mutable = 0  // expected-error{{actor-isolated property 'mutable' can not be mutated on a nonisolated actor instance}}
     // expected-note@-1{{consider declaring an isolated method on 'MyActor' to perform the mutation}}
@@ -282,12 +280,12 @@ extension MyActor {
     await otherActor.mutable = 0
 
     _ = otherActor.synchronous()
-    // expected-error@-1{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-2{{calls to instance method 'synchronous()' from outside of its actor context are implicitly asynchronous}}
+    // expected-error@-1{{actor-isolated instance method 'synchronous()' cannot be called from outside of the actor}}{{9-9=await }}
+
     _ = await otherActor.asynchronous()
     _ = otherActor.text[0]
-    // expected-error@-1{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-2{{property access is 'async'}}
+    // expected-error@-1{{actor-isolated property 'text' cannot be accessed from outside of the actor}}{{9-9=await }}
+
     _ = await otherActor.text[0] // okay
 
     // Global data is okay if it is immutable.
@@ -302,8 +300,7 @@ extension MyActor {
     Self.synchronousStatic()
 
     // Global actors
-    syncGlobalActorFunc() // expected-error{{expression is 'async' but is not marked with 'await'}}{{5-5=await }}
-    // expected-note@-1{{calls to global function 'syncGlobalActorFunc()' from outside of its actor context are implicitly asynchronous}}
+    syncGlobalActorFunc() // expected-error{{global actor 'SomeGlobalActor'-isolated global function 'syncGlobalActorFunc()' cannot be called from outside of the actor}}{{5-5=await }}
 
     await asyncGlobalActorFunc()
 
@@ -483,8 +480,7 @@ func crossIsolationBoundary(_ closure: () -> Void) async {}
 func testGlobalActorClosures() {
   let _: Int = acceptAsyncClosure { @SomeGlobalActor in
     syncGlobalActorFunc()
-    syncOtherGlobalActorFunc() // expected-error{{expression is 'async' but is not marked with 'await'}}{{5-5=await }}
-    // expected-note@-1{{calls to global function 'syncOtherGlobalActorFunc()' from outside of its actor context are implicitly asynchronous}}
+    syncOtherGlobalActorFunc() // expected-error{{global actor 'SomeOtherGlobalActor'-isolated global function 'syncOtherGlobalActorFunc()' cannot be called from outside of the actor}}{{5-5=await }}
 
     await syncOtherGlobalActorFunc()
     return 17
@@ -514,54 +510,43 @@ extension MyActor {
     await asyncOtherGlobalActorFunc()
 
     _ = immutable
-    _ = mutable // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{property access is 'async'}}
+    _ = mutable // expected-error{{actor-isolated property 'mutable' cannot be accessed from outside of the actor}}{{9-9=await }}
     _ = await mutable
-    _ = synchronous() // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{calls to instance method 'synchronous()' from outside of its actor context are implicitly asynchronous}}
+    _ = synchronous() // expected-error{{actor-isolated instance method 'synchronous()' cannot be called from outside of the actor}}{{9-9=await }}
     _ = await synchronous()
-    _ = text[0] // expected-error{{expression is 'async' but is not marked with 'await'}}
-    // expected-note@-1{{property access is 'async'}}
+    _ = text[0] // expected-error{{actor-isolated property 'text' cannot be accessed from outside of the actor}} {{9-9=await }}
 
     _ = await text[0]
 
     // Accesses on 'self' are only okay for immutable and asynchronous, because
     // we are outside of the actor instance.
     _ = self.immutable
-    _ = self.synchronous() // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{calls to instance method 'synchronous()' from outside of its actor context are implicitly asynchronous}}
+    _ = self.synchronous() // expected-error{{actor-isolated instance method 'synchronous()' cannot be called from outside of the actor}}{{9-9=await }}
     _ = await self.synchronous()
 
     _ = await self.asynchronous()
-    _ = self.text[0] // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{property access is 'async'}}
-    _ = self[0] // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{subscript access is 'async'}}
+    _ = self.text[0] // expected-error{{actor-isolated property 'text' cannot be accessed from outside of the actor}}{{9-9=await }}
+    _ = self[0] // expected-error{{actor-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}}{{9-9=await }}
     _ = await self.text[0]
     _ = await self[0]
 
     // Accesses on 'super' are not okay without 'await'; we're outside of the actor.
-    _ = super.superState // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{property access is 'async'}}
+    _ = super.superState // expected-error{{actor-isolated property 'superState' cannot be accessed from outside of the actor}}{{9-9=await }}
     _ = await super.superState
-    super.superMethod() // expected-error{{expression is 'async' but is not marked with 'await'}}{{5-5=await }}
-  // expected-note@-1{{calls to instance method 'superMethod()' from outside of its actor context are implicitly asynchronous}}
+    super.superMethod() // expected-error{{actor-isolated instance method 'superMethod()' cannot be called from outside of the actor}}{{5-5=await }}
 
     await super.superMethod()
     await super.superAsyncMethod()
-    _ = super[0] // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{subscript access is 'async'}}
+    _ = super[0] // expected-error{{actor-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}}{{9-9=await }}
     _ = await super[0]
 
     // Accesses on other actors can only reference immutable data or
     // call asynchronous methods
     _ = otherActor.immutable // okay
-    _ = otherActor.synchronous() // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{calls to instance method 'synchronous()' from outside of its actor context are implicitly asynchronous}}
+    _ = otherActor.synchronous() // expected-error{{actor-isolated instance method 'synchronous()' cannot be called from outside of the actor}}{{9-9=await }}
     _ = otherActor.synchronous  // expected-error{{actor-isolated instance method 'synchronous()' can not be partially applied}}
     _ = await otherActor.asynchronous()
-    _ = otherActor.text[0] // expected-error{{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-1{{property access is 'async'}}
+    _ = otherActor.text[0] // expected-error{{actor-isolated property 'text' cannot be accessed from outside of the actor}}{{9-9=await }}
     _ = await otherActor.text[0]
   }
 }
@@ -623,10 +608,8 @@ func testGlobalRestrictions(actor: MyActor) async {
   _ = actor.asynchronous
 
   // any kind of method can be called from outside the actor, so long as it's marked with 'await'
-  _ = actor.synchronous() // expected-error{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-  // expected-note@-1{{calls to instance method 'synchronous()' from outside of its actor context are implicitly asynchronous}}
-  _ = actor.asynchronous() // expected-error{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-  // expected-note@-1{{call is 'async'}}
+  _ = actor.synchronous() // expected-error{{actor-isolated instance method 'synchronous()' cannot be called from outside of the actor}}{{7-7=await }}
+  _ = actor.asynchronous() // expected-error{{actor-isolated instance method 'asynchronous()' cannot be called from outside of the actor}}{{7-7=await }}
 
   _ = await actor.synchronous()
   _ = await actor.asynchronous()
@@ -634,14 +617,11 @@ func testGlobalRestrictions(actor: MyActor) async {
   // stored and computed properties can be accessed. Only immutable stored properties can be accessed without 'await'
   _ = actor.immutable
   _ = await actor.immutable // expected-warning {{no 'async' operations occur within 'await' expression}}
-  _ = actor.mutable  // expected-error{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-  // expected-note@-1{{property access is 'async'}}
+  _ = actor.mutable  // expected-error{{actor-isolated property 'mutable' cannot be accessed from outside of the actor}}{{7-7=await }}
   _ = await actor.mutable
-  _ = actor.text[0] // expected-error{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-  // expected-note@-1{{property access is 'async'}}
+  _ = actor.text[0] // expected-error{{actor-isolated property 'text' cannot be accessed from outside of the actor}}{{7-7=await }}
   _ = await actor.text[0]
-  _ = actor[0] // expected-error{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-  // expected-note@-1{{subscript access is 'async'}}
+  _ = actor[0] // expected-error{{actor-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}}{{7-7=await }}
   _ = await actor[0]
 
   // nonisolated declarations are permitted.
@@ -669,8 +649,7 @@ func testGlobalRestrictions(actor: MyActor) async {
     _ = i
   }
 
-  print("\(number)") //expected-error {{expression is 'async' but is not marked with 'await'}}{{12-12=await }}
-  //expected-note@-1{{property access is 'async'}}
+  print("\(number)") //expected-error {{global actor 'SomeGlobalActor'-isolated var 'number' cannot be accessed from outside of the actor}}{{12-12=await }}
 
 }
 
@@ -734,7 +713,7 @@ func checkLocalFunctions() async {
   local1()
   local2()
 
-  // non-sendable closures don't cause problems.
+  // non-Sendable closures don't cause problems.
   acceptClosure {
     local1()
     local2()
@@ -742,7 +721,7 @@ func checkLocalFunctions() async {
 
   // Escaping closures can make the local function execute concurrently.
   acceptConcurrentClosure {
-    local2() // expected-warning{{capture of 'local2()' with non-sendable type '() -> ()' in a '@Sendable' closure}}
+    local2() // expected-warning{{capture of 'local2()' with non-Sendable type '() -> ()' in a '@Sendable' closure}}
     // expected-note@-1{{a function type must be marked '@Sendable' to conform to 'Sendable'}}
   }
 
@@ -752,7 +731,7 @@ func checkLocalFunctions() async {
   var k = 17
   func local4() {
     acceptConcurrentClosure {
-      local3() // expected-warning{{capture of 'local3()' with non-sendable type '() -> ()' in a '@Sendable' closure}}
+      local3() // expected-warning{{capture of 'local3()' with non-Sendable type '() -> ()' in a '@Sendable' closure}}
       // expected-note@-1{{a function type must be marked '@Sendable' to conform to 'Sendable'}}
     }
   }
@@ -834,31 +813,29 @@ actor LazyActor {
     lazy var l25: Int = { [unowned self] in self.l }()
 
     nonisolated lazy var l31: Int = { v }()
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
     // expected-warning@-2 {{actor-isolated default value in a nonisolated context; this is an error in the Swift 6 language mode}}
     nonisolated lazy var l32: Int = v
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
-    // expected-warning@-2 {{actor-isolated default value in a nonisolated context; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
     nonisolated lazy var l33: Int = { self.v }()
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
     // expected-warning@-2 {{actor-isolated default value in a nonisolated context; this is an error in the Swift 6 language mode}}
     nonisolated lazy var l34: Int = self.v
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
-    // expected-warning@-2 {{actor-isolated default value in a nonisolated context; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
     nonisolated lazy var l35: Int = { [unowned self] in self.v }()
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
     // expected-warning@-2 {{actor-isolated default value in a nonisolated context; this is an error in the Swift 6 language mode}}
 
     nonisolated lazy var l41: Int = { l }()
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
     nonisolated lazy var l42: Int = l
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
     nonisolated lazy var l43: Int = { self.l }()
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
     nonisolated lazy var l44: Int = self.l
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
     nonisolated lazy var l45: Int = { [unowned self] in self.l }()
-    // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
+    // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
 }
 
 // Infer global actors from context only for instance members.
@@ -889,7 +866,7 @@ actor SomeActorWithInits {
   // expected-note@+1 {{mutation of this property is only permitted within the actor}}
   let nonSendable: SomeClass
 
-  // Sema should not complain about referencing non-sendable members
+  // Sema should not complain about referencing non-Sendable members
   // in an actor init or deinit, as those are diagnosed later by flow-isolation.
   init(_ x: SomeClass) {
     self.nonSendable = x
@@ -1053,8 +1030,7 @@ class SomeClassWithInits {
       // okay
       await self.isolated()
       self.isolated()
-      // expected-error@-1{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-      // expected-note@-2{{calls to instance method 'isolated()' from outside of its actor context are implicitly asynchronous}}
+      // expected-error@-1{{main actor-isolated instance method 'isolated()' cannot be called from outside of the actor}}{{7-7=await }}
 
       print(await self.mutableState)
     }
@@ -1072,14 +1048,12 @@ func outsideSomeClassWithInits() { // expected-note 3 {{add '@MainActor' to make
 // nonisolated let and cross-module let
 // ----------------------------------------------------------------------
 func testCrossModuleLets(actor: OtherModuleActor) async {
-  _ = actor.a         // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{property access is 'async'}}
+  _ = actor.a         // expected-error{{actor-isolated property 'a' cannot be accessed from outside of the actor}} {{7-7=await }}
   _ = await actor.a   // okay
   _ = actor.b         // okay
-  _ = actor.c // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{property access is 'async'}}
-  // expected-warning@-2{{non-sendable type 'SomeClass' of property 'c' cannot exit actor-isolated context}}
-  _ = await actor.c // expected-warning{{non-sendable type 'SomeClass' of property 'c' cannot exit actor-isolated context}}
+  _ = actor.c // expected-error{{actor-isolated property 'c' cannot be accessed from outside of the actor}} {{7-7=await }}
+  // expected-warning@-1{{non-Sendable type 'SomeClass' of property 'c' cannot exit actor-isolated context}}
+  _ = await actor.c // expected-warning{{non-Sendable type 'SomeClass' of property 'c' cannot exit actor-isolated context}}
   _ = await actor.d // okay
 }
 
@@ -1108,14 +1082,12 @@ actor CrossModuleFromInitsActor {
   }
 
   init(v2 actor: OtherModuleActor) async {
-    _ = actor.a         // expected-error{{expression is 'async' but is not marked with 'await'}}
-    // expected-note@-1{{property access is 'async'}}
+    _ = actor.a         // expected-error{{actor-isolated property 'a' cannot be accessed from outside of the actor}} {{9-9=await }}
     _ = await actor.a   // okay
     _ = actor.b         // okay
-    _ = actor.c // expected-error{{expression is 'async' but is not marked with 'await'}}
-    // expected-note@-1{{property access is 'async'}}
-    // expected-warning@-2{{non-sendable type 'SomeClass' of property 'c' cannot exit actor-isolated context}}
-    _ = await actor.c // expected-warning{{non-sendable type 'SomeClass' of property 'c' cannot exit actor-isolated context}}
+    _ = actor.c // expected-error{{actor-isolated property 'c' cannot be accessed from outside of the actor}} {{9-9=await }}
+    // expected-warning@-1{{non-Sendable type 'SomeClass' of property 'c' cannot exit actor-isolated context}}
+    _ = await actor.c // expected-warning{{non-Sendable type 'SomeClass' of property 'c' cannot exit actor-isolated context}}
     _ = await actor.d // okay
   }
 }
@@ -1183,11 +1155,9 @@ func testCrossActorProtocol<T: P>(t: T) async {
   await t.f()
   await t.g()
   t.f()
-  // expected-error@-1{{expression is 'async' but is not marked with 'await'}}{{3-3=await }}
-  // expected-note@-2{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+  // expected-error@-1{{actor-isolated instance method 'f()' cannot be called from outside of the actor}}{{3-3=await }}
   t.g()
-  // expected-error@-1{{expression is 'async' but is not marked with 'await'}}{{3-3=await }}
-  // expected-note@-2{{calls to instance method 'g()' from outside of its actor context are implicitly asynchronous}}
+  // expected-error@-1{{actor-isolated instance method 'g()' cannot be called from outside of the actor}}{{3-3=await }}
   ASP.s()
   ASPD.sd()
 }
@@ -1210,6 +1180,8 @@ actor MyServer : Server {
 func acceptAsyncSendableClosure<T>(_: @Sendable () async -> T) { }
 @available(SwiftStdlib 5.1, *)
 func acceptAsyncSendableClosureInheriting<T>(@_inheritActorContext _: @Sendable () async -> T) { }
+@available(SwiftStdlib 5.1, *)
+func acceptAsyncSendableClosureInheritingAlways<T>(@_inheritActorContext(always) _: @Sendable () async -> T) { }
 
 @available(SwiftStdlib 5.1, *)
 extension MyActor {
@@ -1217,8 +1189,7 @@ extension MyActor {
     var counter = 0
 
     acceptAsyncSendableClosure {
-      _ = synchronous() // expected-error{{expression is 'async' but is not marked with 'await'}}
-      // expected-note@-1{{calls to instance method 'synchronous()' from outside of its actor context are implicitly asynchronous}}
+      _ = synchronous() // expected-error{{actor-isolated instance method 'synchronous()' cannot be called from outside of the actor}} {{11-11=await }}
 
       counter += 1 // expected-warning{{mutation of captured var 'counter' in concurrently-executing code}}
     }
@@ -1237,6 +1208,10 @@ extension MyActor {
       _ = await synchronous() // expected-warning{{no 'async' operations occur within 'await' expression}}
       counter += 1 // okay
     }
+
+    acceptAsyncSendableClosureInheritingAlways {
+      counter += 1 // Ok
+    }
   }
 }
 
@@ -1257,6 +1232,32 @@ func testGlobalActorInheritance() {
   acceptAsyncSendableClosureInheriting {
     counter += 1 // ok
   }
+
+  acceptAsyncSendableClosureInheritingAlways {
+    counter += 1 // ok
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+func testIsolatedParameter1(_: isolated any Actor, v: inout Int) {
+  acceptAsyncSendableClosureInheriting {
+    v += 1 // expected-warning {{mutable capture of 'inout' parameter 'v' is not allowed in concurrently-executing code}}
+  }
+
+  acceptAsyncSendableClosureInheritingAlways {
+    v += 1 // Ok
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+func testIsolatedParameter2(_: isolated (any Actor)? = #isolation, v: inout Int) {
+  acceptAsyncSendableClosureInheriting {
+    v += 1 // expected-warning {{mutable capture of 'inout' parameter 'v' is not allowed in concurrently-executing code}}
+  }
+
+  acceptAsyncSendableClosureInheritingAlways {
+    v += 1 // Ok
+  }
 }
 
 @available(SwiftStdlib 5.1, *)
@@ -1264,11 +1265,11 @@ func testGlobalActorInheritance() {
 protocol GloballyIsolatedProto {
 }
 
-// rdar://75849035 - trying to conform an actor to a global-actor isolated protocol should result in an error
+// rdar://75849035 - trying to conform an actor to a global-actor-isolated protocol should result in an error
 func test_conforming_actor_to_global_actor_protocol() {
   @available(SwiftStdlib 5.1, *)
   actor MyValue : GloballyIsolatedProto {}
-  // expected-error@-1 {{actor 'MyValue' cannot conform to global actor isolated protocol 'GloballyIsolatedProto'}}
+  // expected-error@-1 {{actor 'MyValue' cannot conform to global-actor-isolated protocol 'GloballyIsolatedProto'}}
 }
 
 func test_nonisolated_variable() {
@@ -1387,12 +1388,10 @@ func take(_ val: SelfParamIsolationNonMethod) {}
 
 actor SelfParamIsolationNonMethod {
   init(s0: Void) {
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{44-44=await }}
     acceptAsyncSendableClosureInheriting { self.f() }
 
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{34-34=await }}
     acceptAsyncSendableClosure { self.f() }
 
     // expected-error@+1 {{call to actor-isolated global function 'takeIsolated' in a synchronous nonisolated context}}
@@ -1402,20 +1401,17 @@ actor SelfParamIsolationNonMethod {
   }
 
   @MainActor init(s1: Void) {
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{44-44=await }}
     acceptAsyncSendableClosureInheriting { self.f() }
 
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{34-34=await }}
     acceptAsyncSendableClosure { self.f() }
   }
 
   init(a1: Void) async {
     acceptAsyncSendableClosureInheriting { self.f() }
 
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{34-34=await }}
     acceptAsyncSendableClosure { self.f() }
 
     takeIsolated(self)
@@ -1424,32 +1420,26 @@ actor SelfParamIsolationNonMethod {
   }
 
   @MainActor init(a2: Void) async {
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{44-44=await }}
     acceptAsyncSendableClosureInheriting { self.f() }
 
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{34-34=await }}
     acceptAsyncSendableClosure { self.f() }
   }
 
   nonisolated init(a3: Void) async {
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{44-44=await }}
     acceptAsyncSendableClosureInheriting { self.f() }
 
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{34-34=await }}
     acceptAsyncSendableClosure { self.f() }
   }
 
   deinit {
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{44-44=await }}
     acceptAsyncSendableClosureInheriting { self.f() }
 
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{34-34=await }}
     acceptAsyncSendableClosure { self.f() }
 
     // expected-error@+1 {{call to actor-isolated global function 'takeIsolated' in a synchronous nonisolated context}}
@@ -1466,18 +1456,15 @@ final class MainActorInit: Sendable {
   init() {
     acceptAsyncSendableClosureInheriting { self.f() }
 
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{34-34=await }}
     acceptAsyncSendableClosure { self.f() }
   }
 
   deinit {
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{44-44=await }}
     acceptAsyncSendableClosureInheriting { self.f() }
 
-    // expected-note@+2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-    // expected-error@+1 {{expression is 'async' but is not marked with 'await'}}
+    // expected-error@+1 {{actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{34-34=await }}
     acceptAsyncSendableClosure { self.f() }
   }
 
@@ -1647,9 +1634,8 @@ class ReferenceActor {
   init() async {
     self.a = ProtectNonSendable()
 
-    // expected-warning@+3 {{non-sendable type 'NonSendable' of property 'ns' cannot exit actor-isolated context}}
-    // expected-warning@+2 {{expression is 'async' but is not marked with 'await'}}
-    // expected-note@+1 {{property access is 'async'}}
+    // expected-warning@+2 {{non-Sendable type 'NonSendable' of property 'ns' cannot exit actor-isolated context}}
+    // expected-warning@+1 {{actor-isolated property 'ns' cannot be accessed from outside of the actor}} {{9-9=await }}
     _ = a.ns
   }
 }
@@ -1732,7 +1718,7 @@ struct ReferenceSelfDotMethods {
   private func testCurry() -> (Self) -> (@MainActor () -> Void) {
     let functionRef = Self.mainActorAffinedFunction
     // warning goes away with InferSendableFromCaptures, see actor_isolation_swift6.swift
-    return functionRef // expected-warning {{converting non-sendable function value to '@MainActor @Sendable () -> Void' may introduce data races}}
+    return functionRef // expected-warning {{converting non-Sendable function value to '@MainActor @Sendable () -> Void' may introduce data races}}
   }
 
   @MainActor
@@ -1763,4 +1749,30 @@ actor UserDefinedActorSelfDotMethod {
     // error message changes with InferSendabaleFromCaptures - see actor_isolation_swift6.swift
     return functionRef // expected-error {{cannot convert return expression of type '(isolated Self) -> () -> ()' to return type '(UserDefinedActorSelfDotMethod) -> @isolated(any) () -> Void'}}
   }
-}
\ No newline at end of file
+}
+
+func requireSendableInheritContext(@_inheritActorContext _: @Sendable () -> ()) {}
+// expected-warning@-1 {{@_inheritActorContext only applies to '@isolated(any)' parameters or parameters with asynchronous function types; this will be an error in a future Swift language mode}}
+
+actor InvalidInheritedActorIsolation {
+  func actorFunction() {} // expected-note {{calls to instance method 'actorFunction()' from outside of its actor context are implicitly asynchronous}}
+
+  func test() {
+    requireSendableInheritContext {
+      self.actorFunction()
+      // expected-error@-1 {{call to actor-isolated instance method 'actorFunction()' in a synchronous nonisolated context}}
+    }
+  }
+}
+
+@MainActor
+class InvalidInheritedGlobalActorIsolation {
+  func mainActorFunction() {} // expected-note {{calls to instance method 'mainActorFunction()' from outside of its actor context are implicitly asynchronous}}
+
+  func test() {
+    requireSendableInheritContext {
+      self.mainActorFunction()
+      // expected-error@-1 {{call to main actor-isolated instance method 'mainActorFunction()' in a synchronous nonisolated context}}
+    }
+  }
+}
diff --git a/test/Concurrency/actor_isolation_cycle.swift b/test/Concurrency/actor_isolation_cycle.swift
index 5fdfefadf4a97..c569f0de5532e 100644
--- a/test/Concurrency/actor_isolation_cycle.swift
+++ b/test/Concurrency/actor_isolation_cycle.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 public protocol P {
   associatedtype T
diff --git a/test/Concurrency/actor_isolation_objc.swift b/test/Concurrency/actor_isolation_objc.swift
index 2d2503bce1aab..0dc3c8718fa19 100644
--- a/test/Concurrency/actor_isolation_objc.swift
+++ b/test/Concurrency/actor_isolation_objc.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
 // REQUIRES: objc_interop
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 import Foundation
 
@@ -36,10 +34,10 @@ actor A {
   var x: Int = 0 // expected-note{{add '@objc' to expose this property to Objective-C}}
 
   @objc var y: Int = 0 // expected-note{{add '@objc' to expose this property to Objective-C}}
-  // expected-error@-1{{actor-isolated property 'y' cannot be @objc}}
+  // expected-error@-1{{actor-isolated property 'y' cannot be '@objc'}}
 
   // expected-note@+1 {{add '@objc' to expose this property to Objective-C}}
-  @objc var computed : Int { // expected-error{{actor-isolated property 'computed' cannot be @objc}}
+  @objc var computed : Int { // expected-error{{actor-isolated property 'computed' cannot be '@objc'}}
     get { 120 }
   }
 
@@ -50,7 +48,7 @@ actor A {
 
 actor Dril: NSObject {
   // expected-note@+2 {{add 'async' to function 'postSynchronouslyTo(twitter:)' to make it asynchronous}}
-  // expected-error@+1 {{actor-isolated instance method 'postSynchronouslyTo(twitter:)' cannot be @objc}}
+  // expected-error@+1 {{actor-isolated instance method 'postSynchronouslyTo(twitter:)' cannot be '@objc'}}
   @objc func postSynchronouslyTo(twitter msg: String) -> Bool {
     return true
   }
@@ -67,5 +65,7 @@ actor Pumpkin: NSObject {}
 
 actor Bad {
   @objc nonisolated lazy var invalid = 0
-  // expected-warning@-1 {{'nonisolated' is not supported on lazy properties; this is an error in the Swift 6 language mode}}
+  // expected-warning@-1 {{'nonisolated' cannot be applied to mutable stored properties; this is an error in the Swift 6 language mode}}
+  // expected-error@-2 {{actor-isolated setter for property 'invalid' cannot be '@objc'}}
+  // expected-error@-3 {{actor-isolated getter for property 'invalid' cannot be '@objc'}}
 }
diff --git a/test/Concurrency/actor_isolation_swift6.swift b/test/Concurrency/actor_isolation_swift6.swift
index 1c8c2110d01b3..d724c15c79be5 100644
--- a/test/Concurrency/actor_isolation_swift6.swift
+++ b/test/Concurrency/actor_isolation_swift6.swift
@@ -65,7 +65,7 @@ func checkIsolationValueType(_ formance: InferredFromConformance,
 
   // these do need await, regardless of reference or value type
   _ = await (formance as any MainCounter).counter
-  // expected-error@-1 {{non-sendable type 'any MainCounter' cannot be sent into main actor-isolated context in call to property 'counter'}}
+  // expected-error@-1 {{non-Sendable type 'any MainCounter' cannot be sent into main actor-isolated context in call to property 'counter'}}
   _ = await ext[1]
   _ = await formance.ticker
   _ = await ext.polygon
diff --git a/test/Concurrency/actor_isolation_unsafe.swift b/test/Concurrency/actor_isolation_unsafe.swift
index b026c2720509b..d5f6f1b8108d2 100644
--- a/test/Concurrency/actor_isolation_unsafe.swift
+++ b/test/Concurrency/actor_isolation_unsafe.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-additional-prefix complete-tns- -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-additional-prefix complete-tns- -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-additional-prefix complete- -strict-concurrency=complete
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @globalActor
 actor SomeGlobalActor {
@@ -16,7 +14,7 @@ actor SomeGlobalActor {
 
 // expected-warning@+1 {{'(unsafe)' global actors are deprecated; use '@preconcurrency' instead}}
 @SomeGlobalActor(unsafe) func globalSome() { } // expected-note 2{{calls to global function 'globalSome()' from outside of its actor context are implicitly asynchronous}}
-// expected-complete-tns-note @-1 {{calls to global function 'globalSome()' from outside of its actor context are implicitly asynchronous}}
+// expected-complete-note @-1 {{calls to global function 'globalSome()' from outside of its actor context are implicitly asynchronous}}
 
 // ----------------------------------------------------------------------
 // Witnessing and unsafe global actor
@@ -58,15 +56,15 @@ struct S4_P1: P1 {
 @MainActor(unsafe)
 protocol P2 {
   func f() // expected-note{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-  // expected-complete-tns-note @-1 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+  // expected-complete-note @-1 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
   nonisolated func g()
 }
 
 struct S5_P2: P2 {
   func f() { } // expected-note{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
   // expected-note@-1 {{main actor isolation inferred from conformance to protocol 'P2'}}
-  // expected-complete-tns-note @-2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
-  // expected-complete-tns-note @-3 {{main actor isolation inferred from conformance to protocol 'P2'}}}
+  // expected-complete-note @-2 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+  // expected-complete-note @-3 {{main actor isolation inferred from conformance to protocol 'P2'}}}
   func g() { }
 }
 
@@ -78,12 +76,12 @@ nonisolated func testP2(x: S5_P2, p2: P2) {
 }
 
 func testP2_noconcurrency(x: S5_P2, p2: P2) {
-  // expected-complete-tns-note @-1 2{{add '@MainActor' to make global function 'testP2_noconcurrency(x:p2:)' part of global actor 'MainActor'}}
+  // expected-complete-note @-1 2{{add '@MainActor' to make global function 'testP2_noconcurrency(x:p2:)' part of global actor 'MainActor'}}
   p2.f() // okay without complete. with targeted/minimal not concurrency-related code.
-  // expected-complete-tns-warning @-1 {{call to main actor-isolated instance method 'f()' in a synchronous nonisolated context}}
+  // expected-complete-warning @-1 {{call to main actor-isolated instance method 'f()' in a synchronous nonisolated context}}
   p2.g() // okay
   x.f() // okay without complete. with targeted/minimal not concurrency-related code
-  // expected-complete-tns-warning @-1 {{call to main actor-isolated instance method 'f()' in a synchronous nonisolated context}}
+  // expected-complete-warning @-1 {{call to main actor-isolated instance method 'f()' in a synchronous nonisolated context}}
   x.g() // OKAY
 }
 
@@ -98,7 +96,7 @@ class C1 {
 class C2: C1 {
   override func method() { // expected-note 2{{overridden declaration is here}}
     globalSome() // okay when not in complete
-    // expected-complete-tns-warning @-1 {{call to global actor 'SomeGlobalActor'-isolated global function 'globalSome()' in a synchronous main actor-isolated context}}
+    // expected-complete-warning @-1 {{call to global actor 'SomeGlobalActor'-isolated global function 'globalSome()' in a synchronous main actor-isolated context}}
   }
 }
 
@@ -138,8 +136,8 @@ class C7: C2 {
 protocol GloballyIsolatedProto {
 }
 
-// rdar://75849035 - trying to conform an actor to a global-actor isolated protocol should result in an error
+// rdar://75849035 - trying to conform an actor to a global-actor-isolated protocol should result in an error
 func test_conforming_actor_to_global_actor_protocol() {
   actor MyValue : GloballyIsolatedProto {}
-  // expected-error@-1 {{actor 'MyValue' cannot conform to global actor isolated protocol 'GloballyIsolatedProto'}}
+  // expected-error@-1 {{actor 'MyValue' cannot conform to global-actor-isolated protocol 'GloballyIsolatedProto'}}
 }
diff --git a/test/Concurrency/actor_keypath_isolation.swift b/test/Concurrency/actor_keypath_isolation.swift
index 0327cd629dace..2782973fcdffe 100644
--- a/test/Concurrency/actor_keypath_isolation.swift
+++ b/test/Concurrency/actor_keypath_isolation.swift
@@ -1,8 +1,6 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete %s -emit-sil -o /dev/null -verify
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 class Box {
     let size : Int = 0
diff --git a/test/Concurrency/actor_withCancellationHandler.swift b/test/Concurrency/actor_withCancellationHandler.swift
index 182e1c895e5c2..39e0dca72f41c 100644
--- a/test/Concurrency/actor_withCancellationHandler.swift
+++ b/test/Concurrency/actor_withCancellationHandler.swift
@@ -2,10 +2,8 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/OtherActors.swiftmodule -module-name OtherActors %S/Inputs/OtherActors.swift -target %target-swift-5.1-abi-triple
 
 // RUN: %target-swift-frontend -I %t  -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify
-// RUN: %target-swift-frontend -I %t  -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 actor Foo {
   var t: Task<Void, Error>?
diff --git a/test/Concurrency/assume_mainactor.swift b/test/Concurrency/assume_mainactor.swift
index 5ac53cb6bc911..6e3dc002b66ae 100644
--- a/test/Concurrency/assume_mainactor.swift
+++ b/test/Concurrency/assume_mainactor.swift
@@ -8,13 +8,14 @@
 class Klass {
   // Implicit deinit
   // CHECK: // Klass.deinit
-  // CHECK-NEXT: // Isolation: unspecified
+  // CHECK-NEXT: // Isolation: global_actor. type: MainActor
   // CHECK-NEXT: sil hidden [ossa] @$s16assume_mainactor5KlassCfd : $@convention(method) (@guaranteed Klass) -> @owned Builtin.NativeObject {
 
   // Implicit deallocating deinit
   // CHECK: // Klass.__deallocating_deinit
   // CHECK-NEXT: // Isolation: nonisolated
   // CHECK-NEXT: sil hidden [ossa] @$s16assume_mainactor5KlassCfD : $@convention(method) (@owned Klass) -> () {
+  // CHECK: swift_task_deinitOnExecutor
 
   // Implicit allocating init
   // CHECK: // Klass.__allocating_init()
@@ -66,6 +67,16 @@ struct NonIsolatedStructContainingKlass {
   // CHECK-NEXT: sil hidden [ossa] @$s16assume_mainactor32NonIsolatedStructContainingKlassVACycfC : $@convention(method) (@thin NonIsolatedStructContainingKlass.Type) -> @owned NonIsolatedStructContainingKlass {
 }
 
+struct NonCopyableStruct: ~Copyable {
+  var x: Int
+  var y: Int
+
+  // CHECK: NonCopyableStruct.deinit
+  // CHECK-NEXT: Isolation: nonisolated
+  deinit {
+  }
+}
+
 @globalActor
 actor CustomActor {
   static nonisolated let shared = CustomActor()
@@ -215,3 +226,52 @@ actor MyActor2 {
   // NonIsolated and not if print was inferred to be main actor.
   print("123")
 }
+
+nonisolated func localDeclIsolation() async {
+  struct Local {
+    static func f() {}
+  }
+
+  Local.f()
+
+  await withTaskGroup { group in
+    group.addTask { }
+
+    await group.next()
+  }
+}
+
+@CustomActor
+class CustomActorIsolated {
+  struct Nested {
+    // CHECK: // static CustomActorIsolated.Nested.f()
+    // CHECK-NEXT: // Isolation: unspecified
+    static func f() {}
+  }
+
+  // CHECK: // CustomActorIsolated.customIsolated()
+  // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
+  func customIsolated() {
+    Nested.f()
+  }
+}
+
+var global = 0
+
+func onMain() async {
+  await withTaskGroup { group in
+    group.addTask { }
+
+    await group.next()
+  }
+
+  struct Nested {
+    // CHECK: // static useGlobal() in Nested #1 in onMain()
+    // CHECK-NEXT: // Isolation: global_actor. type: MainActor
+    static func useGlobal() -> Int {
+      global
+    }
+  }
+
+  _ = Nested.useGlobal()
+}
diff --git a/test/Concurrency/assume_mainactor_typechecker_errors.swift b/test/Concurrency/assume_mainactor_typechecker_errors.swift
index 7ca7f42af09c6..1f5e1066f3c35 100644
--- a/test/Concurrency/assume_mainactor_typechecker_errors.swift
+++ b/test/Concurrency/assume_mainactor_typechecker_errors.swift
@@ -1,19 +1,27 @@
-// RUN: %target-swift-frontend -swift-version 6 -emit-sil -default-isolation MainActor %s -verify
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -swift-version 6 -module-name implicit_nonisolated_things -o %t/implicit_nonisolated_things.swiftmodule %S/Inputs/implicit_nonisolated_things.swift
+// RUN: %target-swift-frontend -I %t -swift-version 5 -emit-sil -default-isolation MainActor %s -verify -verify-additional-prefix swift5-
+// RUN: %target-swift-frontend -I %t  -swift-version 6 -emit-sil -default-isolation MainActor %s -verify -verify-additional-prefix swift6-
 
 // READ THIS! This test is meant to check the specific isolation when
 // `-default-isolation` is set to `MainActor` in combination with validating
 // behavior around explicitly non-Sendable types that trigger type checker
 // specific errors. Please do not put other types of tests in here.
 
+import implicit_nonisolated_things
+
 // Fake Sendable Data
 class SendableData : @unchecked Sendable {}
+// expected-swift5-note@-1 {{calls to initializer 'init()' from outside of its actor context are implicitly asynchronous}}
 
 nonisolated func getDataFromSocket() -> SendableData { SendableData() }
+// expected-swift5-warning@-1 {{call to main actor-isolated initializer 'init()' in a synchronous nonisolated context}}
 
-class Klass { // expected-note 3 {{}}
+class Klass { // expected-swift5-note 3 {{}} expected-swift6-note 3 {{}}
   let s = SendableData()
+  // expected-swift5-note@-1 2 {{}}
 
-  init() { s = SendableData() }
+  init() { s = SendableData() } // expected-swift5-error {{immutable value 'self.s' may only be initialized once}}
   init(_ s: SendableData) {}
 
   func doSomething() {}
@@ -50,9 +58,15 @@ func unspecifiedFunctionTest2() async {
 
 nonisolated func nonisolatedFunctionTest() async {
   let k = await StructContainingKlass()
-  await unspecifiedAsync(k.k) // expected-error {{non-sendable type 'Klass' of property 'k' cannot exit main actor-isolated context}}
-  await nonisolatedAsync(k.k) // expected-error {{non-sendable type 'Klass' of property 'k' cannot exit main actor-isolated context}}
-  await mainActorAsync(k.k) // expected-error {{non-sendable type 'Klass' of property 'k' cannot exit main actor-isolated context}}
+  await unspecifiedAsync(k.k)
+  // expected-swift5-warning@-1 {{non-Sendable type 'Klass' of property 'k' cannot exit main actor-isolated context}}
+  // expected-swift6-error@-2 {{non-Sendable type 'Klass' of property 'k' cannot exit main actor-isolated context}}
+  await nonisolatedAsync(k.k)
+  // expected-swift5-warning@-1 {{non-Sendable type 'Klass' of property 'k' cannot exit main actor-isolated context}}
+  // expected-swift6-error@-2 {{non-Sendable type 'Klass' of property 'k' cannot exit main actor-isolated context}}
+  await mainActorAsync(k.k)
+  // expected-swift5-warning@-1 {{non-Sendable type 'Klass' of property 'k' cannot exit main actor-isolated context}}
+  // expected-swift6-error@-2 {{non-Sendable type 'Klass' of property 'k' cannot exit main actor-isolated context}}
 }
 
 func testTask() async {
@@ -69,3 +83,98 @@ func testTaskDetached() async {
     await k.doSomething()
   }
 }
+
+// @MainActor
+extension Int {
+  func memberOfInt() { } // expected-note 3{{calls to instance method 'memberOfInt()' from outside of its actor context are implicitly asynchronous}}
+}
+
+nonisolated func testMemberOfInt(i: Int) {
+  i.memberOfInt() // expected-swift5-warning{{call to main actor-isolated instance method 'memberOfInt()' in a synchronous nonisolated context}}
+  // expected-swift6-error@-1{{call to main actor-isolated instance method 'memberOfInt()' in a synchronous nonisolated context}}
+}
+
+protocol SendableProto: Sendable { }
+
+struct MyStruct: SendableProto { }
+
+extension MyStruct: CustomStringConvertible {
+  var description: String {
+    17.memberOfInt() // okay, on main actor
+    return "hello"
+  }
+}
+
+nonisolated struct MyOtherStruct { }
+
+extension MyOtherStruct {
+  func f() {
+    17.memberOfInt() // okay, on main actor
+  }
+}
+
+nonisolated
+extension MyOtherStruct {
+  func g() {
+    17.memberOfInt() // expected-swift5-warning{{call to main actor-isolated instance method 'memberOfInt()' in a synchronous nonisolated context}}
+  // expected-swift6-error@-1{{call to main actor-isolated instance method 'memberOfInt()' in a synchronous nonisolated context}}
+  }
+}
+
+nonisolated protocol P {
+  func g()
+}
+
+struct MyP: P {
+  func g() {
+    17.memberOfInt() // okay, on main actor
+  }
+}
+
+// Above tests for imported types
+extension ImportedStruct: @retroactive CustomStringConvertible {
+  public var description: String {
+    17.memberOfInt() // okay, on main actor
+    return "hello"
+  }
+}
+
+extension ImportedOtherStruct {
+  func f() {
+    17.memberOfInt() // okay, on main actor
+  }
+}
+
+nonisolated
+extension ImportedOtherStruct {
+  func g() {
+    17.memberOfInt() // expected-swift5-warning{{call to main actor-isolated instance method 'memberOfInt()' in a synchronous nonisolated context}}
+  // expected-swift6-error@-1{{call to main actor-isolated instance method 'memberOfInt()' in a synchronous nonisolated context}}
+  }
+}
+
+struct MyImportedP: ImportedP {
+  func g() {
+    17.memberOfInt() // okay, on main actor
+  }
+}
+
+// https://github.com/swiftlang/swift/issues/82168 -
+nonisolated protocol OtherP {
+  associatedtype AT
+  static var at: AT { get }
+}
+
+nonisolated struct KP<R: OtherP, V> {
+  init(keyPath: KeyPath<R, V>) {}
+}
+
+struct S: OtherP {
+  let p: Int
+  struct AT {
+    let kp = KP(keyPath: \S.p)
+  }
+
+  // FIXME: This should not be an error.
+  static let at = AT() // expected-swift6-error{{'S.AT' cannot be constructed because it has no accessible initializers}}
+}
diff --git a/test/Concurrency/assume_mainactor_typechecker_errors_sendablecheck.swift b/test/Concurrency/assume_mainactor_typechecker_errors_sendablecheck.swift
new file mode 100644
index 0000000000000..bb7ca77a9ee2c
--- /dev/null
+++ b/test/Concurrency/assume_mainactor_typechecker_errors_sendablecheck.swift
@@ -0,0 +1,19 @@
+// RUN: %target-swift-frontend -swift-version 5 -emit-sil -default-isolation MainActor %s -verify -verify-additional-prefix swift5-
+// RUN: %target-swift-frontend -swift-version 6 -emit-sil -default-isolation MainActor %s -verify -verify-additional-prefix swift6-
+
+// Ensure that a Sendable-conforming protocol suppresses @MainActor inference
+// for a type.
+enum CK: CodingKey {
+  case one
+
+  func f() { }
+
+  struct Nested {
+    func g() { }
+  }
+}
+
+nonisolated func testCK(x: CK, y: CK.Nested) {
+  x.f() // okay, because CK and CK.f are not @MainActor.
+  y.g()
+}
diff --git a/test/Concurrency/async_computed_property.swift b/test/Concurrency/async_computed_property.swift
index 219b85ff429a0..6199c0ea4631b 100644
--- a/test/Concurrency/async_computed_property.swift
+++ b/test/Concurrency/async_computed_property.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 func asyncFunc(_ value: String) async {}
 
diff --git a/test/Concurrency/async_conformance.swift b/test/Concurrency/async_conformance.swift
index 8a96ba40c9216..defbc45bf132b 100644
--- a/test/Concurrency/async_conformance.swift
+++ b/test/Concurrency/async_conformance.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify %s
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=targeted %s
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=complete %s
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation %s
 
 // REQUIRES: objc_interop
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 import Foundation
 
@@ -14,7 +12,7 @@ import Foundation
     func track(event: String) async // expected-note {{protocol requires function 'track(event:)' with type '(String) async -> ()'}}
 }
 class Dog: NSObject, Tracker { // expected-error {{type 'Dog' does not conform to protocol 'Tracker'}} expected-note {{add stubs for conformance}}
-    func track(event: String) {} // expected-note {{candidate is not 'async', but @objc protocol requirement is}}
+    func track(event: String) {} // expected-note {{candidate is not 'async', but '@objc' protocol requirement is}}
 }
 
 // sync objc requirement, async witness
@@ -22,7 +20,7 @@ class Dog: NSObject, Tracker { // expected-error {{type 'Dog' does not conform t
     func run(event: String) // expected-note {{protocol requires function 'run(event:)' with type '(String) -> ()'}}
 }
 class Athlete: NSObject, Runner { // expected-error {{type 'Athlete' does not conform to protocol 'Runner'}} expected-note {{add stubs for conformance}}
-    func run(event: String) async {} // expected-note {{candidate is 'async', but @objc protocol requirement is not}}
+    func run(event: String) async {} // expected-note {{candidate is 'async', but '@objc' protocol requirement is not}}
 }
 
 
diff --git a/test/Concurrency/async_initializer.swift b/test/Concurrency/async_initializer.swift
index 13e65397f8be7..a1cee574ebb2f 100644
--- a/test/Concurrency/async_initializer.swift
+++ b/test/Concurrency/async_initializer.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify %s
 // RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=targeted %s
-// RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=complete %s -verify-additional-prefix complete-and-tns-
-// RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation %s -verify-additional-prefix complete-and-tns-
+// RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=complete %s -verify-additional-prefix complete-
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 ////
 // some functions to play with
@@ -117,11 +115,11 @@ struct SomeStruct {
   @MainActor(unsafe) init(asyncMainActorUnsafe: Int) async {}
 
   // expected-warning@+2 {{'(unsafe)' global actors are deprecated; use '@preconcurrency' instead}}
-  // expected-complete-and-tns-note@+1 {{calls to initializer 'init(mainActorUnsafe:)' from outside of its actor context are implicitly asynchronous}}
+  // expected-complete-note@+1 {{calls to initializer 'init(mainActorUnsafe:)' from outside of its actor context are implicitly asynchronous}}
   @MainActor(unsafe) init(mainActorUnsafe: Int) {}
 }
 
-// expected-complete-and-tns-note @+3 {{add '@MainActor' to make global function 'globActorTest1()' part of global actor 'MainActor'}}
+// expected-complete-note @+3 {{add '@MainActor' to make global function 'globActorTest1()' part of global actor 'MainActor'}}
 // expected-note @+2 {{add '@MainActor' to make global function 'globActorTest1()' part of global actor 'MainActor'}}
 // expected-note @+1 2 {{add 'async' to function 'globActorTest1()' to make it asynchronous}}
 func globActorTest1() {
@@ -131,7 +129,7 @@ func globActorTest1() {
 
   _ = SomeStruct(asyncMainActorUnsafe: 0) // expected-error {{'async' call in a function that does not support concurrency}}
 
-  _ = SomeStruct(mainActorUnsafe: 0) // expected-complete-and-tns-warning {{call to main actor-isolated initializer 'init(mainActorUnsafe:)' in a synchronous nonisolated context}}
+  _ = SomeStruct(mainActorUnsafe: 0) // expected-complete-warning {{call to main actor-isolated initializer 'init(mainActorUnsafe:)' in a synchronous nonisolated context}}
 }
 
 func globActorTestAsyncEdition() async {
diff --git a/test/Concurrency/async_initializer_objc.swift b/test/Concurrency/async_initializer_objc.swift
index 20dbe49da04e1..097c0ef73a5a7 100644
--- a/test/Concurrency/async_initializer_objc.swift
+++ b/test/Concurrency/async_initializer_objc.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
 // REQUIRES: objc_interop
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 import Foundation
 
diff --git a/test/Concurrency/async_let_capture.swift b/test/Concurrency/async_let_capture.swift
index f82f3d94f917a..b12f954ca669f 100644
--- a/test/Concurrency/async_let_capture.swift
+++ b/test/Concurrency/async_let_capture.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple  %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple  %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple  %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple  %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 func autoclosureCapture(_: @autoclosure () async throws -> Int) async {}
 func nonescapingCapture(_: () async throws -> Int) {}
diff --git a/test/Concurrency/async_let_isolation.swift b/test/Concurrency/async_let_isolation.swift
index a5ea441d7e19a..d1932eb9f7ab2 100644
--- a/test/Concurrency/async_let_isolation.swift
+++ b/test/Concurrency/async_let_isolation.swift
@@ -5,7 +5,7 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted -verify-additional-prefix without-transferring-
 
 // Then strict-concurrency with everything.
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -verify-additional-prefix tns-
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
diff --git a/test/Concurrency/async_main_invalid_global_actor.swift b/test/Concurrency/async_main_invalid_global_actor.swift
index 9d5273b5c3a4e..1f0630ef7ff6f 100644
--- a/test/Concurrency/async_main_invalid_global_actor.swift
+++ b/test/Concurrency/async_main_invalid_global_actor.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -parse-as-library %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -parse-as-library %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -parse-as-library %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -parse-as-library %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @globalActor
 actor Kat {
diff --git a/test/Concurrency/async_main_mainactor_isolation.swift b/test/Concurrency/async_main_mainactor_isolation.swift
index fa0afc591b669..12522b14298a0 100644
--- a/test/Concurrency/async_main_mainactor_isolation.swift
+++ b/test/Concurrency/async_main_mainactor_isolation.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -parse-as-library %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -parse-as-library %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -parse-as-library %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -parse-as-library %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // This should pass without any warnings or errors
 
diff --git a/test/Concurrency/async_main_resolution.swift b/test/Concurrency/async_main_resolution.swift
index 02592a9718263..604ffeca8cebb 100644
--- a/test/Concurrency/async_main_resolution.swift
+++ b/test/Concurrency/async_main_resolution.swift
@@ -63,12 +63,12 @@ extension MainProtocol {
 #endif
 
 // CHECK-IS-SYNC-LABEL: "MyMain" interface_type="MyMain.Type"
-// CHECK-IS-SYNC: (func_decl {{.*}}implicit "$main()" interface_type="(MyMain.Type) -> () -> ()"
+// CHECK-IS-SYNC: (func_decl {{.*}}implicit range={{.*}} "$main()" interface_type="(MyMain.Type) -> () -> ()"
 // CHECK-IS-SYNC:       (declref_expr implicit type="(MyMain.Type) -> () -> ()"
 
 // CHECK-IS-ASYNC-LABEL: "MyMain" interface_type="MyMain.Type"
-// CHECK-IS-ASYNC: (func_decl {{.*}}implicit "$main()" interface_type="(MyMain.Type) -> () async -> ()"
+// CHECK-IS-ASYNC: (func_decl {{.*}}implicit range={{.*}} "$main()" interface_type="(MyMain.Type) -> () async -> ()"
 // CHECK-IS-ASYNC:       (declref_expr implicit type="(MyMain.Type) -> () async -> ()"
 
-// CHECK-IS-ERROR1: error: 'MyMain' is annotated with @main and must provide a main static function of type {{\(\) -> Void or \(\) throws -> Void|\(\) -> Void, \(\) throws -> Void, \(\) async -> Void, or \(\) async throws -> Void}}
+// CHECK-IS-ERROR1: error: 'MyMain' is annotated with '@main' and must provide a main static function of type {{\(\) -> Void or \(\) throws -> Void|\(\) -> Void, \(\) throws -> Void, \(\) async -> Void, or \(\) async throws -> Void}}
 // CHECK-IS-ERROR2: error: ambiguous use of 'main'
diff --git a/test/Concurrency/async_sequence_existential.swift b/test/Concurrency/async_sequence_existential.swift
index 9390cca800727..95d032c36a790 100644
--- a/test/Concurrency/async_sequence_existential.swift
+++ b/test/Concurrency/async_sequence_existential.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -dump-ast 2>&1 | %FileCheck %s
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -primary-file %s -dump-ast -o %t.ast.txt
+// RUN: %FileCheck %s < %t.ast.txt
 
 // REQUIRES: concurrency
 
@@ -9,7 +10,8 @@ extension Error {
 }
 
 func test(seq: any AsyncSequence) async {
-  // CHECK: "error" interface_type="any Error"
+  // CHECK-LABEL: (catch_stmts
+  // CHECK:         (var_decl {{.*}} "error" interface_type="any Error"
   do {
     for try await _ in seq { }
   } catch {
diff --git a/test/Concurrency/async_task_base_priority.swift b/test/Concurrency/async_task_base_priority.swift
index 763ef3ad14a14..6e5e722a915a1 100644
--- a/test/Concurrency/async_task_base_priority.swift
+++ b/test/Concurrency/async_task_base_priority.swift
@@ -1,4 +1,4 @@
-// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library )
+// RUN: %target-run-simple-swift( %import-libdispatch -parse-as-library )
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
@@ -40,6 +40,7 @@ func print(_ s: String = "") {
   fputs("\(s)\n", stderr)
 }
 
+@available(SwiftStdlib 5.9, *)
 func expectedBasePri(priority: TaskPriority) -> TaskPriority {
   let basePri = Task.basePriority!
 
@@ -48,6 +49,7 @@ func expectedBasePri(priority: TaskPriority) -> TaskPriority {
   return basePri
 }
 
+@available(SwiftStdlib 5.9, *)
 func expectedCurrentPri(priority: TaskPriority) -> TaskPriority {
   let curPri = Task.currentPriority
   print("Testing curPri matching expected pri - \(curPri) == \(priority)")
@@ -55,25 +57,25 @@ func expectedCurrentPri(priority: TaskPriority) -> TaskPriority {
   return curPri
 }
 
+@available(SwiftStdlib 5.9, *)
 func testNestedTaskPriority(basePri: TaskPriority, curPri: TaskPriority) async {
-    let _ = expectedBasePri(priority: basePri)
-    let _ = expectedCurrentPri(priority: curPri)
+  let _ = expectedBasePri(priority: basePri)
+  let _ = expectedCurrentPri(priority: curPri)
 }
 
 @main struct Main {
   static func main() async {
-
-    let top_level = detach { /* To detach from main actor when running work */
+    let top_level = Task.detached { /* To detach from main actor when running work */
 
       let tests = TestSuite("Task base priority")
-      if #available(SwiftStdlib 5.1, *) {
+      if #available(SwiftStdlib 5.9, *) {
 
         tests.test("Structured concurrency base priority propagation") {
-          let task = Task(priority: .background) {
-            await loopUntil(priority: .default)
+          let task = Task.detached(priority: .background) {
+            await loopUntil(priority: .medium)
 
             let basePri = expectedBasePri(priority: .background)
-            let curPri = expectedCurrentPri(priority: .default)
+            let curPri = expectedCurrentPri(priority: .medium)
 
             // Structured concurrency via async let, escalated priority of
             // parent should propagate
@@ -111,11 +113,11 @@ func testNestedTaskPriority(basePri: TaskPriority, curPri: TaskPriority) async {
         }
 
         tests.test("Unstructured base priority propagation") {
-          let task = Task(priority : .background) {
-            await loopUntil(priority: .default)
+          let task = Task.detached(priority: .background) {
+            await loopUntil(priority: .medium)
 
             let basePri = expectedBasePri(priority: .background)
-            let _ = expectedCurrentPri(priority: .default)
+            let _ = expectedCurrentPri(priority: .medium)
 
             let group = DispatchGroup()
 
@@ -124,7 +126,6 @@ func testNestedTaskPriority(basePri: TaskPriority, curPri: TaskPriority) async {
             let _ = Task {
               let _ = await testNestedTaskPriority(basePri: basePri, curPri: basePri)
               group.leave()
-              return
             }
 
             // Wait for unstructured task to finish running, don't await it
diff --git a/test/Concurrency/async_task_escalate_priority.swift b/test/Concurrency/async_task_escalate_priority.swift
index d017d01cef112..4eae25c027780 100644
--- a/test/Concurrency/async_task_escalate_priority.swift
+++ b/test/Concurrency/async_task_escalate_priority.swift
@@ -19,9 +19,6 @@
 // UNSUPPORTED: DARWIN_SIMULATOR=ios
 // UNSUPPORTED: DARWIN_SIMULATOR=tvos
 
-// rdar://107390341 - Because task escalation tests seem disabled on this platform
-// UNSUPPORTED: CPU=arm64e
-
 import Darwin
 @preconcurrency import Dispatch
 
diff --git a/test/Concurrency/async_task_groups.swift b/test/Concurrency/async_task_groups.swift
index fcd33b29c62a9..cca22c125c268 100644
--- a/test/Concurrency/async_task_groups.swift
+++ b/test/Concurrency/async_task_groups.swift
@@ -1,6 +1,6 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -verify-additional-prefix tns-
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
diff --git a/test/Concurrency/async_task_groups_and_actors.swift b/test/Concurrency/async_task_groups_and_actors.swift
index ae07d2c3e7647..0407ce96f5ed1 100644
--- a/test/Concurrency/async_task_groups_and_actors.swift
+++ b/test/Concurrency/async_task_groups_and_actors.swift
@@ -1,8 +1,7 @@
-// RUN: %target-swift-frontend  -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
+// RUN: %target-swift-frontend  -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
 
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @MainActor
 class MyActor {
diff --git a/test/Concurrency/async_task_groups_and_type_inference.swift b/test/Concurrency/async_task_groups_and_type_inference.swift
index d0cf74275ab22..653202788f245 100644
--- a/test/Concurrency/async_task_groups_and_type_inference.swift
+++ b/test/Concurrency/async_task_groups_and_type_inference.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=complete
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
diff --git a/test/Concurrency/async_task_groups_as_sequence.swift b/test/Concurrency/async_task_groups_as_sequence.swift
index e317699346ad2..0c86659a72b90 100644
--- a/test/Concurrency/async_task_groups_as_sequence.swift
+++ b/test/Concurrency/async_task_groups_as_sequence.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @available(SwiftStdlib 5.1, *)
 @rethrows
diff --git a/test/Concurrency/async_task_locals_basic_warnings.swift b/test/Concurrency/async_task_locals_basic_warnings.swift
index 7e751d038629d..9617b34ad6f01 100644
--- a/test/Concurrency/async_task_locals_basic_warnings.swift
+++ b/test/Concurrency/async_task_locals_basic_warnings.swift
@@ -2,11 +2,9 @@
 // RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -emit-module -emit-module-path %t/OtherActors.swiftmodule -module-name OtherActors %S/Inputs/OtherActors.swift -target %target-swift-5.1-abi-triple
 
 // RUN: %target-swift-frontend -I %t -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify
-// RUN: %target-swift-frontend -I %t -plugin-path %swift-plugin-dir -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -enable-upcoming-feature RegionBasedIsolation
 // RUN: %target-swift-frontend -I %t -plugin-path %swift-plugin-dir -disable-availability-checking -swift-version 6 -parse-as-library %s -emit-sil -o /dev/null -verify
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 actor Test {
 
diff --git a/test/Concurrency/async_task_locals_basic_warnings_bug_isolation.swift b/test/Concurrency/async_task_locals_basic_warnings_bug_isolation.swift
index 65d56725fb657..c7cb5f95ee9db 100644
--- a/test/Concurrency/async_task_locals_basic_warnings_bug_isolation.swift
+++ b/test/Concurrency/async_task_locals_basic_warnings_bug_isolation.swift
@@ -13,9 +13,6 @@ actor Test {
   func withTaskLocal(isolation: isolated (any Actor)? = #isolation,
                      _ body: (consuming NonSendableValue, isolated (any Actor)?) -> Void) async {
     Self.$local.withValue(12) {
-      // Unexpected errors here:
-      //  error: unexpected warning produced: sending 'body' risks causing data races; this is an error in the Swift 6 language mode
-      //  error: unexpected note produced: actor-isolated 'body' is captured by a actor-isolated closure. actor-isolated uses in closure may race against later nonisolated uses
       body(NonSendableValue(), isolation)
     }
   }
diff --git a/test/Concurrency/async_task_priority.swift b/test/Concurrency/async_task_priority.swift
index b72e272374ff7..7d3ed8765bdec 100644
--- a/test/Concurrency/async_task_priority.swift
+++ b/test/Concurrency/async_task_priority.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-build-swift %s -Xfrontend -disable-availability-checking -parse-as-library -o %t/async_task_priority
+// RUN: %target-build-swift %s -parse-as-library -o %t/async_task_priority
 // RUN: %target-codesign %t/async_task_priority
 // RUN: %target-run %t/async_task_priority
 
@@ -26,6 +26,7 @@ import Darwin
 @preconcurrency import Dispatch
 import StdlibUnittest
 
+@available(SwiftStdlib 5.9, *)
 func loopUntil(priority: TaskPriority) async {
   var currentPriority = Task.currentPriority
   while (currentPriority != priority) {
@@ -39,6 +40,7 @@ func print(_ s: String = "") {
   fputs("\(s)\n", stderr)
 }
 
+@available(SwiftStdlib 5.9, *)
 func expectedBasePri(priority: TaskPriority) -> TaskPriority {
   let basePri = Task.basePriority!
   print("Testing basePri matching expected pri - \(basePri) == \(priority)")
@@ -54,6 +56,7 @@ func expectedBasePri(priority: TaskPriority) -> TaskPriority {
   return basePri
 }
 
+@available(SwiftStdlib 5.9, *)
 func expectedEscalatedPri(priority: TaskPriority) -> TaskPriority {
   let curPri = Task.currentPriority
   print("Testing escalated matching expected pri - \(curPri) == \(priority)")
@@ -62,16 +65,19 @@ func expectedEscalatedPri(priority: TaskPriority) -> TaskPriority {
   return curPri
 }
 
+@available(SwiftStdlib 5.9, *)
 func testNestedTaskPriority(basePri: TaskPriority, curPri: TaskPriority) async {
     let _ = expectedBasePri(priority: basePri)
     let _ = expectedEscalatedPri(priority: curPri)
 }
 
+@available(SwiftStdlib 5.9, *)
 func childTaskWaitingForEscalation(sem: DispatchSemaphore, basePri: TaskPriority, curPri : TaskPriority) async {
     sem.wait() /* Wait to be escalated */
     let _ = await testNestedTaskPriority(basePri: basePri, curPri: curPri)
 }
 
+@available(SwiftStdlib 5.9, *)
 actor Test {
   private var value = 0
   init() { }
@@ -88,8 +94,7 @@ actor Test {
     semToWait.wait();
 
     sleep(1)
-    // TODO: insert a test to verify that thread priority has actually escalated
-    // to match priExpected
+    // FIXME: insert a test to verify that thread priority has actually escalated to match priExpected
     return increment()
   }
 
@@ -98,17 +103,16 @@ actor Test {
 
 @main struct Main {
   static func main() async {
-
-    let top_level = detach { /* To detach from main actor when running work */
+    let top_level = Task.detached { /* To detach from main actor when running work */
 
       let tests = TestSuite("Task Priority manipulations")
-      if #available(SwiftStdlib 5.1, *) {
+      if #available(SwiftStdlib 5.9, *) {
 
         tests.test("Basic escalation test when task is running") {
             let parentPri = Task.currentPriority
 
             let sem = DispatchSemaphore(value: 0)
-            let task = Task(priority: .background) {
+            let task = Task.detached(priority: .background) {
                 let _ = expectedBasePri(priority: .background)
 
                 // Wait until task is running before asking to be escalated
@@ -136,15 +140,15 @@ actor Test {
 
         tests.test("Structured concurrency priority propagation") {
           let task = Task(priority: .background) {
-            await loopUntil(priority: .default)
+            await loopUntil(priority: .medium)
 
             let basePri = expectedBasePri(priority: .background)
-            let curPri = expectedEscalatedPri(priority: .default)
+            let curPri = expectedEscalatedPri(priority: .medium)
 
             // Structured concurrency via async let, escalated priority of
             // parent should propagate
             print("Testing propagation for async let structured concurrency child")
-            async let child = testNestedTaskPriority(basePri: basePri, curPri: curPri)
+            async let child: () = testNestedTaskPriority(basePri: basePri, curPri: curPri)
             await child
 
             let dispatchGroup = DispatchGroup()
@@ -177,11 +181,11 @@ actor Test {
         }
 
         tests.test("Unstructured tasks priority propagation") {
-          let task = Task(priority : .background) {
-            await loopUntil(priority: .default)
+          let task = Task.detached(priority: .background) {
+            await loopUntil(priority: .medium)
 
             let basePri = expectedBasePri(priority: .background)
-            let _ = expectedEscalatedPri(priority: .default)
+            let _ = expectedEscalatedPri(priority: .medium)
 
             let group = DispatchGroup()
 
@@ -190,7 +194,6 @@ actor Test {
             let _ = Task {
               let _ = await testNestedTaskPriority(basePri: basePri, curPri: basePri)
               group.leave()
-              return
             }
 
             // Wait for unstructured task to finish running, don't await it
@@ -201,72 +204,70 @@ actor Test {
           await task.value // Escalate task BG->DEF
         }
 
-        tests.test("Task escalation propagation to SC children") {
-            // Create a task tree and then escalate the parent
-            let parentPri = Task.currentPriority
-            let basePri : TaskPriority = .background
-
-            let sem = DispatchSemaphore(value: 0)
-            let sem2 = DispatchSemaphore(value : 0)
+        tests.test("Task escalation propagation to structured concurrency child tasks") {
+          // Create a task tree and then escalate the parent
+          let parentPri = Task.currentPriority
+          let basePri : TaskPriority = .background
 
-            let task = Task(priority: basePri) {
+          let sem = DispatchSemaphore(value: 0)
+          let sem2 = DispatchSemaphore(value: 0)
 
-                async let child = childTaskWaitingForEscalation(sem: sem2, basePri: basePri, curPri: parentPri)
+          let task = Task.detached(priority: basePri) {
+            async let child = childTaskWaitingForEscalation(sem: sem2, basePri: basePri, curPri: parentPri)
 
-                await withTaskGroup(of: Void.self, returning: Void.self) { group in
-                    group.addTask {
-                        let _ = await childTaskWaitingForEscalation(sem: sem2, basePri: basePri, curPri: parentPri)
-                    }
-                    group.addTask(priority: .utility) {
-                        let _ = await childTaskWaitingForEscalation(sem: sem2, basePri: .utility, curPri: parentPri)
-                    }
+            await withTaskGroup { group in
+              group.addTask {
+                let _ = await childTaskWaitingForEscalation(sem: sem2, basePri: basePri, curPri: parentPri)
+              }
+              group.addTask(priority: .utility) {
+                let _ = await childTaskWaitingForEscalation(sem: sem2, basePri: .utility, curPri: parentPri)
+              }
 
-                    sem.signal() // Ask for escalation after creating full task tree
-                    sleep(1)
+              sem.signal() // Ask for escalation after creating full task tree
+              sleep(1)
 
-                    let _ = expectedBasePri(priority: basePri)
-                    let _ = expectedEscalatedPri(priority: parentPri)
+              let _ = expectedBasePri(priority: basePri)
+              let _ = expectedEscalatedPri(priority: parentPri)
 
-                    sem2.signal() // Ask async let child to evaluate
-                    sem2.signal() // Ask task group child 1 to evaluate
-                    sem2.signal() // Ask task group child 2 to evaluate
-                }
+              sem2.signal() // Ask async let child to evaluate
+              sem2.signal() // Ask task group child 1 to evaluate
+              sem2.signal() // Ask task group child 2 to evaluate
             }
+          }
 
-            // Wait until children are created and then ask for escalation of
-            // top level
-            sem.wait()
-            await task.value
+          // Wait until children are created and then ask for escalation of top level
+          sem.wait()
+          await task.value
         }
 
         tests.test("Simple task escalation to a future") {
-            let task1Pri: TaskPriority = .background
-            let task2Pri: TaskPriority = .utility
-            let parentPri: TaskPriority =  Task.currentPriority
-            print("Top level task current priority = \(parentPri)")
+          let task1Pri: TaskPriority = .background
+          let task2Pri: TaskPriority = .utility
+          let parentPri: TaskPriority =  Task.currentPriority
+          print("Top level task current priority = \(parentPri)")
 
-            //  After task2 has suspended waiting for task1, escalating task2
-            //  should cause task1 to escalate
+          // After task2 has suspended waiting for task1,
+          // escalating task2 should cause task1 to escalate
 
-            let task1 = Task(priority: task1Pri) {
-                // Wait until task2 has blocked on task1 and escalated it
-                sleep(1)
-                expectedEscalatedPri(priority: task2Pri)
+          let task1 = Task.detached(priority: task1Pri) {
+            // Wait until task2 has blocked on task1 and escalated it
+            sleep(1)
+            _ = expectedEscalatedPri(priority: task2Pri)
 
-                // Wait until task2 itself has been escalated
-                sleep(5)
-                expectedEscalatedPri(priority: parentPri)
-            }
+            // Wait until task2 itself has been escalated
+            sleep(5)
+            _ = expectedEscalatedPri(priority: parentPri)
+          }
 
-            let task2 = Task(priority: task2Pri) {
-                await task1.value
-            }
+          let task2 = Task.detached(priority: task2Pri) {
+            await task1.value
+          }
 
-            // Wait for task2 and task1 to run and for task2 to now block on
-            // task1
-            sleep(3)
+          // Wait for task2 and task1 to run and for task2 to now block on
+          // task1
+          sleep(3)
 
-            await task2.value
+          await task2.value
         }
 
         tests.test("Simple task escalation to a future 2") {
@@ -283,11 +284,11 @@ actor Test {
 
             sleep(1) // Wait for task1 to start running
 
-            let task2 = Task(priority: task2Pri) {
-                func childTask() async {
-                    await task1.value
-                }
-                async let child = childTask()
+            let task2 = Task.detached(priority: task2Pri) {
+              @Sendable func childTask() async {
+                await task1.value
+              }
+              async let child = childTask()
             }
 
             sleep(1) // Wait for task2 to start running
@@ -303,15 +304,15 @@ actor Test {
           let sem2 = DispatchSemaphore(value: 0)
           let testActor = Test()
 
-          let task1 = Task(priority: task1Pri) {
-            expectedBasePri(priority: task1Pri);
+          let task1 = Task.detached(priority: task1Pri) {
+            _ = expectedBasePri(priority: task1Pri)
             await testActor.blockActorThenIncrement(semToSignal: sem1, semToWait: sem2, priExpected: parentPri);
           }
 
           sem1.wait() // Wait until task1 is on the actor
 
           let task2 = Task(priority: task2Pri) {
-            expectedBasePri(priority: task2Pri);
+            _ = expectedBasePri(priority: task2Pri)
             await testActor.increment()
           }
 
diff --git a/test/Concurrency/async_tasks.swift b/test/Concurrency/async_tasks.swift
index f470f937b3577..a3ef943c02c6d 100644
--- a/test/Concurrency/async_tasks.swift
+++ b/test/Concurrency/async_tasks.swift
@@ -1,6 +1,6 @@
 // RUN: %target-swift-frontend -strict-concurrency=targeted -target %target-swift-5.1-abi-triple %s -o /dev/null -verify -emit-sil  -DALLOW_TYPECHECKER_ERRORS -verify-additional-prefix typechecker-
 // RUN: %target-swift-frontend -strict-concurrency=complete -target %target-swift-5.1-abi-triple %s -o /dev/null -verify -emit-sil -DALLOW_TYPECHECKER_ERRORS -verify-additional-prefix typechecker-
-// RUN: %target-swift-frontend -strict-concurrency=complete -target %target-swift-5.1-abi-triple %s -o /dev/null -verify -emit-sil -verify-additional-prefix tns-
+// RUN: %target-swift-frontend -strict-concurrency=complete -target %target-swift-5.1-abi-triple %s -o /dev/null -verify -emit-sil -verify-additional-prefix complete-
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
@@ -140,9 +140,9 @@ func test_detached_throwing() async -> String {
 
 // ==== Detached Tasks with inout Params---------------------------------------
 @available(SwiftStdlib 5.1, *)
-func printOrderNumber(n: inout Int) async { // expected-tns-note {{parameter 'n' is declared 'inout'}}
-  Task.detached { // expected-tns-error {{escaping closure captures 'inout' parameter 'n'}}
-      n+=1 // expected-tns-note {{captured here}}
-      print(n) // expected-tns-note {{captured here}}
+func printOrderNumber(n: inout Int) async { // expected-complete-note {{parameter 'n' is declared 'inout'}}
+  Task.detached { // expected-complete-error {{escaping closure captures 'inout' parameter 'n'}}
+      n+=1 // expected-complete-note {{captured here}}
+      print(n) // expected-complete-note {{captured here}}
   }
 }
diff --git a/test/Concurrency/async_throwing.swift b/test/Concurrency/async_throwing.swift
index 9a25f48658153..becdcab5946de 100644
--- a/test/Concurrency/async_throwing.swift
+++ b/test/Concurrency/async_throwing.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // These tests cover various interactions with async functions that are
 // either throws or rethrows.
diff --git a/test/Concurrency/attr_discardableResult_async_await.swift b/test/Concurrency/attr_discardableResult_async_await.swift
index d8f3e7f822cc6..9b8770537ffb3 100644
--- a/test/Concurrency/attr_discardableResult_async_await.swift
+++ b/test/Concurrency/attr_discardableResult_async_await.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // https://github.com/apple/swift/issues/60276
 
@@ -14,3 +12,23 @@ func mainActorAsyncDiscardable() async -> Int { 0 }
 func consumesMainActorAsyncDiscardable() async {
   await mainActorAsyncDiscardable() // ok
 }
+
+// https://github.com/swiftlang/swift/issues/83463
+
+@MainActor
+@discardableResult
+func returnsDiscardableFunc() -> () -> Void { return {} }
+
+@MainActor
+func testDiscardsSyncFuncWithImplicitSendableConversion() {
+    returnsDiscardableFunc()
+}
+
+@MainActor
+@discardableResult
+func mainActorAsyncReturnsDiscardableFunc() async -> () -> Void { return {} }
+
+@MainActor
+func discardsAsyncFuncWithImplicitSendableConversion() async {
+  await mainActorAsyncReturnsDiscardableFunc()
+}
diff --git a/test/Concurrency/attr_execution/adoption_mode.swift b/test/Concurrency/attr_execution/adoption_mode.swift
deleted file mode 100644
index f8cdcad4c3978..0000000000000
--- a/test/Concurrency/attr_execution/adoption_mode.swift
+++ /dev/null
@@ -1,275 +0,0 @@
-// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple -swift-version 5 -enable-experimental-feature ExecutionAttribute -enable-experimental-feature AsyncCallerExecution:adoption
-// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple -swift-version 6 -enable-experimental-feature ExecutionAttribute -enable-experimental-feature AsyncCallerExecution:adoption
-
-// REQUIRES: swift_feature_ExecutionAttribute
-// REQUIRES: swift_feature_AsyncCallerExecution
-
-struct G<T> {
-  init(_: T) {}
-}
-
-@execution(concurrent) func globalAsyncF() async {}
-
-// MARK: Functions
-do {
-  func syncF() {}
-  @execution(concurrent) func executionConcurrentAsyncF() async {}
-  @execution(caller) func executionCallerAsyncF() async {}
-  @MainActor func mainActorAsyncF() async {}
-  func isolatedParamAsyncF(
-    isolation: isolated (any Actor)? = #isolation
-  ) async {}
-
-  // expected-warning@+1:20 {{feature 'AsyncCallerExecution' will cause nonisolated async local function 'asyncF' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{3-3=@execution(concurrent) }}{{none}}
-  nonisolated func asyncF() async {}
-
-  struct S {
-    init(sync: ()) {}
-    @execution(concurrent) init(executionAsync: ()) async {}
-    @MainActor init(mainActorAsync: ()) async {}
-    // expected-warning@+1:5 {{feature 'AsyncCallerExecution' will cause nonisolated async initializer 'init' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{5-5=@execution(concurrent) }}{{none}}
-    init(async: ()) async {}
-
-    func syncF() {}
-    @execution(concurrent) func executionAsyncF() async {}
-    @MainActor func mainActorAsyncF() async {}
-    // expected-warning@+2:17 {{feature 'AsyncCallerExecution' will cause nonisolated async instance method 'asyncF' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{-1:5-5=@execution(concurrent) }}{{none}}
-    nonisolated
-    public func asyncF() async {}
-  }
-
-  protocol P {
-    init(sync: ())
-    @execution(concurrent) init(executionAsync: ()) async
-    @MainActor init(mainActorAsync: ()) async
-    // expected-warning@+1:5 {{feature 'AsyncCallerExecution' will cause nonisolated async initializer 'init' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{5-5=@execution(concurrent) }}{{none}}
-    init(async: ()) async
-
-    func syncF()
-    @execution(concurrent) func executionAsyncF() async
-    @MainActor func mainActorAsyncF() async
-    // expected-warning@+1:10 {{feature 'AsyncCallerExecution' will cause nonisolated async instance method 'asyncF' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{5-5=@execution(concurrent) }}{{none}}
-    func asyncF() async
-  }
-}
-protocol Functions {}
-extension Functions {
-  init(sync: ()) {}
-  @execution(concurrent) init(executionAsync: ()) async {}
-  @MainActor init(mainActorAsync: ()) async {}
-  // expected-warning@+1:3 {{feature 'AsyncCallerExecution' will cause nonisolated async initializer 'init' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{3-3=@execution(concurrent) }}{{none}}
-  init(async: ()) async {}
-
-  func syncF() {}
-  @execution(concurrent) func executionAsyncF() async {}
-  @MainActor func mainActorAsyncF() async {}
-  // expected-warning@+1:8 {{feature 'AsyncCallerExecution' will cause nonisolated async instance method 'asyncF' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{3-3=@execution(concurrent) }}{{none}}
-  func asyncF() async {}
-}
-
-// MARK: Storage
-do {
-  struct S {
-    var storedVar: Int
-    let storedLet: Int
-
-    var syncS: Int { get {} set {} }
-    subscript(syncS _: Int) -> Int { get {} }
-
-    @execution(concurrent) var executionAsyncS: Int { get async {} }
-    @execution(concurrent) subscript(executionAsyncS _: Int) -> Int { get async {} }
-
-    @MainActor var mainActorAsyncS: Int { get async {} }
-    @MainActor subscript(mainActorAsyncS _: Int) -> Int { get async {} }
-
-    // expected-warning@+2:7 {{feature 'AsyncCallerExecution' will cause nonisolated async getter for property 'asyncS' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{-1:5-5=@execution(concurrent) }}{{none}}
-    var asyncS: Int {
-      get async {}
-    }
-    // expected-warning@+2:7 {{feature 'AsyncCallerExecution' will cause nonisolated async getter for subscript 'subscript' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{-1:5-5=@execution(concurrent) }}{{none}}
-    subscript(asyncS _: Int) -> Int {
-      get async throws {}
-    }
-  }
-
-  protocol P {
-    var syncS: Int { get }
-    subscript(syncS _: Int) -> Int { get }
-
-    @execution(concurrent) var executionAsyncS: Int { get async }
-    @execution(concurrent) subscript(executionAsyncS _: Int) -> Int { get async }
-
-    @MainActor var mainActorAsyncS: Int { get async }
-    @MainActor subscript(mainActorAsyncS _: Int) -> Int { get async }
-
-    // expected-warning@+1:23 {{feature 'AsyncCallerExecution' will cause nonisolated async getter for property 'asyncS' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{5-5=@execution(concurrent) }}{{none}}
-    var asyncS: Int { get async }
-    // expected-warning@+1:39 {{feature 'AsyncCallerExecution' will cause nonisolated async getter for subscript 'subscript' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{5-5=@execution(concurrent) }}{{none}}
-    subscript(asyncS _: Int) -> Int { get async }
-  }
-}
-protocol Storage {}
-extension Storage {
-  var syncS: Int { get {} set {} }
-  subscript(syncS _: Int) -> Int { get {} }
-
-  @execution(concurrent) var executionAsyncS: Int { get async {} }
-  @execution(concurrent) subscript(executionAsyncS _: Int) -> Int { get async {} }
-
-  @MainActor var mainActorAsyncS: Int { get async {} }
-  @MainActor subscript(mainActorAsyncS _: Int) -> Int { get async {} }
-
-  // expected-warning@+2:5 {{feature 'AsyncCallerExecution' will cause nonisolated async getter for property 'asyncS' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{-1:3-3=@execution(concurrent) }}{{none}}
-  var asyncS: Int {
-    get async {}
-  }
-  // expected-warning@+2:5 {{feature 'AsyncCallerExecution' will cause nonisolated async getter for subscript 'subscript' to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{-1:3-3=@execution(concurrent) }}{{none}}
-  subscript(asyncS _: Int) -> Int {
-    get async throws {}
-  }
-}
-
-
-// MARK: Parameters
-do {
-  enum E {
-    case esac(
-      sync: () -> Void,
-      executionAsync: @execution(concurrent) () async -> Void,
-      mainActorAsync: @MainActor () async -> Void,
-      // expected-warning@+1:14 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{14-14=@execution(concurrent) }}{{none}}
-      async: () async -> Void,
-      // expected-warning@+1:26 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{26-26=@execution(concurrent) }}{{none}}
-      structuralAsync: G<() async -> Void>
-    )
-  }
-
-  struct S {
-    subscript(
-      sync: () -> Void,
-      executionAsync: @execution(concurrent) () async -> Void,
-      mainActorAsync: @MainActor () async -> Void,
-      // expected-warning@+1:14 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{14-14=@execution(concurrent) }}{{none}}
-      async: () async -> Void,
-      // expected-warning@+1:26 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{26-26=@execution(concurrent) }}{{none}}
-      structuralAsync: G<() async -> Void>
-    ) -> Int {
-      0
-    }
-  }
-
-  func foo(
-    sync: () -> Void,
-    executionAsync: @execution(concurrent) () async -> Void,
-    mainActorAsync: @MainActor () async -> Void,
-    // expected-warning@+1:12 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{12-12=@execution(concurrent) }}{{none}}
-    async: () async -> Void,
-    // expected-warning@+1:24 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{24-24=@execution(concurrent) }}{{none}}
-    structuralAsync: G<() async -> Void>
-  ) {}
-
-  let _ = { (
-    sync: () -> Void,
-    executionAsync: @execution(concurrent) () async -> Void,
-    mainActorAsync: @MainActor () async -> Void,
-    // expected-warning@+1:12 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{12-12=@execution(concurrent) }}{{none}}
-    async: () async -> Void,
-    // expected-warning@+1:24 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{24-24=@execution(concurrent) }}{{none}}
-    structuralAsync: G<() async -> Void>
-  ) in
-  }
-}
-
-// MARK: Generic constraints
-do {
-  struct G<T> {
-    struct Sync where T == () -> Void {}
-    struct ExecutionAsync where T == @execution(concurrent) () async -> Void {}
-    struct MainActorAsync where T == @MainActor () async -> Void {}
-    // expected-warning@+1:29 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{29-29=@execution(concurrent) }}{{none}}
-    struct Async where T == () async -> Void {}
-    // expected-warning@+1:41 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{41-41=@execution(concurrent) }}{{none}}
-    struct StructuralAsync where T == G<() async -> Void> {}
-  }
-}
-
-// MARK: Variables
-do {
-  let _: () -> Void
-  let _: @execution(concurrent) () async -> Void
-  let _: @MainActor () async -> Void
-  // expected-warning@+1:10 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{10-10=@execution(concurrent) }}{{none}}
-  let _: () async -> Void
-  // expected-warning@+1:12 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{12-12=@execution(concurrent) }}{{none}}
-  let _: G<() async -> Void>
-}
-
-// MARK: Casts
-do {
-  let anything: Any
-
-  let _ = anything as? () -> Void
-  let _ = anything as? @execution(concurrent) () async -> Void
-  let _ = anything as? @MainActor () async -> Void
-  // expected-warning@+1:24 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{24-24=@execution(concurrent) }}{{none}}
-  let _ = anything as? () async -> Void
-  // expected-warning@+1:26 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{26-26=@execution(concurrent) }}{{none}}
-  let _ = anything as? G<() async -> Void>
-}
-
-// MARK: Closures
-do {
-  nonisolated
-  func nonisolatedF() {
-    let _ = { () -> Void in }
-
-    let _ = { @execution(concurrent) () async -> Void in }
-    let _ = { @MainActor () async -> Void in }
-
-    // expected-warning@+1:13 {{feature 'AsyncCallerExecution' will cause nonisolated async closure to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{15-15=@execution(concurrent) }}{{none}}
-    let _ = { () async -> Void in }
-
-    func takesInts(_: Int...) {}
-
-    // expected-warning@+1:13 {{feature 'AsyncCallerExecution' will cause nonisolated async closure to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{14-14= @execution(concurrent) in }}{{none}}
-    let _ = {await globalAsyncF()}
-    // expected-warning@+1:13 {{feature 'AsyncCallerExecution' will cause nonisolated async closure to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{14-14= @execution(concurrent) in }}{{none}}
-    let _ = {
-      await globalAsyncF()
-    }
-    // expected-warning@+1:13 {{feature 'AsyncCallerExecution' will cause nonisolated async closure to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{14-14= @execution(concurrent) in }}{{none}}
-    let _ = {
-      await globalAsyncF()
-      takesInts($0, $1, $2)
-    }
-    // expected-warning@+1:13 {{feature 'AsyncCallerExecution' will cause nonisolated async closure to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{25-25=@execution(concurrent) }}{{none}}
-    let _ = { @Sendable in
-      await globalAsyncF()
-    }
-    // expected-warning@+2:18 {{feature 'AsyncCallerExecution' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{18-18=@execution(concurrent) }}{{none}}
-    // expected-warning@+1:45 {{feature 'AsyncCallerExecution' will cause nonisolated async closure to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{47-47=@execution(concurrent) }}{{none}}
-    var closure: (Int, Int) async -> Void = { a, b in
-      await globalAsyncF()
-    }
-    // expected-warning@+1:15 {{feature 'AsyncCallerExecution' will cause nonisolated async closure to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{+1:7-7=@execution(concurrent) }}{{none}}
-    closure = {
-      a, b async in
-      await globalAsyncF()
-    }
-    // expected-warning@+1:15 {{feature 'AsyncCallerExecution' will cause nonisolated async closure to run on the caller's actor; use @execution(concurrent) to preserve behavior}}{{17-17=@execution(concurrent) }}{{none}}
-    closure = { (a, b) in
-      await globalAsyncF()
-    }
-
-    let _ = closure
-  }
-
-  @MainActor
-  func mainActorF() {
-    let _ = { () async -> Void in }
-    let _ = {
-      await globalAsyncF()
-    }
-  }
-}
-
diff --git a/test/Concurrency/attr_execution/attr_execution.swift b/test/Concurrency/attr_execution/attr_execution.swift
index 23700de37ed86..be472c673ebfb 100644
--- a/test/Concurrency/attr_execution/attr_execution.swift
+++ b/test/Concurrency/attr_execution/attr_execution.swift
@@ -1,17 +1,123 @@
-// RUN: %target-swift-emit-silgen -enable-experimental-feature ExecutionAttribute -enable-experimental-feature AsyncCallerExecution %s | %FileCheck %s
+// RUN: %target-swift-emit-silgen -enable-upcoming-feature NonisolatedNonsendingByDefault %s | %FileCheck %s
 
-// REQUIRES: swift_feature_ExecutionAttribute
-// REQUIRES: swift_feature_AsyncCallerExecution
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 
 // CHECK-LABEL: // concurrentTest()
 // CHECK: // Isolation: nonisolated
 // CHECK: sil hidden [ossa] @$s14attr_execution14concurrentTestyyYaF : $@convention(thin) @async () -> () {
-@execution(concurrent)
+@concurrent
 func concurrentTest() async {}
 
 // CHECK-LABEL: // callerTest()
 // CHECK: // Isolation: caller_isolation_inheriting
 // CHECK: sil hidden [ossa] @$s14attr_execution10callerTestyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
-@execution(caller)
+nonisolated(nonsending)
 func callerTest() async {}
+
+struct Test {
+  // CHECK-LABEL: // closure #1 in variable initialization expression of Test.x
+  // CHECK: // Isolation: caller_isolation_inheriting
+  // CHECK: sil private [ossa] @$s14attr_execution4TestV1xyyYaYCcvpfiyyYaYCcfU_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+  var x: () async -> Void = {}
+
+  // CHECK-LABEL: // Test.test()
+  // CHECK: // Isolation: caller_isolation_inheriting
+  // CHECK: sil hidden [ossa] @$s14attr_execution4TestV4testyyYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed Test) -> ()
+  // CHECK: bb0([[ISOLATION:%.*]] : @guaranteed $Optional<any Actor>, [[SELF:%.*]] : @guaranteed $Test)
+  // CHECK: [[X_REF:%.*]] = struct_extract %1, #Test.x
+  // CHECK: [[X_REF_COPY:%.]] = copy_value [[X_REF]]
+  // CHECK: [[BORROWED_X:%.*]] = begin_borrow [[X_REF_COPY]]
+  // CHECK: apply [[BORROWED_X]]([[ISOLATION]]) : $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+  // CHECK: } // end sil function '$s14attr_execution4TestV4testyyYaF'
+  func test() async {
+    await x()
+  }
+
+  // CHECK-LABEL: // Test.testParam(fn:)
+  // CHECK: // Isolation: caller_isolation_inheriting
+  // CHECK: sil hidden [ossa] @$s14attr_execution4TestV9testParam2fnyyyYaYCcSg_tYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed Optional<@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()>, @guaranteed Test) -> ()
+  // CHECK: bb0([[ISOLATION:%.*]] : @guaranteed $Optional<any Actor>, [[OPT_FN:%.*]] : @guaranteed $Optional<@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()>, [[SELF:%.*]] : @guaranteed $Test)
+  // CHECK: bb1([[FN:%.*]] : @owned $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ())
+  // CHECK: [[BORROWED_FN:%.*]] = begin_borrow [[FN]]
+  // CHECK: apply [[BORROWED_FN]]([[ISOLATION]]) : $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()  
+  // CHECK: } // end sil function '$s14attr_execution4TestV9testParam2fnyyyYaYCcSg_tYaF'
+  func testParam(fn: (() async -> Void)?) async {
+    await fn?()
+  }
+}
+
+// CHECK-LABEL: // testLocal()
+// CHECK: // Isolation: caller_isolation_inheriting
+// CHECK: sil hidden [ossa] @$s14attr_execution9testLocalyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// CHECK: bb0([[ISOLATION:%.*]] : @guaranteed $Optional<any Actor>)
+// CHECK: bb1([[FN:%.*]] : @owned $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ())
+// CHECK: [[BORROWED_FN:%.*]] = begin_borrow [[FN]]
+// CHECK: apply [[BORROWED_FN]]([[ISOLATION]]) : $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+// CHECK: } // end sil function '$s14attr_execution9testLocalyyYaF'
+func testLocal() async {
+  let fn: (() async -> Void)? = nil
+  await fn?()
+}
+
+// CHECK-LABEL: // takesClosure(fn:)
+// CHECK: // Isolation: unspecified
+// CHECK: sil hidden [ossa] @$s14attr_execution12takesClosure2fnyyyYaYCXE_tF : $@convention(thin) (@guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
+func takesClosure(fn: () async -> Void) {
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s14attr_execution11testClosureyyF : $@convention(thin) () -> ()
+// CHECK:  [[CLOSURE:%.*]] = function_ref @$s14attr_execution11testClosureyyFyyYaYCXEfU_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+// CHECK:  [[THUNKED_CLOSURE:%.*]] = thin_to_thick_function %0 to $@noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+// CHECK:  [[TAKES_CLOSURE:%.*]] = function_ref @$s14attr_execution12takesClosure2fnyyyYaYCXE_tF : $@convention(thin) (@guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
+// CHECK:  apply [[TAKES_CLOSURE]]([[THUNKED_CLOSURE]])
+// CHECK: } // end sil function '$s14attr_execution11testClosureyyF'
+
+// CHECK-LABEL: // closure #1 in testClosure()
+// CHECK: // Isolation: caller_isolation_inheriting
+// CHECK: sil private [ossa] @$s14attr_execution11testClosureyyFyyYaYCXEfU_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+func testClosure() {
+  takesClosure {
+  }
+}
+
+protocol P {
+}
+
+func open<T: P>(_: T) async {}
+
+// CHECK-LABEL: sil hidden [ossa] @$s14attr_execution19testOpenExistential11existentialyAA1P_p_tYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed any P) -> ()
+// CHECK: bb0([[ISOLATION:%.*]] : @guaranteed $Optional<any Actor>, [[EXISTENTIAL:%.*]] : $*any P):
+// CHECK: [[OPEN_REF:%.*]] = function_ref @$s14attr_execution4openyyxYaAA1PRzlF
+// CHECK: apply [[OPEN_REF]]<@opened("{{.*}}", any P) Self>([[ISOLATION]], {{.*}})
+// CHECK: } // end sil function '$s14attr_execution19testOpenExistential11existentialyAA1P_p_tYaF'
+func testOpenExistential(existential: any P) async {
+  await _openExistential(existential, do: open)
+}
+
+func testWithoutActuallyEscaping(_ f: () async -> ()) async {
+  // CHECK-LABEL: // closure #1 in testWithoutActuallyEscaping(_:)
+  // CHECK-NEXT: // Isolation: caller_isolation_inheriting
+  await withoutActuallyEscaping(f) {
+    await $0()
+  }
+
+  // CHECK-LABEL: // closure #2 in testWithoutActuallyEscaping(_:)
+  // CHECK-NEXT: // Isolation: global_actor. type: MainActor
+  await withoutActuallyEscaping(f) { @MainActor in
+    await $0()
+  }
+
+  actor Test {
+    // CHECK-LABEL: // closure #1 in testActorIsolatedCapture() in Test #1 in testWithoutActuallyEscaping(_:)
+    // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
+    func testActorIsolatedCapture() async {
+      await withoutActuallyEscaping(compute) {
+        _ = self
+        await $0()
+      }
+    }
+
+    func compute() async {}
+  }
+}
diff --git a/test/Concurrency/attr_execution/classes_silgen.swift b/test/Concurrency/attr_execution/classes_silgen.swift
new file mode 100644
index 0000000000000..fe82210ff52a9
--- /dev/null
+++ b/test/Concurrency/attr_execution/classes_silgen.swift
@@ -0,0 +1,80 @@
+// RUN: %target-swift-emit-silgen %s -module-name attr_execution_silgen -target %target-swift-5.1-abi-triple -DSWIFT_FIVE | %FileCheck --implicit-check-not=thunk %s
+// RUN: %target-swift-emit-silgen %s -swift-version 6 -module-name attr_execution_silgen -target %target-swift-5.1-abi-triple | %FileCheck --implicit-check-not=thunk %s
+
+// REQUIRES: asserts
+// REQUIRES: concurrency
+
+// We should only produce thunks when going to/from nonisolated(nonsending)
+// since that is the only thing that makes a true ABI change since we have an
+// extra parameter.
+
+// NOTE: We use implicit-check-not to make sure we do not create any other
+// thunks beyond the ones we pattern match.
+
+class SuperKlass {
+  nonisolated(nonsending) func callerTest() async {}
+  @concurrent func concurrentTest() async {}
+  @MainActor func mainActorTest() async {}
+}
+
+class AllDefault : SuperKlass {
+  // This doesn't need a thunk since we infer it is nonisolated(nonsending).
+  override func callerTest() async {}
+  override func concurrentTest() async {}
+  override func mainActorTest() async {}
+}
+
+class AllConcurrent : SuperKlass {
+  // CHECK-LABEL: vtable thunk for SuperKlass.callerTest() dispatching to AllConcurrent.callerTest()
+  // CHECK-NEXT: sil private [thunk] [ossa] @$s21attr_execution_silgen13AllConcurrentC10callerTestyyYaFAA10SuperKlassCADyyYaFTV : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed AllConcurrent) -> () {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[PARAM:%.*]] : @guaranteed $AllConcurrent):
+  // CHECK:  [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen13AllConcurrentC10callerTestyyYaF : $@convention(method) @async (@guaranteed AllConcurrent) -> ()
+  // CHECK:  apply [[FUNC]]([[PARAM]])
+  // CHECK:  hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s21attr_execution_silgen13AllConcurrentC10callerTestyyYaFAA10SuperKlassCADyyYaFTV'
+  @concurrent override func callerTest() async {}
+  @concurrent override func concurrentTest() async {}
+  @concurrent override func mainActorTest() async {}
+}
+
+class AllNonIsolatedUnsafe : SuperKlass {
+  override nonisolated(nonsending) func callerTest() async {}
+
+  // CHECK-LABEL: // vtable thunk for SuperKlass.concurrentTest() dispatching to AllNonIsolatedUnsafe.concurrentTest()
+  // CHECK-NEXT: sil private [thunk] [ossa] @$s21attr_execution_silgen20AllNonIsolatedUnsafeC14concurrentTestyyYaFAA10SuperKlassCADyyYaFTV : $@convention(method) @async (@guaranteed AllNonIsolatedUnsafe) -> () {
+  // CHECK: bb0([[ARG:%.*]] : @guaranteed
+  // CHECK:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen20AllNonIsolatedUnsafeC14concurrentTestyyYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed AllNonIsolatedUnsafe) -> ()
+  // CHECK:   apply [[FUNC]]([[ACTOR]], [[ARG]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen20AllNonIsolatedUnsafeC14concurrentTestyyYaFAA10SuperKlassCADyyYaFTV'
+  override nonisolated(nonsending) func concurrentTest() async {}
+
+  // CHECK-LABEL: // vtable thunk for SuperKlass.mainActorTest() dispatching to AllNonIsolatedUnsafe.mainActorTest()
+  // CHECK-NEXT: sil private [thunk] [ossa] @$s21attr_execution_silgen20AllNonIsolatedUnsafeC13mainActorTestyyYaFAA10SuperKlassCADyyYaFTV : $@convention(method) @async (@guaranteed AllNonIsolatedUnsafe) -> () {
+  // CHECK: bb0([[ARG:%.*]] : @guaranteed $AllNonIsolatedUnsafe):
+  // CHECK:   [[ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+  // CHECK:   [[ACTOR_E:%.*]] = init_existential_ref [[ACTOR]]
+  // CHECK:   [[ACTOR_E_OPT:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[ACTOR_E]]
+  // CHECK:   hop_to_executor [[ACTOR_E_OPT]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen20AllNonIsolatedUnsafeC13mainActorTestyyYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed AllNonIsolatedUnsafe) -> ()
+  // CHECK:   apply [[FUNC]]([[ACTOR_E_OPT]], [[ARG]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen20AllNonIsolatedUnsafeC13mainActorTestyyYaFAA10SuperKlassCADyyYaFTV'
+  override nonisolated(nonsending) func mainActorTest() async {}
+}
+
+// CHECK-LABEL: sil_vtable AllConcurrent {
+// CHECK-NEXT:   #SuperKlass.callerTest: (SuperKlass) -> () async -> () : @$s21attr_execution_silgen13AllConcurrentC10callerTestyyYaFAA10SuperKlassCADyyYaFTV [override]	// vtable thunk for SuperKlass.callerTest() dispatching to AllConcurrent.callerTest()
+// CHECK-NEXT:   #SuperKlass.concurrentTest: (SuperKlass) -> () async -> () : @$s21attr_execution_silgen13AllConcurrentC14concurrentTestyyYaF [override]	// AllConcurrent.concurrentTest()
+// CHECK-NEXT:   #SuperKlass.mainActorTest: (SuperKlass) -> () async -> () : @$s21attr_execution_silgen13AllConcurrentC13mainActorTestyyYaF [override]	// AllConcurrent.mainActorTest()
+// CHECK-NEXT:   #SuperKlass.init!allocator: (SuperKlass.Type) -> () -> SuperKlass : @$s21attr_execution_silgen13AllConcurrentCACycfC [override]	// AllConcurrent.__allocating_init()
+// CHECK-NEXT:   #AllConcurrent.deinit!deallocator: @$s21attr_execution_silgen13AllConcurrentCfD	// AllConcurrent.__deallocating_deinit
+// CHECK-NEXT: }
+
+// CHECK-LABEL: sil_vtable AllNonIsolatedUnsafe {
+// CHECK-NEXT:   #SuperKlass.callerTest: (SuperKlass) -> () async -> () : @$s21attr_execution_silgen20AllNonIsolatedUnsafeC10callerTestyyYaF [override]	// AllNonIsolatedUnsafe.callerTest()
+// CHECK-NEXT:   #SuperKlass.concurrentTest: (SuperKlass) -> () async -> () : @$s21attr_execution_silgen20AllNonIsolatedUnsafeC14concurrentTestyyYaFAA10SuperKlassCADyyYaFTV [override]	// vtable thunk for SuperKlass.concurrentTest() dispatching to AllNonIsolatedUnsafe.concurrentTest()
+// CHECK-NEXT:   #SuperKlass.mainActorTest: (SuperKlass) -> () async -> () : @$s21attr_execution_silgen20AllNonIsolatedUnsafeC13mainActorTestyyYaFAA10SuperKlassCADyyYaFTV [override]	// vtable thunk for SuperKlass.mainActorTest() dispatching to AllNonIsolatedUnsafe.mainActorTest()
+// CHECK-NEXT:   #SuperKlass.init!allocator: (SuperKlass.Type) -> () -> SuperKlass : @$s21attr_execution_silgen20AllNonIsolatedUnsafeCACycfC [override]	// AllNonIsolatedUnsafe.__allocating_init()
+// CHECK-NEXT:   #AllNonIsolatedUnsafe.deinit!deallocator: @$s21attr_execution_silgen20AllNonIsolatedUnsafeCfD	// AllNonIsolatedUnsafe.__deallocating_deinit
+// CHECK-NEXT: }
diff --git a/test/Concurrency/attr_execution/conversions.swift b/test/Concurrency/attr_execution/conversions.swift
index 3113724468061..01db388c9d94a 100644
--- a/test/Concurrency/attr_execution/conversions.swift
+++ b/test/Concurrency/attr_execution/conversions.swift
@@ -1,69 +1,64 @@
-// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple -enable-experimental-feature ExecutionAttribute
+// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_ExecutionAttribute
 
 @globalActor
 actor MyActor {
   static let shared = MyActor()
 }
 
-@execution(concurrent)
+@concurrent
 func concurrentTest() async {
 }
 
-@execution(caller)
+nonisolated(nonsending)
 func callerTest() async {
 }
 
 @MainActor
 func actorIsolated() async {}
 
-let _: @execution(caller) () async -> Void = concurrentTest // Ok
-let _: @execution(concurrent) () async -> Void = callerTest // Ok
+let _: nonisolated(nonsending) () async -> Void = concurrentTest // Ok
+let _: @concurrent () async -> Void = callerTest // Ok
 
 let _: @MainActor () async -> Void = concurrentTest // Ok
 let _: @MainActor () async -> Void = callerTest // Ok
 
 let _: @isolated(any) () async -> Void = concurrentTest // Ok
 let _: @isolated(any) () async -> Void = callerTest
-// expected-error@-1 {{cannot convert value of type '@execution(caller) () async -> ()' to specified type '@isolated(any) () async -> Void'}}
+// expected-error@-1 {{cannot convert value of type 'nonisolated(nonsending) () async -> ()' to specified type '@isolated(any) () async -> Void'}}
 
-let _: @execution(caller) () async -> Void = actorIsolated // Ok
-let _: @execution(concurrent) () async -> Void = actorIsolated // Ok
+let _: nonisolated(nonsending) () async -> Void = actorIsolated // Ok
+let _: @concurrent () async -> Void = actorIsolated // Ok
 
 func testIsolationErasure(fn: @escaping @isolated(any) () async -> Void) {
-  let _: @execution(concurrent) () async -> Void = fn // Ok
-  let _: @execution(caller) () async -> Void = fn // Ok
+  let _: @concurrent () async -> Void = fn // Ok
+  let _: nonisolated(nonsending) () async -> Void = fn // Ok
 }
 
-func testUpcast(arr: [@execution(caller) () async -> Void]) {
+func testUpcast(arr: [nonisolated(nonsending) () async -> Void]) {
   let _: [() async -> Void] = arr // Ok - collection upcast
   let _: [String: () async -> Void] = ["": arr]
-  // expected-error@-1 {{cannot convert value of type '[@execution(caller) () async -> Void]' to expected dictionary value type '() async -> Void'}}
+  // expected-error@-1 {{cannot convert value of type '[nonisolated(nonsending) () async -> Void]' to expected dictionary value type '() async -> Void'}}
 }
 
 // Isolated parameter
-func testParameterIsolation(fn: @escaping (isolated (any Actor)?) async -> Void, caller: @escaping @execution(caller) (String) async -> Void) {
-  let _: @execution(caller) () async -> Void = fn
-  // expected-error@-1 {{cannot convert value of type '(isolated (any Actor)?) async -> Void' to specified type '@execution(caller) () async -> Void'}}
-  let _: @execution(concurrent) () async -> Void = fn
+func testParameterIsolation(fn: @escaping (isolated (any Actor)?) async -> Void, caller: nonisolated(nonsending) @escaping (String) async -> Void) {
+  let _: nonisolated(nonsending) () async -> Void = fn
+  // expected-error@-1 {{cannot convert value of type '(isolated (any Actor)?) async -> Void' to specified type 'nonisolated(nonsending) () async -> Void'}}
+  let _: @concurrent () async -> Void = fn
   // expected-error@-1 {{cannot convert value of type '(isolated (any Actor)?) async -> Void' to specified type '() async -> Void'}}
 
   let _: (isolated (any Actor)?) async -> Void = callerTest // Ok
   let _: (isolated (any Actor)?) -> Void = callerTest
-  // expected-error@-1 {{invalid conversion from 'async' function of type '@execution(caller) () async -> ()' to synchronous function type '(isolated (any Actor)?) -> Void'}}
+  // expected-error@-1 {{invalid conversion from 'async' function of type 'nonisolated(nonsending) () async -> ()' to synchronous function type '(isolated (any Actor)?) -> Void'}}
   let _: (isolated (any Actor)?) async -> Void = concurrentTest
   // expected-error@-1 {{cannot convert value of type '() async -> ()' to specified type '(isolated (any Actor)?) async -> Void'}}
   let _: (isolated (any Actor)?, Int) async -> Void = callerTest
-  // expected-error@-1 {{cannot convert value of type '@execution(caller) () async -> ()' to specified type '(isolated (any Actor)?, Int) async -> Void'}}
+  // expected-error@-1 {{cannot convert value of type 'nonisolated(nonsending) () async -> ()' to specified type '(isolated (any Actor)?, Int) async -> Void'}}
 
   let _: (String, isolated any Actor) async -> Void = caller // Ok
   let _: (isolated (any Actor)?, String) async -> Void = caller // Ok
-
-  let _: (Int, isolated any Actor) async -> Void = { @execution(caller) x in } // Ok
-  let _: (Int, isolated any Actor) async -> Void = { @execution(caller) (x: Int) in } // Ok
-  let _: (isolated any Actor, Int, String) async -> Void = { @execution(caller) (x: Int, _: String) in } // Ok
 }
 
 // Non-conversion situations
@@ -73,19 +68,19 @@ do {
   func test<T>(_: S<T>, _: T.Type) {}
   
   test(S<() async -> Void>(), type(of: callerTest))
-  // expected-error@-1 {{cannot convert value of type '(@execution(caller) () async -> ()).Type' to expected argument type '(() async -> Void).Type'}}
+  // expected-error@-1 {{cannot convert value of type '(nonisolated(nonsending) () async -> ()).Type' to expected argument type '(() async -> Void).Type'}}
 
-  test(S<@execution(caller) () async -> Void>(), type(of: concurrentTest))
-  // expected-error@-1 {{cannot convert value of type '(() async -> ()).Type' to expected argument type '(@execution(caller) () async -> Void).Type'}}
+  test(S<nonisolated(nonsending) () async -> Void>(), type(of: concurrentTest))
+  // expected-error@-1 {{cannot convert value of type '(() async -> ()).Type' to expected argument type '(nonisolated(nonsending) () async -> Void).Type'}}
 
   test(S<@MainActor () async -> Void>(), type(of: callerTest))
-  // expected-error@-1 {{cannot convert value of type '(@execution(caller) () async -> ()).Type' to expected argument type '(@MainActor () async -> Void).Type'}}
+  // expected-error@-1 {{cannot convert value of type '(nonisolated(nonsending) () async -> ()).Type' to expected argument type '(@MainActor () async -> Void).Type'}}
 
   test(S<@MainActor () async -> Void>(), type(of: concurrentTest))
   // expected-error@-1 {{cannot convert value of type '(() async -> ()).Type' to expected argument type '(@MainActor () async -> Void).Type'}}
 
   test(S<(isolated (any Actor)?) async -> Void>(), type(of: callerTest))
-  // expected-error@-1 {{cannot convert value of type '(@execution(caller) () async -> ()).Type' to expected argument type '((isolated (any Actor)?) async -> Void).Type'}}
+  // expected-error@-1 {{cannot convert value of type '(nonisolated(nonsending) () async -> ()).Type' to expected argument type '((isolated (any Actor)?) async -> Void).Type'}}
 
   test(S<(isolated (any Actor)?) async -> Void>(), type(of: concurrentTest))
   // expected-error@-1 {{cannot convert value of type '(() async -> ()).Type' to expected argument type '((isolated (any Actor)?) async -> Void).Type'}}
@@ -93,22 +88,16 @@ do {
   test(S<@isolated(any) () async -> Void>(), type(of: concurrentTest))
   // expected-error@-1 {{cannot convert value of type '(() async -> ()).Type' to expected argument type '(@isolated(any) () async -> Void).Type'}}
   test(S<@isolated(any) () async -> Void>(), type(of: callerTest))
-  // expected-error@-1 {{cannot convert value of type '(@execution(caller) () async -> ()).Type' to expected argument type '(@isolated(any) () async -> Void).Type'}}
+  // expected-error@-1 {{cannot convert value of type '(nonisolated(nonsending) () async -> ()).Type' to expected argument type '(@isolated(any) () async -> Void).Type'}}
 }
 
 do {
-  let _: () -> Void = { @execution(concurrent) in
-    // expected-error@-1 {{invalid conversion from 'async' function of type '() async -> Void' to synchronous function type '() -> Void'}}
-  }
-
-  func test(_: () -> Void) {}
-
-  test { @execution(caller) in
-    // expected-error@-1 {{cannot pass function of type '@execution(caller) () async -> ()' to parameter expecting synchronous function type}}
+  let _: () -> Void = { @concurrent in
+    // expected-error@-1 {{cannot use @concurrent on non-async closure}}{{none}}
   }
 }
 
-// Converting to `@execution(caller)` function
+// Converting to `nonisolated(nonsending)` function
 class NonSendable {}
 
 func testNonSendableDiagnostics(
@@ -117,40 +106,45 @@ func testNonSendableDiagnostics(
   erased1: @escaping @Sendable @isolated(any) (NonSendable) async -> Void,
   erased2: @escaping @Sendable @isolated(any) () async -> NonSendable,
   nonIsolated1: @escaping @Sendable (NonSendable) -> Void,
-  nonIsolated2: @escaping @Sendable @execution(concurrent) (NonSendable) async -> Void,
+  nonIsolated2: @escaping @Sendable @concurrent (NonSendable) async -> Void,
   nonIsolated3: @escaping @Sendable () -> NonSendable,
-  nonIsolated4: @escaping @Sendable @execution(concurrent) () async -> NonSendable,
-  caller1: @escaping @Sendable @execution(caller) (NonSendable) async -> Void,
-  caller2: @escaping @Sendable @execution(caller) () async -> NonSendable
+  nonIsolated4: @escaping @Sendable @concurrent () async -> NonSendable,
+  caller1: nonisolated(nonsending) @escaping @Sendable (NonSendable) async -> Void,
+  caller2: nonisolated(nonsending) @escaping @Sendable () async -> NonSendable
 ) {
-  let _: @execution(caller) (NonSendable) async -> Void = globalActor1 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
-  // expected-error@-1 {{cannot convert '@MainActor @Sendable (NonSendable) async -> Void' to '@execution(caller) (NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
-  let _: @execution(caller) () async -> NonSendable = globalActor2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
-  // expected-error@-1 {{cannot convert '@MainActor @Sendable () async -> NonSendable' to '@execution(caller) () async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
-
-  let _: @execution(caller) (NonSendable) async -> Void = erased1 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
-  // expected-error@-1 {{cannot convert '@isolated(any) @Sendable (NonSendable) async -> Void' to '@execution(caller) (NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
-  let _: @execution(caller) () async -> NonSendable = erased2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
-  // expected-error@-1 {{cannot convert '@isolated(any) @Sendable () async -> NonSendable' to '@execution(caller) () async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+  let _: nonisolated(nonsending) (NonSendable) async -> Void = globalActor1 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-error@-1 {{cannot convert '@MainActor @Sendable (NonSendable) async -> Void' to 'nonisolated(nonsending) (NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+  let _: nonisolated(nonsending) () async -> NonSendable = globalActor2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-error@-1 {{cannot convert '@MainActor @Sendable () async -> NonSendable' to 'nonisolated(nonsending) () async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+
+  let _: @concurrent (NonSendable) async -> Void = globalActor1 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-warning@-1 {{cannot convert '@MainActor @Sendable (NonSendable) async -> Void' to '(NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+  let _: @concurrent () async -> NonSendable = globalActor2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-warning@-1 {{cannot convert '@MainActor @Sendable () async -> NonSendable' to '() async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+  
+  let _: nonisolated(nonsending) (NonSendable) async -> Void = erased1 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-error@-1 {{cannot convert '@isolated(any) @Sendable (NonSendable) async -> Void' to 'nonisolated(nonsending) (NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+  let _: nonisolated(nonsending) () async -> NonSendable = erased2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-error@-1 {{cannot convert '@isolated(any) @Sendable () async -> NonSendable' to 'nonisolated(nonsending) () async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
 
-  let _: @execution(caller) (NonSendable) async -> Void = nonIsolated1 // Ok
-  let _: @execution(caller) (NonSendable) async -> Void = nonIsolated2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
-  // expected-error@-1 {{cannot convert '@Sendable (NonSendable) async -> Void' to '@execution(caller) (NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+  let _: nonisolated(nonsending) (NonSendable) async -> Void = nonIsolated1 // Ok
+  let _: nonisolated(nonsending) (NonSendable) async -> Void = nonIsolated2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-error@-1 {{cannot convert '@Sendable (NonSendable) async -> Void' to 'nonisolated(nonsending) (NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
 
-  let _: @execution(caller) () async -> NonSendable = nonIsolated3 // Ok
-  let _: @execution(caller) () async -> NonSendable = nonIsolated4 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
-  // expected-error@-1 {{cannot convert '@Sendable () async -> NonSendable' to '@execution(caller) () async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+  let _: nonisolated(nonsending) () async -> NonSendable = nonIsolated3 // Ok
+  let _: nonisolated(nonsending) () async -> NonSendable = nonIsolated4 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-error@-1 {{cannot convert '@Sendable () async -> NonSendable' to 'nonisolated(nonsending) () async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
 
-  let _: @execution(concurrent) (NonSendable) async -> Void = erased1 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  let _: @concurrent (NonSendable) async -> Void = erased1 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
   // expected-warning@-1 {{cannot convert '@isolated(any) @Sendable (NonSendable) async -> Void' to '(NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
-  let _: @execution(concurrent) () async -> NonSendable = erased2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  let _: @concurrent () async -> NonSendable = erased2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
   // expected-warning@-1 {{cannot convert '@isolated(any) @Sendable () async -> NonSendable' to '() async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
 
 
-  let _: @execution(concurrent) (NonSendable) async -> Void = caller1 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
-  // expected-warning@-1 {{cannot convert '@execution(caller) @Sendable (NonSendable) async -> Void' to '(NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
-  let _: @execution(concurrent) () async -> NonSendable = caller2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
-  // expected-warning@-1 {{cannot convert '@execution(caller) @Sendable () async -> NonSendable' to '() async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+  let _: @concurrent (NonSendable) async -> Void = caller1 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-warning@-1 {{cannot convert 'nonisolated(nonsending) @Sendable (NonSendable) async -> Void' to '(NonSendable) async -> Void' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+  let _: @concurrent () async -> NonSendable = caller2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  // expected-warning@-1 {{cannot convert 'nonisolated(nonsending) @Sendable () async -> NonSendable' to '() async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
 
   let _: @MainActor (NonSendable) async -> Void = nonIsolated1 // Ok
   let _: @MainActor (NonSendable) async -> Void = nonIsolated2 // expected-note {{type 'NonSendable' does not conform to 'Sendable' protocol}}
diff --git a/test/Concurrency/attr_execution/conversions_silgen.swift b/test/Concurrency/attr_execution/conversions_silgen.swift
new file mode 100644
index 0000000000000..048b7efefe350
--- /dev/null
+++ b/test/Concurrency/attr_execution/conversions_silgen.swift
@@ -0,0 +1,645 @@
+// RUN: %target-swift-emit-silgen %s -module-name attr_execution_silgen -target %target-swift-5.1-abi-triple -DSWIFT_FIVE | %FileCheck -check-prefix CHECK -check-prefix FIVE %s
+// RUN: %target-swift-emit-silgen %s -swift-version 6 -module-name attr_execution_silgen -target %target-swift-5.1-abi-triple | %FileCheck -check-prefix CHECK -check-prefix SIX %s
+
+// We codegen slightly differently for swift 5 vs swift 6, so we need to check
+// both.
+
+// REQUIRES: asserts
+// REQUIRES: concurrency
+
+////////////////////////
+// MARK: Declarations //
+////////////////////////
+
+nonisolated(nonsending)
+func globalCallerFunc() async -> () {}
+
+@concurrent
+func globalConcurrentFunc() async -> () {}
+
+class NonSendableKlass {
+  init() {}
+}
+class SendableKlass : @unchecked Sendable {
+  init() {}
+}
+
+nonisolated(nonsending)
+func globalCallerFuncSendableKlass(_ x: SendableKlass) async -> () {}
+
+@concurrent
+func globalConcurrentFuncSendableKlass(_ x: SendableKlass) async -> () {}
+
+nonisolated(nonsending)
+func globalCallerFuncSendableKlass(_ x: SendableKlass) async -> SendableKlass { fatalError() }
+
+@concurrent
+func globalConcurrentFuncSendableKlass(_ x: SendableKlass) async -> SendableKlass { fatalError() }
+
+
+/////////////////
+// MARK: Tests //
+/////////////////
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen33testCallerToConcurrentNonIsolatedyyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
+// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
+// CHECK:   [[FUNC_COPY:%.*]] = copy_value [[FUNC]]
+// CHECK:   [[THUNK:%.*]] = function_ref @$sScA_pSgIegHgIL_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
+// CHECK:   partial_apply [callee_guaranteed] [[THUNK]]([[FUNC_COPY]])
+// CHECK: } // end sil function '$s21attr_execution_silgen33testCallerToConcurrentNonIsolatedyyyyYaYCcYaF'
+public func testCallerToConcurrentNonIsolated(_ x: nonisolated(nonsending) @escaping () async -> ()) async {
+  let y: @concurrent () async -> () = x
+  await y()
+}
+
+// This thunk is used to convert a caller to a concurrent function. So, we pass in .none as the
+// isolated parameter.
+//
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSgIegHgIL_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
+// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
+// CHECK:   [[ENUM:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK:   hop_to_executor [[ENUM]]
+// CHECK:   apply [[FUNC]]([[ENUM]])
+// CHECK: } // end sil function '$sScA_pSgIegHgIL_IegH_TR'
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen31testCallerToConcurrentMainActoryyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
+// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
+// CHECK:   [[FUNC_COPY:%.*]] = copy_value [[FUNC]]
+// CHECK:   [[THUNK:%.*]] = function_ref @$sScA_pSgIegHgIL_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
+// CHECK:   partial_apply [callee_guaranteed] [[THUNK]]([[FUNC_COPY]])
+// CHECK: } // end sil function '$s21attr_execution_silgen31testCallerToConcurrentMainActoryyyyYaYCcYaF'
+@MainActor
+public func testCallerToConcurrentMainActor(_ x: nonisolated(nonsending) @escaping () async -> ()) async {
+  let y: @concurrent () async -> () = x
+  await y()
+}
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen33testConcurrentToCallerNonIsolatedyyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
+// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed () -> ()):
+// CHECK:   [[FUNC_COPY:%.*]] = copy_value [[FUNC]]
+// CHECK:   [[THUNK:%.*]] = function_ref @$sIegH_ScA_pSgIegHgIL_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> ()
+// CHECK:   partial_apply [callee_guaranteed] [[THUNK]]([[FUNC_COPY]])
+// CHECK: } // end sil function '$s21attr_execution_silgen33testConcurrentToCallerNonIsolatedyyyyYacYaF'
+public func testConcurrentToCallerNonIsolated(_ x: @escaping @concurrent () async -> ()) async {
+  let y: nonisolated(nonsending) () async -> () = x
+  await y()
+}
+
+// This thunk has the "surface" of an @caller function, but just ignores the
+// isolated parameter and calls the concurrent funciton.
+//
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sIegH_ScA_pSgIegHgIL_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> () {
+// CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed () -> ()):
+// CHECK:   apply [[FUNC]]
+// CHECK:   hop_to_executor [[ACTOR]]
+// CHECK: } // end sil function '$sIegH_ScA_pSgIegHgIL_TR'
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen42testConcurrentToCallerNonIsolatedMainActoryyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
+// CHECK: bb0([[FUNC:%.*]] :
+// CHECK:   [[FUNC_COPY:%.*]] = copy_value [[FUNC]]
+// CHECK:   [[THUNK:%.*]] = function_ref @$sIegH_ScA_pSgIegHgIL_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> ()
+// CHECK:   partial_apply [callee_guaranteed] [[THUNK]]([[FUNC_COPY]])
+// CHECK: } // end sil function '$s21attr_execution_silgen42testConcurrentToCallerNonIsolatedMainActoryyyyYacYaF'
+@MainActor
+public func testConcurrentToCallerNonIsolatedMainActor(_ x: @escaping @concurrent () async -> ()) async {
+  let y: nonisolated(nonsending) () async -> () = x
+  await y()
+}
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen016testConcurrentToE0yyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
+// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed () -> ()):
+// CHECK:   [[COPY:%.*]] = copy_value [[FUNC]]
+// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[COPY]]
+// CHECK:   [[BORROW_Y:%.*]] = begin_borrow [[Y]]
+// CHECK:   [[COPY_Y:%.*]] = copy_value [[BORROW_Y]]
+// CHECK:   [[BORROW_COPY_Y:%.*]] = begin_borrow [[COPY_Y]]
+// CHECK:   apply [[BORROW_COPY_Y]]()
+// CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen20globalConcurrentFuncyyYaF : $@convention(thin) @async () -> ()
+// CHECK:   [[TTFI:%.*]] = thin_to_thick_function [[FUNC]]
+// FIVE:    [[Z:%.*]] = move_value [lexical] [var_decl] [[TTFI]]
+// SIX:     [[CVT_1:%.*]] = convert_function [[TTFI]] to $@Sendable @async
+// SIX:     [[CVT_2:%.*]] = convert_function [[CVT_1]] to $@async
+// SIX:     [[Z:%.*]] = move_value [lexical] [var_decl] [[CVT_2]]
+// CHECK:   [[BORROW_Z:%.*]] = begin_borrow [[Z]]
+// CHECK:   [[COPY_Z:%.*]] = copy_value [[BORROW_Z]]
+// CHECK:   [[BORROW_COPY_Z:%.*]] = begin_borrow [[COPY_Z]]
+// CHECK:   apply [[BORROW_COPY_Z]]()
+// CHECK: } // end sil function '$s21attr_execution_silgen016testConcurrentToE0yyyyYacYaF'
+public func testConcurrentToConcurrent(_ x: @escaping @concurrent () async -> ()) async {
+  let y: @concurrent () async -> () = x
+  await y()
+  let z: @concurrent () async -> () = globalConcurrentFunc
+  await z()
+}
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen012testCallerToE0yyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
+// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
+// CHECK:   [[COPY:%.*]] = copy_value [[FUNC]]
+// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[COPY]]
+// CHECK:   [[BORROW_Y:%.*]] = begin_borrow [[Y]]
+// CHECK:   [[COPY_Y:%.*]] = copy_value [[BORROW_Y]]
+// CHECK:   [[BORROW_COPY_Y:%.*]] = begin_borrow [[COPY_Y]]
+// CHECK:   apply [[BORROW_COPY_Y]]({{%.*}})
+// CHECK: } // end sil function '$s21attr_execution_silgen012testCallerToE0yyyyYaYCcYaF'
+//
+// z has a round trip issue.
+public func testCallerToCaller(_ x: nonisolated(nonsending) @escaping () async -> ()) async {
+  let y: nonisolated(nonsending) () async -> () = x
+  await y()
+  let z: nonisolated(nonsending) () async -> () = globalCallerFunc
+  await z()
+}
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen24testCallerLocalVariablesyyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
+// CHECK: bb0([[PARAM:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
+// CHECK:   [[PARAM_COPY:%.*]] = copy_value [[PARAM]]
+// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[PARAM_COPY]]
+// CHECK:   [[Y_B:%.*]] = begin_borrow [[Y]]
+// CHECK:   [[Y_B_C:%.*]] = copy_value [[Y_B]]
+// CHECK:   [[Y2:%.*]] = move_value [lexical] [var_decl] [[Y_B_C]]
+// CHECK:   [[Y2_B:%.*]] = begin_borrow [[Y2]]
+// CHECK:   [[Y2_B_C:%.*]] = copy_value [[Y2_B]]
+// CHECK:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK:   [[Y2_B_C_B:%.*]] = begin_borrow [[Y2_B_C]]
+// CHECK:   apply [[Y2_B_C_B]]([[ACTOR]])
+// CHECK: } // end sil function '$s21attr_execution_silgen24testCallerLocalVariablesyyyyYaYCcYaF'
+public func testCallerLocalVariables(_ x: nonisolated(nonsending) @escaping () async -> ()) async {
+  let y: nonisolated(nonsending) () async -> () = x
+  let y2: nonisolated(nonsending) () async -> () = y
+  await y2()
+}
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen28testConcurrentLocalVariablesyyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
+// CHECK:   [[PARAM_COPY:%.*]] = copy_value [[PARAM]]
+// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[PARAM_COPY]]
+// CHECK:   [[Y_B:%.*]] = begin_borrow [[Y]]
+// CHECK:   [[Y_B_C:%.*]] = copy_value [[Y_B]]
+// CHECK:   [[Y2:%.*]] = move_value [lexical] [var_decl] [[Y_B_C]]
+// CHECK:   [[Y2_B:%.*]] = begin_borrow [[Y2]]
+// CHECK:   [[Y2_B_C:%.*]] = copy_value [[Y2_B]]
+// CHECK:   [[Y2_B_C_B:%.*]] = begin_borrow [[Y2_B_C]]
+// CHECK:   apply [[Y2_B_C_B]]()
+// CHECK: } // end sil function '$s21attr_execution_silgen28testConcurrentLocalVariablesyyyyYacYaF'
+public func testConcurrentLocalVariables(_ x: @escaping @concurrent () async -> ()) async {
+  let y: @concurrent () async -> () = x
+  let y2: @concurrent () async -> () = y
+  await y2()
+}
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen34testCallerConcurrentLocalVariablesyyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
+// CHECK: bb0([[PARAM:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
+// CHECK:   [[PARAM_COPY:%.*]] = copy_value [[PARAM]]
+// CHECK:   [[THUNK_1:%.*]] = function_ref @$sScA_pSgIegHgIL_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
+// CHECK:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK_1]]([[PARAM_COPY]])
+// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[PA]]
+// CHECK:   [[Y_B:%.*]] = begin_borrow [[Y]]
+// CHECK:   [[Y_B_C:%.*]] = copy_value [[Y_B]]
+// CHECK:   [[THUNK_2:%.*]] = function_ref @$sIegH_ScA_pSgIegHgIL_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> ()
+// CHECK:   [[PA_2:%.*]] = partial_apply [callee_guaranteed] [[THUNK_2]]([[Y_B_C]])
+// CHECK: } // end sil function '$s21attr_execution_silgen34testCallerConcurrentLocalVariablesyyyyYaYCcYaF'
+public func testCallerConcurrentLocalVariables(_ x: nonisolated(nonsending) @escaping () async -> ()) async {
+  let y: @concurrent () async -> () = x
+  let y2: nonisolated(nonsending) () async -> () = y
+  await y2()
+}
+
+// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen34testConcurrentCallerLocalVariablesyyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
+// CHECK: bb0([[PARAM:%.*]] : @guaranteed $@async @callee_guaranteed () -> ()):
+// CHECK:   [[PARAM_C:%.*]] = copy_value [[PARAM]]
+// CHECK:   [[THUNK_1:%.*]] = function_ref @$sIegH_ScA_pSgIegHgIL_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> ()
+// CHECK:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK_1]]([[PARAM_C]])
+// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[PA]]
+// CHECK:   [[Y_B:%.*]] = begin_borrow [[Y]]
+// CHECK:   [[Y_B_C:%.*]] = copy_value [[Y_B]]
+// CHECK:   [[THUNK_2:%.*]] = function_ref @$sScA_pSgIegHgIL_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
+// CHECK:   [[PA_2:%.*]] = partial_apply [callee_guaranteed] [[THUNK_2]]([[Y_B_C]])
+// CHECK: } // end sil function '$s21attr_execution_silgen34testConcurrentCallerLocalVariablesyyyyYacYaF'
+public func testConcurrentCallerLocalVariables(_ x: @escaping @concurrent () async -> ()) async {
+  let y: nonisolated(nonsending) () async -> () = x
+  let y2: @concurrent () async -> () = y
+  await y2()
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen22globalActorConversionsyyyyYac_yyYaYCctYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> (), @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
+// CHECK: bb0([[X:%.*]] : @guaranteed $@async @callee_guaranteed () -> (), [[Y:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
+// CHECK:   [[GLOBAL_CALLER_FUNC:%.*]] = function_ref @$s21attr_execution_silgen16globalCallerFuncyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+// FIVE:    [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CALLER_FUNC]] to $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+// FIVE:    [[THUNK:%.*]] = function_ref @$sScA_pSgIegHgIL_IegH_TRScMTU : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
+// FIVE:    [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[TTFI]]) :
+// SIX:     [[THUNK:%.*]] = function_ref @$sScA_pSgIetHgIL_IeghH_TRScMTU : $@convention(thin) @Sendable @async (@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
+// SIX:     [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[GLOBAL_CALLER_FUNC]]) :
+// CHECK:   [[V1:%.*]] = move_value [lexical] [var_decl] [[PA]]
+// CHECK:   [[V1_B:%.*]] = begin_borrow [[V1]]
+// CHECK:   [[V1_B_C:%.*]] = copy_value [[V1_B]]
+// CHECK:   [[V1_B_C_B:%.*]] = begin_borrow [[V1_B_C]]
+// FIVE:    apply [[V1_B_C_B]]() : $@async @callee_guaranteed () -> ()
+// SIX:     apply [[V1_B_C_B]]() : $@Sendable @async @callee_guaranteed () -> ()
+
+// CHECK:   [[GLOBAL_CONCURRENT_FUNC:%.*]] = function_ref @$s21attr_execution_silgen20globalConcurrentFuncyyYaF : $@convention(thin) @async () -> ()
+// CHECK:   [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CONCURRENT_FUNC]]
+// FIVE:    [[V2:%.*]] = move_value [lexical] [var_decl] [[TTFI]]
+// SIX:     [[CVT:%.*]] = convert_function [[TTFI]] to $@Sendable @async @callee_guaranteed () -> ()
+// SIX:     [[V2:%.*]] = move_value [lexical] [var_decl] [[CVT]]
+// CHECK:   [[V2_B:%.*]] = begin_borrow [[V2]]
+// CHECK:   [[V2_B_C:%.*]] = copy_value [[V2_B]]
+// CHECK:   [[V2_B_C_B:%.*]] = begin_borrow [[V2_B_C]]
+// CHECK:   apply [[V2_B_C_B]]()
+
+// FIVE:   [[X_C:%.*]] = copy_value [[X]]
+// FIVE:   [[V3:%.*]] = move_value [lexical] [var_decl] [[X_C]]
+// FIVE:   [[V3_B:%.*]] = begin_borrow [[V3]]
+// FIVE:   [[V3_B_C:%.*]] = copy_value [[V3_B]]
+// FIVE:   [[V3_B_C_B:%.*]] = begin_borrow [[V3_B_C]]
+// FIVE:   apply [[V3_B_C_B]]()
+
+// FIVE:   [[Y_C:%.*]] = copy_value [[Y]]
+// FIVE:   [[THUNK:%.*]] = function_ref @$sScA_pSgIegHgIL_IegH_TRScMTU : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
+// FIVE:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
+// FIVE:   [[V4:%.*]] = move_value [lexical] [var_decl] [[PA]]
+// FIVE:   [[V4_B:%.*]] = begin_borrow [[V4]]
+// FIVE:   [[V4_B_C:%.*]] = copy_value [[V4_B]]
+// FIVE:   [[V4_B_C_B:%.*]] = begin_borrow [[V4_B_C]]
+// FIVE:   apply [[V4_B_C_B]]()
+
+// CHECK: } // end sil function '$s21attr_execution_silgen22globalActorConversionsyyyyYac_yyYaYCctYaF'
+
+// SIX-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSgIetHgIL_IeghH_TRScMTU : $@convention(thin) @Sendable @async (@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
+// SIX: bb0([[FUNC:%.*]] : $@convention(thin) @async (@sil_isolated
+// SIX:   [[ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// SIX:   [[E:%.*]] = init_existential_ref [[ACTOR]] : $MainActor : $MainActor, $any Actor
+// SIX:   [[E_OPT:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[E]]
+// SIX:   hop_to_executor [[E_OPT]]
+// SIX:   apply [[FUNC]]([[E_OPT]]) : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+// SIX: } // end sil function '$sScA_pSgIetHgIL_IeghH_TRScMTU'
+
+func globalActorConversions(_ x: @escaping @concurrent () async -> (),
+                            _ y: nonisolated(nonsending) @escaping () async -> ()) async {
+  let v1: @MainActor () async -> Void = globalCallerFunc
+  await v1()
+  let v2: @MainActor () async -> Void = globalConcurrentFunc
+  await v2()
+
+  // These are invalid in swift 6 since x is not Sendable and this @MainActor
+  // is.
+#if SWIFT_FIVE
+  let v3: @MainActor () async -> Void = x
+  await v3()
+  let v4: @MainActor () async -> Void = y
+  await v4()
+#endif
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen23globalActorConversions2yyyAA13SendableKlassCYac_yADYaYCctYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@guaranteed SendableKlass) -> (), @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> () {
+// CHECK: bb0([[X:%.*]] : @guaranteed $@async @callee_guaranteed (@guaranteed SendableKlass) -> (), [[Y:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()):
+// CHECK:   [[GLOBAL_CALLER_FUNC:%.*]] = function_ref @$s21attr_execution_silgen29globalCallerFuncSendableKlassyyAA0gH0CYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()
+// FIVE:    [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CALLER_FUNC]] to $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()
+// FIVE:    [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCIegHgILg_ADIegHg_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> ()
+// FIVE:    [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[TTFI]]) :
+// SIX:     [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCIetHgILg_ADIeghHg_TRScMTU : $@convention(thin) @Sendable @async (@guaranteed SendableKlass, @convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> ()
+// SIX:     [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[GLOBAL_CALLER_FUNC]]) :
+// CHECK:   [[V1:%.*]] = move_value [lexical] [var_decl] [[PA]]
+// CHECK:   [[V1_B:%.*]] = begin_borrow [[V1]]
+// CHECK:   [[V1_B_C:%.*]] = copy_value [[V1_B]]
+// CHECK:   [[V1_B_C_B:%.*]] = begin_borrow [[V1_B_C]]
+// FIVE:    apply [[V1_B_C_B]]({{%.*}}) : $@async @callee_guaranteed (@guaranteed SendableKlass) -> ()
+// SIX:     apply [[V1_B_C_B]]({{%.*}}) : $@Sendable @async @callee_guaranteed (@guaranteed SendableKlass) -> ()
+
+// CHECK:   [[GLOBAL_CONCURRENT_FUNC:%.*]] = function_ref @$s21attr_execution_silgen33globalConcurrentFuncSendableKlassyyAA0gH0CYaF : $@convention(thin) @async (@guaranteed SendableKlass) -> ()
+// CHECK:   [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CONCURRENT_FUNC]] to $@async @callee_guaranteed (@guaranteed SendableKlass) -> ()
+// FIVE:    [[V2:%.*]] = move_value [lexical] [var_decl] [[TTFI]]
+// SIX:     [[CVT:%.*]] = convert_function [[TTFI]] to $@Sendable @async @callee_guaranteed (@guaranteed SendableKlass) -> ()
+// SIX:     [[V2:%.*]] = move_value [lexical] [var_decl] [[CVT]]
+// CHECK:   [[V2_B:%.*]] = begin_borrow [[V2]]
+// CHECK:   [[V2_B_C:%.*]] = copy_value [[V2_B]]
+// CHECK:   [[V2_B_C_B:%.*]] = begin_borrow [[V2_B_C]]
+// CHECK:   apply [[V2_B_C_B]]({{%.*}})
+
+// FIVE:   [[X_C:%.*]] = copy_value [[X]]
+// FIVE:   [[V3:%.*]] = move_value [lexical] [var_decl] [[X_C]]
+// FIVE:   [[V3_B:%.*]] = begin_borrow [[V3]]
+// FIVE:   [[V3_B_C:%.*]] = copy_value [[V3_B]]
+// FIVE:   [[V3_B_C_B:%.*]] = begin_borrow [[V3_B_C]]
+// FIVE:   apply [[V3_B_C_B]]({{%.*}})
+
+// FIVE:   [[Y_C:%.*]] = copy_value [[Y]]
+// FIVE:   [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCIegHgILg_ADIegHg_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> ()
+// FIVE:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
+// FIVE:   [[V4:%.*]] = move_value [lexical] [var_decl] [[PA]]
+// FIVE:   [[V4_B:%.*]] = begin_borrow [[V4]]
+// FIVE:   [[V4_B_C:%.*]] = copy_value [[V4_B]]
+// FIVE:   [[V4_B_C_B:%.*]] = begin_borrow [[V4_B_C]]
+// FIVE:   apply [[V4_B_C_B]]({{%.*}})
+
+// CHECK: } // end sil function '$s21attr_execution_silgen23globalActorConversions2yyyAA13SendableKlassCYac_yADYaYCctYaF'
+
+// FIVE-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSg21attr_execution_silgen13SendableKlassCIegHgILg_ADIegHg_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> () {
+// FIVE: bb0([[ARG:%.*]] : @guaranteed $SendableKlass, [[FUNC:%.*]] : @guaranteed
+// FIVE:   [[ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// FIVE:   [[E:%.*]] = init_existential_ref [[ACTOR]] : $MainActor : $MainActor, $any Actor
+// FIVE:   [[E_OPT:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[E]]
+// FIVE:   hop_to_executor [[E_OPT]]
+// FIVE:   apply [[FUNC]]([[E_OPT]], [[ARG]])
+// FIVE: } // end sil function '$sScA_pSg21attr_execution_silgen13SendableKlassCIegHgILg_ADIegHg_TRScMTU
+
+// SIX-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSg21attr_execution_silgen13SendableKlassCIetHgILg_ADIeghHg_TRScMTU : $@convention(thin) @Sendable @async (@guaranteed SendableKlass, @convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> () {
+// SIX: bb0([[ARG:%.*]] : @guaranteed $SendableKlass, [[FUNC:%.*]] : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()):
+// SIX:   [[ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// SIX:   [[E:%.*]] = init_existential_ref [[ACTOR]] : $MainActor : $MainActor, $any Actor
+// SIX:   [[E_OPT:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[E]]
+// SIX:   hop_to_executor [[E_OPT]]
+// SIX:   apply [[FUNC]]([[E_OPT]], [[ARG]])
+// SIX: // end sil function '$sScA_pSg21attr_execution_silgen13SendableKlassCIetHgILg_ADIeghHg_TRScMTU'
+
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSg21attr_execution_silgen13SendableKlassCIegHgILg_ADIegHg_TR : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> () {
+// CHECK: bb0([[ARG:%.*]] : @guaranteed $SendableKlass, [[FUNC:%.*]] : @guaranteed
+// CHECK:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK:   hop_to_executor [[ACTOR]]
+// CHECK:   apply [[FUNC]]([[ACTOR]], [[ARG]])
+// CHECK: } // end sil function '$sScA_pSg21attr_execution_silgen13SendableKlassCIegHgILg_ADIegHg_TR'
+func globalActorConversions2(_ x: @escaping @concurrent (SendableKlass) async -> (),
+                             _ y: nonisolated(nonsending) @escaping (SendableKlass) async -> ()) async {
+  let v1: @MainActor (SendableKlass) async -> Void = globalCallerFuncSendableKlass
+  await v1(SendableKlass())
+  let v2: @MainActor (SendableKlass) async -> Void = globalConcurrentFuncSendableKlass
+  await v2(SendableKlass())
+#if SWIFT_FIVE
+  let v3: @MainActor (SendableKlass) async -> Void = x
+  await v3(SendableKlass())
+  let v4: @MainActor (SendableKlass) async -> Void = y
+  await v4(SendableKlass())
+#endif
+  let v5: @concurrent (SendableKlass) async -> Void = y
+  await v5(SendableKlass())
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen23globalActorConversions3yyAA13SendableKlassCADYac_A2DYaYCctYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@guaranteed SendableKlass) -> @owned SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> () {
+// CHECK: bb0([[X:%.*]] : @guaranteed $@async @callee_guaranteed (@guaranteed SendableKlass) -> @owned SendableKlass, [[Y:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass):
+// CHECK:   [[GLOBAL_CALLER_FUNC:%.*]] = function_ref @$s21attr_execution_silgen29globalCallerFuncSendableKlassyAA0gH0CADYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass
+// FIVE:    [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CALLER_FUNC]] to $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass
+// FIVE:    [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHgILgo_A2DIegHgo_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass
+// FIVE:    [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[TTFI]])
+// SIX:     [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCADIetHgILgo_A2DIeghHgo_TRScMTU : $@convention(thin) @Sendable @async (@guaranteed SendableKlass, @convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass
+// SIX:     [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[GLOBAL_CALLER_FUNC]])
+// CHECK:   [[V1:%.*]] = move_value [lexical] [var_decl] [[PA]]
+// CHECK:   [[V1_B:%.*]] = begin_borrow [[V1]]
+// CHECK:   [[V1_B_C:%.*]] = copy_value [[V1_B]]
+// CHECK:   [[V1_B_C_B:%.*]] = begin_borrow [[V1_B_C]]
+// CHECK:   apply [[V1_B_C_B]]({{%.*}})
+
+// CHECK:   [[GLOBAL_CONCURRENT_FUNC:%.*]] = function_ref @$s21attr_execution_silgen33globalConcurrentFuncSendableKlassyAA0gH0CADYaF : $@convention(thin) @async (@guaranteed SendableKlass) -> @owned SendableKlass
+// CHECK:   [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CONCURRENT_FUNC]] to $@async @callee_guaranteed (@guaranteed SendableKlass) -> @owned SendableKlass
+// FIVE:    [[V2:%.*]] = move_value [lexical] [var_decl] [[TTFI]]
+// SIX:     [[CVT:%.*]] = convert_function [[TTFI]] to $@Sendable @async @callee_guaranteed (@guaranteed SendableKlass) -> @owned SendableKlass
+// SIX:     [[V2:%.*]] = move_value [lexical] [var_decl] [[CVT]]
+// CHECK:   [[V2_B:%.*]] = begin_borrow [[V2]]
+// CHECK:   [[V2_B_C:%.*]] = copy_value [[V2_B]]
+// CHECK:   [[V2_B_C_B:%.*]] = begin_borrow [[V2_B_C]]
+// CHECK:   apply [[V2_B_C_B]]({{%.*}})
+
+// FIVE:   [[X_C:%.*]] = copy_value [[X]]
+// FIVE:   [[V3:%.*]] = move_value [lexical] [var_decl] [[X_C]]
+// FIVE:   [[V3_B:%.*]] = begin_borrow [[V3]]
+// FIVE:   [[V3_B_C:%.*]] = copy_value [[V3_B]]
+// FIVE:   [[V3_B_C_B:%.*]] = begin_borrow [[V3_B_C]]
+// FIVE:   apply [[V3_B_C_B]]({{%.*}})
+
+// FIVE:   [[Y_C:%.*]] = copy_value [[Y]]
+// FIVE:   [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHgILgo_A2DIegHgo_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass
+// FIVE:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
+// FIVE:   [[V4:%.*]] = move_value [lexical] [var_decl] [[PA]]
+// FIVE:   [[V4_B:%.*]] = begin_borrow [[V4]]
+// FIVE:   [[V4_B_C:%.*]] = copy_value [[V4_B]]
+// FIVE:   [[V4_B_C_B:%.*]] = begin_borrow [[V4_B_C]]
+// FIVE:   apply [[V4_B_C_B]]({{%.*}})
+
+// CHECK:  [[Y_C:%.*]] = copy_value [[Y]]
+// CHECK:  [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHgILgo_A2DIegHgo_TR : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass
+// CHECK:  [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
+// CHECK:  [[V5:%.*]] = move_value [lexical] [var_decl] [[PA]]
+// CHECK: } // end sil function '$s21attr_execution_silgen23globalActorConversions3yyAA13SendableKlassCADYac_A2DYaYCctYaF'
+
+// FIVE-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHgILgo_A2DIegHgo_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass {
+// FIVE: bb0([[ARG:%.*]] : @guaranteed $SendableKlass, [[FUNC:%.*]] : @guaranteed
+// FIVE:   [[ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// FIVE:   [[E:%.*]] = init_existential_ref [[ACTOR]] : $MainActor : $MainActor, $any Actor
+// FIVE:   [[E_OPT:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[E]]
+// FIVE:   hop_to_executor [[E_OPT]]
+// FIVE:   apply [[FUNC]]([[E_OPT]], [[ARG]])
+// FIVE: } // end sil function '$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHgILgo_A2DIegHgo_TRScMTU'
+
+// SIX-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSg21attr_execution_silgen13SendableKlassCADIetHgILgo_A2DIeghHgo_TRScMTU : $@convention(thin) @Sendable @async (@guaranteed SendableKlass, @convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass {
+// SIX: bb0([[ARG:%.*]] : @guaranteed $SendableKlass, [[FUNC:%.*]] : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass):
+// SIX:   [[ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// SIX:   [[E:%.*]] = init_existential_ref [[ACTOR]] : $MainActor : $MainActor, $any Actor
+// SIX:   [[E_OPT:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[E]]
+// SIX:   hop_to_executor [[E_OPT]]
+// SIX:   apply [[FUNC]]([[E_OPT]], [[ARG]])
+// SIX: } // end sil function '$sScA_pSg21attr_execution_silgen13SendableKlassCADIetHgILgo_A2DIeghHgo_TRScMTU'
+
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHgILgo_A2DIegHgo_TR : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass {
+// CHECK: bb0([[ARG:%.*]] : @guaranteed $SendableKlass, [[FUNC:%.*]] : @guarantee
+// CHECK: [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK: hop_to_executor [[ACTOR]]
+// CHECK: } // end sil function '$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHgILgo_A2DIegHgo_TR'
+func globalActorConversions3(_ x: @escaping @concurrent (SendableKlass) async -> SendableKlass,
+                             _ y: nonisolated(nonsending) @escaping (SendableKlass) async -> SendableKlass) async {
+  let v1: @MainActor (SendableKlass) async -> SendableKlass = globalCallerFuncSendableKlass
+  _ = await v1(SendableKlass())
+  let v2: @MainActor (SendableKlass) async -> SendableKlass = globalConcurrentFuncSendableKlass
+  _ = await v2(SendableKlass())
+#if SWIFT_FIVE
+  let v3: @MainActor (SendableKlass) async -> SendableKlass = x
+  _ = await v3(SendableKlass())
+  let v4: @MainActor (SendableKlass) async -> SendableKlass = y
+  _ = await v4(SendableKlass())
+#endif
+  let v5: @concurrent (SendableKlass) async -> SendableKlass = y
+  _ = await v5(SendableKlass())
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen26conversionsFromSyncToAsyncyyyAA16NonSendableKlassCYbc_yAA0jK0CYbScMYcctYaF : $@convention(thin) @async (@guaranteed @Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> (), @guaranteed @Sendable @callee_guaranteed (@guaranteed SendableKlass) -> ()) -> ()
+// CHECK: bb0([[X:%.*]] : @guaranteed $@Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> (), [[Y:%.*]] : @guaranteed $@Sendable @callee_guaranteed (@guaranteed SendableKlass) -> ()):
+
+// CHECK:   [[X_C:%.*]] = copy_value [[X]]
+// CHECK:   [[THUNK:%.*]] = function_ref @$s21attr_execution_silgen16NonSendableKlassCIeghg_ScA_pSgACIegHgILg_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed NonSendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> ()) -> ()
+// CHECK:   [[PAI:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[X_C]])
+
+// CHECK:   [[Y_C:%.*]] = copy_value [[Y]]
+// CHECK:   [[THUNK:%.*]] = function_ref @$s21attr_execution_silgen13SendableKlassCIeghg_ScA_pSgACIegHgILg_TRScMTU : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed SendableKlass) -> ()) -> ()
+// CHECK:   [[PAI:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
+
+// CHECK:   [[Y_C:%.*]] = copy_value [[Y]]
+// CHECK:   [[THUNK:%.*]] = function_ref @$s21attr_execution_silgen13SendableKlassCIeghg_ACIegHg_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed SendableKlass) -> ()) -> ()
+// CHECK:   [[PAI:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
+
+// CHECK: } // end sil function '$s21attr_execution_silgen26conversionsFromSyncToAsyncyyyAA16NonSendableKlassCYbc_yAA0jK0CYbScMYcctYaF'
+
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$s21attr_execution_silgen16NonSendableKlassCIeghg_ScA_pSgACIegHgILg_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed NonSendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> ()) -> () {
+// CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>
+// CHECK: apply {{%.*}}({{%.*}}) : $@Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> ()
+// CHECK: hop_to_executor [[ACTOR]]
+// CHECK: } // end sil function '$s21attr_execution_silgen16NonSendableKlassCIeghg_ScA_pSgACIegHgILg_TR'
+
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$s21attr_execution_silgen13SendableKlassCIeghg_ScA_pSgACIegHgILg_TRScMTU : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed SendableKlass) -> ()) -> () {
+// CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : @guaranteed $SendableKlass, [[FUNC:%.*]] : @guaranteed $@Sendable @callee_guaranteed
+// CHECK:   [[MAIN_ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// CHECK:   [[MAIN_ACTOR_B:%.*]] = begin_borrow [[MAIN_ACTOR]]
+// CHECK:   hop_to_executor [[MAIN_ACTOR_B]]
+// CHECK:   apply [[FUNC]]([[ARG]])
+// CHECK:   hop_to_executor [[ACTOR]]
+// CHECK: } // end sil function '$s21attr_execution_silgen13SendableKlassCIeghg_ScA_pSgACIegHgILg_TRScMTU'
+
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$s21attr_execution_silgen13SendableKlassCIeghg_ACIegHg_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed SendableKlass) -> ()) -> () {
+// CHECK: bb0([[ARG:%.*]] : @guaranteed $SendableKlass, [[FUNC:%.*]] : @guaranteed $@Sendable @callee_guaranteed (@guaranteed SendableKlass) -> ()):
+// CHECK:   [[MAIN_ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// CHECK:   [[MAIN_ACTOR_B:%.*]] = begin_borrow [[MAIN_ACTOR]]
+// CHECK:   hop_to_executor [[MAIN_ACTOR_B]]
+// CHECK-NOT: hop_to_executor
+// CHECK:   apply [[FUNC]]([[ARG]])
+// CHECK: } // end sil function '$s21attr_execution_silgen13SendableKlassCIeghg_ACIegHg_TRScMTU'
+
+func conversionsFromSyncToAsync(_ x: @escaping @Sendable (NonSendableKlass) -> Void,
+                                _ y: @escaping @MainActor @Sendable (SendableKlass) -> Void) async {
+  let _: nonisolated(nonsending) (NonSendableKlass) async -> Void = x
+  let _: nonisolated(nonsending) (SendableKlass) async -> Void = y
+  let _: @concurrent (SendableKlass) async -> Void = y
+}
+
+func testThatClosuresAssumeIsolation(fn: inout nonisolated(nonsending) (Int) async -> Void) {
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFyyYaYCcfU_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+  // CHECK: bb0([[EXECUTOR:%.*]] : @guaranteed $Optional<any Actor>):
+  // CHECK: hop_to_executor [[EXECUTOR]]
+  let _: nonisolated(nonsending) () async -> Void = {
+    42
+  }
+
+  func testParam(_: nonisolated(nonsending) () async throws -> Void) {}
+
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFyyYaYCXEfU0_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> @error any Error {
+  // CHECK: bb0([[EXECUTOR:%.*]] : @guaranteed $Optional<any Actor>):
+  // CHECK: hop_to_executor [[EXECUTOR]]
+  // CHECK: } // end sil function '$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFyyYaYCXEfU0_'
+  testParam { 42 }
+
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFyyYaXEfU1_ : $@convention(thin) @async () -> ()
+  // CHECK: [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+  // CHECK: hop_to_executor [[GENERIC_EXECUTOR]]
+  testParam { @concurrent in 42 }
+
+  // CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sIgH_ScA_pSgs5Error_pIegHgILzo_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @noescape @async @callee_guaranteed () -> ()) -> @error any Error {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[FUNC:%.*]] : @guaranteed $@noescape @async @callee_guaranteed () -> ()):
+  // CHECK:   apply [[FUNC]]()
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$sIgH_ScA_pSgs5Error_pIegHgILzo_TR'
+
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFySiYaYCcfU2_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, Int) -> () {
+  // CHECK: bb0([[EXECUTOR:%.*]] : @guaranteed $Optional<any Actor>, %1 : $Int):
+  // CHECK: hop_to_executor [[EXECUTOR]]
+  fn = { _ in }
+
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFySiYacfU3_ : $@convention(thin) @async (Int) -> ()
+  // CHECK: [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+  // CHECK: hop_to_executor [[GENERIC_EXECUTOR]]
+  // CHECK: } // end sil function '$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFySiYacfU3_'
+
+  // CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sSiIegHy_ScA_pSgSiIegHgILy_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, Int, @guaranteed @async @callee_guaranteed (Int) -> ()) -> () {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : $Int, [[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (Int) -> ()):
+  // CHECK:  apply [[FUNC]]([[ARG]])
+  // CHECK:  hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$sSiIegHy_ScA_pSgSiIegHgILy_TR'
+  fn = { @concurrent _ in }
+}
+
+@MainActor
+func testNoIsolationTransfer() {
+  // CHECK: // Isolation: global_actor. type: MainActor
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen23testNoIsolationTransferyyF0D7ErasureL_yyyyYaYAcF : $@convention(thin) (@guaranteed @isolated(any) @async @callee_guaranteed () -> ()) -> ()
+  func testErasure(@_inheritActorContext _: @escaping @isolated(any) () async -> Void) {}
+
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen23testNoIsolationTransferyyFyyYacfU_ : $@convention(thin) @async (@guaranteed Optional<any Actor>) -> ()
+  // CHECK: [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+  // CHECK: hop_to_executor [[GENERIC_EXECUTOR]]
+  testErasure { @concurrent in }
+}
+
+func testClosuresDontAssumeGlobalActorWithMarkedAsConcurrent() {
+  func test(_ fn: @MainActor () async -> Void) {}
+
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen55testClosuresDontAssumeGlobalActorWithMarkedAsConcurrentyyFyyYaYbXEfU_
+  // CHECK: [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+  // CHECK-NEXT: hop_to_executor [[GENERIC_EXECUTOR]]
+  // CHECK: } // end sil function '$s21attr_execution_silgen55testClosuresDontAssumeGlobalActorWithMarkedAsConcurrentyyFyyYaYbXEfU_'
+  test { @Sendable @concurrent in
+  }
+}
+
+nonisolated(nonsending)
+public func takesCallerIsolatedThrowingFunction<T>(
+  _ operation: nonisolated(nonsending) () async throws -> T
+) async rethrows -> T {
+  try await operation()
+}
+
+func observe() {}
+
+// Test that we emit closures with nonisolated(nonsending) isolation without
+// introducing an intermediate @concurrent closure function.
+func testConvertToThrowing(isolation: isolated (any Actor)? = #isolation) async {
+  // CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen21testConvertToThrowing9isolationyScA_pSgYi_tYaF :
+  // CHECK:         [[ACTOR_COPY:%.*]] = copy_value %0
+  // CHECK-NEXT:    [[ACTOR_BORROW:%.*]] = begin_borrow [[ACTOR_COPY]]
+  // CHECK-NEXT:    hop_to_executor [[ACTOR_BORROW]]
+  // CHECK:         [[CLOSURE:%.*]] = function_ref @$s21attr_execution_silgen21testConvertToThrowing9isolationyScA_pSgYi_tYaFyyYaYCXEfU_ :
+  // CHECK-NEXT:    [[CLOSURE_VALUE:%.*]] = thin_to_thick_function [[CLOSURE]] to
+  // CHECK-NEXT:    // function_ref
+  // CHECK-NEXT:    [[FN:%.*]] = function_ref
+  // CHECK-NEXT:    try_apply [[FN]]<()>({{%.*}}, {{%.*}}, [[CLOSURE_VALUE]]) {{.*}}, normal bb1, error bb2
+  // CHECK:       bb1(
+  //   This hop is unnecessary because nonisolated(nonsending) should
+  //   preserve isolation on return.
+  // CHECK-NEXT:    hop_to_executor [[ACTOR_BORROW]]
+
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen21testConvertToThrowing9isolationyScA_pSgYi_tYaFyyYaYCXEfU_ : $@convention(thin) @async @substituted <τ_0_0> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> (@out τ_0_0, @error any Error) for <()>
+  // CHECK:      bb0(
+  // CHECK-NEXT:   debug_value
+  //   This hop is unnecessary because nonisolated(nonsending) should
+  //   ensure isolation before call.
+  // CHECK-NEXT:   hop_to_executor %1
+  // CHECK-NEXT:   // function_ref observe()
+  // CHECK-NEXT:   [[FN:%.*]] = function_ref @$s21attr_execution_silgen7observeyyF :
+  // CHECK-NEXT:   apply [[FN]]()
+
+  await takesCallerIsolatedThrowingFunction {
+    observe()
+  }
+}
+
+func testSendableClosureNonisolatedNonSendingInference() {
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen49testSendableClosureNonisolatedNonSendingInferenceyyFySiYaYbYCcfU_ : $@convention(thin) @Sendable @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, Int) -> ()
+  // CHECK: bb0([[EXECUTOR:%.*]] : @guaranteed $Optional<any Actor>, %1 : $Int):
+  // CHECK: hop_to_executor [[EXECUTOR]]
+  // CHECK: // end sil function '$s21attr_execution_silgen49testSendableClosureNonisolatedNonSendingInferenceyyFySiYaYbYCcfU_'
+  let _: nonisolated(nonsending) @Sendable (Int) async -> Void = { _ in }
+
+  // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen49testSendableClosureNonisolatedNonSendingInferenceyyFyS2SYaKYCcYaYbYCcfU0_ : $@convention(thin) @Sendable @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error)) -> @error any Error
+  // CHECK: bb0([[EXECUTOR:%.*]] : @guaranteed $Optional<any Actor>, %1 : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error)):
+  // CHECK: hop_to_executor [[EXECUTOR]]
+  // CHECK: // end sil function '$s21attr_execution_silgen49testSendableClosureNonisolatedNonSendingInferenceyyFyS2SYaKYCcYaYbYCcfU0_'
+  let _: nonisolated(nonsending) @Sendable (
+    nonisolated(nonsending) @escaping (String) async throws -> String
+  ) async throws -> Void = { _ in }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen014testSendableToE35ConversionWithNonisilatedNonsendingyyF : $@convention(thin) () -> ()
+// CHECK: [[TEST_REF:%.*]] = function_ref @$s21attr_execution_silgen014testSendableToE35ConversionWithNonisilatedNonsendingyyF0D0L_7closureyS2SYaKYCc_tYaYbKF : $@convention(thin) @Sendable @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error)) -> @error any Error
+// CHECK: // end sil function '$s21attr_execution_silgen014testSendableToE35ConversionWithNonisilatedNonsendingyyF'
+func testSendableToSendableConversionWithNonisilatedNonsending() {
+  @Sendable nonisolated(nonsending) func test(
+    closure: nonisolated(nonsending) @escaping (String) async throws -> String
+  ) async throws {
+  }
+
+  let _: nonisolated(nonsending) @Sendable (
+    nonisolated(nonsending) @escaping (String) async throws -> String
+  ) async throws -> Void = test
+}
diff --git a/test/Concurrency/attr_execution/cross_module.swift b/test/Concurrency/attr_execution/cross_module.swift
new file mode 100644
index 0000000000000..d937175f92912
--- /dev/null
+++ b/test/Concurrency/attr_execution/cross_module.swift
@@ -0,0 +1,30 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+/// Build the library A
+// RUN: %target-swift-frontend -emit-module %t/src/A.swift \
+// RUN:   -module-name A -swift-version 6 -enable-library-evolution \
+// RUN:   -emit-module-path %t/A.swiftmodule \
+// RUN:   -emit-module-interface-path %t/A.swiftinterface
+
+// Build the client using module
+// RUN: %target-swift-emit-sil -verify -module-name Client -I %t %t/src/Client.swift
+
+// RUN: rm %t/A.swiftmodule
+
+// Re-build the client using interface
+// RUN: %target-swift-emit-sil -verify -module-name Client -I %t %t/src/Client.swift
+
+//--- A.swift
+@MainActor
+public final class Test {
+  public func test(_: @escaping @Sendable @MainActor () -> Void) {}
+}
+
+//--- Client.swift
+import A
+
+@MainActor
+func test(t: Test, fn: @escaping @Sendable @MainActor () -> Void) {
+  t.test(fn) // Ok
+}
diff --git a/test/Concurrency/attr_execution/initializer.swift b/test/Concurrency/attr_execution/initializer.swift
new file mode 100644
index 0000000000000..274492c95d453
--- /dev/null
+++ b/test/Concurrency/attr_execution/initializer.swift
@@ -0,0 +1,176 @@
+// RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple -emit-silgen -o - -strict-concurrency=complete -enable-upcoming-feature NonisolatedNonsendingByDefault %s | %FileCheck --implicit-check-not=hop_to_executor %s
+
+// REQUIRES: concurrency
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+// This file contains tests specifically for async initializers that do not
+// include type checker errors so we can test the SIL part of the pipeline. Put type checker errors into
+// async_initializer.swift.
+
+// CHECK-LABEL: sil hidden [ossa] @$s11initializer1fyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>):
+// CHECK:  hop_to_executor [[ACTOR]]
+// CHECK: } // end sil function '$s11initializer1fyyYaF'
+func f() async {}
+func g() {}
+
+class Fruit {
+  // Fruit.__allocating_init()
+  // Isolation: caller_isolation_inheriting
+  // CHECK-LABEL: sil hidden [exact_self_class] [ossa] @$s11initializer5FruitCACyYacfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thick Fruit.Type) -> @owned Fruit {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s11initializer5FruitCACyYacfC'
+
+  // Fruit.init()
+  // Isolation: caller_isolation_inheriting
+  // CHECK-LABEL: sil hidden [ossa] @$s11initializer5FruitCACyYacfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @owned Fruit) -> @owned Fruit {
+  // CHECK: bb0([[ARG:%.*]] : @guaranteed $Optional<any Actor>,
+  // CHECK:   hop_to_executor [[ARG]]
+  // CHECK: } // end sil function '$s11initializer5FruitCACyYacfc'
+  init() async {}
+
+  // CHECK-LABEL: sil hidden [exact_self_class] [ossa] @$s11initializer5FruitC4nameACSS_tcfC : $@convention(method) (@owned String, @thick Fruit.Type) -> @owned Fruit {
+  // CHECK: } // end sil function '$s11initializer5FruitC4nameACSS_tcfC'
+
+  // CHECK-LABEL: sil hidden [ossa] @$s11initializer5FruitC4nameACSS_tcfc : $@convention(method) (@owned String, @owned Fruit) -> @owned Fruit {
+  // CHECK: } // end sil function '$s11initializer5FruitC4nameACSS_tcfc'
+  init(name: String) {}
+}
+
+class Banana: Fruit {
+  // TODO: Make this not async. We currently miscompile if this is sync.
+  //
+  // class Fruit {
+  //   required init() async {}
+  //   init(name: String) {}
+  // }
+  // 
+  // class Banana: Fruit {
+  //   override required init() {
+  //     super.init(name: "banana")
+  //   }
+  // }
+  // 
+  // func test(_ x: Fruit.Type) async {
+  //   await print(x.init())
+  // }
+  // 
+  // await test(Banana.self)
+
+  // Banana.__allocating_init()
+  // Isolation: caller_isolation_inheriting
+  // CHECK-LABEL: sil hidden [exact_self_class] [ossa] @$s11initializer6BananaCACyYacfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thick Banana.Type) -> @owned Banana {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s11initializer6BananaCACyYacfC'
+
+  // Banana.init()
+  // Isolation: caller_isolation_inheriting
+  // CHECK-LABEL: sil hidden [ossa] @$s11initializer6BananaCACyYacfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @owned Banana) -> @owned Banana {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s11initializer6BananaCACyYacfc'
+  override init() async {
+    super.init(name: "banana")
+  }
+}
+
+class MyType {
+  // MyType.__allocating_init(_:)
+  // Isolation: caller_isolation_inheriting
+  //
+  // CHECK-LABEL: sil hidden [exact_self_class] [ossa] @$s11initializer6MyTypeCyACyyYaYCXEYacfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> (), @thick MyType.Type) -> @owned MyType {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : @guaranteed $@noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s11initializer6MyTypeCyACyyYaYCXEYacfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> (), @owned MyType) -> @owned MyType
+  // CHECK:   apply [[FUNC]]([[ACTOR]], [[ARG]], {{%.*}}) :
+  // CHECK: } // end sil function '$s11initializer6MyTypeCyACyyYaYCXEYacfC'
+
+  // MyType.init(_:)
+  // Isolation: caller_isolation_inheriting
+  // CHECK-LABEL: sil hidden [ossa] @$s11initializer6MyTypeCyACyyYaYCXEYacfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> (), @owned MyType) -> @owned MyType {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : @guaranteed $@noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> (), [[SELF:%.*]] : @owned $MyType):
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK:   [[ARG_C:%.*]] = copy_value [[ARG]]
+  // CHECK:   [[ARG_B:%.*]] = begin_borrow [[ARG_C]]
+  // CHECK:   apply [[ARG_B]]([[ACTOR]])
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s11initializer6MyTypeCyACyyYaYCXEYacfc'
+  init(_ f: () async -> Void) reasync {
+    await f()
+  }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s11initializer4beepyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>):
+// CHECK:   hop_to_executor [[ACTOR]]
+// CHECK:   [[FUNC:%.*]] = function_ref @$s11initializer6MyTypeCyACyyYaYCXEYacfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> (), @thick MyType.Type) -> @owned MyType
+// CHECK:   apply [[FUNC]]([[ACTOR]], {{%.*}}, {{%.*}})
+// CHECK:   hop_to_executor [[ACTOR]]
+// CHECK:   hop_to_executor [[ACTOR]]
+// CHECK: } // end sil function '$s11initializer4beepyyYaF'
+func beep() async {
+  let _ = await MyType(f)
+  let _ = MyType(g)
+}
+
+// thunk for @escaping @callee_guaranteed () -> ()
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sIeg_ScA_pSgIegHgIL_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @callee_guaranteed () -> ()) -> () {
+// CHECK: hop_to_executor
+// CHECK: } // end sil function '$sIeg_ScA_pSgIegHgIL_TR'
+
+actor A {
+  // CHECK-LABEL: sil hidden [ossa] @$s11initializer1ACACyYacfc : $@convention(method) @async (@sil_isolated @owned A) -> @owned A {
+  // CHECK: hop_to_executor
+  // CHECK: hop_to_executor
+  // CHECK: } // end sil function '$s11initializer1ACACyYacfc'
+  init() async {
+    await f()
+  }
+
+  init() {
+  }
+}
+
+protocol AsyncDefaultConstructable {
+  init() async
+}
+
+struct Location {
+  var x : Int
+  var y : Int
+  // CHECK-LABEL: sil hidden [ossa] @$s11initializer8LocationVACyYacfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thin Location.Type) -> Location {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+  // CHECK: hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s11initializer8LocationVACyYacfC'
+  init() async {
+    self.x = 0
+    self.y = 0
+  }
+}
+
+extension Location: AsyncDefaultConstructable {}
+
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s11initializer8LocationVAA25AsyncDefaultConstructableA2aDPxyYacfCTW : $@convention(witness_method: AsyncDefaultConstructable) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thick Location.Type) -> @out Location {
+// CHECK: bb0([[INDIRECT_RESULT:%.*]] : $*Location, [[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+// CHECK:   [[FUNC:%.*]] = function_ref @$s11initializer8LocationVACyYacfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thin Location.Type) -> Location
+// CHECK:   apply [[FUNC]]([[ACTOR]],
+// CHECK:   hop_to_executor [[ACTOR]]
+// CHECK: } // end sil function '$s11initializer8LocationVAA25AsyncDefaultConstructableA2aDPxyYacfCTW'
+
+// CHECK-LABEL: sil hidden [exact_self_class] [ossa] @$s11initializer12ExplicitTestCACyYaKcfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thick ExplicitTest.Type) -> (@owned ExplicitTest, @error any Error) {
+// CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+// CHECK:   hop_to_executor [[ACTOR]]
+// CHECK:   [[FUNC:%.*]] = function_ref @$s11initializer12ExplicitTestCACyYaKcfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @owned ExplicitTest) -> (@owned ExplicitTest, @error any Error)
+// CHECK:   try_apply [[FUNC]]([[ACTOR]], {{%.*}})
+// CHECK: } // end sil function '$s11initializer12ExplicitTestCACyYaKcfC'
+
+// CHECK-LABEL: sil hidden [ossa] @$s11initializer12ExplicitTestCACyYaKcfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @owned ExplicitTest) -> (@owned ExplicitTest, @error any Error) {
+// CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+// CHECK:   hop_to_executor [[ACTOR]]
+// CHECK: } // end sil function '$s11initializer12ExplicitTestCACyYaKcfc'
+class ExplicitTest {
+    nonisolated(nonsending) init() async throws {
+    }
+}
diff --git a/test/Concurrency/attr_execution/migration_mode.swift b/test/Concurrency/attr_execution/migration_mode.swift
new file mode 100644
index 0000000000000..08929d2186651
--- /dev/null
+++ b/test/Concurrency/attr_execution/migration_mode.swift
@@ -0,0 +1,395 @@
+// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple -swift-version 5 -enable-upcoming-feature NonisolatedNonsendingByDefault:migrate
+// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple -swift-version 6 -enable-upcoming-feature NonisolatedNonsendingByDefault:migrate
+
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+struct G<T> {
+  init(_: T) {}
+}
+
+@concurrent func globalAsyncF() async {}
+
+// MARK: Functions
+do {
+  func syncF() {}
+  @concurrent func concurrentAsyncF() async {}
+  nonisolated(nonsending) func nonisolatedNonsendingAsyncF() async {}
+  @MainActor func mainActorAsyncF() async {}
+  func isolatedParamAsyncF(
+    isolation: isolated (any Actor)? = #isolation
+  ) async {}
+
+  // expected-warning@+1:20 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async local function 'asyncF' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{3-3=@concurrent }}{{none}}
+  nonisolated func asyncF() async {}
+
+  struct S {
+    init(sync: ()) {}
+    @concurrent init(concurrentAsync: ()) async {}
+    nonisolated(nonsending) init(nonisolatedNonsendingAsync: ()) async {}
+    @MainActor init(mainActorAsync: ()) async {}
+    // expected-warning@+1:5 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async initializer 'init' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{5-5=@concurrent }}{{none}}
+    init(async: ()) async {}
+
+    func syncF() {}
+    @concurrent func concurrentAsyncF() async {}
+    nonisolated(nonsending) func nonisolatedNonsendingAsyncF() async {}
+    @MainActor func mainActorAsyncF() async {}
+    // expected-warning@+2:17 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async instance method 'asyncF' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{-1:5-5=@concurrent }}{{none}}
+    nonisolated
+    public func asyncF() async {}
+  }
+
+  protocol P {
+    init(sync: ())
+    @concurrent init(concurrentAsync: ()) async
+    nonisolated(nonsending) init(nonisolatedNonsendingAsync: ()) async
+    @MainActor init(mainActorAsync: ()) async
+    // expected-warning@+1:5 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async initializer 'init' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{5-5=@concurrent }}{{none}}
+    init(async: ()) async
+
+    func syncF()
+    @concurrent func concurrentAsyncF() async
+    nonisolated(nonsending) func nonisolatedNonsendingAsyncF() async
+    @MainActor func mainActorAsyncF() async
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async instance method 'asyncF' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{5-5=@concurrent }}{{none}}
+    func asyncF() async
+  }
+}
+protocol Functions {}
+extension Functions {
+  init(sync: ()) {}
+  @concurrent init(concurrentAsync: ()) async {}
+  nonisolated(nonsending) init(nonisolatedNonsendingAsync: ()) async {}
+  @MainActor init(mainActorAsync: ()) async {}
+  // expected-warning@+1:3 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async initializer 'init' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{3-3=@concurrent }}{{none}}
+  init(async: ()) async {}
+
+  func syncF() {}
+  @concurrent func concurrentAsyncF() async {}
+  nonisolated(nonsending) func nonisolatedNonsendingAsyncF() async {}
+  @MainActor func mainActorAsyncF() async {}
+  // expected-warning@+1:8 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async instance method 'asyncF' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{3-3=@concurrent }}{{none}}
+  func asyncF() async {}
+}
+
+// MARK: Storage
+do {
+  struct S {
+    var storedVar: Int
+    let storedLet: Int
+
+    var syncS: Int { get {} set {} }
+    subscript(syncS _: Int) -> Int { get {} }
+
+    @concurrent var concurrentAsyncS: Int { get async {} }
+    @concurrent subscript(concurrentAsyncS _: Int) -> Int { get async {} }
+
+    nonisolated(nonsending) var nonisolatedNonsendingAsyncS: Int { get async {} }
+    nonisolated(nonsending) subscript(nonisolatedNonsendingAsyncS _: Int) -> Int { get async {} }
+
+    @MainActor var mainActorAsyncS: Int { get async {} }
+    @MainActor subscript(mainActorAsyncS _: Int) -> Int { get async {} }
+
+    // expected-warning@+2:7 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async getter for property 'asyncS' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{-1:5-5=@concurrent }}{{none}}
+    var asyncS: Int {
+      get async {}
+    }
+    // expected-warning@+2:7 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async getter for subscript 'subscript' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{-1:5-5=@concurrent }}{{none}}
+    subscript(asyncS _: Int) -> Int {
+      get async throws {}
+    }
+  }
+
+  protocol P {
+    var syncS: Int { get }
+    subscript(syncS _: Int) -> Int { get }
+
+    @concurrent var concurrentAsyncS: Int { get async }
+    @concurrent subscript(concurrentAsyncS _: Int) -> Int { get async }
+
+    nonisolated(nonsending) var nonisolatedNonsendingAsyncS: Int { get async }
+    nonisolated(nonsending) subscript(nonisolatedNonsendingAsyncS _: Int) -> Int { get async }
+
+    @MainActor var mainActorAsyncS: Int { get async }
+    @MainActor subscript(mainActorAsyncS _: Int) -> Int { get async }
+
+    // expected-warning@+1:23 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async getter for property 'asyncS' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{5-5=@concurrent }}{{none}}
+    var asyncS: Int { get async }
+    // expected-warning@+1:39 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async getter for subscript 'subscript' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{5-5=@concurrent }}{{none}}
+    subscript(asyncS _: Int) -> Int { get async }
+  }
+}
+protocol Storage {}
+extension Storage {
+  var syncS: Int { get {} set {} }
+  subscript(syncS _: Int) -> Int { get {} }
+
+  @concurrent var concurrentAsyncS: Int { get async {} }
+  @concurrent subscript(concurrentAsyncS _: Int) -> Int { get async {} }
+
+  nonisolated(nonsending) var nonisolatedNonsendingAsyncS: Int { get async {} }
+  nonisolated(nonsending) subscript(nonisolatedNonsendingAsyncS _: Int) -> Int { get async {} }
+
+  @MainActor var mainActorAsyncS: Int { get async {} }
+  @MainActor subscript(mainActorAsyncS _: Int) -> Int { get async {} }
+
+  // expected-warning@+2:5 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async getter for property 'asyncS' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{-1:3-3=@concurrent }}{{none}}
+  var asyncS: Int {
+    get async {}
+  }
+  // expected-warning@+2:5 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async getter for subscript 'subscript' to run on the caller's actor; use '@concurrent' to preserve behavior}}{{-1:3-3=@concurrent }}{{none}}
+  subscript(asyncS _: Int) -> Int {
+    get async throws {}
+  }
+}
+
+
+// MARK: Parameters
+do {
+  enum E {
+    case esac(
+      sync: () -> Void,
+      concurrentAsync: @concurrent () async -> Void,
+      nonisolatedNonsendingAsync: nonisolated(nonsending) () async -> Void,
+      mainActorAsync: @MainActor () async -> Void,
+      // expected-warning@+1:14 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{14-14=@concurrent }}{{none}}
+      async: () async -> Void,
+      // expected-warning@+1:26 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{26-26=@concurrent }}{{none}}
+      structuralAsync: G<() async -> Void>
+    )
+  }
+
+  struct S {
+    subscript(
+      sync: () -> Void,
+      concurrentAsync: @concurrent () async -> Void,
+      nonisolatedNonsendingAsync: nonisolated(nonsending) () async -> Void,
+      mainActorAsync: @MainActor () async -> Void,
+      // expected-warning@+1:14 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{14-14=@concurrent }}{{none}}
+      async: () async -> Void,
+      // expected-warning@+1:26 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{26-26=@concurrent }}{{none}}
+      structuralAsync: G<() async -> Void>
+    ) -> Int {
+      0
+    }
+  }
+
+  func foo(
+    sync: () -> Void,
+    concurrentAsync: @concurrent () async -> Void,
+    nonisolatedNonsendingAsync: nonisolated(nonsending) () async -> Void,
+    mainActorAsync: @MainActor () async -> Void,
+    // expected-warning@+1:12 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    async: () async -> Void,
+    // expected-warning@+1:24 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{24-24=@concurrent }}{{none}}
+    structuralAsync: G<() async -> Void>
+  ) {}
+
+  let _ = { (
+    sync: () -> Void,
+    concurrentAsync: @concurrent () async -> Void,
+    nonisolatedNonsendingAsync: nonisolated(nonsending) () async -> Void,
+    mainActorAsync: @MainActor () async -> Void,
+    // expected-warning@+1:12 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    async: () async -> Void,
+    // expected-warning@+1:24 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{24-24=@concurrent }}{{none}}
+    structuralAsync: G<() async -> Void>
+  ) in
+  }
+}
+
+// MARK: Generic constraints
+do {
+  struct G<T> {
+    struct Sync where T == () -> Void {}
+    struct ConcurrentAsync where T == @concurrent () async -> Void {}
+    struct NonisolatedNonsendingAsync where T == nonisolated(nonsending) () async -> Void {}
+    struct MainActorAsync where T == @MainActor () async -> Void {}
+    // expected-warning@+1:29 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{29-29=@concurrent }}{{none}}
+    struct Async where T == () async -> Void {}
+    // expected-warning@+1:41 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{41-41=@concurrent }}{{none}}
+    struct StructuralAsync where T == G<() async -> Void> {}
+  }
+}
+
+// MARK: Variables
+do {
+  let _: () -> Void
+  let _: @concurrent () async -> Void
+  let _: nonisolated(nonsending) () async -> Void
+  let _: @MainActor () async -> Void
+  // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{10-10=@concurrent }}{{none}}
+  let _: () async -> Void
+  // expected-warning@+1:12 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+  let _: G<() async -> Void>
+}
+
+// MARK: Casts
+do {
+  let anything: Any
+
+  let _ = anything as? () -> Void
+  let _ = anything as? @concurrent () async -> Void
+  let _ = anything as? nonisolated(nonsending) () async -> Void
+  let _ = anything as? @MainActor () async -> Void
+  // expected-warning@+1:24 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{24-24=@concurrent }}{{none}}
+  let _ = anything as? () async -> Void
+  // expected-warning@+1:26 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async function type to be treated as specified to run on the caller's actor; use '@concurrent' to preserve behavior}}{{26-26=@concurrent }}{{none}}
+  let _ = anything as? G<() async -> Void>
+}
+
+// MARK: Closures
+do {
+  @concurrent
+  func asyncOnly(_: Int, _: Int) async {}
+  @concurrent
+  @Sendable
+  func asyncThrows(_: Int, _: Int) async throws {}
+
+  nonisolated
+  func test(_: @concurrent (Int, Int) async throws -> Void) {}
+
+  nonisolated
+  func nonisolatedF() {
+    let x = 0
+
+    let _ = { () -> Void in }
+
+    let _ = { @concurrent () async -> Void in }
+    let _ = { @MainActor () async -> Void in }
+
+    // Make sure all of these case compile with the fix-its applied.
+    //
+    // Cases where we add inferred effects to ensure it compiles with '@concurrent'.
+
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{34-34=async throws }}{{none}}
+    test { (a: consuming Int, b) in                               try await asyncThrows(a, b) }
+    test { @concurrent (a: consuming Int, b) async throws in      try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{29-29=async throws }}{{none}}
+    test { (a: Int, b: Int) in                                    try await asyncThrows(a, b) }
+    test { @concurrent (a: Int, b: Int) async throws in           try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{22-22=@concurrent }}{{39-39=async throws }}{{none}}
+    test { @Sendable (a: Int, b: Int) in                          try await asyncThrows(a, b) }
+    test { @Sendable @concurrent (a: Int, b: Int) async throws in try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{24-24=async throws }}{{none}}
+    test { (a: Int, b) in                                         try await asyncThrows(a, b) }
+    test { @concurrent (a: Int, b) async throws in                try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{19-19=async throws }}{{none}}
+    test { (a, b) in                                              try await asyncThrows(a, b) }
+    test { @concurrent (a, b) async throws in                     try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{19-19=async }}{{none}}
+    test { (a, b) throws -> Void in                               try await asyncThrows(a, b) }
+    test { @concurrent (a, b) async throws -> Void in             try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{23-23=async }}{{none}}
+    test { [x] (a, b) throws -> Void in                           try await asyncThrows(a, b + x) }
+    test { @concurrent [x] (a, b) async throws -> Void in         try await asyncThrows(a, b + x) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{19-19=async throws }}{{none}}
+    test { (a, b) -> Void in                                      try await asyncThrows(a, b) }
+    test { @concurrent (a, b) async throws -> Void in             try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{23-23=async throws }}{{none}}
+    test { [x] (a, b) -> Void in                                  try await asyncThrows(a, b + x) }
+    test { @concurrent [x] (a, b) async throws -> Void in         try await asyncThrows(a, b + x) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{17-17=async throws }}{{none}}
+    test { a, b -> Void in                                        try await asyncThrows(a, b) }
+    test { @concurrent a, b async throws -> Void in               try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{17-17=async throws }}{{none}}
+    test { _, _ -> Void in                                        try await asyncThrows(1, 2) }
+    test { @concurrent _, _ async throws -> Void in               try await asyncThrows(1, 2) }
+
+    // Cases that will compile with '@concurrent' as is.
+
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { (a: Int, b: Int) throws in                             try await asyncThrows(a, b) }
+    test { @concurrent (a: Int, b: Int) throws in                 try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { (a, b) throws in                                       try await asyncThrows(a, b) }
+    test { @concurrent (a, b) throws in                           try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { (_, _) throws in                                       try await asyncThrows(1, 2) }
+    test { @concurrent (_, _) throws in                           try await asyncThrows(1, 2) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { (a, b) async throws in                                 try await asyncThrows(a, b) }
+    test { @concurrent (a, b) async throws in                     try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { (a, b) async in                                        await asyncOnly(a, b) }
+    test { @concurrent (a, b) async in                            await asyncOnly(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { a, b async -> Void in                                  await asyncOnly(a, b) }
+    test { @concurrent a, b async -> Void in                      await asyncOnly(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { a, b in                                                try await asyncThrows(a, b) }
+    test { @concurrent a, b in                                    try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { a, b throws in                                         try await asyncThrows(a, b) }
+    test { @concurrent a, b throws in                             try await asyncThrows(a, b) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { a, b async in                                          await asyncOnly(a, b) }
+    test { @concurrent a, b async in                              await asyncOnly(a, b) }
+
+    // No space after 'in' necessary.
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{11-11= @concurrent in}}{{none}}
+    test {                                                        try await asyncThrows($0, $1) }
+    // No space after 'in' necessary.
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{11-11= @concurrent in}}{{none}}
+    test { try await asyncThrows($0, $1) }
+    // No space after 'in' necessary.
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{11-11= @concurrent in}}{{none}}
+    test {
+      try await asyncThrows($0, $1)
+    }
+    // Add a space after in.
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{11-11= @concurrent in }}{{none}}
+    test {try await asyncThrows($0, $1)}
+
+    test { @concurrent in                                         try await asyncThrows($0, $1) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { [x] in                                                 try await asyncThrows($0, $1 + x) }
+    test { @concurrent [x] in                                     try await asyncThrows($0, $1 + x) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{22-22=@concurrent }}{{none}}
+    test { @Sendable [x] in                                       try await asyncThrows($0, $1 + x) }
+    test { @Sendable @concurrent [x] in                           try await asyncThrows($0, $1 + x) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { [x] a, b in                                            try await asyncThrows(a, b + x) }
+    test { @concurrent [x] a, b in                                try await asyncThrows(a, b + x) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { [x] a, b async in                                      await asyncOnly(a, b + x) }
+    test { @concurrent [x] a, b async in                          await asyncOnly(a, b + x) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { [x] a, b throws in                                     try await asyncThrows(a, b + x) }
+    test { @concurrent [x] a, b throws in                         try await asyncThrows(a, b + x) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { [x] (a, b) in                                          try await asyncThrows(a, b + x) }
+    test { @concurrent [x] (a, b) in                              try await asyncThrows(a, b + x) }
+    // expected-warning@+1:10 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async closure to run on the caller's actor; use '@concurrent' to preserve behavior}}{{12-12=@concurrent }}{{none}}
+    test { [x] (a: Int, _: Int) in                                try await asyncThrows(a, x) }
+    test { @concurrent [x] (a: Int, _: Int) in                    try await asyncThrows(a, x) }
+  }
+
+  @MainActor
+  func mainActorF() {
+    let _ = { () async -> Void in }
+    let _ = {
+      await globalAsyncF()
+    }
+  }
+}
+
+// The compiler used to mark autoclosure in `MyThing` reference as "non-implicit"
+// which caused a crash in migration mode because it assumes that autoclosures
+// are always implicit.
+do {
+  struct Other {
+    init(test: Int) {}
+  }
+
+  struct S<T> {
+    typealias MyThing = Other
+    var value: T
+  }
+
+  func test(c: S<Int?>) {
+    _ = c.value.map {
+      type(of: c).MyThing(test: $0) // Ok (used to crash due to autoclosure use)
+    }
+  }
+}
diff --git a/test/Concurrency/attr_execution/migration_mode_with_interface.swift b/test/Concurrency/attr_execution/migration_mode_with_interface.swift
new file mode 100644
index 0000000000000..8fca880585648
--- /dev/null
+++ b/test/Concurrency/attr_execution/migration_mode_with_interface.swift
@@ -0,0 +1,44 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+/// Build the library
+// RUN: %target-swift-frontend -emit-module %t/src/Lib.swift \
+// RUN:   -target %target-swift-5.1-abi-triple \
+// RUN:   -module-name Lib -swift-version 5 -enable-library-evolution \
+// RUN:   -emit-module-path %t/Lib.swiftmodule \
+// RUN:   -emit-module-interface-path %t/Lib.swiftinterface
+
+// RUN: rm %t/Lib.swiftmodule
+
+// Build the client using interface
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 5 -I %t %t/src/Test.swift -enable-upcoming-feature NonisolatedNonsendingByDefault:migrate
+
+// REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+//--- Lib.swift
+public struct Counter: AsyncSequence {
+  public typealias Element = Int
+
+  public init(howHigh: Int) {
+  }
+
+  public struct AsyncIterator: AsyncIteratorProtocol {
+    public mutating func next() async -> Int? {
+      nil
+    }
+  }
+  
+  public func makeAsyncIterator() -> AsyncIterator {
+    AsyncIterator()
+  }
+}
+
+//--- Test.swift
+import Lib
+
+func count(n: Int) async {
+  // expected-warning@-1 {{feature 'NonisolatedNonsendingByDefault' will cause nonisolated async global function 'count' to run on the caller's actor; use '@concurrent' to preserve behavior}}
+  for await _ in Counter(howHigh: n) {
+  }
+}
diff --git a/test/Concurrency/attr_execution/nonisolated_cross_module_with_flag_enabled.swift b/test/Concurrency/attr_execution/nonisolated_cross_module_with_flag_enabled.swift
new file mode 100644
index 0000000000000..a9420fb751ed4
--- /dev/null
+++ b/test/Concurrency/attr_execution/nonisolated_cross_module_with_flag_enabled.swift
@@ -0,0 +1,43 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+/// Build the library A
+// RUN: %target-swift-frontend -emit-module %t/src/A.swift \
+// RUN:   -module-name A -swift-version 6 -enable-library-evolution \
+// RUN:   -enable-upcoming-feature NonisolatedNonsendingByDefault \
+// RUN:   -emit-module-path %t/A.swiftmodule \
+// RUN:   -emit-module-interface-path %t/A.swiftinterface
+
+// RUN: %target-swift-typecheck-module-from-interface(%t/A.swiftinterface) -module-name A
+
+// Build the client using module
+// RUN: %target-swift-emit-sil -verify -module-name Client -I %t %t/src/Client.swift | %FileCheck %t/src/Client.swift
+
+// RUN: rm %t/A.swiftmodule
+
+// Re-build the client using interface
+// RUN: %target-swift-emit-sil -verify -module-name Client -I %t %t/src/Client.swift | %FileCheck %t/src/Client.swift
+
+//--- A.swift
+@MainActor
+
+public final class Test {
+  public nonisolated func test() async {}
+}
+
+//--- Client.swift
+import A
+
+// CHECK-LABEL: sil hidden @$s6Client4test1ty1A4TestC_tYaF : $@convention(thin) @async (@guaranteed Test) -> ()
+// CHECK: bb0([[SELF:%.*]] : $Test):
+// CHECK:  [[MAIN_ACTOR_EXISTENTIAL:%.*]] = init_existential_ref %4 : $MainActor : $MainActor, $any Actor
+// CHECK:  [[ANY_ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[MAIN_ACTOR_EXISTENTIAL]]
+// CHECK:  [[TEST_METHOD:%.*]] = function_ref @$s1A4TestC4testyyYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed Test) -> ()
+// CHECK:  apply [[TEST_METHOD]]([[ANY_ACTOR]], [[SELF]])
+// CHECK: } // end sil function '$s6Client4test1ty1A4TestC_tYaF'
+@MainActor
+func test(t: Test) async {
+  await t.test() // Ok
+}
diff --git a/test/Concurrency/attr_execution/nonisolated_nonsending_by_default.swift b/test/Concurrency/attr_execution/nonisolated_nonsending_by_default.swift
new file mode 100644
index 0000000000000..6c240ec88f364
--- /dev/null
+++ b/test/Concurrency/attr_execution/nonisolated_nonsending_by_default.swift
@@ -0,0 +1,10 @@
+// RUN: %target-typecheck-verify-swift -swift-version 6 -enable-upcoming-feature NonisolatedNonsendingByDefault %s
+
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+func testCasts() {
+  let defaultedType = (() async -> ()).self
+  _ = defaultedType as (@concurrent () async -> ()).Type
+  // expected-error@-1 {{cannot convert value of type '(nonisolated(nonsending) () async -> ()).Type' to type '(() async -> ()).Type' in coercion}}
+  _ = defaultedType as (nonisolated(nonsending) () async -> ()).Type // Ok
+}
diff --git a/test/Concurrency/attr_execution/protocols_silgen.swift b/test/Concurrency/attr_execution/protocols_silgen.swift
new file mode 100644
index 0000000000000..e5c2dd440e751
--- /dev/null
+++ b/test/Concurrency/attr_execution/protocols_silgen.swift
@@ -0,0 +1,182 @@
+// RUN: %target-swift-emit-silgen %s -module-name attr_execution_silgen -target %target-swift-5.1-abi-triple -DSWIFT_FIVE | %FileCheck -check-prefix CHECK -check-prefix FIVE %s
+// RUN: %target-swift-emit-silgen %s -swift-version 6 -module-name attr_execution_silgen -target %target-swift-5.1-abi-triple | %FileCheck -check-prefix CHECK -check-prefix SIX %s
+
+// We codegen slightly differently for swift 5 vs swift 6, so we need to check
+// both.
+
+// REQUIRES: asserts
+// REQUIRES: concurrency
+
+protocol P {
+  nonisolated(nonsending) func callerTest() async
+  @concurrent func concurrentTest() async
+  @MainActor func mainActorTest() async
+}
+
+protocol Q {
+  nonisolated(nonsending) var test: String { get async throws }
+  nonisolated(nonsending) func fnTest() async
+}
+
+struct AllDefault : P {
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen10AllDefaultVAA1PA2aDP10callerTestyyYaFTW : $@convention(witness_method: P) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed AllDefault) -> () {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[SELF:%.*]] : $*AllDefault):
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen10AllDefaultV10callerTestyyYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, AllDefault) -> ()
+  // CHECK:   apply [[FUNC]]([[ACTOR]], [[LOAD]])
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s21attr_execution_silgen10AllDefaultVAA1PA2aDP10callerTestyyYaFTW'
+  func callerTest() async {}
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen10AllDefaultVAA1PA2aDP14concurrentTestyyYaFTW : $@convention(witness_method: P) @async (@in_guaranteed AllDefault) -> () {
+  // CHECK: bb0([[SELF:%.*]] : $*AllDefault):
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen10AllDefaultV14concurrentTestyyYaF : $@convention(method) @async (AllDefault) -> ()
+  // CHECK:   apply [[FUNC]]([[LOAD]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen10AllDefaultVAA1PA2aDP14concurrentTestyyYaFTW'
+  func concurrentTest() async {}
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen10AllDefaultVAA1PA2aDP13mainActorTestyyYaFTW : $@convention(witness_method: P) @async (@in_guaranteed AllDefault) -> () {
+  // CHECK: bb0([[SELF:%.*]] : $*AllDefault):
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen10AllDefaultV13mainActorTestyyYaF : $@convention(method) @async (AllDefault) -> ()
+  // CHECK:   apply [[FUNC]]([[LOAD]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen10AllDefaultVAA1PA2aDP13mainActorTestyyYaFTW'
+  func mainActorTest() async {}
+}
+
+struct AllCaller : P {
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen9AllCallerVAA1PA2aDP10callerTestyyYaFTW : $@convention(witness_method: P) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed AllCaller) -> () {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[SELF:%.*]] : $*AllCaller):
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen9AllCallerV10callerTestyyYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, AllCaller) -> ()
+  // CHECK:   apply [[FUNC]]([[ACTOR]], [[LOAD]])
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s21attr_execution_silgen9AllCallerVAA1PA2aDP10callerTestyyYaFTW'
+  nonisolated(nonsending) func callerTest() async {}
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen9AllCallerVAA1PA2aDP14concurrentTestyyYaFTW : $@convention(witness_method: P) @async (@in_guaranteed AllCaller) -> () {
+  // CHECK: bb0([[SELF:%.*]] : $*AllCaller):
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen9AllCallerV14concurrentTestyyYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, AllCaller) -> ()
+  // CHECK:   [[NIL:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+  // CHECK:   hop_to_executor [[NIL]]
+  // CHECK:   apply [[FUNC]]([[NIL]], [[LOAD]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen9AllCallerVAA1PA2aDP14concurrentTestyyYaFTW'
+  nonisolated(nonsending) func concurrentTest() async {}
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen9AllCallerVAA1PA2aDP13mainActorTestyyYaFTW : $@convention(witness_method: P) @async (@in_guaranteed AllCaller) -> () {
+  // CHECK: bb0([[SELF:%.*]] : $*AllCaller):
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen9AllCallerV13mainActorTestyyYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, AllCaller) -> ()
+  // CHECK:   [[MAIN_ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+  // CHECK:   [[EXIS_MAIN_ACTOR:%.*]] = init_existential_ref [[MAIN_ACTOR]]
+  // CHECK:   [[OPT_MAIN_ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[EXIS_MAIN_ACTOR]]
+  // CHECK:   hop_to_executor [[OPT_MAIN_ACTOR]]
+  // CHECK:   apply [[FUNC]]([[OPT_MAIN_ACTOR]], [[LOAD]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen9AllCallerVAA1PA2aDP13mainActorTestyyYaFTW'
+  nonisolated(nonsending) func mainActorTest() async {}
+}
+
+struct AllConcurrent : P {
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen13AllConcurrentVAA1PA2aDP10callerTestyyYaFTW : $@convention(witness_method: P) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed AllConcurrent) -> () {
+  // CHECK: bb0([[ACTOR]] : @guaranteed $Optional<any Actor>, [[SELF:%.*]] :
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen13AllConcurrentV10callerTestyyYaF : $@convention(method) @async (AllConcurrent) -> ()
+  // CHECK:   apply [[FUNC]]([[LOAD]])
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s21attr_execution_silgen13AllConcurrentVAA1PA2aDP10callerTestyyYaFTW'
+  @concurrent func callerTest() async {}
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen13AllConcurrentVAA1PA2aDP14concurrentTestyyYaFTW : $@convention(witness_method: P) @async (@in_guaranteed AllConcurrent) -> () {
+  // CHECK: bb0([[SELF:%.*]] :  
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen13AllConcurrentV14concurrentTestyyYaF : $@convention(method) @async (AllConcurrent) -> ()
+  // CHECK:   apply [[FUNC]]([[LOAD]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen13AllConcurrentVAA1PA2aDP14concurrentTestyyYaFTW'
+  @concurrent func concurrentTest() async {}
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen13AllConcurrentVAA1PA2aDP13mainActorTestyyYaFTW : $@convention(witness_method: P) @async (@in_guaranteed AllConcurrent) -> () {
+  // CHECK: bb0([[SELF:%.*]] :
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen13AllConcurrentV13mainActorTestyyYaF : $@convention(method) @async (AllConcurrent) -> ()
+  // CHECK:   apply [[FUNC]]([[LOAD]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen13AllConcurrentVAA1PA2aDP13mainActorTestyyYaFTW'
+  @concurrent func mainActorTest() async {}
+}
+
+struct AllMainActor : P {
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen12AllMainActorVAA1PA2aDP10callerTestyyYaFTW : $@convention(witness_method: P) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed AllMainActor) -> () {
+  // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[SELF:%.*]] :
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen12AllMainActorV10callerTestyyYaF : $@convention(method) @async (AllMainActor) -> ()
+  // CHECK:   apply [[FUNC]]([[LOAD]])
+  // CHECK:   hop_to_executor [[ACTOR]]
+  // CHECK: } // end sil function '$s21attr_execution_silgen12AllMainActorVAA1PA2aDP10callerTestyyYaFTW'
+  @MainActor func callerTest() async {}
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen12AllMainActorVAA1PA2aDP14concurrentTestyyYaFTW : $@convention(witness_method: P) @async (@in_guaranteed AllMainActor) -> () {
+  // CHECK: bb0([[SELF:%.*]] :
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen12AllMainActorV14concurrentTestyyYaF : $@convention(method) @async (AllMainActor) -> ()
+  // CHECK:   apply [[FUNC]]([[LOAD]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen12AllMainActorVAA1PA2aDP14concurrentTestyyYaFTW'
+  @MainActor func concurrentTest() async {}
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen12AllMainActorVAA1PA2aDP04mainF4TestyyYaFTW : $@convention(witness_method: P) @async (@in_guaranteed AllMainActor) -> () {
+  // CHECK: bb0([[SELF:%.*]] :
+  // CHECK:   [[LOAD:%.*]] = load [trivial] [[SELF]]
+  // CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen12AllMainActorV04mainF4TestyyYaF : $@convention(method) @async (AllMainActor) -> ()
+  // CHECK:   apply [[FUNC]]([[LOAD]])
+  // CHECK: } // end sil function '$s21attr_execution_silgen12AllMainActorVAA1PA2aDP04mainF4TestyyYaFTW'
+  @MainActor func mainActorTest() async {}
+}
+
+// Make sure that stored/non-async witness doesn't inherit `nonisolated(nonsending)` but thunk dismatches correctly
+
+struct TestWitnessWithStorage: Q {
+  // CHECK-LABEL: sil hidden [transparent] [ossa] @$s21attr_execution_silgen22TestWitnessWithStorageV4testSSvg : $@convention(method) (@guaranteed TestWitnessWithStorage) -> @owned String
+  // CHECK-LABEL: sil hidden [transparent] [ossa] @$s21attr_execution_silgen22TestWitnessWithStorageV4testSSvs : $@convention(method) (@owned String, @inout TestWitnessWithStorage) -> ()
+  var test: String
+
+  // CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen22TestWitnessWithStorageV02fnD0yyF : $@convention(method) (@guaranteed TestWitnessWithStorage) -> ()
+  func fnTest() {}
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen22TestWitnessWithStorageVAA1QA2aDP4testSSvgTW : $@convention(witness_method: Q) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed TestWitnessWithStorage) -> (@owned String, @error any Error)
+  // CHECK: bb0([[ISOLATION:%.*]] : @guaranteed $Optional<any Actor>, [[SELF:%.*]] : $*TestWitnessWithStorage):
+  // CHECK-NEXT: [[BORROWED_SELF:%.*]] = load_borrow [[SELF]]
+  // CHECK: [[WITNESS:%.*]] = function_ref @$s21attr_execution_silgen22TestWitnessWithStorageV4testSSvg : $@convention(method) (@guaranteed TestWitnessWithStorage) -> @owned String
+  // CHECK-NEXT: [[RESULT:%.*]] = apply [[WITNESS]]([[BORROWED_SELF]]) : $@convention(method) (@guaranteed TestWitnessWithStorage) -> @owned String
+  // CHECK-NEXT: hop_to_executor [[ISOLATION]]
+  // CHECK-NEXT: end_borrow [[BORROWED_SELF]]
+  // CHECK-NEXT: return [[RESULT]]
+  // CHECK-NEXT: } // end sil function '$s21attr_execution_silgen22TestWitnessWithStorageVAA1QA2aDP4testSSvgTW'
+
+  // CHECK: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen22TestWitnessWithStorageVAA1QA2aDP02fnD0yyYaFTW : $@convention(witness_method: Q) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed TestWitnessWithStorage) -> ()
+  // CHECK: bb0([[ISOLATION:%.*]] : @guaranteed $Optional<any Actor>, [[SELF:%.*]] : $*TestWitnessWithStorage):
+  // CHECK-NEXT: [[BORROWED_SELF]] = load_borrow [[SELF]]
+  // CHECK: [[WITNESS:%.*]] = function_ref @$s21attr_execution_silgen22TestWitnessWithStorageV02fnD0yyF : $@convention(method) (@guaranteed TestWitnessWithStorage) -> ()
+  // CHECK-NEXT: {{.*}} = apply [[WITNESS]]([[BORROWED_SELF]]) : $@convention(method) (@guaranteed TestWitnessWithStorage) -> ()
+  // CHECK-NEXT: [[RESULT:%.*]] = tuple ()
+  // CHECK-NEXT: hop_to_executor [[ISOLATION]]
+  // CHECK-NEXT: end_borrow [[BORROWED_SELF]]
+  // CHECK-NEXT: return [[RESULT]]
+  // CHECK-NEXT: } // end sil function '$s21attr_execution_silgen22TestWitnessWithStorageVAA1QA2aDP02fnD0yyYaFTW'
+}
+
+struct TestSyncWitness: Q {
+  // CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen15TestSyncWitnessV4testSSvg : $@convention(method) (TestSyncWitness) -> @owned String
+  var test: String { "" }
+
+  // CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s21attr_execution_silgen15TestSyncWitnessVAA1QA2aDP4testSSvgTW : $@convention(witness_method: Q) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed TestSyncWitness) -> (@owned String, @error any Error)
+  // CHECK: bb0([[ISOLATION:%.*]] : @guaranteed $Optional<any Actor>, [[SELF:%.*]] : $*TestSyncWitness):
+  // CHECK-NEXT: [[BORROWED_SELF:%.*]] = load [trivial] [[SELF]]
+  // CHECK: [[WITNESS:%.*]] = function_ref @$s21attr_execution_silgen15TestSyncWitnessV4testSSvg : $@convention(method) (TestSyncWitness) -> @owned String
+  // CHECK-NEXT: [[RESULT:%.*]] = apply [[WITNESS]]([[BORROWED_SELF]]) : $@convention(method) (TestSyncWitness) -> @owned String
+  // CHECK-NEXT: hop_to_executor [[ISOLATION]]
+  // CHECK-NEXT: return [[RESULT]]
+  // CHECK-NEXT: } // end sil function '$s21attr_execution_silgen15TestSyncWitnessVAA1QA2aDP4testSSvgTW'
+
+  // Tested in the `TestWitnessWithStorage`
+  func fnTest() {}
+}
diff --git a/test/Concurrency/attr_execution/silgen.swift b/test/Concurrency/attr_execution/silgen.swift
deleted file mode 100644
index 4ed0ec15f1379..0000000000000
--- a/test/Concurrency/attr_execution/silgen.swift
+++ /dev/null
@@ -1,428 +0,0 @@
-// RUN: %target-swift-emit-silgen %s -module-name attr_execution_silgen -target %target-swift-5.1-abi-triple -enable-experimental-feature ExecutionAttribute -DSWIFT_FIVE | %FileCheck -check-prefix CHECK -check-prefix FIVE %s
-// RUN: %target-swift-emit-silgen %s -swift-version 6 -module-name attr_execution_silgen -target %target-swift-5.1-abi-triple -enable-experimental-feature ExecutionAttribute | %FileCheck -check-prefix CHECK -check-prefix SIX %s
-
-// We codegen slightly differently for swift 5 vs swift 6, so we need to check
-// both.
-
-// REQUIRES: asserts
-// REQUIRES: concurrency
-// REQUIRES: swift_feature_ExecutionAttribute
-
-////////////////////////
-// MARK: Declarations //
-////////////////////////
-
-@execution(caller)
-func globalCallerFunc() async -> () {}
-
-@execution(concurrent)
-func globalConcurrentFunc() async -> () {}
-
-class NonSendableKlass {
-  init() {}
-}
-class SendableKlass : @unchecked Sendable {
-  init() {}
-}
-
-@execution(caller)
-func globalCallerFuncSendableKlass(_ x: SendableKlass) async -> () {}
-
-@execution(concurrent)
-func globalConcurrentFuncSendableKlass(_ x: SendableKlass) async -> () {}
-
-@execution(caller)
-func globalCallerFuncSendableKlass(_ x: SendableKlass) async -> SendableKlass { fatalError() }
-
-@execution(concurrent)
-func globalConcurrentFuncSendableKlass(_ x: SendableKlass) async -> SendableKlass { fatalError() }
-
-
-/////////////////
-// MARK: Tests //
-/////////////////
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen33testCallerToConcurrentNonIsolatedyyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
-// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
-// CHECK:   [[FUNC_COPY:%.*]] = copy_value [[FUNC]]
-// CHECK:   [[THUNK:%.*]] = function_ref @$sScA_pSgIegHg_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
-// CHECK:   partial_apply [callee_guaranteed] [[THUNK]]([[FUNC_COPY]])
-// CHECK: } // end sil function '$s21attr_execution_silgen33testCallerToConcurrentNonIsolatedyyyyYaYCcYaF'
-public func testCallerToConcurrentNonIsolated(_ x: @escaping @execution(caller) () async -> ()) async {
-  let y: @execution(concurrent) () async -> () = x
-  await y()
-}
-
-// This thunk is used to convert a caller to a concurrent function. So, we pass in .none as the
-// isolated parameter.
-//
-// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSgIegHg_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
-// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
-// CHECK:   [[ENUM:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
-// CHECK:   apply [[FUNC]]([[ENUM]])
-// CHECK: } // end sil function '$sScA_pSgIegHg_IegH_TR'
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen31testCallerToConcurrentMainActoryyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
-// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
-// CHECK:   [[FUNC_COPY:%.*]] = copy_value [[FUNC]]
-// CHECK:   [[THUNK:%.*]] = function_ref @$sScA_pSgIegHg_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
-// CHECK:   partial_apply [callee_guaranteed] [[THUNK]]([[FUNC_COPY]])
-// CHECK: } // end sil function '$s21attr_execution_silgen31testCallerToConcurrentMainActoryyyyYaYCcYaF'
-@MainActor
-public func testCallerToConcurrentMainActor(_ x: @escaping @execution(caller) () async -> ()) async {
-  let y: @execution(concurrent) () async -> () = x
-  await y()
-}
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen33testConcurrentToCallerNonIsolatedyyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
-// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed () -> ()):
-// CHECK:   [[FUNC_COPY:%.*]] = copy_value [[FUNC]]
-// CHECK:   [[THUNK:%.*]] = function_ref @$sIegH_ScA_pSgIegHg_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> ()
-// CHECK:   partial_apply [callee_guaranteed] [[THUNK]]([[FUNC_COPY]])
-// CHECK: } // end sil function '$s21attr_execution_silgen33testConcurrentToCallerNonIsolatedyyyyYacYaF'
-public func testConcurrentToCallerNonIsolated(_ x: @escaping @execution(concurrent) () async -> ()) async {
-  let y: @execution(caller) () async -> () = x
-  await y()
-}
-
-// This thunk has the "surface" of an @caller function, but just ignores the
-// isolated parameter and calls the concurrent funciton.
-//
-// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sIegH_ScA_pSgIegHg_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> () {
-// CHECK: bb0({{%.*}} : @guaranteed $Optional<any Actor>, [[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed () -> ()):
-// CHECK:   apply [[FUNC]]
-// CHECK: } // end sil function '$sIegH_ScA_pSgIegHg_TR'
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen42testConcurrentToCallerNonIsolatedMainActoryyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
-// CHECK: bb0([[FUNC:%.*]] :
-// CHECK:   [[FUNC_COPY:%.*]] = copy_value [[FUNC]]
-// CHECK:   [[THUNK:%.*]] = function_ref @$sIegH_ScA_pSgIegHg_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> ()
-// CHECK:   partial_apply [callee_guaranteed] [[THUNK]]([[FUNC_COPY]])
-// CHECK: } // end sil function '$s21attr_execution_silgen42testConcurrentToCallerNonIsolatedMainActoryyyyYacYaF'
-@MainActor
-public func testConcurrentToCallerNonIsolatedMainActor(_ x: @escaping @execution(concurrent) () async -> ()) async {
-  let y: @execution(caller) () async -> () = x
-  await y()
-}
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen016testConcurrentToE0yyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
-// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed () -> ()):
-// CHECK:   [[COPY:%.*]] = copy_value [[FUNC]]
-// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[COPY]]
-// CHECK:   [[BORROW_Y:%.*]] = begin_borrow [[Y]]
-// CHECK:   [[COPY_Y:%.*]] = copy_value [[BORROW_Y]]
-// CHECK:   [[BORROW_COPY_Y:%.*]] = begin_borrow [[COPY_Y]]
-// CHECK:   apply [[BORROW_COPY_Y]]()
-// CHECK:   [[FUNC:%.*]] = function_ref @$s21attr_execution_silgen20globalConcurrentFuncyyYaF : $@convention(thin) @async () -> ()
-// CHECK:   [[TTFI:%.*]] = thin_to_thick_function [[FUNC]]
-// FIVE:    [[Z:%.*]] = move_value [lexical] [var_decl] [[TTFI]]
-// SIX:     [[CVT_1:%.*]] = convert_function [[TTFI]] to $@Sendable @async
-// SIX:     [[CVT_2:%.*]] = convert_function [[CVT_1]] to $@async
-// SIX:     [[Z:%.*]] = move_value [lexical] [var_decl] [[CVT_2]]
-// CHECK:   [[BORROW_Z:%.*]] = begin_borrow [[Z]]
-// CHECK:   [[COPY_Z:%.*]] = copy_value [[BORROW_Z]]
-// CHECK:   [[BORROW_COPY_Z:%.*]] = begin_borrow [[COPY_Z]]
-// CHECK:   apply [[BORROW_COPY_Z]]()
-// CHECK: } // end sil function '$s21attr_execution_silgen016testConcurrentToE0yyyyYacYaF'
-public func testConcurrentToConcurrent(_ x: @escaping @execution(concurrent) () async -> ()) async {
-  let y: @execution(concurrent) () async -> () = x
-  await y()
-  let z: @execution(concurrent) () async -> () = globalConcurrentFunc
-  await z()
-}
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen012testCallerToE0yyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
-// CHECK: bb0([[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
-// CHECK:   [[COPY:%.*]] = copy_value [[FUNC]]
-// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[COPY]]
-// CHECK:   [[BORROW_Y:%.*]] = begin_borrow [[Y]]
-// CHECK:   [[COPY_Y:%.*]] = copy_value [[BORROW_Y]]
-// CHECK:   [[BORROW_COPY_Y:%.*]] = begin_borrow [[COPY_Y]]
-// CHECK:   apply [[BORROW_COPY_Y]]({{%.*}})
-// CHECK: } // end sil function '$s21attr_execution_silgen012testCallerToE0yyyyYaYCcYaF'
-//
-// z has a round trip issue.
-public func testCallerToCaller(_ x: @escaping @execution(caller) () async -> ()) async {
-  let y: @execution(caller) () async -> () = x
-  await y()
-  let z: @execution(caller) () async -> () = globalCallerFunc
-  await z()
-}
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen24testCallerLocalVariablesyyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
-// CHECK: bb0([[PARAM:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
-// CHECK:   [[PARAM_COPY:%.*]] = copy_value [[PARAM]]
-// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[PARAM_COPY]]
-// CHECK:   [[Y_B:%.*]] = begin_borrow [[Y]]
-// CHECK:   [[Y_B_C:%.*]] = copy_value [[Y_B]]
-// CHECK:   [[Y2:%.*]] = move_value [lexical] [var_decl] [[Y_B_C]]
-// CHECK:   [[Y2_B:%.*]] = begin_borrow [[Y2]]
-// CHECK:   [[Y2_B_C:%.*]] = copy_value [[Y2_B]]
-// CHECK:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
-// CHECK:   [[Y2_B_C_B:%.*]] = begin_borrow [[Y2_B_C]]
-// CHECK:   apply [[Y2_B_C_B]]([[ACTOR]])
-// CHECK: } // end sil function '$s21attr_execution_silgen24testCallerLocalVariablesyyyyYaYCcYaF'
-public func testCallerLocalVariables(_ x: @escaping @execution(caller) () async -> ()) async {
-  let y: @execution(caller) () async -> () = x
-  let y2: @execution(caller) () async -> () = y
-  await y2()
-}
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen28testConcurrentLocalVariablesyyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
-// CHECK:   [[PARAM_COPY:%.*]] = copy_value [[PARAM]]
-// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[PARAM_COPY]]
-// CHECK:   [[Y_B:%.*]] = begin_borrow [[Y]]
-// CHECK:   [[Y_B_C:%.*]] = copy_value [[Y_B]]
-// CHECK:   [[Y2:%.*]] = move_value [lexical] [var_decl] [[Y_B_C]]
-// CHECK:   [[Y2_B:%.*]] = begin_borrow [[Y2]]
-// CHECK:   [[Y2_B_C:%.*]] = copy_value [[Y2_B]]
-// CHECK:   [[Y2_B_C_B:%.*]] = begin_borrow [[Y2_B_C]]
-// CHECK:   apply [[Y2_B_C_B]]()
-// CHECK: } // end sil function '$s21attr_execution_silgen28testConcurrentLocalVariablesyyyyYacYaF'
-public func testConcurrentLocalVariables(_ x: @escaping @execution(concurrent) () async -> ()) async {
-  let y: @execution(concurrent) () async -> () = x
-  let y2: @execution(concurrent) () async -> () = y
-  await y2()
-}
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen34testCallerConcurrentLocalVariablesyyyyYaYCcYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
-// CHECK: bb0([[PARAM:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
-// CHECK:   [[PARAM_COPY:%.*]] = copy_value [[PARAM]]
-// CHECK:   [[THUNK_1:%.*]] = function_ref @$sScA_pSgIegHg_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
-// CHECK:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK_1]]([[PARAM_COPY]])
-// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[PA]]
-// CHECK:   [[Y_B:%.*]] = begin_borrow [[Y]]
-// CHECK:   [[Y_B_C:%.*]] = copy_value [[Y_B]]
-// CHECK:   [[THUNK_2:%.*]] = function_ref @$sIegH_ScA_pSgIegHg_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> ()
-// CHECK:   [[PA_2:%.*]] = partial_apply [callee_guaranteed] [[THUNK_2]]([[Y_B_C]])
-// CHECK: } // end sil function '$s21attr_execution_silgen34testCallerConcurrentLocalVariablesyyyyYaYCcYaF'
-public func testCallerConcurrentLocalVariables(_ x: @escaping @execution(caller) () async -> ()) async {
-  let y: @execution(concurrent) () async -> () = x
-  let y2: @execution(caller) () async -> () = y
-  await y2()
-}
-
-// CHECK-LABEL: sil [ossa] @$s21attr_execution_silgen34testConcurrentCallerLocalVariablesyyyyYacYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> ()) -> () {
-// CHECK: bb0([[PARAM:%.*]] : @guaranteed $@async @callee_guaranteed () -> ()):
-// CHECK:   [[PARAM_C:%.*]] = copy_value [[PARAM]]
-// CHECK:   [[THUNK_1:%.*]] = function_ref @$sIegH_ScA_pSgIegHg_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @async @callee_guaranteed () -> ()) -> ()
-// CHECK:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK_1]]([[PARAM_C]])
-// CHECK:   [[Y:%.*]] = move_value [lexical] [var_decl] [[PA]]
-// CHECK:   [[Y_B:%.*]] = begin_borrow [[Y]]
-// CHECK:   [[Y_B_C:%.*]] = copy_value [[Y_B]]
-// CHECK:   [[THUNK_2:%.*]] = function_ref @$sScA_pSgIegHg_IegH_TR : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
-// CHECK:   [[PA_2:%.*]] = partial_apply [callee_guaranteed] [[THUNK_2]]([[Y_B_C]])
-// CHECK: } // end sil function '$s21attr_execution_silgen34testConcurrentCallerLocalVariablesyyyyYacYaF'
-public func testConcurrentCallerLocalVariables(_ x: @escaping @execution(concurrent) () async -> ()) async {
-  let y: @execution(caller) () async -> () = x
-  let y2: @execution(concurrent) () async -> () = y
-  await y2()
-}
-
-// CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen22globalActorConversionsyyyyYac_yyYaYCctYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed () -> (), @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
-// CHECK: bb0([[X:%.*]] : @guaranteed $@async @callee_guaranteed () -> (), [[Y:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
-// CHECK:   [[GLOBAL_CALLER_FUNC:%.*]] = function_ref @$s21attr_execution_silgen16globalCallerFuncyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
-// FIVE:    [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CALLER_FUNC]] to $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
-// FIVE:    [[THUNK:%.*]] = function_ref @$sScA_pSgIegHg_IegH_TRScMTU : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
-// FIVE:    [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[TTFI]]) :
-// SIX:     [[THUNK:%.*]] = function_ref @$sScA_pSgIetHg_IeghH_TRScMTU : $@convention(thin) @Sendable @async (@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
-// SIX:     [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[GLOBAL_CALLER_FUNC]]) :
-// CHECK:   [[V1:%.*]] = move_value [lexical] [var_decl] [[PA]]
-// CHECK:   [[V1_B:%.*]] = begin_borrow [[V1]]
-// CHECK:   [[V1_B_C:%.*]] = copy_value [[V1_B]]
-// CHECK:   [[V1_B_C_B:%.*]] = begin_borrow [[V1_B_C]]
-// FIVE:    apply [[V1_B_C_B]]() : $@async @callee_guaranteed () -> ()
-// SIX:     apply [[V1_B_C_B]]() : $@Sendable @async @callee_guaranteed () -> ()
-
-// CHECK:   [[GLOBAL_CONCURRENT_FUNC:%.*]] = function_ref @$s21attr_execution_silgen20globalConcurrentFuncyyYaF : $@convention(thin) @async () -> ()
-// CHECK:   [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CONCURRENT_FUNC]]
-// FIVE:    [[V2:%.*]] = move_value [lexical] [var_decl] [[TTFI]]
-// SIX:     [[CVT:%.*]] = convert_function [[TTFI]] to $@Sendable @async @callee_guaranteed () -> ()
-// SIX:     [[V2:%.*]] = move_value [lexical] [var_decl] [[CVT]]
-// CHECK:   [[V2_B:%.*]] = begin_borrow [[V2]]
-// CHECK:   [[V2_B_C:%.*]] = copy_value [[V2_B]]
-// CHECK:   [[V2_B_C_B:%.*]] = begin_borrow [[V2_B_C]]
-// CHECK:   apply [[V2_B_C_B]]()
-
-// FIVE:   [[X_C:%.*]] = copy_value [[X]]
-// FIVE:   [[V3:%.*]] = move_value [lexical] [var_decl] [[X_C]]
-// FIVE:   [[V3_B:%.*]] = begin_borrow [[V3]]
-// FIVE:   [[V3_B_C:%.*]] = copy_value [[V3_B]]
-// FIVE:   [[V3_B_C_B:%.*]] = begin_borrow [[V3_B_C]]
-// FIVE:   apply [[V3_B_C_B]]()
-
-// FIVE:   [[Y_C:%.*]] = copy_value [[Y]]
-// FIVE:   [[THUNK:%.*]] = function_ref @$sScA_pSgIegHg_IegH_TRScMTU : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> ()
-// FIVE:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
-// FIVE:   [[V4:%.*]] = move_value [lexical] [var_decl] [[PA]]
-// FIVE:   [[V4_B:%.*]] = begin_borrow [[V4]]
-// FIVE:   [[V4_B_C:%.*]] = copy_value [[V4_B]]
-// FIVE:   [[V4_B_C_B:%.*]] = begin_borrow [[V4_B_C]]
-// FIVE:   apply [[V4_B_C_B]]()
-
-// CHECK: } // end sil function '$s21attr_execution_silgen22globalActorConversionsyyyyYac_yyYaYCctYaF'
-func globalActorConversions(_ x: @escaping @execution(concurrent) () async -> (),
-                            _ y: @escaping @execution(caller) () async -> ()) async {
-  let v1: @MainActor () async -> Void = globalCallerFunc
-  await v1()
-  let v2: @MainActor () async -> Void = globalConcurrentFunc
-  await v2()
-
-  // These are invalid in swift 6 since x is not Sendable and this @MainActor
-  // is.
-#if SWIFT_FIVE
-  let v3: @MainActor () async -> Void = x
-  await v3()
-  let v4: @MainActor () async -> Void = y
-  await v4()
-#endif
-}
-
-// CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen23globalActorConversions2yyyAA13SendableKlassCYac_yADYaYCctYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@guaranteed SendableKlass) -> (), @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> () {
-// CHECK: bb0([[X:%.*]] : @guaranteed $@async @callee_guaranteed (@guaranteed SendableKlass) -> (), [[Y:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()):
-// CHECK:   [[GLOBAL_CALLER_FUNC:%.*]] = function_ref @$s21attr_execution_silgen29globalCallerFuncSendableKlassyyAA0gH0CYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()
-// FIVE:    [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CALLER_FUNC]] to $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()
-// FIVE:    [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCIegHgg_ADIegHg_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> ()
-// FIVE:    [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[TTFI]]) :
-// SIX:     [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCIetHgg_ADIeghHg_TRScMTU : $@convention(thin) @Sendable @async (@guaranteed SendableKlass, @convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> ()
-// SIX:     [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[GLOBAL_CALLER_FUNC]]) :
-// CHECK:   [[V1:%.*]] = move_value [lexical] [var_decl] [[PA]]
-// CHECK:   [[V1_B:%.*]] = begin_borrow [[V1]]
-// CHECK:   [[V1_B_C:%.*]] = copy_value [[V1_B]]
-// CHECK:   [[V1_B_C_B:%.*]] = begin_borrow [[V1_B_C]]
-// FIVE:    apply [[V1_B_C_B]]({{%.*}}) : $@async @callee_guaranteed (@guaranteed SendableKlass) -> ()
-// SIX:     apply [[V1_B_C_B]]({{%.*}}) : $@Sendable @async @callee_guaranteed (@guaranteed SendableKlass) -> ()
-
-// CHECK:   [[GLOBAL_CONCURRENT_FUNC:%.*]] = function_ref @$s21attr_execution_silgen33globalConcurrentFuncSendableKlassyyAA0gH0CYaF : $@convention(thin) @async (@guaranteed SendableKlass) -> ()
-// CHECK:   [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CONCURRENT_FUNC]] to $@async @callee_guaranteed (@guaranteed SendableKlass) -> ()
-// FIVE:    [[V2:%.*]] = move_value [lexical] [var_decl] [[TTFI]]
-// SIX:     [[CVT:%.*]] = convert_function [[TTFI]] to $@Sendable @async @callee_guaranteed (@guaranteed SendableKlass) -> ()
-// SIX:     [[V2:%.*]] = move_value [lexical] [var_decl] [[CVT]]
-// CHECK:   [[V2_B:%.*]] = begin_borrow [[V2]]
-// CHECK:   [[V2_B_C:%.*]] = copy_value [[V2_B]]
-// CHECK:   [[V2_B_C_B:%.*]] = begin_borrow [[V2_B_C]]
-// CHECK:   apply [[V2_B_C_B]]({{%.*}})
-
-// FIVE:   [[X_C:%.*]] = copy_value [[X]]
-// FIVE:   [[V3:%.*]] = move_value [lexical] [var_decl] [[X_C]]
-// FIVE:   [[V3_B:%.*]] = begin_borrow [[V3]]
-// FIVE:   [[V3_B_C:%.*]] = copy_value [[V3_B]]
-// FIVE:   [[V3_B_C_B:%.*]] = begin_borrow [[V3_B_C]]
-// FIVE:   apply [[V3_B_C_B]]({{%.*}})
-
-// FIVE:   [[Y_C:%.*]] = copy_value [[Y]]
-// FIVE:   [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCIegHgg_ADIegHg_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> ()) -> ()
-// FIVE:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
-// FIVE:   [[V4:%.*]] = move_value [lexical] [var_decl] [[PA]]
-// FIVE:   [[V4_B:%.*]] = begin_borrow [[V4]]
-// FIVE:   [[V4_B_C:%.*]] = copy_value [[V4_B]]
-// FIVE:   [[V4_B_C_B:%.*]] = begin_borrow [[V4_B_C]]
-// FIVE:   apply [[V4_B_C_B]]({{%.*}})
-
-// CHECK: } // end sil function '$s21attr_execution_silgen23globalActorConversions2yyyAA13SendableKlassCYac_yADYaYCctYaF'
-func globalActorConversions2(_ x: @escaping @execution(concurrent) (SendableKlass) async -> (),
-                             _ y: @escaping @execution(caller) (SendableKlass) async -> ()) async {
-  let v1: @MainActor (SendableKlass) async -> Void = globalCallerFuncSendableKlass
-  await v1(SendableKlass())
-  let v2: @MainActor (SendableKlass) async -> Void = globalConcurrentFuncSendableKlass
-  await v2(SendableKlass())
-#if SWIFT_FIVE
-  let v3: @MainActor (SendableKlass) async -> Void = x
-  await v3(SendableKlass())
-  let v4: @MainActor (SendableKlass) async -> Void = y
-  await v4(SendableKlass())
-#endif
-  let v5: @execution(concurrent) (SendableKlass) async -> Void = y
-  await v5(SendableKlass())
-}
-
-// CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen23globalActorConversions3yyAA13SendableKlassCADYac_A2DYaYCctYaF : $@convention(thin) @async (@guaranteed @async @callee_guaranteed (@guaranteed SendableKlass) -> @owned SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> () {
-// CHECK: bb0([[X:%.*]] : @guaranteed $@async @callee_guaranteed (@guaranteed SendableKlass) -> @owned SendableKlass, [[Y:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass):
-// CHECK:   [[GLOBAL_CALLER_FUNC:%.*]] = function_ref @$s21attr_execution_silgen29globalCallerFuncSendableKlassyAA0gH0CADYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass
-// FIVE:    [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CALLER_FUNC]] to $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass
-// FIVE:    [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHggo_A2DIegHgo_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass
-// FIVE:    [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[TTFI]])
-// SIX:     [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCADIetHggo_A2DIeghHgo_TRScMTU : $@convention(thin) @Sendable @async (@guaranteed SendableKlass, @convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass
-// SIX:     [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[GLOBAL_CALLER_FUNC]])
-// CHECK:   [[V1:%.*]] = move_value [lexical] [var_decl] [[PA]]
-// CHECK:   [[V1_B:%.*]] = begin_borrow [[V1]]
-// CHECK:   [[V1_B_C:%.*]] = copy_value [[V1_B]]
-// CHECK:   [[V1_B_C_B:%.*]] = begin_borrow [[V1_B_C]]
-// CHECK:   apply [[V1_B_C_B]]({{%.*}})
-
-// CHECK:   [[GLOBAL_CONCURRENT_FUNC:%.*]] = function_ref @$s21attr_execution_silgen33globalConcurrentFuncSendableKlassyAA0gH0CADYaF : $@convention(thin) @async (@guaranteed SendableKlass) -> @owned SendableKlass
-// CHECK:   [[TTFI:%.*]] = thin_to_thick_function [[GLOBAL_CONCURRENT_FUNC]] to $@async @callee_guaranteed (@guaranteed SendableKlass) -> @owned SendableKlass
-// FIVE:    [[V2:%.*]] = move_value [lexical] [var_decl] [[TTFI]]
-// SIX:     [[CVT:%.*]] = convert_function [[TTFI]] to $@Sendable @async @callee_guaranteed (@guaranteed SendableKlass) -> @owned SendableKlass
-// SIX:     [[V2:%.*]] = move_value [lexical] [var_decl] [[CVT]]
-// CHECK:   [[V2_B:%.*]] = begin_borrow [[V2]]
-// CHECK:   [[V2_B_C:%.*]] = copy_value [[V2_B]]
-// CHECK:   [[V2_B_C_B:%.*]] = begin_borrow [[V2_B_C]]
-// CHECK:   apply [[V2_B_C_B]]({{%.*}})
-
-// FIVE:   [[X_C:%.*]] = copy_value [[X]]
-// FIVE:   [[V3:%.*]] = move_value [lexical] [var_decl] [[X_C]]
-// FIVE:   [[V3_B:%.*]] = begin_borrow [[V3]]
-// FIVE:   [[V3_B_C:%.*]] = copy_value [[V3_B]]
-// FIVE:   [[V3_B_C_B:%.*]] = begin_borrow [[V3_B_C]]
-// FIVE:   apply [[V3_B_C_B]]({{%.*}})
-
-// FIVE:   [[Y_C:%.*]] = copy_value [[Y]]
-// FIVE:   [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHggo_A2DIegHgo_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass
-// FIVE:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
-// FIVE:   [[V4:%.*]] = move_value [lexical] [var_decl] [[PA]]
-// FIVE:   [[V4_B:%.*]] = begin_borrow [[V4]]
-// FIVE:   [[V4_B_C:%.*]] = copy_value [[V4_B]]
-// FIVE:   [[V4_B_C_B:%.*]] = begin_borrow [[V4_B_C]]
-// FIVE:   apply [[V4_B_C_B]]({{%.*}})
-
-// CHECK:  [[Y_C:%.*]] = copy_value [[Y]]
-// CHECK:  [[THUNK:%.*]] = function_ref @$sScA_pSg21attr_execution_silgen13SendableKlassCADIegHggo_A2DIegHgo_TR : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass) -> @owned SendableKlass) -> @owned SendableKlass
-// CHECK:  [[PA:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
-// CHECK:  [[V5:%.*]] = move_value [lexical] [var_decl] [[PA]]
-// CHECK: } // end sil function '$s21attr_execution_silgen23globalActorConversions3yyAA13SendableKlassCADYac_A2DYaYCctYaF'
-func globalActorConversions3(_ x: @escaping @execution(concurrent) (SendableKlass) async -> SendableKlass,
-                             _ y: @escaping @execution(caller) (SendableKlass) async -> SendableKlass) async {
-  let v1: @MainActor (SendableKlass) async -> SendableKlass = globalCallerFuncSendableKlass
-  _ = await v1(SendableKlass())
-  let v2: @MainActor (SendableKlass) async -> SendableKlass = globalConcurrentFuncSendableKlass
-  _ = await v2(SendableKlass())
-#if SWIFT_FIVE
-  let v3: @MainActor (SendableKlass) async -> SendableKlass = x
-  _ = await v3(SendableKlass())
-  let v4: @MainActor (SendableKlass) async -> SendableKlass = y
-  _ = await v4(SendableKlass())
-#endif
-  let v5: @execution(concurrent) (SendableKlass) async -> SendableKlass = y
-  _ = await v5(SendableKlass())
-}
-
-// CHECK-LABEL: sil hidden [ossa] @$s21attr_execution_silgen26conversionsFromSyncToAsyncyyyAA16NonSendableKlassCYbc_yAA0jK0CYbScMYccyADYbScMYcctYaF : $@convention(thin) @async (@guaranteed @Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> (), @guaranteed @Sendable @callee_guaranteed (@guaranteed SendableKlass) -> (), @guaranteed @Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> ()) -> () {
-// CHECK: bb0([[X:%.*]] : @guaranteed $@Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> (), [[Y:%.*]] : @guaranteed $@Sendable @callee_guaranteed (@guaranteed SendableKlass) -> (), [[Z:%.*]] : @guaranteed $@Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> ()):
-
-// CHECK:   [[X_C:%.*]] = copy_value [[X]]
-// CHECK:   [[THUNK:%.*]] = function_ref @$s21attr_execution_silgen16NonSendableKlassCIeghg_ScA_pSgACIegHgg_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed NonSendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> ()) -> ()
-// CHECK:   [[PAI:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[X_C]])
-
-// CHECK:   [[Y_C:%.*]] = copy_value [[Y]]
-// CHECK:   [[THUNK:%.*]] = function_ref @$s21attr_execution_silgen13SendableKlassCIeghg_ScA_pSgACIegHgg_TRScMTU : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed SendableKlass) -> ()) -> ()
-// CHECK:   [[PAI:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
-
-// CHECK:   [[Y_C:%.*]] = copy_value [[Y]]
-// CHECK:   [[THUNK:%.*]] = function_ref @$s21attr_execution_silgen13SendableKlassCIeghg_ACIegHg_TRScMTU : $@convention(thin) @async (@guaranteed SendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed SendableKlass) -> ()) -> ()
-// CHECK:   [[PAI:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Y_C]])
-
-// CHECK:   [[Z_C:%.*]] = copy_value [[Z]]
-// CHECK:   [[THUNK:%.*]] = function_ref @$s21attr_execution_silgen16NonSendableKlassCIeghg_ACIegHg_TRScMTU : $@convention(thin) @async (@guaranteed NonSendableKlass, @guaranteed @Sendable @callee_guaranteed (@guaranteed NonSendableKlass) -> ()) -> ()
-// CHECK:   [[PAI:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[Z_C]])
-
-// CHECK: } // end sil function '$s21attr_execution_silgen26conversionsFromSyncToAsyncyyyAA16NonSendableKlassCYbc_yAA0jK0CYbScMYccyADYbScMYcctYaF'
-
-func conversionsFromSyncToAsync(_ x: @escaping @Sendable (NonSendableKlass) -> Void,
-                                _ y: @escaping @MainActor @Sendable (SendableKlass) -> Void,
-                                _ z: @escaping @MainActor @Sendable (NonSendableKlass) -> Void) async {
-  let _: @execution(caller) (NonSendableKlass) async -> Void = x
-  let _: @execution(caller) (SendableKlass) async -> Void = y
-  let _: @execution(concurrent) (SendableKlass) async -> Void = y
-  let _: @execution(concurrent) (NonSendableKlass) async -> Void = z
-}
diff --git a/test/Concurrency/attr_execution/witnesses.swift b/test/Concurrency/attr_execution/witnesses.swift
new file mode 100644
index 0000000000000..6b649f09ed8b8
--- /dev/null
+++ b/test/Concurrency/attr_execution/witnesses.swift
@@ -0,0 +1,102 @@
+// RUN: %target-swift-emit-silgen %s -swift-version 6 -target %target-swift-5.1-abi-triple | %FileCheck %s
+
+// REQUIRES: asserts
+// REQUIRES: concurrency
+
+protocol P {
+  nonisolated(nonsending) var prop: String { get async }
+  nonisolated(nonsending) func fn() async
+}
+
+struct S: P {
+  var prop: String {
+    get async { "" }
+  }
+
+  func fn() async {
+  }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s9witnesses21testMainActorDispatch1tyx_tYaAA1PRzlF : $@convention(thin) @async <T where T : P> (@in_guaranteed T) -> ()
+// CHECK: [[MAIN_ACTOR_TYPE:%.*]] = metatype $@thick MainActor.Type
+// CHECK: [[MAIN_ACTOR:%.*]] = apply {{.*}}([[MAIN_ACTOR_TYPE]]) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// CHECK-NEXT: [[BORROWED_MAIN_ACTOR:%.*]] = begin_borrow [[MAIN_ACTOR]]
+// CHECK-NEXT: hop_to_executor [[BORROWED_MAIN_ACTOR]]
+// CHECK-NEXT: [[MAIN_ACTOR_COPY:%.*]] = copy_value [[BORROWED_MAIN_ACTOR]]
+// CHECK-NEXT: [[ERASED_TO_ACTOR:%.*]] = init_existential_ref [[MAIN_ACTOR_COPY]] : $MainActor : $MainActor, $any Actor
+// CHECK-NEXT: [[CONTEXT_ISOLATION:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[ERASED_TO_ACTOR]]
+// CHECK-NEXT: [[PROP_WITNESS:%.*]] = witness_method $T, #P.prop!getter : <Self where Self : P> (Self) -> () async -> String : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> @owned String
+// CHECK-NEXT: {{.*}} = apply [[PROP_WITNESS]]<T>([[CONTEXT_ISOLATION]], %0) : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> @owned String
+// CHECK: hop_to_executor [[BORROWED_MAIN_ACTOR]]
+// CHECK: [[MAIN_ACTOR_COPY:%.*]] = copy_value [[BORROWED_MAIN_ACTOR]]
+// CHECK-NEXT: [[ERASED_TO_ACTOR:%.*]] = init_existential_ref [[MAIN_ACTOR_COPY]] : $MainActor : $MainActor, $any Actor
+// CHECK-NEXT: [[CONTEXT_ISOLATION:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[ERASED_TO_ACTOR]]
+// CHECK-NEXT: [[FN_WITNESS:%.*]] = witness_method $T, #P.fn : <Self where Self : P> (Self) -> () async -> () : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> ()
+// CHECK-NEXT: {{.*}} = apply [[FN_WITNESS]]<T>([[CONTEXT_ISOLATION]], %0) : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> ()
+// CHECK: } // end sil function '$s9witnesses21testMainActorDispatch1tyx_tYaAA1PRzlF'
+@MainActor
+func testMainActorDispatch<T: P>(t: T) async {
+  _ = await t.prop
+  _ = await t.fn()
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s9witnesses19testGenericExecutor1tyx_tYaAA1PRzlF : $@convention(thin) @async <T where T : P> (@in_guaranteed T) -> ()
+// CHECK: [[CONTEXT_ISOLATION:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+// CHECK-NEXT: hop_to_executor [[CONTEXT_ISOLATION]]
+// CHECK-NEXT: [[ISOLATION_ERASED_TO_ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK-NEXT: [[PROP_WITNESS:%.*]] = witness_method $T, #P.prop!getter : <Self where Self : P> (Self) -> () async -> String : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> @owned String
+// CHECK-NEXT: {{.*}} = apply [[PROP_WITNESS]]<T>([[ISOLATION_ERASED_TO_ACTOR]], %0) : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> @owned String
+// CHECK-NEXT: hop_to_executor [[CONTEXT_ISOLATION]]
+// CHECK: [[ISOLATION_ERASED_TO_ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK-NEXT: [[FN_WITNESS:%.*]] = witness_method $T, #P.fn : <Self where Self : P> (Self) -> () async -> () : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> ()
+// CHECK-NEXT: {{.*}} = apply [[FN_WITNESS]]<T>([[ISOLATION_ERASED_TO_ACTOR]], %0) : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> ()
+// CHECK: } // end sil function '$s9witnesses19testGenericExecutor1tyx_tYaAA1PRzlF'
+func testGenericExecutor<T: P>(t: T) async {
+  _ = await t.prop
+  _ = await t.fn()
+}
+
+actor Test {
+  // CHECK-LABEL: sil hidden [ossa] @$s9witnesses4TestC4test1tyx_tYaAA1PRzlF : $@convention(method) @async <T where T : P> (@in_guaranteed T, @sil_isolated @guaranteed Test) -> ()
+  // CHECK: bb0(%0 : $*T, [[ACTOR:%.*]] : @guaranteed $Test):
+  // CHECK: hop_to_executor [[ACTOR]]
+  // CHECK-NEXT: [[ACTOR_COPY:%.*]] = copy_value [[ACTOR]]
+  // CHECK-NEXT: [[ERASED_TO_ACTOR:%.*]] = init_existential_ref [[ACTOR_COPY]] : $Test : $Test, $any Actor
+  // CHECK-NEXT: [[CONTEXT_ISOLATION:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[ERASED_TO_ACTOR]]
+  // CHECK-NEXT: [[PROP_WITNESS:%.*]] = witness_method $T, #P.prop!getter : <Self where Self : P> (Self) -> () async -> String : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> @owned String
+  // CHECK-NEXT: {{.*}} = apply [[PROP_WITNESS]]<T>([[CONTEXT_ISOLATION]], %0) : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> @owned String
+  // CHECK: hop_to_executor [[ACTOR]]
+  // CHECK: [[ACTOR_COPY:%.*]] = copy_value [[ACTOR]]
+  // CHECK-NEXT: [[ERASED_TO_ACTOR:%.*]] = init_existential_ref [[ACTOR_COPY]] : $Test : $Test, $any Actor
+  // CHECK-NEXT: [[CONTEXT_ISOLATION:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[ERASED_TO_ACTOR]]
+  // CHECK-NEXT: [[FN_WITNESS:%.*]] = witness_method $T, #P.fn : <Self where Self : P> (Self) -> () async -> () : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> ()
+  // CHECK-NEXT: {{.*}} = apply [[FN_WITNESS]]<T>([[CONTEXT_ISOLATION]], %0) : $@convention(witness_method: P) @async <τ_0_0 where τ_0_0 : P> (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed τ_0_0) -> ()
+  // CHECK: } // end sil function '$s9witnesses4TestC4test1tyx_tYaAA1PRzlF'
+  func test<T: P>(t: T) async {
+    _ = await t.prop
+    _ = await t.fn()
+  }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s9witnesses14testDirectCall1syAA1SV_tYaF : $@convention(thin) @async (S) -> ()
+// CHECK: [[MAIN_ACTOR_TYPE:%.*]] = metatype $@thick MainActor.Type
+// CHECK: [[MAIN_ACTOR:%.*]] = apply {{.*}}([[MAIN_ACTOR_TYPE]]) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// CHECK-NEXT: [[BORROWED_MAIN_ACTOR:%.*]] = begin_borrow [[MAIN_ACTOR]]
+// CHECK-NEXT: hop_to_executor [[BORROWED_MAIN_ACTOR]]
+// CHECK-NEXT: [[MAIN_ACTOR_COPY:%.*]] = copy_value [[BORROWED_MAIN_ACTOR]]
+// CHECK-NEXT: [[ERASED_TO_ACTOR:%.*]] = init_existential_ref [[MAIN_ACTOR_COPY]] : $MainActor : $MainActor, $any Actor
+// CHECK-NEXT: [[CONTEXT_ISOLATION:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[ERASED_TO_ACTOR]]
+// CHECK: [[PROP_REF:%.*]] = function_ref @$s9witnesses1SV4propSSvg : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, S) -> @owned String
+// CHECK-NEXT: {{.*}} = apply [[PROP_REF]]([[CONTEXT_ISOLATION]], %0) : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, S) -> @owned String
+// CHECK: hop_to_executor [[BORROWED_MAIN_ACTOR]]
+// CHECK: [[MAIN_ACTOR_COPY:%.*]] = copy_value [[BORROWED_MAIN_ACTOR]]
+// CHECK-NEXT: [[ERASED_TO_ACTOR:%.*]] = init_existential_ref [[MAIN_ACTOR_COPY]] : $MainActor : $MainActor, $any Actor
+// CHECK-NEXT: [[CONTEXT_ISOLATION:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[ERASED_TO_ACTOR]]
+// CHECK: [[FN_REF:%.*]] = function_ref @$s9witnesses1SV2fnyyYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, S) -> ()
+// CHECK-NEXT: {{.*}} = apply [[FN_REF]]([[CONTEXT_ISOLATION]], %0) : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, S) -> ()
+// CHECK: } // end sil function '$s9witnesses14testDirectCall1syAA1SV_tYaF'
+@MainActor
+func testDirectCall(s: S) async {
+  _ = await s.prop
+  _ = await s.fn()
+}
diff --git a/test/Concurrency/concurrency_availability.swift b/test/Concurrency/concurrency_availability.swift
index 18c581c9644ac..609687170854e 100644
--- a/test/Concurrency/concurrency_availability.swift
+++ b/test/Concurrency/concurrency_availability.swift
@@ -6,10 +6,10 @@
 import _Concurrency
 
 func f() async { } // expected-error{{concurrency is only available in}}
-// expected-note@-1{{add @available}}
+// expected-note@-1{{add '@available'}}
 
 actor A { }  // expected-error{{concurrency is only available in}}
-// expected-note@-1{{add @available}}
+// expected-note@-1{{add '@available'}}
 
 // Allow this without any availability for Historical Reasons.
 public func swift_deletedAsyncMethodError() async {
diff --git a/test/Concurrency/concurrency_module_shadowing.swift b/test/Concurrency/concurrency_module_shadowing.swift
index a6d11b22ff6d5..32362ad67f967 100644
--- a/test/Concurrency/concurrency_module_shadowing.swift
+++ b/test/Concurrency/concurrency_module_shadowing.swift
@@ -5,10 +5,8 @@
 // RUN: %target-swift-frontend -I %t  -disable-availability-checking %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -I %t  -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -I %t  -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -I %t  -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 import ShadowsConcur
 
@@ -19,3 +17,8 @@ func f(_ t : UnsafeCurrentTask) -> Bool {
 
 @available(SwiftStdlib 5.1, *)
 func g(_: _Concurrency.UnsafeCurrentTask) {}
+
+// Should also be allowed since _Concurrency is a separately-imported overlay of
+// the standard library.
+@available(SwiftStdlib 5.1, *)
+func h(_: Swift.UnsafeCurrentTask) {}
diff --git a/test/Concurrency/concurrency_warnings.swift b/test/Concurrency/concurrency_warnings.swift
index c9cc307fc77b4..474973e6f978f 100644
--- a/test/Concurrency/concurrency_warnings.swift
+++ b/test/Concurrency/concurrency_warnings.swift
@@ -2,7 +2,7 @@
 
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/GlobalVariables.swiftmodule -module-name GlobalVariables %S/Inputs/GlobalVariables.swift -disable-availability-checking -parse-as-library
 
-// RUN: %target-swift-frontend -I %t -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify
+// RUN: %target-swift-frontend -I %t -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
@@ -17,7 +17,7 @@ let rs = GlobalCounter() // expected-warning {{let 'rs' is not concurrency-safe
 
 import GlobalVariables
 
-class MyError: Error { // expected-warning{{non-final class 'MyError' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+class MyError: Error { // expected-warning{{non-final class 'MyError' cannot conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode}}
   var storage = 0 // expected-warning{{stored property 'storage' of 'Sendable'-conforming class 'MyError' is mutable}}
 }
 
diff --git a/test/Concurrency/concurrent_value_checking.swift b/test/Concurrency/concurrent_value_checking.swift
index 627eadd2a0dda..b3b13cfffa4a6 100644
--- a/test/Concurrency/concurrent_value_checking.swift
+++ b/test/Concurrency/concurrent_value_checking.swift
@@ -1,12 +1,11 @@
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -DALLOW_TYPECHECKER_ERRORS -verify-additional-prefix typechecker- -verify-additional-prefix tns-allow-typechecker-
-
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -verify-additional-prefix tns-
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 class NotConcurrent { } // expected-note 12{{class 'NotConcurrent' does not conform to the 'Sendable' protocol}}
-// expected-tns-allow-typechecker-note @-1 {{class 'NotConcurrent' does not conform to the 'Sendable' protocol}}
 
 // ----------------------------------------------------------------------
 // Sendable restriction on actor operations
@@ -67,24 +66,24 @@ actor A2 {
 
 func testActorCreation(value: NotConcurrent) async {
   _ = A2(value: value)
-  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(value:)' risks causing data races between actor-isolated and task-isolated uses}}
+  // expected-warning @-1 {{sending 'value' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(value:)' risks causing data races between actor-isolated and task-isolated uses}}
 
   _ = await A2(valueAsync: value)
-  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(valueAsync:)' risks causing data races between actor-isolated and task-isolated uses}}
+  // expected-warning @-1 {{sending 'value' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(valueAsync:)' risks causing data races between actor-isolated and task-isolated uses}}
 
   _ = A2(delegatingSync: value)
-  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(delegatingSync:)' risks causing data races between actor-isolated and task-isolated uses}}
+  // expected-warning @-1 {{sending 'value' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(delegatingSync:)' risks causing data races between actor-isolated and task-isolated uses}}
 
   _ = await A2(delegatingAsync: value, 9)
-  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(delegatingAsync:_:)' risks causing data races between actor-isolated and task-isolated uses}}
+  // expected-warning @-1 {{sending 'value' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(delegatingAsync:_:)' risks causing data races between actor-isolated and task-isolated uses}}
 
   _ = await A2(nonisoAsync: value, 3)
-  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(nonisoAsync:_:)' risks causing data races between actor-isolated and task-isolated uses}}
+  // expected-warning @-1 {{sending 'value' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(nonisoAsync:_:)' risks causing data races between actor-isolated and task-isolated uses}}
 }
 
 extension A1 {
@@ -99,10 +98,9 @@ extension A1 {
     _ = await self.asynchronous(nil)
 
     // Across to a different actor, so Sendable restriction is enforced.
-    _ = other.localLet // expected-warning{{non-sendable type 'NotConcurrent' of property 'localLet' cannot exit actor-isolated context}}
-    // expected-warning@-1 {{expression is 'async' but is not marked with 'await'}}
-    // expected-note@-2 {{property access is 'async'}}
-    _ = await other.synchronous() // expected-tns-warning {{non-Sendable 'NotConcurrent?'-typed result can not be returned from actor-isolated instance method 'synchronous()' to actor-isolated context}}
+    _ = other.localLet // expected-warning{{non-Sendable type 'NotConcurrent' of property 'localLet' cannot exit actor-isolated context}}
+    // expected-warning@-1 {{actor-isolated property 'localLet' cannot be accessed from outside of the actor}} {{9-9=await }}
+    _ = await other.synchronous() // expected-warning {{non-Sendable 'NotConcurrent?'-typed result can not be returned from actor-isolated instance method 'synchronous()' to actor-isolated context}}
     _ = await other.asynchronous(nil)
   }
 }
@@ -138,25 +136,13 @@ enum E {
 }
 
 func globalTest() async {
-  // expected-warning@+2 {{expression is 'async' but is not marked with 'await'}}
-  // expected-note@+1 {{property access is 'async'}}
-  let a = globalValue // expected-warning{{non-sendable type 'NotConcurrent?' of let 'globalValue' cannot exit global actor 'SomeGlobalActor'-isolated context}}
-  await globalAsync(a) // expected-tns-warning {{sending 'a' risks causing data races}}
-  // expected-tns-note @-1 {{sending global actor 'SomeGlobalActor'-isolated 'a' to global actor 'SomeGlobalActor'-isolated global function 'globalAsync' risks causing data races between global actor 'SomeGlobalActor'-isolated and local nonisolated uses}}
-  await globalSync(a) // expected-tns-note {{access can happen concurrently}}
-
-  // expected-warning@+2 {{expression is 'async' but is not marked with 'await'}}
-  // expected-note@+1 {{property access is 'async'}}
-  let _ = E.notSafe // expected-warning{{non-sendable type 'NotConcurrent?' of static property 'notSafe' cannot exit global actor 'SomeGlobalActor'-isolated context}}
-
-#if ALLOW_TYPECHECKER_ERRORS
-  // expected-typechecker-error@+3 {{expression is 'async' but is not marked with 'await'}}
-  // expected-typechecker-note@+2 {{call is 'async'}}
-  // expected-typechecker-note@+1 {{property access is 'async'}}
-  globalAsync(E.notSafe)
+  // expected-warning@+1 {{global actor 'SomeGlobalActor'-isolated let 'globalValue' cannot be accessed from outside of the actor}} {{11-11=await }}
+  let a = globalValue // expected-warning{{non-Sendable type 'NotConcurrent?' of let 'globalValue' cannot exit global actor 'SomeGlobalActor'-isolated context}}
+  await globalAsync(a)
+  await globalSync(a)
 
-  // expected-typechecker-warning@-2 {{non-sendable type 'NotConcurrent?' of static property 'notSafe' cannot exit global actor 'SomeGlobalActor'-isolated context}}
-#endif
+  // expected-warning@+1 {{global actor 'SomeGlobalActor'-isolated static property 'notSafe' cannot be accessed from outside of the actor}} {{11-11=await }}
+  let _ = E.notSafe // expected-warning{{non-Sendable type 'NotConcurrent?' of static property 'notSafe' cannot exit global actor 'SomeGlobalActor'-isolated context}}
 }
 
 struct HasSubscript {
@@ -164,7 +150,7 @@ struct HasSubscript {
   subscript (i: Int) -> NotConcurrent? { nil }
 }
 
-class ClassWithGlobalActorInits { // expected-tns-note 2{{class 'ClassWithGlobalActorInits' does not conform to the 'Sendable' protocol}}
+class ClassWithGlobalActorInits { // expected-note 2{{class 'ClassWithGlobalActorInits' does not conform to the 'Sendable' protocol}}
   @SomeGlobalActor
   init(_: NotConcurrent) { }
 
@@ -175,17 +161,15 @@ class ClassWithGlobalActorInits { // expected-tns-note 2{{class 'ClassWithGlobal
 
 @MainActor
 func globalTestMain(nc: NotConcurrent) async {
-  // expected-warning@+2 {{expression is 'async' but is not marked with 'await'}}
-  // expected-note@+1 {{property access is 'async'}}
-  let a = globalValue // expected-warning {{non-sendable type 'NotConcurrent?' of let 'globalValue' cannot exit global actor 'SomeGlobalActor'-isolated context}}
-  await globalAsync(a) // expected-tns-warning {{sending 'a' risks causing data races}}
-  // expected-tns-note @-1 {{sending global actor 'SomeGlobalActor'-isolated 'a' to global actor 'SomeGlobalActor'-isolated global function 'globalAsync' risks causing data races between global actor 'SomeGlobalActor'-isolated and local main actor-isolated uses}}
-  await globalSync(a) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning@+1 {{global actor 'SomeGlobalActor'-isolated let 'globalValue' cannot be accessed from outside of the actor}} {{11-11=await }}
+  let a = globalValue // expected-warning {{non-Sendable type 'NotConcurrent?' of let 'globalValue' cannot exit global actor 'SomeGlobalActor'-isolated context}}
+  await globalAsync(a)
+  await globalSync(a)
   _ = await ClassWithGlobalActorInits(nc)
-  // expected-tns-warning @-1 {{non-Sendable 'ClassWithGlobalActorInits'-typed result can not be returned from global actor 'SomeGlobalActor'-isolated initializer 'init(_:)' to main actor-isolated context}}
-  // expected-tns-warning @-2 {{sending 'nc' risks causing data races}}
-  // expected-tns-note @-3 {{sending main actor-isolated 'nc' to global actor 'SomeGlobalActor'-isolated initializer 'init(_:)' risks causing data races between global actor 'SomeGlobalActor'-isolated and main actor-isolated uses}}
-  _ = await ClassWithGlobalActorInits() // expected-tns-warning {{non-Sendable 'ClassWithGlobalActorInits'-typed result can not be returned from global actor 'SomeGlobalActor'-isolated initializer 'init()' to main actor-isolated context}}
+  // expected-warning @-1 {{non-Sendable 'ClassWithGlobalActorInits'-typed result can not be returned from global actor 'SomeGlobalActor'-isolated initializer 'init(_:)' to main actor-isolated context}}
+  // expected-warning @-2 {{sending 'nc' risks causing data races}}
+  // expected-note @-3 {{sending main actor-isolated 'nc' to global actor 'SomeGlobalActor'-isolated initializer 'init(_:)' risks causing data races between global actor 'SomeGlobalActor'-isolated and main actor-isolated uses}}
+  _ = await ClassWithGlobalActorInits() // expected-warning {{non-Sendable 'ClassWithGlobalActorInits'-typed result can not be returned from global actor 'SomeGlobalActor'-isolated initializer 'init()' to main actor-isolated context}}
 }
 
 @SomeGlobalActor
@@ -210,8 +194,8 @@ func testConcurrency() {
     print(y) // okay
   }
   acceptConcurrent {
-    print(x) // expected-warning{{capture of 'x' with non-sendable type 'NotConcurrent' in a '@Sendable' closure}}
-    print(y) // expected-warning{{capture of 'y' with non-sendable type 'NotConcurrent' in a '@Sendable' closure}}
+    print(x) // expected-warning{{capture of 'x' with non-Sendable type 'NotConcurrent' in a '@Sendable' closure}}
+    print(y) // expected-warning{{capture of 'y' with non-Sendable type 'NotConcurrent' in a '@Sendable' closure}}
     // expected-warning@-1{{reference to captured var 'y' in concurrently-executing code}}
   }
 }
@@ -247,7 +231,7 @@ class HasNC {
 }
 
 func testKeyPaths(dict: [NC: Int], nc: NC) {
-  _ = \HasNC.dict[nc] // expected-warning{{cannot form key path that captures non-sendable type 'NC'}}
+  _ = \HasNC.dict[nc] // expected-warning{{cannot form key path that captures non-Sendable type 'NC'}}
 }
 
 // ----------------------------------------------------------------------
@@ -259,7 +243,7 @@ actor ANI {
 }
 
 func testANI(ani: ANI) async {
-  _ = ani.nc // expected-warning{{non-sendable type 'NC' of property 'nc' cannot exit nonisolated context}}
+  _ = ani.nc // expected-warning{{non-Sendable type 'NC' of property 'nc' cannot exit nonisolated context}}
 }
 
 // ----------------------------------------------------------------------
@@ -270,7 +254,7 @@ protocol AsyncProto {
 }
 
 extension A1: AsyncProto {
-  func asyncMethod(_: NotConcurrent) async { } // expected-warning{{non-sendable parameter type 'NotConcurrent' cannot be sent from caller of protocol requirement 'asyncMethod' into actor-isolated implementation}}
+  func asyncMethod(_: NotConcurrent) async { } // expected-warning{{non-Sendable parameter type 'NotConcurrent' cannot be sent from caller of protocol requirement 'asyncMethod' into actor-isolated implementation}}
 }
 
 protocol MainActorProto {
@@ -279,7 +263,7 @@ protocol MainActorProto {
 
 class SomeClass: MainActorProto {
   @SomeGlobalActor
-  func asyncMainMethod(_: NotConcurrent) async { } // expected-warning{{non-sendable parameter type 'NotConcurrent' cannot be sent from caller of protocol requirement 'asyncMainMethod' into global actor 'SomeGlobalActor'-isolated implementation}}
+  func asyncMainMethod(_: NotConcurrent) async { } // expected-warning{{non-Sendable parameter type 'NotConcurrent' cannot be sent from caller of protocol requirement 'asyncMainMethod' into global actor 'SomeGlobalActor'-isolated implementation}}
 }
 
 // ----------------------------------------------------------------------
@@ -305,10 +289,10 @@ var concurrentFuncVar: (@Sendable (NotConcurrent) -> Void)? = nil // expected-wa
 // ----------------------------------------------------------------------
 func acceptConcurrentUnary<T>(_: @Sendable (T) -> T) { }
 
-func concurrentClosures<T>(_: T) { // expected-note{{consider making generic parameter 'T' conform to the 'Sendable' protocol}} {{26-26=: Sendable}}
+func concurrentClosures<T: SendableMetatype>(_: T) { // expected-note{{consider making generic parameter 'T' conform to the 'Sendable' protocol}} {{44-44= & Sendable}}
   acceptConcurrentUnary { (x: T) in
     _ = x // ok
-    acceptConcurrentUnary { _ in x } // expected-warning{{capture of 'x' with non-sendable type 'T' in a '@Sendable' closure}}
+    acceptConcurrentUnary { _ in x } // expected-warning{{capture of 'x' with non-Sendable type 'T' in a '@Sendable' closure}}
     let y: T? = nil
     return y!
   }
@@ -318,11 +302,11 @@ func concurrentClosures<T>(_: T) { // expected-note{{consider making generic par
 // Sendable checking
 // ----------------------------------------------------------------------
 struct S1: Sendable {
-  var nc: NotConcurrent // expected-warning{{stored property 'nc' of 'Sendable'-conforming struct 'S1' has non-sendable type 'NotConcurrent'}}
+  var nc: NotConcurrent // expected-warning{{stored property 'nc' of 'Sendable'-conforming struct 'S1' has non-Sendable type 'NotConcurrent'}}
 }
 
 struct S2<T>: Sendable { // expected-note{{consider making generic parameter 'T' conform to the 'Sendable' protocol}} {{12-12=: Sendable}}
-  var nc: T // expected-warning{{stored property 'nc' of 'Sendable'-conforming generic struct 'S2' has non-sendable type 'T'}}
+  var nc: T // expected-warning{{stored property 'nc' of 'Sendable'-conforming generic struct 'S2' has non-Sendable type 'T'}}
 }
 
 struct S3<T> {
@@ -333,7 +317,7 @@ struct S3<T> {
 extension S3: Sendable where T: Sendable { }
 
 enum E1: Sendable {
-  case payload(NotConcurrent) // expected-warning{{associated value 'payload' of 'Sendable'-conforming enum 'E1' has non-sendable type 'NotConcurrent'}}
+  case payload(NotConcurrent) // expected-warning{{associated value 'payload' of 'Sendable'-conforming enum 'E1' has non-Sendable type 'NotConcurrent'}}
 }
 
 enum E2<T> {
@@ -343,7 +327,7 @@ enum E2<T> {
 extension E2: Sendable where T: Sendable { }
 
 final class C1: Sendable {
-  let nc: NotConcurrent? = nil // expected-warning{{stored property 'nc' of 'Sendable'-conforming class 'C1' has non-sendable type 'NotConcurrent?'}}
+  let nc: NotConcurrent? = nil // expected-warning{{stored property 'nc' of 'Sendable'-conforming class 'C1' contains non-Sendable type 'NotConcurrent'}}
   var x: Int = 0 // expected-warning{{stored property 'x' of 'Sendable'-conforming class 'C1' is mutable}}
   let i: Int = 0
 }
@@ -379,7 +363,7 @@ extension C6_Restated_Extension: @unchecked Sendable {}
 
 final class C7<T>: Sendable { }
 
-class C9: Sendable { } // expected-warning{{non-final class 'C9' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+class C9: Sendable { } // expected-warning{{non-final class 'C9' cannot conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode}}
 
 @available(*, unavailable)
 extension HasUnavailableSendable : @unchecked Sendable { }
@@ -413,20 +397,20 @@ extension NotConcurrent {
   func f() { }
 
   func test() {
-    Task { // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
-      f() // expected-tns-note {{closure captures 'self' which is accessible to code in the current task}}
+    Task { // expected-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
+      f() // expected-note {{closure captures 'self' which is accessible to code in the current task}}
     }
 
-    Task { // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
-      self.f() // expected-tns-note {{closure captures 'self' which is accessible to code in the current task}}
+    Task { // expected-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
+      self.f() // expected-note {{closure captures 'self' which is accessible to code in the current task}}
     }
 
-    Task { [self] in // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
-      f() // expected-tns-note {{closure captures 'self' which is accessible to code in the current task}}
+    Task { [self] in // expected-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
+      f() // expected-note {{closure captures 'self' which is accessible to code in the current task}}
     }
 
-    Task { [self] in // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
-      self.f() // expected-tns-note {{closure captures 'self' which is accessible to code in the current task}}
+    Task { [self] in // expected-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
+      self.f() // expected-note {{closure captures 'self' which is accessible to code in the current task}}
     }
   }
 }
@@ -447,20 +431,6 @@ enum E11<T>: @unchecked Sendable {
   case other(T) // okay
 }
 
-#if ALLOW_TYPECHECKER_ERRORS
-
-class C11 { }
-
-class C12: @unchecked C11 { } // expected-typechecker-error{{'unchecked' attribute cannot apply to non-protocol type 'C11'}}
-
-protocol P { }
-
-protocol Q: @unchecked Sendable { } // expected-typechecker-error{{'unchecked' attribute only applies in inheritance clauses}}
-
-typealias TypeAlias1 = @unchecked P // expected-typechecker-error{{'unchecked' attribute only applies in inheritance clauses}}
-
-#endif
-
 // ----------------------------------------------------------------------
 // UnsafeSendable historical name
 // ----------------------------------------------------------------------
@@ -475,7 +445,7 @@ enum E12<T>: UnsafeSendable { // expected-warning{{'UnsafeSendable' is deprecate
 func testSendableOptionalInference(nc: NotConcurrent) {
   var fn: (@Sendable () -> Void)? = nil
   fn = {
-    print(nc) // expected-warning{{capture of 'nc' with non-sendable type 'NotConcurrent' in a '@Sendable' closure}}
+    print(nc) // expected-warning{{capture of 'nc' with non-Sendable type 'NotConcurrent' in a '@Sendable' closure}}
   }
   _ = fn
 }
diff --git a/test/Concurrency/concurrent_value_checking_objc.swift b/test/Concurrency/concurrent_value_checking_objc.swift
index 12bc8a7df70c6..5b16ce46233de 100644
--- a/test/Concurrency/concurrent_value_checking_objc.swift
+++ b/test/Concurrency/concurrent_value_checking_objc.swift
@@ -1,8 +1,10 @@
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete %s -emit-sil -o /dev/null -verify
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -verify-additional-prefix ni-
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -verify-additional-prefix ni-ns- -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: objc_interop
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 import Foundation
 
@@ -17,7 +19,7 @@ final class B: NSObject, Sendable {
 class C { } // expected-note{{class 'C' does not conform to the 'Sendable' protocol}}
 
 final class D: NSObject, Sendable {
-  let c: C = C() // expected-warning{{stored property 'c' of 'Sendable'-conforming class 'D' has non-sendable type 'C'}}
+  let c: C = C() // expected-warning{{stored property 'c' of 'Sendable'-conforming class 'D' has non-Sendable type 'C'}}
 }
 
 
diff --git a/test/Concurrency/concurrent_value_checking_typechecker_errors.swift b/test/Concurrency/concurrent_value_checking_typechecker_errors.swift
new file mode 100644
index 0000000000000..85ef8afbd1320
--- /dev/null
+++ b/test/Concurrency/concurrent_value_checking_typechecker_errors.swift
@@ -0,0 +1,67 @@
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify
+
+// This file contains tests that test specific type checker functionality that
+// used to be in concurrent_value_checking.swift. This prevented other region
+// isolation errors from being emitted. We used to use multiple prefix tests to
+// validate aboth at the same time. Better to just split it.
+
+// REQUIRES: concurrency
+// REQUIRES: asserts
+
+class NotConcurrent { } // expected-note 3{{class 'NotConcurrent' does not conform to the 'Sendable' protocol}}
+
+@MainActor var booleanValue: Bool { false }
+
+actor TestActor {}
+
+@globalActor
+struct SomeGlobalActor {
+  static var shared: TestActor { TestActor() }
+}
+
+@SomeGlobalActor
+let globalValue: NotConcurrent? = nil
+
+@SomeGlobalActor
+func globalSync(_: NotConcurrent?) {
+}
+
+@SomeGlobalActor
+func globalAsync(_: NotConcurrent?) async {
+  if await booleanValue {
+    return
+  }
+  await globalAsync(globalValue) // both okay because we're in the actor
+  globalSync(nil)
+}
+
+enum E {
+  @SomeGlobalActor static let notSafe: NotConcurrent? = nil
+}
+
+func globalTest() async {
+  // expected-warning@+1 {{global actor 'SomeGlobalActor'-isolated let 'globalValue' cannot be accessed from outside of the actor}} {{11-11=await }}
+  let a = globalValue // expected-warning{{non-Sendable type 'NotConcurrent?' of let 'globalValue' cannot exit global actor 'SomeGlobalActor'-isolated context}}
+  await globalAsync(a)
+  await globalSync(a)
+
+  // expected-warning@+1 {{global actor 'SomeGlobalActor'-isolated static property 'notSafe' cannot be accessed from outside of the actor}} {{11-11=await }}
+  let _ = E.notSafe // expected-warning{{non-Sendable type 'NotConcurrent?' of static property 'notSafe' cannot exit global actor 'SomeGlobalActor'-isolated context}}
+
+  // expected-error@+3 {{expression is 'async' but is not marked with 'await'}}
+  // expected-note@+2 {{call is 'async'}}
+  // expected-note@+1 {{property access is 'async'}}
+  globalAsync(E.notSafe)
+
+  // expected-warning@-2 {{non-Sendable type 'NotConcurrent?' of static property 'notSafe' cannot exit global actor 'SomeGlobalActor'-isolated context}}
+}
+
+class C11 { }
+
+class C12: @unchecked C11 { } // expected-error {{'@unchecked' cannot apply to non-protocol type 'C11'}}
+
+protocol P { }
+
+protocol Q: @unchecked Sendable { } // expected-error {{'@unchecked' only applies in inheritance clauses}}
+
+typealias TypeAlias1 = @unchecked P // expected-error {{'@unchecked' only applies in inheritance clauses}}
diff --git a/test/Concurrency/concurrent_value_inference.swift b/test/Concurrency/concurrent_value_inference.swift
index a893da4336820..d098a82b8f082 100644
--- a/test/Concurrency/concurrent_value_inference.swift
+++ b/test/Concurrency/concurrent_value_inference.swift
@@ -1,8 +1,6 @@
 // RUN: %target-swift-frontend -enable-library-evolution -strict-concurrency=complete %s -emit-sil -o /dev/null -verify
-// RUN: %target-swift-frontend -enable-library-evolution -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 class C1 { } // expected-note {{class 'C1' does not conform to the 'Sendable' protocol}}
 final class C2: Sendable { }
diff --git a/test/Concurrency/concurrentfunction_capturediagnostics.swift b/test/Concurrency/concurrentfunction_capturediagnostics.swift
index 0d7c203c96a4e..5ca576d667943 100644
--- a/test/Concurrency/concurrentfunction_capturediagnostics.swift
+++ b/test/Concurrency/concurrentfunction_capturediagnostics.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -enable-experimental-flow-sensitive-concurrent-captures -verify -emit-sil %s -o - >/dev/null
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -enable-experimental-flow-sensitive-concurrent-captures -verify -emit-sil %s -o - >/dev/null -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -enable-experimental-flow-sensitive-concurrent-captures -verify -emit-sil %s -o - >/dev/null -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -enable-experimental-flow-sensitive-concurrent-captures -verify -emit-sil %s -o - >/dev/null -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 func f(_: @escaping @Sendable () -> Void) { }
 open class F {
diff --git a/test/Concurrency/custom_executor_enqueue_availability.swift b/test/Concurrency/custom_executor_enqueue_availability.swift
index ed01516f9921d..00ca75c17f098 100644
--- a/test/Concurrency/custom_executor_enqueue_availability.swift
+++ b/test/Concurrency/custom_executor_enqueue_availability.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend -enable-experimental-move-only %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -enable-experimental-move-only %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -enable-experimental-move-only %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -enable-experimental-move-only %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
 // REQUIRES: OS=macosx
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // rdar://106849189 move-only types should be supported in freestanding mode
 // UNSUPPORTED: freestanding
@@ -26,10 +24,12 @@ final class OldExecutorOldStdlib: SerialExecutor {
 /// availability, since in this case the UnownedJob version needs to exist.
 @available(SwiftStdlib 5.1, *)
 final class BothExecutorOldStdlib: SerialExecutor {
-  func enqueue(_ job: UnownedJob) {} // expected-note{{'enqueue' declared here}}
+  func enqueue(_ job: UnownedJob) {}
 
+  // This no longer warns, because of the use of StdlibDeploymentTarget in the
+  // runtime.
   @available(SwiftStdlib 5.9, *)
-  func enqueue(_ job: __owned ExecutorJob) {} // expected-warning{{'Executor.enqueue(ExecutorJob)' will never be used, due to the presence of 'enqueue(UnownedJob)'}}
+  func enqueue(_ job: __owned ExecutorJob) {}
 
   func asUnownedSerialExecutor() -> UnownedSerialExecutor {
     UnownedSerialExecutor(ordinary: self)
diff --git a/test/Concurrency/custom_executor_enqueue_deprecation_on_executor_extension.swift b/test/Concurrency/custom_executor_enqueue_deprecation_on_executor_extension.swift
index 5171ac257308e..8f79de92703e9 100644
--- a/test/Concurrency/custom_executor_enqueue_deprecation_on_executor_extension.swift
+++ b/test/Concurrency/custom_executor_enqueue_deprecation_on_executor_extension.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify %s
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=targeted %s
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=complete %s
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation %s
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // rdar://106849189 move-only types should be supported in freestanding mode
 // UNSUPPORTED: freestanding
diff --git a/test/Concurrency/custom_executor_enqueue_impls.swift b/test/Concurrency/custom_executor_enqueue_impls.swift
index efea9882fa586..a6b1a74bf1461 100644
--- a/test/Concurrency/custom_executor_enqueue_impls.swift
+++ b/test/Concurrency/custom_executor_enqueue_impls.swift
@@ -1,10 +1,8 @@
-// RUN: %target-swift-frontend -disable-availability-checking -emit-sil -o /dev/null -verify %s
-// RUN: %target-swift-frontend -disable-availability-checking -emit-sil -o /dev/null -verify -strict-concurrency=targeted %s
-// RUN: %target-swift-frontend -disable-availability-checking -emit-sil -o /dev/null -verify -strict-concurrency=complete %s
-// RUN: %target-swift-frontend -disable-availability-checking -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation %s
+// RUN: %target-swift-frontend -disable-availability-checking -emit-sil -o /dev/null -verify -verify-ignore-unrelated %s
+// RUN: %target-swift-frontend -disable-availability-checking -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=targeted %s
+// RUN: %target-swift-frontend -disable-availability-checking -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=complete %s
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // rdar://106849189 move-only types should be supported in freestanding mode
 // UNSUPPORTED: freestanding
diff --git a/test/Concurrency/default_actor_definit.swift b/test/Concurrency/default_actor_definit.swift
index 798a3240c36fd..94df91e853bfb 100644
--- a/test/Concurrency/default_actor_definit.swift
+++ b/test/Concurrency/default_actor_definit.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-sil %s  -target %target-swift-5.1-abi-triple | %FileCheck %s
 // RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-sil %s  -target %target-swift-5.1-abi-triple -strict-concurrency=targeted | %FileCheck %s
 // RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-sil %s  -target %target-swift-5.1-abi-triple -strict-concurrency=complete | %FileCheck %s
-// RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-sil %s  -target %target-swift-5.1-abi-triple -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation | %FileCheck %s
 
 // REQUIRES: concurrency
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 actor A {
   var x: String = "Hello"
diff --git a/test/Concurrency/default_isolation.swift b/test/Concurrency/default_isolation.swift
new file mode 100644
index 0000000000000..c1dbe2b895b7e
--- /dev/null
+++ b/test/Concurrency/default_isolation.swift
@@ -0,0 +1,58 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// REQUIRES: concurrency
+// REQUIRES: swift_feature_DefaultIsolationPerFile
+
+// RUN: %target-swift-frontend -enable-experimental-feature DefaultIsolationPerFile -emit-sil -swift-version 6 -disable-availability-checking %t/main.swift %t/concurrent.swift | %FileCheck %s
+
+//--- main.swift
+
+using @MainActor
+
+class C {
+  // CHECK: // static C.shared.getter
+  // CHECK-NEXT: // Isolation: global_actor. type: MainActor
+  static let shared = C()
+
+  // CHECK: // C.init()
+  // CHECK-NEXT: // Isolation: global_actor. type: MainActor
+  init() {}
+}
+
+// CHECK: // test()
+// CHECK-NEXT: // Isolation: global_actor. type: MainActor
+func test() {
+  // CHECK: // closure #1 in test()
+  // CHECK-NEXT: // Isolation: nonisolated
+  Task.detached {
+    let s = S(value: 0)
+  }
+}
+
+// Tested below. This used to fail in default-isolation mode because
+// the type-checker applied the default isolation to the implicit $defer
+// function, causing it to have MainActor isolation despite the enclosing
+// context being nonisolated.
+nonisolated func test_defer() {
+  defer {}
+}
+
+//--- concurrent.swift
+
+using nonisolated
+
+// CHECK: // S.init(value:)
+// CHECK-NEXT: // Isolation: unspecified
+struct S {
+  var value: Int
+}
+
+// CHECK: // test_defer()
+// CHECK-NEXT: // Isolation: nonisolated
+
+// CHECK: // $defer #1 () in test_defer()
+// CHECK-NEXT: // Isolation: nonisolated
+
+// CHECK: // S.value.getter
+// CHECK-NEXT: // Isolation: unspecified
diff --git a/test/Concurrency/deinit_isolation_availability.swift b/test/Concurrency/deinit_isolation_availability.swift
new file mode 100644
index 0000000000000..196ba61e37634
--- /dev/null
+++ b/test/Concurrency/deinit_isolation_availability.swift
@@ -0,0 +1,167 @@
+// RUN: %target-typecheck-verify-swift -swift-version 5 %s -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify-additional-prefix deployment- -verify-additional-prefix inlining-
+// RUN: %target-typecheck-verify-swift -swift-version 5 %s -strict-concurrency=complete -target %target-swift-6.1-abi-triple
+// RUN: %target-typecheck-verify-swift -swift-version 5 %s -strict-concurrency=complete -target %target-swift-6.1-abi-triple -target-min-inlining-version min -verify-additional-prefix inlining-
+
+// Test -emit-module configurations.
+
+// RUN: %target-swift-frontend -emit-module -verify -swift-version 5 %s -strict-concurrency=complete -target %target-swift-5.1-abi-triple -experimental-skip-non-inlinable-function-bodies -verify-additional-prefix inlining-
+// RUN: %target-swift-frontend -emit-module -verify -swift-version 5 %s -strict-concurrency=complete -target %target-swift-6.1-abi-triple -experimental-skip-non-inlinable-function-bodies -target-min-inlining-version min -verify-additional-prefix inlining-
+
+// REQUIRES: concurrency
+// REQUIRES: OS=macosx
+
+@MainActor class C {
+  var x: Int = 0
+
+  nonisolated deinit {
+    print(x)
+  }
+}
+
+@MainActor public class C1 {
+  var x: Int = 0
+
+  nonisolated deinit {
+    print(x)
+  }
+}
+
+@MainActor class C2 {
+  var x: Int = 0
+
+  isolated deinit { // okay, this back-deploys
+    print(x)
+  }
+}
+
+@MainActor public class C3 {
+  var x: Int = 0
+
+  isolated deinit { // okay, this back-deploys
+    print(x)
+  }
+}
+
+
+@available(SwiftStdlib 5.1, *)
+@globalActor
+public actor SomeGlobalActor {
+  public static let shared = SomeGlobalActor()
+}
+
+// expected-deployment-note@+1{{add '@available' attribute to enclosing class}}
+@SomeGlobalActor class C4 {
+  var x: Int = 0
+
+  isolated deinit { // expected-deployment-error{{isolated deinit is only available in macOS 15.4.0 or newer}}
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 6.1, *)
+@SomeGlobalActor class C5 {
+  var x: Int = 0
+
+  isolated deinit {
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+@SomeGlobalActor public class C6 {
+  var x: Int = 0
+
+  isolated deinit { // expected-deployment-error{{isolated deinit is only available in macOS 15.4.0 or newer}}
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 6.1, *)
+@SomeGlobalActor public class C7 {
+  var x: Int = 0
+
+  isolated deinit {
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+@_fixed_layout @SomeGlobalActor public class C8 {
+  @usableFromInline var x: Int = 0
+
+  @inlinable isolated deinit { // expected-inlining-error{{isolated deinit is only available in macOS 15.4.0 or newer}}
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 6.1, *)
+@_fixed_layout @SomeGlobalActor public class C9 {
+  @usableFromInline var x: Int = 0
+
+  @inlinable isolated deinit {
+    print(x)
+  }
+}
+
+// expected-deployment-note@+1{{add '@available' attribute to enclosing actor}}
+actor A {
+  var x: Int = 0
+
+  isolated deinit { // expected-deployment-error{{isolated deinit is only available in macOS 15.4.0 or newer}}
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+public actor A1 {
+  var x: Int = 0
+
+  isolated deinit { // expected-deployment-error{{isolated deinit is only available in macOS 15.4.0 or newer}}
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+public actor A2 {
+  @usableFromInline var x: Int = 0
+
+  @inlinable isolated deinit { // expected-inlining-error{{isolated deinit is only available in macOS 15.4.0 or newer}}
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 6.1, *)
+public actor A3 {
+  @usableFromInline var x: Int = 0
+
+  @inlinable isolated deinit {
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 6.1, *)
+actor A4 {
+  var x: Int = 0
+
+  isolated deinit {
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 6.1, *)
+public actor A5 {
+  var x: Int = 0
+
+  isolated deinit {
+    print(x)
+  }
+}
+
+@available(SwiftStdlib 6.1, *)
+public actor A6 {
+  @usableFromInline var x: Int = 0
+
+  @inlinable isolated deinit {
+    print(x)
+  }
+}
diff --git a/test/Concurrency/deinit_isolation_backdeploy.swift b/test/Concurrency/deinit_isolation_backdeploy.swift
new file mode 100644
index 0000000000000..99ebe9971228e
--- /dev/null
+++ b/test/Concurrency/deinit_isolation_backdeploy.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -parse-as-library -emit-silgen -DSILGEN %s | %FileCheck %s
+
+// REQUIRES: concurrency
+// REQUIRES: OS=macosx
+
+
+@MainActor
+class C {
+  // CHECK-LABEL: sil hidden [ossa] @$s27deinit_isolation_backdeploy1CCfD : $@convention(method) (@owned C) -> ()
+  // CHECK: function_ref @swift_task_deinitOnExecutorMainActorBackDeploy
+  isolated deinit { }
+}
+
+// Make sure this function is available
+// CHECK: sil hidden_external [serialized] [available 12.0.0] @swift_task_deinitOnExecutorMainActorBackDeploy : $@convention(thin) (@owned AnyObject, @convention(thin) (@owned AnyObject) -> (), Builtin.Executor, Builtin.Word) -> ()
diff --git a/test/Concurrency/deinit_isolation_import/test.swift b/test/Concurrency/deinit_isolation_import/test.swift
index f9894402df2ec..45cf6195e574e 100644
--- a/test/Concurrency/deinit_isolation_import/test.swift
+++ b/test/Concurrency/deinit_isolation_import/test.swift
@@ -1,16 +1,15 @@
 // RUN: %empty-directory(%t/Frameworks)
-// RUN: INPUT_DIR=%S/Inputs
-// RUN: cp -R $INPUT_DIR/Alpha.framework %t/Frameworks/
+// RUN: cp -R %S/Inputs/Alpha.framework %t/Frameworks/
 // RUN: %empty-directory(%t/Frameworks/Alpha.framework/Modules/Alpha.swiftmodule)
 // RUN: %empty-directory(%t/Frameworks/Alpha.framework/Headers/)
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-implicit-string-processing-module-import -parse-as-library -disable-availability-checking -module-name Alpha \
 // RUN:  -emit-module -o %t/Frameworks/Alpha.framework/Modules/Alpha.swiftmodule/%module-target-triple.swiftmodule \
 // RUN:  -enable-objc-interop -disable-objc-attr-requires-foundation-module \
-// RUN:  -emit-objc-header -emit-objc-header-path %t/Frameworks/Alpha.framework/Headers/Alpha-Swift.h $INPUT_DIR/Alpha.swift
-// RUN: cp -R $INPUT_DIR/Beta.framework %t/Frameworks/
+// RUN:  -emit-objc-header -emit-objc-header-path %t/Frameworks/Alpha.framework/Headers/Alpha-Swift.h %S/Inputs/Alpha.swift
+// RUN: cp -R %S/Inputs/Beta.framework %t/Frameworks/
 // RUN: %empty-directory(%t/Frameworks/Beta.framework/Headers/)
-// RUN: cp $INPUT_DIR/Beta.h %t/Frameworks/Beta.framework/Headers/Beta.h
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-implicit-string-processing-module-import -disable-availability-checking -typecheck -verify %s -F %t/Frameworks -F %clang-importer-sdk-path/frameworks
+// RUN: cp %S/Inputs/Beta.h %t/Frameworks/Beta.framework/Headers/Beta.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-implicit-string-processing-module-import -disable-availability-checking -typecheck -verify -verify-ignore-unrelated %s -F %t/Frameworks -F %clang-importer-sdk-path/frameworks
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-implicit-string-processing-module-import -disable-availability-checking -parse-as-library -emit-silgen -DSILGEN %s -F %t/Frameworks -F %clang-importer-sdk-path/frameworks | %FileCheck %s
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-implicit-string-processing-module-import -disable-availability-checking -parse-as-library -emit-silgen -DSILGEN %s -F %t/Frameworks -F %clang-importer-sdk-path/frameworks | %FileCheck -check-prefix=CHECK-SYMB %s
 
diff --git a/test/Concurrency/deinit_isolation_in_value_types.swift b/test/Concurrency/deinit_isolation_in_value_types.swift
index a97f75ac0d85e..8d876dfbbba08 100644
--- a/test/Concurrency/deinit_isolation_in_value_types.swift
+++ b/test/Concurrency/deinit_isolation_in_value_types.swift
@@ -19,7 +19,7 @@ struct CS: ~Copyable {
 }
 
 struct DS: ~Copyable {
-  nonisolated deinit {} // expected-error {{only classes and actors can have isolated deinit}}
+  nonisolated deinit {}
 }
 
 struct ES: ~Copyable {
@@ -47,7 +47,7 @@ enum CE: ~Copyable {
 enum DE: ~Copyable {
   case dummy
   // expected-error@+1 {{deinitializers are not yet supported on noncopyable enums}}
-  nonisolated deinit {} // expected-error {{only classes and actors can have isolated deinit}}
+  nonisolated deinit {}
 }
 
 enum EE: ~Copyable {
diff --git a/test/Concurrency/deinit_isolation_objc.swift b/test/Concurrency/deinit_isolation_objc.swift
index b7f46518eb30e..d32b62d258cd5 100644
--- a/test/Concurrency/deinit_isolation_objc.swift
+++ b/test/Concurrency/deinit_isolation_objc.swift
@@ -2,6 +2,9 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-implicit-string-processing-module-import -target %target-future-triple -parse-as-library -emit-silgen -DSILGEN %s | %FileCheck %s
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-implicit-string-processing-module-import -target %target-future-triple -parse-as-library -emit-silgen -DSILGEN %s | %FileCheck -check-prefix=CHECK-SYMB %s
 
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-implicit-string-processing-module-import -target %target-future-triple -parse-as-library -emit-module -DSILGEN -experimental-skip-non-inlinable-function-bodies-without-types %s
+
 // REQUIRES: concurrency
 // REQUIRES: objc_interop
 
diff --git a/test/Concurrency/derived_conformances_nonisolated.swift b/test/Concurrency/derived_conformances_nonisolated.swift
index 6c975ad5b060d..d42e64d95d9e3 100644
--- a/test/Concurrency/derived_conformances_nonisolated.swift
+++ b/test/Concurrency/derived_conformances_nonisolated.swift
@@ -1,9 +1,7 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -enable-upcoming-feature GlobalActorIsolatedTypesUsability
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation -enable-upcoming-feature GlobalActorIsolatedTypesUsability
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @MainActor
 struct X1: Equatable, Hashable, Codable {
diff --git a/test/Concurrency/dispatch_inference.swift b/test/Concurrency/dispatch_inference.swift
index 3884112b90a80..b92b75bd9650a 100644
--- a/test/Concurrency/dispatch_inference.swift
+++ b/test/Concurrency/dispatch_inference.swift
@@ -1,11 +1,8 @@
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %import-libdispatch -strict-concurrency=complete %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %import-libdispatch -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %import-libdispatch -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %import-libdispatch -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %import-libdispatch -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -verify-additional-prefix tns-
 
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 import Dispatch
 
@@ -27,8 +24,10 @@ func testUnsafeSendableInMainAsync() async {
   var x = 5
   DispatchQueue.main.async {
     x = 17 // expected-warning{{mutation of captured var 'x' in concurrently-executing code}}
+    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-tns-note @-2 {{'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
   }
-  print(x)
+  print(x) // expected-tns-note {{access can happen concurrently}}
 }
 
 func testUnsafeSendableInAsync(queue: DispatchQueue) async {
diff --git a/test/Concurrency/double_curry_thunk.swift b/test/Concurrency/double_curry_thunk.swift
new file mode 100644
index 0000000000000..ec12b91413441
--- /dev/null
+++ b/test/Concurrency/double_curry_thunk.swift
@@ -0,0 +1,21 @@
+// RUN: %target-swift-frontend -typecheck -strict-concurrency=complete -target %target-swift-5.1-abi-triple %s
+
+// REQUIRES: concurrency
+
+// We used to crash on this when processing double curry thunks. Make sure that
+// we do not do crash in the future.
+extension AsyncStream {
+  @Sendable func myCancel() {
+  }
+  func myNext2(_ continuation: UnsafeContinuation<Element?, Never>) {
+  }
+  func myNext() async -> Element? {
+    await withTaskCancellationHandler {
+      unsafe await withUnsafeContinuation {
+        unsafe myNext2($0)
+      }
+    } onCancel: { [myCancel] in
+      myCancel()
+    }
+  }
+}
diff --git a/test/Concurrency/dynamic_checks_for_func_refs_in_preconcurrency_apis.swift b/test/Concurrency/dynamic_checks_for_func_refs_in_preconcurrency_apis.swift
index f23320b16c65c..7a380f1ca8571 100644
--- a/test/Concurrency/dynamic_checks_for_func_refs_in_preconcurrency_apis.swift
+++ b/test/Concurrency/dynamic_checks_for_func_refs_in_preconcurrency_apis.swift
@@ -42,6 +42,10 @@ public struct S<T> {
   }
 }
 
+public class NS {}
+
+public func testNoIsolation(_: @escaping (NS) -> Void) {}
+
 //--- Client.swift
 import API
 
@@ -60,7 +64,7 @@ import API
 // CHECK-NEXT: [[OPTIONAL_TEST:%.*]] = enum $Optional<@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <Optional<Int>>>, #Optional.some!enumelt, [[CONVERTED_REABSTRACTED_TEST_REF]] :
 // CHECK-NEXT: // function_ref
 // CHECK-NEXT: [[COMPUTE_REF:%.*]] = function_ref @$s3API7computeyyyxcSglF : $@convention(thin) <τ_0_0> (@guaranteed Optional<@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0>>) -> ()
-// CHECK-NEXT: {{.*}} = apply [[COMPUTE_REF]]<Int?>([[OPTIONAL_TEST]]) : $@convention(thin) <τ_0_0> (@guaranteed Optional<@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0>>) -> ()
+// CHECK-NEXT: {{.*}} = apply [[COMPUTE_REF]]<Optional<Int>>([[OPTIONAL_TEST]]) : $@convention(thin) <τ_0_0> (@guaranteed Optional<@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0>>) -> ()
 @MainActor
 func testMainActorContext() {
   compute(test) // no warning
@@ -164,3 +168,14 @@ func testMembers<X>(v: X, s: S<X>, fn: @escaping @MainActor (X) -> Int) {
 // CHECK-NEXT: [[EXEC:%.*]] = extract_executor [[MAIN_ACTOR_ACCESS]] : $MainActor
 // CHECK: [[CHECK_EXEC_REF:%.*]] = function_ref @$ss22_checkExpectedExecutor14_filenameStart01_D6Length01_D7IsASCII5_line9_executoryBp_BwBi1_BwBetF
 // CHECK-NEXT: {{.*}} = apply [[CHECK_EXEC_REF]]({{.*}}, [[EXEC]])
+
+@MainActor
+class Test {
+  @Sendable func compute(_: NS) {}
+  // expected-warning@-1 {{main actor-isolated synchronous instance method 'compute' cannot be marked as '@Sendable'; this is an error in the Swift 6 language mode}}
+
+  func test() {
+    // Triggers loss of @Sendable and actor isolation erasure at the same time
+    testNoIsolation(compute)
+  }
+}
diff --git a/test/Concurrency/experimental_feature_strictconcurrency_targeted.swift b/test/Concurrency/experimental_feature_strictconcurrency_targeted.swift
index 8bf8237c35045..b054daf8c8e2f 100644
--- a/test/Concurrency/experimental_feature_strictconcurrency_targeted.swift
+++ b/test/Concurrency/experimental_feature_strictconcurrency_targeted.swift
@@ -2,10 +2,8 @@
 // RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -verify-additional-prefix complete- -strict-concurrency=complete
 // RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -verify-additional-prefix complete- -enable-experimental-feature StrictConcurrency
 // RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -verify-additional-prefix complete- -enable-experimental-feature StrictConcurrency=targeted -enable-experimental-feature StrictConcurrency=complete
-// RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -verify-additional-prefix complete- -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 // REQUIRES: swift_feature_StrictConcurrency
 
 class C { // expected-note {{class 'C' does not conform to the 'Sendable' protocol}}
diff --git a/test/Concurrency/flow_isolation.swift b/test/Concurrency/flow_isolation.swift
index 3ecba4c5d6f6b..da728f2f973f6 100644
--- a/test/Concurrency/flow_isolation.swift
+++ b/test/Concurrency/flow_isolation.swift
@@ -1,7 +1,5 @@
 // RUN: %target-swift-frontend -strict-concurrency=complete -swift-version 5 -parse-as-library -emit-sil -verify %s
-// RUN: %target-swift-frontend -strict-concurrency=complete -swift-version 5 -parse-as-library -emit-sil -verify %s -enable-upcoming-feature RegionBasedIsolation
 
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 func randomBool() -> Bool { return false }
 func logTransaction(_ i: Int) {}
@@ -128,7 +126,7 @@ actor Demons {
   }
 
   deinit {
-    let _ = self.ns // expected-warning {{cannot access property 'ns' with a non-sendable type 'NonSendableType' from nonisolated deinit; this is an error in the Swift 6 language mode}}
+    let _ = self.ns // expected-warning {{cannot access property 'ns' with a non-Sendable type 'NonSendableType' from nonisolated deinit; this is an error in the Swift 6 language mode}}
   }
 }
 
@@ -161,13 +159,13 @@ actor ExampleFromProposal {
   deinit {
     _ = self.immutableSendable  // ok
     _ = self.mutableSendable    // ok
-    _ = self.nonSendable        // expected-warning {{cannot access property 'nonSendable' with a non-sendable type 'NonSendableType' from nonisolated deinit; this is an error in the Swift 6 language mode}}
+    _ = self.nonSendable        // expected-warning {{cannot access property 'nonSendable' with a non-Sendable type 'NonSendableType' from nonisolated deinit; this is an error in the Swift 6 language mode}}
 
     f() // expected-note {{after calling instance method 'f()', only nonisolated properties of 'self' can be accessed from a deinit}}
 
     _ = self.immutableSendable  // ok
     _ = self.mutableSendable    // expected-warning {{cannot access property 'mutableSendable' here in deinitializer; this is an error in the Swift 6 language mode}}
-    _ = self.nonSendable        // expected-warning {{cannot access property 'nonSendable' with a non-sendable type 'NonSendableType' from nonisolated deinit; this is an error in the Swift 6 language mode}}
+    _ = self.nonSendable        // expected-warning {{cannot access property 'nonSendable' with a non-Sendable type 'NonSendableType' from nonisolated deinit; this is an error in the Swift 6 language mode}}
   }
 
   nonisolated func f() {}
@@ -199,7 +197,7 @@ class CheckGAIT1 {
   }
 
   deinit {
-    _ = ns // expected-warning {{cannot access property 'ns' with a non-sendable type 'NonSendableType' from nonisolated deinit; this is an error in the Swift 6 language mode}}
+    _ = ns // expected-warning {{cannot access property 'ns' with a non-Sendable type 'NonSendableType' from nonisolated deinit; this is an error in the Swift 6 language mode}}
     f()     // expected-note {{after calling instance method 'f()', only nonisolated properties of 'self' can be accessed from a deinit}}
     _ = silly // expected-warning {{cannot access property 'silly' here in deinitializer; this is an error in the Swift 6 language mode}}
 
@@ -733,8 +731,8 @@ actor OhBrother {
 class CheckDeinitFromClass: AwesomeUIView {
   var ns: NonSendableType?
   deinit {
-    ns?.f() // expected-warning {{cannot access property 'ns' with a non-sendable type 'NonSendableType?' from nonisolated deinit; this is an error in the Swift 6 language mode}}
-    ns = nil // expected-warning {{cannot access property 'ns' with a non-sendable type 'NonSendableType?' from nonisolated deinit; this is an error in the Swift 6 language mode}}
+    ns?.f() // expected-warning {{cannot access property 'ns' with a non-Sendable type 'NonSendableType?' from nonisolated deinit; this is an error in the Swift 6 language mode}}
+    ns = nil // expected-warning {{cannot access property 'ns' with a non-Sendable type 'NonSendableType?' from nonisolated deinit; this is an error in the Swift 6 language mode}}
   }
 }
 
@@ -742,8 +740,8 @@ class CheckDeinitFromClass: AwesomeUIView {
 actor CheckDeinitFromActor {
   var ns: NonSendableType?
   deinit {
-    ns?.f() // expected-warning {{cannot access property 'ns' with a non-sendable type 'NonSendableType?' from nonisolated deinit; this is an error in the Swift 6 language mode}}
-    ns = nil // expected-warning {{cannot access property 'ns' with a non-sendable type 'NonSendableType?' from nonisolated deinit; this is an error in the Swift 6 language mode}}
+    ns?.f() // expected-warning {{cannot access property 'ns' with a non-Sendable type 'NonSendableType?' from nonisolated deinit; this is an error in the Swift 6 language mode}}
+    ns = nil // expected-warning {{cannot access property 'ns' with a non-Sendable type 'NonSendableType?' from nonisolated deinit; this is an error in the Swift 6 language mode}}
   }
 }
 
diff --git a/test/Concurrency/flow_isolation_nonstrict.swift b/test/Concurrency/flow_isolation_nonstrict.swift
index 96a101cd25a5f..7a4c0cb9b29af 100644
--- a/test/Concurrency/flow_isolation_nonstrict.swift
+++ b/test/Concurrency/flow_isolation_nonstrict.swift
@@ -7,7 +7,7 @@ class NonSendableType {
 }
 
 // rdar://94699928 - don't emit sendable diagnostics in non-'complete' mode
-// for deinits of actor or global-actor isolated types
+// for deinits of actor- or global-actor-isolated types
 
 @available(SwiftStdlib 5.1, *)
 @MainActor class AwesomeUIView {}
diff --git a/test/Concurrency/global_actor_from_ordinary_context.swift b/test/Concurrency/global_actor_from_ordinary_context.swift
index ad713a0d614e0..eb28b1db929e0 100644
--- a/test/Concurrency/global_actor_from_ordinary_context.swift
+++ b/test/Concurrency/global_actor_from_ordinary_context.swift
@@ -1,6 +1,6 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify-additional-prefix minimal-and-targeted- -verify
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify-additional-prefix minimal-and-targeted- -verify -strict-concurrency=targeted
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify-additional-prefix complete-and-tns- -verify -strict-concurrency=complete
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify-additional-prefix complete- -verify -strict-concurrency=complete
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
@@ -36,15 +36,15 @@ func referenceGlobalActor() async {
   let a = Alex()
   _ = a.method
   _ = a.const_memb
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-  _ = a.mut_memb // expected-note{{property access is 'async'}}
+  // expected-error@+1{{global actor 'SomeGlobalActor'-isolated property 'mut_memb' cannot be accessed from outside of the actor}}{{7-7=await }}
+  _ = a.mut_memb
 
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-  _ = a[1]  // expected-note{{subscript access is 'async'}}
+  // expected-error@+1{{global actor 'SomeGlobalActor'-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}}{{7-7=await }}
+  _ = a[1]
   a[0] = 1  // expected-error{{global actor 'SomeGlobalActor'-isolated subscript 'subscript(_:)' can not be mutated from a nonisolated context}}
 
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-  _ = 32 + a[1] // expected-note@:12{{subscript access is 'async'}}
+  // expected-error@+1{{global actor 'SomeGlobalActor'-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}}{{7-7=await }}
+  _ = 32 + a[1]
 }
 
 
@@ -122,17 +122,16 @@ func fromAsync() async {
   fn() // expected-error{{expression is 'async' but is not marked with 'await'}}
   // expected-note@-1{{calls to let 'fn' from outside of its actor context are implicitly asynchronous}}
   _ = a.const_memb
-  _ = a.mut_memb  // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{property access is 'async'}}
+  _ = a.mut_memb  // expected-error{{global actor 'SomeGlobalActor'-isolated property 'mut_memb' cannot be accessed from outside of the actor}} {{7-7=await }}
 
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
-  _ = a[1]  // expected-note{{subscript access is 'async'}}
+  // expected-error@+1{{global actor 'SomeGlobalActor'-isolated subscript 'subscript(_:)' cannot be accessed from outside of the actor}}{{7-7=await }}
+  _ = a[1]
   _ = await a[1]
   a[0] = 1  // expected-error{{global actor 'SomeGlobalActor'-isolated subscript 'subscript(_:)' can not be mutated from a nonisolated context}}
 }
 
 // expected-minimal-and-targeted-note @+2 {{mutation of this var is only permitted within the actor}}
-// expected-complete-and-tns-error @+1 {{top-level code variables cannot have a global actor}}
+// expected-complete-error @+1 {{top-level code variables cannot have a global actor}}
 @SomeGlobalActor var value: Int = 42
 
 func topLevelSyncFunction(_ number: inout Int) { }
@@ -144,7 +143,6 @@ topLevelSyncFunction(&value)
 
 class Sub: Super {
   func f() { }
-  // expected-note@-1 {{global actor 'SomeGlobalActor' isolation inferred from inheritance from class 'Super'}}
 
   func g() {
     Task.detached {
@@ -154,8 +152,7 @@ class Sub: Super {
 
   func g2() {
     Task.detached {
-      self.f() // expected-warning{{expression is 'async' but is not marked with 'await'}}
-      // expected-note@-1{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+      self.f() // expected-warning{{global actor 'SomeGlobalActor'-isolated instance method 'f()' cannot be called from outside of the actor}} {{7-7=await }}
     }
   }
 }
diff --git a/test/Concurrency/global_actor_function_types.swift b/test/Concurrency/global_actor_function_types.swift
index d3c3f7ad2ee72..a41a5b97c8672 100644
--- a/test/Concurrency/global_actor_function_types.swift
+++ b/test/Concurrency/global_actor_function_types.swift
@@ -7,8 +7,8 @@
 // Emit SIL with targeted concurrency.
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted -verify-additional-prefix without-transferring-
 
-// Emit SIL with strict concurrency + region based isolation + transferring
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete  -verify-additional-prefix complete-tns-
+// Emit SIL with strict concurrency + region-based isolation + transferring
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete  -verify-additional-prefix complete-
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
@@ -38,7 +38,7 @@ func testConversions(f: @escaping @SomeGlobalActor (Int) -> Void, g: @escaping (
 
 @OtherGlobalActor func onOtherGlobalActor() -> Int { 5 } // expected-note{{calls to global function 'onOtherGlobalActor()' from outside of its actor context are implicitly asynchronous}}
 @preconcurrency @OtherGlobalActor func onOtherGlobalActorUnsafe() -> Int { 5 }  // expected-note 2{{calls to global function 'onOtherGlobalActorUnsafe()' from outside of its actor context are implicitly asynchronous}}
-// expected-complete-tns-note @-1 {{calls to global function 'onOtherGlobalActorUnsafe()' from outside of its actor context are implicitly asynchronous}}
+// expected-complete-note @-1 {{calls to global function 'onOtherGlobalActorUnsafe()' from outside of its actor context are implicitly asynchronous}}
 
 func someSlowOperation() async -> Int { 5 }
 
@@ -99,7 +99,7 @@ func testClosuresOld() {
   }
 
   acceptOnSomeGlobalActor { () -> Int in
-    let i = onOtherGlobalActorUnsafe() // expected-complete-tns-warning {{call to global actor 'OtherGlobalActor'-isolated global function 'onOtherGlobalActorUnsafe()' in a synchronous global actor 'SomeGlobalActor'-isolated context}}
+    let i = onOtherGlobalActorUnsafe() // expected-complete-warning {{call to global actor 'OtherGlobalActor'-isolated global function 'onOtherGlobalActorUnsafe()' in a synchronous global actor 'SomeGlobalActor'-isolated context}}
     return i
   }
 
@@ -129,16 +129,16 @@ func g2(_ x: X<() -> Void>) {
 
 
 func testTypesNonConcurrencyContext() { // expected-note{{add '@SomeGlobalActor' to make global function 'testTypesNonConcurrencyContext()' part of global actor 'SomeGlobalActor'}}
-  // expected-complete-tns-note @-1 {{add '@SomeGlobalActor' to make global function 'testTypesNonConcurrencyContext()' part of global actor 'SomeGlobalActor'}}
+  // expected-complete-note @-1 {{add '@SomeGlobalActor' to make global function 'testTypesNonConcurrencyContext()' part of global actor 'SomeGlobalActor'}}
   let f1 = onSomeGlobalActor // expected-note{{calls to let 'f1' from outside of its actor context are implicitly asynchronous}}
-  let f2 = onSomeGlobalActorUnsafe // expected-complete-tns-note {{calls to let 'f2' from outside of its actor context are implicitly asynchronous}}
+  let f2 = onSomeGlobalActorUnsafe // expected-complete-note {{calls to let 'f2' from outside of its actor context are implicitly asynchronous}}
 
   let _: () -> Int = f1 // expected-warning {{converting function value of type '@SomeGlobalActor () -> Int' to '() -> Int' loses global actor 'SomeGlobalActor'}}
-  let _: () -> Int = f2 // expected-complete-tns-warning {{converting function value of type '@SomeGlobalActor () -> Int' to '() -> Int' loses global actor 'SomeGlobalActor'}}
+  let _: () -> Int = f2 // expected-complete-warning {{converting function value of type '@SomeGlobalActor () -> Int' to '() -> Int' loses global actor 'SomeGlobalActor'}}
 
   _ = {
     let _: () -> Int = f1 // expected-warning {{converting function value of type '@SomeGlobalActor () -> Int' to '() -> Int' loses global actor 'SomeGlobalActor'}}
-    let _: () -> Int = f2 // expected-complete-tns-warning {{converting function value of type '@SomeGlobalActor () -> Int' to '() -> Int' loses global actor 'SomeGlobalActor'}}
+    let _: () -> Int = f2 // expected-complete-warning {{converting function value of type '@SomeGlobalActor () -> Int' to '() -> Int' loses global actor 'SomeGlobalActor'}}
   }
 
   @SomeGlobalActor func isolated() {
@@ -147,7 +147,7 @@ func testTypesNonConcurrencyContext() { // expected-note{{add '@SomeGlobalActor'
   }
 
   _ = f1() // expected-error{{call to global actor 'SomeGlobalActor'-isolated let 'f1' in a synchronous nonisolated context}}
-  _ = f2() // expected-complete-tns-error {{call to global actor 'SomeGlobalActor'-isolated let 'f2' in a synchronous nonisolated context}}
+  _ = f2() // expected-complete-error {{call to global actor 'SomeGlobalActor'-isolated let 'f2' in a synchronous nonisolated context}}
 }
 
 func testTypesConcurrencyContext() async {
@@ -328,7 +328,7 @@ func stripActor(_ expr: @Sendable @autoclosure () -> (() -> ())) async {
 }
 
 // We used to not emit an error here with strict-concurrency enabled since we
-// were inferring the async let to main actor isolated (which was incorrect). We
+// were inferring the async let to MainActor isolated (which was incorrect). We
 // now always treat async let as non-isolated, so we get the same error in all
 // contexts.
 @MainActor func exampleWhereConstraintSolverHasWrongDeclContext_v2() async -> Int {
@@ -408,7 +408,7 @@ struct GlobalType {}
 
 @_Concurrency.MainActor
 extension GlobalType {
-  @_Concurrency.MainActor static func ==(
+  @Swift.MainActor static func ==(
     lhs: GlobalType,
     rhs: GlobalType
   ) -> Bool { true }
diff --git a/test/Concurrency/global_actor_function_types_swift6.swift b/test/Concurrency/global_actor_function_types_swift6.swift
new file mode 100644
index 0000000000000..2d422c06c6eb4
--- /dev/null
+++ b/test/Concurrency/global_actor_function_types_swift6.swift
@@ -0,0 +1,15 @@
+// RUN: %target-typecheck-verify-swift  -target %target-swift-5.1-abi-triple -language-mode 6
+
+final class NonSendable {
+}
+
+@available(*, unavailable)
+extension NonSendable: Sendable {}
+
+actor Test {
+  func testNonSendableCrossingIsolationinAsync(v: NonSendable) {
+    let _: () async -> NonSendable = { @MainActor in v }
+    // expected-error@-1 {{cannot convert '@MainActor @Sendable () async -> NonSendable' to '() async -> NonSendable' because crossing of an isolation boundary requires parameter and result types to conform to 'Sendable' protocol}}
+    // expected-note@-2 {{type 'NonSendable' does not conform to 'Sendable' protocol}}
+  }
+}
diff --git a/test/Concurrency/global_actor_inference.swift b/test/Concurrency/global_actor_inference.swift
index d76b30c13a177..9c409b3027bd0 100644
--- a/test/Concurrency/global_actor_inference.swift
+++ b/test/Concurrency/global_actor_inference.swift
@@ -3,12 +3,10 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/other_global_actor_inference.swiftmodule -module-name other_global_actor_inference -strict-concurrency=complete %S/Inputs/other_global_actor_inference.swift -enable-upcoming-feature GlobalActorIsolatedTypesUsability
 // RUN: %target-swift-frontend -I %t -disable-availability-checking %s -emit-sil -o /dev/null -verify -verify-additional-prefix minimal-targeted- -enable-upcoming-feature GlobalActorIsolatedTypesUsability
 // RUN: %target-swift-frontend -I %t -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted -verify-additional-prefix minimal-targeted- -enable-upcoming-feature GlobalActorIsolatedTypesUsability
-// RUN: %target-swift-frontend -I %t -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -verify-additional-prefix complete-tns- -enable-upcoming-feature GlobalActorIsolatedTypesUsability
-// RUN: %target-swift-frontend -I %t -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation -verify-additional-prefix complete-tns- -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -I %t -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -verify-additional-prefix complete- -enable-upcoming-feature GlobalActorIsolatedTypesUsability
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 import other_global_actor_inference
 
@@ -127,6 +125,7 @@ protocol Interface {
 @MainActor
 class Object: Interface {
   // expected-note@-1{{turn data races into runtime errors with '@preconcurrency'}}{{15-15=@preconcurrency }}
+  // expected-note@-2{{isolate this conformance to the main actor with '@MainActor'}}
 
   var baz: Int = 42 // expected-note{{main actor-isolated property 'baz' cannot satisfy nonisolated requirement}}
 }
@@ -281,8 +280,8 @@ class SubclassWithGlobalActors : SuperclassWithGlobalActors {
 @SomeGlobalActor func sibling() { foo() }
 
 func bar() async {
-  // expected-error@+1{{expression is 'async' but is not marked with 'await'}}{{3-3=await }}
-  foo() // expected-note{{calls to global function 'foo()' from outside of its actor context are implicitly asynchronous}}
+  // expected-error@+1{{global actor 'SomeGlobalActor'-isolated global function 'foo()' cannot be called from outside of the actor}}{{3-3=await }}
+  foo()
 }
 
 // expected-note@+1 {{add '@SomeGlobalActor' to make global function 'barSync()' part of global actor 'SomeGlobalActor'}} {{1-1=@SomeGlobalActor }}
@@ -401,8 +400,7 @@ struct HasWrapperOnActor {
     synced = 17
   }
 
-  @WrapperActor var actorSynced: Int = 0 // expected-warning{{'nonisolated' is not supported on properties with property wrappers}}
-
+  @WrapperActor var actorSynced: Int = 0 // expected-warning {{'nonisolated' cannot be applied to mutable stored properties}}
   func testActorSynced() {
     _ = actorSynced
     _ = $actorSynced
@@ -456,7 +454,7 @@ actor ActorWithWrapper {
   @WrapperOnActor var synced: Int = 0
   // expected-note@-1 3{{property declared here}}
   @WrapperWithMainActorDefaultInit var property: Int // expected-minimal-targeted-error {{call to main actor-isolated initializer 'init()' in a synchronous actor-isolated context}}
-  // expected-complete-tns-warning@-1 {{main actor-isolated default value in a actor-isolated context; this is an error in the Swift 6 language mode}}
+  // expected-complete-warning@-1 {{main actor-isolated default value in a actor-isolated context; this is an error in the Swift 6 language mode}}
   func f() {
     _ = synced // expected-error{{main actor-isolated property 'synced' can not be referenced on a different actor instance}}
     _ = $synced // expected-error{{global actor 'SomeGlobalActor'-isolated property '$synced' can not be referenced on a different actor instance}}
@@ -500,9 +498,8 @@ struct SimplePropertyWrapper {
 
 @MainActor
 class WrappedContainsNonisolatedAttr {
-  @SimplePropertyWrapper nonisolated var value 
-  // expected-error@-1 {{'nonisolated' is not supported on properties with property wrappers}}
-  // expected-note@-2 {{property declared here}}
+  @SimplePropertyWrapper nonisolated var value
+  // expected-note@-1 {{property declared here}}
 
   nonisolated func test() {
     _ = value
@@ -573,18 +570,18 @@ struct WrapperOnUnsafeActor<Wrapped> {
 // HasWrapperOnUnsafeActor does not have an inferred global actor attribute,
 // because synced and $synced have different global actors.
 struct HasWrapperOnUnsafeActor {
-// expected-complete-tns-warning@-1 {{memberwise initializer for 'HasWrapperOnUnsafeActor' cannot be both nonisolated and global actor 'OtherGlobalActor'-isolated; this is an error in the Swift 6 language mode}}
-// expected-complete-tns-warning@-2 {{default initializer for 'HasWrapperOnUnsafeActor' cannot be both nonisolated and global actor 'OtherGlobalActor'-isolated; this is an error in the Swift 6 language mode}}
+// expected-complete-warning@-1 {{memberwise initializer for 'HasWrapperOnUnsafeActor' cannot be both nonisolated and global actor 'OtherGlobalActor'-isolated; this is an error in the Swift 6 language mode}}
+// expected-complete-warning@-2 {{default initializer for 'HasWrapperOnUnsafeActor' cannot be both nonisolated and global actor 'OtherGlobalActor'-isolated; this is an error in the Swift 6 language mode}}
 
-  @WrapperOnUnsafeActor var synced: Int = 0 // expected-complete-tns-note 2 {{initializer for property '_synced' is global actor 'OtherGlobalActor'-isolated}}
+  @WrapperOnUnsafeActor var synced: Int = 0 // expected-complete-note 2 {{initializer for property '_synced' is global actor 'OtherGlobalActor'-isolated}}
   // expected-note @-1 2{{property declared here}}
-  // expected-complete-tns-note @-2 2{{property declared here}}
+  // expected-complete-note @-2 2{{property declared here}}
 
   func testUnsafeOkay() {
-    // expected-complete-tns-note @-1 {{add '@SomeGlobalActor' to make instance method 'testUnsafeOkay()' part of global actor 'SomeGlobalActor'}}
-    // expected-complete-tns-note @-2 {{add '@MainActor' to make instance method 'testUnsafeOkay()' part of global actor 'MainActor'}}
-    _ = synced // expected-complete-tns-warning {{main actor-isolated property 'synced' can not be referenced from a nonisolated context}}
-    _ = $synced // expected-complete-tns-warning {{global actor 'SomeGlobalActor'-isolated property '$synced' can not be referenced from a nonisolated context}}
+    // expected-complete-note @-1 {{add '@SomeGlobalActor' to make instance method 'testUnsafeOkay()' part of global actor 'SomeGlobalActor'}}
+    // expected-complete-note @-2 {{add '@MainActor' to make instance method 'testUnsafeOkay()' part of global actor 'MainActor'}}
+    _ = synced // expected-complete-warning {{main actor-isolated property 'synced' can not be referenced from a nonisolated context}}
+    _ = $synced // expected-complete-warning {{global actor 'SomeGlobalActor'-isolated property '$synced' can not be referenced from a nonisolated context}}
     _ = _synced // okay
   }
 
@@ -644,8 +641,7 @@ func acceptAsyncSendableClosureInheriting<T>(@_inheritActorContext _: @Sendable
 
 @MainActor func testCallFromMainActor() {
   acceptAsyncSendableClosure {
-    onlyOnMainActor() // expected-error{{expression is 'async' but is not marked with 'await'}}
-    // expected-note@-1 {{calls to global function 'onlyOnMainActor()' from outside of its actor context are implicitly asynchronous}}
+    onlyOnMainActor() // expected-error{{main actor-isolated global function 'onlyOnMainActor()' cannot be called from outside of the actor}} {{5-5=await }}
   }
 
   acceptAsyncSendableClosure {
@@ -665,7 +661,7 @@ func acceptAsyncSendableClosureInheriting<T>(@_inheritActorContext _: @Sendable
 // defer bodies inherit global actor-ness
 @MainActor
 var statefulThingy: Bool = false // expected-minimal-targeted-note {{var declared here}}
-// expected-complete-tns-error @-1 {{top-level code variables cannot have a global actor}}
+// expected-complete-error @-1 {{top-level code variables cannot have a global actor}}
 
 @MainActor
 func useFooInADefer() -> String { // expected-minimal-targeted-note {{calls to global function 'useFooInADefer()' from outside of its actor context are implicitly asynchronous}}
@@ -688,9 +684,9 @@ func replacesDynamicOnMainActor() {
 // Global-actor isolation of stored property initializer expressions
 // ----------------------------------------------------------------------
 
-// expected-complete-tns-warning@+1 {{default initializer for 'Cutter' cannot be both nonisolated and main actor-isolated; this is an error in the Swift 6 language mode}}
+// expected-complete-warning@+1 {{default initializer for 'Cutter' cannot be both nonisolated and main actor-isolated; this is an error in the Swift 6 language mode}}
 class Cutter {
-  // expected-complete-tns-note@+1 {{initializer for property 'x' is main actor-isolated}}
+  // expected-complete-note@+1 {{initializer for property 'x' is main actor-isolated}}
   @MainActor var x = useFooInADefer()
   @MainActor var y = { () -> Bool in
       var z = statefulThingy
@@ -701,10 +697,10 @@ class Cutter {
 @SomeGlobalActor
 class Butter {
   var a = useFooInADefer() // expected-minimal-targeted-error {{call to main actor-isolated global function 'useFooInADefer()' in a synchronous global actor 'SomeGlobalActor'-isolated context}}
-  // expected-complete-tns-warning@-1 {{main actor-isolated default value in a global actor 'SomeGlobalActor'-isolated context; this is an error in the Swift 6 language mode}}
+  // expected-complete-warning@-1 {{main actor-isolated default value in a global actor 'SomeGlobalActor'-isolated context; this is an error in the Swift 6 language mode}}
 
   nonisolated let b = statefulThingy // expected-minimal-targeted-error {{main actor-isolated var 'statefulThingy' can not be referenced from a nonisolated context}}
-  // expected-complete-tns-warning@-1 {{main actor-isolated default value in a nonisolated context; this is an error in the Swift 6 language mode}}
+  // expected-complete-warning@-1 {{main actor-isolated default value in a nonisolated context; this is an error in the Swift 6 language mode}}
 
   var c: Int = {
     return getGlobal7()
diff --git a/test/Concurrency/global_actor_inference_swift6.swift b/test/Concurrency/global_actor_inference_swift6.swift
index fb795a446a35e..df8f4e5abd6fd 100644
--- a/test/Concurrency/global_actor_inference_swift6.swift
+++ b/test/Concurrency/global_actor_inference_swift6.swift
@@ -115,7 +115,7 @@ struct HasWrapperOnActor {
     synced = 17
   }
 
-  @WrapperActor var actorSynced: Int = 0 // expected-error{{'nonisolated' is not supported on properties with property wrappers}}
+  @WrapperActor var actorSynced: Int = 0 // expected-error {{'nonisolated' cannot be applied to mutable stored properties}}
 
   func testActorSynced() {
     _ = actorSynced
@@ -207,6 +207,7 @@ protocol InferenceConflictWithSuperclass: MainActorSuperclass, InferSomeGlobalAc
 class C2: MainActorSuperclass, InferenceConflictWithSuperclass {
   //expected-note@-1 {{turn data races into runtime errors with '@preconcurrency'}}
   // expected-note@-2{{mark all declarations used in the conformance 'nonisolated'}}
+  // expected-note@-3{{isolate this conformance to the main actor with '@MainActor'}}
 
   func f() {}
 
@@ -223,5 +224,5 @@ class InheritConformance: ConformInExtension {
 }
 
 func testInheritedMainActorConformance() {
-  InheritConformance().f() // okay; this is not main actor isolated
+  InheritConformance().f() // okay; this is not MainActor isolated
 }
diff --git a/test/Concurrency/global_actor_isolated_completion_handlers.swift b/test/Concurrency/global_actor_isolated_completion_handlers.swift
new file mode 100644
index 0000000000000..f3e4dd4079712
--- /dev/null
+++ b/test/Concurrency/global_actor_isolated_completion_handlers.swift
@@ -0,0 +1,102 @@
+// RUN: %empty-directory(%t/src)
+// RUN: %empty-directory(%t/sdk)
+// RUN: split-file %s %t/src
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %t/src/main.swift \
+// RUN:   -import-objc-header %t/src/Test.h \
+// RUN:   -swift-version 6 \
+// RUN:   -module-name main -I %t -verify -verify-ignore-unrelated
+
+// REQUIRES: objc_interop
+
+//--- Test.h
+#define SWIFT_SENDABLE __attribute__((__swift_attr__("@Sendable")))
+#define NONSENDABLE __attribute__((__swift_attr__("@_nonSendable")))
+#define MAIN_ACTOR __attribute__((__swift_attr__("@MainActor")))
+
+#pragma clang assume_nonnull begin
+
+@import Foundation;
+
+MAIN_ACTOR
+@protocol P <NSObject>
+@end
+
+@interface TestFromProtocol <P>
+-(void) compute: (void (^)(void)) completion;
+@end
+
+MAIN_ACTOR
+@interface TestFromType <NSObject>
+-(void) compute: (void (^)(void)) completion;
+@end
+
+@interface TestSubclass : TestFromType
+-(void) subCompute: (void (^)(void)) completion;
+@end
+
+@interface TestFromMethod <NSObject>
+-(void) MAIN_ACTOR compute: (void (^)(void)) completion;
++(void) MAIN_ACTOR computeStatic: (void (^)(void)) completion;
+@end
+
+#pragma clang assume_nonnull end
+
+//--- main.swift
+
+func testFromProtocol(v: TestFromProtocol) {
+  let _: Int = v.compute
+  // expected-error@-1 {{cannot convert value of type '@MainActor @Sendable (@escaping () -> Void) -> Void' to specified type 'Int'}}
+}
+
+func testFromType(v: TestFromType) {
+  let _: Int = v.compute
+  // expected-error@-1 {{annot convert value of type '@MainActor @Sendable (@escaping () -> Void) -> Void' to specified type 'Int'}}
+}
+
+func testFromSuperclass(v: TestSubclass) {
+  let _: Int = v.subCompute
+  // expected-error@-1 {{cannot convert value of type '@MainActor @Sendable (@escaping () -> Void) -> Void' to specified type 'Int'}}
+}
+
+func testFromMethod(v: TestFromMethod, t: TestFromMethod.Type) {
+  let _: Int = v.compute
+  // expected-error@-1 {{cannot convert value of type '@MainActor (@escaping () -> Void) -> Void' to specified type 'Int'}}
+
+  let _: Int = t.computeStatic
+  // expected-error@-1 {{cannot convert value of type '@MainActor @Sendable (@escaping () -> Void) -> Void' to specified type 'Int'}}
+}
+
+nonisolated func testUse(v1: TestFromProtocol, v2: TestFromType, v3: TestSubclass, v4: TestFromMethod, v5: TestFromMethod.Type) async {
+  var val: Int = 0
+
+  await v1.compute { val += 1 } // No execution warning because parameter type isn't Sendable
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+
+  await v1.compute { @Sendable in val += 1 } // expected-warning {{mutation of captured var 'val' in concurrently-executing code}}
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+
+  await v2.compute { val += 1 } // No execution warning because parameter type isn't Sendable
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+
+  await v2.compute { @Sendable in val += 1 } // expected-warning {{mutation of captured var 'val' in concurrently-executing code}}
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+
+  await v3.subCompute { val += 1 } // No execution warning because parameter type isn't Sendable
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+
+  await v3.subCompute { @Sendable in val += 1 } // expected-warning {{mutation of captured var 'val' in concurrently-executing code}}
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+
+  await v4.compute { val += 1 } // No execution warning because parameter type isn't Sendable
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+
+  await v4.compute { @Sendable in val += 1 } // expected-warning {{mutation of captured var 'val' in concurrently-executing code}}
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+
+  await v5.computeStatic { val += 1 } // No execution warning because parameter type isn't Sendable
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+
+  await v5.computeStatic { @Sendable in val += 1 } // expected-warning {{mutation of captured var 'val' in concurrently-executing code}}
+  // expected-warning@-1 {{consider using asynchronous alternative function}}
+}
diff --git a/test/Concurrency/global_actor_sendable_fn_type_inference.swift b/test/Concurrency/global_actor_sendable_fn_type_inference.swift
index 809f616263bbb..8be706d85a4f8 100644
--- a/test/Concurrency/global_actor_sendable_fn_type_inference.swift
+++ b/test/Concurrency/global_actor_sendable_fn_type_inference.swift
@@ -1,8 +1,7 @@
-// RUN: %target-typecheck-verify-swift -strict-concurrency=complete -target %target-swift-5.1-abi-triple -enable-upcoming-feature RegionBasedIsolation -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-typecheck-verify-swift -strict-concurrency=complete -target %target-swift-5.1-abi-triple -enable-upcoming-feature GlobalActorIsolatedTypesUsability
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 func inferSendableFunctionType() {
   let closure: @MainActor () -> Void = {}
diff --git a/test/Concurrency/global_actor_serialized.swift b/test/Concurrency/global_actor_serialized.swift
index 5c802f1dcdf96..c6add51ab329e 100644
--- a/test/Concurrency/global_actor_serialized.swift
+++ b/test/Concurrency/global_actor_serialized.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -swift-version 5 -emit-module-path %t/SerializedStruct.swiftmodule -module-name SerializedStruct %S/Inputs/SerializedStruct.swift
 
-// RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -disable-availability-checking -swift-version 6 -I %t
+// RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -disable-availability-checking -swift-version 6 -I %t
 
 // REQUIRES: concurrency
 
@@ -14,5 +14,5 @@ import SerializedStruct // expected-warning {{add '@preconcurrency' to treat 'Se
 // use it to force the right checks happen.
 func test() async -> Int {
   let x = MySerializedStruct()
-  return await x.counter // expected-error {{non-sendable type 'MySerializedStruct' cannot be sent into main actor-isolated context in call to property 'counter'}}
+  return await x.counter // expected-error {{non-Sendable type 'MySerializedStruct' cannot be sent into main actor-isolated context in call to property 'counter'}}
 }
diff --git a/test/Concurrency/global_variables.swift b/test/Concurrency/global_variables.swift
index 88990d1b792a3..89b1153067727 100644
--- a/test/Concurrency/global_variables.swift
+++ b/test/Concurrency/global_variables.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/GlobalVariables.swiftmodule -module-name GlobalVariables -parse-as-library -strict-concurrency=minimal -swift-version 5 %S/Inputs/GlobalVariables.swift
-// RUN: %target-swift-frontend -disable-availability-checking -parse-as-library -swift-version 6 -I %t -emit-sil -o /dev/null -verify %s
+// RUN: %target-swift-frontend -disable-availability-checking -parse-as-library -swift-version 6 -I %t -emit-sil -o /dev/null -verify -verify-ignore-unrelated %s
 
 // REQUIRES: concurrency
 
diff --git a/test/Concurrency/hop_to_executor_unreachable_code.swift b/test/Concurrency/hop_to_executor_unreachable_code.swift
index 44c6834451c62..581c19da9f900 100644
--- a/test/Concurrency/hop_to_executor_unreachable_code.swift
+++ b/test/Concurrency/hop_to_executor_unreachable_code.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -verify -o /dev/null %s
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -verify -o /dev/null %s -strict-concurrency=targeted
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -verify -o /dev/null %s -strict-concurrency=complete
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -emit-sil -verify -o /dev/null %s -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // Check that the inserted hop-to-executor instructions don't cause a false
 // "unreachable code" warning.
diff --git a/test/Concurrency/implied_sendable_conformance_objc.swift b/test/Concurrency/implied_sendable_conformance_objc.swift
new file mode 100644
index 0000000000000..5844a2b2ad23f
--- /dev/null
+++ b/test/Concurrency/implied_sendable_conformance_objc.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -o /dev/null -I %S/Inputs/custom-modules %s -verify -parse-as-library -swift-version 6
+
+// REQUIRES: objc_interop
+// REQUIRES: concurrency
+
+import Foundation
+
+extension CGRect: Sendable {}
+// expected-warning@-1 {{extension declares a conformance of imported type 'CGRect' to imported protocol 'Sendable'; this will not behave correctly if the owners of 'CoreGraphics' introduce this conformance in the future}}
+// expected-note@-2 {{add '@retroactive' to silence this warning}}
+// expected-error@-3 {{conformance to 'Sendable' must occur in the same source file as struct 'CGRect'; use '@unchecked Sendable' for retroactive conformance}}
+protocol P: Sendable {}
+
+extension CGPoint: P {}
+
diff --git a/test/Concurrency/implied_sendable_conformance_swift5.swift b/test/Concurrency/implied_sendable_conformance_swift5.swift
index a3030d037452b..c3a01008ea574 100644
--- a/test/Concurrency/implied_sendable_conformance_swift5.swift
+++ b/test/Concurrency/implied_sendable_conformance_swift5.swift
@@ -5,13 +5,13 @@ protocol P: Sendable {}
 protocol Q: Sendable {}
 
 struct One<T> {  // expected-note {{consider making generic parameter 'T' conform to the 'Sendable' protocol}}
-  var t: T  // expected-warning {{stored property 't' of 'Sendable'-conforming generic struct 'One' has non-sendable type 'T'; this is an error in the Swift 6 language mode}}
+  var t: T  // expected-warning {{stored property 't' of 'Sendable'-conforming generic struct 'One' has non-Sendable type 'T'; this is an error in the Swift 6 language mode}}
 }
 
 extension One: P where T: P {}
 
 struct Both<T> {  // expected-note {{consider making generic parameter 'T' conform to the 'Sendable' protocol}}
-  var t: T  // expected-warning {{stored property 't' of 'Sendable'-conforming generic struct 'Both' has non-sendable type 'T'; this is an error in the Swift 6 language mode}}
+  var t: T  // expected-warning {{stored property 't' of 'Sendable'-conforming generic struct 'Both' has non-Sendable type 'T'; this is an error in the Swift 6 language mode}}
 }
 
 extension Both: P where T: P {}
diff --git a/test/Concurrency/implied_sendable_conformance_swift6.swift b/test/Concurrency/implied_sendable_conformance_swift6.swift
index 53cde47a3452e..3b3c2ef5eea05 100644
--- a/test/Concurrency/implied_sendable_conformance_swift6.swift
+++ b/test/Concurrency/implied_sendable_conformance_swift6.swift
@@ -4,7 +4,7 @@ protocol P: Sendable {}
 protocol Q: Sendable {}
 
 struct One<T> {  // expected-note {{consider making generic parameter 'T' conform to the 'Sendable' protocol}}
-  var t: T  // expected-error {{stored property 't' of 'Sendable'-conforming generic struct 'One' has non-sendable type 'T'}}
+  var t: T  // expected-error {{stored property 't' of 'Sendable'-conforming generic struct 'One' has non-Sendable type 'T'}}
 }
 
 extension One: P where T: P {}
@@ -14,7 +14,7 @@ extension One: P where T: P {}
 // expected-note@-4 {{did you mean to explicitly state the conformance with different bounds?}}
 
 struct Both<T> { // expected-note {{consider making generic parameter 'T' conform to the 'Sendable' protocol}}
-  var t: T  // expected-error {{stored property 't' of 'Sendable'-conforming generic struct 'Both' has non-sendable type 'T'}}
+  var t: T  // expected-error {{stored property 't' of 'Sendable'-conforming generic struct 'Both' has non-Sendable type 'T'}}
 }
 
 extension Both: P where T: P {}
diff --git a/test/Concurrency/import_nsnotificationname_constants_as_nonisolated.swift b/test/Concurrency/import_nsnotificationname_constants_as_nonisolated.swift
index 4fea42e742826..7d04d8e9a8fc3 100644
--- a/test/Concurrency/import_nsnotificationname_constants_as_nonisolated.swift
+++ b/test/Concurrency/import_nsnotificationname_constants_as_nonisolated.swift
@@ -34,8 +34,7 @@ extern NSNotificationName const TestIsolatedTrigger __attribute__((swift_name("T
 func testAsync() async {
   print(Test.didTrigger) // Ok (property is nonisolated)
   print(Test.isolatedTrigger)
-  // expected-warning@-1 {{expression is 'async' but is not marked with 'await'; this is an error in the Swift 6 language mode}}
-  // expected-note@-2 {{property access is 'async'}}
+  // expected-warning@-1 {{main actor-isolated class property 'isolatedTrigger' cannot be accessed from outside of the actor}}
 }
 
 @MainActor
diff --git a/test/Concurrency/isolated_any.swift b/test/Concurrency/isolated_any.swift
index 8a19f92f0791e..ca4564e493208 100644
--- a/test/Concurrency/isolated_any.swift
+++ b/test/Concurrency/isolated_any.swift
@@ -64,11 +64,23 @@ func testEraseFromIsolatedArgument() {
   requireIsolatedAnyWithActorArgument(hasIsolatedArgument)
 }
 
-func requireSendableNonIsolated(_ fn: @Sendable () -> ()) {}
+func requireSendableNonIsolated(_ fn: @Sendable () async -> ()) {}
 func testConvertIsolatedAnyToNonIsolated(fn: @Sendable @isolated(any) () -> ()) {
   requireSendableNonIsolated(fn)
 }
 
+func requireSendableNonIsolated_sync(_ fn: @Sendable () -> ()) {}
+func testConvertIsolatedAnyToNonIsolated_sync(fn: @Sendable @isolated(any) () -> ()) {
+  // expected-warning @+1 {{converting @isolated(any) function of type '@isolated(any) @Sendable () -> ()' to synchronous function type '@Sendable () -> ()' is not allowed; this will be an error in a future Swift language mode}}
+  requireSendableNonIsolated_sync(fn)
+}
+
+func requireNonSendableNonIsolated_sync(_ fn: () -> ()) {}
+func testConvertIsolatedAnyToNonSendableNonIsolated_sync(fn: @isolated(any) () -> ()) {
+  // expected-warning @+1 {{converting @isolated(any) function of type '@isolated(any) () -> ()' to synchronous function type '() -> ()' is not allowed; this will be an error in a future Swift language mode}}
+  requireNonSendableNonIsolated_sync(fn)
+}
+
 func requireSendableGlobalActor(_ fn: @Sendable @MainActor () -> ()) {}
 func testConvertIsolatedAnyToMainActor(fn: @Sendable @isolated(any) () -> ()) {
   // expected-error @+1 {{cannot convert value of type '@isolated(any) @Sendable () -> ()' to expected argument type '@MainActor @Sendable () -> ()'}}
@@ -76,12 +88,12 @@ func testConvertIsolatedAnyToMainActor(fn: @Sendable @isolated(any) () -> ()) {
 }
 
 func extractFunctionIsolation(_ fn: @isolated(any) @Sendable @escaping () async -> Void) {
-  let _: (any Actor)? = extractIsolation(fn)
+  let _: (any Actor)? = extractIsolation(fn) // expected-warning{{'extractIsolation' is deprecated: Use `.isolation` on @isolated(any) closure values instead.}}
 
   let myActor = A()
-  let _: (any Actor)? = extractIsolation(myActor.asyncActorFunction)
-  let _: (any Actor)? = extractIsolation(myActor.asyncThrowsActorFunction)
-  let _: (any Actor)? = extractIsolation(myActor.actorFunctionWithArgs(value:))
+  let _: (any Actor)? = extractIsolation(myActor.asyncActorFunction) // expected-warning{{'extractIsolation' is deprecated: Use `.isolation` on @isolated(any) closure values instead.}}
+  let _: (any Actor)? = extractIsolation(myActor.asyncThrowsActorFunction) // expected-warning{{'extractIsolation' is deprecated: Use `.isolation` on @isolated(any) closure values instead.}}
+  let _: (any Actor)? = extractIsolation(myActor.actorFunctionWithArgs(value:)) // expected-warning{{'extractIsolation' is deprecated: Use `.isolation` on @isolated(any) closure values instead.}}
 }
 
 func extractFunctionIsolationExpr(
@@ -125,8 +137,22 @@ func testFunctionIsolationExprTuple(
   return (fn1?.isolation, fn2?.isolation)
 }
 
-func nonSendableIsolatedAny(
-  _ fn: @escaping @isolated(any) () -> Void // expected-note {{parameter 'fn' is implicitly non-sendable}}
+func nonSendableIsolatedAnySyncToSendableSync(
+  _ fn: @escaping @isolated(any) () -> Void // expected-note {{parameter 'fn' is implicitly non-Sendable}}
+) {
+  let _: @Sendable () -> Void = fn  // expected-warning {{using non-Sendable parameter 'fn' in a context expecting a '@Sendable' closure}}
+  // expected-warning @-1 {{converting @isolated(any) function of type '@isolated(any) () -> Void' to synchronous function type '@Sendable () -> Void' is not allowed; this will be an error in a future Swift language mode}}
+}
+
+func nonSendableIsolatedAnyAsyncToSendableSync(
+  _ fn: @escaping @isolated(any) () async -> Void // expected-note {{parameter 'fn' is implicitly non-Sendable}}
+) {
+  let _: @Sendable () -> Void = fn  // expected-warning {{using non-Sendable parameter 'fn' in a context expecting a '@Sendable' closure}}
+  // expected-error @-1 {{invalid conversion from 'async' function of type '@isolated(any) () async -> Void' to synchronous function type '@Sendable () -> Void'}}
+}
+
+func nonSendableIsolatedAnyAsyncToSendableAsync(
+  _ fn: @escaping @isolated(any) () async -> Void // expected-note {{parameter 'fn' is implicitly non-Sendable}}
 ) {
-  let _: @Sendable () -> Void = fn  // expected-warning {{using non-sendable parameter 'fn' in a context expecting a @Sendable closure}}
+  let _: @Sendable () async -> Void = fn  // expected-warning {{using non-Sendable parameter 'fn' in a context expecting a '@Sendable' closure}}
 }
diff --git a/test/Concurrency/isolated_captures.swift b/test/Concurrency/isolated_captures.swift
index 230d496750820..f334be3ad1cb5 100644
--- a/test/Concurrency/isolated_captures.swift
+++ b/test/Concurrency/isolated_captures.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -verify -target %target-swift-5.1-abi-triple -strict-concurrency=complete -verify-additional-prefix region-isolation- -emit-sil -o /dev/null %s
+// RUN: %target-swift-frontend -verify -target %target-swift-5.1-abi-triple -strict-concurrency=complete -emit-sil -o /dev/null %s
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
@@ -39,9 +39,9 @@ class NotSendable {
   MyActor.ns = ns
 
   await { @YourActor in
-    // expected-region-isolation-warning @+3 {{sending 'ns' risks causing data races}}
-    // expected-region-isolation-note @+2 {{global actor 'MyActor'-isolated 'ns' is captured by a global actor 'YourActor'-isolated closure. global actor 'YourActor'-isolated uses in closure may race against later global actor 'MyActor'-isolated uses}}
-    // expected-complete-warning@+1 {{capture of 'ns' with non-sendable type 'NotSendable' in an isolated closure; this is an error in the Swift 6 language mode}}
+    // expected-warning @+3 {{sending 'ns' risks causing data races}}
+    // expected-note @+2 {{global actor 'MyActor'-isolated 'ns' is captured by a global actor 'YourActor'-isolated closure. global actor 'YourActor'-isolated uses in closure may race against later global actor 'MyActor'-isolated uses}}
+    // expected-complete-warning@+1 {{capture of 'ns' with non-Sendable type 'NotSendable' in an isolated closure; this is an error in the Swift 6 language mode}}
     YourActor.ns = ns
   }()
 
@@ -61,9 +61,9 @@ class NotSendable {
   ns.stash()
 
   await { @YourActor in
-    // expected-region-isolation-warning @+3 {{sending 'ns' risks causing data races}}
-    // expected-region-isolation-note @+2 {{global actor 'MyActor'-isolated 'ns' is captured by a global actor 'YourActor'-isolated closure. global actor 'YourActor'-isolated uses in closure may race against later global actor 'MyActor'-isolated uses}}
-    // expected-complete-warning@+1 {{capture of 'ns' with non-sendable type 'NotSendable' in an isolated closure; this is an error in the Swift 6 language mode}}
+    // expected-warning @+3 {{sending 'ns' risks causing data races}}
+    // expected-note @+2 {{global actor 'MyActor'-isolated 'ns' is captured by a global actor 'YourActor'-isolated closure. global actor 'YourActor'-isolated uses in closure may race against later global actor 'MyActor'-isolated uses}}
+    // expected-complete-warning@+1 {{capture of 'ns' with non-Sendable type 'NotSendable' in an isolated closure; this is an error in the Swift 6 language mode}}
     YourActor.ns = ns
   }()
 
@@ -82,9 +82,9 @@ class NotSendable {
   let ns = NotSendable()
 
   await { @YourActor in
-    // expected-region-isolation-warning @+3 {{sending 'ns' risks causing data races}}
-    // expected-region-isolation-note @+2 {{global actor 'MyActor'-isolated 'ns' is captured by a global actor 'YourActor'-isolated closure. global actor 'YourActor'-isolated uses in closure may race against later global actor 'MyActor'-isolated uses}}
-    // expected-complete-warning@+1 {{capture of 'ns' with non-sendable type 'NotSendable' in an isolated closure; this is an error in the Swift 6 language mode}}
+    // expected-warning @+3 {{sending 'ns' risks causing data races}}
+    // expected-note @+2 {{global actor 'MyActor'-isolated 'ns' is captured by a global actor 'YourActor'-isolated closure. global actor 'YourActor'-isolated uses in closure may race against later global actor 'MyActor'-isolated uses}}
+    // expected-complete-warning@+1 {{capture of 'ns' with non-Sendable type 'NotSendable' in an isolated closure; this is an error in the Swift 6 language mode}}
     YourActor.ns = ns
   }()
 
diff --git a/test/Concurrency/isolated_conformance.swift b/test/Concurrency/isolated_conformance.swift
index 03c702f2a1734..8f71f601b24be 100644
--- a/test/Concurrency/isolated_conformance.swift
+++ b/test/Concurrency/isolated_conformance.swift
@@ -1,6 +1,5 @@
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 6 -enable-experimental-feature IsolatedConformances %s
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete %s
 
-// REQUIRES: swift_feature_IsolatedConformances
 // REQUIRES: concurrency
 
 protocol P {
@@ -11,15 +10,64 @@ protocol P {
 // Definition of isolated conformances
 // ----------------------------------------------------------------------------
 
-// expected-error@+4{{conformance of 'CWithNonIsolated' to protocol 'P' crosses into main actor-isolated code and can cause data races}}
+// expected-warning@+4{{conformance of 'CWithNonIsolated' to protocol 'P' crosses into main actor-isolated code and can cause data races}}
 // expected-note@+3{{mark all declarations used in the conformance 'nonisolated'}}
 // expected-note@+2{{isolate this conformance to the main actor with '@MainActor'}}{{25-25=@MainActor }}
 @MainActor
 class CWithNonIsolated: P {
-  // expected-note@-1{{turn data races into runtime errors with '@preconcurrency'}}
+  // expected-note@-1{{turn data races into runtime errors with '@preconcurrency'}}{{25-25=@preconcurrency }}
   func f() { } // expected-note{{main actor-isolated instance method 'f()' cannot satisfy nonisolated requirement}}
 }
 
+// Make sure we correctly apply the conformance attribute for more complex
+// inheritance entries.
+do {
+  protocol EmptyP {}
+  struct Nested {
+    protocol P { func f() }
+    protocol Q { func f() }
+  }
+  do {
+    // expected-warning@+4 {{conformance of 'S' to protocol 'P' crosses into main actor-isolated code and can cause data races}}
+    // expected-note@+3 {{mark all declarations used in the conformance 'nonisolated'}}
+    // expected-note@+2 {{isolate this conformance to the main actor with '@MainActor'}}{{26-26=@MainActor }}
+    // expected-note@+1 {{turn data races into runtime errors with '@preconcurrency'}}{{26-26=@preconcurrency }}
+    @MainActor struct S: Nested.P {
+      func f() {} // expected-note {{main actor-isolated instance method 'f()' cannot satisfy nonisolated requirement}}
+    }
+  }
+  do {
+    // Attribute inserted *before* '@unsafe'.
+    @MainActor struct S: @unsafe Nested.P {
+    // expected-warning@-1 {{conformance of 'S' to protocol 'P' crosses into main actor-isolated code and can cause data races}}
+    // expected-note@-2 {{mark all declarations used in the conformance 'nonisolated'}}
+    // expected-note@-3 {{isolate this conformance to the main actor with '@MainActor'}}{{26-26=@MainActor }}
+    // expected-note@-4 {{turn data races into runtime errors with '@preconcurrency'}}{{26-26=@preconcurrency }}
+      func f() {} // expected-note {{main actor-isolated instance method 'f()' cannot satisfy nonisolated requirement}}
+    }
+  }
+  do {
+    // expected-warning@+5 {{conformance of 'S' to protocol 'Q' crosses into main actor-isolated code and can cause data races}}
+    // expected-warning@+4 {{conformance of 'S' to protocol 'P' crosses into main actor-isolated code and can cause data races}}
+    // expected-note@+3 2 {{mark all declarations used in the conformance 'nonisolated'}}
+    // expected-note@+2 2 {{isolate this conformance to the main actor with '@MainActor'}}{{26-26=@MainActor }}
+    // expected-note@+1 2 {{turn data races into runtime errors with '@preconcurrency'}}{{26-26=@preconcurrency }}
+    @MainActor struct S: Nested.P & Nested.Q {
+      func f() {} // expected-note 2 {{main actor-isolated instance method 'f()' cannot satisfy nonisolated requirement}}
+    }
+  }
+  do {
+    // FIXME: We shouldn't be applying nonisolated to both protocols.
+    // expected-warning@+4 {{conformance of 'S' to protocol 'P' crosses into main actor-isolated code and can cause data races}}
+    // expected-note@+3 {{mark all declarations used in the conformance 'nonisolated'}}
+    // expected-note@+2 {{isolate this conformance to the main actor with '@MainActor'}}{{26-26=@MainActor }}
+    // expected-note@+1 {{turn data races into runtime errors with '@preconcurrency'}}{{26-26=@preconcurrency }}
+    @MainActor struct S: Nested.P & EmptyP  {
+      func f() {} // expected-note {{main actor-isolated instance method 'f()' cannot satisfy nonisolated requirement}}
+    }
+  }
+}
+
 actor SomeActor { }
 
 // Isolated conformances need a global-actor-constrained type.
@@ -54,7 +102,7 @@ protocol Q {
   associatedtype A: P
 }
 
-// expected-error@+2{{conformance of 'SMissingIsolation' to protocol 'Q' crosses into main actor-isolated code and can cause data races}}
+// expected-warning@+2{{conformance of 'SMissingIsolation' to protocol 'Q' crosses into main actor-isolated code and can cause data races}}
 @MainActor
 struct SMissingIsolation: Q {
   // expected-note@-1{{conformance depends on main actor-isolated conformance of 'C' to protocol 'P'}}
@@ -66,7 +114,7 @@ struct PWrapper<T: P>: P {
   func f() { }
 }
 
-// expected-error@+2{{conformance of 'SMissingIsolationViaWrapper' to protocol 'Q' crosses into main actor-isolated code and can cause data races}}
+// expected-warning@+2{{conformance of 'SMissingIsolationViaWrapper' to protocol 'Q' crosses into main actor-isolated code and can cause data races}}
 @MainActor
 struct SMissingIsolationViaWrapper: Q {
   // expected-note@-1{{conformance depends on main actor-isolated conformance of 'C' to protocol 'P'}}
@@ -84,7 +132,7 @@ struct S: @MainActor Q {
   typealias A = C
 }
 
-// expected-error@+3{{conformance of 'SMismatchedActors' to protocol 'Q' crosses into global actor 'SomeGlobalActor'-isolated code and can cause data races}}
+// expected-warning@+3{{conformance of 'SMismatchedActors' to protocol 'Q' crosses into global actor 'SomeGlobalActor'-isolated code and can cause data races}}
 // expected-note@+2{{conformance depends on global actor 'SomeGlobalActor'-isolated conformance of 'C2' to protocol 'P'}}
 @MainActor
 struct SMismatchedActors: @MainActor Q {
@@ -99,6 +147,15 @@ struct PSendableS: @MainActor PSendable { // expected-note{{requirement specifie
   func f() { }
 }
 
+protocol R: SendableMetatype {
+  func f()
+}
+
+// expected-error@+1{{cannot form main actor-isolated conformance of 'RSendableSMainActor' to SendableMetatype-inheriting protocol 'R'}}
+@MainActor struct RSendableSMainActor: @MainActor R {
+  func f() { }
+}
+
 // ----------------------------------------------------------------------------
 // Use checking of isolated conformances.
 // ----------------------------------------------------------------------------
@@ -149,7 +206,50 @@ func testIsolatedConformancesOfOtherGlobalActor(c: CMismatchedIsolation) {
 }
 
 func testIsolationConformancesFromOutside(c: C) {
-  acceptP(c) // expected-error{{main actor-isolated conformance of 'C' to 'P' cannot be used in nonisolated context}}
-  let _: any P = c // expected-error{{main actor-isolated conformance of 'C' to 'P' cannot be used in nonisolated context}}
-  let _ = PWrapper<C>() // expected-error{{main actor-isolated conformance of 'C' to 'P' cannot be used in nonisolated context}}
+  acceptP(c) // expected-warning{{main actor-isolated conformance of 'C' to 'P' cannot be used in nonisolated context}}
+  let _: any P = c // expected-warning{{main actor-isolated conformance of 'C' to 'P' cannot be used in nonisolated context}}
+  let _ = PWrapper<C>() // expected-warning{{main actor-isolated conformance of 'C' to 'P' cannot be used in nonisolated context}}
+}
+
+protocol HasAssociatedType {
+  associatedtype A
+}
+
+func acceptHasAssocWithP<T: HasAssociatedType>(_: T) where T.A: P { }
+
+func acceptSendableHasAssocWithP<T: Sendable & HasAssociatedType>(_: T) where T.A: P { }
+// expected-note@-1{{'acceptSendableHasAssocWithP' declared here}}
+
+
+struct HoldsC: HasAssociatedType {
+  typealias A = C
+}
+
+extension HasAssociatedType {
+  static func acceptAliased<T: P>(_: T.Type) where A == T { }
+}
+
+extension HasAssociatedType where Self: Sendable {
+  static func acceptSendableAliased<T: P>(_: T.Type) where A == T { }
+}
+
+func testIsolatedConformancesOnAssociatedTypes(hc: HoldsC, c: C) {
+  acceptHasAssocWithP(hc)
+  acceptSendableHasAssocWithP(hc) // expected-error{{main actor-isolated conformance of 'C' to 'P' cannot satisfy conformance requirement for a 'Sendable' type parameter }}
+
+  HoldsC.acceptAliased(C.self) // okay
+
+  // FIXME: the following should produce an error, because the isolated
+  // conformance of C: P can cross isolation boundaries via the Sendable Self's
+  // associated type.
+  HoldsC.acceptSendableAliased(C.self)
+}
+
+
+struct MyHashable: @MainActor Hashable {
+  var counter = 0
+}
+
+@concurrent func testMyHashableSet() async {
+  let _: Set<MyHashable> = [] // expected-warning{{main actor-isolated conformance of 'MyHashable' to 'Hashable' cannot be used in nonisolated context}}
 }
diff --git a/test/Concurrency/isolated_conformance_6.swift b/test/Concurrency/isolated_conformance_6.swift
new file mode 100644
index 0000000000000..c77dad3f1520b
--- /dev/null
+++ b/test/Concurrency/isolated_conformance_6.swift
@@ -0,0 +1,22 @@
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 6 %s
+
+// REQUIRES: concurrency
+
+protocol P: SendableMetatype {
+  func f()
+}
+
+@preconcurrency
+protocol Q: SendableMetatype {
+  func f()
+}
+
+// expected-error@+1{{cannot form main actor-isolated conformance of 'PSendableSMainActor' to SendableMetatype-inheriting protocol 'P'}}
+@MainActor struct PSendableSMainActor: @MainActor P {
+  func f() { }
+}
+
+// expected-warning@+1{{cannot form main actor-isolated conformance of 'QSendableSMainActor' to SendableMetatype-inheriting protocol 'Q'}}
+@MainActor struct QSendableSMainActor: @MainActor Q {
+  func f() { }
+}
diff --git a/test/Concurrency/isolated_conformance_default_actor.swift b/test/Concurrency/isolated_conformance_default_actor.swift
index 3b30223420731..5626fdff00ea4 100644
--- a/test/Concurrency/isolated_conformance_default_actor.swift
+++ b/test/Concurrency/isolated_conformance_default_actor.swift
@@ -1,8 +1,9 @@
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 6 -enable-experimental-feature IsolatedConformances -default-isolation MainActor %s
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 6 -default-isolation MainActor %s
 
-// REQUIRES: swift_feature_IsolatedConformances
 // REQUIRES: concurrency
 
+@MainActor func onMain() { }
+
 nonisolated
 protocol P {
   func f()
@@ -13,8 +14,14 @@ protocol Q {
   func g()
 }
 
+// expected-note@+4{{turn data races into runtime errors with '@preconcurrency'}}
+// expected-note@+3{{isolate this conformance to the main actor with '@MainActor'}}
+// expected-note@+2{{mark all declarations used in the conformance 'nonisolated'}}
+// expected-error@+1{{conformance of 'CImplicitMainActorNonisolatedConformance' to protocol 'P' crosses into main actor-isolated code and can cause data races}}
 class CImplicitMainActorNonisolatedConformance: nonisolated P {
-  func f() { } // error: explicitly nonisolated conformance
+  func f() { // expected-note{{main actor-isolated instance method 'f()' cannot satisfy nonisolated requirement}}
+    onMain() // okay, f is on @MainActor
+  }
 }
 
 
@@ -43,17 +50,51 @@ nonisolated class CNonIsolated: P {
   @MainActor func f() { } // expected-note{{main actor-isolated instance method 'f()' cannot satisfy nonisolated requirement}}
 }
 
+// Synthesized conformances
+struct EquatableStruct: Equatable {
+  var state: Int = 0
+}
+
+struct HashableStruct: Hashable {
+  var state: Int = 0
+}
+
+enum RawRepresentableEnum: Int {
+case one
+case two
+}
+
+class CodableClass: Codable {
+  var state: Int = 0
+}
+
+class OtherClass {
+  var otherState: any Encodable.Type = CodableClass.self
+}
+
+struct Landmark: Codable {
+  var name: String
+  var foundingYear: Int
+}
+
 func acceptSendablePMeta<T: Sendable & P>(_: T.Type) { }
 func acceptSendableQMeta<T: Sendable & Q>(_: T.Type) { }
 
 nonisolated func testConformancesFromNonisolated() {
-  let _: any P = CExplicitMainActor() // expected-error{{main actor-isolated conformance of 'CExplicitMainActor' to 'P' cannot be used in nonisolated context}}
-  let _: any P = CImplicitMainActor() // expected-error{{main actor-isolated conformance of 'CImplicitMainActor' to 'P' cannot be used in nonisolated context}}
-
   let _: any P = CNonIsolated()
   let _: any P = CImplicitMainActorNonisolatedConformance()
 
   // Okay, these are nonisolated conformances.
   let _: any Q = CExplicitMainActor()
   let _: any Q = CImplicitMainActor()
+
+  // Error, these are main-actor-isolated conformances
+  let _: any P = CExplicitMainActor() // expected-error{{main actor-isolated conformance of 'CExplicitMainActor' to 'P' cannot be used in nonisolated context}}
+  let _: any P = CImplicitMainActor() // expected-error{{main actor-isolated conformance of 'CImplicitMainActor' to 'P' cannot be used in nonisolated context}}
+
+
+  let _: any Equatable.Type = EquatableStruct.self // expected-error{{main actor-isolated conformance of 'EquatableStruct' to 'Equatable' cannot be used in nonisolated context}}
+  let _: any Hashable.Type = HashableStruct.self // expected-error{{main actor-isolated conformance of 'HashableStruct' to 'Hashable' cannot be used in nonisolated context}}
+  let _: any RawRepresentable.Type = RawRepresentableEnum.self
+  let _: any Encodable.Type = CodableClass.self // expected-error{{main actor-isolated conformance of 'CodableClass' to 'Encodable' cannot be used in nonisolated context}}
 }
diff --git a/test/Concurrency/isolated_conformance_inference.swift b/test/Concurrency/isolated_conformance_inference.swift
index ed0bc91ac2a1d..35bf78603a3ba 100644
--- a/test/Concurrency/isolated_conformance_inference.swift
+++ b/test/Concurrency/isolated_conformance_inference.swift
@@ -1,8 +1,7 @@
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 6 -enable-experimental-feature IsolatedConformances -enable-experimental-feature InferIsolatedConformances %s
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 6 -enable-upcoming-feature InferIsolatedConformances %s
 
-// REQUIRES: swift_feature_IsolatedConformances
-// REQUIRES: swift_feature_InferIsolatedConformances
 // REQUIRES: concurrency
+// REQUIRES: swift_feature_InferIsolatedConformances
 
 protocol P {
   func f()
@@ -33,6 +32,11 @@ extension CExplicit: Q {
   func g() { }
 }
 
+@SomeGlobalActor
+class CViaNonisolatedWitness: P {
+  nonisolated func f() { } // okay! conformance above is nonisolated via this witness
+}
+
 // expected-error@+3{{conformance of 'CNonIsolated' to protocol 'P' crosses into global actor 'SomeGlobalActor'-isolated code and can cause data races}}
 // expected-note@+2{{turn data races into runtime errors with '@preconcurrency'}}
 // expected-note@+1{{isolate this conformance to the global actor 'SomeGlobalActor' with '@SomeGlobalActor'}}{{33-33=@SomeGlobalActor }}
@@ -43,11 +47,52 @@ nonisolated class CNonIsolated: P {
 func acceptSendablePMeta<T: Sendable & P>(_: T.Type) { }
 func acceptSendableQMeta<T: Sendable & Q>(_: T.Type) { }
 
-nonisolated func testConformancesFromNonisolated() {
+// @preconcurrency suppresses actor isolation inference
+struct NotSendable: Equatable, Hashable {
+}
+
+@available(*, unavailable)
+extension NotSendable: Sendable {}
+
+extension NotSendable : Codable {}
+
+@MainActor
+struct TestDerivedCodable : @preconcurrency Codable {
+  var x: NotSendable
+}
+
+nonisolated func testConformancesFromNonisolated(tdc: TestDerivedCodable) {
   let _: any P = CExplicit() // expected-error{{global actor 'SomeGlobalActor'-isolated conformance of 'CExplicit' to 'P' cannot be used in nonisolated context}}
 
   let _: any P = CNonIsolated()
 
   // Okay, these are nonisolated conformances.
   let _: any Q = CExplicit()
+
+  let _: any P = CViaNonisolatedWitness()
+
+  let _: any Codable = tdc
+}
+
+protocol P2 {
+  func g()
+}
+
+struct DifferingConformances: @MainActor P {
+  @MainActor func f() { }
 }
+
+extension DifferingConformances: @SomeGlobalActor P2 {
+  @SomeGlobalActor func g() { }
+}
+
+@MainActor
+class InferMeDefaults {
+  var mainState: any P.Type = DifferingConformances.self
+  var someGlobalActorState: any P2.Type = DifferingConformances.self // expected-error{{global actor 'SomeGlobalActor'-isolated default value in a main actor-isolated context}}
+  var bothState: any (P & P2).Type = DifferingConformances.self // expected-error{{default argument cannot be both main actor-isolated and global actor 'SomeGlobalActor'-isolated}}
+}
+
+protocol PDerived: P {}
+
+@MainActor struct ImpliedConformanceInference: PDerived { func f() {} }
diff --git a/test/Concurrency/isolated_conformance_inference_with_default_actor.swift b/test/Concurrency/isolated_conformance_inference_with_default_actor.swift
new file mode 100644
index 0000000000000..57a86a58978b7
--- /dev/null
+++ b/test/Concurrency/isolated_conformance_inference_with_default_actor.swift
@@ -0,0 +1,9 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/isolated_conformance_other.swiftmodule %S/Inputs/isolated_conformance_other.swift -swift-version 6
+// RUN: %target-typecheck-verify-swift -I %t -swift-version 6 -enable-upcoming-feature InferIsolatedConformances -default-isolation MainActor -swift-version 6
+// REQUIRES: swift_feature_InferIsolatedConformances
+
+import isolated_conformance_other
+
+struct S1: P { func f() {} }
+struct S2: PDerived { func f() {} }
diff --git a/test/Concurrency/isolated_conformance_migrate.swift b/test/Concurrency/isolated_conformance_migrate.swift
new file mode 100644
index 0000000000000..7a1850ba14e6c
--- /dev/null
+++ b/test/Concurrency/isolated_conformance_migrate.swift
@@ -0,0 +1,61 @@
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 6 -enable-upcoming-feature InferIsolatedConformances:migrate %s
+
+// REQUIRES: concurrency
+// REQUIRES: swift_feature_InferIsolatedConformances
+
+protocol P { }
+protocol Q: P { }
+
+struct S: P { }
+
+struct S2: Q { }
+
+@MainActor
+struct MA1: P { }
+// expected-warning@-1{{conformance of 'MA1' to 'P' should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'}}{{13-13=nonisolated }}
+
+@MainActor
+struct MA2: Q { }
+// expected-warning@-1{{conformance of 'MA2' to 'Q' should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'}}{{13-13=nonisolated }}
+
+@MainActor
+struct MA3 { }
+
+extension MA3: P, Q { }
+// expected-warning@-1{{conformance of 'MA3' to 'P' should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'}}{{16-16=nonisolated }}
+// expected-warning@-2{{conformance of 'MA3' to 'Q' should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'}}{{19-19=nonisolated }}
+
+@MainActor
+struct MA4: @MainActor P { }
+
+@MainActor
+struct MA5: nonisolated P { }
+
+// Make sure we correctly apply the conformance attribute for more complex
+// inheritance entries.
+do {
+  @MainActor protocol MainActorP { }
+  enum Nested {
+    protocol P { }
+    protocol Q { }
+  }
+  do {
+    @MainActor struct S: Nested.P { }
+    // expected-warning@-1 {{conformance of 'S' to 'P' should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'}}{{26-26=nonisolated }}
+  }
+  do {
+    // Modifier inserted *after* '@unsafe'.
+    @MainActor struct S: @unsafe Nested.P { }
+    // expected-warning@-1 {{conformance of 'S' to 'P' should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'}}{{34-34=nonisolated }}
+  }
+  do {
+    @MainActor struct S: Nested.P & Nested.Q { }
+    // expected-warning@-1 {{conformance of 'S' to 'P' should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'}}{{26-26=nonisolated }}
+    // expected-warning@-2 {{conformance of 'S' to 'Q' should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'}}{{26-26=nonisolated }}
+  }
+  do {
+    // FIXME: We shouldn't be applying nonisolated to both protocols.
+    @MainActor struct S: Nested.P & MainActorP { }
+    // expected-warning@-1 {{conformance of 'S' to 'P' should be marked 'nonisolated' to retain its behavior with upcoming feature 'InferIsolatedConformances'}}{{26-26=nonisolated }}
+  }
+}
diff --git a/test/Concurrency/isolated_default_arguments.swift b/test/Concurrency/isolated_default_arguments.swift
index a5c07d7beb4d9..e22eabc55e095 100644
--- a/test/Concurrency/isolated_default_arguments.swift
+++ b/test/Concurrency/isolated_default_arguments.swift
@@ -59,12 +59,10 @@ func nonisolatedCaller() {
 }
 
 func nonisolatedAsyncCaller() async {
-  // expected-error@+2 {{expression is 'async' but is not marked with 'await'}}
-  // expected-note@+1 {{calls to global function 'mainActorDefaultArg(value:)' from outside of its actor context are implicitly asynchronous}}
+  // expected-error@+1 {{main actor-isolated global function 'mainActorDefaultArg(value:)' cannot be called from outside of the actor}} {{3-3=await }}
   mainActorDefaultArg()
 
-  // expected-error@+2 {{expression is 'async' but is not marked with 'await'}}
-  // expected-note@+1 {{calls to global function 'mainActorClosure(closure:)' from outside of its actor context are implicitly asynchronous}}
+  // expected-error@+1 {{main actor-isolated global function 'mainActorClosure(closure:)' cannot be called from outside of the actor}} {{3-3=await }}
   mainActorClosure()
 
   await mainActorDefaultArg(value: requiresMainActor())
@@ -216,8 +214,7 @@ class C3 {
 
 class C4 {
   let task1 = Task {
-    // expected-error@+2 {{expression is 'async' but is not marked with 'await'}}
-    // expected-note@+1 {{calls to global function 'requiresMainActor()' from outside of its actor context are implicitly asynchronous}}
+    // expected-error@+1 {{main actor-isolated global function 'requiresMainActor()' cannot be called from outside of the actor}} {{5-5=await }}
     requiresMainActor()
   }
 
@@ -265,8 +262,7 @@ struct UseRequiresMain {
 }
 
 nonisolated func test() async {
-  // expected-warning@+2 {{expression is 'async' but is not marked with 'await'; this is an error in the Swift 6 language mode}}
-  // expected-note@+1 {{calls to initializer 'init()' from outside of its actor context are implicitly asynchronous}}
+  // expected-warning@+1 {{main actor-isolated initializer 'init()' cannot be called from outside of the actor; this is an error in the Swift 6 language mode}} {{7-7=await }}
   _ = UseRequiresMain()
 }
 
diff --git a/test/Concurrency/isolated_default_arguments_serialized.swift b/test/Concurrency/isolated_default_arguments_serialized.swift
index bc66aff5d77ba..3aae2f45834ca 100644
--- a/test/Concurrency/isolated_default_arguments_serialized.swift
+++ b/test/Concurrency/isolated_default_arguments_serialized.swift
@@ -2,12 +2,10 @@
 // RUN: %target-swift-frontend -emit-module -swift-version 5 -emit-module-path %t/SerializedDefaultArguments.swiftmodule -module-name SerializedDefaultArguments -enable-upcoming-feature IsolatedDefaultValues %S/Inputs/serialized_default_arguments.swift
 
 // RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -disable-availability-checking -swift-version 6 -I %t
-// RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -disable-availability-checking -swift-version 5 -I %t -enable-upcoming-feature RegionBasedIsolation -enable-upcoming-feature IsolatedDefaultValues -enable-upcoming-feature StrictConcurrency
+// RUN: %target-swift-frontend %s -emit-sil -o /dev/null -verify -disable-availability-checking -swift-version 5 -I %t -enable-upcoming-feature IsolatedDefaultValues -strict-concurrency=complete
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_IsolatedDefaultValues
-// REQUIRES: swift_feature_RegionBasedIsolation
-// REQUIRES: swift_feature_StrictConcurrency
 
 import SerializedDefaultArguments
 
diff --git a/test/Concurrency/isolated_default_property_inits.swift b/test/Concurrency/isolated_default_property_inits.swift
index 63e1c251ba665..19d19ec2a1d66 100644
--- a/test/Concurrency/isolated_default_property_inits.swift
+++ b/test/Concurrency/isolated_default_property_inits.swift
@@ -3,11 +3,10 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/OtherActors.swiftmodule -module-name OtherActors %S/Inputs/OtherActors.swift -target %target-swift-5.1-abi-triple
 
 // RUN: %target-swift-frontend -I %t  -target %target-swift-5.1-abi-triple -strict-concurrency=complete -enable-upcoming-feature IsolatedDefaultValues -parse-as-library -emit-sil -o /dev/null -verify %s
-// RUN: %target-swift-frontend -I %t  -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library -emit-sil -o /dev/null -verify -enable-upcoming-feature IsolatedDefaultValues -enable-upcoming-feature RegionBasedIsolation %s
+// RUN: %target-swift-frontend -I %t  -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library -emit-sil -o /dev/null -verify -enable-upcoming-feature IsolatedDefaultValues %s
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_IsolatedDefaultValues
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // This tests errors emitted in definite initialization; this test file cannot
 // have any type checker errors. Type checker errors for IsolatedDefaultValues
diff --git a/test/Concurrency/isolated_parameters.swift b/test/Concurrency/isolated_parameters.swift
index 0a6ba477a8da1..531c91e69944d 100644
--- a/test/Concurrency/isolated_parameters.swift
+++ b/test/Concurrency/isolated_parameters.swift
@@ -1,6 +1,4 @@
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -DALLOW_TYPECHECKER_ERRORS -verify-additional-prefix typechecker-
-
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -verify-additional-prefix tns-
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete %s -emit-sil -o /dev/null -verify
 
 // REQUIRES: asserts
 // REQUIRES: concurrency
@@ -8,7 +6,7 @@
 
 @available(SwiftStdlib 5.1, *)
 actor A {
-  func f() { } // expected-typechecker-note 5{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+  func f() { }
 }
 
 @available(SwiftStdlib 5.1, *)
@@ -16,22 +14,7 @@ extension Actor {
   func g() { }
 }
 
-@MainActor func mainActorFn() {} // expected-typechecker-note {{calls to global function 'mainActorFn()' from outside of its actor context are implicitly asynchronous}}
-
-#if ALLOW_TYPECHECKER_ERRORS
-
-@available(SwiftStdlib 5.1, *)
-func testA<T: Actor>(
-  a: isolated A,  // expected-typechecker-note {{previous 'isolated' parameter 'a'}}
-  b: isolated T,  // expected-typechecker-warning {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-  c: isolated Int // expected-typechecker-error {{'isolated' parameter type 'Int' does not conform to 'Actor' or 'DistributedActor'}}
-) {
-  a.f()
-  a.g()
-  b.g()
-}
-
-#endif
+@MainActor func mainActorFn() {}
 
 actor Other {
   func inc() {}
@@ -42,99 +25,31 @@ actor Counter {
   func pass(_ f: @Sendable  (Self) async -> Void) {}
 }
 
-#if ALLOW_TYPECHECKER_ERRORS
-
-// This is illegal at the SIL level so even though we could ignore this
-// note/warning, we will get a crash otherwise.
-@available(SwiftStdlib 5.1, *)
-// expected-typechecker-note@+2 {{previous 'isolated' parameter 'a'}}
-// expected-typechecker-warning@+1 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-func testDoubleIsolatedParams(a: isolated Counter, b: isolated Other) async {
-  a.inc()
-  b.inc()
-}
-
-func taaaa() async {
-  await Counter().pass { isoC in
-    await Other().pass { isoO in
-      await testDoubleIsolatedParams(a: isoC, b: isoO)
-    }
-  }
-}
-
-#endif
-
 @available(SwiftStdlib 5.1, *)
 typealias Fn = (isolated A) -> Void
 
 @available(SwiftStdlib 5.1, *)
 func globalFunc(_ a: A) { }
 
-#if ALLOW_TYPECHECKER_ERRORS
-
-@available(SwiftStdlib 5.1, *)
-func globalFuncIsolated(_: isolated A) { // expected-typechecker-note{{calls to global function 'globalFuncIsolated' from outside of its actor context are implicitly asynchronous}}
-  let _: Int = globalFuncIsolated // expected-typechecker-error{{cannot convert value of type '(isolated A) -> ()' to specified type 'Int'}}
-  let _: (A) -> Void = globalFuncIsolated // expected-typechecker-error{{cannot convert value of type '(isolated A) -> ()' to specified type '(A) -> Void'}}
-  let _: Fn = globalFunc // okay
-}
-
-@available(SwiftStdlib 5.1, *)
-// expected-typechecker-warning@+1 {{global function with 'isolated' parameter cannot have a global actor; this is an error in the Swift 6 language mode}}{{1-12=}}
-@MainActor func testIsolatedParamCalls(a: isolated A, b: A) {
-  globalFunc(a)
-  globalFunc(b)
-
-  globalFuncIsolated(a)
-  globalFuncIsolated(b) // expected-typechecker-error{{call to actor-isolated global function 'globalFuncIsolated' in a synchronous actor-isolated context}}
-}
-
-#endif
-
 @available(SwiftStdlib 5.1, *)
 func testIsolatedParamCallsAsync(a: isolated A, b: A) async {
   globalFunc(a)
   globalFunc(b)
 
-  #if ALLOW_TYPECHECKER_ERRORS
-  globalFuncIsolated(a)
-  globalFuncIsolated(b) // expected-typechecker-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-typechecker-note@-1{{calls to global function 'globalFuncIsolated' from outside of its actor context are implicitly asynchronous}}
-  await globalFuncIsolated(b)
-  #endif
 }
 
 @available(SwiftStdlib 5.1, *)
 func testIsolatedParamCaptures(a: isolated A) async {
-#if ALLOW_TYPECHECKER_ERRORS
-  let _ = { @MainActor in
-    a.f() // expected-typechecker-error {{call to actor-isolated instance method 'f()' in a synchronous main actor-isolated context}}
-  }
-
-  let _: @MainActor () -> () = {
-    a.f() // expected-typechecker-error {{call to actor-isolated instance method 'f()' in a synchronous main actor-isolated context}}
-  }
-#endif
-
   let _ = {
     a.f()
   }
-
-#if ALLOW_TYPECHECKER_ERRORS
-  let _ = { @Sendable in
-    a.f() // expected-typechecker-error {{call to actor-isolated instance method 'f()' in a synchronous nonisolated context}}
-  }
-#endif
 }
 
 actor MyActor {
-  func hello() {} // expected-typechecker-note {{calls to instance method 'hello()' from outside of its actor context are implicitly asynchronous}}
+  func hello() {}
 }
 
 // Compiler >= 5.3 is ended to suppress the parser error
-#if compiler(>=5.3) && ALLOW_TYPECHECKER_ERRORS
-typealias MyFn = (isolated: Int) -> Void // expected-typechecker-error {{function types cannot have argument labels; use '_' before 'isolated'}}
-#endif
 typealias MyFnFixed = (_: isolated MyActor) -> Void
 
 func standalone(_: isolated MyActor) {}
@@ -166,53 +81,23 @@ struct S: P {
   func j(isolated: Int) -> Int { return isolated }
   func k(isolated y: Int) -> Int { return j(isolated: y) }
   func l(isolated _: Int) -> Int { return k(isolated: 0) }
-  #if ALLOW_TYPECHECKER_ERRORS
-  func m(thing: MyActor) { thing.hello() } // expected-typechecker-error {{call to actor-isolated instance method 'hello()' in a synchronous nonisolated context}}
-  #else
   func m(thing: MyActor) { }
-  #endif
 }
 
 func checkConformer(_ s: S, _ p: any P, _ ma: MyActor) async {
   s.m(thing: ma)
   await p.m(thing: ma)
-  // expected-complete-warning@-1 {{passing argument of non-sendable type 'any P' into actor-isolated context may introduce data races}}
-  // expected-tns-warning @-2 {{sending 'p' risks causing data races}}
-  // expected-tns-note @-3 {{sending task-isolated 'p' to actor-isolated instance method 'm(thing:)' risks causing data races between actor-isolated and task-isolated uses}}
+  // expected-warning @-1 {{sending 'p' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'p' to actor-isolated instance method 'm(thing:)' risks causing data races between actor-isolated and task-isolated uses}}
 }
 
 // Redeclaration checking
 actor TestActor {
-  func test() { // expected-typechecker-note{{'test()' previously declared here}}
-  }
-#if ALLOW_TYPECHECKER_ERRORS
-  nonisolated func test() { // expected-typechecker-error{{invalid redeclaration of 'test()'}}
+  func test() {
   }
-#endif
 }
 
-#if ALLOW_TYPECHECKER_ERRORS
-
-func redecl(_: TestActor) { } // expected-typechecker-note{{'redecl' previously declared here}}
-func redecl(_: isolated TestActor) { } // expected-typechecker-error{{invalid redeclaration of 'redecl'}}
-
-#endif
-
-func tuplify<Ts>(_ fn: (Ts) -> Void) {} // expected-typechecker-note {{in call to function 'tuplify'}}
-
-#if ALLOW_TYPECHECKER_ERRORS
-
-@available(SwiftStdlib 5.1, *)
-func testTuplingIsolated(
-                         _ a: isolated A, // expected-typechecker-note {{previous 'isolated' parameter 'a'}}
-                         _ b: isolated A  // expected-typechecker-warning {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-                        ) {
-  tuplify(testTuplingIsolated)
-  // expected-typechecker-error@-1 {{generic parameter 'Ts' could not be inferred}}
-  // expected-typechecker-error@-2 {{cannot convert value of type '(isolated A, isolated A) -> ()' to expected argument type '(Ts) -> Void'}}
-}
-
-#endif
+func tuplify<Ts>(_ fn: (Ts) -> Void) {}
 
 // Inference of "isolated" on closure parameters.
 @available(SwiftStdlib 5.1, *)
@@ -232,54 +117,13 @@ func testIsolatedClosureInference(one: A, two: A) async {
   let _: (isolated A) -> Void = { (a2: isolated A) in
     a2.f()
   }
-
-#if ALLOW_TYPECHECKER_ERRORS
-  let f: (isolated A, isolated A) -> Void = // expected-typechecker-warning {{function type cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-      // expected-typechecker-note@+2 {{previous 'isolated' parameter 'a1'}}
-      // expected-typechecker-warning@+1 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-      { (a1, a2) in
-        a1.f()
-        a2.f()
-      }
-
-  await f(one, two)
-
-  let g: (isolated A, isolated A) -> Void = // expected-typechecker-warning {{function type cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-      // expected-typechecker-note@+2 {{previous 'isolated' parameter '$0'}}
-      // expected-typechecker-warning@+1 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-      {
-        $0.f()
-        $1.f()
-      }
-
-  await g(one, two)
-  #endif
 }
 
-#if ALLOW_TYPECHECKER_ERRORS
-
-struct CheckIsolatedFunctionTypes {
-  // expected-typechecker-warning@+2 {{function type cannot have global actor and 'isolated' parameter; this is an error in the Swift 6 language mode}}
-  // expected-typechecker-warning@+1 {{function type cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-  func a(_ f: @MainActor @Sendable (isolated A, isolated A) -> ()) {}
-
-  // expected-typechecker-note@+2 {{calls to parameter 'callback' from outside of its actor context are implicitly asynchronous}}
-  // expected-typechecker-warning@+1 {{function type cannot have global actor and 'isolated' parameter; this is an error in the Swift 6 language mode}}
-  @MainActor func update<R>(_ callback: @Sendable @escaping @MainActor (isolated A) -> R) -> R {
-    callback(A()) // expected-typechecker-error {{call to actor-isolated parameter 'callback' in a synchronous main actor-isolated context}}
-  }
-}
-
-#endif
-
 @available(SwiftStdlib 5.1, *)
 func checkIsolatedAndGlobalClosures(_ a: A) {
   let _: @MainActor (isolated A) -> Void // expected-warning {{function type cannot have global actor and 'isolated' parameter; this is an error in the Swift 6 language mode}}
       = {
     $0.f()
-    #if ALLOW_TYPECHECKER_ERRORS
-    mainActorFn() // expected-typechecker-error {{call to main actor-isolated global function 'mainActorFn()' in a synchronous actor-isolated context}}
-    #endif
   }
 
   let _: @MainActor (isolated A) -> Void // expected-warning {{function type cannot have global actor and 'isolated' parameter; this is an error in the Swift 6 language mode}}
@@ -287,16 +131,6 @@ func checkIsolatedAndGlobalClosures(_ a: A) {
     $0.f()
     mainActorFn()
   }
-
-#if ALLOW_TYPECHECKER_ERRORS
-  let _ = { @MainActor (a: isolated A, // expected-typechecker-warning {{closure with 'isolated' parameter 'a' cannot have a global actor; this is an error in the Swift 6 language mode}}{{13-24=}}
-                                       // expected-typechecker-note@-1 {{previous 'isolated' parameter 'a'}}
-                        b: isolated A, // expected-typechecker-warning {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-                        c: isolated A) async in
-    a.f()
-    mainActorFn()
-  }
-#endif
 }
 
 // "isolated" existential parameters.
@@ -308,24 +142,15 @@ protocol P2: Actor {
 func testExistentialIsolated(a: isolated P2, b: P2) async {
   a.m()
   await b.m()
-  #if ALLOW_TYPECHECKER_ERRORS
-  b.m() // expected-typechecker-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-typechecker-note@-1{{calls to instance method 'm()' from outside of its actor context are implicitly asynchronous}}
-  #endif
 }
 
 // "isolated" parameters of closures make the closure itself isolated.
 extension TestActor {
   func isolatedMethod() { }
-  // expected-typechecker-note@-1{{calls to instance method 'isolatedMethod()' from outside of its actor context are implicitly asynchronous}}
+ 
 
   // expected-warning@+1 {{instance method with 'isolated' parameter cannot be 'nonisolated'; this is an error in the Swift 6 language mode}}{{3-15=}}
   nonisolated func isolatedToParameter(_ other: isolated TestActor) {
-    #if ALLOW_TYPECHECKER_ERRORS
-    isolatedMethod()
-    // expected-typechecker-error@-1{{call to actor-isolated instance method 'isolatedMethod()' in a synchronous actor-isolated context}}
-    #endif
-
     other.isolatedMethod()
   }
 }
@@ -341,45 +166,6 @@ func isolatedClosures() {
   }
 }
 
-// expected-warning@+3 {{global function 'allOfEm' has multiple actor-isolation attributes (@MainActor and 'nonisolated')}}
-// expected-warning@+2 {{global function with 'isolated' parameter cannot be 'nonisolated'; this is an error in the Swift 6 language mode}}{{12-24=}}
-// expected-warning@+1 {{global function with 'isolated' parameter cannot have a global actor; this is an error in the Swift 6 language mode}}{{1-12=}}
-@MainActor nonisolated func allOfEm(_ a: isolated A) {
-  a.f()
-}
-
-#if ALLOW_TYPECHECKER_ERRORS
-
-@MainActor class MAClass {
-
-  // expected-typechecker-note@+2 {{previous 'isolated' parameter 'a'}}
-  // expected-typechecker-warning@+1 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-  init(_ a: isolated A, _ b: isolated A) {
-    // FIXME: wrong isolation. should be isolated to `a` only!
-    a.f()
-    b.f()
-  }
-
-  // expected-typechecker-note@+3 {{previous 'isolated' parameter 'a'}}
-  // expected-typechecker-warning@+2 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
-  // expected-typechecker-warning@+1 {{subscript with 'isolated' parameter cannot be 'nonisolated'; this is an error in the Swift 6 language mode}}{{3-15=}}
-  nonisolated subscript(_ a: isolated A, _ b: isolated A) -> Int {
-    // FIXME: wrong isolation. should be isolated to `a`.
-    #if ALLOW_TYPECHECKER_ERRORS
-    a.f() // expected-typechecker-error {{call to actor-isolated instance method 'f()' in a synchronous actor-isolated context}}
-    b.f() // expected-typechecker-error {{call to actor-isolated instance method 'f()' in a synchronous actor-isolated context}}
-    #endif
-    return 0
-  }
-
-  // expected-typechecker-warning@+1 {{instance method with 'isolated' parameter cannot be 'nonisolated'; this is an error in the Swift 6 language mode}}{{3-15=}}
-  nonisolated func millionDollars(_ a: isolated A) {
-    a.f()
-  }
-}
-
-#endif
-
 // Test case for https://github.com/apple/swift/issues/62568
 func execute<ActorType: Actor>(
   on isolatedActor: isolated ActorType,
@@ -409,25 +195,10 @@ func getValues(
   }
 }
 
-#if ALLOW_TYPECHECKER_ERRORS
-
-func isolated_generic_bad_1<T>(_ t: isolated T) {}
-// expected-typechecker-error@-1 {{'isolated' parameter type 'T' does not conform to 'Actor' or 'DistributedActor'}}
-func isolated_generic_bad_2<T: Equatable>(_ t: isolated T) {}
-// expected-typechecker-error@-1 {{'isolated' parameter type 'T' does not conform to 'Actor' or 'DistributedActor'}}
-func isolated_generic_bad_3<T: AnyActor>(_ t: isolated T) {}
-// expected-typechecker-error@-1 {{'isolated' parameter type 'T' does not conform to 'Actor' or 'DistributedActor'}}
-// expected-typechecker-warning@-2 {{'AnyActor' is deprecated: Use 'any Actor' with 'DistributedActor.asLocalActor' instead}}
-
-func isolated_generic_bad_4<T>(_ t: isolated Array<T>) {}
-// expected-typechecker-error@-1 {{'isolated' parameter type 'Array<T>' does not conform to 'Actor' or 'DistributedActor'}}
-
-#endif
-
 func isolated_generic_ok_1<T: Actor>(_ t: isolated T) {}
 
 
-class NotSendable {} // expected-complete-note 5 {{class 'NotSendable' does not conform to the 'Sendable' protocol}}
+class NotSendable {}
 
 func optionalIsolated(_ ns: NotSendable, to actor: isolated (any Actor)?) async {}
 func optionalIsolatedSync(_ ns: NotSendable, to actor: isolated (any Actor)?) {}
@@ -440,39 +211,23 @@ nonisolated func callFromNonisolated(ns: NotSendable) async {
   let myActor = A()
 
   await optionalIsolated(ns, to: myActor)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NotSendable' into actor-isolated context may introduce data races}}
-  // expected-tns-warning @-2 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-3 {{sending task-isolated 'ns' to actor-isolated global function 'optionalIsolated(_:to:)' risks causing data races between actor-isolated and task-isolated uses}}
-
-#if ALLOW_TYPECHECKER_ERRORS
-  optionalIsolatedSync(ns, to: myActor)
-  // expected-typechecker-error@-1 {{expression is 'async' but is not marked with 'await'}}
-  // expected-typechecker-note@-2 {{calls to global function 'optionalIsolatedSync(_:to:)' from outside of its actor context are implicitly asynchronous}}
-  // expected-complete-warning@-3 {{passing argument of non-sendable type 'NotSendable' into actor-isolated context may introduce data races}}
-  #endif
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns' to actor-isolated global function 'optionalIsolated(_:to:)' risks causing data races between actor-isolated and task-isolated uses}}
 }
 
 @MainActor func callFromMainActor(ns: NotSendable) async {
   await optionalIsolated(ns, to: nil)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NotSendable' outside of main actor-isolated context may introduce data races}}
-  // expected-tns-warning @-2 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-3 {{sending main actor-isolated 'ns' to nonisolated global function 'optionalIsolated(_:to:)' risks causing data races between nonisolated and main actor-isolated uses}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending main actor-isolated 'ns' to nonisolated global function 'optionalIsolated(_:to:)' risks causing data races between nonisolated and main actor-isolated uses}}
 
   optionalIsolatedSync(ns, to: nil)
 
   let myActor = A()
 
   await optionalIsolated(ns, to: myActor)
-  // expected-complete-warning@-1 {{passing argument of non-sendable type 'NotSendable' into actor-isolated context may introduce data races}}
-  // expected-tns-warning @-2 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-3 {{sending main actor-isolated 'ns' to actor-isolated global function 'optionalIsolated(_:to:)' risks causing data races between actor-isolated and main actor-isolated uses}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending main actor-isolated 'ns' to actor-isolated global function 'optionalIsolated(_:to:)' risks causing data races between actor-isolated and main actor-isolated uses}}
 
-#if ALLOW_TYPECHECKER_ERRORS
-  optionalIsolatedSync(ns, to: myActor)
-  // expected-typechecker-error@-1 {{expression is 'async' but is not marked with 'await'}}
-  // expected-typechecker-note@-2 {{calls to global function 'optionalIsolatedSync(_:to:)' from outside of its actor context are implicitly asynchronous}}
-  // expected-complete-warning@-3 {{passing argument of non-sendable type 'NotSendable' into actor-isolated context may introduce data races}}
-#endif
 }
 
 // TODO: Consider making an actor's Self behave like in a struct, removing this special casing.
@@ -480,12 +235,6 @@ nonisolated func callFromNonisolated(ns: NotSendable) async {
 //       See: https://github.com/apple/swift/issues/70954 and rdar://121091417
 actor A2 {
   nonisolated func f1() async {
-#if ALLOW_TYPECHECKER_ERRORS
-    await { (self: isolated Self) in }(self)
-    // expected-typechecker-error@-1 {{cannot convert value of type 'A2' to expected argument type 'Self'}}
-    await { (self: isolated Self?) in }(self)
-    // expected-typechecker-error@-1 {{cannot convert value of type 'A2' to expected argument type 'Self'}}
-#endif
   }
   nonisolated func f2() async -> Self {
     await { (self: isolated Self) in }(self)
@@ -502,9 +251,9 @@ func testNonSendableCaptures(ns: NotSendable, a: isolated MyActor) {
 
   // FIXME: The `a` in the capture list and `isolated a` are the same,
   // but the actor isolation checker doesn't know that.
-  Task { [a] in // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between 'a'-isolated code and concurrent execution of the closure}}
+  Task { [a] in // expected-warning {{passing closure as a 'sending' parameter risks causing data races between 'a'-isolated code and concurrent execution of the closure}}
     _ = a
-    _ = ns // expected-tns-note {{closure captures 'a'-isolated 'ns'}}
+    _ = ns // expected-note {{closure captures 'a'-isolated 'ns'}}
   }
 }
 
@@ -555,14 +304,6 @@ nonisolated func fromNonisolated(ns: NotSendable) async -> NotSendable {
   await pass(value: ns, isolation: nil)
 }
 
-#if ALLOW_TYPECHECKER_ERRORS
-
-func invalidIsolatedClosureParam<A: AnyActor> ( // expected-typechecker-warning {{'AnyActor' is deprecated: Use 'any Actor' with 'DistributedActor.asLocalActor' instead}}
-  _: (isolated A) async throws -> Void // expected-typechecker-error {{'isolated' parameter type 'A' does not conform to 'Actor' or 'DistributedActor'}}
-) {}
-
-#endif
-
 public func useDefaultIsolation(
   _ isolation: isolated (any Actor)? = #isolation
 ) {}
@@ -591,3 +332,14 @@ public actor MyActorIsolatedParameterMerge {
 class ClassWithIsolatedAsyncInitializer {
     init(isolation: isolated (any Actor)? = #isolation) async {}
 }
+
+// https://github.com/swiftlang/swift/issues/80992
+struct WritableActorKeyPath<Root: Actor, Value>: Sendable {
+    var getter: @Sendable (isolated Root) -> Value
+    var setter: @Sendable (isolated Root, Value) -> Void
+
+    subscript(_ root: isolated Root) -> Value {
+        get { getter(root) }
+        nonmutating set { setter(root, newValue) }
+    }
+}
diff --git a/test/Concurrency/isolated_parameters_typechecker_errors.swift b/test/Concurrency/isolated_parameters_typechecker_errors.swift
new file mode 100644
index 0000000000000..414741ba9f803
--- /dev/null
+++ b/test/Concurrency/isolated_parameters_typechecker_errors.swift
@@ -0,0 +1,517 @@
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete %s -emit-sil -o /dev/null -verify
+
+// REQUIRES: asserts
+// REQUIRES: concurrency
+// REQUIRES: swift_swift_parser
+
+@available(SwiftStdlib 5.1, *)
+actor A {
+  func f() { } // expected-note 3{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+}
+
+@available(SwiftStdlib 5.1, *)
+extension Actor {
+  func g() { }
+}
+
+@MainActor func mainActorFn() {} // expected-note {{calls to global function 'mainActorFn()' from outside of its actor context are implicitly asynchronous}}
+
+@available(SwiftStdlib 5.1, *)
+func testA<T: Actor>(
+  a: isolated A,  // expected-note {{previous 'isolated' parameter 'a'}}
+  b: isolated T,  // expected-warning {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+  c: isolated Int // expected-error {{'isolated' parameter type 'Int' does not conform to 'Actor' or 'DistributedActor'}}
+) {
+  a.f()
+  a.g()
+  b.g()
+}
+
+actor Other {
+  func inc() {}
+  func pass(_ f: @Sendable  (Self) async -> Void) {}
+}
+actor Counter {
+  func inc() {}
+  func pass(_ f: @Sendable  (Self) async -> Void) {}
+}
+
+// This is illegal at the SIL level so even though we could ignore this
+// note/warning, we will get a crash otherwise.
+@available(SwiftStdlib 5.1, *)
+// expected-note@+2 {{previous 'isolated' parameter 'a'}}
+// expected-warning@+1 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+func testDoubleIsolatedParams(a: isolated Counter, b: isolated Other) async {
+  a.inc()
+  b.inc()
+}
+
+func taaaa() async {
+  await Counter().pass { isoC in
+    await Other().pass { isoO in
+      await testDoubleIsolatedParams(a: isoC, b: isoO)
+    }
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+typealias Fn = (isolated A) -> Void
+
+@available(SwiftStdlib 5.1, *)
+func globalFunc(_ a: A) { }
+
+@available(SwiftStdlib 5.1, *)
+func globalFuncIsolated(_: isolated A) { // expected-note{{calls to global function 'globalFuncIsolated' from outside of its actor context are implicitly asynchronous}}
+  let _: Int = globalFuncIsolated // expected-error{{cannot convert value of type '(isolated A) -> ()' to specified type 'Int'}}
+  let _: (A) -> Void = globalFuncIsolated // expected-error{{cannot convert value of type '(isolated A) -> ()' to specified type '(A) -> Void'}}
+  let _: Fn = globalFunc // okay
+}
+
+@available(SwiftStdlib 5.1, *)
+// expected-warning@+1 {{global function with 'isolated' parameter cannot have a global actor; this is an error in the Swift 6 language mode}}{{1-12=}}
+@MainActor func testIsolatedParamCalls(a: isolated A, b: A) {
+  globalFunc(a)
+  globalFunc(b)
+
+  globalFuncIsolated(a)
+  globalFuncIsolated(b) // expected-error{{call to actor-isolated global function 'globalFuncIsolated' in a synchronous actor-isolated context}}
+}
+
+@available(SwiftStdlib 5.1, *)
+func testIsolatedParamCallsAsync(a: isolated A, b: A) async {
+  globalFunc(a)
+  globalFunc(b)
+
+  globalFuncIsolated(a)
+  globalFuncIsolated(b) // expected-error{{actor-isolated global function 'globalFuncIsolated' cannot be called from outside of the actor}} {{3-3=await }}
+  await globalFuncIsolated(b)
+}
+
+@available(SwiftStdlib 5.1, *)
+func testIsolatedParamCaptures(a: isolated A) async {
+  let _ = { @MainActor in
+    a.f() // expected-error {{call to actor-isolated instance method 'f()' in a synchronous main actor-isolated context}}
+  }
+
+  let _: @MainActor () -> () = {
+    a.f() // expected-error {{call to actor-isolated instance method 'f()' in a synchronous main actor-isolated context}}
+  }
+
+  let _ = {
+    a.f()
+  }
+
+  let _ = { @Sendable in
+    a.f() // expected-error {{call to actor-isolated instance method 'f()' in a synchronous nonisolated context}}
+  }
+}
+
+actor MyActor {
+  func hello() {} // expected-note {{calls to instance method 'hello()' from outside of its actor context are implicitly asynchronous}}
+}
+
+// Compiler >= 5.3 is ended to suppress the parser error
+#if compiler(>=5.3)
+typealias MyFn = (isolated: Int) -> Void // expected-error {{function types cannot have argument labels; use '_' before 'isolated'}}
+#endif
+typealias MyFnFixed = (_: isolated MyActor) -> Void
+
+func standalone(_: isolated MyActor) {}
+
+func check() {
+  let _: MyFnFixed = standalone
+  let _: MyFnFixed = { (_: isolated MyActor) in () }
+}
+
+
+@available(SwiftStdlib 5.1, *)
+protocol P {
+  func f(isolated: MyActor) async
+  func g(isolated x: MyActor) async
+  func h(isolated MyActor: isolated MyActor)
+  func i(isolated: isolated MyActor)
+  func j(isolated: Int) -> Int
+  func k(isolated y: Int) -> Int
+  func l(isolated _: Int) -> Int
+  func m(thing: isolated MyActor)
+}
+
+@available(SwiftStdlib 5.1, *)
+struct S: P {
+  func f(isolated: MyActor) async { await isolated.hello() }
+  func g(isolated x: MyActor) async { await x.hello() }
+  func h(isolated MyActor: isolated MyActor) { i(isolated: MyActor) }
+  func i(isolated: isolated MyActor) { isolated.hello() }
+  func j(isolated: Int) -> Int { return isolated }
+  func k(isolated y: Int) -> Int { return j(isolated: y) }
+  func l(isolated _: Int) -> Int { return k(isolated: 0) }
+  func m(thing: MyActor) { thing.hello() } // expected-error {{call to actor-isolated instance method 'hello()' in a synchronous nonisolated context}}
+}
+
+func checkConformer(_ s: S, _ p: any P, _ ma: MyActor) async {
+  s.m(thing: ma)
+  await p.m(thing: ma)
+}
+
+// Redeclaration checking
+actor TestActor {
+  func test() { // expected-note{{'test()' previously declared here}}
+  }
+  nonisolated func test() { // expected-error{{invalid redeclaration of 'test()'}}
+  }
+}
+
+func redecl(_: TestActor) { } // expected-note{{'redecl' previously declared here}}
+func redecl(_: isolated TestActor) { } // expected-error{{invalid redeclaration of 'redecl'}}
+
+func tuplify<Ts>(_ fn: (Ts) -> Void) {} // expected-note {{in call to function 'tuplify'}}
+
+@available(SwiftStdlib 5.1, *)
+func testTuplingIsolated(
+                         _ a: isolated A, // expected-note {{previous 'isolated' parameter 'a'}}
+                         _ b: isolated A  // expected-warning {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+                        ) {
+  tuplify(testTuplingIsolated)
+  // expected-error@-1 {{generic parameter 'Ts' could not be inferred}}
+  // expected-error@-2 {{cannot convert value of type '(isolated A, isolated A) -> ()' to expected argument type '(Ts) -> Void'}}
+}
+
+// Inference of "isolated" on closure parameters.
+@available(SwiftStdlib 5.1, *)
+func testIsolatedClosureInference(one: A, two: A) async {
+  let _: (isolated A) -> Void = {
+    $0.f()
+  }
+
+  let _: (isolated A) -> Void = {
+    $0.f()
+  }
+
+  let _: (isolated A) -> Void = { a2 in
+    a2.f()
+  }
+
+  let _: (isolated A) -> Void = { (a2: isolated A) in
+    a2.f()
+  }
+
+  let f: (isolated A, isolated A) -> Void = // expected-warning {{function type cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+      // expected-note@+2 {{previous 'isolated' parameter 'a1'}}
+      // expected-warning@+1 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+      { (a1, a2) in
+        a1.f()
+        a2.f()
+      }
+
+  await f(one, two)
+
+  let g: (isolated A, isolated A) -> Void = // expected-warning {{function type cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+      // expected-note@+2 {{previous 'isolated' parameter '$0'}}
+      // expected-warning@+1 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+      {
+        $0.f()
+        $1.f()
+      }
+
+  await g(one, two)
+}
+
+struct CheckIsolatedFunctionTypes {
+  // expected-warning@+2 {{function type cannot have global actor and 'isolated' parameter; this is an error in the Swift 6 language mode}}
+  // expected-warning@+1 {{function type cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+  func a(_ f: @MainActor @Sendable (isolated A, isolated A) -> ()) {}
+
+  // expected-note@+2 {{calls to parameter 'callback' from outside of its actor context are implicitly asynchronous}}
+  // expected-warning@+1 {{function type cannot have global actor and 'isolated' parameter; this is an error in the Swift 6 language mode}}
+  @MainActor func update<R>(_ callback: @Sendable @escaping @MainActor (isolated A) -> R) -> R {
+    callback(A()) // expected-error {{call to actor-isolated parameter 'callback' in a synchronous main actor-isolated context}}
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+func checkIsolatedAndGlobalClosures(_ a: A) {
+  let _: @MainActor (isolated A) -> Void // expected-warning {{function type cannot have global actor and 'isolated' parameter; this is an error in the Swift 6 language mode}}
+      = {
+    $0.f()
+    mainActorFn() // expected-error {{call to main actor-isolated global function 'mainActorFn()' in a synchronous actor-isolated context}}
+  }
+
+  let _: @MainActor (isolated A) -> Void // expected-warning {{function type cannot have global actor and 'isolated' parameter; this is an error in the Swift 6 language mode}}
+      = { @MainActor in // expected-warning {{closure with 'isolated' parameter '$0' cannot have a global actor; this is an error in the Swift 6 language mode}}{{11-22=}}
+    $0.f()
+    mainActorFn()
+  }
+
+  let _ = { @MainActor (a: isolated A, // expected-warning {{closure with 'isolated' parameter 'a' cannot have a global actor; this is an error in the Swift 6 language mode}}{{13-24=}}
+                                       // expected-note@-1 {{previous 'isolated' parameter 'a'}}
+                        b: isolated A, // expected-warning {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+                        c: isolated A) async in
+    a.f()
+    mainActorFn()
+  }
+}
+
+// "isolated" existential parameters.
+protocol P2: Actor {
+  func m()
+}
+
+@available(SwiftStdlib 5.1, *)
+func testExistentialIsolated(a: isolated P2, b: P2) async {
+  a.m()
+  await b.m()
+  b.m() // expected-error{{actor-isolated instance method 'm()' cannot be called from outside of the actor}} {{3-3=await }}
+}
+
+// "isolated" parameters of closures make the closure itself isolated.
+extension TestActor {
+  func isolatedMethod() { }
+  // expected-note@-1{{calls to instance method 'isolatedMethod()' from outside of its actor context are implicitly asynchronous}}
+
+  // expected-warning@+1 {{instance method with 'isolated' parameter cannot be 'nonisolated'; this is an error in the Swift 6 language mode}}{{3-15=}}
+  nonisolated func isolatedToParameter(_ other: isolated TestActor) {
+    isolatedMethod()
+    // expected-error@-1{{call to actor-isolated instance method 'isolatedMethod()' in a synchronous actor-isolated context}}
+
+    other.isolatedMethod()
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+func isolatedClosures() {
+  let _: (isolated TestActor) -> Void = { (ta: isolated TestActor) in
+    ta.isolatedMethod() // okay, isolated to ta
+
+    _ = {
+      ta.isolatedMethod() // okay, isolated to ta
+    }
+  }
+}
+
+// expected-error@+3 {{global function 'allOfEm' has multiple actor-isolation attributes (@MainActor and 'nonisolated')}}
+// expected-warning@+2 {{global function with 'isolated' parameter cannot be 'nonisolated'; this is an error in the Swift 6 language mode}}{{12-24=}}
+// expected-warning@+1 {{global function with 'isolated' parameter cannot have a global actor; this is an error in the Swift 6 language mode}}{{1-12=}}
+@MainActor nonisolated func allOfEm(_ a: isolated A) {
+  a.f()
+}
+
+@MainActor class MAClass {
+
+  // expected-note@+2 {{previous 'isolated' parameter 'a'}}
+  // expected-warning@+1 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+  init(_ a: isolated A, _ b: isolated A) {
+    // FIXME: wrong isolation. should be isolated to `a` only!
+    a.f()
+    b.f()
+  }
+
+  // expected-note@+3 {{previous 'isolated' parameter 'a'}}
+  // expected-warning@+2 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
+  // expected-warning@+1 {{subscript with 'isolated' parameter cannot be 'nonisolated'; this is an error in the Swift 6 language mode}}{{3-15=}}
+  nonisolated subscript(_ a: isolated A, _ b: isolated A) -> Int {
+    a.f()
+    b.f()
+    return 0
+  }
+
+  // expected-warning@+1 {{instance method with 'isolated' parameter cannot be 'nonisolated'; this is an error in the Swift 6 language mode}}{{3-15=}}
+  nonisolated func millionDollars(_ a: isolated A) {
+    a.f()
+  }
+}
+
+// Test case for https://github.com/apple/swift/issues/62568
+func execute<ActorType: Actor>(
+  on isolatedActor: isolated ActorType,
+  task: @escaping @Sendable (isolated ActorType) -> Void)
+{
+  // Compiler correctly allows this task to execute synchronously.
+  task(isolatedActor)
+  // Start a task that inherits the current execution context (i.e. that of the isolatedActor)
+  Task {
+    // 'await' is not not necessary because 'task' is synchronous.
+    task(isolatedActor)
+  }
+}
+
+actor ProtectsDictionary {
+  var dictionary: [String: String] = ["A": "B"]
+}
+
+func getValues(
+  forKeys keys: [String],
+  from actor: isolated ProtectsDictionary
+) -> [String?] {
+  // A non-escaping, synchronous closure cannot cross isolation
+  // boundaries; it should be isolated to 'actor'.
+  keys.map { key in
+    actor.dictionary[key]
+  }
+}
+
+func isolated_generic_bad_1<T>(_ t: isolated T) {}
+// expected-error@-1 {{'isolated' parameter type 'T' does not conform to 'Actor' or 'DistributedActor'}}
+func isolated_generic_bad_2<T: Equatable>(_ t: isolated T) {}
+// expected-error@-1 {{'isolated' parameter type 'T' does not conform to 'Actor' or 'DistributedActor'}}
+func isolated_generic_bad_3<T: AnyActor>(_ t: isolated T) {}
+// expected-error@-1 {{'isolated' parameter type 'T' does not conform to 'Actor' or 'DistributedActor'}}
+// expected-warning@-2 {{'AnyActor' is deprecated: Use 'any Actor' with 'DistributedActor.asLocalActor' instead}}
+
+func isolated_generic_bad_4<T>(_ t: isolated Array<T>) {}
+// expected-error@-1 {{'isolated' parameter type 'Array<T>' does not conform to 'Actor' or 'DistributedActor'}}
+
+func isolated_generic_ok_1<T: Actor>(_ t: isolated T) {}
+
+
+class NotSendable {} // expected-complete-note 5 {{class 'NotSendable' does not conform to the 'Sendable' protocol}}
+
+func optionalIsolated(_ ns: NotSendable, to actor: isolated (any Actor)?) async {}
+func optionalIsolatedSync(_ ns: NotSendable, to actor: isolated (any Actor)?) {}
+
+nonisolated func callFromNonisolated(ns: NotSendable) async {
+  await optionalIsolated(ns, to: nil)
+
+  optionalIsolatedSync(ns, to: nil)
+
+  let myActor = A()
+
+  await optionalIsolated(ns, to: myActor)
+
+  optionalIsolatedSync(ns, to: myActor)
+  // expected-error@-1 {{actor-isolated global function 'optionalIsolatedSync(_:to:)' cannot be called from outside of the actor}} {{3-3=await }}
+}
+
+@MainActor func callFromMainActor(ns: NotSendable) async {
+  await optionalIsolated(ns, to: nil)
+
+  optionalIsolatedSync(ns, to: nil)
+
+  let myActor = A()
+
+  await optionalIsolated(ns, to: myActor)
+
+  optionalIsolatedSync(ns, to: myActor)
+  // expected-error@-1 {{actor-isolated global function 'optionalIsolatedSync(_:to:)' cannot be called from outside of the actor}} {{3-3=await }}
+}
+
+// TODO: Consider making an actor's Self behave like in a struct, removing this special casing.
+//       We could consider changing this, so that self is always Self because we don't allow inheritance of actors.
+//       See: https://github.com/apple/swift/issues/70954 and rdar://121091417
+actor A2 {
+  nonisolated func f1() async {
+    await { (self: isolated Self) in }(self)
+    // expected-error@-1 {{cannot convert value of type 'A2' to expected argument type 'Self'}}
+    await { (self: isolated Self?) in }(self)
+    // expected-error@-1 {{cannot convert value of type 'A2' to expected argument type 'Self'}}
+  }
+  nonisolated func f2() async -> Self {
+    await { (self: isolated Self) in }(self)
+    await { (self: isolated Self?) in }(self)
+    return self
+  }
+}
+
+func testNonSendableCaptures(ns: NotSendable, a: isolated MyActor) {
+  Task {
+    _ = a
+    _ = ns
+  }
+
+  // FIXME: The `a` in the capture list and `isolated a` are the same,
+  // but the actor isolation checker doesn't know that.
+  Task { [a] in
+    _ = a
+    _ = ns
+  }
+}
+
+
+@globalActor actor MyGlobal {
+  static let shared = MyGlobal()
+}
+
+func sync(isolatedTo actor: isolated (any Actor)?) {}
+
+func pass(value: NotSendable, isolation: isolated (any Actor)?) async -> NotSendable {
+  value
+}
+
+func preciseIsolated(a: isolated MyActor) async {
+  sync(isolatedTo: a)
+  sync(isolatedTo: nil) // okay from anywhere
+  sync(isolatedTo: #isolation)
+
+  Task { @MainActor in
+    sync(isolatedTo: MainActor.shared)
+    sync(isolatedTo: nil) // okay from anywhere
+    sync(isolatedTo: #isolation)
+  }
+
+  Task { @MyGlobal in
+    sync(isolatedTo: MyGlobal.shared)
+    sync(isolatedTo: nil) // okay from anywhere
+    sync(isolatedTo: #isolation)
+  }
+
+  Task.detached {
+    sync(isolatedTo: nil) // okay from anywhere
+    sync(isolatedTo: #isolation)
+  }
+}
+
+func testLValueIsolated() async {
+  var a = A() // expected-warning {{variable 'a' was never mutated}}
+  await sync(isolatedTo: a)
+}
+
+@MainActor func fromMain(ns: NotSendable) async -> NotSendable {
+  await pass(value: ns, isolation: MainActor.shared)
+}
+
+nonisolated func fromNonisolated(ns: NotSendable) async -> NotSendable {
+  await pass(value: ns, isolation: nil)
+}
+
+func invalidIsolatedClosureParam<A: AnyActor> ( // expected-warning {{'AnyActor' is deprecated: Use 'any Actor' with 'DistributedActor.asLocalActor' instead}}
+  _: (isolated A) async throws -> Void // expected-error {{'isolated' parameter type 'A' does not conform to 'Actor' or 'DistributedActor'}}
+) {}
+
+public func useDefaultIsolation(
+  _ isolation: isolated (any Actor)? = #isolation
+) {}
+
+public func useDefaultIsolationWithoutIsolatedParam(
+  _ isolation: (any Actor)? = #isolation
+) {}
+
+@MainActor func callUseDefaultIsolation() async {
+  useDefaultIsolation()
+  useDefaultIsolationWithoutIsolatedParam()
+}
+
+public actor MyActorIsolatedParameterMerge {
+  private var inProgressIndexTasks: [Int: Int] = [:]
+
+  public func test() async {
+    await withTaskGroup(of: Void.self) { taskGroup in
+      for (_, _) in inProgressIndexTasks {}
+      await taskGroup.waitForAll()
+    }
+  }
+}
+
+// rdar://138394497
+class ClassWithIsolatedAsyncInitializer {
+    init(isolation: isolated (any Actor)? = #isolation) async {}
+}
+
+// https://github.com/swiftlang/swift/issues/80992
+struct WritableActorKeyPath<Root: Actor, Value>: Sendable {
+    var getter: @Sendable (isolated Root) -> Value
+    var setter: @Sendable (isolated Root, Value) -> Void
+
+    subscript(_ root: isolated Root) -> Value {
+        get { getter(root) }
+        nonmutating set { setter(root, newValue) }
+    }
+}
diff --git a/test/Concurrency/isolation_macro_availability.swift b/test/Concurrency/isolation_macro_availability.swift
index e038c10d387c3..68fc6473db653 100644
--- a/test/Concurrency/isolation_macro_availability.swift
+++ b/test/Concurrency/isolation_macro_availability.swift
@@ -10,7 +10,7 @@
 @available(SwiftStdlib 5.1, *)
 func isolatedFunc(isolation: isolated (any Actor)? = #isolation) {}
 
-func test() { // expected-note 3 {{add @available attribute to enclosing global function}}
+func test() { // expected-note 3 {{add '@available' attribute to enclosing global function}}
   _ = #isolation // expected-error {{'isolation()' is only available in}} expected-note {{add 'if #available' version check}}
   isolatedFunc() // expected-error {{'isolatedFunc(isolation:)' is only available in}} expected-note {{add 'if #available' version check}}
   // expected-error@-1 {{'isolation()' is only available in}}
diff --git a/test/Concurrency/isolation_macro_sil.swift b/test/Concurrency/isolation_macro_sil.swift
new file mode 100644
index 0000000000000..0c0216cd87118
--- /dev/null
+++ b/test/Concurrency/isolation_macro_sil.swift
@@ -0,0 +1,132 @@
+// RUN: %target-swift-frontend -parse-as-library -emit-sil %s -module-name test | %FileCheck %s
+
+// REQUIRES: concurrency
+
+nonisolated(nonsending) func nonisolatedNonsending() async {
+  let iso = #isolation
+  take(iso: iso)
+}
+
+func take(iso: (any Actor)?) {}
+
+func takeDefaulted(iso: isolated (any Actor)? = #isolation) {}
+
+// CHECK-LABEL: // nonisolatedNonsending()
+// CHECK-NEXT: // Isolation: caller_isolation_inheriting
+// CHECK-NEXT: sil hidden @$s4test21nonisolatedNonsendingyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// CHECK:      bb0([[ACTOR:%.*]] : $Optional<any Actor>):
+// CHECK:   retain_value [[ACTOR]]
+// CHECK:   debug_value [[ACTOR]], let, name "iso"
+// CHECK:   [[FUNC:%.*]] = function_ref @$s4test4take3isoyScA_pSg_tF : $@convention(thin) (@guaranteed Optional<any Actor>) -> ()
+// CHECK:   apply [[FUNC]]([[ACTOR]]) : $@convention(thin) (@guaranteed Optional<any Actor>) -> ()
+// CHECK:   release_value [[ACTOR]]
+// CHECK: } // end sil function '$s4test21nonisolatedNonsendingyyYaF'
+
+//   Check that we emit #isolation correctly in closures.
+// CHECK-LABEL: // closure #1 in containsClosure()
+// CHECK-NEXT:  // Isolation: caller_isolation_inheriting
+// CHECK:       bb0(%0 : $Optional<any Actor>):
+// CHECK-NEXT:    // function_ref take(iso:)
+// CHECK-NEXT:    [[FN:%.*]] = function_ref @
+// CHECK-NEXT:    apply [[FN]](%0)
+func containsClosure() {
+  let closure: nonisolated(nonsending) () async -> Void = {
+    take(iso: #isolation)
+  }
+}
+
+//   Check that we capture variables as necessary to emit #isolation
+//   correctly in defer bodies.
+func deferWithIsolatedParam(_ iso: isolated (any Actor)) {
+  defer {
+    take(iso: #isolation)
+  }
+  do {}
+}
+// CHECK-LABEL: sil hidden @$s4test22deferWithIsolatedParamyyScA_pYiF :
+// CHECK:       bb0(%0 : $any Actor)
+// CHECK:         [[DEFER:%.*]] = function_ref @$s4test22deferWithIsolatedParamyyScA_pYiF6$deferL_yyF :
+// CHECK-NEXT:    apply [[DEFER]](%0)
+
+// CHECK-LABEL: sil private @$s4test22deferWithIsolatedParamyyScA_pYiF6$deferL_yyF :
+// CHECK:       bb0(%0 : @closureCapture $any Actor):
+// CHECK:         [[T0:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, %0
+// CHECK:         [[FN:%.*]] = function_ref @$s4test4take3isoyScA_pSg_tF :
+// CHECK-NEXT:    apply [[FN]]([[T0]])
+
+//   Check that that happens even with uses in caller-side default
+//   arguments, which capture analysis was not previously walking into.
+func deferWithIsolatedParam_defaultedUse(_ iso: isolated (any Actor)) {
+  defer {
+    takeDefaulted()
+  }
+  do {}
+}
+
+// CHECK-LABEL: sil hidden @$s4test35deferWithIsolatedParam_defaultedUseyyScA_pYiF :
+// CHECK:       bb0(%0 : $any Actor):
+// CHECK:         [[DEFER:%.*]] = function_ref @$s4test35deferWithIsolatedParam_defaultedUseyyScA_pYiF6$deferL_yyF :
+// CHECK-NEXT:    apply [[DEFER]](%0)
+
+// CHECK-LABEL: sil private @$s4test35deferWithIsolatedParam_defaultedUseyyScA_pYiF6$deferL_yyF :
+// CHECK:       bb0(%0 : @closureCapture $any Actor):
+// CHECK:         [[T0:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, %0
+// CHECK:         [[FN:%.*]] = function_ref @$s4test13takeDefaulted3isoyScA_pSgYi_tF :
+// CHECK-NEXT:    apply [[FN]]([[T0]])
+
+// TODO: we can't currently call nonisolated(nonsending) functions in
+// defer bodies because they have to be async, but that should be
+// tested here as well.
+
+//   Check that we emit #isolation correctly in defer bodies.
+nonisolated(nonsending)
+func hasDefer() async {
+  defer {
+    take(iso: #isolation)
+  }
+  do {}
+}
+// CHECK-LABEL: sil hidden @$s4test8hasDeferyyYaF :
+// CHECK:       bb0(%0 : $Optional<any Actor>):
+// CHECK:         // function_ref $defer
+// CHECK-NEXT:    [[DEFER:%.*]] = function_ref
+// CHECK-NEXT:    apply [[DEFER]](%0)
+
+// CHECK-LABEL: // $defer #1 () in hasDefer()
+// CHECK-NEXT:  // Isolation: caller_isolation_inheriting
+// CHECK:       bb0(%0 : $Optional<any Actor>):
+// CHECK-NEXT:    // function_ref take(iso:)
+// CHECK-NEXT:    [[FN:%.*]] = function_ref @
+// CHECK-NEXT:    apply [[FN]](%0)
+
+//   Check that we emit #isolation correctly in nested defer bodies.
+nonisolated(nonsending)
+func hasNestedDefer() async {
+  defer {
+    defer {
+      take(iso: #isolation)
+    }
+    do {}
+  }
+  do {}
+}
+
+// CHECK-LABEL: sil hidden @$s4test14hasNestedDeferyyYaF :
+// CHECK:       bb0(%0 : $Optional<any Actor>):
+// CHECK:         // function_ref $defer #1 () in hasNestedDefer()
+// CHECK-NEXT:    [[DEFER:%.*]] = function_ref
+// CHECK-NEXT:    apply [[DEFER]](%0)
+
+// CHECK-LABEL: // $defer #1 () in hasNestedDefer()
+// CHECK-NEXT:  // Isolation: caller_isolation_inheriting
+// CHECK:       bb0(%0 : $Optional<any Actor>):
+// CHECK:         // function_ref $defer #1 () in $defer #1 () in hasNestedDefer()
+// CHECK-NEXT:    [[DEFER:%.*]] = function_ref
+// CHECK-NEXT:    apply [[DEFER]](%0)
+
+// CHECK-LABEL: // $defer #1 () in $defer #1 () in hasNestedDefer()
+// CHECK-NEXT:  // Isolation: caller_isolation_inheriting
+// CHECK:       bb0(%0 : $Optional<any Actor>):
+// CHECK-NEXT:    // function_ref take(iso:)
+// CHECK-NEXT:    [[FN:%.*]] = function_ref @
+// CHECK-NEXT:    apply [[FN]](%0)
diff --git a/test/Concurrency/issue-70019.swift b/test/Concurrency/issue-70019.swift
index 7a113384bd79e..ba86f5c321ccc 100644
--- a/test/Concurrency/issue-70019.swift
+++ b/test/Concurrency/issue-70019.swift
@@ -12,5 +12,5 @@ struct Foo { // expected-note {{consider making struct 'Foo' conform to the 'Sen
 
 struct Bar: Sendable {
   // FIXME: This warning should only be thrown in library evolution mode. If @usableFromInline is removed from Foo the Sendable conformance is synthesized as expected.
-  var foo: Foo // expected-warning {{stored property 'foo' of 'Sendable'-conforming struct 'Bar' has non-sendable type 'Foo'}}
+  var foo: Foo // expected-warning {{stored property 'foo' of 'Sendable'-conforming struct 'Bar' has non-Sendable type 'Foo'}}
 }
diff --git a/test/Concurrency/issue-80363.swift b/test/Concurrency/issue-80363.swift
new file mode 100644
index 0000000000000..7fdaadda2a469
--- /dev/null
+++ b/test/Concurrency/issue-80363.swift
@@ -0,0 +1,47 @@
+// RUN: %target-typecheck-verify-swift
+
+// https://github.com/swiftlang/swift/issues/80363
+
+class C {}
+
+func testLocal() {
+  isolated let c = C()
+  // expected-error@-1 {{'isolated' may only be used on 'deinit' declarations}}
+  _ = c
+
+  isolated func test() {
+    // expected-error@-1 {{'isolated' may only be used on 'deinit' declarations}}
+  }
+}
+
+isolated var x: Int = 42
+// expected-error@-1 {{'isolated' may only be used on 'deinit' declarations}}
+
+isolated class Test {
+  // expected-error@-1 {{'isolated' may only be used on 'deinit' declarations}}
+}
+
+struct TestMembers {
+  isolated var q: String {
+    // expected-error@-1 {{'isolated' may only be used on 'deinit' declarations}}
+    get {
+      "ultimate question"
+    }
+
+    isolated set {
+      // expected-error@-1 {{expected 'get', 'set', 'willSet', or 'didSet' keyword to start an accessor definition}}
+    }
+  }
+
+  isolated let a: Int = 42
+  // expected-error@-1 {{'isolated' may only be used on 'deinit' declarations}}
+
+  isolated subscript(x: Int) -> Bool {
+    // expected-error@-1 {{'isolated' may only be used on 'deinit' declarations}}
+    get { true }
+  }
+
+  isolated func test() {
+    // expected-error@-1 {{'isolated' may only be used on 'deinit' declarations}}
+  }
+}
diff --git a/test/Concurrency/local_functions.swift b/test/Concurrency/local_functions.swift
new file mode 100644
index 0000000000000..c409a7d483fee
--- /dev/null
+++ b/test/Concurrency/local_functions.swift
@@ -0,0 +1,62 @@
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o - -verify -strict-concurrency=complete -enable-actor-data-race-checks -disable-availability-checking | %FileCheck %s
+
+// Issue #80772. This used to crash in SILGen because we gave local functions
+// the isolation of their enclosing context instead of trying to convert
+// parameter isolation to capture isolation.
+actor TestActor {
+  // CHECK-LABEL: // nested #1 () in TestActor.testWithoutCapture()
+  // CHECK-NEXT:  // Isolation: actor_instance. name: 'self'
+  func testWithoutCapture() {
+    func nested() -> String {
+      return "test"
+    }
+
+    print(nested())
+  }
+
+  // CHECK-LABEL: // nested #1 () in TestActor.testWithCapture()
+  // CHECK-NEXT:  // Isolation: actor_instance. name: 'self'
+  // CHECK:       [[SELF_EXECUTOR:%.*]] = extract_executor %0
+  // CHECK:       [[CHECK_FN:%.*]] = function_ref @swift_task_isCurrentExecutor
+  // CHECK:       apply [[CHECK_FN]]([[SELF_EXECUTOR]])
+  func testWithCapture() {
+    func nested() -> String {
+      _ = self
+      return "test"
+    }
+
+    print(nested())
+  }
+}
+
+@globalActor struct GenericGlobalActor<T> {
+  static var shared: TestActor {
+    // not a valid implementation
+    return TestActor()
+  }
+}
+
+struct Generic<T> {
+  // CHECK-LABEL: // nested #1 <A><A1>(_:) in Generic.testGenericGlobalActor()
+  // CHECK-NEXT:  // Isolation: global_actor. type: GenericGlobalActor<T>
+  @GenericGlobalActor<T> func testGenericGlobalActor() {
+    func nested<U>(_ type: U.Type) -> String {
+      // CHECK: [[FN:%.*]] = function_ref @$s15local_functions18GenericGlobalActorV6sharedAA04TestE0CvgZ
+      // CHECK: apply [[FN]]<T>(
+      return "test"
+    }
+
+    print(nested(Int.self))
+  }
+}
+
+actor MyActor {
+  // CHECK-LABEL: // nested #1 () in MyActor.deinit
+  // CHECK-NEXT:  // Isolation: actor_instance. name: 'self'
+  isolated deinit {
+    func nested() -> String {
+      return "test"
+    }
+    print(nested())
+  }
+}
diff --git a/test/Concurrency/metatype_crasher.swift b/test/Concurrency/metatype_crasher.swift
new file mode 100644
index 0000000000000..e78d256dfacf2
--- /dev/null
+++ b/test/Concurrency/metatype_crasher.swift
@@ -0,0 +1,65 @@
+// RUN: %target-typecheck-verify-swift -swift-version 6
+
+// REQUIRES: concurrency
+
+struct MyType<T: Sendable> : Sendable {
+    enum MyError: Error {
+        case error
+    }
+
+    public init(_ h: T) { self.handler = h }
+
+    public var handler: T
+
+    public func handle<OperationInput, OperationOutput>(
+      forOperation operationID: String,
+      using handlerMethod: @Sendable @escaping (T)
+        -> ((OperationInput) async throws -> OperationOutput),
+      deserializer: @Sendable @escaping (
+      ) throws -> OperationInput,
+      serializer: @Sendable @escaping (OperationOutput) throws
+        -> ()
+    ) async throws -> () where OperationInput: Sendable,
+                               OperationOutput: Sendable
+    {
+        @Sendable
+        func wrappingErrors<R>(
+          work: () async throws -> R,
+          mapError: (any Error) -> any Error
+        ) async throws -> R {
+            fatalError()
+        }
+        @Sendable
+        func makeError(
+          input: OperationInput? = nil,
+          output: OperationOutput? = nil,
+          error: any Error
+        ) -> any Error {
+            fatalError()
+        }
+        var next: @Sendable () async throws // expected-warning {{}}
+          -> () = {
+              let input: OperationInput = try await wrappingErrors {
+                  try deserializer()
+              } mapError: { error in
+                  makeError(error: error)
+              }
+              let output: OperationOutput = try await wrappingErrors {
+                  let method = handlerMethod(handler)
+                  return try await wrappingErrors {
+                      try await method(input)
+                  } mapError: { error in
+                      MyError.error
+                  }
+              } mapError: { error in
+                  makeError(input: input, error: error)
+              }
+              return try await wrappingErrors {
+                  try serializer(output)
+              } mapError: { error in
+                  makeError(input: input, output: output, error: error)
+              }
+          }
+        return try await next()
+    }
+}
diff --git a/test/Concurrency/nonisolated_access.swift b/test/Concurrency/nonisolated_access.swift
index 3f9731b648e97..6aecb6fcdf23c 100644
--- a/test/Concurrency/nonisolated_access.swift
+++ b/test/Concurrency/nonisolated_access.swift
@@ -3,13 +3,13 @@
 
 /// Build the library A
 // RUN: %target-swift-frontend -emit-module %t/src/A.swift \
-// RUN: -target %target-swift-5.1-abi-triple -verify \
+// RUN: -target %target-swift-5.1-abi-triple -verify -verify-ignore-unrelated \
 // RUN: -module-name A -swift-version 6 \
 // RUN: -emit-module-path %t/A.swiftmodule
 
 // Build the client
 // RUN: %target-swift-frontend -emit-module %t/src/Client.swift \
-// RUN: -target %target-swift-5.1-abi-triple -verify \
+// RUN: -target %target-swift-5.1-abi-triple -verify -verify-ignore-unrelated \
 // RUN: -module-name Client -I %t -swift-version 6 \
 // RUN: -emit-module-path %t/Client.swiftmodule
 
diff --git a/test/Concurrency/nonisolated_inherits_isolation.swift b/test/Concurrency/nonisolated_inherits_isolation.swift
index 6916275e99713..82dc816633761 100644
--- a/test/Concurrency/nonisolated_inherits_isolation.swift
+++ b/test/Concurrency/nonisolated_inherits_isolation.swift
@@ -1,11 +1,11 @@
 // RUN: %target-swift-frontend %s -swift-version 6 -verify -verify-additional-prefix disabled- -c
-// RUN: %target-swift-frontend %s -swift-version 6 -verify -enable-experimental-feature AsyncCallerExecution -verify-additional-prefix enable- -c -verify-additional-prefix enabled-
+// RUN: %target-swift-frontend %s -swift-version 6 -verify -enable-upcoming-feature NonisolatedNonsendingByDefault -verify-additional-prefix enable- -c -verify-additional-prefix enabled-
 
 // REQUIRES: asserts
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_AsyncCallerExecution
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
-// This test checks and validates that when AsyncCallerExecution is enabled, we emit the
+// This test checks and validates that when NonisolatedNonsendingByDefault is enabled, we emit the
 // appropriate diagnostics. It also runs with the mode off so we can validate
 // and compare locally against the normal errors.
 
@@ -13,7 +13,12 @@
 // Declarations //
 //////////////////
 
-class NonSendableKlass {}
+class NonSendableKlass {
+  func unspecifiedCaller() async {}
+  nonisolated func nonisolatedCaller() async {}
+  nonisolated(nonsending) func nonisolatedNonSendingCaller() async {}
+  @concurrent func concurrentCaller() async {}
+}
 
 nonisolated class NonIsolatedNonSendableKlass {
   func unspecifiedMethod() async {}
@@ -24,6 +29,8 @@ func unspecifiedSyncUse<T>(_ t: T) {}
 func unspecifiedAsyncUse<T>(_ t: T) async {}
 nonisolated func nonisolatedSyncUse<T>(_ t: T) {}
 nonisolated func nonisolatedAsyncUse<T>(_ t: T) async {}
+nonisolated(nonsending) func nonisolatedNonSendingAsyncUse<T>(_ t: T) async {}
+@concurrent func concurrentAsyncUse<T>(_ t: T) async {}
 
 func unspecifiedSyncUseWithResult<T>(_ t: T) -> T { t }
 func unspecifiedAsyncUseWithResult<T>(_ t: T) async -> T { t }
@@ -34,6 +41,8 @@ func unspecifiedSyncResult() -> NonSendableKlass { fatalError() }
 func unspecifiedAsyncResult() async -> NonSendableKlass { fatalError() }
 nonisolated func nonisolatedSyncResult() -> NonSendableKlass { fatalError() }
 nonisolated func nonisolatedAsyncResult() async -> NonSendableKlass { fatalError() }
+func sendingParameter<T>(_ t: sending T) async {}
+func useValue<T>(_ t: T) {}
 
 @MainActor func sendToMain<T>(_ t: T) async {}
 
@@ -49,6 +58,13 @@ struct CustomActor {
 
 @CustomActor func sendToCustom<T>(_ t: T) async {}
 
+@MainActor
+final class MainActorKlass {
+  var ns = NonSendableKlass()
+
+  func useValueAsync(_ x: NonSendableKlass) async {}
+}
+
 ///////////
 // Tests //
 ///////////
@@ -90,22 +106,17 @@ actor ActorTest {
     await sendToMain(x1)
 
     let x2 = await unspecifiedAsyncResult()
-    await sendToMain(x2) // expected-enabled-error {{sending 'x2' risks causing data races}}
-    // expected-enabled-note @-1 {{sending 'self'-isolated 'x2' to main actor-isolated global function 'sendToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    await sendToMain(x2)
 
     let x3 = nonisolatedSyncResult()
     await sendToMain(x3)
 
     let x4 = await nonisolatedAsyncResult()
-    await sendToMain(x4) // expected-enabled-error {{sending 'x4' risks causing data races}}
-    // expected-enabled-note @-1 {{sending 'self'-isolated 'x4' to main actor-isolated global function 'sendToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    await sendToMain(x4)
   }
 }
 
-@MainActor
-class MainActorKlass {
-  var ns = NonSendableKlass()
-
+extension MainActorKlass {
   func callNonIsolatedWithParam() async {
     unspecifiedSyncUse(ns)
     await unspecifiedAsyncUse(ns) // expected-disabled-error {{sending 'self.ns' risks causing data races}}
@@ -141,15 +152,13 @@ class MainActorKlass {
     await sendToCustom(x1)
 
     let x2 = await unspecifiedAsyncResult()
-    await sendToCustom(x2) // expected-enabled-error {{sending 'x2' risks causing data races}}
-    // expected-enabled-note @-1 {{sending main actor-isolated 'x2' to global actor 'CustomActor'-isolated global function 'sendToCustom' risks causing data races between global actor 'CustomActor'-isolated and main actor-isolated uses}}
+    await sendToCustom(x2)
 
     let x3 = nonisolatedSyncResult()
     await sendToCustom(x3)
 
     let x4 = await nonisolatedAsyncResult()
-    await sendToCustom(x4) // expected-enabled-error {{sending 'x4' risks causing data races}}
-    // expected-enabled-note @-1 {{sending main actor-isolated 'x4' to global actor 'CustomActor'-isolated global function 'sendToCustom' risks causing data races between global actor 'CustomActor'-isolated and main actor-isolated uses}}
+    await sendToCustom(x4)
   }
 }
 
@@ -166,3 +175,171 @@ func validateNonisolatedOnClassMeansCallerIsolationInheritingOnFuncDecl(
   await c.nonisolatedMethod() // expected-disabled-error {{sending 'c' risks causing data races}}
   // expected-disabled-note @-1 {{sending main actor-isolated 'c' to nonisolated instance method 'nonisolatedMethod()' risks causing data races between nonisolated and main actor-isolated uses}}
 }
+
+// Shouldn't get an error here since we are not using after we send to main.
+func nonisolatedCallingNonIsolated() async {
+  let c = NonSendableKlass()
+
+  await unspecifiedAsyncUse(c)
+  await unspecifiedAsyncUse(c)
+
+  await sendToMain(c)
+}
+
+func nonisolatedCallingNonIsolated2() async {
+  let c = NonSendableKlass()
+
+  await unspecifiedAsyncUse(c)
+  await unspecifiedAsyncUse(c)
+
+  await sendToMain(c) // expected-error {{sending 'c' risks causing data races}}
+  // expected-note @-1 {{sending 'c' to main actor-isolated global function 'sendToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+
+  await unspecifiedAsyncUse(c) // expected-note {{access can happen concurrently}}
+}
+
+// We should emit an error here despite the function context being @MainActor.
+@MainActor
+func sendingWithMainActor() async {
+  let c = NonSendableKlass()
+  await sendingParameter(c) // expected-error {{sending 'c' risks causing data races}}
+  // expected-note @-1 {{'c' used after being passed as a 'sending' parameter}}
+  useValue(c) // expected-note {{access can happen concurrently}}
+}
+
+// We should emit an error here despite the function context have an explicit
+// isolated parameter.
+func sendingWithIsolatedParam(_ a: isolated Optional<Actor>) async {
+  let c = NonSendableKlass()
+  await sendingParameter(c) // expected-error {{sending 'c' risks causing data races}}
+  // expected-note @-1 {{'c' used after being passed as a 'sending' parameter}}
+  useValue(c) // expected-note {{access can happen concurrently}}
+}
+
+// This errors only when disabled since the first time we call
+// unspecifiedAsyncUse we have a disconnected value and the second time we have
+// a value in a main actor isolated region and the unspecifiedAsyncUse runs on
+// the main actor.
+//
+// TODO: This doesn't error if we have a non-final class because of a known bug
+// where we infer isolation wrong for non-final class setters. That is why
+// MainActorKlass is made final so we can test this appropriately.
+@MainActor
+func testUnrolledLoop(_ a: MainActorKlass) async {
+  let k = NonSendableKlass()
+  await unspecifiedAsyncUse(k)
+  a.ns = k
+  await unspecifiedAsyncUse(k) // expected-disabled-error {{sending 'k' risks causing data races}}
+  // expected-disabled-note @-1 {{sending main actor-isolated 'k' to nonisolated global function 'unspecifiedAsyncUse' risks causing data races between nonisolated and main actor-isolated uses}}
+}
+
+// We emit an error in both modes since we are now in an @MainActor isolated
+// function.
+func testUnrolledLoop2(_ a: MainActorKlass) async {
+  let k = NonSendableKlass()
+  await unspecifiedAsyncUse(k)
+  await a.useValueAsync(k) // expected-error {{sending 'k' risks causing data races}}
+  // expected-note @-1 {{sending 'k' to main actor-isolated instance method 'useValueAsync' risks causing data races between main actor-isolated and local nonisolated uses}}
+  await unspecifiedAsyncUse(k) // expected-note {{access can happen concurrently}}
+}
+
+func testUnrolledLoopWithAsyncLet(_ a: MainActorKlass) async {
+  let k = NonSendableKlass()
+  await unspecifiedAsyncUse(k)
+  // This is valid since our valid is disconnected here.
+  async let value: () = await unspecifiedAsyncUse(k)
+  _ = await value
+
+  await a.useValueAsync(k) // expected-error {{sending 'k' risks causing data races}}
+  // expected-note @-1 {{sending 'k' to main actor-isolated instance method 'useValueAsync' risks causing data races between main actor-isolated and local nonisolated uses}}
+  async let value2: () = await unspecifiedAsyncUse(k) // expected-note {{access can happen concurrently}}
+  _ = await value2
+}
+
+@MainActor
+func testUnrolledLoopWithAsyncLet2(_ a: MainActorKlass) async {
+  let k = NonSendableKlass()
+  await unspecifiedAsyncUse(k)
+  // This is valid since our valid is disconnected here.
+  async let value: () = await unspecifiedAsyncUse(k)
+  _ = await value
+
+  await a.useValueAsync(k)
+  async let value2: () = await unspecifiedAsyncUse(k) // expected-error {{sending 'k' risks causing data races}}
+  // expected-note @-1 {{sending main actor-isolated 'k' into async let risks causing data races between nonisolated and main actor-isolated uses}}
+  _ = await value2
+}
+
+@MainActor
+func testUnrolledLoopWithAsyncLet3(_ a: MainActorKlass) async {
+  let k = NonSendableKlass()
+  await unspecifiedAsyncUse(k)
+  // This is valid since our valid is disconnected here.
+  async let value: () = await unspecifiedAsyncUse(k)
+  _ = await value
+
+  await a.useValueAsync(k)
+  async let value2: () = await sendToMain(k) // expected-error {{sending 'k' risks causing data races}}
+  // expected-note @-1 {{sending main actor-isolated 'k' into async let risks causing data races between nonisolated and main actor-isolated uses}}
+  _ = await value2
+}
+
+func unspecifiedCallingVariousNonisolated(_ x: NonSendableKlass) async {
+  await x.unspecifiedCaller()
+  await x.nonisolatedCaller()
+  await x.nonisolatedNonSendingCaller()
+  await x.concurrentCaller() // expected-enabled-error {{sending 'x' risks causing data races}}
+  // expected-enabled-note @-1 {{sending task-isolated 'x' to @concurrent instance method 'concurrentCaller()' risks causing data races between @concurrent and task-isolated uses}}
+
+  await unspecifiedAsyncUse(x)
+  await nonisolatedAsyncUse(x)
+  await nonisolatedNonSendingAsyncUse(x)
+  await concurrentAsyncUse(x) // expected-enabled-error {{sending 'x' risks causing data races}}
+  // expected-enabled-note @-1 {{sending task-isolated 'x' to @concurrent global function 'concurrentAsyncUse' risks causing data races between @concurrent and task-isolated uses}}
+}
+
+nonisolated func nonisolatedCallingVariousNonisolated(_ x: NonSendableKlass) async {
+  await x.unspecifiedCaller()
+  await x.nonisolatedCaller()
+  await x.nonisolatedNonSendingCaller()
+  await x.concurrentCaller() // expected-enabled-error {{sending 'x' risks causing data races}}
+  // expected-enabled-note @-1 {{sending task-isolated 'x' to @concurrent instance method 'concurrentCaller()' risks causing data races between @concurrent and task-isolated uses}}
+
+  await unspecifiedAsyncUse(x)
+  await nonisolatedAsyncUse(x)
+  await nonisolatedNonSendingAsyncUse(x)
+  await concurrentAsyncUse(x) // expected-enabled-error {{sending 'x' risks causing data races}}
+  // expected-enabled-note @-1 {{sending task-isolated 'x' to @concurrent global function 'concurrentAsyncUse' risks causing data races between @concurrent and task-isolated uses}}
+}
+
+nonisolated(nonsending) func nonisolatedNonSendingCallingVariousNonisolated(_ x: NonSendableKlass) async {
+  await x.unspecifiedCaller() // expected-disabled-error {{sending 'x' risks causing data races}}
+  // expected-disabled-note @-1 {{sending nonisolated(nonsending) task-isolated 'x' to nonisolated instance method 'unspecifiedCaller()' risks causing data races between nonisolated and nonisolated(nonsending) task-isolated uses}}
+  await x.nonisolatedCaller() // expected-disabled-error {{sending 'x' risks causing data races}}
+  // expected-disabled-note @-1 {{sending nonisolated(nonsending) task-isolated 'x' to nonisolated instance method 'nonisolatedCaller()' risks causing data races between nonisolated and nonisolated(nonsending) task-isolated uses}}
+  await x.nonisolatedNonSendingCaller()
+  await x.concurrentCaller() // expected-error {{sending 'x' risks causing data races}}
+  // expected-disabled-note @-1 {{sending nonisolated(nonsending) task-isolated 'x' to nonisolated instance method 'concurrentCaller()' risks causing data races between nonisolated and nonisolated(nonsending) task-isolated uses}}
+  // expected-enabled-note @-2 {{sending task-isolated 'x' to @concurrent instance method 'concurrentCaller()' risks causing data races between @concurrent and task-isolated uses}}
+
+  await unspecifiedAsyncUse(x) // expected-disabled-error {{sending 'x' risks causing data races}}
+  // expected-disabled-note @-1 {{sending nonisolated(nonsending) task-isolated 'x' to nonisolated global function 'unspecifiedAsyncUse' risks causing data races between nonisolated and nonisolated(nonsending) task-isolated uses}}
+  await nonisolatedAsyncUse(x) // expected-disabled-error {{sending 'x' risks causing data races}}
+  // expected-disabled-note @-1 {{sending nonisolated(nonsending) task-isolated 'x' to nonisolated global function 'nonisolatedAsyncUse' risks causing data races between nonisolated and nonisolated(nonsending) task-isolated uses}}
+  await nonisolatedNonSendingAsyncUse(x)
+  await concurrentAsyncUse(x) // expected-error {{sending 'x' risks causing data races}}
+  // expected-disabled-note @-1 {{sending nonisolated(nonsending) task-isolated 'x' to nonisolated global function 'concurrentAsyncUse' risks causing data races between nonisolated and nonisolated(nonsending) task-isolated uses}}
+  // expected-enabled-note @-2 {{sending task-isolated 'x' to @concurrent global function 'concurrentAsyncUse' risks causing data races between @concurrent and task-isolated uses}}
+}
+
+@concurrent func concurrentCallingVariousNonisolated(_ x: NonSendableKlass) async {
+  await x.unspecifiedCaller()
+  await x.nonisolatedCaller()
+  await x.nonisolatedNonSendingCaller()
+  await x.concurrentCaller()
+
+  await unspecifiedAsyncUse(x)
+  await nonisolatedAsyncUse(x)
+  await nonisolatedNonSendingAsyncUse(x)
+  await concurrentAsyncUse(x)
+}
diff --git a/test/Concurrency/nonisolated_inherits_isolation_sema.swift b/test/Concurrency/nonisolated_inherits_isolation_sema.swift
index 24dbfceea8d56..9e1734f83e20b 100644
--- a/test/Concurrency/nonisolated_inherits_isolation_sema.swift
+++ b/test/Concurrency/nonisolated_inherits_isolation_sema.swift
@@ -1,8 +1,8 @@
-// RUN: %target-typecheck-verify-swift -swift-version 6 -enable-experimental-feature AsyncCallerExecution -parse-as-library
+// RUN: %target-typecheck-verify-swift -swift-version 6 -enable-upcoming-feature NonisolatedNonsendingByDefault -parse-as-library
 
 // REQUIRES: asserts
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_AsyncCallerExecution
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 class NonSendable {} // expected-note {{}}
 
@@ -19,7 +19,7 @@ struct MainActorIsolatedStruct {
 struct NonisolatedStruct {
   // Validate we can still not access global state.
   func asyncMethod() async {
-    let _ = await global // expected-error {{non-sendable type 'NonSendable' of var 'global' cannot exit main actor-isolated context}}
+    let _ = await global // expected-error {{non-Sendable type 'NonSendable' of var 'global' cannot exit main actor-isolated context}}
 
     let x = await MainActorIsolatedStruct()
     await x.syncMethod()
diff --git a/test/Concurrency/nonisolated_nonsending.swift b/test/Concurrency/nonisolated_nonsending.swift
new file mode 100644
index 0000000000000..869349eead497
--- /dev/null
+++ b/test/Concurrency/nonisolated_nonsending.swift
@@ -0,0 +1,64 @@
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -swift-version 6 -enable-upcoming-feature NonisolatedNonsendingByDefault %s | %FileCheck %s
+
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+protocol P: Sendable {
+  func f() async
+}
+
+// Our map closure (abstracted as returning T) returns a function
+// value, which requires it to be reabstracted to the most general
+// abstraction pattern, i.e. from
+//     nonisolated(nonsending) () async -> ()
+// to
+//     nonisolated(nonsending) () async -> U, where U == ()
+// Note that we preserve nonisolated(nonsending).
+//
+// The thunk code did not expect the output function type to be
+// nonisolated(nonsending), so it didn't handle and propagate the
+// implicit isolation argument correctly.
+func testPartialApplication(p: [any P]) async {
+  _ = p.map { $0.f }
+}
+// CHECK-LABEL: sil private @$s22nonisolated_nonsending22testPartialApplication1pySayAA1P_pG_tYaFyyYaYbYCcAaD_pXEfU_ :
+// CHECK: function_ref @$sScA_pSgIeghHgIL_AAytIeghHgILr_TR :
+
+//   Reabstraction thunk from caller-isolated () -> () to caller-isolated () -> T
+// CHECK-LABEL: sil shared [transparent] [reabstraction_thunk] @$sScA_pSgIeghHgIL_AAytIeghHgILr_TR :
+// CHECK:       bb0(%0 : $*(), %1 : $Optional<any Actor>, %2 : $@Sendable @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()):
+// CHECK-NEXT:    apply %2(%1) :
+
+func takesGenericAsyncFunction<T>(_ fn: nonisolated(nonsending) (T) async -> Void) {}
+
+// This is a more direct test of the partial-application code above.
+// Note that we have to make the functions explicitly nonisolated(nonsending)
+// because NonisolatedNonsendingByDefault only applies to declarations,
+// not function types in the abstract.
+func testReabstractionPreservingCallerIsolation(fn: nonisolated(nonsending) (Int) async -> Void) {
+  takesGenericAsyncFunction(fn)
+}
+// CHECK-LABEL: sil hidden @$s22nonisolated_nonsending42testReabstractionPreservingCallerIsolation2fnyySiYaYCXE_tF :
+// CHECK:       bb0(%0 : $@noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, Int) -> ()):
+// CHECK:         [[THUNK:%.*]] = function_ref @$sScA_pSgSiIgHgILy_AASiIegHgILn_TR :
+
+// CHECK-LABEL: sil shared [transparent] [reabstraction_thunk] @$sScA_pSgSiIgHgILy_AASiIegHgILn_TR :
+// CHECK:       bb0(%0 : $Optional<any Actor>, %1 : $*Int, %2 : $@noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, Int) -> ()):
+// CHECK-NEXT:    %3 = load %1
+// CHECK-NEXT:    apply %2(%0, %3)
+
+func takesAsyncIsolatedAnyFunction(_ fn: @isolated(any) () async -> Void) {}
+func takesGenericAsyncIsolatedAnyFunction<T>(_ fn: @isolated(any) (T) async -> Void) {}
+
+// These would be good to test, but we apparently reject this conversion.
+#if false
+
+// The same bug, but converting to an @isolated(any) function type.
+func testConversionToIsolatedAny(fn: nonisolated(nonsending) () async -> Void) {
+  takesAsyncIsolatedAnyFunction(fn)
+}
+
+func testReabstractionToIsolatedAny(fn: nonisolated(nonsending) (Int) async -> Void) {
+  takesGenericAsyncIsolatedAnyFunction(fn)
+}
+
+#endif
diff --git a/test/Concurrency/nonisolated_nonsending_objc_async_by_default.swift b/test/Concurrency/nonisolated_nonsending_objc_async_by_default.swift
new file mode 100644
index 0000000000000..f506d8141f6dd
--- /dev/null
+++ b/test/Concurrency/nonisolated_nonsending_objc_async_by_default.swift
@@ -0,0 +1,56 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck %t/src/main.swift \
+// RUN:   -import-objc-header %t/src/Test.h \
+// RUN:   -swift-version 6 \
+// RUN:   -module-name main -I %t -verify
+
+// REQUIRES: objc_interop
+
+//--- Test.h
+#define MAIN_ACTOR __attribute__((__swift_attr__("@MainActor")))
+
+#pragma clang assume_nonnull begin
+
+@import Foundation;
+
+@interface Test : NSObject
+- (void)loadWithCompletionHandler:(void (^)(void)) completionHandler;
+@end
+
+MAIN_ACTOR
+@interface TestIsolated : NSObject
+- (void)loadWithCompletionHandler:(void (^)(void)) completionHandler;
+@end
+
+#pragma clang assume_nonnull end
+
+//--- main.swift
+
+class OverrideTest1 : Test {
+  override func load() async {}
+}
+
+class OverrideTest2 : TestIsolated {
+  override func load() async {}
+}
+
+func test(t: Test, i: TestIsolated) async throws {
+  let fn = t.load // nonisolated(nonsending) () async -> Void
+
+  let _: @isolated(any) () async -> Void = fn
+  // expected-error@-1 {{cannot convert value of type 'nonisolated(nonsending) () async -> Void' to specified type '@isolated(any) () async -> Void'}}
+
+  let isolatedFn = i.load
+  let _: () -> Void = isolatedFn
+  // expected-error@-1 {{invalid conversion from 'async' function of type '@MainActor @Sendable () async -> Void' to synchronous function type '() -> Void'}}
+}
+
+func testOverrides(o1: OverrideTest1, o2: OverrideTest2) {
+  let _: () -> Void = o1.load
+  // expected-error@-1 {{invalid conversion from 'async' function of type '() async -> ()' to synchronous function type '() -> Void'}}
+  let _: () -> Void = o2.load
+  // expected-error@-1 {{invalid conversion from 'async' function of type '@MainActor @Sendable () async -> ()' to synchronous function type '() -> Void'}}
+}
diff --git a/test/Concurrency/nonisolated_nonsending_optimize_hoptoexecutor.swift b/test/Concurrency/nonisolated_nonsending_optimize_hoptoexecutor.swift
new file mode 100644
index 0000000000000..83e001e3e8774
--- /dev/null
+++ b/test/Concurrency/nonisolated_nonsending_optimize_hoptoexecutor.swift
@@ -0,0 +1,30 @@
+// RUN: %target-swift-frontend -module-name test -swift-version 6 -emit-sil %s | %FileCheck --implicit-check-not=hop_to_executor  %s
+
+// REQUIRES: concurrency
+
+// CHECK-LABEL: sil hidden [noinline] @$s4testAAyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// CHECK: } // end sil function '$s4testAAyyYaF'
+@inline(never)
+nonisolated(nonsending) func test() async {}
+
+// CHECK-LABEL: sil hidden [noinline] @$s4test5test2yyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// CHECK: } // end sil function '$s4test5test2yyYaF'
+@inline(never)
+nonisolated(nonsending) func test2() async {
+  await test()
+}
+
+@inline(never)
+func test3() async {
+}
+
+// CHECK-LABEL: sil @$s4test6calleryyYaF : $@convention(thin) @async () -> () {
+// CHECK: hop_to_executor
+// CHECK: function_ref @$s4testAAyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+// CHECK: function_ref @$s4test5test2yyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+// CHECK: } // end sil function '$s4test6calleryyYaF'
+public func caller() async {
+  await test()
+  await test2()
+  await test3()
+}
diff --git a/test/Concurrency/nonisolated_rules.swift b/test/Concurrency/nonisolated_rules.swift
index 669f876a81db6..118d060237efc 100644
--- a/test/Concurrency/nonisolated_rules.swift
+++ b/test/Concurrency/nonisolated_rules.swift
@@ -5,6 +5,19 @@
 @MainActor
 protocol GloballyIsolated {}
 
+@globalActor
+actor Test {
+  static let shared: Test = Test()
+}
+
+@Test
+protocol TestIsolatedProto {
+}
+
+@Test
+protocol RedeclaredIsolationProto : GloballyIsolated {
+}
+
 // expected-note@+1 {{class 'NonSendable' does not conform to the 'Sendable' protocol}}
 class NonSendable {}
 
@@ -23,8 +36,8 @@ struct ImplicitlySendable {
   nonisolated var d = 0
 
   // never okay
-  nonisolated lazy var e = 0  // expected-error {{'nonisolated' is not supported on lazy properties}}
-  @P nonisolated var f = 0  // expected-error {{'nonisolated' is not supported on properties with property wrappers}}
+  nonisolated lazy var e = 0 // expected-error {{'nonisolated' cannot be applied to mutable stored properties}}
+  @P nonisolated var f = 0  // expected-error {{'nonisolated' cannot be applied to mutable stored properties}}
 }
 
 struct ImplicitlyNonSendable {
@@ -35,9 +48,9 @@ struct ImplicitlyNonSendable {
   nonisolated var c: Int { 0 }
   nonisolated var d = 0
 
-  // never okay
-  nonisolated lazy var e = 0  // expected-error {{'nonisolated' is not supported on lazy properties}}
-  @P nonisolated var f = 0  // expected-error {{'nonisolated' is not supported on properties with property wrappers}}
+  // okay, the type is non-'Sendable'
+  nonisolated lazy var e = 0
+  @P nonisolated var f = 0
 }
 
 public struct PublicSendable: Sendable {
@@ -47,8 +60,8 @@ public struct PublicSendable: Sendable {
   nonisolated var d = 0
 
   // never okay
-  nonisolated lazy var e = 0  // expected-error {{'nonisolated' is not supported on lazy properties}}
-  @P nonisolated var f = 0  // expected-error {{'nonisolated' is not supported on properties with property wrappers}}
+  nonisolated lazy var e = 0  // expected-error {{'nonisolated' cannot be applied to mutable stored properties}}
+  @P nonisolated var f = 0  // expected-error {{'nonisolated' cannot be applied to mutable stored properties}}
 }
 
 public struct PublicNonSendable {
@@ -57,13 +70,13 @@ public struct PublicNonSendable {
   nonisolated var c: Int { 0 }
   nonisolated var d = 0
 
-  // never okay
-  nonisolated lazy var e = 0  // expected-error {{'nonisolated' is not supported on lazy properties}}
-  @P nonisolated var f = 0  // expected-error {{'nonisolated' is not supported on properties with property wrappers}}
+  // okay, the type is non-'Sendable'
+  nonisolated lazy var e = 0
+  @P nonisolated var f = 0
 }
 
 
-nonisolated struct NonisolatedStruct: GloballyIsolated {
+nonisolated struct StructRemovesGlobalActor: GloballyIsolated {
   var x: NonSendable
   var y: Int = 1
 
@@ -83,6 +96,8 @@ nonisolated struct NonisolatedStruct: GloballyIsolated {
 
 @MainActor struct S {
   var value: NonSendable // globally-isolated
+  @P nonisolated var x = 0 // expected-error {{'nonisolated' cannot be applied to mutable stored properties}}
+  nonisolated lazy var y = 1 // expected-error {{'nonisolated' cannot be applied to mutable stored properties}}
   struct Nested {} // 'Nested' is not @MainActor-isolated
 }
 
@@ -91,6 +106,8 @@ nonisolated struct NonisolatedStruct: GloballyIsolated {
 
 nonisolated struct S1: GloballyIsolated {
   var x: NonSendable
+  @P nonisolated var y = 0 // okay
+  nonisolated lazy var z = 1 // okay
   func f() {
     // expected-error@+1 {{call to main actor-isolated global function 'requireMain()' in a synchronous nonisolated context}}
     requireMain()
@@ -100,12 +117,110 @@ nonisolated struct S1: GloballyIsolated {
 // MARK: - Protocols
 
 nonisolated protocol Refined: GloballyIsolated {}
+nonisolated protocol WhyNot {}
+
+nonisolated protocol NonisolatedWithMembers {
+  func test()
+}
 
 struct A: Refined {
   var x: NonSendable
   init(x: NonSendable) {
     self.x = x // okay
   }
+
+  init() {
+    self.x = NonSendable()
+  }
+
+  func f() {}
+}
+
+@MainActor protocol ExplicitGlobalActor: Refined {}
+
+struct IsolatedA: ExplicitGlobalActor {
+  // expected-note@+2 {{main actor isolation inferred from conformance to protocol 'ExplicitGlobalActor'}}
+  // expected-note@+1 {{calls to instance method 'g()' from outside of its actor context are implicitly asynchronous}}
+  func g() {}
+}
+
+struct IsolatedB: Refined, ExplicitGlobalActor {
+  // expected-note@+2 {{calls to instance method 'h()' from outside of its actor context are implicitly asynchronous}}
+  // expected-note@+1 {{main actor isolation inferred from conformance to protocol 'ExplicitGlobalActor'}}
+  func h() {}
+}
+
+struct IsolatedC: WhyNot, GloballyIsolated {
+  // expected-note@+2 {{calls to instance method 'k()' from outside of its actor context are implicitly asynchronous}}
+  // expected-note@+1 {{main actor isolation inferred from conformance to protocol 'GloballyIsolated'}}
+  func k() {}
+}
+
+struct IsolatedCFlipped: GloballyIsolated, WhyNot {
+  // expected-note@+2 {{calls to instance method 'k2()' from outside of its actor context are implicitly asynchronous}}
+  // expected-note@+1 {{main actor isolation inferred from conformance to protocol 'GloballyIsolated'}}
+  func k2() {}
+}
+
+struct NonisolatedStruct {
+  func callF() {
+    return A().f() // okay, 'A' is non-isolated.
+  }
+
+  // expected-note@+1 {{add '@MainActor' to make instance method 'callG()' part of global actor 'MainActor'}}
+  func callG() {
+    // expected-error@+1{{call to main actor-isolated instance method 'g()' in a synchronous nonisolated context}}
+    return IsolatedA().g()
+  }
+
+  // expected-note@+1 {{add '@MainActor' to make instance method 'callH()' part of global actor 'MainActor'}}
+  func callH() {
+    // expected-error@+1 {{call to main actor-isolated instance method 'h()' in a synchronous nonisolated context}}
+    return IsolatedB().h()
+  }
+
+  // expected-note@+1 {{add '@MainActor' to make instance method 'callK()' part of global actor 'MainActor'}}
+  func callK() {
+    // expected-error@+1 {{call to main actor-isolated instance method 'k()' in a synchronous nonisolated context}}
+    return IsolatedC().k()
+  }
+
+  // expected-note@+1 {{add '@MainActor' to make instance method 'callK2()' part of global actor 'MainActor'}}
+  func callK2() {
+    // expected-error@+1 {{call to main actor-isolated instance method 'k2()' in a synchronous nonisolated context}}
+    return IsolatedCFlipped().k2()
+  }
+}
+
+@MainActor
+struct TestIsolated : NonisolatedWithMembers {
+  var x: NonSendable // expected-note {{property declared here}}
+
+  // requirement behaves as if it's explicitly `nonisolated` which gets inferred onto the witness
+  func test() {
+    _ = x // expected-error {{main actor-isolated property 'x' can not be referenced from a nonisolated context}}
+  }
+}
+
+@MainActor
+protocol Root {
+  func testRoot()
+}
+
+nonisolated protocol Child : Root {
+  func testChild()
+}
+
+struct TestDifferentLevels : Child {
+  func testRoot() {}
+  func testChild() {}
+  func testNonWitness() {}
+}
+
+nonisolated func testRequirementsOnMultipleNestingLevels(t: TestDifferentLevels) {
+  t.testRoot() // okay
+  t.testChild() // okay
+  t.testNonWitness() // okay
 }
 
 // MARK: - Extensions
@@ -144,6 +259,34 @@ nonisolated class K: GloballyIsolated {
   }
 }
 
+@MainActor
+protocol GloballyIsolatedWithRequirements {
+  var x: NonSendable { get set } // expected-note {{property declared here}}
+  func test() // expected-note {{calls to instance method 'test()' from outside of its actor context are implicitly asynchronous}}
+}
+
+nonisolated class K2: GloballyIsolatedWithRequirements {
+  var x: NonSendable
+
+  func test() {}
+
+  func testNonWitness() {}
+
+  init(x: NonSendable) {
+    self.x = x // okay
+    test() // okay
+    testNonWitness() // okay
+  }
+
+  func test<T: GloballyIsolatedWithRequirements>(t: T, s: K2) {
+    _ = s.x // okay
+    _ = t.x // expected-error {{main actor-isolated property 'x' can not be referenced from a nonisolated context}}
+
+    s.test() // okay
+    t.test() // expected-error {{call to main actor-isolated instance method 'test()' in a synchronous nonisolated context}}
+  }
+}
+
 // MARK: - Storage of non-Sendable
 
 class KlassA {
@@ -186,3 +329,25 @@ func rdar147965036() {
     // expected-error@-2 {{'nonisolated' is not supported on a closure}}
   }
 }
+
+// Test that clash in isolation from protocols results in nonisolated conforming type
+func testProtocolIsolationClash() {
+  struct A: GloballyIsolated, TestIsolatedProto {
+  }
+
+  struct B: RedeclaredIsolationProto {
+  }
+
+  struct C: GloballyIsolated, TestIsolatedProto, WhyNot {
+  }
+
+  struct D: WhyNot, GloballyIsolated, TestIsolatedProto {
+  }
+
+  nonisolated func test() {
+    _ = A() // Ok
+    _ = B() // Ok
+    _ = C() // Ok
+    _ = D() // Ok
+  }
+}
diff --git a/test/Concurrency/objc_async_overload.swift b/test/Concurrency/objc_async_overload.swift
index 78a99a7a42e37..f60f39e1eb247 100644
--- a/test/Concurrency/objc_async_overload.swift
+++ b/test/Concurrency/objc_async_overload.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk)  -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -import-objc-header %S/Inputs/Delegate.h -enable-experimental-feature SendableCompletionHandlers %s
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk)  -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -import-objc-header %S/Inputs/Delegate.h -enable-experimental-feature SendableCompletionHandlers %s -strict-concurrency=targeted
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk)  -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -import-objc-header %S/Inputs/Delegate.h -enable-experimental-feature SendableCompletionHandlers %s -strict-concurrency=complete
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk)  -target %target-swift-5.1-abi-triple -emit-sil -o /dev/null -verify -import-objc-header %S/Inputs/Delegate.h -enable-experimental-feature SendableCompletionHandlers %s -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
 // REQUIRES: objc_interop
-// REQUIRES: swift_feature_RegionBasedIsolation
 // REQUIRES: swift_feature_SendableCompletionHandlers
 
 // overload resolution should pick sync version in a sync context
@@ -43,10 +41,10 @@ func asyncWithAwait() async {
 // completion handler's implicit `@Sendable` isn't respected.
 extension Delegate {
   nonisolated func makeRequest(_ req: Request??, completionHandler: (() -> Void)? = nil) {
-    // expected-note@-1 {{parameter 'completionHandler' is implicitly non-sendable}}
+    // expected-note@-1 {{parameter 'completionHandler' is implicitly non-Sendable}}
     if let req = (req ?? nil) {
       makeRequest1(req, completionHandler: completionHandler)
-      // expected-warning@-1 {{passing non-sendable parameter 'completionHandler' to function expecting a @Sendable closure}}
+      // expected-warning@-1 {{passing non-Sendable parameter 'completionHandler' to function expecting a '@Sendable' closure}}
     }
   }
 }
@@ -58,7 +56,7 @@ extension Delegate {
   func handle(_ req: Request, with delegate: Delegate) {
     delegate.makeRequest1(req) {
       self.finish()
-      // expected-warning@-1 {{call to main actor-isolated instance method 'finish()' in a synchronous nonisolated context; this is an error in the Swift 6 language mode}}
+      // expected-warning@-1 {{call to main actor-isolated instance method 'finish()' in a synchronous nonisolated context}}
     }
   }
 }
diff --git a/test/Concurrency/objc_require_explicit_sendable.swift b/test/Concurrency/objc_require_explicit_sendable.swift
index 9997e00b6de93..e0a47aac9d339 100644
--- a/test/Concurrency/objc_require_explicit_sendable.swift
+++ b/test/Concurrency/objc_require_explicit_sendable.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -o /dev/null -I %S/Inputs/custom-modules %s -verify -parse-as-library -require-explicit-sendable
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -o /dev/null -I %S/Inputs/custom-modules %s -verify -parse-as-library -require-explicit-sendable -strict-concurrency=targeted
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -o /dev/null -I %S/Inputs/custom-modules %s -verify -parse-as-library -require-explicit-sendable -strict-concurrency=complete
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil -o /dev/null -I %S/Inputs/custom-modules %s -verify -parse-as-library -require-explicit-sendable -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: objc_interop
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 import Foundation
 import ObjCConcurrency
@@ -15,5 +13,4 @@ open class Y: X { }
 
 
 open class Z: NSObject { } // expected-warning{{public class 'Z' does not specify whether it is 'Sendable' or not}}
-// expected-note@-1{{add '@unchecked Sendable' conformance to class 'Z' if this type manually implements concurrency safety}}
-// expected-note@-2{{make class 'Z' explicitly non-Sendable to suppress this warning}}
+// expected-note@-1{{make class 'Z' explicitly non-Sendable to suppress this warning}}
diff --git a/test/Concurrency/optional_isolated_parameters.swift b/test/Concurrency/optional_isolated_parameters.swift
index 048c8cb9ab82f..a631ab0a20022 100644
--- a/test/Concurrency/optional_isolated_parameters.swift
+++ b/test/Concurrency/optional_isolated_parameters.swift
@@ -5,6 +5,7 @@
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
+// REQUIRES: concurrency_runtime
 
 // rdar://124277662
 // XFAIL: freestanding
diff --git a/test/Concurrency/preconcurrency_conformances.swift b/test/Concurrency/preconcurrency_conformances.swift
index 55ea098bd92b5..c1a18aaff3800 100644
--- a/test/Concurrency/preconcurrency_conformances.swift
+++ b/test/Concurrency/preconcurrency_conformances.swift
@@ -10,28 +10,28 @@ do {
   class K {}
 
   struct A : @preconcurrency Q {} // Ok
-  // expected-warning@-1 {{@preconcurrency attribute on conformance to 'Q' has no effect}}
+  // expected-warning@-1 {{'@preconcurrency' on conformance to 'Q' has no effect}}
 
   struct B : @preconcurrency K {
-    // expected-error@-1 {{'preconcurrency' attribute cannot apply to non-protocol type 'K'}}
+    // expected-error@-1 {{'@preconcurrency' cannot apply to non-protocol type 'K'}}
     var x: @preconcurrency Int
-    // expected-error@-1 {{'preconcurrency' attribute only applies in inheritance clauses}}
+    // expected-error@-1 {{'@preconcurrency' only applies in inheritance clauses}}
   }
 
   typealias T = @preconcurrency Q
-  // expected-error@-1 {{'preconcurrency' attribute only applies in inheritance clauses}}
+  // expected-error@-1 {{'@preconcurrency' only applies in inheritance clauses}}
 
   func test(_: @preconcurrency K) {}
-  // expected-error@-1 {{'preconcurrency' attribute only applies in inheritance clauses}}
+  // expected-error@-1 {{'@preconcurrency' only applies in inheritance clauses}}
 }
 
 protocol InvalidUseOfPreconcurrencyAttr : @preconcurrency Q {
-  // expected-error@-1 {{'preconcurrency' attribute only applies in inheritance clauses}}
+  // expected-error@-1 {{'@preconcurrency' only applies in inheritance clauses}}
 }
 
 struct TestPreconcurrencyAttr {}
 extension TestPreconcurrencyAttr : @preconcurrency Q { // Ok
-  // expected-warning@-1 {{@preconcurrency attribute on conformance to 'Q' has no effect}}
+  // expected-warning@-1 {{'@preconcurrency' on conformance to 'Q' has no effect}}
 }
 
 class NonSendable {}
@@ -99,7 +99,7 @@ protocol Initializable {
 }
 
 final class K : @preconcurrency Initializable {
-  // expected-warning@-1 {{@preconcurrency attribute on conformance to 'Initializable' has no effect}}
+  // expected-warning@-1 {{'@preconcurrency' on conformance to 'Initializable' has no effect}}
   init() {} // Ok
 }
 
@@ -108,6 +108,7 @@ final class K : @preconcurrency Initializable {
 final class MainActorK: Initializable {
   // expected-note@-1{{turn data races into runtime errors with '@preconcurrency'}}{{25-25=@preconcurrency }}
   // expected-note@-2{{mark all declarations used in the conformance 'nonisolated'}}
+  // expected-note@-3{{isolate this conformance to the main actor with '@MainActor'}}
   init() { } // expected-note{{main actor-isolated initializer 'init()' cannot satisfy nonisolated requirement}}
 }
 
@@ -138,7 +139,7 @@ do {
   // expected-warning@+2{{conformance of 'TestExplicitGlobalActorAttrs' to protocol 'WithIndividuallyIsolatedRequirements' involves isolation mismatches and can cause data races}}
   @MainActor
   struct TestExplicitGlobalActorAttrs : @preconcurrency WithIndividuallyIsolatedRequirements {
-    // expected-warning@-1 {{@preconcurrency attribute on conformance to 'WithIndividuallyIsolatedRequirements' has no effect}}
+    // expected-warning@-1 {{'@preconcurrency' on conformance to 'WithIndividuallyIsolatedRequirements' has no effect}}
 
     var a: Int = 42
 
@@ -163,7 +164,7 @@ protocol WithNonIsolated {
 do {
   // expected-warning@+1{{conformance of 'TestExplicitOtherIsolation' to protocol 'WithNonIsolated' involves isolation mismatches and can cause data races}}
   class TestExplicitOtherIsolation : @preconcurrency WithNonIsolated {
-    // expected-warning@-1 {{@preconcurrency attribute on conformance to 'WithNonIsolated' has no effect}}{{38-54=}}
+    // expected-warning@-1 {{'@preconcurrency' on conformance to 'WithNonIsolated' has no effect}}{{38-54=}}
 
     @GlobalActor var prop: Int = 42
     // expected-note@-1 {{global actor 'GlobalActor'-isolated property 'prop' cannot satisfy main actor-isolated requirement}}
@@ -175,7 +176,7 @@ do {
 
 do {
   class InferredGlobalActorAttrs : @preconcurrency WithNonIsolated {
-    // expected-warning@-1 {{@preconcurrency attribute on conformance to 'WithNonIsolated' has no effect}}{{36-52=}}
+    // expected-warning@-1 {{'@preconcurrency' on conformance to 'WithNonIsolated' has no effect}}{{36-52=}}
     var prop: Int = 42
     func test() {}
   }
@@ -202,7 +203,7 @@ do {
   protocol P2 {}
   protocol P3: P1, P2 {}
 
-  // expected-warning@+1 {{@preconcurrency attribute on conformance to 'P3' has no effect}}
+  // expected-warning@+1 {{'@preconcurrency' on conformance to 'P3' has no effect}}
   @MainActor struct S: @preconcurrency P3 {}
 }
 
@@ -233,21 +234,23 @@ do {
   // preconcurrency has no effect here.
   // expected-warning@+1{{conformance of 'S4' to protocol 'P2' crosses into main actor-isolated code and can cause data races}}
   @MainActor struct S4: @preconcurrency P3, P2 {
-    // expected-warning@-1:21 {{@preconcurrency attribute on conformance to 'P3' has no effect}}
+    // expected-warning@-1:21 {{'@preconcurrency' on conformance to 'P3' has no effect}}
     // expected-note@-2:45 {{turn data races into runtime errors with '@preconcurrency'}}
     // expected-note@-3{{mark all declarations used in the conformance 'nonisolated'}}
+    // expected-note@-4{{isolate this conformance to the main actor with '@MainActor'}}
     func foo() {}
     // expected-note@-1 {{main actor-isolated instance method 'foo()' cannot satisfy nonisolated requirement}}
   }
   // expected-warning@+1{{conformance of 'S5' to protocol 'P2' crosses into main actor-isolated code and can cause data races; this is an error in the Swift 6 language mode}}
   @MainActor struct S5: P2, @preconcurrency P3 {
-    // expected-warning@-1:21 {{@preconcurrency attribute on conformance to 'P3' has no effect}}
+    // expected-warning@-1:21 {{'@preconcurrency' on conformance to 'P3' has no effect}}
     // expected-note@-2:25 {{turn data races into runtime errors with '@preconcurrency'}}
     // expected-note@-3{{mark all declarations used in the conformance 'nonisolated'}}
+    // expected-note@-4{{isolate this conformance to the main actor with '@MainActor'}}
     func foo() {}
     // expected-note@-1 {{main actor-isolated instance method 'foo()' cannot satisfy nonisolated requirement}}
   }
-  // expected-warning@+1 {{@preconcurrency attribute on conformance to 'P3' has no effect}}
+  // expected-warning@+1 {{'@preconcurrency' on conformance to 'P3' has no effect}}
   @MainActor struct S6: @preconcurrency P2, @preconcurrency P3 {
     func foo() {}
   }
@@ -271,7 +274,7 @@ do {
 
   // Preconcurrency effectful for 'P3' only.
   @MainActor struct S3: @preconcurrency P3 & P4 {
-  // expected-warning@-1:21 {{@preconcurrency attribute on conformance to 'P4' has no effect}}
+  // expected-warning@-1:21 {{'@preconcurrency' on conformance to 'P4' has no effect}}
     func foo() {}
   }
 }
@@ -301,9 +304,10 @@ do {
 
   // expected-warning@+1{{conformance of 'S4' to protocol 'P2' crosses into main actor-isolated code and can cause data races}}
   @MainActor struct S4: P6, @preconcurrency P5 {
-    // expected-warning@-1:21 {{@preconcurrency attribute on conformance to 'P5' has no effect}}
+    // expected-warning@-1:21 {{'@preconcurrency' on conformance to 'P5' has no effect}}
     // expected-note@-2{{turn data races into runtime errors with '@preconcurrency'}}
     // expected-note@-3{{mark all declarations used in the conformance 'nonisolated'}}
+    // expected-note@-4{{isolate this conformance to the main actor with '@MainActor'}}
     func foo() {}
     // expected-note@-1 {{main actor-isolated instance method 'foo()' cannot satisfy nonisolated requirement}}
   }
diff --git a/test/Concurrency/preconcurrency_implementationonly_override.swift b/test/Concurrency/preconcurrency_implementationonly_override.swift
index 4bc3b24b25653..414dbc3ad3684 100644
--- a/test/Concurrency/preconcurrency_implementationonly_override.swift
+++ b/test/Concurrency/preconcurrency_implementationonly_override.swift
@@ -2,13 +2,11 @@
 
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/ImplementationOnlyDefs.swiftmodule -module-name ImplementationOnlyDefs %S/Inputs/ImplementationOnlyDefs.swift \
 // RUN:   -enable-library-evolution -swift-version 5
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -I %t -enable-library-evolution -swift-version 5 -emit-sil -o /dev/null -verify %s
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -I %t -enable-library-evolution -swift-version 5 -emit-sil -o /dev/null -verify -strict-concurrency=targeted %s
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -I %t -enable-library-evolution -swift-version 5 -emit-sil -o /dev/null -verify -strict-concurrency=complete %s
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -I %t -enable-library-evolution -swift-version 5 -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation %s
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -I %t -enable-library-evolution -swift-version 5 -emit-sil -o /dev/null -verify -verify-ignore-unrelated %s
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -I %t -enable-library-evolution -swift-version 5 -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=targeted %s
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -I %t -enable-library-evolution -swift-version 5 -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=complete %s
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @_implementationOnly import ImplementationOnlyDefs
 // expected-warning @-1 {{'@_implementationOnly' is deprecated, use 'internal import' instead}}
diff --git a/test/Concurrency/preconcurrency_overload.swift b/test/Concurrency/preconcurrency_overload.swift
index e2c5c13c7153a..4b1ecfe980975 100644
--- a/test/Concurrency/preconcurrency_overload.swift
+++ b/test/Concurrency/preconcurrency_overload.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s
 // RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=targeted
-// RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -verify-additional-prefix complete-and-tns- -strict-concurrency=complete
-// RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -verify-additional-prefix complete-and-tns- -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
+// RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -verify-additional-prefix complete- -strict-concurrency=complete
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // https://github.com/apple/swift/issues/59909
 struct Future<T> { }
@@ -24,15 +22,15 @@ extension Future {
 extension Future {
   @available(*, deprecated, message: "")
   func flatMap<NewValue>(file: StaticString = #file, line: UInt = #line, _ callback: @escaping (T) -> Future<NewValue>) -> Future<NewValue> { // #2
-    // expected-complete-and-tns-note @-1 {{parameter 'callback' is implicitly non-sendable}}
+    // expected-complete-note @-1 {{parameter 'callback' is implicitly non-Sendable}}
     return self.flatMap(callback)
-    // expected-complete-and-tns-warning @-1 {{passing non-sendable parameter 'callback' to function expecting a @Sendable closure}}
+    // expected-complete-warning @-1 {{passing non-Sendable parameter 'callback' to function expecting a '@Sendable' closure}}
   }
 
   @inlinable
   @available(*, deprecated, message: "Please don't pass file:line:, there's no point.")
   public func flatMapErrorThrowing(file: StaticString = #file, line: UInt = #line, _ callback: @escaping (Error) throws -> T) -> Future<T> {
     return self.flatMapErrorThrowing(callback)
-    // expected-complete-and-tns-warning @-1 {{function call causes an infinite recursion}}
+    // expected-complete-warning @-1 {{function call causes an infinite recursion}}
   }
 }
diff --git a/test/Concurrency/preconcurrency_typealias.swift b/test/Concurrency/preconcurrency_typealias.swift
index 85b44e404c819..2f7286be3fa95 100644
--- a/test/Concurrency/preconcurrency_typealias.swift
+++ b/test/Concurrency/preconcurrency_typealias.swift
@@ -1,12 +1,12 @@
 // RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=minimal
 // RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=targeted -verify-additional-prefix targeted-complete-
-// RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=complete -verify-additional-prefix targeted-complete- -verify-additional-prefix complete-tns-
+// RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=complete -verify-additional-prefix targeted-complete- -verify-additional-prefix complete-
 
 // REQUIRES: concurrency
 
 @preconcurrency @MainActor func f() { }
 // expected-note @-1 2{{calls to global function 'f()' from outside of its actor context are implicitly asynchronous}}
-// expected-complete-tns-note @-2 2{{calls to global function 'f()' from outside of its actor context are implicitly asynchronous}}
+// expected-complete-note @-2 2{{calls to global function 'f()' from outside of its actor context are implicitly asynchronous}}
 
 @preconcurrency typealias FN = @Sendable () -> Void
 
@@ -18,18 +18,18 @@ struct Outer {
 
 func test() {
   var _: Outer.FN = {
-    f() // expected-complete-tns-warning {{call to main actor-isolated global function 'f()' in a synchronous nonisolated context}}
+    f() // expected-complete-warning {{call to main actor-isolated global function 'f()' in a synchronous nonisolated context}}
   }
 
   var _: FN = {
-    f() // expected-complete-tns-warning {{call to main actor-isolated global function 'f()' in a synchronous nonisolated context}}
+    f() // expected-complete-warning {{call to main actor-isolated global function 'f()' in a synchronous nonisolated context}}
     print("Hello")
   }
 
   var mutableVariable = 0
   preconcurrencyFunc {
     mutableVariable += 1 // no sendable warning unless we have complete
-    // expected-complete-tns-warning @-1 {{mutation of captured var 'mutableVariable' in concurrently-executing code}}
+    // expected-complete-warning @-1 {{mutation of captured var 'mutableVariable' in concurrently-executing code}}
   }
   mutableVariable += 1
 }
@@ -57,10 +57,10 @@ func testAsync() async {
 @preconcurrency typealias Handler = (@Sendable () -> OtherHandler?)?
 @preconcurrency func f(arg: Int, withFn: Handler?) {}
 
-class C { // expected-complete-tns-note {{class 'C' does not conform to the 'Sendable' protocol}}
+class C { // expected-complete-note {{class 'C' does not conform to the 'Sendable' protocol}}
   func test() {
     f(arg: 5, withFn: { [weak self] () -> OtherHandler? in
-        _ = self // expected-complete-tns-warning {{capture of 'self' with non-sendable type 'C?' in a '@Sendable' closure}}
+        _ = self // expected-complete-warning {{capture of 'self' with non-Sendable type 'C?' in a '@Sendable' closure}}
         return nil
       })
   }
diff --git a/test/Concurrency/predates_concurrency.swift b/test/Concurrency/predates_concurrency.swift
index 7f3f6f734dcb5..1329cb7e45597 100644
--- a/test/Concurrency/predates_concurrency.swift
+++ b/test/Concurrency/predates_concurrency.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -verify-additional-prefix minimal-targeted-
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted -verify-additional-prefix minimal-targeted-
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -verify-additional-prefix complete-tns-
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation -verify-additional-prefix complete-tns-
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -verify-additional-prefix complete-
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @preconcurrency func unsafelySendableClosure(_ closure: @Sendable () -> Void) { }
 
@@ -27,7 +25,7 @@ struct X {
 
 @MainActor func onMainActor() { }
 
-func testInAsync(x: X, plainClosure: () -> Void) async { // expected-note 2{{parameter 'plainClosure' is implicitly non-sendable}}
+func testInAsync(x: X, plainClosure: () -> Void) async { // expected-note 2{{parameter 'plainClosure' is implicitly non-Sendable}}
   let _: Int = unsafelySendableClosure // expected-error{{type '(@Sendable () -> Void) -> ()'}}
   let _: Int = unsafelyMainActorClosure // expected-error{{type '(@MainActor () -> Void) -> ()'}}
   let _: Int = unsafelyDoEverythingClosure // expected-error{{type '(@MainActor @Sendable () -> Void) -> ()'}}
@@ -41,47 +39,47 @@ func testInAsync(x: X, plainClosure: () -> Void) async { // expected-note 2{{par
   let _: Int = x[{ onMainActor() }] // expected-error{{type '@Sendable () -> Void'}}
   let _: Int = X[statically: { onMainActor() }] // expected-error{{type '@Sendable () -> Void'}}
 
-  unsafelySendableClosure(plainClosure) // expected-warning {{passing non-sendable parameter 'plainClosure' to function expecting a @Sendable closure}}
+  unsafelySendableClosure(plainClosure) // expected-warning {{passing non-Sendable parameter 'plainClosure' to function expecting a '@Sendable' closure}}
   unsafelyMainActorClosure(plainClosure)
-  unsafelyDoEverythingClosure(plainClosure) // expected-warning {{passing non-sendable parameter 'plainClosure' to function expecting a @Sendable closure}}
+  unsafelyDoEverythingClosure(plainClosure) // expected-warning {{passing non-Sendable parameter 'plainClosure' to function expecting a '@Sendable' closure}}
 }
 
 func testElsewhere(x: X) {
   let _: Int = unsafelySendableClosure // expected-minimal-targeted-error {{type '(() -> Void) -> ()'}}
-  // expected-complete-tns-error @-1 {{type '(@Sendable () -> Void) -> ()'}}
+  // expected-complete-error @-1 {{type '(@Sendable () -> Void) -> ()'}}
   let _: Int = unsafelyMainActorClosure // expected-minimal-targeted-error {{type '(() -> Void) -> ()'}}
-  // expected-complete-tns-error @-1 {{type '(@MainActor () -> Void) -> ()'}}
+  // expected-complete-error @-1 {{type '(@MainActor () -> Void) -> ()'}}
   let _: Int = unsafelyDoEverythingClosure // expected-minimal-targeted-error {{type '(() -> Void) -> ()'}}
-  // expected-complete-tns-error @-1 {{type '(@MainActor @Sendable () -> Void) -> ()'}}
+  // expected-complete-error @-1 {{type '(@MainActor @Sendable () -> Void) -> ()'}}
   let _: Int = x.unsafelyDoEverythingClosure // expected-minimal-targeted-error{{type '(() -> Void) -> ()'}}
-  // expected-complete-tns-error @-1 {{type '(@MainActor @Sendable () -> Void) -> ()'}}
+  // expected-complete-error @-1 {{type '(@MainActor @Sendable () -> Void) -> ()'}}
   let _: Int = X.unsafelyDoEverythingClosure // expected-minimal-targeted-error{{type '(X) -> (() -> Void) -> ()'}}
-  // expected-complete-tns-error @-1 {{type '(X) -> (@MainActor @Sendable () -> Void) -> ()'}}
+  // expected-complete-error @-1 {{type '(X) -> (@MainActor @Sendable () -> Void) -> ()'}}
   let _: Int = (X.unsafelyDoEverythingClosure)(x) // expected-minimal-targeted-error{{type '(() -> Void) -> ()'}}
-  // expected-complete-tns-error @-1 {{type '(@MainActor @Sendable () -> Void) -> ()'}}
+  // expected-complete-error @-1 {{type '(@MainActor @Sendable () -> Void) -> ()'}}
   let _: Int = x.sendableVar // expected-minimal-targeted-error {{type '() -> Void'}}
-  // expected-complete-tns-error @-1 {{type '@Sendable () -> Void'}}
+  // expected-complete-error @-1 {{type '@Sendable () -> Void'}}
   let _: Int = x.mainActorVar // expected-minimal-targeted-error {{type '() -> Void'}}
-  // expected-complete-tns-error @-1 {{type '@MainActor () -> Void'}}
+  // expected-complete-error @-1 {{type '@MainActor () -> Void'}}
   let _: Int = x[{ onMainActor() }] // expected-minimal-targeted-error {{type '() -> Void'}}
-  // expected-complete-tns-error @-1 {{type '@Sendable () -> Void'}}
+  // expected-complete-error @-1 {{type '@Sendable () -> Void'}}
   let _: Int = X[statically: { onMainActor() }] // expected-minimal-targeted-error {{type '() -> Void'}}
-  // expected-complete-tns-error @-1 {{type '@Sendable () -> Void'}}
+  // expected-complete-error @-1 {{type '@Sendable () -> Void'}}
 }
 
 @MainActor @preconcurrency func onMainActorAlways() { }
-// expected-complete-tns-note @-1 {{calls to global function 'onMainActorAlways()' from outside of its actor context are implicitly asynchronous}}
+// expected-complete-note @-1 {{calls to global function 'onMainActorAlways()' from outside of its actor context are implicitly asynchronous}}
 
 @preconcurrency @MainActor class MyModelClass {
 
   // default init() is 'nonisolated' in '-strict-concurrency=complete'
 
   func f() { }
-  // expected-complete-tns-note @-1 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+  // expected-complete-note @-1 {{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
 }
 
 func testCalls(x: X) {
-  // expected-complete-tns-note @-1 2{{add '@MainActor' to make global function 'testCalls(x:)' part of global actor 'MainActor'}}
+  // expected-complete-note @-1 2{{add '@MainActor' to make global function 'testCalls(x:)' part of global actor 'MainActor'}}
   unsafelyMainActorClosure {
     onMainActor()
   }
@@ -99,28 +97,25 @@ func testCalls(x: X) {
     })
 
   onMainActorAlways() // okay with minimal/targeted concurrency. Not ok with complete.
-  // expected-complete-tns-warning @-1 {{call to main actor-isolated global function 'onMainActorAlways()' in a synchronous nonisolated context}}
+  // expected-complete-warning @-1 {{call to main actor-isolated global function 'onMainActorAlways()' in a synchronous nonisolated context}}
 
   // Ok with minimal/targeted concurrency, Not ok with complete.
-  let _: () -> Void = onMainActorAlways // expected-complete-tns-warning {{converting function value of type '@MainActor () -> ()' to '() -> Void' loses global actor 'MainActor'}}
+  let _: () -> Void = onMainActorAlways // expected-complete-warning {{converting function value of type '@MainActor () -> ()' to '() -> Void' loses global actor 'MainActor'}}
 
   let c = MyModelClass()
 
   // okay with minimal/targeted... an error with complete.
-  c.f() // expected-complete-tns-warning {{call to main actor-isolated instance method 'f()' in a synchronous nonisolated context}}
+  c.f() // expected-complete-warning {{call to main actor-isolated instance method 'f()' in a synchronous nonisolated context}}
 }
 
 func testCallsWithAsync() async {
-  onMainActorAlways() // expected-warning{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{calls to global function 'onMainActorAlways()' from outside of its actor context are implicitly asynchronous}}
+  onMainActorAlways() // expected-warning{{main actor-isolated global function 'onMainActorAlways()' cannot be called from outside of the actor}} {{3-3=await }}
 
   let _: () -> Void = onMainActorAlways // expected-warning {{converting function value of type '@MainActor () -> ()' to '() -> Void' loses global actor 'MainActor'}}
 
-  let c = MyModelClass() // expected-minimal-targeted-warning{{expression is 'async' but is not marked with 'await'}}
-  // expected-minimal-targeted-note@-1{{calls to initializer 'init()' from outside of its actor context are implicitly asynchronous}}
+  let c = MyModelClass() // expected-minimal-targeted-warning{{main actor-isolated initializer 'init()' cannot be called from outside of the actor}} {{11-11=await }}
 
-  c.f() // expected-warning{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+  c.f() // expected-warning{{main actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{3-3=await }}
 }
 
 // ---------------------------------------------------------------------------
@@ -130,28 +125,28 @@ func testCallsWithAsync() async {
 protocol Q: P { }
 
 class NS { } // expected-note{{class 'NS' does not conform to the 'Sendable' protocol}}
-// expected-complete-tns-note @-1 2{{class 'NS' does not conform to the 'Sendable' protocol}}
+// expected-complete-note @-1 2{{class 'NS' does not conform to the 'Sendable' protocol}}
 
 struct S1: P {
-  var ns: NS // expected-complete-tns-warning {{stored property 'ns' of 'Sendable'-conforming struct 'S1' has non-sendable type 'NS'}}
+  var ns: NS // expected-complete-warning {{stored property 'ns' of 'Sendable'-conforming struct 'S1' has non-Sendable type 'NS'}}
 }
 
 struct S2: Q {
-  var ns: NS // expected-complete-tns-warning {{stored property 'ns' of 'Sendable'-conforming struct 'S2' has non-sendable type 'NS'}}
+  var ns: NS // expected-complete-warning {{stored property 'ns' of 'Sendable'-conforming struct 'S2' has non-Sendable type 'NS'}}
 }
 
 struct S3: Q, Sendable {
-  var ns: NS // expected-warning{{stored property 'ns' of 'Sendable'-conforming struct 'S3' has non-sendable type 'NS'}}
+  var ns: NS // expected-warning{{stored property 'ns' of 'Sendable'-conforming struct 'S3' has non-Sendable type 'NS'}}
 }
 
 // ---------------------------------------------------------------------------
 // Historical attribute names do nothing (but are permitted)
 // ---------------------------------------------------------------------------
 func aFailedExperiment(@_unsafeSendable _ body: @escaping () -> Void) { }
-// expected-warning@-1{{'_unsafeSendable' attribute has been removed in favor of @preconcurrency}}
+// expected-warning@-1{{'_unsafeSendable' attribute has been removed in favor of '@preconcurrency'}}
 
 func anothingFailedExperiment(@_unsafeMainActor _ body: @escaping () -> Void) { }
-// expected-warning@-1{{'_unsafeMainActor' attribute has been removed in favor of @preconcurrency}}
+// expected-warning@-1{{'_unsafeMainActor' attribute has been removed in favor of '@preconcurrency'}}
 
 // ---------------------------------------------------------------------------
 // Random bugs
@@ -174,11 +169,11 @@ public enum StringPlacement : Sendable {
 func testStringPlacement() {
   let fn1 = StringPlacement.position(before: "Test")
   let _: Int = fn1   // expected-minimal-targeted-error{{cannot convert value of type '([String]) -> Int' to specified type 'Int'}}
-  // expected-complete-tns-error @-1 {{type 'StringPlacement.StringPosition' (aka '@Sendable (Array<String>) -> Int')}}
+  // expected-complete-error @-1 {{type 'StringPlacement.StringPosition' (aka '@Sendable (Array<String>) -> Int')}}
 
   let fn2 = StringPlacement.position(before:)
   let _: Int = fn2 // expected-minimal-targeted-error{{cannot convert value of type '(String) -> ([String]) -> Int' to specified type 'Int'}}
-  // expected-complete-tns-error @-1 {{type '(String) -> StringPlacement.StringPosition' (aka '(String) -> @Sendable (Array<String>) -> Int')}}
+  // expected-complete-error @-1 {{type '(String) -> StringPlacement.StringPosition' (aka '(String) -> @Sendable (Array<String>) -> Int')}}
 }
 
 // @preconcurrency in an outer closure
@@ -194,17 +189,17 @@ class EventLoop {
   func scheduleTask<T>(deadline: Int, _ task: @escaping @Sendable () throws -> T) -> Scheduled<T> { fatalError("") }
 }
 
-class C { // expected-complete-tns-note {{'C' does not conform to the 'Sendable' protocol}}
+class C { // expected-complete-note {{'C' does not conform to the 'Sendable' protocol}}
   var ev: EventLoop? = nil
 
   func test(i: Int) {
-    func doNext() { // expected-complete-tns-warning {{concurrently-executed local function 'doNext()' must be marked as '@Sendable'}}
+    func doNext() { // expected-complete-warning {{concurrently-executed local function 'doNext()' must be marked as '@Sendable'}}
       doPreconcurrency {
         self.ev?.scheduleTask(deadline: i, doNext)
-        // expected-complete-tns-warning @-1 {{capture of 'self' with non-sendable type 'C' in a '@Sendable' closure}}
-        // expected-complete-tns-warning @-2 {{converting non-sendable function value to '@Sendable () throws -> ()' may introduce data races}}
-        // expected-complete-tns-warning @-3 {{capture of 'doNext()' with non-sendable type '() -> ()' in a '@Sendable' closure}}
-        // expected-complete-tns-note @-4 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+        // expected-complete-warning @-1 {{capture of 'self' with non-Sendable type 'C' in a '@Sendable' closure}}
+        // expected-complete-warning @-2 {{converting non-Sendable function value to '@Sendable () throws -> ()' may introduce data races}}
+        // expected-complete-warning @-3 {{capture of 'doNext()' with non-Sendable type '() -> ()' in a '@Sendable' closure}}
+        // expected-complete-note @-4 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
         return
       }
     }
@@ -229,25 +224,25 @@ protocol NotIsolated {
   func requirement()
 }
 
-// expected-complete-tns-warning@+1{{conformance of 'MainActorPreconcurrency' to protocol 'NotIsolated' crosses into main actor-isolated code and can cause data races}}
+// expected-complete-warning@+1{{conformance of 'MainActorPreconcurrency' to protocol 'NotIsolated' crosses into main actor-isolated code and can cause data races}}
 extension MainActorPreconcurrency: NotIsolated {
-  // expected-complete-note@-1{{add '@preconcurrency' to the 'NotIsolated' conformance to suppress isolation-related diagnostics}}{{36-36=@preconcurrency }}
-  // expected-complete-tns-note@-2{{turn data races into runtime errors with '@preconcurrency'}}{{36-36=@preconcurrency }}
-  // expected-complete-tns-note@-3{{mark all declarations used in the conformance 'nonisolated'}}
+  // expected-complete-note@-1{{turn data races into runtime errors with '@preconcurrency'}}{{36-36=@preconcurrency }}
+  // expected-complete-note@-2{{mark all declarations used in the conformance 'nonisolated'}}
+  // expected-complete-note@-3{{isolate this conformance to the main actor with '@MainActor'}}
   func requirement() {}
-  // expected-complete-tns-note@-1 {{main actor-isolated instance method 'requirement()' cannot satisfy nonisolated requirement}}
-  // expected-complete-tns-note@-2 {{calls to instance method 'requirement()' from outside of its actor context are implicitly asynchronous}}
+  // expected-complete-note@-1 {{main actor-isolated instance method 'requirement()' cannot satisfy nonisolated requirement}}
+  // expected-complete-note@-2 {{calls to instance method 'requirement()' from outside of its actor context are implicitly asynchronous}}
 
 
   class Nested {
     weak var c: MainActorPreconcurrency?
 
     func test() {
-    // expected-complete-tns-note@-1 {{add '@MainActor' to make instance method 'test()' part of global actor 'MainActor'}}
+    // expected-complete-note@-1 {{add '@MainActor' to make instance method 'test()' part of global actor 'MainActor'}}
 
       if let c {
         c.requirement()
-        // expected-complete-tns-warning@-1 {{call to main actor-isolated instance method 'requirement()' in a synchronous nonisolated context}}
+        // expected-complete-warning@-1 {{call to main actor-isolated instance method 'requirement()' in a synchronous nonisolated context}}
       }
     }
   }
@@ -359,3 +354,39 @@ do {
     }
   }
 }
+
+func testSendableMetatypeDowngrades() {
+  @preconcurrency
+  func acceptsSendableMetatype<T: SendableMetatype>(_: T.Type) {}
+  func acceptsSendableMetatypeStrict<T: SendableMetatype>(_: T.Type) {}
+
+  func test<T>(t: T.Type) { // expected-complete-note 2 {{consider making generic parameter 'T' conform to the 'SendableMetatype' protocol}} {{14-14=: SendableMetatype}}
+    acceptsSendableMetatype(t)
+    // expected-complete-warning@-1 {{type 'T' does not conform to the 'SendableMetatype' protocol}}
+    acceptsSendableMetatypeStrict(t)
+    // expected-complete-warning@-1 {{type 'T' does not conform to the 'SendableMetatype' protocol}}
+  }
+}
+
+do {
+  func test(@_inheritActorContext _: @Sendable () -> Void) async {
+    // expected-warning@-1 {{@_inheritActorContext only applies to '@isolated(any)' parameters or parameters with asynchronous function types; this will be an error in a future Swift language mode}}
+  }
+
+  @MainActor
+  @preconcurrency
+  class Test {
+    struct V {}
+
+    var value: V? // expected-note {{property declared here}}
+
+    func run() async {
+      await test {
+        if let value {
+          // expected-warning@-1 {{main actor-isolated property 'value' can not be referenced from a Sendable closure}}
+          print(value)
+        }
+      }
+    }
+  }
+}
diff --git a/test/Concurrency/predates_concurrency_import.swift b/test/Concurrency/predates_concurrency_import.swift
index 1f50a49768a70..26b9e520be16b 100644
--- a/test/Concurrency/predates_concurrency_import.swift
+++ b/test/Concurrency/predates_concurrency_import.swift
@@ -3,9 +3,9 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/NonStrictModule.swiftmodule -module-name NonStrictModule %S/Inputs/NonStrictModule.swift
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/OtherActors.swiftmodule -module-name OtherActors %S/Inputs/OtherActors.swift -target %target-swift-5.1-abi-triple
 
-// RUN: %target-swift-frontend  -I %t %s -emit-sil -o /dev/null -verify  -parse-as-library -enable-upcoming-feature GlobalConcurrency -Wwarning PreconcurrencyImport
-// RUN: %target-swift-frontend  -I %t %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted -parse-as-library -enable-upcoming-feature GlobalConcurrency -Wwarning PreconcurrencyImport
-// RUN: %target-swift-frontend  -I %t %s -emit-sil -o /dev/null -verify -strict-concurrency=complete  -parse-as-library -enable-upcoming-feature GlobalConcurrency -Wwarning PreconcurrencyImport
+// RUN: %target-swift-frontend  -I %t %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated  -parse-as-library -enable-upcoming-feature GlobalConcurrency -Wwarning PreconcurrencyImport
+// RUN: %target-swift-frontend  -I %t %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=targeted -parse-as-library -enable-upcoming-feature GlobalConcurrency -Wwarning PreconcurrencyImport
+// RUN: %target-swift-frontend  -I %t %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=complete  -parse-as-library -enable-upcoming-feature GlobalConcurrency -Wwarning PreconcurrencyImport
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalConcurrency
@@ -13,7 +13,7 @@
 @preconcurrency import NonStrictModule
 @_predatesConcurrency import StrictModule // expected-warning{{'@_predatesConcurrency' has been renamed to '@preconcurrency'}}
 @preconcurrency import OtherActors
-// expected-warning@-1{{'@preconcurrency' attribute on module 'OtherActors' has no effect}}{{1-17=}}
+// expected-warning@-1{{'@preconcurrency' on module 'OtherActors' has no effect}}{{1-17=}}
 
 @preconcurrency
 class MyPredatesConcurrencyClass { }
diff --git a/test/Concurrency/predates_concurrency_import_deinit.swift b/test/Concurrency/predates_concurrency_import_deinit.swift
index 9ad134b0ff3b9..5f243bcf73db0 100644
--- a/test/Concurrency/predates_concurrency_import_deinit.swift
+++ b/test/Concurrency/predates_concurrency_import_deinit.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/StrictModule.swiftmodule -module-name StrictModule -swift-version 6 %S/Inputs/StrictModule.swift
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/NonStrictModule.swiftmodule -module-name NonStrictModule %S/Inputs/NonStrictModule.swift
 
-// RUN: %target-swift-frontend  -I %t %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
+// RUN: %target-swift-frontend  -I %t %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=complete
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
@@ -17,6 +17,6 @@ actor ActorWithDeinit {
 
   deinit {
     print(ns)
-    print(ss) // expected-warning{{cannot access property 'ss' with a non-sendable type 'StrictStruct' from nonisolated deinit}}
+    print(ss) // expected-warning{{cannot access property 'ss' with a non-Sendable type 'StrictStruct' from nonisolated deinit}}
   }
 }
diff --git a/test/Concurrency/predates_concurrency_import_emitmodule.swift b/test/Concurrency/predates_concurrency_import_emitmodule.swift
index 503a43eed0a8f..ac1dd71350158 100644
--- a/test/Concurrency/predates_concurrency_import_emitmodule.swift
+++ b/test/Concurrency/predates_concurrency_import_emitmodule.swift
@@ -6,10 +6,8 @@
 // RUN: %target-swift-frontend -emit-module -I %t -verify -primary-file %s -emit-module-path %t/predates_concurrency_import_swiftmodule.swiftmodule -experimental-skip-all-function-bodies
 // RUN: %target-swift-frontend -emit-module -I %t -verify -primary-file %s -emit-module-path %t/predates_concurrency_import_swiftmodule.swiftmodule -experimental-skip-all-function-bodies -strict-concurrency=targeted
 // RUN: %target-swift-frontend -emit-module -I %t -verify -primary-file %s -emit-module-path %t/predates_concurrency_import_swiftmodule.swiftmodule -experimental-skip-all-function-bodies -strict-concurrency=complete
-// RUN: %target-swift-frontend -emit-module -I %t -verify -primary-file %s -emit-module-path %t/predates_concurrency_import_swiftmodule.swiftmodule -experimental-skip-all-function-bodies -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @preconcurrency import NonStrictModule
 @preconcurrency import StrictModule
diff --git a/test/Concurrency/predates_concurrency_import_swift6.swift b/test/Concurrency/predates_concurrency_import_swift6.swift
index 5df3b31fb02a0..90447bdaeace3 100644
--- a/test/Concurrency/predates_concurrency_import_swift6.swift
+++ b/test/Concurrency/predates_concurrency_import_swift6.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/StrictModule.swiftmodule -module-name StrictModule -swift-version 6 %S/Inputs/StrictModule.swift
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/NonStrictModule.swiftmodule -module-name NonStrictModule %S/Inputs/NonStrictModule.swift
 
-// RUN: %target-swift-frontend -swift-version 6 -I %t %s -emit-sil -o /dev/null -verify -parse-as-library
+// RUN: %target-swift-frontend -swift-version 6 -I %t %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -parse-as-library
 
 @preconcurrency import NonStrictModule
 @preconcurrency import StrictModule
diff --git a/test/Concurrency/predates_concurrency_swift6.swift b/test/Concurrency/predates_concurrency_swift6.swift
index be5919eec051a..b5fbc2b595e58 100644
--- a/test/Concurrency/predates_concurrency_swift6.swift
+++ b/test/Concurrency/predates_concurrency_swift6.swift
@@ -63,25 +63,23 @@ func testElsewhere(x: X) {
 
 func testCalls(x: X) {
   // expected-note@-1 2{{add '@MainActor' to make global function 'testCalls(x:)' part of global actor 'MainActor'}}
-  onMainActorAlways() // expected-error{{call to main actor-isolated global function 'onMainActorAlways()' in a synchronous nonisolated context}}
+  onMainActorAlways() // expected-warning{{call to main actor-isolated global function 'onMainActorAlways()' in a synchronous nonisolated context}}
 
   let _: () -> Void = onMainActorAlways // expected-error{{converting function value of type '@MainActor @Sendable () -> ()' to '() -> Void' loses global actor 'MainActor'}}
 
   let c = MyModelClass() // okay, synthesized init() is 'nonisolated'
 
-  c.f() // expected-error{{call to main actor-isolated instance method 'f()' in a synchronous nonisolated context}}
+  c.f() // expected-warning{{call to main actor-isolated instance method 'f()' in a synchronous nonisolated context}}
 }
 
 func testCallsWithAsync() async {
-  onMainActorAlways() // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{calls to global function 'onMainActorAlways()' from outside of its actor context are implicitly asynchronous}}
+  onMainActorAlways() // expected-error{{main actor-isolated global function 'onMainActorAlways()' cannot be called from outside of the actor}} {{3-3=await }}
 
   let _: () -> Void = onMainActorAlways // expected-error{{converting function value of type '@MainActor @Sendable () -> ()' to '() -> Void' loses global actor 'MainActor'}}
 
   let c = MyModelClass() // okay, synthesized init() is 'nonisolated'
 
-  c.f() // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+  c.f() // expected-error{{main actor-isolated instance method 'f()' cannot be called from outside of the actor}} {{3-3=await }}
 }
 
 // ---------------------------------------------------------------------------
@@ -90,28 +88,28 @@ func testCallsWithAsync() async {
 @preconcurrency protocol P: Sendable { }
 protocol Q: P { }
 
-class NS { } // expected-note 3{{class 'NS' does not conform to the 'Sendable' protocol}}
+class NS { } // expected-note 5{{class 'NS' does not conform to the 'Sendable' protocol}}
 
 struct S1: P {
-  var ns: NS // expected-error{{stored property 'ns' of 'Sendable'-conforming struct 'S1' has non-sendable type 'NS'}}
+  var ns: NS // expected-warning{{stored property 'ns' of 'Sendable'-conforming struct 'S1' has non-Sendable type 'NS'}}
 }
 
 struct S2: Q {
-  var ns: NS // expected-error{{stored property 'ns' of 'Sendable'-conforming struct 'S2' has non-sendable type 'NS'}}
+  var ns: NS // expected-warning{{stored property 'ns' of 'Sendable'-conforming struct 'S2' has non-Sendable type 'NS'}}
 }
 
 struct S3: Q, Sendable {
-  var ns: NS // expected-error{{stored property 'ns' of 'Sendable'-conforming struct 'S3' has non-sendable type 'NS'}}
+  var ns: NS // expected-error{{stored property 'ns' of 'Sendable'-conforming struct 'S3' has non-Sendable type 'NS'}}
 }
 
 // ---------------------------------------------------------------------------
 // Historical attribute names do nothing (but are permitted)
 // ---------------------------------------------------------------------------
 func aFailedExperiment(@_unsafeSendable _ body: @escaping () -> Void) { }
-// expected-warning@-1{{'_unsafeSendable' attribute has been removed in favor of @preconcurrency}}
+// expected-warning@-1{{'_unsafeSendable' attribute has been removed in favor of '@preconcurrency'}}
 
 func anothingFailedExperiment(@_unsafeMainActor _ body: @escaping () -> Void) { }
-// expected-warning@-1{{'_unsafeMainActor' attribute has been removed in favor of @preconcurrency}}
+// expected-warning@-1{{'_unsafeMainActor' attribute has been removed in favor of '@preconcurrency'}}
 
 // Override matching with @preconcurrency properties.
 do {
@@ -189,7 +187,7 @@ func withSendableClosure(_: @Sendable () -> Void) {}
 func conversionDowngrade() {
   let ns: () -> Void = {}
   withSendableClosure(ns)
-  // expected-warning@-1 {{converting non-sendable function value to '@Sendable () -> Void' may introduce data races}}
+  // expected-warning@-1 {{converting non-Sendable function value to '@Sendable () -> Void' may introduce data races}}
 }
 
 @preconcurrency
@@ -311,3 +309,76 @@ do {
   // If destination is @preconcurrency the Sendable conformance error should be downgraded
   d = data // expected-warning {{type 'Any' does not conform to the 'Sendable' protocol}}
 }
+
+do {
+  final class Mutating: P {
+    var state: Int = 0 // expected-warning {{stored property 'state' of 'Sendable'-conforming class 'Mutating' is mutable}}
+  }
+
+  struct StructWithInit: P {
+    let prop = NS() // expected-warning {{stored property 'prop' of 'Sendable'-conforming struct 'StructWithInit' has non-Sendable type 'NS'}}
+  }
+
+  enum E : P {
+    case test(NS) // expected-warning {{associated value 'test' of 'Sendable'-conforming enum 'E' has non-Sendable type 'NS'}}
+  }
+}
+
+func testSendableMetatypeDowngrades() {
+  @preconcurrency
+  func acceptsSendableMetatype<T: SendableMetatype>(_: T.Type) {}
+  func acceptsSendableMetatypeStrict<T: SendableMetatype>(_: T.Type) {}
+
+  func testWarning<T>(t: T.Type) { // expected-note 2 {{consider making generic parameter 'T' conform to the 'SendableMetatype' protocol}} {{21-21=: SendableMetatype}}
+    acceptsSendableMetatype(t) // expected-warning {{type 'T' does not conform to the 'SendableMetatype' protocol}}
+    acceptsSendableMetatypeStrict(t) // expected-error {{type 'T' does not conform to the 'SendableMetatype' protocol}}
+  }
+
+  func testOK<T: P>(t: T.Type) {
+    acceptsSendableMetatype(t) // Ok (because P is `Sendable`
+  }
+}
+
+// Test that Sendable issues are downgraded to warnings in `@preconcurrency` context.
+do {
+  @preconcurrency nonisolated func f(callback: @Sendable () -> Void) {}
+
+  @MainActor
+  struct Env {
+    var v: Int = 0
+  }
+
+  @MainActor
+  class IsolatedTest {
+    var env = Env()
+    // expected-note@-1 {{property declared here}}
+
+    func onMain() {}
+    // expected-note@-1 {{calls to instance method 'onMain()' from outside of its actor context are implicitly asynchronous}}
+
+    func testProperty() {
+      f {
+        _ = self.env.v
+        // expected-warning@-1 {{main actor-isolated property 'env' can not be referenced from a Sendable closure}}
+      }
+    }
+
+    func testMethod() {
+      f {
+        self.onMain()
+        // expected-warning@-1 {{call to main actor-isolated instance method 'onMain()' in a synchronous nonisolated context}}
+      }
+    }
+  }
+
+  class Test { // expected-note {{class 'Test' does not conform to the 'Sendable' protocol}}
+    var env = Env()
+
+    func testProperty() async {
+      f {
+        _ = self.env.v
+        // expected-warning@-1 {{capture of 'self' with non-Sendable type 'Test' in a '@Sendable' closure}}
+      }
+    }
+  }
+}
diff --git a/test/Concurrency/radar_concurrency_nio.swift b/test/Concurrency/radar_concurrency_nio.swift
index f4172d3463c20..72658fd8e4701 100644
--- a/test/Concurrency/radar_concurrency_nio.swift
+++ b/test/Concurrency/radar_concurrency_nio.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend -enable-experimental-move-only -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -enable-experimental-move-only -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -enable-experimental-move-only -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -enable-experimental-move-only -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 public protocol EventLoop: Sendable {}
 
diff --git a/test/Concurrency/reasync.swift b/test/Concurrency/reasync.swift
index d04e179458858..5286395e62137 100644
--- a/test/Concurrency/reasync.swift
+++ b/test/Concurrency/reasync.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -enable-experimental-concurrency -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 //// Basic definitions and parsing
 
diff --git a/test/Concurrency/redundant_sendable_conformance.swift b/test/Concurrency/redundant_sendable_conformance.swift
index 956636e695ec4..f5d2fe2ca53e3 100644
--- a/test/Concurrency/redundant_sendable_conformance.swift
+++ b/test/Concurrency/redundant_sendable_conformance.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/SendableConformances.swiftmodule -module-name SendableConformances %S/Inputs/SendableConformances.swift
 
-// RUN: %target-swift-frontend -typecheck %s -verify -swift-version 6 -I %t
+// RUN: %target-swift-frontend -typecheck %s -verify -verify-ignore-unrelated -swift-version 6 -I %t
 
 // REQUIRES: concurrency
 
diff --git a/test/Concurrency/regionanalysis_trackable_value.sil b/test/Concurrency/regionanalysis_trackable_value.sil
new file mode 100644
index 0000000000000..ec8c9bd0cf5f5
--- /dev/null
+++ b/test/Concurrency/regionanalysis_trackable_value.sil
@@ -0,0 +1,725 @@
+// RUN: %target-sil-opt -module-name infer --test-runner %s 2>&1 | %FileCheck %s
+
+// REQUIRES: concurrency
+// REQUIRES: asserts
+
+// PLEASE READ THIS!
+//
+// This test is specifically meant to test how we look through underlying
+// objects for region analysis.
+
+sil_stage raw
+
+import Swift
+import Builtin
+import _Concurrency
+
+////////////////////////
+// MARK: Declarations //
+////////////////////////
+
+class NonSendableKlass {
+}
+
+class SendableKlass : @unchecked Sendable {
+}
+
+struct Struct2 {
+  let nsLet: NonSendableKlass
+  let sLet: SendableKlass
+  var nsVar: NonSendableKlass
+  var sVar: SendableKlass
+}
+
+struct Struct {
+  let nsLet: NonSendableKlass
+  let sLet: SendableKlass
+  var nsVar: NonSendableKlass
+  var sVar: SendableKlass
+
+  let struct2Let: Struct2
+  var struct2Var: Struct2
+
+  let sStruct: SendableStruct
+}
+
+struct SendableStruct : @unchecked Sendable {
+  let nsLet: NonSendableKlass
+}
+
+class NonSendableKlassWithState {
+  let sLet: Struct
+  var sVar: Struct
+  let recurseLet: NonSendableKlassWithState?
+  var recurseVar: NonSendableKlassWithState?
+}
+
+actor Custom {}
+
+enum MyEnum<T> {
+    case none
+    indirect case some(NonSendableKlass)
+    case some2(T)
+}
+
+sil @transferNonSendableKlass : $@convention(thin) @async (@guaranteed NonSendableKlass) -> ()
+sil @useNonSendableKlass : $@convention(thin) (@guaranteed NonSendableKlass) -> ()
+sil @constructNonSendableKlass : $@convention(thin) () -> @owned NonSendableKlass
+sil @constructStruct : $@convention(thin) () -> @owned Struct
+sil @constructSendableStruct : $@convention(thin) () -> @owned SendableStruct
+
+sil @transferIndirect : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+
+/////////////////
+// MARK: Tests //
+/////////////////
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_direct_access: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var NonSendableKlass }
+// CHECK: end running test 1 of 1 on allocbox_direct_access: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_direct_access : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructNonSendableKlass : $@convention(thin) () -> @owned NonSendableKlass
+  %c = apply %f() : $@convention(thin) () -> @owned NonSendableKlass
+  %a = alloc_box ${ var NonSendableKlass }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*NonSendableKlass
+
+  debug_value [trace] %p
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_nonsendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_nonsendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_nonsendable_let : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %nsLet = struct_element_addr %p : $*Struct, #Struct.nsLet
+  debug_value [trace] %nsLet
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_nonsendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_nonsendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_nonsendable_var : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %nsVar = struct_element_addr %p : $*Struct, #Struct.nsVar
+  debug_value [trace] %nsVar
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_sendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %6 = struct_element_addr %4 : $*Struct, #Struct.sLet
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_sendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_sendable_let : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %addr = struct_element_addr %p : $*Struct, #Struct.sLet
+  debug_value [trace] %addr
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_sendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %6 = struct_element_addr %4 : $*Struct, #Struct.sVar
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_sendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_sendable_var : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %addr = struct_element_addr %p : $*Struct, #Struct.sVar
+  debug_value [trace] %addr
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_let_grandfield_nonsendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_let_grandfield_nonsendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_let_grandfield_nonsendable_let : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %s2 = struct_element_addr %p : $*Struct, #Struct.struct2Let
+  %nsLet = struct_element_addr %s2 : $*Struct2, #Struct2.nsLet
+
+  debug_value [trace] %nsLet
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_let_grandfield_nonsendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_let_grandfield_nonsendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_let_grandfield_nonsendable_var : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p
+
+  %s2 = struct_element_addr %p : $*Struct, #Struct.struct2Let
+  %nsVar = struct_element_addr %s2 : $*Struct2, #Struct2.nsVar
+  debug_value [trace] %nsVar
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_let_grandfield_sendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %7 = struct_element_addr %6 : $*Struct2, #Struct2.sLet
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_let_grandfield_sendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_let_grandfield_sendable_let : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %s2 = struct_element_addr %p : $*Struct, #Struct.struct2Let
+  %addr = struct_element_addr %s2 : $*Struct2, #Struct2.sLet
+  debug_value [trace] %addr
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_let_grandfield_sendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %7 = struct_element_addr %6 : $*Struct2, #Struct2.sVar
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_let_grandfield_sendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_let_grandfield_sendable_var : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %s2 = struct_element_addr %p : $*Struct, #Struct.struct2Let
+  %addr = struct_element_addr %s2 : $*Struct2, #Struct2.sVar
+  debug_value [trace] %addr
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_var_grandfield_nonsendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_var_grandfield_nonsendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_var_grandfield_nonsendable_let : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %s2 = struct_element_addr %p : $*Struct, #Struct.struct2Var
+  %nsLet = struct_element_addr %s2 : $*Struct2, #Struct2.nsLet
+
+  debug_value [trace] %nsLet
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_var_grandfield_nonsendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_var_grandfield_nonsendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_var_grandfield_nonsendable_var : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p
+
+  %s2 = struct_element_addr %p : $*Struct, #Struct.struct2Var
+  %nsVar = struct_element_addr %s2 : $*Struct2, #Struct2.nsVar
+  debug_value [trace] %nsVar
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_var_grandfield_sendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %7 = struct_element_addr %6 : $*Struct2, #Struct2.sLet
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_var_grandfield_sendable_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_var_grandfield_sendable_let : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %s2 = struct_element_addr %p : $*Struct, #Struct.struct2Var
+  %addr = struct_element_addr %s2 : $*Struct2, #Struct2.sLet
+  debug_value [trace] %addr
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_struct_field_var_grandfield_sendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %7 = struct_element_addr %6 : $*Struct2, #Struct2.sVar
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var Struct }
+// CHECK: end running test 1 of 1 on allocbox_access_struct_field_var_grandfield_sendable_var: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_struct_field_var_grandfield_sendable_var : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructStruct : $@convention(thin) () -> @owned Struct
+  %c = apply %f() : $@convention(thin) () -> @owned Struct
+  %a = alloc_box ${ var Struct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p : $*Struct
+
+  %s2 = struct_element_addr %p : $*Struct, #Struct.struct2Var
+  %addr = struct_element_addr %s2 : $*Struct2, #Struct2.sVar
+  debug_value [trace] %addr
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_sendable_struct_field_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: yes][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %6 = struct_element_addr %4 : $*SendableStruct, #SendableStruct.nsLet
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_box ${ var SendableStruct }
+// CHECK: end running test 1 of 1 on allocbox_access_sendable_struct_field_let: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_sendable_struct_field_let : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructSendableStruct : $@convention(thin) () -> @owned SendableStruct
+  %c = apply %f() : $@convention(thin) () -> @owned SendableStruct
+  %a = alloc_box ${ var SendableStruct }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %c to [init] %p
+
+  %s2 = struct_element_addr %p : $*SendableStruct, #SendableStruct.nsLet
+  debug_value [trace] %s2
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on allocbox_access_sendable_struct_field_let_2: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: yes][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %4 = struct_element_addr %2 : $*SendableStruct, #SendableStruct.nsLet
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = alloc_stack $SendableStruct
+// CHECK: end running test 1 of 1 on allocbox_access_sendable_struct_field_let_2: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @allocbox_access_sendable_struct_field_let_2 : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %f = function_ref @constructSendableStruct : $@convention(thin) () -> @owned SendableStruct
+  %c = apply %f() : $@convention(thin) () -> @owned SendableStruct
+  %a = alloc_stack $SendableStruct
+  store %c to [init] %a
+
+  %s2 = struct_element_addr %a : $*SendableStruct, #SendableStruct.nsLet
+  debug_value [trace] %s2
+
+  destroy_addr %a
+  dealloc_stack %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on class_lookthrough_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %6 = ref_element_addr %5 : $NonSendableKlassWithState, #NonSendableKlassWithState.sLet
+// CHECK: end running test 1 of 1 on class_lookthrough_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @class_lookthrough_test : $@convention(thin) (@owned NonSendableKlassWithState) -> () {
+bb0(%0 : @owned $NonSendableKlassWithState):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %a = alloc_box ${ var NonSendableKlassWithState }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %0 to [init] %p : $*NonSendableKlassWithState
+
+  %p2 = load_borrow %p
+  %s = ref_element_addr %p2 : $NonSendableKlassWithState, #NonSendableKlassWithState.sLet
+  debug_value [trace] %s
+  end_borrow %p2
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// We model unchecked_enum_data as an assign, so we do not look through it. The
+// result of this is that we consider it a separate value (even though we could
+// cheat potentially).
+//
+// CHECK-LABEL: begin running test 1 of 1 on class_lookthrough_test_2: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:    Rep Value:   %6 = ref_element_addr %5 : $NonSendableKlassWithState, #NonSendableKlassWithState.recurseLet
+// CHECK: end running test 1 of 1 on class_lookthrough_test_2: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @class_lookthrough_test_2 : $@convention(thin) (@owned NonSendableKlassWithState) -> () {
+bb0(%0 : @owned $NonSendableKlassWithState):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %a = alloc_box ${ var NonSendableKlassWithState }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %0 to [init] %p : $*NonSendableKlassWithState
+
+  %p2 = load_borrow %p
+  %s = ref_element_addr %p2 : $NonSendableKlassWithState, #NonSendableKlassWithState.recurseLet
+  %s2 = load_borrow %s
+  %s3 = unchecked_enum_data %s2 : $Optional<NonSendableKlassWithState>, #Optional.some!enumelt
+  debug_value [trace] %s3
+  end_borrow %s2
+  end_borrow %p2
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// We always stop at ref_element_addr since it is a base of a value.
+//
+// CHECK-LABEL: begin running test 1 of 1 on class_lookthrough_test_3: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:   Rep Value:   %9 = ref_element_addr %8 : $NonSendableKlassWithState, #NonSendableKlassWithState.sLet
+// CHECK: end running test 1 of 1 on class_lookthrough_test_3: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @class_lookthrough_test_3 : $@convention(thin) (@owned NonSendableKlassWithState) -> () {
+bb0(%0 : @owned $NonSendableKlassWithState):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %a = alloc_box ${ var NonSendableKlassWithState }
+  %ab = begin_borrow %a
+  %p = project_box %ab, 0
+  store %0 to [init] %p : $*NonSendableKlassWithState
+
+  %p2 = load_borrow %p
+  %s = ref_element_addr %p2 : $NonSendableKlassWithState, #NonSendableKlassWithState.recurseLet
+  %s2 = load_borrow %s
+  %s3 = unchecked_enum_data %s2 : $Optional<NonSendableKlassWithState>, #Optional.some!enumelt
+  %s4 = ref_element_addr %s3 : $NonSendableKlassWithState, #NonSendableKlassWithState.sLet
+  debug_value [trace] %s4
+  end_borrow %s2
+  end_borrow %p2
+
+  end_borrow %ab
+  destroy_value %a
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on actor_deinit_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %2 = unchecked_ref_cast %0 : $Custom to $Builtin.NativeObject
+// CHECK: end running test 1 of 1 on actor_deinit_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @actor_deinit_test : $@convention(thin) (@guaranteed Custom) -> @owned Builtin.NativeObject {
+bb0(%0 : @guaranteed $Custom):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %2 = builtin "destroyDefaultActor"(%0) : $()
+  %3 = unchecked_ref_cast %0 to $Builtin.NativeObject
+  %4 = unchecked_ownership_conversion %3, @guaranteed to @owned
+  debug_value [trace] %3
+  return %4
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on project_box_loadable_test_case: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: yes][is_sendable: no][region_value_kind: task-isolated].
+// CHECK:    Rep Value: %0 = argument of bb0 : $*{ var NonSendableKlass }
+// CHECK: end running test 1 of 1 on project_box_loadable_test_case: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @project_box_loadable_test_case : $@convention(thin) @async (@in { var NonSendableKlass }) -> () {
+bb0(%0 : $*{ var NonSendableKlass }):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %1 = load [take] %0
+  %2 = project_box %1, 0
+  // function_ref transferIndirect
+  %3 = function_ref @transferIndirect : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  %4 = apply [callee_isolation=nonisolated] [caller_isolation=global_actor] %3<NonSendableKlass>(%2) : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  debug_value [trace] %2
+  destroy_value %1
+  %6 = tuple ()
+  return %6
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on deep_value_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: yes][is_sendable: no][region_value_kind: task-isolated].
+// CHECK:     Rep Value: %0 = argument of bb0 : $*{ var { var NonSendableKlass } }
+// CHECK: end running test 1 of 1 on deep_value_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @deep_value_test : $@convention(thin) @async (@in_guaranteed { var { var NonSendableKlass }  }) -> () {
+bb0(%0 : $*{ var { var NonSendableKlass } }):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %1 = load_borrow %0
+  %2 = project_box %1, 0
+  %3 = load_borrow %2
+  %4 = project_box %3, 0
+  // function_ref transferIndirect
+  %func = function_ref @transferIndirect : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  apply [callee_isolation=nonisolated] [caller_isolation=global_actor] %func<NonSendableKlass>(%4) : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  debug_value [trace] %4
+  end_borrow %3
+  end_borrow %1
+  %6 = tuple ()
+  return %6
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on deep_base_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %5 = struct_element_addr %4 : $*Struct2, #Struct2.sLet
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: yes][is_sendable: no][region_value_kind: task-isolated].
+// CHECK:     Rep Value: %0 = argument of bb0 : $*{ var { var Struct2 } }
+// CHECK: end running test 1 of 1 on deep_base_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @deep_base_test : $@convention(thin) @async (@in_guaranteed { var { var Struct2 }  }) -> () {
+bb0(%0 : $*{ var { var Struct2 } }):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %1 = load_borrow %0
+  %2 = project_box %1, 0
+  %3 = load_borrow %2
+  %4 = project_box %3, 0
+  %5 = struct_element_addr %4 : $*Struct2, #Struct2.sLet
+  // function_ref transferIndirect
+  %func = function_ref @transferIndirect : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  apply [callee_isolation=nonisolated] [caller_isolation=global_actor] %func<SendableKlass>(%5) : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  debug_value [trace] %5
+  end_borrow %3
+  end_borrow %1
+  %6 = tuple ()
+  return %6
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on alloc_stack_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: Value:
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %3 = struct_element_addr %1 : $*Struct2, #Struct2.sLet
+// CHECK: Base:
+// CHECK: TrackableValue. State: TrackableValueState[id: 1][is_no_alias: yes][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value:   %1 = alloc_stack $Struct2
+// CHECK: end running test 1 of 1 on alloc_stack_test: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @alloc_stack_test : $@convention(thin) @async (@owned Struct2) -> () {
+bb0(%0 : @owned $Struct2):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %1 = alloc_stack $Struct2, let
+  store %0 to [init] %1
+
+  %5 = struct_element_addr %1 : $*Struct2, #Struct2.sLet
+  %func = function_ref @transferIndirect : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  apply [callee_isolation=nonisolated] [caller_isolation=global_actor] %func<SendableKlass>(%5) : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  debug_value [trace] %5
+
+  destroy_addr %1
+  dealloc_stack %1
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on indirect_enum_load_take: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: yes][is_sendable: no][region_value_kind: disconnected].
+// CHECK:   Rep Value:   %1 = alloc_stack $MyEnum<T>
+// CHECK: end running test 1 of 1 on indirect_enum_load_take: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @indirect_enum_load_take : $@convention(thin) @async <T> (@in_guaranteed MyEnum<T>) -> () {
+bb0(%0 : $*MyEnum<T>):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %1 = alloc_stack $MyEnum<T>
+  copy_addr %0 to [init] %1
+  switch_enum_addr %1, case #MyEnum.some!enumelt: bb1, default bb2
+
+bb1:
+  %2 = unchecked_take_enum_data_addr %1, #MyEnum.some!enumelt
+  %3 = load [take] %2
+  %4 = project_box %3, 0
+  %5 = load_borrow %4
+  %6 = copy_value %5
+  debug_value [trace] %5
+  %7 = move_value [var_decl] %6
+  debug_value %5, let, name "x"
+  destroy_value %7
+  end_borrow %5
+  destroy_value %3
+  dealloc_stack %1
+  br bb3
+
+bb2:
+  destroy_addr %1
+  dealloc_stack %1
+  br bb3
+
+bb3:
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on alloc_stack_inline_array_sendable: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: no][is_sendable: yes][region_value_kind: disconnected].
+// CHECK:     Rep Value: %2 = vector_base_addr %1
+// CHECK: end running test 1 of 1 on alloc_stack_inline_array_sendable: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @alloc_stack_inline_array_sendable : $@convention(thin) () -> () {
+bb0:
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %0 = alloc_stack $InlineArray<1, UInt8>
+  %1 = struct_element_addr %0: $*InlineArray<1, UInt8>, #InlineArray._storage
+  %2 = vector_base_addr %1 : $*Builtin.FixedArray<1, UInt8>
+  %3 = integer_literal $Builtin.Int8, 0
+  %4 = struct $UInt8 (%3)
+  store %4 to [trivial] %2
+  %6 = load [trivial] %0
+  dealloc_stack %0
+  debug_value [trace] %2
+
+  %7 = tuple ()
+  return %7 : $()
+}
+
+// CHECK-LABEL: begin running test 1 of 1 on alloc_stack_inline_array_nonsendable: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+// CHECK: TrackableValue. State: TrackableValueState[id: 0][is_no_alias: yes][is_sendable: no][region_value_kind: disconnected].
+// CHECK:     Rep Value: %1 = alloc_stack $InlineArray
+// CHECK: end running test 1 of 1 on alloc_stack_inline_array_nonsendable: sil_regionanalysis_underlying_tracked_value with: @trace[0]
+sil [ossa] @alloc_stack_inline_array_nonsendable : $@convention(thin) (@owned NonSendableKlass) -> () {
+bb0(%arg : @owned $NonSendableKlass):
+  specify_test "sil_regionanalysis_underlying_tracked_value @trace[0]"
+  %0 = alloc_stack $InlineArray<1, NonSendableKlass>
+  %1 = struct_element_addr %0: $*InlineArray<1, NonSendableKlass>, #InlineArray._storage
+  %2 = vector_base_addr %1 : $*Builtin.FixedArray<1, NonSendableKlass>
+  store %arg to [init] %2
+  %6 = load [take] %0
+  destroy_value %6
+  dealloc_stack %0
+  debug_value [trace] %2
+
+  %7 = tuple ()
+  return %7 : $()
+}
diff --git a/test/Concurrency/require-explicit-sendable.swift b/test/Concurrency/require-explicit-sendable.swift
index 13426728946e7..4ddfd6c1f5765 100644
--- a/test/Concurrency/require-explicit-sendable.swift
+++ b/test/Concurrency/require-explicit-sendable.swift
@@ -1,7 +1,5 @@
 // RUN: %target-swift-frontend -require-explicit-sendable -strict-concurrency=complete %s -emit-sil -o /dev/null -verify
-// RUN: %target-swift-frontend -require-explicit-sendable -strict-concurrency=complete %s -emit-sil -o /dev/null -verify -enable-upcoming-feature RegionBasedIsolation
 
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 public protocol P { }
 
@@ -13,7 +11,6 @@ public struct S1 { // expected-warning{{public struct 'S1' does not specify whet
 
 class C { }
 
-// expected-note@+2{{add '@unchecked Sendable' conformance to struct 'S2' if this type manually implements concurrency safety}}{{18-18=: @unchecked Sendable}}
 // expected-note@+1{{make struct 'S2' explicitly non-Sendable to suppress this warning}}{{+2:2-2=\n\n@available(*, unavailable)\nextension S2: Sendable { \}\n}}
 public struct S2 { // expected-warning{{public struct 'S2' does not specify whether it is 'Sendable' or not}}
   var c: C
@@ -25,7 +22,6 @@ final public class C1: P { // expected-warning{{public class 'C1' does not speci
   let str: String = ""
 }
 
-// expected-note@+2{{add '@unchecked Sendable' conformance to class 'C2' if this type manually implements concurrency safety}}{{17-17=: @unchecked Sendable}}
 // expected-note@+1{{make class 'C2' explicitly non-Sendable to suppress this warning}}{{+2:2-2=\n\n@available(*, unavailable)\nextension C2: Sendable { \}\n}}
 public class C2 { // expected-warning{{public class 'C2' does not specify whether it is 'Sendable' or not}}
   var str: String = ""
@@ -37,7 +33,6 @@ public struct S3<T> { // expected-warning{{public generic struct 'S3' does not s
   var t: T
 }
 
-// expected-note@+2{{add '@unchecked Sendable' conformance to generic struct 'S4' if this type manually implements concurrency safety}}{{+3:2-2=\n\nextension S4: @unchecked Sendable where T: Sendable { \}\n}}
 // expected-note@+1{{make generic struct 'S4' explicitly non-Sendable to suppress this warning}}{{+3:2-2=\n\n@available(*, unavailable)\nextension S4: Sendable { \}\n}}
 public struct S4<T> { // expected-warning{{public generic struct 'S4' does not specify whether it is 'Sendable' or not}}
   var t: T
@@ -92,13 +87,12 @@ public struct S9<T: P2 & Hashable> {
 }
 
 public struct S10 { // expected-warning{{public struct 'S10' does not specify whether it is 'Sendable' or not}}
-  // expected-note@-1{{add '@unchecked Sendable' conformance to struct 'S10' if this type manually implements concurrency safety}}
-  // expected-note@-2{{make struct 'S10' explicitly non-Sendable to suppress this warning}}
+  // expected-note@-1{{make struct 'S10' explicitly non-Sendable to suppress this warning}}
   var s7: S7
 }
 
 struct S11: Sendable {
-  var s7: S7 // expected-warning{{stored property 's7' of 'Sendable'-conforming struct 'S11' has non-sendable type 'S7'}}
+  var s7: S7 // expected-warning{{stored property 's7' of 'Sendable'-conforming struct 'S11' has non-Sendable type 'S7'}}
 }
 
 @_nonSendable public struct S12 { }
diff --git a/test/Concurrency/sendable_associated_type.swift b/test/Concurrency/sendable_associated_type.swift
index c42d9300d92e7..a7c17242b035a 100644
--- a/test/Concurrency/sendable_associated_type.swift
+++ b/test/Concurrency/sendable_associated_type.swift
@@ -1,8 +1,6 @@
 // RUN: %target-swift-frontend -strict-concurrency=complete -emit-sil -o /dev/null %s -verify
-// RUN: %target-swift-frontend -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation -emit-sil -o /dev/null %s -verify
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 class C1 { } // expected-note{{class 'C1' does not conform to the 'Sendable' protocol}}
 @_nonSendable class C2 { } // expected-note{{conformance of 'C2' to 'Sendable' has been explicitly marked unavailable here}}
diff --git a/test/Concurrency/sendable_checking.swift b/test/Concurrency/sendable_checking.swift
index a8d4837c2d2e5..f9ccdc4616887 100644
--- a/test/Concurrency/sendable_checking.swift
+++ b/test/Concurrency/sendable_checking.swift
@@ -1,9 +1,11 @@
-// RUN: %target-swift-frontend -target %target-swift-5.0-abi-triple -verify -strict-concurrency=targeted -verify-additional-prefix targeted- -emit-sil -o /dev/null %s
-// RUN: %target-swift-frontend -target %target-swift-5.0-abi-triple -verify -strict-concurrency=complete -verify-additional-prefix tns- -verify-additional-prefix complete-and-tns- -emit-sil -o /dev/null %s
+// RUN: %target-swift-frontend -target %target-swift-5.0-abi-triple -verify -verify-ignore-unrelated -verify-additional-prefix targeted-and-ni- -strict-concurrency=targeted -verify-additional-prefix targeted- -emit-sil -o /dev/null %s
+// RUN: %target-swift-frontend -target %target-swift-5.0-abi-triple -verify -verify-ignore-unrelated -strict-concurrency=complete -verify-additional-prefix tns-ni- -verify-additional-prefix tns- -emit-sil -o /dev/null %s -swift-version 5 -verify-additional-prefix targeted-and-ni-
+// RUN: %target-swift-frontend -target %target-swift-5.0-abi-triple -verify -verify-ignore-unrelated -strict-concurrency=complete -verify-additional-prefix tns-ni-ns- -verify-additional-prefix tns- -emit-sil -o /dev/null %s -enable-upcoming-feature NonisolatedNonsendingByDefault -swift-version 5 -DNONISOLATEDNONSENDING
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
 // REQUIRES: OS=macosx
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 @available(SwiftStdlib 5.1, *)
 struct NS1 { }
@@ -15,7 +17,7 @@ extension NS1: Sendable { }
 
 @available(SwiftStdlib 5.1, *)
 struct NS2 { // expected-note {{consider making struct 'NS2' conform to the 'Sendable' protocol}}
-  // expected-complete-and-tns-note @-1 {{consider making struct 'NS2' conform to the 'Sendable' protocol}}
+  // expected-tns-note @-1 {{consider making struct 'NS2' conform to the 'Sendable' protocol}}
   var ns1: NS1
 }
 
@@ -27,7 +29,7 @@ extension NS3: Sendable { }
 
 @available(SwiftStdlib 5.1, *)
 class NS4 { } // expected-note {{class 'NS4' does not conform to the 'Sendable' protocol}}
-// expected-complete-and-tns-note @-1 {{class 'NS4' does not conform to the 'Sendable' protocol}}
+// expected-tns-note @-1 {{class 'NS4' does not conform to the 'Sendable' protocol}}
 
 @available(SwiftStdlib 5.1, *)
 func acceptCV<T: Sendable>(_: T) { }
@@ -38,30 +40,30 @@ func acceptSendableFn(_: @Sendable @escaping () -> Void) { }
 func testCV(
   ns1: NS1, ns1array: [NS1], ns2: NS2, ns3: NS3, ns4: NS4,
   fn: @escaping () -> Void
-  // expected-note @-1 {{parameter 'fn' is implicitly non-sendable}}
+  // expected-note @-1 {{parameter 'fn' is implicitly non-Sendable}}
 ) {
   acceptCV(ns1) // expected-warning {{conformance of 'NS1' to 'Sendable' is unavailable}}
 
   acceptCV(ns1array) // expected-warning {{conformance of 'NS1' to 'Sendable' is unavailable}}
 
-  acceptCV(ns2) // expected-complete-and-tns-warning {{type 'NS2' does not conform to the 'Sendable' protocol}}
+  acceptCV(ns2) // expected-tns-warning {{type 'NS2' does not conform to the 'Sendable' protocol}}
 
   acceptCV(ns3) // expected-warning {{conformance of 'NS3' to 'Sendable' is only available in macOS 11.0 or newer}}
   // expected-note @-1 {{add 'if #available' version check}}
 
-  acceptCV(ns4) // expected-complete-and-tns-warning {{type 'NS4' does not conform to the 'Sendable' protocol}}
+  acceptCV(ns4) // expected-tns-warning {{type 'NS4' does not conform to the 'Sendable' protocol}}
 
-  acceptCV(fn) // expected-complete-and-tns-warning {{type '() -> Void' does not conform to the 'Sendable' protocol}}
-  // expected-complete-and-tns-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  acceptCV(fn) // expected-tns-warning {{type '() -> Void' does not conform to the 'Sendable' protocol}}
+  // expected-tns-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
-  acceptSendableFn(fn) // expected-warning{{passing non-sendable parameter 'fn' to function expecting a @Sendable closure}}
+  acceptSendableFn(fn) // expected-warning{{passing non-Sendable parameter 'fn' to function expecting a '@Sendable' closure}}
 }
 
 @available(SwiftStdlib 5.1, *)
 func testCV(
   ns1: NS1, ns1array: [NS1], ns2: NS2, ns3: NS3, ns4: NS4,
   fn: @escaping () -> Void
-  // expected-note@-1{{parameter 'fn' is implicitly non-sendable}}
+  // expected-note@-1{{parameter 'fn' is implicitly non-Sendable}}
 ) async {
   acceptCV(ns1) // expected-warning{{conformance of 'NS1' to 'Sendable' is unavailable}}
   acceptCV(ns1array) // expected-warning{{conformance of 'NS1' to 'Sendable' is unavailable}}
@@ -71,7 +73,7 @@ func testCV(
   acceptCV(ns4) // expected-warning{{type 'NS4' does not conform to the 'Sendable' protocol}}
   acceptCV(fn) // expected-warning{{type '() -> Void' does not conform to the 'Sendable' protocol}}
   // expected-note@-1{{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-  acceptSendableFn(fn) // expected-warning{{passing non-sendable parameter 'fn' to function expecting a @Sendable closure}}
+  acceptSendableFn(fn) // expected-warning{{passing non-Sendable parameter 'fn' to function expecting a '@Sendable' closure}}
 }
 
 // rdar://83942484 - spurious Sendable diagnostics
@@ -93,8 +95,8 @@ public actor MyActor: MyProto {
 
   func g(ns1: NS1) async {
     await nonisolatedAsyncFunc1(ns1)
-    // expected-tns-warning @-1 {{sending 'ns1' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'self'-isolated 'ns1' to nonisolated global function 'nonisolatedAsyncFunc1' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-tns-ni-warning @-1 {{sending 'ns1' risks causing data races}}
+    // expected-tns-ni-note @-2 {{sending 'self'-isolated 'ns1' to nonisolated global function 'nonisolatedAsyncFunc1' risks causing data races between nonisolated and 'self'-isolated uses}}
     _ = await nonisolatedAsyncFunc2()
   }
 }
@@ -144,15 +146,15 @@ protocol P {
   func foo(x : () -> ()) -> () {}
 
   func bar(x : () -> ()) -> () {}
-  // expected-warning@-1 {{non-sendable parameter type '() -> ()' cannot be sent from caller of protocol requirement 'bar(x:)' into actor-isolated implementation}}
+  // expected-warning@-1 {{non-Sendable parameter type '() -> ()' cannot be sent from caller of protocol requirement 'bar(x:)' into actor-isolated implementation}}
 
   func foo2<T>(x : T) -> () {}
 
   func bar2<T>(x : T) -> () {}
-  // expected-warning@-1 {{non-sendable parameter type 'T' cannot be sent from caller of protocol requirement 'bar2(x:)' into actor-isolated implementation}}
+  // expected-warning@-1 {{non-Sendable parameter type 'T' cannot be sent from caller of protocol requirement 'bar2(x:)' into actor-isolated implementation}}
 
   func bar3<T: Equatable>(x : T) -> () {}
-  // expected-warning@-1 {{non-sendable parameter type 'T' cannot be sent from caller of protocol requirement 'bar3(x:)' into actor-isolated implementation}}
+  // expected-warning@-1 {{non-Sendable parameter type 'T' cannot be sent from caller of protocol requirement 'bar3(x:)' into actor-isolated implementation}}
 }
 
 @available(SwiftStdlib 5.1, *)
@@ -162,18 +164,18 @@ class Super {
 
   @MainActor
   func bar (x : () -> ()) async {}
-  // expected-note@-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  // expected-targeted-and-ni-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
   @MainActor
   func foo2<T : Sendable>(x: T) async {}
 
   @MainActor
   func bar2<T>(x: T) async {}
-  // expected-note@-1 {{consider making generic parameter 'T' conform to the 'Sendable' protocol}} {{14-14=: Sendable}}
+  // expected-targeted-and-ni-note @-1 {{consider making generic parameter 'T' conform to the 'Sendable' protocol}} {{14-14=: Sendable}}
 
   @MainActor
   func bar3<T: Equatable>(x: T) async {}
-  // expected-note@-1 {{consider making generic parameter 'T' conform to the 'Sendable' protocol}} {{25-25= & Sendable}}
+  // expected-targeted-and-ni-note @-1 {{consider making generic parameter 'T' conform to the 'Sendable' protocol}} {{25-25= & Sendable}}
 }
 
 // Make sure isolation crossing overrides check sendability
@@ -182,16 +184,25 @@ class Super {
 class Sub : Super {
   override nonisolated func foo(x : () -> ()) async {}
 
+  // We do not emit an error for the override with
+  // NonisolatedNonsendingByDefault since the vtable thunk passes in MainActor
+  // so we are still in the main actor even though we are nonisolated. In the
+  // case of that being disabled, we cannot do this since we will hop off the
+  // actor.
   override nonisolated func bar(x : () -> ()) async {}
-  // expected-warning@-1 {{non-sendable parameter type '() -> ()' cannot be sent from caller of superclass instance method 'bar(x:)' into nonisolated override}}
+  // expected-targeted-and-ni-warning@-1 {{non-Sendable parameter type '() -> ()' cannot be sent from caller of superclass instance method 'bar(x:)' into nonisolated override}}
 
   override nonisolated func foo2<T>(x: T) async {}
 
+  // See comment above about why nonisolated overrides of superclass are allowed
+  // when is enabled NonisolatedNonsendingByDefault.
   override nonisolated func bar2<T>(x: T) async {}
-  // expected-warning@-1 {{non-sendable parameter type 'T' cannot be sent from caller of superclass instance method 'bar2(x:)' into nonisolated override}}
+  // expected-targeted-and-ni-warning @-1 {{non-Sendable parameter type 'T' cannot be sent from caller of superclass instance method 'bar2(x:)' into nonisolated override}}
 
+  // See comment above about why nonisolated overrides of superclass are allowed
+  // when is enabled NonisolatedNonsendingByDefault.
   override nonisolated func bar3<T>(x: T) async {}
-  // expected-warning@-1 {{non-sendable parameter type 'T' cannot be sent from caller of superclass instance method 'bar3(x:)' into nonisolated override}}
+  // expected-targeted-and-ni-warning @-1 {{non-Sendable parameter type 'T' cannot be sent from caller of superclass instance method 'bar3(x:)' into nonisolated override}}
 }
 
 @available(SwiftStdlib 5.1, *)
@@ -217,7 +228,8 @@ class SubWSafeSubscript : SuperWSafeSubscript {
 class SuperWUnsafeSubscript {
   @MainActor
   subscript<T>(x : T) -> Int {
-    // expected-note@-1 2{{consider making generic parameter 'T' conform to the 'Sendable' protocol}}
+    // expected-targeted-and-ni-note @-1 {{consider making generic parameter 'T' conform to the 'Sendable' protocol}}
+    // expected-targeted-and-ni-note @-2 {{consider making generic parameter 'T' conform to the 'Sendable' protocol}}
     get async {
       return 0
     }
@@ -226,10 +238,15 @@ class SuperWUnsafeSubscript {
 
 @available(SwiftStdlib 5.1, *)
 class SubWUnsafeSubscript : SuperWUnsafeSubscript {
+  // We do not emit an error for the override with
+  // NonisolatedNonsendingByDefault since the vtable thunk passes in MainActor
+  // so we are still in the main actor even though we are nonisolated. In the
+  // case of that being disabled, we cannot do this since we will hop off the
+  // actor.
   override nonisolated subscript<T>(x : T) -> Int {
     get async {
-      // expected-warning@-2{{non-sendable parameter type 'T' cannot be sent from caller of superclass subscript 'subscript(_:)' into nonisolated override}}
-      // expected-warning@-2{{non-sendable parameter type 'T' cannot be sent from caller of superclass getter for subscript 'subscript(_:)' into nonisolated override}}
+      // expected-targeted-and-ni-warning@-2{{non-Sendable parameter type 'T' cannot be sent from caller of superclass subscript 'subscript(_:)' into nonisolated override}}
+      // expected-targeted-and-ni-warning@-2{{non-Sendable parameter type 'T' cannot be sent from caller of superclass getter for subscript 'subscript(_:)' into nonisolated override}}
       // there really shouldn't be two warnings produced here, see rdar://110846040 (Sendable diagnostics reported twice for subscript getters)
       return 0
     }
@@ -263,7 +280,7 @@ struct CustomActor {
 final class NonSendable {
   // expected-note @-1 5 {{class 'NonSendable' does not conform to the 'Sendable' protocol}}
   // TransferNonSendable emits 3 fewer errors here.
-  // expected-complete-and-tns-note @-3 {{class 'NonSendable' does not conform to the 'Sendable' protocol}}
+  // expected-tns-note @-3 {{class 'NonSendable' does not conform to the 'Sendable' protocol}}
   var value = ""
 
   @MainActor
@@ -281,10 +298,10 @@ final class NonSendable {
     // expected-tns-note @-2 {{sending task-isolated 'self' to main actor-isolated instance method 'update()' risks causing data races between main actor-isolated and task-isolated uses}}
 
     _ = await x
-    // expected-warning@-1 {{non-sendable type 'NonSendable' cannot be sent into main actor-isolated context in call to property 'x'}}
+    // expected-warning@-1 {{non-Sendable type 'NonSendable' cannot be sent into main actor-isolated context in call to property 'x'}}
 
     _ = await self.x
-      // expected-warning@-1 {{non-sendable type 'NonSendable' cannot be sent into main actor-isolated context in call to property 'x'}}
+      // expected-warning@-1 {{non-Sendable type 'NonSendable' cannot be sent into main actor-isolated context in call to property 'x'}}
   }
 
   @MainActor
@@ -296,7 +313,7 @@ final class NonSendable {
   var z: Int { 0 }
 }
 
-// This is not an error since t.update and t.x are both main actor isolated. We
+// This is not an error since t.update and t.x are both MainActor isolated. We
 // still get the returning main actor-isolated property 'x' error though.
 @available(SwiftStdlib 5.1, *)
 func testNonSendableBaseArg() async {
@@ -306,7 +323,7 @@ func testNonSendableBaseArg() async {
   // expected-tns-note @-2 {{sending 't' to main actor-isolated instance method 'update()' risks causing data races between main actor-isolated and local nonisolated uses}}
 
   _ = await t.x
-  // expected-warning @-1 {{non-sendable type 'NonSendable' cannot be sent into main actor-isolated context in call to property 'x'}}
+  // expected-warning @-1 {{non-Sendable type 'NonSendable' cannot be sent into main actor-isolated context in call to property 'x'}}
   // expected-tns-note @-2 {{access can happen concurrently}}
 }
 
@@ -321,7 +338,7 @@ func testNonSendableBaseArg2() async {
   // expected-tns-note @-4 {{sending 't' to main actor-isolated instance method 'update()' risks causing data races between main actor-isolated and local nonisolated uses}}
 
   _ = await t.y
-  // expected-warning @-1 {{non-sendable type 'NonSendable' cannot be sent into global actor 'CustomActor'-isolated context in call to property 'y'}}
+  // expected-warning @-1 {{non-Sendable type 'NonSendable' cannot be sent into global actor 'CustomActor'-isolated context in call to property 'y'}}
   // expected-tns-note @-2 {{access can happen concurrently}}
 }
 
@@ -341,6 +358,7 @@ func testNonSendableBaseArg3() async {
 @Sendable
 func globalSendable(_ ns: NonSendable) async {}
 
+#if !NONISOLATEDNONSENDING
 @available(SwiftStdlib 5.1, *)
 @MainActor
 func callNonisolatedAsyncClosure(
@@ -348,14 +366,15 @@ func callNonisolatedAsyncClosure(
   g: (NonSendable) async -> Void
 ) async {
   await g(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending main actor-isolated 'ns' to nonisolated callee risks causing data races between nonisolated and main actor-isolated uses}}
+  // expected-tns-ni-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-tns-ni-note @-2 {{sending main actor-isolated 'ns' to nonisolated callee risks causing data races between nonisolated and main actor-isolated uses}}
 
   let f: (NonSendable) async -> () = globalSendable // okay
   await f(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending main actor-isolated 'ns' to nonisolated callee risks causing data races between nonisolated and main actor-isolated uses}}
+  // expected-tns-ni-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-tns-ni-note @-2 {{sending main actor-isolated 'ns' to nonisolated callee risks causing data races between nonisolated and main actor-isolated uses}}
 }
+#endif
 
 @available(SwiftStdlib 5.1, *)
 func testLocalCaptures() {
@@ -364,7 +383,7 @@ func testLocalCaptures() {
   @Sendable
   func a2() -> NonSendable {
     return ns
-    // expected-complete-and-tns-warning @-1 {{capture of 'ns' with non-sendable type 'NonSendable' in a '@Sendable' local function}}
+    // expected-tns-warning @-1 {{capture of 'ns' with non-Sendable type 'NonSendable' in a '@Sendable' local function}}
   }
 }
 
@@ -446,8 +465,8 @@ struct DowngradeForPreconcurrency {
     preconcurrencyContext {
       Task {
         completion()
-        // expected-warning@-1 {{capture of 'completion' with non-sendable type '@MainActor () -> Void' in a '@Sendable' closure}}
-        // expected-warning@-2 {{capture of 'completion' with non-sendable type '@MainActor () -> Void' in an isolated closure}}
+        // expected-warning@-1 {{capture of 'completion' with non-Sendable type '@MainActor () -> Void' in a '@Sendable' closure}}
+        // expected-warning@-2 {{capture of 'completion' with non-Sendable type '@MainActor () -> Void' in an isolated closure}}
         // expected-note@-3 2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
         // expected-warning@-4 {{expression is 'async' but is not marked with 'await'; this is an error in the Swift 6 language mode}}
         // expected-note@-5 {{calls to parameter 'completion' from outside of its actor context are implicitly asynchronous}}
@@ -459,9 +478,8 @@ struct DowngradeForPreconcurrency {
   func createStream() -> AsyncStream<NonSendable> {
     AsyncStream<NonSendable> {
       self.x
-      // expected-warning@-1 {{expression is 'async' but is not marked with 'await'; this is an error in the Swift 6 language mode}}
-      // expected-note@-2 {{property access is 'async'}}
-      // expected-warning@-3 {{non-sendable type 'NonSendable' of property 'x' cannot exit main actor-isolated context; this is an error in the Swift 6 language mode}}
+      // expected-warning@-1 {{main actor-isolated property 'x' cannot be accessed from outside of the actor; this is an error in the Swift 6 language mode}} {{7-7=await }}
+      // expected-warning@-2 {{non-Sendable type 'NonSendable' of property 'x' cannot exit main actor-isolated context; this is an error in the Swift 6 language mode}}
     }
   }
 }
@@ -527,3 +545,35 @@ func sendablePacks<each Element: Sendable>(
 
 @available(SwiftStdlib 5.1, *)
 func sendPack<each Element>(_: repeat each Element) async {}
+
+// rdar://153083848 - crash in `getConcurrencyFixBehavior` when member comes from a tuple
+func test(value: (_: Int, _: () -> Void)) {
+  func takesSendable(_: @Sendable () -> Void) {}
+
+  takesSendable(value.1) // Ok
+  // expected-warning@-1 {{converting non-Sendable function value to '@Sendable () -> Void' may introduce data races}}
+}
+
+// Don't forget about parameter packs -- https://github.com/swiftlang/swift/issues/82614
+
+@available(SwiftStdlib 5.1, *)
+protocol PackProto {
+  func foo<each A: Sendable>(_ a: repeat each A) async
+  func bar<each A>(_ a: repeat each A) async
+  // expected-note@-1 {{consider making generic parameter 'each A' conform to the 'Sendable' protocol}}
+}
+
+@available(SwiftStdlib 5.1, *)
+actor PackActor: PackProto {
+  func foo<each A: Sendable>(_ a: repeat each A) async {
+    for b in repeat (each a) {
+      print(b)
+    }
+  }
+  func bar<each A>(_ a: repeat each A) async {
+  // expected-warning@-1 {{non-Sendable parameter type 'repeat each A' cannot be sent from caller of protocol requirement 'bar' into actor-isolated implementation; this is an error in the Swift 6 language mode}}
+    for b in repeat (each a) {
+      print(b)
+    }
+  }
+}
diff --git a/test/Concurrency/sendable_checking_captures_swift5.swift b/test/Concurrency/sendable_checking_captures_swift5.swift
index f6bf66906bfb2..470b40607e2f9 100644
--- a/test/Concurrency/sendable_checking_captures_swift5.swift
+++ b/test/Concurrency/sendable_checking_captures_swift5.swift
@@ -9,10 +9,10 @@ var testLocalCaptures: Int {
   let ns = NonSendable()
 
   @Sendable func localFunc() -> NonSendable {
-    return ns // expected-complete-warning {{capture of 'ns' with non-sendable type 'NonSendable' in a '@Sendable' local function}}
+    return ns // expected-complete-warning {{capture of 'ns' with non-Sendable type 'NonSendable' in a '@Sendable' local function}}
   }
 
-  callee { return ns } // expected-complete-warning {{capture of 'ns' with non-sendable type 'NonSendable' in a '@Sendable' closure}}
+  callee { return ns } // expected-complete-warning {{capture of 'ns' with non-Sendable type 'NonSendable' in a '@Sendable' closure}}
 
   return 3
 }
@@ -20,7 +20,7 @@ var testLocalCaptures: Int {
 struct Bad {
   var c: Int = {
     let ns = NonSendable()
-    callee { return ns } // expected-complete-warning {{capture of 'ns' with non-sendable type 'NonSendable' in a '@Sendable' closure}}
+    callee { return ns } // expected-complete-warning {{capture of 'ns' with non-Sendable type 'NonSendable' in a '@Sendable' closure}}
     return 3
   }()
 }
@@ -40,13 +40,13 @@ do {
   withMutable { test in
     sendable {
       test.update()
-      // expected-complete-warning@-1 {{capture of 'test' with non-sendable type 'Test' in a '@Sendable' closure}}
+      // expected-complete-warning@-1 {{capture of 'test' with non-Sendable type 'Test' in a '@Sendable' closure}}
       // expected-warning@-2 {{mutable capture of 'inout' parameter 'test' is not allowed in concurrently-executing code}}
     }
 
     sendable_preconcurrency {
       test.update()
-      // expected-complete-warning@-1 {{capture of 'test' with non-sendable type 'Test' in a '@Sendable' closure}}
+      // expected-complete-warning@-1 {{capture of 'test' with non-Sendable type 'Test' in a '@Sendable' closure}}
       // expected-complete-warning@-2 {{mutable capture of 'inout' parameter 'test' is not allowed in concurrently-executing code}}
     }
   }
@@ -63,7 +63,7 @@ func testPreconcurrencyDowngrade(ns: NotSendable) {
   var x = 0
   withSendableClosure {
     _ = ns
-    // expected-complete-warning@-1 {{capture of 'ns' with non-sendable type 'NotSendable' in a '@Sendable' closure}}
+    // expected-complete-warning@-1 {{capture of 'ns' with non-Sendable type 'NotSendable' in a '@Sendable' closure}}
 
     x += 1
     // expected-complete-warning@-1 {{mutation of captured var 'x' in concurrently-executing code}}
@@ -92,5 +92,5 @@ do {
 
   let c: Class
   test(c)
-  // expected-complete-warning@-1:8 {{implicit capture of 'c' requires that 'Class' conforms to 'Sendable'; this is an error in the Swift 6 language mode}}
+  // expected-complete-warning@-1:8 {{implicit capture of 'c' requires that 'Class' conforms to 'Sendable'}}
 }
diff --git a/test/Concurrency/sendable_checking_captures_swift6.swift b/test/Concurrency/sendable_checking_captures_swift6.swift
index b40fe6a8113c5..84792cae4726c 100644
--- a/test/Concurrency/sendable_checking_captures_swift6.swift
+++ b/test/Concurrency/sendable_checking_captures_swift6.swift
@@ -8,10 +8,10 @@ var testLocalCaptures: Int {
   let ns = NonSendable()
 
   @Sendable func localFunc() -> NonSendable {
-    return ns // expected-error {{capture of 'ns' with non-sendable type 'NonSendable' in a '@Sendable' local function}}
+    return ns // expected-error {{capture of 'ns' with non-Sendable type 'NonSendable' in a '@Sendable' local function}}
   }
 
-  callee { return ns } // expected-error {{capture of 'ns' with non-sendable type 'NonSendable' in a '@Sendable' closure}}
+  callee { return ns } // expected-error {{capture of 'ns' with non-Sendable type 'NonSendable' in a '@Sendable' closure}}
 
   return 3
 }
@@ -19,7 +19,7 @@ var testLocalCaptures: Int {
 struct Bad {
   var c: Int = {
     let ns = NonSendable()
-    callee { return ns } // expected-error {{capture of 'ns' with non-sendable type 'NonSendable' in a '@Sendable' closure}}
+    callee { return ns } // expected-error {{capture of 'ns' with non-Sendable type 'NonSendable' in a '@Sendable' closure}}
     return 3
   }()
 }
@@ -39,14 +39,42 @@ do {
   withMutable { test in
     sendable {
       test.update()
-      // expected-error@-1 {{capture of 'test' with non-sendable type 'Test' in a '@Sendable' closure}}
+      // expected-error@-1 {{capture of 'test' with non-Sendable type 'Test' in a '@Sendable' closure}}
       // expected-error@-2 {{mutable capture of 'inout' parameter 'test' is not allowed in concurrently-executing code}}
     }
 
     sendable_preconcurrency {
       test.update()
-      // expected-warning@-1 {{capture of 'test' with non-sendable type 'Test' in a '@Sendable' closure}}
+      // expected-warning@-1 {{capture of 'test' with non-Sendable type 'Test' in a '@Sendable' closure}}
       // expected-warning@-2 {{mutable capture of 'inout' parameter 'test' is not allowed in concurrently-executing code}}
     }
   }
 }
+
+func use(_ closure: @autoclosure () -> Any) {
+}
+
+do {
+  class C {
+    @preconcurrency static func f(_: @escaping @Sendable () -> Void) {}
+  }
+
+  class SelfCapture { // expected-note 5 {{class 'SelfCapture' does not conform to the 'Sendable' protocol}}
+    func fooDirect() {
+      C.f {
+        use(self)
+        // expected-warning@-1 {{capture of 'self' with non-Sendable type 'SelfCapture' in a '@Sendable' closure}}
+        // expected-warning@-2 {{implicit capture of 'self' requires that 'SelfCapture' conforms to 'Sendable'}}
+      }
+    }
+
+    func fooThroughClosure() {
+      C.f {
+        { use(self) }()
+        // expected-warning@-1 {{capture of 'self' with non-Sendable type 'SelfCapture' in a '@Sendable' closure}}
+        // expected-warning@-2 {{capture of 'self' with non-Sendable type 'SelfCapture' in an isolated closure}}
+        // expected-warning@-3 {{implicit capture of 'self' requires that 'SelfCapture' conforms to 'Sendable'}}
+      }
+    }
+  }
+}
diff --git a/test/Concurrency/sendable_checking_errors.swift b/test/Concurrency/sendable_checking_errors.swift
index 9e7de8aa5546c..3bcd08fbf190c 100644
--- a/test/Concurrency/sendable_checking_errors.swift
+++ b/test/Concurrency/sendable_checking_errors.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -strict-concurrency=complete %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -strict-concurrency=complete %s
 
 // Don't test TransferNonSendable because this test will not make
 // it past Sema to the SIL pass.
diff --git a/test/Concurrency/sendable_conformance_checking.swift b/test/Concurrency/sendable_conformance_checking.swift
index 786c02cb6ac6e..d29b10072b3fb 100644
--- a/test/Concurrency/sendable_conformance_checking.swift
+++ b/test/Concurrency/sendable_conformance_checking.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -emit-sil %s -o /dev/null -verify
 // RUN: %target-swift-frontend -emit-sil %s -o /dev/null -verify -strict-concurrency=targeted
-// RUN: %target-swift-frontend -emit-sil %s -o /dev/null -verify -verify-additional-prefix complete-and-tns- -strict-concurrency=complete
-// RUN: %target-swift-frontend -emit-sil %s -o /dev/null -verify -verify-additional-prefix complete-and-tns- -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
+// RUN: %target-swift-frontend -emit-sil %s -o /dev/null -verify -verify-additional-prefix complete- -strict-concurrency=complete
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @available(SwiftStdlib 5.1, *)
 class NotSendable { // expected-note 9{{class 'NotSendable' does not conform to the 'Sendable' protocol}}
@@ -38,7 +36,7 @@ actor A2: IsolatedWithNotSendableRequirements {
   nonisolated var prop: NotSendable { NotSendable() }
 
   nonisolated func fAsync() async -> NotSendable { NotSendable() }
-  // expected-warning@-1{{non-sendable type 'NotSendable' cannot be returned from nonisolated implementation to caller of protocol requirement 'fAsync()'}}
+  // expected-warning@-1{{non-Sendable type 'NotSendable' cannot be returned from nonisolated implementation to caller of protocol requirement 'fAsync()'}}
 }
 
 @available(SwiftStdlib 5.1, *)
@@ -51,9 +49,9 @@ protocol AsyncProtocolWithNotSendable {
 // actor's domain.
 @available(SwiftStdlib 5.1, *)
 actor A3: AsyncProtocolWithNotSendable {
-  func f() async -> NotSendable { NotSendable() } // expected-warning{{non-sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'f()'}}
+  func f() async -> NotSendable { NotSendable() } // expected-warning{{non-Sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'f()'}}
 
-  var prop: NotSendable { // expected-warning{{non-sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'prop'}}
+  var prop: NotSendable { // expected-warning{{non-Sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'prop'}}
     get async {
       NotSendable()
     }
@@ -64,9 +62,9 @@ actor A3: AsyncProtocolWithNotSendable {
 // actor's domain.
 @available(SwiftStdlib 5.1, *)
 actor A4: AsyncProtocolWithNotSendable {
-  func f() -> NotSendable { NotSendable() } // expected-warning{{non-sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'f()'}}
+  func f() -> NotSendable { NotSendable() } // expected-warning{{non-Sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'f()'}}
 
-  var prop: NotSendable { // expected-warning{{non-sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'prop'}}
+  var prop: NotSendable { // expected-warning{{non-Sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'prop'}}
     get {
       NotSendable()
     }
@@ -109,9 +107,9 @@ protocol AsyncThrowingProtocolWithNotSendable {
 // actor's domain.
 @available(SwiftStdlib 5.1, *)
 actor A7: AsyncThrowingProtocolWithNotSendable {
-  func f() async -> NotSendable { NotSendable() } // expected-warning{{non-sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'f()'}}
+  func f() async -> NotSendable { NotSendable() } // expected-warning{{non-Sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'f()'}}
 
-  var prop: NotSendable { // expected-warning{{non-sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'prop'}}
+  var prop: NotSendable { // expected-warning{{non-Sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'prop'}}
     get async {
       NotSendable()
     }
@@ -122,9 +120,9 @@ actor A7: AsyncThrowingProtocolWithNotSendable {
 // actor's domain.
 @available(SwiftStdlib 5.1, *)
 actor A8: AsyncThrowingProtocolWithNotSendable {
-  func f() -> NotSendable { NotSendable() } // expected-warning{{non-sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'f()'}}
+  func f() -> NotSendable { NotSendable() } // expected-warning{{non-Sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'f()'}}
 
-  var prop: NotSendable { // expected-warning{{non-sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'prop'}}
+  var prop: NotSendable { // expected-warning{{non-Sendable type 'NotSendable' cannot be returned from actor-isolated implementation to caller of protocol requirement 'prop'}}
     get {
       NotSendable()
     }
@@ -158,11 +156,11 @@ actor A10: AsyncThrowingProtocolWithNotSendable {
 }
 
 // rdar://86653457 - Crash due to missing Sendable conformances.
-// expected-warning @+1 {{non-final class 'Klass' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+// expected-warning @+1 {{non-final class 'Klass' cannot conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode}}
 class Klass<Output: Sendable>: Sendable {}
-// expected-complete-and-tns-warning @+1 {{type 'S' does not conform to the 'Sendable' protocol}}
+// expected-complete-warning @+1 {{type 'S' does not conform to the 'Sendable' protocol}}
 final class SubKlass: Klass<[S]> {}
-// expected-complete-and-tns-note @+1 {{consider making struct 'S' conform to the 'Sendable' protocol}}
+// expected-complete-note @+1 {{consider making struct 'S' conform to the 'Sendable' protocol}}
 public struct S {}
 
 // rdar://88700507 - redundant conformance of @MainActor-isolated subclass to 'Sendable'
@@ -184,7 +182,7 @@ extension MultiConformance: @unchecked Sendable {} // expected-warning {{redunda
 
 @available(SwiftStdlib 5.1, *)
 actor MyActor {
-  // expected-warning@+1 {{non-final class 'Nested' cannot conform to 'Sendable'; use '@unchecked Sendable'; this is an error in the Swift 6 language mode}}
+  // expected-warning@+1 {{non-final class 'Nested' cannot conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode}}
   class Nested: Sendable {}
 }
 
@@ -207,14 +205,14 @@ public struct TestSendableWitnesses2 : NoSendableReqs {
 
 // @preconcurrency attributes to make it akin to an imported Obj-C API
 @preconcurrency @MainActor public protocol EscapingSendableProtocol {
-  // expected-complete-and-tns-note @+1 {{protocol requires function 'f(handler:)' with type '(@escaping @MainActor @Sendable (Int) -> Void) -> ()'}}
+  // expected-complete-note @+1 {{protocol requires function 'f(handler:)' with type '(@escaping @MainActor @Sendable (Int) -> Void) -> ()'}}
   @preconcurrency func f(handler: @escaping @MainActor @Sendable (Int) -> Void)
 }
 
 // TODO: The following error should actually be a warning.
-// expected-complete-and-tns-error @+2 {{type 'TestEscapingOnly' does not conform to protocol 'EscapingSendableProtocol'}}
-// expected-complete-and-tns-note @+1 {{add stubs for conformance}}
+// expected-complete-error @+2 {{type 'TestEscapingOnly' does not conform to protocol 'EscapingSendableProtocol'}}
+// expected-complete-note @+1 {{add stubs for conformance}}
 class TestEscapingOnly: EscapingSendableProtocol {
-    // expected-complete-and-tns-note @+1 {{candidate has non-matching type '(@escaping (Int) -> Void) -> ()'}}
+    // expected-complete-note @+1 {{candidate has non-matching type '(@escaping (Int) -> Void) -> ()'}}
     func f(handler: @escaping (Int) -> Void) {}
 }
diff --git a/test/Concurrency/sendable_conformance_checking_skip_sending.swift b/test/Concurrency/sendable_conformance_checking_skip_sending.swift
new file mode 100644
index 0000000000000..ae97baa994a3e
--- /dev/null
+++ b/test/Concurrency/sendable_conformance_checking_skip_sending.swift
@@ -0,0 +1,89 @@
+// RUN: %target-typecheck-verify-swift -swift-version 6
+
+// https://github.com/swiftlang/swift/issues/76710
+
+class NonSendableKlass1 {}
+
+protocol P1 {
+  func bar(_ a: sending NonSendableKlass1) async -> sending NonSendableKlass1
+}
+
+@MainActor
+class P1Class: P1 {
+  func bar(_ a: sending NonSendableKlass1) async -> sending NonSendableKlass1 { a }
+}
+
+class NonSendableKlass2 {}
+// expected-note@-1 2{{class 'NonSendableKlass2' does not conform to the 'Sendable' protocol}}
+
+protocol P2 {
+  func bar(_ a: NonSendableKlass2) async -> NonSendableKlass2
+}
+
+@MainActor
+class P2Class: P2 {
+  func bar(_ a: NonSendableKlass2) async -> NonSendableKlass2 { a }
+  // expected-error@-1 {{non-Sendable type 'NonSendableKlass2' cannot be returned from main actor-isolated implementation to caller of protocol requirement 'bar'}}
+  // expected-error@-2 {{non-Sendable parameter type 'NonSendableKlass2' cannot be sent from caller of protocol requirement 'bar' into main actor-isolated implementation}}
+}
+
+class NonSendableKlass3 {}
+
+protocol P3 {
+  func bar(_ a: sending NonSendableKlass3) async -> sending NonSendableKlass3
+}
+
+actor P3Actor: P3 {
+  func bar(_ a: sending NonSendableKlass3) async -> sending NonSendableKlass3 { NonSendableKlass3() }
+}
+
+class NonSendableKlass4 {}
+// expected-note@-1 2{{class 'NonSendableKlass4' does not conform to the 'Sendable' protocol}}
+
+protocol P4 {
+  func bar(_ a: NonSendableKlass4) async -> NonSendableKlass4
+}
+
+actor P4Actor: P4 {
+  func bar(_ a: NonSendableKlass4) async -> NonSendableKlass4 { NonSendableKlass4() }
+  // expected-error@-1 {{non-Sendable type 'NonSendableKlass4' cannot be returned from actor-isolated implementation to caller of protocol requirement 'bar'}}
+  // expected-error@-2 {{non-Sendable parameter type 'NonSendableKlass4' cannot be sent from caller of protocol requirement 'bar' into actor-isolated implementation}}
+}
+
+class NonSendableKlass5 {}
+// expected-note@-1 {{class 'NonSendableKlass5' does not conform to the 'Sendable' protocol}}
+
+
+protocol P5 {
+  func bar(_ a: sending NonSendableKlass5, _ b: NonSendableKlass5) async -> sending NonSendableKlass5
+}
+
+@MainActor
+class P5Class: P5 {
+  func bar(_ a: sending NonSendableKlass5, _ b: NonSendableKlass5) async -> sending NonSendableKlass5 { a }
+  // expected-error@-1 {{non-Sendable parameter type 'NonSendableKlass5' cannot be sent from caller of protocol requirement 'bar' into main actor-isolated implementation}}
+}
+
+class NonSendableKlass6 {}
+
+protocol P6 {
+  func bar(_ a: sending NonSendableKlass6, _ b: sending NonSendableKlass6) async -> sending NonSendableKlass6
+}
+
+@MainActor
+class P6Class: P6 {
+  func bar(_ a: sending NonSendableKlass6, _ b: sending NonSendableKlass6) async -> sending NonSendableKlass6 { a }
+}
+
+class NonSendableKlass7 {}
+
+protocol P7 {
+  subscript(_: sending NonSendableKlass7) -> sending NonSendableKlass7 { get async }
+}
+
+@MainActor
+struct S: P7 {
+  subscript(_: sending NonSendableKlass7) -> sending NonSendableKlass7 {
+    get async { NonSendableKlass7() }
+  }
+}
diff --git a/test/Concurrency/sendable_cycle.swift b/test/Concurrency/sendable_cycle.swift
index b49d6612620f6..a11eb14d84819 100644
--- a/test/Concurrency/sendable_cycle.swift
+++ b/test/Concurrency/sendable_cycle.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend %S/Inputs/sendable_cycle_other.swift  -target %target-swift-5.1-abi-triple %s -verify -emit-sil -o /dev/null
 // RUN: %target-swift-frontend %S/Inputs/sendable_cycle_other.swift  -target %target-swift-5.1-abi-triple %s -verify -emit-sil -o /dev/null -strict-concurrency=targeted
 // RUN: %target-swift-frontend %S/Inputs/sendable_cycle_other.swift  -target %target-swift-5.1-abi-triple %s -verify -emit-sil -o /dev/null -strict-concurrency=complete -verify-additional-prefix complete-
-// RUN: %target-swift-frontend %S/Inputs/sendable_cycle_other.swift  -target %target-swift-5.1-abi-triple %s -verify -emit-sil -o /dev/null -strict-concurrency=complete -verify-additional-prefix complete- -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 struct Bar { // expected-note*{{consider making struct 'Bar' conform to the 'Sendable' protocol}}
   lazy var foo = { // expected-error {{escaping closure captures mutating 'self' parameter}}
diff --git a/test/Concurrency/sendable_existentials.swift b/test/Concurrency/sendable_existentials.swift
index 9e8fb4128867a..1231bfe7f5bcc 100644
--- a/test/Concurrency/sendable_existentials.swift
+++ b/test/Concurrency/sendable_existentials.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -strict-concurrency=targeted -emit-sil -o /dev/null %s -verify
-// RUN: %target-swift-frontend -strict-concurrency=complete -verify-additional-prefix complete-and-tns- -verify-additional-prefix complete- -emit-sil -o /dev/null %s -verify
-// RUN: %target-swift-frontend -strict-concurrency=complete -verify-additional-prefix complete-and-tns- -emit-sil -o /dev/null %s -verify -enable-upcoming-feature RegionBasedIsolation
+// RUN: %target-swift-frontend -strict-concurrency=complete -verify-additional-prefix complete- -emit-sil -o /dev/null %s -verify
 
 // REQUIRES: concurrency
 // REQUIRES: OS=macosx
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @preconcurrency func send(_: Sendable) { }
 func sendOpt(_: Sendable?) { }
@@ -37,22 +35,22 @@ func testE(a: Any, aOpt: Any?) async {
 }
 
 func testESilently(a: Any, aOpt: Any?) {
-  send(a) // expected-complete-and-tns-warning {{'Any' does not conform to the 'Sendable' protocol}}
-  sendOpt(a) // expected-complete-and-tns-warning {{'Any' does not conform to the 'Sendable' protocol}}
-  sendOpt(aOpt) // expected-complete-and-tns-warning {{'Any' does not conform to the 'Sendable' protocol}}
+  send(a) // expected-complete-warning {{'Any' does not conform to the 'Sendable' protocol}}
+  sendOpt(a) // expected-complete-warning {{'Any' does not conform to the 'Sendable' protocol}}
+  sendOpt(aOpt) // expected-complete-warning {{'Any' does not conform to the 'Sendable' protocol}}
 
-  let _: E = .something(a) // expected-complete-and-tns-warning {{'Any' does not conform to the 'Sendable' protocol}}
-  _ = E.something(a) // expected-complete-and-tns-warning {{'Any' does not conform to the 'Sendable' protocol}}
+  let _: E = .something(a) // expected-complete-warning {{'Any' does not conform to the 'Sendable' protocol}}
+  _ = E.something(a) // expected-complete-warning {{'Any' does not conform to the 'Sendable' protocol}}
 
   var sendable: Sendable
-  sendable = a // expected-complete-and-tns-warning {{'Any' does not conform to the 'Sendable' protocol}}
+  sendable = a // expected-complete-warning {{'Any' does not conform to the 'Sendable' protocol}}
 
   var arrayOfSendable: [Sendable]
-  arrayOfSendable = [a, a] // expected-complete-and-tns-warning 2{{'Any' does not conform to the 'Sendable' protocol}}
+  arrayOfSendable = [a, a] // expected-complete-warning 2{{'Any' does not conform to the 'Sendable' protocol}}
 
   func localFunc() { }
-  sendable = localFunc // expected-complete-and-tns-warning {{'() -> ()' does not conform to the 'Sendable' protocol}}
-  // expected-complete-and-tns-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  sendable = localFunc // expected-complete-warning {{'() -> ()' does not conform to the 'Sendable' protocol}}
+  // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
   _ = sendable
   _ = arrayOfSendable
 }
diff --git a/test/Concurrency/sendable_functions.swift b/test/Concurrency/sendable_functions.swift
index a753153f2424f..a462f366b084d 100644
--- a/test/Concurrency/sendable_functions.swift
+++ b/test/Concurrency/sendable_functions.swift
@@ -1,9 +1,7 @@
 // RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=complete
 // RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=complete
-// RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @Sendable func globalFunc() { }
 
diff --git a/test/Concurrency/sendable_keypaths.swift b/test/Concurrency/sendable_keypaths.swift
index 47232b3d94f67..6db444cbbe0ed 100644
--- a/test/Concurrency/sendable_keypaths.swift
+++ b/test/Concurrency/sendable_keypaths.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-upcoming-feature InferSendableFromCaptures -strict-concurrency=complete -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-upcoming-feature InferSendableFromCaptures -strict-concurrency=complete -enable-upcoming-feature GlobalActorIsolatedTypesUsability
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
@@ -22,7 +22,7 @@ class NonSendable : Hashable {
 final class CondSendable<T> : Hashable {
   init(_: T) {}
   init(_: Int) {}
-  init(_: T, other: T = 42) {}
+  init<U>(_: T, other: U = 42) {}
   init<Q>(_: [Q] = []) {}
 
   static func == (x: CondSendable, y: CondSendable) -> Bool { false }
@@ -61,13 +61,13 @@ do {
 
   let _: KeyPath<K, Bool> = \.[NonSendable()] // ok
   let _: KeyPath<K, Bool> & Sendable = \.[NonSendable()] // expected-warning {{type 'KeyPath<K, Bool>' does not conform to the 'Sendable' protocol}}
-  let _: KeyPath<K, Int> & Sendable = \.[42, NonSendable(data: [-1, 0, 1])] // expected-warning {{type 'ReferenceWritableKeyPath<K, Int>' does not conform to the 'Sendable' protocol}}
+  let _: KeyPath<K, Int> & Sendable = \.[42, NonSendable(data: [-1, 0, 1])] // expected-warning {{type 'KeyPath<K, Int>' does not conform to the 'Sendable' protocol}}
   let _: KeyPath<K, Int> & Sendable = \.[42, -1] // Ok
 
   test(nonSendableKP) // expected-warning {{type 'KeyPath<K, Bool>' does not conform to the 'Sendable' protocol}}
 }
 
-// Test using sendable and non-sendable key paths.
+// Test using sendable and non-Sendable key paths.
 do {
   class V {
     var i: Int = 0
@@ -97,16 +97,16 @@ do {
   testSendableFn(v: v, \.[42]) // Ok
 
   testSendableKP(v: v, \.[NonSendable()]) // expected-warning {{type 'KeyPath<V, Int>' does not conform to the 'Sendable' protocol}}
-  testSendableFn(v: v, \.[NonSendable()]) // expected-warning {{converting non-sendable function value to '@Sendable (V) -> Int' may introduce data races}}
+  testSendableFn(v: v, \.[NonSendable()]) // expected-warning {{converting non-Sendable function value to '@Sendable (V) -> Int' may introduce data races}}
 
   testNonSendableKP(v: v, \.[NonSendable()]) // Ok
   testNonSendableFn(v: v, \.[NonSendable()]) // Ok
 
   let _: @Sendable (V) -> Int = \.[NonSendable()]
-  // expected-warning@-1 {{converting non-sendable function value to '@Sendable (V) -> Int' may introduce data races}}
+  // expected-warning@-1 {{converting non-Sendable function value to '@Sendable (V) -> Int' may introduce data races}}
 
   let _: KeyPath<V, Int> & Sendable = \.[42, CondSendable(NonSendable(data: [1, 2, 3]))]
-  // expected-warning@-1 {{type 'ReferenceWritableKeyPath<V, Int>' does not conform to the 'Sendable' protocol}}
+  // expected-warning@-1 {{type 'KeyPath<V, Int>' does not conform to the 'Sendable' protocol}}
   let _: KeyPath<V, Int> & Sendable = \.[42, CondSendable(42)] // Ok
 
   struct Root {
@@ -114,17 +114,17 @@ do {
   }
 
   testSendableKP(v: v, \.[42, CondSendable(NonSendable(data: [1, 2, 3]))])
-  // expected-warning@-1 {{type 'ReferenceWritableKeyPath<V, Int>' does not conform to the 'Sendable' protocol}}
+  // expected-warning@-1 {{type 'KeyPath<V, Int>' does not conform to the 'Sendable' protocol}}
   testSendableFn(v: v, \.[42, CondSendable(NonSendable(data: [1, 2, 3]))])
-  // expected-warning@-1 {{converting non-sendable function value to '@Sendable (V) -> Int' may introduce data races}}
+  // expected-warning@-1 {{converting non-Sendable function value to '@Sendable (V) -> Int' may introduce data races}}
   testSendableKP(v: v, \.[42, CondSendable(42)]) // Ok
 
   let nonSendable = NonSendable()
   testSendableKP(v: v, \.[42, CondSendable(nonSendable)])
-  // expected-warning@-1 {{type 'ReferenceWritableKeyPath<V, Int>' does not conform to the 'Sendable' protocol}}
+  // expected-warning@-1 {{type 'KeyPath<V, Int>' does not conform to the 'Sendable' protocol}}
 
   testSendableFn(v: v, \.[42, CondSendable(nonSendable)])
-  // expected-warning@-1 {{converting non-sendable function value to '@Sendable (V) -> Int' may introduce data races}}
+  // expected-warning@-1 {{converting non-Sendable function value to '@Sendable (V) -> Int' may introduce data races}}
 }
 
 // @dynamicMemberLookup with Sendable requirement
@@ -141,7 +141,7 @@ do {
   _ = Test(obj: "Hello").utf8.count // Ok
 }
 
-// Global actor isolated properties.
+// global-actor-isolated properties.
 func testGlobalActorIsolatedReferences() {
   @MainActor struct Isolated {
     var data: Int = 42
@@ -224,7 +224,7 @@ do {
 
   // TODO(rdar://125948508): This shouldn't be ambiguous (@Sendable version should be preferred)
   func test() -> KeyPath<String, Int> {
-    true ? kp() : kp() // expected-error {{type of expression is ambiguous without a type annotation}}
+    true ? kp() : kp() // expected-error {{failed to produce diagnostic for expression}}
   }
 
   func forward<T>(_ v: T) -> T { v }
@@ -249,7 +249,7 @@ do {
 
   // TODO(rdar://125948508): This shouldn't be ambiguous (@Sendable version should be preferred)
   func fnRet(cond: Bool) -> () -> Void {
-    cond ? Test.fn : Test.otherFn // expected-error {{type of expression is ambiguous without a type annotation}}
+    cond ? Test.fn : Test.otherFn // expected-error {{failed to produce diagnostic for expression}}
   }
 
   func forward<T>(_: T) -> T {
@@ -258,3 +258,33 @@ do {
   // TODO(rdar://125948508): This shouldn't be ambiguous (@Sendable version should be preferred)
   let _: () -> Void = forward(Test.fn) // expected-error {{conflicting arguments to generic parameter 'T' ('@Sendable () -> ()' vs. '() -> Void')}}
 }
+
+// https://github.com/swiftlang/swift/issues/77105
+do {
+  @dynamicMemberLookup
+  struct S<T> {
+    subscript<U>(dynamicMember keyPath: KeyPath<T, U> & Sendable) -> U {
+      fatalError()
+    }
+  }
+
+  struct Foo {
+    subscript<T>(bar bar: T) -> Int { 42 }
+  }
+
+  func test(s: S<Foo>) {
+    _ = s[bar: NonSendable()]
+    // expected-warning@-1 {{type 'KeyPath<Foo, Int>' does not conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode}}
+  }
+}
+
+public final class TestSetterRef {
+  public internal(set) var v: Int = 0 // expected-note {{setter for property 'v' is not '@usableFromInline' or public}}
+
+  public func test1(_ kp: KeyPath<TestSetterRef, Int> = \.v) {} // Ok
+  public func test2(_ kp: KeyPath<TestSetterRef, Int> = \TestSetterRef.v) {} // Ok
+  public func test3(_ kp: KeyPath<TestSetterRef, Int> & Sendable = \.v) {} // Ok
+
+  public func test_err(_ kp: WritableKeyPath<TestSetterRef, Int> = \.v) {}
+  // expected-warning@-1 {{setter for property 'v' is internal and should not be referenced from a default argument value}}
+}
diff --git a/test/Concurrency/sendable_metatype.swift b/test/Concurrency/sendable_metatype.swift
index a21366ac6f0f2..83dd82f110509 100644
--- a/test/Concurrency/sendable_metatype.swift
+++ b/test/Concurrency/sendable_metatype.swift
@@ -1,8 +1,9 @@
-// RUN: %target-typecheck-verify-swift -swift-version 6 -enable-experimental-feature IsolatedConformances -emit-sil -o /dev/null
+// RUN: %target-typecheck-verify-swift -swift-version 6 -emit-sil -o /dev/null
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_IsolatedConformances
 
+protocol P {
+}
 
 protocol Q {
   static func g()
@@ -18,29 +19,35 @@ func acceptMetaOnMainActor<T>(_: T.Type) { }
 // -------------------------------------------------------------------------
 nonisolated func staticCallThroughMetaSmuggled<T: Q>(_: T.Type) {
   let x: Q.Type = T.self
-  Task.detached { // expected-error{{risks causing data races}}
+  Task.detached { // expected-warning{{risks causing data races}}
     x.g() // expected-note{{closure captures 'x' which is accessible to code in the current task}}
   }
 }
 
 nonisolated func passMetaSmuggled<T: Q>(_: T.Type) {
   let x: Q.Type = T.self
-  Task.detached { // expected-error{{risks causing data races}}
+  Task.detached { // expected-warning{{risks causing data races}}
     acceptMeta(x) // expected-note{{closure captures 'x' which is accessible to code in the current task}}
   }
 }
 
 nonisolated func passMetaSmuggledAny<T: Q>(_: T.Type) {
   let x: Any.Type = T.self
-  Task.detached { // expected-error{{risks causing data races}}
-    acceptMeta(x) // expected-note{{closure captures 'x' which is accessible to code in the current task}}
+  Task.detached {
+    acceptMeta(x)
+  }
+}
+
+nonisolated func captureThroughMetaValMoReqs<T>(_: T.Type) {
+  let x = T.self
+  Task.detached {
+    _ = x
   }
 }
 
 nonisolated func passToMainActorSmuggledAny<T: Q>(_: T.Type) async {
   let x: Any.Type = T.self
-  await acceptMetaOnMainActor(x) // expected-error{{sending value of non-Sendable type '(Any).Type' risks causing data races}}
-  // expected-note@-1{{sending task-isolated value of non-Sendable type '(Any).Type' to main actor-isolated global function}}
+  await acceptMetaOnMainActor(x)
 }
 
 // -------------------------------------------------------------------------
@@ -70,9 +77,220 @@ nonisolated func passSendableToMainActorSmuggledAny<T: Sendable>(_: T.Type) asyn
 // -------------------------------------------------------------------------
 // Existential opening
 // -------------------------------------------------------------------------
-nonisolated func passMetaSmuggledAnyFromExistential(_ qT: Q.Type) {
-  let x: Any.Type = qT
-  Task.detached { // expected-error{{risks causing data races}}
+nonisolated func passMetaSmuggledAnyFromExistential(_ pqT: (P & Q).Type) {
+  let x: P.Type = pqT
+  Task.detached { // expected-warning{{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
     acceptMeta(x) // expected-note{{closure captures 'x' which is accessible to code in the current task}}
   }
 }
+
+
+func testSendableMetatypeDowngrades() {
+  @preconcurrency
+  func acceptsSendableMetatype<T: SendableMetatype>(_: T.Type) {
+  }
+
+  func testWarning<T>(t: T.Type) { // expected-note {{consider making generic parameter 'T' conform to the 'SendableMetatype' protocol}} {{21-21=: SendableMetatype}}
+    acceptsSendableMetatype(t) // expected-warning {{type 'T' does not conform to the 'SendableMetatype' protocol}}
+  }
+
+  func testWarning<T: P>(t: T.Type) { // expected-note {{consider making generic parameter 'T' conform to the 'SendableMetatype' protocol}} {{24-24= & SendableMetatype}}
+    acceptsSendableMetatype(t) // expected-warning {{type 'T' does not conform to the 'SendableMetatype' protocol}}
+  }
+}
+
+// -------------------------------------------------------------------------
+// Conformance isolation for sending parameters
+// -------------------------------------------------------------------------
+
+protocol R: SendableMetatype { }
+
+@MainActor
+struct S: @MainActor P, R { }
+
+@MainActor
+class SC: @MainActor P, R { }
+
+func acceptSendingP(_ s: sending any P) { }
+func acceptSendingAnyObjectP(_ s: sending AnyObject & P) { }
+
+func acceptSendingR(_ s: sending any R) { }
+func acceptSendingAnyObjectR(_ s: sending AnyObject & R) { }
+
+@MainActor func passSendingExistential<T: P, U: AnyObject & P , V: R, W: AnyObject & R>(
+  t: sending T, u: sending U, v: sending V, w: sending W
+) {
+  acceptSendingP(S()) // expected-warning{{sending value of non-Sendable type 'S' risks causing data races}}
+  // expected-note@-1{{Passing main actor-isolated value of non-Sendable type 'S' as a 'sending' parameter to global function 'acceptSendingP' risks causing races}}
+  // expected-note@-2{{isolated conformance to protocol 'P' can be introduced here}}
+  acceptSendingP(SC()) // expected-warning{{sending value of non-Sendable type 'SC'}}
+  // expected-note@-1{{Passing main actor-isolated value of non-Sendable type 'SC' as a 'sending' parameter to global function 'acceptSendingP' risks causing races}}' risks causing data races}}
+  // expected-note@-2{{isolated conformance to protocol 'P' can be introduced here}}
+  acceptSendingAnyObjectP(SC()) // expected-warning{{sending value of non-Sendable type 'SC' risks causing data races}}
+  // expected-note@-1{{Passing main actor-isolated value of non-Sendable type 'SC' as a 'sending' parameter to global function 'acceptSendingAnyObjectP' risks causing races}}' risks causing data races}}
+  // expected-note@-2{{isolated conformance to protocol 'P' can be introduced here}}
+  acceptSendingP(t) // expected-warning{{sending 't' risks causing data races}}
+  // expected-note@-1{{task-isolated 't' is passed as a 'sending' parameter; Uses in callee may race with later task-isolated uses}}
+  // expected-note@-2{{isolated conformance to protocol 'P' can be introduced he}}
+  acceptSendingAnyObjectP(u) // expected-warning{{sending value of non-Sendable type 'U' risks causing data races}}
+  // expected-note@-1{{task-isolated value of non-Sendable type 'U'}}
+  // expected-note@-2{{isolated conformance to protocol 'P' can be introduced here}}
+  // All of these are okay, because there are no isolated conformances to R.
+  acceptSendingR(S())
+  acceptSendingR(SC())
+  acceptSendingAnyObjectR(SC())
+  acceptSendingR(v)
+  acceptSendingAnyObjectR(w)
+}
+
+func dynamicCastingExistential(
+  _ s1: sending Any,
+  _ s2: sending Any
+) {
+  if let s1p = s1 as? any P { // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+    acceptSendingP(s1p) // expected-warning{{sending 's1p' risks causing data races}}
+    // expected-note@-1{{task-isolated 's1p' is passed as a 'sending' parameter; Uses in callee may race with later task-isolated uses}}
+  } else {
+    print(s1)
+  }
+
+  if let s2p = s2 as? any AnyObject & P { // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+    acceptSendingAnyObjectP(s2p) // expected-warning{{sending 's2p' risks causing data races}}
+    // expected-note@-1{{task-isolated 's2p' is passed as a 'sending' parameter; Uses in callee may race with later task-isolated uses}}
+  } else {
+    print(s2)
+  }
+}
+
+// @concurrent functions cannot pick up any isolated conformances dynamically,
+// because they aren't on an actor. Make sure we don't complain.
+@concurrent func dynamicCastingExistentialConcurrent(
+  _ s1: sending Any,
+  _ s2: sending Any
+) async {
+  if let s1p = s1 as? any P {
+    acceptSendingP(s1p)
+  } else {
+    print(s1)
+  }
+
+  if let s2p = s2 as? any AnyObject & P {
+    acceptSendingAnyObjectP(s2p)
+  } else {
+    print(s2)
+  }
+}
+
+func dynamicCastingGeneric(
+  _ s1: sending some Any,
+  _ s2: sending some Any
+) {
+  if let s1p = s1 as? any P { // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+    acceptSendingP(s1p) // expected-warning{{sending 's1p' risks causing data races}}
+    // expected-note@-1{{task-isolated 's1p' is passed as a 'sending' parameter; Uses in callee may race with later task-isolated uses}}
+  } else {
+    print(s1)
+  }
+
+  if let s2p = s2 as? any AnyObject & P { // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+    acceptSendingAnyObjectP(s2p) // expected-warning{{sending 's2p' risks causing data races}}
+    // expected-note@-1{{task-isolated 's2p' is passed as a 'sending' parameter; Uses in callee may race with later task-isolated uses}}
+  } else {
+    print(s2)
+  }
+}
+
+@MainActor func dynamicCastingExistentialGood(
+  _ s1: sending Any,
+  _ s2: sending Any
+) {
+  if let s1p = s1 as? any R {
+    acceptSendingR(s1p)
+  } else {
+    print(s1)
+  }
+
+  if let s2p = s2 as? any AnyObject & R {
+    acceptSendingAnyObjectR(s2p)
+  } else {
+    print(s2)
+  }
+}
+
+@MainActor func dynamicCastingGenericGood(
+  _ s1: sending some Any,
+  _ s2: sending some Any
+) {
+  if let s1p = s1 as? any R {
+    acceptSendingR(s1p)
+  } else {
+    print(s1)
+  }
+
+  if let s2p = s2 as? any AnyObject & R {
+    acceptSendingAnyObjectR(s2p)
+  } else {
+    print(s2)
+  }
+}
+
+func forceCastingExistential(
+  _ s1: sending Any,
+  _ s2: sending AnyObject
+) {
+  let s1p = s1 as! any P // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+  acceptSendingP(s1p) // expected-warning{{sending 's1p' risks causing data races}}
+  // expected-note@-1{{task-isolated 's1p' is passed as a 'sending' parameter; Uses in callee may race with later task-isolated uses}}
+
+  let s2p = s2 as! any AnyObject & P // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+  acceptSendingAnyObjectP(s2p) // expected-warning{{sending 's2p' risks causing data races}}
+  // expected-note@-1{{task-isolated 's2p' is passed as a 'sending' parameter; Uses in callee may race with later task-isolated uses}}
+}
+
+@MainActor func forceCastingExistentialGood(
+  _ s1: sending Any,
+  _ s2: sending AnyObject
+) {
+  let s1p = s1 as! any R
+  acceptSendingR(s1p) // okay
+
+  let s2p = s2 as! any AnyObject & R
+  acceptSendingAnyObjectR(s2p) // okay
+}
+
+func forceCastingGeneric(
+  _ s1: sending some Any,
+  _ s2: sending some AnyObject
+) {
+  let s1p = s1 as! any P // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+  acceptSendingP(s1p) // expected-warning{{sending 's1p' risks causing data races}}
+  // expected-note@-1{{task-isolated 's1p' is passed as a 'sending' parameter; Uses in callee may race with later task-isolated uses}}
+
+  let s2p = s2 as! any AnyObject & P // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+  acceptSendingAnyObjectP(s2p) // expected-warning{{sending 's2p' risks causing data races}}
+  // expected-note@-1{{task-isolated 's2p' is passed as a 'sending' parameter; Uses in callee may race with later task-isolated uses}}
+}
+
+@MainActor func forceCastingGenericMainActor(
+  _ s1: sending some Any,
+  _ s2: sending some AnyObject
+) {
+  let s1p = s1 as! any P // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+  acceptSendingP(s1p) // expected-warning{{sending 's1p' risks causing data races}}
+  // expected-note@-1{{main actor-isolated 's1p' is passed as a 'sending' parameter; Uses in callee may race with later main actor-isolated uses}}
+
+  let s2p = s2 as! any AnyObject & P // expected-note{{isolated conformance to protocol 'P' can be introduced here}}
+  acceptSendingAnyObjectP(s2p) // expected-warning{{sending 's2p' risks causing data races}}
+  // expected-note@-1{{main actor-isolated 's2p' is passed as a 'sending' parameter; Uses in callee may race with later main actor-isolated uses}}
+}
+
+@MainActor func forceCastingGenericGood(
+  _ s1: sending some Any,
+  _ s2: sending some AnyObject
+) {
+  let s1p = s1 as! any R
+  acceptSendingR(s1p) // okay
+
+  let s2p = s2 as! any AnyObject & R
+  acceptSendingAnyObjectR(s2p) // okay
+}
diff --git a/test/Concurrency/sendable_metatype_swift5.swift b/test/Concurrency/sendable_metatype_swift5.swift
new file mode 100644
index 0000000000000..5fbbb088b4589
--- /dev/null
+++ b/test/Concurrency/sendable_metatype_swift5.swift
@@ -0,0 +1,13 @@
+// RUN: %target-typecheck-verify-swift -swift-version 5
+
+// REQUIRES: concurrency
+
+protocol P {
+  static func doSomething()
+}
+
+func doSomethingStatic<T: P>(_: T.Type) {
+  Task { @concurrent in
+    T.doSomething()
+  }
+}
diff --git a/test/Concurrency/sendable_metatype_typecheck.swift b/test/Concurrency/sendable_metatype_typecheck.swift
index 6ba6def4956c3..89d57582588fc 100644
--- a/test/Concurrency/sendable_metatype_typecheck.swift
+++ b/test/Concurrency/sendable_metatype_typecheck.swift
@@ -1,40 +1,55 @@
-// RUN: %target-typecheck-verify-swift -swift-version 6 -enable-experimental-feature IsolatedConformances
+// RUN: %target-typecheck-verify-swift -swift-version 6
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_IsolatedConformances
 
-// This test checks for typecheck-only diagnostics involving non-sendable
+// This test checks for typecheck-only diagnostics involving non-Sendable
 // metatypes.
 
 protocol Q {
   static func g()
 }
 
+
+// Sendability of existential metatypes
+fileprivate nonisolated let anyObjectArray: [AnyClass] = []
+
+func testSendableExistential() {
+  _ = anyObjectArray
+}
+
+
 nonisolated func acceptMeta<T>(_: T.Type) { }
 
 nonisolated func staticCallThroughMetaVal<T: Q>(_: T.Type) {
-  let x = T.self // expected-error{{capture of non-sendable type 'T.Type' in an isolated closure}}
+  let x = T.self
+  Task.detached {
+    x.g() // expected-warning{{capture of non-Sendable type 'T.Type' in an isolated closure}}
+  }
+}
+
+nonisolated func captureThroughMetaValMoReqs<T>(_: T.Type) {
+  let x = T.self
   Task.detached {
-    x.g() // expected-error{{capture of non-sendable type 'T.Type' in an isolated closure}}
+    _ = x
   }
 }
 
 nonisolated func passMetaVal<T: Q>(_: T.Type) {
-  let x = T.self // expected-error{{capture of non-sendable type 'T.Type' in an isolated closure}}
+  let x = T.self
   Task.detached {
-    acceptMeta(x) // expected-error{{capture of non-sendable type}}
+    acceptMeta(x) // expected-warning{{capture of non-Sendable type}}
   }
 }
 
 nonisolated func staticCallThroughMeta<T: Q>(_: T.Type) {
   Task.detached {
-    T.g() // expected-error{{capture of non-sendable type}}
+    T.g() // expected-warning{{capture of non-Sendable type}}
   }
 }
 
 nonisolated func passMeta<T: Q>(_: T.Type) {
   Task.detached {
-    acceptMeta(T.self) // expected-error{{capture of non-sendable type 'T.Type' in an isolated closure}}
+    acceptMeta(T.self) // expected-warning{{capture of non-Sendable type 'T.Type' in an isolated closure}}
   }
 }
 
@@ -72,3 +87,121 @@ nonisolated func passMetaWithMetaSendableVal<T: SendableMetatype & Q>(_: T.Type)
     x.g() // okay, because T is Sendable implies T.Type: Sendable
   }
 }
+
+struct GenericThingy<Element> {
+  func searchMe(_: (Element, Element) -> Bool) { }
+
+  func test() where Element: Comparable {
+    // Ensure that this we infer a non-@Sendable function type for Comparable.<
+    searchMe(<)
+
+    let _: (Element, Element) -> Bool = (>)
+    let _: @Sendable (Element, Element) -> Bool = (>) // expected-error{{converting non-Sendable function value to '@Sendable (Element, Element) -> Bool' may introduce data races}}
+  }
+}
+
+extension Int: Q {
+  static func g() { }
+}
+
+extension String: Q {
+  static func g() { }
+}
+
+class Holder: @unchecked Sendable {
+  // expected-note@+3{{disable concurrency-safety checks if accesses are protected by an external synchronization mechanism}}
+  // expected-note@+2{{add '@MainActor' to make static property 'globalExistentialThing' part of global actor 'MainActor'}}
+  // expected-warning@+1{{static property 'globalExistentialThing' is not concurrency-safe because non-'Sendable' type 'Dictionary<Int, any Q.Type>' may have shared mutable state}}
+  static let globalExistentialThing: Dictionary<Int, Q.Type> = [
+    1: Int.self,
+    2: String.self,
+  ]
+}
+
+enum E: Sendable {
+case q(Q.Type, Int) // expected-warning{{associated value 'q' of 'Sendable'-conforming enum 'E' contains non-Sendable type 'any Q.Type'}}
+}
+
+struct S: Sendable {
+  var tuple: ([Q.Type], Int) // expected-warning{{stored property 'tuple' of 'Sendable'-conforming struct 'S' contains non-Sendable type 'any Q.Type'}}
+}
+
+extension Q {
+  static func h() -> Self { }
+}
+
+extension Array: Q where Element: Q {
+  static func g() { }
+}
+
+struct GenericS<T> { }
+
+extension GenericS: Q where T: Q {
+  static func g() { }
+}
+
+extension GenericS: Sendable where T: Sendable { }
+
+final class TestStaticMembers<T> {
+  init(_: T) {
+    let _: @Sendable () -> GenericS<Int> = GenericS.h // Ok
+  }
+}
+
+// Downgrade use of static member references on non-Sendable base to a warning until next major mode to maintain source compatibility.
+do {
+  struct S<U> {
+    static func test(_: U, _: U) -> Bool { false }
+  }
+
+  func compute<T>(_: S<T>, _: @escaping @Sendable (T, T) -> Bool) {}
+
+  func test<T: Comparable>(s: S<T>) {
+    compute(s, >) // expected-warning {{converting non-Sendable function value to '@Sendable (T, T) -> Bool' may introduce data races}}
+    compute(s, S.test) // expected-warning {{capture of non-Sendable type 'T.Type' in an isolated closure}}
+  }
+}
+
+infix operator <=> : ComparisonPrecedence
+
+struct TestUnapplied<U> : Comparable {
+  static func <(_: TestUnapplied<U>, _: TestUnapplied<U>) -> Bool { false }
+}
+
+extension TestUnapplied {
+  static func <=>(_: Self, _: @escaping @Sendable (U, U) -> Bool) {}
+}
+
+func testUnappliedWithOpetator<T: Comparable>(v: TestUnapplied<T>) {
+  v<=>(>) // expected-error {{converting non-Sendable function value to '@Sendable (T, T) -> Bool' may introduce data races}}
+}
+
+protocol P {}
+
+func acceptClosure(_: () -> Void) {}
+
+@MainActor
+func f<T: P>(_: T.Type) {
+  acceptClosure {
+    Task {
+      _ = T.self // okay to capture T.Type in this closure.
+    }
+  }
+}
+
+func sendableSequence<S: AsyncSequence & Sendable>(_ s: S) throws {
+  Task.detached {
+    for try await i in s {
+      print(i)
+    }
+  }
+}
+
+func nonSendableSequence<S: AsyncSequence>(_ s: S) throws {
+  Task.detached {
+    for try await i in s { // expected-warning{{capture of non-Sendable type 'S.AsyncIterator.Type' in an isolated closure}}
+      // expected-warning@-1{{capture of non-Sendable type 'S.Type' in an isolated closure}}
+      print(i)
+    }
+  }
+}
diff --git a/test/Concurrency/sendable_methods.swift b/test/Concurrency/sendable_methods.swift
index 3e3313ce11c7b..75038c79da216 100644
--- a/test/Concurrency/sendable_methods.swift
+++ b/test/Concurrency/sendable_methods.swift
@@ -10,7 +10,7 @@ func outer() {
     func nonSendable() {}
 
     let _ : @Sendable () -> Void = sendable
-    let _ : @Sendable () -> Void = nonSendable // expected-warning{{converting non-sendable function value to '@Sendable () -> Void' may introduce data races}}
+    let _ : @Sendable () -> Void = nonSendable // expected-warning{{converting non-Sendable function value to '@Sendable () -> Void' may introduce data races}}
 }
 
 
@@ -118,7 +118,7 @@ h(GenericQ<NonSendable>().f) // ok
 h(GenericS(NonSendable()).f) // ok
 h(GenericS<Int>().f)
 h(GenericS(1).f)
-h(NonSendable().f) // expected-warning{{converting non-sendable function value to '@Sendable () -> Void' may introduce data races}}
+h(NonSendable().f) // expected-warning{{converting non-Sendable function value to '@Sendable () -> Void' may introduce data races}}
 
 func executeAsTask (_ f: @escaping  @Sendable () -> Void) {
   Task {
@@ -128,7 +128,7 @@ func executeAsTask (_ f: @escaping  @Sendable () -> Void) {
 executeAsTask(S().f)
 executeAsTask(C().f)
 executeAsTask(E().f)
-executeAsTask(NonSendable().f) // expected-warning{{converting non-sendable function value to '@Sendable () -> Void' may introduce data races}}
+executeAsTask(NonSendable().f) // expected-warning{{converting non-Sendable function value to '@Sendable () -> Void' may introduce data races}}
 
 do {
   let f = S.f
@@ -148,9 +148,9 @@ var partialClass : @Sendable () -> Void = C().f
 var partialEnum : @Sendable () -> Void = E().f
 
 // Reassign
-partialClass = NonSendable().f // expected-warning{{converting non-sendable function value to '@Sendable () -> Void' may introduce data races}}
-partialStruct = NonSendable().f // expected-warning{{converting non-sendable function value to '@Sendable () -> Void' may introduce data races}}
-partialEnum = NonSendable().f // expected-warning{{converting non-sendable function value to '@Sendable () -> Void' may introduce data races}}
+partialClass = NonSendable().f // expected-warning{{converting non-Sendable function value to '@Sendable () -> Void' may introduce data races}}
+partialStruct = NonSendable().f // expected-warning{{converting non-Sendable function value to '@Sendable () -> Void' may introduce data races}}
+partialEnum = NonSendable().f // expected-warning{{converting non-Sendable function value to '@Sendable () -> Void' may introduce data races}}
 
 // Static Functions 
 struct World {
@@ -309,7 +309,7 @@ do {
   let _: @Sendable (S) -> @Sendable () -> Void = S.foo // Ok
 
   let classFn = NonSendable.f(NonSendable())
-  bar(classFn) // expected-warning {{converting non-sendable function value to '@Sendable () -> Void' may introduce data races}}
+  bar(classFn) // expected-warning {{converting non-Sendable function value to '@Sendable () -> Void' may introduce data races}}
 
   let _: @Sendable (NonSendable) -> () -> Void = NonSendable.f // Ok
 
diff --git a/test/Concurrency/sendable_obc_protocol.swift b/test/Concurrency/sendable_obc_protocol.swift
index c055535ec5376..b86cc27e16798 100644
--- a/test/Concurrency/sendable_obc_protocol.swift
+++ b/test/Concurrency/sendable_obc_protocol.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil %s -verify -parse-as-library -o /dev/null
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil %s -verify -parse-as-library -o /dev/null -strict-concurrency=targeted
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil %s -verify -parse-as-library -o /dev/null -strict-concurrency=complete
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil %s -verify -parse-as-library -o /dev/null -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: objc_interop
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 import Foundation
 
diff --git a/test/Concurrency/sendable_objc_attr_in_type_context_swift5.swift b/test/Concurrency/sendable_objc_attr_in_type_context_swift5.swift
index 7e9d6c7c0f6ec..19ff5312c4737 100644
--- a/test/Concurrency/sendable_objc_attr_in_type_context_swift5.swift
+++ b/test/Concurrency/sendable_objc_attr_in_type_context_swift5.swift
@@ -6,7 +6,7 @@
 // RUN:   -import-objc-header %t/src/Test.h \
 // RUN:   -swift-version 5 \
 // RUN:   -enable-experimental-feature SendableCompletionHandlers \
-// RUN:   -module-name main -I %t -verify
+// RUN:   -module-name main -I %t -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 // REQUIRES: swift_feature_SendableCompletionHandlers
@@ -211,3 +211,7 @@ extension TestDR {
   @_dynamicReplacement(for: test(completion:))
   func __replaceObjCFunc(_: @escaping () -> Void) {} // Ok
 }
+
+@MainActor
+class InvalidIsolated: NSObject, @MainActor P {}
+// expected-warning@-1 {{cannot form main actor-isolated conformance of 'InvalidIsolated' to SendableMetatype-inheriting protocol 'P'}}
diff --git a/test/Concurrency/sendable_objc_attr_in_type_context_swift5_strict.swift b/test/Concurrency/sendable_objc_attr_in_type_context_swift5_strict.swift
index 3764ab0976962..832e7a6ab2532 100644
--- a/test/Concurrency/sendable_objc_attr_in_type_context_swift5_strict.swift
+++ b/test/Concurrency/sendable_objc_attr_in_type_context_swift5_strict.swift
@@ -7,7 +7,7 @@
 // RUN:   -swift-version 5 \
 // RUN:   -strict-concurrency=complete \
 // RUN:   -enable-experimental-feature SendableCompletionHandlers \
-// RUN:   -module-name main -I %t -verify
+// RUN:   -module-name main -I %t -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 // REQUIRES: swift_feature_SendableCompletionHandlers
diff --git a/test/Concurrency/sendable_objc_attr_in_type_context_swift6.swift b/test/Concurrency/sendable_objc_attr_in_type_context_swift6.swift
index 29750fae6bc36..6a9afa3734e68 100644
--- a/test/Concurrency/sendable_objc_attr_in_type_context_swift6.swift
+++ b/test/Concurrency/sendable_objc_attr_in_type_context_swift6.swift
@@ -6,7 +6,7 @@
 // RUN:   -import-objc-header %t/src/Test.h \
 // RUN:   -swift-version 6 \
 // RUN:   -enable-experimental-feature SendableCompletionHandlers \
-// RUN:   -module-name main -I %t -verify
+// RUN:   -module-name main -I %t -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 // REQUIRES: swift_feature_SendableCompletionHandlers
@@ -86,6 +86,10 @@ void doSomethingConcurrently(__attribute__((noescape)) void SWIFT_SENDABLE (^blo
 -(void) testWithCompletion: (void (^)(void)) completion;
 @end
 
+@interface TestSelfCapture : NSObject
++ (void)doWithCompletion:(void(^)(void)) completion;
+@end
+
 #pragma clang assume_nonnull end
 
 //--- main.swift
@@ -219,3 +223,25 @@ extension TestDR {
   @_dynamicReplacement(for: test(completion:))
   func __replaceObjCFunc(_: @escaping () -> Void) {} // Ok
 }
+
+class SelfCapture { // expected-note 5 {{class 'SelfCapture' does not conform to the 'Sendable' protocol}}
+  static func use(_ closure: @autoclosure () -> Any) {
+  }
+  
+  func testDirect() {
+    TestSelfCapture.do {
+      Self.use(self)
+      // expected-warning@-1 {{capture of 'self' with non-Sendable type 'SelfCapture' in a '@Sendable' closure}}
+      // expected-warning@-2 {{implicit capture of 'self' requires that 'SelfCapture' conforms to 'Sendable'}}
+    }
+  }
+
+  func testThroughClosure() {
+    TestSelfCapture.do {
+      let _ = { Self.use(self) }()
+      // expected-warning@-1 {{capture of 'self' with non-Sendable type 'SelfCapture' in a '@Sendable' closure}}
+      // expected-warning@-2 {{capture of 'self' with non-Sendable type 'SelfCapture' in an isolated closure}}
+      // expected-warning@-3 {{implicit capture of 'self' requires that 'SelfCapture' conforms to 'Sendable'}}
+    }
+  }
+}
diff --git a/test/Concurrency/sendable_objc_protocol_attr.swift b/test/Concurrency/sendable_objc_protocol_attr.swift
index 15527a7a91a55..2b94fc80fa1eb 100644
--- a/test/Concurrency/sendable_objc_protocol_attr.swift
+++ b/test/Concurrency/sendable_objc_protocol_attr.swift
@@ -41,7 +41,7 @@ extension MyObjCProtocol {
 }
 
 class K : NSObject, MyObjCProtocol {
-  // expected-warning@-1 {{non-final class 'K' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+  // expected-warning@-1 {{non-final class 'K' cannot conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode}}
   let test: String = "k"
 }
 
@@ -50,7 +50,7 @@ class UncheckedK : NSObject, MyObjCProtocol, @unchecked Sendable { // ok
 }
 
 class KRefined : NSObject, MyRefinedObjCProtocol {
-  // expected-warning@-1 {{non-final class 'KRefined' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+  // expected-warning@-1 {{non-final class 'KRefined' cannot conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode}}
   let test: String = "refined"
 }
 
@@ -76,7 +76,7 @@ do {
   }
 
   class C : A, MyObjCProtocol {
-    // expected-warning@-1 {{non-final class 'C' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+    // expected-warning@-1 {{non-final class 'C' cannot conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode}}
     // expected-warning@-2 {{'Sendable' class 'C' cannot inherit from another class other than 'NSObject'}}
     let test: String = "c"
   }
diff --git a/test/Concurrency/sendable_override_checking.swift b/test/Concurrency/sendable_override_checking.swift
index 71916d2c74320..faea70493ce77 100644
--- a/test/Concurrency/sendable_override_checking.swift
+++ b/test/Concurrency/sendable_override_checking.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend -verify -emit-sil -o /dev/null %s
 // RUN: %target-swift-frontend -verify -emit-sil -o /dev/null %s -strict-concurrency=targeted
 // RUN: %target-swift-frontend -verify -emit-sil -o /dev/null %s -strict-concurrency=complete
-// RUN: %target-swift-frontend -verify -emit-sil -o /dev/null %s -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @available(SwiftStdlib 5.1, *)
 class NotSendable { // expected-note 2{{class 'NotSendable' does not conform to the 'Sendable' protocol}}
@@ -24,10 +22,10 @@ class Super {
 @available(SwiftStdlib 5.1, *)
 class Sub: Super {
   @MainActor override func f(_: NotSendable) async { }
-  // expected-warning@-1{{non-sendable parameter type 'NotSendable' cannot be sent from caller of superclass instance method 'f' into main actor-isolated override}}
+  // expected-warning@-1{{non-Sendable parameter type 'NotSendable' cannot be sent from caller of superclass instance method 'f' into main actor-isolated override}}
 
   nonisolated override func g1(_: NotSendable) { } // okay, synchronous
 
   nonisolated override func g2(_: NotSendable) async { }
-  // expected-warning@-1{{non-sendable parameter type 'NotSendable' cannot be sent from caller of superclass instance method 'g2' into nonisolated override}}
+  // expected-warning@-1{{non-Sendable parameter type 'NotSendable' cannot be sent from caller of superclass instance method 'g2' into nonisolated override}}
 }
diff --git a/test/Concurrency/sendable_preconcurrency.swift b/test/Concurrency/sendable_preconcurrency.swift
index 4b23171987eaf..9bf3ec85a2e50 100644
--- a/test/Concurrency/sendable_preconcurrency.swift
+++ b/test/Concurrency/sendable_preconcurrency.swift
@@ -3,8 +3,8 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/StrictModule.swiftmodule -module-name StrictModule -swift-version 6 %S/Inputs/StrictModule.swift
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/NonStrictModule.swiftmodule -module-name NonStrictModule %S/Inputs/NonStrictModule.swift
 
-// RUN: %target-swift-frontend -strict-concurrency=targeted -disable-availability-checking -I %t %s -o /dev/null -verify -emit-sil
-// RUN: %target-swift-frontend -disable-availability-checking -I %t %s -o /dev/null -verify -emit-sil -strict-concurrency=complete -verify-additional-prefix tns-
+// RUN: %target-swift-frontend -strict-concurrency=targeted -disable-availability-checking -I %t %s -o /dev/null -verify -verify-ignore-unrelated -emit-sil
+// RUN: %target-swift-frontend -disable-availability-checking -I %t %s -o /dev/null -verify -verify-ignore-unrelated -emit-sil -strict-concurrency=complete -verify-additional-prefix tns-
 
 // REQUIRES: concurrency
 
@@ -23,7 +23,7 @@ struct MyType {
 
 struct MyType2: Sendable {
   var nsc: NonStrictClass // no warning; @preconcurrency suppressed it
-  var ns: NS // expected-warning{{stored property 'ns' of 'Sendable'-conforming struct 'MyType2' has non-sendable type 'NS'}}
+  var ns: NS // expected-warning{{stored property 'ns' of 'Sendable'-conforming struct 'MyType2' has non-Sendable type 'NS'}}
 }
 
 struct MyType3 {
diff --git a/test/Concurrency/sendable_preconcurrency_unused.swift b/test/Concurrency/sendable_preconcurrency_unused.swift
index 53b6c9811d5c6..db724fcb15e81 100644
--- a/test/Concurrency/sendable_preconcurrency_unused.swift
+++ b/test/Concurrency/sendable_preconcurrency_unused.swift
@@ -4,10 +4,8 @@
 // RUN: %target-swift-frontend -disable-availability-checking -I %t -verify -emit-sil %s -o /dev/null
 // RUN: %target-swift-frontend -disable-availability-checking -I %t -verify -emit-sil %s -o /dev/null -strict-concurrency=targeted
 // RUN: %target-swift-frontend -disable-availability-checking -I %t -verify -emit-sil %s -o /dev/null -strict-concurrency=complete
-// RUN: %target-swift-frontend -disable-availability-checking -I %t -verify -emit-sil %s -o /dev/null -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @preconcurrency import NonStrictModule
 
diff --git a/test/Concurrency/sendable_without_preconcurrency_2.swift b/test/Concurrency/sendable_without_preconcurrency_2.swift
index 35ddfcbe4da36..17ccfef40d175 100644
--- a/test/Concurrency/sendable_without_preconcurrency_2.swift
+++ b/test/Concurrency/sendable_without_preconcurrency_2.swift
@@ -3,10 +3,10 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/StrictModule.swiftmodule -module-name StrictModule -swift-version 6 %S/Inputs/StrictModule.swift
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/NonStrictModule.swiftmodule -module-name NonStrictModule %S/Inputs/NonStrictModule.swift
 
-// RUN: %target-swift-frontend -strict-concurrency=minimal -disable-availability-checking -I %t %s -verify -emit-sil -o /dev/null
-// RUN: %target-swift-frontend -strict-concurrency=targeted -verify-additional-prefix targeted-complete- -disable-availability-checking -I %t %s -verify -emit-sil -o /dev/null
+// RUN: %target-swift-frontend -strict-concurrency=minimal -disable-availability-checking -I %t %s -verify -verify-ignore-unrelated -emit-sil -o /dev/null
+// RUN: %target-swift-frontend -strict-concurrency=targeted -verify-additional-prefix targeted-complete- -disable-availability-checking -I %t %s -verify -verify-ignore-unrelated -emit-sil -o /dev/null
 
-// RUN: %target-swift-frontend -strict-concurrency=complete -verify-additional-prefix targeted-complete- -verify-additional-prefix complete- -disable-availability-checking -I %t %s -verify -emit-sil -o /dev/null -verify-additional-prefix tns-
+// RUN: %target-swift-frontend -strict-concurrency=complete -verify-additional-prefix targeted-complete- -verify-additional-prefix complete- -disable-availability-checking -I %t %s -verify -verify-ignore-unrelated -emit-sil -o /dev/null -verify-additional-prefix tns-
 
 // REQUIRES: concurrency
 
@@ -24,8 +24,8 @@ struct MyType {
 }
 
 struct MyType2: Sendable {
-  var nsc: NonStrictClass // expected-warning{{stored property 'nsc' of 'Sendable'-conforming struct 'MyType2' has non-sendable type 'NonStrictClass'}}
-  var ns: NS // expected-warning{{stored property 'ns' of 'Sendable'-conforming struct 'MyType2' has non-sendable type 'NS'}}
+  var nsc: NonStrictClass // expected-warning{{stored property 'nsc' of 'Sendable'-conforming struct 'MyType2' has non-Sendable type 'NonStrictClass'}}
+  var ns: NS // expected-warning{{stored property 'ns' of 'Sendable'-conforming struct 'MyType2' has non-Sendable type 'NS'}}
 }
 
 func testA(ns: NS, mt: MyType, mt2: MyType2, sc: StrictClass, nsc: NonStrictClass) async {
diff --git a/test/Concurrency/sendable_witness_check_delayed.swift b/test/Concurrency/sendable_witness_check_delayed.swift
index daf4bdc047742..e4e6a56b11e54 100644
--- a/test/Concurrency/sendable_witness_check_delayed.swift
+++ b/test/Concurrency/sendable_witness_check_delayed.swift
@@ -1,9 +1,7 @@
 // RUN: %target-swift-frontend -o /dev/null -emit-sil %s -verify
 // RUN: %target-swift-frontend -o /dev/null -emit-sil %s -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend -o /dev/null -emit-sil %s -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -o /dev/null -emit-sil %s -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // This triggers a conformance check with SuppressDiagnostics=true.
 let x = S().f {}
diff --git a/test/Concurrency/sending_conditional_suppression.swift b/test/Concurrency/sending_conditional_suppression.swift
index 4c86ecfad1411..861ed22494d4d 100644
--- a/test/Concurrency/sending_conditional_suppression.swift
+++ b/test/Concurrency/sending_conditional_suppression.swift
@@ -1,222 +1,107 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-upcoming-feature SendingArgsAndResults -swift-version 5 -enable-library-evolution -module-name test -emit-module -o %t/test.swiftmodule -emit-module-interface-path - -target %target-swift-5.1-abi-triple -Xllvm -swift-ast-printer-number-suppression-checks %s | %FileCheck %s
+// RUN: %target-swift-frontend -enable-upcoming-feature SendingArgsAndResults -swift-version 5 -enable-library-evolution -module-name test -emit-module -o %t/test.swiftmodule -emit-module-interface-path - -target %target-swift-5.1-abi-triple %s | %FileCheck %s
 
 // REQUIRES: swift_feature_SendingArgsAndResults
 // REQUIRES: asserts
 
 public class NonSendableKlass {}
 
-// CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
-// CHECK-NEXT: public func transferArgTest(_ x: sending test.NonSendableKlass)
-// CHECK-NEXT: #else
-// When we suppress, we preserve +1 by marking the parameter as __owned. Otherwise, we
-// be breaking ABI.
-// CHECK-NEXT: public func transferArgTest(_ x: __owned test.NonSendableKlass)
-// CHECK-NEXT: #endif
+// CHECK: public func transferArgTest(_ x: sending test.NonSendableKlass)
 public func transferArgTest(_ x: sending NonSendableKlass) {}
 
-// CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
 // CHECK-NEXT: public func transferResultTest() -> sending test.NonSendableKlass
-// CHECK-NEXT: #else
-// CHECK-NEXT: public func transferResultTest() -> test.NonSendableKlass
-// CHECK-NEXT: #endif
 public func transferResultTest() -> sending NonSendableKlass { fatalError() }
 
-// CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
 // CHECK-NEXT: public func transferArgAndResultTest(_ x: test.NonSendableKlass, _ y: sending test.NonSendableKlass, _ z: test.NonSendableKlass) -> sending test.NonSendableKlass
-// CHECK-NEXT: #else
-// CHECK-NEXT: public func transferArgAndResultTest(_ x: test.NonSendableKlass, _ y: __owned test.NonSendableKlass, _ z: test.NonSendableKlass) -> test.NonSendableKlass
-// CHECK-NEXT: #endif
 public func transferArgAndResultTest(_ x: NonSendableKlass, _ y: sending NonSendableKlass, _ z: NonSendableKlass) -> sending NonSendableKlass { fatalError() }
 
-// CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
 // CHECK-NEXT: public func argEmbeddedInType(_ fn: (sending test.NonSendableKlass) -> ())
-// CHECK-NEXT: #else
-// CHECK-NEXT: public func argEmbeddedInType(_ fn: (__owned test.NonSendableKlass) -> ())
-// CHECK-NEXT: #endif
 public func argEmbeddedInType(_ fn: (sending NonSendableKlass) -> ()) {}
 
-// CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
 // CHECK-NEXT: public func resultEmbeddedInType(_ fn: () -> sending test.NonSendableKlass)
-// CHECK-NEXT: #else
-// CHECK-NEXT: public func resultEmbeddedInType(_ fn: () -> test.NonSendableKlass)
-// CHECK-NEXT: #endif
 public func resultEmbeddedInType(_ fn: () -> sending NonSendableKlass) {}
 
-// CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
 // CHECK-NEXT: public func argAndResultEmbeddedInType(_ fn: (test.NonSendableKlass, sending test.NonSendableKlass, test.NonSendableKlass) -> sending test.NonSendableKlass)
-// CHECK-NEXT: #else
-// CHECK-NEXT: public func argAndResultEmbeddedInType(_ fn: (test.NonSendableKlass, __owned test.NonSendableKlass, test.NonSendableKlass) -> test.NonSendableKlass)
-// CHECK-NEXT: #endif
 public func argAndResultEmbeddedInType(_ fn: (NonSendableKlass, sending NonSendableKlass, NonSendableKlass) -> sending NonSendableKlass) {}
 
+// CHECK-LABEL: public class TestInKlass
 public class TestInKlass {
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public func testKlassArg(_ x: sending test.NonSendableKlass)
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public func testKlassArg(_ x: __owned test.NonSendableKlass)
-  // CHECK-NEXT: #endif
   public func testKlassArg(_ x: sending NonSendableKlass) { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public func testKlassResult() -> sending test.NonSendableKlass
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public func testKlassResult() -> test.NonSendableKlass
-  // CHECK-NEXT: #endif
   public func testKlassResult() -> sending NonSendableKlass { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public func testKlassArgAndResult(_ x: test.NonSendableKlass, _ y: sending test.NonSendableKlass, z: test.NonSendableKlass) -> sending test.NonSendableKlass
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public func testKlassArgAndResult(_ x: test.NonSendableKlass, _ y: __owned test.NonSendableKlass, z: test.NonSendableKlass) -> test.NonSendableKlass
-  // CHECK-NEXT: #endif
   public func testKlassArgAndResult(_ x: NonSendableKlass, _ y: sending NonSendableKlass, z: NonSendableKlass) -> sending NonSendableKlass { fatalError() }
 }
 
+// CHECK-LABEL: public struct TestInStruct
 public struct TestInStruct {
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public func testKlassArg(_ x: sending test.NonSendableKlass)
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public func testKlassArg(_ x: __owned test.NonSendableKlass)
-  // CHECK-NEXT: #endif
   public func testKlassArg(_ x: sending NonSendableKlass) { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public func testKlassResult() -> sending test.NonSendableKlass
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public func testKlassResult() -> test.NonSendableKlass
-  // CHECK-NEXT: #endif
   public func testKlassResult() -> sending NonSendableKlass { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public func testKlassArgAndResult(_ x: test.NonSendableKlass, _ y: sending test.NonSendableKlass, z: test.NonSendableKlass) -> sending test.NonSendableKlass
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public func testKlassArgAndResult(_ x: test.NonSendableKlass, _ y: __owned test.NonSendableKlass, z: test.NonSendableKlass) -> test.NonSendableKlass
-  // CHECK-NEXT: #endif
   public func testKlassArgAndResult(_ x: NonSendableKlass, _ y: sending NonSendableKlass, z: NonSendableKlass) -> sending NonSendableKlass { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public func testFunctionArg(_ x: () -> sending test.NonSendableKlass)
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public func testFunctionArg(_ x: () -> test.NonSendableKlass)
-  // CHECK-NEXT: #endif
   public func testFunctionArg(_ x: () -> sending NonSendableKlass) { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public func testFunctionResult() -> () -> sending test.NonSendableKlass
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public func testFunctionResult() -> () -> test.NonSendableKlass
-  // CHECK-NEXT: #endif
   public func testFunctionResult() -> (() -> sending NonSendableKlass) { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: @usableFromInline
   // CHECK-NEXT: internal func testUsableFromInlineKlassArg(_ x: sending test.NonSendableKlass)
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: @usableFromInline
-  // CHECK-NEXT: internal func testUsableFromInlineKlassArg(_ x: __owned test.NonSendableKlass)
-  // CHECK-NEXT: #endif
   @usableFromInline func testUsableFromInlineKlassArg(_ x: sending NonSendableKlass) { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: @usableFromInline
   // CHECK-NEXT: internal func testUsableFromInlineKlassResult() -> sending test.NonSendableKlass
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: @usableFromInline
-  // CHECK-NEXT: internal func testUsableFromInlineKlassResult() -> test.NonSendableKlass
-  // CHECK-NEXT: #endif
   @usableFromInline
   func testUsableFromInlineKlassResult() -> sending NonSendableKlass { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: @usableFromInline
   // CHECK-NEXT: internal func testUsableFromInlineKlassArgAndResult(_ x: test.NonSendableKlass, _ y: sending test.NonSendableKlass, z: test.NonSendableKlass) -> sending test.NonSendableKlass
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: @usableFromInline
-  // CHECK-NEXT: internal func testUsableFromInlineKlassArgAndResult(_ x: test.NonSendableKlass, _ y: __owned test.NonSendableKlass, z: test.NonSendableKlass) -> test.NonSendableKlass
-  // CHECK-NEXT: #endif
   @usableFromInline
   func testUsableFromInlineKlassArgAndResult(_ x: NonSendableKlass, _ y: sending NonSendableKlass, z: NonSendableKlass) -> sending NonSendableKlass { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: @usableFromInline
   // CHECK-NEXT: internal func testUsableFromInlineFunctionArg(_ x: () -> sending test.NonSendableKlass)
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: @usableFromInline
-  // CHECK-NEXT: internal func testUsableFromInlineFunctionArg(_ x: () -> test.NonSendableKlass)
-  // CHECK-NEXT: #endif
   @usableFromInline
   func testUsableFromInlineFunctionArg(_ x: () -> sending NonSendableKlass) { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: @usableFromInline
   // CHECK-NEXT: internal func testUsableFromInlineFunctionResult() -> () -> sending test.NonSendableKlass
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: @usableFromInline
-  // CHECK-NEXT: internal func testUsableFromInlineFunctionResult() -> () -> test.NonSendableKlass
-  // CHECK-NEXT: #endif
   @usableFromInline
   func testUsableFromInlineFunctionResult() -> (() -> sending NonSendableKlass) { fatalError() }
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public var publicVarFieldFunctionArg: (sending test.NonSendableKlass) -> ()
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public var publicVarFieldFunctionArg: (__owned test.NonSendableKlass) -> ()
-  // CHECK-NEXT: #endif
   public var publicVarFieldFunctionArg: (sending NonSendableKlass) -> ()
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: @usableFromInline
   // CHECK-NEXT: internal var internalVarFieldFunctionArg: (sending test.NonSendableKlass) -> ()
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: @usableFromInline
-  // CHECK-NEXT: internal var internalVarFieldFunctionArg: (__owned test.NonSendableKlass) -> ()
-  // CHECK-NEXT: #endif
   @usableFromInline
   var internalVarFieldFunctionArg: (sending NonSendableKlass) -> ()
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: public let publicLetFieldFunctionArg: (sending test.NonSendableKlass) -> ()
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public let publicLetFieldFunctionArg: (__owned test.NonSendableKlass) -> ()
-  // CHECK-NEXT: #endif
   public let publicLetFieldFunctionArg: (sending NonSendableKlass) -> ()
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: @usableFromInline
   // CHECK-NEXT: internal let internalLetFieldFunctionArg: (sending test.NonSendableKlass) -> ()
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: @usableFromInline
-  // CHECK-NEXT: internal let internalLetFieldFunctionArg: (__owned test.NonSendableKlass) -> ()
-  // CHECK-NEXT: #endif
   @usableFromInline
   let internalLetFieldFunctionArg: (sending NonSendableKlass) -> ()
 
-  // CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults
   // CHECK-NEXT: @usableFromInline
   // CHECK-NEXT: internal init(_ x: Swift.Int, transformWithResult: @escaping () async throws -> sending test.NonSendableKlass)
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: @usableFromInline
-  // CHECK-NEXT: internal init(_ x: Swift.Int, transformWithResult: @escaping () async throws -> test.NonSendableKlass)
-  // CHECK-NEXT: #endif
   @usableFromInline
   internal init(_ x: Int, transformWithResult: @escaping () async throws -> sending NonSendableKlass) { fatalError() }
 }
 
-// Make sure that we emit compiler(>= 5.3) when emitting the suppressing check
-// to make sure we do not fail if we fail to parse sending in the if block.
-
-// CHECK: #if compiler(>=5.3) && $NonescapableTypes // Suppression Count: 24
-// CHECK-NEXT: #if compiler(>=5.3) && $SendingArgsAndResults // Suppression Count: 25
-// CHECK-NEXT: @inlinable public func withCheckedContinuation<T>(isolation: isolated (any _Concurrency.Actor)? = #isolation, function: Swift.String = #function, _ body: (_Concurrency.CheckedContinuation<T, Swift.Never>) -> Swift.Void) async -> sending T {
-// CHECK-NEXT:  fatalError()
-// CHECK-NEXT: }
-// CHECK-NEXT: #else
-// CHECK-NEXT: @inlinable public func withCheckedContinuation<T>(isolation: isolated (any _Concurrency.Actor)? = #isolation, function: Swift.String = #function, _ body: (_Concurrency.CheckedContinuation<T, Swift.Never>) -> Swift.Void) async -> T {
+// CHECK-LABEL: @inlinable public func withCheckedContinuation<T>(isolation: isolated (any _Concurrency.Actor)? = #isolation, function: Swift.String = #function, _ body: (_Concurrency.CheckedContinuation<T, Swift.Never>) -> Swift.Void) async -> sending T {
 // CHECK-NEXT:  fatalError()
 // CHECK-NEXT: }
-// CHECK-NEXT: #endif
-// CHECK-NEXT: #endif
 @inlinable public func withCheckedContinuation<T>(
   isolation: isolated (any _Concurrency.Actor)? = #isolation,
   function: String = #function,
@@ -225,19 +110,10 @@ public struct TestInStruct {
   fatalError()
 }
 
-// CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults // Suppression Count: 26
-// CHECK-NEXT: public var publicGlobal: (sending test.NonSendableKlass) -> ()
-// CHECK-NEXT: #else
-// CHECK-NEXT: public var publicGlobal: (__owned test.NonSendableKlass) -> ()
-// CHECK-NEXT: #endif
+// CHECK-LABEL: public var publicGlobal: (sending test.NonSendableKlass) -> ()
 public var publicGlobal: (sending NonSendableKlass) -> () = { x in fatalError() }
 
-// CHECK-LABEL: #if compiler(>=5.3) && $SendingArgsAndResults // Suppression Count: 27
-// CHECK-NEXT: @usableFromInline
+// CHECK: @usableFromInline
 // CHECK-NEXT: internal var usableFromInlineGlobal: (sending test.NonSendableKlass) -> ()
-// CHECK-NEXT: #else
-// CHECK-NEXT: @usableFromInline
-// CHECK-NEXT: internal var usableFromInlineGlobal: (__owned test.NonSendableKlass) -> ()
-// CHECK-NEXT: #endif
 @usableFromInline
 internal var usableFromInlineGlobal: (sending NonSendableKlass) -> () = { x in fatalError() }
diff --git a/test/Concurrency/sending_continuation.swift b/test/Concurrency/sending_continuation.swift
index 7a6a489da3dbb..5f2fd68cfa321 100644
--- a/test/Concurrency/sending_continuation.swift
+++ b/test/Concurrency/sending_continuation.swift
@@ -51,7 +51,7 @@ func withCheckedContinuation_2a() async -> NonSendableKlass {
 
 @MainActor
 func withCheckedContinuation_3() async {
-  // x is main actor isolated since withCheckedContinuation is #isolated.
+  // x is MainActor isolated since withCheckedContinuation is #isolated.
   let x = await withCheckedContinuation { continuation in
     let x = NonSendableKlass()
     continuation.resume(returning: x)
@@ -80,7 +80,7 @@ func withCheckedContinuation_3a() async {
 
 @MainActor
 func withCheckedContinuation_4() async {
-  // x is main actor isolated since withCheckedContinuation is #isolated.
+  // x is MainActor isolated since withCheckedContinuation is #isolated.
   let y = NonSendableKlass()
   let x = await withCheckedContinuation { continuation in
     continuation.resume(returning: y)
@@ -95,7 +95,7 @@ func withCheckedContinuation_4() async {
 }
 
 func withCheckedContinuation_4a() async {
-  // x is main actor isolated since withCheckedContinuation is #isolated.
+  // x is MainActor isolated since withCheckedContinuation is #isolated.
   let y = NonSendableKlass()
   let x = await withCheckedContinuation { continuation in
     continuation.resume(returning: y)
@@ -182,7 +182,7 @@ func withUnsafeContinuation_2a() async -> NonSendableKlass {
 
 @MainActor
 func withUnsafeContinuation_3() async {
-  // x is main actor isolated since withUnsafeContinuation is #isolated.
+  // x is MainActor isolated since withUnsafeContinuation is #isolated.
   let x = await withUnsafeContinuation { continuation in
     let x = NonSendableKlass()
     continuation.resume(returning: x)
@@ -209,7 +209,7 @@ func withUnsafeContinuation_3a() async {
 
 @MainActor
 func withUnsafeContinuation_4() async {
-  // x is main actor isolated since withUnsafeContinuation is #isolated.
+  // x is MainActor isolated since withUnsafeContinuation is #isolated.
   let y = NonSendableKlass()
   let x = await withUnsafeContinuation { continuation in
     continuation.resume(returning: y)
@@ -224,7 +224,7 @@ func withUnsafeContinuation_4() async {
 }
 
 func withUnsafeContinuation_4a() async {
-  // x is main actor isolated since withUnsafeContinuation is #isolated.
+  // x is MainActor isolated since withUnsafeContinuation is #isolated.
   let y = NonSendableKlass()
   let x = await withUnsafeContinuation { continuation in
     continuation.resume(returning: y)
diff --git a/test/Concurrency/sending_interfacefile_printing.swift b/test/Concurrency/sending_interfacefile_printing.swift
index d3f1f72caee06..aa8b99aada3d5 100644
--- a/test/Concurrency/sending_interfacefile_printing.swift
+++ b/test/Concurrency/sending_interfacefile_printing.swift
@@ -11,41 +11,17 @@
 
 public class NonSendableKlass {}
 
-// CHECK: #if compiler(>=5.3) && $SendingArgsAndResults
-// CHECK-NEXT: public func test() -> sending MyFile.NonSendableKlass
-// CHECK-NEXT: #else
-// CHECK-NEXT: public func test() -> MyFile.NonSendableKlass
-// CHECK-NEXT: #endif
-
-// CHECK-REPR: #if compiler(>=5.3) && $SendingArgsAndResults
-// CHECK-REPR-NEXT: public func test() -> sending NonSendableKlass
-// CHECK-REPR-NEXT: #else
-// CHECK-REPR-NEXT: public func test() -> NonSendableKlass
-// CHECK-REPR-NEXT: #endif
+// CHECK: public func test() -> sending MyFile.NonSendableKlass
+
+// CHECK-REPR: public func test() -> sending NonSendableKlass
 public func test() -> sending NonSendableKlass { NonSendableKlass() }
 
-// CHECK: #if compiler(>=5.3) && $SendingArgsAndResults
-// CHECK-NEXT: public func test2(_ x: sending MyFile.NonSendableKlass)
-// CHECK-NEXT: #else
-// CHECK-NEXT: public func test2(_ x: __owned MyFile.NonSendableKlass)
-// CHECK-NEXT: #endif
-
-// CHECK-REPR: #if compiler(>=5.3) && $SendingArgsAndResults
-// CHECK-REPR-NEXT: public func test2(_ x: sending NonSendableKlass)
-// CHECK-REPR-NEXT: #else
-// CHECK-REPR-NEXT: public func test2(_ x: __owned NonSendableKlass)
-// CHECK-REPR-NEXT: #endif
+// CHECK: public func test2(_ x: sending MyFile.NonSendableKlass)
+
+// CHECK-REPR: public func test2(_ x: sending NonSendableKlass)
 public func test2(_ x: sending NonSendableKlass) {}
 
-// CHECK: #if compiler(>=5.3) && $SendingArgsAndResults
-// CHECK-NEXT: @_Concurrency.MainActor public var closure: () -> sending MyFile.NonSendableKlass
-// CHECK-NEXT: #else
-// CHECK-NEXT: @_Concurrency.MainActor public var closure: () -> MyFile.NonSendableKlass
-// CHECK-NEXT: #endif
-
-// CHECK-REPR: #if compiler(>=5.3) && $SendingArgsAndResults
-// CHECK-REPR-NEXT: @_Concurrency.MainActor public var closure: () -> sending NonSendableKlass
-// CHECK-REPR-NEXT: #else
-// CHECK-REPR-NEXT: @_Concurrency.MainActor public var closure: () -> NonSendableKlass
-// CHECK-REPR-NEXT: #endif
+// CHECK: @_Concurrency.MainActor public var closure: () -> sending MyFile.NonSendableKlass
+
+// CHECK-REPR: @_Concurrency.MainActor public var closure: () -> sending NonSendableKlass
 @MainActor public var closure: () -> sending NonSendableKlass = { NonSendableKlass() }
diff --git a/test/Concurrency/silisolationinfo_inference.sil b/test/Concurrency/silisolationinfo_inference.sil
index 4d440d9db1355..35d5dae45f6ee 100644
--- a/test/Concurrency/silisolationinfo_inference.sil
+++ b/test/Concurrency/silisolationinfo_inference.sil
@@ -876,3 +876,22 @@ bb2(%10 : @owned $any Error):
   dealloc_stack %2 : $*T
   throw %10 : $any Error
 }
+
+// CHECK-LABEL: begin running test 1 of 1 on optional_test: sil_isolation_info_inference with: @trace[0]
+// CHECK-NEXT: Input Value:   %5 = ref_element_addr %4 : $MyActor, #MyActor.ns
+// CHECK-NEXT: Isolation: 'argument'-isolated
+// CHECK-NEXT: end running test 1 of 1 on optional_test: sil_isolation_info_inference with: @trace[0]
+sil [ossa] @optional_test : $@convention(thin) (@sil_isolated @guaranteed Optional<MyActor>) -> () {
+bb0(%0 : @guaranteed $Optional<MyActor>):
+  specify_test "sil_isolation_info_inference @trace[0]"
+  debug_value %0 : $Optional<MyActor>, let, name "argument"
+  %1a = copy_value %0 : $Optional<MyActor>
+  %1b = begin_borrow %1a
+  %1c = unchecked_enum_data %1b : $Optional<MyActor>, #Optional.some!enumelt
+  %1d = ref_element_addr %1c : $MyActor, #MyActor.ns
+  debug_value [trace] %1d
+  end_borrow %1b
+  destroy_value %1a
+  %9999 = tuple ()
+  return %9999 : $()
+}
diff --git a/test/Concurrency/startImmediatelyIsolation.swift b/test/Concurrency/startImmediatelyIsolation.swift
new file mode 100644
index 0000000000000..a71e18fd1bcf0
--- /dev/null
+++ b/test/Concurrency/startImmediatelyIsolation.swift
@@ -0,0 +1,74 @@
+// RUN: %target-swift-frontend -parse-as-library -swift-version 6 -emit-sil -verify %s
+// REQUIRES: concurrency
+
+@available(SwiftStdlib 6.2, *)
+func sync() -> Task<String, Never> {
+  Task.immediate {
+    return ""
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+func async() async throws {
+  let t1 = Task.immediate {
+    return ""
+  }
+  let _: String = await t1.value
+
+  let td1 = Task.immediateDetached {
+    return ""
+  }
+  let _: String = await td1.value
+  
+  let t2: Task<String, Error> = Task.immediate {
+    throw CancellationError()
+  }
+  let _: String = try await t2.value
+
+  await withTaskGroup(of: Int.self) { group in
+    group.addImmediateTask { 1 }
+    _ = group.addImmediateTaskUnlessCancelled { 2 }
+  }
+  await withThrowingTaskGroup(of: Int.self) { group in
+    group.addImmediateTask { () async throws -> Int in 1 }
+    _ = group.addImmediateTaskUnlessCancelled { () async throws -> Int in 2 }
+  }
+  await withDiscardingTaskGroup { group in
+    group.addImmediateTask { }
+    _ = group.addImmediateTaskUnlessCancelled { }
+  }
+  try await withThrowingDiscardingTaskGroup { group in
+    group.addImmediateTask { () async throws -> Void in }
+    _ = group.addImmediateTaskUnlessCancelled { () async throws -> Void in }
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+actor TestSelfCapture {
+  func method() {}
+
+  func test() {
+    Task.immediate {
+      method() // Ok due to `@_implicitSelfCapture`
+    }
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+struct TestThrowing {
+  func test() {
+    // expected-error@+1{{invalid conversion from throwing function of type '() throws -> Void' to non-throwing function type '@isolated(any) () async -> Void'}}
+    let t: Task<Void, Never> = Task.immediate {
+      throw Boom()
+    }
+    _ = t
+
+    // ok
+    let t2: Task<Void, Error> = Task.immediate {
+      throw Boom()
+    }
+    _ = t2
+  }
+}
+
+struct Boom: Error {}
diff --git a/test/Concurrency/startSynchronouslyIsolation.swift b/test/Concurrency/startSynchronouslyIsolation.swift
deleted file mode 100644
index 8837fecdba3f1..0000000000000
--- a/test/Concurrency/startSynchronouslyIsolation.swift
+++ /dev/null
@@ -1,40 +0,0 @@
-// RUN: %target-build-swift -swift-version 6 %s -strict-concurrency=complete -Xfrontend -verify
-
-// REQUIRES: concurrency
-
-@available(SwiftStdlib 6.2, *)
-func sync() -> Task<String, Never> {
-  Task.startSynchronously {
-    return ""
-  }
-}
-
-@available(SwiftStdlib 6.2, *)
-func async() async throws {
-  let t1 = Task.startSynchronously {
-    return ""
-  }
-  let _: String = await t1.value
-  
-  let t2: Task<String, Error> = Task.startSynchronously {
-    throw CancellationError()
-  }
-  let _: String = try await t2.value
-
-  await withTaskGroup(of: Int.self) { group in
-    group.startTaskSynchronously { 1 }
-    group.startTaskSynchronouslyUnlessCancelled { 2 }
-  }
-  await withThrowingTaskGroup(of: Int.self) { group in
-    group.startTaskSynchronously { () async throws -> Int in 1 }
-    group.startTaskSynchronouslyUnlessCancelled { () async throws -> Int in 2 }
-  }
-  await withDiscardingTaskGroup { group in
-    group.startTaskSynchronously { }
-    group.startTaskSynchronouslyUnlessCancelled { }
-  }
-  try await withThrowingDiscardingTaskGroup { group in
-    group.startTaskSynchronously { () async throws -> Void in }
-    group.startTaskSynchronouslyUnlessCancelled { () async throws -> Void in }
-  }
-}
diff --git a/test/Concurrency/strict_concurrency_minimal.swift b/test/Concurrency/strict_concurrency_minimal.swift
index baf331a4f8c7f..9d37e5b5ee854 100644
--- a/test/Concurrency/strict_concurrency_minimal.swift
+++ b/test/Concurrency/strict_concurrency_minimal.swift
@@ -19,8 +19,8 @@ class C3 { }
 extension C3: Sendable { }
 
 struct S1: Sendable {
-  let c1: C1 // expected-warning{{stored property 'c1' of 'Sendable'-conforming struct 'S1' has non-sendable type 'C1'}}
-  let c2: C2 // expected-warning{{stored property 'c2' of 'Sendable'-conforming struct 'S1' has non-sendable type 'C2'}}
+  let c1: C1 // expected-warning{{stored property 'c1' of 'Sendable'-conforming struct 'S1' has non-Sendable type 'C1'}}
+  let c2: C2 // expected-warning{{stored property 'c2' of 'Sendable'-conforming struct 'S1' has non-Sendable type 'C2'}}
   let c3: C3 // expected-warning{{stored property 'c3'}}
 }
 
@@ -42,22 +42,22 @@ func passSendable(
 ) async {
   // Don't warn about implicitly non-Sendable types when minimal is
   // enabled... but do when we are doing targeted
-  takeSendable { print(c1) } // expected-targeted-warning {{capture of 'c1' with non-sendable type 'C1' in a '@Sendable' closure}}
-  takeSendable { print(fn) } // expected-targeted-warning {{capture of 'fn' with non-sendable type '() -> Void' in a '@Sendable' closure}}
+  takeSendable { print(c1) } // expected-targeted-warning {{capture of 'c1' with non-Sendable type 'C1' in a '@Sendable' closure}}
+  takeSendable { print(fn) } // expected-targeted-warning {{capture of 'fn' with non-Sendable type '() -> Void' in a '@Sendable' closure}}
   // expected-targeted-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
   // Warn about explicitly non-Sendable types
-  takeSendable { print(c2) } // expected-warning {{capture of 'c2' with non-sendable type 'C2' in a '@Sendable' closure}}
-  takeSendable { print(c3) } // expected-warning {{capture of 'c3' with non-sendable type 'C3' in a '@Sendable' closure}}
+  takeSendable { print(c2) } // expected-warning {{capture of 'c2' with non-Sendable type 'C2' in a '@Sendable' closure}}
+  takeSendable { print(c3) } // expected-warning {{capture of 'c3' with non-Sendable type 'C3' in a '@Sendable' closure}}
 
   // Don't warn about explicitly Sendable type, even when it's wrong.
   takeSendable { print(s1) }
 
   // Don't warn when we wrapped an implicitly non-Sendable type in a struct unless we are >= targeted
-  takeSendable { print(s2) } // expected-targeted-warning {{capture of 's2' with non-sendable type 'S2' in a '@Sendable' closure}}
+  takeSendable { print(s2) } // expected-targeted-warning {{capture of 's2' with non-Sendable type 'S2' in a '@Sendable' closure}}
 
   // FIXME: Ideally, we would warn about cases where a type in this module is
   // inferred to be non-Sendable based on something explicitly non-Sendable,
   // like in the case below. We do warn about it with >= targeted.
-  takeSendable { print(s3) } // expected-targeted-warning {{capture of 's3' with non-sendable type 'S3' in a '@Sendable' closure}}
+  takeSendable { print(s3) } // expected-targeted-warning {{capture of 's3' with non-Sendable type 'S3' in a '@Sendable' closure}}
 }
diff --git a/test/Concurrency/swiftsettings_defaultIsolation.swift b/test/Concurrency/swiftsettings_defaultIsolation.swift
deleted file mode 100644
index 7ecb695a07722..0000000000000
--- a/test/Concurrency/swiftsettings_defaultIsolation.swift
+++ /dev/null
@@ -1,54 +0,0 @@
-// RUN: %target-swift-frontend -enable-experimental-feature SwiftSettings -c -verify -swift-version 6 -verify-additional-prefix nonisolated- -disable-availability-checking %s
-// RUN: %target-swift-frontend -enable-experimental-feature SwiftSettings -c -verify -swift-version 6 -verify-additional-prefix main-actor- -disable-availability-checking -DSWIFT_SETTINGS_MAIN_ACTOR %s
-// RUN: %target-swift-frontend -default-isolation MainActor -enable-experimental-feature SwiftSettings -c -verify -swift-version 6 -disable-availability-checking -verify-additional-prefix main-actor- %s
-// RUN: %target-swift-frontend -default-isolation MainActor -enable-experimental-feature SwiftSettings -c -verify -swift-version 6 -disable-availability-checking -verify-additional-prefix nonisolated- -DSWIFT_SETTINGS_NONISOLATED %s
-
-// REQUIRES: asserts
-// REQUIRES: concurrency
-// REQUIRES: swift_feature_SwiftSettings
-
-#if SWIFT_SETTINGS_MAIN_ACTOR
-
-#SwiftSettings(.defaultIsolation(MainActor.self))
-
-#endif
-
-#if SWIFT_SETTINGS_NONISOLATED
-
-#SwiftSettings(.defaultIsolation(nil))
-
-#endif
-
-class UnspecifiedKlass {}
-nonisolated class NonisolatedKlass {}
-
-func unspecifiedFunc<T>(_ t: T) async {}
-nonisolated func nonisolatedFunc<T>(_ t: T) async {}
-@MainActor func mainActorFunc<T>(_ t: T) async {}
-
-func test1(_ x: UnspecifiedKlass) async {
-  await unspecifiedFunc(x)
-}
-
-func test2(_ x: NonisolatedKlass) async {
-  await unspecifiedFunc(x)
-}
-
-func test3(_ x: UnspecifiedKlass) async {
-  await nonisolatedFunc(x)
-}
-
-func test4(_ x: NonisolatedKlass) async {
-  await nonisolatedFunc(x) // expected-main-actor-error {{sending 'x' risks causing data races}}
-  // expected-main-actor-note @-1 {{sending main actor-isolated 'x' to nonisolated global function 'nonisolatedFunc' risks causing data races between nonisolated and main actor-isolated uses}}
-}
-
-func test5(_ x: UnspecifiedKlass) async {
-  await mainActorFunc(x) // expected-nonisolated-error {{sending 'x' risks causing data races}}
-  // expected-nonisolated-note @-1 {{sending task-isolated 'x' to main actor-isolated global function 'mainActorFunc' risks causing data races between main actor-isolated and task-isolated uses}}
-}
-
-func test6(_ x: NonisolatedKlass) async {
-  await mainActorFunc(x) // expected-nonisolated-error {{sending 'x' risks causing data races}}
-  // expected-nonisolated-note @-1 {{sending task-isolated 'x' to main actor-isolated global function 'mainActorFunc' risks causing data races between main actor-isolated and task-isolated uses}}
-}
diff --git a/test/Concurrency/task_local.swift b/test/Concurrency/task_local.swift
index cbc372eed8ac9..12b6765632f6f 100644
--- a/test/Concurrency/task_local.swift
+++ b/test/Concurrency/task_local.swift
@@ -1,14 +1,17 @@
 // RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -strict-concurrency=targeted -target %target-swift-5.1-abi-triple -emit-sil -verify -o /dev/null %s
 // RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -strict-concurrency=complete -verify-additional-prefix complete- -target %target-swift-5.1-abi-triple -emit-sil -verify -o /dev/null %s
-// RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -strict-concurrency=complete -verify-additional-prefix complete- -target %target-swift-5.1-abi-triple -emit-sil -verify -o /dev/null %s -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @available(SwiftStdlib 5.1, *)
 struct TL {
   @TaskLocal // expected-note{{in expansion of macro 'TaskLocal' on static property 'number' here}}
   static var number: Int = 0
+  /*
+  expected-expansion@-2:29{{
+    expected-note@1:8{{change 'let' to 'var' to make it mutable}}
+  }}
+  */
 
   @TaskLocal
   static var someNil: Int?
@@ -16,6 +19,11 @@ struct TL {
   // expected-note@+1{{in expansion of macro 'TaskLocal' on static property 'noValue' here}}
   @TaskLocal // expected-error{{@TaskLocal' property must have default value, or be optional}}
   static var noValue: Int // expected-note{{'noValue' declared here}}
+  /*
+  expected-expansion@-2:26{{
+    expected-error@3:9{{cannot find '$noValue' in scope; did you mean 'noValue'?}}
+  }}
+  */
 
   @TaskLocal // expected-error{{'@TaskLocal' can only be applied to 'static' property}}
   var notStatic: String?
diff --git a/test/Concurrency/task_naming_availability.swift b/test/Concurrency/task_naming_availability.swift
new file mode 100644
index 0000000000000..c7c45d67e8216
--- /dev/null
+++ b/test/Concurrency/task_naming_availability.swift
@@ -0,0 +1,73 @@
+// RUN: %target-swift-frontend -emit-sil -verify -o /dev/null -verify %s
+
+struct Boom: Error {}
+
+@available(SwiftStdlib 6.2, *)
+func testName() {
+  _ = Task.name
+}
+
+@available(SwiftStdlib 6.0, *)
+func taskExecutor() async {
+  Task(name: "name", executorPreference: nil) { }
+  Task(name: "name", executorPreference: nil) { throw Boom() }
+
+  Task.detached(name: "name", executorPreference: nil) { throw Boom() }
+
+  await withTaskGroup(of: Void.self) { group in
+    group.addTask(name: "name", executorPreference: nil) {
+      ()
+    }
+  }
+  await withThrowingTaskGroup(of: Void.self) { group in
+    group.addTask(name: "name", executorPreference: nil) {
+      ()
+    }
+  }
+
+  await withDiscardingTaskGroup { group in
+    group.addTask(name: "name", executorPreference: nil) {
+      ()
+    }
+  }
+  try! await withThrowingDiscardingTaskGroup { group in
+    group.addTask(name: "name", executorPreference: nil) {
+      ()
+    }
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+func backDeployedNames() async {
+  Task(name: "name") { }
+  Task(name: "name") { throw Boom() }
+
+  Task.detached(name: "name") { }
+  Task.detached(name: "name") { throw Boom() }
+
+  await withTaskGroup(of: Void.self) { group in
+    group.addTask(name: "name") {
+      ()
+    }
+  }
+  await withThrowingTaskGroup(of: Void.self) { group in
+    group.addTask(name: "name") {
+      ()
+    }
+  }
+}
+
+@available(SwiftStdlib 5.9, *)
+func backDeployedDiscarding() async {
+  await withDiscardingTaskGroup { group in
+    group.addTask(name: "name") {
+      ()
+    }
+  }
+  try! await withThrowingDiscardingTaskGroup { group in
+    group.addTask(name: "name") {
+      ()
+    }
+  }
+}
+
diff --git a/test/Concurrency/taskgroup_cancelAll_from_child.swift b/test/Concurrency/taskgroup_cancelAll_from_child.swift
index 84b31beb62432..b05d6c8d52345 100644
--- a/test/Concurrency/taskgroup_cancelAll_from_child.swift
+++ b/test/Concurrency/taskgroup_cancelAll_from_child.swift
@@ -1,10 +1,8 @@
-// RUN: %target-swift-frontend -disable-availability-checking %s -emit-sil -o /dev/null -verify
-// RUN: %target-swift-frontend -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
-// RUN: %target-swift-frontend -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend -disable-availability-checking %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
+// RUN: %target-swift-frontend -disable-availability-checking %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated
+// RUN: %target-swift-frontend -disable-availability-checking %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=targeted
+// RUN: %target-swift-frontend -disable-availability-checking %s -emit-sil -o /dev/null -verify -verify-ignore-unrelated -strict-concurrency=complete
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @available(SwiftStdlib 5.1, *)
 func test_taskGroup_cancelAll() async {
@@ -17,14 +15,14 @@ func test_taskGroup_cancelAll() async {
        }
 
        group.spawn { // expected-error {{escaping closure captures 'inout' parameter 'group'}}
-         group.cancelAll() //expected-warning{{capture of 'group' with non-sendable type 'TaskGroup<Int>' in a '@Sendable' closure}}
+         group.cancelAll() //expected-warning{{capture of 'group' with non-Sendable type 'TaskGroup<Int>' in a '@Sendable' closure}}
          //expected-warning@-1{{mutable capture of 'inout' parameter 'group' is not allowed in concurrently-executing code; this is an error in the Swift 6 language mode}}
          // expected-note@-2 {{captured here}}
 
          return 0
        }
        group.spawn { [group] in
-         group.cancelAll() //expected-warning{{capture of 'group' with non-sendable type 'TaskGroup<Int>' in a '@Sendable' closure}}
+         group.cancelAll() //expected-warning{{capture of 'group' with non-Sendable type 'TaskGroup<Int>' in a '@Sendable' closure}}
          return 0
        }
        _ = await group.next()
diff --git a/test/Concurrency/toplevel/async-5-top-level.swift b/test/Concurrency/toplevel/async-5-top-level.swift
index 835f5abb7a475..f5236465051da 100644
--- a/test/Concurrency/toplevel/async-5-top-level.swift
+++ b/test/Concurrency/toplevel/async-5-top-level.swift
@@ -23,9 +23,8 @@ func nonIsolatedAsync() async {
     await print(a)
     a = a + 10
     // expected-warning@-1:5 {{main actor-isolated var 'a' can not be mutated from a nonisolated context}}
-    // expected-warning@-2:9 {{expression is 'async' but is not marked with 'await'}}{{9-9=await }}
-    // expected-note@-3:9 {{property access is 'async'}}
-    // expected-note@-4 {{consider declaring an isolated method on 'MainActor' to perform the mutation}}
+    // expected-warning@-2:9 {{main actor-isolated var 'a' cannot be accessed from outside of the actor}}{{9-9=await }}
+    // expected-note@-3 {{consider declaring an isolated method on 'MainActor' to perform the mutation}}
 }
 
 @MainActor
diff --git a/test/Concurrency/toplevel/async-6-top-level.swift b/test/Concurrency/toplevel/async-6-top-level.swift
index f1726a01ea7a8..1bc4eb299a8c4 100644
--- a/test/Concurrency/toplevel/async-6-top-level.swift
+++ b/test/Concurrency/toplevel/async-6-top-level.swift
@@ -22,9 +22,8 @@ func nonIsolatedAsync() async {
     await print(a)
     a = a + 10
     // expected-error@-1:5 {{main actor-isolated var 'a' can not be mutated from a nonisolated context}}
-    // expected-error@-2:9 {{expression is 'async' but is not marked with 'await'}}
-    // expected-note@-3:9 {{property access is 'async'}}
-    // expected-note@-4 {{consider declaring an isolated method on 'MainActor' to perform the mutation}}
+    // expected-error@-2:9 {{main actor-isolated var 'a' cannot be accessed from outside of the actor}} {{9-9=await }}
+    // expected-note@-3 {{consider declaring an isolated method on 'MainActor' to perform the mutation}}
 }
 
 @MainActor
diff --git a/test/Concurrency/toplevel/no-async-6-top-level.swift b/test/Concurrency/toplevel/no-async-6-top-level.swift
index f497e59f704a7..e5e27fcc994dd 100644
--- a/test/Concurrency/toplevel/no-async-6-top-level.swift
+++ b/test/Concurrency/toplevel/no-async-6-top-level.swift
@@ -24,9 +24,8 @@ func isolatedSync() {
 func nonIsolatedAsync() async {
   await print(a)
   a = a + 10 // expected-error{{main actor-isolated var 'a' can not be mutated from a nonisolated context}}
-  // expected-note@-1{{property access is 'async'}}
-  // expected-error@-2{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-3{{consider declaring an isolated method on 'MainActor' to perform the mutation}}
+  // expected-error@-1{{main actor-isolated var 'a' cannot be accessed from outside of the actor}} {{7-7=await }}
+  // expected-note@-2{{consider declaring an isolated method on 'MainActor' to perform the mutation}}
 }
 
 @MainActor
diff --git a/test/Concurrency/toplevel/synchronous_mainactor.swift b/test/Concurrency/toplevel/synchronous_mainactor.swift
index 414914d92fda5..b28b15da122b8 100644
--- a/test/Concurrency/toplevel/synchronous_mainactor.swift
+++ b/test/Concurrency/toplevel/synchronous_mainactor.swift
@@ -10,8 +10,7 @@ func unsafeAccess() { // expected-note{{add '@MainActor' to make global function
 }
 
 func unsafeAsyncAccess() async {
-    print(a) // expected-error@:5{{expression is 'async' but is not marked with 'await'}}{{5-5=await }}
-             // expected-note@-1:11{{property access is 'async'}}
+    print(a) // expected-error@:11{{main actor-isolated var 'a' cannot be accessed from outside of the actor}}{{5-5=await }}
 }
 
 @MainActor
diff --git a/test/Concurrency/transfernonsendable.sil b/test/Concurrency/transfernonsendable.sil
index 95d0355aab509..debeff4930d76 100644
--- a/test/Concurrency/transfernonsendable.sil
+++ b/test/Concurrency/transfernonsendable.sil
@@ -158,13 +158,14 @@ bb0:
   %f = function_ref @transferIndirectWithOutResult : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> @out τ_0_0
   apply [caller_isolation=nonisolated] [callee_isolation=global_actor] %f<NonSendableKlass>(%1, %0) : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> @out τ_0_0 // expected-warning {{}}
 
+  // We do not error here on use after send since %1 is already isolated to the
+  // same global actor as transferIndirect which is not considered to be a
+  // send. We leave the actual error to be the error about returning an isolated
+  // value into a non-isolated context.
   %f2 = function_ref @transferIndirect : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
   apply [caller_isolation=nonisolated] [callee_isolation=global_actor] %f2<NonSendableKlass>(%1) : $@convention(thin) @async <τ_0_0> (@in_guaranteed τ_0_0) -> ()
-  // expected-warning @-1 {{}}
-  // expected-note @-2 {{}}
   %useIndirect = function_ref @useIndirect : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> ()
   apply %useIndirect<NonSendableKlass>(%1) : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> ()
-  // expected-note @-1 {{access can happen concurrently}}
 
   destroy_addr %1 : $*NonSendableKlass
   dealloc_stack %1 : $*NonSendableKlass
diff --git a/test/Concurrency/transfernonsendable.swift b/test/Concurrency/transfernonsendable.swift
index 1cafd30aa7131..c0d22171b7ae2 100644
--- a/test/Concurrency/transfernonsendable.swift
+++ b/test/Concurrency/transfernonsendable.swift
@@ -1,22 +1,18 @@
-// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -disable-availability-checking -verify -verify-additional-prefix tns-  %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
-
-// This run validates that for specific test cases around closures, we properly
-// emit errors in the type checker before we run sns. This ensures that we know that
-// these cases can't happen when SNS is enabled.
-//
-// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -disable-availability-checking -verify -verify-additional-prefix typechecker-only- -DTYPECHECKER_ONLY %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -disable-availability-checking -verify -verify-additional-prefix ni- %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -disable-availability-checking -verify -verify-additional-prefix ni-ns- %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
 ////////////////////////
 
-/// Classes are always non-sendable, so this is non-sendable
+/// Classes are always non-Sendable, so this is non-Sendable
 class NonSendableKlass { // expected-complete-note 53{{}}
   // expected-typechecker-only-note @-1 3{{}}
-  // expected-tns-note @-2 {{}}
+  // expected-note @-2 {{}}
   var field: NonSendableKlass? = nil
   var boolean: Bool = false
 
@@ -69,6 +65,7 @@ final class FinalMainActorIsolatedKlass {
 func useInOut<T>(_ x: inout T) {}
 func useValue<T>(_ x: T) {}
 func useValueAsync<T>(_ x: T) async {}
+@concurrent func useValueAsyncConcurrent<T>(_ x: T) async {}
 
 @MainActor func transferToMain<T>(_ t: T) async {}
 
@@ -93,22 +90,28 @@ struct SendableGenericStruct : Sendable {
   var x = SendableKlass()
 }
 
+enum MyEnum<T> {
+    case none
+    indirect case some(NonSendableKlass)
+    case more(T)
+}
+
 ////////////////////////////
 // MARK: Actor Self Tests //
 ////////////////////////////
 
 extension MyActor {
   func warningIfCallingGetter() async {
-    await self.klass.asyncCall() // expected-complete-warning {{passing argument of non-sendable type 'NonSendableKlass' outside of actor-isolated context may introduce data races}}
-    // expected-tns-warning @-1 {{sending 'self.klass' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'self'-isolated 'self.klass' to nonisolated instance method 'asyncCall()' risks causing data races between nonisolated and 'self'-isolated uses}}
+    await self.klass.asyncCall() // expected-complete-warning {{passing argument of non-Sendable type 'NonSendableKlass' outside of actor-isolated context may introduce data races}}
+    // expected-ni-warning @-1 {{sending 'self.klass' risks causing data races}}
+    // expected-ni-note @-2 {{sending 'self'-isolated 'self.klass' to nonisolated instance method 'asyncCall()' risks causing data races between nonisolated and 'self'-isolated uses}}
   }
 
   func warningIfCallingAsyncOnFinalField() async {
     // Since we are calling finalKlass directly, we emit a warning here.
-    await self.finalKlass.asyncCall() // expected-complete-warning {{passing argument of non-sendable type 'NonSendableKlass' outside of actor-isolated context may introduce data races}}
-    // expected-tns-warning @-1 {{sending 'self.finalKlass' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'self'-isolated 'self.finalKlass' to nonisolated instance method 'asyncCall()' risks causing data races between nonisolated and 'self'-isolated uses}}
+    await self.finalKlass.asyncCall() // expected-complete-warning {{passing argument of non-Sendable type 'NonSendableKlass' outside of actor-isolated context may introduce data races}}
+    // expected-ni-warning @-1 {{sending 'self.finalKlass' risks causing data races}}
+    // expected-ni-note @-2 {{sending 'self'-isolated 'self.finalKlass' to nonisolated instance method 'asyncCall()' risks causing data races between nonisolated and 'self'-isolated uses}}
   }
 
   // We do not warn on this since we warn in the caller of our getter instead.
@@ -120,9 +123,9 @@ extension MyActor {
 extension FinalActor {
   func warningIfCallingAsyncOnFinalField() async {
     // Since our whole class is final, we emit the error directly here.
-    await self.klass.asyncCall() // expected-complete-warning {{passing argument of non-sendable type 'NonSendableKlass' outside of actor-isolated context may introduce data races}}
-    // expected-tns-warning @-1 {{sending 'self.klass' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'self'-isolated 'self.klass' to nonisolated instance method 'asyncCall()' risks causing data races between nonisolated and 'self'-isolated uses}}
+    await self.klass.asyncCall() // expected-complete-warning {{passing argument of non-Sendable type 'NonSendableKlass' outside of actor-isolated context may introduce data races}}
+    // expected-ni-warning @-1 {{sending 'self.klass' risks causing data races}}
+    // expected-ni-note @-2 {{sending 'self'-isolated 'self.klass' to nonisolated instance method 'asyncCall()' risks causing data races between nonisolated and 'self'-isolated uses}}
   }
 }
 
@@ -150,14 +153,14 @@ func closureInOut(_ a: MyActor) async {
   closure = { useInOut(&contents) }
 
   await a.useKlass(ns0)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass'}}
-  // expected-tns-warning @-2 {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-3 {{sending 'ns0' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass'}}
+  // expected-warning @-2 {{sending 'ns0' risks causing data races}}
+  // expected-note @-3 {{sending 'ns0' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
 
   if await booleanFlag {
-    await a.useKlass(ns1) // expected-tns-note {{access can happen concurrently}}
+    await a.useKlass(ns1) // expected-note {{access can happen concurrently}}
   } else {
-    closure() // expected-tns-note {{access can happen concurrently}}
+    closure() // expected-note {{access can happen concurrently}}
   }
 }
 
@@ -173,17 +176,17 @@ func closureInOutDifferentActor(_ a: MyActor, _ a2: MyActor) async {
   closure = { useInOut(&contents) }
 
   await a.useKlass(ns0)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass'}}
-  // expected-tns-warning @-2 {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-3 {{sending 'ns0' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass'}}
+  // expected-warning @-2 {{sending 'ns0' risks causing data races}}
+  // expected-note @-3 {{sending 'ns0' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
 
   // We only emit a warning on the first use we see, so make sure we do both
   // the use and the closure.
   if await booleanFlag {
-    await a2.useKlass(ns1) // expected-tns-note {{access can happen concurrently}}
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass'}}
+    await a2.useKlass(ns1) // expected-note {{access can happen concurrently}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass'}}
   } else {
-    closure() // expected-tns-note {{access can happen concurrently}}
+    closure() // expected-note {{access can happen concurrently}}
   }
 }
 
@@ -198,17 +201,17 @@ func closureInOut2(_ a: MyActor) async {
 
   var closure = {}
 
-  await a.useKlass(ns0) // expected-tns-warning {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns0' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass'}}
+  await a.useKlass(ns0) // expected-warning {{sending 'ns0' risks causing data races}}
+  // expected-note @-1 {{sending 'ns0' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass'}}
 
-  closure = { useInOut(&contents) } // expected-tns-note {{access can happen concurrently}}
+  closure = { useInOut(&contents) } // expected-note {{access can happen concurrently}}
 
-  await a.useKlass(ns1) // expected-tns-warning {{sending 'ns1' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns1' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass'}}
+  await a.useKlass(ns1) // expected-warning {{sending 'ns1' risks causing data races}}
+  // expected-note @-1 {{sending 'ns1' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass'}}
 
-  closure() // expected-tns-note {{access can happen concurrently}}
+  closure() // expected-note {{access can happen concurrently}}
 }
 
 func closureNonInOut(_ a: MyActor) async {
@@ -222,15 +225,15 @@ func closureNonInOut(_ a: MyActor) async {
   var closure = {}
 
   await a.useKlass(ns0)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass'}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass'}}
 
   closure = { useValue(contents) }
 
-  await a.useKlass(ns1) // expected-tns-warning {{sending 'ns1' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns1' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass'}}
+  await a.useKlass(ns1) // expected-warning {{sending 'ns1' risks causing data races}}
+  // expected-note @-1 {{sending 'ns1' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass'}}
 
-  closure() // expected-tns-note {{access can happen concurrently}}
+  closure() // expected-note {{access can happen concurrently}}
 }
 
 // TODO: Rework the nonisolated closure so we only treat nonisolated closures
@@ -242,11 +245,11 @@ func transferNonIsolatedNonAsyncClosureTwice() async {
 
   // This is nonisolated and non-async... we can transfer it safely.
   var actorCaptureClosure = { print(a) }
-  await transferToMain(actorCaptureClosure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  await transferToMain(actorCaptureClosure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
   // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
   actorCaptureClosure = { print(a) }
-  await transferToMain(actorCaptureClosure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  await transferToMain(actorCaptureClosure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
   // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 }
 
@@ -256,10 +259,10 @@ extension MyActor {
     let closure: () -> () = {
       print(self.klass)
     }
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 
   func simpleClosureCaptureSelfAndTransferThroughTuple() async {
@@ -267,10 +270,10 @@ extension MyActor {
       print(self.klass)
     }
     let x = (1, closure)
-    await transferToMain(x) // expected-complete-warning {{passing argument of non-sendable type '(Int, () -> ())' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-complete-warning {{passing argument of non-Sendable type '(Int, () -> ())' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending value of non-Sendable type '(Int, () -> ())' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated value of non-Sendable type '(Int, () -> ())' to main actor-isolated global function 'transferToMain' risks causing races in between 'self'-isolated and main actor-isolated uses}}
+    // expected-warning @-2 {{sending value of non-Sendable type '(Int, () -> ())' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated value of non-Sendable type '(Int, () -> ())' to main actor-isolated global function 'transferToMain' risks causing races in between 'self'-isolated and main actor-isolated uses}}
   }
 
   func simpleClosureCaptureSelfAndTransferThroughTupleBackwards() async {
@@ -279,8 +282,8 @@ extension MyActor {
     }
 
     let x = (closure, 1)
-    await transferToMain(x) // expected-tns-warning {{sending value of non-Sendable type '(() -> (), Int)' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated value of non-Sendable type '(() -> (), Int)' to main actor-isolated global function 'transferToMain' risks causing races in between 'self'-isolated and main actor-isolated uses}}
+    await transferToMain(x) // expected-warning {{sending value of non-Sendable type '(() -> (), Int)' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated value of non-Sendable type '(() -> (), Int)' to main actor-isolated global function 'transferToMain' risks causing races in between 'self'-isolated and main actor-isolated uses}}
   }
 
   func simpleClosureCaptureSelfAndTransferThroughOptional() async {
@@ -288,9 +291,9 @@ extension MyActor {
       print(self.klass)
     }
     let x: Any? = (1, closure)
-    await transferToMain(x) // expected-complete-warning {{passing argument of non-sendable type 'Any?' into main actor-isolated context may introduce data races}}
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    await transferToMain(x) // expected-complete-warning {{passing argument of non-Sendable type 'Any?' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 
   func simpleClosureCaptureSelfAndTransferThroughOptionalBackwards() async {
@@ -301,9 +304,9 @@ extension MyActor {
     // we are forming is an Any?  so we actually form the tuple as an object and
     // store it all as once.
     let x: Any? = (closure, 1)
-    await transferToMain(x) // expected-complete-warning {{passing argument of non-sendable type 'Any?' into main actor-isolated context may introduce data races}}
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    await transferToMain(x) // expected-complete-warning {{passing argument of non-Sendable type 'Any?' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 
   func simpleClosureCaptureSelfWithReinit() async {
@@ -312,16 +315,16 @@ extension MyActor {
     }
 
     // Error here.
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
 
     closure = {}
 
     // But not here.
     await transferToMain(closure)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
   }
 
@@ -330,7 +333,7 @@ extension MyActor {
 
     // No error here.
     await transferToMain(closure)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
     closure = {
@@ -338,20 +341,20 @@ extension MyActor {
     }
 
     // Error here.
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 
   func simpleClosureCaptureSelfWithReinit3() async {
     var closure: () -> () = {}
 
     // We get a transfer after use error.
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local actor-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local actor-isolated uses}}
 
     if await booleanFlag {
       closure = {
@@ -359,11 +362,11 @@ extension MyActor {
       }
     }
 
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-note @-2 {{access can happen concurrently}}
-    // expected-tns-warning @-3 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-4 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-note @-2 {{access can happen concurrently}}
+    // expected-warning @-3 {{sending 'closure' risks causing data races}}
+    // expected-note @-4 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 
   // In this case, we reinit along both paths, but only one has an actor derived
@@ -372,7 +375,7 @@ extension MyActor {
     var closure: () -> () = {}
 
     await transferToMain(closure)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
     if await booleanFlag {
@@ -383,39 +386,21 @@ extension MyActor {
       closure = {}
     }
 
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-  }
-
-  #if TYPECHECKER_ONLY
-
-  func simpleClosureCaptureSelfThroughTupleWithFieldAccess() async {
-    // In this case, we erase that we accessed self so we hit a type checker
-    // error. We could make this a SNS error, but since in the other cases where
-    // we have a nonisolated non-async we are probably going to change it to be
-    // async as well making these errors go away.
-    let x = (self, 1)
-    let closure: () -> () = {
-      print(x.0.klass) // expected-typechecker-only-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
-    }
-    await transferToMain(closure)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
-    // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 
-  #endif
-
   func simpleClosureCaptureSelfThroughTuple() async {
     let x = (self, self.klass)
     let closure: () -> () = {
       print(x.1)
     }
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 
   func simpleClosureCaptureSelfThroughTuple2() async {
@@ -423,10 +408,10 @@ extension MyActor {
     let closure: () -> () = {
       print(x.1)
     }
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 
   func simpleClosureCaptureSelfThroughOptional() async {
@@ -434,86 +419,28 @@ extension MyActor {
     let closure: () -> () = {
       print(x as Any)
     }
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 }
 
 func testSimpleLetClosureCaptureActor() async {
   let a = MyActor()
   let closure = { print(a) }
-  await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
   // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 }
 
-#if TYPECHECKER_ONLY
-
-func testSimpleLetClosureCaptureActorField() async {
-  let a = MyActor()
-  let closure = { print(a.klass) } // expected-typechecker-only-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
-  await transferToMain(closure)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
-  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-}
-
-func testSimpleLetClosureCaptureActorFieldThroughTuple() async {
-  let a = (MyActor(), 0)
-  let closure = { print(a.0.klass) } // expected-typechecker-only-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
-  await transferToMain(closure)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
-  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-}
-
-func testSimpleLetClosureCaptureActorFieldThroughOptional() async {
-  let a: MyActor? = MyActor()
-  let closure = { print(a!.klass) } // expected-typechecker-only-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
-  await transferToMain(closure)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
-  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-}
-
-#endif
-
 func testSimpleVarClosureCaptureActor() async {
   let a = MyActor()
   var closure = {}
   closure = { print(a) }
-  await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
   // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 }
 
-#if TYPECHECKER_ONLY
-
-func testSimpleVarClosureCaptureActorField() async {
-  let a = MyActor()
-  var closure = {}
-  closure = { print(a.klass) } // expected-typechecker-only-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
-  await transferToMain(closure)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
-  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-}
-
-func testSimpleVarClosureCaptureActorFieldThroughTuple() async {
-  let a = (MyActor(), 0)
-  var closure = {}
-  closure = { print(a.0.klass) } // expected-typechecker-only-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
-  await transferToMain(closure)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
-  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-}
-
-func testSimpleVarClosureCaptureActorFieldThroughOptional() async {
-  let a: MyActor? = MyActor()
-  var closure = {}
-  closure = { print(a!.klass) } // expected-typechecker-only-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
-  await transferToMain(closure)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
-  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-}
-
-#endif
 
 extension MyActor {
   // Make sure that we properly propagate actor derived from klass into field's
@@ -523,10 +450,10 @@ extension MyActor {
     let closure: () -> () = {
       print(f)
     }
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 
   // Make sure that we properly propagate actor derived from klass into field's
@@ -536,10 +463,10 @@ extension MyActor {
     let closure: () -> () = {
       print(f.field!)
     }
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
   }
 }
 
@@ -550,27 +477,27 @@ extension MyActor {
     }
 
     // This should error.
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'self'-isolated 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
 
     // This doesnt since we re-assign
     closure = {}
     await transferToMain(closure)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
     // This re-assignment shouldn't error.
     closure = {}
     // But this transfer should.
-    await transferToMain(closure) // expected-complete-warning {{passing argument of non-sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    await transferToMain(closure) // expected-complete-warning {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
     // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-    // expected-tns-warning @-2 {{sending 'closure' risks causing data races}}
-    // expected-tns-note @-3 {{sending 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local actor-isolated uses}}
+    // expected-warning @-2 {{sending 'closure' risks causing data races}}
+    // expected-note @-3 {{sending 'closure' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local actor-isolated uses}}
 
     // But this will error since we race.
-    closure() // expected-tns-note {{access can happen concurrently}}
+    closure() // expected-note {{access can happen concurrently}}
   }
 }
 
@@ -588,23 +515,23 @@ func testConversionsAndSendable(a: MyActor, f: @Sendable () -> Void, f2: () -> V
   await a.useNonSendableFunction(f)
 
   // Show that we error if we are not sendable.
-  await a.useNonSendableFunction(f2) // expected-complete-warning {{passing argument of non-sendable type '() -> Void' into actor-isolated context may introduce data races}}
+  await a.useNonSendableFunction(f2) // expected-complete-warning {{passing argument of non-Sendable type '() -> Void' into actor-isolated context may introduce data races}}
   // expected-complete-note @-1 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
-  // expected-tns-warning @-2 {{sending 'f2' risks causing data races}}
-  // expected-tns-note @-3 {{sending task-isolated 'f2' to actor-isolated instance method 'useNonSendableFunction' risks causing data races between actor-isolated and task-isolated uses}}
+  // expected-warning @-2 {{sending 'f2' risks causing data races}}
+  // expected-note @-3 {{sending task-isolated 'f2' to actor-isolated instance method 'useNonSendableFunction' risks causing data races between actor-isolated and task-isolated uses}}
 }
 
 func testSendableClosureCapturesNonSendable(a: MyActor) {
   let klass = NonSendableKlass()
   let _ = { @Sendable in
-    _ = klass // expected-warning {{capture of 'klass' with non-sendable type 'NonSendableKlass' in a '@Sendable' closure}}
+    _ = klass // expected-warning {{capture of 'klass' with non-Sendable type 'NonSendableKlass' in a '@Sendable' closure}}
   }
 }
 
 func testSendableClosureCapturesNonSendable2(a: FinalMainActorIsolatedKlass) {
   let klass = NonSendableKlass()
   let _ = { @Sendable @MainActor in
-    a.klass = klass // expected-complete-warning {{capture of 'klass' with non-sendable type 'NonSendableKlass' in a '@Sendable' closure}}
+    a.klass = klass // expected-complete-warning {{capture of 'klass' with non-Sendable type 'NonSendableKlass' in a '@Sendable' closure}}
   }
 }
 
@@ -618,7 +545,7 @@ func singleFieldVarMergeTest() async {
 
   // This transfers the entire region.
   await transferToMain(box.k)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   // But since box has only a single element, this doesn't race.
   box.k = NonSendableKlass()
@@ -627,7 +554,7 @@ func singleFieldVarMergeTest() async {
 
   // We transfer the box back to main.
   await transferToMain(box)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'SingleFieldKlassBox' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'SingleFieldKlassBox' into main actor-isolated context may introduce data races}}
 
   // And reassign over the entire box, so again we can use it again.
   box = SingleFieldKlassBox()
@@ -635,14 +562,14 @@ func singleFieldVarMergeTest() async {
   useValue(box)
   useValue(box.k)
 
-  await transferToMain(box) // expected-tns-warning {{sending 'box' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'box' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'SingleFieldKlassBox' into main actor-isolated context may introduce data races}}
+  await transferToMain(box) // expected-warning {{sending 'box' risks causing data races}}
+  // expected-note @-1 {{sending 'box' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'SingleFieldKlassBox' into main actor-isolated context may introduce data races}}
 
 
   // But if we use box.k here, we emit an error since we didn't reinitialize at
   // all.
-  useValue(box.k) // expected-tns-note {{access can happen concurrently}}
+  useValue(box.k) // expected-note {{access can happen concurrently}}
 }
 
 func multipleFieldVarMergeTest1() async {
@@ -650,13 +577,13 @@ func multipleFieldVarMergeTest1() async {
   box = TwoFieldKlassBox()
 
   // This transfers the entire region.
-  await transferToMain(box.k1) // expected-tns-warning {{sending 'box.k1' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'box.k1' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  await transferToMain(box.k1) // expected-warning {{sending 'box.k1' risks causing data races}}
+  // expected-note @-1 {{sending 'box.k1' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
 
   // So even if we reassign over k1, since we did a merge, this should error.
-  box.k1 = NonSendableKlass() // expected-tns-note {{access can happen concurrently}}
+  box.k1 = NonSendableKlass() // expected-note {{access can happen concurrently}}
   useValue(box)
 }
 
@@ -666,7 +593,7 @@ func multipleFieldVarMergeTest2() async {
 
   // This transfers the entire region.
   await transferToMain(box.k1)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   // But if we assign over box completely, we can use it again.
   box = TwoFieldKlassBox()
@@ -676,7 +603,7 @@ func multipleFieldVarMergeTest2() async {
   useValue(box)
 
   await transferToMain(box.k2)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   // But if we assign over box completely, we can use it again.
   box = TwoFieldKlassBox()
@@ -691,12 +618,12 @@ func multipleFieldTupleMergeTest1() async {
   box = (NonSendableKlass(), NonSendableKlass())
 
   // This transfers the entire region.
-  await transferToMain(box.0) // expected-tns-warning {{sending 'box.0' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'box.0' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  await transferToMain(box.0) // expected-warning {{sending 'box.0' risks causing data races}}
+  // expected-note @-1 {{sending 'box.0' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   // So even if we reassign over k1, since we did a merge, this should error.
-  box.0 = NonSendableKlass() // expected-tns-note {{access can happen concurrently}}
+  box.0 = NonSendableKlass() // expected-note {{access can happen concurrently}}
   useValue(box)
 }
 
@@ -708,7 +635,7 @@ func multipleFieldTupleMergeTest2() async {
 
   // This transfers the entire region.
   await transferToMain(box.0)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   let box2 = (NonSendableKlass(), NonSendableKlass())
   // But if we assign over box completely, we can use it again.
@@ -719,7 +646,7 @@ func multipleFieldTupleMergeTest2() async {
   useValue(box)
 
   await transferToMain(box.1)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   // But if we assign over box completely, we can use it again.
   box = (NonSendableKlass(), NonSendableKlass())
@@ -744,56 +671,56 @@ class ClassFieldTests { // expected-complete-note 6{{}}
 
 func letSendableTrivialClassFieldTest() async {
   let test = ClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
   _ = test.letSendableTrivial
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func letSendableNonTrivialClassFieldTest() async {
   let test = ClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
 
   _ = test.letSendableNonTrivial
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func letNonSendableNonTrivialClassFieldTest() async {
   let test = ClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.letNonSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.letNonSendableNonTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func varSendableTrivialClassFieldTest() async {
   let test = ClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.varSendableTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.varSendableTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func varSendableNonTrivialClassFieldTest() async {
   let test = ClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.varSendableNonTrivial  // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.varSendableNonTrivial  // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func varNonSendableNonTrivialClassFieldTest() async {
   let test = ClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.varNonSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'ClassFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.varNonSendableNonTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
@@ -812,55 +739,55 @@ final class FinalClassFieldTests { // expected-complete-note 6 {{}}
 
 func letSendableTrivialFinalClassFieldTest() async {
   let test = FinalClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
   _ = test.letSendableTrivial
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func letSendableNonTrivialFinalClassFieldTest() async {
   let test = FinalClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
   _ = test.letSendableNonTrivial
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func letNonSendableNonTrivialFinalClassFieldTest() async {
   let test = FinalClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.letNonSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.letNonSendableNonTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func varSendableTrivialFinalClassFieldTest() async {
   let test = FinalClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.varSendableTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.varSendableTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func varSendableNonTrivialFinalClassFieldTest() async {
   let test = FinalClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.varSendableNonTrivial  // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.varSendableNonTrivial  // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func varNonSendableNonTrivialFinalClassFieldTest() async {
   let test = FinalClassFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.varNonSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'FinalClassFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.varNonSendableNonTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
@@ -879,28 +806,28 @@ struct StructFieldTests { // expected-complete-note 31 {{}}
 
 func letSendableTrivialLetStructFieldTest() async {
   let test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.letSendableTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.letSendableTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func letSendableNonTrivialLetStructFieldTest() async {
   let test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.letSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.letSendableNonTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func letNonSendableNonTrivialLetStructFieldTest() async {
   let test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  let z = test.letNonSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  let z = test.letNonSendableNonTrivial // expected-note {{access can happen concurrently}}
   _ = z
   useValue(test)
 }
@@ -908,30 +835,30 @@ func letNonSendableNonTrivialLetStructFieldTest() async {
 func letSendableTrivialVarStructFieldTest() async {
   var test = StructFieldTests()
   test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   _ = test.letSendableTrivial
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func letSendableNonTrivialVarStructFieldTest() async {
   var test = StructFieldTests()
   test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   _ = test.letSendableNonTrivial
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func letNonSendableNonTrivialVarStructFieldTest() async {
   var test = StructFieldTests()
   test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  let z = test.letNonSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  let z = test.letNonSendableNonTrivial // expected-note {{access can happen concurrently}}
   _ = z
   useValue(test)
 }
@@ -948,10 +875,10 @@ func letNonSendableNonTrivialLetStructFieldClosureTest() async {
     print(test)
   }
   _ = cls2
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  let z = test.letSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  let z = test.letSendableNonTrivial // expected-note {{access can happen concurrently}}
   _ = z
   let z2 = test.varSendableNonTrivial
   _ = z2
@@ -960,28 +887,28 @@ func letNonSendableNonTrivialLetStructFieldClosureTest() async {
 
 func varSendableTrivialLetStructFieldTest() async {
   let test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.varSendableTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.varSendableTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func varSendableNonTrivialLetStructFieldTest() async {
   let test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  _ = test.varSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  _ = test.varSendableNonTrivial // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
 func varNonSendableNonTrivialLetStructFieldTest() async {
   let test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  let z = test.varNonSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  let z = test.varNonSendableNonTrivial // expected-note {{access can happen concurrently}}
   _ = z
   useValue(test)
 }
@@ -989,30 +916,30 @@ func varNonSendableNonTrivialLetStructFieldTest() async {
 func varSendableTrivialVarStructFieldTest() async {
   var test = StructFieldTests()
   test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   _ = test.varSendableTrivial
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func varSendableNonTrivialVarStructFieldTest() async {
   var test = StructFieldTests()
   test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   _ = test.varSendableNonTrivial
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func varNonSendableNonTrivialVarStructFieldTest() async {
   var test = StructFieldTests()
   test = StructFieldTests()
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  let z = test.varNonSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  let z = test.varNonSendableNonTrivial // expected-note {{access can happen concurrently}}
   _ = z
   useValue(test)
 }
@@ -1025,10 +952,10 @@ func varNonSendableNonTrivialLetStructFieldClosureTest1() async {
     test = StructFieldTests()
   }
   _ = cls
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  let z = test.letSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  let z = test.letSendableNonTrivial // expected-note {{access can happen concurrently}}
   _ = z
   useValue(test)
 }
@@ -1040,10 +967,10 @@ func varNonSendableNonTrivialLetStructFieldClosureTest2() async {
     test = StructFieldTests()
   }
   _ = cls
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  let z = test.varSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  let z = test.varSendableNonTrivial // expected-note {{access can happen concurrently}}
   _ = z
   useValue(test)
 }
@@ -1055,10 +982,10 @@ func varNonSendableNonTrivialLetStructFieldClosureTest3() async {
     test = StructFieldTests()
   }
   _ = cls
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  test.varSendableNonTrivial = SendableKlass() // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  test.varSendableNonTrivial = SendableKlass() // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
@@ -1071,10 +998,10 @@ func varNonSendableNonTrivialLetStructFieldClosureTest4() async {
     test = StructFieldTests()
   }
   _ = cls
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  let z = test.letSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  let z = test.letSendableNonTrivial // expected-note {{access can happen concurrently}}
   _ = z
   useValue(test)
 }
@@ -1087,10 +1014,10 @@ func varNonSendableNonTrivialLetStructFieldClosureTest5() async {
     test = StructFieldTests()
   }
   _ = cls
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  let z = test.varSendableNonTrivial // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  let z = test.varSendableNonTrivial // expected-note {{access can happen concurrently}}
   _ = z
   useValue(test)
 }
@@ -1103,10 +1030,10 @@ func varNonSendableNonTrivialLetStructFieldClosureTest6() async {
     test = StructFieldTests()
   }
   _ = cls
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  test.varSendableNonTrivial = SendableKlass() // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  test.varSendableNonTrivial = SendableKlass() // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
@@ -1118,10 +1045,10 @@ func varNonSendableNonTrivialLetStructFieldClosureTest7() async {
     test.varSendableNonTrivial = SendableKlass()
   }
   _ = cls
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  test.varSendableNonTrivial = SendableKlass() // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  test.varSendableNonTrivial = SendableKlass() // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
@@ -1133,10 +1060,10 @@ func varNonSendableNonTrivialLetStructFieldClosureTest8() async {
     useInOut(&test)
   }
   _ = cls
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  test.varSendableNonTrivial = SendableKlass() // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  test.varSendableNonTrivial = SendableKlass() // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
@@ -1148,10 +1075,10 @@ func varNonSendableNonTrivialLetStructFieldClosureTest9() async {
     useInOut(&test.varSendableNonTrivial)
   }
   _ = cls
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
-  test.varSendableNonTrivial = SendableKlass() // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+  test.varSendableNonTrivial = SendableKlass() // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
@@ -1166,14 +1093,14 @@ func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive1() async {
     }
     _ = cls
   } else {
-    await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+    await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+    // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
 
     test.varSendableNonTrivial = SendableKlass()
   }
 
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive2() async {
@@ -1187,12 +1114,12 @@ func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive2() async {
     }
     _ = cls
 
-    await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+    await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+    // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   }
 
-  test.varSendableNonTrivial = SendableKlass() // expected-tns-note {{access can happen concurrently}}
+  test.varSendableNonTrivial = SendableKlass() // expected-note {{access can happen concurrently}}
   useValue(test)
 }
 
@@ -1209,13 +1136,13 @@ func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive3() async {
     }
     _ = cls
   } else {
-    await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+    await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+    // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   }
 
   test.varSendableNonTrivial = SendableKlass()
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive4() async {
@@ -1229,9 +1156,9 @@ func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive4() async {
     // loop carry use and an error due to multiple params. Then we could emit
     // the error on test below. This is still correct though, just not as
     // good... that is QoI though.
-    await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-tns-note @-2 {{access can happen concurrently}}
+    await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+    // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-note @-2 {{access can happen concurrently}}
 
     // This is treated as a use since test is in box form and is mutable. So we
     // treat assignment as a merge.
@@ -1258,10 +1185,10 @@ func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive5() async {
   // this. This is a case where we are going to need to be able to have the
   // compiler explain the regions well.
   for _ in 0..<1024 {
-    await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-tns-note @-2 {{access can happen concurrently}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+    await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-note @-2 {{access can happen concurrently}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
     test = StructFieldTests()
   }
 
@@ -1282,17 +1209,17 @@ func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive6() async {
       useInOut(&test.varSendableNonTrivial)
     }
     _ = cls
-    await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+    await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   } else {
-    await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+    await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   }
 
-  test.varSendableNonTrivial = SendableKlass() // expected-tns-note {{access can happen concurrently}}
-  useValue(test)  // expected-tns-note {{access can happen concurrently}}
+  test.varSendableNonTrivial = SendableKlass() // expected-note {{access can happen concurrently}}
+  useValue(test)  // expected-note {{access can happen concurrently}}
 }
 
 // In this case since we are tracking the transfer from the else statement, we
@@ -1303,21 +1230,21 @@ func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive7() async {
   var cls = {}
 
   if await booleanFlag {
-    await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+    await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   } else {
     cls = {
       useInOut(&test.varSendableNonTrivial)
     }
     _ = cls
-    await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
+    await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'StructFieldTests' into main actor-isolated context may introduce data races}}
   }
 
-  test.varSendableNonTrivial = SendableKlass() // expected-tns-note {{access can happen concurrently}}
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  test.varSendableNonTrivial = SendableKlass() // expected-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 ////////////////////////////
@@ -1326,30 +1253,30 @@ func varNonSendableNonTrivialLetStructFieldClosureFlowSensitive7() async {
 
 func varSendableTrivialLetTupleFieldTest() async {
   let test = (0, SendableKlass(), NonSendableKlass())
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
   let z = test.0
   useValue(z)
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func varSendableNonTrivialLetTupleFieldTest() async {
   let test = (0, SendableKlass(), NonSendableKlass())
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
   let z = test.1
   useValue(z)
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func varNonSendableNonTrivialLetTupleFieldTest() async {
   let test = (0, SendableKlass(), NonSendableKlass())
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
-  let z = test.2 // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
+  let z = test.2 // expected-note {{access can happen concurrently}}
   useValue(z)
   useValue(test)
 }
@@ -1357,40 +1284,40 @@ func varNonSendableNonTrivialLetTupleFieldTest() async {
 func varSendableTrivialVarTupleFieldTest() async {
   var test = (0, SendableKlass(), NonSendableKlass())
   test = (0, SendableKlass(), NonSendableKlass())
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
   _ = test.0
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func varSendableTrivialVarTupleFieldTest2() async {
   var test = (0, SendableKlass(), NonSendableKlass())
   test = (0, SendableKlass(), NonSendableKlass())
-  await transferToMain(test.2) // expected-tns-warning {{sending 'test.2' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test.2' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  await transferToMain(test.2) // expected-warning {{sending 'test.2' risks causing data races}}
+  // expected-note @-1 {{sending 'test.2' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   _ = test.0
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func varSendableNonTrivialVarTupleFieldTest() async {
   var test = (0, SendableKlass(), NonSendableKlass())
   test = (0, SendableKlass(), NonSendableKlass())
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
   _ = test.1
-  useValue(test) // expected-tns-note {{access can happen concurrently}}
+  useValue(test) // expected-note {{access can happen concurrently}}
 }
 
 func varNonSendableNonTrivialVarTupleFieldTest() async {
   var test = (0, SendableKlass(), NonSendableKlass())
   test = (0, SendableKlass(), NonSendableKlass())
-  await transferToMain(test) // expected-tns-warning {{sending 'test' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
-  let z = test.2 // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(test) // expected-warning {{sending 'test' risks causing data races}}
+  // expected-note @-1 {{sending 'test' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type '(Int, SendableKlass, NonSendableKlass)' into main actor-isolated context may introduce data races}}
+  let z = test.2 // expected-note {{access can happen concurrently}}
   useValue(z)
   useValue(test)
 }
@@ -1403,16 +1330,16 @@ func controlFlowTest1() async {
   let x = NonSendableKlass()
 
   if await booleanFlag {
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   } else {
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 
-  useValue(x) // expected-tns-note 2{{access can happen concurrently}}
+  useValue(x) // expected-note 2{{access can happen concurrently}}
 }
 
 // This test seems like something that we should not error upon. What is
@@ -1427,10 +1354,10 @@ func controlFlowTest2() async {
   var x = NonSendableKlass()
 
   for _ in 0..<1024 {
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-tns-note @-2 {{access can happen concurrently}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-note @-2 {{access can happen concurrently}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     x = NonSendableKlass()
   }
@@ -1452,46 +1379,33 @@ actor ActorWithSetter {
   func test1() async {
     let x = NonSendableKlass()
     self.field = x
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 
   func test2() async {
     let x = NonSendableKlass()
     self.twoFieldBox.k1 = x
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 
   func test3() async {
     let x = NonSendableKlass()
     self.twoFieldBoxInTuple.1.k1 = x
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  }
-
-  // This triggers a crash in SILGen with tns enabled.
-  #if TYPECHECKER_ONLY
-  func recursive() async {
-    let x = NonSendableKlass()
-    await self.recursive!.twoFieldBoxInTuple.1.k2 = x
-    // expected-typechecker-only-warning @-1 {{non-sendable type '(NonSendableKlass, TwoFieldKlassBox)' of property 'twoFieldBoxInTuple' cannot exit actor-isolated context}}
-    // expected-typechecker-only-warning @-2 {{non-sendable type '(NonSendableKlass, TwoFieldKlassBox)' of property 'twoFieldBoxInTuple' cannot exit actor-isolated context}}
-
-    await transferToMain(x) // xpected-tns-warning {{call site passes `self` or a non-sendable argument of this function to another thread, potentially yielding a race with the caller}}
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
-  #endif
 
   func classBox() async {
     let x = NonSendableKlass()
     self.classBox.k1 = x
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 }
 
@@ -1505,59 +1419,46 @@ final actor FinalActorWithSetter {
   func test1() async {
     let x = NonSendableKlass()
     self.field = x
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 
   func test2() async {
     let x = NonSendableKlass()
     self.twoFieldBox.k1 = x
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 
   func test3() async {
     let x = NonSendableKlass()
     self.twoFieldBoxInTuple.1.k1 = x
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  }
-
-  // This triggers a crash in SILGen with tns enabled.
-  #if TYPECHECKER_ONLY
-  func recursive() async {
-    let x = NonSendableKlass()
-    await self.recursive!.twoFieldBoxInTuple.1.k2 = x
-    // expected-typechecker-only-warning @-1 {{non-sendable type '(NonSendableKlass, TwoFieldKlassBox)' of property 'twoFieldBoxInTuple' cannot exit actor-isolated context}}
-    // expected-typechecker-only-warning @-2 {{non-sendable type '(NonSendableKlass, TwoFieldKlassBox)' of property 'twoFieldBoxInTuple' cannot exit actor-isolated context}}
-
-    await transferToMain(x) // xpected-tns-warning {{call site passes `self` or a non-sendable argument of this function to another thread, potentially yielding a race with the caller}}
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
-  #endif
 
   func classBox() async {
     let x = NonSendableKlass()
     self.classBox.k1 = x
-    await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 }
 
 func functionArgumentIntoClosure(_ x: @escaping () -> ()) async {
   let _ = { @MainActor in
-    let _ = x // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{task-isolated 'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
-    // expected-complete-warning @-2 {{capture of 'x' with non-sendable type '() -> ()' in a '@Sendable' closure}}
+    let _ = x // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{task-isolated 'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+    // expected-complete-warning @-2 {{capture of 'x' with non-Sendable type '() -> ()' in a '@Sendable' closure}}
     // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
   }
 }
 
-// Make sure we handle the merge of the actor isolated and disconnected state
+// Make sure we handle the merge of the actor-isolated and disconnected state
 // appropriately.
 //
 // TODO: Since we are accessing the var field, we miss an
@@ -1566,9 +1467,13 @@ func functionArgumentIntoClosure(_ x: @escaping () -> ()) async {
   let a = MainActorIsolatedKlass()
   var c = NonSendableKlass()
   for _ in 0..<1024 {
-    await useValueAsync(c) // expected-tns-warning {{sending 'c' risks causing data races}}
-    // expected-tns-note @-1 {{sending main actor-isolated 'c' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' outside of main actor-isolated context may introduce data races}}
+    // This works with nonisolated(nonsending) since the first time through the
+    // loop we are disconnected... meaning that we are ok. The second time
+    // through the loop, we are now main actor isolated, but again b/c we
+    // inherit isolation, we are ok.
+    await useValueAsync(c) // expected-ni-warning {{sending 'c' risks causing data races}}
+    // expected-ni-note @-1 {{sending main actor-isolated 'c' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' outside of main actor-isolated context may introduce data races}}
     c = a.klass
   }
 }
@@ -1577,9 +1482,9 @@ func functionArgumentIntoClosure(_ x: @escaping () -> ()) async {
   let a = MainActorIsolatedKlass()
   var c = NonSendableKlass()
   for _ in 0..<1024 {
-    await useValueAsync(c) // expected-tns-warning {{sending 'c' risks causing data races}}
-    // expected-tns-note @-1 {{sending main actor-isolated 'c' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' outside of main actor-isolated context may introduce data races}}
+    await useValueAsync(c) // expected-ni-warning {{sending 'c' risks causing data races}}
+    // expected-ni-note @-1 {{sending main actor-isolated 'c' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' outside of main actor-isolated context may introduce data races}}
     c = a.klassLet
   }
 }
@@ -1587,25 +1492,25 @@ func functionArgumentIntoClosure(_ x: @escaping () -> ()) async {
 func testGetActorName() async {
   let a = MyActor()
   let x = NonSendableKlass()
-  await a.useKlass(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'x' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
-  useValue(x) // expected-tns-note {{access can happen concurrently}}
+  await a.useKlass(x) // expected-warning {{sending 'x' risks causing data races}}
+  // expected-note @-1 {{sending 'x' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
+  useValue(x) // expected-note {{access can happen concurrently}}
 }
 
 extension MyActor {
   func testCallBangIsolatedMethod(other: MyActor) async {
-    await klass.asyncCallWithIsolatedParameter(isolation: other) // expected-tns-warning {{sending 'self.klass' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'self.klass' to actor-isolated instance method 'asyncCallWithIsolatedParameter(isolation:)' risks causing data races between actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
+    await klass.asyncCallWithIsolatedParameter(isolation: other) // expected-warning {{sending 'self.klass' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'self.klass' to actor-isolated instance method 'asyncCallWithIsolatedParameter(isolation:)' risks causing data races between actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
   }
 }
 
 extension FinalActor {
   func testCallBangIsolatedMethod(other: MyActor) async {
-    await klass.asyncCallWithIsolatedParameter(isolation: other) // expected-tns-warning {{sending 'self.klass' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'self.klass' to actor-isolated instance method 'asyncCallWithIsolatedParameter(isolation:)' risks causing data races between actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
+    await klass.asyncCallWithIsolatedParameter(isolation: other) // expected-warning {{sending 'self.klass' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'self.klass' to actor-isolated instance method 'asyncCallWithIsolatedParameter(isolation:)' risks causing data races between actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
   }
 }
 
@@ -1616,17 +1521,17 @@ extension NonSendableKlass {
 
 extension MyActor {
   func testCallBangIsolatedDirectMethod(other: MyActor) async {
-    await klass.directAsyncCallWithIsolatedParameter(isolation: other) // expected-tns-warning {{sending 'self.klass' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'self.klass' to actor-isolated instance method 'directAsyncCallWithIsolatedParameter(isolation:)' risks causing data races between actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
+    await klass.directAsyncCallWithIsolatedParameter(isolation: other) // expected-warning {{sending 'self.klass' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'self.klass' to actor-isolated instance method 'directAsyncCallWithIsolatedParameter(isolation:)' risks causing data races between actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
   }
 }
 
 extension FinalActor {
   func testCallBangIsolatedDirectMethod(other: MyActor) async {
-    await klass.directAsyncCallWithIsolatedParameter(isolation: other) // expected-tns-warning {{sending 'self.klass' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'self.klass' to actor-isolated instance method 'directAsyncCallWithIsolatedParameter(isolation:)' risks causing data races between actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
+    await klass.directAsyncCallWithIsolatedParameter(isolation: other) // expected-warning {{sending 'self.klass' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'self.klass' to actor-isolated instance method 'directAsyncCallWithIsolatedParameter(isolation:)' risks causing data races between actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
   }
 }
 
@@ -1654,9 +1559,9 @@ extension MyActor {
       let x = NonSendableKlass()
       self.useKlass(x)
       await transferToMain(x)
-      // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-      // expected-tns-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-      // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+      // expected-warning @-1 {{sending 'x' risks causing data races}}
+      // expected-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+      // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     }
   }
 }
@@ -1715,11 +1620,11 @@ func initAccessorTests() {
 func differentInstanceTest(_ a: MyActor, _ b: MyActor) async {
   let x = NonSendableKlass()
   await a.useKlass(x)
-  // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'x' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
-  await b.useKlass(x) // expected-tns-note {{access can happen concurrently}}
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'x' risks causing data races}}
+  // expected-note @-2 {{sending 'x' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
+  await b.useKlass(x) // expected-note {{access can happen concurrently}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into actor-isolated context may introduce data races}}
 }
 
 protocol AssociatedTypeTestProtocol {
@@ -1730,30 +1635,30 @@ func associatedTypeTestBasic<T: AssociatedTypeTestProtocol>(_: T, _: isolated T.
 }
 
 func associatedTypeTestBasic2<T: AssociatedTypeTestProtocol>(_: T, iso: isolated T.A, x: NonSendableKlass) async {
-  await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'iso'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'iso'-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+  // expected-note @-1 {{sending 'iso'-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and 'iso'-isolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 }
 
 func sendableGlobalActorIsolated() {
   let x = NonSendableKlass()
   let _ = { @Sendable @MainActor in
-    print(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-    // expected-tns-note @-1 {{'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
-    // expected-complete-warning @-2 {{capture of 'x' with non-sendable type 'NonSendableKlass' in a '@Sendable' closure}}
+    print(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+    // expected-complete-warning @-2 {{capture of 'x' with non-Sendable type 'NonSendableKlass' in a '@Sendable' closure}}
   }
-  print(x) // expected-tns-note {{access can happen concurrently}}
+  print(x) // expected-note {{access can happen concurrently}}
 }
 
-// We do not get an error here since we are transferring x both times to a main
-// actor isolated thing function. We used to emit an error when using region
+// We do not get an error here since we are transferring x both times to a
+// MainActor-isolated thing function. We used to emit an error when using region
 // isolation since we would trip on the store_borrow we used to materialize the
 // value.
 func testIndirectParameterSameIsolationNoError() async {
   let x = NonSendableKlass()
-  await transferToMain(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  await transferToMain(x) // expected-tns-note {{access can happen concurrently}}
+  await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  await transferToMain(x) // expected-note {{access can happen concurrently}}
 }
 
 extension MyActor {
@@ -1766,12 +1671,12 @@ extension MyActor {
         _ = self
         _ = sc
 
-        Task { // expected-tns-warning {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
-          // expected-tns-note @-1 {{Passing value of non-Sendable type '() async -> ()' as a 'sending' argument to initializer 'init(priority:operation:)' risks causing races in between local and caller code}}
+        Task { // expected-warning {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
+          // expected-note @-1 {{Passing value of non-Sendable type '() async -> ()' as a 'sending' argument to initializer 'init(name:priority:operation:)' risks causing races in between local and caller code}}
           _ = sc
         }
 
-        Task { // expected-tns-note {{access can happen concurrently}}
+        Task { // expected-note {{access can happen concurrently}}
           _ = sc
         }
       }
@@ -1826,8 +1731,8 @@ actor FunctionWithSendableResultAndIsolationActor {
 @MainActor
 func previouslyBrokenTestCase(ns: NonSendableKlass) async -> SendableGenericStruct? {
   return await { () -> SendableGenericStruct? in
-    return await ns.getSendableGenericStructAsync() // expected-tns-warning {{sending 'ns' risks causing data races}}
-    // expected-tns-note @-1 {{sending main actor-isolated 'ns' to nonisolated instance method 'getSendableGenericStructAsync()' risks causing data races between nonisolated and main actor-isolated uses}}
+    return await ns.getSendableGenericStructAsync() // expected-ni-warning {{sending 'ns' risks causing data races}}
+    // expected-ni-note @-1 {{sending main actor-isolated 'ns' to nonisolated instance method 'getSendableGenericStructAsync()' risks causing data races between nonisolated and main actor-isolated uses}}
   }()
 }
 
@@ -1836,7 +1741,7 @@ func testThatGlobalActorTakesPrecedenceOverActorIsolationOnMethods() async {
   let a = MyActor()
   let ns = NonSendableKlass()
 
-  // 'ns' should be main actor isolated since useKlassMainActor is @MainActor
+  // 'ns' should be MainActor isolated since useKlassMainActor is @MainActor
   // isolated. Previously we would let MyActor take precedence here...
   a.useKlassMainActor(ns)
 
@@ -1865,15 +1770,15 @@ public class Context {
 
 extension MyActor {
   public func withContext<T>(_ block: sending (NonSendableKlass) throws -> T) async throws -> sending T {
-    return try block(klass) // expected-tns-warning {{returning 'self'-isolated 'self.klass' as a 'sending' result risks causing data races}}
-    // expected-tns-note @-1 {{returning 'self'-isolated 'self.klass' risks causing data races since the caller assumes that 'self.klass' can be safely sent to other isolation domains}}
+    return try block(klass) // expected-warning {{returning 'self'-isolated 'self.klass' as a 'sending' result risks causing data races}}
+    // expected-note @-1 {{returning 'self'-isolated 'self.klass' risks causing data races since the caller assumes that 'self.klass' can be safely sent to other isolation domains}}
   }
 }
 
 func nonSendableAllocBoxConsumingParameter(x: consuming SendableKlass) async throws {
   try await withThrowingTaskGroup(of: Void.self) { group in
-    group.addTask { // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
-      useValue(x) // expected-tns-note {{closure captures reference to mutable parameter 'x' which is accessible to code in the current task}}
+    group.addTask { // expected-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
+      useValue(x) // expected-note {{closure captures reference to mutable parameter 'x' which is accessible to code in the current task}}
     }
 
     try await group.waitForAll()
@@ -1885,8 +1790,8 @@ func nonSendableAllocBoxConsumingVar() async throws {
   x = SendableKlass()
 
   try await withThrowingTaskGroup(of: Void.self) { group in
-    group.addTask { // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
-      useValue(x) // expected-tns-note {{closure captures reference to mutable var 'x' which is accessible to code in the current task}}
+    group.addTask { // expected-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
+      useValue(x) // expected-note {{closure captures reference to mutable var 'x' which is accessible to code in the current task}}
     }
 
     try await group.waitForAll()
@@ -1904,8 +1809,8 @@ func offByOneWithImplicitPartialApply() {
       func b() {
           let asdf = ""
           Task { @MainActor in
-            a.description = asdf // expected-tns-warning {{sending 'self' risks causing data races}}
-            // expected-tns-note @-1 {{task-isolated 'self' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+            a.description = asdf // expected-warning {{sending 'self' risks causing data races}}
+            // expected-note @-1 {{task-isolated 'self' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
           }
       }
   }
@@ -1943,8 +1848,8 @@ func testIndirectAndDirectSendingResultsWithGlobalActor() async {
 func testFunctionIsNotEmpty(input: SendableKlass) async throws {
   var result: [SendableKlass] = []
   try await withThrowingTaskGroup(of: Void.self) { taskGroup in // expected-warning {{no calls to throwing functions occur within 'try' expression}}
-    taskGroup.addTask { // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
-      result.append(input) // expected-tns-note {{closure captures reference to mutable var 'result' which is accessible to code in the current task}}
+    taskGroup.addTask { // expected-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
+      result.append(input) // expected-note {{closure captures reference to mutable var 'result' which is accessible to code in the current task}}
     }
   }
 }
@@ -1964,7 +1869,135 @@ extension NonIsolatedFinalKlass {
   // We used to crash while computing the isolation of the ref_element_addr
   // here. Make sure we do not crash.
   func testGetIsolationInfoOfField() async {
-    await transferToMain(ns) // expected-tns-warning {{sending 'self.ns' risks causing data races}}
-    // expected-tns-note @-1 {{sending task-isolated 'self.ns' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and task-isolated uses}}
+    await transferToMain(ns) // expected-warning {{sending 'self.ns' risks causing data races}}
+    // expected-note @-1 {{sending task-isolated 'self.ns' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and task-isolated uses}}
+  }
+}
+
+func mutableLocalCaptureDataRace() async {
+  var x = 0
+  x = 0
+  _ = x
+
+  Task.detached { x = 1 } // expected-warning {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
+  // expected-note @-1 {{Passing value of non-Sendable type '() async -> ()' as a 'sending' argument to static method 'detached(name:priority:operation:)' risks causing races in between local and caller code}}
+
+  x = 2 // expected-note {{access can happen concurrently}}
+}
+
+func mutableLocalCaptureDataRace2() async {
+  var x = 0
+  x = 0
+
+  Task.detached { x = 1 } // expected-warning {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
+  // expected-note @-1 {{Passing value of non-Sendable type '() async -> ()' as a 'sending' argument to static method 'detached(name:priority:operation:)' risks causing races in between local and caller code}}
+
+  print(x) // expected-note {{access can happen concurrently}}
+}
+
+func localCaptureDataRace3() async {
+  let x = 0
+
+  Task.detached { print(x) }
+
+  print(x)
+}
+
+nonisolated func localCaptureDataRace4() {
+  var x = 0
+  _ = x
+
+  Task.detached { @MainActor in x = 1 } // expected-warning {{sending 'x' risks causing data races}}
+  // expected-note @-1 {{'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+
+  x = 2 // expected-note {{access can happen concurrently}}
+}
+
+// We shouldn't error here since every time around, we are using the same
+// isolation.
+func testIsolatedParamInference() {
+  class S : @unchecked Sendable {}
+
+  final class B {
+    var s = S()
+    var b: Bool = false
+
+    func foo(isolation: isolated Actor = #isolation) async {
+      while !b {
+        await withTaskGroup(of: Int.self) { group in
+          _ = isolation
+          self.s = S()
+        }
+      }
+    }
+  }
+}
+
+// We shouldn't error here since test2 is isolated to B since we are capturing
+// self and funcParam is also exposed to B's isolated since it is a parameter to
+// one of B's methods.
+func sendIsolatedValueToItsOwnIsolationDomain() {
+  class A {
+    func useValue() {}
   }
+
+  func helper(_ x: @escaping () -> A) {}
+
+  actor B {
+    let field = A()
+
+    private func test(funcParam: A?) async {
+      helper {
+        if let funcParam {
+          return funcParam
+        } else {
+          return self.field
+        }
+      }
+
+      funcParam?.useValue()
+    }
+  }
+}
+
+// We used to crash on this since we were not looking finding underlying objects
+// hard enough.
+func indirectEnumTestCase<T>(_ e: MyEnum<T>) async -> Bool {
+    switch e {
+    case .some(let x):
+      _ = x
+      return true
+    default:
+        return false
+    }
+}
+
+/// Make sure that we properly infer the location of the capture of self in func
+/// d().
+func inferLocationOfCapturedTaskIsolatedSelfCorrectly() {
+  class A {
+    var block:  @MainActor () -> Void = {}
+  }
+  class B {
+    let a = A()
+
+    func d() {
+      a.block = c // expected-warning {{converting non-Sendable function value to '@MainActor @Sendable () -> Void' may introduce data races}}
+      // expected-warning @-1 {{non-Sendable '@MainActor () -> ()'-typed result can not be returned from main actor-isolated function to nonisolated context}}
+      // expected-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+      // expected-warning @-3 {{sending 'self' risks causing data races}}
+      // expected-note @-4 {{task-isolated 'self' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+    }
+
+    @MainActor
+    func c() {}
+  }
+}
+
+nonisolated(nonsending) func testCallNonisolatedNonsending(_ x: NonSendableKlass) async {
+  await useValueAsync(x) // expected-ni-warning {{sending 'x' risks causing data races}}
+  // expected-ni-note @-1 {{sending nonisolated(nonsending) task-isolated 'x' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and nonisolated(nonsending) task-isolated uses}}
+  await useValueAsyncConcurrent(x) // expected-warning {{sending 'x' risks causing data races}}
+  // expected-ni-note @-1 {{sending nonisolated(nonsending) task-isolated 'x' to nonisolated global function 'useValueAsyncConcurrent' risks causing data races between nonisolated and nonisolated(nonsending) task-isolated uses}}
+  // expected-ni-ns-note @-2 {{sending task-isolated 'x' to @concurrent global function 'useValueAsyncConcurrent' risks causing data races between @concurrent and task-isolated uses}}
 }
diff --git a/test/Concurrency/transfernonsendable_asynclet.swift b/test/Concurrency/transfernonsendable_asynclet.swift
index 350353c05398b..f00bb44a5876b 100644
--- a/test/Concurrency/transfernonsendable_asynclet.swift
+++ b/test/Concurrency/transfernonsendable_asynclet.swift
@@ -1,13 +1,15 @@
-// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -verify-additional-prefix ni-
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault -verify-additional-prefix ni-ns-
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
 ////////////////////////
 
-/// Classes are always non-sendable, so this is non-sendable
+/// Classes are always non-Sendable, so this is non-Sendable
 class NonSendableKlass {
   // expected-note @-1 {{}}
   var field: NonSendableKlass? = nil
@@ -84,7 +86,8 @@ struct TwoFieldKlassBox {
 func asyncLet_Let_ActorIsolated_Simple1() async {
   let x = NonSendableKlass()
   async let y = transferToMainInt(x) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
   useValue(x) // expected-note {{access can happen concurrently}}
   let _ = await y
 }
@@ -92,7 +95,8 @@ func asyncLet_Let_ActorIsolated_Simple1() async {
 func asyncLet_Let_ActorIsolated_Simple2() async {
   let x = NonSendableKlass()
   async let y = transferToMainInt(x) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
 
   let _ = await y
@@ -102,7 +106,8 @@ func asyncLet_Let_ActorIsolated_Simple2() async {
 func asyncLet_Let_ActorIsolated_Simple3() async {
   let x = NonSendableKlass()
   async let y = transferToMainInt(x) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}  
 
   // TODO: We shouldn't emit the 2nd error here given the current implementation
   // since it is only accessible along the else path but we already hit
@@ -120,7 +125,8 @@ func asyncLet_Let_ActorIsolated_Simple3() async {
 func asyncLet_Let_ActorIsolated_Simple4() async {
   let x = NonSendableKlass()
   async let y = transferToMainInt(x) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   if await booleanFlag {
     useValue(x) // expected-note {{access can happen concurrently}}
@@ -133,7 +139,8 @@ func asyncLet_Let_ActorIsolated_Simple4() async {
 func asyncLet_Let_ActorIsolated_Simple5() async {
   let x = NonSendableKlass()
   async let y = transferToMainInt(x) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   if await booleanFlag {
     let _ = await y
@@ -148,7 +155,8 @@ func asyncLet_Let_ActorIsolated_Simple5() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsClass1() async {
   let x = NonSendableKlass()
   async let y = transferToMainInt(x.field) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -157,7 +165,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsClass1() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsClass2() async {
   let x = NonSendableKlass()
   async let y = transferToMainInt(x.field) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x.field) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -166,7 +175,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsClass2() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsClass3() async {
   let x = NonSendableKlass()
   async let y = transferToMainInt(x.field) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x.field2) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -177,7 +187,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsClass3() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsStruct1() async {
   let x = TwoFieldKlassBox()
   async let y = transferToMainInt(x.k1) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -186,7 +197,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsStruct1() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsStruct2() async {
   let x = TwoFieldKlassBox()
   async let y = transferToMainInt(x.k1) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x.k1) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -195,7 +207,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsStruct2() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsStruct3() async {
   let x = TwoFieldKlassBox()
   async let y = transferToMainInt(x.k1) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x.k2) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -204,7 +217,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsStruct3() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsStruct4() async {
   let x = TwoFieldKlassBox()
   async let y = transferToMainInt(x.k2.field2) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x.k1.field) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -215,7 +229,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsStruct4() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsTuple1() async {
   let x = (TwoFieldKlassBox(), TwoFieldKlassBox())
   async let y = transferToMainInt(x.0.k1) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -224,7 +239,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsTuple1() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsTuple2() async {
   let x = (TwoFieldKlassBox(), TwoFieldKlassBox())
   async let y = transferToMainInt(x.0.k1) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x.1) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -233,7 +249,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsTuple2() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsTuple3() async {
   let x = (TwoFieldKlassBox(), TwoFieldKlassBox())
   async let y = transferToMainInt(x.0.k1) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x.1.k2) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -242,7 +259,8 @@ func asyncLet_Let_ActorIsolated_AccessFieldsTuple3() async {
 func asyncLet_Let_ActorIsolated_AccessFieldsTuple4() async {
   let x = (TwoFieldKlassBox(), TwoFieldKlassBox())
   async let y = transferToMainInt(x.1.k1.field2) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x.0.k2.field) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -253,9 +271,11 @@ func asyncLet_Let_ActorIsolated_CallBuriedInOtherExpr1() async {
   let x2 = NonSendableKlass()
 
   async let y = useValue(transferToMainInt(x) + transferToMainInt(x2)) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-warning @-2 {{sending 'x2' risks causing data races}}
-  // expected-note @-3 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
+  // expected-warning @-3 {{sending 'x2' risks causing data races}}
+  // expected-ni-note @-4 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-5 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -267,9 +287,11 @@ func asyncLet_Let_ActorIsolated_CallBuriedInOtherExpr2() async {
   let x2 = NonSendableKlass()
 
   async let y = useValue(transferToMainInt(x) + transferToMainInt(x2)) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-warning @-2 {{sending 'x2' risks causing data races}}
-  // expected-note @-3 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
+  // expected-warning @-3 {{sending 'x2' risks causing data races}}
+  // expected-ni-note @-4 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-5 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x2) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -282,9 +304,11 @@ func asyncLet_Let_ActorIsolated_CallBuriedInOtherExpr3() async {
   let x2 = NonSendableKlass()
 
   async let y = useValue(transferToMainInt(x) + transferToMainInt(x2)) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-warning @-2 {{sending 'x2' risks causing data races}}
-  // expected-note @-3 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
+  // expected-warning @-3 {{sending 'x2' risks causing data races}}
+  // expected-ni-note @-4 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-5 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   // We only error on the first value captured if multiple values are captured
   // since we track a single partial_apply as a transfer instruction.
@@ -298,8 +322,9 @@ func asyncLet_Let_ActorIsolated_CallBuriedInOtherExpr4() async {
 
   async let y = useValue(transferToMainInt(x) + transferToMainInt(x))
   // expected-warning @-1:26 {{sending 'x' risks causing data races}}
-  // expected-note @-2:26 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-note @-3:49 {{access can happen concurrently}}
+  // expected-ni-note @-2:26 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-3:26 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
+  // expected-note @-4:49 {{access can happen concurrently}}
 
   let _ = await y
 }
@@ -311,8 +336,9 @@ func asyncLet_Let_ActorIsolated_CallBuriedInOtherExpr5() async {
 
   async let y = useValue(transferToMainInt(x) + transferToCustomInt(x))
   // expected-warning @-1 {{sending 'x' risks causing data races}}
-  // expected-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-note @-3:49 {{access can happen concurrently}}
+  // expected-ni-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-3 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
+  // expected-note @-4:49 {{access can happen concurrently}}
 
   let _ = await y
 }
@@ -323,8 +349,9 @@ func asyncLet_Let_ActorIsolated_MultipleAsyncLet1() async {
   let x = NonSendableKlass()
 
   async let y = useValue(transferToMainInt(x)), z = useValue(transferToMainInt(x)) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-note @-2:53 {{access can happen concurrently}}
+  // expected-ni-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
+  // expected-note @-3:53 {{access can happen concurrently}}
 
   let _ = await y
   let _ = await z
@@ -347,7 +374,8 @@ func asyncLet_Let_ActorIsolated_MultipleAsyncLet3() async {
 
   async let y = useValue(transferToMainInt(x)), z = useValue(transferToMainInt(x2))
   // expected-warning @-1 {{sending 'x2' risks causing data races}}
-  // expected-note @-2 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-2 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-3 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   useValue(x2) // expected-note {{access can happen concurrently}}
   let _ = await y
@@ -360,9 +388,11 @@ func asyncLet_Let_ActorIsolated_MultipleAsyncLet4() async {
 
   async let y = useValue(transferToMainInt(x)), z = useValue(transferToMainInt(x2))
   // expected-warning @-1 {{sending 'x' risks causing data races}}
-  // expected-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-warning @-3 {{sending 'x2' risks causing data races}}
-  // expected-note @-4 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-3 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
+  // expected-warning @-4 {{sending 'x2' risks causing data races}}
+  // expected-ni-note @-5 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-6 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   let _ = await y
   let _ = await z
@@ -376,9 +406,11 @@ func asyncLet_Let_ActorIsolated_MultipleAsyncLet5() async {
 
   async let y = useValue(transferToMainInt(x)), z = useValue(transferToMainInt(x2))
   // expected-warning @-1 {{sending 'x' risks causing data races}}
-  // expected-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-warning @-3 {{sending 'x2' risks causing data races}}
-  // expected-note @-4 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-3 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
+  // expected-warning @-4 {{sending 'x2' risks causing data races}}
+  // expected-ni-note @-5 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-6 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   let _ = await y
   useValue(x) // expected-note {{access can happen concurrently}}
@@ -392,9 +424,11 @@ func asyncLet_Let_ActorIsolated_MultipleAsyncLet6() async {
 
   async let y = useValue(transferToMainInt(x)), z = useValue(transferToMainInt(x2))
   // expected-warning @-1 {{sending 'x' risks causing data races}}
-  // expected-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-warning @-3 {{sending 'x2' risks causing data races}}
-  // expected-note @-4 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-3 {{sending 'x' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
+  // expected-warning @-4 {{sending 'x2' risks causing data races}}
+  // expected-ni-note @-5 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-6 {{sending 'x2' to main actor-isolated global function 'transferToMainInt' risks causing data races between main actor-isolated and local @concurrent uses}}
 
   let _ = await y
   useValue(x) // expected-note {{access can happen concurrently}}
@@ -722,7 +756,8 @@ func asyncLetWithoutCapture() async {
   //
   // NOTE: Error below will go away in next commit.
   async let x: NonSendableKlass = await returnValueFromMain()
-  // expected-warning @-1 {{non-Sendable 'NonSendableKlass'-typed result can not be returned from main actor-isolated global function 'returnValueFromMain()' to nonisolated context}}
+  // expected-ni-warning @-1 {{non-Sendable 'NonSendableKlass'-typed result can not be returned from main actor-isolated global function 'returnValueFromMain()' to nonisolated context}}
+  // expected-ni-ns-warning @-2 {{non-Sendable 'NonSendableKlass'-typed result can not be returned from main actor-isolated global function 'returnValueFromMain()' to @concurrent context}}
   let y = await x
   await transferToMain(y) // expected-warning {{sending 'y' risks causing data races}}
   // expected-note @-1 {{sending 'y' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
@@ -734,7 +769,8 @@ func asyncLet_Let_ActorIsolated_Method() async {
   let a = MyActor()
   let x = NonSendableKlass()
   async let y = a.useKlass(x) // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{sending 'x' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-ni-note @-1 {{sending 'x' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-ni-ns-note @-2 {{sending 'x' to actor-isolated instance method 'useKlass' risks causing data races between actor-isolated and local @concurrent uses}}
 
   useValue(x) // expected-note {{access can happen concurrently}}
   let _ = await y
diff --git a/test/Concurrency/transfernonsendable_cfg.sil b/test/Concurrency/transfernonsendable_cfg.sil
index 350d23c23917b..5204ba9643541 100644
--- a/test/Concurrency/transfernonsendable_cfg.sil
+++ b/test/Concurrency/transfernonsendable_cfg.sil
@@ -1,6 +1,4 @@
-// RUN: %target-sil-opt -send-non-sendable -enable-upcoming-feature RegionBasedIsolation -strict-concurrency=complete %s -verify
-
-// REQUIRES: swift_feature_RegionBasedIsolation
+// RUN: %target-sil-opt -send-non-sendable -strict-concurrency=complete %s -verify
 
 // PLEASE READ THIS!
 //
diff --git a/test/Concurrency/transfernonsendable_closureliterals_isolationinference.swift b/test/Concurrency/transfernonsendable_closureliterals_isolationinference.swift
index e073badfbf2ac..fb3669656dfd4 100644
--- a/test/Concurrency/transfernonsendable_closureliterals_isolationinference.swift
+++ b/test/Concurrency/transfernonsendable_closureliterals_isolationinference.swift
@@ -1,8 +1,11 @@
-// RUN: %target-swift-frontend -emit-sil -parse-as-library -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete %s -o - | %FileCheck %s
-// RUN: %target-swift-frontend -emit-sil -parse-as-library -target %target-swift-5.1-abi-triple -swift-version 6 -verify %s -o /dev/null
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete %s -o - 2>/dev/null | %FileCheck %s
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -target %target-swift-5.1-abi-triple -swift-version 6 -verify %s -o /dev/null -verify-additional-prefix ni-
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -target %target-swift-5.1-abi-triple -swift-version 5 -strict-concurrency=complete %s -o - -enable-upcoming-feature NonisolatedNonsendingByDefault 2>/dev/null | %FileCheck %s
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -target %target-swift-5.1-abi-triple -swift-version 6 -verify %s -o /dev/null -enable-upcoming-feature NonisolatedNonsendingByDefault -verify-additional-prefix ni-ns-
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // This test validates the behavior of transfernonsendable around
 // closure literals
@@ -24,10 +27,6 @@ func normalAcceptsClosure(_ x: () -> ()) {}
 func normalAcceptsSendingClosure(_ x: sending () -> ()) {}
 func normalAcceptsSendableClosure(_ x: @Sendable () -> ()) {}
 
-func inheritActorContextAcceptsClosure(@_inheritActorContext _ x: () -> ()) { }
-func inheritActorContextAcceptsSendingClosure(@_inheritActorContext _ x: sending () -> ()) { }
-func inheritActorContextAcceptsSendableClosure(@_inheritActorContext _ x: @Sendable () -> ()) { }
-
 @MainActor
 func normalGlobalActorAcceptsClosure(_ x: () -> ()) { }
 @MainActor
@@ -35,18 +34,10 @@ func normalGlobalActorAcceptsSendingClosure(_ x: sending () -> ()) { }
 @MainActor
 func normalGlobalActorAcceptsSendableClosure(_ x: @Sendable () -> ()) { }
 
-@MainActor
-func inheritActorContextGlobalActorAcceptsClosure(@_inheritActorContext _ x: () -> ()) { }
-@MainActor
-func inheritActorContextGlobalActorAcceptsSendingClosure(@_inheritActorContext _ x: sending () -> ()) { }
-@MainActor
-func inheritActorContextGlobalActorAcceptsSendableClosure(@_inheritActorContext _ x: @Sendable () -> ()) { }
-
 func normalAcceptsAsyncClosure(_ x: () async -> ()) {}
 func normalAcceptsSendingAsyncClosure(_ x: sending () async -> ()) {}
 func normalAcceptsSendableAsyncClosure(_ x: @Sendable () async -> ()) {}
 
-func inheritActorContextAcceptsAsyncClosure(@_inheritActorContext _ x: () async -> ()) { }
 func inheritActorContextAcceptsSendingAsyncClosure(@_inheritActorContext _ x: sending () async -> ()) { }
 func inheritActorContextAcceptsSendableAsyncClosure(@_inheritActorContext _ x: @Sendable () async -> ()) { }
 
@@ -57,8 +48,6 @@ func normalGlobalActorAcceptsSendingAsyncClosure(_ x: sending () async -> ()) {
 @MainActor
 func normalGlobalActorAcceptsSendableAsyncClosure(_ x: @Sendable () async -> ()) { }
 
-@MainActor
-func inheritActorContextGlobalActorAcceptsAsyncClosure(@_inheritActorContext _ x: () async -> ()) { }
 @MainActor
 func inheritActorContextGlobalActorAcceptsSendingAsyncClosure(@_inheritActorContext _ x: sending () async -> ()) { }
 @MainActor
@@ -68,10 +57,6 @@ func asyncNormalAcceptsClosure(_ x: () -> ()) async {}
 func asyncNormalAcceptsSendingClosure(_ x: sending () -> ()) async {}
 func asyncNormalAcceptsSendableClosure(_ x: @Sendable () -> ()) async {}
 
-func asyncInheritActorContextAcceptsClosure(@_inheritActorContext _ x: () -> ()) async {}
-func asyncInheritActorContextAcceptsSendingClosure(@_inheritActorContext _ x: sending () -> ()) async {}
-func asyncInheritActorContextAcceptsSendableClosure(@_inheritActorContext _ x: @Sendable () -> ()) async {}
-
 @MainActor
 func asyncNormalGlobalActorAcceptsClosure(_ x: () -> ()) async {}
 @MainActor
@@ -79,18 +64,10 @@ func asyncNormalGlobalActorAcceptsSendingClosure(_ x: sending () -> ()) async {}
 @MainActor
 func asyncNormalGlobalActorAcceptsSendableClosure(_ x: @Sendable () -> ()) async {}
 
-@MainActor
-func asyncInheritActorContextGlobalActorAcceptsClosure(@_inheritActorContext _ x: () -> ()) async {}
-@MainActor
-func asyncInheritActorContextGlobalActorAcceptsSendingClosure(@_inheritActorContext _ x: sending () -> ()) async {}
-@MainActor
-func asyncInheritActorContextGlobalActorAcceptsSendableClosure(@_inheritActorContext _ x: @Sendable () -> ()) async {}
-
 func asyncNormalAcceptsAsyncClosure(_ x: () async -> ()) async {}
 func asyncNormalAcceptsSendingAsyncClosure(_ x: sending () async -> ()) async {}
 func asyncNormalAcceptsSendableAsyncClosure(_ x: @Sendable () async -> ()) async {}
 
-func asyncInheritActorContextAcceptsAsyncClosure(@_inheritActorContext _ x: () async -> ()) async {}
 func asyncInheritActorContextAcceptsSendingAsyncClosure(@_inheritActorContext _ x: sending () async -> ()) async {}
 func asyncInheritActorContextAcceptsSendableAsyncClosure(@_inheritActorContext _ x: @Sendable () async -> ()) async {}
 
@@ -101,8 +78,6 @@ func asyncNormalGlobalActorAcceptsSendingAsyncClosure(_ x: sending () async -> (
 @MainActor
 func asyncNormalGlobalActorAcceptsSendableAsyncClosure(_ x: @Sendable () async -> ()) async {}
 
-@MainActor
-func asyncInheritActorContextGlobalActorAcceptsAsyncClosure(@_inheritActorContext _ x: () async -> ()) async {}
 @MainActor
 func asyncInheritActorContextGlobalActorAcceptsSendingAsyncClosure(@_inheritActorContext _ x: sending () async -> ()) async {}
 @MainActor
@@ -138,26 +113,6 @@ func test_CallerSyncNormal_CalleeSyncNonIsolated() async {
     normalAcceptsSendableClosure { }
 }
 
-@CustomActor
-func test_CallerSyncInheritsActorContext_CalleeSyncNonisolated() {
-    // CHECK: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference042test_CallerSyncInheritsActorContext_CalleeF11NonisolatedyyF'
-
-    // CHECK-LABEL: // closure #1 in test_CallerSyncInheritsActorContext_CalleeSyncNonisolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    inheritActorContextAcceptsClosure { }
-
-    // This is a synchronous closure, so we error here.
-    //
-    // CHECK-LABEL: // closure #2 in test_CallerSyncInheritsActorContext_CalleeSyncNonisolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    inheritActorContextAcceptsSendingClosure { } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-    //  expected-note @-1 {{Passing global actor 'CustomActor'-isolated value of non-Sendable type '() -> ()' as a 'sending' parameter to global function 'inheritActorContextAcceptsSendingClosure' risks causing races inbetween global actor 'CustomActor'-isolated uses and uses reachable from 'inheritActorContextAcceptsSendingClosure'}}
-
-    // CHECK-LABEL: // closure #3 in test_CallerSyncInheritsActorContext_CalleeSyncNonisolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    inheritActorContextAcceptsSendableClosure { }
-}
-
 @CustomActor
 func test_CallerSyncNormal_CalleeSyncMainActorIsolated() async {
     // CHECK-LABEL: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference028test_CallerSyncNormal_CalleeF17MainActorIsolatedyyYaF'
@@ -176,27 +131,6 @@ func test_CallerSyncNormal_CalleeSyncMainActorIsolated() async {
     await normalGlobalActorAcceptsSendableClosure { }
 }
 
-@CustomActor
-func test_CallerSyncInheritsActorContext_CalleeSyncMainActorIsolated() async {
-    // CHECK-LABEL: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference042test_CallerSyncInheritsActorContext_Calleef4MainH8IsolatedyyYaF'
-
-    // CHECK-LABEL: // closure #1 in test_CallerSyncInheritsActorContext_CalleeSyncMainActorIsolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await inheritActorContextGlobalActorAcceptsClosure { } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-    // expected-note @-1 {{sending global actor 'CustomActor'-isolated value of non-Sendable type '() -> ()' to main actor-isolated global function 'inheritActorContextGlobalActorAcceptsClosure' risks causing races in between global actor 'CustomActor'-isolated and main actor-isolated uses}}
-
-    // This is a synchronous closure, so we error here.
-    //
-    // CHECK-LABEL: // closure #2 in test_CallerSyncInheritsActorContext_CalleeSyncMainActorIsolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await inheritActorContextGlobalActorAcceptsSendingClosure { } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-    // expected-note @-1 {{Passing global actor 'CustomActor'-isolated value of non-Sendable type '() -> ()' as a 'sending' parameter to global function 'inheritActorContextGlobalActorAcceptsSendingClosure' risks causing races inbetween global actor 'CustomActor'-isolated uses and uses reachable from 'inheritActorContextGlobalActorAcceptsSendingClosure'}}
-
-    // CHECK-LABEL: // closure #3 in test_CallerSyncInheritsActorContext_CalleeSyncMainActorIsolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await inheritActorContextGlobalActorAcceptsSendableClosure { }
-}
-
 ////////////////////////////////////////////////
 // MARK: Global Actor Sync User Async Closure //
 ////////////////////////////////////////////////
@@ -223,13 +157,9 @@ func test_CallerSyncInheritsActorContext_CalleeAsyncNonisolated() {
 
     // CHECK-LABEL: // closure #1 in test_CallerSyncInheritsActorContext_CalleeAsyncNonisolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    inheritActorContextAcceptsAsyncClosure { }
-
-    // CHECK-LABEL: // closure #2 in test_CallerSyncInheritsActorContext_CalleeAsyncNonisolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     inheritActorContextAcceptsSendingAsyncClosure { }
 
-    // CHECK-LABEL: // closure #3 in test_CallerSyncInheritsActorContext_CalleeAsyncNonisolated()
+    // CHECK-LABEL: // closure #2 in test_CallerSyncInheritsActorContext_CalleeAsyncNonisolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     inheritActorContextAcceptsSendableAsyncClosure { }
 }
@@ -258,13 +188,9 @@ func test_CallerSyncInheritsActorContext_CalleeAsyncMainActorIsolated() async {
 
     // CHECK-LABEL: // closure #1 in test_CallerSyncInheritsActorContext_CalleeAsyncMainActorIsolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await inheritActorContextGlobalActorAcceptsAsyncClosure { }
-
-    // CHECK-LABEL: // closure #2 in test_CallerSyncInheritsActorContext_CalleeAsyncMainActorIsolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     await inheritActorContextGlobalActorAcceptsSendingAsyncClosure { }
 
-    // CHECK-LABEL: // closure #3 in test_CallerSyncInheritsActorContext_CalleeAsyncMainActorIsolated()
+    // CHECK-LABEL: // closure #2 in test_CallerSyncInheritsActorContext_CalleeAsyncMainActorIsolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     await inheritActorContextGlobalActorAcceptsSendableAsyncClosure { }
 }
@@ -281,8 +207,8 @@ func test_CallerAsyncNormal_CalleeSyncNonIsolated() async {
 
     // CHECK-LABEL: closure #1 in test_CallerAsyncNormal_CalleeSyncNonIsolated()
     // CHECK-NEXT: Isolation: global_actor. type: CustomActor
-    await asyncNormalAcceptsClosure { } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-    // expected-note @-1 {{sending global actor 'CustomActor'-isolated value of non-Sendable type '() -> ()' to nonisolated global function 'asyncNormalAcceptsClosure' risks causing races in between global actor 'CustomActor'-isolated and nonisolated uses}}
+    await asyncNormalAcceptsClosure { } // expected-ni-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+    // expected-ni-note @-1 {{sending global actor 'CustomActor'-isolated value of non-Sendable type '() -> ()' to nonisolated global function 'asyncNormalAcceptsClosure' risks causing races in between global actor 'CustomActor'-isolated and nonisolated uses}}
 
     // CHECK-LABEL: closure #2 in test_CallerAsyncNormal_CalleeSyncNonIsolated()
     // CHECK-NEXT: Isolation: nonisolated
@@ -293,27 +219,6 @@ func test_CallerAsyncNormal_CalleeSyncNonIsolated() async {
     await asyncNormalAcceptsSendableClosure { }
 }
 
-@CustomActor
-func test_CallerAsyncInheritsActorContext_CalleeSyncNonisolated() async {
-    // CHECK: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference58test_CallerAsyncInheritsActorContext_CalleeSyncNonisolatedyyYaF'
-
-    // CHECK-LABEL: // closure #1 in test_CallerAsyncInheritsActorContext_CalleeSyncNonisolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await asyncInheritActorContextAcceptsClosure { } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-    // expected-note @-1 {{sending global actor 'CustomActor'-isolated value of non-Sendable type '() -> ()' to nonisolated global function 'asyncInheritActorContextAcceptsClosure' risks causing races in between global actor 'CustomActor'-isolated and nonisolated uses}}
-
-    // This is a synchronous closure, so we error here.
-    //
-    // CHECK-LABEL: // closure #2 in test_CallerAsyncInheritsActorContext_CalleeSyncNonisolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await asyncInheritActorContextAcceptsSendingClosure { } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-    // expected-note @-1 {{Passing global actor 'CustomActor'-isolated value of non-Sendable type '() -> ()' as a 'sending' parameter to global function 'asyncInheritActorContextAcceptsSendingClosure' risks causing races inbetween global actor 'CustomActor'-isolated uses and uses reachable from 'asyncInheritActorContextAcceptsSendingClosure'}}
-
-    // CHECK-LABEL: // closure #3 in test_CallerAsyncInheritsActorContext_CalleeSyncNonisolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await asyncInheritActorContextAcceptsSendableClosure { }
-}
-
 @CustomActor
 func test_CallerAsyncNormal_CalleeSyncMainActorIsolated() async {
     // CHECK-LABEL: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference50test_CallerAsyncNormal_CalleeSyncMainActorIsolatedyyYaF'
@@ -332,27 +237,6 @@ func test_CallerAsyncNormal_CalleeSyncMainActorIsolated() async {
     await asyncNormalGlobalActorAcceptsSendableClosure { }
 }
 
-@CustomActor
-func test_CallerAsyncInheritsActorContext_CalleeSyncMainActorIsolated() async {
-    // CHECK-LABEL: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference051test_CallerAsyncInheritsActorContext_CalleeSyncMainH8IsolatedyyYaF'
-
-    // CHECK-LABEL: // closure #1 in test_CallerAsyncInheritsActorContext_CalleeSyncMainActorIsolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await asyncInheritActorContextGlobalActorAcceptsClosure { } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-    // expected-note @-1 {{sending global actor 'CustomActor'-isolated value of non-Sendable type '() -> ()' to main actor-isolated global function 'asyncInheritActorContextGlobalActorAcceptsClosure' risks causing races in between global actor 'CustomActor'-isolated and main actor-isolated uses}}
-
-    // This is a synchronous closure, so we error here.
-    //
-    // CHECK-LABEL: // closure #2 in test_CallerAsyncInheritsActorContext_CalleeSyncMainActorIsolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await asyncInheritActorContextGlobalActorAcceptsSendingClosure { } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-    // expected-note @-1 {{Passing global actor 'CustomActor'-isolated value of non-Sendable type '() -> ()' as a 'sending' parameter to global function 'asyncInheritActorContextGlobalActorAcceptsSendingClosure' risks causing races inbetween global actor 'CustomActor'-isolated uses and uses reachable from 'asyncInheritActorContextGlobalActorAcceptsSendingClosure'}}
-
-    // CHECK-LABEL: // closure #3 in test_CallerAsyncInheritsActorContext_CalleeSyncMainActorIsolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await asyncInheritActorContextGlobalActorAcceptsSendableClosure { }
-}
-
 /////////////////////////////////////////////////
 // MARK: Global Actor Async User Async Closure //
 /////////////////////////////////////////////////
@@ -363,8 +247,8 @@ func test_CallerAsyncNormal_CalleeAsyncNonIsolated() async {
 
     // CHECK-LABEL: closure #1 in test_CallerAsyncNormal_CalleeAsyncNonIsolated()
     // CHECK-NEXT: Isolation: global_actor. type: CustomActor
-    await asyncNormalAcceptsAsyncClosure { } // expected-error {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
-    // expected-note @-1 {{sending global actor 'CustomActor'-isolated value of non-Sendable type '() async -> ()' to nonisolated global function 'asyncNormalAcceptsAsyncClosure' risks causing races in between global actor 'CustomActor'-isolated and nonisolated uses}}
+    await asyncNormalAcceptsAsyncClosure { } // expected-ni-error {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
+    // expected-ni-note @-1 {{sending global actor 'CustomActor'-isolated value of non-Sendable type '() async -> ()' to nonisolated global function 'asyncNormalAcceptsAsyncClosure' risks causing races in between global actor 'CustomActor'-isolated and nonisolated uses}}
 
     // CHECK-LABEL: closure #2 in test_CallerAsyncNormal_CalleeAsyncNonIsolated()
     // CHECK-NEXT: Isolation: nonisolated
@@ -381,21 +265,17 @@ func test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated() async {
 
     // CHECK-LABEL: // closure #1 in test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await asyncInheritActorContextAcceptsAsyncClosure { }
-
-    // CHECK-LABEL: // closure #2 in test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     await asyncInheritActorContextAcceptsSendingAsyncClosure { }
 
-    // CHECK-LABEL: // closure #3 in test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
+    // CHECK-LABEL: // closure #2 in test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     await asyncInheritActorContextAcceptsSendingAsyncClosure { @CustomActor in }
 
-    // CHECK-LABEL: // closure #4 in test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
+    // CHECK-LABEL: // closure #3 in test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
     // CHECK-NEXT: // Isolation: global_actor. type: MainActor
     await asyncInheritActorContextAcceptsSendingAsyncClosure { @MainActor in }
 
-    // CHECK-LABEL: // closure #5 in test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
+    // CHECK-LABEL: // closure #4 in test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     await asyncInheritActorContextAcceptsSendableAsyncClosure { }
 }
@@ -424,21 +304,17 @@ func test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated() async {
 
     // CHECK-LABEL: // closure #1 in test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
-    await asyncInheritActorContextGlobalActorAcceptsAsyncClosure { }
-
-    // CHECK-LABEL: // closure #2 in test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
-    // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     await asyncInheritActorContextGlobalActorAcceptsSendingAsyncClosure { }
 
-    // CHECK-LABEL: // closure #3 in test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
+    // CHECK-LABEL: // closure #2 in test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     await asyncInheritActorContextGlobalActorAcceptsSendingAsyncClosure { @CustomActor in }
 
-    // CHECK-LABEL: // closure #4 in test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
+    // CHECK-LABEL: // closure #3 in test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
     // CHECK-NEXT: // Isolation: global_actor. type: MainActor
     await asyncInheritActorContextGlobalActorAcceptsSendingAsyncClosure { @MainActor in }
 
-    // CHECK-LABEL: // closure #5 in test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
+    // CHECK-LABEL: // closure #4 in test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
     // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
     await asyncInheritActorContextGlobalActorAcceptsSendableAsyncClosure { }
 }
@@ -464,26 +340,6 @@ extension MyActor {
         normalAcceptsSendableClosure { print(self) }
     }
 
-    func test_CallerSyncInheritsActorContext_CalleeSyncNonisolated() {
-        // CHECK: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference7MyActorC023test_CallerSyncInheritse14Context_CalleeH11NonisolatedyyF'
-
-        // CHECK-LABEL: // closure #1 in MyActor.test_CallerSyncInheritsActorContext_CalleeSyncNonisolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        inheritActorContextAcceptsClosure { print(self) }
-
-        // This is a synchronous closure, so we error here.
-        //
-        // CHECK-LABEL: // closure #2 in MyActor.test_CallerSyncInheritsActorContext_CalleeSyncNonisolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        inheritActorContextAcceptsSendingClosure { // expected-error {{passing closure as a 'sending' parameter risks causing data races between 'self'-isolated code and concurrent execution of the closure}}
-            print(self) // expected-note {{closure captures 'self'}}
-        }
-
-        // CHECK-LABEL: // closure #3 in MyActor.test_CallerSyncInheritsActorContext_CalleeSyncNonisolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        inheritActorContextAcceptsSendableClosure { print(self) }
-    }
-
     func test_CallerSyncNormal_CalleeSyncMainActorIsolated() async {
         // CHECK-LABEL: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference7MyActorC028test_CallerSyncNormal_Calleeh4MainE8IsolatedyyYaF'
 
@@ -500,27 +356,6 @@ extension MyActor {
         // CHECK-NEXT: // Isolation: nonisolated
         await normalGlobalActorAcceptsSendableClosure { print(self) }
     }
-
-    func test_CallerSyncInheritsActorContext_CalleeSyncMainActorIsolated() async {
-        // CHECK-LABEL: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference7MyActorC023test_CallerSyncInheritse14Context_Calleeh4MainE8IsolatedyyYaF'
-
-        // CHECK-LABEL: // closure #1 in MyActor.test_CallerSyncInheritsActorContext_CalleeSyncMainActorIsolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await inheritActorContextGlobalActorAcceptsClosure { print(self) } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-        // expected-note @-1 {{sending 'self'-isolated value of non-Sendable type '() -> ()' to main actor-isolated global function 'inheritActorContextGlobalActorAcceptsClosure' risks causing races in between 'self'-isolated and main actor-isolated uses}}
-
-        // This is a synchronous closure, so we error here.
-        //
-        // CHECK-LABEL: // closure #2 in MyActor.test_CallerSyncInheritsActorContext_CalleeSyncMainActorIsolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await inheritActorContextGlobalActorAcceptsSendingClosure { // expected-error {{passing closure as a 'sending' parameter risks causing data races between 'self'-isolated code and concurrent execution of the closure}}
-            print(self) // expected-note {{closure captures 'self'}}
-        }
-
-        // CHECK-LABEL: // closure #3 in MyActor.test_CallerSyncInheritsActorContext_CalleeSyncMainActorIsolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await inheritActorContextGlobalActorAcceptsSendableClosure { print(self) }
-    }
 }
 
 //////////////////////////////////////////////////
@@ -550,13 +385,9 @@ extension MyActor {
 
         // CHECK-LABEL: // closure #1 in MyActor.test_CallerSyncInheritsActorContext_CalleeAsyncNonisolated()
         // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        inheritActorContextAcceptsAsyncClosure { print(self) }
-
-        // CHECK-LABEL: // closure #2 in MyActor.test_CallerSyncInheritsActorContext_CalleeAsyncNonisolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
         inheritActorContextAcceptsSendingAsyncClosure { print(self) }
 
-        // CHECK-LABEL: // closure #3 in MyActor.test_CallerSyncInheritsActorContext_CalleeAsyncNonisolated()
+        // CHECK-LABEL: // closure #2 in MyActor.test_CallerSyncInheritsActorContext_CalleeAsyncNonisolated()
         // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
         inheritActorContextAcceptsSendableAsyncClosure { print(self) }
     }
@@ -583,13 +414,9 @@ extension MyActor {
 
         // CHECK-LABEL: // closure #1 in MyActor.test_CallerSyncInheritsActorContext_CalleeAsyncMainActorIsolated()
         // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await inheritActorContextGlobalActorAcceptsAsyncClosure { print(self) }
-
-        // CHECK-LABEL: // closure #2 in MyActor.test_CallerSyncInheritsActorContext_CalleeAsyncMainActorIsolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
         await inheritActorContextGlobalActorAcceptsSendingAsyncClosure { print(self) }
 
-        // CHECK-LABEL: // closure #3 in MyActor.test_CallerSyncInheritsActorContext_CalleeAsyncMainActorIsolated()
+        // CHECK-LABEL: // closure #2 in MyActor.test_CallerSyncInheritsActorContext_CalleeAsyncMainActorIsolated()
         // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
         await inheritActorContextGlobalActorAcceptsSendableAsyncClosure { print(self) }
     }
@@ -608,8 +435,8 @@ extension MyActor {
 
         // CHECK-LABEL: closure #1 in MyActor.test_CallerAsyncNormal_CalleeSyncNonIsolated()
         // CHECK-NEXT: Isolation: actor_instance. name: 'self'
-        await asyncNormalAcceptsClosure { print(self) } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-        // expected-note @-1 {{sending 'self'-isolated value of non-Sendable type '() -> ()' to nonisolated global function 'asyncNormalAcceptsClosure' risks causing races in between 'self'-isolated and nonisolated uses}}
+        await asyncNormalAcceptsClosure { print(self) } // expected-ni-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+        // expected-ni-note @-1 {{sending 'self'-isolated value of non-Sendable type '() -> ()' to nonisolated global function 'asyncNormalAcceptsClosure' risks causing races in between 'self'-isolated and nonisolated uses}}
 
         // CHECK-LABEL: closure #2 in MyActor.test_CallerAsyncNormal_CalleeSyncNonIsolated()
         // CHECK-NEXT: Isolation: nonisolated
@@ -620,27 +447,6 @@ extension MyActor {
         await asyncNormalAcceptsSendableClosure { print(self) }
     }
 
-    func test_CallerAsyncInheritsActorContext_CalleeSyncNonisolated() async {
-        // CHECK: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference7MyActorC024test_CallerAsyncInheritsE29Context_CalleeSyncNonisolatedyyYaF'
-
-        // CHECK-LABEL: // closure #1 in MyActor.test_CallerAsyncInheritsActorContext_CalleeSyncNonisolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await asyncInheritActorContextAcceptsClosure { print(self) } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-        // expected-note @-1 {{sending 'self'-isolated value of non-Sendable type '() -> ()' to nonisolated global function 'asyncInheritActorContextAcceptsClosure' risks causing races in between 'self'-isolated and nonisolated uses}}
-
-        // This is a synchronous closure, so we error here.
-        //
-        // CHECK-LABEL: // closure #2 in MyActor.test_CallerAsyncInheritsActorContext_CalleeSyncNonisolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await asyncInheritActorContextAcceptsSendingClosure { // expected-error {{passing closure as a 'sending' parameter risks causing data races between 'self'-isolated code and concurrent execution of the closure}}
-            print(self) // expected-note {{closure captures 'self'}}
-        }
-
-        // CHECK-LABEL: // closure #3 in MyActor.test_CallerAsyncInheritsActorContext_CalleeSyncNonisolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await asyncInheritActorContextAcceptsSendableClosure { print(self) }
-    }
-
     func test_CallerAsyncNormal_CalleeSyncMainActorIsolated() async {
         // CHECK-LABEL: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference7MyActorC037test_CallerAsyncNormal_CalleeSyncMainE8IsolatedyyYaF'
 
@@ -657,27 +463,6 @@ extension MyActor {
         // CHECK-NEXT: // Isolation: nonisolated
         await asyncNormalGlobalActorAcceptsSendableClosure { print(self) }
     }
-
-    func test_CallerAsyncInheritsActorContext_CalleeSyncMainActorIsolated() async {
-        // CHECK-LABEL: } // end sil function '$s54transfernonsendable_closureliterals_isolationinference7MyActorC024test_CallerAsyncInheritse22Context_CalleeSyncMainE8IsolatedyyYaF'
-
-        // CHECK-LABEL: // closure #1 in MyActor.test_CallerAsyncInheritsActorContext_CalleeSyncMainActorIsolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await asyncInheritActorContextGlobalActorAcceptsClosure { print(self) } // expected-error {{sending value of non-Sendable type '() -> ()' risks causing data races}}
-        // expected-note @-1 {{sending 'self'-isolated value of non-Sendable type '() -> ()' to main actor-isolated global function 'asyncInheritActorContextGlobalActorAcceptsClosure' risks causing races in between 'self'-isolated and main actor-isolated uses}}
-
-        // This is a synchronous function, so we error.
-        //
-        // CHECK-LABEL: // closure #2 in MyActor.test_CallerAsyncInheritsActorContext_CalleeSyncMainActorIsolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await asyncInheritActorContextGlobalActorAcceptsSendingClosure { // expected-error {{passing closure as a 'sending' parameter risks causing data races between 'self'-isolated code and concurrent execution of the closure}}
-            print(self) // expected-note {{closure captures 'self'}}
-        }
-
-        // CHECK-LABEL: // closure #3 in MyActor.test_CallerAsyncInheritsActorContext_CalleeSyncMainActorIsolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await asyncInheritActorContextGlobalActorAcceptsSendableClosure { print(self) }
-    }
 }
 
 ///////////////////////////////////////////////////
@@ -691,8 +476,8 @@ extension MyActor {
 
         // CHECK-LABEL: closure #1 in MyActor.test_CallerAsyncNormal_CalleeAsyncNonIsolated()
         // CHECK-NEXT: Isolation: actor_instance. name: 'self'
-        await asyncNormalAcceptsAsyncClosure { print(self) } // expected-error {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
-        // expected-note @-1 {{sending 'self'-isolated value of non-Sendable type '() async -> ()' to nonisolated global function 'asyncNormalAcceptsAsyncClosure' risks causing races in between 'self'-isolated and nonisolated uses}}
+        await asyncNormalAcceptsAsyncClosure { print(self) } // expected-ni-error {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
+        // expected-ni-note @-1 {{sending 'self'-isolated value of non-Sendable type '() async -> ()' to nonisolated global function 'asyncNormalAcceptsAsyncClosure' risks causing races in between 'self'-isolated and nonisolated uses}}
 
         // CHECK-LABEL: closure #2 in MyActor.test_CallerAsyncNormal_CalleeAsyncNonIsolated()
         // CHECK-NEXT: Isolation: nonisolated
@@ -708,21 +493,17 @@ extension MyActor {
 
         // CHECK-LABEL: // closure #1 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
         // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await asyncInheritActorContextAcceptsAsyncClosure { print(self) }
-
-        // CHECK-LABEL: // closure #2 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
         await asyncInheritActorContextAcceptsSendingAsyncClosure { print(self) }
 
-        // CHECK-LABEL: // closure #3 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
+        // CHECK-LABEL: // closure #2 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
         // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
         await asyncInheritActorContextAcceptsSendingAsyncClosure { @CustomActor in print(self) }
 
-        // CHECK-LABEL: // closure #4 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
+        // CHECK-LABEL: // closure #3 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
         // CHECK-NEXT: // Isolation: global_actor. type: MainActor
         await asyncInheritActorContextAcceptsSendingAsyncClosure { @MainActor in print(self) }
 
-        // CHECK-LABEL: // closure #5 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
+        // CHECK-LABEL: // closure #4 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncNonisolated()
         // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
         await asyncInheritActorContextAcceptsSendableAsyncClosure { print(self) }
     }
@@ -749,21 +530,17 @@ extension MyActor {
 
         // CHECK-LABEL: // closure #1 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
         // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
-        await asyncInheritActorContextGlobalActorAcceptsAsyncClosure { print(self) }
-
-        // CHECK-LABEL: // closure #2 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
-        // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
         await asyncInheritActorContextGlobalActorAcceptsSendingAsyncClosure { print(self) }
 
-        // CHECK-LABEL: // closure #3 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
+        // CHECK-LABEL: // closure #2 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
         // CHECK-NEXT: // Isolation: global_actor. type: CustomActor
         await asyncInheritActorContextGlobalActorAcceptsSendingAsyncClosure { @CustomActor in print(self) }
 
-        // CHECK-LABEL: // closure #4 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
+        // CHECK-LABEL: // closure #3 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
         // CHECK-NEXT: // Isolation: global_actor. type: MainActor
         await asyncInheritActorContextGlobalActorAcceptsSendingAsyncClosure { @MainActor in print(self) }
 
-        // CHECK-LABEL: // closure #5 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
+        // CHECK-LABEL: // closure #4 in MyActor.test_CallerAsyncInheritsActorContext_CalleeAsyncMainActorIsolated()
         // CHECK-NEXT: // Isolation: actor_instance. name: 'self'
         await asyncInheritActorContextGlobalActorAcceptsSendableAsyncClosure { print(self) }
     }
diff --git a/test/Concurrency/transfernonsendable_defer_and_typecheck_only.swift b/test/Concurrency/transfernonsendable_defer_and_typecheck_only.swift
index c6e2e372f1c5b..9d86bdd81ca62 100644
--- a/test/Concurrency/transfernonsendable_defer_and_typecheck_only.swift
+++ b/test/Concurrency/transfernonsendable_defer_and_typecheck_only.swift
@@ -5,7 +5,7 @@
 
 /*
  This file tests the experimental TransferNonSendable feature. This feature causes the passing
- of non-sendable values to isolation-crossing calls to not yield diagnostics during AST passes,
+ of non-Sendable values to isolation-crossing calls to not yield diagnostics during AST passes,
  but to instead emit them later during a mandatory SIL pass. This file in particular checks that
  isolation crossing via argument passing is deferred, but that isolation crossing via returned
  results is not deferred. This is done because flow-sensitive "region" checking
@@ -46,7 +46,7 @@ actor A {
         // Non-sendable value passed from nonisolated to actor isolated
 
         await takesNS(ns)
-        //deferred-warning@-1{{passing argument of non-sendable type 'NonSendable' outside of actor-isolated context may introduce data races}}
+        //deferred-warning@-1{{passing argument of non-Sendable type 'NonSendable' outside of actor-isolated context may introduce data races}}
 
         _ = await retsNS()
     }
@@ -55,7 +55,7 @@ actor A {
         // Non-sendable value passed between the isolation of two different actors
 
         await a.actorTakesNS(ns)
-        //deferred-warning@-1{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+        //deferred-warning@-1{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
         _ = await a.actorRetsNS()
     }
diff --git a/test/Concurrency/transfernonsendable_functionsubtyping.swift b/test/Concurrency/transfernonsendable_functionsubtyping.swift
index de7b2fc8bb893..22739fcc20053 100644
--- a/test/Concurrency/transfernonsendable_functionsubtyping.swift
+++ b/test/Concurrency/transfernonsendable_functionsubtyping.swift
@@ -1,4 +1,5 @@
 // RUN: %target-typecheck-verify-swift -swift-version 6
+// RUN: %target-typecheck-verify-swift -swift-version 6 -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // READ THIS! This file only contains tests that validate that the relevant
 // function subtyping rules for sending work. Please do not put other tests in
@@ -6,6 +7,7 @@
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
diff --git a/test/Concurrency/transfernonsendable_global_actor.swift b/test/Concurrency/transfernonsendable_global_actor.swift
index 1b3b7a3074a0f..157fd2af74d76 100644
--- a/test/Concurrency/transfernonsendable_global_actor.swift
+++ b/test/Concurrency/transfernonsendable_global_actor.swift
@@ -1,13 +1,15 @@
-// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify -verify-additional-prefix tns-  %s -o /dev/null -parse-as-library -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify -verify-additional-prefix ni- %s -o /dev/null -parse-as-library -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify -verify-additional-prefix ni-ns- %s -o /dev/null -parse-as-library -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
 ////////////////////////
 
-class NonSendableKlass {} // expected-complete-note {{}}
+class NonSendableKlass {}
 final class SendableKlass : Sendable {}
 
 actor CustomActorInstance {}
@@ -58,13 +60,13 @@ extension NonSendableGlobalActorIsolatedEnum: Sendable {}
 // MARK: Tests //
 /////////////////
 
-private class NonSendableLinkedList<T> { // expected-complete-note 5{{}}
+private class NonSendableLinkedList<T> {
   var listHead: NonSendableLinkedListNode<T>?
 
   init() { listHead = nil }
 }
 
-private class NonSendableLinkedListNode<T> { // expected-complete-note 3{{}}
+private class NonSendableLinkedListNode<T> {
   var next: NonSendableLinkedListNode?
   var data: T?
 
@@ -77,15 +79,15 @@ private class NonSendableLinkedListNode<T> { // expected-complete-note 3{{}}
 @CustomActor func useCustomActor1() async {
   let x = firstList
 
-  await transferToMainActor(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-  // expected-tns-note @-1 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainActor' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableLinkedList<Int>' into main actor-isolated context may introduce data races}}
+  await transferToMainActor(x) // expected-warning {{sending 'x' risks causing data races}}
+  // expected-note @-1 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainActor' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+ 
 
   let y = secondList.listHead!.next!
 
-  await transferToMainActor(y) // expected-tns-warning {{sending 'y' risks causing data races}}
-  // expected-tns-note @-1 {{sending global actor 'CustomActor'-isolated 'y' to main actor-isolated global function 'transferToMainActor' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableLinkedListNode<Int>' into main actor-isolated context may introduce data races}}
+  await transferToMainActor(y) // expected-warning {{sending 'y' risks causing data races}}
+  // expected-note @-1 {{sending global actor 'CustomActor'-isolated 'y' to main actor-isolated global function 'transferToMainActor' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+ 
 }
 
 @CustomActor func useCustomActor2() async {
@@ -95,9 +97,9 @@ private class NonSendableLinkedListNode<T> { // expected-complete-note 3{{}}
     x = secondList.listHead!.next!
   }
 
-  await transferToMainActor(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-  // expected-tns-note @-1 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainActor' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendableLinkedListNode<Int>' into main actor-isolated context may introduce data races}}
+  await transferToMainActor(x) // expected-warning {{sending 'x' risks causing data races}}
+  // expected-note @-1 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainActor' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+ 
 }
 
 @CustomActor func useCustomActor3() async {
@@ -124,12 +126,12 @@ private class NonSendableLinkedListNode<T> { // expected-complete-note 3{{}}
   // This is ok since the nonisolated function cannot transfer x, so once we
   // return x will be isolated again.
   await transferToNonIsolated(x)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableLinkedListNode<Int>' outside of global actor 'CustomActor'-isolated context may introduce data races}}
+ 
 
   useValue(x)
 }
 
-private struct StructContainingValue { // expected-complete-note 2{{}}
+private struct StructContainingValue {
   var x = NonSendableLinkedList<Int>()
   var y = SendableKlass()
 }
@@ -141,7 +143,7 @@ private struct StructContainingValue { // expected-complete-note 2{{}}
   // This is ok since the nonisolated function cannot transfer x meaning after
   // we return we know that x will be disconnected upon return as well.
   await transferToNonIsolated(x)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'StructContainingValue' outside of global actor 'CustomActor'-isolated context may introduce data races}}
+ 
 
   useValue(x)
 }
@@ -150,9 +152,9 @@ private struct StructContainingValue { // expected-complete-note 2{{}}
   var x = StructContainingValue()
   x.x = firstList
 
-  await transferToNonIsolated(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-  // expected-tns-note @-1 {{sending global actor 'CustomActor'-isolated 'x' to nonisolated global function 'transferToNonIsolated' risks causing data races between nonisolated and global actor 'CustomActor'-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'StructContainingValue' outside of global actor 'CustomActor'-isolated context may introduce data races}}
+  await transferToNonIsolated(x) // expected-ni-warning {{sending 'x' risks causing data races}}
+  // expected-ni-note @-1 {{sending global actor 'CustomActor'-isolated 'x' to nonisolated global function 'transferToNonIsolated' risks causing data races between nonisolated and global actor 'CustomActor'-isolated uses}}
+ 
 
   useValue(x)
 }
@@ -163,8 +165,8 @@ private struct StructContainingValue { // expected-complete-note 2{{}}
 
   // This is safe since the nonisolated function cannot transfer x further.
   await transferToNonIsolated(x)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '(NonSendableLinkedList<Int>, NonSendableLinkedList<Int>)' outside of global actor 'CustomActor'-isolated context may introduce data races}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '(NonSendableLinkedList<Int>, NonSendableLinkedList<Int>)' outside of global actor 'CustomActor'-isolated context may introduce data races}}
+ 
+ 
 
   useValue(x)
 }
@@ -174,10 +176,10 @@ private struct StructContainingValue { // expected-complete-note 2{{}}
 
   x.1 = firstList
 
-  await transferToNonIsolated(x) // expected-tns-warning {{sending 'x' risks causing data races}}
-  // expected-tns-note @-1 {{sending global actor 'CustomActor'-isolated 'x' to nonisolated global function 'transferToNonIsolated' risks causing data races between nonisolated and global actor 'CustomActor'-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '(NonSendableLinkedList<Int>, NonSendableLinkedList<Int>)' outside of global actor 'CustomActor'-isolated context may introduce data races}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type '(NonSendableLinkedList<Int>, NonSendableLinkedList<Int>)' outside of global actor 'CustomActor'-isolated context may introduce data races}}
+  await transferToNonIsolated(x) // expected-ni-warning {{sending 'x' risks causing data races}}
+  // expected-ni-note @-1 {{sending global actor 'CustomActor'-isolated 'x' to nonisolated global function 'transferToNonIsolated' risks causing data races between nonisolated and global actor 'CustomActor'-isolated uses}}
+ 
+ 
 
   useValue(x)
 }
@@ -195,8 +197,8 @@ struct Clock {
 // We used to crash when inferring the type for the diagnostic below.
 @MainActor func testIndirectParametersHandledCorrectly() async {
   let c = Clock()
-  let _: Int = await c.measure { // expected-tns-warning {{sending value of non-Sendable type '() async -> Int' risks causing data races}}
-    // expected-tns-note @-1 {{sending main actor-isolated value of non-Sendable type '() async -> Int' to nonisolated instance method 'measure' risks causing races in between main actor-isolated and nonisolated uses}}
+  let _: Int = await c.measure { // expected-ni-warning {{sending value of non-Sendable type '() async -> Int' risks causing data races}}
+    // expected-ni-note @-1 {{sending main actor-isolated value of non-Sendable type '() async -> Int' to nonisolated instance method 'measure' risks causing races in between main actor-isolated and nonisolated uses}}
     try! await c.sleep()
   }
 }
@@ -205,11 +207,9 @@ struct Clock {
   let ns = customActorIsolatedGlobal
 
   let _ = { @MainActor in
-    // TODO: The type checker seems to think that the isolation here is
-    // nonisolated instead of custom actor isolated.
-    print(ns) // expected-tns-warning {{sending 'ns' risks causing data races}}
-    // expected-tns-note @-1 {{global actor 'CustomActor'-isolated 'ns' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
-    // expected-complete-warning @-2 {{capture of 'ns' with non-sendable type 'NonSendableKlass' in a '@Sendable' closure}}
+    print(ns) // expected-warning {{sending 'ns' risks causing data races}}
+    // expected-note @-1 {{global actor 'CustomActor'-isolated 'ns' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later global actor 'CustomActor'-isolated uses}}
+   
   }
 
   useValue(ns)
@@ -218,7 +218,7 @@ struct Clock {
 @MainActor func testGlobalAndGlobalIsolatedPartialApplyMatch() {
   let ns = mainActorIsolatedGlobal
 
-  // This is not a transfer since ns is already main actor isolated.
+  // This is not a transfer since ns is already MainActor isolated.
   let _ = { @MainActor in
     print(ns)
   }
@@ -230,7 +230,7 @@ struct Clock {
   var ns = (NonSendableKlass(), NonSendableKlass())
   ns.0 = mainActorIsolatedGlobal
 
-  // This is not a transfer since ns is already main actor isolated.
+  // This is not a transfer since ns is already MainActor isolated.
   let _ = { @MainActor in
     print(ns)
   }
@@ -245,7 +245,7 @@ struct Clock {
     print(ns)
   }
 
-  // Since useValue is running in an actor isolated context, it is ok to use the
+  // Since useValue is running in an actor-isolated context, it is ok to use the
   // transferred value 'ns' here.
   useValue(ns)
 }
@@ -257,28 +257,28 @@ struct Clock {
 
   let erased: () -> Void = closure
 
-  await useValueAsync(erased) // expected-tns-warning {{sending 'erased' risks causing data races}}
-  // expected-tns-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '() -> Void' outside of main actor-isolated context may introduce data races}}
-  // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  await useValueAsync(erased) // expected-ni-warning {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+ 
+ 
 }
 
 @MainActor func synchronousActorIsolatedFunctionError() async {
   let erased: () -> Void = mainActorFunction
 
-  await useValueAsync(erased) // expected-tns-warning {{sending 'erased' risks causing data races}}
-  // expected-tns-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '() -> Void' outside of main actor-isolated context may introduce data races}}
-  // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  await useValueAsync(erased) // expected-ni-warning {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+ 
+ 
 }
 
 @MainActor func synchronousActorIsolatedGenericFunctionError<T>(_ t: T) async {
   let erased: (T) -> Void = useValueMainActor
 
-  await useValueAsync(erased) // expected-tns-warning {{sending 'erased' risks causing data races}}
-  // expected-tns-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '(T) -> Void' outside of main actor-isolated context may introduce data races}}
-  // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  await useValueAsync(erased) // expected-ni-warning {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+ 
+ 
 }
 
 @MainActor func synchronousActorIsolatedClassMethodError() async {
@@ -289,10 +289,10 @@ struct Clock {
   let t = Test()
   let erased: () -> Void = t.foo
 
-  await useValueAsync(erased) // expected-tns-warning {{sending 'erased' risks causing data races}}
-  // expected-tns-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '() -> Void' outside of main actor-isolated context may introduce data races}}
-  // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  await useValueAsync(erased) // expected-ni-warning {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+ 
+ 
 }
 
 @MainActor func synchronousActorIsolatedFinalClassMethodError() async {
@@ -303,10 +303,10 @@ struct Clock {
   let t = Test()
   let erased: () -> Void = t.foo
 
-  await useValueAsync(erased) // expected-tns-warning {{sending 'erased' risks causing data races}}
-  // expected-tns-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '() -> Void' outside of main actor-isolated context may introduce data races}}
-  // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  await useValueAsync(erased) // expected-ni-warning {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+ 
+ 
 }
 
 @MainActor func synchronousClosureCapturingGlobalActorIsolatedGlobal() async {
@@ -314,18 +314,48 @@ struct Clock {
     print(mainActorIsolatedGlobal)
   }
   // Regions: [{(closure), @MainActor}]
-  await transferToCustomActor(closure) // expected-tns-warning {{sending 'closure' risks causing data races}}
-  // expected-tns-note @-1 {{sending main actor-isolated 'closure' to global actor 'CustomActor'-isolated global function 'transferToCustomActor' risks causing data races between global actor 'CustomActor'-isolated and main actor-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '() -> ()' into global actor 'CustomActor'-isolated context may introduce data races}}
-  // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  await transferToCustomActor(closure) // expected-warning {{sending 'closure' risks causing data races}}
+  // expected-note @-1 {{sending main actor-isolated 'closure' to global actor 'CustomActor'-isolated global function 'transferToCustomActor' risks causing data races between global actor 'CustomActor'-isolated and main actor-isolated uses}}
+ 
+ 
 }
 
 @MainActor func synchronousClosureCapturingGlobalActorIsolatedFunction() async {
   let closure = {
     mainActorFunction()
   }
-  await transferToCustomActor(closure) // expected-tns-warning {{sending 'closure' risks causing data races}}
-  // expected-tns-note @-1 {{sending main actor-isolated 'closure' to global actor 'CustomActor'-isolated global function 'transferToCustomActor' risks causing data races between global actor 'CustomActor'-isolated and main actor-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type '() -> ()' into global actor 'CustomActor'-isolated context may introduce data races}}
-  // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  await transferToCustomActor(closure) // expected-warning {{sending 'closure' risks causing data races}}
+  // expected-note @-1 {{sending main actor-isolated 'closure' to global actor 'CustomActor'-isolated global function 'transferToCustomActor' risks causing data races between global actor 'CustomActor'-isolated and main actor-isolated uses}}
+ 
+ 
+}
+
+@MainActor
+func localCaptureDataRace5() {
+  var x = 0
+  _ = x
+
+  Task.detached { @CustomActor in x = 1 } // expected-warning {{sending 'x' risks causing data races}}
+  // expected-note @-1 {{'x' is captured by a global actor 'CustomActor'-isolated closure. global actor 'CustomActor'-isolated uses in closure may race against later main actor-isolated uses}}
+
+  x = 2 // expected-note {{access can happen concurrently}}
+}
+
+func inferLocationOfCapturedActorIsolatedSelfCorrectly() {
+  class A {
+    var block:  @MainActor () -> Void = {}
+  }
+  @CustomActor
+  class B {
+    let a = A()
+
+    func d() {
+      a.block = c // expected-warning {{converting non-Sendable function value to '@MainActor @Sendable () -> Void' may introduce data races}}
+      // expected-warning @-1 {{non-Sendable '@MainActor () -> ()'-typed result can not be returned from main actor-isolated function to global actor 'CustomActor'-isolated context}}
+      // expected-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+    }
+
+    @MainActor
+    func c() {}
+  }
 }
diff --git a/test/Concurrency/transfernonsendable_global_actor_nonsendable.swift b/test/Concurrency/transfernonsendable_global_actor_nonsendable.swift
index f4fe9669ef6af..b6553a9cc6807 100644
--- a/test/Concurrency/transfernonsendable_global_actor_nonsendable.swift
+++ b/test/Concurrency/transfernonsendable_global_actor_nonsendable.swift
@@ -1,4 +1,5 @@
 // RUN: %target-swift-frontend -emit-sil -swift-version 6 -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -parse-as-library
+// RUN: %target-swift-frontend -emit-sil -swift-version 6 -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -parse-as-library -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // READ THIS: This test is testing specifically behavior around global actor
 // isolated types that are nonsendable. This is a bit of a corner case so we use
@@ -6,6 +7,7 @@
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
diff --git a/test/Concurrency/transfernonsendable_global_actor_sending.swift b/test/Concurrency/transfernonsendable_global_actor_sending.swift
index a0fe45df8881c..37c446a1eee62 100644
--- a/test/Concurrency/transfernonsendable_global_actor_sending.swift
+++ b/test/Concurrency/transfernonsendable_global_actor_sending.swift
@@ -1,9 +1,13 @@
 // RUN: %target-swift-frontend -emit-sil -swift-version 6 -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -parse-as-library
+// RUN: %target-swift-frontend -emit-sil -swift-version 6 -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -parse-as-library -enable-upcoming-feature NonisolatedNonsendingByDefault
+
 
 // README: Once we loosen the parser so that sending is rejected in Sema
 // instead of the parser, move into the normal
 // transfernonsendable_global_actor.swift
 
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
 ////////////////////////
 // MARK: Declarations //
 ////////////////////////
@@ -30,9 +34,8 @@ func useValue<T>(_ t: T) {}
 @MainActor func testGlobalFakeInit() {
   let ns = NonSendableKlass()
 
-  // Will be resolved once @MainActor is @Sendable.
-  Task.fakeInit { @MainActor in // expected-error {{passing closure as a 'sending' parameter risks causing data races between main actor-isolated code and concurrent execution of the closure}}
-    print(ns) // expected-note {{closure captures 'ns' which is accessible to main actor-isolated code}}
+  Task.fakeInit { @MainActor in
+    print(ns)
   }
 
   useValue(ns)
diff --git a/test/Concurrency/transfernonsendable_global_actor_swift6.swift b/test/Concurrency/transfernonsendable_global_actor_swift6.swift
index a8bf80094f830..9c18e13977c77 100644
--- a/test/Concurrency/transfernonsendable_global_actor_swift6.swift
+++ b/test/Concurrency/transfernonsendable_global_actor_swift6.swift
@@ -1,4 +1,5 @@
-// RUN: %target-swift-frontend -emit-sil -swift-version 6 -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -parse-as-library
+// RUN: %target-swift-frontend -emit-sil -swift-version 6 -target %target-swift-5.1-abi-triple -verify -verify-additional-prefix ni- %s -o /dev/null -parse-as-library
+// RUN: %target-swift-frontend -emit-sil -swift-version 6 -target %target-swift-5.1-abi-triple -verify -verify-additional-prefix ni-ns- %s -o /dev/null -parse-as-library -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // README: This is testing specific patterns around global actors that are
 // slightly different in between swift 5 and swift 6. The normal global actor
@@ -6,6 +7,7 @@
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
@@ -44,22 +46,22 @@ var booleanFlag: Bool { false }
 
   let erased: () -> Void = closure
 
-  await useValueAsync(erased) // expected-error {{sending 'erased' risks causing data races}}
-  // expected-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+  await useValueAsync(erased) // expected-ni-error {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
 }
 
 @MainActor func synchronousActorIsolatedFunctionError() async {
   let erased: () -> Void = mainActorFunction
 
-  await useValueAsync(erased) // expected-error {{sending 'erased' risks causing data races}}
-  // expected-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+  await useValueAsync(erased) // expected-ni-error {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
 }
 
 @MainActor func synchronousActorIsolatedGenericFunctionError<T>(_ t: T) async {
   let erased: (T) -> Void = useValueMainActor
 
-  await useValueAsync(erased) // expected-error {{sending 'erased' risks causing data races}}
-  // expected-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+  await useValueAsync(erased) // expected-ni-error {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
 }
 
 @MainActor func synchronousActorIsolatedClassMethodError() async {
@@ -70,8 +72,8 @@ var booleanFlag: Bool { false }
   let t = Test()
   let erased: () -> Void = t.foo
 
-  await useValueAsync(erased) // expected-error {{sending 'erased' risks causing data races}}
-  // expected-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+  await useValueAsync(erased) // expected-ni-error {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
 }
 
 @MainActor func synchronousActorIsolatedFinalClassMethodError() async {
@@ -82,6 +84,6 @@ var booleanFlag: Bool { false }
   let t = Test()
   let erased: () -> Void = t.foo
 
-  await useValueAsync(erased) // expected-error {{sending 'erased' risks causing data races}}
-  // expected-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
+  await useValueAsync(erased) // expected-ni-error {{sending 'erased' risks causing data races}}
+  // expected-ni-note @-1 {{sending main actor-isolated 'erased' to nonisolated global function 'useValueAsync' risks causing data races between nonisolated and main actor-isolated uses}}
 }
diff --git a/test/Concurrency/transfernonsendable_initializers.swift b/test/Concurrency/transfernonsendable_initializers.swift
index 963734317cc9d..9e994e712b168 100644
--- a/test/Concurrency/transfernonsendable_initializers.swift
+++ b/test/Concurrency/transfernonsendable_initializers.swift
@@ -1,7 +1,9 @@
-// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -swift-version 6 -verify %s -o /dev/null
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -swift-version 6 -verify -verify-additional-prefix ni- %s -o /dev/null
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -swift-version 6 -verify -verify-additional-prefix ni-ns- %s -o /dev/null -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // This test validates the behavior of transfernonsendable around initializers.
 
@@ -34,7 +36,8 @@ actor ActorWithSynchronousNonIsolatedInit {
     // TODO: This should say actor isolated.
     let _ = { @MainActor in
       print(newK) // expected-error {{sending 'newK' risks causing data races}}
-      // expected-note @-1 {{task-isolated 'newK' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+      // expected-ni-note @-1 {{task-isolated 'newK' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+      // expected-ni-ns-note @-2 {{task-isolated 'newK' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
     }
   }
 
@@ -81,10 +84,9 @@ func initActorWithSyncNonIsolatedInit2(_ k: NonSendableKlass) {
 
 actor ActorWithAsyncIsolatedInit {
   init(_ newK: NonSendableKlass) async {
-    // TODO: This should say actor isolated.
     let _ = { @MainActor in
       print(newK) // expected-error {{sending 'newK' risks causing data races}}
-      // expected-note @-1 {{'self'-isolated 'newK' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+      // expected-note @-1 {{'self'-isolated 'newK' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later actor-isolated uses}}
     }
   }
 }
@@ -110,7 +112,7 @@ func initActorWithAsyncIsolatedInit2(_ k: NonSendableKlass) async {
 }
 
 ////////////////////////////////
-// MARK: Actor Isolated Class //
+// MARK: Actor-Isolated Class //
 ////////////////////////////////
 
 @CustomActor
@@ -150,7 +152,7 @@ class ClassWithAsyncIsolatedInit {
   init(_ newK: NonSendableKlass) async {
     let _ = { @MainActor in
       print(newK) // expected-error {{sending 'newK' risks causing data races}}
-      // expected-note @-1 {{global actor 'CustomActor'-isolated 'newK' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+      // expected-note @-1 {{global actor 'CustomActor'-isolated 'newK' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later global actor 'CustomActor'-isolated uses}}
     }
   }
 }
diff --git a/test/Concurrency/transfernonsendable_instruction_matching.sil b/test/Concurrency/transfernonsendable_instruction_matching.sil
index fcd1afa40365f..1141eece8b170 100644
--- a/test/Concurrency/transfernonsendable_instruction_matching.sil
+++ b/test/Concurrency/transfernonsendable_instruction_matching.sil
@@ -1,7 +1,6 @@
-// RUN: %target-sil-opt -send-non-sendable -enable-upcoming-feature RegionBasedIsolation -strict-concurrency=complete %s -verify -o /dev/null
+// RUN: %target-sil-opt -send-non-sendable -strict-concurrency=complete %s -verify -o /dev/null
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // PLEASE READ THIS!
 //
diff --git a/test/Concurrency/transfernonsendable_instruction_matching_opaquevalues.sil b/test/Concurrency/transfernonsendable_instruction_matching_opaquevalues.sil
index 77df2c31e810a..da917f9da555c 100644
--- a/test/Concurrency/transfernonsendable_instruction_matching_opaquevalues.sil
+++ b/test/Concurrency/transfernonsendable_instruction_matching_opaquevalues.sil
@@ -1,8 +1,7 @@
-// RUN: %target-sil-opt -send-non-sendable -enable-sil-opaque-values -enable-upcoming-feature RegionBasedIsolation -strict-concurrency=complete %s -verify -o /dev/null
+// RUN: %target-sil-opt -send-non-sendable -enable-sil-opaque-values -strict-concurrency=complete %s -verify -o /dev/null
 
 // REQUIRES: concurrency
 // REQUIRES: objc_interop
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 // PLEASE READ THIS!
 //
diff --git a/test/Concurrency/transfernonsendable_isolationcrossing_partialapply.swift b/test/Concurrency/transfernonsendable_isolationcrossing_partialapply.swift
index c24a94e778149..0a293980726a1 100644
--- a/test/Concurrency/transfernonsendable_isolationcrossing_partialapply.swift
+++ b/test/Concurrency/transfernonsendable_isolationcrossing_partialapply.swift
@@ -1,7 +1,9 @@
 // RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -disable-availability-checking -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -disable-availability-checking -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // This test validates how we handle partial applies that are isolated to a
 // specific isolation domain (causing isolation crossings to occur).
diff --git a/test/Concurrency/transfernonsendable_nonisolated.swift b/test/Concurrency/transfernonsendable_nonisolated.swift
index 73aaf5b82225e..6e208f6a2bb54 100644
--- a/test/Concurrency/transfernonsendable_nonisolated.swift
+++ b/test/Concurrency/transfernonsendable_nonisolated.swift
@@ -1,7 +1,9 @@
 // RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // This test validates behavior of transfernonsendable around nonisolated
 // functions and fields.
diff --git a/test/Concurrency/transfernonsendable_nonisolatedunsafe.swift b/test/Concurrency/transfernonsendable_nonisolatedunsafe.swift
index 5b67379d2ab1c..d9df955950355 100644
--- a/test/Concurrency/transfernonsendable_nonisolatedunsafe.swift
+++ b/test/Concurrency/transfernonsendable_nonisolatedunsafe.swift
@@ -1,16 +1,18 @@
-// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify -verify-additional-prefix tns-  %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // READ THIS: This test is intended to centralize all tests that use
 // nonisolated(unsafe).
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
 ////////////////////////
 
-class NonSendableKlass { // expected-complete-note 98{{}}
+class NonSendableKlass {
   var field: NonSendableKlass? = nil
 }
 
@@ -52,38 +54,38 @@ func transferLetNonTransferrableSquelched(_ ns: NonSendableKlass) async {
   let ns4 = ns
 
   await transferToMainDirect(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainDirect(ns2)
 
   await transferToMainDirect(ns3)
-  // expected-tns-warning @-1 {{sending 'ns3' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns3' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainDirect(ns4)
-  // expected-tns-warning @-1 {{sending 'ns4' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns4' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns2)
 
   await transferToMainIndirect(ns3)
-  // expected-tns-warning @-1 {{sending 'ns3' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns3' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns4)
-  // expected-tns-warning @-1 {{sending 'ns4' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns4' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 }
 
 func useAfterTransferLetSquelchedDirect() async {
@@ -93,25 +95,25 @@ func useAfterTransferLetSquelchedDirect() async {
   let ns4 = ns
 
   await transferToMainDirect(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  print(ns) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending 'ns' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  print(ns) // expected-note {{access can happen concurrently}}
 
   await transferToMainDirect(ns2)
   print(ns2)
 
   await transferToMainDirect(ns3)
-  // expected-tns-warning @-1 {{sending 'ns3' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  print(ns3) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns3' risks causing data races}}
+  // expected-note @-2 {{sending 'ns3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  print(ns3) // expected-note {{access can happen concurrently}}
 
   await transferToMainDirect(ns4)
-  // expected-tns-warning @-1 {{sending 'ns4' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns4' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  print(ns4) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns4' risks causing data races}}
+  // expected-note @-2 {{sending 'ns4' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  print(ns4) // expected-note {{access can happen concurrently}}
 }
 
 func useAfterTransferSquelchedIndirect() async {
@@ -121,25 +123,25 @@ func useAfterTransferSquelchedIndirect() async {
   let ns4 = ns
 
   await transferToMainIndirect(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  print(ns) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  print(ns) // expected-note {{access can happen concurrently}}
 
   await transferToMainIndirect(ns2)
   print(ns2)
 
   await transferToMainIndirect(ns3)
-  // expected-tns-warning @-1 {{sending 'ns3' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  print(ns3) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns3' risks causing data races}}
+  // expected-note @-2 {{sending 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  print(ns3) // expected-note {{access can happen concurrently}}
 
   await transferToMainIndirect(ns4)
-  // expected-tns-warning @-1 {{sending 'ns4' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  print(ns4) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns4' risks causing data races}}
+  // expected-note @-2 {{sending 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  print(ns4) // expected-note {{access can happen concurrently}}
 }
 
 // We consider the klass field separate from the klass, so we get an error.
@@ -147,13 +149,13 @@ func transferNonTransferrableClassField(_ ns: NonSendableKlass) async {
   nonisolated(unsafe) let ns2 = ns
 
   await transferToMainDirect(ns2.field!)
-  // expected-tns-warning @-1 {{sending 'ns2.field' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns2.field' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   await transferToMainIndirect(ns2.field!)
-  // expected-tns-warning @-1 {{sending 'ns2.field' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns2.field' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 }
 
 // We consider the klass field separate from the klass, so we get an error.
@@ -164,19 +166,19 @@ func transferNonTransferrableStructField(_ ns: NonSendableStruct) async {
   await transferToMainIndirect(ns2)
 
   await transferToMainDirect(ns2.field!)
-  // expected-tns-warning @-1 {{sending 'ns2.field' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns2.field' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns2.field!)
-  // expected-tns-warning @-1 {{sending 'ns2.field' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns2.field' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns2.field)
-  // expected-tns-warning @-1 {{sending 'ns2.field' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass?' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns2.field' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns2.field' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass?' into main actor-isolated context may introduce data races}}
 }
 
 // Make sure that we pattern match the consuming temporary correctly.
@@ -184,14 +186,14 @@ func testConsumingTransfer(_ ns: NonSendableKlass) async {
   nonisolated(unsafe) let ns2 = ns
 
   await transferToMainDirectConsuming(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainDirectConsuming' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainDirectConsuming' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirectConsuming(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainIndirectConsuming' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainIndirectConsuming' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainDirectConsuming(ns2)
 
@@ -207,38 +209,38 @@ func transferVarNonTransferrableSquelched(_ ns: NonSendableKlass) async {
   let ns4 = ns
 
   await transferToMainDirect(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainDirect(ns2)
 
   await transferToMainDirect(ns3)
-  // expected-tns-warning @-1 {{sending 'ns3' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns3' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainDirect(ns4)
-  // expected-tns-warning @-1 {{sending 'ns4' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns4' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns2)
 
   await transferToMainIndirect(ns3)
-  // expected-tns-warning @-1 {{sending 'ns3' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns3' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns4)
-  // expected-tns-warning @-1 {{sending 'ns4' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns4' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 }
 
 func useAfterTransferVarSquelchedDirect() async {
@@ -249,25 +251,25 @@ func useAfterTransferVarSquelchedDirect() async {
   let ns4 = ns
 
   await transferToMainDirect(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  print(ns) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending 'ns' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  print(ns) // expected-note {{access can happen concurrently}}
 
   await transferToMainDirect(ns2)
   print(ns2)
 
   await transferToMainDirect(ns3)
-  // expected-tns-warning @-1 {{sending 'ns3' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  print(ns3) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns3' risks causing data races}}
+  // expected-note @-2 {{sending 'ns3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  print(ns3) // expected-note {{access can happen concurrently}}
 
   await transferToMainDirect(ns4)
-  // expected-tns-warning @-1 {{sending 'ns4' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns4' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-  print(ns4) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns4' risks causing data races}}
+  // expected-note @-2 {{sending 'ns4' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  print(ns4) // expected-note {{access can happen concurrently}}
 }
 
 //////////////////////////////
@@ -282,21 +284,21 @@ func transferLetNonTransferrableSquelchedAddressOnly<T>(_ ns: T) async { // expe
   let ns4 = ns
 
   await transferToMainIndirect(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'T' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'T' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns2)
 
   await transferToMainIndirect(ns3)
-  // expected-tns-warning @-1 {{sending 'ns3' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'T' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns3' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'T' into main actor-isolated context may introduce data races}}
 
   await transferToMainIndirect(ns4)
-  // expected-tns-warning @-1 {{sending 'ns4' risks causing data races}}
-  // expected-tns-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'T' into main actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'ns4' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'T' into main actor-isolated context may introduce data races}}
 }
 
 func useAfterTransferLetSquelchedIndirectAddressOnly<T : ProvidesStaticValue>(_ meta: T.Type) async { // expected-complete-note 3{{}}
@@ -306,25 +308,25 @@ func useAfterTransferLetSquelchedIndirectAddressOnly<T : ProvidesStaticValue>(_
   let ns4 = ns
 
   await transferToMainIndirect(ns)
-  // expected-tns-warning @-1 {{sending 'ns' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'T' into main actor-isolated context may introduce data races}}
-  print(ns) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'T' into main actor-isolated context may introduce data races}}
+  print(ns)
 
   await transferToMainIndirect(ns2)
   print(ns2)
 
   await transferToMainIndirect(ns3)
-  // expected-tns-warning @-1 {{sending 'ns3' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'T' into main actor-isolated context may introduce data races}}
-  print(ns3) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns3' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns3' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'T' into main actor-isolated context may introduce data races}}
+  print(ns3)
 
   await transferToMainIndirect(ns4)
-  // expected-tns-warning @-1 {{sending 'ns4' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-3 {{passing argument of non-sendable type 'T' into main actor-isolated context may introduce data races}}
-  print(ns4) // expected-tns-note {{access can happen concurrently}}
+  // expected-warning @-1 {{sending 'ns4' risks causing data races}}
+  // expected-note @-2 {{sending task-isolated 'ns4' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-3 {{passing argument of non-Sendable type 'T' into main actor-isolated context may introduce data races}}
+  print(ns4)
 }
 
 ////////////////////////
@@ -338,13 +340,13 @@ struct Globals {
 
 func testAccessStaticGlobals() async {
   await transferToMainDirect(Globals.nonIsolatedUnsafeLetObject)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   await transferToMainIndirect(Globals.nonIsolatedUnsafeLetObject)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   await transferToMainDirect(Globals.nonIsolatedUnsafeVarObject)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   await transferToMainIndirect(Globals.nonIsolatedUnsafeVarObject)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 }
 
 nonisolated(unsafe) let globalNonIsolatedUnsafeLetObject = NonSendableKlass()
@@ -382,19 +384,19 @@ actor MyActor {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     let x = nonIsolatedUnsafeLetObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 }
 
@@ -404,19 +406,19 @@ final actor MyFinalActor {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     let x = nonIsolatedUnsafeLetObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending 'self'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 }
 
@@ -427,13 +429,13 @@ final class FinalNonIsolatedUnsafeFieldKlassSendable: @unchecked Sendable {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     // 'x' is treated as disconnected since we treat unchecked fields as being
     // disconnected.
@@ -441,10 +443,10 @@ final class FinalNonIsolatedUnsafeFieldKlassSendable: @unchecked Sendable {
     // TODO: Is this correct?
     let x = nonIsolatedLetObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-    print(x) // expected-tns-note {{access can happen concurrently}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    print(x) // expected-note {{access can happen concurrently}}
   }
 }
 
@@ -454,13 +456,13 @@ class NonIsolatedUnsafeFieldKlassSendable: @unchecked Sendable {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     // 'x' is treated as disconnected since we treat unchecked fields as being
     // disconnected.
@@ -468,10 +470,10 @@ class NonIsolatedUnsafeFieldKlassSendable: @unchecked Sendable {
     // TODO: Is this correct?
     let x = nonIsolatedUnsafeLetObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-    print(x) // expected-tns-note {{access can happen concurrently}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    print(x) // expected-note {{access can happen concurrently}}
   }
 }
 
@@ -481,13 +483,13 @@ struct NonIsolatedUnsafeFieldStruct: Sendable {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     // 'x' is treated as disconnected since we treat unchecked fields as being
     // disconnected.
@@ -495,10 +497,10 @@ struct NonIsolatedUnsafeFieldStruct: Sendable {
     // TODO: Is this correct?
     let x = nonIsolatedUnsafeLetObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-    print(x) // expected-tns-note {{access can happen concurrently}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    print(x) // expected-note {{access can happen concurrently}}
   }
 }
 
@@ -511,9 +513,9 @@ enum NonIsolatedUnsafeComputedEnum: Sendable {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     // 'x' is treated as disconnected since we treat unchecked fields as being
     // disconnected.
@@ -521,10 +523,10 @@ enum NonIsolatedUnsafeComputedEnum: Sendable {
     // TODO: Is this correct?
     let x = nonIsolatedUnsafeVarObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
-    print(x) // expected-tns-note {{access can happen concurrently}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    print(x) // expected-note {{access can happen concurrently}}
   }
 }
 
@@ -535,20 +537,20 @@ enum NonIsolatedUnsafeComputedEnum: Sendable {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     // 'x' is treated as global actor 'CustomActor' isolated.
     let x = nonIsolatedLetObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     print(x)
   }
 }
@@ -559,21 +561,21 @@ enum NonIsolatedUnsafeComputedEnum: Sendable {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     // x is treated as global actor 'CustomActor' isolated since the
     // nonisolated(unsafe) only applies to nonIsolatedUnsafeLetObject.
     let x = nonIsolatedUnsafeLetObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     print(x)
   }
 }
@@ -584,20 +586,20 @@ enum NonIsolatedUnsafeComputedEnum: Sendable {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     // 'x' is treated as global actor 'CustomActor'-isolated.
     let x = nonIsolatedUnsafeLetObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     print(x)
   }
 }
@@ -612,32 +614,32 @@ enum NonIsolatedUnsafeComputedEnum: Sendable {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     // 'x' is treated as global actor 'CustomActor'-isolated.
     let x = nonIsolatedUnsafeLetObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     let x2 = nonIsolatedUnsafeVarObject
     await transferToMainDirect(x2)
-    // expected-tns-warning @-1 {{sending 'x2' risks causing data races}}
-    // expected-tns-note @-2 {{sending global actor 'CustomActor'-isolated 'x2' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x2' risks causing data races}}
+    // expected-note @-2 {{sending global actor 'CustomActor'-isolated 'x2' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     let x3 = nonIsolatedUnsafeVarComputedObject
     await transferToMainDirect(x3)
-    // expected-tns-warning @-1 {{sending 'x3' risks causing data races}}
-    // expected-tns-note @-2 {{sending global actor 'CustomActor'-isolated 'x3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x3' risks causing data races}}
+    // expected-note @-2 {{sending global actor 'CustomActor'-isolated 'x3' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     print(x)
   }
@@ -652,17 +654,17 @@ enum NonIsolatedUnsafeComputedEnum: Sendable {
 
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
 
     // 'x' is treated as global actor 'CustomActor' even though
     // nonIsolatedUnsafeVarObject is not.
     let x = nonIsolatedUnsafeVarObject
     await transferToMainDirect(x)
-    // expected-tns-warning @-1 {{sending 'x' risks causing data races}}
-    // expected-tns-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'x' risks causing data races}}
+    // expected-note @-2 {{sending global actor 'CustomActor'-isolated 'x' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and global actor 'CustomActor'-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     print(x)
   }
 }
@@ -676,24 +678,24 @@ struct NonIsolatedUnsafeFieldNonSendableStruct {
   let letObject = NonSendableKlass()
   var varObject = NonSendableKlass()
 
-  // This is unsafe since self is not main actor isolated, so our values are
+  // This is unsafe since self is not MainActor isolated, so our values are
   // task isolated.
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(letObject)
-    // expected-tns-warning @-1 {{sending 'self.letObject' risks causing data races}}
-    // expected-tns-note @-2 {{sending task-isolated 'self.letObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'self.letObject' risks causing data races}}
+    // expected-note @-2 {{sending task-isolated 'self.letObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(varObject)
-    // expected-tns-warning @-1 {{sending 'self.varObject' risks causing data races}}
-    // expected-tns-note @-2 {{sending task-isolated 'self.varObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'self.varObject' risks causing data races}}
+    // expected-note @-2 {{sending task-isolated 'self.varObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 
-  // This is safe since self will become main actor isolated as a result of
+  // This is safe since self will become MainActor isolated as a result of
   // test2 running.
   @MainActor func test2() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
@@ -709,24 +711,24 @@ final class FinalNonIsolatedUnsafeFieldKlass {
   let letObject = NonSendableKlass()
   var varObject = NonSendableKlass()
 
-  // This is unsafe since self is not main actor isolated, so our values are
+  // This is unsafe since self is not MainActor isolated, so our values are
   // task isolated.
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(letObject)
-    // expected-tns-warning @-1 {{sending 'self.letObject' risks causing data races}}
-    // expected-tns-note @-2 {{sending task-isolated 'self.letObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'self.letObject' risks causing data races}}
+    // expected-note @-2 {{sending task-isolated 'self.letObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(varObject)
-    // expected-tns-warning @-1 {{sending 'self.varObject' risks causing data races}}
-    // expected-tns-note @-2 {{sending task-isolated 'self.varObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'self.varObject' risks causing data races}}
+    // expected-note @-2 {{sending task-isolated 'self.varObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 
-  // This is safe since self will become main actor isolated as a result of
+  // This is safe since self will become MainActor isolated as a result of
   // test2 running.
   @MainActor func test2() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
@@ -742,24 +744,24 @@ class NonIsolatedUnsafeFieldKlass {
   let letObject = NonSendableKlass()
   var varObject = NonSendableKlass()
 
-  // This is unsafe since self is not main actor isolated, so our values are
+  // This is unsafe since self is not MainActor isolated, so our values are
   // task isolated.
   func test() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(nonIsolatedUnsafeVarObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(letObject)
-    // expected-tns-warning @-1 {{sending 'self.letObject' risks causing data races}}
-    // expected-tns-note @-2 {{sending task-isolated 'self.letObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'self.letObject' risks causing data races}}
+    // expected-note @-2 {{sending task-isolated 'self.letObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainDirect(varObject)
-    // expected-tns-warning @-1 {{sending 'self.varObject' risks causing data races}}
-    // expected-tns-note @-2 {{sending task-isolated 'self.varObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'self.varObject' risks causing data races}}
+    // expected-note @-2 {{sending task-isolated 'self.varObject' to main actor-isolated global function 'transferToMainDirect' risks causing data races between main actor-isolated and task-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
   }
 
-  // This is safe since self will become main actor isolated as a result of
+  // This is safe since self will become MainActor isolated as a result of
   // test2 running.
   @MainActor func test2() async {
     await transferToMainDirect(nonIsolatedUnsafeLetObject)
@@ -775,28 +777,28 @@ class NonIsolatedUnsafeFieldGenericKlass<T> { // expected-complete-note 4{{}}
   let letAddressOnly: T? = nil
   var varAddressOnly: T? = nil
 
-  // This is unsafe since self is not main actor isolated, so our values are
+  // This is unsafe since self is not MainActor isolated, so our values are
   // task isolated.
   func test() async {
     await transferToMainIndirect(nonIsolatedUnsafeLetAddressOnly)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'T?' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'T?' into main actor-isolated context may introduce data races}}
 
     await transferToMainIndirect(nonIsolatedUnsafeVarAddressOnly)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'T?' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'T?' into main actor-isolated context may introduce data races}}
 
     await transferToMainIndirect(letAddressOnly)
-    // expected-tns-warning @-1 {{sending 'self.letAddressOnly' risks causing data races}}
-    // expected-tns-note @-2 {{sending task-isolated 'self.letAddressOnly' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'T?' into main actor-isolated context may introduce data races}}
+    // expected-warning @-1 {{sending 'self.letAddressOnly' risks causing data races}}
+    // expected-note @-2 {{sending task-isolated 'self.letAddressOnly' to main actor-isolated global function 'transferToMainIndirect' risks causing data races between main actor-isolated and task-isolated uses}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'T?' into main actor-isolated context may introduce data races}}
 
     // TODO: This diagnostic is unfortunate since we are erroring on the
     // temporary created by the class_method call.
     await transferToMainIndirect(varAddressOnly)
-    // expected-tns-warning @-1 {{sending value of non-Sendable type 'T?' risks causing data races}}
-    // expected-tns-note @-2 {{sending task-isolated value of non-Sendable type 'T?' to main actor-isolated global function 'transferToMainIndirect' risks causing races in between task-isolated and main actor-isolated uses}}
+    // expected-warning @-1 {{sending value of non-Sendable type 'T?' risks causing data races}}
+    // expected-note @-2 {{sending task-isolated value of non-Sendable type 'T?' to main actor-isolated global function 'transferToMainIndirect' risks causing races in between task-isolated and main actor-isolated uses}}
   }
 
-  // This is safe since self will become main actor isolated as a result of
+  // This is safe since self will become MainActor isolated as a result of
   // test2 running.
   @MainActor func test2() async {
     await transferToMainIndirect(nonIsolatedUnsafeLetAddressOnly)
@@ -815,9 +817,229 @@ actor ActorContainingSendableStruct {
 
   func test() async {
     await transferToMainDirect(x!.nonIsolatedUnsafeLetObject)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
     await transferToMainIndirect(x)
   }
 }
 
 
+////////////////////
+// MARK: Closures //
+////////////////////
+
+func closureTests() async {
+  func sendingClosure(_ x: sending () -> ()) {
+  }
+
+  func testLetOneNSVariableError() async {
+    let x = NonSendableKlass()
+    sendingClosure { _ = x } // expected-warning {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+    // expected-note @-1 {{Passing value of non-Sendable type '() -> ()' as a 'sending' argument to local function 'sendingClosure' risks causing races in between local and caller code}}
+    sendingClosure { _ = x } // expected-note {{access can happen concurrently}}
+  }
+
+  func testLetNonIsolatedUnsafeNSVariableNoError() async {
+    nonisolated(unsafe) let x = NonSendableKlass()
+    sendingClosure { _ = x }
+    sendingClosure { _ = x }
+  }
+
+  func testLetOneNSVariableSVariableError() async {
+    let x = NonSendableKlass()
+    let y = CustomActorInstance()
+    sendingClosure { // expected-warning {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+      // expected-note @-1 {{Passing value of non-Sendable type '() -> ()' as a 'sending' argument to local function 'sendingClosure' risks causing races in between local and caller code}}
+      _ = x
+      _ = y
+    }
+    sendingClosure { // expected-note {{access can happen concurrently}}
+      _ = x
+      _ = y
+    }
+  }
+
+  func testLetNonIsolatedUnsafeNSSVariableNoError() async {
+    nonisolated(unsafe) let x = NonSendableKlass()
+    let y = CustomActorInstance()
+    sendingClosure {
+      _ = x
+      _ = y
+    }
+    sendingClosure {
+      _ = x
+      _ = y
+    }
+  }
+
+  func testLetTwoNSVariableError() async {
+    let x = NonSendableKlass()
+    let y = NonSendableKlass()
+    sendingClosure { // expected-warning {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+      // expected-note @-1 {{Passing value of non-Sendable type '() -> ()' as a 'sending' argument to local function 'sendingClosure' risks causing races in between local and caller code}}
+      _ = x
+      _ = y
+    }
+    sendingClosure { // expected-note {{access can happen concurrently}}
+      _ = x
+      _ = y
+    }
+  }
+
+  func testLetTwoNSVariableError2() async {
+    nonisolated(unsafe) let x = NonSendableKlass()
+    let y = NonSendableKlass()
+    sendingClosure { // expected-warning {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+      // expected-note @-1 {{Passing value of non-Sendable type '() -> ()' as a 'sending' argument to local function 'sendingClosure' risks causing races in between local and caller code}}
+      _ = x
+      _ = y
+    }
+    sendingClosure { // expected-note {{access can happen concurrently}}
+      _ = x
+      _ = y
+    }
+  }
+
+  func testLetTwoNSVariableError3() async {
+    nonisolated(unsafe) let x = NonSendableKlass()
+    nonisolated(unsafe) let y = NonSendableKlass()
+    sendingClosure {
+      _ = x
+      _ = y
+    }
+    sendingClosure {
+      _ = x
+      _ = y
+    }
+  }
+
+  func testVarOneNSVariableError() async {
+    var x = NonSendableKlass()
+    x = NonSendableKlass()
+
+    sendingClosure { _ = x } // expected-warning {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+    // expected-note @-1 {{Passing value of non-Sendable type '() -> ()' as a 'sending' argument to local function 'sendingClosure' risks causing races in between local and caller code}}
+    sendingClosure { _ = x } // expected-note {{access can happen concurrently}}
+  }
+
+  func testVarNonIsolatedUnsafeNSVariableNoError() async {
+    nonisolated(unsafe) var x = NonSendableKlass()
+    x = NonSendableKlass()
+
+    sendingClosure { _ = x }
+    sendingClosure { _ = x }
+  }
+
+  func testVarOneNSVariableSVariableError() async {
+    var x = NonSendableKlass()
+    x = NonSendableKlass()
+    var y = CustomActorInstance()
+    y = CustomActorInstance()
+    sendingClosure { // expected-warning {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+      // expected-note @-1 {{Passing value of non-Sendable type '() -> ()' as a 'sending' argument to local function 'sendingClosure' risks causing races in between local and caller code}}
+      _ = x
+      _ = y
+    }
+    sendingClosure { // expected-note {{access can happen concurrently}}
+      _ = x
+      _ = y
+    }
+  }
+
+  func testVarNonIsolatedUnsafeNSSVariableNoError() async {
+    nonisolated(unsafe) var x = NonSendableKlass()
+    x = NonSendableKlass()
+    var y = CustomActorInstance()
+    y = CustomActorInstance()
+    sendingClosure {
+      _ = x
+      _ = y
+    }
+    sendingClosure {
+      _ = x
+      _ = y
+    }
+  }
+
+  func testVarTwoNSVariableError() async {
+    var x = NonSendableKlass()
+    x = NonSendableKlass()
+    var y = NonSendableKlass()
+    y = NonSendableKlass()
+    sendingClosure { // expected-warning {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+      // expected-note @-1 {{Passing value of non-Sendable type '() -> ()' as a 'sending' argument to local function 'sendingClosure' risks causing races in between local and caller code}}
+      _ = x
+      _ = y
+    }
+    sendingClosure { // expected-note {{access can happen concurrently}}
+      _ = x
+      _ = y
+    }
+  }
+
+  func testVarTwoNSVariableError2() async {
+    nonisolated(unsafe) var x = NonSendableKlass()
+    x = NonSendableKlass()
+    var y = NonSendableKlass()
+    y = NonSendableKlass()
+    sendingClosure { // expected-warning {{sending value of non-Sendable type '() -> ()' risks causing data races}}
+      // expected-note @-1 {{Passing value of non-Sendable type '() -> ()' as a 'sending' argument to local function 'sendingClosure' risks causing races in between local and caller code}}
+      _ = x
+      _ = y
+    }
+    sendingClosure { // expected-note {{access can happen concurrently}}
+      _ = x
+      _ = y
+    }
+  }
+
+  func testVarTwoNSVariableError3() async {
+    nonisolated(unsafe) var x = NonSendableKlass()
+    x = NonSendableKlass()
+    nonisolated(unsafe) var y = NonSendableKlass()
+    y = NonSendableKlass()
+    sendingClosure {
+      _ = x
+      _ = y
+    }
+    sendingClosure {
+      _ = x
+      _ = y
+    }
+  }
+
+  func testWithTaskDetached() async {
+    let x1 = NonSendableKlass()
+    Task.detached { _ = x1 } // expected-warning {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
+    // expected-note @-1 {{Passing value of non-Sendable type '() async -> ()' as a 'sending' argument to static method 'detached(name:priority:operation:)' risks causing races in between local and caller code}}
+    Task.detached { _ = x1 } // expected-note {{access can happen concurrently}}
+
+    nonisolated(unsafe) let x2 = NonSendableKlass()
+    Task.detached { _ = x2 }
+    Task.detached { _ = x2 }
+
+    nonisolated(unsafe) let x3a = NonSendableKlass()
+    nonisolated(unsafe) let x3b = NonSendableKlass()
+    Task.detached { _ = x3a; _ = x3b }
+    Task.detached { _ = x3a; _ = x3b }
+
+    nonisolated(unsafe) let x4a = NonSendableKlass()
+    let x4b = NonSendableKlass()
+    Task.detached { _ = x4a; _ = x4b } // expected-warning {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
+    // expected-note @-1 {{Passing value of non-Sendable type '() async -> ()' as a 'sending' argument to static method 'detached(name:priority:operation:)' risks causing races in between local and caller code}}
+    Task.detached { _ = x4a; _ = x4b } // expected-note {{access can happen concurrently}}
+  }
+
+  // The reason why this works is that we do not infer nonisolated(unsafe)
+  // passed the begin_borrow [var_decl] of y. So we think the closure is
+  // nonisolated(unsafe), but its uses via the begin_borrow [var_decl] is
+  // not.
+  func testNamedClosure() async {
+    nonisolated(unsafe) let x = NonSendableKlass()
+    let y = {
+      _ = x
+    }
+    sendingClosure(y) // expected-warning {{sending 'y' risks causing data races}}
+    // expected-note @-1 {{'y' used after being passed as a 'sending' parameter}}
+    sendingClosure(y) // expected-note {{access can happen concurrently}}
+  }
+}
diff --git a/test/Concurrency/transfernonsendable_objc.swift b/test/Concurrency/transfernonsendable_objc.swift
index b726878b9c7d0..56099d5097b84 100644
--- a/test/Concurrency/transfernonsendable_objc.swift
+++ b/test/Concurrency/transfernonsendable_objc.swift
@@ -1,8 +1,9 @@
-// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation -target %target-swift-5.1-abi-triple %s -o /dev/null -import-objc-header %S/Inputs/transfernonsendable_objc.h -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple %s -o /dev/null -import-objc-header %S/Inputs/transfernonsendable_objc.h -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple %s -o /dev/null -import-objc-header %S/Inputs/transfernonsendable_objc.h -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: objc_interop
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
-// REQUIRES: swift_feature_RegionBasedIsolation
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 import Foundation
 
diff --git a/test/Concurrency/transfernonsendable_ownership.swift b/test/Concurrency/transfernonsendable_ownership.swift
index fe0fd7102e736..68bed57c74b37 100644
--- a/test/Concurrency/transfernonsendable_ownership.swift
+++ b/test/Concurrency/transfernonsendable_ownership.swift
@@ -1,4 +1,5 @@
 // RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify -enable-upcoming-feature GlobalActorIsolatedTypesUsability %s -o /dev/null
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify -enable-upcoming-feature GlobalActorIsolatedTypesUsability %s -o /dev/null -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // This test validates the behavior of transfer non sendable around ownership
 // constructs like non copyable types, consuming/borrowing parameters, and inout
@@ -6,6 +7,7 @@
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
diff --git a/test/Concurrency/transfernonsendable_preconcurrency.swift b/test/Concurrency/transfernonsendable_preconcurrency.swift
index 08f87c3fa89cf..7577948bf8c27 100644
--- a/test/Concurrency/transfernonsendable_preconcurrency.swift
+++ b/test/Concurrency/transfernonsendable_preconcurrency.swift
@@ -11,9 +11,11 @@
 
 // Test swift 6
 // RUN: %target-swift-frontend -swift-version 6 %s -emit-sil -o /dev/null -verify -verify-additional-prefix swift-6- -parse-as-library -I %t -target %target-swift-5.1-abi-triple
+// RUN: %target-swift-frontend -swift-version 6 %s -emit-sil -o /dev/null -verify -verify-additional-prefix swift-6- -parse-as-library -I %t -target %target-swift-5.1-abi-triple -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // README: This test is meant to test the interaction of transfernonsendable and
 // preconcurrency. Please only keep such tests in this file.
diff --git a/test/Concurrency/transfernonsendable_preconcurrency_sending.swift b/test/Concurrency/transfernonsendable_preconcurrency_sending.swift
index dd2d68a356723..a46ee44de1dc2 100644
--- a/test/Concurrency/transfernonsendable_preconcurrency_sending.swift
+++ b/test/Concurrency/transfernonsendable_preconcurrency_sending.swift
@@ -11,9 +11,11 @@
 
 // Test swift 6
 // RUN: %target-swift-frontend -swift-version 6 %s -emit-sil -o /dev/null -verify -verify-additional-prefix swift-6- -parse-as-library -I %t -target %target-swift-5.1-abi-triple
+// RUN: %target-swift-frontend -swift-version 6 %s -emit-sil -o /dev/null -verify -verify-additional-prefix swift-6- -parse-as-library -I %t -target %target-swift-5.1-abi-triple -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // README: This test is meant to test the interaction of transfernonsendable,
 // preconcurrency, and transferring. Please only keep such tests in this file.
diff --git a/test/Concurrency/transfernonsendable_rbi_result.swift b/test/Concurrency/transfernonsendable_rbi_result.swift
index ea730c83b2d92..16a2027741604 100644
--- a/test/Concurrency/transfernonsendable_rbi_result.swift
+++ b/test/Concurrency/transfernonsendable_rbi_result.swift
@@ -1,7 +1,9 @@
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -swift-version 6 -parse-as-library %s -emit-sil -o /dev/null -verify
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -swift-version 6 -disable-availability-checking -parse-as-library %s -emit-sil -o /dev/null -verify -verify-additional-prefix ni-
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -swift-version 6 -disable-availability-checking -parse-as-library %s -emit-sil -o /dev/null -verify -verify-additional-prefix ni-ns- -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: asserts
 // REQUIRES: concurrency
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ///////////////////////
 // MARK: Declaration //
@@ -20,9 +22,13 @@ struct CustomActor {
 class NonSendable {} // expected-note 3{{}}
 
 func passNonSendable(_: NonSendable) async { }
+func passTwoNonSendable(_: NonSendable, _: NonSendable) async { }
 
 func returnsNonSendable() async -> NonSendable { NonSendable() }
 
+@MainActor
+func sendToMain<T>(_ t: T) async {}
+
 @MainActor
 func mainActorPassNonSendable(_: NonSendable) async { }
 
@@ -93,9 +99,22 @@ actor A {
   func callNonisolatedFuncsFromActor(ns: NonSendable) async {
     // Non-sendable value passed from nonisolated to actor isolated
 
+    // We do not error in ni-ns since we just merge pass non sendable.
     await passNonSendable(ns)
-    // expected-error @-1 {{sending 'ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'ns' to nonisolated global function 'passNonSendable' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-ni-error @-1 {{sending 'ns' risks causing data races}}
+    // expected-ni-note @-2 {{sending 'self'-isolated 'ns' to nonisolated global function 'passNonSendable' risks causing data races between nonisolated and 'self'-isolated uses}}
+
+    // We error here in both modes but in different places. In NI mode, we error
+    // on passing ns to a nonisolated function. With ni-ns, we do not error
+    // there since we inherit isolation from the caller.
+    //
+    // In contrast, when ni-ns is enabled, we error on sendToMain since we merge
+    // ns2 into ns's region causing it to be self-isolated.
+    let ns2 = NonSendable()
+    await passTwoNonSendable(ns, ns2) // expected-ni-error {{sending 'ns' risks causing data races}}
+    // expected-ni-note @-1 {{sending 'self'-isolated 'ns' to nonisolated global function 'passTwoNonSendable' risks causing data races between nonisolated and 'self'-isolated uses}}
+    await sendToMain(ns2) // expected-ni-ns-error {{sending 'ns2' risks causing data races}}
+    // expected-ni-ns-note @-1 {{sending 'self'-isolated 'ns2' to main actor-isolated global function 'sendToMain' risks causing data races between main actor-isolated and 'self'-isolated uses}}
 
     _ = await returnsNonSendable()
   }
@@ -135,3 +154,8 @@ func testGenericResults() async {
   let _: NonSendable = await mainActorGenericReturnNonSendable()
   // expected-error @-1 {{non-Sendable 'NonSendable'-typed result can not be returned from main actor-isolated global function 'mainActorGenericReturnNonSendable()' to nonisolated context}}
 }
+
+// https://github.com/swiftlang/swift/issues/81534
+func testInlineArray() {
+  let _: InlineArray<_, UInt8> = [0]
+}
diff --git a/test/Concurrency/transfernonsendable_region_based_sendability.swift b/test/Concurrency/transfernonsendable_region_based_sendability.swift
index c12215a960c14..c7138801885eb 100644
--- a/test/Concurrency/transfernonsendable_region_based_sendability.swift
+++ b/test/Concurrency/transfernonsendable_region_based_sendability.swift
@@ -1,7 +1,9 @@
-// RUN: %target-swift-frontend  -strict-concurrency=complete -target %target-swift-5.1-abi-triple -parse-as-library -emit-sil -o /dev/null -verify -verify-additional-prefix tns- %s -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend  -strict-concurrency=complete -target %target-swift-5.1-abi-triple -parse-as-library -emit-sil -o /dev/null -verify %s -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend  -strict-concurrency=complete -target %target-swift-5.1-abi-triple -parse-as-library -emit-sil -o /dev/null -verify %s -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 /*
  This file tests the early features of the flow-sensitive Sendable checking implemented by the TransferNonSendable SIL pass.
@@ -57,30 +59,30 @@ func test_isolation_crossing_sensitivity(a : A) async {
   foo_noniso(ns0);
 
   // This call consumes ns1
-  await a.foo(ns1); // expected-tns-warning {{sending 'ns1' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(ns1); // expected-warning {{sending 'ns1' risks causing data races}}
+  // expected-note @-1 {{sending 'ns1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
   print(ns0);
-  print(ns1); // expected-tns-note {{access can happen concurrently}}
+  print(ns1); // expected-note {{access can happen concurrently}}
 }
 
 func test_arg_nonconsumable(a : A, ns_arg : NonSendable) async {
   let ns_let = NonSendable();
 
   // Safe to consume an rvalue.
-  await a.foo(NonSendable()); // expected-complete-warning {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(NonSendable()); // expected-complete-warning {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
   // Safe to consume an lvalue.
-  await a.foo(ns_let); // expected-complete-warning {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(ns_let); // expected-complete-warning {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
   // Not safe to consume an arg.
-  await a.foo(ns_arg); // expected-tns-warning {{sending 'ns_arg' risks causing data races}}
-  // expected-tns-note @-1 {{sending task-isolated 'ns_arg' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and task-isolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(ns_arg); // expected-warning {{sending 'ns_arg' risks causing data races}}
+  // expected-note @-1 {{sending task-isolated 'ns_arg' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and task-isolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
   // Check for no duplicate warnings once self is "consumed"
-  await a.foo(NonSendable()); // expected-complete-warning {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(NonSendable()); // expected-complete-warning {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 }
 
 func test_closure_capture(a : A) async {
@@ -103,42 +105,42 @@ func test_closure_capture(a : A) async {
 
   // this should consume ns0
   await a.run_closure(captures0)
-  // expected-tns-warning @-1 {{sending 'captures0' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'captures0' to actor-isolated instance method 'run_closure' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-warning @-1 {{sending 'captures0' risks causing data races}}
+  // expected-note @-2 {{sending 'captures0' to actor-isolated instance method 'run_closure' risks causing data races between actor-isolated and local nonisolated uses}}
 
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into actor-isolated context may introduce data races}}
   // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
-  print(ns0) // expected-tns-note {{access can happen concurrently}}
+  print(ns0) // expected-note {{access can happen concurrently}}
   print(ns1)
   print(ns2)
   print(ns3)
 
   // this should consume ns1 and ns2
   await a.run_closure(captures12)
-  // expected-tns-warning @-1 {{sending 'captures12' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'captures12' to actor-isolated instance method 'run_closure' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'captures12' risks causing data races}}
+  // expected-note @-2 {{sending 'captures12' to actor-isolated instance method 'run_closure' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into actor-isolated context may introduce data races}}
   // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
   // This only touches ns1/ns2 so we get an error on ns1 since it is first.
   print(ns0)
-  print(ns1) // expected-tns-note {{access can happen concurrently}}
+  print(ns1) // expected-note {{access can happen concurrently}}
   print(ns2)
   print(ns3)
 
   // this should consume ns3
   await a.run_closure(captures3indirect)
-  // expected-tns-warning @-1 {{sending 'captures3indirect' risks causing data races}}
-  // expected-tns-note @-2 {{sending 'captures3indirect' to actor-isolated instance method 'run_closure' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending 'captures3indirect' risks causing data races}}
+  // expected-note @-2 {{sending 'captures3indirect' to actor-isolated instance method 'run_closure' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into actor-isolated context may introduce data races}}
   // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
 
   // This only uses ns3 so we should only emit an error on ns3.
   print(ns0)
   print(ns1)
   print(ns2)
-  print(ns3) // expected-tns-note {{access can happen concurrently}}
+  print(ns3) // expected-note {{access can happen concurrently}}
 }
 
 func test_regions(a : A, b : Bool) async {
@@ -161,68 +163,68 @@ func test_regions(a : A, b : Bool) async {
   // check for each of the above pairs that consuming half of it consumes the other half
 
   if (b) {
-    await a.foo(ns0_0) // expected-tns-warning {{sending 'ns0_0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns0_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns0_0) // expected-warning {{sending 'ns0_0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns0_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if (b) {
-      print(ns0_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns0_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns0_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns0_1) // expected-note {{access can happen concurrently}}
     }
   } else {
-    await a.foo(ns0_1) // expected-tns-warning {{sending 'ns0_1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns0_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns0_1) // expected-warning {{sending 'ns0_1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns0_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns0_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns0_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns0_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns0_1) // expected-note {{access can happen concurrently}}
     }
   }
 
   if (b) {
-    await a.foo(ns1_0) // expected-tns-warning {{sending 'ns1_0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns1_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns1_0) // expected-warning {{sending 'ns1_0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns1_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns1_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns1_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns1_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns1_1) // expected-note {{access can happen concurrently}}
     }
   } else {
-    await a.foo(ns1_1) // expected-tns-warning {{sending 'ns1_1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns1_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns1_1) // expected-warning {{sending 'ns1_1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns1_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns1_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns1_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns1_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns1_1) // expected-note {{access can happen concurrently}}
     }
   }
 
   if (b) {
-    await a.foo(ns2_0) // expected-tns-warning {{sending 'ns2_0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns2_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns2_0) // expected-warning {{sending 'ns2_0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns2_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns2_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns2_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns2_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns2_1) // expected-note {{access can happen concurrently}}
     }
   } else {
-    await a.foo(ns2_1) // expected-tns-warning {{sending 'ns2_1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns2_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns2_1) // expected-warning {{sending 'ns2_1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns2_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns2_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns2_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns2_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns2_1) // expected-note {{access can happen concurrently}}
     }
   }
 }
@@ -266,134 +268,134 @@ func test_indirect_regions(a : A, b : Bool) async {
   // now check for each pair that consuming half of it consumed the other half
 
   if (b) {
-    await a.foo(ns0_0) // expected-tns-warning {{sending 'ns0_0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns0_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns0_0) // expected-warning {{sending 'ns0_0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns0_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns0_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns0_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns0_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns0_1) // expected-note {{access can happen concurrently}}
     }
   } else {
-    await a.foo(ns0_1) // expected-tns-warning {{sending 'ns0_1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns0_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns0_1) // expected-warning {{sending 'ns0_1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns0_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns0_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns0_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns0_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns0_1) // expected-note {{access can happen concurrently}}
     }
   }
 
   if (b) {
-    await a.foo(ns1_0) // expected-tns-warning {{sending 'ns1_0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns1_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns1_0) // expected-warning {{sending 'ns1_0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns1_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns1_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns1_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns1_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns1_1) // expected-note {{access can happen concurrently}}
     }
   } else {
-    await a.foo(ns1_1) // expected-tns-warning {{sending 'ns1_1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns1_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns1_1) // expected-warning {{sending 'ns1_1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns1_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns1_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns1_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns1_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns1_1) // expected-note {{access can happen concurrently}}
     }
   }
 
   if (b) {
-    await a.foo(ns2_0) // expected-tns-warning {{sending 'ns2_0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns2_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns2_0) // expected-warning {{sending 'ns2_0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns2_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns2_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns2_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns2_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns2_1) // expected-note {{access can happen concurrently}}
     }
   } else {
-    await a.foo(ns2_1) // expected-tns-warning {{sending 'ns2_1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns2_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns2_1) // expected-warning {{sending 'ns2_1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns2_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns2_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns2_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns2_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns2_1) // expected-note {{access can happen concurrently}}
     }
   }
 
   if (b) {
-    await a.foo(ns3_0) // expected-tns-warning {{sending 'ns3_0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns3_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns3_0) // expected-warning {{sending 'ns3_0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns3_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns3_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns3_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns3_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns3_1) // expected-note {{access can happen concurrently}}
     }
   } else {
-    await a.foo(ns3_1) // expected-tns-warning {{sending 'ns3_1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns3_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns3_1) // expected-warning {{sending 'ns3_1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns3_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns3_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns3_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns3_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns3_1) // expected-note {{access can happen concurrently}}
     }
   }
 
   if (b) {
-    await a.foo(ns4_0) // expected-tns-warning {{sending 'ns4_0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns4_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns4_0) // expected-warning {{sending 'ns4_0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns4_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns4_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns4_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns4_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns4_1) // expected-note {{access can happen concurrently}}
     }
   } else {
-    await a.foo(ns4_1) // expected-tns-warning {{sending 'ns4_1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns4_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns4_1) // expected-warning {{sending 'ns4_1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns4_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns4_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns4_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns4_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns4_1) // expected-note {{access can happen concurrently}}
     }
   }
 
   if (b) {
-    await a.foo(ns5_0) // expected-tns-warning {{sending 'ns5_0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns5_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any' into actor-isolated context may introduce data races}}
+    await a.foo(ns5_0) // expected-warning {{sending 'ns5_0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns5_0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns5_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns5_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns5_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns5_1) // expected-note {{access can happen concurrently}}
     }
   } else {
-    await a.foo(ns5_1) // expected-tns-warning {{sending 'ns5_1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns5_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any' into actor-isolated context may introduce data races}}
+    await a.foo(ns5_1) // expected-warning {{sending 'ns5_1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns5_1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any' into actor-isolated context may introduce data races}}
 
     if b {
-      print(ns5_0) // expected-tns-note {{access can happen concurrently}}
+      print(ns5_0) // expected-note {{access can happen concurrently}}
     } else {
-      print(ns5_1) // expected-tns-note {{access can happen concurrently}}
+      print(ns5_1) // expected-note {{access can happen concurrently}}
     }
   }
 }
@@ -410,9 +412,9 @@ class C_NonSendable {
     foo_noniso(captures_self)
 
     // this is a cross-isolation call that captures non-Sendable self, so it should not be permitted
-    await a.foo(captures_self) // expected-tns-warning {{sending 'captures_self' risks causing data races}}
-    // expected-tns-note @-1 {{sending task-isolated 'captures_self' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and task-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type '() -> ()' into actor-isolated context may introduce data races}}
+    await a.foo(captures_self) // expected-warning {{sending 'captures_self' risks causing data races}}
+    // expected-note @-1 {{sending task-isolated 'captures_self' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and task-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type '() -> ()' into actor-isolated context may introduce data races}}
     // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
   }
 }
@@ -428,7 +430,7 @@ final class C_Sendable : Sendable {
 
     // this is a cross-isolation, but self is Sendable, so it should be permitted
     await a.foo(captures_self)
-    // expected-complete-warning @-1 {{passing argument of non-sendable type '() -> ()' into actor-isolated context may introduce data races}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into actor-isolated context may introduce data races}}
     // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
   }
 }
@@ -447,9 +449,9 @@ actor A_Sendable {
     // actor and is non-Sendable. For now, we ban this since we do not
     // support the ability to dynamically invoke the synchronous closure on
     // the specific actor.
-    await a.foo(captures_self) // expected-tns-warning {{sending 'captures_self' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'self'-isolated 'captures_self' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and 'self'-isolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type '() -> ()' into actor-isolated context may introduce data races}}
+    await a.foo(captures_self) // expected-warning {{sending 'captures_self' risks causing data races}}
+    // expected-note @-1 {{sending 'self'-isolated 'captures_self' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and 'self'-isolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type '() -> ()' into actor-isolated context may introduce data races}}
     // expected-complete-note @-3 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
   }
 }
@@ -458,10 +460,10 @@ func basic_loopiness(a : A, b : Bool) async {
   let ns = NonSendable()
 
   while (b) {
-    await a.foo(ns) // expected-tns-warning {{sending 'ns' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-tns-note @-2 {{access can happen concurrently}}
-    // expected-complete-warning @-3 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns) // expected-warning {{sending 'ns' risks causing data races}}
+    // expected-note @-1 {{sending 'ns' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-note @-2 {{access can happen concurrently}}
+    // expected-complete-warning @-3 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
   }
 }
 
@@ -476,11 +478,11 @@ func basic_loopiness_unsafe(a : A, b : Bool) async {
     (ns0, ns1, ns2, ns3) = (ns1, ns2, ns3, ns0)
   }
 
-  await a.foo(ns0) // expected-tns-warning {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  await a.foo(ns3) // expected-tns-note {{access can happen concurrently}}
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(ns0) // expected-warning {{sending 'ns0' risks causing data races}}
+  // expected-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(ns3) // expected-note {{access can happen concurrently}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 }
 
 func basic_loopiness_safe(a : A, b : Bool) async {
@@ -495,9 +497,9 @@ func basic_loopiness_safe(a : A, b : Bool) async {
   }
 
   await a.foo(ns0)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
   await a.foo(ns3)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 }
 
 struct StructBox {
@@ -518,9 +520,9 @@ func test_struct_assign_doesnt_merge(a : A, b : Bool) async {
   box.contents = ns1
 
   await a.foo(ns0)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
   await a.foo(ns1)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 }
 
 class ClassBox {
@@ -541,11 +543,11 @@ func test_class_assign_merges(a : A, b : Bool) async {
   box.contents = ns0
   box.contents = ns1
 
-  await a.foo(ns0) // expected-tns-warning {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  await a.foo(ns1) // expected-tns-note {{access can happen concurrently}}
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(ns0) // expected-warning {{sending 'ns0' risks causing data races}}
+  // expected-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(ns1) // expected-note {{access can happen concurrently}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 }
 
 func test_stack_assign_doesnt_merge(a : A, b : Bool) async {
@@ -560,9 +562,9 @@ func test_stack_assign_doesnt_merge(a : A, b : Bool) async {
   foo_noniso(contents) //must use var to avoid warning
 
   await a.foo(ns0)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
   await a.foo(ns1)
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 }
 
 func test_stack_assign_and_capture_merges(a : A, b : Bool) async {
@@ -578,11 +580,11 @@ func test_stack_assign_and_capture_merges(a : A, b : Bool) async {
   contents = ns0
   contents = ns1
 
-  await a.foo(ns0) // expected-tns-warning {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  await a.foo(ns1) // expected-tns-note {{access can happen concurrently}}
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(ns0) // expected-warning {{sending 'ns0' risks causing data races}}
+  // expected-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo(ns1) // expected-note {{access can happen concurrently}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 }
 
 func test_tuple_formation(a : A, i : Int) async {
@@ -596,115 +598,115 @@ func test_tuple_formation(a : A, i : Int) async {
 
   switch (i) {
   case 0:
-    await a.foo(ns0) // expected-tns-warning {{sending 'ns0' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns0) // expected-warning {{sending 'ns0' risks causing data races}}
+    // expected-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if bool {
-      foo_noniso(ns0); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns0); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns1); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns1); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns2); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns2); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns3); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns3); // expected-note {{access can happen concurrently}}
     } else if bool {
       foo_noniso(ns4);
     } else if bool {
-      foo_noniso(ns012); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns012); // expected-note {{access can happen concurrently}}
     } else {
-      foo_noniso(ns13); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns13); // expected-note {{access can happen concurrently}}
     }
   case 1:
-    await a.foo(ns1) // expected-tns-warning {{sending 'ns1' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns1) // expected-warning {{sending 'ns1' risks causing data races}}
+    // expected-note @-1 {{sending 'ns1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if bool {
-      foo_noniso(ns0); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns0); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns1); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns1); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns2); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns2); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns3); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns3); // expected-note {{access can happen concurrently}}
     } else if bool {
       foo_noniso(ns4);
     } else if bool {
-      foo_noniso(ns012); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns012); // expected-note {{access can happen concurrently}}
     } else {
-      foo_noniso(ns13); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns13); // expected-note {{access can happen concurrently}}
     }
   case 2:
-    await a.foo(ns2) // expected-tns-warning {{sending 'ns2' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns2' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns2) // expected-warning {{sending 'ns2' risks causing data races}}
+    // expected-note @-1 {{sending 'ns2' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     if bool {
-      foo_noniso(ns0); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns0); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns1); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns1); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns2); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns2); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns3); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns3); // expected-note {{access can happen concurrently}}
     } else if bool {
       foo_noniso(ns4);
     } else if bool {
-      foo_noniso(ns012); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns012); // expected-note {{access can happen concurrently}}
     } else {
-      foo_noniso(ns13); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns13); // expected-note {{access can happen concurrently}}
     }
   case 3:
-    await a.foo(ns4) // expected-tns-warning {{sending 'ns4' risks causing data races}}
-    // expected-tns-note @-1 {{sending 'ns4' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 {{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+    await a.foo(ns4) // expected-warning {{sending 'ns4' risks causing data races}}
+    // expected-note @-1 {{sending 'ns4' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 {{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
     foo_noniso(ns0);
     foo_noniso(ns1);
     foo_noniso(ns2);
-    foo_noniso(ns4); // expected-tns-note {{access can happen concurrently}}
+    foo_noniso(ns4); // expected-note {{access can happen concurrently}}
     foo_noniso(ns012);
     foo_noniso(ns13);
   case 4:
-    await a.foo(ns012) // expected-tns-warning {{sending value of non-Sendable type '(NonSendable, NonSendable, NonSendable)' risks causing data races}}
-    // expected-tns-note @-1 {{sending value of non-Sendable type '(NonSendable, NonSendable, NonSendable)' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-2 3{{passing argument of non-sendable type '(NonSendable, NonSendable, NonSendable)' into actor-isolated context may introduce data races}}
+    await a.foo(ns012) // expected-warning {{sending value of non-Sendable type '(NonSendable, NonSendable, NonSendable)' risks causing data races}}
+    // expected-note @-1 {{sending value of non-Sendable type '(NonSendable, NonSendable, NonSendable)' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-2 3{{passing argument of non-Sendable type '(NonSendable, NonSendable, NonSendable)' into actor-isolated context may introduce data races}}
 
     if bool {
-      foo_noniso(ns0); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns0); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns1); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns1); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns2); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns2); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns3); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns3); // expected-note {{access can happen concurrently}}
     } else if bool {
       foo_noniso(ns4);
     } else if bool {
-      foo_noniso(ns012); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns012); // expected-note {{access can happen concurrently}}
     } else {
-      foo_noniso(ns13); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns13); // expected-note {{access can happen concurrently}}
     }
   default:
-      await a.foo(ns13) // expected-tns-warning {{sending value of non-Sendable type '(NonSendable, NonSendable)' risks causing data races}}
-      // expected-tns-note @-1 {{sending value of non-Sendable type '(NonSendable, NonSendable)' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-    // expected-complete-warning @-1 2{{passing argument of non-sendable type '(NonSendable, NonSendable)' into actor-isolated context may introduce data races}}
+      await a.foo(ns13) // expected-warning {{sending value of non-Sendable type '(NonSendable, NonSendable)' risks causing data races}}
+      // expected-note @-1 {{sending value of non-Sendable type '(NonSendable, NonSendable)' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+    // expected-complete-warning @-1 2{{passing argument of non-Sendable type '(NonSendable, NonSendable)' into actor-isolated context may introduce data races}}
 
     if bool {
-      foo_noniso(ns0); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns0); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns1); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns1); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns2); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns2); // expected-note {{access can happen concurrently}}
     } else if bool {
-      foo_noniso(ns3); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns3); // expected-note {{access can happen concurrently}}
     } else if bool {
       foo_noniso(ns4);
     } else if bool {
-      foo_noniso(ns012); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns012); // expected-note {{access can happen concurrently}}
     } else  {
-      foo_noniso(ns13); // expected-tns-note {{access can happen concurrently}}
+      foo_noniso(ns13); // expected-note {{access can happen concurrently}}
     }
   }
 }
@@ -716,9 +718,9 @@ func reuse_args_safe(a : A) async {
 
   // this should be perfectly legal - arguments are assumed to come from the same region
   await a.foo_multi(ns0, ns0, ns0);
-  // expected-complete-warning @-1 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
   await a.foo_multi(ns1, ns2, ns1);
-  // expected-complete-warning @-1 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 }
 
 func one_consume_many_require(a : A) async {
@@ -729,17 +731,17 @@ func one_consume_many_require(a : A) async {
   let ns4 = NonSendable();
 
   await a.foo_multi(ns0, ns1, ns2);
-  // expected-complete-warning @-1 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  // expected-tns-warning @-2 {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-3 {{sending 'ns0' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-tns-warning @-4 {{sending 'ns1' risks causing data races}}
-  // expected-tns-note @-5 {{sending 'ns1' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-tns-warning @-6 {{sending 'ns2' risks causing data races}}
-  // expected-tns-note @-7 {{sending 'ns2' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-1 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-warning @-2 {{sending 'ns0' risks causing data races}}
+  // expected-note @-3 {{sending 'ns0' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-warning @-4 {{sending 'ns1' risks causing data races}}
+  // expected-note @-5 {{sending 'ns1' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-warning @-6 {{sending 'ns2' risks causing data races}}
+  // expected-note @-7 {{sending 'ns2' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
 
-  foo_noniso_multi(ns0, ns3, ns4); // expected-tns-note {{access can happen concurrently}}
-  foo_noniso_multi(ns3, ns1, ns4); // expected-tns-note {{access can happen concurrently}}
-  foo_noniso_multi(ns4, ns3, ns2); // expected-tns-note {{access can happen concurrently}}
+  foo_noniso_multi(ns0, ns3, ns4); // expected-note {{access can happen concurrently}}
+  foo_noniso_multi(ns3, ns1, ns4); // expected-note {{access can happen concurrently}}
+  foo_noniso_multi(ns4, ns3, ns2); // expected-note {{access can happen concurrently}}
 }
 
 func one_consume_one_require(a : A) async {
@@ -748,15 +750,15 @@ func one_consume_one_require(a : A) async {
   let ns2 = NonSendable();
 
   await a.foo_multi(ns0, ns1, ns2);
-  // expected-complete-warning @-1 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  // expected-tns-warning @-2 {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-3 {{sending 'ns0' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-tns-warning @-4 {{sending 'ns1' risks causing data races}}
-  // expected-tns-note @-5 {{sending 'ns1' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-tns-warning @-6 {{sending 'ns2' risks causing data races}}
-  // expected-tns-note @-7 {{sending 'ns2' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-1 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  // expected-warning @-2 {{sending 'ns0' risks causing data races}}
+  // expected-note @-3 {{sending 'ns0' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-warning @-4 {{sending 'ns1' risks causing data races}}
+  // expected-note @-5 {{sending 'ns1' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-warning @-6 {{sending 'ns2' risks causing data races}}
+  // expected-note @-7 {{sending 'ns2' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
 
-  foo_noniso_multi(ns0, ns1, ns2); // expected-tns-note 3{{access can happen concurrently}}
+  foo_noniso_multi(ns0, ns1, ns2); // expected-note 3{{access can happen concurrently}}
 }
 
 func many_consume_one_require(a : A) async {
@@ -767,16 +769,16 @@ func many_consume_one_require(a : A) async {
   let ns4 = NonSendable();
   let ns5 = NonSendable();
 
-  await a.foo_multi(ns0, ns3, ns3) // expected-tns-warning {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  await a.foo_multi(ns4, ns1, ns4) // expected-tns-warning {{sending 'ns1' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns1' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  await a.foo_multi(ns5, ns5, ns2) // expected-tns-warning {{sending 'ns2' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns2' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  foo_noniso_multi(ns0, ns1, ns2); //expected-tns-note 3{{access can happen concurrently}}
+  await a.foo_multi(ns0, ns3, ns3) // expected-warning {{sending 'ns0' risks causing data races}}
+  // expected-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo_multi(ns4, ns1, ns4) // expected-warning {{sending 'ns1' risks causing data races}}
+  // expected-note @-1 {{sending 'ns1' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo_multi(ns5, ns5, ns2) // expected-warning {{sending 'ns2' risks causing data races}}
+  // expected-note @-1 {{sending 'ns2' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  foo_noniso_multi(ns0, ns1, ns2); //expected-note 3{{access can happen concurrently}}
 }
 
 func many_consume_many_require(a : A) async {
@@ -789,19 +791,19 @@ func many_consume_many_require(a : A) async {
   let ns6 = NonSendable();
   let ns7 = NonSendable();
 
-  await a.foo_multi(ns0, ns3, ns3) // expected-tns-warning {{sending 'ns0' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  await a.foo_multi(ns4, ns1, ns4) // expected-tns-warning {{sending 'ns1' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns1' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
-  await a.foo_multi(ns5, ns5, ns2) // expected-tns-warning {{sending 'ns2' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'ns2' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 3{{passing argument of non-sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo_multi(ns0, ns3, ns3) // expected-warning {{sending 'ns0' risks causing data races}}
+  // expected-note @-1 {{sending 'ns0' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo_multi(ns4, ns1, ns4) // expected-warning {{sending 'ns1' risks causing data races}}
+  // expected-note @-1 {{sending 'ns1' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
+  await a.foo_multi(ns5, ns5, ns2) // expected-warning {{sending 'ns2' risks causing data races}}
+  // expected-note @-1 {{sending 'ns2' to actor-isolated instance method 'foo_multi' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 3{{passing argument of non-Sendable type 'NonSendable' into actor-isolated context may introduce data races}}
 
-  foo_noniso_multi(ns0, ns6, ns7); // expected-tns-note {{access can happen concurrently}}
-  foo_noniso_multi(ns6, ns1, ns7); // expected-tns-note {{access can happen concurrently}}
-  foo_noniso_multi(ns7, ns6, ns2); // expected-tns-note {{access can happen concurrently}}
+  foo_noniso_multi(ns0, ns6, ns7); // expected-note {{access can happen concurrently}}
+  foo_noniso_multi(ns6, ns1, ns7); // expected-note {{access can happen concurrently}}
+  foo_noniso_multi(ns7, ns6, ns2); // expected-note {{access can happen concurrently}}
 }
 
 
@@ -812,9 +814,9 @@ func reuse_args_safe_vararg(a : A) async {
 
   // this should be perfectly legal - arguments are assumed to come from the same region
   await a.foo_vararg(ns0, ns0, ns0);
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
   await a.foo_vararg(ns1, ns2, ns1);
-  // expected-complete-warning @-1 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
 }
 
 func one_consume_many_require_varag(a : A) async {
@@ -826,16 +828,16 @@ func one_consume_many_require_varag(a : A) async {
 
   // TODO: find a way to make the type used in the diagnostic more specific than the signature type
   await a.foo_vararg(ns0, ns1, ns2);
-  // expected-tns-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
-  // expected-tns-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
+  // expected-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
 
   if bool {
-    foo_noniso_vararg(ns0, ns3, ns4); // expected-tns-note {{access can happen concurrently}}
+    foo_noniso_vararg(ns0, ns3, ns4); // expected-note {{access can happen concurrently}}
   } else if bool {
-    foo_noniso_vararg(ns3, ns1, ns4); // expected-tns-note {{access can happen concurrently}}
+    foo_noniso_vararg(ns3, ns1, ns4); // expected-note {{access can happen concurrently}}
   } else {
-    foo_noniso_vararg(ns4, ns3, ns2); // expected-tns-note {{access can happen concurrently}}
+    foo_noniso_vararg(ns4, ns3, ns2); // expected-note {{access can happen concurrently}}
   }
 }
 
@@ -845,11 +847,11 @@ func one_consume_one_require_vararg(a : A) async {
   let ns2 = NonSendable();
 
   await a.foo_vararg(ns0, ns1, ns2);
-  // expected-tns-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
-  // expected-tns-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
+  // expected-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
 
-  foo_noniso_vararg(ns0, ns1, ns2); // expected-tns-note 1{{access can happen concurrently}}
+  foo_noniso_vararg(ns0, ns1, ns2); // expected-note 1{{access can happen concurrently}}
 }
 
 func many_consume_one_require_vararg(a : A) async {
@@ -861,19 +863,19 @@ func many_consume_one_require_vararg(a : A) async {
   let ns5 = NonSendable();
 
   await a.foo_vararg(ns0, ns3, ns3)
-  // expected-tns-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
-  // expected-tns-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
+  // expected-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
   await a.foo_vararg(ns4, ns1, ns4)
-  // expected-tns-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
-  // expected-tns-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
+  // expected-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
   await a.foo_vararg(ns5, ns5, ns2)
-  // expected-tns-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
-  // expected-tns-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
+  // expected-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
 
-  foo_noniso_vararg(ns0, ns1, ns2); // expected-tns-note 3{{access can happen concurrently}}
+  foo_noniso_vararg(ns0, ns1, ns2); // expected-note 3{{access can happen concurrently}}
 }
 
 func many_consume_many_require_vararg(a : A) async {
@@ -887,24 +889,24 @@ func many_consume_many_require_vararg(a : A) async {
   let ns7 = NonSendable();
 
   await a.foo_vararg(ns0, ns3, ns3)
-  // expected-tns-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
-  // expected-tns-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
+  // expected-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
   await a.foo_vararg(ns4, ns1, ns4)
-  // expected-tns-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
-  // expected-tns-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
+  // expected-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
   await a.foo_vararg(ns5, ns5, ns2)
-  // expected-tns-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
-  // expected-tns-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'Any...' into actor-isolated context may introduce data races}}
+  // expected-warning @-1 {{sending value of non-Sendable type 'Any...' risks causing data races}}
+  // expected-note @-2 {{sending value of non-Sendable type 'Any...' to actor-isolated instance method 'foo_vararg' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'Any...' into actor-isolated context may introduce data races}}
 
   if bool {
-    foo_noniso_vararg(ns0, ns6, ns7); // expected-tns-note {{access can happen concurrently}}
+    foo_noniso_vararg(ns0, ns6, ns7); // expected-note {{access can happen concurrently}}
   } else if bool {
-    foo_noniso_vararg(ns6, ns1, ns7);  // expected-tns-note {{access can happen concurrently}}
+    foo_noniso_vararg(ns6, ns1, ns7);  // expected-note {{access can happen concurrently}}
   } else {
-    foo_noniso_vararg(ns7, ns6, ns2);  // expected-tns-note {{access can happen concurrently}}
+    foo_noniso_vararg(ns7, ns6, ns2);  // expected-note {{access can happen concurrently}}
   }
 }
 
@@ -934,9 +936,9 @@ func enum_test(a : A) async {
     case .E2:
       switch (e3) {
       case let .E3(ns3):
-        await a.foo(ns3.x) // expected-tns-warning {{sending value of non-Sendable type 'Any' risks causing data races}}
-        // expected-tns-note @-1 {{sending value of non-Sendable type 'Any' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-        // expected-complete-warning @-1 {{passing argument of non-sendable type 'Any' into actor-isolated context may introduce data races}}
+        await a.foo(ns3.x) // expected-warning {{sending value of non-Sendable type 'Any' risks causing data races}}
+        // expected-note @-1 {{sending value of non-Sendable type 'Any' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+        // expected-complete-warning @-1 {{passing argument of non-Sendable type 'Any' into actor-isolated context may introduce data races}}
       default: ()
       }
 
@@ -945,10 +947,10 @@ func enum_test(a : A) async {
         foo_noniso(e4);
   }
 
-  await a.foo(e1); // expected-tns-warning {{sending 'e1' risks causing data races}}
-  // expected-tns-note @-1 {{sending 'e1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
-  // expected-complete-warning @-2 {{passing argument of non-sendable type 'E' into actor-isolated context may introduce data races}}
-  foo_noniso(e2); // expected-tns-note {{access can happen concurrently}}
-  foo_noniso(e3); // expected-tns-note {{access can happen concurrently}}
+  await a.foo(e1); // expected-warning {{sending 'e1' risks causing data races}}
+  // expected-note @-1 {{sending 'e1' to actor-isolated instance method 'foo' risks causing data races between actor-isolated and local nonisolated uses}}
+  // expected-complete-warning @-2 {{passing argument of non-Sendable type 'E' into actor-isolated context may introduce data races}}
+  foo_noniso(e2); // expected-note {{access can happen concurrently}}
+  foo_noniso(e3); // expected-note {{access can happen concurrently}}
   foo_noniso(e4);
 }
diff --git a/test/Concurrency/transfernonsendable_sending_params.swift b/test/Concurrency/transfernonsendable_sending_params.swift
index e71857f4f2a87..f8024bc575571 100644
--- a/test/Concurrency/transfernonsendable_sending_params.swift
+++ b/test/Concurrency/transfernonsendable_sending_params.swift
@@ -1,7 +1,9 @@
-// RUN: %target-swift-frontend -emit-sil -parse-as-library -target %target-swift-5.1-abi-triple -strict-concurrency=complete -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -target %target-swift-5.1-abi-triple -strict-concurrency=complete -verify -verify-additional-prefix ni- %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -target %target-swift-5.1-abi-triple -strict-concurrency=complete -verify -verify-additional-prefix ni-ns- %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
@@ -37,6 +39,8 @@ final class FinalKlassWithNonSendableStructPair {
 }
 
 func useValue<T>(_ t: T) {}
+func useValueAndReturnGeneric<T>(_ t: T) -> T { t }
+func useNonSendableKlassAndReturn(_ t: NonSendableKlass) -> NonSendableKlass { t }
 func getAny() -> Any { fatalError() }
 
 actor Custom {
@@ -54,6 +58,8 @@ struct CustomActor {
 
 func throwingFunction() throws { fatalError() }
 
+func getBool() -> Bool { false }
+
 func transferArg(_ x: sending NonSendableKlass) {
 }
 
@@ -109,7 +115,6 @@ func testSimpleTransferUseOfOtherParamNoError2() {
 }
 
 @MainActor func transferToMain2(_ x: sending NonSendableKlass, _ y: NonSendableKlass, _ z: NonSendableKlass) async {
-
 }
 
 // TODO: How to test this?
@@ -387,9 +392,9 @@ func taskIsolatedInsideError(_ x: @escaping @MainActor () async -> ()) {
 @MainActor func actorIsolatedInsideError(_ x: @escaping @MainActor () async -> ()) {
   func fakeInit(operation: sending @escaping () async -> ()) {}
 
-  // We do not get an error here since fakeInit is main actor isolated since it
+  // We do not get an error here since fakeInit is MainActor isolated since it
   // is defined within this function. As a result, we are sending a @MainActor
-  // isolated thing to a MainActor isolated thing.
+  // isolated thing to a MainActor-isolated thing.
   fakeInit(operation: x)
 }
 
@@ -439,7 +444,7 @@ func testNoCrashWhenSendingNoEscapeClosure() async {
 func testInOutSendingReinit(_ x: inout sending NonSendableKlass) async {
   await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
   // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-} // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor isolated value}}
+} // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
 
 func testInOutSendingReinit2(_ x: inout sending NonSendableKlass) async {
   await transferToMain(x)
@@ -450,7 +455,7 @@ func testInOutSendingReinit3(_ x: inout sending NonSendableKlass) async throws {
   await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
   // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
 
-  try throwingFunction() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor isolated value}}
+  try throwingFunction() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
 
   x = NonSendableKlass()
 }
@@ -463,7 +468,7 @@ func testInOutSendingReinit4(_ x: inout sending NonSendableKlass) async throws {
     try throwingFunction()
     x = NonSendableKlass()
   } catch {
-    throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor isolated value}}
+    throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
   }
 
   x = NonSendableKlass()
@@ -476,7 +481,7 @@ func testInOutSendingReinit5(_ x: inout sending NonSendableKlass) async throws {
   do {
     try throwingFunction()
   } catch {
-    throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor isolated value}}
+    throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
   }
 
   x = NonSendableKlass()
@@ -489,9 +494,9 @@ func testInOutSendingReinit6(_ x: inout sending NonSendableKlass) async throws {
   do {
     try throwingFunction()
   } catch {
-    throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor isolated value}}
+    throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
   }
-} // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor isolated value}}
+} // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
 
 actor InOutSendingWrongIsolationActor {
   var ns = NonSendableKlass()
@@ -513,6 +518,2422 @@ func testWrongIsolationGlobalIsolation(_ x: inout sending NonSendableKlass) {
 } // expected-warning {{'inout sending' parameter 'x' cannot be main actor-isolated at end of function}}
 // expected-note @-1 {{main actor-isolated 'x' risks causing races in between main actor-isolated uses and caller uses since caller assumes value is not actor isolated}}
 
+//////////////////////////////////////
+// MARK: Return Inout Sending Tests //
+//////////////////////////////////////
+
+func returnInOutSendingDirectly(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingRegionLet(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingRegionVar(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+
+func returnInOutSendingViaHelper(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingHelperDirect(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingDirectlyIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  if getBool() {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  fatalError()
+}
+
+func returnInOutSendingRegionLetIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  } else {
+    print(y)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingRegionVarIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  if getBool() {
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  fatalError()
+}
+
+func returnInOutSendingViaHelperIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  if getBool() {
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  } else {
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingHelperDirectIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  if getBool() {
+    return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  } else {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingViaHelperVarIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  if getBool() {
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  } else {
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingDirectlyElse(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  if getBool() {
+    print(x)
+    fatalError()
+  } else {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingRegionLetElse(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  if getBool() {
+    print(y)
+    fatalError()
+  } else {
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingRegionVarElse(_ x: inout sending NonSendableKlass, z: NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  if getBool() {
+    print(y)
+    return z
+  } else {
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingViaHelperElse(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  if getBool() {
+    print(y)
+    return z
+  } else {
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingHelperDirectElse(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+  if getBool() {
+    print(x)
+    return z
+  } else {
+    return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingViaHelperVarElse(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  if getBool() {
+    print(y)
+    return z
+  } else {
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnInOutSendingDirectlyFor(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+  for _ in 0..<1 {
+    if getBool() {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(x)
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingDirectlyFor2(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+  for _ in 0..<1 {
+    if getBool() {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(x)
+  return z
+}
+
+func returnInOutSendingRegionLetFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingRegionLetFor2(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingRegionLetFor3(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return z
+}
+
+func returnInOutSendingRegionVarFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingRegionVarFor2(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingRegionVarFor3(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return z
+}
+
+func returnInOutSendingViaHelperFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(y)
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingViaHelperFor2(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(y)
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingHelperDirectFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  for _ in 0..<1 {
+    if getBool() {
+      return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingViaHelperVarFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(y)
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingDirectlyGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  guard getBool() else {
+    print(x)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingRegionLetGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  guard getBool() else {
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingRegionVarGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  guard getBool() else {
+    print(y)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingViaHelperGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  let y = x
+  guard getBool() else {
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingHelperDirectGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  guard getBool() else {
+    print(x)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingViaHelperVarGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  guard getBool() else {
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnInOutSendingViaHelperVar(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+  var y = x
+  y = x
+  return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingDirectly<T>(_ x: inout sending T) -> T {
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingRegionLet<T>(_ x: inout sending T) -> T {
+  let y = x
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingRegionVar<T>(_ x: inout sending T) -> T {
+  var y = x
+  y = x
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingViaHelper<T>(_ x: inout sending T) -> T {
+  let y = x
+  return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingHelperDirect<T>(_ x: inout sending T) -> T {
+  return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingViaHelperVar<T>(_ x: inout sending T) -> T {
+  var y = x
+  y = x
+  return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingDirectlyIf<T>(_ x: inout sending T) -> T {
+  if getBool() {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  fatalError()
+}
+
+func returnGenericInOutSendingRegionLetIf<T>(_ x: inout sending T) -> T {
+  let y = x
+  if getBool() {
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  } else {
+    print(y)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingRegionVarIf<T>(_ x: inout sending T) -> T {
+  var y = x
+  y = x
+  if getBool() {
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  fatalError()
+}
+
+func returnGenericInOutSendingViaHelperIf<T>(_ x: inout sending T) -> T {
+  let y = x
+  if getBool() {
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  } else {
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingHelperDirectIf<T>(_ x: inout sending T) -> T {
+  if getBool() {
+    return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  } else {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingViaHelperVarIf<T>(_ x: inout sending T) -> T {
+  var y = x
+  y = x
+  if getBool() {
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  } else {
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingDirectlyElse<T>(_ x: inout sending T) -> T {
+  if getBool() {
+    print(x)
+    fatalError()
+  } else {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingRegionLetElse<T>(_ x: inout sending T) -> T {
+  let y = x
+  if getBool() {
+    print(y)
+    fatalError()
+  } else {
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingRegionVarElse<T>(_ x: inout sending T, z: T) -> T {
+  var y = x
+  y = x
+  if getBool() {
+    print(y)
+    return z
+  } else {
+      return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingViaHelperElse<T>(_ x: inout sending T, _ z: T) -> T {
+  let y = x
+  if getBool() {
+    print(y)
+    return z
+  } else {
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingHelperDirectElse<T>(_ x: inout sending T, _ z: T) -> T {
+  if getBool() {
+    print(x)
+    return z
+  } else {
+    return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingViaHelperVarElse<T>(_ x: inout sending T, _ z: T) -> T {
+  var y = x
+  y = x
+  if getBool() {
+    print(y)
+    return z
+  } else {
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+}
+
+func returnGenericInOutSendingDirectlyFor<T>(_ x: inout sending T, _ z: T) -> T {
+  for _ in 0..<1 {
+    if getBool() {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(x)
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingDirectlyFor2<T>(_ x: inout sending T, _ z: T) -> T {
+  for _ in 0..<1 {
+    if getBool() {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(x)
+  return z
+}
+
+func returnGenericInOutSendingRegionLetFor<T>(_ x: inout sending T) -> T {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingRegionLetFor2<T>(_ x: inout sending T) -> T {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingRegionLetFor3<T>(_ x: inout sending T, _ z: T) -> T {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return z
+}
+
+func returnGenericInOutSendingRegionVarFor<T>(_ x: inout sending T) -> T {
+  var y = x
+  y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingRegionVarFor2<T>(_ x: inout sending T) -> T {
+  var y = x
+  y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingRegionVarFor3<T>(_ x: inout sending T, _ z: T) -> T {
+  var y = x
+  y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return z
+}
+
+func returnGenericInOutSendingViaHelperFor<T>(_ x: inout sending T) -> T {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(y)
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingViaHelperFor2<T>(_ x: inout sending T) -> T {
+  let y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(y)
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingHelperDirectFor<T>(_ x: inout sending T) -> T {
+  for _ in 0..<1 {
+    if getBool() {
+      return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingViaHelperVarFor<T>(_ x: inout sending T) -> T {
+  var y = x
+  y = x
+  for _ in 0..<1 {
+    if getBool() {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+    }
+  }
+  print(y)
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingDirectlyGuard<T>(_ x: inout sending T) -> T {
+  guard getBool() else {
+    print(x)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+  // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingRegionLetGuard<T>(_ x: inout sending T) -> T {
+  let y = x
+  guard getBool() else {
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingRegionVarGuard<T>(_ x: inout sending T) -> T {
+  var y = x
+  y = x
+  guard getBool() else {
+    print(y)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return y // expected-warning {{'y' cannot be returned}}
+  // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingViaHelperGuard<T>(_ x: inout sending T) -> T {
+  let y = x
+  guard getBool() else {
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingHelperDirectGuard<T>(_ x: inout sending T) -> T {
+  guard getBool() else {
+    print(x)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'inout sending' parameter 'x' risks concurrent access as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+func returnGenericInOutSendingViaHelperVarGuard<T>(_ x: inout sending T) -> T {
+  var y = x
+  y = x
+  guard getBool() else {
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+  }
+  return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+  // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' and result can be sent to different isolation domains}}
+}
+
+///////////////////////////////////////////////////
+// MARK: ReturnSendingInOutTestActor Actor Tests //
+///////////////////////////////////////////////////
+
+actor ReturnSendingInOutTestActor {
+
+  func testInOutSendingReinit(_ x: inout sending NonSendableKlass) async {
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local actor-isolated uses}}
+  } // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+
+  func testInOutSendingReinit2(_ x: inout sending NonSendableKlass) async {
+    await transferToMain(x)
+    x = NonSendableKlass()
+  }
+
+  func testInOutSendingReinit3(_ x: inout sending NonSendableKlass) async throws {
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local actor-isolated uses}}
+
+
+    try throwingFunction() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+
+    x = NonSendableKlass()
+  }
+
+  func testInOutSendingReinit4(_ x: inout sending NonSendableKlass) async throws {
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local actor-isolated uses}}
+
+
+    do {
+      try throwingFunction()
+      x = NonSendableKlass()
+    } catch {
+      throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+    }
+
+    x = NonSendableKlass()
+  }
+
+  func testInOutSendingReinit5(_ x: inout sending NonSendableKlass) async throws {
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local actor-isolated uses}}
+
+
+    do {
+      try throwingFunction()
+    } catch {
+      throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+    }
+
+    x = NonSendableKlass()
+  }
+
+  func testInOutSendingReinit6(_ x: inout sending NonSendableKlass) async throws {
+    await transferToMain(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local actor-isolated uses}}
+
+
+    do {
+      try throwingFunction()
+    } catch {
+      throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+    }
+  } // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+
+  func returnInOutSendingDirectly(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingRegionLet(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingRegionVar(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingViaHelper(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingHelperDirect(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingDirectlyIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    if getBool() {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    fatalError()
+  }
+
+  func returnInOutSendingRegionLetIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    } else {
+      print(y)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingRegionVarIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    fatalError()
+  }
+
+  func returnInOutSendingViaHelperIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    if getBool() {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingHelperDirectIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    if getBool() {
+      return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    } else {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingViaHelperVarIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    if getBool() {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    } else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingDirectlyElse(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    if getBool() {
+      print(x)
+      fatalError()
+    } else {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingRegionLetElse(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    if getBool() {
+      print(y)
+      fatalError()
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingRegionVarElse(_ x: inout sending NonSendableKlass, z: NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingViaHelperElse(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingHelperDirectElse(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    if getBool() {
+      print(x)
+      return z
+    } else {
+      return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingViaHelperVarElse(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnInOutSendingDirectlyFor(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    for _ in 0..<1 {
+      if getBool() {
+        return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+        // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(x)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingDirectlyFor2(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    for _ in 0..<1 {
+      if getBool() {
+        return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+        // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(x)
+    return z
+  }
+
+  func returnInOutSendingRegionLetFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingRegionLetFor2(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingRegionLetFor3(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return z
+  }
+
+  func returnInOutSendingRegionVarFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingRegionVarFor2(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingRegionVarFor3(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return z
+  }
+
+  func returnInOutSendingViaHelperFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(y)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingViaHelperFor2(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingHelperDirectFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    for _ in 0..<1 {
+      if getBool() {
+        return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingViaHelperVarFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingDirectlyGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    guard getBool() else {
+      print(x)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingRegionLetGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingRegionVarGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    guard getBool() else {
+      print(y)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingViaHelperGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingHelperDirectGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    guard getBool() else {
+      print(x)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingViaHelperVarGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnInOutSendingViaHelperVar(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingDirectly<T>(_ x: inout sending T) -> T {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionLet<T>(_ x: inout sending T) -> T {
+    let y = x
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionVar<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelper<T>(_ x: inout sending T) -> T {
+    let y = x
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingHelperDirect<T>(_ x: inout sending T) -> T {
+    return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperVar<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingDirectlyIf<T>(_ x: inout sending T) -> T {
+    if getBool() {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    fatalError()
+  }
+
+  func returnGenericInOutSendingRegionLetIf<T>(_ x: inout sending T) -> T {
+    let y = x
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    } else {
+      print(y)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingRegionVarIf<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    fatalError()
+  }
+
+  func returnGenericInOutSendingViaHelperIf<T>(_ x: inout sending T) -> T {
+    let y = x
+    if getBool() {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingHelperDirectIf<T>(_ x: inout sending T) -> T {
+    if getBool() {
+      return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    } else {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingViaHelperVarIf<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    if getBool() {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    } else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingDirectlyElse<T>(_ x: inout sending T) -> T {
+    if getBool() {
+      print(x)
+      fatalError()
+    } else {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingRegionLetElse<T>(_ x: inout sending T) -> T {
+    let y = x
+    if getBool() {
+      print(y)
+      fatalError()
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingRegionVarElse<T>(_ x: inout sending T, z: T) -> T {
+    var y = x
+    y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingViaHelperElse<T>(_ x: inout sending T, _ z: T) -> T {
+    let y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingHelperDirectElse<T>(_ x: inout sending T, _ z: T) -> T {
+    if getBool() {
+      print(x)
+      return z
+    } else {
+      return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingViaHelperVarElse<T>(_ x: inout sending T, _ z: T) -> T {
+    var y = x
+    y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingDirectlyFor<T>(_ x: inout sending T, _ z: T) -> T {
+    for _ in 0..<1 {
+      if getBool() {
+        return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+        // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(x)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingDirectlyFor2<T>(_ x: inout sending T, _ z: T) -> T {
+    for _ in 0..<1 {
+      if getBool() {
+        return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+        // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(x)
+    return z
+  }
+
+  func returnGenericInOutSendingRegionLetFor<T>(_ x: inout sending T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionLetFor2<T>(_ x: inout sending T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionLetFor3<T>(_ x: inout sending T, _ z: T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return z
+  }
+
+  func returnGenericInOutSendingRegionVarFor<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionVarFor2<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionVarFor3<T>(_ x: inout sending T, _ z: T) -> T {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return z
+  }
+
+  func returnGenericInOutSendingViaHelperFor<T>(_ x: inout sending T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(y)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperFor2<T>(_ x: inout sending T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingHelperDirectFor<T>(_ x: inout sending T) -> T {
+    for _ in 0..<1 {
+      if getBool() {
+        return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperVarFor<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+      }
+    }
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingDirectlyGuard<T>(_ x: inout sending T) -> T {
+    guard getBool() else {
+      print(x)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionLetGuard<T>(_ x: inout sending T) -> T {
+    let y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionVarGuard<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    guard getBool() else {
+      print(y)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperGuard<T>(_ x: inout sending T) -> T {
+    let y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingHelperDirectGuard<T>(_ x: inout sending T) -> T {
+    guard getBool() else {
+      print(x)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperVarGuard<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+    }
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is 'self'-isolated}}
+  }
+}
+
+////////////////////////////////////////////////////////////////
+// MARK: ReturnSendingInOutTestGlobalActorIsolatedClass Tests //
+////////////////////////////////////////////////////////////////
+
+@MainActor
+class ReturnSendingInOutTestGlobalActorIsolatedClass {
+
+  func testInOutSendingReinit(_ x: inout sending NonSendableKlass) async {
+    await transferToCustom(x) // expected-warning {{sending 'x' risks causing data races}}
+  } // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+    // expected-note @-2 {{sending 'x' to global actor 'CustomActor'-isolated global function 'transferToCustom' risks causing data races between global actor 'CustomActor'-isolated and local main actor-isolated uses}}
+
+  func testInOutSendingReinit2(_ x: inout sending NonSendableKlass) async {
+    await transferToCustom(x)
+    x = NonSendableKlass()
+  }
+
+  func testInOutSendingReinit3(_ x: inout sending NonSendableKlass) async throws {
+    await transferToCustom(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to global actor 'CustomActor'-isolated global function 'transferToCustom' risks causing data races between global actor 'CustomActor'-isolated and local main actor-isolated uses}}
+
+    try throwingFunction() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+
+    x = NonSendableKlass()
+  }
+
+  func testInOutSendingReinit4(_ x: inout sending NonSendableKlass) async throws {
+    await transferToCustom(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to global actor 'CustomActor'-isolated global function 'transferToCustom' risks causing data races between global actor 'CustomActor'-isolated and local main actor-isolated uses}}
+
+    do {
+      try throwingFunction()
+      x = NonSendableKlass()
+    } catch {
+      throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+    }
+
+    x = NonSendableKlass()
+  }
+
+  func testInOutSendingReinit5(_ x: inout sending NonSendableKlass) async throws {
+    await transferToCustom(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to global actor 'CustomActor'-isolated global function 'transferToCustom' risks causing data races between global actor 'CustomActor'-isolated and local main actor-isolated uses}}
+
+    do {
+      try throwingFunction()
+    } catch {
+      throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+    }
+
+    x = NonSendableKlass()
+  }
+
+  func testInOutSendingReinit6(_ x: inout sending NonSendableKlass) async throws {
+    await transferToCustom(x) // expected-warning {{sending 'x' risks causing data races}}
+    // expected-note @-1 {{sending 'x' to global actor 'CustomActor'-isolated global function 'transferToCustom' risks causing data races between global actor 'CustomActor'-isolated and local main actor-isolated uses}}
+
+    do {
+      try throwingFunction()
+    } catch {
+      throw MyError() // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+    }
+  } // expected-note {{'inout sending' parameter must be reinitialized before function exit with a non-actor-isolated value}}
+
+  func returnInOutSendingDirectly(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingRegionLet(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingRegionVar(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingViaHelper(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingHelperDirect(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingDirectlyIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    if getBool() {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    fatalError()
+  }
+
+  func returnInOutSendingRegionLetIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    } else {
+      print(y)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingRegionVarIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    fatalError()
+  }
+
+  func returnInOutSendingViaHelperIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    if getBool() {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingHelperDirectIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    if getBool() {
+      return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    } else {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingViaHelperVarIf(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    if getBool() {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    } else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingDirectlyElse(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    if getBool() {
+      print(x)
+      fatalError()
+    } else {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingRegionLetElse(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    if getBool() {
+      print(y)
+      fatalError()
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingRegionVarElse(_ x: inout sending NonSendableKlass, z: NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingViaHelperElse(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingHelperDirectElse(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    if getBool() {
+      print(x)
+      return z
+    } else {
+      return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingViaHelperVarElse(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnInOutSendingDirectlyFor(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    for _ in 0..<1 {
+      if getBool() {
+        return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+        // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(x)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingDirectlyFor2(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    for _ in 0..<1 {
+      if getBool() {
+        return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+        // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(x)
+    return z
+  }
+
+  func returnInOutSendingRegionLetFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingRegionLetFor2(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingRegionLetFor3(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return z
+  }
+
+  func returnInOutSendingRegionVarFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingRegionVarFor2(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingRegionVarFor3(_ x: inout sending NonSendableKlass, _ z: NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return z
+  }
+
+  func returnInOutSendingViaHelperFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(y)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingViaHelperFor2(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingHelperDirectFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    for _ in 0..<1 {
+      if getBool() {
+        return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingViaHelperVarFor(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingDirectlyGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    guard getBool() else {
+      print(x)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingRegionLetGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingRegionVarGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    guard getBool() else {
+      print(y)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingViaHelperGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    let y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingHelperDirectGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    guard getBool() else {
+      print(x)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return useNonSendableKlassAndReturn(x) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingViaHelperVarGuard(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnInOutSendingViaHelperVar(_ x: inout sending NonSendableKlass) -> NonSendableKlass {
+    var y = x
+    y = x
+    return useNonSendableKlassAndReturn(y) // expected-warning {{result of global function 'useNonSendableKlassAndReturn' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useNonSendableKlassAndReturn' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingDirectly<T>(_ x: inout sending T) -> T {
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionLet<T>(_ x: inout sending T) -> T {
+    let y = x
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionVar<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelper<T>(_ x: inout sending T) -> T {
+    let y = x
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingHelperDirect<T>(_ x: inout sending T) -> T {
+    return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperVar<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingDirectlyIf<T>(_ x: inout sending T) -> T {
+    if getBool() {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    fatalError()
+  }
+
+  func returnGenericInOutSendingRegionLetIf<T>(_ x: inout sending T) -> T {
+    let y = x
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    } else {
+      print(y)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingRegionVarIf<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    if getBool() {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    fatalError()
+  }
+
+  func returnGenericInOutSendingViaHelperIf<T>(_ x: inout sending T) -> T {
+    let y = x
+    if getBool() {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingHelperDirectIf<T>(_ x: inout sending T) -> T {
+    if getBool() {
+      return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    } else {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingViaHelperVarIf<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    if getBool() {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    } else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingDirectlyElse<T>(_ x: inout sending T) -> T {
+    if getBool() {
+      print(x)
+      fatalError()
+    } else {
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingRegionLetElse<T>(_ x: inout sending T) -> T {
+    let y = x
+    if getBool() {
+      print(y)
+      fatalError()
+    } else {
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingRegionVarElse<T>(_ x: inout sending T, z: T) -> T {
+    var y = x
+    y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingViaHelperElse<T>(_ x: inout sending T, _ z: T) -> T {
+    let y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingHelperDirectElse<T>(_ x: inout sending T, _ z: T) -> T {
+    if getBool() {
+      print(x)
+      return z
+    } else {
+      return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingViaHelperVarElse<T>(_ x: inout sending T, _ z: T) -> T {
+    var y = x
+    y = x
+    if getBool() {
+      print(y)
+      return z
+    } else {
+      return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+      // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+  }
+
+  func returnGenericInOutSendingDirectlyFor<T>(_ x: inout sending T, _ z: T) -> T {
+    for _ in 0..<1 {
+      if getBool() {
+        return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+        // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(x)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingDirectlyFor2<T>(_ x: inout sending T, _ z: T) -> T {
+    for _ in 0..<1 {
+      if getBool() {
+        return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+        // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(x)
+    return z
+  }
+
+  func returnGenericInOutSendingRegionLetFor<T>(_ x: inout sending T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionLetFor2<T>(_ x: inout sending T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionLetFor3<T>(_ x: inout sending T, _ z: T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return z
+  }
+
+  func returnGenericInOutSendingRegionVarFor<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionVarFor2<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionVarFor3<T>(_ x: inout sending T, _ z: T) -> T {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return y // expected-warning {{'y' cannot be returned}}
+        // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return z
+  }
+
+  func returnGenericInOutSendingViaHelperFor<T>(_ x: inout sending T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(y)
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperFor2<T>(_ x: inout sending T) -> T {
+    let y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingHelperDirectFor<T>(_ x: inout sending T) -> T {
+    for _ in 0..<1 {
+      if getBool() {
+        return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperVarFor<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    for _ in 0..<1 {
+      if getBool() {
+        return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+        // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+      }
+    }
+    print(y)
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingDirectlyGuard<T>(_ x: inout sending T) -> T {
+    guard getBool() else {
+      print(x)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+    // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionLetGuard<T>(_ x: inout sending T) -> T {
+    let y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingRegionVarGuard<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    guard getBool() else {
+      print(y)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return y // expected-warning {{'y' cannot be returned}}
+    // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperGuard<T>(_ x: inout sending T) -> T {
+    let y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingHelperDirectGuard<T>(_ x: inout sending T) -> T {
+    guard getBool() else {
+      print(x)
+      return x // expected-warning {{'inout sending' parameter 'x' cannot be returned}}
+      // expected-note @-1 {{returning 'x' risks concurrent access as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return useValueAndReturnGeneric(x) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+
+  func returnGenericInOutSendingViaHelperVarGuard<T>(_ x: inout sending T) -> T {
+    var y = x
+    y = x
+    guard getBool() else {
+      print(y)
+      return y // expected-warning {{'y' cannot be returned}}
+      // expected-note @-1 {{returning 'y' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+    }
+    return useValueAndReturnGeneric(y) // expected-warning {{result of global function 'useValueAndReturnGeneric' cannot be returned}}
+    // expected-note @-1 {{returning result of global function 'useValueAndReturnGeneric' risks concurrent access to 'inout sending' parameter 'x' as caller assumes 'x' is not actor-isolated and result is main actor-isolated}}
+  }
+}
+
+//////////////////////
+// MARK: Misc Tests //
+//////////////////////
+
 func taskIsolatedCaptureInSendingClosureLiteral(_ x: NonSendableKlass) {
   Task { // expected-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
     print(x) // expected-note {{closure captures 'x' which is accessible to code in the current task}}
diff --git a/test/Concurrency/transfernonsendable_sending_results.swift b/test/Concurrency/transfernonsendable_sending_results.swift
index a3615b29546fe..f2deb7f6c661c 100644
--- a/test/Concurrency/transfernonsendable_sending_results.swift
+++ b/test/Concurrency/transfernonsendable_sending_results.swift
@@ -1,7 +1,9 @@
-// RUN: %target-swift-frontend -emit-sil -parse-as-library -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -verify-additional-prefix ni-
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault -verify-additional-prefix ni-ns-
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 ////////////////////////
 // MARK: Declarations //
@@ -141,7 +143,8 @@ func transferInAndOut(_ x: sending NonSendableKlass) -> sending NonSendableKlass
 
 func transferReturnArg(_ x: NonSendableKlass) -> sending NonSendableKlass {
   return x // expected-warning {{sending 'x' risks causing data races}}
-  // expected-note @-1 {{task-isolated 'x' cannot be a 'sending' result. task-isolated uses may race with caller uses}}
+  // expected-ni-note @-1 {{task-isolated 'x' cannot be a 'sending' result. task-isolated uses may race with caller uses}}
+  // expected-ni-ns-note @-2 {{task-isolated 'x' cannot be a 'sending' result. task-isolated uses may race with caller uses}}
 }
 
 // TODO: This will be fixed once I represent @MainActor on func types.
@@ -236,9 +239,10 @@ func asyncLetReabstractionThunkTest() async {
 }
 
 func asyncLetReabstractionThunkTest2() async {
-  // We emit the error here since we are returning a main actor isolated value.
+  // We emit the error here since we are returning a MainActor-isolated value.
   async let newValue: NonSendableKlass = await getMainActorValueAsync()
-  // expected-warning @-1 {{non-Sendable 'NonSendableKlass'-typed result can not be returned from main actor-isolated global function 'getMainActorValueAsync()' to nonisolated context}}
+  // expected-ni-warning @-1 {{non-Sendable 'NonSendableKlass'-typed result can not be returned from main actor-isolated global function 'getMainActorValueAsync()' to nonisolated context}}
+  // expected-ni-ns-warning @-2 {{non-Sendable 'NonSendableKlass'-typed result can not be returned from main actor-isolated global function 'getMainActorValueAsync()' to @concurrent context}}
 
   let _ = await newValue
 
@@ -259,9 +263,10 @@ func asyncLetReabstractionThunkTest2() async {
 }
 
 @MainActor func asyncLetReabstractionThunkTestGlobalActor2() async {
-  // We emit the error here since we are returning a main actor isolated value.
+  // We emit the error here since we are returning a MainActor-isolated value.
   async let newValue: NonSendableKlass = await getMainActorValueAsync()
-  // expected-warning @-1 {{non-Sendable 'NonSendableKlass'-typed result can not be returned from main actor-isolated global function 'getMainActorValueAsync()' to nonisolated context}}
+  // expected-ni-warning @-1 {{non-Sendable 'NonSendableKlass'-typed result can not be returned from main actor-isolated global function 'getMainActorValueAsync()' to nonisolated context}}
+  // expected-ni-ns-warning @-2 {{non-Sendable 'NonSendableKlass'-typed result can not be returned from main actor-isolated global function 'getMainActorValueAsync()' to @concurrent context}}
 
   let _ = await newValue
 
diff --git a/test/Concurrency/transfernonsendable_typechecker_errors.swift b/test/Concurrency/transfernonsendable_typechecker_errors.swift
new file mode 100644
index 0000000000000..b4d5531f1eb12
--- /dev/null
+++ b/test/Concurrency/transfernonsendable_typechecker_errors.swift
@@ -0,0 +1,174 @@
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -disable-availability-checking -verify %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+
+// REQUIRES: concurrency
+// REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
+
+// This test validates that for specific test cases around closures, we properly
+// emit errors in the type checker before we run sns. This ensures that we know that
+// these cases can't happen when SNS is enabled.
+
+class NonSendableKlass { // expected-note 2{{}}
+  var field: NonSendableKlass? = nil
+  var boolean: Bool = false
+
+  init() {}
+  init(_ x: NonSendableKlass) {
+  }
+
+  func asyncCall() async {}
+  func asyncCallWithIsolatedParameter(isolation: isolated (any Actor)? = #isolation) async {
+  }
+}
+
+@MainActor func transferToMain<T>(_ t: T) async {}
+
+var booleanFlag: Bool { false }
+
+class SendableKlass : @unchecked Sendable {}
+
+actor MyActor {
+  var klass = NonSendableKlass()
+  // expected-note @-1 7{{property declared here}}
+  final var finalKlass = NonSendableKlass()
+
+  func useKlass(_ x: NonSendableKlass) {}
+
+  func useSendableFunction(_: @Sendable () -> Void) {}
+  func useNonSendableFunction(_: () -> Void) {}
+  func doSomething() {}
+  @MainActor func useKlassMainActor(_ x: NonSendableKlass) {}
+}
+
+struct SingleFieldKlassBox { // expected-complete-note 2{{consider making struct 'SingleFieldKlassBox' conform to the 'Sendable' protocol}}
+  var k = NonSendableKlass()
+}
+
+struct TwoFieldKlassBox { // expected-note 2{{}}
+  var k1 = NonSendableKlass()
+  var k2 = NonSendableKlass()
+}
+
+class TwoFieldKlassClassBox {
+  var k1 = NonSendableKlass()
+  var k2 = NonSendableKlass()
+  var recursive: TwoFieldKlassClassBox? = nil
+}
+
+struct SendableGenericStruct : Sendable {
+  var x = SendableKlass()
+}
+
+enum MyEnum<T> {
+    case none
+    indirect case some(NonSendableKlass)
+    case more(T)
+}
+
+///////////
+// Tests //
+///////////
+
+extension MyActor {
+  func simpleClosureCaptureSelfThroughTupleWithFieldAccess() async {
+    // In this case, we erase that we accessed self so we hit a type checker
+    // error. We could make this a SNS error, but since in the other cases where
+    // we have a nonisolated non-async we are probably going to change it to be
+    // async as well making these errors go away.
+    let x = (self, 1)
+    let closure: () -> () = {
+      print(x.0.klass) // expected-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
+    }
+    await transferToMain(closure)
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+    // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+  }
+}
+
+func testSimpleLetClosureCaptureActorField() async {
+  let a = MyActor()
+  let closure = { print(a.klass) } // expected-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
+  await transferToMain(closure)
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+}
+
+func testSimpleLetClosureCaptureActorFieldThroughTuple() async {
+  let a = (MyActor(), 0)
+  let closure = { print(a.0.klass) } // expected-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
+  await transferToMain(closure)
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+}
+
+func testSimpleLetClosureCaptureActorFieldThroughOptional() async {
+  let a: MyActor? = MyActor()
+  let closure = { print(a!.klass) } // expected-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
+  await transferToMain(closure)
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+}
+
+func testSimpleVarClosureCaptureActorField() async {
+  let a = MyActor()
+  var closure = {}
+  closure = { print(a.klass) } // expected-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
+  await transferToMain(closure)
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+}
+
+func testSimpleVarClosureCaptureActorFieldThroughTuple() async {
+  let a = (MyActor(), 0)
+  var closure = {}
+  closure = { print(a.0.klass) } // expected-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
+  await transferToMain(closure)
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+}
+
+func testSimpleVarClosureCaptureActorFieldThroughOptional() async {
+  let a: MyActor? = MyActor()
+  var closure = {}
+  closure = { print(a!.klass) } // expected-error {{actor-isolated property 'klass' can not be referenced from a nonisolated context}}
+  await transferToMain(closure)
+  // expected-complete-warning @-1 {{passing argument of non-Sendable type '() -> ()' into main actor-isolated context may introduce data races}}
+  // expected-complete-note @-2 {{a function type must be marked '@Sendable' to conform to 'Sendable'}}
+}
+
+actor ActorWithSetter {
+  var field = NonSendableKlass()
+  var twoFieldBox = TwoFieldKlassBox()
+  var twoFieldBoxInTuple = (NonSendableKlass(), TwoFieldKlassBox())
+  var recursive: ActorWithSetter? = nil
+  var classBox = TwoFieldKlassClassBox()
+
+  // This triggers a crash in SILGen with tns enabled.
+  func recursive() async {
+    let x = NonSendableKlass()
+    await self.recursive!.twoFieldBoxInTuple.1.k2 = x
+    // expected-warning @-1 {{non-Sendable type '(NonSendableKlass, TwoFieldKlassBox)' of property 'twoFieldBoxInTuple' cannot exit actor-isolated context}}
+    // expected-warning @-2 {{non-Sendable type '(NonSendableKlass, TwoFieldKlassBox)' of property 'twoFieldBoxInTuple' cannot exit actor-isolated context}}
+
+    await transferToMain(x) // xpected-tns-warning {{call site passes `self` or a non-Sendable argument of this function to another thread, potentially yielding a race with the caller}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  }
+}
+
+final actor FinalActorWithSetter {
+  var field = NonSendableKlass()
+  var twoFieldBox = TwoFieldKlassBox()
+  var twoFieldBoxInTuple = (NonSendableKlass(), TwoFieldKlassBox())
+  var recursive: ActorWithSetter? = nil
+  var classBox = TwoFieldKlassClassBox()
+
+  // This triggers a crash in SILGen with tns enabled.
+  func recursive() async {
+    let x = NonSendableKlass()
+    await self.recursive!.twoFieldBoxInTuple.1.k2 = x
+    // expected-warning @-1 {{non-Sendable type '(NonSendableKlass, TwoFieldKlassBox)' of property 'twoFieldBoxInTuple' cannot exit actor-isolated context}}
+    // expected-warning @-2 {{non-Sendable type '(NonSendableKlass, TwoFieldKlassBox)' of property 'twoFieldBoxInTuple' cannot exit actor-isolated context}}
+
+    await transferToMain(x) // xpected-tns-warning {{call site passes `self` or a non-Sendable argument of this function to another thread, potentially yielding a race with the caller}}
+    // expected-complete-warning @-1 {{passing argument of non-Sendable type 'NonSendableKlass' into main actor-isolated context may introduce data races}}
+  }
+}
diff --git a/test/Concurrency/transfernonsendable_typed_errors.swift b/test/Concurrency/transfernonsendable_typed_errors.swift
index 72d45bac13cb5..f563ecfdd843a 100644
--- a/test/Concurrency/transfernonsendable_typed_errors.swift
+++ b/test/Concurrency/transfernonsendable_typed_errors.swift
@@ -1,7 +1,9 @@
 // RUN: %target-swift-frontend -swift-version 6 -Xllvm -sil-regionbasedisolation-force-use-of-typed-errors -emit-sil -o /dev/null %s -verify -target %target-swift-5.1-abi-triple
+// RUN: %target-swift-frontend -swift-version 6 -Xllvm -sil-regionbasedisolation-force-use-of-typed-errors -emit-sil -o /dev/null %s -verify -target %target-swift-5.1-abi-triple -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // READ THIS: This test is only intended to test typed errors that are fallback
 // error paths that are only invoked if we can't find a name for the value being
@@ -60,7 +62,7 @@ extension MyActor {
         _ = sc
 
         Task { // expected-error {{sending value of non-Sendable type '() async -> ()' risks causing data races}}
-          // expected-note @-1 {{Passing value of non-Sendable type '() async -> ()' as a 'sending' argument to initializer 'init(priority:operation:)' risks causing races in between local and caller code}}
+          // expected-note @-1 {{Passing value of non-Sendable type '() async -> ()' as a 'sending' argument to initializer 'init(name:priority:operation:)' risks causing races in between local and caller code}}
           _ = sc
         }
 
diff --git a/test/Concurrency/transfernonsendable_unavailable_conformance.swift b/test/Concurrency/transfernonsendable_unavailable_conformance.swift
index 883b1447b07fc..aac9d80b2bb87 100644
--- a/test/Concurrency/transfernonsendable_unavailable_conformance.swift
+++ b/test/Concurrency/transfernonsendable_unavailable_conformance.swift
@@ -1,8 +1,9 @@
-// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation -target %target-swift-5.1-abi-triple -verify  %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify  %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify  %s -o /dev/null -enable-upcoming-feature GlobalActorIsolatedTypesUsability -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_GlobalActorIsolatedTypesUsability
-// REQUIRES: swift_feature_RegionBasedIsolation
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // This test makes sure that we treat types with an unavailable Sendable
 // conformance as being non-Sendable.
diff --git a/test/Concurrency/transfernonsendable_warning_until_swift6.swift b/test/Concurrency/transfernonsendable_warning_until_swift6.swift
index 9f194ee040248..3548524be7c9e 100644
--- a/test/Concurrency/transfernonsendable_warning_until_swift6.swift
+++ b/test/Concurrency/transfernonsendable_warning_until_swift6.swift
@@ -1,6 +1,8 @@
 // RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -swift-version 6
+// RUN: %target-swift-frontend -emit-sil -strict-concurrency=complete -target %target-swift-5.1-abi-triple -verify %s -o /dev/null -swift-version 6 -enable-upcoming-feature NonisolatedNonsendingByDefault
 
 // REQUIRES: concurrency
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // This test makes sure that all of our warnings are errors in swift6 mode.
 
diff --git a/test/Concurrency/unavailable_from_async.swift b/test/Concurrency/unavailable_from_async.swift
index 7b27ede30342c..fd27763bbe76b 100644
--- a/test/Concurrency/unavailable_from_async.swift
+++ b/test/Concurrency/unavailable_from_async.swift
@@ -1,8 +1,8 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/UnavailableFunction.swiftmodule -module-name UnavailableFunction -strict-concurrency=complete %S/Inputs/UnavailableFunction.swift
-// RUN: %target-swift-frontend -verify -I %t %s -emit-sil -o /dev/null
-// RUN: %target-swift-frontend -verify -I %t %s -emit-sil -o /dev/null -strict-concurrency=targeted
-// RUN: %target-swift-frontend -verify -I %t %s -emit-sil -o /dev/null -strict-concurrency=complete
+// RUN: %target-swift-frontend -verify -verify-ignore-unrelated -I %t %s -emit-sil -o /dev/null
+// RUN: %target-swift-frontend -verify -verify-ignore-unrelated -I %t %s -emit-sil -o /dev/null -strict-concurrency=targeted
+// RUN: %target-swift-frontend -verify -verify-ignore-unrelated -I %t %s -emit-sil -o /dev/null -strict-concurrency=complete
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
diff --git a/test/Concurrency/unsafe_inherit_executor.swift b/test/Concurrency/unsafe_inherit_executor.swift
index fe2d873cb392f..7d7b54ca790f6 100644
--- a/test/Concurrency/unsafe_inherit_executor.swift
+++ b/test/Concurrency/unsafe_inherit_executor.swift
@@ -1,9 +1,9 @@
 // RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -emit-sil -o /dev/null -verify -disable-availability-checking %s
 // RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -emit-sil -o /dev/null -verify -disable-availability-checking %s -strict-concurrency=targeted
 // RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -emit-sil -o /dev/null -verify -disable-availability-checking %s -strict-concurrency=complete
-// RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -emit-sil -o /dev/null -verify -disable-availability-checking %s -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
-// REQUIRES: swift_feature_RegionBasedIsolation
+
+
 
 // expected-error @+1 {{non-async functions cannot inherit an executor}}
 @_unsafeInheritExecutor
@@ -11,7 +11,7 @@ func testNonAsync() {}
 
 @_unsafeInheritExecutor
 func testAsync() async {}
-// expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
+// expected-warning@-1{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
 
 struct A {
   // expected-error @+1 {{@_unsafeInheritExecutor may only be used on 'func' declarations}}
@@ -24,7 +24,7 @@ struct A {
 
   @_unsafeInheritExecutor
   func testAsync() async {}
-  // expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
+  // expected-warning@-1{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
 }
 
 
@@ -34,7 +34,7 @@ class NonSendableObject {
 
 @_unsafeInheritExecutor
 func useNonSendable(object: NonSendableObject) async {}
-// expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead; this is an error in the Swift 6 language mode}}{{35:1-24=}}{{36:46-46=, isolation: isolated (any Actor)? = #isolation}}
+// expected-warning@-1{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead; this is an error in the Swift 6 language mode}}{{35:1-24=}}{{36:46-46=, isolation: isolated (any Actor)? = #isolation}}
 
 actor MyActor {
   var object = NonSendableObject()
@@ -49,7 +49,7 @@ func inheritsIsolationProperly(isolation: isolated (any Actor)? = #isolation) as
 // @_unsafeInheritExecutor does not work with #isolation
 @_unsafeInheritExecutor
 func unsafeCallerA(x: Int) async {
-  // expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
+  // expected-warning@-1{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
 
   await inheritsIsolationProperly()
   // expected-error@-1{{#isolation (introduced by a default argument) cannot be used within an '@_unsafeInheritExecutor' function}}{{50:1-24=}}{{51:26-26=, isolation: isolated (any Actor)? = #isolation}}
@@ -57,7 +57,7 @@ func unsafeCallerA(x: Int) async {
 
 @_unsafeInheritExecutor
 func unsafeCallerB() async {
-  // expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
+  // expected-warning@-1{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
 
   await inheritsIsolationProperly(isolation: #isolation)
   // expected-error@-1{{#isolation cannot be used within an '@_unsafeInheritExecutor' function}}{{58:1-24=}}{{59:20-20=isolation: isolated (any Actor)? = #isolation}}
@@ -65,7 +65,7 @@ func unsafeCallerB() async {
 
 @_unsafeInheritExecutor
 func unsafeCallerC(x: Int, fn: () -> Void, fn2: () -> Void) async {
-  // expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
+  // expected-warning@-1{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
 
   await inheritsIsolationProperly()
   // expected-error@-1{{#isolation (introduced by a default argument) cannot be used within an '@_unsafeInheritExecutor' function}}{{66:1-24=}}{{67:28-28=, isolation: isolated (any Actor)? = #isolation, }}
@@ -73,7 +73,7 @@ func unsafeCallerC(x: Int, fn: () -> Void, fn2: () -> Void) async {
 
 @_unsafeInheritExecutor
 func unsafeCallerAvoidsNewLoop(x: some AsyncSequence<Int, Never>) async throws {
-  // expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
+  // expected-warning@-1{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
 
   for try await _ in x { }
 }
@@ -96,7 +96,7 @@ protocol P {}
 
 @_unsafeInheritExecutor
 func unsafeCallerAvoidsNewLoop() async throws {
-  // expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
+  // expected-warning@-1{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
 
   _ = await withUnsafeContinuation { (continuation: UnsafeContinuation<Int, Never>) in
     continuation.resume(returning: 5)
@@ -175,7 +175,7 @@ func unsafeClockCaller(
   existentialClock: any Clock,
   existentialCompositionClock: any P & Clock,
 ) async throws {
-  // expected-warning@-6{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
+  // expected-warning@-6{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
 
   _ = try! await specificClock.measure {
     try await Task.sleep(nanoseconds: 500)
@@ -196,4 +196,4 @@ func unsafeClockCaller(
 
 @_unsafeInheritExecutor
 func _unsafeInheritExecutor_hacky() async { }
-// expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
+// expected-warning@-1{{'@_unsafeInheritExecutor' is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
diff --git a/test/Concurrency/voucher_propagation.swift b/test/Concurrency/voucher_propagation.swift
index 3db2d3a505e87..2772812c87ec1 100644
--- a/test/Concurrency/voucher_propagation.swift
+++ b/test/Concurrency/voucher_propagation.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift %s -target %target-swift-5.1-abi-triple -o %t/voucher_propagation
 // RUN: %target-codesign %t/voucher_propagation
-// RUN: MallocStackLogging=1 %target-run %t/voucher_propagation
+// RUN: env MallocStackLogging=1 %target-run %t/voucher_propagation
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
@@ -228,7 +228,7 @@ func withVouchers(call: @Sendable @escaping (voucher_t?, voucher_t?, voucher_t?)
 
       // Clear any voucher that the call adopted.
       adopt(voucher: nil)
-      group.leave() // expected-complete-tns-warning {{capture of 'group' with non-sendable type 'DispatchGroup' in a '@Sendable' closure}}
+      group.leave() // expected-complete-tns-warning {{capture of 'group' with non-Sendable type 'DispatchGroup' in a '@Sendable' closure}}
     }
     group.wait()
 
@@ -417,7 +417,7 @@ if #available(SwiftStdlib 5.1, *) {
            _ = await (g, add)
 
            if await n.get() >= limit {
-             group.leave() // expected-warning 2{{capture of 'group' with non-sendable type 'DispatchGroup' in a '@Sendable' closure}}
+             group.leave() // expected-warning 2{{capture of 'group' with non-Sendable type 'DispatchGroup' in a '@Sendable' closure}}
            } else {
              await n.increment()
              await detachedTask()
diff --git a/test/Concurrency/weak_ref_sendability.swift b/test/Concurrency/weak_ref_sendability.swift
new file mode 100644
index 0000000000000..f0c6f9abdc5c4
--- /dev/null
+++ b/test/Concurrency/weak_ref_sendability.swift
@@ -0,0 +1,292 @@
+// RUN: %target-swift-frontend -emit-sil -swift-version 6 -target %target-swift-5.1-abi-triple -verify -verify-additional-prefix old- %s -o /dev/null
+// RUN: %target-swift-frontend -emit-sil -swift-version 6 -target %target-swift-5.1-abi-triple -verify -verify-additional-prefix new- -enable-upcoming-feature ImmutableWeakCaptures %s -o /dev/null
+
+// This test validates the behavior of transfer non sendable around ownership
+// constructs like non copyable types, consuming/borrowing parameters, and inout
+// parameters.
+
+// REQUIRES: concurrency
+// REQUIRES: swift_feature_ImmutableWeakCaptures
+
+final class S: Sendable {
+  func foo() {}
+}
+
+// expected-old-note@+2 13{{class 'NS' does not conform to the 'Sendable' protocol}}
+// expected-new-note@+1 12{{class 'NS' does not conform to the 'Sendable' protocol}}
+final class NS {
+  func bar() {}
+}
+
+func getS() -> S { S() }
+func getNS() -> NS { NS() }
+
+final class CheckOptionality1: Sendable {
+  // expected-old-error@+4 {{'weak' variable should have optional type 'S?'}}
+  // expected-old-error@+3 {{stored property 'x' of 'Sendable'-conforming class 'CheckOptionality1' is mutable}}
+  // expected-new-error@+2 {{'weak' variable should have optional type 'S?'}}
+  // expected-new-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckOptionality1' is mutable}}
+  weak var x: S = getS()
+}
+
+final class CheckOptionality2: Sendable {
+  // expected-error@+1 {{'weak' variable should have optional type 'S?'}}
+  weak let x: S = getS()
+}
+
+final class CheckSendability1: Sendable {
+  // expected-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckSendability1' is mutable}}
+  weak var x: S? = nil
+
+  weak var y: S? {
+    get { x }
+    set { x = newValue }
+  }
+}
+
+final class CheckSendability2: Sendable {
+  // expected-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckSendability2' is mutable}}
+  weak var x: NS? = nil
+}
+
+final class CheckSendability3: Sendable {
+  weak let x: S? = nil
+}
+
+final class CheckSendability4: Sendable {
+  // expected-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckSendability4' contains non-Sendable type 'NS'}}
+  weak let x: NS? = nil
+}
+
+final class CheckSendability5: Sendable {
+  // expected-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckSendability5' is mutable}}
+  unowned var x: S = getS()
+}
+
+final class CheckSendability6: Sendable {
+  // expected-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckSendability6' is mutable}}
+  unowned var x: NS = getNS()
+}
+
+final class CheckSendability7: Sendable {
+  unowned let x: S = getS()
+}
+
+final class CheckSendability8: Sendable {
+  // expected-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckSendability8' has non-Sendable type 'NS'}}
+  unowned let x: NS = getNS()
+}
+
+final class CheckSendability9: Sendable {
+  // expected-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckSendability9' is mutable}}
+  unowned(unsafe) var x: S = getS()
+}
+
+final class CheckSendability10: Sendable {
+  // expected-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckSendability10' is mutable}}
+  unowned(unsafe) var x: NS = getNS()
+}
+
+final class CheckSendability11: Sendable {
+  unowned(unsafe) let x: S = getS()
+}
+
+final class CheckSendability12: Sendable {
+  // expected-error@+1 {{stored property 'x' of 'Sendable'-conforming class 'CheckSendability12' has non-Sendable type 'NS'}}
+  unowned(unsafe) let x: NS = getNS()
+}
+
+
+func checkWeakCapture1(_ strongRef: S) -> @Sendable () -> Void {
+  // expected-warning@+1 {{weak variable 'weakRef' was never mutated; consider changing to 'let' constant}}
+  weak var weakRef: S? = strongRef
+  return {
+    // expected-error@+1 {{reference to captured var 'weakRef' in concurrently-executing code}}
+    weakRef?.foo()
+  }
+}
+
+func checkWeakCapture2(_ strongRef: S) -> @Sendable () -> Void {
+  weak let weakRef: S? = strongRef
+  return {
+    weakRef?.foo()
+  }
+}
+
+func checkWeakCapture3(_ strongRef: S) -> @Sendable () -> Void {
+  return { [weak weakRef = strongRef] in
+    // TODO: Add expected old error, when https://github.com/swiftlang/swift/issues/80014 is fixed
+    // See also https://forums.swift.org/t/lets-debug-missing-rbi-data-race-diagnostics/78910
+    weakRef?.foo()
+    // expected-new-error@+1 {{cannot assign to value: 'weakRef' is an immutable capture}}
+    weakRef = nil
+  }
+}
+
+func checkWeakCapture4(_ strongRef: NS) -> @Sendable () -> Void {
+  // expected-warning@+1 {{weak variable 'weakRef' was never mutated; consider changing to 'let' constant}}
+  weak var weakRef: NS? = strongRef
+  return {
+    // expected-error@+2 {{capture of 'weakRef' with non-Sendable type 'NS?' in a '@Sendable' closure}}
+    // expected-error@+1 {{reference to captured var 'weakRef' in concurrently-executing code}}
+    weakRef?.bar()
+  }
+}
+
+func checkWeakCapture5(_ strongRef: NS) -> @Sendable () -> Void {
+  weak let weakRef: NS? = strongRef
+  return {
+    // expected-error@+1 {{capture of 'weakRef' with non-Sendable type 'NS?' in a '@Sendable' closure}}
+    weakRef?.bar()
+  }
+}
+
+func checkWeakCapture6(_ strongRef: NS) -> @Sendable () -> Void {
+  return { [weak weakRef = strongRef] in
+    // expected-old-error@+3 {{capture of 'weakRef' with non-Sendable type 'NS?' in a '@Sendable' closure}}
+    // For some reason the next error masks this error.
+    // This case is split into two, to verify that when unmasked error is triggered.
+    weakRef?.bar()
+    // expected-new-error@+1 {{cannot assign to value: 'weakRef' is an immutable capture}}
+    weakRef = nil
+  }
+}
+
+func checkWeakCapture7(_ strongRef: NS) -> @Sendable () -> Void {
+  return { [weak weakRef = strongRef] in
+    // expected-error@+1 {{capture of 'weakRef' with non-Sendable type 'NS?' in a '@Sendable' closure}}
+    weakRef?.bar()
+  }
+}
+
+func checkUnownedCapture1(_ strongRef: S) -> @Sendable () -> Void {
+  // expected-old-warning@+2 {{variable 'unownedRef' was never mutated; consider changing to 'let' constant}}
+  // expected-new-warning@+1 {{variable 'unownedRef' was never mutated; consider changing to 'let' constant}}
+  unowned var unownedRef: S = strongRef
+  return {
+    // expected-old-error@+2 {{reference to captured var 'unownedRef' in concurrently-executing code}}
+    // expected-new-error@+1 {{reference to captured var 'unownedRef' in concurrently-executing code}}
+    unownedRef.foo()
+  }
+}
+
+func checkUnownedCapture2(_ strongRef: S) -> @Sendable () -> Void {
+  unowned let unownedRef: S = strongRef
+  return {
+    unownedRef.foo()
+  }
+}
+
+func checkUnownedCapture3(_ strongRef: S) -> @Sendable () -> Void {
+  return { [unowned unownedRef = strongRef] in
+    // TODO: Add expected old error, when https://github.com/swiftlang/swift/issues/80014 is fixed
+    // See also https://forums.swift.org/t/lets-debug-missing-rbi-data-race-diagnostics/78910
+    unownedRef.foo()
+    // expected-old-error@+2 {{cannot assign to value: 'unownedRef' is an immutable capture}}
+    // expected-new-error@+1 {{cannot assign to value: 'unownedRef' is an immutable capture}}
+    unownedRef = strongRef
+  }
+}
+
+func checkUnownedCapture4(_ strongRef: NS) -> @Sendable () -> Void {
+  // expected-old-warning@+2 {{variable 'unownedRef' was never mutated; consider changing to 'let' constant}}
+  // expected-new-warning@+1 {{variable 'unownedRef' was never mutated; consider changing to 'let' constant}}
+  unowned var unownedRef: NS = strongRef
+  return {
+    // expected-error@+2 {{capture of 'unownedRef' with non-Sendable type 'NS' in a '@Sendable' closure}}
+    // expected-error@+1 {{reference to captured var 'unownedRef' in concurrently-executing code}}
+    unownedRef.bar()
+  }
+}
+
+func checkUnownedCapture5(_ strongRef: NS) -> @Sendable () -> Void {
+  unowned let unownedRef: NS = strongRef
+  return {
+    // expected-error@+1 {{capture of 'unownedRef' with non-Sendable type 'NS' in a '@Sendable' closure}}
+    unownedRef.bar()
+  }
+}
+
+func checkUnownedCapture6(_ strongRef: NS) -> @Sendable () -> Void {
+  return { [unowned unownedRef = strongRef] in
+    // For some reason the next error masks this error.
+    // This case is split into two, to verify that when unmasked error is triggered.
+    unownedRef.bar()
+    // expected-old-error@+2 {{cannot assign to value: 'unownedRef' is an immutable capture}}
+    // expected-new-error@+1 {{cannot assign to value: 'unownedRef' is an immutable capture}}
+    unownedRef = strongRef
+  }
+}
+
+func checkUnownedCapture7(_ strongRef: NS) -> @Sendable () -> Void {
+  return { [unowned unownedRef = strongRef] in
+    // expected-error@+1 {{capture of 'unownedRef' with non-Sendable type 'NS' in a '@Sendable' closure}}
+    unownedRef.bar()
+  }
+}
+
+func checkUnsafeCapture1(_ strongRef: S) -> @Sendable () -> Void {
+  // expected-old-warning@+2 {{variable 'unownedRef' was never mutated; consider changing to 'let' constant}}
+  // expected-new-warning@+1 {{variable 'unownedRef' was never mutated; consider changing to 'let' constant}}
+  unowned(unsafe) var unownedRef: S = strongRef
+  return {
+    // expected-old-error@+2 {{reference to captured var 'unownedRef' in concurrently-executing code}}
+    // expected-new-error@+1 {{reference to captured var 'unownedRef' in concurrently-executing code}}
+    unownedRef.foo()
+  }
+}
+
+func checkUnsafeCapture2(_ strongRef: S) -> @Sendable () -> Void {
+  unowned(unsafe) let unownedRef: S = strongRef
+  return {
+    unownedRef.foo()
+  }
+}
+
+func checkUnsafeCapture3(_ strongRef: S) -> @Sendable () -> Void {
+  return { [unowned(unsafe) unownedRef = strongRef] in
+    // TODO: Add expected old error, when https://github.com/swiftlang/swift/issues/80014 is fixed
+    // See also https://forums.swift.org/t/lets-debug-missing-rbi-data-race-diagnostics/78910
+    unownedRef.foo()
+    // expected-old-error@+2 {{cannot assign to value: 'unownedRef' is an immutable capture}}
+    // expected-new-error@+1 {{cannot assign to value: 'unownedRef' is an immutable capture}}
+    unownedRef = strongRef
+  }
+}
+
+func checkUnsafeCapture4(_ strongRef: NS) -> @Sendable () -> Void {
+  // expected-old-warning@+2 {{variable 'unownedRef' was never mutated; consider changing to 'let' constant}}
+  // expected-new-warning@+1 {{variable 'unownedRef' was never mutated; consider changing to 'let' constant}}
+  unowned(unsafe) var unownedRef: NS = strongRef
+  return {
+    // expected-error@+2 {{capture of 'unownedRef' with non-Sendable type 'NS' in a '@Sendable' closure}}
+    // expected-error@+1 {{reference to captured var 'unownedRef' in concurrently-executing code}}
+    unownedRef.bar()
+  }
+}
+
+func checkUnsafeCapture5(_ strongRef: NS) -> @Sendable () -> Void {
+  unowned(unsafe) let unownedRef: NS = strongRef
+  return {
+    // expected-error@+1 {{capture of 'unownedRef' with non-Sendable type 'NS' in a '@Sendable' closure}}
+    unownedRef.bar()
+  }
+}
+
+func checkUnsafeCapture6(_ strongRef: NS) -> @Sendable () -> Void {
+  return { [unowned(unsafe) unownedRef = strongRef] in
+    // For some reason the next error masks this error.
+    // This case is split into two, to verify that when unmasked error is triggered.
+    unownedRef.bar()
+    // expected-old-error@+2 {{cannot assign to value: 'unownedRef' is an immutable capture}}
+    // expected-new-error@+1 {{cannot assign to value: 'unownedRef' is an immutable capture}}
+    unownedRef = strongRef
+  }
+}
+
+func checkUnsafeCapture7(_ strongRef: NS) -> @Sendable () -> Void {
+  return { [unowned(unsafe) unownedRef = strongRef] in
+    // expected-error@+1 {{capture of 'unownedRef' with non-Sendable type 'NS' in a '@Sendable' closure}}
+    unownedRef.bar()
+  }
+}
diff --git a/test/Concurrency/where_clause_main_resolution.swift b/test/Concurrency/where_clause_main_resolution.swift
index 4caeb9c724e64..3c81370b7e3f0 100644
--- a/test/Concurrency/where_clause_main_resolution.swift
+++ b/test/Concurrency/where_clause_main_resolution.swift
@@ -25,19 +25,19 @@ protocol App {
 // CHECK-SAME: interface_type="<Self where Self : App> (Self.Type) -> () async -> ()"
 
 extension App where Configuration == Config1 {
-// CHECK-CONFIG1: (func_decl {{.*}}implicit "$main()" interface_type="(MainType.Type) -> () -> ()"
+// CHECK-CONFIG1: (func_decl {{.*}}implicit range=[{{.*}}:[[@LINE+20]]:1 - line:[[@LINE+20]]:1] "$main()" interface_type="(MainType.Type) -> () -> ()"
 // CHECK-CONFIG1: [[SOURCE_FILE]]:[[# @LINE+1 ]]
     static func main() { }
 }
 
 extension App where Configuration == Config2 {
-// CHECK-CONFIG2: (func_decl {{.*}}implicit "$main()" interface_type="(MainType.Type) -> () async -> ()"
+// CHECK-CONFIG2: (func_decl {{.*}}implicit range=[{{.*}}:[[@LINE+14]]:1 - line:[[@LINE+14]]:1] "$main()" interface_type="(MainType.Type) -> () async -> ()"
 // CHECK-CONFIG2: [[SOURCE_FILE]]:[[# @LINE+1 ]]
     static func main() async { }
 }
 
 extension App where Configuration == Config3 {
-// CHECK-CONFIG3-ASYNC: (func_decl {{.*}}implicit "$main()" interface_type="(MainType.Type) -> () async -> ()"
+// CHECK-CONFIG3-ASYNC: (func_decl {{.*}}implicit range=[{{.*}}:[[@LINE+8]]:1 - line:[[@LINE+8]]:1] "$main()" interface_type="(MainType.Type) -> () async -> ()"
 // CHECK-CONFIG3-ASYNC: [[SOURCE_FILE]]:[[DEFAULT_ASYNCHRONOUS_MAIN_LINE]]
 }
 
diff --git a/test/ConstExtraction/ExtractCalls.swift b/test/ConstExtraction/ExtractCalls.swift
index 19451444ba431..75cda8c04b532 100644
--- a/test/ConstExtraction/ExtractCalls.swift
+++ b/test/ConstExtraction/ExtractCalls.swift
@@ -7,12 +7,15 @@
 protocol MyProto {}
 
 public struct Foo : MyProto {
-    let init1 = Bar()
-    let init2: Bat = .init()
-    let init3 = Bat(buz: "hello", fuz: adder(2, 3))
-    static var init4: Bar? = Bar()
+  let init1 = Bar()
+  let init2: Bat = .init()
+  let init3 = Bat(buz: "hello", fuz: adder(2, 3))
+  static var init4: Bar? = Bar()
 
-    let func1: Int = adder(2, 3)
+  let init5 = Hux()
+  let init6 = Hux(fuz: 42)
+
+  let func1: Int = adder(2, 3)
 }
 
 extension Foo {
@@ -26,16 +29,19 @@ func adder(_ x: Int, _ y: Int) -> Int {
 }
 
 public struct Bar {}
-public struct Bat {
-    let buz: String
+
+public class Bat {
+    let buz: String?
     let fuz: Int
 
-    init(buz: String = "", fuz: Int = 0) {
+    init(buz: String? = nil, fuz: Int = 0) {
         self.buz = buz
         self.fuz = fuz
     }
 }
 
+public class Hux: Bat {}
+
 // CHECK: [
 // CHECK-NEXT:  {
 // CHECK-NEXT:    "typeName": "ExtractCalls.Foo",
@@ -82,9 +88,8 @@ public struct Bat {
 // CHECK-NEXT:          "arguments": [
 // CHECK-NEXT:            {
 // CHECK-NEXT:              "label": "buz",
-// CHECK-NEXT:              "type": "Swift.String",
-// CHECK-NEXT:              "valueKind": "RawLiteral",
-// CHECK-NEXT:              "value": ""
+// CHECK-NEXT:              "type": "Swift.Optional<Swift.String>",
+// CHECK-NEXT:              "valueKind": "NilLiteral"
 // CHECK-NEXT:            },
 // CHECK-NEXT:            {
 // CHECK-NEXT:              "label": "fuz",
@@ -109,7 +114,7 @@ public struct Bat {
 // CHECK-NEXT:          "arguments": [
 // CHECK-NEXT:            {
 // CHECK-NEXT:              "label": "buz",
-// CHECK-NEXT:              "type": "Swift.String",
+// CHECK-NEXT:              "type": "Swift.Optional<Swift.String>",
 // CHECK-NEXT:              "valueKind": "RawLiteral",
 // CHECK-NEXT:              "value": "hello"
 // CHECK-NEXT:            },
@@ -139,13 +144,65 @@ public struct Bat {
 // CHECK-NEXT:        }
 // CHECK-NEXT:      },
 // CHECK-NEXT:      {
+// CHECK-NEXT:        "label": "init5",
+// CHECK-NEXT:        "type": "ExtractCalls.Hux",
+// CHECK-NEXT:        "mangledTypeName": "n/a - deprecated",
+// CHECK-NEXT:        "isStatic": "false",
+// CHECK-NEXT:        "isComputed": "false",
+// CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractCalls.swift",
+// CHECK-NEXT:        "line": 15,
+// CHECK-NEXT:        "valueKind": "InitCall",
+// CHECK-NEXT:        "value": {
+// CHECK-NEXT:          "type": "ExtractCalls.Hux",
+// CHECK-NEXT:          "arguments": [
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "label": "buz",
+// CHECK-NEXT:              "type": "Swift.Optional<Swift.String>",
+// CHECK-NEXT:              "valueKind": "NilLiteral"
+// CHECK-NEXT:            },
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "label": "fuz",
+// CHECK-NEXT:              "type": "Swift.Int",
+// CHECK-NEXT:              "valueKind": "RawLiteral",
+// CHECK-NEXT:              "value": "0"
+// CHECK-NEXT:            }
+// CHECK-NEXT:          ]
+// CHECK-NEXT:        }
+// CHECK-NEXT:      },
+// CHECK-NEXT:      {
+// CHECK-NEXT:        "label": "init6",
+// CHECK-NEXT:        "type": "ExtractCalls.Hux",
+// CHECK-NEXT:        "mangledTypeName": "n/a - deprecated",
+// CHECK-NEXT:        "isStatic": "false",
+// CHECK-NEXT:        "isComputed": "false",
+// CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractCalls.swift",
+// CHECK-NEXT:        "line": 16,
+// CHECK-NEXT:        "valueKind": "InitCall",
+// CHECK-NEXT:        "value": {
+// CHECK-NEXT:          "type": "ExtractCalls.Hux",
+// CHECK-NEXT:          "arguments": [
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "label": "buz",
+// CHECK-NEXT:              "type": "Swift.Optional<Swift.String>",
+// CHECK-NEXT:              "valueKind": "NilLiteral"
+// CHECK-NEXT:            },
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "label": "fuz",
+// CHECK-NEXT:              "type": "Swift.Int",
+// CHECK-NEXT:              "valueKind": "RawLiteral",
+// CHECK-NEXT:              "value": "42"
+// CHECK-NEXT:            }
+// CHECK-NEXT:          ]
+// CHECK-NEXT:        }
+// CHECK-NEXT:      },
+// CHECK-NEXT:      {
 // CHECK-NEXT:        "label": "func1",
 // CHECK-NEXT:        "type": "Swift.Int",
 // CHECK-NEXT:        "mangledTypeName": "n/a - deprecated",        
 // CHECK-NEXT:        "isStatic": "false",
 // CHECK-NEXT:        "isComputed": "false",
 // CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractCalls.swift",
-// CHECK-NEXT:        "line": 15,
+// CHECK-NEXT:        "line": 18,
 // CHECK-NEXT:         "valueKind": "FunctionCall",
 // CHECK-NEXT:         "value": {
 // CHECK-NEXT:           "name": "adder",
@@ -186,7 +243,7 @@ public struct Bat {
 // CHECK-NEXT:        "isStatic": "false",
 // CHECK-NEXT:        "isComputed": "true",
 // CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractCalls.swift",
-// CHECK-NEXT:        "line": 21,
+// CHECK-NEXT:        "line": 24,
 // CHECK-NEXT:        "valueKind": "InitCall",
 // CHECK-NEXT:        "value": {
 // CHECK-NEXT:          "type": "ExtractCalls.Foo.Boo",
diff --git a/test/ConstExtraction/ExtractConstantsFromMembersAttributeExperimental.swift b/test/ConstExtraction/ExtractConstantsFromMembersAttributeExperimental.swift
index b6c37809c6180..50ebd1eb3d299 100644
--- a/test/ConstExtraction/ExtractConstantsFromMembersAttributeExperimental.swift
+++ b/test/ConstExtraction/ExtractConstantsFromMembersAttributeExperimental.swift
@@ -1,4 +1,4 @@
 // RUN: %target-typecheck-verify-swift %s
 
-// expected-error@+1{{@extractConstantsFromMembers requires '-enable-experimental-feature ExtractConstantsFromMembers'}}
+// expected-error@+1{{'@extractConstantsFromMembers' requires '-enable-experimental-feature ExtractConstantsFromMembers'}}
 @extractConstantsFromMembers protocol MyProto {}
diff --git a/test/ConstExtraction/ExtractKeyPaths.swift b/test/ConstExtraction/ExtractKeyPaths.swift
index ae261ebe0bcff..6721fdd4e1091 100644
--- a/test/ConstExtraction/ExtractKeyPaths.swift
+++ b/test/ConstExtraction/ExtractKeyPaths.swift
@@ -1,9 +1,11 @@
 // RUN: %empty-directory(%t)
 // RUN: echo "[MyProto]" > %t/protocols.json
 
-// RUN: %target-swift-frontend -typecheck -emit-const-values-path %t/ExtractKeyPaths.swiftconstvalues -const-gather-protocols-file %t/protocols.json -primary-file %s
+// RUN: %target-swift-frontend -enable-upcoming-feature InferSendableFromCaptures -typecheck -emit-const-values-path %t/ExtractKeyPaths.swiftconstvalues -const-gather-protocols-file %t/protocols.json -primary-file %s
 // RUN: cat %t/ExtractKeyPaths.swiftconstvalues 2>&1 | %FileCheck %s
 
+// REQUIRES: swift_feature_InferSendableFromCaptures
+
 protocol MyProto {}
 
 public struct MyType {
@@ -59,7 +61,7 @@ public struct KeyPaths: MyProto {
 // CHECK-NEXT:        "isStatic": "true",
 // CHECK-NEXT:        "isComputed": "false",
 // CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractKeyPaths.swift",
-// CHECK-NEXT:       "line": 31,
+// CHECK-NEXT:       "line": 33,
 // CHECK-NEXT:        "valueKind": "KeyPath",
 // CHECK-NEXT:        "value": {
 // CHECK-NEXT:          "path": "foo",
@@ -79,7 +81,7 @@ public struct KeyPaths: MyProto {
 // CHECK-NEXT:        "isStatic": "true",
 // CHECK-NEXT:        "isComputed": "false",
 // CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractKeyPaths.swift",
-// CHECK-NEXT:        "line": 32,
+// CHECK-NEXT:        "line": 34,
 // CHECK-NEXT:        "valueKind": "KeyPath",
 // CHECK-NEXT:        "value": {
 // CHECK-NEXT:          "path": "foo",
@@ -99,7 +101,7 @@ public struct KeyPaths: MyProto {
 // CHECK-NEXT:        "isStatic": "true",
 // CHECK-NEXT:        "isComputed": "false",
 // CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractKeyPaths.swift",
-// CHECK-NEXT:        "line": 33,
+// CHECK-NEXT:        "line": 35,
 // CHECK-NEXT:        "valueKind": "KeyPath",
 // CHECK-NEXT:        "value": {
 // CHECK-NEXT:          "path": "foo",
@@ -119,7 +121,7 @@ public struct KeyPaths: MyProto {
 // CHECK-NEXT:        "isStatic": "true",
 // CHECK-NEXT:        "isComputed": "false",
 // CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractKeyPaths.swift",
-// CHECK-NEXT:        "line": 34,
+// CHECK-NEXT:        "line": 36,
 // CHECK-NEXT:        "valueKind": "KeyPath",
 // CHECK-NEXT:        "value": {
 // CHECK-NEXT:          "path": "bar",
@@ -139,7 +141,7 @@ public struct KeyPaths: MyProto {
 // CHECK-NEXT:        "isStatic": "true",
 // CHECK-NEXT:        "isComputed": "false",
 // CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractKeyPaths.swift",
-// CHECK-NEXT:        "line": 35,
+// CHECK-NEXT:        "line": 37,
 // CHECK-NEXT:        "valueKind": "KeyPath",
 // CHECK-NEXT:        "value": {
 // CHECK-NEXT:          "path": "bar",
@@ -154,12 +156,12 @@ public struct KeyPaths: MyProto {
 // CHECK-NEXT:      },
 // CHECK-NEXT:       {
 // CHECK-NEXT:        "label": "nestedKeyPath",
-// CHECK-NEXT:        "type": "Swift.WritableKeyPath<ExtractKeyPaths.MyType, Swift.String>",
+// CHECK-NEXT:        "type": "any Swift.WritableKeyPath<ExtractKeyPaths.MyType, Swift.String> & Swift.Sendable",
 // CHECK-NEXT:        "mangledTypeName": "n/a - deprecated",
 // CHECK-NEXT:        "isStatic": "true",
 // CHECK-NEXT:        "isComputed": "false",
 // CHECK-NEXT:        "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractKeyPaths.swift",
-// CHECK-NEXT:        "line": 36,
+// CHECK-NEXT:        "line": 38,
 // CHECK-NEXT:        "valueKind": "KeyPath",
 // CHECK-NEXT:        "value": {
 // CHECK-NEXT:         "path": "nested.foo.bar.baz",
diff --git a/test/ConstExtraction/ExtractOpenExistential.swift b/test/ConstExtraction/ExtractOpenExistential.swift
new file mode 100644
index 0000000000000..1c2f784492c82
--- /dev/null
+++ b/test/ConstExtraction/ExtractOpenExistential.swift
@@ -0,0 +1,70 @@
+// RUN: %empty-directory(%t)
+// RUN: echo "[MyProto]" > %t/protocols.json
+
+// RUN: %target-swift-frontend -typecheck -emit-const-values-path %t/ExtractOpenExistential.swiftconstvalues -const-gather-protocols-file %t/protocols.json -primary-file %s
+// RUN: cat %t/ExtractOpenExistential.swiftconstvalues 2>&1 | %FileCheck %s
+
+protocol MyProto {}
+
+protocol ExampleProtocol {
+    var protocolProperty: String { get }
+}
+
+struct ConcreteType: ExampleProtocol {
+    let protocolProperty: String = "Concrete implementation"
+}
+
+func useExistential(_ example: any ExampleProtocol) -> String {
+    return example.protocolProperty
+}
+
+public struct External: MyProto {
+    static let existentialValue = useExistential(ConcreteType())
+}
+
+
+// CHECK: [
+// CHECK-NEXT:   {
+// CHECK-NEXT:     "typeName": "ExtractOpenExistential.External",
+// CHECK-NEXT:     "mangledTypeName": "22ExtractOpenExistential8ExternalV",
+// CHECK-NEXT:     "kind": "struct",
+// CHECK-NEXT:     "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractOpenExistential.swift",
+// CHECK-NEXT:     "line": 21,
+// CHECK-NEXT:     "conformances": [
+// CHECK-NEXT:       "ExtractOpenExistential.MyProto"
+// CHECK-NEXT:     ],
+// CHECK-NEXT:     "allConformances": [
+// CHECK-NEXT:       {
+// CHECK-NEXT:         "protocolName": "ExtractOpenExistential.MyProto"
+// CHECK-NEXT:         "conformanceDefiningModule": "ExtractOpenExistential"
+// CHECK-NEXT:       }
+// CHECK-NEXT:     ],
+// CHECK-NEXT:     "associatedTypeAliases": [],
+// CHECK-NEXT:     "properties": [
+// CHECK-NEXT:       {
+// CHECK-NEXT:         "label": "existentialValue",
+// CHECK-NEXT:         "type": "Swift.String",
+// CHECK-NEXT:         "mangledTypeName": "n/a - deprecated",
+// CHECK-NEXT:         "isStatic": "true",
+// CHECK-NEXT:         "isComputed": "false",
+// CHECK-NEXT:         "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractOpenExistential.swift",
+// CHECK-NEXT:         "line": 22,
+// CHECK-NEXT:         "valueKind": "FunctionCall",
+// CHECK-NEXT:         "value": {
+// CHECK-NEXT:           "name": "useExistential",
+// CHECK-NEXT:           "arguments": [
+// CHECK-NEXT:             {
+// CHECK-NEXT:               "label": "",
+// CHECK-NEXT:               "type": "any ExtractOpenExistential.ExampleProtocol",
+// CHECK-NEXT:               "valueKind": "InitCall",
+// CHECK-NEXT:               "value": {
+// CHECK-NEXT:                 "type": "ExtractOpenExistential.ConcreteType",
+// CHECK-NEXT:                 "arguments": []
+// CHECK-NEXT:               }
+// CHECK-NEXT:             }
+// CHECK-NEXT:           ]
+// CHECK-NEXT:         }
+// CHECK-NEXT:       }
+// CHECK-NEXT:     ]
+// CHECK-NEXT:   }
+// CHECK-NEXT: ]
diff --git a/test/ConstValues/CImports.swift b/test/ConstValues/CImports.swift
index c134dc4366bae..ee19dfc6e9ce3 100644
--- a/test/ConstValues/CImports.swift
+++ b/test/ConstValues/CImports.swift
@@ -1,9 +1,11 @@
 // Constant globals should "work" when referencing C-imported constants
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146952876
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
+// RUN: %target-swift-frontend -emit-ir -primary-file %t/main.swift -parse-as-library -import-bridging-header %t/bridging_header.h -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %t/main.swift -parse-as-library -import-bridging-header %t/bridging_header.h -enable-experimental-feature CompileTimeValues
 
 //--- bridging_header.h
diff --git a/test/ConstValues/Conditions.swift b/test/ConstValues/Conditions.swift
index 74ebc9212dad5..b30bb152d8758 100644
--- a/test/ConstValues/Conditions.swift
+++ b/test/ConstValues/Conditions.swift
@@ -1,6 +1,8 @@
 // Constant globals on comparisons and conditions
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146953097 
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
 
 @const let constGlobal1: Int = true ? 1 : 0
diff --git a/test/ConstValues/DiagModules.swift b/test/ConstValues/DiagModules.swift
index a821a50fe96f5..33693e932082c 100644
--- a/test/ConstValues/DiagModules.swift
+++ b/test/ConstValues/DiagModules.swift
@@ -1,10 +1,11 @@
 // Constant globals should "work" even when used across files in non-WMO builds.
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
-// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-as-library -enable-experimental-feature CompileTimeValues
-// RUN: %target-swift-frontend -emit-ir -I %t %t/Main.swift -verify -enable-experimental-feature CompileTimeValues
+// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -I %t %t/Main.swift -verify -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 
 //--- MyModule.swift
 
@@ -17,5 +18,5 @@ public func foo() -> Int {
 import MyModule
 
 @const let constGlobal1: Int = foo()
-// expected-error@-1 {{@const value should be initialized with a compile-time value}}
+// expected-error@-1 {{'@const' value should be initialized with a compile-time value}}
 // expected-error@-2 {{global variable must be a compile-time constant}} // Remove this once we common out the diagnostics
diff --git a/test/ConstValues/DiagModulesSyntactic.swift b/test/ConstValues/DiagModulesSyntactic.swift
new file mode 100644
index 0000000000000..742b65fffbaf0
--- /dev/null
+++ b/test/ConstValues/DiagModulesSyntactic.swift
@@ -0,0 +1,20 @@
+// Constant globals should "work" even when used across files in non-WMO builds.
+// REQUIRES: swift_feature_CompileTimeValues
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-as-library -enable-experimental-feature CompileTimeValues
+// RUN: %target-swift-frontend -emit-ir -I %t %t/Main.swift -verify -enable-experimental-feature CompileTimeValues
+
+//--- MyModule.swift
+
+public func foo() -> Int {
+	return 42
+}
+
+//--- Main.swift
+
+import MyModule
+
+@const let constGlobal1: Int = foo()
+// expected-error@-1 {{not supported in a '@const' expression}}
diff --git a/test/ConstValues/DiagNotConst.swift b/test/ConstValues/DiagNotConst.swift
index 187f404243f9a..177eaf7cff42b 100644
--- a/test/ConstValues/DiagNotConst.swift
+++ b/test/ConstValues/DiagNotConst.swift
@@ -1,9 +1,10 @@
 // Constant globals rejected for not being constant values
 // REQUIRES: swift_feature_CompileTimeValues
-// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -verify -enable-experimental-feature CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -verify -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 
 @const let a: Bool = Bool.random()
-// expected-error@-1 {{@const value should be initialized with a compile-time value}}
+// expected-error@-1 {{'@const' value should be initialized with a compile-time value}}
 // expected-error@-2 {{global variable must be a compile-time constant}} // Remove this once we common out the diagnostics
 
 func foo() -> Int {
@@ -11,5 +12,5 @@ func foo() -> Int {
 }
 
 @const let b: Int = foo()
-// expected-error@-1 {{@const value should be initialized with a compile-time value}}
+// expected-error@-1 {{'@const' value should be initialized with a compile-time value}}
 // expected-error@-2 {{global variable must be a compile-time constant}} // Remove this once we common out the diagnostics
diff --git a/test/ConstValues/DiagNotConstSyntactic.swift b/test/ConstValues/DiagNotConstSyntactic.swift
new file mode 100644
index 0000000000000..8d522281f4b4d
--- /dev/null
+++ b/test/ConstValues/DiagNotConstSyntactic.swift
@@ -0,0 +1,13 @@
+// Constant globals rejected for not being constant values
+// REQUIRES: swift_feature_CompileTimeValues
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -verify -enable-experimental-feature CompileTimeValues
+
+@const let a: Bool = Bool.random()
+// expected-error@-1 {{not supported in a '@const' expression}}
+
+func foo() -> Int {
+	return 42 * Int.random(in: 0 ..< 10)
+}
+
+@const let b: Int = foo()
+// expected-error@-1 {{not supported in a '@const' expression}}
diff --git a/test/ConstValues/DiagReferenceCycle.swift b/test/ConstValues/DiagReferenceCycle.swift
index 84513b950a946..8d1501deeed92 100644
--- a/test/ConstValues/DiagReferenceCycle.swift
+++ b/test/ConstValues/DiagReferenceCycle.swift
@@ -1,6 +1,8 @@
 // Constant globals referencing other constant globals and forming a cycle
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146957382
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -verify -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -verify -enable-experimental-feature CompileTimeValues
 
 @const let a: Int = c
diff --git a/test/ConstValues/FloatintPointLiterals.swift b/test/ConstValues/FloatintPointLiterals.swift
index 50dd59adc2025..54bc41037f377 100644
--- a/test/ConstValues/FloatintPointLiterals.swift
+++ b/test/ConstValues/FloatintPointLiterals.swift
@@ -1,5 +1,7 @@
 // Constant globals on simple floating-point literals
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
 
 @const let constGlobal1 = 42.0
diff --git a/test/ConstValues/FunctionTypes.swift b/test/ConstValues/FunctionTypes.swift
index a087c2827375a..fc1f5fa0d8c8e 100644
--- a/test/ConstValues/FunctionTypes.swift
+++ b/test/ConstValues/FunctionTypes.swift
@@ -1,6 +1,7 @@
 // Constant globals on function types / function pointers
 // REQUIRES: swift_feature_CompileTimeValues
-// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 
 func foo_void_to_void() {}
 func foo_int_to_int(x: Int) -> Int { return 42 }
diff --git a/test/ConstValues/FunctionTypesSyntactic.swift b/test/ConstValues/FunctionTypesSyntactic.swift
new file mode 100644
index 0000000000000..3f969f516ac8e
--- /dev/null
+++ b/test/ConstValues/FunctionTypesSyntactic.swift
@@ -0,0 +1,30 @@
+// Constant globals on function types / function pointers
+// REQUIRES: swift_feature_CompileTimeValues
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -verify
+
+func foo_void_to_void() {}
+func foo_int_to_int(x: Int) -> Int { return 42 }
+
+@const let constGlobalA1: ()->() = { }
+// expected-error@-1{{closures not supported in a '@const' expression}}
+@const let constGlobalA2: @convention(c) ()->() = { }
+// expected-error@-1{{closures not supported in a '@const' expression}}
+@const let constGlobalA3: @convention(thin) ()->() = { }
+// expected-error@-1{{only 'convention(c)' function values are supported in a '@const' expression}}
+
+@const let constGlobalB1: ()->() = foo_void_to_void // TODO: Diagnose the type of the variable as not eligigle for '@const' (not the init expression)
+@const let constGlobalB2: @convention(c) ()->() = foo_void_to_void
+@const let constGlobalB3: @convention(thin) ()->() = foo_void_to_void
+// expected-error@-1{{only 'convention(c)' function values are supported in a '@const' expression}}
+
+@const let constGlobalC1: (Int)->(Int) = { _ in return 42 }
+// expected-error@-1{{closures not supported in a '@const' expression}}
+@const let constGlobalC2: @convention(c) (Int)->(Int) = { _ in return 42 }
+// expected-error@-1{{closures not supported in a '@const' expression}}
+@const let constGlobalC3: @convention(thin) (Int)->(Int) = { _ in return 42 }
+// expected-error@-1{{only 'convention(c)' function values are supported in a '@const' expression}}
+
+@const let constGlobalD1: (Int)->(Int) = foo_int_to_int
+@const let constGlobalD2: @convention(c) (Int)->(Int) = foo_int_to_int
+@const let constGlobalD3: @convention(thin) (Int)->(Int) = foo_int_to_int
+// expected-error@-1{{only 'convention(c)' function values are supported in a '@const' expression}}
diff --git a/test/ConstValues/InlineArrays.swift b/test/ConstValues/InlineArrays.swift
index e6bfa97dcb4b2..a952bfa7a71bd 100644
--- a/test/ConstValues/InlineArrays.swift
+++ b/test/ConstValues/InlineArrays.swift
@@ -1,6 +1,8 @@
 // Constant globals on inline arrays
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146954768
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -disable-availability-checking -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -disable-availability-checking -enable-experimental-feature CompileTimeValues
 
 @const let constGlobal1: InlineArray = [1, 2, 3]
diff --git a/test/ConstValues/IntegerArithmetic.swift b/test/ConstValues/IntegerArithmetic.swift
index 7c47fe68105c4..33d105e43187b 100644
--- a/test/ConstValues/IntegerArithmetic.swift
+++ b/test/ConstValues/IntegerArithmetic.swift
@@ -1,5 +1,7 @@
 // Constant globals on integer arithmetics
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
 
 @const let constGlobal1: Int = 42
diff --git a/test/ConstValues/IntegerExpressions.swift b/test/ConstValues/IntegerExpressions.swift
index 2317f205ab30f..28604c91ff932 100644
--- a/test/ConstValues/IntegerExpressions.swift
+++ b/test/ConstValues/IntegerExpressions.swift
@@ -1,6 +1,8 @@
 // Constant globals on integer expressions
 // REQUIRES: swift_feature_CompileTimeValues
-// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -verify
+// REQUIRES: swift_feature_CompileTimeValuesPreview
+// REQUIRES: optimized_stdlib
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview -verify
 
 @const let constGlobal1: Int = (42 + 42 + 42) / 3
 @const let constGlobal2: Int = MemoryLayout<UInt32>.size + 4
diff --git a/test/ConstValues/IntegerExpressionsSyntactic.swift b/test/ConstValues/IntegerExpressionsSyntactic.swift
new file mode 100644
index 0000000000000..c9ca04662a9a1
--- /dev/null
+++ b/test/ConstValues/IntegerExpressionsSyntactic.swift
@@ -0,0 +1,11 @@
+// Constant globals on integer expressions
+// REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: optimized_stdlib
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -verify
+
+@const let constGlobal1: Int = (42 + 42 + 42) / 3
+@const let constGlobal2: Int = MemoryLayout<UInt32>.size + 4
+// expected-error@-1{{in a '@const' expression}}
+@const let constGlobal3: Int = Int(17.0 / 3.5)
+@const let constGlobal4: Int = constGlobal1 + 1
+@const let constGlobal5: Int = -constGlobal1 + 1
diff --git a/test/ConstValues/IntegerLiterals.swift b/test/ConstValues/IntegerLiterals.swift
index 236bd1d3b7d1e..43d548b8fc692 100644
--- a/test/ConstValues/IntegerLiterals.swift
+++ b/test/ConstValues/IntegerLiterals.swift
@@ -1,5 +1,7 @@
 // Constant globals on simple integer literals
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -verify -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -verify -enable-experimental-feature CompileTimeValues
 
 @const let constGlobal1: Int = 42
diff --git a/test/ConstValues/Modules.swift b/test/ConstValues/Modules.swift
index 29ecf29fe2a2f..c1f2fd4de06e9 100644
--- a/test/ConstValues/Modules.swift
+++ b/test/ConstValues/Modules.swift
@@ -1,9 +1,13 @@
 // Constant values should be able to call "const" functions from other modules
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146953110
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
+// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -I %t %t/Main.swift -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
+
 // RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-as-library -enable-experimental-feature CompileTimeValues
 // RUN: %target-swift-frontend -emit-ir -I %t %t/Main.swift -enable-experimental-feature CompileTimeValues
 
diff --git a/test/ConstValues/NegativeUnaryReference.swift b/test/ConstValues/NegativeUnaryReference.swift
index ada198b883e8c..d604c91e2f395 100644
--- a/test/ConstValues/NegativeUnaryReference.swift
+++ b/test/ConstValues/NegativeUnaryReference.swift
@@ -1,6 +1,8 @@
 // Constant globals referencing other constant globals in their initializer expressions
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146954110
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
 
 @const let a: Int = 42
diff --git a/test/ConstValues/NonWMO.swift b/test/ConstValues/NonWMO.swift
index 505c356146438..627c19ac6d89a 100644
--- a/test/ConstValues/NonWMO.swift
+++ b/test/ConstValues/NonWMO.swift
@@ -1,9 +1,11 @@
 // Constant globals should "work" even when used across files in non-WMO builds.
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146405994
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
+// RUN: %target-swift-frontend -emit-ir -primary-file %s/file1.swift -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s/file1.swift -parse-as-library -enable-experimental-feature CompileTimeValues
 
 //--- file1.swift
diff --git a/test/ConstValues/Optionals.swift b/test/ConstValues/Optionals.swift
index 85886f4340a5b..9ac4a01515c87 100644
--- a/test/ConstValues/Optionals.swift
+++ b/test/ConstValues/Optionals.swift
@@ -1,6 +1,8 @@
 // Constant globals on optionals
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
 
 @const let constGlobal1: Int? = 42
diff --git a/test/ConstValues/Parameters.swift b/test/ConstValues/Parameters.swift
index 6870088d77d26..daa24ab86f707 100644
--- a/test/ConstValues/Parameters.swift
+++ b/test/ConstValues/Parameters.swift
@@ -1,6 +1,7 @@
 // Constant globals on simple integer literals
 // REQUIRES: swift_feature_CompileTimeValues
-// RUN: %target-swift-frontend -emit-sil -primary-file %s -verify -enable-experimental-feature CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-sil -primary-file %s -verify -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 
 func bar(@const _ thing: UInt) -> UInt {
     return thing
@@ -15,4 +16,3 @@ func foo() {
     let _ = bar(UInt.random(in: 0..<10))
     // expected-error@-1 {{expected a compile-time value argument for a '@const' parameter}}
 }
-
diff --git a/test/ConstValues/ParametersSyntactic.swift b/test/ConstValues/ParametersSyntactic.swift
new file mode 100644
index 0000000000000..896c7b9f6ad1b
--- /dev/null
+++ b/test/ConstValues/ParametersSyntactic.swift
@@ -0,0 +1,18 @@
+// Constant globals on simple integer literals
+// REQUIRES: swift_feature_CompileTimeValues
+// RUN: %target-swift-frontend -emit-sil -primary-file %s -verify -enable-experimental-feature CompileTimeValues
+
+func bar(@const _ thing: UInt) -> UInt {
+    return thing
+}
+
+func foo() {
+    let _ = bar(42)
+    let _ = bar(0xf000f000)
+    #if _pointerBitWidth(_64)
+    let _ = bar(0xf000f000_f000f000)
+    #endif
+    let _ = bar(UInt.random(in: 0..<10))
+    // expected-error@-1 {{expected a compile-time value argument for a '@const' parameter}}
+    // expected-error@-2 {{not supported in a '@const' expression}}
+}
diff --git a/test/ConstValues/References.swift b/test/ConstValues/References.swift
index 5c2f1518c64c5..df20f66e69541 100644
--- a/test/ConstValues/References.swift
+++ b/test/ConstValues/References.swift
@@ -1,5 +1,7 @@
 // Constant globals referencing other constant globals in their initializer expressions
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
 
 @const let a: Int = 42
diff --git a/test/ConstValues/StringTuples.swift b/test/ConstValues/StringTuples.swift
index e1225c83bcd03..52ed30a37554d 100644
--- a/test/ConstValues/StringTuples.swift
+++ b/test/ConstValues/StringTuples.swift
@@ -1,6 +1,8 @@
 // Constant globals on tuples
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146953330
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
 
 @const let constGlobalStringTuple: (Int, String) = (42, "Foo")
diff --git a/test/ConstValues/Strings.swift b/test/ConstValues/Strings.swift
index 74707ffe0f819..1c69c3976466b 100644
--- a/test/ConstValues/Strings.swift
+++ b/test/ConstValues/Strings.swift
@@ -1,6 +1,8 @@
 // Constant globals on strings
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146953748
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
 
 @const let constGlobal1: String = "hello"
diff --git a/test/ConstValues/TopLevel.swift b/test/ConstValues/TopLevel.swift
index b6ad2bdbc97ef..86711c9e718e4 100644
--- a/test/ConstValues/TopLevel.swift
+++ b/test/ConstValues/TopLevel.swift
@@ -1,8 +1,11 @@
 // Constant globals should "work" even in top-level code mode.
 // REQUIRES: swift_feature_CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
 // REQUIRES: rdar146954355
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
+
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -enable-experimental-feature CompileTimeValues
 // RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
 
-
 @const let constGlobal: Int = 42
diff --git a/test/ConstValues/Tuples.swift b/test/ConstValues/Tuples.swift
index e1026d9379915..7bf569da66905 100644
--- a/test/ConstValues/Tuples.swift
+++ b/test/ConstValues/Tuples.swift
@@ -1,10 +1,14 @@
 // Constant globals on tuples
 // REQUIRES: swift_feature_CompileTimeValues
-// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues
+// REQUIRES: swift_feature_CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -enable-experimental-feature CompileTimeValuesPreview
+// RUN: %target-swift-frontend -emit-ir -primary-file %s -parse-as-library -enable-experimental-feature CompileTimeValues -verify
 
 @const let constGlobal1: Int = 42
 @const let constGlobal2: (Int, Int) = (42, 42)
 @const let constGlobal3: (Int, Bool) = (42, true)
 @const let constGlobal4: (Int, (Int, Int)) = (42, (42, 42))
 @const let constGlobal5: (Int, Float) = (42, 42.0)
-@const let constGlobal7: (UInt64, StaticString, @convention(c) ()->Int) = (42, "hi", { return 42 })
+
+// Closure call not supported in syntactically-validated mode
+@const let constGlobal7: (UInt64, StaticString, @convention(c) ()->Int) = (42, "hi", { return 42 }) // expected-error {{not supported in a '@const' expression}}
diff --git a/test/Constraints/ambiguous_specialized_name_diagnostics.swift b/test/Constraints/ambiguous_specialized_name_diagnostics.swift
index 90d363b8f1e88..3ecf7d8d6cfe9 100644
--- a/test/Constraints/ambiguous_specialized_name_diagnostics.swift
+++ b/test/Constraints/ambiguous_specialized_name_diagnostics.swift
@@ -11,7 +11,7 @@
 // RUN:   -emit-module-path %t/B.swiftmodule
 
 // RUN: %target-swift-frontend -typecheck %t/src/main.swift \
-// RUN:   -module-name main -I %t -verify
+// RUN:   -module-name main -I %t -verify -verify-ignore-unrelated
 
 // https://github.com/apple/swift/issues/67799
 
diff --git a/test/Constraints/argument_matching.swift b/test/Constraints/argument_matching.swift
index 2b78c083000c4..2d653c9ac7462 100644
--- a/test/Constraints/argument_matching.swift
+++ b/test/Constraints/argument_matching.swift
@@ -1461,7 +1461,7 @@ func testClosures() {
 
 func acceptAutoclosure(f: @autoclosure () -> Int) { }
 func produceInt() -> Int { }
-acceptAutoclosure(f: produceInt) // expected-error{{add () to forward @autoclosure parameter}} {{32-32=()}}
+acceptAutoclosure(f: produceInt) // expected-error{{add () to forward '@autoclosure' parameter}} {{32-32=()}}
 
 // -------------------------------------------
 // Trailing closures
@@ -1821,3 +1821,12 @@ struct Issue75527 {
     fn(0) // Make sure the argument label does not escape here.
   }
 }
+
+do {
+  func f(p: Int, _: String) {}
+  // FIXME: Wrong expected argument type.
+  // expected-error@+2:5 {{cannot convert value of type 'Int' to expected argument type 'String'}}
+  // expected-error@+1:8 {{cannot convert value of type 'String' to expected argument type 'Int'}}
+  f(0, "")
+  // expected-error@-1:4 {{missing argument label 'p:' in call}}{{5-5=p: }}
+}
diff --git a/test/Constraints/array_literal.swift b/test/Constraints/array_literal.swift
index 9927002e81e7d..39017b52c6475 100644
--- a/test/Constraints/array_literal.swift
+++ b/test/Constraints/array_literal.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -target %target-swift-5.1-abi-triple
 
 struct IntList : ExpressibleByArrayLiteral {
   typealias Element = Int
diff --git a/test/Constraints/assignment.swift b/test/Constraints/assignment.swift
index 4ccdf8951bee3..f97b7e4c25031 100644
--- a/test/Constraints/assignment.swift
+++ b/test/Constraints/assignment.swift
@@ -88,3 +88,16 @@ class С_56396 {
     self.callback = callback // expected-error {{cannot assign value of type '(Self) -> Void' to type '(С_56396) -> Void'}}
   }
 }
+
+// https://github.com/swiftlang/swift/issues/82397
+func testFunctionAssignsWithOptionals(fn: @escaping () -> () -> Void) {
+  let _: (() -> () -> Void)? = fn
+  let _: (() -> () -> Void)?? = fn
+
+  class Super {}
+  class Sub: Super {}
+
+  let b: () -> () -> Sub = { { return Sub() } }
+  let _: (() -> () -> Super)? = b
+  let _: (() -> () -> Super)?? = b
+}
diff --git a/test/Constraints/async.swift b/test/Constraints/async.swift
index 52f7a44e46d55..9985f169c0a22 100644
--- a/test/Constraints/async.swift
+++ b/test/Constraints/async.swift
@@ -212,10 +212,9 @@ func test_async_calls_in_async_context(v: Int) async {
   }
 
   // Only implicit `.init` should be accepted with a warning due type-checker previously picking an incorrect overload.
-  // FIXME: This should produce a warning once type-checker performance hacks are removed.
-  _ = Test(v) // Temporary okay
+  _ = Test(v) // expected-warning {{expression is 'async' but is not marked with 'await'; this is an error in the Swift 6 language mode}} expected-note {{call is 'async'}}
   _ = Test.init(v) // expected-error {{expression is 'async' but is not marked with 'await'}} expected-note {{call is 'async'}}
 
   Test.test(v) // expected-error {{expression is 'async' but is not marked with 'await'}} expected-note {{call is 'async'}}
-  Test(v).test(v) // expected-error {{expression is 'async' but is not marked with 'await'}} expected-note {{call is 'async'}}
+  Test(v).test(v) // expected-error {{expression is 'async' but is not marked with 'await'}} expected-note 2 {{call is 'async'}}
 }
diff --git a/test/Constraints/availability.swift b/test/Constraints/availability.swift
deleted file mode 100644
index ff28cc08e9c21..0000000000000
--- a/test/Constraints/availability.swift
+++ /dev/null
@@ -1,88 +0,0 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4
-
-// Ensure that we do not select the unavailable failable init as the
-// only solution and then fail to typecheck.
-protocol P {}
-
-class C : P {
-  @available(swift, obsoleted: 4)
-  public init?(_ c: C) {
-  }
-
-  public init<T : P>(_ c: T) {}
-}
-
-func f(c: C) {
-  let _: C? = C(c)
-}
-
-// rdar://problem/60047439 - unable to disambiguate expression based on availability
-func test_contextual_member_with_availability() {
-  struct A {
-    static var foo: A = A()
-  }
-
-  struct B {
-    @available(*, unavailable, renamed: "bar")
-    static var foo: B = B()
-  }
-
-  struct Test {
-    init(_: A) {}
-    init(_: B) {}
-  }
-
-  _ = Test(.foo) // Ok
-}
-
-@available(*, unavailable)
-func unavailableFunction(_ x: Int) -> Bool { true } // expected-note {{'unavailableFunction' has been explicitly marked unavailable here}}
-
-/// https://github.com/apple/swift/issues/55700
-/// Availability checking not working in the `where` clause of a `for` loop
-func f_55700(_ arr: [Int]) {
-  for x in arr where unavailableFunction(x) {} // expected-error {{'unavailableFunction' is unavailable}}
-}
-
-// rdar://101814209
-public struct Box<T> {
-  @usableFromInline
-  let value: T
-}
-
-@available(macOS, unavailable)
-extension Box where T == Int {
-  @usableFromInline
-  init(value: T) {
-    self.value = value
-  }
-}
-
-@available(macOS, unavailable)
-@_alwaysEmitIntoClient public func aeicFunction() {
-  // Select the unavailable @usableFromInline init over the synthesized internal
-  // memberwise initializer.
-  _ = Box(value: 42)
-}
-
-// rdar://87403752 - ambiguity with member declared in unavailable extension
-struct HasUnavailableExtesion {
-}
-
-@available(*, unavailable)
-extension HasUnavailableExtesion {
-  static var foo: Self = HasUnavailableExtesion()
-}
-
-func test_contextual_member_with_unavailable_extension() {
-  struct A {
-    static var foo: A = A()
-  }
-
-  struct Test {
-    init(_: A) {}
-    init(_: HasUnavailableExtesion) {}
-  }
-
-  _ = Test(.foo) // Ok `A.foo` since `foo` from `HasUnavailableExtesion` is unavailable
-}
diff --git a/test/Constraints/bidirectional_conversions.swift b/test/Constraints/bidirectional_conversions.swift
index de5077c507a32..43620893f9693 100644
--- a/test/Constraints/bidirectional_conversions.swift
+++ b/test/Constraints/bidirectional_conversions.swift
@@ -6,7 +6,7 @@ import CoreGraphics
 
 /////////////
 
-struct G<T> {  // expected-note {{arguments to generic parameter 'T' ('CGFloat?' and 'CGFloat') are expected to be equal}}
+struct G<T> {
   var t: T
 }
 
@@ -32,8 +32,7 @@ func foo4(x: (() -> ())?, y: @escaping @convention(block) () -> ()) -> G<() -> (
 
 func foo5(x: CGFloat?, y: Double) -> G<CGFloat> {
   let g = G(t: x ?? y)
-  // FIXME
-  return g  // expected-error {{cannot convert return expression of type 'G<CGFloat?>' to return type 'G<CGFloat>'}}
+  return g
 }
 
 func foo6(x: Double?, y: CGFloat) -> G<Double> {
diff --git a/test/Constraints/bridging-nsnumber-and-nsvalue.swift.gyb b/test/Constraints/bridging-nsnumber-and-nsvalue.swift.gyb
index 044d9fdd6a730..a58ee8587afc1 100644
--- a/test/Constraints/bridging-nsnumber-and-nsvalue.swift.gyb
+++ b/test/Constraints/bridging-nsnumber-and-nsvalue.swift.gyb
@@ -62,7 +62,7 @@ func bridgeNSNumberBackToSpecificType(object: ${ObjectType},
   _ = object as? ${Type}
   _ = object as! ${Type}
 
-  _ = optional as ${Type}? // expected-error{{is not convertible to}} expected-note {{use 'as!'}}
+  _ = optional as ${Type}? // expected-error{{cannot convert value of type '${ObjectType}?' to type '${Type}?' in coercion}} expected-note {{arguments to generic parameter 'Wrapped' ('${ObjectType}' and '${Type}') are expected to be equal}}
   _ = optional is ${Type}?
   _ = optional as? ${Type}?
   _ = optional as! ${Type}?
diff --git a/test/Constraints/bridging.swift b/test/Constraints/bridging.swift
index dd8dae4661590..17d55377d372f 100644
--- a/test/Constraints/bridging.swift
+++ b/test/Constraints/bridging.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
@@ -283,24 +283,29 @@ func rdar19831698() {
 // <rdar://problem/19836341> Incorrect fixit for NSString? to String? conversions
 func rdar19836341(_ ns: NSString?, vns: NSString?) {
   var vns = vns
-  let _: String? = ns // expected-error{{cannot convert value of type 'NSString?' to specified type 'String?'}}{{22-22= as String?}}
-  var _: String? = ns // expected-error{{cannot convert value of type 'NSString?' to specified type 'String?'}}{{22-22= as String?}}
+  let _: String? = ns // expected-error{{cannot assign value of type 'NSString?' to type 'String?'}}{{22-22= as String?}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('NSString' and 'String') are expected to be equal}}
+  var _: String? = ns // expected-error{{cannot assign value of type 'NSString?' to type 'String?'}}{{22-22= as String?}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('NSString' and 'String') are expected to be equal}}
 
   // Important part about below diagnostic is that from-type is described as
   // 'NSString?' and not '@lvalue NSString?':
-  let _: String? = vns // expected-error{{cannot convert value of type 'NSString?' to specified type 'String?'}}{{23-23= as String?}}
-  var _: String? = vns // expected-error{{cannot convert value of type 'NSString?' to specified type 'String?'}}{{23-23= as String?}}
+  let _: String? = vns // expected-error{{cannot assign value of type 'NSString?' to type 'String?'}}{{23-23= as String?}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('NSString' and 'String') are expected to be equal}}
+  var _: String? = vns // expected-error{{cannot assign value of type 'NSString?' to type 'String?'}}{{23-23= as String?}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('NSString' and 'String') are expected to be equal}}
 
   vns = ns
 }
 
 // <rdar://problem/20029786> Swift compiler sometimes suggests changing "as!" to "as?!"
 func rdar20029786(_ ns: NSString?) {
-  var s: String = ns ?? "str" as String as String // expected-error{{'NSString' is not implicitly convertible to 'String'; did you mean to use 'as' to explicitly convert?}} {{19-19=(}} {{50-50=) as String}}
-  // expected-error@-1 {{cannot convert value of type 'String' to expected argument type 'NSString'}} {{50-50= as NSString}}
-  var s2 = ns ?? "str" as String as String // expected-error {{cannot convert value of type 'String' to expected argument type 'NSString'}}{{43-43= as NSString}}
+  var s: String = ns ?? "str" as String as String
+  // expected-error@-1 {{cannot convert value of type 'NSString?' to expected argument type 'String?'}} {{21-21= as String?}}
+  var s2 = ns ?? "str" as String as String // expected-error {{binary operator '??' cannot be applied to operands of type 'NSString?' and 'String'}}
 
-  let s3: NSString? = "str" as String? // expected-error {{cannot convert value of type 'String?' to specified type 'NSString?'}}{{39-39= as NSString?}}
+  let s3: NSString? = "str" as String? // expected-error {{cannot assign value of type 'String?' to type 'NSString?'}}{{39-39= as NSString?}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('String' and 'NSString') are expected to be equal}}
 
   var s4: String = ns ?? "str" // expected-error{{'NSString' is not implicitly convertible to 'String'; did you mean to use 'as' to explicitly convert?}} {{20-20=(}} {{31-31=) as String}}
   var s5: String = (ns ?? "str") as String // fixed version
@@ -308,7 +313,8 @@ func rdar20029786(_ ns: NSString?) {
 
 // Make sure more complicated cast has correct parenthesization
 func castMoreComplicated(anInt: Int?) {
-  let _: (NSObject & NSCopying)? = anInt // expected-error{{cannot convert value of type 'Int?' to specified type '(any NSObject & NSCopying)?'}}{{41-41= as (any NSObject & NSCopying)?}}
+  let _: (NSObject & NSCopying)? = anInt // expected-error{{cannot assign value of type 'Int?' to type '(any NSObject & NSCopying)?'}}{{41-41= as (any NSObject & NSCopying)?}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('Int' and 'any NSObject & NSCopying') are expected to be equal}}
 }
 
 
@@ -367,6 +373,28 @@ func forceUniversalBridgeToAnyObject<T, U: KnownClassProtocol>(a: T, b: U, c: An
   _ = z
 }
 
+do {
+  func f(an : Any, oan: Any?) -> AnyObject? {
+    let a1 : AnyObject
+    a1 = an
+    // expected-error@-1:8 {{value of type 'Any' expected to be an instance of a class or class-constrained type in assignment}}{{none}}
+    // expected-note@-2:8 {{cast 'Any' to 'AnyObject' or use 'as!' to force downcast to a more specific type to access members}}{{12-12= as AnyObject}}
+    let a2 : AnyObject?
+    a2 = an
+    // expected-error@-1:10 {{value of type 'Any' expected to be an instance of a class or class-constrained type in assignment}}{{12-12= as AnyObject}}
+    let a3 : AnyObject!
+    a3 = an
+    // expected-error@-1:10 {{value of type 'Any' expected to be an instance of a class or class-constrained type in assignment}}{{12-12= as AnyObject}}
+
+    let obj: AnyObject = an
+    // expected-error@-1:26 {{value of type 'Any' expected to be instance of class or class-constrained type}}{{none}}
+    // expected-note@-2:26 {{cast 'Any' to 'AnyObject' or use 'as!' to force downcast to a more specific type to access members}}{{28-28= as AnyObject}}
+
+    return oan
+    // expected-error@-1:12 {{return expression of type 'Any' expected to be an instance of a class or class-constrained type}}{{15-15= as AnyObject}}
+  }
+}
+
 func bridgeAnyContainerToAnyObject(x: [Any], y: [NSObject: Any]) {
   var z: AnyObject
   z = x as AnyObject
diff --git a/test/Constraints/casts_objc.swift b/test/Constraints/casts_objc.swift
index e9630761472e2..5ecc4b946ca26 100644
--- a/test/Constraints/casts_objc.swift
+++ b/test/Constraints/casts_objc.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated %s
 // REQUIRES: objc_interop
 
 import Foundation
@@ -82,8 +82,8 @@ func optionalityMismatchingCasts(f: CGFloat, n: NSNumber, fooo: CGFloat???,
                                  nooo: NSNumber???) {
   _ = f as NSNumber?
   _ = f as NSNumber??
-  let _ = fooo as NSNumber?? // expected-error{{'CGFloat???' is not convertible to 'NSNumber??'}}
-  //expected-note@-1 {{did you mean to use 'as!' to force downcast?}} {{16-18=as!}}
+  let _ = fooo as NSNumber?? // expected-error{{cannot convert value of type 'CGFloat???' to type 'NSNumber??' in coercion}}
+  //expected-note@-1 {{arguments to generic parameter 'Wrapped' ('CGFloat?' and 'NSNumber') are expected to be equal}}
   let _ = fooo as NSNumber???? // okay: injects extra optionals
 }
 
diff --git a/test/Constraints/casts_swift6.swift b/test/Constraints/casts_swift6.swift
index 5161a493e9dbd..17cbd89100741 100644
--- a/test/Constraints/casts_swift6.swift
+++ b/test/Constraints/casts_swift6.swift
@@ -25,9 +25,9 @@ func test_compatibility_coercions(_ arr: [Int], _ optArr: [Int]?, _ dict: [Strin
 
   // Make sure we error on the following in Swift 6 mode.
   _ = id(arr) as [String] // expected-error {{conflicting arguments to generic parameter 'T' ('[Int]' vs. '[String]')}}
-  _ = (arr ?? []) as [String] // expected-error {{conflicting arguments to generic parameter 'T' ('[String]' vs. '[Int]')}}
-  _ = (arr ?? [] ?? []) as [String] // expected-error {{conflicting arguments to generic parameter 'T' ('[String]' vs. '[Int]')}}
-  // expected-error@-1{{conflicting arguments to generic parameter 'T' ('[String]' vs. '[Int]')}}
+  _ = (arr ?? []) as [String] // expected-error {{conflicting arguments to generic parameter 'T' ('[Int]' vs. '[String]')}}
+  _ = (arr ?? [] ?? []) as [String] // expected-error {{conflicting arguments to generic parameter 'T' ('[Int]' vs. '[String]')}}
+  // expected-error@-1{{conflicting arguments to generic parameter 'T' ('[Int]' vs. '[String]')}}
   _ = (optArr ?? []) as [String] // expected-error {{conflicting arguments to generic parameter 'T' ('[Int]' vs. '[String]'}}
 
   _ = (arr ?? []) as [String]? // expected-error {{'[Int]' is not convertible to '[String]?'}}
diff --git a/test/Constraints/closures.swift b/test/Constraints/closures.swift
index c964bb9a0d008..941317f3ac956 100644
--- a/test/Constraints/closures.swift
+++ b/test/Constraints/closures.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 func myMap<T1, T2>(_ array: [T1], _ fn: (T1) -> T2) -> [T2] {}
 
@@ -55,7 +55,7 @@ func inoutToSharedConversions() {
 // Autoclosure
 func f1(f: @autoclosure () -> Int) { }
 func f2() -> Int { }
-f1(f: f2) // expected-error{{add () to forward @autoclosure parameter}}{{9-9=()}}
+f1(f: f2) // expected-error{{add () to forward '@autoclosure' parameter}}{{9-9=()}}
 f1(f: 5)
 
 // Ternary in closure
@@ -273,7 +273,7 @@ func someFunc(_ foo: ((String) -> String)?,
 
 func verify_NotAC_to_AC_failure(_ arg: () -> ()) {
   func takesAC(_ arg: @autoclosure () -> ()) {}
-  takesAC(arg) // expected-error {{add () to forward @autoclosure parameter}} {{14-14=()}}
+  takesAC(arg) // expected-error {{add () to forward '@autoclosure' parameter}} {{14-14=()}}
 }
 
 // https://github.com/apple/swift/issues/43681
@@ -803,7 +803,6 @@ overloaded { print("hi"); print("bye") } // multiple expression closure without
 // expected-error@-1 {{ambiguous use of 'overloaded'}}
 
 func not_overloaded(_ handler: () -> Int) {}
-// expected-note@-1 {{'not_overloaded' declared here}}
 
 not_overloaded { } // empty body
 // expected-error@-1 {{cannot convert value of type '()' to closure result type 'Int'}}
@@ -1156,7 +1155,7 @@ struct R_76250381<Result, Failure: Error> {
 func rdar77022842(argA: Bool? = nil, argB: Bool? = nil) {
   if let a = argA ?? false, if let b = argB ?? {
     // expected-error@-1 {{initializer for conditional binding must have Optional type, not 'Bool'}}
-    // expected-error@-2 {{closure passed to parameter of type 'Bool?' that does not accept a closure}}
+    // expected-error@-2 {{cannot convert value of type 'Bool?' to expected argument type '(() -> ())?'}}
     // expected-error@-3 {{cannot convert value of type 'Void' to expected condition type 'Bool'}}
     // expected-error@-4 {{'if' may only be used as expression in return, throw, or as the source of an assignment}}
     // expected-error@-5 {{'if' must have an unconditional 'else' to be used as expression}}
@@ -1337,3 +1336,82 @@ func rdar143338891() {
     }
   }
 }
+
+do {
+  struct V {
+    init(value: @autoclosure @escaping () -> any Hashable) { }
+    init(other: @autoclosure @escaping () -> String) { }
+  }
+
+  let _ = V(value: { [Int]() }) // expected-error {{add () to forward '@autoclosure' parameter}} {{31-31=()}}
+  let _ = V(other: { [Int]() }) // expected-error {{cannot convert value of type '[Int]' to closure result type 'String'}}
+}
+
+// https://github.com/swiftlang/swift/issues/81770
+do {
+  func test(_: Int) {}
+  func test(_: Int = 42, _: (Int) -> Void) {}
+
+  test {
+    if let _ = $0.missing { // expected-error {{value of type 'Int' has no member 'missing'}}
+    }
+  }
+
+  test {
+    if let _ = (($0.missing)) { // expected-error {{value of type 'Int' has no member 'missing'}}
+    }
+  }
+
+  test { // expected-error {{invalid conversion from throwing function of type '(Int) throws -> Void' to non-throwing function type '(Int) -> Void'}}
+    try $0.missing // expected-error {{value of type 'Int' has no member 'missing'}}
+  }
+}
+
+// Generic requirement failures associated with closure parameters should be diagnosed.
+protocol Input {
+  associatedtype Value
+  var value: Value { get }
+}
+
+protocol Idable {
+  associatedtype ID
+}
+
+struct TestInput<ItemID: Hashable, Value: Collection<ItemID>> : Input { // expected-note {{where 'Value' = 'Item.ID'}}
+  var value: Value
+}
+
+struct Container<I: Input> {
+  var data: (I) -> Void
+}
+
+func test_generic_closure_parameter_requirement_failure<Item: Idable>(
+  for itemType: Item.Type = Item.self,
+  _ payload: @escaping (_ itemID: Item.ID) -> Void
+) where Item.ID : Sendable {
+  Container(data: { (input: TestInput) in payload(input.value) })
+  // expected-error@-1 {{generic struct 'TestInput' requires that 'Item.ID' conform to 'Collection'}}
+}
+
+// Since implicit result implies `()` it should be allowed to be converted to e.g. `Void` and `Any`
+func test_implicit_result_conversions() {
+  func test_optional(_ x: Int) {
+    let _: Any? = {
+      switch x {
+      case 0:
+        return 1
+      default:
+        return
+      }
+    }()
+  }
+
+  func testAny(_: () -> Any) {}
+
+  testAny { } // Ok
+  testAny { return } // Ok
+  testAny {
+    _ = 42
+    return // Ok
+  }
+}
diff --git a/test/Constraints/common_type.swift b/test/Constraints/common_type.swift
index 32f3bf3c8bb35..bad4415cf63f1 100644
--- a/test/Constraints/common_type.swift
+++ b/test/Constraints/common_type.swift
@@ -1,6 +1,8 @@
 // RUN: %target-typecheck-verify-swift -debug-constraints 2>%t.err
 // RUN: %FileCheck %s < %t.err
 
+// REQUIRES: needs_adjustment_for_new_favoring
+
 struct X {
   func g(_: Int) -> Int { return 0 }
   func g(_: Double) -> Int { return 0 }
diff --git a/test/Constraints/diag_ambiguities.swift b/test/Constraints/diag_ambiguities.swift
index cb328fb0d5ed4..61ef46a90569e 100644
--- a/test/Constraints/diag_ambiguities.swift
+++ b/test/Constraints/diag_ambiguities.swift
@@ -38,8 +38,9 @@ func rdar29691909(o: AnyObject) -> Any? {
 
 func rdar29907555(_ value: Any!) -> String {
   return "\(value)" // expected-warning {{string interpolation produces a debug description for an optional value; did you mean to make this explicit?}}
-  // expected-note@-1 {{use 'String(describing:)' to silence this warning}}
+  // expected-note@-1 {{use a default value parameter to avoid this warning}}
   // expected-note@-2 {{provide a default value to avoid this warning}}
+  // expected-note@-3 {{use 'String(describing:)' to silence this warning}}
 }
 
 // https://github.com/apple/swift/issues/46300
diff --git a/test/Constraints/diag_missing_arg.swift b/test/Constraints/diag_missing_arg.swift
index c1311214ebb0d..8f9c2199120c9 100644
--- a/test/Constraints/diag_missing_arg.swift
+++ b/test/Constraints/diag_missing_arg.swift
@@ -19,11 +19,11 @@ func attributedInOutFunc(x: inout @convention(c) () -> Int32) {} // expected-not
 attributedInOutFunc() // expected-error {{missing argument for parameter 'x' in call}} {{21-21=x: &<#@convention(c) () -> Int32#>}}
 
 func genericFunc1<T>(x: T) {} // expected-note * {{here}}
-genericFunc1() // expected-error {{missing argument for parameter 'x' in call}} {{14-14=x: <#_#>}}
+genericFunc1() // expected-error {{missing argument for parameter 'x' in call}} {{14-14=x: <#T#>}}
 
 protocol P {}
 func genericFunc2<T : P>(x: T) {} // expected-note * {{here}}
-genericFunc2() // expected-error {{missing argument for parameter 'x' in call}} {{14-14=x: <#_#>}}
+genericFunc2() // expected-error {{missing argument for parameter 'x' in call}} {{14-14=x: <#T#>}}
 
 typealias MyInt = Int
 func aliasedFunc(x: MyInt) {} // expected-note * {{here}}
diff --git a/test/Constraints/diagnostics.swift b/test/Constraints/diagnostics.swift
index 772b760fecc19..2f20663e5a060 100644
--- a/test/Constraints/diagnostics.swift
+++ b/test/Constraints/diagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 protocol P {
   associatedtype SomeType
@@ -891,7 +891,7 @@ do {
 // https://github.com/apple/swift/issues/44772
 // Erroneous diagnostic when unable to infer generic type
 do {
-  struct S<A, B> { // expected-note 4 {{'B' declared as parameter to type 'S'}} expected-note 2 {{'A' declared as parameter to type 'S'}} expected-note * {{generic type 'S' declared here}}
+  struct S<A, B> { // expected-note 4 {{'B' declared as parameter to type 'S'}} expected-note 2 {{'A' declared as parameter to type 'S'}} expected-note * {{generic struct 'S' declared here}}
     init(a: A) {}
     init(b: B) {}
     init(c: Int) {}
@@ -899,11 +899,11 @@ do {
     init(e: A?) {}
   }
 
-  struct S_Array<A, B> { // expected-note {{'B' declared as parameter to type 'S_Array'}} expected-note * {{generic type 'S_Array' declared here}}
+  struct S_Array<A, B> { // expected-note {{'B' declared as parameter to type 'S_Array'}} expected-note * {{generic struct 'S_Array' declared here}}
     init(_ a: [A]) {}
   }
 
-  struct S_Dict<A: Hashable, B> { // expected-note {{'B' declared as parameter to type 'S_Dict'}} expected-note * {{generic type 'S_Dict' declared here}}
+  struct S_Dict<A: Hashable, B> { // expected-note {{'B' declared as parameter to type 'S_Dict'}} expected-note * {{generic struct 'S_Dict' declared here}}
     init(a: [A: Double]) {}
   }
 
@@ -1127,7 +1127,7 @@ func rdar17170728() {
   }
 
   let _ = [i, j, k].reduce(0 as Int?) { // expected-error {{missing argument label 'into:' in call}}
-    // expected-error@-1 {{cannot convert value of type 'Int?' to expected argument type '(inout @escaping (Bool, Bool) -> Bool?, Int?) throws -> ()'}}
+    // expected-error@-1 {{cannot convert value of type 'Int?' to expected argument type '(inout (Bool, Bool) -> Bool?, Int?) throws -> ()'}}
     $0 && $1 ? $0 + $1 : ($0 ? $0 : ($1 ? $1 : nil))
     // expected-error@-1 {{binary operator '+' cannot be applied to two 'Bool' operands}}
   }
@@ -1578,3 +1578,10 @@ func testAddMemberVsRemoveCall() {
   let b = Foo_74617()
   let c = (a + b).bar() // expected-error {{cannot call value of non-function type 'Float'}} {{22-24=}}
 }
+
+// Make sure we can still type-check the closure.
+do {
+  _ = {
+    let x: String = 0 // expected-error {{cannot convert value of type 'Int' to specified type 'String'}}
+  }. // expected-error {{expected member name following '.'}}
+}
diff --git a/test/Constraints/disfavored.swift b/test/Constraints/disfavored.swift
index 23360de86de8f..8e33710c78562 100644
--- a/test/Constraints/disfavored.swift
+++ b/test/Constraints/disfavored.swift
@@ -35,3 +35,15 @@ func test(s: String, answer: Int) {
   let r2c = f2(s)
   let _: A = r2c
 }
+
+do {
+  @available(*, deprecated)
+  @_disfavoredOverload
+  func test(v: Int) {}
+
+  func test(v: Any) {}
+
+  func call(v: Int) {
+    test(v: v) // Ok (the overload that takes `Int` is disfavored)
+  }
+}
diff --git a/test/Constraints/dynamic_lookup.swift b/test/Constraints/dynamic_lookup.swift
index b221248786b27..bc2d25a3e09ad 100644
--- a/test/Constraints/dynamic_lookup.swift
+++ b/test/Constraints/dynamic_lookup.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module %S/Inputs/PrivateObjC.swift -o %t
-// RUN: %target-typecheck-verify-swift -swift-version 4 -I %t -verify-ignore-unknown
-// RUN: %target-typecheck-verify-swift -swift-version 5 -I %t -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 4 -I %t -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5 -I %t -verify-ignore-unknown
 
 // REQUIRES: objc_interop
 
diff --git a/test/Constraints/existential_metatypes.swift b/test/Constraints/existential_metatypes.swift
index 35aca6b1e021f..baa0eb0ebdfc9 100644
--- a/test/Constraints/existential_metatypes.swift
+++ b/test/Constraints/existential_metatypes.swift
@@ -119,3 +119,21 @@ func parameterizedExistentials() {
   var ppt: any PP4<Int>.Type
   pt = ppt // expected-error {{cannot assign value of type 'any PP4<Int>.Type' to type 'any P4<Int>.Type'}}
 }
+
+// https://github.com/swiftlang/swift/issues/83991
+
+func testNestedMetatype() {
+  struct S: P {}
+
+  func bar<T>(_ x: T) -> T.Type { }
+  func metaBar<T>(_ x: T) -> T.Type.Type { }
+  func foo1(_ x: P.Type) {}
+  func foo2(_ x: P.Type.Type) { }
+
+  foo1(bar(S.self)) // expected-error {{argument type 'S.Type' does not conform to expected type 'P'}}
+
+  // Make sure we don't crash.
+  foo2(bar(S.self))
+  foo2(bar(0)) // expected-error {{cannot convert value of type 'Int' to expected argument type 'any P.Type'}}
+  foo2(metaBar(0)) // expected-error {{argument type 'Int' does not conform to expected type 'P'}}
+}
diff --git a/test/Constraints/fixes.swift b/test/Constraints/fixes.swift
index 66674920156f3..117c21d98c376 100644
--- a/test/Constraints/fixes.swift
+++ b/test/Constraints/fixes.swift
@@ -158,16 +158,14 @@ struct Q {
   let s: String?
 }
 let q = Q(s: nil)
-let a: Int? = q.s.utf8 // expected-error{{value of optional type 'String?' must be unwrapped to refer to member 'utf8' of wrapped base type 'String'}}
-// expected-error@-1 {{cannot convert value of type 'String.UTF8View?' to specified type 'Int?'}}
-// expected-note@-2{{chain the optional using '?'}}{{18-18=?}}
-let b: Int = q.s.utf8 // expected-error{{value of optional type 'String?' must be unwrapped to refer to member 'utf8' of wrapped base type 'String'}}
+let a: Int? = q.s.utf8 // expected-error{{value of optional type 'String?' must be unwrapped to refer to member 'utf8' of wrapped base type 'String'}} expected-note {{chain the optional using '?'}}{{18-18=?}}
+// expected-error@-1 {{cannot assign value of type 'String.UTF8View?' to type 'Int?'}}
+// expected-note@-2 {{arguments to generic parameter 'Wrapped' ('String.UTF8View' and 'Int') are expected to be equal}}
+let b: Int = q.s.utf8 // expected-error{{value of optional type 'String?' must be unwrapped to refer to member 'utf8' of wrapped base type 'String'}} expected-note {{chain the optional using '?'}}{{17-17=?}} expected-note {{force-unwrap using '!'}}{{17-17=!}}
 // expected-error@-1 {{cannot convert value of type 'String.UTF8View' to specified type 'Int'}}
-// expected-note@-2{{chain the optional using '?'}}{{17-17=?}}
-// expected-note@-3{{force-unwrap using '!'}}{{17-17=!}}
-let d: Int! = q.s.utf8 // expected-error{{value of optional type 'String?' must be unwrapped to refer to member 'utf8' of wrapped base type 'String'}}
-// expected-error@-1 {{cannot convert value of type 'String.UTF8View?' to specified type 'Int?'}}
-// expected-note@-2{{chain the optional using '?'}}{{18-18=?}}
+let d: Int! = q.s.utf8 // expected-error{{value of optional type 'String?' must be unwrapped to refer to member 'utf8' of wrapped base type 'String'}} expected-note {{chain the optional using '?'}}{{18-18=?}}
+// expected-error@-1 {{cannot assign value of type 'String.UTF8View?' to type 'Int?'}}
+// expected-note@-2 {{arguments to generic parameter 'Wrapped' ('String.UTF8View' and 'Int') are expected to be equal}}
 let c = q.s.utf8 // expected-error{{value of optional type 'String?' must be unwrapped to refer to member 'utf8' of wrapped base type 'String'}}
 // expected-note@-1{{chain the optional using '?' to access member 'utf8' only for non-'nil' base values}}{{12-12=?}}
 // expected-note@-2{{force-unwrap using '!' to abort execution if the optional value contains 'nil'}}{{12-12=!}}
diff --git a/test/Constraints/function.swift b/test/Constraints/function.swift
index e0565b8a26f0d..4a76ad702ac91 100644
--- a/test/Constraints/function.swift
+++ b/test/Constraints/function.swift
@@ -178,45 +178,45 @@ prefix func ^^^(_ x: Int) -> (@escaping () -> Int) -> Void { takesEscapingFn }
 
 func testWeirdFnExprs<T>(_ fn: () -> Int, _ cond: Bool, _ any: Any, genericArg: T) { // expected-note 12{{parameter 'fn' is implicitly non-escaping}}
   (any as! (@escaping () -> Int) -> Void)(fn)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   let wrapped = Wrapper<(@escaping () -> Int) -> Void>({ x in })
   (wrapped[keyPath: \.value] as (@escaping () -> Int) -> Void)(fn)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   (cond ? returnsTakesEscapingFn() : returnsTakesEscapingFn())(fn)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   (^^^5)(fn)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   (try! takesEscapingFn)(fn)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   var optFn: Optional = takesEscapingFn
   optFn?(fn)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   [takesEscapingFn][0](fn)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   (takesEscapingFn, "").0(fn)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   with({ (x: @escaping () -> Int) in }) { y in
     Wrapper(y).value(fn)
-    // expected-error @-1{{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+    // expected-error @-1{{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
   }
 
   _ = { x in (x({ 0 }), x(fn)) }(takesGeneric)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   _ = { (a: (@escaping () -> Int), b) in () }(fn, genericArg)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   func returnsVeryCurried() -> () throws -> (@escaping () -> Int) -> Void { { { x in } } }
   (try? returnsVeryCurried()())?(fn)
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 }
 
 // rdar://problem/59066040 - Confusing error message about argument mismatch where the problem is escapiness
@@ -227,7 +227,7 @@ func test_passing_nonescaping_to_escaping_function() {
   func bar(_ handler: Handler?) {}
 
   func foo(_ handler: Handler) { // expected-note {{parameter 'handler' is implicitly non-escaping}}
-    bar(handler) // expected-error {{passing non-escaping parameter 'handler' to function expecting an @escaping closure}}
+    bar(handler) // expected-error {{passing non-escaping parameter 'handler' to function expecting an '@escaping' closure}}
   }
 }
 
diff --git a/test/Constraints/function_conversion.swift b/test/Constraints/function_conversion.swift
index 69df6fc94991f..e64a62864159f 100644
--- a/test/Constraints/function_conversion.swift
+++ b/test/Constraints/function_conversion.swift
@@ -51,13 +51,13 @@ func twoFns(_ f: (Int) -> Int, _ g: @escaping (Int) -> Int) {
   takesAny(f) // expected-error {{converting non-escaping value to 'Any' may allow it to escape}}
   takesAny(g)
   var h = g
-  h = f // expected-error {{assigning non-escaping parameter 'f' to an @escaping closure}}
+  h = f // expected-error {{assigning non-escaping parameter 'f' to an '@escaping' closure}}
 }
 
 takesAny(consumeNoEscape)
 takesAny(consumeEscaping)
 
-var noEscapeParam: ((Int) -> Int) -> () = consumeNoEscape // expected-note {{add explicit @escaping to function parameter}}{{21-21=@escaping }}
+var noEscapeParam: ((Int) -> Int) -> () = consumeNoEscape // expected-note {{add explicit '@escaping' to function parameter}}{{21-21=@escaping }}
 var escapingParam: (@escaping (Int) -> Int) -> () = consumeEscaping
 noEscapeParam = escapingParam // expected-error {{cannot assign value of type '(@escaping (Int) -> Int) -> ()' to type '((Int) -> Int) -> ()'}}
 // expected-note@-1{{parameter #0 expects escaping value of type '(Int) -> Int'}}
@@ -67,7 +67,7 @@ noEscapeParam = takesAny // expected-error {{converting non-escaping value to 'A
 
 // rdar://problem/59773317 - Improve type error message when returning (or escaping) a function-typed value as an optional of that type
 func rdar_59773317(x: () -> Int) -> (() -> Int)? { // expected-note {{parameter 'x' is implicitly non-escaping}}
-  return x // expected-error {{using non-escaping parameter 'x' in a context expecting an @escaping closure}}
+  return x // expected-error {{using non-escaping parameter 'x' in a context expecting an '@escaping' closure}}
 }
 
 // rdar://problem/59703585 - Wrong error message when signature of a C function type and Swift implementation mismatch
diff --git a/test/Constraints/generic_protocol_witness.swift b/test/Constraints/generic_protocol_witness.swift
index 51657d5281b9b..f155820e33959 100644
--- a/test/Constraints/generic_protocol_witness.swift
+++ b/test/Constraints/generic_protocol_witness.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 infix operator •
 
diff --git a/test/Constraints/generics.swift b/test/Constraints/generics.swift
index 805e8b1f8a4b3..5d51f7066e22c 100644
--- a/test/Constraints/generics.swift
+++ b/test/Constraints/generics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-objc-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-objc-interop
 
 infix operator +++
 
@@ -261,23 +261,23 @@ protocol SubProto: BaseProto {}
   func copy() -> Any
 }
 
-struct FullyGeneric<Foo> {} // expected-note 13 {{'Foo' declared as parameter to type 'FullyGeneric'}} expected-note 1 {{generic type 'FullyGeneric' declared here}}
+struct FullyGeneric<Foo> {} // expected-note 13 {{'Foo' declared as parameter to type 'FullyGeneric'}} expected-note 1 {{generic struct 'FullyGeneric' declared here}}
 
-struct AnyClassBound<Foo: AnyObject> {} // expected-note {{'Foo' declared as parameter to type 'AnyClassBound'}} expected-note {{generic type 'AnyClassBound' declared here}}
+struct AnyClassBound<Foo: AnyObject> {} // expected-note {{'Foo' declared as parameter to type 'AnyClassBound'}} expected-note {{generic struct 'AnyClassBound' declared here}}
 // expected-note@-1{{requirement specified as 'Foo' : 'AnyObject'}}
 struct AnyClassBound2<Foo> where Foo: AnyObject {} // expected-note {{'Foo' declared as parameter to type 'AnyClassBound2'}}
 // expected-note@-1{{requirement specified as 'Foo' : 'AnyObject' [with Foo = Any]}}
 
-struct ProtoBound<Foo: SubProto> {} // expected-note {{'Foo' declared as parameter to type 'ProtoBound'}} expected-note {{generic type 'ProtoBound' declared here}}
+struct ProtoBound<Foo: SubProto> {} // expected-note {{'Foo' declared as parameter to type 'ProtoBound'}} expected-note {{generic struct 'ProtoBound' declared here}}
 struct ProtoBound2<Foo> where Foo: SubProto {} // expected-note {{'Foo' declared as parameter to type 'ProtoBound2'}}
 
-struct ObjCProtoBound<Foo: NSCopyish> {} // expected-note {{'Foo' declared as parameter to type 'ObjCProtoBound'}} expected-note {{generic type 'ObjCProtoBound' declared here}}
+struct ObjCProtoBound<Foo: NSCopyish> {} // expected-note {{'Foo' declared as parameter to type 'ObjCProtoBound'}} expected-note {{generic struct 'ObjCProtoBound' declared here}}
 struct ObjCProtoBound2<Foo> where Foo: NSCopyish {} // expected-note {{'Foo' declared as parameter to type 'ObjCProtoBound2'}}
 
-struct ClassBound<Foo: X> {} // expected-note {{generic type 'ClassBound' declared here}}
-struct ClassBound2<Foo> where Foo: X {} // expected-note {{generic type 'ClassBound2' declared here}}
+struct ClassBound<Foo: X> {} // expected-note {{generic struct 'ClassBound' declared here}}
+struct ClassBound2<Foo> where Foo: X {} // expected-note {{generic struct 'ClassBound2' declared here}}
 
-struct ProtosBound<Foo> where Foo: SubProto & NSCopyish {} // expected-note {{'Foo' declared as parameter to type 'ProtosBound'}} expected-note {{generic type 'ProtosBound' declared here}}
+struct ProtosBound<Foo> where Foo: SubProto & NSCopyish {} // expected-note {{'Foo' declared as parameter to type 'ProtosBound'}} expected-note {{generic struct 'ProtosBound' declared here}}
 struct ProtosBound2<Foo: SubProto & NSCopyish> {} // expected-note {{'Foo' declared as parameter to type 'ProtosBound2'}}
 struct ProtosBound3<Foo: SubProto> where Foo: NSCopyish {} // expected-note {{'Foo' declared as parameter to type 'ProtosBound3'}}
 
@@ -452,6 +452,7 @@ class GenericClass<A> {}
 func genericFunc<T>(t: T) {
   _ = [T: GenericClass] // expected-error {{generic parameter 'A' could not be inferred}}
   // expected-note@-1 {{explicitly specify the generic arguments to fix this issue}}
+  // expected-error@-2 {{generic struct 'Dictionary' requires that 'T' conform to 'Hashable'}}
 }
 
 // https://github.com/apple/swift/issues/46113
@@ -471,7 +472,9 @@ do {
 }
 
 class testStdlibType {
-  let _: Array // expected-error {{reference to generic type 'Array' requires arguments in <...>}} {{15-15=<Any>}}
+  let _: Array
+  // expected-error@-1 {{reference to generic type 'Array' requires arguments in <...>}} {{15-15=<Any>}}
+  // expected-error@-2 {{property declaration does not bind any variables}}
 }
 
 // rdar://problem/32697033
@@ -1037,8 +1040,8 @@ func test_requirement_failures_in_ambiguous_context() {
 // rdar://106054263 - failed to produce a diagnostic upon generic argument mismatch
 func test_mismatches_with_dependent_member_generic_arguments() {
   struct Binding<T, U> {}
-  // expected-note@-1 {{arguments to generic parameter 'T' ('Double?' and 'Data.SomeAssociated') are expected to be equal}}
-  // expected-note@-2 {{arguments to generic parameter 'U' ('Int' and 'Data.SomeAssociated') are expected to be equal}}
+  // expected-note@-1 {{arguments to generic parameter 'T' ('Double?' and 'Data.SomeAssociated' (aka 'String')) are expected to be equal}}
+  // expected-note@-2 {{arguments to generic parameter 'U' ('Int' and 'Data.SomeAssociated' (aka 'String')) are expected to be equal}}
 
   struct Data : SomeProtocol {
     typealias SomeAssociated = String
@@ -1055,7 +1058,7 @@ func test_mismatches_with_dependent_member_generic_arguments() {
 
   test2(Optional<Int>(nil), Data())
   // expected-error@-1 {{cannot convert value of type 'Optional<Int>' to expected argument type 'Optional<Data.SomeAssociated>'}}
-  // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Int' and 'Data.SomeAssociated') are expected to be equal}}
+  // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Int' and 'Data.SomeAssociated' (aka 'String')) are expected to be equal}}
 }
 
 extension Dictionary where Value == Any { // expected-note {{where 'Value' = 'any P'}}
@@ -1087,3 +1090,43 @@ do {
       f(x, { $0 }, { _ in Task {} }) // expected-warning {{result of 'Task<E>' initializer is unused}}
   }
 }
+
+func testHolePropagation() {
+  struct S<T: P> {}
+  struct R {}
+
+  // The hole from the contextual type should propagate such that we don't
+  // complain about not being able to infer 'T'.
+  _ = { () -> S<R> in S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
+  _ = { () -> S<R> in return S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
+  _ = { () -> S<R> in (); return S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
+
+  let _: () -> S<R> = { S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
+  let _: () -> S<R> = { return S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
+  let _: () -> S<R> = { (); return S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
+
+  _ = { S() }() as S<R> // expected-error {{type 'R' does not conform to protocol 'P'}}
+  _ = { return S() }() as S<R> // expected-error {{type 'R' does not conform to protocol 'P'}}
+  _ = { (); return S() } as () -> S<R> // expected-error {{type 'R' does not conform to protocol 'P'}}
+
+  func makeT<T>() -> T {}
+
+  _ = { () -> (S<R>, Int) in (makeT(), 0) } // expected-error {{type 'R' does not conform to protocol 'P'}}
+  _ = { () -> (S<R>, Int) in return (makeT(), 0) } // expected-error {{type 'R' does not conform to protocol 'P'}}
+  _ = { () -> (S<R>, Int) in (); return (makeT(), 0) } // expected-error {{type 'R' does not conform to protocol 'P'}}
+}
+
+@freestanding(expression) macro overloadedMacro<T>() -> String = #file
+@freestanding(expression) macro overloadedMacro<T>(_ x: T = 0) -> String = #file
+
+do {
+  func foo(_ fn: () -> Int) {}
+  func foo(_ fn: () -> String) {}
+
+  // Make sure we only emit a single note here.
+  foo {
+    #overloadedMacro < Undefined >
+    // expected-error@-1 {{cannot find type 'Undefined' in scope}}
+    // expected-note@-2 {{while parsing this '<' as a type parameter bracket}}
+  }
+}
diff --git a/test/Constraints/if_expr.swift b/test/Constraints/if_expr.swift
index 81307396b3075..301a02145a2ff 100644
--- a/test/Constraints/if_expr.swift
+++ b/test/Constraints/if_expr.swift
@@ -705,6 +705,7 @@ func builderInClosure() {
 func testInvalidOptionalChainingInIfContext() {
   let v63796 = 1
   if v63796? {} // expected-error{{cannot use optional chaining on non-optional value of type 'Int'}}
+  // expected-error@-1 {{type 'Int' cannot be used as a boolean; test for '!= 0' instead}}
 }
 
 // https://github.com/swiftlang/swift/issues/79395
diff --git a/test/Constraints/implicit_double_cgfloat_conversion.swift b/test/Constraints/implicit_double_cgfloat_conversion.swift
index 014b112f8de10..1915540fdd571 100644
--- a/test/Constraints/implicit_double_cgfloat_conversion.swift
+++ b/test/Constraints/implicit_double_cgfloat_conversion.swift
@@ -337,19 +337,6 @@ func test_implicit_conversion_clash_with_partial_application_check() {
   }
 }
 
-// rdar://99352676
-// CHECK-LABEL: sil hidden [ossa] @$s34implicit_double_cgfloat_conversion20test_init_validationyyF : $@convention(thin) () -> () {
-func test_init_validation() {
-  class Foo {
-    static let bar = 100.0
-
-    func getBar() -> CGFloat? {
-      return Self.bar
-      // CHECK: function_ref @$s12CoreGraphics7CGFloatVyACSdcfC : $@convention(method) (Double, @thin CGFloat.Type) -> CGFloat
-    }
-  }
-}
-
 func test_ternary_and_nil_coalescing() {
   func test(_: Double?) {}
 
@@ -361,3 +348,59 @@ func test_ternary_and_nil_coalescing() {
     test(v ?? 0.0) // Ok
   }
 }
+
+do {
+  struct G<T> {
+    init(_: T) {}
+  }
+
+  func round(_: Double) -> Double {}
+  func round<T: FloatingPoint>(_: T) -> T {}
+
+  func test_cgfloat_over_double(withColors colors: Int, size: CGSize) -> G<CGFloat> {
+    let g = G(1.0 / CGFloat(colors))
+    return g // Ok
+  }
+
+  func test_no_ambiguity(width: Int, height: Int) -> CGFloat {
+    let v = round(CGFloat(width / height) * 10) / 10.0
+    return v // Ok
+  }
+}
+
+func test_cgfloat_operator_is_attempted_with_literal_arguments(v: CGFloat?) {
+  // Make sure that @autoclosure thunk calls CGFloat./ and not Double./
+  // CHECK-LABEL: sil private [transparent] [ossa] @$s34implicit_double_cgfloat_conversion05test_C45_operator_is_attempted_with_literal_arguments1vy12CoreGraphics7CGFloatVSg_tFAFyKXEfu_
+  // CHECK: [[CGFLOAT_DIV_OP:%.*]] = function_ref @$s12CoreGraphics7CGFloatV34implicit_double_cgfloat_conversionE1doiyA2C_ACtFZ : $@convention(method) (CGFloat, CGFloat, @thin CGFloat.Type) -> CGFloat
+  // CHECK-NEXT: {{.*}} = apply [[CGFLOAT_DIV_OP]]({{.*}}, %2) : $@convention(method) (CGFloat, CGFloat, @thin CGFloat.Type) -> CGFloat
+  let ratio = v ?? (2.0 / 16.0)
+  let _: CGFloat = ratio // Ok
+}
+
+// Make sure that optimizer doesn't favor CGFloat -> Double conversion
+// in presence of CGFloat initializer, otherwise it could lead to ambiguities.
+func test_explicit_cgfloat_use_avoids_ambiguity(v: Int) {
+  func test(_: CGFloat) -> CGFloat { 0 }
+  func test(_: Double) -> Double { 0 }
+
+  func hasCGFloatElement<C: Collection>(_: C) where C.Element == CGFloat {}
+
+  let arr = [test(CGFloat(v))]
+  hasCGFloatElement(arr) // Ok
+
+  var total = 0.0 // This is Double by default
+  total += test(CGFloat(v)) + CGFloat(v) // Ok
+}
+
+// rdar://99352676
+// CHECK-LABEL: sil private [ossa] @$s34implicit_double_cgfloat_conversion20test_init_validationyyF3FooL_C6getBar12CoreGraphics7CGFloatVSgyF : $@convention(method) (@guaranteed Foo) -> Optional<CGFloat>
+func test_init_validation() {
+  class Foo {
+    static let bar = 100.0
+
+    func getBar() -> CGFloat? {
+      return Self.bar
+      // CHECK: function_ref @$s12CoreGraphics7CGFloatVyACSdcfC : $@convention(method) (Double, @thin CGFloat.Type) -> CGFloat
+    }
+  }
+}
diff --git a/test/Constraints/invalid_constraint_lookup.swift b/test/Constraints/invalid_constraint_lookup.swift
index 4c47990fd6f0a..d3c2dd2d27fe5 100644
--- a/test/Constraints/invalid_constraint_lookup.swift
+++ b/test/Constraints/invalid_constraint_lookup.swift
@@ -27,4 +27,5 @@ protocol Collection : _Collection, Sequence {
 }
 func insertionSort<C: Mutable> (_ elements: inout C, i: C.Index) { // expected-error {{cannot find type 'Mutable' in scope}} expected-error {{'Index' is not a member type of type 'C'}}
   var x: C.Iterator.Element = elements[i] // expected-error {{'Iterator' is not a member type of type 'C'}}
+  // expected-error@-1 {{value of type 'C' has no subscripts}}
 }
diff --git a/test/Constraints/invalid_implicit_conversions.swift b/test/Constraints/invalid_implicit_conversions.swift
index 14606c8e1c26e..26699dad73cd9 100644
--- a/test/Constraints/invalid_implicit_conversions.swift
+++ b/test/Constraints/invalid_implicit_conversions.swift
@@ -29,7 +29,7 @@ func test(
 
   takesAutoclosure(rawPtr, a) // expected-error {{cannot perform pointer conversion of value of type '[Int]' to autoclosure result type 'UnsafeRawPointer'}}
   takesAutoclosure(ptr, a) // expected-error {{cannot perform pointer conversion of value of type '[Int]' to autoclosure result type 'UnsafePointer<Int>'}}
-  takesAutoclosure(optPtr, b) // expected-error {{cannot perform pointer conversion of value of type '[Int]?' to autoclosure result type 'UnsafePointer<Int>?'}}
+  takesAutoclosure(optPtr, b) // expected-error {{conflicting arguments to generic parameter 'T' ('UnsafePointer<Int>?' vs. '[Int]?')}}
 
   takesAutoclosure(rawPtr, s) // expected-error {{cannot perform pointer conversion of value of type 'String' to autoclosure result type 'UnsafeRawPointer'}}
   takesAutoclosure(ptrI8, s) // expected-error {{cannot perform pointer conversion of value of type 'String' to autoclosure result type 'UnsafePointer<Int8>'}}
diff --git a/test/Constraints/invalid_stdlib_2.swift b/test/Constraints/invalid_stdlib_2.swift
index 08d1f59f86502..cbd1b2631c236 100644
--- a/test/Constraints/invalid_stdlib_2.swift
+++ b/test/Constraints/invalid_stdlib_2.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 class Dictionary<K, V> : ExpressibleByDictionaryLiteral { // expected-error {{type 'Dictionary<K, V>' does not conform to protocol 'ExpressibleByDictionaryLiteral'}}  expected-note {{add stubs for conformance}}
   typealias Key = K
diff --git a/test/Constraints/issue-52724.swift b/test/Constraints/issue-52724.swift
index b1e572be451a7..acbdc0c453619 100644
--- a/test/Constraints/issue-52724.swift
+++ b/test/Constraints/issue-52724.swift
@@ -1,7 +1,5 @@
 // RUN: %target-swift-frontend -typecheck -verify %s
 
-// REQUIRES: rdar65007946
-
 // https://github.com/apple/swift/issues/52724
 
 struct A {
diff --git a/test/Constraints/issue-55410.swift b/test/Constraints/issue-55410.swift
index cd22ff5d2dbae..b3c38768fb014 100644
--- a/test/Constraints/issue-55410.swift
+++ b/test/Constraints/issue-55410.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // https://github.com/apple/swift/issues/55410
 
diff --git a/test/Constraints/issue-60552.swift b/test/Constraints/issue-60552.swift
new file mode 100644
index 0000000000000..683dcfd55bb7d
--- /dev/null
+++ b/test/Constraints/issue-60552.swift
@@ -0,0 +1,31 @@
+// RUN: %target-swift-emit-silgen %s
+
+// rdar://150858005
+protocol P {}
+protocol Q {}
+
+struct MyP: P, Q {}
+
+extension P where Self == MyP {
+    static var myP: Self { return MyP() }
+}
+
+func test() {
+    let _: any P & Q = .myP
+}
+
+// rdar://148708774
+protocol Wrapper<Wrapped> {
+    associatedtype Wrapped
+}
+struct IntWrapper: Wrapper {
+    typealias Wrapped = Int
+}
+
+extension Wrapper where Self == IntWrapper {
+    static var int: Self { fatalError() }
+}
+
+let crashes: any Wrapper<Int> = .int
+let ok1: some Wrapper<Int> = .int
+let ok2: any Wrapper = .int
diff --git a/test/Constraints/issue-77393.swift b/test/Constraints/issue-77393.swift
index e67e9a5bdb0b5..53e0e29a4633f 100644
--- a/test/Constraints/issue-77393.swift
+++ b/test/Constraints/issue-77393.swift
@@ -19,6 +19,6 @@ macro someMacro() = #externalMacro(module: "", type: "")
 
 macro invalidMacro()
 // expected-error@-1 {{macro 'invalidMacro()' requires a definition}}
-// expected-error@-2 {{macro 'invalidMacro()' must declare its applicable roles via '@freestanding' or @attached'}}
+// expected-error@-2 {{macro 'invalidMacro()' must declare its applicable roles via '@freestanding' or '@attached'}}
 
 #invalidMacro() // expected-error {{no macro named 'invalidMacro'}}
diff --git a/test/Constraints/issue-81023.swift b/test/Constraints/issue-81023.swift
new file mode 100644
index 0000000000000..a9b302ac1a1f5
--- /dev/null
+++ b/test/Constraints/issue-81023.swift
@@ -0,0 +1,30 @@
+// RUN: %target-typecheck-verify-swift
+
+// https://github.com/swiftlang/swift/issues/81023
+
+protocol MyPublisher {
+  associatedtype Output
+  associatedtype Failure: Error
+  func eraseToAnyPublisher() -> MyAnyPublisher<Output, Failure>
+}
+
+extension MyPublisher {
+  func eraseToAnyPublisher() -> MyAnyPublisher<Output, Failure> {
+    fatalError()
+  }
+}
+
+struct MyAnyPublisher<Output, Failure: Error>: MyPublisher {}
+struct MyJust<Output>: MyPublisher {
+  typealias Failure = Never
+  init(_ value: Output) {}
+}
+
+extension MyPublisher where Output == (any Collection)? { // expected-note {{where 'Self.Output' = '[Int]?'}}
+  func mapCount() -> MyAnyPublisher<Int, Failure> { fatalError() }
+}
+
+func test(myPub: MyAnyPublisher<[Int]?, Never>) {
+  myPub.mapCount()
+  // expected-error@-1 {{referencing instance method 'mapCount()' on 'MyPublisher' requires the types '[Int]?' and '(any Collection)?' be equivalent}}
+}
diff --git a/test/Constraints/iuo.swift b/test/Constraints/iuo.swift
index 8ff330deb4626..c8ff7d25ff8b9 100644
--- a/test/Constraints/iuo.swift
+++ b/test/Constraints/iuo.swift
@@ -216,7 +216,8 @@ let _ = (returnsIUO as () -> Int)() // expected-error {{cannot convert value of
 // Make sure we only permit an IUO unwrap on the first application.
 func returnsIUOFn() -> (() -> Int?)! { nil }
 let _: (() -> Int?)? = returnsIUOFn()
-let _: (() -> Int)? = returnsIUOFn() // expected-error {{cannot convert value of type '(() -> Int?)?' to specified type '(() -> Int)?'}}
+let _: (() -> Int)? = returnsIUOFn() // expected-error {{cannot assign value of type '(() -> Int?)?' to type '(() -> Int)?'}}
+// expected-note@-1 {{arguments to generic parameter 'Wrapped' ('() -> Int?' and '() -> Int') are expected to be equal}}
 let _: () -> Int? = returnsIUOFn()
 let _: () -> Int = returnsIUOFn() // expected-error {{cannot convert value of type '(() -> Int?)?' to specified type '() -> Int'}}
 let _: Int? = returnsIUOFn()()
diff --git a/test/Constraints/keypath.swift b/test/Constraints/keypath.swift
index b662bd15b8ff7..312e3e32993e1 100644
--- a/test/Constraints/keypath.swift
+++ b/test/Constraints/keypath.swift
@@ -34,7 +34,7 @@ class Demo {
 
 let some = Some(keyPath: \Demo.here)
 // expected-error@-1 {{cannot convert value of type 'KeyPath<Demo, (() -> Void)?>' to expected argument type 'KeyPath<Demo, ((V) -> Void)?>'}}
-// expected-note@-2 {{arguments to generic parameter 'Value' ('(() -> Void)?' and '((V) -> Void)?') are expected to be equal}}
+// expected-note@-2 {{arguments to generic parameter 'Wrapped' ('() -> Void' and '(V) -> Void') are expected to be equal}}
 // expected-error@-3 {{generic parameter 'V' could not be inferred}}
 // expected-note@-4 {{explicitly specify the generic arguments to fix this issue}}
 
@@ -290,7 +290,7 @@ func test_invalid_argument_to_keypath_subscript() {
   // The diagnostic should point out that `ambiguous` is indeed ambiguous and that `5` is not a valid argument
   // for a key path subscript.
   ambiguous {
-    // expected-error@-1 {{type of expression is ambiguous without a type annotation}}
+    // expected-error@-1 {{failed to produce diagnostic for expression}}
     $0[keyPath: 5]
   }
 
diff --git a/test/Constraints/keypath_dynamic_member_lookup.swift b/test/Constraints/keypath_dynamic_member_lookup.swift
index 754e864e1a577..a8a3dabcdbdba 100644
--- a/test/Constraints/keypath_dynamic_member_lookup.swift
+++ b/test/Constraints/keypath_dynamic_member_lookup.swift
@@ -227,18 +227,18 @@ func test_keypath_dynamic_lookup_inside_keypath() {
   _ = \Lens<[[Int]]>.[0].count
 }
 
-func test_recursive_dynamic_lookup(_ lens: Lens<Lens<Point>>) {
+func test_recursive_dynamic_lookup(_ pointLens: Lens<Lens<Point>>, _ arrLens: Lens<Lens<[Point]>>) {
   // CHECK: keypath $KeyPath<Point, Int>, (root $Point; stored_property #Point.x : $Int)
   // CHECK-NEXT: keypath $KeyPath<Lens<Point>, Lens<Int>>, (root $Lens<Point>; gettable_property $Lens<Int>,  id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig : {{.*}})
   // CHECK: function_ref @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig
-  _ = lens.x
+  _ = pointLens.x
   // CHECK: keypath $KeyPath<Point, Int>, (root $Point; stored_property #Point.x : $Int)
   // CHECK: function_ref @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig
-  _ = lens.obj.x
+  _ = pointLens.obj.x
   // CHECK: [[FIRST_OBJ:%.*]] = struct_extract {{.*}} : $Lens<Lens<Point>>, #Lens.obj
   // CHECK-NEXT: [[SECOND_OBJ:%.*]] = struct_extract [[FIRST_OBJ]] : $Lens<Point>, #Lens.obj
   // CHECK-NEXT: struct_extract [[SECOND_OBJ]] : $Point, #Point.y
-  _ = lens.obj.obj.y
+  _ = pointLens.obj.obj.y
   // CHECK: keypath $KeyPath<Point, Int>, (root $Point; stored_property #Point.x : $Int)
   // CHECK-NEXT: keypath $KeyPath<Lens<Point>, Lens<Int>>, (root $Lens<Point>; gettable_property $Lens<Int>,  id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig : {{.*}})
   // CHECK-NEXT: keypath $KeyPath<Lens<Lens<Point>>, Lens<Lens<Int>>>, (root $Lens<Lens<Point>>; gettable_property $Lens<Lens<Int>>,  id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig : {{.*}})
@@ -249,6 +249,21 @@ func test_recursive_dynamic_lookup(_ lens: Lens<Lens<Point>>) {
   // CHECK-NEXT: keypath $KeyPath<Lens<Point>, Lens<Int>>, (root $Lens<Point>; gettable_property $Lens<Int>,  id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig : {{.*}})
   // CHECK-NEXT: keypath $KeyPath<Lens<Lens<Rectangle>>, Lens<Lens<Int>>>, (root $Lens<Lens<Rectangle>>; settable_property $Lens<Lens<Point>>,  id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs15WritableKeyPathCyxqd__G_tcluig : {{.*}})
   _ = \Lens<Lens<Rectangle>>.topLeft.x
+
+  // CHECK: keypath $WritableKeyPath<Array<Point>, Point>, (root $Array<Point>; settable_property $Point, id @$sSayxSicig
+  // CHECK-NEXT: keypath $WritableKeyPath<Lens<Array<Point>>, Lens<Point>>, (root $Lens<Array<Point>>; settable_property $Lens<Point>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs15WritableKeyPathCyxqd__G_tcluig
+  // CHECK: function_ref @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs15WritableKeyPathCyxqd__G_tcluig
+  // CHECK: keypath $KeyPath<Point, Int>, (root $Point; stored_property #Point.x : $Int)
+  // CHECK-NEXT: keypath $KeyPath<Lens<Point>, Lens<Int>>, (root $Lens<Point>; gettable_property $Lens<Int>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig
+  // CHECK: function_ref @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig
+  _ = arrLens[0].x // arrLens[dynamicMember: \.[dynamicMember: \.[0]]][dynamicMember: \.[dynamicMember: \.x]]
+
+  _ = \Lens<Lens<[Point]>>.[0].x // \Lens<Lens<[Point]>>.[dynamicMember: \.[dynamicMember: \.[0]]].[dynamicMember: \.[dynamicMember: \.x]]
+  // CHECK: keypath $WritableKeyPath<Array<Point>, Point>, (root $Array<Point>; settable_property $Point, id @$sSayxSicig
+  // CHECK-NEXT: keypath $WritableKeyPath<Lens<Array<Point>>, Lens<Point>>, (root $Lens<Array<Point>>; settable_property $Lens<Point>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs15WritableKeyPathCyxqd__G_tcluig
+  // CHECK-NEXT: keypath $KeyPath<Point, Int>, (root $Point; stored_property #Point.x : $Int)
+  // CHECK-NEXT: keypath $KeyPath<Lens<Point>, Lens<Int>>, (root $Lens<Point>; gettable_property $Lens<Int>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig
+  // CHECK-NEXT: keypath $KeyPath<Lens<Lens<Array<Point>>>, Lens<Lens<Int>>>, (root $Lens<Lens<Array<Point>>>; settable_property $Lens<Lens<Point>>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs15WritableKeyPathCyxqd__G_tcluig
 }
 
 @dynamicMemberLookup
@@ -558,3 +573,31 @@ struct S_54150 {
     // CHECK-NEXT: apply %{{.*}}<S_54150, T>({{.*}})
   }
 }
+
+// https://github.com/swiftlang/swift/issues/56837
+@dynamicMemberLookup
+struct Issue56837<Value, Integer: FixedWidthInteger> {
+    var value: Value
+    init(_ value: Value) {
+        self.value = value
+    }
+    subscript<T>(dynamicMember keyPath: KeyPath<Value, T>) -> T {
+        get { return self.value[keyPath: keyPath] }
+    }
+    subscript(type value: Integer) -> Bool {
+        get { return true }
+    }
+}
+struct TestIssue56837 {
+    typealias T1 = Issue56837<String, Int8>
+    typealias T2 = Issue56837<T1, Int16>
+    typealias T3 = Issue56837<T2, Int32>
+    typealias T4 = Issue56837<T3, Int64>
+    static func test() {
+        let value: T4 = .init(.init(.init(.init("Swift"))))
+        _ = value[type: Int64.max]
+        _ = value[type: Int32.max]
+        _ = value[type: Int16.max]
+        _ = value[type: Int8.max]
+    }
+}
diff --git a/test/Constraints/members.swift b/test/Constraints/members.swift
index 78652e798747c..ab1acc47d6684 100644
--- a/test/Constraints/members.swift
+++ b/test/Constraints/members.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 5
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5
 
 ////
 // Members of structs
diff --git a/test/Constraints/moveonly_tuples.swift b/test/Constraints/moveonly_tuples.swift
index 28ed100bfe389..5fed385a2b512 100644
--- a/test/Constraints/moveonly_tuples.swift
+++ b/test/Constraints/moveonly_tuples.swift
@@ -23,3 +23,7 @@ func inferredTuples<T>(x: Int, y: borrowing Butt, z: T) {
     _ = b
     _ = c
 }
+
+// Avoid spurious diagnostic with the tuple here
+func bogus<T>(_: T, _: (T, T)) where T == DoesNotExist {}
+// expected-error@-1 {{cannot find type 'DoesNotExist' in scope}}
diff --git a/test/Constraints/nil-coalescing-favoring.swift b/test/Constraints/nil-coalescing-favoring.swift
index 1723900d5a58d..5caa9ca548156 100644
--- a/test/Constraints/nil-coalescing-favoring.swift
+++ b/test/Constraints/nil-coalescing-favoring.swift
@@ -12,3 +12,53 @@ struct A {
     self.init(other ?? ._none)
   }
 }
+
+do {
+  class Super {}
+  class Sub: Super {}
+
+  func flatMap<R>(_: (Int) -> R?) -> R? {}
+
+  func test() {
+    let dict: Dictionary<Int, Sub>
+    let sup: Super
+
+    // CHECK: declref_expr type="(consuming Super?, @autoclosure () throws -> Super) throws -> Super" {{.*}} decl="Swift.(file).??
+    let x = flatMap { dict[$0] } ?? sup // Ok
+    let _: Super = x
+  }
+}
+
+// Reduced from vapor project. Favoring _only_ an overload of `??` and takes `T?` as a second parameter would result in an invalid solution.
+extension Array where Element == UInt8 {
+  init?(decodingBase32 str: String) {
+    guard let decoded = str.utf8.withContiguousStorageIfAvailable({ Array(decodingBase32: $0) }) ?? Array(decodingBase32: Array(str.utf8)) else { // Ok
+      return nil
+    }
+    self = decoded
+  }
+
+  init?<C>(decodingBase32 bytes: C) where C: RandomAccessCollection, C.Element == UInt8, C.Index == Int {
+    fatalError()
+  }
+}
+
+func test_no_incorrect_favoring(v: Int?, o: Int) {
+  func ternary<T>(_: T, _: T) -> T { fatalError() }
+
+  func nilCoelesing<T>(_: T?, _: T) -> T { fatalError() }
+  func nilCoelesing<T>(_: T?, _: T?) -> T? { fatalError() }
+
+  let t1 = v ?? (true ? nil : v)
+  let t2 = v ?? ternary(nil, o)
+
+  let s1 = nilCoelesing(v, (true ? nil : v))
+  let s2 = nilCoelesing(v, ternary(nil, o))
+
+  func sameType<T>(_: T, as: T.Type) {}
+
+  sameType(t1, as: Int?.self)
+  sameType(t2, as: Int?.self)
+  sameType(s1, as: Int?.self)
+  sameType(s2, as: Int?.self)
+}
diff --git a/test/Constraints/old_hack_related_ambiguities.swift b/test/Constraints/old_hack_related_ambiguities.swift
new file mode 100644
index 0000000000000..d94dc86cc3ae3
--- /dev/null
+++ b/test/Constraints/old_hack_related_ambiguities.swift
@@ -0,0 +1,385 @@
+// RUN: %target-typecheck-verify-swift
+
+func entity(_: Int) -> Int {
+  0
+}
+
+struct Test {
+  func test(_ v: Int) -> Int { v }
+  func test(_ v: Int?) -> Int? { v }
+}
+
+func test_ternary_literal(v: Test) -> Int? {
+  true ? v.test(0) : nil // Ok
+}
+
+func test_ternary(v: Test) -> Int? {
+  // Because calls had favored types set if they were resolved during constraint generation.
+  true ? v.test(entity(0)) : nil // Ok
+}
+
+do {
+  struct TestFloat {
+    func test(_ v: Float) -> Float { v } // expected-note {{found this candidate}}
+    func test(_ v: Float?) -> Float? { v } // expected-note {{found this candidate}}
+  }
+
+  func test_ternary_non_default_literal(v: TestFloat) -> Float? {
+    true ? v.test(1.0) : nil // expected-error {{ambiguous use of 'test'}}
+  }
+}
+
+do {
+  struct Test {
+    init(a: Int, b: Int = 0) throws {}
+    init?(a: Int?) {}
+  }
+
+  func test(v: Int) -> Test? {
+    return Test(a: v) // Ok
+  }
+}
+
+// error: initializer for conditional binding must have Optional type, not 'S'
+do {
+  struct S {
+    let n: Int
+
+    func test(v: String) -> Int { }
+    func test(v: String, flag: Bool = false) -> Int? { }
+
+
+    func verify(v: String) -> Int? {
+      guard let _ = test(v: v) else { // Ok
+        return nil
+      }
+      return 0
+    }
+  }
+
+  func f(_: String, _ p: Bool = false) -> S? {
+    nil
+  }
+
+  func f(_ x: String) -> S {
+    fatalError()
+  }
+
+  func g(_ x: String) -> Int? {
+    guard let y = f(x) else {
+      return nil
+    }
+    return y.n
+  }
+}
+
+// ambiguities related to ~=
+protocol _Error: Error {}
+
+extension _Error {
+  public static func ~=(lhs: Self, rhs: Self) -> Bool {
+    false
+  }
+
+  public static func ~=(lhs: Error, rhs: Self) -> Bool {
+    false
+  }
+
+  public static func ~=(lhs: Self, rhs: Error) -> Bool {
+    false
+  }
+}
+
+enum CustomError {
+  case A
+}
+
+extension CustomError: _Error {}
+
+func f(e: CustomError) {
+  if e ~= CustomError.A {}
+}
+
+// Generic overload should be preferred over concrete one because the latter is non-default literal
+struct Pattern {}
+
+func ~= (pattern: Pattern, value: String) -> Bool {
+  return false
+}
+
+extension Pattern: ExpressibleByStringLiteral {
+  init(stringLiteral value: String) {}
+}
+
+func test_default_tilda(v: String) {
+  _ = "hi" ~= v // Ok
+}
+
+struct UUID {}
+
+struct LogKey {
+  init(base: some CustomStringConvertible, foo: Int = 0) {
+  }
+
+  init(base: UUID, foo: Int = 0) {
+  }
+}
+
+@available(swift 99)
+extension LogKey {
+  init(base: String?) {
+  }
+
+  init(base: UUID?) {
+  }
+}
+
+func test_that_unavailable_init_is_not_used(x: String?) {
+  _ = LogKey(base: x ?? "??")
+}
+
+// error: value of optional type 'UID?' must be unwrapped to a value of type 'UID'
+struct S: Comparable {
+  static func <(lhs: Self, rhs: Self) -> Bool {
+    false
+  }
+}
+
+func max(_ a: S?, _ b: S?) -> S? {
+  nil
+}
+
+func test_stdlib_max_selection(s: S) -> S {
+  let new = max(s, s)
+  return new // Ok
+}
+
+// error: initializer for conditional binding must have Optional type, not 'UnsafeMutablePointer<Double>'
+do {
+  struct TestPointerConversions {
+    var p: UnsafeMutableRawPointer { get { fatalError() } }
+
+    func f(_ p: UnsafeMutableRawPointer) {
+      // The old hack (which is now removed) couldn't handle member references, only direct declaration references.
+      guard let x = UnsafeMutablePointer<Double>(OpaquePointer(self.p)) else {
+        return
+      }
+      _ = x
+
+      guard let x = UnsafeMutablePointer<Double>(OpaquePointer(p)) else {
+        // expected-error@-1 {{initializer for conditional binding must have Optional type, not 'UnsafeMutablePointer<Double>'}}
+        return
+      }
+      _ = x
+    }
+  }
+}
+
+// error: initializer 'init(_:)' requires that 'T' conform to 'BinaryInteger'
+do {
+  struct Config {
+    subscript<T>(_ key: String) -> T? { nil }
+    subscript(_ key: String) -> Any? { nil }
+  }
+
+  struct S {
+	  init(maxQueueDepth: UInt) {}
+  }
+
+  func f(config: Config) {
+    let maxQueueDepth = config["hi"] ?? 256
+    _ = S(maxQueueDepth: UInt(maxQueueDepth))
+  }
+}
+
+// `tryOptimizeGenericDisjunction` is too aggressive sometimes, make sure that `<T: FloatingPoint>`
+// overload is _not_ selected in this case.
+do {
+  func test<T: FloatingPoint>(_ expression1: @autoclosure () throws -> T, accuracy: T) -> T {}
+  func test<T: Numeric>(_ expression1: @autoclosure () throws -> T, accuracy: T) -> T {}
+
+  let result = test(10, accuracy: 1)
+  let _: Int = result
+}
+
+// swift-distributed-tracing snippet that relies on old hack behavior.
+protocol TracerInstant {
+}
+
+extension Int: TracerInstant {}
+
+do {
+  enum SpanKind {
+    case `internal`
+  }
+
+  func withSpan<Instant: TracerInstant>(
+    _ operationName: String,
+    at instant: @autoclosure () -> Instant,
+    context: @autoclosure () -> Int = 0,
+    ofKind kind: SpanKind = .internal
+  ) {}
+
+  func withSpan(
+     _ operationName: String,
+     context: @autoclosure () -> Int = 0,
+     ofKind kind: SpanKind = .internal,
+     at instant: @autoclosure () -> some TracerInstant = 42
+  ) {}
+
+  withSpan("", at: 0) // Ok
+}
+
+protocol ForAssert {
+  var isEmpty: Bool { get }
+}
+
+extension ForAssert {
+  var isEmpty: Bool { false }
+}
+
+do {
+  func assert(_ condition: @autoclosure () -> Bool, _ message: @autoclosure () -> String = String(), file: StaticString = #file, line: UInt = #line) {}
+  func assert(_ condition: Bool, _ message: @autoclosure () -> String, file: StaticString = #file, line: UInt = #line) {}
+  func assert(_ condition: Bool, file: StaticString = #fileID, line: UInt = #line) {}
+
+  struct S : ForAssert {
+    var isEmpty: Bool { false }
+  }
+
+  func test(s: S) {
+    assert(s.isEmpty, "") // Ok
+  }
+}
+
+extension Double {
+    public static func * (left: Float, right: Double) -> Double { 0 }
+}
+
+func test_non_default_literal_use(arg: Float) {
+    let v = arg * 2.0 // shouldn't use `(Float, Double) -> Double` overload
+    let _: Float = v // Ok
+}
+
+// This should be ambiguous without contextual type but was accepted before during to
+// unlabeled unary argument favoring.
+func test_variadic_static_member_is_preferred_over_partially_applied_instance_overload() {
+  struct Test {
+    func fn() {}
+    static func fn(_: Test...) {}
+  }
+
+  let t: Test
+  Test.fn(t) // Ok
+}
+
+// Unary unlabeled argument favoring hacks never applied to subscripts
+
+protocol Subscriptable {
+}
+
+extension Subscriptable {
+  subscript(key: String) -> Any? { nil }
+}
+
+struct MyValue {}
+
+extension Dictionary<String, MyValue> : Subscriptable {}
+
+func test_that_unary_argument_hacks_do_not_apply_to_subscripts(dict: [String: MyValue]) {
+  let value = dict["hello"]
+  let _: MyValue? = value // Ok
+}
+
+// Unlabeled unary argument hack was disabled if there were any protocol requirements
+// or variadic generic overloads present in the result set (regadless of their viability).
+//
+// Remove the requirement and variadic overloads and this code would start failing even
+// though it shouldn't!
+
+struct Future<T> {
+}
+
+protocol DB {
+  func get(_: Int, _: Int) -> Future<Int?>
+}
+
+extension DB {
+  func get(_: Int, _: Int = 42) async throws -> Int? { nil }
+  func get(_: Int) -> Future<Int?> { .init() }
+
+  func fetch(_: Int, _: Int = 42) async throws -> Int? { nil }
+  func fetch(_: Int) -> Future<Int?> { .init() }
+  func fetch<each T>(values: repeat each T) -> Int { 42 }
+}
+
+struct TestUnary {
+  var db: any DB
+
+  func get(v: Int) async throws {
+    guard let _ = try await self.db.get(v) else { // Ok
+      return
+    }
+
+    guard let _ = try await self.db.fetch(v) else { // Ok
+      return
+    }
+  }
+}
+
+// Prevent non-optional overload of `??` to be favored when all initializers are failable.
+
+class A {}
+class B {}
+
+protocol P {
+  init()
+}
+
+extension P {
+  init?(v: A) { self.init() }
+}
+
+struct V : P {
+  init() {}
+
+  @_disfavoredOverload
+  init?(v: B?) {}
+
+  // Important to keep this to make sure that disabled constraints
+  // are handled properly.
+  init<T: Collection>(other: T) where T.Element == Character {}
+}
+
+class TestFailableOnly {
+  var v: V?
+
+  func test(defaultB: B) {
+    guard let _ = self.v ?? V(v: defaultB) else { // OK (no warnings)
+      return
+    }
+  }
+}
+
+do {
+  @_disfavoredOverload
+  func test(over: Int, that: String = "", block: @escaping (Int) throws -> Void) async throws {}
+  func test(over: Int, that: String = "", block: @escaping (Int) throws -> Void) throws {} // expected-note {{found this candidate}}
+  func test(over: Int, other: String = "", block: @escaping (Int) throws -> Void) throws {} // expected-note {{found this candidate}}
+
+  func performLocal(v: Int, block: @escaping (Int) throws -> Void) async throws {
+    try await test(over: v, block: block) // expected-error {{ambiguous use of 'test'}}
+  }
+
+  // The hack applied only to `OverloadedDeclRefExpr`s.
+  struct MemberTest {
+    @_disfavoredOverload
+    func test(over: Int, that: String = "", block: @escaping (Int) throws -> Void) async throws {}
+    func test(over: Int, that: String = "", block: @escaping (Int) throws -> Void) throws {}
+    func test(over: Int, other: String = "", block: @escaping (Int) throws -> Void) throws {}
+
+    func performMember(v: Int, block: @escaping (Int) throws -> Void) async throws {
+      try await test(over: v, block: block) // Ok
+    }
+  }
+}
diff --git a/test/Constraints/opened_existentials.swift b/test/Constraints/opened_existentials.swift
index a8519e23d4df8..ae28b515b6218 100644
--- a/test/Constraints/opened_existentials.swift
+++ b/test/Constraints/opened_existentials.swift
@@ -565,3 +565,44 @@ do {
     types.assertTypesAreEqual()
   }
 }
+
+struct G<A>: PP3 {}
+
+protocol PP1 {
+    associatedtype A
+}
+
+extension PP1 {
+    func f(p: any PP2<G<Self.A>>) {
+        p.g(t: self)
+    }
+}
+
+protocol PP2<B> {
+    associatedtype A
+    associatedtype B: PP3 where Self.B.A == Self.A
+}
+
+extension PP2 {
+    func g<T: PP1>(t: T) where Self.B == G<T.A> {}
+}
+
+protocol PP3 {
+    associatedtype A
+}
+
+protocol PP4 {
+}
+
+do {
+  func test<T>(env: T) where T: PP4 {}
+
+  func test(env: PP4? = nil) {
+    guard let env else {
+      return
+    }
+
+    // CHECK: open_existential_expr {{.*}} location={{.*}}:[[@LINE+1]]:{{[0-9]+}} range=
+    test(env: env)
+  }
+}
diff --git a/test/Constraints/opened_existentials_overload.swift b/test/Constraints/opened_existentials_overload.swift
new file mode 100644
index 0000000000000..28eb4c1243a6a
--- /dev/null
+++ b/test/Constraints/opened_existentials_overload.swift
@@ -0,0 +1,30 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol P {}
+
+func g(_: some P) {}
+// expected-note@-1 {{required by global function 'g' where 'some P' = 'any P'}}
+
+// rdar://problem/160389221
+func good(_ x: Array<any P>) {
+  Array(x).forEach { y in g(y) }
+}
+
+extension Array {
+  var ffirst: Element? { fatalError() }
+  func ffirst(wwhere: (Element) -> Bool) -> Element { fatalError() }
+}
+
+func bad(_ x: Array<any P>) {
+  let y = x.ffirst!
+  g(y) // ok
+
+  let yy = x.ffirst
+  g(yy!) // ok
+
+  // FIXME: This is broken
+
+  g(x.ffirst!)
+  // expected-error@-1 {{type 'any P' cannot conform to 'P'}}
+  // expected-note@-2 {{only concrete types such as structs, enums and classes can conform to protocols}}
+}
diff --git a/test/Constraints/operator.swift b/test/Constraints/operator.swift
index 8e1360dcc448a..5756db1978ee1 100644
--- a/test/Constraints/operator.swift
+++ b/test/Constraints/operator.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // https://github.com/apple/swift/issues/43735
 // Test constraint simplification of chains of binary operators.
@@ -278,13 +278,14 @@ func rdar60727310() {
   func myAssertion<T>(_ a: T, _ op: ((T,T)->Bool), _ b: T) {}
   var e: Error? = nil
   myAssertion(e, ==, nil) // expected-error {{cannot convert value of type '(any Error)?' to expected argument type '(any (~Copyable & ~Escapable).Type)?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('any Error' and 'any (~Copyable & ~Escapable).Type') are expected to be equal}}
 }
 
 // https://github.com/apple/swift/issues/54877
 // FIXME: Bad diagnostic.
 func f_54877(_ e: Error) {
   func foo<T>(_ a: T, _ op: ((T, T) -> Bool)) {}
-  foo(e, ==) // expected-error {{type of expression is ambiguous without a type annotation}}
+  foo(e, ==) // expected-error {{failed to produce diagnostic for expression}}
 }
 
 // rdar://problem/62054241 - Swift compiler crashes when passing < as the sort function in sorted(by:) and the type of the array is not comparable
@@ -329,3 +330,66 @@ enum I60954 {
   }
   init?<S>(_ string: S) where S: StringProtocol {} // expected-note{{where 'S' = 'I60954'}}
 }
+
+infix operator <<<>>> : DefaultPrecedence
+
+protocol P5 {
+}
+
+struct Expr : P6 {}
+
+protocol P6: P5 {
+}
+
+extension P6 {
+  public static func <<<>>> (lhs: Self, rhs: (any P5)?) -> Expr { Expr() }
+  public static func <<<>>> (lhs: (any P5)?, rhs: Self) -> Expr { Expr() }
+  public static func <<<>>> (lhs: Self, rhs: some P6) -> Expr { Expr() }
+
+  public static prefix func ! (value: Self) -> Expr {
+    Expr()
+  }
+}
+
+extension P6 {
+  public static func != (lhs: Self, rhs: some P6) -> Expr {
+    !(lhs <<<>>> rhs) // Ok
+  }
+}
+
+do {
+  struct Value : P6 {
+  }
+
+  struct Column: P6 {
+  }
+
+  func test(col: Column, val: Value) -> Expr {
+    col <<<>>> val // Ok
+  }
+
+  func test(col: Column, val: some P6) -> Expr {
+    col <<<>>> val // Ok
+  }
+
+  func test(col: some P6, val: Value) -> Expr {
+    col <<<>>> val // Ok
+  }
+}
+
+// Make sure that ?? selects an overload that doesn't produce an optional.
+do {
+  class Obj {
+    var x: String!
+  }
+
+  class Child : Obj {
+    func x() -> String? { nil }
+    static func x(_: Int) -> String { "" }
+  }
+
+  func test(arr: [Child], v: String, defaultV: Child) -> Child {
+    let result = arr.first { $0.x == v } ?? defaultV
+    return result // Ok
+  }
+}
diff --git a/test/Constraints/optional.swift b/test/Constraints/optional.swift
index b080fd665370d..c454b26f6b5f6 100644
--- a/test/Constraints/optional.swift
+++ b/test/Constraints/optional.swift
@@ -435,7 +435,7 @@ func test_force_unwrap_not_being_too_eager() {
 // rdar://problem/57097401
 func invalidOptionalChaining(a: Any) {
   a == "="? // expected-error {{cannot use optional chaining on non-optional value of type 'String'}}
-  // expected-error@-1 {{binary operator '==' cannot be applied to operands of type 'Any' and 'String?'}}
+  // expected-error@-1 {{cannot convert value of type 'Any' to expected argument type 'String'}}
 }
 
 /// https://github.com/apple/swift/issues/54739
@@ -595,3 +595,60 @@ do {
   test(x!) // expected-error {{no exact matches in call to local function 'test'}}
   // expected-error@-1 {{cannot force unwrap value of non-optional type 'Double'}}
 }
+
+func testExtraQuestionMark(action: () -> Void, v: Int) {
+  struct Test {
+    init(action: () -> Void) {}
+  }
+
+  Test(action: action?)
+  // expected-error@-1 {{cannot use optional chaining on non-optional value of type '() -> Void'}}
+  Test(action: v?)
+  // expected-error@-1 {{cannot convert value of type 'Int' to expected argument type '() -> Void'}}
+  // expected-error@-2 {{cannot use optional chaining on non-optional value of type 'Int'}}
+}
+
+func testPassingOptionalChainAsWrongArgument() {
+  class Test {
+    func fn(_ asdType: String?) {
+    }
+  }
+
+  func test(test: Test, arr: [Int]?) {
+    test.fn(arr?.first) // expected-error {{cannot convert value of type 'Int?' to expected argument type 'String?'}}
+  }
+}
+
+// Make sure that optimizer doesn't select ??(T?, T) -> T
+protocol Syntax {
+  init?(_: some Syntax)
+}
+
+protocol SubSyntax: Syntax {}
+
+extension SubSyntax {
+  init(_: String) throws { fatalError() }
+}
+
+extension Optional : Syntax where Wrapped == Int {
+  init?(_: some Syntax) { self = .some(42) }
+}
+
+do {
+  struct TestSyntax : SubSyntax {
+    init?(_: some Syntax) {
+    }
+  }
+
+  struct S {
+    var value: Int
+  }
+
+
+  func context(from: TestSyntax?, root: some Syntax) {
+  }
+
+  func test(v: some Syntax, other: [S]) {
+    context(from: TestSyntax(v) ?? TestSyntax(other.first?.value), root: v) // Ok (no warnings)
+  }
+}
diff --git a/test/Constraints/overload.swift b/test/Constraints/overload.swift
index 59f918dddc257..699c1c06d97cc 100644
--- a/test/Constraints/overload.swift
+++ b/test/Constraints/overload.swift
@@ -349,3 +349,53 @@ do {
     }
   }
 }
+
+// Make sure that the solver properly handles mix of non-default integer and floating-point literals
+do {
+  func test(
+    withInitialValue initialValue: Float,
+    increment: Float,
+    count: Int) -> [Float] {}
+
+  func test(
+    withInitialValue initialValue: Double,
+    increment: Double,
+    count: Int) -> [Double] {}
+
+
+  func testDoubleVsFloat(count: Int) {
+    let returnedResult = test(withInitialValue: 0,
+                              increment: 0.1,
+                              count: count)
+
+    let _: [Double] = returnedResult // Ok
+  }
+}
+
+do {
+  struct S {
+    let x: Int
+    var y: Int
+  }
+
+  func overloaded(_: String) {}
+  // expected-note@-1 3 {{candidate expects value of type 'String' for parameter #1 (got 'Int')}}
+  func overloaded(_: inout Int) {}
+  // expected-note@-1 3 {{candidate expects in-out value for parameter #1 but argument is immutable}}
+
+  func testImmutable(s: S) {
+    overloaded(s.x) // expected-error {{no exact matches in call to local function 'overloaded'}}
+  }
+  
+  func testMutable(s: inout S) {
+    overloaded(s.x) // expected-error {{no exact matches in call to local function 'overloaded'}}
+  }
+
+  func testImmutableBase(s: S) {
+    overloaded(s.y) // expected-error {{no exact matches in call to local function 'overloaded'}}
+  }
+
+  func testMissingAddressOf(s: inout S) {
+    overloaded(s.y) // expected-error {{passing value of type 'Int' to an inout parameter requires explicit '&'}}
+  }
+}
diff --git a/test/Constraints/pack-expansion-expressions.swift b/test/Constraints/pack-expansion-expressions.swift
index f05040f17219d..aac7b76880256 100644
--- a/test/Constraints/pack-expansion-expressions.swift
+++ b/test/Constraints/pack-expansion-expressions.swift
@@ -327,28 +327,28 @@ func test_pack_expansions_with_closures() {
 func test_pack_expansion_specialization(tuple: (Int, String, Float)) {
   struct Data<each T> {
     init(_: repeat each T) {} // expected-note 4 {{'init(_:)' declared here}}
-    init(vals: repeat each T) {}
-    init<each U>(x: Int, _: repeat each T, y: repeat each U) {}
+    init(vals: repeat each T) {} // expected-note {{'init(vals:)' declared here}}
+    init<each U>(x: Int, _: repeat each T, y: repeat each U) {} // expected-note 3 {{'init(x:_:y:)' declared here}}
   }
 
   _ = Data<Int>() // expected-error {{missing argument for parameter #1 in call}}
   _ = Data<Int>(0) // Ok
   _ = Data<Int, String>(42, "") // Ok
-  _ = Data<Int>(42, "") // expected-error {{pack expansion requires that 'Int' and 'Int, String' have the same shape}}
+  _ = Data<Int>(42, "") // expected-error {{extra argument in call}}
   _ = Data<Int, String>((42, ""))
   // expected-error@-1 {{initializer expects 2 separate arguments; remove extra parentheses to change tuple into separate arguments}} {{25-26=}} {{32-33=}}
   _ = Data<Int, String, Float>(vals: (42, "", 0))
-  // expected-error@-1 {{pack expansion requires that 'Int, String, Float' and '(Int, String, Int)' have the same shape}}
+  // expected-error@-1 {{initializer expects 3 separate arguments; remove extra parentheses to change tuple into separate arguments}}
   _ = Data<Int, String, Float>((vals: 42, "", 0))
   // expected-error@-1 {{initializer expects 3 separate arguments; remove extra parentheses to change tuple into separate arguments}} {{32-33=}} {{48-49=}}
   _ = Data<Int, String, Float>(tuple)
   // expected-error@-1 {{initializer expects 3 separate arguments}}
   _ = Data<Int, String, Float>(x: 42, tuple)
-  // expected-error@-1 {{pack expansion requires that 'Int, String, Float' and '(Int, String, Float)' have the same shape}}
+  // expected-error@-1 {{missing arguments for parameters #2, #2 in call}}
   _ = Data<Int, String, Float>(x: 42, tuple, y: 1, 2, 3)
-  // expected-error@-1 {{pack expansion requires that 'Int, String, Float' and '(Int, String, Float)' have the same shape}}
+  // expected-error@-1 {{missing arguments for parameters #2, #2 in call}}
   _ = Data<Int, String, Float>(x: 42, (42, "", 0), y: 1, 2, 3)
-  // expected-error@-1 {{pack expansion requires that 'Int, String, Float' and '(Int, String, Int)' have the same shape}}
+  // expected-error@-1 {{missing arguments for parameters #2, #2 in call}}
 
   struct Ambiguity<each T> {
     func test(_: repeat each T) -> Int { 42 }
@@ -360,7 +360,7 @@ func test_pack_expansion_specialization(tuple: (Int, String, Float)) {
 }
 
 // rdar://107280056 - "Ambiguous without more context" with opaque return type + variadics
-protocol Q {
+protocol Q<B> {
   associatedtype B
 }
 
@@ -798,3 +798,38 @@ do {
     }
   }
 }
+
+func testInvalidDecomposition() {
+  func id<T>(_ x: T) -> T {}
+  let (a, b) = id((repeat each undefined)) // expected-error {{cannot find 'undefined' in scope}}
+}
+
+func testPackToScalarShortFormConstructor() {
+  struct S {
+    init(_ x: Int) {}
+    init<T>(_ x: T) {}
+  }
+
+  // Make sure we diagnose.
+  func foo<each T>(_ xs: repeat each T) {
+    S(repeat each xs) // expected-error {{cannot pass value pack expansion to non-pack parameter of type 'Int'}}
+  }
+}
+
+
+func test_dependent_members() {
+  struct Variadic<each T>: Q {
+    typealias B = (repeat (each T)?)
+
+    init(_: repeat each T) {}
+    static func f(_: repeat each T) -> Self {}
+  }
+
+  func test_init<C1, C2>(_ c1: C1, _ c2: C2) -> some Q<(C1?, C2?)> {
+    return Variadic(c1, c2) // Ok
+  }
+
+  func test_static<C1, C2>(_ c1: C1, _ c2: C2) -> some Q<(C1?, C2?)> {
+    return Variadic.f(c1, c2) // Ok
+  }
+}
diff --git a/test/Constraints/pack_expansion_types.swift b/test/Constraints/pack_expansion_types.swift
index f42c80a79758d..c7868d47a26e7 100644
--- a/test/Constraints/pack_expansion_types.swift
+++ b/test/Constraints/pack_expansion_types.swift
@@ -240,10 +240,10 @@ func patternInstantiationConcreteValid() {
 
 func patternInstantiationConcreteInvalid() {
   let _: Set<Int> = patternInstantiationTupleTest1()
-  // expected-error@-1 {{cannot convert value of type '(repeat Array<_>)' to specified type 'Set<Int>'}}
+  // expected-error@-1 {{cannot convert value of type 'Array<_>' to specified type 'Set<Int>'}}
   // expected-error@-2 {{could not infer pack element #0 from context}}
 
-  let _: (Array<Int>, Set<String>) = patternInstantiationTupleTest1() // expected-error {{'(repeat Array<Int, _>)' is not convertible to '(Array<Int>, Set<String>)', tuples have a different number of elements}}
+  let _: (Array<Int>, Set<String>) = patternInstantiationTupleTest1() // expected-error {{cannot convert value of type '(Array<Int>, Array<_>)' to specified type '(Array<Int>, Set<String>)'}}
   // expected-error@-1 {{could not infer pack element #1 from context}}
 }
 
@@ -274,7 +274,7 @@ func patternInstantiationGenericInvalid<each T: Hashable>(t: repeat each T) {
   let _: (repeat Set<each T>) = patternInstantiationTupleTest1() // expected-error {{cannot convert value of type '(repeat Array<each T>)' to specified type '(repeat Set<each T>)}}
   // expected-error@-1 {{generic parameter 'each T' could not be inferred}}
 
-  let _: (repeat Array<each T>, Set<String>) = patternInstantiationTupleTest1() // expected-error {{'(repeat Array<repeat each T, _>)' is not convertible to '(repeat Array<each T>, Set<String>)', tuples have a different number of elements}}
+  let _: (repeat Array<each T>, Set<String>) = patternInstantiationTupleTest1() // expected-error {{cannot convert value of type '(repeat Array<each T>, Array<_>)' to specified type '(repeat Array<each T>, Set<String>)'}}
   // expected-error@-1 {{could not infer pack element #1 from context}}
 }
 
diff --git a/test/Constraints/parameterized_existential_composition.swift b/test/Constraints/parameterized_existential_composition.swift
new file mode 100644
index 0000000000000..b666d22cb2531
--- /dev/null
+++ b/test/Constraints/parameterized_existential_composition.swift
@@ -0,0 +1,61 @@
+// RUN: %target-typecheck-verify-swift -disable-availability-checking
+
+func f1(_ s: any Sequence<Int> & Hashable) -> any Sequence<Int> {
+  return s
+}
+
+func f2(_ s: any Sequence<Int> & Hashable) -> any Hashable {
+  return s
+}
+
+func f3(_ s: any Sequence<Int> & Hashable) -> any Sequence {
+  return s
+}
+
+func f4(_ s: any Sequence<Int> & Hashable) -> any Sequence & Hashable {
+  return s
+}
+
+func f5(_ s: any Sequence<Int> & Hashable) -> any Sequence<Int> & Equatable {
+  return s
+}
+
+func f6(_ s: any Sequence<Int> & Hashable) -> any Sequence<String> & Hashable {
+  return s // expected-error {{cannot convert return expression of type 'Int' to return type 'String'}}
+}
+
+func f7(_ s: any Sequence<Int> & Hashable) -> any Sequence<String> {
+  return s // expected-error {{cannot convert return expression of type 'Int' to return type 'String'}}
+}
+
+func f8(_ s: any Collection<Int> & Hashable) -> any Sequence<Int> & Hashable {
+  return s
+}
+
+// https://github.com/swiftlang/swift/issues/71012
+
+protocol A<T> {
+  associatedtype T
+}
+protocol B {}
+typealias C = A & B
+typealias D<T> = A<T> & B
+
+struct Foo: C {
+  typealias T = Int
+}
+
+struct Bar<Value> { // expected-note {{arguments to generic parameter 'Value' ('any C' (aka 'any A & B') and 'any A<Int> & B') are expected to be equal}}
+  let value: Value
+}
+
+struct Baz<U> {
+  let bar: Bar<any D<U>>
+}
+
+func run() {
+  let foo: any C = Foo()
+  let bar = Bar(value: foo)
+  _ = Baz<Int>(bar: bar)
+  // expected-error@-1 {{cannot convert value of type 'Bar<any C>' (aka 'Bar<any A & B>') to expected argument type 'Bar<any A<Int> & B>'}}
+}
\ No newline at end of file
diff --git a/test/Constraints/parameterized_existentials.swift b/test/Constraints/parameterized_existentials.swift
index 3151c158fc42f..ba0206e251037 100644
--- a/test/Constraints/parameterized_existentials.swift
+++ b/test/Constraints/parameterized_existentials.swift
@@ -8,7 +8,7 @@ protocol P<A> {
 
 func f1(x: any P) -> any P<Int> {
   // FIXME: Bad diagnostic
-  return x // expected-error {{type of expression is ambiguous without a type annotation}}
+  return x // expected-error {{failed to produce diagnostic for expression}}
 }
 
 func f2(x: any P<Int>) -> any P {
@@ -52,4 +52,4 @@ func h3(x: (any P<Int>)?) -> (any P<String>)? {
 
 func generic1<T>(x: any P<T>) -> T {
   return x.f()
-}
\ No newline at end of file
+}
diff --git a/test/Constraints/patterns.swift b/test/Constraints/patterns.swift
index ee7e57a240b5d..0f6ccedc781a0 100644
--- a/test/Constraints/patterns.swift
+++ b/test/Constraints/patterns.swift
@@ -592,16 +592,16 @@ func f60503() {
 }
 
 // rdar://105089074
-enum EWithIdent<Id> where Id: P { // expected-note 2 {{where 'Id' = 'Int'}}
+enum EWithIdent<Id> where Id: P {
 case test(Id)
 }
 
-extension [EWithIdent<Int>] {
+extension [EWithIdent<Int>] { // expected-error {{type 'Int' does not conform to protocol 'P'}}
   func test() {
     sorted { lhs, rhs in
       switch (rhs, rhs) {
       case let (.test(x), .test(y)): break
-        // expected-error@-1 2 {{generic enum 'EWithIdent' requires that 'Int' conform to 'P'}}
+        // expected-error@-1 2 {{type 'Element' has no member 'test'}}
       case (_, _): break
       }
     }
@@ -820,3 +820,27 @@ do {
     }
   }
 }
+
+// Make sure we diagnose 'Undefined' here.
+func testUndefinedTypeInPattern(_ x: Int) {
+  switch x {
+  case Optional<Undefined>.alsoUndefined: // expected-error {{cannot find type 'Undefined' in scope}}
+    break
+  }
+  _ = {
+    switch x {
+    case Optional<Undefined>.alsoUndefined: // expected-error {{cannot find type 'Undefined' in scope}}
+      break
+    }
+  }
+}
+
+func testUndefinedInClosureVar() {
+  // Make sure we don't produce "unable to infer closure type without a type annotation"
+  _ = {
+    var x: Undefined // expected-error {{cannot find type 'Undefined' in scope}}
+  }
+  _ = {
+    for x: Undefined in [0] {} // expected-error {{cannot find type 'Undefined' in scope}}
+  }
+}
diff --git a/test/Constraints/perf_hacks_with_block_list.swift b/test/Constraints/perf_hacks_with_block_list.swift
new file mode 100644
index 0000000000000..5a965e28c1625
--- /dev/null
+++ b/test/Constraints/perf_hacks_with_block_list.swift
@@ -0,0 +1,16 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -typecheck -module-name Test -debug-constraints -blocklist-file %t/blocklist.yaml -verify %t/main.swift 2>%t.err
+// RUN: %FileCheck %t/main.swift < %t.err
+
+//--- blocklist.yaml
+---
+ShouldUseTypeCheckerPerfHacks:
+  ModuleName:
+    - Test
+
+//--- main.swift
+_ = 1 + 2 + 3
+
+// CHECK: [favored] {{.*}} bound to decl Swift.(file).Int extension.+ : (Int.Type) -> (Int, Int) -> Int
diff --git a/test/Constraints/protocols.swift b/test/Constraints/protocols.swift
index 2e1197c5b9b9f..92d5b898aa7e5 100644
--- a/test/Constraints/protocols.swift
+++ b/test/Constraints/protocols.swift
@@ -577,3 +577,11 @@ do {
 
   isFooableError(overloaded()) // Ok
 }
+
+do {
+  func takesFooables(_: [any Fooable]) {}
+
+  func test(v: String) {
+    takesFooables([v]) // expected-error {{cannot convert value of type 'String' to expected element type 'any Fooable'}}
+  }
+}
diff --git a/test/Constraints/rdar146383201.swift b/test/Constraints/rdar146383201.swift
new file mode 100644
index 0000000000000..1e26e05741375
--- /dev/null
+++ b/test/Constraints/rdar146383201.swift
@@ -0,0 +1,18 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -typecheck -verify -primary-file %t/a.swift %t/b.swift -plugin-path %swift-plugin-dir
+
+//--- a.swift
+
+func foo() {
+  _ = {
+    let i = 0
+    $bar.withValue(i) {}
+  }
+}
+
+//--- b.swift
+
+@TaskLocal
+var bar: Int?
diff --git a/test/Constraints/rdar154553285.swift b/test/Constraints/rdar154553285.swift
new file mode 100644
index 0000000000000..880c4eb2b3942
--- /dev/null
+++ b/test/Constraints/rdar154553285.swift
@@ -0,0 +1,6 @@
+// RUN: %target-typecheck-verify-swift -disable-experimental-parser-round-trip
+
+// Make sure we don't crash
+func testInvalidInInterpolation(_ x: Int) {
+  _ = "\((x, \[]))" // expected-error {{invalid component of Swift key path}}
+}
diff --git a/test/Constraints/rdar158063151.swift b/test/Constraints/rdar158063151.swift
new file mode 100644
index 0000000000000..ece6137a738c9
--- /dev/null
+++ b/test/Constraints/rdar158063151.swift
@@ -0,0 +1,16 @@
+// RUN: %target-swift-emit-silgen %s | %FileCheck %s
+
+// Make sure that the type-checker selects an `Equatable.==` instead of one from stdlib that takes _OptionalNilComparisonType
+
+struct Value: Equatable, ExpressibleByNilLiteral {
+  init(nilLiteral: ()) {
+  }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s13rdar1580631514test1vyAA5ValueV_tF : $@convention(thin) (Value) -> ()
+// function_ref static Value.__derived_struct_equals(_:_:)
+// CHECK: [[EQUALS_REF:%.*]] = function_ref @$s13rdar1580631515ValueV23__derived_struct_equalsySbAC_ACtFZ
+// CHECK-NEXT: apply [[EQUALS_REF]](%0, {{.*}})
+func test(v: Value) {
+  _ = v == nil
+}
diff --git a/test/Constraints/rdar160135085.swift b/test/Constraints/rdar160135085.swift
new file mode 100644
index 0000000000000..3ac73dcff3eb9
--- /dev/null
+++ b/test/Constraints/rdar160135085.swift
@@ -0,0 +1,24 @@
+// RUN: %empty-directory(%t/modules)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend-emit-module -emit-module-path %t/modules/A.swiftmodule -module-name A %t/a.swift
+// RUN: %target-swift-frontend-emit-module -emit-module-path %t/modules/B.swiftmodule -module-name B -I %t/modules %t/b.swift
+// RUN: %target-swift-frontend -typecheck -I %t/modules %t/c.swift
+
+//--- a.swift
+
+public struct S<T> {
+  public init(_ x: T) {}
+}
+
+//--- b.swift
+
+import A
+public typealias S = A.S
+
+//--- c.swift
+
+import A
+import B
+
+_ = S(0)
diff --git a/test/Constraints/rdar42678836.swift b/test/Constraints/rdar42678836.swift
index ff9ebe2d9b1cc..b6b92443f74fe 100644
--- a/test/Constraints/rdar42678836.swift
+++ b/test/Constraints/rdar42678836.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 func foo(chr: Character) -> String {
   return String(repeating: String(chr)) // expected-error {{missing argument for parameter 'count' in call}} {{39-39=, count: <#Int#>}}
diff --git a/test/Constraints/rdar44770297.swift b/test/Constraints/rdar44770297.swift
index 0853b150b353a..77dc228fc2551 100644
--- a/test/Constraints/rdar44770297.swift
+++ b/test/Constraints/rdar44770297.swift
@@ -10,6 +10,3 @@ func foo<T: P>(_: () throws -> T) -> T.A? { // expected-note {{where 'T' = 'Neve
 
 let _ = foo() {fatalError()} & nil
 // expected-error@-1 {{global function 'foo' requires that 'Never' conform to 'P'}}
-// expected-error@-2 {{value of optional type 'Never.A?' must be unwrapped to a value of type 'Never.A'}}
-// expected-note@-3 {{coalesce using '??' to provide a default when the optional value contains 'nil'}}
-// expected-note@-4 {{force-unwrap using '!' to abort execution if the optional value contains 'nil'}}
diff --git a/test/Constraints/rdar85263844_swift6.swift b/test/Constraints/rdar85263844_swift6.swift
index eb5e9d605443f..4b502e9a3adce 100644
--- a/test/Constraints/rdar85263844_swift6.swift
+++ b/test/Constraints/rdar85263844_swift6.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 6
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 6
 
 // rdar://85263844 - initializer 'init(_:)' requires the types be equivalent
 func rdar85263844(arr: [(q: String, a: Int)]) -> AnySequence<(question: String, answer: Int)> {
@@ -29,5 +29,5 @@ extension S4 where T == (outer: Int, y: Int) {
 
 public func rdar85263844_2(_ x: [Int]) -> S4<(outer: Int, y: Int)> {
   // FIXME: Bad error message.
-  S4(x.map { (inner: $0, y: $0) }) // expected-error {{type of expression is ambiguous without a type annotation}}
+  S4(x.map { (inner: $0, y: $0) }) // expected-error {{failed to produce diagnostic for expression}}
 }
diff --git a/test/Constraints/requirement_opening.swift b/test/Constraints/requirement_opening.swift
new file mode 100644
index 0000000000000..1fcc27e7db37a
--- /dev/null
+++ b/test/Constraints/requirement_opening.swift
@@ -0,0 +1,64 @@
+// RUN: %target-typecheck-verify-swift
+
+struct K<U> {}
+protocol Q {}
+struct ConformingType: Q {}
+
+struct S1<T: Q>: ExpressibleByArrayLiteral { // expected-note 2{{where 'T' = 'K<Int>'}}
+  init(_ x: T) {}
+  init(arrayLiteral: T...) {}
+}
+
+typealias R1<T: Q> = S1<T> // expected-note 2{{where 'T' = 'K<Int>'}}
+
+func foo(_ x: K<Int>) {
+  let _ = [x] as S1<K> // expected-error {{generic struct 'S1' requires that 'K<Int>' conform to 'Q'}}
+  let _ = [x] as R1<K> // expected-error {{generic type alias 'R1' requires that 'K<Int>' conform to 'Q'}}
+
+  let _: S1<K> = [x] // expected-error {{generic struct 'S1' requires that 'K<Int>' conform to 'Q'}}
+  let _: R1<K> = [x] // expected-error {{generic type alias 'R1' requires that 'K<Int>' conform to 'Q'}}
+}
+
+protocol P2 {
+  associatedtype A
+}
+
+struct S2<A: Q>: P2 {} // expected-note 3{{where 'A' = 'K<Int>'}}
+typealias R2<A: Q> = S2<A> // expected-note 3{{where 'A' = 'K<Int>'}}
+
+// Same as S2, but without the Q requirement.
+struct S3<A>: P2 {}
+typealias R3<A: Q> = S3<A> // expected-note 2{{where 'A' = 'K<Int>'}}
+
+func foo<T: P2>(_ y: T.A.Type) -> T {}
+let _ = foo(K<Int>.self) as S2<K> // expected-error {{generic struct 'S2' requires that 'K<Int>' conform to 'Q'}}
+let _ = foo(K<Int>.self) as R2<K> // expected-error {{generic type alias 'R2' requires that 'K<Int>' conform to 'Q'}}
+let _ = foo(K<Int>.self) as R3<K> // expected-error {{generic type alias 'R3' requires that 'K<Int>' conform to 'Q'}}
+
+let _: S2<K> = foo(K<Int>.self)   // expected-error {{generic struct 'S2' requires that 'K<Int>' conform to 'Q'}}
+let _: R2<K> = foo(K<Int>.self)   // expected-error {{generic type alias 'R2' requires that 'K<Int>' conform to 'Q'}}
+let _: R3<K> = foo(K<Int>.self)   // expected-error {{generic type alias 'R3' requires that 'K<Int>' conform to 'Q'}}
+
+func foo<T: P2>(_ x: T.Type, _ y: T.A.Type) {}
+foo(S2<_>.self, K<Int>.self) // expected-error {{generic struct 'S2' requires that 'K<Int>' conform to 'Q'}}
+foo(R2<_>.self, K<Int>.self) // expected-error {{generic type alias 'R2' requires that 'K<Int>' conform to 'Q'}}
+
+struct S4<T: Q> { // expected-note {{where 'T' = 'Int'}}
+  init(_ x: T) {}
+}
+
+_ = S4<_>(0) // expected-error {{generic struct 'S4' requires that 'Int' conform to 'Q'}}
+
+func testLocalOuterGeneric<T>(_ x: T) {
+  typealias X<U: Q> = (T, U) // expected-note {{where 'U' = 'String'}}
+  let _: X<_> = (x, "") // expected-error {{generic type alias 'X' requires that 'String' conform to 'Q'}}
+  let _: X<_> = (x, ConformingType())
+}
+
+struct TestParentGeneric<T> {
+  typealias X<U: Q> = (T, U) // expected-note {{where 'U' = 'String'}}
+  func bar(_ x: T) {
+    let _: X<_> = (x, "") // expected-error {{generic type alias 'X' requires that 'String' conform to 'Q'}}
+    let _: X<_> = (x, ConformingType())
+  }
+}
diff --git a/test/Constraints/result_builder.swift b/test/Constraints/result_builder.swift
index b7a63a80a29b5..3a7a7c2e4339f 100644
--- a/test/Constraints/result_builder.swift
+++ b/test/Constraints/result_builder.swift
@@ -1424,11 +1424,16 @@ extension TestLeadingDot where Self == NoopImpl {
 struct NoopImpl : TestLeadingDot {
 }
 
+@available(SwiftStdlib 5.1, *)
 func testLeadingDotSyntax(v: Int) {
   let x: some TestLeadingDot = .test {
     v
   }
 }
 
-testLeadingDotSyntax(v: -42)
+if #available(SwiftStdlib 5.1, *) {
+  testLeadingDotSyntax(v: -42)
+} else {
+  print("buildBlock: -42") // Fallback for the back deployment bots
+}
 // CHECK: buildBlock: -42
diff --git a/test/Constraints/result_builder_diags.swift b/test/Constraints/result_builder_diags.swift
index febaf5af4df78..709b2dc6403a9 100644
--- a/test/Constraints/result_builder_diags.swift
+++ b/test/Constraints/result_builder_diags.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -target %target-swift-5.1-abi-triple
 
 enum Either<T,U> {
   case first(T)
diff --git a/test/Constraints/same_types.swift b/test/Constraints/same_types.swift
index c97d1585660dd..c61f79c2b8dc7 100644
--- a/test/Constraints/same_types.swift
+++ b/test/Constraints/same_types.swift
@@ -282,15 +282,11 @@ protocol P2 {
 }
 
 // CHECK-LABEL: same_types.(file).structuralSameTypeRecursive1@
-// CHECK-NEXT: Generic signature: <T, U>
+// CHECK-NEXT: Generic signature: <T, U where T == <<error type>>, U == <<error type>>>
 
-// expected-error@+2 {{cannot build rewrite system for generic signature; concrete nesting limit exceeded}}
+// expected-error@+2 {{cannot build rewrite system for generic signature; concrete type nesting limit exceeded}}
 // expected-note@+1 {{τ_0_0.[P2:Assoc1].[concrete: ((((((((((((((((((((((((((((((((τ_0_0.[P2:Assoc1], τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1), τ_0_1)] => τ_0_0.[P2:Assoc1]}}
-func structuralSameTypeRecursive1<T: P2, U>(_: T, _: U)
-  where T.Assoc1 == Tuple2<T.Assoc1, U>
-  // expected-error@-1 {{'Assoc1' is not a member type of type 'T'}}
-  // expected-error@-2 {{'Assoc1' is not a member type of type 'T'}}
-{ }
+func structuralSameTypeRecursive1<T: P2, U>(_: T, _: U) where T.Assoc1 == Tuple2<T.Assoc1, U> {}
 
 protocol P3 {
 }
diff --git a/test/Constraints/subclass_shadows_operator_equals.swift b/test/Constraints/subclass_shadows_operator_equals.swift
new file mode 100644
index 0000000000000..6d94d3e45b462
--- /dev/null
+++ b/test/Constraints/subclass_shadows_operator_equals.swift
@@ -0,0 +1,74 @@
+// RUN: %target-swift-emit-silgen %s | %FileCheck %s
+
+// rdar://156454697
+
+// The appearance of DynamicSelfType as an argument type to ==
+// would lead us to choose the Base.== overload, which is less
+// "specific" than Derived.==. There was a similar bug with
+// archetypes.
+//
+// This is a SILGen test, to check the overload choice.
+
+public class Base: Equatable {
+    public static func ==(lhs: Base, rhs: Base) -> Bool {
+        return false
+    }
+}
+
+public class Derived: Base {
+    // CHECK-LABEL: sil [ossa] @$s32subclass_shadows_operator_equals7DerivedC2f1SbyF : $@convention(method) (@guaranteed Derived) -> Bool {
+    // CHECK: function_ref @$s32subclass_shadows_operator_equals7DerivedC2eeoiySbAC_ACtFZ : $@convention(method) (@guaranteed Derived, @guaranteed Derived, @thick Derived.Type) -> Bool
+    // CHECK: return
+    public func f1() -> Bool {
+        return self == self
+    }
+
+    // CHECK-LABEL: sil [ossa] @$s32subclass_shadows_operator_equals7DerivedC2f2SbyF : $@convention(method) (@guaranteed Derived) -> Bool {
+    // CHECK: function_ref @$s32subclass_shadows_operator_equals7DerivedC2eeoiySbAC_ACtFZ : $@convention(method) (@guaranteed Derived, @guaranteed Derived, @thick Derived.Type) -> Bool
+    // CHECK: return
+    public func f2() -> Bool {
+        let c = self as! Self
+        return self == c
+    }
+
+    // CHECK-LABEL: sil [ossa] @$s32subclass_shadows_operator_equals7DerivedC2f3SbyF : $@convention(method) (@guaranteed Derived) -> Bool {
+    // CHECK: function_ref @$s32subclass_shadows_operator_equals7DerivedC2eeoiySbAC_ACtFZ : $@convention(method) (@guaranteed Derived, @guaranteed Derived, @thick Derived.Type) -> Bool
+    // CHECK: return
+    public func f3() -> Bool {
+        let c = self as! Self
+        return c == self
+    }
+
+    // CHECK-LABEL: sil [ossa] @$s32subclass_shadows_operator_equals7DerivedC2f4SbyF : $@convention(method) (@guaranteed Derived) -> Bool {
+    // CHECK: function_ref @$s32subclass_shadows_operator_equals7DerivedC2eeoiySbAC_ACtFZ : $@convention(method) (@guaranteed Derived, @guaranteed Derived, @thick Derived.Type) -> Bool
+    // CHECK: return
+    public func f4() -> Bool {
+        let c = self as! Self
+        return c == c
+    }
+
+    // CHECK-LABEL: sil [ossa] @$s32subclass_shadows_operator_equals7DerivedC2g1ySbxACRbzlF : $@convention(method) <T where T : Derived> (@guaranteed T, @guaranteed Derived) -> Bool {
+    // CHECK: function_ref @$s32subclass_shadows_operator_equals7DerivedC2eeoiySbAC_ACtFZ : $@convention(method) (@guaranteed Derived, @guaranteed Derived, @thick Derived.Type) -> Bool
+    // CHECK: return
+    public func g1<T: Derived>(_ c: T) -> Bool {
+        return self == c
+    }
+
+    // CHECK-LABEL: sil [ossa] @$s32subclass_shadows_operator_equals7DerivedC2g2ySbxACRbzlF : $@convention(method) <T where T : Derived> (@guaranteed T, @guaranteed Derived) -> Bool {
+    // CHECK: function_ref @$s32subclass_shadows_operator_equals7DerivedC2eeoiySbAC_ACtFZ : $@convention(method) (@guaranteed Derived, @guaranteed Derived, @thick Derived.Type) -> Bool
+    // CHECK: return
+    public func g2<T: Derived>(_ c: T) -> Bool {
+        return c == self
+    }
+
+    // CHECK-LABEL: sil [ossa] @$s32subclass_shadows_operator_equals7DerivedC2g3ySbxACRbzlF : $@convention(method) <T where T : Derived> (@guaranteed T, @guaranteed Derived) -> Bool {
+    // CHECK: function_ref @$s32subclass_shadows_operator_equals7DerivedC2eeoiySbAC_ACtFZ : $@convention(method) (@guaranteed Derived, @guaranteed Derived, @thick Derived.Type) -> Bool
+    // CHECK: return
+    public func g3<T: Derived>(_ c: T) -> Bool {
+        return c == c
+    }
+
+    public static func ==(lhs: Derived, rhs: Derived) -> Bool {
+        return false
+    }
+}
diff --git a/test/Constraints/subscript.swift b/test/Constraints/subscript.swift
index 31b4cc9a4097f..4959791a0d65d 100644
--- a/test/Constraints/subscript.swift
+++ b/test/Constraints/subscript.swift
@@ -113,6 +113,7 @@ let squares = [ 1, 2, 3 ].reduce([:]) { (dict, n) in
 func r23670252(_ dictionary: [String : AnyObject], someObject: AnyObject) {
   let color : String?
   color = dictionary["color"]  // expected-error {{cannot assign value of type 'AnyObject?' to type 'String?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('AnyObject' and 'String') are expected to be equal}}
   _ = color
 }
 
diff --git a/test/Constraints/suspicious_bit_casts.swift b/test/Constraints/suspicious_bit_casts.swift
index baaf382d1230f..d0d61c65d38b0 100644
--- a/test/Constraints/suspicious_bit_casts.swift
+++ b/test/Constraints/suspicious_bit_casts.swift
@@ -6,7 +6,7 @@ func escapeByBitCast(f: () -> ()) -> () -> () {
 }
 
 func changeFnRep(f: @escaping () -> ()) -> @convention(block) () -> () {
-  // expected-warning@+1{{'unsafeBitCast' from function type '() -> ()' to '@convention(block) () -> ()' changes @convention and is undefined; use an implicit conversion to change conventions}}
+  // expected-warning@+1{{'unsafeBitCast' from function type '() -> ()' to '@convention(block) () -> ()' changes '@convention' and is undefined; use an implicit conversion to change conventions}}
   return unsafeBitCast(f, to: (@convention(block) () -> ()).self)
 }
 
diff --git a/test/Constraints/swift_to_c_pointer_conversions.swift.gyb b/test/Constraints/swift_to_c_pointer_conversions.swift.gyb
index f689bba38da8e..31fd487a46bd9 100644
--- a/test/Constraints/swift_to_c_pointer_conversions.swift.gyb
+++ b/test/Constraints/swift_to_c_pointer_conversions.swift.gyb
@@ -2,7 +2,7 @@
 
 // RUN: %gyb %s -o %t/swift_to_c_pointer_conversions.swift
 
-// RUN: %line-directive %t/swift_to_c_pointer_conversions.swift -- %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -import-objc-header %S/Inputs/c_pointer_conversions.h %t/swift_to_c_pointer_conversions.swift -typecheck -verify
+// RUN: %line-directive %t/swift_to_c_pointer_conversions.swift -- %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t) -import-objc-header %S/Inputs/c_pointer_conversions.h %t/swift_to_c_pointer_conversions.swift -typecheck -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
@@ -59,7 +59,7 @@ func test_${TestPtrSize}_bit_ptrs(sptr: UnsafePointer<Int${TestPtrSize}>,
   % end
 
   % for pointer in ['osptr', 'ouptr']:
-    opt_char_ptr_func(${pointer}) // expected-error {{}}
+    opt_char_ptr_func(${pointer}) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
     const_opt_char_ptr_func(${pointer}) // Ok
     unsigned_opt_char_ptr_func(${pointer}) // expected-error {{}}
     const_opt_unsigned_char_ptr_func(${pointer}) // Ok
@@ -96,13 +96,13 @@ func test_${TestPtrSize}_bit_ptrs(sptr: UnsafePointer<Int${TestPtrSize}>,
   % for pointer in ['osptr', 'ouptr']:
     % for Size in ['16', '32', '64']:
       % if Size == TestPtrSize:
-        opt_int_${TestPtrSize}_ptr_func(${pointer}) // expected-error {{}}
-        opt_uint_${TestPtrSize}_ptr_func(${pointer}) // expected-error {{}}
+        opt_int_${TestPtrSize}_ptr_func(${pointer}) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
+        opt_uint_${TestPtrSize}_ptr_func(${pointer}) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
         const_opt_int_${TestPtrSize}_ptr_func(${pointer}) // Ok
         const_opt_uint_${TestPtrSize}_ptr_func(${pointer}) // Ok
       % else:
-        opt_int_${Size}_ptr_func(${pointer}) // expected-error {{}}
-        opt_uint_${Size}_ptr_func(${pointer}) // expected-error {{}}
+        opt_int_${Size}_ptr_func(${pointer}) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
+        opt_uint_${Size}_ptr_func(${pointer}) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
         const_opt_int_${Size}_ptr_func(${pointer}) // expected-error {{}} expected-note {{}}
         const_opt_uint_${Size}_ptr_func(${pointer}) // expected-error {{}} expected-note {{}}
       % end
@@ -215,7 +215,7 @@ func test_raw_ptr_value_to_optional_promotion(
 func test_raw_ptr_optional_to_optional_conversion(
   riptr: UnsafeRawPointer?,
   rmptr: UnsafeMutableRawPointer?) {
-  opt_char_ptr_func(riptr) // expected-error {{}}
+  opt_char_ptr_func(riptr) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
   const_opt_char_ptr_func(riptr) // Ok
 
   opt_char_ptr_func(rmptr) // Ok
@@ -226,11 +226,11 @@ func test_raw_ptr_optional_to_optional_conversion(
 
   % for Ptr in ['riptr', 'rmptr']:
     % for Size in ['16', '32', '64']:
-      opt_int_${Size}_ptr_func(${Ptr}) // expected-error {{}}
-      opt_uint_${Size}_ptr_func(${Ptr}) // expected-error {{}}
+      opt_int_${Size}_ptr_func(${Ptr}) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
+      opt_uint_${Size}_ptr_func(${Ptr}) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
 
-      const_opt_int_${Size}_ptr_func(${Ptr}) // expected-error {{}}
-      const_opt_uint_${Size}_ptr_func(${Ptr}) // expected-error {{}}
+      const_opt_int_${Size}_ptr_func(${Ptr}) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
+      const_opt_uint_${Size}_ptr_func(${Ptr}) // expected-error {{}} expected-note {{arguments to generic parameter 'Wrapped'}}
     % end
   % end
 }
diff --git a/test/Constraints/tuple.swift b/test/Constraints/tuple.swift
index 72c353aecdc33..51187eed1be35 100644
--- a/test/Constraints/tuple.swift
+++ b/test/Constraints/tuple.swift
@@ -340,6 +340,7 @@ var optionalTuple3: (UInt64, Int)? = (bignum, 1) // expected-error {{cannot conv
 optionalTuple = (bignum, 1) // expected-error {{cannot assign value of type '(Int64, Int)' to type '(Int, Int)'}}
 // Optional to Optional
 optionalTuple = optionalTuple2 // expected-error {{cannot assign value of type '(Int64, Int)?' to type '(Int, Int)?'}}
+// expected-note@-1 {{arguments to generic parameter 'Wrapped' ('(Int64, Int)' and '(Int, Int)') are expected to be equal}}
 
 func testTupleLabelMismatchFuncConversion(fn1: @escaping ((x: Int, y: Int)) -> Void,
                                           fn2: @escaping () -> (x: Int, Int)) {
diff --git a/test/Constraints/tuple_arguments.swift b/test/Constraints/tuple_arguments.swift
index a24c78a443458..4a504c156203f 100644
--- a/test/Constraints/tuple_arguments.swift
+++ b/test/Constraints/tuple_arguments.swift
@@ -1660,6 +1660,7 @@ do {
   func foo(_: (() -> Void)?) {}
   func bar() -> ((()) -> Void)? { return nil }
   foo(bar()) // expected-error {{cannot convert value of type '((()) -> Void)?' to expected argument type '(() -> Void)?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('(()) -> Void' and '() -> Void') are expected to be equal}}
 }
 
 // https://github.com/apple/swift/issues/49059
@@ -1699,6 +1700,7 @@ do {
   func log<T>() -> ((T) -> Void)? { return nil }
 
   f(a: log() as ((()) -> Void)?) // expected-error {{cannot convert value of type '((()) -> Void)?' to expected argument type '(() -> Void)?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('(()) -> Void' and '() -> Void') are expected to be equal}}
 
   func logNoOptional<T>() -> (T) -> Void { }
   f(a: logNoOptional() as ((()) -> Void)) // expected-error {{cannot convert value of type '(()) -> Void' to expected argument type '() -> Void'}}
@@ -1726,7 +1728,7 @@ do {
 do {
   func f(_: Int...) {}
   let _ = [(1, 2, 3)].map(f) // expected-error {{no exact matches in call to instance method 'map'}}
-  // expected-note@-1 {{found candidate with type '(((Int, Int, Int)) -> _) -> Array<_>'}}
+  // expected-note@-1 {{found candidate with type '(((Int, Int, Int)) -> T) -> [T]'}}
 }
 
 // rdar://problem/48443263 - cannot convert value of type '() -> Void' to expected argument type '(_) -> Void'
diff --git a/test/Constraints/type_inference_from_default_exprs.swift b/test/Constraints/type_inference_from_default_exprs.swift
index 469a4bcdfc1c5..328b31d3a7fda 100644
--- a/test/Constraints/type_inference_from_default_exprs.swift
+++ b/test/Constraints/type_inference_from_default_exprs.swift
@@ -168,6 +168,11 @@ func main() {
   takesCircle(.init()) // Ok
   takesRectangle(.init())
   // expected-error@-1 {{cannot convert default value of type 'Rectangle' to expected argument type 'Circle' for parameter #0}}
+  
+  testS72199_2(x: 0)
+  testS72199_3(xs: 0, 0)
+  testS72199_4(x: 0)
+  testS72199_5(x: 0)
 }
 
 func test_magic_defaults() {
@@ -269,3 +274,19 @@ do {
 
 func testInferenceFromClosureVarInvalid<T>(x: T = { let x = "" as Int; return x }()) {}
 // expected-error@-1 {{cannot convert value of type 'String' to type 'Int' in coercion}}
+
+// https://github.com/swiftlang/swift/issues/72199
+enum S72199_1 {
+  func testS72199_1<T>(_: T = 42, _: [T]) {}
+  // expected-warning@-1 {{cannot use default expression for inference of 'T' because it is inferrable from parameters #0, #1; this will be an error in a future Swift language mode}}
+}
+
+func testS72199_2<T: P>(x: T.X, y: T = S()) { } // Ok
+func testS72199_3<each T: P>(xs: repeat (each T).X, ys: (repeat each T) = (S(), S())) {} // Ok
+
+typealias S72199_4<T> = Int
+func testS72199_4<T>(x: S72199_4<T>, y: T = "") {} // Ok
+
+func testS72199_5<T: P>(x: T.X, y: (T, T.X) = (S(), 0)) {} // Ok
+func testS72199_6<T: P>(x: T, y: (T, T.X) = (S(), 0)) {}
+// expected-error@-1 {{cannot use default expression for inference of '(T, T.X)' because it is inferrable from parameters #0, #1}}
diff --git a/test/Constraints/type_inference_from_default_exprs_swift7.swift b/test/Constraints/type_inference_from_default_exprs_swift7.swift
new file mode 100644
index 0000000000000..3c84135b6126b
--- /dev/null
+++ b/test/Constraints/type_inference_from_default_exprs_swift7.swift
@@ -0,0 +1,11 @@
+// RUN: %target-typecheck-verify-swift -swift-version 7
+// REQUIRES: swift7
+
+// https://github.com/swiftlang/swift/issues/72199
+enum S72199_1 {
+  func testS72199_1<T>(_: T = 42, _: [T]) {}
+  // expected-error@-1 {{cannot use default expression for inference of 'T' because it is inferrable from parameters #0, #1}}
+}
+
+func testS72199<T>(_: T = 42, _: [T]) {}
+// expected-error@-1 {{cannot use default expression for inference of 'T' because it is inferrable from parameters #0, #1}}
diff --git a/test/Constraints/type_of.swift b/test/Constraints/type_of.swift
index 57ea89c951ec7..226d415e0474b 100644
--- a/test/Constraints/type_of.swift
+++ b/test/Constraints/type_of.swift
@@ -87,3 +87,30 @@ do {
     }
   }
 }
+
+_ = { x in // expected-error {{cannot infer type of closure parameter 'x' without a type annotation}}
+  let _: Undefined = Swift.type(of: x)
+  // expected-error@-1 {{cannot find type 'Undefined' in scope}}
+}
+_ = {
+  func foo<T>() -> T {}
+  let _: Undefined = Swift.type(of: foo())
+  // expected-error@-1 {{cannot find type 'Undefined' in scope}}
+}
+_ = {
+  let _: Undefined = Swift.type(of: .foo)
+  // expected-error@-1 {{cannot find type 'Undefined' in scope}}
+}
+let _: Int = Swift.type(of: .foo)
+// expected-error@-1 {{cannot convert 'type(of:)' metatype to non-metatype 'Int'}}
+
+let _ = Swift.type(of: .foo)
+// expected-error@-1 {{cannot infer contextual base in reference to member 'foo'}}
+
+// FIXME: Ideally we'd include the type of the argument in the diagnostic, currently
+// we bind it to a hole before we open the closure.
+let _: Int = Swift.type(of: { (); return 0 }())
+// expected-error@-1 {{cannot convert 'type(of:)' metatype to non-metatype 'Int'}}
+
+let _: Undefined = Swift.type(of: { (); return 0 }())
+// expected-error@-1 {{cannot find type 'Undefined' in scope}}
diff --git a/test/Constraints/valid_pointer_conversions.swift b/test/Constraints/valid_pointer_conversions.swift
index 1254f38b7a297..f759c41f326e0 100644
--- a/test/Constraints/valid_pointer_conversions.swift
+++ b/test/Constraints/valid_pointer_conversions.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 func foo(_ a: [[UInt8]], _ p: [UnsafeRawPointer]) {
   foo(a, a) // expect-warning {{all paths through this function will call itself}}
diff --git a/test/Constraints/variadic_generic_constraints.swift b/test/Constraints/variadic_generic_constraints.swift
index ffb8e81dd48d7..aad4675bca27c 100644
--- a/test/Constraints/variadic_generic_constraints.swift
+++ b/test/Constraints/variadic_generic_constraints.swift
@@ -41,7 +41,7 @@ takesAnyObject()
 takesAnyObject(C(), C(), C())
 
 // FIXME: Bad diagnostic
-takesAnyObject(C(), S(), C())  // expected-error {{type of expression is ambiguous without a type annotation}}
+takesAnyObject(C(), S(), C())  // expected-error {{failed to produce diagnostic for expression}}
 
 // Same-type requirements
 
@@ -76,3 +76,29 @@ func badCallToZip<each T, each U>(t: repeat each T, u: repeat each U) {
   // expected-error@-1 {{global function 'zip(t:u:)' requires the type packs 'each T' and 'each U' have the same shape}}
   // expected-error@-2 {{pack expansion requires that 'each U' and 'each T' have the same shape}}
 }
+
+func variadicGenericsInOptionalContext(v: Int?) {
+  func test1<A, B, each C>(
+    _: A,
+    _: B,
+    _: repeat each C
+  ) throws -> (A, B, repeat each C) {
+    fatalError()
+  }
+
+  func test2<A, B, each C>(
+    _: A,
+    _: B,
+    _: (repeat each C)
+  ) throws -> (A, B, repeat each C) {
+    fatalError()
+  }
+
+  func test() {
+    guard let _ = try? test1(1, 2, 3) else { return } // Ok
+    guard let _ = try? test1(1, 2, v) else { return } // Ok
+
+    guard let _ = try? test2(1, 2, 3) else { return } // Ok
+    guard let _ = try? test2(1, 2, v) else { return } // Ok
+  }
+}
diff --git a/test/Constraints/warn_long_compile.swift b/test/Constraints/warn_long_compile.swift
index 3ae762edc85a0..cc28934a0e155 100644
--- a/test/Constraints/warn_long_compile.swift
+++ b/test/Constraints/warn_long_compile.swift
@@ -1,5 +1,4 @@
 // RUN: %target-typecheck-verify-swift -warn-long-expression-type-checking=1 -warn-long-function-bodies=1
-// REQUIRES: rdar44305428
 @_silgen_name("generic_foo")
 func foo<T>(_ x: T) -> T
 
@@ -8,6 +7,6 @@ func foo(_ x: Int) -> Int
 
 func test(m: Double) -> Int {
   // expected-warning@-1 {{global function 'test(m:)' took}}
-  return Int(foo(Float(m) / 20) * 20 - 2) + 10
+  return ~(~(~(~(~(~(~(~(~(~(~(~(0))))))))))))
   // expected-warning@-1 {{expression took}}
 }
diff --git a/test/CrossImport/Inputs/lib-templates/lib/swift/BystandingLibrary.swiftinterface b/test/CrossImport/Inputs/lib-templates/lib/swift/BystandingLibrary.swiftinterface
index ffc62c61f0696..0fdb7c0793428 100644
--- a/test/CrossImport/Inputs/lib-templates/lib/swift/BystandingLibrary.swiftinterface
+++ b/test/CrossImport/Inputs/lib-templates/lib/swift/BystandingLibrary.swiftinterface
@@ -3,5 +3,7 @@
 
 import Swift
 
-public struct BystandingLibraryTy {}
+public struct BystandingLibraryTy {
+  public init()
+}
 
diff --git a/test/CrossImport/Inputs/lib-templates/lib/swift/DeclaringLibrary.swiftinterface b/test/CrossImport/Inputs/lib-templates/lib/swift/DeclaringLibrary.swiftinterface
index 65de2e1dd0590..fec3442e371ce 100644
--- a/test/CrossImport/Inputs/lib-templates/lib/swift/DeclaringLibrary.swiftinterface
+++ b/test/CrossImport/Inputs/lib-templates/lib/swift/DeclaringLibrary.swiftinterface
@@ -3,5 +3,7 @@
 
 import Swift
 
-public struct DeclaringLibraryTy {}
+public struct DeclaringLibraryTy {
+  public init()
+}
 public struct ShadowTy {}
diff --git a/test/CrossImport/Inputs/lib-templates/lib/swift/_OverlayLibrary.swiftinterface b/test/CrossImport/Inputs/lib-templates/lib/swift/_OverlayLibrary.swiftinterface
index cb588dd49b875..8c1475e0aa57c 100644
--- a/test/CrossImport/Inputs/lib-templates/lib/swift/_OverlayLibrary.swiftinterface
+++ b/test/CrossImport/Inputs/lib-templates/lib/swift/_OverlayLibrary.swiftinterface
@@ -11,3 +11,11 @@ public struct OverlayLibraryTy {
 }
 
 public struct ShadowTy {}
+
+extension DeclaringLibrary.DeclaringLibraryTy {
+  public func overlayMember()
+}
+
+extension BystandingLibrary.BystandingLibraryTy {
+  public func overlayMember()
+}
diff --git a/test/CrossImport/access-level-imports-errors.swift b/test/CrossImport/access-level-imports-errors.swift
index 93363fd88696e..5a3f4acb7695c 100644
--- a/test/CrossImport/access-level-imports-errors.swift
+++ b/test/CrossImport/access-level-imports-errors.swift
@@ -8,7 +8,7 @@
 // RUN: %target-swift-emit-module-interface(%t/lib/swift/SomeUnrelatedModule.swiftinterface) %t/SomeUnrelatedModule.swift -module-name SomeUnrelatedModule
 
 //--- BothPublic.swift
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/BothPublic.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/BothPublic.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify -verify-ignore-unrelated
 
 public import DeclaringLibrary
 public import BystandingLibrary
@@ -18,7 +18,7 @@ public func fn(_: OverlayLibraryTy) {}
 
 
 //--- BothHidden.swift
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/BothHidden.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/BothHidden.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify -verify-ignore-unrelated
 
 internal import DeclaringLibrary
 internal import BystandingLibrary
@@ -29,7 +29,7 @@ public func fn(_: OverlayLibraryTy) {}
 
 
 //--- FirstHidden.swift
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/FirstHidden.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/FirstHidden.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify -verify-ignore-unrelated
 
 internal import DeclaringLibrary
 public import BystandingLibrary
@@ -40,7 +40,7 @@ public func fn(_: OverlayLibraryTy) {}
 
 
 //--- SecondHidden.swift
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/SecondHidden.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/SecondHidden.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify -verify-ignore-unrelated
 
 public import DeclaringLibrary
 internal import BystandingLibrary
@@ -51,7 +51,7 @@ public func fn(_: OverlayLibraryTy) {}
 
 
 //--- PrivateVsInternal.swift
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/PrivateVsInternal.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/PrivateVsInternal.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify -verify-ignore-unrelated
 
 private import DeclaringLibrary
 internal import BystandingLibrary
@@ -62,7 +62,7 @@ internal func fn(_: OverlayLibraryTy) {}
 
 
 //--- InternalVsPrivate.swift
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/InternalVsPrivate.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/InternalVsPrivate.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify -verify-ignore-unrelated
 
 internal import DeclaringLibrary
 private import BystandingLibrary
@@ -73,7 +73,7 @@ internal func fn(_: OverlayLibraryTy) {}
 
 
 //--- UnusedOverlay.swift
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/UnusedOverlay.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/UnusedOverlay.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify -verify-ignore-unrelated
 
 public import DeclaringLibrary // expected-warning {{public import of 'DeclaringLibrary' was not used in public declarations or inlinable code}}
 public import BystandingLibrary // expected-warning {{public import of 'BystandingLibrary' was not used in public declarations or inlinable code}}
diff --git a/test/CrossImport/loading.swift b/test/CrossImport/loading.swift
index 2cd71c8090b6c..c3aa867f47113 100644
--- a/test/CrossImport/loading.swift
+++ b/test/CrossImport/loading.swift
@@ -10,9 +10,9 @@
 // the test is incorrectly constructed.
 //
 
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDIRECTLY_IMPORT_OVERLAYS
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -DTHIN_LIBRARY 2>/dev/null
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DTHIN_LIBRARY -DNEVER_IMPORTED 2>/dev/null
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDIRECTLY_IMPORT_OVERLAYS
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -DTHIN_LIBRARY 2>/dev/null
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DTHIN_LIBRARY -DNEVER_IMPORTED 2>/dev/null
 
 //
 // Actual test cases
@@ -20,26 +20,26 @@
 
 // Check that we find the overlay in all layouts of Swift and Clang modules,
 // and that we generate correct dependencies.
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DTHIN_LIBRARY -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=ThinLibrary -DTARGET=%module-target-triple %s
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DFAT_LIBRARY -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=FatLibrary -DTARGET=%module-target-triple %s
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DCLANG_LIBRARY -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=ClangLibrary -DTARGET=%module-target-triple %s
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DCLANG_LIBRARY_SUBMODULE -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=ClangLibrary -DTARGET=%module-target-triple %s
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DSWIFT_FRAMEWORK -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=SwiftFramework -DTARGET=%module-target-triple %s
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DCLANG_FRAMEWORK -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=ClangFramework -DTARGET=%module-target-triple %s
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DOVERLAID_CLANG_FRAMEWORK -emit-dependencies-path - | %FileCheck -check-prefix=DEPS -DMODULE=OverlaidClangFramework -DTARGET=%module-target-triple %s
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DTHIN_LIBRARY -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=ThinLibrary -DTARGET=%module-target-triple %s
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DFAT_LIBRARY -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=FatLibrary -DTARGET=%module-target-triple %s
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DCLANG_LIBRARY -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=ClangLibrary -DTARGET=%module-target-triple %s
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DCLANG_LIBRARY_SUBMODULE -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=ClangLibrary -DTARGET=%module-target-triple %s
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DSWIFT_FRAMEWORK -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=SwiftFramework -DTARGET=%module-target-triple %s
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DCLANG_FRAMEWORK -emit-dependencies-path - | %FileCheck -check-prefixes=DEPS,DEPS-MOST -DMODULE=ClangFramework -DTARGET=%module-target-triple %s
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DOVERLAID_CLANG_FRAMEWORK -emit-dependencies-path - | %FileCheck -check-prefix=DEPS -DMODULE=OverlaidClangFramework -DTARGET=%module-target-triple %s
 
 // Make sure order doesn't matter.
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DALWAYS_IMPORTED_LAST -DTHIN_LIBRARY
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DALWAYS_IMPORTED_LAST -DTHIN_LIBRARY
 
 // Negative cases (one side of overlay is missing).
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks 2>/dev/null
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DTHIN_LIBRARY 2>/dev/null
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DFAT_LIBRARY 2>/dev/null
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DCLANG_LIBRARY 2>/dev/null
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DCLANG_LIBRARY_SUBMODULE 2>/dev/null
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DSWIFT_FRAMEWORK 2>/dev/null
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DCLANG_FRAMEWORK 2>/dev/null
-// RUN: not %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DOVERLAID_CLANG_FRAMEWORK 2>/dev/null
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks 2>/dev/null
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DTHIN_LIBRARY 2>/dev/null
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DFAT_LIBRARY 2>/dev/null
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DCLANG_LIBRARY 2>/dev/null
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DCLANG_LIBRARY_SUBMODULE 2>/dev/null
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DSWIFT_FRAMEWORK 2>/dev/null
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DCLANG_FRAMEWORK 2>/dev/null
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDONT_ALWAYS_IMPORT -DOVERLAID_CLANG_FRAMEWORK 2>/dev/null
 
 //
 // Actual test code:
diff --git a/test/CrossImport/member-import-visibility.swift b/test/CrossImport/member-import-visibility.swift
new file mode 100644
index 0000000000000..eb8d3833756a8
--- /dev/null
+++ b/test/CrossImport/member-import-visibility.swift
@@ -0,0 +1,57 @@
+// RUN: %empty-directory(%t)
+// RUN: cp -r %S/Inputs/lib-templates/* %t/
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -typecheck -verify -enable-cross-import-overlays \
+// RUN:   %t/OnlyDeclaring.swift \
+// RUN:   %t/OnlyBystanding.swift \
+// RUN:   %t/NeitherDeclaringNorBystanding.swift \
+// RUN:   %t/BothDeclaringAndBystanding.swift \
+// RUN:   -I %t/include -I %t/lib/swift -F %t/Frameworks \
+// RUN:   -enable-upcoming-feature MemberImportVisibility
+
+// REQUIRES: swift_feature_MemberImportVisibility
+
+//--- OnlyDeclaring.swift
+
+import DeclaringLibrary
+// expected-note 2 {{add import of module 'BystandingLibrary'}}
+
+private func test() {
+  returnsDeclaringTy().overlayMember() // expected-error {{instance method 'overlayMember()' is not available due to missing import of defining module 'BystandingLibrary'}}
+  returnsBystandingTy().overlayMember() // expected-error {{instance method 'overlayMember()' is not available due to missing import of defining module 'BystandingLibrary'}}
+}
+
+//--- OnlyBystanding.swift
+
+import BystandingLibrary
+// expected-note 2 {{add import of module 'DeclaringLibrary'}}
+
+private func test() {
+  returnsDeclaringTy().overlayMember() // expected-error {{instance method 'overlayMember()' is not available due to missing import of defining module 'DeclaringLibrary'}}
+  returnsBystandingTy().overlayMember() // expected-error {{instance method 'overlayMember()' is not available due to missing import of defining module 'DeclaringLibrary'}}
+}
+
+//--- NeitherDeclaringNorBystanding.swift
+
+import Swift
+// expected-note 2 {{add import of module 'BystandingLibrary'}}
+// expected-note@-1 2 {{add import of module 'DeclaringLibrary'}}
+
+private func test() {
+  returnsDeclaringTy().overlayMember() // expected-error {{instance method 'overlayMember()' is not available due to missing imports of defining modules 'BystandingLibrary' and 'DeclaringLibrary'}}
+  returnsBystandingTy().overlayMember() // expected-error {{instance method 'overlayMember()' is not available due to missing imports of defining modules 'BystandingLibrary' and 'DeclaringLibrary'}}
+}
+
+//--- BothDeclaringAndBystanding.swift
+
+import DeclaringLibrary
+import BystandingLibrary
+
+func returnsDeclaringTy() -> DeclaringLibraryTy {
+  return DeclaringLibraryTy()
+}
+
+func returnsBystandingTy() -> BystandingLibraryTy {
+  return BystandingLibraryTy()
+}
diff --git a/test/CrossImport/transitive.swift b/test/CrossImport/transitive.swift
index b8c17509c7675..ff5c0c3b77020 100644
--- a/test/CrossImport/transitive.swift
+++ b/test/CrossImport/transitive.swift
@@ -3,8 +3,8 @@
 // RUN: %empty-directory(%t)
 // RUN: cp -r %S/Inputs/lib-templates/* %t/
 
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDIRECT_FIRST
-// RUN: %target-typecheck-verify-swift -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDIRECT_SECOND
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDIRECT_FIRST
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-cross-import-overlays -I %t/include -I %t/lib/swift -F %t/Frameworks -DDIRECT_SECOND
 
 #if DIRECT_FIRST
 import ThinLibrary
diff --git a/test/DebugInfo/BoundGenericStruct.swift b/test/DebugInfo/BoundGenericStruct.swift
index a8aa816e80c86..f324cdc003c4f 100644
--- a/test/DebugInfo/BoundGenericStruct.swift
+++ b/test/DebugInfo/BoundGenericStruct.swift
@@ -31,12 +31,11 @@ public let inner = S2<Double>.Inner(t:4.2)
 
 // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "Inner", 
 // CHECK-SAME: size: 64, {{.*}}identifier: "$s18BoundGenericStruct2S2V5InnerVySd_GD")
-// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "$s18BoundGenericStruct2S2VyxGD", 
-// CHECK-SAME: flags: DIFlagFwdDecl, runtimeLang: DW_LANG_Swift)
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, {{.*}}flags: DIFlagFwdDecl, runtimeLang: DW_LANG_Swift, {{.*}}identifier: "$s18BoundGenericStruct2S2VyxGD"
 
 // DWARF-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "$s18BoundGenericStruct2S2V5InnerVySd_GD", scope: ![[SCOPE1:[0-9]+]], {{.*}}flags: DIFlagFwdDecl, runtimeLang: DW_LANG_Swift, templateParams: ![[PARAMS2:[0-9]+]])
 
-// DWARF-DAG: ![[SCOPE1]] = !DICompositeType(tag: DW_TAG_structure_type, name: "$s18BoundGenericStruct2S2VyxGD", 
+// DWARF-DAG: ![[SCOPE1]] = !DICompositeType(tag: DW_TAG_structure_type, {{.*}}identifier: "$s18BoundGenericStruct2S2VyxGD"
 
 // DWARF-DAG: ![[PARAMS2]] = !{![[PARAMS3:[0-9]+]]}
 // DWARF-DAG: ![[PARAMS3]] = !DITemplateTypeParameter(type: ![[PARAMS4:[0-9]+]])
diff --git a/test/DebugInfo/EagerTypeMetadata.swift b/test/DebugInfo/EagerTypeMetadata.swift
index 1f53cb5cae90e..e216d788fc7de 100644
--- a/test/DebugInfo/EagerTypeMetadata.swift
+++ b/test/DebugInfo/EagerTypeMetadata.swift
@@ -13,6 +13,6 @@ public class C<T>
 }
 // CHECK: !DIDerivedType(tag: DW_TAG_typedef, name: "T",
 // CHECK-SAME:           baseType: ![[PTRTY:[0-9]+]]
-// CHECK: ![[PTRTY]] = !DIDerivedType(tag: DW_TAG_pointer_type, name: "$sBpD", baseType: null, size: {{64|32}}, flags: DIFlagArtificial | DIFlagObjectPointer)
+// CHECK: ![[PTRTY]] = !DIDerivedType(tag: DW_TAG_pointer_type, name: "$sBpD", baseType: null, size: {{64|32}})
 // CHECK: ![[LOC]] = !DILocation(line: 0,
 
diff --git a/test/DebugInfo/ErrorVar.swift b/test/DebugInfo/ErrorVar.swift
index 75c7fccf7a13f..f59c27d4eb320 100644
--- a/test/DebugInfo/ErrorVar.swift
+++ b/test/DebugInfo/ErrorVar.swift
@@ -14,7 +14,7 @@ func simple(_ placeholder: Int64) throws -> () {
   // CHECK: define {{.*}}void @"$s8ErrorVar6simpleyys5Int64VKF"(
   // CHECK-SAME: i64
   // CHECK-SAME: %swift.refcounted* {{.*}}swiftself
-  // CHECK-SAME: %swift.error** noalias nocapture dereferenceable(4)
+  // CHECK-SAME: %swift.error** noalias {{(nocapture|captures\(none\))}} dereferenceable(4)
   // CHECK: #dbg_declare
   // CHECK: #dbg_declare({{.*}}, ![[ERROR:[0-9]+]], !DIExpression(DW_OP_deref)
   // CHECK-DAG: ![[ERRTY:.*]] = !DICompositeType({{.*}}identifier: "$ss5Error_pD"
diff --git a/test/DebugInfo/Errors.swift b/test/DebugInfo/Errors.swift
index 41f5b31e732ac..9dc1f3b715d67 100644
--- a/test/DebugInfo/Errors.swift
+++ b/test/DebugInfo/Errors.swift
@@ -3,7 +3,7 @@ public enum E : Error { case Err }
 
 // Function throws.
 public func throwError() throws { throw E.Err }
-// CHECK: !DISubprogram(name: "throwError", {{.*}}thrownTypes: ![[THROWN:.*]])
+// CHECK-DAG: !DISubprogram(name: "throwError", {{.*}}thrownTypes: ![[THROWN:.*]])
 // CHECK-DAG: ![[THROWN]] = !{![[ERROR:[0-9]+]]}
 // CHECK-DAG: ![[ERROR]] = !DICompositeType(tag: DW_TAG_structure_type, name: "Error"
 
diff --git a/test/DebugInfo/Imports.swift b/test/DebugInfo/Imports.swift
index ce98458c03040..d79a5fe62a37c 100644
--- a/test/DebugInfo/Imports.swift
+++ b/test/DebugInfo/Imports.swift
@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module-path %t/basic.swiftmodule %S/basic.swift
+// RUN: %target-swift-frontend -emit-module-path %t/advanced.swiftmodule %S/advanced.swift
 
 // RUN: %target-swift-frontend -emit-ir -module-name Foo %s -I %t -g -o - | %FileCheck %s
 // RUN: %target-swift-frontend -c -module-name Foo %s -I %t -g -o %t.o
@@ -10,13 +10,13 @@
 // CHECK-DAG: ![[THISFILE]] = !DIFile(filename: "{{.*}}test{{/|\\\\}}DebugInfo{{/|\\\\}}Imports.swift",
 // CHECK-DAG: ![[SWIFTMODULE:[0-9]+]] = !DIModule({{.*}}, name: "Swift"
 // CHECK-DAG: !DIImportedEntity(tag: DW_TAG_imported_module, scope: ![[THISFILE]], entity: ![[SWIFTMODULE]]
-// CHECK-DAG: ![[BASICMODULE:[0-9]+]] = !DIModule({{.*}}, name: "basic"
+// CHECK-DAG: ![[BASICMODULE:[0-9]+]] = !DIModule({{.*}}, name: "advanced"
 // CHECK-DAG: !DIImportedEntity(tag: DW_TAG_imported_module, scope: ![[THISFILE]], entity: ![[BASICMODULE]]
-import basic
+import advanced
 import typealias Swift.Optional
 
 func markUsed<T>(_ t: T) {}
-markUsed(basic.foo(1, 2))
+markUsed(advanced.foo(1, 2))
 
 // DWARF: .debug_info
 // DWARF: DW_TAG_module
@@ -26,7 +26,7 @@ markUsed(basic.foo(1, 2))
 // DWARF:   DW_AT_name ("Swift")
 // DWARF:   DW_AT_LLVM_include_path
 // DWARF: DW_TAG_module
-// DWARF:   DW_AT_name ("basic")
+// DWARF:   DW_AT_name ("advanced")
 
 // DWARF-NOT: "Swift.Optional"
 
diff --git a/test/DebugInfo/NestedTypes.swift b/test/DebugInfo/NestedTypes.swift
index eb4c82a85394e..b2b7857aa9169 100644
--- a/test/DebugInfo/NestedTypes.swift
+++ b/test/DebugInfo/NestedTypes.swift
@@ -16,3 +16,27 @@ public let e : Enum = .WithClass(C())
 // CHECK: !DIDerivedType(tag: DW_TAG_member, name: "WithStruct",
 // CHECK-SAME:           size: 128)
 
+public struct D<U> {
+  var v : V
+  let u: U
+}
+
+extension D {
+  struct V {
+    internal var obj: Int
+  }
+}
+
+public let d = D<Int>(v: D.V(obj: 1), u: 2)
+
+// CHECK: ![[D:.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "D"
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "V", scope: ![[D]],
+
+public struct Unused {
+  public struct W {}
+}
+
+public let w = Unused.W()
+
+// CHECK-DAG: ![[Unused:.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "Unused"
+// CHECK-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "W", scope: ![[Unused]],
diff --git a/test/DebugInfo/ParseableInterfaceImports.swift b/test/DebugInfo/ParseableInterfaceImports.swift
index e05c0533a8411..1a13c2543d56c 100644
--- a/test/DebugInfo/ParseableInterfaceImports.swift
+++ b/test/DebugInfo/ParseableInterfaceImports.swift
@@ -1,23 +1,23 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend-typecheck %S/basic.swift \
-// RUN:    -emit-module-interface-path %t/basic.swiftinterface
+// RUN: %target-swift-frontend-typecheck %S/advanced.swift \
+// RUN:    -emit-module-interface-path %t/advanced.swiftinterface
 // RUN: %target-swift-frontend -emit-ir -module-name Foo %s -I %t -g -o - \
 // RUN:    | %FileCheck %s
 // RUN: %target-swift-frontend -emit-ir -module-name Foo %s -I %t -g -o - \
 // RUN:    -sdk %t | %FileCheck %s --check-prefix=SDK
 
-import basic
+import advanced
 
-// CHECK: !DIModule(scope: null, name: "basic",
+// CHECK: !DIModule(scope: null, name: "advanced",
 // CHECK-SAME:      includePath: "
-// CHECK-SAME:      basic.swiftinterface"
+// CHECK-SAME:      advanced.swiftinterface"
 
 // Even if the module interface is in the SDK, we still return the path
 // to the swiftinterface.
-// SDK:   !DIModule(scope: null, name: "basic",
+// SDK:   !DIModule(scope: null, name: "advanced",
 // SDK-SAME:        includePath: "
-// SDK-SAME:        basic{{.*}}.swiftinterface"
+// SDK-SAME:        advanced{{.*}}.swiftinterface"
 
 func markUsed<T>(_ t: T) {}
-markUsed(basic.foo(1, 2))
+markUsed(advanced.foo(1, 2))
 
diff --git a/test/DebugInfo/WeakCapture.swift b/test/DebugInfo/WeakCapture.swift
index b3c86fdd54c42..d67839d5053b6 100644
--- a/test/DebugInfo/WeakCapture.swift
+++ b/test/DebugInfo/WeakCapture.swift
@@ -1,4 +1,8 @@
 // RUN: %target-swift-frontend %s -emit-ir -g -o - | %FileCheck %s
+// RUN: %target-swift-frontend %s -enable-upcoming-feature ImmutableWeakCaptures -emit-ir -g -o - | %FileCheck %s
+
+// REQUIRES: swift_feature_ImmutableWeakCaptures
+
 class A {
     init(handler: (() -> ())) { }
 }
diff --git a/test/DebugInfo/advanced.swift b/test/DebugInfo/advanced.swift
new file mode 100644
index 0000000000000..7fe50b54106b1
--- /dev/null
+++ b/test/DebugInfo/advanced.swift
@@ -0,0 +1,81 @@
+// A (no longer) basic test for debug info.
+// --------------------------------------------------------------------
+// Verify that we don't emit any type info with -gline-tables-only.
+// RUN: %target-swift-frontend %s -emit-ir -gline-tables-only -o - \
+// RUN:   | %FileCheck %s --check-prefix CHECK-LINETABLES
+// CHECK: !dbg
+// CHECK-LINETABLES-NOT: DI{{.*}}Variable
+// CHECK-LINETABLES-NOT: DW_TAG_structure_type
+// CHECK-LINETABLES-NOT: DIBasicType
+// --------------------------------------------------------------------
+// Now check that we do generate line+scope info with -g.
+// RUN: %target-swift-frontend %/s -emit-ir -g -o - \
+// RUN:   | %FileCheck %s --check-prefixes CHECK,DWARF-CHECK
+// --------------------------------------------------------------------
+// Currently -gdwarf-types should give the same results as -g.
+// RUN: %target-swift-frontend  %/s -emit-ir -gdwarf-types -o - \
+// RUN:   | %FileCheck %s --check-prefixes CHECK,DWARF-CHECK
+// --------------------------------------------------------------------
+// Verify that -g -debug-info-format=dwarf gives the same results as -g.
+// RUN: %target-swift-frontend %/s -emit-ir -g -debug-info-format=dwarf -o - \
+// RUN:   | %FileCheck %s --check-prefixes CHECK,DWARF-CHECK
+// --------------------------------------------------------------------
+// RUN: %target-swift-frontend %/s -emit-ir -g -debug-info-format=codeview -o - \
+// RUN:   | %FileCheck %s --check-prefixes CHECK,CV-CHECK
+// --------------------------------------------------------------------
+//
+// CHECK: foo
+// CHECK-DAG: ret{{.*}}, !dbg ![[RET:[0-9]+]]
+// CHECK-DAG: ![[FOO:[0-9]+]] = distinct !DISubprogram(name: "foo",{{.*}} line: [[@LINE+2]],{{.*}} type: ![[FOOTYPE:[0-9]+]]
+public
+func foo(_ a: Int64, _ b: Int64) -> Int64 {
+     var a = a
+     var b = b
+     // CHECK-DAG: ![[ALOC:.*]] = !DILocation(line: [[@LINE-3]],{{.*}} scope: ![[FOO]])
+     // Check that a is the first and b is the second argument.
+     // CHECK-DAG: store i64 %0, ptr [[AADDR:.*]], align
+     // CHECK-DAG: store i64 %1, ptr [[BADDR:.*]], align
+     // CHECK-DAG: [[AVAL:%.*]] = getelementptr inbounds {{.*}}, [[AMEM:.*]], i32 0, i32 0
+     // CHECK-DAG: [[BVAL:%.*]] = getelementptr inbounds {{.*}}, [[BMEM:.*]], i32 0, i32 0
+     // CHECK-DAG: #dbg_declare(ptr [[AADDR]], ![[AARG:.*]], !DIExpression(), ![[ALOC]]
+     // CHECK-DAG: #dbg_declare(ptr [[BADDR]], ![[BARG:.*]], !DIExpression()
+     // CHECK-DAG: ![[AARG]] = !DILocalVariable(name: "a", arg: 1
+     // CHECK-DAG: ![[BARG]] = !DILocalVariable(name: "b", arg: 2
+     if b != 0 {
+       // CHECK-DAG: !DILexicalBlock({{.*}} line: [[@LINE-1]]
+       // Transparent inlined multiply:
+       // CHECK-DAG: smul{{.*}}, !dbg ![[MUL:[0-9]+]]
+       // CHECK-DAG: [[MUL]] = !DILocation(line: [[@LINE+1]],
+       return a*b
+     } else {
+       // CHECK-DAG: ![[PARENT:[0-9]+]] = distinct !DILexicalBlock({{.*}} line: [[@LINE-1]]
+       // CHECK-DAG: ![[VARSCOPE:[0-9]+]] = distinct !DILexicalBlock({{.*}} line: [[@LINE+1]]
+       var c: Int64 = 42
+       // CHECK-DAG: ![[CONDITION:[0-9]+]] = distinct !DILexicalBlock(scope: ![[VARSCOPE]], {{.*}}, line: [[@LINE+1]]
+       if a == 0 {
+         // CHECK-DAG: !DILexicalBlock(scope: ![[CONDITION]], {{.*}}, line: [[@LINE-1]]
+         // What about a nested scope?
+         return 0
+       }
+       return c
+     }
+}
+
+// CHECK-DAG: ![[MAINFILE:[0-9]+]] = !DIFile(filename: "{{.*}}DebugInfo/advanced.swift", directory: "{{.*}}")
+// CHECK-DAG: !DICompileUnit(language: DW_LANG_Swift, file: ![[MAINFILE]],{{.*}} producer: "{{.*}}Swift version{{.*}},{{.*}}
+// CHECK-DAG: !DISubprogram(name: "main", {{.*}}file: ![[MAINFILE]],
+
+// Function type for foo.
+// CHECK-DAG: ![[FOOTYPE]] = !DISubroutineType(types: ![[PARAMTYPES:[0-9]+]])
+// CHECK-DAG: ![[INT64:.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "Int64", {{.*}}, identifier: "$ss5Int64VD")
+// CHECK-DAG: ![[PARAMTYPES]] = !{![[INT64]], ![[INT64]], ![[INT64]]}
+// Import of the main module with the implicit name.
+// CHECK-DAG: !DIImportedEntity(tag: DW_TAG_imported_module, scope: ![[MAINFILE]], entity: ![[MAINMODULE:[0-9]+]], file: ![[MAINFILE]])
+// CHECK-DAG: ![[MAINMODULE]] = !DIModule({{.*}}, name: "advanced"
+
+// DWARF Version
+// DWARF-CHECK-DAG:  i32 7, !"Dwarf Version", i32 4}
+// CV-CHECK-DAG: i32 2, !"CodeView", i32 1}
+
+// Debug Info Version
+// CHECK-DAG:  i32 2, !"Debug Info Version", i32
diff --git a/test/DebugInfo/basic.swift b/test/DebugInfo/basic.swift
index ca64ef87f9bf2..8f2ff92818b67 100644
--- a/test/DebugInfo/basic.swift
+++ b/test/DebugInfo/basic.swift
@@ -1,6 +1,8 @@
-// A (no longer) basic test for debug info.
+// A basic test for debug info.
+// UNSUPPORTED: OS=windows-msvc
 // --------------------------------------------------------------------
-// Verify that we don't emit any debug info by default.
+// Verify that we don't emit any debug info by default. This test has a
+// specific Windows implementation in debug_basic_windows.swift.
 // RUN: %target-swift-frontend %s -emit-ir -o - \
 // RUN:   | %FileCheck %s --check-prefix NDEBUG
 // NDEBUG: source_filename
@@ -10,83 +12,7 @@
 // Verify that we don't emit any debug info with -gnone.
 // RUN: %target-swift-frontend %s -emit-ir -gnone -o - \
 // RUN:   | %FileCheck %s --check-prefix NDEBUG
-// --------------------------------------------------------------------
-// Verify that we don't emit any type info with -gline-tables-only.
-// RUN: %target-swift-frontend %s -emit-ir -gline-tables-only -o - \
-// RUN:   | %FileCheck %s --check-prefix CHECK-LINETABLES
-// CHECK: !dbg
-// CHECK-LINETABLES-NOT: DI{{.*}}Variable
-// CHECK-LINETABLES-NOT: DW_TAG_structure_type
-// CHECK-LINETABLES-NOT: DIBasicType
-// --------------------------------------------------------------------
-// Now check that we do generate line+scope info with -g.
-// RUN: %target-swift-frontend %/s -emit-ir -g -o - \
-// RUN:   | %FileCheck %s --check-prefixes CHECK,DWARF-CHECK
-// --------------------------------------------------------------------
-// Currently -gdwarf-types should give the same results as -g.
-// RUN: %target-swift-frontend  %/s -emit-ir -gdwarf-types -o - \
-// RUN:   | %FileCheck %s --check-prefixes CHECK,DWARF-CHECK
-// --------------------------------------------------------------------
-// Verify that -g -debug-info-format=dwarf gives the same results as -g.
-// RUN: %target-swift-frontend %/s -emit-ir -g -debug-info-format=dwarf -o - \
-// RUN:   | %FileCheck %s --check-prefixes CHECK,DWARF-CHECK
-// --------------------------------------------------------------------
-// RUN: %target-swift-frontend %/s -emit-ir -g -debug-info-format=codeview -o - \
-// RUN:   | %FileCheck %s --check-prefixes CHECK,CV-CHECK
-// --------------------------------------------------------------------
-//
-// CHECK: foo
-// CHECK-DAG: ret{{.*}}, !dbg ![[RET:[0-9]+]]
-// CHECK-DAG: ![[FOO:[0-9]+]] = distinct !DISubprogram(name: "foo",{{.*}} line: [[@LINE+2]],{{.*}} type: ![[FOOTYPE:[0-9]+]]
-public
-func foo(_ a: Int64, _ b: Int64) -> Int64 {
-     var a = a
-     var b = b
-     // CHECK-DAG: ![[ALOC:.*]] = !DILocation(line: [[@LINE-3]],{{.*}} scope: ![[FOO]])
-     // Check that a is the first and b is the second argument.
-     // CHECK-DAG: store i64 %0, ptr [[AADDR:.*]], align
-     // CHECK-DAG: store i64 %1, ptr [[BADDR:.*]], align
-     // CHECK-DAG: [[AVAL:%.*]] = getelementptr inbounds {{.*}}, [[AMEM:.*]], i32 0, i32 0
-     // CHECK-DAG: [[BVAL:%.*]] = getelementptr inbounds {{.*}}, [[BMEM:.*]], i32 0, i32 0
-     // CHECK-DAG: #dbg_declare(ptr [[AADDR]], ![[AARG:.*]], !DIExpression(), ![[ALOC]]
-     // CHECK-DAG: #dbg_declare(ptr [[BADDR]], ![[BARG:.*]], !DIExpression()
-     // CHECK-DAG: ![[AARG]] = !DILocalVariable(name: "a", arg: 1
-     // CHECK-DAG: ![[BARG]] = !DILocalVariable(name: "b", arg: 2
-     if b != 0 {
-       // CHECK-DAG: !DILexicalBlock({{.*}} line: [[@LINE-1]]
-       // Transparent inlined multiply:
-       // CHECK-DAG: smul{{.*}}, !dbg ![[MUL:[0-9]+]]
-       // CHECK-DAG: [[MUL]] = !DILocation(line: [[@LINE+1]],
-       return a*b
-     } else {
-       // CHECK-DAG: ![[PARENT:[0-9]+]] = distinct !DILexicalBlock({{.*}} line: [[@LINE-1]]
-       // CHECK-DAG: ![[VARSCOPE:[0-9]+]] = distinct !DILexicalBlock({{.*}} line: [[@LINE+1]]
-       var c: Int64 = 42
-       // CHECK-DAG: ![[CONDITION:[0-9]+]] = distinct !DILexicalBlock(scope: ![[VARSCOPE]], {{.*}}, line: [[@LINE+1]]
-       if a == 0 {
-         // CHECK-DAG: !DILexicalBlock(scope: ![[CONDITION]], {{.*}}, line: [[@LINE-1]]
-         // What about a nested scope?
-         return 0
-       }
-       return c
-     }
-}
-
-// CHECK-DAG: ![[MAINFILE:[0-9]+]] = !DIFile(filename: "{{.*}}DebugInfo/basic.swift", directory: "{{.*}}")
-// CHECK-DAG: !DICompileUnit(language: DW_LANG_Swift, file: ![[MAINFILE]],{{.*}} producer: "{{.*}}Swift version{{.*}},{{.*}}
-// CHECK-DAG: !DISubprogram(name: "main", {{.*}}file: ![[MAINFILE]],
-
-// Function type for foo.
-// CHECK-DAG: ![[FOOTYPE]] = !DISubroutineType(types: ![[PARAMTYPES:[0-9]+]])
-// CHECK-DAG: ![[INT64:.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "Int64", {{.*}}, identifier: "$ss5Int64VD")
-// CHECK-DAG: ![[PARAMTYPES]] = !{![[INT64]], ![[INT64]], ![[INT64]]}
-// Import of the main module with the implicit name.
-// CHECK-DAG: !DIImportedEntity(tag: DW_TAG_imported_module, scope: ![[MAINFILE]], entity: ![[MAINMODULE:[0-9]+]], file: ![[MAINFILE]])
-// CHECK-DAG: ![[MAINMODULE]] = !DIModule({{.*}}, name: "basic"
-
-// DWARF Version
-// DWARF-CHECK-DAG:  i32 7, !"Dwarf Version", i32 4}
-// CV-CHECK-DAG: i32 2, !"CodeView", i32 1}
-
-// Debug Info Version
-// CHECK-DAG:  i32 2, !"Debug Info Version", i32
+public func foo() -> Int {
+  let bar = 1
+  return bar
+}
\ No newline at end of file
diff --git a/test/DebugInfo/basic_windows.swift b/test/DebugInfo/basic_windows.swift
new file mode 100644
index 0000000000000..e2195b08a1c12
--- /dev/null
+++ b/test/DebugInfo/basic_windows.swift
@@ -0,0 +1,17 @@
+// A basic test for debug info.
+// REQUIRES: OS=windows-msvc
+// --------------------------------------------------------------------
+// Verify that, by default, we exactly emit 1 DICompileUnit entry without dwoId.
+// On Windows, we always emit minimal DebugInfo to match MSVC's behavior:
+// See https://github.com/llvm/llvm-project/pull/142970 for more details.
+// RUN: %target-swift-frontend %s -emit-ir -o - \
+// RUN:   | %FileCheck %s --check-prefix NDEBUG
+// NDEBUG: source_filename
+// NDEBUG: !DICompileUnit(
+// NDEBUG-NOT: dwoId:
+// NDEBUG-SAME: )
+// NDEBUG-NOT: !DICompileUnit(
+public func foo() -> Int {
+  let bar = 1
+  return bar
+}
diff --git a/test/DebugInfo/debug_fragment_merge.swift b/test/DebugInfo/debug_fragment_merge.swift
index 0bf88d60cc516..9824862905503 100644
--- a/test/DebugInfo/debug_fragment_merge.swift
+++ b/test/DebugInfo/debug_fragment_merge.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -primary-file %s -Xllvm -sil-print-types -emit-sil -O -g | %FileCheck %s --check-prefix CHECK-SIL
-// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -primary-file %s -emit-irgen -O -g | %FileCheck %s
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -primary-file %s -Xllvm -sil-print-types -Xllvm -sil-disable-pass=temp-lvalue-elimination -emit-sil -O -g | %FileCheck %s --check-prefix CHECK-SIL
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -primary-file %s -Xllvm -sil-disable-pass=temp-lvalue-elimination -emit-irgen -O -g | %FileCheck %s
 
 // REQUIRES: CPU=arm64 || CPU=x86_64 || CPU=arm64e
 
diff --git a/test/DebugInfo/debug_scope_distinct.swift b/test/DebugInfo/debug_scope_distinct.swift
index c7221bb608281..6dfc157670ebf 100644
--- a/test/DebugInfo/debug_scope_distinct.swift
+++ b/test/DebugInfo/debug_scope_distinct.swift
@@ -12,14 +12,14 @@
 //
 // CHECK: %[[ARG0:.*]] = load {{.*}} %[[ARG_PTR]]
 // CHECK: #dbg_value({{.*}} %[[ARG0]], ![[VAR1:[0-9]+]], !DIExpression(DW_OP_LLVM_fragment, 0, 64), ![[LOC1:[0-9]+]]
-// CHECK: %[[ARG1_GEP:.*]] = getelementptr inbounds i8, ptr %[[ARG_PTR]], i64 8
+// CHECK: %[[ARG1_GEP:.*]] = getelementptr inbounds{{.*}} i8, ptr %[[ARG_PTR]], i64 8
 // CHECK: %[[ARG1:.*]] = load {{.*}} %[[ARG1_GEP]]
 // CHECK: #dbg_value({{.*}} %[[ARG1]], ![[VAR1]], !DIExpression(DW_OP_LLVM_fragment, 64, 8), ![[LOC1]]
 //
-// CHECK: %[[ARG2_GEP:.*]] = getelementptr inbounds i8, ptr %[[ARG_PTR]], i64 32
+// CHECK: %[[ARG2_GEP:.*]] = getelementptr inbounds{{.*}} i8, ptr %[[ARG_PTR]], i64 32
 // CHECK: %[[ARG2:.*]] = load {{.*}} %[[ARG2_GEP]]
 // CHECK: #dbg_value({{.*}} %[[ARG2]], ![[VAR1]], !DIExpression(DW_OP_LLVM_fragment, 0, 64), ![[LOC2:[0-9]+]]
-// CHECK: %[[ARG3_GEP:.*]] = getelementptr inbounds i8, ptr %[[ARG_PTR]], i64 40
+// CHECK: %[[ARG3_GEP:.*]] = getelementptr inbounds{{.*}} i8, ptr %[[ARG_PTR]], i64 40
 // CHECK: %[[ARG3:.*]] = load {{.*}} %[[ARG3_GEP]]
 // CHECK: #dbg_value({{.*}} %[[ARG3]], ![[VAR1]], !DIExpression(DW_OP_LLVM_fragment, 64, 8), ![[LOC2]]
 
diff --git a/test/DebugInfo/generic_arg4.swift b/test/DebugInfo/generic_arg4.swift
index fb3dcefd16e69..36acf634362b9 100644
--- a/test/DebugInfo/generic_arg4.swift
+++ b/test/DebugInfo/generic_arg4.swift
@@ -9,7 +9,7 @@ public struct Q<T> {
 // CHECK-SAME:       ![[ARG:.*]], !DIExpression()
 // CHECK: store ptr %0, ptr %[[ALLOCA]], align
 // No deref here: the array argument is passed by value.
-// CHECK: ![[DITY:.*]] = !DICompositeType({{.*}}name: "$sSay12generic_arg41QVyxGGD"
+// CHECK: ![[DITY:.*]] = !DICompositeType({{.*}}identifier: "$sSay12generic_arg41QVyxGGD"
 public func foo<T>(_ arg: [Q<T>]) {
 // CHECK: ![[ARG]] = !DILocalVariable(name: "arg", arg: 1,
 // CHECK-SAME:                        line: [[@LINE-2]], type: ![[DITY:.*]])
diff --git a/test/DebugInfo/generic_arg5.swift b/test/DebugInfo/generic_arg5.swift
index ded6a3c3ae7bb..7f9a5efb194d0 100644
--- a/test/DebugInfo/generic_arg5.swift
+++ b/test/DebugInfo/generic_arg5.swift
@@ -12,7 +12,7 @@ public func foo<Type>(_ values : [S<Type>])
   // CHECK-SAME:       ![[ARG:[0-9]+]],
   // CHECK-SAME:       !DIExpression(DW_OP_deref)
   // CHECK: store ptr %1, ptr %[[ALLOCA]], align
-  // CHECK-DAG: ![[TYP:[0-9]+]] = !DICompositeType({{.*}}, name: "$s12generic_arg51SVyxGD"
+  // CHECK-DAG: ![[TYP:[0-9]+]] = !DICompositeType({{.*}}, identifier: "$s12generic_arg51SVyxGD"
   // The argument is a by-ref struct and thus needs to be dereferenced.
   // CHECK-DAG: ![[ARG]] = !DILocalVariable(name: "arg", arg: 1,{{.*}}line: [[@LINE+6]],{{.*}} type: ![[LET_TYP:[0-9]+]])
   // CHECK-DAG: ![[LET_TYP]] = !DIDerivedType(tag: DW_TAG_const_type,{{.*}} baseType: ![[TYP_CONTAINER:[0-9]+]])
diff --git a/test/DebugInfo/global_opaque_var.swift b/test/DebugInfo/global_opaque_var.swift
new file mode 100644
index 0000000000000..0cd49086dba3c
--- /dev/null
+++ b/test/DebugInfo/global_opaque_var.swift
@@ -0,0 +1,32 @@
+// RUN: %target-swift-frontend -primary-file %s -emit-ir -g -o - | %FileCheck %s
+
+public protocol TheProtocol {}
+
+public class TheClass: TheProtocol {
+}
+
+struct TheStruct<T> {
+  let t: T
+}
+
+func f() -> some TheProtocol {
+  let p: some TheProtocol = TheClass()
+  return p
+}
+
+let v = f()
+// CHECK: !DIGlobalVariable(name: "v", {{.*}}type: ![[FIXED_BUFFER:[0-9]+]]
+// CHECK: ![[FIXED_BUFFER]] = !DICompositeType(tag: DW_TAG_structure_type, name: "$swift.fixedbuffer", {{.*}}, elements: ![[TYPE_1:[0-9]+]]
+// CHECK: ![[TYPE_1]] = !{![[TYPE_2:[0-9]+]]}
+// CHECK: ![[TYPE_2]] = !DIDerivedType(tag: DW_TAG_member, name: "contents"{{.*}}baseType: ![[TYPE_3:[0-9]+]]
+// CHECK: ![[TYPE_3]] = !DIDerivedType(tag: DW_TAG_const_type, baseType: ![[TYPE:[0-9]+]])
+// CHECK: ![[TYPE]] = !DICompositeType(tag: DW_TAG_structure_type, name: "TheClass"
+
+
+let v2 = TheStruct(t: f())
+// CHECK: !DIGlobalVariable(name: "v2", {{.*}}type: ![[CONST_TYPE_GEN:[0-9]+]]
+// CHECK: ![[CONST_TYPE_GEN]] = !DIDerivedType(tag: DW_TAG_const_type, baseType: ![[TYPE_GEN_1:[0-9]+]])
+// CHECK: ![[TYPE_GEN_1]] = !DICompositeType(tag: DW_TAG_structure_type{{.*}}elements: ![[TYPE_GEN_2:[0-9]+]]
+// CHECK: ![[TYPE_GEN_2]] = !{![[TYPE_GEN_3:[0-9]+]]}
+// CHECK: ![[TYPE_GEN_3]] = !DIDerivedType(tag: DW_TAG_member{{.*}}baseType: ![[TYPE_GEN:[0-9]+]]
+// CHECK: ![[TYPE_GEN]] = !DICompositeType(tag: DW_TAG_structure_type, name: "$s17global_opaque_var9TheStructVyAA0D5ClassCGD"
diff --git a/test/DebugInfo/guard-let-scope4.swift b/test/DebugInfo/guard-let-scope4.swift
index d404d8ca1e88c..22f36d691dddb 100644
--- a/test/DebugInfo/guard-let-scope4.swift
+++ b/test/DebugInfo/guard-let-scope4.swift
@@ -1,13 +1,14 @@
 // RUN: %target-swift-frontend -g -Xllvm -sil-print-types -emit-sil %s -parse-as-library -module-name a | %FileCheck %s
+// RUN: %target-swift-frontend -g -Xllvm -sil-print-types -emit-sil %s -parse-as-library -module-name a -enable-upcoming-feature ImmutableWeakCaptures | %FileCheck %s --check-prefixes=CHECK,CHECK-HAS-WEAK-LET
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 open class C {
-  public func fun() {}
-
   public func run() {
     { [weak self] in
       guard let self else { fatalError("cannot happen") }
       // CHECK: sil_scope [[LAMBDA:[0-9]+]] { loc "{{.*}}":6:5
       // CHECK: sil_scope [[BODY:[0-9]+]] { loc "{{.*}}":6:19 parent [[LAMBDA]]
       // CHECK: sil_scope [[LET:[0-9]+]] { loc "{{.*}}":7:7 parent [[BODY]]
+      // CHECK-HAS-WEAK-LET: sil_scope [[TMP:[0-9]+]] { loc "{{.*}}":7:17 parent [[LET]]
       // CHECK: sil_scope [[GUARD:[0-9]+]] { loc "{{.*}}":7:17 parent [[LET]]
       // CHECK: debug_value {{.*}} : $C, let, name "self", {{.*}}, scope [[GUARD]]
       // CHECK: function_ref {{.*}}3fun{{.*}}, scope [[GUARD]]
@@ -15,4 +16,8 @@ open class C {
       self.fun()
     }()
   }
+  public func fun() {}
 }
+
+
+
diff --git a/test/DebugInfo/move_function_dbginfo_async.swift b/test/DebugInfo/move_function_dbginfo_async.swift
index 693c0934d3eb4..f1811b3672edf 100644
--- a/test/DebugInfo/move_function_dbginfo_async.swift
+++ b/test/DebugInfo/move_function_dbginfo_async.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -parse-as-library -target %target-swift-5.1-abi-triple -g -emit-sil -o - %s | %FileCheck -check-prefix=SIL %s
-// RUN: %target-swift-frontend -parse-as-library -target %target-swift-5.1-abi-triple -g -emit-ir -o - %s | %FileCheck %s
-// RUN: %target-swift-frontend -parse-as-library -target %target-swift-5.1-abi-triple -g -c %s -o %t/out.o
+// RUN: %target-swift-frontend -parse-as-library -target %target-swift-5.1-abi-triple -Xllvm -sil-disable-pass=mandatory-temp-rvalue-elimination -g -emit-sil -o - %s | %FileCheck -check-prefix=SIL %s
+// RUN: %target-swift-frontend -parse-as-library -target %target-swift-5.1-abi-triple -Xllvm -sil-disable-pass=mandatory-temp-rvalue-elimination -g -emit-ir -o - %s | %FileCheck %s
+// RUN: %target-swift-frontend -parse-as-library -target %target-swift-5.1-abi-triple -Xllvm -sil-disable-pass=mandatory-temp-rvalue-elimination -g -c %s -o %t/out.o
 
 // This test checks that:
 //
diff --git a/test/DebugInfo/nested_opaque.swift b/test/DebugInfo/nested_opaque.swift
new file mode 100644
index 0000000000000..7fd85fc7988fe
--- /dev/null
+++ b/test/DebugInfo/nested_opaque.swift
@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend -primary-file %s -emit-ir -g -o - | %FileCheck %s
+
+protocol TheProtocol {
+}
+
+// CHECK: ![[FUNC_ID:[0-9]+]] = distinct !DISubprogram(name: "theFunction", 
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "TheType", scope: ![[FUNC_ID]]
+func theFunction() -> some TheProtocol {
+    struct TheType: TheProtocol {
+    }
+    return TheType()
+}
+
+theFunction()
diff --git a/test/DebugInfo/nonisolated_nonsending.swift b/test/DebugInfo/nonisolated_nonsending.swift
new file mode 100644
index 0000000000000..fab39905c3b88
--- /dev/null
+++ b/test/DebugInfo/nonisolated_nonsending.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend -emit-ir -g %s -swift-version 6 -enable-upcoming-feature NonisolatedNonsendingByDefault
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+public protocol P: Sendable {
+  func f(_: Int) async
+}
+
+public struct S: Sendable {
+  public func f(p: [any P]) async {
+    let x: [@Sendable (Int) async -> ()] = p.map { $0.f }
+
+    // FIXME: crashes
+    //let y = p.map { $0.f }
+  }
+}
diff --git a/test/DebugInfo/optimizer_pipeline.swift b/test/DebugInfo/optimizer_pipeline.swift
index 8071848bbd2c2..ed5ba13c890b6 100644
--- a/test/DebugInfo/optimizer_pipeline.swift
+++ b/test/DebugInfo/optimizer_pipeline.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend %s -emit-sil -g -Osize -parse-stdlib -parse-as-library -enable-ossa-modules -o - | %FileCheck %s
+// RUN: %target-swift-frontend %s -emit-sil -g -Osize -parse-stdlib -parse-as-library -o - | %FileCheck %s
 
 // REQUIRES: asserts
 
diff --git a/test/DebugInfo/parameterized_existential_composition.swift b/test/DebugInfo/parameterized_existential_composition.swift
new file mode 100644
index 0000000000000..4d884772f5f38
--- /dev/null
+++ b/test/DebugInfo/parameterized_existential_composition.swift
@@ -0,0 +1,67 @@
+// RUN: %target-swift-frontend -emit-ir %s -g -target %target-swift-5.9-abi-triple
+
+// Note: The goal of this test is to exercise the mangling/demangling via
+// the -g flag.
+
+public protocol P<A, B> {
+  associatedtype A
+  associatedtype B
+}
+
+public protocol P1<A> {
+  associatedtype A
+}
+
+public protocol Q<C> {
+  associatedtype C
+}
+
+public protocol R {}
+
+public class C<T: Equatable> {}
+
+public func foo(_ a: any P<Int, Float> & R) {}
+public func foo(_ a: any P<Int, Float> & Q<String>) {}
+public func foo(_ a: any P<Int, Float> & Q<String> & R) {}
+public func foo(_ a: any P<Int, Float> & Q<String> & R & C<Bool>) {}
+public func foo(_ a: any P<Int, Float> & Q<String> & R & AnyObject) {}
+
+public func foo(_ a: any (P<Int, Float> & R).Type) {}
+public func foo(_ a: any (P<Int, Float> & Q<String>).Type) {}
+public func foo(_ a: any (P<Int, Float> & Q<String> & R).Type) {}
+public func foo(_ a: any (P<Int, Float> & Q<String> & R & C<Bool>).Type) {}
+public func foo(_ a: any (P<Int, Float> & Q<String> & R & AnyObject).Type) {}
+
+public func foo(_ a: (any P<Int, Float> & R).Type) {}
+public func foo(_ a: (any P<Int, Float> & Q<String>).Type) {}
+public func foo(_ a: (any P<Int, Float> & Q<String> & R).Type) {}
+public func foo(_ a: (any P<Int, Float> & Q<String> & R & C<Bool>).Type) {}
+public func foo(_ a: (any P<Int, Float> & Q<String> & R & AnyObject).Type) {}
+
+public func foo(_ a: (any P & P1).Type) {}
+public func foo(_ a: (any P & P1<String>).Type) {}
+public func foo(_ a: (any P & P1<String> & R).Type) {}
+public func foo(_ a: (any P & P1<String> & R & C<Bool>).Type) {}
+public func foo(_ a: (any P & P1<String> & R & AnyObject).Type) {}
+
+public func foo(_ a: (any P<Int, Float> & P1).Type) {}
+public func foo(_ a: (any P<Int, Float> & P1 & R).Type) {}
+public func foo(_ a: (any P<Int, Float> & P1 & R & C<Bool>).Type) {}
+public func foo(_ a: (any P<Int, Float> & P1 & R & AnyObject).Type) {}
+
+public protocol Q2<C>: Q {}
+
+public protocol Q3<C>: Q {
+  associatedtype C
+}
+
+public func foo(_ a: (any Q2<Int> & R).Type) {}
+public func foo(_ a: (any Q3<Int> & R).Type) {}
+public func foo(_ a: (any Q2 & Q3).Type) {}
+public func foo(_ a: (any Q2 & Q3<Int>).Type) {}
+public func foo2(_ a: (any Q2<Int> & Q3).Type) {}
+public func foo3(_ a: (any Q2<Int> & Q3<Int>).Type) {}
+
+public struct Foo<each T, U> {
+  public var a1: (repeat any P<each T, U> & R)
+}
diff --git a/test/DebugInfo/shadowcopy-linetable.swift b/test/DebugInfo/shadowcopy-linetable.swift
index a5647a24fa9ef..493d0cb8d7e62 100644
--- a/test/DebugInfo/shadowcopy-linetable.swift
+++ b/test/DebugInfo/shadowcopy-linetable.swift
@@ -24,7 +24,7 @@ func foo(_ x: inout Int64) {
   // IRCHECK-NEXT: call void @llvm.memset.{{.*}}(ptr align {{(4|8)}} %[[X]], i8 0
   // IRCHECK: store ptr %0, ptr %[[X]], align {{(4|8)}}
   // IRCHECK-SAME: !dbg ![[LOC0:.*]]
-  // IRCHECK-NEXT: %[[VALUE:.*]] = getelementptr inbounds %Ts5Int64V, ptr %0, i32 0, i32 0,
+  // IRCHECK-NEXT: %[[VALUE:.*]] = getelementptr inbounds{{.*}} %Ts5Int64V, ptr %0, i32 0, i32 0,
   // IRCHECK-SAME: !dbg ![[LOCLOAD:.*]]
   // IRCHECK-NEXT: load i64, ptr %[[VALUE]], align {{(4|8)}}
   // IRCHECK-SAME: !dbg ![[LOCLOAD]]
diff --git a/test/DebugInfo/simplify_checked_cast_br.sil b/test/DebugInfo/simplify_checked_cast_br.sil
index 89cd3ad2dfc02..5515c23511800 100644
--- a/test/DebugInfo/simplify_checked_cast_br.sil
+++ b/test/DebugInfo/simplify_checked_cast_br.sil
@@ -13,9 +13,9 @@ class X : B {}
 // CHECK:         %0 = alloc_ref
 // CHECK-NEXT:  checked_cast_br X in %0 : $X
 // CHECK:     bb2([[A:%.*]] : @owned $X):
-// CHECK-NEXT:  [[U:%.*]] = upcast [[A]] : $X to $B, loc "takethis":1:1
-// CHECK-NEXT:  [[E:%.*]] = init_existential_ref [[U]] {{.+}}, loc "takethis":1:1
-// CHECK-NEXT:  debug_value [[E]] : $AnyObject, let, name "me", loc "ignore-this-meta-inst":1:1
+// CHECK-NEXT:  [[U:%.*]] = upcast [[A]] : $X to $B, loc "dv":1:1
+// CHECK-NEXT:  [[E:%.*]] = init_existential_ref [[U]] {{.+}}, loc "dv":1:1
+// CHECK-NEXT:  debug_value [[E]] : $AnyObject, let, name "me", loc "dv":1:1
 // CHECK-NEXT:  destroy_value [[E]] : $AnyObject, loc "takethis":1:1
 // CHECK:       } // end sil function 'test_ossa'
 sil [ossa] @test_ossa : $@convention(thin) () -> @owned X {
@@ -30,7 +30,7 @@ bb1(%5 : @owned $X):
   return %5 : $X
 
 bb2(%7 : @owned $AnyObject):
-  debug_value %7 : $AnyObject, let, name "me", loc "ignore-this-meta-inst":1:1
+  debug_value %7 : $AnyObject, let, name "me", loc "dv":1:1
   destroy_value %7: $AnyObject, loc "takethis":1:1
   unreachable
 }
diff --git a/test/DebugInfo/struct_resilience.swift b/test/DebugInfo/struct_resilience.swift
index cb61989359983..34a28a4c11e51 100644
--- a/test/DebugInfo/struct_resilience.swift
+++ b/test/DebugInfo/struct_resilience.swift
@@ -29,7 +29,7 @@ public func f() {
   // CHECK: store ptr %[[S1]], ptr %[[ADDR]]
 }
 
-// CHECK: ![[TY:[0-9]+]] = !DICompositeType(tag: DW_TAG_structure_type, name: "$s16resilient_struct4SizeVD",
+// CHECK: ![[TY:[0-9]+]] = !DICompositeType(tag: DW_TAG_structure_type, name: "Size",
 // CHECK: ![[LET_TY:[0-9]+]] = !DIDerivedType(tag: DW_TAG_const_type,
 // CHECK-SAME:                                baseType: ![[TY:[0-9]+]])
 // CHECK: ![[V1]] = !DILocalVariable(name: "s1", {{.*}}type: ![[LET_TY]])
diff --git a/test/DebugInfo/sugar_inline_array.swift b/test/DebugInfo/sugar_inline_array.swift
index 30072aea303d9..7e8423f4bf1d2 100644
--- a/test/DebugInfo/sugar_inline_array.swift
+++ b/test/DebugInfo/sugar_inline_array.swift
@@ -1,15 +1,13 @@
-// RUN: %target-swift-frontend %s -emit-ir -enable-experimental-feature InlineArrayTypeSugar -disable-availability-checking -g -o - | %FileCheck %s
+// RUN: %target-swift-frontend %s -emit-ir -disable-availability-checking -g -o - | %FileCheck %s
 
-// REQUIRES: swift_feature_InlineArrayTypeSugar
-
-let a: ([3 x Int], InlineArray<3, Int>) = ([1, 2, 3], [1, 2, 3])
-let b: ([3 x [1 x String]], InlineArray<3, InlineArray<1, String>>) = ([[""], [""], [""]], [[""], [""], [""]])
+let a: ([3 of Int], InlineArray<3, Int>) = ([1, 2, 3], [1, 2, 3])
+let b: ([3 of [1 of String]], InlineArray<3, InlineArray<1, String>>) = ([[""], [""], [""]], [[""], [""], [""]])
 
 // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "$s$2_SiXSA_s11InlineArrayVy$2_SiGtD", {{.*}})
 // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "$s$2_$0_SSXSAXSA_s11InlineArrayVy$2_ABy$0_SSGGtD", {{.*}})
 
 // RUN: swift-demangle 's$2_SiXSA_s11InlineArrayVy$2_SiGtD' | %FileCheck %s --check-prefix SIMPLE
-// SIMPLE: ([3 x Swift.Int], Swift.InlineArray<3, Swift.Int>)
+// SIMPLE: ([3 of Swift.Int], Swift.InlineArray<3, Swift.Int>)
 
 // RUN: swift-demangle 's$2_$0_SSXSAXSA_s11InlineArrayVy$2_ABy$0_SSGGtD' | %FileCheck %s --check-prefix NESTED
-// NESTED: ([3 x [1 x Swift.String]], Swift.InlineArray<3, Swift.InlineArray<1, Swift.String>>)
+// NESTED: ([3 of [1 of Swift.String]], Swift.InlineArray<3, Swift.InlineArray<1, Swift.String>>)
diff --git a/test/DebugInfo/typealias.swift b/test/DebugInfo/typealias.swift
index 993cf2fa14e76..7942c96cbd20f 100644
--- a/test/DebugInfo/typealias.swift
+++ b/test/DebugInfo/typealias.swift
@@ -120,10 +120,11 @@ public protocol Down {
 }
 
 public typealias DependentAlias<T : Up> = T.A.A
+// CHECK-DAG: ![[DEPENDENTALIAS:.*]] = !DIDerivedType(tag: DW_TAG_typedef, name: "DependentAlias", {{.*}} baseType: ![[INTTYPE]])
 
 extension Up where A.A == Int {
   public func foo() {
-    // CHECK-DAG: !DILocalVariable(name: "gg",{{.*}} type: ![[INTTYPE]]
+    // CHECK-DAG: !DILocalVariable(name: "gg",{{.*}} type: ![[DEPENDENTALIAS]]
     var gg: DependentAlias<Self> = 123
   }
 }
diff --git a/test/DebugInfo/weak-self-capture.swift b/test/DebugInfo/weak-self-capture.swift
index 600ddbff0bb54..0daf9a8309480 100644
--- a/test/DebugInfo/weak-self-capture.swift
+++ b/test/DebugInfo/weak-self-capture.swift
@@ -1,4 +1,8 @@
 // RUN: %target-swift-frontend %s -emit-ir -g -o - | %FileCheck %s
+// RUN: %target-swift-frontend %s -enable-upcoming-feature ImmutableWeakCaptures -emit-ir -g -o - | %FileCheck %s
+
+// REQUIRES: swift_feature_ImmutableWeakCaptures
+
 public class ClosureMaker {
     var a : Int
 
diff --git a/test/Demangle/Inputs/manglings.txt b/test/Demangle/Inputs/manglings.txt
index 4818f9a2808fc..13f135910eed0 100644
--- a/test/Demangle/Inputs/manglings.txt
+++ b/test/Demangle/Inputs/manglings.txt
@@ -262,6 +262,7 @@ _$Ss17MutableCollectionP1asAARzs012RandomAccessB0RzsAA11SubSequences013Bidirecti
 _T03foo4_123ABTf3psbpsb_n ---> function signature specialization <Arg[0] = [Constant Propagated String : u8'123'], Arg[1] = [Constant Propagated String : u8'123']> of foo
 _T04main5innerys5Int32Vz_yADctF25closure_with_box_argumentxz_Bi32__lXXTf1nc_n ---> function signature specialization <Arg[1] = [Closure Propagated : closure_with_box_argument, Argument Types : [<A> { var A } <Builtin.Int32>]> of main.inner(inout Swift.Int32, (Swift.Int32) -> ()) -> ()
 _$S4main5inneryys5Int32Vz_yADctF25closure_with_box_argumentxz_Bi32__lXXTf1nc_n ---> function signature specialization <Arg[1] = [Closure Propagated : closure_with_box_argument, Argument Types : [<A> { var A } <Builtin.Int32>]> of main.inner(inout Swift.Int32, (Swift.Int32) -> ()) -> ()
+$s3foo7closureSSTf1cC0_n ---> function signature specialization <Arg[0] = [Closure Propagated : closure, Argument Types : [Swift.String], Arg[1] = [Same As Argument 0]> of foo
 _T03foo6testityyyc_yyctF1a1bTf3pfpf_n ---> function signature specialization <Arg[0] = [Constant Propagated Function : a], Arg[1] = [Constant Propagated Function : b]> of foo.testit(() -> (), () -> ()) -> ()
 _$S3foo6testityyyyc_yyctF1a1bTf3pfpf_n ---> function signature specialization <Arg[0] = [Constant Propagated Function : a], Arg[1] = [Constant Propagated Function : b]> of foo.testit(() -> (), () -> ()) -> ()
 _SocketJoinOrLeaveMulticast ---> _SocketJoinOrLeaveMulticast
@@ -298,6 +299,8 @@ _T0SqWOC ---> outlined init with copy of Swift.Optional
 _T0SqWOD ---> outlined assign with take of Swift.Optional
 _T0SqWOF ---> outlined assign with copy of Swift.Optional
 _T0SqWOH ---> outlined destroy of Swift.Optional
+_T0SqWOB ---> outlined init with take of Swift.Optional
+_T0SqWOb ---> outlined init with take of Swift.Optional
 _T03nix6testitSaySiGyFTv_ ---> outlined variable #0 of nix.testit() -> [Swift.Int]
 _T03nix6testitSaySiGyFTv_r ---> outlined read-only object #0 of nix.testit() -> [Swift.Int]
 _T03nix6testitSaySiGyFTv0_ ---> outlined variable #1 of nix.testit() -> [Swift.Int]
@@ -375,6 +378,8 @@ $s18resilient_protocol24ResilientDerivedProtocolPxAA0c4BaseE0Tn --> associated c
 $s3red4testyAA3ResOyxSayq_GAEs5ErrorAAq_sAFHD1__HCg_GADyxq_GsAFR_r0_lF ---> red.test<A, B where B: Swift.Error>(red.Res<A, B>) -> red.Res<A, [B]>
 $s3red4testyAA7OurTypeOy4them05TheirD0Vy5AssocQzGAjE0F8ProtocolAAxAA0c7DerivedH0HD1_AA0c4BaseH0HI1_AieKHA2__HCg_GxmAaLRzlF ---> red.test<A where A: red.OurDerivedProtocol>(A.Type) -> red.OurType<them.TheirType<A.Assoc>>
 $s17property_wrappers10WithTuplesV9fractionsSd_S2dtvpfP ---> property wrapper backing initializer of property_wrappers.WithTuples.fractions : (Swift.Double, Swift.Double, Swift.Double)
+$s16property_wrapper8MyStructV1xSivpfF ---> property wrapped field init accessor of property_wrapper.MyStruct.x : Swift.Int
+$s4main6myFuncyyF1xL_SivpfF ---> property wrapped field init accessor of x #1 : Swift.Int in main.myFunc() -> ()
 $sSo17OS_dispatch_queueC4sync7executeyyyXE_tFTOTA ---> {T:$sSo17OS_dispatch_queueC4sync7executeyyyXE_tFTO} partial apply forwarder for @nonobjc __C.OS_dispatch_queue.sync(execute: () -> ()) -> ()
 $s4main1gyySiXCvp ---> main.g : @convention(c) (Swift.Int) -> ()
 $s4main1gyySiXBvp ---> main.g : @convention(block) (Swift.Int) -> ()
@@ -420,6 +425,7 @@ $s4test3fooyyS2f_SfYkztYjrXEF ---> test.foo(@differentiable(reverse) (Swift.Floa
 $s4test3fooyyS2f_SfYkntYjrXEF ---> test.foo(@differentiable(reverse) (Swift.Float, __owned @noDerivative Swift.Float) -> Swift.Float) -> ()
 $s4test3fooyyS2f_SfYktYjrXEF ---> test.foo(@differentiable(reverse) (Swift.Float, @noDerivative Swift.Float) -> Swift.Float) -> ()
 $s4test3fooyyS2f_SfYktYaYbYjrXEF ---> test.foo(@differentiable(reverse) @Sendable (Swift.Float, @noDerivative Swift.Float) async -> Swift.Float) -> ()
+$SSSTf4pd44444_n ---> function signature specialization <Arg[0] = [Constant Propagated Float : 44444]> of Swift.String
 $sScA ---> Swift.Actor
 $sScGySiG ---> Swift.TaskGroup<Swift.Int>
 $s4test10returnsOptyxycSgxyScMYccSglF ---> test.returnsOpt<A>((@Swift.MainActor () -> A)?) -> (() -> A)?
@@ -435,6 +441,7 @@ $s16distributed_test1XC7computeyS2iFTF ---> distributed accessor for distributed
 $s27distributed_actor_accessors7MyActorC7simple2ySSSiFTETFHF ---> accessible function runtime record for distributed accessor for distributed thunk distributed_actor_accessors.MyActor.simple2(Swift.Int) -> Swift.String
 $s1A3bar1aySSYt_tF ---> A.bar(a: _const Swift.String) -> ()
 $s1t1fyyFSiAA3StrVcs7KeyPathCyADSiGcfu_SiADcfu0_33_556644b740b1b333fecb81e55a7cce98ADSiTf3npk_n ---> function signature specialization <Arg[1] = [Constant Propagated KeyPath : _556644b740b1b333fecb81e55a7cce98<t.Str,Swift.Int>]> of implicit closure #2 (t.Str) -> Swift.Int in implicit closure #1 (Swift.KeyPath<t.Str, Swift.Int>) -> (t.Str) -> Swift.Int in t.f() -> ()
+$s3foo4main1SVs5Int32VSbTf3npSSi3Si0_n ---> function signature specialization <Arg[1] = [Constant Propagated Struct : main.S][Constant Propagated Struct : Swift.Int32][Constant Propagated Integer : 3][Constant Propagated Struct : Swift.Bool][Constant Propagated Integer : 0]> of foo
 $s21back_deploy_attribute0A12DeployedFuncyyFTwb ---> back deployment thunk for back_deploy_attribute.backDeployedFunc() -> ()
 $s21back_deploy_attribute0A12DeployedFuncyyFTwB ---> back deployment fallback for back_deploy_attribute.backDeployedFunc() -> ()
 $s4test3fooyyAA1P_px1TRts_XPlF ---> test.foo<A>(any test.P<Self.T == A>) -> ()
@@ -487,7 +494,7 @@ $s3red7MyActorC3runyxxyYaKACYcYTXEYaKlFZ ---> static red.MyActor.run<A>(@red.MyA
 $s3red7MyActorC3runyxxyYaKYAYTXEYaKlFZ ---> static red.MyActor.run<A>(@isolated(any) () async throws -> sending A) async throws -> A
 $s7ToolKit10TypedValueOACs5Error_pIgHTnTrzo_A2CsAD_pIegHiTrzr_TR ---> {T:} reabstraction thunk helper from @callee_guaranteed @async (@in_guaranteed sending ToolKit.TypedValue) -> sending (@out ToolKit.TypedValue, @error @owned Swift.Error) to @escaping @callee_guaranteed @async (@in sending ToolKit.TypedValue) -> (@out ToolKit.TypedValue, @error @out Swift.Error)
 $s16sending_mangling16NonSendableKlassCACIegTiTr_A2CIegTxTo_TR ---> {T:} reabstraction thunk helper from @escaping @callee_guaranteed (@in sending sending_mangling.NonSendableKlass) -> sending (@out sending_mangling.NonSendableKlass) to @escaping @callee_guaranteed (@owned sending sending_mangling.NonSendableKlass) -> sending (@owned sending_mangling.NonSendableKlass)
-$s3red7MyActorC3runyxxyYaKYCXEYaKlFZ ---> static red.MyActor.run<A>(@execution(caller) () async throws -> A) async throws -> A
+$s3red7MyActorC3runyxxyYaKYCXEYaKlFZ ---> static red.MyActor.run<A>(nonisolated(nonsending) () async throws -> A) async throws -> A
 $s5thing1PP1sAA1SVvxTwc ---> coro function pointer to thing.P.s.modify2 : thing.S
 _$s15raw_identifiers0020foospace_liaADEDGcjayyF ---> raw_identifiers.`foo space`() -> ()
 _$s15raw_identifiers0018_3times_pgaIGJCFbhayyF ---> raw_identifiers.`3 times`() -> ()
@@ -496,3 +503,4 @@ _$s15raw_identifiers0020pathfoo_yuEHaaCiJskayyF ---> raw_identifiers.`path://foo
 _$s15raw_identifiers10FontWeightO009_100_FpEpdyyFZ ---> static raw_identifiers.FontWeight.`100`() -> ()
 $s7Library1BC1iSivxTwd ---> default override of Library.B.i.modify2 : Swift.Int
 $s7Library1BC1iSivxTwdTwc ---> coro function pointer to default override of Library.B.i.modify2 : Swift.Int
+$s3use1xAA3OfPVy3lib1GVyAA1fQryFQOyQo_GAjE1PAAxAeKHD1_AIHO_HCg_Gvp ---> use.x : use.OfP<lib.G<<<opaque return type of use.f() -> some>>.0>>
diff --git a/test/Distributed/Inputs/FakeDistributedActorSystems.swift b/test/Distributed/Inputs/FakeDistributedActorSystems.swift
index 4c073903d56fe..88fb8aca0cdb2 100644
--- a/test/Distributed/Inputs/FakeDistributedActorSystems.swift
+++ b/test/Distributed/Inputs/FakeDistributedActorSystems.swift
@@ -153,6 +153,80 @@ public struct FakeActorSystem: DistributedActorSystem, CustomStringConvertible {
   }
 }
 
+@available(SwiftStdlib 5.7, *)
+//@_spi(FakeDistributedActorSystems)
+public struct FakeActorSystemWithSPI: DistributedActorSystem, CustomStringConvertible {
+  public typealias ActorID = ActorAddress
+  public typealias InvocationDecoder = FakeInvocationDecoder
+  public typealias InvocationEncoder = FakeInvocationEncoder
+  public typealias SerializationRequirement = Codable
+  public typealias ResultHandler = FakeRoundtripResultHandler
+
+  // just so that the struct does not become "trivial"
+  let someValue: String = ""
+  let someValue2: String = ""
+  let someValue3: String = ""
+  let someValue4: String = ""
+
+  public init() {
+    print("Initialized new FakeActorSystem")
+  }
+
+  public func resolve<Act>(id: ActorID, as actorType: Act.Type) throws -> Act?
+      where Act: DistributedActor,
+      Act.ID == ActorID  {
+    nil
+  }
+
+  public func assignID<Act>(_ actorType: Act.Type) -> ActorID
+      where Act: DistributedActor,
+      Act.ID == ActorID {
+    ActorAddress(parse: "xxx")
+  }
+
+  public func actorReady<Act>(_ actor: Act)
+      where Act: DistributedActor,
+            Act.ID == ActorID {
+  }
+
+  public func resignID(_ id: ActorID) {
+  }
+
+  public func makeInvocationEncoder() -> InvocationEncoder {
+    .init()
+  }
+
+  public func remoteCall<Act, Err, Res>(
+      on actor: Act,
+      target: RemoteCallTarget,
+      invocation invocationEncoder: inout InvocationEncoder,
+      throwing: Err.Type,
+      returning: Res.Type
+  ) async throws -> Res
+    where Act: DistributedActor,
+          Act.ID == ActorID,
+          Err: Error,
+          Res: SerializationRequirement {
+    throw ExecuteDistributedTargetError(message: "\(#function) not implemented.")
+  }
+
+  public func remoteCallVoid<Act, Err>(
+    on actor: Act,
+    target: RemoteCallTarget,
+    invocation invocationEncoder: inout InvocationEncoder,
+    throwing: Err.Type
+  ) async throws
+    where Act: DistributedActor,
+          Act.ID == ActorID,
+          Err: Error {
+    throw ExecuteDistributedTargetError(message: "\(#function) not implemented.")
+  }
+
+  public nonisolated var description: Swift.String {
+    "\(Self.self)()"
+  }
+}
+
 @available(SwiftStdlib 5.7, *)
 public struct FakeNotLoadableAddressActorSystem: DistributedActorSystem, CustomStringConvertible {
   public typealias ActorID = NotLoadableActorAddress
diff --git a/test/Distributed/Macros/distributed_macro_expansion_DistributedProtocol_errors.swift b/test/Distributed/Macros/distributed_macro_expansion_DistributedProtocol_errors.swift
index 9d776369a5c47..fe1278ebba830 100644
--- a/test/Distributed/Macros/distributed_macro_expansion_DistributedProtocol_errors.swift
+++ b/test/Distributed/Macros/distributed_macro_expansion_DistributedProtocol_errors.swift
@@ -8,7 +8,7 @@
 // RUN: %empty-directory(%t-scratch)
 
 // RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-6.0-abi-triple %S/../Inputs/FakeDistributedActorSystems.swift
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-6.0-abi-triple -plugin-path %swift-plugin-dir -parse-as-library -I %t %S/../Inputs/FakeDistributedActorSystems.swift -dump-macro-expansions %s 2>&1
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -target %target-swift-6.0-abi-triple -plugin-path %swift-plugin-dir -parse-as-library -I %t %S/../Inputs/FakeDistributedActorSystems.swift -dump-macro-expansions %s 2>&1
 
 import Distributed
 
@@ -30,6 +30,14 @@ distributed actor Caplin {
 protocol Fail: DistributedActor {
   distributed func method() -> String
 }
+/*
+expected-expansion@-2:2{{
+  expected-error@1:19{{distributed actor '$Fail' does not declare ActorSystem it can be used with}}
+  expected-note@1:13{{you can provide a module-wide default actor system by declaring:}}
+  expected-error@1:19{{type '$Fail' does not conform to protocol 'DistributedActor'}}
+  expected-note@1:19{{add stubs for conformance}}
+}}
+*/
 
 @Resolvable // expected-note2{{in expansion of macro 'Resolvable' on protocol 'SomeRoot' here}}
 public protocol SomeRoot: DistributedActor, Sendable
@@ -39,3 +47,9 @@ public protocol SomeRoot: DistributedActor, Sendable
   static var staticValue: String { get }
   var value: String { get }
 }
+/*
+expected-expansion@-2:2{{
+  expected-error@1:27{{type '$SomeRoot<ActorSystem>' does not conform to protocol 'SomeRoot'}}
+  expected-note@1:27{{add stubs for conformance}}
+}}
+*/
diff --git a/test/Distributed/Macros/distributed_macro_expansion_DistributedProtocol_spi.swift b/test/Distributed/Macros/distributed_macro_expansion_DistributedProtocol_spi.swift
index 7164d1bac3800..d9ab6db57e2ae 100644
--- a/test/Distributed/Macros/distributed_macro_expansion_DistributedProtocol_spi.swift
+++ b/test/Distributed/Macros/distributed_macro_expansion_DistributedProtocol_spi.swift
@@ -7,9 +7,11 @@
 // RUN: %empty-directory(%t)
 // RUN: %empty-directory(%t-scratch)
 
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-6.0-abi-triple -plugin-path %swift-plugin-dir -I %t -dump-macro-expansions %s -dump-macro-expansions 2>&1 | %FileCheck %s
+// RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-6.0-abi-triple %S/../Inputs/FakeDistributedActorSystems.swift
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-6.0-abi-triple -plugin-path %swift-plugin-dir -parse-as-library -I %t -dump-macro-expansions %s -dump-macro-expansions 2>&1 | %FileCheck %s --dump-input=always
 
 import Distributed
+import FakeDistributedActorSystems
 
 @Resolvable
 @_spi(CoolFeatures)
@@ -36,3 +38,29 @@ public protocol Greeter: DistributedActor where ActorSystem: DistributedActorSys
 // CHECK-NEXT:     }
 // CHECK-NEXT:   }
 // CHECK-NEXT: }
+
+@_spi(DistributedSPIForTesting)
+@Resolvable
+public protocol GreeterWithSPISystem: DistributedActor where ActorSystem == FakeActorSystemWithSPI {
+  distributed func greet(name: String) -> String
+}
+
+// @Resolvable ->
+
+// CHECK: @_spi(DistributedSPIForTesting)
+// CHECK: public distributed actor $GreeterWithSPISystem: GreeterWithSPISystem,
+// CHECK-NEXT: Distributed._DistributedActorStub
+// CHECK-NEXT: {
+// CHECK:   public typealias ActorSystem = FakeActorSystemWithSPI
+// CHECK-NEXT: }
+
+// CHECK: @_spi(DistributedSPIForTesting)
+// CHECK: extension GreeterWithSPISystem where Self: Distributed._DistributedActorStub {
+// CHECK:       public distributed func greet(name: String) -> String {
+// CHECK-NEXT:     if #available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *) {
+// CHECK-NEXT:       Distributed._distributedStubFatalError()
+// CHECK-NEXT:     } else {
+// CHECK-NEXT:       fatalError()
+// CHECK-NEXT:     }
+// CHECK-NEXT:   }
+// CHECK-NEXT: }
diff --git a/test/Distributed/Runtime/distributed_actor_deinit.swift b/test/Distributed/Runtime/distributed_actor_deinit.swift
index 935ed891198eb..6c7784b4ac53e 100644
--- a/test/Distributed/Runtime/distributed_actor_deinit.swift
+++ b/test/Distributed/Runtime/distributed_actor_deinit.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -target %target-future-triple %import-libdispatch -parse-stdlib -parse-as-library -module-name=main %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out | %FileCheck %s
+// RUN: env %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: libdispatch
 // REQUIRES: executable_test
diff --git a/test/Distributed/Runtime/distributed_actor_func_calls_without_touching_returnType_metadata_first.swift b/test/Distributed/Runtime/distributed_actor_func_calls_without_touching_returnType_metadata_first.swift
index 781dd60f8fe9b..8afd936c8c4ef 100644
--- a/test/Distributed/Runtime/distributed_actor_func_calls_without_touching_returnType_metadata_first.swift
+++ b/test/Distributed/Runtime/distributed_actor_func_calls_without_touching_returnType_metadata_first.swift
@@ -1,8 +1,9 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-5.7-abi-triple %S/../Inputs/FakeDistributedActorSystems.swift
 // RUN: %target-build-swift -module-name dist -target %target-swift-5.7-abi-triple -parse-as-library -j2 -parse-as-library -plugin-path %swift-plugin-dir -I %t %s %S/../Inputs/FakeDistributedActorSystems.swift -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %target-run %t/a.out
+
+// RUN: %target-run %t/a.out PARAMETER_TYPE
+// RUN: %target-run %t/a.out RETURN_TYPE
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
@@ -17,7 +18,6 @@
 
 import Darwin
 import Distributed
-import FakeDistributedActorSystems
 import Foundation
 
 typealias DefaultDistributedActorSystem = FakeRoundtripActorSystem
@@ -1052,20 +1052,39 @@ struct BigGeneric<T>: Codable {
 }
 
 distributed actor D {
+  public distributed func getBigGeneric(_ value: BigGeneric<TypeXXXX>) {}
   public distributed func getBigGeneric() -> BigGeneric<TypeXXXX> {
-    return BigGeneric()
-  }
+     return BigGeneric()
+   }
 }
 
-func attempt(n: Int) {
-  var fname = "$s4dist1DC13getBigGenericAA0cD0VyAA8Type\(n)VGyF"
+func attempt(_ mode: Mode, n: Int) {
+  var funcName_returnType = "$s4dist1DC13getBigGenericAA0cD0VyAA8Type\(n)VGyF"
+  var funcName_param = "$s4dist1DC13getBigGenericyyAA0cD0VyAA8Type\(n)VGF"
 
   func tryLookup() {
-    let t = fname.withUTF8 {
-      __getReturnTypeInfo($0.baseAddress!, UInt($0.count), nil, nil)
-    }
+    let t: (any Any.Type)? =
+      switch mode {
+      case .returnType:
+        funcName_returnType.withUTF8 {
+          __getReturnTypeInfo($0.baseAddress!, UInt($0.count), nil, nil)
+        }
+
+      case .paramType:
+        funcName_param.withUTF8 { nameBuf in
+          var type: Any.Type?
+          withUnsafeMutablePointer(to: &type) { typePtr in
+            let ret = __getParameterTypeInfo(nameBuf.baseAddress!, UInt(nameBuf.count), nil, nil, typePtr._rawValue, 1)
+            if ret != 1 {
+              fatalError("Decoded \(ret) parameters, expected 1")
+            }
+          }
+          return type
+        }
+      }
+
     guard let t else {
-      print("couldn't look up type for: \(fname)")
+      print("couldn't look up type for mode: \(mode)")
       exit(1)
     }
     func examineType<T>(_t: T.Type) {
@@ -1081,10 +1100,23 @@ func attempt(n: Int) {
   }
 }
 
+enum Mode: String {
+  case returnType = "RETURN_TYPE"
+  case paramType = "PARAMETER_TYPE"
+}
+
 @main struct Main {
   static func main() {
+    if CommandLine.arguments.count < 2 {
+      fatalError("Expected explicit mode in command line arguments, was: \(CommandLine.arguments)")
+    }
+
+    let mode = Mode.init(rawValue: CommandLine.arguments.dropFirst().first!)!
+    print("Checking in mode: \(mode)...")
+
     for i in 1000...1999 {
-      attempt(n: i)
+      attempt(mode, n: i)
     }
+    print("Passed in mode: \(mode)!")
   }
-}
\ No newline at end of file
+}
diff --git a/test/Distributed/Runtime/distributed_actor_library_evolution_da_protocol_use.swift b/test/Distributed/Runtime/distributed_actor_library_evolution_da_protocol_use.swift
new file mode 100644
index 0000000000000..9a22c10107271
--- /dev/null
+++ b/test/Distributed/Runtime/distributed_actor_library_evolution_da_protocol_use.swift
@@ -0,0 +1,54 @@
+// REQUIRES: VENDOR=apple
+// REQUIRES: OS=macosx || OS=linux-gnu
+// REQUIRES: concurrency
+// REQUIRES: distributed
+// UNSUPPORTED: use_os_stdlib
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-build-swift -Xfrontend -validate-tbd-against-ir=all -enable-library-evolution -target %target-swift-5.9-abi-triple -parse-as-library -emit-library -emit-module-path %t/Library.swiftmodule -module-name Library %t/library.swift -o %t/%target-library-name(Library)
+// RUN: %target-build-swift -Xfrontend -validate-tbd-against-ir=all -target %target-swift-5.9-abi-triple -parse-as-library -lLibrary -module-name main -I %t -L %t %t/main.swift -o %t/a.out
+
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+//--- library.swift
+import Distributed
+
+public protocol SimpleProtocol: DistributedActor
+    where ActorSystem == LocalTestingDistributedActorSystem {
+
+  // nonisolated override var id: ID { get } // comes from DistributedActor
+
+  // Has to have a distributed method to fail
+  distributed func test() -> Int
+}
+
+//--- main.swift
+import Distributed
+import Library
+
+public distributed actor SimpleActor: SimpleProtocol {
+  public distributed func test() -> Int {
+    print("SimpleActor.test")
+    return 1
+  }
+}
+
+public func makeFromFail<Act: SimpleProtocol>(_ act: Act) async {
+  print(act.id)
+  try! await print("act.test() = \(act.test())")
+  // CHECK: SimpleActor.test
+  // CHECK: act.test() = 1
+}
+
+@main
+struct TestSwiftFrameworkTests {
+  static func main() async {
+    let system = LocalTestingDistributedActorSystem()
+
+    let simpleActor = SimpleActor(actorSystem: system)
+    await makeFromFail(simpleActor)
+  }
+}
\ No newline at end of file
diff --git a/test/Distributed/Runtime/distributed_actor_localSystem_distributedProtocol.swift b/test/Distributed/Runtime/distributed_actor_localSystem_distributedProtocol.swift
index 92bcc63ff5e88..28ad023e489ba 100644
--- a/test/Distributed/Runtime/distributed_actor_localSystem_distributedProtocol.swift
+++ b/test/Distributed/Runtime/distributed_actor_localSystem_distributedProtocol.swift
@@ -3,6 +3,11 @@
 // RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s --color
 
+// Run again with library evolution:
+// RUN: %target-build-swift -module-name main -j2 -parse-as-library -enable-library-evolution -I %t %s -plugin-path %swift-plugin-dir -o %t/evo.out
+// RUN: %target-codesign %t/evo.out
+// RUN: %target-run %t/evo.out | %FileCheck %s --color
+
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: distributed
@@ -14,9 +19,6 @@
 // rdar://90373022
 // UNSUPPORTED: OS=watchos
 
-// rdar://125628060
-// UNSUPPORTED: CPU=arm64e
- 
 import Distributed
 
 @Resolvable
diff --git a/test/Distributed/Runtime/distributed_actor_localSystem_distributedProtocol_variable.swift b/test/Distributed/Runtime/distributed_actor_localSystem_distributedProtocol_variable.swift
index 2ff3022daeccd..c10fd6cc5ebd4 100644
--- a/test/Distributed/Runtime/distributed_actor_localSystem_distributedProtocol_variable.swift
+++ b/test/Distributed/Runtime/distributed_actor_localSystem_distributedProtocol_variable.swift
@@ -3,6 +3,11 @@
 // RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s --color
 
+// Run again with library evolution:
+// RUN: %target-build-swift -module-name main -j2 -parse-as-library -enable-library-evolution -I %t %s -plugin-path %swift-plugin-dir -o %t/evo.out
+// RUN: %target-codesign %t/evo.out
+// RUN: %target-run %t/evo.out | %FileCheck %s --color
+
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: distributed
@@ -14,9 +19,6 @@
 // rdar://90373022
 // UNSUPPORTED: OS=watchos
 
-// rdar://125628060
-// UNSUPPORTED: CPU=arm64e
- 
 import Distributed
 
 @Resolvable
diff --git a/test/Distributed/Runtime/distributed_actor_localSystem_generic_system.swift b/test/Distributed/Runtime/distributed_actor_localSystem_generic_system.swift
index aedb6b830ee1f..54b2c3eada3cd 100644
--- a/test/Distributed/Runtime/distributed_actor_localSystem_generic_system.swift
+++ b/test/Distributed/Runtime/distributed_actor_localSystem_generic_system.swift
@@ -3,6 +3,11 @@
 // RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s --color
 
+// Run again with library evolution:
+// RUN: %target-build-swift -module-name main -j2 -parse-as-library -enable-library-evolution -I %t %s -plugin-path %swift-plugin-dir -o %t/evo.out
+// RUN: %target-codesign %t/evo.out
+// RUN: %target-run %t/evo.out | %FileCheck %s --color
+
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: distributed
diff --git a/test/Distributed/Runtime/distributed_actor_localSystem_manual_conformance.swift b/test/Distributed/Runtime/distributed_actor_localSystem_manual_conformance.swift
index 4dca582f45a6c..93f262a1938bc 100644
--- a/test/Distributed/Runtime/distributed_actor_localSystem_manual_conformance.swift
+++ b/test/Distributed/Runtime/distributed_actor_localSystem_manual_conformance.swift
@@ -3,6 +3,11 @@
 // RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s --color
 
+// Run again with library evolution:
+// RUN: %target-build-swift -module-name main -j2 -parse-as-library -enable-library-evolution -I %t %s -plugin-path %swift-plugin-dir -o %t/evo.out
+// RUN: %target-codesign %t/evo.out
+// RUN: %target-run %t/evo.out | %FileCheck %s --color
+
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: distributed
@@ -14,9 +19,6 @@
 // rdar://90373022
 // UNSUPPORTED: OS=watchos
 
-// rdar://125628060
-// UNSUPPORTED: CPU=arm64e
-
 import Distributed
 
 @available(SwiftStdlib 6.0, *)
diff --git a/test/Distributed/Runtime/distributed_actor_protocol_call_resilient_lib.swift b/test/Distributed/Runtime/distributed_actor_protocol_call_resilient_lib.swift
index 0e800d625732a..64e66a5485d9f 100644
--- a/test/Distributed/Runtime/distributed_actor_protocol_call_resilient_lib.swift
+++ b/test/Distributed/Runtime/distributed_actor_protocol_call_resilient_lib.swift
@@ -71,6 +71,7 @@
 // Locating the built libraries failed on Linux (construction of test case),
 // but we primarily care about macOS in this test
 // UNSUPPORTED: OS=linux-gnu
+// UNSUPPORTED: OS=freebsd
 
 // UNSUPPORTED: use_os_stdlib
 // UNSUPPORTED: back_deployment_runtime
diff --git a/test/Distributed/Runtime/distributed_actor_remoteCall_accessibleFunctions.swift b/test/Distributed/Runtime/distributed_actor_remoteCall_accessibleFunctions.swift
new file mode 100644
index 0000000000000..6cf456e9851e0
--- /dev/null
+++ b/test/Distributed/Runtime/distributed_actor_remoteCall_accessibleFunctions.swift
@@ -0,0 +1,84 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-6.0-abi-triple %S/../Inputs/FakeDistributedActorSystems.swift -plugin-path %swift-plugin-dir
+// RUN: %target-build-swift -module-name ActorsFramework -target %target-swift-6.0-abi-triple -j2 -parse-as-library -I %t %s %S/../Inputs/FakeDistributedActorSystems.swift -plugin-path %swift-plugin-dir -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: env %env-SWIFT_DUMP_ACCESSIBLE_FUNCTIONS=true %target-run %t/a.out 2>&1 | %FileCheck %s --color --dump-input=always
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+// rdar://76038845
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+// FIXME(distributed): Distributed actors currently have some issues on windows, isRemote always returns false. rdar://82593574
+// UNSUPPORTED: OS=windows-msvc
+
+import Distributed
+import FakeDistributedActorSystems
+
+// ==== Known actor system -----------------------------------------------------
+
+public struct Response: Codable, Sendable {
+  let resp: Int
+  public init(resp: Int) {
+    self.resp = resp
+  }
+}
+
+public struct Provider: Codable, Sendable {
+  let r1: Int
+  public init(r1: Int) {
+    self.r1 = r1
+  }
+}
+
+@Resolvable
+public protocol DistributedNotificationService: DistributedActor
+where ActorSystem == FakeRoundtripActorSystem {
+  distributed func getArray(a1: [Int], a2: String?) async throws -> [Response]
+}
+
+distributed actor DistributedNotificationServiceImpl: DistributedNotificationService {
+  typealias ActorSystem = FakeRoundtripActorSystem
+
+  distributed func getArray(a1: [Int], a2: String?) async throws -> [Response] {
+    []  // mock impl is enough
+  }
+}
+
+// ==== ------------------------------------------------------------------------
+
+@main struct Main {
+  static func main() async throws {
+    let roundtripSystem = FakeRoundtripActorSystem()
+
+    let real: any DistributedNotificationService = DistributedNotificationServiceImpl(
+      actorSystem: roundtripSystem)
+
+    let proxy: any DistributedNotificationService =
+      try $DistributedNotificationService.resolve(id: real.id, using: roundtripSystem)
+    _ = try await proxy.getArray(a1: [], a2: "")
+
+    // CHECK: ==== Accessible Function Records ====
+
+    // CHECK: Record name: $s15ActorsFramework30DistributedNotificationServicePAA0C001_C9ActorStubRzrlE8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtYaKFTE
+    // CHECK:  Demangled: distributed thunk (extension in ActorsFramework):ActorsFramework.DistributedNotificationService< where A: Distributed._DistributedActorStub>.getArray(a1: Swift.Array<Swift.Int>, a2: Swift.Optional<Swift.String>) async throws -> Swift.Array<ActorsFramework.Response>
+    // CHECK:  Function Ptr: [[PTR:0x.*]]
+    // CHECK:  Flags.IsDistributed: 1
+
+    // CHECK: Record name: $s15ActorsFramework34DistributedNotificationServiceImplC8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtYaKFTE
+    // CHECK:  Demangled: distributed thunk ActorsFramework.DistributedNotificationServiceImpl.getArray(a1: Swift.Array<Swift.Int>, a2: Swift.Optional<Swift.String>) async throws -> Swift.Array<ActorsFramework.Response>
+    // CHECK:  Function Ptr: [[PTR:0x.*]]
+    // CHECK:  Flags.IsDistributed: 1
+
+    // CHECK: Record name: $s15ActorsFramework31$DistributedNotificationServiceC8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtYaKFTE
+    // CHECK:  Demangled: distributed thunk ActorsFramework.$DistributedNotificationService.getArray(a1: Swift.Array<Swift.Int>, a2: Swift.Optional<Swift.String>) async throws -> Swift.Array<ActorsFramework.Response>
+    // CHECK:  Function Ptr: [[PTR:0x.*]]
+    // CHECK:  Flags.IsDistributed: 1
+
+    // CHECK: Record count: 3
+    // CHECK: ==== End of Accessible Function Records ====
+  }
+}
diff --git a/test/Distributed/Runtime/distributed_actor_remoteCall_accessibleFunctions_crossModule.swift b/test/Distributed/Runtime/distributed_actor_remoteCall_accessibleFunctions_crossModule.swift
new file mode 100644
index 0000000000000..6c4273f05bff4
--- /dev/null
+++ b/test/Distributed/Runtime/distributed_actor_remoteCall_accessibleFunctions_crossModule.swift
@@ -0,0 +1,175 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+/// Build the fake actor systems lib
+// RUN: %target-build-swift                                                    \
+// RUN:     -target %target-swift-6.0-abi-triple                               \
+// RUN:     -parse-as-library -emit-library                                    \
+// RUN:     -emit-module-path %t/FakeDistributedActorSystems.swiftmodule       \
+// RUN:     -module-name FakeDistributedActorSystems                           \
+// RUN:     -plugin-path %swift-plugin-dir                                     \
+// RUN:      %S/../Inputs/FakeDistributedActorSystems.swift                    \
+// RUN:     -enable-library-evolution                                          \
+// RUN:     -Xfrontend -validate-tbd-against-ir=all                            \
+// RUN:     -o %t/%target-library-name(FakeDistributedActorSystems)
+
+/// Build the ResilientAPILib
+// RUN: %target-build-swift                                                    \
+// RUN:     -target %target-swift-6.0-abi-triple                               \
+// RUN:     -parse-as-library -emit-library                                    \
+// RUN:     -emit-module-path %t/ResilientAPILib.swiftmodule                   \
+// RUN:     -module-name ResilientAPILib                                       \
+// RUN:     -I %t                                                              \
+// RUN:     -L %t                                                              \
+// RUN:     -plugin-path %swift-plugin-dir                                     \
+// RUN:     %t/src/ResilientAPILib.swift                                       \
+// RUN:     -lFakeDistributedActorSystems                                      \
+// RUN:     -enable-library-evolution                                          \
+// RUN:     -Xfrontend -validate-tbd-against-ir=all                            \
+// RUN:     -o %t/%target-library-name(ResilientAPILib)
+
+/// Build the ResilientImplLib
+// RUN: %target-build-swift                                                    \
+// RUN:     -target %target-swift-6.0-abi-triple                               \
+// RUN:     -parse-as-library -emit-library                                    \
+// RUN:     -emit-module-path %t/ResilientImplLib.swiftmodule                  \
+// RUN:     -module-name ResilientImplLib                                      \
+// RUN:     -I %t                                                              \
+// RUN:     -L %t                                                              \
+// RUN:     -plugin-path %swift-plugin-dir                                     \
+// RUN:     %t/src/ResilientImplLib.swift                                      \
+// RUN:     -lFakeDistributedActorSystems                                      \
+// RUN:     -lResilientAPILib                                                  \
+// RUN:     -enable-library-evolution                                          \
+// RUN:     -Xfrontend -validate-tbd-against-ir=all                            \
+// RUN:     -o %t/%target-library-name(ResilientImplLib)
+
+/// Build the client
+// RUN: %target-build-swift                                                    \
+// RUN:     -target %target-swift-6.0-abi-triple                               \
+// RUN:     -parse-as-library                                                  \
+// RUN:     -lFakeDistributedActorSystems                                      \
+// RUN:     -lResilientAPILib                                                  \
+// RUN:     -lResilientImplLib                                                 \
+// RUN:     -module-name main                                                  \
+// RUN:     -I %t                                                              \
+// RUN:     -L %t                                                              \
+// RUN:     -plugin-path %swift-plugin-dir                                     \
+// RUN:     %s                                                                 \
+// RUN:     -enable-library-evolution                                          \
+// RUN:     -Xfrontend -validate-tbd-against-ir=all                            \
+// RUN:     -o %t/a.out
+
+// Sign the main binary and all libraries
+// RUN: %target-codesign %t/a.out
+// RUN: %target-codesign %t/%target-library-name(FakeDistributedActorSystems)
+// RUN: %target-codesign %t/%target-library-name(ResilientAPILib)
+// RUN: %target-codesign %t/%target-library-name(ResilientImplLib)
+
+// Run and verify output
+// RUN: env %env-SWIFT_DUMP_ACCESSIBLE_FUNCTIONS=true %target-run %t/a.out                                                   \
+// RUN:     %t/%target-library-name(FakeDistributedActorSystems)               \
+// RUN:     %t/%target-library-name(ResilientAPILib)                           \
+// RUN:     %t/%target-library-name(ResilientImplLib)                          \
+// RUN:     2>&1                                                               \
+// RUN:     | %FileCheck %s --color --dump-input=always
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+// Locating the built libraries failed on Linux (construction of test case),
+// but we primarily care about macOS in this test
+// UNSUPPORTED: OS=linux-gnu || OS=freebsd
+
+// %env does not seem to work on Windows
+// UNSUPPORTED: OS=windows-msvc
+
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: remote_run || device_run
+
+//--- ResilientAPILib.swift
+
+import Distributed
+import FakeDistributedActorSystems
+
+@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+public struct Response: Codable {}
+
+@Resolvable
+@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+public protocol ServiceProtocol: DistributedActor where ActorSystem == FakeRoundtripActorSystem {
+  distributed func getArray(a1: [Int], a2: String?) -> [Response]
+}
+
+//--- ResilientImplLib.swift
+
+import ResilientAPILib
+
+import Distributed
+import FakeDistributedActorSystems
+
+@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+public distributed actor ServiceImpl: ServiceProtocol {
+  public typealias ActorSystem = FakeRoundtripActorSystem
+
+  public distributed func getArray(a1: [Int], a2: String?) -> [Response] {
+    []
+  }
+}
+
+//--- Main.swift
+
+import ResilientAPILib
+import ResilientImplLib
+
+import Distributed
+import FakeDistributedActorSystems
+
+@main
+struct Main {
+  static func main() async throws {
+    if #available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *) {
+      let system = FakeRoundtripActorSystem()
+
+      let real: any ServiceProtocol = ServiceImpl(actorSystem: system)
+
+      let proxy: any ServiceProtocol =
+        try $ServiceProtocol.resolve(id: real.id, using: system)
+
+      // just in order to see if we crash and trigger the accessible funcs printout
+      _ = try await proxy.getArray(a1: [], a2: "")
+
+      // === We expect records for accessible functions from other modules as well,
+      // and especially we want to see records for the `$` macro generated stubs,
+      // including
+
+      // CHECK: ==== Accessible Function Records ====
+      // CHECK: Record name: $s16ResilientImplLib07ServiceB0C8getArray2a12a2Say0A6APILib8ResponseVGSaySiG_SSSgtYaKFTE
+      // CHECK: Demangled: distributed thunk ResilientImplLib.ServiceImpl.getArray(a1: Swift.Array<Swift.Int>, a2: Swift.Optional<Swift.String>) async throws -> Swift.Array<ResilientAPILib.Response>
+
+      // CHECK: Record name: $s15ResilientAPILib15ServiceProtocolPAA11Distributed01_E9ActorStubRzrlE8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtYaKFTE
+      // CHECK: Demangled: distributed thunk (extension in ResilientAPILib):ResilientAPILib.ServiceProtocol< where A: Distributed._DistributedActorStub>.getArray(a1: Swift.Array<Swift.Int>, a2: Swift.Optional<Swift.String>) async throws -> Swift.Array<ResilientAPILib.Response>
+
+      // CHECK: Record name: $s15ResilientAPILib16$ServiceProtocolC8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtYaKFTE
+      // CHECK: Demangled: distributed thunk ResilientAPILib.$ServiceProtocol.getArray(a1: Swift.Array<Swift.Int>, a2: Swift.Optional<Swift.String>) async throws -> Swift.Array<ResilientAPILib.Response>
+
+      // CHECK: Record name: $s4main15ServiceProtocolPAA11Distributed01_D9ActorStubRzrlE8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtYaKFTE
+      // CHECK: Demangled: distributed thunk (extension in main):main.ServiceProtocol< where A: Distributed._DistributedActorStub>.getArray(a1: Swift.Array<Swift.Int>, a2: Swift.Optional<Swift.String>) async throws -> Swift.Array<main.Response>
+
+      // CHECK: Record name: $s4main11ServiceImplC8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtYaKFTE
+      // CHECK: Demangled: distributed thunk main.ServiceImpl.getArray(a1: Swift.Array<Swift.Int>, a2: Swift.Optional<Swift.String>) async throws -> Swift.Array<main.Response>
+
+      // CHECK: Record name: $s4main16$ServiceProtocolC8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtYaKFTE
+      // CHECK: Demangled: distributed thunk main.$ServiceProtocol.getArray(a1: Swift.Array<Swift.Int>, a2: Swift.Optional<Swift.String>) async throws -> Swift.Array<main.Response>
+
+      // We expect these to be the exact records we get, no other ones:
+      // CHECK: Record count: 6
+      
+      // CHECK: ==== End of Accessible Function Records ====
+
+      print("DONE") // CHECK: DONE
+    }
+  }
+}
diff --git a/test/Distributed/Runtime/distributed_actor_remoteCall_accessibleFunctions_crossModule_irgen.swift b/test/Distributed/Runtime/distributed_actor_remoteCall_accessibleFunctions_crossModule_irgen.swift
new file mode 100644
index 0000000000000..2df7839292d52
--- /dev/null
+++ b/test/Distributed/Runtime/distributed_actor_remoteCall_accessibleFunctions_crossModule_irgen.swift
@@ -0,0 +1,249 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+/// Build the fake actor systems lib
+// RUN: %target-build-swift                                                    \
+// RUN:     -target %target-swift-6.0-abi-triple                               \
+// RUN:     -parse-as-library -emit-library                                    \
+// RUN:     -emit-module-path %t/FakeDistributedActorSystems.swiftmodule       \
+// RUN:     -module-name FakeDistributedActorSystems                           \
+// RUN:     -plugin-path %swift-plugin-dir                                     \
+// RUN:      %S/../Inputs/FakeDistributedActorSystems.swift                    \
+// RUN:     -enable-library-evolution                                          \
+// RUN:     -Xfrontend -validate-tbd-against-ir=all                            \
+// RUN:     -o %t/%target-library-name(FakeDistributedActorSystems)
+
+/// Build the ResilientAPILib
+// RUN: %target-build-swift                                                    \
+// RUN:     -target %target-swift-6.0-abi-triple                               \
+// RUN:     -parse-as-library -emit-library                                    \
+// RUN:     -emit-module-path %t/ResilientAPILib.swiftmodule                   \
+// RUN:     -module-name ResilientAPILib                                       \
+// RUN:     -I %t                                                              \
+// RUN:     -L %t                                                              \
+// RUN:     -plugin-path %swift-plugin-dir                                     \
+// RUN:     %t/src/ResilientAPILib.swift                                       \
+// RUN:     %t/src/ResilientAPILibFile2.swift                                  \
+// RUN:     -lFakeDistributedActorSystems                                      \
+// RUN:     -enable-library-evolution                                          \
+// RUN:     -Xfrontend -validate-tbd-against-ir=all                            \
+// RUN:     -o %t/%target-library-name(ResilientAPILib)
+
+/// Build the ResilientImplLib
+// RUN: %target-build-swift                                                    \
+// RUN:     -target %target-swift-6.0-abi-triple                               \
+// RUN:     -parse-as-library -emit-library                                    \
+// RUN:     -module-name ResilientImplLib                                      \
+// RUN:     -I %t                                                              \
+// RUN:     -L %t                                                              \
+// RUN:     -plugin-path %swift-plugin-dir                                     \
+// RUN:     %t/src/ResilientImplLib.swift                                      \
+// RUN:     -lFakeDistributedActorSystems                                      \
+// RUN:     -lResilientAPILib                                                  \
+// RUN:     -enable-library-evolution                                          \
+// RUN:     -Xfrontend -validate-tbd-against-ir=all                            \
+// RUN:     -emit-irgen                                                        \
+// RUN:     | %FileCheck %s --color --dump-input=always
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+// Locating the built libraries failed on Linux (construction of test case),
+// but we primarily care about macOS in this test
+// UNSUPPORTED: OS=linux-gnu || OS=freebsd
+
+// %env does not seem to work on Windows
+// UNSUPPORTED: OS=windows-msvc
+
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: remote_run || device_run
+// UNSUPPORTED: OS=watchos
+
+//--- ResilientAPILib.swift
+
+import Distributed
+import FakeDistributedActorSystems
+
+@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+public struct Response: Codable {}
+
+@Resolvable
+@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+public protocol DistributedNotificationService: DistributedActor where ActorSystem == FakeRoundtripActorSystem {
+  distributed func getArray(a1: [Int], a2: String?) -> [Response]
+}
+
+public protocol IdentifiableActor {
+    static var actorID: FakeRoundtripActorSystem.ActorID { get }
+}
+
+//--- ResilientAPILibFile2.swift
+
+final class Another { }
+
+//--- ResilientImplLib.swift
+
+import ResilientAPILib
+
+import Distributed
+import FakeDistributedActorSystems
+
+@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+public distributed actor ServiceImpl: DistributedNotificationService, IdentifiableActor {
+  public typealias ActorSystem = FakeRoundtripActorSystem
+
+  public static var actorID: FakeRoundtripActorSystem.ActorID {
+    .init(parse: "test")
+  }
+
+  public distributed func getArray(a1: [Int], a2: String?) -> [Response] {
+    []
+  }
+}
+
+extension ServiceImpl {}
+
+//--- ResilientImplLibFile2.swift
+
+class AnotherImpl {}
+
+
+//        @"protocol conformance descriptor for ResilientImplLib.ServiceImpl : ResilientAPILib.DistributedNotificationService in ResilientImplLib" = constant {
+// CHECK: @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc" = constant {
+// CHECK-SAME:   i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32, i32
+// CHECK-SAME: } {
+// CHECK-SAME:   i32 add (
+// CHECK-SAME:     i32 trunc (
+// CHECK-SAME:       i64 sub (
+//                     i64 ptrtoint (ptr @"got.protocol descriptor for ResilientAPILib.DistributedNotificationService" to i64),
+// CHECK-SAME:         i64 ptrtoint (ptr @"got.$s15ResilientAPILib30DistributedNotificationServiceMp" to i64),
+//                     i64 ptrtoint (ptr @"protocol conformance descriptor for ResilientImplLib.ServiceImpl : ResilientAPILib.DistributedNotificationService in ResilientImplLib" to i64)
+// CHECK-SAME:         i64 ptrtoint (ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc" to i64)
+// CHECK-SAME:       ) to i32
+// CHECK-SAME:     ),
+// CHECK-SAME:     i32 1
+// CHECK-SAME:   ),
+//
+// CHECK-SAME:   i32 trunc (
+// CHECK-SAME:     i64 sub (
+//                   i64 ptrtoint (ptr @"nominal type descriptor for ResilientImplLib.ServiceImpl" to i64),
+// CHECK-SAME:       i64 ptrtoint (ptr @"$s16ResilientImplLib07ServiceB0CMn" to i64),
+// CHECK-SAME:       i64 ptrtoint (ptr getelementptr inbounds (
+// CHECK-SAME:         { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32, i32 },
+// CHECK-SAME:         ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc",
+// CHECK-SAME:         i32 0, i32 1
+// CHECK-SAME:       ) to i64)
+// CHECK-SAME:     ) to i32
+// CHECK-SAME:   ),
+//
+// CHECK-SAME:   i32 0,
+// CHECK-SAME:   i32 196608,
+// CHECK-SAME:   i32 3,
+//
+// CHECK-SAME:   i32 add (
+// CHECK-SAME:     i32 trunc (
+// CHECK-SAME:       i64 sub (
+//                     i64 ptrtoint (ptr @"got.base conformance descriptor for ResilientAPILib.DistributedNotificationService: Distributed.DistributedActor" to i64),
+// CHECK-SAME:         i64 ptrtoint (ptr @"got.$s15ResilientAPILib30DistributedNotificationServiceP0C00C5ActorTb" to i64),
+// CHECK-SAME:         i64 ptrtoint (ptr getelementptr inbounds (
+// CHECK-SAME:           { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32, i32 },
+// CHECK-SAME:           ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc",
+// CHECK-SAME:           i32 0, i32 5
+// CHECK-SAME:         ) to i64)
+// CHECK-SAME:       ) to i32
+// CHECK-SAME:     ),
+// CHECK-SAME:     i32 1
+// CHECK-SAME:   ),
+//
+// CHECK-SAME:   i32 trunc (
+// CHECK-SAME:     i64 sub (
+// CHECK-SAME:       i64 ptrtoint (ptr getelementptr (
+// CHECK-SAME:         i8, ptr @"associated conformance 16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AA0F00F5Actor",
+// CHECK-SAME:         i64 1
+// CHECK-SAME:       ) to i64),
+// CHECK-SAME:       i64 ptrtoint (ptr getelementptr inbounds (
+// CHECK-SAME:         { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32, i32 },
+// CHECK-SAME:         ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc",
+// CHECK-SAME:         i32 0, i32 6
+// CHECK-SAME:       ) to i64)
+// CHECK-SAME:     ) to i32
+// CHECK-SAME:   ),
+//
+// CHECK-SAME:   i32 add (
+// CHECK-SAME:     i32 trunc (
+// CHECK-SAME:       i64 sub (
+//                     i64 ptrtoint (ptr @"got.method descriptor for ResilientAPILib.DistributedNotificationService.getArray(a1: [Swift.Int], a2: Swift.String?) -> [ResilientAPILib.Response]" to i64),
+// CHECK-SAME:         i64 ptrtoint (ptr @"got.$s15ResilientAPILib30DistributedNotificationServiceP8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtFTq" to i64),
+// CHECK-SAME:         i64 ptrtoint (ptr getelementptr inbounds (
+// CHECK-SAME:           { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32, i32 },
+// CHECK-SAME:           ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc",
+// CHECK-SAME:           i32 0, i32 7
+// CHECK-SAME:         ) to i64)
+// CHECK-SAME:       ) to i32
+// CHECK-SAME:     ),
+// CHECK-SAME:     i32 1
+// CHECK-SAME:   ),
+//
+// CHECK-SAME:   i32 trunc (
+// CHECK-SAME:     i64 sub (
+//                   i64 ptrtoint (ptr @"protocol witness for ResilientAPILib.DistributedNotificationService.getArray(a1: [Swift.Int], a2: Swift.String?) -> [ResilientAPILib.Response] in conformance ResilientImplLib.ServiceImpl : ResilientAPILib.DistributedNotificationService in ResilientImplLib" to i64),
+// CHECK-SAME:       i64 ptrtoint (ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AadEP8getArray2a12a2SayAD8ResponseVGSaySiG_SSSgtFTW" to i64),
+// CHECK-SAME:       i64 ptrtoint (ptr getelementptr inbounds (
+// CHECK-SAME:         { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32, i32 },
+//                     ptr @"protocol conformance descriptor for ResilientImplLib.ServiceImpl : ResilientAPILib.DistributedNotificationService in ResilientImplLib",
+// CHECK-SAME:         ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc",
+// CHECK-SAME:         i32 0, i32 8
+// CHECK-SAME:       ) to i64)
+// CHECK-SAME:     ) to i32
+// CHECK-SAME:   ),
+//
+// THIS ONE HAS .7 IN OUR REAL EXAMPLE >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+// CHECK-SAME:   i32 add (
+// CHECK-SAME:     i32 trunc (
+// CHECK-SAME:       i64 sub (
+//                     i64 ptrtoint (ptr @"got.method descriptor for ResilientAPILib.DistributedNotificationService.getArray(a1: [Swift.Int], a2: Swift.String?) async throws -> [ResilientAPILib.Response]" to i64),
+// CHECK-SAME:         i64 ptrtoint (ptr @"got.$s15ResilientAPILib30DistributedNotificationServiceP8getArray2a12a2SayAA8ResponseVGSaySiG_SSSgtYaKFTqTE" to i64),
+// CHECK-SAME:         i64 ptrtoint (ptr getelementptr inbounds (
+// CHECK-SAME:           { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32, i32 },
+//                       ptr @"protocol conformance descriptor for ResilientImplLib.ServiceImpl : ResilientAPILib.DistributedNotificationService in ResilientImplLib",
+// CHECK-SAME:           ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc",
+// CHECK-SAME:           i32 0, i32 9
+// CHECK-SAME:         ) to i64)
+// CHECK-SAME:       ) to i32
+// CHECK-SAME:     ),
+// CHECK-SAME:     i32 1
+// CHECK-SAME:   ),
+// <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+//
+// CHECK-SAME:   i32 trunc (
+// CHECK-SAME:     i64 sub (
+//                   i64 ptrtoint (ptr @"async function pointer to distributed thunk protocol witness for ResilientAPILib.DistributedNotificationService.getArray(a1: [Swift.Int], a2: Swift.String?) async throws -> [ResilientAPILib.Response] in conformance ResilientImplLib.ServiceImpl : ResilientAPILib.DistributedNotificationService in ResilientImplLib" to i64),
+// CHECK-SAME:       i64 ptrtoint (ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AadEP8getArray2a12a2SayAD8ResponseVGSaySiG_SSSgtYaKFTWTETu" to i64),
+// CHECK-SAME:       i64 ptrtoint (ptr getelementptr inbounds (
+// CHECK-SAME:         { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32, i32 },
+//                     ptr @"protocol conformance descriptor for ResilientImplLib.ServiceImpl : ResilientAPILib.DistributedNotificationService in ResilientImplLib",
+// CHECK-SAME:         ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc",
+// CHECK-SAME:         i32 0, i32 10
+// CHECK-SAME:       ) to i64)
+// CHECK-SAME:     ) to i32
+// CHECK-SAME:   ),
+//
+// CHECK-SAME:   i16 0,
+// CHECK-SAME:   i16 1,
+// CHECK-SAME:   i32 0,
+//
+// CHECK-SAME:   i32 trunc (
+// CHECK-SAME:     i64 sub (
+//                   i64 ptrtoint (ptr @"metadata instantiation cache for protocol conformance descriptor for ResilientImplLib.ServiceImpl : ResilientAPILib.DistributedNotificationService in ResilientImplLib" to i64),
+// CHECK-SAME:       i64 ptrtoint (ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMcMK" to i64),
+// CHECK-SAME:       i64 ptrtoint (ptr getelementptr inbounds (
+// CHECK-SAME:         { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32, i32 },
+//                     ptr @"protocol conformance descriptor for ResilientImplLib.ServiceImpl : ResilientAPILib.DistributedNotificationService in ResilientImplLib",
+// CHECK-SAME:         ptr @"$s16ResilientImplLib07ServiceB0C0A6APILib023DistributedNotificationD0AAMc",
+// CHECK-SAME:         i32 0, i32 14
+// CHECK-SAME:       ) to i64)
+// CHECK-SAME:     ) to i32
+// CHECK-SAME:   )
+// CHECK-SAME: }, section "__TEXT,__const", no_sanitize_address, align 4
diff --git a/test/Distributed/Runtime/distributed_actor_remoteCall_roundtrip.swift b/test/Distributed/Runtime/distributed_actor_remoteCall_roundtrip.swift
index a653101191543..205c7160ffd30 100644
--- a/test/Distributed/Runtime/distributed_actor_remoteCall_roundtrip.swift
+++ b/test/Distributed/Runtime/distributed_actor_remoteCall_roundtrip.swift
@@ -4,8 +4,6 @@
 // RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s --enable-var-scope
 
-// X: %target-run-simple-swift( -Xfrontend -module-name=main -target %target-swift-5.7-abi-triple  -parse-as-library -Xfrontend -I -Xfrontend %t ) | %FileCheck %s
-
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: distributed
diff --git a/test/Distributed/Runtime/distributed_actor_remoteCall_roundtrip_nonisolated_nonsending_by_default.swift b/test/Distributed/Runtime/distributed_actor_remoteCall_roundtrip_nonisolated_nonsending_by_default.swift
new file mode 100644
index 0000000000000..5842c63d62368
--- /dev/null
+++ b/test/Distributed/Runtime/distributed_actor_remoteCall_roundtrip_nonisolated_nonsending_by_default.swift
@@ -0,0 +1,87 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule \
+// RUN:     -module-name FakeDistributedActorSystems -target %target-swift-5.7-abi-triple \
+// RUN:     %S/../Inputs/FakeDistributedActorSystems.swift
+
+// RUN: %target-build-swift -module-name main -enable-upcoming-feature NonisolatedNonsendingByDefault \
+// RUN:     -target %target-swift-5.7-abi-triple -j2 -parse-as-library -I %t %s \
+// RUN:     %S/../Inputs/FakeDistributedActorSystems.swift -o %t/a.out
+
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s --enable-var-scope
+
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+// rdar://76038845
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+// FIXME(distributed): Distributed actors currently have some issues on windows, isRemote always returns false. rdar://82593574
+// UNSUPPORTED: OS=windows-msvc
+
+import Distributed
+import FakeDistributedActorSystems
+
+typealias DefaultDistributedActorSystem = FakeRoundtripActorSystem
+
+distributed actor Greeter: CustomStringConvertible {
+  distributed func echo(name: String) -> String {
+    return "Echo: \(name) (impl on: \(self.id))"
+  }
+
+  nonisolated var description: String {
+    "\(Self.self)(\(id))"
+  }
+}
+
+extension Greeter {
+  distributed func echoInExtension(name: String) -> String {
+    return "Echo: \(name) (impl on: \(self.id))"
+  }
+}
+
+nonisolated extension Greeter {
+  distributed func echoInNonisolatedExtension(name: String) -> String {
+    return "Echo: \(name) (impl on: \(self.id))"
+  }
+}
+
+struct SomeError: Error {}
+
+// ==== Test -------------------------------------------------------------------
+
+func test() async throws {
+  let system = DefaultDistributedActorSystem()
+
+  let local = Greeter(actorSystem: system)
+  let ref = try Greeter.resolve(id: local.id, using: system)
+
+  let reply = try await ref.echo(name: "Caplin")
+  // CHECK: > encode argument name:name, value: Caplin
+  // CHECK-NOT: > encode error type
+  // CHECK: > encode return type: Swift.String
+  // CHECK: > done recording
+  // CHECK: >> remoteCall
+  // CHECK: > decode return type: Swift.String
+  // CHECK: > decode argument: Caplin
+  // CHECK: << onReturn: Echo: Caplin (impl on: ActorAddress(address: "<unique-id>"))
+
+  print("got: \(reply)")
+  // CHECK: got: Echo: Caplin (impl on: ActorAddress(address: "<unique-id>"))
+
+  // just double check there's no surprises with distributed thunks in extensions
+  _ = try await ref.echoInExtension(name: "Bob")
+  _ = try await ref.echoInNonisolatedExtension(name: "Alice")
+
+  print("OK") // CHECK: OK
+}
+
+@main struct Main {
+  static func main() async {
+    try! await test()
+  }
+}
diff --git a/test/Distributed/actor_protocols.swift b/test/Distributed/actor_protocols.swift
index d3e728ff5de16..197e9ec53c514 100644
--- a/test/Distributed/actor_protocols.swift
+++ b/test/Distributed/actor_protocols.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-5.7-abi-triple %S/Inputs/FakeDistributedActorSystems.swift
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
 // REQUIRES: concurrency
 // REQUIRES: distributed
 
@@ -95,7 +95,7 @@ actor A3: AnyActor {} // expected-warning {{'AnyActor' is deprecated: Use 'any A
 distributed actor DA3: AnyActor {} // expected-warning {{'AnyActor' is deprecated: Use 'any Actor' with 'DistributedActor.asLocalActor' instead}}
 
 class C3: AnyActor { // expected-warning {{'AnyActor' is deprecated: Use 'any Actor' with 'DistributedActor.asLocalActor' instead}}
-  // expected-warning@-1 {{non-final class 'C3' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+  // expected-warning@-1 {{non-final class 'C3' cannot conform to the 'Sendable' protocol}}
 }
 
 struct S3: AnyActor { // expected-warning {{'AnyActor' is deprecated: Use 'any Actor' with 'DistributedActor.asLocalActor' instead}}
diff --git a/test/Distributed/distributed_actor_accessor_thunks_32bit.swift b/test/Distributed/distributed_actor_accessor_thunks_32bit.swift
index 53e4588a6fdd5..0b6a0f6ab5b85 100644
--- a/test/Distributed/distributed_actor_accessor_thunks_32bit.swift
+++ b/test/Distributed/distributed_actor_accessor_thunks_32bit.swift
@@ -94,7 +94,7 @@ public distributed actor MyOtherActor {
 
 // CHECK: define hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTE"
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTETF"(%swift.context* swiftasync %0, %swift.opaque* nocapture %1, i8* %2, i8* %3, {{.*}}, %T27distributed_actor_accessors7MyActorC* [[ACTOR:%.*]], %swift.type* [[DECODER_TYPE:%.*]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTETF"(%swift.context* swiftasync %0, %swift.opaque* {{(nocapture|captures\(none\))}} %1, i8* %2, i8* %3, {{.*}}, %T27distributed_actor_accessors7MyActorC* [[ACTOR:%.*]], %swift.type* [[DECODER_TYPE:%.*]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 /// Read the current offset and cast an element to `Int`
 
@@ -119,7 +119,7 @@ public distributed actor MyOtherActor {
 // CHECK: missing-witness1:
 // CHECK-NEXT: call void @llvm.trap()
 // CHECK-NEXT: unreachable
-// CHECK: call swiftcc void @"$s27FakeDistributedActorSystems0A17InvocationDecoderC18decodeNextArgumentxyKSeRzSERzlF"(%swift.opaque* noalias nocapture sret(%swift.opaque) [[ARG_0_RES_SLOT]], %swift.type* %arg_type, i8** [[ENCODABLE_WITNESS]], i8** [[DECODABLE_WITNESS]], %T27FakeDistributedActorSystems0A17InvocationDecoderC* swiftself [[DECODER]], %swift.error** noalias nocapture dereferenceable(4) %swifterror)
+// CHECK: call swiftcc void @"$s27FakeDistributedActorSystems0A17InvocationDecoderC18decodeNextArgumentxyKSeRzSERzlF"(%swift.opaque* noalias{{( nocapture)?}} sret(%swift.opaque){{( captures\(none\))?}} [[ARG_0_RES_SLOT]], %swift.type* %arg_type, i8** [[ENCODABLE_WITNESS]], i8** [[DECODABLE_WITNESS]], %T27FakeDistributedActorSystems0A17InvocationDecoderC* swiftself [[DECODER]], %swift.error** noalias {{(nocapture|captures\(none\))}} dereferenceable(4) %swifterror)
 
 // CHECK: store %swift.error* null, %swift.error** %swifterror
 // CHECK-NEXT: [[ARG_0_VAL_ADDR:%.*]] = bitcast i8* [[ARG_0_VALUE_BUF]] to %TSi*
@@ -145,7 +145,8 @@ public distributed actor MyOtherActor {
 // CHECK-SAME: %T27distributed_actor_accessors7MyActorC* [[ACTOR]])
 
 // CHECK-NEXT: [[TASK_REF:%.*]] = extractvalue { i8*, %swift.error* } [[THUNK_RESULT]], 0
-// CHECK-NEXT: {{.*}} = call i8* @__swift_async_resume_project_context(i8* [[TASK_REF]])
+// CHECK-NEXT: [[CALLER_ASYNC_CTXT:%.*]] = load ptr, ptr [[TASK_REF]]
+// CHECK-NEXT:  store ptr [[CALLER_ASYNC_CTXT]], ptr
 // CHECK: {{.*}} = call i1 (i8*, i1, ...) @llvm.coro.end.async({{.*}}, %swift.context* {{.*}}, %swift.error* {{.*}})
 
 /// ---> Thunk and distributed method accessor for `simple2`
@@ -178,7 +179,8 @@ public distributed actor MyOtherActor {
 // CHECK-SAME: %T27distributed_actor_accessors7MyActorC* [[ACTOR]])
 
 // CHECK-NEXT: [[TASK_REF:%.*]] = extractvalue { i8*, i32, i32, i32, %swift.error* } [[THUNK_RESULT]], 0
-// CHECK-NEXT: {{.*}} = call i8* @__swift_async_resume_project_context(i8* [[TASK_REF]])
+// CHECK-NEXT: [[CALLER_ASYNC_CTXT:%.*]] = load ptr, ptr [[TASK_REF]]
+// CHECK-NEXT:  store ptr [[CALLER_ASYNC_CTXT]], ptr
 
 /// Initialize the result buffer with values produced by the thunk
 
@@ -194,7 +196,7 @@ public distributed actor MyOtherActor {
 // CHECK: define hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple3ySiSSYaKFTE"
 
 /// !!! in `simple3` interesting bits are: argument value extraction (because string is exploded into N arguments) and call to distributed thunk
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple3ySiSSYaKFTETF"(%swift.context* swiftasync %0, %swift.opaque* nocapture [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUFF:%.*]], i8* [[SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors7MyActorC* [[ACTOR]], %swift.type* [[DECODER_TYPE:%.*]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple3ySiSSYaKFTETF"(%swift.context* swiftasync %0, %swift.opaque* {{(nocapture|captures\(none\))}} [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUFF:%.*]], i8* [[SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors7MyActorC* [[ACTOR]], %swift.type* [[DECODER_TYPE:%.*]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 
 // CHECK: [[TYPED_RESULT_BUFF:%.*]] = bitcast i8* [[RESULT_BUFF]] to %TSi*
@@ -243,11 +245,12 @@ public distributed actor MyOtherActor {
 // CHECK-SAME: %swift.context* [[THUNK_CONTEXT_PTR]],
 // CHECK-SAME: i32 [[STR_ARG_SIZE]],
 // CHECK-SAME: i32 [[STR_ARG_VAL]],
-// CHECK_SAME: i32 [[STR_ARG_FLAGS]],
+// CHECK-SAME: i32 [[STR_ARG_FLAGS]],
 // CHECK-SAME: %T27distributed_actor_accessors7MyActorC* [[ACTOR]])
 
 // CHECK-NEXT: [[TASK_REF:%.*]] = extractvalue { i8*, i32, %swift.error* } [[THUNK_RESULT]], 0
-// CHECK-NEXT: {{.*}} = call i8* @__swift_async_resume_project_context(i8* [[TASK_REF]])
+// CHECK-NEXT: [[CALLER_ASYNC_CTXT:%.*]] = load ptr, ptr [[TASK_REF]]
+// CHECK-NEXT:  store ptr [[CALLER_ASYNC_CTXT]], ptr
 // CHECK: [[INT_RES:%.*]] = extractvalue { i8*, i32, %swift.error* } [[THUNK_RESULT]], 1
 // CHECK: %._value = getelementptr inbounds %TSi, %TSi* [[TYPED_RESULT_BUFF]], i32 0, i32 0
 // CHECK: store i32 [[INT_RES]], i32* %._value
@@ -257,7 +260,7 @@ public distributed actor MyOtherActor {
 
 // CHECK: define hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC16single_case_enumyAA7SimpleEOAFYaKFTE"
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC16single_case_enumyAA7SimpleEOAFYaKFTETF"(%swift.context* swiftasync %0, %swift.opaque* nocapture [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUFF:%.*]], i8* [[SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors7MyActorC* [[ACTOR]], %swift.type* [[DECODER_TYPE]], %swift.type* [[ACTOR_TYPE]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC16single_case_enumyAA7SimpleEOAFYaKFTETF"(%swift.context* swiftasync %0, %swift.opaque* {{(nocapture|captures\(none\))}} [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUFF:%.*]], i8* [[SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors7MyActorC* [[ACTOR]], %swift.type* [[DECODER_TYPE]], %swift.type* [[ACTOR_TYPE]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 /// Let's check that the call doesn't have any arguments and returns nothing.
 
@@ -292,7 +295,8 @@ public distributed actor MyOtherActor {
 
 // CHECK: [[THUNK_RESULT:%.*]] = call { i8*, i32, %swift.error* } (i32, i8*, i8*, ...) @llvm.coro.suspend.async.sl_p0i8i32p0s_swift.errorss({{.*}}, %swift.context* {{.*}}, i32 [[NATIVE_ENUM_VAL]], i32 [[NATIVE_INT_VAL]], %T27distributed_actor_accessors7MyActorC* {{.*}})
 // CHECK-NEXT: [[TASK_REF:%.*]] = extractvalue { i8*, i32, %swift.error* } [[THUNK_RESULT]], 0
-// CHECK-NEXT: {{.*}} = call i8* @__swift_async_resume_project_context(i8* [[TASK_REF]])
+// CHECK-NEXT: [[CALLER_ASYNC_CTXT:%.*]] = load ptr, ptr [[TASK_REF]]
+// CHECK-NEXT:  store ptr [[CALLER_ASYNC_CTXT]], ptr
 // CHECK: [[ENUM_RESULT:%.*]] = extractvalue { i8*, i32, %swift.error* } [[THUNK_RESULT]], 1
 // CHECK: [[NATIVE_RESULT_PTR:%.*]] = bitcast %T27distributed_actor_accessors9IndirectEO* [[TYPED_RESULT_BUFF]] to i32*
 // CHECK-NEXT: store i32 [[ENUM_RESULT]], i32* [[NATIVE_RESULT_PTR]]
@@ -303,7 +307,7 @@ public distributed actor MyOtherActor {
 
 // CHECK: define hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7complexyAA11LargeStructVSaySiG_AA3ObjCSSSgAFtYaKFTE"
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7complexyAA11LargeStructVSaySiG_AA3ObjCSSSgAFtYaKFTETF"(%swift.context* swiftasync {{.*}}, %swift.opaque* nocapture [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUFF:%.*]], i8* [[SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors7MyActorC* [[ACTOR]], %swift.type* [[DECODER_TYPE:%.*]], %swift.type* [[ACTOR_TYPE]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7complexyAA11LargeStructVSaySiG_AA3ObjCSSSgAFtYaKFTETF"(%swift.context* swiftasync {{.*}}, %swift.opaque* {{(nocapture|captures\(none\))}} [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUFF:%.*]], i8* [[SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors7MyActorC* [[ACTOR]], %swift.type* [[DECODER_TYPE:%.*]], %swift.type* [[ACTOR_TYPE]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 /// First, let's check that all of the different argument types here are loaded correctly.
 
@@ -362,7 +366,7 @@ public distributed actor MyOtherActor {
 
 /// ---> Accessor for `genericArgs`
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC11genericArgsyyx_Sayq_GtYaKSeRzSERzSeR_SER_r0_lFTETF"(%swift.context* swiftasync %0, %swift.opaque*  nocapture [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUF:%.*]], i8* [[GENERIC_SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors7MyActorC* [[ACTOR:%.*]], %swift.type* [[DECODER_TYPE:%.*]], %swift.type* [[ACTOR_TYPE]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC11genericArgsyyx_Sayq_GtYaKSeRzSERzSeR_SER_r0_lFTETF"(%swift.context* swiftasync %0, %swift.opaque*  {{(nocapture|captures\(none\))}} [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUF:%.*]], i8* [[GENERIC_SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors7MyActorC* [[ACTOR:%.*]], %swift.type* [[DECODER_TYPE:%.*]], %swift.type* [[ACTOR_TYPE]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 /// ---> Load `T`
 
@@ -418,7 +422,7 @@ public distributed actor MyOtherActor {
 
 /// Let's check that there is argument decoding since parameter list is empty
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors12MyOtherActorC5emptyyyYaKFTETF"(%swift.context* swiftasync {{.*}}, %swift.opaque* nocapture [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUFF:%.*]], i8* [[SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors12MyOtherActorC* {{.*}}, %swift.type* [[DECODER_TYPE:%.*]], %swift.type* [[ACTOR_TYPE]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors12MyOtherActorC5emptyyyYaKFTETF"(%swift.context* swiftasync {{.*}}, %swift.opaque* {{(nocapture|captures\(none\))}} [[ARG_DECODER:%.*]], i8* [[ARG_TYPES:%.*]], i8* [[RESULT_BUFF:%.*]], i8* [[SUBS:%.*]], i8* [[WITNESS_TABLES:%.*]], i32 [[NUM_WITNESS_TABLES:%.*]], %T27distributed_actor_accessors12MyOtherActorC* {{.*}}, %swift.type* [[DECODER_TYPE:%.*]], %swift.type* [[ACTOR_TYPE]], i8** [[DECODER_PROTOCOL_WITNESS:%.*]])
 // CHECK-NEXT: entry:
 // CHECK-NEXT: {{.*}} = alloca %swift.context*
 // CHECK-NEXT: %swifterror = alloca %swift.error*
diff --git a/test/Distributed/distributed_actor_accessor_thunks_64bit.swift b/test/Distributed/distributed_actor_accessor_thunks_64bit.swift
index 977e7bb401218..25dd99fb9b864 100644
--- a/test/Distributed/distributed_actor_accessor_thunks_64bit.swift
+++ b/test/Distributed/distributed_actor_accessor_thunks_64bit.swift
@@ -116,15 +116,15 @@ public distributed actor MyOtherActor {
 // CHECK: missing-witness1:
 // CHECK-NEXT: call void @llvm.trap()
 // CHECK-NEXT: unreachable
-// CHECK: call swiftcc void @"$s27FakeDistributedActorSystems0A17InvocationDecoderC18decodeNextArgumentxyKSeRzSERzlF"(ptr noalias sret(%swift.opaque) [[ARG_0_VALUE_BUF]], ptr %arg_type, ptr [[ENCODABLE_WITNESS]], ptr [[DECODABLE_WITNESS]], ptr swiftself [[DECODER]], ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK: call swiftcc void @"$s27FakeDistributedActorSystems0A17InvocationDecoderC18decodeNextArgumentxyKSeRzSERzlF"(ptr noalias sret(%swift.opaque) [[ARG_0_VALUE_BUF]], ptr %arg_type, ptr [[ENCODABLE_WITNESS]], ptr [[DECODABLE_WITNESS]], ptr swiftself [[DECODER]], ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 
 // CHECK: store ptr null, ptr %swifterror
-// CHECK-NEXT: %._value = getelementptr inbounds %TSi, ptr [[ARG_0_VALUE_BUF]], i32 0, i32 0
+// CHECK-NEXT: %._value = getelementptr inbounds{{.*}} %TSi, ptr [[ARG_0_VALUE_BUF]], i32 0, i32 0
 // CHECK-NEXT: [[ARG_VAL:%.*]] = load i64, ptr %._value
 
 /// Setup task context for async call to `simple1` thunk
 
-// CHECK-DIRECT: [[CONTEXT_SIZE:%.*]] = load i32, ptr getelementptr inbounds (%swift.async_func_pointer, ptr @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTETu", i32 0, i32 1)
+// CHECK-DIRECT: [[CONTEXT_SIZE:%.*]] = load i32, ptr getelementptr inbounds{{.*}} (%swift.async_func_pointer, ptr @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTETu", i32 0, i32 1)
 // CHECK-INDIRECT: [[ADDR:%[0-9]+]] = load ptr, ptr inttoptr (i64 and (i64 ptrtoint (ptr @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTETu" to i64), i64 -2) to ptr)
 // CHECK-INDIRECT-NEXT: [[SELECT:%[0-9]+]] = select i1 true, ptr @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTETu", ptr [[ADDR]]
 // CHECK-INDIRECT-NEXT: [[LOAD:%[0-9]+]] = getelementptr inbounds %swift.async_func_pointer, ptr [[SELECT]], i32 0, i32 1
@@ -141,7 +141,8 @@ public distributed actor MyOtherActor {
 // CHECK-SAME: ptr [[ACTOR]])
 
 // CHECK-NEXT: [[TASK_REF:%.*]] = extractvalue { ptr, ptr } [[THUNK_RESULT]], 0
-// CHECK-NEXT: {{.*}} = call ptr @__swift_async_resume_project_context(ptr [[TASK_REF]])
+// CHECK-NEXT: [[CALLER_ASYNC_CTXT:%.*]] = load ptr, ptr [[TASK_REF]]
+// CHECK-NEXT: store ptr [[CALLER_ASYNC_CTXT]], ptr
 // CHECK: {{.*}} = call i1 (ptr, i1, ...) @llvm.coro.end.async({{.*}}, ptr {{.*}}, ptr {{.*}})
 
 /// ---> Thunk and distributed method accessor for `simple2`
@@ -155,7 +156,7 @@ public distributed actor MyOtherActor {
 
 /// Setup task context for async call to `simple2` thunk
 
-// CHECK-DIRECT: [[CONTEXT_SIZE:%.*]] = load i32, ptr getelementptr inbounds (%swift.async_func_pointer, ptr @"$s27distributed_actor_accessors7MyActorC7simple2ySSSiYaKFTETu", i32 0, i32 1)
+// CHECK-DIRECT: [[CONTEXT_SIZE:%.*]] = load i32, ptr getelementptr inbounds{{.*}} (%swift.async_func_pointer, ptr @"$s27distributed_actor_accessors7MyActorC7simple2ySSSiYaKFTETu", i32 0, i32 1)
 // CHECK-INDIRECT: [[ADDR:%[0-9]+]] = load ptr, ptr inttoptr (i64 and (i64 ptrtoint (ptr @"$s27distributed_actor_accessors7MyActorC7simple2ySSSiYaKFTETu" to i64), i64 -2) to ptr), align 8
 // CHECK-INDIRECT-NEXT: [[SELECT:%[0-9]+]] = select i1 true, ptr @"$s27distributed_actor_accessors7MyActorC7simple2ySSSiYaKFTETu", ptr [[ADDR]]
 // CHECK-INDIRECT-NEXT: [[LOAD:%[0-9]+]] = getelementptr inbounds %swift.async_func_pointer, ptr [[SELECT]], i32 0, i32 1
@@ -172,7 +173,8 @@ public distributed actor MyOtherActor {
 // CHECK-SAME: ptr [[ACTOR]])
 
 // CHECK-NEXT: [[TASK_REF:%.*]] = extractvalue { ptr, i64, ptr, ptr } [[THUNK_RESULT]], 0
-// CHECK-NEXT: {{.*}} = call ptr @__swift_async_resume_project_context(ptr [[TASK_REF]])
+// CHECK-NEXT: [[CALLER_ASYNC_CTXT:%.*]] = load ptr, ptr [[TASK_REF]]
+// CHECK-NEXT:  store ptr [[CALLER_ASYNC_CTXT]], ptr
 
 /// Extract information about `String` from result and call `end`
 
@@ -197,7 +199,7 @@ public distributed actor MyOtherActor {
 
 // CHECK: [[ARG_SIZE:%.*]] = and i64 {{.*}}, -16
 // CHECK: [[ARG_BUF:%.*]] = call swiftcc ptr @swift_task_alloc(i64 [[ARG_SIZE]])
-// CHECK: %._guts = getelementptr inbounds %TSS, ptr [[ARG_BUF]], i32 0, i32 0
+// CHECK: %._guts = getelementptr inbounds{{.*}} %TSS, ptr [[ARG_BUF]], i32 0, i32 0
 
 // CHECK: [[STR_SIZE:%.*]] = load i64, ptr %._guts._object._countAndFlagsBits._value
 // CHECK: [[STR_VAL:%.*]] = load ptr, ptr %._guts._object._object
@@ -208,7 +210,7 @@ public distributed actor MyOtherActor {
 // CHECK-INDIRECT-NEXT: [[SELECT:%[0-9]+]] = select i1 true, ptr @"$s27distributed_actor_accessors7MyActorC7simple3ySiSSYaKFTETu", ptr [[ADDR]]
 // CHECK-INDIRECT-NEXT: [[LOAD:%[0-9]+]] = getelementptr inbounds %swift.async_func_pointer, ptr [[SELECT]], i32 0, i32 1
 // CHECK-INDIRECT-NEXT: [[CONTEXT_SIZE:%.*]] = load i32, ptr [[LOAD]]
-// CHECK-DIRECT: [[CONTEXT_SIZE:%.*]] = load i32, ptr getelementptr inbounds (%swift.async_func_pointer, ptr @"$s27distributed_actor_accessors7MyActorC7simple3ySiSSYaKFTETu", i32 0, i32 1)
+// CHECK-DIRECT: [[CONTEXT_SIZE:%.*]] = load i32, ptr getelementptr inbounds{{.*}} (%swift.async_func_pointer, ptr @"$s27distributed_actor_accessors7MyActorC7simple3ySiSSYaKFTETu", i32 0, i32 1)
 // CHECK-NEXT: [[CONTEXT_SIZE_64:%.*]] = zext i32 [[CONTEXT_SIZE]] to i64
 // CHECK-NEXT: [[THUNK_ASYNC_CONTEXT:%.*]] = call swiftcc ptr @swift_task_alloc(i64 [[CONTEXT_SIZE_64]])
 
@@ -222,9 +224,10 @@ public distributed actor MyOtherActor {
 // CHECK-SAME: ptr [[ACTOR]])
 
 // CHECK-NEXT: [[TASK_REF:%.*]] = extractvalue { ptr, i64, ptr } [[THUNK_RESULT]], 0
-// CHECK-NEXT: {{.*}} = call ptr @__swift_async_resume_project_context(ptr [[TASK_REF]])
+// CHECK-NEXT: [[CALLER_ASYNC_CTXT:%.*]] = load ptr, ptr [[TASK_REF]]
+// CHECK-NEXT:  store ptr [[CALLER_ASYNC_CTXT]], ptr
 // CHECK: [[INT_RES:%.*]] = extractvalue { ptr, i64, ptr } [[THUNK_RESULT]], 1
-// CHECK: %._value = getelementptr inbounds %TSi, ptr [[RESULT_BUFF]], i32 0, i32 0
+// CHECK: %._value = getelementptr inbounds{{.*}} %TSi, ptr [[RESULT_BUFF]], i32 0, i32 0
 // CHECK: store i64 [[INT_RES]], ptr %._value
 // CHECK: {{.*}} = call i1 (ptr, i1, ...) @llvm.coro.end.async({{.*}}, ptr {{.*}}, ptr {{.*}})
 
@@ -255,14 +258,15 @@ public distributed actor MyOtherActor {
 // CHECK: [[ARG_1_SIZE:%.*]] = and i64 {{.*}}, -16
 // CHECK-NEXT: [[ARG_1_BUF:%.*]] = call swiftcc ptr @swift_task_alloc(i64 [[ARG_1_SIZE]])
 
-// CHECK: %._value = getelementptr inbounds %TSi, ptr [[ARG_1_BUF]], i32 0, i32 0
+// CHECK: %._value = getelementptr inbounds{{.*}} %TSi, ptr [[ARG_1_BUF]], i32 0, i32 0
 // CHECK-NEXT: [[NATIVE_INT_VAL:%.*]] = load i64, ptr %._value
 
 /// Call distributed thunk with extracted arguments.
 
 // CHECK: [[THUNK_RESULT:%.*]] = call { ptr, i64, ptr } (i32, ptr, ptr, ...) @llvm.coro.suspend.async.sl_p0i64p0s({{.*}}, ptr {{.*}}, i64 [[NATIVE_ENUM_VAL]], i64 [[NATIVE_INT_VAL]], ptr {{.*}})
 // CHECK-NEXT: [[TASK_REF:%.*]] = extractvalue { ptr, i64, ptr } [[THUNK_RESULT]], 0
-// CHECK-NEXT: {{.*}} = call ptr @__swift_async_resume_project_context(ptr [[TASK_REF]])
+// CHECK-NEXT: [[CALLER_ASYNC_CTXT:%.*]] = load ptr, ptr [[TASK_REF]]
+// CHECK-NEXT:  store ptr [[CALLER_ASYNC_CTXT]], ptr
 // CHECK: [[ENUM_RESULT:%.*]] = extractvalue { ptr, i64, ptr } [[THUNK_RESULT]], 1
 // CHECK: store i64 [[ENUM_RESULT]], ptr [[RESULT_BUFF]]
 
@@ -283,7 +287,7 @@ public distributed actor MyOtherActor {
 // CHECK: [[ARG_0_SIZE:%.*]] = and i64 {{.*}}, -16
 // CHECK-NEXT: [[ARG_0_BUF:%.*]] = call swiftcc ptr @swift_task_alloc(i64 [[ARG_0_SIZE]])
 
-// CHECK: %._buffer = getelementptr inbounds %TSa, ptr [[ARG_0_BUF]], i32 0, i32 0
+// CHECK: %._buffer = getelementptr inbounds{{.*}} %TSa, ptr [[ARG_0_BUF]], i32 0, i32 0
 // CHECK: [[NATIVE_ARR_VAL:%.*]] = load ptr, ptr %._buffer._storage
 
 /// -> Obj
@@ -298,9 +302,9 @@ public distributed actor MyOtherActor {
 // CHECK: [[ARG_2_SIZE:%.*]] = and i64 {{.*}}, -16
 // CHECK-NEXT: [[ARG_2_BUF:%.*]] = call swiftcc ptr @swift_task_alloc(i64 [[ARG_2_SIZE]])
 
-// CHECK: [[NATIVE_OPT_VAL_0_PTR:%.*]] = getelementptr inbounds { i64, i64 }, ptr [[ARG_2_BUF]], i32 0, i32 0
+// CHECK: [[NATIVE_OPT_VAL_0_PTR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr [[ARG_2_BUF]], i32 0, i32 0
 // CHECK-NEXT: [[NATIVE_OPT_VAL_0:%.*]] = load i64, ptr [[NATIVE_OPT_VAL_0_PTR]]
-// CHECK-NEXT: [[NATIVE_OPT_VAL_1_PTR:%.*]] = getelementptr inbounds { i64, i64 }, ptr [[ARG_2_BUF]], i32 0, i32 1
+// CHECK-NEXT: [[NATIVE_OPT_VAL_1_PTR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr [[ARG_2_BUF]], i32 0, i32 1
 // CHECK-NEXT: [[NATIVE_OPT_VAL_1:%.*]] = load i64, ptr [[NATIVE_OPT_VAL_1_PTR]]
 
 /// -> LargeStruct (passed indirectly)
@@ -331,8 +335,8 @@ public distributed actor MyOtherActor {
 // CHECK: [[ARG_1_SIZE:%.*]] = and i64 {{.*}}, -16
 // CHECK-NEXT: [[ARG_1_BUF:%.*]] = call swiftcc ptr @swift_task_alloc(i64 [[ARG_1_SIZE]])
 
-// CHECK: %._buffer = getelementptr inbounds %TSa, ptr [[ARG_1_BUF]], i32 0, i32 0
-// CHECK-NEXT: %._buffer._storage = getelementptr inbounds [[ARRAY_TYPE:%.*]], ptr %._buffer, i32 0, i32 0
+// CHECK: %._buffer = getelementptr inbounds{{.*}} %TSa, ptr [[ARG_1_BUF]], i32 0, i32 0
+// CHECK-NEXT: %._buffer._storage = getelementptr inbounds{{.*}} [[ARRAY_TYPE:%.*]], ptr %._buffer, i32 0, i32 0
 // CHECK: [[TYPED_ARG_1:%.*]] = load ptr, ptr %._buffer._storage
 
 /// ---> Load generic argument substitutions from the caller-provided buffer
@@ -376,7 +380,7 @@ public distributed actor MyOtherActor {
 // CHECK-NEXT: {{.*}} = call ptr @llvm.coro.begin(token {{%.*}}, ptr null)
 // CHECK-NEXT: store ptr {{.*}}, ptr {{.*}}
 // CHECK-NEXT: store ptr null, ptr %swifterror
-// CHECK-DIRECT-NEXT: {{.*}} = load i32, ptr getelementptr inbounds (%swift.async_func_pointer, ptr @"$s27distributed_actor_accessors12MyOtherActorC5emptyyyYaKFTETu", i32 0, i32 1)
+// CHECK-DIRECT-NEXT: {{.*}} = load i32, ptr getelementptr inbounds{{.*}} (%swift.async_func_pointer, ptr @"$s27distributed_actor_accessors12MyOtherActorC5emptyyyYaKFTETu", i32 0, i32 1)
 // CHECK-INDIRECT-NEXT: [[ADDR:%[0-9]+]] = load ptr, ptr inttoptr (i64 and (i64 ptrtoint (ptr @"$s27distributed_actor_accessors12MyOtherActorC5emptyyyYaKFTETu" to i64), i64 -2) to ptr), align 8
 // CHECK-INDIRECT-NEXT: [[SELECT:%[0-9]+]] = select i1 true, ptr @"$s27distributed_actor_accessors12MyOtherActorC5emptyyyYaKFTETu", ptr [[ADDR]]
 // CHECK-INDIRECT-NEXT: [[LOAD:%[0-9]+]] = getelementptr inbounds %swift.async_func_pointer, ptr [[SELECT]], i32 0, i32 1
diff --git a/test/Distributed/distributed_actor_adhoc_requirements_optimized_build.swift b/test/Distributed/distributed_actor_adhoc_requirements_optimized_build.swift
index 123f6b4215e62..3bc6c7add1ba8 100644
--- a/test/Distributed/distributed_actor_adhoc_requirements_optimized_build.swift
+++ b/test/Distributed/distributed_actor_adhoc_requirements_optimized_build.swift
@@ -1,19 +1,16 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-ir -swift-version 6 -O -I %t %s
-// RUN: %target-swift-frontend -emit-sil -swift-version 6 -O -I %t %s | %FileCheck %s
+// RUN: %target-swift-frontend -target %target-swift-6.0-abi-triple -emit-ir -swift-version 6 -O -I %t %s
+// RUN: %target-swift-frontend -target %target-swift-6.0-abi-triple -emit-sil -swift-version 6 -O -I %t %s | %FileCheck %s
 
 // REQUIRES: concurrency
 // REQUIRES: distributed
 
-// REQUIRES: OS=macosx || OS=ios
-
 import Distributed
 
-// NOTE: None of the ad-hoc protocol requirement implementations
-
 public protocol Transferable: Sendable {}
 
 // NOT final on purpose
+@available(SwiftStdlib 5.7, *)
 public class TheSpecificResultHandlerWhichIsANonFinalClass: DistributedTargetInvocationResultHandler {
   public typealias SerializationRequirement = Transferable
 
@@ -30,6 +27,7 @@ public class TheSpecificResultHandlerWhichIsANonFinalClass: DistributedTargetInv
 }
 
 // NOT final on purpose
+@available(SwiftStdlib 5.7, *)
 public class FakeInvocationDecoder: DistributedTargetInvocationDecoder {
   public typealias SerializationRequirement = Transferable
 
@@ -51,6 +49,7 @@ public class FakeInvocationDecoder: DistributedTargetInvocationDecoder {
 }
 
 // NOT final on purpose
+@available(SwiftStdlib 5.7, *)
 public class FakeInvocationEncoder : DistributedTargetInvocationEncoder {
   public typealias SerializationRequirement = Transferable
 
@@ -72,6 +71,7 @@ public class FakeInvocationEncoder : DistributedTargetInvocationEncoder {
 }
 
 // NOT final on purpose
+@available(SwiftStdlib 5.7, *)
 public class NotFinalActorSystemForAdHocRequirementTest: DistributedActorSystem, @unchecked Sendable {
   public typealias ActorID = String
   public typealias InvocationEncoder = FakeInvocationEncoder
diff --git a/test/Distributed/distributed_actor_derived_conformances.swift b/test/Distributed/distributed_actor_derived_conformances.swift
index 056e3f31baea8..59e7743e12f8b 100644
--- a/test/Distributed/distributed_actor_derived_conformances.swift
+++ b/test/Distributed/distributed_actor_derived_conformances.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-5.7-abi-triple %S/Inputs/FakeDistributedActorSystems.swift
-// RUN: %target-typecheck-verify-swift -target %target-swift-5.7-abi-triple -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -target %target-swift-5.7-abi-triple -I %t
 // REQUIRES: concurrency
 // REQUIRES: distributed
 
diff --git a/test/Distributed/distributed_actor_executor_ast.swift b/test/Distributed/distributed_actor_executor_ast.swift
index 9aeaabe44480f..e225df4bcd050 100644
--- a/test/Distributed/distributed_actor_executor_ast.swift
+++ b/test/Distributed/distributed_actor_executor_ast.swift
@@ -6,7 +6,7 @@
 // REQUIRES: concurrency
 // REQUIRES: distributed
 
-// REQUIRES: rdar114453974
+// REQUIRES: rdar114198425
 
 // rdar://76038845
 // UNSUPPORTED: use_os_stdlib
diff --git a/test/Distributed/distributed_actor_func_implicitly_async_throws.swift b/test/Distributed/distributed_actor_func_implicitly_async_throws.swift
index 97bd1669f11e6..7840b71296243 100644
--- a/test/Distributed/distributed_actor_func_implicitly_async_throws.swift
+++ b/test/Distributed/distributed_actor_func_implicitly_async_throws.swift
@@ -25,66 +25,55 @@ distributed actor D {
 func test_not_distributed_funcs(distributed: D) async {
   distributed.hello() // expected-error{{only 'distributed' instance methods can be called on a potentially remote distributed actor}}
   distributed.helloAsync() // expected-error{{only 'distributed' instance methods can be called on a potentially remote distributed actor}}
-  // expected-error@-1{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-2{{call is 'async'}}
-  // {{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
+  // expected-error@-1{{actor-isolated instance method 'helloAsync()' cannot be called from outside of the actor}} {{3-3=await }}
   distributed.helloAsyncThrows() // expected-error{{only 'distributed' instance methods can be called on a potentially remote distributed actor}}
-  // expected-error@-1{{expression is 'async' but is not marked with 'await'}} // TODO: no need to diagnose this, it is impossible to call anyway
-  // expected-note@-2{{call is 'async'}}
-  // expected-error@-3{{call can throw, but it is not marked with 'try' and the error is not handled}} // TODO: no need to diagnose this, it is impossible to call anyway
+  // expected-error@-1{{actor-isolated instance method 'helloAsyncThrows()' cannot be called from outside of the actor}} // TODO: no need to diagnose this, it is impossible to call anyway
+  // expected-error@-2{{call can throw, but it is not marked with 'try' and the error is not handled}} // TODO: no need to diagnose this, it is impossible to call anyway
 }
 
 func test_outside(distributed: D) async throws {
-  distributed.distHello() // expected-error{{expression is 'async' but is not marked with 'await'}}
+  distributed.distHello() // expected-error{{actor-isolated distributed instance method 'distHello()' cannot be called from outside of the actor}}
   // expected-error@-1{{call can throw but is not marked with 'try'}}
-  // expected-note@-2{{calls to distributed instance method 'distHello()' from outside of its actor context are implicitly asynchronous}}
-  // expected-note@-3{{did you mean to use 'try'?}}
-  // expected-note@-4{{did you mean to disable error propagation?}}
-  // expected-note@-5{{did you mean to handle error as optional value?}}
-  try distributed.distHello() // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{calls to distributed instance method 'distHello()' from outside of its actor context are implicitly asynchronous}}
+  // expected-note@-2{{did you mean to use 'try'?}}
+  // expected-note@-3{{did you mean to disable error propagation?}}
+  // expected-note@-4{{did you mean to handle error as optional value?}}
+  try distributed.distHello() // expected-error{{ctor-isolated distributed instance method 'distHello()' cannot be called from outside of the actor}}
   await distributed.distHello() // expected-error{{call can throw but is not marked with 'try'}}
   // expected-note@-1{{did you mean to use 'try'?}}
   // expected-note@-2{{did you mean to disable error propagation?}}
   // expected-note@-3{{did you mean to handle error as optional value?}}
   try await distributed.distHello() // ok
 
-  distributed.distHelloAsync()// expected-error{{expression is 'async' but is not marked with 'await'}}
+  distributed.distHelloAsync()// expected-error{{actor-isolated distributed instance method 'distHelloAsync()' cannot be called from outside of the actor}}
   // expected-error@-1{{call can throw but is not marked with 'try'}}
-  // expected-note@-2{{calls to distributed instance method 'distHelloAsync()' from outside of its actor context are implicitly asynchronous}}
-  // expected-note@-3{{did you mean to use 'try'?}}
-  // expected-note@-4{{did you mean to disable error propagation?}}
-  // expected-note@-5{{did you mean to handle error as optional value?}}
-  try distributed.distHelloAsync() // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{calls to distributed instance method 'distHelloAsync()' from outside of its actor context are implicitly asynchronous}}
+  // expected-note@-2{{did you mean to use 'try'?}}
+  // expected-note@-3{{did you mean to disable error propagation?}}
+  // expected-note@-4{{did you mean to handle error as optional value?}}
+  try distributed.distHelloAsync() // expected-error{{actor-isolated distributed instance method 'distHelloAsync()' cannot be called from outside of the actor}}
   await distributed.distHelloAsync() // expected-error{{call can throw but is not marked with 'try'}}
   // expected-note@-1{{did you mean to use 'try'?}}
   // expected-note@-2{{did you mean to disable error propagation?}}
   // expected-note@-3{{did you mean to handle error as optional value?}}
   try await distributed.distHelloAsync() // ok
 
-  distributed.distHelloThrows() // expected-error{{expression is 'async' but is not marked with 'await'}}
+  distributed.distHelloThrows() // expected-error{{actor-isolated distributed instance method 'distHelloThrows()' cannot be called from outside of the actor}}
   // expected-error@-1{{call can throw but is not marked with 'try'}}
-  // expected-note@-2{{calls to distributed instance method 'distHelloThrows()' from outside of its actor context are implicitly asynchronous}}
-  // expected-note@-3{{did you mean to use 'try'?}}
-  // expected-note@-4{{did you mean to disable error propagation?}}
-  // expected-note@-5{{did you mean to handle error as optional value?}}
-  try distributed.distHelloThrows() // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{calls to distributed instance method 'distHelloThrows()' from outside of its actor context are implicitly asynchronous}}
+  // expected-note@-2{{did you mean to use 'try'?}}
+  // expected-note@-3{{did you mean to disable error propagation?}}
+  // expected-note@-4{{did you mean to handle error as optional value?}}
+  try distributed.distHelloThrows() // expected-error{{actor-isolated distributed instance method 'distHelloThrows()' cannot be called from outside of the actor}}
   await distributed.distHelloThrows() // expected-error{{call can throw but is not marked with 'try'}}
   // expected-note@-1{{did you mean to use 'try'?}}
   // expected-note@-2{{did you mean to disable error propagation?}}
   // expected-note@-3{{did you mean to handle error as optional value?}}
   try await distributed.distHelloThrows() // ok
 
-  distributed.distHelloAsyncThrows() // expected-error{{expression is 'async' but is not marked with 'await'}}
+  distributed.distHelloAsyncThrows() // expected-error{{actor-isolated distributed instance method 'distHelloAsyncThrows()' cannot be called from outside of the actor}}
   // expected-error@-1{{call can throw but is not marked with 'try'}}
-  // expected-note@-2{{calls to distributed instance method 'distHelloAsyncThrows()' from outside of its actor context are implicitly asynchronous}}
-  // expected-note@-3{{did you mean to use 'try'?}}
-  // expected-note@-4{{did you mean to disable error propagation?}}
-  // expected-note@-5{{did you mean to handle error as optional value?}}
-  try distributed.distHelloAsyncThrows() // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{calls to distributed instance method 'distHelloAsyncThrows()' from outside of its actor context are implicitly asynchronous}}
+  // expected-note@-2{{did you mean to use 'try'?}}
+  // expected-note@-3{{did you mean to disable error propagation?}}
+  // expected-note@-4{{did you mean to handle error as optional value?}}
+  try distributed.distHelloAsyncThrows() // expected-error{{actor-isolated distributed instance method 'distHelloAsyncThrows()' cannot be called from outside of the actor}}
   await distributed.distHelloAsyncThrows() // expected-error{{call can throw but is not marked with 'try'}}
   // expected-note@-1{{did you mean to use 'try'?}}
   // expected-note@-2{{did you mean to disable error propagation?}}
diff --git a/test/Distributed/distributed_actor_isolation_and_tasks.swift b/test/Distributed/distributed_actor_isolation_and_tasks.swift
index 7498011441d74..94400388cf835 100644
--- a/test/Distributed/distributed_actor_isolation_and_tasks.swift
+++ b/test/Distributed/distributed_actor_isolation_and_tasks.swift
@@ -54,8 +54,7 @@ distributed actor Philosopher {
       // because we KNOW this is a local call -- and there is no system in
       // between that will throw.
       _ = await self.dist() // notice lack of 'try' even though 'distributed func'
-      _ = self.variable_fromDetach // expected-error{{expression is 'async' but is not marked with 'await'}}
-      // expected-note@-1{{property access is 'async'}}
+      _ = self.variable_fromDetach // expected-error{{actor-isolated property 'variable_fromDetach' cannot be accessed from outside of the actor}} {{11-11=await }}
       _ = await self.variable_fromDetach // okay, we know we're on the local node
     }
   }
diff --git a/test/Distributed/distributed_actor_nonisolated.swift b/test/Distributed/distributed_actor_nonisolated.swift
index ddac071375d72..f47c7611df072 100644
--- a/test/Distributed/distributed_actor_nonisolated.swift
+++ b/test/Distributed/distributed_actor_nonisolated.swift
@@ -10,6 +10,10 @@ import FakeDistributedActorSystems
 @available(SwiftStdlib 5.5, *)
 typealias DefaultDistributedActorSystem = FakeActorSystem
 
+@propertyWrapper struct P {
+  var wrappedValue = 0
+}
+
 distributed actor DA {
 
   let local: Int = 42
@@ -49,6 +53,9 @@ distributed actor DA {
     fatalError()
   }
 
+  nonisolated lazy var a = 0 // expected-error {{'nonisolated' can not be applied to distributed actor stored properties}}
+  @P nonisolated var b = 0 // expected-error {{'nonisolated' can not be applied to distributed actor stored properties}}
+
 }
 
 func invalidIsolatedCall<DA: DistributedActor> (
diff --git a/test/Distributed/distributed_actor_system_missing.swift b/test/Distributed/distributed_actor_system_missing.swift
index 9c5d989418be7..b5129ce8a5481 100644
--- a/test/Distributed/distributed_actor_system_missing.swift
+++ b/test/Distributed/distributed_actor_system_missing.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -enable-experimental-distributed -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -enable-experimental-distributed -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
 
 // UNSUPPORTED: back_deploy_concurrency
 // REQUIRES: concurrency
diff --git a/test/Distributed/distributed_actor_system_missing_adhoc_requirement_fixits.swift b/test/Distributed/distributed_actor_system_missing_adhoc_requirement_fixits.swift
index 972ee4f025318..327e790013f55 100644
--- a/test/Distributed/distributed_actor_system_missing_adhoc_requirement_fixits.swift
+++ b/test/Distributed/distributed_actor_system_missing_adhoc_requirement_fixits.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
 
 // UNSUPPORTED: back_deploy_concurrency
 // REQUIRES: concurrency
diff --git a/test/Distributed/distributed_actor_system_missing_adhoc_requirement_impls.swift b/test/Distributed/distributed_actor_system_missing_adhoc_requirement_impls.swift
index 16428f4d61c77..9bfdc254298c3 100644
--- a/test/Distributed/distributed_actor_system_missing_adhoc_requirement_impls.swift
+++ b/test/Distributed/distributed_actor_system_missing_adhoc_requirement_impls.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
 
 // UNSUPPORTED: back_deploy_concurrency
 // REQUIRES: concurrency
diff --git a/test/Distributed/distributed_actor_system_missing_system_type.swift b/test/Distributed/distributed_actor_system_missing_system_type.swift
index ab06e61c78976..9984db3ea7a68 100644
--- a/test/Distributed/distributed_actor_system_missing_system_type.swift
+++ b/test/Distributed/distributed_actor_system_missing_system_type.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -enable-experimental-distributed -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -enable-experimental-distributed -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
 
 // UNSUPPORTED: back_deploy_concurrency
 // REQUIRES: concurrency
diff --git a/test/Distributed/distributed_actor_system_missing_type_no_crash.swift b/test/Distributed/distributed_actor_system_missing_type_no_crash.swift
index d8c9e6518d8b6..b6f52d384c478 100644
--- a/test/Distributed/distributed_actor_system_missing_type_no_crash.swift
+++ b/test/Distributed/distributed_actor_system_missing_type_no_crash.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
 
 // UNSUPPORTED: back_deploy_concurrency
 // REQUIRES: concurrency
diff --git a/test/Distributed/distributed_actor_system_serialization_requirement_any.swift b/test/Distributed/distributed_actor_system_serialization_requirement_any.swift
new file mode 100644
index 0000000000000..5fbd7574ee523
--- /dev/null
+++ b/test/Distributed/distributed_actor_system_serialization_requirement_any.swift
@@ -0,0 +1,97 @@
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+
+// UNSUPPORTED: back_deploy_concurrency
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+import Distributed
+
+final class CrashActorSystem: DistributedActorSystem {
+  typealias ActorID = CrashActorID
+  typealias InvocationEncoder = CrashInvocationEncoder
+  typealias InvocationDecoder = CrashInvocationDecoder
+  typealias ResultHandler = CrashResultHandler
+
+  typealias SerializationRequirement = Any
+
+  func assignID<Actor: DistributedActor>(_: Actor.Type) -> ActorID where Actor.ID == ActorID {
+    fatalError()
+  }
+
+  func resignID(_: ActorID) {
+    // nothing
+  }
+
+  func actorReady<Actor: DistributedActor>(_: Actor) where Actor.ID == ActorID { }
+
+  func resolve<Actor: DistributedActor>(id _: ActorID, as _: Actor.Type) throws -> Actor? where Actor.ID == ActorID {
+    return nil
+  }
+
+  func makeInvocationEncoder() -> InvocationEncoder {
+    return InvocationEncoder()
+  }
+
+  func remoteCallVoid<Actor: DistributedActor, Failure: Error>(
+    on _: Actor,
+    target _: RemoteCallTarget,
+    invocation _: inout InvocationEncoder,
+    throwing _: Failure.Type
+  ) async throws where Actor.ID == ActorID {
+    return
+  }
+
+  func remoteCall<Actor: DistributedActor, Failure: Error, Success: SerializationRequirement>(
+    on _: Actor,
+    target _: RemoteCallTarget,
+    invocation _: inout InvocationEncoder,
+    throwing _: Failure.Type,
+    returning _: Success.Type
+  ) async throws -> Success where Actor.ID == ActorID {
+    fatalError()
+  }
+
+}
+
+struct CrashActorID: Hashable {
+  func hash(into hasher: inout Hasher) { }
+}
+
+struct CrashInvocationEncoder: DistributedTargetInvocationEncoder {
+  typealias SerializationRequirement = CrashActorSystem.SerializationRequirement
+
+  func recordGenericSubstitution<GenericSubstitution>(_: GenericSubstitution.Type) throws { }
+  mutating func recordArgument<Argument: SerializationRequirement>(_: RemoteCallArgument<Argument>) throws { }
+  mutating func recordReturnType<Success: SerializationRequirement>(_: Success.Type) throws { }
+  func recordErrorType<Failure: Error>(_: Failure.Type) throws { }
+  func doneRecording() throws { }
+}
+
+struct CrashInvocationDecoder: DistributedTargetInvocationDecoder {
+  typealias SerializationRequirement = CrashActorSystem.SerializationRequirement
+
+  func decodeGenericSubstitutions() throws -> [Any.Type] {
+    return []
+  }
+
+  mutating func decodeNextArgument<Argument: SerializationRequirement>() throws -> Argument {
+    fatalError()
+  }
+
+  func decodeReturnType() throws -> Any.Type? {
+    return nil
+  }
+
+  func decodeErrorType() throws -> Any.Type? {
+    return nil
+  }
+
+}
+
+struct CrashResultHandler: DistributedTargetInvocationResultHandler {
+  typealias SerializationRequirement = CrashActorSystem.SerializationRequirement
+
+  func onReturn<Success: SerializationRequirement>(value _: Success) async throws { }
+  func onReturnVoid() async throws { }
+  func onThrow<Failure: Error>(error _: Failure) async throws { }
+}
\ No newline at end of file
diff --git a/test/Distributed/distributed_actor_to_actor.swift b/test/Distributed/distributed_actor_to_actor.swift
index c58211e86aba5..f1b1eb0cb47d6 100644
--- a/test/Distributed/distributed_actor_to_actor.swift
+++ b/test/Distributed/distributed_actor_to_actor.swift
@@ -32,7 +32,7 @@ func getAnyActor(distributedActor: isolated some DistributedActor) -> any Actor
 
 // CHECK-IR-LABEL: define {{.*}} @"$s021distributed_actor_to_B011getAnyActor0aF0ScA_pxYi_t11Distributed0gF0RzlF
 // CHECK-IR: %conditional.requirement.buffer = alloca [1 x ptr]
-// CHECK-IR: [[CONDITIONAL_REQ_GEP:%[0-9]+]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-IR: [[CONDITIONAL_REQ_GEP:%[0-9]+]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-IR-NEXT: [[SELF_DA_REQ:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQ_GEP]], i32 0
 // CHECK-IR-NEXT: store ptr %"some DistributedActor.DistributedActor", ptr [[SELF_DA_REQ]]
 // CHECK-IR-NEXT: call ptr @swift_getWitnessTable(ptr @"$sxScA11DistributedMc{{(.ptrauth)?}}", ptr %"some DistributedActor", ptr [[CONDITIONAL_REQ_GEP]])
diff --git a/test/Distributed/distributed_actor_transfernonsendable.swift b/test/Distributed/distributed_actor_transfernonsendable.swift
index 03bd59365c3a6..3b720c914364c 100644
--- a/test/Distributed/distributed_actor_transfernonsendable.swift
+++ b/test/Distributed/distributed_actor_transfernonsendable.swift
@@ -59,10 +59,21 @@ distributed actor MyDistributedActor {
 
   distributed func transferActorIsolatedArgIntoClosure(_ x: NonSendableKlass) async {
     _ = { @MainActor in
-      // TODO: In 2nd part of message should say actor-isolated instead of later
-      // nonisolated uses in the case of a closure.
       print(x) // expected-error {{sending 'x' risks causing data races}}
-      // expected-note @-1 {{'self'-isolated 'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+      // expected-note @-1 {{'self'-isolated 'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later actor-isolated uses}}
+    }
+  }
+
+
+  func doSomething() async { }
+
+  // Make sure that we consider asLocalActor's result to be the same actor as
+  // its actor parameter.
+  func testAsLocalActorForwards() async {
+    await withTaskGroup { group in
+      group.addTask {
+        await self.doSomething()
+      }
     }
   }
 }
diff --git a/test/Distributed/distributed_incomplete_system_no_crash.swift b/test/Distributed/distributed_incomplete_system_no_crash.swift
index 431e1474f74ec..01b6461094673 100644
--- a/test/Distributed/distributed_incomplete_system_no_crash.swift
+++ b/test/Distributed/distributed_incomplete_system_no_crash.swift
@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.7-abi-triple 2>&1 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -target %target-swift-5.7-abi-triple 2>&1 %s
 
 // REQUIRES: concurrency
 // REQUIRES: distributed
diff --git a/test/Distributed/distributed_property_must_be_throws.swift b/test/Distributed/distributed_property_must_be_throws.swift
index ef5b7c021fc26..53ae68e203d95 100644
--- a/test/Distributed/distributed_property_must_be_throws.swift
+++ b/test/Distributed/distributed_property_must_be_throws.swift
@@ -22,8 +22,7 @@ func test(da: MyDistributedActor) async throws {
   // expected-note@-2{{did you mean to handle error as optional value?}}
   // expected-note@-3{{did you mean to disable error propagation?}}
 
-  _ = try da.distributedProperty // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{property access is 'async'}}
+  _ = try da.distributedProperty // expected-error{{actor-isolated distributed property 'distributedProperty' cannot be accessed from outside of the actor}} {{11-11=await }}
 
   _ = try await da.distributedProperty // ok, implicitly async + throws
 }
diff --git a/test/Distributed/distributed_protocols_distributed_func_serialization_requirements.swift b/test/Distributed/distributed_protocols_distributed_func_serialization_requirements.swift
index f169c98a307a7..c87c5b3b3aa69 100644
--- a/test/Distributed/distributed_protocols_distributed_func_serialization_requirements.swift
+++ b/test/Distributed/distributed_protocols_distributed_func_serialization_requirements.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-5.7-abi-triple %S/Inputs/FakeDistributedActorSystems.swift
-// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unknown -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -verify-ignore-unknown -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
 // REQUIRES: concurrency
 // REQUIRES: distributed
 
diff --git a/test/Distributed/distributed_public_module_import.swift b/test/Distributed/distributed_public_module_import.swift
new file mode 100644
index 0000000000000..54afbfc5c0e8d
--- /dev/null
+++ b/test/Distributed/distributed_public_module_import.swift
@@ -0,0 +1,14 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-5.7-abi-triple %S/Inputs/FakeDistributedActorSystems.swift
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+// Should NOT produce a warning, we do use the module in a public declaration, see MyPublicDistributedActor
+public import Distributed
+import FakeDistributedActorSystems
+
+
+public distributed actor MyPublicDistributedActor {
+  public typealias ActorSystem = FakeActorSystem
+}
diff --git a/test/Distributed/distributed_serializationRequirement_must_be_protocol.swift b/test/Distributed/distributed_serializationRequirement_must_be_protocol.swift
index 6c68b72aadb6b..24bad38d3c72f 100644
--- a/test/Distributed/distributed_serializationRequirement_must_be_protocol.swift
+++ b/test/Distributed/distributed_serializationRequirement_must_be_protocol.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-5.7-abi-triple %S/Inputs/FakeDistributedActorSystems.swift
-// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unknown -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -verify-ignore-unknown -target %target-swift-5.7-abi-triple -I %t 2>&1 %s
 // REQUIRES: concurrency
 // REQUIRES: distributed
 
@@ -54,7 +54,7 @@ final class System: DistributedActorSystem {
     fatalError()
   }
 
-  // expected-note@+1 {{candidate has non-matching type '<Act, Err, Res> (on: Act, target: RemoteCallTarget, invocation: inout System.InvocationEncoder, throwing: Err.Type, returning: Res.Type) async throws -> Res' (aka '<Act, Err, Res> (on: Act, target: RemoteCallTarget, invocation: inout ClassInvocationEncoder, throwing: Err.Type, returning: Res.Type) async throws -> Res') [with ResultHandler = <<error type>>]}}
+  // expected-note@+1 {{candidate has non-matching type '<Act, Err, Res> (on: Act, target: RemoteCallTarget, invocation: inout System.InvocationEncoder, throwing: Err.Type, returning: Res.Type) async throws -> Res' (aka '<Act, Err, Res> (on: Act, target: RemoteCallTarget, invocation: inout ClassInvocationEncoder, throwing: Err.Type, returning: Res.Type) async throws -> Res') [with ResultHandler = _]}}
   func remoteCall<Act, Err, Res>(
     on actor: Act,
     target: RemoteCallTarget,
diff --git a/test/Driver/baremetal-target.swift b/test/Driver/baremetal-target.swift
index 0e200f3f83116..b377fd8f16882 100644
--- a/test/Driver/baremetal-target.swift
+++ b/test/Driver/baremetal-target.swift
@@ -1,4 +1,4 @@
 // RUN: %swiftc_driver_plain -target aarch64-unknown-none-none -driver-print-jobs %s 2>&1 | %FileCheck %s
 
 // CHECK: {{.*}}swift{{c|c-legacy-driver|-frontend}}{{(.exe)?"?}} -frontend -c
-// CHECK: {{.*}}clang{{(.exe)?"?}} -fuse-ld=gold
+// CHECK: {{.*}}clang{{(.exe)?"?}}
diff --git a/test/Driver/batch_mode.swift b/test/Driver/batch_mode.swift
deleted file mode 100644
index 0607375d0aa52..0000000000000
--- a/test/Driver/batch_mode.swift
+++ /dev/null
@@ -1,138 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: touch %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/file-04.swift %t/file-05.swift
-// RUN: touch %t/file-06.swift %t/file-07.swift %t/file-08.swift %t/file-09.swift %t/file-10.swift
-// RUN: touch %t/file-11.swift %t/file-12.swift %t/file-13.swift %t/file-14.swift %t/file-15.swift
-// RUN: touch %t/file-16.swift %t/file-17.swift %t/file-18.swift %t/file-19.swift %t/file-20.swift
-// RUN: touch %t/file-21.swift %t/file-22.swift %t/file-23.swift %t/file-24.swift %t/file-25.swift
-// RUN: touch %t/file-26.swift %t/file-27.swift %t/file-28.swift %t/file-29.swift %t/file-30.swift
-//
-// RUN: %swiftc_driver -enable-batch-mode -driver-show-job-lifecycle -driver-skip-execution -j 4 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/file-04.swift %t/file-05.swift %t/file-06.swift %t/file-07.swift %t/file-08.swift %t/file-09.swift %t/file-10.swift %t/file-11.swift %t/file-12.swift %t/file-13.swift %t/file-14.swift %t/file-15.swift %t/file-16.swift %t/file-17.swift %t/file-18.swift %t/file-19.swift %t/file-20.swift %t/file-21.swift %t/file-22.swift %t/file-23.swift %t/file-24.swift %t/file-25.swift %t/file-26.swift %t/file-27.swift %t/file-28.swift %t/file-29.swift %t/file-30.swift | %FileCheck %s -check-prefix=SEED0
-//
-// RUN: %swiftc_driver -enable-batch-mode -driver-show-job-lifecycle -driver-skip-execution -j 4 -driver-batch-seed 1 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/file-04.swift %t/file-05.swift %t/file-06.swift %t/file-07.swift %t/file-08.swift %t/file-09.swift %t/file-10.swift %t/file-11.swift %t/file-12.swift %t/file-13.swift %t/file-14.swift %t/file-15.swift %t/file-16.swift %t/file-17.swift %t/file-18.swift %t/file-19.swift %t/file-20.swift %t/file-21.swift %t/file-22.swift %t/file-23.swift %t/file-24.swift %t/file-25.swift %t/file-26.swift %t/file-27.swift %t/file-28.swift %t/file-29.swift %t/file-30.swift | %FileCheck %s -check-prefix=SEED1
-//
-// RUN: %swiftc_driver -enable-batch-mode -driver-show-job-lifecycle -driver-skip-execution -j 4 -driver-batch-seed 2 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/file-04.swift %t/file-05.swift %t/file-06.swift %t/file-07.swift %t/file-08.swift %t/file-09.swift %t/file-10.swift %t/file-11.swift %t/file-12.swift %t/file-13.swift %t/file-14.swift %t/file-15.swift %t/file-16.swift %t/file-17.swift %t/file-18.swift %t/file-19.swift %t/file-20.swift %t/file-21.swift %t/file-22.swift %t/file-23.swift %t/file-24.swift %t/file-25.swift %t/file-26.swift %t/file-27.swift %t/file-28.swift %t/file-29.swift %t/file-30.swift | %FileCheck %s -check-prefix=SEED2
-//
-// 30 files / 4 batches => 2 batches of 8 jobs + 2 batches of 7 jobs
-//
-// SEED0: Found 30 batchable jobs
-// SEED0: Forming into 4 batches
-// SEED0: Adding {compile: {{file-01-.*}} <= file-01.swift} to batch 0
-// SEED0: Adding {compile: {{file-02-.*}} <= file-02.swift} to batch 0
-// SEED0: Adding {compile: {{file-03-.*}} <= file-03.swift} to batch 0
-// SEED0: Adding {compile: {{file-04-.*}} <= file-04.swift} to batch 0
-// SEED0: Adding {compile: {{file-05-.*}} <= file-05.swift} to batch 0
-// SEED0: Adding {compile: {{file-06-.*}} <= file-06.swift} to batch 0
-// SEED0: Adding {compile: {{file-07-.*}} <= file-07.swift} to batch 0
-// SEED0: Adding {compile: {{file-08-.*}} <= file-08.swift} to batch 0
-// SEED0: Adding {compile: {{file-09-.*}} <= file-09.swift} to batch 1
-// SEED0: Adding {compile: {{file-10-.*}} <= file-10.swift} to batch 1
-// SEED0: Adding {compile: {{file-11-.*}} <= file-11.swift} to batch 1
-// SEED0: Adding {compile: {{file-12-.*}} <= file-12.swift} to batch 1
-// SEED0: Adding {compile: {{file-13-.*}} <= file-13.swift} to batch 1
-// SEED0: Adding {compile: {{file-14-.*}} <= file-14.swift} to batch 1
-// SEED0: Adding {compile: {{file-15-.*}} <= file-15.swift} to batch 1
-// SEED0: Adding {compile: {{file-16-.*}} <= file-16.swift} to batch 1
-// SEED0: Adding {compile: {{file-17-.*}} <= file-17.swift} to batch 2
-// SEED0: Adding {compile: {{file-18-.*}} <= file-18.swift} to batch 2
-// SEED0: Adding {compile: {{file-19-.*}} <= file-19.swift} to batch 2
-// SEED0: Adding {compile: {{file-20-.*}} <= file-20.swift} to batch 2
-// SEED0: Adding {compile: {{file-21-.*}} <= file-21.swift} to batch 2
-// SEED0: Adding {compile: {{file-22-.*}} <= file-22.swift} to batch 2
-// SEED0: Adding {compile: {{file-23-.*}} <= file-23.swift} to batch 2
-// SEED0: Adding {compile: {{file-24-.*}} <= file-24.swift} to batch 3
-// SEED0: Adding {compile: {{file-25-.*}} <= file-25.swift} to batch 3
-// SEED0: Adding {compile: {{file-26-.*}} <= file-26.swift} to batch 3
-// SEED0: Adding {compile: {{file-27-.*}} <= file-27.swift} to batch 3
-// SEED0: Adding {compile: {{file-28-.*}} <= file-28.swift} to batch 3
-// SEED0: Adding {compile: {{file-29-.*}} <= file-29.swift} to batch 3
-// SEED0: Adding {compile: {{file-30-.*}} <= file-30.swift} to batch 3
-// SEED0: Forming batch job from 8 constituents
-// SEED0: Forming batch job from 8 constituents
-// SEED0: Forming batch job from 7 constituents
-// SEED0: Forming batch job from 7 constituents
-// SEED0: Adding batch job to task queue: {compile: file-01{{.*}} file-02{{.*}} file-03{{.*}} ... 5 more <= file-01.swift file-02.swift file-03.swift ... 5 more}
-// SEED0: Adding batch job to task queue: {compile: file-09{{.*}} file-10{{.*}} file-11{{.*}} ... 5 more <= file-09.swift file-10.swift file-11.swift ... 5 more}
-// SEED0: Adding batch job to task queue: {compile: file-17{{.*}} file-18{{.*}} file-19{{.*}} ... 4 more <= file-17.swift file-18.swift file-19.swift ... 4 more}
-// SEED0: Adding batch job to task queue: {compile: file-24{{.*}} file-25{{.*}} file-26{{.*}} ... 4 more <= file-24.swift file-25.swift file-26.swift ... 4 more}
-//
-// SEED1: Found 30 batchable jobs
-// SEED1: Forming into 4 batches
-// SEED1: Adding {compile: {{file-01-.*}} <= file-01.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-02-.*}} <= file-02.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-03-.*}} <= file-03.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-04-.*}} <= file-04.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-05-.*}} <= file-05.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-06-.*}} <= file-06.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-07-.*}} <= file-07.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-08-.*}} <= file-08.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-09-.*}} <= file-09.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-10-.*}} <= file-10.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-11-.*}} <= file-11.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-12-.*}} <= file-12.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-13-.*}} <= file-13.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-14-.*}} <= file-14.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-15-.*}} <= file-15.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-16-.*}} <= file-16.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-17-.*}} <= file-17.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-18-.*}} <= file-18.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-19-.*}} <= file-19.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-20-.*}} <= file-20.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-21-.*}} <= file-21.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-22-.*}} <= file-22.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-23-.*}} <= file-23.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-24-.*}} <= file-24.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-25-.*}} <= file-25.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-26-.*}} <= file-26.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-27-.*}} <= file-27.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-28-.*}} <= file-28.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-29-.*}} <= file-29.swift} to batch {{[0-3]}}
-// SEED1: Adding {compile: {{file-30-.*}} <= file-30.swift} to batch {{[0-3]}}
-// SEED1: Forming batch job from 8 constituents
-// SEED1: Forming batch job from 8 constituents
-// SEED1: Forming batch job from 7 constituents
-// SEED1: Forming batch job from 7 constituents
-// SEED1-NOT: Adding batch job to task queue: {compile: file-01{{.*}} file-02{{.*}} file-03{{.*}} ... 5 more <= file-01.swift file-02.swift file-03.swift ... 5 more }
-// SEED1: Added to TaskQueue: {compile: {{.*}} <= {{file-[0-3][2-9].swift .*}}}
-// SEED1: Added to TaskQueue: {compile: {{.*}} <= {{.*}}}
-// SEED1: Added to TaskQueue: {compile: {{.*}} <= {{.*}}}
-//
-// SEED2: Found 30 batchable jobs
-// SEED2: Forming into 4 batches
-// SEED2: Adding {compile: {{file-01-.*}} <= file-01.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-02-.*}} <= file-02.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-03-.*}} <= file-03.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-04-.*}} <= file-04.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-05-.*}} <= file-05.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-06-.*}} <= file-06.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-07-.*}} <= file-07.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-08-.*}} <= file-08.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-09-.*}} <= file-09.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-10-.*}} <= file-10.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-11-.*}} <= file-11.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-12-.*}} <= file-12.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-13-.*}} <= file-13.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-14-.*}} <= file-14.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-15-.*}} <= file-15.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-16-.*}} <= file-16.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-17-.*}} <= file-17.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-18-.*}} <= file-18.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-19-.*}} <= file-19.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-20-.*}} <= file-20.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-21-.*}} <= file-21.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-22-.*}} <= file-22.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-23-.*}} <= file-23.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-24-.*}} <= file-24.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-25-.*}} <= file-25.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-26-.*}} <= file-26.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-27-.*}} <= file-27.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-28-.*}} <= file-28.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-29-.*}} <= file-29.swift} to batch {{[0-3]}}
-// SEED2: Adding {compile: {{file-30-.*}} <= file-30.swift} to batch {{[0-3]}}
-// SEED2: Forming batch job from 8 constituents
-// SEED2: Forming batch job from 8 constituents
-// SEED2: Forming batch job from 7 constituents
-// SEED2: Forming batch job from 7 constituents
-// SEED2-NOT: Adding batch job to task queue: {compile: file-01{{.*}} file-02{{.*}} file-03{{.*}} ... 5 more <= file-01.swift file-02.swift file-03.swift ... 5 more }
-// SEED2: Added to TaskQueue: {compile: {{.*}} <= {{file-[0-3][2-9].swift .*}}}
-// SEED2: Added to TaskQueue: {compile: {{.*}} <= {{.*}}}
-// SEED2: Added to TaskQueue: {compile: {{.*}} <= {{.*}}}
diff --git a/test/Driver/batch_mode_aux_file_order.swift b/test/Driver/batch_mode_aux_file_order.swift
deleted file mode 100644
index 3504bae2840e3..0000000000000
--- a/test/Driver/batch_mode_aux_file_order.swift
+++ /dev/null
@@ -1,20 +0,0 @@
-// When multiple additional-outputs on the same command-line are no longer
-// supported (i.e. when we've moved to mandatory use of output file maps for
-// communicating multiple additional-outputs to frontends) this test will no
-// longer make sense, and should be removed.
-//
-// RUN: %empty-directory(%t)
-// RUN: touch %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/file-04.swift %t/file-05.swift
-// RUN: touch %t/file-06.swift %t/file-07.swift %t/file-08.swift %t/file-09.swift
-//
-// RUN: %swiftc_driver -enable-batch-mode -driver-batch-seed 1 -driver-print-jobs -driver-skip-execution -j 3 -emit-module -module-name foo %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/file-04.swift %t/file-05.swift %t/file-06.swift %t/file-07.swift %t/file-08.swift %t/file-09.swift >%t/out.txt
-// RUN: %FileCheck %s <%t/out.txt
-//
-// Each batch should get 3 primaries; check that each has 3 modules _in the same numeric order_.
-//
-// CHECK: {{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} {{.*}}-primary-file {{[^ ]*[\\/]}}file-[[A1:[0-9]+]].swift{{"?}} {{.*}}-primary-file {{[^ ]*[\\/]}}file-[[A2:[0-9]+]].swift{{"?}} {{.*}}-primary-file {{[^ ]*[\\/]}}file-[[A3:[0-9]+]].swift{{"?}}
-// CHECK-SAME: -o {{.*[\\/]}}file-[[A1]]-{{[a-z0-9]+}}.swiftmodule{{"?}} -o {{.*[\\/]}}file-[[A2]]-{{[a-z0-9]+}}.swiftmodule{{"?}} -o {{.*[\\/]}}file-[[A3]]-{{[a-z0-9]+}}.swiftmodule{{"?}}
-// CHECK: {{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} {{.*}}-primary-file {{[^ ]*[\\/]}}file-[[B1:[0-9]+]].swift{{"?}} {{.*}}-primary-file {{[^ ]*[\\/]}}file-[[B2:[0-9]+]].swift{{"?}} {{.*}}-primary-file {{[^ ]*[\\/]}}file-[[B3:[0-9]+]].swift{{"?}}
-// CHECK-SAME: -o {{.*[\\/]}}file-[[B1]]-{{[a-z0-9]+}}.swiftmodule{{"?}} -o {{.*[\\/]}}file-[[B2]]-{{[a-z0-9]+}}.swiftmodule{{"?}} -o {{.*[\\/]}}file-[[B3]]-{{[a-z0-9]+}}.swiftmodule{{"?}}
-// CHECK: {{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} {{.*}}-primary-file {{[^ ]*[\\/]}}file-[[C1:[0-9]+]].swift{{"?}} {{.*}}-primary-file {{[^ ]*[\\/]}}file-[[C2:[0-9]+]].swift{{"?}} {{.*}}-primary-file {{[^ ]*[\\/]}}file-[[C3:[0-9]+]].swift{{"?}}
-// CHECK-SAME: -o {{.*[\\/]}}file-[[C1]]-{{[a-z0-9]+}}.swiftmodule{{"?}} -o {{.*[\\/]}}file-[[C2]]-{{[a-z0-9]+}}.swiftmodule{{"?}} -o {{.*[\\/]}}file-[[C3]]-{{[a-z0-9]+}}.swiftmodule{{"?}}
diff --git a/test/Driver/batch_mode_bridging_pch.swift b/test/Driver/batch_mode_bridging_pch.swift
deleted file mode 100644
index f55c4eac2c7b8..0000000000000
--- a/test/Driver/batch_mode_bridging_pch.swift
+++ /dev/null
@@ -1,25 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: touch %t/file-01.swift %t/file-02.swift %t/file-03.swift
-// RUN: echo 'public func main() {}' >%t/main.swift
-// RUN: echo 'extern int foo;' >%t/foo-bridging-header.h
-//
-// RUN: %swiftc_driver -enable-bridging-pch -v -import-objc-header %t/foo-bridging-header.h -enable-batch-mode -c -emit-module -module-name main -j 2 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/main.swift %s 2>&1 | %FileCheck %s
-//
-// Next we make a module map with an unknown attribute, which will cause an
-// AST-reader warning while (re)parsing the module map, while attaching a PCH.
-// We turn on serialized diagnostics in the frontends, and check that that
-// warning, issued before the batch-mode multi-file diagnostic multiplexor has
-// its file mappings established, does not crash the multiplexor.
-//
-// RUN: %empty-directory(%t/MyModule)
-// RUN: echo 'module MyModule [DefinitelyNotAnAttribute] { header "header.h" export * }' >%t/MyModule/module.modulemap
-// RUN: touch %t/MyModule/header.h
-// RUN: echo '#include "MyModule/header.h"' >>%t/foo-bridging-header.h
-// RUN: %swiftc_driver -enable-bridging-pch -v -I %t -import-objc-header %t/foo-bridging-header.h -enable-batch-mode -c -emit-module -module-name main -j 2 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/main.swift -serialize-diagnostics %s 2>&1 | %FileCheck %s
-//
-// CHECK: -emit-pch
-// CHECK: -primary-file {{.*}}/file-01.swift{{"?}} -primary-file {{.*}}/file-02.swift{{"?}}
-
-func bar() {
-    print(foo)
-}
diff --git a/test/Driver/batch_mode_parseable_output-fine.swift b/test/Driver/batch_mode_parseable_output-fine.swift
deleted file mode 100644
index e28e6c8756c29..0000000000000
--- a/test/Driver/batch_mode_parseable_output-fine.swift
+++ /dev/null
@@ -1,306 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: touch %t/file-01.swift %t/file-02.swift %t/file-03.swift
-// RUN: echo 'public func main() {}' >%t/main.swift
-//
-// RUN: %swiftc_driver -enable-batch-mode -parseable-output -driver-skip-execution -c -emit-module -module-name main -j 2 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/main.swift 2>&1 | %FileCheck -check-prefix CHECK %s
-//
-//
-// CHECK: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "began",
-// CHECK-NEXT:   "name": "compile",
-// CHECK-NEXT:   "command": "{{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?(\\")?}} -frontend -c -primary-file {{.*}}/file-01.swift{{(\\")?}} {{.*}}file-02.swift{{(\\")?}} {{.*}}file-03.swift{{(\\")?}} {{.*}}main.swift{{(\\")?}} -emit-module-path {{.*}}file-01-[[MODULE01:[a-z0-9]+]].swiftmodule{{(\\")?}} -emit-module-doc-path {{.*}}file-01-[[SWIFTDOC01:[a-z0-9]+]].swiftdoc{{(\\")?}} {{.*}} {{.*}} -module-name main -o {{.*}}file-01-[[OBJ01:[a-z0-9]+]].o{{(\\")?}}",
-// CHECK-NEXT:   "command_executable": "{{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?}}",
-// CHECK-NEXT:   "command_arguments": [
-// CHECK-NEXT:     "-frontend",
-// CHECK-NEXT:     "-c",
-// CHECK-NEXT:     "-primary-file",
-// CHECK-NEXT:     "{{.*[\\/]}}file-01.swift",
-// CHECK-NEXT:     "{{.*[\\/]}}file-02.swift",
-// CHECK-NEXT:     "{{.*[\\/]}}file-03.swift",
-// CHECK-NEXT:     "{{.*[\\/]}}main.swift",
-// CHECK-NEXT:     "-emit-module-path",
-// CHECK-NEXT:     "{{.*[\\/]}}file-01-[[MODULE01:[a-z0-9]+]].swiftmodule",
-// CHECK-NEXT:     "-emit-module-doc-path",
-// CHECK-NEXT:     "{{.*[\\/]}}file-01-[[SWIFTDOC01:[a-z0-9]+]].swiftdoc",
-// CHECK:          "-module-name",
-// CHECK-NEXT:     "main",
-// CHECK-NEXT:     "-o",
-// CHECK-NEXT:     "{{.*[\\/]}}file-01-[[OBJ01:[a-z0-9]+]].o"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "inputs": [
-// CHECK-NEXT:     "{{.*[\\/]}}file-01.swift"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "outputs": [
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "object",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-01-[[OBJ01]].o"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftmodule",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-01-[[MODULE01]].swiftmodule"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftdoc",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-01-[[SWIFTDOC01]].swiftdoc"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftsourceinfo",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-01-[[MODULE01]].swiftsourceinfo"
-// CHECK-NEXT:     }
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "pid": -{{[1-9][0-9]*}},
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   }
-// CHECK-NEXT: }
-// CHECK: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "began",
-// CHECK-NEXT:   "name": "compile",
-// CHECK-NEXT:   "command": "{{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?(\\")?}} -frontend -c {{.*}}file-01.swift{{(\\")?}} -primary-file {{.*}}file-02.swift{{(\\")?}} {{.*}}file-03.swift{{(\\")?}} {{.*}}main.swift{{(\\")?}} -emit-module-path {{.*}}file-02-[[MODULE02:[a-z0-9]+]].swiftmodule{{(\\")?}} -emit-module-doc-path {{.*}}file-02-[[SWIFTDOC02:[a-z0-9]+]].swiftdoc{{(\\")?}} {{.*}} {{.*}} -module-name main -o {{.*}}file-02-[[OBJ02:[a-z0-9]+]].o{{(\\")?}}",
-// CHECK-NEXT:   "command_executable": "{{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?(\\")?}}",
-// CHECK-NEXT:   "command_arguments": [
-// CHECK-NEXT:     "-frontend",
-// CHECK-NEXT:     "-c",
-// CHECK-NEXT:     "{{.*[\\/]}}file-01.swift",
-// CHECK-NEXT:     "-primary-file",
-// CHECK-NEXT:     "{{.*[\\/]}}file-02.swift",
-// CHECK-NEXT:     "{{.*[\\/]}}file-03.swift",
-// CHECK-NEXT:     "{{.*[\\/]}}main.swift",
-// CHECK-NEXT:     "-emit-module-path",
-// CHECK-NEXT:     "{{.*[\\/]}}file-02-[[MODULE02:[a-z0-9]+]].swiftmodule",
-// CHECK-NEXT:     "-emit-module-doc-path",
-// CHECK-NEXT:     "{{.*[\\/]}}file-02-[[SWIFTDOC02:[a-z0-9]+]].swiftdoc",
-// CHECK:          "-module-name",
-// CHECK-NEXT:     "main",
-// CHECK-NEXT:     "-o",
-// CHECK-NEXT:     "{{.*[\\/]}}file-02-[[OBJ02:[a-z0-9]+]].o"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "inputs": [
-// CHECK-NEXT:     "{{.*[\\/]}}file-02.swift"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "outputs": [
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "object",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-02-[[OBJ02]].o"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftmodule",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-02-[[MODULE02]].swiftmodule"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftdoc",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-02-[[SWIFTDOC02]].swiftdoc"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftsourceinfo",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-02-[[MODULE02]].swiftsourceinfo"
-// CHECK-NEXT:     }
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "pid": -{{[1-9][0-9]*}},
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   }
-// CHECK-NEXT: }
-// CHECK: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "began",
-// CHECK-NEXT:   "name": "compile",
-// CHECK-NEXT:   "command": "{{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?(\\")?}} -frontend -c {{.*}}file-01.swift{{(\\")?}} {{.*}}file-02.swift{{(\\")?}} -primary-file {{.*}}file-03.swift{{(\\")?}} {{.*}}main.swift{{(\\")?}} -emit-module-path {{.*}}file-03-[[MODULE03:[a-z0-9]+]].swiftmodule{{(\\")?}} -emit-module-doc-path {{.*}}file-03-[[SWIFTDOC03:[a-z0-9]+]].swiftdoc{{(\\")?}} {{.*}} {{.*}} -module-name main -o {{.*}}file-03-[[OBJ03:[a-z0-9]+]].o{{(\\")?}}",
-// CHECK-NEXT:   "command_executable": "{{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?}}",
-// CHECK-NEXT:   "command_arguments": [
-// CHECK-NEXT:     "-frontend",
-// CHECK-NEXT:     "-c",
-// CHECK-NEXT:     "{{.*}}/file-01.swift",
-// CHECK-NEXT:     "{{.*}}/file-02.swift",
-// CHECK-NEXT:     "-primary-file",
-// CHECK-NEXT:     "{{.*}}/file-03.swift",
-// CHECK-NEXT:     "{{.*}}/main.swift",
-// CHECK-NEXT:     "-emit-module-path",
-// CHECK-NEXT:     "{{.*[\\/]}}file-03-[[MODULE03:[a-z0-9]+]].swiftmodule",
-// CHECK-NEXT:     "-emit-module-doc-path",
-// CHECK-NEXT:     "{{.*[\\/]}}file-03-[[SWIFTDOC03:[a-z0-9]+]].swiftdoc",
-// CHECK:          "-module-name",
-// CHECK-NEXT:     "main",
-// CHECK-NEXT:     "-o",
-// CHECK-NEXT:     "{{.*[\\/]}}file-03-[[OBJ03:[a-z0-9]+]].o"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "inputs": [
-// CHECK-NEXT:     "{{.*[\\/]}}file-03.swift"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "outputs": [
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "object",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-03-[[OBJ03]].o"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftmodule",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-03-[[MODULE03]].swiftmodule"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftdoc",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-03-[[SWIFTDOC03]].swiftdoc"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftsourceinfo",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}file-03-[[MODULE03]].swiftsourceinfo"
-// CHECK-NEXT:     }
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "pid": -{{[1-9][0-9]*}},
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   }
-// CHECK-NEXT: }
-// CHECK: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "began",
-// CHECK-NEXT:   "name": "compile",
-// CHECK-NEXT:   "command": "{{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?(\\")?}} -frontend -c {{.*[\\/]}}file-01.swift{{(\\")?}} {{.*[\\/]}}file-02.swift{{(\\")?}} {{.*[\\/]}}file-03.swift{{(\\")?}} -primary-file {{.*[\\/]}}main.swift{{(\\")?}} -emit-module-path {{.*[\\/]}}main-[[MODULEMAIN:[a-z0-9]+]].swiftmodule{{(\\")?}} -emit-module-doc-path {{.*[\\/]}}main-[[SWIFTDOCMAIN:[a-z0-9]+]].swiftdoc{{(\\")?}} {{.*}} {{.*}} -module-name main -o {{.*[\\/]}}main-[[OBJMAIN:[a-z0-9]+]].o{{(\\")?}}",
-// CHECK-NEXT:   "command_executable": "{{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?}}",
-// CHECK-NEXT:   "command_arguments": [
-// CHECK-NEXT:     "-frontend",
-// CHECK-NEXT:     "-c",
-// CHECK-NEXT:     "{{.*[\\/]}}file-01.swift",
-// CHECK-NEXT:     "{{.*[\\/]}}file-02.swift",
-// CHECK-NEXT:     "{{.*[\\/]}}file-03.swift",
-// CHECK-NEXT:     "-primary-file",
-// CHECK-NEXT:     "{{.*[\\/]}}main.swift",
-// CHECK-NEXT:     "-emit-module-path",
-// CHECK-NEXT:     "{{.*[\\/]}}main-[[MODULEMAIN:[a-z0-9]+]].swiftmodule",
-// CHECK-NEXT:     "-emit-module-doc-path",
-// CHECK-NEXT:     "{{.*[\\/]}}main-[[SWIFTDOCMAIN:[a-z0-9]+]].swiftdoc",
-// CHECK:          "-module-name",
-// CHECK-NEXT:     "main",
-// CHECK-NEXT:     "-o",
-// CHECK-NEXT:     "{{.*[\\/]}}main-[[OBJMAIN:[a-z0-9]+]].o"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "inputs": [
-// CHECK-NEXT:     "{{.*[\\/]}}main.swift"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "outputs": [
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "object",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}main-[[OBJMAIN]].o"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftmodule",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}main-[[MODULEMAIN]].swiftmodule"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftdoc",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}main-[[SWIFTDOCMAIN]].swiftdoc"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftsourceinfo",
-// CHECK-NEXT:       "path": "{{.*[\\/]}}main-[[MODULEMAIN]].swiftsourceinfo"
-// CHECK-NEXT:     }
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "pid": -{{[1-9][0-9]*}},
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   }
-// CHECK-NEXT: }
-// CHECK-NEXT: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "finished",
-// CHECK-NEXT:   "name": "compile",
-// CHECK-NEXT:   "pid": -{{[1-9][0-9]*}},
-// CHECK-NEXT:   "output": "Output placeholder\n",
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   },
-// CHECK-NEXT:   "exit-status": 0
-// CHECK-NEXT: }
-// CHECK-NEXT: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "finished",
-// CHECK-NEXT:   "name": "compile",
-// CHECK-NEXT:   "pid": -{{[1-9][0-9]*}},
-// CHECK-NEXT:   "output": "Output placeholder\n",
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   },
-// CHECK-NEXT:   "exit-status": 0
-// CHECK-NEXT: }
-// CHECK-NEXT: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "finished",
-// CHECK-NEXT:   "name": "compile",
-// CHECK-NEXT:   "pid": -{{[1-9][0-9]*}},
-// CHECK-NEXT:   "output": "Output placeholder\n",
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   },
-// CHECK-NEXT:   "exit-status": 0
-// CHECK-NEXT: }
-// CHECK-NEXT: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "finished",
-// CHECK-NEXT:   "name": "compile",
-// CHECK-NEXT:   "pid": -{{[1-9][0-9]*}},
-// CHECK-NEXT:   "output": "Output placeholder\n",
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   },
-// CHECK-NEXT:   "exit-status": 0
-// CHECK-NEXT: }
-// CHECK-NEXT: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "began",
-// CHECK-NEXT:   "name": "merge-module",
-// CHECK-NEXT:   "command": "{{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?(\\")?}} -frontend -merge-modules -emit-module {{.*[\\/]}}file-01-[[MODULE01]].swiftmodule{{(\\")?}} {{.*[\\/]}}file-02-[[MODULE02]].swiftmodule{{(\\")?}} {{.*[\\/]}}file-03-[[MODULE03]].swiftmodule{{(\\")?}} {{.*[\\/]}}main-[[MODULEMAIN]].swiftmodule{{(\\")?}} {{.*}} -emit-module-doc-path main.swiftdoc -emit-module-source-info-path main.swiftsourceinfo -module-name main -o main.swiftmodule",
-// CHECK-NEXT:   "command_executable": "{{.*[\\/]}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?}}",
-// CHECK-NEXT:   "command_arguments": [
-// CHECK-NEXT:     "-frontend",
-// CHECK-NEXT:     "-merge-modules",
-// CHECK-NEXT:     "-emit-module",
-// CHECK-NEXT:     "{{.*[\\/]}}file-01-[[MODULE01]].swiftmodule",
-// CHECK-NEXT:     "{{.*[\\/]}}file-02-[[MODULE02]].swiftmodule",
-// CHECK-NEXT:     "{{.*[\\/]}}file-03-[[MODULE03]].swiftmodule",
-// CHECK-NEXT:     "{{.*[\\/]}}main-[[MODULEMAIN]].swiftmodule",
-// CHECK:          "-emit-module-doc-path",
-// CHECK-NEXT:     "main.swiftdoc",
-// CHECK:          "-emit-module-source-info-path",
-// CHECK-NEXT:     "main.swiftsourceinfo",
-// CHECK-NEXT:     "-module-name",
-// CHECK-NEXT:     "main",
-// CHECK-NEXT:     "-o",
-// CHECK-NEXT:     "main.swiftmodule"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "inputs": [
-// CHECK-NEXT:     "{{.*[\\/]}}file-01-[[OBJ01]].o",
-// CHECK-NEXT:     "{{.*[\\/]}}file-02-[[OBJ02]].o",
-// CHECK-NEXT:     "{{.*[\\/]}}file-03-[[OBJ03]].o",
-// CHECK-NEXT:     "{{.*[\\/]}}main-[[OBJMAIN]].o"
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "outputs": [
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftmodule",
-// CHECK-NEXT:       "path": "main.swiftmodule"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftdoc",
-// CHECK-NEXT:       "path": "main.swiftdoc"
-// CHECK-NEXT:     },
-// CHECK-NEXT:     {
-// CHECK-NEXT:       "type": "swiftsourceinfo",
-// CHECK-NEXT:       "path": "main.swiftsourceinfo"
-// CHECK-NEXT:     }
-// CHECK-NEXT:   ],
-// CHECK-NEXT:   "pid": {{[1-9][0-9]*}},
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   }
-// CHECK-NEXT: }
-// CHECK-NEXT: {{[1-9][0-9]*}}
-// CHECK-NEXT: {
-// CHECK-NEXT:   "kind": "finished",
-// CHECK-NEXT:   "name": "merge-module",
-// CHECK-NEXT:   "pid": {{[1-9][0-9]*}},
-// CHECK-NEXT:   "output": "Output placeholder\n",
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:     "real_pid": {{[1-9][0-9]*}}
-// CHECK-NEXT:   },
-// CHECK-NEXT:   "exit-status": 0
-// CHECK-NEXT: }
diff --git a/test/Driver/batch_mode_parseable_output_cancellation.swift b/test/Driver/batch_mode_parseable_output_cancellation.swift
deleted file mode 100644
index 206e317fa2069..0000000000000
--- a/test/Driver/batch_mode_parseable_output_cancellation.swift
+++ /dev/null
@@ -1,24 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: touch %t/file-01.swift
-// RUN: echo 'public func main() { help_an_error_happened() }' >%t/main.swift
-//
-// RUN: not %swiftc_driver -enable-batch-mode -parseable-output -serialize-diagnostics -c -emit-module -module-name main -j 1 %t/file-01.swift %t/main.swift 2>&1 | %FileCheck %s -check-prefix CHECK -check-prefix CHECK-%target-os
-//
-//      CHECK:   "kind": "signalled",
-// CHECK-NEXT:   "name": "compile",
-// CHECK-NEXT:   "pid": -{{[1-9][0-9]*}},
-// CHECK-NEXT:   "process": {
-// CHECK-NEXT:   	"real_pid": {{[1-9][0-9]*}}
-//
-// This information is not available on POSIX systems where the child is
-// signalled, but it is available on Windows.  We simply report it there since
-// we already have the information.
-// CHECK-windows-msvc-NEXT:     "usage": {
-// CHECK-windows-msvc-NEXT:       "utime":
-// CHECK-windows-msvc-NEXT:       "stime":
-// CHECK-windows-msvc-NEXT:       "maxrss":
-// CHECK-windows-msvc-NEXT:     }
-//
-// CHECK-NEXT:   },
-// CHECK-NEXT:   "error-message": "{{.*}}",
-// CHECK-NEXT:   "signal": 2
diff --git a/test/Driver/batch_mode_print_jobs.swift b/test/Driver/batch_mode_print_jobs.swift
deleted file mode 100644
index fcf47cbb1e861..0000000000000
--- a/test/Driver/batch_mode_print_jobs.swift
+++ /dev/null
@@ -1,19 +0,0 @@
-// Ensure that the -### and -driver-print-jobs options work properly in batch
-// mode. They should each do the same thing, so test them both.
-//
-// Test be sure that the output does reflect the batching, in other words
-// multiple primary files. Also test to be sure that the output is on
-// stdout, and NOT stderr.
-
-
-// RUN: %empty-directory(%t)
-// RUN: touch %t/file-01.swift %t/file-02.swift %t/file-03.swift
-// RUN: echo 'public func main() {}' >%t/main.swift
-//
-// RUN: %swiftc_driver -enable-batch-mode -c -emit-module -module-name main -j 2 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/main.swift  -driver-print-jobs 2>%t/stderr1 | %FileCheck %s -check-prefix=CHECK-COMBINED
-// RUN: %swiftc_driver -enable-batch-mode -c -emit-module -module-name main -j 2 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/main.swift  -###  2>%t/stderr2 | %FileCheck %s  -check-prefix=CHECK-COMBINED
-// RUN: %FileCheck %s -allow-empty -check-prefix=NEGATIVE-CHECK-COMBINED <%t/stderr1
-// RUN: %FileCheck %s -allow-empty -check-prefix=NEGATIVE-CHECK-COMBINED <%t/stderr2
-//
-// CHECK-COMBINED: -primary-file {{.*(/|\\)}}file-01.swift{{"?}} -primary-file {{.*(/|\\)}}file-02.swift{{"?}} {{.*(/|\\)}}file-03.swift{{"?}} {{.*(/|\\)}}main.swift{{"?}}
-// NEGATIVE-CHECK-COMBINED-NOT: -primary-file {{.*(/|\\)}}file-01.swift{{"?}} -primary-file {{.*(/|\\)}}file-02.swift{{"?}} {{.*(/|\\)}}file-03.swift{{"?}} {{.*(/|\\)}}main.swift{{"?}}
diff --git a/test/Driver/batch_mode_remark.swift b/test/Driver/batch_mode_remark.swift
deleted file mode 100644
index 0402f4c2063e2..0000000000000
--- a/test/Driver/batch_mode_remark.swift
+++ /dev/null
@@ -1,8 +0,0 @@
-// Ensure that driver does not issue a remark iff in batch mode. (The remark has been removed.)
-//
-// RUN: %swiftc_driver -whole-module-optimization -enable-batch-mode   %S/../Inputs/empty.swift -### 2>&1 >/dev/null | %FileCheck %s
-// RUN: %swiftc_driver                                                 %S/../Inputs/empty.swift -### 2>&1 >/dev/null | %FileCheck -allow-empty %s
-// RUN: %swiftc_driver -enable-batch-mode                              %S/../Inputs/empty.swift -### 2>&1 >/dev/null | %FileCheck -allow-empty %s
-// RUN: %swiftc_driver -enable-batch-mode        -disable-batch-mode   %S/../Inputs/empty.swift -### 2>&1 >/dev/null | %FileCheck -allow-empty %s
-//
-// CHECK-NOT: remark: using batch mode
diff --git a/test/Driver/batch_mode_response_files.swift b/test/Driver/batch_mode_response_files.swift
deleted file mode 100644
index 2b3de61aaa306..0000000000000
--- a/test/Driver/batch_mode_response_files.swift
+++ /dev/null
@@ -1,10 +0,0 @@
-// Batch jobs go through a different code path than other jobs, so make sure
-// that they also use response files correctly when their argument lists are
-// too long.
-
-// RUN: %{python} -c 'for i in range(500001): print("-DTEST_" + str(i))' > %t.resp
-// RUN: %swiftc_driver -driver-print-jobs -module-name batch -enable-batch-mode -j 1 -c %S/Inputs/main.swift %S/Inputs/lib.swift @%t.resp 2>&1 > %t.jobs.txt
-// RUN: %FileCheck %s < %t.jobs.txt -check-prefix=BATCH
-
-// BATCH: bin{{/|\\\\}}swift{{c?}}
-// BATCH: @{{[^ ]*}}arguments-{{[0-9a-zA-Z]+}}.resp{{"?}} # -frontend -c -primary-file {{[^ ]+}}/Inputs/main.swift{{"?}} -primary-file {{[^ ]+}}/Inputs/lib.swift
diff --git a/test/Driver/batch_mode_with_WMO_or_index.swift b/test/Driver/batch_mode_with_WMO_or_index.swift
deleted file mode 100644
index 5a8c68f5700cc..0000000000000
--- a/test/Driver/batch_mode_with_WMO_or_index.swift
+++ /dev/null
@@ -1,38 +0,0 @@
-// RUN: %empty-directory(%t)
-//
-// RUN: %swiftc_driver -whole-module-optimization -enable-batch-mode  %S/../Inputs/empty.swift -### 2>%t/stderr_WMO_batch | %FileCheck %s
-// RUN: %swiftc_driver -enable-batch-mode -whole-module-optimization  %S/../Inputs/empty.swift -### 2>%t/stderr_batch_WMO | %FileCheck %s
-// CHECK-NOT: -primary-file
-// RUN: %FileCheck -check-prefix CHECK-WMO %s <%t/stderr_WMO_batch
-// RUN: %FileCheck -check-prefix CHECK-WMO %s <%t/stderr_batch_WMO
-// CHECK-WMO: warning: ignoring '-enable-batch-mode' because '-whole-module-optimization' was also specified
-//
-// RUN: %swiftc_driver -index-file -enable-batch-mode  %S/../Inputs/empty.swift -### 2>%t/stderr_index_batch | %FileCheck %s
-// RUN: %swiftc_driver -enable-batch-mode -index-file  %S/../Inputs/empty.swift -### 2>%t/stderr_batch_index | %FileCheck %s
-// RUN: %FileCheck -check-prefix CHECK-INDEX %s <%t/stderr_index_batch
-// RUN: %FileCheck -check-prefix CHECK-INDEX %s <%t/stderr_batch_index
-// CHECK-INDEX: warning: ignoring '-enable-batch-mode' because '-index-file' was also specified
-//
-// The following test is verifying that -disable-batch-mode overrides an earlier
-// -enable-batch-mode and silences the warning about mixing batch mode with
-// -index-file. Tools that take an existing command line and add -index-file can
-// thus add -disable-batch-mode without having to otherwise interpret the
-// arguments.
-//
-// RUN: %swiftc_driver -disable-batch-mode -index-file  %S/../Inputs/empty.swift -### 2>%t/stderr_nobatch_index | %FileCheck %s
-// RUN: %swiftc_driver -enable-batch-mode -index-file  %S/../Inputs/empty.swift -disable-batch-mode -### 2>%t/stderr_batch_nobatch_index | %FileCheck %s
-// RUN: %FileCheck -allow-empty -check-prefix CHECK-INDEX-DISABLED %s <%t/stderr_nobatch_index
-// RUN: %FileCheck -allow-empty -check-prefix CHECK-INDEX-DISABLED %s <%t/stderr_batch_nobatch_index
-// CHECK-INDEX-DISABLED-NOT: warning
-//
-// This next one is a regression test for a specific failure in the past: wmo +
-// batch mode should not just result in wmo, but also preserve the num-threads
-// argument and (crucially) the resulting fact that the single wmo subprocess
-// generates multiple output files. The build system that invokes swiftc expects
-// multiple outputs.
-//
-// RUN: touch %t/a.swift %t/b.swift %t/c.swift
-// RUN: %swiftc_driver %t/a.swift %t/b.swift %t/c.swift -num-threads 4 -whole-module-optimization -enable-batch-mode -### >%t/stdout_mt_wmo 2>%t/stderr_mt_wmo
-// RUN: %FileCheck --check-prefix CHECK-WMO %s <%t/stderr_mt_wmo
-// RUN: %FileCheck --check-prefix CHECK-MULTITHREADED-WMO-ARGS %s <%t/stdout_mt_wmo
-// CHECK-MULTITHREADED-WMO-ARGS: -num-threads 4 {{.*}}-o {{.*(/|\\)}}a-{{[a-z0-9]+}}.o{{"?}} -o {{.*(/|\\)}}b-{{[a-z0-9]+}}.o{{"?}} -o {{.*(/|\\)}}c-{{[a-z0-9]+}}.o{{"?}}
diff --git a/test/Driver/batch_mode_with_num-threads.swift b/test/Driver/batch_mode_with_num-threads.swift
deleted file mode 100644
index f27aeec15abc8..0000000000000
--- a/test/Driver/batch_mode_with_num-threads.swift
+++ /dev/null
@@ -1,13 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: echo 'print("Hello, World!")' >%t/main.swift
-// RUN: touch %t/bridgingHeader.h
-//
-// Make sure the proper warning is emitted:
-//
-// RUN: %swiftc_driver -enable-batch-mode -num-threads 2 %t/main.swift -import-objc-header %t/bridgingHeader.h -### 2>&1 | %FileCheck %s
-//
-// CHECK: ignoring -num-threads argument; cannot multithread batch mode
-//
-// Make sure that it actually works. (The link step fails if -num-threads is not ignored.)
-//
-// RUN: %swiftc_driver -enable-batch-mode -num-threads 2 -c %t/main.swift -import-objc-header %t/bridgingHeader.h -o %t/main.o
diff --git a/test/Driver/batch_mode_with_pch.swift b/test/Driver/batch_mode_with_pch.swift
deleted file mode 100644
index b787f9f6b11ad..0000000000000
--- a/test/Driver/batch_mode_with_pch.swift
+++ /dev/null
@@ -1,5 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: echo 'print("Hello, World!")' >%t/main.swift
-// RUN: touch %t/bridgingHeader.h
-//
-// RUN: %swiftc_driver -driver-filelist-threshold=0 -enable-batch-mode -num-threads 2 -c %t/main.swift -import-objc-header %t/bridgingHeader.h -o %t/main.o
diff --git a/test/Driver/batch_mode_with_supplementary_filelist.swift b/test/Driver/batch_mode_with_supplementary_filelist.swift
deleted file mode 100644
index 898942b105c99..0000000000000
--- a/test/Driver/batch_mode_with_supplementary_filelist.swift
+++ /dev/null
@@ -1,9 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: echo 'print("Hello, World!")' >%t/main.swift
-// RUN: touch %t/file-01.swift %t/file-02.swift %t/file-03.swift
-//
-// Ensure that the supplementary output filelist argument is passed to the frontend:
-//
-// RUN: %swiftc_driver -enable-batch-mode -driver-filelist-threshold=0 -j2 %t/main.swift %t/file-01.swift %t/file-02.swift %t/file-03.swift -o %t/file-01.o -o %t/file-02.o -o %t/file-03.o -### | %FileCheck %s -check-prefix=CHECK-SUPPLEMENTARY-OUTPUT-FILELIST
-//
-// CHECK-SUPPLEMENTARY-OUTPUT-FILELIST: -supplementary-output-file-map {{.*(/|\\)}}supplementaryOutputs-
diff --git a/test/Driver/batch_mode_with_supplementary_filelist_execution.swift b/test/Driver/batch_mode_with_supplementary_filelist_execution.swift
deleted file mode 100644
index bc082b39108be..0000000000000
--- a/test/Driver/batch_mode_with_supplementary_filelist_execution.swift
+++ /dev/null
@@ -1,12 +0,0 @@
-// REQUIRES: executable_test
-// RUN: %empty-directory(%t)
-// RUN: echo 'print("Hello, World!")' >%t/main.swift
-// RUN: touch %t/𝔼-file-01.swift %t/😂-file-02.swift %t/Ω-file-03.swift
-//
-// Ensure that the supplementary output filelist argument is passed to the frontend.
-// Also use some characters outside the BMP.
-//
-// RUN: %target-build-swift -emit-dependencies -serialize-diagnostics -driver-filelist-threshold=0 -j2 %t/main.swift  %t/𝔼-file-01.swift %t/😂-file-02.swift %t/Ω-file-03.swift -o %t/a.out
-// RUN: %target-codesign %t/a.out
-// RUN: %target-run %t/a.out | %FileCheck %s -check-prefix=CHECK-HELLO-WORLD
-// CHECK-HELLO-WORLD: Hello, World!
diff --git a/test/Driver/batch_mode_with_supplementary_filelist_unicode.swift b/test/Driver/batch_mode_with_supplementary_filelist_unicode.swift
deleted file mode 100644
index 36aa3790b8ebe..0000000000000
--- a/test/Driver/batch_mode_with_supplementary_filelist_unicode.swift
+++ /dev/null
@@ -1,27 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: echo 'print("Hello, World!")' >%t/main.swift
-// RUN: echo "" > %t/𝔼-file-01.swift 
-// RUN: echo "" > %t/😂-file-02.swift 
-// RUN: echo "" > %t/Ω-file-03.swift
-//
-// If the supplementary output file map does not escape the characters in the
-// source files, the frontend won't recognize the desired outputs.
-//
-// RUN: cd %t && %target-build-swift -c -emit-dependencies -serialize-diagnostics -driver-filelist-threshold=0 -j2 main.swift  @%S/Inputs/unicode-filenames.rsp -module-name mod
-//
-// All these files should exist and should successfully be deleted
-// RUN: rm main.d
-// RUN: rm main.dia
-// RUN: rm main.o
-// RUN: rm Ω-file-03.d
-// RUN: rm Ω-file-03.dia
-// RUN: rm Ω-file-03.o
-// RUN: rm Ω-file-03.swift
-// RUN: rm 𝔼-file-01.d
-// RUN: rm 𝔼-file-01.dia
-// RUN: rm 𝔼-file-01.o
-// RUN: rm 𝔼-file-01.swift
-// RUN: rm 😂-file-02.d
-// RUN: rm 😂-file-02.dia
-// RUN: rm 😂-file-02.o
-// RUN: rm 😂-file-02.swift
diff --git a/test/Driver/bridging-pch.swift b/test/Driver/bridging-pch.swift
index 769b22d514bbb..2f50b15d3a36d 100644
--- a/test/Driver/bridging-pch.swift
+++ b/test/Driver/bridging-pch.swift
@@ -6,68 +6,63 @@
 // YESPCHACT: 2: input, "{{.*}}bridging-pch.swift", swift
 // YESPCHACT: 3: compile, {2, 1}, none
 
-// RUN: %target-build-swift -typecheck -disable-bridging-pch -driver-print-actions -import-objc-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=NOPCHACT
+// RUN: %target-build-swift -typecheck -disable-bridging-pch -driver-print-actions -import-bridging-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=NOPCHACT
 // NOPCHACT: 0: input, "{{.*}}bridging-pch.swift", swift
 // NOPCHACT: 1: compile, {0}, none
 
-// RUN: %target-build-swift -typecheck -driver-print-jobs -import-objc-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=YESPCHJOB
+// RUN: %target-build-swift -typecheck -driver-print-jobs -import-bridging-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=YESPCHJOB
 // YESPCHJOB: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -emit-pch -o {{.*}}bridging-header-{{.*}}.pch
-// YESPCHJOB: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -import-objc-header {{.*}}bridging-header-{{.*}}.pch
+// YESPCHJOB: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -import-bridging-header {{.*}}bridging-header-{{.*}}.pch
 
-// RUN: %target-build-swift -typecheck -disable-bridging-pch  -driver-print-jobs -import-objc-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=NOPCHJOB
-// NOPCHJOB: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -import-objc-header {{.*}}Inputs/bridging-header.h
+// RUN: %target-build-swift -typecheck -disable-bridging-pch  -driver-print-jobs -import-bridging-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=NOPCHJOB
+// NOPCHJOB: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -import-bridging-header {{.*}}Inputs/bridging-header.h
 
-// RUN: %target-build-swift -typecheck -driver-print-jobs -index-store-path %t/idx -import-objc-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=INDEXSTORE
+// RUN: %target-build-swift -typecheck -driver-print-jobs -index-store-path %t/idx -import-bridging-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=INDEXSTORE
 // INDEXSTORE: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -index-store-path {{.*}}/idx{{"?}} -emit-pch -o {{.*}}bridging-header-{{.*}}.pch
 
 // RUN: echo "{\"\": {\"swift-dependencies\": \"%/t/master.swiftdeps\"}, \"%/s\": {\"swift-dependencies\": \"%/t/bridging-header.swiftdeps\"}}" > %t.json
-// RUN: %target-build-swift -typecheck -incremental -enable-bridging-pch -output-file-map %t.json -import-objc-header %S/Inputs/bridging-header.h %s
+// RUN: %target-build-swift -typecheck -incremental -enable-bridging-pch -output-file-map %t.json -import-bridging-header %S/Inputs/bridging-header.h %s
 
 // RUN: mkdir %t/tmp
-// RUN: env TMP="%t/tmp/" TMPDIR="%t/tmp/" not %target-build-swift -typecheck -import-objc-header %S/../Inputs/empty.h -driver-use-frontend-path "%{python.unquoted};%S/Inputs/crash-after-generating-pch.py" -v %s
+// RUN: env TMP="%t/tmp/" TMPDIR="%t/tmp/" not %target-build-swift -typecheck -import-bridging-header %S/../Inputs/empty.h -driver-use-frontend-path "%{python.unquoted};%S/Inputs/crash-after-generating-pch.py" -v %s
 // RUN: ls %/t/tmp/ | grep .*pch
 
 // Test persistent PCH
 
-// RUN: %target-build-swift -typecheck -driver-print-actions -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHACT
+// RUN: %target-build-swift -typecheck -driver-print-actions -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHACT
 // PERSISTENT-YESPCHACT: 0: input, "{{.*}}Inputs/bridging-header.h", clang-header
 // PERSISTENT-YESPCHACT: 1: generate-pch, {0}, none
 // PERSISTENT-YESPCHACT: 2: input, "{{.*}}bridging-pch.swift", swift
 // PERSISTENT-YESPCHACT: 3: compile, {2, 1}, none
 
-// RUN: %target-build-swift -c -driver-print-actions -embed-bitcode -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHACTBC
+// RUN: %target-build-swift -c -driver-print-actions -embed-bitcode -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHACTBC
 // PERSISTENT-YESPCHACTBC: 0: input, "{{.*}}Inputs/bridging-header.h", clang-header
 // PERSISTENT-YESPCHACTBC: 1: generate-pch, {0}, none
 // PERSISTENT-YESPCHACTBC: 2: input, "{{.*}}bridging-pch.swift", swift
 // PERSISTENT-YESPCHACTBC: 3: compile, {2, 1}, llvm-bc
 
-// RUN: %target-build-swift -typecheck -disable-bridging-pch -driver-print-actions -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s 2>&1 | %FileCheck %s -check-prefix=NOPCHACT
+// RUN: %target-build-swift -typecheck -disable-bridging-pch -driver-print-actions -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s 2>&1 | %FileCheck %s -check-prefix=NOPCHACT
 
-// RUN: %target-build-swift -typecheck -driver-print-jobs -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -disable-bridging-pch %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-DISABLED-YESPCHJOB
-// RUN: %target-build-swift -typecheck -driver-print-jobs -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -whole-module-optimization -disable-bridging-pch %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-DISABLED-YESPCHJOB
+// RUN: %target-build-swift -typecheck -driver-print-jobs -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -disable-bridging-pch %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-DISABLED-YESPCHJOB
+// RUN: %target-build-swift -typecheck -driver-print-jobs -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -whole-module-optimization -disable-bridging-pch %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-DISABLED-YESPCHJOB
 // PERSISTENT-DISABLED-YESPCHJOB-NOT: -pch-output-dir
 
-// RUN: %target-build-swift -typecheck -driver-print-jobs -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHJOB
-// RUN: %target-build-swift -typecheck -driver-print-jobs -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s %S/Inputs/error.swift -driver-batch-count 2 -enable-batch-mode 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHJOB
-// PERSISTENT-YESPCHJOB: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -emit-pch -pch-output-dir {{.*}}/pch
-// PERSISTENT-YESPCHJOB: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -import-objc-header {{.*}}bridging-header.h{{"?}} -pch-output-dir {{.*}}/pch{{"?}} -pch-disable-validation
-
-// RUN: %target-build-swift -typecheck -driver-print-jobs -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -serialize-diagnostics %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHJOB-DIAG1
+// RUN: %target-build-swift -typecheck -driver-print-jobs -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -serialize-diagnostics %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHJOB-DIAG1
 // PERSISTENT-YESPCHJOB-DIAG1: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -serialize-diagnostics-path {{.*}}bridging-header-{{.*}}.dia{{"?}} {{.*}} -emit-pch -pch-output-dir {{.*}}/pch
 
-// RUN: %target-build-swift -typecheck -driver-print-jobs -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch-out-dir -serialize-diagnostics %s -emit-module -emit-module-path /module-path-dir 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHJOB-DIAG2
+// RUN: %target-build-swift -typecheck -driver-print-jobs -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch-out-dir -serialize-diagnostics %s -emit-module -emit-module-path /module-path-dir 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-YESPCHJOB-DIAG2
 // PERSISTENT-YESPCHJOB-DIAG2: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -serialize-diagnostics-path {{.*}}/pch-out-dir{{/|\\\\}}bridging-header-{{.*}}.dia{{"?}} {{.*}} -emit-pch -pch-output-dir {{.*}}/pch-out-dir
 
-// RUN: %target-build-swift -typecheck -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -parseable-output -driver-skip-execution %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-OUTPUT
+// RUN: %target-build-swift -typecheck -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -parseable-output -driver-skip-execution %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-OUTPUT
 // PERSISTENT-OUTPUT-NOT: "outputs": [
 
-// RUN: %target-build-swift -typecheck -driver-print-jobs -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -whole-module-optimization %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-WMO-YESPCHJOB --implicit-check-not pch-disable-validation
-// PERSISTENT-WMO-YESPCHJOB: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -import-objc-header {{.*}}bridging-header.h{{"?}} -pch-output-dir {{.*}}/pch
+// RUN: %target-build-swift -typecheck -driver-print-jobs -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch -whole-module-optimization %s 2>&1 | %FileCheck %s -check-prefix=PERSISTENT-WMO-YESPCHJOB --implicit-check-not pch-disable-validation
+// PERSISTENT-WMO-YESPCHJOB: {{.*}}swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend {{.*}} -import-bridging-header {{.*}}bridging-header.h{{"?}} -pch-output-dir {{.*}}/pch
 
-// RUN: %target-build-swift -typecheck -disable-bridging-pch  -driver-print-jobs -import-objc-header %/S/Inputs/bridging-header.h -pch-output-dir %t/pch %/s 2>&1 | %FileCheck %s -check-prefix=NOPCHJOB
-// RUN: %target-build-swift -typecheck -incremental -enable-bridging-pch -output-file-map %t.json -import-objc-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s
+// RUN: %target-build-swift -typecheck -disable-bridging-pch  -driver-print-jobs -import-bridging-header %/S/Inputs/bridging-header.h -pch-output-dir %t/pch %/s 2>&1 | %FileCheck %s -check-prefix=NOPCHJOB
+// RUN: %target-build-swift -typecheck -incremental -enable-bridging-pch -output-file-map %t.json -import-bridging-header %S/Inputs/bridging-header.h -pch-output-dir %t/pch %s
 
-// RUN: %target-build-swift -### -typecheck -O -import-objc-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=OPTPCH
+// RUN: %target-build-swift -### -typecheck -O -import-bridging-header %S/Inputs/bridging-header.h %s 2>&1 | %FileCheck %s -check-prefix=OPTPCH
 // OPTPCH: swift{{(c|c-legacy-driver|-frontend)?(\.exe)?"?}} -frontend
 // OPTPCH-SAME: -O{{ }}
 // OPTPCH-SAME: -emit-pch
diff --git a/test/Driver/color-diagnostics.swift b/test/Driver/color-diagnostics.swift
index 6e2b2893899fe..df67d2a6cbc5a 100644
--- a/test/Driver/color-diagnostics.swift
+++ b/test/Driver/color-diagnostics.swift
@@ -1,9 +1,6 @@
-// RUN: not %target-swiftc_driver -color-diagnostics -diagnostic-style=llvm -emit-executable -o %t %s 2>&1 \
-// RUN:     | %FileCheck -check-prefix=CHECK-CD %s
-// CHECK-CD: [0m1 = 2{{$}}
+// RUN: %empty-directory(%t)
+// RUN: not %target-swiftc_driver -color-diagnostics -diagnostic-style=llvm -emit-executable -o %t/out %s
+
 
-// RUN: not %target-swiftc_driver -no-color-diagnostics -emit-executable -o %t %s 2>&1 \
-// RUN:     | %FileCheck -check-prefix=CHECK-NCD %s
-// CHECK-NCD: {{[ ]}}1 = 2
 
 1 = 2
diff --git a/test/Driver/continue-building-after-errors.swift b/test/Driver/continue-building-after-errors.swift
index 4744e14ee7562..853b361d5af84 100644
--- a/test/Driver/continue-building-after-errors.swift
+++ b/test/Driver/continue-building-after-errors.swift
@@ -1,10 +1,6 @@
 // RUN: not %target-build-swift %S/Inputs/error.swift %s 2>&1 | %FileCheck %s
 // RUN: not %target-build-swift -continue-building-after-errors %S/Inputs/error.swift %s 2>&1 | %FileCheck -check-prefix=CHECK-CONTINUE %s
 
-// Check that batch mode implies -continue-building-after-errors.
-// RUN: touch %t.empty.swift
-// RUN: not %target-build-swift -enable-batch-mode -j2 %S/Inputs/error.swift %S/../Inputs/empty.swift %s %t.empty.swift 2>&1 | %FileCheck -check-prefix=CHECK-BATCH %s
-
 // CHECK: self.bar = self.bar
 // CHECK-NOT: self.baz = self.baz
 // CHECK-CONTINUE: self.bar = self.bar
diff --git a/test/Driver/createCompilerInvocation.swift b/test/Driver/createCompilerInvocation.swift
index 1f9bec4fe9c3a..12ae602b01107 100644
--- a/test/Driver/createCompilerInvocation.swift
+++ b/test/Driver/createCompilerInvocation.swift
@@ -9,12 +9,13 @@
 // CHECK-NOWARN-NOT: warning
 
 // RUN: %swift-ide-test_plain -test-createCompilerInvocation \
-// RUN:   -module-name foo -emit-module -emit-module-path %t/foo.swiftmodule -emit-objc-header -emit-objc-header-path %t/foo.h -enable-library-evolution -emit-module-interface -emit-module-interface-path %t/foo.swiftinterface -emit-library -emit-tbd -emit-tbd-path %t/foo.tbd -emit-dependencies -serialize-diagnostics %s \
+// RUN:   -swift-version 5 -module-name foo -emit-module -emit-module-path %t/foo.swiftmodule -emit-objc-header -emit-objc-header-path %t/foo.h -enable-library-evolution -emit-module-interface -emit-module-interface-path %t/foo.swiftinterface -emit-library -emit-tbd -emit-tbd-path %t/foo.tbd -emit-dependencies -serialize-diagnostics %s \
 // RUN:   2>&1 | %FileCheck %s --check-prefix=NORMAL_ARGS --implicit-check-not="error: "
 // NORMAL_ARGS: Frontend Arguments BEGIN
 // NORMAL_ARGS-DAG: -o{{$}}
 // NORMAL_ARGS-DAG: foo-{{[a-z0-9]+}}.o
 // NORMAL_ARGS-DAG: -c{{$}}
+// NORMAL_ARGS-DAG: -swift-version
 // NORMAL_ARGS-DAG: -module-name
 // NORMAL_ARGS-DAG: -emit-module-path
 // NORMAL_ARGS-DAG: -emit-module-doc-path
@@ -26,7 +27,7 @@
 // NORMAL_ARGS: Frontend Arguments END
 
 // RUN: %swift-ide-test_plain -test-createCompilerInvocation -force-no-outputs \
-// RUN:   -module-name foo -emit-module -emit-module-path %t/foo.swiftmodule -emit-objc-header -emit-objc-header-path %t/foo.h -enable-library-evolution -emit-module-interface -emit-module-interface-path %t/foo.swiftinterface -emit-library -emit-tbd -emit-tbd-path %t/foo.tbd -emit-dependencies -serialize-diagnostics %s \
+// RUN:   -swift-version 5 -module-name foo -emit-module -emit-module-path %t/foo.swiftmodule -emit-objc-header -emit-objc-header-path %t/foo.h -enable-library-evolution -emit-module-interface -emit-module-interface-path %t/foo.swiftinterface -emit-library -emit-tbd -emit-tbd-path %t/foo.tbd -emit-dependencies -serialize-diagnostics %s \
 // RUN:   2>&1 > %t.nooutput_args
 // RUN: %FileCheck %s --check-prefix=NOOUTPUT_ARGS --implicit-check-not="error: " < %t.nooutput_args
 // RUN: %FileCheck %s --check-prefix=NOOUTPUT_ARGS_NEG --implicit-check-not="error: " < %t.nooutput_args
@@ -40,3 +41,10 @@
 // NOOUTPUT_ARGS-DAG: -typecheck
 // NOOUTPUT_ARGS-DAG: -module-name
 // NOOUTPUT_ARGS: Frontend Arguments END
+
+// Make sure that '-incremental' is ignored, we don't want SourceKit to run with
+// reference dependency tracking enabled. The legacy driver simply doesn't
+// implement incremental compilation, but make sure when we switch to the new
+// driver this doesn't start failing.
+// RUN: %swift-ide-test_plain -test-createCompilerInvocation -incremental %S/Input/main.swift | %FileCheck --check-prefix INCREMENTAL %s
+// INCREMENTAL-NOT: emit-reference-dependencies
diff --git a/test/Driver/filelists.swift b/test/Driver/filelists.swift
index a95edaf2b30fc..4152a18e42c1d 100644
--- a/test/Driver/filelists.swift
+++ b/test/Driver/filelists.swift
@@ -1,3 +1,7 @@
+// This test is flaky on FreeBSD. The compiler is occasionally killed.
+// rdar://159456203
+// UNSUPPORTED: OS=freebsd
+
 // UNSUPPORTED: OS=windows-msvc
 // RUN: %empty-directory(%t)
 // RUN: touch %t/a.swift %t/b.swift %t/c.swift
diff --git a/test/Driver/force-response-files.swift b/test/Driver/force-response-files.swift
index 0e2a4c1760f1a..2b97797499bce 100644
--- a/test/Driver/force-response-files.swift
+++ b/test/Driver/force-response-files.swift
@@ -4,7 +4,3 @@
 // RUN: %swiftc_driver -driver-force-response-files -typecheck %S/../Inputs/empty.swift -### 2>&1 | %FileCheck %s
 // CHECK: @
 // CHECK: .resp
-
-// RUN: %swiftc_driver -enable-batch-mode -driver-force-response-files -typecheck %S/../Inputs/empty.swift -### 2>&1 | %FileCheck %s -check-prefix=BATCH
-// BATCH: @
-// BATCH: .resp
diff --git a/test/Driver/linker-rpath.swift b/test/Driver/linker-rpath.swift
index 72f76202320d9..fbf0d9e427f30 100644
--- a/test/Driver/linker-rpath.swift
+++ b/test/Driver/linker-rpath.swift
@@ -8,32 +8,37 @@
 // RUN: %swiftc_driver_plain -driver-print-jobs -target x86_64-apple-macosx10.14.4 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target x86_64-apple-macosx10.15 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target x86_64-apple-macosx11.0 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
-// RUN: %swiftc_driver_plain -driver-print-jobs -target x86_64-apple-macosx12.0 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target x86_64-apple-macosx12.0 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target x86_64-apple-macosx26.0 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
 
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios12 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios12.1 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios12.2 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios13 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios14 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
-// RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios15 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios15 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios26 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
 
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios13.1-macabi %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios14-macabi %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
-// RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios15-macabi %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios15-macabi %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-ios26-macabi %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
 
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-tvos12 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-tvos12.1 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-tvos12.2 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-tvos13 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-tvos14 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
-// RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-tvos15 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-tvos15 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target arm64-apple-tvos26 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
 
 // RUN: %swiftc_driver_plain -driver-print-jobs -target armv7k-apple-watchos5 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target armv7k-apple-watchos5.1 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target armv7k-apple-watchos5.2 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target armv7k-apple-watchos6 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
 // RUN: %swiftc_driver_plain -driver-print-jobs -target armv7k-apple-watchos7 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
-// RUN: %swiftc_driver_plain -driver-print-jobs -target armv7k-apple-watchos8 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target armv7k-apple-watchos8 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -target armv7k-apple-watchos26 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
 
 // RPATH: bin/ld{{"? }}
 // RPATH-SAME: -rpath {{"?/usr/lib/swift(-.+)?"? }}
@@ -51,7 +56,7 @@
 
 // ### Test with -no-toolchain-stdlib-rpath
 // RUN: %swiftc_driver_plain -driver-print-jobs -no-toolchain-stdlib-rpath -target x86_64-apple-macosx10.9 %S/../Inputs/empty.swift | %FileCheck -check-prefix RPATH %s
-// RUN: %swiftc_driver_plain -driver-print-jobs -no-toolchain-stdlib-rpath -target x86_64-apple-macosx12.0 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
+// RUN: %swiftc_driver_plain -driver-print-jobs -no-toolchain-stdlib-rpath -target x86_64-apple-macosx26.0 %S/../Inputs/empty.swift | %FileCheck -check-prefix NO-RPATH %s
 
 // TOOLCHAIN-RPATH: bin/ld{{"? }}
 // TOOLCHAIN-RPATH-SAME: -rpath garbage/[[PLATFORM]]{{ }}
diff --git a/test/Driver/linker.swift b/test/Driver/linker.swift
index 751d4d8c527c5..201c0a5bf4abd 100644
--- a/test/Driver/linker.swift
+++ b/test/Driver/linker.swift
@@ -344,7 +344,6 @@
 
 // LINUX_DYNLIB-x86_64: clang{{(\.exe)?"? }}
 // LINUX_DYNLIB-x86_64-DAG: -shared
-// LINUX_DYNLIB-x86_64-DAG: -fuse-ld=gold
 // LINUX_DYNLIB-x86_64-NOT: -pie
 // LINUX_DYNLIB-x86_64-DAG: -Xlinker -rpath -Xlinker [[STDLIB_PATH:[^ ]+(/|\\\\)lib(/|\\\\)swift(/|\\\\)linux]]
 // LINUX_DYNLIB-x86_64: [[STDLIB_PATH]]{{/|\\\\}}x86_64{{/|\\\\}}swiftrt.o
diff --git a/test/Driver/loaded_module_trace.swift b/test/Driver/loaded_module_trace.swift
index d38d90a09c82d..b3fd4fd5f2b53 100644
--- a/test/Driver/loaded_module_trace.swift
+++ b/test/Driver/loaded_module_trace.swift
@@ -12,6 +12,7 @@
 // CHECK: "version":2
 // CHECK: "name":"loaded_module_trace"
 // CHECK: "arch":"{{[^"]*}}"
+// CHECK: "languageMode":"4"
 // CHECK: "strictMemorySafety":false
 // CHECK: "swiftmodules":[
 // CHECK-DAG: "{{[^"]*\\[/\\]}}Module2.swiftmodule"
diff --git a/test/Driver/loaded_module_trace_enabled_features.swift b/test/Driver/loaded_module_trace_enabled_features.swift
new file mode 100644
index 0000000000000..58554936564e4
--- /dev/null
+++ b/test/Driver/loaded_module_trace_enabled_features.swift
@@ -0,0 +1,83 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend %s -emit-module -o /dev/null -swift-version 4 \
+// RUN:   -emit-loaded-module-trace-path %t/swift4.trace.json
+// RUN: %FileCheck -check-prefix=CHECK-SWIFT4 %s < %t/swift4.trace.json
+
+// RUN: %target-swift-frontend %s -emit-module -o /dev/null -swift-version 5 \
+// RUN:   -emit-loaded-module-trace-path %t/swift5.trace.json
+// RUN: %FileCheck -check-prefix=CHECK-SWIFT5 %s < %t/swift5.trace.json
+
+// RUN: %target-swift-frontend %s -emit-module -o /dev/null -swift-version 5 \
+// RUN:   -emit-loaded-module-trace-path %t/swift5_and_features.trace.json \
+// RUN:   -enable-experimental-feature ParserValidation \
+// RUN:   -enable-upcoming-feature RegionBasedIsolation \
+// RUN:   -strict-memory-safety
+// RUN: %FileCheck -check-prefix=CHECK-SWIFT5-PLUS %s < %t/swift5_and_features.trace.json
+
+// RUN: %target-swift-frontend %s -emit-module -o /dev/null -swift-version 6 \
+// RUN:   -emit-loaded-module-trace-path %t/swift6.trace.json
+// RUN: %FileCheck -check-prefix=CHECK-SWIFT6 %s < %t/swift6.trace.json
+
+// NOTE: The matching of the enabledLanguageFeatures lists below is
+// intentionally inexact. There are few experimental features (ParserRoundTrip,
+// ParserValidation) that are enabled by default in asserts compilers but
+// otherwise disabled, so the enabled feature lists will sometimes contain
+// additional entries.
+
+// REQUIRES: swift_feature_ParserValidation
+// REQUIRES: swift_feature_RegionBasedIsolation
+
+// CHECK-SWIFT4: {
+// CHECK-SWIFT4: "version":2
+// CHECK-SWIFT4: "arch":"{{[^"]*}}"
+// CHECK-SWIFT4: "languageMode":"4"
+// CHECK-SWIFT4: "enabledLanguageFeatures":[
+// CHECK-SWIFT4: ]
+// CHECK-SWIFT4: "strictMemorySafety":false
+
+// CHECK-SWIFT5: {
+// CHECK-SWIFT5: "version":2
+// CHECK-SWIFT5: "arch":"{{[^"]*}}"
+// CHECK-SWIFT5: "languageMode":"5"
+// CHECK-SWIFT5: "enabledLanguageFeatures":[
+// CHECK-SWIFT5: "NonfrozenEnumExhaustivity"
+// CHECK-SWIFT5: ]
+// CHECK-SWIFT5: "strictMemorySafety":false
+
+// CHECK-SWIFT5-PLUS: {
+// CHECK-SWIFT5-PLUS: "version":2
+// CHECK-SWIFT5-PLUS: "arch":"{{[^"]*}}"
+// CHECK-SWIFT5-PLUS: "languageMode":"5"
+// CHECK-SWIFT5-PLUS: "enabledLanguageFeatures":[
+// CHECK-SWIFT5-PLUS: "NonfrozenEnumExhaustivity",
+// CHECK-SWIFT5-PLUS: "ParserValidation",
+// CHECK-SWIFT5-PLUS: "RegionBasedIsolation",
+// CHECK-SWIFT5-PLUS: "StrictMemorySafety"
+// CHECK-SWIFT5-PLUS: ]
+// CHECK-SWIFT5-PLUS: "strictMemorySafety":true
+
+// CHECK-SWIFT6: {
+// CHECK-SWIFT6: "version":2
+// CHECK-SWIFT6: "arch":"{{[^"]*}}"
+// CHECK-SWIFT6: "languageMode":"6"
+// CHECK-SWIFT6: "enabledLanguageFeatures":[
+// CHECK-SWIFT6: "BareSlashRegexLiterals",
+// CHECK-SWIFT6: "ConciseMagicFile",
+// CHECK-SWIFT6: "DeprecateApplicationMain",
+// CHECK-SWIFT6: "DisableOutwardActorInference",
+// CHECK-SWIFT6: "DynamicActorIsolation",
+// CHECK-SWIFT6: "ForwardTrailingClosures",
+// CHECK-SWIFT6: "GlobalActorIsolatedTypesUsability",
+// CHECK-SWIFT6: "GlobalConcurrency",
+// CHECK-SWIFT6: "ImplicitOpenExistentials",
+// CHECK-SWIFT6: "ImportObjcForwardDeclarations",
+// CHECK-SWIFT6: "InferSendableFromCaptures",
+// CHECK-SWIFT6: "IsolatedDefaultValues",
+// CHECK-SWIFT6: "NonfrozenEnumExhaustivity",
+// CHECK-SWIFT6: "RegionBasedIsolation",
+// CHECK-SWIFT6: "StrictConcurrency"
+// CHECK-SWIFT6: ]
+// CHECK-SWIFT6: "strictMemorySafety":false
+
+import Swift
diff --git a/test/Driver/loaded_module_trace_multifile.swift b/test/Driver/loaded_module_trace_multifile.swift
index 9c5fb94e56306..36f947ff8f726 100644
--- a/test/Driver/loaded_module_trace_multifile.swift
+++ b/test/Driver/loaded_module_trace_multifile.swift
@@ -14,6 +14,9 @@
 // CHECK: "version":2
 // CHECK: "name":"loaded_module_trace_multifile"
 // CHECK: "arch":"{{[^"]*}}"
+// CHECK: "languageMode":"4"
+// CHECK: "enabledLanguageFeatures":[
+// CHECK: ]
 // CHECK: "swiftmodules":[
 // CHECK-DAG: "{{[^"]*\\[/\\]}}Module2.swiftmodule"
 // CHECK-DAG: "{{[^"]*\\[/\\]}}Swift.swiftmodule{{(\\[/\\][^"]+[.]swiftmodule)?}}"
diff --git a/test/Driver/macabi-environment.swift b/test/Driver/macabi-environment.swift
index a55b43104be88..8dde8c5bb170a 100644
--- a/test/Driver/macabi-environment.swift
+++ b/test/Driver/macabi-environment.swift
@@ -54,7 +54,7 @@
 // RUN: %swiftc_driver -sdk "" -sdk "" -driver-print-jobs -target x86_64-apple-macosx10.14 -target-variant x86_64-apple-ios13.1-macabi -enable-bridging-pch -import-objc-header %S/Inputs/bridging-header.h %s | %FileCheck -check-prefix=ZIPPERED-VARIANT-PCH %s
 // ZIPPERED-VARIANT-PCH: bin/swift
 // ZIPPERED-VARIANT-PCH: -target x86_64-apple-macosx10.14 -target-variant x86_64-apple-ios13.1-macabi
-// ZIPPERED_VARIANT-PCH  -emit-pch
+// ZIPPERED_VARIANT-PCH:  -emit-pch
 // ZIPPERED-VARIANT-PCH: bin/swift
 // ZIPPERED-VARIANT-PCH: -target x86_64-apple-macosx10.14 -target-variant x86_64-apple-ios13.1-macabi
 // ZIPPERED-VARIANT-PCH: bin/ld
@@ -78,7 +78,7 @@
 // RUN: %swiftc_driver -sdk "" -sdk "" -driver-print-jobs -target x86_64-apple-ios13.1-macabi -target-variant x86_64-apple-macosx10.14 -enable-bridging-pch -import-objc-header %S/Inputs/bridging-header.h %s | %FileCheck -check-prefix=REVERSE-ZIPPERED-VARIANT-PCH %s
 // REVERSE-ZIPPERED-VARIANT-PCH: bin/swift
 // REVERSE-ZIPPERED-VARIANT-PCH: -target x86_64-apple-ios13.1-macabi -target-variant x86_64-apple-macosx10.14
-// REVERSE-ZIPPERED_VARIANT-PCH  -emit-pch
+// REVERSE-ZIPPERED_VARIANT-PCH:  -emit-pch
 // REVERSE-ZIPPERED-VARIANT-PCH: bin/swift
 // REVERSE-ZIPPERED-VARIANT-PCH: -target x86_64-apple-ios13.1-macabi -target-variant x86_64-apple-macosx10.14
 // REVERSE-ZIPPERED-VARIANT-PCH: bin/ld
diff --git a/test/Driver/negating_WMO.swift b/test/Driver/negating_WMO.swift
index 6fc30ae91c893..85a6cef7a6f0f 100644
--- a/test/Driver/negating_WMO.swift
+++ b/test/Driver/negating_WMO.swift
@@ -4,7 +4,3 @@
 // WMO-NOT: -primary-file
 // RUN: %swiftc_driver -whole-module-optimization -no-whole-module-optimization %S/../Inputs/empty.swift -### 2>&1 | %FileCheck -check-prefix NO-WMO %s
 // NO-WMO: -primary-file
-
-// RUN: %swiftc_driver -enable-batch-mode -whole-module-optimization -no-whole-module-optimization %S/../Inputs/empty.swift -### 2>&1 | %FileCheck -check-prefix BATCH %s
-// BATCH: -primary-file
-// BATCH-NOT: warning: ignoring '-enable-batch-mode' because '-whole-module-optimization' was also specified
diff --git a/test/Driver/opt-record.swift b/test/Driver/opt-record.swift
index 5d12e7ac8cfc5..ceaa104b1f0d9 100644
--- a/test/Driver/opt-record.swift
+++ b/test/Driver/opt-record.swift
@@ -27,7 +27,7 @@ public func bar() {
   // YAML:        File:            {{.*}}opt-record.swift
   // YAML:        Line:            [[@LINE-6]]
   // YAML:        Column:          3
-  // YAML-NEXT: Function:        'bar()'
+  // YAML-NEXT: Function:        '$s12optrecordmod3baryyF'
   // YAML-NEXT: Args:
   // YAML-NEXT:   - Callee:          '"optrecordmod.foo()"'
   // YAML-NEXT:     DebugLoc:
diff --git a/test/Driver/print_target_info.swift b/test/Driver/print_target_info.swift
index b31a3ed582fd8..cce06777c7170 100644
--- a/test/Driver/print_target_info.swift
+++ b/test/Driver/print_target_info.swift
@@ -11,8 +11,8 @@
 // RUN: %swift_driver -print-target-info -target x86_64-apple-macosx10.15 -target-variant x86_64-apple-ios13.1-macabi | %FileCheck -check-prefix CHECK-PRE-CONCURRENCY-ZIPPERED %s
 // RUN: %target-swift-frontend -print-target-info -target x86_64-apple-macosx10.15 -target-variant x86_64-apple-ios13.1-macabi | %FileCheck -check-prefix CHECK-PRE-CONCURRENCY-ZIPPERED %s
 
-// RUN: %swift_driver -print-target-info -target x86_64-apple-macosx12.0 -target-variant x86_64-apple-ios15-macabi | %FileCheck -check-prefix CHECK-ZIPPERED %s
-// RUN: %target-swift-frontend -print-target-info -target x86_64-apple-macosx12.0 -target-variant x86_64-apple-ios15-macabi | %FileCheck -check-prefix CHECK-ZIPPERED %s
+// RUN: %swift_driver -print-target-info -target x86_64-apple-macosx26.0 -target-variant x86_64-apple-ios26-macabi | %FileCheck -check-prefix CHECK-ZIPPERED %s
+// RUN: %target-swift-frontend -print-target-info -target x86_64-apple-macosx26.0 -target-variant x86_64-apple-ios26-macabi | %FileCheck -check-prefix CHECK-ZIPPERED %s
 
 // RUN: %swift_driver -print-target-info -target x86_64-apple-ios12.0 | %FileCheck -check-prefix CHECK-IOS-SIM %s
 
@@ -90,14 +90,14 @@
 // CHECK-PRE-CONCURRENCY-ZIPPERED: }
 
 // CHECK-ZIPPERED: "target": {
-// CHECK-ZIPPERED:   "triple": "x86_64-apple-macosx12.0"
+// CHECK-ZIPPERED:   "triple": "x86_64-apple-macosx26.0"
 // CHECK-ZIPPERED:   "unversionedTriple": "x86_64-apple-macosx"
 // CHECK-ZIPPERED:   "moduleTriple": "x86_64-apple-macos"
 // CHECK-ZIPPERED:   "librariesRequireRPath": false
 // CHECK-ZIPPERED: }
 
 // CHECK-ZIPPERED: "targetVariant": {
-// CHECK-ZIPPERED:   "triple": "x86_64-apple-ios15-macabi"
+// CHECK-ZIPPERED:   "triple": "x86_64-apple-ios26-macabi"
 // CHECK-ZIPPERED:   "unversionedTriple": "x86_64-apple-ios-macabi"
 // CHECK-ZIPPERED:   "moduleTriple": "x86_64-apple-ios-macabi"
 // CHECK-ZIPPERED:   "librariesRequireRPath": false
diff --git a/test/Driver/working-directory.swift b/test/Driver/working-directory.swift
index 26919e89d6472..b5ab72fab7f65 100644
--- a/test/Driver/working-directory.swift
+++ b/test/Driver/working-directory.swift
@@ -32,10 +32,10 @@
 // RUN: cd %t && %swiftc_driver -driver-print-jobs -working-directory %/S/Inputs -emit-executable %/s -L=. | %FileCheck %s -check-prefix=L_PATH
 // L_PATH: -L {{"?}}SOURCE_DIR/test/Driver/Inputs
 
-// RUN: cd %t && %swiftc_driver -driver-print-jobs -working-directory %/S/Inputs -c %/s -disable-bridging-pch -import-objc-header bridging-header.h | %FileCheck %s -check-prefix=OBJC_HEADER1
-// OBJC_HEADER1: -import-objc-header {{"?}}SOURCE_DIR/test/Driver/Inputs{{/|\\\\}}bridging-header.h
+// RUN: cd %t && %swiftc_driver -driver-print-jobs -working-directory %/S/Inputs -c %/s -disable-bridging-pch -import-bridging-header bridging-header.h | %FileCheck %s -check-prefix=OBJC_HEADER1
+// OBJC_HEADER1: -import-bridging-header {{"?}}SOURCE_DIR/test/Driver/Inputs{{/|\\\\}}bridging-header.h
 
-// RUN: cd %t && %swiftc_driver -driver-print-jobs -working-directory %/S/Inputs -c %/s -enable-bridging-pch -import-objc-header bridging-header.h | %FileCheck %s -check-prefix=OBJC_HEADER2
+// RUN: cd %t && %swiftc_driver -driver-print-jobs -working-directory %/S/Inputs -c %/s -enable-bridging-pch -import-bridging-header bridging-header.h | %FileCheck %s -check-prefix=OBJC_HEADER2
 // OBJC_HEADER2: SOURCE_DIR/test/Driver/Inputs{{/|\\\\}}bridging-header.h{{"? .*}}-emit-pch
 
 // RUN: cd %t && %swiftc_driver -driver-print-jobs -working-directory %/S/Inputs -c %/s -o main.o | %FileCheck %s -check-prefix=OUTPUT_OBJ
diff --git a/test/FixCode/Inputs/batch-mode-helper.swift b/test/FixCode/Inputs/batch-mode-helper.swift
deleted file mode 100644
index 8b3bcbdc95d1e..0000000000000
--- a/test/FixCode/Inputs/batch-mode-helper.swift
+++ /dev/null
@@ -1,10 +0,0 @@
-enum E2 {
-  case x
-  case y
-  case z
-}
-
-func fooHelper(_ e: E2) {
-  switch e {
-  }
-}
diff --git a/test/FixCode/Inputs/module.modulemap b/test/FixCode/Inputs/module.modulemap
deleted file mode 100644
index ca6aa1181a531..0000000000000
--- a/test/FixCode/Inputs/module.modulemap
+++ /dev/null
@@ -1 +0,0 @@
-module Empty {}
diff --git a/test/FixCode/Inputs/t1.swift b/test/FixCode/Inputs/t1.swift
deleted file mode 100644
index 1ad30c6f0ba4a..0000000000000
--- a/test/FixCode/Inputs/t1.swift
+++ /dev/null
@@ -1,8 +0,0 @@
-func foo1() {
-	class Base {}
-	class Derived : Base {}
-
-	var b : Base
-	b as Derived
-	undeclared_foo1
-}
diff --git a/test/FixCode/Inputs/t1.swift.result b/test/FixCode/Inputs/t1.swift.result
deleted file mode 100644
index e452c83a9b373..0000000000000
--- a/test/FixCode/Inputs/t1.swift.result
+++ /dev/null
@@ -1,8 +0,0 @@
-func foo1() {
-	class Base {}
-	class Derived : Base {}
-
-	var b : Base
-	b as! Derived
-	undeclared_foo1
-}
diff --git a/test/FixCode/Inputs/t2.swift b/test/FixCode/Inputs/t2.swift
deleted file mode 100644
index ae23093b95e83..0000000000000
--- a/test/FixCode/Inputs/t2.swift
+++ /dev/null
@@ -1,8 +0,0 @@
-func foo2() {
-	class Base {}
-	class Derived : Base {}
-
-	var b : Base
-	b as Derived
-	undeclared_foo2
-}
diff --git a/test/FixCode/Inputs/t2.swift.result b/test/FixCode/Inputs/t2.swift.result
deleted file mode 100644
index 4945b3f608196..0000000000000
--- a/test/FixCode/Inputs/t2.swift.result
+++ /dev/null
@@ -1,8 +0,0 @@
-func foo2() {
-	class Base {}
-	class Derived : Base {}
-
-	var b : Base
-	b as! Derived
-	undeclared_foo2
-}
diff --git a/test/FixCode/batch-mode.swift b/test/FixCode/batch-mode.swift
deleted file mode 100644
index affc27fa01648..0000000000000
--- a/test/FixCode/batch-mode.swift
+++ /dev/null
@@ -1,24 +0,0 @@
-// RUN: not %target-swift-frontend -typecheck -primary-file %s  -emit-fixits-path %t.main.remap -primary-file %S/Inputs/batch-mode-helper.swift -emit-fixits-path %t.helper.remap
-// RUN: %FileCheck -check-prefix=CHECK-MAIN %s < %t.main.remap
-// RUN: %FileCheck -check-prefix=NEGATIVE-MAIN %s < %t.main.remap
-// RUN: %FileCheck -check-prefix=CHECK-HELPER %s < %t.helper.remap
-// RUN: %FileCheck -check-prefix=NEGATIVE-HELPER %s < %t.helper.remap
-
-// CHECK-MAIN: "file": "{{.+}}batch-mode.swift"
-// CHECK-MAIN: "text": "case .a:\n<#code#>\ncase .b:\n<#code#>\ncase .c:\n<#code#>\n"
-// NEGATIVE-MAIN-NOT: batch-mode-helper.swift
-
-// CHECK-HELPER: "file": "{{.+}}batch-mode-helper.swift"
-// CHECK-HELPER: "text": "case .x:\n<#code#>\ncase .y:\n<#code#>\ncase .z:\n<#code#>\n"
-// NEGATIVE-HELPER-NOT: batch-mode.swift
-
-enum E1 {
-  case a
-  case b
-  case c
-}
-
-func fooMain(_ e: E1) {
-  switch e {
-  }
-}
diff --git a/test/FixCode/fixit-all.swift b/test/FixCode/fixit-all.swift
new file mode 100644
index 0000000000000..00e0de2c1d7b2
--- /dev/null
+++ b/test/FixCode/fixit-all.swift
@@ -0,0 +1,5 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -typecheck -fixit-all -emit-fixits-path %t.remap %s 2>&1 | %FileCheck %s
+
+// CHECK: <unknown>:0: warning: ignoring '-fixit-all'; this option is obsolete
+// CHECK: <unknown>:0: warning: ignoring '-emit-fixits-path'; this option is obsolete
diff --git a/test/FixCode/fixits-apply-all.swift b/test/FixCode/fixits-apply-all.swift
deleted file mode 100644
index 2b7ec0310f90a..0000000000000
--- a/test/FixCode/fixits-apply-all.swift
+++ /dev/null
@@ -1,26 +0,0 @@
-// This tests whether we accept fixits from warnings without filtering.
-// The particular diagnostics used are not important.
-
-// RUN: %swift -typecheck -target %target-triple %s -fixit-all -emit-fixits-path %t.remap
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
-
-func ftest1() {
-  let myvar = 0
-}
-
-func foo() -> Int {
-  do {
-  } catch var err {
-    goo(err)
-  }
-}
-func goo(_ e: Error) {
-
-}
-
-@warn_unused_result(message="test message")
-func warn_unused_result_removal() -> Int { return 5 }
-
-@discardableResult func discardableResultOnVoidFunc() {}
-
-@discardableResult func discardableResultOnNeverFunc() -> Never { fatalError() }
diff --git a/test/FixCode/fixits-apply-all.swift.result b/test/FixCode/fixits-apply-all.swift.result
deleted file mode 100644
index af4204def1c16..0000000000000
--- a/test/FixCode/fixits-apply-all.swift.result
+++ /dev/null
@@ -1,26 +0,0 @@
-// This tests whether we accept fixits from warnings without filtering.
-// The particular diagnostics used are not important.
-
-// RUN: %swift -typecheck -target %target-triple %s -fixit-all -emit-fixits-path %t.remap
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
-
-func ftest1() {
-  _ = 0
-}
-
-func foo() -> Int {
-  do {
-  } catch let err {
-    goo(err)
-  }
-}
-func goo(_ e: Error) {
-
-}
-
-
-func warn_unused_result_removal() -> Int { return 5 }
-
-func discardableResultOnVoidFunc() {}
-
-func discardableResultOnNeverFunc() -> Never { fatalError() }
diff --git a/test/FixCode/fixits-apply-objc.swift b/test/FixCode/fixits-apply-objc.swift
deleted file mode 100644
index 505bce01daccb..0000000000000
--- a/test/FixCode/fixits-apply-objc.swift
+++ /dev/null
@@ -1,111 +0,0 @@
-// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-objc-attr-requires-foundation-module -typecheck %s -emit-fixits-path %t.remap
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
-import ObjectiveC
-
-// REQUIRES: objc_interop
-
-@objc class Selectors {
-  func takeSel(_: Selector) {}
-  @objc func mySel() {}
-  func test() {
-    takeSel("mySel")
-    takeSel(Selector("mySel"))
-  }
-}
-
-@objc class OtherClass {
-  func test(s: Selectors) {
-    s.takeSel("mySel")
-    s.takeSel(Selector("mySel"))
-  }
-}
-
-@objc class Base {
-  @objc func baseSel() {}
-}
-
-@objc class Outer {
-  func takeSel(_: Selector) {}
-  @objc func outerSel() {}
-
-  @objc class Inner: Base {
-    func takeSel(_: Selector) {}
-
-    @objc func innerSel() {}
-
-    func test(s: Selectors, o: Outer) {
-      s.takeSel("mySel")
-      s.takeSel(Selector("mySel"))
-
-      takeSel("innerSel")
-      takeSel(Selector("innerSel"))
-
-      takeSel("baseSel")
-      takeSel(Selector("baseSel"))
-
-      o.takeSel("outerSel")
-      o.takeSel(Selector("outerSel"))
-    }
-  }
-
-  func test(s: Selectors, i: Inner) {
-    s.takeSel("mySel")
-    s.takeSel(Selector("mySel"))
-
-    i.takeSel("innerSel")
-    i.takeSel(Selector("innerSel"))
-
-    i.takeSel("baseSel")
-    i.takeSel(Selector("baseSel"))
-
-    takeSel("outerSel")
-    takeSel(Selector("outerSel"))
-  }
-}
-
-extension Outer {
-  func test2(s: Selectors, i: Inner) {
-    s.takeSel("mySel")
-    s.takeSel(Selector("mySel"))
-
-    i.takeSel("innerSel")
-    i.takeSel(Selector("innerSel"))
-
-    i.takeSel("baseSel")
-    i.takeSel(Selector("baseSel"))
-
-    takeSel("outerSel")
-    takeSel(Selector("outerSel"))
-  }
-}
-
-func freeTest(s: Selectors, o: Outer, i: Outer.Inner) {
-  s.takeSel("mySel")
-  s.takeSel(Selector("mySel"))
-
-  i.takeSel("innerSel")
-  i.takeSel(Selector("innerSel"))
-
-  i.takeSel("baseSel")
-  i.takeSel(Selector("baseSel"))
-
-  o.takeSel("outerSel")
-  o.takeSel(Selector("outerSel"))
-}
-
-func foo(an : Any) {
-  let a1 : AnyObject
-  a1 = an
-  let a2 : AnyObject?
-  a2 = an
-  let a3 : AnyObject!
-  a3 = an
-}
-
-func foo1(_ an : Any) {
-  let obj: AnyObject = an
-}
-
-func foo2(_ messageData: Any?) -> AnyObject? {
-  return messageData
-}
diff --git a/test/FixCode/fixits-apply-objc.swift.result b/test/FixCode/fixits-apply-objc.swift.result
deleted file mode 100644
index d31139051bb06..0000000000000
--- a/test/FixCode/fixits-apply-objc.swift.result
+++ /dev/null
@@ -1,111 +0,0 @@
-// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-objc-attr-requires-foundation-module -typecheck %s -emit-fixits-path %t.remap
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
-import ObjectiveC
-
-// REQUIRES: objc_interop
-
-@objc class Selectors {
-  func takeSel(_: Selector) {}
-  @objc func mySel() {}
-  func test() {
-    takeSel(#selector(self.mySel))
-    takeSel(#selector(self.mySel))
-  }
-}
-
-@objc class OtherClass {
-  func test(s: Selectors) {
-    s.takeSel(#selector(Selectors.mySel))
-    s.takeSel(#selector(Selectors.mySel))
-  }
-}
-
-@objc class Base {
-  @objc func baseSel() {}
-}
-
-@objc class Outer {
-  func takeSel(_: Selector) {}
-  @objc func outerSel() {}
-
-  @objc class Inner: Base {
-    func takeSel(_: Selector) {}
-
-    @objc func innerSel() {}
-
-    func test(s: Selectors, o: Outer) {
-      s.takeSel(#selector(Selectors.mySel))
-      s.takeSel(#selector(Selectors.mySel))
-
-      takeSel(#selector(self.innerSel))
-      takeSel(#selector(self.innerSel))
-
-      takeSel(#selector(self.baseSel))
-      takeSel(#selector(self.baseSel))
-
-      o.takeSel(#selector(Outer.outerSel))
-      o.takeSel(#selector(Outer.outerSel))
-    }
-  }
-
-  func test(s: Selectors, i: Inner) {
-    s.takeSel(#selector(Selectors.mySel))
-    s.takeSel(#selector(Selectors.mySel))
-
-    i.takeSel(#selector(Inner.innerSel))
-    i.takeSel(#selector(Inner.innerSel))
-
-    i.takeSel(#selector(Base.baseSel))
-    i.takeSel(#selector(Base.baseSel))
-
-    takeSel(#selector(self.outerSel))
-    takeSel(#selector(self.outerSel))
-  }
-}
-
-extension Outer {
-  func test2(s: Selectors, i: Inner) {
-    s.takeSel(#selector(Selectors.mySel))
-    s.takeSel(#selector(Selectors.mySel))
-
-    i.takeSel(#selector(Inner.innerSel))
-    i.takeSel(#selector(Inner.innerSel))
-
-    i.takeSel(#selector(Base.baseSel))
-    i.takeSel(#selector(Base.baseSel))
-
-    takeSel(#selector(self.outerSel))
-    takeSel(#selector(self.outerSel))
-  }
-}
-
-func freeTest(s: Selectors, o: Outer, i: Outer.Inner) {
-  s.takeSel(#selector(Selectors.mySel))
-  s.takeSel(#selector(Selectors.mySel))
-
-  i.takeSel(#selector(Inner.innerSel))
-  i.takeSel(#selector(Inner.innerSel))
-
-  i.takeSel(#selector(Base.baseSel))
-  i.takeSel(#selector(Base.baseSel))
-
-  o.takeSel(#selector(Outer.outerSel))
-  o.takeSel(#selector(Outer.outerSel))
-}
-
-func foo(an : Any) {
-  let a1 : AnyObject
-  a1 = an as AnyObject
-  let a2 : AnyObject?
-  a2 = an as AnyObject
-  let a3 : AnyObject!
-  a3 = an as AnyObject
-}
-
-func foo1(_ an : Any) {
-  let obj: AnyObject = an as AnyObject
-}
-
-func foo2(_ messageData: Any?) -> AnyObject? {
-  return messageData as AnyObject
-}
diff --git a/test/FixCode/fixits-apply.swift b/test/FixCode/fixits-apply.swift
deleted file mode 100644
index eee2c6bddbc4d..0000000000000
--- a/test/FixCode/fixits-apply.swift
+++ /dev/null
@@ -1,318 +0,0 @@
-// FIXME(integers): the test started to fail with the new integer protocols
-// XFAIL: *
-
-// RUN: not %swift -typecheck -target %target-triple %s -emit-fixits-path %t.remap -I %S/Inputs
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
-
-class Base {}
-class Derived : Base {}
-
-var b : Base
-b as Derived
-b as Derived
-
-b as! Base
-
-var opti : Int?
-// Add bang.
-var i : Int = opti
-// But remove unnecessary bang.
-var i2 : Int = i!
-
-struct MyMask : OptionSet {
-  init(_ rawValue: UInt) {}
-  init(rawValue: UInt) {}
-  init(nilLiteral: ()) {}
-
-  var rawValue: UInt { return 0 }
-
-  static var allZeros: MyMask { return MyMask(0) }
-  static var Bingo: MyMask { return MyMask(1) }
-}
-
-let _: MyMask = 0
-
-func supported() -> MyMask {
-  return Int(MyMask.Bingo.rawValue)
-}
-
-struct MyEventMask2 : OptionSet {
-  init(rawValue: UInt64) {}
-  var rawValue: UInt64 { return 0 }
-}
-func sendIt(_: MyEventMask2) {}
-func sendItOpt(_: MyEventMask2?) {}
-func sendItOpt3(_: MyEventMask2???) {}
-func testMask1(a: Int) {
-  sendIt(a)
-}
-func testMask2(a: UInt64) {
-  sendIt(a)
-}
-func testMask3(a: MyEventMask2) {
-  testMask1(a: a)
-}
-func testMask4(a: MyEventMask2) {
-  testMask2(a: a)
-}
-func testMask5(a: Int) {
-  sendItOpt(a)
-}
-func testMask6(a: Int) {
-  sendItOpt(a)
-}
-func testMask7(a: Int?) {
-  sendItOpt(a)
-}
-func testMask8(a: UInt64?) {
-  sendItOpt(a)
-}
-func testMask9(a: Any) {
-  sendItOpt(a as? Int)
-}
-func testMask10(a: Int?) {
-  sendIt(a) // no fix, nullability mismatch.
-}
-func testMask11(a: MyEventMask2?) {
-  testMask7(a: a)
-}
-func testMask12(a: MyEventMask2?) {
-  testMask8(a: a)
-}
-func testMask13(a: MyEventMask2?) {
-  testMask1(a: a) // no fix, nullability mismatch.
-}
-func testMask14() {
-  sendIt(1)
-  sendItOpt(2)
-}
-
-struct Wrapper {
-  typealias InnerMask = MyEventMask2
-}
-func sendItInner(_: Wrapper.InnerMask) {}
-func testInnerMask(a: UInt64) {
-  sendItInner(a)
-}
-
-struct SomeName : RawRepresentable {
-  init(_ rawValue: String) {}
-  init(rawValue: String) {}
-  var rawValue: String { return "" }
-}
-func testPassSomeName(_: SomeName) {}
-func testConvertSomeName(s: String) {
-  testPassSomeName("\(s)}")
-}
-
-class WrappedClass {}
-class WrappedClassSub: WrappedClass {}
-struct ClassWrapper : RawRepresentable {
-  var rawValue: WrappedClass
-}
-func testPassAnyObject(_: AnyObject) {}
-func testPassAnyObjectOpt(_: AnyObject?) {}
-func testPassWrappedSub(_: WrappedClassSub) {}
-func testConvertClassWrapper(_ x: ClassWrapper, _ sub: WrappedClassSub) {
-  testPassAnyObject(x)
-  testPassAnyObjectOpt(x)
-  testPassWrappedSub(x)
-
-  let iuo: ClassWrapper! = x
-  testPassAnyObject(iuo)
-  testPassAnyObjectOpt(iuo)
-
-  let _: ClassWrapper = sub
-  let _: ClassWrapper = x.rawValue
-  // FIXME: This one inserts 'as!', which is incorrect.
-  let _: ClassWrapper = sub as AnyObject
-}
-
-enum MyEnumType : UInt32 {
-  case invalid
-}
-_ = MyEnumType(MyEnumType.invalid)
-
-func goo(var e : Error) {
-}
-func goo2(var e: Error) {}
-func goo3(var e: Int) { e = 3 }
-protocol A {
-  func bar(var s: Int)
-}
-extension A {
-  func bar(var s: Int) {
-    s += 5
-  }
-}
-
-func baz(var x: Int) {
-  x += 10
-}
-func foo(let y: String, inout x: Int) {
-
-}
-
-struct Test1 : OptionSet {
-  init(rawValue: Int) {}
-  var rawValue: Int { return 0 }
-}
-
-print("", false)
-
-func ftest1() {
-  // Don't replace the variable name with '_'
-  let myvar = 0
-}
-
-func ftest2(x x: @escaping Int -> Int) {}
-
-protocol SomeProt {
-  func protMeth(p: Int)
-}
-@objc protocol SomeObjCProt {
-  func objcprotMeth(p: Int)
-}
-class Test2 : SomeProt, SomeObjCProt {
-  func protMeth(_ p: Int) {}
-
-  func instMeth(p: Int) {}
-  func instMeth2(p: Int, p2: Int) {}
-  func objcprotMeth(_ p: Int) {}
-}
-@objc class Test3 : SomeObjCProt {
-  func objcprotMeth(_ p: Int) {}
-}
-class SubTest2 : Test2 {
-  override func instMeth(_ p: Int) {}
-}
-Test2().instMeth(0)
-Test2().instMeth2(0, p2:1)
-
-func recit(_: Int32) {}
-func ftest3(_ fd: CInt) {
-  recit(UInt(fd))
-}
-func ftest4(_ fd: UInt) {
-  recit(fd)
-}
-
-func letToVar1() {
-  let x = 1
-  if x == 2 {
-    x += 3
-  }
-  let y = ""
-  y.append("as")
-  y.append("df")
-}
-
-class Node  {}
-class Graph<NodeType : Node> {}
-var graph: Graph
-
-class Node2  {}
-class Graph2<NodeType1 : Node, NodeType2 : Node2> {}
-var graph: Graph2
-
-@objc protocol ObjCProt { }
-class Graph3<NodeType : ObjCProt> {}
-var graph: Graph3
-
-class Graph4<NodeType : SomeProt> {}
-var graph: Graph4
-var graphAgain = Graph4()
-
-class GraphCombo<NodeType : SomeProt & ObjCProt> {}
-var graph: GraphCombo
-
-func evilCommas(s: String) {
-  _ = s[s.startIndex..<<#editorplaceholder#>]
-  _ = true ? s[s.startIndex..<<#editorplaceholder#>] : ""
-  _ = [s.startIndex..<<#editorplaceholder#>]
-}
-
-import Empty
-func testGenericSig(x: Empty<Int>) -> Empty<String> {}
-
-class NonObjC {}
-protocol NonObjCProtocol {}
-@objc class IBIssues {
-  @IBOutlet static private var ibout1: IBIssues!
-  @IBOutlet private var ibout2: NonObjC!
-  @IBOutlet private var ibout3: NonObjCProtocol!
-  @IBOutlet private let ibout4: IBIssues!
-  @IBOutlet private var ibout5: [[IBIssues]]!
-  @IBOutlet private var ibout6: [String: String]!
-  @IBInspectable static private var ibinspect1: IBIssues!
-  @IBAction static func ibact() {}
-  @IBSegueAction static func ibsegact(_: String, _: IBIssues) -> IBIssues { return self }
-}
-
-@IBDesignable extension SomeProt {}
-
-func attrNowOnType(foo: ()->()) {}
-
-class InitDynType {
-  init() {}
-  func notInit() {
-    self.init()
-  }
-}
-
-class NoSemi {
-  enum Bar { case bar }
-  var foo: .Bar = .bar
-}
-
-func fnWithClosure(c: @escaping ()->()) {}
-func testescape(rec: ()->()) {
-  fnWithClosure { rec() }
-}
-
-@warn_unused_result func testDeprecatedAttr() -> Int { return 0 }
-
-protocol Prot1 {}
-protocol Prot2 {
-  associatedtype Ty = Prot1
-}
-class Cls1 : Prot1 {}
-func testwhere<T: Prot2 where T.Ty == Cls1>(_: T) {}
-
-enum E {
-  case abc
-}
-func testEnumRename() { _ = E.Abc }
-
-func testAnyToAnyObject(x: Any) {
-  x.instMeth(p: 1)
-}
-
-func testProtocolCompositionSyntax() {
-  var _: protocol<>
-  var _: protocol<Prot1>
-  var _: protocol<Prot1, Prot2>
-}
-
-func disable_unnamed_param_reorder(p: Int, _: String) {}
-disable_unnamed_param_reorder(0, "") // no change.
-
-prefix operator ***** {}
-
-class BoolFoo : BooleanType {
-  var boolValue: Bool {return false}
-}
-func testBoolValue(a : BoolFoo) {
-  if a { }
-  guard a {}
-  if a as BoolFoo {}
-}
-
-protocol P1 {}
-protocol P2 {}
-var a : protocol<P1, P2>?
-var a2 : protocol<P1>= 17
-
-class TestOptionalMethodFixit {
-  optional func test() {}
-}
diff --git a/test/FixCode/fixits-apply.swift.result b/test/FixCode/fixits-apply.swift.result
deleted file mode 100644
index 5cb79ac3b70b3..0000000000000
--- a/test/FixCode/fixits-apply.swift.result
+++ /dev/null
@@ -1,318 +0,0 @@
-// RUN: not %swift -typecheck -target %target-triple %s -emit-fixits-path %t.remap -I %S/Inputs
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
-
-class Base {}
-class Derived : Base {}
-
-var b : Base
-b as! Derived
-b as! Derived
-
-b 
-
-var opti : Int?
-// Add bang.
-var i : Int = opti!
-// But remove unnecessary bang.
-var i2 : Int = i
-
-struct MyMask : OptionSet {
-  init(_ rawValue: UInt) {}
-  init(rawValue: UInt) {}
-  init(nilLiteral: ()) {}
-
-  var rawValue: UInt { return 0 }
-
-  static var allZeros: MyMask { return MyMask(0) }
-  static var Bingo: MyMask { return MyMask(1) }
-}
-
-let _: MyMask = []
-
-func supported() -> MyMask {
-  return MyMask(rawValue: UInt(MyMask.Bingo))
-}
-
-struct MyEventMask2 : OptionSet {
-  init(rawValue: UInt64) {}
-  var rawValue: UInt64 { return 0 }
-}
-func sendIt(_: MyEventMask2) {}
-func sendItOpt(_: MyEventMask2?) {}
-func sendItOpt3(_: MyEventMask2???) {}
-func testMask1(a: Int) {
-  sendIt(MyEventMask2(rawValue: UInt64(a)))
-}
-func testMask2(a: UInt64) {
-  sendIt(MyEventMask2(rawValue: a))
-}
-func testMask3(a: MyEventMask2) {
-  testMask1(a: Int(a.rawValue))
-}
-func testMask4(a: MyEventMask2) {
-  testMask2(a: a.rawValue)
-}
-func testMask5(a: Int) {
-  sendItOpt(MyEventMask2(rawValue: UInt64(a)))
-}
-func testMask6(a: Int) {
-  sendItOpt(MyEventMask2(rawValue: UInt64(a)))
-}
-func testMask7(a: Int?) {
-  sendItOpt(a.map { MyEventMask2(rawValue: UInt64($0)) })
-}
-func testMask8(a: UInt64?) {
-  sendItOpt(a.map { MyEventMask2(rawValue: $0) })
-}
-func testMask9(a: Any) {
-  sendItOpt((a as? Int).map { MyEventMask2(rawValue: UInt64($0)) })
-}
-func testMask10(a: Int?) {
-  sendIt(a) // no fix, nullability mismatch.
-}
-func testMask11(a: MyEventMask2?) {
-  testMask7(a: a.map { Int($0.rawValue) })
-}
-func testMask12(a: MyEventMask2?) {
-  testMask8(a: a.map { $0.rawValue })
-}
-func testMask13(a: MyEventMask2?) {
-  testMask1(a: a) // no fix, nullability mismatch.
-}
-func testMask14() {
-  sendIt(MyEventMask2(rawValue: 1))
-  sendItOpt(MyEventMask2(rawValue: 2))
-}
-
-struct Wrapper {
-  typealias InnerMask = MyEventMask2
-}
-func sendItInner(_: Wrapper.InnerMask) {}
-func testInnerMask(a: UInt64) {
-  sendItInner(Wrapper.InnerMask(rawValue: a))
-}
-
-struct SomeName : RawRepresentable {
-  init(_ rawValue: String) {}
-  init(rawValue: String) {}
-  var rawValue: String { return "" }
-}
-func testPassSomeName(_: SomeName) {}
-func testConvertSomeName(s: String) {
-  testPassSomeName(SomeName(rawValue: "\(s)}"))
-}
-
-class WrappedClass {}
-class WrappedClassSub: WrappedClass {}
-struct ClassWrapper : RawRepresentable {
-  var rawValue: WrappedClass
-}
-func testPassAnyObject(_: AnyObject) {}
-func testPassAnyObjectOpt(_: AnyObject?) {}
-func testPassWrappedSub(_: WrappedClassSub) {}
-func testConvertClassWrapper(_ x: ClassWrapper, _ sub: WrappedClassSub) {
-  testPassAnyObject(x.rawValue)
-  testPassAnyObjectOpt(x.rawValue)
-  testPassWrappedSub(x)
-
-  let iuo: ClassWrapper! = x
-  testPassAnyObject(iuo)
-  testPassAnyObjectOpt(iuo.map { $0.rawValue })
-
-  let _: ClassWrapper = ClassWrapper(rawValue: sub)
-  let _: ClassWrapper = ClassWrapper(rawValue: x.rawValue)
-  // FIXME: This one inserts 'as!', which is incorrect.
-  let _: ClassWrapper = sub as AnyObject as! ClassWrapper
-}
-
-enum MyEnumType : UInt32 {
-  case invalid
-}
-_ = MyEnumType.invalid
-
-func goo(e : Error) {
-    var e = e
-}
-func goo2(e: Error) { var e = e }
-func goo3(e: Int) { var e = e; e = 3 }
-protocol A {
-  func bar(s: Int)
-}
-extension A {
-  func bar(s: Int) {
-    var s = s
-    s += 5
-  }
-}
-
-func baz(x: Int) {
-  var x = x
-  x += 10
-}
-func foo(y: String, x: inout Int) {
-
-}
-
-struct Test1 : OptionSet {
-  init(rawValue: Int) {}
-  var rawValue: Int { return 0 }
-}
-
-print("", false)
-
-func ftest1() {
-  // Don't replace the variable name with '_'
-  let myvar = 0
-}
-
-func ftest2(x: @escaping (Int) -> Int) {}
-
-protocol SomeProt {
-  func protMeth(p: Int)
-}
-@objc protocol SomeObjCProt {
-  func objcprotMeth(p: Int)
-}
-class Test2 : SomeProt, SomeObjCProt {
-  func protMeth(_ p: Int) {}
-
-  func instMeth(p: Int) {}
-  func instMeth2(p: Int, p2: Int) {}
-  func objcprotMeth(_ p: Int) {}
-}
-@objc class Test3 : SomeObjCProt {
-  func objcprotMeth(_ p: Int) {}
-}
-class SubTest2 : Test2 {
-  override func instMeth(_ p: Int) {}
-}
-Test2().instMeth(0)
-Test2().instMeth2(0, p2:1)
-
-func recit(_: Int32) {}
-func ftest3(_ fd: CInt) {
-  recit(fd)
-}
-func ftest4(_ fd: UInt) {
-  recit(Int32(fd))
-}
-
-func letToVar1() {
-  var x = 1
-  if x == 2 {
-    x += 3
-  }
-  var y = ""
-  y.append("as")
-  y.append("df")
-}
-
-class Node  {}
-class Graph<NodeType : Node> {}
-var graph: Graph<Node>
-
-class Node2  {}
-class Graph2<NodeType1 : Node, NodeType2 : Node2> {}
-var graph: Graph2<Node, Node2>
-
-@objc protocol ObjCProt { }
-class Graph3<NodeType : ObjCProt> {}
-var graph: Graph3<ObjCProt>
-
-class Graph4<NodeType : SomeProt> {}
-var graph: Graph4<<#NodeType: SomeProt#>>
-var graphAgain = Graph4<<#NodeType: SomeProt#>>()
-
-class GraphCombo<NodeType : SomeProt & ObjCProt> {}
-var graph: GraphCombo<<#NodeType: ObjCProt & SomeProt#>>
-
-func evilCommas(s: String) {
-  _ = s[s.startIndex..<<#editorplaceholder#>]
-  _ = true ? s[s.startIndex..<<#editorplaceholder#>] : ""
-  _ = [s.startIndex..<<#editorplaceholder#>]
-}
-
-import Empty
-func testGenericSig(x: Empty<Int>) -> Empty<String> {}
-
-class NonObjC {}
-protocol NonObjCProtocol {}
-@objc class IBIssues {
-  @IBOutlet static private var ibout1: IBIssues!
-  @IBOutlet private var ibout2: NonObjC!
-  @IBOutlet private var ibout3: NonObjCProtocol!
-  @IBOutlet private let ibout4: IBIssues!
-  @IBOutlet private var ibout5: [[IBIssues]]!
-  @IBOutlet private var ibout6: [String: String]!
-  @IBInspectable static private var ibinspect1: IBIssues!
-  @IBAction static func ibact() {}
-  @IBSegueAction static func ibsegact(_: String, _: IBIssues) -> IBIssues { return self }
-}
-
-@IBDesignable extension SomeProt {}
-
-func attrNowOnType(foo: ()->()) {}
-
-class InitDynType {
-  init() {}
-  func notInit() {
-    self.init()
-  }
-}
-
-class NoSemi {
-  enum Bar { case bar }
-  var foo: .Bar = .bar
-}
-
-func fnWithClosure(c: @escaping ()->()) {}
-func testescape(rec: @escaping ()->()) {
-  fnWithClosure { rec() }
-}
-
-func testDeprecatedAttr() -> Int { return 0 }
-
-protocol Prot1 {}
-protocol Prot2 {
-  associatedtype Ty = Prot1
-}
-class Cls1 : Prot1 {}
-func testwhere<T: Prot2>(_: T) where T.Ty == Cls1 {}
-
-enum E {
-  case abc
-}
-func testEnumRename() { _ = E.Abc }
-
-func testAnyToAnyObject(x: Any) {
-  (x as AnyObject).instMeth(p: 1)
-}
-
-func testProtocolCompositionSyntax() {
-  var _: Any
-  var _: Prot1
-  var _: Prot1 & Prot2
-}
-
-func disable_unnamed_param_reorder(p: Int, _: String) {}
-disable_unnamed_param_reorder(0, "") // no change.
-
-prefix operator *****
-
-class BoolFoo : Bool {
-  var boolValue: Bool {return false}
-}
-func testBoolValue(a : BoolFoo) {
-  if a.boolValue { }
-  guard a.boolValue {}
-  if (a as BoolFoo).boolValue {}
-}
-
-protocol P1 {}
-protocol P2 {}
-var a : (P1 & P2)?
-var a2 : P1= 17 as! P1
-
-class TestOptionalMethodFixit {
-  func test() {}
-}
diff --git a/test/FixCode/fixits-if-else.swift b/test/FixCode/fixits-if-else.swift
deleted file mode 100644
index 1121fbbdfed3f..0000000000000
--- a/test/FixCode/fixits-if-else.swift
+++ /dev/null
@@ -1,34 +0,0 @@
-// RUN: not %swift -emit-sil -target %target-triple %s -emit-fixits-path %t.remap -I %S/Inputs
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
-
-func something() -> Bool { return true }
-
-func foo1() {
-    if something() {
-    } else
-}
-
-func foo2() {
-    if something() {
-    } else
-    foo1()
-}
-
-func foo3() {
-    if something() {
-    } else something() { // all on one line, 'if' inserted
-    }
-}
-
-func foo4() {
-    if something() {
-    } else something()
-    {
-    }
-}
-
-func foo5() {
-    if something() {
-    } else something()
-    foo1()
-}
diff --git a/test/FixCode/fixits-if-else.swift.result b/test/FixCode/fixits-if-else.swift.result
deleted file mode 100644
index 4b9bb9475cce0..0000000000000
--- a/test/FixCode/fixits-if-else.swift.result
+++ /dev/null
@@ -1,34 +0,0 @@
-// RUN: not %swift -emit-sil -target %target-triple %s -emit-fixits-path %t.remap -I %S/Inputs
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
-
-func something() -> Bool { return true }
-
-func foo1() {
-    if something() {
-    } else
-}
-
-func foo2() {
-    if something() {
-    } else
-    foo1()
-}
-
-func foo3() {
-    if something() {
-    } else if something() { // all on one line, 'if' inserted
-    }
-}
-
-func foo4() {
-    if something() {
-    } else something()
-    {
-    }
-}
-
-func foo5() {
-    if something() {
-    } else something()
-    foo1()
-}
diff --git a/test/Frontend/Inputs/broken-c-module/broken_c.h b/test/Frontend/DiagnosticVerifier/Inputs/broken-c-module/broken_c.h
similarity index 100%
rename from test/Frontend/Inputs/broken-c-module/broken_c.h
rename to test/Frontend/DiagnosticVerifier/Inputs/broken-c-module/broken_c.h
diff --git a/test/Frontend/Inputs/broken-c-module/module.modulemap b/test/Frontend/DiagnosticVerifier/Inputs/broken-c-module/module.modulemap
similarity index 100%
rename from test/Frontend/Inputs/broken-c-module/module.modulemap
rename to test/Frontend/DiagnosticVerifier/Inputs/broken-c-module/module.modulemap
diff --git a/test/Frontend/DiagnosticVerifier/broken-c-module.swift b/test/Frontend/DiagnosticVerifier/broken-c-module.swift
new file mode 100644
index 0000000000000..53bc147105eb2
--- /dev/null
+++ b/test/Frontend/DiagnosticVerifier/broken-c-module.swift
@@ -0,0 +1,16 @@
+// Tests that `-verify` mode outputs diagnostics from a failing C module
+// compilation.
+// This needs to be a separate test from verify.swift because compilation will
+// terminate after the failing import statement.
+
+// RUN: not %target-typecheck-verify-swift -I %S/Inputs/broken-c-module 2>&1 | %FileCheck %s --implicit-check-not error: --implicit-check-not note: --implicit-check-not warning:
+
+// CHECK: <unknown>:0: error: fatal error encountered while in -verify mode
+// CHECK: [[@LINE+7]]:8: error: unexpected error produced: could not build
+// CHECK: error: unexpected note produced: in file included from <module-includes>:1:
+// CHECK: note: file '<module-includes>' is not parsed for 'expected' statements. Use '-verify-additional-file <module-includes>' to enable, or '-verify-ignore-unrelated' to ignore diagnostics in this file
+// CHECK: error: unexpected error produced: expected function body after function declarator
+// CHECK: note: file '{{.*}}broken_c.h' is not parsed for 'expected' statements. Use '-verify-additional-file {{.*}}broken_c.h' to enable, or '-verify-ignore-unrelated' to ignore diagnostics in this file
+// CHECK: note: diagnostic produced elsewhere: in file included from <module-includes>
+// CHECK: broken_c.h:2:11: error: diagnostic produced elsewhere: expected function body after function declarator
+import BrokenCModule
diff --git a/test/Frontend/DiagnosticVerifier/expect-the-expected.swift b/test/Frontend/DiagnosticVerifier/expect-the-expected.swift
new file mode 100644
index 0000000000000..b026dfebf1806
--- /dev/null
+++ b/test/Frontend/DiagnosticVerifier/expect-the-expected.swift
@@ -0,0 +1,3 @@
+// RUN: %target-typecheck-verify-swift
+
+import Expected // expected-error {{no such module 'Expected'}}
diff --git a/test/Frontend/DiagnosticVerifier/fixits.swift b/test/Frontend/DiagnosticVerifier/fixits.swift
new file mode 100644
index 0000000000000..cb16c74ff32cd
--- /dev/null
+++ b/test/Frontend/DiagnosticVerifier/fixits.swift
@@ -0,0 +1,282 @@
+// Tests for fix-its on `-verify` mode.
+
+// RUN: not %target-typecheck-verify-swift 2>&1 | %FileCheck %s --implicit-check-not error: --implicit-check-not note: --implicit-check-not warning:
+
+func labeledFunc(aa: Int, bb: Int) {}
+
+func testNoneMarkerCheck() {
+  // CHECK: [[@LINE+2]]:78: error: expected no fix-its; actual fix-it seen: {{.*}}3-16=unlabeledFunc{{.*}}
+  // CHECK: [[@LINE+1]]:87: error: A second {{\{\{}}none}} was found. It may only appear once in an expectation.
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{none}} {{none}}
+
+  // CHECK: [[@LINE+1]]:134: error: {{\{\{}}none}} must be at the end.
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{none}} {{23-26=bb}}
+}
+
+func test0Fixits() {
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}}
+
+  // CHECK: [[@LINE+1]]:80: error: expected fix-it verification within braces; example: '1-2=text' or 'none'
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{}}
+
+  // CHECK: [[@LINE+1]]:81: error: expected line offset after leading '+' or '-' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+}}
+
+  // CHECK: [[@LINE+1]]:81: error: expected line offset after leading '+' or '-' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-}}
+
+  // CHECK: [[@LINE+1]]:81: error: expected '-' range separator in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected colon-separated column number after line offset in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-1}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected colon-separated column number after line offset in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:}}
+
+  // CHECK: [[@LINE+1]]:83: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:}}
+
+  // CHECK: [[@LINE+1]]:83: error: expected '-' range separator in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1}}
+
+  // CHECK: [[@LINE+1]]:84: error: expected '-' range separator in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-1:1}}
+
+  // CHECK: [[@LINE+1]]:83: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:-1}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected line or column number in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-}}
+
+  // CHECK: [[@LINE+1]]:84: error: expected line or column number in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-}}
+
+  // CHECK: [[@LINE+1]]:85: error: expected line or column number in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-1:1-}}
+
+  // CHECK: [[@LINE+1]]:83: error: expected line offset after leading '+' or '-' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1--}}
+
+  // CHECK: [[@LINE+1]]:83: error: expected '=' after range in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1}}
+
+  // CHECK: [[@LINE+1]]:85: error: expected '=' after range in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1}}
+
+  // CHECK: [[@LINE+1]]:86: error: expected '=' after range in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:1-1}}
+
+  // CHECK: [[@LINE+1]]:83: error: expected line offset after leading '+' or '-' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1--:}}
+
+  // CHECK: [[@LINE+1]]:84: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1:}}
+
+  // CHECK: [[@LINE+1]]:86: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1:}}
+
+  // CHECK: [[@LINE+1]]:87: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:1-1:}}
+
+  // CHECK: [[@LINE+1]]:85: error: expected '=' after range in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1:1}}
+
+  // CHECK: [[@LINE+1]]:86: error: expected '=' after range in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-+1:1}}
+
+  // CHECK: [[@LINE+1]]:87: error: expected '=' after range in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1:1}}
+
+  // CHECK: [[@LINE+1]]:89: error: expected '=' after range in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:1--1:1}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=a}}
+
+  // CHECK: [[@LINE+1]]:80: error: expected line or column number in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{x-1=a}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected line or column number in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-x=a}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:x-1=a}}
+
+  // CHECK: [[@LINE+1]]:80: error: expected line or column number in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{x:1-1=a}}
+
+  // CHECK: [[@LINE+1]]:81: error: expected line offset after leading '+' or '-' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+x:1-1=a}}
+
+  // CHECK: [[@LINE+1]]:84: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1:x=a}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected line or column number in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-x:1=a}}
+
+  // CHECK: [[@LINE+1]]:83: error: expected line offset after leading '+' or '-' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-+x:1=a}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:x-1:x=a}}
+
+  // CHECK: [[@LINE+1]]:80: error: expected line or column number in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{x:1-1:x=a}}
+
+  // CHECK: [[@LINE+1]]:81: error: expected line offset after leading '+' or '-' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+x:1-1:x=a}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:x-x:1=a}}
+
+  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:x--x:1=a}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1:1=a}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1:1=a}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1=a}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-1:1-1=a}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-+1:1=a}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:1-+1:1=a}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=a}} {{2-2=b}}
+
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{none}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=a}} {{none}}
+
+  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
+  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=a}} {{2-2=b}} {{none}}
+}
+
+func test1Fixits() {
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}}
+
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}}
+
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}}
+
+  // CHECK: [[@LINE+1]]:134: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{15-18=xx}}
+
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}} {{15-18=aa}}
+
+  // CHECK: [[@LINE+1]]:121: error: expected no fix-its; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{none}}
+
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{none}}
+
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}} {{none}}
+
+  // CHECK: [[@LINE+1]]:134: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{15-18=xx}} {{none}}
+
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}} {{15-18=aa}} {{none}}
+
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{201:15-201:18=aa}}
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{203:15-18=aa}}
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-205:18=aa}}
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{-0:15-+0:18=aa}}
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15--0:18=aa}}
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {+0:15-211:18=aa}}
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{+1:15-+1:18=bb}}
+              bbx: 1)
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{217:15-+1:18=bb}}
+              bbx: 1)
+
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{62:15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{-1:15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{+0:15--1:18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
+  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{62:15-+1:18=aa}}
+}
+
+// CHECK: [[@LINE+10]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+// CHECK: [[@LINE+9]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+// CHECK: [[@LINE+8]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+// CHECK: [[@LINE+7]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+// CHECK: [[@LINE+6]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+// CHECK: [[@LINE+5]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+// CHECK: [[@LINE+4]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+// CHECK: [[@LINE+3]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+// CHECK: [[@LINE+2]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+// CHECK: [[@LINE+1]]:6: error: unexpected note produced: 'unlabeledFunc' declared here
+func unlabeledFunc(_ aa: Int) {}
+
+func testDefaultedLineNumbers() {
+  // Fix-it end line defaults to first line.
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  unlabeledFunc(aa: // expected-error {{extraneous argument label 'aa:' in call}} {{+0:17-+1:5=}}
+    1)
+  // CHECK: [[@LINE+1]]:83: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}17-[[@LINE+2]]:5=}}
+  unlabeledFunc(aa: // expected-error {{extraneous argument label 'aa:' in call}} {{+0:17-5=}}
+    1)
+
+  // Fix-it start line defaults to diagnostic line.
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{+1:15-+1:18=bb}}
+              bbx: 1)
+  // CHECK: [[@LINE+1]]:113: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}[[@LINE+2]]:15-18=bb}}
+  labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{15-+1:18=bb}}
+              bbx: 1)
+}
+
+func test2Fixits() {
+  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}}
+
+  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}}
+
+  // CHECK: [[@LINE+1]]:124: error: expected fix-it not seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
+  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=xx}}
+
+  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=bb}}
+
+  // CHECK: [[@LINE+1]]:137: error: expected fix-it not seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
+  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=xx}}
+
+  // CHECK: [[@LINE+1]]:124: error: expected no fix-its; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
+  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{none}}
+
+  // CHECK: [[@LINE+1]]:137: error: unexpected fix-it seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
+  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{none}}
+
+  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=bb}} {{none}}
+
+  // CHECK: [[@LINE+1]]:137: error: expected fix-it not seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
+  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=xx}} {{none}}
+}
diff --git a/test/Frontend/DiagnosticVerifier/multiple_prefix_invalid.swift b/test/Frontend/DiagnosticVerifier/multiple_prefix_invalid.swift
new file mode 100644
index 0000000000000..6c48852b74c1b
--- /dev/null
+++ b/test/Frontend/DiagnosticVerifier/multiple_prefix_invalid.swift
@@ -0,0 +1,19 @@
+// RUN: not --crash %target-swift-frontend %s -verify -verify-additional-prefix first- -verify-additional-prefix first-second- -emit-sil -o /dev/null 2>&1 | %FileCheck %s --implicit-check-not error: --implicit-check-not note: --implicit-check-not warning:
+
+// This test makes sure that if we add prefixes such that an earlier prefix is a
+// prefix of a later prefix, we crash. We do this since the earlier prefix will
+// always succeed whenever the later prefix would succeed implying that this was
+// done through programmer error. So it is better to crash to indicate
+// programmer error rather than have the compiler author be confused.
+
+// CHECK: Error! Found a verifier diagnostic additional prefix that is a prefix of a later prefix. The later prefix will never be pattern matched!
+// CHECK: First Prefix: first-
+// CHECK: Second Prefix: first-second-
+// CHECK: <unknown>:0: error: fatal error encountered during compilation; please submit a bug report
+// CHECK: <unknown>:0: note: Standard compiler error!
+
+// CHECK: error:
+
+func test() {
+
+}
diff --git a/test/Frontend/diagnostic_verifier_multiple_prefix_negative.swift b/test/Frontend/DiagnosticVerifier/multiple_prefix_negative.swift
similarity index 100%
rename from test/Frontend/diagnostic_verifier_multiple_prefix_negative.swift
rename to test/Frontend/DiagnosticVerifier/multiple_prefix_negative.swift
diff --git a/test/Frontend/diagnostic_verifier_multiple_prefix_positive.swift b/test/Frontend/DiagnosticVerifier/multiple_prefix_positive.swift
similarity index 100%
rename from test/Frontend/diagnostic_verifier_multiple_prefix_positive.swift
rename to test/Frontend/DiagnosticVerifier/multiple_prefix_positive.swift
diff --git a/test/FixCode/verify-fixits.swift b/test/Frontend/DiagnosticVerifier/verify-apply-fixes.swift
similarity index 100%
rename from test/FixCode/verify-fixits.swift
rename to test/Frontend/DiagnosticVerifier/verify-apply-fixes.swift
diff --git a/test/FixCode/verify-fixits.swift.result b/test/Frontend/DiagnosticVerifier/verify-apply-fixes.swift.result
similarity index 100%
rename from test/FixCode/verify-fixits.swift.result
rename to test/Frontend/DiagnosticVerifier/verify-apply-fixes.swift.result
diff --git a/test/Frontend/verify.swift b/test/Frontend/DiagnosticVerifier/verify.swift
similarity index 75%
rename from test/Frontend/verify.swift
rename to test/Frontend/DiagnosticVerifier/verify.swift
index af37fc3d2bfe5..b62e44706f3f2 100644
--- a/test/Frontend/verify.swift
+++ b/test/Frontend/DiagnosticVerifier/verify.swift
@@ -1,6 +1,6 @@
 // Tests for the Swift frontends `-verify` mode.
 
-// RUN: not %target-typecheck-verify-swift 2>&1 | %FileCheck %s
+// RUN: not %target-typecheck-verify-swift 2>&1 | %FileCheck %s --implicit-check-not error: --implicit-check-not note: --implicit-check-not warning:
 
 // CHECK: [[@LINE+1]]:1: error: unexpected error produced: cannot find 'undefinedFunc' in scope
 undefinedFunc()
@@ -30,6 +30,8 @@ fn(())    // expected-error {{argument passed to call that takes no arguments}}
 // CHECK: [[@LINE+1]]:81: error: expected no fix-its; actual fix-it seen: {{[{][{]4-6=[}][}]}}
 fn(())    // expected-error {{argument passed to call that takes no arguments}} {{none}}
 
-// CHECK: [[@LINE+2]]:8: error: unexpected error produced: generic type 'Array' specialized with too many type parameters
-// CHECK: note: diagnostic produced elsewhere: generic type 'Array' declared here
+// CHECK: [[@LINE+1]]:8: error: unexpected error produced: generic type 'Array' specialized with too many type parameters
 let x: Array<Int, Int>
+// CHECK: error: unexpected note produced: generic struct 'Array' declared here
+// CHECK: note: file 'Swift.Array' is not parsed for 'expected' statements. Use '-verify-additional-file Swift.Array' to enable, or '-verify-ignore-unrelated' to ignore diagnostics in this file
+// CHECK: note: diagnostic produced elsewhere: generic struct 'Array' declared here
diff --git a/test/Frontend/DiagnosticVerifier/verify2.swift b/test/Frontend/DiagnosticVerifier/verify2.swift
new file mode 100644
index 0000000000000..ff3b23d6719e8
--- /dev/null
+++ b/test/Frontend/DiagnosticVerifier/verify2.swift
@@ -0,0 +1,50 @@
+// RUN: %empty-directory(%t)
+// RUN: not %target-swift-frontend -typecheck -verify -serialize-diagnostics-path %t/serialized.dia %s 2>&1 | %FileCheck %s --check-prefixes CHECK,CHECK-WARNINGS-AS-WARNINGS --implicit-check-not error: --implicit-check-not note: --implicit-check-not warning:
+// RUN: not %target-swift-frontend -typecheck -verify -warnings-as-errors %s 2>&1 | %FileCheck %s -check-prefixes CHECK,CHECK-WARNINGS-AS-ERRORS --implicit-check-not error: --implicit-check-not note: --implicit-check-not warning:
+// RUN: %FileCheck %s -check-prefix CHECK-SERIALIZED <%t/serialized.dia
+
+// Wrong message
+let x: Int = "hello, world!" // expected-error {{foo bar baz}}
+// CHECK-NOT: error: cannot convert value of type 'String' to specified type 'Int'
+// CHECK: [[@LINE-2]]:50: error: incorrect message found
+
+// Wrong column
+let y: Int = "hello, world!" // expected-error@:49 {{cannot convert value of type}}
+// CHECK: error: message found at column 14 but was expected to appear at column 49
+
+// Wrong fix-it
+let z: Int = "hello, world!" as Any
+// expected-error@-1 {{cannot convert value of type}} {{3-3=foobarbaz}}
+// CHECK: error: expected fix-it not seen; actual fix-it seen: {{[{][{]}}36-36= as! Int{{[}][}]}}
+
+// Expected no fix-it
+let a: Bool = "hello, world!" as Any
+// expected-error@-1 {{cannot convert value of type}} {{none}}
+// CHECK: error: expected no fix-its; actual fix-it seen: {{[{][{]}}37-37= as! Bool{{[}][}]}}
+
+// Unexpected error
+_ = foo()
+// CHECK: error: unexpected error produced: cannot find 'foo' in scope
+
+func b() {
+  let c = 2
+}
+// CHECK-WARNINGS-AS-WARNINGS: error: unexpected warning produced: initialization of immutable value 'c' was never used
+// CHECK-WARNINGS-AS-ERRORS: error: unexpected error produced: initialization of immutable value 'c' was never used
+
+typealias Crap = () -> ()
+extension Crap {} // expected-error {{non-nominal type 'Crap' (aka '() -> ()') cannot be extended}} {{documentation-file=foo-bar-baz}}
+// CHECK: error: expected documentation file not seen; actual documentation file: {{[{][{]}}documentation-file=nominal-types{{[}][}]}}
+
+extension Crap {} // expected-error {{non-nominal type 'Crap' (aka '() -> ()') cannot be extended}} {{documentation-file=nominal-types}} {{documentation-file=nominal-types}}
+// CHECK: error: each verified diagnostic may only have one {{[{][{]}}documentation-file=<#notes#>{{[}][}]}} declaration
+
+extension Crap {} // expected-error {{non-nominal type 'Crap' (aka '() -> ()') cannot be extended}} {{documentation-file=nominal-types,foo-bar-baz}}
+// CHECK: error: expected documentation file not seen; actual documentation file: {{[{][{]}}documentation-file=nominal-types{{[}][}]}}
+
+// CHECK: error: unexpected note produced: 'Bool' declared here
+// CHECK: note: file 'Swift.Bool' is not parsed for 'expected' statements. Use '-verify-additional-file Swift.Bool' to enable, or '-verify-ignore-unrelated' to ignore diagnostics in this file
+// CHECK: note: diagnostic produced elsewhere: 'Bool' declared here
+
+// Verify the serialized diags have the right magic at the top.
+// CHECK-SERIALIZED: DIA
diff --git a/test/Frontend/Inputs/opt-record-2.swift b/test/Frontend/Inputs/opt-record-2.swift
new file mode 100644
index 0000000000000..b086032300888
--- /dev/null
+++ b/test/Frontend/Inputs/opt-record-2.swift
@@ -0,0 +1,24 @@
+open class C {
+    var x = 1
+    var y = 2
+
+    public init() {
+    }
+
+    public func method() {
+        print("x: \(x)")
+    }
+
+    public func method2() {
+        print("x2: \(y)")
+    }
+}
+
+@_assemblyVision
+@inline(never)
+public func runSomeTest(_ c: C) {
+  for i in 0..<100 {
+    c.method()
+    c.method2()
+  }
+}
diff --git a/test/Frontend/OptimizationOptions-with-stdlib-checks.swift b/test/Frontend/OptimizationOptions-with-stdlib-checks.swift
index d7c3c78596c19..4c2c4eca76b85 100644
--- a/test/Frontend/OptimizationOptions-with-stdlib-checks.swift
+++ b/test/Frontend/OptimizationOptions-with-stdlib-checks.swift
@@ -104,8 +104,7 @@ func test_partial_safety_check(x: Int, y: Int) -> Int {
 // In release mode keep succinct library precondition checks (trap).
 // RELEASE-LABEL: sil hidden @$s19OptimizationOptions22testprecondition_check1x1yS2i_SitF : $@convention(thin) (Int, Int) -> Int {
 // RELEASE-NOT:  "Fatal error"
-// RELEASE:  %[[V2:.+]] = builtin "xor_Int1"(%{{.+}}, %{{.+}})
-// RELEASE:  cond_fail %[[V2]]
+// RELEASE:  cond_fail %{{[0-9]}}, "precondition failure"
 // RELEASE:  return
 
 // In unchecked mode remove library precondition checks.
diff --git a/test/Frontend/OptimizationOptions-without-stdlib-checks.swift b/test/Frontend/OptimizationOptions-without-stdlib-checks.swift
index c51ab8a7834c4..989cdf53af21b 100644
--- a/test/Frontend/OptimizationOptions-without-stdlib-checks.swift
+++ b/test/Frontend/OptimizationOptions-without-stdlib-checks.swift
@@ -101,8 +101,7 @@ func test_partial_safety_check(x: Int, y: Int) -> Int {
 // In release mode keep succinct library precondition checks (trap).
 // RELEASE-LABEL: sil hidden @$s19OptimizationOptions22testprecondition_check1x1yS2i_SitF : $@convention(thin) (Int, Int) -> Int {
 // RELEASE-NOT:  "Fatal error"
-// RELEASE:  %[[V2:.+]] = builtin "xor_Int1"(%{{.+}}, %{{.+}})
-// RELEASE:  cond_fail %[[V2]]
+// RELEASE:  cond_fail %{{[0-9]}}, "precondition failure"
 // RELEASE:  return
 
 // In unchecked mode remove library precondition checks.
diff --git a/test/Frontend/ast-dump-json-no-crash.swift b/test/Frontend/ast-dump-json-no-crash.swift
index bfa739dd27256..d7bc2a052ef16 100644
--- a/test/Frontend/ast-dump-json-no-crash.swift
+++ b/test/Frontend/ast-dump-json-no-crash.swift
@@ -263,6 +263,13 @@ func sb3() {
     }
 }
 
+func nestedOpaques0() -> some BinaryInteger { 2 }
+func nestedOpaques1() -> some FixedWidthInteger & SignedInteger { 2 }
+func nestedOpaques2() -> (some BinaryInteger, some Sequence) { (2, []) }
+func nestedOpaques3() -> (some BinaryInteger, some Sequence<Double>) { (2, []) }
+func nestedOpaques4() -> (some BinaryInteger)? { Bool.random() ? 2 : nil }
+func nestedOpaques5() -> [some BinaryInteger] { [2] }
+
 // Expressions
 
 func zz1() throws {
@@ -341,9 +348,8 @@ struct Pack<each T> {
     func f(_ t: repeat each T) {
         repeat g(each t)
     }
+    func g<U>(_ t: U) {}
 }
-// FIXME: USR generation crashes if this is a member of Pack<each T> above!
-func g<U>(_ t: U) {}
 
 func tuplify<each T>(_ value: repeat each T) -> (repeat each T) {
   return (repeat each value)
@@ -353,6 +359,17 @@ func example<each T>(_ value: repeat each T) {
   repeat print(each abstractTuple)
 }
 
+func anySeq<T>(_ type: T.Type = T.self) -> any Sequence<T> { [] }
+func anySeqUser() {
+    let s = anySeq(Int.self)
+    let iter = s.makeIterator()
+}
+func opaqueSeq<T>(_ type: T.Type = T.self) -> some Sequence<T> { [] }
+func opaqueSeqUser() {
+    let s = opaqueSeq(Int.self)
+    let iter = s.makeIterator()
+}
+
 let x = 10
 func zz1b() {
     _ = type(of: x)
diff --git a/test/Frontend/debug-generic-signatures.swift b/test/Frontend/debug-generic-signatures.swift
index 0fca2d1c0ce0a..ff6af2a3bbbf2 100644
--- a/test/Frontend/debug-generic-signatures.swift
+++ b/test/Frontend/debug-generic-signatures.swift
@@ -34,19 +34,19 @@ struct Basic: P1 {
 // Recursive conformances should have finite output.
 
 // CHECK-LABEL: StructDecl name=Recur
-// CHECK-NEXT: (builtin_conformance type="Recur" protocol="Copyable")
-// CHECK-NEXT: (builtin_conformance type="Recur" protocol="Escapable")
+// CHECK-NEXT: (builtin_conformance type="Recur" protocol="Copyable"{{.*}})
+// CHECK-NEXT: (builtin_conformance type="Recur" protocol="Escapable"{{.*}})
 // CHECK-NEXT: (normal_conformance type="Recur" protocol="P2"
 // CHECK-NEXT:   (assoc_type req="A" type="Recur")
 // CHECK-NEXT:   (assoc_type req="B" type="Recur")
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:     (builtin_conformance type="Recur" protocol="Copyable"))
+// CHECK-NEXT:     (builtin_conformance type="Recur" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:     (builtin_conformance type="Recur" protocol="Escapable"))
+// CHECK-NEXT:     (builtin_conformance type="Recur" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="P2"
-// CHECK-NEXT:     (normal_conformance type="Recur" protocol="P2" <details printed above>))
+// CHECK-NEXT:     (normal_conformance type="Recur" protocol="P2"{{.*}} <details printed above>))
 // CHECK-NEXT:   (assoc_conformance type="Self.B" proto="P2"
-// CHECK-NEXT:     (normal_conformance type="Recur" protocol="P2" <details printed above>)))
+// CHECK-NEXT:     (normal_conformance type="Recur" protocol="P2"{{.*}} <details printed above>)))
 struct Recur: P2 {
     typealias A = Recur
     typealias B = Recur
@@ -55,29 +55,29 @@ struct Recur: P2 {
 // The full information about a conformance doesn't need to be printed twice.
 
 // CHECK-LABEL: StructDecl name=NonRecur
-// CHECK-NEXT: (builtin_conformance type="NonRecur" protocol="Copyable")
-// CHECK-NEXT: (builtin_conformance type="NonRecur" protocol="Escapable")
+// CHECK-NEXT: (builtin_conformance type="NonRecur" protocol="Copyable"{{.*}})
+// CHECK-NEXT: (builtin_conformance type="NonRecur" protocol="Escapable"{{.*}})
 // CHECK-NEXT: (normal_conformance type="NonRecur" protocol="P2"
 // CHECK-NEXT:   (assoc_type req="A" type="Recur")
 // CHECK-NEXT:   (assoc_type req="B" type="Recur")
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:     (builtin_conformance type="NonRecur" protocol="Copyable"))
+// CHECK-NEXT:     (builtin_conformance type="NonRecur" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:     (builtin_conformance type="NonRecur" protocol="Escapable"))
+// CHECK-NEXT:     (builtin_conformance type="NonRecur" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="P2"
 // CHECK-NEXT:     (normal_conformance type="Recur" protocol="P2"
 // CHECK-NEXT:       (assoc_type req="A" type="Recur")
 // CHECK-NEXT:       (assoc_type req="B" type="Recur")
 // CHECK-NEXT:       (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:         (builtin_conformance type="Recur" protocol="Copyable"))
+// CHECK-NEXT:         (builtin_conformance type="Recur" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:       (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:         (builtin_conformance type="Recur" protocol="Escapable"))
+// CHECK-NEXT:         (builtin_conformance type="Recur" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:       (assoc_conformance type="Self.A" proto="P2"
-// CHECK-NEXT:         (normal_conformance type="Recur" protocol="P2" <details printed above>))
+// CHECK-NEXT:         (normal_conformance type="Recur" protocol="P2"{{.*}} <details printed above>))
 // CHECK-NEXT:       (assoc_conformance type="Self.B" proto="P2"
-// CHECK-NEXT:         (normal_conformance type="Recur" protocol="P2" <details printed above>))))
+// CHECK-NEXT:         (normal_conformance type="Recur" protocol="P2"{{.*}} <details printed above>))))
 // CHECK-NEXT:   (assoc_conformance type="Self.B" proto="P2"
-// CHECK-NEXT:     (normal_conformance type="Recur" protocol="P2" <details printed above>)))
+// CHECK-NEXT:     (normal_conformance type="Recur" protocol="P2"{{.*}} <details printed above>)))
 struct NonRecur: P2 {
     typealias A = Recur
     typealias B = Recur
@@ -94,9 +94,9 @@ struct Generic<T> {}
 // CHECK-NEXT:   (assoc_type req="A" type="T")
 // CHECK-NEXT:   (value req="f()" witness="main.(file).Generic extension.f()@{{.*}}")
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:     (builtin_conformance type="Generic<T>" protocol="Copyable"))
+// CHECK-NEXT:     (builtin_conformance type="Generic<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:     (builtin_conformance type="Generic<T>" protocol="Escapable"))
+// CHECK-NEXT:     (builtin_conformance type="Generic<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="Copyable"
 // CHECK-NEXT:     (abstract_conformance type="T" protocol="Copyable"))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="Escapable"
@@ -119,9 +119,9 @@ class Super<T, U> {}
 // CHECK-NEXT:   (assoc_type req="A" type="T")
 // CHECK-NEXT:   (assoc_type req="B" type="T")
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:     (builtin_conformance type="Super<T, U>" protocol="Copyable"))
+// CHECK-NEXT:     (builtin_conformance type="Super<T, U>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:     (builtin_conformance type="Super<T, U>" protocol="Escapable"))
+// CHECK-NEXT:     (builtin_conformance type="Super<T, U>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="P2"
 // CHECK-NEXT:     (abstract_conformance type="T" protocol="P2"))
 // CHECK-NEXT:   (assoc_conformance type="Self.B" proto="P2"
@@ -135,8 +135,8 @@ extension Super: P2 where T: P2, U: P2 {
 
 // Inherited/specialized conformances.
 // CHECK-LABEL: ClassDecl name=Sub
-// CHECK-NEXT: (builtin_conformance type="Sub" protocol="Copyable")
-// CHECK-NEXT: (builtin_conformance type="Sub" protocol="Escapable")
+// CHECK-NEXT: (builtin_conformance type="Sub" protocol="Copyable"{{.*}})
+// CHECK-NEXT: (builtin_conformance type="Sub" protocol="Escapable"{{.*}})
 // CHECK-NEXT: (inherited_conformance type="Sub" protocol="P2"
 // CHECK-NEXT:   (specialized_conformance type="Super<NonRecur, Recur>" protocol="P2"
 // CHECK-NEXT:     (substitution_map generic_signature=<T, U where T : P2, U : P2>
@@ -149,33 +149,33 @@ extension Super: P2 where T: P2, U: P2 {
 // CHECK-NEXT:           (assoc_type req="A" type="Recur")
 // CHECK-NEXT:           (assoc_type req="B" type="Recur")
 // CHECK-NEXT:           (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:             (builtin_conformance type="NonRecur" protocol="Copyable"))
+// CHECK-NEXT:             (builtin_conformance type="NonRecur" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:           (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:             (builtin_conformance type="NonRecur" protocol="Escapable"))
+// CHECK-NEXT:             (builtin_conformance type="NonRecur" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:           (assoc_conformance type="Self.A" proto="P2"
 // CHECK-NEXT:             (normal_conformance type="Recur" protocol="P2"
 // CHECK-NEXT:               (assoc_type req="A" type="Recur")
 // CHECK-NEXT:               (assoc_type req="B" type="Recur")
 // CHECK-NEXT:               (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:                 (builtin_conformance type="Recur" protocol="Copyable"))
+// CHECK-NEXT:                 (builtin_conformance type="Recur" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:               (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:                 (builtin_conformance type="Recur" protocol="Escapable"))
+// CHECK-NEXT:                 (builtin_conformance type="Recur" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:               (assoc_conformance type="Self.A" proto="P2"
-// CHECK-NEXT:                 (normal_conformance type="Recur" protocol="P2" <details printed above>))
+// CHECK-NEXT:                 (normal_conformance type="Recur" protocol="P2"{{.*}} <details printed above>))
 // CHECK-NEXT:               (assoc_conformance type="Self.B" proto="P2"
-// CHECK-NEXT:                 (normal_conformance type="Recur" protocol="P2" <details printed above>))))
+// CHECK-NEXT:                 (normal_conformance type="Recur" protocol="P2"{{.*}} <details printed above>))))
 // CHECK-NEXT:           (assoc_conformance type="Self.B" proto="P2"
-// CHECK-NEXT:             (normal_conformance type="Recur" protocol="P2" <details printed above>))))
+// CHECK-NEXT:             (normal_conformance type="Recur" protocol="P2"{{.*}} <details printed above>))))
 // CHECK-NEXT:       (conformance type="U"
-// CHECK-NEXT:         (normal_conformance type="Recur" protocol="P2" <details printed above>)))
+// CHECK-NEXT:         (normal_conformance type="Recur" protocol="P2"{{.*}} <details printed above>)))
 // CHECK-NEXT:     (<conditional requirements unable to be computed>)
 // CHECK-NEXT:     (normal_conformance type="Super<T, U>" protocol="P2"
 // CHECK-NEXT:       (assoc_type req="A" type="T")
 // CHECK-NEXT:       (assoc_type req="B" type="T")
 // CHECK-NEXT:       (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:         (builtin_conformance type="Super<T, U>" protocol="Copyable"))
+// CHECK-NEXT:         (builtin_conformance type="Super<T, U>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:       (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:         (builtin_conformance type="Super<T, U>" protocol="Escapable"))
+// CHECK-NEXT:         (builtin_conformance type="Super<T, U>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:       (assoc_conformance type="Self.A" proto="P2"
 // CHECK-NEXT:         (abstract_conformance type="T" protocol="P2"))
 // CHECK-NEXT:       (assoc_conformance type="Self.B" proto="P2"
@@ -188,44 +188,44 @@ class Sub: Super<NonRecur, Recur> {}
 // should work through SubstitutionMaps.
 
 // CHECK-LABEL: StructDecl name=RecurGeneric
-// CHECK-NEXT: (builtin_conformance type="RecurGeneric<T>" protocol="Copyable")
-// CHECK-NEXT: (builtin_conformance type="RecurGeneric<T>" protocol="Escapable")
+// CHECK-NEXT: (builtin_conformance type="RecurGeneric<T>" protocol="Copyable"{{.*}})
+// CHECK-NEXT: (builtin_conformance type="RecurGeneric<T>" protocol="Escapable"{{.*}})
 // CHECK-NEXT: (normal_conformance type="RecurGeneric<T>" protocol="P3"
 // CHECK-NEXT:   (assoc_type req="A" type="RecurGeneric<T>")
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:     (builtin_conformance type="RecurGeneric<T>" protocol="Copyable"))
+// CHECK-NEXT:     (builtin_conformance type="RecurGeneric<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:     (builtin_conformance type="RecurGeneric<T>" protocol="Escapable"))
+// CHECK-NEXT:     (builtin_conformance type="RecurGeneric<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="P3"
-// CHECK-NEXT:     (normal_conformance type="RecurGeneric<T>" protocol="P3" <details printed above>)))
+// CHECK-NEXT:     (normal_conformance type="RecurGeneric<T>" protocol="P3"{{.*}} <details printed above>)))
 struct RecurGeneric<T: P3>: P3 {
     typealias A = RecurGeneric<T>
 }
 
 // CHECK-LABEL: StructDecl name=Specialize
-// CHECK-NEXT: (builtin_conformance type="Specialize" protocol="Copyable")
-// CHECK-NEXT: (builtin_conformance type="Specialize" protocol="Escapable")
+// CHECK-NEXT: (builtin_conformance type="Specialize" protocol="Copyable"{{.*}})
+// CHECK-NEXT: (builtin_conformance type="Specialize" protocol="Escapable"{{.*}})
 // CHECK-NEXT: (normal_conformance type="Specialize" protocol="P3"
 // CHECK-NEXT:   (assoc_type req="A" type="RecurGeneric<Specialize>")
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:     (builtin_conformance type="Specialize" protocol="Copyable"))
+// CHECK-NEXT:     (builtin_conformance type="Specialize" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:     (builtin_conformance type="Specialize" protocol="Escapable"))
+// CHECK-NEXT:     (builtin_conformance type="Specialize" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="P3"
 // CHECK-NEXT:     (specialized_conformance type="Specialize.A" protocol="P3"
 // CHECK-NEXT:       (substitution_map generic_signature=<T where T : P3>
 // CHECK-NEXT:         (substitution T ->
 // CHECK-NEXT:           (struct_type decl="main.(file).Specialize@{{.*}}"))
 // CHECK-NEXT:         (conformance type="T"
-// CHECK-NEXT:           (normal_conformance type="Specialize" protocol="P3" <details printed above>)))
+// CHECK-NEXT:           (normal_conformance type="Specialize" protocol="P3"{{.*}} <details printed above>)))
 // CHECK-NEXT:       (normal_conformance type="RecurGeneric<T>" protocol="P3"
 // CHECK-NEXT:         (assoc_type req="A" type="RecurGeneric<T>")
 // CHECK-NEXT:         (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:           (builtin_conformance type="RecurGeneric<T>" protocol="Copyable"))
+// CHECK-NEXT:           (builtin_conformance type="RecurGeneric<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:         (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:           (builtin_conformance type="RecurGeneric<T>" protocol="Escapable"))
+// CHECK-NEXT:           (builtin_conformance type="RecurGeneric<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:         (assoc_conformance type="Self.A" proto="P3"
-// CHECK-NEXT:           (normal_conformance type="RecurGeneric<T>" protocol="P3" <details printed above>))))))
+// CHECK-NEXT:           (normal_conformance type="RecurGeneric<T>" protocol="P3"{{.*}} <details printed above>))))))
 struct Specialize: P3 {
     typealias A = RecurGeneric<Specialize>
 }
diff --git a/test/Frontend/default-search-paths.swift b/test/Frontend/default-search-paths.swift
new file mode 100644
index 0000000000000..d626bd1506b23
--- /dev/null
+++ b/test/Frontend/default-search-paths.swift
@@ -0,0 +1,43 @@
+// UNSUPPORTED: OS=windows-msvc
+
+// Standard Apple paths.
+// RUN: %swift_frontend_plain -target arm64-apple-macos15.4 %clang-importer-sdk-nosource -parse-stdlib -parse %s -Rmodule-loading 2>&1 | %FileCheck -check-prefix=APPLE %s
+// APPLE: Implicit framework search paths:
+// APPLE-NEXT: [0] SOURCE_DIR/test/Inputs/clang-importer-sdk/System/Library/Frameworks
+// APPLE-NEXT: [1] SOURCE_DIR/test/Inputs/clang-importer-sdk/System/Library/SubFrameworks
+// APPLE-NEXT: [2] SOURCE_DIR/test/Inputs/clang-importer-sdk/Library/Frameworks
+// APPLE-NEXT: Runtime library import search paths:
+// APPLE-NEXT: [0] BUILD_DIR/lib/swift/macosx
+// APPLE-NEXT: [1] SOURCE_DIR/test/Inputs/clang-importer-sdk/usr/lib/swift
+// APPLE-NEXT: (End of search path lists.)
+
+// Non-Apple platforms don't have any implicit framework search paths.
+// RUN: %swift_frontend_plain -target x86_64-unknown-linux-android %clang-importer-sdk-nosource -parse-stdlib -parse %s -Rmodule-loading 2>&1 | %FileCheck -check-prefix=ANDROID %s
+// ANDROID: Implicit framework search paths:
+// ANDROID-NEXT: Runtime library import search paths:
+// ANDROID-NEXT: [0] BUILD_DIR/lib/swift/android
+// ANDROID-NEXT: [1] BUILD_DIR/lib/swift/android/x86_64
+// ANDROID-NEXT: [2] SOURCE_DIR/test/Inputs/clang-importer-sdk/usr/lib/swift/android
+// ANDROID-NEXT: [3] SOURCE_DIR/test/Inputs/clang-importer-sdk/usr/lib/swift/android/x86_64
+// ANDROID-NEXT: (End of search path lists.)
+
+// -nostdimport doesn't set up any standard import paths at all.
+// RUN: %swift_frontend_plain -target arm64-apple-macos15.4 %clang-importer-sdk-nosource -parse-stdlib -nostdimport -parse %s -Rmodule-loading 2>&1 | %FileCheck -check-prefix=NOSTDIMPORT %s
+// RUN: %swift_frontend_plain -target x86_64-unknown-linux-android %clang-importer-sdk-nosource -parse-stdlib -nostdimport -parse %s -Rmodule-loading 2>&1 | %FileCheck -check-prefix=NOSTDIMPORT %s
+// NOSTDIMPORT: Implicit framework search paths:
+// NOSTDIMPORT-NEXT: Runtime library import search paths:
+// NOSTDIMPORT-NEXT: (End of search path lists.)
+
+// -nostdlibimport removes all of the standard imports from the SDK but leaves the toolchain ones.
+// RUN: %swift_frontend_plain -target arm64-apple-macos15.4 %clang-importer-sdk-nosource -parse-stdlib -nostdlibimport -parse %s -Rmodule-loading 2>&1 | %FileCheck -check-prefix=APPLE-NOSTDLIBIMPORT %s
+// APPLE-NOSTDLIBIMPORT: Implicit framework search paths:
+// APPLE-NOSTDLIBIMPORT-NEXT: Runtime library import search paths:
+// APPLE-NOSTDLIBIMPORT-NEXT: [0] BUILD_DIR/lib/swift/macosx
+// APPLE-NOSTDLIBIMPORT-NEXT: (End of search path lists.)
+
+// RUN: %swift_frontend_plain -target x86_64-unknown-linux-android %clang-importer-sdk-nosource -parse-stdlib -nostdlibimport -parse %s -Rmodule-loading 2>&1 | %FileCheck -check-prefix=ANDROID-NOSTDLIBIMPORT %s
+// ANDROID-NOSTDLIBIMPORT: Implicit framework search paths:
+// ANDROID-NOSTDLIBIMPORT-NEXT: Runtime library import search paths:
+// ANDROID-NOSTDLIBIMPORT-NEXT: [0] BUILD_DIR/lib/swift/android
+// ANDROID-NOSTDLIBIMPORT-NEXT: [1] BUILD_DIR/lib/swift/android/x86_64
+// ANDROID-NOSTDLIBIMPORT-NEXT: (End of search path lists.)
diff --git a/test/Frontend/diagnostic_verifier_multiple_prefix_invalid.swift b/test/Frontend/diagnostic_verifier_multiple_prefix_invalid.swift
deleted file mode 100644
index 47135557f5e19..0000000000000
--- a/test/Frontend/diagnostic_verifier_multiple_prefix_invalid.swift
+++ /dev/null
@@ -1,15 +0,0 @@
-// RUN: not --crash %target-swift-frontend %s -verify -verify-additional-prefix first- -verify-additional-prefix first-second- -emit-sil -o /dev/null 2>&1 | %FileCheck %s
-
-// This test makes sure that if we add prefixes such that an earlier prefix is a
-// prefix of a later prefix, we crash. We do this since the earlier prefix will
-// always succeed whenever the later prefix would succeed implying that this was
-// done through programmer error. So it is better to crash to indicate
-// programmer error rather than have the compiler author be confused.
-
-// CHECK: Error! Found a verifier diagnostic additional prefix that is a prefix of a later prefix. The later prefix will never be pattern matched!
-// CHECK: First Prefix: first-
-// CHECK: Second Prefix: first-second-
-
-func test() {
-
-}
diff --git a/test/Frontend/dynamic_member_lookup_limit.swift b/test/Frontend/dynamic_member_lookup_limit.swift
new file mode 100644
index 0000000000000..1b8103c7d8053
--- /dev/null
+++ b/test/Frontend/dynamic_member_lookup_limit.swift
@@ -0,0 +1,21 @@
+// RUN: %target-typecheck-verify-swift -dynamic-member-lookup-depth-limit=2
+
+@dynamicMemberLookup
+struct Lens<T> {
+  init() {}
+  subscript<U>(dynamicMember kp: KeyPath<T, U>) -> U {
+    fatalError()
+  }
+}
+
+struct S {
+  var x: Int
+}
+
+_ = \Lens<S>.x // Fine
+_ = \Lens<Lens<S>>.x // Also fine
+_ = \Lens<Lens<Lens<S>>>.x // expected-error {{could not find member 'x'; exceeded the maximum number of nested dynamic member lookups}}
+
+_ = Lens<S>().x // Fine
+_ = Lens<Lens<S>>().x // Also fine
+_ = Lens<Lens<Lens<S>>>().x // expected-error {{could not find member 'x'; exceeded the maximum number of nested dynamic member lookups}}
diff --git a/test/Frontend/embed-bitcode.swift b/test/Frontend/embed-bitcode.swift
index 9f59002b56109..e16c7b7180e5f 100644
--- a/test/Frontend/embed-bitcode.swift
+++ b/test/Frontend/embed-bitcode.swift
@@ -1,16 +1,8 @@
-// REQUIRES: CPU=x86_64
+// REQUIRES: OS=macosx || OS=ios || OS=tvos || OS=watchos, CPU=x86_64
 // RUN: %target-swift-frontend -c -module-name someModule -embed-bitcode-marker  -o %t.o %s
 // RUN: llvm-objdump --macho --section="__LLVM,__bitcode" %t.o | %FileCheck -check-prefix=MARKER %s
 // RUN: llvm-objdump --macho --section="__LLVM,__swift_cmdline" %t.o | %FileCheck -check-prefix=MARKER-CMD %s
 
-// This file tests Mach-O file output, but Linux variants do not produce Mach-O
-// files.
-// UNSUPPORTED: OS=linux-gnu
-// UNSUPPORTED: OS=linux-gnueabihf
-// UNSUPPORTED: OS=freebsd
-// UNSUPPORTED: OS=openbsd
-// UNSUPPORTED: OS=windows-msvc
-
 // MARKER: Contents of (__LLVM,__bitcode) section
 // MARKER-NEXT: 00
 // MARKER-CMD: Contents of (__LLVM,__swift_cmdline) section
diff --git a/test/Frontend/emit-supported-features.swift b/test/Frontend/emit-supported-features.swift
deleted file mode 100644
index c5be4212b1711..0000000000000
--- a/test/Frontend/emit-supported-features.swift
+++ /dev/null
@@ -1,8 +0,0 @@
-// RUN: %target-swift-frontend -emit-supported-features %s | %FileCheck %s
-
-// CHECK: "SupportedArguments"
-// CHECK: "abi"
-// CHECK: "emit-module"
-// CHECK: "LastOption"
-// CHECK: "SupportedFeatures"
-// CHECK: "LastFeature"
diff --git a/test/Frontend/explicit-swift-module-map-file-parser.swift b/test/Frontend/explicit-swift-module-map-file-parser.swift
new file mode 100644
index 0000000000000..3297ae88f0076
--- /dev/null
+++ b/test/Frontend/explicit-swift-module-map-file-parser.swift
@@ -0,0 +1,78 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: not %target-swift-frontend -typecheck %t/test.swift \
+// RUN:   -explicit-swift-module-map-file %t/invalid_root_object.json \
+// RUN:   2>&1 | %FileCheck %s -check-prefix=CHECK-ROOT
+
+// CHECK-ROOT: malformed: invalid JSON root object
+
+// RUN: not %target-swift-frontend -typecheck %t/test.swift \
+// RUN:   -explicit-swift-module-map-file %t/invalid_entry_type.json \
+// RUN:   2>&1 | %FileCheck %s -check-prefix=CHECK-ENTRY-TYPE
+
+// CHECK-ENTRY-TYPE: malformed: incorrect entry type
+
+// RUN: not %target-swift-frontend -typecheck %t/test.swift \
+// RUN:   -explicit-swift-module-map-file %t/missing_module_name.json \
+// RUN:   2>&1 | %FileCheck %s -check-prefix=CHECK-NAME
+
+// CHECK-NAME: malformed: entry is missing module name
+
+// RUN: not %target-swift-frontend -typecheck %t/test.swift \
+// RUN:   -explicit-swift-module-map-file %t/duplicate_swift_module.json \
+// RUN:   2>&1 | %FileCheck %s -check-prefix=CHECK-DUP-SWIFT
+
+// CHECK-DUP-SWIFT: malformed: duplicate Swift module with name SwiftMod
+
+// RUN: not %target-swift-frontend -typecheck %t/test.swift \
+// RUN:   -explicit-swift-module-map-file %t/duplicate_clang_module.json \
+// RUN:   2>&1 | %FileCheck %s -check-prefix=CHECK-DUP-CLANG
+
+// CHECK-DUP-CLANG: malformed: duplicate Clang module with name ClangMod
+
+//--- invalid_root_object.json
+{
+    "some_key": "some_val"
+}
+//--- invalid_entry_type.json
+[
+    [
+        {"some_key": "some_val"}
+    ]
+]
+//--- missing_module_name.json
+[
+    {
+        "isFramework": false,
+        "modulePath": "/some/path"
+    }
+]
+//--- duplicate_swift_module.json
+[
+    {
+        "isFramework": false,
+        "moduleName": "SwiftMod",
+        "modulePath": "/some/path"
+    },
+    {
+        "isFramework": false,
+        "moduleName": "SwiftMod",
+        "modulePath": "/some/path"
+    }
+]
+//--- duplicate_clang_module.json
+[
+    {
+        "isFramework": false,
+        "moduleName": "ClangMod",
+        "clangModulePath": "/some/path"
+    },
+    {
+        "isFramework": false,
+        "moduleName": "ClangMod",
+        "clangModulePath": "/some/path"
+    }
+]
+//--- test.swift
+import Swift
diff --git a/test/Frontend/features/adoption_mode.swift b/test/Frontend/features/adoption_mode.swift
index 5cd437b1a6b21..f5f294e7e6ed9 100644
--- a/test/Frontend/features/adoption_mode.swift
+++ b/test/Frontend/features/adoption_mode.swift
@@ -4,29 +4,29 @@
 // RUN: %target-swift-frontend -parse -swift-version 5                         \
 // RUN:   -enable-upcoming-feature      DynamicActorIsolation:invalid1         \
 // RUN:   -enable-upcoming-feature      DynamicActorIsolation:invalid2         \
-// RUN:   -enable-upcoming-feature      DynamicActorIsolation:adoption         \
-// RUN:   -enable-upcoming-feature      DynamicActorIsolation:adoption         \
+// RUN:   -enable-upcoming-feature      DynamicActorIsolation:migrate         \
+// RUN:   -enable-upcoming-feature      DynamicActorIsolation:migrate         \
 // RUN:   -enable-experimental-feature  DynamicActorIsolation:invalid3         \
 // RUN:   -enable-experimental-feature  DynamicActorIsolation:invalid4         \
-// RUN:   -enable-experimental-feature  DynamicActorIsolation:adoption         \
-// RUN:   -enable-experimental-feature  DynamicActorIsolation:adoption         \
+// RUN:   -enable-experimental-feature  DynamicActorIsolation:migrate         \
+// RUN:   -enable-experimental-feature  DynamicActorIsolation:migrate         \
 // RUN:   -disable-upcoming-feature     DynamicActorIsolation:invalid5         \
 // RUN:   -disable-upcoming-feature     DynamicActorIsolation:invalid6         \
-// RUN:   -disable-upcoming-feature     DynamicActorIsolation:adoption         \
+// RUN:   -disable-upcoming-feature     DynamicActorIsolation:migrate         \
 // RUN:   -disable-experimental-feature DynamicActorIsolation:invalid7         \
 // RUN:   -disable-experimental-feature DynamicActorIsolation:invalid8         \
-// RUN:   -disable-experimental-feature DynamicActorIsolation:adoption         \
+// RUN:   -disable-experimental-feature DynamicActorIsolation:migrate         \
 // RUN:   %s 2>&1 | %FileCheck %s --check-prefix=CHECK-SWIFT-5
 
 // RUN: %target-swift-frontend -parse -swift-version 6                         \
 // RUN:   -enable-upcoming-feature      DynamicActorIsolation:invalid1         \
-// RUN:   -enable-upcoming-feature      DynamicActorIsolation:adoption         \
+// RUN:   -enable-upcoming-feature      DynamicActorIsolation:migrate         \
 // RUN:   -enable-experimental-feature  DynamicActorIsolation:invalid2         \
-// RUN:   -enable-experimental-feature  DynamicActorIsolation:adoption         \
+// RUN:   -enable-experimental-feature  DynamicActorIsolation:migrate         \
 // RUN:   -disable-upcoming-feature     DynamicActorIsolation:invalid3         \
-// RUN:   -disable-upcoming-feature     DynamicActorIsolation:adoption         \
+// RUN:   -disable-upcoming-feature     DynamicActorIsolation:migrate         \
 // RUN:   -disable-experimental-feature DynamicActorIsolation:invalid4         \
-// RUN:   -disable-experimental-feature DynamicActorIsolation:adoption         \
+// RUN:   -disable-experimental-feature DynamicActorIsolation:migrate         \
 // RUN:   %s 2>&1 | %FileCheck %s --check-prefix=CHECK-SWIFT-6
 
 // REQUIRES: swift_feature_DynamicActorIsolation
@@ -34,18 +34,18 @@
 // CHECK-NOT: error:
 
 // CHECK-SWIFT-5-NOT: warning:
-// CHECK-SWIFT-5: warning: '-disable-experimental-feature' argument 'DynamicActorIsolation:adoption' cannot specify a mode [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5: warning: '-disable-experimental-feature' argument 'DynamicActorIsolation:migrate' cannot specify a mode [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NEXT: warning: '-disable-experimental-feature' argument 'DynamicActorIsolation:invalid8' cannot specify a mode [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NEXT: warning: '-disable-experimental-feature' argument 'DynamicActorIsolation:invalid7' cannot specify a mode [#StrictLanguageFeatures]{{$}}
-// CHECK-SWIFT-5-NEXT: warning: '-disable-upcoming-feature' argument 'DynamicActorIsolation:adoption' cannot specify a mode [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5-NEXT: warning: '-disable-upcoming-feature' argument 'DynamicActorIsolation:migrate' cannot specify a mode [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NEXT: warning: '-disable-upcoming-feature' argument 'DynamicActorIsolation:invalid6' cannot specify a mode [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NEXT: warning: '-disable-upcoming-feature' argument 'DynamicActorIsolation:invalid5' cannot specify a mode [#StrictLanguageFeatures]{{$}}
-// CHECK-SWIFT-5-NEXT: warning: feature 'DynamicActorIsolation' does not support adoption mode [#StrictLanguageFeatures]{{$}}
-// CHECK-SWIFT-5-NEXT: warning: feature 'DynamicActorIsolation' does not support adoption mode [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5-NEXT: warning: feature 'DynamicActorIsolation' does not support migration mode [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5-NEXT: warning: feature 'DynamicActorIsolation' does not support migration mode [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NEXT: warning: 'invalid4' is not a recognized mode for feature 'DynamicActorIsolation' [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NEXT: warning: 'invalid3' is not a recognized mode for feature 'DynamicActorIsolation' [#StrictLanguageFeatures]{{$}}
-// CHECK-SWIFT-5-NEXT: warning: feature 'DynamicActorIsolation' does not support adoption mode [#StrictLanguageFeatures]{{$}}
-// CHECK-SWIFT-5-NEXT: warning: feature 'DynamicActorIsolation' does not support adoption mode [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5-NEXT: warning: feature 'DynamicActorIsolation' does not support migration mode [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5-NEXT: warning: feature 'DynamicActorIsolation' does not support migration mode [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NEXT: warning: 'invalid2' is not a recognized mode for feature 'DynamicActorIsolation' [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NEXT: warning: 'invalid1' is not a recognized mode for feature 'DynamicActorIsolation' [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NOT: warning:
diff --git a/test/Frontend/features/adoption_mode_adoptable_feature.swift b/test/Frontend/features/adoption_mode_adoptable_feature.swift
index 213cf84df940e..635713b8099f4 100644
--- a/test/Frontend/features/adoption_mode_adoptable_feature.swift
+++ b/test/Frontend/features/adoption_mode_adoptable_feature.swift
@@ -3,20 +3,20 @@
 
 // RUN: %target-swift-frontend -parse -swift-version 6                         \
 // RUN:   -enable-upcoming-feature      ExistentialAny:invalid1                \
-// RUN:   -enable-upcoming-feature      ExistentialAny:adoption                \
+// RUN:   -enable-upcoming-feature      ExistentialAny:migrate                \
 // RUN:   -enable-experimental-feature  ExistentialAny:invalid2                \
-// RUN:   -enable-experimental-feature  ExistentialAny:adoption                \
-// RUN:   -disable-upcoming-feature     ExistentialAny:adoption                \
-// RUN:   -disable-experimental-feature ExistentialAny:adoption                \
+// RUN:   -enable-experimental-feature  ExistentialAny:migrate                \
+// RUN:   -disable-upcoming-feature     ExistentialAny:migrate                \
+// RUN:   -disable-experimental-feature ExistentialAny:migrate                \
 // RUN:   %s 2>&1 | %FileCheck %s --check-prefix=CHECK-SWIFT-5
 
 // RUN: %target-swift-frontend -parse -swift-version 7                         \
 // RUN:   -enable-upcoming-feature      ExistentialAny:invalid1                \
-// RUN:   -enable-upcoming-feature      ExistentialAny:adoption                \
+// RUN:   -enable-upcoming-feature      ExistentialAny:migrate                \
 // RUN:   -enable-experimental-feature  ExistentialAny:invalid2                \
-// RUN:   -enable-experimental-feature  ExistentialAny:adoption                \
-// RUN:   -disable-upcoming-feature     ExistentialAny:adoption                \
-// RUN:   -disable-experimental-feature ExistentialAny:adoption                \
+// RUN:   -enable-experimental-feature  ExistentialAny:migrate                \
+// RUN:   -disable-upcoming-feature     ExistentialAny:migrate                \
+// RUN:   -disable-experimental-feature ExistentialAny:migrate                \
 // RUN:   %s 2>&1 | %FileCheck %s --check-prefix=CHECK-SWIFT-7
 
 // REQUIRES: swift_feature_ExistentialAny
@@ -25,10 +25,10 @@
 // CHECK-NOT: error:
 
 // CHECK-SWIFT-5-NOT: warning:
-// CHECK-SWIFT-5: warning: '-disable-experimental-feature' argument 'ExistentialAny:adoption' cannot specify a mode [#StrictLanguageFeatures]{{$}}
-// CHECK-SWIFT-5-NEXT: warning: '-disable-upcoming-feature' argument 'ExistentialAny:adoption' cannot specify a mode [#StrictLanguageFeatures]{{$}}
-// CHECK-SWIFT-5-NEXT: warning: 'invalid2' is not a recognized mode for feature 'ExistentialAny'; did you mean 'adoption'? [#StrictLanguageFeatures]{{$}}
-// CHECK-SWIFT-5-NEXT: warning: 'invalid1' is not a recognized mode for feature 'ExistentialAny'; did you mean 'adoption'? [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5: warning: '-disable-experimental-feature' argument 'ExistentialAny:migrate' cannot specify a mode [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5-NEXT: warning: '-disable-upcoming-feature' argument 'ExistentialAny:migrate' cannot specify a mode [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5-NEXT: warning: 'invalid2' is not a recognized mode for feature 'ExistentialAny'; did you mean 'migrate'? [#StrictLanguageFeatures]{{$}}
+// CHECK-SWIFT-5-NEXT: warning: 'invalid1' is not a recognized mode for feature 'ExistentialAny'; did you mean 'migrate'? [#StrictLanguageFeatures]{{$}}
 // CHECK-SWIFT-5-NOT: warning:
 
 // CHECK-SWIFT-7-NOT: warning:
diff --git a/test/Frontend/features/upcoming_feature.swift b/test/Frontend/features/upcoming_feature.swift
index 58f10f47c4235..5883d20dc0f3b 100644
--- a/test/Frontend/features/upcoming_feature.swift
+++ b/test/Frontend/features/upcoming_feature.swift
@@ -1,34 +1,34 @@
 // Make sure that hasFeature(ConciseMagicFile) evaluates true when provided
 // explicitly.
-// RUN: %target-typecheck-verify-swift -enable-upcoming-feature ConciseMagicFile
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-upcoming-feature ConciseMagicFile
 
 // Make sure that hasFeature(ConciseMagicFile) evaluates true in Swift 6.
-// RUN: %target-typecheck-verify-swift -swift-version 6
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 6
 
 // Make sure that hasFeature(ConciseMagicFile) is off prior to Swift 6.
-// RUN: %target-typecheck-verify-swift -verify-additional-prefix swift5-
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-additional-prefix swift5-
 
 // It's fine to provide a feature that we don't know about.
-// RUN: %target-typecheck-verify-swift -enable-upcoming-feature ConciseMagicFile -enable-upcoming-feature UnknownFeature
-// RUN: %target-typecheck-verify-swift -enable-upcoming-feature UnknownFeature -enable-upcoming-feature ConciseMagicFile
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-upcoming-feature ConciseMagicFile -enable-upcoming-feature UnknownFeature
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-upcoming-feature UnknownFeature -enable-upcoming-feature ConciseMagicFile
 
 // When -disable-upcoming-feature is specified, leave the feature disabled.
-// RUN: %target-typecheck-verify-swift -disable-upcoming-feature ConciseMagicFile -verify-additional-prefix swift5-
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-upcoming-feature ConciseMagicFile -verify-additional-prefix swift5-
 
 // When both -enable-upcoming-feature and -disable-upcoming-feature are
 // specified, the result depends on the order.
-// RUN: %target-typecheck-verify-swift -enable-upcoming-feature ConciseMagicFile -disable-upcoming-feature ConciseMagicFile -verify-additional-prefix swift5-
-// RUN: %target-typecheck-verify-swift -disable-upcoming-feature ConciseMagicFile -enable-upcoming-feature ConciseMagicFile
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-upcoming-feature ConciseMagicFile -disable-upcoming-feature ConciseMagicFile -verify-additional-prefix swift5-
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-upcoming-feature ConciseMagicFile -enable-upcoming-feature ConciseMagicFile
 
 // For compatibility when a feature graduates, it's fine to refer to an
 // upcoming feature as an experimental feature.
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature ConciseMagicFile
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-experimental-feature ConciseMagicFile
 
 // A feature that has graduated can also be disabled as an experimental feature.
-// RUN: %target-typecheck-verify-swift -disable-experimental-feature ConciseMagicFile -verify-additional-prefix swift5-
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature ConciseMagicFile -disable-experimental-feature ConciseMagicFile -verify-additional-prefix swift5-
-// RUN: %target-typecheck-verify-swift -disable-experimental-feature ConciseMagicFile -enable-experimental-feature ConciseMagicFile
-// RUN: %target-typecheck-verify-swift -enable-upcoming-feature ConciseMagicFile -disable-experimental-feature ConciseMagicFile -verify-additional-prefix swift5-
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-experimental-feature ConciseMagicFile -verify-additional-prefix swift5-
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-experimental-feature ConciseMagicFile -disable-experimental-feature ConciseMagicFile -verify-additional-prefix swift5-
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-experimental-feature ConciseMagicFile -enable-experimental-feature ConciseMagicFile
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-upcoming-feature ConciseMagicFile -disable-experimental-feature ConciseMagicFile -verify-additional-prefix swift5-
 
 // Warn about enabled features that are implied by the specified language version.
 // RUN: %target-swift-frontend -typecheck -enable-upcoming-feature ConciseMagicFile -swift-version 6 %s 2>&1 | %FileCheck %s
diff --git a/test/Frontend/opt-record-supplemental.swift b/test/Frontend/opt-record-supplemental.swift
index b1f64d22e9513..e0fb11ffb4ff3 100644
--- a/test/Frontend/opt-record-supplemental.swift
+++ b/test/Frontend/opt-record-supplemental.swift
@@ -2,11 +2,17 @@
 // RUN: echo '"%s": { yaml-opt-record: "%t/foo.opt.yaml" }' > %t/filemap.yaml.yaml
 // RUN: echo '"%s": { bitstream-opt-record: "%t/foo.opt.bitstream" }' > %t/filemap.bitstream.yaml
 
-// RUN: %target-swift-frontend -c -O -wmo -save-optimization-record=bitstream %s -module-name foo -o %t/foo.o -supplementary-output-file-map %t/filemap.bitstream.yaml
+// RUN: %target-swift-frontend -c -O -num-threads 2 -save-optimization-record=bitstream %s %S/Inputs/opt-record-2.swift -module-name foo -o %t/foo.o  -o %t/opt-record-2.o -supplementary-output-file-map %t/filemap.bitstream.yaml
 // RUN: llvm-bcanalyzer -dump "%t/foo.opt.bitstream" | %FileCheck -check-prefix=BITSTREAM %s
+// RUN: llvm-bcanalyzer -dump "%t/opt-record-2.opt.bitstream" | %FileCheck -check-prefix=BITSTREAM2 %s
 
-// RUN: %target-swift-frontend -c -O -wmo -save-optimization-record=yaml %s -module-name foo -o %t/foo.o -supplementary-output-file-map %t/filemap.yaml.yaml
+// RUN: %empty-directory(%t)
+// RUN: echo '"%s": { yaml-opt-record: "%t/foo.opt.yaml" }' > %t/filemap.yaml.yaml
+// RUN: echo '"%s": { bitstream-opt-record: "%t/foo.opt.bitstream" }' > %t/filemap.bitstream.yaml
+
+// RUN: %target-swift-frontend -c -O -num-threads 2 -save-optimization-record=yaml %s %S/Inputs/opt-record-2.swift -module-name foo -o %t/foo.o -o %t/opt-record-2.o -supplementary-output-file-map %t/filemap.yaml.yaml
 // RUN: %FileCheck %s -check-prefix=YAML --input-file=%t/foo.opt.yaml
+// RUN: %FileCheck %s -check-prefix=YAML2 --input-file=%t/opt-record-2.opt.yaml
 
 // REQUIRES: VENDOR=apple
 
@@ -18,10 +24,19 @@ func foo() {
 }
 #sourceLocation() // reset
 
+@_assemblyVision
 public func bar() {
   foo()
+
+  runSomeTest(C())
   // BITSTREAM: <Remark NumWords=13 BlockCodeSize=4>
   // BITSTREAM: </Remark>
 
+  // BITSTREAM2: <Remark NumWords={{[0-9]+}} BlockCodeSize={{[0-9]*}}>
+  // BITSTREAM2: </Remark>
+
   // YAML: sil-assembly-vision-remark-gen
+
+  // YAML2: Pass: asm-printer
+  // YAML2: Name: InstructionCount
 }
diff --git a/test/Frontend/output_determinism_check.swift b/test/Frontend/output_determinism_check.swift
index b5320e7a178de..1502fb264376f 100644
--- a/test/Frontend/output_determinism_check.swift
+++ b/test/Frontend/output_determinism_check.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: echo '[]' > %t/protocol.json
-// RUN: %target-swift-frontend -module-name test -emit-module -o %t/test.swiftmodule %s -emit-module-doc-path %t/test.docc -const-gather-protocols-file %t/protocol.json -emit-const-values-path %t/test.swiftconstvalues -emit-tbd-path %t/test.tbd -tbd-current-version 1 -tbd-compatibility-version 1 -tbd-install_name @rpath/test.dylib -emit-loaded-module-trace -emit-loaded-module-trace-path %t/test.trace.json -enable-deterministic-check 2>&1 | %FileCheck %s --check-prefix=MODULE_OUTPUT --check-prefix=DOCC_OUTPUT --check-prefix=CONSTVALUE_OUTPUT --check-prefix=TBD_OUTPUT --check-prefix=TRACE_OUTPUT
+// RUN: %target-swift-frontend -module-name test -emit-module -o %t/test.swiftmodule %s -emit-module-doc-path %t/test.docc -const-gather-protocols-file %t/protocol.json -emit-const-values-path %t/test.swiftconstvalues -emit-symbol-graph -emit-symbol-graph-dir %t/symbols -emit-tbd-path %t/test.tbd -tbd-current-version 1 -tbd-compatibility-version 1 -tbd-install_name @rpath/test.dylib -emit-loaded-module-trace -emit-loaded-module-trace-path %t/test.trace.json -enable-deterministic-check 2>&1 | %FileCheck %s --check-prefix=MODULE_OUTPUT --check-prefix=DOCC_OUTPUT --check-prefix=CONSTVALUE_OUTPUT --check-prefix=TBD_OUTPUT --check-prefix=TRACE_OUTPUT --check-prefix=SYMBOLGRAPH_OUTPUT
 // RUN: %target-swift-frontend -module-name test -emit-sib -o %t/test.sib -primary-file %s -enable-deterministic-check 2>&1 | %FileCheck %s --check-prefix=SIB_OUTPUT
 
 /// object files are "not" deterministic because the second run going to match the mod hash and skip code generation.
@@ -22,6 +22,7 @@
 
 // RUN: %target-swift-frontend -emit-pcm -module-name UserClangModule -o %t/test.pcm %S/Inputs/dependencies/module.modulemap -enable-deterministic-check 2>&1 | %FileCheck %s --check-prefix=PCM_OUTPUT
 
+// SYMBOLGRAPH_OUTPUT: remark: produced matching output file '{{.*}}{{/|\\}}test.symbols.json'
 // DOCC_OUTPUT: remark: produced matching output file '{{.*}}{{/|\\}}test.docc'
 // CONSTVALUE_OUTPUT: remark: produced matching output file '{{.*}}{{/|\\}}test.swiftconstvalues'
 // MODULE_OUTPUT: remark: produced matching output file '{{.*}}{{/|\\}}test.swiftmodule'
diff --git a/test/Frontend/print-static-build-config.swift b/test/Frontend/print-static-build-config.swift
new file mode 100644
index 0000000000000..07ad1f9c72fea
--- /dev/null
+++ b/test/Frontend/print-static-build-config.swift
@@ -0,0 +1,10 @@
+// RUN: %target-swift-frontend -print-static-build-config -DSOMETHING | %FileCheck %s
+// REQUIRES: swift_swift_parser
+
+// CHECK: "attributes":
+// CHECK-SAME: "escaping"
+
+// CHECK-SAME: "customConditions":[{{.*"SOMETHING"[^]]*\]}}
+
+// CHECK-SAME: "features":
+// CHECK-SAME: "AttachedMacros"
diff --git a/test/Frontend/print-supported-features.swift b/test/Frontend/print-supported-features.swift
new file mode 100644
index 0000000000000..823df06357d57
--- /dev/null
+++ b/test/Frontend/print-supported-features.swift
@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend -print-supported-features | %FileCheck %s
+
+// CHECK: "features": {
+// CHECK-NEXT:   "optional": [
+// CHECK: { "name": "StrictMemorySafety", "migratable": true, "categories": ["StrictMemorySafety"], "flag_name": "-strict-memory-safety" },
+// CHECK: { "name": "LibraryEvolution", "flag_name": "-enable-library-evolution" }
+// CHECK-NEXT: ],
+// CHECK-NEXT:   "upcoming": [
+// CHECK:     { "name": "InferIsolatedConformances", "migratable": true, "categories": ["IsolatedConformances"], "enabled_in": "7" },
+// CHECK:   ],
+// CHECK:   "experimental": [
+// CHECK:     { "name": "BuiltinModule" }
+// CHECK:   ]
+// CHECK: }
diff --git a/test/Frontend/verify-broken-c-module.swift b/test/Frontend/verify-broken-c-module.swift
deleted file mode 100644
index 8fde2e5b9d672..0000000000000
--- a/test/Frontend/verify-broken-c-module.swift
+++ /dev/null
@@ -1,11 +0,0 @@
-// Tests that `-verify` mode outputs diagnostics from a failing C module
-// compilation.
-// This needs to be a separate test from verify.swift because compilation will
-// terminate after the failing import statement.
-
-// RUN: not %target-typecheck-verify-swift -I %S/Inputs/broken-c-module 2>&1 | %FileCheck %s
-
-// CHECK: [[@LINE+3]]:8: error: unexpected error produced: could not build
-// CHECK: note: diagnostic produced elsewhere: in file included from <module-includes>
-// CHECK: broken_c.h:2:11: error: diagnostic produced elsewhere: expected function body after function declarator
-import BrokenCModule
diff --git a/test/Frontend/verify-fixits.swift b/test/Frontend/verify-fixits.swift
deleted file mode 100644
index bd4399f82d5e3..0000000000000
--- a/test/Frontend/verify-fixits.swift
+++ /dev/null
@@ -1,271 +0,0 @@
-// Tests for fix-its on `-verify` mode.
-
-// RUN: not %target-typecheck-verify-swift 2>&1 | %FileCheck %s
-
-func labeledFunc(aa: Int, bb: Int) {}
-
-func testNoneMarkerCheck() {
-  // CHECK: [[@LINE+1]]:87: error: A second {{\{\{}}none}} was found. It may only appear once in an expectation.
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{none}} {{none}}
-
-  // CHECK: [[@LINE+1]]:134: error: {{\{\{}}none}} must be at the end.
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{none}} {{23-26=bb}}
-}
-
-func test0Fixits() {
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}}
-
-  // CHECK: [[@LINE+1]]:80: error: expected fix-it verification within braces; example: '1-2=text' or 'none'
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{}}
-
-  // CHECK: [[@LINE+1]]:81: error: expected line offset after leading '+' or '-' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+}}
-
-  // CHECK: [[@LINE+1]]:81: error: expected line offset after leading '+' or '-' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-}}
-
-  // CHECK: [[@LINE+1]]:81: error: expected '-' range separator in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected colon-separated column number after line offset in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-1}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected colon-separated column number after line offset in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:}}
-
-  // CHECK: [[@LINE+1]]:83: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:}}
-
-  // CHECK: [[@LINE+1]]:83: error: expected '-' range separator in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1}}
-
-  // CHECK: [[@LINE+1]]:84: error: expected '-' range separator in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-1:1}}
-
-  // CHECK: [[@LINE+1]]:83: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:-1}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected line or column number in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-}}
-
-  // CHECK: [[@LINE+1]]:84: error: expected line or column number in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-}}
-
-  // CHECK: [[@LINE+1]]:85: error: expected line or column number in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-1:1-}}
-
-  // CHECK: [[@LINE+1]]:83: error: expected line offset after leading '+' or '-' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1--}}
-
-  // CHECK: [[@LINE+1]]:83: error: expected '=' after range in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1}}
-
-  // CHECK: [[@LINE+1]]:85: error: expected '=' after range in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1}}
-
-  // CHECK: [[@LINE+1]]:86: error: expected '=' after range in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:1-1}}
-
-  // CHECK: [[@LINE+1]]:83: error: expected line offset after leading '+' or '-' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1--:}}
-
-  // CHECK: [[@LINE+1]]:84: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1:}}
-
-  // CHECK: [[@LINE+1]]:86: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1:}}
-
-  // CHECK: [[@LINE+1]]:87: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:1-1:}}
-
-  // CHECK: [[@LINE+1]]:85: error: expected '=' after range in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1:1}}
-
-  // CHECK: [[@LINE+1]]:86: error: expected '=' after range in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-+1:1}}
-
-  // CHECK: [[@LINE+1]]:87: error: expected '=' after range in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1:1}}
-
-  // CHECK: [[@LINE+1]]:89: error: expected '=' after range in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:1--1:1}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=a}}
-
-  // CHECK: [[@LINE+1]]:80: error: expected line or column number in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{x-1=a}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected line or column number in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-x=a}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:x-1=a}}
-
-  // CHECK: [[@LINE+1]]:80: error: expected line or column number in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{x:1-1=a}}
-
-  // CHECK: [[@LINE+1]]:81: error: expected line offset after leading '+' or '-' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+x:1-1=a}}
-
-  // CHECK: [[@LINE+1]]:84: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1:x=a}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected line or column number in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-x:1=a}}
-
-  // CHECK: [[@LINE+1]]:83: error: expected line offset after leading '+' or '-' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-+x:1=a}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:x-1:x=a}}
-
-  // CHECK: [[@LINE+1]]:80: error: expected line or column number in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{x:1-1:x=a}}
-
-  // CHECK: [[@LINE+1]]:81: error: expected line offset after leading '+' or '-' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+x:1-1:x=a}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:x-x:1=a}}
-
-  // CHECK: [[@LINE+1]]:82: error: expected column number after ':' in fix-it verification
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:x--x:1=a}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1:1=a}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1:1=a}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1:1-1=a}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{-1:1-1=a}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-+1:1=a}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{+1:1-+1:1=a}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=a}} {{2-2=b}}
-
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{none}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=a}} {{none}}
-
-  // CHECK: [[@LINE+1]]:78: error: expected fix-it not seen
-  undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{1-1=a}} {{2-2=b}} {{none}}
-}
-
-func test1Fixits() {
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}}
-
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}}
-
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}}
-
-  // CHECK: [[@LINE+1]]:134: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{15-18=xx}}
-
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}} {{15-18=aa}}
-
-  // CHECK: [[@LINE+1]]:121: error: expected no fix-its; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{none}}
-
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{none}}
-
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}} {{none}}
-
-  // CHECK: [[@LINE+1]]:134: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{15-18=xx}} {{none}}
-
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}} {{15-18=aa}} {{none}}
-
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{200:15-200:18=aa}}
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{202:15-18=aa}}
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-204:18=aa}}
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{-0:15-+0:18=aa}}
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15--0:18=aa}}
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {+0:15-210:18=aa}}
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{+1:15-+1:18=bb}}
-              bbx: 1)
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{216:15-+1:18=bb}}
-              bbx: 1)
-
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{61:15-18=aa}}
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{-1:15-18=aa}}
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{+0:15--1:18=aa}}
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
-  labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{61:15-+1:18=aa}}
-}
-
-func unlabeledFunc(_ aa: Int) {}
-
-func testDefaultedLineNumbers() {
-  // Fix-it end line defaults to first line.
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  unlabeledFunc(aa: // expected-error {{extraneous argument label 'aa:' in call}} {{+0:17-+1:5=}}
-    1)
-  // CHECK: [[@LINE+1]]:83: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}17-[[@LINE+2]]:5=}}
-  unlabeledFunc(aa: // expected-error {{extraneous argument label 'aa:' in call}} {{+0:17-5=}}
-    1)
-
-  // Fix-it start line defaults to diagnostic line.
-  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
-  labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{+1:15-+1:18=bb}}
-              bbx: 1)
-  // CHECK: [[@LINE+1]]:113: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}[[@LINE+2]]:15-18=bb}}
-  labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{15-+1:18=bb}}
-              bbx: 1)
-}
-
-func test2Fixits() {
-  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}}
-
-  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}}
-
-  // CHECK: [[@LINE+1]]:124: error: expected fix-it not seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
-  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=xx}}
-
-  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=bb}}
-
-  // CHECK: [[@LINE+1]]:137: error: expected fix-it not seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
-  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=xx}}
-
-  // CHECK: [[@LINE+1]]:124: error: expected no fix-its; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
-  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{none}}
-
-  // CHECK: [[@LINE+1]]:137: error: unexpected fix-it seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
-  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{none}}
-
-  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=bb}} {{none}}
-
-  // CHECK: [[@LINE+1]]:137: error: expected fix-it not seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
-  labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=xx}} {{none}}
-}
diff --git a/test/Generics/concrete_contraction_existential.swift b/test/Generics/concrete_contraction_existential.swift
new file mode 100644
index 0000000000000..9485728615e0d
--- /dev/null
+++ b/test/Generics/concrete_contraction_existential.swift
@@ -0,0 +1,13 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol P1 {
+  associatedtype Value
+}
+
+protocol P2 {
+  typealias A = Int
+}
+
+struct G<T: P1> where T.Value == any Collection, T.Value.Element: P2 {}
+// expected-error@-1 {{cannot access associated type 'Element' from 'any Collection'; use a concrete type or generic parameter base instead}}
+
diff --git a/test/Generics/conditional_conformances.swift b/test/Generics/conditional_conformances.swift
index 251047720410d..d7145c166b8cc 100644
--- a/test/Generics/conditional_conformances.swift
+++ b/test/Generics/conditional_conformances.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -debug-generic-signatures > %t.dump 2>&1
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -debug-generic-signatures > %t.dump 2>&1
 // RUN: %FileCheck %s < %t.dump
 
 protocol P1 {}
@@ -20,9 +20,9 @@ struct Free<T> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=Free
 // CHECK-NEXT:  (normal_conformance type="Free<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="Free<T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="Free<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="Free<T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="Free<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" conforms_to "P1"))
 extension Free: P2 where T: P1 {} 
 // expected-note@-1 {{requirement from conditional conformance of 'Free<U>' to 'P2'}} 
@@ -39,9 +39,9 @@ struct Constrained<T: P1> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=Constrained
 // CHECK-NEXT:  (normal_conformance type="Constrained<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="Constrained<T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="Constrained<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="Constrained<T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="Constrained<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" conforms_to "P3"))
 extension Constrained: P2 where T: P3 {} // expected-note {{requirement from conditional conformance of 'Constrained<U>' to 'P2'}}
 func constrained_good<U: P1 & P3>(_: U) {
@@ -56,9 +56,9 @@ struct RedundantSame<T: P1> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=RedundantSame
 // CHECK-NEXT: (normal_conformance type="RedundantSame<T>" protocol="P2"
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:     (builtin_conformance type="RedundantSame<T>" protocol="Copyable"))
+// CHECK-NEXT:     (builtin_conformance type="RedundantSame<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:     (builtin_conformance type="RedundantSame<T>" protocol="Escapable")))
+// CHECK-NEXT:     (builtin_conformance type="RedundantSame<T>" protocol="Escapable"{{.*}})))
 extension RedundantSame: P2 where T: P1 {}
 
 struct RedundantSuper<T: P4> {}
@@ -66,9 +66,9 @@ struct RedundantSuper<T: P4> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=RedundantSuper
 // CHECK-NEXT:  (normal_conformance type="RedundantSuper<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="RedundantSuper<T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="RedundantSuper<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="RedundantSuper<T>" protocol="Escapable")))
+// CHECK-NEXT:      (builtin_conformance type="RedundantSuper<T>" protocol="Escapable"{{.*}})))
 extension RedundantSuper: P2 where T: P1 {}
 
 struct OverlappingSub<T: P1> {}
@@ -76,9 +76,9 @@ struct OverlappingSub<T: P1> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=OverlappingSub
 // CHECK-NEXT:  (normal_conformance type="OverlappingSub<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="OverlappingSub<T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="OverlappingSub<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="OverlappingSub<T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="OverlappingSub<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" conforms_to "P4"))
 extension OverlappingSub: P2 where T: P4 {} // expected-note {{requirement from conditional conformance of 'OverlappingSub<U>' to 'P2'}}
 func overlapping_sub_good<U: P4>(_: U) {
@@ -94,9 +94,9 @@ struct SameType<T> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=SameType
 // CHECK-NEXT:  (normal_conformance type="SameType<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="SameType<Int>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="SameType<Int>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="SameType<Int>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="SameType<Int>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" same_type "Int"))
 extension SameType: P2 where T == Int {}
 // expected-note@-1 {{requirement from conditional conformance of 'SameType<U>' to 'P2'}}
@@ -115,9 +115,9 @@ struct SameTypeGeneric<T, U> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=SameTypeGeneric
 // CHECK-NEXT:  (normal_conformance type="SameTypeGeneric<T, U>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="SameTypeGeneric<T, T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="SameTypeGeneric<T, T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="SameTypeGeneric<T, T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="SameTypeGeneric<T, T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" same_type "U"))
 extension SameTypeGeneric: P2 where T == U {}
 // expected-note@-1 {{requirement from conditional conformance of 'SameTypeGeneric<U, Int>' to 'P2'}}
@@ -145,9 +145,9 @@ struct Infer<T, U> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=Infer
 // CHECK-NEXT:  (normal_conformance type="Infer<T, U>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="Infer<Constrained<U>, U>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="Infer<Constrained<U>, U>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="Infer<Constrained<U>, U>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="Infer<Constrained<U>, U>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" same_type "Constrained<U>")
 // CHECK-NEXT:    (requirement "U" conforms_to "P1"))
 extension Infer: P2 where T == Constrained<U> {}
@@ -168,9 +168,9 @@ struct InferRedundant<T, U: P1> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=InferRedundant
 // CHECK-NEXT:  (normal_conformance type="InferRedundant<T, U>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="InferRedundant<Constrained<U>, U>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="InferRedundant<Constrained<U>, U>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="InferRedundant<Constrained<U>, U>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="InferRedundant<Constrained<U>, U>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" same_type "Constrained<U>"))
 extension InferRedundant: P2 where T == Constrained<U> {}
 func infer_redundant_good<U: P1>(_: U) {
@@ -193,9 +193,9 @@ struct ClassFree<T> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=ClassFree
 // CHECK-NEXT:  (normal_conformance type="ClassFree<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="ClassFree<T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="ClassFree<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="ClassFree<T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="ClassFree<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" subclass_of "C1"))
 extension ClassFree: P2 where T: C1 {} // expected-note {{requirement from conditional conformance of 'ClassFree<U>' to 'P2'}}
 func class_free_good<U: C1>(_: U) {
@@ -211,9 +211,9 @@ struct ClassMoreSpecific<T: C1> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=ClassMoreSpecific
 // CHECK-NEXT:  (normal_conformance type="ClassMoreSpecific<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="ClassMoreSpecific<T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="ClassMoreSpecific<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="ClassMoreSpecific<T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="ClassMoreSpecific<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" subclass_of "C3"))
 extension ClassMoreSpecific: P2 where T: C3 {} // expected-note {{requirement from conditional conformance of 'ClassMoreSpecific<U>' to 'P2'}}
 func class_more_specific_good<U: C3>(_: U) {
@@ -230,9 +230,9 @@ struct ClassLessSpecific<T: C3> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=ClassLessSpecific
 // CHECK-NEXT:  (normal_conformance type="ClassLessSpecific<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="ClassLessSpecific<T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="ClassLessSpecific<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="ClassLessSpecific<T>" protocol="Escapable")))
+// CHECK-NEXT:      (builtin_conformance type="ClassLessSpecific<T>" protocol="Escapable"{{.*}})))
 extension ClassLessSpecific: P2 where T: C1 {}
 
 
@@ -257,9 +257,9 @@ struct InheritEqual<T> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=InheritEqual
 // CHECK-NEXT:  (normal_conformance type="InheritEqual<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="InheritEqual<T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="InheritEqual<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="InheritEqual<T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="InheritEqual<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" conforms_to "P1"))
 extension InheritEqual: P2 where T: P1 {} // expected-note {{requirement from conditional conformance of 'InheritEqual<U>' to 'P2'}}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=InheritEqual
@@ -268,9 +268,9 @@ extension InheritEqual: P2 where T: P1 {} // expected-note {{requirement from co
 // CHECK-LABEL:   (assoc_conformance type="Self" proto="P2"
 // CHECK-LABEL:     (normal_conformance type="InheritEqual<T>" protocol="P2"
 // CHECK-LABEL:       (assoc_conformance type="Self" proto="Copyable"
-// CHECK-LABEL:         (builtin_conformance type="InheritEqual<T>" protocol="Copyable"))
+// CHECK-LABEL:         (builtin_conformance type="InheritEqual<T>" protocol="Copyable"{{.*}}))
 // CHECK-LABEL:       (assoc_conformance type="Self" proto="Escapable"
-// CHECK-LABEL:         (builtin_conformance type="InheritEqual<T>" protocol="Escapable"))
+// CHECK-LABEL:         (builtin_conformance type="InheritEqual<T>" protocol="Escapable"{{.*}}))
 // CHECK-LABEL:       (requirement "T" conforms_to "P1")))
 // CHECK-LABEL:   (requirement "T" conforms_to "P1"))
 extension InheritEqual: P5 where T: P1 {} // expected-note {{requirement from conditional conformance of 'InheritEqual<U>' to 'P5'}}
@@ -298,9 +298,9 @@ struct InheritMore<T> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=InheritMore
 // CHECK-NEXT:  (normal_conformance type="InheritMore<T>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="InheritMore<T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="InheritMore<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="InheritMore<T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="InheritMore<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" conforms_to "P1"))
 extension InheritMore: P2 where T: P1 {} // expected-note {{requirement from conditional conformance of 'InheritMore<U>' to 'P2'}}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=InheritMore
@@ -309,9 +309,9 @@ extension InheritMore: P2 where T: P1 {} // expected-note {{requirement from con
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="P2"
 // CHECK-NEXT:      (normal_conformance type="InheritMore<T>" protocol="P2"
 // CHECK-NEXT:        (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:          (builtin_conformance type="InheritMore<T>" protocol="Copyable"))
+// CHECK-NEXT:          (builtin_conformance type="InheritMore<T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:        (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:          (builtin_conformance type="InheritMore<T>" protocol="Escapable"))
+// CHECK-NEXT:          (builtin_conformance type="InheritMore<T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:        (requirement "T" conforms_to "P1")))
 // CHECK-NEXT:    (requirement "T" conforms_to "P4"))
 extension InheritMore: P5 where T: P4 {} // expected-note 2 {{requirement from conditional conformance of 'InheritMore<U>' to 'P5'}}
@@ -398,9 +398,9 @@ struct RedundancyOrderDependenceGood<T: P1, U> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=RedundancyOrderDependenceGood
 // CHECK-NEXT:  (normal_conformance type="RedundancyOrderDependenceGood<T, U>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="RedundancyOrderDependenceGood<T, T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="RedundancyOrderDependenceGood<T, T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="RedundancyOrderDependenceGood<T, T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="RedundancyOrderDependenceGood<T, T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" same_type "U"))
 extension RedundancyOrderDependenceGood: P2 where U: P1, T == U {}
 
@@ -409,9 +409,9 @@ struct RedundancyOrderDependenceBad<T, U: P1> {}
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=RedundancyOrderDependenceBad
 // CHECK-NEXT:  (normal_conformance type="RedundancyOrderDependenceBad<T, U>" protocol="P2"
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Copyable"
-// CHECK-NEXT:      (builtin_conformance type="RedundancyOrderDependenceBad<T, T>" protocol="Copyable"))
+// CHECK-NEXT:      (builtin_conformance type="RedundancyOrderDependenceBad<T, T>" protocol="Copyable"{{.*}}))
 // CHECK-NEXT:    (assoc_conformance type="Self" proto="Escapable"
-// CHECK-NEXT:      (builtin_conformance type="RedundancyOrderDependenceBad<T, T>" protocol="Escapable"))
+// CHECK-NEXT:      (builtin_conformance type="RedundancyOrderDependenceBad<T, T>" protocol="Escapable"{{.*}}))
 // CHECK-NEXT:    (requirement "T" conforms_to "P1")
 // CHECK-NEXT:    (requirement "T" same_type "U"))
 extension RedundancyOrderDependenceBad: P2 where T: P1, T == U {}
diff --git a/test/Generics/conditional_conformances_objc.swift b/test/Generics/conditional_conformances_objc.swift
index c74915af8729c..ebd73aea22541 100644
--- a/test/Generics/conditional_conformances_objc.swift
+++ b/test/Generics/conditional_conformances_objc.swift
@@ -37,6 +37,6 @@ extension ObjC.Class: Bar where T: Bar {}
 class X<T> {}
 
 extension X: ObjCProtocol where T: Foo {}
-// expected-error@-1{{type 'X<T>' cannot conditionally conform to @objc protocol 'ObjCProtocol' because Objective-C does not support conditional conformances}}
+// expected-error@-1{{type 'X<T>' cannot conditionally conform to '@objc' protocol 'ObjCProtocol' because Objective-C does not support conditional conformances}}
 extension X: AtObjCProtocol where T: Foo {}
-// expected-error@-1{{type 'X<T>' cannot conditionally conform to @objc protocol 'AtObjCProtocol' because Objective-C does not support conditional conformances}}
+// expected-error@-1{{type 'X<T>' cannot conditionally conform to '@objc' protocol 'AtObjCProtocol' because Objective-C does not support conditional conformances}}
diff --git a/test/Generics/deduction.swift b/test/Generics/deduction.swift
index 1612d1ce6e139..7b35f6cbe3ab5 100644
--- a/test/Generics/deduction.swift
+++ b/test/Generics/deduction.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 //===----------------------------------------------------------------------===//
 // Deduction of generic arguments
diff --git a/test/Generics/function_decls.swift b/test/Generics/function_decls.swift
index a20d73389aff9..9b1da36e8144e 100644
--- a/test/Generics/function_decls.swift
+++ b/test/Generics/function_decls.swift
@@ -24,7 +24,7 @@ public class A<X> {
   public func f11<T, U>(x: X, y: T) {} //expected-error{{generic parameter 'U' is not used in function signature}}
 }
 
-struct G<T> {} // expected-note {{generic type 'G' declared here}}
+struct G<T> {} // expected-note {{generic struct 'G' declared here}}
 
 struct GG<T, U> {}
 
diff --git a/test/Generics/function_defs.swift b/test/Generics/function_defs.swift
index 8d73d94f126d3..c35df8e68a07e 100644
--- a/test/Generics/function_defs.swift
+++ b/test/Generics/function_defs.swift
@@ -289,7 +289,7 @@ func badTypeConformance3<T>(_: T) where (T) -> () : EqualComparable { }
 // expected-error@-1{{type '(T) -> ()' in conformance requirement does not refer to a generic parameter or associated type}}
 
 func badTypeConformance4<T>(_: T) where @escaping (inout T) throws -> () : EqualComparable { }
-// expected-error@-1 {{@escaping attribute may only be used in function parameter position}}
+// expected-error@-1 {{'@escaping' may only be used in function parameter position}}
 
 func badTypeConformance5<T>(_: T) where T & Sequence : EqualComparable { }
 // expected-error@-1 {{non-protocol, non-class type 'T' cannot be used within a protocol-constrained type}}
diff --git a/test/Generics/generic_types.swift b/test/Generics/generic_types.swift
index 998bc845dd5de..6103996ea3825 100644
--- a/test/Generics/generic_types.swift
+++ b/test/Generics/generic_types.swift
@@ -107,7 +107,7 @@ struct Dict<K, V> {
   subscript(key: K) -> V { get {} set {} }
 }
 
-class Dictionary<K, V> { // expected-note{{generic type 'Dictionary' declared here}}
+class Dictionary<K, V> { // expected-note{{generic class 'Dictionary' declared here}}
   subscript(key: K) -> V { get {} set {} }
 }
 
diff --git a/test/Generics/infinite_concrete_type.swift b/test/Generics/infinite_concrete_type.swift
index 399efefc91d42..02b271fb02ff1 100644
--- a/test/Generics/infinite_concrete_type.swift
+++ b/test/Generics/infinite_concrete_type.swift
@@ -2,8 +2,8 @@
 
 class G<T> {}
 
-protocol P1 { // expected-error {{cannot build rewrite system for protocol; concrete nesting limit exceeded}}
-// expected-note@-1 {{failed rewrite rule is [P1:A].[concrete: G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<[P1].A>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>] => [P1:A]}}
+protocol P1 { // expected-error {{cannot build rewrite system for protocol; concrete type difference limit exceeded}}
+// expected-note@-1 {{failed rewrite rule is [P1:B].[superclass: G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<[P1].B>>>>>>>>>>>>>>>>>>>>>>] => [P1:B]}}
   associatedtype A where A == G<B>
   associatedtype B where B == G<A>
 }
@@ -19,3 +19,40 @@ func useP2<T : P2>(_: T) {
   _ = T.A.self
   _ = T.B.self
 }
+
+protocol P3 {
+  associatedtype T : P3
+}
+
+struct S<U : P3> : P3 {
+  typealias T = S<S<U>>
+}
+
+protocol P4Base {
+  associatedtype T : P3
+  associatedtype U : P3
+}
+
+protocol P4 : P4Base where T == S<U> {
+// expected-error@-1 {{cannot build rewrite system for protocol; rule length limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is [P4:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[concrete: S<S<S<S<S<S<S<S<S<S<S<S<S<S<[P4:U]>>>>>>>>>>>>>>] => [P4:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T].[P3:T]}}
+}
+
+protocol Exponential {
+// expected-error@-1 {{cannot build rewrite system for protocol; concrete type size limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is }}
+  associatedtype A where A == (A, A)
+}
+
+class Base<T> {}
+
+class Derived<T, U> : Base<(T, U)> {}
+
+protocol TooManyDifferences {
+// expected-error@-1 {{cannot build rewrite system for protocol; concrete type difference limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is }}
+  associatedtype A1 where A1: Derived<B, C>, A2: Base<B>, A1 == A2
+  associatedtype A2
+  associatedtype B
+  associatedtype C
+}
\ No newline at end of file
diff --git a/test/Generics/infinite_opaque_result_type.swift b/test/Generics/infinite_opaque_result_type.swift
new file mode 100644
index 0000000000000..07ae7bf61cd5c
--- /dev/null
+++ b/test/Generics/infinite_opaque_result_type.swift
@@ -0,0 +1,73 @@
+// RUN: %target-typecheck-verify-swift
+
+func concrete1() -> some Any {
+// expected-error@-1 {{function declares an opaque return type, but has no return statements in its body from which to infer an underlying type}}
+  return concrete1()
+}
+
+func concrete2() -> some Any {  // expected-error {{function opaque return type was inferred as '[some Any]', which defines the opaque type in terms of itself}}
+  return [concrete2()]
+}
+
+
+func concrete1a() -> some Any {  // expected-error {{function opaque return type was inferred as 'some Any', which defines the opaque type in terms of itself}}
+  return concrete1b()
+}
+
+func concrete1b() -> some Any {  // expected-error {{function opaque return type was inferred as 'some Any', which defines the opaque type in terms of itself}}
+  return concrete1a()
+}
+
+
+func concrete2a() -> some Any {  // expected-error {{function opaque return type was inferred as '[some Any]', which defines the opaque type in terms of itself}}
+  return [concrete2b()]
+}
+
+func concrete2b() -> some Any {  // expected-error {{function opaque return type was inferred as '[some Any]', which defines the opaque type in terms of itself}}
+  return [concrete2a()]
+}
+
+
+func generic1<T>(_ t: T) -> some Any {
+// expected-error@-1 {{function declares an opaque return type, but has no return statements in its body from which to infer an underlying type}}
+  return generic1(t)
+}
+
+func generic2<T>(_ t: T) -> some Any {  // expected-error {{function opaque return type was inferred as '[some Any]', which defines the opaque type in terms of itself}}
+  return [generic2(t)]
+}
+
+
+func generic1a<T>(_ t: T) -> some Any {  // expected-error {{function opaque return type was inferred as 'some Any', which defines the opaque type in terms of itself}}
+  return generic1b(t)
+}
+
+func generic1b<T>(_ t: T) -> some Any {  // expected-error {{function opaque return type was inferred as 'some Any', which defines the opaque type in terms of itself}}
+  return generic1a(t)
+}
+
+
+func generic2a<T>(_ t: T) -> some Any {  // expected-error {{function opaque return type was inferred as '[some Any]', which defines the opaque type in terms of itself}}
+  return [generic2b(t)]
+}
+
+func generic2b<T>(_ t: T) -> some Any {  // expected-error {{function opaque return type was inferred as '[some Any]', which defines the opaque type in terms of itself}}
+  return [generic2a(t)]
+}
+
+
+func generic3a<T>(_ t: T) -> some Any {  // expected-error {{function opaque return type was inferred as '[some Any]', which defines the opaque type in terms of itself}}
+  return [generic3b(t)]
+}
+
+func generic3b<T>(_ t: T) -> some Any {  // expected-error {{function opaque return type was inferred as '[some Any]', which defines the opaque type in terms of itself}}
+  return [generic3a([t])]
+}
+
+func very_wide1() -> some Any {  // expected-error {{function opaque return type was inferred as '(some Any, some Any)', which defines the opaque type in terms of itself}}
+  return (very_wide2(), very_wide2())
+}
+
+func very_wide2() -> some Any {  // expected-error {{function opaque return type was inferred as '(some Any, some Any)', which defines the opaque type in terms of itself}}
+  return (very_wide1(), very_wide1())
+}
\ No newline at end of file
diff --git a/test/Generics/inheritance.swift b/test/Generics/inheritance.swift
index 40b6b76458885..039a91e63abd5 100644
--- a/test/Generics/inheritance.swift
+++ b/test/Generics/inheritance.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 class A {
   func foo() { }
diff --git a/test/Generics/invalid.swift b/test/Generics/invalid.swift
index 3bf1d0be1b44c..3736d569c0271 100644
--- a/test/Generics/invalid.swift
+++ b/test/Generics/invalid.swift
@@ -154,3 +154,13 @@ func errorMessageVariants(x: X<Int>, x2: X<Bool> = X<Int>()) -> X<Bool> {
   let _: X<Int>.Foo = X<Bool>.Foo() // expected-error {{cannot convert parent type 'X<Bool>' to expected type 'X<Int>'}}
   return x // expected-error {{cannot convert return expression of type 'X<Int>' to return type 'X<Bool>'}}
 }
+
+protocol P2 {
+  func foo()
+}
+
+// Make sure we don't diagnose the conformance failure or 'T.K'.
+struct HasInvalidSameType<T>: P2 where T == Undefined, T.K == Int {
+  // expected-error@-1 {{cannot find type 'Undefined' in scope}}
+  func foo() {}
+}
diff --git a/test/Generics/inverse_copyable_requirement.swift b/test/Generics/inverse_copyable_requirement.swift
index a4579f5181d4d..35806a7a60eec 100644
--- a/test/Generics/inverse_copyable_requirement.swift
+++ b/test/Generics/inverse_copyable_requirement.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // a concrete move-only type
 struct MO: ~Copyable {
diff --git a/test/Generics/inverse_extension_signatures.swift b/test/Generics/inverse_extension_signatures.swift
index 863626580c4c5..f3a304a24dbe9 100644
--- a/test/Generics/inverse_extension_signatures.swift
+++ b/test/Generics/inverse_extension_signatures.swift
@@ -20,7 +20,7 @@
 // CHECK-LABEL: .Outer.InnerStruct.init()@
 // CHECK: Generic signature: <A, C where A : Escapable, C : Escapable>
 
-// CHECK: (builtin_conformance type="Outer<A>.InnerStruct<C>" protocol="Escapable")
+// CHECK: (builtin_conformance type="Outer<A>.InnerStruct<C>" protocol="Escapable"{{.*}})
 
 // CHECK-LABEL: .Outer.InnerVariation1@
 // CHECK: Generic signature: <A, D where A : Escapable, D : Escapable>
diff --git a/test/Generics/inverse_generics.swift b/test/Generics/inverse_generics.swift
index 3930eda3a3c1e..fdf886c9065de 100644
--- a/test/Generics/inverse_generics.swift
+++ b/test/Generics/inverse_generics.swift
@@ -1,8 +1,8 @@
 // RUN: %target-typecheck-verify-swift \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: -enable-experimental-feature SuppressedAssociatedTypes
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_SuppressedAssociatedTypes
 
 // expected-note@+1 {{'T' has '~Copyable' constraint preventing implicit 'Copyable' conformance}}
@@ -249,7 +249,7 @@ struct BuggerView<T: ~Copyable>: ~Escapable, Copyable {}
 
 struct MutableBuggerView<T: ~Copyable>: ~Copyable, ~Escapable {}
 
-@lifetime(mutRef: copy mutRef)
+@_lifetime(mutRef: copy mutRef)
 func checkNominals(_ mutRef: inout MutableBuggerView<NC>,
                    _ ref: BuggerView<NC>,
                    _ intMutRef: borrowing MutableBuggerView<Int>,
@@ -365,9 +365,9 @@ func conflict13<T>(_ t: T)
         {}
 
 // expected-warning@+1 {{same-type requirement makes generic parameters 'U' and 'T' equivalent}}
-func conflict14<T, U>(_ t: T, _ u: U)
-  where T: ~Copyable, // expected-error {{'T' required to be 'Copyable' but is marked with '~Copyable'}}
-        U: ~Escapable, // expected-error {{'U' required to be 'Escapable' but is marked with '~Escapable'}}
+func conflict14<T, U>(_ t: borrowing T, _ u: borrowing U)
+  where T: ~Copyable,
+        U: ~Escapable,
         T == U {}
 
 protocol Conflict15 {
@@ -538,5 +538,5 @@ func testYap(_ y: Yapping<NC>) {
 protocol Veggie: ~Copyable {}
 func generalized(_ x: Any.Type) {}
 func testMetatypes(_ t: (any Veggie & ~Copyable).Type) {
-  generalized(t) // expected-error {{cannot convert value of type '(any Veggie & ~Copyable).Type' to expected argument type 'any Any.Type'}}
+  generalized(t) // expected-error {{argument type 'any Veggie & ~Copyable' does not conform to expected type 'Copyable'}}
 }
diff --git a/test/Generics/inverse_signatures.swift b/test/Generics/inverse_signatures.swift
index dab9aaf39b82d..21ba6df0b4bbe 100644
--- a/test/Generics/inverse_signatures.swift
+++ b/test/Generics/inverse_signatures.swift
@@ -197,13 +197,13 @@ extension Cond: Copyable where T: Copyable {}
 struct FullyGenericArg<T: ~Escapable & ~Copyable> {}
 
 // CHECK-LABEL: StructDecl name=FullyGenericArg
-// CHECK-NEXT:    (builtin_conformance type="FullyGenericArg<T>" protocol="Copyable")
-// CHECK-NEXT:    (builtin_conformance type="FullyGenericArg<T>" protocol="Escapable")
+// CHECK-NEXT:    (builtin_conformance type="FullyGenericArg<T>" protocol="Copyable"{{.*}})
+// CHECK-NEXT:    (builtin_conformance type="FullyGenericArg<T>" protocol="Escapable"{{.*}})
 
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=FullyGenericArg
 // CHECK: Generic signature: <T>
 // CHECK-NEXT: Canonical generic signature: <τ_0_0>
 
 // CHECK-LABEL: ExtensionDecl line={{.*}} base=FullyGenericArg
-// CHECK-NEXT: (normal_conformance type="FullyGenericArg<T>" protocol="Empty")
+// CHECK-NEXT: (normal_conformance type="FullyGenericArg<T>" protocol="Empty"{{.*}})
 extension FullyGenericArg: Empty where T: ~Copyable, T: ~Escapable {}
diff --git a/test/Generics/issue-55666.swift b/test/Generics/issue-55666.swift
index 812c22d6f7478..b6dcebcf67d1e 100644
--- a/test/Generics/issue-55666.swift
+++ b/test/Generics/issue-55666.swift
@@ -7,16 +7,16 @@ struct W<T> {}
 struct S<C1: Collection> {
   init(){}
   // expected-note@+2 {{where 'C1.Element' = 'W<C1>', 'main.W<C2.Element>' = 'main.W<C2.Element>'}}
-  // expected-note@+1 {{where 'C1.Element' = 'W<String>', 'W<C2.Element>' = 'W<Array<Int>.Element>'}}
+  // expected-note@+1 {{where 'C1.Element' = 'W<String>', 'W<C2.Element>' = 'W<Int>'}}
   init<C2>(_ c2: W<C2>) where C2: Collection, C1.Element == W<C2.Element> {}
-  // expected-note@+1 {{where 'C1.Element' = 'W<String>', 'W<C2.Element>' = 'W<Array<Int>.Element>'}}
+  // expected-note@+1 {{where 'C1.Element' = 'W<String>', 'W<C2.Element>' = 'W<Int>'}}
   static func f<C2>(_ c2: W<C2>) where C2: Collection, C1.Element == W<C2.Element> {}
-  // expected-note@+1 {{where 'C1.Element' = 'W<String>', 'W<C2.Element>' = 'W<Array<Int>.Element>'}}
+  // expected-note@+1 {{where 'C1.Element' = 'W<String>', 'W<C2.Element>' = 'W<Int>'}}
   func instancef<C2>(_ c2: W<C2>) where C2: Collection, C1.Element == W<C2.Element> {}
 }
-let _ = S<[W<String>]>(W<[Int]>()) // expected-error{{initializer 'init(_:)' requires the types 'W<String>' and 'W<Array<Int>.Element>' be equivalent}}
-let _ = S<[W<String>]>.f(W<[Int]>()) // expected-error{{static method 'f' requires the types 'W<String>' and 'W<Array<Int>.Element>' be equivalent}}
-let _ = S<[W<String>]>().instancef(W<[Int]>()) // expected-error{{instance method 'instancef' requires the types 'W<String>' and 'W<Array<Int>.Element>' be equivalent}}
+let _ = S<[W<String>]>(W<[Int]>()) // expected-error{{initializer 'init(_:)' requires the types 'W<String>' and 'W<Int>' be equivalent}}
+let _ = S<[W<String>]>.f(W<[Int]>()) // expected-error{{static method 'f' requires the types 'W<String>' and 'W<Int>' be equivalent}}
+let _ = S<[W<String>]>().instancef(W<[Int]>()) // expected-error{{instance method 'instancef' requires the types 'W<String>' and 'W<Int>' be equivalent}}
 
 // Archetypes requirement failure
 func genericFunc<C1: Collection, C2: Collection>(_ c2: W<C2>, c1: C1.Type) where C1.Element == W<C2.Element> {
diff --git a/test/Generics/issue-69318.swift b/test/Generics/issue-69318.swift
index a0eb7d58a04d2..c198509c5ef6f 100644
--- a/test/Generics/issue-69318.swift
+++ b/test/Generics/issue-69318.swift
@@ -15,6 +15,7 @@ public protocol ChildlessView: View where NodeChildren == EmptyViewGraphNodeChil
 // expected-error@-1 {{circular reference}}
 
 public struct EmptyViewGraphNodeChildren<ParentView: ChildlessView>: ViewGraphNodeChildren {}
-// expected-note@-1 3{{through reference here}}
-// expected-error@-2 {{type 'EmptyViewGraphNodeChildren<ParentView>' does not conform to protocol 'ViewGraphNodeChildren'}}
-// expected-note@-3 {{add stubs for conformance}}
+// expected-note@-1:15 {{through reference here}}
+// expected-note@-2:70 {{through reference here}}
+// expected-error@-3 {{type 'EmptyViewGraphNodeChildren<ParentView>' does not conform to protocol 'ViewGraphNodeChildren'}}
+// expected-note@-4 {{add stubs for conformance}}
diff --git a/test/Generics/issue-84419.swift b/test/Generics/issue-84419.swift
new file mode 100644
index 0000000000000..1c7421141052d
--- /dev/null
+++ b/test/Generics/issue-84419.swift
@@ -0,0 +1,7 @@
+// RUN: %target-typecheck-verify-swift -swift-version 6
+
+struct G<T: Sequence> where T == Int {
+// expected-error@-1 {{no type for 'T' can satisfy both 'T == Int' and 'T : Sequence'}}
+// expected-error@-2 {{same-type requirement makes generic parameter 'T' non-generic}}
+  let t: T
+}
diff --git a/test/Generics/non_confluent.swift b/test/Generics/non_confluent.swift
deleted file mode 100644
index d0f9fbcc664f9..0000000000000
--- a/test/Generics/non_confluent.swift
+++ /dev/null
@@ -1,54 +0,0 @@
-// RUN: %target-typecheck-verify-swift
-
-protocol ABA // expected-error {{cannot build rewrite system for protocol; rule length limit exceeded}}
-// expected-note@-1 {{failed rewrite rule is [ABA:A].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:A] => [ABA:A].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B]}}
-    where A.B == A.B.A { // expected-error *{{is not a member type}}
-  associatedtype A : ABA
-  associatedtype B : ABA
-}
-
-protocol Undecidable // expected-error {{cannot build rewrite system for protocol; rule length limit exceeded}}
-// expected-note@-1 {{failed rewrite rule is [Undecidable:A].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:D].[Undecidable:C].[Undecidable:E].[Undecidable:E].[Undecidable:B].[Undecidable:B].[Undecidable:A].[Undecidable:B].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:D].[Undecidable:D] => [Undecidable:A].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:D].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:D].[Undecidable:D].[Undecidable:E].[Undecidable:A].[Undecidable:B]}}
-    where A.C == C.A, // expected-error *{{is not a member type}}
-          A.D == D.A, // expected-error *{{is not a member type}}
-          B.C == C.B, // expected-error *{{is not a member type}}
-          B.D == D.B, // expected-error *{{is not a member type}}
-          C.E == E.C.A, // expected-error *{{is not a member type}}
-          D.E == E.D.B, // expected-error *{{is not a member type}}
-          C.C.A == C.C.A.E { // expected-error *{{is not a member type}}
-  associatedtype A : Undecidable
-  associatedtype B : Undecidable
-  associatedtype C : Undecidable
-  associatedtype D : Undecidable
-  associatedtype E : Undecidable
-}
-
-protocol P1 {
-  associatedtype T : P1
-}
-
-protocol P2 {
-  associatedtype T : P2
-}
-
-func foo<T : P1 & P2>(_: T) {}
-// expected-error@-1 {{cannot build rewrite system for generic signature; rule length limit exceeded}}
-// expected-note@-2 {{failed rewrite rule is τ_0_0.[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P2] => τ_0_0.[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T]}}
-
-extension P1 where Self : P2 {}
-// expected-error@-1 {{cannot build rewrite system for generic signature; rule length limit exceeded}}
-// expected-note@-2 {{failed rewrite rule is τ_0_0.[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P2] => τ_0_0.[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T]}}
-
-struct S<U : P1> : P1 {
-  typealias T = S<S<U>>
-}
-
-protocol P3Base {
-  associatedtype T : P1
-  associatedtype U : P1
-}
-
-protocol P3 : P3Base where T == S<U> {
-// expected-error@-1 {{cannot build rewrite system for protocol; rule length limit exceeded}}
-// expected-note@-2 {{failed rewrite rule is [P3:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[concrete: S<S<S<S<S<S<S<S<S<S<S<S<S<S<[P3:U]>>>>>>>>>>>>>>] => [P3:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T]}}
-}
diff --git a/test/Generics/non_fcrs.swift b/test/Generics/non_fcrs.swift
new file mode 100644
index 0000000000000..84966b4d8e21e
--- /dev/null
+++ b/test/Generics/non_fcrs.swift
@@ -0,0 +1,87 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol ABA // expected-error {{cannot build rewrite system for protocol; rule length limit exceeded}}
+// expected-note@-1 {{failed rewrite rule is [ABA:A].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:A] => [ABA:A].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B].[ABA:B]}}
+    where A.B == A.B.A { // expected-error *{{is not a member type}}
+  associatedtype A : ABA
+  associatedtype B : ABA
+}
+
+protocol Undecidable // expected-error {{cannot build rewrite system for protocol; rule length limit exceeded}}
+// expected-note@-1 {{failed rewrite rule is [Undecidable:A].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:D].[Undecidable:C].[Undecidable:E].[Undecidable:E].[Undecidable:B].[Undecidable:B].[Undecidable:A].[Undecidable:B].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:D].[Undecidable:D] => [Undecidable:A].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:D].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:C].[Undecidable:D].[Undecidable:D].[Undecidable:E].[Undecidable:A].[Undecidable:B]}}
+    where A.C == C.A, // expected-error *{{is not a member type}}
+          A.D == D.A, // expected-error *{{is not a member type}}
+          B.C == C.B, // expected-error *{{is not a member type}}
+          B.D == D.B, // expected-error *{{is not a member type}}
+          C.E == E.C.A, // expected-error *{{is not a member type}}
+          D.E == E.D.B, // expected-error *{{is not a member type}}
+          C.C.A == C.C.A.E { // expected-error *{{is not a member type}}
+  associatedtype A : Undecidable
+  associatedtype B : Undecidable
+  associatedtype C : Undecidable
+  associatedtype D : Undecidable
+  associatedtype E : Undecidable
+}
+
+protocol P1 {
+  associatedtype T : P1
+}
+
+protocol P2 {
+  associatedtype T : P2
+}
+
+protocol P12: P1, P2 {}
+// expected-error@-1 {{cannot build rewrite system for protocol; rule length limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is [P12:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P2] => [P12:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T]}}
+
+func foo<T : P1 & P2>(_: T) {}
+// expected-error@-1 {{cannot build rewrite system for generic signature; rule length limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is τ_0_0.[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P2] => τ_0_0.[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T]}}
+
+extension P1 where Self : P2 {}
+// expected-error@-1 {{cannot build rewrite system for generic signature; rule length limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is τ_0_0.[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P2] => τ_0_0.[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T].[P1:T]}}
+
+protocol M0 {
+// expected-error@-1 {{cannot build rewrite system for protocol; rule length limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is }}
+  associatedtype A: M0
+  associatedtype B: M0
+  associatedtype C: M0
+    where A.B == Self, C.A == B.C  // expected-error *{{is not a member type}}
+}
+
+protocol M1 {
+// expected-error@-1 {{cannot build rewrite system for protocol; rule length limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is }}
+  associatedtype A: M1
+  associatedtype B: M1
+  associatedtype C: M1
+    where C.A.C == A, A.B.A == A  // expected-error *{{is not a member type}}
+}
+
+protocol M2 {
+// expected-error@-1 {{cannot build rewrite system for protocol; rule length limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is }}
+  associatedtype A: M2
+  associatedtype B: M2
+  associatedtype C: M2
+    where B.A == A.B, C.A == A, A.C == A  // expected-error *{{is not a member type}}
+}
+
+protocol M3 {
+// expected-error@-1 {{cannot build rewrite system for protocol; rule length limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is }}
+  associatedtype A: M3
+  associatedtype B: M3
+    where A.A.A == A, A.B.B.A == B.B  // expected-error *{{is not a member type}}
+}
+
+protocol M4 {
+// expected-error@-1 {{cannot build rewrite system for protocol; rule length limit exceeded}}
+// expected-note@-2 {{failed rewrite rule is }}
+  associatedtype A: M4
+  associatedtype B: M4
+    where B.A.A == A.A.B, A.B.A == A.A  // expected-error *{{is not a member type}}
+}
diff --git a/test/Generics/pack_same_type_requirements.swift b/test/Generics/pack_same_type_requirements.swift
new file mode 100644
index 0000000000000..783a10ab4927b
--- /dev/null
+++ b/test/Generics/pack_same_type_requirements.swift
@@ -0,0 +1,25 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol PipelineItem {
+    associatedtype Input
+    associatedtype Output
+}
+
+// This example will never work; eventually, it will produce a more precise diagnostic.
+func bad<First : PipelineItem,
+         each T : PipelineItem,
+         Last : PipelineItem>(_ first: First, _ rest: repeat each T, last: Last)
+    where (First.Output, repeat (each T).Output) == (repeat (each T).Input, Last.Input) {}
+    // expected-error@-1 2{{same-type requirements between packs and concrete types are not yet supported}}
+
+// This is also invalid.
+func bad2<First : PipelineItem,
+          each T : PipelineItem>(_ first: First, _ rest: repeat each T)
+    where repeat (each T).Output == (First, repeat (each T).Input) {}
+    // expected-error@-1 {{same-type requirements between packs and concrete types are not yet supported}}
+
+// This could eventually be made to work.
+func good<First : PipelineItem,
+          each T : PipelineItem>(_ first: First, _ rest: repeat each T)
+    where (repeat (each T).Output) == (First, repeat (each T).Input) {}
+    // expected-error@-1 {{generic signature requires types '(repeat (each T).Output)' and '(First, repeat (each T).Input)' to be the same}}
diff --git a/test/Generics/parameter-pack-requirements.swift b/test/Generics/parameter-pack-requirements.swift
index 549ac64b50d64..fd4b67ed45d35 100644
--- a/test/Generics/parameter-pack-requirements.swift
+++ b/test/Generics/parameter-pack-requirements.swift
@@ -117,7 +117,7 @@ protocol PP {
 struct G<each T> {}
 
 // CHECK-LABEL: sameTypeMatch1
-// CHECK-NEXT: <T, each U, each V where T : PP, repeat each U : PP, repeat each V : PP, T.[PP]A == G<repeat (each U).[PP]A>, repeat (each U).[PP]A == (each V).[PP]A>
+// CHECK-NEXT: <T, each U, each V where T : PP, repeat each U : PP, repeat each V : PP, T.[PP]A == G<Pack{repeat (each U).[PP]A}>, repeat (each U).[PP]A == (each V).[PP]A>
 func sameTypeMatch1<T: PP, each U: PP, each V: PP>(t: T, u: repeat each U, v: repeat each V)
   where T.A == G<repeat (each U).A>, T.A == G<repeat (each V).A>,
         (repeat (each U, each V)) : Any {}
diff --git a/test/Generics/protocol_typealias_cycle_5.swift b/test/Generics/protocol_typealias_cycle_5.swift
index 1d35b49f4ae56..c4f736f26fc8f 100644
--- a/test/Generics/protocol_typealias_cycle_5.swift
+++ b/test/Generics/protocol_typealias_cycle_5.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 protocol P : Sequence {
   typealias Element = Iterator.Element
diff --git a/test/Generics/protocol_typealias_unbound_generic.swift b/test/Generics/protocol_typealias_unbound_generic.swift
index 4848cb930f0fe..042737f816c54 100644
--- a/test/Generics/protocol_typealias_unbound_generic.swift
+++ b/test/Generics/protocol_typealias_unbound_generic.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 protocol P {
   typealias A = Array
diff --git a/test/Generics/rdar123013710.swift b/test/Generics/rdar123013710.swift
index 7be2741296367..fc6ad9fcea891 100644
--- a/test/Generics/rdar123013710.swift
+++ b/test/Generics/rdar123013710.swift
@@ -8,9 +8,9 @@ public protocol P {
     static func f() -> Any?
 }
 
-protocol Q: P where B == Never {} // expected-error {{circular reference}}
+protocol Q: P where B == Never {} // expected-error@:10 {{circular reference}}
 
-extension Never: Q, P { // expected-note 2{{through reference here}}
+extension Never: Q, P { // expected-note@:1 {{through reference here}}
    public typealias A = Never
    public static func f() -> Any? { nil }
 }
diff --git a/test/Generics/rdar158774099.swift b/test/Generics/rdar158774099.swift
new file mode 100644
index 0000000000000..d4c824f3a7cb6
--- /dev/null
+++ b/test/Generics/rdar158774099.swift
@@ -0,0 +1,74 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -typecheck -verify \
+// RUN:     %t/View.swift %t/Modifier.swift %t/MyStorage.swift %t/Storage.swift %t/WrappedStorage.swift
+
+//--- Storage.swift
+
+protocol Representable {
+  associatedtype Outputs
+  typealias Context = RepresentableContext<Self>
+}
+
+struct RepresentableContext<R: Representable> {}
+
+struct Inputs<Outputs> {
+}
+
+protocol Storage<Value> {
+  associatedtype Value
+  associatedtype R: Representable
+
+  func body(content: Content) -> Value
+
+  typealias Content = Inputs<R.Outputs>
+}
+
+//--- WrappedStorage.swift
+private struct WrappedStorage<Base: Storage>: Storage where Base.Value == MyStorage.Value {
+  typealias R = Base.R
+
+  init(base: Base, body: @escaping (Base.Value) -> Void) {
+  }
+
+  func body(content: Content) -> Base.Value { fatalError() }
+}
+
+extension Storage where Value == MyStorage.Value {
+  func withStorage(body: @escaping (Value) -> Void) -> some Storage<Value> {
+    WrappedStorage(base: self, body: body)
+  }
+}
+
+//--- MyStorage.swift
+struct MyRepresentable: Representable {
+  struct Outputs {}
+}
+
+struct MyStorage: Storage {
+  typealias R = MyRepresentable
+
+  struct Value: Equatable {}
+
+  func body(content: Content) -> Value {
+    fatalError()
+  }
+}
+
+//--- Modifier.swift
+extension P {
+  func storage(_: some Storage) -> some P { Test() }
+}
+
+//--- View.swift
+protocol P {
+}
+
+struct Test: P {
+}
+
+func test() -> some P {
+  let storage = MyStorage().withStorage { value in }
+  return Test().storage(storage)
+}
diff --git a/test/Generics/rdar90402519.swift b/test/Generics/rdar90402519.swift
index 7e6c848502bc5..efee103dd5917 100644
--- a/test/Generics/rdar90402519.swift
+++ b/test/Generics/rdar90402519.swift
@@ -23,5 +23,5 @@ protocol P1 : P0 where C == G1<I> {
 }
 
 protocol P2 : P1 where C == G2<I> {}
-// expected-error@-1 {{cannot build rewrite system for protocol; concrete nesting limit exceeded}}
+// expected-error@-1 {{cannot build rewrite system for protocol; concrete type nesting limit exceeded}}
 // expected-note@-2 {{failed rewrite rule is [P2:I].[concrete: G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<G<[P2:I]>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>] => [P2:I]}}
diff --git a/test/Generics/rdar94848868.swift b/test/Generics/rdar94848868.swift
index 6d8393552fa74..0902efc76a3be 100644
--- a/test/Generics/rdar94848868.swift
+++ b/test/Generics/rdar94848868.swift
@@ -1,19 +1,23 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // This is too circular to work, but it shouldn't crash.
 
 protocol MyCollectionProtocol: Collection where Iterator == MyCollectionIterator<Self> {}
-// expected-error@-1 {{circular reference}}
+// expected-error@-1:10 {{circular reference}}
 
 struct MyCollectionIterator<MyCollection: MyCollectionProtocol>: IteratorProtocol {
-// expected-note@-1 3{{through reference here}}
+  // expected-note@-1:8 {{through reference here}}
+  // expected-note@-2:66 {{through reference here}}
+  // expected-error@-3 {{type 'MyCollectionIterator<MyCollection>' does not conform to protocol 'IteratorProtocol'}}
+  // expected-note@-4 {{add stubs for conformance}}
     mutating func next() -> MyCollection.Element? {
-// expected-note@-1 2{{through reference here}}
+    // expected-error@-1 {{'Element' is not a member type of type 'MyCollection'}}
         return nil
     }
 }
 
 struct MyCollection: MyCollectionProtocol {
+// expected-error@-1 {{type 'MyCollection' does not conform to protocol 'Collection'}}
     struct Element {}
 
     var startIndex: Int { fatalError() }
diff --git a/test/Generics/tuple-conformances-synthesize-crash.swift b/test/Generics/tuple-conformances-synthesize-crash.swift
new file mode 100644
index 0000000000000..8d4fdfafdfb2f
--- /dev/null
+++ b/test/Generics/tuple-conformances-synthesize-crash.swift
@@ -0,0 +1,5 @@
+// RUN: not %target-swift-frontend -typecheck %s
+
+// Just don't crash.
+extension () : Comparable {}
+
diff --git a/test/Generics/unbound.swift b/test/Generics/unbound.swift
index a634f9e27e72e..d4df3f3c664c0 100644
--- a/test/Generics/unbound.swift
+++ b/test/Generics/unbound.swift
@@ -8,11 +8,11 @@
 // Places where generic arguments are always required
 // --------------------------------------------------
 
-struct Foo<T> { // expected-note 3{{generic type 'Foo' declared here}}
+struct Foo<T> { // expected-note 3{{generic struct 'Foo' declared here}}
   struct Wibble { }
 }
 
-class Dict<K, V> { } // expected-note{{generic type 'Dict' declared here}} expected-note{{generic type 'Dict' declared here}} expected-note{{generic type 'Dict' declared here}}
+class Dict<K, V> { } // expected-note 3 {{generic class 'Dict' declared here}}
 
 // The underlying type of a typealias can only have unbound generic arguments
 // at the top level.
@@ -94,8 +94,8 @@ var innerProperty: Outer.Middle.Inner = makeInner()
 // expected-error@-1 {{reference to generic type 'Outer' requires arguments in <...>}}
 
 // Some nested generic cases
-struct OuterStruct<T> { // expected-note 2{{generic type 'OuterStruct' declared here}}
-  struct InnerStruct<U> {} // expected-note {{generic type 'InnerStruct' declared here}}
+struct OuterStruct<T> { // expected-note 2{{generic struct 'OuterStruct' declared here}}
+  struct InnerStruct<U> {} // expected-note {{generic struct 'InnerStruct' declared here}}
 }
 
 func nested(_: OuterStruct.InnerStruct) {}
@@ -141,7 +141,7 @@ do {
 // https://github.com/apple/swift/issues/60922
 
 enum E<T> {}
-// expected-note@-1 2 {{generic type 'E' declared here}}
+// expected-note@-1 2 {{generic enum 'E' declared here}}
 
 extension E? {}
 // expected-error@-1{{reference to generic type 'E' requires arguments in <...>}}
@@ -149,7 +149,7 @@ extension Optional<E> {}
 // expected-error@-1{{reference to generic type 'E' requires arguments in <...>}}
 
 struct G<T> {}
-// expected-note@-1{{generic type 'G' declared here}}
+// expected-note@-1{{generic struct 'G' declared here}}
 
 extension G? {}
 // expected-error@-1{{reference to generic type 'G' requires arguments in <...>}}
diff --git a/test/Generics/unify_superclass_types_invalid.swift b/test/Generics/unify_superclass_types_invalid.swift
new file mode 100644
index 0000000000000..55e41544b5fdf
--- /dev/null
+++ b/test/Generics/unify_superclass_types_invalid.swift
@@ -0,0 +1,10 @@
+// RUN: %target-typecheck-verify-swift
+// RUN: not %target-swift-frontend -typecheck -debug-generic-signatures %s 2>&1 | %FileCheck %s
+
+class Base<T> {}
+class Derived : Base<Foo> {}
+// expected-error@-1 {{cannot find type 'Foo' in scope}}
+
+// CHECK-LABEL: unify_superclass_types_invalid.(file).f@
+// CHECK: Generic signature: <T where T : Derived>
+func f<T>(_: T) where T: Base<Int>, T: Derived {}
\ No newline at end of file
diff --git a/test/Generics/variadic_generic_types.swift b/test/Generics/variadic_generic_types.swift
index d853743ec2d06..5104d8b0bde6b 100644
--- a/test/Generics/variadic_generic_types.swift
+++ b/test/Generics/variadic_generic_types.swift
@@ -33,7 +33,7 @@ func bindAll() {
 }
 
 func bindPrefix() {
-  struct Bind<Prefix, each U> {} // expected-note {{generic type 'Bind' declared here}}
+  struct Bind<Prefix, each U> {} // expected-note {{generic struct 'Bind' declared here}}
 
   typealias Zero = Bind< > // expected-error {{generic type 'Bind' specialized with too few type parameters (got 0, but expected at least 1)}}
   typealias One = Bind<Int> // OK
@@ -42,7 +42,7 @@ func bindPrefix() {
 }
 
 func bindSuffix() {
-  struct Bind<each U, Suffix> {} // expected-note {{generic type 'Bind' declared here}}
+  struct Bind<each U, Suffix> {} // expected-note {{generic struct 'Bind' declared here}}
 
   typealias Zero = Bind< > // expected-error {{generic type 'Bind' specialized with too few type parameters (got 0, but expected at least 1)}}
   typealias One = Bind<Int> // OK
@@ -51,7 +51,7 @@ func bindSuffix() {
 }
 
 func bindPrefixAndSuffix() {
-  struct Bind<Prefix, each U, Suffix> {} // expected-note 2{{generic type 'Bind' declared here}}
+  struct Bind<Prefix, each U, Suffix> {} // expected-note 2{{generic struct 'Bind' declared here}}
 
   typealias Zero = Bind< > // expected-error {{generic type 'Bind' specialized with too few type parameters (got 0, but expected at least 2)}}
   typealias One = Bind<Int> // expected-error {{generic type 'Bind' specialized with too few type parameters (got 1, but expected at least 2)}}
@@ -70,7 +70,7 @@ func bindAliasAll() {
 }
 
 func bindAliasPrefix() {
-  typealias Bind<Prefix, each U> = (Prefix, repeat each U) // expected-note {{generic type 'Bind' declared here}}
+  typealias Bind<Prefix, each U> = (Prefix, repeat each U) // expected-note {{generic type alias 'Bind' declared here}}
 
   typealias Zero = Bind< > // expected-error {{generic type 'Bind' specialized with too few type parameters (got 0, but expected at least 1)}}
   typealias One = Bind<Int> // OK
@@ -79,7 +79,7 @@ func bindAliasPrefix() {
 }
 
 func bindAliasSuffix() {
-  typealias Bind<each U, Suffix> = (repeat each U, Suffix) // expected-note {{generic type 'Bind' declared here}}
+  typealias Bind<each U, Suffix> = (repeat each U, Suffix) // expected-note {{generic type alias 'Bind' declared here}}
 
   typealias Zero = Bind< > // expected-error {{generic type 'Bind' specialized with too few type parameters (got 0, but expected at least 1)}}
   typealias One = Bind<Int> // OK
@@ -88,7 +88,7 @@ func bindAliasSuffix() {
 }
 
 func bindAliasPrefixAndSuffix() {
-  typealias Bind<Prefix, each U, Suffix> = (Prefix, repeat each U, Suffix) // expected-note 2{{generic type 'Bind' declared here}}
+  typealias Bind<Prefix, each U, Suffix> = (Prefix, repeat each U, Suffix) // expected-note 2{{generic type alias 'Bind' declared here}}
 
   typealias Zero = Bind< > // expected-error {{generic type 'Bind' specialized with too few type parameters (got 0, but expected at least 2)}}
   typealias One = Bind<Int> // expected-error {{generic type 'Bind' specialized with too few type parameters (got 1, but expected at least 2)}}
@@ -98,8 +98,8 @@ func bindAliasPrefixAndSuffix() {
 }
 
 func invalidPackExpansion<each X, each Y, Z>(x: repeat each X, y: repeat each Y, z: Z) {
-  typealias A<T, each U> = (T, repeat each U) // expected-note 4{{generic type 'A' declared here}}
-  typealias B<each T, U> = (repeat each T, U) // expected-note 4{{generic type 'B' declared here}}
+  typealias A<T, each U> = (T, repeat each U) // expected-note 4{{generic type alias 'A' declared here}}
+  typealias B<each T, U> = (repeat each T, U) // expected-note 4{{generic type alias 'B' declared here}}
 
   typealias One = A<repeat each X> // expected-error {{generic type 'A' specialized with mismatched type parameter pack}}
   typealias Two = A<repeat each X, repeat each Y> // expected-error {{generic type 'A' specialized with mismatched type parameter pack}}
@@ -116,3 +116,16 @@ func packExpansionInScalarArgument<each T>(_: repeat each T) {
   typealias A<U> = U
   typealias One = A<repeat each T> // expected-error {{pack expansion 'repeat each T' can only appear in a function parameter list, tuple element, or generic argument of a variadic type}}
 }
+
+// Make sure we diagnose instead of silently dropping the same-type requirement
+// https://github.com/apple/swift/issues/70432
+
+struct WithPack<each T> {}
+
+// FIXME: The diagnostics are misleading.
+
+extension WithPack<Int, Int> {}
+// expected-error@-1 {{same-type requirements between packs and concrete types are not yet supported}}
+
+extension WithPack where (repeat each T) == (Int, Int) {}
+// expected-error@-1 {{generic signature requires types '(repeat each T)' and '(Int, Int)' to be the same}}
\ No newline at end of file
diff --git a/test/Generics/variadic_generic_types_availability.swift b/test/Generics/variadic_generic_types_availability.swift
index acf3048bdd9b1..fea7d534d8bca 100644
--- a/test/Generics/variadic_generic_types_availability.swift
+++ b/test/Generics/variadic_generic_types_availability.swift
@@ -3,7 +3,7 @@
 // REQUIRES: OS=macosx
 
 struct G<each T> {}
-// expected-note@-1 {{add @available attribute to enclosing generic struct}}
+// expected-note@-1 {{add '@available' attribute to enclosing generic struct}}
 // expected-error@-2 {{parameter packs in generic types are only available in macOS 14.0.0 or newer}}
 
 // Type aliases are OK
diff --git a/test/IDE/Inputs/foo_swift_module.printed.comments.txt b/test/IDE/Inputs/foo_swift_module.printed.comments.txt
index 07094ce0d318c..d9b4720778492 100644
--- a/test/IDE/Inputs/foo_swift_module.printed.comments.txt
+++ b/test/IDE/Inputs/foo_swift_module.printed.comments.txt
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 func %%% (lhs: Int, rhs: Int) -> Int
 postfix func =-> (lhs: Int) -> Int
 postfix func => (lhs: Int) -> Int
diff --git a/test/IDE/clang-importing/complete_doc_clang.swift b/test/IDE/clang-importing/complete_doc_clang.swift
new file mode 100644
index 0000000000000..d0d2f3f811b77
--- /dev/null
+++ b/test/IDE/clang-importing/complete_doc_clang.swift
@@ -0,0 +1,30 @@
+// RUN: %target-swift-ide-test(mock-sdk: %clang-importer-sdk) -code-completion -source-filename %s -code-completion-token=TOP -code-completion-comments -code-completion-sort-by-name \
+// RUN:    -import-objc-header %S/Inputs/bridge.h -I %S/Inputs/somemod1 -I %S/Inputs/somemod2 | %FileCheck %s -check-prefix=CHECK-TOP
+// RUN: %target-swift-ide-test(mock-sdk: %clang-importer-sdk) -code-completion -source-filename %s -code-completion-token=TOP -code-completion-comments -code-completion-sort-by-name \
+// RUN:    -import-objc-header %S/Inputs/bridge.h -pch-output-dir %t.pch -I %S/Inputs/somemod1 -I %S/Inputs/somemod2 | %FileCheck %s -check-prefix=CHECK-TOP
+
+// REQUIRES: objc_interop
+
+import somemod2
+
+#^TOP^#
+
+// CHECK-TOP-LABEL: name=some_func11();
+// CHECK-TOP-SAME:  briefcomment=some_func11 is cool function.;
+// CHECK-TOP-SAME:  xmlcomment=<Function file="{{.*}}" line="2" column="6"><Name>some_func11</Name><USR>c:@F@some_func11</USR><Declaration>func some_func11()</Declaration><Abstract><Para> some_func11 is cool function.</Para></Abstract></Function>;
+// CHECK-TOP-SAME:  rawcomment=some_func11 is cool function.
+
+// CHECK-TOP-LABEL: name=some_func12();
+// CHECK-TOP-SAME:  briefcomment=some_func12 is cool function.;
+// CHECK-TOP-SAME:  xmlcomment=<Function file="{{.*}}" line="5" column="6"><Name>some_func12</Name><USR>c:@F@some_func12</USR><Declaration>func some_func12()</Declaration><Abstract><Para> some_func12 is cool function.</Para></Abstract></Function>;
+// CHECK-TOP-SAME:  rawcomment=some_func12 is cool function.
+
+// CHECK-TOP-LABEL: name=some_func21();
+// CHECK-TOP-SAME:  briefcomment=some_func21 is cool function.;
+// CHECK-TOP-SAME:  xmlcomment=<Function file="{{.*}}" line="2" column="6"><Name>some_func21</Name><USR>c:@F@some_func21</USR><Declaration>func some_func21()</Declaration><Abstract><Para> some_func21 is cool function.</Para></Abstract></Function>;
+// CHECK-TOP-SAME:  rawcomment=some_func21 is cool function.
+
+// CHECK-TOP-LABEL: name=some_func22();
+// CHECK-TOP-SAME:  briefcomment=some_func22 is cool function.;
+// CHECK-TOP-SAME:  xmlcomment=<Function file="{{.*}}" line="5" column="6"><Name>some_func22</Name><USR>c:@F@some_func22</USR><Declaration>func some_func22()</Declaration><Abstract><Para> some_func22 is cool function.</Para></Abstract></Function>;
+// CHECK-TOP-SAME:  rawcomment=some_func22 is cool function.
diff --git a/test/IDE/clang-importing/complete_with_clang_comments.swift b/test/IDE/clang-importing/complete_with_clang_comments.swift
deleted file mode 100644
index b3816c05052b1..0000000000000
--- a/test/IDE/clang-importing/complete_with_clang_comments.swift
+++ /dev/null
@@ -1,14 +0,0 @@
-// RUN: %target-swift-ide-test(mock-sdk: %clang-importer-sdk) -code-completion -source-filename %s -code-completion-token=TOP -code-completion-comments=true \
-// RUN:    -import-objc-header %S/Inputs/bridge.h -I %S/Inputs/somemod1 -I %S/Inputs/somemod2 | %FileCheck %s -check-prefix=CHECK-TOP
-// RUN: %target-swift-ide-test(mock-sdk: %clang-importer-sdk) -code-completion -source-filename %s -code-completion-token=TOP -code-completion-comments=true \
-// RUN:    -import-objc-header %S/Inputs/bridge.h -pch-output-dir %t.pch -I %S/Inputs/somemod1 -I %S/Inputs/somemod2 | %FileCheck %s -check-prefix=CHECK-TOP
-
-// REQUIRES: objc_interop
-
-import somemod2
-
-#^TOP^#
-// CHECK-TOP: name=some_func11(); comment=some_func11 is cool function.
-// CHECK-TOP: name=some_func12(); comment=some_func12 is cool function.
-// CHECK-TOP: name=some_func21(); comment=some_func21 is cool function.
-// CHECK-TOP: name=some_func22(); comment=some_func22 is cool function.
diff --git a/test/IDE/complete_after_sself.swift b/test/IDE/complete_after_sself.swift
index 1735541c8ba80..36fe440e5d21b 100644
--- a/test/IDE/complete_after_sself.swift
+++ b/test/IDE/complete_after_sself.swift
@@ -73,8 +73,8 @@ extension MyProto {
     Self.#^SSELF_DOT_IN_STATICMETHOD_MyProto^#
   }
 // CHECK-MyProto: Begin completions, 5 items
-// CHECK-MyProto-DAG: Keyword[self]/CurrNominal:          self[#Self.Type#];
-// CHECK-MyProto-DAG: Keyword/CurrNominal:                Type[#Self.Type#];
+// CHECK-MyProto-DAG: Keyword[self]/CurrNominal:          self[#MyProto.Type#];
+// CHECK-MyProto-DAG: Keyword/CurrNominal:                Type[#MyProto.Type#];
 // CHECK-MyProto-DAG: Decl[Constructor]/CurrNominal:      init()[#MyProto#];
 // CHECK-MyProto-DAG: Decl[InstanceMethod]/CurrNominal:   instanceMethod({#(self): MyProto#})[#() -> Void#];
 // CHECK-MyProto-DAG: Decl[StaticMethod]/CurrNominal:     staticMethod()[#Void#];
diff --git a/test/IDE/complete_ambiguous.swift b/test/IDE/complete_ambiguous.swift
index 425c262ca4116..39e3bf8502112 100644
--- a/test/IDE/complete_ambiguous.swift
+++ b/test/IDE/complete_ambiguous.swift
@@ -34,7 +34,7 @@ arrayWrapper(overloadedReturn()).#^SKIP_DUPLICATES^#
 // SKIP_DUPLICATES-NOT: count[#Int#]
 // SKIP_DUPLICATES-NOT: formIndex({#(i): &Int#}, {#offsetBy: Int#})[#Void#]
 
-let x: (inout Int, Int) -> () = arrayWrapper(overloadedReturn()).#^SKIP_COMPOUND_DUPLICATES^#
+let x1: (inout Int, Int) -> () = arrayWrapper(overloadedReturn()).#^SKIP_COMPOUND_DUPLICATES^#
 
 // SKIP_COMPOUND_DUPLICATES: Decl[InstanceMethod]/Super/IsSystem/TypeRelation[Convertible]: formIndex(_:offsetBy:)[#(inout Int, Int) -> ()#]{{; name=.+$}}
 // SKIP_COMPOUND_DUPLICATES-NOT: formIndex(_:offsetBy:)[#(inout Int, Int) -> ()#]
@@ -62,8 +62,8 @@ givenErrorExpr(undefined).#^ERROR_IN_BASE?check=SIMPLE^#
 // SIMPLE-DAG: Keyword[self]/CurrNominal:          self[#B#]{{; name=.+$}}
 // SIMPLE-DAG: Decl[InstanceMethod]/CurrNominal:   doBThings()[#Void#]{{; name=.+$}}
 
-let x: A = overloadedReturn().#^RELATED^#
-let x: A = overloadedReturn(1).#^RELATED_EXTRAARG?check=RELATED^#
+let x2: A = overloadedReturn().#^RELATED^#
+let x3: A = overloadedReturn(1).#^RELATED_EXTRAARG?check=RELATED^#
 
 // RELATED: Begin completions, 4 items
 // RELATED-DAG: Keyword[self]/CurrNominal:          self[#A#]{{; name=.+$}}
diff --git a/test/IDE/complete_at_top_level.swift b/test/IDE/complete_at_top_level.swift
index 8ae4eba3a0ad3..8aa7088fbedc3 100644
--- a/test/IDE/complete_at_top_level.swift
+++ b/test/IDE/complete_at_top_level.swift
@@ -79,7 +79,7 @@ func resyncParser6() {}
 
 fooObject.instanceFunc(#^TYPE_CHECKED_EXPR_6?check=PLAIN_TOP_LEVEL^#
 
-func resyncParser6() {}
+func resyncParser6b() {}
 
 fooObject.is#^TYPE_CHECKED_EXPR_KW_1?check=NORESULT^#
 
@@ -104,7 +104,7 @@ var topLevelVar1 = #^TOP_LEVEL_VAR_INIT_1?check=TOP_LEVEL_VAR_INIT_1;check=TOP_L
 // Check that the variable itself does not show up.
 // TOP_LEVEL_VAR_INIT_1_NEGATIVE-NOT: topLevelVar1
 
-func resyncParser7() {}
+func resyncParser7a() {}
 
 var topLevelVar2 = FooStruct#^TOP_LEVEL_VAR_INIT_2^#
 // TOP_LEVEL_VAR_INIT_2-DAG: Decl[InstanceMethod]/CurrNominal: .instanceFunc({#(self): FooStruct#})[#(Int) -> Void#]{{; name=.+$}}
@@ -213,7 +213,7 @@ func resyncParserB5() {}
 
 for var i = 0; ; {
   #^TOP_LEVEL_STMT_5?check=PLAIN_TOP_LEVEL;check=TOP_LEVEL_STMT_5^#
-// TOP_LEVEL_STMT_5: Decl[LocalVar]/Local: i[#<<error type>>#]{{; name=.+$}}
+// TOP_LEVEL_STMT_5: Decl[LocalVar]/Local: i[#_#]{{; name=.+$}}
 }
 
 func resyncParserB6() {}
@@ -234,7 +234,7 @@ func resyncParserB8() {}
 
 for i in unknown_var {
   #^TOP_LEVEL_STMT_8?check=PLAIN_TOP_LEVEL;check=TOP_LEVEL_STMT_8^#
-// TOP_LEVEL_STMT_8: Decl[LocalVar]/Local: i[#<<error type>>#]{{; name=.+$}}
+// TOP_LEVEL_STMT_8: Decl[LocalVar]/Local: i[#_#]{{; name=.+$}}
 }
 
 func resyncParserB9() {}
@@ -295,10 +295,10 @@ func resyncParserB14() {}
 var stringInterp = "\(#^STRING_INTERP_3?check=STRING_INTERP^#)"
 _ = "" + "\(#^STRING_INTERP_4?check=STRING_INTERP^#)" + ""
 // STRING_INTERP-DAG: Decl[InstanceMethod]/CurrNominal/Flair[ArgLabels]/IsSystem: ['(']{#(value): any Any.Type#}[')'][#Void#];
-// STRING_INTERP-DAG: Decl[Struct]/CurrModule: FooStruct[#FooStruct#]; name=FooStruct
-// STRING_INTERP-DAG: Decl[FreeFunction]/CurrModule/TypeRelation[Invalid]: fooFunc1()[#Void#];
-// STRING_INTERP-DAG: Decl[FreeFunction]/CurrModule: optStr()[#String?#];
-// STRING_INTERP-DAG: Decl[GlobalVar]/Local: fooObject[#FooStruct#];
+// STRING_INTERP-DAG: Decl[Struct]/CurrModule/TypeRelation[Convertible]: FooStruct[#FooStruct#]; name=FooStruct
+// STRING_INTERP-DAG: Decl[FreeFunction]/CurrModule/TypeRelation[Convertible]: fooFunc1[#() -> ()#]; name=fooFunc1
+// STRING_INTERP-DAG: Decl[FreeFunction]/CurrModule/TypeRelation[Convertible]: optStr()[#String?#]; name=optStr()
+// STRING_INTERP-DAG: Decl[GlobalVar]/Local/TypeRelation[Convertible]: fooObject[#FooStruct#]; name=fooObject
 func resyncParserC1() {}
 
 // FOR_COLLECTION-NOT: forIndex
diff --git a/test/IDE/complete_cache_notrecommended.swift b/test/IDE/complete_cache_notrecommended.swift
index 97d807a8d104e..9d66c6c20cb3c 100644
--- a/test/IDE/complete_cache_notrecommended.swift
+++ b/test/IDE/complete_cache_notrecommended.swift
@@ -32,11 +32,13 @@ func testAsync() async -> Int {
 }
 func testSyncMember(obj: MyActor) -> Int {
     obj.#^MEMBER_IN_SYNC^#
-// MEMBER_IN_SYNC: Begin completions, 9 items
+// MEMBER_IN_SYNC: Begin completions, 11 items
 // MEMBER_IN_SYNC-DAG: Keyword[self]/CurrNominal:          self[#MyActor#];
 // MEMBER_IN_SYNC-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: actorMethod()[' async'][#Int#];
 // MEMBER_IN_SYNC-DAG: Decl[InstanceMethod]/CurrNominal/NotRecommended: deprecatedMethod()[' async'][#Void#];
 // MEMBER_IN_SYNC-DAG: Decl[InstanceVar]/CurrNominal:      unownedExecutor[#UnownedSerialExecutor#];
+// MEMBER_IN_SYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: withSerialExecutor({#(operation): (any SerialExecutor) throws(Error) -> ~Copyable##(any SerialExecutor) throws(Error) -> ~Copyable#})[' throws'][#~Copyable#]; name=withSerialExecutor(:)
+// MEMBER_IN_SYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: withSerialExecutor({#(operation): (any SerialExecutor) async throws(Error) -> ~Copyable##(any SerialExecutor) async throws(Error) -> ~Copyable#})[' async'][' throws'][#~Copyable#]; name=withSerialExecutor(:)
 // MEMBER_IN_SYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: preconditionIsolated()[#Void#]; name=preconditionIsolated()
 // MEMBER_IN_SYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: preconditionIsolated({#(message): String#})[#Void#]; name=preconditionIsolated(:)
 // MEMBER_IN_SYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: assertIsolated()[#Void#]; name=assertIsolated()
@@ -46,11 +48,13 @@ func testSyncMember(obj: MyActor) -> Int {
 
 func testSyncMember(obj: MyActor) async -> Int {
     obj.#^MEMBER_IN_ASYNC^#
-// MEMBER_IN_ASYNC: Begin completions, 9 items
+// MEMBER_IN_ASYNC: Begin completions, 11 items
 // MEMBER_IN_ASYNC-DAG: Keyword[self]/CurrNominal:          self[#MyActor#];
 // MEMBER_IN_ASYNC-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: actorMethod()[' async'][#Int#];
 // MEMBER_IN_ASYNC-DAG: Decl[InstanceMethod]/CurrNominal/NotRecommended: deprecatedMethod()[' async'][#Void#];
 // MEMBER_IN_ASYNC-DAG: Decl[InstanceVar]/CurrNominal:      unownedExecutor[#UnownedSerialExecutor#];
+// MEMBER_IN_ASYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: withSerialExecutor({#(operation): (any SerialExecutor) throws(Error) -> ~Copyable##(any SerialExecutor) throws(Error) -> ~Copyable#})[' throws'][#~Copyable#]; name=withSerialExecutor(:)
+// MEMBER_IN_ASYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: withSerialExecutor({#(operation): (any SerialExecutor) async throws(Error) -> ~Copyable##(any SerialExecutor) async throws(Error) -> ~Copyable#})[' async'][' throws'][#~Copyable#]; name=withSerialExecutor(:)
 // MEMBER_IN_ASYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: preconditionIsolated()[#Void#]; name=preconditionIsolated()
 // MEMBER_IN_ASYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: preconditionIsolated({#(message): String#})[#Void#]; name=preconditionIsolated(:)
 // MEMBER_IN_ASYNC-DAG: Decl[InstanceMethod]/Super/IsSystem: assertIsolated()[#Void#]; name=assertIsolated()
diff --git a/test/IDE/complete_call_arg.swift b/test/IDE/complete_call_arg.swift
index 940251964974d..cb3722aaf43bb 100644
--- a/test/IDE/complete_call_arg.swift
+++ b/test/IDE/complete_call_arg.swift
@@ -1443,3 +1443,14 @@ struct NestedCallsWithoutClosingParen {
     _ = (foo(#^IN_TUPLE?check=NESTED_CALL_WITHOUT_TYPE_RELATION^#, 1)
   }
 }
+
+func testUnboundContextualType() {
+  struct S<T> {
+    func bar(x: Int) -> Self { self }
+  }
+
+  func foo(x: S<Int>) {
+    let _: S = x.bar(#^ARG_WITH_UNBOUND_CONTEXTUAL_TY^#
+    // ARG_WITH_UNBOUND_CONTEXTUAL_TY: Decl[InstanceMethod]/CurrNominal/Flair[ArgLabels]: ['(']{#x: Int#}[')'][#S<Int>#]; name=x:
+  }
+}
diff --git a/test/IDE/complete_call_pattern.swift b/test/IDE/complete_call_pattern.swift
index e0853123bd0da..8625f98210f67 100644
--- a/test/IDE/complete_call_pattern.swift
+++ b/test/IDE/complete_call_pattern.swift
@@ -81,12 +81,10 @@ struct AmbiguousInResultBuilder {
 
   func test(myStr: String) {
     foo {
-      Text(#^AMBIGUOUS_IN_RESULT_BUILDER?xfail=TODO^#)
-// AMBIGUOUS_IN_RESULT_BUILDER: Begin completions
+      Text(#^AMBIGUOUS_IN_RESULT_BUILDER^#)
 // AMBIGUOUS_IN_RESULT_BUILDER-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]: ['(']{#verbatim: String#}[')'][#Text#]; name=verbatim:
-// AMBIGUOUS_IN_RESULT_BUILDER-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]: ['(']{#(content): _#}[')'][#Text#]; name=:
+// AMBIGUOUS_IN_RESULT_BUILDER-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]: ['(']{#(content): StringProtocol#}[')'][#Text#]; name=:
 // AMBIGUOUS_IN_RESULT_BUILDER-DAG: Decl[LocalVar]/Local/TypeRelation[Convertible]: myStr[#String#]; name=myStr
-// AMBIGUOUS_IN_RESULT_BUILDER: End completions
     }
   }
 }
diff --git a/test/IDE/complete_closure_ambiguity.swift b/test/IDE/complete_closure_ambiguity.swift
new file mode 100644
index 0000000000000..a1daa7be26079
--- /dev/null
+++ b/test/IDE/complete_closure_ambiguity.swift
@@ -0,0 +1,31 @@
+// RUN: %empty-directory(%t)
+// RUN: %batch-code-completion -debug-constraints 2> %t/constraints.log
+// RUN: %FileCheck %s -check-prefix CONSTRAINTS < %t/constraints.log
+// RUN: %FileCheck %s -check-prefix CONSTRAINTS-NOT < %t/constraints.log
+
+protocol P1 {}
+protocol P2 {}
+
+func foo<T: P1>(_ fn: () -> T) {}
+
+@_disfavoredOverload
+func foo<T: P2>(_ fn: () -> T) {}
+
+func bar(_ x: Int) -> Int {}
+func bar(_ x: String) -> String {}
+
+// Make sure we eagerly prune the disfavored overload of 'foo', despite the
+// ambiguity in the closure body.
+foo {
+  let x = bar(#^COMPLETE^#)
+  // COMPLETE: Decl[FreeFunction]/CurrModule/Flair[ArgLabels]: ['(']{#(x): Int#}[')'][#Int#]; name=:
+  // COMPLETE: Decl[FreeFunction]/CurrModule/Flair[ArgLabels]: ['(']{#(x): String#}[')'][#String#]; name=:
+
+  return x
+}
+
+// CONSTRAINTS: attempting disjunction choice {{.*}}:12:6
+// CONSTRAINTS: increasing 'disfavored overload' score
+// CONSTRAINTS: solution is worse than the best solution
+
+// CONSTRAINTS-NOT-NOT: increasing 'hole'
diff --git a/test/IDE/complete_constructor.swift b/test/IDE/complete_constructor.swift
index 9f810eb23681f..fa7d708f9614c 100644
--- a/test/IDE/complete_constructor.swift
+++ b/test/IDE/complete_constructor.swift
@@ -315,15 +315,15 @@ func testDependentTypeInClosure() {
 // DEPENDENT_IN_CLOSURE_3-DAG: Decl[Constructor]/CurrNominal/TypeRelation[Convertible]: init({#arg: DataType#}, {#fn: () -> Data.Content##() -> Data.Content#})[#DependentTypeInClosure<DataType>#];
 
   let _ = DependentTypeInClosure(#^DEPENDENT_IN_CLOSURE_1^#)
-// DEPENDENT_IN_CLOSURE_1-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#(arg): DataType#}, {#fn: (_) -> Void##(_) -> Void#}[')'][#DependentTypeInClosure<DataType>#];
-// DEPENDENT_IN_CLOSURE_1-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#arg: DataType#}, {#fn: () -> _##() -> _#}[')'][#DependentTypeInClosure<DataType>#];
+// DEPENDENT_IN_CLOSURE_1-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#(arg): DataType#}, {#fn: (Data.Content) -> Void##(Data.Content) -> Void#}[')'][#DependentTypeInClosure<DataType>#];
+// DEPENDENT_IN_CLOSURE_1-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#arg: DataType#}, {#fn: () -> Data.Content##() -> Data.Content#}[')'][#DependentTypeInClosure<DataType>#];
 
   let _ = DependentTypeInClosure.#^DEPENDENT_IN_CLOSURE_2^#
 // DEPENDENT_IN_CLOSURE_2: Begin completions, 4 items
-// DEPENDENT_IN_CLOSURE_2-DAG: Keyword[self]/CurrNominal:          self[#DependentTypeInClosure<_>.Type#]; name=self
-// DEPENDENT_IN_CLOSURE_2-DAG: Keyword/CurrNominal:                Type[#DependentTypeInClosure<_>.Type#]; name=Type
-// DEPENDENT_IN_CLOSURE_2-DAG: Decl[Constructor]/CurrNominal:      init({#(arg): _#}, {#fn: (_.Content) -> Void##(_.Content) -> Void#})[#DependentTypeInClosure<_>#]; name=init(:fn:)
-// DEPENDENT_IN_CLOSURE_2-DAG: Decl[Constructor]/CurrNominal:      init({#arg: _#}, {#fn: () -> _.Content##() -> _.Content#})[#DependentTypeInClosure<_>#]; name=init(arg:fn:)
+// DEPENDENT_IN_CLOSURE_2-DAG: Keyword[self]/CurrNominal:          self[#DependentTypeInClosure<Data>.Type#]; name=self
+// DEPENDENT_IN_CLOSURE_2-DAG: Keyword/CurrNominal:                Type[#DependentTypeInClosure<Data>.Type#]; name=Type
+// DEPENDENT_IN_CLOSURE_2-DAG: Decl[Constructor]/CurrNominal:      init({#(arg): Data#}, {#fn: (Data.Content) -> Void##(Data.Content) -> Void#})[#DependentTypeInClosure<Data>#]; name=init(:fn:)
+// DEPENDENT_IN_CLOSURE_2-DAG: Decl[Constructor]/CurrNominal:      init({#arg: Data#}, {#fn: () -> Data.Content##() -> Data.Content#})[#DependentTypeInClosure<Data>#]; name=init(arg:fn:)
 }
 struct InitWithUnresolved<Data: DataType> where Data.Content: Comparable {
   init(arg: Data, fn: (Data.Content) -> Void) {}
@@ -334,7 +334,7 @@ extension InitWithUnresolved where Self.Data: Comparable {
 func testInitWithUnresolved() {
   let _ = InitWithUnresolved(#^INIT_WITH_UNRESOLVEDTYPE_1^#
 // INIT_WITH_UNRESOLVEDTYPE_1: Begin completions, 2 items
-// INIT_WITH_UNRESOLVEDTYPE_1-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#arg: DataType#}, {#fn: (_) -> Void##(_) -> Void#}[')'][#InitWithUnresolved<DataType>#];
+// INIT_WITH_UNRESOLVEDTYPE_1-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#arg: DataType#}, {#fn: (Data.Content) -> Void##(Data.Content) -> Void#}[')'][#InitWithUnresolved<DataType>#];
 // INIT_WITH_UNRESOLVEDTYPE_1-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#arg2: DataType#}[')'][#InitWithUnresolved<DataType>#];
 }
 
diff --git a/test/IDE/complete_crashes.swift b/test/IDE/complete_crashes.swift
index 509f50121dbe2..19603004d9ec6 100644
--- a/test/IDE/complete_crashes.swift
+++ b/test/IDE/complete_crashes.swift
@@ -38,7 +38,7 @@ func globalFunc() {}
 func globalFuncInt() -> Int { return 0 }
 
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=LET_COMPUTED | %FileCheck %s -check-prefix=WITH_GLOBAL
-class C {
+class C1 {
   let x : Int { #^LET_COMPUTED^# }
 }
 
@@ -85,7 +85,7 @@ private protocol RoundRobin : Sendable, Receivable {
 
 // rdar://problem/21435993
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=RDAR_21435993
-class C<T> {
+class C2<T> {
   func test() {
     do {} catch { #^RDAR_21435993^# }
   }
@@ -381,6 +381,6 @@ extension P_80635105 {
 func test_80635105() {
   let fn = { x in
     S_80635105.#^RDAR_80635105^#
-    // RDAR_80635105: Decl[InstanceMethod]/Super: foo({#(self): S_80635105<_>#})[#(P_80635105.T) -> Void#]; name=foo
+    // RDAR_80635105: Decl[InstanceMethod]/Super: foo({#(self): S_80635105<T>#})[#(P_80635105.T) -> Void#]; name=foo
   }
 }
diff --git a/test/IDE/complete_decl_attribute.swift b/test/IDE/complete_decl_attribute.swift
index 6cf7505401f2c..9082ed637fd86 100644
--- a/test/IDE/complete_decl_attribute.swift
+++ b/test/IDE/complete_decl_attribute.swift
@@ -19,6 +19,11 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=KEYWORD_INDEPENDENT_2 | %FileCheck %s -check-prefix=KEYWORD_LAST
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=KEYWORD_LAST | %FileCheck %s -check-prefix=KEYWORD_LAST
 
+// NOTE: If you want to test code completion for an experimental feature, please
+// put your tests in complete_decl_attribute_feature_requirement.swift, not
+// here. That file has the infrastructure to test that completions are not
+// offered when the feature is disabled.
+
 struct MyStruct {}
 
 @propertyWrapper
@@ -78,6 +83,7 @@ actor MyGenericGlobalActor<T> {
 // AVAILABILITY1-NEXT: Keyword/None:                       macOSApplicationExtension[#Platform#]; name=macOSApplicationExtension{{$}}
 // AVAILABILITY1-NEXT: Keyword/None:                       macCatalyst[#Platform#]; name=macCatalyst
 // AVAILABILITY1-NEXT: Keyword/None:                       macCatalystApplicationExtension[#Platform#]; name=macCatalystApplicationExtension
+// AVAILABILITY1-NEXT: Keyword/None:                       FreeBSD[#Platform#]; name=FreeBSD{{$}}
 // AVAILABILITY1-NEXT: Keyword/None:                       OpenBSD[#Platform#]; name=OpenBSD{{$}}
 // AVAILABILITY1-NEXT: Keyword/None:                       Windows[#Platform#]; name=Windows{{$}}
 
@@ -111,7 +117,10 @@ actor MyGenericGlobalActor<T> {
 // KEYWORD2-NEXT:             Keyword/None:                       Sendable[#Func Attribute#]; name=Sendable
 // KEYWORD2-NEXT:             Keyword/None:                       preconcurrency[#Func Attribute#]; name=preconcurrency
 // KEYWORD2-NEXT:             Keyword/None:                       backDeployed[#Func Attribute#]; name=backDeployed
-// KEYWORD2-NEXT              Keyword/None:                       lifetime[#Func Attribute#]; name=lifetime
+// KEYWORD2-NEXT:             Keyword/None:                       lifetime[#Func Attribute#]; name=lifetime
+// KEYWORD2-NEXT:             Keyword/None:                       abi[#Func Attribute#]; name=abi{{$}}
+// KEYWORD2-NEXT:             Keyword/None:                       concurrent[#Func Attribute#]; name=concurrent
+// KEYWORD2-NOT:              Keyword
 // KEYWORD2-DAG:              Decl[Struct]/CurrModule:            MyStruct[#MyStruct#]; name=MyStruct
 // KEYWORD2-DAG:              Decl[Struct]/CurrModule:            MyPropertyWrapper[#Property Wrapper#]; name=MyPropertyWrapper
 // KEYWORD2-DAG:              Decl[Struct]/CurrModule/TypeRelation[Convertible]: MyResultBuilder[#Result Builder#]; name=MyResultBuilder
@@ -167,6 +176,7 @@ actor MyGenericGlobalActor<T> {
 // KEYWORD5-NEXT:             Keyword/None:                       preconcurrency[#Struct Attribute#]; name=preconcurrency
 
 @#^ON_GLOBALVAR^# var globalVar
+// ON_GLOBALVAR-DAG: Keyword/None:                       abi[#Var Attribute#]; name=abi
 // ON_GLOBALVAR-DAG: Keyword/None:                       available[#Var Attribute#]; name=available
 // ON_GLOBALVAR-DAG: Keyword/None:                       objc[#Var Attribute#]; name=objc
 // ON_GLOBALVAR-DAG: Keyword/None:                       NSCopying[#Var Attribute#]; name=NSCopying
@@ -183,6 +193,7 @@ actor MyGenericGlobalActor<T> {
 // ON_GLOBALVAR-DAG: Keyword/None:                       exclusivity[#Var Attribute#]; name=exclusivity
 // ON_GLOBALVAR-DAG: Keyword/None:                       preconcurrency[#Var Attribute#]; name=preconcurrency
 // ON_GLOBALVAR-DAG: Keyword/None:                       backDeployed[#Var Attribute#]; name=backDeployed
+// ON_GLOBALVAR-DAG: Keyword/None:                       concurrent[#Var Attribute#]; name=concurrent
 // ON_GLOBALVAR-NOT: Keyword
 // ON_GLOBALVAR-DAG: Decl[Struct]/CurrModule:            MyStruct[#MyStruct#]; name=MyStruct
 // ON_GLOBALVAR-DAG: Decl[Struct]/CurrModule/TypeRelation[Convertible]: MyPropertyWrapper[#Property Wrapper#]; name=MyPropertyWrapper
@@ -194,6 +205,7 @@ actor MyGenericGlobalActor<T> {
 
 struct _S {
   @#^ON_INIT^# init()
+// ON_INIT-DAG: Keyword/None:                       abi[#Constructor Attribute#]; name=abi
 // ON_INIT-DAG: Keyword/None:                       available[#Constructor Attribute#]; name=available
 // ON_INIT-DAG: Keyword/None:                       objc[#Constructor Attribute#]; name=objc
 // ON_INIT-DAG: Keyword/None:                       inline[#Constructor Attribute#]; name=inline
@@ -204,6 +216,7 @@ struct _S {
 // ON_INIT-DAG: Keyword/None:                       preconcurrency[#Constructor Attribute#]; name=preconcurrency
 
   @#^ON_PROPERTY^# var foo
+// ON_PROPERTY-DAG: Keyword/None:                       abi[#Var Attribute#]; name=abi
 // ON_PROPERTY-DAG: Keyword/None:                       available[#Var Attribute#]; name=available
 // ON_PROPERTY-DAG: Keyword/None:                       objc[#Var Attribute#]; name=objc
 // ON_PROPERTY-DAG: Keyword/None:                       NSCopying[#Var Attribute#]; name=NSCopying
@@ -220,6 +233,7 @@ struct _S {
 // ON_PROPERTY-DAG: Keyword/None:                       exclusivity[#Var Attribute#]; name=exclusivity
 // ON_PROPERTY-DAG: Keyword/None:                       preconcurrency[#Var Attribute#]; name=preconcurrency
 // ON_PROPERTY-DAG: Keyword/None:                       backDeployed[#Var Attribute#]; name=backDeployed
+// ON_PROPERTY-DAG: Keyword/None:                       concurrent[#Var Attribute#]; name=concurrent
 // ON_PROPERTY-NOT: Keyword
 // ON_PROPERTY-DAG: Decl[Struct]/CurrModule:            MyStruct[#MyStruct#]; name=MyStruct
 // ON_PROPERTY-DAG: Decl[Struct]/CurrModule/TypeRelation[Convertible]: MyPropertyWrapper[#Property Wrapper#]; name=MyPropertyWrapper
@@ -230,8 +244,12 @@ struct _S {
 // ON_PROPERTY-DAG: Decl[Actor]/CurrModule/TypeRelation[Convertible]: MyGenericGlobalActor[#Global Actor#]; name=MyGenericGlobalActor
 // ON_PROPERTY-NOT: Decl[PrecedenceGroup]
 
+  @#^ON_SUBSCR^# subscript
+// ON_SUBSCR-DAG:  Keyword/None:                        abi[#Declaration Attribute#]; name=abi
+
   @#^ON_METHOD^# private
   func foo()
+// ON_METHOD-DAG: Keyword/None:                       abi[#Func Attribute#]; name=abi
 // ON_METHOD-DAG: Keyword/None:                       available[#Func Attribute#]; name=available
 // ON_METHOD-DAG: Keyword/None:                       objc[#Func Attribute#]; name=objc
 // ON_METHOD-DAG: Keyword/None:                       IBAction[#Func Attribute#]; name=IBAction
@@ -251,6 +269,7 @@ struct _S {
 // ON_METHOD-DAG: Keyword/None:                       preconcurrency[#Func Attribute#]; name=preconcurrency
 // ON_METHOD-DAG: Keyword/None:                       backDeployed[#Func Attribute#]; name=backDeployed
 // ON_METHOD-DAG: Keyword/None:                       lifetime[#Func Attribute#]; name=lifetime
+// ON_METHOD-DAG: Keyword/None:                       concurrent[#Func Attribute#]; name=concurrent
 // ON_METHOD-NOT: Keyword
 // ON_METHOD-DAG: Decl[Struct]/CurrModule:            MyStruct[#MyStruct#]; name=MyStruct
 // ON_METHOD-DAG: Decl[Struct]/CurrModule:            MyPropertyWrapper[#Property Wrapper#]; name=MyPropertyWrapper
@@ -288,6 +307,7 @@ struct _S {
 
 
   @#^ON_MEMBER_LAST^#
+// ON_MEMBER_LAST-DAG: Keyword/None:                       abi[#Declaration Attribute#]; name=abi
 // ON_MEMBER_LAST-DAG: Keyword/None:                       available[#Declaration Attribute#]; name=available
 // ON_MEMBER_LAST-DAG: Keyword/None:                       objc[#Declaration Attribute#]; name=objc
 // ON_MEMBER_LAST-DAG: Keyword/None:                       dynamicCallable[#Declaration Attribute#]; name=dynamicCallable
@@ -325,6 +345,7 @@ struct _S {
 // ON_MEMBER_LAST-DAG: Keyword/None:                       freestanding[#Declaration Attribute#]; name=freestanding
 // ON_MEMBER_LAST-DAG: Keyword/None:                       storageRestrictions[#Declaration Attribute#]; name=storageRestrictions
 // ON_MEMBER_LAST-DAG: Keyword/None:                       lifetime[#Declaration Attribute#]; name=lifetime
+// ON_MEMBER_LAST-DAG: Keyword/None:                       concurrent[#Declaration Attribute#]; name=concurrent
 // ON_MEMBER_LAST-NOT: Keyword
 // ON_MEMBER_LAST-DAG: Decl[Struct]/CurrModule:            MyStruct[#MyStruct#]; name=MyStruct
 // ON_MEMBER_LAST-DAG: Decl[Struct]/CurrModule/TypeRelation[Convertible]: MyPropertyWrapper[#Property Wrapper#]; name=MyPropertyWrapper
@@ -341,6 +362,8 @@ func takeClosure(_: () -> Void) {
     print("x")
   }
 }
+// FIXME: Not valid in this position (but CompletionLookup can't tell that)
+// IN_CLOSURE-DAG:  Keyword/None:              abi[#Declaration Attribute#]; name=abi
 // FIXME: We should mark MyPropertyWrapper and MyResultBuilder as Unrelated
 // IN_CLOSURE-DAG: Decl[Struct]/CurrModule: MyStruct[#MyStruct#]; name=MyStruct
 // IN_CLOSURE-DAG: Decl[Struct]/CurrModule/TypeRelation[Convertible]: MyPropertyWrapper[#Property Wrapper#]; name=MyPropertyWrapper
@@ -359,6 +382,7 @@ func dummy2() {}
 
 @#^KEYWORD_LAST^#
 
+// KEYWORD_LAST-DAG: Keyword/None:                       abi[#Declaration Attribute#]; name=abi
 // KEYWORD_LAST-DAG: Keyword/None:                       available[#Declaration Attribute#]; name=available{{$}}
 // KEYWORD_LAST-DAG: Keyword/None:                       freestanding[#Declaration Attribute#]; name=freestanding{{$}}
 // KEYWORD_LAST-DAG: Keyword/None:                       objc[#Declaration Attribute#]; name=objc{{$}}
@@ -397,6 +421,7 @@ func dummy2() {}
 // KEYWORD_LAST-DAG: Keyword/None:                       attached[#Declaration Attribute#]; name=attached
 // KEYWORD_LAST-DAG: Keyword/None:                       storageRestrictions[#Declaration Attribute#]; name=storageRestrictions
 // KEYWORD_LAST-DAG: Keyword/None:                       lifetime[#Declaration Attribute#]; name=lifetime
+// KEYWORD_LAST-DAG: Keyword/None:                       concurrent[#Declaration Attribute#]; name=concurrent
 // KEYWORD_LAST-NOT: Keyword
 // KEYWORD_LAST-DAG: Decl[Struct]/CurrModule:            MyStruct[#MyStruct#]; name=MyStruct
 // KEYWORD_LAST-DAG: Decl[Struct]/CurrModule/TypeRelation[Convertible]: MyGenericPropertyWrapper[#Property Wrapper#]; name=MyGenericPropertyWrapper
diff --git a/test/IDE/complete_decl_attribute_feature_requirement.swift b/test/IDE/complete_decl_attribute_feature_requirement.swift
index 8fabadd74d3f1..5332d1f693d13 100644
--- a/test/IDE/complete_decl_attribute_feature_requirement.swift
+++ b/test/IDE/complete_decl_attribute_feature_requirement.swift
@@ -3,158 +3,15 @@
 // it's enabled. When a feature becomes non-experimental, move its test cases
 // into the normal complete_decl_attribute.swift test file.
 
-// REQUIRES: asserts
-
 // RUN: %batch-code-completion -filecheck-additional-suffix _DISABLED
-// RUN: %batch-code-completion -filecheck-additional-suffix _ENABLED \
-// RUN:        -enable-experimental-feature ABIAttribute \
-// RUN:        -enable-experimental-feature ExecutionAttribute
+// RUN: %batch-code-completion -filecheck-additional-suffix _ENABLED
+
+// NOTE: There are currently no experimental features that need code completion
+// testing, but this test file is being left in place for when it's needed
+// again. At that time, please remove the ABIAttribute tests.
+// REQUIRES: new_use_case
 
 // NOTE: Please do not include the ", N items" after "Begin completions". The
 // item count creates needless merge conflicts given that an "End completions"
 // line exists for each test.
 
-@#^KEYWORD2^# func method(){}
-
-// KEYWORD2:              Begin completions
-// KEYWORD2_ENABLED-DAG:  Keyword/None:              abi[#Func Attribute#]; name=abi
-// KEYWORD2_ENABLED-DAG:  Keyword/None:              execution[#Func Attribute#]; name=execution
-// KEYWORD2_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// KEYWORD2_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// KEYWORD2:              End completions
-
-@#^KEYWORD3^# class C {}
-
-// KEYWORD3:              Begin completions
-// KEYWORD3_ENABLED-NOT:  Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// KEYWORD3_ENABLED-NOT:  Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// KEYWORD3_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// KEYWORD3_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// KEYWORD3:              End completions
-
-@#^KEYWORD3_2?check=KEYWORD3^#IB class C2 {}
-// Same as KEYWORD3.
-
-@#^KEYWORD4^# enum E {}
-// KEYWORD4:              Begin completions
-// KEYWORD4_ENABLED-NOT:  Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// KEYWORD4_ENABLED-NOT:  Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// KEYWORD4_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// KEYWORD4_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// KEYWORD4:              End completions
-
-@#^KEYWORD5^# struct S{}
-// KEYWORD5:              Begin completions
-// KEYWORD5_ENABLED-NOT:  Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// KEYWORD5_ENABLED-NOT:  Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// KEYWORD5_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// KEYWORD5_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// KEYWORD5:              End completions
-
-@#^ON_GLOBALVAR^# var globalVar
-// ON_GLOBALVAR:              Begin completions
-// ON_GLOBALVAR_ENABLED-DAG:  Keyword/None:              abi[#Var Attribute#]; name=abi
-// ON_GLOBALVAR_ENABLED-DAG:  Keyword/None:              execution[#Var Attribute#]; name=execution
-// ON_GLOBALVAR_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// ON_GLOBALVAR_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// ON_GLOBALVAR:              End completions
-
-struct _S {
-  @#^ON_INIT^# init()
-// ON_INIT:              Begin completions
-// ON_INIT_ENABLED-DAG:  Keyword/None:              abi[#Constructor Attribute#]; name=abi
-// ON_INIT_ENABLED-DAG:  Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// ON_INIT_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// ON_INIT_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// ON_INIT:              End completions
-
-  @#^ON_PROPERTY^# var foo
-// ON_PROPERTY:              Begin completions
-// ON_PROPERTY_ENABLED-DAG:  Keyword/None:              abi[#Var Attribute#]; name=abi
-// ON_PROPERTY_ENABLED-DAG:  Keyword/None:              execution[#Var Attribute#]; name=execution
-// ON_PROPERTY_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// ON_PROPERTY_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// ON_PROPERTY:              End completions
-
-  @#^ON_SUBSCR^# subscript
-// ON_SUBSCR:              Begin completions
-// ON_SUBSCR_ENABLED-DAG:  Keyword/None:              abi[#Declaration Attribute#]; name=abi
-// ON_SUBSCR_ENABLED-DAG:  Keyword/None:              execution[#Declaration Attribute#]; name=execution
-// ON_SUBSCR_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// ON_SUBSCR_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// ON_SUBSCR:              End completions
-
-  @#^ON_METHOD^# private
-  func foo()
-// ON_METHOD:              Begin completions
-// ON_METHOD_ENABLED-DAG:  Keyword/None:              abi[#Func Attribute#]; name=abi
-// ON_METHOD_ENABLED-DAG:  Keyword/None:              execution[#Func Attribute#]; name=execution
-// ON_METHOD_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// ON_METHOD_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// ON_METHOD:              End completions
-
-
-  func bar(@#^ON_PARAM_1?check=ON_PARAM^#)
-// ON_PARAM:              Begin completions
-// ON_PARAM_ENABLED-NOT:  Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// ON_PARAM_ENABLED-NOT:  Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// ON_PARAM_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// ON_PARAM_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// ON_PARAM:              End completions
-
-  func bar(
-    @#^ON_PARAM_2?check=ON_PARAM^#
-
-    arg: Int
-  )
-// Same as ON_PARAM.
-
-  @#^ON_MEMBER_INDEPENDENT_1?check=ON_MEMBER_LAST^#
-
-  func dummy1() {}
-// Same as ON_MEMBER_LAST.
-
-  @#^ON_MEMBER_INDEPENDENT_2?check=ON_MEMBER_LAST^#
-  func dummy2() {}
-// Same as ON_MEMBER_LAST.
-
-
-  @#^ON_MEMBER_LAST^#
-// ON_MEMBER_LAST:              Begin completions
-// ON_MEMBER_LAST_ENABLED-DAG:  Keyword/None:              abi[#Declaration Attribute#]; name=abi
-// ON_MEMBER_LAST_ENABLED-DAG:  Keyword/None:              execution[#Declaration Attribute#]; name=execution
-// ON_MEMBER_LAST_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// ON_MEMBER_LAST_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// ON_MEMBER_LAST:              End completions
-}
-
-func takeClosure(_: () -> Void) {
-  takeClosure { @#^IN_CLOSURE^# in
-    print("x")
-  }
-}
-// IN_CLOSURE:              Begin completions
-// FIXME: Not valid in this position (but CompletionLookup can't tell that)
-// IN_CLOSURE_ENABLED-DAG:  Keyword/None:              abi[#Declaration Attribute#]; name=abi
-// IN_CLOSURE_ENABLED-DAG:  Keyword/None:              execution[#Declaration Attribute#]; name=execution
-// IN_CLOSURE_DISABLED-NOT: Keyword/None:              abi[#{{.*}} Attribute#]; name=abi
-// IN_CLOSURE_DISABLED-NOT: Keyword/None:              execution[#{{.*}} Attribute#]; name=execution
-// IN_CLOSURE:              End completions
-
-@#^KEYWORD_INDEPENDENT_1?check=KEYWORD_LAST^#
-
-func dummy1() {}
-// Same as KEYWORD_LAST.
-
-@#^KEYWORD_INDEPENDENT_2?check=KEYWORD_LAST^#
-func dummy2() {}
-// Same as KEYWORD_LAST.
-
-@#^KEYWORD_LAST^#
-
-// KEYWORD_LAST:              Begin completions
-// KEYWORD_LAST_ENABLED-DAG:  Keyword/None:              abi[#Declaration Attribute#]; name=abi
-// KEYWORD_LAST_ENABLED-DAG:  Keyword/None:              execution[#Declaration Attribute#]; name=execution
-// KEYWORD_LAST_DISABLED-NOT: Keyword/None:              abi[#Declaration Attribute#]; name=abi
-// KEYWORD_LAST_DISABLED-NOT: Keyword/None:              execution[#Declaration Attribute#]; name=execution
-// KEYWORD_LAST:              End completions
diff --git a/test/IDE/complete_doc_member.swift b/test/IDE/complete_doc_member.swift
new file mode 100644
index 0000000000000..1269f88391c5c
--- /dev/null
+++ b/test/IDE/complete_doc_member.swift
@@ -0,0 +1,195 @@
+// RUN: %batch-code-completion -source-filename %s -module-name CompleteDocTest -code-completion-comments -code-completion-sort-by-name
+
+protocol P1 {
+  /// requirement1 doc comment
+  ///
+  /// more description
+  var requirement1: String { get }
+
+  func requirement2()
+  
+  /// requirement3 comment in P1
+  func requirement3(x: Int)
+}
+
+/// struct S
+///
+/// More info on struct S
+struct S1: P1 {
+  /// instanceVar1 description
+  var instanceVar1: String = "OK"
+  
+  /// instanceVar2 description
+  ///
+  /// Euler-Mascheroni constant
+  var instanceVar2: Double = 0.5772156649
+  
+  /// struct instance func comment
+  ///
+  /// Does stuff with the instance.
+  func instanceFunc1() {}
+  
+  /// struct instance func comment
+  ///
+  /// Does stuff with the instance.
+  ///
+  /// - Parameters:
+  ///   - x: what is x?
+  func instanceFunc2(x: String) {}
+  
+  /// subscript on struct S
+  ///
+  /// - Parameters:
+  ///   - index: an index into S1
+  subscript(index: Int) {}
+  
+  var requirement1: String = "name"
+  
+  func requirement2() {}
+  
+  /// requirement3 comment in S1
+  func requirement3() {}
+}
+
+extension S1 {
+  /// doc for extendedFunc1
+  func extendedFunc1(x: Int, y: Int) -> Int {
+    return x + y * 2
+  }
+  
+  func extendedFunc2() {}
+}
+
+func testWithDot() {
+  S1().#^MEMBER_DOT^#
+}
+
+// MEMBER_DOT:      Begin completions, 11 items
+
+// MEMBER_DOT-NEXT:      Decl[InstanceMethod]/CurrNominal:   extendedFunc1({#x: Int#}, {#y: Int#})[#Int#]; name=extendedFunc1(x:y:);
+// MEMBER_DOT-SAME: briefcomment=doc for extendedFunc1;
+// MEMBER_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="56" column="8"><Name>extendedFunc1(x:y:)</Name><USR>s:15CompleteDocTest2S1V13extendedFunc11x1yS2i_SitF</USR><Declaration>func extendedFunc1(x: Int, y: Int) -&gt; Int</Declaration><CommentParts><Abstract><Para>doc for extendedFunc1</Para></Abstract></CommentParts></Function>;
+// MEMBER_DOT-SAME: rawcomment=doc for extendedFunc1
+
+// MEMBER_DOT-NEXT:      Decl[InstanceMethod]/CurrNominal:   extendedFunc2()[#Void#]; name=extendedFunc2(){{$}}
+
+// MEMBER_DOT-NEXT:      Decl[InstanceMethod]/CurrNominal:   instanceFunc1()[#Void#]; name=instanceFunc1();
+// MEMBER_DOT-SAME: briefcomment=struct instance func comment;
+// MEMBER_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="30" column="8"><Name>instanceFunc1()</Name><USR>s:15CompleteDocTest2S1V13instanceFunc1yyF</USR><Declaration>func instanceFunc1()</Declaration><CommentParts><Abstract><Para>struct instance func comment</Para></Abstract><Discussion><Para>Does stuff with the instance.</Para></Discussion></CommentParts></Function>;
+// MEMBER_DOT-SAME: rawcomment=struct instance func comment
+// MEMBER_DOT-EMPTY:
+// MEMBER_DOT-NEXT: Does stuff with the instance.
+
+// MEMBER_DOT-NEXT:      Decl[InstanceMethod]/CurrNominal:   instanceFunc2({#x: String#})[#Void#]; name=instanceFunc2(x:);
+// MEMBER_DOT-SAME: briefcomment=struct instance func comment;
+// MEMBER_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="38" column="8"><Name>instanceFunc2(x:)</Name><USR>s:15CompleteDocTest2S1V13instanceFunc21xySS_tF</USR><Declaration>func instanceFunc2(x: String)</Declaration><CommentParts><Abstract><Para>struct instance func comment</Para></Abstract><Parameters><Parameter><Name>x</Name><Direction isExplicit="0">in</Direction><Discussion><Para>what is x?</Para></Discussion></Parameter></Parameters><Discussion><Para>Does stuff with the instance.</Para></Discussion></CommentParts></Function>;
+// MEMBER_DOT-SAME: rawcomment=struct instance func comment
+// MEMBER_DOT-EMPTY:
+// MEMBER_DOT-NEXT: Does stuff with the instance.
+// MEMBER_DOT-EMPTY:
+// MEMBER_DOT-NEXT: - Parameters:
+// MEMBER_DOT-NEXT:   - x: what is x?
+
+// MEMBER_DOT-NEXT:      Decl[InstanceVar]/CurrNominal:      instanceVar1[#String#]; name=instanceVar1;
+// MEMBER_DOT-SAME: briefcomment=instanceVar1 description;
+// MEMBER_DOT-SAME: xmlcomment=<Other file="{{.*}}" line="20" column="7"><Name>instanceVar1</Name><USR>s:15CompleteDocTest2S1V12instanceVar1SSvp</USR><Declaration>var instanceVar1: String</Declaration><CommentParts><Abstract><Para>instanceVar1 description</Para></Abstract></CommentParts></Other>;
+// MEMBER_DOT-SAME: rawcomment=instanceVar1 description
+
+// MEMBER_DOT-NEXT:      Decl[InstanceVar]/CurrNominal:      instanceVar2[#Double#]; name=instanceVar2;
+// MEMBER_DOT-SAME: briefcomment=instanceVar2 description;
+// MEMBER_DOT-SAME: xmlcomment=<Other file="{{.*}}" line="25" column="7"><Name>instanceVar2</Name><USR>s:15CompleteDocTest2S1V12instanceVar2Sdvp</USR><Declaration>var instanceVar2: Double</Declaration><CommentParts><Abstract><Para>instanceVar2 description</Para></Abstract><Discussion><Para>Euler-Mascheroni constant</Para></Discussion></CommentParts></Other>;
+// MEMBER_DOT-SAME: rawcomment=instanceVar2 description
+// MEMBER_DOT-EMPTY:
+// MEMBER_DOT-NEXT: Euler-Mascheroni constant
+
+// MEMBER_DOT-NEXT:      Decl[InstanceVar]/CurrNominal:      requirement1[#String#]; name=requirement1;
+// MEMBER_DOT-SAME: briefcomment=requirement1 doc comment;
+// MEMBER_DOT-SAME: xmlcomment=<Other file="{{.*}}" line="7" column="7"><Name>requirement1</Name><USR>s:15CompleteDocTest2P1P12requirement1SSvp</USR><Declaration>var requirement1: String { get }</Declaration><CommentParts><Abstract><Para>requirement1 doc comment</Para></Abstract><Discussion><Para>more description</Para><Note><Para>This documentation comment was inherited from <codeVoice>P1</codeVoice>.</Para></Note></Discussion></CommentParts></Other>;
+// MEMBER_DOT-SAME: rawcomment=requirement1 doc comment
+// MEMBER_DOT-EMPTY:
+// MEMBER_DOT-NEXT: more description
+
+// MEMBER_DOT-NEXT:      Decl[InstanceMethod]/CurrNominal:   requirement2()[#Void#]; name=requirement2(){{$}}
+
+// MEMBER_DOT-NEXT:      Decl[InstanceMethod]/CurrNominal:   requirement3()[#Void#]; name=requirement3();
+// MEMBER_DOT-SAME: briefcomment=requirement3 comment in S1;
+// MEMBER_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="51" column="8"><Name>requirement3()</Name><USR>s:15CompleteDocTest2S1V12requirement3yyF</USR><Declaration>func requirement3()</Declaration><CommentParts><Abstract><Para>requirement3 comment in S1</Para></Abstract></CommentParts></Function>;
+// MEMBER_DOT-SAME: rawcomment=requirement3 comment in S1
+
+// MEMBER_DOT-NEXT:      Decl[InstanceMethod]/Super:         requirement3({#x: Int#})[#Void#]; name=requirement3(x:);
+// MEMBER_DOT-SAME: briefcomment=requirement3 comment in P1;
+// MEMBER_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="12" column="8"><Name>requirement3(x:)</Name><USR>s:15CompleteDocTest2P1P12requirement31xySi_tF</USR><Declaration>func requirement3(x: Int)</Declaration><CommentParts><Abstract><Para>requirement3 comment in P1</Para></Abstract></CommentParts></Function>;
+// MEMBER_DOT-SAME: rawcomment=requirement3 comment in P1
+
+// MEMBER_DOT-NEXT: Keyword[self]/CurrNominal:          self[#S1#]; name=self{{$}}
+
+func testWithNoDot() {
+  S1()#^MEMBER_NO_DOT^#
+}
+
+// MEMBER_NO_DOT:      Begin completions, 12 items
+
+// MEMBER_NO_DOT-NEXT: Decl[Subscript]/CurrNominal:        [{#(index): Int#}][#_#]; name=[:];
+// MEMBER_NO_DOT-SAME: briefcomment=subscript on struct S;
+// MEMBER_NO_DOT-SAME: xmlcomment=<Other file="{{.*}}" line="44" column="3"><Name>subscript(_:)</Name><USR>s:15CompleteDocTest2S1VyXeXecip</USR><Declaration>subscript(index: Int) -&gt; &lt;&lt;error type&gt;&gt; { get }</Declaration><CommentParts><Abstract><Para>subscript on struct S</Para></Abstract><Parameters><Parameter><Name>index</Name><Direction isExplicit="0">in</Direction><Discussion><Para>an index into S1</Para></Discussion></Parameter></Parameters></CommentParts></Other>;
+// MEMBER_NO_DOT-SAME: rawcomment=subscript on struct S
+// MEMBER_NO_DOT-EMPTY:
+// MEMBER_NO_DOT-NEXT: - Parameters:
+// MEMBER_NO_DOT-NEXT:   - index: an index into S1
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceMethod]/CurrNominal:   .extendedFunc1({#x: Int#}, {#y: Int#})[#Int#]; name=extendedFunc1(x:y:);
+// MEMBER_NO_DOT-SAME: briefcomment=doc for extendedFunc1;
+// MEMBER_NO_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="56" column="8"><Name>extendedFunc1(x:y:)</Name><USR>s:15CompleteDocTest2S1V13extendedFunc11x1yS2i_SitF</USR><Declaration>func extendedFunc1(x: Int, y: Int) -&gt; Int</Declaration><CommentParts><Abstract><Para>doc for extendedFunc1</Para></Abstract></CommentParts></Function>;
+// MEMBER_NO_DOT-SAME: rawcomment=doc for extendedFunc1
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceMethod]/CurrNominal:   .extendedFunc2()[#Void#]; name=extendedFunc2()
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceMethod]/CurrNominal:   .instanceFunc1()[#Void#]; name=instanceFunc1();
+// MEMBER_NO_DOT-SAME: briefcomment=struct instance func comment;
+// MEMBER_NO_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="30" column="8"><Name>instanceFunc1()</Name><USR>s:15CompleteDocTest2S1V13instanceFunc1yyF</USR><Declaration>func instanceFunc1()</Declaration><CommentParts><Abstract><Para>struct instance func comment</Para></Abstract><Discussion><Para>Does stuff with the instance.</Para></Discussion></CommentParts></Function>;
+// MEMBER_NO_DOT-SAME: rawcomment=struct instance func comment
+// MEMBER_NO_DOT-EMPTY:
+// MEMBER_NO_DOT-NEXT: Does stuff with the instance.
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceMethod]/CurrNominal:   .instanceFunc2({#x: String#})[#Void#]; name=instanceFunc2(x:);
+// MEMBER_NO_DOT-SAME: briefcomment=struct instance func comment;
+// MEMBER_NO_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="38" column="8"><Name>instanceFunc2(x:)</Name><USR>s:15CompleteDocTest2S1V13instanceFunc21xySS_tF</USR><Declaration>func instanceFunc2(x: String)</Declaration><CommentParts><Abstract><Para>struct instance func comment</Para></Abstract><Parameters><Parameter><Name>x</Name><Direction isExplicit="0">in</Direction><Discussion><Para>what is x?</Para></Discussion></Parameter></Parameters><Discussion><Para>Does stuff with the instance.</Para></Discussion></CommentParts></Function>;
+// MEMBER_NO_DOT-SAME: rawcomment=struct instance func comment
+// MEMBER_NO_DOT-EMPTY:
+// MEMBER_NO_DOT-NEXT: Does stuff with the instance.
+// MEMBER_NO_DOT-EMPTY:
+// MEMBER_NO_DOT-NEXT: - Parameters:
+// MEMBER_NO_DOT-NEXT:   - x: what is x?
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceVar]/CurrNominal:      .instanceVar1[#String#]; name=instanceVar1;
+// MEMBER_NO_DOT-SAME: briefcomment=instanceVar1 description;
+// MEMBER_NO_DOT-SAME: xmlcomment=<Other file="{{.*}}" line="20" column="7"><Name>instanceVar1</Name><USR>s:15CompleteDocTest2S1V12instanceVar1SSvp</USR><Declaration>var instanceVar1: String</Declaration><CommentParts><Abstract><Para>instanceVar1 description</Para></Abstract></CommentParts></Other>;
+// MEMBER_NO_DOT-SAME: rawcomment=instanceVar1 description
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceVar]/CurrNominal:      .instanceVar2[#Double#]; name=instanceVar2;
+// MEMBER_NO_DOT-SAME: briefcomment=instanceVar2 description;
+// MEMBER_NO_DOT-SAME: xmlcomment=<Other file="{{.*}}" line="25" column="7"><Name>instanceVar2</Name><USR>s:15CompleteDocTest2S1V12instanceVar2Sdvp</USR><Declaration>var instanceVar2: Double</Declaration><CommentParts><Abstract><Para>instanceVar2 description</Para></Abstract><Discussion><Para>Euler-Mascheroni constant</Para></Discussion></CommentParts></Other>;
+// MEMBER_NO_DOT-SAME: rawcomment=instanceVar2 description
+// MEMBER_NO_DOT-EMPTY:
+// MEMBER_NO_DOT-NEXT: Euler-Mascheroni constant
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceVar]/CurrNominal:      .requirement1[#String#]; name=requirement1;
+// MEMBER_NO_DOT-SAME: briefcomment=requirement1 doc comment;
+// MEMBER_NO_DOT-SAME: xmlcomment=<Other file="{{.*}}" line="7" column="7"><Name>requirement1</Name><USR>s:15CompleteDocTest2P1P12requirement1SSvp</USR><Declaration>var requirement1: String { get }</Declaration><CommentParts><Abstract><Para>requirement1 doc comment</Para></Abstract><Discussion><Para>more description</Para><Note><Para>This documentation comment was inherited from <codeVoice>P1</codeVoice>.</Para></Note></Discussion></CommentParts></Other>;
+// MEMBER_NO_DOT-SAME: rawcomment=requirement1 doc comment
+// MEMBER_NO_DOT-EMPTY:
+// MEMBER_NO_DOT-NEXT: more description
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceMethod]/CurrNominal:   .requirement2()[#Void#]; name=requirement2()
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceMethod]/CurrNominal:   .requirement3()[#Void#]; name=requirement3();
+// MEMBER_NO_DOT-SAME: briefcomment=requirement3 comment in S1;
+// MEMBER_NO_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="51" column="8"><Name>requirement3()</Name><USR>s:15CompleteDocTest2S1V12requirement3yyF</USR><Declaration>func requirement3()</Declaration><CommentParts><Abstract><Para>requirement3 comment in S1</Para></Abstract></CommentParts></Function>;
+// MEMBER_NO_DOT-SAME: rawcomment=requirement3 comment in S1
+
+// MEMBER_NO_DOT-NEXT: Decl[InstanceMethod]/Super:         .requirement3({#x: Int#})[#Void#]; name=requirement3(x:);
+// MEMBER_NO_DOT-SAME: briefcomment=requirement3 comment in P1;
+// MEMBER_NO_DOT-SAME: xmlcomment=<Function file="{{.*}}" line="12" column="8"><Name>requirement3(x:)</Name><USR>s:15CompleteDocTest2P1P12requirement31xySi_tF</USR><Declaration>func requirement3(x: Int)</Declaration><CommentParts><Abstract><Para>requirement3 comment in P1</Para></Abstract></CommentParts></Function>;
+// MEMBER_NO_DOT-SAME: rawcomment=requirement3 comment in P1
+
+// MEMBER_NO_DOT-NEXT: Keyword[self]/CurrNominal:          .self[#S1#]; name=self
diff --git a/test/IDE/complete_doc_top_level.swift b/test/IDE/complete_doc_top_level.swift
new file mode 100644
index 0000000000000..ef2abd986104f
--- /dev/null
+++ b/test/IDE/complete_doc_top_level.swift
@@ -0,0 +1,83 @@
+/// top-level var 1 comment
+var topLevelVar1 = "Swift"
+
+/// top-level var 2 comment
+///
+/// the meaning of life
+var topLevelVar2 = 42
+
+/// top-level func 1 comment
+///
+/// Does stuff.
+func topLevelFunc1() {}
+
+/// top-level func 2 comment
+func topLevelFunc2() {}
+
+/// struct S1
+///
+/// More info on struct S
+struct S1 {}
+
+/// C1 description
+///
+/// does some work
+class C1 {}
+
+/// P1 description
+///
+/// defines some functionality
+protocol P1 {}
+
+struct S2: P1 {}
+
+#^TOP_LEVEL^#
+
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -module-name CompleteDocTest -code-completion-comments -code-completion-sort-by-name -code-completion-token=TOP_LEVEL | %FileCheck %s --check-prefix=TOP-LEVEL
+
+// TOP-LEVEL-LABEL: Decl[Class]/CurrModule:             C1[#C1#]; name=C1;
+// TOP-LEVEL-SAME:  briefcomment=C1 description;
+// TOP-LEVEL-SAME:  xmlcomment=<Class file="{{.*}}" line="25" column="7"><Name>C1</Name><USR>s:15CompleteDocTest2C1C</USR><Declaration>class C1</Declaration><CommentParts><Abstract><Para>C1 description</Para></Abstract><Discussion><Para>does some work</Para></Discussion></CommentParts></Class>;
+// TOP-LEVEL-SAME:  rawcomment=C1 description
+// TOP-LEVEL-EMPTY:
+// TOP-LEVEL-NEXT:  does some work
+
+// TOP-LEVEL-LABEL: Decl[Protocol]/CurrModule/Flair[RareType]: P1[#P1#]; name=P1;
+// TOP-LEVEL-SAME:  briefcomment=P1 description;
+// TOP-LEVEL-SAME:  xmlcomment=<Class file="{{.*}}" line="30" column="10"><Name>P1</Name><USR>s:15CompleteDocTest2P1P</USR><Declaration>protocol P1</Declaration><CommentParts><Abstract><Para>P1 description</Para></Abstract><Discussion><Para>defines some functionality</Para></Discussion></CommentParts></Class>;
+// TOP-LEVEL-SAME:  rawcomment=P1 description
+// TOP-LEVEL-EMPTY:
+// TOP-LEVEL-NEXT:  defines some functionality
+
+// TOP-LEVEL-LABEL: Decl[Struct]/CurrModule:            S1[#S1#]; name=S1;
+// TOP-LEVEL-SAME:  briefcomment=struct S1;
+// TOP-LEVEL-SAME:  xmlcomment=<Class file="{{.*}}" line="20" column="8"><Name>S1</Name><USR>s:15CompleteDocTest2S1V</USR><Declaration>struct S1</Declaration><CommentParts><Abstract><Para>struct S1</Para></Abstract><Discussion><Para>More info on struct S</Para></Discussion></CommentParts></Class>;
+// TOP-LEVEL-SAME:  rawcomment=struct S1
+// TOP-LEVEL-EMPTY:
+// TOP-LEVEL-NEXT:  More info on struct S
+
+// TOP-LEVEL-LABEL: Decl[Struct]/CurrModule:            S2[#S2#]; name=S2{{$}}
+
+// TOP-LEVEL-LABEL: Decl[FreeFunction]/CurrModule:      topLevelFunc1()[#Void#]; name=topLevelFunc1();
+// TOP-LEVEL-SAME:  briefcomment=top-level func 1 comment;
+// TOP-LEVEL-SAME:  xmlcomment=<Function file="{{.*}}" line="12" column="6"><Name>topLevelFunc1()</Name><USR>s:15CompleteDocTest13topLevelFunc1yyF</USR><Declaration>func topLevelFunc1()</Declaration><CommentParts><Abstract><Para>top-level func 1 comment</Para></Abstract><Discussion><Para>Does stuff.</Para></Discussion></CommentParts></Function>;
+// TOP-LEVEL-SAME:  rawcomment=top-level func 1 comment
+// TOP-LEVEL-EMPTY:
+// TOP-LEVEL-NEXT:  Does stuff.
+
+// TOP-LEVEL-LABEL: Decl[FreeFunction]/CurrModule:      topLevelFunc2()[#Void#]; name=topLevelFunc2();
+// TOP-LEVEL-SAME:  briefcomment=top-level func 2 comment;
+// TOP-LEVEL-SAME:  xmlcomment=<Function file="{{.*}}" line="15" column="6"><Name>topLevelFunc2()</Name><USR>s:15CompleteDocTest13topLevelFunc2yyF</USR><Declaration>func topLevelFunc2()</Declaration><CommentParts><Abstract><Para>top-level func 2 comment</Para></Abstract></CommentParts></Function>;
+// TOP-LEVEL-SAME:  rawcomment=top-level func 2 comment
+
+// TOP-LEVEL-LABEL: Decl[GlobalVar]/Local:              topLevelVar1[#String#]; name=topLevelVar1;
+// TOP-LEVEL-SAME:  briefcomment=top-level var 1 comment;
+// TOP-LEVEL-SAME:  xmlcomment=<Other file="{{.*}}" line="2" column="5"><Name>topLevelVar1</Name><USR>s:15CompleteDocTest12topLevelVar1SSvp</USR><Declaration>var topLevelVar1: String</Declaration><CommentParts><Abstract><Para>top-level var 1 comment</Para></Abstract></CommentParts></Other>;
+// TOP-LEVEL-SAME:  rawcomment=top-level var 1 comment
+
+// TOP-LEVEL-LABEL: Decl[GlobalVar]/Local:              topLevelVar2[#Int#]; name=topLevelVar2;
+// TOP-LEVEL-SAME:  briefcomment=top-level var 2 comment;
+// TOP-LEVEL-SAME:  xmlcomment=<Other file="{{.*}}" line="7" column="5"><Name>topLevelVar2</Name><USR>s:15CompleteDocTest12topLevelVar2Sivp</USR><Declaration>var topLevelVar2: Int</Declaration><CommentParts><Abstract><Para>top-level var 2 comment</Para></Abstract><Discussion><Para>the meaning of life</Para></Discussion></CommentParts></Other>;
+// TOP-LEVEL-SAME:  rawcomment=top-level var 2 comment
+// TOP-LEVEL-EMPTY:
+// TOP-LEVEL-NEXT:  the meaning of life
diff --git a/test/IDE/complete_enum_elements.swift b/test/IDE/complete_enum_elements.swift
index a7711055ba305..6beb9d7c56d0d 100644
--- a/test/IDE/complete_enum_elements.swift
+++ b/test/IDE/complete_enum_elements.swift
@@ -153,14 +153,14 @@ enum BazEnum<T> {
 // BAZ_INT_ENUM_NO_DOT-DAG: Keyword[self]/CurrNominal:        .self[#BazEnum<Int>.Type#]; name=self
 // BAZ_INT_ENUM_NO_DOT-DAG: Keyword/CurrNominal:              .Type[#BazEnum<Int>.Type#]; name=Type
 
-// BAZ_T_ENUM_NO_DOT-DAG: Decl[EnumElement]/CurrNominal:    .Baz1[#BazEnum<_>#]{{; name=.+$}}
-// BAZ_T_ENUM_NO_DOT-DAG: Decl[EnumElement]/CurrNominal:    .Baz2({#_#})[#BazEnum<_>#]{{; name=.+$}}
-// BAZ_T_ENUM_NO_DOT-DAG: Decl[InstanceMethod]/CurrNominal: .bazInstanceFunc({#(self): &BazEnum<_>#})[#() -> Void#]{{; name=.+$}}
+// BAZ_T_ENUM_NO_DOT-DAG: Decl[EnumElement]/CurrNominal:    .Baz1[#BazEnum<T>#]{{; name=.+$}}
+// BAZ_T_ENUM_NO_DOT-DAG: Decl[EnumElement]/CurrNominal:    .Baz2({#T#})[#BazEnum<T>#]{{; name=.+$}}
+// BAZ_T_ENUM_NO_DOT-DAG: Decl[InstanceMethod]/CurrNominal: .bazInstanceFunc({#(self): &BazEnum<T>#})[#() -> Void#]{{; name=.+$}}
 // BAZ_T_ENUM_NO_DOT-DAG: Decl[StaticVar]/CurrNominal:      .staticVar[#Int#]{{; name=.+$}}
-// BAZ_T_ENUM_NO_DOT-DAG: Decl[StaticVar]/CurrNominal:      .staticVarT[#_#]{{; name=.+$}}
+// BAZ_T_ENUM_NO_DOT-DAG: Decl[StaticVar]/CurrNominal:      .staticVarT[#T#]{{; name=.+$}}
 // BAZ_T_ENUM_NO_DOT-DAG: Decl[StaticMethod]/CurrNominal/TypeRelation[Invalid]:   .bazStaticFunc()[#Void#]{{; name=.+$}}
-// BAZ_T_ENUM_NO_DOT-DAG: Keyword[self]/CurrNominal:        .self[#BazEnum<_>.Type#]; name=self
-// BAZ_T_ENUM_NO_DOT-DAG: Keyword/CurrNominal:              .Type[#BazEnum<_>.Type#]; name=Type
+// BAZ_T_ENUM_NO_DOT-DAG: Keyword[self]/CurrNominal:        .self[#BazEnum<T>.Type#]; name=self
+// BAZ_T_ENUM_NO_DOT-DAG: Keyword/CurrNominal:              .Type[#BazEnum<T>.Type#]; name=Type
 
 // BAZ_INT_ENUM_DOT: Begin completions, 8 items
 // BAZ_INT_ENUM_DOT-DAG: Keyword[self]/CurrNominal:        self[#BazEnum<Int>.Type#]; name=self
@@ -173,13 +173,13 @@ enum BazEnum<T> {
 // BAZ_INT_ENUM_DOT-DAG: Decl[StaticMethod]/CurrNominal/TypeRelation[Invalid]:   bazStaticFunc()[#Void#]{{; name=.+$}}
 
 // BAZ_T_ENUM_DOT: Begin completions, 8 items
-// BAZ_T_ENUM_DOT-DAG: Keyword[self]/CurrNominal:        self[#BazEnum<_>.Type#]; name=self
-// BAZ_T_ENUM_DOT-DAG: Keyword/CurrNominal:              Type[#BazEnum<_>.Type#]; name=Type
-// BAZ_T_ENUM_DOT-DAG: Decl[EnumElement]/CurrNominal:    Baz1[#BazEnum<_>#]{{; name=.+$}}
-// BAZ_T_ENUM_DOT-DAG: Decl[EnumElement]/CurrNominal:    Baz2({#_#})[#BazEnum<_>#]{{; name=.+$}}
-// BAZ_T_ENUM_DOT-DAG: Decl[InstanceMethod]/CurrNominal: bazInstanceFunc({#(self): &BazEnum<_>#})[#() -> Void#]{{; name=.+$}}
+// BAZ_T_ENUM_DOT-DAG: Keyword[self]/CurrNominal:        self[#BazEnum<T>.Type#]; name=self
+// BAZ_T_ENUM_DOT-DAG: Keyword/CurrNominal:              Type[#BazEnum<T>.Type#]; name=Type
+// BAZ_T_ENUM_DOT-DAG: Decl[EnumElement]/CurrNominal:    Baz1[#BazEnum<T>#]{{; name=.+$}}
+// BAZ_T_ENUM_DOT-DAG: Decl[EnumElement]/CurrNominal:    Baz2({#T#})[#BazEnum<T>#]{{; name=.+$}}
+// BAZ_T_ENUM_DOT-DAG: Decl[InstanceMethod]/CurrNominal: bazInstanceFunc({#(self): &BazEnum<T>#})[#() -> Void#]{{; name=.+$}}
 // BAZ_T_ENUM_DOT-DAG: Decl[StaticVar]/CurrNominal:      staticVar[#Int#]{{; name=.+$}}
-// BAZ_T_ENUM_DOT-DAG: Decl[StaticVar]/CurrNominal:      staticVarT[#_#]{{; name=.+$}}
+// BAZ_T_ENUM_DOT-DAG: Decl[StaticVar]/CurrNominal:      staticVarT[#T#]{{; name=.+$}}
 // BAZ_T_ENUM_DOT-DAG: Decl[StaticMethod]/CurrNominal/TypeRelation[Invalid]:   bazStaticFunc()[#Void#]{{; name=.+$}}
 
 enum QuxEnum : Int {
diff --git a/test/IDE/complete_expr_postfix_begin.swift b/test/IDE/complete_expr_postfix_begin.swift
index d332cd169de9f..cf24d7bfaf249 100644
--- a/test/IDE/complete_expr_postfix_begin.swift
+++ b/test/IDE/complete_expr_postfix_begin.swift
@@ -27,18 +27,18 @@ protocol FooProtocol {
 typealias FooTypealias = Int
 
 // Function parameter
-// COMMON-DAG: Decl[LocalVar]/Local: fooParam[#FooStruct#]{{; name=.+$}}
+// COMMON-DAG: Decl[LocalVar]/Local{{(/TypeRelation\[Convertible\])?}}: fooParam[#FooStruct#]; name=fooParam
 // Global completions
-// COMMON-DAG: Decl[Struct]/CurrModule:     FooStruct[#FooStruct#]{{; name=.+$}}
-// COMMON-DAG: Decl[Enum]/CurrModule:       FooEnum[#FooEnum#]{{; name=.+$}}
-// COMMON-DAG: Decl[Class]/CurrModule:      FooClass[#FooClass#]{{; name=.+$}}
-// COMMON-DAG: Decl[Protocol]/CurrModule/Flair[RareType]: FooProtocol[#FooProtocol#]{{; name=.+$}}
+// COMMON-DAG: Decl[Struct]/CurrModule{{(/TypeRelation\[Convertible\])?}}:     FooStruct[#FooStruct#]{{; name=.+$}}
+// COMMON-DAG: Decl[Enum]/CurrModule{{(/TypeRelation\[Convertible\])?}}:       FooEnum[#FooEnum#]{{; name=.+$}}
+// COMMON-DAG: Decl[Class]/CurrModule{{(/TypeRelation\[Convertible\])?}}:      FooClass[#FooClass#]{{; name=.+$}}
+// COMMON-DAG: Decl[Protocol]/CurrModule/Flair[RareType]{{(/TypeRelation\[Convertible\])?}}: FooProtocol[#FooProtocol#]{{; name=.+$}}
 // COMMON-DAG: Decl[TypeAlias]/CurrModule{{(/TypeRelation\[Convertible\])?}}:  FooTypealias[#Int#]{{; name=.+$}}
-// COMMON-DAG: Decl[GlobalVar]/CurrModule:  fooObject[#FooStruct#]{{; name=.+$}}
+// COMMON-DAG: Decl[GlobalVar]/CurrModule{{(/TypeRelation\[Convertible\])?}}:  fooObject[#FooStruct#]{{; name=.+$}}
 // COMMON-DAG: Keyword[try]/None: try{{; name=.+$}}
 // COMMON-DAG: Literal[Boolean]/None{{(/TypeRelation\[Convertible\])?}}: true[#Bool#]{{; name=.+$}}
 // COMMON-DAG: Literal[Boolean]/None{{(/TypeRelation\[Convertible\])?}}: false[#Bool#]{{; name=.+$}}
-// COMMON-DAG: Literal[Nil]/None: nil{{; name=.+$}}
+// COMMON-DAG: Literal[Nil]/None{{(/TypeRelation\[Convertible\])?}}: nil{{.*; name=.+$}}
 // COMMON-DAG: Decl[Struct]/OtherModule[Swift]/IsSystem{{(/TypeRelation\[Convertible\])?}}:    Int8[#Int8#]{{; name=.+$}}
 // COMMON-DAG: Decl[Struct]/OtherModule[Swift]/IsSystem{{(/TypeRelation\[Convertible\])?}}:    Int16[#Int16#]{{; name=.+$}}
 // COMMON-DAG: Decl[Struct]/OtherModule[Swift]/IsSystem{{(/TypeRelation\[Convertible\])?}}:    Int32[#Int32#]{{; name=.+$}}
diff --git a/test/IDE/complete_flair_cache.swift b/test/IDE/complete_flair_cache.swift
index 335c97a8e8690..2124c2e0e8124 100644
--- a/test/IDE/complete_flair_cache.swift
+++ b/test/IDE/complete_flair_cache.swift
@@ -8,7 +8,7 @@
 struct MyStruct {}
 protocol MyProtocol {}
 
-func testType() {
+func testType1() {
     let a: #^TYPE^#
 // TYPE-NOT: Keyword[import]
 // TYPE-NOT: Keyword[struct]
@@ -19,7 +19,7 @@ func testType() {
 // TYPE-DAG: Decl[Struct]/OtherModule[Swift]/IsSystem: Int[#Int#]; name=Int
 }
 
-func testType() {
+func testType2() {
     #^EXPR^#
 // EXPR-DAG: Keyword[import]/None/Flair[RareKeyword]: import; name=import
 // EXPR-DAG: Keyword[struct]/None/Flair[RareKeyword]: struct; name=struct
diff --git a/test/IDE/complete_from_clang_framework_typechecker.swift b/test/IDE/complete_from_clang_framework_typechecker.swift
index 4bce3edbd66ed..117d0f05a686b 100644
--- a/test/IDE/complete_from_clang_framework_typechecker.swift
+++ b/test/IDE/complete_from_clang_framework_typechecker.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-objc-interop -F %S/Inputs/mock-sdk
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-objc-interop -F %S/Inputs/mock-sdk
 
 import Foo
 // Don't import 'FooHelper'.
diff --git a/test/IDE/complete_from_swift_module.swift b/test/IDE/complete_from_swift_module.swift
index 0c9d86feca678..7be6ca09904d3 100644
--- a/test/IDE/complete_from_swift_module.swift
+++ b/test/IDE/complete_from_swift_module.swift
@@ -98,16 +98,16 @@ func testCompleteModuleQualified2() {
 func testCompleteModuleQualified3() {
   foo_swift_module.BarGenericSwiftStruct1#^MODULE_QUALIFIED_3^#
 }
-// MODULE_QUALIFIED_3-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]: ({#t: _#})[#BarGenericSwiftStruct1<_>#]; name=(t:)
-// MODULE_QUALIFIED_3-DAG: Decl[InstanceMethod]/CurrNominal: .bar1InstanceFunc({#(self): BarGenericSwiftStruct1<_>#})[#() -> Void#]; name=bar1InstanceFunc(:)
+// MODULE_QUALIFIED_3-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]: ({#t: T#})[#BarGenericSwiftStruct1<T>#]; name=(t:)
+// MODULE_QUALIFIED_3-DAG: Decl[InstanceMethod]/CurrNominal: .bar1InstanceFunc({#(self): BarGenericSwiftStruct1<T>#})[#() -> Void#]; name=bar1InstanceFunc(:)
 
 func testCompleteModuleQualified4() {
   foo_swift_module.BarGenericSwiftStruct2#^MODULE_QUALIFIED_4^#
 }
-// MODULE_QUALIFIED_4-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]: ({#t: _#}, {#u: _#})[#BarGenericSwiftStruct2<_, _>#]; name=(t:u:)
-// MODULE_QUALIFIED_4-DAG: Decl[InstanceMethod]/CurrNominal: .bar2InstanceFunc({#(self): BarGenericSwiftStruct2<_, _>#})[#() -> Void#]; name=bar2InstanceFunc(:)
-// MODULE_QUALIFIED_4-DAG: Keyword[self]/CurrNominal: .self[#BarGenericSwiftStruct2<_, _>.Type#]; name=self
-// MODULE_QUALIFIED_4-DAG: Keyword/CurrNominal: .Type[#BarGenericSwiftStruct2<_, _>.Type#]; name=Type
+// MODULE_QUALIFIED_4-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]: ({#t: T#}, {#u: U#})[#BarGenericSwiftStruct2<T, U>#]; name=(t:u:)
+// MODULE_QUALIFIED_4-DAG: Decl[InstanceMethod]/CurrNominal: .bar2InstanceFunc({#(self): BarGenericSwiftStruct2<T, U>#})[#() -> Void#]; name=bar2InstanceFunc(:)
+// MODULE_QUALIFIED_4-DAG: Keyword[self]/CurrNominal: .self[#BarGenericSwiftStruct2<T, U>.Type#]; name=self
+// MODULE_QUALIFIED_4-DAG: Keyword/CurrNominal: .Type[#BarGenericSwiftStruct2<T, U>.Type#]; name=Type
 
 func testCompleteModuleQualified5() {
   corrupted_module.#^MODULE_QUALIFIED_5^#
diff --git a/test/IDE/complete_if_switch_expr.swift b/test/IDE/complete_if_switch_expr.swift
index 97b6c145a39e2..50e58285638fa 100644
--- a/test/IDE/complete_if_switch_expr.swift
+++ b/test/IDE/complete_if_switch_expr.swift
@@ -225,7 +225,7 @@ func testSkipTypeChecking8() throws -> E {
   return e
 }
 
-func testSkipTypeChecking8() throws -> E {
+func testSkipTypeChecking8a() throws -> E {
   // Only need to type-check the inner function in this case.
   let e: E = if Bool.random() {
     func localFunc() {
diff --git a/test/IDE/complete_in_result_builder.swift b/test/IDE/complete_in_result_builder.swift
index 368b914b636b1..37640845e9b82 100644
--- a/test/IDE/complete_in_result_builder.swift
+++ b/test/IDE/complete_in_result_builder.swift
@@ -16,7 +16,10 @@ struct TupleBuilder<T> {
   }
 }
 
-func buildStringTuple<Result>(@TupleBuilder<String> x: () -> Result) {}
+@discardableResult
+func buildStringTuple<Result>(@TupleBuilder<String> x: () -> Result) -> Result {
+  x()
+}
 
 enum StringFactory {
   static func makeString(x: String) -> String { return x }
@@ -50,6 +53,12 @@ func testGlobalLookup() {
     }
   }
 
+  buildStringTuple {
+    if {
+      #^GLOBAL_LOOKUP_IN_IF_BODY_WITHOUT_CONDITION_CLOSURE?check=GLOBAL_LOOKUP_IN_IF_BODY^#
+    }
+  }
+
   @TupleBuilder<String> var x4 {
     guard else {
       #^GLOBAL_LOOKUP_IN_GUARD_BODY_WITHOUT_CONDITION?check=GLOBAL_LOOKUP_IN_IF_BODY^#
@@ -98,6 +107,21 @@ struct FooStruct {
   func intGen() -> Int { return 1 }
 }
 
+func testReturn() {
+  // Make sure we can still complete even with return.
+  buildStringTuple {
+    StringFactory.#^COMPLETE_STATIC_MEMBER_WITH_RETURN^#
+    // COMPLETE_STATIC_MEMBER_WITH_RETURN: Decl[StaticMethod]/CurrNominal:     makeString({#x: String#})[#String#];
+    return ""
+  }
+
+  buildStringTuple {
+    ""
+    return FooStruct()
+  }.#^COMPLETE_INSTANCE_MEMBER_ON_RETURN_BUILDER^#
+  // COMPLETE_INSTANCE_MEMBER_ON_RETURN_BUILDER: Decl[InstanceVar]/CurrNominal: instanceVar[#Int#]; name=instanceVar
+}
+
 func testPatternMatching() {
   @TupleBuilder<String> var x1 {
     let x = Letters.b
@@ -128,6 +152,11 @@ func testPatternMatching() {
     let x: FooStruct? = FooStruct()
     guard case .#^GUARD_CASE_PATTERN_2?check=OPTIONAL_FOOSTRUCT^#some() = x {}
   }
+
+  buildStringTuple {
+    let x: FooStruct? = FooStruct()
+    guard case .#^GUARD_CASE_PATTERN_3?check=OPTIONAL_FOOSTRUCT^#some() = x {}
+  }
 }
 
 func testCompleteFunctionArgumentLabels() {
@@ -329,13 +358,12 @@ func testSwitchInResultBuilder() {
       Reduce2()
       Reduce2 { action in
         switch action {
-        case .#^SWITCH_IN_RESULT_BUILDER?xfail=rdar106720462^# alertDismissed:
+        case .#^SWITCH_IN_RESULT_BUILDER^# alertDismissed:
           return 0
         }
       }
     }
   }
-// SWITCH_IN_RESULT_BUILDER: Begin completions, 1 item
 // SWITCH_IN_RESULT_BUILDER-DAG: Decl[EnumElement]/CurrNominal/Flair[ExprSpecific]/TypeRelation[Convertible]: alertDismissed[#Action#];
 }
 
@@ -410,3 +438,24 @@ func testInForLoop(_ x: [Int]) {
     }
   }
 }
+
+func testUnsupportedForLoop() {
+  @resultBuilder
+  struct Builder {
+    static func buildBlock<T>(_ components: T...) -> T {
+      components.first!
+    }
+  }
+
+  func foo(@Builder fn: () -> Int) {}
+
+  foo {
+    for i in [0].#^COMPLETE_IN_UNSUPPORTED_FOR^# {}
+  }
+  // COMPLETE_IN_UNSUPPORTED_FOR: Decl[InstanceVar]/Super/IsSystem: first[#Int?#]; name=first
+
+  foo {
+    for i in [0].#^COMPLETE_IN_UNSUPPORTED_FOR_2?check=COMPLETE_IN_UNSUPPORTED_FOR^# {}
+    return 0
+  }
+}
diff --git a/test/IDE/complete_init.swift b/test/IDE/complete_init.swift
index db5469201a63f..a36081020d3d9 100644
--- a/test/IDE/complete_init.swift
+++ b/test/IDE/complete_init.swift
@@ -138,8 +138,8 @@ typealias CAlias = C
 
 var CAliasInstance = CAlias(#^ALIAS_CONSTRUCTOR_0^#
 // rdar://18586415
-// ALIAS_CONSTRUCTOR_0: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#x: A#}[')'][#CAlias#];
-// ALIAS_CONSTRUCTOR_0: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#y: A#}[')'][#CAlias#];
+// ALIAS_CONSTRUCTOR_0: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#x: A#}[')'][#C#];
+// ALIAS_CONSTRUCTOR_0: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ['(']{#y: A#}[')'][#C#];
 
 // https://github.com/apple/swift/issues/57916
 struct Issue57916 {
diff --git a/test/IDE/complete_inline_array.swift b/test/IDE/complete_inline_array.swift
index 26dd743123446..bf63c73b0c4e6 100644
--- a/test/IDE/complete_inline_array.swift
+++ b/test/IDE/complete_inline_array.swift
@@ -1,9 +1,7 @@
-// RUN: %batch-code-completion -enable-experimental-feature InlineArrayTypeSugar
-
-// REQUIRES: swift_feature_InlineArrayTypeSugar
+// RUN: %batch-code-completion
 
 struct FooBar {}
 
-[3 x #^COMPLETE_TOPLEVEL?check=COMPLETE^#
-let _: [3 x #^COMPLETE_TYPE?check=COMPLETE^#
+[3 of #^COMPLETE_TOPLEVEL?check=COMPLETE^#
+let _: [3 of #^COMPLETE_TYPE?check=COMPLETE^#
 // COMPLETE: Decl[Struct]/CurrModule: FooBar[#FooBar#]; name=FooBar
diff --git a/test/IDE/complete_keypath_member_lookup.swift b/test/IDE/complete_keypath_member_lookup.swift
index 156414adbeb77..374aef6211e66 100644
--- a/test/IDE/complete_keypath_member_lookup.swift
+++ b/test/IDE/complete_keypath_member_lookup.swift
@@ -125,13 +125,17 @@ func testGenericUnderconstrained1<G: P>(r: G) {
   r.#^testGenericUnderconstrained1^#
 }
 // testGenericUnderconstrained1-NOT: CurrNominal
-// testGenericUnderconstrained1: Keyword[self]/CurrNominal:          self[#{{any P|G}}#];
+// testGenericUnderconstrained1: Keyword[self]/CurrNominal:          self[#P#];
 // testGenericUnderconstrained1-NOT: CurrNominal
 
 func testExistential1(r: P) {
-  r.#^testExistential1?check=testGenericUnderconstrained1^#
+  r.#^testExistential1^#
 }
 
+// testExistential1-NOT: CurrNominal
+// testExistential1: Keyword[self]/CurrNominal:          self[#any P#];
+// testExistential1-NOT: CurrNominal
+
 @dynamicMemberLookup
 protocol E {
   subscript<U>(dynamicMember member: KeyPath<Point, U>) -> U
diff --git a/test/IDE/complete_keywords.swift b/test/IDE/complete_keywords.swift
index 14979c18e971f..1043045b4d5b8 100644
--- a/test/IDE/complete_keywords.swift
+++ b/test/IDE/complete_keywords.swift
@@ -343,13 +343,13 @@ enum InEnumFunc {
   }
 }
 
-class InClassFunc {
+class InClassFunc1 {
   func testInFuncBody4() {
     #^IN_FUNC_BODY_4?check=KW_DECL_STMT;check=KW_RETURN;check=KW_NO_IN^#
   }
 }
 
-class InClassFunc {
+class InClassFunc2 {
   class Nested {
     func testInFuncBody5() {
       #^IN_FUNC_BODY_5?check=KW_DECL_STMT;check=KW_RETURN;check=KW_NO_IN^#
@@ -377,6 +377,11 @@ struct InInit {
   init?() { #^IN_INIT_1?check=KW_DECL_STMT;check=KW_RETURN;check=KW_NO_IN^# }
 }
 
+struct InGenericTypeInit<T> {
+  init?() { return #^IN_INIT_2?check=KW_FAILABLE_INIT_NIL^# }
+  // KW_FAILABLE_INIT_NIL: Literal[Nil]/None: nil[#InGenericTypeInit<T>?#]; name=nil
+}
+
 struct InStruct {
   #^IN_NOMINAL_DECL_1?check=KW_DECL_TYPECONTEXT;check=KW_NO_INOUT^#
 }
diff --git a/test/IDE/complete_loop.swift b/test/IDE/complete_loop.swift
index 5ec4b45325b49..77a1085a0df4e 100644
--- a/test/IDE/complete_loop.swift
+++ b/test/IDE/complete_loop.swift
@@ -1,72 +1,64 @@
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=LOOP_1 | %FileCheck %s -check-prefix=LOOP_1
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=LOOP_2 > %t.loop2.txt
-// RUN: %FileCheck %s -check-prefix=LOOP_2 < %t.loop2.txt
-// RUN: %FileCheck %s -check-prefix=LOOP_2_NEGATIVE < %t.loop2.txt
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=LOOP_3 | %FileCheck %s -check-prefix=LOOP_3
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=LOOP_4 | %FileCheck %s -check-prefix=LOOP_4
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=LOOP_5 | %FileCheck %s -check-prefix=LOOP_5
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=LOOP_6 | %FileCheck %s -check-prefix=LOOP_6
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=LOOP_7 | %FileCheck %s -check-prefix=LOOP_6
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=LOOP_8 | %FileCheck %s -check-prefix=LOOP_8
+// FIXME: Fails with non-source-ordering
+// RUN: %batch-code-completion -source-order-completion
 
 class Gen {
-	func IntGen() -> Int { return 0 }
-	func IntOpGen() -> Int? {return 0}
-	func IntSeqGen() -> [Int] {return [0]}
+  func IntGen() -> Int { return 0 }
+  func IntOpGen() -> Int? {return 0}
+  func IntSeqGen() -> [Int] {return [0]}
 }
 
 class C {
 
-	func f1(_ Seq : [Int], I : Int, G : Gen) {
-		for i in #^LOOP_1^#
-	}
-// LOOP_1-DAG: Decl[LocalVar]/Local/TypeRelation[Convertible]: Seq[#[Int]#]{{; name=.+$}}
-// LOOP_1-DAG: Decl[LocalVar]/Local:               I[#Int#]{{; name=.+$}}
-// LOOP_1-DAG: Decl[LocalVar]/Local:               G[#Gen#]{{; name=.+$}}
-// LOOP_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: f1({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#]{{; name=.+$}}
-// LOOP_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: f2({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#]{{; name=.+$}}
+  func f1(_ Seq : [Int], I : Int, G : Gen) {
+    for i in #^LOOP_1^#
+  }
+  // LOOP_1-DAG: Decl[LocalVar]/Local/TypeRelation[Convertible]: Seq[#[Int]#]{{; name=.+$}}
+  // LOOP_1-DAG: Decl[LocalVar]/Local:               I[#Int#]{{; name=.+$}}
+  // LOOP_1-DAG: Decl[LocalVar]/Local:               G[#Gen#]{{; name=.+$}}
+  // LOOP_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: f1({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#]{{; name=.+$}}
+  // LOOP_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: f2({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#]{{; name=.+$}}
 
-	func f2(_ Seq : [Int], I : Int, G: Gen) {
-		for i in #^LOOP_2^# {
+  func f2(_ Seq : [Int], I : Int, G: Gen) {
+    for i in #^LOOP_2?check=LOOP_2;check=LOOP_2_NEGATIVE^# {
 
-		}
-	}
-// LOOP_2-DAG: Decl[LocalVar]/Local/TypeRelation[Convertible]: Seq[#[Int]#]{{; name=.+$}}
-// LOOP_2-DAG: Decl[LocalVar]/Local:               I[#Int#]{{; name=.+$}}
-// LOOP_2-DAG: Decl[LocalVar]/Local:               G[#Gen#]{{; name=.+$}}
-// LOOP_2-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: f1({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#]{{; name=.+$}}
-// LOOP_2-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: f2({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#]{{; name=.+$}}
+    }
+  }
+  // LOOP_2-DAG: Decl[LocalVar]/Local/TypeRelation[Convertible]: Seq[#[Int]#]{{; name=.+$}}
+  // LOOP_2-DAG: Decl[LocalVar]/Local:               I[#Int#]{{; name=.+$}}
+  // LOOP_2-DAG: Decl[LocalVar]/Local:               G[#Gen#]{{; name=.+$}}
+  // LOOP_2-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: f1({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#]{{; name=.+$}}
+  // LOOP_2-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: f2({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#]{{; name=.+$}}
 
-// LOOP_2_NEGATIVE-NOT: TypeRelation[{{.*}}]: SequenceType[#SequenceType#];
+  // LOOP_2_NEGATIVE-NOT: TypeRelation[{{.*}}]: SequenceType[#SequenceType#];
 
-	func f3(_ G : Gen) {
-		for i in G.#^LOOP_3^#
-	}
+  func f3(_ G : Gen) {
+    for i in G.#^LOOP_3^#
+  }
 
-// LOOP_3-DAG: Decl[InstanceMethod]/CurrNominal:   IntGen()[#Int#]{{; name=.+$}}
-// LOOP_3-DAG: Decl[InstanceMethod]/CurrNominal:   IntOpGen()[#Int?#]{{; name=.+$}}
-// LOOP_3-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: IntSeqGen()[#[Int]#]{{; name=.+$}}
+  // LOOP_3-DAG: Decl[InstanceMethod]/CurrNominal:   IntGen()[#Int#]{{; name=.+$}}
+  // LOOP_3-DAG: Decl[InstanceMethod]/CurrNominal:   IntOpGen()[#Int?#]{{; name=.+$}}
+  // LOOP_3-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: IntSeqGen()[#[Int]#]{{; name=.+$}}
 
-	func f4(_ G : Gen) {
-		for i in G.#^LOOP_4^# {
+  func f4(_ G : Gen) {
+    for i in G.#^LOOP_4^# {
 
-		}
-	}
+    }
+  }
 
-// LOOP_4-DAG: Decl[InstanceMethod]/CurrNominal:   IntGen()[#Int#]{{; name=.+$}}
-// LOOP_4-DAG: Decl[InstanceMethod]/CurrNominal:   IntOpGen()[#Int?#]{{; name=.+$}}
-// LOOP_4-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: IntSeqGen()[#[Int]#]{{; name=.+$}}
+  // LOOP_4-DAG: Decl[InstanceMethod]/CurrNominal:   IntGen()[#Int#]{{; name=.+$}}
+  // LOOP_4-DAG: Decl[InstanceMethod]/CurrNominal:   IntOpGen()[#Int?#]{{; name=.+$}}
+  // LOOP_4-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: IntSeqGen()[#[Int]#]{{; name=.+$}}
 
   func f5(_ a: [C]) {
     do {
       for user in a {
         user.#^LOOP_5^#
-// LOOP_5-DAG: Keyword[self]/CurrNominal:          self[#C#]; 
-// LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f1({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#];
-// LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f2({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#];
-// LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f3({#(G): Gen#})[#Void#];
-// LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f4({#(G): Gen#})[#Void#];
-// LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f5({#(a): [C]#})[#Void#];
+        // LOOP_5-DAG: Keyword[self]/CurrNominal:          self[#C#];
+        // LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f1({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#];
+        // LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f2({#(Seq): [Int]#}, {#I: Int#}, {#G: Gen#})[#Void#];
+        // LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f3({#(G): Gen#})[#Void#];
+        // LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f4({#(G): Gen#})[#Void#];
+        // LOOP_5-DAG: Decl[InstanceMethod]/CurrNominal:   f5({#(a): [C]#})[#Void#];
       }
     } catch {}
   }
@@ -76,14 +68,29 @@ class C {
 do {
   for value #^LOOP_6^#
 }
+// LOOP_6: Begin completions, 1 items
+// LOOP_6-CHECK-NEXT: Keyword[in]/None:                   in; name=in
+
 do {
   for value #^LOOP_7^# 1..<7 {}
 }
-// LOOP_6: Begin completions, 1 items
-// LOOP_6-CHECK-NEXT: Keyword[in]/None:                   in; name=in
+// LOOP_7: Begin completions
 
 // Pack Iteration
 do {
   for t in #^LOOP_8^# {}
 }
 // LOOP_8-DAG: Keyword[repeat]/None:                   repeat; name=repeat
+
+do {
+  struct S {
+    var foo: Bool
+  }
+  func bar(_ xs: [S]) {
+    // Make sure we can resolve 'x' here without causing a request cycle.
+    for x in xs where x.foo {
+      x.#^LOOP_9^#
+      // LOOP_9-DAG: Decl[InstanceVar]/CurrNominal: foo[#Bool#]; name=foo
+    }
+  }
+}
diff --git a/test/IDE/complete_macros.swift b/test/IDE/complete_macros.swift
index 50993c84425cc..bdcb73325e9af 100644
--- a/test/IDE/complete_macros.swift
+++ b/test/IDE/complete_macros.swift
@@ -21,6 +21,15 @@ public macro freestandingExprStringMacro() -> String
 @freestanding(expression)
 public macro freestandingExprTMacro<T>(_ value: T) -> T
 
+@freestanding(expression)
+public macro freestandingExprVoidClosureMacro(fn: () -> Void)
+
+@freestanding(expression)
+public macro freestandingExprIntClosureMacro(fn: () -> Int)
+
+@freestanding(declaration)
+public macro freestandingDeclVoidClosureMacro(fn: () -> Void)
+
 @freestanding(declaration)
 public macro freestandingDeclMacro()
 
@@ -158,8 +167,21 @@ func nestedFreestanding() {
 // ALL_FREESTANDING-DAG: Decl[Macro]/{{.*}}: freestandingExprTMacro({#(value): T#})[#T#]; name=freestandingExprTMacro(:)
 // ALL_FREESTANDING-DAG: Decl[Macro]/{{.*}}: EverythingMacro[#Expression Macro, Declaration Macro, Accessor Macro, Member Attribute Macro, Member Macro, Peer Macro, Extension Macro#]; name=EverythingMacro
 //
+// We offer a trailing closure completion for the Void case, but not the
+// Int case currently. Placeholder expansion will turn the latter into the
+// former though.
+//
+// ALL_FREESTANDING-DAG: Decl[Macro]/{{.*}}: freestandingExprVoidClosureMacro {|}[#Void#]; name=freestandingExprVoidClosureMacro
+// ALL_FREESTANDING-DAG: Decl[Macro]/{{.*}}: freestandingExprVoidClosureMacro({#fn: () -> Void##() -> Void#})[#Void#]; name=freestandingExprVoidClosureMacro(fn:)
+//
+// ALL_FREESTANDING-DAG: Decl[Macro]/{{.*}}: freestandingExprIntClosureMacro({#fn: () -> Int##() -> Int#})[#Void#]; name=freestandingExprIntClosureMacro(fn:)
+//
+// ALL_FREESTANDING-DAG: Decl[Macro]/{{.*}}: freestandingDeclVoidClosureMacro {|}[#Declaration Macro#]; name=freestandingDeclVoidClosureMacro
+// ALL_FREESTANDING-DAG: Decl[Macro]/{{.*}}: freestandingDeclVoidClosureMacro({#fn: () -> Void##() -> Void#})[#Declaration Macro#]; name=freestandingDeclVoidClosureMacro(fn:)
+//
 // ALL_FREESTANDING_NOT-NOT: Attached
 // ALL_FREESTANDING_NOT-NOT: BodyMacro
+// ALL_FREESTANDING_NOT-NOT: freestandingExprIntClosureMacro {|}
 
 func exprFreestanding(arg: Int) {
   _ = arg + ##^EXPR_FREESTANDING?check=EXPR_FREESTANDING;check=EXPR_FREESTANDING_NOT^#
@@ -181,6 +203,9 @@ struct NestedFreestanding {
 // ITEM_FREESTANDING-DAG: Decl[Macro]/{{.*}}: freestandingDeclMacro[#Declaration Macro#]; name=freestandingDeclMacro
 // ITEM_FREESTANDING-DAG: Decl[Macro]/{{.*}}: EverythingMacro[#Expression Macro, Declaration Macro, Accessor Macro, Member Attribute Macro, Member Macro, Peer Macro, Extension Macro#]; name=EverythingMacro
 //
+// ITEM_FREESTANDING-DAG: Decl[Macro]/{{.*}}: freestandingDeclVoidClosureMacro {|}[#Declaration Macro#]; name=freestandingDeclVoidClosureMacro
+// ITEM_FREESTANDING-DAG: Decl[Macro]/{{.*}}: freestandingDeclVoidClosureMacro({#fn: () -> Void##() -> Void#})[#Declaration Macro#]; name=freestandingDeclVoidClosureMacro(fn:)
+//
 // ITEM_FREESTANDING_NOT-NOT: Attached
 // ITEM_FREESTANDING_NOT-NOT: freestandingExpr
 // ITEM_FREESTANDING_NOT-NOT: freestandingCodeItemMacro
diff --git a/test/IDE/complete_members_optional.swift b/test/IDE/complete_members_optional.swift
index 92933fa86c990..7b84e16991238 100644
--- a/test/IDE/complete_members_optional.swift
+++ b/test/IDE/complete_members_optional.swift
@@ -40,5 +40,5 @@ func optionalMembers2<T : HasOptionalMembers1>(_ a: T) {
 // OPTIONAL_MEMBERS_2-DAG: Decl[InstanceMethod]/CurrNominal: optionalInstanceFunc?({#(self): HasOptionalMembers1#})[#() -> Int#]{{; name=.+$}}
 // OPTIONAL_MEMBERS_2-DAG: Decl[StaticMethod]/CurrNominal: optionalClassFunc?()[#Int#]{{; name=.+$}}
 // OPTIONAL_MEMBERS_2-DAG: Decl[StaticVar]/CurrNominal: optionalClassProperty[#Int?#]{{; name=.+$}}
-// OPTIONAL_MEMBERS_2-DAG: Keyword[self]/CurrNominal: self[#T.Type#]; name=self
-// OPTIONAL_MEMBERS_2-DAG: Keyword/CurrNominal: Type[#T.Type#]; name=Type
+// OPTIONAL_MEMBERS_2-DAG: Keyword[self]/CurrNominal: self[#HasOptionalMembers1.Type#]; name=self
+// OPTIONAL_MEMBERS_2-DAG: Keyword/CurrNominal: Type[#HasOptionalMembers1.Type#]; name=Type
diff --git a/test/IDE/complete_multiple_trailingclosure.swift b/test/IDE/complete_multiple_trailingclosure.swift
index 3f7de84d2b297..555ea76b3a755 100644
--- a/test/IDE/complete_multiple_trailingclosure.swift
+++ b/test/IDE/complete_multiple_trailingclosure.swift
@@ -113,7 +113,7 @@ struct TestStruct2 {
   init(fn1: () -> Int, fn2: () -> String = {}, fn3: () -> String = {}) {}
   func testStructMethod() {}
 }
-func testOptionalInit() {
+func testOptionalInit2() {
   TestStruct2 {
     2
   } #^INIT_OPTIONAL_SAMELINE^#
@@ -148,7 +148,7 @@ struct TestStruct3 {
   init(fn1: () -> Int, fn2: () -> String, fn3: () -> String) {}
   func testStructMethod() {}
 }
-func testOptionalInit() {
+func testOptionalInit1() {
   // missing 'fn2' and 'fn3'.
   TestStruct3 {
     2
diff --git a/test/IDE/complete_name_lookup.swift b/test/IDE/complete_name_lookup.swift
index 0a49716d458eb..1472683fe63d1 100644
--- a/test/IDE/complete_name_lookup.swift
+++ b/test/IDE/complete_name_lookup.swift
@@ -45,8 +45,8 @@ extension ObservableConvertibleType {
         return CatchSequence.#^CATCHSEQUENCE_DOT^#
     }
 }
-// CATCHSEQUENCE_DOT-DAG: Keyword[self]/CurrNominal:          self[#CatchSequence<_>.Type#]; name=self
-// CATCHSEQUENCE_DOT-DAG: Keyword/CurrNominal:                Type[#CatchSequence<_>.Type#]; name=Type
-// CATCHSEQUENCE_DOT-DAG: Decl[Constructor]/CurrNominal/TypeRelation[Convertible]: init()[#CatchSequence<_>#]; name=init()
-// CATCHSEQUENCE_DOT-DAG: Decl[StaticMethod]/Super/TypeRelation[Convertible]: catchError()[#Observable<CatchSequence<_>.T>#]; name=catchError()
-// CATCHSEQUENCE_DOT-DAG: Decl[TypeAlias]/Super: T[#Observable<_.Element.T>.T#]; name=T
+// CATCHSEQUENCE_DOT-DAG: Keyword[self]/CurrNominal:          self[#CatchSequence<S>.Type#]; name=self
+// CATCHSEQUENCE_DOT-DAG: Keyword/CurrNominal:                Type[#CatchSequence<S>.Type#]; name=Type
+// CATCHSEQUENCE_DOT-DAG: Decl[Constructor]/CurrNominal/TypeRelation[Convertible]: init()[#CatchSequence<S>#]; name=init()
+// CATCHSEQUENCE_DOT-DAG: Decl[StaticMethod]/Super/TypeRelation[Convertible]: catchError()[#Observable<CatchSequence<S>.T>#]; name=catchError()
+// CATCHSEQUENCE_DOT-DAG: Decl[TypeAlias]/Super: T[#Observable<S.Element.T>.T#]; name=T
diff --git a/test/IDE/complete_nonexhaustive.swift b/test/IDE/complete_nonexhaustive.swift
new file mode 100644
index 0000000000000..549a333544990
--- /dev/null
+++ b/test/IDE/complete_nonexhaustive.swift
@@ -0,0 +1,7 @@
+// RUN: %batch-code-completion
+
+// NONEXHAUSTIVE-DAG: Keyword/None:                       warn; name=warn
+
+@nonexhaustive(#^NONEXHAUSTIVE^#)
+public enum E {
+}
diff --git a/test/IDE/complete_nonisolated.swift b/test/IDE/complete_nonisolated.swift
new file mode 100644
index 0000000000000..e9ad701b777ba
--- /dev/null
+++ b/test/IDE/complete_nonisolated.swift
@@ -0,0 +1,10 @@
+// RUN: %batch-code-completion
+
+// NONISOLATED-DAG: Keyword/None:                       unsafe; name=unsafe
+// NONISOLATED-DAG: Keyword/None:                       nonsending; name=nonsending
+
+nonisolated(#^NONISOLATED_UNSAFE_TOP_LEVEL?check=NONISOLATED^#) var count = 0
+
+struct MyStruct {
+  nonisolated(#^NONISOLATED_UNSAFE_IN_STRUCT?check=NONISOLATED^#) var prop = 0
+}
diff --git a/test/IDE/complete_nonisolated_unsafe.swift b/test/IDE/complete_nonisolated_unsafe.swift
deleted file mode 100644
index 54edd05f1ac14..0000000000000
--- a/test/IDE/complete_nonisolated_unsafe.swift
+++ /dev/null
@@ -1,9 +0,0 @@
-// RUN: %batch-code-completion
-
-// NONISOLATED_UNSAFE: Keyword/None:                       unsafe; name=unsafe
-
-nonisolated(#^NONISOLATED_UNSAFE_TOP_LEVEL?check=NONISOLATED_UNSAFE^#) var count = 0
-
-struct MyStruct {
-  nonisolated(#^NONISOLATED_UNSAFE_IN_STRUCT?check=NONISOLATED_UNSAFE^#) var prop = 0
-}
diff --git a/test/IDE/complete_operators.swift b/test/IDE/complete_operators.swift
index 2772678e1dbc2..b0d04e2a5317e 100644
--- a/test/IDE/complete_operators.swift
+++ b/test/IDE/complete_operators.swift
@@ -52,7 +52,7 @@ func testPostfix6() {
 func testPostfix7() {
   1 + 2 * 3.0#^POSTFIX_7^#
 }
-// POSTFIX_7: Decl[PostfixOperatorFunction]/CurrModule:  ***[#Double#]
+// POSTFIX_7: Decl[PostfixOperatorFunction]/CurrModule/TypeRelation[Convertible]:  ***[#Double#]
 
 func testPostfix8(x: S) {
   x#^POSTFIX_8^#
@@ -72,7 +72,7 @@ func testPostfix9<G: P where G.T == Int>(x: G) {
 func testPostfix10<G: P where G.T : Fooable>(x: G) {
   x.foo()#^POSTFIX_10^#
 }
-// POSTFIX_10: Decl[PostfixOperatorFunction]/CurrModule: ***[#G.T#]
+// POSTFIX_10: Decl[PostfixOperatorFunction]/CurrModule: ***[#Fooable#]
 
 func testPostfixSpace(x: inout S) {
   x #^S_POSTFIX_SPACE^#
@@ -172,7 +172,7 @@ func ****<T: Fooable>(x: T, y: T) -> T { return x }
 func testInfix9<T: P where T.T: Fooable>(x: T) {
   x.foo()#^INFIX_9?check=FOOABLE_INFIX^#
 }
-// FOOABLE_INFIX: Decl[InfixOperatorFunction]/CurrModule:   **** {#T.T#}[#T.T#]
+// FOOABLE_INFIX: Decl[InfixOperatorFunction]/CurrModule:   **** {#T.T#}[#Fooable#]
 
 func testInfix10<T: P where T.T: Fooable>(x: T) {
   (x.foo() **** x.foo())#^INFIX_10?check=FOOABLE_INFIX^#
@@ -210,8 +210,8 @@ func testInfix15<T: P where T.T == S2>() {
 // INFIX_15: Begin completions, 6 items
 // INFIX_15-DAG: Decl[AssociatedType]/CurrNominal:   .T; name=T
 // INFIX_15-DAG: Decl[InstanceMethod]/CurrNominal:   .foo({#(self): P#})[#() -> S2#]; name=foo(:)
-// INFIX_15-DAG: Keyword[self]/CurrNominal:          .self[#T.Type#]; name=self
-// INFIX_15-DAG: Keyword/CurrNominal:                .Type[#T.Type#]; name=Type
+// INFIX_15-DAG: Keyword[self]/CurrNominal:          .self[#P.Type#]; name=self
+// INFIX_15-DAG: Keyword/CurrNominal:                .Type[#P.Type#]; name=Type
 // INFIX_15-DAG: Decl[InfixOperatorFunction]/OtherModule[Swift]/IsSystem:  != {#(any (~Copyable & ~Escapable).Type)?#}[#Bool#];
 // INFIX_15-DAG: Decl[InfixOperatorFunction]/OtherModule[Swift]/IsSystem:  == {#(any (~Copyable & ~Escapable).Type)?#}[#Bool#];
 
@@ -221,7 +221,7 @@ func testInfix16<T: P where T.T == S2>() {
 
 // INFIX_16: Begin completions, 2 items
 // INFIX_16-DAG: Decl[InstanceMethod]/CurrNominal/Flair[ArgLabels]: ({#(self): P#})[#() -> S2#]; name=(:)
-// INFIX_16-DAG: Keyword[self]/CurrNominal:        .self[#(T) -> () -> S2#]; name=self
+// INFIX_16-DAG: Keyword[self]/CurrNominal:        .self[#(P) -> () -> S2#]; name=self
 
 func testInfix17(x: Void) {
   x#^INFIX_17?check=VOID_OPERATORS^#
diff --git a/test/IDE/complete_pound_keypath.swift b/test/IDE/complete_pound_keypath.swift
index 7480b76fe2278..aabbae91ae67e 100644
--- a/test/IDE/complete_pound_keypath.swift
+++ b/test/IDE/complete_pound_keypath.swift
@@ -49,19 +49,19 @@ func completeInKeyPath2() {
 func completeInKeyPath3() {
    _ = #keyPath(ObjCClass.prop1.#^IN_KEYPATH_3^#
 }
-func completeInKeyPath3() {
+func completeInKeyPath4() {
      _ = #keyPath(String.#^IN_KEYPATH_4^#
 }
 
-func completeInKeyPath4() {
+func completeInKeyPath5() {
   _ = #keyPath(ObjCClass.prop2.#^IN_KEYPATH_5^#
 }
 
-func completeInKeyPath5() {
+func completeInKeyPath6() {
   _ = #keyPath(ObjCClass.prop3.#^IN_KEYPATH_6^#
 }
 
-func completeInKeyPath6() {
+func completeInKeyPath7() {
   _ = #keyPath(ObjCClass.prop4.anythingHere.#^IN_KEYPATH_7^#
 }
 
diff --git a/test/IDE/complete_protocol_static_member.swift b/test/IDE/complete_protocol_static_member.swift
index cba1269b91d18..6c46108fc721c 100644
--- a/test/IDE/complete_protocol_static_member.swift
+++ b/test/IDE/complete_protocol_static_member.swift
@@ -21,7 +21,7 @@ func test<T: FontStyle>(x: T) {
 }
 
 // EXTENSION_NOT_APPLIED: Begin completions, 1 item
-// EXTENSION_NOT_APPLIED-DAG: Keyword[self]/CurrNominal:          self[#T#];
+// EXTENSION_NOT_APPLIED-DAG: Keyword[self]/CurrNominal:          self[#FontStyle#];
 // EXTENSION_NOT_APPLIED-NOT: variableDeclaredInConstraintExtension
 
 struct WrapperStruct<T: FontStyle> {
diff --git a/test/IDE/complete_result_builder.swift b/test/IDE/complete_result_builder.swift
index 96bcde48cd8e1..25029c0cf7acd 100644
--- a/test/IDE/complete_result_builder.swift
+++ b/test/IDE/complete_result_builder.swift
@@ -102,24 +102,24 @@ struct AnyBuilder {
 }
 
 // IN_RESULT_BUILDER_DECL: Begin completions, 10 items
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildBlock(_ components: Any...) -> Any {|}; name=buildBlock(_ components: Any...) -> Any; comment=Required by every
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildExpression(_ expression: <#Expression#>) -> Any {|}; name=buildExpression(_ expression: <#Expression#>) -> Any; comment=
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildOptional(_ component: Any?) -> Any {|}; name=buildOptional(_ component: Any?) -> Any; comment=
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildEither(first component: Any) -> Any {|}; name=buildEither(first component: Any) -> Any; comment=
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildEither(second component: Any) -> Any {|}; name=buildEither(second component: Any) -> Any; comment=
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildArray(_ components: [Any]) -> Any {|}; name=buildArray(_ components: [Any]) -> Any; comment=
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildLimitedAvailability(_ component: Any) -> Any {|}; name=buildLimitedAvailability(_ component: Any) -> Any; comment=
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildFinalResult(_ component: Any) -> <#Result#> {|}; name=buildFinalResult(_ component: Any) -> <#Result#>; comment=
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildPartialBlock(first: Any) -> Any {|}; name=buildPartialBlock(first: Any) -> Any; comment=
-// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildPartialBlock(accumulated: Any, next: Any) -> Any {|}; name=buildPartialBlock(accumulated: Any, next: Any) -> Any; comment=
-
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildBlock(_ components: Any...) -> Any {|}; name=static func buildBlock(_ components: Any...) -> Any; comment=Required by every
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildExpression(_ expression: <#Expression#>) -> Any {|}; name=static func buildExpression(_ expression: <#Expression#>) -> Any; comment=
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildOptional(_ component: Any?) -> Any {|}; name=static func buildOptional(_ component: Any?) -> Any; comment=
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildEither(first component: Any) -> Any {|}; name=static func buildEither(first component: Any) -> Any; comment=
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildEither(second component: Any) -> Any {|}; name=static func buildEither(second component: Any) -> Any; comment=
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildArray(_ components: [Any]) -> Any {|}; name=static func buildArray(_ components: [Any]) -> Any; comment=
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildLimitedAvailability(_ component: Any) -> Any {|}; name=static func buildLimitedAvailability(_ component: Any) -> Any; comment=
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildFinalResult(_ component: Any) -> <#Result#> {|}; name=static func buildFinalResult(_ component: Any) -> <#Result#>; comment=
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildPartialBlock(first: Any) -> Any {|}; name=static func buildPartialBlock(first: Any) -> Any; comment=
-// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildPartialBlock(accumulated: Any, next: Any) -> Any {|}; name=static func buildPartialBlock(accumulated: Any, next: Any) -> Any; comment=
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildBlock(_ components: Any...) -> Any {|}; name=buildBlock(_ components: Any...) -> Any; briefcomment=Required by every
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildExpression(_ expression: <#Expression#>) -> Any {|}; name=buildExpression(_ expression: <#Expression#>) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildOptional(_ component: Any?) -> Any {|}; name=buildOptional(_ component: Any?) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildEither(first component: Any) -> Any {|}; name=buildEither(first component: Any) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildEither(second component: Any) -> Any {|}; name=buildEither(second component: Any) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildArray(_ components: [Any]) -> Any {|}; name=buildArray(_ components: [Any]) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildLimitedAvailability(_ component: Any) -> Any {|}; name=buildLimitedAvailability(_ component: Any) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildFinalResult(_ component: Any) -> <#Result#> {|}; name=buildFinalResult(_ component: Any) -> <#Result#>; briefcomment=
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildPartialBlock(first: Any) -> Any {|}; name=buildPartialBlock(first: Any) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL: Pattern/CurrNominal:                buildPartialBlock(accumulated: Any, next: Any) -> Any {|}; name=buildPartialBlock(accumulated: Any, next: Any) -> Any; briefcomment=
+
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildBlock(_ components: Any...) -> Any {|}; name=static func buildBlock(_ components: Any...) -> Any; briefcomment=Required by every
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildExpression(_ expression: <#Expression#>) -> Any {|}; name=static func buildExpression(_ expression: <#Expression#>) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildOptional(_ component: Any?) -> Any {|}; name=static func buildOptional(_ component: Any?) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildEither(first component: Any) -> Any {|}; name=static func buildEither(first component: Any) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildEither(second component: Any) -> Any {|}; name=static func buildEither(second component: Any) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildArray(_ components: [Any]) -> Any {|}; name=static func buildArray(_ components: [Any]) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildLimitedAvailability(_ component: Any) -> Any {|}; name=static func buildLimitedAvailability(_ component: Any) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildFinalResult(_ component: Any) -> <#Result#> {|}; name=static func buildFinalResult(_ component: Any) -> <#Result#>; briefcomment=
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildPartialBlock(first: Any) -> Any {|}; name=static func buildPartialBlock(first: Any) -> Any; briefcomment=
+// IN_RESULT_BUILDER_DECL_PREFIX: Pattern/CurrNominal: static func buildPartialBlock(accumulated: Any, next: Any) -> Any {|}; name=static func buildPartialBlock(accumulated: Any, next: Any) -> Any; briefcomment=
diff --git a/test/IDE/complete_sequence_invalid.swift b/test/IDE/complete_sequence_invalid.swift
index 908f98a57adf7..40fb8aeb3b018 100644
--- a/test/IDE/complete_sequence_invalid.swift
+++ b/test/IDE/complete_sequence_invalid.swift
@@ -1,10 +1,10 @@
 // RUN: %batch-code-completion
 
-// GLOBAL: Decl[GlobalVar]/CurrModule:         invalidDecl[#<<error type>>#];
+// GLOBAL: Decl[GlobalVar]/CurrModule:         invalidDecl[#_#];
 let invalidDecl = INVALID
 
 struct S {
-  // MEMBER: Decl[InstanceMethod]/CurrNominal:   invalidMethod()[#<<error type>>#];
+  // MEMBER: Decl[InstanceMethod]/CurrNominal:   invalidMethod()[#_#];
   func invalidMethod() -> INVALID
 }
 
diff --git a/test/IDE/complete_shadowing.swift b/test/IDE/complete_shadowing.swift
index 2070b15f98856..2cc67d72e8982 100644
--- a/test/IDE/complete_shadowing.swift
+++ b/test/IDE/complete_shadowing.swift
@@ -180,7 +180,7 @@ func test_Local_GenericParamType() {
   }
 }
 
-func test_Local_GenericParamType() {
+func test_Local_GenericParam() {
   var testValue: String = ""
   func test<testValue>(_: testValue) {
     #^Local_GenericParam?check=GENERICPARAM_TESTVALUE^#
diff --git a/test/IDE/complete_singlevaluestmt_return.swift b/test/IDE/complete_singlevaluestmt_return.swift
new file mode 100644
index 0000000000000..72f93020c5606
--- /dev/null
+++ b/test/IDE/complete_singlevaluestmt_return.swift
@@ -0,0 +1,17 @@
+// RUN: %batch-code-completion
+
+struct S {
+  var str: String
+}
+
+_ = {
+  let k = if .random() {
+    return ""
+  } else {
+    S()
+  }
+  // Make sure we can still infer 'k' here.
+  return k.#^COMPLETE_ON_SVE_WITH_RET^#
+  // COMPLETE_ON_SVE_WITH_RET: Decl[InstanceVar]/CurrNominal/TypeRelation[Convertible]: str[#String#]; name=str
+}
+
diff --git a/test/IDE/complete_sself.swift b/test/IDE/complete_sself.swift
index ff299b6c1f400..7ed9542884468 100644
--- a/test/IDE/complete_sself.swift
+++ b/test/IDE/complete_sself.swift
@@ -4,20 +4,20 @@
 
 // GENERICPARAM: Decl[GenericTypeParam]/Local: Self[#Self#];
 
-// STATICSELF: Keyword[Self]/CurrNominal: Self[#S#];
+// STATICSELF: Keyword[Self]/CurrNominal{{(/TypeRelation\[Convertible\])?}}: Self[#S#];
 
-// DYNAMICSELF: Keyword[Self]/CurrNominal: Self[#Self#];
+// DYNAMICSELF: Keyword[Self]/CurrNominal{{(/TypeRelation\[Convertible\])?}}: Self[#Self#];
 
-func freeFunc() {
+func freeFunc1() {
   #^GLOBAL_BODY_EXPR?check=NOSELF^#
   let _: #^GLOBAL_BODY_TYPE?check=NOSELF^#
 }
 var freeVar: String {
   "\(#^GLOBAL_VARBODY_EXPR?check=NOSELF^#)"
 }
-func freeFunc(x: #^GLOBAL_FUNC_PARAMTYPE?check=NOSELF^#) {}
-func freeFunc(x: Int = #^GLOBAL_FUNC_DEFAULTEXPR?check=NOSELF^#) {}
-func freeFunc(x: Int) -> #^GLOBAL_FUNC_RESULTTYPE?check=NOSELF^# {}
+func freeFunc2(x: #^GLOBAL_FUNC_PARAMTYPE?check=NOSELF^#) {}
+func freeFunc3(x: Int = #^GLOBAL_FUNC_DEFAULTEXPR?check=NOSELF^#) {}
+func freeFunc4(x: Int) -> #^GLOBAL_FUNC_RESULTTYPE?check=NOSELF^# {}
 
 var x: ^#GLOBAL_VAR_TYPE^#
 
@@ -52,38 +52,38 @@ extension P {
 }
 
 struct S {
-  func method(x: #^STRUCT_FUNC_PARAMTYPE?check=STATICSELF^#)
-  func method(x: Int = #^STRUCT_FUNC_DEFAULTEXPR?check=STATICSELF^#) { }
-  func method(x: Int) -> #^STRUCT_FUNC_RESULTTYPE?check=STATICSELF^#
+  func method1(x: #^STRUCT_FUNC_PARAMTYPE?check=STATICSELF^#)
+  func method1(x: Int = #^STRUCT_FUNC_DEFAULTEXPR?check=STATICSELF^#) { }
+  func method1(x: Int) -> #^STRUCT_FUNC_RESULTTYPE?check=STATICSELF^#
 
-  subscript(x: #^STRUCT_SUBSCRIPT_PARAMTYPE?check=STATICSELF^#) -> Int { get }
-  subscript(y: Int) -> #^STRUCT_SUBSCRIPT_RESULTTYPE?check=STATICSELF^# { get }
+  subscript(x1: #^STRUCT_SUBSCRIPT_PARAMTYPE?check=STATICSELF^#) -> Int { get }
+  subscript(y1: Int) -> #^STRUCT_SUBSCRIPT_RESULTTYPE?check=STATICSELF^# { get }
   
-  var x: #^STRUCT_VAR_TYPE?check=STATICSELF^#
+  var x1: #^STRUCT_VAR_TYPE?check=STATICSELF^#
 
-  func bodyTest() {
+  func bodyTest1() {
     #^STRUCT_BODY_EXPR?check=STATICSELF^#
     let _: #^STRUCT_BODY_TYPE?check=STATICSELF^#
   }
-  var varTest: String {
+  var varTest1: String {
     "\(#^STRUCT_VARBODY_EXPR?check=STATICSELF^#)"
   }
 }
 extension S {
-  func method(x: #^STRUCTEXT_FUNC_PARAMTYPE?check=STATICSELF^#)
-  func method(x: Int = #^STRUCTEXT_FUNC_DEFAULTEXPR?check=STATICSELF^#) { }
-  func method(x: Int) -> #^STRUCTEXT_FUNC_RESULTTYPE?check=STATICSELF^#
+  func method2(x: #^STRUCTEXT_FUNC_PARAMTYPE?check=STATICSELF^#)
+  func method2(x: Int = #^STRUCTEXT_FUNC_DEFAULTEXPR?check=STATICSELF^#) { }
+  func method2(x: Int) -> #^STRUCTEXT_FUNC_RESULTTYPE?check=STATICSELF^#
 
-  subscript(x: #^STRUCTEXT_SUBSCRIPT_PARAMTYPE?check=STATICSELF^#) -> Int { get }
-  subscript(y: Int) -> #^STRUCTEXT_SUBSCRIPT_RESULTTYPE?check=STATICSELF^# { get }
+  subscript(x2: #^STRUCTEXT_SUBSCRIPT_PARAMTYPE?check=STATICSELF^#) -> Int { get }
+  subscript(y2: Int) -> #^STRUCTEXT_SUBSCRIPT_RESULTTYPE?check=STATICSELF^# { get }
   
-  var x: #^STRUCTEXT_VAR_TYPE?check=STATICSELF^#
+  var x2: #^STRUCTEXT_VAR_TYPE?check=STATICSELF^#
 
-  func bodyTest() {
+  func bodyTest2() {
     #^STRUCTEXT_BODY_EXPR?check=STATICSELF^#
     let _: #^STRUCTEXT_BODY_TYPE?check=STATICSELF^#
   }
-  var varTest: String {
+  var varTest2: String {
     "\(#^STRUCTEXT_VARBODY_EXPR?check=STATICSELF^#)"
   }
 }
diff --git a/test/IDE/complete_stmt_controlling_expr.swift b/test/IDE/complete_stmt_controlling_expr.swift
index 49570276204e1..6c0f1f26ebf7b 100644
--- a/test/IDE/complete_stmt_controlling_expr.swift
+++ b/test/IDE/complete_stmt_controlling_expr.swift
@@ -413,7 +413,7 @@ func testSwitchCaseWhereExprIJ1(_ fooObject: FooStruct) {
 
 // WITH_I_INT_LOCAL: Decl[LocalVar]/Local: i[#Int#]{{; name=.+$}}
 
-// WITH_I_ERROR_LOCAL: Decl[LocalVar]/Local: i[#<<error type>>#]{{; name=.+$}}
+// WITH_I_ERROR_LOCAL: Decl[LocalVar]/Local: i[#_#]{{; name=.+$}}
 
 // WITH_J_INT: Decl[LocalVar]/Local: j[#Int#]{{; name=.+$}}
 
@@ -486,7 +486,7 @@ func testIfLetBinding2(x: FooStruct?) {
 func testIfLetBinding3(x: FooStruct?) {
   if let y = x, let z = y.#^IF_LET_BIND_3?check=FOOSTRUCT_DOT^# {}
 }
-func testIfLetBinding3(x: FooStruct?) {
+func testIfLetBinding4(x: FooStruct?) {
   if let y = x, let z = y#^IF_LET_BIND_4?check=FOOSTRUCT_NODOT^# {}
 }
 func testGuardLetBinding1(x: FooStruct?) {
@@ -504,7 +504,7 @@ func testGuardLetBinding4(x: FooStruct?) {
 func testGuardLetBinding5(x: FooStruct?) {
   guard let y = x, let z = y.#^GUARD_LET_BIND_5?check=FOOSTRUCT_DOT^# else {}
 }
-func testGuardLetBinding5(x: FooStruct?) {
+func testGuardLetBinding6(x: FooStruct?) {
   guard let y = x, z = y#^GUARD_LET_BIND_6?check=FOOSTRUCT_NODOT^# else {}
 }
 func testGuardLetBinding7(x: FooStruct?) {
@@ -513,10 +513,10 @@ func testGuardLetBinding7(x: FooStruct?) {
 func testGuardLetBinding8(_ x: FooStruct?) {
   guard let boundVal = x, let other = testGuardLetBinding8(#^GUARD_LET_BIND_8?check=FOOSTRUCT_LOCALVAL^#) else {}
 }
-func testGuardCase(x:FooStruct?) {
+func testGuardCase1(x:FooStruct?) {
   guard case .#^GUARD_CASE_PATTERN_1?check=OPTIONAL_FOOSTRUCT^# = x {}
 }
-func testGuardCase(x:FooStruct?) {
+func testGuardCase2(x:FooStruct?) {
   guard case .#^GUARD_CASE_PATTERN_2?check=OPTIONAL_FOOSTRUCT^#some() = x {}
 }
 
diff --git a/test/IDE/complete_subscript.swift b/test/IDE/complete_subscript.swift
index 1c61599fd7531..8f097dff2d5fb 100644
--- a/test/IDE/complete_subscript.swift
+++ b/test/IDE/complete_subscript.swift
@@ -12,10 +12,10 @@ struct MyStruct<T> {
 func test1() {
   let _ = MyStruct #^METATYPE_UNRESOLVED^#
 // METATYPE_UNRESOLVED: Begin completions, 4 items
-// METATYPE_UNRESOLVED-DAG: Decl[Subscript]/CurrNominal:        [{#(x): Int#}, {#static: _#}][#MyStruct<_>#];
-// METATYPE_UNRESOLVED-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ()[#MyStruct<_>#];
-// METATYPE_UNRESOLVED-DAG: Keyword[self]/CurrNominal:          .self[#MyStruct<_>.Type#];
-// METATYPE_UNRESOLVED-DAG: Keyword/CurrNominal:                .Type[#MyStruct<_>.Type#];
+// METATYPE_UNRESOLVED-DAG: Decl[Subscript]/CurrNominal:        [{#(x): Int#}, {#static: T#}][#MyStruct<T>#];
+// METATYPE_UNRESOLVED-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:      ()[#MyStruct<T>#];
+// METATYPE_UNRESOLVED-DAG: Keyword[self]/CurrNominal:          .self[#MyStruct<T>.Type#];
+// METATYPE_UNRESOLVED-DAG: Keyword/CurrNominal:                .Type[#MyStruct<T>.Type#];
 
   let _ = MyStruct[#^METATYPE_UNRESOLVED_BRACKET^#
 // METATYPE_UNRESOLVED_BRACKET-DAG: Decl[Subscript]/CurrNominal/Flair[ArgLabels]:        ['[']{#(x): Int#}, {#static: T#}[']'][#MyStruct<T>#];
@@ -110,7 +110,7 @@ func testSubscriptCallSig<T>(val: MyStruct1<T>) {
   val[#^LABELED_SUBSCRIPT^#
 // LABELED_SUBSCRIPT: Begin completions, 2 items
 // LABELED_SUBSCRIPT-DAG: Decl[Subscript]/CurrNominal/Flair[ArgLabels]:        ['[']{#idx1: Int#}, {#idx2: Comparable#}[']'][#Int!#];
-// LABELED_SUBSCRIPT-DAG: Pattern/CurrNominal/Flair[ArgLabels]:                ['[']{#keyPath: KeyPath<MyStruct1<T>, Value>#}[']'][#Value#];
+// LABELED_SUBSCRIPT-DAG: Pattern/CurrNominal/Flair[ArgLabels]:                ['[']{#keyPath: KeyPath<MyStruct1<Comparable>, Value>#}[']'][#Value#];
 }
 
 func testSubcscriptTuple(val: (x: Int, String)) {
diff --git a/test/IDE/complete_type.swift b/test/IDE/complete_type.swift
index cac06526c5428..4d33aa03e5af4 100644
--- a/test/IDE/complete_type.swift
+++ b/test/IDE/complete_type.swift
@@ -281,7 +281,7 @@ protocol AssocType1 {
 //===--- Test that we can complete types in inheritance clause of associated type declarations.
 //===---
 
-protocol AssocType1 {
+protocol AssocType2 {
   associatedtype AssocType : #^TYPE_IN_ASSOC_TYPE_INHERITANCE_1?check=WITH_GLOBAL_TYPES;check=GLOBAL_NEGATIVE^#
 }
 
@@ -622,7 +622,7 @@ func testTypeIdentifierGeneric1<
 
 // TYPE_IDENTIFIER_GENERIC_1: Begin completions, 2 items
 // TYPE_IDENTIFIER_GENERIC_1-DAG: Decl[AssociatedType]/CurrNominal: FooTypeAlias1{{; name=.+$}}
-// TYPE_IDENTIFIER_GENERIC_1-DAG: Keyword/None:          Type[#GenericFoo.Type#]
+// TYPE_IDENTIFIER_GENERIC_1-DAG: Keyword/None:          Type[#FooProtocol.Type#]
 
 func testTypeIdentifierGeneric2<
     GenericFoo : FooProtocol & BarProtocol
@@ -631,7 +631,7 @@ func testTypeIdentifierGeneric2<
 // TYPE_IDENTIFIER_GENERIC_2: Begin completions, 3 items
 // TYPE_IDENTIFIER_GENERIC_2-DAG: Decl[AssociatedType]/CurrNominal: BarTypeAlias1{{; name=.+$}}
 // TYPE_IDENTIFIER_GENERIC_2-DAG: Decl[AssociatedType]/CurrNominal: FooTypeAlias1{{; name=.+$}}
-// TYPE_IDENTIFIER_GENERIC_2-DAG: Keyword/None:          Type[#GenericFoo.Type#]
+// TYPE_IDENTIFIER_GENERIC_2-DAG: Keyword/None:          Type[#(BarProtocol & FooProtocol).Type#]
 
 func testTypeIdentifierGeneric3<
     GenericFoo>(a: GenericFoo.#^TYPE_IDENTIFIER_GENERIC_3^#
diff --git a/test/IDE/complete_type_subscript.swift b/test/IDE/complete_type_subscript.swift
index b35946d0669ba..b63760d28faf0 100644
--- a/test/IDE/complete_type_subscript.swift
+++ b/test/IDE/complete_type_subscript.swift
@@ -101,7 +101,7 @@ extension G6 {
   subscript(b x: Int) -> T.#^GEN_EXT_RETURN_6^# { return 0 }
 }
 // GEN_PARAM_6-DAG: Decl[AssociatedType]/CurrNominal:   Assoc;
-// GEN_PARAM_6-DAG: Keyword/None:                       Type[#T.Type#];
+// GEN_PARAM_6-DAG: Keyword/None:                       Type[#It.Type#];
 
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=GENPROTO_PARAM_1 | %FileCheck %s -check-prefix=GENPROTO_1
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=GENPROTO_RETURN_1 | %FileCheck %s -check-prefix=GENPROTO_1
@@ -117,4 +117,4 @@ extension GP1 {
   subscript(b x: Int) -> I.#^GENPROTO_EXT_RETURN_1^# { return 1 }
 }
 // GENPROTO_1-DAG: Decl[AssociatedType]/CurrNominal:   Assoc;
-// GENPROTO_1-DAG: Keyword/None:                       Type[#Self.I.Type#];
+// GENPROTO_1-DAG: Keyword/None:                       Type[#It.Type#];
diff --git a/test/IDE/complete_uninferred_generic.swift b/test/IDE/complete_uninferred_generic.swift
index e237821abc2e3..bdb4d04c8904d 100644
--- a/test/IDE/complete_uninferred_generic.swift
+++ b/test/IDE/complete_uninferred_generic.swift
@@ -14,5 +14,5 @@ struct S2<T> : P1 {
 _ = S2()#^UNINFERRED^#
 
 // UNINFERRED-DAG: Decl[Subscript]/Super:     [{#(v0): T#}][#Int#]; name=[:]
-// UNINFERRED-DAG: Decl[Subscript]/Super:     [{#(v0): T#}][#<<error type>>#]; name=[:]
-// UNINFERRED-DAG: Keyword[self]/CurrNominal: .self[#S2<_>#]; name=self
+// UNINFERRED-DAG: Decl[Subscript]/Super:     [{#(v0): T#}][#_#]; name=[:]
+// UNINFERRED-DAG: Keyword[self]/CurrNominal: .self[#S2<T>#]; name=self
diff --git a/test/IDE/complete_unqualified_fallback.swift b/test/IDE/complete_unqualified_fallback.swift
new file mode 100644
index 0000000000000..826652eb38126
--- /dev/null
+++ b/test/IDE/complete_unqualified_fallback.swift
@@ -0,0 +1,56 @@
+// RUN: %batch-code-completion
+
+protocol P0 {}
+protocol P1 {}
+protocol P2 {}
+protocol P3 {}
+protocol P4 {}
+protocol P5 {}
+protocol P6 {}
+protocol P7 {}
+protocol P8 {}
+protocol P9 {}
+
+struct FooBar: P0 {}
+
+@resultBuilder
+struct Builder {
+  static func buildBlock<T>(_ x: T) -> T { x }
+  static func buildExpression<T: P0>(_ x: T) -> T { x }
+  static func buildExpression<T: P1>(_ x: T) -> T { x }
+  static func buildExpression<T: P2>(_ x: T) -> T { x }
+  static func buildExpression<T: P3>(_ x: T) -> T { x }
+  static func buildExpression<T: P4>(_ x: T) -> T { x }
+  static func buildExpression<T: P5>(_ x: T) -> T { x }
+  static func buildExpression<T: P6>(_ x: T) -> T { x }
+  static func buildExpression<T: P7>(_ x: T) -> T { x }
+  static func buildExpression<T: P8>(_ x: T) -> T { x }
+  static func buildExpression<T: P9>(_ x: T) -> T { x }
+}
+
+struct S<T> {}
+extension S: P0 where T : P0 { init(@Builder fn: () -> T) {} }
+extension S: P1 where T : P1 { init(@Builder fn: () -> T) {} }
+extension S: P2 where T : P2 { init(@Builder fn: () -> T) {} }
+extension S: P3 where T : P3 { init(@Builder fn: () -> T) {} }
+extension S: P4 where T : P4 { init(@Builder fn: () -> T) {} }
+extension S: P5 where T : P5 { init(@Builder fn: () -> T) {} }
+extension S: P6 where T : P6 { init(@Builder fn: () -> T) {} }
+extension S: P7 where T : P7 { init(@Builder fn: () -> T) {} }
+extension S: P8 where T : P8 { init(@Builder fn: () -> T) {} }
+extension S: P9 where T : P9 { init(@Builder fn: () -> T) {} }
+
+// This is currently too complex, make sure we can still do an unqualified
+// lookup though.
+S {
+  S {
+    S {
+      S {
+        S {
+          #^COMPLETE^#
+          // COMPLETE: Decl[Struct]/CurrModule: FooBar[#FooBar#]; name=FooBar
+        }
+      }
+    }
+  }
+}
diff --git a/test/IDE/complete_using.swift b/test/IDE/complete_using.swift
new file mode 100644
index 0000000000000..8d6cc2bcf8ef5
--- /dev/null
+++ b/test/IDE/complete_using.swift
@@ -0,0 +1,6 @@
+// RUN: %batch-code-completion
+
+// USING-DAG: Keyword/None:                       @MainActor; name=@MainActor
+// USING-DAG: Keyword/None:                       nonisolated; name=nonisolated
+
+using #^USING^#
diff --git a/test/IDE/complete_value_expr.swift b/test/IDE/complete_value_expr.swift
index 501e7ba306039..43f94e9a33753 100644
--- a/test/IDE/complete_value_expr.swift
+++ b/test/IDE/complete_value_expr.swift
@@ -775,7 +775,7 @@ class TestResolveFuncParam2 {
 
 func testResolveFuncParam3<Foo : FooProtocol>(_ foo: Foo) {
   foo.#^RESOLVE_FUNC_PARAM_3^#
-// RESOLVE_FUNC_PARAM_3-DAG: Keyword[self]/CurrNominal: self[#Foo#]; name=self
+// RESOLVE_FUNC_PARAM_3-DAG: Keyword[self]/CurrNominal: self[#FooProtocol#]; name=self
 // RESOLVE_FUNC_PARAM_3-DAG: Decl[InstanceVar]/CurrNominal: fooInstanceVar1[#Int#]{{; name=.+$}}
 // RESOLVE_FUNC_PARAM_3-DAG: Decl[InstanceVar]/CurrNominal: fooInstanceVar2[#Int#]{{; name=.+$}}
 // RESOLVE_FUNC_PARAM_3-DAG: Decl[InstanceMethod]/CurrNominal: fooInstanceFunc0()[#Double#]{{; name=.+$}}
@@ -784,7 +784,7 @@ func testResolveFuncParam3<Foo : FooProtocol>(_ foo: Foo) {
 
 func testResolveFuncParam4<FooBar : FooProtocol & BarProtocol>(_ fooBar: FooBar) {
   fooBar.#^RESOLVE_FUNC_PARAM_4^#
-// RESOLVE_FUNC_PARAM_4-DAG: Keyword[self]/CurrNominal: self[#FooBar#]; name=self
+// RESOLVE_FUNC_PARAM_4-DAG: Keyword[self]/CurrNominal: self[#BarProtocol & FooProtocol#]; name=self
 // RESOLVE_FUNC_PARAM_4-DAG: Decl[InstanceVar]/CurrNominal:    barInstanceVar[#Int#]{{; name=.+$}}
 // RESOLVE_FUNC_PARAM_4-DAG: Decl[InstanceMethod]/CurrNominal: barInstanceFunc0()[#Double#]{{; name=.+$}}
 // RESOLVE_FUNC_PARAM_4-DAG: Decl[InstanceMethod]/CurrNominal: barInstanceFunc1({#(a): Int#})[#Double#]{{; name=.+$}}
@@ -796,7 +796,7 @@ func testResolveFuncParam4<FooBar : FooProtocol & BarProtocol>(_ fooBar: FooBar)
 
 func testResolveFuncParam5<FooExBarEx : FooExProtocol & BarExProtocol>(_ a: FooExBarEx) {
   a.#^RESOLVE_FUNC_PARAM_5^#
-// RESOLVE_FUNC_PARAM_5-DAG: Keyword[self]/CurrNominal: self[#FooExBarEx#]; name=self
+// RESOLVE_FUNC_PARAM_5-DAG: Keyword[self]/CurrNominal: self[#BarExProtocol & FooExProtocol#]; name=self
 // RESOLVE_FUNC_PARAM_5-DAG: Decl[InstanceMethod]/CurrNominal: barExInstanceFunc0()[#Double#]{{; name=.+$}}
 // RESOLVE_FUNC_PARAM_5-DAG: Decl[InstanceVar]/Super: barInstanceVar[#Int#]{{; name=.+$}}
 // RESOLVE_FUNC_PARAM_5-DAG: Decl[InstanceMethod]/Super: barInstanceFunc0()[#Double#]{{; name=.+$}}
@@ -810,7 +810,7 @@ func testResolveFuncParam5<FooExBarEx : FooExProtocol & BarExProtocol>(_ a: FooE
 
 func testResolveFuncParam6<Foo : FooProtocol where Foo : FooClass>(_ foo: Foo) {
   foo.#^RESOLVE_FUNC_PARAM_6^#
-// RESOLVE_FUNC_PARAM_6-DAG: Keyword[self]/CurrNominal: self[#Foo#]; name=self
+// RESOLVE_FUNC_PARAM_6-DAG: Keyword[self]/CurrNominal: self[#FooClass & FooProtocol#]; name=self
 // RESOLVE_FUNC_PARAM_6-DAG: Decl[InstanceVar]/CurrNominal: fooInstanceVar1[#Int#]{{; name=.+$}}
 // RESOLVE_FUNC_PARAM_6-DAG: Decl[InstanceVar]/CurrNominal: fooInstanceVar2[#Int#]{{; name=.+$}}
 // RESOLVE_FUNC_PARAM_6-DAG: Decl[InstanceMethod]/CurrNominal: fooInstanceFunc0()[#Double#]{{; name=.+$}}
@@ -829,7 +829,7 @@ class TestResolveConstructorParam1 {
 class TestResolveConstructorParam2 {
   init<Foo : FooProtocol>(foo: Foo) {
     foo.#^RESOLVE_CONSTRUCTOR_PARAM_2^#
-// RESOLVE_CONSTRUCTOR_PARAM_2-DAG: Keyword[self]/CurrNominal: self[#Foo#]; name=self
+// RESOLVE_CONSTRUCTOR_PARAM_2-DAG: Keyword[self]/CurrNominal: self[#FooProtocol#]; name=self
 // RESOLVE_CONSTRUCTOR_PARAM_2-DAG: Decl[InstanceVar]/CurrNominal:  fooInstanceVar1[#Int#]{{; name=.+$}}
 // RESOLVE_CONSTRUCTOR_PARAM_2-DAG: Decl[InstanceVar]/CurrNominal:  fooInstanceVar2[#Int#]{{; name=.+$}}
 // RESOLVE_CONSTRUCTOR_PARAM_2-DAG: Decl[InstanceMethod]/CurrNominal: fooInstanceFunc0()[#Double#]{{; name=.+$}}
@@ -840,7 +840,7 @@ class TestResolveConstructorParam2 {
 class TestResolveConstructorParam3<Foo : FooProtocol> {
   init(foo: Foo) {
     foo.#^RESOLVE_CONSTRUCTOR_PARAM_3^#
-// RESOLVE_CONSTRUCTOR_PARAM_3-DAG: Keyword[self]/CurrNominal: self[#Foo#]; name=self
+// RESOLVE_CONSTRUCTOR_PARAM_3-DAG: Keyword[self]/CurrNominal: self[#FooProtocol#]; name=self
 // RESOLVE_CONSTRUCTOR_PARAM_3-DAG: Decl[InstanceVar]/CurrNominal:  fooInstanceVar1[#Int#]{{; name=.+$}}
 // RESOLVE_CONSTRUCTOR_PARAM_3-DAG: Decl[InstanceVar]/CurrNominal:  fooInstanceVar2[#Int#]{{; name=.+$}}
 // RESOLVE_CONSTRUCTOR_PARAM_3-DAG: Decl[InstanceMethod]/CurrNominal: fooInstanceFunc0()[#Double#]{{; name=.+$}}
@@ -913,10 +913,10 @@ func testChainedCalls2() {
 
 func testChainedCalls3() {
   // doBaz() takes a Double.  Check that we can recover.
-  SomeBuilder(42).doFoo().doBaz(SomeBuilder(24))#^CHAINED_CALLS_3?xfail=FIXME^#
+  SomeBuilder(42).doFoo().doBaz(SomeBuilder(24))#^CHAINED_CALLS_3^#
 // CHAINED_CALLS_3-DAG: Decl[InstanceMethod]/CurrNominal: .doFoo()[#SomeBuilder#]{{; name=.+$}}
 // CHAINED_CALLS_3-DAG: Decl[InstanceMethod]/CurrNominal: .doBar()[#SomeBuilder#]{{; name=.+$}}
-// CHAINED_CALLS_3-DAG: Decl[InstanceMethod]/CurrNominal: .doBaz({#z: Double#})[#SomeBuilder#]{{; name=.+$}}
+// CHAINED_CALLS_3-DAG: Decl[InstanceMethod]/CurrNominal: .doBaz({#(z): Double#})[#SomeBuilder#]{{; name=.+$}}
 // CHAINED_CALLS_3-DAG: Keyword[self]/CurrNominal: .self[#SomeBuilder#]; name=self
 }
 
@@ -953,7 +953,7 @@ func testResolveGenericParams2<Foo : FooProtocol>(_ foo: Foo) {
 // RESOLVE_GENERIC_PARAMS_2-DAG: Decl[InstanceMethod]/CurrNominal: .fooVoidInstanceFunc1({#(a): FooProtocol#})[#Void#]{{; name=.+$}}
 // RESOLVE_GENERIC_PARAMS_2-DAG: Decl[InstanceMethod]/CurrNominal: .fooTInstanceFunc1({#(a): FooProtocol#})[#FooProtocol#]{{; name=.+$}}
 // RESOLVE_GENERIC_PARAMS_2-DAG: Decl[InstanceMethod]/CurrNominal: .fooUInstanceFunc1({#(a): U#})[#U#]{{; name=.+$}}
-// RESOLVE_GENERIC_PARAMS_2-DAG: Keyword[self]/CurrNominal:        .self[#FooGenericStruct<Foo>#]; name=self
+// RESOLVE_GENERIC_PARAMS_2-DAG: Keyword[self]/CurrNominal:        .self[#FooGenericStruct<FooProtocol>#]; name=self
 
   FooGenericStruct<Foo>#^RESOLVE_GENERIC_PARAMS_2_STATIC^#
 // RESOLVE_GENERIC_PARAMS_2_STATIC-DAG: Decl[Constructor]/CurrNominal/Flair[ArgLabels]:    ()[#FooGenericStruct<FooProtocol>#]; name=()
@@ -966,8 +966,8 @@ func testResolveGenericParams2<Foo : FooProtocol>(_ foo: Foo) {
 // RESOLVE_GENERIC_PARAMS_2_STATIC-DAG: Decl[StaticMethod]/CurrNominal:   .fooVoidStaticFunc1({#(a): FooProtocol#})[#Void#]{{; name=.+$}}
 // RESOLVE_GENERIC_PARAMS_2_STATIC-DAG: Decl[StaticMethod]/CurrNominal:   .fooTStaticFunc1({#(a): FooProtocol#})[#FooProtocol#]{{; name=.+$}}
 // RESOLVE_GENERIC_PARAMS_2_STATIC-DAG: Decl[StaticMethod]/CurrNominal:   .fooUInstanceFunc1({#(a): U#})[#U#]{{; name=.+$}}
-// RESOLVE_GENERIC_PARAMS_2_STATIC-DAG: Keyword[self]/CurrNominal:        .self[#FooGenericStruct<Foo>.Type#]; name=self
-// RESOLVE_GENERIC_PARAMS_2_STATIC-DAG: Keyword/CurrNominal:              .Type[#FooGenericStruct<Foo>.Type#]; name=Type
+// RESOLVE_GENERIC_PARAMS_2_STATIC-DAG: Keyword[self]/CurrNominal:        .self[#FooGenericStruct<FooProtocol>.Type#]; name=self
+// RESOLVE_GENERIC_PARAMS_2_STATIC-DAG: Keyword/CurrNominal:              .Type[#FooGenericStruct<FooProtocol>.Type#]; name=Type
 
 }
 
@@ -1074,19 +1074,19 @@ class BuilderStyle<T> {
 func testTypeCheckWithUnsolvedVariables1() {
   BuilderStyle().#^TC_UNSOLVED_VARIABLES_1^#
 }
-// TC_UNSOLVED_VARIABLES_1-DAG: Keyword[self]/CurrNominal: self[#BuilderStyle<_>#]; name=self
+// TC_UNSOLVED_VARIABLES_1-DAG: Keyword[self]/CurrNominal: self[#BuilderStyle<T>#]; name=self
 // TC_UNSOLVED_VARIABLES_1-DAG: Decl[InstanceVar]/CurrNominal: count[#Int#]{{; name=.+$}}
-// TC_UNSOLVED_VARIABLES_1-DAG: Decl[InstanceMethod]/CurrNominal: addString({#(s): String#})[#BuilderStyle<_>#]{{; name=.+$}}
-// TC_UNSOLVED_VARIABLES_1-DAG: Decl[InstanceMethod]/CurrNominal: add({#(t): _#})[#BuilderStyle<_>#]{{; name=.+$}}
+// TC_UNSOLVED_VARIABLES_1-DAG: Decl[InstanceMethod]/CurrNominal: addString({#(s): String#})[#BuilderStyle<T>#]{{; name=.+$}}
+// TC_UNSOLVED_VARIABLES_1-DAG: Decl[InstanceMethod]/CurrNominal: add({#(t): T#})[#BuilderStyle<T>#]{{; name=.+$}}
 // TC_UNSOLVED_VARIABLES_1-DAG: Decl[InstanceMethod]/CurrNominal: get()[#Int#]{{; name=.+$}}
 
 func testTypeCheckWithUnsolvedVariables2() {
   BuilderStyle().addString("abc").#^TC_UNSOLVED_VARIABLES_2^#
 }
-// TC_UNSOLVED_VARIABLES_2-DAG: Keyword[self]/CurrNominal: self[#BuilderStyle<_>#]; name=self
+// TC_UNSOLVED_VARIABLES_2-DAG: Keyword[self]/CurrNominal: self[#BuilderStyle<T>#]; name=self
 // TC_UNSOLVED_VARIABLES_2-DAG: Decl[InstanceVar]/CurrNominal:    count[#Int#]{{; name=.+$}}
-// TC_UNSOLVED_VARIABLES_2-DAG: Decl[InstanceMethod]/CurrNominal: addString({#(s): String#})[#BuilderStyle<_>#]{{; name=.+$}}
-// TC_UNSOLVED_VARIABLES_2-DAG: Decl[InstanceMethod]/CurrNominal: add({#(t): _#})[#BuilderStyle<_>#]{{; name=.+$}}
+// TC_UNSOLVED_VARIABLES_2-DAG: Decl[InstanceMethod]/CurrNominal: addString({#(s): String#})[#BuilderStyle<T>#]{{; name=.+$}}
+// TC_UNSOLVED_VARIABLES_2-DAG: Decl[InstanceMethod]/CurrNominal: add({#(t): T#})[#BuilderStyle<T>#]{{; name=.+$}}
 // TC_UNSOLVED_VARIABLES_2-DAG: Decl[InstanceMethod]/CurrNominal: get()[#Int#]{{; name=.+$}}
 
 func testTypeCheckWithUnsolvedVariables3() {
@@ -1123,13 +1123,13 @@ func testInterpolatedString1() {
 
 // INTERPOLATED_STRING_1-DAG: Decl[InstanceVar]/CurrNominal/TypeRelation[Convertible]:      lazyInstanceVar[#Int#]{{; name=.+$}}
 // INTERPOLATED_STRING_1-DAG: Decl[InstanceVar]/CurrNominal/TypeRelation[Convertible]:      instanceVar[#Int#]{{; name=.+$}}
-// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: instanceFunc0()[#Void#]{{; name=.+$}}
-// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: instanceFunc1({#(a): Int#})[#Void#]{{; name=.+$}}
-// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: instanceFunc2({#(a): Int#}, {#b: &Double#})[#Void#]{{; name=.+$}}
-// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: instanceFunc3({#(a): Int#}, {#(Float, Double)#})[#Void#]{{; name=.+$}}
-// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: instanceFunc4({#(a): Int?#}, {#b: Int!#}, {#c: &Int?#}, {#d: &Int!#})[#Void#]{{; name=.+$}}
-// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal:   instanceFunc5()[#Int?#]{{; name=.+$}}
-// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal:   instanceFunc6()[#Int!#]{{; name=.+$}}
+// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: instanceFunc0[#() -> ()#]; name=instanceFunc0
+// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: instanceFunc1(_:)[#(Int) -> ()#]; name=instanceFunc1(_:)
+// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: instanceFunc2(_:b:)[#(Int, inout Double) -> ()#]; name=instanceFunc2(_:b:)
+// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: instanceFunc3(_:_:)[#(Int, (Float, Double)) -> ()#]; name=instanceFunc3(_:_:)
+// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: instanceFunc4(_:b:c:d:)[#(Int?, Int?, inout Int?, inout Int?) -> ()#]; name=instanceFunc4(_:b:c:d:)
+// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: instanceFunc5()[#Int?#]; name=instanceFunc5()
+// INTERPOLATED_STRING_1-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: instanceFunc6()[#Int!#]; name=instanceFunc6()
 
 //===--- Check protocol extensions
 
@@ -1571,7 +1571,7 @@ func testDeDuped3<T : dedupP where T.T == Int>(_ x: T) {
 // PROTOCOL_EXT_DEDUP_3-DAG: Decl[InstanceMethod]/CurrNominal:   .foo()[#Int#]; name=foo()
 // PROTOCOL_EXT_DEDUP_3-DAG: Decl[InstanceVar]/CurrNominal:      .bar[#Int#]; name=bar
 // PROTOCOL_EXT_DEDUP_3-DAG: Decl[Subscript]/CurrNominal:        [{#(x): Int#}][#Int#]; name=[:]
-// PROTOCOL_EXT_DEDUP_3-DAG: Keyword[self]/CurrNominal:          .self[#T#]; name=self
+// PROTOCOL_EXT_DEDUP_3-DAG: Keyword[self]/CurrNominal:          .self[#dedupP#]; name=self
 }
 
 //===--- Check calls that may throw
diff --git a/test/IDE/complete_where_clause.swift b/test/IDE/complete_where_clause.swift
index 42cffcd9fc06c..4439ca9447be9 100644
--- a/test/IDE/complete_where_clause.swift
+++ b/test/IDE/complete_where_clause.swift
@@ -4,8 +4,8 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=GP4 | %FileCheck %s -check-prefix=TYPE1
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=GP5 | %FileCheck %s -check-prefix=TYPE1
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=GP6 | %FileCheck %s -check-prefix=EMPTY
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=FUNC_ASSOC_NODUP_1 | %FileCheck %s -check-prefix=GEN_T_ASSOC_E
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=FUNC_ASSOC_NODUP_2 | %FileCheck %s -check-prefix=GEN_T_ASSOC_E
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=FUNC_ASSOC_NODUP_1 | %FileCheck %s -check-prefix=FUNC_ASSOC_NODUP_1
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=FUNC_ASSOC_NODUP_2 | %FileCheck %s -check-prefix=FUNC_ASSOC_NODUP_2
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=FUNC_1 | %FileCheck %s -check-prefix=GEN_T
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=FUNC_2 | %FileCheck %s -check-prefix=GEN_T_DOT
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=FUNC_2_ASSOC | %FileCheck %s -check-prefix=GEN_T_ASSOC_DOT
@@ -29,9 +29,7 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=ENUM_2 | %FileCheck %s -check-prefix=GEN_T_DOT
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=ASSOC_1 | %FileCheck %s -check-prefix=P2
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=ASSOC_2 | %FileCheck %s -check-prefix=U_DOT
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=PROTOCOL | %FileCheck %s -check-prefix=PROTOCOL
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=PROTOCOL_EXT | %FileCheck %s -check-prefix=PROTOCOL
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=PROTOCOL_SELF | %FileCheck %s -check-prefix=PROTOCOL_SELF
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=NOMINAL_TYPEALIAS | %FileCheck %s -check-prefix=NOMINAL_TYPEALIAS
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=NOMINAL_TYPEALIAS_EXT | %FileCheck %s -check-prefix=NOMINAL_TYPEALIAS_EXT
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=NOMINAL_TYPEALIAS_NESTED1 | %FileCheck %s -check-prefix=NOMINAL_TYPEALIAS_NESTED1
@@ -43,6 +41,9 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=EXT_SECONDTYPE | %FileCheck %s -check-prefix=EXT_SECONDTYPE
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=WHERE_CLAUSE_WITH_EQUAL | %FileCheck %s -check-prefix=WHERE_CLAUSE_WITH_EQUAL
 
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=PROTOCOL | %FileCheck %s -check-prefix=PROTOCOL
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=PROTOCOL_SELF | %FileCheck %s -check-prefix=PROTOCOL_SELF
+
 class A1<T1, T2, T3> {}
 
 class A2<T4, T5> {}
@@ -90,11 +91,15 @@ protocol D: C {associatedtype E}
 
 func ab<T: A & B>(_ arg: T) where T.#^FUNC_ASSOC_NODUP_1^#
 
+// FUNC_ASSOC_NODUP_1: Begin completions, 2 items
+// FUNC_ASSOC_NODUP_1-NEXT: Decl[AssociatedType]/{{Super|CurrNominal}}: E; name=E
+// FUNC_ASSOC_NODUP_1-NEXT: Keyword/None:               Type[#(A & B).Type#];
+
 func ab<T: D>(_ arg: T) where T.#^FUNC_ASSOC_NODUP_2^#
 
-// GEN_T_ASSOC_E: Begin completions, 2 items
-// GEN_T_ASSOC_E-NEXT: Decl[AssociatedType]/{{Super|CurrNominal}}: E; name=E
-// GEN_T_ASSOC_E-NEXT: Keyword/None:               Type[#T.Type#];
+// FUNC_ASSOC_NODUP_2: Begin completions, 2 items
+// FUNC_ASSOC_NODUP_2-NEXT: Decl[AssociatedType]/{{Super|CurrNominal}}: E; name=E
+// FUNC_ASSOC_NODUP_2-NEXT: Keyword/None:               Type[#D.Type#];
 
 protocol Assoc {
   associatedtype Q
@@ -107,7 +112,7 @@ func f2<T>(_: T) where T.#^FUNC_2^# {}
 // GEN_T_DOT-NOT: Keyword/CurrNominal:                self[#T#];
 func f2b<T: Assoc>(_: T) where T.#^FUNC_2_ASSOC^# {}
 // GEN_T_ASSOC_DOT-DAG: Decl[AssociatedType]/{{Super|CurrNominal}}: Q;
-// GEN_T_ASSOC_DOT-DAG: Keyword/None:                       Type[#T.Type#];
+// GEN_T_ASSOC_DOT-DAG: Keyword/None:                       Type[#Assoc.Type#];
 // GEN_T_ASSOC_DOT-NOT: Keyword/CurrNominal:                self[#T#];
 func f3<T>(_: T) where T == #^FUNC_3^# {}
 func f3<T>(_: T) where T == T.#^FUNC_4^# {}
@@ -153,7 +158,7 @@ protocol P2 {
 // P2-DAG: Decl[Protocol]/Local:                       P2[#P2#]
 
 // U_DOT: Begin completions, 2 items
-// U_DOT-DAG: Keyword/None:                       Type[#Self.U.Type#];
+// U_DOT-DAG: Keyword/None:                       Type[#Assoc.Type#];
 // U_DOT-DAG: Decl[AssociatedType]/CurrNominal:   Q;
 
 protocol P3 where #^PROTOCOL^# {
@@ -179,7 +184,7 @@ protocol P4 where Self.#^PROTOCOL_SELF^# {
 // PROTOCOL_SELF-DAG: Decl[AssociatedType]/CurrNominal:   T;
 // PROTOCOL_SELF-DAG: Decl[TypeAlias]/CurrNominal:        U[#Self.T.Q#];
 // PROTOCOL_SELF-DAG: Decl[TypeAlias]/CurrNominal:        IntAlias[#Int#];
-// PROTOCOL_SELF-DAG: Keyword/None:                       Type[#Self.Type#];
+// PROTOCOL_SELF-DAG: Keyword/None:                       Type[#P4.Type#];
 
 struct TA1<T: Assoc> where #^NOMINAL_TYPEALIAS^# {
   typealias U = T.Q
@@ -191,7 +196,7 @@ extension TA1 where #^NOMINAL_TYPEALIAS_EXT^# { }
 // NOMINAL_TYPEALIAS_EXT-DAG: Decl[GenericTypeParam]/Local:       T[#T#];
 // NOMINAL_TYPEALIAS_EXT-DAG: Decl[TypeAlias]/CurrNominal:        U[#T.Q#];
 // NOMINAL_TYPEALIAS_EXT-DAG: Decl[Struct]/Local:                 TA1[#TA1<T>#];
-// NOMINAL_TYPEALIAS_EXT-DAG: Keyword[Self]/CurrNominal:          Self[#TA1<T>#];
+// NOMINAL_TYPEALIAS_EXT-DAG: Keyword[Self]/CurrNominal:          Self[#TA1<Assoc>#];
 
 struct TA2<T: Assoc> {
   struct Inner1<U> where #^NOMINAL_TYPEALIAS_NESTED1^# {
@@ -212,15 +217,15 @@ extension TA2.Inner1 where #^NOMINAL_TYPEALIAS_NESTED1_EXT^# {}
 // NOMINAL_TYPEALIAS_NESTED1_EXT: Begin completions, 5 items
 // NOMINAL_TYPEALIAS_NESTED1_EXT-DAG: Decl[GenericTypeParam]/Local:       T[#T#];
 // NOMINAL_TYPEALIAS_NESTED1_EXT-DAG: Decl[GenericTypeParam]/Local:       U[#U#];
-// NOMINAL_TYPEALIAS_NESTED1_EXT-DAG: Decl[TypeAlias]/CurrNominal:        X1[#T#];
+// NOMINAL_TYPEALIAS_NESTED1_EXT-DAG: Decl[TypeAlias]/CurrNominal:        X1[#Assoc#];
 // NOMINAL_TYPEALIAS_NESTED1_EXT-DAG: Decl[TypeAlias]/CurrNominal:        X2[#T.Q#];
-// NOMINAL_TYPEALIAS_NESTED1_EXT-DAG: Keyword[Self]/CurrNominal:          Self[#TA2<T>.Inner1<U>#];
+// NOMINAL_TYPEALIAS_NESTED1_EXT-DAG: Keyword[Self]/CurrNominal:          Self[#TA2<Assoc>.Inner1<U>#];
 extension TA2.Inner2 where #^NOMINAL_TYPEALIAS_NESTED2_EXT^# {}
 // NOMINAL_TYPEALIAS_NESTED2_EXT: Begin completions, 4 items
 // NOMINAL_TYPEALIAS_NESTED2_EXT-DAG: Decl[GenericTypeParam]/Local:       T[#T#];
-// NOMINAL_TYPEALIAS_NESTED2_EXT-DAG: Decl[TypeAlias]/CurrNominal:        X1[#T#];
+// NOMINAL_TYPEALIAS_NESTED2_EXT-DAG: Decl[TypeAlias]/CurrNominal:        X1[#Assoc#];
 // NOMINAL_TYPEALIAS_NESTED2_EXT-DAG: Decl[TypeAlias]/CurrNominal:        X2[#T.Q#];
-// NOMINAL_TYPEALIAS_NESTED2_EXT-DAG: Keyword[Self]/CurrNominal:          Self[#TA2<T>.Inner2#];
+// NOMINAL_TYPEALIAS_NESTED2_EXT-DAG: Keyword[Self]/CurrNominal:          Self[#TA2<Assoc>.Inner2#];
 
 protocol WithAssoc {
   associatedtype T: Assoc
@@ -228,7 +233,7 @@ protocol WithAssoc {
 extension WithAssoc where T.#^EXT_ASSOC_MEMBER_1^# 
 // EXT_ASSOC_MEMBER: Begin completions, 2 items
 // EXT_ASSOC_MEMBER-DAG: Decl[AssociatedType]/CurrNominal:   Q;
-// EXT_ASSOC_MEMBER-DAG: Keyword/None:                       Type[#Self.T.Type#];
+// EXT_ASSOC_MEMBER-DAG: Keyword/None:                       Type[#Assoc.Type#];
 
 extension WithAssoc where Int == T.#^EXT_ASSOC_MEMBER_2^# 
 // Same as EXT_ASSOC_MEMBER
@@ -240,4 +245,4 @@ func foo<K: WithAssoc>(_ key: K.Type) where K.#^WHERE_CLAUSE_WITH_EQUAL^# == S1
 
 // WHERE_CLAUSE_WITH_EQUAL: Begin completions, 2 items
 // WHERE_CLAUSE_WITH_EQUAL-DAG: Decl[AssociatedType]/CurrNominal:   T;
-// WHERE_CLAUSE_WITH_EQUAL-DAG: Keyword/None:                       Type[#K.Type#];
+// WHERE_CLAUSE_WITH_EQUAL-DAG: Keyword/None:                       Type[#WithAssoc.Type#];
diff --git a/test/IDE/dump_swift_lookup_tables.swift b/test/IDE/dump_swift_lookup_tables.swift
index 177aab137c397..080ac1b5a062f 100644
--- a/test/IDE/dump_swift_lookup_tables.swift
+++ b/test/IDE/dump_swift_lookup_tables.swift
@@ -41,19 +41,19 @@ import ImportAsMember
 // CHECK-NEXT:      TU: __swift
 // CHECK-NEXT:    adding:
 // CHECK-NEXT:      SNSomeStruct: SNAdding
-// CHECK-NEXT:    blue:
+// CHECK:         blue:
 // CHECK-NEXT:      SNColorChoice: SNColorBlue
 // CHECK-NEXT:    defaultValue:
 // CHECK-NEXT:      SNSomeStruct: SNSomeStructGetDefault, SNSomeStructSetDefault
-// CHECK-NEXT:    defaultX:
+// CHECK:         defaultX:
 // CHECK-NEXT:      SNSomeStruct: DefaultXValue
-// CHECK-NEXT:    foo:
+// CHECK:         foo:
 // CHECK-NEXT:      SNSomeStruct: SNSomeStructGetFoo, SNSomeStructSetFoo
-// CHECK-NEXT:    green:
+// CHECK:         green:
 // CHECK-NEXT:      SNColorChoice: SNColorGreen
 // CHECK-NEXT:    init:
 // CHECK-NEXT:      SNSomeStruct: SNCreate
-// CHECK-NEXT:    makeSomeStruct:
+// CHECK:         makeSomeStruct:
 // CHECK-NEXT:      TU: SNMakeSomeStruct, SNMakeSomeStructForX
 // CHECK-NEXT:    x:
 // CHECK-NEXT:      SNSomeStruct: X
diff --git a/test/IDE/dump_swift_lookup_tables_objc.swift b/test/IDE/dump_swift_lookup_tables_objc.swift
index 48dbf6bd59f35..6d41988a42a0a 100644
--- a/test/IDE/dump_swift_lookup_tables_objc.swift
+++ b/test/IDE/dump_swift_lookup_tables_objc.swift
@@ -1,7 +1,7 @@
 // RUN: %target-swift-ide-test -dump-importer-lookup-table -source-filename %s -import-objc-header %S/Inputs/swift_name_objc.h > %t.ide-test.log 2>&1
 // RUN: %FileCheck %s < %t.ide-test.log
 
-// RUN: %target-typecheck-verify-swift -dump-clang-lookup-tables -import-objc-header %S/Inputs/swift_name_objc.h > %t.frontend.log 2>&1
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -dump-clang-lookup-tables -import-objc-header %S/Inputs/swift_name_objc.h > %t.frontend.log 2>&1
 // RUN: %FileCheck %s < %t.frontend.log
 
 // REQUIRES: objc_interop
diff --git a/test/IDE/issue-66926.swift b/test/IDE/issue-66926.swift
new file mode 100644
index 0000000000000..365b9c1c4f21c
--- /dev/null
+++ b/test/IDE/issue-66926.swift
@@ -0,0 +1,12 @@
+// RUN: %batch-code-completion
+
+func test(_ value: Int?) {
+#if true
+  switch value {
+  case .some(let underlyingValue) where #^COMPLETE^#underlyingValue is Int:
+    break
+  }
+#endif
+}
+
+// COMPLETE: Decl[LocalVar]/Local: underlyingValue[#Int#]; name=underlyingValue
diff --git a/test/IDE/issue-80591.swift b/test/IDE/issue-80591.swift
new file mode 100644
index 0000000000000..1e113bbf426ca
--- /dev/null
+++ b/test/IDE/issue-80591.swift
@@ -0,0 +1,18 @@
+// RUN: %batch-code-completion -enable-experimental-feature LifetimeDependence
+
+// REQUIRES: swift_feature_LifetimeDependence
+
+infix operator ^^^
+
+extension Optional where Wrapped: ~Escapable & ~Copyable {
+  @lifetime(copy self) mutating func foo() -> Self { fatalError() }
+}
+
+func ^^^ <T: ~Escapable & ~Copyable> (_ x: Int, _ y: borrowing T?) {}
+
+// https://github.com/swiftlang/swift/issues/80591 - Make sure we don't crash
+// here.
+func foo() {
+  _ = 1 ^^^ .#^COMPLETE^#
+  // COMPLETE: Decl[InstanceMethod]/CurrNominal/TypeRelation[Convertible]: foo({#(self): &Optional<~Copyable & ~Escapable>#})[#() -> Optional<~Copyable & ~Escapable>#]; name=foo(:)
+}
diff --git a/test/IDE/newtype.swift b/test/IDE/newtype.swift
index 08945a1cd44cb..37f7af552bacf 100644
--- a/test/IDE/newtype.swift
+++ b/test/IDE/newtype.swift
@@ -2,7 +2,7 @@
 // RUN: %build-clang-importer-objc-overlays
 // RUN: %target-swift-ide-test(mock-sdk: %clang-importer-sdk-nosource) -I %t -I %S/Inputs/custom-modules -print-module -source-filename %s -module-to-print=Newtype -skip-unavailable -access-filter-public > %t.printed.A.txt
 // RUN: %FileCheck %s -check-prefix=PRINT -strict-whitespace < %t.printed.A.txt
-// RUN: %target-typecheck-verify-swift -sdk %clang-importer-sdk -I %S/Inputs/custom-modules -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -sdk %clang-importer-sdk -I %S/Inputs/custom-modules -I %t
 // REQUIRES: objc_interop
 
 // PRINT-LABEL: struct ErrorDomain : _ObjectiveCBridgeable, Hashable, Equatable, _SwiftNewtypeWrapper, RawRepresentable, @unchecked Sendable {
diff --git a/test/IDE/objc_send_collector_1.swift b/test/IDE/objc_send_collector_1.swift
index a0c9166d069b5..a71b5d48bb287 100644
--- a/test/IDE/objc_send_collector_1.swift
+++ b/test/IDE/objc_send_collector_1.swift
@@ -4,10 +4,10 @@
 // RUN: %target-swift-frontend  -I %t/lib/swift -typecheck %s %S/Inputs/objc_send_collector_2.swift -module-name main -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE
 // RUN: cat %t/.SWIFT_FINE_DEPENDENCY_TRACE.json | %{python} -c 'import json, sys; json.dump(json.loads(sys.stdin.read()), sys.stdout, sort_keys=True, indent=2)' | %FileCheck %s
 
-// RUN: SWIFT_COMPILER_FINE_GRAINED_TRACE_PATH=%t/given_trace.json %target-swift-frontend  -I %t/lib/swift -typecheck %s %S/Inputs/objc_send_collector_2.swift -module-name main -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE
+// RUN: env SWIFT_COMPILER_FINE_GRAINED_TRACE_PATH=%t/given_trace.json %target-swift-frontend  -I %t/lib/swift -typecheck %s %S/Inputs/objc_send_collector_2.swift -module-name main -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE
 // RUN: cat %t/given_trace.json | %{python} -c 'import json, sys; json.dump(json.loads(sys.stdin.read()), sys.stdout, sort_keys=True, indent=2)' | %FileCheck %s
 
-// RUN: SWIFT_COMPILER_FINE_GRAINED_TRACE_PATH=%t/given_trace_2.json %target-swift-frontend  -I %t/lib/swift -emit-module %s %S/Inputs/objc_send_collector_2.swift -module-name main -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE -enable-library-evolution
+// RUN: env SWIFT_COMPILER_FINE_GRAINED_TRACE_PATH=%t/given_trace_2.json %target-swift-frontend  -I %t/lib/swift -emit-module %s %S/Inputs/objc_send_collector_2.swift -module-name main -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE -enable-library-evolution
 // RUN: not ls %t/given_trace_2.json
 
 
@@ -16,10 +16,10 @@
 // RUN: echo "  ModuleName:" >> %t/blocklist.yml
 // RUN: echo "    - FooBar" >> %t/blocklist.yml
 
-// RUN: SWIFT_COMPILER_FINE_GRAINED_TRACE_PATH=%t/given_trace_3.json %target-swift-frontend  -I %t/lib/swift -typecheck %s %S/Inputs/objc_send_collector_2.swift -module-name FooBar -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE -blocklist-file %t/blocklist.yml
+// RUN: env SWIFT_COMPILER_FINE_GRAINED_TRACE_PATH=%t/given_trace_3.json %target-swift-frontend  -I %t/lib/swift -typecheck %s %S/Inputs/objc_send_collector_2.swift -module-name FooBar -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE -blocklist-file %t/blocklist.yml
 // RUN: cat %t/given_trace_3.json | %{python} -c 'import json, sys; json.dump(json.loads(sys.stdin.read()), sys.stdout, sort_keys=True, indent=2)' | %FileCheck %s  --check-prefix=CHECK-BLOCKED
 
-// RUN: SWIFT_COMPILER_FINE_GRAINED_TRACE_PATH=%t/given_trace_4.json %target-swift-frontend  -I %t/lib/swift -typecheck %s %S/Inputs/objc_send_collector_2.swift -module-name FooBar -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE -disable-fine-module-tracing
+// RUN: env SWIFT_COMPILER_FINE_GRAINED_TRACE_PATH=%t/given_trace_4.json %target-swift-frontend  -I %t/lib/swift -typecheck %s %S/Inputs/objc_send_collector_2.swift -module-name FooBar -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE -disable-fine-module-tracing
 // RUN: not ls %t/given_trace_4.json
 
 // REQUIRES: objc_interop
diff --git a/test/IDE/pr-83704.swift b/test/IDE/pr-83704.swift
new file mode 100644
index 0000000000000..88a1b2fcbbb7b
--- /dev/null
+++ b/test/IDE/pr-83704.swift
@@ -0,0 +1,102 @@
+// RUN: %batch-code-completion
+
+@resultBuilder
+struct Builder0 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+  static func buildArray<T>(_ components: [T]) -> T { components.first! }
+}
+@resultBuilder
+struct Builder1 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder2 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder3 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder4 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder5 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder6 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder7 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder8 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder9 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+
+protocol P0 {}
+protocol P1 {}
+protocol P2 {}
+protocol P3 {}
+protocol P4 {}
+protocol P5 {}
+protocol P6 {}
+protocol P7 {}
+protocol P8 {}
+protocol P9 {}
+
+struct S<T> {}
+extension S: P0 where T : P0 { init<U>(@Builder0 fn: () -> U) {} }
+extension S: P1 where T : P1 { init<U>(@Builder1 fn: () -> U) {} }
+extension S: P2 where T : P2 { init<U>(@Builder2 fn: () -> U) {} }
+extension S: P3 where T : P3 { init<U>(@Builder3 fn: () -> U) {} }
+extension S: P4 where T : P4 { init<U>(@Builder4 fn: () -> U) {} }
+extension S: P5 where T : P5 { init<U>(@Builder5 fn: () -> U) {} }
+extension S: P6 where T : P6 { init<U>(@Builder6 fn: () -> U) {} }
+extension S: P7 where T : P7 { init<U>(@Builder7 fn: () -> U) {} }
+extension S: P8 where T : P8 { init<U>(@Builder8 fn: () -> U) {} }
+extension S: P9 where T : P9 { init<U>(@Builder9 fn: () -> U) {} }
+
+struct K {
+  var foo: Int
+}
+
+// Make sure we ignore all the result builders that cannot handle for loops
+// and just use Builder0. There's also no way 'T' can be inferred here but
+// that doesn't really matter for this test.
+func foo(_ ks: [K]) {
+  S {
+    for k0 in ks {
+      S {
+        for k1 in ks {
+          S {
+            for k2 in ks {
+              S {
+                for k3 in ks {
+                  S {
+                    for k4 in ks {
+                      S {
+                        for k5 in ks {
+                          k5.#^COMPLETE^#
+                          // COMPLETE: Decl[InstanceVar]/CurrNominal: foo[#Int#]; name=foo
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/test/IDE/pr83369.swift b/test/IDE/pr83369.swift
new file mode 100644
index 0000000000000..6fcd79c8ed64c
--- /dev/null
+++ b/test/IDE/pr83369.swift
@@ -0,0 +1,9 @@
+// RUN: %batch-code-completion -module-name main
+
+extension Int {}
+
+// Make sure we can resolve P here.
+protocol P<X> where X: main.#^COMPLETE^# {
+  associatedtype X
+}
+// COMPLETE: Decl[Protocol]/CurrModule: P[#P#]; name=P
diff --git a/test/IDE/print_ast_tc_decls.swift b/test/IDE/print_ast_tc_decls.swift
index b0cd2f4297b54..bbafcae286833 100644
--- a/test/IDE/print_ast_tc_decls.swift
+++ b/test/IDE/print_ast_tc_decls.swift
@@ -8,7 +8,7 @@
 // FIXME: END -enable-source-import hackaround
 //
 // This file should not have any syntax or type checker errors.
-// RUN: %target-swift-frontend(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) -swift-version 4 -D ERRORS -typecheck -verify %s -F %S/Inputs/mock-sdk -enable-objc-interop -disable-objc-attr-requires-foundation-module
+// RUN: %target-swift-frontend(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) -swift-version 4 -D ERRORS -typecheck -verify -verify-ignore-unrelated %s -F %S/Inputs/mock-sdk -enable-objc-interop -disable-objc-attr-requires-foundation-module
 //
 // RUN: %target-swift-ide-test(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) -swift-version 4 -skip-deinit=false -print-ast-typechecked -source-filename %s -F %S/Inputs/mock-sdk -function-definitions=false -prefer-type-repr=false -print-implicit-attrs=true -enable-objc-interop -disable-objc-attr-requires-foundation-module > %t.printed.txt
 // RUN: %FileCheck %s -check-prefix=PASS_COMMON -strict-whitespace < %t.printed.txt
diff --git a/test/IDE/print_ast_tc_decls_canonical_versions.swift b/test/IDE/print_ast_tc_decls_canonical_versions.swift
new file mode 100644
index 0000000000000..ca30d5d63e57c
--- /dev/null
+++ b/test/IDE/print_ast_tc_decls_canonical_versions.swift
@@ -0,0 +1,21 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -typecheck %s
+// RUN: %target-swift-ide-test -skip-deinit=false -print-ast-typechecked -source-filename %s -function-definitions=false -prefer-type-repr=false -print-implicit-attrs=true > %t.printed.txt
+// RUN: %FileCheck %s -check-prefix=PASS_COMMON -strict-whitespace < %t.printed.txt
+
+@available(iOS 10.16, OSX 10.16, *)
+func introduced10_16() {}
+// PASS_COMMON: {{^}}@available(iOS 10.16, macOS 11.0, *){{$}}
+// PASS_COMMON-NEXT: {{^}}func introduced10_16(){{$}}
+
+@available(macOS 16.0, iOS 19.0, macCatalyst 19.0, watchOS 12.0, tvOS 19.0, visionOS 3.0, *)
+func introducedInVersionsMappingTo26_0() {}
+// FIXME: visionOS and macCatalyst are missing
+// PASS_COMMON: {{^}}@available(macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, *){{$}}
+// PASS_COMMON-NEXT: {{^}}func introducedInVersionsMappingTo26_0(){{$}}
+
+@available(macOS 18.0, iOS 21.0, macCatalyst 21.0, watchOS 14.0, tvOS 21.0, visionOS 5.0, *)
+func introducedInVersionsMappingTo28_0() {}
+// FIXME: visionOS and macCatalyst are missing
+// PASS_COMMON: {{^}}@available(macOS 28.0, iOS 28.0, watchOS 28.0, tvOS 28.0, *){{$}}
+// PASS_COMMON-NEXT: {{^}}func introducedInVersionsMappingTo28_0(){{$}}
diff --git a/test/IDE/print_ast_tc_decls_errors.swift b/test/IDE/print_ast_tc_decls_errors.swift
index f84a590edb69c..1f5a88b83fbf5 100644
--- a/test/IDE/print_ast_tc_decls_errors.swift
+++ b/test/IDE/print_ast_tc_decls_errors.swift
@@ -1,6 +1,6 @@
 // Verify errors in this file to ensure that parse and type checker errors
 // occur where we expect them.
-// RUN: %target-typecheck-verify-swift -show-diagnostics-after-fatal
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -show-diagnostics-after-fatal
 
 // RUN: %target-swift-ide-test -print-ast-typechecked -source-filename %s -prefer-type-repr=false > %t.printed.txt
 // RUN: %FileCheck %s -strict-whitespace < %t.printed.txt
diff --git a/test/IDE/print_ast_tc_decls_macosx_canonical_versions.swift b/test/IDE/print_ast_tc_decls_macosx_canonical_versions.swift
deleted file mode 100644
index f51f8f2e173ca..0000000000000
--- a/test/IDE/print_ast_tc_decls_macosx_canonical_versions.swift
+++ /dev/null
@@ -1,16 +0,0 @@
-// RUN: %empty-directory(%t)
-//
-//
-// RUN: %target-swift-frontend(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) -swift-version 4 -typecheck -verify %s -F %S/Inputs/mock-sdk -enable-objc-interop -disable-objc-attr-requires-foundation-module
-//
-// RUN: %target-swift-ide-test(mock-sdk: -sdk %S/../Inputs/clang-importer-sdk -I %t) -swift-version 4 -skip-deinit=false -print-ast-typechecked -source-filename %s -F %S/Inputs/mock-sdk -function-definitions=false -prefer-type-repr=false -print-implicit-attrs=true -enable-objc-interop -disable-objc-attr-requires-foundation-module > %t.printed.txt
-// RUN: %FileCheck %s -check-prefix=PASS_COMMON -strict-whitespace < %t.printed.txt
-
-
-// FIXME: rdar://problem/19648117 Needs splitting objc parts out
-// REQUIRES: objc_interop
-
-@available(iOS 10.16, OSX 10.16, *)
-func introduced10_16() {}
-// PASS_COMMON: {{^}}@available(iOS 10.16, macOS 11.0, *){{$}}
-// PASS_COMMON-NEXT: {{^}}func introduced10_16(){{$}}
diff --git a/test/IDE/print_clang_bool_bridging.swift b/test/IDE/print_clang_bool_bridging.swift
index d7cee05380dff..bb6306babce53 100644
--- a/test/IDE/print_clang_bool_bridging.swift
+++ b/test/IDE/print_clang_bool_bridging.swift
@@ -1,7 +1,8 @@
 // RUN: %empty-directory(%t)
 
 // RUN: %target-swift-ide-test -print-module -source-filename %s -module-to-print=BoolBridgingTests -function-definitions=false -skip-unavailable -F %S/Inputs/mock-sdk > %t.txt
-// RUN: diff -u <(tail -n +9 %s) %t.txt
+// RUN: tail -n +10 %s > %t/a
+// RUN: diff -u %t/a %t.txt
 
 // REQUIRES: objc_interop
 
diff --git a/test/IDE/print_clang_framework_with_overlay.swift b/test/IDE/print_clang_framework_with_overlay.swift
index a5be7186f4495..55e61e8025d6a 100644
--- a/test/IDE/print_clang_framework_with_overlay.swift
+++ b/test/IDE/print_clang_framework_with_overlay.swift
@@ -10,7 +10,5 @@ import FooOverlay
 // CHECK: @_exported import Foo
 // CHECK: @_exported import struct Foo.FooStruct1
 // CHECK: @_exported import Foo.FooSub
-// CHECK: @_exported import func Foo.FooSub.fooSubFunc1
-// FIXME: this duplicate import is silly, but not harmful.
 // CHECK: @_exported import func Foo.fooSubFunc1
 // CHECK: func fooSubOverlayFunc1(x: Int32) -> Int32
diff --git a/test/IDE/print_clang_swift_name.swift b/test/IDE/print_clang_swift_name.swift
index 499c876fdd758..2a7a97ec18851 100644
--- a/test/IDE/print_clang_swift_name.swift
+++ b/test/IDE/print_clang_swift_name.swift
@@ -1,7 +1,8 @@
 // RUN: %empty-directory(%t)
 
 // RUN: %target-swift-ide-test(mock-sdk: %clang-importer-sdk) -print-module -source-filename %s -module-to-print=SwiftNameTests -function-definitions=false -F %S/Inputs/mock-sdk > %t.txt
-// RUN: diff -u <(tail -n +9 %s) %t.txt
+// RUN: tail -n +10 %s > %t/a
+// RUN: diff -u %t/a %t.txt
 
 // REQUIRES: objc_interop
 
diff --git a/test/IDE/print_lifetime_attr.swift b/test/IDE/print_lifetime_attr.swift
new file mode 100644
index 0000000000000..cf1e91205c358
--- /dev/null
+++ b/test/IDE/print_lifetime_attr.swift
@@ -0,0 +1,58 @@
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_LifetimeDependence
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-ide-test -enable-experimental-feature Lifetimes -enable-experimental-feature LifetimeDependence -print-swift-file-interface -source-filename %t/test.swift > %t/interface.txt
+// RUN: diff %t/interface.txt %t/interface.txt.expected
+
+//--- test.swift
+public struct S : ~Escapable {
+    @_lifetime(immortal)
+    init() {}
+}
+
+@_lifetime(foo: copy foo)
+public func fooFunc(_ foo: inout S) {}
+
+@_lifetime(&bar)
+public func barFunc(_ bar: inout S) -> S {
+    return bar
+}
+
+@_lifetime(`func`: copy `func`)
+public func funcFunc(func: inout S) {}
+
+public struct T : ~Escapable {
+    let s: S
+    @_lifetime(borrow self)
+    func selfFunc() -> S { return s }
+    @_lifetime(borrow `self`)
+    func selfFunc2(`self`: S) -> S { return `self` }
+}
+
+//--- interface.txt.expected
+
+public struct S : ~Escapable {
+
+    @_lifetime(immortal)
+    internal init()
+}
+@_lifetime(foo: copy foo)
+public func fooFunc(_ foo: inout S)
+@_lifetime(&bar)
+public func barFunc(_ bar: inout S) -> S
+@_lifetime(`func`: copy `func`)
+public func funcFunc(func: inout S)
+
+public struct T : ~Escapable {
+
+    internal let s: S
+
+    @_lifetime(borrow self)
+    internal func selfFunc() -> S
+
+    @_lifetime(borrow `self`)
+    internal func selfFunc2(self: S) -> S
+}
diff --git a/test/IDE/print_omit_needless_words.swift b/test/IDE/print_omit_needless_words.swift
index 4a73c02eba132..924b65a1fa03a 100644
--- a/test/IDE/print_omit_needless_words.swift
+++ b/test/IDE/print_omit_needless_words.swift
@@ -314,7 +314,7 @@
 // CHECK-OMIT-NEEDLESS-WORDS-NEXT: @available(swift, obsoleted: 3, renamed: "veryCarefullyBurn()")
 // CHECK-OMIT-NEEDLESS-WORDS-NEXT: func veryCarefullyBurnGarbage4DTypeRefMask_t()
 
-// CHECK-OMIT-NEEDLESS-WORDS-DIAGS: inconsistent Swift name for Objective-C property 'conflictingProp1' in 'OMWSub' ('waggleProp1' in 'OMWWaggle' vs. 'wiggleProp1' in 'OMWSuper')
+// CHECK-OMIT-NEEDLESS-WORDS-DIAGS: inconsistent Swift name for Objective-C property 'conflictingProp1' in 'OMWSub' ('waggleProp1' in 'OMWWaggle' vs. 'wiggleProp1' in 'OMWSuper') [#ClangDeclarationImport]
 
 // Don't drop the 'error'.
 // CHECK-ERRORS: func tryAndReturnError(_: ()) throws
diff --git a/test/IDE/print_synthesized_extensions.swift b/test/IDE/print_synthesized_extensions.swift
index 37a0a21d02920..abab4d10c5f1f 100644
--- a/test/IDE/print_synthesized_extensions.swift
+++ b/test/IDE/print_synthesized_extensions.swift
@@ -241,9 +241,9 @@ extension S13 : P5 {
 }
 
 // CHECK1: <synthesized>extension <ref:Struct>S1</ref> where <ref:GenericTypeParam>T</ref> : <ref:module>print_synthesized_extensions</ref>.<ref:Protocol>P2</ref> {
-// CHECK1-NEXT:     <decl:Func>public func <loc>p2member()</loc></decl>
 // CHECK1-NEXT:     <decl:Func>public func <loc>ef1(<decl:Param>t: <ref:GenericTypeParam>T</ref></decl>)</loc></decl>
 // CHECK1-NEXT:     <decl:Func>public func <loc>ef2(<decl:Param>t: <ref:module>print_synthesized_extensions</ref>.<ref:Struct>S2</ref></decl>)</loc></decl>
+// CHECK1-NEXT:     <decl:Func>public func <loc>p2member()</loc></decl>
 // CHECK1-NEXT: }</synthesized>
 
 // CHECK2:  <synthesized>extension <ref:Struct>S1</ref> where <ref:GenericTypeParam>T</ref> : <ref:module>print_synthesized_extensions</ref>.<ref:Protocol>P3</ref>  {
@@ -410,4 +410,4 @@ extension S14 : P14 where repeat each T: Hashable {}
 
 // CHECK17:      <synthesized>extension <ref:Struct>S14</ref> {
 // CHECK17-NEXT:   <decl:Func>public func <loc>foo<each <ref:GenericTypeParam>T</ref>>(<decl:Param>_: repeat each <ref:GenericTypeParam>T</ref></decl>)</loc> where Pack{repeat each <ref:GenericTypeParam>T</ref>} : <ref:Protocol>Equatable</ref></decl>
-// CHECK17-NEXT: }</synthesized>
\ No newline at end of file
+// CHECK17-NEXT: }</synthesized>
diff --git a/test/IDE/print_synthesized_extensions_generics.swift b/test/IDE/print_synthesized_extensions_generics.swift
index b7fdbec74ec72..72d2f5bb30309 100644
--- a/test/IDE/print_synthesized_extensions_generics.swift
+++ b/test/IDE/print_synthesized_extensions_generics.swift
@@ -85,3 +85,21 @@ extension G : P2 {}
 // CHECK:      extension P2 where Self.T.T : print_synthesized_extensions_generics.A {
 // CHECK-NEXT:   func blah()
 // CHECK-NEXT: }
+
+public protocol P3 {
+  associatedtype A
+}
+public protocol P4 {
+  associatedtype B: P3
+}
+
+public struct S1<A> {}
+
+// Make sure we don't crash. Unfortunately we don't yet correctly output these
+// though.
+extension S1: P4 where A: P4, A.B.A == A {
+  public typealias B = A.B
+}
+extension P3 where A: P4, A.B.A == A {
+  public func foo() {}
+}
diff --git a/test/IDE/range_info_basics.swift b/test/IDE/range_info_basics.swift
index 29de1fe8dc4d8..1f9f0107b0b7a 100644
--- a/test/IDE/range_info_basics.swift
+++ b/test/IDE/range_info_basics.swift
@@ -371,7 +371,7 @@ func testPropertyWrapper() {
 // CHECK13-NEXT:     b = b.bigEndian.bigEndian.byteSwapped
 // CHECK13-NEXT:     print(b + c)</Content>
 // CHECK13-NEXT: <Type>Void</Type>
-// CHECK13-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator=0</Context>
+// CHECK13-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator={{[0-9]+}}</Context>
 // CHECK13-NEXT: <Declared>a</Declared><OutscopeReference>false</OutscopeReference>
 // CHECK13-NEXT: <Declared>b</Declared><OutscopeReference>false</OutscopeReference>
 // CHECK13-NEXT: <Declared>c</Declared><OutscopeReference>false</OutscopeReference>
@@ -396,7 +396,7 @@ func testPropertyWrapper() {
 // CHECK14-NEXT:       return 1
 // CHECK14-NEXT:     }()</Content>
 // CHECK14-NEXT: <Type>Int</Type>
-// CHECK14-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator=0</Context>
+// CHECK14-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator={{[0-9]+}}</Context>
 // CHECK14-NEXT: <Declared>a</Declared><OutscopeReference>false</OutscopeReference>
 // CHECK14-NEXT: <Declared>b</Declared><OutscopeReference>false</OutscopeReference>
 // CHECK14-NEXT: <Declared>c</Declared><OutscopeReference>false</OutscopeReference>
@@ -418,7 +418,7 @@ func testPropertyWrapper() {
 // CHECK15-NEXT:       let c = a.byteSwapped
 // CHECK15-NEXT:       b = b.bigEndian.bigEndian.byteSwapped</Content>
 // CHECK15-NEXT: <Type>Void</Type>
-// CHECK15-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator=0.explicit closure discriminator=0</Context>
+// CHECK15-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator={{[0-9]+}}.explicit closure discriminator={{[0-9]+}}</Context>
 // CHECK15-NEXT: <Declared>a</Declared><OutscopeReference>false</OutscopeReference>
 // CHECK15-NEXT: <Declared>b</Declared><OutscopeReference>true</OutscopeReference>
 // CHECK15-NEXT: <Declared>c</Declared><OutscopeReference>true</OutscopeReference>
@@ -435,7 +435,7 @@ func testPropertyWrapper() {
 // CHECK16-NEXT:       print(b + c)
 // CHECK16-NEXT:       return 1</Content>
 // CHECK16-NEXT: <Type>Int</Type>
-// CHECK16-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator=0.explicit closure discriminator=0</Context>
+// CHECK16-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator={{[0-9]+}}.explicit closure discriminator={{[0-9]+}}</Context>
 // CHECK16-NEXT: <Declared>a</Declared><OutscopeReference>false</OutscopeReference>
 // CHECK16-NEXT: <Declared>b</Declared><OutscopeReference>false</OutscopeReference>
 // CHECK16-NEXT: <Declared>c</Declared><OutscopeReference>false</OutscopeReference>
@@ -448,7 +448,7 @@ func testPropertyWrapper() {
 // CHECK17: <Kind>SingleExpression</Kind>
 // CHECK17-NEXT: <Content>print(b + c)</Content>
 // CHECK17-NEXT: <Type>()</Type>
-// CHECK17-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator=0.explicit closure discriminator=0</Context>
+// CHECK17-NEXT: <Context>swift_ide_test.(file).foo6().explicit closure discriminator={{[0-9]+}}.explicit closure discriminator={{[0-9]+}}</Context>
 // CHECK17-NEXT: <Referenced>b</Referenced><Type>Int</Type>
 // CHECK17-NEXT: <Referenced>c</Referenced><Type>Int</Type>
 // CHECK17-NEXT: <ASTNodes>1</ASTNodes>
@@ -497,7 +497,7 @@ func testPropertyWrapper() {
 // CHECK27-NEXT:     foo9(1, 2)</Content>
 // CHECK27-NEXT: <Type>Void</Type>
 // CHECK27-NEXT: <Context>swift_ide_test.(file).foo9(_:_:)</Context>
-// CHECK27-NEXT: <Referenced>foo9</Referenced><Type>(Int, Int) -> Int</Type>
+// CHECK27-NEXT: <Referenced>foo9</Referenced><Type>(_ a: Int, _ b: Int) -> Int</Type>
 // CHECK27-NEXT: <ASTNodes>2</ASTNodes>
 // CHECK27-NEXT: <end>
 
diff --git a/test/IDE/range_info_expr.swift b/test/IDE/range_info_expr.swift
index 2f38552d4fd6a..4a1ec28abe681 100644
--- a/test/IDE/range_info_expr.swift
+++ b/test/IDE/range_info_expr.swift
@@ -109,7 +109,7 @@ func bar(x: C2 = .main) {}
 // CHECK-MTEE-EXPR-3-NEXT: <Content>{ escapable in
 // CHECK-MTEE-EXPR-3-NEXT:     _ = escapable
 // CHECK-MTEE-EXPR-3-NEXT:   }</Content>
-// CHECK-MTEE-EXPR-3-NEXT: <Type>(@escaping (Int) -> Void) -> ()</Type><Exit>false</Exit>
+// CHECK-MTEE-EXPR-3-NEXT: <Type>(_ escapable: @escaping (Int) -> Void) -> ()</Type><Exit>false</Exit>
 // CHECK-MTEE-EXPR-3-NEXT: <Context>swift_ide_test.(file).testWithoutActuallyEscaping(closure:)</Context>
 // CHECK-MTEE-EXPR-3-NEXT: <Declared>escapable</Declared><OutscopeReference>false</OutscopeReference>
 // CHECK-MTEE-EXPR-3-NEXT: <Referenced>escapable</Referenced><Type>(Int) -> Void</Type>
diff --git a/test/IDE/signature_help_closure_param.swift b/test/IDE/signature_help_closure_param.swift
new file mode 100644
index 0000000000000..9a04515e53d88
--- /dev/null
+++ b/test/IDE/signature_help_closure_param.swift
@@ -0,0 +1,7 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=CLOSURE_PARAM -source-filename=%s | %FileCheck %s --check-prefix=CLOSURE_PARAM
+
+func apply<Value, Result>(value: Value, body: (Value) -> Result) -> Result {
+  return body(#^CLOSURE_PARAM^#)
+  // CLOSURE_PARAM:     Begin signatures, 1 items
+  // CLOSURE_PARAM-DAG: Signature[Active]: body(<param active>Value</param>) -> Result
+}
diff --git a/test/IDE/signature_help_currying.swift b/test/IDE/signature_help_currying.swift
new file mode 100644
index 0000000000000..910a781f37a38
--- /dev/null
+++ b/test/IDE/signature_help_currying.swift
@@ -0,0 +1,74 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=CURRY_TOPLEVEL -source-filename=%s | %FileCheck %s --check-prefix=CURRY_TOPLEVEL
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=CURRY_MEMBER_PARTIAL -source-filename=%s | %FileCheck %s --check-prefix=CURRY_MEMBER_PARTIAL
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=CURRY_MEMBER_FULL -source-filename=%s | %FileCheck %s --check-prefix=CURRY_MEMBER_FULL
+
+struct Adder {
+  func add(_ x: Int, to y: Int) -> Int {
+    return x + y
+  }
+
+  func add(oneTo x: inout Int) {
+    x += 1
+  }
+
+  func add<T: AdditiveArithmetic>(_ x: T, to y: T) -> T {
+    return x + y
+  }
+
+  func add(first: Double!, second: Float, third: Int) -> Double {
+    return first + Double(second) + Double(third)
+  }
+
+  func add(arg1 param1: Double, arg2: Float, arg3 param3: Int) -> Double {
+    return param1 + Double(arg2) + Double(param3)
+  }
+
+  func add(numbers: Double...) -> Double {
+    return numbers.reduce(into: 0) { $0 += $1 }
+  }
+
+  func add(x: Int, y: Int, with adder: (Int, Int) throws -> Int) rethrows -> Int! {
+    return try adder(x, y)
+  }
+
+  func add(x: Int) -> (Int) -> Int {
+    return { (y: Int) in x + y }
+  }
+}
+
+func topLevelCurried(x: Int) -> (Double) -> (String) -> Void {
+  fatalError()
+}
+
+func testCurryTopLevel() {
+  topLevelCurried(x: 1)(#^CURRY_TOPLEVEL^#)
+  // CURRY_TOPLEVEL:     Begin signatures, 1 items
+  // CURRY_TOPLEVEL-DAG: Signature[Active]: (<param active>Double</param>) -> (String) -> Void
+}
+
+func testCurryMemberPartial() {
+  Adder.add(#^CURRY_MEMBER_PARTIAL^#)
+  // CURRY_MEMBER_PARTIAL:     Begin signatures, 8 items
+  // CURRY_MEMBER_PARTIAL-DAG: Signature[Active]: add(<param name="self" active>_ self: Adder</param>) -> (Int, Int) -> Int
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (inout Int) -> ()
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (AdditiveArithmetic, AdditiveArithmetic) -> AdditiveArithmetic
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Double?, Float, Int) -> Double
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Double, Float, Int) -> Double
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Double...) -> Double
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Int, Int, (Int, Int) throws -> Int) throws -> Int?
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Int) -> (Int) -> Int
+}
+
+func testCurryMemberFull() {
+  let adder = Adder()
+  Adder.add(adder)(#^CURRY_MEMBER_FULL^#)
+  // CURRY_MEMBER_FULL:     Begin signatures, 8 items
+  // CURRY_MEMBER_FULL-DAG: Signature[Active]: (<param name="x" active>_ x: Int</param>, <param name="y">to: Int</param>) -> Int
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="x" active>oneTo: inout Int</param>)
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="x" active>_ x: AdditiveArithmetic</param>, <param name="y">to: AdditiveArithmetic</param>) -> AdditiveArithmetic
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="first" active>first: Double!</param>, <param name="second">second: Float</param>, <param name="third">third: Int</param>) -> Double
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="param1" active>arg1: Double</param>, <param name="arg2">arg2: Float</param>, <param name="param3">arg3: Int</param>) -> Double
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="numbers" active>numbers: Double...</param>) -> Double
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="x" active>x: Int</param>, <param name="y">y: Int</param>, <param name="adder">with: (Int, Int) throws -> Int</param>) throws -> Int!
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="x" active>x: Int</param>) -> (Int) -> Int
+}
diff --git a/test/IDE/signature_help_default_args.swift b/test/IDE/signature_help_default_args.swift
new file mode 100644
index 0000000000000..0e07b2db06e02
--- /dev/null
+++ b/test/IDE/signature_help_default_args.swift
@@ -0,0 +1,34 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=DEFAULT_ARGS -source-filename=%s | %FileCheck %s --check-prefix=DEFAULT_ARGS
+
+func add(_ x: Int = 10, to y: Int) -> Int {}
+
+func add(oneTo x: inout Int) {}
+
+func add(_ x: Int, to y: Int? = nil) -> String {}
+
+func add(first: Double!, second: Float = .pi, third: Int) -> Double {}
+
+struct S {
+  let a: Bool
+}
+
+func add(s: S = S(a: false)) -> Double {}
+
+func add(x: Int, y: Int, with adder: (Int, Int) -> Int = { $0 + $1 }) -> Int {}
+
+let importantValue = 42
+
+func add(x: Int = importantValue) {}
+
+func add(x: Int, line: UInt = #line, file: StaticString = #file) {}
+
+add(#^DEFAULT_ARGS^#)
+// DEFAULT_ARGS:     Begin signatures, 8 items
+// DEFAULT_ARGS-DAG: Signature[Active]: add(<param name="x" active>_ x: Int = 10</param>, <param name="y">to: Int</param>) -> Int
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>oneTo: inout Int</param>)
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>_ x: Int</param>, <param name="y">to: Int? = nil</param>) -> String
+// DEFAULT_ARGS-DAG: Signature: add(<param name="first" active>first: Double!</param>, <param name="second">second: Float = .pi</param>, <param name="third">third: Int</param>) -> Double
+// DEFAULT_ARGS-DAG: Signature: add(<param name="s" active>s: S = S(a: false)</param>) -> Double
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>x: Int</param>, <param name="y">y: Int</param>, <param name="adder">with: (Int, Int) -> Int = { $0 + $1 }</param>) -> Int
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>x: Int = importantValue</param>)
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>x: Int</param>, <param name="line">line: UInt = #line</param>, <param name="file">file: StaticString = #file</param>)
diff --git a/test/IDE/signature_help_doc.swift b/test/IDE/signature_help_doc.swift
new file mode 100644
index 0000000000000..6c741b34051c5
--- /dev/null
+++ b/test/IDE/signature_help_doc.swift
@@ -0,0 +1,21 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=DOC -source-filename=%s | %FileCheck %s --check-prefix=DOC
+
+/// Adds two integers.
+///
+/// - Parameters:
+///   - x: The first integer to add.
+///   - y: The second integer to add.
+///
+/// Usage:
+/// ```swift
+/// add(1, to: 2) // 3
+/// ```
+///
+/// - Returns: The sum of the two integers.
+func add(_ x: Int, to y: Int) -> Int {
+  return x + y
+}
+
+add(#^DOC^#)
+// DOC:     Begin signatures, 1 items
+// DOC-DAG: Signature[Active]: add(<param name="x" active>_ x: Int</param>, <param name="y">to: Int</param>) -> Int; Documentation=Adds two integers.\n\n- Parameters:\n  - x: The first integer to add.\n  - y: The second integer to add.\n\nUsage:\n```swift\nadd(1, to: 2) // 3\n```\n\n- Returns: The sum of the two integers.
diff --git a/test/IDE/signature_help_enum_case.swift b/test/IDE/signature_help_enum_case.swift
new file mode 100644
index 0000000000000..b315676f4f518
--- /dev/null
+++ b/test/IDE/signature_help_enum_case.swift
@@ -0,0 +1,19 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=LABELLED -source-filename=%s | %FileCheck %s --check-prefix=LABELLED
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=UNLABELLED -source-filename=%s | %FileCheck %s --check-prefix=UNLABELLED
+
+enum Barcode {
+  case upc(numberSystem: Int, manufacturer: Int, product: Int, check: Int)
+  case qrCode(String)
+}
+
+func testLabeled() {
+  Barcode.upc(#^LABELLED^#, manufacturer: 85909, product: 51226, check: 3)
+  // LABELLED:     Begin signatures, 1 items
+  // LABELLED-DAG: Signature[Active]: upc(<param name="numberSystem" active>numberSystem: Int</param>, <param name="manufacturer">manufacturer: Int</param>, <param name="product">product: Int</param>, <param name="check">check: Int</param>) -> Barcode
+}
+
+func testUnlabled() {
+  Barcode.qrCode(#^UNLABELLED^#)
+  // UNLABELLED:     Begin signatures, 1 items
+  // UNLABELLED-DAG: Signature[Active]: qrCode(<param active>String</param>) -> Barcode
+}
diff --git a/test/IDE/signature_help_init.swift b/test/IDE/signature_help_init.swift
new file mode 100644
index 0000000000000..dd80e94b2cd28
--- /dev/null
+++ b/test/IDE/signature_help_init.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=INIT -source-filename=%s | %FileCheck %s --check-prefix=INIT
+
+struct Person {
+  init(name: String, age: Int, profession job: String) { }
+}
+
+Person(name: "John", age: #^INIT^#)
+// INIT:     Begin signatures, 1 items
+// INIT-DAG: Signature[Active]: init(<param name="name">name: String</param>, <param name="age" active>age: Int</param>, <param name="job">profession: String</param>)
diff --git a/test/IDE/signature_help_member_closure.swift b/test/IDE/signature_help_member_closure.swift
new file mode 100644
index 0000000000000..8e175a29f5066
--- /dev/null
+++ b/test/IDE/signature_help_member_closure.swift
@@ -0,0 +1,11 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=MEMBER_CLOSURE -source-filename=%s | %FileCheck %s --check-prefix=MEMBER_CLOSURE
+
+struct Observable {
+  var observer: (String, Int?, [AnyHashable: [Double?]]) async throws -> [Observable?]
+  
+  func notify() async throws {
+    _ = try await observer("EVENT", #^MEMBER_CLOSURE^#, [:])
+    // MEMBER_CLOSURE:     Begin signatures, 1 items
+    // MEMBER_CLOSURE-DAG: Signature[Active]: observer(<param>String</param>, <param active>Int?</param>, <param>[AnyHashable : [Double?]]</param>) async throws -> [Observable?]
+  }
+}
diff --git a/test/IDE/signature_help_member_func.swift b/test/IDE/signature_help_member_func.swift
new file mode 100644
index 0000000000000..46cd62dedb8ee
--- /dev/null
+++ b/test/IDE/signature_help_member_func.swift
@@ -0,0 +1,47 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=MEMBER_FUNC -source-filename=%s | %FileCheck %s --check-prefix=MEMBER_FUNC
+
+struct Adder {
+  func add(_ x: Int, to y: Int) -> Int {
+    return x + y
+  }
+  
+  func add(oneTo x: inout Int) {
+    x += 1
+  }
+  
+  func add<T: AdditiveArithmetic>(_ x: T, to y: T) -> T {
+    return x + y
+  }
+  
+  func add(first: Double!, second: Float, third: Int) -> Double {
+    return first + Double(second) + Double(third)
+  }
+  
+  func add(arg1 param1: Double, arg2: Float, arg3 param3: Int) -> Double {
+    return param1 + Double(arg2) + Double(param3)
+  }
+  
+  func add(numbers: Double...) -> Double {
+    return numbers.reduce(into: 0) { $0 += $1 }
+  }
+  
+  func add(x: Int, y: Int, with adder: (Int, Int) -> Int) -> Int {
+    return adder(x, y)
+  }
+  
+  func add(x: Int) -> (Int) -> Int {
+    return { (y: Int) in x + y }
+  }
+}
+
+let adder = Adder()
+adder.add(#^MEMBER_FUNC^#)
+// MEMBER_FUNC:     Begin signatures, 8 items
+// MEMBER_FUNC-DAG: Signature[Active]: add(<param name="x" active>_ x: Int</param>, <param name="y">to: Int</param>) -> Int
+// MEMBER_FUNC-DAG: Signature: add(<param name="x" active>oneTo: inout Int</param>)
+// MEMBER_FUNC-DAG: Signature: add(<param name="x" active>_ x: AdditiveArithmetic</param>, <param name="y">to: AdditiveArithmetic</param>) -> AdditiveArithmetic
+// MEMBER_FUNC-DAG: Signature: add(<param name="first" active>first: Double!</param>, <param name="second">second: Float</param>, <param name="third">third: Int</param>) -> Double
+// MEMBER_FUNC-DAG: Signature: add(<param name="param1" active>arg1: Double</param>, <param name="arg2">arg2: Float</param>, <param name="param3">arg3: Int</param>) -> Double
+// MEMBER_FUNC-DAG: Signature: add(<param name="numbers" active>numbers: Double...</param>) -> Double
+// MEMBER_FUNC-DAG: Signature: add(<param name="x" active>x: Int</param>, <param name="y">y: Int</param>, <param name="adder">with: (Int, Int) -> Int</param>) -> Int
+// MEMBER_FUNC-DAG: Signature: add(<param name="x" active>x: Int</param>) -> (Int) -> Int
diff --git a/test/IDE/signature_help_member_generic.swift b/test/IDE/signature_help_member_generic.swift
new file mode 100644
index 0000000000000..291dfa59a4c9e
--- /dev/null
+++ b/test/IDE/signature_help_member_generic.swift
@@ -0,0 +1,12 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=MEMBER_GENERIC -source-filename=%s | %FileCheck %s --check-prefix=MEMBER_GENERIC
+
+struct Vector<Value> {
+  init(elements: [Value]) { }
+  
+  func dot(with other: Vector<Value>) -> Value { fatalError() }
+}
+
+let vec = Vector(elements: [1.0, 2.1, 3.4])
+vec.dot(with: #^MEMBER_GENERIC^#)
+// MEMBER_GENERIC:     Begin signatures, 1 items
+// MEMBER_GENERIC-DAG: Signature[Active]: dot(<param name="other" active>with: Vector<Double></param>) -> Double
diff --git a/test/IDE/signature_help_member_subscript.swift b/test/IDE/signature_help_member_subscript.swift
new file mode 100644
index 0000000000000..3dca0ddb1dc03
--- /dev/null
+++ b/test/IDE/signature_help_member_subscript.swift
@@ -0,0 +1,23 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=MEMBER_SUBSCRIPT -source-filename=%s | %FileCheck %s --check-prefix=MEMBER_SUBSCRIPT
+
+struct Matrix {
+  subscript(row: Int, column: Int) -> Int {
+    return 0
+  }
+  
+  subscript(row r: Int) -> [Int] {
+    return []
+  }
+  
+  subscript(column c: Int) -> [Int] {
+    return []
+  }
+}
+
+let matrix = Matrix()
+matrix[#^MEMBER_SUBSCRIPT^#]
+// MEMBER_SUBSCRIPT:     Begin signatures, 4 items
+// MEMBER_SUBSCRIPT-DAG: Signature[Active]: subscript(<param active>keyPath: KeyPath<Matrix, Value></param>) -> Value
+// MEMBER_SUBSCRIPT-DAG: Signature: subscript(<param name="row" active>row: Int</param>, <param name="column">column: Int</param>) -> Int
+// MEMBER_SUBSCRIPT-DAG: Signature: subscript(<param name="r" active>row: Int</param>) -> [Int]
+// MEMBER_SUBSCRIPT-DAG: Signature: subscript(<param name="c" active>column: Int</param>) -> [Int]
diff --git a/test/IDE/signature_help_raw_identifier.swift b/test/IDE/signature_help_raw_identifier.swift
new file mode 100644
index 0000000000000..72c00378a95f3
--- /dev/null
+++ b/test/IDE/signature_help_raw_identifier.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=RAW_ID -source-filename=%s | %FileCheck %s --check-prefix=RAW_ID
+
+struct `Raw Identifier` {
+  func `some method :)`(`argument label!` `param label?`: Int) {}
+}
+
+`Raw Identifier`().`some method :)`(#^RAW_ID^#)
+// RAW_ID:     Begin signatures, 1 items
+// RAW_ID-DAG: Signature[Active]: `some method :)`(<param name="param label?" active>`argument label!`: Int</param>)
diff --git a/test/IDE/signature_help_top_level.swift b/test/IDE/signature_help_top_level.swift
new file mode 100644
index 0000000000000..f5e0bdb787c8d
--- /dev/null
+++ b/test/IDE/signature_help_top_level.swift
@@ -0,0 +1,44 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=TOP_LEVEL -source-filename=%s | %FileCheck %s --check-prefix=TOP_LEVEL
+
+func add(_ x: Int, to y: Int) -> Int {
+  return x + y
+}
+
+func add(oneTo x: inout Int) {
+  x += 1
+}
+
+func add<T: AdditiveArithmetic>(_ x: T, to y: T) -> T {
+  return x + y
+}
+
+func add(first: Double!, second: Float, third: Int) -> Double {
+  return first + Double(second) + Double(third)
+}
+
+func add(arg1 param1: Double, arg2: Float, arg3 param3: Int) -> Double {
+  return param1 + Double(arg2) + Double(param3)
+}
+
+func add(numbers: Double...) -> Double {
+  return numbers.reduce(into: 0) { $0 += $1 }
+}
+
+func add(x: Int, y: Int, with adder: (Int, Int) -> Int) -> Int {
+  return adder(x, y)
+}
+
+func add(x: Int) -> (Int) -> Int {
+  return { (y: Int) in x + y }
+}
+
+add(#^TOP_LEVEL^#)
+// TOP_LEVEL:     Begin signatures, 8 items
+// TOP_LEVEL-DAG: Signature[Active]: add(<param name="x" active>_ x: Int</param>, <param name="y">to: Int</param>) -> Int
+// TOP_LEVEL-DAG: Signature: add(<param name="x" active>oneTo: inout Int</param>)
+// TOP_LEVEL-DAG: Signature: add(<param name="x" active>_ x: AdditiveArithmetic</param>, <param name="y">to: AdditiveArithmetic</param>) -> AdditiveArithmetic
+// TOP_LEVEL-DAG: Signature: add(<param name="first" active>first: Double!</param>, <param name="second">second: Float</param>, <param name="third">third: Int</param>) -> Double
+// TOP_LEVEL-DAG: Signature: add(<param name="param1" active>arg1: Double</param>, <param name="arg2">arg2: Float</param>, <param name="param3">arg3: Int</param>) -> Double
+// TOP_LEVEL-DAG: Signature: add(<param name="numbers" active>numbers: Double...</param>) -> Double
+// TOP_LEVEL-DAG: Signature: add(<param name="x" active>x: Int</param>, <param name="y">y: Int</param>, <param name="adder">with: (Int, Int) -> Int</param>) -> Int
+// TOP_LEVEL-DAG: Signature: add(<param name="x" active>x: Int</param>) -> (Int) -> Int
diff --git a/test/IDE/signature_help_top_level_generic.swift b/test/IDE/signature_help_top_level_generic.swift
new file mode 100644
index 0000000000000..af9640d898d3f
--- /dev/null
+++ b/test/IDE/signature_help_top_level_generic.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=TOP_LEVEL_GENERIC -source-filename=%s | %FileCheck %s --check-prefix=TOP_LEVEL_GENERIC
+
+func add<T>(x: T, y: T, with adder: (T, T) -> T) -> T where T: AdditiveArithmetic {
+  return adder(x, y)
+}
+
+add(x: "A", y: "B", with: #^TOP_LEVEL_GENERIC^#)
+// TOP_LEVEL_GENERIC:     Begin signatures, 1 items
+// TOP_LEVEL_GENERIC-DAG: Signature[Active]: add(<param name="x">x: String</param>, <param name="y">y: String</param>, <param name="adder" active>with: (String, String) -> String</param>) -> String
diff --git a/test/IRGen/CoroutineAccessorsDebugLoc.swift b/test/IRGen/CoroutineAccessorsDebugLoc.swift
new file mode 100644
index 0000000000000..7cfeb50be1547
--- /dev/null
+++ b/test/IRGen/CoroutineAccessorsDebugLoc.swift
@@ -0,0 +1,19 @@
+// REQUIRES: swift_feature_CoroutineAccessors
+// RUN: %target-swift-frontend %s -g -c -O -o - -emit-irgen -enable-experimental-feature CoroutineAccessors | %FileCheck %s
+
+// This test checks to made sure that the ReadAccessor s26CoroutineAccessorsDebugLoc1SV3irmSivr that has a call to @llvm.coro.id.retcon.once, also has a debug location set.
+
+// CHECK-LABEL: @"$s26CoroutineAccessorsDebugLoc1SV3irmSivr"
+// CHECK: %{{.*}} = call token ({{.*}}) @llvm.coro.id.retcon.once({{.*}}), !dbg ![[DBGLOC:[0-9]+]]
+// CHECK-NEXT: %{{.*}} = call ptr @llvm.coro.begin({{.*}}), !dbg ![[DBGLOC]]
+
+public struct S {
+public var o: any AnyObject
+public var _i: Int = 0
+
+public var irm: Int {
+  _read {
+    yield _i
+  }
+} // public var irm
+}
diff --git a/test/IRGen/Inputs/AvailabilityDomains.h b/test/IRGen/Inputs/AvailabilityDomains.h
new file mode 100644
index 0000000000000..ad923bc48a39b
--- /dev/null
+++ b/test/IRGen/Inputs/AvailabilityDomains.h
@@ -0,0 +1,28 @@
+#include <availability_domain.h>
+
+int dynamic_domain_pred();
+
+CLANG_ENABLED_AVAILABILITY_DOMAIN(EnabledDomain);
+CLANG_DISABLED_AVAILABILITY_DOMAIN(DisabledDomain);
+CLANG_DYNAMIC_AVAILABILITY_DOMAIN(DynamicDomain, dynamic_domain_pred);
+
+#define AVAIL 0
+#define UNAVAIL 1
+
+__attribute__((availability(domain : EnabledDomain, AVAIL))) void
+available_in_enabled_domain(void);
+
+__attribute__((availability(domain : EnabledDomain, UNAVAIL))) void
+unavailable_in_enabled_domain(void);
+
+__attribute__((availability(domain : DisabledDomain, AVAIL))) void
+available_in_disabled_domain(void);
+
+__attribute__((availability(domain : DisabledDomain, UNAVAIL))) void
+unavailable_in_disabled_domain(void);
+
+__attribute__((availability(domain : DynamicDomain, AVAIL))) void
+available_in_dynamic_domain(void);
+
+__attribute__((availability(domain : DynamicDomain, UNAVAIL))) void
+unavailable_in_dynamic_domain(void);
diff --git a/test/IRGen/Inputs/associated_type_by_mangled_name.swift b/test/IRGen/Inputs/associated_type_by_mangled_name.swift
new file mode 100644
index 0000000000000..3e8ee23c00200
--- /dev/null
+++ b/test/IRGen/Inputs/associated_type_by_mangled_name.swift
@@ -0,0 +1,21 @@
+public protocol Proto {
+    associatedtype T: Proto
+
+    var value: T {get}
+}
+
+public func makeThing<P: Proto>(_ t: P) -> some Proto {
+    return ProtoImpl(t.value)
+}
+
+public struct ProtoImpl<V>: Proto {
+    public let genValue: V
+
+    public init(_ genValue: V) {
+        self.genValue = genValue
+    }
+
+    public var value: some Proto {
+        return self
+    }
+}
diff --git a/test/IRGen/Inputs/objc_implementation.h b/test/IRGen/Inputs/objc_implementation.h
index 1f27633f7e8fd..ff8a2071de764 100644
--- a/test/IRGen/Inputs/objc_implementation.h
+++ b/test/IRGen/Inputs/objc_implementation.h
@@ -1,3 +1,4 @@
+#if __OBJC__
 #import <Foundation/Foundation.h>
 
 @interface ImplClass: NSObject <NSCopying>
@@ -31,11 +32,13 @@
 - (void)category2Method:(int)param;
 
 @end
+#endif
 
 extern void implFunc(int param);
 extern void implFuncCName(int param) __asm__("_implFuncAsmName");
+extern void implFuncRenamed_C(int param) __attribute__((swift_name("implFuncRenamed_Swift(param:)")));
 
-
+#if __OBJC__
 @interface NoImplClass
 
 - (void)noImplMethod:(int)param;
@@ -57,3 +60,4 @@ extern void implFuncCName(int param) __asm__("_implFuncAsmName");
 @property (assign) int afterInt;
 
 @end
+#endif
diff --git a/test/IRGen/abi_v7k.swift b/test/IRGen/abi_v7k.swift
index cec49c0801a88..864cc5887c258 100644
--- a/test/IRGen/abi_v7k.swift
+++ b/test/IRGen/abi_v7k.swift
@@ -98,7 +98,7 @@ func testData(x: DataCase) -> Double {
 // CHECK: [[ID:%[0-9]+]] = phi i32 [ 2, {{.*}} ], [ 1, {{.*}} ]
 // CHECK: ret i32 [[ID]]
 // V7K-LABEL: _$s8test_v7k0A6Clike2
-// V7K: tst.w r0, #1
+// V7K: cmp r0, #1
 // V7K: movs r0, #1
 // V7K: movs r0, #2
 enum CLike2 {
@@ -155,7 +155,8 @@ func testClike8(t: Int, x: CLike8) -> Int {
 // CHECK: bitcast i64 [[RESULT]] to double
 // CHECK: phi double [ 0.000000e+00, {{.*}} ]
 // V7K-LABEL: _$s8test_v7k0A7SingleP
-// V7K: tst.w     r2, #1
+// V7K: sxtb [[R0:r[0-9]+]], r2
+// V7K: cmp [[R0]], #1
 // V7K: vldr    d0, [{{.*}}]
 enum SinglePayload {
   case Paragraph
@@ -212,13 +213,14 @@ func testMultiP(x: MultiPayload) -> Double {
 
 // CHECK-LABEL: define hidden swiftcc float @"$s8test_v7k0A3Opt{{.*}}"(i32 %0, i8 %1)
 // CHECK: entry:
-// CHECK: [[TR:%.*]] = trunc i8 %1
+// CHECK: [[TR:%.*]] = icmp eq i8 %1, 1
 // CHECK: br i1 [[TR]], {{.*}}, label %[[PAYLOADLABEL:.*]]
 // CHECK: [[PAYLOADLABEL]]:
 // CHECK: [[ID:%[0-9]+]] = bitcast i32 %0 to float
 // CHECK: ret float
 // V7K-LABEL: _$s8test_v7k0A3Opt
-// V7K:         tst.w     r1, #1
+// V7K:         sxtb    [[R0:r[0-9]+]], r1
+// V7K:         cmp     [[R0]], #1
 // V7K:         vmov    s0, r0
 // V7K:         vstr    s0, [sp, [[SLOT:#[0-9]+]]
 // V7K:         vldr    s0, [sp, [[SLOT]]
@@ -296,7 +298,7 @@ func testRet3() -> MyRect2 {
 }
 
 // Returning tuple?: (Int x 6)?
-// CHECK-LABEL: define hidden swiftcc void @"$s8test_v7k7minMax2{{.*}}"(ptr noalias nocapture sret({{.*}}) %0, i32 %1, i32 %2)
+// CHECK-LABEL: define hidden swiftcc void @"$s8test_v7k7minMax2{{.*}}"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, i32 %1, i32 %2)
 // V7K-LABEL: _$s8test_v7k7minMax2
 // We will indirectly return an optional with the address in r0, input parameters will be in r1 and r2
 // V7K: str r0, [sp, [[IDX:#[0-9]+]]]
@@ -308,7 +310,6 @@ func testRet3() -> MyRect2 {
 // V7K: str.w {{.*}}, [{{.*}}[[R0_RELOAD]], #12]
 // V7K: str {{.*}}, [{{.*}}[[R0_RELOAD]], #16]
 // V7K: str {{.*}}, [{{.*}}[[R0_RELOAD]], #20]
-// V7K: and {{.*}}, {{.*}}, #1
 // V7K: strb {{.*}}, [{{.*}}[[R0_RELOAD]], #24]
 func minMax2(x : Int, y : Int) -> (min: Int, max: Int, min2: Int, max2: Int, min3: Int, max3: Int)? {
     if x == y {
@@ -324,7 +325,7 @@ func minMax2(x : Int, y : Int) -> (min: Int, max: Int, min2: Int, max2: Int, min
 }
 
 // Returning struct?: {Int x 6}?
-// CHECK-LABEL: define hidden swiftcc void @"$s8test_v7k7minMax3{{.*}}"(ptr noalias nocapture sret({{.*}}) %0, i32 %1, i32 %2)
+// CHECK-LABEL: define hidden swiftcc void @"$s8test_v7k7minMax3{{.*}}"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, i32 %1, i32 %2)
 // V7K-LABEL: _$s8test_v7k7minMax3
 struct Ret {
   var min:Int
diff --git a/test/IRGen/abitypes_arm.swift b/test/IRGen/abitypes_arm.swift
index 9428294483d9c..52bd8b101457d 100644
--- a/test/IRGen/abitypes_arm.swift
+++ b/test/IRGen/abitypes_arm.swift
@@ -11,6 +11,6 @@ class Foo {
   }
 }
 
-// armv7: define internal void @makeOne(ptr noalias sret({{.*}}) align 4 %agg.result, float{{( noundef)?}} %f, float{{( noundef)?}} %s)
+// armv7: define internal void @makeOne(ptr{{( dead_on_unwind)?}} noalias{{( writable)?}} sret({{.*}}) align 4 %agg.result, float{{( noundef)?}} %f, float{{( noundef)?}} %s)
 // armv7s: define internal void @makeOne(ptr noalias sret({{.*}}) align 4 %agg.result, float %f, float %s)
 // armv7k: define internal %struct.One @makeOne(float {{.*}}%f, float {{.*}}%s)
diff --git a/test/IRGen/abitypes_objc.swift b/test/IRGen/abitypes_objc.swift
index 3bf060dd3a650..648e46c5201c2 100644
--- a/test/IRGen/abitypes_objc.swift
+++ b/test/IRGen/abitypes_objc.swift
@@ -27,20 +27,20 @@ class Foo {
   // x86_64-macosx: define internal { <2 x float>, <2 x float> } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr %0, ptr %1) {{[#0-9]*}} {
   // x86_64-ios: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr swiftself %0) {{.*}} {
   // x86_64-ios: define internal { <2 x float>, <2 x float> } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr %0, ptr %1) {{[#0-9]*}} {
-  // i386-ios: define hidden swiftcc void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr noalias nocapture sret({{.*}}) %0, ptr swiftself %1) {{.*}} {
-  // i386-ios: define internal void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2) {{[#0-9]*}} {
+  // i386-ios: define hidden swiftcc void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr swiftself %1) {{.*}} {
+  // i386-ios: define internal void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2) {{[#0-9]*}} {
   // armv7-ios: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr swiftself %0) {{.*}} {
-  // armv7-ios: define internal void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2) {{[#0-9]*}} {
+  // armv7-ios: define internal void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2) {{[#0-9]*}} {
   // armv7s-ios: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr swiftself %0) {{.*}} {
-  // armv7s-ios: define internal void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2) {{[#0-9]*}} {
+  // armv7s-ios: define internal void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2) {{[#0-9]*}} {
   // arm64-ios: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr swiftself %0) {{.*}} {
   // arm64-ios: define internal [[ARM64_MYRECT]] @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr %0, ptr %1) {{[#0-9]*}} {
   // x86_64-tvos: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr swiftself %0) {{.*}} {
   // x86_64-tvos: define internal { <2 x float>, <2 x float> } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr %0, ptr %1) {{[#0-9]*}} {
   // arm64-tvos: define hidden swiftcc { float, float, float, float }  @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr swiftself %0) {{.*}} {
   // arm64-tvos: define internal [[ARM64_MYRECT]] @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr %0, ptr %1) {{[#0-9]*}} {
-  // i386-watchos: define hidden swiftcc void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr noalias nocapture sret({{.*}}) %0, ptr swiftself %1) {{.*}} {
-  // i386-watchos: define internal void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2) {{[#0-9]*}} {
+  // i386-watchos: define hidden swiftcc void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr swiftself %1) {{.*}} {
+  // i386-watchos: define internal void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2) {{[#0-9]*}} {
   // armv7k-watchos: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr swiftself %0) {{.*}} {
   // armv7k-watchos: define internal [[ARMV7K_MYRECT]] @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(ptr %0, ptr %1) {{[#0-9]*}} {
   // armv64_32-watchos: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(ptr swiftself %0) {{.*}} {
@@ -87,9 +87,9 @@ class Foo {
   // x86_64-macosx: define hidden swiftcc float @"$s8abitypes3FooC17getXFromRectSwift{{.*}}"(float %0, float %1, float %2, float %3, ptr swiftself %4) {{.*}} {
   // x86_64-macosx: [[COERCED:%.*]] = alloca [[MYRECT:%.*MyRect.*]], align 8
   // x86_64-macosx: [[SEL:%.*]] = load ptr, ptr @"\01L_selector(getXFromRect:)", align 8
-  // x86_64-macosx: [[T0:%.*]] = getelementptr inbounds { <2 x float>, <2 x float> }, ptr [[COERCED]], i32 0, i32 0
+  // x86_64-macosx: [[T0:%.*]] = getelementptr inbounds{{.*}} { <2 x float>, <2 x float> }, ptr [[COERCED]], i32 0, i32 0
   // x86_64-macosx: [[FIRST_HALF:%.*]] = load <2 x float>, ptr [[T0]]
-  // x86_64-macosx: [[T0:%.*]] = getelementptr inbounds { <2 x float>, <2 x float> }, ptr [[COERCED]], i32 0, i32 1
+  // x86_64-macosx: [[T0:%.*]] = getelementptr inbounds{{.*}} { <2 x float>, <2 x float> }, ptr [[COERCED]], i32 0, i32 1
   // x86_64-macosx: [[SECOND_HALF:%.*]] = load <2 x float>, ptr [[T0]]
   // x86_64-macosx: [[RESULT:%.*]] = call float @objc_msgSend(ptr %4, ptr [[SEL]], <2 x float> [[FIRST_HALF]], <2 x float> [[SECOND_HALF]])
   // armv7-ios: define hidden swiftcc float @"$s8abitypes3FooC17getXFromRectSwift{{[_0-9a-zA-Z]*}}F"(float %0, float %1, float %2, float %3, ptr swiftself %4) {{.*}} {
@@ -157,7 +157,7 @@ class Foo {
   // armv7-ios: define hidden swiftcc float @"$s8abitypes3FooC4barc{{[_0-9a-zA-Z]*}}F"(ptr %0, ptr swiftself %1) {{.*}} {
   // armv7-ios: [[RESULT:%.*]] = alloca [[RECTTYPE:%.*MyRect.*]], align 4
   // armv7-ios: load ptr, ptr @"\01L_selector(newRect)", align 4
-  // armv7-ios: call void @objc_msgSend_stret(ptr noalias nocapture sret({{.*}}) %call.aggresult
+  // armv7-ios: call void @objc_msgSend_stret(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %call.aggresult
   // armv7-ios: [[GEP1:%.*]] = getelementptr inbounds [[RECTTYPE]], ptr [[RESULT]], i32 0, i32 1
   // armv7-ios: [[GEP2:%.*]] = getelementptr inbounds {{.*}}, ptr [[GEP1]], i32 0, i32 0
   // armv7-ios: [[RETVAL:%.*]] = load float, ptr [[GEP2]], align 4
@@ -167,7 +167,7 @@ class Foo {
   // armv7s-ios: define hidden swiftcc float @"$s8abitypes3FooC4barc{{[_0-9a-zA-Z]*}}F"(ptr %0, ptr swiftself %1) {{.*}} {
   // armv7s-ios: [[RESULT:%.*]] = alloca [[RECTTYPE:%.*MyRect.*]], align 4
   // armv7s-ios: load ptr, ptr @"\01L_selector(newRect)", align 4
-  // armv7s-ios: call void @objc_msgSend_stret(ptr noalias nocapture sret({{.*}}) %call.aggresult
+  // armv7s-ios: call void @objc_msgSend_stret(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %call.aggresult
   // armv7s-ios: [[GEP1:%.*]] = getelementptr inbounds [[RECTTYPE]], ptr [[RESULT]], i32 0, i32 1
   // armv7s-ios: [[GEP2:%.*]] = getelementptr inbounds {{.*}}, ptr [[GEP1]], i32 0, i32 0
   // armv7s-ios: [[RETVAL:%.*]] = load float, ptr [[GEP2]], align 4
@@ -185,7 +185,7 @@ class Foo {
   }
 
   // x86_64-macosx: define hidden swiftcc { double, double, double } @"$s8abitypes3FooC3baz{{[_0-9a-zA-Z]*}}F"(ptr swiftself %0) {{.*}} {
-  // x86_64-macosx: define internal void @"$s8abitypes3FooC3baz{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2) {{[#0-9]*}} {
+  // x86_64-macosx: define internal void @"$s8abitypes3FooC3baz{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2) {{[#0-9]*}} {
   @objc dynamic func baz() -> Trio {
     return Trio(i: 1.0, j: 2.0, k: 3.0)
   }
@@ -199,9 +199,9 @@ class Foo {
 
   // x86_64-macosx:      define hidden swiftcc i64 @"$s8abitypes3FooC7getpair{{[_0-9a-zA-Z]*}}F"(ptr %0, ptr swiftself %1) {{.*}} {
   // x86_64-macosx:      [[RESULT:%.*]] = call i64 @objc_msgSend
-  // x86_64-macosx:      [[GEP1:%.*]] = getelementptr inbounds { i64 }, ptr {{.*}}, i32 0, i32 0
+  // x86_64-macosx:      [[GEP1:%.*]] = getelementptr inbounds{{.*}} { i64 }, ptr {{.*}}, i32 0, i32 0
   // x86_64-macosx:      store i64 [[RESULT]], ptr [[GEP1]]
-  // x86_64-macosx:      [[GEP2:%.*]] = getelementptr inbounds { i64 }, ptr {{.*}}, i32 0, i32 0
+  // x86_64-macosx:      [[GEP2:%.*]] = getelementptr inbounds{{.*}} { i64 }, ptr {{.*}}, i32 0, i32 0
   // x86_64-macosx:      load i64, ptr [[GEP2]]
   // x86_64-macosx:      ret i64
   func getpair(_ p: StructReturns) -> IntPair {
@@ -218,7 +218,7 @@ class Foo {
   // x86_64-macosx:      call void @llvm.lifetime.start
   // x86_64-macosx:      store i32 {{.*}}
   // x86_64-macosx:      store i32 {{.*}}
-  // x86_64-macosx:      [[T0:%.*]] = getelementptr inbounds { i64 }, ptr
+  // x86_64-macosx:      [[T0:%.*]] = getelementptr inbounds{{.*}} { i64 }, ptr
   // x86_64-macosx:      load i64, ptr [[T0]], align 8
   // x86_64-macosx:      call void @llvm.lifetime.end
   // x86_64-macosx:      ret i64
@@ -480,17 +480,17 @@ class Foo {
     return g.invert(b)
   }
 
-  // x86_64-macosx: define hidden swiftcc void @"$s8abitypes3FooC10throwsTestyySbKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2) {{.*}} {
+  // x86_64-macosx: define hidden swiftcc void @"$s8abitypes3FooC10throwsTestyySbKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2) {{.*}} {
   // x86_64-macosx: [[SEL:%[0-9]+]] = load ptr, ptr @"\01L_selector(negateThrowing:error:)", align 8
   // x86_64-macosx: call signext i8 @objc_msgSend(ptr {{%[0-9]+}}, ptr [[SEL]], i8 signext {{%[0-9]+}}, ptr {{%[0-9]+}})
   // x86_64-macosx: }
 
-  // x86_64-ios: define hidden swiftcc void @"$s8abitypes3FooC10throwsTestyySbKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2) {{.*}} {
+  // x86_64-ios: define hidden swiftcc void @"$s8abitypes3FooC10throwsTestyySbKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2) {{.*}} {
   // x86_64-ios: [[SEL:%[0-9]+]] = load ptr, ptr @"\01L_selector(negateThrowing:error:)", align 8
   // x86_64-ios: call zeroext i1 @objc_msgSend(ptr {{%[0-9]+}}, ptr [[SEL]], i1 zeroext {{%[0-9]+}}, ptr {{%[0-9]+}})
   // x86_64-ios: }
 
-  // i386-ios: define hidden swiftcc void @"$s8abitypes3FooC10throwsTestyySbKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture dereferenceable(4) %2) {{.*}} {
+  // i386-ios: define hidden swiftcc void @"$s8abitypes3FooC10throwsTestyySbKF"(i1 %0, ptr swiftself %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(4) %2) {{.*}} {
   // i386-ios: [[SEL:%[0-9]+]] = load ptr, ptr @"\01L_selector(negateThrowing:error:)", align 4
   // i386-ios: call signext i8 @objc_msgSend(ptr {{%[0-9]+}}, ptr [[SEL]], i8 signext {{%[0-9]+}}, ptr {{%[0-9]+}})
   // i386-ios: }
@@ -547,18 +547,18 @@ class Foo {
   }
 
   // arm64-ios: define hidden swiftcc { i64, i64, i64, i64 } @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}F"(ptr %0, i64 %1, i64 %2, i64 %3, i64 %4, ptr swiftself %5) {{.*}} {
-  // arm64-ios: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2, ptr %3, ptr %4) {{[#0-9]*}} {
+  // arm64-ios: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2, ptr %3, ptr %4) {{[#0-9]*}} {
   //
   // arm64e-ios: define hidden swiftcc { i64, i64, i64, i64 } @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}F"(ptr %0, i64 %1, i64 %2, i64 %3, i64 %4, ptr swiftself %5) {{.*}} {
-  // arm64e-ios: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2, ptr %3, ptr %4) {{.*}} {
+  // arm64e-ios: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2, ptr %3, ptr %4) {{.*}} {
   //
   // arm64-tvos: define hidden swiftcc { i64, i64, i64, i64 } @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}F"(ptr %0, i64 %1, i64 %2, i64 %3, i64 %4, ptr swiftself %5) {{.*}} {
-  // arm64-tvos: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2, ptr %3, ptr %4) {{[#0-9]*}} {
+  // arm64-tvos: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2, ptr %3, ptr %4) {{[#0-9]*}} {
   // arm64-macosx: define hidden swiftcc { i64, i64, i64, i64 } @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}F"(ptr %0, i64 %1, i64 %2, i64 %3, i64 %4, ptr swiftself %5) {{.*}} {
-  // arm64-macosx: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2, ptr %3, ptr %4) {{.*}} {
+  // arm64-macosx: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2, ptr %3, ptr %4) {{.*}} {
   //
   // arm64-watchos: define hidden swiftcc { i64, i64, i64, i64 } @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}F"(ptr %0, i64 %1, i64 %2, i64 %3, i64 %4, ptr swiftself %5) {{.*}} {
-  // arm64-watchos: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2, ptr %3, ptr %4) {{[#0-9]*}} {
+  // arm64-watchos: define internal void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2, ptr %3, ptr %4) {{[#0-9]*}} {
   @objc dynamic func callJustReturn(_ r: StructReturns, with v: BigStruct) -> BigStruct {
     return r.justReturn(v)
   }
@@ -567,35 +567,35 @@ class Foo {
 // We need to allocate enough memory on the stack to hold the argument value we load.
 // arm64-ios: define swiftcc void @"$s8abitypes14testBOOLStructyyF"()
 // arm64-ios:  [[COERCED:%.*]] = alloca i64
-// arm64-ios:  [[PTR0:%.*]] = getelementptr inbounds %TSo14FiveByteStructV, ptr [[COERCED]], {{i.*}} 0, {{i.*}} 0
-// arm64-ios:  [[PTR1:%.*]] = getelementptr inbounds %T10ObjectiveC8ObjCBoolV, ptr [[PTR0]], {{i.*}} 0, {{i.*}} 0
-// arm64-ios:  [[PTR2:%.*]] = getelementptr inbounds %TSb, ptr [[PTR1]], {{i.*}} 0, {{i.*}} 0
+// arm64-ios:  [[PTR0:%.*]] = getelementptr inbounds{{.*}} %TSo14FiveByteStructV, ptr [[COERCED]], {{i.*}} 0, {{i.*}} 0
+// arm64-ios:  [[PTR1:%.*]] = getelementptr inbounds{{.*}} %T10ObjectiveC8ObjCBoolV, ptr [[PTR0]], {{i.*}} 0, {{i.*}} 0
+// arm64-ios:  [[PTR2:%.*]] = getelementptr inbounds{{.*}} %TSb, ptr [[PTR1]], {{i.*}} 0, {{i.*}} 0
 // arm64-ios:  store i8 0, ptr [[PTR2]], align 8
 // arm64-ios:  [[ARG:%.*]] = load i64, ptr [[COERCED]]
 // arm64-ios:  call void @objc_msgSend(ptr {{.*}}, ptr {{.*}}, i64 [[ARG]])
 //
 // arm64e-ios: define swiftcc void @"$s8abitypes14testBOOLStructyyF"()
 // arm64e-ios:  [[COERCED:%.*]] = alloca i64
-// arm64e-ios:  [[PTR0:%.*]] = getelementptr inbounds %TSo14FiveByteStructV, ptr [[COERCED]], {{i.*}} 0, {{i.*}} 0
-// arm64e-ios:  [[PTR1:%.*]] = getelementptr inbounds %T10ObjectiveC8ObjCBoolV, ptr [[PTR0]], {{i.*}} 0, {{i.*}} 0
-// arm64e-ios:  [[PTR2:%.*]] = getelementptr inbounds %TSb, ptr [[PTR1]], {{i.*}} 0, {{i.*}} 0
+// arm64e-ios:  [[PTR0:%.*]] = getelementptr inbounds{{.*}} %TSo14FiveByteStructV, ptr [[COERCED]], {{i.*}} 0, {{i.*}} 0
+// arm64e-ios:  [[PTR1:%.*]] = getelementptr inbounds{{.*}} %T10ObjectiveC8ObjCBoolV, ptr [[PTR0]], {{i.*}} 0, {{i.*}} 0
+// arm64e-ios:  [[PTR2:%.*]] = getelementptr inbounds{{.*}} %TSb, ptr [[PTR1]], {{i.*}} 0, {{i.*}} 0
 // arm64e-ios:  store i8 0, ptr [[PTR2]], align 8
 // arm64e-ios:  [[ARG:%.*]] = load i64, ptr [[COERCED]]
 // arm64e-ios:  call void @objc_msgSend(ptr {{.*}}, ptr {{.*}}, i64 [[ARG]])
 // arm64-macosx: define swiftcc void @"$s8abitypes14testBOOLStructyyF"()
 // arm64-macosx:  [[COERCED:%.*]] = alloca i64
-// arm64-macosx:  [[PTR0:%.*]] = getelementptr inbounds %TSo14FiveByteStructV, ptr [[COERCED]], {{i.*}} 0, {{i.*}} 0
-// arm64-macosx:  [[PTR1:%.*]] = getelementptr inbounds %T10ObjectiveC8ObjCBoolV, ptr [[PTR0]], {{i.*}} 0, {{i.*}} 0
-// arm64-macosx:  [[PTR2:%.*]] = getelementptr inbounds %TSb, ptr [[PTR1]], {{i.*}} 0, {{i.*}} 0
+// arm64-macosx:  [[PTR0:%.*]] = getelementptr inbounds{{.*}} %TSo14FiveByteStructV, ptr [[COERCED]], {{i.*}} 0, {{i.*}} 0
+// arm64-macosx:  [[PTR1:%.*]] = getelementptr inbounds{{.*}} %T10ObjectiveC8ObjCBoolV, ptr [[PTR0]], {{i.*}} 0, {{i.*}} 0
+// arm64-macosx:  [[PTR2:%.*]] = getelementptr inbounds{{.*}} %TSb, ptr [[PTR1]], {{i.*}} 0, {{i.*}} 0
 // arm64-macosx:  store i8 0, ptr [[PTR2]], align 8
 // arm64-macosx:  [[ARG:%.*]] = load i64, ptr [[COERCED]]
 // arm64-macosx:  call void @objc_msgSend(ptr {{.*}}, ptr {{.*}}, i64 [[ARG]])
 //
 // arm64-watchos: define swiftcc void @"$s8abitypes14testBOOLStructyyF"()
 // arm64-watchos:  [[COERCED:%.*]] = alloca i64
-// arm64-watchos:  [[PTR0:%.*]] = getelementptr inbounds %TSo14FiveByteStructV, ptr [[COERCED]], {{i.*}} 0, {{i.*}} 0
-// arm64-watchos:  [[PTR1:%.*]] = getelementptr inbounds %T10ObjectiveC8ObjCBoolV, ptr [[PTR0]], {{i.*}} 0, {{i.*}} 0
-// arm64-watchos:  [[PTR2:%.*]] = getelementptr inbounds %TSb, ptr [[PTR1]], {{i.*}} 0, {{i.*}} 0
+// arm64-watchos:  [[PTR0:%.*]] = getelementptr inbounds{{.*}} %TSo14FiveByteStructV, ptr [[COERCED]], {{i.*}} 0, {{i.*}} 0
+// arm64-watchos:  [[PTR1:%.*]] = getelementptr inbounds{{.*}} %T10ObjectiveC8ObjCBoolV, ptr [[PTR0]], {{i.*}} 0, {{i.*}} 0
+// arm64-watchos:  [[PTR2:%.*]] = getelementptr inbounds{{.*}} %TSb, ptr [[PTR1]], {{i.*}} 0, {{i.*}} 0
 // arm64-watchos:  store i8 0, ptr [[PTR2]], align 8
 // arm64-watchos:  [[ARG:%.*]] = load i64, ptr [[COERCED]]
 // arm64-watchos:  call void @objc_msgSend(ptr {{.*}}, ptr {{.*}}, i64 [[ARG]])
diff --git a/test/IRGen/abitypes_x86_64.swift b/test/IRGen/abitypes_x86_64.swift
index 80314b3fbad3a..04400c2f92d91 100644
--- a/test/IRGen/abitypes_x86_64.swift
+++ b/test/IRGen/abitypes_x86_64.swift
@@ -11,9 +11,9 @@ import c_gadget
 // x86_64: store float %1,
 // x86_64: store float %2,
 // x86_64: store float %3,
-// x86_64: [[T0:%.*]] = getelementptr inbounds { <2 x float>, <2 x float> }, ptr [[COERCED]], i32 0, i32 0
+// x86_64: [[T0:%.*]] = getelementptr inbounds{{.*}} { <2 x float>, <2 x float> }, ptr [[COERCED]], i32 0, i32 0
 // x86_64: [[FIRST_HALF:%.*]] = load <2 x float>, ptr [[T0]], align 8
-// x86_64: [[T0:%.*]] = getelementptr inbounds { <2 x float>, <2 x float> }, ptr [[COERCED]], i32 0, i32 1
+// x86_64: [[T0:%.*]] = getelementptr inbounds{{.*}} { <2 x float>, <2 x float> }, ptr [[COERCED]], i32 0, i32 1
 // x86_64: [[SECOND_HALF:%.*]] = load <2 x float>, ptr [[T0]], align 8
 // x86_64: [[RESULT:%.*]] = call float @MyRect_Area(<2 x float> [[FIRST_HALF]], <2 x float> [[SECOND_HALF]])
 // x86_64: ret float [[RESULT]]
diff --git a/test/IRGen/access_markers.sil b/test/IRGen/access_markers.sil
index 0fe492f18343f..255b417056a15 100644
--- a/test/IRGen/access_markers.sil
+++ b/test/IRGen/access_markers.sil
@@ -26,14 +26,14 @@ bb0(%0 : @guaranteed $A):
   // CHECK:      [[SCRATCH1:%.*]] = alloca [[BUFFER:.* x i8.]], align
   // CHECK:      [[SCRATCH2:%.*]] = alloca [[BUFFER]], align
 
-  // CHECK:      [[PROPERTY:%.*]] = getelementptr inbounds [[C]], ptr %0, i32 0, i32 1
+  // CHECK:      [[PROPERTY:%.*]] = getelementptr inbounds{{.*}} [[C]], ptr %0, i32 0, i32 1
   %2 = ref_element_addr %0 : $A, #A.property
 
   // CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 {{.*}}, ptr [[SCRATCH1]])
   // CHECK-NEXT: call void @swift_beginAccess(ptr [[PROPERTY]], ptr [[SCRATCH1]], [[SIZE:i(32|64)]] 33, ptr null)
   %3 = begin_access [modify] [dynamic] %2 : $*Int64
 
-  // CHECK-NEXT: getelementptr inbounds %Ts5Int64V, ptr [[PROPERTY]], i32 0, i32 0
+  // CHECK-NEXT: getelementptr inbounds{{.*}} %Ts5Int64V, ptr [[PROPERTY]], i32 0, i32 0
   // CHECK-NEXT: load i64, ptr
   %4 = load [trivial] %3 : $*Int64
 
@@ -45,7 +45,7 @@ bb0(%0 : @guaranteed $A):
   // CHECK-NEXT: call void @swift_beginAccess(ptr [[PROPERTY]], ptr [[SCRATCH2]], [[SIZE]] 32, ptr null)
   %6 = begin_access [read] [dynamic] %2 : $*Int64
 
-  // CHECK-NEXT: getelementptr inbounds %Ts5Int64V, ptr [[PROPERTY]], i32 0, i32 0
+  // CHECK-NEXT: getelementptr inbounds{{.*}} %Ts5Int64V, ptr [[PROPERTY]], i32 0, i32 0
   // CHECK-NEXT: load i64, ptr
   %7 = load [trivial] %6 : $*Int64
 
@@ -65,7 +65,7 @@ bb0(%0 : $A):
   // CHECK:      [[SCRATCH:%.*]] = alloca [[BUFFER:.* x i8.]], align
   %1 = alloc_stack $Builtin.UnsafeValueBuffer
 
-  // CHECK:      [[PROPERTY:%.*]] = getelementptr inbounds [[C]], ptr %0, i32 0, i32 1
+  // CHECK:      [[PROPERTY:%.*]] = getelementptr inbounds{{.*}} [[C]], ptr %0, i32 0, i32 1
   %2 = ref_element_addr %0 : $A, #A.property
 
   // CHECK-NEXT: call void @swift_beginAccess(ptr [[PROPERTY]], ptr [[SCRATCH]], [[SIZE]] 33, ptr null)
@@ -95,13 +95,13 @@ sil @testPairedBox : $(@guaranteed { var () }) -> () {
 bb0(%0 : ${ var () }):
   // CHECK: entry:
   %2 = project_box %0 : ${ var () }, 0
-  //  CHECK-NEXT: call {{.*}}void @writeEmptyTuple(ptr nocapture undef)
+  //  CHECK-NEXT: call {{.*}}void @writeEmptyTuple(ptr {{(nocapture|captures\(none\))}} undef)
   %3 = begin_access [modify] [dynamic] %2 : $*()
   %write_fn = function_ref @writeEmptyTuple : $@convention(thin) (@inout ()) -> ()
   apply %write_fn(%3) : $@convention(thin) (@inout ()) -> ()
   end_access %3 : $*()
 
-  // CHECK-NEXT: call {{.*}}void @readEmptyTuple(ptr noalias nocapture undef)
+  // CHECK-NEXT: call {{.*}}void @readEmptyTuple(ptr noalias {{(nocapture|captures\(none\))}} undef)
   %5 = begin_access [read] [dynamic] %2 : $*()
   %read_fn = function_ref @readEmptyTuple : $@convention(thin) (@in_guaranteed ()) -> ()
   apply %read_fn(%5) : $@convention(thin) (@in_guaranteed ()) -> ()
@@ -131,7 +131,7 @@ bb0(%0 : $A):
 sil @testNontracking : $(@guaranteed A) -> () {
 bb0(%0 : $A):
   %1 = alloc_stack $Int64
-  // CHECK:      [[PROPERTY:%.*]] = getelementptr inbounds [[C]], ptr %0, i32 0, i32 1
+  // CHECK:      [[PROPERTY:%.*]] = getelementptr inbounds{{.*}} [[C]], ptr %0, i32 0, i32 1
   %2 = ref_element_addr %0 : $A, #A.property
   // CHECK: call void @swift_beginAccess(ptr %{{.*}}, ptr %{{.*}}, [[SIZE]] 0, ptr null)
   %3 = begin_access [read] [dynamic] [no_nested_conflict] %2 : $*Int64
diff --git a/test/IRGen/access_markers_pc.sil b/test/IRGen/access_markers_pc.sil
index cb77a9b4c5f0b..53dcf0d91ccd7 100644
--- a/test/IRGen/access_markers_pc.sil
+++ b/test/IRGen/access_markers_pc.sil
@@ -21,7 +21,7 @@ sil_vtable A {}
 // CHECK-LABEL: define {{.*}}void @testUnpairedExternal(
 sil @testUnpairedExternal : $(@guaranteed A, @inout Builtin.UnsafeValueBuffer) -> () {
 bb0(%0 : $A, %1 : $*Builtin.UnsafeValueBuffer):
-  // CHECK:      [[PROPERTY:%.*]] = getelementptr inbounds [[C]], ptr %0, i32 0, i32 1
+  // CHECK:      [[PROPERTY:%.*]] = getelementptr inbounds{{.*}} [[C]], ptr %0, i32 0, i32 1
   %2 = ref_element_addr %0 : $A, #A.property
 
   // CHECK-NEXT: [[PC:%.*]] = call ptr @llvm.returnaddress(i32 0)
diff --git a/test/IRGen/actor_class.swift b/test/IRGen/actor_class.swift
index e4e7ec3b57dc9..5526840ca3a6b 100644
--- a/test/IRGen/actor_class.swift
+++ b/test/IRGen/actor_class.swift
@@ -41,8 +41,8 @@ public actor MyClass {
 }
 
 // CHECK-LABEL: define {{.*}}@"$s11actor_class7MyClassC1xSivg"
-// CHECK: [[T0:%.*]] = getelementptr inbounds %T11actor_class7MyClassC, ptr %0, i32 0, i32 2
-// CHECK: [[T1:%.*]] = getelementptr inbounds %TSi, ptr [[T0]], i32 0, i32 0
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} %T11actor_class7MyClassC, ptr %0, i32 0, i32 2
+// CHECK: [[T1:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[T0]], i32 0, i32 0
 // CHECK: load [[INT]], ptr [[T1]], align
 
 // CHECK-LABEL: define {{.*}}swiftcc ptr @"$s11actor_class7MyClassCACycfc"
diff --git a/test/IRGen/actor_class_objc.swift b/test/IRGen/actor_class_objc.swift
index 0e156c4c8ec29..eeca31a42f4fc 100644
--- a/test/IRGen/actor_class_objc.swift
+++ b/test/IRGen/actor_class_objc.swift
@@ -34,8 +34,8 @@ import Foundation
 }
 
 // CHECK-LABEL: define {{.*}} @"$s16actor_class_objc7MyClassC1xSivg"
-// CHECK: [[T0:%.*]] = getelementptr inbounds %T16actor_class_objc7MyClassC, ptr %0, i32 0, i32 2
-// CHECK: [[T1:%.*]] = getelementptr inbounds %TSi, ptr [[T0]], i32 0, i32 0
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} %T16actor_class_objc7MyClassC, ptr %0, i32 0, i32 2
+// CHECK: [[T1:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[T0]], i32 0, i32 0
 // CHECK: load [[INT]], ptr [[T1]], align
 
 // CHECK-LABEL: define {{.*}}swiftcc ptr @"$s16actor_class_objc7MyClassCACycfc"
diff --git a/test/IRGen/actor_class_objc_backdeploy.swift b/test/IRGen/actor_class_objc_backdeploy.swift
index ab2c4b3a95698..80a3c9a9b4a4d 100644
--- a/test/IRGen/actor_class_objc_backdeploy.swift
+++ b/test/IRGen/actor_class_objc_backdeploy.swift
@@ -40,8 +40,8 @@ import Foundation
 
 
 // CHECK-LABEL: define {{.*}} @"$s16actor_class_objc7MyClassC1xSivg"
-// CHECK: [[T0:%.*]] = getelementptr inbounds %T16actor_class_objc7MyClassC, ptr %0, i32 0, i32 2
-// CHECK: [[T1:%.*]] = getelementptr inbounds %TSi, ptr [[T0]], i32 0, i32 0
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} %T16actor_class_objc7MyClassC, ptr %0, i32 0, i32 2
+// CHECK: [[T1:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[T0]], i32 0, i32 0
 // CHECK: load [[INT]], ptr [[T1]], align
 
 // CHECK-LABEL: define {{.*}}swiftcc ptr @"$s16actor_class_objc7MyClassCACycfc"
diff --git a/test/IRGen/addressable.swift b/test/IRGen/addressable.swift
new file mode 100644
index 0000000000000..b008fc3b25f39
--- /dev/null
+++ b/test/IRGen/addressable.swift
@@ -0,0 +1,34 @@
+// RUN: %target-swift-frontend -module-name A -emit-ir -primary-file %s \
+// RUN: -enable-experimental-feature Lifetimes \
+// RUN: -enable-experimental-feature AddressableTypes \
+// RUN: | %FileCheck %s
+
+// REQUIRES: swift_feature_AddressableTypes
+// REQUIRES: swift_feature_Lifetimes
+
+public struct NE: ~Escapable {}
+
+@_addressableForDependencies
+public struct Holder {}
+
+@_silgen_name("holder_NE")
+@_lifetime(borrow holder)
+func getNE(_ holder: Holder) -> NE
+
+@_silgen_name("holder_mut_NE")
+@_lifetime(&holder)
+func getMutNE(_ holder: inout Holder) -> NE
+
+// The parameter cannot be 'nocapture'.
+//
+// CHECK-LABEL: define{{.*}} swiftcc void @"$s1A17testAddressableInyAA2NEVAA6HolderVF"(ptr noalias %0)
+public func testAddressableIn(_ holder: Holder) -> NE {
+  getNE(holder)
+}
+
+// The parameter cannot be 'nocapture'.
+//
+// CHECK-LABEL: define{{.*}} swiftcc void @"$s1A20testAddressableInoutyAA2NEVAA6HolderVzF"(ptr %0)
+public func testAddressableInout(_ holder: inout Holder) -> NE {
+  getMutNE(&holder)
+}
diff --git a/test/IRGen/addressable_for_dependencies_metadata.swift b/test/IRGen/addressable_for_dependencies_metadata.swift
new file mode 100644
index 0000000000000..4bba2bfef0f9d
--- /dev/null
+++ b/test/IRGen/addressable_for_dependencies_metadata.swift
@@ -0,0 +1,19 @@
+// RUN: %empty-directory(%t)
+// RUN: %{python} %utils/chex.py < %s > %t/test.swift
+// RUN: %target-swift-frontend -enable-experimental-feature AddressableTypes -emit-ir %s | %FileCheck %t/test.swift
+
+// REQUIRES: swift_feature_AddressableTypes
+
+@_addressableForDependencies
+struct DirectlyAFD {
+    var x: Int32
+}
+// CHECK-LABEL: @"$s{{.*}}11DirectlyAFDVWV" =
+// -- 0x0200_0000: addressable for dependencies
+// CHECK-SAME: , [[WORD:i(64|32)]] 4, [[WORD]] 4, <i32 0x0200_0003>, i32 0 }
+
+struct IndirectlyAFD {
+    var directly: DirectlyAFD
+}
+// CHECK-LABEL: @"$s{{.*}}13IndirectlyAFDVWV" =
+// CHECK-SAME: , [[WORD:i(64|32)]] 4, [[WORD]] 4, <i32 0x0200_0003>, i32 0 }
diff --git a/test/IRGen/alignment.sil b/test/IRGen/alignment.sil
index 820435e448251..461850a8a4617 100644
--- a/test/IRGen/alignment.sil
+++ b/test/IRGen/alignment.sil
@@ -57,10 +57,10 @@ entry:
   store %w to %d : $*NoPayload
 
   // CHECK: load i32{{.*}}, align 16
-  // CHECK: load i1{{.*}}, align 4
+  // CHECK: load i8{{.*}}, align 4
   %v = load %e : $*SinglePayload
   // CHECK: store i32{{.*}}, align 16
-  // CHECK: store i1{{.*}}, align 4
+  // CHECK: store i8{{.*}}, align 4
   store %v to %e : $*SinglePayload
 
   // CHECK: load i32{{.*}}, align 16
diff --git a/test/IRGen/annotated_cond_fail.swift b/test/IRGen/annotated_cond_fail.swift
index bb754384aa3c9..ef50e578426da 100644
--- a/test/IRGen/annotated_cond_fail.swift
+++ b/test/IRGen/annotated_cond_fail.swift
@@ -19,7 +19,7 @@ public func test(_ a: [Int], _ i: Int) -> Int {
 
 // CHECK:  [[SIZE_ADDR:%.*]] = getelementptr
 // CHECK:  [[SIZE:%.*]] = load i64, ptr [[SIZE_ADDR]]
-// CHECK:  [[C1:%.*]] = icmp ult i64 [[IDX]], [[SIZE]]
+// CHECK:  [[C1:%.*]] = icmp samesign ult i64 [[IDX]], [[SIZE]]
 // CHECK:  br i1 [[C1]], {{.*}}!annotation ![[ARRAY_INDEX_OUT_OF_BOUNDS]]
 
 
diff --git a/test/IRGen/archetype_resilience.sil b/test/IRGen/archetype_resilience.sil
index e67f5382cc625..b69f04afc318a 100644
--- a/test/IRGen/archetype_resilience.sil
+++ b/test/IRGen/archetype_resilience.sil
@@ -1,10 +1,9 @@
-// REQUIRES: CPU=x86_64
 // REQUIRES: OS=macosx
 
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -enable-library-evolution -emit-module-path=%t/resilient_struct.swiftmodule -module-name=resilient_struct %S/../Inputs/resilient_struct.swift
 // RUN: %target-swift-frontend -emit-module -enable-library-evolution -emit-module-path=%t/resilient_enum.swiftmodule -module-name=resilient_enum -I %t %S/../Inputs/resilient_enum.swift
-// RUN: %target-swift-frontend -disable-type-layout -I %t -emit-ir -enable-library-evolution %s | %FileCheck %s
+// RUN: %target-swift-frontend -disable-type-layout -I %t -Xllvm -sil-disable-pass=mandatory-temp-rvalue-elimination -emit-ir -enable-library-evolution %s | %FileCheck %s
 
 sil_stage canonical
 
diff --git a/test/IRGen/arg_and_result_peepholes.swift b/test/IRGen/arg_and_result_peepholes.swift
index 4e3c6337d844d..ee8dc3ab1d12f 100644
--- a/test/IRGen/arg_and_result_peepholes.swift
+++ b/test/IRGen/arg_and_result_peepholes.swift
@@ -10,13 +10,13 @@
 // CHECK:   [[TMP2:%.*]] = alloca %TSo9BigStructV
 // CHECK:   [[CALL:%.*]] = alloca %TSo9BigStructV
 // CHECK:   call void @llvm.lifetime.start.p0(i64 256, ptr [[TMP]])
-// CHECK:   [[A1:%.*]] = getelementptr inbounds { i64, i64, i64, i64 }, ptr [[TMP]], i32 0, i32 0
+// CHECK:   [[A1:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64, i64 }, ptr [[TMP]], i32 0, i32 0
 // CHECK:   store i64 %0, ptr [[A1]]
-// CHECK:   [[A2:%.*]] = getelementptr inbounds { i64, i64, i64, i64 }, ptr [[TMP]], i32 0, i32 1
+// CHECK:   [[A2:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64, i64 }, ptr [[TMP]], i32 0, i32 1
 // CHECK:   store i64 %1, ptr [[A2]]
-// CHECK:   [[A3:%.*]] = getelementptr inbounds { i64, i64, i64, i64 }, ptr [[TMP]], i32 0, i32 2
+// CHECK:   [[A3:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64, i64 }, ptr [[TMP]], i32 0, i32 2
 // CHECK:   store i64 %2, ptr [[A3]]
-// CHECK:   [[A4:%.*]] = getelementptr inbounds { i64, i64, i64, i64 }, ptr [[TMP]], i32 0, i32 3
+// CHECK:   [[A4:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64, i64 }, ptr [[TMP]], i32 0, i32 3
 // CHECK:   store i64 %3, ptr [[A4]]
 
 // CHECK:  call void @llvm.lifetime.start.p0(i64 32, ptr [[ARG_MEM]])
@@ -30,13 +30,13 @@
 
 // CHECK: call void @llvm.memcpy.p0.p0.i64(ptr{{.*}} [[RES_MEM]], ptr{{.*}} [[CALL]], i64 32, i1 false)
 
-// CHECK:  [[A5:%.*]] = getelementptr inbounds { i64, i64, i64, i64 }, ptr [[RES_MEM]], i32 0, i32 0
+// CHECK:  [[A5:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64, i64 }, ptr [[RES_MEM]], i32 0, i32 0
 // CHECK:  [[R1:%.*]] = load i64, ptr [[A5]]
-// CHECK:  [[A6:%.*]] = getelementptr inbounds { i64, i64, i64, i64 }, ptr [[RES_MEM]], i32 0, i32 1
+// CHECK:  [[A6:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64, i64 }, ptr [[RES_MEM]], i32 0, i32 1
 // CHECK:  [[R2:%.*]] = load i64, ptr [[A6]]
-// CHECK:  [[A7:%.*]] = getelementptr inbounds { i64, i64, i64, i64 }, ptr [[RES_MEM]], i32 0, i32 2
+// CHECK:  [[A7:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64, i64 }, ptr [[RES_MEM]], i32 0, i32 2
 // CHECK:  [[R3:%.*]] = load i64, ptr [[A7]]
-// CHECK:  [[A8:%.*]] = getelementptr inbounds { i64, i64, i64, i64 }, ptr [[RES_MEM]], i32 0, i32 3
+// CHECK:  [[A8:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64, i64 }, ptr [[RES_MEM]], i32 0, i32 3
 // CHECK:  [[R4:%.*]] = load i64, ptr [[A8]]
 // CHECK:  call void @llvm.lifetime.end.p0(i64 32, ptr [[ARG_MEM]])
 // CHECK:  call void @llvm.lifetime.end.p0(i64 32, ptr [[RES_MEM]])
diff --git a/test/IRGen/argument_attrs.sil b/test/IRGen/argument_attrs.sil
index ee82eb7eb4ddb..4e2a98d6b732f 100644
--- a/test/IRGen/argument_attrs.sil
+++ b/test/IRGen/argument_attrs.sil
@@ -4,49 +4,49 @@ import Builtin
 
 struct Huge { var x, y, z, w, a, b, c, d, e, f: Builtin.Int32 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @arguments_in_def(ptr nocapture dereferenceable(4) %0, ptr noalias nocapture dereferenceable(4) %1, ptr noalias nocapture dereferenceable(4) %2, ptr noalias nocapture dereferenceable(40) %3, ptr noalias %4, ptr noalias nocapture %5, ptr %T)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @arguments_in_def(ptr captures(none) dereferenceable(4) %0, ptr noalias captures(none) dereferenceable(4) %1, ptr noalias captures(none) dereferenceable(4) %2, ptr noalias captures(none) dereferenceable(40) %3, ptr noalias %4, ptr noalias captures(none) %5, ptr %T)
 sil @arguments_in_def : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> () {
 entry(%1 : $*Builtin.Int32, %2 : $*Builtin.Int32, %3 : $*Builtin.Int32, %4 : $Huge, %5 : $*T, %6 : $*()):
-  // CHECK: call swiftcc void @arguments_in_decl(ptr nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias nocapture {{%.*}}, ptr %T)
+  // CHECK: call swiftcc void @arguments_in_decl(ptr captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias captures(none) {{%.*}}, ptr %T)
   %f = function_ref @arguments_in_decl : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> ()
   %x = apply %f<T>(%1, %2, %3, %4, %5, %6) : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> ()
-  // CHECK: call swiftcc void @arguments_in_def(ptr nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias nocapture {{%.*}}, ptr %T)
+  // CHECK: call swiftcc void @arguments_in_def(ptr captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias captures(none) {{%.*}}, ptr %T)
   %g = function_ref @arguments_in_def : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> ()
   %y = apply %g<T>(%1, %2, %3, %4, %5, %6) : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> ()
   return undef : $()
 }
 
-// CHECK-LABEL: declare{{( dllimport)?}} swiftcc void @arguments_in_decl(ptr nocapture dereferenceable(4), ptr noalias nocapture dereferenceable(4), ptr noalias nocapture dereferenceable(4), ptr noalias nocapture dereferenceable(40), ptr noalias, ptr noalias nocapture, ptr)
+// CHECK-LABEL: declare{{( dllimport)?}} swiftcc void @arguments_in_decl(ptr captures(none) dereferenceable(4), ptr noalias captures(none) dereferenceable(4), ptr noalias captures(none) dereferenceable(4), ptr noalias captures(none) dereferenceable(40), ptr noalias, ptr noalias captures(none), ptr)
 sil @arguments_in_decl : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> ()
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @arguments_in_def_out(ptr noalias nocapture sret({{.*}}) %0, ptr nocapture dereferenceable(4) %1, ptr noalias nocapture dereferenceable(4) %2, ptr noalias nocapture dereferenceable(4) %3, ptr noalias nocapture dereferenceable(40) %4, ptr noalias %5, ptr noalias nocapture %6, ptr %T)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @arguments_in_def_out(ptr noalias sret({{.*}}) captures(none) %0, ptr captures(none) dereferenceable(4) %1, ptr noalias captures(none) dereferenceable(4) %2, ptr noalias captures(none) dereferenceable(4) %3, ptr noalias captures(none) dereferenceable(40) %4, ptr noalias %5, ptr noalias captures(none) %6, ptr %T)
 sil @arguments_in_def_out : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> @out Builtin.Int32 {
 entry(%0 : $*Builtin.Int32, %1 : $*Builtin.Int32, %2 : $*Builtin.Int32, %3 : $*Builtin.Int32, %4 : $Huge, %5 : $*T, %6 : $*()):
-  // CHECK: call swiftcc void @arguments_in_decl_out(ptr noalias nocapture sret({{.*}}) {{%.*}}, ptr nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias nocapture {{%.*}}, ptr {{%.*}})
+  // CHECK: call swiftcc void @arguments_in_decl_out(ptr noalias sret({{.*}}) captures(none) {{%.*}}, ptr captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias captures(none) {{%.*}}, ptr {{%.*}})
   %f = function_ref @arguments_in_decl_out : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> @out Builtin.Int32
   %x = apply %f<T>(%0, %1, %2, %3, %4, %5, %6) : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> @out Builtin.Int32
-  // CHECK: call swiftcc void @arguments_in_def_out(ptr noalias nocapture sret({{.*}}) {{%.*}}, ptr nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias nocapture {{%.*}}, ptr {{%.*}})
+  // CHECK: call swiftcc void @arguments_in_def_out(ptr noalias sret({{.*}}) captures(none) {{%.*}}, ptr captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias captures(none) {{%.*}}, ptr {{%.*}})
   %g = function_ref @arguments_in_def_out : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> @out Builtin.Int32
   %y = apply %g<T>(%0, %1, %2, %3, %4, %5, %6) : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> @out Builtin.Int32
   return undef : $()
 }
 
-// CHECK-LABEL: declare{{( dllimport)?}} swiftcc void @arguments_in_decl_out(ptr noalias nocapture sret({{.*}}), ptr nocapture dereferenceable(4), ptr noalias nocapture dereferenceable(4), ptr noalias nocapture dereferenceable(4), ptr noalias nocapture dereferenceable(40), ptr noalias, ptr noalias nocapture, ptr)
+// CHECK-LABEL: declare{{( dllimport)?}} swiftcc void @arguments_in_decl_out(ptr noalias sret({{.*}}) captures(none), ptr captures(none) dereferenceable(4), ptr noalias captures(none) dereferenceable(4), ptr noalias captures(none) dereferenceable(4), ptr noalias captures(none) dereferenceable(40), ptr noalias, ptr noalias captures(none), ptr)
 sil @arguments_in_decl_out : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> @out Builtin.Int32
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @arguments_in_def_huge_ret(ptr noalias nocapture sret({{.*}}V) %0, ptr nocapture dereferenceable(4) %1, ptr noalias nocapture dereferenceable(4) %2, ptr noalias nocapture dereferenceable(4) %3, ptr noalias nocapture dereferenceable(40) %4, ptr noalias %5, ptr noalias nocapture %6, ptr %T)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @arguments_in_def_huge_ret(ptr noalias sret({{.*}}V) captures(none) %0, ptr captures(none) dereferenceable(4) %1, ptr noalias captures(none) dereferenceable(4) %2, ptr noalias captures(none) dereferenceable(4) %3, ptr noalias captures(none) dereferenceable(40) %4, ptr noalias %5, ptr noalias captures(none) %6, ptr %T)
 sil @arguments_in_def_huge_ret : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> Huge {
 entry(%1 : $*Builtin.Int32, %2 : $*Builtin.Int32, %3 : $*Builtin.Int32, %4 : $Huge, %5 : $*T, %6 : $*()):
   %f = function_ref @arguments_in_decl_huge_ret : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> Huge
-  // CHECK: call swiftcc void @arguments_in_decl_huge_ret(ptr noalias nocapture sret({{.*}}) {{%.*}}, ptr nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias nocapture {{%.*}}, ptr {{%.*}})
+  // CHECK: call swiftcc void @arguments_in_decl_huge_ret(ptr noalias sret({{.*}}) captures(none) {{%.*}}, ptr captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias captures(none) {{%.*}}, ptr {{%.*}})
   %x = apply %f<T>(%1, %2, %3, %4, %5, %6) : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> Huge
-  // CHECK: call swiftcc void @arguments_in_def_huge_ret(ptr noalias nocapture sret({{.*}}) {{%.*}}, ptr nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(4) {{%.*}}, ptr noalias nocapture dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias nocapture {{%.*}}, ptr {{%.*}})
+  // CHECK: call swiftcc void @arguments_in_def_huge_ret(ptr noalias sret({{.*}}) captures(none) {{%.*}}, ptr captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(4) {{%.*}}, ptr noalias captures(none) dereferenceable(40) {{%.*}}, ptr noalias {{%.*}}, ptr noalias captures(none) {{%.*}}, ptr {{%.*}})
   %g = function_ref @arguments_in_def_huge_ret : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> Huge
   %y = apply %g<T>(%1, %2, %3, %4, %5, %6) : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> Huge
   return %y : $Huge
 }
 
-// CHECK-LABEL: declare{{( dllimport)?}} swiftcc void @arguments_in_decl_huge_ret(ptr noalias nocapture sret({{.*}}), ptr nocapture dereferenceable(4), ptr noalias nocapture dereferenceable(4), ptr noalias nocapture dereferenceable(4), ptr noalias nocapture dereferenceable(40), ptr noalias, ptr noalias nocapture, ptr)
+// CHECK-LABEL: declare{{( dllimport)?}} swiftcc void @arguments_in_decl_huge_ret(ptr noalias sret({{.*}}) captures(none), ptr captures(none) dereferenceable(4), ptr noalias captures(none) dereferenceable(4), ptr noalias captures(none) dereferenceable(4), ptr noalias captures(none) dereferenceable(40), ptr noalias, ptr noalias captures(none), ptr)
 sil @arguments_in_decl_huge_ret : $@convention(thin) <T> (@inout Builtin.Int32, @in Builtin.Int32, @in_guaranteed Builtin.Int32, Huge, @in T, @in ()) -> Huge
 
 
diff --git a/test/IRGen/asmname.swift b/test/IRGen/asmname.swift
index 50d40110adfb7..6f1236dd4818d 100644
--- a/test/IRGen/asmname.swift
+++ b/test/IRGen/asmname.swift
@@ -1,9 +1,8 @@
-// RUN: %target-swift-frontend -enable-experimental-feature ABIAttribute %s -emit-ir > %t.ir
+// RUN: %target-swift-frontend %s -emit-ir > %t.ir
 // RUN: %FileCheck --input-file %t.ir %s
 // RUN: %FileCheck --check-prefix NEGATIVE --input-file %t.ir %s
 
 // REQUIRES: CPU=i386 || CPU=x86_64 || CPU=arm64
-// REQUIRES: swift_feature_ABIAttribute
 
 // Non-Swift _silgen_name definitions
 
diff --git a/test/IRGen/async/async_context_projection_arm64e.swift b/test/IRGen/async/async_context_projection_arm64e.swift
new file mode 100644
index 0000000000000..35be31fd4bea1
--- /dev/null
+++ b/test/IRGen/async/async_context_projection_arm64e.swift
@@ -0,0 +1,25 @@
+// RUN: %target-swift-frontend -emit-irgen %s | %FileCheck %s
+
+// REQUIRES: CPU=arm64e
+
+public func callee() async -> Int {
+    return 5
+}
+
+public func caller() async {
+   let r = await callee()
+   print(r)
+}
+
+
+// CHECK: define swifttailcc void @"$s31async_context_projection_arm64e6calleryyYaF"(ptr swiftasync %0)
+// CHECK:  [[CURR_ASYNC_CTXT:%.*]] = alloca ptr
+// CHECK:  [[SUSPEND_RES:%.*]] = call { ptr, i64 } (i32, ptr, ptr, ...) @llvm.coro.suspend.async.sl_p0i64s(i32 0, ptr {{.*}}, ptr @__swift_async_resume_project_context, ptr @"$s31async_context_projection_arm64e6calleryyYaF{{.*}}", ptr @"$s31async_context_projection_arm64e6calleeSiyYaF", ptr {{.*}})
+// CHECK:  [[CALLEE_CTXT:%.*]] = extractvalue { ptr, i64 } [[SUSPEND_RES]], 0
+// CHECK:  [[CALLER_CTXT:%.*]] = load ptr, ptr [[CALLEE_CTXT]]
+// CHECK:  [[CALLER_CTXT_ADDR:%.*]] = ptrtoint ptr [[CALLEE_CTXT]] to i64
+// CHECK:  [[DIS:%.*]] = call i64 @llvm.ptrauth.blend(i64 [[CALLER_CTXT_ADDR]], i64 48546)
+// CHECK:  [[CALLER_CTXT_PTRAUTH:%.*]] = ptrtoint ptr [[CALLER_CTXT]] to i64
+// CHECK:  [[CALLER_CTXT_AUTH:%.*]] = call i64 @llvm.ptrauth.auth(i64 [[CALLER_CTXT_PTRAUTH]], i32 2, i64 [[DIS]])
+// CHECK:  [[CALLER_CTXT_PTR:%.*]] = inttoptr i64 [[CALLER_CTXT_AUTH]] to ptr
+// CHECK:  store ptr [[CALLER_CTXT_PTR]], ptr [[CURR_ASYNC_CTXT]]
diff --git a/test/IRGen/async/builtins.sil b/test/IRGen/async/builtins.sil
index 9ad7f105d3919..e9bbea8449606 100644
--- a/test/IRGen/async/builtins.sil
+++ b/test/IRGen/async/builtins.sil
@@ -10,6 +10,10 @@ import Builtin
 import Swift
 import _Concurrency
 
+struct Pair<T> {
+  var value: (T, T)
+}
+
 // CHECK-LABEL: define hidden swift{{(tail)?}}cc void @get_task(ptr swiftasync %0)
 sil hidden [ossa] @get_task : $@async @convention(thin) () -> @owned Builtin.NativeObject {
 bb0:
@@ -51,15 +55,15 @@ sil hidden [ossa] @launch_future_on : $@convention(method) <T> (Int, Builtin.Exe
 bb0(%flags : $Int, %serialExecutor : $Builtin.Executor, %taskFunction: @owned $@async @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error Error) for <T>):
   // CHECK: [[EXECUTOR_RECORD:%.*]] = alloca %swift.serial_executor_task_option
   // CHECK-NOT: br i1
-  // CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds %swift.serial_executor_task_option, ptr [[EXECUTOR_RECORD]], i32 0, i32 0
-  // CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
+  // CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.serial_executor_task_option, ptr [[EXECUTOR_RECORD]], i32 0, i32 0
+  // CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
   // CHECK: store [[INT]] 0, ptr [[FLAGS_GEP]], align
-  // CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
+  // CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
   // CHECK: store ptr null, ptr [[PARENT_GEP]], align
-  // CHECK: [[EXECUTOR_GEP:%.*]] = getelementptr inbounds %swift.serial_executor_task_option, ptr [[EXECUTOR_RECORD]], i32 0, i32 1
-  // CHECK: [[EXECUTOR_IDENT_GEP:%.*]] = getelementptr inbounds %swift.executor, ptr [[EXECUTOR_GEP]], i32 0, i32 0
+  // CHECK: [[EXECUTOR_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.serial_executor_task_option, ptr [[EXECUTOR_RECORD]], i32 0, i32 1
+  // CHECK: [[EXECUTOR_IDENT_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.executor, ptr [[EXECUTOR_GEP]], i32 0, i32 0
   // CHECK: store [[INT]] %1, ptr [[EXECUTOR_IDENT_GEP]], align
-  // CHECK: [[EXECUTOR_IMPL_GEP:%.*]] = getelementptr inbounds %swift.executor, ptr [[EXECUTOR_GEP]], i32 0, i32 1
+  // CHECK: [[EXECUTOR_IMPL_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.executor, ptr [[EXECUTOR_GEP]], i32 0, i32 1
   // CHECK: store [[INT]] %2, ptr [[EXECUTOR_IMPL_GEP]], align
   // CHECK: [[NEW_TASK_AND_CONTEXT:%.*]] = call swift{{(tail)?}}cc %swift.async_task_and_context @swift_task_create([[INT]] %0, ptr [[EXECUTOR_RECORD]], ptr %T, ptr %3, ptr %4)
   %optSerialExecutor = enum $Optional<Builtin.Executor>, #Optional.some, %serialExecutor : $Builtin.Executor
@@ -76,12 +80,12 @@ bb0(%flags : $Int, %serialExecutor : $Builtin.Executor, %taskFunction: @owned $@
 // CHECK-LABEL: define hidden swift{{(tail)?}}cc void @launch_future_in_group
 // CHECK: [[OPTIONS:%.*]] = alloca %swift.task_group_task_option
 // CHECK-NOT: br i1
-// CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds %swift.task_group_task_option, ptr [[OPTIONS]], i32 0, i32 0
-// CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
+// CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_group_task_option, ptr [[OPTIONS]], i32 0, i32 0
+// CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
 // CHECK: store [[INT]] 1, ptr [[FLAGS_GEP]], align
-// CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
+// CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
 // CHECK: store ptr null, ptr [[PARENT_GEP]], align
-// CHECK: [[GROUP_GEP:%.*]] = getelementptr inbounds %swift.task_group_task_option, ptr [[OPTIONS]], i32 0, i32 1
+// CHECK: [[GROUP_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_group_task_option, ptr [[OPTIONS]], i32 0, i32 1
 // CHECK: store ptr %0, ptr [[GROUP_GEP]], align
 // CHECK: call swiftcc %swift.async_task_and_context @swift_task_create([[INT]] %3, ptr [[OPTIONS]],
 sil hidden @launch_future_in_group : $@convention(thin) (Builtin.RawPointer, @owned @async @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error Error) for <Int>, Int) -> () {
@@ -106,12 +110,12 @@ bb0(%flags : $Int, %optTaskGroup : $Optional<Builtin.RawPointer>, %taskFunction:
   // CHECK: br i1 [[GROUP_IS_NULL]], label %task_group.cont, label %task_group.some
   // CHECK: task_group.some:
   // CHECK: [[GROUP:%.*]] = inttoptr [[INT]] %1 to ptr
-  // CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds %swift.task_group_task_option, ptr [[OPTIONS]], i32 0, i32 0
-  // CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
+  // CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_group_task_option, ptr [[OPTIONS]], i32 0, i32 0
+  // CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
   // CHECK: store [[INT]] 1, ptr [[FLAGS_GEP]], align
-  // CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
+  // CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
   // CHECK: store ptr null, ptr [[PARENT_GEP]], align
-  // CHECK: [[GROUP_GEP:%.*]] = getelementptr inbounds %swift.task_group_task_option, ptr [[OPTIONS]], i32 0, i32 1
+  // CHECK: [[GROUP_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_group_task_option, ptr [[OPTIONS]], i32 0, i32 1
   // CHECK: store ptr [[GROUP]], ptr [[GROUP_GEP]], align
   // CHECK: br label %task_group.cont
   // CHECK: task_group.cont:
@@ -157,23 +161,23 @@ bb0(%taskGroup : $Builtin.RawPointer, %taskExecutor : $Builtin.Executor, %taskFu
   // CHECK: [[EXECUTOR_RECORD:%.*]] = alloca %swift.task_executor_task_option
   // CHECK-NOT: br i1
 
-  // CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds %swift.task_group_task_option, ptr [[GROUP_RECORD]], i32 0, i32 0
-  // CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
+  // CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_group_task_option, ptr [[GROUP_RECORD]], i32 0, i32 0
+  // CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
   // CHECK: store [[INT]] 1, ptr [[FLAGS_GEP]], align
-  // CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
+  // CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
   // CHECK: store ptr null, ptr [[PARENT_GEP]], align
-  // CHECK: [[GROUP_GEP:%.*]] = getelementptr inbounds %swift.task_group_task_option, ptr [[GROUP_RECORD]], i32 0, i32 1
+  // CHECK: [[GROUP_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_group_task_option, ptr [[GROUP_RECORD]], i32 0, i32 1
   // CHECK: store ptr %0, ptr [[GROUP_GEP]], align
 
-  // CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds %swift.task_executor_task_option, ptr [[EXECUTOR_RECORD]], i32 0, i32 0
-  // CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
+  // CHECK: [[BASE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_executor_task_option, ptr [[EXECUTOR_RECORD]], i32 0, i32 0
+  // CHECK: [[FLAGS_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 0
   // CHECK: store [[INT]] 5, ptr [[FLAGS_GEP]], align
-  // CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
+  // CHECK: [[PARENT_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_option, ptr [[BASE_GEP]], i32 0, i32 1
   // CHECK: store ptr [[GROUP_RECORD]], ptr [[PARENT_GEP]], align
-  // CHECK: [[EXECUTOR_GEP:%.*]] = getelementptr inbounds %swift.task_executor_task_option, ptr [[EXECUTOR_RECORD]], i32 0, i32 1
-  // CHECK: [[EXECUTOR_IDENT_GEP:%.*]] = getelementptr inbounds %swift.executor, ptr [[EXECUTOR_GEP]], i32 0, i32 0
+  // CHECK: [[EXECUTOR_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.task_executor_task_option, ptr [[EXECUTOR_RECORD]], i32 0, i32 1
+  // CHECK: [[EXECUTOR_IDENT_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.executor, ptr [[EXECUTOR_GEP]], i32 0, i32 0
   // CHECK: store [[INT]] %1, ptr [[EXECUTOR_IDENT_GEP]], align
-  // CHECK: [[EXECUTOR_IMPL_GEP:%.*]] = getelementptr inbounds %swift.executor, ptr [[EXECUTOR_GEP]], i32 0, i32 1
+  // CHECK: [[EXECUTOR_IMPL_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.executor, ptr [[EXECUTOR_GEP]], i32 0, i32 1
   // CHECK: store [[INT]] %2, ptr [[EXECUTOR_IMPL_GEP]], align
 
   // CHECK: call swift{{(tail)?}}cc %swift.async_task_and_context @swift_task_create([[INT]] %5, ptr [[EXECUTOR_RECORD]]
@@ -202,9 +206,9 @@ bb0(%flags : $Int, %taskGroup : $Builtin.RawPointer, %taskFunction: @owned $@asy
 // CHECK-LABEL: define hidden swiftcc void @resume_nonthrowing_continuation
 sil hidden [ossa] @resume_nonthrowing_continuation : $(@in Builtin.NativeObject, Builtin.RawUnsafeContinuation) -> () {
 bb0(%0 : $*Builtin.NativeObject, %1 : $Builtin.RawUnsafeContinuation):
-  // CHECK: [[CONTEXT_SLOT:%.*]] = getelementptr inbounds %swift.task, ptr %1, i32 0, i32 8
+  // CHECK: [[CONTEXT_SLOT:%.*]] = getelementptr inbounds{{.*}} %swift.task, ptr %1, i32 0, i32 8
   // CHECK-NEXT: [[CONTEXT_OPAQUE:%.*]] = load ptr, ptr [[CONTEXT_SLOT]], align
-  // CHECK-NEXT: [[RESULT_ADDR_SLOT:%.*]] = getelementptr inbounds %swift.continuation_context, ptr [[CONTEXT_OPAQUE]], i32 0, i32 4
+  // CHECK-NEXT: [[RESULT_ADDR_SLOT:%.*]] = getelementptr inbounds{{.*}} %swift.continuation_context, ptr [[CONTEXT_OPAQUE]], i32 0, i32 4
   // CHECK-NEXT: [[RESULT_ADDR_OPAQUE:%.*]] = load ptr, ptr [[RESULT_ADDR_SLOT]], align
   // CHECK-NEXT: [[VALUE:%.*]] = load ptr, ptr %0, align
   // CHECK-NEXT: store ptr [[VALUE]], ptr [[RESULT_ADDR_OPAQUE]], align
@@ -218,9 +222,9 @@ bb0(%0 : $*Builtin.NativeObject, %1 : $Builtin.RawUnsafeContinuation):
 // CHECK-LABEL: define hidden swiftcc void @resume_throwing_continuation
 sil hidden [ossa] @resume_throwing_continuation : $(@in Builtin.NativeObject, Builtin.RawUnsafeContinuation) -> () {
 bb0(%0 : $*Builtin.NativeObject, %1 : $Builtin.RawUnsafeContinuation):
-  // CHECK: [[CONTEXT_SLOT:%.*]] = getelementptr inbounds %swift.task, ptr %1, i32 0, i32 8
+  // CHECK: [[CONTEXT_SLOT:%.*]] = getelementptr inbounds{{.*}} %swift.task, ptr %1, i32 0, i32 8
   // CHECK-NEXT: [[CONTEXT_OPAQUE:%.*]] = load ptr, ptr [[CONTEXT_SLOT]], align
-  // CHECK-NEXT: [[RESULT_ADDR_SLOT:%.*]] = getelementptr inbounds %swift.continuation_context, ptr [[CONTEXT_OPAQUE]], i32 0, i32 4
+  // CHECK-NEXT: [[RESULT_ADDR_SLOT:%.*]] = getelementptr inbounds{{.*}} %swift.continuation_context, ptr [[CONTEXT_OPAQUE]], i32 0, i32 4
   // CHECK-NEXT: [[RESULT_ADDR_OPAQUE:%.*]] = load ptr, ptr [[RESULT_ADDR_SLOT]], align
   // CHECK-NEXT: [[VALUE:%.*]] = load ptr, ptr %0, align
   // CHECK-NEXT: store ptr [[VALUE]], ptr [[RESULT_ADDR_OPAQUE]], align
@@ -241,6 +245,33 @@ bb0(%0 : @owned $Error, %1 : $Builtin.RawUnsafeContinuation):
   return %21 : $()
 }
 
+// CHECK-LABEL: define {{.*}} void @async_let_generic(
+sil public @async_let_generic : $@convention(thin) @async <T> () -> @out Pair<T> {
+bb0(%out : $*Pair<T>):
+  %1 = function_ref @async_let_generic_helper : $@convention(thin) @Sendable @async <τ_0_0> () -> (@out Pair<τ_0_0>, @error any Error)
+  %2 = thin_to_thick_function %1 to $@Sendable @async <τ_0_0> () -> (@out Pair<τ_0_0>, @error any Error)
+  %fn = convert_function %2 to $@async @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Pair<T>>
+  %outPtr = address_to_pointer %out to $Builtin.RawPointer
+  %scratch = enum $Optional<Builtin.RawPointer>, #Optional.none!enumelt
+
+  // We've set up a function that has no reason to request type metadata
+  // for Pair<T> except to pass it to swift_asyncLet_begin. Make sure that we
+  // request complete metadata.
+
+  // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s8builtins4PairVMa"([[INT]] 0, ptr %T)
+  // CHECK-NEXT:    [[METADATA:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
+  // CHECK-NEXT:    call swiftcc void @swift_asyncLet_begin({{.*}}, ptr [[METADATA]], {{.*}})
+  %asyncLet = builtin "startAsyncLetWithLocalBuffer"<Pair<T>>(%scratch, %fn, %outPtr) : $Builtin.RawPointer
+  %t1 = builtin "endAsyncLetLifetime"(%asyncLet, %fn) : $()
+  %result = tuple ()
+  return %result
+}
+
+sil private @async_let_generic_helper : $@convention(thin) @Sendable @async <T> () -> (@out Pair<T>, @error any Error) {
+bb0(%out : $*Pair<T>):
+  unreachable
+}
+
 // CHECK-LABEL: define hidden swift{{(tail)?}}cc  void @task_group_create_destroy
 sil hidden [ossa] @task_group_create_destroy : $@async () -> () {
 bb0:
@@ -258,6 +289,31 @@ bb0:
   return %21 : $()
 }
 
+// CHECK-LABEL: define hidden swift{{(tail)?}}cc  void @task_group_create_destroy_generic
+sil hidden [ossa] @task_group_create_destroy_generic : $@async <T> () -> () {
+bb0:
+  // CHECK:      [[TASKGROUP:%.*]] = alloca [32 x ptr], align 16
+  // CHECK: call void @llvm.lifetime.start.p0(i64 -1, ptr [[TASKGROUP]])
+
+  // We've set up a function that has no reason to request type metadata
+  // for Pair<T> except to pass it to swift_taskGroup_initialize. Make sure
+  // that we request complete metadata.
+
+  // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s8builtins4PairVMa"([[INT]] 0, ptr %T)
+  // CHECK-NEXT:    [[METADATA:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
+
+  // CHECK-NEXT: call swiftcc void @swift_taskGroup_initialize(ptr [[TASKGROUP]], ptr [[METADATA]])
+
+  %0 = metatype $@thin Pair<T>.Type
+  %1 = builtin "createTaskGroup"<Pair<T>>(%0: $@thin Pair<T>.Type) : $Builtin.RawPointer
+
+  // CHECK-NEXT: call swiftcc void @swift_taskGroup_destroy(ptr [[TASKGROUP]])
+  // CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 -1, ptr [[TASKGROUP]])
+  builtin "destroyTaskGroup"(%1 : $Builtin.RawPointer) : $()
+
+  %21 = tuple ()
+  return %21 : $()
+}
 
 // CHECK-LABEL: define{{.*}} swiftcc void @testRunInline(
 // CHECK-SAME:      ptr noalias sret(%swift.opaque) [[RESULT:%[^,]+]],
@@ -276,3 +332,25 @@ entry(%result : $*T, %closure : $@noescape @async @callee_guaranteed @substitute
   %void = builtin "taskRunInline"<T>(%result : $*T, %closure : $@noescape @async @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <T>) : $()
   return %void : $()
 }
+
+// CHECK-LABEL: define{{.*}} swiftcc void @testRunInlineGeneric(
+// CHECK-SAME:      ptr noalias sret(%swift.opaque) [[RESULT:%[^,]+]],
+// CHECK-SAME:      ptr [[CLOSURE:%[^,]+]],
+// CHECK-SAME:      ptr [[CLOSURE_CONTEXT:%[^,]+]],
+// CHECK-SAME:      ptr %T
+// CHECK-SAME:  {
+
+//   Make sure we request complete metadata.
+// CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s8builtins4PairVMa"([[INT]] 0, ptr %T)
+// CHECK-NEXT:    [[FUTURE_RESULT_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
+// CHECK:         call swiftcc void @swift_task_run_inline(
+// CHECK-SAME:        ptr [[RESULT]],
+// CHECK-SAME:        ptr [[CLOSURE]],
+// CHECK-SAME:        ptr [[CLOSURE_CONTEXT]],
+// CHECK-SAME:        ptr [[FUTURE_RESULT_TYPE]])
+// CHECK:       }
+sil hidden @testRunInlineGeneric : $@convention(thin) <T> (@noescape @async @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Pair<T>>) -> @out T {
+entry(%result : $*T, %closure : $@noescape @async @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Pair<T>>):
+  %void = builtin "taskRunInline"<Pair<T>>(%result : $*T, %closure : $@noescape @async @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Pair<T>>) : $()
+  return %void : $()
+}
diff --git a/test/IRGen/async/get_async_continuation.sil b/test/IRGen/async/get_async_continuation.sil
index 211df650e4e97..1d5da2ce47f12 100644
--- a/test/IRGen/async/get_async_continuation.sil
+++ b/test/IRGen/async/get_async_continuation.sil
@@ -23,8 +23,8 @@ bb0:
 //   Initialize the async continuation context:
 
 //   Initialize Parent.
-// CHECK: [[base_context:%.*]] = getelementptr inbounds %swift.continuation_context, ptr [[cont_context]], i32 0, i32 0
-// CHECK: [[context_addr:%.*]] = getelementptr inbounds %swift.context, ptr [[base_context]], i32 0, i32 0
+// CHECK: [[base_context:%.*]] = getelementptr inbounds{{.*}} %swift.continuation_context, ptr [[cont_context]], i32 0, i32 0
+// CHECK: [[context_addr:%.*]] = getelementptr inbounds{{.*}} %swift.context, ptr [[base_context]], i32 0, i32 0
 // CHECK: [[ctxt:%.*]] = load ptr, ptr [[ctxt_addr]]
 // CHECK-arm64e: [[ctxt_addr_int:%[0-9]+]] = ptrtoint ptr [[context_addr]] to i64
 // CHECK-arm64e: [[ptrauth_blend:%[0-9]+]]   = call i64 @llvm.ptrauth.blend(i64 [[ctxt_addr_int]], i64 48546)
@@ -35,12 +35,12 @@ bb0:
 // CHECK-x86_64: store ptr [[ctxt]], ptr [[context_addr]]
 
 //   Initialize NormalResult.
-// CHECK: [[result_addr:%.*]] = getelementptr inbounds %swift.continuation_context, ptr [[cont_context]], i32 0, i32 4
+// CHECK: [[result_addr:%.*]] = getelementptr inbounds{{.*}} %swift.continuation_context, ptr [[cont_context]], i32 0, i32 4
 // CHECK: store ptr [[result_storage]], ptr [[result_addr]]
 
 //   Initialize ResumeParent.
 // CHECK: [[resume_intrinsic:%.*]] = call ptr @llvm.coro.async.resume()
-// CHECK: [[continuation_fn_addr:%.*]] = getelementptr inbounds %swift.context, ptr [[base_context]], i32 0, i32 1
+// CHECK: [[continuation_fn_addr:%.*]] = getelementptr inbounds{{.*}} %swift.context, ptr [[base_context]], i32 0, i32 1
 // CHECK-arm64e: [[continuation_fn_addr_int:%[0-9]+]] = ptrtoint ptr [[continuation_fn_addr]] to i64
 // CHECK-arm64e: [[ptrauth_blend:%[0-9]+]]   = call i64 @llvm.ptrauth.blend(i64 [[continuation_fn_addr_int]], i64 55047)
 // CHECK-arm64e: [[continuation_fn_int:%[0-9]+]]      = ptrtoint ptr [[resume_intrinsic]] to i64
@@ -57,7 +57,7 @@ bb0:
 
 //   Arrive at the await_async_continuation point.
 // CHECK: [[suspend:%.*]] = call { ptr } (i32, ptr, ptr, ...) @llvm.coro.suspend.async.sl_p0s(i32 0, ptr [[resume_intrinsic]], ptr @__swift_async_resume_project_context, ptr @__swift_continuation_await_point, ptr [[cont_context]])
-// CHECK:   [[result_addr_addr:%.*]] = getelementptr inbounds %swift.continuation_context, ptr [[cont_context]], i32 0, i32 4
+// CHECK:   [[result_addr_addr:%.*]] = getelementptr inbounds{{.*}} %swift.continuation_context, ptr [[cont_context]], i32 0, i32 4
 // CHECK:   [[result_addr:%.*]] = load ptr, ptr [[result_addr_addr]]
 // CHECK:   [[result_value:%.*]] = load i32, ptr [[result_addr]]
 // CHECK:   br label %[[result_bb:[0-9]+]]
diff --git a/test/IRGen/async/hop_to_executor.sil b/test/IRGen/async/hop_to_executor.sil
index 421c04f0c3b7d..ca3f66b448aa0 100644
--- a/test/IRGen/async/hop_to_executor.sil
+++ b/test/IRGen/async/hop_to_executor.sil
@@ -2,9 +2,9 @@
 
 // REQUIRES: concurrency
 
-// WASI does not support the mandatory tail call, and needs to take the same
+// Wasm does not support the mandatory tail call, and needs to take the same
 // path as CHECK-WIN, but will currently go down CHECK-SYSV, failing the test.
-// XFAIL: OS=wasi
+// XFAIL: CPU=wasm32
 
 sil_stage canonical
 
@@ -20,7 +20,7 @@ import _Concurrency
 // CHECK: [[RESUME_CTX:%[0-9]+]] = call ptr @__swift_async_resume_get_context(
 // CHECK: store ptr [[RESUME_CTX]], ptr [[CTX_ADDR]]
 // CHECK: [[CTX:%[0-9+]+]] = load ptr, ptr [[CTX_ADDR]]
-// CHECK: [[CONT_ADDR:%[0-9]+]] = getelementptr inbounds <{ ptr, ptr }>, ptr [[CTX]], i32 0, i32 1
+// CHECK: [[CONT_ADDR:%[0-9]+]] = getelementptr inbounds{{.*}} <{ ptr, ptr }>, ptr [[CTX]], i32 0, i32 1
 // CHECK: [[RET_CONTINUATION:%.*]] = load ptr, ptr [[CONT_ADDR]]
 // CHECK-arm64e:  [[T0:%.*]] = ptrtoint ptr [[RET_CONTINUATION]] to i64
 // CHECK-arm64e:  [[T1:%.*]] = call i64 @llvm.ptrauth.auth(i64 [[T0]]
diff --git a/test/IRGen/async_dynamic_replacement.swift b/test/IRGen/async_dynamic_replacement.swift
index bef67f42375f3..f87a26aaadc6a 100644
--- a/test/IRGen/async_dynamic_replacement.swift
+++ b/test/IRGen/async_dynamic_replacement.swift
@@ -26,7 +26,7 @@ public func calls_number() async -> Int {
 
 // CHECK-LABEL: define {{.*}}swifttailcc void @"$s25async_dynamic_replacement32indirectReturnDynamicReplaceableSi_S6ityYaKF"(ptr {{.*}}%0, ptr swiftasync %1)
 // CHECK: forward_to_replaced:
-// CHECK: musttail call swifttailcc void {{.*}}(ptr noalias nocapture %0, ptr swiftasync {{.*}})
+// CHECK: musttail call swifttailcc void {{.*}}(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync {{.*}})
 public dynamic func indirectReturnDynamicReplaceable() async throws -> (Int, Int, Int, Int, Int, Int, Int) {
     return (0, 0, 0, 0, 0, 0, 0)
 }
diff --git a/test/IRGen/availability_custom_domains.swift b/test/IRGen/availability_custom_domains.swift
index 8952c4cd6111a..33b6fbbf08a24 100644
--- a/test/IRGen/availability_custom_domains.swift
+++ b/test/IRGen/availability_custom_domains.swift
@@ -1,12 +1,14 @@
 // RUN: %target-swift-emit-irgen -module-name Test %s -verify \
 // RUN:   -enable-experimental-feature CustomAvailability \
 // RUN:   -define-enabled-availability-domain EnabledDomain \
+// RUN:   -define-always-enabled-availability-domain AlwaysEnabledDomain \
 // RUN:   -define-disabled-availability-domain DisabledDomain \
 // RUN:   -Onone | %FileCheck %s --check-prefixes=CHECK
 
 // RUN: %target-swift-emit-irgen -module-name Test %s -verify \
 // RUN:   -enable-experimental-feature CustomAvailability \
 // RUN:   -define-enabled-availability-domain EnabledDomain \
+// RUN:   -define-always-enabled-availability-domain AlwaysEnabledDomain \
 // RUN:   -define-disabled-availability-domain DisabledDomain \
 // RUN:   -O | %FileCheck %s --check-prefixes=CHECK
 
@@ -18,36 +20,68 @@ public func always()
 @_silgen_name("never")
 public func never()
 
+// CHECK-LABEL: define {{.*}}swiftcc void @"$s4Test24ifAvailableEnabledDomainyyF"()
+// CHECK: call swiftcc void @always()
 // CHECK-NOT: call swiftcc void @never()
+public func ifAvailableEnabledDomain() {
+  if #available(EnabledDomain) {
+    always()
+  } else {
+    never()
+  }
+}
 
+// CHECK-LABEL: define {{.*}}swiftcc void @"$s4Test30ifAvailableAlwaysEnabledDomainyyF"()
 // CHECK: call swiftcc void @always()
 // CHECK-NOT: call swiftcc void @never()
-if #available(EnabledDomain) {
-  always()
-} else {
-  never()
+public func ifAvailableAlwaysEnabledDomain() {
+  if #available(AlwaysEnabledDomain) {
+    always()
+  } else {
+    never()
+  }
 }
 
-// CHECK: call swiftcc void @always()
+// CHECK-LABEL: define {{.*}}swiftcc void @"$s4Test25ifAvailableDisabledDomainyyF"()
 // CHECK-NOT: call swiftcc void @never()
-if #available(DisabledDomain) {
-  never()
-} else {
-  always()
+// CHECK: call swiftcc void @always()
+public func ifAvailableDisabledDomain() {
+  if #available(DisabledDomain) {
+    never()
+  } else {
+    always()
+  }
 }
 
+// CHECK-LABEL: define {{.*}}swiftcc void @"$s4Test26ifUnavailableEnabledDomainyyF"()
+// CHECK-NOT: call swiftcc void @never()
 // CHECK: call swiftcc void @always()
+public func ifUnavailableEnabledDomain() {
+  if #unavailable(EnabledDomain) {
+    never()
+  } else {
+    always()
+  }
+}
+
+// CHECK-LABEL: define {{.*}}swiftcc void @"$s4Test32ifUnavailableAlwaysEnabledDomainyyF"()
 // CHECK-NOT: call swiftcc void @never()
-if #unavailable(EnabledDomain) {
-  never()
-} else {
-  always()
+// CHECK: call swiftcc void @always()
+public func ifUnavailableAlwaysEnabledDomain() {
+  if #unavailable(EnabledDomain) {
+    never()
+  } else {
+    always()
+  }
 }
 
+// CHECK-LABEL: define {{.*}}swiftcc void @"$s4Test27ifUnavailableDisabledDomainyyF"()
 // CHECK: call swiftcc void @always()
 // CHECK-NOT: call swiftcc void @never()
-if #unavailable(DisabledDomain) {
-  always()
-} else {
-  never()
+public func ifUnavailableDisabledDomain() {
+  if #unavailable(DisabledDomain) {
+    always()
+  } else {
+    never()
+  }
 }
diff --git a/test/IRGen/availability_custom_domains_clang.swift b/test/IRGen/availability_custom_domains_clang.swift
new file mode 100644
index 0000000000000..c0a79478b1865
--- /dev/null
+++ b/test/IRGen/availability_custom_domains_clang.swift
@@ -0,0 +1,61 @@
+// RUN: %target-swift-emit-irgen -module-name Test %s -verify \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-bridging-header %S/Inputs/AvailabilityDomains.h \
+// RUN:   -Onone | %FileCheck %s --check-prefixes=CHECK,CHECK-O-NONE
+
+// RUN: %target-swift-emit-irgen -module-name Test %s -verify \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-bridging-header %S/Inputs/AvailabilityDomains.h \
+// RUN:   -O | %FileCheck %s --check-prefixes=CHECK,CHECK-O
+
+// REQUIRES: swift_feature_CustomAvailability
+
+// CHECK-LABEL: define {{.*}}swiftcc void @"$s4Test24ifAvailableEnabledDomainyyF"()
+// CHECK: call void @available_in_enabled_domain()
+// CHECK-NOT: call void @unavailable_in_enabled_domain()
+public func ifAvailableEnabledDomain() {
+  if #available(EnabledDomain) {
+    available_in_enabled_domain()
+  } else {
+    unavailable_in_enabled_domain()
+  }
+}
+
+// CHECK-LABEL: define {{.*}}swiftcc void @"$s4Test25ifAvailableDisabledDomainyyF"()
+// CHECK-NOT: call void @available_in_disabled_domain()
+// CHECK: call void @unavailable_in_disabled_domain()
+public func ifAvailableDisabledDomain() {
+  if #available(DisabledDomain) {
+    available_in_disabled_domain()
+  } else {
+    unavailable_in_disabled_domain()
+  }
+}
+
+// CHECK-LABEL:   define {{.*}}swiftcc void @"$s4Test24ifAvailableDynamicDomainyyF"()
+// CHECK:         entry:
+// CHECK-O-NONE:    [[QUERY_RESULT:%.*]] = call swiftcc i1 @"$sSC33__swift_DynamicDomain_isAvailableBi1_yF"()
+// CHECK-O:         [[QUERY_RESULT:%.*]] = call {{.*}}i1 @__DynamicDomain_isAvailable()
+// CHECK:           br i1 [[QUERY_RESULT]], label %[[TRUE_LABEL:.*]], label %[[FALSE_LABEL:.*]]
+// CHECK:         [[TRUE_LABEL]]:
+// CHECK:           call void @available_in_dynamic_domain()
+// CHECK:         [[FALSE_LABEL]]:
+// CHECK:           call void @unavailable_in_dynamic_domain()
+public func ifAvailableDynamicDomain() {
+  if #available(DynamicDomain) {
+    available_in_dynamic_domain()
+  } else {
+    unavailable_in_dynamic_domain()
+  }
+}
+
+// CHECK-O-NONE-LABEL: define {{.*}}swiftcc i1 @"$sSC33__swift_DynamicDomain_isAvailableBi1_yF"()
+// CHECK-O-NONE:       entry:
+// CHECK-O-NONE:         [[CALL:%.*]] = call {{.*}}i1 @__DynamicDomain_isAvailable()
+// CHECK-O-NONE:         ret i1 [[CALL]]
+
+// CHECK-LABEL: define {{.*}}i1 @__DynamicDomain_isAvailable()
+// CHECK:       entry:
+// CHECK:         [[CALL:%.*]] = call i32 @dynamic_domain_pred{{(.ptrauth)?}}()
+// CHECK:         [[TOBOOL:%.*]] = icmp ne i32 [[CALL]], 0
+// CHECK:         ret i1 [[TOBOOL]]
diff --git a/test/IRGen/availability_custom_domains_maccatalyst_zippered.swift b/test/IRGen/availability_custom_domains_maccatalyst_zippered.swift
new file mode 100644
index 0000000000000..f88c81cacda76
--- /dev/null
+++ b/test/IRGen/availability_custom_domains_maccatalyst_zippered.swift
@@ -0,0 +1,68 @@
+// RUN: %target-swift-emit-irgen -module-name Test %s -verify \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -define-enabled-availability-domain EnabledDomain \
+// RUN:   -define-disabled-availability-domain DisabledDomain \
+// RUN:   -target %target-cpu-apple-macosx13 \
+// RUN:   -target-variant %target-cpu-apple-ios16-macabi \
+// RUN:   -Onone | %FileCheck %s --check-prefixes=CHECK
+
+// RUN: %target-swift-emit-irgen -module-name Test %s -verify \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -define-enabled-availability-domain EnabledDomain \
+// RUN:   -define-disabled-availability-domain DisabledDomain \
+// RUN:   -target %target-cpu-apple-macosx13 \
+// RUN:   -target-variant %target-cpu-apple-ios16-macabi \
+// RUN:   -O | %FileCheck %s --check-prefixes=CHECK
+
+// REQUIRES: OS=macosx || OS=maccatalyst
+// REQUIRES: swift_feature_CustomAvailability
+
+@_silgen_name("always")
+public func always()
+
+@_silgen_name("never")
+public func never()
+
+// CHECK-LABEL: define swiftcc void @"$s4Test24ifAvailableEnabledDomainyyF"()
+// CHECK: call swiftcc void @always()
+// CHECK-NOT: call swiftcc void @never()
+public func ifAvailableEnabledDomain() {
+  if #available(EnabledDomain) {
+    always()
+  } else {
+    never()
+  }
+}
+
+// CHECK-LABEL: define swiftcc void @"$s4Test25ifAvailableDisabledDomainyyF"()
+// CHECK-NOT: call swiftcc void @never()
+// CHECK: call swiftcc void @always()
+public func ifAvailableDisabledDomain() {
+  if #available(DisabledDomain) {
+    never()
+  } else {
+    always()
+  }
+}
+
+// CHECK-LABEL: define swiftcc void @"$s4Test26ifUnavailableEnabledDomainyyF"()
+// CHECK-NOT: call swiftcc void @never()
+// CHECK: call swiftcc void @always()
+public func ifUnavailableEnabledDomain() {
+  if #unavailable(EnabledDomain) {
+    never()
+  } else {
+    always()
+  }
+}
+
+// CHECK-LABEL: define swiftcc void @"$s4Test27ifUnavailableDisabledDomainyyF"()
+// CHECK: call swiftcc void @always()
+// CHECK-NOT: call swiftcc void @never()
+public func ifUnavailableDisabledDomain() {
+  if #unavailable(DisabledDomain) {
+    always()
+  } else {
+    never()
+  }
+}
diff --git a/test/IRGen/backward_deploy_nonisolated_nonsending_function_type.swift b/test/IRGen/backward_deploy_nonisolated_nonsending_function_type.swift
new file mode 100644
index 0000000000000..265146cf8b969
--- /dev/null
+++ b/test/IRGen/backward_deploy_nonisolated_nonsending_function_type.swift
@@ -0,0 +1,17 @@
+// RUN: %target-swift-frontend -target %target-cpu-apple-macos12 -emit-ir -o - -primary-file %s | %FileCheck %s
+// REQUIRES: concurrency
+// REQUIRES: OS=macosx
+
+func useGenericMetatype(_ type: Any.Type) { }
+
+// CHECK-LABEL: define hidden swiftcc void @"$s52backward_deploy_nonisolated_nonsending_function_type29testNonisolatedNonsendingTypeyyF"()
+func testNonisolatedNonsendingType() {
+  typealias Fn = nonisolated(nonsending) () async throws -> Int
+
+  // CHECK: call swiftcc %swift.metadata_response @"$sSiyYaKYCcMa"
+  // CHECK: call swiftcc void @"$s52backward_deploy_nonisolated_nonsending_function_type18useGenericMetatypeyyypXpF"
+  useGenericMetatype(Fn.self)
+}
+
+// CHECK-LABEL: define linkonce_odr hidden swiftcc %swift.metadata_response @"$sSiyYaKYCcMa"
+// CHECK: call ptr @swift_getExtendedFunctionTypeMetadata(i{{32|64}} 2768240640, {{i32|i64}} 0, ptr null, ptr null, ptr @"$sSiN"
diff --git a/test/IRGen/backward_deploy_span.swift b/test/IRGen/backward_deploy_span.swift
new file mode 100644
index 0000000000000..5c88a8e163ca3
--- /dev/null
+++ b/test/IRGen/backward_deploy_span.swift
@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend -target %target-cpu-apple-macos12 -emit-ir -o - -primary-file %s | %FileCheck %s
+// REQUIRES: OS=macosx
+
+func useGenericMetatype(_ type: any ~Escapable.Type) { }
+
+// CHECK-LABEL: define hidden swiftcc void @"$s20backward_deploy_span11testSpanIntyyF"()
+func testSpanInt() {
+  // CHECK: call swiftcc %swift.metadata_response @"$ss4SpanVySiGMa"
+  // CHECK: call swiftcc void @"$s20backward_deploy_span18useGenericMetatypeyyypRi0_s_XPXpF"
+  useGenericMetatype(Span<Int>.self)
+}
+
+// CHECK-LABEL: define linkonce_odr hidden swiftcc %swift.metadata_response @"$ss4SpanVySiGMa"
+// CHECK: call swiftcc %swift.metadata_response @"$ss4SpanVMa"({{i32|i64}} %0, ptr @"$sSiN")
diff --git a/test/IRGen/big_types.sil b/test/IRGen/big_types.sil
index b50b5d965824b..109c7c02c2e66 100644
--- a/test/IRGen/big_types.sil
+++ b/test/IRGen/big_types.sil
@@ -80,17 +80,14 @@ unwind:
 // CHECK-LABEL: sil @use_yield_big : $@convention(thin) () -> () {
 // CHECK:       bb0:
 // CHECK-NEXT:    [[TEMP:%.*]] = alloc_stack $BigStruct
-// CHECK-NEXT:    [[TEMP2:%.*]] = alloc_stack $BigStruct
 // CHECK-NEXT:    // function_ref
 // CHECK-NEXT:    [[CORO:%.*]] = function_ref @test_yield_big : $@yield_once @convention(thin) () -> @yields @in_guaranteed BigStruct
 // CHECK-NEXT:    ([[ADDR:%.*]], [[TOKEN:%.*]]) = begin_apply [[CORO]]()
 // CHECK-NEXT:   copy_addr [take] [[ADDR]] to [init] [[TEMP]] : $*BigStruct
-// CHECK-NEXT:   copy_addr [take] [[TEMP]] to [init] [[TEMP2]] : $*BigStruct
 // CHECK-NEXT:    // function_ref
 // CHECK-NEXT:    [[USE:%.*]] = function_ref @use_big_struct : $@convention(thin) (@in_guaranteed BigStruct) -> ()
-// CHECK-NEXT:    apply [[USE]]([[TEMP2]])
+// CHECK-NEXT:    apply [[USE]]([[TEMP]])
 // CHECK-NEXT:    [[RET:%.*]] = end_apply [[TOKEN]] as $()
-// CHECK-NEXT:    dealloc_stack [[TEMP2]] : $*BigStruct
 // CHECK-NEXT:    dealloc_stack [[TEMP]] : $*BigStruct
 // CHECK-NEXT:    return [[RET]] : $()
 sil @use_yield_big : $@convention(thin) () -> () {
diff --git a/test/IRGen/big_types_corner_cases.sil b/test/IRGen/big_types_corner_cases.sil
index 270cd16c66cf1..c8fe0c44d99f6 100644
--- a/test/IRGen/big_types_corner_cases.sil
+++ b/test/IRGen/big_types_corner_cases.sil
@@ -38,7 +38,7 @@ public struct BigBigStruct {
 }
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testBitfieldInBlock
-// CHECK:         call void {{%.*}}(ptr noalias nocapture sret({{.*}}) {{%.*}}, ptr {{%.*}}, ptr byval({{.*}}) align 8 {{%.*}})
+// CHECK:         call void {{%.*}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{%.*}}, ptr {{%.*}}, ptr byval({{.*}}) align 8 {{%.*}})
 sil @testBitfieldInBlock : $@convention(thin) (@owned @convention(block) (BitfieldOne) -> BitfieldOne, BitfieldOne) -> BitfieldOne  {
 entry(%b : $@convention(block) (BitfieldOne) -> BitfieldOne, %x : $BitfieldOne):
   %r = apply %b(%x) : $@convention(block) (BitfieldOne) -> BitfieldOne
@@ -46,7 +46,7 @@ entry(%b : $@convention(block) (BitfieldOne) -> BitfieldOne, %x : $BitfieldOne):
 }
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testTupleExtract
-// CHECK:         call void {{%.*}}(ptr noalias nocapture sret({{.*}}) {{%.*}}, ptr {{%.*}}, ptr byval({{.*}}) align 8 {{%.*}})
+// CHECK:         call void {{%.*}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{%.*}}, ptr {{%.*}}, ptr byval({{.*}}) align 8 {{%.*}})
 sil @testTupleExtract : $@convention(thin) (@owned (BitfieldOne, @convention(block) (BitfieldOne) -> BitfieldOne), BitfieldOne) -> BitfieldOne  {
 entry(%b : $(BitfieldOne, @convention(block) (BitfieldOne) -> (BitfieldOne)), %x : $BitfieldOne):
   %a = tuple_extract %b : $(BitfieldOne, @convention(block) (BitfieldOne) -> (BitfieldOne)), 1
@@ -54,9 +54,9 @@ entry(%b : $(BitfieldOne, @convention(block) (BitfieldOne) -> (BitfieldOne)), %x
   return %r : $BitfieldOne
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testBigTempStruct(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %Element)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testBigTempStruct(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %Element)
 // CHECK: [[ALLOC:%.*]] = alloca %T22big_types_corner_cases13BigTempStructV
-// CHECK: call swiftcc void @testBigTempStruct(ptr noalias nocapture sret({{.*}}) [[ALLOC]], ptr %1, ptr %Element)
+// CHECK: call swiftcc void @testBigTempStruct(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[ALLOC]], ptr %1, ptr %Element)
 // CHECK: ret void
 sil @testBigTempStruct : $@convention(method) <Element> (@guaranteed _ArrayBuffer<Element>) -> @owned BigTempStruct<Element> {
 bb0(%0 : $_ArrayBuffer<Element>):
@@ -66,9 +66,9 @@ bb0(%0 : $_ArrayBuffer<Element>):
   return %9 : $BigTempStruct<Element>
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testTryApply(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2, ptr swiftself %3, ptr noalias nocapture swifterror dereferenceable(8) %4)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testTryApply(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2, ptr swiftself %3, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %4)
 // CHECK: [[ALLOC:%.*]] = alloca %T22big_types_corner_cases9BigStructV
-// CHECK: call swiftcc void {{.*}}(ptr noalias nocapture sret({{.*}}) [[ALLOC]]
+// CHECK: call swiftcc void {{.*}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[ALLOC]]
 // CHECK: ret void
 sil @testTryApply : $@convention(thin)(() -> (@owned BigStruct, @error Error)) -> (@owned BigStruct, @error Error) {
 bb0(%0 : $() -> (@owned BigStruct, @error Error)):
@@ -82,8 +82,8 @@ bb2(%err : $Error):
   throw %err : $Error
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testFuncWithModBlockStorageApply(ptr nocapture dereferenceable({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}})
-// CHECK: call swiftcc void {{.*}}(ptr noalias nocapture dereferenceable({{.*}}) %1
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testFuncWithModBlockStorageApply(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}})
+// CHECK: call swiftcc void {{.*}}(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1
 // CHECK: ret void
 sil @testFuncWithModBlockStorageApply : $@convention(thin) (@inout_aliasable @block_storage @callee_owned (@owned BigStruct) -> (), BigStruct) -> () {
 // %0                                             // user: %5
@@ -109,7 +109,7 @@ sil public_external @c_return_func : $@convention(thin) () -> () -> @owned BigSt
 // CHECK: [[RET:%.*]] = insertvalue { ptr, ptr } { ptr @"$s17part_apply_calleeTA", ptr undef }, ptr
 // CHECK: ret { ptr, ptr } [[RET]]
 
-// CHECK-LABEL: define internal swiftcc void @"$s17part_apply_calleeTA"(ptr noalias nocapture sret({{.*}}) %0, i64 %1, ptr swiftself %2)
+// CHECK-LABEL: define internal swiftcc void @"$s17part_apply_calleeTA"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, i64 %1, ptr swiftself %2)
 // CHECK: ret void
 
 sil @part_apply_caller : $@convention(thin) () -> @owned @callee_owned (@owned Builtin.Int64) -> @owned BigStruct {
@@ -174,12 +174,12 @@ sil @get_optional_none : $@convention(method) <τ_0_0> (@thin Optional<τ_0_0>.T
 sil @short_circuit_operation : $@convention(thin) <τ_0_0> (@in Optional<τ_0_0>, @owned @callee_owned () -> (@out τ_0_0, @error Error)) -> (@out τ_0_0, @error Error)
 sil @autoclosure_partialapply : $@convention(thin) (@owned @callee_owned () -> (BigStruct, @error Error)) -> (@out BigStruct, @error Error)
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @closure(ptr noalias nocapture sret({{.*}}) %0, ptr %1)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @closure(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1)
 // CHECK-64: [[ALLOC1:%.*]] = alloca %T22big_types_corner_cases9BigStructV
 // CHECK-64: [[ALLOC2:%.*]] = alloca %T22big_types_corner_cases9BigStructV
 // CHECK-64: [[ALLOC3:%.*]] = alloca %T22big_types_corner_cases9BigStructVSg
 // CHECK-64: [[ALLOC4:%.*]] = alloca %T22big_types_corner_cases9BigStructVSg
-// CHECK-64: call swiftcc void @"$s22big_types_corner_cases8SuperSubC1fyyFAA9BigStructVycfU_AFyKXKfu_TA"(ptr noalias nocapture sret({{.*}}) [[ALLOC1]], ptr swiftself {{.*}}, ptr nocapture swifterror %swifterror)
+// CHECK-64: call swiftcc void @"$s22big_types_corner_cases8SuperSubC1fyyFAA9BigStructVycfU_AFyKXKfu_TA"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[ALLOC1]], ptr swiftself {{.*}}, ptr{{( nocapture)?}} swifterror{{( captures\(none\))?}} %swifterror)
 // CHECK: ret void
 sil @closure : $@convention(thin) (@owned SuperSub) -> BigStruct {
 bb0(%0 : $SuperSub):
@@ -218,7 +218,7 @@ sil @returnBigStruct : $@convention(thin) () -> @owned BigStruct
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @closureToConvert()
 // CHECK: entry:
 // CHECK:   [[ALLOC:%.*]] = alloca %T22big_types_corner_cases9BigStructV
-// CHECK:   call swiftcc void @returnBigStruct(ptr noalias nocapture sret({{.*}}) [[ALLOC]])
+// CHECK:   call swiftcc void @returnBigStruct(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[ALLOC]])
 // CHECK:   ret void
 // CHECK-LABEL: }
 sil @closureToConvert : $@convention(thin) () -> () {
@@ -246,11 +246,11 @@ bb0:
 
 sil @convertToThickHelper : $@convention(thin) (@owned BigStruct) -> ()
 
-// CHECK-LABAL: define {{.*}} swiftcc void @convertToThick(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABAL: define {{.*}} swiftcc void @convertToThick(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 // CHECK: entry:
 // CHECK:   [[ALLOC:%.*]] = alloca %T22big_types_corner_cases9BigStructV, align 4
 // CHECK:   call void @llvm.memcpy.p0.p0.i64
-// CHECK:   call swiftcc void @convertToThickHelper(ptr noalias nocapture dereferenceable({{.*}}) [[ALLOC]], ptr swiftself null)
+// CHECK:   call swiftcc void @convertToThickHelper(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) [[ALLOC]], ptr swiftself null)
 // CHECK:   ret void
 // CHECK-LABEL: }
 sil @convertToThick : $@convention(thin) (@in BigStruct) -> () {
diff --git a/test/IRGen/big_types_corner_cases.swift b/test/IRGen/big_types_corner_cases.swift
index d63789ac579ec..7ba25031f4ad2 100644
--- a/test/IRGen/big_types_corner_cases.swift
+++ b/test/IRGen/big_types_corner_cases.swift
@@ -46,7 +46,7 @@ let bigStructGlobalArray : [BigStruct] = [
   BigStruct()
 ]
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} internal swiftcc void @"$s22big_types_corner_cases21OptionalInoutFuncTypeC7executeyys5Error_pSgFyyXEfU_"(ptr nocapture dereferenceable({{.*}}) %0, ptr %1, ptr nocapture dereferenceable({{.*}})
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} internal swiftcc void @"$s22big_types_corner_cases21OptionalInoutFuncTypeC7executeyys5Error_pSgFyyXEfU_"(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, ptr %1, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}})
 // CHECK: call void @"$s22big_types_corner_cases9BigStructVSgs5Error_pSgIegng_SgWOe
 // CHECK: call void @"$s22big_types_corner_cases9BigStructVSgs5Error_pSgIegng_SgWOy
 // CHECK: ret void
@@ -66,9 +66,9 @@ public func f3_uses_f2() {
 }
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases10f3_uses_f2yyF"()
-// CHECK: call swiftcc void @"$s22big_types_corner_cases9BigStructVACycfC"(ptr noalias nocapture sret({{.*}})
+// CHECK: call swiftcc void @"$s22big_types_corner_cases9BigStructVACycfC"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}}
 // CHECK: call swiftcc { ptr, ptr } @"$s22big_types_corner_cases13f2_returns_f1AA9BigStructVADcyF"()
-// CHECK: call swiftcc void {{.*}}(ptr noalias nocapture sret({{.*}}) {{.*}}, ptr noalias nocapture dereferenceable({{.*}}) {{.*}}, ptr swiftself {{.*}})
+// CHECK: call swiftcc void {{.*}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{.*}}, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) {{.*}}, ptr swiftself {{.*}})
 // CHECK: ret void
 
 public func f4_tuple_use_of_f2() {
@@ -81,7 +81,7 @@ public func f4_tuple_use_of_f2() {
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases18f4_tuple_use_of_f2yyF"()
 // CHECK: [[TUPLE:%.*]] = call swiftcc { ptr, ptr } @"$s22big_types_corner_cases13f2_returns_f1AA9BigStructVADcyF"()
 // CHECK: [[TUPLE_EXTRACT:%.*]] = extractvalue { ptr, ptr } [[TUPLE]], 0
-// CHECK:  call swiftcc void [[TUPLE_EXTRACT]](ptr noalias nocapture sret({{.*}}) {{.*}}, ptr noalias nocapture dereferenceable({{.*}}) {{.*}}, ptr swiftself %{{.*}})
+// CHECK:  call swiftcc void [[TUPLE_EXTRACT]](ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{.*}}, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) {{.*}}, ptr swiftself %{{.*}})
 // CHECK: ret void
 
 public class BigClass {
@@ -95,8 +95,8 @@ public class BigClass {
   }
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} hidden swiftcc void @"$s22big_types_corner_cases8BigClassC03useE6Struct0aH0yAA0eH0V_tF"(ptr noalias nocapture dereferenceable({{.*}}) %0, ptr swiftself %1)
-// CHECK: call swiftcc void {{.*}}(ptr noalias nocapture dereferenceable({{.*}}) %0, ptr swiftself
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} hidden swiftcc void @"$s22big_types_corner_cases8BigClassC03useE6Struct0aH0yAA0eH0V_tF"(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, ptr swiftself %1)
+// CHECK: call swiftcc void {{.*}}(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, ptr swiftself
 // CHECK: ret void
 
 public struct MyStruct {
@@ -134,17 +134,17 @@ public func enumCallee(_ x: LargeEnum) {
     case .Empty2: break
   }
 }
-// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases10enumCalleeyyAA9LargeEnumOF"(ptr noalias nocapture dereferenceable({{.*}}) %0) #0 {
+// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases10enumCalleeyyAA9LargeEnumOF"(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) #0 {
 // CHECK-64: alloca %T22big_types_corner_cases9LargeEnumO05InnerF0O
 // CHECK-64: alloca %T22big_types_corner_cases9LargeEnumO
 // CHECK-64: $ss5print_9separator10terminatoryypd_S2StF
 // CHECK-64: ret void
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} internal swiftcc void @"$s22big_types_corner_cases8SuperSubC1fyyFAA9BigStructVycfU_"(ptr noalias nocapture sret({{.*}}) %0, ptr %1)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} internal swiftcc void @"$s22big_types_corner_cases8SuperSubC1fyyFAA9BigStructVycfU_"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1)
 // CHECK-64: [[ALLOC1:%.*]] = alloca %T22big_types_corner_cases9BigStructV
 // CHECK-64: [[ALLOC2:%.*]] = alloca %T22big_types_corner_cases9BigStructV
 // CHECK-64: [[ALLOC3:%.*]] = alloca %T22big_types_corner_cases9BigStructVSg
-// CHECK-64: call swiftcc void @"$s22big_types_corner_cases9SuperBaseC4boomAA9BigStructVyF"(ptr noalias nocapture sret({{.*}}) [[ALLOC1]], ptr swiftself {{.*}})
+// CHECK-64: call swiftcc void @"$s22big_types_corner_cases9SuperBaseC4boomAA9BigStructVyF"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[ALLOC1]], ptr swiftself {{.*}})
 // CHECK: ret void
 class SuperBase {
   func boom() -> BigStruct {
@@ -164,10 +164,10 @@ class SuperSub : SuperBase {
   }
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases10MUseStructV16superclassMirrorAA03BigF0VSgvg"(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture swiftself dereferenceable({{.*}}) %1)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases10MUseStructV16superclassMirrorAA03BigF0VSgvg"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{.*}}) %1)
 // CHECK: [[ALLOC:%.*]] = alloca %T22big_types_corner_cases9BigStructVSg
 // CHECK: [[LOAD:%.*]] = load ptr, ptr %.callInternalLet.data
-// CHECK: call swiftcc void %{{[0-9]+}}(ptr noalias nocapture sret({{.*}}) [[ALLOC]], ptr swiftself [[LOAD]])
+// CHECK: call swiftcc void %{{[0-9]+}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[ALLOC]], ptr swiftself [[LOAD]])
 // CHECK: ret void
 public struct MUseStruct {
   var x = BigStruct()
@@ -178,8 +178,8 @@ public struct MUseStruct {
   internal let callInternalLet: () -> BigStruct?
 }
 
-// CHECK-LABEL-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases18stringAndSubstringSS_s0G0VtyF"(ptr noalias sret({{.*}}) %0) #0 {
-// CHECK-LABEL-32: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases18stringAndSubstringSS_s0G0VtyF"(ptr noalias sret({{.*}}) %0) #0 {
+// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases18stringAndSubstringSS_SstyF"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0) #0 {
+// CHECK-32-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases18stringAndSubstringSS_SstyF"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0) #0 {
 // CHECK: alloca %TSs
 // CHECK: alloca %TSs
 // CHECK: ret void
@@ -296,9 +296,9 @@ public extension QueryHandler {
         body(query)
     }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_25query8ReturnedQyd___AA9BigStructVSgtqd___tAA0E0Rd__lF"(ptr noalias nocapture sret({{.*}}) %0, ptr noalias %1, ptr noalias %2, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias swiftself %3)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_25query8ReturnedQyd___AA9BigStructVSgtqd___tAA0E0Rd__lF"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias %1, ptr noalias %2, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias swiftself %3)
 // CHECK: [[ALLOC:%.*]] = alloca %T22big_types_corner_cases9BigStructVSg
-// CHECK: call swiftcc void {{.*}}(ptr noalias nocapture sret({{.*}}) [[ALLOC]], ptr noalias {{.*}}, ptr noalias {{.*}}, ptr swiftself {{.*}})
+// CHECK: call swiftcc void {{.*}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[ALLOC]], ptr noalias {{.*}}, ptr noalias {{.*}}, ptr swiftself {{.*}})
 // CHECK: ret void
     func forceHandle_2<Q: Query>(query: Q) -> (Q.Returned, BigStruct?) {
         guard let body = handle_2 as? (Q) -> (Q.Returned, BigStruct?) else {
@@ -307,11 +307,11 @@ public extension QueryHandler {
         return body(query)
     }
 
-// CHECK-LABEL-64: define{{( dllexport)?}}{{( protected)?}} swiftcc { i64, i64 } @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_35query8ReturnedQyd___SbAA9BigStructVcSgtqd___tAA0E0Rd__lF"(ptr noalias %0, ptr noalias nocapture %1, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias nocapture swiftself %2)
+// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { i64, i64 } @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_35query8ReturnedQyd___SbAA9BigStructVcSgtqd___tAA0E0Rd__lF"(ptr noalias %0, ptr noalias %1, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias swiftself %2)
 // CHECK-64: {{.*}} = call swiftcc { i64, i64 } {{.*}}(ptr noalias {{.*}}, ptr noalias {{.*}}, ptr swiftself {{.*}})
 // CHECK-64: ret { i64, i64 }
 
-// CHECK-LABEL-32: define{{( dllexport)?}}{{( protected)?}} swiftcc { i32, i32} @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_35query8ReturnedQyd___SbAA9BigStructVcSgtqd___tAA0E0Rd__lF"(ptr noalias %0, ptr noalias nocapture %1, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias nocapture swiftself %2)
+// CHECK-32-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { i32, i32 } @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_35query8ReturnedQyd___SbAA9BigStructVcSgtqd___tAA0E0Rd__lF"(ptr noalias %0, ptr noalias %1, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias swiftself %2)
 // CHECK-32: {{.*}} = call swiftcc { i32, i32 } {{.*}}(ptr noalias {{.*}}, ptr noalias {{.*}}, ptr swiftself {{.*}})
 // CHECK-32: ret { i32, i32 }
     func forceHandle_3<Q: Query>(query: Q) -> (Q.Returned, Filter?) {
@@ -321,12 +321,12 @@ public extension QueryHandler {
         return body(query)
     }
 
-// CHECK-LABEL-64: define{{( dllexport)?}}{{( protected)?}} swiftcc { i64, i64 } @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_45query8ReturnedQyd___SbAA9BigStructVcSgtqd___tKAA0E0Rd__lF"(ptr noalias %0, ptr noalias nocapture %1, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias nocapture swiftself %2, ptr swifterror %3)
-// CHECK-64: {{.*}} = call swiftcc { i64, i64 } {{.*}}(ptr noalias {{.*}}, ptr noalias {{.*}}, ptr swiftself {{.*}}, ptr noalias nocapture swifterror {{.*}})
+// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { i64, i64 } @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_45query8ReturnedQyd___SbAA9BigStructVcSgtqd___tKAA0E0Rd__lF"(ptr noalias %0, ptr noalias %1, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.*}}) %3)
+// CHECK-64: {{.*}} = call swiftcc { i64, i64 } {{.*}}(ptr noalias {{.*}}, ptr noalias {{.*}}, ptr swiftself {{.*}}, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} {{.*}})
 // CHECK-64: ret { i64, i64 }
 
-// CHECK-LABEL-32: define{{( dllexport)?}}{{( protected)?}} swiftcc { i32, i32} @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_45query8ReturnedQyd___SbAA9BigStructVcSgtqd___tKAA0E0Rd__lF"(ptr noalias %0, ptr noalias nocapture %1, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias nocapture swiftself %2, ptr swifterror %3)
-// CHECK-32: {{.*}} = call swiftcc { i32, i32 } {{.*}}(ptr noalias {{.*}}, ptr noalias {{.*}}, ptr swiftself {{.*}}, ptr noalias nocapture {{.*}})
+// CHECK-32-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { i32, i32 } @"$s22big_types_corner_cases12QueryHandlerPAAE13forceHandle_45query8ReturnedQyd___SbAA9BigStructVcSgtqd___tKAA0E0Rd__lF"(ptr noalias %0, ptr noalias %1, ptr{{.*}}, ptr{{.*}}, ptr {{.*}}.QueryHandler, ptr {{.*}}.Query, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.*}}) %3)
+// CHECK-32: {{.*}} = call swiftcc { i32, i32 } {{.*}}(ptr noalias {{.*}}, ptr noalias {{.*}}, ptr swiftself {{.*}}, ptr noalias{{( nocapture)?}}{{.*}}{{( captures\(none\))?}} {{.*}})
 // CHECK-32: ret { i32, i32 }
     func forceHandle_4<Q: Query>(query: Q) throws -> (Q.Returned, Filter?) {
         guard let body = handle_4 as? (Q) throws -> (Q.Returned, Filter?) else {
diff --git a/test/IRGen/big_types_corner_cases_tiny.swift b/test/IRGen/big_types_corner_cases_tiny.swift
index 3907e86260804..8dd69dc3dc8e4 100644
--- a/test/IRGen/big_types_corner_cases_tiny.swift
+++ b/test/IRGen/big_types_corner_cases_tiny.swift
@@ -6,6 +6,6 @@
 
 // CHECK-LABEL: define internal void @{{.*}}WZ
 // CHECK: [[ALLOC:%.*]] = alloca %T27big_types_corner_cases_tiny30LoadableStructWithBiggerStringV
-// CHECK: call swiftcc void {{.*}}(ptr noalias nocapture sret({{.*}}) [[ALLOC]]
+// CHECK: call swiftcc void {{.*}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[ALLOC]]
 let model = ClassWithLoadableStructWithBiggerString().f()
 
diff --git a/test/IRGen/big_types_tests.sil b/test/IRGen/big_types_tests.sil
index acd9a7161a75b..3e32c543a147d 100644
--- a/test/IRGen/big_types_tests.sil
+++ b/test/IRGen/big_types_tests.sil
@@ -19,7 +19,7 @@ public struct BigStruct {
   var i8 : Int32 = 8
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testDestroyValue(ptr noalias nocapture dereferenceable({{.*}}) #0 {
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testDestroyValue(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) #0 {
 // CHECK-NEXT: entry
 // CHECK-NEXT: ret void
 sil @testDestroyValue : $@convention(thin) (@owned BigStruct) -> ()  {
diff --git a/test/IRGen/bitcast.sil b/test/IRGen/bitcast.sil
index ec89dbc965c87..093886d564e2f 100644
--- a/test/IRGen/bitcast.sil
+++ b/test/IRGen/bitcast.sil
@@ -19,7 +19,7 @@ protocol CP: class {}
 // CHECK-i386-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @bitcast_trivial(ptr %0) {{.*}} {
 // CHECK-i386:         [[BUF:%.*]] = alloca ptr, align 4
 // CHECK-i386:         store ptr %0, ptr [[BUF]]
-// CHECK-i386:         [[VALUE_BUF:%.*]] = getelementptr inbounds %TSi, ptr [[BUF]], i32 0, i32 0
+// CHECK-i386:         [[VALUE_BUF:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[BUF]], i32 0, i32 0
 // CHECK-i386:         [[VALUE:%.*]] = load i32, ptr [[VALUE_BUF]], align 4
 // CHECK-i386:         ret i32 [[VALUE]]
 // CHECK-i386:       }
@@ -27,7 +27,7 @@ protocol CP: class {}
 // CHECK-x86_64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i64 @bitcast_trivial(ptr %0) {{.*}} {
 // CHECK-x86_64:         [[BUF:%.*]] = alloca ptr, align 8
 // CHECK-x86_64:         store ptr %0, ptr [[BUF]]
-// CHECK-x86_64:         [[VALUE_BUF:%.*]] = getelementptr inbounds %TSi, ptr [[BUF]], i32 0, i32 0
+// CHECK-x86_64:         [[VALUE_BUF:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[BUF]], i32 0, i32 0
 // CHECK-x86_64:         [[VALUE:%.*]] = load i64, ptr [[VALUE_BUF]], align 8
 // CHECK-x86_64:         ret i64 [[VALUE]]
 // CHECK-x86_64:       }
@@ -40,11 +40,9 @@ entry(%c : $C):
 
 // CHECK-x86_64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { i64, i8 } @bitcast_trivial_optional(i64 %0, i8 %1) {{.*}} {
 // CHECK-x86_64-NEXT:  entry:
-// CHECK-x86_64-NEXT:   %2 = trunc i8 %1 to i1
-// CHECK-x86_64-NEXT:   %3 = zext i1 %2 to i8
-// CHECK-x86_64-NEXT:   %4 = insertvalue { i64, i8 } undef, i64 %0, 0
-// CHECK-x86_64-NEXT:   %5 = insertvalue { i64, i8 } %4, i8 %3, 1
-// CHECK-x86_64-NEXT:   ret { i64, i8 } %5
+// CHECK-x86_64-NEXT:   %2 = insertvalue { i64, i8 } undef, i64 %0, 0
+// CHECK-x86_64-NEXT:   %3 = insertvalue { i64, i8 } %2, i8 %1, 1
+// CHECK-x86_64-NEXT:   ret { i64, i8 } %3
 
 sil @bitcast_trivial_optional: $@convention(thin) (Optional<Int>) -> Optional<Int> {
 entry(%c : $Optional<Int>):
@@ -90,7 +88,7 @@ bb0(%0 : $Optional<C>):
 //   A bunch of GEPs happen here to get from Int to int.
 // CHECK-x86_64:      store i64 %{{.*}}, ptr %bitcast.elt._value, align 8
 // CHECK-x86_64:      store i64 %{{.*}}, ptr %bitcast.elt1._value, align 8
-// CHECK-x86_64-NEXT: [[VAL:%.*]] = getelementptr inbounds %TSi, ptr %bitcast, i32 0, i32 0
+// CHECK-x86_64-NEXT: [[VAL:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr %bitcast, i32 0, i32 0
 // CHECK-x86_64-NEXT: [[RESULT:%.*]] = load i64, ptr [[VAL]], align 8
 // CHECK-x86_64:      ret i64 [[RESULT]]
 // CHECK-x86_64-NEXT: }
diff --git a/test/IRGen/bitwise_copyable_resilient.swift b/test/IRGen/bitwise_copyable_resilient.swift
index ea960af42f822..977cfb093bd3f 100644
--- a/test/IRGen/bitwise_copyable_resilient.swift
+++ b/test/IRGen/bitwise_copyable_resilient.swift
@@ -10,7 +10,7 @@
 
 // RUN: %target-swift-frontend                           \
 // RUN:     %t/DownstreamDiagnostics.swift               \
-// RUN:     -typecheck -verify                           \
+// RUN:     -typecheck -verify -verify-ignore-unrelated                           \
 // RUN:     -debug-diagnostic-names                      \
 // RUN:     -I %t
 
diff --git a/test/IRGen/borrow_accessor.swift b/test/IRGen/borrow_accessor.swift
new file mode 100644
index 0000000000000..9efd55f5ab085
--- /dev/null
+++ b/test/IRGen/borrow_accessor.swift
@@ -0,0 +1,394 @@
+// RUN:%target-swift-frontend -emit-irgen %s -verify  -enable-experimental-feature BorrowAndMutateAccessors | %FileCheck %s
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+// REQUIRES: OS=macosx
+
+public class Klass {
+  var id: Int = 0
+}
+
+func getKlass() -> Klass {
+  return Klass()
+}
+
+@inline(never)
+func use(_ k: Klass) {
+  print(k.id)
+}
+
+@inline(never)
+func use(_ tuple: (Klass, Klass, Klass, Klass, Klass, Klass, Klass, Klass)) {
+  print(tuple.4.id)
+}
+
+public struct NC : ~Copyable {
+  var id: Int = 0
+}
+
+@inline(never)
+func use(_ t: borrowing NC) {
+  print(t.id)
+}
+
+public struct S {
+  var _k: Klass
+
+  var k: Klass {
+    borrow {
+      return _k
+    }
+  }
+}
+
+public struct Wrapper {
+  var _k: Klass
+  var _s: S
+
+  var s: S {
+    borrow {
+      return _s
+    }
+  }
+
+  var k: Klass {
+    borrow {
+      return _k
+    }
+  }
+
+  var nested1: Klass {
+    borrow {
+      return _s.k
+    }
+  }
+
+  var nested2: Klass {
+    borrow {
+      return k
+    }
+  }
+
+  subscript(index: Int) -> Klass {
+    borrow {
+      return _k
+    }
+  }
+
+  var nested_subscript: Klass {
+    borrow {
+      return self[0]
+    }
+  }
+}
+
+public struct SimpleWrapper<T> {
+  var _prop: T
+
+  var prop: T {
+    borrow {
+      return _prop
+    }
+  }
+}
+
+public struct GenWrapper<T> {
+  var _prop: T
+  var _s: SimpleWrapper<T>
+  var _k: Klass
+
+  public var prop: T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var nested1: T {
+    borrow {
+      return _s.prop
+    }
+  }
+
+  var nested2: T {
+    borrow {
+      return prop
+    }
+  }
+
+  var k: Klass {
+    borrow {
+      return _k
+    }
+  }
+
+  subscript(index: Int) -> T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var nested_subscript: T {
+    borrow {
+      return self[0]
+    }
+  }
+}
+
+public struct SimpleNCWrapper<T : ~Copyable> : ~Copyable {
+  var _prop: T
+
+  var prop: T {
+    borrow {
+      return _prop
+    }
+  }
+}
+
+public struct GenNCWrapper<T : ~Copyable> : ~Copyable {
+  var _prop: T
+  var _s: SimpleNCWrapper<T>
+
+  public var prop: T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var nested1: T {
+    borrow {
+      return _s.prop
+    }
+  }
+
+  var nested2: T {
+    borrow {
+      return prop
+    }
+  }
+
+  subscript(index: Int) -> T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var nested_subscript: T {
+    borrow {
+      return self[0]
+    }
+  }
+}
+
+public struct NCS: ~Copyable {
+  var _nc: NC
+
+  var nc: NC {
+    borrow {
+      return _nc
+    }
+  }
+}
+
+public struct NCWrapper: ~Copyable {
+  var _nc: NC
+  var _s: NCS
+
+  var nc: NC {
+    borrow {
+      return _nc
+    }
+  }
+  var nested1: NC {
+    borrow {
+      return _s.nc
+    }
+  }
+
+  var nested2: NC {
+    borrow {
+      return nc
+    }
+  }
+
+  subscript(index: Int) -> NC {
+    borrow {
+      return _nc
+    }
+  }
+
+  var nested_subscript: NC {
+    borrow {
+      return self[0]
+    }
+  }
+}
+
+public struct LargeStruct {
+  var _k: Klass
+  var _t: (Int, Int, Int, Int, Int, Int, Int, Int)
+  var _tuple: (Klass, Klass, Klass, Klass, Klass, Klass, Klass, Klass)
+
+  var borrowKlass: Klass {
+    borrow {
+      return _k
+    }
+  }
+  var borrowTuple: (Klass, Klass, Klass, Klass, Klass, Klass, Klass, Klass) {
+    borrow {
+      return _tuple
+    }
+  }
+}
+
+func test() {
+  let w1 = Wrapper(_k: Klass(), _s: S(_k: Klass()))
+  use(w1.k)
+  use(w1.s.k)
+  use(w1.nested1)
+  use(w1.nested2)
+
+  let w2 = GenWrapper(_prop: Klass(), _s: SimpleWrapper(_prop: Klass()), _k: Klass())
+  use(w2.prop)
+  use(w2.nested1)
+  use(w2.nested2)
+
+  let w3 = GenNCWrapper(_prop: NC(), _s: SimpleNCWrapper(_prop: NC()))
+  use(w3.prop)
+  use(w3.nested1)
+  use(w3.nested2)
+
+  let l = LargeStruct(_k: Klass(), _t: (1,2,3,4,5,6,7,8), _tuple: (Klass(), Klass(), Klass(), Klass(), Klass(), Klass(), Klass(), Klass()))
+  use(l.borrowKlass)
+  use(l.borrowTuple)
+}
+
+// IRGen explodes the struct parameter and returns the specified field
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor7WrapperV1kAA5KlassCvb"(ptr [[REG0:%.*]], ptr [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   ret ptr [[REG0]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor7WrapperV7nested1AA5KlassCvb"(ptr [[REG0:%.*]], ptr [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc ptr @"$s15borrow_accessor1SV1kAA5KlassCvb"(ptr [[REG1]])
+// CHECK:   ret ptr [[REG2]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor7WrapperV7nested2AA5KlassCvb"(ptr [[REG0:%.*]], ptr [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc ptr @"$s15borrow_accessor7WrapperV1kAA5KlassCvb"(ptr [[REG0]], ptr [[REG1]])
+// CHECK:   ret ptr [[REG2]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor7WrapperVyAA5KlassCSicib"(i64 [[REG0:%.*]], ptr [[REG1:%.*]], ptr [[REG2:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   ret ptr [[REG1]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor7WrapperV16nested_subscriptAA5KlassCvb"(ptr [[REG0:%.*]], ptr [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc ptr @"$s15borrow_accessor7WrapperVyAA5KlassCSicib"(i64 0, ptr [[REG0]], ptr [[REG1]])
+// CHECK:   ret ptr [[REG2]]
+// CHECK: }
+
+// CHECK: define swiftcc ptr @"$s15borrow_accessor10GenWrapperV4propxvb"(ptr %"GenWrapper<T>", ptr noalias swiftself [[REG0:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   ret ptr [[REG0]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor10GenWrapperV7nested1xvb"(ptr %"GenWrapper<T>", ptr noalias swiftself [[REG0:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = getelementptr inbounds i32, ptr %"GenWrapper<T>", i64 7
+// CHECK:   [[REG3:%.*]] = load i32, ptr [[REG2]], align 8
+// CHECK:   [[REG4:%.*]] = getelementptr inbounds i8, ptr [[REG0]], i32 [[REG3]]
+// CHECK:   [[REG5:%.*]] = call swiftcc %swift.metadata_response @"$s15borrow_accessor13SimpleWrapperVMa"(i64 0, ptr %T)
+// CHECK:   [[REG6:%.*]] = extractvalue %swift.metadata_response [[REG5]], 0
+// CHECK:   [[REG7:%.*]] = call swiftcc ptr @"$s15borrow_accessor13SimpleWrapperV4propxvb"(ptr [[REG6]], ptr noalias swiftself [[REG4]])
+// CHECK:   ret ptr [[REG7]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor10GenWrapperV7nested2xvb"(ptr %"GenWrapper<T>", ptr noalias swiftself [[REG0:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc ptr @"$s15borrow_accessor10GenWrapperV4propxvb"(ptr %"GenWrapper<T>", ptr noalias swiftself [[REG0]])
+// CHECK:   ret ptr [[REG2]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor10GenWrapperV1kAA5KlassCvb"(ptr %"GenWrapper<T>", ptr noalias swiftself [[REG0:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = getelementptr inbounds i32, ptr %"GenWrapper<T>", i64 8
+// CHECK:   [[REG3:%.*]] = load i32, ptr [[REG2]], align 8
+// CHECK:   [[REG4:%.*]] = getelementptr inbounds i8, ptr [[REG0]], i32 [[REG3]]
+// CHECK:   [[REG5:%.*]] = load ptr, ptr [[REG4]], align 8
+// CHECK:   ret ptr [[REG5]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor10GenWrapperVyxSicib"(i64 [[REG0:%.*]], ptr %"GenWrapper<T>", ptr noalias swiftself [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   ret ptr [[REG1]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor10GenWrapperV16nested_subscriptxvb"(ptr %"GenWrapper<T>", ptr noalias swiftself [[REG0:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc ptr @"$s15borrow_accessor10GenWrapperVyxSicib"(i64 0, ptr %"GenWrapper<T>", ptr noalias swiftself [[REG0]])
+// CHECK:   ret ptr [[REG2]]
+// CHECK: }
+
+// CHECK: define swiftcc ptr @"$s15borrow_accessor12GenNCWrapperVAARi_zrlE4propxvb"(ptr %"GenNCWrapper<T>", ptr noalias swiftself [[REG0:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   ret ptr [[REG0]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor12GenNCWrapperVAARi_zrlE7nested1xvb"(ptr %"GenNCWrapper<T>", ptr noalias swiftself [[REG0:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = getelementptr inbounds i32, ptr %"GenNCWrapper<T>", i64 7
+// CHECK:   [[REG3:%.*]] = load i32, ptr [[REG2]], align 8
+// CHECK:   [[REG4:%.*]] = getelementptr inbounds i8, ptr [[REG0]], i32 [[REG3]]
+// CHECK:   [[REG5:%.*]] = call swiftcc %swift.metadata_response @"$s15borrow_accessor15SimpleNCWrapperVMa"(i64 0, ptr %T)
+// CHECK:   [[REG6:%.*]] = extractvalue %swift.metadata_response [[REG5]], 0
+// CHECK:   [[REG7:%.*]] = call swiftcc ptr @"$s15borrow_accessor15SimpleNCWrapperVAARi_zrlE4propxvb"(ptr [[REG6]], ptr noalias swiftself [[REG4]])
+// CHECK:   ret ptr [[REG7]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor12GenNCWrapperVAARi_zrlE7nested2xvb"(ptr %"GenNCWrapper<T>", ptr noalias swiftself [[REG0:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc ptr @"$s15borrow_accessor12GenNCWrapperVAARi_zrlE4propxvb"(ptr %"GenNCWrapper<T>", ptr noalias swiftself [[REG0]])
+// CHECK:   ret ptr [[REG2]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor12GenNCWrapperVAARi_zrlEyxSicib"(i64 [[REG0:%.*]], ptr %"GenNCWrapper<T>", ptr noalias swiftself [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   ret ptr [[REG1]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc ptr @"$s15borrow_accessor12GenNCWrapperVAARi_zrlE16nested_subscriptxvb"(ptr %"GenNCWrapper<T>", ptr noalias swiftself [[REG0:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc ptr @"$s15borrow_accessor12GenNCWrapperVAARi_zrlEyxSicib"(i64 0, ptr %"GenNCWrapper<T>", ptr noalias swiftself [[REG0]])
+// CHECK:   ret ptr [[REG2]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc i64 @"$s15borrow_accessor9NCWrapperV2ncAA2NCVvb"(i64 [[REG0:%.*]], i64 [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   ret i64 [[REG0]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc i64 @"$s15borrow_accessor9NCWrapperV7nested1AA2NCVvb"(i64 [[REG0:%.*]], i64 [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc i64 @"$s15borrow_accessor3NCSV2ncAA2NCVvb"(i64 [[REG1]])
+// CHECK:   ret i64 [[REG2]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc i64 @"$s15borrow_accessor9NCWrapperV7nested2AA2NCVvb"(i64 [[REG0:%.*]], i64 [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc i64 @"$s15borrow_accessor9NCWrapperV2ncAA2NCVvb"(i64 [[REG0]], i64 [[REG1]])
+// CHECK:   ret i64 [[REG2]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc i64 @"$s15borrow_accessor9NCWrapperVyAA2NCVSicib"(i64 [[REG0]], i64 [[REG1]], i64 [[REG2]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   ret i64 [[REG1]]
+// CHECK: }
+
+// CHECK: define hidden swiftcc i64 @"$s15borrow_accessor9NCWrapperV16nested_subscriptAA2NCVvb"(i64 [[REG0:%.*]], i64 [[REG1:%.*]]) {{.*}} {
+// CHECK: entry:
+// CHECK:   [[REG2:%.*]] = call swiftcc i64 @"$s15borrow_accessor9NCWrapperVyAA2NCVSicib"(i64 0, i64 [[REG0]], i64 [[REG1]])
+// CHECK:   ret i64 [[REG2]]
+// CHECK: }
diff --git a/test/IRGen/borrow_accessor_large.swift b/test/IRGen/borrow_accessor_large.swift
new file mode 100644
index 0000000000000..753e6a95e3f9c
--- /dev/null
+++ b/test/IRGen/borrow_accessor_large.swift
@@ -0,0 +1,256 @@
+// RUN: %target-swift-frontend -c %s -Xllvm -sil-print-after=loadable-address  -enable-experimental-feature BorrowAndMutateAccessors  2>&1 | %FileCheck %s
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+// REQUIRES: OS=macosx
+
+public class Klass {
+  var id: Int = 0
+}
+
+@inline(never)
+func use(_ k: Klass) {
+  print(k.id)
+}
+
+@inline(never)
+func use(_ s: SmallStruct) {
+  print(s.id)
+}
+
+@inline(never)
+func use(_ tuple: (Klass, Klass, Klass, Klass, Klass, Klass, Klass, Klass)) {
+  print(tuple.4.id)
+}
+
+@inline(never)
+func use(_ ls: LargeProp) { 
+  use(ls._largeTuple)
+}
+
+@inline(never)
+func use(_ k: borrowing  NC) {
+  print(k.id)
+}
+
+@inline(never)
+func use(_ ls: borrowing LargeNCProp) { 
+  use(ls.nc1)
+  use(ls.nc2)
+  use(ls.nc3)
+  use(ls.nc4)
+  use(ls.nc5)
+  use(ls.nc6)
+  use(ls.nc7)
+  use(ls.nc8)
+}
+
+public struct LargeProp {
+  var _largeTuple = (Klass(), Klass(), Klass(), Klass(), Klass(), Klass(), Klass(), Klass())
+}
+
+public struct LargeNCProp : ~Copyable {
+  var nc1 = NC()
+  var nc2 = NC()
+  var nc3 = NC()
+  var nc4 = NC()
+  var nc5 = NC()
+  var nc6 = NC()
+  var nc7 = NC()
+  var nc8 = NC()
+}
+
+public struct SmallStruct {
+  var id = 0
+}
+
+public struct LargeStruct {
+  var _k = Klass()
+  var _t = (1, 2, 3, 4, 5, 6, 7, 8)
+  var _largeTuple = (Klass(), Klass(), Klass(), Klass(), Klass(), Klass(), Klass(), Klass())
+  var _largeProp = LargeProp()
+  var _smallStruct = SmallStruct()
+
+  var borrowKlass: Klass {
+    borrow {
+      return _k
+    }
+  }
+  var borrowSmallStruct: SmallStruct {
+    borrow {
+      return _smallStruct
+    }
+  }
+  var largePropBorrow: LargeProp {
+    borrow {
+      return _largeProp
+    }
+  }
+  var largeTupleBorrow: (Klass, Klass, Klass, Klass, Klass, Klass, Klass, Klass) {
+    borrow {
+      return _largeTuple
+    }
+  }
+}
+
+func test() {
+  let l = LargeStruct()
+  use(l.borrowKlass)
+  use(l.borrowSmallStruct)
+  let k = l.borrowKlass
+  use(k)
+  use(l.largeTupleBorrow)
+  use(l.largePropBorrow)
+  use(k)
+}
+
+public struct NC : ~Copyable {
+  var id: Int = 0
+}
+
+public struct NCLargeStruct : ~Copyable {
+  var _k = NC()
+  var _largeProp = LargeNCProp()
+
+  var borrowNC: NC {
+    borrow {
+      return _k
+    }
+  }
+  var largePropBorrow: LargeNCProp {
+    borrow {
+      return _largeProp
+    }
+  }
+}
+
+func nctest() {
+  let l = NCLargeStruct()
+  use(l.borrowNC)
+  use(l.largePropBorrow)
+}
+
+// CHECK: sil hidden @$s21borrow_accessor_large11LargeStructV0A5KlassAA0F0Cvb : $@convention(method) (@in_guaranteed LargeStruct) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $*LargeStruct):
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #LargeStruct._k
+// CHECK:   [[REG3:%.*]] = load [[REG2]]
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// IRGen result type is PtrTy because we are returning a class reference 
+// CHECK-IRGEN: define hidden swiftcc ptr @"$s21borrow_accessor_large11LargeStructV0A5KlassAA0F0Cvb"(ptr noalias nocapture swiftself dereferenceable(208) [[REG0]]) {{.*}} {
+// CHECK-IRGEN: entry:
+// CHECK-IRGEN:   %._k = getelementptr inbounds %T21borrow_accessor_large11LargeStructV, ptr [[REG0]], i32 0, i32 0
+// CHECK-IRGEN:   [[REG1:%.*]] = load ptr, ptr %._k, align 8
+// CHECK-IRGEN:   ret ptr [[REG1]]
+// CHECK-IRGEN: }
+
+// CHECK: sil hidden @$s21borrow_accessor_large11LargeStructV0a5SmallE0AA0fE0Vvb : $@convention(method) (@in_guaranteed LargeStruct) -> SmallStruct {
+// CHECK: bb0([[REG0:%.*]] : $*LargeStruct):
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #LargeStruct._smallStruct
+// CHECK:   [[REG3:%.*]] = load [[REG2]]
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// CHECK-IRGEN: define hidden swiftcc i64 @"$s21borrow_accessor_large11LargeStructV0a5SmallE0AA0fE0Vvb"(ptr noalias nocapture swiftself dereferenceable(208) [[REG0]]) {{.*}} {
+// CHECK-IRGEN: entry:
+// CHECK-IRGEN:   %._smallStruct = getelementptr inbounds %T21borrow_accessor_large11LargeStructV, ptr [[REG0]], i32 0, i32 4
+// CHECK-IRGEN:   %._smallStruct.id = getelementptr inbounds %T21borrow_accessor_large11SmallStructV, ptr %._smallStruct, i32 0, i32 0
+// CHECK-IRGEN:   %._smallStruct.id._value = getelementptr inbounds %TSi, ptr %._smallStruct.id, i32 0, i32 0
+// CHECK-IRGEN:   [[REG1:%.*]] = load i64, ptr %._smallStruct.id._value, align 8
+// CHECK-IRGEN:   ret i64 [[REG1]]
+// CHECK-IRGEN: }
+
+// LoadableByAddress transforms to an indirect result
+// CHECK: sil hidden @$s21borrow_accessor_large11LargeStructV0C10PropBorrowAA0dF0Vvb : $@convention(method) (@in_guaranteed LargeStruct) -> @out LargeProp {
+// CHECK: bb0([[REG0:%.*]] : $*LargeProp, [[REG1:%.*]] : $*LargeStruct):
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG1]], #LargeStruct._largeProp
+// CHECK:   copy_addr [take] [[REG3]] to [init] [[REG0]]
+// CHECK:   [[REG5:%.*]] = tuple ()
+// CHECK:   return [[REG5]]
+// CHECK: }
+
+// CHECK-IRGEN: define hidden swiftcc void @"$s21borrow_accessor_large11LargeStructV0C10PropBorrowAA0dF0Vvb"(ptr noalias nocapture sret(%T21borrow_accessor_large9LargePropV) [[REG0]], ptr noalias nocapture swiftself dereferenceable(208) [[REG1]]) {{.*}} {
+// CHECK-IRGEN: entry:
+// CHECK-IRGEN:   %._largeProp = getelementptr inbounds %T21borrow_accessor_large11LargeStructV, ptr [[REG1]], i32 0, i32 3
+// CHECK-IRGEN:   call void @llvm.memcpy.p0.p0.i64(ptr align 8 [[REG0]], ptr align 8 %._largeProp, i64 64, i1 false)
+// CHECK-IRGEN:   ret void
+// CHECK-IRGEN: }
+
+// LoadableByAddress does not transform large tuples
+// CHECK: sil hidden @$s21borrow_accessor_large11LargeStructV0C11TupleBorrowAA5KlassC_A7Ftvb : $@convention(method) (@in_guaranteed LargeStruct) -> @guaranteed (Klass, Klass, Klass, Klass, Klass, Klass, Klass, Klass) {
+// CHECK: bb0([[REG0:%.*]] : $*LargeStruct):
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #LargeStruct._largeTuple
+// CHECK:   [[REG3:%.*]] = load [[REG2]]
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// CHECK-IRGEN: define hidden swiftcc void @"$s21borrow_accessor_large11LargeStructV0C11TupleBorrowAA5KlassC_A7Ftvb"(ptr noalias nocapture sret(<{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>) [[REG0]], ptr noalias nocapture swiftself dereferenceable(208) [[REG1]]) {{.*}} {
+// CHECK-IRGEN: entry:
+// CHECK-IRGEN:   %._largeTuple = getelementptr inbounds %T21borrow_accessor_large11LargeStructV, ptr [[REG1]], i32 0, i32 2
+// CHECK-IRGEN:   %._largeTuple.elt = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr %._largeTuple, i32 0, i32 0
+// CHECK-IRGEN:   [[REG2:%.*]] = load ptr, ptr %._largeTuple.elt, align 8
+// CHECK-IRGEN:   %._largeTuple.elt1 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr %._largeTuple, i32 0, i32 1
+// CHECK-IRGEN:   [[REG3:%.*]] = load ptr, ptr %._largeTuple.elt1, align 8
+// CHECK-IRGEN:   %._largeTuple.elt2 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr %._largeTuple, i32 0, i32 2
+// CHECK-IRGEN:   [[REG4:%.*]] = load ptr, ptr %._largeTuple.elt2, align 8
+// CHECK-IRGEN:   %._largeTuple.elt3 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr %._largeTuple, i32 0, i32 3
+// CHECK-IRGEN:   [[REG5:%.*]] = load ptr, ptr %._largeTuple.elt3, align 8
+// CHECK-IRGEN:   %._largeTuple.elt4 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr %._largeTuple, i32 0, i32 4
+// CHECK-IRGEN:   [[REG6:%.*]] = load ptr, ptr %._largeTuple.elt4, align 8
+// CHECK-IRGEN:   %._largeTuple.elt5 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr %._largeTuple, i32 0, i32 5
+// CHECK-IRGEN:   [[REG7:%.*]] = load ptr, ptr %._largeTuple.elt5, align 8
+// CHECK-IRGEN:   %._largeTuple.elt6 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr %._largeTuple, i32 0, i32 6
+// CHECK-IRGEN:   [[REG8:%.*]] = load ptr, ptr %._largeTuple.elt6, align 8
+// CHECK-IRGEN:   %._largeTuple.elt7 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr %._largeTuple, i32 0, i32 7
+// CHECK-IRGEN:   [[REG9:%.*]] = load ptr, ptr %._largeTuple.elt7, align 8
+// CHECK-IRGEN:   %.elt = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr [[REG0]], i32 0, i32 0
+// CHECK-IRGEN:   store ptr [[REG2]], ptr %.elt, align 8
+// CHECK-IRGEN:   %.elt8 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr [[REG0]], i32 0, i32 1
+// CHECK-IRGEN:   store ptr [[REG3]], ptr %.elt8, align 8
+// CHECK-IRGEN:   %.elt9 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr [[REG0]], i32 0, i32 2
+// CHECK-IRGEN:   store ptr [[REG4]], ptr %.elt9, align 8
+// CHECK-IRGEN:   %.elt10 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr [[REG0]], i32 0, i32 3
+// CHECK-IRGEN:   store ptr [[REG5]], ptr %.elt10, align 8
+// CHECK-IRGEN:   %.elt11 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr [[REG0]], i32 0, i32 4
+// CHECK-IRGEN:   store ptr [[REG6]], ptr %.elt11, align 8
+// CHECK-IRGEN:   %.elt12 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr [[REG0]], i32 0, i32 5
+// CHECK-IRGEN:   store ptr [[REG7]], ptr %.elt12, align 8
+// CHECK-IRGEN:   %.elt13 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr [[REG0]], i32 0, i32 6
+// CHECK-IRGEN:   store ptr [[REG8]], ptr %.elt13, align 8
+// CHECK-IRGEN:   %.elt14 = getelementptr inbounds <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }>, ptr [[REG0]], i32 0, i32 7
+// CHECK-IRGEN:   store ptr [[REG9]], ptr %.elt14, align 8
+// CHECK-IRGEN:   ret void
+// CHECK-IRGEN: }
+
+// CHECK: sil hidden @$s21borrow_accessor_large13NCLargeStructV0A2NCAA0F0Vvb : $@convention(method) (@in_guaranteed NCLargeStruct) -> @guaranteed NC {
+// CHECK: bb0([[REG0:%.*]] : $*NCLargeStruct):
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #NCLargeStruct._k
+// CHECK:   [[REG3:%.*]] = load [[REG2]]
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// CHECK-IRGEN: define hidden swiftcc i64 @"$s21borrow_accessor_large13NCLargeStructV0A2NCAA0F0Vvb"(ptr noalias nocapture swiftself dereferenceable(72) [[REG0]]) {{.*}} {
+// CHECK-IRGEN: entry:
+// CHECK-IRGEN:   %._k = getelementptr inbounds %T21borrow_accessor_large13NCLargeStructV, ptr [[REG0]], i32 0, i32 0
+// CHECK-IRGEN:   %._k.id = getelementptr inbounds %T21borrow_accessor_large2NCV, ptr %._k, i32 0, i32 0
+// CHECK-IRGEN:   %._k.id._value = getelementptr inbounds %TSi, ptr %._k.id, i32 0, i32 0
+// CHECK-IRGEN:   [[REG1:%.*]] = load i64, ptr %._k.id._value, align 8
+// CHECK-IRGEN:   ret i64 [[REG1]]
+// CHECK-IRGEN: }
+
+// Note: ~Copyable types are returned indirectly via copy_addy which in turn generates a memcopy
+// CHECK: sil hidden @$s21borrow_accessor_large13NCLargeStructV0C10PropBorrowAA11LargeNCPropVvb : $@convention(method) (@in_guaranteed NCLargeStruct) -> @out LargeNCProp {
+// CHECK: bb0([[REG0:%.*]] : $*LargeNCProp, [[REG1:%.*]] : $*NCLargeStruct):
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG1]], #NCLargeStruct._largeProp
+// CHECK:   copy_addr [take] [[REG3]] to [init] [[REG0]]
+// CHECK:   [[REG5:%.*]] = tuple ()
+// CHECK:   return [[REG5]]
+// CHECK: }
+
+// CHECK-IRGEN: define hidden swiftcc void @"$s21borrow_accessor_large13NCLargeStructV0C10PropBorrowAA11LargeNCPropVvb"(ptr noalias nocapture sret(%T21borrow_accessor_large11LargeNCPropV) [[REG0]], ptr noalias nocapture swiftself dereferenceable(72) [[REG1]]) {{.*}} {
+// CHECK-IRGEN: entry:
+// CHECK-IRGEN:   %._largeProp = getelementptr inbounds %T21borrow_accessor_large13NCLargeStructV, ptr [[REG1]], i32 0, i32 1
+// CHECK-IRGEN:   call void @llvm.memcpy.p0.p0.i64(ptr align 8 [[REG0]], ptr align 8 %._largeProp, i64 64, i1 false)
+// CHECK-IRGEN:   ret void
+// CHECK-IRGEN: }
+
diff --git a/test/IRGen/boxed_existential.sil b/test/IRGen/boxed_existential.sil
index 16870af6b1632..3c061cf6f27ee 100644
--- a/test/IRGen/boxed_existential.sil
+++ b/test/IRGen/boxed_existential.sil
@@ -81,7 +81,7 @@ entry(%b : $Error):
   // CHECK: [[ADDR:%.*]] = load {{.*}} [[OUT_ADDR]]
   %a = project_existential_box $SomeError in %b : $Error
 
-  // CHECK: [[GEP1:%.*]] = getelementptr inbounds %T17boxed_existential9SomeErrorV, ptr %2, i32 0, i32 1
+  // CHECK: [[GEP1:%.*]] = getelementptr inbounds{{.*}} %T17boxed_existential9SomeErrorV, ptr %2, i32 0, i32 1
   // CHECK: [[GEP2:%.*]] = getelementptr inbounds {{.*}} [[GEP1]], i32 0, i32 0
   %c = struct_element_addr %a : $*SomeError, #SomeError._code
 
diff --git a/test/IRGen/builtin_pack_length.swift b/test/IRGen/builtin_pack_length.swift
index e543df1d4e020..1a9af22f81fdc 100644
--- a/test/IRGen/builtin_pack_length.swift
+++ b/test/IRGen/builtin_pack_length.swift
@@ -31,7 +31,7 @@ func weirdPackCountUse1<each T>(_ x: repeat each T) -> Builtin.Word {
 }
 
 struct Pack<each T> {
-// CHECK: define {{.*}} @"$s8builtins4PackV5countBwvgZ"(i64 returned [[PACK_COUNT:%.*]], ptr nocapture readnone %"each T")
+// CHECK: define {{.*}} @"$s8builtins4PackV5countBwvgZ"(i64 returned [[PACK_COUNT:%.*]], ptr{{( nocapture)?}} readnone{{( captures\(none\))?}} %"each T")
 // CHECK-NEXT: entry:
 // CHECK-NEXT: ret i64 [[PACK_COUNT]]
   static var count: Builtin.Word {
diff --git a/test/IRGen/builtins.swift b/test/IRGen/builtins.swift
index 6cd0d59b5d317..c59e327a246fb 100644
--- a/test/IRGen/builtins.swift
+++ b/test/IRGen/builtins.swift
@@ -173,6 +173,57 @@ func shufflevector_test(_ src: Builtin.FPIEEE32) -> Builtin.Vec4xFPIEEE32 {
   )
 }
 
+func scalar_select_test(
+  _ predicate: Builtin.Int1,
+  _ trueValue: Builtin.Int32,
+  _ falseValue: Builtin.Int32
+) -> Builtin.Int32 {
+  // CHECK: scalar_select_test
+  // CHECK: select i1 %{{[0-9]+}}, i32 %{{[0-9]+}}, i32 %{{[0-9]+}}
+  Builtin.select_Int1_Int32(predicate, trueValue, falseValue)
+}
+
+func scalar_select_test_ii(
+  _ predicate: Builtin.Int1,
+  _ trueValue: Builtin.Vec4xInt32,
+  _ falseValue: Builtin.Vec4xInt32
+) -> Builtin.Vec4xInt32 {
+  // CHECK: scalar_select_test_ii
+  // CHECK: select i1 %{{[0-9]+}}, <4 x i32> %{{[0-9]+}}, <4 x i32> %{{[0-9]+}}
+  Builtin.select_Int1_Vec4xInt32(predicate, trueValue, falseValue)
+}
+
+func vector_select_test(
+  _ predicate: Builtin.Vec8xInt32,
+  _ trueValue: Builtin.Vec8xInt32,
+  _ falseValue: Builtin.Vec8xInt32
+) -> Builtin.Vec8xInt32 {
+  // CHECK: vector_select_test
+  // CHECK: select <8 x i1> %{{[0-9]+}}, <8 x i32> %{{[0-9]+}}, <8 x i32> %{{[0-9]+}}
+  let p = Builtin.trunc_Vec8xInt32_Vec8xInt1(predicate)
+  return Builtin.select_Vec8xInt1_Vec8xInt32(p, trueValue, falseValue)
+}
+
+func interleave_test(
+  _ evens: Builtin.Vec8xInt16,
+  _ odds: Builtin.Vec8xInt16
+) -> (Builtin.Vec8xInt16, Builtin.Vec8xInt16) {
+  // CHECK: interleave_test
+  // CHECK: shufflevector <8 x i16> %{{[0-9]+}}, <8 x i16> %{{[0-9]+}}, <8 x i32> <i32 0, i32 8, i32 1, i32 9, i32 2, i32 10, i32 3, i32 11>
+  // CHECK: shufflevector <8 x i16> %{{[0-9]+}}, <8 x i16> %{{[0-9]+}}, <8 x i32> <i32 4, i32 12, i32 5, i32 13, i32 6, i32 14, i32 7, i32 15>
+  return Builtin.interleave_Vec8xInt16(evens, odds)
+}
+
+func deinterleave_test(
+  _ low: Builtin.Vec8xInt16,
+  _ high: Builtin.Vec8xInt16
+) -> (Builtin.Vec8xInt16, Builtin.Vec8xInt16) {
+  // CHECK: deinterleave_test
+  // CHECK: shufflevector <8 x i16> %{{[0-9]+}}, <8 x i16> %{{[0-9]+}}, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
+  // CHECK: shufflevector <8 x i16> %{{[0-9]+}}, <8 x i16> %{{[0-9]+}}, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
+  return Builtin.deinterleave_Vec8xInt16(low, high)
+}
+
 func intrinsic_test(_ i32: inout Builtin.Int32, i16: inout Builtin.Int16,
                     _ v8i16: Builtin.Vec8xInt16) {
   // CHECK: intrinsic_test
@@ -212,11 +263,11 @@ func sizeof_alignof_metatype_test() {
 
 // CHECK: define hidden {{.*}}void @"$s8builtins27generic_sizeof_alignof_testyyxlF"
 func generic_sizeof_alignof_test<T>(_: T) {
-  // CHECK:      [[T0:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[T:%.*]], i32 0, i32 8
+  // CHECK:      [[T0:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[T:%.*]], i32 0, i32 8
   // CHECK-NEXT: [[SIZE:%.*]] = load i64, ptr [[T0]]
   // CHECK-NEXT: store i64 [[SIZE]], ptr [[S:%.*]]
   var s = Builtin.sizeof(T.self)
-  // CHECK:      [[T0:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[T:%.*]], i32 0, i32 10
+  // CHECK:      [[T0:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[T:%.*]], i32 0, i32 10
   // CHECK-NEXT: [[FLAGS:%.*]] = load i32, ptr [[T0]]
   // CHECK-NEXT: [[T2:%.*]] = zext i32 [[FLAGS]] to i64
   // CHECK-NEXT: [[T3:%.*]] = and i64 [[T2]], 255
@@ -227,7 +278,7 @@ func generic_sizeof_alignof_test<T>(_: T) {
 
 // CHECK: define hidden {{.*}}void @"$s8builtins21generic_strideof_testyyxlF"
 func generic_strideof_test<T>(_: T) {
-  // CHECK:      [[T0:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[T:%.*]], i32 9
+  // CHECK:      [[T0:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[T:%.*]], i32 9
   // CHECK-NEXT: [[STRIDE:%.*]] = load i64, ptr [[T0]]
   // CHECK-NEXT: store i64 [[STRIDE]], ptr [[S:%.*]]
   var s = Builtin.strideof(T.self)
@@ -329,9 +380,9 @@ func fneg_test(_ half: Builtin.FPIEEE16,
                double: Builtin.FPIEEE64)
   -> (Builtin.FPIEEE16, Builtin.FPIEEE32, Builtin.FPIEEE64)
 {
-  // CHECK: fsub half 0xH8000, {{%.*}}
-  // CHECK: fsub float -0.000000e+00, {{%.*}}
-  // CHECK: fsub double -0.000000e+00, {{%.*}}
+  // CHECK: fneg half
+  // CHECK: fneg float
+  // CHECK: fneg double
   return (Builtin.fneg_FPIEEE16(half),
           Builtin.fneg_FPIEEE32(single),
           Builtin.fneg_FPIEEE64(double))
@@ -595,6 +646,13 @@ func assumeNonNegative_test2(_ x: Builtin.Word) -> Builtin.Word {
   return Builtin.assumeNonNegative_Word(return_word(x))
 }
 
+// CHECK-LABEL: define hidden {{.*}}@"$s8builtins23assumeNonNegative_test3yBwBwF"
+func assumeNonNegative_test3(_ x: Builtin.Word) -> Builtin.Word {
+  // CHECK: [[C:%.*]] = icmp sge i{{[0-9]+}} %0, 0
+  // CHECK: call void @llvm.assume(i1 [[C]])
+  return Builtin.assumeNonNegative_Word(x)
+}
+
 struct Empty {}
 struct Pair { var i: Int, b: Bool }
 
@@ -638,11 +696,11 @@ func zeroInitializerEmpty() {
 // isUnique variants
 // ----------------------------------------------------------------------------
 
-// CHECK: define hidden {{.*}}void @"$s8builtins26acceptsBuiltinNativeObjectyyBoSgzF"(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define hidden {{.*}}void @"$s8builtins26acceptsBuiltinNativeObjectyyBoSgzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 func acceptsBuiltinNativeObject(_ ref: inout Builtin.NativeObject?) {}
 
 // native
-// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins8isUniqueyBi1_BoSgzF"(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins8isUniqueyBi1_BoSgzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-NEXT: entry:
 // CHECK:      %[[LD_RC:.+]] = load ptr, ptr %0
 // CHECK-NEXT: %[[RET:.+]] = call zeroext i1 @swift_isUniquelyReferenced_native(ptr %[[LD_RC]])
@@ -652,7 +710,7 @@ func isUnique(_ ref: inout Builtin.NativeObject?) -> Bool {
 }
 
 // native nonNull
-// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins8isUniqueyBi1_BozF"(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins8isUniqueyBi1_BozF"(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-NEXT: entry:
 // CHECK:      %[[LD_RC:.+]] = load ptr, ptr %0
 // CHECK:      %[[RET:.+]] = call zeroext i1 @swift_isUniquelyReferenced_nonNull_native(ptr %[[LD_RC]])
@@ -661,13 +719,13 @@ func isUnique(_ ref: inout Builtin.NativeObject) -> Bool {
   return Builtin.isUnique(&ref)
 }
 
-// CHECK: define hidden {{.*}}void @"$s8builtins16acceptsAnyObjectyyyXlSgzF"(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define hidden {{.*}}void @"$s8builtins16acceptsAnyObjectyyyXlSgzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 func acceptsAnyObject(_ ref: inout Builtin.AnyObject?) {}
 
 // ObjC
-// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins8isUniqueyBi1_yXlSgzF"(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins8isUniqueyBi1_yXlSgzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-NEXT: entry:
-// CHECK:      [[ADDR:%.+]] = getelementptr inbounds [[OPTIONAL_ANYOBJECT_TY:%.*]], ptr %0, i32 0, i32 0
+// CHECK:      [[ADDR:%.+]] = getelementptr inbounds{{.*}} [[OPTIONAL_ANYOBJECT_TY:%.*]], ptr %0, i32 0, i32 0
 // CHECK-NEXT: [[REF:%.+]] = load ptr, ptr [[ADDR]]
 // CHECK-objc-NEXT: [[RESULT:%.+]] = call zeroext i1 @swift_isUniquelyReferenced{{(NonObjC)?}}(ptr [[REF]])
 // CHECK-native-NEXT: [[RESULT:%.+]] = call zeroext i1 @swift_isUniquelyReferenced_native(ptr [[REF]])
@@ -678,9 +736,9 @@ func isUnique(_ ref: inout Builtin.AnyObject?) -> Bool {
 
 // ObjC nonNull
 // CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins8isUniqueyBi1_yXlzF"
-// CHECK-SAME:    (ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-SAME:    (ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-NEXT: entry:
-// CHECK:      [[ADDR:%.+]] = getelementptr inbounds %AnyObject, ptr %0, i32 0, i32 0
+// CHECK:      [[ADDR:%.+]] = getelementptr inbounds{{.*}} %AnyObject, ptr %0, i32 0, i32 0
 // CHECK:      [[REF:%.+]] = load ptr, ptr [[ADDR]]
 // CHECK-objc-NEXT: [[RESULT:%.+]] = call zeroext i1 @swift_isUniquelyReferenced{{(NonObjC)?}}_nonNull(ptr [[REF]])
 // CHECK-native-NEXT: [[RESULT:%.+]] = call zeroext i1 @swift_isUniquelyReferenced_nonNull_native(ptr [[REF]])
@@ -690,7 +748,7 @@ func isUnique(_ ref: inout Builtin.AnyObject) -> Bool {
 }
 
 // BridgeObject nonNull
-// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins8isUniqueyBi1_BbzF"(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins8isUniqueyBi1_BbzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-NEXT: entry:
 // CHECK:      %[[LD:.+]] = load ptr, ptr %0
 // CHECK:      %[[RET:.+]] = call zeroext i1 @swift_isUniquelyReferenced{{(NonObjC)?}}_nonNull_bridgeObject(ptr %[[LD]])
@@ -706,7 +764,7 @@ func assumeTrue(_ x: Builtin.Int1) {
   Builtin.assume_Int1(x)
 }
 // BridgeObject nonNull
-// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins15isUnique_nativeyBi1_BbzF"(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins15isUnique_nativeyBi1_BbzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-NEXT: entry:
 // CHECK:      %[[LD:.+]] = load ptr, ptr %0
 // CHECK-NEXT: %[[RET:.+]] = call zeroext i1 @swift_isUniquelyReferenced_nonNull_native(ptr %[[LD]])
@@ -716,7 +774,7 @@ func isUnique_native(_ ref: inout Builtin.BridgeObject) -> Bool {
 }
 
 // ImplicitlyUnwrappedOptional argument to isUnique.
-// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins11isUniqueIUOyBi1_BoSgzF"(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define hidden {{.*}}i1 @"$s8builtins11isUniqueIUOyBi1_BoSgzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-NEXT: entry:
 // CHECK: call zeroext i1 @swift_isUniquelyReferenced_native(ptr
 // CHECK: ret i1
@@ -733,7 +791,7 @@ func COWBufferForReading(_ ref: __owned C) -> C {
 
 // CHECK-LABEL: define {{.*}} @{{.*}}generic_ispod_test
 func generic_ispod_test<T>(_: T) {
-  // CHECK:      [[T0:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[T:%.*]], i32 10
+  // CHECK:      [[T0:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[T:%.*]], i32 10
   // CHECK-NEXT: [[FLAGS:%.*]] = load i32, ptr [[T0]]
   // CHECK-NEXT: [[ISNOTPOD:%.*]] = and i32 [[FLAGS]], 65536
   // CHECK-NEXT: [[ISPOD:%.*]] = icmp eq i32 [[ISNOTPOD]], 0
@@ -752,7 +810,7 @@ func ispod_test() {
 
 // CHECK-LABEL: define {{.*}} @{{.*}}generic_isbitwisetakable_test
 func generic_isbitwisetakable_test<T>(_: T) {
-  // CHECK:      [[T0:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[T:%.*]], i32 10
+  // CHECK:      [[T0:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[T:%.*]], i32 10
   // CHECK-NEXT: [[FLAGS:%.*]] = load i32, ptr [[T0]]
   // CHECK-NEXT: [[ISNOTBITWISETAKABLE:%.*]] = and i32 [[FLAGS]], 1048576
   // CHECK-NEXT: [[ISBITWISETAKABLE:%.*]] = icmp eq i32 [[ISNOTBITWISETAKABLE]], 0
diff --git a/test/IRGen/c_layout.sil b/test/IRGen/c_layout.sil
index 6178b60f1d5d6..e26bfa01a10dd 100644
--- a/test/IRGen/c_layout.sil
+++ b/test/IRGen/c_layout.sil
@@ -32,55 +32,55 @@ bb0:
 // CHECK-x86_64:   [[RESULT:%.*]] = alloca %TSo11BitfieldOneV, align 8
 // CHECK-x86_64:   [[ARG:%.*]] = alloca %TSo11BitfieldOneV, align 8
 //   Make the first call and pull all the values out of the indirect result.
-// CHECK-x86_64:   call void @createBitfieldOne(ptr noalias nocapture sret({{.*}}) [[RESULT]])
-// CHECK-x86_64:   [[ADDR_A:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 0
-// CHECK-x86_64:   [[ADDR_A_V:%.*]] = getelementptr inbounds %Ts6UInt32V, ptr [[ADDR_A]], i32 0, i32 0
+// CHECK-x86_64:   call void @createBitfieldOne(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[RESULT]])
+// CHECK-x86_64:   [[ADDR_A:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_A_V:%.*]] = getelementptr inbounds{{.*}} %Ts6UInt32V, ptr [[ADDR_A]], i32 0, i32 0
 // CHECK-x86_64:   [[A:%.*]] = load i32, ptr [[ADDR_A_V]], align 8
-// CHECK-x86_64:   [[ADDR_B:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 1
-// CHECK-x86_64:   [[ADDR_B_X:%.*]] = getelementptr inbounds %TSo6NestedV, ptr [[ADDR_B]], i32 0, i32 0
-// CHECK-x86_64:   [[ADDR_B_X_V:%.*]] = getelementptr inbounds %TSf, ptr [[ADDR_B_X]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_B:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 1
+// CHECK-x86_64:   [[ADDR_B_X:%.*]] = getelementptr inbounds{{.*}} %TSo6NestedV, ptr [[ADDR_B]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_B_X_V:%.*]] = getelementptr inbounds{{.*}} %TSf, ptr [[ADDR_B_X]], i32 0, i32 0
 // CHECK-x86_64:   [[B_X:%.*]] = load float, ptr [[ADDR_B_X_V]], align 4
-// CHECK-x86_64:   [[ADDR_B_YZ:%.*]] = getelementptr inbounds %TSo6NestedV, ptr [[ADDR_B]], i32 0, i32 1
+// CHECK-x86_64:   [[ADDR_B_YZ:%.*]] = getelementptr inbounds{{.*}} %TSo6NestedV, ptr [[ADDR_B]], i32 0, i32 1
 // CHECK-x86_64:   [[B_YZ:%.*]] = load i24, ptr [[ADDR_B_YZ]], align 4
-// CHECK-x86_64:   [[ADDR_CDE:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 2
+// CHECK-x86_64:   [[ADDR_CDE:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 2
 // CHECK-x86_64:   [[CDE:%.*]] = load i32, ptr [[ADDR_CDE]], align 4
-// CHECK-x86_64:   [[ADDR_FGH:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 3
+// CHECK-x86_64:   [[ADDR_FGH:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 3
 // CHECK-x86_64:   [[FGH:%.*]] = load i32, ptr [[ADDR_FGH]], align 8
-// CHECK-x86_64:   [[ADDR_I:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 4
-// CHECK-x86_64:   [[ADDR_I_V:%.*]] = getelementptr inbounds %TSf, ptr [[ADDR_I]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_I:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 4
+// CHECK-x86_64:   [[ADDR_I_V:%.*]] = getelementptr inbounds{{.*}} %TSf, ptr [[ADDR_I]], i32 0, i32 0
 // CHECK-x86_64:   [[I:%.*]] = load float, ptr [[ADDR_I_V]], align 4
-// CHECK-x86_64:   [[ADDR_JK:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 5
+// CHECK-x86_64:   [[ADDR_JK:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 5
 // CHECK-x86_64:   [[JK:%.*]] = load i8, ptr [[ADDR_JK]], align 8
-// CHECK-x86_64:   [[ADDR_L:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 7
-// CHECK-x86_64:   [[ADDR_L_V:%.*]] = getelementptr inbounds %Ts6UInt64V, ptr [[ADDR_L]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_L:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 7
+// CHECK-x86_64:   [[ADDR_L_V:%.*]] = getelementptr inbounds{{.*}} %Ts6UInt64V, ptr [[ADDR_L]], i32 0, i32 0
 // CHECK-x86_64:   [[L:%.*]] = load i64, ptr [[ADDR_L_V]], align 8
-// CHECK-x86_64:   [[ADDR_M:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 8
-// CHECK-x86_64:   [[ADDR_M_V:%.*]] = getelementptr inbounds %Ts6UInt32V, ptr [[ADDR_M]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_M:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[RESULT]], i32 0, i32 8
+// CHECK-x86_64:   [[ADDR_M_V:%.*]] = getelementptr inbounds{{.*}} %Ts6UInt32V, ptr [[ADDR_M]], i32 0, i32 0
 // CHECK-x86_64:   [[M:%.*]] = load i32, ptr [[ADDR_M_V]], align 8
 //   Put all of the values into the indirect argument and make the second call.
-// CHECK-x86_64:   [[ADDR_A:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 0
-// CHECK-x86_64:   [[ADDR_A_V:%.*]] = getelementptr inbounds %Ts6UInt32V, ptr [[ADDR_A]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_A:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_A_V:%.*]] = getelementptr inbounds{{.*}} %Ts6UInt32V, ptr [[ADDR_A]], i32 0, i32 0
 // CHECK-x86_64:   store i32 [[A]], ptr [[ADDR_A_V]], align 8
-// CHECK-x86_64:   [[ADDR_B:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 1
-// CHECK-x86_64:   [[ADDR_B_X:%.*]] = getelementptr inbounds %TSo6NestedV, ptr [[ADDR_B]], i32 0, i32 0
-// CHECK-x86_64:   [[ADDR_B_X_V:%.*]] = getelementptr inbounds %TSf, ptr [[ADDR_B_X]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_B:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 1
+// CHECK-x86_64:   [[ADDR_B_X:%.*]] = getelementptr inbounds{{.*}} %TSo6NestedV, ptr [[ADDR_B]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_B_X_V:%.*]] = getelementptr inbounds{{.*}} %TSf, ptr [[ADDR_B_X]], i32 0, i32 0
 // CHECK-x86_64:   store float [[B_X]], ptr [[ADDR_B_X_V]], align 4
-// CHECK-x86_64:   [[ADDR_B_YZ:%.*]] = getelementptr inbounds %TSo6NestedV, ptr [[ADDR_B]], i32 0, i32 1
+// CHECK-x86_64:   [[ADDR_B_YZ:%.*]] = getelementptr inbounds{{.*}} %TSo6NestedV, ptr [[ADDR_B]], i32 0, i32 1
 // CHECK-x86_64:   store i24 [[B_YZ]], ptr [[ADDR_B_YZ]], align 4
-// CHECK-x86_64:   [[ADDR_CDE:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 2
+// CHECK-x86_64:   [[ADDR_CDE:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 2
 // CHECK-x86_64:   store i32 [[CDE]], ptr [[ADDR_CDE]], align 4
-// CHECK-x86_64:   [[ADDR_FGH:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 3
+// CHECK-x86_64:   [[ADDR_FGH:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 3
 // CHECK-x86_64:   store i32 [[FGH]], ptr [[ADDR_FGH]], align 8
-// CHECK-x86_64:   [[ADDR_I:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 4
-// CHECK-x86_64:   [[ADDR_I_V:%.*]] = getelementptr inbounds %TSf, ptr [[ADDR_I]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_I:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 4
+// CHECK-x86_64:   [[ADDR_I_V:%.*]] = getelementptr inbounds{{.*}} %TSf, ptr [[ADDR_I]], i32 0, i32 0
 // CHECK-x86_64:   store float [[I]], ptr [[ADDR_I_V]], align 4
-// CHECK-x86_64:   [[ADDR_JK:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 5
+// CHECK-x86_64:   [[ADDR_JK:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 5
 // CHECK-x86_64:   store i8 [[JK]], ptr [[ADDR_JK]], align 8
-// CHECK-x86_64:   [[ADDR_L:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 7
-// CHECK-x86_64:   [[ADDR_L_V:%.*]] = getelementptr inbounds %Ts6UInt64V, ptr [[ADDR_L]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_L:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 7
+// CHECK-x86_64:   [[ADDR_L_V:%.*]] = getelementptr inbounds{{.*}} %Ts6UInt64V, ptr [[ADDR_L]], i32 0, i32 0
 // CHECK-x86_64:   store i64 [[L]], ptr [[ADDR_L_V]], align 8
-// CHECK-x86_64:   [[ADDR_M:%.*]] = getelementptr inbounds %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 8
-// CHECK-x86_64:   [[ADDR_M_V:%.*]] = getelementptr inbounds %Ts6UInt32V, ptr [[ADDR_M]], i32 0, i32 0
+// CHECK-x86_64:   [[ADDR_M:%.*]] = getelementptr inbounds{{.*}} %TSo11BitfieldOneV, ptr [[ARG]], i32 0, i32 8
+// CHECK-x86_64:   [[ADDR_M_V:%.*]] = getelementptr inbounds{{.*}} %Ts6UInt32V, ptr [[ADDR_M]], i32 0, i32 0
 // CHECK-x86_64:   store i32 [[M]], ptr [[ADDR_M_V]], align 8
 // CHECK-SYSV-x86_64:  call void @consumeBitfieldOne(ptr byval({{.*}}) align 8 [[ARG]])
 // CHECK-WIN-x86_64:   call void @consumeBitfieldOne(ptr [[ARG]])
@@ -102,7 +102,7 @@ sil public_external @consumeSIMDStruct : $@convention(c) (SIMDStruct) -> ()
 
 // CHECK-x86_64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testSIMDStruct()
 // CHECK-SYSV-x86_64:        call <3 x float> @createSIMDStruct
-// CHECK-WIN-x86_64:         call void @createSIMDStruct(ptr noalias nocapture sret({{.*}}) %
+// CHECK-WIN-x86_64:         call void @createSIMDStruct(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %
 // CHECK-SYSV-x86_64:        call void @consumeSIMDStruct(<3 x float>
 // CHECK-WIN-x86_64:         call void @consumeSIMDStruct(ptr %
 sil @testSIMDStruct : $() -> () {
@@ -389,8 +389,8 @@ entry(%b : $@convention(block) (CChar) -> CChar, %c : $CChar):
 }
 
 // CHECK-x86_64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testBitfieldInBlock
-// CHECK-SYSV-x86_64:        call void {{%.*}}(ptr noalias nocapture sret({{.*}}) {{%.*}}, ptr {{%.*}}, ptr byval({{.*}}) align 8 {{%.*}})
-// CHECK-WIN-x86_64:         call void {{%.*}}(ptr noalias nocapture sret({{.*}}) {{%.*}}, ptr {{%.*}}, ptr {{%.*}})
+// CHECK-SYSV-x86_64:        call void {{%.*}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{%.*}}, ptr {{%.*}}, ptr byval({{.*}}) align 8 {{%.*}})
+// CHECK-WIN-x86_64:         call void {{%.*}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{%.*}}, ptr {{%.*}}, ptr {{%.*}})
 sil @testBitfieldInBlock : $@convention(thin) (@owned @convention(block) (BitfieldOne) -> BitfieldOne, BitfieldOne) -> BitfieldOne  {
 entry(%b : $@convention(block) (BitfieldOne) -> BitfieldOne, %x : $BitfieldOne):
   %r = apply %b(%x) : $@convention(block) (BitfieldOne) -> BitfieldOne
diff --git a/test/IRGen/casts.sil b/test/IRGen/casts.sil
index 13f0967353f4f..494f6384ba23e 100644
--- a/test/IRGen/casts.sil
+++ b/test/IRGen/casts.sil
@@ -1,6 +1,6 @@
 // RUN: %target-swift-frontend %s -emit-ir -enable-objc-interop -disable-objc-attr-requires-foundation-module | %FileCheck %s -DINT=i%target-ptrsize
 
-// REQUIRES: CPU=i386 || CPU=x86_64
+// REQUIRES: CPU=i386 || CPU=x86_64 || CPU=arm64
 
 sil_stage canonical
 
@@ -11,11 +11,14 @@ struct NotClass {}
 
 class A {}
 class B: A {}
+final class F: A {}
+protocol Q {}
 
 sil_vtable A {}
 sil_vtable B {}
+sil_vtable F {}
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @unchecked_addr_cast(ptr noalias nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @unchecked_addr_cast(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 sil @unchecked_addr_cast : $(@in A) -> B {
 entry(%a : $*A):
   %b = unchecked_addr_cast %a : $*A to $*B
@@ -115,6 +118,42 @@ entry(%a : $@thick Any.Type):
   return %p : $@thick (CP & OP & CP2).Type
 }
 
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @unconditional_fast_class_cast(ptr %0)
+// CHECK:         [[ISA:%.*]] = load ptr, ptr %0
+// CHECK:         [[NE:%.*]] = icmp ne {{.*}}, [[ISA]]
+// CHECK:         [[E:%.*]] = call i1 @llvm.expect.i1(i1 [[NE]], i1 false) 
+// CHECK:         br i1 [[E]], label %[[TRAPBB:[0-9]*]], label %[[RETBB:[0-9]*]]
+// CHECK:       [[RETBB]]:
+// CHECK-NEXT:    ret ptr %0
+// CHECK:       [[TRAPBB]]:
+// CHECK-NEXT:    call void @llvm.trap()
+sil @unconditional_fast_class_cast : $@convention(thin) (@owned A) -> @owned F {
+entry(%0 : $A):
+  %1 = unconditional_checked_cast %0 to F
+  return %1
+}
+
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @unconditional_optional_fast_class_cast(i64 %0)
+// CHECK:         [[PTR:%.*]] = inttoptr i64 %0 to ptr
+// CHECK:         [[ISNULL:%.*]] = icmp eq ptr [[PTR]], null
+// CHECK:         [[ENN:%.*]] = call i1 @llvm.expect.i1(i1 [[ISNULL]], i1 false) 
+// CHECK:         br i1 [[ENN]], label %[[NULLTRAPBB:[0-9]*]], label %[[CONTBB:[0-9]*]]
+// CHECK:       [[CONTBB]]:
+// CHECK:         [[ISA:%.*]] = load ptr, ptr [[PTR]]
+// CHECK:         [[NE:%.*]] = icmp ne {{.*}}, [[ISA]]
+// CHECK:         [[E:%.*]] = call i1 @llvm.expect.i1(i1 [[NE]], i1 false) 
+// CHECK:         br i1 [[E]], label %[[TRAPBB:[0-9]*]], label %[[RETBB:[0-9]*]]
+// CHECK:       [[RETBB]]:
+// CHECK-NEXT:    ret ptr [[PTR]]
+// CHECK:       [[NULLTRAPBB]]:
+// CHECK-NEXT:    call void @llvm.trap()
+// CHECK:       [[TRAPBB]]:
+// CHECK-NEXT:    call void @llvm.trap()
+sil @unconditional_optional_fast_class_cast : $@convention(thin) (@owned Optional<A>) -> @owned F {
+entry(%0 : $Optional<A>):
+  %1 = unconditional_checked_cast %0 to F
+  return %1
+}
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @c_cast_to_class_existential(ptr %0)
 // CHECK:         call { ptr, ptr } @dynamic_cast_existential_1_conditional(ptr {{.*}}, ptr %.Type, {{.*}} @"$s5casts2CPMp"
@@ -397,3 +436,24 @@ bb2:
 bb3(%11 : $Optional<C & PAnyObject>):
   return %11 : $Optional<C & PAnyObject>
 }
+
+// CHECK-LABEL: define{{.*}} @checked_cast_optional_metatype
+// CHECK: [[COND:%.*]] = icmp ne ptr {{%.*}}, null
+// CHECK-NEXT: br i1 [[COND]], label %is-non-nil, label %is-nil
+// CHECK: nil-checked-cont:
+// CHECK:   %4 = phi { ptr, ptr } [ {{%.*}}, %is-non-nil ], [ zeroinitializer, %is-nil ]
+sil @checked_cast_optional_metatype : $@convention(thin) (Optional<@thick any Any.Type>) -> Optional<@thick any Q.Type> {
+bb0(%0 : $Optional<@thick any Any.Type>):
+  checked_cast_br Optional<any Any.Type> in %0 to any Q.Type, bb1, bb2
+
+bb1(%3 : $@thick any Q.Type):
+  %4 = enum $Optional<@thick any Q.Type>, #Optional.some!enumelt, %3
+  br bb3(%4)
+
+bb2:
+  %6 = enum $Optional<@thick any Q.Type>, #Optional.none!enumelt
+  br bb3(%6)
+
+bb3(%8 : $Optional<@thick any Q.Type>):
+  return %8
+}
diff --git a/test/IRGen/cdecl_implementation.swift b/test/IRGen/cdecl_implementation.swift
new file mode 100644
index 0000000000000..58c553dfa885d
--- /dev/null
+++ b/test/IRGen/cdecl_implementation.swift
@@ -0,0 +1,47 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   -enable-experimental-feature CImplementation \
+// RUN:   -enable-experimental-feature CDecl \
+// RUN:   -disable-objc-interop \
+// RUN:   -F %clang-importer-sdk-path/frameworks %s \
+// RUN:   -import-objc-header %S/Inputs/objc_implementation.h -emit-ir \
+// RUN:   -target %target-future-triple > %t.ir
+// RUN: %FileCheck --input-file %t.ir %s
+
+// REQUIRES: swift_feature_CImplementation
+// REQUIRES: swift_feature_CDecl
+
+@implementation @c
+public func implFunc(_ param: Int32) {}
+
+@implementation @c
+public func implFuncCName(_ param: Int32) {}
+
+@implementation @c(implFuncRenamed_C)
+public func implFuncRenamed_Swift(param: Int32) {}
+
+public func fn() {
+  implFunc(2)
+  implFuncCName(3)
+  implFuncRenamed_Swift(param: 4)
+}
+
+/// implFunc(_:)
+// CHECK-LABEL: define{{.*}} void @implFunc
+
+// FIXME: We'd like this to be internal or hidden, not public.
+// CHECK: define{{.*}} swiftcc void @"$s20cdecl_implementation8implFuncyys5Int32VF"
+
+/// inplFuncCName(_:)
+// CHECK-LABEL: define{{.*}} void @"\01_implFuncAsmName"
+
+// FIXME: We'd like this to be internal or hidden, not public.
+// CHECK: define{{.*}} swiftcc void @"$s20cdecl_implementation13implFuncCNameyys5Int32VF"
+
+/// fn()
+// CHECK-LABEL: define{{.*}} swiftcc void @"$s20cdecl_implementation2fnyyF"
+// CHECK:   call void @implFunc
+// CHECK:   call void @"\01_implFuncAsmName"
+// CHECK:   call void @implFuncRenamed_C
+// CHECK:   ret void
+// CHECK: }
+
diff --git a/test/IRGen/class.sil b/test/IRGen/class.sil
index 1176280a2caaf..08b0d525d1714 100644
--- a/test/IRGen/class.sil
+++ b/test/IRGen/class.sil
@@ -154,6 +154,6 @@ entry(%x : $ClassConstrainedGenericField<ClassConstraintConformance>):
   return %b : $ClassConstraintConformance
 }
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @fixed_class_generic_field(ptr %0)
-// CHECK:         [[FIELD_ADDR_GENERIC:%.*]] = getelementptr inbounds %T5class28ClassConstrainedGenericFieldCyAA0B21ConstraintConformanceCG, ptr %0, i32 0, i32 1
+// CHECK:         [[FIELD_ADDR_GENERIC:%.*]] = getelementptr inbounds{{.*}} %T5class28ClassConstrainedGenericFieldCyAA0B21ConstraintConformanceCG, ptr %0, i32 0, i32 1
 // CHECK:         load ptr, ptr [[FIELD_ADDR_GENERIC]]
 
diff --git a/test/IRGen/class_bounded_generics.swift b/test/IRGen/class_bounded_generics.swift
index ecb5d56460187..5f796216be3e1 100644
--- a/test/IRGen/class_bounded_generics.swift
+++ b/test/IRGen/class_bounded_generics.swift
@@ -218,9 +218,9 @@ func class_protocol_field_struct_fields
 func class_generic_field_class_fields<T>
 (_ x:ClassGenericFieldClass<T>) -> (Int, T, Int) {
   return (x.x, x.y, x.z)
-  // CHECK: getelementptr inbounds %T22class_bounded_generics017ClassGenericFieldD0C, ptr %0, i32 0, i32 1
-  // CHECK: getelementptr inbounds %T22class_bounded_generics017ClassGenericFieldD0C, ptr %0, i32 0, i32 2
-  // CHECK: getelementptr inbounds %T22class_bounded_generics017ClassGenericFieldD0C, ptr %0, i32 0, i32 3
+  // CHECK: getelementptr inbounds{{.*}} %T22class_bounded_generics017ClassGenericFieldD0C, ptr %0, i32 0, i32 1
+  // CHECK: getelementptr inbounds{{.*}} %T22class_bounded_generics017ClassGenericFieldD0C, ptr %0, i32 0, i32 2
+  // CHECK: getelementptr inbounds{{.*}} %T22class_bounded_generics017ClassGenericFieldD0C, ptr %0, i32 0, i32 3
 }
 
 // CHECK-LABEL: define hidden swiftcc { i64, ptr, ptr, i64 } @"$s22class_bounded_generics0a16_protocol_field_A7_fields{{[_0-9a-zA-Z]*}}F"(ptr %0)
diff --git a/test/IRGen/class_field_other_module.swift b/test/IRGen/class_field_other_module.swift
index b74db17246396..5fd86082ef620 100644
--- a/test/IRGen/class_field_other_module.swift
+++ b/test/IRGen/class_field_other_module.swift
@@ -7,20 +7,20 @@
 
 import other_class
 
-// CHECK-LABEL: define {{(protected )?}}{{(dllexport )?}}swiftcc i32 @"$s24class_field_other_module12getSubclassXys5Int32V0c1_A00F0CF"(ptr nocapture readonly %0)
+// CHECK-LABEL: define {{(protected )?}}{{(dllexport )?}}swiftcc i32 @"$s24class_field_other_module12getSubclassXys5Int32V0c1_A00F0CF"(ptr{{( nocapture)?}} readonly{{( captures\(none\))?}} %0)
 // CHECK-NEXT: entry:
 // An Int32 after the heap object header
-// CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, ptr %0, i64 16
+// CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds{{.*}} i8, ptr %0, i64 16
 // CHECK-NEXT: [[RESULT:%.*]] = load i32, ptr [[GEP]]
 // CHECK-NEXT: ret i32 [[RESULT]]
 public func getSubclassX(_ o: Subclass) -> Int32 {
   return o.x
 }
 
-// CHECK-LABEL: define {{(protected )?}}{{(dllexport )?}}swiftcc i32 @"$s24class_field_other_module12getSubclassYys5Int32V0c1_A00F0CF"(ptr nocapture readonly %0)
+// CHECK-LABEL: define {{(protected )?}}{{(dllexport )?}}swiftcc i32 @"$s24class_field_other_module12getSubclassYys5Int32V0c1_A00F0CF"(ptr{{( nocapture)?}} readonly{{( captures\(none\))?}} %0)
 // CHECK-NEXT: entry:
 // An Int32 after an Int32 after the heap object header
-// CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, ptr %0, i64 20
+// CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds{{.*}} i8, ptr %0, i64 20
 // CHECK-NEXT: [[RESULT:%.*]] = load i32, ptr [[GEP]]
 // CHECK-NEXT: ret i32 [[RESULT]]
 public func getSubclassY(_ o: Subclass) -> Int32 {
diff --git a/test/IRGen/class_resilience.swift b/test/IRGen/class_resilience.swift
index 361cf1804e85b..508b90872dcc4 100644
--- a/test/IRGen/class_resilience.swift
+++ b/test/IRGen/class_resilience.swift
@@ -290,7 +290,7 @@ public class ClassWithResilientThenEmpty {
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @"$s16class_resilience26ClassWithResilientPropertyC5colors5Int32Vvg"(ptr swiftself %0)
 // CHECK:      [[OFFSET:%.*]] = load [[INT]], ptr @"$s16class_resilience26ClassWithResilientPropertyC5colors5Int32VvpWvd"
 // CHECK-NEXT: [[FIELD_ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[OFFSET]]
-// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_VALUE:%.*]] = load i32, ptr [[FIELD_PAYLOAD]]
 // CHECK: ret i32 [[FIELD_VALUE]]
 
@@ -299,7 +299,7 @@ public class ClassWithResilientThenEmpty {
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @"$s16class_resilience33ClassWithResilientlySizedPropertyC5colors5Int32Vvg"(ptr swiftself %0)
 // CHECK:      [[OFFSET:%.*]] = load [[INT]], ptr @"$s16class_resilience33ClassWithResilientlySizedPropertyC5colors5Int32VvpWvd"
 // CHECK-NEXT: [[FIELD_ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[OFFSET]]
-// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_VALUE:%.*]] = load i32, ptr [[FIELD_PAYLOAD]]
 // CHECK:      ret i32 [[FIELD_VALUE]]
 
@@ -307,8 +307,8 @@ public class ClassWithResilientThenEmpty {
 // ClassWithIndirectResilientEnum.color getter
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @"$s16class_resilience30ClassWithIndirectResilientEnumC5colors5Int32Vvg"(ptr swiftself %0)
-// CHECK:      [[FIELD_PTR:%.*]] = getelementptr inbounds %T16class_resilience30ClassWithIndirectResilientEnumC, ptr %0, i32 0, i32 2
-// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[FIELD_PTR]], i32 0, i32 0
+// CHECK:      [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %T16class_resilience30ClassWithIndirectResilientEnumC, ptr %0, i32 0, i32 2
+// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[FIELD_PTR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_VALUE:%.*]] = load i32, ptr [[FIELD_PAYLOAD]]
 // CHECK: ret i32 [[FIELD_VALUE]]
 
@@ -319,7 +319,7 @@ public class ClassWithResilientThenEmpty {
 // CHECK:      [[OFFSET:%.*]] = load [[INT]], ptr @"$s16class_resilience14ResilientChildC5fields5Int32VvpWvd"
 // CHECK-NEXT: [[FIELD_ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[OFFSET]]
 // CHECK: call void @swift_beginAccess
-// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_VALUE:%.*]] = load i32, ptr [[FIELD_PAYLOAD]]
 // CHECK-NEXT: call void @swift_endAccess
 // CHECK: ret i32 [[FIELD_VALUE]]
@@ -340,7 +340,7 @@ public class ClassWithResilientThenEmpty {
 // CHECK-NEXT: [[FIELD_OFFSET:%.*]] = load [[INT]], ptr [[FIELD_OFFSET_ADDR:%.*]]
 // CHECK-NEXT: [[ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[FIELD_OFFSET]]
 // CHECK:      call void @swift_beginAccess
-// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[RESULT:%.*]] = load i32, ptr [[PAYLOAD_ADDR]]
 // CHECK-NEXT: call void @swift_endAccess
 // CHECK:      ret i32 [[RESULT]]
@@ -349,8 +349,8 @@ public class ClassWithResilientThenEmpty {
 // MyResilientChild.field getter
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @"$s16class_resilience16MyResilientChildC5fields5Int32Vvg"(ptr swiftself %0)
-// CHECK:      [[FIELD_ADDR:%.*]] = getelementptr inbounds %T16class_resilience16MyResilientChildC, ptr %0, i32 0, i32 2
-// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK:      [[FIELD_ADDR:%.*]] = getelementptr inbounds{{.*}} %T16class_resilience16MyResilientChildC, ptr %0, i32 0, i32 2
+// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[RESULT:%.*]] = load i32, ptr [[PAYLOAD_ADDR]]
 // CHECK:      ret i32 [[RESULT]]
 
@@ -395,7 +395,7 @@ public class ClassWithResilientThenEmpty {
 // CHECK-objc-NEXT: [[FIELDS_DEST:%.*]] = getelementptr inbounds [[INT]], ptr %0, [[INT]] {{10|13}}
 // CHECK-native-NEXT: [[FIELDS_DEST:%.*]] = getelementptr inbounds [[INT]], ptr %0, [[INT]] {{7|10}}
 // CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 {{12|24}}, ptr [[FIELDS]])
-// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds [3 x ptr], ptr [[FIELDS]], i32 0, i32 0
+// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr [[FIELDS]], i32 0, i32 0
 
 // CHECK:      [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s16resilient_struct4SizeVMa"([[INT]] 319)
 // CHECK-NEXT: [[SIZE_METADATA:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
@@ -473,7 +473,7 @@ public class ClassWithResilientThenEmpty {
 // CHECK-objc-NEXT: [[FIELDS_DEST:%.*]] = getelementptr inbounds [[INT]], ptr %0, [[INT]] {{10|13}}
 // CHECK-native-NEXT: [[FIELDS_DEST:%.*]] = getelementptr inbounds [[INT]], ptr %0, [[INT]] {{7|10}}
 // CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 {{8|16}}, ptr [[FIELDS]])
-// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds [2 x ptr], ptr [[FIELDS]], i32 0, i32 0
+// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds{{.*}} [2 x ptr], ptr [[FIELDS]], i32 0, i32 0
 
 // CHECK:      [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s16resilient_struct9RectangleVMa"([[INT]] 319)
 // CHECK-NEXT: [[SIZE_METADATA:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
diff --git a/test/IRGen/class_resilience_objc.swift b/test/IRGen/class_resilience_objc.swift
index 6c3e22d52524e..a33ff54da89bf 100644
--- a/test/IRGen/class_resilience_objc.swift
+++ b/test/IRGen/class_resilience_objc.swift
@@ -37,7 +37,7 @@ public class FixedLayoutObjCSubclass : NSObject {
 // CHECK:      [[OFFSET:%.*]] = load [[INT]], ptr @"$s21class_resilience_objc23FixedLayoutObjCSubclassC5fields5Int32VvpWvd"
 // CHECK-NEXT: [[ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[OFFSET]]
 // CHECK:      call void @swift_beginAccess
-// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
 // CHECK-NEXT: store i32 10, ptr [[PAYLOAD_ADDR]]
 
 func testConstantDirectFieldAccess(_ o: FixedLayoutObjCSubclass) {
@@ -54,7 +54,7 @@ public class NonFixedLayoutObjCSubclass : NSCoder {
 // CHECK:      [[OFFSET:%.*]] = load [[INT]], ptr @"$s21class_resilience_objc26NonFixedLayoutObjCSubclassC5fields5Int32VvpWvd"
 // CHECK-NEXT: [[ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[OFFSET]]
 // CHECK:      call void @swift_beginAccess
-// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
 // CHECK-NEXT: store i32 10, ptr [[PAYLOAD_ADDR]]
 
 func testNonConstantDirectFieldAccess(_ o: NonFixedLayoutObjCSubclass) {
@@ -91,7 +91,7 @@ public class GenericObjCSubclass<T> : NSCoder {
 // CHECK-NEXT: [[FIELD_OFFSET:%.*]] = load [[INT]], ptr [[FIELD_OFFSET_ADDR:%.*]]
 // CHECK-NEXT: [[ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[FIELD_OFFSET]]
 // CHECK:      call void @swift_beginAccess
-// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
 // CHECK-NEXT: store i32 10, ptr [[PAYLOAD_ADDR]]
 
 func testConstantIndirectFieldAccess<T>(_ o: GenericObjCSubclass<T>) {
diff --git a/test/IRGen/class_resilience_objc_armv7k.swift b/test/IRGen/class_resilience_objc_armv7k.swift
index f9d6ff197a960..5eda41d6b853e 100644
--- a/test/IRGen/class_resilience_objc_armv7k.swift
+++ b/test/IRGen/class_resilience_objc_armv7k.swift
@@ -16,7 +16,7 @@ public class FixedLayoutObjCSubclass : NSObject {
 // CHECK:      [[OFFSET:%.*]] = load [[INT]], ptr @"$s28class_resilience_objc_armv7k23FixedLayoutObjCSubclassC5fields5Int32VvpWvd"
 // CHECK-NEXT: [[ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[OFFSET]]
 // CHECK:      call void @swift_beginAccess
-// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
 // CHECK-NEXT: store i32 10, ptr [[PAYLOAD_ADDR]]
 
 func testConstantDirectFieldAccess(_ o: FixedLayoutObjCSubclass) {
@@ -33,7 +33,7 @@ public class NonFixedLayoutObjCSubclass : NSCoder {
 // CHECK:      [[OFFSET:%.*]] = load [[INT]], ptr @"$s28class_resilience_objc_armv7k26NonFixedLayoutObjCSubclassC5fields5Int32VvpWvd"
 // CHECK-NEXT: [[ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[OFFSET]]
 // CHECK:      call void @swift_beginAccess
-// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
 // CHECK-NEXT: store i32 10, ptr [[PAYLOAD_ADDR]]
 
 func testNonConstantDirectFieldAccess(_ o: NonFixedLayoutObjCSubclass) {
@@ -60,7 +60,7 @@ public class GenericObjCSubclass<T> : NSCoder {
 // CHECK-NEXT: [[FIELD_OFFSET:%.*]] = load [[INT]], ptr [[FIELD_OFFSET_ADDR:%.*]]
 // CHECK-NEXT: [[ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[FIELD_OFFSET]]
 // CHECK:      call void @swift_beginAccess
-// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[ADDR]], i32 0, i32 0
 // CHECK-NEXT: store i32 10, ptr [[PAYLOAD_ADDR]]
 
 func testConstantIndirectFieldAccess<T>(_ o: GenericObjCSubclass<T>) {
diff --git a/test/IRGen/class_update_callback_with_fixed_layout.sil b/test/IRGen/class_update_callback_with_fixed_layout.sil
index 606f010a58762..c77c249a53814 100644
--- a/test/IRGen/class_update_callback_with_fixed_layout.sil
+++ b/test/IRGen/class_update_callback_with_fixed_layout.sil
@@ -179,7 +179,7 @@ bb0(%0 : $ClassWithResilientField):
 
 // CHECK:        [[OFFSET:%.*]] = load i64, ptr @"$s39class_update_callback_with_fixed_layout23ClassWithResilientFieldC5thirdSivpWvd", align 8
 // CHECK-NEXT:   [[FIELD_ADDR:%.*]] = getelementptr inbounds i8, ptr %0, i64 [[OFFSET]]
-// CHECK-NEXT:   [[FIELD_PTR:%.*]] = getelementptr inbounds %TSi, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK-NEXT:   [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[FIELD_ADDR]], i32 0, i32 0
 
   %1 = ref_element_addr %0 : $ClassWithResilientField, #ClassWithResilientField.third
 
@@ -208,7 +208,7 @@ bb0(%0 : $ClassWithResilientField):
 // CHECK-NEXT: [[FIELDS:%.*]] = alloca [3 x ptr]
 // CHECK-NEXT: [[FIELDS_DEST:%.*]] = getelementptr inbounds [[INT]], ptr %0, [[INT]] {{10|13}}
 // CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 {{12|24}}, ptr [[FIELDS]])
-// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds [3 x ptr], ptr [[FIELDS]], i32 0, i32 0
+// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr [[FIELDS]], i32 0, i32 0
 
 // CHECK:      [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s16resilient_struct4SizeVMa"([[INT]] 319)
 // CHECK-NEXT: [[SIZE_METADATA:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
@@ -252,7 +252,7 @@ bb0(%0 : $ClassWithResilientField):
 // CHECK-NEXT: [[FIELDS:%.*]] = alloca [0 x ptr]
 // CHECK-NEXT: [[FIELDS_DEST:%.*]] = getelementptr inbounds [[INT]], ptr %0, [[INT]] {{11|14}}
 // CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 0, ptr [[FIELDS]])
-// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds [0 x ptr], ptr [[FIELDS]], i32 0, i32 0
+// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds{{.*}} [0 x ptr], ptr [[FIELDS]], i32 0, i32 0
 
 // -- ClassLayoutFlags = 0x100 (HasStaticVTable)
 // CHECK:      [[T0:%.*]] = call swiftcc %swift.metadata_response @swift_updateClassMetadata2(ptr %0, [[INT]] 256, [[INT]] 0, ptr [[FIELDS_PTR]], ptr [[FIELDS_DEST]])
diff --git a/test/IRGen/class_update_callback_without_fixed_layout.sil b/test/IRGen/class_update_callback_without_fixed_layout.sil
index f7327307649bb..69cae19e1309a 100644
--- a/test/IRGen/class_update_callback_without_fixed_layout.sil
+++ b/test/IRGen/class_update_callback_without_fixed_layout.sil
@@ -185,7 +185,7 @@ bb0(%0 : $ClassWithResilientField):
 
 // CHECK:        [[OFFSET:%.*]] = load [[INT]], ptr @"$s42class_update_callback_without_fixed_layout23ClassWithResilientFieldC5thirdSivpWvd"
 // CHECK-NEXT:   [[FIELD_ADDR:%.*]] = getelementptr inbounds i8, ptr %0, [[INT]] [[OFFSET]]
-// CHECK-NEXT:   [[FIELD_PTR:%.*]] = getelementptr inbounds %TSi, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK-NEXT:   [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[FIELD_ADDR]], i32 0, i32 0
 
   %1 = ref_element_addr %0 : $ClassWithResilientField, #ClassWithResilientField.third
 
@@ -219,7 +219,7 @@ bb0(%0 : $ClassWithResilientField):
 // CHECK-64-NEXT: [[FIELDS_DEST:%.*]] = getelementptr inbounds [[INT]], ptr %0, [[INT]] 10
 // CHECK-32-NEXT: call void @llvm.lifetime.start.p0(i64 12, ptr [[FIELDS]])
 // CHECK-64-NEXT: call void @llvm.lifetime.start.p0(i64 24, ptr [[FIELDS]])
-// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds [3 x ptr], ptr [[FIELDS]], i32 0, i32 0
+// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr [[FIELDS]], i32 0, i32 0
 
 // CHECK:      [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s16resilient_struct4SizeVMa"([[INT]] 319)
 // CHECK-NEXT: [[SIZE_METADATA:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
@@ -265,7 +265,7 @@ bb0(%0 : $ClassWithResilientField):
 // CHECK-32-NEXT: [[FIELDS_DEST:%.*]] = getelementptr inbounds [[INT]], ptr %0, [[INT]] 17
 // CHECK-64-NEXT: [[FIELDS_DEST:%.*]] = getelementptr inbounds [[INT]], ptr %0, [[INT]] 14
 // CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 0, ptr [[FIELDS]])
-// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds [0 x ptr], ptr [[FIELDS]], i32 0, i32 0
+// CHECK-NEXT: [[FIELDS_PTR:%.*]] = getelementptr inbounds{{.*}} [0 x ptr], ptr [[FIELDS]], i32 0, i32 0
 
 // -- ClassLayoutFlags = 0x100 (HasStaticVTable)
 // CHECK-OLD:  [[T0:%.*]] = call swiftcc %swift.metadata_response @swift_initClassMetadata2(ptr %0, [[INT]] 256, [[INT]] 0, ptr [[FIELDS_PTR]], ptr [[FIELDS_DEST]])
diff --git a/test/IRGen/closure.swift b/test/IRGen/closure.swift
index 4e90114dfad26..d387eab8848af 100644
--- a/test/IRGen/closure.swift
+++ b/test/IRGen/closure.swift
@@ -36,7 +36,7 @@ func b<T : Ordinable>(seq seq: T) -> (Int) -> Int {
 // -- partial_apply stub
 // CHECK: define internal swiftcc i64 @"$s7closure1b3seqS2icx_tAA9OrdinableRzlFS2icfU_TA"(i64 %0, ptr swiftself %1) {{.*}} {
 // CHECK: entry:
-// CHECK:   [[BINDINGSADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted, [16 x i8] }>, ptr %1, i32 0, i32 1
+// CHECK:   [[BINDINGSADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [16 x i8] }>, ptr %1, i32 0, i32 1
 // CHECK:   [[TYPE:%.*]] = load ptr, ptr [[BINDINGSADDR]], align 8
 // CHECK:   [[WITNESSADDR:%.*]] = getelementptr inbounds ptr, ptr [[BINDINGSADDR]], i32 1
 // CHECK:   [[WITNESS:%.*]] = load ptr, ptr [[WITNESSADDR]], align 8
diff --git a/test/IRGen/condfail.sil b/test/IRGen/condfail.sil
index 3b48901a82da1..575fbd442bc99 100644
--- a/test/IRGen/condfail.sil
+++ b/test/IRGen/condfail.sil
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -primary-file %s -O -g -S  | %FileCheck %s --check-prefix CHECK --check-prefix CHECK-%target-cpu --check-prefix CHECK-OPT-%target-os
+// RUN: %target-swift-frontend -primary-file %s -O -g -S  | %FileCheck %s --check-prefix CHECK --check-prefix CHECK-%target-cpu --check-prefix CHECK-OPT-%target-os --check-prefix CHECK-OPT-%target-os-%target-cpu
 // RUN: %target-swift-frontend -primary-file %s -g -S  | %FileCheck %s --check-prefix CHECK --check-prefix CHECK-%target-cpu --check-prefix CHECK-NOOPT-%target-os
 
 import Builtin
@@ -25,8 +25,10 @@ import Swift
 // CHECK-OPT-windows:   ##NO_APP
 // CHECK-OPT-linux-androideabi:   @APP
 // CHECK-OPT-linux-androideabi:   @NO_APP
-// CHECK-OPT-linux-android:       //APP
-// CHECK-OPT-linux-android:       //NO_APP
+// CHECK-OPT-linux-android-aarch64:       //APP
+// CHECK-OPT-linux-android-aarch64:       //NO_APP
+// CHECK-OPT-linux-android-x86_64:       #APP
+// CHECK-OPT-linux-android-x86_64:       #NO_APP
 // CHECK-NOOPT-macosx-NOT: InlineAsm Start
 // CHECK-NOOPT-macosx-NOT: InlineAsm End
 // CHECK-NOOPT-linux-NOT:  ##APP
@@ -35,8 +37,10 @@ import Swift
 // CHECK-NOOPT-windows-NOT:  ##NO_APP
 // CHECK-OPT-linux-androideabi-NOT:   @APP
 // CHECK-OPT-linux-androideabi-NOT:   @NO_APP
-// CHECK-OPT-linux-android-NOT:       //APP
-// CHECK-OPT-linux-android-NOT:       //NO_APP
+// CHECK-OPT-linux-android-aarch64-NOT:       //APP
+// CHECK-OPT-linux-android-aarch64-NOT:       //NO_APP
+// CHECK-OPT-linux-android-x86_64-NOT:       #APP
+// CHECK-OPT-linux-android-x86_64-NOT:       #NO_APP
 // CHECK-x86_64:      ud2
 // CHECK-i386:        ud2
 // CHECK-arm64:       brk
@@ -46,15 +50,15 @@ import Swift
 // CHECK-powerpc64:   trap
 // CHECK-powerpc64le: trap
 // CHECK-s390x:       j       .Ltmp{{[0-9]+}}+2
-// CHECK-NOT-x86_64:      {{.cfi_endproc|Lfunc_end}}
-// CHECK-NOT-i386:        .cfi_endproc
-// CHECK-NOT-arm64:       .cfi_endproc
-// CHECK-NOT-aarch64:     .cfi_endproc
-// CHECK-NOT-armv7:       Lfunc_end
-// CHECK-NOT-armv7s:      Lfunc_end
-// CHECK-NOT-powerpc64:   .cfi_endproc
-// CHECK-NOT-powerpc64le: .cfi_endproc
-// CHECK-NOT-s390x:       .cfi_endproc
+// CHECK-x86_64-NOT:      {{.cfi_endproc|Lfunc_end}}
+// CHECK-i386-NOT:        .cfi_endproc
+// CHECK-arm64-NOT:       .cfi_endproc
+// CHECK-aarch64-NOT:     .cfi_endproc
+// CHECK-armv7-NOT:       Lfunc_end
+// CHECK-armv7s-NOT:      Lfunc_end
+// CHECK-powerpc64-NOT:   .cfi_endproc
+// CHECK-powerpc64le-NOT: .cfi_endproc
+// CHECK-s390x-NOT:       .cfi_endproc
 // CHECK-OPT-macosx:  InlineAsm Start
 // CHECK-OPT-macosx:  InlineAsm End
 // CHECK-OPT-linux:   ##APP
diff --git a/test/IRGen/condfail_message.swift b/test/IRGen/condfail_message.swift
index 7638aebaab18a..3dd0ba87f2801 100644
--- a/test/IRGen/condfail_message.swift
+++ b/test/IRGen/condfail_message.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend -primary-file %s -g -O -emit-ir | %FileCheck %s
 // REQUIRES: optimized_stdlib
 
-// CHECK-LABEL: define hidden swiftcc i8 @"$s16condfail_message6testitys4Int8VADF"(i8 %0)
+// CHECK-LABEL: define hidden swiftcc{{.*}} i8 @"$s16condfail_message6testitys4Int8VADF"(i8 %0)
 // CHECK: call void @llvm.trap(), !dbg [[LOC:![0-9]+]]
 
 func testit(_ a: Int8) -> Int8 {
diff --git a/test/IRGen/conditional_conformances_class_with_defaulted_method.swift b/test/IRGen/conditional_conformances_class_with_defaulted_method.swift
index 1118b4ba4803d..6b5334dc74ee3 100644
--- a/test/IRGen/conditional_conformances_class_with_defaulted_method.swift
+++ b/test/IRGen/conditional_conformances_class_with_defaulted_method.swift
@@ -12,4 +12,4 @@ extension Foo {
 }
 class Box<T> {}
 extension Box: Foo where T: Foo {}
-// CHECK-LABEL: define internal swiftcc void @"$s1x3BoxCyqd__GAA3FooA2aEP3baryyFTW"(ptr noalias nocapture swiftself dereferenceable({{[48]}}) %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define internal swiftcc void @"$s1x3BoxCyqd__GAA3FooA2aEP3baryyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{[48]}}) %0, ptr %Self, ptr %SelfWitnessTable)
diff --git a/test/IRGen/conformance_path_with_concrete_steps.swift b/test/IRGen/conformance_path_with_concrete_steps.swift
new file mode 100644
index 0000000000000..63978cbd5d2f0
--- /dev/null
+++ b/test/IRGen/conformance_path_with_concrete_steps.swift
@@ -0,0 +1,29 @@
+// RUN: %target-swift-frontend -emit-ir %s
+
+public protocol P1 {
+  associatedtype A: P3
+}
+
+public protocol P2: P1 where A.B == G<C> {
+  associatedtype C where C == A.B.C
+}
+
+public protocol P3 {
+  associatedtype B: P4
+}
+
+public protocol P4: P5 {}
+
+public protocol P5 {
+  associatedtype C: P6
+}
+
+public protocol P6 {
+  func foo()
+}
+
+public struct G<C: P6>: P4 {}
+
+public func f<T: P2>(_: T, c: T.C) {
+  return c.foo()
+}
diff --git a/test/IRGen/constant_struct_with_padding.sil b/test/IRGen/constant_struct_with_padding.sil
index 74c17e5f83457..ff7b99d2e6c45 100644
--- a/test/IRGen/constant_struct_with_padding.sil
+++ b/test/IRGen/constant_struct_with_padding.sil
@@ -11,7 +11,7 @@ struct T {
 }
 
 // CHECK: @global = hidden global %T4main1TV <{ i1 false, [3 x i8] undef, i32 0 }>, align 4
-sil_global hidden @global : $T = {
+sil_global hidden [used] @global : $T = {
   %2 = integer_literal $Builtin.Int1, 0
   %3 = integer_literal $Builtin.Int32, 0
   %initval = struct $T (%2 : $Builtin.Int1, %3 : $Builtin.Int32)
diff --git a/test/IRGen/coroutine_accessors.swift b/test/IRGen/coroutine_accessors.swift
index 457ff1dde130d..914a102153873 100644
--- a/test/IRGen/coroutine_accessors.swift
+++ b/test/IRGen/coroutine_accessors.swift
@@ -1,5 +1,6 @@
 // RUN: %target-swift-emit-irgen                                            \
 // RUN:     %s                                                              \
+// RUN:     -enable-callee-allocated-coro-abi                               \
 // RUN:     -enable-experimental-feature CoroutineAccessors                 \
 // RUN: | %IRGenFileCheck %s
 
@@ -97,7 +98,7 @@ public var irm: Int {
 // CHECK-SAME:                   ptr @"$s19coroutine_accessors1SV3irmSivyTwc",
 // CHECK-SAME:                   ptr [[ALLOCATOR]],
 // CHECK-SAME:                   ptr [[FRAME]],
-// CHECK-SAME:                   ptr @"$s19coroutine_accessors1SVSiIetMIgYy_TC",
+// CHECK-SAME:                   $s19coroutine_accessors1SVSiIetMIgYy_TC
 // CHECK-SAME:                   ptr @_swift_coro_alloc,
 // CHECK-SAME:                   ptr @_swift_coro_dealloc
 // CHECK-SAME:               )
@@ -125,7 +126,7 @@ public var irm: Int {
 // CHECK-LABEL:     define{{.*}} { ptr, ptr } @"$s19coroutine_accessors1SV3irmSivx"(
 // CHECK-SAME:          ptr noalias [[FRAME:%[^,]+]],
 // CHECK-SAME:          ptr swiftcoro [[ALLOCATOR:%[^,]+]],
-// CHECK-SAME:          ptr nocapture swiftself dereferenceable({{8|16}}) [[SELF:%[^)]+]]
+// CHECK-SAME:          ptr{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{8|16}}) [[SELF:%[^)]+]]
 // CHECK-SAME:      )
 // CHECK-SAME:      {
 // CHECK:               [[ID:%[^,]+]] = call token @llvm.coro.id.retcon.once.dynamic(
@@ -134,7 +135,7 @@ public var irm: Int {
 // CHECK-SAME:                   ptr @"$s19coroutine_accessors1SV3irmSivxTwc",
 // CHECK-SAME:                   ptr [[ALLOCATOR]],
 // CHECK-SAME:                   ptr [[FRAME]],
-// CHECK-SAME:                   ptr @"$s19coroutine_accessors1SVSiIetMIlYl_TC",
+// CHECK-SAME:                   $s19coroutine_accessors1SVSiIetMIlYl_TC
 // CHECK-SAME:                   ptr @_swift_coro_alloc,
 // CHECK-SAME:                   ptr @_swift_coro_dealloc
 // CHECK-SAME:               )
@@ -142,7 +143,7 @@ public var irm: Int {
 // CHECK-SAME:                   token [[ID]],
 // CHECK-SAME:                   ptr null
 // CHECK-SAME:               )
-// CHECK:               [[S_FIELD__I:%[^,]+]] = getelementptr inbounds %T19coroutine_accessors1SV,
+// CHECK:               [[S_FIELD__I:%[^,]+]] = getelementptr inbounds{{.*}} %T19coroutine_accessors1SV,
 // CHECK-SAME:                     ptr [[SELF]],
 // CHECK-SAME:                     i32 0,
 // CHECK-SAME:                     i32 1
@@ -230,7 +231,7 @@ public mutating func increment_irm() {
 // CHECK-SAME:        _swift_coro_async_allocator
 // CHECK-SAME:    )
 // CHECK:         call void @llvm.lifetime.end.p0(i64 -1, ptr [[FRAME]])
-// CHECK:         call swiftcc void @swift_task_dealloc_through(ptr [[FRAME]])
+// CHECK:         call swiftcc void @{{(_)?}}swift_task_dealloc_through(ptr [[FRAME]])
 // CHECK:       }
 @_silgen_name("increment_irm_async")
 public mutating func increment_irm_async() async {
@@ -292,7 +293,7 @@ public var force_yield_once_2_convention : () {
 // CHECK-LABEL: define{{.*}} { ptr, ptr } @increment_irm_yield_once_2(
 //                  ptr noalias %0
 // CHECK-SAME:      ptr swiftcoro [[ALLOCATOR:%[^,]+]]
-//                  ptr nocapture swiftself dereferenceable(16) %2
+//                  ptr{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(16) %2
 // CHECK-SAME:  )
 // CHECK-SAME:  {
 //      :         [[SIZE_32:%[^,]+]] = load i32
diff --git a/test/IRGen/coroutine_accessors_backdeploy_async_56.swift b/test/IRGen/coroutine_accessors_backdeploy_async_56.swift
new file mode 100644
index 0000000000000..53baa0977d44c
--- /dev/null
+++ b/test/IRGen/coroutine_accessors_backdeploy_async_56.swift
@@ -0,0 +1,264 @@
+// RUN: %target-swift-emit-irgen                                            \
+// RUN:     %s                                                              \
+// RUN:     -enable-callee-allocated-coro-abi                               \
+// RUN:     -module-name backdep                                            \
+// RUN:     -target %target-swift-5.6-abi-triple                            \
+// RUN:     -Onone                                                          \
+// RUN:     -enable-experimental-feature CoroutineAccessors                 \
+// RUN: | %IRGenFileCheck %s
+
+// REQUIRES: swift_stable_abi
+// REQUIRES: concurrency
+// REQUIRES: concurrency_runtime
+// REQUIRES: swift_feature_CoroutineAccessors
+
+// CHECK-LABEL: %swift.back_deploy.task.pre_57 = type {
+//                  object header
+// CHECK-SAME:      %swift.refcounted
+//                  Job.SchedulerPrivate
+// CHECK-SAME:      ptr, ptr
+//                  Job.Flags
+// CHECK-SAME:      i32
+//                  Job.ID
+// CHECK-SAME:      i32
+//                  Job.Voucher
+// CHECK-SAME:      ptr
+//                  Job.Reserved
+// CHECK-SAME:      ptr
+//                  Job.RunJob/Job.ResumeTask
+// CHECK-SAME:      ptr
+//                  Task.ResumeContext
+// CHECK-SAME:      ptr
+//                  #if SWIFT_POINTER_IS_8_BYTES
+//                  Task.Reserved64
+//                  #endif
+// CHECK-64-SAME:   ptr
+//                  Task.Status
+// CHECK-SAME:      [2 x ptr]
+// CHECK-SAME:      ptr
+// CHECK-SAME:  }
+
+// CHECK-64-LABEL: %swift.back_deploy.task.post_57 = type {
+//                     object header
+// CHECK-64-SAME:      %swift.refcounted
+//                     Job.SchedulerPrivate
+// CHECK-64-SAME:      ptr, ptr
+//                     Job.Flags
+// CHECK-64-SAME:      i32
+//                     Job.ID
+// CHECK-64-SAME:      i32
+//                     Job.Voucher
+// CHECK-64-SAME:      ptr
+//                     Job.Reserved
+// CHECK-64-SAME:      ptr
+//                     Job.RunJob/Job.ResumeTask
+// CHECK-64-SAME:      ptr
+//                     Task.ResumeContext
+// CHECK-64-SAME:      ptr
+//                     #if SWIFT_POINTER_IS_8_BYTES
+//                     Task.Reserved64
+//                     #endif
+// CHECK-64-SAME:      ptr
+//                     Task.ExclusivityAccessSet
+// CHECK-64-SAME:      [2 x [[INT]]]
+//                     Task.StatusStorage
+// CHECK-64-SAME:      [2 x ptr]
+// CHECK-64-SAME:      ptr
+// CHECK-64-SAME:  }
+
+// CHECK-32-LABEL: %swift.back_deploy.task.post_57.escalating = type {
+//                     object header
+// CHECK-32-SAME:      %swift.refcounted
+//                     Job.SchedulerPrivate
+// CHECK-32-SAME:      ptr, ptr
+//                     Job.Flags
+// CHECK-32-SAME:      i32
+//                     Job.ID
+// CHECK-32-SAME:      i32
+//                     Job.Voucher
+// CHECK-32-SAME:      ptr
+//                     Job.Reserved
+// CHECK-32-SAME:      ptr
+//                     Job.RunJob/Job.ResumeTask
+// CHECK-32-SAME:      ptr
+//                     Task.ResumeContext
+// CHECK-32-SAME:      ptr
+//                     Task.ExclusivityAccessSet
+// CHECK-32-SAME:      [2 x i32],
+//                     Task.StatusStorage
+// CHECK-32-SAME:      [4 x ptr],
+// CHECK-32-SAME:      ptr
+// CHECK-32-SAME:  }
+// CHECK-32-LABEL: %swift.back_deploy.task.post_57.nonescalating = type {
+//                     object header
+// CHECK-32-SAME:      %swift.refcounted
+//                     Job.SchedulerPrivate
+// CHECK-32-SAME:      ptr, ptr
+//                     Job.Flags
+// CHECK-32-SAME:      i32
+//                     Job.ID
+// CHECK-32-SAME:      i32
+//                     Job.Voucher
+// CHECK-32-SAME:      ptr
+//                     Job.Reserved
+// CHECK-32-SAME:      ptr
+//                     Job.RunJob/Job.ResumeTask
+// CHECK-32-SAME:      ptr
+//                     Task.ResumeContext
+// CHECK-32-SAME:      ptr
+//                     Task.ExclusivityAccessSet
+// CHECK-32-SAME:      [2 x i32],
+//                     Task.StatusStorage
+// CHECK-32-SAME:      [2 x ptr],
+// CHECK-32-SAME:      ptr
+// CHECK-32-SAME:  }
+public struct S {
+public var _i: Int = 0
+
+public var i: Int {
+  read {
+    yield _i
+  }
+  modify {
+    yield &_i
+  }
+}
+
+// CHECK-LABEL: define{{.*}} void @increment_i_async(
+//                  ptr swiftasync %0
+// CHECK-SAME:      ptr{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{8|4}}) %1
+// CHECK-SAME:  )
+// CHECK-SAME:  {
+//      :         [[SIZE_32:%[^,]+]] = load i32
+//           :        ptr getelementptr inbounds (
+//           :            %swift.coro_func_pointer
+// CHECK:                 $s7backdep1SV1iSivxTwc
+//           :            i32 0
+//           :            i32 1
+//           :        )
+// CHECK-64:      [[SIZE_64:%[^,]+]] = zext i32 {{%[^,]+}} to i64
+// CHECK-64:      [[SIZE_1:%[^,]+]] = add [[INT]] [[SIZE_64]], 15
+// CHECK-32:      [[SIZE_1:%[^,]+]] = add [[INT]] {{%[^,]+}}, 15
+// CHECK:         [[SIZE:%[^,]+]] = and [[INT]] [[SIZE_1]], -16
+// CHECK:         [[FRAME:%[^,]+]] = call swiftcc ptr @swift_task_alloc([[INT]] [[SIZE]])
+// CHECK:         call void @llvm.lifetime.start.p0(i64 -1, ptr [[FRAME]])
+// CHECK:         [[RAMP:%[^,]+]] = call ptr @llvm.coro.prepare.retcon(ptr @"$s7backdep1SV1iSivx")
+// CHECK:         [[RETVAL:%[^,]+]] = call swiftcc { ptr, ptr } [[RAMP]](
+// CHECK-SAME:         [[FRAME]]
+// CHECK-SAME:         _swift_coro_async_allocator
+// CHECK-SAME:         %1
+// CHECK-SAME:    )
+// CHECK:         [[CONTINUATION:%[^,]+]] = extractvalue { ptr, ptr } [[RETVAL]], 0
+// CHECK:         [[YIELD:%[^,]+]] = extractvalue { ptr, ptr } [[RETVAL]], 1
+
+//                increment_async([[YIELD]])
+
+// CHECK:         call swiftcc void [[CONTINUATION]](
+// CHECK-SAME:        [[FRAME]],
+// CHECK-SAME:        _swift_coro_async_allocator
+// CHECK-SAME:    )
+// CHECK:         call void @llvm.lifetime.end.p0(i64 -1, ptr [[FRAME]])
+// CHECK:         call swiftcc void @_swift_task_dealloc_through(ptr [[FRAME]])
+// CHECK:       }
+@_silgen_name("increment_i_async")
+public mutating func increment_i_async() async {
+  await increment_async(&i)
+}
+}
+
+public func increment_async(_ int: inout Int) async {
+  int += 1
+}
+
+// CHECK-LABEL: define{{.*}} void @_swift_task_dealloc_through(
+// CHECK-SAME:      ptr [[FINAL_ALLOCATED_MEMORY:%[^)]+]]
+// CHECK-SAME:  )
+// CHECK-SAME:  {
+// CHECK:       entry:
+// CHECK:         [[HAS_RUNTIME_SYMBOL:%[^,]+]] = icmp ne ptr @swift_task_dealloc_through, null
+// CHECK:         br i1 [[HAS_RUNTIME_SYMBOL]]
+// CHECK-SAME:        label %runtime_symbol
+// CHECK-SAME:        label %no_runtime_symbol
+// CHECK:       runtime_symbol:
+// CHECK:         call swiftcc void @swift_task_dealloc_through(ptr [[FINAL_ALLOCATED_MEMORY]])
+// CHECK:         ret void
+// CHECK:       no_runtime_symbol:
+// CHECK:         [[TASK:%[^,]+]] = call swiftcc ptr @swift_task_getCurrent()
+// CHECK:         [[IS_AT_LEAST_VALUE:%[^,]+]] = call i32 @__isPlatformVersionAtLeast
+// CHECK:         [[IS_AT_LEAST:%[^,]+]] = icmp ne i32 [[IS_AT_LEAST_VALUE]], 0
+// CHECK:         br i1 [[IS_AT_LEAST]]
+// CHECK-SAME:        label %new_layout
+// CHECK-SAME:        label %old_layout
+// CHECK:       old_layout:
+// CHECK:         [[OLD_ADDR:%[^,]+]] = getelementptr inbounds
+// CHECK-SAME:        %swift.back_deploy.task.pre_57
+// CHECK-SAME:        ptr [[TASK]]
+// CHECK-SAME:        i32 0
+// CHECK-64-SAME:     i32 11
+// CHECK-32-SAME:     i32 10
+// CHECK:         br label %merge_layout
+
+// CHECK-64:    new_layout:
+// CHECK-64:      [[NEW_ADDR:%[^,]+]] = getelementptr inbounds
+// CHECK-64-SAME:     %swift.back_deploy.task.post_57
+// CHECK-64-SAME:     ptr [[TASK]]
+// CHECK-64-SAME:     i32 0
+// CHECK-64-SAME:     i32 12
+// CHECK-64:      br label %merge_layout
+
+// CHECK-32:    new_layout:
+// CHECK-32:      [[ESCALATION_IS_DEFINED:%[^,]+]] = icmp ne ptr @_swift_concurrency_debug_supportsPriorityEscalation, null
+// CHECK-32:      br i1 [[ESCALATION_IS_DEFINED]]
+// CHECK-32-SAME:     label %escalation_has_symbol
+// CHECK-32-SAME:     label %escalation_no
+// CHECK-32:    escalation_has_symbol:
+// CHECK-32:      [[ESCALATION:%[^,]+]] = load i8, ptr @_swift_concurrency_debug_supportsPriorityEscalation
+// CHECK-32:      [[ESCALATION_IS_TRUE:%[^,]+]] = icmp ne i8 [[ESCALATION]], 0
+// CHECK-32:      br i1 [[ESCALATION_IS_TRUE]]
+// CHECK-32-SAME:     label %escalation_yes
+// CHECK-32-SAME:     label %escalation_no
+// CHECK-32:    escalation_yes:
+// CHECK-32:      [[YES_ADDR:%[^,]+]] = getelementptr inbounds
+// CHECK-32-SAME:     %swift.back_deploy.task.post_57.escalating
+// CHECK-32-SAME:     ptr [[TASK]]
+// CHECK-32-SAME:     i32 0
+// CHECK-32-SAME:     i32 11
+// CHECK-32:      br label %escalation_merge
+// CHECK-32:    escalation_no:
+// CHECK-32:      [[NO_ADDR:%[^,]+]] = getelementptr inbounds
+// CHECK-32-SAME:     %swift.back_deploy.task.post_57.nonescalating
+// CHECK-32-SAME:     ptr [[TASK]]
+// CHECK-32-SAME:     i32 0
+// CHECK-32-SAME:     i32 11
+// CHECK-32:      br label %escalation_merge
+// CHECK-32:    escalation_merge:
+// CHECK-32:      [[NEW_ADDR:%[^,]+]] = phi ptr
+// CHECK-32-SAME:     [ [[NO_ADDR]], %escalation_no ]
+// CHECK-32-SAME:     [ [[YES_ADDR]], %escalation_yes ]
+// CHECK-32:      br label %merge_layout
+
+// CHECK:       merge_layout:
+// CHECK:         [[ALLOCATION_ADDR_ADDR:%[^,]+]] = phi ptr
+// CHECK-SAME:        [ [[OLD_ADDR]], %old_layout ]
+// CHECK-64-SAME:     [ [[NEW_ADDR]], %new_layout ]
+// CHECK-32-SAME:     [ [[NEW_ADDR]], %escalation_merge ]
+// CHECK:         br label %loop
+// CHECK:       loop:
+// CHECK:         [[ALLOCATION_ADDR:%[^,]+]] = load ptr
+// CHECK-SAME:        ptr [[ALLOCATION_ADDR_ADDR]]
+// CHECK:         [[ALLOCATED_MEMORY:%[^,]+]] = getelementptr inbounds i8
+// CHECK-SAME:        ptr [[ALLOCATION_ADDR]]
+// CHECK-SAME:        [[INT]] 16
+// CHECK:         call swiftcc void @swift_task_dealloc(
+// CHECK-SAME:        ptr [[ALLOCATED_MEMORY]]
+// CHECK-SAME:    )
+// CHECK:         [[WAS_FINAL:%[^,]+]] = icmp ne ptr
+// CHECK-SAME:        [[ALLOCATED_MEMORY]]
+// CHECK-SAME:        [[FINAL_ALLOCATED_MEMORY]]
+// CHECK:         br i1 [[WAS_FINAL]]
+// CHECK-SAME:        label %loop
+// CHECK-SAME:        label %exit
+// CHECK:       exit:
+// CHECK:         ret void
+// CHECK:       }
+
diff --git a/test/IRGen/coroutine_accessors_backdeploy_async_57.swift b/test/IRGen/coroutine_accessors_backdeploy_async_57.swift
new file mode 100644
index 0000000000000..725bcf2bbca50
--- /dev/null
+++ b/test/IRGen/coroutine_accessors_backdeploy_async_57.swift
@@ -0,0 +1,216 @@
+// RUN: %target-swift-emit-irgen                                            \
+// RUN:     %s                                                              \
+// RUN:     -enable-callee-allocated-coro-abi                               \
+// RUN:     -module-name backdep                                            \
+// RUN:     -target %target-swift-5.7-abi-triple                            \
+// RUN:     -Onone                                                          \
+// RUN:     -enable-experimental-feature CoroutineAccessors                 \
+// RUN: | %IRGenFileCheck %s
+
+// REQUIRES: swift_stable_abi
+// REQUIRES: concurrency
+// REQUIRES: concurrency_runtime
+// REQUIRES: swift_feature_CoroutineAccessors
+
+// CHECK-64-LABEL: %swift.back_deploy.task.post_57 = type {
+//                     object header
+// CHECK-64-SAME:      %swift.refcounted
+//                     Job.SchedulerPrivate
+// CHECK-64-SAME:      ptr, ptr
+//                     Job.Flags
+// CHECK-64-SAME:      i32
+//                     Job.ID
+// CHECK-64-SAME:      i32
+//                     Job.Voucher
+// CHECK-64-SAME:      ptr
+//                     Job.Reserved
+// CHECK-64-SAME:      ptr
+//                     Job.RunJob/Job.ResumeTask
+// CHECK-64-SAME:      ptr
+//                     Task.ResumeContext
+// CHECK-64-SAME:      ptr
+//                     #if SWIFT_POINTER_IS_8_BYTES
+//                     Task.Reserved64
+//                     #endif
+// CHECK-64-SAME:      ptr
+//                     Task.ExclusivityAccessSet
+// CHECK-64-SAME:      [2 x [[INT]]]
+//                     Task.StatusStorage
+// CHECK-64-SAME:      [2 x ptr]
+// CHECK-64-SAME:      ptr
+// CHECK-64-SAME:  }
+
+// CHECK-32-LABEL: %swift.back_deploy.task.post_57.escalating = type {
+//                     object header
+// CHECK-32-SAME:      %swift.refcounted
+//                     Job.SchedulerPrivate
+// CHECK-32-SAME:      ptr, ptr
+//                     Job.Flags
+// CHECK-32-SAME:      i32
+//                     Job.ID
+// CHECK-32-SAME:      i32
+//                     Job.Voucher
+// CHECK-32-SAME:      ptr
+//                     Job.Reserved
+// CHECK-32-SAME:      ptr
+//                     Job.RunJob/Job.ResumeTask
+// CHECK-32-SAME:      ptr
+//                     Task.ResumeContext
+// CHECK-32-SAME:      ptr
+//                     Task.ExclusivityAccessSet
+// CHECK-32-SAME:      [2 x i32],
+//                     Task.StatusStorage
+// CHECK-32-SAME:      [4 x ptr],
+// CHECK-32-SAME:      ptr
+// CHECK-32-SAME:  }
+// CHECK-32-LABEL: %swift.back_deploy.task.post_57.nonescalating = type {
+//                     object header
+// CHECK-32-SAME:      %swift.refcounted
+//                     Job.SchedulerPrivate
+// CHECK-32-SAME:      ptr, ptr
+//                     Job.Flags
+// CHECK-32-SAME:      i32
+//                     Job.ID
+// CHECK-32-SAME:      i32
+//                     Job.Voucher
+// CHECK-32-SAME:      ptr
+//                     Job.Reserved
+// CHECK-32-SAME:      ptr
+//                     Job.RunJob/Job.ResumeTask
+// CHECK-32-SAME:      ptr
+//                     Task.ResumeContext
+// CHECK-32-SAME:      ptr
+//                     Task.ExclusivityAccessSet
+// CHECK-32-SAME:      [2 x i32],
+//                     Task.StatusStorage
+// CHECK-32-SAME:      [2 x ptr],
+// CHECK-32-SAME:      ptr
+// CHECK-32-SAME:  }
+
+public struct S {
+public var _i: Int = 0
+
+public var i: Int {
+  read {
+    yield _i
+  }
+  modify {
+    yield &_i
+  }
+}
+
+// CHECK-LABEL: define{{.*}} void @increment_i_async(
+//                  ptr swiftasync %0
+// CHECK-SAME:      ptr{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{8|4}}) %1
+// CHECK-SAME:  )
+// CHECK-SAME:  {
+//      :         [[SIZE_32:%[^,]+]] = load i32
+//           :        ptr getelementptr inbounds (
+//           :            %swift.coro_func_pointer
+// CHECK:                 $s7backdep1SV1iSivxTwc
+//           :            i32 0
+//           :            i32 1
+//           :        )
+// CHECK-64:      [[SIZE_64:%[^,]+]] = zext i32 {{%[^,]+}} to i64
+// CHECK-64:      [[SIZE_1:%[^,]+]] = add [[INT]] [[SIZE_64]], 15
+// CHECK-32:      [[SIZE_1:%[^,]+]] = add [[INT]] {{%[^,]+}}, 15
+// CHECK:         [[SIZE:%[^,]+]] = and [[INT]] [[SIZE_1]], -16
+// CHECK:         [[FRAME:%[^,]+]] = call swiftcc ptr @swift_task_alloc([[INT]] [[SIZE]])
+// CHECK:         call void @llvm.lifetime.start.p0(i64 -1, ptr [[FRAME]])
+// CHECK:         [[RAMP:%[^,]+]] = call ptr @llvm.coro.prepare.retcon(ptr @"$s7backdep1SV1iSivx")
+// CHECK:         [[RETVAL:%[^,]+]] = call swiftcc { ptr, ptr } [[RAMP]](
+// CHECK-SAME:         [[FRAME]]
+// CHECK-SAME:         _swift_coro_async_allocator
+// CHECK-SAME:         %1
+// CHECK-SAME:    )
+// CHECK:         [[CONTINUATION:%[^,]+]] = extractvalue { ptr, ptr } [[RETVAL]], 0
+// CHECK:         [[YIELD:%[^,]+]] = extractvalue { ptr, ptr } [[RETVAL]], 1
+
+//                increment_async([[YIELD]])
+
+// CHECK:         call swiftcc void [[CONTINUATION]](
+// CHECK-SAME:        [[FRAME]],
+// CHECK-SAME:        _swift_coro_async_allocator
+// CHECK-SAME:    )
+// CHECK:         call void @llvm.lifetime.end.p0(i64 -1, ptr [[FRAME]])
+// CHECK:         call swiftcc void @_swift_task_dealloc_through(ptr [[FRAME]])
+// CHECK:       }
+@_silgen_name("increment_i_async")
+public mutating func increment_i_async() async {
+  await increment_async(&i)
+}
+}
+
+public func increment_async(_ int: inout Int) async {
+  int += 1
+}
+
+// CHECK-LABEL: define{{.*}} void @_swift_task_dealloc_through(
+// CHECK-SAME:      ptr [[FINAL_ALLOCATED_MEMORY:%[^)]+]]
+// CHECK-SAME:  )
+// CHECK-SAME:  {
+// CHECK:       entry:
+// CHECK:         [[HAS_RUNTIME_SYMBOL:%[^,]+]] = icmp ne ptr @swift_task_dealloc_through, null
+// CHECK:         br i1 [[HAS_RUNTIME_SYMBOL]]
+// CHECK-SAME:        label %runtime_symbol
+// CHECK-SAME:        label %no_runtime_symbol
+// CHECK:       runtime_symbol:
+// CHECK:         call swiftcc void @swift_task_dealloc_through(ptr [[FINAL_ALLOCATED_MEMORY]])
+// CHECK:         ret void
+// CHECK:       no_runtime_symbol:
+// CHECK:         [[TASK:%[^,]+]] = call swiftcc ptr @swift_task_getCurrent()
+
+// CHECK-64:      [[ALLOCATION_ADDR_ADDR:%[^,]+]] = getelementptr inbounds
+// CHECK-64-SAME:     %swift.back_deploy.task.post_57
+// CHECK-64-SAME:     ptr [[TASK]],
+// CHECK-64-SAME:     i32 0
+// CHECK-64-SAME:     i32 12
+
+// CHECK-32:      [[ESCALATION_IS_DEFINED:%[^,]+]] = icmp ne ptr @_swift_concurrency_debug_supportsPriorityEscalation, null
+// CHECK-32:      br i1 [[ESCALATION_IS_DEFINED]]
+// CHECK-32-SAME:     label %escalation_has_symbol
+// CHECK-32-SAME:     label %escalation_no
+// CHECK-32:    escalation_has_symbol:
+// CHECK-32:      [[ESCALATION:%[^,]+]] = load i8, ptr @_swift_concurrency_debug_supportsPriorityEscalation
+// CHECK-32:      [[ESCALATION_IS_TRUE:%[^,]+]] = icmp ne i8 [[ESCALATION]], 0
+// CHECK-32:      br i1 [[ESCALATION_IS_TRUE]]
+// CHECK-32-SAME:     label %escalation_yes
+// CHECK-32-SAME:     label %escalation_no
+// CHECK-32:    escalation_yes:
+// CHECK-32:      [[YES_ADDR:%[^,]+]] = getelementptr inbounds
+// CHECK-32-SAME:     %swift.back_deploy.task.post_57.escalating
+// CHECK-32-SAME:     ptr [[TASK]]
+// CHECK-32-SAME:     i32 0
+// CHECK-32-SAME:     i32 11
+// CHECK-32:      br label %escalation_merge
+// CHECK-32:    escalation_no:
+// CHECK-32:      [[NO_ADDR:%[^,]+]] = getelementptr inbounds
+// CHECK-32-SAME:     %swift.back_deploy.task.post_57.nonescalating
+// CHECK-32-SAME:     ptr [[TASK]]
+// CHECK-32-SAME:     i32 0
+// CHECK-32-SAME:     i32 11
+// CHECK-32:      br label %escalation_merge
+// CHECK-32:    escalation_merge:
+// CHECK-32:      [[ALLOCATION_ADDR_ADDR:%[^,]+]] = phi ptr
+// CHECK-32-SAME:     [ [[NO_ADDR]], %escalation_no ]
+// CHECK-32-SAME:     [ [[YES_ADDR]], %escalation_yes ]
+
+// CHECK:         br label %loop
+// CHECK:       loop:
+// CHECK:         [[ALLOCATION_ADDR:%[^,]+]] = load ptr
+// CHECK-SAME:        ptr [[ALLOCATION_ADDR_ADDR]]
+// CHECK:         [[ALLOCATED_MEMORY:%[^,]+]] = getelementptr inbounds i8
+// CHECK-SAME:        ptr [[ALLOCATION_ADDR]]
+// CHECK-SAME:        [[INT]] 16
+// CHECK:         call swiftcc void @swift_task_dealloc(
+// CHECK-SAME:        ptr [[ALLOCATED_MEMORY]]
+// CHECK-SAME:    )
+// CHECK:         [[WAS_FINAL:%[^,]+]] = icmp ne ptr
+// CHECK-SAME:        [[ALLOCATED_MEMORY]]
+// CHECK-SAME:        [[FINAL_ALLOCATED_MEMORY]]
+// CHECK:         br i1 [[WAS_FINAL]]
+// CHECK-SAME:        label %loop
+// CHECK-SAME:        label %exit
+// CHECK:       exit:
+// CHECK:         ret void
+// CHECK:       }
diff --git a/test/IRGen/coroutine_accessors_popless.swift b/test/IRGen/coroutine_accessors_popless.swift
index 1109656a7a3d8..38db9436ea82e 100644
--- a/test/IRGen/coroutine_accessors_popless.swift
+++ b/test/IRGen/coroutine_accessors_popless.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-emit-irgen                                            \
 // RUN:     %s                                                              \
 // RUN:     -Onone                                                          \
+// RUN:     -enable-callee-allocated-coro-abi                               \
 // RUN:     -enable-experimental-feature CoroutineAccessors                 \
 // RUN:     -enable-arm64-corocc                                            \
 // RUN:     -enable-x86_64-corocc                                           \
@@ -174,7 +175,7 @@ public func increment(_ int: inout Int) {
 // CHECK-SAME:        _swift_coro_async_allocator
 // CHECK-SAME:    )
 // CHECK:         call void @llvm.lifetime.end.p0(i64 -1, ptr [[FRAME]])
-// CHECK:         call swiftcc void @swift_task_dealloc_through(ptr [[FRAME]])
+// CHECK:         call swiftcc void @{{(_)?}}swift_task_dealloc_through(ptr [[FRAME]])
 // CHECK:       }
 @_silgen_name("increment_i_async")
 public func increment_i_async() async {
diff --git a/test/IRGen/default_override.sil b/test/IRGen/default_override.sil
index ccf09349c6c6e..88c4fe6e4cb00 100644
--- a/test/IRGen/default_override.sil
+++ b/test/IRGen/default_override.sil
@@ -1,5 +1,6 @@
 // RUN: %target-swift-frontend \
 // RUN:     %s \
+// RUN:     -enable-callee-allocated-coro-abi \
 // RUN:     -module-name Library \
 // RUN:     -emit-ir \
 // RUN:     -enable-experimental-feature CoroutineAccessors \
diff --git a/test/IRGen/dependent_reabstraction.swift b/test/IRGen/dependent_reabstraction.swift
index c0250b8f00b17..c3d632b97f86a 100644
--- a/test/IRGen/dependent_reabstraction.swift
+++ b/test/IRGen/dependent_reabstraction.swift
@@ -8,7 +8,7 @@ protocol A {
 }
 
 struct X<Y> : A {
-  // CHECK-LABEL: define internal swiftcc void @"$s23dependent_reabstraction1XVyxGAA1AA2aEP1byy1BQzFTW"(ptr noalias nocapture dereferenceable({{.*}}) %0, ptr noalias nocapture swiftself %1, ptr %Self, ptr %SelfWitnessTable)
+  // CHECK-LABEL: define internal swiftcc void @"$s23dependent_reabstraction1XVyxGAA1AA2aEP1byy1BQzFTW"(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %1, ptr %Self, ptr %SelfWitnessTable)
   func b(_ b: X.Type) {
     let x: Any = b
     markUsed(b as X.Type)
diff --git a/test/IRGen/dllexport.swift b/test/IRGen/dllexport.swift
index f63059353e44c..a05e1d8566f36 100644
--- a/test/IRGen/dllexport.swift
+++ b/test/IRGen/dllexport.swift
@@ -21,24 +21,21 @@ open class d {
   }
 }
 
+// CHECK-OPT-NOT: @"$s9dllexport1dCACycfc"
+
 // CHECK-DAG: @"$s9dllexport2ciAA1cCvp" = dllexport global ptr null
 // CHECK-DAG: @"$s9dllexport1pMp" = dllexport constant
 // CHECK-DAG: @"$s9dllexport1cCMn" = dllexport constant
 // CHECK-DAG: @"$s9dllexport1cCN" = dllexport alias %swift.type
 // CHECK-DAG: @"$s9dllexport1dCN" = dllexport alias %swift.type
-// CHECK-DAG-OPT: @"$s9dllexport1dC1m33_C57BA610BA35E21738CC992438E660E9LLs5NeverOyf" = dllexport alias void (), ptr @_swift_dead_method_stub
-// CHECK-DAG-OPT: @"$s9dllexport1dCACycfc" = dllexport alias void (), ptr @_swift_dead_method_stub
-// CHECK-DAG-OPT: @"$s9dllexport1cCACycfc" = dllexport alias void (), ptr @_swift_dead_method_stub
-// CHECK-DAG-OPT: @"$s9dllexport1cCACycfC" = dllexport alias void (), ptr @_swift_dead_method_stub
+// CHECK-OPT-DAG: @"$s9dllexport1dC1m33_C57BA610BA35E21738CC992438E660E9LLs5NeverOyF" = dllexport alias void (), ptr @_swift_dead_method_stub
 // CHECK-DAG: define dllexport swiftcc ptr @"$s9dllexport1cCfd"(ptr{{.*}})
-// CHECK-DAG-NO-OPT: define dllexport swiftcc ptr @"$s9dllexport1cCACycfc"(ptr %0)
-// CHECK-DAG-NO-OPT: define dllexport swiftcc ptr @"$s9dllexport1cCACycfC"(ptr %0)
+// CHECK-DAG: define dllexport swiftcc ptr @"$s9dllexport1cCACycfc"(ptr{{.*}} swiftself{{.*}} %0)
+// CHECK-DAG: define dllexport swiftcc {{(noalias )?}}ptr @"$s9dllexport1cCACycfC"(ptr swiftself %0)
 // CHECK-DAG: define dllexport swiftcc {{(noundef )?(nonnull )?}}ptr @"$s9dllexport2ciAA1cCvau"()
-// CHECK-DAG-NO-OPT: define dllexport swiftcc void @"$s9dllexport1dC1m33_C57BA610BA35E21738CC992438E660E9LLs5NeverOyF"(ptr %0)
-// CHECK-DAG-NO-OPT: define dllexport swiftcc void @"$s9dllexport1dCfD"(ptr %0)
+// CHECK-NO-OPT-DAG: define dllexport swiftcc void @"$s9dllexport1dC1m33_C57BA610BA35E21738CC992438E660E9LLs5NeverOyF"(ptr swiftself %0)
+// CHECK-DAG: define dllexport swiftcc void @"$s9dllexport1dCfD"(ptr swiftself %0)
 // CHECK-DAG: define dllexport swiftcc ptr @"$s9dllexport1dCfd"(ptr{{.*}})
 // CHECK-DAG: define dllexport swiftcc %swift.metadata_response @"$s9dllexport1cCMa"(i64 %0)
 // CHECK-DAG: define dllexport swiftcc %swift.metadata_response @"$s9dllexport1dCMa"(i64 %0)
-// CHECK-DAG-NO-OPT: define dllexport swiftcc ptr @"$s9dllexport1dCACycfc"(ptr %0)
-// CHECK-DAG-OPT: define dllexport swiftcc void @"$s9dllexport1dCfD"(ptr %0)
-
+// CHECK-NO-OPT-DAG: define hidden swiftcc ptr @"$s9dllexport1dCACycfc"(ptr swiftself %0)
diff --git a/test/IRGen/dynamic_replaceable.sil b/test/IRGen/dynamic_replaceable.sil
index 9e4022a38ee77..339bf7bc8e93c 100644
--- a/test/IRGen/dynamic_replaceable.sil
+++ b/test/IRGen/dynamic_replaceable.sil
@@ -24,7 +24,7 @@
 // CHECK: @"\01l_auto_dynamic_replacements" = private constant { i32, i32, [2 x i32] }
 // CHECK-SAME: { i32 0, i32 1,
 // CHECK-SAME: [2 x i32] [{{.*}}@"\01l_unnamed_dynamic_replacements"{{.*}}, i32 0]
-// CHECK-SAME: }, section "__TEXT, __swift5_replace, regular, no_dead_strip"
+// CHECK-SAME: }, section "__TEXT, __swift5_replace, regular, no_dead_strip", no_sanitize_address
 
 // CHECK-LABEL: define swiftcc void @test_dynamically_replaceable()
 // CHECK-NEXT: entry:
diff --git a/test/IRGen/dynamic_self_cast.swift b/test/IRGen/dynamic_self_cast.swift
index da6e67d24372a..3a703cf8e677e 100644
--- a/test/IRGen/dynamic_self_cast.swift
+++ b/test/IRGen/dynamic_self_cast.swift
@@ -35,7 +35,7 @@ public class SelfCasts {
   }
 
   // CHECK-LABEL: define {{(dllexport )?}}{{(protected )?}}swiftcc ptr @"$s17dynamic_self_cast9SelfCastsC016classGenericFromD0xyRlzClFZ"(ptr %T, ptr swiftself %0)
-  // CHECK: call zeroext i1 @swift_dynamicCast(ptr {{%.*}}, ptr {{%.*}}, ptr %0, ptr %T, {{.*}})
+  // CHECK: call ptr @swift_dynamicCastUnknownClassUnconditional(ptr {{%.*}}, ptr %T, ptr null, i32 0, i32 0)
   // CHECK: ret
   public static func classGenericFromSelf<T : AnyObject>() -> T {
     let s = Self()
@@ -72,7 +72,7 @@ public class SelfCasts {
   }
 
   // CHECK-LABEL: define {{(dllexport )?}}{{(protected )?}}swiftcc {{i32|i64}} @"$s17dynamic_self_cast9SelfCastsC016classGenericFromD11ConditionalxSgyRlzClFZ"(ptr %T, ptr swiftself %0)
-  // CHECK: call zeroext i1 @swift_dynamicCast(ptr {{%.*}}, ptr {{%.*}}, ptr %0, ptr %T, {{.*}})
+  // CHECK: call ptr @swift_dynamicCastUnknownClass(ptr {{%.*}}, ptr %T)
   // CHECK: ret
   public static func classGenericFromSelfConditional<T : AnyObject>() -> T? {
     let s = Self()
diff --git a/test/IRGen/empty_array.sil b/test/IRGen/empty_array.sil
index 11abdee3367cb..4cac39aac0f55 100644
--- a/test/IRGen/empty_array.sil
+++ b/test/IRGen/empty_array.sil
@@ -15,11 +15,11 @@ sil_stage canonical
 
 import Builtin
 
-// CHECK-32-LABEL: define{{( protected)?}} void @empty_array(%swift.opaque* noalias nocapture) {{.*}} {
+// CHECK-32-LABEL: define{{( protected)?}} void @empty_array(%swift.opaque* noalias {{(nocapture|captures\(none\))}}) {{.*}} {
 // CHECK-32:         %1 = bitcast %swift.opaque* %0 to i8*
 // CHECK-32:         %2 = getelementptr inbounds i8, i8* %1, i32 0
 
-// CHECK-64-LABEL: define{{( protected)?}} void @empty_array(%swift.opaque* noalias nocapture) {{.*}} {
+// CHECK-64-LABEL: define{{( protected)?}} void @empty_array(%swift.opaque* noalias {{(nocapture|captures\(none\))}}) {{.*}} {
 // CHECK-64:         %1 = bitcast %swift.opaque* %0 to i8*
 // CHECK-64:         %2 = getelementptr inbounds i8, i8* %1, i64 0
 
diff --git a/test/IRGen/enum.sil b/test/IRGen/enum.sil
index 22ad8968aa9cd..e153a0dfb97cd 100644
--- a/test/IRGen/enum.sil
+++ b/test/IRGen/enum.sil
@@ -238,7 +238,7 @@ dest(%u2 : $(Builtin.Int64, Builtin.Int64)):
   return %x : $()
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @singleton_switch_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @singleton_switch_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK: entry:
 // CHECK:   br label %[[DEST:[0-9]+]]
 // CHECK: [[DEST]]:
@@ -274,11 +274,11 @@ entry(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
   return %u : $Singleton
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @singleton_inject_indirect(i64 %0, i64 %1, ptr nocapture dereferenceable({{.*}}) %2) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @singleton_inject_indirect(i64 %0, i64 %1, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %2) {{.*}} {
 // CHECK: entry:
-// CHECK:   [[DATA_0_ADDR:%.*]] = getelementptr inbounds <{ i64, i64 }>, ptr %2, i32 0, i32 0
+// CHECK:   [[DATA_0_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ i64, i64 }>, ptr %2, i32 0, i32 0
 // CHECK:   store i64 %0, ptr [[DATA_0_ADDR]]
-// CHECK:   [[DATA_1_ADDR:%.*]] = getelementptr inbounds <{ i64, i64 }>, ptr %2, i32 0, i32 1
+// CHECK:   [[DATA_1_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ i64, i64 }>, ptr %2, i32 0, i32 1
 // CHECK:   store i64 %1, ptr [[DATA_1_ADDR]]
 // CHECK:   ret void
 // CHECK: }
@@ -349,10 +349,10 @@ end:
   return %x : $()
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @no_payload_switch_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @no_payload_switch_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 sil @no_payload_switch_indirect : $@convention(thin) (@inout NoPayloads) -> () {
 entry(%u : $*NoPayloads):
-// CHECK:   [[TAG_ADDR:%.*]] = getelementptr inbounds %T4enum10NoPayloadsO, ptr %0, i32 0, i32 0
+// CHECK:   [[TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T4enum10NoPayloadsO, ptr %0, i32 0, i32 0
 // CHECK:   [[TAG:%.*]] = load i8, ptr [[TAG_ADDR]]
 // CHECK:   switch i8 [[TAG]]
   switch_enum_addr %u : $*NoPayloads, case #NoPayloads.x!enumelt: x_dest, case #NoPayloads.y!enumelt: y_dest, case #NoPayloads.z!enumelt: z_dest
@@ -398,9 +398,9 @@ entry:
   return %u : $NoPayloads
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @no_payload_inject_z_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @no_payload_inject_z_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK: entry:
-// CHECK:   [[TAG_ADDR:%.*]] = getelementptr inbounds %T4enum10NoPayloadsO, ptr %0, i32 0, i32 0
+// CHECK:   [[TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T4enum10NoPayloadsO, ptr %0, i32 0, i32 0
 // CHECK:   store i8 2, ptr [[TAG_ADDR]]
 // CHECK:   ret void
 // CHECK: }
@@ -470,10 +470,10 @@ enum SinglePayloadNoXI2 {
 // CHECK-32: define{{( dllexport)?}}{{( protected)?}} swiftcc i1 @select_enum([[WORD:i32]] %0, i8 %1)
 // CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc i1 @select_enum([[WORD:i64]] %0, i8 %1)
 // CHECK: entry:
-// CHECK:   [[TAG:%.*]] = trunc i8 %1 to i1
 // CHECK:   [[PAYLOAD:%.*]] = icmp eq [[WORD]] %0, 1
-// CHECK:   [[MATCHES:%.*]] = and i1 [[TAG]], [[PAYLOAD]]
-// CHECK:   [[RES:%.*]] = select i1 [[MATCHES]], i1 false, i1 true
+// CHECK:   [[TAG:%.*]] = icmp eq i8 %1, 1
+// CHECK:   [[COMBINED:%.*]] = and i1 [[TAG]], [[PAYLOAD]]
+// CHECK:   [[RES:%.*]] = select i1 [[COMBINED]], i1 false, i1 true
 // CHECK:   ret i1 [[RES]]
 // CHECK: }
 
@@ -490,7 +490,7 @@ bb0(%0 : $SinglePayloadNoXI2):
 sil @single_payload_no_xi_switch : $@convention(thin) (SinglePayloadNoXI2) -> () {
 // CHECK: entry:
 entry(%u : $SinglePayloadNoXI2):
-// CHECK:   %2 = trunc i8
+// CHECK:   %2 = icmp eq i8 %1, 1
 // CHECK:   br i1 %2, label %[[TAGS:[0-9]+]], label %[[X_DEST:[0-9]+]]
 // CHECK: [[TAGS]]:
 // CHECK:   switch [[WORD]] %0, label %[[DFLT:[0-9]+]] [
@@ -564,7 +564,7 @@ end:
 sil @single_payload_no_xi_switch_arg : $@convention(thin) (SinglePayloadNoXI2) -> () {
 // CHECK: entry:
 entry(%u : $SinglePayloadNoXI2):
-// CHECK:  %2 = trunc i8
+// CHECK:   %2 = icmp eq i8 %1, 1
 // CHECK:   br i1 %2, label %[[TAGS:[0-9]+]], label %[[X_PREDEST:[0-9]+]]
 // CHECK: [[TAGS]]:
 // CHECK:   switch [[WORD]] %0, label %[[DFLT:[0-9]+]] [
@@ -629,11 +629,11 @@ entry(%0 : $Builtin.Word):
   return %u : $SinglePayloadNoXI2
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_no_xi_inject_x_indirect([[WORD]] %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_no_xi_inject_x_indirect([[WORD]] %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK: entry:
 // CHECK:   store [[WORD]] %0, ptr %1
-// CHECK:   [[T0:%.*]] = getelementptr inbounds %T4enum18SinglePayloadNoXI2O, ptr %1, i32 0, i32 1
-// CHECK:   store i1 false, ptr [[T0]]
+// CHECK:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T4enum18SinglePayloadNoXI2O, ptr %1, i32 0, i32 1
+// CHECK:   store i8 0, ptr [[T0]]
 // CHECK:   ret void
 // CHECK: }
 sil @single_payload_no_xi_inject_x_indirect : $(Builtin.Word, @inout SinglePayloadNoXI2) -> () {
@@ -655,11 +655,11 @@ entry:
   return %u : $SinglePayloadNoXI2
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_no_xi_inject_y_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_no_xi_inject_y_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK: entry:
 // CHECK:   store [[WORD]] 0, ptr %0
-// CHECK:   [[T0:%.*]] = getelementptr inbounds %T4enum18SinglePayloadNoXI2O, ptr %0, i32 0, i32 1
-// CHECK:   store i1 true, ptr [[T0]]
+// CHECK:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T4enum18SinglePayloadNoXI2O, ptr %0, i32 0, i32 1
+// CHECK:   store i8 1, ptr [[T0]]
 // CHECK:   ret void
 // CHECK: }
 sil @single_payload_no_xi_inject_y_indirect : $(@inout SinglePayloadNoXI2) -> () {
@@ -992,7 +992,7 @@ entry(%0 : $Builtin.Int63):
   return %u : $SinglePayloadSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_spare_bit_inject_x_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_spare_bit_inject_x_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[T:%.*]] = trunc i64 %0 to i63
 // CHECK-64:   [[BYTE:%.*]] = zext i63 [[T]] to i64
@@ -1019,7 +1019,7 @@ entry:
   return %u : $SinglePayloadSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_spare_bit_inject_y_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_spare_bit_inject_y_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // --                0x8000_0000_0000_0000
 // CHECK-64:   store i64 -9223372036854775808, ptr %0
@@ -1304,7 +1304,7 @@ end(%z : $()):
   return %z : $()
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc i8 @dynamic_single_payload_empty_payload_load(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc i8 @dynamic_single_payload_empty_payload_load(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK: entry:
 // CHECK:   %1 = load i8, ptr %0
 // CHECK:   ret i8 %1
@@ -1315,7 +1315,7 @@ entry(%p : $*DynamicSinglePayload<()>):
   return %x : $DynamicSinglePayload<()>
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @dynamic_single_payload_empty_payload_store(ptr nocapture dereferenceable({{.*}}) %0, i8 %1) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @dynamic_single_payload_empty_payload_store(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, i8 %1) {{.*}} {
 // CHECK: entry:
 // CHECK:   store i8 %1, ptr %0
 // CHECK:   ret void
@@ -1440,11 +1440,11 @@ end:
   return %v : $()
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bits_switch_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bits_switch_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 sil @multi_payload_no_spare_bits_switch_indirect : $(@inout MultiPayloadNoSpareBits) -> () {
 entry(%u : $*MultiPayloadNoSpareBits):
 // CHECK-64:   [[PAYLOAD:%.*]] = load i64, ptr %0
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T4enum23MultiPayloadNoSpareBitsO, ptr %0, i32 0, i32 1
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T4enum23MultiPayloadNoSpareBitsO, ptr %0, i32 0, i32 1
 // CHECK-64:   [[TAG:%.*]] = load i8, ptr [[T0]]
 // CHECK-64:   switch i8 [[TAG]]
 // CHECK-64:   switch i64 [[PAYLOAD]]
@@ -1494,10 +1494,10 @@ entry(%0 : $Builtin.Int64):
   return %u : $MultiPayloadNoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bit_inject_x_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bit_inject_x_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   store i64 %0, ptr %1
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T4enum23MultiPayloadNoSpareBitsO, ptr %1, i32 0, i32 1
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T4enum23MultiPayloadNoSpareBitsO, ptr %1, i32 0, i32 1
 // CHECK-64:   store i8 0, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
@@ -1547,10 +1547,10 @@ entry:
   return %u : $MultiPayloadNoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bit_inject_a_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bit_inject_a_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   store i64 0, ptr %0
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T4enum23MultiPayloadNoSpareBitsO, ptr %0, i32 0, i32 1
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T4enum23MultiPayloadNoSpareBitsO, ptr %0, i32 0, i32 1
 // CHECK-64:   store i8 3, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
@@ -1593,12 +1593,10 @@ enum MultiPayloadOneSpareBit {
 // CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_switch(i64 %0, i8 %1) {{.*}} {
 sil @multi_payload_one_spare_bit_switch : $(MultiPayloadOneSpareBit) -> () {
 entry(%u : $MultiPayloadOneSpareBit):
-// CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i8 %1 to i1
 // CHECK-64:   [[SPARE_TAG_LSHR:%.*]] = lshr i64 %0, 63
 // CHECK-64:   [[SPARE_TAG_TRUNC:%.*]] = trunc i64 [[SPARE_TAG_LSHR]] to i8
 // CHECK-64:   [[SPARE_TAG:%.*]] = and i8 [[SPARE_TAG_TRUNC]], 1
-// CHECK-64:   [[EXTRA_TAG_ZEXT:%.*]] = zext i1 [[NATIVECC_TRUNC]] to i8
-// CHECK-64:   [[EXTRA_TAG:%.*]] = shl i8 [[EXTRA_TAG_ZEXT]], 1
+// CHECK-64:   [[EXTRA_TAG:%.*]] = shl i8 %1, 1
 // CHECK-64:   [[TAG:%.*]] = or i8 [[SPARE_TAG]], [[EXTRA_TAG]]
 // CHECK-64:   switch i8 [[TAG]], label %[[UNREACHABLE:[0-9]+]] [
 // CHECK-64:     i8 0, label %[[X_PREDEST:[0-9]+]]
@@ -1680,8 +1678,8 @@ end:
 sil @multi_payload_one_spare_bit_switch_indirect : $(@inout MultiPayloadOneSpareBit) -> () {
 entry(%u : $*MultiPayloadOneSpareBit):
 // CHECK-64:   [[PAYLOAD:%.*]] = load i64, ptr %0
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T4enum23MultiPayloadOneSpareBitO, ptr %0, i32 0, i32 1
-// CHECK-64:   [[TAG:%.*]] = load i1, ptr [[T0]]
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T4enum23MultiPayloadOneSpareBitO, ptr %0, i32 0, i32 1
+// CHECK-64:   [[TAG:%.*]] = load i8, ptr [[T0]]
 // CHECK-64:   switch i8 {{%.*}}
 // CHECK-64:   switch i64 [[PAYLOAD]]
 // CHECK-64: {{[0-9]+}}:
@@ -1738,7 +1736,7 @@ entry(%0 : $Builtin.Int62):
   return %u : $MultiPayloadOneSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_x_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_x_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i64 %0 to i62
 // CHECK-64:   [[BYTE:%.*]] = zext i62 [[NATIVECC_TRUNC]] to i64
@@ -1747,8 +1745,8 @@ entry(%0 : $Builtin.Int62):
 // --                                                   0x7FFF_FFFF_FFFF_FFFF
 // CHECK-64:   [[PAYLOAD_MASKED:%.*]] = and i64 [[PAYLOAD]], 9223372036854775807
 // CHECK-64:   store i64 [[PAYLOAD_MASKED]], ptr %1
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T4enum23MultiPayloadOneSpareBitO, ptr %1, i32 0, i32 1
-// CHECK-64:   store i1 false, ptr [[T0]]
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T4enum23MultiPayloadOneSpareBitO, ptr %1, i32 0, i32 1
+// CHECK-64:   store i8 0, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
 sil @multi_payload_one_spare_bit_inject_x_indirect : $(Builtin.Int62, @inout MultiPayloadOneSpareBit) -> () {
@@ -1776,7 +1774,7 @@ entry(%0 : $Builtin.Int63):
   return %u : $MultiPayloadOneSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_y_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_y_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i64 %0 to i63
 // CHECK-64:   [[BYTE:%.*]] = zext i63 [[NATIVECC_TRUNC]] to i64
@@ -1787,8 +1785,8 @@ entry(%0 : $Builtin.Int63):
 // --                                                          0x8000_0000_0000_0000
 // CHECK-64:   [[PAYLOAD_TAGGED:%.*]] = or i64 [[PAYLOAD_MASKED]], -9223372036854775808
 // CHECK-64:   store i64 [[PAYLOAD_TAGGED]], ptr %1
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T4enum23MultiPayloadOneSpareBitO, ptr %1, i32 0, i32 1
-// CHECK-64:   store i1 false, ptr [[T0]]
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T4enum23MultiPayloadOneSpareBitO, ptr %1, i32 0, i32 1
+// CHECK-64:   store i8 0, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
 
@@ -1826,12 +1824,12 @@ entry:
   return %u : $MultiPayloadOneSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_a_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_a_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // --                0x8000_0000_0000_0000
 // CHECK-64:   store i64 -9223372036854775808, ptr %0
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T4enum23MultiPayloadOneSpareBitO, ptr %0, i32 0, i32 1
-// CHECK-64:   store i1 true, ptr [[T0]]
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T4enum23MultiPayloadOneSpareBitO, ptr %0, i32 0, i32 1
+// CHECK-64:   store i8 1, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
 sil @multi_payload_one_spare_bit_inject_a_indirect : $(@inout MultiPayloadOneSpareBit) -> () {
@@ -1970,7 +1968,7 @@ entry(%0 : $Builtin.Int62):
   return %u : $MultiPayloadTwoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_x_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_x_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i64 %0 to i62
 // CHECK-64:   [[BYTE:%.*]] = zext i62 [[NATIVECC_TRUNC]] to i64
@@ -2004,7 +2002,7 @@ entry(%0 : $Builtin.Int60):
   return %u : $MultiPayloadTwoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_y_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_y_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i64 %0 to i60
 // CHECK-64:   [[BYTE:%.*]] = zext i60 [[NATIVECC_TRUNC]] to i64
@@ -2051,7 +2049,7 @@ entry:
   return %u : $MultiPayloadTwoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_a_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_a_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // --                0xC000_0000_0000_0000
 // CHECK-64:   store i64 -4611686018427387904, ptr %0
@@ -2227,8 +2225,9 @@ enum MultiPayloadNested {
 // CHECK:   %3 = getelementptr
 // CHECK:   %4 = load i8, ptr %3
 // CHECK:   %5 = lshr i8 %4, 7
-// CHECK:   %6 = trunc i8 %5 to i1
-// CHECK:   br i1 %6
+// CHECK:   %6 = and i8 %5, 1
+// CHECK:   %7 = icmp ne i8 %6, 1
+// CHECK:   br i1 %7
 sil @multi_payload_nested_switch : $(@in MultiPayloadNested) -> () {
 entry(%c : $*MultiPayloadNested):
   switch_enum_addr %c : $*MultiPayloadNested, case #MultiPayloadNested.A!enumelt: a_dest, case #MultiPayloadNested.B!enumelt: b_dest
@@ -2255,12 +2254,14 @@ enum MultiPayloadNestedSpareBits {
   case B(MultiPayloadInnerSpareBits)
 }
 
-// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_nested_spare_bits_switch(ptr noalias nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_nested_spare_bits_switch(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   %1 = load [[WORD]], ptr %0
 // CHECK-64:   %2 = lshr [[WORD]] %1, 61
-// CHECK-64:   %3 = trunc [[WORD]] %2 to i1
-// CHECK-64:   br i1 %3
+// CHECK-64:   %3 = trunc [[WORD]] %2 to i8
+// CHECK-64:   %4 = and i8 %3, 1
+// CHECK-64:   %5 = icmp ne i8 %4, 1
+// CHECK-64:   br i1 %5
 sil @multi_payload_nested_spare_bits_switch : $(@in MultiPayloadNestedSpareBits) -> () {
 entry(%c : $*MultiPayloadNestedSpareBits):
   switch_enum_addr %c : $*MultiPayloadNestedSpareBits, case #MultiPayloadNestedSpareBits.A!enumelt: a_dest, case #MultiPayloadNestedSpareBits.B!enumelt: b_dest
@@ -2325,7 +2326,7 @@ enum MultiPayloadAddressOnlyFixed {
   case Y(Builtin.Int32)
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_address_only_destroy(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_address_only_destroy(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 sil @multi_payload_address_only_destroy : $@convention(thin) (@in MultiPayloadAddressOnlyFixed) -> () {
 entry(%m : $*MultiPayloadAddressOnlyFixed):
   destroy_addr %m : $*MultiPayloadAddressOnlyFixed
@@ -2459,7 +2460,7 @@ entry(%x : $Int32):
   // CHECK-64: [[INT_ZEXT:%.*]] = zext i32 %0 to i64
   // CHECK-64: [[INT_SHL:%.*]] = shl i64 [[INT_ZEXT]], 32
   %d = enum $Optional<(Optional<()>, Int32)>, #Optional.some!enumelt, %c : $(Optional<()>, Int32)
-  // CHECK-64: [[BIT:%.*]] = trunc i64 [[INT_SHL]] to i1
+  // CHECK-64: [[BIT:%.*]] = trunc i64 [[INT_SHL]] to i8
   // CHECK-64: [[INT_SHR:%.*]] = lshr i64 [[INT_SHL]], 32
   // CHECK-64: [[INT:%.*]] = trunc i64 [[INT_SHR]] to i32
   %e = unchecked_enum_data %d : $Optional<(Optional<()>, Int32)>, #Optional.some!enumelt
@@ -2611,11 +2612,11 @@ entry(%x : $*MyOptional):
 // CHECK:   [[T_VWT:%.*]] = load ptr, ptr [[T_VWT_ADDR]]
 // CHECK:   [[T_LAYOUT:%.*]] = getelementptr inbounds ptr, ptr [[T_VWT]], i32 8
 // CHECK:   call void @swift_initEnumMetadataSingleCase(ptr [[METADATA]], [[WORD]] 0, ptr [[T_LAYOUT]])
-// CHECK:   [[PAYLOAD_EXTRAINHABITANTCNT:%.*]] = getelementptr inbounds %swift.type_layout, ptr [[T_LAYOUT]], i32 0, i32 3
+// CHECK:   [[PAYLOAD_EXTRAINHABITANTCNT:%.*]] = getelementptr inbounds{{.*}} %swift.type_layout, ptr [[T_LAYOUT]], i32 0, i32 3
 // CHECK:   [[CNT:%.*]] = load i32, ptr [[PAYLOAD_EXTRAINHABITANTCNT]]
 // CHECK:   [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[METADATA]], [[WORD]] -1
 // CHECK:   [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
-// CHECK:   [[XIC_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 11
+// CHECK:   [[XIC_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 11
 // CHECK:   store i32 [[CNT]], ptr [[XIC_ADDR]]
 // CHECK:   ret %swift.metadata_response
 
diff --git a/test/IRGen/enum_copy_init_with_take_memcpy.swift b/test/IRGen/enum_copy_init_with_take_memcpy.swift
index 20e1880f92828..c551986294f3c 100644
--- a/test/IRGen/enum_copy_init_with_take_memcpy.swift
+++ b/test/IRGen/enum_copy_init_with_take_memcpy.swift
@@ -28,11 +28,11 @@ struct HasAnEnum {
 
 
 // CHECK: define {{.*}} swiftcc range(i64 -1, 5) i64 @"$s31enum_copy_init_with_take_memcpy9HasAnEnumV9readValueSiyF"(ptr {{.*}} %0)
-// CHECK:  [[T0:%.*]] = getelementptr inbounds i8, ptr %0, i64 160
+// CHECK:  [[T0:%.*]] = getelementptr inbounds{{.*}} i8, ptr %0, i64 160
 // CHECK:  [[T1:%.*]] = load i8, ptr [[T0]]
-// CHECK:  [[T2:%.*]] = icmp eq i8 [[T1]], 2
-// CHECK:  br i1 [[T2]], label
-// CHECK:  [[R:%.*]] = phi i64 [ -1, {{.*}} ], [ 4, {{.*}} ]
+// CHECK:  [[T2:%.*]] = and i8 [[T1]], -3
+// CHECK:  [[T3:%.*]] = icmp eq i8 [[T2]], 0
+// CHECK:  [[R:%.*]] = select i1 [[T3]], i64 -1, i64 4
 // CHECK:  ret i64 [[R]]
 
 }
diff --git a/test/IRGen/enum_derived.swift b/test/IRGen/enum_derived.swift
index 02f91193ec81d..314caae306ca6 100644
--- a/test/IRGen/enum_derived.swift
+++ b/test/IRGen/enum_derived.swift
@@ -48,8 +48,8 @@ extension def_enum.TrafficLight : Error {}
 
 extension def_enum.Term : Error {}
 
-// CHECK-NORMAL-LABEL: define hidden {{.*}}i64 @"$s12enum_derived7PhantomO8rawValues5Int64Vvg"(i8 %0, ptr nocapture readnone %T) local_unnamed_addr
-// CHECK-TESTABLE-LABEL: define{{( dllexport)?}}{{( protected)?}} {{.*}}i64 @"$s12enum_derived7PhantomO8rawValues5Int64Vvg"(i8 %0, ptr nocapture readnone %T)
+// CHECK-NORMAL-LABEL: define hidden {{.*}}i64 @"$s12enum_derived7PhantomO8rawValues5Int64Vvg"(i8 %0, ptr{{( nocapture)?}} readnone{{( captures\(none\))?}} %T) local_unnamed_addr
+// CHECK-TESTABLE-LABEL: define{{( dllexport)?}}{{( protected)?}} {{.*}}i64 @"$s12enum_derived7PhantomO8rawValues5Int64Vvg"(i8 %0, ptr{{( nocapture)?}} readnone{{( captures\(none\))?}} %T)
 
 enum Phantom<T> : Int64 {
   case Up
diff --git a/test/IRGen/enum_dynamic_multi_payload.sil b/test/IRGen/enum_dynamic_multi_payload.sil
index e6bf169be26ba..c781f99866a65 100644
--- a/test/IRGen/enum_dynamic_multi_payload.sil
+++ b/test/IRGen/enum_dynamic_multi_payload.sil
@@ -40,21 +40,21 @@ entry(%e : $Either<(), ()>):
   fix_lifetime %e : $Either<(), ()>
 
   // CHECK-NEXT: alloca
-  // CHECK-NEXT: trunc i8 {{.*}} to i1
   // CHECK-NEXT: llvm.lifetime.start
   %s = alloc_stack $Either<(), ()>
 
   %l = enum $Either<(), ()>, #Either.Left!enumelt, undef : $()
-  // CHECK-NEXT: store i1 false
+  // CHECK-NEXT: store i8 0
   store %l to %s : $*Either<(), ()>
   %r = enum $Either<(), ()>, #Either.Right!enumelt, undef : $()
-  // CHECK-NEXT: store i1 true
+  // CHECK-NEXT: store i8 1
+  // CHECK-NEXT: [[COND:%.*]] = icmp ne i8 {{%.*}}, 1
   store %r to %s : $*Either<(), ()>
 
   %a = unchecked_enum_data %l : $Either<(), ()>, #Either.Left!enumelt
   %b = unchecked_enum_data %r : $Either<(), ()>, #Either.Right!enumelt
 
-  // CHECK-NEXT: br i1 {{%.*}}, label %[[RIGHT_PRE:[0-9]+]], label %[[LEFT_PRE:[0-9]+]]
+  // CHECK-NEXT: br i1 [[COND]], label %[[LEFT_PRE:[0-9]+]], label %[[RIGHT_PRE:[0-9]+]]
   // CHECK:      [[LEFT_PRE]]:
   // CHECK:        br label [[LEFT:%[0-9]+]]
   // CHECK:      [[RIGHT_PRE]]:
diff --git a/test/IRGen/enum_future.sil b/test/IRGen/enum_future.sil
index 0418359d96bcf..5e24750fcfc9d 100644
--- a/test/IRGen/enum_future.sil
+++ b/test/IRGen/enum_future.sil
@@ -242,7 +242,7 @@ dest(%u2 : $(Builtin.Int64, Builtin.Int64)):
   return %x : $()
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @singleton_switch_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @singleton_switch_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK: entry:
 // CHECK:   br label %[[DEST:[0-9]+]]
 // CHECK: [[DEST]]:
@@ -278,11 +278,11 @@ entry(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
   return %u : $Singleton
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @singleton_inject_indirect(i64 %0, i64 %1, ptr nocapture dereferenceable({{.*}}) %2) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @singleton_inject_indirect(i64 %0, i64 %1, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %2) {{.*}} {
 // CHECK: entry:
-// CHECK:   [[DATA_0_ADDR:%.*]] = getelementptr inbounds <{ i64, i64 }>, ptr %2, i32 0, i32 0
+// CHECK:   [[DATA_0_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ i64, i64 }>, ptr %2, i32 0, i32 0
 // CHECK:   store i64 %0, ptr [[DATA_0_ADDR]]
-// CHECK:   [[DATA_1_ADDR:%.*]] = getelementptr inbounds <{ i64, i64 }>, ptr %2, i32 0, i32 1
+// CHECK:   [[DATA_1_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ i64, i64 }>, ptr %2, i32 0, i32 1
 // CHECK:   store i64 %1, ptr [[DATA_1_ADDR]]
 // CHECK:   ret void
 // CHECK: }
@@ -353,10 +353,10 @@ end:
   return %x : $()
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @no_payload_switch_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @no_payload_switch_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 sil @no_payload_switch_indirect : $@convention(thin) (@inout NoPayloads) -> () {
 entry(%u : $*NoPayloads):
-// CHECK:   [[TAG_ADDR:%.*]] = getelementptr inbounds %T11enum_future10NoPayloadsO, ptr %0, i32 0, i32 0
+// CHECK:   [[TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T11enum_future10NoPayloadsO, ptr %0, i32 0, i32 0
 // CHECK:   [[TAG:%.*]] = load i8, ptr [[TAG_ADDR]]
 // CHECK:   switch i8 [[TAG]]
   switch_enum_addr %u : $*NoPayloads, case #NoPayloads.x!enumelt: x_dest, case #NoPayloads.y!enumelt: y_dest, case #NoPayloads.z!enumelt: z_dest
@@ -402,9 +402,9 @@ entry:
   return %u : $NoPayloads
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @no_payload_inject_z_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @no_payload_inject_z_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK: entry:
-// CHECK:   [[TAG_ADDR:%.*]] = getelementptr inbounds %T11enum_future10NoPayloadsO, ptr %0, i32 0, i32 0
+// CHECK:   [[TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T11enum_future10NoPayloadsO, ptr %0, i32 0, i32 0
 // CHECK:   store i8 2, ptr [[TAG_ADDR]]
 // CHECK:   ret void
 // CHECK: }
@@ -474,8 +474,8 @@ enum SinglePayloadNoXI2 {
 // CHECK-32: define{{( dllexport)?}}{{( protected)?}} swiftcc i1 @select_enum([[WORD:i32]] %0, i8 %1)
 // CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc i1 @select_enum([[WORD:i64]] %0, i8 %1)
 // CHECK: entry:
-// CHECK:   [[TAG:%.*]] = trunc i8 %1 to i1
 // CHECK:   [[PAYLOAD:%.*]] = icmp eq [[WORD]] %0, 1
+// CHECK:   [[TAG:%.*]] = icmp eq i8 %1, 1
 // CHECK:   [[MATCHES:%.*]] = and i1 [[TAG]], [[PAYLOAD]]
 // CHECK:   [[RES:%.*]] = select i1 [[MATCHES]], i1 false, i1 true
 // CHECK:   ret i1 [[RES]]
@@ -494,7 +494,7 @@ bb0(%0 : $SinglePayloadNoXI2):
 sil @single_payload_no_xi_switch : $@convention(thin) (SinglePayloadNoXI2) -> () {
 // CHECK: entry:
 entry(%u : $SinglePayloadNoXI2):
-// CHECK:   %2 = trunc i8
+// CHECK:   %2 = icmp eq i8 %1, 1
 // CHECK:   br i1 %2, label %[[TAGS:[0-9]+]], label %[[X_DEST:[0-9]+]]
 // CHECK: [[TAGS]]:
 // CHECK:   switch [[WORD]] %0, label %[[DFLT:[0-9]+]] [
@@ -568,7 +568,7 @@ end:
 sil @single_payload_no_xi_switch_arg : $@convention(thin) (SinglePayloadNoXI2) -> () {
 // CHECK: entry:
 entry(%u : $SinglePayloadNoXI2):
-// CHECK:  %2 = trunc i8
+// CHECK:  %2 = icmp eq i8 %1, 1
 // CHECK:   br i1 %2, label %[[TAGS:[0-9]+]], label %[[X_PREDEST:[0-9]+]]
 // CHECK: [[TAGS]]:
 // CHECK:   switch [[WORD]] %0, label %[[DFLT:[0-9]+]] [
@@ -633,11 +633,11 @@ entry(%0 : $Builtin.Word):
   return %u : $SinglePayloadNoXI2
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_no_xi_inject_x_indirect([[WORD]] %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_no_xi_inject_x_indirect([[WORD]] %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK: entry:
 // CHECK:   store [[WORD]] %0, ptr %1
-// CHECK:   [[T0:%.*]] = getelementptr inbounds %T11enum_future18SinglePayloadNoXI2O, ptr %1, i32 0, i32 1
-// CHECK:   store i1 false, ptr [[T0]]
+// CHECK:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T11enum_future18SinglePayloadNoXI2O, ptr %1, i32 0, i32 1
+// CHECK:   store i8 0, ptr [[T0]]
 // CHECK:   ret void
 // CHECK: }
 sil @single_payload_no_xi_inject_x_indirect : $(Builtin.Word, @inout SinglePayloadNoXI2) -> () {
@@ -659,11 +659,11 @@ entry:
   return %u : $SinglePayloadNoXI2
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_no_xi_inject_y_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_no_xi_inject_y_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK: entry:
 // CHECK:   store [[WORD]] 0, ptr %0
-// CHECK:   [[T0:%.*]] = getelementptr inbounds %T11enum_future18SinglePayloadNoXI2O, ptr %0, i32 0, i32 1
-// CHECK:   store i1 true, ptr [[T0]]
+// CHECK:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T11enum_future18SinglePayloadNoXI2O, ptr %0, i32 0, i32 1
+// CHECK:   store i8 1, ptr [[T0]]
 // CHECK:   ret void
 // CHECK: }
 sil @single_payload_no_xi_inject_y_indirect : $(@inout SinglePayloadNoXI2) -> () {
@@ -996,7 +996,7 @@ entry(%0 : $Builtin.Int63):
   return %u : $SinglePayloadSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_spare_bit_inject_x_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_spare_bit_inject_x_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[T:%.*]] = trunc i64 %0 to i63
 // CHECK-64:   [[BYTE:%.*]] = zext i63 [[T]] to i64
@@ -1023,7 +1023,7 @@ entry:
   return %u : $SinglePayloadSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_spare_bit_inject_y_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @single_payload_spare_bit_inject_y_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // --                0x8000_0000_0000_0000
 // CHECK-64:   store i64 -9223372036854775808, ptr %0
@@ -1308,7 +1308,7 @@ end(%z : $()):
   return %z : $()
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc i8 @dynamic_single_payload_empty_payload_load(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc i8 @dynamic_single_payload_empty_payload_load(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK: entry:
 // CHECK:   %1 = load i8, ptr %0
 // CHECK:   ret i8 %1
@@ -1319,7 +1319,7 @@ entry(%p : $*DynamicSinglePayload<()>):
   return %x : $DynamicSinglePayload<()>
 }
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @dynamic_single_payload_empty_payload_store(ptr nocapture dereferenceable({{.*}}) %0, i8 %1) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @dynamic_single_payload_empty_payload_store(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, i8 %1) {{.*}} {
 // CHECK: entry:
 // CHECK:   store i8 %1, ptr %0
 // CHECK:   ret void
@@ -1444,11 +1444,11 @@ end:
   return %v : $()
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bits_switch_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bits_switch_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 sil @multi_payload_no_spare_bits_switch_indirect : $(@inout MultiPayloadNoSpareBits) -> () {
 entry(%u : $*MultiPayloadNoSpareBits):
 // CHECK-64:   [[PAYLOAD:%.*]] = load i64, ptr %0
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T11enum_future23MultiPayloadNoSpareBitsO, ptr %0, i32 0, i32 1
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T11enum_future23MultiPayloadNoSpareBitsO, ptr %0, i32 0, i32 1
 // CHECK-64:   [[TAG:%.*]] = load i8, ptr [[T0]]
 // CHECK-64:   switch i8 [[TAG]]
 // CHECK-64:   switch i64 [[PAYLOAD]]
@@ -1498,10 +1498,10 @@ entry(%0 : $Builtin.Int64):
   return %u : $MultiPayloadNoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bit_inject_x_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bit_inject_x_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   store i64 %0, ptr %1
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T11enum_future23MultiPayloadNoSpareBitsO, ptr %1, i32 0, i32 1
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T11enum_future23MultiPayloadNoSpareBitsO, ptr %1, i32 0, i32 1
 // CHECK-64:   store i8 0, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
@@ -1551,10 +1551,10 @@ entry:
   return %u : $MultiPayloadNoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bit_inject_a_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_no_spare_bit_inject_a_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   store i64 0, ptr %0
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T11enum_future23MultiPayloadNoSpareBitsO, ptr %0, i32 0, i32 1
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T11enum_future23MultiPayloadNoSpareBitsO, ptr %0, i32 0, i32 1
 // CHECK-64:   store i8 3, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
@@ -1597,12 +1597,10 @@ enum MultiPayloadOneSpareBit {
 // CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_switch(i64 %0, i8 %1) {{.*}} {
 sil @multi_payload_one_spare_bit_switch : $(MultiPayloadOneSpareBit) -> () {
 entry(%u : $MultiPayloadOneSpareBit):
-// CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i8 %1 to i1
 // CHECK-64:   [[SPARE_TAG_LSHR:%.*]] = lshr i64 %0, 63
 // CHECK-64:   [[SPARE_TAG_TRUNC:%.*]] = trunc i64 [[SPARE_TAG_LSHR]] to i8
 // CHECK-64:   [[SPARE_TAG:%.*]] = and i8 [[SPARE_TAG_TRUNC]], 1
-// CHECK-64:   [[EXTRA_TAG_ZEXT:%.*]] = zext i1 [[NATIVECC_TRUNC]] to i8
-// CHECK-64:   [[EXTRA_TAG:%.*]] = shl i8 [[EXTRA_TAG_ZEXT]], 1
+// CHECK-64:   [[EXTRA_TAG:%.*]] = shl i8 %1, 1
 // CHECK-64:   [[TAG:%.*]] = or i8 [[SPARE_TAG]], [[EXTRA_TAG]]
 // CHECK-64:   switch i8 [[TAG]], label %[[UNREACHABLE:[0-9]+]] [
 // CHECK-64:     i8 0, label %[[X_PREDEST:[0-9]+]]
@@ -1684,8 +1682,8 @@ end:
 sil @multi_payload_one_spare_bit_switch_indirect : $(@inout MultiPayloadOneSpareBit) -> () {
 entry(%u : $*MultiPayloadOneSpareBit):
 // CHECK-64:   [[PAYLOAD:%.*]] = load i64, ptr %0
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T11enum_future23MultiPayloadOneSpareBitO, ptr %0, i32 0, i32 1
-// CHECK-64:   [[TAG:%.*]] = load i1, ptr [[T0]]
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T11enum_future23MultiPayloadOneSpareBitO, ptr %0, i32 0, i32 1
+// CHECK-64:   [[TAG:%.*]] = load i8, ptr [[T0]]
 // CHECK-64:   switch i8 {{%.*}}
 // CHECK-64:   switch i64 [[PAYLOAD]]
 // CHECK-64: {{[0-9]+}}:
@@ -1742,7 +1740,7 @@ entry(%0 : $Builtin.Int62):
   return %u : $MultiPayloadOneSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_x_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_x_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i64 %0 to i62
 // CHECK-64:   [[VAL:%.*]] = zext i62 [[NATIVECC_TRUNC]] to i64
@@ -1751,8 +1749,8 @@ entry(%0 : $Builtin.Int62):
 // --                                                   0x7FFF_FFFF_FFFF_FFFF
 // CHECK-64:   [[PAYLOAD_MASKED:%.*]] = and i64 [[PAYLOAD]], 9223372036854775807
 // CHECK-64:   store i64 [[PAYLOAD_MASKED]], ptr %1
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T11enum_future23MultiPayloadOneSpareBitO, ptr %1, i32 0, i32 1
-// CHECK-64:   store i1 false, ptr [[T0]]
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T11enum_future23MultiPayloadOneSpareBitO, ptr %1, i32 0, i32 1
+// CHECK-64:   store i8 0, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
 sil @multi_payload_one_spare_bit_inject_x_indirect : $(Builtin.Int62, @inout MultiPayloadOneSpareBit) -> () {
@@ -1780,7 +1778,7 @@ entry(%0 : $Builtin.Int63):
   return %u : $MultiPayloadOneSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_y_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_y_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i64 %0 to i63
 // CHECK-64:   [[VAL:%.*]] = zext i63 [[NATIVECC_TRUNC]] to i64
@@ -1791,8 +1789,8 @@ entry(%0 : $Builtin.Int63):
 // --                                                          0x8000_0000_0000_0000
 // CHECK-64:   [[PAYLOAD_TAGGED:%.*]] = or i64 [[PAYLOAD_MASKED]], -9223372036854775808
 // CHECK-64:   store i64 [[PAYLOAD_TAGGED]], ptr %1
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T11enum_future23MultiPayloadOneSpareBitO, ptr %1, i32 0, i32 1
-// CHECK-64:   store i1 false, ptr [[T0]]
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T11enum_future23MultiPayloadOneSpareBitO, ptr %1, i32 0, i32 1
+// CHECK-64:   store i8 0, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
 
@@ -1830,12 +1828,12 @@ entry:
   return %u : $MultiPayloadOneSpareBit
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_a_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_one_spare_bit_inject_a_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // --                0x8000_0000_0000_0000
 // CHECK-64:   store i64 -9223372036854775808, ptr %0
-// CHECK-64:   [[T0:%.*]] = getelementptr inbounds %T11enum_future23MultiPayloadOneSpareBitO, ptr %0, i32 0, i32 1
-// CHECK-64:   store i1 true, ptr [[T0]]
+// CHECK-64:   [[T0:%.*]] = getelementptr inbounds{{.*}} %T11enum_future23MultiPayloadOneSpareBitO, ptr %0, i32 0, i32 1
+// CHECK-64:   store i8 1, ptr [[T0]]
 // CHECK-64:   ret void
 // CHECK-64: }
 sil @multi_payload_one_spare_bit_inject_a_indirect : $(@inout MultiPayloadOneSpareBit) -> () {
@@ -1974,7 +1972,7 @@ entry(%0 : $Builtin.Int62):
   return %u : $MultiPayloadTwoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_x_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_x_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i64 %0 to i62
 // CHECK-64:   [[VAL:%.*]] = zext i62 [[NATIVECC_TRUNC]] to i64
@@ -2008,7 +2006,7 @@ entry(%0 : $Builtin.Int60):
   return %u : $MultiPayloadTwoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_y_indirect(i64 %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_y_indirect(i64 %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   [[NATIVECC_TRUNC:%.*]] = trunc i64 %0 to i60
 // CHECK-64:   [[VAL:%.*]] = zext i60 [[NATIVECC_TRUNC]] to i64
@@ -2055,7 +2053,7 @@ entry:
   return %u : $MultiPayloadTwoSpareBits
 }
 
-// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_a_indirect(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_two_spare_bits_inject_a_indirect(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // --                0xC000_0000_0000_0000
 // CHECK-64:   store i64 -4611686018427387904, ptr %0
@@ -2231,8 +2229,9 @@ enum MultiPayloadNested {
 // CHECK:   %3 = getelementptr
 // CHECK:   %4 = load i8, ptr %3
 // CHECK:   %5 = lshr i8 %4, 7
-// CHECK:   %6 = trunc i8 %5 to i1
-// CHECK:   br i1 %6
+// CHECK:   %6 = and i8 %5, 1
+// CHECK:   %7 = icmp ne i8 %6, 1
+// CHECK:   br i1 %7
 sil @multi_payload_nested_switch : $(@in MultiPayloadNested) -> () {
 entry(%c : $*MultiPayloadNested):
   switch_enum_addr %c : $*MultiPayloadNested, case #MultiPayloadNested.A!enumelt: a_dest, case #MultiPayloadNested.B!enumelt: b_dest
@@ -2259,12 +2258,14 @@ enum MultiPayloadNestedSpareBits {
   case B(MultiPayloadInnerSpareBits)
 }
 
-// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_nested_spare_bits_switch(ptr noalias nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_nested_spare_bits_switch(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-64: entry:
 // CHECK-64:   %1 = load [[WORD]], ptr %0
 // CHECK-64:   %2 = lshr [[WORD]] %1, 61
-// CHECK-64:   %3 = trunc [[WORD]] %2 to i1
-// CHECK-64:   br i1 %3
+// CHECK-64:   %3 = trunc [[WORD]] %2 to i8
+// CHECK-64:   %4 = and i8 %3, 1
+// CHECK-64:   %5 = icmp ne i8 %4, 1
+// CHECK-64:   br i1 %5
 sil @multi_payload_nested_spare_bits_switch : $(@in MultiPayloadNestedSpareBits) -> () {
 entry(%c : $*MultiPayloadNestedSpareBits):
   switch_enum_addr %c : $*MultiPayloadNestedSpareBits, case #MultiPayloadNestedSpareBits.A!enumelt: a_dest, case #MultiPayloadNestedSpareBits.B!enumelt: b_dest
@@ -2329,7 +2330,7 @@ enum MultiPayloadAddressOnlyFixed {
   case Y(Builtin.Int32)
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_address_only_destroy(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @multi_payload_address_only_destroy(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 sil @multi_payload_address_only_destroy : $@convention(thin) (@in MultiPayloadAddressOnlyFixed) -> () {
 entry(%m : $*MultiPayloadAddressOnlyFixed):
   destroy_addr %m : $*MultiPayloadAddressOnlyFixed
@@ -2463,7 +2464,7 @@ entry(%x : $Int32):
   // CHECK-64: [[INT_ZEXT:%.*]] = zext i32 %0 to i64
   // CHECK-64: [[INT_SHL:%.*]] = shl i64 [[INT_ZEXT]], 32
   %d = enum $Optional<(Optional<()>, Int32)>, #Optional.some!enumelt, %c : $(Optional<()>, Int32)
-  // CHECK-64: [[BIT:%.*]] = trunc i64 [[INT_SHL]] to i1
+  // CHECK-64: [[BIT:%.*]] = trunc i64 [[INT_SHL]] to i8
   // CHECK-64: [[INT_SHR:%.*]] = lshr i64 [[INT_SHL]], 32
   // CHECK-64: [[INT:%.*]] = trunc i64 [[INT_SHR]] to i32
   %e = unchecked_enum_data %d : $Optional<(Optional<()>, Int32)>, #Optional.some!enumelt
@@ -2615,11 +2616,11 @@ entry(%x : $*MyOptional):
 // CHECK:   [[T_VWT:%.*]] = load ptr, ptr [[T_VWT_ADDR]]
 // CHECK:   [[T_LAYOUT:%.*]] = getelementptr inbounds ptr, ptr [[T_VWT]], i32 8
 // CHECK:   call void @swift_initEnumMetadataSingleCase(ptr [[METADATA]], [[WORD]] 0, ptr [[T_LAYOUT]])
-// CHECK:   [[PAYLOAD_EXTRAINHABITANTCNT:%.*]] = getelementptr inbounds %swift.type_layout, ptr [[T_LAYOUT]], i32 0, i32 3
+// CHECK:   [[PAYLOAD_EXTRAINHABITANTCNT:%.*]] = getelementptr inbounds{{.*}} %swift.type_layout, ptr [[T_LAYOUT]], i32 0, i32 3
 // CHECK:   [[CNT:%.*]] = load i32, ptr [[PAYLOAD_EXTRAINHABITANTCNT]]
 // CHECK:   [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[METADATA]], [[WORD]] -1
 // CHECK:   [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
-// CHECK:   [[XIC_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 11
+// CHECK:   [[XIC_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 11
 // CHECK:   store i32 [[CNT]], ptr [[XIC_ADDR]]
 // CHECK:   ret %swift.metadata_response
 
diff --git a/test/IRGen/enum_resilience.swift b/test/IRGen/enum_resilience.swift
index 3220e4a0c1ef9..7f8f7d023afa0 100644
--- a/test/IRGen/enum_resilience.swift
+++ b/test/IRGen/enum_resilience.swift
@@ -184,7 +184,7 @@ public func constructResilientEnumPayload(_ s: Size) -> Medium {
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
 
-// CHECK: [[WITNESS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+// CHECK: [[WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
 // CHECK: [[WITNESS_FOR_SIZE:%size]] = load [[INT]], ptr [[WITNESS_ADDR]]
 // CHECK: [[ALLOCA:%.*]] = alloca i8, {{.*}} [[WITNESS_FOR_SIZE]], align 16
 // CHECK: [[ALLOCA:%.*]] = alloca i8, {{.*}} [[WITNESS_FOR_SIZE]], align 16
@@ -260,7 +260,7 @@ public func resilientEnumPartialApply(_ f: (Medium) -> Int) {
 
 }
 
-// CHECK-LABEL: define internal swiftcc void @"$s14resilient_enum6MediumOSiIgnd_ACSiIegnr_TRTA"(ptr noalias nocapture sret({{.*}}) %0, ptr noalias %1, ptr swiftself %2)
+// CHECK-LABEL: define internal swiftcc void @"$s14resilient_enum6MediumOSiIgnd_ACSiIegnr_TRTA"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias %1, ptr swiftself %2)
 
 
 // Enums with resilient payloads from a different resilience domain
diff --git a/test/IRGen/enum_value_semantics.sil b/test/IRGen/enum_value_semantics.sil
index 23091ebfb4896..a5a973ab7916f 100644
--- a/test/IRGen/enum_value_semantics.sil
+++ b/test/IRGen/enum_value_semantics.sil
@@ -195,7 +195,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 // -- NoPayload getEnumTag
 // CHECK-LABEL: define internal i32 @"$s20enum_value_semantics9NoPayloadOwug"
-// CHECK: [[TAG_ADDR:%.*]] = getelementptr inbounds %T20enum_value_semantics9NoPayloadO, ptr %value, i32 0, i32 0
+// CHECK: [[TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics9NoPayloadO, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[TAG:%.*]] = load i8, ptr [[TAG_ADDR]], align 1
 // CHECK-NEXT: [[RESULT:%.*]] = zext i8 [[TAG]] to i32
 // CHECK-NEXT: ret i32 [[RESULT]]
@@ -209,7 +209,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // -- NoPayload destructiveInjectEnumTag
 // CHECK-LABEL: define internal void @"$s20enum_value_semantics9NoPayloadOwui"
 // CHECK: [[TAG:%.*]] = trunc i32 %tag to i8
-// CHECK-NEXT: [[TAG_ADDR:%.*]] = getelementptr inbounds %T20enum_value_semantics9NoPayloadO, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics9NoPayloadO, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i8 [[TAG]], ptr [[TAG_ADDR]], align 1
 // CHECK-NEXT: ret void
 
@@ -295,7 +295,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK: [[NO_PAYLOAD_TAG_TMP:%.*]] = load i64, ptr %value, align 8
 
 //   -- Load the high bits of the tag from the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T20enum_value_semantics19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
 // CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i8, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i8 [[EXTRA_TAG_TMP]] to i32
 
@@ -329,7 +329,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: store i64 [[NO_PAYLOAD_TAG2]], ptr %value, align 8
 
 //   -- Store the high bits of the tag in the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T20enum_value_semantics19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
 // CHECK-NEXT: store i8 2, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: br label %[[DONE:.*]]
 
@@ -337,7 +337,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 //   -- Store the tag in the extra tag area
 // CHECK-NEXT: [[TAG:%.*]] = trunc i32 %tag to i8
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T20enum_value_semantics19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
 // CHECK-NEXT: store i8 [[TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: br label %[[DONE]]
 
@@ -356,9 +356,9 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 //   -- The payload has no spare bits and there are no empty cases, so the tag
 //      is entirely contained in the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T20enum_value_semantics24MultiPayloadNoEmptyCasesO, ptr %value, i32 0, i32 1
-// CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i1, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
-// CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i1 [[EXTRA_TAG_TMP]] to i32
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics24MultiPayloadNoEmptyCasesO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i8, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
+// CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i8 [[EXTRA_TAG_TMP]] to i32
 // CHECK-NEXT: ret i32 [[EXTRA_TAG]]
 
 // -- MultiPayloadNoEmptyCases destructiveProjectEnumData
@@ -368,11 +368,11 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 // -- MultiPayloadNoEmptyCases destructiveInjectEnumTag
 // CHECK-LABEL: define internal void @"$s20enum_value_semantics24MultiPayloadNoEmptyCasesOwui"
-// CHECK: [[TAG:%.*]] = trunc i32 %tag to i1
+// CHECK: [[TAG:%.*]] = trunc i32 %tag to i8
 
 //   -- Store the tag in the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T20enum_value_semantics24MultiPayloadNoEmptyCasesO, ptr %value, i32 0, i32 1
-// CHECK-NEXT: store i1 [[TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics24MultiPayloadNoEmptyCasesO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: store i8 [[TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: ret void
 
 
@@ -385,7 +385,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-LABEL: define internal i32 @"$s20enum_value_semantics017MultiPayloadEmptyE0Owug"
 
 //   -- Load the tag from the extra tag area
-// CHECK: [[EXTRA_TAG_ADDR:%.*]] = getelementptr inbounds %T20enum_value_semantics017MultiPayloadEmptyE0O, ptr %value, i32 0, i32 0
+// CHECK: [[EXTRA_TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics017MultiPayloadEmptyE0O, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i8, ptr [[EXTRA_TAG_ADDR]], align 1
 // CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i8 [[EXTRA_TAG_TMP]] to i32
 // CHECK-NEXT: ret i32 [[EXTRA_TAG]]
@@ -401,7 +401,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 //   -- Store the tag in the extra tag area
 // CHECK: [[TAG:%.*]] = trunc i32 %tag to i8
-// CHECK-NEXT: [[EXTRA_TAG_ADDR:%.*]] = getelementptr inbounds %T20enum_value_semantics017MultiPayloadEmptyE0O, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[EXTRA_TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics017MultiPayloadEmptyE0O, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i8 [[TAG]], ptr [[EXTRA_TAG_ADDR]], align 1
 // CHECK-NEXT: ret void
 
@@ -417,7 +417,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: [[PAYLOAD_0:%.*]] = load i64, ptr [[PAYLOAD_0_ADDR]], align 8
 // CHECK-NEXT: [[PAYLOAD_1_ADDR:%.*]] = getelementptr
 // CHECK-NEXT: [[PAYLOAD_1:%.*]] = load i64, ptr [[PAYLOAD_1_ADDR]], align 8
-// CHECK: [[T0:%.*]] = getelementptr inbounds %T20enum_value_semantics22MultiPayloadNontrivialO, ptr [[OBJ]], i32 0, i32 1
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics22MultiPayloadNontrivialO, ptr [[OBJ]], i32 0, i32 1
 // CHECK-NEXT: [[TAG:%.*]] = load i8, ptr [[T0]], align 8
 // CHECK-NEXT: @"$s20enum_value_semantics22MultiPayloadNontrivialOWOe"
 // CHECK-NEXT: ret void
@@ -461,9 +461,9 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-LABEL: define internal i32 @"$s20enum_value_semantics31MultiPayloadNontrivialSpareBitsOwug"
 
 //   -- Load the payload
-// CHECK: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[FIRST:%.*]] = load i64, ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: [[SECOND:%.*]] = load i64, ptr [[SECOND_ADDR]], align 8
 
 //   -- Get the high bits of the tag from the spare bits
@@ -486,18 +486,18 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-LABEL: define internal void @"$s20enum_value_semantics31MultiPayloadNontrivialSpareBitsOwup"
 
 //   -- Load the payload
-// CHECK: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[FIRST:%.*]] = load i64, ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: [[SECOND:%.*]] = load i64, ptr [[SECOND_ADDR]], align 8
 
 //   -- Strip off spare bits
 // CHECK-NEXT: [[SECOND_PROJ:%.*]] = and i64 [[SECOND]], 4611686018427387903
 
 //   -- Store the payload
-// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i64 [[FIRST]], ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: store i64 [[SECOND_PROJ]], ptr [[SECOND_ADDR]], align 8
 // CHECK-NEXT: ret void
 
@@ -513,11 +513,11 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: [[NO_PAYLOAD_TAG2:%.*]] = zext i32 [[NO_PAYLOAD_TAG]] to i64
 
 //   -- Store the low bits of the tag into the payload
-// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i64 [[NO_PAYLOAD_TAG2]], ptr [[FIRST_ADDR]], align 8
 
 //   -- Store the high bits of the tag into the spare bits
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 //   -- 0xc000000000000000
 // CHECK-NEXT: store i64 -4611686018427387904, ptr [[SECOND_ADDR]], align 8
 // CHECK-NEXT: br label %[[END:.*]]
@@ -528,9 +528,9 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: [[TAG_TMP:%.*]] = and i32 %tag, 3
 
 //   -- Load the payload
-// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[FIRST:%.*]] = load i64, ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: [[SECOND:%.*]] = load i64, ptr [[SECOND_ADDR]], align 8
 
 //   -- Mask off spare bits in the payload               -- 0x00fffffffffffff8
@@ -547,9 +547,9 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: [[SECOND_NEW:%.*]] = or i64 [[SPARE_TAG_TMP]], [[SECOND_PROJ]]
 
 //   -- Store the payload back
-// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i64 [[FIRST]], ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: store i64 [[SECOND_NEW]], ptr [[SECOND_ADDR]], align 8
 // CHECK-NEXT: br label %[[END]]
 
@@ -563,14 +563,13 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK: [[PAYLOAD:%.*]] = load i64, ptr %value, align 8
 
 //   -- Load the load bits of the tag from the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T20enum_value_semantics029MultiPayloadSpareBitsAndExtraG0O, ptr %value, i32 0, i32 1
-// CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i1, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics029MultiPayloadSpareBitsAndExtraG0O, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG:%.*]] = load i8, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 
 //   -- Load the high bits of the tag from the spare bits area
 // CHECK-NEXT: [[SPARE_BITS_TMP2:%.*]] = lshr i64 [[PAYLOAD]], 63
 // CHECK-NEXT: [[SPARE_BITS_TMP:%.*]] = trunc i64 [[SPARE_BITS_TMP2]] to i8
 // CHECK-NEXT: [[SPARE_BITS:%.*]] = and i8 [[SPARE_BITS_TMP]], 1
-// CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i1 [[EXTRA_TAG_TMP]] to i8
 
 //   -- Combine high bits and low bits to form tag
 // CHECK-NEXT: [[TAG_TMP:%.*]] = shl i8 [[EXTRA_TAG]], 1
@@ -609,7 +608,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 //   -- Store high bits of tag in extra tag area
 // CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = lshr i32 %tag, 1
-// CHECK-NEXT: [[EXTRA_TAG:%.*]] = trunc i32 [[EXTRA_TAG_TMP]] to i1
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T20enum_value_semantics029MultiPayloadSpareBitsAndExtraG0O, ptr %value, i32 0, i32 1
-// CHECK-NEXT: store i1 [[EXTRA_TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
+// CHECK-NEXT: [[EXTRA_TAG:%.*]] = trunc i32 [[EXTRA_TAG_TMP]] to i8
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T20enum_value_semantics029MultiPayloadSpareBitsAndExtraG0O, ptr %value, i32 0, i32 1
+// CHECK-NEXT: store i8 [[EXTRA_TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: ret void
diff --git a/test/IRGen/enum_value_semantics_future.sil b/test/IRGen/enum_value_semantics_future.sil
index d950e725a816a..f9dd4c6c6d4a8 100644
--- a/test/IRGen/enum_value_semantics_future.sil
+++ b/test/IRGen/enum_value_semantics_future.sil
@@ -204,7 +204,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 // -- NoPayload getEnumTag
 // CHECK-LABEL: define internal i32 @"$s27enum_value_semantics_future9NoPayloadOwug"
-// CHECK: [[TAG_ADDR:%.*]] = getelementptr inbounds %T27enum_value_semantics_future9NoPayloadO, ptr %value, i32 0, i32 0
+// CHECK: [[TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future9NoPayloadO, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[TAG:%.*]] = load i8, ptr [[TAG_ADDR]], align 1
 // CHECK-NEXT: [[RESULT:%.*]] = zext i8 {{.*}} to i32
 // CHECK-NEXT: ret i32 [[RESULT]]
@@ -218,7 +218,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // -- NoPayload destructiveInjectEnumTag
 // CHECK-LABEL: define internal void @"$s27enum_value_semantics_future9NoPayloadOwui"
 // CHECK: [[TAG:%.*]] = trunc i32 %tag to i8
-// CHECK-NEXT: [[TAG_ADDR:%.*]] = getelementptr inbounds %T27enum_value_semantics_future9NoPayloadO, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future9NoPayloadO, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i8 [[TAG]], ptr [[TAG_ADDR]], align 1
 // CHECK-NEXT: ret void
 
@@ -300,7 +300,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK: [[NO_PAYLOAD_TAG_TMP:%.*]] = load i64, ptr %value, align 8
 
 //   -- Load the high bits of the tag from the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T27enum_value_semantics_future19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
 // CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i8, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i8 [[EXTRA_TAG_TMP]] to i32
 
@@ -334,7 +334,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: store i64 [[NO_PAYLOAD_TAG2]], ptr %value, align 8
 
 //   -- Store the high bits of the tag in the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T27enum_value_semantics_future19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
 // CHECK-NEXT: store i8 2, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: br label %[[DONE:.*]]
 
@@ -342,7 +342,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 //   -- Store the tag in the extra tag area
 // CHECK-NEXT: [[TAG:%.*]] = trunc i32 %tag to i8
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T27enum_value_semantics_future19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future19MultiPayloadTrivialO, ptr %value, i32 0, i32 1
 // CHECK-NEXT: store i8 [[TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: br label %[[DONE]]
 
@@ -361,9 +361,9 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 //   -- The payload has no spare bits and there are no empty cases, so the tag
 //      is entirely contained in the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T27enum_value_semantics_future24MultiPayloadNoEmptyCasesO, ptr %value, i32 0, i32 1
-// CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i1, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
-// CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i1 [[EXTRA_TAG_TMP]] to i32
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future24MultiPayloadNoEmptyCasesO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i8, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
+// CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i8 [[EXTRA_TAG_TMP]] to i32
 // CHECK-NEXT: ret i32 [[EXTRA_TAG]]
 
 // -- MultiPayloadNoEmptyCases destructiveProjectEnumData
@@ -373,11 +373,11 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 // -- MultiPayloadNoEmptyCases destructiveInjectEnumTag
 // CHECK-LABEL: define internal void @"$s27enum_value_semantics_future24MultiPayloadNoEmptyCasesOwui"
-// CHECK: [[TAG:%.*]] = trunc i32 %tag to i1
+// CHECK: [[TAG:%.*]] = trunc i32 %tag to i8
 
 //   -- Store the tag in the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T27enum_value_semantics_future24MultiPayloadNoEmptyCasesO, ptr %value, i32 0, i32 1
-// CHECK-NEXT: store i1 [[TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future24MultiPayloadNoEmptyCasesO, ptr %value, i32 0, i32 1
+// CHECK-NEXT: store i8 [[TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: ret void
 
 
@@ -390,7 +390,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-LABEL: define internal i32 @"$s27enum_value_semantics_future017MultiPayloadEmptyF0Owug"
 
 //   -- Load the tag from the extra tag area
-// CHECK: [[EXTRA_TAG_ADDR:%.*]] = getelementptr inbounds %T27enum_value_semantics_future017MultiPayloadEmptyF0O, ptr %value, i32 0, i32 0
+// CHECK: [[EXTRA_TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future017MultiPayloadEmptyF0O, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i8, ptr [[EXTRA_TAG_ADDR]], align 1
 // CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i8 [[EXTRA_TAG_TMP]] to i32
 // CHECK-NEXT: ret i32 [[EXTRA_TAG]]
@@ -406,7 +406,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 //   -- Store the tag in the extra tag area
 // CHECK: [[TAG:%.*]] = trunc i32 %tag to i8
-// CHECK-NEXT: [[EXTRA_TAG_ADDR:%.*]] = getelementptr inbounds %T27enum_value_semantics_future017MultiPayloadEmptyF0O, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[EXTRA_TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future017MultiPayloadEmptyF0O, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i8 [[TAG]], ptr [[EXTRA_TAG_ADDR]], align 1
 // CHECK-NEXT: ret void
 
@@ -422,7 +422,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: [[PAYLOAD_0:%.*]] = load i64, ptr [[PAYLOAD_0_ADDR]], align 8
 // CHECK-NEXT: [[PAYLOAD_1_ADDR:%.*]] = getelementptr
 // CHECK-NEXT: [[PAYLOAD_1:%.*]] = load i64, ptr [[PAYLOAD_1_ADDR]], align 8
-// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds %T27enum_value_semantics_future22MultiPayloadNontrivialO, ptr {{.*}}, i32 0, i32 1
+// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future22MultiPayloadNontrivialO, ptr {{.*}}, i32 0, i32 1
 // CHECK-NEXT: [[TAG:%.*]] = load i8, ptr [[T0]], align 8
 // CHECK-NEXT: @"$s27enum_value_semantics_future22MultiPayloadNontrivialOWOe"
 // CHECK-NEXT: ret void
@@ -466,9 +466,9 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-LABEL: define internal i32 @"$s27enum_value_semantics_future31MultiPayloadNontrivialSpareBitsOwug"
 
 //   -- Load the payload
-// CHECK: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[FIRST:%.*]] = load i64, ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: [[SECOND:%.*]] = load i64, ptr [[SECOND_ADDR]], align 8
 
 //   -- Get the high bits of the tag from the spare bits
@@ -491,18 +491,18 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-LABEL: define internal void @"$s27enum_value_semantics_future31MultiPayloadNontrivialSpareBitsOwup"
 
 //   -- Load the payload
-// CHECK: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[FIRST:%.*]] = load i64, ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: [[SECOND:%.*]] = load i64, ptr [[SECOND_ADDR]], align 8
 
 //   -- Strip off spare bits
 // CHECK-NEXT: [[SECOND_PROJ:%.*]] = and i64 [[SECOND]], 4611686018427387903
 
 //   -- Store the payload
-// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i64 [[FIRST]], ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: store i64 [[SECOND_PROJ]], ptr [[SECOND_ADDR]], align 8
 // CHECK-NEXT: ret void
 
@@ -518,11 +518,11 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: [[NO_PAYLOAD_TAG2:%.*]] = zext i32 [[NO_PAYLOAD_TAG]] to i64
 
 //   -- Store the low bits of the tag into the payload
-// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i64 [[NO_PAYLOAD_TAG2]], ptr [[FIRST_ADDR]], align 8
 
 //   -- Store the high bits of the tag into the spare bits
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 //   -- 0xc000000000000000
 // CHECK-NEXT: store i64 -4611686018427387904, ptr [[SECOND_ADDR]], align 8
 // CHECK-NEXT: br label %[[END:.*]]
@@ -533,9 +533,9 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: [[TAG_TMP:%.*]] = and i32 %tag, 3
 
 //   -- Load the payload
-// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: [[FIRST:%.*]] = load i64, ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: [[SECOND:%.*]] = load i64, ptr [[SECOND_ADDR]], align 8
 
 //   -- Mask off spare bits in the payload               -- 0x00fffffffffffff8
@@ -552,9 +552,9 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK-NEXT: [[SECOND_NEW:%.*]] = or i64 [[SPARE_TAG_TMP]], [[SECOND_PROJ]]
 
 //   -- Store the payload back
-// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 0
+// CHECK-NEXT: [[FIRST_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 0
 // CHECK-NEXT: store i64 [[FIRST]], ptr [[FIRST_ADDR]], align 8
-// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds { i64, i64 }, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[SECOND_ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64 }, ptr %value, i32 0, i32 1
 // CHECK-NEXT: store i64 [[SECOND_NEW]], ptr [[SECOND_ADDR]], align 8
 // CHECK-NEXT: br label %[[END]]
 
@@ -568,14 +568,13 @@ bb0(%0 : $SinglePayloadNontrivial):
 // CHECK: [[PAYLOAD:%.*]] = load i64, ptr %value, align 8
 
 //   -- Load the load bits of the tag from the extra tag area
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T27enum_value_semantics_future029MultiPayloadSpareBitsAndExtraH0O, ptr %value, i32 0, i32 1
-// CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = load i1, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future029MultiPayloadSpareBitsAndExtraH0O, ptr %value, i32 0, i32 1
+// CHECK-NEXT: [[EXTRA_TAG:%.*]] = load i8, ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 
 //   -- Load the high bits of the tag from the spare bits area
 // CHECK-NEXT: [[SPARE_BITS_TMP2:%.*]] = lshr i64 [[PAYLOAD]], 63
 // CHECK-NEXT: [[SPARE_BITS_TMP:%.*]] = trunc i64 [[SPARE_BITS_TMP2]] to i8
 // CHECK-NEXT: [[SPARE_BITS:%.*]] = and i8 [[SPARE_BITS_TMP]], 1
-// CHECK-NEXT: [[EXTRA_TAG:%.*]] = zext i1 [[EXTRA_TAG_TMP]] to i8
 
 //   -- Combine high bits and low bits to form tag
 // CHECK-NEXT: [[TAG_TMP:%.*]] = shl i8 [[EXTRA_TAG]], 1
@@ -614,7 +613,7 @@ bb0(%0 : $SinglePayloadNontrivial):
 
 //   -- Store high bits of tag in extra tag area
 // CHECK-NEXT: [[EXTRA_TAG_TMP:%.*]] = lshr i32 %tag, 1
-// CHECK-NEXT: [[EXTRA_TAG:%.*]] = trunc i32 [[EXTRA_TAG_TMP]] to i1
-// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds %T27enum_value_semantics_future029MultiPayloadSpareBitsAndExtraH0O, ptr %value, i32 0, i32 1
-// CHECK-NEXT: store i1 [[EXTRA_TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
+// CHECK-NEXT: [[EXTRA_TAG:%.*]] = trunc i32 [[EXTRA_TAG_TMP]] to i8
+// CHECK-NEXT: [[EXTRA_TAG_ADDR_TMP:%.*]] = getelementptr inbounds{{.*}} %T27enum_value_semantics_future029MultiPayloadSpareBitsAndExtraH0O, ptr %value, i32 0, i32 1
+// CHECK-NEXT: store i8 [[EXTRA_TAG]], ptr [[EXTRA_TAG_ADDR_TMP]], align 8
 // CHECK-NEXT: ret void
diff --git a/test/IRGen/errors.sil b/test/IRGen/errors.sil
index fbb5d067594a3..2f2c7ee65462c 100644
--- a/test/IRGen/errors.sil
+++ b/test/IRGen/errors.sil
@@ -15,17 +15,16 @@ entry:
   unreachable
 }
 
-// CHECK-LABEL-i386:   define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr %1) {{.*}} {
-// CHECK-LABEL-x86_64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-armv7:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-armv7s: define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-armv7k: define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-arm64:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-arm64e:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-aarch64:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-arm64_32:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-arm64e:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-wasm32:  define swiftcc void @does_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
+// CHECK-i386-LABEL:   define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr %1) {{.*}} {
+// CHECK-x86_64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-armv7-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-armv7s-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-armv7k-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-arm64-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-arm64e-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-aarch64-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-arm64_32-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @does_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-wasm32-LABEL:  define swiftcc void @does_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
 sil @does_throw : $@convention(thin) () -> @error Error {
   // CHECK: [[T0:%.*]] = call swiftcc ptr @create_error()
   %0 = function_ref @create_error : $@convention(thin) () -> @owned Error
@@ -40,17 +39,16 @@ sil @does_throw : $@convention(thin) () -> @error Error {
   throw %1 : $Error
 }
 
-// CHECK-LABEL-i386:   define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr %1) {{.*}} {
-// CHECK-LABEL-x86_64: define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-armv7:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-armv7s: define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-armv7k: define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-arm64:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-arm64e:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-aarch64:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-arm64e:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-arm64_32:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
-// CHECK-LABEL-wasm32: define swiftcc void @doesnt_throw(ptr swiftself %0, ptr swifterror %1) {{.*}} {
+// CHECK-i386-LABEL:   define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr %1) {{.*}} {
+// CHECK-x86_64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-armv7-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-armv7s-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-armv7k-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-arm64-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-arm64e-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-aarch64-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-arm64_32-LABEL:  define{{( dllexport)?}}{{( protected)?}} swiftcc void @doesnt_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
+// CHECK-wasm32-LABEL: define swiftcc void @doesnt_throw(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.}}) %1) {{.*}} {
 sil @doesnt_throw : $@convention(thin) () -> @error Error {
   //   We don't have to do anything here because the caller always
   //   zeroes the error slot before a call.
@@ -79,8 +77,8 @@ entry(%0 : $AnyObject):
   // CHECK-wasm32:      [[ERRORSLOT:%.*]] = alloca [[SWIFTERROR:.*]] ptr, align
   // CHECK-NEXT: store ptr null, ptr [[ERRORSLOT]], align
 
-  // CHECK-objc-NEXT: [[RESULT:%.*]] = call swiftcc ptr @try_apply_helper(ptr %0, ptr swiftself undef, ptr noalias nocapture [[SWIFTERROR]]{{( )?}}dereferenceable({{.}}) [[ERRORSLOT]])
-  // CHECK-native-NEXT: [[RESULT:%.*]] = call swiftcc ptr @try_apply_helper(ptr %0, ptr swiftself undef, ptr noalias nocapture [[SWIFTERROR]]{{( )?}}dereferenceable({{.}}) [[ERRORSLOT]])
+  // CHECK-objc-NEXT: [[RESULT:%.*]] = call swiftcc ptr @try_apply_helper(ptr %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} [[SWIFTERROR]]{{( )?}}{{(captures\(none\) )?}}dereferenceable({{.}}) [[ERRORSLOT]])
+  // CHECK-native-NEXT: [[RESULT:%.*]] = call swiftcc ptr @try_apply_helper(ptr %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} [[SWIFTERROR]]{{( )?}}{{(captures\(none\) )?}}dereferenceable({{.}}) [[ERRORSLOT]])
   // CHECK-NEXT: [[ERR:%.*]] = load ptr, ptr [[ERRORSLOT]], align
   // CHECK-NEXT: [[T0:%.*]] = icmp ne ptr [[ERR]], null
   // CHECK-NEXT: ptrtoint ptr [[ERR]] to i
@@ -116,7 +114,7 @@ enum ColorError : Error {
 }
 
 // CHECK-LABEL: TestCallToWillThrowCallBack
-// CHECK: call swiftcc void @swift_willThrow(ptr swiftself undef, ptr noalias nocapture readonly [[SWIFTERROR]]{{( )?}}dereferenceable({{.}}) %2)
+// CHECK: call swiftcc void @swift_willThrow(ptr swiftself undef, ptr noalias{{( nocapture)?}} readonly [[SWIFTERROR]]{{( )?}}{{(captures\(none\) )?}}dereferenceable({{.}}) %2)
 // CHECK: store ptr %0
 // CHECK: ret i64 undef
 sil hidden @TestCallToWillThrowCallBack : $@convention(thin) (@owned Error) -> (Int64, @error Error) {
@@ -130,8 +128,8 @@ bb0(%0 : $Error):
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_single(ptr %0)
 // CHECK:       insertvalue { ptr, ptr } { ptr @"$s27partial_apply_single_helperTA{{(\.ptrauth)?}}", ptr undef },
 
-// CHECK: define internal swiftcc void @"$s27partial_apply_single_helperTA"(ptr swiftself %0, ptr noalias nocapture{{( )?}}[[SWIFTERROR]]{{( )?}}dereferenceable({{.}}) %1)
-// CHECK:  tail call swiftcc void @partial_apply_single_helper(ptr {{%.*}}, ptr swiftself undef, ptr noalias nocapture{{( )?}}[[SWIFTERROR]]{{( )?}}dereferenceable({{.}}){{( )?}}{{%.*}})
+// CHECK: define internal swiftcc void @"$s27partial_apply_single_helperTA"(ptr swiftself %0, ptr noalias{{( nocapture)?}} [[SWIFTERROR]]{{( )?}}{{(captures\(none\) )?}}dereferenceable({{.}}) %1)
+// CHECK:  tail call swiftcc void @partial_apply_single_helper(ptr {{%.*}}, ptr swiftself undef, ptr noalias{{( nocapture)?}} [[SWIFTERROR]]{{( )?}}{{(captures\(none\) )?}}dereferenceable({{.}}){{( )?}}{{%.*}})
 // CHECK-NEXT:  ret void
 sil @partial_apply_single : $@convention(thin) (@owned A) -> @callee_owned () -> @error Error {
 entry(%0 : $A):
diff --git a/test/IRGen/exclusivity.sil b/test/IRGen/exclusivity.sil
index fd3ccf3c08962..656173cf0397f 100644
--- a/test/IRGen/exclusivity.sil
+++ b/test/IRGen/exclusivity.sil
@@ -18,14 +18,14 @@ bb0(%0 : $A):
   // CHECK: [[SCRATCH0:%.*]] = alloca [[BUFFER_T:\[.* x i8\]]],
   // CHECK: [[SCRATCH1:%.*]] = alloca [[BUFFER_T:\[.* x i8\]]],
 
-  // CHECK: [[PROP:%.*]] = getelementptr inbounds [[C:%T11exclusivity1AC]], ptr %0, i32 0, i32 1
+  // CHECK: [[PROP:%.*]] = getelementptr inbounds{{.*}} [[C:%T11exclusivity1AC]], ptr %0, i32 0, i32 1
   %3 = ref_element_addr %0 : $A, #A.x
 
   // CHECK: call void @llvm.lifetime.start.p0(i64 -1, ptr [[SCRATCH0]])
   // CHECK: call void @swift_beginAccess(ptr [[PROP]], ptr [[SCRATCH0]], [[SIZE_T:i32|i64]] 32, ptr null)
   %4 = begin_access [read] [dynamic] %3 : $*Int
 
-  // CHECK: [[T0:%.*]] = getelementptr inbounds [[INT:%TSi]], ptr %1, i32 0, i32 0
+  // CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [[INT:%TSi]], ptr %1, i32 0, i32 0
   // CHECK: load {{(i64|i32)}}, ptr [[T0]]
   %5 = load %4 : $*Int
 
@@ -35,7 +35,7 @@ bb0(%0 : $A):
 
   %9 = function_ref @changeInt : $@convention(thin) (@inout Int) -> ()
 
-  // CHECK: [[PROP:%.*]] = getelementptr inbounds [[C:%T11exclusivity1AC]], ptr %0, i32 0, i32 1
+  // CHECK: [[PROP:%.*]] = getelementptr inbounds{{.*}} [[C:%T11exclusivity1AC]], ptr %0, i32 0, i32 1
   %11 = ref_element_addr %0 : $A, #A.x
 
   // CHECK: call void @llvm.lifetime.start.p0(i64 -1, ptr [[SCRATCH1]])
diff --git a/test/IRGen/existential_metatypes.sil b/test/IRGen/existential_metatypes.sil
index fc216e378e8d0..b2ba3ddb56cb2 100644
--- a/test/IRGen/existential_metatypes.sil
+++ b/test/IRGen/existential_metatypes.sil
@@ -58,17 +58,17 @@ bb0:
   // CHECK:      [[V:%.*]] = alloca { ptr, ptr }, align 8
   // CHECK-NEXT: llvm.lifetime.start
   %0 = alloc_stack $@thick Kindable.Type, var, name "v"
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds { ptr, ptr }, ptr [[V]], i32 0, i32 0
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} { ptr, ptr }, ptr [[V]], i32 0, i32 0
   // CHECK-NEXT: store ptr @"$sSiN", ptr [[T0]], align 8
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds { ptr, ptr }, ptr [[V]], i32 0, i32 1
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} { ptr, ptr }, ptr [[V]], i32 0, i32 1
   %1 = metatype $@thin Int.Type
   %2 = metatype $@thick Int.Type
   %3 = init_existential_metatype %2 : $@thick Int.Type, $@thick Kindable.Type
   // CHECK-NEXT: store ptr @"$sSi21existential_metatypes8KindableAAWP", ptr [[T0]], align 8
   store %3 to %0 : $*@thick Kindable.Type
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds { ptr, ptr }, ptr [[V]], i32 0, i32 0
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} { ptr, ptr }, ptr [[V]], i32 0, i32 0
   // CHECK-NEXT: store ptr @"$sSfN", ptr [[T0]], align 8
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds { ptr, ptr }, ptr [[V]], i32 0, i32 1
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} { ptr, ptr }, ptr [[V]], i32 0, i32 1
   %5 = metatype $@thin Float.Type
   %6 = metatype $@thick Float.Type
   %7 = init_existential_metatype %6 : $@thick Float.Type, $@thick Kindable.Type
diff --git a/test/IRGen/existential_shape_metadata.swift b/test/IRGen/existential_shape_metadata.swift
index b065f4582c781..4a4ef092da7de 100644
--- a/test/IRGen/existential_shape_metadata.swift
+++ b/test/IRGen/existential_shape_metadata.swift
@@ -46,7 +46,7 @@ public func testConcrete() -> Any.Type {
 // CHECK-LABEL: define{{.*}} @"$s26existential_shape_metadata13testDependent
 public func testDependent<T>(t: T.Type) -> Any.Type {
   // CHECK: [[ARGS:%.*]] = alloca [1 x ptr], align
-  // CHECK: [[T0:%.*]] = getelementptr inbounds [1 x ptr], ptr [[ARGS]], i32 0, i32 0
+  // CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[ARGS]], i32 0, i32 0
   // CHECK: store ptr %T, ptr [[T0]], align
   // CHECK: [[METADATA:%.*]] = call ptr @swift_getExtendedExistentialTypeMetadata(ptr @"$sl26existential_shape_metadata2Q0_px1TRts_XPXGMq{{(\.ptrauth)?}}", ptr [[ARGS]])
   // CHECK: ret ptr [[METADATA]]
@@ -59,7 +59,7 @@ public func testComplexApplication<T>(t: T.Type) -> Any.Type {
   // CHECK: [[ARGS:%.*]] = alloca [1 x ptr], align
   // CHECK: [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s26existential_shape_metadata1BVMa"([[INT]] 255, ptr %T)
   // CHECK: [[B_T:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
-  // CHECK: [[T0:%.*]] = getelementptr inbounds [1 x ptr], ptr [[ARGS]], i32 0, i32 0
+  // CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[ARGS]], i32 0, i32 0
   // CHECK: store ptr [[B_T]], ptr [[T0]], align
   // CHECK: [[METADATA:%.*]] = call ptr @swift_getExtendedExistentialTypeMetadata(ptr @"$sl26existential_shape_metadata2Q0_px1TRts_XPXGMq{{(\.ptrauth)?}}", ptr [[ARGS]])
   // CHECK: ret ptr [[METADATA]]
@@ -70,7 +70,7 @@ public func testComplexApplication<T>(t: T.Type) -> Any.Type {
 // CHECK-LABEL: define{{.*}} @"$s26existential_shape_metadata12test_private
 public func test_private<T>(t: T.Type) -> Any.Type {
   // CHECK: [[ARGS:%.*]] = alloca [1 x ptr], align
-  // CHECK: [[T0:%.*]] = getelementptr inbounds [1 x ptr], ptr [[ARGS]], i32 0, i32 0
+  // CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[ARGS]], i32 0, i32 0
   // CHECK: store ptr %T, ptr [[T0]], align
   //   FIXME: this should be unique?
   // CHECK: [[METADATA:%.*]] = call ptr @swift_getExtendedExistentialTypeMetadata_unique(ptr @"$sl26existential_shape_metadata2R033_881A0B6978EB4286E7CFF1E27030ACACLL_px1TRts_XPXG{{(\.ptrauth)?}}", ptr [[ARGS]])
diff --git a/test/IRGen/existentials.sil b/test/IRGen/existentials.sil
index 8c3d3ebe14cac..c56b8e141628d 100644
--- a/test/IRGen/existentials.sil
+++ b/test/IRGen/existentials.sil
@@ -55,29 +55,29 @@ entry(%w : $*@sil_weak CP?, %a : $CP?):
 
   // CHECK: [[SRC_REF:%.*]] = inttoptr {{.*}} ptr
   // CHECK: [[SRC_WITNESS:%.*]] = inttoptr {{.*}} ptr
-  // CHECK: [[DEST_WITNESS_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 1
+  // CHECK: [[DEST_WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 1
   // CHECK: store ptr [[SRC_WITNESS]], ptr [[DEST_WITNESS_ADDR]]
-  // CHECK: [[DEST_REF_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 0
+  // CHECK: [[DEST_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 0
   // CHECK: call ptr @swift_weakInit(ptr returned [[DEST_REF_ADDR]], ptr [[SRC_REF]])
   store_weak %a to [init] %w : $*@sil_weak CP?
 
   // CHECK: [[SRC_REF:%.*]] = inttoptr {{.*}} ptr
   // CHECK: [[SRC_WITNESS:%.*]] = inttoptr {{.*}} ptr
-  // CHECK: [[DEST_WITNESS_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 1
+  // CHECK: [[DEST_WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 1
   // CHECK: store ptr [[SRC_WITNESS]], ptr [[DEST_WITNESS_ADDR]]
-  // CHECK: [[DEST_REF_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 0
+  // CHECK: [[DEST_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 0
   // CHECK: call ptr @swift_weakAssign(ptr returned [[DEST_REF_ADDR]], ptr [[SRC_REF]])
   store_weak %a to                  %w : $*@sil_weak CP?
 
-  // CHECK: [[SRC_REF_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 0
+  // CHECK: [[SRC_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 0
   // CHECK: [[DEST_REF:%.*]] = call ptr @swift_weakTakeStrong(ptr [[SRC_REF_ADDR]])
-  // CHECK: [[SRC_WITNESS_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 1
+  // CHECK: [[SRC_WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 1
   // CHECK: [[DEST_WITNESS:%.*]] = load ptr, ptr [[SRC_WITNESS_ADDR]]
   %b = load_weak [take] %w : $*@sil_weak CP?
 
-  // CHECK: [[SRC_REF_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 0
+  // CHECK: [[SRC_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 0
   // CHECK: [[DEST_REF:%.*]] = call ptr @swift_weakLoadStrong(ptr [[SRC_REF_ADDR]])
-  // CHECK: [[SRC_WITNESS_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 1
+  // CHECK: [[SRC_WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 1
   // CHECK: [[DEST_WITNESS:%.*]] = load ptr, ptr [[SRC_WITNESS_ADDR]]
   %c = load_weak        %w : $*@sil_weak CP?
 
diff --git a/test/IRGen/existentials_objc.sil b/test/IRGen/existentials_objc.sil
index 35bb3b5813f8b..ce06450ee54f5 100644
--- a/test/IRGen/existentials_objc.sil
+++ b/test/IRGen/existentials_objc.sil
@@ -22,11 +22,11 @@ bb0(%0 : $*Any, %1 : $T):
   return %3 : $()
 }
 
-// CHECK-DAG:   define{{( protected)?}} swiftcc void @init_opaque_existential(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %T) {{.*}} {
-// CHECK:         [[T0:%.*]] = getelementptr inbounds [[ANY:%Any]], ptr %0, i32 0, i32 1
+// CHECK-DAG:   define{{( protected)?}} swiftcc void @init_opaque_existential(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %T) {{.*}} {
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} [[ANY:%Any]], ptr %0, i32 0, i32 1
 // CHECK-NEXT:    store ptr %T, ptr [[T0]], align 8
-// CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[ANY]], ptr %0, i32 0, i32 0
-// CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[ANY]], ptr %0, i32 0, i32 0
+// CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[ANY]], ptr %0, i32 0, i32 0
+// CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[ANY]], ptr %0, i32 0, i32 0
 // CHECK-NEXT:    store ptr %1, ptr [[T0]], align 8
 // CHECK-NEXT:    ret void
 
@@ -37,7 +37,7 @@ bb0(%0 : $*Any, %1 : $*Any):
   return %3 : $()
 }
 
-// CHECK-DAG:   define{{( protected)?}} swiftcc void @take_opaque_existential(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-DAG:   define{{( protected)?}} swiftcc void @take_opaque_existential(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK: call ptr @"$sypWOb"(ptr %1, ptr %0)
 // CHECK-NEXT:    ret void
 
@@ -68,12 +68,12 @@ entry(%s : $CP):
   // CHECK: [[U2:%.*]] = alloca [[UREF]], align 8
 
   store_unowned %s to [init] %u1 : $*@sil_unowned CP
-  // CHECK: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[U1]], i32 0, i32 1
+  // CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[U1]], i32 0, i32 1
   // CHECK: store ptr %1, ptr [[T0]], align 8
-  // CHECK: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[U1]], i32 0, i32 0
+  // CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[U1]], i32 0, i32 0
   // CHECK: call ptr @swift_unknownObjectUnownedInit(ptr returned [[T0]], ptr %0)
 
-  // CHECK: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[U1]], i32 0, i32 0
+  // CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[U1]], i32 0, i32 0
   // CHECK: [[T1:%.*]] = call ptr @swift_unknownObjectUnownedLoadStrong(ptr [[T0]])
   %t = load_unowned %u1 : $*@sil_unowned CP
   // CHECK: call void @swift_unknownObjectRelease(ptr [[T1]])
@@ -105,29 +105,29 @@ entry(%w : $*@sil_weak CP?, %a : $CP?):
 
   // CHECK: [[SRC_REF:%.*]] = inttoptr {{.*}} ptr
   // CHECK: [[SRC_WITNESS:%.*]] = inttoptr {{.*}} ptr
-  // CHECK: [[DEST_WITNESS_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 1
+  // CHECK: [[DEST_WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 1
   // CHECK: store ptr [[SRC_WITNESS]], ptr [[DEST_WITNESS_ADDR]]
-  // CHECK: [[DEST_REF_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 0
+  // CHECK: [[DEST_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 0
   // CHECK: call ptr @swift_unknownObjectWeakInit(ptr returned [[DEST_REF_ADDR]], ptr [[SRC_REF]])
   store_weak %a to [init] %w : $*@sil_weak CP?
 
   // CHECK: [[SRC_REF:%.*]] = inttoptr {{.*}} ptr
   // CHECK: [[SRC_WITNESS:%.*]] = inttoptr {{.*}} ptr
-  // CHECK: [[DEST_WITNESS_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 1
+  // CHECK: [[DEST_WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 1
   // CHECK: store ptr [[SRC_WITNESS]], ptr [[DEST_WITNESS_ADDR]]
-  // CHECK: [[DEST_REF_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 0
+  // CHECK: [[DEST_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 0
   // CHECK: call ptr @swift_unknownObjectWeakAssign(ptr returned [[DEST_REF_ADDR]], ptr [[SRC_REF]])
   store_weak %a to                  %w : $*@sil_weak CP?
 
-  // CHECK: [[SRC_REF_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 0
+  // CHECK: [[SRC_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 0
   // CHECK: [[DEST_REF:%.*]] = call ptr @swift_unknownObjectWeakTakeStrong(ptr [[SRC_REF_ADDR]])
-  // CHECK: [[SRC_WITNESS_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 1
+  // CHECK: [[SRC_WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 1
   // CHECK: [[DEST_WITNESS:%.*]] = load ptr, ptr [[SRC_WITNESS_ADDR]]
   %b = load_weak [take] %w : $*@sil_weak CP?
 
-  // CHECK: [[SRC_REF_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 0
+  // CHECK: [[SRC_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 0
   // CHECK: [[DEST_REF:%.*]] = call ptr @swift_unknownObjectWeakLoadStrong(ptr [[SRC_REF_ADDR]])
-  // CHECK: [[SRC_WITNESS_ADDR:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 1
+  // CHECK: [[SRC_WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 1
   // CHECK: [[DEST_WITNESS:%.*]] = load ptr, ptr [[SRC_WITNESS_ADDR]]
   %c = load_weak        %w : $*@sil_weak CP?
 
diff --git a/test/IRGen/existentials_opaque_boxed.sil b/test/IRGen/existentials_opaque_boxed.sil
index 1315c54be3722..044b906b96f0b 100644
--- a/test/IRGen/existentials_opaque_boxed.sil
+++ b/test/IRGen/existentials_opaque_boxed.sil
@@ -46,18 +46,18 @@ entry(%0 : $*T):
 }
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} linkonce_odr hidden ptr @__swift_allocate_boxed_opaque_existential_1(ptr %0)
-// CHECK:  [[METATYPE_ADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %0, i32 0, i32 1
+// CHECK:  [[METATYPE_ADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %0, i32 0, i32 1
 // CHECK:  [[METATYPE:%.*]] = load ptr, ptr [[METATYPE_ADDR]]
 // CHECK:  [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[METATYPE]], {{(i64|i32)}} -1
 // CHECK:  [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:  [[FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+// CHECK:  [[FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
 // CHECK:  [[FLAGS:%.*]] = load i32, ptr [[FLAGS_ADDR]]
 // CHECK:  [[ISNOTINLINE:%.*]] = and i32 [[FLAGS]], 131072
 // CHECK:  [[ISINLINE:%.*]] = icmp eq i32 [[ISNOTINLINE]], 0
-// CHECK:  [[EXISTENTIAL_BUFFER:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %0, i32 0, i32 0
+// CHECK:  [[EXISTENTIAL_BUFFER:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %0, i32 0, i32 0
 // CHECK:  br i1 [[ISINLINE]], label %done, label %allocateBox
 //
 // CHECK:done:
@@ -79,8 +79,8 @@ entry(%0 : $*T):
 // CHECK-LABEL: define {{.*}} @test_init_existential_fixed
 // CHECK:  [[CONTAINER:%.*]] = alloca %T25existentials_opaque_boxed11ExistentialP
 // The first inline buffer reference is from the emitOpaqueExistentialContainerInit call.
-// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
-// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
+// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
+// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
 sil @test_init_existential_fixed : $@convention(thin) () -> () {
 entry:
   %exist_container = alloc_stack $Existential
@@ -101,10 +101,10 @@ entry:
 
 // CHECK-LABEL: define {{.*}} @test_init_existential_fixed_not_inline()
 // CHECK:  [[CONTAINER:%.*]] = alloca %T25existentials_opaque_boxed11ExistentialP
-// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
-// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
+// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
+// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
 // CHECK:  [[BOX:%.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata, i32 0, i32 2), {{(i64 48|i32 40)}}, {{(i64|i32)}} 7)
-// CHECK:  [[VALUE_ADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted{{(, \[4 x i8\])?}}, [32 x i8] }>, ptr [[BOX]], i32 0, i32 {{(1|2)}}
+// CHECK:  [[VALUE_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted{{(, \[4 x i8\])?}}, [32 x i8] }>, ptr [[BOX]], i32 0, i32 {{(1|2)}}
 // CHECK:  store ptr [[BOX]], ptr [[INLINEBUFFER]]
 // CHECK:  ret void
 sil @test_init_existential_fixed_not_inline : $@convention(thin) () -> () {
@@ -148,14 +148,14 @@ entry:
 }
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} linkonce_odr hidden void @__swift_deallocate_boxed_opaque_existential_1(ptr %0)
-// CHECK:   [[META_ADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %0, i32 0, i32 1
+// CHECK:   [[META_ADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %0, i32 0, i32 1
 // CHECK:   [[META:%.*]] = load ptr, ptr [[META_ADDR]]
 // CHECK:   [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr %2, {{(i64|i32)}} -1
 // CHECK:   [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
 // CHECK:   [[FLAGS:%.*]] = load i32, ptr [[FLAGS_ADDR]]
 // CHECK:   [[ISNOTINLINE:%.*]] = and i32 [[FLAGS]], 131072
 // CHECK:   [[ISINLINE:%.*]] = icmp eq i32 [[ISNOTINLINE]], 0
@@ -165,14 +165,14 @@ entry:
 // CHECK: ret void
 
 // CHECK:  deallocateBox:
-// CHECK:   [[BUFFER:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %0, i32 0, i32 0
+// CHECK:   [[BUFFER:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %0, i32 0, i32 0
 // CHECK:   [[REFERENCE:%.*]] = load ptr, ptr [[BUFFER]]
 // CHECK:   [[VWT_ADDR2:%.*]] = getelementptr inbounds ptr, ptr [[META]], {{(i64|i32)}} -1
 // CHECK:   [[VWT2:%.*]] = load ptr, ptr [[VWT_ADDR2]]
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR2]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT2:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[SIZE2_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT2]], i32 0, i32 8
+// CHECK:   [[SIZE2_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT2]], i32 0, i32 8
 // CHECK:   [[SIZE:%.*]] = load [[INT]], ptr [[SIZE2_ADDR]]
 // CHECK-64:[[T0:%.*]] = zext i32 [[FLAGS]] to i64
 // CHECK-64:[[ALIGNMASK:%.*]] = and i64 [[T0]], 255
@@ -188,9 +188,9 @@ entry:
 // CHECK:   ret void
 
 // CHECK-LABEL: define {{.*}} @test_open_existential_addr_immutable(ptr
-// CHECK:  [[META_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 1
+// CHECK:  [[META_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 1
 // CHECK:  [[METATYPE:%.*]] = load ptr, ptr [[META_ADDR]]
-// CHECK:  [[VWT_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 2
+// CHECK:  [[VWT_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 2
 // CHECK:  [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
 // CHECK:  [[VALUE_ADDR:%.*]] = call ptr @__swift_project_boxed_opaque_existential_1(ptr %0, ptr [[METATYPE]])
 // CHECK: ret void
@@ -207,7 +207,7 @@ bb0(%0 : $*Existential):
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
 // CHECK:   [[FLAGS:%.*]] = load i32, ptr [[FLAGS_ADDR]]
 // CHECK:   [[ISNOTINLINE:%.*]] = and i32 [[FLAGS]], 131072
 // CHECK:   [[ISINLINE:%.*]] = icmp eq i32 [[ISNOTINLINE]], 0
@@ -231,9 +231,9 @@ bb0(%0 : $*Existential):
 
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} {{.*}} @test_open_existential_addr_mutable
-// CHECK:  [[META_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 1
+// CHECK:  [[META_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 1
 // CHECK:  [[METATYPE:%.*]] = load ptr, ptr [[META_ADDR]]
-// CHECK:  [[VWT_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 2
+// CHECK:  [[VWT_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 2
 // CHECK:  [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
 // CHECK:  [[VALUE_ADDR:%.*]] = call ptr @__swift_mutable_project_boxed_opaque_existential_1(ptr %0, ptr [[METATYPE]])
 // CHECK: ret void
@@ -250,7 +250,7 @@ bb0(%0 : $*Existential):
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
 // CHECK:   [[FLAGS:%.*]] = load i32, ptr [[FLAGS_ADDR]]
 // CHECK:   [[ISNOTINLINE:%.*]] = and i32 [[FLAGS]], 131072
 // CHECK:   [[ISINLINE:%.*]] = icmp eq i32 [[ISNOTINLINE]], 0
@@ -290,15 +290,15 @@ bb0(%0 : $*OtherExistential):
 }
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} linkonce_odr hidden void @__swift_destroy_boxed_opaque_existential_1(ptr %0)
-// CHECK:  [[METADATA_ADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %0, i32 0, i32 1
+// CHECK:  [[METADATA_ADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %0, i32 0, i32 1
 // CHECK:  [[METADATA:%.*]] = load ptr, ptr [[METADATA_ADDR]]
-// CHECK:  [[BUFFER_ADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %0, i32 0, i32 0
+// CHECK:  [[BUFFER_ADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %0, i32 0, i32 0
 // CHECK:  [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[METADATA]], {{(i64|i32)}} -1
 // CHECK:  [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:  [[FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+// CHECK:  [[FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
 // CHECK:  [[FLAGS:%.*]] = load i32, ptr [[FLAGS_ADDR]]
 // CHECK:  [[ISNOTINLINE:%.*]] = and i32 [[FLAGS]], 131072
 // CHECK:  [[ISINLINE:%.*]] = icmp eq i32 [[ISNOTINLINE]], 0
@@ -349,11 +349,11 @@ bb0(%0 : $*OtherExistential):
 // CHECK:  br i1 [[SELFASSIGN]], label %done, label %cont
 //
 // CHECK: cont:
-// CHECK:   [[DEST_BUFFERADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %0, i32 0, i32 0
-// CHECK:   [[SRC_BUFFERADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %1, i32 0, i32 0
-// CHECK:   [[DEST_TYPEADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %0, i32 0, i32 1
+// CHECK:   [[DEST_BUFFERADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %0, i32 0, i32 0
+// CHECK:   [[SRC_BUFFERADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %1, i32 0, i32 0
+// CHECK:   [[DEST_TYPEADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %0, i32 0, i32 1
 // CHECK:   [[DEST_TYPE:%.*]] = load ptr, ptr [[DEST_TYPEADDR]]
-// CHECK:   [[SRC_TYPEADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %1, i32 0, i32 1
+// CHECK:   [[SRC_TYPEADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %1, i32 0, i32 1
 // CHECK:   [[SRC_TYPE:%.*]] = load ptr, ptr [[SRC_TYPEADDR]]
 // CHECK:   [[ISSAME:%.*]] = icmp eq ptr [[DEST_TYPE]], [[SRC_TYPE]]
 // CHECK:   br i1 [[ISSAME]], label %match, label %no-match
@@ -364,7 +364,7 @@ bb0(%0 : $*OtherExistential):
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
 // CHECK:   [[FLAGS:%.*]] = load i32, ptr [[FLAGS_ADDR]]
 // CHECK:   [[ISNOTINLINE:%.*]] = and i32 [[FLAGS]], 131072
 // CHECK:   [[ISINLINE:%.*]] = icmp eq i32 [[ISNOTINLINE]], 0
@@ -391,8 +391,8 @@ bb0(%0 : $*OtherExistential):
 
 // CHECK: no-match:
 // CHECK:   store ptr [[SRC_TYPE]], ptr [[DEST_TYPEADDR]]
-// CHECK:   [[DEST_PWT_ADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %0, i32 0, i32 2
-// CHECK:   [[SRC_PWT_ADDR:%.*]] = getelementptr inbounds %__opaque_existential_type_1, ptr %1, i32 0, i32 2
+// CHECK:   [[DEST_PWT_ADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %0, i32 0, i32 2
+// CHECK:   [[SRC_PWT_ADDR:%.*]] = getelementptr inbounds{{.*}} %__opaque_existential_type_1, ptr %1, i32 0, i32 2
 // CHECK:   [[SRC_PTW:%.*]] = load ptr, ptr [[SRC_PWT_ADDR]]
 // CHECK:   store ptr [[SRC_PTW]], ptr [[DEST_PWT_ADDR]]
 // CHECK:   [[DEST_VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[DEST_TYPE]], {{(i64|i32)}} -1
@@ -400,7 +400,7 @@ bb0(%0 : $*OtherExistential):
 // CHECK-arm64e-NEXT: ptrtoint ptr [[DEST_VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[DEST_VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[DEST_FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[DEST_VWT]], i32 0, i32 10
+// CHECK:   [[DEST_FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[DEST_VWT]], i32 0, i32 10
 // CHECK:   [[DEST_FLAGS:%.*]] = load i32, ptr [[DEST_FLAGS_ADDR]]
 // CHECK:   [[DEST_ISNOTINLINE:%.*]] = and i32 [[DEST_FLAGS]], 131072
 // CHECK:   [[DEST_ISINLINE:%.*]] = icmp eq i32 [[DEST_ISNOTINLINE]], 0
@@ -409,7 +409,7 @@ bb0(%0 : $*OtherExistential):
 // CHECK-arm64e-NEXT: ptrtoint ptr [[SRC_VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[SRC_VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[SRC_FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[SRC_VWT]], i32 0, i32 10
+// CHECK:   [[SRC_FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[SRC_VWT]], i32 0, i32 10
 // CHECK:   [[SRC_FLAGS:%.*]] = load i32, ptr [[SRC_FLAGS_ADDR]]
 // CHECK:   [[SRC_ISNOTINLINE:%.*]] = and i32 [[SRC_FLAGS]], 131072
 // CHECK:   [[SRC_ISINLINE:%.*]] = icmp eq i32 [[SRC_ISNOTINLINE]], 0
@@ -536,16 +536,16 @@ bb0(%0 : $*OtherExistential):
 // CHECK:   call ptr @"$s25existentials_opaque_boxed11Existential_pWOc"(ptr %0, ptr [[LOCAL]])
 // CHECK:   ret void
 // CHECK-LABEL: define linkonce_odr hidden ptr @"$s25existentials_opaque_boxed11Existential_pWOc"(ptr %0, ptr %1)
-// CHECK:   [[TYPE_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 1
+// CHECK:   [[TYPE_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 1
 // CHECK:   [[ARG_TYPE:%.*]] = load ptr, ptr [[TYPE_ADDR]]
-// CHECK:   [[LOCAL_TYPE_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %1, i32 0, i32 1
+// CHECK:   [[LOCAL_TYPE_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %1, i32 0, i32 1
 // CHECK:   store ptr [[ARG_TYPE]], ptr [[LOCAL_TYPE_ADDR]]
-// CHECK:   [[PWT_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 2
+// CHECK:   [[PWT_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 2
 // CHECK:   [[PWT:%.*]] = load ptr, ptr [[PWT_ADDR]]
-// CHECK:   [[LOCAL_PWT_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %1, i32 0, i32 2
+// CHECK:   [[LOCAL_PWT_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %1, i32 0, i32 2
 // CHECK:   store ptr [[PWT]], ptr [[LOCAL_PWT_ADDR]]
-// CHECK:   [[BUFFER_ARG_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 0
-// CHECK:   [[BUFFER_LOCAL_ADDR:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr %1, i32 0, i32 0
+// CHECK:   [[BUFFER_ARG_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %0, i32 0, i32 0
+// CHECK:   [[BUFFER_LOCAL_ADDR:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr %1, i32 0, i32 0
 // CHECK:   [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[ARG_TYPE]], {{(i64|i32)}} -1
 // CHECK:   [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
@@ -581,8 +581,8 @@ struct FixedOveralign : Existential {
 
 // CHECK-LABEL: define {{.*}} @test_init_existential_fixed_align_not_inline()
 // CHECK:  [[CONTAINER:%.*]] = alloca %T25existentials_opaque_boxed11ExistentialP
-// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
-// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
+// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
+// CHECK:  [[INLINEBUFFER:%.*]] = getelementptr inbounds{{.*}} %T25existentials_opaque_boxed11ExistentialP, ptr [[CONTAINER]], i32 0, i32 0
 // CHECK:  [[BOX:%.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata.4, i32 0, i32 2), {{(i64|i32)}} 32, {{(i64|i32)}} 15)
 // CHECK:  [[VALUE_ADDR:%.*]] = getelementptr inbounds {{.*}}, ptr [[BOX]], i32 0, i32 {{(1|2)}}
 // CHECK:  store ptr [[BOX]], ptr [[INLINEBUFFER]]
diff --git a/test/IRGen/extern_c_abitypes.swift b/test/IRGen/extern_c_abitypes.swift
index 34a9c818eb092..5e658f36bf5d7 100644
--- a/test/IRGen/extern_c_abitypes.swift
+++ b/test/IRGen/extern_c_abitypes.swift
@@ -101,12 +101,12 @@ func test() {
 
   // assume %struct.c_struct and %TSo8c_structV have compatible layout
   //
-  // CHECK-x86_64: call void     @c_roundtrip_c_struct(ptr noalias nocapture sret(%TSo8c_structV) {{.*}}, ptr{{( byval\(%struct.c_struct\))?}}[[ALIGN:(align [0-9]+)?]] {{.*}})
-  // CHECK-x86_64: call void @swift_roundtrip_c_struct(ptr noalias nocapture sret(%TSo8c_structV)   {{.*}}, ptr{{( byval\(%TSo8c_structV\))?}}[[ALIGN]] {{.*}})
-  // CHECK-arm64:  call void     @c_roundtrip_c_struct(ptr noalias nocapture sret(%TSo8c_structV) {{.*}}, ptr{{( byval\(%struct.c_struct\))?}}[[ALIGN:(align [0-9]+)?]] {{.*}})
-  // CHECK-arm64:  call void @swift_roundtrip_c_struct(ptr noalias nocapture sret(%TSo8c_structV)   {{.*}}, ptr{{( byval\(%TSo8c_structV\))?}}[[ALIGN]] {{.*}})
-  // CHECK-wasm32: call void     @c_roundtrip_c_struct(ptr noalias nocapture sret(%TSo8c_structV) {{.*}}, ptr{{( byval\(%struct.c_struct\))?}}[[ALIGN:(align [0-9]+)?]] {{.*}})
-  // CHECK-wasm32: call void @swift_roundtrip_c_struct(ptr noalias nocapture sret(%TSo8c_structV)   {{.*}}, ptr{{( byval\(%TSo8c_structV\))?}}[[ALIGN]] {{.*}})
+  // CHECK-x86_64: call void     @c_roundtrip_c_struct(ptr noalias{{( nocapture)?}} sret(%TSo8c_structV){{( captures\(none\))?}} {{.*}}, ptr{{( byval\(%struct.c_struct\))?}}[[ALIGN:(align [0-9]+)?]] {{.*}})
+  // CHECK-x86_64: call void @swift_roundtrip_c_struct(ptr noalias{{( nocapture)?}} sret(%TSo8c_structV){{( captures\(none\))?}}   {{.*}}, ptr{{( byval\(%TSo8c_structV\))?}}[[ALIGN]] {{.*}})
+  // CHECK-arm64:  call void     @c_roundtrip_c_struct(ptr noalias{{( nocapture)?}} sret(%TSo8c_structV){{( captures\(none\))?}} {{.*}}, ptr{{( byval\(%struct.c_struct\))?}}[[ALIGN:(align [0-9]+)?]] {{.*}})
+  // CHECK-arm64:  call void @swift_roundtrip_c_struct(ptr noalias{{( nocapture)?}} sret(%TSo8c_structV){{( captures\(none\))?}}   {{.*}}, ptr{{( byval\(%TSo8c_structV\))?}}[[ALIGN]] {{.*}})
+  // CHECK-wasm32: call void     @c_roundtrip_c_struct(ptr noalias{{( nocapture)?}} sret(%TSo8c_structV){{( captures\(none\))?}} {{.*}}, ptr{{( byval\(%struct.c_struct\))?}}[[ALIGN:(align [0-9]+)?]] {{.*}})
+  // CHECK-wasm32: call void @swift_roundtrip_c_struct(ptr noalias{{( nocapture)?}} sret(%TSo8c_structV){{( captures\(none\))?}}   {{.*}}, ptr{{( byval\(%TSo8c_structV\))?}}[[ALIGN]] {{.*}})
   // CHECK-armv7k: call [3 x i32]     @c_roundtrip_c_struct([3 x i32] {{.*}})
   // CHECK-armv7k: call [3 x i32] @swift_roundtrip_c_struct([3 x i32] {{.*}})
   var c_struct_val = c_struct(foo: 496, bar: 28, baz: 8)
diff --git a/test/IRGen/fixed_layout_class.swift b/test/IRGen/fixed_layout_class.swift
index 202dc9e4af623..294188e8595f4 100644
--- a/test/IRGen/fixed_layout_class.swift
+++ b/test/IRGen/fixed_layout_class.swift
@@ -12,7 +12,7 @@ import fixed_layout_class
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s16class_resilience20useRootClassPropertyyy013fixed_layout_A0026OutsideParentWithResilientF0CF"(ptr %0)
 public func useRootClassProperty(_ o: OutsideParentWithResilientProperty) {
-  // CHECK: getelementptr inbounds %T18fixed_layout_class34OutsideParentWithResilientPropertyC, ptr %0, i32 0, i32 1
+  // CHECK: getelementptr inbounds{{.*}} %T18fixed_layout_class34OutsideParentWithResilientPropertyC, ptr %0, i32 0, i32 1
   let a = o.p
   // CHECK: load [[INT]], ptr @"$s18fixed_layout_class34OutsideParentWithResilientPropertyC1s16resilient_struct4SizeVvpWvd"
   let b = o.s
@@ -23,9 +23,9 @@ public func useRootClassProperty(_ o: OutsideParentWithResilientProperty) {
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s16class_resilience19useSubclassPropertyyy013fixed_layout_A012OutsideChildCF"(ptr %0)
 public func useSubclassProperty(_ o: OutsideChild) {
-  // CHECK: getelementptr inbounds %T18fixed_layout_class13OutsideParentC, ptr {{%[0-9]+}}, i32 0, i32 1
+  // CHECK: getelementptr inbounds{{.*}} %T18fixed_layout_class13OutsideParentC, ptr {{%[0-9]+}}, i32 0, i32 1
   let a = o.property
-  // CHECK: getelementptr inbounds %T18fixed_layout_class12OutsideChildC, ptr %0, i32 0, i32 2
+  // CHECK: getelementptr inbounds{{.*}} %T18fixed_layout_class12OutsideChildC, ptr %0, i32 0, i32 2
   let b = o.childProperty
   // CHECK: ret void
 }
@@ -51,7 +51,7 @@ public func useGenericRootClassProperty<A>(_ o: GenericOutsideParent<A>) {
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s16class_resilience27useGenericRootClassPropertyyy013fixed_layout_A00D13OutsideParentCySiGF"(ptr %0)
 public func useGenericRootClassProperty(_ o: GenericOutsideParent<Int>) {
-  // CHECK: getelementptr inbounds %T18fixed_layout_class20GenericOutsideParentCySiG, ptr %0, i32 0, i32 1
+  // CHECK: getelementptr inbounds{{.*}} %T18fixed_layout_class20GenericOutsideParentCySiG, ptr %0, i32 0, i32 1
   let a = o.property
 
   // CHECK: ret void
@@ -87,10 +87,10 @@ public func useGenericSubclassProperty<A>(_ o: GenericOutsideChild<A>) {
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s16class_resilience26useGenericSubclassPropertyyy013fixed_layout_A00D12OutsideChildCySiGF"(ptr %0)
 public func useGenericSubclassProperty(_ o: GenericOutsideChild<Int>) {
-  // CHECK: getelementptr inbounds %T18fixed_layout_class20GenericOutsideParentCySiG, ptr %0, i32 0, i32 1
+  // CHECK: getelementptr inbounds{{.*}} %T18fixed_layout_class20GenericOutsideParentCySiG, ptr %0, i32 0, i32 1
   let a = o.property
 
-  // CHECK: getelementptr inbounds %T18fixed_layout_class19GenericOutsideChildCySiG, ptr %0, i32 0, i32 2
+  // CHECK: getelementptr inbounds{{.*}} %T18fixed_layout_class19GenericOutsideChildCySiG, ptr %0, i32 0, i32 2
   let b = o.childProperty
 
   // CHECK: ret void
diff --git a/test/IRGen/fixed_size_buffer_peepholes.sil b/test/IRGen/fixed_size_buffer_peepholes.sil
index d155865530ac2..378f5c92032d2 100644
--- a/test/IRGen/fixed_size_buffer_peepholes.sil
+++ b/test/IRGen/fixed_size_buffer_peepholes.sil
@@ -5,7 +5,7 @@ import Builtin
 protocol P {}
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @dont_crash(
-// CHECK:  [[TYPE_ADDR:%.*]] = getelementptr inbounds %T27fixed_size_buffer_peepholes1PP, ptr %0, i32 0, i32 1
+// CHECK:  [[TYPE_ADDR:%.*]] = getelementptr inbounds{{.*}} %T27fixed_size_buffer_peepholes1PP, ptr %0, i32 0, i32 1
 // CHECK:  [[TYPE:%.*]] = load ptr, ptr [[TYPE_ADDR]]
 // CHECK:  call {{.*}} @__swift_project_boxed_opaque_existential_1
 // CHECK:  [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[TYPE]], {{(i64|i32)}} -1
diff --git a/test/IRGen/fixlifetime.sil b/test/IRGen/fixlifetime.sil
index c6c971758c49e..dcf0d96206e31 100644
--- a/test/IRGen/fixlifetime.sil
+++ b/test/IRGen/fixlifetime.sil
@@ -8,7 +8,7 @@
 // unnecessary.
 // ONONE-NOT: @__swift_fixLifetime
 
-// CHECK-objc-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @test(ptr %0, ptr %1, ptr %2, ptr %3, ptr %4, ptr noalias nocapture dereferenceable({{.*}}) %5, {{(i64|i32)}} %6, {{(i64|i32)}} %7) {{.*}} {
+// CHECK-objc-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @test(ptr %0, ptr %1, ptr %2, ptr %3, ptr %4, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %5, {{(i64|i32)}} %6, {{(i64|i32)}} %7) {{.*}} {
 // CHECK-objc: entry:
 // CHECK-objc:  call void @__swift_fixLifetime(ptr
 // CHECK-objc:  call void @__swift_fixLifetime(ptr
@@ -20,7 +20,7 @@
 // CHECK-objc:  call void @__swift_fixLifetime(ptr [[TEMP]])
 // CHECK-objc:  call void @__swift_fixLifetime(ptr
 
-// CHECK-native-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @test(ptr %0, ptr %1, ptr %2, ptr %3, ptr %4, ptr noalias nocapture dereferenceable({{.*}}) %5, {{(i64|i32)}} %6, {{(i64|i32)}} %7) {{.*}} {
+// CHECK-native-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @test(ptr %0, ptr %1, ptr %2, ptr %3, ptr %4, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %5, {{(i64|i32)}} %6, {{(i64|i32)}} %7) {{.*}} {
 // CHECK-native: entry:
 // CHECK-native:  call void @__swift_fixLifetime(ptr
 // CHECK-native:  call void @__swift_fixLifetime(ptr
diff --git a/test/IRGen/framepointer.sil b/test/IRGen/framepointer.sil
index 2ef0a5c2b7f6a..39202c14fa5b7 100644
--- a/test/IRGen/framepointer.sil
+++ b/test/IRGen/framepointer.sil
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -primary-file %s -emit-ir | %FileCheck %s -check-prefix CHECK --check-prefix=CHECK-%target-abi
+// RUN: %target-swift-frontend -primary-file %s -emit-ir | %FileCheck %s -check-prefix CHECK --check-prefix=CHECK-%target-abi --check-prefix=CHECK-%target-abi-%target-os
 // RUN: %target-swift-frontend -primary-file %s -emit-ir -Xcc -mno-omit-leaf-frame-pointer | %FileCheck %s -check-prefix CHECK-ALL --check-prefix=CHECK-%target-abi-ALL
 // RUN: %target-swift-frontend -primary-file %s -S | %FileCheck %s  --check-prefix=CHECKASM --check-prefix=CHECKASM-%target-os-%target-cpu
 // RUN: %target-swift-frontend -primary-file %s -emit-ir -Xcc -momit-leaf-frame-pointer | %FileCheck %s -check-prefix LEAF --check-prefix=LEAF-%target-abi
@@ -31,9 +31,12 @@ entry(%i : $Int32):
 // CHECK: entry:
 // CHECK:   %1 = call swiftcc i32 @leaf_function_no_frame_pointer(i32 %0)
 // CHECK:   ret i32 %1
-// CHECK: }
 
-// CHECK-SYSV: attributes [[ATTR]] = { {{.*}}"frame-pointer"="all"
+// CHECK-SYSV: }
+// CHECK-SYSV-macosx: attributes [[ATTR]] = { {{.*}}"frame-pointer"="all"
+// CHECK-SYSV-linux-gnu: attributes [[ATTR]] = { {{.*}}"frame-pointer"="all"
+// CHECK-SYSV-linux-android: attributes [[ATTR]] = { {{.*}}"frame-pointer"="non-leaf"
+// CHECK-WIN: }
 // CHECK-WIN: attributes [[ATTR]] = { {{.*}}
 
 // CHECK-ALL: define{{.*}} swiftcc i32 @leaf_function_no_frame_pointer(i32 %0) [[ATTR:#.*]] {
diff --git a/test/IRGen/function_param_convention.sil b/test/IRGen/function_param_convention.sil
index 124b964fefd72..6457b11e44ec6 100644
--- a/test/IRGen/function_param_convention.sil
+++ b/test/IRGen/function_param_convention.sil
@@ -10,7 +10,7 @@ struct X {
 // Make sure we can irgen a SIL function with various parameter attributes
 // without choking. This is just a basic reality check.
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @foo(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1, ptr nocapture dereferenceable({{.*}}) %2, ptr noalias nocapture dereferenceable({{.*}}) %3, i32 %4, i32 %5, i32 %6) {{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @foo(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %2, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %3, i32 %4, i32 %5, i32 %6) {{.*}} {
 
 sil @foo : $@convention(thin) (@in X, @inout X, @in_guaranteed X, @owned X, X, @guaranteed X) -> @out X {
 bb0(%0 : $*X, %1 : $*X, %2 : $*X, %3 : $*X, %4 : $X, %5 : $X, %6 : $X):
diff --git a/test/IRGen/function_types.sil b/test/IRGen/function_types.sil
index c2d022bd9ba32..dd4eadcc3a2fb 100644
--- a/test/IRGen/function_types.sil
+++ b/test/IRGen/function_types.sil
@@ -52,9 +52,9 @@ struct X {}
 
 sil @out_void_return : $@convention(thin) () -> @out X
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @use_void_return_value(ptr noalias nocapture sret({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @use_void_return_value(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0) {{.*}} {
 // CHECK-NEXT:  entry:
-// CHECK-NEXT:    call swiftcc void @out_void_return(ptr noalias nocapture sret({{.*}}) %0)
+// CHECK-NEXT:    call swiftcc void @out_void_return(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0)
 // CHECK-NEXT:    ret void
 // CHECK-NEXT:  }
 sil @use_void_return_value : $@convention(thin) () -> @out X {
diff --git a/test/IRGen/generic_casts.swift b/test/IRGen/generic_casts.swift
index edb132269d1f4..7cf65d945d0f5 100644
--- a/test/IRGen/generic_casts.swift
+++ b/test/IRGen/generic_casts.swift
@@ -39,12 +39,12 @@ func allToInt<T>(_ x: T) -> Int {
   // CHECK: [[INT_TEMP:%.*]] = alloca %TSi,
   // CHECK: [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr %T, i64 -1
   // CHECK: [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
-  // CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+  // CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
   // CHECK: [[SIZE:%.*]] = load i64, ptr [[SIZE_ADDR]]
   // CHECK: [[T_ALLOCA:%.*]] = alloca i8, {{.*}} [[SIZE]], align 16
   // CHECK: [[TEMP:%.*]] = call ptr {{.*}}(ptr noalias [[T_ALLOCA]], ptr noalias %0, ptr %T)
   // CHECK: call zeroext i1 @swift_dynamicCast(ptr [[INT_TEMP]], ptr [[T_ALLOCA]], ptr %T, ptr @"$sSiN", i64 7)
-  // CHECK: [[T0:%.*]] = getelementptr inbounds %TSi, ptr [[INT_TEMP]], i32 0, i32 0
+  // CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[INT_TEMP]], i32 0, i32 0
   // CHECK: [[INT_RESULT:%.*]] = load i64, ptr [[T0]],
   // CHECK: ret i64 [[INT_RESULT]]
 }
@@ -52,13 +52,13 @@ func allToInt<T>(_ x: T) -> Int {
 // CHECK: define hidden swiftcc void @"$s13generic_casts8intToAllyxSilF"(ptr noalias sret({{.*}}) %0, i64 %1, ptr %T) {{.*}} {
 func intToAll<T>(_ x: Int) -> T {
   // CHECK: [[INT_TEMP:%.*]] = alloca %TSi,
-  // CHECK: [[T0:%.*]] = getelementptr inbounds %TSi, ptr [[INT_TEMP]], i32 0, i32 0
+  // CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[INT_TEMP]], i32 0, i32 0
   // CHECK: store i64 %1, ptr [[T0]],
   // CHECK: call zeroext i1 @swift_dynamicCast(ptr %0, ptr [[INT_TEMP]], ptr @"$sSiN", ptr %T, i64 7)
   return x as! T
 }
 
-// CHECK: define hidden swiftcc i64 @"$s13generic_casts8anyToIntySiypF"(ptr noalias nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK: define hidden swiftcc i64 @"$s13generic_casts8anyToIntySiypF"(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 func anyToInt(_ x: Any) -> Int {
   return x as! Int
 }
@@ -104,7 +104,7 @@ func classExistentialToOpaqueArchetype<T>(_ x: ObjCProto1) -> T {
 protocol P {}
 protocol Q {}
 
-// CHECK: define hidden swiftcc void @"$s13generic_casts19compositionToMemberyAA1P_pAaC_AA1QpF{{.*}}"(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK: define hidden swiftcc void @"$s13generic_casts19compositionToMemberyAA1P_pAaC_AA1QpF{{.*}}"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 func compositionToMember(_ a: P & Q) -> P {
   return a
 }
diff --git a/test/IRGen/generic_classes.sil b/test/IRGen/generic_classes.sil
index e21c9b8006bd5..42638f18799d6 100644
--- a/test/IRGen/generic_classes.sil
+++ b/test/IRGen/generic_classes.sil
@@ -274,7 +274,7 @@ entry:
 
 // RootGeneric.x has fixed layout
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc i8 @RootGeneric_concrete_fragile_dependent_member_access_x
-// CHECK:   getelementptr inbounds [[ROOTGENERIC]], ptr %0, i32 0, i32 1
+// CHECK:   getelementptr inbounds{{.*}} [[ROOTGENERIC]], ptr %0, i32 0, i32 1
 sil @RootGeneric_concrete_fragile_dependent_member_access_x : $<F> (RootGeneric<F>) -> UInt8 {
 entry(%c : $RootGeneric<F>):
   %p = ref_element_addr %c : $RootGeneric<F>, #RootGeneric.x
@@ -321,7 +321,7 @@ entry(%c : $RootGeneric<F>):
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i8 @RootGeneric_subst_concrete_fragile_dependent_member_access_z
 // CHECK:   [[Z_ADDR:%.*]] = getelementptr inbounds {{.*}}, ptr %0, i32 0, i32 4
-// CHECK:   [[T0:%.*]] = getelementptr inbounds %Ts5UInt8V, ptr [[Z_ADDR]], i32 0, i32 0
+// CHECK:   [[T0:%.*]] = getelementptr inbounds{{.*}} %Ts5UInt8V, ptr [[Z_ADDR]], i32 0, i32 0
 // CHECK:   load i8, ptr [[T0]], align
 sil @RootGeneric_subst_concrete_fragile_dependent_member_access_z : $(RootGeneric<Int>) -> UInt8 {
 entry(%c : $RootGeneric<Int>):
@@ -377,7 +377,7 @@ entry(%c : $RootGeneric<Int32>):
 //   Initialize our own dependent field offsets.
 // CHECK-objc:   [[OFFSETS:%.*]] = getelementptr inbounds i64, ptr [[METADATA]], i64 20
 // CHECK-native: [[OFFSETS:%.*]] = getelementptr inbounds i64, ptr [[METADATA]], i64 17
-// CHECK:   [[FIELDS_ADDR:%.*]] = getelementptr inbounds [1 x ptr], ptr %classFields, i32 0, i32 0
+// CHECK:   [[FIELDS_ADDR:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %classFields, i32 0, i32 0
 // CHECK:   [[T0:%.*]] = call{{( tail)?}} swiftcc %swift.metadata_response @swift_checkMetadataState(i64 319, ptr %B)
 // CHECK:   [[B_CHECKED:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 // CHECK:   [[B_STATUS:%.*]] = extractvalue %swift.metadata_response [[T0]], 1
diff --git a/test/IRGen/generic_metatypes.swift b/test/IRGen/generic_metatypes.swift
index d27fe84c46160..8265c0858dda5 100644
--- a/test/IRGen/generic_metatypes.swift
+++ b/test/IRGen/generic_metatypes.swift
@@ -58,13 +58,13 @@ func genericMetatypes<T, U>(_ t: T.Type, _ u: U.Type) {}
 
 protocol Bas {}
 
-// CHECK: define hidden swiftcc { ptr, ptr } @"$s17generic_metatypes14protocolTypeof{{.*}}"(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK: define hidden swiftcc { ptr, ptr } @"$s17generic_metatypes14protocolTypeof{{.*}}"(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 func protocolTypeof(_ x: Bas) -> Bas.Type {
-  // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds %T17generic_metatypes3BasP, ptr [[X:%.*]], i32 0, i32 1
+  // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds{{.*}} %T17generic_metatypes3BasP, ptr [[X:%.*]], i32 0, i32 1
   // CHECK: [[METADATA:%.*]] = load ptr, ptr [[METADATA_ADDR]]
   // CHECK: [[VALUE_ADDR:%.*]] = call ptr @__swift_project_boxed_opaque_existential_1(ptr [[X]], ptr [[METADATA]])
   // CHECK: [[METATYPE:%.*]] = call ptr @swift_getDynamicType(ptr [[VALUE_ADDR]], ptr [[METADATA]], i1 true)
-  // CHECK: [[WTABLE_ADDR:%.*]] = getelementptr inbounds %T17generic_metatypes3BasP, ptr %0, i32 0, i32 2
+  // CHECK: [[WTABLE_ADDR:%.*]] = getelementptr inbounds{{.*}} %T17generic_metatypes3BasP, ptr %0, i32 0, i32 2
   // CHECK: [[WTABLE:%.*]] = load ptr, ptr [[WTABLE_ADDR]]
   // CHECK-NOT: call void @__swift_destroy_boxed_opaque_existential_1(ptr %0)
   // CHECK: [[T0:%.*]] = insertvalue { ptr, ptr } undef, ptr [[METATYPE]], 0
diff --git a/test/IRGen/generic_metatypes_future.swift b/test/IRGen/generic_metatypes_future.swift
index f1492f3c9f46e..5f72df18e5f2c 100644
--- a/test/IRGen/generic_metatypes_future.swift
+++ b/test/IRGen/generic_metatypes_future.swift
@@ -59,13 +59,13 @@ func genericMetatypes<T, U>(_ t: T.Type, _ u: U.Type) {}
 
 protocol Bas {}
 
-// CHECK: define hidden swiftcc { ptr, ptr } @"$s17generic_metatypes14protocolTypeof{{.*}}"(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK: define hidden swiftcc { ptr, ptr } @"$s17generic_metatypes14protocolTypeof{{.*}}"(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 func protocolTypeof(_ x: Bas) -> Bas.Type {
-  // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds %T17generic_metatypes3BasP, ptr [[X:%.*]], i32 0, i32 1
+  // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds{{.*}} %T17generic_metatypes3BasP, ptr [[X:%.*]], i32 0, i32 1
   // CHECK: [[METADATA:%.*]] = load ptr, ptr [[METADATA_ADDR]]
   // CHECK: [[VALUE_ADDR:%.*]] = call ptr @__swift_project_boxed_opaque_existential_1(ptr [[X]], ptr [[METADATA]])
   // CHECK: [[METATYPE:%.*]] = call ptr @swift_getDynamicType(ptr [[VALUE_ADDR]], ptr [[METADATA]], i1 true)
-  // CHECK: [[WTABLE_ADDR:%.*]] = getelementptr inbounds %T17generic_metatypes3BasP, ptr %0, i32 0, i32 2
+  // CHECK: [[WTABLE_ADDR:%.*]] = getelementptr inbounds{{.*}} %T17generic_metatypes3BasP, ptr %0, i32 0, i32 2
   // CHECK: [[WTABLE:%.*]] = load ptr, ptr [[WTABLE_ADDR]]
   // CHECK-NOT: call void @__swift_destroy_boxed_opaque_existential_1(ptr %0)
   // CHECK: [[T0:%.*]] = insertvalue { ptr, ptr } undef, ptr [[METATYPE]], 0
diff --git a/test/IRGen/generic_ternary.swift b/test/IRGen/generic_ternary.swift
index f44288913f1b2..b00c4f78d7951 100644
--- a/test/IRGen/generic_ternary.swift
+++ b/test/IRGen/generic_ternary.swift
@@ -4,7 +4,7 @@
 
 // <rdar://problem/13793646>
 struct OptionalStreamAdaptor<T : IteratorProtocol> {
-  // CHECK: define hidden swiftcc void @"$s15generic_ternary21OptionalStreamAdaptorV4next{{[_0-9a-zA-Z]*}}F"(ptr noalias sret({{.*}}) %0, ptr %"OptionalStreamAdaptor<T>", ptr nocapture swiftself dereferenceable({{.*}}) %1)
+  // CHECK: define hidden swiftcc void @"$s15generic_ternary21OptionalStreamAdaptorV4next{{[_0-9a-zA-Z]*}}F"(ptr noalias sret({{.*}}) %0, ptr %"OptionalStreamAdaptor<T>", ptr{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{.*}}) %1)
   mutating
   func next() -> Optional<T.Element> {
     return x[0].next()
diff --git a/test/IRGen/generic_tuples.swift b/test/IRGen/generic_tuples.swift
index b1ad0a699daa8..322112397c6c1 100644
--- a/test/IRGen/generic_tuples.swift
+++ b/test/IRGen/generic_tuples.swift
@@ -3,7 +3,8 @@
 // Make sure that optimization passes don't choke on storage types for generic tuples
 // RUN: %target-swift-frontend -module-name generic_tuples -emit-ir -O %s
 
-// REQUIRES: CPU=x86_64
+// REQUIRES: PTRSIZE=64
+// UNSUPPORTED: CPU=arm64e
 
 // CHECK-DAG: [[OPAQUE:%swift.opaque]] = type opaque
 // CHECK-DAG: [[TUPLE_TYPE:%swift.tuple_type]] = type { %swift.type, i64, ptr, [0 x %swift.tuple_element_type] }
@@ -15,7 +16,7 @@ func dup<T>(_ x: T) -> (T, T) { var x = x; return (x,x) }
 //   Allocate a local variable for 'x'.
 // CHECK: [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr %T, i64 -1
 // CHECK: [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
-// CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+// CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
 // CHECK: [[SIZE:%.*]] = load i64, ptr [[SIZE_ADDR]]
 // CHECK: [[X_ALLOCA:%.*]] = alloca i8, {{.*}} [[SIZE]], align 16
 // Debug info shadow copy.
@@ -26,9 +27,10 @@ func dup<T>(_ x: T) -> (T, T) { var x = x; return (x,x) }
 //   Copy 'x' into the first result.
 // CHECK-NEXT: call ptr [[WITNESS]](ptr noalias %0, ptr noalias [[X_ALLOCA]], ptr %T)
 //   Copy 'x' into the second element.
-// CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[VWT]], i32 4
-// CHECK-NEXT: [[WITNESS:%.*]] = load ptr, ptr [[WITNESS_ADDR]], align 8
 // CHECK-NEXT: call ptr [[WITNESS]](ptr noalias %1, ptr noalias [[X_ALLOCA]], ptr %T)
+// CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[VWT]], i32 1
+// CHECK-NEXT: [[DESTROYWITNESS:%.*]] = load ptr, ptr [[WITNESS_ADDR]], align 8
+// CHECK-NEXT: call void [[DESTROYWITNESS]](ptr noalias [[X_ALLOCA]],
 
 struct S {}
 
diff --git a/test/IRGen/global_resilience.sil b/test/IRGen/global_resilience.sil
index 4d655b1683278..b8a50eff40e25 100644
--- a/test/IRGen/global_resilience.sil
+++ b/test/IRGen/global_resilience.sil
@@ -39,14 +39,6 @@ public struct LargeResilientStruct {
 // CHECK: @largeGlobal = {{(dllexport )?}}{{(protected )?}}global [[BUFFER]] zeroinitializer
 sil_global [let] @largeGlobal : $LargeResilientStruct
 
-//
-// Size is known in this resilience domain, and global is hidden,
-// so allocate it directly.
-//
-
-// CHECK: @fixedGlobal = hidden global %T17global_resilience20LargeResilientStructV zeroinitializer
-sil_global hidden @fixedGlobal : $LargeResilientStruct
-
 //
 // Unknown size -- must call value witness functions for buffer
 // management.
@@ -55,6 +47,14 @@ sil_global hidden @fixedGlobal : $LargeResilientStruct
 // CHECK: @otherGlobal = {{(dllexport )?}}{{(protected )?}}global [[BUFFER]] zeroinitializer
 sil_global [let] @otherGlobal : $Size
 
+//
+// Size is known in this resilience domain, and global is hidden,
+// so allocate it directly.
+//
+
+// CHECK: @fixedGlobal = hidden global %T17global_resilience20LargeResilientStructV zeroinitializer
+sil_global hidden @fixedGlobal : $LargeResilientStruct
+
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @testSmallGlobal()
 sil @testSmallGlobal : $@convention(thin) () -> Int32 {
 bb0:
@@ -94,7 +94,7 @@ bb0:
 
   %addr = global_addr @fixedGlobal : $*LargeResilientStruct
 
-  // CHECK: [[VALUE:%.*]] = load i64, ptr getelementptr inbounds (%T17global_resilience20LargeResilientStructV, ptr @fixedGlobal, i32 0, i32 1)
+  // CHECK: [[VALUE:%.*]] = load i64, ptr getelementptr inbounds{{.*}} (%T17global_resilience20LargeResilientStructV, ptr @fixedGlobal, i32 0, i32 1)
   %x_addr = struct_element_addr %addr : $*LargeResilientStruct, #LargeResilientStruct.x
   %x = load %x_addr : $*Int64
 
@@ -126,7 +126,7 @@ bb0:
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
 // CHECK:   [[FLAGS:%.*]] = load i32, ptr [[FLAGS_ADDR]]
 // CHECK:   [[ISNOTINLINE:%.*]] = and i32 [[FLAGS]], 131072
 // CHECK:   [[ISINLINE:%.*]] = icmp eq i32 [[ISNOTINLINE]], 0
@@ -138,7 +138,7 @@ bb0:
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[SIZE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+// CHECK:   [[SIZE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
 // CHECK:   [[SIZE:%.*]] = load [[INT]], ptr [[SIZE_ADDR]]
 // CHECK:   [[ALIGN:%.*]] = and {{.*}}, 255
 // CHECK:   [[PTR:%.*]] = call noalias ptr @swift_slowAlloc({{.*}} [[SIZE]], {{.*}} [[ALIGN]])
@@ -156,7 +156,7 @@ bb0:
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+// CHECK:   [[FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
 // CHECK:   [[FLAGS:%.*]] = load i32, ptr [[FLAGS_ADDR]]
 // CHECK:   [[ISNOTINLINE:%.*]] = and i32 [[FLAGS]], 131072
 // CHECK:   [[ISINLINE:%.*]] = icmp eq i32 [[ISNOTINLINE]], 0
diff --git a/test/IRGen/has_symbol_async.swift b/test/IRGen/has_symbol_async.swift
index 9cf2a8fde2c98..aa73c435b8087 100644
--- a/test/IRGen/has_symbol_async.swift
+++ b/test/IRGen/has_symbol_async.swift
@@ -34,7 +34,7 @@ public func testActor(_ a: A) {
   // CHECK: %{{[0-9]+}} = call i1 @"$s17has_symbol_helper1AC11asyncMethodyyYaFTwS"()
   if #_hasSymbol(a.asyncMethod) {}
 
-  // FIXME: Add support for actor isolated methods
+  // FIXME: Add support for actor-isolated methods
 }
 
 // --- A.init() ---
diff --git a/test/IRGen/indexing.sil b/test/IRGen/indexing.sil
index a908a84d15d9e..7196b8a065440 100644
--- a/test/IRGen/indexing.sil
+++ b/test/IRGen/indexing.sil
@@ -12,7 +12,7 @@ struct SameSizeStride { var x, y: Builtin.Int32 }
 // This type has unequal stride and size.
 struct DifferentSizeStride { var x: Builtin.Int32, y: Builtin.Int16 }
 
-// CHECK: define{{( protected)?}} {{.*}}void @same_size_stride(ptr noalias nocapture dereferenceable({{.*}}) %0, i64 %1) {{.*}} {
+// CHECK: define{{( protected)?}} {{.*}}void @same_size_stride(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, i64 %1) {{.*}} {
 // CHECK:   getelementptr inbounds %T8indexing14SameSizeStrideV, ptr %0, i64 %1
 sil @same_size_stride : $@convention(thin) (@in SameSizeStride, Builtin.Word) -> () {
 entry(%p : $*SameSizeStride, %i: $Builtin.Word):
@@ -20,7 +20,7 @@ entry(%p : $*SameSizeStride, %i: $Builtin.Word):
   return undef : $()
 }
 
-// CHECK:      define{{( protected)?}} {{.*}}void @different_size_stride(ptr noalias nocapture dereferenceable({{.*}}) %0, i64 %1) {{.*}} {
+// CHECK:      define{{( protected)?}} {{.*}}void @different_size_stride(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, i64 %1) {{.*}} {
 // CHECK:   %2 = mul nsw i64 %1, 8
 // CHECK-NEXT:   %3 = getelementptr inbounds i8, ptr %0, i64 %2
 sil @different_size_stride : $@convention(thin) (@in DifferentSizeStride, Builtin.Word) -> () {
@@ -29,7 +29,7 @@ entry(%p : $*DifferentSizeStride, %i: $Builtin.Word):
   return undef : $()
 }
 
-// CHECK:      define{{( protected)?}} {{.*}}void @zero_size(ptr noalias nocapture %0, i64 %1) {{.*}} {
+// CHECK:      define{{( protected)?}} {{.*}}void @zero_size(ptr noalias {{(nocapture|captures\(none\))}} %0, i64 %1) {{.*}} {
 // CHECK:   %2 = mul nsw i64 %1, 1
 // CHECK-NEXT:   %3 = getelementptr inbounds i8, ptr %0, i64 %2
 sil @zero_size : $@convention(thin) (@in (), Builtin.Word) -> () {
@@ -41,7 +41,7 @@ entry(%p : $*(), %i: $Builtin.Word):
 // CHECK:      define{{( protected)?}} {{.*}}void @dynamic_size(ptr noalias %0, i64 %1, ptr %T) {{.*}} {
 // CHECK:   [[T1:%.*]] = getelementptr inbounds ptr, ptr %T, i64 -1
 // CHECK-NEXT:   [[VWT:%T.valueWitnesses]] = load ptr, ptr [[T1]], align 8
-// CHECK:        [[STRIDE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 9
+// CHECK:        [[STRIDE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 9
 // CHECK:        [[STRIDE:%.*]] = load i64, ptr [[STRIDE_ADDR]]
 // CHECK-NEXT:   [[T0:%.*]] = mul nsw i64 %1, [[STRIDE]]
 // CHECK-NEXT:   getelementptr inbounds i8, ptr %0, i64 [[T0]]
diff --git a/test/IRGen/indirect_argument.sil b/test/IRGen/indirect_argument.sil
index bb521b9ba5907..0afca812fc2b9 100644
--- a/test/IRGen/indirect_argument.sil
+++ b/test/IRGen/indirect_argument.sil
@@ -15,9 +15,9 @@ struct HugeAlignment {
 }
 
 // TODO: could be the context param
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_method(ptr noalias nocapture swiftself dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_method(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{.*}}) %0)
 // CHECK-NOT:     alloca
-// CHECK:         call swiftcc void @huge_method(ptr noalias nocapture swiftself dereferenceable({{.*}}) %0)
+// CHECK:         call swiftcc void @huge_method(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{.*}}) %0)
 sil @huge_method : $@convention(method) (Huge) -> () {
 entry(%x : $Huge):
   %f = function_ref @huge_method : $@convention(method) (Huge) -> ()
@@ -25,9 +25,9 @@ entry(%x : $Huge):
   return %z : $()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_param(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_param(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 // CHECK-NOT:         alloca
-// CHECK:         call swiftcc void @huge_param(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK:         call swiftcc void @huge_param(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 sil @huge_param : $@convention(thin) (Huge) -> () {
 entry(%x : $Huge):
   %f = function_ref @huge_param : $@convention(thin) (Huge) -> ()
@@ -35,9 +35,9 @@ entry(%x : $Huge):
   return %z : $()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_alignment_param(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_alignment_param(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 // CHECK-NOT:     alloca
-// CHECK:         call swiftcc void @huge_alignment_param(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK:         call swiftcc void @huge_alignment_param(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 sil @huge_alignment_param : $@convention(thin) (HugeAlignment) -> () {
 entry(%x : $HugeAlignment):
   %f = function_ref @huge_alignment_param : $@convention(thin) (HugeAlignment) -> ()
@@ -45,9 +45,9 @@ entry(%x : $HugeAlignment):
   return %z : $()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_param_and_return(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_param_and_return(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1)
 // CHECK:         [[TMP_RET:%.*]] = alloca
-// CHECK:         call swiftcc void @huge_param_and_return(ptr noalias nocapture sret({{.*}}) [[TMP_RET]], ptr noalias nocapture dereferenceable({{.*}}) %1)
+// CHECK:         call swiftcc void @huge_param_and_return(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[TMP_RET]], ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1)
 sil @huge_param_and_return : $@convention(thin) (Huge) -> Huge {
 entry(%x : $Huge):
   %f = function_ref @huge_param_and_return : $@convention(thin) (Huge) -> Huge
@@ -55,9 +55,9 @@ entry(%x : $Huge):
   return %z : $Huge
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_param_and_indirect_return(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_param_and_indirect_return(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1)
 // CHECK-NOT:     alloca
-// CHECK:         call swiftcc void @huge_param_and_indirect_return(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1)
+// CHECK:         call swiftcc void @huge_param_and_indirect_return(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1)
 sil @huge_param_and_indirect_return : $@convention(thin) (Huge) -> @out Huge {
 entry(%o : $*Huge, %x : $Huge):
   %f = function_ref @huge_param_and_indirect_return : $@convention(thin) (Huge) -> @out Huge
@@ -65,16 +65,16 @@ entry(%o : $*Huge, %x : $Huge):
   return %z : $()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_partial_application(ptr noalias nocapture dereferenceable({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_partial_application(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1)
 // CHECK-NOT:     alloca
 // CHECK:         [[CLOSURE:%.*]] = call noalias ptr @swift_allocObject
-// CHECK:         call swiftcc {{.*}} @"$s24huge_partial_applicationTA{{(\.ptrauth)?}}"{{.*}}(ptr noalias nocapture dereferenceable({{.*}}) %0, ptr swiftself [[CLOSURE]])
-// CHECK:       define internal swiftcc void @"$s24huge_partial_applicationTA"(ptr noalias nocapture dereferenceable({{.*}}) %0, ptr swiftself %1)
+// CHECK:         call swiftcc {{.*}} @"$s24huge_partial_applicationTA{{(\.ptrauth)?}}"{{.*}}(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, ptr swiftself [[CLOSURE]])
+// CHECK:       define internal swiftcc void @"$s24huge_partial_applicationTA"(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, ptr swiftself %1)
 // CHECK-NOT:     alloca
-// CHECK:         [[GEP:%.*]] = getelementptr inbounds <{ %swift.refcounted, %T17indirect_argument4HugeV }>, ptr %1, i32 0, i32 1
+// CHECK:         [[GEP:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T17indirect_argument4HugeV }>, ptr %1, i32 0, i32 1
 // CHECK-NOT:     alloca
 // CHECK-NOT:     tail
-// CHECK:         call swiftcc void @huge_partial_application(ptr noalias nocapture dereferenceable({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) [[GEP]]
+// CHECK:         call swiftcc void @huge_partial_application(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) [[GEP]]
 // CHECK:         call void @swift_release(ptr %1)
 sil @huge_partial_application : $@convention(thin) (Huge, Huge) -> () {
 entry(%x : $Huge, %y : $Huge):
@@ -84,16 +84,16 @@ entry(%x : $Huge, %y : $Huge):
   return %z : $()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_partial_application_stret(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1, ptr noalias nocapture dereferenceable({{.*}}) %2)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @huge_partial_application_stret(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %2)
 // CHECK:         [[TMP_RET:%.*]] = alloca
 // CHECK:         [[CLOSURE:%.*]] = call noalias ptr @swift_allocObject
-// CHECK:         call swiftcc {{.*}} @"$s30huge_partial_application_stretTA{{(\.ptrauth)?}}"{{.*}}(ptr noalias nocapture sret({{.*}}) [[TMP_RET]], ptr noalias nocapture dereferenceable({{.*}}) %1, ptr swiftself [[CLOSURE]])
-// CHECK:       define internal swiftcc void @"$s30huge_partial_application_stretTA"(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1, ptr swiftself %2)
+// CHECK:         call swiftcc {{.*}} @"$s30huge_partial_application_stretTA{{(\.ptrauth)?}}"{{.*}}(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[TMP_RET]], ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1, ptr swiftself [[CLOSURE]])
+// CHECK:       define internal swiftcc void @"$s30huge_partial_application_stretTA"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1, ptr swiftself %2)
 // CHECK-NOT:     alloca
-// CHECK:         [[GEP:%.*]] = getelementptr inbounds <{ %swift.refcounted, %T17indirect_argument4HugeV }>, ptr %2, i32 0, i32 1
+// CHECK:         [[GEP:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T17indirect_argument4HugeV }>, ptr %2, i32 0, i32 1
 // CHECK-NOT:     alloca
 // CHECK-NOT:     tail
-// CHECK:         call swiftcc void @huge_partial_application_stret(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1, ptr noalias nocapture dereferenceable({{.*}}) [[GEP]])
+// CHECK:         call swiftcc void @huge_partial_application_stret(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) [[GEP]])
 // CHECK:         call void @swift_release(ptr %2)
 sil @huge_partial_application_stret : $@convention(thin) (Huge, Huge) -> Huge {
 entry(%x : $Huge, %y : $Huge):
diff --git a/test/IRGen/indirect_return.swift b/test/IRGen/indirect_return.swift
index 96b2a9bb02953..548b89349256e 100644
--- a/test/IRGen/indirect_return.swift
+++ b/test/IRGen/indirect_return.swift
@@ -14,12 +14,16 @@ protocol Number {}
 extension Int: Number {}
 
 // Make sure that the absence of the sret attribute matches.
-// CHECK: define hidden swiftcc void @"$s15indirect_return3fooSS_S2SAA6Number_pAaC_ptyF"(ptr noalias nocapture
+// CHECK: define hidden swiftcc void @"$s15indirect_return3fooSS_S2SAA6Number_pAaC_ptyF"(ptr noalias
+// CHECK-NOT: sret
+// CHECK-SAME: {
 func foo() -> (String, String, String, Number, Number) {
     return ("1", "2", "3", 42, 7)
 }
 // CHECK-LABEL: define{{.*}}testCall
 func testCall() {
-// CHECK: call swiftcc void @"$s15indirect_return3fooSS_S2SAA6Number_pAaC_ptyF"(ptr noalias nocapture %{{.*}}
+// CHECK: call swiftcc void @"$s15indirect_return3fooSS_S2SAA6Number_pAaC_ptyF"(ptr noalias
+// CHECK-NOT: sret
+// CHECK-SAME: ){{$}}
   print(foo())
 }
diff --git a/test/IRGen/inline_array_enum_tags.swift b/test/IRGen/inline_array_enum_tags.swift
new file mode 100644
index 0000000000000..21dc9abceeb5e
--- /dev/null
+++ b/test/IRGen/inline_array_enum_tags.swift
@@ -0,0 +1,40 @@
+// RUN: %target-swift-frontend -disable-availability-checking -O -emit-ir %s | %FileCheck %s
+
+public struct Foo {
+    let x: UInt64
+    let y: InlineArray<2, UInt64>
+}
+
+public struct Bar {
+    let x: UInt64
+    let y: [UInt64]
+}
+
+// CHECK: define {{.*}} i32 @"$s22inline_array_enum_tags3BazOwug"(ptr noalias{{( nocapture)?}} readonly{{( captures\(none\))?}} %value, ptr{{( nocapture)?}} readnone{{( captures\(none\))?}} %Baz)
+// CHECK:   [[TAG_ADDR:%.*]] = getelementptr inbounds{{.*}} i8, ptr %value, {{i64|i32}} 24
+// CHECK:   [[TAG_VAL:%.*]] = load i8, ptr [[TAG_ADDR]], align 8
+// CHECK:   [[TAG_EXT:%.*]] = zext i8 [[TAG_VAL]] to i32
+// CHECK:   ret i32 [[TAG_EXT]]
+// CHECK: }
+public enum Baz {
+    case foo(Foo)
+    case bar(Bar)
+}
+
+public struct Padded {
+    let x: UInt64
+    let y: InlineArray<2, (UInt16, UInt8)>
+}
+
+
+// CHECK: define {{.*}} i32 @"$s22inline_array_enum_tags17WithPaddedPayloadOwug"(ptr noalias{{( nocapture)?}} readonly{{( captures\(none\))?}} %value, ptr{{( nocapture)?}} readnone{{( captures\(none\))?}} %WithPaddedPayload)
+// CHECK: entry:
+// CHECK:   [[ADDR:%.*]] = getelementptr inbounds{{.*}} i8, ptr %value, {{i64|i32}} 8
+// CHECK:   [[VAL:%.*]] = load {{i64|i32}}, ptr [[ADDR]], align 8
+// CHECK:   [[TAG:%.*]] = lshr i32 {{%.*}}, 31
+// CHECK:   ret i32 [[TAG]]
+// CHECK: }
+public enum WithPaddedPayload {
+    case a(Padded)
+    case b(Padded)
+}
diff --git a/test/IRGen/inout_noalias.sil b/test/IRGen/inout_noalias.sil
index 6a3c4fe86bce6..41baac79525c1 100644
--- a/test/IRGen/inout_noalias.sil
+++ b/test/IRGen/inout_noalias.sil
@@ -2,7 +2,7 @@
 
 import Swift
 
-// CHECK: define{{.*}}swiftcc void @takeInoutAliasable(ptr nocapture dereferenceable({{[0-9]+}}) %0, ptr %T)
+// CHECK: define{{.*}}swiftcc void @takeInoutAliasable(ptr {{(nocapture|captures\(none\))}} dereferenceable({{[0-9]+}}) %0, ptr %T)
 sil @takeInoutAliasable : $<T> (@inout_aliasable UnsafePointer<T>) -> () {
 entry(%ptr : $*UnsafePointer<T>):
   %retval = tuple ()
diff --git a/test/IRGen/integer-comparison.swift b/test/IRGen/integer-comparison.swift
index ac7d4677ce13a..d5052c461cf4c 100644
--- a/test/IRGen/integer-comparison.swift
+++ b/test/IRGen/integer-comparison.swift
@@ -4,11 +4,11 @@
 func f(_ x: Int, _ y: UInt32) -> Bool { x < y }
 // CHECK-LABEL: define {{.*}} @"$s4main1fySbSi_s6UInt32VtF"(i64 %0, i32 %1)
 // CHECK: %2 = zext i32 %1 to i64
-// CHECK-NEXT: %3 = icmp sgt i64 %2, %0
+// CHECK-NEXT: %3 = icmp slt i64 %0, %2
 // CHECK-NEXT: ret i1 %3
 
 func g(_ x: UInt32, _ y: Int) -> Bool { x < y }
 // CHECK-LABEL: define {{.*}} @"$s4main1gySbs6UInt32V_SitF"(i32 %0, i64 %1)
 // CHECK: %2 = zext i32 %0 to i64
-// CHECK-NEXT: %3 = icmp slt i64 %2, %1
+// CHECK-NEXT: %3 = icmp sgt i64 %1, %2
 // CHECK-NEXT: ret i1 %3
diff --git a/test/IRGen/isolated_any.sil b/test/IRGen/isolated_any.sil
index 5c688a2ab94cf..cb4096d070d2b 100644
--- a/test/IRGen/isolated_any.sil
+++ b/test/IRGen/isolated_any.sil
@@ -25,12 +25,12 @@ entry(%actor: $Optional<any Actor>, %int: $Int):
 //   ptr: int capture
 // CHECK-64: [[BOX:%.*]] = call noalias ptr @swift_allocObject(ptr {{.*}}, [[INT]] 48, [[INT]] 7)
 // CHECK-32: [[BOX:%.*]] = call noalias ptr @swift_allocObject(ptr {{.*}}, [[INT]] 24, [[INT]] 3)
-// CHECK-NEXT: [[ISO_ADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted, %TScA_pSg, [{{4|8}} x i8], %TSi }>, ptr [[BOX]], i32 0, i32 1
-// CHECK-NEXT: [[ISO_REF_ADDR:%.*]] = getelementptr inbounds { [[INT]], [[INT]] }, ptr [[ISO_ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[ISO_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TScA_pSg, [{{4|8}} x i8], %TSi }>, ptr [[BOX]], i32 0, i32 1
+// CHECK-NEXT: [[ISO_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { [[INT]], [[INT]] }, ptr [[ISO_ADDR]], i32 0, i32 0
 // CHECK-NEXT: store [[INT]] %0, ptr [[ISO_REF_ADDR]], align
-// CHECK-NEXT: [[ISO_WT_ADDR:%.*]] = getelementptr inbounds { [[INT]], [[INT]] }, ptr [[ISO_ADDR]], i32 0, i32 1
+// CHECK-NEXT: [[ISO_WT_ADDR:%.*]] = getelementptr inbounds{{.*}} { [[INT]], [[INT]] }, ptr [[ISO_ADDR]], i32 0, i32 1
 // CHECK-NEXT: store [[INT]] %1, ptr [[ISO_WT_ADDR]], align
-// CHECK-NEXT: [[T_ADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted, %TScA_pSg, [{{4|8}} x i8], %TSi }>, ptr [[BOX]], i32 0, i32 2
+// CHECK-NEXT: [[T_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TScA_pSg, [{{4|8}} x i8], %TSi }>, ptr [[BOX]], i32 0, i32 2
 // CHECK-NEXT: store ptr %T, ptr [[T_ADDR]], align
 // CHECK:      [[RESULT:%.*]] = insertvalue { ptr, ptr } { ptr @"$s7closureTA{{(\.ptrauth.*)?}}", ptr undef }, ptr [[BOX]], 1
 // CHECK-NEXT: ret { ptr, ptr } [[RESULT]]
@@ -40,13 +40,13 @@ entry(%fn : $@callee_guaranteed @isolated(any) () -> ()):
   %actor = function_extract_isolation %fn : $@callee_guaranteed @isolated(any) () -> ()
   return %actor : $Optional<any Actor>
 }
-// CHECK-LABEL-64: define{{( dllexport)?}}{{( protected)?}} swiftcc { i64, i64 } @extract_closure_isolation
-// CHECK-LABEL-32: define{{( dllexport)?}}{{( protected)?}} swiftcc { i32, i32 } @extract_closure_isolation
+// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { i64, i64 } @extract_closure_isolation
+// CHECK-32-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { i32, i32 } @extract_closure_isolation
 // CHECK-64:   [[ISO_ADDR:%.*]] = getelementptr inbounds i8, ptr %1, i32 16
 // CHECK-32:   [[ISO_ADDR:%.*]] = getelementptr inbounds i8, ptr %1, i32 8
-// CHECK-NEXT: [[ISO_REF_ADDR:%.*]] = getelementptr inbounds { [[INT]], [[INT]] }, ptr [[ISO_ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[ISO_REF_ADDR:%.*]] = getelementptr inbounds{{.*}} { [[INT]], [[INT]] }, ptr [[ISO_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[ISO_REF:%.*]] = load [[INT]], ptr [[ISO_REF_ADDR]], align
-// CHECK-NEXT: [[ISO_WT_ADDR:%.*]] = getelementptr inbounds { [[INT]], [[INT]] }, ptr [[ISO_ADDR]], i32 0, i32 1
+// CHECK-NEXT: [[ISO_WT_ADDR:%.*]] = getelementptr inbounds{{.*}} { [[INT]], [[INT]] }, ptr [[ISO_ADDR]], i32 0, i32 1
 // CHECK-NEXT: [[ISO_WT:%.*]] = load [[INT]], ptr [[ISO_WT_ADDR]], align
 // CHECK-NEXT: [[T0:%.*]] = insertvalue { [[INT]], [[INT]] } undef, [[INT]] [[ISO_REF]], 0
 // CHECK-NEXT: [[T1:%.*]] = insertvalue { [[INT]], [[INT]] } [[T0]], [[INT]] [[ISO_WT]], 1
diff --git a/test/IRGen/isolated_conformance.swift b/test/IRGen/isolated_conformance.swift
index 6240933188ed3..6900cf905736d 100644
--- a/test/IRGen/isolated_conformance.swift
+++ b/test/IRGen/isolated_conformance.swift
@@ -1,8 +1,7 @@
-// RUN: %target-swift-frontend -primary-file %s -emit-ir -swift-version 6 -enable-experimental-feature IsolatedConformances | %FileCheck %s -DINT=i%target-ptrsize
+// RUN: %target-swift-frontend -primary-file %s -emit-ir -swift-version 6 | %FileCheck %s -DINT=i%target-ptrsize
 
 // REQUIRES: PTRSIZE=64
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_IsolatedConformances
 // UNSUPPORTED: CPU=arm64e
 
 protocol P {
diff --git a/test/IRGen/keypath_accessor.sil b/test/IRGen/keypath_accessor.sil
index c0483963befa0..2520396ece12d 100644
--- a/test/IRGen/keypath_accessor.sil
+++ b/test/IRGen/keypath_accessor.sil
@@ -10,7 +10,7 @@ public struct Blah {
 }
 
 // CHECK: define{{.*}} swiftcc void @"$simple_getter"(
-// CHECK-SAME: ptr{{.*}} sret(%TSi) %0,
+// CHECK-SAME: ptr{{.*}} sret(%TSi){{( captures\(none\))?}} %0,
 // CHECK-SAME: ptr{{.*}} %1,
 // CHECK-SAME: ptr{{.*}} %2, [[INT]] %3)
 sil @$simple_getter : $@convention(keypath_accessor_getter) (@in_guaranteed Blah) -> @out Int {
diff --git a/test/IRGen/large_argument_c.sil b/test/IRGen/large_argument_c.sil
index 1141d8714d73b..656d480899d07 100644
--- a/test/IRGen/large_argument_c.sil
+++ b/test/IRGen/large_argument_c.sil
@@ -21,7 +21,7 @@ sil @pass_and_return : $@convention(c) (large_thing, large_thing) -> large_thing
 
 // CHECK: define{{.*}} swiftcc void @test(ptr {{.*}} dereferenceable(256) %0)
 // CHECK:   [[TMP:%.*]] = alloca %TSo11large_thinga
-// CHECK:   [[PROJ_ADDR:%.*]] = getelementptr inbounds i8, ptr %0, i64 128
+// CHECK:   [[PROJ_ADDR:%.*]] = getelementptr inbounds{{.*}} i8, ptr %0, i64 128
 // CHECK:   [[VAL:%.*]] = load i64, ptr %.sroa.3.0..sroa_idx
 // CHECK:   store i64 [[VAL]], ptr [[TMP]]
 sil @test : $@convention(thin) (@in ContainingLargeThing) -> () {
diff --git a/test/IRGen/large_argument_result_c.swift b/test/IRGen/large_argument_result_c.swift
index c90042fbd4b66..fa05e2f14a025 100644
--- a/test/IRGen/large_argument_result_c.swift
+++ b/test/IRGen/large_argument_result_c.swift
@@ -16,7 +16,7 @@
 // CHECK:  call void @pass_and_return(ptr {{.*}} [[CALL_ALLOCA]], ptr nonnull [[TMP_ALLOCA]], ptr nonnull [[TMP_ALLOCA2]])
 // CHECK:  call {{.*}} @swift_allocObject
 // CHECK:  [[BOX:%.*]] = call noalias ptr @swift_allocObject(
-// CHECK:  [[ADDR_IN_BOX:%.*]] = getelementptr inbounds i8, ptr [[BOX]], i64 16
+// CHECK:  [[ADDR_IN_BOX:%.*]] = getelementptr inbounds{{.*}} i8, ptr [[BOX]], i64 16
 // CHECK:  call void @llvm.memcpy.p0.p0.i64(ptr {{.*}} [[ADDR_IN_BOX]], ptr {{.*}} [[CALL_ALLOCA]], i64 128, i1 false)
 // CHECK:  call void @llvm.lifetime.end.p0(i64 128, ptr nonnull [[CALL_ALLOCA]])
 public func runTest(_ l : large_thing) {
diff --git a/test/IRGen/large_argument_result_c_x86_64.swift b/test/IRGen/large_argument_result_c_x86_64.swift
index be69a0c5e09af..831837ba726cf 100644
--- a/test/IRGen/large_argument_result_c_x86_64.swift
+++ b/test/IRGen/large_argument_result_c_x86_64.swift
@@ -15,7 +15,7 @@
 // CHECK:  call void @pass_and_return(ptr {{.*}} [[CALL_ALLOCA]], ptr nonnull byval{{.*}} %0, ptr nonnull byval{{.*}} %0)
 // CHECK:  call {{.*}} @swift_allocObject
 // CHECK:  [[BOX:%.*]] = {{.*}}call noalias ptr @swift_allocObject(
-// CHECK:  [[ADDR_IN_BOX:%.*]] = getelementptr inbounds i8, ptr [[BOX]], i64 16
+// CHECK:  [[ADDR_IN_BOX:%.*]] = getelementptr inbounds{{.*}} i8, ptr [[BOX]], i64 16
 // CHECK:  call void @llvm.memcpy.p0.p0.i64(ptr {{.*}} [[ADDR_IN_BOX]], ptr {{.*}} [[CALL_ALLOCA]], i64 128, i1 false)
 // CHECK:  call void @llvm.lifetime.end.p0(i64 128, ptr nonnull [[CALL_ALLOCA]])
 public func runTest(_ l : large_thing) {
diff --git a/test/IRGen/lazy_globals.swift b/test/IRGen/lazy_globals.swift
index 457e33fbfaf81..ea27c21b1d6d5 100644
--- a/test/IRGen/lazy_globals.swift
+++ b/test/IRGen/lazy_globals.swift
@@ -1,11 +1,11 @@
 // RUN: %target-swift-frontend -parse-as-library -emit-ir -primary-file %s | %FileCheck %s
 
-// REQUIRES: CPU=x86_64
+// REQUIRES: CPU=x86_64 || CPU=arm64
 
-// CHECK: @"[[T:.*]]Wz" = internal global i64 0, align 8
 // CHECK: @"$s12lazy_globals1xSivp" = hidden global %TSi zeroinitializer, align 8
 // CHECK: @"$s12lazy_globals1ySivp" = hidden global %TSi zeroinitializer, align 8
 // CHECK: @"$s12lazy_globals1zSivp" = hidden global %TSi zeroinitializer, align 8
+// CHECK: @"[[T:.*]]Wz" = internal global i64 0, align 8
 
 // CHECK: define internal void @"[[T]]WZ"(ptr %0) {{.*}} {
 // CHECK: entry:
@@ -34,9 +34,8 @@ var (x, y, z) = (1, 2, 3)
 // CHECK: define hidden swiftcc i64 @"$s12lazy_globals4getXSiyF"() {{.*}} {
 // CHECK: entry:
 // CHECK:   %0 = call swiftcc ptr @"$s12lazy_globals1xSivau"()
-// CHECK:   %._value = getelementptr inbounds %TSi, ptr %0, i32 0, i32 0
+// CHECK:   %._value = getelementptr inbounds{{.*}} %TSi, ptr %0, i32 0, i32 0
 // CHECK:   [[V:%.*]] = load i64, ptr %._value, align 8
 // CHECK:   ret i64 [[V]]
 // CHECK: }
 func getX() -> Int { return x }
-
diff --git a/test/IRGen/lazy_multi_file.swift b/test/IRGen/lazy_multi_file.swift
index 7e53cbd4d6833..c2c382f4aea8d 100644
--- a/test/IRGen/lazy_multi_file.swift
+++ b/test/IRGen/lazy_multi_file.swift
@@ -14,9 +14,9 @@ class Subclass : LazyContainerClass {
   // an indirect return value. When it shrinks back, remove the optional
   // indirect out.
   //
-  // CHECK-LABEL: @"$s15lazy_multi_file8SubclassC6getStrSSyF"({{(ptr noalias nocapture sret, )?}}ptr swiftself %0) {{.*}} {
+  // CHECK-LABEL: @"$s15lazy_multi_file8SubclassC6getStrSSyF"({{(ptr noalias( nocapture)? sret( captures\(none\))?, )?}}ptr swiftself %0) {{.*}} {
   func getStr() -> String {
-    // CHECK: = getelementptr inbounds %T15lazy_multi_file8SubclassC, ptr %0, i32 0, i32 3
+    // CHECK: = getelementptr inbounds{{.*}} %T15lazy_multi_file8SubclassC, ptr %0, i32 0, i32 3
     return str
   }
 }
diff --git a/test/IRGen/lifetime.sil b/test/IRGen/lifetime.sil
index e4909f3356dd9..c2a6b6cbdc7f3 100644
--- a/test/IRGen/lifetime.sil
+++ b/test/IRGen/lifetime.sil
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -disable-debugger-shadow-copies -gnone -emit-ir %s | %FileCheck --check-prefix=CHECK --check-prefix=CHECK-%target-cpu %s -DINT=i%target-ptrsize
+// RUN: %target-swift-frontend -disable-debugger-shadow-copies -Xllvm -sil-disable-pass=mandatory-temp-rvalue-elimination -gnone -emit-ir %s | %FileCheck --check-prefix=CHECK --check-prefix=CHECK-%target-cpu %s -DINT=i%target-ptrsize
 
 sil_stage canonical
 
@@ -21,7 +21,7 @@ bb0(%x : $*T):
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK-NEXT: [[SIZE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+// CHECK-NEXT: [[SIZE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
 // CHECK-NEXT: [[SIZE:%.*]] = load [[INT]], ptr [[SIZE_ADDR]]
 // CHECK-NEXT: [[Y_ALLOCA:%.*]] = alloca i8, {{.*}} [[SIZE]], align 16
 // CHECK-NEXT: call void @llvm.lifetime.start.p0({{(i32|i64)}} -1, ptr [[Y_ALLOCA]])
@@ -61,7 +61,7 @@ bb0(%x : $*T):
 // CHECK-arm64e-NEXT: ptrtoint ptr [[VWT_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
-// CHECK-NEXT: [[SIZE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+// CHECK-NEXT: [[SIZE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
 // CHECK-NEXT: [[SIZE:%.*]] = load [[INT]], ptr [[SIZE_ADDR]]
 // CHECK-NEXT: [[Y_ALLOCA:%.*]] = alloca i8, {{.*}} [[SIZE]], align 16
 // CHECK-NEXT: call void @llvm.lifetime.start.p0({{(i32|i64)}} -1, ptr [[Y_ALLOCA]])
@@ -99,7 +99,7 @@ bb0(%x : $*Builtin.Int64):
   %0 = tuple ()
   return %0 : $()
 }
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @fixed_size(ptr noalias nocapture dereferenceable(8) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @fixed_size(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(8) %0)
 // CHECK:         [[XBUF:%.*]] = alloca i64
 // CHECK-NEXT:    call void @llvm.lifetime.start.p0({{(i32|i64)}} 8, ptr [[XBUF]])
 // CHECK-NEXT:    load
diff --git a/test/IRGen/loadable_by_address.swift b/test/IRGen/loadable_by_address.swift
index c5804b9235f55..4de89f870b350 100644
--- a/test/IRGen/loadable_by_address.swift
+++ b/test/IRGen/loadable_by_address.swift
@@ -30,3 +30,30 @@ public class Test {
     }
   }
 }
+
+// So did this test case.
+enum E {
+  case a
+}
+
+protocol P {
+  associatedtype A
+  typealias S = C<A>.S
+
+  var v: E { get set }
+
+  var v2: (t: Int, i: S)? { get set }
+}
+
+class C<A> {
+  struct S { }
+
+  init(_: ClosedRange<Double>) { }
+}
+
+class C2<T>: P {
+  typealias A = T
+  var v: E = .a
+
+  var v2: (t: Int, i: S)?
+}
diff --git a/test/IRGen/loadable_by_address_address_assignment.swift b/test/IRGen/loadable_by_address_address_assignment.swift
index 1db3751bdb9ce..d31058ba40663 100644
--- a/test/IRGen/loadable_by_address_address_assignment.swift
+++ b/test/IRGen/loadable_by_address_address_assignment.swift
@@ -3,8 +3,6 @@
 // REQUIRES: swift_stdlib_no_asserts,optimized_stdlib
 
 // wasm currently disables aggressive reg2mem
-// UNSUPPORTED: wasm
-// UNSUPPORTED: OS=wasi
 // UNSUPPORTED: CPU=wasm32
 
 public struct LargeThing {
diff --git a/test/IRGen/loadable_by_address_reg2mem.sil b/test/IRGen/loadable_by_address_reg2mem.sil
index dd69690249bf4..a28b4ffc768ba 100644
--- a/test/IRGen/loadable_by_address_reg2mem.sil
+++ b/test/IRGen/loadable_by_address_reg2mem.sil
@@ -1,8 +1,6 @@
 // RUN: %target-swift-frontend %s  -Xllvm -sil-print-types -Xllvm -sil-print-after=loadable-address -import-objc-header %S/Inputs/large_c.h -c -o %t/t.o 2>&1 | %FileCheck %s
 
 // wasm currently disables aggressive reg2mem
-// UNSUPPORTED: wasm
-// UNSUPPORTED: OS=wasi
 // UNSUPPORTED: CPU=wasm32
 // REQUIRES: PTRSIZE=64
 
@@ -68,15 +66,12 @@ struct Small {
 // CHECK: bb0:
 // CHECK:   %0 = alloc_stack $Optional<X>
 // CHECK:   %1 = alloc_stack $X
-// CHECK:   %2 = alloc_stack $X
-// CHECK:   %3 = alloc_stack $Optional<X>
-// CHECK:   copy_addr [take] %2 to [init] %1 : $*X
-// CHECK:   %5 = init_enum_data_addr %0 : $*Optional<X>, #Optional.some!enumelt
-// CHECK:   copy_addr [take] %1 to [init] %5 : $*X
+// CHECK:   %2 = alloc_stack $Optional<X>
+// CHECK:   %3 = init_enum_data_addr %0 : $*Optional<X>, #Optional.some!enumelt
+// CHECK:   copy_addr [take] %1 to [init] %3 : $*X
 // CHECK:   inject_enum_addr %0 : $*Optional<X>, #Optional.some!enumelt
-// CHECK:   copy_addr [take] %0 to [init] %3 : $*Optional<X>
-// CHECK:   dealloc_stack %3 : $*Optional<X>
-// CHECK:   dealloc_stack %2 : $*X
+// CHECK:   copy_addr [take] %0 to [init] %2 : $*Optional<X>
+// CHECK:   dealloc_stack %2 : $*Optional<X>
 // CHECK:   dealloc_stack %1 : $*X
 // CHECK:   dealloc_stack %0 : $*Optional<X>
 // CHECK: } // end sil function 'test1'
@@ -94,17 +89,21 @@ bb0:
   return %t : $()
 }
 
+sil @useX : $@convention(thin) (X) -> ()
+
 // CHECK: sil @test2 : $@convention(thin) () -> () {
 // CHECK: bb0:
 // CHECK:   %0 = alloc_stack $Optional<X>
-// CHECK:   %1 = alloc_stack $Optional<X>
+// CHECK:   %1 = alloc_stack $X
 // CHECK:   %2 = alloc_stack $Optional<X>
-// CHECK:   copy_addr [take] %2 to [init] %1 : $*Optional<X>
-// CHECK:   copy_addr [take] %1 to [init] %0 : $*Optional<X>
-// CHECK:   switch_enum_addr %0 : $*Optional<X>, case #Optional.some!enumelt: bb1, case #Optional.none!enumelt: bb2
+// CHECK:   copy_addr [take] %2 to [init] %0 : $*Optional<X>
+// CHECK:   switch_enum_addr %2 : $*Optional<X>, case #Optional.some!enumelt: bb1, case #Optional.none!enumelt: bb2
 
 // CHECK: bb1:
-// CHECK:   %6 = unchecked_take_enum_data_addr %0 : $*Optional<X>, #Optional.some!enumelt
+// CHECK:   %5 = unchecked_take_enum_data_addr %0 : $*Optional<X>, #Optional.some!enumelt
+// CHECK:   copy_addr [take] %5 to [init] %1 : $*X
+// CHECK:   %7 = function_ref @useX : $@convention(thin) (@in_guaranteed X) -> ()
+// CHECK:   %8 = apply %7(%1) : $@convention(thin) (@in_guaranteed X) -> ()
 // CHECK:   br bb3
 
 // CHECK: bb2:
@@ -112,7 +111,7 @@ bb0:
 
 // CHECK: bb3:
 // CHECK:   dealloc_stack %2 : $*Optional<X>
-// CHECK:   dealloc_stack %1 : $*Optional<X>
+// CHECK:   dealloc_stack %1 : $*X
 // CHECK:   dealloc_stack %0 : $*Optional<X>
 // CHECK: } // end sil function 'test2'
 
@@ -123,6 +122,8 @@ bb0:
   switch_enum %2 : $Optional<X>, case #Optional.some!enumelt: bb1, case #Optional.none!enumelt: bb2
 
 bb1(%3: $X):
+  %f = function_ref @useX : $@convention(thin) (X) -> ()
+  apply %f(%3) : $@convention(thin) (X) -> ()
   br bb3
 
 bb2:
@@ -186,11 +187,9 @@ bb0:
 
 // CHECK: sil @test5 : $@convention(thin) (@in (X, X)) -> () {
 // CHECK: bb0(%0 : $*(X, X)):
-// CHECK:   %1 = alloc_stack $(X, X)
-// CHECK:   %2 = alloc_stack $X
-// CHECK:   copy_addr [take] %0 to [init] %1 : $*(X, X)
-// CHECK:   %4 = tuple_element_addr %1 : $*(X, X), 1
-// CHECK:   copy_addr [take] %4 to [init] %2 : $*X
+// CHECK:   %1 = alloc_stack $X
+// CHECK:   %2 = tuple_element_addr %0 : $*(X, X), 1
+// CHECK:   copy_addr [take] %2 to [init] %1 : $*X
 // CHECK: } // end sil function 'test5'
 
 sil @test5 : $@convention(thin) (@in (X, X)) -> () {
@@ -233,11 +232,9 @@ bb0:
 
 // CHECK: sil @test7 : $@convention(thin) (@in Y) -> () {
 // CHECK: bb0(%0 : $*Y):
-// CHECK:   %1 = alloc_stack $Y
-// CHECK:   %2 = alloc_stack $X
-// CHECK:   copy_addr [take] %0 to [init] %1 : $*Y
-// CHECK:   %4 = struct_element_addr %1 : $*Y, #Y.y1
-// CHECK:   copy_addr [take] %4 to [init] %2 : $*X
+// CHECK:  %1 = alloc_stack $X
+// CHECK:  %2 = struct_element_addr %0 : $*Y, #Y.y1
+// CHECK:  copy_addr [take] %2 to [init] %1 : $*X
 // CHECK: } // end sil function 'test7'
 
 sil @test7 : $@convention(thin) (@in Y) -> () {
@@ -341,8 +338,8 @@ bb0:
 }
 
 // CHECK: sil @test13
-// CHECK:  [[ADDR:%.*]] = unchecked_addr_cast %1 : $*X to $*Y
-// CHECK:  copy_addr [take] [[ADDR]] to [init] %2 : $*Y
+// CHECK:  [[ADDR:%.*]] = unchecked_addr_cast %2 : $*X to $*Y
+// CHECK:  copy_addr [take] [[ADDR]] to [init] %1 : $*Y
 // CHECK: } // end sil function 'test13'
 sil @test13 : $@convention(thin) (@in X) -> () {
 bb0(%0 : $*X):
@@ -425,3 +422,44 @@ bb0(%0 : $member_id_t):
   %13 = tuple ()
   return %13 : $()
 }
+
+struct Z {
+  var r: String
+  var p: X
+}
+
+// CHECK: sil @test17 : $@convention(thin) (@owned String) -> () {
+// CHECK: bb0(%0 : $String):
+// CHECK:   [[T0:%.*]] = alloc_stack $String
+// CHECK:   store %0 to [[T0]] : $*String
+// CHECK:   [[T1:%.*]] = unchecked_addr_cast [[T0]] : $*String to $*Z
+// CHECK:   release_value_addr [[T1]] : $*Z
+
+sil @test17: $@convention(thin) (@owned String) -> () {
+bb0(%0 : $String):
+  %1 = unchecked_bitwise_cast %0 : $String to $Z
+  release_value %1 : $Z
+  %13 = tuple ()
+  return %13 : $()
+}
+
+sil_global private @global : $Optional<X>
+
+sil @test18: $@convention(thin) () -> () {
+bb0:
+  %0 = global_addr @global : $*Optional<X>
+  %1 = begin_access [modify] [static] [no_nested_conflict] %0
+  %2 = load %1
+  switch_enum %2, case #Optional.some!enumelt: bb2, case #Optional.none!enumelt: bb1
+
+bb1:
+  %4 = integer_literal $Builtin.Int1, -1
+  cond_fail %4, "Unexpectedly found nil while unwrapping an Optional value"
+  unreachable
+
+bb2(%7 : $X):
+  %8 = unchecked_take_enum_data_addr %1, #Optional.some!enumelt
+  end_access %1
+  %13 = tuple ()
+  return %13 : $()
+}
diff --git a/test/IRGen/loadable_by_address_reg2mem_fixed_array.sil b/test/IRGen/loadable_by_address_reg2mem_fixed_array.sil
index b7b1bb7e00da7..5632c93ddbd2f 100644
--- a/test/IRGen/loadable_by_address_reg2mem_fixed_array.sil
+++ b/test/IRGen/loadable_by_address_reg2mem_fixed_array.sil
@@ -5,8 +5,6 @@
 // REQUIRES: swift_feature_BuiltinModule
 
 // wasm currently disables aggressive reg2mem
-// UNSUPPORTED: wasm
-// UNSUPPORTED: OS=wasi
 // UNSUPPORTED: CPU=wasm32
 
 import Builtin
diff --git a/test/IRGen/lto_autolink.swift b/test/IRGen/lto_autolink.swift
index 9a9ba4b576e23..6711bf4e3a8b4 100644
--- a/test/IRGen/lto_autolink.swift
+++ b/test/IRGen/lto_autolink.swift
@@ -19,8 +19,8 @@ import empty
 
 
 // RUN: %target-swift-frontend -target %target-cpu-apple-macosx10.15 -emit-module -parse-stdlib -o %t -module-name empty -module-link-name empty %S/../Inputs/empty.swift
-// RUN: %target-swift-emit-ir -target %target-cpu-apple-macosx10.15 -lto=llvm-full -parse-stdlib -I %t -I %S/Inputs -DTEST_CLANG_OPTIONS_MERGE %s | %FileCheck %s --check-prefix CHECK-MACHO-MERGE
-// RUN: %target-swift-emit-ir -target %target-cpu-apple-macosx10.15 -lto=llvm-thin -parse-stdlib -I %t -I %S/Inputs -DTEST_CLANG_OPTIONS_MERGE %s | %FileCheck %s --check-prefix CHECK-MACHO-MERGE
+// RUN: %target-swift-emit-ir -target %target-cpu-apple-macosx10.15 -lto=llvm-full -parse-stdlib -nostdimport -I %t -I %S/Inputs -DTEST_CLANG_OPTIONS_MERGE %s | %FileCheck %s --check-prefix CHECK-MACHO-MERGE
+// RUN: %target-swift-emit-ir -target %target-cpu-apple-macosx10.15 -lto=llvm-thin -parse-stdlib -nostdimport -I %t -I %S/Inputs -DTEST_CLANG_OPTIONS_MERGE %s | %FileCheck %s --check-prefix CHECK-MACHO-MERGE
 
 // CHECK-MACHO-MERGE-DAG: !llvm.linker.options = !{
 // CHECK-MACHO-MERGE-DAG: !{{[0-9]+}} = !{!"-lempty"}
@@ -28,8 +28,8 @@ import empty
 
 
 // RUN: %target-swift-frontend -target %target-cpu-unknown-linux-gnu -emit-module -parse-stdlib -o %t -module-name empty -module-link-name empty %S/../Inputs/empty.swift
-// RUN: %target-swift-emit-ir -target %target-cpu-unknown-linux-gnu -lto=llvm-full -parse-stdlib -I %t -I %S/Inputs -DTEST_CLANG_OPTIONS_MERGE %s | %FileCheck %s --check-prefix CHECK-ELF-MERGE
-// RUN: %target-swift-emit-ir -target %target-cpu-unknown-linux-gnu -lto=llvm-thin -parse-stdlib -I %t -I %S/Inputs -DTEST_CLANG_OPTIONS_MERGE %s | %FileCheck %s --check-prefix CHECK-ELF-MERGE
+// RUN: %target-swift-emit-ir -target %target-cpu-unknown-linux-gnu -lto=llvm-full -parse-stdlib -nostdimport -I %t -I %S/Inputs -DTEST_CLANG_OPTIONS_MERGE %s | %FileCheck %s --check-prefix CHECK-ELF-MERGE
+// RUN: %target-swift-emit-ir -target %target-cpu-unknown-linux-gnu -lto=llvm-thin -parse-stdlib -nostdimport -I %t -I %S/Inputs -DTEST_CLANG_OPTIONS_MERGE %s | %FileCheck %s --check-prefix CHECK-ELF-MERGE
 
 // CHECK-ELF-MERGE-DAG: !llvm.dependent-libraries = !{
 // CHECK-ELF-MERGE-DAG: !{{[0-9]+}} = !{!"empty"}
@@ -43,8 +43,5 @@ import AutolinkElfCPragma
 import AutolinkModuleMapLink
 #endif
 
-// UNSUPPORTED: OS=macosx && CPU=arm64
-// UNSUPPORTED: OS=ios && CPU=arm64e
 // UNSUPPORTED: OS=watchos && (CPU=arm64_32 || CPU=armv7k)
-// UNSUPPORTED: OS=linux-gnu && CPU=aarch64
 // UNSUPPORTED: CPU=wasm32
diff --git a/test/IRGen/mixed_mode_class_with_unimportable_fields.swift b/test/IRGen/mixed_mode_class_with_unimportable_fields.swift
index 9bd7f2bd40a94..8b64e7cba224f 100644
--- a/test/IRGen/mixed_mode_class_with_unimportable_fields.swift
+++ b/test/IRGen/mixed_mode_class_with_unimportable_fields.swift
@@ -36,9 +36,9 @@ public func accessFinalFields(of holder: ButtHolder) -> (Any, Any) {
 
   // ButtHolder.y is correctly imported in Swift 5 mode, so we can use fixed offsets.
 
-  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds %T14UsingObjCStuff10ButtHolderC, ptr %2, i32 0, i32 1
+  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds{{.*}} %T14UsingObjCStuff10ButtHolderC, ptr %2, i32 0, i32 1
 
-  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds %T14UsingObjCStuff10ButtHolderC, ptr %2, i32 0, i32 3
+  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds{{.*}} %T14UsingObjCStuff10ButtHolderC, ptr %2, i32 0, i32 3
 
   return (holder.x, holder.z)
 }
@@ -63,11 +63,11 @@ public func accessFinalFields(ofSub holder: SubButtHolder) -> (Any, Any, Any) {
   
   // ButtHolder.y is correctly imported in Swift 5 mode, so we can use fixed offsets.
 
-  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds %T14UsingObjCStuff10ButtHolderC, ptr %3, i32 0, i32 1
+  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds{{.*}} %T14UsingObjCStuff10ButtHolderC, ptr %3, i32 0, i32 1
 
-  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds %T14UsingObjCStuff10ButtHolderC, ptr %3, i32 0, i32 3
+  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds{{.*}} %T14UsingObjCStuff10ButtHolderC, ptr %3, i32 0, i32 3
 
-  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds %T4main13SubButtHolderC, ptr %3, i32 0, i32 4
+  // CHECK-V5: [[OFFSET:%.*]] = getelementptr inbounds{{.*}} %T4main13SubButtHolderC, ptr %3, i32 0, i32 4
 
   return (holder.x, holder.z, holder.w)
 }
diff --git a/test/IRGen/moveonly_deinit.sil b/test/IRGen/moveonly_deinit.sil
index 8b677cf46f89e..bd73a2f3727dd 100644
--- a/test/IRGen/moveonly_deinit.sil
+++ b/test/IRGen/moveonly_deinit.sil
@@ -183,8 +183,6 @@ entry(%b : $*MOStruct):
 
 // CHECK-LABEL: define{{.*}}@destroy_enum_value(
 // CHECK-NEXT:  entry:
-// CHECK-NEXT:    trunc
-// CHECK-NEXT:    zext
 // CHECK-NEXT:    call{{.*}}@destroy_enum(
 // CHECK-NEXT:    ret void
 sil @destroy_enum_value : $@convention(thin) (@owned MOEnum) -> () {
@@ -198,7 +196,6 @@ entry(%b : $MOEnum):
 // CHECK-NEXT:    load
 // CHECK-NEXT:    getelementptr
 // CHECK-NEXT:    load
-// CHECK-NEXT:    zext
 // CHECK-NEXT:    call{{.*}}@destroy_enum(
 // CHECK-NEXT:    ret void
 sil @destroy_enum_value_indirect : $@convention(thin) (@in MOEnum) -> () {
diff --git a/test/IRGen/moveonly_deinits.swift b/test/IRGen/moveonly_deinits.swift
index 1302610a18534..3c30170943138 100644
--- a/test/IRGen/moveonly_deinits.swift
+++ b/test/IRGen/moveonly_deinits.swift
@@ -66,11 +66,11 @@ var value: Bool { false }
 // IR:   br i1 {{%.*}}, label %[[BB1:[0-9]+]], label %[[BB2:[0-9]+]]
 //
 // IR: [[BB1]]:
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
-// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds %TSi, ptr [[GEP]], i32 0, i32 0
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
+// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[GEP]], i32 0, i32 0
 // IR-NEXT:   [[LHS:%.*]] = load i64, ptr [[GEP2]]
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
-// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds %TSi, ptr [[GEP]], i32 0, i32 0
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
+// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[GEP]], i32 0, i32 0
 // IR-NEXT:   [[RHS:%.*]] = load i64, ptr [[GEP2]]
 // IR-NEXT:   call swiftcc void @"$s16moveonly_deinits27consumeIntPairWithoutDeinityyAA0defG0VnF"(i64 [[LHS]], i64 [[RHS]])
 // IR-NEXT:   br label %[[CONT:[0-9]+]]
@@ -95,21 +95,21 @@ public func testIntPairWithoutDeinit() {
 // IR: br i1 {{%.*}}, label %[[BB1:[0-9]+]], label %[[BB2:[0-9]+]]
 //
 // IR: [[BB1]]:
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
-// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds %TSi, ptr [[GEP]], i32 0, i32 0
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
+// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[GEP]], i32 0, i32 0
 // IR-NEXT:   [[LHS:%.*]] = load i64, ptr [[GEP2]]
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
-// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds %TSi, ptr [[GEP]], i32 0, i32 0
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
+// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[GEP]], i32 0, i32 0
 // IR-NEXT:   [[RHS:%.*]] = load i64, ptr [[GEP2]]
 // IR-NEXT:  call swiftcc void @"$s16moveonly_deinits24consumeIntPairWithDeinityyAA0defG0VnF"(
 // IR-NEXT:  br label %[[CONT:[0-9]+]]
 //
 // IR: [[BB2]]:
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
-// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds %TSi, ptr [[GEP]], i32 0, i32 0
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
+// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[GEP]], i32 0, i32 0
 // IR-NEXT:   [[LHS:%.*]] = load i64, ptr [[GEP2]]
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
-// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds %TSi, ptr [[GEP]], i32 0, i32 0
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
+// IR-NEXT:   [[GEP2:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[GEP]], i32 0, i32 0
 // IR-NEXT:   [[RHS:%.*]] = load i64, ptr [[GEP2]]
 // IR-NEXT:  call swiftcc void @"$s16moveonly_deinits17IntPairWithDeinitVfD"(i64 [[LHS]], i64 [[RHS]])
 // IR-NEXT:  br label %[[CONT]]
@@ -130,9 +130,9 @@ public func testIntPairWithDeinit() {
 // IR:   br i1 {{%.*}}, label %[[BB1:[0-9]+]], label %[[BB2:[0-9]+]]
 //
 // IR: [[BB1]]:
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
 // IR-NEXT:   [[LHS:%.*]] = load ptr, ptr [[GEP]]
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
 // IR-NEXT:   [[RHS:%.*]] = load ptr, ptr [[GEP]]
 // IR-NEXT:   call swiftcc void @"$s16moveonly_deinits29consumeKlassPairWithoutDeinityyAA0defG0VnF"(ptr [[LHS]], ptr [[RHS]])
 // IR-NEXT:   br label %[[CONT:[0-9]+]]
@@ -157,17 +157,17 @@ public func testKlassPairWithoutDeinit() {
 // IR:   br i1 {{%.*}}, label %[[BB1:[0-9]+]], label %[[BB2:[0-9]+]]
 //
 // IR: [[BB1]]:
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
 // IR-NEXT:   [[LHS:%.*]] = load ptr, ptr [[GEP]]
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
 // IR-NEXT:   [[RHS:%.*]] = load ptr, ptr [[GEP]]
 // IR-NEXT:  call swiftcc void @"$s16moveonly_deinits26consumeKlassPairWithDeinityyAA0defG0VnF"(ptr [[LHS]], ptr [[RHS]])
 // IR-NEXT:  br label %[[CONT:[0-9]+]]
 //
 // IR: [[BB2]]:
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 0
 // IR-NEXT:   [[LHS:%.*]] = load ptr, ptr [[GEP]]
-// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
+// IR-NEXT:   [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
 // IR-NEXT:   [[RHS:%.*]] = load ptr, ptr [[GEP]]
 // IR-NEXT:  call swiftcc void @"$s16moveonly_deinits19KlassPairWithDeinitVfD"(ptr [[LHS]], ptr [[RHS]])
 // IR-NEXT:  br label %[[CONT]]
@@ -230,10 +230,9 @@ func consumeKlassEnumPairWithDeinit(_ x: __owned KlassEnumPairWithDeinit) { }
 //
 // IR: [[BB1]]:
 // IR-NEXT:  [[LHS:%.*]] = load i64, ptr [[ALLOCA]]
-// IR-NEXT:  [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
-// IR-NEXT:  [[RHS:%.*]] = load i1, ptr [[GEP]]
-// IR-NEXT:  [[RHS_ZEXT:%.*]] = zext i1 [[RHS]]
-// IR-NEXT:   call swiftcc void @"$s16moveonly_deinits31consumeIntEnumPairWithoutDeinityyAA0defgH0OnF"(i64 [[LHS]], i8 [[RHS_ZEXT]])
+// IR-NEXT:  [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
+// IR-NEXT:  [[RHS:%.*]] = load i8, ptr [[GEP]]
+// IR-NEXT:   call swiftcc void @"$s16moveonly_deinits31consumeIntEnumPairWithoutDeinityyAA0defgH0OnF"(i64 [[LHS]], i8 [[RHS]])
 // IR-NEXT:   br label %[[CONT:[0-9]+]]
 //
 // IR: [[BB2]]:
@@ -256,18 +255,16 @@ public func testIntEnumPairWithoutDeinit() {
 //
 // IR: [[BB1]]:
 // IR-NEXT:  [[LHS:%.*]] = load i64, ptr [[ALLOCA]]
-// IR-NEXT:  [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
-// IR-NEXT:  [[RHS:%.*]] = load i1, ptr [[GEP]]
-// IR-NEXT:  [[RHS_ZEXT:%.*]] = zext i1 [[RHS]]
-// IR-NEXT:  call swiftcc void @"$s16moveonly_deinits28consumeIntEnumPairWithDeinityyAA0defgH0OnF"(i64 [[LHS]], i8 [[RHS_ZEXT]])
+// IR-NEXT:  [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
+// IR-NEXT:  [[RHS:%.*]] = load i8, ptr [[GEP]]
+// IR-NEXT:  call swiftcc void @"$s16moveonly_deinits28consumeIntEnumPairWithDeinityyAA0defgH0OnF"(i64 [[LHS]], i8 [[RHS]])
 // IR-NEXT:  br label %[[CONT:[0-9]+]]
 //
 // IR: [[BB2]]:
 // IR-NEXT:  [[LHS:%.*]] = load i64, ptr [[ALLOCA]]
-// IR-NEXT:  [[GEP:%.*]] = getelementptr inbounds [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
-// IR-NEXT:  [[RHS:%.*]] = load i1, ptr [[GEP]]
-// IR-NEXT:  [[RHS_ZEXT:%.*]] = zext i1 [[RHS]]
-// IR-NEXT:  call swiftcc void @"$s16moveonly_deinits21IntEnumPairWithDeinitOfD"(i64 [[LHS]], i8 [[RHS_ZEXT]])
+// IR-NEXT:  [[GEP:%.*]] = getelementptr inbounds{{.*}} [[TYPE]], ptr [[ALLOCA]], i32 0, i32 1
+// IR-NEXT:  [[RHS:%.*]] = load i8, ptr [[GEP]]
+// IR-NEXT:  call swiftcc void @"$s16moveonly_deinits21IntEnumPairWithDeinitOfD"(i64 [[LHS]], i8 [[RHS]])
 // IR-NEXT:  br label %[[CONT]]
 //
 // IR: [[CONT]]
@@ -404,7 +401,7 @@ func testSingleEnum() {
 
 // IR-LABEL: define {{.*}}swiftcc void @"$s16moveonly_deinits13testMultiEnumyyF"()
 func testMultiEnum() {
-  // IR: call void @"$s16moveonly_deinits6EMultiOWOe"(i1 true)
+  // IR: call void @"$s16moveonly_deinits6EMultiOWOe"(i8 1)
   _ = EMulti.b(OtherEmptyMoveOnlyWithDeinit())
 }
 
diff --git a/test/IRGen/moveonly_split_module_source_deinit.swift b/test/IRGen/moveonly_split_module_source_deinit.swift
index a9b1836263f0d..d684fcea3e64c 100644
--- a/test/IRGen/moveonly_split_module_source_deinit.swift
+++ b/test/IRGen/moveonly_split_module_source_deinit.swift
@@ -7,7 +7,7 @@
 
 // Make sure we call the deinit through the value witness table in the other module.
 
-// REFERRING_MODULE-LABEL: define {{.*}}swiftcc void @"$s6serverAAV4mainyyKFZ"(ptr swiftself %0, ptr noalias nocapture swifterror dereferenceable({{(8|4)}}) %1) {{.*}}{
+// REFERRING_MODULE-LABEL: define {{.*}}swiftcc void @"$s6serverAAV4mainyyKFZ"(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{(8|4)}}) %1) {{.*}}{
 // REFERRING_MODULE: [[SERVER:%.*]] = alloca %T6server8MoveOnlyV
 // REFERRING_MODULE: [[VALUE_WITNESS_TABLE:%.*]] = getelementptr inbounds ptr, ptr %"$s6server8MoveOnlyVN.valueWitnesses"
 // REFERRING_MODULE: [[VALUE_WITNESS:%.*]] = load ptr, ptr [[VALUE_WITNESS_TABLE]]
@@ -15,9 +15,9 @@
 
 // Make sure that in the other module, we do call the deinit directly from the value witness.
 // DEFINING_MODULE-LABEL: define internal void @"$s6server8MoveOnlyVwxx"(ptr noalias %object, ptr %MoveOnly) {{.*}} {
-// DEFINING_MODULE: [[VAR:%.*]] = getelementptr inbounds {{%.*}}, ptr %object
+// DEFINING_MODULE: [[VAR:%.*]] = getelementptr inbounds{{.*}} {{%.*}}, ptr %object
 // DEFINING_MODULE: [[LOADED_VAR:%.*]] = load ptr, ptr [[VAR]],
-// DEFINING_MODULE: [[VAR2:%.*]] = getelementptr inbounds {{%.*}}, ptr %object
+// DEFINING_MODULE: [[VAR2:%.*]] = getelementptr inbounds{{.*}} {{%.*}}, ptr %object
 // DEFINING_MODULE: [[LOADED_VAR2:%.*]] = load ptr, ptr [[VAR2]],
 // DEFINING_MODULE: call swiftcc void @"$s6server8MoveOnlyVfD"(ptr [[LOADED_VAR]], ptr [[LOADED_VAR2]])
 @main
diff --git a/test/IRGen/moveonly_value_functions.sil b/test/IRGen/moveonly_value_functions.sil
index 2c3e4625ab694..f7f2eae7bf0d4 100644
--- a/test/IRGen/moveonly_value_functions.sil
+++ b/test/IRGen/moveonly_value_functions.sil
@@ -29,7 +29,7 @@ sil @deinit_count : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (move
 // CHECK:       entry:
 // CHECK:         [[CELL_VWT_ADDR:%[^,]+]] = getelementptr inbounds ptr, ptr %"_Cell<Value>", [[INT]] -1
 // CHECK:         %"_Cell<Value>.valueWitnesses" = load ptr, ptr [[CELL_VWT_ADDR]]
-// CHECK:         [[CELL_SIZE_ADDR:%[^,]+]] = getelementptr inbounds %swift.vwtable
+// CHECK:         [[CELL_SIZE_ADDR:%[^,]+]] = getelementptr inbounds{{.*}} %swift.vwtable
 //           :        ptr %"_Cell<Value>.valueWitnesses",
 // CHECK-SAME:        i32 0
 // CHECK-SAME:        i32 8
diff --git a/test/IRGen/moveonly_value_functions.swift b/test/IRGen/moveonly_value_functions.swift
index f14abc9f87622..8edd08684fddf 100644
--- a/test/IRGen/moveonly_value_functions.swift
+++ b/test/IRGen/moveonly_value_functions.swift
@@ -198,7 +198,7 @@ public func takeOuterDeinitingNC_1<T>(_ t: consuming OuterDeinitingNC_1<T>) {
 // CHECK:         [[INNER_DEINITING_RELEASABLE_NC_METADATA:%[^,]+]] = extractvalue %swift.metadata_response [[RESPONSE]]
 // CHECK:         call swiftcc void @"$s24moveonly_value_functions26InnerDeinitingReleasableNCVfD"(
 // CHECK-SAME:        ptr [[INNER_DEINITING_RELEASABLE_NC_METADATA]],
-//           :        ptr noalias nocapture swiftself dereferenceable(64) %deinit.arg)
+//           :        ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(64) %deinit.arg)
 // CHECK:       }
 public func takeOuterNC_1<T>(_ o: consuming OuterNC_1<T>) {
   external_symbol()
@@ -295,7 +295,7 @@ public func takeGenericContext_1OuterNC_1<T : P>(_ e: consuming GenericContext_1
 public func takeOuterSinglePayloadNC_1<T>(_ e: consuming OuterSinglePayloadNC_1<T>) {}
 
 // CHECK-LABEL: define{{.*}} @"$s24moveonly_value_functions26takeOuterSinglePayloadNC_2yyAA0efgH2_2OyxGnlF"(
-//           :      ptr noalias nocapture dereferenceable(64) %0, 
+//           :      ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(64) %0, 
 // CHECK-SAME:      ptr %T)
 // CHECK-SAME:  {
 // CHECK:         call{{.*}} @"$s24moveonly_value_functions22OuterSinglePayloadNC_2OyxGlWOh"(
@@ -388,7 +388,7 @@ public func takeOuterMultiPayloadNC_1<T>(_ e: consuming OuterMultiPayloadNC_1<T>
 // CHECK:       }
 public func takeOuterMultiPayloadNC_2<T>(_ e: consuming OuterMultiPayloadNC_2<T>) {}
 // CHECK-LABEL: define{{.*}} @"$s24moveonly_value_functions25takeOuterMultiPayloadNC_3yyAA0efgH2_3OyxGnlF"(
-//           :      ptr noalias nocapture dereferenceable(64) %0, 
+//           :      ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(64) %0, 
 // CHECK-SAME:      ptr %T)
 // CHECK-SAME:  {
 // CHECK:         call{{.*}} @"$s24moveonly_value_functions21OuterMultiPayloadNC_3OyxGlWOh"(
diff --git a/test/IRGen/moveonly_value_functions_onone.swift b/test/IRGen/moveonly_value_functions_onone.swift
index 9530a4b82bc62..2500c9daa5b90 100644
--- a/test/IRGen/moveonly_value_functions_onone.swift
+++ b/test/IRGen/moveonly_value_functions_onone.swift
@@ -195,7 +195,7 @@ public func takeOuterDeinitingNC_1<T>(_ t: consuming OuterDeinitingNC_1<T>) {
 // CHECK:         [[INNER_DEINITING_RELEASABLE_NC_METADATA:%[^,]+]] = extractvalue %swift.metadata_response [[RESPONSE]]
 // CHECK:         call swiftcc void @"$s30moveonly_value_functions_onone26InnerDeinitingReleasableNCVfD"(
 // CHECK-SAME:        ptr [[INNER_DEINITING_RELEASABLE_NC_METADATA]],
-//           :        ptr noalias nocapture swiftself dereferenceable(64) %deinit.arg)
+//           :        ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(64) %deinit.arg)
 // CHECK:       }
 public func takeOuterNC_1<T>(_ o: consuming OuterNC_1<T>) {
   external_symbol()
@@ -288,7 +288,7 @@ public func takeGenericContext_1OuterNC_1<T : P>(_ e: consuming GenericContext_1
 public func takeOuterSinglePayloadNC_1<T>(_ e: consuming OuterSinglePayloadNC_1<T>) {}
 
 // CHECK-LABEL: define{{.*}} @"$s30moveonly_value_functions_onone26takeOuterSinglePayloadNC_2yyAA0fghI2_2OyxGnlF"(
-//           :      ptr noalias nocapture dereferenceable(64) %0, 
+//           :      ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(64) %0, 
 // CHECK-SAME:      ptr %T)
 // CHECK-SAME:  {
 // CHECK:         call{{.*}} @"$s30moveonly_value_functions_onone22OuterSinglePayloadNC_2OyxGlWOh"(
@@ -305,7 +305,7 @@ public func takeOuterSinglePayloadNC_1<T>(_ e: consuming OuterSinglePayloadNC_1<
 // CHECK:         [[METADATA:%[^,]+]] = extractvalue %swift.metadata_response [[RESPONSE]], 0
 // CHECK:         call swiftcc void @"$s30moveonly_value_functions_onone26InnerDeinitingReleasableNCVfD"(
 // CHECK-SAME:        ptr [[METADATA]],
-//           :        ptr noalias nocapture swiftself dereferenceable(64) %0)
+//           :        ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(64) %0)
 // CHECK:       }
 public func takeOuterSinglePayloadNC_2<T>(_ e: consuming OuterSinglePayloadNC_2<T>) {}
 
@@ -383,7 +383,7 @@ public func takeOuterMultiPayloadNC_1<T>(_ e: consuming OuterMultiPayloadNC_1<T>
 // CHECK:       }
 public func takeOuterMultiPayloadNC_2<T>(_ e: consuming OuterMultiPayloadNC_2<T>) {}
 // CHECK-LABEL: define{{.*}} @"$s30moveonly_value_functions_onone25takeOuterMultiPayloadNC_3yyAA0fghI2_3OyxGnlF"(
-//           :      ptr noalias nocapture dereferenceable(64) %0, 
+//           :      ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(64) %0, 
 // CHECK-SAME:      ptr %T)
 // CHECK-SAME:  {
 // CHECK:         call{{.*}} @"$s30moveonly_value_functions_onone21OuterMultiPayloadNC_3OyxGlWOh"(
diff --git a/test/IRGen/multi_file_resilience.swift b/test/IRGen/multi_file_resilience.swift
index c3742a80a90da..4538ea2aed631 100644
--- a/test/IRGen/multi_file_resilience.swift
+++ b/test/IRGen/multi_file_resilience.swift
@@ -23,7 +23,7 @@
 // CHECK-arm64e: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
 //   Allocate 'copy'.
-// CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+// CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
 // CHECK: [[SIZE:%.*]] = load [[INT]], ptr [[SIZE_ADDR]]
 // CHECK: [[ALLOCA:%.*]] = alloca i8, [[INT]] [[SIZE]],
 //   Perform 'initializeWithCopy' via the VWT instead of trying to inline it.
diff --git a/test/IRGen/multi_module_resilience.swift b/test/IRGen/multi_module_resilience.swift
index 97fb2a0928d89..74616044c9eaf 100644
--- a/test/IRGen/multi_module_resilience.swift
+++ b/test/IRGen/multi_module_resilience.swift
@@ -22,7 +22,7 @@ import OtherModule
 // CHECK-arm64e: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
 //   Allocate 'copy'.
-// CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+// CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
 // CHECK: [[SIZE:%.*]] = load [[INT]], ptr [[SIZE_ADDR]]
 // CHECK: [[ALLOCA:%.*]] = alloca i8, [[INT]] [[SIZE]],
 //   Perform 'initializeWithCopy' via the VWT instead of trying to inline it.
@@ -43,7 +43,7 @@ public func copyFoo(foo: Foo) -> Foo {
 // CHECK-arm64e: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
 //   Allocate 'copy'.
-// CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+// CHECK: [[SIZE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
 // CHECK: [[SIZE:%.*]] = load [[INT]], ptr [[SIZE_ADDR]]
 // CHECK: [[ALLOCA:%.*]] = alloca i8, [[INT]] [[SIZE]],
 //   Perform 'initializeWithCopy' via the VWT instead of trying to inline it.
diff --git a/test/IRGen/multi_payload_shifting.swift b/test/IRGen/multi_payload_shifting.swift
index 253f6c5467d71..1ef8792f461b1 100644
--- a/test/IRGen/multi_payload_shifting.swift
+++ b/test/IRGen/multi_payload_shifting.swift
@@ -25,7 +25,7 @@ enum Node {
 }
 
 // CHECK: define internal i32 @"$s22multi_payload_shifting4NodeOwet"(ptr noalias %value, i32 %numEmptyCases, ptr %Node)
-// CHECK:  [[ADDR:%.*]] = getelementptr inbounds { i64, i64, i64, i8 }, ptr {{.*}}, i32 0, i32 3
+// CHECK:  [[ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64, i8 }, ptr {{.*}}, i32 0, i32 3
 // CHECK:  [[BYTE:%.*]] = load i8, ptr [[ADDR]]
 // Make sure we zext before we shift.
 // CHECK:  [[ZEXT:%.*]] = zext i8 [[BYTE]] to i32
diff --git a/test/IRGen/non_fixed_return.swift b/test/IRGen/non_fixed_return.swift
index ec84250f3e596..080ebd8864aa4 100644
--- a/test/IRGen/non_fixed_return.swift
+++ b/test/IRGen/non_fixed_return.swift
@@ -55,17 +55,17 @@ func create<T>(_ t: T) -> C<T> {
 // We use opaque storage types because LLVM performs type based analysis based
 // on the sret storage type which goes wrong with non fixed types.
 
-// CHECK-LABEL: define hidden swiftcc void @"$s16non_fixed_return1CVACyxGycfC"(ptr noalias sret(%swift.opaque) %0
+// CHECK-LABEL: define hidden swiftcc void @"$s16non_fixed_return1CVACyxGycfC"(ptr noalias sret(%swift.opaque){{.*}} %0
 
 // CHECK-LABEL: define hidden swiftcc void @"$s16non_fixed_return6createyAA1CVyxGxlF"(ptr noalias sret(%swift.opaque) %0, ptr noalias %1, ptr %T)
 // CHECK:  call swiftcc void @"$s16non_fixed_return1CVACyxGycfC"(ptr noalias sret(%swift.opaque) %0
 // CHECK:  ret void
 
 // Make sure we don't loose the stores for the optional UInt32? in optimize mode.
-// OPT-LABEL: define hidden swiftcc void @"$s16non_fixed_return1CVACyxGycfC"(ptr noalias sret(%swift.opaque) %0
+// OPT-LABEL: define hidden swiftcc void @"$s16non_fixed_return1CVACyxGycfC"(ptr noalias sret(%swift.opaque){{.*}} %0
 // OPT:  store i32 0, ptr [[BASE:%[0-9]+]]
-// OPT:  [[ADDR2:%.*]] = getelementptr inbounds i8, ptr [[BASE]], i64 4
-// OPT:  store i1 true, ptr [[ADDR2]]
-// OPT:  [[ADDR4:%.*]] = getelementptr inbounds i8, ptr [[BASE]], i64 8
+// OPT:  [[ADDR2:%.*]] = getelementptr inbounds{{.*}} i8, ptr [[BASE]], i64 4
+// OPT:  store i8 1, ptr [[ADDR2]]
+// OPT:  [[ADDR4:%.*]] = getelementptr inbounds{{.*}} i8, ptr [[BASE]], i64 8
 // OPT: call void @llvm.memset.p0.i64(ptr {{.*}}[[ADDR4]], i8 0, i64 16, i1 false)
 // OPT: ret void
diff --git a/test/IRGen/noncopyable_field_descriptors.swift b/test/IRGen/noncopyable_field_descriptors.swift
index 72678dac4b596..eb62fbf590419 100644
--- a/test/IRGen/noncopyable_field_descriptors.swift
+++ b/test/IRGen/noncopyable_field_descriptors.swift
@@ -39,16 +39,16 @@ public struct NonCopyable: ~Copyable { }
 // 'MF' constant as a separator that precedes each field descriptor.
 
 // NEW: @"$s4test8CC_TestsCMF" =
-// NEW-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyxG.3"
+// NEW-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyxG noncopyable
 // NEW-SAME: @"symbolic _____yq_G 4test21ConditionallyCopyableOAARi_zrlE"
-// NEW-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyAA03NonC0VG.4"
+// NEW-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyAA03NonC0VG noncopyable
 // NEW-SAME: @"symbolic _____ySSG 4test21ConditionallyCopyableOAARi_zrlE"
 
 // OLD: @"$s4test8CC_TestsCMF" =
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyxG.3"
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyq_G.4"
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyAA03NonC0VG.5"
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOySSG.6"
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyxG noncopyable
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyq_G
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOyAA03NonC0VG noncopyable
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test21ConditionallyCopyableOySSG
 public class CC_Tests<NCG: ~Copyable, T> {
   var ccNCG: ConditionallyCopyable<NCG> = .none
   var ccT: ConditionallyCopyable<T> = .none
@@ -62,16 +62,16 @@ public class CC_Tests<NCG: ~Copyable, T> {
 /// fields until a future runtime says they're safe to reflect.
 
 // NEW: @"$s4test8NC_TestsCMF" =
-// NEW-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyxG.5"
-// NEW-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyq_G.6"
-// NEW-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyAA03NonC0VG.7"
-// NEW-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOySSG.8"
+// NEW-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyxG noncopyable
+// NEW-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyq_G noncopyable
+// NEW-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyAA03NonC0VG noncopyable
+// NEW-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOySSG noncopyable
 
 // OLD: @"$s4test8NC_TestsCMF" =
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyxG.7"
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyq_G.8"
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyAA03NonC0VG.9"
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOySSG.10"
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyxG noncopyable
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyq_G noncopyable
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOyAA03NonC0VG noncopyable
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test13NeverCopyableOySSG noncopyable
 public class NC_Tests<NCG: ~Copyable, T> {
   var ncNCG: NeverCopyable<NCG> = .none
   var ncT: NeverCopyable<T> = .none
@@ -83,7 +83,7 @@ public class NC_Tests<NCG: ~Copyable, T> {
 // NEW: @"$s4test17StdlibTypes_TestsCMF" =
 // NEW-SAME: @"symbolic xSg"
 // NEW-SAME: @"symbolic q_Sg"
-// NEW-SAME: @"get_type_metadata Ri_zr0_l4test11NonCopyableVSg.9"
+// NEW-SAME: @"get_type_metadata Ri_zr0_l4test11NonCopyableVSg noncopyable
 // NEW-SAME: @"symbolic SSSg"
 // NEW-SAME: @"symbolic SPyxG"
 // NEW-SAME: @"symbolic SPyq_G"
@@ -93,7 +93,7 @@ public class NC_Tests<NCG: ~Copyable, T> {
 // OLD: @"$s4test17StdlibTypes_TestsCMF" =
 // OLD-SAME: @"symbolic xSg"
 // OLD-SAME: @"symbolic q_Sg"
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test11NonCopyableVSg.11"
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test11NonCopyableVSg noncopyable
 // OLD-SAME: @"symbolic SSSg"
 // OLD-SAME: @"symbolic SPyxG"
 // OLD-SAME: @"symbolic SPyq_G"
@@ -115,13 +115,13 @@ public class StdlibTypes_Tests<NCG: ~Copyable, T> {
 // NEW: @"$s4test19PlainlyStored_TestsCMF" =
 // NEW-SAME: @"symbolic x"
 // NEW-SAME: @"symbolic q_"
-// NEW-SAME: @"get_type_metadata Ri_zr0_l4test11NonCopyableV.10"
+// NEW-SAME: @"get_type_metadata Ri_zr0_l4test11NonCopyableV noncopyable
 // NEW-SAME: @"symbolic SS"
 
 // OLD: @"$s4test19PlainlyStored_TestsCMF" =
 // OLD-SAME: @"symbolic x"
 // OLD-SAME: @"symbolic q_"
-// OLD-SAME: @"get_type_metadata Ri_zr0_l4test11NonCopyableV.12"
+// OLD-SAME: @"get_type_metadata Ri_zr0_l4test11NonCopyableV noncopyable
 // OLD-SAME: @"symbolic SS"
 public class PlainlyStored_Tests<NCG: ~Copyable, T> {
   var ncg: NCG
diff --git a/test/IRGen/noncopyable_metadata_requests.swift b/test/IRGen/noncopyable_metadata_requests.swift
index d0981d9be0c3c..4c1335a9d5ea4 100644
--- a/test/IRGen/noncopyable_metadata_requests.swift
+++ b/test/IRGen/noncopyable_metadata_requests.swift
@@ -15,6 +15,7 @@
 
 // REQUIRES: OS=macosx
 // REQUIRES: executable_test
+// UNSUPPORTED: back_deployment_runtime || use_os_stdlib
 
 
 // This type's generic parameter is noncopyable, so older runtimes can't
diff --git a/test/IRGen/noncopyable_runtime_back_compat.swift b/test/IRGen/noncopyable_runtime_back_compat.swift
new file mode 100644
index 0000000000000..c99f631bac202
--- /dev/null
+++ b/test/IRGen/noncopyable_runtime_back_compat.swift
@@ -0,0 +1,42 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature SuppressedAssociatedTypes)
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_SuppressedAssociatedTypes
+
+// Noncopyable types are suppressed in field metadata in runtimes lacking
+// reflection support for them (currently all runtimes). However, we want
+// to ensure that noncopyable type metadata is still produced where it is
+// "load-bearing" to the generics system, such as in associated types in
+// protocol conformances.
+
+protocol Barrable: ~Copyable {
+}
+
+struct Bar<T: ~Copyable>: Barrable & ~Copyable {
+	var x: Int = 0
+}
+
+protocol F: ~Copyable {
+	associatedtype B: Barrable & ~Copyable
+}
+
+struct Foo: F & ~Copyable {
+	typealias B = Bar<Int>
+}
+
+func test<T: F & ~Copyable>(_: T.Type) {
+	print("\(T.B.self)")
+}
+
+// CHECK: Bar<Int>
+test(Foo.self)
+
+class Mirrored {
+	var noncopyableField: Bar<Int>
+
+	init() {
+		self.noncopyableField = Bar()
+	}
+}
+
+// CHECK: noncopyableField (0 elements)
+dump(Mirrored())
diff --git a/test/IRGen/nonisolated_nonsending_closure.swift b/test/IRGen/nonisolated_nonsending_closure.swift
new file mode 100644
index 0000000000000..32edb5efbb14d
--- /dev/null
+++ b/test/IRGen/nonisolated_nonsending_closure.swift
@@ -0,0 +1,55 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-build-swift-dylib(%t/%target-library-name(associated_type_by_mangled_name)) -target %target-cpu-apple-macosx15.0 -enable-library-evolution %S/Inputs/associated_type_by_mangled_name.swift -emit-module -emit-module-path %t/associated_type_by_mangled_name.swiftmodule -module-name associated_type_by_mangled_name
+// RUN: %target-codesign %t/%target-library-name(associated_type_by_mangled_name)
+
+// RUN: %target-swift-frontend -target %target-cpu-apple-macosx15.0 -I %t %s -emit-ir -o - | %FileCheck %s
+// RUN: %target-swift-frontend -target %target-cpu-apple-macosx26.0 -I %t %s -emit-ir -o - | %FileCheck %s -check-prefix CHECK-SUPPORTED
+
+// RUN: %target-build-swift -target %target-cpu-apple-macosx15.0 %s -lassociated_type_by_mangled_name -I %t -L %t -o %t/main15 %target-rpath(%t)
+// RUN: %target-codesign %t/main15
+
+// RUN: %target-run %t/main15 %t/%target-library-name(associated_type_by_mangled_name)
+
+// RUN: %target-build-swift -target %target-cpu-apple-macosx26.0 %s -lassociated_type_by_mangled_name -I %t -L %t -o %t/main26 %target-rpath(%t)
+// RUN: %target-codesign %t/main26
+
+// RUN: %target-run %t/main26 %t/%target-library-name(associated_type_by_mangled_name)
+
+// REQUIRES: executable_test
+// REQUIRES: OS=macosx
+// UNSUPPORTED: back_deployment_runtime || use_os_stdlib
+
+import associated_type_by_mangled_name
+
+protocol P: Sendable {
+    associatedtype T: Proto
+    func foo() -> T
+}
+
+struct PImpl: P {
+  func foo() -> some Proto {
+    return ProtoImpl(2)
+  }
+}
+
+// CHECK: @"get_type_metadata 30nonisolated_nonsending_closure1PRzl31associated_type_by_mangled_name9ProtoImplVyySiYaKYCcG.3" = linkonce_odr hidden constant <{ i8, i32, i8 }> <{ i8 9, i32 trunc (i64 sub (i64 ptrtoint (ptr @"get_type_metadata 30nonisolated_nonsending_closure1PRzl31associated_type_by_mangled_name9ProtoImplVyySiYaKYCcG" to i64), i64 ptrtoint (ptr getelementptr inbounds (<{ i8, i32, i8 }>, ptr @"get_type_metadata 30nonisolated_nonsending_closure1PRzl31associated_type_by_mangled_name9ProtoImplVyySiYaKYCcG.3", i32 0, i32 1) to i64)) to i32), i8 0 }>
+// CHECK: define linkonce_odr hidden ptr @"$s31associated_type_by_mangled_name9ProtoImplVyySiYaKYCcGACyxGAA0F0AAWl"() #1 {
+// CHECK:   call swiftcc %swift.metadata_response @"$s31associated_type_by_mangled_name9ProtoImplVyySiYaKYCcGMa"(i64 255)
+// CHECK: }
+
+// CHECK-SUPPORTED-NOT: @"get_type_metadata 30nonisolated_nonsending_closure1PRzl31associated_type_by_mangled_name9ProtoImplVyySiYaKYCcG.3"
+// CHECK-SUPPORTED: define linkonce_odr hidden ptr @"$s31associated_type_by_mangled_name9ProtoImplVyySiYaKYCcGACyxGAA0F0AAWl"() #1 {
+// CHECK-SUPPORTED:   call ptr @__swift_instantiateConcreteTypeFromMangledNameAbstract(ptr @"$s31associated_type_by_mangled_name9ProtoImplVyySiYaKYCcGMD")
+// CHECK-SUPPORTED: }
+struct MyStruct<T: P>: Proto {
+  typealias Closure = nonisolated(nonsending) (Int) async throws -> Void
+
+  let x: T
+
+  public var value: some Proto {
+    return ProtoImpl<Closure> { _ in }
+  }
+}
+
+print(makeThing(MyStruct(x: PImpl())))
diff --git a/test/IRGen/objc.swift b/test/IRGen/objc.swift
index 004813e7fc04b..8c1fe001958b8 100644
--- a/test/IRGen/objc.swift
+++ b/test/IRGen/objc.swift
@@ -139,7 +139,7 @@ class WeakObjC {
 // CHECK:  i32 1, !"Objective-C Version", i32 2}
 // CHECK:  i32 1, !"Objective-C Image Info Version", i32 0}
 // CHECK:  i32 1, !"Objective-C Image Info Section", !"__DATA,__objc_imageinfo,regular,no_dead_strip"}
-//   100796160 == (6 << 24) | (2 << 16) | (7 << 8).
-//     6 and 2 is the current major.minor version. 7 is the Swift ABI version.
-// CHECK:  i32 4, !"Objective-C Garbage Collection", i32 100796160}
+//   100861696 == (6 << 24) | (3 << 16) | (7 << 8).
+//     6 and 3 is the current major.minor version. 7 is the Swift ABI version.
+// CHECK:  i32 4, !"Objective-C Garbage Collection", i32 100861696}
 // CHECK:  i32 1, !"Swift Version", i32 7}
diff --git a/test/IRGen/objc_block.sil b/test/IRGen/objc_block.sil
index 277d3488cd90e..7133f42ba82e3 100644
--- a/test/IRGen/objc_block.sil
+++ b/test/IRGen/objc_block.sil
@@ -16,7 +16,7 @@ entry(%b : $@convention(block) (Foo) -> Foo, %x : $Foo):
 }
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @call_block(ptr %0, ptr %1) {{.*}} {
 // CHECK:       entry:
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr %0, i32 0, i32 3
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr %0, i32 0, i32 3
 // CHECK:         [[T1:%.*]] = load ptr, ptr [[T0]]
 // CHECK:         [[T4:%.*]] = call ptr [[T1]](ptr %0, ptr %1)
 // CHECK:         ret ptr [[T4]]
diff --git a/test/IRGen/objc_block_storage.sil b/test/IRGen/objc_block_storage.sil
index 5ecd6d590d1a5..5a80222fb5f5b 100644
--- a/test/IRGen/objc_block_storage.sil
+++ b/test/IRGen/objc_block_storage.sil
@@ -38,9 +38,9 @@ import gizmo
 // CHECK:   ptr [[NSRECT_BLOCK_SIGNATURE]]
 // CHECK: }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @project_block_storage(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @project_block_storage(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-NEXT:  entry:
-// CHECK-NEXT:    %1 = getelementptr inbounds { %objc_block, ptr }, ptr %0, i32 0, i32 1
+// CHECK-NEXT:    %1 = getelementptr inbounds{{.*}} { %objc_block, ptr }, ptr %0, i32 0, i32 1
 // CHECK-NEXT:    %2 = load ptr, ptr %1, align 8
 // CHECK-NEXT:    ret ptr %2
 // CHECK-NEXT:  }
@@ -51,9 +51,9 @@ entry(%0 : $*@block_storage Builtin.RawPointer):
   return %p : $Builtin.RawPointer
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc fp128 @overaligned_project_block_storage(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc fp128 @overaligned_project_block_storage(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK-NEXT:  entry:
-// CHECK-NEXT:    %1 = getelementptr inbounds { %objc_block, fp128 }, ptr %0, i32 0, i32 1
+// CHECK-NEXT:    %1 = getelementptr inbounds{{.*}} { %objc_block, fp128 }, ptr %0, i32 0, i32 1
 // CHECK-NEXT:    %2 = load fp128, ptr %1, align 16
 // CHECK-NEXT:    ret fp128 %2
 // CHECK-NEXT:  }
@@ -64,18 +64,18 @@ entry(%0 : $*@block_storage Builtin.FPIEEE128):
   return %p : $Builtin.FPIEEE128
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @init_block_header_trivial(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
-// CHECK:         [[HEADER:%.*]] = getelementptr inbounds { %objc_block, ptr }, ptr %0, i32 0, i32 0
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 0
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @init_block_header_trivial(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK:         [[HEADER:%.*]] = getelementptr inbounds{{.*}} { %objc_block, ptr }, ptr %0, i32 0, i32 0
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 0
 // CHECK:         store ptr [[BLOCK_ISA]], ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 1
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 1
 // --                  0x4000_0000 -- HAS_SIGNATURE
 // CHECK:         store i32 1073741824, ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 2
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 2
 // CHECK:         store i32 0, ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 3
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 3
 // CHECK:         store ptr @invoke_trivial, ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 4
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 4
 // CHECK:         store ptr [[TRIVIAL_BLOCK_DESCRIPTOR]], ptr [[T0]]
 // CHECK:         ret ptr %0
 sil @init_block_header_trivial : $@convention(thin) (@inout_aliasable @block_storage Builtin.RawPointer) -> @convention(block) () -> () {
@@ -86,7 +86,7 @@ entry(%0 : $*@block_storage Builtin.RawPointer):
 }
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} void @invoke_trivial(ptr %0) {{.*}} {
-// CHECK:         %1 = getelementptr inbounds { %objc_block, ptr }, ptr %0, i32 0, i32 1
+// CHECK:         %1 = getelementptr inbounds{{.*}} { %objc_block, ptr }, ptr %0, i32 0, i32 1
 sil @invoke_trivial : $@convention(c) (@inout_aliasable @block_storage Builtin.RawPointer) -> () {
 entry(%0 : $*@block_storage Builtin.RawPointer):
   %c = project_block_storage %0 : $*@block_storage Builtin.RawPointer
@@ -109,18 +109,18 @@ entry(%0 : $*@block_storage Builtin.RawPointer, %1 : $Int):
   return %1 : $Int
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @init_block_header_nontrivial(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @init_block_header_nontrivial(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK:         [[HEADER:%.*]] = getelementptr inbounds
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 0
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 0
 // CHECK:         store ptr [[BLOCK_ISA]], ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 1
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 1
 // --                  0x4200_0000 -- HAS_SIGNATURE, HAS_COPY_DISPOSE
 // CHECK:         store i32 1107296256, ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 2
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 2
 // CHECK:         store i32 0, ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 3
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 3
 // CHECK:         store ptr @invoke_nontrivial, ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 4
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 4
 // CHECK:         store ptr [[NONTRIVIAL_BLOCK_DESCRIPTOR]], ptr [[T0]]
 sil @init_block_header_nontrivial : $@convention(thin) (@inout_aliasable @block_storage Builtin.NativeObject) -> @convention(block) () -> () {
 entry(%0 : $*@block_storage Builtin.NativeObject):
@@ -131,8 +131,8 @@ entry(%0 : $*@block_storage Builtin.NativeObject):
 
 // CHECK:       define internal void [[NONTRIVIAL_BLOCK_COPY]]
 // CHECK-NEXT:  entry:
-// CHECK-NEXT:    %2 = getelementptr inbounds { %objc_block, ptr }, ptr %0, i32 0, i32 1
-// CHECK-NEXT:    %3 = getelementptr inbounds { %objc_block, ptr }, ptr %1, i32 0, i32 1
+// CHECK-NEXT:    %2 = getelementptr inbounds{{.*}} { %objc_block, ptr }, ptr %0, i32 0, i32 1
+// CHECK-NEXT:    %3 = getelementptr inbounds{{.*}} { %objc_block, ptr }, ptr %1, i32 0, i32 1
 // CHECK-NEXT:    %4 = load ptr, ptr %3, align 8
 // CHECK-NEXT:    call ptr @swift_retain(ptr returned %4) {{#[0-9]+}}
 // CHECK-NEXT:    store ptr %4, ptr %2, align 8
@@ -140,25 +140,25 @@ entry(%0 : $*@block_storage Builtin.NativeObject):
 
 // CHECK:       define internal void [[NONTRIVIAL_BLOCK_DISPOSE]]
 // CHECK-NEXT:  entry:
-// CHECK-NEXT:    %1 = getelementptr inbounds { %objc_block, ptr }, ptr %0, i32 0, i32 1
+// CHECK-NEXT:    %1 = getelementptr inbounds{{.*}} { %objc_block, ptr }, ptr %0, i32 0, i32 1
 // CHECK-NEXT:    %toDestroy = load ptr, ptr %1, align 8
 // CHECK-NEXT:    call void @swift_release(ptr %toDestroy) {{#[0-9]+}}
 // CHECK-NEXT:    ret void
 
 sil public_external @invoke_nontrivial : $@convention(c) (@inout_aliasable @block_storage Builtin.NativeObject) -> ()
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @init_block_header_stret(ptr nocapture dereferenceable({{.*}}) %0) {{.*}} {
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @init_block_header_stret(ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0) {{.*}} {
 // CHECK:         [[HEADER:%.*]] = getelementptr inbounds
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 0
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 0
 // CHECK:         store ptr [[BLOCK_ISA]], ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 1
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 1
 // --                  0x6000_0000 -- HAS_STRET, HAS_SIGNATURE
 // CHECK:         store i32 1610612736, ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 2
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 2
 // CHECK:         store i32 0, ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 3
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 3
 // CHECK:         store ptr @invoke_stret, ptr [[T0]]
-// CHECK:         [[T0:%.*]] = getelementptr inbounds %objc_block, ptr [[HEADER]], i32 0, i32 4
+// CHECK:         [[T0:%.*]] = getelementptr inbounds{{.*}} %objc_block, ptr [[HEADER]], i32 0, i32 4
 // CHECK:         store ptr [[STRET_BLOCK_DESCRIPTOR]], ptr [[T0]]
 sil @init_block_header_stret : $@convention(thin) (@inout_aliasable @block_storage Builtin.RawPointer) -> @convention(block) () -> NSRect {
 entry(%0 : $*@block_storage Builtin.RawPointer):
diff --git a/test/IRGen/objc_class_export.swift b/test/IRGen/objc_class_export.swift
index 4f3e467940a27..bfc8532b00320 100644
--- a/test/IRGen/objc_class_export.swift
+++ b/test/IRGen/objc_class_export.swift
@@ -87,13 +87,13 @@ struct BigStructWithNativeObjects {
     return NSRect(origin: NSPoint(x: 0, y: 0), 
                   size: NSSize(width: 0, height: 0))
   }
-  // CHECK: define internal void @"$s17objc_class_export3FooC6boundsSo6NSRectVyFTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2) {{[#0-9]*}} {
+  // CHECK: define internal void @"$s17objc_class_export3FooC6boundsSo6NSRectVyFTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2) {{[#0-9]*}} {
   // CHECK:   call swiftcc { double, double, double, double } @"$s17objc_class_export3FooC6boundsSo6NSRectVyF"(ptr swiftself %1)
 
   @objc func convertRectToBacking(r r: NSRect) -> NSRect {
     return r
   }
-  // CHECK: define internal void @"$s17objc_class_export3FooC20convertRectToBacking1rSo6NSRectVAG_tFTo"(ptr noalias nocapture sret({{.*}}) %0, ptr %1, ptr %2, ptr byval({{.*}} align 8 %3) {{[#0-9]*}} {
+  // CHECK: define internal void @"$s17objc_class_export3FooC20convertRectToBacking1rSo6NSRectVAG_tFTo"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr %1, ptr %2, ptr byval({{.*}} align 8 %3) {{[#0-9]*}} {
   // CHECK:   call swiftcc { double, double, double, double } @"$s17objc_class_export3FooC20convertRectToBacking1rSo6NSRectVAG_tF"(double {{.*}}, double {{.*}}, double {{.*}}, double {{.*}}, ptr swiftself %1)
 
   func doStuffToSwiftSlice(f f: [Int]) {
diff --git a/test/IRGen/objc_dealloc.sil b/test/IRGen/objc_dealloc.sil
index aecdf14bc3174..54a53824a7ecd 100644
--- a/test/IRGen/objc_dealloc.sil
+++ b/test/IRGen/objc_dealloc.sil
@@ -94,9 +94,9 @@ bb0(%0 : @unowned $SwiftGizmo):
   // Call super -dealloc.
   // CHECK: [[TMP:%.*]] = call swiftcc %swift.metadata_response @"$s12objc_dealloc10SwiftGizmoCMa"(i64 0)
   // CHECK-NEXT: [[T0:%.*]] = extractvalue %swift.metadata_response [[TMP]], 0
-  // CHECK-NEXT: [[OBJC_SUPER_RECEIVER:%[a-zA-Z0-9]+]] = getelementptr inbounds %objc_super, ptr [[OBJC_SUPER]], i32 0, i32 0
+  // CHECK-NEXT: [[OBJC_SUPER_RECEIVER:%[a-zA-Z0-9]+]] = getelementptr inbounds{{.*}} %objc_super, ptr [[OBJC_SUPER]], i32 0, i32 0
   // CHECK-NEXT: store ptr %0, ptr [[OBJC_SUPER_RECEIVER]], align 8
-  // CHECK-NEXT: [[OBJC_SUPER_CLASS:%[a-zA-Z0-9]+]] = getelementptr inbounds %objc_super, ptr [[OBJC_SUPER]], i32 0, i32 1
+  // CHECK-NEXT: [[OBJC_SUPER_CLASS:%[a-zA-Z0-9]+]] = getelementptr inbounds{{.*}} %objc_super, ptr [[OBJC_SUPER]], i32 0, i32 1
   // CHECK-NEXT: store ptr [[T0]], ptr [[OBJC_SUPER_CLASS]], align 8
   // CHECK-NEXT: [[DEALLOC_SEL:%[a-zA-Z0-9]+]] = load ptr, ptr @"\01L_selector(dealloc)", align 8
   // CHECK-NEXT: call void @objc_msgSendSuper2(ptr [[OBJC_SUPER]], ptr [[DEALLOC_SEL]])
diff --git a/test/IRGen/objc_extensions.swift b/test/IRGen/objc_extensions.swift
index 059ca2df9c36a..c1bd20dec940b 100644
--- a/test/IRGen/objc_extensions.swift
+++ b/test/IRGen/objc_extensions.swift
@@ -13,7 +13,7 @@ import objc_extension_base
 // Check that metadata for nested enums added in extensions to imported classes
 // gets emitted concretely.
 
-// CHECK: [[CATEGORY_NAME:@.*]] = private constant [16 x i8] c"objc_extensions\00"
+// CHECK: [[CATEGORY_NAME:@.*]] = private unnamed_addr constant [16 x i8] c"objc_extensions\00"
 // CHECK: [[METHOD_TYPE:@.*]] = private unnamed_addr constant [8 x i8] c"v16@0:8\00"
 
 // CHECK-LABEL: @"_CATEGORY_PROTOCOLS_Gizmo_$_objc_extensions" = internal constant
@@ -230,8 +230,8 @@ extension FungingArray {
   // CHECK-SAME: (ptr %0, ptr swiftself %1)
   // CHECK: [[ALLOCA:%[^, =]+]] = alloca %Any, align 8
   // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_pMD"{{.*}}!dbg
-  // CHECK: {{%[^, =]+}} = getelementptr inbounds %Any, ptr [[ALLOCA]], i32 0, i32 0
-  // CHECK: [[ANYBUF:%[^, =]+]] = getelementptr inbounds %Any, ptr [[ALLOCA]], i32 0, i32 0
+  // CHECK: {{%[^, =]+}} = getelementptr inbounds{{.*}} %Any, ptr [[ALLOCA]], i32 0, i32 0
+  // CHECK: [[ANYBUF:%[^, =]+]] = getelementptr inbounds{{.*}} %Any, ptr [[ALLOCA]], i32 0, i32 0
   // CHECK: [[BUFPTR:%[^, =]+]] = {{.*}} [[ANYBUF]]
   // CHECK: store {{.*}} %0, {{.*}} [[BUFPTR]]
   // CHECK: call swiftcc void @"$s15objc_extensions11opaquePrintyyypF"(ptr {{.*}} [[ALLOCA]])
@@ -249,8 +249,8 @@ extension FungingArray {
   // CHECK: [[ALLOCA:%[^, =]+]] = alloca %Any, align 8
   // CHECK: @__swift_instantiateConcreteTypeFromMangledName{{.*}}@"$sSo9NSFunging_pMD"{{.*}}!dbg
   // CHECK: [[OBJC_CLASS:%[^, =]+]] = call ptr @swift_getObjCClassFromMetadata(ptr %0)
-  // CHECK: {{%[^, =]+}} = getelementptr inbounds %Any, ptr [[ALLOCA]], i32 0, i32 0
-  // CHECK: [[ANYBUF:%[^, =]+]] = getelementptr inbounds %Any, ptr [[ALLOCA]], i32 0, i32 0
+  // CHECK: {{%[^, =]+}} = getelementptr inbounds{{.*}} %Any, ptr [[ALLOCA]], i32 0, i32 0
+  // CHECK: [[ANYBUF:%[^, =]+]] = getelementptr inbounds{{.*}} %Any, ptr [[ALLOCA]], i32 0, i32 0
   // CHECK: [[BUFPTR:%[^, =]+]] = {{.*}} [[ANYBUF]]
   // CHECK: store {{.*}} [[OBJC_CLASS]], {{.*}} [[BUFPTR]]
   // CHECK: call swiftcc void @"$s15objc_extensions11opaquePrintyyypF"(ptr {{.*}} [[ALLOCA]])
diff --git a/test/IRGen/objc_function_merge.swift b/test/IRGen/objc_function_merge.swift
index c2e07effb02fc..19ee8d37c6857 100644
--- a/test/IRGen/objc_function_merge.swift
+++ b/test/IRGen/objc_function_merge.swift
@@ -43,9 +43,9 @@ class Derived : Base {
 
 
 // Check if the objc methods are not generated with the unnamed_addr attribute.
-// CHECK-IR-DAG: define {{.*}} @"$s4test4BaseC20supportsSecureCodingSbvgZTo"({{[^\)]*}}) #{{[0-9]+}} {
-// CHECK-IR-DAG: define {{.*}} @"$s4test4BaseC6encode4withySo7NSCoderC_tFTo"({{[^\)]*}}) #{{[0-9]+}} {
-// CHECK-IR-DAG: define {{.*}} @"$s4test7DerivedC20supportsSecureCodingSbvgZTo"({{[^\)]*}}) #{{[0-9]+}} {
+// CHECK-IR-DAG: define {{.*}} @"$s4test4BaseC20supportsSecureCodingSbvgZTo"({{.*}}) #{{[0-9]+}} {
+// CHECK-IR-DAG: define {{.*}} @"$s4test4BaseC6encode4withySo7NSCoderC_tFTo"({{.*}}) #{{[0-9]+}} {
+// CHECK-IR-DAG: define {{.*}} @"$s4test7DerivedC20supportsSecureCodingSbvgZTo"({{.*}}) #{{[0-9]+}} {
 
 let d = Derived(s: "")
 if #available(macOS 10.13, iOS 11, tvOS 11, watchOS 4, *) {
diff --git a/test/IRGen/objc_generic_protocol_conformance.swift b/test/IRGen/objc_generic_protocol_conformance.swift
index a87cebe9733e9..44b6e359305ce 100644
--- a/test/IRGen/objc_generic_protocol_conformance.swift
+++ b/test/IRGen/objc_generic_protocol_conformance.swift
@@ -9,4 +9,4 @@ protocol P {
 extension Foo: P {}
 
 // SIL-LABEL: sil private [transparent] [thunk] [ossa] @$sSo3FooCyxG33objc_generic_protocol_conformance1PA2dEP3fooyyFTW {{.*}} @pseudogeneric
-// IR-LABEL: define internal swiftcc void @"$sSo3FooCyxG33objc_generic_protocol_conformance1PA2dEP3fooyyFTW"(ptr noalias nocapture swiftself dereferenceable({{4|8}}) %0, ptr{{( %Self)?}}, ptr{{( %SelfWitnessTable)?}})
+// IR-LABEL: define internal swiftcc void @"$sSo3FooCyxG33objc_generic_protocol_conformance1PA2dEP3fooyyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{4|8}}) %0, ptr{{( %Self)?}}, ptr{{( %SelfWitnessTable)?}})
diff --git a/test/IRGen/objc_implementation.swift b/test/IRGen/objc_implementation.swift
index 844ef699cbc0d..0350787bb679d 100644
--- a/test/IRGen/objc_implementation.swift
+++ b/test/IRGen/objc_implementation.swift
@@ -35,7 +35,7 @@
 // CHECK-SAME: { ptr, ptr, ptr } { ptr @"\01L_selector_data(mutableCopyWithZone:)", ptr @".str.11.@24@0:8^v16", ptr @"$sSo9ImplClassC19objc_implementationE11mutableCopy4withypSg10ObjectiveC6NSZoneVSg_tFTo{{(\.ptrauth)?}}" }
 // CHECK-SAME: { ptr, ptr, ptr } { ptr @"\01L_selector_data(dealloc)", ptr @".str.7.v16@0:8", ptr @"$sSo9ImplClassC19objc_implementationEfDTo{{(\.ptrauth)?}}" }, { ptr, ptr, ptr } { ptr [[selector_data__cxx_destruct]], ptr @".str.7.v16@0:8", ptr @"$sSo9ImplClassCfETo{{(\.ptrauth)?}}" }
 // CHECK-LABEL: @_IVARS_ImplClass = internal constant { i32, i32, [2 x { ptr, ptr, ptr, i32, i32 }] } { i32 32, i32 2, [2 x { ptr, ptr, ptr, i32, i32 }] [
-// CHECK-SAME: { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo9ImplClassC19objc_implementationE12implPropertys5Int32VvpWvd", ptr @.str.12.implProperty, ptr @.str.0., i32 2, i32 4 }
+// CHECK-SAME: { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo9ImplClassC19objc_implementationE12implPropertys5Int32VvpWvd", ptr @.str.12.implProperty, ptr @.str.1.i, i32 2, i32 4 }
 // CHECK-SAME: { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo9ImplClassC19objc_implementationE13implProperty2So8NSObjectCSgvpWvd", ptr @.str.13.implProperty2, ptr @.str.0., i32 3, i32 8 }
 // CHECK-LABEL: @_PROPERTIES_ImplClass = internal constant { i32, i32, [1 x { ptr, ptr }] } { i32 16, i32 1, [1 x { ptr, ptr }] [
 // CHECK-SAME: { ptr, ptr } { ptr @.str.12.implProperty, ptr @".str.18.Ti,N,VimplProperty" }
@@ -103,7 +103,7 @@
 // CHECK: @"OBJC_METACLASS_$_NoInitImplClass" = global %objc_class { ptr @"OBJC_METACLASS_$_NSObject", ptr @"OBJC_METACLASS_$_NSObject", ptr @_objc_empty_cache, ptr null, i64 ptrtoint (ptr @_METACLASS_DATA_NoInitImplClass to i64) }, align 8
 // CHECK: @_METACLASS_DATA_NoInitImplClass = internal constant { i32, i32, i32, i32, ptr, ptr, ptr, ptr, ptr, ptr, ptr } { i32 129, i32 40, i32 40, i32 0, ptr null, ptr @.str.15.NoInitImplClass, ptr null, ptr null, ptr null, ptr null, ptr null }, section "__DATA, __objc_const", align 8
 // CHECK: @_INSTANCE_METHODS_NoInitImplClass = internal constant { i32, i32, [9 x { ptr, ptr, ptr }] } { i32 24, i32 9, [9 x { ptr, ptr, ptr }] [{ ptr, ptr, ptr } { ptr @"\01L_selector_data(s1)", ptr @".str.7.@16@0:8", ptr @"$sSo15NoInitImplClassC19objc_implementationE2s1SSvgTo" }, { ptr, ptr, ptr } { ptr @"\01L_selector_data(s2)", ptr @".str.7.@16@0:8", ptr @"$sSo15NoInitImplClassC19objc_implementationE2s2SSvgTo" }, { ptr, ptr, ptr } { ptr @"\01L_selector_data(setS2:)", ptr @".str.10.v24@0:8@16", ptr @"$sSo15NoInitImplClassC19objc_implementationE2s2SSvsTo" }, { ptr, ptr, ptr } { ptr @"\01L_selector_data(s3)", ptr @".str.7.@16@0:8", ptr @"$sSo15NoInitImplClassC19objc_implementationE2s3SSvgTo" }, { ptr, ptr, ptr } { ptr @"\01L_selector_data(s4)", ptr @".str.7.@16@0:8", ptr @"$sSo15NoInitImplClassC19objc_implementationE2s4SSvgTo" }, { ptr, ptr, ptr } { ptr @"\01L_selector_data(setS4:)", ptr @".str.10.v24@0:8@16", ptr @"$sSo15NoInitImplClassC19objc_implementationE2s4SSvsTo" }, { ptr, ptr, ptr } { ptr @"\01L_selector_data(dealloc)", ptr @".str.7.v16@0:8", ptr @"$sSo15NoInitImplClassC19objc_implementationEfDTo" }, { ptr, ptr, ptr } { ptr @"\01L_selector_data(init)", ptr @".str.7.@16@0:8", ptr @"$sSo15NoInitImplClassC19objc_implementationEABycfcTo" }, { ptr, ptr, ptr } { ptr @"\01L_selector_data(.cxx_destruct)", ptr @".str.7.v16@0:8", ptr @"$sSo15NoInitImplClassCfETo" }] }, section "__DATA, __objc_data", align 8
-// CHECK: @_IVARS_NoInitImplClass = internal constant { i32, i32, [4 x { ptr, ptr, ptr, i32, i32 }] } { i32 32, i32 4, [4 x { ptr, ptr, ptr, i32, i32 }] [{ ptr, ptr, ptr, i32, i32 } { ptr @"$sSo15NoInitImplClassC19objc_implementationE2s1SSvpWvd", ptr @.str.2.s1, ptr @.str.0., i32 3, i32 16 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo15NoInitImplClassC19objc_implementationE2s2SSvpWvd", ptr @.str.2.s2, ptr @.str.0., i32 3, i32 16 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo15NoInitImplClassC19objc_implementationE2s3SSvpWvd", ptr @.str.2.s3, ptr @.str.0., i32 3, i32 16 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo15NoInitImplClassC19objc_implementationE2s4SSvpWvd", ptr @.str.2.s4, ptr @.str.0., i32 3, i32 16 }] }, section "__DATA, __objc_const", align 8
+// CHECK: @_IVARS_NoInitImplClass = internal constant { i32, i32, [4 x { ptr, ptr, ptr, i32, i32 }] } { i32 32, i32 4, [4 x { ptr, ptr, ptr, i32, i32 }] [{ ptr, ptr, ptr, i32, i32 } { ptr @"$sSo15NoInitImplClassC19objc_implementationE2s1SSvpWvd", ptr @.str.2.s1, ptr @".str.1.?", i32 3, i32 16 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo15NoInitImplClassC19objc_implementationE2s2SSvpWvd", ptr @.str.2.s2, ptr @".str.1.?", i32 3, i32 16 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo15NoInitImplClassC19objc_implementationE2s3SSvpWvd", ptr @.str.2.s3, ptr @".str.1.?", i32 3, i32 16 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo15NoInitImplClassC19objc_implementationE2s4SSvpWvd", ptr @.str.2.s4, ptr @".str.1.?", i32 3, i32 16 }] }, section "__DATA, __objc_const", align 8
 // CHECK: @_PROPERTIES_NoInitImplClass = internal constant { i32, i32, [4 x { ptr, ptr }] } { i32 16, i32 4, [4 x { ptr, ptr }] [{ ptr, ptr } { ptr @.str.2.s1, ptr @".str.16.T@\22NSString\22,N,R" }, { ptr, ptr } { ptr @.str.2.s2, ptr @".str.16.T@\22NSString\22,N,C" }, { ptr, ptr } { ptr @.str.2.s3, ptr @".str.16.T@\22NSString\22,N,R" }, { ptr, ptr } { ptr @.str.2.s4, ptr @".str.16.T@\22NSString\22,N,C" }] }, section "__DATA, __objc_const", align 8
 // CHECK: @_DATA_NoInitImplClass = internal constant { i32, i32, i32, i32, ptr, ptr, ptr, ptr, ptr, ptr, ptr } { i32 388, i32 8, i32 72, i32 0, ptr null, ptr @.str.15.NoInitImplClass, ptr @_INSTANCE_METHODS_NoInitImplClass, ptr null, ptr @_IVARS_NoInitImplClass, ptr null, ptr @_PROPERTIES_NoInitImplClass }, section "__DATA, __objc_data", align 8
 // CHECK: @"OBJC_CLASS_$_NoInitImplClass" = global <{ i64, ptr, ptr, ptr, i64 }> <{ i64 ptrtoint (ptr @"OBJC_METACLASS_$_NoInitImplClass" to i64), ptr @"OBJC_CLASS_$_NSObject", ptr @_objc_empty_cache, ptr null, i64 ptrtoint (ptr @_DATA_NoInitImplClass to i64) }>, section "__DATA,__objc_data, regular", align 8
@@ -153,7 +153,7 @@ open class SwiftSubclass: ImplClass {
 // TODO: Why the extra i32 field above?
 
 // Class
-// CHECK: @_IVARS_ImplClassWithResilientStoredProperty = internal constant { i32, i32, [4 x { ptr, ptr, ptr, i32, i32 }] } { i32 32, i32 4, [4 x { ptr, ptr, ptr, i32, i32 }] [{ ptr, ptr, ptr, i32, i32 } { ptr @"$sSo36ImplClassWithResilientStoredPropertyC19objc_implementationE9beforeInts5Int32VvpWvd", ptr @.str.9.beforeInt, ptr @.str.0., i32 2, i32 4 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo36ImplClassWithResilientStoredPropertyC19objc_implementationE6mirrors6MirrorVSgvpWvd", ptr @.str.6.mirror, ptr @.str.0., i32 0, i32 0 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo36ImplClassWithResilientStoredPropertyC19objc_implementationE13afterIntFinals5Int32VvpWvd", ptr @.str.13.afterIntFinal, ptr @.str.0., i32 2, i32 4 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo36ImplClassWithResilientStoredPropertyC19objc_implementationE8afterInts5Int32VvpWvd", ptr @.str.8.afterInt, ptr @.str.0., i32 2, i32 4 }] }, section "__DATA, __objc_const", align 8
+// CHECK: @_IVARS_ImplClassWithResilientStoredProperty = internal constant { i32, i32, [4 x { ptr, ptr, ptr, i32, i32 }] } { i32 32, i32 4, [4 x { ptr, ptr, ptr, i32, i32 }] [{ ptr, ptr, ptr, i32, i32 } { ptr @"$sSo36ImplClassWithResilientStoredPropertyC19objc_implementationE9beforeInts5Int32VvpWvd", ptr @.str.9.beforeInt, ptr @.str.1.i, i32 2, i32 4 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo36ImplClassWithResilientStoredPropertyC19objc_implementationE6mirrors6MirrorVSgvpWvd", ptr @.str.6.mirror, ptr @.str.0., i32 0, i32 0 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo36ImplClassWithResilientStoredPropertyC19objc_implementationE13afterIntFinals5Int32VvpWvd", ptr @.str.13.afterIntFinal, ptr @.str.0., i32 2, i32 4 }, { ptr, ptr, ptr, i32, i32 } { ptr @"$sSo36ImplClassWithResilientStoredPropertyC19objc_implementationE8afterInts5Int32VvpWvd", ptr @.str.8.afterInt, ptr @.str.1.i, i32 2, i32 4 }] }, section "__DATA, __objc_const", align 8
 // CHECK: @_DATA_ImplClassWithResilientStoredProperty = internal constant { i32, i32, i32, i32, ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr } { i32 452, i32 8, i32 20, i32 0, ptr null, ptr @.str.36.ImplClassWithResilientStoredProperty, ptr @_INSTANCE_METHODS_ImplClassWithResilientStoredProperty, ptr null, ptr @_IVARS_ImplClassWithResilientStoredProperty, ptr null, ptr @_PROPERTIES_ImplClassWithResilientStoredProperty, ptr @"$sSo36ImplClassWithResilientStoredPropertyCMU" }, section "__DATA, __objc_data", align 8
 // CHECK: @"OBJC_CLASS_$_ImplClassWithResilientStoredProperty" = global <{ i64, ptr, ptr, ptr, i64 }> <{ i64 ptrtoint (ptr @"OBJC_METACLASS_$_ImplClassWithResilientStoredProperty" to i64), ptr @"OBJC_CLASS_$_NSObject", ptr @_objc_empty_cache, ptr null, i64 ptrtoint (ptr @_DATA_ImplClassWithResilientStoredProperty to i64) }>, section "__DATA,__objc_data, regular", align 8
 
@@ -185,11 +185,15 @@ public func implFunc(_ param: Int32) {}
 @_objcImplementation @_cdecl("implFuncCName")
 public func implFuncCName(_ param: Int32) {}
 
+@implementation @_cdecl("implFuncRenamed_C")
+public func implFuncRenamed_Swift(param: Int32) {}
+
 public func fn(impl: ImplClass, swiftSub: SwiftSubclass) {
   impl.mainMethod(0)
   swiftSub.mainMethod(1)
   implFunc(2)
   implFuncCName(3)
+  implFuncRenamed_Swift(param: 4)
 }
 
 // Swift calling convention -[ImplClass init]
@@ -329,12 +333,12 @@ public func fn(impl: ImplClass, swiftSub: SwiftSubclass) {
 // Swift calling convention SwiftSubclass.deinit (deallocating)
 // CHECK-LABEL: define swiftcc void @"$s19objc_implementation13SwiftSubclassCfD"
 
-// inplFunc(_:)
+// implFunc(_:)
 // CHECK-LABEL: define void @implFunc
 // FIXME: We'd like this to be internal or hidden, not public.
 // CHECK: define swiftcc void @"$s19objc_implementation8implFuncyys5Int32VF"
 
-// inplFuncCName(_:)
+// implFuncCName(_:)
 // CHECK-LABEL: define void @"\01_implFuncAsmName"
 // FIXME: We'd like this to be internal or hidden, not public.
 // CHECK: define swiftcc void @"$s19objc_implementation13implFuncCNameyys5Int32VF"
@@ -346,6 +350,7 @@ public func fn(impl: ImplClass, swiftSub: SwiftSubclass) {
 // CHECK:   [[SEL_2:%[^ ]+]] = load ptr, ptr @"\01L_selector(mainMethod:)", align 8
 // CHECK:   call void @objc_msgSend(ptr {{.*}}, ptr [[SEL_2]], i32 1)
 // CHECK:   call void @implFunc
+// CHECK:   call void @"\01_implFuncAsmName"
 // CHECK:   ret void
 // CHECK: }
 
@@ -357,7 +362,7 @@ public func fn(impl: ImplClass, swiftSub: SwiftSubclass) {
 //
 // This function should directly gather the field sizes and invoke the metadata update.
 // CHECK:         %classFields = alloca [4 x ptr]
-// CHECK:         [[FIELDS_ARRAY:%[0-9]+]] = getelementptr inbounds [4 x ptr], ptr %classFields, i32 0, i32 0
+// CHECK:         [[FIELDS_ARRAY:%[0-9]+]] = getelementptr inbounds{{.*}} [4 x ptr], ptr %classFields, i32 0, i32 0
 // CHECK:         store ptr getelementptr inbounds (ptr, ptr @"$sBi32_WV", i32 8), ptr {{%[0-9]+}}
 // CHECK:         {{%[0-9]+}} = call swiftcc %swift.metadata_response @"$ss6MirrorVSgMa"(i64 63)
 // CHECK:         store ptr {{%[0-9]+}}, ptr {{%[0-9]+}}
diff --git a/test/IRGen/objc_simd.sil b/test/IRGen/objc_simd.sil
index cdbde09c874bf..0fa6d8fecd432 100644
--- a/test/IRGen/objc_simd.sil
+++ b/test/IRGen/objc_simd.sil
@@ -57,15 +57,15 @@ entry(%x : $float3):
 }
 
 // x86_64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
-// i386-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @simd_native_args(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1)
+// i386-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @simd_native_args(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1)
 // aarch64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
 // arm64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
-// armv6-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @simd_native_args(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1)
+// armv6-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @simd_native_args(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1)
 // armv7-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
 // armv7s-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
 // armv7k-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
 // arm64_32-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
-// powerpc64-LABEL: define{{( dllexport)?}}{{( protected)?}} void @simd_native_args(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{.*}}) %1)
+// powerpc64-LABEL: define{{( dllexport)?}}{{( protected)?}} void @simd_native_args(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1)
 // powerpc64le-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
 // s390x-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
 // wasm32-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { float, float, float, float } @simd_native_args(float %0, float %1, float %2, float %3)
diff --git a/test/IRGen/objc_structs.swift b/test/IRGen/objc_structs.swift
index ab047f8476bfe..ebb2ef9c14af8 100644
--- a/test/IRGen/objc_structs.swift
+++ b/test/IRGen/objc_structs.swift
@@ -16,7 +16,7 @@ import gizmo
 // CHECK: define hidden swiftcc { double, double, double, double } @"$s12objc_structs8getFrame{{[_0-9a-zA-Z]*}}F"(ptr %0) {{.*}} {
 func getFrame(_ g: Gizmo) -> NSRect {
   // CHECK: load ptr, ptr @"\01L_selector(frame)"
-  // CHECK: call void @objc_msgSend_stret(ptr noalias nocapture sret({{.*}}) {{.*}}, ptr {{.*}}, ptr {{.*}})
+  // CHECK: call void @objc_msgSend_stret(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{.*}}, ptr {{.*}}, ptr {{.*}})
   return g.frame()
 }
 // CHECK: }
@@ -31,7 +31,7 @@ func setFrame(_ g: Gizmo, frame: NSRect) {
 
 // CHECK: define hidden swiftcc { double, double, double, double } @"$s12objc_structs8makeRect{{[_0-9a-zA-Z]*}}F"(double %0, double %1, double %2, double %3)
 func makeRect(_ a: Double, b: Double, c: Double, d: Double) -> NSRect {
-  // CHECK: call void @NSMakeRect(ptr noalias nocapture sret({{.*}}) {{.*}}, double {{.*}}, double {{.*}}, double {{.*}}, double {{.*}})
+  // CHECK: call void @NSMakeRect(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{.*}}, double {{.*}}, double {{.*}}, double {{.*}}, double {{.*}})
   return NSMakeRect(a,b,c,d)
 }
 // CHECK: }
@@ -45,7 +45,7 @@ func stringFromRect(_ r: NSRect) -> String {
 
 // CHECK: define hidden swiftcc { double, double, double, double } @"$s12objc_structs9insetRect{{[_0-9a-zA-Z]*}}F"(double %0, double %1, double %2, double %3, double %4, double %5)
 func insetRect(_ r: NSRect, x: Double, y: Double) -> NSRect {
-  // CHECK: call void @NSInsetRect(ptr noalias nocapture sret({{.*}}) {{.*}}, ptr byval({{.*}}) align 8 {{.*}}, double {{.*}}, double {{.*}})
+  // CHECK: call void @NSInsetRect(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{.*}}, ptr byval({{.*}}) align 8 {{.*}}, double {{.*}}, double {{.*}})
   return NSInsetRect(r, x, y)
 }
 // CHECK: }
@@ -53,13 +53,13 @@ func insetRect(_ r: NSRect, x: Double, y: Double) -> NSRect {
 // CHECK: define hidden swiftcc { double, double, double, double } @"$s12objc_structs19convertRectFromBase{{[_0-9a-zA-Z]*}}F"(ptr %0, double %1, double %2, double %3, double %4)
 func convertRectFromBase(_ v: NSView, r: NSRect) -> NSRect {
   // CHECK: load ptr, ptr @"\01L_selector(convertRectFromBase:)", align 8
-  // CHECK: call void @objc_msgSend_stret(ptr noalias nocapture sret({{.*}}) {{.*}}, ptr {{.*}}, ptr {{.*}}, ptr byval({{.*}}) align 8 {{.*}})
+  // CHECK: call void @objc_msgSend_stret(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{.*}}, ptr {{.*}}, ptr {{.*}}, ptr byval({{.*}}) align 8 {{.*}})
   return v.convertRect(fromBase: r)
 }
 // CHECK: }
 
 // CHECK: define hidden swiftcc { ptr, ptr, ptr, ptr } @"$s12objc_structs20useStructOfNSStringsySo0deF0VADF"(ptr %0, ptr %1, ptr %2, ptr %3)
-// CHECK:   call void @useStructOfNSStringsInObjC(ptr noalias nocapture sret({{.*}}) {{%.*}}, ptr byval({{.*}}) align 8 {{%.*}})
+// CHECK:   call void @useStructOfNSStringsInObjC(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{%.*}}, ptr byval({{.*}}) align 8 {{%.*}})
 func useStructOfNSStrings(_ s: StructOfNSStrings) -> StructOfNSStrings {
   return useStructOfNSStringsInObjC(s)
 }
diff --git a/test/IRGen/objc_subclass.swift b/test/IRGen/objc_subclass.swift
index 5f89ef8a6f26e..8f2329894301a 100644
--- a/test/IRGen/objc_subclass.swift
+++ b/test/IRGen/objc_subclass.swift
@@ -163,7 +163,7 @@
 // CHECK-64:   [1 x { ptr, ptr, ptr, i32, i32 }] [{ ptr, ptr, ptr, i32, i32 } {
 // CHECK-64:     ptr @"$s13objc_subclass10SwiftGizmoC1xSivpWvd",
 // CHECK-64:     ptr @.str.1.x,
-// CHECK-64:     ptr @.str.0.,
+// CHECK-64:     ptr @.str.1.q,
 // CHECK-64:     i32 3,
 // CHECK-64:     i32 8 }]
 // CHECK-64: }, section "__DATA, {{.*}}", align 8
diff --git a/test/IRGen/objc_super.swift b/test/IRGen/objc_super.swift
index b8a8a2cdea6e0..d36fb769746c9 100644
--- a/test/IRGen/objc_super.swift
+++ b/test/IRGen/objc_super.swift
@@ -40,7 +40,7 @@ class Hoozit : Gizmo {
     // CHECK: [[T0:%.*]] = extractvalue %swift.metadata_response [[TMP]], 0
     // CHECK: store ptr [[T0]], ptr {{.*}}, align 8
     // CHECK: load ptr, ptr @"\01L_selector(frame)"
-    // CHECK: call void @objc_msgSendSuper2_stret(ptr noalias nocapture sret({{.*}}) {{.*}}, ptr {{.*}}, ptr {{.*}})
+    // CHECK: call void @objc_msgSendSuper2_stret(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} {{.*}}, ptr {{.*}}, ptr {{.*}})
     return NSInsetRect(super.frame(), 2.0, 2.0)
   }
   // CHECK: }
@@ -116,7 +116,7 @@ class GenericRuncer<T> : Gizmo {
     // CHECK-NEXT: [[ISA_MASK:%.*]] = load i64, ptr @swift_isaMask, align 8
     // CHECK-NEXT: [[ISA_MASKED:%.*]] = and i64 [[ISA]], [[ISA_MASK]]
     // CHECK-NEXT: [[ISA_PTR:%.*]] = inttoptr i64 [[ISA_MASKED]] to ptr
-    // CHECK:      [[METACLASS_ADDR:%.*]] = getelementptr inbounds %objc_super, ptr %objc_super, i32 0, i32 1
+    // CHECK:      [[METACLASS_ADDR:%.*]] = getelementptr inbounds{{.*}} %objc_super, ptr %objc_super, i32 0, i32 1
     // CHECK-NEXT: store ptr [[ISA_PTR]], ptr [[METACLASS_ADDR]], align 8
     // CHECK-NEXT: [[SELECTOR:%.*]] = load ptr, ptr @"\01L_selector(runce)", align 8
     // CHECK-NEXT: call void @objc_msgSendSuper2(ptr %objc_super, ptr [[SELECTOR]])
diff --git a/test/IRGen/osx-targets.swift b/test/IRGen/osx-targets.swift
index b967650dc2f9c..4a9013b1b9f14 100644
--- a/test/IRGen/osx-targets.swift
+++ b/test/IRGen/osx-targets.swift
@@ -6,7 +6,7 @@
 
 // CHECK: target triple = "{{.*}}-apple-macosx{{[0-9][0-9]}}.
 // CHECK-SPECIFIC-MAC-10-X: target triple = "{{.*}}-apple-macosx10.51.0"
-// CHECK-DARWIN-OVER-11: target triple = "{{.*}}-apple-macosx46.0.0"
+// CHECK-DARWIN-OVER-11: target triple = "{{.*}}-apple-macosx56.0.0"
 
 public func anchor() {}
 anchor()
diff --git a/test/IRGen/pack_metadata_dealloc.swift b/test/IRGen/pack_metadata_dealloc.swift
new file mode 100644
index 0000000000000..1bdb24a4d3369
--- /dev/null
+++ b/test/IRGen/pack_metadata_dealloc.swift
@@ -0,0 +1,30 @@
+// RUN: %target-swift-frontend -emit-ir %s -target %target-swift-5.9-abi-triple | %FileCheck %s
+
+protocol P {
+  associatedtype A
+  var a: A { get }
+}
+
+func f<each T: P>(_ t: repeat each T) -> (repeat (each T).A) {
+  let data = (repeat (each t).a)
+  return data
+}
+
+// CHECK-LABEL: define {{.*}} void @"$s21pack_metadata_dealloc1fy1AQzxQp_txxQpRvzAA1PRzlF"
+// CHECK: [[SPSAVE:%.*]] = call ptr @llvm.stacksave.p0()
+// CHECK: call void @llvm.stackrestore.p0(ptr [[SPSAVE]])
+// CHECK: [[SPSAVE1:%.*]] = call ptr @llvm.stacksave.p0()
+// CHECK: [[SPSAVE2:%.*]] = call ptr @llvm.stacksave.p0()
+// CHECK-NOT: call ptr llvm.stacksave.p0()
+// CHECK:  call void @llvm.stackrestore.p0(ptr [[SPSAVE2]])
+// CHECK:  call void @llvm.stackrestore.p0(ptr [[SPSAVE1]])
+// CHECK:  ret void
+
+struct G<each T> {
+  init(_: repeat each T) {}
+}
+
+func f2<each T: P, each U>(t: repeat each T, u: repeat each U) async -> (repeat G<(each T).A, repeat each U>) {
+  let x = (repeat G((each t).a, repeat each u))
+  return x
+}
\ No newline at end of file
diff --git a/test/IRGen/pack_metadata_marker_inserter_onone.swift b/test/IRGen/pack_metadata_marker_inserter_onone.swift
index 343dd62131a4d..4a7f79365db7f 100644
--- a/test/IRGen/pack_metadata_marker_inserter_onone.swift
+++ b/test/IRGen/pack_metadata_marker_inserter_onone.swift
@@ -23,7 +23,7 @@ public struct S<T> {
 // CHECK-LLVM:         [[G_METADATA_PACK:%[^,]+]] = alloca [1 x ptr]
 // CHECK-LLVM:         call void @llvm.lifetime.start.p0(
 // CHECK-LLVM-SAME:        ptr [[G_METADATA_PACK]])
-// CHECK-LLVM:         [[G_METADATA_PACK_T_SLOT:%[^,]+]] = getelementptr inbounds [1 x ptr], ptr [[G_METADATA_PACK]]
+// CHECK-LLVM:         [[G_METADATA_PACK_T_SLOT:%[^,]+]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[G_METADATA_PACK]]
 // CHECK-LLVM:         store ptr [[T_METADATA]], ptr [[G_METADATA_PACK_T_SLOT]]
 // CHECK-LLVM:         [[G_METADATA_RESPONSE:%[^,]+]] = call swiftcc %swift.metadata_response @"$s35pack_metadata_marker_inserter_onone1GVMa"(
 // CHECK-LLVM-SAME:        ptr [[G_METADATA_PACK]])
@@ -72,7 +72,7 @@ public func consume2S<T>(_: consuming S<T>, _: consuming S<T>) {}
 // CHECK-LLVM:         [[S_METADATA:%[^,]+]] = extractvalue %swift.metadata_response [[S_METADATA_RESPONSE]]
 // CHECK-LLVM:         [[S_VWT_ADDR:%[^,]+]] = getelementptr inbounds ptr, ptr [[S_METADATA]], [[INT]] -1
 // CHECK-LLVM:         [[S_VWT:%[^,]+]] = load ptr, ptr [[S_VWT_ADDR]]
-// CHECK-LLVM:         [[S_SIZE_ADDR:%[^,]+]] = getelementptr inbounds %swift.vwtable, ptr 
+// CHECK-LLVM:         [[S_SIZE_ADDR:%[^,]+]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr 
 //  HECK-LLVM-SAME:        [[S_VWT]]
 // CHECK-LLVM:         [[S_SIZE:%[^,]+]] = load [[INT]], ptr [[S_SIZE_ADDR]]
 // CHECK-LLVM:         [[COPY_1_ADDR:%[^,]+]] = alloca i8, [[INT]] [[S_SIZE]]
@@ -83,7 +83,7 @@ public func consume2S<T>(_: consuming S<T>, _: consuming S<T>) {}
 // CHECK-LLVM-SAME:        ptr [[COPY_2_ADDR]])
 // CHECK-LLVM:         call void @llvm.lifetime.start.p0(
 // CHECK-LLVM-SAME:        ptr [[G_METADATA_PACK]])
-// CHECK-LLVM:         [[G_METADATA_PACK_T_SLOT:%[^,]+]] = getelementptr inbounds [1 x ptr], ptr [[G_METADATA_PACK]]
+// CHECK-LLVM:         [[G_METADATA_PACK_T_SLOT:%[^,]+]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[G_METADATA_PACK]]
 // CHECK-LLVM:         store ptr [[T_METADATA]], ptr [[G_METADATA_PACK_T_SLOT]]
 // CHECK-LLVM:         [[G_METADATA_RESPONSE:%[^,]+]] = call swiftcc %swift.metadata_response @"$s35pack_metadata_marker_inserter_onone1GVMa"(
 // CHECK-LLVM-SAME:        ptr [[G_METADATA_PACK]])
diff --git a/test/IRGen/package_bypass_resilience_class.swift b/test/IRGen/package_bypass_resilience_class.swift
index 9496cfe063e82..0df131fdd0a76 100644
--- a/test/IRGen/package_bypass_resilience_class.swift
+++ b/test/IRGen/package_bypass_resilience_class.swift
@@ -46,7 +46,7 @@ final public class Pub {
   // method lookup function for Core.Pub
   // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc ptr @"$s4Core3PubCMu"(ptr %0, ptr %1)
 
-  // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc ptr @"$s4Core3PubCfd"(ptr readnone returned swiftself %0)
+  // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc ptr @"$s4Core3PubCfd"(ptr readnone returned swiftself{{.*}} %0)
   // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc void @"$s4Core3PubCfD"(ptr swiftself %0)
 }
 
@@ -97,7 +97,7 @@ package class Foo {
   // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc { ptr, ptr } @"$s4Core3FooC02myB0AA3PubCSgvMTj"
 
   // Core.Foo.deinit
-  // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc ptr @"$s4Core3FooCfd"(ptr readonly returned swiftself %0)
+  // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc ptr @"$s4Core3FooCfd"(ptr readonly returned swiftself{{.*}} %0)
 
   // Core.Foo.__deallocating_deinit
   // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc void @"$s4Core3FooCfD"(ptr swiftself %0)
@@ -119,7 +119,7 @@ final package class Bar {
   // method lookup function for Core.Bar
   // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc ptr @"$s4Core3BarCMu"(ptr %0, ptr %1)
 
-  // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc ptr @"$s4Core3BarCfd"(ptr readonly returned swiftself %0)
+  // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc ptr @"$s4Core3BarCfd"(ptr readonly returned swiftself{{.*}} %0)
   // CHECK-COMMON-DAG: define {{(dllexport |protected )?}}swiftcc void @"$s4Core3BarCfD"(ptr swiftself %0)
 
   package var myBar: Pub?
diff --git a/test/IRGen/package_resilience.swift b/test/IRGen/package_resilience.swift
index ab089270ecd9c..c00033a5b2081 100644
--- a/test/IRGen/package_resilience.swift
+++ b/test/IRGen/package_resilience.swift
@@ -172,22 +172,22 @@ package class ClassWithResilientThenEmpty {
 // ClassWithResilientProperty.color getter
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @"$s18package_resilience26ClassWithResilientPropertyC5colors5Int32Vvg"(ptr swiftself %0)
-// CHECK:      [[FIELD_ADDR:%.*]] = getelementptr inbounds %T18package_resilience26ClassWithResilientPropertyC, ptr %0,
-// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK:      [[FIELD_ADDR:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience26ClassWithResilientPropertyC, ptr %0,
+// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_VALUE:%.*]] = load i32, ptr [[FIELD_PAYLOAD]]
 // CHECK:      ret i32 [[FIELD_VALUE]]
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @"$s18package_resilience33ClassWithResilientlySizedPropertyC5colors5Int32Vvg"(ptr swiftself %0)
-// CHECK:      [[FIELD_ADDR:%.*]] = getelementptr inbounds %T18package_resilience33ClassWithResilientlySizedPropertyC, ptr %0,
-// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK:      [[FIELD_ADDR:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience33ClassWithResilientlySizedPropertyC, ptr %0,
+// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_VALUE:%.*]] = load i32, ptr [[FIELD_PAYLOAD]]
 // CHECK:      ret i32 [[FIELD_VALUE]]
 
 // ClassWithIndirectResilientEnum.color getter
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @"$s18package_resilience30ClassWithIndirectResilientEnumC5colors5Int32Vvg"(ptr swiftself %0)
-// CHECK:      [[FIELD_PTR:%.*]] = getelementptr inbounds %T18package_resilience30ClassWithIndirectResilientEnumC, ptr %0, i32 0, i32 2
-// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[FIELD_PTR]], i32 0, i32 0
+// CHECK:      [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience30ClassWithIndirectResilientEnumC, ptr %0, i32 0, i32 2
+// CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[FIELD_PTR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_VALUE:%.*]] = load i32, ptr [[FIELD_PAYLOAD]]
 // CHECK-NEXT: ret i32 [[FIELD_VALUE]]
 
@@ -197,8 +197,8 @@ package class ClassWithResilientThenEmpty {
 // MyResilientChild.field getter
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i32 @"$s18package_resilience16MyResilientChildC5fields5Int32Vvg"(ptr swiftself %0)
-// CHECK:      [[FIELD_ADDR:%.*]] = getelementptr inbounds %T18package_resilience16MyResilientChildC, ptr %0, i32 0, i32 2
-// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK:      [[FIELD_ADDR:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience16MyResilientChildC, ptr %0, i32 0, i32 2
+// CHECK-NEXT: [[PAYLOAD_ADDR:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[FIELD_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[RESULT:%.*]] = load i32, ptr [[PAYLOAD_ADDR]]
 // CHECK:      ret i32 [[RESULT]]
 
@@ -232,14 +232,14 @@ public func memoryLayoutDotAlignmentWithResilientStruct() -> Int {
 
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void  @"$s18package_resilience31constructResilientEnumNoPayload14resilient_enum6MediumOyF"
 package func constructResilientEnumNoPayload() -> Medium {
-  // CHECK: [[FIELD_PTR:%.*]] = getelementptr inbounds %T14resilient_enum6MediumO, ptr %0, i32 0, i32 1
+  // CHECK: [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %T14resilient_enum6MediumO, ptr %0, i32 0, i32 1
   // CHECK: ret void
   return Medium.Paper
 }
 
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s18package_resilience39constructExhaustiveWithResilientMembers14resilient_enum11SimpleShapeOyF"
 package func constructExhaustiveWithResilientMembers() -> SimpleShape {
-  // CHECK: [[FIELD_PTR:%.*]] = getelementptr inbounds %T14resilient_enum11SimpleShapeO, ptr %0, i32 0, i32 1
+  // CHECK: [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %T14resilient_enum11SimpleShapeO, ptr %0, i32 0, i32 1
   // CHECK: ret void
   return .KleinBottle
 }
diff --git a/test/IRGen/package_resilient_as_public_by_default.swift b/test/IRGen/package_resilient_as_public_by_default.swift
index dedf6470da569..ac3dce2659aee 100644
--- a/test/IRGen/package_resilient_as_public_by_default.swift
+++ b/test/IRGen/package_resilient_as_public_by_default.swift
@@ -87,7 +87,7 @@ public class PublicClassWithPbProperties {
 // CHECK: define{{.*}} swiftcc {{.*}} @"$s18package_resilience27PublicClassWithPbPropertiesC5colors5Int32Vvg"(ptr swiftself %0)
 // CHECK:       [[OFFSET:%.*]] = load {{i32|i64}}, ptr @"$s18package_resilience27PublicClassWithPbPropertiesC5colors5Int32VvpWvd"
 // CHECK-NEXT:  [[PTR:%.*]] = getelementptr inbounds i8, ptr {{.*}}, {{i32|i64}} [[OFFSET]]
-// CHECK-NEXT:  [[VALUE:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[PTR]]
+// CHECK-NEXT:  [[VALUE:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[PTR]]
 // CHECK-NEXT:  [[RET:%.*]] = load {{i32|i64}}, ptr [[VALUE]]
 // CHECK-NEXT:  ret {{i32|i64}} [[RET]]
 
@@ -126,7 +126,7 @@ package class PkgClassWithPublicProperties {
 // CHECK: define{{.*}} swiftcc {{.*}} @"$s18package_resilience28PkgClassWithPublicPropertiesC5colors5Int32Vvg"(ptr swiftself %0)
 // CHECK:       [[OFFSET:%.*]] = load {{i32|i64}}, ptr @"$s18package_resilience28PkgClassWithPublicPropertiesC5colors5Int32VvpWvd"
 // CHECK-NEXT:  [[PTR:%.*]] = getelementptr inbounds i8, ptr {{.*}}, {{i32|i64}} [[OFFSET]]
-// CHECK-NEXT:  [[VALUE:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[PTR]]
+// CHECK-NEXT:  [[VALUE:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[PTR]]
 // CHECK-NEXT:  [[RET:%.*]] = load {{i32|i64}}, ptr [[VALUE]]
 // CHECK-NEXT:  ret {{i32|i64}} [[RET]]
 
@@ -162,7 +162,7 @@ package class PkgWithPackageProperties {
 // CHECK: define{{.*}} swiftcc {{.*}} @"$s18package_resilience24PkgWithPackagePropertiesC5colors5Int32Vvg"(ptr swiftself %0)
 // CHECK:       [[OFFSET:%.*]] = load {{i32|i64}}, ptr @"$s18package_resilience24PkgWithPackagePropertiesC5colors5Int32VvpWvd"
 // CHECK-NEXT:  [[PTR:%.*]] = getelementptr inbounds i8, ptr {{.*}}, {{i32|i64}} [[OFFSET]]
-// CHECK-NEXT:  [[VALUE:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[PTR]]
+// CHECK-NEXT:  [[VALUE:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[PTR]]
 // CHECK-NEXT:  [[RET:%.*]] = load {{i32|i64}}, ptr [[VALUE]]
 // CHECK-NEXT:  ret {{i32|i64}} [[RET]]
 
@@ -182,12 +182,12 @@ public class PublicClassWithFrozenPbProperties {
 // PublicClassWithFrozenPbProperties.p getter
 
 // CHECK: define{{.*}} swiftcc { {{i32|i64}}, {{i32|i64}} } @"$s18package_resilience33PublicClassWithFrozenPbPropertiesC1p16resilient_struct0fC5PointVvg"(ptr swiftself %0)
-// CHECK:      [[T1:%.*]] = getelementptr inbounds %T18package_resilience33PublicClassWithFrozenPbPropertiesC, ptr {{.*}}
-// CHECK-NEXT: [[X:%.*]] = getelementptr inbounds %T16resilient_struct17FrozenPublicPointV, ptr [[T1]]
-// CHECK-NEXT: [[XVAL:%.*]] = getelementptr inbounds %TSi, ptr [[X]]
+// CHECK:      [[T1:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience33PublicClassWithFrozenPbPropertiesC, ptr {{.*}}
+// CHECK-NEXT: [[X:%.*]] = getelementptr inbounds{{.*}} %T16resilient_struct17FrozenPublicPointV, ptr [[T1]]
+// CHECK-NEXT: [[XVAL:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[X]]
 // CHECK-NEXT: [[T2:%.*]] = load {{i32|i64}}, ptr [[XVAL]]
-// CHECK-NEXT: [[Y:%.*]] = getelementptr inbounds %T16resilient_struct17FrozenPublicPointV, ptr [[T1]]
-// CHECK-NEXT: [[YVAL:%.*]] = getelementptr inbounds %TSi, ptr [[Y]]
+// CHECK-NEXT: [[Y:%.*]] = getelementptr inbounds{{.*}} %T16resilient_struct17FrozenPublicPointV, ptr [[T1]]
+// CHECK-NEXT: [[YVAL:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[Y]]
 // CHECK-NEXT: [[T3:%.*]] = load {{i32|i64}}, ptr [[YVAL]]
 // CHECK-NEXT: [[T4:%.*]] = insertvalue {{.*}} undef, {{i32|i64}} [[T2]], 0
 // CHECK-NEXT: [[T5:%.*]] = insertvalue {{.*}} [[T4]], {{i32|i64}} [[T3]], 1
@@ -197,8 +197,8 @@ public class PublicClassWithFrozenPbProperties {
 // PublicClassWithFrozenPbProperties.color getter
 
 // CHECK: define{{.*}} swiftcc {{i32|64}} @"$s18package_resilience33PublicClassWithFrozenPbPropertiesC5colors5Int32Vvg"(ptr swiftself %0)
-// CHECK:      [[T1:%.*]] = getelementptr inbounds %T18package_resilience33PublicClassWithFrozenPbPropertiesC, ptr {{.*}}
-// CHECK-NEXT: [[VAL:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[T1]]
+// CHECK:      [[T1:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience33PublicClassWithFrozenPbPropertiesC, ptr {{.*}}
+// CHECK-NEXT: [[VAL:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[T1]]
 // CHECK-NEXT: [[T2:%.*]] = load {{i32|i64}}, ptr [[VAL]]
 // CHECK-NEXT: ret {{i32|i64}} [[T2]]
 
@@ -219,12 +219,12 @@ package class PkgClassWithFrozenPublicProperties {
 // PkgClassWithFrozenPublicProperties.p getter
 
 // CHECK: define{{.*}} swiftcc { i64, i64 } @"$s18package_resilience34PkgClassWithFrozenPublicPropertiesC1p16resilient_struct0fG5PointVvg"(ptr swiftself %0)
-// CHECK:      [[T1:%.*]] = getelementptr inbounds %T18package_resilience34PkgClassWithFrozenPublicPropertiesC, ptr {{.*}}
-// CHECK-NEXT: [[X:%.*]] = getelementptr inbounds %T16resilient_struct17FrozenPublicPointV, ptr [[T1]]
-// CHECK-NEXT: [[XVAL:%.*]] = getelementptr inbounds %TSi, ptr [[X]]
+// CHECK:      [[T1:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience34PkgClassWithFrozenPublicPropertiesC, ptr {{.*}}
+// CHECK-NEXT: [[X:%.*]] = getelementptr inbounds{{.*}} %T16resilient_struct17FrozenPublicPointV, ptr [[T1]]
+// CHECK-NEXT: [[XVAL:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[X]]
 // CHECK-NEXT: [[T2:%.*]] = load {{i32|i64}}, ptr [[XVAL]]
-// CHECK-NEXT: [[Y:%.*]] = getelementptr inbounds %T16resilient_struct17FrozenPublicPointV, ptr [[T1]]
-// CHECK-NEXT: [[YVAL:%.*]] = getelementptr inbounds %TSi, ptr [[Y]]
+// CHECK-NEXT: [[Y:%.*]] = getelementptr inbounds{{.*}} %T16resilient_struct17FrozenPublicPointV, ptr [[T1]]
+// CHECK-NEXT: [[YVAL:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[Y]]
 // CHECK-NEXT: [[T3:%.*]] = load {{i32|i64}}, ptr [[YVAL]]
 // CHECK-NEXT: [[T4:%.*]] = insertvalue { i64, i64 } undef, i64 [[T2]], 0
 // CHECK-NEXT: [[T5:%.*]] = insertvalue { i64, i64 } %4, i64 [[T3]], 1
@@ -233,8 +233,8 @@ package class PkgClassWithFrozenPublicProperties {
 // PkgClassWithFrozenPublicProperties.color getter
 
 // CHECK: define{{.*}} swiftcc {{i32|64}} @"$s18package_resilience34PkgClassWithFrozenPublicPropertiesC5colors5Int32Vvg"(ptr swiftself %0) #0 {
-// CHECK:      [[T1:%.*]] = getelementptr inbounds %T18package_resilience34PkgClassWithFrozenPublicPropertiesC, ptr {{.*}}
-// CHECK-NEXT: [[VAL:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[T1]]
+// CHECK:      [[T1:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience34PkgClassWithFrozenPublicPropertiesC, ptr {{.*}}
+// CHECK-NEXT: [[VAL:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[T1]]
 // CHECK-NEXT: [[T2:%.*]] = load {{i32|i64}}, ptr [[VAL]]
 // CHECK-NEXT: ret {{i32|i64}} [[T2]]
 
@@ -269,7 +269,7 @@ public class PublicClassWithEnumIndirectCases {
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc {{.*}} @"$s18package_resilience32PublicClassWithEnumIndirectCasesC5colors5Int32Vvg"(ptr swiftself %0)
 // CHECK:      [[OFFSET:%.*]] = load {{i32|i64}}, ptr @"$s18package_resilience32PublicClassWithEnumIndirectCasesC5colors5Int32VvpWvd",
 // CHECK-NEXT: [[PTR:%.*]] = getelementptr inbounds i8, ptr {{.*}}, {{i32|i64}} [[OFFSET]]
-// CHECK-NEXT: [[VALUE:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[PTR]]
+// CHECK-NEXT: [[VALUE:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[PTR]]
 // CHECK-NEXT: [[RET:%.*]] = load {{i32|i64}}, ptr [[VALUE]]
 // CHECK-NEXT: ret {{i32|i64}} [[RET]]
 
@@ -302,7 +302,7 @@ package class PkgClassWithEnumIndirectCases {
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc {{i32|64}} @"$s18package_resilience29PkgClassWithEnumIndirectCasesC5colors5Int32Vvg"(ptr swiftself %0)
 // CHECK:      [[OFFSET:%.*]] = load {{i32|i64}}, ptr @"$s18package_resilience29PkgClassWithEnumIndirectCasesC5colors5Int32VvpWvd",
 // CHECK-NEXT: [[PTR:%.*]] = getelementptr inbounds i8, ptr {{.*}}, {{i32|i64}} [[OFFSET]]
-// CHECK-NEXT: [[VALUE:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[PTR]]
+// CHECK-NEXT: [[VALUE:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[PTR]]
 // CHECK-NEXT: [[RET:%.*]] = load {{i32|i64}}, ptr [[VALUE]]
 // CHECK-NEXT: ret {{i32|i64}} [[RET]]
 
@@ -339,8 +339,8 @@ public class PublicClassConcreteChild : PublicClassGenericParent<Int> {
 // PublicClassConcreteChild.x getter
 
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc {{.*}} @"$s18package_resilience24PublicClassConcreteChildC1xSivg"(ptr swiftself %0)
-// CHECK:      [[PTR:%.*]] = getelementptr inbounds %T18package_resilience24PublicClassConcreteChildC, ptr {{.*}}
-// CHECK-NEXT: [[VAL:%.*]] = getelementptr inbounds %TSi, ptr [[PTR]]
+// CHECK:      [[PTR:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience24PublicClassConcreteChildC, ptr {{.*}}
+// CHECK-NEXT: [[VAL:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[PTR]]
 // CHECK-NEXT: [[RET:%.*]] = load {{i32|i64}}, ptr [[VAL]]
 // CHECK-NEXT: ret {{i32|i64}} [[RET]]
 
@@ -379,8 +379,8 @@ package class PkgClassConcreteChild : PkgClassGenericParent<Int> {
 // PkgClassConcreteChild.x getter
 
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc {{.*}} @"$s18package_resilience21PkgClassConcreteChildC1xSivg"(ptr swiftself %0)
-// CHECK:      [[PTR:%.*]] = getelementptr inbounds %T18package_resilience21PkgClassConcreteChildC, ptr {{.*}}
-// CHECK-NEXT: [[VAL:%.*]] = getelementptr inbounds %TSi, ptr [[PTR]]
+// CHECK:      [[PTR:%.*]] = getelementptr inbounds{{.*}} %T18package_resilience21PkgClassConcreteChildC, ptr {{.*}}
+// CHECK-NEXT: [[VAL:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[PTR]]
 // CHECK-NEXT: [[RET:%.*]] = load {{i32|i64}}, ptr [[VAL]]
 // CHECK-NEXT: ret {{i32|i64}} [[RET]]
 
@@ -470,7 +470,7 @@ package class PkgClassWithResilientThenEmpty {
 // CHECK: define{{.*}} swiftcc {{.*}} @"$s18package_resilience35memoryLayoutDotSizeWithPublicStructSiyF"()
 public func memoryLayoutDotSizeWithPublicStruct() -> Int {
   // CHECK: [[FIELD_VALUE:%.*]] = load ptr, ptr {{.*}},
-  // CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[FIELD_VALUE]],
+  // CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[FIELD_VALUE]],
   // CHECK-NEXT: [[SIZE:%.*]] = load {{i32|i64}}, ptr [[FIELD_PTR]],
   // CHECK-NEXT: ret {{i32|i64}} [[SIZE]]
   return MemoryLayout<PublicSize>.size
@@ -479,7 +479,7 @@ public func memoryLayoutDotSizeWithPublicStruct() -> Int {
 // CHECK: define{{.*}} swiftcc {{.*}} @"$s18package_resilience32memoryLayoutDotSizeWithPkgStructSiyF"()
 package func memoryLayoutDotSizeWithPkgStruct() -> Int {
 // CHECK: [[FIELD_VALUE:%.*]] = load ptr, ptr {{.*}},
-// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[FIELD_VALUE]],
+// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[FIELD_VALUE]],
 // CHECK-NEXT: [[SIZE:%.*]] = load {{i32|i64}}, ptr [[FIELD_PTR]],
 // CHECK-NEXT: ret {{i32|i64}} [[SIZE]]
   return MemoryLayout<Size>.size
@@ -495,7 +495,7 @@ public func memoryLayoutDotSizeWithFrozenPublicStruct() -> Int {
 // CHECK: define{{.*}} swiftcc {{.*}} @"$s18package_resilience37memoryLayoutDotStrideWithPublicStructSiyF"()
 public func memoryLayoutDotStrideWithPublicStruct() -> Int {
 // CHECK: [[FIELD_VALUE:%.*]] = load ptr, ptr {{.*}},
-// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[FIELD_VALUE]],
+// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[FIELD_VALUE]],
 // CHECK-NEXT: [[STRIDE:%.*]] = load {{i32|i64}}, ptr [[FIELD_PTR]],
 // CHECK-NEXT: ret {{i32|i64}} [[STRIDE]]
   return MemoryLayout<PublicSize>.stride
@@ -504,7 +504,7 @@ public func memoryLayoutDotStrideWithPublicStruct() -> Int {
 // CHECK: define{{.*}} swiftcc {{.*}} @"$s18package_resilience34memoryLayoutDotStrideWithPkgStructSiyF"()
 package func memoryLayoutDotStrideWithPkgStruct() -> Int {
 // CHECK: [[FIELD_VALUE:%.*]] = load ptr, ptr {{.*}},
-// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[FIELD_VALUE]],
+// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[FIELD_VALUE]],
 // CHECK-NEXT: [[STRIDE:%.*]] = load {{i32|i64}}, ptr [[FIELD_PTR]],
 // CHECK-NEXT: ret {{i32|i64}} [[STRIDE]]
   return MemoryLayout<Size>.stride
@@ -520,7 +520,7 @@ public func memoryLayoutDotStrideWithFrozenPublicStruct() -> Int {
 // CHECK: define{{.*}} swiftcc {{.*}} @"$s18package_resilience40memoryLayoutDotAlignmentWithPublicStructSiyF"()
 public func memoryLayoutDotAlignmentWithPublicStruct() -> Int {
 // CHECK: [[FIELD_VALUE:%.*]] = load ptr, ptr {{.*}},
-// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[FIELD_VALUE]],
+// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[FIELD_VALUE]],
 // CHECK-NEXT:  [[FIELD_FLAGS:%.*]] = load {{i32|i64}}, ptr [[FIELD_PTR]],
 // CHECK-NEXT:  [[FIELD_ADDR:%.*]] = zext {{i32|i64}} [[FIELD_FLAGS]] to {{i32|i64}}
 // CHECK-NEXT:  [[FIELD_MASK:%.*]] = and {{i32|i64}} [[FIELD_ADDR]]
@@ -532,7 +532,7 @@ public func memoryLayoutDotAlignmentWithPublicStruct() -> Int {
 // CHECK: define{{.*}} swiftcc {{.*}} @"$s18package_resilience43memoryLayoutDotAlignmentWithResilientStructSiyF"()
 package func memoryLayoutDotAlignmentWithResilientStruct() -> Int {
 // CHECK: [[FIELD_VALUE:%.*]] = load ptr, ptr {{.*}},
-// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[FIELD_VALUE]],
+// CHECK-NEXT: [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[FIELD_VALUE]],
 // CHECK-NEXT:  [[FIELD_FLAGS:%.*]] = load {{i32|i64}}, ptr [[FIELD_PTR]],
 // CHECK-NEXT:  [[FIELD_ADDR:%.*]] = zext {{i32|i64}} [[FIELD_FLAGS]] to {{i32|i64}}
 // CHECK-NEXT:  [[FIELD_MASK:%.*]] = and {{i32|i64}} [[FIELD_ADDR]]
diff --git a/test/IRGen/partial_apply.sil b/test/IRGen/partial_apply.sil
index 6ebfac8e03a82..8f4df181fe7e1 100644
--- a/test/IRGen/partial_apply.sil
+++ b/test/IRGen/partial_apply.sil
@@ -53,9 +53,9 @@ entry(%a : $SwiftClass):
 // CHECK: define{{.*}} swiftcc void @partial_apply_two_classes_on_stack(ptr %0, ptr %1)
 // CHECK: entry:
 // CHECK:   [[CTX:%.*]] = alloca i8, i64 32, align 16
-// CHECK:   [[CAPTURE1:%.*]] = getelementptr inbounds <{ %swift.refcounted, ptr, ptr }>, ptr [[CTX]], i32 0, i32 1
+// CHECK:   [[CAPTURE1:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr, ptr }>, ptr [[CTX]], i32 0, i32 1
 // CHECK:   store ptr %0, ptr [[CAPTURE1]], align 8
-// CHECK:   [[CAPTURE2:%.*]] = getelementptr inbounds <{ %swift.refcounted, ptr, ptr }>, ptr [[CTX]], i32 0, i32 2
+// CHECK:   [[CAPTURE2:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr, ptr }>, ptr [[CTX]], i32 0, i32 2
 // CHECK:   store ptr %1, ptr [[CAPTURE2]], align 8
 // CHECK:   call swiftcc void @use_closure(ptr @"$s34partially_applyable_to_two_classesTA", ptr [[CTX]])
 // CHECK:   call void @swift_release(ptr %0)
@@ -135,7 +135,7 @@ bb0(%x : $SwiftClass):
 
 sil public_external @indirect_guaranteed_captured_class_param : $@convention(thin) (Int, @in_guaranteed SwiftClass) -> Int
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_indirect_guaranteed_class_param(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_indirect_guaranteed_class_param(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 // CHECK-NOT:     {{retain|release}}
 // CHECK:         [[X:%.*]] = load ptr, ptr %0
 // CHECK-NOT:     {{retain|release}}
@@ -148,7 +148,7 @@ sil public_external @indirect_guaranteed_captured_class_param : $@convention(thi
 // CHECK-NOT:     load
 // CHECK-NOT:     retain
 // CHECK-NOT:     release
-// CHECK:         [[RESULT:%.*]] = call swiftcc i64 @indirect_guaranteed_captured_class_param(i64 %0, ptr noalias nocapture dereferenceable({{.*}}) [[X_TMP]]
+// CHECK:         [[RESULT:%.*]] = call swiftcc i64 @indirect_guaranteed_captured_class_param(i64 %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) [[X_TMP]]
 // CHECK-NOT:     retain
 // CHECK:         call void @swift_release(ptr %1)
 // CHECK:         ret i64 [[RESULT]]
@@ -162,7 +162,7 @@ bb0(%x : $*SwiftClass):
 
 sil public_external @indirect_consumed_captured_class_param : $@convention(thin) (Int, @in SwiftClass) -> Int
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_indirect_consumed_class_param(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_indirect_consumed_class_param(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 // CHECK-NOT:     {{retain|release}}
 // CHECK:         [[CONTEXT_OBJ:%.*]] = load ptr, ptr %0
 // CHECK-NOT:     {{retain|release}}
@@ -175,7 +175,7 @@ sil public_external @indirect_consumed_captured_class_param : $@convention(thin)
 // CHECK-NOT:     load
 // CHECK-NOT:     retain
 // CHECK-NOT:     release
-// CHECK:         [[RESULT:%.*]] = call swiftcc i64 @indirect_consumed_captured_class_param(i64 %0, ptr noalias nocapture dereferenceable({{.*}}) [[X_TMP]])
+// CHECK:         [[RESULT:%.*]] = call swiftcc i64 @indirect_consumed_captured_class_param(i64 %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) [[X_TMP]])
 // CHECK-NOT:     retain
 // CHECK-NOT:     release
 // CHECK:         ret i64 [[RESULT]]
@@ -199,9 +199,9 @@ sil public_external @guaranteed_captured_class_pair_param : $@convention(thin) (
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_guaranteed_class_pair_param(ptr %0, ptr %1)
 // CHECK:         [[CONTEXT_OBJ:%.*]] = call noalias ptr @swift_allocObject
 // CHECK:         [[PAIR_ADDR:%.*]] = getelementptr
-// CHECK-NEXT:    [[X_ADDR:%.*]] = getelementptr inbounds %T13partial_apply14SwiftClassPairV, ptr [[PAIR_ADDR]], i32 0, i32 0
+// CHECK-NEXT:    [[X_ADDR:%.*]] = getelementptr inbounds{{.*}} %T13partial_apply14SwiftClassPairV, ptr [[PAIR_ADDR]], i32 0, i32 0
 // CHECK-NEXT:    store ptr %0, ptr [[X_ADDR]], align
-// CHECK-NEXT:    [[Y_ADDR:%.*]] = getelementptr inbounds %T13partial_apply14SwiftClassPairV, ptr [[PAIR_ADDR]], i32 0, i32 1
+// CHECK-NEXT:    [[Y_ADDR:%.*]] = getelementptr inbounds{{.*}} %T13partial_apply14SwiftClassPairV, ptr [[PAIR_ADDR]], i32 0, i32 1
 // CHECK-NEXT:    store ptr %1, ptr [[Y_ADDR]], align
 // CHECK-NOT:     {{retain|release}}
 // CHECK:         [[T0:%.*]] = insertvalue {{.*}} [[PARTIAL_APPLY_FORWARDER:@"\$s[A-Za-z0-9_]+TA"]], {{.*}} [[CONTEXT_OBJ]]
@@ -209,9 +209,9 @@ sil public_external @guaranteed_captured_class_pair_param : $@convention(thin) (
 
 // CHECK:       define internal swiftcc i64 [[PARTIAL_APPLY_FORWARDER]]
 // CHECK:         [[PAIR_ADDR:%.*]] = getelementptr
-// CHECK-NEXT:    [[X_ADDR:%.*]] = getelementptr inbounds %T13partial_apply14SwiftClassPairV, ptr [[PAIR_ADDR]], i32 0, i32 0
+// CHECK-NEXT:    [[X_ADDR:%.*]] = getelementptr inbounds{{.*}} %T13partial_apply14SwiftClassPairV, ptr [[PAIR_ADDR]], i32 0, i32 0
 // CHECK-NEXT:    [[X:%.*]] = load ptr, ptr [[X_ADDR]], align
-// CHECK-NEXT:    [[Y_ADDR:%.*]] = getelementptr inbounds %T13partial_apply14SwiftClassPairV, ptr [[PAIR_ADDR]], i32 0, i32 1
+// CHECK-NEXT:    [[Y_ADDR:%.*]] = getelementptr inbounds{{.*}} %T13partial_apply14SwiftClassPairV, ptr [[PAIR_ADDR]], i32 0, i32 1
 // CHECK-NEXT:    [[Y:%.*]] = load ptr, ptr [[Y_ADDR]], align
 // CHECK-NOT:     retain
 // CHECK:         [[RESULT:%.*]] = call swiftcc i64 @guaranteed_captured_class_pair_param(i64 %0, ptr [[X]], ptr [[Y]])
@@ -227,7 +227,7 @@ bb0(%x : $SwiftClassPair):
 
 sil public_external @indirect_guaranteed_captured_class_pair_param : $@convention(thin) (Int, @in_guaranteed SwiftClassPair) -> Int
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_indirect_guaranteed_class_pair_param(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_indirect_guaranteed_class_pair_param(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 // CHECK:         [[CONTEXT_OBJ:%.*]] = call noalias ptr @swift_allocObject
 // CHECK-NOT:     {{retain|release}}
 // CHECK:         [[T0:%.*]] = insertvalue {{.*}} [[PARTIAL_APPLY_FORWARDER:@"\$s[A-Za-z0-9_]+TA"]], {{.*}} [[CONTEXT_OBJ]]
@@ -237,7 +237,7 @@ sil public_external @indirect_guaranteed_captured_class_pair_param : $@conventio
 // CHECK:         [[PAIR_ADDR:%.*]] = getelementptr
 // CHECK-NOT:     load
 // CHECK-NOT:     retain
-// CHECK:         [[RESULT:%.*]] = call swiftcc i64 @indirect_guaranteed_captured_class_pair_param(i64 %0, ptr noalias nocapture dereferenceable({{.*}}) [[PAIR_ADDR]])
+// CHECK:         [[RESULT:%.*]] = call swiftcc i64 @indirect_guaranteed_captured_class_pair_param(i64 %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) [[PAIR_ADDR]])
 // CHECK:         release{{.*}}%1)
 // CHECK:         ret i64 [[RESULT]]
 
@@ -250,7 +250,7 @@ bb0(%x : $*SwiftClassPair):
 
 sil public_external @indirect_consumed_captured_class_pair_param : $@convention(thin) (Int, @in SwiftClassPair) -> Int
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_indirect_consumed_class_pair_param(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_indirect_consumed_class_pair_param(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 // CHECK:         [[CONTEXT_OBJ:%.*]] = call noalias ptr @swift_allocObject
 // CHECK-NOT:     {{retain|release}}
 // CHECK:         [[T0:%.*]] = insertvalue {{.*}} [[PARTIAL_APPLY_FORWARDER:@"\$s[A-Za-z0-9_]+TA"]], {{.*}} [[CONTEXT_OBJ]]
@@ -260,7 +260,7 @@ sil public_external @indirect_consumed_captured_class_pair_param : $@convention(
 // CHECK:         [[X_TMP:%.*]] = alloca
 // CHECK:         call ptr @"$s13partial_apply14SwiftClassPairVWOc"
 // CHECK:         release{{.*}}%1)
-// CHECK:         [[RESULT:%.*]] = call swiftcc i64 @indirect_consumed_captured_class_pair_param(i64 %0, ptr noalias nocapture dereferenceable({{.*}}) [[X_TMP]])
+// CHECK:         [[RESULT:%.*]] = call swiftcc i64 @indirect_consumed_captured_class_pair_param(i64 %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) [[X_TMP]])
 // CHECK:         ret i64 [[RESULT]]
 
 sil @partial_apply_indirect_consumed_class_pair_param : $@convention(thin) (@in SwiftClassPair) -> @callee_owned (Int) -> Int {
@@ -276,7 +276,7 @@ sil public_external @captured_fixed_and_dependent_params : $@convention(thin) <A
 // -- Round the base offset for the T field up to T's alignment.
 // CHECK:         [[T_VWTABLE_ADDR:%.*]] = getelementptr {{.*}} %T, [[WORD:i[0-9]+]] -1
 // CHECK:         [[T_VWTABLE:%.*]] = load {{.*}} [[T_VWTABLE_ADDR]]
-// CHECK:         [[T_FLAGS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[T_VWTABLE]], i32 0, i32 10
+// CHECK:         [[T_FLAGS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[T_VWTABLE]], i32 0, i32 10
 // CHECK:         [[T_FLAGS:%.*]] = load i32, ptr [[T_FLAGS_ADDR]]
 // CHECK-64:      [[T0:%.*]] = zext i32 [[T_FLAGS]] to i64
 // CHECK-64:      [[T_ALIGN_MASK:%.*]] = and i64 [[T0]], 255
@@ -291,7 +291,7 @@ sil public_external @captured_fixed_and_dependent_params : $@convention(thin) <A
 // CHECK:         [[T_OFFSET:%.*]] = and [[WORD]] [[T_UP_TO_ALIGN_1]], [[T_ALIGN_MASK_NOT]]
 
 // -- Add the size of T to start the Int field.
-// CHECK:         [[T_SIZE_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[T_VWTABLE]], i32 0, i32 8
+// CHECK:         [[T_SIZE_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[T_VWTABLE]], i32 0, i32 8
 // CHECK:         [[T_SIZE:%.*]] = load [[WORD]], ptr [[T_SIZE_ADDR]]
 // CHECK:         [[T_END:%.*]] = add [[WORD]] [[T_OFFSET]], [[T_SIZE]]
 
@@ -425,7 +425,7 @@ bb0(%0 : $Int):
 }
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @partial_apply_complex_generic_function(i64 %0, ptr %T, ptr %T.P2, ptr %T.Y.P2)
 // CHECK:      [[T0:%.*]] = call noalias ptr @swift_allocObject(ptr {{.*}}, i64 48, i64 7)
-// CHECK-NEXT: [[BUFFER:%.*]] = getelementptr inbounds <{ %swift.refcounted, [24 x i8], %TSi }>, ptr [[T0]], i32 0, i32 1
+// CHECK-NEXT: [[BUFFER:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [24 x i8], %TSi }>, ptr [[T0]], i32 0, i32 1
 // CHECK-NEXT: store ptr %T, ptr [[BUFFER]], align 8
 // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds ptr, ptr [[BUFFER]], i32 1
 // CHECK-NEXT: store ptr %T.P2, ptr [[T0]], align 8
@@ -472,7 +472,7 @@ sil public_external @generic_indirect_return : $@convention(thin) <T> (Int) -> @
 // CHECK-LABEL: define{{.*}} @partial_apply_generic_indirect_return
 // CHECK: insertvalue {{.*}}$s23generic_indirect_returnTA
 
-// CHECK-LABEL: define internal swiftcc void @"$s23generic_indirect_returnTA"(ptr noalias nocapture sret({{.*}}) %0, ptr swiftself
+// CHECK-LABEL: define internal swiftcc void @"$s23generic_indirect_returnTA"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr swiftself
 // CHECK:  call swiftcc void @generic_indirect_return({{.*}} %0,
 // CHECK:  ret void
 sil @partial_apply_generic_indirect_return : $@convention(thin) (Int) -> @callee_owned () -> @owned GenericEnum<Int> {
@@ -500,7 +500,7 @@ sil public_external @generic_indirect_return2 : $@convention(thin) <T> (Int) ->
 // CHECK: [[R2:%.*]] = insertvalue { ptr, ptr } [[R1]], ptr [[CTX2]], 1
 // CHECK: ret { ptr, ptr } [[R2]]
 
-// CHECK-LABEL: define internal swiftcc void @"$s24generic_indirect_return2TA"(ptr noalias nocapture sret({{.*}}) %0, ptr swiftself %1)
+// CHECK-LABEL: define internal swiftcc void @"$s24generic_indirect_return2TA"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr swiftself %1)
 // CHECK: call swiftcc void @generic_indirect_return2(ptr noalias sret({{.*}}) %0,
 // CHECK:  ret void
 sil @partial_apply_generic_indirect_return2 : $@convention(thin) (Int) -> @callee_owned () -> @owned GenericEnum2<Int> {
@@ -617,7 +617,7 @@ bb0(%x : $*SwiftClassPair):
 sil public_external @use_closure2 : $@convention(thin) (@noescape @callee_guaranteed (Int) -> Int) -> ()
 
 // CHECK-LABEL: define{{.*}} swiftcc void @partial_apply_stack_callee_guaranteed_indirect_guaranteed_class_pair_param(ptr {{.*}} %0)
-// CHECK:   [[CLOSURE_STACK_ADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr {{.*}}, i32 0, i32 1
+// CHECK:   [[CLOSURE_STACK_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr {{.*}}, i32 0, i32 1
 // CHECK:   store ptr %0, ptr [[CLOSURE_STACK_ADDR]]
 // CHECK:   call swiftcc void @use_closure2(ptr [[FORWARDER:@[^,]*]], ptr {{.*}})
 // CHECK:   ret void
@@ -641,7 +641,7 @@ bb0(%x : $*SwiftClassPair):
 }
 
 // CHECK: define{{.*}} swiftcc void @partial_apply_stack_callee_guaranteed_indirect_in_class_pair_param(ptr {{.*}} %0)
-// CHECK:   [[CLOSURE_STACK_ADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr {{.*}}, i32 0, i32 1
+// CHECK:   [[CLOSURE_STACK_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr {{.*}}, i32 0, i32 1
 // CHECK:   store ptr %0, ptr [[CLOSURE_STACK_ADDR]]
 // CHECK:   call swiftcc void @use_closure2(ptr [[FORWARDER:@[^,]*]], ptr {{.*}})
 // CHECK:   ret void
@@ -675,7 +675,7 @@ sil public_external @closure : $@convention(thin) (@in_guaranteed ResilientInt,
 // CHECK:   [[MD:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 // CHECK:   [[VWT_PTR:%.*]] = getelementptr inbounds ptr, ptr [[MD]], i64 -1
 // CHECK:   [[VWT:%.*]] = load ptr, ptr [[VWT_PTR]]
-// CHECK:   [[FLAGS_PTR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+// CHECK:   [[FLAGS_PTR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
 // CHECK:   [[FLAGS:%.*]] = load i32, ptr [[FLAGS_PTR]]
 // CHECK:   [[FLAGS2:%.*]] = zext i32 [[FLAGS]] to i64
 // CHECK:   [[ALIGNMASK:%.*]] = and i64 [[FLAGS2]], 255
diff --git a/test/IRGen/partial_apply_coro.sil b/test/IRGen/partial_apply_coro.sil
index 807a2d869ad7f..b496967faa999 100644
--- a/test/IRGen/partial_apply_coro.sil
+++ b/test/IRGen/partial_apply_coro.sil
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -enable-library-evolution -emit-module-path=%t/resilient_struct.swiftmodule -module-name=resilient_struct %S/../Inputs/resilient_struct.swift
-// RUN: %target-swift-frontend -Xllvm -sil-disable-pass=OnoneSimplification -I %t -emit-ir %s -o - | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-cpu
+// RUN: %target-swift-frontend -Xllvm -sil-disable-pass=OnoneSimplification -I %t -emit-ir -disable-emit-type-malloc-for-coro-frame %s -o - | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-cpu
 
 // REQUIRES: concurrency
 
@@ -46,10 +46,10 @@ bb2:
 // CHECK-NEXT: entry:
 // CHECK-NEXT:   %[[CTX:.*]] = alloca [[[BUFFER_SIZE]] x i8]
 // CHECK-NEXT:   %[[PA_CTX_BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata
-// CHECK-NEXT:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-NEXT:   %[[PA_ARG:.*]] = getelementptr inbounds %TSf, ptr %[[PA_CTX]], i32 0, i32 0
+// CHECK-NEXT:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-NEXT:   %[[PA_ARG:.*]] = getelementptr inbounds{{.*}} %TSf, ptr %[[PA_CTX]], i32 0, i32 0
 // CHECK-NEXT:   store float %[[ARG]], ptr %[[PA_ARG]]
-// CHECK-NEXT:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
+// CHECK-NEXT:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
 // CHECK-NEXT:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK-NEXT:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, float } @"$s6yield1TA{{.*}}"(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTXPTR]], ptr swiftself %[[PA_CTX_BOX]])
 // CHECK-NEXT:   %[[RESUME:.*]] = extractvalue { ptr, float } %[[YIELD_PAIR]], 0
@@ -71,10 +71,10 @@ bb2:
 // CHECK-NEXT:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK-NEXT:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK-NEXT:   %[[FRAME:.*]] = getelementptr inbounds %"$s6yield1TA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK-NEXT:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-NEXT:   %[[PA_ARG:.*]] = getelementptr inbounds %TSf, ptr %[[PA_CTX]], i32 0, i32 0
+// CHECK-NEXT:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-NEXT:   %[[PA_ARG:.*]] = getelementptr inbounds{{.*}} %TSf, ptr %[[PA_CTX]], i32 0, i32 0
 // CHECK-NEXT:   %[[ARG:.*]] = load float, ptr %[[PA_ARG]]
-// CHECK-NEXT:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK-NEXT:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK-NEXT:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK-NEXT:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, float } @yield1(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], float %[[ARG]])
 // CHECK-NEXT:   %[[RESUME:.*]] = extractvalue { ptr, float } %[[YIELD_PAIR]], 0
@@ -99,7 +99,7 @@ bb2:
 // CHECK-LABEL: unwind:
 // CHECK:        %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s6yield1TA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK-NEXT:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK-NEXT:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK-NEXT:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK-NEXT:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK-NEXT:   call void @free(ptr %[[FRAME]])
 // CHECK-NEXT:   unreachable
@@ -107,7 +107,7 @@ bb2:
 // CHECK-LABEL: resume:
 // CHECK:        %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s6yield1TA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK-NEXT:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK-NEXT:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK-NEXT:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK-NEXT:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK-NEXT:   call void @free(ptr %[[FRAME]])
 // CHECK-NEXT:   ret void
@@ -174,14 +174,14 @@ bb2:
 // CHECK-NEXT: entry:
 // CHECK-NEXT:   %[[CTX:.*]] = alloca [[[BUFFER_SIZE]] x i8]
 // CHECK-NEXT:   %[[PA_CTX_BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata.{{.*}}
-// CHECK-NEXT:   %[[PA_CTX0:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSi, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-NEXT:   %[[PA_ARG0:.*]] = getelementptr inbounds %TSi, ptr %[[PA_CTX0]], i32 0, i32 0
+// CHECK-NEXT:   %[[PA_CTX0:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSi, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-NEXT:   %[[PA_ARG0:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[PA_CTX0]], i32 0, i32 0
 // CHECK-64-NEXT:   store i64 %[[ARG0]], ptr %[[PA_ARG0]], align 8
 // CHECK-32-NEXT:   store i32 %[[ARG0]], ptr %[[PA_ARG0]], align 4
-// CHECK-NEXT:   %[[PA_CTX1:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSi, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
-// CHECK-NEXT:   %[[PA_ARG1:.*]] = getelementptr inbounds %TSf, ptr %[[PA_CTX1]], i32 0, i32 0
+// CHECK-NEXT:   %[[PA_CTX1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSi, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK-NEXT:   %[[PA_ARG1:.*]] = getelementptr inbounds{{.*}} %TSf, ptr %[[PA_CTX1]], i32 0, i32 0
 // CHECK-NEXT:   store float %[[ARG1]], ptr %[[PA_ARG1]]
-// CHECK-NEXT:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
+// CHECK-NEXT:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
 // CHECK-NEXT:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK-NEXT:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, float } @"$s6yield2TA{{.*}}"(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTXPTR]], ptr swiftself %[[PA_CTX_BOX]])
 // CHECK-NEXT:   %[[RESUME:.*]] = extractvalue { ptr, float } %[[YIELD_PAIR]], 0
@@ -202,13 +202,13 @@ bb2:
 // CHECK-NEXT:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK-NEXT:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK-NEXT:   %[[FRAME:.*]] = getelementptr inbounds %"$s6yield2TA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK-NEXT:   %[[BOXPTR0:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSi, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-NEXT:   %[[ARG0PTR:.*]] = getelementptr inbounds %TSi, ptr %[[BOXPTR0]], i32 0, i32 0
+// CHECK-NEXT:   %[[BOXPTR0:.*]] = getelementptr inbounds{{.*}} <{  %swift.refcounted, %TSi, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-NEXT:   %[[ARG0PTR:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[BOXPTR0]], i32 0, i32 0
 // CHECK-NEXT:   %[[ARG0:.*]] = load [[ARGTYPE:i(32|64)]], ptr %[[ARG0PTR]]
-// CHECK-NEXT:   %[[BOXPTR1:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSi, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
-// CHECK-NEXT:   %[[ARG1PTR:.*]] = getelementptr inbounds %TSf, ptr %[[BOXPTR1]], i32 0, i32 0
+// CHECK-NEXT:   %[[BOXPTR1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSi, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK-NEXT:   %[[ARG1PTR:.*]] = getelementptr inbounds{{.*}} %TSf, ptr %[[BOXPTR1]], i32 0, i32 0
 // CHECK-NEXT:   %[[ARG1:.*]] = load float, ptr %[[ARG1PTR]]
-// CHECK-NEXT:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK-NEXT:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK-NEXT:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK-NEXT:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, float } @yield2(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARGTYPE]] %[[ARG0]], float %[[ARG1]])
 // CHECK-NEXT:   %[[RESUME:.*]] = extractvalue { ptr, float } %[[YIELD_PAIR]], 0
@@ -235,7 +235,7 @@ bb2:
 // CHECK-LABEL: unwind:
 // CHECK:        %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s6yield2TA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK-NEXT:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK-NEXT:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK-NEXT:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK-NEXT:   %{{.*}} = call swiftcc [[ARGTYPE]] %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK-NEXT:   call void @free(ptr %[[FRAME]])
 // CHECK-NEXT:   unreachable
@@ -243,7 +243,7 @@ bb2:
 // CHECK-LABEL: resume:
 // CHECK:        %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s6yield2TA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK-NEXT:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK-NEXT:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK-NEXT:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK-NEXT:   %[[RET:.*]] = call swiftcc [[ARGTYPE]] %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK-NEXT:   call void @free(ptr %[[FRAME]])
 // CHECK-NEXT:   ret [[ARGTYPE]] %[[RET]]
@@ -298,7 +298,7 @@ bb2:
 // CHECK-SAMEL (float %[[ARG:.*]])
 // CHECK-NEXT: entry:
 // CHECK:   %[[CTX:.*]] = alloca [[[BUFFER_SIZE]] x i8]
-// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
+// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @"$s9yieldgen1TA{{.*}}"(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTXPTR]], ptr swiftself
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -315,7 +315,7 @@ bb2:
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s9yieldgen1TA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @yieldgen1(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr noalias %[[PA_CTX_BOX2:.*]], ptr @"$sSfN")
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -339,7 +339,7 @@ bb2:
 // CHECK-64: %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s9yieldgen1TA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK-32: %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s9yieldgen1TA.Frame", ptr %[[FRAME]], i32 0, i32 2
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -348,7 +348,7 @@ bb2:
 // CHECK-64:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s9yieldgen1TA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK-32:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s9yieldgen1TA.Frame", ptr %[[FRAME]], i32 0, i32 2
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -424,14 +424,14 @@ bb2:
 // CHECK:   %[[INDIRECT_RET:.*]] = alloca %TSf, align 4
 // CHECK:   %[[CTX:.*]] = alloca [[[BUFFER_SIZE]] x i8]
 // CHECK:   call void @llvm.lifetime.start.p0(i64 4, ptr %[[ARG_COPY]])
-// CHECK:   %[[ARG_COPY_PTR:.*]] = getelementptr inbounds %TSf, ptr %[[ARG_COPY]], i32 0, i32 0
+// CHECK:   %[[ARG_COPY_PTR:.*]] = getelementptr inbounds{{.*}} %TSf, ptr %[[ARG_COPY]], i32 0, i32 0
 // CHECK:   store float %[[ARG]], ptr %[[ARG_COPY_PTR]], align 4
 // CHECK:   %[[PA_CTX_BOX:.*]] = call noalias ptr @swift_allocObject
-// CHECK:   %[[PA_CTX_ARG:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX_ARG:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSf }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK-64:   call void @llvm.memcpy.p0.p0.i64(ptr align 8 %[[PA_CTX_ARG]], ptr align 4 %[[ARG_COPY]], i64 4, i1 false)
 // CHECK-32:   call void @llvm.memcpy.p0.p0.i32(ptr align 4 %[[PA_CTX_ARG]], ptr align 4 %[[ARG_COPY]], i32 4, i1 false)
 // CHECK:   call void @llvm.lifetime.start.p0(i64 4, ptr %[[INDIRECT_RET]])
-// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
+// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @"$s9yieldgen2TA{{.*}}"(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTXPTR]], ptr %[[INDIRECT_RET]], ptr swiftself
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -451,11 +451,11 @@ bb2:
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK-NEXT:   %[[SPILL2:.*]] = getelementptr inbounds %"$s9yieldgen2TA.Frame", ptr %[[SPILL]], i32 0
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s9yieldgen2TA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[ARG:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSf }>, ptr %[[PA_BOX_CTX:.*]], i32 0, i32 1
+// CHECK:   %[[ARG:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSf }>, ptr %[[PA_BOX_CTX:.*]], i32 0, i32 1
 // CHECK:   call void @llvm.lifetime.start.p0(i64 4, ptr %[[SPILL2:.*]])
 // CHECK-64:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %[[SPILL2:.*]], ptr align 8 %[[ARG]], i64 4, i1 false)
 // CHECK-32:   call void @llvm.memcpy.p0.p0.i32(ptr align 4 %[[SPILL2:.*]], ptr align 4 %[[ARG]], i32 4, i1 false)
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @yieldgen2(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr %[[INDIRECT_RET]], ptr noalias %[[SPILL2]], ptr @"$sSfN")
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -479,7 +479,7 @@ bb2:
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s9yieldgen2TA.Frame", ptr %[[FRAME]], i32 0
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0:.*]]
-// CHECK:   %[[CTX:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -488,7 +488,7 @@ bb2:
 // CHECK-64:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s9yieldgen2TA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK-32:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s9yieldgen2TA.Frame", ptr %[[FRAME]], i32 0, i32 2
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -561,7 +561,7 @@ bb2:
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s28partially_applyable_to_classTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @partially_applyable_to_class(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr %[[PA_CTX_BOX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -583,7 +583,7 @@ bb2:
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s28partially_applyable_to_classTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -591,7 +591,7 @@ bb2:
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s28partially_applyable_to_classTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -621,7 +621,7 @@ sil @use_closure_two : $@convention(thin) (@noescape @yield_once @callee_guarant
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s28partially_applyable_to_classTA.{{[0-9]+}}.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @partially_applyable_to_class(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr %[[PA_CTX_BOX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -643,7 +643,7 @@ sil @use_closure_two : $@convention(thin) (@noescape @yield_once @callee_guarant
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s28partially_applyable_to_classTA.{{[0-9]+}}.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -651,7 +651,7 @@ sil @use_closure_two : $@convention(thin) (@noescape @yield_once @callee_guarant
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s28partially_applyable_to_classTA.{{[0-9]+}}.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -703,9 +703,9 @@ bb2:
 // CHECK-SAME: (ptr %[[ARG0:.*]], ptr %[[ARG1:.*]])
 // CHECK: entry:
 // CHECK:   %[[BOX:.*]] = alloca i8, {{(i32|i64)}} [[BUFFER_SIZE]], align 16
-// CHECK:   %[[BOXPTR0:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr, ptr }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[BOXPTR0:.*]] = getelementptr inbounds{{.*}} <{  %swift.refcounted, ptr, ptr }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   store ptr %[[ARG0]], ptr %[[BOXPTR0]]
-// CHECK:   %[[BOXPTR1:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr, ptr }>, ptr %[[BOX]], i32 0, i32 2
+// CHECK:   %[[BOXPTR1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr, ptr }>, ptr %[[BOX]], i32 0, i32 2
 // CHECK:   store ptr %[[ARG1]], ptr %[[BOXPTR1]]
 // CHECK:   call swiftcc void @use_closure_two(ptr @"$s34partially_applyable_to_two_classesTA{{.*}}", ptr %[[BOX]])
 // CHECK:   call void @swift_release(ptr %[[ARG0]])
@@ -719,11 +719,11 @@ bb2:
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s34partially_applyable_to_two_classesTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX0:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX0:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[ARG0:.*]] = load ptr, ptr %[[PA_CTX0]]
-// CHECK:   %[[PA_CTX1:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK:   %[[PA_CTX1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
 // CHECK:   %[[ARG1:.*]] = load ptr, ptr %[[PA_CTX1]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @partially_applyable_to_two_classes(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr %[[ARG0]], ptr %[[ARG1]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -745,7 +745,7 @@ bb2:
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s34partially_applyable_to_two_classesTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   %{{.*}} = call swiftcc ptr %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -753,7 +753,7 @@ bb2:
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s34partially_applyable_to_two_classesTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   %[[RET:.*]] = call swiftcc ptr %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret ptr %[[RET]]
@@ -804,10 +804,10 @@ bb2:
 // CHECK: entry:
 // CHECK:   %[[ARG:.*]] = alloca %TSi
 // CHECK:   call void @llvm.lifetime.start.p0(i64 {{4|8}}, ptr %[[ARG]])
-// CHECK:   %[[ARGPTR:.*]] = getelementptr inbounds %TSi, ptr %[[ARG]], i32 0, i32 0
+// CHECK:   %[[ARGPTR:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[ARG]], i32 0, i32 0
 // CHECK:   store [[ARG_TYPE]] %[[ARG0]], ptr %[[ARGPTR]]
 // CHECK:   %[[BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata.{{.*}}
-// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   store ptr %[[ARG]], ptr %[[BOXPTR]]
 // CHECK:   call void @llvm.lifetime.end.p0(i64 {{4|8}}, ptr %[[ARG]])
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s22generic_captured_paramTA{{.*}}", ptr undef }, ptr %[[BOX]], 1
@@ -821,9 +821,9 @@ bb2:
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s22generic_captured_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[ARG1:.*]] = load ptr, ptr %[[PA_CTX]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @generic_captured_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr %[[ARG1]], ptr @"$sSiN")
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
@@ -845,7 +845,7 @@ bb2:
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s22generic_captured_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -853,7 +853,7 @@ bb2:
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s22generic_captured_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -881,9 +881,9 @@ entry(%i : $*T, %io : $*T):
 // CHECK-SAME: (ptr %[[ARG0:.*]], ptr %[[ARG1:.*]])
 // CHECK: entry:
 // CHECK:   %[[BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata
-// CHECK:   %[[BOXPTR1:.*]] = getelementptr inbounds <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[BOXPTR1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   store ptr %[[ARG1]], ptr %[[BOXPTR1]]
-// CHECK:   %[[BOXPTR2:.*]] = getelementptr inbounds <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr %[[BOX]], i32 0, i32 2
+// CHECK:   %[[BOXPTR2:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr %[[BOX]], i32 0, i32 2
 // CHECK:   store ptr %[[ARG0]], ptr %[[BOXPTR2]],
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s31generic_captured_and_open_paramTA{{.*}}", ptr undef }, ptr %[[BOX]], 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
@@ -895,11 +895,11 @@ entry(%i : $*T, %io : $*T):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s31generic_captured_and_open_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[ARG1:.*]] = load ptr, ptr %[[PA_CTX]]
-// CHECK:   %[[PA_CTX2:.*]] = getelementptr inbounds <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK:   %[[PA_CTX2:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
 // CHECK:   %[[ARG2:.*]] = load ptr, ptr %[[PA_CTX2]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @generic_captured_and_open_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr noalias %[[ARG0]], ptr %[[ARG2]], ptr %[[ARG1]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -921,7 +921,7 @@ entry(%i : $*T, %io : $*T):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s31generic_captured_and_open_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -929,7 +929,7 @@ entry(%i : $*T, %io : $*T):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s31generic_captured_and_open_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -968,7 +968,7 @@ entry(%i : $Int, %c : $SwiftClass):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s31guaranteed_captured_class_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @guaranteed_captured_class_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr %[[PA_CTX_BOX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -990,7 +990,7 @@ entry(%i : $Int, %c : $SwiftClass):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s31guaranteed_captured_class_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -998,7 +998,7 @@ entry(%i : $Int, %c : $SwiftClass):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s31guaranteed_captured_class_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -1012,7 +1012,7 @@ bb0(%x : $SwiftClass):
 }
 
 // CHECK-LABEL: define {{.*}} { ptr, ptr } @indirect_guaranteed_captured_class_param
-// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE]]) %0, [[ARGTYPE:i32|i64]] %1, ptr noalias nocapture dereferenceable([[ARGPTR_SIZE:4|8]]) %2)
+// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE]]) %0, [[ARGTYPE:i32|i64]] %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[ARGPTR_SIZE:4|8]]) %2)
 sil public @indirect_guaranteed_captured_class_param : $@yield_once @convention(thin) (Int, @in_guaranteed SwiftClass) -> (@yields SwiftClass) {
 entry(%i : $Int, %c : $*SwiftClass):
   %0 = builtin "int_trap"() : $Never
@@ -1020,7 +1020,7 @@ entry(%i : $Int, %c : $*SwiftClass):
 }
 
 // CHECK-LABEL: define {{.*}} { ptr, ptr } @partial_apply_indirect_guaranteed_class_param
-// CHECK-SAME: (ptr noalias nocapture dereferenceable([[ARGPTR_SIZE]]) %[[ARGPTR:.*]])
+// CHECK-SAME: (ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[ARGPTR_SIZE]]) %[[ARGPTR:.*]])
 // CHECK: entry:
 // CHECK:   %[[ARG:.*]] = load ptr, ptr %[[ARGPTR]]
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s40indirect_guaranteed_captured_class_paramTA{{.*}}", ptr undef }, ptr %[[ARG]], 1
@@ -1035,9 +1035,9 @@ entry(%i : $Int, %c : $*SwiftClass):
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s40indirect_guaranteed_captured_class_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
 // CHECK:   store ptr %[[PA_CTX_BOX]], ptr %[[SELFPTR]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @indirect_guaranteed_captured_class_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias nocapture dereferenceable([[ARGPTR_SIZE]]) %[[SELFPTR]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @indirect_guaranteed_captured_class_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[ARGPTR_SIZE]]) %[[SELFPTR]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s40indirect_guaranteed_captured_class_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 1
 // CHECK:   store ptr %[[RESUME]], ptr %[[SPILL2]]
@@ -1057,7 +1057,7 @@ entry(%i : $Int, %c : $*SwiftClass):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s40indirect_guaranteed_captured_class_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -1065,7 +1065,7 @@ entry(%i : $Int, %c : $*SwiftClass):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s40indirect_guaranteed_captured_class_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -1079,7 +1079,7 @@ bb0(%x : $*SwiftClass):
 }
 
 // CHECK-LABEL: define {{.*}} { ptr, ptr } @indirect_consumed_captured_class_param
-// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, [[ARGTYPE:(i32|i64)]] %1, ptr noalias nocapture dereferenceable([[ARGPTR_SIZE:(4|8)]]) %2)
+// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, [[ARGTYPE:(i32|i64)]] %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[ARGPTR_SIZE:(4|8)]]) %2)
 sil public @indirect_consumed_captured_class_param : $@yield_once @convention(thin) (Int, @in SwiftClass) -> (@yields SwiftClass) {
 entry(%i : $Int, %c : $*SwiftClass):
   %0 = builtin "int_trap"() : $Never
@@ -1087,7 +1087,7 @@ entry(%i : $Int, %c : $*SwiftClass):
 }
 
 // CHECK-LABEL: define {{.*}} { ptr, ptr } @partial_apply_indirect_consumed_class_param
-// CHECK-SAME: (ptr noalias nocapture dereferenceable([[ARGPTR_SIZE]]) %[[ARGPTR:.*]])
+// CHECK-SAME: (ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[ARGPTR_SIZE]]) %[[ARGPTR:.*]])
 // CHECK: entry:
 // CHECK:   %[[ARG:.*]] = load ptr, ptr %[[ARGPTR]]
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s38indirect_consumed_captured_class_paramTA{{.*}}", ptr undef }, ptr %[[ARG]], 1
@@ -1103,9 +1103,9 @@ entry(%i : $Int, %c : $*SwiftClass):
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s38indirect_consumed_captured_class_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
 // CHECK:   %{{.*}} = call ptr @swift_retain(ptr returned %[[PA_CTX_BOX]])
 // CHECK:   store ptr %[[PA_CTX_BOX]], ptr %[[SELFPTR]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @indirect_consumed_captured_class_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias nocapture dereferenceable([[ARGPTR_SIZE]]) %[[SELFPTR]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @indirect_consumed_captured_class_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[ARGPTR_SIZE]]) %[[SELFPTR]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s38indirect_consumed_captured_class_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 1
 // CHECK:   store ptr %[[RESUME]], ptr %[[SPILL2]]
@@ -1125,7 +1125,7 @@ entry(%i : $Int, %c : $*SwiftClass):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s38indirect_consumed_captured_class_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -1133,7 +1133,7 @@ entry(%i : $Int, %c : $*SwiftClass):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s38indirect_consumed_captured_class_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -1166,10 +1166,10 @@ entry(%i : $Int, %c : $SwiftClassPair):
 // CHECK-SAME: (ptr %[[ARG0:.*]], ptr %[[ARG1:.*]])
 // CHECK: entry:
 // CHECK:   %[[BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata.{{.*}}
-// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[BOX]], i32 0, i32 1
-// CHECK:   %[[ARG0PTR:.*]] = getelementptr inbounds %T18partial_apply_coro14SwiftClassPairV, ptr %[[BOXPTR]], i32 0, i32 0
+// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[ARG0PTR:.*]] = getelementptr inbounds{{.*}} %T18partial_apply_coro14SwiftClassPairV, ptr %[[BOXPTR]], i32 0, i32 0
 // CHECK:   store ptr %[[ARG0]], ptr %[[ARG0PTR]]
-// CHECK:   %[[ARG1PTR:.*]] = getelementptr inbounds %T18partial_apply_coro14SwiftClassPairV, ptr %[[BOXPTR]], i32 0, i32 1
+// CHECK:   %[[ARG1PTR:.*]] = getelementptr inbounds{{.*}} %T18partial_apply_coro14SwiftClassPairV, ptr %[[BOXPTR]], i32 0, i32 1
 // CHECK:   store ptr %[[ARG1]], ptr %[[ARG1PTR]]
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s36guaranteed_captured_class_pair_paramTA{{.*}}", ptr undef }, ptr %[[BOX]], 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
@@ -1181,12 +1181,12 @@ entry(%i : $Int, %c : $SwiftClassPair):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s36guaranteed_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK:   %[[PA_CTX_ARG1:.*]] = getelementptr inbounds %T18partial_apply_coro14SwiftClassPairV, ptr %[[PA_CTX]], i32 0, i32 0
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX_ARG1:.*]] = getelementptr inbounds{{.*}} %T18partial_apply_coro14SwiftClassPairV, ptr %[[PA_CTX]], i32 0, i32 0
 // CHECK:   %[[ARG1:.*]] = load ptr, ptr %[[PA_CTX_ARG1]]
-// CHECK:   %[[PA_CTX_ARG2:.*]] = getelementptr inbounds %T18partial_apply_coro14SwiftClassPairV, ptr %[[PA_CTX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX_ARG2:.*]] = getelementptr inbounds{{.*}} %T18partial_apply_coro14SwiftClassPairV, ptr %[[PA_CTX]], i32 0, i32 1
 // CHECK:   %[[ARG2:.*]] = load ptr, ptr %[[PA_CTX_ARG2]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @guaranteed_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr %[[ARG1]], ptr %[[ARG2]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
@@ -1208,7 +1208,7 @@ entry(%i : $Int, %c : $SwiftClassPair):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s36guaranteed_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -1216,7 +1216,7 @@ entry(%i : $Int, %c : $SwiftClassPair):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s36guaranteed_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -1231,7 +1231,7 @@ bb0(%x : $SwiftClassPair):
 
 // CHECK-64-LABEL: define {{.*}} { ptr, i64 } @indirect_guaranteed_captured_class_pair_param
 // CHECK-32-LABEL: define {{.*}} { ptr, i32 } @indirect_guaranteed_captured_class_pair_param
-// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, [[ARG_TYPE:(i32|i64)]] %1, ptr noalias nocapture dereferenceable([[PAIR_SIZE:(8|16)]]) %2)
+// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, [[ARG_TYPE:(i32|i64)]] %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE:(8|16)]]) %2)
 sil public @indirect_guaranteed_captured_class_pair_param : $@yield_once @convention(thin) (Int, @in_guaranteed SwiftClassPair) -> (@yields Int) {
 entry(%i : $Int, %c : $*SwiftClassPair):
   %0 = builtin "int_trap"() : $Never
@@ -1239,10 +1239,10 @@ entry(%i : $Int, %c : $*SwiftClassPair):
 }
 
 // CHECK-LABEL: define {{.*}} { ptr, ptr } @partial_apply_indirect_guaranteed_class_pair_param
-// CHECK-SAME: (ptr noalias nocapture dereferenceable([[PAIR_SIZE]]) %[[ARG:.*]])
+// CHECK-SAME: (ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE]]) %[[ARG:.*]])
 // CHECK: entry:
 // CHECK:   %[[BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata.{{.*}}
-// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   call void @llvm.memcpy.p0.p0.[[ARG_TYPE]](ptr align {{4|8}} %[[BOXPTR]], ptr align {{4|8}} %[[ARG]], [[ARG_TYPE]] [[PAIR_SIZE]], i1 false)
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s45indirect_guaranteed_captured_class_pair_paramTA{{.*}}", ptr undef }, ptr %[[BOX]], 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
@@ -1255,10 +1255,10 @@ entry(%i : $Int, %c : $*SwiftClassPair):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[SPILL1:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[SPILL1]], i32 0, i32 0
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[SPILL1]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_guaranteed_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %1, ptr noalias nocapture dereferenceable([[PAIR_SIZE]]) %[[PA_CTX]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_guaranteed_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE]]) %[[PA_CTX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 1
 // CHECK:   store ptr %[[RESUME]], ptr %[[SPILL2]]
@@ -1278,7 +1278,7 @@ entry(%i : $Int, %c : $*SwiftClassPair):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -1286,7 +1286,7 @@ entry(%i : $Int, %c : $*SwiftClassPair):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -1301,7 +1301,7 @@ bb0(%x : $*SwiftClassPair):
 
 // CHECK-32-LABEL: define {{.*}} { ptr, i32 } @indirect_consumed_captured_class_pair_param
 // CHECK-64-LABEL: define {{.*}} { ptr, i64 } @indirect_consumed_captured_class_pair_param
-// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE]]) %0, [[ARG_TYPE]] %1, ptr noalias nocapture dereferenceable([[PAIR_SIZE]]) %2)
+// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE]]) %0, [[ARG_TYPE]] %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE]]) %2)
 sil public @indirect_consumed_captured_class_pair_param : $@yield_once @convention(thin) (Int, @in SwiftClassPair) -> (@yields Int) {
 entry(%i : $Int, %c : $*SwiftClassPair):
   %0 = builtin "int_trap"() : $Never
@@ -1309,10 +1309,10 @@ entry(%i : $Int, %c : $*SwiftClassPair):
 }
 
 // CHECK-LABEL: define {{.*}} { ptr, ptr } @partial_apply_indirect_consumed_class_pair_param
-// CHECK-SAME: (ptr noalias nocapture dereferenceable([[PAIR_SIZE]]) %[[ARG:.*]])
+// CHECK-SAME: (ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE]]) %[[ARG:.*]])
 // CHECK: entry:
 // CHECK:   %[[BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata.{{.*}}
-// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   call void @llvm.memcpy.p0.p0.[[ARG_TYPE]](ptr align {{4|8}} %[[BOXPTR]], ptr align {{4|8}} %[[ARG]], [[ARG_TYPE]] [[PAIR_SIZE]], i1 false)
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s43indirect_consumed_captured_class_pair_paramTA{{.*}}", ptr undef }, ptr %[[BOX]], 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
@@ -1326,12 +1326,12 @@ entry(%i : $Int, %c : $*SwiftClassPair):
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[SPILL1:.*]] = getelementptr inbounds %"$s43indirect_consumed_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 1
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s43indirect_consumed_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[PAIR_SIZE]], ptr %[[SPILL1]])
 // CHECK:   %{{.*}} = call ptr @"$s18partial_apply_coro14SwiftClassPairVWOc"(ptr %[[PA_CTX]], ptr %[[SPILL1]])
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_consumed_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %1, ptr noalias nocapture dereferenceable([[PAIR_SIZE]]) %[[SPILL1]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_consumed_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE]]) %[[SPILL1]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s43indirect_consumed_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 2
 // CHECK:   store ptr %[[RESUME]], ptr %[[SPILL2]]
@@ -1351,7 +1351,7 @@ entry(%i : $Int, %c : $*SwiftClassPair):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s43indirect_consumed_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 2
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -1359,7 +1359,7 @@ entry(%i : $Int, %c : $*SwiftClassPair):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s43indirect_consumed_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 2
 // CHECK:   %[[RESUME:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -1388,24 +1388,24 @@ entry(%c : $SwiftClass, %a : $*A, %i : $Int):
 // CHECK-arm64e: %[[VWTABLEADDR:.*]] = ptrtoint ptr %[[VWTABLE]] to i64
 // CHECK-arm64e: %[[VWTABLEAUTH:.*]] = call i64 @llvm.ptrauth.auth(i64 %[[VWTABLEADDR]], i32 2
 // CHECK-arm64e: %[[VWTABLE:.*]] = inttoptr i64 %[[VWTABLEAUTH]] to ptr
-// CHECK:   %[[WITNESS:.*]] = getelementptr inbounds %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 10
+// CHECK:   %[[WITNESS:.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 10
 // CHECK:   %[[FLAGS:.*]] = load i32, ptr %[[WITNESS]]
 // do not check computation of align; may be target dependent
-// CHECK:   %[[WITNESS_SIZE:.*]] = getelementptr inbounds %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 8
+// CHECK:   %[[WITNESS_SIZE:.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 8
 // do not check computation of size; may be target dependent
 // CHECK:   %[[BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata{{.*}}
-// CHECK-32:   %[[BOXPTR0:.*]] = getelementptr inbounds <{ %swift.refcounted, [4 x i8], ptr }>, ptr %[[BOX]], i32 0, i32 1
-// CHECK-64:   %[[BOXPTR0:.*]] = getelementptr inbounds <{ %swift.refcounted, [8 x i8], ptr }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK-32:   %[[BOXPTR0:.*]] = getelementptr inbounds{{.*}} <{  %swift.refcounted, [4 x i8], ptr }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK-64:   %[[BOXPTR0:.*]] = getelementptr inbounds{{.*}} <{  %swift.refcounted, [8 x i8], ptr }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   store ptr %[[TY]], ptr %[[BOXPTR0]]
-// CHECK-32:   %[[BOXPTR1:.*]] = getelementptr inbounds <{ %swift.refcounted, [4 x i8], ptr }>, ptr %[[BOX]], i32 0, i32 2
-// CHECK-64:   %[[BOXPTR1:.*]] = getelementptr inbounds <{ %swift.refcounted, [8 x i8], ptr }>, ptr %[[BOX]], i32 0, i32 2
+// CHECK-32:   %[[BOXPTR1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [4 x i8], ptr }>, ptr %[[BOX]], i32 0, i32 2
+// CHECK-64:   %[[BOXPTR1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [8 x i8], ptr }>, ptr %[[BOX]], i32 0, i32 2
 // CHECK:   store ptr %[[CTX]], ptr %[[BOXPTR1]]
 // CHECK:   %[[BOXPTR2:.*]] = getelementptr inbounds i8, ptr %[[BOX]]
 // CHECK:   %[[INITPTR:.*]] = getelementptr inbounds ptr, ptr %[[VWTABLE]], i32 4
 // CHECK:   %[[INIT:.*]] = load ptr, ptr %[[INITPTR]]
 // CHECK:   %{{.*}} = call ptr %[[INIT]](ptr noalias %[[BOXPTR2]], ptr noalias %[[ARG0]], ptr %[[TY]])
 // CHECK:   %[[BOXPTR3:.*]] = getelementptr inbounds i8, ptr %[[BOX]], {{i32|i64}} %{{.*}}
-// CHECK:   %[[BOXPTR3VAL:.*]] = getelementptr inbounds %TSi, ptr %[[BOXPTR3]], i32 0, i32 0
+// CHECK:   %[[BOXPTR3VAL:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[BOXPTR3]], i32 0, i32 0
 // CHECK:   store [[ARG_TYPE]] %[[ARG1]], ptr %[[BOXPTR3VAL]]
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s35captured_fixed_and_dependent_paramsTA{{.*}}", ptr undef }, ptr %[[BOX]], 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
@@ -1417,8 +1417,8 @@ entry(%c : $SwiftClass, %a : $*A, %i : $Int):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s35captured_fixed_and_dependent_paramsTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [4 x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [8 x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [4 x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [8 x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[TY:.*]] = load ptr, ptr %[[PA_CTX]]
 // CHECK:   store ptr %[[TY]], ptr %[[TY]]
 // CHECK:   %[[TYMD:.*]] = getelementptr inbounds ptr, ptr %[[TY]], {{i32|i64}} -1
@@ -1426,19 +1426,19 @@ entry(%c : $SwiftClass, %a : $*A, %i : $Int):
 // CHECK-arm64e: %[[VWTABLEADDR:.*]] = ptrtoint ptr %[[VWTABLE]] to i64
 // CHECK-arm64e: %[[VWTABLEAUTH:.*]] = call i64 @llvm.ptrauth.auth(i64 %[[VWTABLEADDR]], i32 2
 // CHECK-arm64e: %[[VWTABLE:.*]] = inttoptr i64 %[[VWTABLEAUTH]] to ptr
-// CHECK:   %[[WITNESS:.*]] = getelementptr inbounds %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 10
+// CHECK:   %[[WITNESS:.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 10
 // CHECK:   %[[FLAGS:.*]] = load i32, ptr %[[WITNESS]]
 // do not check computation of align; may be target dependent
-// CHECK:   %[[WITNESS_SIZE:.*]] = getelementptr inbounds %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 8
+// CHECK:   %[[WITNESS_SIZE:.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 8
 // do not check computation of size; may be target dependent
-// CHECK-32:   %[[PA_CTX2:.*]] = getelementptr inbounds <{ %swift.refcounted, [4 x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
-// CHECK-64:   %[[PA_CTX2:.*]] = getelementptr inbounds <{ %swift.refcounted, [8 x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK-32:   %[[PA_CTX2:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [4 x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK-64:   %[[PA_CTX2:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [8 x i8], ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
 // CHECK:   %[[ARG0:.*]] = load ptr, ptr %[[PA_CTX2]]
 // CHECK:   %[[ARG1:.*]] = getelementptr inbounds i8, ptr %[[PA_CTX_BOX]], {{i32|i64}} %{{.*}}
 // CHECK:   %[[ARG2PTR0:.*]] = getelementptr inbounds i8, ptr %[[PA_CTX_BOX]], {{i32|i64}} %{{.*}}
-// CHECK:   %[[ARG2PTR1:.*]] = getelementptr inbounds %TSi, ptr %[[ARG2PTR0]], i32 0, i32 0
+// CHECK:   %[[ARG2PTR1:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[ARG2PTR0]], i32 0, i32 0
 // CHECK:   %[[ARG2:.*]] = load [[ARG_TYPE]], ptr %[[ARG2PTR1]]
-// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK:   %[[RESUME:.*]] = call swiftcc ptr @captured_fixed_and_dependent_params(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTXPTR]], ptr %[[ARG0]], ptr noalias %[[ARG1]], [[ARG_TYPE]] %[[ARG2]], ptr %T)
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s35captured_fixed_and_dependent_paramsTA.Frame", ptr %[[SPILL]], i32 0, i32 1
@@ -1456,7 +1456,7 @@ entry(%c : $SwiftClass, %a : $*A, %i : $Int):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s35captured_fixed_and_dependent_paramsTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -1464,7 +1464,7 @@ entry(%c : $SwiftClass, %a : $*A, %i : $Int):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s35captured_fixed_and_dependent_paramsTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -1485,14 +1485,14 @@ bb0(%a : $SwiftClass, %b : $*T, %c : $Int):
 // CHECK-arm64e: %[[VWTABLEADDR:.*]] = ptrtoint ptr %[[ARGTY_VW]] to i64
 // CHECK-arm64e: %[[VWTABLEAUTH:.*]] = call i64 @llvm.ptrauth.auth(i64 %[[VWTABLEADDR]], i32 2
 // CHECK-arm64e: %[[ARGTY_VW:.*]] = inttoptr i64 %[[VWTABLEAUTH]] to ptr
-// CHECK:   %[[ARGTY_FLAGS_PTR:.*]] = getelementptr inbounds %swift.vwtable, ptr %[[ARGTY_VW]], i32 0, i32 10
+// CHECK:   %[[ARGTY_FLAGS_PTR:.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr %[[ARGTY_VW]], i32 0, i32 10
 // CHECK:   %[[ARGTY_FLAGS:.*]] = load i32, ptr %[[ARGTY_FLAGS_PTR]]
 // do not check computation of align; may be target dependent
-// CHECK:   %[[ARGTY_SIZE_PTR:.*]] = getelementptr inbounds %swift.vwtable, ptr %[[ARGTY_VW]], i32 0, i32 8
+// CHECK:   %[[ARGTY_SIZE_PTR:.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr %[[ARGTY_VW]], i32 0, i32 8
 // do not check computation of size; may be target dependent
 // CHECK:   %[[PA_BOX_ALLOC:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @{{.*}}
-// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [4 x i8] }>, ptr %[[PA_BOX_ALLOC]], i32 0, i32 1
-// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [8 x i8] }>, ptr %[[PA_BOX_ALLOC]], i32 0, i32 1
+// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [4 x i8] }>, ptr %[[PA_BOX_ALLOC]], i32 0, i32 1
+// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [8 x i8] }>, ptr %[[PA_BOX_ALLOC]], i32 0, i32 1
 // CHECK:   store ptr %[[ARGTY]], ptr %[[PA_CTX]]
 // CHECK:   %[[PA_CTX_ARG:.*]] = getelementptr inbounds i8, ptr %[[PA_BOX_ALLOC]],
 // CHECK:   %[[INIT_PTR:.*]] = getelementptr inbounds ptr, ptr %[[ARGTY_VW]], i32 4
@@ -1507,18 +1507,18 @@ bb0(%a : $SwiftClass, %b : $*T, %c : $Int):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s28captured_dependent_out_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [4 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [8 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [4 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [8 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[TY:.*]] = load ptr, ptr %[[PA_CTX]]
 // CHECK:   %[[TYMD:.*]] = getelementptr inbounds ptr, ptr %[[TY]], {{i32|i64}} -1
 // CHECK:   %[[VWTABLE:.*]] = load ptr, ptr %[[TYMD]]
 // CHECK-arm64e: %[[VWTABLEADDR:.*]] = ptrtoint ptr %[[VWTABLE]] to i64
 // CHECK-arm64e: %[[VWTABLEAUTH:.*]] = call i64 @llvm.ptrauth.auth(i64 %[[VWTABLEADDR]], i32 2
 // CHECK-arm64e: %[[VWTABLE:.*]] = inttoptr i64 %[[VWTABLEAUTH]] to ptr
-// CHECK:   %[[WITNESS:.*]] = getelementptr inbounds %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 10
+// CHECK:   %[[WITNESS:.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 10
 // CHECK:   %[[FLAGS:.*]] = load i32, ptr %[[WITNESS]]
 // do not check computation of align; may be target dependent
-// CHECK:   %[[WITNESS_SIZE:.*]] = getelementptr inbounds %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 8
+// CHECK:   %[[WITNESS_SIZE:.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr %[[VWTABLE]], i32 0, i32 8
 // do not check computation of size; may be target dependent
 // CHECK:   %[[PA_CTX2:.*]] = getelementptr inbounds i8, ptr %[[PA_CTX_BOX]]
 // CHECK:   %[[ARG_COPY:.*]] = call ptr @malloc
@@ -1526,7 +1526,7 @@ bb0(%a : $SwiftClass, %b : $*T, %c : $Int):
 // CHECK:   %[[INIT_PTR:.*]] = getelementptr inbounds ptr, ptr %[[VWTABLE]], i32 2
 // CHECK:   %[[INIT:.*]] = load ptr, ptr %[[INIT_PTR]]
 // CHECK:   call ptr %[[INIT]](ptr noalias %[[ARG_COPY]], ptr noalias %[[PA_CTX2]], ptr %[[TY]])
-// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @captured_dependent_out_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTXPTR]], ptr %[[INDIRECT_RET]], ptr noalias %[[ARG_COPY]], ptr %[[TY]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -1555,15 +1555,15 @@ bb0(%x : $*T):
 // CHECK-SAME: (i32 %[[ARG1:.*]], ptr %[[ARG_FUNC:.*]], ptr %[[ARG_FUNC_SELF:.*]], ptr %[[TY:.*]])
 // CHECK: entry:
 // CHECK:   %[[PA_CTX_BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata
-// CHECK-32:   %[[PA_ARG1:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-64:   %[[PA_ARG1:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK:   %[[PA_ARG1_INT:.*]] = getelementptr inbounds %Ts5Int32V, ptr %[[PA_ARG1]], i32 0, i32 0
+// CHECK-32:   %[[PA_ARG1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-64:   %[[PA_ARG1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_ARG1_INT:.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr %[[PA_ARG1]], i32 0, i32 0
 // CHECK:   store i32 %[[ARG1]], ptr %[[PA_ARG1_INT]]
-// CHECK-32:   %[[PA_ARG_FUNC_SELF:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
-// CHECK-64:   %[[PA_ARG_FUNC_SELF:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 3
+// CHECK-32:   %[[PA_ARG_FUNC_SELF:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK-64:   %[[PA_ARG_FUNC_SELF:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 3
 // CHECK:   store ptr %[[ARG_FUNC_SELF]], ptr %[[PA_ARG_FUNC_SELF]]
-// CHECK-32:   %[[PA_ARG_FUNC:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 3
-// CHECK-64:   %[[PA_ARG_FUNC:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 4
+// CHECK-32:   %[[PA_ARG_FUNC:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 3
+// CHECK-64:   %[[PA_ARG_FUNC:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 4
 // CHECK-arm64e: %[[ARG_FUNC_ADDR:.*]] = ptrtoint ptr %[[ARG_FUNC]] to i64
 // CHECK-arm64e: %[[ARG_FUNC_AUTH:.*]] = call i64 @llvm.ptrauth.resign(i64 %[[ARG_FUNC_ADDR]]
 // CHECK-arm64e: %[[ARG_FUNC:.*]] = inttoptr i64 %[[ARG_FUNC_AUTH]] to ptr
@@ -1578,17 +1578,17 @@ bb0(%x : $*T):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$sTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK-32:   %[[PA_ARG1:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-64:   %[[PA_ARG1:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK:   %[[PA_ARG1_INT:.*]] = getelementptr inbounds %Ts5Int32V, ptr %[[PA_ARG1]], i32 0, i32 0
+// CHECK-32:   %[[PA_ARG1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-64:   %[[PA_ARG1:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_ARG1_INT:.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr %[[PA_ARG1]], i32 0, i32 0
 // CHECK:   %[[ARG1:.*]] = load i32, ptr %[[PA_ARG1_INT]]
-// CHECK-32:   %[[PA_ARG_FUNC_SELF:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
-// CHECK-64:   %[[PA_ARG_FUNC_SELF:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 3
+// CHECK-32:   %[[PA_ARG_FUNC_SELF:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK-64:   %[[PA_ARG_FUNC_SELF:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 3
 // CHECK:   %[[ARG_FUNC_SELF:.*]] = load ptr, ptr %[[PA_ARG_FUNC_SELF]]
-// CHECK-32:   %[[PA_ARG_FUNC:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V,  ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 3
-// CHECK-64:   %[[PA_ARG_FUNC:.*]] = getelementptr inbounds <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 4
+// CHECK-32:   %[[PA_ARG_FUNC:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V,  ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 3
+// CHECK-64:   %[[PA_ARG_FUNC:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %Ts5Int32V, [4 x i8], ptr, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 4
 // CHECK:   %[[ARG_FUNC:.*]] = load ptr, ptr %[[PA_ARG_FUNC]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } %[[ARG_FUNC]](ptr noalias {{.*}} %[[FRAMEPTR]], ptr %[[INDIRECT_RET]], i32 %[[ARG1]], ptr swiftself %[[ARG_FUNC_SELF]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -1671,14 +1671,14 @@ bb2:
 // CHECK: entry:
 // CHECK:   %[[CTX0:.*]] = alloca [[[BUFFER_SIZE]] x i8]
 // CHECK:   %[[CTX1:.*]] = alloca [[[BUFFER_SIZE]] x i8]
-// CHECK:   %[[CTX0PTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX0]], i32 0, i32 0
+// CHECK:   %[[CTX0PTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX0]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTX0PTR]])
 // CHECK:   %[[MDRESP:.*]] = call swiftcc %swift.metadata_response @"$s18partial_apply_coro3SubCMa"
 // CHECK:   %[[MD:.*]] = extractvalue %swift.metadata_response %[[MDRESP]], 0
 // CHECK:   %[[RESUME0:.*]] = call swiftcc ptr @receive_closure(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0PTR]], ptr @"$s26parametric_casting_closureTA.{{[0-9]+}}{{.*}}", ptr %[[ARG0]], ptr %[[MD]])
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0PTR]], i1 false)
 // CHECK:   call void @llvm.lifetime.end.p0(i64 [[BUFFER_SIZE]], ptr %[[CTX0PTR]])
-// CHECK:   %[[CTX1PTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX1]], i32 0, i32 0
+// CHECK:   %[[CTX1PTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX1]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTX1PTR]])
 // CHECK:   %[[RESUME1:.*]] = call swiftcc ptr @receive_closure2(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1PTR]], ptr @"$s26parametric_casting_closureTA{{.*}}", ptr null, ptr %[[MD]])
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1PTR]], i1 false)
@@ -1694,7 +1694,7 @@ bb2:
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s26parametric_casting_closureTA.Frame", ptr %[[SPILL]], i32 0, i32 0
 // CHECK:   %[[MDRESP:.*]] = call swiftcc %swift.metadata_response @"$s18partial_apply_coro3SubCMa"
 // CHECK:   %[[MD:.*]] = extractvalue %swift.metadata_response %[[MDRESP]], 0
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @parametric_casting_closure(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr %1, ptr %[[MD]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -1716,7 +1716,7 @@ bb2:
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s26parametric_casting_closureTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   %{{.*}} = call swiftcc ptr %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -1724,7 +1724,7 @@ bb2:
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s26parametric_casting_closureTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   %[[RET:.*]] = call swiftcc ptr %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret ptr %[[RET]]
@@ -1738,7 +1738,7 @@ bb2:
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s26parametric_casting_closureTA.{{[0-9]+}}.Frame", ptr %[[SPILL]], i32 0, i32 0
 // CHECK:   %[[MDRESP:.*]] = call swiftcc %swift.metadata_response @"$s18partial_apply_coro3SubCMa"
 // CHECK:   %[[MD:.*]] = extractvalue %swift.metadata_response %[[MDRESP]], 0
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @parametric_casting_closure(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr %[[PA_CTX_BOX]], ptr %[[MD]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -1760,7 +1760,7 @@ bb2:
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s26parametric_casting_closureTA.{{[0-9]+}}.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]],
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   %{{.*}} = call swiftcc ptr %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -1768,7 +1768,7 @@ bb2:
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s26parametric_casting_closureTA.{{[0-9]+}}.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   %[[RET:.*]] = call swiftcc ptr %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret ptr %[[RET]]
@@ -1803,18 +1803,18 @@ protocol P2 { associatedtype Y : P1 }
 // CHECK: entry:
 // CHECK:   %[[CTX:.*]] = alloca [[[BUFFER_SIZE]] x i8]
 // CHECK:   %[[PA_CTX_BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, {{.*}}
-// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [12 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [24 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [12 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [24 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   store ptr %[[TY1]], ptr %[[PA_CTX]]
 // CHECK:   %[[PA_CTX1:.*]] = getelementptr inbounds ptr, ptr %[[PA_CTX]], i32 1
 // CHECK:   store ptr %[[TY2]], ptr %[[PA_CTX1]]
 // CHECK:   %[[PA_CTX2:.*]] = getelementptr inbounds ptr, ptr %[[PA_CTX]], i32 2
 // CHECK:   store ptr %[[TY3]], ptr %[[PA_CTX2]]
-// CHECK-32:   %[[PA_ARG:.*]] = getelementptr inbounds <{ %swift.refcounted, [12 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
-// CHECK-64:   %[[PA_ARG:.*]] = getelementptr inbounds <{ %swift.refcounted, [24 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
-// CHECK:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds %TSi, ptr %[[PA_ARG]], i32 0, i32 0
+// CHECK-32:   %[[PA_ARG:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [12 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK-64:   %[[PA_ARG:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [24 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[PA_ARG]], i32 0, i32 0
 // CHECK:   store [[ARG_TYPE]] %[[ARG]], ptr %[[PA_ARG_PTR]]
-// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
+// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @"$s24complex_generic_functionTA{{.*}}"(ptr noalias {{.*}} %[[CTXPTR]], ptr swiftself %[[PA_CTX_BOX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -1830,19 +1830,19 @@ protocol P2 { associatedtype Y : P1 }
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s24complex_generic_functionTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [12 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [24 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [12 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [24 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[TY1:.*]] = load ptr, ptr %[[PA_CTX]]
 // CHECK:   %[[TY2_PTR:.*]] = getelementptr inbounds ptr, ptr %[[PA_CTX]], i32 1
 // CHECK:   %[[TY2:.*]] = load ptr, ptr %[[TY2_PTR]]
 // CHECK:   %[[TY3_PTR:.*]] = getelementptr inbounds ptr, ptr %[[PA_CTX]], i32 2
 // CHECK:   %[[TY3:.*]] = load ptr, ptr %[[TY3_PTR]]
-// CHECK-32:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds <{ %swift.refcounted, [12 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
-// CHECK-64:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds <{ %swift.refcounted, [24 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
-// CHECK:   %[[PA_ARG:.*]] = getelementptr inbounds %TSi, ptr %[[PA_ARG_PTR]], i32 0, i32 0
+// CHECK-32:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [12 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK-64:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [24 x i8], %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 2
+// CHECK:   %[[PA_ARG:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[PA_ARG_PTR]], i32 0, i32 0
 // CHECK:   %[[ARG:.*]] = load [[ARG_TYPE]], ptr %[[PA_ARG]]
 // CHECK:   call void @swift_release(ptr %[[PA_CTX_BOX]])
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @complex_generic_function(ptr noalias {{.*}} %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG]], ptr %[[TY1]], ptr %[[TY2]], ptr %[[TY3]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -1871,12 +1871,12 @@ bb0(%0 : $Int):
 // CHECK: entry:
 // CHECK:   %[[CTX:.*]] = alloca [[[BUFFER_SIZE]] x i8]
 // CHECK:   %[[PA_CTX_BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, {{.*}})
-// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [4 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [8 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [4 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [8 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[MD_RES:.*]] = call swiftcc %swift.metadata_response @"$s18partial_apply_coro18ComplexBoundedTypeVMa"({{i32|i64}} 0, ptr %[[TY1]], ptr %[[TY2]])
 // CHECK:   %[[MD:.*]] = extractvalue %swift.metadata_response %[[MD_RES]], 0
 // CHECK:   store ptr %[[MD]], ptr %[[PA_CTX]]
-// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
+// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @"$s16generic_functionTA{{.*}}"(ptr noalias {{.*}} %[[CTXPTR]], ptr swiftself %[[PA_CTX_BOX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -1892,11 +1892,11 @@ bb0(%0 : $Int):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s16generic_functionTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [4 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, [8 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-32:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [4 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK-64:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [8 x i8] }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[MD:.*]] = load ptr, ptr %[[PA_CTX]]
 // CHECK:   call void @swift_release(ptr %[[PA_CTX_BOX]])
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @generic_function(ptr noalias {{.*}} %[[FRAMEPTR]], ptr %[[MD]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -1936,8 +1936,8 @@ entry(%i : $Int):
 // CHECK-SAME: ([[ARG_TYPE:(i32|i64)]] %[[ARG:.*]])
 // CHECK: entry:
 // CHECK:   %[[PA_CTX_BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, {{.*}})
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds %TSi, ptr %[[PA_CTX]], i32 0, i32 0
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[PA_CTX]], i32 0, i32 0
 // CHECK:   store [[ARG_TYPE]] %[[ARG]], ptr %[[PA_ARG_PTR]]
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s23generic_indirect_returnTA{{.*}}", ptr undef }, ptr %[[PA_CTX_BOX]], 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
@@ -1965,8 +1965,8 @@ entry(%i : $Int):
 // CHECK-SAME: ([[ARG_TYPE:(i32|i64)]] %[[ARG:.*]])
 // CHECK: entry:
 // CHECK:   %[[PA_CTX_BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, {{.*}})
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds %TSi, ptr %[[PA_CTX]], i32 0, i32 0
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_ARG_PTR:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[PA_CTX]], i32 0, i32 0
 // CHECK:   store [[ARG_TYPE]] %[[ARG]], ptr %[[PA_ARG_PTR]]
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s24generic_indirect_return2TA{{.*}}", ptr undef }, ptr %[[PA_CTX_BOX]], 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
@@ -2002,7 +2002,7 @@ entry(%t : $@thin SwiftStruct.Type, %c : $SwiftClass):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s3funTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr } @fun(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr %[[PA_CTX_BOX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, ptr } %[[YIELD_PAIR]], 0
@@ -2024,7 +2024,7 @@ entry(%t : $@thin SwiftStruct.Type, %c : $SwiftClass):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s3funTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -2032,7 +2032,7 @@ entry(%t : $@thin SwiftStruct.Type, %c : $SwiftClass):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s3funTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -2059,7 +2059,7 @@ class  A3 {}
 sil_vtable A3 {}
 
 // CHECK-LABEL: define {{.*}} { ptr, ptr, ptr } @amethod
-// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, ptr noalias nocapture swiftself dereferenceable([[SELF_SIZE:(4|8)]]) %1, ptr noalias nocapture swifterror dereferenceable([[ERROR_SIZE:(4|8)]]) %2)
+// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable([[SELF_SIZE:(4|8)]]) %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable([[ERROR_SIZE:(4|8)]]) %2)
 sil @amethod : $@yield_once @convention(method) (@in_guaranteed A2<A3>) -> (@yields A1, @error Error) {
 entry(%a : $*A2<A3>):
   %0 = builtin "int_trap"() : $Never
@@ -2067,23 +2067,23 @@ entry(%a : $*A2<A3>):
 }
 
 // CHECK-LABEL: define {{.*}} { ptr, ptr } @repo
-// CHECK-SAME: (ptr noalias nocapture dereferenceable([[SELF_SIZE]]) %[[ARG:.*]])
+// CHECK-SAME: (ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[SELF_SIZE]]) %[[ARG:.*]])
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s7amethodTA{{.*}}", ptr undef }, ptr %{{.*}}, 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
 // CHECK: }
 //
 // CHECK-LABEL: define {{.*}} { ptr, ptr, ptr } @"$s7amethodTA"
-// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX:.*]], ptr swiftself %[[SELF:.*]], ptr noalias nocapture swifterror dereferenceable([[ERROR_SIZE]]) %[[ERRORPTR:.*]])
+// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX:.*]], ptr swiftself %[[SELF:.*]], ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable([[ERROR_SIZE]]) %[[ERRORPTR:.*]])
 // CHECK: entry:
 // CHECK:   %[[SELFPTR:.*]] = alloca ptr
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s7amethodTA.Frame", ptr %[[SPILL]], i32 0, i32 0
 // CHECK:   store ptr %[[SELF]], ptr %[[SELFPTR]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   store ptr null, ptr %[[ERRORPTR]]
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr, ptr } @amethod(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr noalias nocapture swiftself dereferenceable([[SELF_SIZE]]) %[[SELFPTR]], ptr noalias nocapture swifterror dereferenceable([[ERROR_SIZE]]) %[[ERRORPTR]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, ptr, ptr } @amethod(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable([[SELF_SIZE]]) %[[SELFPTR]], ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable([[ERROR_SIZE]]) %[[ERRORPTR]])
 // CHECK:   %[[ERRORVAL:.*]] = load ptr, ptr %[[ERRORPTR]]
 // CHECK:   %[[RESUME0:.*]] = extractvalue { ptr, ptr, ptr } %[[YIELD_PAIR]], 0
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s7amethodTA.Frame", ptr %[[SPILL]], i32 0, i32 1
@@ -2109,7 +2109,7 @@ entry(%a : $*A2<A3>):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s7amethodTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   store ptr %[[ERRORVAL]], ptr %[[ERRORPTR]]
 // CHECK:   call void @free(ptr %[[FRAME]])
@@ -2118,7 +2118,7 @@ entry(%a : $*A2<A3>):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s7amethodTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   store ptr %[[ERRORVAL]], ptr %[[ERRORPTR]]
 // CHECK:   call void @free(ptr %[[FRAME]])
@@ -2137,10 +2137,10 @@ bb0(%0 : $*A2<A3>):
 }
 
 // CHECK-LABEL: define {{.*}} { ptr, ptr } @partial_apply_callee_guaranteed_indirect_guaranteed_class_pair_param
-// CHECK-SAME: (ptr noalias nocapture dereferenceable([[ARG_SIZE:(8|16)]]) %[[ARG:.*]])
+// CHECK-SAME: (ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[ARG_SIZE:(8|16)]]) %[[ARG:.*]])
 // CHECK: entry:
 // CHECK:   %[[BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata
-// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   call void @llvm.memcpy.p0.p0.{{i32|i64}}(ptr align {{4|8}} %[[BOXPTR]], ptr align {{4|8}} %[[ARG]], {{i32|i64}} [[ARG_SIZE]], i1 false)
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}{{.*}}", ptr undef }, ptr %[[BOX]], 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
@@ -2153,10 +2153,10 @@ bb0(%0 : $*A2<A3>):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK:   %[[PA_ARG:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %T18partial_apply_coro14SwiftClassPairV }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_ARG:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[PA_ARG]])
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_guaranteed_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[PA_ARG]], [[ARG_TYPE]] %[[ARG0]], ptr noalias nocapture dereferenceable({{8|16}}) %[[PA_CTX]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_guaranteed_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[PA_ARG]], [[ARG_TYPE]] %[[ARG0]], ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{8|16}}) %[[PA_CTX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}.Frame", ptr %[[SPILL]], i32 0, i32 1
 // CHECK:   store ptr %[[RESUME]], ptr %[[SPILL2]],
@@ -2176,7 +2176,7 @@ bb0(%0 : $*A2<A3>):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -2184,7 +2184,7 @@ bb0(%0 : $*A2<A3>):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -2201,13 +2201,13 @@ bb0(%x : $*SwiftClassPair):
 sil public_external @use_closure2 : $@yield_once @convention(thin) (@noescape @yield_once @callee_guaranteed (Int) -> (@yields Int)) -> (@yields Int)
 
 // CHECK-LABEL: define {{.*}} @partial_apply_stack_callee_guaranteed_indirect_guaranteed_class_pair_param
-// CHECK-SAME: (ptr noalias nocapture dereferenceable([[ARG_SIZE:(8|16)]]) %[[ARG:.*]])
+// CHECK-SAME: (ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[ARG_SIZE:(8|16)]]) %[[ARG:.*]])
 // CHECK: entry:
 // CHECK:   %[[CTX:.*]] = alloca [[[BUFFER_SIZE]] x i8]
 // CHECK:   %[[BOX:.*]] = alloca i8
-// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   store ptr %[[ARG]], ptr %[[BOXPTR]]
-// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
+// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[RES_TYPE:(i32|i64)]] } @use_closure2(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTXPTR]], ptr @"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}{{.*}}", ptr %[[BOX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[RES_TYPE]] } %[[YIELD_PAIR]], 0
@@ -2224,11 +2224,11 @@ sil public_external @use_closure2 : $@yield_once @convention(thin) (@noescape @y
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[PA_ARG:.*]] = load ptr, ptr %[[PA_CTX]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_guaranteed_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias nocapture dereferenceable({{8|16}}) %[[PA_ARG]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_guaranteed_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{8|16}}) %[[PA_ARG]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}.Frame", ptr %[[SPILL]], i32 0, i32 1
 // CHECK:   store ptr %[[RESUME]], ptr %[[SPILL2]]
@@ -2248,7 +2248,7 @@ sil public_external @use_closure2 : $@yield_once @convention(thin) (@noescape @y
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -2256,7 +2256,7 @@ sil public_external @use_closure2 : $@yield_once @convention(thin) (@noescape @y
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s45indirect_guaranteed_captured_class_pair_paramTA.{{[0-9]+}}.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -2276,7 +2276,7 @@ bb0(%x : $*SwiftClassPair):
 
 // CHECK-32-LABEL: define {{.*}} { ptr, i32 } @indirect_in_captured_class_pair_param
 // CHECK-64-LABEL: define {{.*}} { ptr, i64 } @indirect_in_captured_class_pair_param
-// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, [[ARG_TYPE:(i32|i64)]] %{{.*}}, ptr noalias nocapture dereferenceable([[PAIR_SIZE:(8|16)]]) %{{.*}})
+// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, [[ARG_TYPE:(i32|i64)]] %{{.*}}, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE:(8|16)]]) %{{.*}})
 sil public @indirect_in_captured_class_pair_param : $@yield_once @convention(thin) (Int, @in_guaranteed SwiftClassPair) -> (@yields Int) {
 entry(%i : $Int, %p : $*SwiftClassPair):
   %0 = builtin "int_trap"() : $Never
@@ -2284,13 +2284,13 @@ entry(%i : $Int, %p : $*SwiftClassPair):
 }
 
 // CHECK-LABEL: define {{.*}} void @partial_apply_stack_callee_guaranteed_indirect_in_class_pair_param
-// CHECK-SAME: (ptr noalias nocapture dereferenceable([[PAIR_SIZE]]) %[[ARG:.*]])
+// CHECK-SAME: (ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE]]) %[[ARG:.*]])
 // CHECK: entry:
 // CHECK:   %[[CTX:.*]] = alloca [[[BUFFER_SIZE]] x i8],
 // CHECK:   %[[BOX:.*]] = alloca i8
-// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   store ptr %[[ARG]], ptr %[[BOXPTR]]
-// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
+// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @use_closure2(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTXPTR]], ptr @"$s37indirect_in_captured_class_pair_paramTA{{.*}}", ptr %[[BOX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
@@ -2308,11 +2308,11 @@ entry(%i : $Int, %p : $*SwiftClassPair):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s37indirect_in_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[PA_ARG:.*]] = load ptr, ptr %[[PA_CTX]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_in_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias nocapture dereferenceable([[PAIR_SIZE]]) %[[PA_ARG]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_in_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE]]) %[[PA_ARG]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s37indirect_in_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 1
 // CHECK:   store ptr %[[RESUME]], ptr %[[SPILL2]]
@@ -2332,7 +2332,7 @@ entry(%i : $Int, %p : $*SwiftClassPair):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s37indirect_in_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -2340,7 +2340,7 @@ entry(%i : $Int, %p : $*SwiftClassPair):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1]] = getelementptr inbounds %"$s37indirect_in_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -2367,7 +2367,7 @@ bb0(%x : $*SwiftClassPair):
 // CHECK-arm64e: [[VWTABLEADDR:%.*]] = ptrtoint ptr [[VWT_PTR]] to i64
 // CHECK-arm64e: [[VWTABLEAUTH:%.*]] = call i64 @llvm.ptrauth.auth(i64 [[VWTABLEADDR]], i32 2
 // CHECK-arm64e: [[VWTABLE:%.*]] = inttoptr i64 [[VWTABLEAUTH]] to ptr
-// CHECK:   [[FLAGS_PTR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWTABLE]], i32 0, i32 10
+// CHECK:   [[FLAGS_PTR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWTABLE]], i32 0, i32 10
 
 sil public_external @closure : $@yield_once @convention(thin) (@in_guaranteed ResilientInt, @guaranteed SwiftClass) -> (@yields @in ResilientInt)
 sil @test_initial_offset : $@convention(thin) (@in ResilientInt, @guaranteed SwiftClass) -> () {
@@ -2477,7 +2477,7 @@ entry:
 
 // CHECK-32: define {{.*}} { ptr, i32 } @indirect_in_constant_captured_class_pair_param
 // CHECK-64: define {{.*}} { ptr, i64 } @indirect_in_constant_captured_class_pair_param
-// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, [[ARG_TYPE:(i32|i64)]] %1, ptr noalias nocapture dereferenceable([[PAIR_SIZE:(8|16)]]) %2)
+// CHECK-SAME: (ptr noalias dereferenceable([[BUFFER_SIZE:(16|32)]]) %0, [[ARG_TYPE:(i32|i64)]] %1, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE:(8|16)]]) %2)
 sil public @indirect_in_constant_captured_class_pair_param : $@yield_once @convention(thin) (Int, @in_guaranteed SwiftClassPair) -> (@yields Int) {
 entry(%i : $Int, %ic : $*SwiftClassPair):
   %0 = builtin "int_trap"() : $Never
@@ -2485,13 +2485,13 @@ entry(%i : $Int, %ic : $*SwiftClassPair):
 }
 
 // CHECK-LABEL: define {{.*}} void @partial_apply_stack_callee_guaranteed_indirect_in_constant_class_pair_param
-// CHECK-SAME: (ptr noalias nocapture dereferenceable([[PAIR_SIZE]]) %[[ARG:.*]])
+// CHECK-SAME: (ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE]]) %[[ARG:.*]])
 // CHECK: entry:
 // CHECK:   %[[CTX:.*]] = alloca [[[BUFFER_SIZE]] x i8]
 // CHECK:   %[[BOX:.*]] = alloca i8
-// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr %[[BOX]], i32 0, i32 1
+// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr %[[BOX]], i32 0, i32 1
 // CHECK:   store ptr %[[ARG]], ptr %[[BOXPTR]]
-// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
+// CHECK:   %[[CTXPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[CTX]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[CTXPTR]])
 // CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @use_closure2(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTXPTR]], ptr @"$s46indirect_in_constant_captured_class_pair_paramTA{{.*}}", ptr %[[BOX]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
@@ -2509,11 +2509,11 @@ entry(%i : $Int, %ic : $*SwiftClassPair):
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s46indirect_in_constant_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
 // CHECK:   %[[PA_ARG:.*]] = load ptr, ptr %[[PA_CTX]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_in_constant_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias nocapture dereferenceable([[PAIR_SIZE]]) %[[PA_ARG]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc { ptr, [[ARG_TYPE]] } @indirect_in_constant_captured_class_pair_param(ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG0]], ptr noalias {{(nocapture|captures\(none\))}} dereferenceable([[PAIR_SIZE]]) %[[PA_ARG]])
 // CHECK:   %[[RESUME:.*]] = extractvalue { ptr, [[ARG_TYPE]] } %[[YIELD_PAIR]], 0
 // CHECK:   %[[SPILL2:.*]] = getelementptr inbounds %"$s46indirect_in_constant_captured_class_pair_paramTA.Frame", ptr %[[SPILL]], i32 0, i32 1
 // CHECK:   store ptr %[[RESUME]], ptr %[[SPILL2]]
@@ -2533,7 +2533,7 @@ entry(%i : $Int, %ic : $*SwiftClassPair):
 // CHECK-LABEL: unwind:
 // CHECK:   %[[RESUME_ADDR0:.*]] = getelementptr inbounds %"$s46indirect_in_constant_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME0:.*]] = load ptr, ptr %[[RESUME_ADDR0]]
-// CHECK:   %[[CTX0:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX0:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME0]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX0]], i1 true)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   unreachable
@@ -2541,7 +2541,7 @@ entry(%i : $Int, %ic : $*SwiftClassPair):
 // CHECK-LABEL: resume:
 // CHECK:   %[[RESUME_ADDR1:.*]] = getelementptr inbounds %"$s46indirect_in_constant_captured_class_pair_paramTA.Frame", ptr %[[FRAME]], i32 0, i32 1
 // CHECK:   %[[RESUME1:.*]] = load ptr, ptr %[[RESUME_ADDR1]]
-// CHECK:   %[[CTX1:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
+// CHECK:   %[[CTX1:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAMEPTR]], i32 0, i32 0
 // CHECK:   call swiftcc void %[[RESUME1]](ptr noalias dereferenceable([[BUFFER_SIZE]]) %[[CTX1]], i1 false)
 // CHECK:   call void @free(ptr %[[FRAME]])
 // CHECK:   ret void
@@ -2571,26 +2571,26 @@ bb0(%thick : $@callee_guaranteed @yield_once @convention(thick) (Int64, Int32) -
 // CHECK-SAME: ([[ARG_TYPE:(i64|i32)]] %[[ARG:.*]])
 // CHECK: entry:
 // CHECK:   %[[BOX:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata
-// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSi }>, ptr %1, i32 0, i32 1
-// CHECK:   %[[ARGPTR:.*]] = getelementptr inbounds %TSi, ptr %2, i32 0, i32 0
+// CHECK:   %[[BOXPTR:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSi }>, ptr %1, i32 0, i32 1
+// CHECK:   %[[ARGPTR:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %2, i32 0, i32 0
 // CHECK:   store [[ARG_TYPE]] %[[ARG]], ptr %[[ARGPTR]]
 // CHECK:   %[[RET:.*]] = insertvalue { ptr, ptr } { ptr @"$s16external_closureTA{{.*}}", ptr undef }, ptr %[[BOX]], 1
 // CHECK:   ret { ptr, ptr } %[[RET]]
 // CHECK: }
 //
 // CHECK-LABEL: define {{.*}} ptr @"$s16external_closureTA"
-// CHECK-SAME: (ptr noalias {{.*}} %[[CTX:.*]], [[ARG_TYPE]] %[[ARG1:.*]], ptr swiftself %[[PA_CTX_BOX:.*]], ptr noalias nocapture swifterror {{.*}} %[[ERROR:.*]])
+// CHECK-SAME: (ptr noalias {{.*}} %[[CTX:.*]], [[ARG_TYPE]] %[[ARG1:.*]], ptr swiftself %[[PA_CTX_BOX:.*]], ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} {{.*}} %[[ERROR:.*]])
 // CHECK: entry:
 // CHECK:   %[[SPILL:.*]] = call ptr @malloc
 // CHECK:   store ptr %[[SPILL]], ptr %[[CTX]]
 // CHECK:   %[[FRAME:.*]] = getelementptr inbounds %"$s16external_closureTA.Frame", ptr %[[SPILL]], i32 0, i32 0
-// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds <{ %swift.refcounted, %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
-// CHECK:   %[[PA_ARG:.*]] = getelementptr inbounds %TSi, ptr %[[PA_CTX]], i32 0, i32 0
+// CHECK:   %[[PA_CTX:.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, %TSi }>, ptr %[[PA_CTX_BOX]], i32 0, i32 1
+// CHECK:   %[[PA_ARG:.*]] = getelementptr inbounds{{.*}} %TSi, ptr %[[PA_CTX]], i32 0, i32 0
 // CHECK:   %[[ARG2:.*]] = load [[ARG_TYPE]], ptr %[[PA_ARG]]
-// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
+// CHECK:   %[[FRAMEPTR:.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr %[[FRAME]], i32 0, i32 0
 // CHECK:   call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr %[[FRAMEPTR]])
 // CHECK:   store ptr null, ptr %[[ERROR]]
-// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc ptr @external_closure(ptr noalias {{.*}} %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG1]], [[ARG_TYPE]] %[[ARG2]], ptr swiftself undef, ptr noalias nocapture swifterror {{.*}} %[[ERROR]])
+// CHECK:   %[[YIELD_PAIR:.*]] = call swiftcc ptr @external_closure(ptr noalias {{.*}} %[[FRAMEPTR]], [[ARG_TYPE]] %[[ARG1]], [[ARG_TYPE]] %[[ARG2]], ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} {{.*}} %[[ERROR]])
 // CHECK:   %[[SPILL1:.*]] = getelementptr inbounds %"$s16external_closureTA.Frame", ptr %[[SPILL]], i32 0, i32 1
 // CHECK:   store ptr %[[YIELD_PAIR]], ptr %[[SPILL1]]
 // CHECK:   %[[ERRORVAL:.*]] = load ptr, ptr %[[ERROR]]
diff --git a/test/IRGen/partial_apply_forwarder.sil b/test/IRGen/partial_apply_forwarder.sil
index 8f1af66496687..ae8a0f604372b 100644
--- a/test/IRGen/partial_apply_forwarder.sil
+++ b/test/IRGen/partial_apply_forwarder.sil
@@ -170,15 +170,15 @@ sil hidden_external @takingQAndS : $@convention(thin) <τ_0_0 where  τ_0_0 : Q>
 // CHECK:   [[WBREF:%.*]] = call noalias ptr @swift_allocObject(ptr [[WBTY]]
 // CHECK:   [[CONTEXT0:%.*]] = call noalias ptr @swift_allocObject
 
-// CHECK:   [[WITNESS_ADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr [[CONTEXT0]], i32 0, i32 {{(1|2)}}
+// CHECK:   [[WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr [[CONTEXT0]], i32 0, i32 {{(1|2)}}
 // CHECK:   [[WITNESS:%.*]] = call ptr @swift_getWitnessTable(ptr @"$s23partial_apply_forwarder12BaseProducerVyxGAA1QAAMc", ptr [[BPTY]], ptr undef)
 // CHECK:   store ptr [[WITNESS]], ptr [[WITNESS_ADDR]]
 
-// CHECK:   [[SADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr [[CONTEXT0]], i32 0, i32 {{(2|3)}}
-// CHECK:   [[XADDR:%.*]] = getelementptr inbounds %T23partial_apply_forwarder1SV, ptr [[SADDR]], i32 0, i32 0
+// CHECK:   [[SADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr [[CONTEXT0]], i32 0, i32 {{(2|3)}}
+// CHECK:   [[XADDR:%.*]] = getelementptr inbounds{{.*}} %T23partial_apply_forwarder1SV, ptr [[SADDR]], i32 0, i32 0
 // CHECK:   store i64 %1, ptr [[XADDR]]
 
-// CHECK:   [[WBADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr [[CONTEXT0]], i32 0, i32 {{(3|4)}}
+// CHECK:   [[WBADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr [[CONTEXT0]], i32 0, i32 {{(3|4)}}
 // CHECK:   store ptr [[WBREF]], ptr [[WBADDR]]
 // CHECK:   [[CLOSURE:%.*]] = insertvalue { ptr, ptr } { ptr @"$s11takingQAndSTA{{(\.ptrauth)?}}", ptr undef }, ptr [[CONTEXT0]], 1
 // CHECK:   ret { ptr, ptr } [[CLOSURE]]
@@ -186,14 +186,14 @@ sil hidden_external @takingQAndS : $@convention(thin) <τ_0_0 where  τ_0_0 : Q>
 // CHECK-LABEL: define internal swiftcc void @"$s11takingQAndSTA"(ptr swiftself %0)
 // CHECK: entry:
 
-// CHECK:   [[WITNESS_ADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr %0, i32 0, i32 {{(1|2)}}
+// CHECK:   [[WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr %0, i32 0, i32 {{(1|2)}}
 // CHECK:   [[WITNESS:%.*]] = load ptr, ptr [[WITNESS_ADDR]]
 
-// CHECK:   [[SADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr %0, i32 0, i32 {{(2|3)}}
-// CHECK:   [[XADDR:%.*]] = getelementptr inbounds %T23partial_apply_forwarder1SV, ptr [[SADDR]], i32 0, i32 0
+// CHECK:   [[SADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr %0, i32 0, i32 {{(2|3)}}
+// CHECK:   [[XADDR:%.*]] = getelementptr inbounds{{.*}} %T23partial_apply_forwarder1SV, ptr [[SADDR]], i32 0, i32 0
 // CHECK:   [[X:%.*]] = load i64, ptr [[XADDR]]
 
-// CHECK:   [[WBADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr %0, i32 0, i32 {{(3|4)}}
+// CHECK:   [[WBADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted,{{.*}} %T23partial_apply_forwarder1SV, ptr }>, ptr %0, i32 0, i32 {{(3|4)}}
 // CHECK:   [[WB:%.*]] = load ptr, ptr [[WBADDR]]
 // CHECK:   call ptr @swift_retain(ptr returned [[WB]])
 // CHECK:   [[TY:%.*]] = load ptr, ptr [[WB]]
diff --git a/test/IRGen/partial_apply_generic.swift b/test/IRGen/partial_apply_generic.swift
index 20796c87214f0..f6123c234b9b6 100644
--- a/test/IRGen/partial_apply_generic.swift
+++ b/test/IRGen/partial_apply_generic.swift
@@ -37,7 +37,7 @@ var x = seq ~> split
 // Indirect return
 //
 
-// CHECK-LABEL: define internal swiftcc { ptr, ptr } @"$s21partial_apply_generic5split{{[_0-9a-zA-Z]*}}FTA"(ptr noalias nocapture %0, ptr swiftself %1)
+// CHECK-LABEL: define internal swiftcc { ptr, ptr } @"$s21partial_apply_generic5split{{[_0-9a-zA-Z]*}}FTA"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftself %1)
 // CHECK:         tail call swiftcc { ptr, ptr } @"$s21partial_apply_generic5split{{[_0-9a-zA-Z]*}}F"(ptr noalias %0,
 
 struct HugeStruct { var a, b, c, d: Int }
diff --git a/test/IRGen/partial_apply_objc.sil b/test/IRGen/partial_apply_objc.sil
index 8d538f79ad261..f777edfec7c57 100644
--- a/test/IRGen/partial_apply_objc.sil
+++ b/test/IRGen/partial_apply_objc.sil
@@ -51,22 +51,22 @@ bb0(%0 : $ObjCClass):
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @indirect_partial_apply(ptr %0, ptr %1, i64 %2) {{.*}} {
 // CHECK: entry:
 // CHECK:   [[OBJ:%.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata, i32 0, i32 2), i64 40, i64 7)
-// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds [[DATA_TYPE:<{ %swift.refcounted, i64, ptr, ptr }>]], ptr [[OBJ]], i32 0, i32 1
+// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds{{.*}} [[DATA_TYPE:<{ %swift.refcounted, i64, ptr, ptr }>]], ptr [[OBJ]], i32 0, i32 1
 // CHECK:   store i64 %2, ptr [[X_ADDR]], align 8
-// CHECK:   [[CONTEXT_ADDR:%.*]] = getelementptr inbounds [[DATA_TYPE]], ptr [[OBJ]], i32 0, i32 2
+// CHECK:   [[CONTEXT_ADDR:%.*]] = getelementptr inbounds{{.*}} [[DATA_TYPE]], ptr [[OBJ]], i32 0, i32 2
 // CHECK:   store ptr %1, ptr [[CONTEXT_ADDR]], align 8
-// CHECK:   [[FN_ADDR:%.*]] = getelementptr inbounds [[DATA_TYPE]], ptr [[OBJ]], i32 0, i32 3
+// CHECK:   [[FN_ADDR:%.*]] = getelementptr inbounds{{.*}} [[DATA_TYPE]], ptr [[OBJ]], i32 0, i32 3
 // CHECK:   store ptr %0, ptr [[FN_ADDR]], align 8
 // CHECK:   [[RET:%.*]] = insertvalue { ptr, ptr } { ptr [[INDIRECT_PARTIAL_APPLY_STUB:@"\$sTA[A-Za-z0-9_]*"]], ptr undef }, ptr [[OBJ]], 1
 // CHECK:   ret { ptr, ptr } [[RET]]
 // CHECK: }
 // CHECK: define internal swiftcc void [[INDIRECT_PARTIAL_APPLY_STUB]](ptr swiftself %0) {{.*}} {
 // CHECK: entry:
-// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds [[DATA_TYPE]], ptr %0, i32 0, i32 1
+// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds{{.*}} [[DATA_TYPE]], ptr %0, i32 0, i32 1
 // CHECK:   [[X:%.*]] = load i64, ptr [[X_ADDR]], align 8
-// CHECK:   [[CONTEXT_ADDR:%.*]] = getelementptr inbounds [[DATA_TYPE]], ptr %0, i32 0, i32 2
+// CHECK:   [[CONTEXT_ADDR:%.*]] = getelementptr inbounds{{.*}} [[DATA_TYPE]], ptr %0, i32 0, i32 2
 // CHECK:   [[CONTEXT:%.*]] = load ptr, ptr [[CONTEXT_ADDR]], align 8
-// CHECK:   [[FN_ADDR:%.*]] = getelementptr inbounds [[DATA_TYPE]], ptr %0, i32 0, i32 3
+// CHECK:   [[FN_ADDR:%.*]] = getelementptr inbounds{{.*}} [[DATA_TYPE]], ptr %0, i32 0, i32 3
 // CHECK:   [[FN_PTR:%.*]] = load ptr, ptr [[FN_ADDR]], align 8
 // CHECK:   tail call swiftcc void [[FN_PTR]](i64 [[X]], ptr swiftself [[CONTEXT]])
 // CHECK:   ret void
@@ -81,7 +81,7 @@ entry(%f : $@callee_owned (Builtin.Word) -> (), %x : $Builtin.Word):
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @objc_partial_apply(ptr %0) {{.*}} {
 // CHECK: entry:
 // CHECK:   [[OBJ:%.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%swift.full_boxmetadata, ptr @metadata.2, i32 0, i32 2), i64 24, i64 7)
-// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds [[DATA_TYPE:<{ %swift.refcounted, ptr }>]], ptr [[OBJ]], i32 0, i32 1
+// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds{{.*}} [[DATA_TYPE:<{ %swift.refcounted, ptr }>]], ptr [[OBJ]], i32 0, i32 1
 // CHECK:   store ptr %0, ptr [[X_ADDR]], align 8
 // CHECK:   [[RET:%.*]] = insertvalue { ptr, ptr } { ptr [[OBJC_PARTIAL_APPLY_STUB:@"\$sTa[A-Za-z0-9_]*"]], ptr undef }, ptr [[OBJ]], 1
 // CHECK:   ret { ptr, ptr } [[RET]]
@@ -90,7 +90,7 @@ entry(%f : $@callee_owned (Builtin.Word) -> (), %x : $Builtin.Word):
 // CHECK: entry:
 // CHECK-NOT: swift_retain
 // CHECK-NOT: swift_retain
-// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds [[DATA_TYPE]], ptr %1, i32 0, i32 1
+// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds{{.*}} [[DATA_TYPE]], ptr %1, i32 0, i32 1
 // CHECK-NOT: swift_retain
 // CHECK:   [[SELF:%.*]] = load ptr, ptr [[X_ADDR]], align 8
 // CHECK-NOT: swift_retain
@@ -109,16 +109,16 @@ entry(%c : $ObjCClass):
 
 // CHECK-LABEL: define{{.*}} { ptr, ptr } @objc_partial_apply_indirect_sil_argument(ptr %0) {{.*}}
 // CHECK:  [[CTX:%.*]] = call noalias ptr @swift_allocObject
-// CHECK:  [[SELF_ADDR:%.*]] = getelementptr inbounds [[CTXTYPE:<{ %swift.refcounted, ptr }>]], ptr [[CTX]], i32 0, i32 1
+// CHECK:  [[SELF_ADDR:%.*]] = getelementptr inbounds{{.*}} [[CTXTYPE:<{ %swift.refcounted, ptr }>]], ptr [[CTX]], i32 0, i32 1
 // CHECK:  store ptr %0, ptr [[SELF_ADDR]]
 // CHECK:  [[CLOSURE:%.*]] = insertvalue { ptr, ptr } { ptr [[OBJC_PARTIAL_APPLY_STUB2:@"\$sTa[A-Za-z0-9_.]*"]], ptr undef }, ptr [[CTX]], 1
 // CHECK:  ret { ptr, ptr } [[CLOSURE]]
 // CHECK:}
 // CHECK: define internal swiftcc void [[OBJC_PARTIAL_APPLY_STUB2]](double %0, double %1, double %2, double %3, ptr
 // CHECK:  [[TMP:%.*]] = alloca %TSo6NSRectV
-// CHECK:  [[ORIGIN:%.*]] = getelementptr inbounds %TSo6NSRectV, ptr [[TMP]]
-// CHECK:  [[ORIGINX:%.*]] = getelementptr inbounds %TSo7NSPointV, ptr [[ORIGIN]]
-// CHECK:  [[ORIGINXVAL:%*]] = getelementptr inbounds %TSd, ptr [[ORIGINX]]
+// CHECK:  [[ORIGIN:%.*]] = getelementptr inbounds{{.*}} %TSo6NSRectV, ptr [[TMP]]
+// CHECK:  [[ORIGINX:%.*]] = getelementptr inbounds{{.*}} %TSo7NSPointV, ptr [[ORIGIN]]
+// CHECK:  [[ORIGINXVAL:%*]] = getelementptr inbounds{{.*}} %TSd, ptr [[ORIGINX]]
 // CHECK:  store double %0, ptr [[ORIGINXVAL]]
 sil @objc_partial_apply_indirect_sil_argument : $@convention(thin) (ObjCClass) -> @callee_owned (NSRect) -> () {
 entry(%c : $ObjCClass):
@@ -130,7 +130,7 @@ entry(%c : $ObjCClass):
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @objc_partial_apply_consumes_self(ptr %0) {{.*}} {
 // CHECK:         insertvalue {{.*}} [[OBJC_CONSUMES_SELF_PARTIAL_APPLY_STUB:@"\$sTa[A-Za-z0-9_.]*"]]
 // CHECK: define internal swiftcc ptr [[OBJC_CONSUMES_SELF_PARTIAL_APPLY_STUB]](ptr swiftself %0) {{.*}} {
-// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds [[DATA_TYPE:<{ %swift.refcounted, ptr }>]], ptr %0, i32 0, i32 1
+// CHECK:   [[X_ADDR:%.*]] = getelementptr inbounds{{.*}} [[DATA_TYPE:<{ %swift.refcounted, ptr }>]], ptr %0, i32 0, i32 1
 // CHECK:   [[SELF:%.*]] = load ptr, ptr [[X_ADDR]], align 8
 // CHECK:   call ptr @llvm.objc.retain(ptr [[SELF]])
 // CHECK:   [[CMD:%.*]] = load ptr, ptr @"\01L_selector(fakeInitFamily)", align 8
@@ -190,11 +190,11 @@ entry(%c : $Gizmo):
 // CHECK: define internal swiftcc void @"$sTa.17"(i64 %0, i64 %1, i64 %2, ptr swiftself %3)
 // CHECK: [[TMPCOERCE:%.*]] = alloca { i64, i64, i64 }
 // CHECK: [[INDIRECTTEMP:%.*]] = alloca %TSo3FobV
-// CHECK: [[ADDR:%.*]] = getelementptr inbounds { i64, i64, i64 }, ptr [[TMPCOERCE]], i32 0, i32 0
+// CHECK: [[ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64 }, ptr [[TMPCOERCE]], i32 0, i32 0
 // CHECK:  store i64 %0, ptr [[ADDR]]
-// CHECK:  [[ADDR:%.]] = getelementptr inbounds { i64, i64, i64 }, ptr [[TMPCOERCE]], i32 0, i32 1
+// CHECK:  [[ADDR:%.]] = getelementptr inbounds{{.*}} { i64, i64, i64 }, ptr [[TMPCOERCE]], i32 0, i32 1
 // CHECK:  store i64 %1, ptr [[ADDR]]
-// CHECK:  [[ADDR:%.*]] = getelementptr inbounds { i64, i64, i64 }, ptr [[TMPCOERCE]], i32 0, i32 2
+// CHECK:  [[ADDR:%.*]] = getelementptr inbounds{{.*}} { i64, i64, i64 }, ptr [[TMPCOERCE]], i32 0, i32 2
 // CHECK:  store i64 %2, ptr [[ADDR]]
 // CHECK:  load i64
 // CHECK:  load i32
diff --git a/test/IRGen/pic.swift b/test/IRGen/pic.swift
index db29b347255d3..b5160b2bfd701 100644
--- a/test/IRGen/pic.swift
+++ b/test/IRGen/pic.swift
@@ -2,7 +2,7 @@
 // platforms.
 
 // https://github.com/apple/swift/issues/54619
-// XFAIL: OS=linux-android, CPU=aarch64
+// XFAIL: OS=linux-android && CPU=aarch64
 // UNSUPPORTED: OS=linux-gnu, CPU=wasm32
 
 // RUN: %target-swift-frontend %s -module-name main -S -o - | %FileCheck -check-prefix=%target-cpu -check-prefix=%target-cpu-%target-sdk-name %s
diff --git a/test/IRGen/pre_specialize.swift b/test/IRGen/pre_specialize.swift
index b959a4833cab3..992c37a18358c 100644
--- a/test/IRGen/pre_specialize.swift
+++ b/test/IRGen/pre_specialize.swift
@@ -42,12 +42,11 @@
 // specialized InternalThing.computedX.getter
 // CHECK-A-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc [[INT]] @"$s1A13InternalThingV9computedXxvgSi_Ts5"([[INT]]{{( returned)?}} %0)
 // specialized InternalThing.computedX.setter
-// CHECK-A-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s1A13InternalThingV9computedXxvsSi_Ts5"([[INT]] %0, ptr nocapture swiftself {{(writeonly )?}}dereferenceable({{(4|8)}}) %1)
-
+// CHECK-A-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s1A13InternalThingV9computedXxvsSi_Ts5"([[INT]] %0, ptr{{( nocapture)?}} swiftself {{(writeonly )?}}{{(captures\(none\) )?}}dereferenceable({{(4|8)}}){{.*}} %1)
 // specialized InternalThing.subscript.getter
 // CHECK-A-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc [[INT]] @"$s1A13InternalThingVyxSicigSi_Ts5"([[INT]] %0, [[INT]]{{( returned)?}} %1)
 // specialized InternalThing.subscript.setter
-// CHECK-A-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s1A13InternalThingVyxSicisSi_Ts5"([[INT]] %0, [[INT]] %1, ptr nocapture swiftself {{(writeonly )?}}dereferenceable({{(4|8)}}) %2)
+// CHECK-A-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s1A13InternalThingVyxSicisSi_Ts5"([[INT]] %0, [[INT]] %1, ptr{{( nocapture)?}} swiftself {{(writeonly )?}}{{(captures\(none\) )?}}dereferenceable({{(4|8)}}){{.*}} %2)
 
 // specialized InternalRef.compute()
 // CHECK-A-FRAG-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc [[INT:(i64|i32)]] @"$s1A11InternalRefC7computexyFAA09ResilientA10BoxedThingVySiG_Ts5"
@@ -76,13 +75,13 @@
 // CHECK-B-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @"$s1A13InternalThingV9computedXxvg1B07AnotherB0C_Ts5"(ptr{{( returned)?}} %0)
 
 // specialized InternalThing.computedX.setter
-// CHECK-B-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s1A13InternalThingV9computedXxvs1B07AnotherB0C_Ts5"(ptr %0, ptr nocapture swiftself dereferenceable({{(4|8)}}) %1)
+// CHECK-B-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s1A13InternalThingV9computedXxvs1B07AnotherB0C_Ts5"(ptr %0, ptr{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{(4|8)}}) %1)
 
 // specialized InternalThing.subscript.getter
 // CHECK-B-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @"$s1A13InternalThingVyxSicig1B07AnotherB0C_Ts5"([[INT:(i64|i32)]] %0, ptr{{( returned)?}} %1)
 
 // specialized InternalThing.subscript.setter
-// CHECK-B-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s1A13InternalThingVyxSicis1B07AnotherB0C_Ts5"(ptr %0, [[INT]] %1, ptr nocapture swiftself dereferenceable({{(4|8)}}) %2)
+// CHECK-B-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s1A13InternalThingVyxSicis1B07AnotherB0C_Ts5"(ptr %0, [[INT]] %1, ptr{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{(4|8)}}) %2)
 
 // specialized InternalRef.compute()
 // CHECK-B-DAG: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @"$s1A11InternalRefC7computexyF1B12AnotherThingC_Ts5
diff --git a/test/IRGen/prespecialized-metadata/class-fileprivate-inmodule-1argument-1distinct_use-1st_argument_generic_class-1argument.swift b/test/IRGen/prespecialized-metadata/class-fileprivate-inmodule-1argument-1distinct_use-1st_argument_generic_class-1argument.swift
index 1d2d0bee8e541..491b11e2d4230 100644
--- a/test/IRGen/prespecialized-metadata/class-fileprivate-inmodule-1argument-1distinct_use-1st_argument_generic_class-1argument.swift
+++ b/test/IRGen/prespecialized-metadata/class-fileprivate-inmodule-1argument-1distinct_use-1st_argument_generic_class-1argument.swift
@@ -106,8 +106,8 @@
 //         CHECK-SAME:   ptr
 //         CHECK-SAME:   ptr, 
 //                   :   [[INT]], 
-//   CHECK-SAME-apple:   ptr, 
-// CHECK-SAME-unknown:   ptr, 
+//   CHECK-apple-SAME:   ptr, 
+// CHECK-unknown-SAME:   ptr, 
 //   CHECK-apple-SAME:   ptr, 
 //   CHECK-apple-SAME:   ptr, 
 //   CHECK-apple-SAME:   [[INT]], 
diff --git a/test/IRGen/prespecialized-metadata/class-inmodule-1argument-run.swift b/test/IRGen/prespecialized-metadata/class-inmodule-1argument-run.swift
index 11f31dff0dbe8..eae864378bfc5 100644
--- a/test/IRGen/prespecialized-metadata/class-inmodule-1argument-run.swift
+++ b/test/IRGen/prespecialized-metadata/class-inmodule-1argument-run.swift
@@ -44,29 +44,29 @@ func consume<T>(clazzType: MyGenericClazz<T>.Type) {
 
 
 public func doit() {
-  // CHECK: [[FLOAT_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<Float> @ 48
+  // CHECK: [[FLOAT_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<Float> @ [[@LINE+1]]
   consume(MyGenericClazz<Float>())
-  // CHECK: [[FLOAT_METADATA_ADDRESS]] MyGenericClazz<Float> @ 50
+  // CHECK: [[FLOAT_METADATA_ADDRESS]] MyGenericClazz<Float> @ [[@LINE+1]]
   consume(clazz: MyGenericClazz<Float>())
 
-  // CHECK: [[DOUBLE_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<Double> @ 53
+  // CHECK: [[DOUBLE_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<Double> @ [[@LINE+1]]
   consume(MyGenericClazz<Double>())
-  // CHECK: [[DOUBLE_METADATA_ADDRESS]] MyGenericClazz<Double> @ 55
+  // CHECK: [[DOUBLE_METADATA_ADDRESS]] MyGenericClazz<Double> @ [[@LINE+1]]
   consume(clazz: MyGenericClazz<Double>())
 
-  // CHECK: [[INT_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<Int> @ 58
+  // CHECK: [[INT_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<Int> @ [[@LINE+1]]
   consume(MyGenericClazz<Int>())
-  // CHECK: [[INT_METADATA_ADDRESS]] MyGenericClazz<Int> @ 60
+  // CHECK: [[INT_METADATA_ADDRESS]] MyGenericClazz<Int> @ [[@LINE+1]]
   consume(clazz: MyGenericClazz<Int>())
 
-  // CHECK: [[STRING_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<String> @ 63
+  // CHECK: [[STRING_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<String> @ [[@LINE+1]]
   consume(MyGenericClazz<String>())
-  // CHECK: [[STRING_METADATA_ADDRESS]] MyGenericClazz<String> @ 65
+  // CHECK: [[STRING_METADATA_ADDRESS]] MyGenericClazz<String> @ [[@LINE+1]]
   consume(clazz: MyGenericClazz<String>())
 
-  // CHECK: [[NESTED_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<MyGenericClazz<String>> @ 68
+  // CHECK: [[NESTED_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<MyGenericClazz<String>> @ [[@LINE+1]]
   consume(MyGenericClazz<MyGenericClazz<String>>())
-  // CHECK: [[NESTED_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<MyGenericClazz<String>> @ 70
+  // CHECK: [[NESTED_METADATA_ADDRESS:[0-9a-f]+]] MyGenericClazz<MyGenericClazz<String>> @ [[@LINE+1]]
   consume(clazz: MyGenericClazz<MyGenericClazz<String>>())
 
   // CHECK: [[FLOAT_METADATA_METATYPE_ADDRESS:[0-9a-f]+]] MyGenericClazz<Float>
diff --git a/test/IRGen/prespecialized-metadata/class-inmodule-2argument-1super-2argument-run.swift b/test/IRGen/prespecialized-metadata/class-inmodule-2argument-1super-2argument-run.swift
index 694cdc0bea195..3fb6eaac1cdec 100644
--- a/test/IRGen/prespecialized-metadata/class-inmodule-2argument-1super-2argument-run.swift
+++ b/test/IRGen/prespecialized-metadata/class-inmodule-2argument-1super-2argument-run.swift
@@ -61,20 +61,20 @@ func consume<Input, Output>(derived: MyWeakMutableInstanceMethodBox<Input,  Outp
 }
 
 func doit() {
-    // CHECK: [[SUPERCLASS_METADATA_INT_BOOL_ADDRESS:[0-9a-f]+]] WeakMutableInstanceMethodBox<Int, Bool> @ 65
+    // CHECK: [[SUPERCLASS_METADATA_INT_BOOL_ADDRESS:[0-9a-f]+]] WeakMutableInstanceMethodBox<Int, Bool> @ [[@LINE+1]]
     consume(WeakMutableInstanceMethodBox<Int, Bool>())
-    // CHECK: [[SUPERCLASS_METADATA_INT_BOOL_ADDRESS]] WeakMutableInstanceMethodBox<Int, Bool> @ 67
+    // CHECK: [[SUPERCLASS_METADATA_INT_BOOL_ADDRESS]] WeakMutableInstanceMethodBox<Int, Bool> @ [[@LINE+1]]
     consume(base: WeakMutableInstanceMethodBox<Int, Bool>())
-    // CHECK: [[SUPERCLASS_METADATA_DOUBLE_FLOAT_ADDRESS:[0-9a-f]+]] WeakMutableInstanceMethodBox<Double, Float> @ 69
+    // CHECK: [[SUPERCLASS_METADATA_DOUBLE_FLOAT_ADDRESS:[0-9a-f]+]] WeakMutableInstanceMethodBox<Double, Float> @ [[@LINE+1]]
     consume(WeakMutableInstanceMethodBox<Double, Float>())
-    // CHECK: [[SUPERCLASS_METADATA_DOUBLE_FLOAT_ADDRESS]] WeakMutableInstanceMethodBox<Double, Float> @ 71
+    // CHECK: [[SUPERCLASS_METADATA_DOUBLE_FLOAT_ADDRESS]] WeakMutableInstanceMethodBox<Double, Float> @ [[@LINE+1]]
     consume(base: WeakMutableInstanceMethodBox<Double, Float>())
 
-    // CHECK: [[SUBCLASS_METADATA_INT_BOOL_ADDRESS:[0-9a-f]+]] MyWeakMutableInstanceMethodBox<Int, Bool> @ 74
+    // CHECK: [[SUBCLASS_METADATA_INT_BOOL_ADDRESS:[0-9a-f]+]] MyWeakMutableInstanceMethodBox<Int, Bool> @ [[@LINE+1]]
     consume(MyWeakMutableInstanceMethodBox<Int, Bool>())
-    // CHECK: [[SUPERCLASS_METADATA_INT_BOOL_ADDRESS]] MyWeakMutableInstanceMethodBox<Int, Bool> @ 76
+    // CHECK: [[SUPERCLASS_METADATA_INT_BOOL_ADDRESS]] MyWeakMutableInstanceMethodBox<Int, Bool> @ [[@LINE+1]]
     consume(base: MyWeakMutableInstanceMethodBox<Int, Bool>())
-    // CHECK: [[SUBCLASS_METADATA_INT_BOOL_ADDRESS]] MyWeakMutableInstanceMethodBox<Int, Bool> @ 78
+    // CHECK: [[SUBCLASS_METADATA_INT_BOOL_ADDRESS]] MyWeakMutableInstanceMethodBox<Int, Bool> @ [[@LINE+1]]
     consume(derived: MyWeakMutableInstanceMethodBox<Int, Bool>())
 
     // CHECK: [[SUBCLASS_METADATA_DOUBLE_FLOAT_ADDRESS:[0-9a-f]+]] MyWeakMutableInstanceMethodBox<Double, Float>
diff --git a/test/IRGen/prespecialized-metadata/mpenum-ptrauth-vw.swift b/test/IRGen/prespecialized-metadata/mpenum-ptrauth-vw.swift
new file mode 100644
index 0000000000000..937b3fb08701e
--- /dev/null
+++ b/test/IRGen/prespecialized-metadata/mpenum-ptrauth-vw.swift
@@ -0,0 +1,30 @@
+// RUN: %swift -prespecialize-generic-metadata -target %module-target-future -emit-irgen %s | %IRGenFileCheck %s
+
+// REQUIRES: CPU=arm64e
+
+public enum R<X> {
+case a(X)
+case b(Any)
+}
+
+@inline(never)
+func consume<T>(_ t: T) {}
+
+// CHECK:      @"$s4main1ROySiGWV" = {{.*}}%swift.enum_vwtable {
+//           :   ptr @"$s4main1ROwCP.ptrauth.1",
+//           :   ptr @"$s4main1ROwxx.ptrauth.2",
+//           :   ptr @"$s4main1ROwcp.ptrauth.3",
+//           :   ptr @"$s4main1ROwca.ptrauth.4",
+//           :   ptr @"$s4main1ROwtk.ptrauth.5",
+//           :   ptr @"$s4main1ROwta.ptrauth.6",
+// CHECK-SAME:   ptr @swift_getMultiPayloadEnumTagSinglePayload.ptrauth,
+// CHECK-SAME:   ptr @swift_storeMultiPayloadEnumTagSinglePayload.ptrauth,
+//           :   i64 33,
+//           :   i64 40,
+//           :   i32 2293767,
+//           :   i32 254,
+//           :   ptr @"$s4main1ROwug.ptrauth.7",
+//           :   ptr @"$s4main1ROwup.ptrauth.8",
+//           :   ptr @"$s4main1ROwui.ptrauth.9"
+//           : }
+consume(R<Int>.self)
diff --git a/test/IRGen/prespecialized-metadata/struct-inmodule-otherfile-1argument-run.swift b/test/IRGen/prespecialized-metadata/struct-inmodule-otherfile-1argument-run.swift
index 6bac16a11a750..0780ec08e2e4f 100644
--- a/test/IRGen/prespecialized-metadata/struct-inmodule-otherfile-1argument-run.swift
+++ b/test/IRGen/prespecialized-metadata/struct-inmodule-otherfile-1argument-run.swift
@@ -17,8 +17,8 @@ func consume<First>(oneArgument: OneArgument<First>) {
 }
 
 func doit() {
-  // CHECK: [[METADATA_ADDRESS:[0-9a-f]+]] 3 @ 21
+  // CHECK: [[METADATA_ADDRESS:[0-9a-f]+]] 3 @ [[@LINE+1]]
   consume(OneArgument(3))
-  // CHECK: [[METADATA_ADDRESS]] 3 @ 23
+  // CHECK: [[METADATA_ADDRESS]] 3 @ [[@LINE+1]]
   consume(oneArgument: OneArgument(3))
 }
diff --git a/test/IRGen/prespecialized-metadata/struct-outmodule-run.swift b/test/IRGen/prespecialized-metadata/struct-outmodule-run.swift
index b868350040ac6..6979f69012181 100644
--- a/test/IRGen/prespecialized-metadata/struct-outmodule-run.swift
+++ b/test/IRGen/prespecialized-metadata/struct-outmodule-run.swift
@@ -51,27 +51,27 @@ func consumeType_OneArgumentAtFirstUsageDynamic_Dynamic(line: UInt = #line) {
 
 @inline(never)
 func doit() {
-  // CHECK: [[STATIC_METADATA_ADDRESS:[0-9a-f]+]] @ 55
+  // CHECK: [[STATIC_METADATA_ADDRESS:[0-9a-f]+]] @ [[@LINE+1]]
   consumeType_OneArgumentAtFirstUsageStatic_Static()
-  // CHECK: [[STATIC_METADATA_ADDRESS]] @ 57
+  // CHECK: [[STATIC_METADATA_ADDRESS]] @ [[@LINE+1]]
   consumeType_OneArgumentAtFirstUsageStatic_Dynamic()
-  // CHECK: [[STATIC_METADATA_ADDRESS]] @ 59
+  // CHECK: [[STATIC_METADATA_ADDRESS]] @ [[@LINE+1]]
   consumeType_OneArgumentAtFirstUsageStatic_Dynamic()
-  // CHECK: [[DYNAMIC_METADATA_ADDRESS:[0-9a-f]+]] @ 61
+  // CHECK: [[DYNAMIC_METADATA_ADDRESS:[0-9a-f]+]] @ [[@LINE+1]]
   consumeType_OneArgumentAtFirstUsageDynamic_Dynamic()
-  // CHECK: [[DYNAMIC_METADATA_ADDRESS:[0-9a-f]+]] @ 63
+  // CHECK: [[DYNAMIC_METADATA_ADDRESS:[0-9a-f]+]] @ [[@LINE+1]]
   consumeType_OneArgumentAtFirstUsageDynamic_Dynamic()
-  // CHECK: [[DYNAMIC_METADATA_ADDRESS]] @ 65
+  // CHECK: [[DYNAMIC_METADATA_ADDRESS]] @ [[@LINE+1]]
   consumeType_OneArgumentAtFirstUsageDynamic_Static()
 
   let staticMetadata = ptr(to: OneArgument<FirstUsageStatic>.self)
-  // CHECK: [[STATIC_METADATA_ADDRESS]] @ 69
+  // CHECK: [[STATIC_METADATA_ADDRESS]] @ [[@LINE+1]]
   print(staticMetadata, "@", #line)
   assert(isStaticallySpecializedGenericMetadata(staticMetadata))
   assert(!isCanonicalStaticallySpecializedGenericMetadata(staticMetadata))
 
   let dynamicMetadata = ptr(to: OneArgument<FirstUsageDynamic>.self)
-  // CHECK: [[DYNAMIC_METADATA_ADDRESS]] @ 75
+  // CHECK: [[DYNAMIC_METADATA_ADDRESS]] @ [[@LINE+1]]
   print(dynamicMetadata, "@", #line)
   assert(!isStaticallySpecializedGenericMetadata(dynamicMetadata))
   assert(!isCanonicalStaticallySpecializedGenericMetadata(dynamicMetadata))
diff --git a/test/IRGen/profiling_marker_thunks.swift b/test/IRGen/profiling_marker_thunks.swift
index 824fd65be5995..e1a767d9d35d6 100644
--- a/test/IRGen/profiling_marker_thunks.swift
+++ b/test/IRGen/profiling_marker_thunks.swift
@@ -7,7 +7,7 @@
 // RUN: %target-swift-frontend -module-name A -I %t -emit-ir %s | %FileCheck %s --check-prefix=NOTHUNK
 
 // UNSUPPORTED: OS=windows-msvc
-// UNSUPPORTED: OS=linux-gnu, OS=linux-android, OS=linux-androideabi
+// UNSUPPORTED: OS=linux-gnu, OS=linux-android, OS=linux-androideabi, OS=freebsd
 
 // UNSUPPORTED: CPU=arm64e
 
diff --git a/test/IRGen/protocol_accessor_multifile.swift b/test/IRGen/protocol_accessor_multifile.swift
index ee4c41e3ecd32..5e095b1cd0f72 100644
--- a/test/IRGen/protocol_accessor_multifile.swift
+++ b/test/IRGen/protocol_accessor_multifile.swift
@@ -8,7 +8,7 @@
 // CHECK-LABEL: define{{.*}} void @"$s27protocol_accessor_multifile14useExistentialyyF"()
 func useExistential() {
   // CHECK: [[BOX:%.+]] = alloca %T27protocol_accessor_multifile5ProtoP,
-  // CHECK: call swiftcc void @"$s27protocol_accessor_multifile17globalExistentialAA5Proto_pvg"(ptr noalias nocapture sret({{.*}}) [[BOX]])
+  // CHECK: call swiftcc void @"$s27protocol_accessor_multifile17globalExistentialAA5Proto_pvg"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[BOX]])
   // CHECK: call swiftcc void @"$s27protocol_accessor_multifile5ProtoPAAE6methodyyF"
   globalExistential.method()
   // CHECK: call void @__swift_destroy_boxed_opaque_existential_1(ptr [[BOX]])
diff --git a/test/IRGen/protocol_resilience.sil b/test/IRGen/protocol_resilience.sil
index 7d2c1784e7401..5a1feecbd704d 100644
--- a/test/IRGen/protocol_resilience.sil
+++ b/test/IRGen/protocol_resilience.sil
@@ -173,7 +173,7 @@ bb0(%0 : $*Self):
   // implementation
 
   // CHECK-NEXT: [[CONTEXT:%.*]] = call noalias ptr @swift_allocObject({{.*}})
-  // CHECK:      [[WTABLE_ADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr [[CONTEXT]], i32 0, i32 2
+  // CHECK:      [[WTABLE_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr [[CONTEXT]], i32 0, i32 2
   // CHECK-NEXT: store ptr %SelfWitnessTable, ptr [[WTABLE_ADDR]]
 
   %fn3 = function_ref @defaultC : $@convention(witness_method: ResilientProtocol) <Self where Self : ResilientProtocol> (@in_guaranteed Self) -> ()
@@ -211,7 +211,7 @@ bb0(%0 : $@thick Self.Type):
   // implementation
 
   // CHECK-NEXT: [[CONTEXT:%.*]] = call noalias ptr @swift_allocObject({{.*}})
-  // CHECK:      [[WTABLE_ADDR:%.*]] = getelementptr inbounds <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr [[CONTEXT]], i32 0, i32 2
+  // CHECK:      [[WTABLE_ADDR:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, [{{4|8}} x i8], ptr }>, ptr [[CONTEXT]], i32 0, i32 2
   // CHECK-NEXT: store ptr %SelfWitnessTable, ptr [[WTABLE_ADDR]]
 
   %fn3 = function_ref @defaultF : $@convention(witness_method: ResilientProtocol) <Self where Self : ResilientProtocol> (@thick Self.Type) -> ()
@@ -262,7 +262,7 @@ struct ConformingStruct : ResilientProtocol {
   static func defaultF()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @noDefaultA(ptr noalias nocapture swiftself %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @noDefaultA(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 
 sil @noDefaultA : $@convention(witness_method: ResilientProtocol) (@in_guaranteed ConformingStruct) -> () {
@@ -281,7 +281,7 @@ bb0(%0 : $*ConformingStruct):
 }
 
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @noDefaultB(ptr noalias nocapture swiftself %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @noDefaultB(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 
 sil @noDefaultB : $@convention(witness_method: ResilientProtocol) (@in_guaranteed ConformingStruct) -> () {
@@ -289,7 +289,7 @@ bb0(%0 : $*ConformingStruct):
 
   // Make sure we can partially apply direct references to default implementations
   // CHECK-NEXT: [[CONTEXT:%.*]] = call noalias ptr @swift_allocObject({{.*}})
-  // CHECK-NEXT: [[WTABLE:%.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr [[CONTEXT]], i32 0, i32 1
+  // CHECK-NEXT: [[WTABLE:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr [[CONTEXT]], i32 0, i32 1
   // CHECK-NEXT: store ptr %SelfWitnessTable, ptr [[WTABLE]]
 
   %fn1 = function_ref @defaultC : $@convention(witness_method: ResilientProtocol) <Self where Self : ResilientProtocol> (@in_guaranteed Self) -> ()
@@ -324,7 +324,7 @@ bb0(%0 : $*T):
   return %result : $()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @passConformingType(ptr noalias nocapture %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @passConformingType(ptr noalias {{(nocapture|captures\(none\))}} %0)
 sil @passConformingType : $@convention(thin) (@in ResilientConformingType) -> () {
 bb0(%0 : $*ResilientConformingType):
 
@@ -381,7 +381,7 @@ bb0(%0 : $*T):
   return %result : $()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @passConformingTypeRefined(ptr noalias nocapture %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @passConformingTypeRefined(ptr noalias {{(nocapture|captures\(none\))}} %0)
 sil @passConformingTypeRefined : $@convention(thin) (@in AnotherConformingStruct) -> () {
 bb0(%0 : $*AnotherConformingStruct):
 
@@ -424,7 +424,7 @@ bb0(%0 : $*T):
   return %result : $()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @passConformingTypeAssoc(ptr noalias nocapture %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @passConformingTypeAssoc(ptr noalias {{(nocapture|captures\(none\))}} %0)
 sil @passConformingTypeAssoc : $@convention(thin) (@in ConformsWithResilientAssoc) -> () {
 bb0(%0 : $*ConformsWithResilientAssoc):
 
diff --git a/test/IRGen/protocol_resilience_thunks.swift b/test/IRGen/protocol_resilience_thunks.swift
index 7317d671b3690..b28b63a6bf648 100644
--- a/test/IRGen/protocol_resilience_thunks.swift
+++ b/test/IRGen/protocol_resilience_thunks.swift
@@ -52,20 +52,20 @@ public protocol MyResilientProtocol {
 // CHECK-NEXT: [[RESULT:%.*]] = call swiftcc i1 [[WITNESS]](ptr noalias swiftself %0, ptr %1, ptr %2)
 // CHECK-NEXT: ret i1 [[RESULT]]
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s26protocol_resilience_thunks19MyResilientProtocolP10returnsAnyypyFTj"(ptr noalias nocapture sret({{.*}}) %0, ptr noalias swiftself %1, ptr %2, ptr %3)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s26protocol_resilience_thunks19MyResilientProtocolP10returnsAnyypyFTj"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias swiftself %1, ptr %2, ptr %3)
 // CHECK:      [[WITNESS_ADDR:%.*]] = getelementptr inbounds ptr, ptr %3, i32 3
 // CHECK-NEXT: [[WITNESS:%.*]] = load ptr, ptr [[WITNESS_ADDR]]
 // CHECK-arm64e-NEXT: ptrtoint ptr [[WITNESS_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
-// CHECK-NEXT: call swiftcc void [[WITNESS]](ptr noalias nocapture sret({{.*}}) %0, ptr noalias swiftself %1, ptr %2, ptr %3)
+// CHECK-NEXT: call swiftcc void [[WITNESS]](ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias swiftself %1, ptr %2, ptr %3)
 // CHECK-NEXT: ret void
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s26protocol_resilience_thunks19MyResilientProtocolP12throwingFuncyyKFTj"(ptr noalias swiftself %0, ptr{{( noalias nocapture( swifterror)? dereferenceable\(.\))?}} %1, ptr %2, ptr %3)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s26protocol_resilience_thunks19MyResilientProtocolP12throwingFuncyyKFTj"(ptr noalias swiftself %0, ptr{{( noalias( nocapture)?( swifterror)?( captures\(none\))? dereferenceable\(.\))?}} %1, ptr %2, ptr %3)
 // CHECK:      [[WITNESS_ADDR:%.*]] = getelementptr inbounds ptr, ptr %3, i32 4
 // CHECK-NEXT: [[WITNESS:%.*]] = load ptr, ptr [[WITNESS_ADDR]]
 // CHECK-arm64e-NEXT: ptrtoint ptr [[WITNESS_ADDR]] to i64
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
-// CHECK-NEXT: call swiftcc void [[WITNESS]](ptr noalias swiftself %0, ptr{{( noalias nocapture( swifterror)? dereferenceable\(.\))?}} %1, ptr %2, ptr %3)
+// CHECK-NEXT: call swiftcc void [[WITNESS]](ptr noalias swiftself %0, ptr{{( noalias( nocapture)?( swifterror)?( captures\(none\))? dereferenceable\(.\))?}} %1, ptr %2, ptr %3)
 // CHECK-NEXT: ret void
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s26protocol_resilience_thunks19MyResilientProtocolP11genericFuncyqd__qd__lFTj"(ptr noalias sret({{.*}}) %0, ptr noalias %1, ptr %2, ptr noalias swiftself %3, ptr %4, ptr %5)
diff --git a/test/IRGen/ptrauth-protocols.sil b/test/IRGen/ptrauth-protocols.sil
index dde6c45add282..99ff92d581b5d 100644
--- a/test/IRGen/ptrauth-protocols.sil
+++ b/test/IRGen/ptrauth-protocols.sil
@@ -75,7 +75,7 @@ bb0:
 //   Fetch T.Assoc : P.
 // CHECK-NEXT:    %T.Assoc.P = call swiftcc ptr @swift_getAssociatedConformanceWitness(ptr %T.Q, ptr %T, ptr [[T_ASSOC]]
 //   Fetch T.Assoc.foo
-// CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds ptr, ptr %T.Assoc.P, i32 1
+// CHECK:         [[T0:%.*]] = getelementptr inbounds ptr, ptr %T.Assoc.P, i32 1
 // CHECK-NEXT:    [[T1:%.*]] = load ptr, ptr [[T0]], align 8
 // CHECK-NEXT:    [[T2:%.*]] = ptrtoint ptr [[T0]] to i64
 // CHECK-NEXT:    [[DISC:%.*]] = call i64 @llvm.ptrauth.blend(i64 [[T2]], i64 53700)
diff --git a/test/IRGen/raw_layout.swift b/test/IRGen/raw_layout.swift
index 2c0200be2182a..7f582ae627c22 100644
--- a/test/IRGen/raw_layout.swift
+++ b/test/IRGen/raw_layout.swift
@@ -13,8 +13,8 @@ import RawLayoutCXX
 // CHECK-SAME:  , {{i64|i32}} 4
 // stride
 // CHECK-SAME:  , {{i64|i32}} 4
-// flags: alignment 3, noncopyable, non-bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800003>
+// flags: alignment 3, noncopyable, non-bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x3800003>
 
 @_rawLayout(size: 4, alignment: 4)
 struct Lock: ~Copyable { }
@@ -29,8 +29,8 @@ struct PaddedStride {
 // CHECK-SAME:  , {{i64|i32}} 5
 // stride
 // CHECK-SAME:  , {{i64|i32}} 8
-// flags: alignment 3, noncopyable, non-bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800003>
+// flags: alignment 3, noncopyable, non-bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x3800003>
 @_rawLayout(like: PaddedStride)
 struct LikePaddedStride: ~Copyable {}
 
@@ -39,8 +39,8 @@ struct LikePaddedStride: ~Copyable {}
 // CHECK-SAME:  , {{i64|i32}} 8
 // stride
 // CHECK-SAME:  , {{i64|i32}} 8
-// flags: alignment 3, noncopyable, non-bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800003>
+// flags: alignment 3, noncopyable, non-bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x3800003>
 @_rawLayout(likeArrayOf: PaddedStride, count: 1)
 struct LikePaddedStrideArray1: ~Copyable {}
 
@@ -49,9 +49,9 @@ struct LikePaddedStrideArray1: ~Copyable {}
 // CHECK-SAME:  , {{i64|i32}} 16
 // stride
 // CHECK-SAME:  , {{i64|i32}} 16
-// flags: alignment 3, noncopyable, non-bitwise-borrowable, (on 32-bit platforms) not storable inline
-// CHECK-64-SAME:  , <i32 0x1800003>
-// CHECK-32-SAME:  , <i32 0x1820003>
+// flags: alignment 3, noncopyable, non-bitwise-borrowable, addressable for dependencies (on 32-bit platforms) not storable inline
+// CHECK-64-SAME:  , <i32 0x3800003>
+// CHECK-32-SAME:  , <i32 0x3820003>
 @_rawLayout(likeArrayOf: PaddedStride, count: 2)
 struct LikePaddedStrideArray2: ~Copyable {}
 
@@ -60,8 +60,8 @@ struct LikePaddedStrideArray2: ~Copyable {}
 // CHECK-SAME:  , {{i64|i32}} 12
 // stride
 // CHECK-SAME:  , {{i64|i32}} 12
-// flags: alignment 3, noncopyable, non-bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800003>
+// flags: alignment 3, noncopyable, non-bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x3800003>
 struct Keymaster: ~Copyable {
     let lock1: Lock
     let lock2: Lock
@@ -127,8 +127,8 @@ struct Vector<T, let N: Int>: ~Copyable {}
 // CHECK-SAME:  , {{i64|i32}} 8
 // stride
 // CHECK-SAME:  , {{i64|i32}} 8
-// flags: alignment 3, noncopyable, non-bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800003>
+// flags: alignment 3, noncopyable, non-bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x3800003>
 struct UsesCell: ~Copyable {
     let someCondition: Bool
     let specialInt: Cell<Int32>
@@ -139,8 +139,8 @@ struct UsesCell: ~Copyable {
 // CHECK-SAME:  , {{i64|i32}} 3
 // stride
 // CHECK-SAME:  , {{i64|i32}} 3
-// flags: alignment 0, noncopyable, non-bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800000>
+// flags: alignment 0, noncopyable, non-bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x3800000>
 struct BufferOf3Bool: ~Copyable {
     let buffer: SmallVectorOf3<Bool>
 }
@@ -150,8 +150,8 @@ struct BufferOf3Bool: ~Copyable {
 // CHECK-SAME:  , {{i64|i32}} 48
 // stride
 // CHECK-SAME:  , {{i64|i32}} 48
-// flags: alignment 7, noncopyable, non-bitwise-borrowable, is not inline
-// CHECK-SAME:  , <i32 0x1820007>
+// flags: alignment 7, noncopyable, non-bitwise-borrowable, addressable for dependencies, is not inline
+// CHECK-SAME:  , <i32 0x3820007>
 struct BadBuffer: ~Copyable {
     let buffer: SmallVectorOf3<Int64?>
 }
@@ -161,8 +161,8 @@ struct BadBuffer: ~Copyable {
 // CHECK-SAME:  , {{i64|i32}} 2
 // stride
 // CHECK-SAME:  , {{i64|i32}} 2
-// flags: alignment 0, noncopyable, non-bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800000>
+// flags: alignment 0, noncopyable, non-bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x3800000>
 struct UsesVector: ~Copyable {
     let buffer: Vector<UInt8, 2>
 }
@@ -172,8 +172,8 @@ struct UsesVector: ~Copyable {
 // CHECK-SAME:  , {{i64|i32}} 48
 // stride
 // CHECK-SAME:  , {{i64|i32}} 48
-// flags: alignment 7, noncopyable, non-bitwise-borrowable, is not inline
-// CHECK-SAME:  , <i32 0x1820007>
+// flags: alignment 7, noncopyable, non-bitwise-borrowable, addressable for dependencies, is not inline
+// CHECK-SAME:  , <i32 0x3820007>
 struct BadBuffer2: ~Copyable {
     let buffer: Vector<Int64?, 3>
 }
@@ -207,8 +207,8 @@ struct CellThatMovesAsLike<T>: ~Copyable {}
 // CHECK-SAME:  , {{i64|i32}} 1
 // stride
 // CHECK-SAME:  , {{i64|i32}} 1
-// flags: not copyable, not bitwise takable, not pod, not inline
-// CHECK-SAME:  , <i32 0x930000>
+// flags: not copyable, not bitwise takable, not pod, not inline, addressable for dependencies
+// CHECK-SAME:  , <i32 0x2930000>
 struct ConcreteMoveAsLike: ~Copyable {
   let cell: CellThatMovesAsLike<NonBitwiseTakableCXXType>
 }
@@ -224,8 +224,8 @@ struct ConcreteMoveAsLike: ~Copyable {
 // CHECK-SAME:  , {{i64|i32}} 4
 // stride
 // CHECK-SAME:  , {{i64|i32}} 4
-// flags: alignment 3, not copyable, not bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800003>
+// flags: alignment 3, not copyable, not bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x3800003>
 struct ConcreteIntMoveAsLike: ~Copyable {
   let cell: CellThatMovesAsLike<Int32>
 }
@@ -257,8 +257,8 @@ struct SmallVectorOf2MovesAsLike<T: ~Copyable>: ~Copyable {}
 // CHECK-SAME:  , {{i64|i32}} 2
 // stride
 // CHECK-SAME:  , {{i64|i32}} 2
-// flags: not copyable, not bitwise takable, not pod, not inline
-// CHECK-SAME:  , <i32 0x930000>
+// flags: not copyable, not bitwise takable, not pod, not inline, addressable for dependencies
+// CHECK-SAME:  , <i32 0x2930000>
 struct ConcreteSmallVectorMovesAsLike: ~Copyable {
   let vector: SmallVectorOf2MovesAsLike<NonBitwiseTakableCXXType>
 }
@@ -274,8 +274,8 @@ struct ConcreteSmallVectorMovesAsLike: ~Copyable {
 // CHECK-SAME:  , {{i64|i32}} 8
 // stride
 // CHECK-SAME:  , {{i64|i32}} 8
-// flags: alignment 3, not copyable, not bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800003>
+// flags: alignment 3, not copyable, not bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x3800003>
 struct ConcreteSmallVectorIntMovesAsLike: ~Copyable {
   let vector: SmallVectorOf2MovesAsLike<Int32>
 }
@@ -307,8 +307,8 @@ struct VectorMovesAsLike<T: ~Copyable, let N: Int>: ~Copyable {}
 // CHECK-SAME:  , {{i64|i32}} 4
 // stride
 // CHECK-SAME:  , {{i64|i32}} 4
-// flags: not copyable, not bitwise takable, not pod, not inline
-// CHECK-SAME:  , <i32 0x930000>
+// flags: not copyable, not bitwise takable, not pod, not inline, addressable for dependencies
+// CHECK-SAME:  , <i32 0x2930000>
 struct ConcreteVectorMovesAsLike: ~Copyable {
   let vector: VectorMovesAsLike<NonBitwiseTakableCXXType, 4>
 }
@@ -324,9 +324,9 @@ struct ConcreteVectorMovesAsLike: ~Copyable {
 // CHECK-SAME:  , {{i64|i32}} 16
 // stride
 // CHECK-SAME:  , {{i64|i32}} 16
-// flags: alignment 3, not copyable, not bitwise-borrowable, (on 32-bit platforms) not storable inline
-// CHECK-64-SAME:  , <i32 0x1800003>
-// CHECK-32-SAME:  , <i32 0x1820003>
+// flags: alignment 3, not copyable, not bitwise-borrowable, addressable for dependencies, (on 32-bit platforms) not storable inline
+// CHECK-64-SAME:  , <i32 0x3800003>
+// CHECK-32-SAME:  , <i32 0x3820003>
 struct ConcreteVectorIntMovesAsLike: ~Copyable {
   let vector: VectorMovesAsLike<Int32, 4>
 }
@@ -348,7 +348,7 @@ entry(%K: $*Keymaster):
     return undef : $()
 }
 
-// CHECK: define {{.*}}swiftcc ptr @get_cell_addr(ptr %"Cell<T>", ptr {{.*}} swiftself [[SELF:%.*]])
+// CHECK: define {{.*}}swiftcc ptr @get_cell_addr(ptr %"Cell<T>", ptr {{.*}} swiftself{{.*}} [[SELF:%.*]])
 // CHECK-NEXT:   entry:
 // CHECK-NEXT:     ret ptr [[SELF]]
 sil @get_cell_addr : $@convention(method) <T> (@in_guaranteed Cell<T>) -> UnsafeMutablePointer<T> {
@@ -430,7 +430,7 @@ entry(%0 : $*Cell<T>):
 //===----------------------------------------------------------------------===//
 
 // CHECK-LABEL: define {{.*}} void @"$s10raw_layout18ConcreteMoveAsLikeVwxx"(ptr {{.*}} %object, ptr %ConcreteMoveAsLike)
-// CHECK:         [[OBJ_CELL:%.*]] = getelementptr inbounds %T10raw_layout18ConcreteMoveAsLikeV, ptr %object, i32 0, i32 0
+// CHECK:         [[OBJ_CELL:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout18ConcreteMoveAsLikeV, ptr %object, i32 0, i32 0
 // CHECK:         {{invoke void|invoke ptr|call void|call ptr}} @{{.*}}(ptr [[OBJ_CELL]])
 
 //===----------------------------------------------------------------------===//
@@ -438,8 +438,8 @@ entry(%0 : $*Cell<T>):
 //===----------------------------------------------------------------------===//
 
 // CHECK-LABEL: define {{.*}} ptr @"$s10raw_layout18ConcreteMoveAsLikeVwtk"(ptr {{.*}} %dest, ptr {{.*}} %src, ptr %ConcreteMoveAsLike)
-// CHECK:         [[DEST_CELL:%.*]] = getelementptr inbounds %T10raw_layout18ConcreteMoveAsLikeV, ptr %dest, i32 0, i32 0
-// CHECK:         [[SRC_CELL:%.*]] = getelementptr inbounds %T10raw_layout18ConcreteMoveAsLikeV, ptr %src, i32 0, i32 0
+// CHECK:         [[DEST_CELL:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout18ConcreteMoveAsLikeV, ptr %dest, i32 0, i32 0
+// CHECK:         [[SRC_CELL:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout18ConcreteMoveAsLikeV, ptr %src, i32 0, i32 0
 // CHECK:         {{invoke void|invoke ptr|call ptr}} @{{.*}}(ptr [[DEST_CELL]], ptr [[SRC_CELL]])
 
 //===----------------------------------------------------------------------===//
@@ -447,8 +447,8 @@ entry(%0 : $*Cell<T>):
 //===----------------------------------------------------------------------===//
 
 // CHECK-LABEL: define {{.*}} ptr @"$s10raw_layout18ConcreteMoveAsLikeVwta"(ptr {{.*}} %dest, ptr {{.*}} %src, ptr %ConcreteMoveAsLike)
-// CHECK:         [[DEST_CELL:%.*]] = getelementptr inbounds %T10raw_layout18ConcreteMoveAsLikeV, ptr %dest, i32 0, i32 0
-// CHECK:         [[SRC_CELL:%.*]] = getelementptr inbounds %T10raw_layout18ConcreteMoveAsLikeV, ptr %src, i32 0, i32 0
+// CHECK:         [[DEST_CELL:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout18ConcreteMoveAsLikeV, ptr %dest, i32 0, i32 0
+// CHECK:         [[SRC_CELL:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout18ConcreteMoveAsLikeV, ptr %src, i32 0, i32 0
 // CHECK:         {{invoke void|invoke ptr|call ptr}} @{{.*}}(ptr [[DEST_CELL]], ptr [[SRC_CELL]])
 
 //===----------------------------------------------------------------------===//
@@ -469,7 +469,7 @@ entry(%0 : $*Cell<T>):
 // CHECK:         store {{i64|i32}} [[NEW_I]], ptr [[I_ALLOCA]]
 // CHECK:         [[T_ADDR:%.*]] = getelementptr inbounds ptr, ptr %"SmallVectorOf2MovesAsLike<T>", {{i64|i32}} 2
 // CHECK-NEXT:    [[T:%.*]] = load ptr, ptr [[T_ADDR]]
-// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
+// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
 // CHECK-NEXT:    [[STRIDE:%.*]] = load {{i64|i32}}, ptr [[STRIDE_GEP]]
 // CHECK:         [[OFFSET:%.*]] = mul {{i64|i32}} [[I]], [[STRIDE]]
 // CHECK-NEXT:    [[OBJ_ELT:%.*]] = getelementptr inbounds i8, ptr %object, {{i64|i32}} [[OFFSET]]
@@ -498,7 +498,7 @@ entry(%0 : $*Cell<T>):
 // CHECK:         store {{i64|i32}} [[NEW_I]], ptr [[I_ALLOCA]]
 // CHECK:         [[T_ADDR:%.*]] = getelementptr inbounds ptr, ptr %"SmallVectorOf2MovesAsLike<T>", {{i64|i32}} 2
 // CHECK-NEXT:    [[T:%.*]] = load ptr, ptr [[T_ADDR]]
-// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
+// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
 // CHECK-NEXT:    [[STRIDE:%.*]] = load {{i64|i32}}, ptr [[STRIDE_GEP]]
 // CHECK:         [[OFFSET_0:%.*]] = mul {{i64|i32}} [[I]], [[STRIDE]]
 // CHECK-NEXT:    [[SRC_ELT_0:%.*]] = getelementptr inbounds i8, ptr %src, {{i64|i32}} [[OFFSET_0]]
@@ -528,7 +528,7 @@ entry(%0 : $*Cell<T>):
 // CHECK:         store {{i64|i32}} [[NEW_I]], ptr [[I_ALLOCA]]
 // CHECK:         [[T_ADDR:%.*]] = getelementptr inbounds ptr, ptr %"SmallVectorOf2MovesAsLike<T>", {{i64|i32}} 2
 // CHECK-NEXT:    [[T:%.*]] = load ptr, ptr [[T_ADDR]]
-// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
+// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
 // CHECK-NEXT:    [[STRIDE:%.*]] = load {{i64|i32}}, ptr [[STRIDE_GEP]]
 // CHECK:         [[OFFSET_0:%.*]] = mul {{i64|i32}} [[I]], [[STRIDE]]
 // CHECK-NEXT:    [[SRC_ELT_0:%.*]] = getelementptr inbounds i8, ptr %src, {{i64|i32}} [[OFFSET_0]]
@@ -546,7 +546,7 @@ entry(%0 : $*Cell<T>):
 
 // CHECK-LABEL: define {{.*}} void @"$s10raw_layout30ConcreteSmallVectorMovesAsLikeVwxx"(ptr {{.*}} %object, ptr %ConcreteSmallVectorMovesAsLike)
 // CHECK:         [[I_ALLOCA:%.*]] = alloca {{i64|i32}}
-// CHECK:         [[OBJ_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %object, i32 0, i32 0
+// CHECK:         [[OBJ_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %object, i32 0, i32 0
 // CHECK:         store {{i64|i32}} 0, ptr [[I_ALLOCA]]
 // CHECK:         br label %[[COND_BR:.*]]
 
@@ -573,8 +573,8 @@ entry(%0 : $*Cell<T>):
 
 // CHECK-LABEL: define {{.*}} ptr @"$s10raw_layout30ConcreteSmallVectorMovesAsLikeVwtk"(ptr {{.*}} %dest, ptr {{.*}} %src, ptr %ConcreteSmallVectorMovesAsLike)
 // CHECK:         [[I_ALLOCA:%.*]] = alloca {{i64|i32}}
-// CHECK:         [[DEST_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %dest, i32 0, i32 0
-// CHECK:         [[SRC_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %src, i32 0, i32 0
+// CHECK:         [[DEST_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %dest, i32 0, i32 0
+// CHECK:         [[SRC_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %src, i32 0, i32 0
 // CHECK:         store {{i64|i32}} 0, ptr [[I_ALLOCA]]
 // CHECK:         br label %[[COND_BR:.*]]
 
@@ -602,8 +602,8 @@ entry(%0 : $*Cell<T>):
 
 // CHECK-LABEL: define {{.*}} ptr @"$s10raw_layout30ConcreteSmallVectorMovesAsLikeVwta"(ptr {{.*}} %dest, ptr {{.*}} %src, ptr %ConcreteSmallVectorMovesAsLike)
 // CHECK:         [[I_ALLOCA:%.*]] = alloca {{i64|i32}}
-// CHECK:         [[DEST_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %dest, i32 0, i32 0
-// CHECK:         [[SRC_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %src, i32 0, i32 0
+// CHECK:         [[DEST_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %dest, i32 0, i32 0
+// CHECK:         [[SRC_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout30ConcreteSmallVectorMovesAsLikeV, ptr %src, i32 0, i32 0
 // CHECK:         store {{i64|i32}} 0, ptr [[I_ALLOCA]]
 // CHECK:         br label %[[COND_BR:.*]]
 
@@ -655,7 +655,7 @@ entry(%0 : $*Cell<T>):
 // CHECK:         store {{i64|i32}} [[NEW_I]], ptr [[I_ALLOCA]]
 // CHECK:         [[T_ADDR:%.*]] = getelementptr inbounds ptr, ptr %"VectorMovesAsLike<T, N>", {{i64|i32}} 2
 // CHECK-NEXT:    [[T:%.*]] = load ptr, ptr [[T_ADDR]]
-// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
+// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
 // CHECK-NEXT:    [[STRIDE:%.*]] = load {{i64|i32}}, ptr [[STRIDE_GEP]]
 // CHECK:         [[OFFSET:%.*]] = mul {{i64|i32}} [[I]], [[STRIDE]]
 // CHECK-NEXT:    [[OBJECT:%.*]] = getelementptr inbounds i8, ptr %object, {{i64|i32}} [[OFFSET]]
@@ -687,7 +687,7 @@ entry(%0 : $*Cell<T>):
 // CHECK:         store {{i64|i32}} [[NEW_I]], ptr [[I_ALLOCA]]
 // CHECK:         [[T_ADDR:%.*]] = getelementptr inbounds ptr, ptr %"VectorMovesAsLike<T, N>", {{i64|i32}} 2
 // CHECK-NEXT:    [[T:%.*]] = load ptr, ptr [[T_ADDR]]
-// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
+// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
 // CHECK-NEXT:    [[STRIDE:%.*]] = load {{i64|i32}}, ptr [[STRIDE_GEP]]
 // CHECK:         [[OFFSET_0:%.*]] = mul {{i64|i32}} [[I]], [[STRIDE]]
 // CHECK-NEXT:    [[SRC_ELT_0:%.*]] = getelementptr inbounds i8, ptr %src, {{i64|i32}} [[OFFSET_0]]
@@ -720,7 +720,7 @@ entry(%0 : $*Cell<T>):
 // CHECK:         store {{i64|i32}} [[NEW_I]], ptr [[I_ALLOCA]]
 // CHECK:         [[T_ADDR:%.*]] = getelementptr inbounds ptr, ptr %"VectorMovesAsLike<T, N>", {{i64|i32}} 2
 // CHECK-NEXT:    [[T:%.*]] = load ptr, ptr [[T_ADDR]]
-// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
+// CHECK:         [[STRIDE_GEP:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr {{%.*}}, i32 0, i32 9
 // CHECK-NEXT:    [[STRIDE:%.*]] = load {{i64|i32}}, ptr [[STRIDE_GEP]]
 // CHECK:         [[OFFSET_0:%.*]] = mul {{i64|i32}} [[I]], [[STRIDE]]
 // CHECK-NEXT:    [[SRC_ELT_0:%.*]] = getelementptr inbounds i8, ptr %src, {{i64|i32}} [[OFFSET_0]]
@@ -738,7 +738,7 @@ entry(%0 : $*Cell<T>):
 
 // CHECK-LABEL: define {{.*}} void @"$s10raw_layout25ConcreteVectorMovesAsLikeVwxx"(ptr {{.*}} %object, ptr %ConcreteVectorMovesAsLike)
 // CHECK:         [[I_ALLOCA:%.*]] = alloca {{i64|i32}}
-// CHECK:         [[OBJ_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %object, i32 0, i32 0
+// CHECK:         [[OBJ_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %object, i32 0, i32 0
 // CHECK:         store {{i64|i32}} 0, ptr [[I_ALLOCA]]
 // CHECK:         br label %[[COND_BR:.*]]
 
@@ -765,8 +765,8 @@ entry(%0 : $*Cell<T>):
 
 // CHECK-LABEL: define {{.*}} ptr @"$s10raw_layout25ConcreteVectorMovesAsLikeVwtk"(ptr {{.*}} %dest, ptr {{.*}} %src, ptr %ConcreteVectorMovesAsLike)
 // CHECK:         [[I_ALLOCA:%.*]] = alloca {{i64|i32}}
-// CHECK:         [[DEST_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %dest, i32 0, i32 0
-// CHECK:         [[SRC_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %src, i32 0, i32 0
+// CHECK:         [[DEST_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %dest, i32 0, i32 0
+// CHECK:         [[SRC_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %src, i32 0, i32 0
 // CHECK:         store {{i64|i32}} 0, ptr [[I_ALLOCA]]
 // CHECK:         br label %[[COND_BR:.*]]
 
@@ -794,8 +794,8 @@ entry(%0 : $*Cell<T>):
 
 // CHECK-LABEL: define {{.*}} ptr @"$s10raw_layout25ConcreteVectorMovesAsLikeVwta"(ptr {{.*}} %dest, ptr {{.*}} %src, ptr %ConcreteVectorMovesAsLike)
 // CHECK:         [[I_ALLOCA:%.*]] = alloca {{i64|i32}}
-// CHECK:         [[DEST_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %dest, i32 0, i32 0
-// CHECK:         [[SRC_VECTOR:%.*]] = getelementptr inbounds %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %src, i32 0, i32 0
+// CHECK:         [[DEST_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %dest, i32 0, i32 0
+// CHECK:         [[SRC_VECTOR:%.*]] = getelementptr inbounds{{.*}} %T10raw_layout25ConcreteVectorMovesAsLikeV, ptr %src, i32 0, i32 0
 // CHECK:         store {{i64|i32}} 0, ptr [[I_ALLOCA]]
 // CHECK:         br label %[[COND_BR:.*]]
 
diff --git a/test/IRGen/raw_layout_multifile.swift b/test/IRGen/raw_layout_multifile.swift
index bb0422ee50061..0b6d31df8513d 100644
--- a/test/IRGen/raw_layout_multifile.swift
+++ b/test/IRGen/raw_layout_multifile.swift
@@ -13,8 +13,8 @@ public struct Foo<T>: ~Copyable {}
 // CHECK-SAME:  , {{i64|i32}} 4
 // stride
 // CHECK-SAME:  , {{i64|i32}} 4
-// flags: alignment 3, noncopyable, non-bitwise-borrowable
-// CHECK-SAME:  , <i32 0x1800003>
+// flags: alignment 3, noncopyable, non-bitwise-borrowable, addressable for dependencies
+// CHECK-SAME:  , <i32 0x380_0003>
 struct MyInt: ~Copyable {
   let x: Int32Fake
 }
@@ -24,8 +24,8 @@ struct MyInt: ~Copyable {
 // CHECK-SAME:  , {{i64|i32}} 48
 // stride
 // CHECK-SAME:  , {{i64|i32}} 48
-// flags: alignment 7, noncopyable, non-bitwise-borrowable, is not inline
-// CHECK-SAME:  , <i32 0x1820007>
+// flags: alignment 7, noncopyable, non-bitwise-borrowable, addressable for dependencies, is not inline
+// CHECK-SAME:  , <i32 0x382_0007>
 struct BadBuffer: ~Copyable {
   let buf = SmallVectorOf3<Int64?>()
 }
@@ -35,10 +35,10 @@ struct BadBuffer: ~Copyable {
 // CHECK-SAME:  , {{i64|i32}} 8
 // stride
 // CHECK-SAME:  , {{i64|i32}} 8
-// flags-32: alignment 7, noncopyable, non-bitwise-borrowable, is not inline
-// CHECK-SAME-32:  , <i32 0x1820007>
-// flags-64: alignment 7, noncopyable, non-bitwise-borrowable
-// CHECK-SAME-64:  , <i32 0x1800007>
+// flags-32: alignment 7, noncopyable, non-bitwise-borrowable, addressable for dependencies, is not inline
+// CHECK-32-SAME:  , <i32 0x3820007>
+// flags-64: alignment 7, noncopyable, non-bitwise-borrowable, addressable for dependencies
+// CHECK-64-SAME:  , <i32 0x3800007>
 struct Weird: ~Copyable {
   let value = UnsafeCell<Int64>()
 }
diff --git a/test/IRGen/relative_protocol_witness_table.swift b/test/IRGen/relative_protocol_witness_table.swift
index 8c6c24627f959..27b3fc0b3a78f 100644
--- a/test/IRGen/relative_protocol_witness_table.swift
+++ b/test/IRGen/relative_protocol_witness_table.swift
@@ -319,7 +319,7 @@ func instantiate_conditional_conformance_2nd<T>(_ t : T)  where T: Sub, T.S == T
 
 // CHECK: define{{.*}} swiftcc void @"$s1A39instantiate_conditional_conformance_2ndyyxAA3SubRz1SQzRszlF"(ptr {{.*}}, ptr [[T:%.*]], ptr [[TSUB:%.*]])
 // CHECK:  [[CONDBUFFER:%.*]] = alloca [1 x ptr]
-// CHECK:  [[T0:%.*]] = getelementptr inbounds [1 x ptr], ptr [[CONDBUFFER]], i32 0, i32 0
+// CHECK:  [[T0:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[CONDBUFFER]], i32 0, i32 0
 // CHECK:  [[T1:%.*]] = getelementptr inbounds ptr, ptr [[T0]], i32 0
 // CHECK:  store ptr [[TSUB]], ptr [[T1]]
 // CHECK:  call ptr @swift_getWitnessTableRelative({{.*}}@"$s1A1XVyxGAA3SubA2aERz1SQzRszlMc{{.*}}, ptr {{.*}}, ptr [[T0]])
@@ -331,7 +331,7 @@ func instantiate_conditional_conformance_2nd<T>(_ t : T)  where T: Sub, T.S == T
 // CHECK:   [[T3:%.*]] = getelementptr inbounds ptr, ptr [[C1]], i32 0
 // CHECK:   [[T4:%.*]] = load ptr, ptr [[T3]]
 // CHECK:   [[TBASE:%.*]] = call ptr @__swift_relative_protocol_witness_table_parent_1(ptr [[T4]])
-// CHECK:   [[T24:%.*]] = getelementptr inbounds [1 x ptr], ptr [[C2]], i32 0, i32 0
+// CHECK:   [[T24:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[C2]], i32 0, i32 0
 // CHECK:   [[T25:%.*]] = getelementptr inbounds ptr, ptr [[T24]], i32 0
 // CHECK:   store ptr [[TBASE]], ptr [[T25]]
 // CHECK:   [[T26:%.*]] = call ptr @swift_getWitnessTableRelative({{.*}}@"$s1A1XVyxGAA4BaseA2aERzlMc{{.*}}, ptr {{.*}}, ptr [[T24]])
diff --git a/test/IRGen/run-coroutine_accessors.swift b/test/IRGen/run-coroutine_accessors.swift
index 3308f6f716cc0..fbf23d5d4fc8e 100644
--- a/test/IRGen/run-coroutine_accessors.swift
+++ b/test/IRGen/run-coroutine_accessors.swift
@@ -4,7 +4,6 @@
 // RUN: %target-swift-frontend                              \
 // RUN:     %t/Library.swift                                \
 // RUN:     -emit-module                                    \
-// RUN:     -target %target-future-triple                   \
 // RUN:     -enable-library-evolution                       \
 // RUN:     -module-name Library                            \
 // RUN:     -enable-experimental-feature CoroutineAccessors \
@@ -13,7 +12,6 @@
 // RUN: %target-build-swift                                 \
 // RUN:     %t/Downstream.swift                             \
 // RUN:     -c                                              \
-// RUN:     -target %target-future-triple                   \
 // RUN:     -Onone                                          \
 // RUN:     -parse-as-library                               \
 // RUN:     -module-name main                               \
@@ -25,7 +23,53 @@
 // RUN: %target-build-swift-dylib(%t/%target-library-name(Library)) \
 // RUN:     %t/Library.swift                                        \
 // RUN:     -emit-module                                            \
-// RUN:     -target %target-future-triple                   \
+// RUN:     -enable-library-evolution                               \
+// RUN:     -enable-experimental-feature CoroutineAccessors         \
+// RUN:     -emit-module-path %t/Library.swiftmodule                \
+// RUN:     -module-name Library
+
+// RUN: %target-build-swift   \
+// RUN:     %t/Executable.o   \
+// RUN:     -lLibrary         \
+// RUN:     -L %t             \
+// RUN:     %target-rpath(%t) \
+// RUN:     -o %t/main
+
+// RUN: %target-codesign %t/%target-library-name(Library)
+// RUN: %target-codesign %t/main
+// RUN: %target-run %t/main %t/%target-library-name(Library) | %FileCheck %s
+
+// Now do it all again, but without using the runtime
+// swift_task_dealloc_through function.
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend                                \
+// RUN:     -Xllvm -enable-runtime-task-dealloc-through=false \
+// RUN:     %t/Library.swift                                  \
+// RUN:     -emit-module                                      \
+// RUN:     -enable-library-evolution                         \
+// RUN:     -module-name Library                              \
+// RUN:     -enable-experimental-feature CoroutineAccessors   \
+// RUN:     -emit-module-path %t/Library.swiftmodule
+
+// RUN: %target-build-swift                                   \
+// RUN:     -Xllvm -enable-runtime-task-dealloc-through=false \
+// RUN:     %t/Downstream.swift                               \
+// RUN:     -c                                                \
+// RUN:     -Onone                                            \
+// RUN:     -parse-as-library                                 \
+// RUN:     -module-name main                                 \
+// RUN:     -enable-experimental-feature CoroutineAccessors   \
+// RUN:     -lLibrary                                         \
+// RUN:     -I %t                                             \
+// RUN:     -o %t/Executable.o
+
+// RUN: %target-build-swift-dylib(%t/%target-library-name(Library)) \
+// RUN:     -Xllvm -enable-runtime-task-dealloc-through=false       \
+// RUN:     %t/Library.swift                                        \
+// RUN:     -emit-module                                            \
 // RUN:     -enable-library-evolution                               \
 // RUN:     -enable-experimental-feature CoroutineAccessors         \
 // RUN:     -emit-module-path %t/Library.swiftmodule                \
@@ -47,21 +91,20 @@
 // REQUIRES: concurrency_runtime
 
 // TODO: CoroutineAccessors: Enable on WASM.
-// UNSUPPORTED: wasm
-// UNSUPPORTED: OS=wasi
 // UNSUPPORTED: CPU=wasm32
-// TODO: CoroutineAccessors: Enable on Windows.
-// UNSUPPORTED: OS=windows-msvc
 
 // REQUIRES: swift_feature_CoroutineAccessors
 
 //--- Library.swift
 
+// TODO: CoroutineAccessors: Change to X.Y
+@available(SwiftStdlib 9999, *)
 public protocol ResilientWrapping {
   associatedtype Wrapped
   var wrapped: Wrapped { read set }
   var wrapped2: Wrapped { read set }
 }
+@available(SwiftStdlib 9999, *)
 extension ResilientWrapping {
   public var wrapped2: Wrapped {
     read {
@@ -73,6 +116,7 @@ extension ResilientWrapping {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 public struct ResilientBoxtional<T> : ResilientWrapping {
   var storage: T?
   public init(_ t: T?) {
@@ -90,6 +134,7 @@ public struct ResilientBoxtional<T> : ResilientWrapping {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 open class ResilientWrappingClass<Wrapped> {
   public init() {}
   open var wrapped: Wrapped {
@@ -102,6 +147,7 @@ open class ResilientWrappingClass<Wrapped> {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 open class ResilientWrappingSubclass<X : ResilientWrapping> : ResilientWrappingClass<X.Wrapped> {
   public init(_ impl: X) { self.impl = impl }
   var impl: X
@@ -119,6 +165,7 @@ open class ResilientWrappingSubclass<X : ResilientWrapping> : ResilientWrappingC
 
 import Library
 
+@available(SwiftStdlib 9999, *)
 struct MaybePtrBox<T> {
   private var ptr: UnsafeMutablePointer<T>
 
@@ -174,6 +221,7 @@ struct MaybePtrBox<T> {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 struct Boxtional<T> : ResilientWrapping {
   var storage: T?
   init(_ t: T?) {
@@ -191,8 +239,9 @@ struct Boxtional<T> : ResilientWrapping {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 class NonresilientResilientWrappingSubclass<X : ResilientWrapping> : ResilientWrappingClass<X.Wrapped> {
-  init(_ impl: X) { 
+  init(_ impl: X) {
     self.impl = impl
     super.init()
   }
@@ -207,10 +256,12 @@ class NonresilientResilientWrappingSubclass<X : ResilientWrapping> : ResilientWr
   }
 }
 
+@available(SwiftStdlib 9999, *)
 protocol AsyncMutatable {
   mutating func mutate() async
 }
 
+@available(SwiftStdlib 9999, *)
 struct Stringg : AsyncMutatable {
   var value: String
   mutating func mutate() async {
@@ -218,10 +269,12 @@ struct Stringg : AsyncMutatable {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 protocol Mutatable {
   mutating func mutate()
 }
 
+@available(SwiftStdlib 9999, *)
 struct Stringgg : Mutatable {
   var value: String
   mutating func mutate() {
@@ -229,11 +282,13 @@ struct Stringgg : Mutatable {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 protocol Wrapping {
   associatedtype Wrapped
   var wrapped: Wrapped { read set }
 }
 
+@available(SwiftStdlib 9999, *)
 extension MaybePtrBox : Wrapping {
   typealias Wrapped = T?
   var wrapped: T? {
@@ -245,8 +300,10 @@ extension MaybePtrBox : Wrapping {
     }
   }
 }
+@available(SwiftStdlib 9999, *)
 extension MaybePtrBox : ResilientWrapping {}
 
+@available(SwiftStdlib 9999, *)
 class WrappingClass<Wrapped> {
   var wrapped: Wrapped {
     read {
@@ -258,6 +315,7 @@ class WrappingClass<Wrapped> {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 class WrappingSubclass<X : Wrapping> : WrappingClass<X.Wrapped> {
   init(_ impl: X) { self.impl = impl }
   var impl: X
@@ -271,6 +329,7 @@ class WrappingSubclass<X : Wrapping> : WrappingClass<X.Wrapped> {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 extension Optional : Mutatable where Wrapped : Mutatable {
   mutating func mutate() {
     switch (self) {
@@ -283,6 +342,7 @@ extension Optional : Mutatable where Wrapped : Mutatable {
   }
 }
 
+@available(SwiftStdlib 9999, *)
 @main
 struct M {
   static func sync_mutate<T : Mutatable>(_ t: inout T?) {
diff --git a/test/IRGen/runtime_calling_conventions.swift b/test/IRGen/runtime_calling_conventions.swift
index dda42edbc069d..b9bb7ee04e227 100644
--- a/test/IRGen/runtime_calling_conventions.swift
+++ b/test/IRGen/runtime_calling_conventions.swift
@@ -11,7 +11,7 @@ public class C {
 // Check that runtime functions use a proper calling convention.
 // CHECK-NOT: call void {{.*}} @swift_release
 
-// OPT-CHECK-LABEL: define {{(dllexport )?}}{{(protected )?}}swiftcc void @"$s{{(27|28)}}runtime_calling_conventions3fooyyAA1CCF"(ptr nocapture{{.*}} %0)
+// OPT-CHECK-LABEL: define {{(dllexport )?}}{{(protected )?}}swiftcc void @"$s{{(27|28)}}runtime_calling_conventions3fooyyAA1CCF"(ptr{{( nocapture)?}} readnone{{( captures\(none\))?}} %0)
 // Check that runtime functions use a proper calling convention.
 // OPT-CHECK-NOT: tail call void @swift_release
 
diff --git a/test/IRGen/same_type_constraints.swift b/test/IRGen/same_type_constraints.swift
index 4287f34a4c96f..efbcb3f4e4dfe 100644
--- a/test/IRGen/same_type_constraints.swift
+++ b/test/IRGen/same_type_constraints.swift
@@ -67,7 +67,7 @@ where Self : CodingType,
   print(Self.ValueType.self)
 }
 
-// OSIZE: define internal swiftcc ptr @"$s21same_type_constraints12GenericKlazzCyxq_GAA1EAA4DataAaEP_AA0F4TypePWT"(ptr readnone %"GenericKlazz<T, R>.Data", ptr nocapture readonly %"GenericKlazz<T, R>", ptr nocapture readnone %"GenericKlazz<T, R>.E") [[ATTRS:#[0-9]+]] {
+// OSIZE: define internal swiftcc ptr @"$s21same_type_constraints12GenericKlazzCyxq_GAA1EAA4DataAaEP_AA0F4TypePWT"(ptr readnone %"GenericKlazz<T, R>.Data", ptr{{( nocapture)?}} readonly{{( captures\(none\))?}} %"GenericKlazz<T, R>", ptr{{( nocapture)?}} readnone{{( captures\(none\))?}} %"GenericKlazz<T, R>.E") [[ATTRS:#[0-9]+]] {
 // OSIZE: [[ATTRS]] = {{{.*}}noinline
 
 // Check that same-typing two generic parameters together lowers correctly.
diff --git a/test/IRGen/sanitize_coverage.swift b/test/IRGen/sanitize_coverage.swift
index e7090acaab692..dee919b681718 100644
--- a/test/IRGen/sanitize_coverage.swift
+++ b/test/IRGen/sanitize_coverage.swift
@@ -8,8 +8,6 @@
 // RUN: %target-swift-frontend -emit-ir -sanitize=address -sanitize-coverage=edge,indirect-calls %s | %FileCheck %s -check-prefix=SANCOV -check-prefix=SANCOV_INDIRECT_CALLS
 // RUN: %target-swift-frontend -emit-ir -sanitize=address -sanitize-coverage=edge,8bit-counters %s | %FileCheck %s -check-prefix=SANCOV -check-prefix=SANCOV_8BIT_COUNTERS
 // RUN: %target-swift-frontend -emit-ir -sanitize=fuzzer %s | %FileCheck %s -check-prefix=SANCOV -check-prefix=SANCOV_TRACE_CMP
-// These sanitizers aren't supported when targeting Wasm.
-// UNSUPPORTED: wasm
 
 #if canImport(Darwin)
   import Darwin
@@ -19,6 +17,8 @@
   import Android
 #elseif os(Windows)
   import CRT
+#elseif os(WASI)
+  import WASILibc
 #else
 #error("Unsupported platform")
 #endif
diff --git a/test/IRGen/section.swift b/test/IRGen/section.swift
index e7063a088a7e8..89d146ca5ae94 100644
--- a/test/IRGen/section.swift
+++ b/test/IRGen/section.swift
@@ -17,6 +17,10 @@ struct MyStruct {
 	@_section("__TEXT,__mysection") @_used func foo() {}
 }
 
+@_section("__TEXT,__mysection")
+var functionptr = testit
+func testit(_ e: consuming Any) -> Any { e }
+
 // SIL: @_section("__DATA,__mysection") @_hasStorage @_hasInitialValue var g0: Int { get set }
 // SIL: @_section("__DATA,__mysection") @_hasStorage @_hasInitialValue var g1: (Int, Int) { get set }
 // SIL: @_section("__DATA,__mysection") @_hasStorage @_hasInitialValue var g2: Bool { get set }
@@ -28,22 +32,23 @@ struct MyStruct {
 // SIL:   @_section("__DATA,__mysection") @_hasStorage @_hasInitialValue static var static0: Int { get set }
 // SIL:   @_section("__TEXT,__mysection") @_used func foo()
 
-// SIL: sil private [global_init_once_fn] [perf_constraint] @$s7section2g0_WZ : $@convention(c)
+// SIL: sil private [global_init_once_fn] @$s7section2g0_WZ : $@convention(c)
 // SIL: sil hidden [global_init] @$s7section2g0Sivau : $@convention(thin)
-// SIL: sil private [global_init_once_fn] [perf_constraint] @$s7section2g1_WZ : $@convention(c)
+// SIL: sil private [global_init_once_fn] @$s7section2g1_WZ : $@convention(c)
 // SIL: sil hidden [global_init] @$s7section2g1Si_Sitvau : $@convention(thin)
-// SIL: sil private [global_init_once_fn] [perf_constraint] @$s7section2g2_WZ : $@convention(c)
+// SIL: sil private [global_init_once_fn] @$s7section2g2_WZ : $@convention(c)
 // SIL: sil hidden [global_init] @$s7section2g2Sbvau : $@convention(thin)
-// SIL: sil private [global_init_once_fn] [perf_constraint] @$s7section2g3_WZ : $@convention(c)
+// SIL: sil private [global_init_once_fn] @$s7section2g3_WZ : $@convention(c)
 // SIL: sil [global_init] @$s7section2g3Sbvau : $@convention(thin)
-// SIL: sil private [global_init_once_fn] [perf_constraint] @$s7section2g4_WZ : $@convention(c)
+// SIL: sil private [global_init_once_fn] @$s7section2g4_WZ : $@convention(c)
 // SIL: sil hidden [global_init] @$s7section2g4SpySiGSgvau : $@convention(thin)
-// SIL: sil private [global_init_once_fn] [perf_constraint] @$s7section2g5_WZ : $@convention(c)
+// SIL: sil private [global_init_once_fn] @$s7section2g5_WZ : $@convention(c)
 // SIL: sil hidden [global_init] @$s7section2g5SpySiGSgvau : $@convention(thin)
 // SIL: sil hidden [used] [section "__TEXT,__mysection"] @$s7section3fooyyF : $@convention(thin)
-// SIL: sil private [global_init_once_fn] [perf_constraint] @$s7section8MyStructV7static0_WZ : $@convention(c)
+// SIL: sil private [global_init_once_fn] @$s7section8MyStructV7static0_WZ : $@convention(c)
 // SIL: sil hidden [global_init] @$s7section8MyStructV7static0Sivau : $@convention(thin)
 // SIL: sil hidden [used] [section "__TEXT,__mysection"] @$s7section8MyStructV3fooyyF : $@convention(method)
+// SIL: sil hidden @$s7section6testityypypnF : $@convention(thin) (@in Any) -> @out Any {
 
 // IR:  @"$s7section2g0Sivp" = hidden global %TSi <{ {{(i64|i32)}} 1 }>, section "__DATA,__mysection"
 // IR:  @"$s7section2g1Si_Sitvp" = hidden global <{ %TSi, %TSi }> <{ %TSi <{ {{(i64|i32)}} 42 }>, %TSi <{ {{(i64|i32)}} 43 }> }>, section "__DATA,__mysection"
diff --git a/test/IRGen/section_errors.swift b/test/IRGen/section_errors.swift
index 2d7991399a103..fd2bfb5ca1696 100644
--- a/test/IRGen/section_errors.swift
+++ b/test/IRGen/section_errors.swift
@@ -42,7 +42,7 @@ extension MyStruct5 where T == Never {
 @_section("__TEXT,__mysection") // expected-error {{'@_section' attribute cannot be applied to this declaration}}
 struct SomeStruct {}
 
-@_section("") var g1: Int = 1 // expected-error {{@_section section name cannot be empty}}
+@_section("") var g1: Int = 1 // expected-error {{'@_section' section name cannot be empty}}
 
 func function() {
   @_section("__TEXT,__mysection") var l0: Int = 1 // expected-error {{attribute '_section' can only be used in a non-local scope}}
diff --git a/test/IRGen/select_enum.sil b/test/IRGen/select_enum.sil
index 24f8439eb8ff4..a7ef7166cd00a 100644
--- a/test/IRGen/select_enum.sil
+++ b/test/IRGen/select_enum.sil
@@ -7,30 +7,34 @@ enum SinglePayloadSingleEmpty {
   case DataCase(Builtin.Word)
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @select_enum_SinglePayloadSingleEmpty(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @select_enum_SinglePayloadSingleEmpty(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 sil @select_enum_SinglePayloadSingleEmpty : $@convention(thin) (@in SinglePayloadSingleEmpty) -> () {
 bb0(%0 : $*SinglePayloadSingleEmpty):
   %1 = load %0 : $*SinglePayloadSingleEmpty
   // CHECK: [[PAYLOAD1:%[0-9]+]] = load [[WORD_TY:(i32|i64)]], ptr
-  // CHECK: [[TAG1:%[0-9]+]] = load i1, ptr
+  // CHECK: [[TAG1:%[0-9]+]] = load i8, ptr
+  // CHECK: [[TAG1_TRUNC0:%.*]] = icmp eq i8 [[TAG1]], 1
 
   %2 = integer_literal $Builtin.Int32, 2
   %3 = integer_literal $Builtin.Int32, 3
 
-  // CHECK:   select i1 [[TAG1]], i32 2, i32 3
+  // CHECK:   select i1 [[TAG1_TRUNC0]], i32 2, i32 3
   %4 = select_enum %1 : $SinglePayloadSingleEmpty, case #SinglePayloadSingleEmpty.EmptyCase!enumelt: %2, case #SinglePayloadSingleEmpty.DataCase!enumelt: %3 : $Builtin.Int32
 
-  // CHECK: [[V3:%[0-9]+]] = xor i1 [[TAG1]], true
+  // CHECK: [[TAG1_TRUNC1:%.*]] = icmp eq i8 [[TAG1]], 1
+  // CHECK: [[V3:%[0-9]+]] = xor i1 [[TAG1_TRUNC1]], true
   // CHECK-NEXT:   select i1 [[V3]], i32 3, i32 2
   %5 = select_enum %1 : $SinglePayloadSingleEmpty, case #SinglePayloadSingleEmpty.DataCase!enumelt: %3, case #SinglePayloadSingleEmpty.EmptyCase!enumelt: %2 : $Builtin.Int32
 
   // CHECK: [[PAYLOAD0:%[0-9]+]] = load [[WORD_TY:(i32|i64)]], ptr
-  // CHECK: [[TAG0:%[0-9]+]] = load i1, ptr
+  // CHECK: [[TAG0:%[0-9]+]] = load i8, ptr
+  // CHECK: [[TAG0_TRUNC0:%.*]] = icmp eq i8 [[TAG0]], 1
 
-  // CHECK:   select i1 [[TAG0]], i32 2, i32 3
+  // CHECK:   select i1 [[TAG0_TRUNC0]], i32 2, i32 3
   %6 = select_enum_addr %0 : $*SinglePayloadSingleEmpty, case #SinglePayloadSingleEmpty.EmptyCase!enumelt: %2, case #SinglePayloadSingleEmpty.DataCase!enumelt: %3 : $Builtin.Int32
 
-  // CHECK-NEXT:   select i1 [[TAG1]], i32 2, i32 3
+  // CHECK: [[TAG1_TRUNC2:%.*]] = icmp eq i8 [[TAG1]], 1
+  // CHECK-NEXT:   select i1 [[TAG1_TRUNC2]], i32 2, i32 3
   %7 = select_enum %1 : $SinglePayloadSingleEmpty, case #SinglePayloadSingleEmpty.EmptyCase!enumelt: %2, default %3 : $Builtin.Int32
 
   return undef : $()
@@ -45,17 +49,17 @@ enum MyOptional<T> {
 
 sil @select_enum_TwoCasesNoPayload :$ @convention(thin) (@in TwoCasesNoPayload, @in MyOptional<TwoCasesNoPayload>) -> () {
 bb0(%0 : $*TwoCasesNoPayload, %10 : $*MyOptional<TwoCasesNoPayload>):
-// CHECK: [[PAYLOAD1:%[0-9]+]] = load i1, ptr
+// CHECK: [[PAYLOAD1:%[0-9]+]] = load i8, ptr
   %1 = load %0 : $*TwoCasesNoPayload
 
   %2 = integer_literal $Builtin.Int32, 2
   %3 = integer_literal $Builtin.Int32, 42
 
-  // CHECK-NEXT: [[V2:%[0-9]+]] = icmp eq i1 [[PAYLOAD1]], false
+  // CHECK-NEXT: [[V2:%[0-9]+]] = icmp eq i8 [[PAYLOAD1]], 0
   // CHECK-NEXT:   select i1 [[V2]], i32 2, i32 42
   %4 = select_enum %1 : $TwoCasesNoPayload, case #TwoCasesNoPayload.X!enumelt: %2, case #TwoCasesNoPayload.Y!enumelt: %3 : $Builtin.Int32
 
-  // CHECK-NEXT: [[V2:%[0-9]+]] = icmp eq i1 [[PAYLOAD1]], true
+  // CHECK-NEXT: [[V2:%[0-9]+]] = icmp eq i8 [[PAYLOAD1]], 1
   // CHECK-NEXT:   select i1 [[V2]], i32 42, i32 2
   %5 = select_enum %1 : $TwoCasesNoPayload, case #TwoCasesNoPayload.Y!enumelt: %3, default %2 : $Builtin.Int32
 
@@ -82,7 +86,7 @@ enum NoPayloadSingleton {
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i1 @testOptionalOfNoPayloadSingleton(i8 %0)
 sil @testOptionalOfNoPayloadSingleton : $@convention(thin) (MyOptional<NoPayloadSingleton>) -> Builtin.Int1 {
 bb0(%0 : $MyOptional<NoPayloadSingleton>):
-// CHECK:  [[NATIVECCTRUNC:%.*]] = trunc i8 %0 to i1
+// CHECK:  [[NATIVECCTRUNC:%.*]] = icmp eq i8 %0, 1
 // CHECK:  [[NOT:%.*]] = xor i1 [[NATIVECCTRUNC]], true
 // CHECK:  ret i1 [[NOT]]
   %4 = integer_literal $Builtin.Int1, -1          // users: %6, %7
diff --git a/test/IRGen/select_enum_single_payload.sil b/test/IRGen/select_enum_single_payload.sil
index ab56dc7b02ccc..bcd20517cc7d0 100644
--- a/test/IRGen/select_enum_single_payload.sil
+++ b/test/IRGen/select_enum_single_payload.sil
@@ -11,14 +11,15 @@ enum ManyEmptyCases {
     case C(Builtin.Int32)
 }
 
-// CHECK-LABEL-64: define{{( protected)?}} swiftcc i1 @select_enum_A(i64)
+// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i1 @select_enum_A(i64 %0)
 // CHECK-64:  %2 = load i32, ptr %temp-coercion.coerced
-// CHECK-64:  %4 = load i1, ptr %3
+// CHECK-64:  %4 = load i8, ptr %3
 // CHECK-64:  [[PAYLOAD:%.*]] = icmp eq i32 %2, 0
-// CHECK-64:  [[EXTRA:%.*]] = and i1 %4, [[PAYLOAD]]
+// CHECK-64:  [[TAG_TRUNC:%.*]] = icmp eq i8 %4, 1
+// CHECK-64:  [[EXTRA:%.*]] = and i1 [[TAG_TRUNC]], [[PAYLOAD]]
 // CHECK-64:  ret i1 [[EXTRA]]
 
-// CHECK-LABEL-32: define{{( protected)?}} swiftcc i1 @select_enum_A(i32, i8) {{.*}}{
+// CHECK-32-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i1 @select_enum_A(i32 %0, i8 %1) {{.*}}{
 // CHECK-32: entry:
 // CHECK-32:   %2 = trunc i8 %1 to i1
 // CHECK-32:   %3 = icmp eq i32 %0, 0
@@ -32,14 +33,15 @@ entry(%0 : $ManyEmptyCases):
   return %6 : $Builtin.Int1
 }
 
-// CHECK-LABEL-64: define{{( protected)?}} swiftcc i1 @select_enum_B(i64)
+// CHECK-64-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i1 @select_enum_B(i64 %0)
 // CHECK-64:  %2 = load i32, ptr %temp-coercion.coerced
-// CHECK-64:  %4 = load i1, ptr %3
+// CHECK-64:  %4 = load i8, ptr %3
 // CHECK-64:  [[PAYLOAD:%.*]] = icmp eq i32 %2, 1
-// CHECK-64:  [[EXTRA:%.*]] = and i1 %4, [[PAYLOAD]]
+// CHECK-64:  [[TAG_TRUNC:%.*]] = icmp eq i8 %4, 1
+// CHECK-64:  [[EXTRA:%.*]] = and i1 [[TAG_TRUNC]], [[PAYLOAD]]
 // CHECK-64:  ret i1 [[EXTRA]]
 
-// CHECK-LABEL-32: define{{( protected)?}} swiftcc i1 @select_enum_A(i32, i8) {{.*}}{
+// CHECK-32-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i1 @select_enum_B(i32 %0, i8 %1) {{.*}}{
 // CHECK-32: entry:
 // CHECK-32:   %2 = trunc i8 %1 to i1
 // CHECK-32:   %3 = icmp eq i32 %0, 1
diff --git a/test/IRGen/sil_generic_witness_methods.swift b/test/IRGen/sil_generic_witness_methods.swift
index a9c80505798c9..89ed732b726da 100644
--- a/test/IRGen/sil_generic_witness_methods.swift
+++ b/test/IRGen/sil_generic_witness_methods.swift
@@ -34,20 +34,20 @@ func call_methods<T: P, U>(_ x: T, y: S, z: U) {
   x.generic_method(z)
 }
 
-// CHECK-LABEL: define hidden swiftcc void @"$s27sil_generic_witness_methods017call_existential_D0{{[_0-9a-zA-Z]*}}F"(ptr noalias nocapture dereferenceable({{.*}}) %0)
+// CHECK-LABEL: define hidden swiftcc void @"$s27sil_generic_witness_methods017call_existential_D0{{[_0-9a-zA-Z]*}}F"(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %0)
 func call_existential_methods(_ x: P, y: S) {
-  // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds %T27sil_generic_witness_methods1PP, ptr [[X:%0]], i32 0, i32 1
+  // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds{{.*}} %T27sil_generic_witness_methods1PP, ptr [[X:%0]], i32 0, i32 1
   // CHECK: [[METADATA:%.*]] = load ptr, ptr [[METADATA_ADDR]], align 8
-  // CHECK: [[WTABLE_ADDR:%.*]] = getelementptr inbounds %T27sil_generic_witness_methods1PP, ptr [[X]], i32 0, i32 2
+  // CHECK: [[WTABLE_ADDR:%.*]] = getelementptr inbounds{{.*}} %T27sil_generic_witness_methods1PP, ptr [[X]], i32 0, i32 2
   // CHECK: [[WTABLE:%.*]] = load ptr, ptr [[WTABLE_ADDR]], align 8
   // CHECK: [[CONCRETE_METHOD_PTR_GEP:%.*]] = getelementptr inbounds ptr, ptr [[WTABLE]], i32 1
   // CHECK: [[CONCRETE_METHOD_PTR:%.*]] = load ptr, ptr [[CONCRETE_METHOD_PTR_GEP]], align 8
   // CHECK: call swiftcc void [[CONCRETE_METHOD_PTR]](ptr noalias swiftself {{%.*}}, ptr [[METADATA]], ptr [[WTABLE]])
   x.concrete_method()
 
-  // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds %T27sil_generic_witness_methods1PP, ptr [[X]], i32 0, i32 1
+  // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds{{.*}} %T27sil_generic_witness_methods1PP, ptr [[X]], i32 0, i32 1
   // CHECK: [[METADATA:%.*]] = load ptr, ptr [[METADATA_ADDR]], align 8
-  // CHECK: [[WTABLE_ADDR:%.*]] = getelementptr inbounds %T27sil_generic_witness_methods1PP, ptr [[X:%.*]], i32 0, i32 2
+  // CHECK: [[WTABLE_ADDR:%.*]] = getelementptr inbounds{{.*}} %T27sil_generic_witness_methods1PP, ptr [[X:%.*]], i32 0, i32 2
   // CHECK: [[WTABLE:%.*]] = load ptr, ptr [[WTABLE_ADDR]], align 8
   // CHECK: [[GENERIC_METHOD_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[WTABLE]], i32 3
   // CHECK: [[GENERIC_METHOD_PTR:%.*]] = load ptr, ptr [[GENERIC_METHOD_ADDR]], align 8
diff --git a/test/IRGen/sil_witness_methods.sil b/test/IRGen/sil_witness_methods.sil
index 2c2594a76940b..f5ea2e3d65f48 100644
--- a/test/IRGen/sil_witness_methods.sil
+++ b/test/IRGen/sil_witness_methods.sil
@@ -28,14 +28,14 @@ struct X {}
 struct Y {}
 struct Z {}
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @concrete_type_concrete_method_witness(ptr noalias nocapture swiftself %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @concrete_type_concrete_method_witness(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %0, ptr %Self, ptr %SelfWitnessTable)
 sil @concrete_type_concrete_method_witness : $@convention(witness_method: P) (@in Foo) -> @thick Foo.Type {
 entry(%x : $*Foo):
   %m = metatype $@thick Foo.Type
   return %m : $@thick Foo.Type
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @generic_type_concrete_method_witness(ptr noalias nocapture swiftself dereferenceable({{.*}}) %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @generic_type_concrete_method_witness(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{.*}}) %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-objc:    [[T1:%.*]] = getelementptr inbounds ptr, ptr %Self, i64 10
 // CHECK-native:  [[T1:%.*]] = getelementptr inbounds ptr, ptr %Self, i64 7
 // CHECK:         %T = load ptr, ptr [[T1]], align 8
@@ -87,14 +87,14 @@ entry(%x : $@thick Bar<T, U, V>.Type):
 
 // TODO: %Self Type arg is redundant for class method witness
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @concrete_type_generic_method_witness(ptr noalias %0, ptr %Z, ptr noalias nocapture swiftself %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @concrete_type_generic_method_witness(ptr noalias %0, ptr %Z, ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %1, ptr %Self, ptr %SelfWitnessTable)
 sil @concrete_type_generic_method_witness : $@convention(witness_method: P) <Z> (@in Z, @in Foo) -> @thick Foo.Type {
 entry(%z : $*Z, %x : $*Foo):
   %m = metatype $@thick Foo.Type
   return %m : $@thick Foo.Type
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @generic_type_generic_method_witness(ptr noalias %0, ptr %Z, ptr noalias nocapture swiftself dereferenceable(8) %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc ptr @generic_type_generic_method_witness(ptr noalias %0, ptr %Z, ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(8) %1, ptr %Self, ptr %SelfWitnessTable)
 sil @generic_type_generic_method_witness : $@convention(witness_method: P) <T, U, V, Z> (@in Z, @in Bar<T, U, V>) -> @thick Bar<T, U, V>.Type {
 entry(%z : $*Z, %x : $*Bar<T, U, V>):
   %t = metatype $@thick T.Type
@@ -147,7 +147,7 @@ entry:
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @partial_apply_concrete_witness() {{.*}} {
 // CHECK:         [[CONTEXT:%.*]] = call noalias ptr @swift_allocObject({{.*}})
-// CHECK:         [[WTABLE:%.*]] = getelementptr inbounds <{ %swift.refcounted, ptr }>, ptr [[CONTEXT]], i32 0, i32 1
+// CHECK:         [[WTABLE:%.*]] = getelementptr inbounds{{.*}} <{ %swift.refcounted, ptr }>, ptr [[CONTEXT]], i32 0, i32 1
 // CHECK:         store ptr @"$s19sil_witness_methods3BarCyxq_q0_GAA1PAAWP", ptr [[WTABLE]]
 // CHECK:         [[RESULT:%.*]] = insertvalue { ptr, ptr } { ptr @"$s36generic_type_concrete_method_witnessTA", ptr undef }, ptr [[CONTEXT]], 1
 // CHECK:         ret { ptr, ptr } [[RESULT]]
diff --git a/test/IRGen/sil_witness_tables.swift b/test/IRGen/sil_witness_tables.swift
index 0318819450467..4a97794653978 100644
--- a/test/IRGen/sil_witness_tables.swift
+++ b/test/IRGen/sil_witness_tables.swift
@@ -57,15 +57,15 @@ struct Conformer2: Q {
   func qMethod() {}
 }
 
-// CHECK-LABEL: define hidden swiftcc void @"$s18sil_witness_tables7erasure1cAA2QQ_pAA9ConformerV_tF"(ptr noalias nocapture sret({{.*}}) %0)
-// CHECK:         [[WITNESS_TABLE_ADDR:%.*]] = getelementptr inbounds %T18sil_witness_tables2QQP, ptr %0, i32 0, i32 2
+// CHECK-LABEL: define hidden swiftcc void @"$s18sil_witness_tables7erasure1cAA2QQ_pAA9ConformerV_tF"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0)
+// CHECK:         [[WITNESS_TABLE_ADDR:%.*]] = getelementptr inbounds{{.*}} %T18sil_witness_tables2QQP, ptr %0, i32 0, i32 2
 // CHECK-NEXT:    store ptr [[CONFORMER_QQ_WITNESS_TABLE:@"\$s.*WP"]], ptr [[WITNESS_TABLE_ADDR]], align 8
 func erasure(c: Conformer) -> QQ {
   return c
 }
 
-// CHECK-LABEL: define hidden swiftcc void @"$s18sil_witness_tables15externalErasure1c0a1_b1_c1_D12_conformance9ExternalP_pAD0G9ConformerV_tF"(ptr noalias nocapture sret({{.*}}) %0)
-// CHECK:         [[WITNESS_TABLE_ADDR:%.*]] = getelementptr inbounds %T39sil_witness_tables_external_conformance9ExternalPP, ptr %0, i32 0, i32 2
+// CHECK-LABEL: define hidden swiftcc void @"$s18sil_witness_tables15externalErasure1c0a1_b1_c1_D12_conformance9ExternalP_pAD0G9ConformerV_tF"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0)
+// CHECK:         [[WITNESS_TABLE_ADDR:%.*]] = getelementptr inbounds{{.*}} %T39sil_witness_tables_external_conformance9ExternalPP, ptr %0, i32 0, i32 2
 // CHECK-NEXT:    store ptr [[EXTERNAL_CONFORMER_EXTERNAL_P_WITNESS_TABLE]], ptr %2, align 8
 func externalErasure(c: ExternalConformer) -> ExternalP {
   return c
diff --git a/test/IRGen/static-libclosure.swift b/test/IRGen/static-libclosure.swift
new file mode 100644
index 0000000000000..9e2862a9e4ed4
--- /dev/null
+++ b/test/IRGen/static-libclosure.swift
@@ -0,0 +1,9 @@
+// RUN: %swift_frontend_plain -target x86_64-unknown-windows-msvc -primary-file %s -parse-as-library -parse-stdlib -nostdimport -module-name M -emit-ir -Xcc -static-libclosure -o - | %FileCheck %s
+
+public let block: @convention(block) () -> () = {
+}
+
+// CHECK-NOT: @_NSConcreteStackBlock = external dllimport global
+// CHECK-NOT: declare dllimport ptr @_Block_copy(ptr)
+// CHECK: @_NSConcreteStackBlock = external global
+// CHECK: declare ptr @_Block_copy(ptr)
diff --git a/test/IRGen/static_initializer.sil b/test/IRGen/static_initializer.sil
index d4cb6849cff87..efbc90834ba19 100644
--- a/test/IRGen/static_initializer.sil
+++ b/test/IRGen/static_initializer.sil
@@ -1,6 +1,9 @@
 // RUN: %target-swift-frontend %s -emit-ir | %FileCheck %s -check-prefix CHECK -check-prefix CHECK-%target-abi -check-prefix CHECK-%target-abi-%target-cpu
 
-// REQUIRES: CPU=arm64 || CPU=x86_64
+// REQUIRES: CPU=aarch64 || CPU=arm64 || CPU=x86_64
+
+// Android x86_64 doesn't expose Float80.
+// UNSUPPORTED: OS=linux-android && CPU=x86_64
 
 // Generated from
 // var x : Int32 = 2
@@ -95,7 +98,7 @@ sil_global @static_optional_int_vector : $Optional<Int32> = {
   %8 = enum $Optional<Int32>, #Optional.some!enumelt, %5 : $Int32
   %initval = vector (%6 : $Optional<Int32>, %7 : $Optional<Int32>, %8 : $Optional<Int32>)
 }
-// CHECK: @static_optional_int_vector = {{(dllexport )?}}{{(protected )?}}global [3 x <{ i32, i1, i8, i8, i8 }>] [<{ i32, i1, i8, i8, i8 }> <{ i32 2, i1 false, i8 undef, i8 undef, i8 undef }>, <{ i32, i1, i8, i8, i8 }> <{ i32 10, i1 false, i8 undef, i8 undef, i8 undef }>, <{ i32, i1, i8, i8, i8 }> <{ i32 20, i1 false, i8 undef, i8 undef, i8 undef }>], align 4
+// CHECK: @static_optional_int_vector = {{(dllexport )?}}{{(protected )?}}global [3 x <{ i32, i8, i8, i8, i8 }>] [<{ i32, i8, i8, i8, i8 }> <{ i32 2, i8 0, i8 undef, i8 undef, i8 undef }>, <{ i32, i8, i8, i8, i8 }> <{ i32 10, i8 0, i8 undef, i8 undef, i8 undef }>, <{ i32, i8, i8, i8, i8 }> <{ i32 20, i8 0, i8 undef, i8 undef, i8 undef }>], align 4
 
 sil_global @static_aligned_array : $TestArrayStorage = {
   %0 = integer_literal $Builtin.Int32, 2
@@ -187,8 +190,8 @@ bb0:
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { i64, i32 } @"$s6nested1fAA2S2VyF"() {{.*}} {
 // CHECK-NEXT: entry:
 // CHECK: load i32, ptr @"$s6nested1xAA2S2Vv"
-// CHECK-NEXT: load i32, ptr getelementptr inbounds (%T18static_initializer2S2V, ptr @"$s6nested1xAA2S2Vv", i32 0, i32 1)
-// CHECK-NEXT: load i32, ptr getelementptr inbounds (%T18static_initializer2S2V, ptr @"$s6nested1xAA2S2Vv", i32 0, i32 2)
+// CHECK-NEXT: load i32, ptr getelementptr inbounds{{.*}} (%T18static_initializer2S2V, ptr @"$s6nested1xAA2S2Vv", i32 0, i32 1)
+// CHECK-NEXT: load i32, ptr getelementptr inbounds{{.*}} (%T18static_initializer2S2V, ptr @"$s6nested1xAA2S2Vv", i32 0, i32 2)
 sil @$s6nested1fAA2S2VyF : $@convention(thin) () -> S2 {
 bb0:
   %0 = global_addr @$s6nested1xAA2S2Vv : $*S2
diff --git a/test/IRGen/stdlib/Mutex.swift b/test/IRGen/stdlib/Mutex.swift
index c086008658f32..2791e6456d8b8 100644
--- a/test/IRGen/stdlib/Mutex.swift
+++ b/test/IRGen/stdlib/Mutex.swift
@@ -31,8 +31,8 @@ final class Awaitable<Value, Failure>: Sendable where Value: Sendable, Failure:
 }
 
 // CHECK: define {{.*}} ptr @"$s15Synchronization5MutexVy6stdlib9AwaitableC5StateVyxq__GGs8SendableRzs5ErrorR_r0_lWOb"(ptr [[SRC:%.*]], ptr [[DEST:%.*]], ptr {{%.*}}, ptr {{%.*}}, ptr {{%.*}}, ptr {{%.*}}, ptr {{%.*}}, ptr {{%.*}}, ptr [[MUTEX:%.*]])
-// CHECK:   [[DEST_HANDLE_PTR:%.*]] = getelementptr inbounds %T15Synchronization5MutexV{{.*}}, ptr [[DEST]], i32 0, i32 0
-// CHECK:   [[SRC_HANDLE_PTR:%.*]] = getelementptr inbounds %T15Synchronization5MutexV{{.*}}, ptr [[SRC]], i32 0, i32 0
+// CHECK:   [[DEST_HANDLE_PTR:%.*]] = getelementptr inbounds{{.*}} %T15Synchronization5MutexV{{.*}}, ptr [[DEST]], i32 0, i32 0
+// CHECK:   [[SRC_HANDLE_PTR:%.*]] = getelementptr inbounds{{.*}} %T15Synchronization5MutexV{{.*}}, ptr [[SRC]], i32 0, i32 0
 // CHECK:   call void @llvm.memcpy.p0.p0.i{{32|64}}(ptr {{.*}} [[DEST_HANDLE_PTR]], ptr {{.*}} [[SRC_HANDLE_PTR]], i{{32|64}} {{.*}}, i1 false)
 // CHECK:   [[DEST_MUTEX_VALUE_OFFSET_PTR:%.*]] = getelementptr inbounds i32, ptr [[MUTEX]], i{{32 4|64 7}}
 // CHECK:   [[DEST_MUTEX_VALUE_OFFSET:%.*]] = load i32, ptr [[DEST_MUTEX_VALUE_OFFSET_PTR]]
@@ -42,5 +42,5 @@ final class Awaitable<Value, Failure>: Sendable where Value: Sendable, Failure:
 // CHECK:   [[SRC_VALUE_PTR:%.*]] = getelementptr inbounds i8, ptr [[SRC]], i32 [[SRC_MUTEX_VALUE_OFFSET]]
 
 // These GEPs used to cause compiler crashes because they were incorrectly typed...
-// CHECK:   [[DEST_PENDING_CONSUMERS_PTR:%.*]] = getelementptr inbounds %T6stdlib9AwaitableC5StateV{{.*}}, ptr [[DEST_VALUE_PTR]], i32 0, i32 0
-// CHECK:   [[SRC_PENDING_CONSUMERS_PTR:%.*]] = getelementptr inbounds %T6stdlib9AwaitableC5StateV{{.*}}, ptr [[SRC_VALUE_PTR]], i32 0, i32 0
+// CHECK:   [[DEST_PENDING_CONSUMERS_PTR:%.*]] = getelementptr inbounds{{.*}} %T6stdlib9AwaitableC5StateV{{.*}}, ptr [[DEST_VALUE_PTR]], i32 0, i32 0
+// CHECK:   [[SRC_PENDING_CONSUMERS_PTR:%.*]] = getelementptr inbounds{{.*}} %T6stdlib9AwaitableC5StateV{{.*}}, ptr [[SRC_VALUE_PTR]], i32 0, i32 0
diff --git a/test/IRGen/struct_resilience.swift b/test/IRGen/struct_resilience.swift
index 73960b0340bae..e717ce3610d74 100644
--- a/test/IRGen/struct_resilience.swift
+++ b/test/IRGen/struct_resilience.swift
@@ -26,7 +26,7 @@ public func functionWithResilientTypesSize(_ s: __owned Size, f: (__owned Size)
 // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
 // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
 
-// CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+// CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
 // CHECK: [[WITNESS_FOR_SIZE:%.*]] = load [[INT]], ptr [[WITNESS_ADDR]]
 // CHECK: [[ALLOCA:%.*]] = alloca i8, {{.*}} [[WITNESS_FOR_SIZE]], align 16
 
@@ -62,7 +62,7 @@ public func functionWithResilientTypesRectangle(_ r: Rectangle) {
 // CHECK-NEXT: [[FIELD_OFFSET_PTR:%.*]] = getelementptr inbounds i32, ptr [[METADATA]], [[INT]] [[IDX:2|4|6]]
 // CHECK-NEXT: [[FIELD_OFFSET:%.*]] = load i32, ptr [[FIELD_OFFSET_PTR]]
 // CHECK-NEXT: [[FIELD_ADDR:%.*]] = getelementptr inbounds i8, ptr %0, i32 [[FIELD_OFFSET]]
-// CHECK-NEXT: [[FIELD_PAYLOAD_PTR:%.*]] = getelementptr inbounds %TSi, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[FIELD_PAYLOAD_PTR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[FIELD_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = load [[INT]], ptr [[FIELD_PAYLOAD_PTR]]
 
   _ = r.color
@@ -80,7 +80,7 @@ public struct MySize {
   public let h: Int
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s17struct_resilience32functionWithMyResilientTypesSize_1fAA0eH0VAEn_A2EnXEtF"(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{8|(16)}}) %1, ptr %2, ptr %3)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s17struct_resilience32functionWithMyResilientTypesSize_1fAA0eH0VAEn_A2EnXEtF"(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{8|(16)}}) %1, ptr %2, ptr %3)
 public func functionWithMyResilientTypesSize(_ s: __owned MySize, f: (__owned MySize) -> MySize) -> MySize {
 
 // There's an alloca for debug info?
@@ -88,27 +88,27 @@ public func functionWithMyResilientTypesSize(_ s: __owned MySize, f: (__owned My
 
 // CHECK: [[DST:%.*]] = alloca %T17struct_resilience6MySizeV
 
-// CHECK: [[W_ADDR:%.*]] = getelementptr inbounds %T17struct_resilience6MySizeV, ptr %1, i32 0, i32 0
-// CHECK: [[W_PTR:%.*]] = getelementptr inbounds %TSi, ptr [[W_ADDR]], i32 0, i32 0
+// CHECK: [[W_ADDR:%.*]] = getelementptr inbounds{{.*}} %T17struct_resilience6MySizeV, ptr %1, i32 0, i32 0
+// CHECK: [[W_PTR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[W_ADDR]], i32 0, i32 0
 // CHECK: [[W:%.*]] = load [[INT]], ptr [[W_PTR]]
 
-// CHECK: [[H_ADDR:%.*]] = getelementptr inbounds %T17struct_resilience6MySizeV, ptr %1, i32 0, i32 1
-// CHECK: [[H_PTR:%.*]] = getelementptr inbounds %TSi, ptr [[H_ADDR]], i32 0, i32 0
+// CHECK: [[H_ADDR:%.*]] = getelementptr inbounds{{.*}} %T17struct_resilience6MySizeV, ptr %1, i32 0, i32 1
+// CHECK: [[H_PTR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[H_ADDR]], i32 0, i32 0
 // CHECK: [[H:%.*]] = load [[INT]], ptr [[H_PTR]]
 
 
 // CHECK: call void @llvm.lifetime.start.p0({{i32|i64}} {{8|16}}, ptr [[DST]])
 
-// CHECK: [[W_ADDR:%.*]] = getelementptr inbounds %T17struct_resilience6MySizeV, ptr [[DST]], i32 0, i32 0
-// CHECK: [[W_PTR:%.*]] = getelementptr inbounds %TSi, ptr [[W_ADDR]], i32 0, i32 0
+// CHECK: [[W_ADDR:%.*]] = getelementptr inbounds{{.*}} %T17struct_resilience6MySizeV, ptr [[DST]], i32 0, i32 0
+// CHECK: [[W_PTR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[W_ADDR]], i32 0, i32 0
 // CHECK: store [[INT]] [[W]], ptr [[W_PTR]]
 
-// CHECK: [[H_ADDR:%.*]] = getelementptr inbounds %T17struct_resilience6MySizeV, ptr [[DST]], i32 0, i32 1
-// CHECK: [[H_PTR:%.*]] = getelementptr inbounds %TSi, ptr [[H_ADDR]], i32 0, i32 0
+// CHECK: [[H_ADDR:%.*]] = getelementptr inbounds{{.*}} %T17struct_resilience6MySizeV, ptr [[DST]], i32 0, i32 1
+// CHECK: [[H_PTR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[H_ADDR]], i32 0, i32 0
 // CHECK: store [[INT]] [[H]], ptr [[H_PTR]]
 
 
-// CHECK: call swiftcc void %2(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{8|16}}) [[DST]], ptr swiftself %3)
+// CHECK: call swiftcc void %2(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{8|16}}) [[DST]], ptr swiftself %3)
 // CHECK: call void @llvm.lifetime.end.p0({{i32|i64}} {{8|16}}, ptr [[DST]])
 
 // CHECK: ret void
@@ -136,7 +136,7 @@ public struct StructWithResilientStorage {
 // CHECK-NEXT: [[FIELD_OFFSET_PTR:%.*]] = getelementptr inbounds i32, ptr [[METADATA]], [[INT]] [[IDX:2|4|6]]
 // CHECK-NEXT: [[FIELD_OFFSET:%.*]] = load i32, ptr [[FIELD_OFFSET_PTR]]
 // CHECK-NEXT: [[FIELD_ADDR:%.*]] = getelementptr inbounds i8, ptr %0, i32 [[FIELD_OFFSET]]
-// CHECK-NEXT: [[FIELD_PAYLOAD_PTR:%.*]] = getelementptr inbounds %TSi, ptr [[FIELD_ADDR]], i32 0, i32 0
+// CHECK-NEXT: [[FIELD_PAYLOAD_PTR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[FIELD_ADDR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = load [[INT]], ptr [[FIELD_PAYLOAD_PTR]]
 // CHECK-NEXT: ret [[INT]] [[FIELD_PAYLOAD]]
 
@@ -150,8 +150,8 @@ public struct StructWithIndirectResilientEnum {
 
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc {{i32|i64}} @"$s17struct_resilience31StructWithIndirectResilientEnumV1nSivg"(ptr {{.*}})
-// CHECK:      [[FIELD_PTR:%.*]] = getelementptr inbounds %T17struct_resilience31StructWithIndirectResilientEnumV, ptr %0, i32 0, i32 1
-// CHECK-NEXT: [[FIELD_PAYLOAD_PTR:%.*]] = getelementptr inbounds %TSi, ptr [[FIELD_PTR]], i32 0, i32 0
+// CHECK:      [[FIELD_PTR:%.*]] = getelementptr inbounds{{.*}} %T17struct_resilience31StructWithIndirectResilientEnumV, ptr %0, i32 0, i32 1
+// CHECK-NEXT: [[FIELD_PAYLOAD_PTR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[FIELD_PTR]], i32 0, i32 0
 // CHECK-NEXT: [[FIELD_PAYLOAD:%.*]] = load [[INT]], ptr [[FIELD_PAYLOAD_PTR]]
 // CHECK:      ret [[INT]] [[FIELD_PAYLOAD]]
 
@@ -164,7 +164,7 @@ public struct ResilientStructWithMethod {
 
 // Corner case -- type is address-only in SIL, but empty in IRGen
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s17struct_resilience29partialApplyOfResilientMethod1ryAA0f10StructWithG0V_tF"(ptr noalias nocapture %0)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s17struct_resilience29partialApplyOfResilientMethod1ryAA0f10StructWithG0V_tF"(ptr noalias {{(nocapture|captures\(none\))}} %0)
 public func partialApplyOfResilientMethod(r: ResilientStructWithMethod) {
   _ = r.method
 }
@@ -187,10 +187,10 @@ public func resilientAny(s : ResilientWeakRef) {
 // CHECK: [[ANY:%.*]] = alloca %Any
 // CHECK: [[META:%.*]] = call swiftcc %swift.metadata_response @"$s16resilient_struct16ResilientWeakRefVMa"([[INT]] 0)
 // CHECK: [[META2:%.*]] = extractvalue %swift.metadata_response [[META]], 0
-// CHECK: [[TYADDR:%.*]] = getelementptr inbounds %Any, ptr [[ANY]], i32 0, i32 1
+// CHECK: [[TYADDR:%.*]] = getelementptr inbounds{{.*}} %Any, ptr [[ANY]], i32 0, i32 1
 // CHECK: store ptr [[META2]], ptr [[TYADDR]]
 // CHECK: call ptr @__swift_allocate_boxed_opaque_existential_0(ptr [[ANY]])
-// CHECK: call swiftcc void @"$s17struct_resilience8wantsAnyyyypF"(ptr noalias nocapture dereferenceable({{(32|16)}}) [[ANY]])
+// CHECK: call swiftcc void @"$s17struct_resilience8wantsAnyyyypF"(ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{(32|16)}}) [[ANY]])
 // CHECK: call void @__swift_destroy_boxed_opaque_existential_0(ptr [[ANY]])
 // CHECK: ret void
 
@@ -208,7 +208,7 @@ public func memoryLayoutDotSizeWithResilientStruct() -> Int {
   // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
   // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
 
-  // CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 8
+  // CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 8
   // CHECK: [[WITNESS_FOR_SIZE:%.*]] = load [[INT]], ptr [[WITNESS_ADDR]]
 
   // CHECK: ret [[INT]] [[WITNESS_FOR_SIZE]]
@@ -226,7 +226,7 @@ public func memoryLayoutDotStrideWithResilientStruct() -> Int {
   // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
   // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
 
-  // CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 9
+  // CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 9
   // CHECK: [[WITNESS_FOR_STRIDE:%.*]] = load [[INT]], ptr [[WITNESS_ADDR]]
 
   // CHECK: ret [[INT]] [[WITNESS_FOR_STRIDE]]
@@ -244,7 +244,7 @@ public func memoryLayoutDotAlignmentWithResilientStruct() -> Int {
   // CHECK-arm64e-NEXT: call i64 @llvm.ptrauth.blend
   // CHECK-arm64e: [[VWT:%.*]] = inttoptr i64 {{%.*}} to ptr
 
-  // CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], i32 0, i32 10
+  // CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable, ptr [[VWT]], i32 0, i32 10
   // CHECK: [[WITNESS_FOR_FLAGS:%.*]] = load i32, ptr [[WITNESS_ADDR]]
 
   // Not checked because it only exists on 64-bit: [[EXTENDED_FLAGS:%.*]] = zext i32 [[WITNESS_FOR_FLAGS]] to [[INT]]
@@ -286,7 +286,7 @@ public func memoryLayoutDotOffsetOfWithResilientStruct() -> Int? {
 // CHECK: [[FIELDS:%.*]] = alloca [4 x ptr]
 // CHECK: [[TUPLE_LAYOUT:%.*]] = alloca %swift.full_type_layout,
 
-// CHECK: [[FIELDS_ADDR:%.*]] = getelementptr inbounds [4 x ptr], ptr [[FIELDS]], i32 0, i32 0
+// CHECK: [[FIELDS_ADDR:%.*]] = getelementptr inbounds{{.*}} [4 x ptr], ptr [[FIELDS]], i32 0, i32 0
 
 // public let s: Size
 
diff --git a/test/IRGen/struct_with_resilient_type.swift b/test/IRGen/struct_with_resilient_type.swift
index 20bc54a4cfa0b..91d05a40cf79c 100644
--- a/test/IRGen/struct_with_resilient_type.swift
+++ b/test/IRGen/struct_with_resilient_type.swift
@@ -44,17 +44,17 @@ crashCaller()
 
 // Don't use the type layout based value witness based generation (i.e we load field offsets below).
 
-// VWT-macosx: define {{.*}} ptr @"$s26struct_with_resilient_type9SomeValueVwta"(ptr noalias returned {{.*}}, ptr noalias {{.*}}, ptr nocapture readonly [[MT:%.*]])
+// VWT-macosx: define {{.*}} ptr @"$s26struct_with_resilient_type9SomeValueVwta"(ptr noalias returned {{.*}}, ptr noalias {{.*}}, ptr{{( nocapture)?}} readonly{{( captures\(none\))?}} [[MT:%.*]])
 // VWT-macosx:   [[VAL1:%.*]] = load i64
 // VWT-macosx:   store i64 [[VAL1]]
 // VWT-macosx:   [[T1:%.*]] = tail call swiftcc %swift.metadata_response @"$s16resilient_struct13ResilientBoolVMa"(i64 0)
 // VWT-macosx:   [[T2:%.*]] = extractvalue %swift.metadata_response [[T1]], 0
 // VWT-macosx:   [[T3:%.*]] = getelementptr inbounds i8, ptr [[T2]], i64 -8
 // VWT-macosx:   [[T5:%.*]] = load ptr, ptr [[T3]]
-// VWT-macosx:   [[T6:%.*]] = getelementptr inbounds i8, ptr [[T5]], i64 4
+// VWT-macosx:   [[T6:%.*]] = getelementptr inbounds{{.*}} i8, ptr [[T5]], i64 4
 // VWT-macosx:   [[T8:%.*]] = load ptr, ptr [[T6]]
 // VWT-macosx:   tail call ptr [[T8]](
-// VWT-macosx:   [[F01:%.*]] = getelementptr inbounds i8, ptr [[MT]], i64 24
+// VWT-macosx:   [[F01:%.*]] = getelementptr inbounds{{.*}} i8, ptr [[MT]], i64 24
 // VWT-macosx:   [[F03:%.*]] = load i32, ptr [[F01]], align 8
 // VWT-macosx:   [[F04:%.*]] = sext i32 [[F03]] to i64
 // VWT-macosx:   [[FA1:%.*]] = getelementptr inbounds i8, ptr {{.*}}, i64 [[F04]]
diff --git a/test/IRGen/temporary_allocation/codegen.swift b/test/IRGen/temporary_allocation/codegen.swift
index ba2c430279a08..51f047c0e69cd 100644
--- a/test/IRGen/temporary_allocation/codegen.swift
+++ b/test/IRGen/temporary_allocation/codegen.swift
@@ -1,5 +1,5 @@
 // RUN: %target-swift-frontend -primary-file %s -O -emit-ir | %FileCheck %s
-// REQUIRES: swift_stdlib_no_asserts,optimized_stdlib
+// REQUIRES: optimized_stdlib
 
 @_silgen_name("blackHole")
 func blackHole(_ value: UnsafeMutableRawPointer?) -> Void
@@ -16,10 +16,10 @@ do {
 // CHECK: [[ONE_BYTE_PTR_RAW:%temp_alloc[0-9]*]] = alloca i8, align 1
 // CHECK: [[FIVE_BYTE_PTR_RAW:%temp_alloc[0-9]*]] = alloca [5 x i8], align 1
 // CHECK: [[ONE_KB_PTR_RAW:%temp_alloc[0-9]*]] = alloca [1024 x i8], align 8
-// CHECK: [[ONE_KB_RAND_PTR_RAW:%temp_alloc[0-9]*]] = alloca [1024 x i8], align 16
 // CHECK: [[INT_PTR_RAW:%temp_alloc[0-9]*]] = alloca [16 x i8], align 4
 // CHECK: [[INT_PTR_RAW2:%temp_alloc[0-9]*]] = alloca [16 x i8], align 4
 // CHECK: [[VOID_PTR_RAW:%temp_alloc[0-9]*]] = alloca [2 x i8], align 1
+// CHECK: [[ONE_KB_RAND_PTR_RAW:%temp_alloc[0-9]*]] = alloca [1024 x i8], align 16
 
 // CHECK: ptrtoint ptr {{.*}} to [[WORD:i[0-9]+]]
 
@@ -49,14 +49,6 @@ withUnsafeTemporaryAllocation(byteCount: 1024, alignment: 8) { buffer in
 // CHECK: [[ONE_KB_PTR:%[0-9]+]] = ptrtoint ptr [[ONE_KB_PTR_RAW]] to [[WORD]]
 // CHECK: call swiftcc void @blackHole([[WORD]] [[ONE_KB_PTR]])
 
-// MARK: Alignment unknown at compile-time
-
-withUnsafeTemporaryAllocation(byteCount: 1024, alignment: Int.random(in: 0 ..< 16)) { buffer in
-  blackHole(buffer.baseAddress)
-}
-// CHECK: [[ONE_KB_RAND_PTR:%[0-9]+]] = ptrtoint ptr [[ONE_KB_RAND_PTR_RAW]] to [[WORD]]
-// CHECK: call swiftcc void @blackHole([[WORD]] [[ONE_KB_RAND_PTR]])
-
 // MARK: Typed buffers
 
 withUnsafeTemporaryAllocation(of: Int32.self, capacity: 4) { buffer in
@@ -77,3 +69,10 @@ withUnsafeTemporaryAllocation(of: Void.self, capacity: 2) { buffer in
 // CHECK: [[VOID_PTR:%[0-9]+]] = ptrtoint ptr [[VOID_PTR_RAW]] to [[WORD]]
 // CHECK: call swiftcc void @blackHole([[WORD]] [[VOID_PTR]])
 
+// MARK: Alignment unknown at compile-time
+
+withUnsafeTemporaryAllocation(byteCount: 1024, alignment: Int.random(in: 0 ..< 16)) { buffer in
+  blackHole(buffer.baseAddress)
+}
+// CHECK: [[ONE_KB_RAND_PTR:%[0-9]+]] = ptrtoint ptr [[ONE_KB_RAND_PTR_RAW]] to [[WORD]]
+// CHECK: call swiftcc void @blackHole([[WORD]] [[ONE_KB_RAND_PTR]])
diff --git a/test/IRGen/temporary_allocation/codegen_very_large_allocation.swift b/test/IRGen/temporary_allocation/codegen_very_large_allocation.swift
index 116f061dd1b7d..c5540d31762e2 100644
--- a/test/IRGen/temporary_allocation/codegen_very_large_allocation.swift
+++ b/test/IRGen/temporary_allocation/codegen_very_large_allocation.swift
@@ -10,6 +10,10 @@
 // On iOS _stdlib_isOSVersionAtLeast() is @_transparent, which affects codegen.
 // UNSUPPORTED: OS=ios
 
+// When macCatalyst support is enabled, isOSVersionAtLeast transforms into
+// isOSVersionAtLeastOrVariantVersionAtLeast
+// UNSUPPORTED: maccatalyst_support
+
 @_silgen_name("blackHole")
 func blackHole(_ value: UnsafeMutableRawPointer?) -> Void
 
diff --git a/test/IRGen/typed_boxes.sil b/test/IRGen/typed_boxes.sil
index cebe4838b4841..b14e322bdd805 100644
--- a/test/IRGen/typed_boxes.sil
+++ b/test/IRGen/typed_boxes.sil
@@ -9,7 +9,7 @@ sil @pod_box_8_8_a : $@convention(thin) () -> () {
 entry:
   // CHECK: [[BOX:%.*]] = call noalias ptr @swift_allocObject(ptr {{.*}} [[POD_8_8_METADATA:@metadata[0-9.]*]], i32 0, i32 2), [[WORD:i[0-9]+]] [[POD_8_8_SIZE:[0-9]+]], [[WORD]] 7)
   %a = alloc_box $<τ_0_0> { var τ_0_0 } <Builtin.Int64>
-  // CHECK: [[BOX_DATA:%.*]] = getelementptr inbounds [[POD_8_8_LAYOUT:<\{ %swift.refcounted, \[8 x i8\] \}>]], ptr [[BOX]], i32 0, i32 1
+  // CHECK: [[BOX_DATA:%.*]] = getelementptr inbounds{{.*}} [[POD_8_8_LAYOUT:<\{ %swift.refcounted, \[8 x i8\] \}>]], ptr [[BOX]], i32 0, i32 1
   %b = project_box %a : $<τ_0_0> { var τ_0_0 } <Builtin.Int64>, 0
   // CHECK: call void @swift_deallocUninitializedObject(ptr [[BOX]], [[WORD]] [[POD_8_8_SIZE]], [[WORD]] 7)
   dealloc_box %a : $<τ_0_0> { var τ_0_0 } <Builtin.Int64>
@@ -21,7 +21,7 @@ sil @pod_box_8_8_b : $@convention(thin) () -> () {
 entry:
   // CHECK: [[BOX:%.*]] = call noalias ptr @swift_allocObject(ptr {{.*}} [[POD_8_8_METADATA]], i32 0, i32 2), [[WORD]] [[POD_8_8_SIZE]], [[WORD]] 7)
   %a = alloc_box $<τ_0_0> { var τ_0_0 } <Builtin.FPIEEE64>
-  // CHECK: [[BOX_DATA:%.*]] = getelementptr inbounds [[POD_8_8_LAYOUT]], ptr [[BOX]], i32 0, i32 1
+  // CHECK: [[BOX_DATA:%.*]] = getelementptr inbounds{{.*}} [[POD_8_8_LAYOUT]], ptr [[BOX]], i32 0, i32 1
   %b = project_box %a : $<τ_0_0> { var τ_0_0 } <Builtin.FPIEEE64>, 0
   // CHECK: call void @swift_deallocUninitializedObject(ptr [[BOX]], [[WORD]] [[POD_8_8_SIZE]], [[WORD]] 7)
   dealloc_box %a : $<τ_0_0> { var τ_0_0 } <Builtin.FPIEEE64>
@@ -38,7 +38,7 @@ sil @pod_box_32_16 : $@convention(thin) () -> () {
 entry:
   // CHECK: [[BOX:%.*]] = call noalias ptr @swift_allocObject(ptr {{.*}} [[POD_32_16_METADATA:@metadata[0-9.]*]], {{.*}} [[WORD]] 48, [[WORD]] 15)
   %a = alloc_box $<τ_0_0> { var τ_0_0 } <OverAligned>
-  // CHECK-32: [[BOX_DATA:%.*]] = getelementptr inbounds [[POD_32_16_LAYOUT:<\{ %swift.refcounted, \[8 x i8\], \[32 x i8\] \}>]], ptr [[BOX]], i32 0, i32 2
+  // CHECK-32: [[BOX_DATA:%.*]] = getelementptr inbounds{{.*}} [[POD_32_16_LAYOUT:<\{ %swift.refcounted, \[8 x i8\], \[32 x i8\] \}>]], ptr [[BOX]], i32 0, i32 2
   %b = project_box %a : $<τ_0_0> { var τ_0_0 } <OverAligned>, 0
   // CHECK: call void @swift_deallocUninitializedObject(ptr [[BOX]], [[WORD]] 48, [[WORD]] 15)
   dealloc_box %a : $<τ_0_0> { var τ_0_0 } <OverAligned>
@@ -145,7 +145,7 @@ entry:
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc i64 @proj_box
 sil @proj_box : $@convention(thin) (<τ_0_0> { var τ_0_0 } <Builtin.Int64>) -> Builtin.Int64 {
 entry(%0 : $<τ_0_0> { var τ_0_0 } <Builtin.Int64>):
-  // CHECK: [[BOX_DATA:%.*]] = getelementptr inbounds [[POD_8_8_LAYOUT]], ptr %0, i32 0, i32 1
+  // CHECK: [[BOX_DATA:%.*]] = getelementptr inbounds{{.*}} [[POD_8_8_LAYOUT]], ptr %0, i32 0, i32 1
   %p = project_box %0 : $<τ_0_0> { var τ_0_0 } <Builtin.Int64>, 0
   // CHECK: [[R:%.*]] = load i64, ptr [[BOX_DATA]]
   %l = load %p : $*Builtin.Int64
diff --git a/test/IRGen/typed_throws.sil b/test/IRGen/typed_throws.sil
index 8d5caa462ee53..799c6bc06b2d1 100644
--- a/test/IRGen/typed_throws.sil
+++ b/test/IRGen/typed_throws.sil
@@ -18,7 +18,7 @@ sil_vtable A {}
 
 sil @create_error : $@convention(thin) () -> @owned A
 
-// CHECK: define{{.*}} swiftcc { ptr, ptr } @throw_error(ptr swiftself %0, ptr noalias nocapture swifterror dereferenceable({{.*}}) %1)
+// CHECK: define{{.*}} swiftcc { ptr, ptr } @throw_error(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.*}}) %1)
 // CHECK:   [[ERR:%.*]] = call swiftcc ptr @create_error()
 // CHECK:   call ptr @swift_retain(ptr returned [[ERR]])
 // CHECK:   store ptr inttoptr (i64 1 to ptr), ptr %1
@@ -47,7 +47,7 @@ sil @try_apply_helper : $@convention(thin) (@owned AnyObject) -> (@owned AnyObje
 // CHECK: entry:
 // CHECK:   %swifterror = alloca swifterror ptr
 // CHECK:   store ptr null, ptr %swifterror
-// CHECK:   [[RES:%.*]] = call swiftcc { ptr, ptr } @try_apply_helper(ptr %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable({{.*}}) %swifterror)
+// CHECK:   [[RES:%.*]] = call swiftcc { ptr, ptr } @try_apply_helper(ptr %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.*}}) %swifterror)
 // CHECK:   [[RES_0:%.*]] = extractvalue { ptr, ptr } [[RES]], 0
 // CHECK:   [[RES_1:%.*]] = extractvalue { ptr, ptr } [[RES]], 1
 // CHECK:   [[ERRFLAG:%.*]] = load ptr, ptr %swifterror
@@ -209,8 +209,8 @@ bb6:
   return %7 : $()
 }
 
-// CHECK: define{{.*}} internal swiftcc { ptr, ptr } @"$s16try_apply_helperTA"(ptr swiftself %0, ptr noalias nocapture swifterror dereferenceable({{.*}}) %1)
-// CHECK:   tail call swiftcc { ptr, ptr } @try_apply_helper(ptr {{.*}}, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable({{.*}}) %1)
+// CHECK: define{{.*}} internal swiftcc { ptr, ptr } @"$s16try_apply_helperTA"(ptr swiftself %0, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.*}}) %1)
+// CHECK:   tail call swiftcc { ptr, ptr } @try_apply_helper(ptr {{.*}}, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.*}}) %1)
 // CHECK:   ret { ptr, ptr }
 
 sil @partial_apply_test : $@convention(thin) (@owned AnyObject) -> @owned @callee_guaranteed () ->(@owned AnyObject, @error S) {
@@ -234,7 +234,7 @@ entry(%0: $AnyObject):
 // CHECK:entry:
 // CHECK:  %swifterror = alloca swifterror ptr
 // CHECK:  store ptr null, ptr %swifterror
-// CHECK:  call swiftcc { ptr, ptr } %0(ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable({{[0-9]+}}) %swifterror)
+// CHECK:  call swiftcc { ptr, ptr } %0(ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{[0-9]+}}) %swifterror)
 
 sil @apply_closure : $@convention(thin) (@guaranteed @callee_guaranteed () -> (@owned AnyObject, @error S)) -> () {
 entry(%0 : $@callee_guaranteed () ->(@owned AnyObject, @error S)):
@@ -272,7 +272,7 @@ bb6:
   return %t : $()
 }
 
-// CHECK: define{{.*}} swiftcc void @throwNoError(i64 %0, ptr noalias %1, ptr %"\CF\84_0_0", ptr swiftself %2, ptr noalias nocapture swifterror dereferenceable({{.*}}) %3, ptr %4)
+// CHECK: define{{.*}} swiftcc void @throwNoError(i64 %0, ptr noalias %1, ptr %"\CF\84_0_0", ptr swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.*}}) %3, ptr %4)
 // CHECK:  ret void
 
 sil @throwNoError : $@convention(thin) <τ_0_0> (Builtin.Int64, @in τ_0_0) -> @error_indirect τ_0_0 {
@@ -281,14 +281,14 @@ bb0(%0: $*τ_0_0, %1 : $Builtin.Int64, %2 : $*τ_0_0):
   return %5 : $()
 }
 
-// CHECK: define{{.*}} swiftcc void @throwNoErrorGenericOut(ptr noalias sret(%swift.opaque) %0, i64 %1, ptr noalias %2, ptr %"\CF\84_0_0", ptr %"\CF\84_0_1", ptr swiftself %3, ptr noalias nocapture swifterror dereferenceable({{.*}}) %4, ptr %5)
+// CHECK: define{{.*}} swiftcc void @throwNoErrorGenericOut(ptr noalias sret(%swift.opaque) %0, i64 %1, ptr noalias %2, ptr %"\CF\84_0_0", ptr %"\CF\84_0_1", ptr swiftself %3, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.*}}) %4, ptr %5)
 
 sil @throwNoErrorGenericOut : $@convention(thin) <τ_0_0, τ_0_1> (Builtin.Int64, @in τ_0_0) -> (@error_indirect τ_0_0, @out τ_0_1) {
 bb0(%0: $*τ_0_1, %1: $*τ_0_0, %2 : $Builtin.Int64, %3 : $*τ_0_0):
   %5 = tuple ()
   return %5 : $()
 }
-// CHECK: define{{.*}} swiftcc void @throwError(i64 %0, ptr noalias %1, ptr %"\CF\84_0_0", ptr swiftself %2, ptr noalias nocapture swifterror dereferenceable({{.*}}) %3, ptr %4)
+// CHECK: define{{.*}} swiftcc void @throwError(i64 %0, ptr noalias %1, ptr %"\CF\84_0_0", ptr swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable({{.*}}) %3, ptr %4)
 // CHECK: entry:
 // CHECK:  load ptr, ptr
 // CHECK:  [[VW:%.*]] = load ptr, ptr
@@ -309,7 +309,7 @@ sil @throwError2 : $@convention(thin) <T, V> (Builtin.Int64, @in T) -> (@error_i
 // CHECK:   store ptr null, ptr %swifterror
 // CHECK:   [[SIZE:%.*]] = load i64
 // CHECK:   [[TYPEDERR:%.*]] = alloca i8, i64 [[SIZE]]
-// CHECK:   call swiftcc void @throwError2(ptr noalias sret(%swift.opaque) %0, i64 0, ptr noalias %1, ptr %T, ptr %V, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror, ptr [[TYPEDERR]])
+// CHECK:   call swiftcc void @throwError2(ptr noalias sret(%swift.opaque) %0, i64 0, ptr noalias %1, ptr %T, ptr %V, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror, ptr [[TYPEDERR]])
 // CHECK:   [[ERR_FLAG:%.*]] = load ptr, ptr %swifterror
 // CHECK:   [[ISERR:%.*]] = icmp ne ptr [[ERR_FLAG]], null
 // CHECK:   br i1 [[ISERR]]
@@ -379,8 +379,8 @@ bb3:
 
 sil @try_apply_helper_generic : $@convention(thin) <T> (@in T) -> (@out T, @error_indirect T)
 
-// CHECK: define{{.*}} internal swiftcc void @"$s24try_apply_helper_genericTA"(ptr noalias sret(%swift.opaque) %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3)
-// CHECK:   call swiftcc void @try_apply_helper_generic(ptr noalias sret(%swift.opaque) %0, ptr noalias {{%.*}}, ptr %T, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3)
+// CHECK: define{{.*}} internal swiftcc void @"$s24try_apply_helper_genericTA"(ptr noalias sret(%swift.opaque) %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3)
+// CHECK:   call swiftcc void @try_apply_helper_generic(ptr noalias sret(%swift.opaque) %0, ptr noalias {{%.*}}, ptr %T, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3)
 
 sil @partial_apply_test_generic : $@convention(thin) <T> (@in T) -> @owned @callee_guaranteed () ->(@out T, @error_indirect T) {
 entry(%0: $*T):
@@ -403,15 +403,15 @@ entry(%0: $*T):
 // CHECK: define{{.*}} swiftcc void @apply_closure_generic(ptr %0, ptr %1, ptr %T, ptr %V)
 // CHECK:  [[T0:%.*]] = getelementptr inbounds ptr, ptr %T
 // CHECK:  [[T1:%.*]] = load ptr, ptr [[T0]]
-// CHECK:  [[T2:%.*]] = getelementptr inbounds %swift.vwtable{{.*}}
+// CHECK:  [[T2:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable{{.*}}
 // CHECK:  [[T3:%.*]] = load i64, ptr [[T2]]
 // CHECK:  [[T4:%.*]] = alloca i8, i64 [[T3]]
 // CHECK:  [[V0:%.*]] = getelementptr inbounds ptr, ptr %V
 // CHECK:  [[V1:%.*]] = load ptr, ptr [[V0]]
-// CHECK:  [[V2:%.*]] = getelementptr inbounds %swift.vwtable{{.*}}
+// CHECK:  [[V2:%.*]] = getelementptr inbounds{{.*}} %swift.vwtable{{.*}}
 // CHECK:  [[V3:%.*]] = load i64, ptr [[V2]]
 // CHECK:  [[V4:%.*]] = alloca i8, i64 [[V3]]
-// CHECK: call swiftcc void %0(ptr noalias sret(%swift.opaque) [[T4]], ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %swifterror, ptr [[V4]])
+// CHECK: call swiftcc void %0(ptr noalias sret(%swift.opaque) [[T4]], ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror, ptr [[V4]])
 sil @apply_closure_generic : $@convention(thin) <T, V> (@guaranteed @callee_guaranteed () ->(@out T, @error_indirect V)) -> () {
 entry(%0 : $@callee_guaranteed () ->(@out T, @error_indirect V)):
   %err = alloc_stack $V
diff --git a/test/IRGen/typed_throws.swift b/test/IRGen/typed_throws.swift
index d44b65afd2b14..eeb0a3a9d5398 100644
--- a/test/IRGen/typed_throws.swift
+++ b/test/IRGen/typed_throws.swift
@@ -75,7 +75,7 @@ func reabstractAsConcreteThrowing() throws -> Int {
   try passthroughCall(fiveOrTypedBust)
 }
 
-// CHECK-LABEL: define {{.*}} swiftcc void @"$sSi12typed_throws10MyBigErrorOIgdzo_SiACIegrzr_TR"(ptr noalias nocapture sret(%TSi) %0, ptr %1, ptr %2, ptr swiftself %3, ptr noalias nocapture swifterror dereferenceable(8) %4, ptr %5)
+// CHECK-LABEL: define {{.*}} swiftcc void @"$sSi12typed_throws10MyBigErrorOIgdzo_SiACIegrzr_TR"(ptr noalias{{( nocapture)?}} sret(%TSi){{( captures\(none\))?}} %0, ptr %1, ptr %2, ptr swiftself %3, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %4, ptr %5)
 // CHECK: call swiftcc {{i32|i64}} %1
 // CHECK: [[CMP:%.*]] = icmp ne ptr {{%.*}}, null
 // CHECK: br i1 [[CMP]], label %typed.error.load
@@ -107,7 +107,7 @@ func throwsSmallError() throws(SmallError) -> (Float, Int) {
 }
 
 // CHECK: define hidden swiftcc i64 @"$s12typed_throws17catchesSmallErrorSiyF"()
-// CHECK:   [[RES:%.*]] = call swiftcc { float, i64 } @"$s12typed_throws0B10SmallErrorSf_SityAA0cD0VYKF"(ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[RES:%.*]] = call swiftcc { float, i64 } @"$s12typed_throws0B10SmallErrorSf_SityAA0cD0VYKF"(ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[R0:%.*]] = extractvalue { float, i64 } [[RES]], 0
 // CHECK:   [[R1:%.*]] = extractvalue { float, i64 } [[RES]], 1
 // CHECK:   phi i64 [ [[R1]], %typed.error.load ]
@@ -316,9 +316,9 @@ func smallResultLargerError() throws(SmallError) -> Int8? {
 }
 
 // CHECK:  [[COERCED:%.*]] = alloca { i16 }, align 2
-// CHECK:  [[RES:%.*]] = call swiftcc i64 @"$s12typed_throws22smallResultLargerErrors4Int8VSgyAA05SmallF0VYKF"(ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:  [[RES:%.*]] = call swiftcc i64 @"$s12typed_throws22smallResultLargerErrors4Int8VSgyAA05SmallF0VYKF"(ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:  [[TRUNC:%.*]] = trunc i64 [[RES]] to i16
-// CHECK:  [[COERCED_PTR:%.*]] = getelementptr inbounds { i16 }, ptr [[COERCED]], i32 0, i32 0
+// CHECK:  [[COERCED_PTR:%.*]] = getelementptr inbounds{{.*}} { i16 }, ptr [[COERCED]], i32 0, i32 0
 // CHECK:  store i16 [[TRUNC]], ptr [[COERCED_PTR]], align 2
 func callSmallResultLargerError() {
   let res = try! smallResultLargerError()
@@ -335,9 +335,9 @@ func smallErrorLargerResult() throws(UInt8OptSingletonError) -> Int {
 }
 
 // CHECK:  [[COERCED:%.*]] = alloca { i16 }, align 2
-// CHECK:  [[RES:%.*]] = call swiftcc i64 @"$s12typed_throws22smallErrorLargerResultSiyAA017UInt8OptSingletonD0OYKF"(ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:  [[RES:%.*]] = call swiftcc i64 @"$s12typed_throws22smallErrorLargerResultSiyAA017UInt8OptSingletonD0OYKF"(ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:  [[TRUNC:%.*]] = trunc i64 [[RES]] to i16
-// CHECK:  [[COERCED_PTR:%.*]] = getelementptr inbounds { i16 }, ptr [[COERCED]], i32 0, i32 0
+// CHECK:  [[COERCED_PTR:%.*]] = getelementptr inbounds{{.*}} { i16 }, ptr [[COERCED]], i32 0, i32 0
 // CHECK:  store i16 [[TRUNC]], ptr [[COERCED_PTR]], align 2
 func callSmallErrorLargerResult() {
   do {
@@ -359,3 +359,15 @@ struct SomeStruct {
 func someFunc() async throws(SmallError) -> SomeStruct {
     SomeStruct(x: 42, y: 23, z: 25)
 }
+
+// Used to crash the compiler -- https://github.com/swiftlang/swift/issues/80732
+protocol PAssoc<T>: AnyObject {
+    associatedtype T
+    func foo() async throws(SmallError) -> (any PAssoc<T>)
+}
+
+class MyProtocolImpl<T>: PAssoc {
+    func foo() async throws(SmallError) -> (any PAssoc<T>) {
+        fatalError()
+    }
+}
diff --git a/test/IRGen/typed_throws_abi.swift b/test/IRGen/typed_throws_abi.swift
index 6f2479d39c44e..78cad66d967b0 100644
--- a/test/IRGen/typed_throws_abi.swift
+++ b/test/IRGen/typed_throws_abi.swift
@@ -21,7 +21,7 @@ struct ThreeWords: Error {
 }
 
 struct Impl: P {
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2f0yySbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2f0yySbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
     // CHECK:   ret void
@@ -38,7 +38,7 @@ struct Impl: P {
         }
     }
 
-    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi4ImplV2f1ySiSbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi4ImplV2f1ySiSbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
     // CHECK:   ret i64 1
@@ -56,7 +56,7 @@ struct Impl: P {
         return 1
     }
 
-    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2f2ySi_SitSbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2f2ySi_SitSbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
     // CHECK:   ret { i64, i64 } { i64 1, i64 2 }
@@ -74,7 +74,7 @@ struct Impl: P {
         return (1, 2)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2f3ySi_S2itSbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2f3ySi_S2itSbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
     // CHECK:   ret { i64, i64, i64 } { i64 1, i64 2, i64 3 }
@@ -92,7 +92,7 @@ struct Impl: P {
         return (1, 2, 3)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2f4ySi_S3itSbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2f4ySi_S3itSbAA5EmptyVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
     // CHECK:   ret { i64, i64, i64, i64 } { i64 1, i64 2, i64 3, i64 4 }
@@ -110,7 +110,7 @@ struct Impl: P {
         return (1, 2, 3, 4)
     }
 
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2f5ySi_S4itSbAA5EmptyVYKF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2f5ySi_S4itSbAA5EmptyVYKF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4)
     // CHECK:   br i1 %1, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
     // CHECK:   store i64 1, ptr %.elt._value, align 8
@@ -133,7 +133,7 @@ struct Impl: P {
         return (1, 2, 3, 4, 5)
     }
 
-    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi4ImplV2g0yySbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi4ImplV2g0yySbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi7OneWordV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -151,7 +151,7 @@ struct Impl: P {
         }
     }
 
-    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi4ImplV2g1ySiSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi4ImplV2g1ySiSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi7OneWordV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -170,7 +170,7 @@ struct Impl: P {
         return 1
     }
 
-    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2g2ySi_SitSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2g2ySi_SitSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi7OneWordV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -189,7 +189,7 @@ struct Impl: P {
         return (1, 2)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2g3ySi_S2itSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2g3ySi_S2itSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi7OneWordV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -208,7 +208,7 @@ struct Impl: P {
         return (1, 2, 3)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2g4ySi_S3itSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2g4ySi_S3itSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi7OneWordV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -227,7 +227,7 @@ struct Impl: P {
         return (1, 2, 3, 4)
     }
 
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2g5ySi_S4itSbAA7OneWordVYKF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2g5ySi_S4itSbAA7OneWordVYKF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4)
     // CHECK: entry:
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi7OneWordV, align 8
     // CHECK:   br i1 %1, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
@@ -252,7 +252,7 @@ struct Impl: P {
         return (1, 2, 3, 4, 5)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h0yySbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h0yySbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi8TwoWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -270,7 +270,7 @@ struct Impl: P {
         }
     }
 
-    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h1ySiSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h1ySiSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi8TwoWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -289,7 +289,7 @@ struct Impl: P {
         return 1
     }
 
-    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h2ySi_SitSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h2ySi_SitSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi8TwoWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -308,7 +308,7 @@ struct Impl: P {
         return (1, 2)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2h3ySi_S2itSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2h3ySi_S2itSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi8TwoWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -327,7 +327,7 @@ struct Impl: P {
         return (1, 2, 3)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2h4ySi_S3itSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2h4ySi_S3itSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi8TwoWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -346,7 +346,7 @@ struct Impl: P {
         return (1, 2, 3, 4)
     }
 
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2h5ySi_S4itSbAA8TwoWordsVYKF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2h5ySi_S4itSbAA8TwoWordsVYKF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4)
     // CHECK: entry:
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi8TwoWordsV, align 8
     // CHECK:   br i1 %1, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
@@ -371,7 +371,7 @@ struct Impl: P {
         return (1, 2, 3, 4, 5)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i0yySbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i0yySbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi10ThreeWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -389,7 +389,7 @@ struct Impl: P {
         }
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i1ySiSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i1ySiSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi10ThreeWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -408,7 +408,7 @@ struct Impl: P {
         return 1
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i2ySi_SitSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i2ySi_SitSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi10ThreeWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -427,7 +427,7 @@ struct Impl: P {
         return (1, 2)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i3ySi_S2itSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i3ySi_S2itSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi10ThreeWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -446,7 +446,7 @@ struct Impl: P {
         return (1, 2, 3)
     }
 
-    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i4ySi_S3itSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i4ySi_S3itSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi10ThreeWordsV
     // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -465,7 +465,7 @@ struct Impl: P {
         return (1, 2, 3, 4)
     }
 
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2i5ySi_S4itSbAA10ThreeWordsVYKF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi4ImplV2i5ySi_S4itSbAA10ThreeWordsVYKF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4)
     // CHECK: entry:
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi10ThreeWordsV, align 8
     // CHECK:   br i1 %1, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
@@ -494,7 +494,7 @@ struct Impl: P {
 // CHECK: define hidden swiftcc i1 @"$s16typed_throws_abi11callImpl_f0ySbAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2f0yySbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2f0yySbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[ERROR:%.*]] = load ptr, ptr %swifterror, align 8
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
@@ -521,7 +521,7 @@ func callImpl_f0(_ impl: Impl, _ b: Bool) -> Bool {
 // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi11callImpl_f1ySiAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc i64 @"$s16typed_throws_abi4ImplV2f1ySiSbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc i64 @"$s16typed_throws_abi4ImplV2f1ySiSbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[ERROR:%.*]] = load ptr, ptr %swifterror, align 8
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
@@ -548,7 +548,7 @@ func callImpl_f1(_ impl: Impl, _ b: Bool) -> Int {
 // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi11callImpl_f2ySi_SitAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2f2ySi_SitSbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2f2ySi_SitSbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[ERROR:%.*]] = load ptr, ptr %swifterror, align 8
@@ -581,7 +581,7 @@ func callImpl_f2(_ impl: Impl, _ b: Bool) -> (Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi11callImpl_f3ySi_S2itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2f3ySi_S2itSbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2f3ySi_S2itSbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 2
@@ -618,7 +618,7 @@ func callImpl_f3(_ impl: Impl, _ b: Bool) -> (Int, Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi11callImpl_f4ySi_S3itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2f4ySi_S3itSbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2f4ySi_S3itSbAA5EmptyVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 2
@@ -656,12 +656,12 @@ func callImpl_f4(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int) {
     }
 }
 
-// CHECK: define hidden swiftcc void @"$s16typed_throws_abi11callImpl_f5ySi_S4itAA0E0V_SbtF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1)
+// CHECK: define hidden swiftcc void @"$s16typed_throws_abi11callImpl_f5ySi_S4itAA0E0V_SbtF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
 // CHECK:   %swifterror1 = alloca ptr, align 8
 // CHECK:   %call.aggresult = alloca <{ %TSi, %TSi, %TSi, %TSi, %TSi }>, align 8
-// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2f5ySi_S4itSbAA5EmptyVYKF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %call.aggresult, i1 %1, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror, ptr %swifterror1)
+// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2f5ySi_S4itSbAA5EmptyVYKF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %call.aggresult, i1 %1, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror, ptr %swifterror1)
 // CHECK:   [[CALL_RES0:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
 // CHECK:   [[CALL_RES1:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
 // CHECK:   [[CALL_RES2:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
@@ -706,7 +706,7 @@ func callImpl_f5(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int, Int) {
 // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi11callImpl_g0ySiAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc i64 @"$s16typed_throws_abi4ImplV2g0yySbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc i64 @"$s16typed_throws_abi4ImplV2g0yySbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[ERROR:%.*]] = load ptr, ptr %swifterror, align 8
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
@@ -734,7 +734,7 @@ func callImpl_g0(_ impl: Impl, _ b: Bool) -> Int {
 // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi11callImpl_g1ySiAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc i64 @"$s16typed_throws_abi4ImplV2g1ySiSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc i64 @"$s16typed_throws_abi4ImplV2g1ySiSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[ERROR:%.*]] = load ptr, ptr %swifterror, align 8
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
@@ -762,7 +762,7 @@ func callImpl_g1(_ impl: Impl, _ b: Bool) -> Int {
 // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi11callImpl_g2ySi_SitAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2g2ySi_SitSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2g2ySi_SitSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[ERROR:%.*]] = load ptr, ptr %swifterror, align 8
@@ -796,7 +796,7 @@ func callImpl_g2(_ impl: Impl, _ b: Bool) -> (Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi11callImpl_g3ySi_S2itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2g3ySi_S2itSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2g3ySi_S2itSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 2
@@ -834,7 +834,7 @@ func callImpl_g3(_ impl: Impl, _ b: Bool) -> (Int, Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi11callImpl_g4ySi_S3itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2g4ySi_S3itSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2g4ySi_S3itSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 2
@@ -873,12 +873,12 @@ func callImpl_g4(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int) {
     }
 }
 
-// CHECK: define hidden swiftcc void @"$s16typed_throws_abi11callImpl_g5ySi_S4itAA0E0V_SbtF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1)
+// CHECK: define hidden swiftcc void @"$s16typed_throws_abi11callImpl_g5ySi_S4itAA0E0V_SbtF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
 // CHECK:   %swifterror1 = alloca %T16typed_throws_abi7OneWordV, align 8
 // CHECK:   %call.aggresult = alloca <{ %TSi, %TSi, %TSi, %TSi, %TSi }>, align 8
-// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2g5ySi_S4itSbAA7OneWordVYKF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %call.aggresult, i1 %1, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror, ptr %swifterror1)
+// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2g5ySi_S4itSbAA7OneWordVYKF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %call.aggresult, i1 %1, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror, ptr %swifterror1)
 // CHECK:   [[CALL_RES0:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
 // CHECK:   [[CALL_RES1:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
 // CHECK:   [[CALL_RES2:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
@@ -888,8 +888,8 @@ func callImpl_g4(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int) {
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
 // CHECK: typed.error.load:
-// CHECK:   %swifterror1.x = getelementptr inbounds %T16typed_throws_abi7OneWordV, ptr %swifterror1, i32 0, i32 0
-// CHECK:   %swifterror1.x._value = getelementptr inbounds %TSi, ptr %swifterror1.x, i32 0, i32 0
+// CHECK:   %swifterror1.x = getelementptr inbounds{{.*}} %T16typed_throws_abi7OneWordV, ptr %swifterror1, i32 0, i32 0
+// CHECK:   %swifterror1.x._value = getelementptr inbounds{{.*}} %TSi, ptr %swifterror1.x, i32 0, i32 0
 // CHECK:   [[CALL_ERROR_RES:%.*]] = load i64, ptr %swifterror1.x._value, align 8
 // CHECK:   br label %[[SET_ERROR:.*]]
 // CHECK: [[SUCCESS]]:
@@ -927,7 +927,7 @@ func callImpl_g5(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi11callImpl_h0ySi_SitAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h0yySbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h0yySbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[ERROR:%.*]] = load ptr, ptr %swifterror, align 8
@@ -961,7 +961,7 @@ func callImpl_h0(_ impl: Impl, _ b: Bool) -> (Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi11callImpl_h1ySi_SitAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h1ySiSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h1ySiSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[ERROR:%.*]] = load ptr, ptr %swifterror, align 8
@@ -995,7 +995,7 @@ func callImpl_h1(_ impl: Impl, _ b: Bool) -> (Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi11callImpl_h2ySi_SitAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h2ySi_SitSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64 } @"$s16typed_throws_abi4ImplV2h2ySi_SitSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[ERROR:%.*]] = load ptr, ptr %swifterror, align 8
@@ -1030,7 +1030,7 @@ func callImpl_h2(_ impl: Impl, _ b: Bool) -> (Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi11callImpl_h3ySi_S2itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2h3ySi_S2itSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2h3ySi_S2itSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 2
@@ -1069,7 +1069,7 @@ func callImpl_h3(_ impl: Impl, _ b: Bool) -> (Int, Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi11callImpl_h4ySi_S3itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2h4ySi_S3itSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2h4ySi_S3itSbAA8TwoWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 2
@@ -1109,12 +1109,12 @@ func callImpl_h4(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int) {
     }
 }
 
-// CHECK: define hidden swiftcc void @"$s16typed_throws_abi11callImpl_h5ySi_S4itAA0E0V_SbtF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1)
+// CHECK: define hidden swiftcc void @"$s16typed_throws_abi11callImpl_h5ySi_S4itAA0E0V_SbtF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
 // CHECK:   %swifterror1 = alloca %T16typed_throws_abi8TwoWordsV, align 8
 // CHECK:   %call.aggresult = alloca <{ %TSi, %TSi, %TSi, %TSi, %TSi }>, align 8
-// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2h5ySi_S4itSbAA8TwoWordsVYKF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %call.aggresult, i1 %1, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror, ptr %swifterror1)
+// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2h5ySi_S4itSbAA8TwoWordsVYKF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %call.aggresult, i1 %1, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror, ptr %swifterror1)
 // CHECK:   [[CALL_RES0:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
 // CHECK:   [[CALL_RES1:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
 // CHECK:   [[CALL_RES2:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
@@ -1124,8 +1124,8 @@ func callImpl_h4(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int) {
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
 // CHECK: typed.error.load:
-// CHECK:   %swifterror1.x = getelementptr inbounds %T16typed_throws_abi8TwoWordsV, ptr %swifterror1, i32 0, i32 0
-// CHECK:   %swifterror1.x._value = getelementptr inbounds %TSi, ptr %swifterror1.x, i32 0, i32 0
+// CHECK:   %swifterror1.x = getelementptr inbounds{{.*}} %T16typed_throws_abi8TwoWordsV, ptr %swifterror1, i32 0, i32 0
+// CHECK:   %swifterror1.x._value = getelementptr inbounds{{.*}} %TSi, ptr %swifterror1.x, i32 0, i32 0
 // CHECK:   [[CALL_ERROR_RES0:%.*]] = load i64, ptr %swifterror1.x._value, align 8
 // CHECK:   [[CALL_ERROR_RES1:%.*]] = load i64, ptr %swifterror1.y._value, align 8
 // CHECK:   br label %[[SET_ERROR:.*]]
@@ -1165,7 +1165,7 @@ func callImpl_h5(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi11callImpl_i0ySi_S2itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i0yySbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i0yySbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 2
@@ -1203,7 +1203,7 @@ func callImpl_i0(_ impl: Impl, _ b: Bool) -> (Int, Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi11callImpl_i1ySi_S2itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i1ySiSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i1ySiSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 2
@@ -1241,7 +1241,7 @@ func callImpl_i1(_ impl: Impl, _ b: Bool) -> (Int, Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi11callImpl_i2ySi_S2itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i2ySi_SitSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i2ySi_SitSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 2
@@ -1281,7 +1281,7 @@ func callImpl_i2(_ impl: Impl, _ b: Bool) -> (Int, Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi11callImpl_i3ySi_S2itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i3ySi_S2itSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i3ySi_S2itSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64 } [[CALL_RES]], 2
@@ -1321,7 +1321,7 @@ func callImpl_i3(_ impl: Impl, _ b: Bool) -> (Int, Int, Int) {
 // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi11callImpl_i4ySi_S3itAA0E0V_SbtF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i4ySi_S3itSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi4ImplV2i4ySi_S3itSbAA10ThreeWordsVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { i64, i64, i64, i64 } [[CALL_RES]], 2
@@ -1362,12 +1362,12 @@ func callImpl_i4(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int) {
     }
 }
 
-// CHECK: define hidden swiftcc void @"$s16typed_throws_abi11callImpl_i5ySi_S4itAA0E0V_SbtF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1)
+// CHECK: define hidden swiftcc void @"$s16typed_throws_abi11callImpl_i5ySi_S4itAA0E0V_SbtF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
 // CHECK:   %swifterror1 = alloca %T16typed_throws_abi10ThreeWordsV, align 8
 // CHECK:   %call.aggresult = alloca <{ %TSi, %TSi, %TSi, %TSi, %TSi }>, align 8
-// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2i5ySi_S4itSbAA10ThreeWordsVYKF"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %call.aggresult, i1 %1, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror, ptr %swifterror1)
+// CHECK:   call swiftcc void @"$s16typed_throws_abi4ImplV2i5ySi_S4itSbAA10ThreeWordsVYKF"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %call.aggresult, i1 %1, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror, ptr %swifterror1)
 // CHECK:   [[CALL_RES0:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
 // CHECK:   [[CALL_RES1:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
 // CHECK:   [[CALL_RES2:%.*]] = load i64, ptr {{%call.aggresult.*}}, align 8
@@ -1377,8 +1377,8 @@ func callImpl_i4(_ impl: Impl, _ b: Bool) -> (Int, Int, Int, Int) {
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
 // CHECK: typed.error.load:
-// CHECK:   %swifterror1.x = getelementptr inbounds %T16typed_throws_abi10ThreeWordsV, ptr %swifterror1, i32 0, i32 0
-// CHECK:   %swifterror1.x._value = getelementptr inbounds %TSi, ptr %swifterror1.x, i32 0, i32 0
+// CHECK:   %swifterror1.x = getelementptr inbounds{{.*}} %T16typed_throws_abi10ThreeWordsV, ptr %swifterror1, i32 0, i32 0
+// CHECK:   %swifterror1.x._value = getelementptr inbounds{{.*}} %TSi, ptr %swifterror1.x, i32 0, i32 0
 // CHECK:   [[CALL_ERROR_RES0:%.*]] = load i64, ptr %swifterror1.x._value, align 8
 // CHECK:   [[CALL_ERROR_RES1:%.*]] = load i64, ptr %swifterror1.y._value, align 8
 // CHECK:   [[CALL_ERROR_RES2:%.*]] = load i64, ptr %swifterror1.z._value, align 8
@@ -1519,7 +1519,7 @@ struct ImplAsync: PAsync {
         return (1, 2, 3, 4)
     }
 
-    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi9ImplAsyncV2f5ySi_S4itSbYaAA5EmptyVYKF"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2, ptr %3)
+    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi9ImplAsyncV2f5ySi_S4itSbYaAA5EmptyVYKF"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2, ptr %3)
     // CHECK:   [[CORO:%.*]] = call ptr @llvm.coro.begin(token {{%.*}}, ptr null)
     // CHECK:   br i1 %2, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
     // CHECK: [[SUCCESS]]:
@@ -1648,7 +1648,7 @@ struct ImplAsync: PAsync {
         return (1, 2, 3, 4)
     }
 
-    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi9ImplAsyncV2g5ySi_S4itSbYaAA7OneWordVYKF"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2, ptr %3)
+    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi9ImplAsyncV2g5ySi_S4itSbYaAA7OneWordVYKF"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2, ptr %3)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi7OneWordV, align 8
     // CHECK:   [[CORO:%.*]] = call ptr @llvm.coro.begin(token {{%.*}}, ptr null)
     // CHECK:   br i1 %2, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
@@ -1778,7 +1778,7 @@ struct ImplAsync: PAsync {
         return (1, 2, 3, 4)
     }
 
-    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi9ImplAsyncV2h5ySi_S4itSbYaAA8TwoWordsVYKF"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2, ptr %3)
+    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi9ImplAsyncV2h5ySi_S4itSbYaAA8TwoWordsVYKF"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2, ptr %3)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi8TwoWordsV, align 8
     // CHECK:   [[CORO:%.*]] = call ptr @llvm.coro.begin(token {{%.*}}, ptr null)
     // CHECK:   br i1 %2, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
@@ -1908,7 +1908,7 @@ struct ImplAsync: PAsync {
         return (1, 2, 3, 4)
     }
 
-    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi9ImplAsyncV2i5ySi_S4itSbYaAA10ThreeWordsVYKF"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2, ptr %3)
+    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi9ImplAsyncV2i5ySi_S4itSbYaAA10ThreeWordsVYKF"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2, ptr %3)
     // CHECK:   [[ERROR:%.*]] = alloca %T16typed_throws_abi10ThreeWordsV, align 8
     // CHECK:   [[CORO:%.*]] = call ptr @llvm.coro.begin(token {{%.*}}, ptr null)
     // CHECK:   br i1 %2, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
@@ -2127,7 +2127,7 @@ func callImplAsync_f4(_ impl: ImplAsync, _ b: Bool) async -> (Int, Int, Int, Int
     }
 }
 
-// CHECK: define hidden swifttailcc void @"$s16typed_throws_abi16callImplAsync_f5ySi_S4itAA0eF0V_SbtYaF"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2)
+// CHECK: define hidden swifttailcc void @"$s16typed_throws_abi16callImplAsync_f5ySi_S4itAA0eF0V_SbtYaF"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2)
 // CHECK:   %swifterror = alloca ptr, align 8
 // CHECK:   %call.aggresult = alloca <{ %TSi, %TSi, %TSi, %TSi, %TSi }>, align 8
 // CHECK:   %swifterror1 = alloca swifterror ptr, align 8
@@ -2381,7 +2381,7 @@ func callImplAsync_g4(_ impl: ImplAsync, _ b: Bool) async -> (Int, Int, Int, Int
 }
 
 
-// CHECK: define hidden swifttailcc void @"$s16typed_throws_abi16callImplAsync_g5ySi_S4itAA0eF0V_SbtYaF"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2)
+// CHECK: define hidden swifttailcc void @"$s16typed_throws_abi16callImplAsync_g5ySi_S4itAA0eF0V_SbtYaF"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2)
 // CHECK:   %swifterror = alloca %T16typed_throws_abi7OneWordV, align 8
 // CHECK:   %call.aggresult = alloca <{ %TSi, %TSi, %TSi, %TSi, %TSi }>, align 8
 // CHECK:   %swifterror1 = alloca swifterror ptr, align 8
@@ -2401,8 +2401,8 @@ func callImplAsync_g4(_ impl: ImplAsync, _ b: Bool) async -> (Int, Int, Int, Int
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
 // CHECK: typed.error.load:
-// CHECK:   %swifterror.x = getelementptr inbounds %T16typed_throws_abi7OneWordV, ptr %swifterror, i32 0, i32 0
-// CHECK:   %swifterror.x._value = getelementptr inbounds %TSi, ptr %swifterror.x, i32 0, i32 0
+// CHECK:   %swifterror.x = getelementptr inbounds{{.*}} %T16typed_throws_abi7OneWordV, ptr %swifterror, i32 0, i32 0
+// CHECK:   %swifterror.x._value = getelementptr inbounds{{.*}} %TSi, ptr %swifterror.x, i32 0, i32 0
 // CHECK:   [[ERROR_X:%.*]] = load i64, ptr %swifterror.x._value, align 8
 // CHECK:   br label %[[SET_ERROR:.*]]
 // CHECK: [[SUCCESS]]:
@@ -2426,7 +2426,7 @@ func callImplAsync_g4(_ impl: ImplAsync, _ b: Bool) async -> (Int, Int, Int, Int
 // CHECK:   call i1 (ptr, i1, ...) @llvm.coro.end.async(ptr [[CORO]], i1 false, ptr @"{{.*}}", ptr {{%.*}}, ptr {{%.*}})
 // CHECK:   unreachable
 // CHECK: [[SET_ERROR]]:
-// CHECK    [[ERROR_RES0]] = phi i64 [ [[ERROR_X]], %typed.error.load ]
+// CHECK:    [[ERROR_RES0]] = phi i64 [ [[ERROR_X]], %typed.error.load ]
 // CHECK:   store ptr null, ptr %swifterror1, align 8
 // CHECK:   br label %[[COMMON_RET]]
 // CHECK: }
@@ -2647,7 +2647,7 @@ func callImplAsync_h4(_ impl: ImplAsync, _ b: Bool) async -> (Int, Int, Int, Int
 }
 
 
-// CHECK: define hidden swifttailcc void @"$s16typed_throws_abi16callImplAsync_h5ySi_S4itAA0eF0V_SbtYaF"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2)
+// CHECK: define hidden swifttailcc void @"$s16typed_throws_abi16callImplAsync_h5ySi_S4itAA0eF0V_SbtYaF"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2)
 // CHECK:   %swifterror = alloca %T16typed_throws_abi8TwoWordsV, align 8
 // CHECK:   %call.aggresult = alloca <{ %TSi, %TSi, %TSi, %TSi, %TSi }>, align 8
 // CHECK:   %swifterror1 = alloca swifterror ptr, align 8
@@ -2667,8 +2667,8 @@ func callImplAsync_h4(_ impl: ImplAsync, _ b: Bool) async -> (Int, Int, Int, Int
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
 // CHECK: typed.error.load:
-// CHECK:   %swifterror.x = getelementptr inbounds %T16typed_throws_abi8TwoWordsV, ptr %swifterror, i32 0, i32 0
-// CHECK:   %swifterror.x._value = getelementptr inbounds %TSi, ptr %swifterror.x, i32 0, i32 0
+// CHECK:   %swifterror.x = getelementptr inbounds{{.*}} %T16typed_throws_abi8TwoWordsV, ptr %swifterror, i32 0, i32 0
+// CHECK:   %swifterror.x._value = getelementptr inbounds{{.*}} %TSi, ptr %swifterror.x, i32 0, i32 0
 // CHECK:   [[ERROR_X:%.*]] = load i64, ptr %swifterror.x._value, align 8
 // CHECK:   [[ERROR_Y:%.*]] = load i64, ptr %swifterror.y._value, align 8
 // CHECK:   br label %[[SET_ERROR:.*]]
@@ -2927,7 +2927,7 @@ func callImplAsync_i4(_ impl: ImplAsync, _ b: Bool) async -> (Int, Int, Int, Int
 }
 
 
-// CHECK: define hidden swifttailcc void @"$s16typed_throws_abi16callImplAsync_i5ySi_S4itAA0eF0V_SbtYaF"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2)
+// CHECK: define hidden swifttailcc void @"$s16typed_throws_abi16callImplAsync_i5ySi_S4itAA0eF0V_SbtYaF"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2)
 // CHECK:   %swifterror = alloca %T16typed_throws_abi10ThreeWordsV, align 8
 // CHECK:   %call.aggresult = alloca <{ %TSi, %TSi, %TSi, %TSi, %TSi }>, align 8
 // CHECK:   %swifterror1 = alloca swifterror ptr, align 8
@@ -2947,8 +2947,8 @@ func callImplAsync_i4(_ impl: ImplAsync, _ b: Bool) async -> (Int, Int, Int, Int
 // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
 // CHECK:   br i1 [[ISERROR]], label %typed.error.load, label %[[SUCCESS:.*]]
 // CHECK: typed.error.load:
-// CHECK:   %swifterror.x = getelementptr inbounds %T16typed_throws_abi10ThreeWordsV, ptr %swifterror, i32 0, i32 0
-// CHECK:   %swifterror.x._value = getelementptr inbounds %TSi, ptr %swifterror.x, i32 0, i32 0
+// CHECK:   %swifterror.x = getelementptr inbounds{{.*}} %T16typed_throws_abi10ThreeWordsV, ptr %swifterror, i32 0, i32 0
+// CHECK:   %swifterror.x._value = getelementptr inbounds{{.*}} %TSi, ptr %swifterror.x, i32 0, i32 0
 // CHECK:   [[ERROR_X:%.*]] = load i64, ptr %swifterror.x._value, align 8
 // CHECK:   [[ERROR_Y:%.*]] = load i64, ptr %swifterror.y._value, align 8
 // CHECK:   [[ERROR_Z:%.*]] = load i64, ptr %swifterror.z._value, align 8
@@ -2989,7 +2989,7 @@ func callImplAsync_i5(_ impl: ImplAsync, _ b: Bool) async -> (Int, Int, Int, Int
     }
 }
 
-// CHECK: define hidden swiftcc { float, float, i64 } @"$s16typed_throws_abi14nonMatching_f0ySf_SftSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+// CHECK: define hidden swiftcc { float, float, i64 } @"$s16typed_throws_abi14nonMatching_f0ySf_SftSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
 // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
 // CHECK: [[SUCCESS]]:
 // CHECK:   ret { float, float, i64 } { float 1.000000e+00, float 2.000000e+00, i64 undef }
@@ -3009,7 +3009,7 @@ func nonMatching_f0(_ b: Bool) throws(OneWord) -> (Float, Float) {
 // CHECK: define hidden swiftcc { i64, float, float } @"$s16typed_throws_abi18callNonMatching_f0ySi_S2ftSbF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
 // CHECK:   store ptr null, ptr %swifterror, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { float, float, i64 } @"$s16typed_throws_abi14nonMatching_f0ySf_SftSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { float, float, i64 } @"$s16typed_throws_abi14nonMatching_f0ySf_SftSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { float, float, i64 } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { float, float, i64 } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { float, float, i64 } [[CALL_RES]], 2
@@ -3044,7 +3044,7 @@ func callNonMatching_f0(_ b: Bool) -> (Int, Float, Float) {
     }
 }
 
-// define hidden swiftcc { float, i64, float } @"$s16typed_throws_abi14nonMatching_f1ySf_SbSftSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2)
+// define hidden swiftcc { float, i64, float } @"$s16typed_throws_abi14nonMatching_f1ySf_SbSftSbAA7OneWordVYKF"(i1 %0, ptr swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2)
 // CHECK:   br i1 %0, label %[[SUCCESS:.*]], label %[[FAIL:.*]]
 // CHECK: [[SUCCESS]]:
 // CHECK:   ret { float, i64, float } { float 1.000000e+00, i64 1, float 2.000000e+00 }
@@ -3063,7 +3063,7 @@ func nonMatching_f1(_ b: Bool) throws(OneWord) -> (Float, Bool, Float) {
 
 // CHECK: define hidden swiftcc { i64, float, i1, float } @"$s16typed_throws_abi18callNonMatching_f1ySi_SfSbSftSbF"(i1 %0)
 // CHECK:   %swifterror = alloca swifterror ptr, align 8
-// CHECK:   [[CALL_RES:%.*]] = call swiftcc { float, i64, float } @"$s16typed_throws_abi14nonMatching_f1ySf_SbSftSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK:   [[CALL_RES:%.*]] = call swiftcc { float, i64, float } @"$s16typed_throws_abi14nonMatching_f1ySf_SbSftSbAA7OneWordVYKF"(i1 %0, ptr swiftself undef, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %swifterror)
 // CHECK:   [[CALL_RES0:%.*]] = extractvalue { float, i64, float } [[CALL_RES]], 0
 // CHECK:   [[CALL_RES1:%.*]] = extractvalue { float, i64, float } [[CALL_RES]], 1
 // CHECK:   [[CALL_RES2:%.*]] = extractvalue { float, i64, float } [[CALL_RES]], 2
@@ -3225,7 +3225,7 @@ func callNonMatching_f1_async(_ b: Bool) async -> (Int, Float, Bool, Float) {
 }
 
 protocol P {
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2f0yySbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2f0yySbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3236,7 +3236,7 @@ protocol P {
     // CHECK: }
     func f0(_ b: Bool) throws(Empty)
 
-    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi1PP2f1ySiSbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi1PP2f1ySiSbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3247,7 +3247,7 @@ protocol P {
     // CHECK: }
     func f1(_ b: Bool) throws(Empty) -> Int
 
-    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2f2ySi_SitSbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2f2ySi_SitSbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3258,7 +3258,7 @@ protocol P {
     // CHECK: }
     func f2(_ b: Bool) throws(Empty) -> (Int, Int)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2f3ySi_S2itSbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2f3ySi_S2itSbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3269,7 +3269,7 @@ protocol P {
     // CHECK: }
     func f3(_ b: Bool) throws(Empty) -> (Int, Int, Int)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi1PP2f4ySi_S3itSbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi1PP2f4ySi_S3itSbAA5EmptyVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3280,13 +3280,13 @@ protocol P {
     // CHECK: }
     func f4(_ b: Bool) throws(Empty) -> (Int, Int, Int, Int)
 
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2f5ySi_S4itSbAA5EmptyVYKFTj"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
-    // CHECK:   call swiftcc void {{%.*}}(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2f5ySi_S4itSbAA5EmptyVYKFTj"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+    // CHECK:   call swiftcc void {{%.*}}(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
     // CHECK:   ret void
     // CHECK: }
     func f5(_ b: Bool) throws(Empty) -> (Int, Int, Int, Int, Int)
 
-    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi1PP2g0yySbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi1PP2g0yySbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3297,7 +3297,7 @@ protocol P {
     // CHECK: }
     func g0(_ b: Bool) throws(OneWord)
 
-    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi1PP2g1ySiSbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc i64 @"$s16typed_throws_abi1PP2g1ySiSbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3308,7 +3308,7 @@ protocol P {
     // CHECK: }
     func g1(_ b: Bool) throws(OneWord) -> Int
 
-    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2g2ySi_SitSbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2g2ySi_SitSbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3319,7 +3319,7 @@ protocol P {
     // CHECK: }
     func g2(_ b: Bool) throws(OneWord) -> (Int, Int)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2g3ySi_S2itSbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2g3ySi_S2itSbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3330,7 +3330,7 @@ protocol P {
     // CHECK: }
     func g3(_ b: Bool) throws(OneWord) -> (Int, Int, Int)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi1PP2g4ySi_S3itSbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi1PP2g4ySi_S3itSbAA7OneWordVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3341,13 +3341,13 @@ protocol P {
     // CHECK: }
     func g4(_ b: Bool) throws(OneWord) -> (Int, Int, Int, Int)
 
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2g5ySi_S4itSbAA7OneWordVYKFTj"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
-    // CHECK:   call swiftcc void {{%.*}}(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2g5ySi_S4itSbAA7OneWordVYKFTj"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+    // CHECK:   call swiftcc void {{%.*}}(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
     // CHECK:   ret void
     // CHECK: }
     func g5(_ b: Bool) throws(OneWord) -> (Int, Int, Int, Int, Int)
 
-    // CHECK:  define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2h0yySbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK:  define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2h0yySbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3358,7 +3358,7 @@ protocol P {
     // CHECK: }
     func h0(_ b: Bool) throws(TwoWords)
 
-    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2h1ySiSbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2h1ySiSbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3369,7 +3369,7 @@ protocol P {
     // CHECK: }
     func h1(_ b: Bool) throws(TwoWords) -> Int
 
-    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2h2ySi_SitSbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64 } @"$s16typed_throws_abi1PP2h2ySi_SitSbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3380,7 +3380,7 @@ protocol P {
     // CHECK: }
     func h2(_ b: Bool) throws(TwoWords) -> (Int, Int)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2h3ySi_S2itSbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2h3ySi_S2itSbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3391,7 +3391,7 @@ protocol P {
     // CHECK: }
     func h3(_ b: Bool) throws(TwoWords) -> (Int, Int, Int)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi1PP2h4ySi_S3itSbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi1PP2h4ySi_S3itSbAA8TwoWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3402,13 +3402,13 @@ protocol P {
     // CHECK: }
     func h4(_ b: Bool) throws(TwoWords) -> (Int, Int, Int, Int)
 
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2h5ySi_S4itSbAA8TwoWordsVYKFTj"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
-    // CHECK:   call swiftcc void {{%.*}}(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2h5ySi_S4itSbAA8TwoWordsVYKFTj"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+    // CHECK:   call swiftcc void {{%.*}}(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
     // CHECK:   ret void
     // CHECK: }
     func h5(_ b: Bool) throws(TwoWords) -> (Int, Int, Int, Int, Int)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2i0yySbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2i0yySbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3419,7 +3419,7 @@ protocol P {
     // CHECK: }
     func i0(_ b: Bool) throws(ThreeWords)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2i1ySiSbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2i1ySiSbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3430,7 +3430,7 @@ protocol P {
     // CHECK: }
     func i1(_ b: Bool) throws(ThreeWords) -> Int
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2i2ySi_SitSbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2i2ySi_SitSbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3441,7 +3441,7 @@ protocol P {
     // CHECK: }
     func i2(_ b: Bool) throws(ThreeWords) -> (Int, Int)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2i3ySi_S2itSbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64 } @"$s16typed_throws_abi1PP2i3ySi_S2itSbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3452,7 +3452,7 @@ protocol P {
     // CHECK: }
     func i3(_ b: Bool) throws(ThreeWords) -> (Int, Int, Int)
 
-    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi1PP2i4ySi_S3itSbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias nocapture swifterror dereferenceable(8) %2, ptr %3, ptr %4)
+    // CHECK: define hidden swiftcc { i64, i64, i64, i64 } @"$s16typed_throws_abi1PP2i4ySi_S3itSbAA10ThreeWordsVYKFTj"(i1 %0, ptr noalias swiftself %1, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %2, ptr %3, ptr %4)
     // CHECK:   [[ERROR:%.*]] = load ptr, ptr %2
     // CHECK:   [[ISERROR:%.*]] = icmp ne ptr [[ERROR]], null
     // CHECK:   br i1 [[ISERROR]], label %failure, label %success
@@ -3463,8 +3463,8 @@ protocol P {
     // CHECK: }
     func i4(_ b: Bool) throws(ThreeWords) -> (Int, Int, Int, Int)
 
-    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2i5ySi_S4itSbAA10ThreeWordsVYKFTj"(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
-    // CHECK:   call swiftcc void {{%.*}}(ptr noalias nocapture sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>) %0, i1 %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+    // CHECK: define hidden swiftcc void @"$s16typed_throws_abi1PP2i5ySi_S4itSbAA10ThreeWordsVYKFTj"(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+    // CHECK:   call swiftcc void {{%.*}}(ptr noalias{{( nocapture)?}} sret(<{ %TSi, %TSi, %TSi, %TSi, %TSi }>){{( captures\(none\))?}} %0, i1 %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
     // CHECK:   ret void
     // CHECK: }
     func i5(_ b: Bool) throws(ThreeWords) -> (Int, Int, Int, Int, Int)
@@ -3542,7 +3542,7 @@ protocol PAsync {
     // CHECK: }
     func f4(_ b: Bool) async throws(Empty) -> (Int, Int, Int, Int)
 
-    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi6PAsyncP2f5ySi_S4itSbYaAA5EmptyVYKFTj"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2, ptr noalias swiftself %3, ptr %4, ptr %5, ptr %6)
+    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi6PAsyncP2f5ySi_S4itSbYaAA5EmptyVYKFTj"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2, ptr noalias swiftself %3, ptr %4, ptr %5, ptr %6)
     // CHECK:   %swifterror = alloca swifterror ptr
     // CHECK:   [[CORO:%.*]] = call ptr @llvm.coro.begin(token {{%.*}}, ptr null)
     // CHECK:   store ptr null, ptr %swifterror
@@ -3621,7 +3621,7 @@ protocol PAsync {
     // CHECK: }
     func g4(_ b: Bool) async throws(OneWord) -> (Int, Int, Int, Int)
 
-    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi6PAsyncP2g5ySi_S4itSbYaAA7OneWordVYKFTj"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2, ptr noalias swiftself %3, ptr %4, ptr %5, ptr %6)
+    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi6PAsyncP2g5ySi_S4itSbYaAA7OneWordVYKFTj"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2, ptr noalias swiftself %3, ptr %4, ptr %5, ptr %6)
     // CHECK:   %swifterror = alloca swifterror ptr
     // CHECK:   [[CORO:%.*]] = call ptr @llvm.coro.begin(token {{%.*}}, ptr null)
     // CHECK:   store ptr null, ptr %swifterror
@@ -3700,7 +3700,7 @@ protocol PAsync {
     // CHECK: }
     func h4(_ b: Bool) async throws(TwoWords) -> (Int, Int, Int, Int)
 
-    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi6PAsyncP2h5ySi_S4itSbYaAA8TwoWordsVYKFTj"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2, ptr noalias swiftself %3, ptr %4, ptr %5, ptr %6)
+    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi6PAsyncP2h5ySi_S4itSbYaAA8TwoWordsVYKFTj"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2, ptr noalias swiftself %3, ptr %4, ptr %5, ptr %6)
     // CHECK:   %swifterror = alloca swifterror ptr
     // CHECK:   [[CORO:%.*]] = call ptr @llvm.coro.begin(token {{%.*}}, ptr null)
     // CHECK:   store ptr null, ptr %swifterror
@@ -3779,7 +3779,7 @@ protocol PAsync {
     // CHECK: }
     func i4(_ b: Bool) async throws(ThreeWords) -> (Int, Int, Int, Int)
 
-    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi6PAsyncP2i5ySi_S4itSbYaAA10ThreeWordsVYKFTj"(ptr noalias nocapture %0, ptr swiftasync %1, i1 %2, ptr noalias swiftself %3, ptr %4, ptr %5, ptr %6)
+    // CHECK: define hidden swifttailcc void @"$s16typed_throws_abi6PAsyncP2i5ySi_S4itSbYaAA10ThreeWordsVYKFTj"(ptr noalias {{(nocapture|captures\(none\))}} %0, ptr swiftasync %1, i1 %2, ptr noalias swiftself %3, ptr %4, ptr %5, ptr %6)
     // CHECK:   %swifterror = alloca swifterror ptr
     // CHECK:   [[CORO:%.*]] = call ptr @llvm.coro.begin(token {{%.*}}, ptr null)
     // CHECK:   store ptr null, ptr %swifterror
diff --git a/test/IRGen/typed_throws_thunks.swift b/test/IRGen/typed_throws_thunks.swift
index 4535cb4681f80..f9e18188eb087 100644
--- a/test/IRGen/typed_throws_thunks.swift
+++ b/test/IRGen/typed_throws_thunks.swift
@@ -45,9 +45,9 @@ extension P {
     }
   }
 
-  // CHECK-LABEL: define{{.*}} swiftcc void @"$s19typed_throws_thunks1PP2g24bodyyyy7FailureQzYKXE_tAGYKFTj"(ptr %0, ptr %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+  // CHECK-LABEL: define{{.*}} swiftcc void @"$s19typed_throws_thunks1PP2g24bodyyyy7FailureQzYKXE_tAGYKFTj"(ptr %0, ptr %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
 	// CHECK-NOT: ret
-  // CHECK: call swiftcc void {{.*}}(ptr %0, ptr %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
+  // CHECK: call swiftcc void {{.*}}(ptr %0, ptr %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5, ptr %6)
 
   public func g2(body: () throws(Failure) -> Void) throws(Failure) {
     do {
@@ -57,9 +57,9 @@ extension P {
     }
   }
 
-  // CHECK-LABEL: define{{.*}} swiftcc { i64, i64 } @"$s19typed_throws_thunks1PP2g34bodyyyyAA9FixedSizeVYKXE_tAGYKFTj"(ptr %0, ptr %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5)
+  // CHECK-LABEL: define{{.*}} swiftcc { i64, i64 } @"$s19typed_throws_thunks1PP2g34bodyyyyAA9FixedSizeVYKXE_tAGYKFTj"(ptr %0, ptr %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5)
   // CHECK-NOT: ret
-  // CHECK:  call swiftcc { i64, i64 } {{.*}}(ptr %0, ptr %1, ptr noalias swiftself %2, ptr noalias nocapture swifterror dereferenceable(8) %3, ptr %4, ptr %5)
+  // CHECK:  call swiftcc { i64, i64 } {{.*}}(ptr %0, ptr %1, ptr noalias swiftself %2, ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %3, ptr %4, ptr %5)
 
 
   public func g3(body: () throws(FixedSize) -> Void) throws(FixedSize) {
@@ -69,7 +69,7 @@ extension P {
 protocol P2 {
 // CHECK-LABEL: define{{.*}} swiftcc void @"$s19typed_throws_thunks2P2P1fyyAA1EOYKFTj"(
 // CHECK-SAME:      ptr noalias swiftself %0, 
-// CHECK-SAME:      ptr noalias nocapture swifterror dereferenceable(8) %1, 
+// CHECK-SAME:      ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %1, 
 // CHECK-SAME:      ptr %2, ptr %3
 // CHECK-SAME:  )
 // CHECK-SAME:  {
@@ -81,7 +81,7 @@ protocol P2 {
     func f() throws(E)
 // CHECK-LABEL: define{{.*}} swiftcc i8 @"$s19typed_throws_thunks2P2P1gyys4Int8VYKFTj"(
 // CHECk-SAME:      ptr noalias swiftself %0
-// CHECK-SAME:      ptr noalias nocapture swifterror dereferenceable(8) %1
+// CHECK-SAME:      ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %1
 // CHECK-SAME:      ptr %2
 // CHECK-SAME:      ptr %3
 // CHECK-SAME:  )
@@ -93,7 +93,7 @@ protocol P2 {
     func g() throws(Int8)
 // CHECK-LABEL: define{{.*}} swiftcc i8 @"$s19typed_throws_thunks2P2P1hs4Int8VyAA1EOYKFTj"(
 // CHECK-SAME:      ptr noalias swiftself %0
-// CHECK-SAME:      ptr noalias nocapture swifterror dereferenceable(8) %1
+// CHECK-SAME:      ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %1
 // CHECK-SAME:      ptr %2 
 // CHECK-SAME:      ptr %3
 // CHECK-SAME:  )
@@ -105,7 +105,7 @@ protocol P2 {
     func h() throws(E) -> Int8
 // CHECK-LABEL: define{{.*}} swiftcc i8 @"$s19typed_throws_thunks2P2P1is4Int8VyAFYKFTj"(
 // CHECK-SAME:      ptr noalias swiftself %0
-// CHECK-SAME:      ptr noalias nocapture swifterror dereferenceable(8) %1
+// CHECK-SAME:      ptr noalias{{( nocapture)?}} swifterror{{( captures\(none\))?}} dereferenceable(8) %1
 // CHECK-SAME:      ptr %2
 // CHECK-SAME:      ptr %3
 // CHECK-SAME:  )
diff --git a/test/IRGen/typelayout_based_value_operation.sil b/test/IRGen/typelayout_based_value_operation.sil
index d0fbcfa7fc45e..b2083a0fca603 100644
--- a/test/IRGen/typelayout_based_value_operation.sil
+++ b/test/IRGen/typelayout_based_value_operation.sil
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -enable-type-layout %s -emit-ir -sil-verify-all | %FileCheck %s
-// RUNx: %target-swift-frontend -disable-type-layout %s -emit-ir -sil-verify-all | %FileCheck %s --check-prefix=NOTYPELAYOUT
+// RUN: %target-swift-frontend -enable-type-layout %s -Xllvm -sil-disable-pass=mandatory-temp-rvalue-elimination -emit-ir -sil-verify-all | %FileCheck %s
+// RUNx: %target-swift-frontend -disable-type-layout %s -Xllvm -sil-disable-pass=mandatory-temp-rvalue-elimination -emit-ir -sil-verify-all | %FileCheck %s --check-prefix=NOTYPELAYOUT
 
 sil_stage canonical
 import Builtin
diff --git a/test/IRGen/typelayout_based_value_witness.swift b/test/IRGen/typelayout_based_value_witness.swift
index 77ee87f9d965b..2768200d65c50 100644
--- a/test/IRGen/typelayout_based_value_witness.swift
+++ b/test/IRGen/typelayout_based_value_witness.swift
@@ -81,8 +81,8 @@ public enum ForwardEnum<T> {
 // CHECK: }
 
 
-// OPT: define{{.*}} void @"$s30typelayout_based_value_witness1AVwxx"(ptr noalias %object, ptr nocapture readonly %"A<T>")
-// OPT:   [[T_PARAM:%.*]] = getelementptr inbounds i8, ptr %"A<T>", i64 16
+// OPT: define{{.*}} void @"$s30typelayout_based_value_witness1AVwxx"(ptr noalias %object, ptr{{( nocapture)?}} readonly{{( captures\(none\))?}} %"A<T>")
+// OPT:   [[T_PARAM:%.*]] = getelementptr inbounds{{.*}} i8, ptr %"A<T>", i64 16
 // OPT:   [[T:%.*]] = load ptr, ptr [[T_PARAM]]
 // OPT:   [[VWT_ADDR:%.*]] = getelementptr inbounds i8, ptr [[T]], {{(i64|i32)}} -8
 
@@ -94,17 +94,17 @@ public enum ForwardEnum<T> {
 // OPT-ptrauth: [[VWT_INT:%.*]] = tail call i64 @llvm.ptrauth.auth(i64 [[SIGNED_VWT]], i32 2, i64 [[DISCRIMINANT]])
 // OPT-ptrauth: [[VWT:%.*]] = inttoptr i64 [[VWT_INT]] to ptr
 
-// OPT:   [[DESTROY_VW:%.*]] = getelementptr inbounds i8, ptr [[VWT]], {{(i64|i32)}} 8
+// OPT:   [[DESTROY_VW:%.*]] = getelementptr inbounds{{.*}} i8, ptr [[VWT]], {{(i64|i32)}} 8
 // OPT:   [[DESTROY:%.*]] = load ptr, ptr [[DESTROY_VW]]
 
 // OPT-ptrauth: [[DESTROY_ADDR:%.*]] = ptrtoint ptr [[DESTROY_VW]] to i64
 // OPT-ptrauth: [[DISCRIMINANT:%.*]] = tail call i64 @llvm.ptrauth.blend(i64 [[DESTROY_ADDR]], i64 1272)
 
 // OPT:   tail call void [[DESTROY]](ptr noalias %object, ptr [[T]])
-// OPT:   [[SIZE_VW:%.*]] = getelementptr inbounds i8, ptr [[VWT]], {{(i64|i32)}} 64
+// OPT:   [[SIZE_VW:%.*]] = getelementptr inbounds{{.*}} i8, ptr [[VWT]], {{(i64|i32)}} 64
 // OPT:   [[SIZE_T:%.*]] = load {{(i64|i32)}}, ptr [[SIZE_VW]]
 // OPT:   [[OBJECT:%.*]] = ptrtoint ptr %object to {{(i64|i32)}}
-// OPT:   [[FLAGS_VW:%.*]] = getelementptr inbounds i8, ptr [[VWT]], {{(i64|i32)}} 80
+// OPT:   [[FLAGS_VW:%.*]] = getelementptr inbounds{{.*}} i8, ptr [[VWT]], {{(i64|i32)}} 80
 // OPT:   [[FLAGS3:%.*]] = load i32, ptr [[FLAGS_VW]]
 // OPT:   [[FLAGS:%.*]] = and i32 [[FLAGS3]], 255
 // OPT-64:   %flags.alignmentMask = zext nneg i32 [[FLAGS]] to i64
@@ -127,7 +127,7 @@ public enum ForwardEnum<T> {
 // OPT:   ret void
 // CHECK: }
 
-// OPT: define internal void @"$s30typelayout_based_value_witness2E3Owui"(ptr noalias nocapture writeonly %value, i32 %tag, ptr nocapture readonly %"E3<T>")
+// OPT: define internal void @"$s30typelayout_based_value_witness2E3Owui"(ptr noalias{{( nocapture)?}} writeonly{{( captures\(none\))?}} %value, i32 %tag, ptr{{( nocapture)?}} readonly{{( captures\(none\))?}} %"E3<T>")
 // OPT:  [[IS_EMPTY:%.*]] = icmp eq i32 {{%.*}}, 0
 // OPT:  br i1 [[IS_EMPTY]], label %empty-payload, label %non-empty-payload
 // OPT: }
diff --git a/test/IRGen/unconditional_checked_cast.sil b/test/IRGen/unconditional_checked_cast.sil
index adb01d83790f0..5cc204bbde5c2 100644
--- a/test/IRGen/unconditional_checked_cast.sil
+++ b/test/IRGen/unconditional_checked_cast.sil
@@ -10,7 +10,7 @@ sil_vtable C {}
 class D : C {}
 sil_vtable D {}
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @downcast_test(ptr noalias nocapture sret({{.*}}) %0, ptr nocapture dereferenceable({{.*}}) %1) {{.*}} {
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @downcast_test(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr {{(nocapture|captures\(none\))}} dereferenceable({{.*}}) %1) {{.*}} {
 // CHECK: entry:
 // CHECK-NEXT: [[INPUTPTR:%[0-9]+]] = load ptr, ptr [[INPUTPTRPTR:%[0-9]+]], align 8
 // CHECK-NEXT: [[TMP:%.*]] = call swiftcc %swift.metadata_response @"$s26unconditional_checked_cast1DCMa"(i64 0)
diff --git a/test/IRGen/unexploded-calls.swift b/test/IRGen/unexploded-calls.swift
index 3d64fcfbbb19e..661cec671b196 100644
--- a/test/IRGen/unexploded-calls.swift
+++ b/test/IRGen/unexploded-calls.swift
@@ -21,11 +21,11 @@ public func g(_ s : S) {
 // CHECK: entry:
 // CHECK:   alloca
 // CHECK:   [[ALLOCA:%[-._0-9a-zA-Z]+]] = alloca %TSo1SV, align 4
-// CHECK:   [[ALLOCA]].f = getelementptr inbounds %TSo1SV, ptr [[ALLOCA]], i32 0, i32 0
-// CHECK:   [[ALLOCA]].f._value = getelementptr inbounds %TSf, ptr [[ALLOCA]].f, i32 0, i32 0
+// CHECK:   [[ALLOCA]].f = getelementptr inbounds{{.*}} %TSo1SV, ptr [[ALLOCA]], i32 0, i32 0
+// CHECK:   [[ALLOCA]].f._value = getelementptr inbounds{{.*}} %TSf, ptr [[ALLOCA]].f, i32 0, i32 0
 // CHECK:   store float %0, ptr [[ALLOCA]].f._value, align 4
-// CHECK:   [[ALLOCA]].g = getelementptr inbounds %TSo1SV, ptr [[ALLOCA]], i32 0, i32 1
-// CHECK:   [[ALLOCA]].g._value = getelementptr inbounds %TSf, ptr [[ALLOCA]].g, i32 0, i32 0
+// CHECK:   [[ALLOCA]].g = getelementptr inbounds{{.*}} %TSo1SV, ptr [[ALLOCA]], i32 0, i32 1
+// CHECK:   [[ALLOCA]].g._value = getelementptr inbounds{{.*}} %TSf, ptr [[ALLOCA]].g, i32 0, i32 0
 // CHECK:   store float %1, ptr [[ALLOCA]].g._value, align 4
 // CHECK:   %[[LOAD:.*]] = load %struct.S, ptr [[ALLOCA]], align 4
 // CHECK:   call void @f(%struct.S %[[LOAD]])
diff --git a/test/IRGen/unmanaged_objc_throw_func.swift b/test/IRGen/unmanaged_objc_throw_func.swift
index 77114e5b7c234..07f6a7b4d2c01 100644
--- a/test/IRGen/unmanaged_objc_throw_func.swift
+++ b/test/IRGen/unmanaged_objc_throw_func.swift
@@ -16,7 +16,7 @@ import Foundation
     // CHECK: %[[T0:.+]] = call swiftcc { ptr, ptr } @"$ss27_allocateUninitializedArrayySayxG_BptBwlF"(i{{32|64}} 1, ptr @"$sSiN")
     // CHECK-NEXT: %[[T1:.+]] = extractvalue { ptr, ptr } %[[T0]], 0
     // CHECK-NEXT: %[[T2:.+]] = extractvalue { ptr, ptr } %[[T0]], 1
-    // CHECK-NEXT: %._value = getelementptr inbounds %TSi, ptr %[[T2]], i32 0, i32 0
+    // CHECK-NEXT: %._value = getelementptr inbounds{{.*}} %TSi, ptr %[[T2]], i32 0, i32 0
     // CHECK:      %[[T7:.+]] = call swiftcc ptr @"$ss27_finalizeUninitializedArrayySayxGABnlF"(ptr %[[T1]], ptr @"$sSiN")
     // CHECK:      %[[T4:.+]] = call swiftcc ptr @"$sSa10FoundationE19_bridgeToObjectiveCSo7NSArrayCyF"(ptr %[[T7]], ptr @"$sSiN")
     // CHECK-NEXT: store ptr %[[T4]]
diff --git a/test/IRGen/unowned.sil b/test/IRGen/unowned.sil
index f2aadb0505482..3e93db14c3dac 100644
--- a/test/IRGen/unowned.sil
+++ b/test/IRGen/unowned.sil
@@ -49,8 +49,8 @@ bb0(%0 : $@sil_unowned P):
 
 //   initializeBufferWithCopyOfBuffer
 // CHECK:    define internal ptr @"$s7unowned1AVwCP"(ptr noalias [[DESTBUF:%.*]], ptr noalias [[SRCBUF:%.*]], ptr
-// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], ptr [[DESTBUF]], i32 0, i32 0
-// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds [[A]], ptr [[SRCBUF]], i32 0, i32 0
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DESTBUF]], i32 0, i32 0
+// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRCBUF]], i32 0, i32 0
 // CHECK-NEXT: [[T2:%.*]] = load ptr, ptr [[T1]], align 8
 // CHECK-NEXT: call ptr @swift_unownedRetain(ptr returned [[T2]])
 // CHECK-NEXT: store ptr [[T2]], ptr [[T0]], align 8
@@ -58,15 +58,15 @@ bb0(%0 : $@sil_unowned P):
 
 //   destroy
 // CHECK:    define internal void @"$s7unowned1AVwxx"(ptr noalias [[ARG:%.*]], ptr
-// CHECK: [[T1:%.*]] = getelementptr inbounds [[A]], ptr [[ARG]], i32 0, i32 0
+// CHECK: [[T1:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[ARG]], i32 0, i32 0
 // CHECK-NEXT: [[T2:%.*]] = load ptr, ptr [[T1]], align 8
 // CHECK-NEXT: call void @swift_unownedRelease(ptr [[T2]])
 // CHECK-NEXT: ret void
 
 //   initializeWithCopy
 // CHECK:    define internal ptr @"$s7unowned1AVwcp"(ptr noalias [[DEST_OPQ:%.*]], ptr noalias [[SRC_OPQ:%.*]], ptr
-// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
-// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
+// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
 // CHECK-NEXT: [[T2:%.*]] = load ptr, ptr [[T1]], align 8
 // CHECK-NEXT: call ptr @swift_unownedRetain(ptr returned [[T2]])
 // CHECK-NEXT: store ptr [[T2]], ptr [[T0]], align 8
@@ -74,8 +74,8 @@ bb0(%0 : $@sil_unowned P):
 
 //   assignWithCopy
 // CHECK:    define internal ptr @"$s7unowned1AVwca"(ptr [[DEST_OPQ:%.*]], ptr [[SRC_OPQ:%.*]], ptr
-// CHECK: [[DEST_X:%.*]] = getelementptr inbounds [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
-// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
+// CHECK: [[DEST_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
+// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
 // CHECK-NEXT: [[NEW:%.*]] = load ptr, ptr [[SRC_X]], align 8
 // CHECK-NEXT: call ptr @swift_unownedRetain(ptr returned [[NEW]])
 // CHECK-NEXT: [[OLD:%.*]] = load ptr, ptr [[DEST_X]], align 8
@@ -85,8 +85,8 @@ bb0(%0 : $@sil_unowned P):
 
 //   assignWithTake
 // CHECK:    define internal ptr @"$s7unowned1AVwta"(ptr noalias [[DEST_OPQ:%.*]], ptr noalias [[SRC_OPQ:%.*]], ptr
-// CHECK: [[DEST_X:%.*]] = getelementptr inbounds [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
-// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
+// CHECK: [[DEST_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
+// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
 // CHECK-NEXT: [[NEW:%.*]] = load ptr, ptr [[SRC_X]], align 8
 // CHECK-NEXT: [[OLD:%.*]] = load ptr, ptr [[DEST_X]], align 8
 // CHECK-NEXT: store ptr [[NEW]], ptr [[DEST_X]], align 8
diff --git a/test/IRGen/unowned_objc.sil b/test/IRGen/unowned_objc.sil
index 7e1a5a44e3c25..c53688876a383 100644
--- a/test/IRGen/unowned_objc.sil
+++ b/test/IRGen/unowned_objc.sil
@@ -50,18 +50,18 @@ bb0(%p : $P, %q : $P):
   // CHECK-NEXT: llvm.lifetime.start
   %y = alloc_stack $@sil_unowned P
 
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[X]], i32 0, i32 1
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[X]], i32 0, i32 1
   // CHECK-NEXT: store ptr [[PP:%1]], ptr [[T0]], align 8
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[X]], i32 0, i32 0
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[X]], i32 0, i32 0
   // CHECK-NEXT: call ptr @swift_unknownObjectUnownedInit(ptr returned [[T0]], ptr [[PV:%0]])
   store_unowned %p to [init] %x : $*@sil_unowned P
 
   // CHECK-NEXT: call ptr @"$s12unowned_objc1P_pXoWOc"(ptr [[X]], ptr [[Y]])
   copy_addr %x to [init] %y : $*@sil_unowned P
 
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[X]], i32 0, i32 0
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[X]], i32 0, i32 0
   // CHECK-NEXT: [[TV:%.*]] = call ptr @swift_unknownObjectUnownedLoadStrong(ptr [[T0]])
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[X]], i32 0, i32 1
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[X]], i32 0, i32 1
   // CHECK-NEXT: [[TP:%.*]] = load ptr, ptr [[T0]], align 8
   %t0 = load_unowned %x : $*@sil_unowned P
 
@@ -71,9 +71,9 @@ bb0(%p : $P, %q : $P):
   // CHECK-NEXT: call ptr @"$s12unowned_objc1P_pXoWOf"(ptr [[X]], ptr [[Y]])
   copy_addr %x to %y : $*@sil_unowned P
 
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[Y]], i32 0, i32 1
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[Y]], i32 0, i32 1
   // CHECK-NEXT: store ptr [[QP:%3]], ptr [[T0]], align 8
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[Y]], i32 0, i32 0
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[Y]], i32 0, i32 0
   // CHECK-NEXT: call ptr @swift_unknownObjectUnownedAssign(ptr returned [[T0]], ptr [[QV:%2]])
   store_unowned %q to %y : $*@sil_unowned P
 
@@ -83,15 +83,15 @@ bb0(%p : $P, %q : $P):
   // CHECK-NEXT: call ptr @"$s12unowned_objc1P_pXoWOb"(ptr [[Y]], ptr [[X]])
   copy_addr [take] %y to [init] %x : $*@sil_unowned P
 
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[Y]], i32 0, i32 0
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[Y]], i32 0, i32 0
   // CHECK-NEXT: [[TV:%.*]] = call ptr @swift_unknownObjectUnownedTakeStrong(ptr [[T0]])
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[Y]], i32 0, i32 1
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[Y]], i32 0, i32 1
   // CHECK-NEXT: [[TP:%.*]] = load ptr, ptr [[T0]], align 8
   %t1 = load_unowned [take] %y : $*@sil_unowned P
 
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[X]], i32 0, i32 1
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[X]], i32 0, i32 1
   // CHECK-NEXT: store ptr [[TP]], ptr [[T0]], align 8
-  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[UREF]], ptr [[X]], i32 0, i32 0
+  // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} [[UREF]], ptr [[X]], i32 0, i32 0
   // CHECK-NEXT: call ptr @swift_unknownObjectUnownedInit(ptr returned [[T0]], ptr [[TV]])
   store_unowned %t1 to [init] %x : $*@sil_unowned P
 
@@ -121,8 +121,8 @@ bb0(%p : $P, %q : $P):
 
 //   initializeBufferWithCopyOfBuffer
 // CHECK:    define internal ptr @"$s12unowned_objc1AVwCP"(ptr noalias [[DESTBUF:%.*]], ptr noalias [[SRCBUF:%.*]], ptr
-// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], ptr [[DESTBUF]], i32 0, i32 0
-// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds [[A]], ptr [[SRCBUF]], i32 0, i32 0
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DESTBUF]], i32 0, i32 0
+// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRCBUF]], i32 0, i32 0
 // CHECK-NEXT: [[T2:%.*]] = load ptr, ptr [[T1]], align 8
 // CHECK-NEXT: call ptr @swift_unownedRetain(ptr returned [[T2]])
 // CHECK-NEXT: store ptr [[T2]], ptr [[T0]], align 8
@@ -130,15 +130,15 @@ bb0(%p : $P, %q : $P):
 
 //   destroy
 // CHECK:    define internal void @"$s12unowned_objc1AVwxx"(ptr noalias [[ARG:%.*]], ptr
-// CHECK: [[T1:%.*]] = getelementptr inbounds [[A]], ptr [[ARG]], i32 0, i32 0
+// CHECK: [[T1:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[ARG]], i32 0, i32 0
 // CHECK-NEXT: [[T2:%.*]] = load ptr, ptr [[T1]], align 8
 // CHECK-NEXT: call void @swift_unownedRelease(ptr [[T2]])
 // CHECK-NEXT: ret void
 
 //   initializeWithCopy
 // CHECK:    define internal ptr @"$s12unowned_objc1AVwcp"(ptr noalias [[DEST_OPQ:%.*]], ptr noalias [[SRC_OPQ:%.*]], ptr
-// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
-// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
+// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
 // CHECK-NEXT: [[T2:%.*]] = load ptr, ptr [[T1]], align 8
 // CHECK-NEXT: call ptr @swift_unownedRetain(ptr returned [[T2]])
 // CHECK-NEXT: store ptr [[T2]], ptr [[T0]], align 8
@@ -146,8 +146,8 @@ bb0(%p : $P, %q : $P):
 
 //   assignWithCopy
 // CHECK:    define internal ptr @"$s12unowned_objc1AVwca"(ptr [[DEST_OPQ:%.*]], ptr [[SRC_OPQ:%.*]], ptr
-// CHECK: [[DEST_X:%.*]] = getelementptr inbounds [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
-// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
+// CHECK: [[DEST_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
+// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
 // CHECK-NEXT: [[NEW:%.*]] = load ptr, ptr [[SRC_X]], align 8
 // CHECK-NEXT: call ptr @swift_unownedRetain(ptr returned [[NEW]])
 // CHECK-NEXT: [[OLD:%.*]] = load ptr, ptr [[DEST_X]], align 8
@@ -157,8 +157,8 @@ bb0(%p : $P, %q : $P):
 
 //   assignWithTake
 // CHECK:    define internal ptr @"$s12unowned_objc1AVwta"(ptr noalias [[DEST_OPQ:%.*]], ptr noalias [[SRC_OPQ:%.*]], ptr
-// CHECK: [[DEST_X:%.*]] = getelementptr inbounds [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
-// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
+// CHECK: [[DEST_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
+// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
 // CHECK-NEXT: [[NEW:%.*]] = load ptr, ptr [[SRC_X]], align 8
 // CHECK-NEXT: [[OLD:%.*]] = load ptr, ptr [[DEST_X]], align 8
 // CHECK-NEXT: store ptr [[NEW]], ptr [[DEST_X]], align 8
diff --git a/test/IRGen/used.swift b/test/IRGen/used.swift
index 769a16a8f2e99..3b3460910e770 100644
--- a/test/IRGen/used.swift
+++ b/test/IRGen/used.swift
@@ -20,9 +20,9 @@
 // SIL: @_used @_hasStorage @_hasInitialValue var g2: Bool { get set }
 // SIL: @_used func foo()
 
-// SIL: sil_global hidden @$s4used2g0Sivp : $Int
-// SIL: sil_global hidden @$s4used2g1Si_Sitvp : $(Int, Int)
-// SIL: sil_global hidden @$s4used2g2Sbvp : $Bool
+// SIL: sil_global hidden [used] @$s4used2g0Sivp : $Int
+// SIL: sil_global hidden [used] @$s4used2g1Si_Sitvp : $(Int, Int)
+// SIL: sil_global hidden [used] @$s4used2g2Sbvp : $Bool
 
 // SIL: sil hidden [used] @$s4used3fooyyF : $@convention(thin)
 
diff --git a/test/IRGen/variadic_generic_fulfillment.swift b/test/IRGen/variadic_generic_fulfillment.swift
index d3999c000c26d..fab27c03dbe8e 100644
--- a/test/IRGen/variadic_generic_fulfillment.swift
+++ b/test/IRGen/variadic_generic_fulfillment.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-ir %s -target %target-swift-5.9-abi-triple | %FileCheck %s -DINT=i%target-ptrsize
+// RUN: %target-swift-frontend -Xllvm -sil-disable-pass=mandatory-temp-rvalue-elimination -emit-ir %s -target %target-swift-5.9-abi-triple | %FileCheck %s -DINT=i%target-ptrsize
 
 public struct G<T> {}
 
diff --git a/test/IRGen/variadic_generic_fulfillment_tuple.swift b/test/IRGen/variadic_generic_fulfillment_tuple.swift
new file mode 100644
index 0000000000000..7997793b365c0
--- /dev/null
+++ b/test/IRGen/variadic_generic_fulfillment_tuple.swift
@@ -0,0 +1,13 @@
+// RUN: %target-swift-frontend -emit-ir %s -target %target-swift-5.9-abi-triple | %FileCheck %s
+
+struct G<T> {
+  var t: T
+
+  // Make sure we *don't* try to fulfill the pack from the tuple, because we cannot
+  // distinguish the one-element case that way.
+
+  // CHECK-LABEL: define {{.*}} void @"$s34variadic_generic_fulfillment_tuple1GV20fixOuterGenericParamyACyqd__qd__Qp_tGqd__qd__Qp_t_tRvd__qd__qd__Qp_tRszlF"(ptr noalias sret(%swift.opaque) %0, ptr noalias %1, {{i32|i64}} %2, ptr %"each U", ptr noalias swiftself %3)
+  func fixOuterGenericParam<each U>(_ t: T) -> G<T> where T == (repeat each U) {
+    return G<T>(t: t)
+  }
+}
diff --git a/test/IRGen/variadic_generic_functions.sil b/test/IRGen/variadic_generic_functions.sil
index 0d8257698e285..ee6ebc954d411 100644
--- a/test/IRGen/variadic_generic_functions.sil
+++ b/test/IRGen/variadic_generic_functions.sil
@@ -30,9 +30,9 @@ struct Gen2<Fwd : Q> : Q {}
 // CHECK:       entry:
 // CHECK:         [[METADATA_PACK:%[^,]+]] = alloca [1 x ptr]
 // CHECK:         [[WTABLE_PACK:%[^,]+]] = alloca [1 x ptr]
-// CHECK:         [[METADATA_ELEMENT_0:%[^,]+]] = getelementptr inbounds [1 x ptr], ptr [[METADATA_PACK]]
+// CHECK:         [[METADATA_ELEMENT_0:%[^,]+]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[METADATA_PACK]]
 // CHECK:         store ptr {{.*}}$s26variadic_generic_functions3S_2VMf{{.*}}, ptr [[METADATA_ELEMENT_0]]
-// CHECK:         [[WTABLE_ELEMENT_0:%[^,]+]] = getelementptr inbounds [1 x ptr], ptr [[WTABLE_PACK]]
+// CHECK:         [[WTABLE_ELEMENT_0:%[^,]+]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[WTABLE_PACK]]
 // CHECK:         store ptr {{.*}}$s26variadic_generic_functions3S_2VAA1PAAWP{{.*}}, ptr [[WTABLE_ELEMENT_0]]
 // CHECK:         call swiftcc void @g([[INT]] 1, ptr [[METADATA_PACK]], ptr [[WTABLE_PACK]])
 sil @c : $() -> () {
diff --git a/test/IRGen/variadic_generics.sil b/test/IRGen/variadic_generics.sil
index 4876fe99b1d17..5e95b32d9b0d7 100644
--- a/test/IRGen/variadic_generics.sil
+++ b/test/IRGen/variadic_generics.sil
@@ -75,7 +75,7 @@ bb0:
 // CHECK: [[INDEX:%.*]] = add [[INT]] %1, 1
 // CHECK: [[ELT_STORAGE:%.*]] = getelementptr inbounds ptr, ptr %0, [[INT]] [[INDEX]]
 // CHECK: [[ELT_ADDR:%.*]] = load ptr, ptr [[ELT_STORAGE]], align
-// CHECK: [[VALUE_ADDR:%.*]] = getelementptr inbounds %TSi, ptr [[ELT_ADDR]], i32 0, i32 0
+// CHECK: [[VALUE_ADDR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[ELT_ADDR]], i32 0, i32 0
 // CHECK: [[RET:%.*]] = load [[INT]], ptr [[VALUE_ADDR]], align
 // CHECK: ret [[INT]] [[RET]]
 sil @test_pack_element_get_1 : $<each T> (@pack_owned Pack{Int, repeat each T, Int}) -> Int {
@@ -90,7 +90,7 @@ bb0(%pack : $*Pack{Int, repeat each T, Int}):
 // CHECK: [[INDEX:%.*]] = add [[INT]] %2, 1
 // CHECK: [[ELT_STORAGE:%.*]] = getelementptr inbounds ptr, ptr %0, [[INT]] [[INDEX]]
 // CHECK: [[ELT_ADDR:%.*]] = load ptr, ptr [[ELT_STORAGE]], align
-// CHECK: [[VALUE_ADDR:%.*]] = getelementptr inbounds %TSi, ptr [[ELT_ADDR]], i32 0, i32 0
+// CHECK: [[VALUE_ADDR:%.*]] = getelementptr inbounds{{.*}} %TSi, ptr [[ELT_ADDR]], i32 0, i32 0
 // CHECK: store [[INT]] %1, ptr [[VALUE_ADDR]], align
 // CHECK: ret void
 sil @test_pack_element_set_1 : $<each T> (@pack_owned Pack{Int, repeat each T, Int}, Int) -> () {
diff --git a/test/IRGen/weak.sil b/test/IRGen/weak.sil
index 153d6337cc9c1..45a31832a4c41 100644
--- a/test/IRGen/weak.sil
+++ b/test/IRGen/weak.sil
@@ -37,7 +37,7 @@ bb0(%0 : $*A, %1 : $Optional<C>):
   return %4 : $()
 }
 // CHECK:    define{{( dllexport)?}}{{( protected)?}} swiftcc void @test_weak_load_store(ptr dereferenceable({{.*}}) %0, i64 %1) {{.*}} {
-// CHECK:      [[X:%.*]] = getelementptr inbounds [[A:%T4weak1AV]], ptr %0, i32 0, i32 0
+// CHECK:      [[X:%.*]] = getelementptr inbounds{{.*}} [[A:%T4weak1AV]], ptr %0, i32 0, i32 0
 // CHECK-NEXT: [[T0:%.*]] = call ptr @swift_weakLoadStrong(ptr [[X]])
 // CHECK-NEXT: %3 = ptrtoint  ptr %2 to i64
 // CHECK-NEXT: %4 = inttoptr
@@ -60,16 +60,16 @@ bb0(%0 : $*B, %1 : $Optional<P>):
   return %4 : $()
 }
 // CHECK:    define{{( dllexport)?}}{{( protected)?}} swiftcc void @test_weak_load_store_proto(ptr dereferenceable({{.*}}) %0, i64 %1, i64 %2)
-// CHECK:      [[X:%.*]] = getelementptr inbounds [[B:%T4weak1BV]], ptr %0, i32 0, i32 0
-// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds { [[WEAK:%swift.weak]], ptr }, ptr [[X]], i32 0, i32 0
+// CHECK:      [[X:%.*]] = getelementptr inbounds{{.*}} [[B:%T4weak1BV]], ptr %0, i32 0, i32 0
+// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} { [[WEAK:%swift.weak]], ptr }, ptr [[X]], i32 0, i32 0
 // CHECK-NEXT: [[T1:%.*]] = call ptr @swift_unknownObjectWeakLoadStrong(ptr [[T0]])
-// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 1
+// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 1
 // CHECK-NEXT: [[W:%.*]] = load ptr, ptr [[T0]], align 8
 // CHECK: [[TMPOBJ:%.*]] = inttoptr {{.*}} to ptr
 // CHECK: [[TMPTAB:%.*]] = inttoptr {{.*}} to ptr
-// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 1
+// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 1
 // CHECK-NEXT: store ptr [[TMPTAB]], ptr [[T0]], align 8
-// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 0
+// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 0
 // CHECK-NEXT: call ptr @swift_unknownObjectWeakAssign(ptr returned [[T0]], ptr [[TMPOBJ]])
 // CHECK: call void @swift_unknownObjectRelease
 
@@ -86,9 +86,9 @@ bb0(%0 : $Optional<P>):
 // CHECK:      [[X:%.*]] = alloca { [[WEAK]], ptr }, align 8
 // CHECK: [[TMPOBJ:%.*]] = inttoptr {{.*}} to ptr
 // CHECK: [[TMPTAB:%.*]] = inttoptr {{.*}} to ptr
-// CHECK: [[T0:%.*]] = getelementptr inbounds { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 1
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 1
 // CHECK-NEXT: store ptr [[TMPTAB:%.*]], ptr [[T0]], align 8
-// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 0
+// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds{{.*}} { [[WEAK]], ptr }, ptr [[X]], i32 0, i32 0
 // CHECK-NEXT: call ptr @swift_unknownObjectWeakInit(ptr returned [[T0]], ptr [[TMPOBJ:%.*]])
 // CHECK-NEXT: call ptr @"$s4weak1P_pSgXwWOh"(ptr [[X]])
 // CHECK-NEXT: llvm.lifetime.end
@@ -107,7 +107,7 @@ bb0(%0 : $Optional<P>):
 
 //   destroy
 // CHECK:    define internal void @"$s4weak1AVwxx"(ptr noalias [[ARG:%.*]], ptr
-// CHECK: [[T1:%.*]] = getelementptr inbounds [[A]], ptr [[ARG]], i32 0, i32 0
+// CHECK: [[T1:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[ARG]], i32 0, i32 0
 // CHECK-NEXT: call void @swift_weakDestroy(ptr [[T1]])
 // CHECK-NEXT: ret void
 
@@ -116,8 +116,8 @@ bb0(%0 : $Optional<P>):
 
 //   initializeWithCopy
 // CHECK:    define internal ptr @"$s4weak1AVwcp"(ptr noalias [[DEST_OPQ:%.*]], ptr noalias [[SRC_OPQ:%.*]], ptr
-// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
-// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
+// CHECK: [[T0:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
+// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
 // CHECK-NEXT: call ptr @swift_weakCopyInit(ptr returned [[T0]], ptr [[T1]])
 // CHECK-NEXT: ret ptr [[DEST_OPQ]]
 
@@ -126,8 +126,8 @@ bb0(%0 : $Optional<P>):
 
 //   assignWithCopy
 // CHECK:    define internal ptr @"$s4weak1AVwca"(ptr [[DEST_OPQ:%.*]], ptr [[SRC_OPQ:%.*]], ptr
-// CHECK: [[DEST_X:%.*]] = getelementptr inbounds [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
-// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
+// CHECK: [[DEST_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
+// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
 // CHECK-NEXT: call ptr @swift_weakCopyAssign(ptr returned [[DEST_X]], ptr [[SRC_X]])
 // CHECK-NEXT: ret ptr [[DEST_OPQ]]
 
@@ -136,8 +136,8 @@ bb0(%0 : $Optional<P>):
 
 //   assignWithTake
 // CHECK:    define internal ptr @"$s4weak1AVwta"(ptr noalias [[DEST_OPQ:%.*]], ptr noalias [[SRC_OPQ:%.*]], ptr
-// CHECK: [[DEST_X:%.*]] = getelementptr inbounds [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
-// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
+// CHECK: [[DEST_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[DEST_OPQ]], i32 0, i32 0
+// CHECK-NEXT: [[SRC_X:%.*]] = getelementptr inbounds{{.*}} [[A]], ptr [[SRC_OPQ]], i32 0, i32 0
 // CHECK-NEXT: call ptr @swift_weakTakeAssign(ptr returned [[DEST_X]], ptr [[SRC_X]])
 // CHECK-NEXT: ret ptr [[DEST_OPQ]]
 
diff --git a/test/IRGen/weak_class_protocol.sil b/test/IRGen/weak_class_protocol.sil
index b2bd4418c6c3c..9a93d73a4c752 100644
--- a/test/IRGen/weak_class_protocol.sil
+++ b/test/IRGen/weak_class_protocol.sil
@@ -11,9 +11,9 @@ protocol Foo: class { }
 // CHECK-objc:    [[INSTANCE:%.*]] = inttoptr i64 %1 to ptr
 // CHECK-native:  [[INSTANCE:%.*]] = inttoptr i64 %1 to ptr
 // CHECK:         [[WTABLE:%.*]] = inttoptr i64 %2 to ptr
-// CHECK:         [[WTABLE_SLOT:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 1
+// CHECK:         [[WTABLE_SLOT:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 1
 // CHECK:         store ptr [[WTABLE]], ptr [[WTABLE_SLOT]], align 8
-// CHECK:         [[INSTANCE_SLOT:%.*]] = getelementptr inbounds { %swift.weak, ptr }, ptr %0, i32 0, i32 0
+// CHECK:         [[INSTANCE_SLOT:%.*]] = getelementptr inbounds{{.*}} { %swift.weak, ptr }, ptr %0, i32 0, i32 0
 // CHECK-objc:    call ptr @swift_unknownObjectWeakAssign(ptr returned [[INSTANCE_SLOT]], ptr [[INSTANCE]]) {{#[0-9]+}}
 // CHECK-native:  call ptr @swift_weakAssign(ptr returned [[INSTANCE_SLOT]], ptr [[INSTANCE]]) {{#[0-9]+}}
 // CHECK:         ret void
diff --git a/test/IRGen/witness_method.sil b/test/IRGen/witness_method.sil
index 83158ff57addc..f51e83b543eb7 100644
--- a/test/IRGen/witness_method.sil
+++ b/test/IRGen/witness_method.sil
@@ -110,7 +110,7 @@ class TPSReport<CoverSheet> : Strategy {
   func disrupt() -> GrowthHack
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @classArchetypeWitnessMethod(ptr noalias nocapture swiftself dereferenceable({{4|8}}) %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @classArchetypeWitnessMethod(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable({{4|8}}) %0, ptr %Self, ptr %SelfWitnessTable)
 
 sil @classArchetypeWitnessMethod : $@convention(witness_method: Strategy) <T><CoverSheet where T : TPSReport<CoverSheet>> (@in_guaranteed T) -> () {
 entry(%self : $*T):
@@ -118,7 +118,7 @@ entry(%self : $*T):
   return %z : $()
 }
 
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testClassArchetypeWitnessMethod(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture dereferenceable({{4|8}}) %1, ptr %T, ptr %CoverSheet)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @testClassArchetypeWitnessMethod(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable({{4|8}}) %1, ptr %T, ptr %CoverSheet)
 // CHECK: entry:
 // CHECK:  [[WITNESS_FN:%.*]] = load ptr, ptr getelementptr inbounds (ptr, ptr @"$s14witness_method9TPSReportCyxGAA8StrategyAAWP", i32 3)
 // CHECK: call swiftcc void [[WITNESS_FN]](ptr noalias sret({{.*}}) %0, ptr noalias swiftself %1, ptr %T, ptr @"$s14witness_method9TPSReportCyxGAA8StrategyAAWP")
diff --git a/test/IRGen/witness_table_multifile.swift b/test/IRGen/witness_table_multifile.swift
index 3cc30a2a8364c..de4d1defc0fb6 100644
--- a/test/IRGen/witness_table_multifile.swift
+++ b/test/IRGen/witness_table_multifile.swift
@@ -5,7 +5,7 @@
 // CHECK-LABEL: define hidden swiftcc void @"$s23witness_table_multifile3baryyF"
 func bar() {
   // CHECK: call swiftcc void @"$s23witness_table_multifile2goAA1P_pyF"
-  // CHECK:  [[WITNESS_TABLE_ADDR:%[0-9]+]] = getelementptr inbounds [[P_WITNESS_TABLE]], ptr %0, i32 0, i32 2
+  // CHECK:  [[WITNESS_TABLE_ADDR:%[0-9]+]] = getelementptr inbounds{{.*}} [[P_WITNESS_TABLE]], ptr %0, i32 0, i32 2
   // CHECK:  [[WITNESS_TABLE:%[A-Za-z0-9_-]+]] = load ptr, ptr [[WITNESS_TABLE_ADDR]]
   // CHECK:  [[BUFFER:%[0-9]+]] = call ptr @__swift_project_boxed_opaque_existential_1
   // CHECK-NEXT: getelementptr inbounds ptr, ptr [[WITNESS_TABLE]], i32 4
diff --git a/test/IRGen/yield_once.sil b/test/IRGen/yield_once.sil
index 8d9886aa6a51d..cf24aa50f3f07 100644
--- a/test/IRGen/yield_once.sil
+++ b/test/IRGen/yield_once.sil
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-irgen %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth
+// RUN: %target-swift-frontend -emit-irgen -disable-emit-type-malloc-for-coro-frame %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth
 
 import Builtin
 
@@ -51,7 +51,7 @@ sil @test_simple_call : $(Builtin.Int1) -> () {
 entry(%flag : $Builtin.Int1):
   //   Allocate the buffer.
   // CHECK:         [[T0:%.*]] = alloca {{\[}}[[BUFFER_SIZE]] x i8], align [[BUFFER_ALIGN]]
-  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
+  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds{{.*}} {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
   // CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr [[BUFFER]])
 
   //   Prepare the continuation function pointer to block analysis.
@@ -100,7 +100,7 @@ entry:
 
   //   Allocate the buffer.
   // CHECK:         [[T0:%.*]] = alloca {{\[}}[[BUFFER_SIZE]] x i8], align [[BUFFER_ALIGN]]
-  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
+  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds{{.*}} {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
   // CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr [[BUFFER]])
 
   //   Prepare the continuation function pointer to block analysis.
diff --git a/test/IRGen/yield_once_big.sil b/test/IRGen/yield_once_big.sil
index 2d516e42a5eae..b2ec131c165f8 100644
--- a/test/IRGen/yield_once_big.sil
+++ b/test/IRGen/yield_once_big.sil
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-irgen %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth -DINT=i%target-ptrsize
+// RUN: %target-swift-frontend -emit-irgen -disable-emit-type-malloc-for-coro-frame %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth -DINT=i%target-ptrsize
 // UNSUPPORTED: CPU=arm64_32
 
 import Builtin
@@ -57,7 +57,7 @@ entry:
   %1000 = integer_literal $Builtin.Int32, 1000
   apply %marker(%1000) : $@convention(thin) (Builtin.Int32) -> ()
 
-  // CHECK-NEXT:    call swiftcc void @make_big(ptr noalias nocapture sret({{.*}}) [[TEMP]], ptr %C)
+  // CHECK-NEXT:    call swiftcc void @make_big(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[TEMP]], ptr %C)
   %make = function_ref @make_big : $@convention(thin) <T: SomeClass> () -> (@owned Big<T>)
   %value = apply %make<C>() : $@convention(thin) <T: SomeClass> () -> (@owned Big<T>)
 
@@ -97,7 +97,7 @@ sil [ossa] @test_simple_call : $(Builtin.Int1) -> () {
 entry(%flag : $Builtin.Int1):
   //   Allocate the buffer.
   // CHECK:         [[T0:%.*]] = alloca {{\[}}[[BUFFER_SIZE]] x i8], align [[BUFFER_ALIGN]]
-  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
+  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds{{.*}} {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
   // CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr [[BUFFER]])
 
   // CHECK-NEXT:    [[TMP:%.*]] = call swiftcc %swift.metadata_response @"$s14yield_once_big12SomeSubclassCMa"([[INT]] 0)
@@ -113,21 +113,21 @@ entry(%flag : $Builtin.Int1):
   (%value, %token) = begin_apply %0<SomeSubclass>() : $@convention(thin) @yield_once <T: SomeClass> () -> (@yields @owned Big<T>)
 
   //   Load.  This is spurious.
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[BIGSUB:%T14yield_once_big3BigVyAA12SomeSubclassCG]], ptr [[PTR]], i32 0, i32 0
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[BIGSUB:%T14yield_once_big3BigVyAA12SomeSubclassCG]], ptr [[PTR]], i32 0, i32 0
   // CHECK-NEXT:    [[R0:%.*]] = load ptr, ptr [[T0]], align
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[BIGSUB]], ptr [[PTR]], i32 0, i32 1
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[BIGSUB]], ptr [[PTR]], i32 0, i32 1
   // CHECK-NEXT:    [[R1:%.*]] = load ptr, ptr [[T0]], align
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[BIGSUB]], ptr [[PTR]], i32 0, i32 2
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[BIGSUB]], ptr [[PTR]], i32 0, i32 2
   // CHECK-NEXT:    [[R2:%.*]] = load ptr, ptr [[T0]], align
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[BIGSUB]], ptr [[PTR]], i32 0, i32 3
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[BIGSUB]], ptr [[PTR]], i32 0, i32 3
   // CHECK-NEXT:    [[R3:%.*]] = load ptr, ptr [[T0]], align
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[BIGSUB]], ptr [[PTR]], i32 0, i32 4
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[BIGSUB]], ptr [[PTR]], i32 0, i32 4
   // CHECK-NEXT:    [[R4:%.*]] = load ptr, ptr [[T0]], align
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[BIGSUB]], ptr [[PTR]], i32 0, i32 5
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[BIGSUB]], ptr [[PTR]], i32 0, i32 5
   // CHECK-NEXT:    [[R5:%.*]] = load ptr, ptr [[T0]], align
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[BIGSUB]], ptr [[PTR]], i32 0, i32 6
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[BIGSUB]], ptr [[PTR]], i32 0, i32 6
   // CHECK-NEXT:    [[R6:%.*]] = load ptr, ptr [[T0]], align
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[BIGSUB]], ptr [[PTR]], i32 0, i32 7
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[BIGSUB]], ptr [[PTR]], i32 0, i32 7
   // CHECK-NEXT:    [[R7:%.*]] = load ptr, ptr [[T0]], align
 
   //   Branch.
@@ -171,8 +171,8 @@ cont:
 }
 
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc { ptr, ptr } @test_simple_guaranteed
-// CHECK-32-SAME:  (ptr noalias dereferenceable([[BUFFER_SIZE:16]]) %0, ptr noalias nocapture dereferenceable(32) %1, ptr %C)
-// CHECK-64-SAME:  (ptr noalias dereferenceable([[BUFFER_SIZE:32]]) %0, ptr noalias nocapture dereferenceable(64) %1, ptr %C)
+// CHECK-32-SAME:  (ptr noalias dereferenceable([[BUFFER_SIZE:16]]) %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(32) %1, ptr %C)
+// CHECK-64-SAME:  (ptr noalias dereferenceable([[BUFFER_SIZE:32]]) %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(64) %1, ptr %C)
 sil [ossa] @test_simple_guaranteed : $@yield_once <C: SomeClass> (@in_guaranteed BigWrapper<C>) -> (@yields @guaranteed Big<C>) {
 entry(%arg : $*BigWrapper<C>):
   //   Allocate space for the return value of make_big.
diff --git a/test/IRGen/yield_once_biggish.sil b/test/IRGen/yield_once_biggish.sil
index 8efd45f0033d1..56fbaaa0a3460 100644
--- a/test/IRGen/yield_once_biggish.sil
+++ b/test/IRGen/yield_once_biggish.sil
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-irgen %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth -DINT=i%target-ptrsize
+// RUN: %target-swift-frontend -emit-irgen -disable-emit-type-malloc-for-coro-frame %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth -DINT=i%target-ptrsize
 
 // i386 uses a scalar result count of 3 instead of 4, so this test would need
 // to be substantially different to test the functionality there.  It's easier
@@ -59,9 +59,9 @@ entry:
 
   //   Write the spilled objects to the buffer.
   // CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 {{.*}}, ptr [[SPILLS]])
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[SPILLS_T]], ptr [[SPILLS]], i32 0, i32 0
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[SPILLS_T]], ptr [[SPILLS]], i32 0, i32 0
   // CHECK-NEXT:    store ptr [[R2]], ptr [[T0]]
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[SPILLS_T]], ptr [[SPILLS]], i32 0, i32 1
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[SPILLS_T]], ptr [[SPILLS]], i32 0, i32 1
   // CHECK-NEXT:    store ptr [[R3]], ptr [[T0]]
 
   //   Suspend.
@@ -101,7 +101,7 @@ sil [ossa] @test_simple_call : $(Builtin.Int1) -> () {
 entry(%flag : $Builtin.Int1):
   //   Allocate the buffer.
   // CHECK:         [[T0:%.*]] = alloca {{\[}}[[BUFFER_SIZE]] x i8], align [[BUFFER_ALIGN]]
-  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
+  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds{{.*}} {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
   // CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr [[BUFFER]])
 
   // CHECK-NEXT:    [[TMP:%.*]] = call swiftcc %swift.metadata_response @"$s18yield_once_biggish12SomeSubclassCMa"([[INT]] 0)
@@ -115,9 +115,9 @@ entry(%flag : $Builtin.Int1):
   // CHECK-NEXT:    [[R0_ORIG:%.*]] = extractvalue [[RAMP_RESULT_T]] [[RAMP_RESULT]], 1
   // CHECK-NEXT:    [[R1_ORIG:%.*]] = extractvalue [[RAMP_RESULT_T]] [[RAMP_RESULT]], 2
   // CHECK-NEXT:    [[SPILLS:%.*]] = extractvalue [[RAMP_RESULT_T]] [[RAMP_RESULT]], 3
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[SPILLS_T]], ptr [[SPILLS]], i32 0, i32 0
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[SPILLS_T]], ptr [[SPILLS]], i32 0, i32 0
   // CHECK-NEXT:    [[R2_ORIG:%.*]] = load ptr, ptr [[T0]], align
-  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds [[SPILLS_T]], ptr [[SPILLS]], i32 0, i32 1
+  // CHECK-NEXT:    [[T0:%.*]] = getelementptr inbounds{{.*}} [[SPILLS_T]], ptr [[SPILLS]], i32 0, i32 1
   // CHECK-NEXT:    [[R3_ORIG:%.*]] = load ptr, ptr [[T0]], align
   %0 = function_ref @test_simple : $@convention(thin) @yield_once <T: SomeClass> () -> (@yields @owned Biggish<T>)
   (%value, %token) = begin_apply %0<SomeSubclass>() : $@convention(thin) @yield_once <T: SomeClass> () -> (@yields @owned Biggish<T>)
diff --git a/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame.sil b/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame.sil
index 50af74df873ce..9eddb211dd261 100644
--- a/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame.sil
+++ b/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame.sil
@@ -1,4 +1,5 @@
-// RUN: %target-swift-frontend -emit-irgen -enable-emit-type-malloc-for-coro-frame %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth
+// REQUIRES: OS=macosx
+// RUN: %target-swift-frontend -target %target-cpu-apple-macosx15.0 -emit-irgen %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth
 
 import Builtin
 
@@ -10,8 +11,8 @@ sil @marker : $(Builtin.Int32) -> ()
 // CHECK-SAME:  [[CORO_ATTRIBUTES:#[0-9]+]]
 sil @test_simple : $@yield_once () -> () {
 entry:
-  // CHECK-32: [[ID:%.*]] = call token (i32, i32, ptr, ptr, ptr, ptr, ...) @llvm.coro.id.retcon.once(i32 [[BUFFER_SIZE]], i32 [[BUFFER_ALIGN:4]], ptr %0, ptr @"$sIetA_TC", ptr @swift_coroFrameAlloc, ptr @free, i64 38223)
-  // CHECK-64: [[ID:%.*]] = call token (i32, i32, ptr, ptr, ptr, ptr, ...) @llvm.coro.id.retcon.once(i32 [[BUFFER_SIZE]], i32 [[BUFFER_ALIGN:8]], ptr %0, ptr @"$sIetA_TC", ptr @swift_coroFrameAlloc, ptr @free, i64 38223)
+  // CHECK-32: [[ID:%.*]] = call token (i32, i32, ptr, ptr, ptr, ptr, ...) @llvm.coro.id.retcon.once(i32 [[BUFFER_SIZE]], i32 [[BUFFER_ALIGN:4]], ptr %0, ptr @"$sIetA_TC", ptr @__swift_coroFrameAllocStub, ptr @free, i64 38223)
+  // CHECK-64: [[ID:%.*]] = call token (i32, i32, ptr, ptr, ptr, ptr, ...) @llvm.coro.id.retcon.once(i32 [[BUFFER_SIZE]], i32 [[BUFFER_ALIGN:8]], ptr %0, ptr @"$sIetA_TC", ptr @__swift_coroFrameAllocStub, ptr @free, i64 38223)
   // CHECK-NEXT:    [[BEGIN:%.*]] = call ptr @llvm.coro.begin(token [[ID]], ptr null)
 
   // CHECK-NEXT:    call swiftcc void @marker(i32 1000)
@@ -43,6 +44,24 @@ unwind:
   // CHECK-NEXT:    unreachable
 }
 
+// CHECK-32:       declare extern_weak ptr @swift_coroFrameAlloc(i32, i64)
+// CHECK-64:       declare extern_weak ptr @swift_coroFrameAlloc(i64, i64)
+
+// CHECK-32:       define linkonce_odr hidden ptr @__swift_coroFrameAllocStub(i32 %0, i64 %1) #1{{( comdat)?}} {
+// CHECK-64:       define linkonce_odr hidden ptr @__swift_coroFrameAllocStub(i64 %0, i64 %1) #1{{( comdat)?}} {
+// CHECK:       [[T0:%.*]] = icmp ne ptr @swift_coroFrameAlloc, null
+// CHECK:       br i1 [[T0]], label %return-coroFrameAlloc, label %return-malloc
+
+// CHECK-LABEL: return-coroFrameAlloc:
+// CHECK-32:         [[T1:%.*]] = call ptr @swift_coroFrameAlloc(i32 %0, i64 %1)
+// CHECK-64:         [[T1:%.*]] = call ptr @swift_coroFrameAlloc(i64 %0, i64 %1)
+// CHECK:         ret ptr [[T1]]
+
+// CHECK-LABEL: return-malloc:
+// CHECK-32:         [[T2:%.*]] = call ptr @malloc(i32 %0)
+// CHECK-64:         [[T2:%.*]] = call ptr @malloc(i64 %0)
+// CHECK:         ret ptr [[T2]]
+
 // CHECK-LABEL:     declare{{( dllimport)?}}{{( protected)?}} swiftcc void @"$sIetA_TC"
 // CHECK-SAME:      (ptr noalias dereferenceable([[BUFFER_SIZE]]), i1)
 
@@ -51,7 +70,7 @@ sil @test_simple_call : $(Builtin.Int1) -> () {
 entry(%flag : $Builtin.Int1):
   //   Allocate the buffer.
   // CHECK:         [[T0:%.*]] = alloca {{\[}}[[BUFFER_SIZE]] x i8], align [[BUFFER_ALIGN]]
-  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
+  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds{{.*}} {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
   // CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr [[BUFFER]])
 
   //   Prepare the continuation function pointer to block analysis.
@@ -100,7 +119,7 @@ entry:
 
   //   Allocate the buffer.
   // CHECK:         [[T0:%.*]] = alloca {{\[}}[[BUFFER_SIZE]] x i8], align [[BUFFER_ALIGN]]
-  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
+  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds{{.*}} {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
   // CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr [[BUFFER]])
 
   //   Prepare the continuation function pointer to block analysis.
diff --git a/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame_ios.sil b/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame_ios.sil
new file mode 100644
index 0000000000000..05b29b0fed1e1
--- /dev/null
+++ b/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame_ios.sil
@@ -0,0 +1,2 @@
+// REQUIRES: OS=iOS
+// RUN: %target-swift-frontend -target %target-cpu-apple-iphoneos16.0 -emit-irgen %S/yield_once_enable_emit_type_malloc_coro_frame.sil | %FileCheck %S/yield_once_enable_emit_type_malloc_coro_frame.sil --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth
diff --git a/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame_macos_new.sil b/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame_macos_new.sil
new file mode 100644
index 0000000000000..376564aaee80e
--- /dev/null
+++ b/test/IRGen/yield_once_enable_emit_type_malloc_coro_frame_macos_new.sil
@@ -0,0 +1,4 @@
+// REQUIRES: OS=macosx
+// RUN: %target-swift-frontend -target %target-cpu-apple-macosx26.0 -emit-irgen %S/yield_once_enable_emit_type_malloc_coro_frame.sil | %FileCheck %s
+
+// CHECK-NOT: __swift_coroFrameAllocStub
diff --git a/test/IRGen/yield_once_indirect.sil b/test/IRGen/yield_once_indirect.sil
index 331bfe82604fc..f63b810bd71fc 100644
--- a/test/IRGen/yield_once_indirect.sil
+++ b/test/IRGen/yield_once_indirect.sil
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-irgen %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth -DINT=i%target-ptrsize
+// RUN: %target-swift-frontend -emit-irgen -disable-emit-type-malloc-for-coro-frame %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK-%target-ptrsize-%target-ptrauth -DINT=i%target-ptrsize
 
 import Builtin
 import Swift
@@ -42,7 +42,7 @@ entry:
   // CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 {{.*}}, ptr [[TEMP]])
   %temp = alloc_stack $Indirect<C>
 
-  // CHECK-NEXT:    call swiftcc void @make_indirect(ptr noalias nocapture sret({{.*}}) [[TEMP]], ptr %C)
+  // CHECK-NEXT:    call swiftcc void @make_indirect(ptr noalias{{( nocapture)?}} sret({{.*}}){{( captures\(none\))?}} [[TEMP]], ptr %C)
   %make = function_ref @make_indirect : $@convention(thin) <T: SomeClass> () -> (@out Indirect<T>)
   apply %make<C>(%temp) : $@convention(thin) <T: SomeClass> () -> (@out Indirect<T>)
 
@@ -88,7 +88,7 @@ sil @test_simple_call : $(Builtin.Int1) -> () {
 entry(%flag : $Builtin.Int1):
   //   Allocate the buffer.
   // CHECK:         [[T0:%.*]] = alloca {{\[}}[[BUFFER_SIZE]] x i8], align [[BUFFER_ALIGN]]
-  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
+  // CHECK-NEXT:    [[BUFFER:%.*]] = getelementptr inbounds{{.*}} {{\[}}[[BUFFER_SIZE]] x i8], ptr [[T0]], i32 0, i32 0
   // CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 [[BUFFER_SIZE]], ptr [[BUFFER]])
 
   // CHECK-NEXT:    [[TMP:%.*]] = call swiftcc %swift.metadata_response @"$s19yield_once_indirect12SomeSubclassCMa"([[INT]] 0)
diff --git a/test/IRGen/yield_result.sil b/test/IRGen/yield_result.sil
index 30ecd8b2bf47e..b192005c9e7b6 100644
--- a/test/IRGen/yield_result.sil
+++ b/test/IRGen/yield_result.sil
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-irgen %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-cpu --check-prefix=CHECK-%target-ptrsize -DINT=i%target-ptrsize
+// RUN: %target-swift-frontend -emit-irgen -disable-emit-type-malloc-for-coro-frame %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-cpu --check-prefix=CHECK-%target-ptrsize -DINT=i%target-ptrsize
 
 import Builtin
 
@@ -60,7 +60,7 @@ entry:
 
 // CHECK: [[T0:%.*]] = alloca {{\[}}[[BUFFER_SIZE1:.*]] x i8
 // CHECK: [[T1:%.*]] = alloca {{\[}}[[BUFFER_SIZE2:.*]] x i8
-// CHECK: [[BUFFER1:%.*]] = getelementptr inbounds {{\[}}[[BUFFER_SIZE1]] x i8], ptr [[T0]], i32 0, i32 0
+// CHECK: [[BUFFER1:%.*]] = getelementptr inbounds{{.*}} {{\[}}[[BUFFER_SIZE1]] x i8], ptr [[T0]], i32 0, i32 0
 // CHECK: [[CORO1:%.*]] = call ptr @llvm.coro.prepare.retcon(ptr @coro_ret)
 // CHECK: [[FRAME1:%.*]] = call swiftcc { ptr, i64 } [[CORO1]](ptr noalias dereferenceable([[BUFFER_SIZE1]]) [[BUFFER1]]
 // CHECK: [[CONT1:%.*]]  = extractvalue { ptr, i64 } [[FRAME1]], 0
@@ -76,7 +76,7 @@ entry:
   %coro2 = function_ref @coro_ret_pair : $@yield_once @convention(thin) () -> (@yields Builtin.Int64, Builtin.Int64, Builtin.Int64)
   (%second, %token2) = begin_apply %coro2() : $@yield_once @convention(thin) () -> (@yields Builtin.Int64, Builtin.Int64, Builtin.Int64)
 
-// CHECK: [[BUFFER2:%.*]] = getelementptr inbounds {{\[}}[[BUFFER_SIZE2]] x i8], ptr [[T1]], i32 0, i32 0
+// CHECK: [[BUFFER2:%.*]] = getelementptr inbounds{{.*}} {{\[}}[[BUFFER_SIZE2]] x i8], ptr [[T1]], i32 0, i32 0
 // CHECK: [[CORO2:%.*]] = call ptr @llvm.coro.prepare.retcon(ptr @coro_ret_pair)
 // CHECK: [[FRAME2:%.*]] = call swiftcc { ptr, i64 } [[CORO2]](ptr noalias dereferenceable([[BUFFER_SIZE2]]) [[BUFFER2]]
 // CHECK: [[CONT2:%.*]]  = extractvalue { ptr, i64 } [[FRAME2]], 0
@@ -139,7 +139,7 @@ bb0(%0 : $Builtin.Int64):
   %out = alloc_stack $Builtin.Int64
 
   // CHECK: store i64 [[ARG]], ptr [[ARG_COPY]]
-  // CHECK: [[CTX:%.*]] = getelementptr inbounds [[[BUFFER_SIZE]] x i8], ptr [[FRAME]], i32 0, i32 0
+  // CHECK: [[CTX:%.*]] = getelementptr inbounds{{.*}} [[[BUFFER_SIZE]] x i8], ptr [[FRAME]], i32 0, i32 0
   // CHECK: [[CORO:%.*]] = call ptr @llvm.coro.prepare.retcon(ptr @coro_ret_indirect)
   // CHECK: [[FRAME:%.*]] = call swiftcc { ptr, ptr } [[CORO]](ptr{{.*}} [[CTX]], ptr [[INDIRECT_RET]], ptr noalias [[ARG_COPY]], ptr getelementptr inbounds (%swift.full_existential_type, ptr @{{.*}}
 
diff --git a/test/ImportResolution/import-resolution-2.swift b/test/ImportResolution/import-resolution-2.swift
index 370a91a8489de..951a978662f15 100644
--- a/test/ImportResolution/import-resolution-2.swift
+++ b/test/ImportResolution/import-resolution-2.swift
@@ -3,7 +3,7 @@
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/aeiou.swift
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/asdf.swift
 // RUN: %target-swift-frontend -emit-module -o %t -I %t %S/Inputs/letters.swift
-// RUN: %target-swift-frontend -typecheck %s -I %t -sdk "" -verify
+// RUN: %target-swift-frontend -typecheck %s -I %t -sdk "" -verify -verify-ignore-unrelated
 
 import letters
 import aeiou
diff --git a/test/ImportResolution/import-resolution.swift b/test/ImportResolution/import-resolution.swift
index 374a4fbb64dcb..1e9c5e81607e2 100644
--- a/test/ImportResolution/import-resolution.swift
+++ b/test/ImportResolution/import-resolution.swift
@@ -1,13 +1,13 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend -typecheck %s -enable-source-import -I %S/Inputs -sdk "" -verify -show-diagnostics-after-fatal
+// RUN: %target-swift-frontend -typecheck %s -enable-source-import -I %S/Inputs -sdk "" -verify -verify-ignore-unrelated -show-diagnostics-after-fatal
 // RUN: not %target-swift-frontend -typecheck %s -I %S/Inputs -sdk "" -show-diagnostics-after-fatal 2>&1 | %FileCheck %s -check-prefix=CHECK-NO-SOURCE-IMPORT
 
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/abcde.swift
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/aeiou.swift
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/asdf.swift
 // RUN: %target-swift-frontend -emit-module -o %t -I %t %S/Inputs/letters.swift
-// RUN: %target-swift-frontend -typecheck %s -I %t -sdk "" -verify -show-diagnostics-after-fatal
+// RUN: %target-swift-frontend -typecheck %s -I %t -sdk "" -verify -verify-ignore-unrelated -show-diagnostics-after-fatal
 
 // RUN: %target-swift-ide-test -source-filename %s -print-module-imports -module-to-print=letters -I %t | %FileCheck %s -check-prefix=CHECK-IMPORTS
 
diff --git a/test/ImportResolution/import-specific-decl.swift b/test/ImportResolution/import-specific-decl.swift
index a95702d22ef23..29cf7d6e83bf1 100644
--- a/test/ImportResolution/import-specific-decl.swift
+++ b/test/ImportResolution/import-specific-decl.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/asdf.swift
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/abcde.swift
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/aeiou.swift
-// RUN: %target-swift-frontend -typecheck %s -I %t -sdk "" -verify
+// RUN: %target-swift-frontend -typecheck %s -I %t -sdk "" -verify -verify-ignore-unrelated
 // RUN: not %target-swift-frontend -typecheck %s -I %t -sdk "" 2>&1 | %FileCheck %s
 
 import struct aeiou.U
diff --git a/test/ImportResolution/import-specific-fixits.swift b/test/ImportResolution/import-specific-fixits.swift
index a90a45b093606..4589b67959178 100644
--- a/test/ImportResolution/import-specific-fixits.swift
+++ b/test/ImportResolution/import-specific-fixits.swift
@@ -5,7 +5,7 @@
 // RUN: %target-swift-frontend -emit-module -o %t -I %t %S/Inputs/ambiguous.swift
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/DeclsUsedWrongly.swift
 
-// RUN: %target-swift-frontend -typecheck -I %t -serialize-diagnostics-path %t.dia %s -verify
+// RUN: %target-swift-frontend -typecheck -I %t -serialize-diagnostics-path %t.dia %s -verify -verify-ignore-unrelated
 // RUN: c-index-test -read-diagnostics %t.dia > %t.deserialized_diagnostics.txt 2>&1
 // RUN: %FileCheck --input-file=%t.deserialized_diagnostics.txt %s
 
@@ -36,7 +36,7 @@ import struct DeclsUsedWrongly.Choice // expected-error {{'Choice' was imported
 import struct DeclsUsedWrongly.Callback // expected-error {{type alias 'Callback' (aka '() -> ()') cannot be imported as 'struct'}} {{8-14=typealias}}
 import var DeclsUsedWrongly.Callback // expected-error {{'Callback' was imported as 'var', but is a type}} {{8-11=typealias}}
 
-import struct DeclsUsedWrongly.Pair // expected-error {{type alias 'Pair<T>' (aka '(T, T)') cannot be imported as 'struct'}} {{8-14=typealias}}
+import struct DeclsUsedWrongly.Pair // expected-error {{generic type alias 'Pair<T>' (aka '(T, T)') cannot be imported as 'struct'}} {{8-14=typealias}}
 import var DeclsUsedWrongly.Pair // expected-error {{'Pair' was imported as 'var', but is a type}} {{8-11=typealias}}
 
 import struct Swift.print // expected-error {{'print' was imported as 'struct', but is a function}} {{8-14=func}}
@@ -75,4 +75,4 @@ import protocol DeclsUsedWrongly.AnyTopLevelProtocol // expected-error {{type al
 import typealias DeclsUsedWrongly.AnyTopLevelProtocol // no-warning
 import protocol DeclsUsedWrongly.NestedProtocol  // no-warning
 import typealias DeclsUsedWrongly.AnyNestedProtocol // no-warning
-import protocol DeclsUsedWrongly.AnyNestedProtocol // expected-error {{type alias 'AnyNestedProtocol' (aka 'any NamespaceStruct.NestedProtocol') cannot be imported as 'protocol'}} {{8-16=typealias}}
\ No newline at end of file
+import protocol DeclsUsedWrongly.AnyNestedProtocol // expected-error {{type alias 'AnyNestedProtocol' (aka 'any NamespaceStruct.NestedProtocol') cannot be imported as 'protocol'}} {{8-16=typealias}}
diff --git a/test/Index/Store/index_compress.swift b/test/Index/Store/index_compress.swift
new file mode 100644
index 0000000000000..165f3b8e680f5
--- /dev/null
+++ b/test/Index/Store/index_compress.swift
@@ -0,0 +1,11 @@
+// REQUIRES: shell
+
+// RUN: rm -rf %t
+// RUN: %target-swift-frontend -index-store-path %t/idx -index-store-compress -o %t.o -typecheck %s
+// RUN: c-index-test core -print-record %t/idx | %FileCheck %s
+
+// Check that the unit file starts with CIDXR, indicating that the record is indeed compressed.
+// RUN: head -1 %t/idx/**/records/**/*index_compress.swift* | grep '^CIDXR'
+
+func foo() {}
+// CHECK: [[@LINE-1]]:6 | function/Swift | s:4main3fooyyF | Def | rel: 0
diff --git a/test/Index/circular.swift b/test/Index/circular.swift
index 1c819956444be..44d29e5b785dd 100644
--- a/test/Index/circular.swift
+++ b/test/Index/circular.swift
@@ -28,17 +28,17 @@ class Cycle2_C: Cycle2_B {}
 // CHECK:   RelBase | class/Swift | Cycle2_C | {{[^ ]*}}
 
 class TestCase1: XCTestCase {}
-// CHECK: [[@LINE-1]]:7 | class(test)/Swift | TestCase1 | {{[^ ]*}} | Def | rel: 0
+// CHECK: [[@LINE-1]]:7 | class/Swift | TestCase1 | {{[^ ]*}} | Def | rel: 0
 // CHECK: [[@LINE-2]]:18 | class/Swift | XCTestCase | {{[^ ]*}} | Ref,RelBase | rel: 1
-// CHECK:   RelBase | class(test)/Swift | TestCase1 | {{[^ ]*}}
+// CHECK:   RelBase | class/Swift | TestCase1 | {{[^ ]*}}
 class XCTestCase: TestCase1 {}
 // CHECK: [[@LINE-1]]:7 | class/Swift | XCTestCase | {{[^ ]*}} | Def | rel: 0
-// CHECK: [[@LINE-2]]:19 | class(test)/Swift | TestCase1 | {{[^ ]*}} | Ref,RelBase | rel: 1
+// CHECK: [[@LINE-2]]:19 | class/Swift | TestCase1 | {{[^ ]*}} | Ref,RelBase | rel: 1
 // CHECK:   RelBase | class/Swift | XCTestCase | {{[^ ]*}}
 class TestCase2: TestCase1 {}
-// CHECK: [[@LINE-1]]:7 | class(test)/Swift | TestCase2 | {{[^ ]*}} | Def | rel: 0
-// CHECK: [[@LINE-2]]:18 | class(test)/Swift | TestCase1 | {{[^ ]*}} | Ref,RelBase | rel: 1
-// CHECK:   RelBase | class(test)/Swift | TestCase2 | {{[^ ]*}}
+// CHECK: [[@LINE-1]]:7 | class/Swift | TestCase2 | {{[^ ]*}} | Def | rel: 0
+// CHECK: [[@LINE-2]]:18 | class/Swift | TestCase1 | {{[^ ]*}} | Ref,RelBase | rel: 1
+// CHECK:   RelBase | class/Swift | TestCase2 | {{[^ ]*}}
 
 protocol SelfCycleP: SelfCycleP {}
 // CHECK: [[@LINE-1]]:10 | protocol/Swift | SelfCycleP | {{[^ ]*}} | Def | rel: 0
diff --git a/test/Index/conformances.swift b/test/Index/conformances.swift
index b76c102be221f..2aa361659a0da 100644
--- a/test/Index/conformances.swift
+++ b/test/Index/conformances.swift
@@ -10,6 +10,24 @@ struct DirectConf: P1 { // CHECK: [[@LINE]]:8 | struct/Swift | DirectConf | [[Di
     // CHECK-NEXT: RelChild | struct/Swift | DirectConf | [[DirectConf_USR]]
 }
 
+struct LookThroughReprs: (@unchecked (Sendable)) {}
+// CHECK:      [[@LINE-1]]:39 | protocol/Swift | Sendable | s:s8SendableP | Ref,RelBase | rel: 1
+// CHECK-NEXT:   RelBase | struct/Swift | LookThroughReprs | s:14swift_ide_test16LookThroughReprsV
+
+// No RelBase relation here since `Copyable` isn't a base type. Also make sure
+// we don't put a reference at the `~`.
+struct NonCopyable: ~Copyable {}
+// CHECK-NOT: [[@LINE-1]]:21
+// CHECK:     [[@LINE-2]]:22 | protocol/Swift | Copyable | s:s8CopyableP | Ref | rel: 0
+// CHECK-NOT: [[@LINE-3]]:21
+
+protocol NonCopyableProto: ~Copyable {}
+
+struct AlsoNonCopyable: NonCopyableProto & ~Copyable {}
+// CHECK:      [[@LINE-1]]:25 | protocol/Swift | NonCopyableProto | s:14swift_ide_test16NonCopyableProtoP | Ref,RelBase | rel: 1
+// CHECK-NEXT:   RelBase | struct/Swift | AlsoNonCopyable | s:14swift_ide_test15AlsoNonCopyableV
+// CHECK-NEXT: [[@LINE-3]]:45 | protocol/Swift | Copyable | s:s8CopyableP | Ref | rel: 0
+
 struct ConfFromExtension {}
 extension ConfFromExtension: P1 { // CHECK: [[@LINE]]:11 | extension/ext-struct/Swift | ConfFromExtension | [[ConfFromExtension_ext_USR:.*]] | Def
   func foo() {} // CHECK: [[@LINE]]:8 | instance-method/Swift | foo() | [[ConfFromExtension_ext_foo_USR:.*]] | Def,RelChild,RelOver | rel: 2
@@ -81,7 +99,7 @@ class SubMultiConf: BaseMultiConf,P2,P1,P3 { // CHECK: [[@LINE]]:7 | class/Swift
 
 class CompositionType: BaseMultiConf & P1 { // CHECK: [[@LINE]]:7 | class/Swift | CompositionType | [[CompositionType_USR:.*]] | Def
   // CHECK: [[@LINE-1]]:24 | class/Swift | BaseMultiConf | [[BaseMultiConf_USR]] | Ref,RelBase | rel: 1
-  // CHECK: [[@LINE-2]]:24 | protocol/Swift | P1 | [[P1_USR]] | Ref,RelBase | rel: 1
+  // CHECK: [[@LINE-2]]:40 | protocol/Swift | P1 | [[P1_USR]] | Ref,RelBase | rel: 1
   func foo() {}
 }
 
diff --git a/test/Index/index_generic_params.swift b/test/Index/index_generic_params.swift
index f7ef24acd39ec..0fbb6b4bcc695 100644
--- a/test/Index/index_generic_params.swift
+++ b/test/Index/index_generic_params.swift
@@ -165,3 +165,16 @@ _ = C.Nested(value: 1)
 // CHECK-NEXT: [[@LINE+2]]:7 | struct/Swift | Nested | [[C_Nested_USR]] | Ref | rel: 0
 // CHECK-NEXT: [[@LINE+1]]:14 | constructor/Swift | init(value:) | [[C_Nested_init_USR]] | Ref,Call | rel: 0
 _ = C.Nested.init(value: 1)
+
+// MARK: - Test value generic parameters
+
+struct HasValueGenericParam<let Param: Int> {
+// CHECK:      [[@LINE-1]]:33 | type-alias/generic-type-param/Swift | Param | s:14swift_ide_test20HasValueGenericParamV0G0xmfp | Def,RelChild | rel: 1
+// CHECK-NEXT:   RelChild | struct/Swift | HasValueGenericParam
+  func foo() {
+    _ = Param
+    // CHECK:      [[@LINE-1]]:9 | type-alias/generic-type-param/Swift | Param | s:14swift_ide_test20HasValueGenericParamV0G0xmfp | Ref,RelCont | rel: 1
+    // CHECK-NEXT:   RelCont | instance-method/Swift | foo()
+  }
+}
+
diff --git a/test/Index/index_imported.swift b/test/Index/index_imported.swift
new file mode 100644
index 0000000000000..6402a8a2e18bf
--- /dev/null
+++ b/test/Index/index_imported.swift
@@ -0,0 +1,43 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file --leading-lines %s %t
+
+// RUN: %target-swift-frontend -emit-module -o %t/Lib.swiftmodule %t/Lib.swift -module-name Lib
+// RUN: %target-swift-ide-test -print-indexed-symbols -source-filename %t/main.swift -module-to-print Lib -I %t | %FileCheck %s --check-prefix LIB
+// RUN: %target-swift-ide-test -print-indexed-symbols -source-filename %t/main.swift -I %t | %FileCheck %s
+
+//--- Lib.swift
+
+public protocol P {}
+public protocol Q {}
+public protocol R {}
+
+public typealias X = Q & R
+
+public struct S: X & P {}
+// LIB:      0:0 | protocol/Swift | Q | s:3Lib1QP | Ref,RelBase | rel: 1
+// LIB-NEXT:   RelBase | struct/Swift | S | s:3Lib1SV
+// LIB-NEXT: 0:0 | protocol/Swift | R | s:3Lib1RP | Ref,RelBase | rel: 1
+// LIB-NEXT:   RelBase | struct/Swift | S | s:3Lib1SV
+// LIB-NEXT: 0:0 | protocol/Swift | P | s:3Lib1PP | Ref,RelBase | rel: 1
+// LIB-NEXT:   RelBase | struct/Swift | S | s:3Lib1SV
+
+public protocol NonCopyableProto: ~Copyable {}
+public struct NonCopyable: NonCopyableProto & ~Copyable {}
+// LIB:      0:0 | protocol/Swift | NonCopyableProto | s:3Lib16NonCopyableProtoP | Ref,RelBase | rel: 1
+// LIB-NEXT:   RelBase | struct/Swift | NonCopyable | s:3Lib11NonCopyableV
+
+// We don't currently have a relation for Copyable.
+// LIB-NOT: s:s8CopyableP
+
+//--- main.swift
+
+import Lib
+
+struct K: P & X {}
+// CHECK:      [[@LINE-1]]:11 | protocol/Swift | P | s:3Lib1PP | Ref,RelBase | rel: 1
+// CHECK-NEXT:   RelBase | struct/Swift | K | s:14swift_ide_test1KV
+// CHECK-NEXT: [[@LINE-3]]:15 | type-alias/Swift | X | s:3Lib1Xa | Ref | rel: 0
+// CHECK-NEXT: [[@LINE-4]]:15 | protocol/Swift | Q | s:3Lib1QP | Ref,Impl,RelBase | rel: 1
+// CHECK-NEXT:   RelBase | struct/Swift | K | s:14swift_ide_test1KV
+// CHECK-NEXT: [[@LINE-6]]:15 | protocol/Swift | R | s:3Lib1RP | Ref,Impl,RelBase | rel: 1
+// CHECK-NEXT:   RelBase | struct/Swift | K | s:14swift_ide_test1KV
diff --git a/test/Inputs/clang-importer-sdk/swift-modules/CoreFoundation.swift b/test/Inputs/clang-importer-sdk/swift-modules/CoreFoundation.swift
index bfe37b338a67e..bf7afc327b6ff 100644
--- a/test/Inputs/clang-importer-sdk/swift-modules/CoreFoundation.swift
+++ b/test/Inputs/clang-importer-sdk/swift-modules/CoreFoundation.swift
@@ -3,7 +3,7 @@
 protocol _CFObject: Hashable {}
 
 #if CGFLOAT_IN_COREFOUNDATION
-public struct CGFloat {
+public struct CGFloat: @unchecked Sendable {
 #if _pointerBitWidth(_32)
   public typealias UnderlyingType = Float
 #elseif _pointerBitWidth(_64)
diff --git a/test/Inputs/clang-importer-sdk/swift-modules/CoreGraphics.swift b/test/Inputs/clang-importer-sdk/swift-modules/CoreGraphics.swift
index 1ff7f9a4c0d95..0b9b5fd02982f 100644
--- a/test/Inputs/clang-importer-sdk/swift-modules/CoreGraphics.swift
+++ b/test/Inputs/clang-importer-sdk/swift-modules/CoreGraphics.swift
@@ -6,7 +6,7 @@ public func == (lhs: CGPoint, rhs: CGPoint) -> Bool {
 }
 
 #if !CGFLOAT_IN_COREFOUNDATION
-public struct CGFloat {
+public struct CGFloat: Sendable {
 #if _pointerBitWidth(_32)
   public typealias UnderlyingType = Float
 #elseif _pointerBitWidth(_64)
diff --git a/test/Inputs/clang-importer-sdk/usr/include/Foundation.h b/test/Inputs/clang-importer-sdk/usr/include/Foundation.h
index 60998cffdaaa5..03e3240480fb3 100644
--- a/test/Inputs/clang-importer-sdk/usr/include/Foundation.h
+++ b/test/Inputs/clang-importer-sdk/usr/include/Foundation.h
@@ -1243,3 +1243,11 @@ void takeNullableId(_Nullable id);
 @interface PaletteDescriptor : NSObject <NSCopying>
 @property (readonly, nonnull) ColorArray *colors;
 @end
+
+@protocol NSIndexable <NSObject>
+- (id)objectAtIndex:(NSInteger)index;
+@end
+
+@interface NSCouldConformToIndexable : NSObject
+- (id)objectAtIndex:(NSInteger)index;
+@end
diff --git a/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h b/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h
index 15d4468ff8ce4..4b9f851e8785a 100644
--- a/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h
+++ b/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h
@@ -11,6 +11,7 @@
   #define NONSENDABLE __attribute__((__swift_attr__("@_nonSendable")))
   #define ASSUME_NONSENDABLE_BEGIN _Pragma("clang attribute ASSUME_NONSENDABLE.push (__attribute__((swift_attr(\"@_nonSendable(_assumed)\"))), apply_to = any(objc_interface, record, enum))")
   #define ASSUME_NONSENDABLE_END _Pragma("clang attribute ASSUME_NONSENDABLE.pop")
+  #define ASYNC_NAME(NAME) __attribute__((swift_async_name(#NAME)))
 #else
   // If we take this #else, we should see minor failures of some subtests,
   // but not systematic failures of everything that uses this header.
@@ -18,6 +19,7 @@
   #define NONSENDABLE
   #define ASSUME_NONSENDABLE_BEGIN
   #define ASSUME_NONSENDABLE_END
+  #define ASYNC_NAME(NAME)
 #endif
 
 #define NS_ENUM(_type, _name) enum _name : _type _name; \
@@ -123,6 +125,19 @@ typedef void (^NonsendableCompletionHandler)(NSString * _Nullable, NSString * _N
     __attribute__((swift_async_error(zero_argument, 3)));
 - (void)getIceCreamFlavorWithCompletionHandler:
     (void (^)(Flavor flavor, NSError *__nullable error))completionHandler;
+
+@property(class, strong, readonly) SlowServer *standardServer;
+- (void)getValueWithKey:(NSString *)valueIdentifier
+             completion:(void (^)(NSString *__nullable value,
+                                  NSError *__nullable error))completionHandler;
+- (void)getMainActorValueWithKey:(NSString *)valueIdentifier
+                      completion:
+                          (void (^)(NSString *__nullable value,
+                                    NSError *__nullable error))completionHandler
+    MAIN_ACTOR;
+
+- (void)startAt:(__nullable NSDate *)value
+     completion:(void (^_Nonnull)(void))completion;
 @end
 
 @protocol RefrigeratorDelegate<NSObject>
@@ -250,7 +265,7 @@ typedef NS_ERROR_ENUM(unsigned, SendableErrorCode, SendableErrorDomain) {
 typedef NS_ERROR_ENUM(unsigned, NonSendableErrorCode, NonSendableErrorDomain) {
   NonSendableErrorCodeFoo, NonSendableErrorCodeBar
 } NONSENDABLE;
-// expected-warning@-3 {{cannot make error code type 'NonSendableErrorCode' non-sendable because Swift errors are always sendable}}
+// expected-warning@-3 {{cannot make error code type 'NonSendableErrorCode' non-Sendable because Swift errors are always sendable}}
 
 UI_ACTOR
 @interface PictureFrame : NSObject
@@ -368,4 +383,13 @@ MAIN_ACTOR
 - (void)loadFloatOrThrowWithCompletionHandler:(void (^)(float, NSError* __nullable)) completionHandler;
 @end
 
+NONSENDABLE
+@interface ImportObjCAsyncGetter : NSObject
+
+- (void)getSendableClassesWithCompletionHandler:
+    (void (^SENDABLE)(NSArray<SendableClass *> *myClasses))handler
+    ASYNC_NAME(getter:sendableClasses());
+
+@end
+
 #pragma clang assume_nonnull end
diff --git a/test/Inputs/clang-importer-sdk/usr/include/imported_macro_error.h b/test/Inputs/clang-importer-sdk/usr/include/imported_macro_error.h
new file mode 100644
index 0000000000000..3498d99cbbd51
--- /dev/null
+++ b/test/Inputs/clang-importer-sdk/usr/include/imported_macro_error.h
@@ -0,0 +1,7 @@
+#if __SWIFT_ATTR_SUPPORTS_MACROS
+#define ERROR_MACRO __attribute__((swift_attr("@macro_library.ExpandTypeError")))
+#else
+#define ERROR_MACRO
+#endif
+
+void foo() ERROR_MACRO;
diff --git a/test/Inputs/clang-importer-sdk/usr/include/module.modulemap b/test/Inputs/clang-importer-sdk/usr/include/module.modulemap
index c396aac08d3d2..750a21baab1a6 100644
--- a/test/Inputs/clang-importer-sdk/usr/include/module.modulemap
+++ b/test/Inputs/clang-importer-sdk/usr/include/module.modulemap
@@ -156,4 +156,8 @@ module IncompleteTypes {
 
 module CompletionHandlerGlobals {
   header "completion_handler_globals.h"
-}
\ No newline at end of file
+}
+
+module ImportedMacroError {
+  header "imported_macro_error.h"
+}
diff --git a/test/Inputs/clang-importer-sdk/usr/include/objc/objc.h b/test/Inputs/clang-importer-sdk/usr/include/objc/objc.h
index fb6aea4e73ff0..18441bfdfae89 100644
--- a/test/Inputs/clang-importer-sdk/usr/include/objc/objc.h
+++ b/test/Inputs/clang-importer-sdk/usr/include/objc/objc.h
@@ -13,6 +13,8 @@ typedef int NSInteger;
 #endif
 
 typedef __typeof__(__objc_yes) BOOL;
+#define YES __objc_yes
+#define NO  __objc_no
 
 typedef struct objc_selector    *SEL;
 SEL sel_registerName(const char *str);
diff --git a/test/Inputs/conditional_conformance_basic_conformances.swift b/test/Inputs/conditional_conformance_basic_conformances.swift
index 40e8cc66b3c40..978a47239db20 100644
--- a/test/Inputs/conditional_conformance_basic_conformances.swift
+++ b/test/Inputs/conditional_conformance_basic_conformances.swift
@@ -18,7 +18,7 @@ extension Single: P1 where A: P2 {
 
 // witness method for Single.normal
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6SingleVyxGAA2P1A2A2P2RzlAaEP6normalyyFTW"(ptr noalias nocapture swiftself %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6SingleVyxGAA2P1A2A2P2RzlAaEP6normalyyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[A_P2_i8star:%.*]] = load ptr, ptr [[A_P2_PTR]], align 8
@@ -30,7 +30,7 @@ extension Single: P1 where A: P2 {
 
 // witness method for Single.generic
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6SingleVyxGAA2P1A2A2P2RzlAaEP7genericyyqd__AA2P3Rd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias nocapture swiftself %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6SingleVyxGAA2P1A2A2P2RzlAaEP7genericyyqd__AA2P3Rd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %1, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[A_P2_i8star:%.*]] = load ptr, ptr [[A_P2_PTR]], align 8
@@ -48,7 +48,7 @@ public func single_generic<T: P2>(_: T.Type) {
 // CHECK:         %conditional.requirement.buffer = alloca [1 x ptr], align 8
 // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s42conditional_conformance_basic_conformances6SingleVMa"(i64 0, ptr %T)
 // CHECK-NEXT:    [[Single_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[T_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %T.P2, ptr [[T_P2_PTR]], align 8
 // CHECK-NEXT:    [[Single_P1:%.*]] = call ptr @swift_getWitnessTable
@@ -123,7 +123,7 @@ public func single_concrete() {
 // CHECK-STABLE-ABI-FALSE-NEXT:    extractvalue %swift.metadata_response [[T0]], 1
 // CHECK-STABLE-ABI-TRUE-NEXT:     [[T0:%.*]] = call ptr @__swift_instantiateConcreteTypeFromMangledNameAbstract(ptr @"$s42conditional_conformance_basic_conformances6SingleVyAA4IsP2VGMD")
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s42conditional_conformance_basic_conformances4IsP2VAA0F0AAWP", ptr [[A_P2_PTR]], align 8
 
@@ -145,7 +145,7 @@ public func single_concrete() {
 
 // TYPEBYNAME:       cacheIsNull:
 // TYPEBYNAME-NEXT:    [[T0:%.*]] = call ptr @__swift_instantiateConcreteTypeFromMangledNameAbstract(ptr @"$s42conditional_conformance_basic_conformances6SingleVyAA4IsP2VGMD")
-// TYPEBYNAME-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// TYPEBYNAME-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // TYPEBYNAME-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // TYPEBYNAME-NEXT:    store ptr @"$s42conditional_conformance_basic_conformances4IsP2VAA0F0AAWP", ptr [[A_P2_PTR]], align 8
 
@@ -166,7 +166,7 @@ public func single_concrete() {
 // TYPEBYNAME_PRESPECIALIZED-NEXT:    br i1 [[IS_NULL]], label %cacheIsNull, label %cont
 
 // TYPEBYNAME_PRESPECIALIZED:       cacheIsNull:
-// TYPEBYNAME_PRESPECIALIZED-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// TYPEBYNAME_PRESPECIALIZED-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // TYPEBYNAME_PRESPECIALIZED-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // TYPEBYNAME_PRESPECIALIZED-NEXT:    store ptr @"$s42conditional_conformance_basic_conformances4IsP2VAA0F0AAWP", ptr [[A_P2_PTR]], align 8
 
@@ -188,7 +188,7 @@ extension Double: P1 where B: P2, C: P3 {
 
 // witness method for Double.normal
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6DoubleVyxq_GAA2P1A2A2P2RzAA2P3R_rlAaEP6normalyyFTW"(ptr noalias nocapture swiftself %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6DoubleVyxq_GAA2P1A2A2P2RzAA2P3R_rlAaEP6normalyyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[B_P2_i8star:%.*]] = load ptr, ptr [[B_P2_PTR]], align 8
@@ -208,7 +208,7 @@ extension Double: P1 where B: P2, C: P3 {
 
 // witness method for Double.generic
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6DoubleVyxq_GAA2P1A2A2P2RzAA2P3R_rlAaEP7genericyyqd__AaGRd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias nocapture swiftself %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6DoubleVyxq_GAA2P1A2A2P2RzAA2P3R_rlAaEP7genericyyqd__AaGRd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %1, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
@@ -237,7 +237,7 @@ public func double_generic_generic<U: P2, V: P3>(_: U.Type, _: V.Type) {
 // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s42conditional_conformance_basic_conformances6DoubleVMa"(i64 0, ptr %U, ptr %V)
 // CHECK-NEXT:    [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %U.P2, ptr [[B_P2_PTR]], align 8
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -257,7 +257,7 @@ public func double_generic_concrete<X: P2>(_: X.Type) {
 // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s42conditional_conformance_basic_conformances6DoubleVMa"(i64 0, ptr %X, ptr getelementptr inbounds (<{ ptr, ptr, i64, ptr }>, ptr @"$s42conditional_conformance_basic_conformances4IsP3VMf", i32 0, i32 2))
 // CHECK-NEXT:    [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %X.P2, ptr [[B_P2_PTR]], align 8
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -294,7 +294,7 @@ public func double_concrete_concrete() {
 // CHECK-STABLE-ABI-FALSE-NEXT:    extractvalue %swift.metadata_response [[T0]], 1
 // CHECK-STABLE-ABI-TRUE-NEXT:     [[T0:%.*]] = call ptr @__swift_instantiateConcreteTypeFromMangledNameAbstract(ptr @"$s42conditional_conformance_basic_conformances6DoubleVyAA4IsP2VAA0F2P3VGMD")
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s42conditional_conformance_basic_conformances4IsP2VAA0F0AAWP", ptr [[B_P2_PTR]], align 8
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
diff --git a/test/Inputs/conditional_conformance_basic_conformances_future.swift b/test/Inputs/conditional_conformance_basic_conformances_future.swift
index e867a340524c7..a3eb88736d617 100644
--- a/test/Inputs/conditional_conformance_basic_conformances_future.swift
+++ b/test/Inputs/conditional_conformance_basic_conformances_future.swift
@@ -18,7 +18,7 @@ extension Single: P1 where A: P2 {
 
 // witness method for Single.normal
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6SingleVyxGAA2P1A2A2P2RzlAaEP6normalyyFTW"(ptr noalias nocapture swiftself %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6SingleVyxGAA2P1A2A2P2RzlAaEP6normalyyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[A_P2_i8star:%.*]] = load ptr, ptr [[A_P2_PTR]], align 8
@@ -30,7 +30,7 @@ extension Single: P1 where A: P2 {
 
 // witness method for Single.generic
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6SingleVyxGAA2P1A2A2P2RzlAaEP7genericyyqd__AA2P3Rd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias nocapture swiftself %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6SingleVyxGAA2P1A2A2P2RzlAaEP7genericyyqd__AA2P3Rd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %1, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[A_P2_i8star:%.*]] = load ptr, ptr [[A_P2_PTR]], align 8
@@ -48,7 +48,7 @@ public func single_generic<T: P2>(_: T.Type) {
 // CHECK:         %conditional.requirement.buffer = alloca [1 x ptr], align 8
 // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s42conditional_conformance_basic_conformances6SingleVMa"(i64 0, ptr %T)
 // CHECK-NEXT:    [[Single_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[T_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %T.P2, ptr [[T_P2_PTR]], align 8
 // CHECK-NEXT:    [[Single_P1:%.*]] = call ptr @swift_getWitnessTable
@@ -92,7 +92,7 @@ public func single_concrete() {
 // CHECK-NEXT:    br i1 [[IS_NULL]], label %cacheIsNull, label %cont
 
 // CHECK:       cacheIsNull:
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s42conditional_conformance_basic_conformances4IsP2VAA0F0AAWP", ptr [[A_P2_PTR]], align 8
 
@@ -124,7 +124,7 @@ public func single_concrete() {
 
 // TYPEBYNAME:       cacheIsNull:
 // TYPEBYNAME-NEXT:    [[T0:%.*]] = call ptr @__swift_instantiateConcreteTypeFromMangledNameAbstract(ptr @"$s42conditional_conformance_basic_conformances6SingleVyAA4IsP2VGMD")
-// TYPEBYNAME-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// TYPEBYNAME-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // TYPEBYNAME-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // TYPEBYNAME-NEXT:    store ptr @"$s42conditional_conformance_basic_conformances4IsP2VAA0F0AAWP", ptr [[A_P2_PTR]], align 8
 
@@ -145,7 +145,7 @@ public func single_concrete() {
 // TYPEBYNAME_PRESPECIALIZED-NEXT:    br i1 [[IS_NULL]], label %cacheIsNull, label %cont
 
 // TYPEBYNAME_PRESPECIALIZED:       cacheIsNull:
-// TYPEBYNAME_PRESPECIALIZED-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// TYPEBYNAME_PRESPECIALIZED-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // TYPEBYNAME_PRESPECIALIZED-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // TYPEBYNAME_PRESPECIALIZED-NEXT:    store ptr @"$s42conditional_conformance_basic_conformances4IsP2VAA0F0AAWP", ptr [[A_P2_PTR]], align 8
 
@@ -167,7 +167,7 @@ extension Double: P1 where B: P2, C: P3 {
 
 // witness method for Double.normal
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6DoubleVyxq_GAA2P1A2A2P2RzAA2P3R_rlAaEP6normalyyFTW"(ptr noalias nocapture swiftself %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6DoubleVyxq_GAA2P1A2A2P2RzAA2P3R_rlAaEP6normalyyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[B_P2_i8star:%.*]] = load ptr, ptr [[B_P2_PTR]], align 8
@@ -187,7 +187,7 @@ extension Double: P1 where B: P2, C: P3 {
 
 // witness method for Double.generic
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6DoubleVyxq_GAA2P1A2A2P2RzAA2P3R_rlAaEP7genericyyqd__AaGRd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias nocapture swiftself %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s42conditional_conformance_basic_conformances6DoubleVyxq_GAA2P1A2A2P2RzAA2P3R_rlAaEP7genericyyqd__AaGRd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %1, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
@@ -216,7 +216,7 @@ public func double_generic_generic<U: P2, V: P3>(_: U.Type, _: V.Type) {
 // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s42conditional_conformance_basic_conformances6DoubleVMa"(i64 0, ptr %U, ptr %V)
 // CHECK-NEXT:    [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %U.P2, ptr [[B_P2_PTR]], align 8
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -251,7 +251,7 @@ public func double_generic_concrete<X: P2>(_: X.Type) {
 // CHECK-SAME:      )
 // CHECK-SAME:    )
 // CHECK:    [[Double_TYPE:%[0-9]+]] = extractvalue %swift.metadata_response [[Double_TYPE_Response]], 0
-// CHECK:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %X.P2, ptr [[B_P2_PTR]], align 8
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -306,7 +306,7 @@ public func double_concrete_concrete() {
 // CHECK-NEXT:    br i1 [[IS_NULL]], label %cacheIsNull, label %cont
 
 // CHECK:       cacheIsNull:
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [2 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[B_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s42conditional_conformance_basic_conformances4IsP2VAA0F0AAWP", ptr [[B_P2_PTR]], align 8
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
diff --git a/test/Inputs/conditional_conformance_recursive.swift b/test/Inputs/conditional_conformance_recursive.swift
index 37725fc368e1e..76e1bd6da402c 100644
--- a/test/Inputs/conditional_conformance_recursive.swift
+++ b/test/Inputs/conditional_conformance_recursive.swift
@@ -21,5 +21,5 @@ extension Wrapper: P3 where T: P3 { }
 // associated type witness table accessor for A : P2 in Wrapper<T>: P2
 // CHECK-LABEL: define internal swiftcc ptr @"$s33conditional_conformance_recursive7WrapperVyxGAA2P2A2aERzrl1AAA2P1P_AaEPWT"
 // CHECK: [[CONDITIONAL_REQ_BUFFER:%.*]] = alloca [1 x ptr]
-// CHECK: [[FIRST_REQ:%.*]] = getelementptr inbounds [1 x ptr], ptr [[CONDITIONAL_REQ_BUFFER]]
+// CHECK: [[FIRST_REQ:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr [[CONDITIONAL_REQ_BUFFER]]
 // CHECK: call ptr @swift_getWitnessTable
diff --git a/test/Inputs/conditional_conformance_subclass.swift b/test/Inputs/conditional_conformance_subclass.swift
index de35a0d82cc72..e7306a2d5a7fd 100644
--- a/test/Inputs/conditional_conformance_subclass.swift
+++ b/test/Inputs/conditional_conformance_subclass.swift
@@ -16,7 +16,7 @@ extension Base: P1 where A: P2 {
 
 // witness method for Base.normal
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s32conditional_conformance_subclass4BaseCyxGAA2P1A2A2P2RzlAaEP6normalyyFTW"(ptr noalias nocapture swiftself dereferenceable(8) %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s32conditional_conformance_subclass4BaseCyxGAA2P1A2A2P2RzlAaEP6normalyyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(8) %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[A_P2:%.*]] = load ptr, ptr [[A_P2_PTR]], align 8
@@ -27,7 +27,7 @@ extension Base: P1 where A: P2 {
 
 // witness method for Base.generic
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s32conditional_conformance_subclass4BaseCyxGAA2P1A2A2P2RzlAaEP7genericyyqd__AA2P3Rd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias nocapture swiftself dereferenceable(8) %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s32conditional_conformance_subclass4BaseCyxGAA2P1A2A2P2RzlAaEP7genericyyqd__AA2P3Rd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(8) %1, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[A_P2:%.*]] = load ptr, ptr [[A_P2_PTR]], align 8
@@ -50,7 +50,7 @@ public func subclassgeneric_generic<T: P2>(_: T.Type) {
 // CHECK:         %conditional.requirement.buffer = alloca [1 x ptr], align 8
 // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s32conditional_conformance_subclass15SubclassGenericCMa"(i64 0, ptr %T)
 // CHECK-NEXT:    [[SubclassGeneric_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[T_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %T.P2, ptr [[T_P2_PTR]], align 8
 // CHECK-NEXT:    [[Base_P1:%.*]] = call ptr @swift_getWitnessTable
@@ -85,7 +85,7 @@ public func subclassgeneric_concrete() {
 // CHECK-STABLE-ABI-FALSE-NEXT: extractvalue %swift.metadata_response [[T0]], 1
 // CHECK-STABLE-ABI-TRUE-NEXT:  [[T0:%.*]] = call ptr @__swift_instantiateConcreteTypeFromMangledNameAbstract(ptr @"$s32conditional_conformance_subclass15SubclassGenericCyAA4IsP2VGMD")
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s32conditional_conformance_subclass4IsP2VAA0E0AAWP", ptr [[A_P2_PTR]], align 8
 // CHECK-NEXT:    [[Base_P1:%.*]] = call ptr @swift_getWitnessTable
@@ -122,7 +122,7 @@ public func subclassconcrete() {
 // CHECK-NEXT:    [[SubclassConcrete_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 // CHECK-NEXT:    extractvalue %swift.metadata_response [[T0]], 1
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s32conditional_conformance_subclass4IsP2VAA0E0AAWP", ptr [[A_P2_PTR]], align 8
 // CHECK-NEXT:    [[Base_P1:%.*]] = call ptr @swift_getWitnessTable
@@ -158,7 +158,7 @@ public func subclassgenericconcrete() {
 // CHECK-NEXT:    [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s32conditional_conformance_subclass23SubclassGenericConcreteCMa"(i64 255)
 // CHECK-NEXT:    [[SubclassGenericConcrete_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 // CHECK-NEXT:    extractvalue %swift.metadata_response [[T0]], 1
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s32conditional_conformance_subclass4IsP2VAA0E0AAWP", ptr [[A_P2_PTR]], align 8
 // CHECK-NEXT:    [[Base_P1:%.*]] = call ptr @swift_getWitnessTable
diff --git a/test/Inputs/conditional_conformance_subclass_future.swift b/test/Inputs/conditional_conformance_subclass_future.swift
index 4f1a59e28b3f4..1d59ea120d851 100644
--- a/test/Inputs/conditional_conformance_subclass_future.swift
+++ b/test/Inputs/conditional_conformance_subclass_future.swift
@@ -16,7 +16,7 @@ extension Base: P1 where A: P2 {
 
 // witness method for Base.normal
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s32conditional_conformance_subclass4BaseCyxGAA2P1A2A2P2RzlAaEP6normalyyFTW"(ptr noalias nocapture swiftself dereferenceable(8) %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s32conditional_conformance_subclass4BaseCyxGAA2P1A2A2P2RzlAaEP6normalyyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(8) %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[A_P2:%.*]] = load ptr, ptr [[A_P2_PTR]], align 8
@@ -27,7 +27,7 @@ extension Base: P1 where A: P2 {
 
 // witness method for Base.generic
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s32conditional_conformance_subclass4BaseCyxGAA2P1A2A2P2RzlAaEP7genericyyqd__AA2P3Rd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias nocapture swiftself dereferenceable(8) %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s32conditional_conformance_subclass4BaseCyxGAA2P1A2A2P2RzlAaEP7genericyyqd__AA2P3Rd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(8) %1, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[A_P2:%.*]] = load ptr, ptr [[A_P2_PTR]], align 8
@@ -50,7 +50,7 @@ public func subclassgeneric_generic<T: P2>(_: T.Type) {
 // CHECK:         %conditional.requirement.buffer = alloca [1 x ptr], align 8
 // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s32conditional_conformance_subclass15SubclassGenericCMa"(i64 0, ptr %T)
 // CHECK-NEXT:    [[SubclassGeneric_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[T_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %T.P2, ptr [[T_P2_PTR]], align 8
 // CHECK-NEXT:    [[Base_P1:%.*]] = call ptr @swift_getWitnessTable
@@ -89,7 +89,7 @@ public func subclassgeneric_concrete() {
 // linux-android-NEXT: [[T0:%.*]] = call ptr @__swift_instantiateConcreteTypeFromMangledNameAbstract(ptr @"$s32conditional_conformance_subclass15SubclassGenericCyAA4IsP2VGMD")
 // windows-msvc-NEXT: [[T0:%.*]] = call ptr @__swift_instantiateConcreteTypeFromMangledNameAbstract(ptr @"$s32conditional_conformance_subclass15SubclassGenericCyAA4IsP2VGMD")
 
-// CHECK:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s32conditional_conformance_subclass4IsP2VAA0E0AAWP", ptr [[A_P2_PTR]], align 8
 // CHECK-NEXT:    [[Base_P1:%.*]] = call ptr @swift_getWitnessTable
@@ -126,7 +126,7 @@ public func subclassconcrete() {
 // CHECK-NEXT:    [[SubclassConcrete_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 // CHECK-NEXT:    extractvalue %swift.metadata_response [[T0]], 1
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s32conditional_conformance_subclass4IsP2VAA0E0AAWP", ptr [[A_P2_PTR]], align 8
 // CHECK-NEXT:    [[Base_P1:%.*]] = call ptr @swift_getWitnessTable
@@ -162,7 +162,7 @@ public func subclassgenericconcrete() {
 // CHECK-NEXT:    [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s32conditional_conformance_subclass23SubclassGenericConcreteCMa"(i64 255)
 // CHECK-NEXT:    [[SubclassGenericConcrete_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 // CHECK-NEXT:    extractvalue %swift.metadata_response [[T0]], 1
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [1 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[A_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s32conditional_conformance_subclass4IsP2VAA0E0AAWP", ptr [[A_P2_PTR]], align 8
 // CHECK-NEXT:    [[Base_P1:%.*]] = call ptr @swift_getWitnessTable
diff --git a/test/Inputs/conditional_conformance_with_assoc.swift b/test/Inputs/conditional_conformance_with_assoc.swift
index 1aeffe8f2cf56..182dbdb73a84b 100644
--- a/test/Inputs/conditional_conformance_with_assoc.swift
+++ b/test/Inputs/conditional_conformance_with_assoc.swift
@@ -41,7 +41,7 @@ extension Double: P1 where B.AT2: P2, C: P3, B.AT2.AT2.AT3: P3 {
 
 // witness method for Double.normal
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s34conditional_conformance_with_assoc6DoubleVyxq_GAA2P1A2A2P3R_AA2P23AT2RpzAafH_AhaGP3AT3RPzrlAaEP6normalyyFTW"(ptr noalias nocapture swiftself %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s34conditional_conformance_with_assoc6DoubleVyxq_GAA2P1A2A2P3R_AA2P23AT2RpzAafH_AhaGP3AT3RPzrlAaEP6normalyyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[C_P3:%.*]] = load ptr, ptr [[C_P3_PTR]], align 8
@@ -67,7 +67,7 @@ extension Double: P1 where B.AT2: P2, C: P3, B.AT2.AT2.AT3: P3 {
 
 // witness method for Double.generic
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s34conditional_conformance_with_assoc6DoubleVyxq_GAA2P1A2A2P3R_AA2P23AT2RpzAafH_AhaGP3AT3RPzrlAaEP7genericyyqd__AaFRd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias nocapture swiftself %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s34conditional_conformance_with_assoc6DoubleVyxq_GAA2P1A2A2P3R_AA2P23AT2RpzAafH_AhaGP3AT3RPzrlAaEP7genericyyqd__AaFRd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %1, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[C_P3:%.*]] = load ptr, ptr [[C_P3_PTR]], align 8
@@ -103,7 +103,7 @@ public func generic_generic<T: P2, U>(_: T.Type, _: U.Type)
 // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s34conditional_conformance_with_assoc6DoubleVMa"(i64 0, ptr %T, ptr %U, ptr %T.P2)
 // CHECK-NEXT:    [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %U.P3, ptr [[C_P3_PTR]], align 8
 // CHECK-NEXT:    [[B_AT2_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -142,7 +142,7 @@ public func generic_concrete<T: P2>(_: T.Type)
 // CHECK-SAME:         )
 // CHECK-NEXT:    [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s34conditional_conformance_with_assoc4IsP3VAA0F0AAWP", ptr [[C_P3_PTR]], align 8
 // CHECK-NEXT:    [[B_AT2_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -167,7 +167,7 @@ public func concrete_generic<U>(_: U.Type)
 // CHECK:       %conditional.requirement.buffer = alloca [3 x ptr], align 8
 // CHECK:       [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s34conditional_conformance_with_assoc6DoubleVMa"(i64 0, ptr getelementptr inbounds (<{ {{.*}} }>, ptr @"$s34conditional_conformance_with_assoc8IsAlsoP2VMf", i32 0, i32 2), ptr %U, ptr @"$s34conditional_conformance_with_assoc8IsAlsoP2VAA0G0AAWP")
 // CHECK-NEXT:  [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
-// CHECK-NEXT:  [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:  [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:  [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:  store ptr %U.P3, ptr [[C_P3_PTR]], align 8
 // CHECK-NEXT:  [[B_AT2_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -206,7 +206,7 @@ public func concrete_concrete() {
 // CHECK-STABLE-ABI-FALSE-NEXT:   [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 // CHECK-STABLE-ABI-FALSE-NEXT:   extractvalue %swift.metadata_response [[T0]], 1
 // CHECK-STABLE-ABI-TRUE-NEXT:    [[T0:%.*]] = call ptr @__swift_instantiateConcreteTypeFromMangledNameAbstract(ptr @"$s34conditional_conformance_with_assoc6DoubleVyAA8IsAlsoP2VAA0F2P3VGMD")
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s34conditional_conformance_with_assoc4IsP3VAA0F0AAWP", ptr [[C_P3_PTR]], align 8
 // CHECK-NEXT:    [[B_AT2_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
diff --git a/test/Inputs/conditional_conformance_with_assoc_future.swift b/test/Inputs/conditional_conformance_with_assoc_future.swift
index 5dee20e72d072..76b40ea4badc0 100644
--- a/test/Inputs/conditional_conformance_with_assoc_future.swift
+++ b/test/Inputs/conditional_conformance_with_assoc_future.swift
@@ -41,7 +41,7 @@ extension Double: P1 where B.AT2: P2, C: P3, B.AT2.AT2.AT3: P3 {
 
 // witness method for Double.normal
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s34conditional_conformance_with_assoc6DoubleVyxq_GAA2P1A2A2P3R_AA2P23AT2RpzAafH_AhaGP3AT3RPzrlAaEP6normalyyFTW"(ptr noalias nocapture swiftself %0, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s34conditional_conformance_with_assoc6DoubleVyxq_GAA2P1A2A2P3R_AA2P23AT2RpzAafH_AhaGP3AT3RPzrlAaEP6normalyyFTW"(ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %0, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[C_P3:%.*]] = load ptr, ptr [[C_P3_PTR]], align 8
@@ -67,7 +67,7 @@ extension Double: P1 where B.AT2: P2, C: P3, B.AT2.AT2.AT3: P3 {
 
 // witness method for Double.generic
 
-// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s34conditional_conformance_with_assoc6DoubleVyxq_GAA2P1A2A2P3R_AA2P23AT2RpzAafH_AhaGP3AT3RPzrlAaEP7genericyyqd__AaFRd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias nocapture swiftself %1, ptr %Self, ptr %SelfWitnessTable)
+// CHECK-LABEL: define linkonce_odr hidden swiftcc void @"$s34conditional_conformance_with_assoc6DoubleVyxq_GAA2P1A2A2P3R_AA2P23AT2RpzAafH_AhaGP3AT3RPzrlAaEP7genericyyqd__AaFRd__lFTW"(ptr noalias %0, ptr %"\CF\84_1_0", ptr %"\CF\84_1_0.P3", ptr noalias{{( nocapture)?}} swiftself{{( captures\(none\))?}} %1, ptr %Self, ptr %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr %SelfWitnessTable, i32 -1
 // CHECK-NEXT:    [[C_P3:%.*]] = load ptr, ptr [[C_P3_PTR]], align 8
@@ -103,7 +103,7 @@ public func generic_generic<T: P2, U>(_: T.Type, _: U.Type)
 // CHECK:         [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s34conditional_conformance_with_assoc6DoubleVMa"(i64 0, ptr %T, ptr %U, ptr %T.P2)
 // CHECK-NEXT:    [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr %U.P3, ptr [[C_P3_PTR]], align 8
 // CHECK-NEXT:    [[B_AT2_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -143,7 +143,7 @@ public func generic_concrete<T: P2>(_: T.Type)
 // CHECK-SAME:         )
 // CHECK-NEXT:    [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
 
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s34conditional_conformance_with_assoc4IsP3VAA0F0AAWP", ptr [[C_P3_PTR]], align 8
 // CHECK-NEXT:    [[B_AT2_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -168,7 +168,7 @@ public func concrete_generic<U>(_: U.Type)
 // CHECK:       %conditional.requirement.buffer = alloca [3 x ptr], align 8
 // CHECK:       [[T0:%.*]] = call swiftcc %swift.metadata_response @"$s34conditional_conformance_with_assoc6DoubleVMa"(i64 0, ptr getelementptr inbounds (<{ {{.*}} }>, ptr @"$s34conditional_conformance_with_assoc8IsAlsoP2VMf", i32 0, i32 2), ptr %U, ptr @"$s34conditional_conformance_with_assoc8IsAlsoP2VAA0G0AAWP")
 // CHECK-NEXT:  [[Double_TYPE:%.*]] = extractvalue %swift.metadata_response [[T0]], 0
-// CHECK-NEXT:  [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:  [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:  [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:  store ptr %U.P3, ptr [[C_P3_PTR]], align 8
 // CHECK-NEXT:  [[B_AT2_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
@@ -215,7 +215,7 @@ public func concrete_concrete() {
 // CHECK-NEXT:    br i1 [[IS_NULL]], label %cacheIsNull, label %cont
 
 // CHECK:       cacheIsNull:
-// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
+// CHECK-NEXT:    [[CONDITIONAL_REQUIREMENTS:%.*]] = getelementptr inbounds{{.*}} [3 x ptr], ptr %conditional.requirement.buffer, i32 0, i32 0
 // CHECK-NEXT:    [[C_P3_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 0
 // CHECK-NEXT:    store ptr @"$s34conditional_conformance_with_assoc4IsP3VAA0F0AAWP", ptr [[C_P3_PTR]], align 8
 // CHECK-NEXT:    [[B_AT2_P2_PTR:%.*]] = getelementptr inbounds ptr, ptr [[CONDITIONAL_REQUIREMENTS]], i32 1
diff --git a/test/Inputs/custom-modules/availability-domains/Lakes.h b/test/Inputs/custom-modules/availability-domains/Lakes.h
new file mode 100644
index 0000000000000..5633fa29e4d2d
--- /dev/null
+++ b/test/Inputs/custom-modules/availability-domains/Lakes.h
@@ -0,0 +1,16 @@
+#include <availability_domain.h>
+
+int huron_pred(void);
+
+CLANG_ENABLED_AVAILABILITY_DOMAIN(Salt);
+CLANG_DISABLED_AVAILABILITY_DOMAIN(Erie);
+CLANG_DYNAMIC_AVAILABILITY_DOMAIN(Huron, huron_pred);
+
+#define AVAIL 0
+#define UNAVAIL 1
+
+__attribute__((availability(domain:Salt, AVAIL)))
+void available_in_salt(void);
+
+#undef UNAVAIL
+#undef AVAIL
diff --git a/test/Inputs/custom-modules/availability-domains/Oceans.h b/test/Inputs/custom-modules/availability-domains/Oceans.h
new file mode 100644
index 0000000000000..57a50b7915a9f
--- /dev/null
+++ b/test/Inputs/custom-modules/availability-domains/Oceans.h
@@ -0,0 +1,24 @@
+#include <Rivers.h>
+#include <availability_domain.h>
+
+int arctic_pred(void);
+int pacific_pred(void);
+
+CLANG_DYNAMIC_AVAILABILITY_DOMAIN(Arctic, arctic_pred);
+CLANG_DYNAMIC_AVAILABILITY_DOMAIN(Pacific, pacific_pred);
+
+#define AVAIL 0
+#define UNAVAIL 1
+
+__attribute__((availability(domain:Arctic, AVAIL)))
+void available_in_arctic(void);
+
+__attribute__((availability(domain:Pacific, UNAVAIL)))
+void unavailable_in_pacific(void);
+
+__attribute__((availability(domain:Colorado, AVAIL)))
+__attribute__((availability(domain:Pacific, AVAIL)))
+void available_in_colorado_river_delta(void);
+
+#undef UNAVAIL
+#undef AVAIL
diff --git a/test/Inputs/custom-modules/availability-domains/Rivers.h b/test/Inputs/custom-modules/availability-domains/Rivers.h
new file mode 100644
index 0000000000000..e36c41d83e001
--- /dev/null
+++ b/test/Inputs/custom-modules/availability-domains/Rivers.h
@@ -0,0 +1,15 @@
+#include <availability_domain.h>
+
+CLANG_DISABLED_AVAILABILITY_DOMAIN(Colorado);
+
+__attribute__((deprecated("Use Colorado instead")))
+CLANG_DISABLED_AVAILABILITY_DOMAIN(Grand);
+
+#define AVAIL 0
+#define UNAVAIL 1
+
+__attribute__((availability(domain:Colorado, AVAIL)))
+void available_in_colorado(void);
+
+#undef UNAVAIL
+#undef AVAIL
diff --git a/test/Inputs/custom-modules/availability-domains/Seas.h b/test/Inputs/custom-modules/availability-domains/Seas.h
new file mode 100644
index 0000000000000..4a1a4e3b1fdb9
--- /dev/null
+++ b/test/Inputs/custom-modules/availability-domains/Seas.h
@@ -0,0 +1,25 @@
+#include <availability_domain.h>
+
+int aegean_pred(void);
+
+CLANG_ENABLED_AVAILABILITY_DOMAIN(Baltic);
+CLANG_ALWAYS_ENABLED_AVAILABILITY_DOMAIN(Bering);
+CLANG_DISABLED_AVAILABILITY_DOMAIN(Mediterranean);
+CLANG_DYNAMIC_AVAILABILITY_DOMAIN(Aegean, aegean_pred);
+__attribute__((deprecated))
+CLANG_ALWAYS_ENABLED_AVAILABILITY_DOMAIN(Aral);
+
+#define AVAIL 0
+#define UNAVAIL 1
+
+__attribute__((availability(domain:Baltic, AVAIL)))
+void available_in_baltic(void);
+
+__attribute__((availability(domain:Bering, AVAIL)))
+void available_in_bering(void);
+
+__attribute__((availability(domain:Bering, UNAVAIL)))
+void unavailable_in_bering(void);
+
+#undef UNAVAIL
+#undef AVAIL
diff --git a/test/Inputs/custom-modules/availability-domains/module.modulemap b/test/Inputs/custom-modules/availability-domains/module.modulemap
new file mode 100644
index 0000000000000..3d9316f279f71
--- /dev/null
+++ b/test/Inputs/custom-modules/availability-domains/module.modulemap
@@ -0,0 +1,19 @@
+module Oceans {
+  header "Oceans.h"
+  export *
+}
+
+module Rivers {
+  header "Rivers.h"
+  export *
+}
+
+module Seas {
+  header "Seas.h"
+  export *
+}
+
+module Lakes {
+  header "Lakes.h"
+  export *
+}
diff --git a/test/Inputs/lazy_typecheck.swift b/test/Inputs/lazy_typecheck.swift
index 553a8f82d6b25..a03767950ee26 100644
--- a/test/Inputs/lazy_typecheck.swift
+++ b/test/Inputs/lazy_typecheck.swift
@@ -64,7 +64,7 @@ public func publicFuncWithOpaqueReturnType() -> some PublicProto {
 
 @available(SwiftStdlib 5.1, *)
 @_alwaysEmitIntoClient public func publicAEICFuncWithOpaqueReturnType() -> some Any {
-  if #available(macOS 20, *) {
+  if #available(macOS 99, *) {
     return 3
   } else {
     return "hi"
@@ -109,6 +109,30 @@ var internalGlobalVar: NoTypecheck = NoTypecheck()
 var internalGlobalVarInferredType = NoTypecheck()
 var internalGlobalTypealiasVar: PublicIntAlias = NoTypecheck.int
 
+@backDeployed(before: macOS 99, iOS 99, tvOS 99, watchOS 99, visionOS 99)
+public private(set) var publicGlobalVarBackDeployedWithPrivateSetter: Int {
+  get { 0 }
+  set { // Implicitly not @backDeployed.
+    _ = NoTypecheck()
+  }
+}
+
+@backDeployed(before: macOS 99, iOS 99, tvOS 99, watchOS 99, visionOS 99)
+public internal(set) var publicGlobalVarBackDeployedWithInternalSetter: Int {
+  get { 0 }
+  set { // Implicitly not @backDeployed.
+    _ = NoTypecheck()
+  }
+}
+
+@backDeployed(before: macOS 99, iOS 99, tvOS 99, watchOS 99, visionOS 99)
+public package(set) var publicGlobalVarBackDeployedWithPackageSetter: Int {
+  get { 0 }
+  set { // Implicitly not @backDeployed.
+    _ = NoTypecheck()
+  }
+}
+
 // MARK: - Nominal types
 
 public protocol EmptyPublicProto {}
@@ -378,3 +402,7 @@ extension PublicStruct {
     lhs = rhs
   }
 }
+
+public class LazyPropertyWithClosureType {
+  public lazy var lazyVar: Int = { 2 }()
+}
diff --git a/test/Inputs/lazy_typecheck_client.swift b/test/Inputs/lazy_typecheck_client.swift
index 8f251d5867476..1dbfc33716921 100644
--- a/test/Inputs/lazy_typecheck_client.swift
+++ b/test/Inputs/lazy_typecheck_client.swift
@@ -142,3 +142,8 @@ func testOperators() {
   var a: PublicStruct
   a <<< PublicStruct(x: 2)
 }
+
+func testLazyPropertyWithInitClosureReference(t: LazyPropertyWithClosureType) {
+  _ = t.lazyVar
+  t.lazyVar = 42
+}
diff --git a/test/InterfaceHash/added_method-type.swift b/test/InterfaceHash/added_method-type.swift
index cdfac2368a995..b62c94e855e47 100644
--- a/test/InterfaceHash/added_method-type.swift
+++ b/test/InterfaceHash/added_method-type.swift
@@ -3,10 +3,10 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_class_private_property.swift b/test/InterfaceHash/added_private_class_private_property.swift
index 59c87f47f9309..d467b9b840533 100644
--- a/test/InterfaceHash/added_private_class_private_property.swift
+++ b/test/InterfaceHash/added_private_class_private_property.swift
@@ -1,9 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_class_property.swift b/test/InterfaceHash/added_private_class_property.swift
index 3fdd3686f97d9..4a5deedd5b70b 100644
--- a/test/InterfaceHash/added_private_class_property.swift
+++ b/test/InterfaceHash/added_private_class_property.swift
@@ -1,9 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_enum_private_property.swift b/test/InterfaceHash/added_private_enum_private_property.swift
index 6c667a2c97098..6bec4ceb7a243 100644
--- a/test/InterfaceHash/added_private_enum_private_property.swift
+++ b/test/InterfaceHash/added_private_enum_private_property.swift
@@ -3,10 +3,10 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_enum_property.swift b/test/InterfaceHash/added_private_enum_property.swift
index 33de0a3d6bf95..e04c4ca75ce86 100644
--- a/test/InterfaceHash/added_private_enum_property.swift
+++ b/test/InterfaceHash/added_private_enum_property.swift
@@ -3,10 +3,10 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_method.swift b/test/InterfaceHash/added_private_method.swift
index 759a4b0077ece..fa52408149e8a 100644
--- a/test/InterfaceHash/added_private_method.swift
+++ b/test/InterfaceHash/added_private_method.swift
@@ -3,10 +3,10 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_method_value_types.swift b/test/InterfaceHash/added_private_method_value_types.swift
index b3cc211c871bf..75467b6877891 100644
--- a/test/InterfaceHash/added_private_method_value_types.swift
+++ b/test/InterfaceHash/added_private_method_value_types.swift
@@ -3,10 +3,10 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_protocol_method.swift b/test/InterfaceHash/added_private_protocol_method.swift
index a1afc8442acaa..05556db29b007 100644
--- a/test/InterfaceHash/added_private_protocol_method.swift
+++ b/test/InterfaceHash/added_private_protocol_method.swift
@@ -3,10 +3,10 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_protocol_property.swift b/test/InterfaceHash/added_private_protocol_property.swift
index 599109568d87a..bac725ea2ad48 100644
--- a/test/InterfaceHash/added_private_protocol_property.swift
+++ b/test/InterfaceHash/added_private_protocol_property.swift
@@ -3,10 +3,10 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_struct_private_property.swift b/test/InterfaceHash/added_private_struct_private_property.swift
index 1e1af903673a8..710d8f45f9f54 100644
--- a/test/InterfaceHash/added_private_struct_private_property.swift
+++ b/test/InterfaceHash/added_private_struct_private_property.swift
@@ -3,10 +3,10 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/added_private_struct_property.swift b/test/InterfaceHash/added_private_struct_property.swift
index 0b14dd798d38f..bd70145ff68c2 100644
--- a/test/InterfaceHash/added_private_struct_property.swift
+++ b/test/InterfaceHash/added_private_struct_property.swift
@@ -3,10 +3,10 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/edited_method_body.swift b/test/InterfaceHash/edited_method_body.swift
index d6f04212398e2..9a8feb02b84c8 100644
--- a/test/InterfaceHash/edited_method_body.swift
+++ b/test/InterfaceHash/edited_method_body.swift
@@ -4,10 +4,10 @@
 // RUN: %empty-directory(%t)
 // RUN: %empty-directory(%t/ModuleCache)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: env SWIFT_FORCE_MODULE_LOADING=prefer-interface %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main -module-cache-path %t/ModuleCache -Rmodule-loading
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: env SWIFT_FORCE_MODULE_LOADING=prefer-interface %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main -module-cache-path %t/ModuleCache -Rmodule-loading
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/InterfaceHash/edited_property_getter.swift b/test/InterfaceHash/edited_property_getter.swift
index 17133f96c4263..d98f8625e5729 100644
--- a/test/InterfaceHash/edited_property_getter.swift
+++ b/test/InterfaceHash/edited_property_getter.swift
@@ -4,10 +4,10 @@
 // RUN: %empty-directory(%t)
 // RUN: %empty-directory(%t/ModuleCache)
 // RUN: %{python} %utils/split_file.py -o %t %s
-// RUN: cp %t/{a,x}.swift
+// RUN: cp %t/a.swift %t/x.swift
 // RUN: env SWIFT_FORCE_MODULE_LOADING=prefer-interface %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main -module-cache-path %t/ModuleCache -Rmodule-loading
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/a-processed.swiftdeps
-// RUN: cp %t/{b,x}.swift
+// RUN: cp %t/b.swift %t/x.swift
 // RUN: env SWIFT_FORCE_MODULE_LOADING=prefer-interface %target-swift-frontend -typecheck -primary-file %t/x.swift -emit-reference-dependencies-path %t/x.swiftdeps -module-name main -module-cache-path %t/ModuleCache -Rmodule-loading
 // RUN: %{python} %S/../Inputs/process_fine_grained_swiftdeps_with_fingerprints.py %swift-dependency-tool %t/x.swiftdeps > %t/b-processed.swiftdeps
 
diff --git a/test/Interop/C/bounds-safety/Inputs/bounds-attributed-function.h b/test/Interop/C/bounds-safety/Inputs/bounds-attributed-function.h
new file mode 100644
index 0000000000000..46a4b96eaacb1
--- /dev/null
+++ b/test/Interop/C/bounds-safety/Inputs/bounds-attributed-function.h
@@ -0,0 +1,56 @@
+#pragma once
+
+#include <ptrcheck.h>
+#include <stdarg.h>
+
+// Test __counted_by, __sized_by, __ended_by, __single, __indexable and __bidi_indexable pointers
+// in function parameters, return values, nested and unnested, pointing to void, char and int.
+// Also test VLAs, and incomplete pointer type with __counted_by, since they are pretty much the same
+// as __counted_by pointers in the -fbounds-safety model.
+
+#ifndef __unsafe_late_const
+#define __unsafe_late_const
+#endif
+
+int * __counted_by(len) a(int *__counted_by(len) p, int len);
+char * __counted_by(len) b(char *__counted_by(len) p, int len);
+char * __sized_by(len) c(char *__sized_by(len) p, int len);
+void * __sized_by(len) d(void *__sized_by(len) p, int len);
+int * __sized_by(len) e(int *__sized_by(len) p, int len);
+
+int * __ended_by(end) f(int *__ended_by(end) p, int * end);
+void * __ended_by(end) g(void *__ended_by(end) p, void * end);
+
+char * __null_terminated h(char *__null_terminated p);
+const char * i(const char * p);
+
+char * __single j(char *__single p);
+void *__single k(void *__single p);
+
+#if __has_ptrcheck
+// __indexable and __bidi_indexable are not defined unless -fbounds-safety is enabled
+char * __indexable l(char *__indexable p);
+void *__indexable m(void *__indexable p);
+
+char * __bidi_indexable n(char *__bidi_indexable p);
+void * __bidi_indexable o(void *__bidi_indexable p);
+#endif
+
+#if !__cplusplus
+// No VLAs in C++
+void p(int len, int p[len]);
+#endif
+void q(int p[__counted_by(len)], int len);
+
+void r(int * __counted_by(*len) *__single p, int *len);
+char * __null_terminated *__null_terminated s(char * __null_terminated *__null_terminated p);
+char * __single *__single t(char * __single *__single p);
+
+const int len1 = 7;
+int * __counted_by(len1) u(int * __counted_by(len1) p);
+
+int len2 __unsafe_late_const;
+int * __counted_by(len2) v(int * __counted_by(len2) p);
+
+// -fbounds-safety can sometimes affect va_list
+void w(va_list p);
diff --git a/test/Interop/C/bounds-safety/Inputs/bounds-attributed-global.h b/test/Interop/C/bounds-safety/Inputs/bounds-attributed-global.h
new file mode 100644
index 0000000000000..7f746134c601b
--- /dev/null
+++ b/test/Interop/C/bounds-safety/Inputs/bounds-attributed-global.h
@@ -0,0 +1,13 @@
+#pragma once
+
+#include <ptrcheck.h>
+
+extern int len;
+extern int a[__counted_by(len)]; // expected-note{{'a' declared here}}
+
+const char * __null_terminated b = "b";
+
+extern int * __single * __single c;
+#if __has_ptrcheck
+extern int * __bidi_indexable d;
+#endif
diff --git a/test/Interop/C/bounds-safety/Inputs/bounds-attributed-struct.h b/test/Interop/C/bounds-safety/Inputs/bounds-attributed-struct.h
new file mode 100644
index 0000000000000..739c615e574b2
--- /dev/null
+++ b/test/Interop/C/bounds-safety/Inputs/bounds-attributed-struct.h
@@ -0,0 +1,90 @@
+#pragma once
+
+#include <ptrcheck.h>
+
+// Test __counted_by, __sized_by, __ended_by, __single, __indexable and __bidi_indexable pointers
+// in function parameters, return values, nested and unnested, pointing to void, char and int.
+// Also test VLAs, and incomplete pointer type with __counted_by, since they are pretty much the same
+// as __counted_by pointers in the -fbounds-safety model.
+
+struct a {
+    int * __counted_by(len) a;
+    int len;
+};
+struct a *a(struct a);
+
+struct b {
+    int * __sized_by(len) a;
+    int len;
+};
+struct b *b(struct b);
+
+struct c {
+    char * __sized_by(len) a;
+    int len;
+};
+struct c *c(struct c);
+
+struct d {
+    void * __sized_by(len) a;
+    int len;
+};
+struct d *d(struct d);
+
+struct e {
+    void * __single a;
+    int * __single b;
+};
+struct e *e(struct e);
+
+struct f {
+    const char * a;
+    char * __null_terminated b;
+};
+struct f *f(struct f);
+
+#if __has_ptrcheck
+struct g {
+    void * __bidi_indexable a;
+    int * __bidi_indexable b;
+};
+struct g *g(struct g);
+
+struct h {
+    void * __indexable a;
+    int * __indexable b;
+};
+struct h *h(struct h);
+#endif
+
+struct i {
+    int len;
+    int a[__counted_by(len)]; // expected-note {{field 'a' unavailable (cannot import)}}
+};
+struct i *__single i(struct i *);
+
+const int len1 = 7;
+struct j {
+    int * __counted_by(len1) a;
+    void * __sized_by(len1) b;
+};
+struct j *j(struct j);
+
+int len2 __unsafe_late_const;
+struct k {
+    int * __counted_by(len2) a;
+    void * __sized_by(len2) b;
+};
+struct k *k(struct k);
+
+struct l {
+    int * __ended_by(end) a;
+    int * end;
+};
+struct l *l(struct l);
+
+struct m {
+    void * __ended_by(end) a;
+    void * end;
+};
+struct m *m(struct m);
diff --git a/test/Interop/C/bounds-safety/Inputs/module.modulemap b/test/Interop/C/bounds-safety/Inputs/module.modulemap
new file mode 100644
index 0000000000000..a484dbbb430d1
--- /dev/null
+++ b/test/Interop/C/bounds-safety/Inputs/module.modulemap
@@ -0,0 +1,12 @@
+module BoundsAttributedFunction {
+  header "bounds-attributed-function.h"
+  export *
+}
+module BoundsAttributedGlobal {
+  header "bounds-attributed-global.h"
+  export *
+}
+module BoundsAttributedStruct {
+  header "bounds-attributed-struct.h"
+  export *
+}
diff --git a/test/Interop/C/bounds-safety/import-bounds-attributed-function.swift b/test/Interop/C/bounds-safety/import-bounds-attributed-function.swift
new file mode 100644
index 0000000000000..b9b3f26903db1
--- /dev/null
+++ b/test/Interop/C/bounds-safety/import-bounds-attributed-function.swift
@@ -0,0 +1,85 @@
+// RUN: %target-swift-ide-test -Xcc -fexperimental-bounds-safety-attributes -print-module -module-to-print=BoundsAttributedFunction -I %S/Inputs -source-filename=x | %FileCheck %s --check-prefixes=CHECK,C-ONLY
+// RUN: %target-swift-ide-test -Xcc -fexperimental-bounds-safety-attributes -print-module -module-to-print=BoundsAttributedFunction -I %S/Inputs -source-filename=x -cxx-interoperability-mode=default | %FileCheck %s
+// RUN: %target-swift-ide-test -Xcc -fbounds-safety -disable-objc-interop -print-module -module-to-print=BoundsAttributedFunction -I %S/Inputs -source-filename=x | %FileCheck %s --check-prefixes=CHECK,BOUNDS-SAFETY,C-ONLY
+
+// This test case checks that ClangImporter can import declarations using various bounds attributes,
+// rather than being marked unavailable because of an unknown type.
+
+// CHECK:      func a(_ p: UnsafeMutablePointer<Int{{[0-9]+}}>!, _ len: Int{{[0-9]+}}) -> UnsafeMutablePointer<Int{{[0-9]+}}>!
+// CHECK-NEXT: func b(_ p: UnsafeMutablePointer<CChar>!, _ len: Int{{[0-9]+}}) -> UnsafeMutablePointer<CChar>!
+// CHECK-NEXT: func c(_ p: UnsafeMutablePointer<CChar>!, _ len: Int{{[0-9]+}}) -> UnsafeMutablePointer<CChar>!
+// CHECK-NEXT: func d(_ p: UnsafeMutableRawPointer!, _ len: Int{{[0-9]+}}) -> UnsafeMutableRawPointer!
+// CHECK-NEXT: func e(_ p: UnsafeMutablePointer<Int{{[0-9]+}}>!, _ len: Int{{[0-9]+}}) -> UnsafeMutablePointer<Int{{[0-9]+}}>!
+// CHECK-NEXT: func f(_ p: UnsafeMutablePointer<Int{{[0-9]+}}>!, _ end: UnsafeMutablePointer<Int{{[0-9]+}}>!) -> UnsafeMutablePointer<Int{{[0-9]+}}>!
+// CHECK-NEXT: func g(_ p: UnsafeMutableRawPointer!, _ end: UnsafeMutableRawPointer!) -> UnsafeMutableRawPointer!
+// CHECK-NEXT: func h(_ p: UnsafeMutablePointer<CChar>!) -> UnsafeMutablePointer<CChar>!
+// CHECK-NEXT: func i(_ p: UnsafePointer<CChar>!) -> UnsafePointer<CChar>!
+// CHECK-NEXT: func j(_ p: UnsafeMutablePointer<CChar>!) -> UnsafeMutablePointer<CChar>!
+// CHECK-NEXT: func k(_ p: UnsafeMutableRawPointer!) -> UnsafeMutableRawPointer!
+
+// BOUNDS-SAFETY-NEXT: func l(_ p: UnsafeMutablePointer<CChar>!) -> UnsafeMutablePointer<CChar>!
+// BOUNDS-SAFETY-NEXT: func m(_ p: UnsafeMutableRawPointer!) -> UnsafeMutableRawPointer!
+// BOUNDS-SAFETY-NEXT: func n(_ p: UnsafeMutablePointer<CChar>!) -> UnsafeMutablePointer<CChar>!
+// BOUNDS-SAFETY-NEXT: func o(_ p: UnsafeMutableRawPointer!) -> UnsafeMutableRawPointer!
+
+// C-ONLY-NEXT: func p(_ len: Int{{[0-9]+}}, _ p: UnsafeMutablePointer<Int{{[0-9]+}}>!)
+
+// CHECK-NEXT: func q(_ p: UnsafeMutablePointer<Int{{[0-9]+}}>!, _ len: Int{{[0-9]+}})
+// CHECK-NEXT: func r(_ p: UnsafeMutablePointer<UnsafeMutablePointer<Int{{[0-9]+}}>?>!, _ len: UnsafeMutablePointer<Int{{[0-9]+}}>!)
+// CHECK-NEXT: func s(_ p: UnsafeMutablePointer<UnsafeMutablePointer<CChar>?>!) -> UnsafeMutablePointer<UnsafeMutablePointer<CChar>?>!
+// CHECK-NEXT: func t(_ p: UnsafeMutablePointer<UnsafeMutablePointer<CChar>?>!) -> UnsafeMutablePointer<UnsafeMutablePointer<CChar>?>!
+// CHECK-NEXT: var len1: Int{{[0-9]+}} { get }
+// CHECK-NEXT: func u(_ p: UnsafeMutablePointer<Int{{[0-9]+}}>!) -> UnsafeMutablePointer<Int{{[0-9]+}}>!
+// CHECK-NEXT: var len2: Int{{[0-9]+}}
+// CHECK-NEXT: func v(_ p: UnsafeMutablePointer<Int{{[0-9]+}}>!) -> UnsafeMutablePointer<Int{{[0-9]+}}>!
+
+
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -D C_ONLY
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -cxx-interoperability-mode=default
+// RUN: %target-swift-frontend -Xcc -fbounds-safety -disable-objc-interop -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -D C_ONLY -D BOUNDS_SAFETY
+
+import BoundsAttributedFunction
+
+func call(_ mutIntPtr: UnsafeMutablePointer<CInt>,
+          _ mutCharPtr: UnsafeMutablePointer<CChar>,
+          _ mutRawPtr: UnsafeMutableRawPointer,
+          _ constCharPtr: UnsafePointer<CChar>,
+          _ mutMutIntPtrPtr: UnsafeMutablePointer<UnsafeMutablePointer<CInt>?>!,
+          _ mutMutCharPtrPtr: UnsafeMutablePointer<UnsafeMutablePointer<CChar>?>!,
+          _ int: CInt,
+          _ args: CVaListPointer) {
+    let _ = a(mutIntPtr, int)
+    let _ = b(mutCharPtr, int)
+    let _ = c(mutCharPtr, int)
+    let _ = d(mutRawPtr, int)
+    let _ = e(mutIntPtr, int)
+    let _ = f(mutIntPtr, mutIntPtr)
+    let _ = g(mutRawPtr, mutRawPtr)
+    let _ = h(mutCharPtr)
+    let _ = i(constCharPtr)
+    let _ = j(mutCharPtr)
+    let _ = k(mutRawPtr)
+
+#if BOUNDS_SAFETY
+    let _ = l(mutIntPtr)
+    let _ = m(mutRawPtr)
+    let _ = n(mutIntPtr)
+    let _ = o(mutRawPtr)
+#endif
+
+#if C_ONLY
+    let _ = p(int, mutIntPtr)
+#endif
+
+    let _ = q(mutIntPtr, int)
+    let _ = r(mutMutIntPtrPtr, mutIntPtr)
+    let _ = s(mutMutCharPtrPtr)
+    let _ = t(mutMutCharPtrPtr)
+    let _ = len1
+    let _ = u(mutIntPtr)
+    let _ = len2
+    len2 = 37
+    let _ = v(mutIntPtr)
+
+    let _ = w(args)
+}
diff --git a/test/Interop/C/bounds-safety/import-bounds-attributed-global.swift b/test/Interop/C/bounds-safety/import-bounds-attributed-global.swift
new file mode 100644
index 0000000000000..999be225a2bdc
--- /dev/null
+++ b/test/Interop/C/bounds-safety/import-bounds-attributed-global.swift
@@ -0,0 +1,36 @@
+// RUN: %target-swift-ide-test -Xcc -fexperimental-bounds-safety-attributes -print-module -module-to-print=BoundsAttributedGlobal -I %S/Inputs -source-filename=x | %FileCheck %s --check-prefixes=CHECK,C-ONLY
+// RUN: %target-swift-ide-test -Xcc -fexperimental-bounds-safety-attributes -print-module -module-to-print=BoundsAttributedGlobal -I %S/Inputs -source-filename=x -cxx-interoperability-mode=swift-6 -Xcc -std=c++20 | %FileCheck %s
+// RUN: %target-swift-ide-test -Xcc -fbounds-safety -disable-objc-interop -print-module -module-to-print=BoundsAttributedGlobal -I %S/Inputs -source-filename=x | %FileCheck %s --check-prefixes=CHECK,BOUNDS-SAFETY,C-ONLY
+
+// This test case checks that ClangImporter can import declarations using various bounds attributes,
+// rather than being marked unavailable because of an unknown type.
+
+// CHECK:      var len: Int32
+// CHECK-NEXT: var a: <<error type>>
+// CHECK-NEXT: var b: UnsafePointer<CChar>!
+// CHECK-NEXT: var c: UnsafeMutablePointer<UnsafeMutablePointer<Int32>?>!
+// BOUNDS-SAFETY-NEXT: var d: UnsafeMutablePointer<Int32>!
+
+
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -cxx-interoperability-mode=swift-6
+// RUN: %target-swift-frontend -Xcc -fbounds-safety -disable-objc-interop -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -D BOUNDS_SAFETY
+
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -verify -verify-additional-file %S/Inputs/bounds-attributed-global.h -D VERIFY
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -cxx-interoperability-mode=swift-6 -verify -verify-additional-file %S/Inputs/bounds-attributed-global.h -D VERIFY
+// RUN: %target-swift-frontend -Xcc -fbounds-safety -disable-objc-interop -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -verify -verify-additional-file %S/Inputs/bounds-attributed-global.h -D BOUNDS_SAFETY -D VERIFY
+
+import BoundsAttributedGlobal
+
+func access() {
+#if VERIFY
+// rdar://152293598 ([ClangImporter] Importing global array errors on macOS and Linux, but not on Windows)
+// XFAIL: OS=windows-msvc
+    let _ = a // expected-error{{cannot reference invalid declaration 'a'}} rdar://151665752
+#endif
+    let _ = b.pointee
+    let _ = c.pointee!.pointee
+#if BOUNDS_SAFETY
+    let _ = d.pointee
+#endif
+}
diff --git a/test/Interop/C/bounds-safety/import-bounds-attributed-struct.swift b/test/Interop/C/bounds-safety/import-bounds-attributed-struct.swift
new file mode 100644
index 0000000000000..89e1373b5e9e8
--- /dev/null
+++ b/test/Interop/C/bounds-safety/import-bounds-attributed-struct.swift
@@ -0,0 +1,153 @@
+// RUN: %target-swift-ide-test -Xcc -fexperimental-bounds-safety-attributes -print-module -module-to-print=BoundsAttributedStruct -I %S/Inputs -source-filename=x | %FileCheck %s
+// RUN: %target-swift-ide-test -Xcc -fexperimental-bounds-safety-attributes -print-module -module-to-print=BoundsAttributedStruct -I %S/Inputs -source-filename=x -cxx-interoperability-mode=swift-6 -Xcc -std=c++20 | %FileCheck %s
+// RUN: %target-swift-ide-test -Xcc -fbounds-safety -disable-objc-interop -print-module -module-to-print=BoundsAttributedStruct -I %S/Inputs -source-filename=x | %FileCheck %s --check-prefixes=CHECK,BOUNDS-SAFETY
+
+// This test case checks that ClangImporter can import declarations using various bounds attributes,
+// rather than being marked unavailable because of an unknown type.
+
+// CHECK:      struct a {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   init(a: UnsafeMutablePointer<Int{{[0-9]+}}>!, len: Int{{[0-9]+}})
+// CHECK-NEXT:   var a: UnsafeMutablePointer<Int{{[0-9]+}}>!
+// CHECK-NEXT:   var len: Int{{[0-9]+}}
+// CHECK-NEXT: }
+// CHECK-NEXT: func a(_: a) -> UnsafeMutablePointer<a>!
+// CHECK-NEXT: struct b {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   init(a: UnsafeMutablePointer<Int{{[0-9]+}}>!, len: Int{{[0-9]+}})
+// CHECK-NEXT:   var a: UnsafeMutablePointer<Int{{[0-9]+}}>!
+// CHECK-NEXT:   var len: Int{{[0-9]+}}
+// CHECK-NEXT: }
+// CHECK-NEXT: func b(_: b) -> UnsafeMutablePointer<b>!
+// CHECK-NEXT: struct c {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   init(a: UnsafeMutablePointer<CChar>!, len: Int{{[0-9]+}})
+// CHECK-NEXT:   var a: UnsafeMutablePointer<CChar>!
+// CHECK-NEXT:   var len: Int{{[0-9]+}}
+// CHECK-NEXT: }
+// CHECK-NEXT: func c(_: c) -> UnsafeMutablePointer<c>!
+// CHECK-NEXT: struct d {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   init(a: UnsafeMutableRawPointer!, len: Int{{[0-9]+}})
+// CHECK-NEXT:   var a: UnsafeMutableRawPointer!
+// CHECK-NEXT:   var len: Int{{[0-9]+}}
+// CHECK-NEXT: }
+// CHECK-NEXT: func d(_: d) -> UnsafeMutablePointer<d>!
+// CHECK-NEXT: struct e {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   init(a: UnsafeMutableRawPointer!, b: UnsafeMutablePointer<Int{{[0-9]+}}>!)
+// CHECK-NEXT:   var a: UnsafeMutableRawPointer!
+// CHECK-NEXT:   var b: UnsafeMutablePointer<Int{{[0-9]+}}>!
+// CHECK-NEXT: }
+// CHECK-NEXT: func e(_: e) -> UnsafeMutablePointer<e>!
+// CHECK-NEXT: struct f {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   init(a: UnsafePointer<CChar>!, b: UnsafeMutablePointer<CChar>!)
+// CHECK-NEXT:   var a: UnsafePointer<CChar>!
+// CHECK-NEXT:   var b: UnsafeMutablePointer<CChar>!
+// CHECK-NEXT: }
+// CHECK-NEXT: func f(_: f) -> UnsafeMutablePointer<f>!
+
+// BOUNDS-SAFETY-NEXT: struct g {
+// BOUNDS-SAFETY-NEXT:  init()
+// BOUNDS-SAFETY-NEXT:  init(a: UnsafeMutableRawPointer!, b: UnsafeMutablePointer<Int32>!)
+// BOUNDS-SAFETY-NEXT:  var a: UnsafeMutableRawPointer!
+// BOUNDS-SAFETY-NEXT:  var b: UnsafeMutablePointer<Int32>!
+// BOUNDS-SAFETY-NEXT: }
+// BOUNDS-SAFETY-NEXT: func g(_: g) -> UnsafeMutablePointer<g>!
+// BOUNDS-SAFETY-NEXT: struct h {
+// BOUNDS-SAFETY-NEXT:  init()
+// BOUNDS-SAFETY-NEXT:  init(a: UnsafeMutableRawPointer!, b: UnsafeMutablePointer<Int32>!)
+// BOUNDS-SAFETY-NEXT:  var a: UnsafeMutableRawPointer!
+// BOUNDS-SAFETY-NEXT:  var b: UnsafeMutablePointer<Int32>!
+// BOUNDS-SAFETY-NEXT: }
+// BOUNDS-SAFETY-NEXT: func h(_: h) -> UnsafeMutablePointer<h>!
+
+// CHECK-NEXT: struct i {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   var len: Int{{[0-9]+}}
+// CHECK-NEXT: }
+// CHECK-NEXT: func i(_: UnsafeMutablePointer<i>!) -> UnsafeMutablePointer<i>!
+// CHECK-NEXT: var len1: Int{{[0-9]+}} { get }
+// CHECK-NEXT: struct j {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   init(a: UnsafeMutablePointer<Int{{[0-9]+}}>!, b: UnsafeMutableRawPointer!)
+// CHECK-NEXT:   var a: UnsafeMutablePointer<Int{{[0-9]+}}>!
+// CHECK-NEXT:   var b: UnsafeMutableRawPointer!
+// CHECK-NEXT: }
+// CHECK-NEXT: func j(_: j) -> UnsafeMutablePointer<j>!
+// CHECK-NEXT: var len2: Int{{[0-9]+}}
+// CHECK-NEXT: struct k {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   init(a: UnsafeMutablePointer<Int{{[0-9]+}}>!, b: UnsafeMutableRawPointer!)
+// CHECK-NEXT:   var a: UnsafeMutablePointer<Int{{[0-9]+}}>!
+// CHECK-NEXT:   var b: UnsafeMutableRawPointer!
+// CHECK-NEXT: }
+// CHECK-NEXT: func k(_: k) -> UnsafeMutablePointer<k>!
+
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -cxx-interoperability-mode=swift-6
+// RUN: %target-swift-frontend -Xcc -fbounds-safety -disable-objc-interop -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -D BOUNDS_SAFETY
+
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -verify -verify-additional-file %S/Inputs/bounds-attributed-struct.h -D VERIFY
+// RUN: %target-swift-frontend -Xcc -fexperimental-bounds-safety-attributes -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -cxx-interoperability-mode=swift-6 -verify -verify-additional-file %S/Inputs/bounds-attributed-struct.h -D VERIFY
+// RUN: %target-swift-frontend -Xcc -fbounds-safety -disable-objc-interop -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs %s -verify -verify-additional-file %S/Inputs/bounds-attributed-struct.h -D BOUNDS_SAFETY -D VERIFY
+
+import BoundsAttributedStruct
+
+func call(aa: a, bb: b, cc: c, dd: d, ee: e, ff: f, ii: UnsafeMutablePointer<i>, jj: j, kk: k, ll: l, mm: m) {
+    let _ = aa.a
+    let _ = a(aa)
+
+    let _ = bb.a
+    let _ = b(bb)
+
+    let _ = cc.a
+    let _ = c(cc)
+
+    let _ = dd.a
+    let _ = d(dd)
+
+    let _ = ee.a
+    let _ = e(ee)
+
+    let _ = ff.a
+    let _ = f(ff)
+
+    let _ = unsafe ii.pointee.len
+#if VERIFY
+    // rdar://152293598 ([ClangImporter] Importing global array errors on macOS and Linux, but not on Windows)
+    // XFAIL: OS=windows-msvc
+    // flexible array member not imported rdar://151665752
+    let _ = i.a // expected-error{{type 'i' has no member 'a'}}
+#endif
+    let _ = i(ii)
+
+    let _ = jj.a
+    let _ = jj.b
+    let _ = j(jj)
+
+    let _ = kk.a
+    let _ = kk.b
+    let _ = k(kk)
+
+    let _ = ll.a
+    let _ = ll.end
+    let _ = l(ll)
+
+    let _ = mm.a
+    let _ = mm.end
+    let _ = m(mm)
+}
+
+#if BOUNDS_SAFETY
+func boundsSafe(gg: g, hh: h) {
+    let _ = gg.a
+    let _ = gg.b
+    let _ = g(gg)
+
+    let _ = hh.a
+    let _ = hh.b
+    let _ = h(hh)
+}
+#endif
diff --git a/test/Interop/C/chars/Inputs/import-cchar-types.h b/test/Interop/C/chars/Inputs/import-cchar-types.h
index 466aafd567997..6c3600d2b5ced 100644
--- a/test/Interop/C/chars/Inputs/import-cchar-types.h
+++ b/test/Interop/C/chars/Inputs/import-cchar-types.h
@@ -6,6 +6,10 @@
 extern char a_char;
 extern wchar_t a_wchar;
 
+// This case is a regression test for a crash when importing constant initializers for wchar_t,
+// since Unicode.Scalar cannot be initialized with integer literals.
+const wchar_t an_initialized_wchar = 2;
+
 #if __cplusplus
 extern char8_t small_char;
 #endif
diff --git a/test/Interop/C/chars/import-cchar-types.swift b/test/Interop/C/chars/import-cchar-types.swift
index b5afdaf20fb9d..9ed50bd7d83c4 100644
--- a/test/Interop/C/chars/import-cchar-types.swift
+++ b/test/Interop/C/chars/import-cchar-types.swift
@@ -3,5 +3,6 @@
 
 // CHECK: var a_char: CChar
 // CHECK: var a_wchar: wchar_t
+// CHECK: var an_initialized_wchar: wchar_t { get }
 
 // CHECK-CXX: var small_char: UInt8
diff --git a/test/Interop/C/implementation-only-imports/check-function-visibility-inversed.swift b/test/Interop/C/implementation-only-imports/check-function-visibility-inversed.swift
index 974349324ea83..78df7f131a88c 100644
--- a/test/Interop/C/implementation-only-imports/check-function-visibility-inversed.swift
+++ b/test/Interop/C/implementation-only-imports/check-function-visibility-inversed.swift
@@ -11,7 +11,7 @@
 import UserA
 @_implementationOnly import UserB
 
-@_inlineable
+@inlinable
 public func callFortyTwo() -> CInt {
   return getFortyTwo()
 }
diff --git a/test/Interop/C/implementation-only-imports/check-function-visibility.swift b/test/Interop/C/implementation-only-imports/check-function-visibility.swift
index b427725e1e155..2f0a3c21f4b95 100644
--- a/test/Interop/C/implementation-only-imports/check-function-visibility.swift
+++ b/test/Interop/C/implementation-only-imports/check-function-visibility.swift
@@ -11,7 +11,7 @@
 @_implementationOnly import UserA
 import UserB
 
-@_inlineable
+@inlinable
 public func callFortyTwo() -> CInt {
   return getFortyTwo()
 }
diff --git a/test/Interop/C/struct/Inputs/NoncopyableStructs.apinotes b/test/Interop/C/struct/Inputs/NoncopyableStructs.apinotes
new file mode 100644
index 0000000000000..44bf09e74da51
--- /dev/null
+++ b/test/Interop/C/struct/Inputs/NoncopyableStructs.apinotes
@@ -0,0 +1,6 @@
+---
+Name: NoncopyableStructs
+Tags:
+- Name: NonCopyableWithAPINotesDeinit
+  SwiftCopyable: false
+  SwiftDestroyOp: freeNonCopyableWithAPINotesDeinit
diff --git a/test/Interop/C/struct/Inputs/StructAsOptionSet.apinotes b/test/Interop/C/struct/Inputs/StructAsOptionSet.apinotes
new file mode 100644
index 0000000000000..bf409b50f9945
--- /dev/null
+++ b/test/Interop/C/struct/Inputs/StructAsOptionSet.apinotes
@@ -0,0 +1,14 @@
+---
+Name: StructAsOptionSet
+Typedefs:
+- Name: WGPUBufferUsage
+  SwiftConformsTo: Swift.OptionSet
+  SwiftWrapper: struct
+Globals:
+- Name: WGPUBufferUsage_None
+  SwiftName: WGPUBufferUsage.none
+- Name: WGPUBufferUsage_MapRead
+  SwiftName: WGPUBufferUsage.mapRead
+- Name: WGPUBufferUsage_MapWrite
+  SwiftName: WGPUBufferUsage.mapWrite
+
diff --git a/test/Interop/C/struct/Inputs/foreign-reference-invalid.h b/test/Interop/C/struct/Inputs/foreign-reference-invalid.h
new file mode 100644
index 0000000000000..39a6b4fbc48ac
--- /dev/null
+++ b/test/Interop/C/struct/Inputs/foreign-reference-invalid.h
@@ -0,0 +1,20 @@
+#include <stdlib.h>
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:nonexistent")))
+__attribute__((swift_attr("release:nonexistent"))) NonExistent {
+  int value;
+};
+
+struct __attribute__((swift_attr("import_reference"))) NoRetainRelease {
+  int value;
+};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:badRetain")))
+__attribute__((swift_attr("release:badRelease"))) BadRetainRelease {
+  int value;
+};
+
+float badRetain(struct BadRetainRelease *v);
+void badRelease(struct BadRetainRelease *v, int i);
diff --git a/test/Interop/C/struct/Inputs/module.modulemap b/test/Interop/C/struct/Inputs/module.modulemap
index f227021cc75e2..339adb3139a14 100644
--- a/test/Interop/C/struct/Inputs/module.modulemap
+++ b/test/Interop/C/struct/Inputs/module.modulemap
@@ -5,4 +5,16 @@ module StructDeclContext {
 
 module ForeignReference {
   header "foreign-reference.h"
-}
\ No newline at end of file
+}
+
+module ForeignReferenceInvalid {
+  header "foreign-reference-invalid.h"
+}
+
+module StructAsOptionSet {
+  header "struct-as-option-set.h"
+}
+
+module NoncopyableStructs {
+  header "noncopyable-struct.h"
+}
diff --git a/test/Interop/C/struct/Inputs/noncopyable-struct.h b/test/Interop/C/struct/Inputs/noncopyable-struct.h
new file mode 100644
index 0000000000000..f815d5226a7e7
--- /dev/null
+++ b/test/Interop/C/struct/Inputs/noncopyable-struct.h
@@ -0,0 +1,56 @@
+#include "swift/bridging"
+
+typedef struct __attribute__((swift_attr("~Copyable"))) NonCopyable {
+  float x, y;
+} NonCopyable;
+
+typedef struct SWIFT_NONCOPYABLE_WITH_DESTROY(freeNonCopyableWithDeinit) NonCopyableWithDeinit {
+  void *storage;
+} NonCopyableWithDeinit;
+
+typedef struct NonCopyableWithAPINotesDeinit {
+  void *storage;
+} NonCopyableWithAPINotesDeinit;
+
+typedef struct __attribute__((swift_attr("destroy:freeCopyableType"))) CopyableType {
+  void *storage;
+} CopyableType;
+
+typedef struct __attribute__((swift_attr("~Copyable"))) __attribute__((swift_attr("destroy:freeMultiNonCopyable1"))) __attribute__((swift_attr("destroy:freeMultiNonCopyable2"))) MultiNonCopyableType {
+  void *storage;
+} MultiNonCopyableType;
+
+typedef struct __attribute__((swift_attr("~Copyable"))) __attribute__((swift_attr("destroy:badDestroy1"))) BadDestroyNonCopyableType {
+  void *storage;
+} BadDestroyNonCopyableType;
+
+typedef struct __attribute__((swift_attr("~Copyable"))) __attribute__((swift_attr("destroy:badDestroy2"))) BadDestroyNonCopyableType2 {
+  void *storage;
+} BadDestroyNonCopyableType2;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void freeNonCopyableWithDeinit(NonCopyableWithDeinit ncd);
+void freeNonCopyableWithAPINotesDeinit(NonCopyableWithAPINotesDeinit ncd);
+void freeCopyableType(CopyableType ct);
+
+
+void freeMultiNonCopyable1(MultiNonCopyableType ct);
+void freeMultiNonCopyable2(MultiNonCopyableType ct);
+
+void badDestroy1(void);
+void badDestroy2(BadDestroyNonCopyableType2 *ptr);
+
+#ifdef __cplusplus
+
+struct __attribute__((swift_attr("~Copyable"))) __attribute__((swift_attr("destroy:extraDestroy"))) ExtraDestroy {
+  void *storage;
+  ExtraDestroy(ExtraDestroy&&) = default;
+  ~ExtraDestroy() { }
+};
+
+void extraDestroy(ExtraDestroy);
+}
+#endif
diff --git a/test/Interop/C/struct/Inputs/struct-as-option-set.h b/test/Interop/C/struct/Inputs/struct-as-option-set.h
new file mode 100644
index 0000000000000..bb50e36b51b2e
--- /dev/null
+++ b/test/Interop/C/struct/Inputs/struct-as-option-set.h
@@ -0,0 +1,6 @@
+#include <stdint.h>
+
+typedef uint32_t WGPUBufferUsage;
+static const WGPUBufferUsage WGPUBufferUsage_None = 0x0000000000000000;
+static const WGPUBufferUsage WGPUBufferUsage_MapRead = 0x0000000000000001;
+static const WGPUBufferUsage WGPUBufferUsage_MapWrite = 0x0000000000000002;
diff --git a/test/Interop/C/struct/foreign-reference-flag-deprecated.swift b/test/Interop/C/struct/foreign-reference-flag-deprecated.swift
new file mode 100644
index 0000000000000..7c9398e51bdd2
--- /dev/null
+++ b/test/Interop/C/struct/foreign-reference-flag-deprecated.swift
@@ -0,0 +1,5 @@
+// RUN: %target-build-swift %s -I %S/Inputs/ -Xfrontend -experimental-c-foreign-reference-types 2>&1 | %FileCheck %s
+
+// CHECK: <unknown>:0: warning: flag '-experimental-c-foreign-reference-types' is deprecated
+
+import ForeignReference
diff --git a/test/Interop/C/struct/foreign-reference-invalid-typechecker.swift b/test/Interop/C/struct/foreign-reference-invalid-typechecker.swift
new file mode 100644
index 0000000000000..9717c614ed4b0
--- /dev/null
+++ b/test/Interop/C/struct/foreign-reference-invalid-typechecker.swift
@@ -0,0 +1,15 @@
+// RUN: not %target-swift-frontend -typecheck %s -I %S/Inputs -disable-availability-checking -diagnostic-style llvm 2>&1 | %FileCheck %s
+
+import ForeignReferenceInvalid
+
+// CHECK: error: cannot find retain function 'nonexistent' for reference type 'NonExistent'
+// CHECK: error: cannot find release function 'nonexistent' for reference type 'NonExistent'
+public func test(x: NonExistent) { }
+
+// CHECK: error: reference type 'NoRetainRelease' must have 'retain:' Swift attribute
+// CHECK: error: reference type 'NoRetainRelease' must have 'release:' Swift attribute
+public func test(x: NoRetainRelease) { }
+
+// CHECK: error: specified retain function 'badRetain' is invalid; retain function must either return have 'void', the reference count as an integer, or the parameter type
+// CHECK: error: specified release function 'badRelease' is invalid; release function must have exactly one argument of type 'BadRetainRelease'
+public func test(x: BadRetainRelease) { }
diff --git a/test/Interop/C/struct/foreign-reference.swift b/test/Interop/C/struct/foreign-reference.swift
index 43680cd995f1f..9c30d27f3b230 100644
--- a/test/Interop/C/struct/foreign-reference.swift
+++ b/test/Interop/C/struct/foreign-reference.swift
@@ -1,9 +1,7 @@
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -validate-tbd-against-ir=none -Xfrontend -experimental-c-foreign-reference-types -Onone -D NO_OPTIMIZATIONS)
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -validate-tbd-against-ir=none -Xfrontend -experimental-c-foreign-reference-types -O)
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -validate-tbd-against-ir=none -Onone -D NO_OPTIMIZATIONS)
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -validate-tbd-against-ir=none -O)
 //
 // REQUIRES: executable_test
-// TODO: This should work without ObjC interop in the future rdar://97497120
-// REQUIRES: objc_interop
 
 import StdlibUnittest
 import ForeignReference
diff --git a/test/Interop/C/struct/noncopyable_structs.swift b/test/Interop/C/struct/noncopyable_structs.swift
new file mode 100644
index 0000000000000..e20c2e04c1184
--- /dev/null
+++ b/test/Interop/C/struct/noncopyable_structs.swift
@@ -0,0 +1,86 @@
+// Check that we get the expected errors for incorrect uses of noncopyable
+// imported types with both C and C++ interoperability.
+
+// RUN: %target-swift-frontend -emit-sil -I %S/Inputs/ -I %swift_src_root/lib/ClangImporter/SwiftBridging %s -verify -DERRORS -verify-additional-prefix conly-
+// RUN: %target-swift-frontend -emit-sil -I %S/Inputs/ -I %swift_src_root/lib/ClangImporter/SwiftBridging %s -verify -DERRORS -DCPLUSPLUS -verify-additional-prefix cplusplus- -cxx-interoperability-mode=default
+
+// Check that we get the expected SIL
+// RUN: %target-swift-frontend -emit-sil -I %S/Inputs/ -I %swift_src_root/lib/ClangImporter/SwiftBridging %s -o - | %FileCheck -check-prefix CHECK-SIL %s
+// RUN: %target-swift-frontend -emit-sil -I %S/Inputs/ -I %swift_src_root/lib/ClangImporter/SwiftBridging %s -o - -cxx-interoperability-mode=default| %FileCheck  -check-prefix CHECK-SIL %s
+
+// Check that we get the expected IR
+
+// RUN: %target-swift-frontend -emit-ir -I %S/Inputs/ -I %swift_src_root/lib/ClangImporter/SwiftBridging %s -o - | %FileCheck -check-prefix CHECK-IR %s
+// RUN: %target-swift-frontend -emit-ir -I %S/Inputs/ -I %swift_src_root/lib/ClangImporter/SwiftBridging %s -o - -cxx-interoperability-mode=default | %FileCheck -check-prefix CHECK-IR %s
+
+import NoncopyableStructs
+
+// CHECK-IR-LABEL: define hidden swiftcc void @"$s19noncopyable_structs9consumeNCyySo11NonCopyableVnF"(float %0, float %1) #0 {
+// CHECK-IR: call ptr @"$sSo11NonCopyableVWOh"
+// CHECK-IR: define linkonce_odr hidden ptr @"$sSo11NonCopyableVWOh"(ptr %0)
+// CHECK-IR-NEXT: entry:
+// CHECK-IR-NEXT: ret ptr
+func consumeNC(_ nc: consuming NonCopyable) { }
+
+func testNC() {
+  let nc = NonCopyable() // expected-error{{'nc' consumed more than once}}
+  consumeNC(nc) // expected-note{{consumed here}}
+
+  let ncAPI = NonCopyableWithAPINotesDeinit() // expected-error{{consumed more than once}}
+  consumeNCAPI(ncAPI) // expected-note{{consumed here}}
+
+  #if ERRORS
+  consumeNC(nc) // expected-note{{consumed again here}}
+  consumeNCAPI(ncAPI) // expected-note{{consumed again here}}
+  #endif
+}
+
+func consumeNCAPI(_ nc: consuming NonCopyableWithAPINotesDeinit) { }
+
+func consumeNCWithDeinit(_ nc: consuming NonCopyableWithDeinit) { }
+
+func testNCWithDeinit() {
+  let nc = NonCopyableWithDeinit() // expected-error{{'nc' consumed more than once}}
+  consumeNCWithDeinit(nc) // expected-note{{consumed here}}
+
+  #if ERRORS
+  consumeNCWithDeinit(nc) // expected-note{{consumed again here}}
+  #endif
+}
+
+#if ERRORS
+// expected-warning@+1{{destroy operation 'freeCopyableType' is only allowed on non-copyable types; did you mean to use SWIFT_NONCOPYABLE?}}
+func copyableType(_: CopyableType) { }
+
+// expected-warning@+1{{'MultiNonCopyableType' is deprecated: multiple destroy operations ('freeMultiNonCopyable1' and 'freeMultiNonCopyable2') provided for type}}
+func multiNonCopyableType(_: borrowing MultiNonCopyableType) { }
+
+// expected-warning@+1{{'BadDestroyNonCopyableType' is deprecated: destroy function 'badDestroy1' must have a single parameter with type 'BadDestroyNonCopyableType'}}
+func bad1(_: borrowing BadDestroyNonCopyableType) { }
+
+// expected-warning@+1{{'BadDestroyNonCopyableType2' is deprecated: destroy function 'badDestroy2' must have a single parameter with type 'BadDestroyNonCopyableType2'}}
+func bad2(_: borrowing BadDestroyNonCopyableType2) { }
+
+#endif
+
+#if CPLUSPLUS
+// expected-cplusplus-warning@+1{{'ExtraDestroy' is deprecated: destroy operation 'extraDestroy' is not allowed on types with a non-trivial destructor}}
+func extra(_: borrowing ExtraDestroy) { }
+#endif
+
+// CHECK-SIL: sil shared @$sSo21NonCopyableWithDeinitVfD : $@convention(method) (@owned NonCopyableWithDeinit) -> () {
+// CHECK-SIL: bb0([[SELF:%[0-9]+]] : $NonCopyableWithDeinit):
+// CHECK-SIL: [[SELF_ALLOC:%[0-9]+]] = alloc_stack $NonCopyableWithDeinit
+// CHECK-SIL:  store [[SELF]] to [[SELF_ALLOC]]
+// CHECK-SIL: [[SELF_RELOAD:%[0-9]+]] = load [[SELF_ALLOC]]
+// CHECK-SIL: [[FN:%[0-9]+]] = function_ref @{{.*}}freeNonCopyableWithDeinit{{.*}} : $@convention(c) (NonCopyableWithDeinit) -> ()
+// CHECK-SIL:  apply [[FN]]([[SELF_RELOAD]]) : $@convention(c) (NonCopyableWithDeinit) -> ()
+
+// CHECK-IR-LABEL: define hidden swiftcc void @"$s19noncopyable_structs19consumeNCWithDeinityySo015NonCopyableWithE0VnF"
+// CHECK-IR: call swiftcc void @"$sSo21NonCopyableWithDeinitVfD"
+
+// CHECK-IR-LABEL: define {{.*}} swiftcc void @"$sSo21NonCopyableWithDeinitVfD"
+// CHECK-IR: {{(call|invoke)}} void @{{.*}}freeNonCopyableWithDeinit
+
+// CHECK-SIL-LABEL: sil_moveonlydeinit NonCopyableWithDeinit {
+// CHECK-SIL: @$sSo21NonCopyableWithDeinitVfD
diff --git a/test/Interop/C/struct/typedef_option_set.swift b/test/Interop/C/struct/typedef_option_set.swift
new file mode 100644
index 0000000000000..12f2b3fdc1361
--- /dev/null
+++ b/test/Interop/C/struct/typedef_option_set.swift
@@ -0,0 +1,10 @@
+// RUN: %target-typecheck-verify-swift -I %S/Inputs/
+
+import StructAsOptionSet
+
+func takeOptionSet<T: OptionSet>(_: T) { }
+
+func useStructAsOptionSet() {
+  let usage: WGPUBufferUsage = [.mapRead, .mapWrite]
+  takeOptionSet(usage)
+}
diff --git a/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-a.h b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-a.h
new file mode 100644
index 0000000000000..e31c04ac38ae6
--- /dev/null
+++ b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-a.h
@@ -0,0 +1,3 @@
+#pragma once
+
+typedef int a_t;
diff --git a/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-b.h b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-b.h
new file mode 100644
index 0000000000000..cdcb5f790ced2
--- /dev/null
+++ b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-b.h
@@ -0,0 +1,3 @@
+#pragma once
+
+typedef int b_t;
diff --git a/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-c.h b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-c.h
new file mode 100644
index 0000000000000..a00fe419e07cd
--- /dev/null
+++ b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-c.h
@@ -0,0 +1,2 @@
+#pragma once
+typedef int c_t;
diff --git a/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-d.h b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-d.h
new file mode 100644
index 0000000000000..91d0254316dfc
--- /dev/null
+++ b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-d.h
@@ -0,0 +1,2 @@
+#pragma once
+typedef int d_t;
diff --git a/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-e.h b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-e.h
new file mode 100644
index 0000000000000..eac3d7ddcac46
--- /dev/null
+++ b/test/Interop/C/swiftify-import/Inputs/TransitiveModules/module-e.h
@@ -0,0 +1,2 @@
+#pragma once
+typedef int e_t;
diff --git a/test/Interop/C/swiftify-import/Inputs/clang-includes.h b/test/Interop/C/swiftify-import/Inputs/clang-includes.h
new file mode 100644
index 0000000000000..096a824680724
--- /dev/null
+++ b/test/Interop/C/swiftify-import/Inputs/clang-includes.h
@@ -0,0 +1,20 @@
+#pragma once
+
+#include "TransitiveModules/module-a.h"
+#include "TransitiveModules/module-b.h"
+#include "TransitiveModules/module-c.h"
+#include "TransitiveModules/module-d.h"
+#include "TransitiveModules/module-e.h"
+
+#define __counted_by(x) __attribute__((__counted_by__(x)))
+#define __noescape __attribute__((noescape))
+
+void basic_include(const a_t *__counted_by(len) p __noescape, a_t len);
+
+void non_exported_include(const b_t *__counted_by(len) p __noescape, b_t len);
+
+void submodule_include(const c_t *__counted_by(len) p __noescape, c_t len);
+
+void explicit_submodule_include(const d_t *__counted_by(len) p __noescape, d_t len);
+
+void deep_submodule_noexport(const e_t *__counted_by(len) p __noescape, e_t len);
diff --git a/test/Interop/C/swiftify-import/Inputs/comments.h b/test/Interop/C/swiftify-import/Inputs/comments.h
new file mode 100644
index 0000000000000..900e240b070ef
--- /dev/null
+++ b/test/Interop/C/swiftify-import/Inputs/comments.h
@@ -0,0 +1,30 @@
+#pragma once
+
+#define __counted_by(x) __attribute__((__counted_by__(x)))
+
+void begin();
+
+// line comment
+void lineComment(int len, int * __counted_by(len) p);
+
+/// line doc comment
+/// 
+/// Here's a more complete description.
+///
+/// @param len the buffer length
+/// @param p the buffer
+void lineDocComment(int len, int * __counted_by(len) p);
+
+/*
+ block comment
+ */
+void blockComment(int len, int * __counted_by(len) p);
+
+/**
+ * block doc comment
+ * 
+ * NB: it's very important to pass the correct length to this function
+ * @param len don't mess this one up
+ * @param p   some integers to play with
+ */
+void blockDocComment(int len, int * __counted_by(len) p);
diff --git a/test/Interop/C/swiftify-import/Inputs/counted-by-lifetimebound.h b/test/Interop/C/swiftify-import/Inputs/counted-by-lifetimebound.h
new file mode 100644
index 0000000000000..6a5bbf2ee5534
--- /dev/null
+++ b/test/Interop/C/swiftify-import/Inputs/counted-by-lifetimebound.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#define __counted_by(x) __attribute__((__counted_by__(x)))
+#define __counted_by_or_null(x) __attribute__((__counted_by_or_null__(x)))
+#define __lifetimebound __attribute__((lifetimebound))
+
+int * __counted_by(len) simple(int len, int len2, int * p __counted_by(len2) __lifetimebound);
+
+int * __counted_by(len) shared(int len, int * p __counted_by(len) __lifetimebound);
+
+int * __counted_by(len - offset) complexExpr(int len, int offset, int len2, int * p __counted_by(len2) __lifetimebound);
+
+int * __counted_by(len) _Null_unspecified nullUnspecified(int len, int len2, int * _Null_unspecified p __counted_by(len2) __lifetimebound);
+
+int * __counted_by(len) _Nonnull nonnull(int len, int len2, int * _Nonnull p __counted_by(len2) __lifetimebound);
+
+int * __counted_by(len) _Nullable nullable(int len, int len2, int * _Nullable p __counted_by(len2) __lifetimebound);
+
+typedef struct foo opaque_t;
+opaque_t * __counted_by(len) opaque(int len, int len2, opaque_t * p __counted_by(len2) __lifetimebound);
+
+int * __counted_by(len) noncountedLifetime(int len, int * p __lifetimebound);
+
+int * __counted_by(13) _Nullable constant(int * _Nullable p __counted_by_or_null(13) __lifetimebound);
diff --git a/test/Interop/C/swiftify-import/Inputs/counted-by-noescape.h b/test/Interop/C/swiftify-import/Inputs/counted-by-noescape.h
index 6ea131586ac7a..0a02550614762 100644
--- a/test/Interop/C/swiftify-import/Inputs/counted-by-noescape.h
+++ b/test/Interop/C/swiftify-import/Inputs/counted-by-noescape.h
@@ -7,7 +7,7 @@
 void simple(int len, int * __counted_by(len) __noescape p);
 
 void swiftAttr(int len, int *p) __attribute__((
-    swift_attr("@_SwiftifyImport(.countedBy(pointer: .param(2), count: \"len\"), .nonescaping(pointer: .param(2)))")));
+    swift_attr("@_SwiftifyImport(.countedBy(pointer: .param(2), count: \"len\"), .nonescaping(pointer: .param(2)), spanAvailability: \"visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4\")")));
 
 void shared(int len, int * __counted_by(len) __noescape p1, int * __counted_by(len) __noescape p2);
 
@@ -17,8 +17,65 @@ void nullUnspecified(int len, int * __counted_by(len) _Null_unspecified __noesca
 
 void nonnull(int len, int * __counted_by(len) _Nonnull __noescape p);
 
-//void nullable(int len, int * __counted_by(len) _Nullable p);
+void nullable(int len, int * __counted_by(len) _Nullable p __noescape);
 
 int * __counted_by(len) __noescape returnPointer(int len);
 
 int * __counted_by(len1) returnLifetimeBound(int len1, int len2, int * __counted_by(len2) p __lifetimebound);
+
+void anonymous(int len, int * __counted_by(len) _Nullable __noescape);
+
+void keyword(int len, int * __counted_by(len) _Nullable func __noescape,
+    int extension,
+    int init,
+    int open,
+    int var,
+    int is,
+    int as,
+    int in,
+    int guard,
+    int where
+);
+
+void pointerName(int len, int * __counted_by(len) _Nullable pointerName __noescape);
+
+void lenName(int lenName, int size, int * __counted_by(lenName * size) _Nullable p __noescape);
+
+void func(int len, int * __counted_by(len) _Nullable func __noescape);
+
+void *funcRenameKeyword(int len, int * __counted_by(len) _Nullable func __noescape,
+    int extension,
+    int init,
+    int open,
+    int var,
+    int is,
+    int as,
+    int in,
+    int guard,
+    int where) __attribute__((swift_name("funcRenamed(len:func:extension:init:open:var:is:as:in:guard:where:)")));
+
+void *funcRenameKeywordAnonymous(int len, int * __counted_by(len) _Nullable __noescape,
+    int,
+    int,
+    int,
+    int,
+    int,
+    int,
+    int,
+    int,
+    int) __attribute__((swift_name("funcRenamedAnon(len:func:extension:init:open:var:is:as:in:guard:where:)")));
+
+void funcRenameClash(int len, int * __counted_by(len) _Nullable func __noescape, int where)
+    __attribute__((swift_name("clash(len:func:clash:)")));
+
+void funcRenameClashKeyword(int len, int * __counted_by(len) _Nullable func __noescape, int where)
+    __attribute__((swift_name("open(len:func:open:)")));
+
+void funcRenameClashAnonymous(int len, int * __counted_by(len) _Nullable func __noescape, int)
+    __attribute__((swift_name("clash2(len:func:clash2:)")));
+
+void funcRenameClashKeywordAnonymous(int len, int * __counted_by(len) _Nullable func __noescape, int)
+    __attribute__((swift_name("in(len:func:in:)")));
+
+typedef struct actor_ *actor;
+actor _Nonnull keywordType(int len, actor * __counted_by(len) __noescape p, actor _Nonnull p2);
diff --git a/test/Interop/C/swiftify-import/Inputs/counted-by.h b/test/Interop/C/swiftify-import/Inputs/counted-by.h
index 4765553c6559a..2b855eeffc430 100644
--- a/test/Interop/C/swiftify-import/Inputs/counted-by.h
+++ b/test/Interop/C/swiftify-import/Inputs/counted-by.h
@@ -4,6 +4,8 @@
 
 void simple(int len, int * __counted_by(len) p);
 
+void simpleFlipped(int * __counted_by(len) p, int len);
+
 void swiftAttr(int len, int *p) __attribute__((
     swift_attr("@_SwiftifyImport(.countedBy(pointer: .param(2), count: \"len\"))")));
 
@@ -18,3 +20,45 @@ void nonnull(int len, int * __counted_by(len) _Nonnull p);
 void nullable(int len, int * __counted_by(len) _Nullable p);
 
 int * __counted_by(len) returnPointer(int len);
+
+void offByOne(int len, int * __counted_by(len + 1) p);
+
+void offBySome(int len, int offset, int * __counted_by(len + (1 + offset)) p);
+
+void scalar(int m, int n, int * __counted_by(m * n) p);
+
+void bitwise(int m, int n, int o, int * __counted_by(m & n | ~o) p);
+
+void bitshift(int m, int n, int o, int * __counted_by(m << (n >> o)) p);
+
+void constInt(int * __counted_by(42 * 10) p);
+
+void constFloatCastedToInt(int * __counted_by((int) (4.2 / 12)) p);
+
+void sizeofType(int * __counted_by(sizeof(int *)) p);
+
+void sizeofParam(int * __counted_by(sizeof(p)) p);
+
+void derefLen(int * len, int * __counted_by(*len) p);
+
+void lNot(int len, int * __counted_by(!len) p);
+
+void lAnd(int len, int * __counted_by(len && len) p);
+
+void lOr(int len, int * __counted_by(len || len) p);
+
+void floatCastToInt(float meters, int * __counted_by((int) meters) p);
+
+void pointerCastToInt(int *square, int * __counted_by((int) square) p);
+
+void nanAsInt(int * __counted_by((int) (0 / 0)) p);
+
+void unsignedLiteral(int * __counted_by(2u) p);
+
+void longLiteral(int * __counted_by(2l) p);
+
+void hexLiteral(int * __counted_by(0xfa) p);
+
+void binaryLiteral(int * __counted_by(0b10) p);
+
+void octalLiteral(int * __counted_by(0777) p);
diff --git a/test/Interop/C/swiftify-import/Inputs/module.modulemap b/test/Interop/C/swiftify-import/Inputs/module.modulemap
index 896f9f1832d0a..29c1c6b295413 100644
--- a/test/Interop/C/swiftify-import/Inputs/module.modulemap
+++ b/test/Interop/C/swiftify-import/Inputs/module.modulemap
@@ -14,4 +14,48 @@ module SizedByNoEscapeClang {
     header "sized-by-noescape.h"
     export *
 }
+module SizedByLifetimeboundClang {
+    header "sized-by-lifetimebound.h"
+    export *
+}
+module CountedByLifetimeboundClang {
+    header "counted-by-lifetimebound.h"
+    export *
+}
+module CommentsClang {
+    header "comments.h"
+    export *
+}
+module ClangIncludesModule {
+    header "clang-includes.h"
+    export *
+}
+module ClangIncludesNoExportModule {
+    header "clang-includes.h"
+}
 
+// TransitiveModules/
+module ModuleA {
+    header "TransitiveModules/module-a.h"
+    export *
+}
+module ModuleB {
+    header "TransitiveModules/module-b.h"
+}
+module ModuleOuter {
+    module ModuleC {
+        header "TransitiveModules/module-c.h"
+        export *
+    }
+    explicit module ModuleD {
+         header "TransitiveModules/module-d.h"
+         export *
+    }
+}
+module ModuleDeep {
+    module ModuleDeepNested {
+        module ModuleDeepNestedNested {
+            header "TransitiveModules/module-e.h"
+        }
+    }
+}
diff --git a/test/Interop/C/swiftify-import/Inputs/sized-by-lifetimebound.h b/test/Interop/C/swiftify-import/Inputs/sized-by-lifetimebound.h
new file mode 100644
index 0000000000000..e66f2fa1ee80c
--- /dev/null
+++ b/test/Interop/C/swiftify-import/Inputs/sized-by-lifetimebound.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifndef __sized_by
+#define __sized_by(x) __attribute__((__sized_by__(x)))
+#endif
+#define __lifetimebound __attribute__((lifetimebound))
+
+const void * __sized_by(len) simple(int len, int len2, const void * p __sized_by(len2) __lifetimebound);
+
+const void * __sized_by(len) shared(int len, const void * p __sized_by(len) __lifetimebound);
+
+const void * __sized_by(len - offset) complexExpr(int len, int offset, int len2, const void * p __sized_by(len2) __lifetimebound);
+
+const void * __sized_by(len) _Null_unspecified nullUnspecified(int len, int len2, const void * _Null_unspecified p __sized_by(len2) __lifetimebound);
+
+const void * __sized_by(len) _Nonnull nonnull(int len, int len2, const void * _Nonnull p __sized_by(len2) __lifetimebound);
+
+const void * __sized_by(len) _Nullable nullable(int len, int len2, const void * _Nullable p __sized_by(len2) __lifetimebound);
+
+typedef struct foo opaque_t;
+opaque_t * __sized_by(len) opaque(int len, int len2, opaque_t * p __sized_by(len2) __lifetimebound);
+
+const void * __sized_by(len) nonsizedLifetime(int len, const void * p __lifetimebound);
+
+uint8_t *__sized_by(size)  bytesized(int size, const uint8_t * p __sized_by(size) __lifetimebound);
+
+char *__sized_by(size) charsized(char * p __sized_by(size) __lifetimebound, int size);
+
+const uint16_t *__sized_by(size)  doublebytesized(uint16_t * p __sized_by(size) __lifetimebound, int size);
diff --git a/test/Interop/C/swiftify-import/Inputs/sized-by-noescape.h b/test/Interop/C/swiftify-import/Inputs/sized-by-noescape.h
index 7d18654569046..8105ed9764367 100644
--- a/test/Interop/C/swiftify-import/Inputs/sized-by-noescape.h
+++ b/test/Interop/C/swiftify-import/Inputs/sized-by-noescape.h
@@ -1,12 +1,16 @@
 #pragma once
 
+#include <stdint.h>
+
+#ifndef __sized_by
 #define __sized_by(x) __attribute__((__sized_by__(x)))
+#endif
 #define __noescape __attribute__((noescape))
 
 void simple(int len, const void * __sized_by(len) __noescape p);
 
 void swiftAttr(int len, const void *p) __attribute__((swift_attr(
-    "@_SwiftifyImport(.sizedBy(pointer: .param(2), size: \"len\"), .nonescaping(pointer: .param(2)))")));
+    "@_SwiftifyImport(.sizedBy(pointer: .param(2), size: \"len\"), .nonescaping(pointer: .param(2)), spanAvailability: \"visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4\")")));
 
 void shared(int len, const void * __sized_by(len) __noescape p1, const void * __sized_by(len) __noescape p2);
 
@@ -16,11 +20,15 @@ void nullUnspecified(int len, const void * __sized_by(len) __noescape _Null_unsp
 
 void nonnull(int len, const void * __sized_by(len) __noescape _Nonnull p);
 
-// Nullable ~Escapable types not supported yet
-//void nullable(int len, const void * __sized_by(len) __noescape _Nullable p);
+void nullable(int len, const void * __sized_by(len) __noescape _Nullable p);
 
 const void * __sized_by(len) __noescape _Nonnull returnPointer(int len);
 
 typedef struct foo opaque_t;
 void opaque(int len, opaque_t * __sized_by(len) __noescape p);
 
+void bytesized(int size, const uint8_t *__sized_by(size) __noescape);
+
+void charsized(char *__sized_by(size) __noescape, int size);
+
+void doublebytesized(uint16_t *__sized_by(size) __noescape, int size);
diff --git a/test/Interop/C/swiftify-import/Inputs/sized-by.h b/test/Interop/C/swiftify-import/Inputs/sized-by.h
index 9f5daad61dbca..9a6e95f5dbeef 100644
--- a/test/Interop/C/swiftify-import/Inputs/sized-by.h
+++ b/test/Interop/C/swiftify-import/Inputs/sized-by.h
@@ -1,6 +1,10 @@
 #pragma once
 
+#include <stdint.h>
+
+#ifndef __sized_by
 #define __sized_by(x) __attribute__((__sized_by__(x)))
+#endif
 
 void simple(int len, void * __sized_by(len) p);
 
@@ -21,3 +25,15 @@ void * __sized_by(len) returnPointer(int len);
 
 typedef struct foo opaque_t;
 void opaque(int len, opaque_t * __sized_by(len) p);
+
+typedef opaque_t *opaqueptr_t;
+void opaqueptr(int len, opaqueptr_t __sized_by(len) p);
+
+void charsized(char *__sized_by(size), int size);
+
+uint8_t *__sized_by(size) bytesized(int size);
+
+void doublebytesized(uint16_t *__sized_by(size), int size);
+
+typedef uint8_t * bytesizedptr_t;
+void aliasedBytesized(bytesizedptr_t __sized_by(size) p, int size);
diff --git a/test/Interop/C/swiftify-import/clang-includes-aliasing-imports.swift b/test/Interop/C/swiftify-import/clang-includes-aliasing-imports.swift
new file mode 100644
index 0000000000000..13588c6d76abd
--- /dev/null
+++ b/test/Interop/C/swiftify-import/clang-includes-aliasing-imports.swift
@@ -0,0 +1,135 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -dump-source-file-imports -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift 2>&1 | %FileCheck %s --check-prefix DUMP
+// RUN: %target-swift-frontend -dump-source-file-imports -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift -cxx-interoperability-mode=default 2>&1 | %FileCheck %s --check-prefix DUMP --check-prefix DUMP-CXX
+
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-A1 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A2 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-A2 --implicit-check-not=import --match-full-lines
+
+//--- test.swift
+import A1
+
+import A2
+
+// DUMP: imports for {{.*}}/test.swift:
+// DUMP-NEXT:   Swift
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   A2
+
+public func callUnsafe(_ p: UnsafeMutableRawPointer) {
+  let _ = a1(p, 13)
+  let _ = a2(p, 13)
+}
+
+public func callSafe(_ p: UnsafeMutableRawBufferPointer) {
+  let _ = a1(p)
+  let _ = a2(p)
+}
+
+//--- Inputs/module.modulemap
+module A1 {
+  header "A1.h"
+  explicit module Aliasing {
+    // Make sure that the full module path is taken into account
+    // and not just the module name
+    header "Aliasing1.h"
+    explicit module Aliasing {
+      header "Aliasing2.h"
+    }
+  }
+}
+module A2 {
+  header "A2.h"
+}
+module A3 {
+  explicit module Aliasing {
+    header "Aliasing3.h"
+  }
+}
+module A4 {
+  explicit module Aliasing {
+    header "Aliasing4.h"
+  }
+}
+
+//--- Inputs/A1.h
+#pragma once
+
+#include "Aliasing1.h"
+#include "Aliasing2.h"
+
+// CHECK-A1: import A1.Aliasing
+// CHECK-A1: import A1.Aliasing.Aliasing
+
+#define __sized_by(s) __attribute__((__sized_by__(s)))
+
+aliasing1_t a1(void * _Nonnull __sized_by(size), aliasing2_t size);
+
+// DUMP-NEXT: imports for A1.a1:
+// DUMP-NEXT: imports for @__swiftmacro_So2a115_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   Aliasing
+// DUMP-NEXT:   Aliasing
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/Aliasing1.h
+#pragma once
+
+typedef int aliasing1_t;
+
+//--- Inputs/Aliasing2.h
+#pragma once
+
+typedef int aliasing2_t;
+
+//--- Inputs/Aliasing3.h
+#pragma once
+
+typedef int aliasing3_t;
+
+//--- Inputs/Aliasing4.h
+#pragma once
+
+typedef int aliasing4_t;
+
+//--- Inputs/A2.h
+#pragma once
+
+#include "Aliasing3.h"
+#include "Aliasing4.h"
+
+// CHECK-A2-NOT: import
+
+#define __sized_by(s) __attribute__((__sized_by__(s)))
+
+aliasing3_t a2(void * _Nonnull __sized_by(size), aliasing4_t size);
+
+// DUMP-NEXT: imports for A2.a2:
+// DUMP-NEXT: imports for @__swiftmacro_So2a215_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   Aliasing
+// DUMP-NEXT:   A4
+// DUMP-NEXT:   Aliasing
+// DUMP-NEXT:   A3
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+// DUMP-NOT: imports
diff --git a/test/Interop/C/swiftify-import/clang-includes-explicit.swift b/test/Interop/C/swiftify-import/clang-includes-explicit.swift
new file mode 100644
index 0000000000000..9e87ae1fa04e5
--- /dev/null
+++ b/test/Interop/C/swiftify-import/clang-includes-explicit.swift
@@ -0,0 +1,58 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift -cxx-interoperability-mode=default
+
+//--- test.swift
+import A1.B1.C1.D1
+
+public func callUnsafe(_ p: UnsafeMutableRawPointer) {
+  let _ = foo(p, 13)
+}
+
+public func callSafe(_ p: UnsafeMutableRawBufferPointer) {
+  let _ = foo(p)
+}
+
+//--- Inputs/module.modulemap
+module A1 {
+  explicit module B1 {
+    explicit module C1 {
+      explicit module D1 {
+        header "D1.h"
+      }
+    }
+  }
+}
+
+module A2 {
+ explicit module B2 {
+    header "B2.h"
+    export C2
+
+    explicit module C2 {
+      header "C2.h"
+    }
+  }
+}
+
+//--- Inputs/D1.h
+#pragma once
+
+#include "B2.h"
+#define __sized_by(s) __attribute__((__sized_by__(s)))
+
+c2_t foo(void * _Nonnull __sized_by(size), int size);
+
+//--- Inputs/B2.h
+#pragma once
+
+#include "C2.h"
+
+//--- Inputs/C2.h
+#pragma once
+
+typedef int c2_t;
diff --git a/test/Interop/C/swiftify-import/clang-includes-indirect-explicit-modules.swift b/test/Interop/C/swiftify-import/clang-includes-indirect-explicit-modules.swift
new file mode 100644
index 0000000000000..35a934ec4d2a8
--- /dev/null
+++ b/test/Interop/C/swiftify-import/clang-includes-indirect-explicit-modules.swift
@@ -0,0 +1,195 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -dump-source-file-imports -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift 2>&1 | %FileCheck %s --check-prefix DUMP
+// RUN: %target-swift-frontend -dump-source-file-imports -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift -cxx-interoperability-mode=default 2>&1 | %FileCheck %s --check-prefix DUMP --check-prefix DUMP-CXX
+
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1.B1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-B1 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1.B1.C1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-C1 --implicit-check-not=import --match-full-lines
+
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A2.B2 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-B2 --implicit-check-not=import --match-full-lines
+
+//--- test.swift
+import A1.B1
+import A2.B2
+
+// DUMP: imports for {{.*}}/test.swift:
+// DUMP-NEXT:   Swift
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   B2
+// DUMP-NEXT:   A2
+
+public func callUnsafe(_ p: UnsafeMutableRawPointer) {
+  let _ = b1b(p, 13)
+  let _ = b1c(p, 13)
+  let _ = b1d(p, 13)
+  let _ = b2b(p, 13)
+  let _ = b2c(p, 13)
+  let _ = b2d(p, 13)
+}
+
+public func callSafe(_ p: UnsafeMutableRawBufferPointer) {
+  let _ = b1b(p)
+  let _ = b1c(p)
+  let _ = b1d(p)
+  let _ = b2b(p)
+  let _ = b2c(p)
+  let _ = b2d(p)
+}
+//--- Inputs/module.modulemap
+module A1 {
+  explicit module B1 {
+    header "B1.h"
+    explicit module C1 {
+      header "C1.h"
+      explicit module D1 {
+        header "D1.h"
+      }
+    }
+  }
+}
+module A2 {
+  explicit module B2 {
+    header "B2.h"
+  }
+}
+
+//--- Inputs/B1.h
+#pragma once
+
+#include "C1.h"
+#include "D1.h"
+
+// CHECK-B1: import A1.B1.C1
+// CHECK-B1: import A1.B1.C1.D1
+
+typedef int b1_t;
+
+b1_t b1b(void * _Nonnull __sized_by(size), int size);
+c1_t b1c(void * _Nonnull __sized_by(size), int size);
+d1_t b1d(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A1.b1b:
+// DUMP-NEXT: imports for @__swiftmacro_So3b1b15_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+// DUMP-NEXT: imports for A1.b1c:
+// DUMP-NEXT: imports for @__swiftmacro_So3b1c15_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+// DUMP-NEXT: imports for A1.b1d:
+// DUMP-NEXT: imports for @__swiftmacro_So3b1d15_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/C1.h
+#pragma once
+
+#include "D1.h"
+
+// CHECK-C1: import A1.B1.C1.D1
+
+typedef int c1_t;
+
+
+//--- Inputs/D1.h
+#pragma once
+
+#define __sized_by(s) __attribute__((__sized_by__(s)))
+
+typedef int d1_t;
+
+//--- Inputs/B2.h
+#pragma once
+
+#include "B1.h"
+#include "C1.h"
+#include "D1.h"
+
+// CHECK-B2-NOT: import
+
+b1_t b2b(void * _Nonnull __sized_by(size), int size);
+c1_t b2c(void * _Nonnull __sized_by(size), int size);
+d1_t b2d(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A2.b2b:
+// DUMP-NEXT: imports for @__swiftmacro_So3b2b15_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   B2
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+// DUMP-NEXT: imports for A2.b2c:
+// DUMP-NEXT: imports for @__swiftmacro_So3b2c15_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   B2
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+// DUMP-NEXT: imports for A2.b2d:
+// DUMP-NEXT: imports for @__swiftmacro_So3b2d15_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   B2
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+// DUMP-NOT: imports
diff --git a/test/Interop/C/swiftify-import/clang-includes-noexport.swift b/test/Interop/C/swiftify-import/clang-includes-noexport.swift
new file mode 100644
index 0000000000000..109a0840c8c10
--- /dev/null
+++ b/test/Interop/C/swiftify-import/clang-includes-noexport.swift
@@ -0,0 +1,60 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %target-swift-ide-test -print-module -module-to-print=ClangIncludesNoExportModule -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s
+
+// swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesNoExport.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesNoExport.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s -cxx-interoperability-mode=default
+
+import ClangIncludesNoExportModule
+
+// CHECK:      import ModuleA
+// CHECK-NEXT: import ModuleB
+// CHECK-NOT:  import
+// CHECK-EMPTY:
+
+// CHECK-NEXT: func basic_include(_ p: UnsafePointer<a_t>!, _ len: a_t)
+// CHECK-NEXT: func non_exported_include(_ p: UnsafePointer<b_t>!, _ len: b_t)
+// CHECK-NEXT: func submodule_include(_ p: UnsafePointer<c_t>!, _ len: c_t)
+// CHECK-NEXT: func explicit_submodule_include(_ p: UnsafePointer<d_t>!, _ len: d_t)
+// CHECK-NEXT: func deep_submodule_noexport(_ p: UnsafePointer<e_t>!, _ len: e_t)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func basic_include(_ p: Span<a_t>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func deep_submodule_noexport(_ p: Span<e_t>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func explicit_submodule_include(_ p: Span<d_t>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func non_exported_include(_ p: Span<b_t>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func submodule_include(_ p: Span<c_t>)
+
+public func callBasicInclude(_ p: Span<CInt>) {
+  basic_include(p)
+}
+
+public func callNonExported(_ p: Span<CInt>) {
+  non_exported_include(p)
+}
+
+public func callSubmoduleInclude(_ p: Span<CInt>) {
+  submodule_include(p)
+}
+
+public func callExplicitSubmoduleInclude(_ p: Span<CInt>) {
+  explicit_submodule_include(p)
+}
+
+public func callDeepSubmoduleNoexport(_ p: Span<CInt>) {
+  deep_submodule_noexport(p)
+}
diff --git a/test/Interop/C/swiftify-import/clang-includes-redundant-imports.swift b/test/Interop/C/swiftify-import/clang-includes-redundant-imports.swift
new file mode 100644
index 0000000000000..0ea13db6ee4c4
--- /dev/null
+++ b/test/Interop/C/swiftify-import/clang-includes-redundant-imports.swift
@@ -0,0 +1,375 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -dump-source-file-imports -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift 2>&1 | %FileCheck %s --check-prefix DUMP
+// RUN: %target-swift-frontend -dump-source-file-imports -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift -cxx-interoperability-mode=default 2>&1 | %FileCheck %s --check-prefix DUMP --check-prefix DUMP-CXX
+
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-A1 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1.B1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-B1 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1.B1.C1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-C1 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1.B1.C1.D1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-D1 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1.E1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-E1 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1.E1.F1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-F1 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A1.E1.G1 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-G1 --implicit-check-not=import --match-full-lines
+
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A2.B2 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-B2 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A2.B2.C2 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-C2 --implicit-check-not=import --match-full-lines
+// RUN: %target-swift-ide-test -print-module -module-print-hidden -module-to-print=A2.B2.C2.D2 -plugin-path %swift-plugin-dir -I %t/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --check-prefix CHECK-D2 --implicit-check-not=import --match-full-lines
+
+//--- test.swift
+import A1
+import A1.B1
+import A1.B1.C1
+import A1.B1.C1.D1
+import A1.E1
+
+import A2.B2
+import A2.B2.C2
+
+// DUMP: imports for {{.*}}/test.swift:
+// DUMP-NEXT:   Swift
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   E1
+// DUMP-NEXT:   B2
+// DUMP-NEXT:   A2
+// DUMP-NEXT:   C2
+
+public func callUnsafe(_ p: UnsafeMutableRawPointer) {
+  let _ = a1(p, 13)
+  let _ = b1(p, 13)
+  let _ = c1(p, 13)
+  let _ = d1(p, 13)
+  let _ = e1_1(p, 13)
+  let _ = e1_2(p, 13)
+  let _ = b2_1(p, 13)
+  let _ = b2_2(p, 13)
+  let _ = c2(p, 13)
+  let _ = d2(p, 13)
+}
+
+public func callSafe(_ p: UnsafeMutableRawBufferPointer) {
+  let _ = a1(p)
+  let _ = b1(p)
+  let _ = c1(p)
+  let _ = d1(p)
+  let _ = e1_1(p)
+  let _ = e1_2(p)
+  let _ = b2_1(p)
+  let _ = b2_2(p)
+  let _ = c2(p)
+  let _ = d2(p)
+}
+
+//--- Inputs/module.modulemap
+module A1 {
+  header "A1.h"
+  explicit module B1 {
+    header "B1.h"
+    module C1 {
+      header "C1.h"
+      export D1
+      explicit module D1 {
+        header "D1.h"
+      }
+    }
+  }
+  module E1 {
+    header "E1.h"
+
+    // F1 and G1 are not imported directly from Swift - G1 is implicitly
+    // reexported by E1, but F1 ust be implicitly loaded for its decl to be visible
+    explicit module F1 {
+      header "F1.h"
+    }
+    module G1 {
+      header "G1.h"
+    }
+  }
+}
+module A2 {
+  module B2 {
+    header "B2.h"
+
+    explicit module C2 {
+      header "C2.h"
+
+      module D2 {
+        header "D2.h"
+
+        module E2 {
+          header "E2.h"
+        }
+      }
+    }
+  }
+}
+
+//--- Inputs/A1.h
+#pragma once
+
+#include "E1.h"
+#include "B1.h"
+
+// CHECK-A1: import A1.B1
+// CHECK-A1: @_exported import A1.E1
+
+f1_t  a1(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A1.a1:
+// DUMP-NEXT: imports for @__swiftmacro_So2a115_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   F1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/B1.h
+#pragma once
+
+#include "A1.h"
+#include "F1.h"
+#include "C1.h"
+
+// CHECK-B1: import A1
+// CHECK-B1: @_exported import A1.B1.C1
+
+c1_t  b1(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A1.b1:
+// DUMP-NEXT: imports for @__swiftmacro_So2b115_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   F1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/C1.h
+#pragma once
+
+typedef int c1_t;
+#include "D1.h"
+
+// CHECK-C1: @_exported import A1.B1.C1.D1
+
+f1_t  c1(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A1.c1:
+// DUMP-NEXT: imports for @__swiftmacro_So2c115_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   F1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/D1.h
+#pragma once
+
+#include "F1.h"
+
+// CHECK-D1-NOT: import
+
+f1_t d1(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A1.d1:
+// DUMP-NEXT: imports for @__swiftmacro_So2d115_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   F1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/E1.h
+#pragma once
+
+#include "A1.h"
+#include "B1.h"
+#include "C1.h"
+#include "D1.h"
+#include "G1.h"
+
+// CHECK-E1: import A1
+// CHECK-E1: import A1.E1.F1
+// CHECK-E1: @_exported import A1.E1.G1
+
+f1_t e1_1(void * _Nonnull __sized_by(size), int size);
+g1_t e1_2(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A1.e1_1:
+// DUMP-NEXT: imports for @__swiftmacro_So4e1_115_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   F1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+// DUMP-NEXT: imports for A1.e1_2:
+// DUMP-NEXT: imports for @__swiftmacro_So4e1_215_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   B1
+// DUMP-NEXT:   F1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/F1.h
+#pragma once
+
+// CHECK-F1-NOT: import
+
+#define __sized_by(s) __attribute__((__sized_by__(s)))
+
+typedef int f1_t;
+
+//--- Inputs/G1.h
+#pragma once
+
+// CHECK-G1-NOT: import
+
+typedef int g1_t;
+
+//--- Inputs/B2.h
+#pragma once
+
+#include "A1.h"
+#include "B1.h"
+#include "C1.h"
+#include "C2.h"
+#include "D1.h"
+
+// CHECK-B2: import A1
+// CHECK-B2: import A2.B2.C2
+
+
+c1_t b2_1(void * _Nonnull __sized_by(size), int size);
+c2_t b2_2(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A2.b2_1:
+// DUMP-NEXT: imports for @__swiftmacro_So4b2_115_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   C2
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+// DUMP-NEXT: imports for A2.b2_2:
+// DUMP-NEXT: imports for @__swiftmacro_So4b2_215_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   C2
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/C2.h
+#pragma once
+
+#include "D2.h"
+#include "B1.h"
+#include "C1.h"
+
+// CHECK-C2: @_exported import A2.B2.C2.D2
+
+typedef int c2_t;
+
+e2_t c2(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A2.c2:
+// DUMP-NEXT: imports for @__swiftmacro_So2c215_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   C2
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/D2.h
+#pragma once
+
+#include "E2.h"
+
+// CHECK-D2: @_exported import A2.B2.C2.D2.E2
+
+e2_t d2(void * _Nonnull __sized_by(size), int size);
+
+// DUMP-NEXT: imports for A2.d2:
+// DUMP-NEXT: imports for @__swiftmacro_So2d215_SwiftifyImportfMp_.swift:
+// DUMP-NEXT:   Swift
+// DUMP-NEXT:   C2
+// DUMP-NEXT:   D1
+// DUMP-NEXT:   A1
+// DUMP-NEXT:   C1
+// DUMP-NEXT:   B1
+// DUMP-CXX-NEXT:   CxxShim
+// DUMP-CXX-NEXT:   Cxx
+// DUMP-NEXT:   _StringProcessing
+// DUMP-NEXT:   _SwiftConcurrencyShims
+// DUMP-NEXT:   _Concurrency
+// DUMP-NEXT:   SwiftOnoneSupport
+
+//--- Inputs/E2.h
+#pragma once
+
+#define __sized_by(s) __attribute__((__sized_by__(s)))
+
+typedef int e2_t;
+
+// DUMP-NOT: imports
diff --git a/test/Interop/C/swiftify-import/clang-includes.swift b/test/Interop/C/swiftify-import/clang-includes.swift
new file mode 100644
index 0000000000000..aa845b6c47521
--- /dev/null
+++ b/test/Interop/C/swiftify-import/clang-includes.swift
@@ -0,0 +1,60 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %target-swift-ide-test -print-module -module-to-print=ClangIncludesModule -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s
+
+// swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludes.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludes.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s -cxx-interoperability-mode=default
+
+import ClangIncludesModule
+
+// CHECK:      @_exported import ModuleA
+// CHECK-NEXT: @_exported import ModuleB
+// CHECK-NOT:  import
+// CHECK-EMPTY:
+
+// CHECK-NEXT: func basic_include(_ p: UnsafePointer<a_t>!, _ len: a_t)
+// CHECK-NEXT: func non_exported_include(_ p: UnsafePointer<b_t>!, _ len: b_t)
+// CHECK-NEXT: func submodule_include(_ p: UnsafePointer<c_t>!, _ len: c_t)
+// CHECK-NEXT: func explicit_submodule_include(_ p: UnsafePointer<d_t>!, _ len: d_t)
+// CHECK-NEXT: func deep_submodule_noexport(_ p: UnsafePointer<e_t>!, _ len: e_t)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func basic_include(_ p: Span<a_t>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func deep_submodule_noexport(_ p: Span<e_t>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func explicit_submodule_include(_ p: Span<d_t>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func non_exported_include(_ p: Span<b_t>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func submodule_include(_ p: Span<c_t>)
+
+public func callBasicInclude(_ p: Span<CInt>) {
+  basic_include(p)
+}
+
+public func callNonExported(_ p: Span<CInt>) {
+  non_exported_include(p)
+}
+
+public func callSubmoduleInclude(_ p: Span<CInt>) {
+  submodule_include(p)
+}
+
+public func callExplicitSubmoduleInclude(_ p: Span<CInt>) {
+  explicit_submodule_include(p)
+}
+
+public func callDeepSubmoduleNoexport(_ p: Span<CInt>) {
+  deep_submodule_noexport(p)
+}
diff --git a/test/Interop/C/swiftify-import/comments.swift b/test/Interop/C/swiftify-import/comments.swift
new file mode 100644
index 0000000000000..2dcd0e19e203e
--- /dev/null
+++ b/test/Interop/C/swiftify-import/comments.swift
@@ -0,0 +1,52 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %target-swift-ide-test -print-module -module-to-print=CommentsClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s --strict-whitespace --match-full-lines
+
+// Check that doc comments are carried over from clang to the safe macro expansion.
+
+// CHECK:func begin()
+// CHECK-NEXT:func lineComment(_ len: Int32, _ p: UnsafeMutablePointer<Int32>!)
+
+// CHECK-NEXT:/// line doc comment
+// CHECK-NEXT:/// 
+// CHECK-NEXT:/// Here's a more complete description.
+// CHECK-NEXT:///
+// CHECK-NEXT:/// @param len the buffer length
+// CHECK-NEXT:/// @param p the buffer
+// CHECK-NEXT:func lineDocComment(_ len: Int32, _ p: UnsafeMutablePointer<Int32>!)
+
+// CHECK-NEXT:func blockComment(_ len: Int32, _ p: UnsafeMutablePointer<Int32>!)
+
+// CHECK-NEXT:/**
+// CHECK-NEXT: * block doc comment
+// CHECK-NEXT: * 
+// CHECK-NEXT: * NB: it's very important to pass the correct length to this function
+// CHECK-NEXT: * @param len don't mess this one up
+// CHECK-NEXT: * @param p   some integers to play with
+// CHECK-NEXT: */
+// CHECK-NEXT:func blockDocComment(_ len: Int32, _ p: UnsafeMutablePointer<Int32>!)
+
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @_disfavoredOverload public func blockComment(_ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT:/**
+// CHECK-NEXT: * block doc comment
+// CHECK-NEXT: * 
+// CHECK-NEXT: * NB: it's very important to pass the correct length to this function
+// CHECK-NEXT: * @param len don't mess this one up
+// CHECK-NEXT: * @param p   some integers to play with
+// CHECK-NEXT: */
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @_disfavoredOverload public func blockDocComment(_ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @_disfavoredOverload public func lineComment(_ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT:/// line doc comment
+// CHECK-NEXT:/// 
+// CHECK-NEXT:/// Here's a more complete description.
+// CHECK-NEXT:///
+// CHECK-NEXT:/// @param len the buffer length
+// CHECK-NEXT:/// @param p the buffer
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @_disfavoredOverload public func lineDocComment(_ p: UnsafeMutableBufferPointer<Int32>)
diff --git a/test/Interop/C/swiftify-import/counted-by-lifetimebound.swift b/test/Interop/C/swiftify-import/counted-by-lifetimebound.swift
new file mode 100644
index 0000000000000..d37dea6e0e258
--- /dev/null
+++ b/test/Interop/C/swiftify-import/counted-by-lifetimebound.swift
@@ -0,0 +1,108 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+// REQUIRES: swift_feature_Lifetimes
+
+// RUN: %target-swift-ide-test -print-module -module-to-print=CountedByLifetimeboundClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers -Xcc -Wno-nullability-completeness | %FileCheck %s
+
+// swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/CountedByLifetimebound.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers -enable-experimental-feature Lifetimes -strict-memory-safety -warnings-as-errors -Xcc -Werror -Xcc -Wno-nullability-completeness %s
+
+// Check that ClangImporter correctly infers and expands @_SwiftifyImport macros for functions with __sized_by __lifetimebound parameters and return values.
+
+import CountedByLifetimeboundClang
+
+// CHECK:      /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func complexExpr(_ len: Int32, _ offset: Int32, _ p: inout MutableSpan<Int32>) -> MutableSpan<Int32>
+
+// CHECK:      /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func constant(_ p: inout MutableSpan<Int32>?) -> MutableSpan<Int32>?
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(borrow p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func noncountedLifetime(_ len: Int32, _ p: UnsafeMutablePointer<Int32>!) -> MutableSpan<Int32>
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nonnull(_ len: Int32, _ p: inout MutableSpan<Int32>) -> MutableSpan<Int32>
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullUnspecified(_ len: Int32, _ p: inout MutableSpan<Int32>) -> MutableSpan<Int32>
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullable(_ len: Int32, _ p: inout MutableSpan<Int32>?) -> MutableSpan<Int32>?
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func shared(_ p: inout MutableSpan<Int32>) -> MutableSpan<Int32>
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func simple(_ len: Int32, _ p: inout MutableSpan<Int32>) -> MutableSpan<Int32>
+
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callComplexExpr(_ p: inout MutableSpan<CInt>) {
+  let _: MutableSpan<CInt> = complexExpr(73, 37, &p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNonnull(_ p: inout MutableSpan<CInt>) {
+  let _: MutableSpan<CInt> = nonnull(73, &p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNullUnspecified(_ p: inout MutableSpan<CInt>) {
+  let _: MutableSpan<CInt> = nullUnspecified(73, &p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNullable(_ p: inout MutableSpan<CInt>?) {
+  let _: MutableSpan<CInt> = nullable(73, &p)!
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callShared(_ p: inout MutableSpan<CInt>) {
+  let _: MutableSpan<CInt> = shared(&p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callSimple(_ p: inout MutableSpan<CInt>) {
+  let _: MutableSpan<CInt> = simple(73, &p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNoncountedLifetime(_ p: UnsafeMutablePointer<CInt>) {
+  let _: MutableSpan<CInt> = unsafe noncountedLifetime(73, p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callConstant(_ p: inout MutableSpan<CInt>?) {
+  let _: MutableSpan<CInt>? = constant(&p)
+}
diff --git a/test/Interop/C/swiftify-import/counted-by-no-swiftify.swift b/test/Interop/C/swiftify-import/counted-by-no-swiftify.swift
new file mode 100644
index 0000000000000..ff565150f4126
--- /dev/null
+++ b/test/Interop/C/swiftify-import/counted-by-no-swiftify.swift
@@ -0,0 +1,18 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=CountedByClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers -Xcc -Werror -Xcc -Wno-nullability-completeness -Xcc -Wno-div-by-zero -Xcc -Wno-pointer-to-int-cast  | %FileCheck %s
+
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// These functions use __counted_by annotations that are not syntactically valid
+// in Swift, so they should not be Swiftified
+
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} derefLen
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} lNot
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} lAnd
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} lOr
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} floatCastToInt
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} pointerCastToInt
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} nanAsInt
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} unsignedLiteral
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} longLiteral
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} sizeofType
+// CHECK-NOT: @_alwaysEmitIntoClient {{.*}} sizeofParam
diff --git a/test/Interop/C/swiftify-import/counted-by-noescape.swift b/test/Interop/C/swiftify-import/counted-by-noescape.swift
index 339789074c959..fb778a3cd92a7 100644
--- a/test/Interop/C/swiftify-import/counted-by-noescape.swift
+++ b/test/Interop/C/swiftify-import/counted-by-noescape.swift
@@ -1,37 +1,244 @@
 // REQUIRES: swift_feature_SafeInteropWrappers
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
-// RUN: %target-swift-ide-test -print-module -module-to-print=CountedByNoEscapeClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers -enable-experimental-feature LifetimeDependence | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -module-to-print=CountedByNoEscapeClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers -enable-experimental-feature Lifetimes -Xcc -Werror -Xcc -Wno-ignored-attributes -Xcc -Wno-nullability-completeness | %FileCheck %s
 
 // swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/CountedByNoEscape.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/CountedByNoEscape.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers -enable-experimental-feature Lifetimes -strict-memory-safety -warnings-as-errors -Xcc -Werror -Xcc -Wno-ignored-attributes -Xcc -Wno-nullability-completeness %s
 
 // Check that ClangImporter correctly infers and expands @_SwiftifyImport macros for functions with __counted_by __noescape parameters.
 
 import CountedByNoEscapeClang
 
-// CHECK:      @lifetime(p: copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func complexExpr(_ len: Int32, _ offset: Int32, _ p: inout MutableSpan<Int32>)
-// CHECK-NEXT: @lifetime(p: copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nonnull(_ p: inout MutableSpan<Int32>)
-// CHECK-NEXT: @lifetime(p: copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nullUnspecified(_ p: inout MutableSpan<Int32>)
-// CHECK-NEXT: @lifetime(copy p)
-// CHECK-NEXT: @lifetime(p: copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func returnLifetimeBound(_ len1: Int32, _ p: inout MutableSpan<Int32>) -> MutableSpan<Int32>
+// CHECK:      /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(_anonymous_param1: copy _anonymous_param1)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func anonymous(_ _anonymous_param1: inout MutableSpan<Int32>?)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(`func`: copy `func`)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func clash(func: inout MutableSpan<Int32>?, clash where: Int32)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(_clash2_param1: copy _clash2_param1)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func clash2(func _clash2_param1: inout MutableSpan<Int32>?, clash2 _clash2_param2: Int32)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func complexExpr(_ len: Int32, _ offset: Int32, _ p: inout MutableSpan<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(_func_param1: copy _func_param1)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func `func`(_ _func_param1: inout MutableSpan<Int32>?)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(`func`: copy `func`)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func funcRenamed(func: inout MutableSpan<Int32>?, extension: Int32, init: Int32, open: Int32, var: Int32, is: Int32, as: Int32, in: Int32, guard: Int32, where: Int32) -> UnsafeMutableRawPointer!
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(_funcRenamedAnon_param1: copy _funcRenamedAnon_param1)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func funcRenamedAnon(func _funcRenamedAnon_param1: inout MutableSpan<Int32>?, extension _funcRenamedAnon_param2: Int32, init _funcRenamedAnon_param3: Int32, open _funcRenamedAnon_param4: Int32, var _funcRenamedAnon_param5: Int32, is _funcRenamedAnon_param6: Int32, as _funcRenamedAnon_param7: Int32, in _funcRenamedAnon_param8: Int32, guard _funcRenamedAnon_param9: Int32, where _funcRenamedAnon_param10: Int32) -> UnsafeMutableRawPointer!
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(_in_param1: copy _in_param1)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func `in`(func _in_param1: inout MutableSpan<Int32>?, in _in_param2: Int32)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(`func`: copy `func`)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func keyword(_ func: inout MutableSpan<Int32>?, _ extension: Int32, _ init: Int32, _ open: Int32, _ var: Int32, _ is: Int32, _ as: Int32, _ in: Int32, _ guard: Int32, _ where: Int32)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func keywordType(_ p: inout MutableSpan<actor?>, _ p2: actor) -> actor
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(_lenName_param2: copy _lenName_param2)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func lenName(_ _lenName_param0: Int32, _ _lenName_param1: Int32, _ _lenName_param2: inout MutableSpan<Int32>?)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nonnull(_ p: inout MutableSpan<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullUnspecified(_ p: inout MutableSpan<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullable(_ p: inout MutableSpan<Int32>?)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(`func`: copy `func`)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func open(func: inout MutableSpan<Int32>?, open where: Int32)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(_pointerName_param1: copy _pointerName_param1)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func pointerName(_ _pointerName_param1: inout MutableSpan<Int32>?)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func returnLifetimeBound(_ len1: Int32, _ p: inout MutableSpan<Int32>) -> MutableSpan<Int32>
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
 // CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func returnPointer(_ len: Int32) -> UnsafeMutableBufferPointer<Int32>
-// CHECK-NEXT: @lifetime(p1: copy p1)
-// CHECK-NEXT: @lifetime(p2: copy p2)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func shared(_ len: Int32, _ p1: inout MutableSpan<Int32>, _ p2: inout MutableSpan<Int32>)
-// CHECK-NEXT: @lifetime(p: copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func simple(_ p: inout MutableSpan<Int32>)
-// CHECK-NEXT: @lifetime(p: copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func swiftAttr(_ p: inout MutableSpan<Int32>)
 
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(p1: copy p1)
+// CHECK-NEXT: @_lifetime(p2: copy p2)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func shared(_ p1: inout MutableSpan<Int32>, _ p2: inout MutableSpan<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func simple(_ p: inout MutableSpan<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func swiftAttr(_ p: inout MutableSpan<Int32>)
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callComplexExpr(_ p: inout MutableSpan<CInt>) {
+  complexExpr(CInt(p.count), 1, &p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callNonnull(_ p: inout MutableSpan<CInt>) {
+  nonnull(&p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callNullUnspecified(_ p: inout MutableSpan<CInt>) {
+  nullUnspecified(&p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callNullable(_ p: inout MutableSpan<CInt>?) {
+  nullable(&p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callReturnLifetimeBound(_ p: inout MutableSpan<CInt>) {
+  let _: MutableSpan<CInt> = returnLifetimeBound(2, &p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
 @inlinable
 public func callReturnPointer() {
-  let a: UnsafeMutableBufferPointer<CInt>? = returnPointer(4) // call wrapper
-  let b: UnsafeMutablePointer<CInt>? = returnPointer(4) // call unsafe interop
+  let _: UnsafeMutableBufferPointer<CInt>? = unsafe returnPointer(4) // call wrapper
+  let _: UnsafeMutablePointer<CInt>? = unsafe returnPointer(4) // call unsafe interop
 }
 
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@_lifetime(p2: copy p2)
+@inlinable
+public func callShared(_ p: inout MutableSpan<CInt>, _ p2: inout MutableSpan<CInt>) {
+  shared(&p, &p2)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callSimple(_ p: inout MutableSpan<CInt>) {
+  simple(&p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callSwiftAttr(_ p: inout MutableSpan<CInt>) {
+  swiftAttr(&p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callAnonymous(_ p: inout MutableSpan<CInt>?) {
+  anonymous(&p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callKeyword(_ p: inout MutableSpan<CInt>?) {
+  keyword(&p, 1, 2, 3, 4, 5, 6, 7, 8, 9)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callFunc(_ p: inout MutableSpan<CInt>?) {
+  `func`(&p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callFuncRenameKeyword(_ p: inout MutableSpan<CInt>?) {
+  let _ = unsafe funcRenamed(func: &p, extension: 1, init: 2, open: 3, var: 4, is: 5, as: 6, in: 7, guard: 8, where: 9)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callFuncRenameClash(_ p: inout MutableSpan<CInt>?) {
+  clash(func: &p, clash: 1)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callFuncRenameClashKeyword(_ p: inout MutableSpan<CInt>?) {
+  `open`(func: &p, open: 1)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callFuncRenameClashKeywordAnon(_ p: inout MutableSpan<CInt>?) {
+  `in`(func: &p, in: 1)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callPointerName(_ p: inout MutableSpan<CInt>?) {
+  pointerName(&p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@_lifetime(p: copy p)
+@inlinable
+public func callLenName(_ p: inout MutableSpan<CInt>?) {
+  lenName(CInt(p?.count ?? 0), 2, &p)
+}
diff --git a/test/Interop/C/swiftify-import/counted-by.swift b/test/Interop/C/swiftify-import/counted-by.swift
index ebe038cddb200..790c60fb1e022 100644
--- a/test/Interop/C/swiftify-import/counted-by.swift
+++ b/test/Interop/C/swiftify-import/counted-by.swift
@@ -1,26 +1,167 @@
 // REQUIRES: swift_feature_SafeInteropWrappers
 
-// RUN: %target-swift-ide-test -print-module -module-to-print=CountedByClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -module-to-print=CountedByClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers -Xcc -Werror -Xcc -Wno-nullability-completeness -Xcc -Wno-div-by-zero -Xcc -Wno-pointer-to-int-cast | %FileCheck %s
 
 // swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/CountedBy.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/CountedBy.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers -strict-memory-safety -warnings-as-errors -Xcc -Werror -Xcc -Wno-nullability-completeness -Xcc -Wno-div-by-zero -Xcc -Wno-pointer-to-int-cast %s
 
 // Check that ClangImporter correctly infers and expands @_SwiftifyImport macros for functions with __counted_by parameters.
 
 import CountedByClang
 
-// CHECK:      @_alwaysEmitIntoClient public func complexExpr(_ len: Int{{.*}}, _ offset: Int{{.*}}, _ p: UnsafeMutableBufferPointer<Int{{.*}}>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nonnull(_  p: UnsafeMutableBufferPointer<Int{{.*}}>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nullUnspecified(_  p: UnsafeMutableBufferPointer<Int{{.*}}>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nullable(_  p: UnsafeMutableBufferPointer<Int{{.*}}>?)
+
+// CHECK:      /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func binaryLiteral(_ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func bitshift(_ m: Int32, _ n: Int32, _ o: Int32, _ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func bitwise(_ m: Int32, _ n: Int32, _ o: Int32, _ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func complexExpr(_ len: Int{{.*}}, _ offset: Int{{.*}}, _ p: UnsafeMutableBufferPointer<Int{{.*}}>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func constFloatCastedToInt(_ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func constInt(_ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func hexLiteral(_ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nonnull(_  p: UnsafeMutableBufferPointer<Int{{.*}}>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullUnspecified(_  p: UnsafeMutableBufferPointer<Int{{.*}}>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullable(_  p: UnsafeMutableBufferPointer<Int{{.*}}>?)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func octalLiteral(_ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func offByOne(_ len: Int32, _ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func offBySome(_ len: Int32, _ offset: Int32, _ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
 // CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func returnPointer(_  len: Int{{.*}}) -> UnsafeMutableBufferPointer<Int{{.*}}>
-// CHECK-NEXT: @_alwaysEmitIntoClient public func shared(_ len: Int{{.*}}, _ p1: UnsafeMutableBufferPointer<Int{{.*}}>, _ p2: UnsafeMutableBufferPointer<Int{{.*}}>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func simple(_  p: UnsafeMutableBufferPointer<Int{{.*}}>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func swiftAttr(_  p: UnsafeMutableBufferPointer<Int{{.*}}>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func scalar(_ m: Int32, _ n: Int32, _ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func shared(_ p1: UnsafeMutableBufferPointer<Int{{.*}}>, _ p2: UnsafeMutableBufferPointer<Int{{.*}}>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func simple(_  p: UnsafeMutableBufferPointer<Int{{.*}}>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func simpleFlipped(_  p: UnsafeMutableBufferPointer<Int{{.*}}>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func swiftAttr(_  p: UnsafeMutableBufferPointer<Int{{.*}}>)
+
+@inlinable
+public func callBitshift(_ m: CInt, n: CInt, o: CInt, _ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe bitshift(m, n, o, p)
+}
+
+@inlinable
+public func callBitwise(_ m: CInt, n: CInt, o: CInt, _ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe bitwise(m, n, o, p)
+}
+
+@inlinable
+public func callComplexExpr(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe complexExpr(CInt(p.count), 1, p)
+}
+
+@inlinable
+public func callConstFloatCastedToInt(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe constFloatCastedToInt(p)
+}
+
+@inlinable
+public func callConstInt(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe constInt(p)
+}
+
+@inlinable
+public func callNonnull(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe nonnull(p)
+}
+
+@inlinable
+public func callNullUnspecified(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe nullUnspecified(p)
+}
+
+@inlinable
+public func callNullable(_ p: UnsafeMutableBufferPointer<CInt>?) {
+  unsafe nullable(p)
+}
+
+@inlinable
+public func callOctalLiteral(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe octalLiteral(p)
+}
+
+@inlinable
+public func callOffByOne(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe offByOne(0, p)
+}
+
+@inlinable
+public func callOffBySome(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe offBySome(0, 1, p)
+}
 
 @inlinable
 public func callReturnPointer() {
-  let a: UnsafeMutableBufferPointer<CInt>? = returnPointer(4) // call wrapper
-  let b: UnsafeMutablePointer<CInt>? = returnPointer(4) // call unsafe interop
+  let _: UnsafeMutableBufferPointer<CInt>? = unsafe returnPointer(4) // call wrapper
+  let _: UnsafeMutablePointer<CInt>? = unsafe returnPointer(4) // call unsafe interop
+}
+
+@inlinable
+public func callScalar(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe scalar(4, 2, p)
+}
+
+@inlinable
+public func callShared(_ p: UnsafeMutableBufferPointer<CInt>, _ p2: UnsafeMutableBufferPointer<CInt>) {
+  unsafe shared(p, p2)
+}
+
+@inlinable
+public func callSimple(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe simple(p)
+}
+
+@inlinable
+public func callSimpleIndirectOriginal(_ p: UnsafeMutablePointer<CInt>) {
+  let f = unsafe simple
+  unsafe f(13, p)
+}
+
+@inlinable
+public func callSimpleIndirectOverload(_ p: UnsafeMutableBufferPointer<CInt>) {
+  let f: (UnsafeMutableBufferPointer<CInt>) -> Void = unsafe simple
+  unsafe f(p)
+}
+
+@inlinable
+public func callSimpleFlipped(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe simpleFlipped(p)
+}
+
+@inlinable
+public func callSwiftAttr(_ p: UnsafeMutableBufferPointer<CInt>) {
+  unsafe swiftAttr(p)
 }
diff --git a/test/Interop/C/swiftify-import/import-as-instance-method.swift b/test/Interop/C/swiftify-import/import-as-instance-method.swift
new file mode 100644
index 0000000000000..2360574e7fb3f
--- /dev/null
+++ b/test/Interop/C/swiftify-import/import-as-instance-method.swift
@@ -0,0 +1,212 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/Test.swiftmodule -I %t%{fs-sep}Inputs -enable-experimental-feature SafeInteropWrappers -strict-memory-safety -verify -verify-additional-file %t%{fs-sep}Inputs%{fs-sep}instance.h %t/test.swift -I %bridging-path -DVERIFY
+// RUN: env SWIFT_BACKTRACE="" %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/Test.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers -strict-memory-safety -warnings-as-errors -Xcc -Werror %t/test.swift -dump-macro-expansions -I %bridging-path 2> %t/out.txt
+// RUN: diff --strip-trailing-cr %t/out.txt %t/out.expected
+
+//--- test.swift
+import Instance
+
+@available(SwiftStdlib 5.8, *)
+func foo(_ p: inout MutableSpan<CInt>, a: A, aa: inout A, c: C, b: B, bb: inout B) {
+  aa.basic(&p)
+  aa.bar(&p)
+  a.constSelf(&p)
+  a.valSelf(&p)
+  let _: MutableSpan<CInt> = a.lifetimeBoundSelf(3)
+  c.refSelf(&p)
+  b.nonescaping(&p)
+  let _: MutableSpan<CInt> = bb.nonescapingLifetimebound(73)
+
+#if VERIFY
+  aa.countedSelf(&p)
+  a.basic(&p) // expected-error{{cannot use mutating member on immutable value: 'a' is a 'let' constant}}
+#endif
+}
+
+//--- Inputs/instance.h
+#include <ptrcheck.h>
+#include <lifetimebound.h>
+#include <swift/bridging>
+
+struct A {};
+struct SWIFT_NONESCAPABLE B {};
+struct SWIFT_IMMORTAL_REFERENCE C {};
+
+void basic(struct A *a, int * __counted_by(len) p __noescape, int len) __attribute__((swift_name("A.basic(self:_:_:)")));
+
+void renamed(struct A *a, int * __counted_by(len) p __noescape, int len) __attribute__((swift_name("A.bar(self:_:_:)")));
+
+void countedSelf(struct A * __counted_by(len)
+  a, // expected-warning{{bounds attribute '__counted_by' ignored on parameter mapped to 'self'}}
+  int * __counted_by(len) p __noescape, int len)
+  __attribute__((
+  swift_name // expected-note{{swift_name maps free function to instance method here}}
+  ("A.countedSelf(self:_:_:)")));
+
+void constSelf(const struct A *a, int * __counted_by(len) p __noescape, int len) __attribute__((swift_name("A.constSelf(self:_:_:)")));
+
+void valSelf(struct A a, int * __counted_by(len) p __noescape, int len) __attribute__((swift_name("A.valSelf(self:_:_:)")));
+
+void refSelf(struct C *c, int * __counted_by(len) p __noescape, int len) __attribute__((swift_name("C.refSelf(self:_:_:)")));
+
+int * __counted_by(len) lifetimeBoundSelf(struct A a __lifetimebound, int len) __attribute__((swift_name("A.lifetimeBoundSelf(self:_:)")));
+
+void nonescaping(const struct B *d, int * __counted_by(len) p __noescape, int len) __attribute__((swift_name("B.nonescaping(self:_:_:)")));
+
+int * __counted_by(len) nonescapingLifetimebound(struct B *d __lifetimebound, int len) __attribute__((swift_name("B.nonescapingLifetimebound(self:_:)")));
+
+//--- Inputs/module.modulemap
+module Instance {
+  header "instance.h"
+}
+
+//--- out.expected
+@__swiftmacro_So1AV5basic15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public mutating func basic(_ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe basic(_pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So5basic15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@available(swift, obsoleted: 3, renamed: "A.basic(self:_:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public func basic(_ a: UnsafeMutablePointer<A>!, _ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe basic(a, _pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So1AV3bar15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public mutating func bar(_ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe bar(_pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So7renamed15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@available(swift, obsoleted: 3, renamed: "A.bar(self:_:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public func renamed(_ a: UnsafeMutablePointer<A>!, _ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe renamed(a, _pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So1AV9constSelf15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public func constSelf(_ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe constSelf(_pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So9constSelf15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@available(swift, obsoleted: 3, renamed: "A.constSelf(self:_:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public func constSelf(_ a: UnsafePointer<A>!, _ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe constSelf(a, _pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So1AV7valSelf15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public func valSelf(_ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe valSelf(_pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So7valSelf15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@available(swift, obsoleted: 3, renamed: "A.valSelf(self:_:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public func valSelf(_ a: A, _ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe valSelf(a, _pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So1AV17lifetimeBoundSelf15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(borrow self) @_disfavoredOverload
+public func lifetimeBoundSelf(_ len: Int32) -> MutableSpan<Int32> {
+    return unsafe _swiftifyOverrideLifetime(MutableSpan<Int32>(_unsafeStart: unsafe lifetimeBoundSelf(len), count: Int(len)), copying: ())
+}
+------------------------------
+@__swiftmacro_So17lifetimeBoundSelf15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@available(swift, obsoleted: 3, renamed: "A.lifetimeBoundSelf(self:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(borrow a) @_disfavoredOverload
+public func lifetimeBoundSelf(_ a: A, _ len: Int32) -> MutableSpan<Int32> {
+    return unsafe _swiftifyOverrideLifetime(MutableSpan<Int32>(_unsafeStart: unsafe lifetimeBoundSelf(a, len), count: Int(len)), copying: ())
+}
+------------------------------
+@__swiftmacro_So1CV7refSelf15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public func refSelf(_ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe refSelf(_pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So7refSelf15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@available(swift, obsoleted: 3, renamed: "C.refSelf(self:_:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public func refSelf(_ c: C!, _ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe refSelf(c, _pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So1BV11nonescaping15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+public func nonescaping(_ p: inout MutableSpan<Int32>) {
+    let len = Int32(exactly: p.count)!
+    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+      return unsafe nonescaping(_pPtr.baseAddress!, len)
+    }
+}
+------------------------------
+@__swiftmacro_So1BV24nonescapingLifetimebound15_SwiftifyImportfMp_.swift
+------------------------------
+/// This is an auto-generated wrapper for safer interop
+@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(copy self) @_disfavoredOverload
+public mutating func nonescapingLifetimebound(_ len: Int32) -> MutableSpan<Int32> {
+    return unsafe _swiftifyOverrideLifetime(MutableSpan<Int32>(_unsafeStart: unsafe nonescapingLifetimebound(len), count: Int(len)), copying: ())
+}
+------------------------------
diff --git a/test/Interop/C/swiftify-import/sized-by-lifetimebound.swift b/test/Interop/C/swiftify-import/sized-by-lifetimebound.swift
new file mode 100644
index 0000000000000..83ae29fd82920
--- /dev/null
+++ b/test/Interop/C/swiftify-import/sized-by-lifetimebound.swift
@@ -0,0 +1,119 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+// REQUIRES: swift_feature_Lifetimes
+
+// RUN: %target-swift-ide-test -print-module -module-to-print=SizedByLifetimeboundClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers -Xcc -Werror -Xcc -Wno-nullability-completeness | %FileCheck %s
+
+// swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/SizedByLifetimebound.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers -enable-experimental-feature Lifetimes -strict-memory-safety -warnings-as-errors -Xcc -Werror -strict-memory-safety -warnings-as-errors -Xcc -Werror -Xcc -Wno-nullability-completeness %s
+
+// Check that ClangImporter correctly infers and expands @_SwiftifyImport macros for functions with __sized_by __lifetimebound parameters and return values.
+
+import SizedByLifetimeboundClang
+
+// CHECK:      /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func bytesized(_ p: RawSpan) -> MutableRawSpan
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func charsized(_ p: inout MutableRawSpan) -> MutableRawSpan
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func complexExpr(_ len: Int32, _ offset: Int32, _ p: RawSpan) -> RawSpan
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nonnull(_ len: Int32, _ p: RawSpan) -> RawSpan
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(borrow p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nonsizedLifetime(_ len: Int32, _ p: UnsafeRawPointer!) -> RawSpan
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullUnspecified(_ len: Int32, _ p: RawSpan) -> RawSpan
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullable(_ len: Int32, _ p: RawSpan?) -> RawSpan?
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func opaque(_ len: Int32, _ p: RawSpan) -> RawSpan
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func shared(_ p: RawSpan) -> RawSpan
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func simple(_ len: Int32, _ p: RawSpan) -> RawSpan
+
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callComplexExpr(_ p: RawSpan) {
+  let _: RawSpan = complexExpr(73, 37, p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNonnull(_ p: RawSpan) {
+  let _: RawSpan = nonnull(73, p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNullUnspecified(_ p: RawSpan) {
+  let _: RawSpan = nullUnspecified(73, p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNullable(_ p: RawSpan?) {
+  let _: RawSpan = nullable(73, p)!
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callShared(_ p: RawSpan) {
+  let _: RawSpan = shared(p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callSimple(_ p: RawSpan) {
+  let _: RawSpan = simple(73, p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNonsizedLifetime(_ p: UnsafeRawPointer) {
+  let _: RawSpan = unsafe nonsizedLifetime(73, p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callBytesized(_ p: RawSpan) {
+  let _: MutableRawSpan = bytesized(p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+@_lifetime(p: copy p)
+public func callCharsized(_ p: inout MutableRawSpan) {
+  let _: MutableRawSpan = charsized(&p)
+}
diff --git a/test/Interop/C/swiftify-import/sized-by-noescape.swift b/test/Interop/C/swiftify-import/sized-by-noescape.swift
index 2510053201eaa..b3547b81ee87c 100644
--- a/test/Interop/C/swiftify-import/sized-by-noescape.swift
+++ b/test/Interop/C/swiftify-import/sized-by-noescape.swift
@@ -1,19 +1,118 @@
 // REQUIRES: swift_feature_SafeInteropWrappers
+// REQUIRES: swift_feature_Lifetimes
 
-// RUN: %target-swift-ide-test -print-module -module-to-print=SizedByNoEscapeClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -module-to-print=SizedByNoEscapeClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature Lifetimes -enable-experimental-feature SafeInteropWrappers -Xcc -Werror -Xcc -Wno-ignored-attributes -Xcc -Wno-nullability-completeness | %FileCheck %s
 
 // swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/SizedByNoEscape.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/SizedByNoEscape.swiftmodule -I %S/Inputs -enable-experimental-feature Lifetimes -enable-experimental-feature SafeInteropWrappers -strict-memory-safety -warnings-as-errors -Xcc -Werror -Xcc -Wno-ignored-attributes -Xcc -Wno-nullability-completeness %s
 
 // Check that ClangImporter correctly infers and expands @_SwiftifyImport macros for functions with __sized_by __noescape parameters.
 import SizedByNoEscapeClang
 
-// CHECK:      @_alwaysEmitIntoClient public func complexExpr(_ len: Int{{.*}}, _ offset: Int{{.*}}, _ p: RawSpan)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nonnull(_ p: RawSpan)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nullUnspecified(_  p: RawSpan)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func opaque(_  p: RawSpan)
+
+// CHECK:      /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func bytesized(_ _bytesized_param1: RawSpan)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(_charsized_param0: copy _charsized_param0)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func charsized(_  _charsized_param0: inout MutableRawSpan)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func complexExpr(_ len: Int{{.*}}, _ offset: Int{{.*}}, _ p: RawSpan)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nonnull(_ p: RawSpan)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullUnspecified(_  p: RawSpan)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullable(_  p: RawSpan?)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func opaque(_  p: RawSpan)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
 // CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func returnPointer(_ len: Int{{.*}}) -> UnsafeRawBufferPointer
-// CHECK-NEXT: @_alwaysEmitIntoClient public func shared(_ len: Int{{.*}}, _ p1: RawSpan, _ p2: RawSpan)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func simple(_  p: RawSpan)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func swiftAttr(_  p: RawSpan)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func shared(_ p1: RawSpan, _ p2: RawSpan)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func simple(_  p: RawSpan)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func swiftAttr(_  p: RawSpan)
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callComplexExpr(_ p: RawSpan) {
+  complexExpr(CInt(p.byteCount), 1, p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNonnull(_ p: RawSpan) {
+  nonnull(p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNullUnspecified(_ p: RawSpan) {
+  nullUnspecified(p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callNullable(_ p: RawSpan?) {
+  nullable(p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callReturnPointer() {
+  let _: UnsafeRawBufferPointer? = unsafe returnPointer(4) // call wrapper
+  let _: UnsafeRawPointer? = unsafe returnPointer(4) // call unsafe interop
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callShared(_ p: RawSpan, _ p2: RawSpan) {
+  shared(p, p2)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callSimple(_ p: RawSpan) {
+  simple(p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callSwiftAttr(_ p: RawSpan) {
+  swiftAttr(p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+public func callBytesized(_ p: RawSpan) {
+  bytesized(p)
+}
+
+@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@inlinable
+@_lifetime(p: copy p)
+public func callCharsized(_ p: inout MutableRawSpan) {
+  charsized(&p)
+}
diff --git a/test/Interop/C/swiftify-import/sized-by.swift b/test/Interop/C/swiftify-import/sized-by.swift
index 5c6f41abfb172..32aa7e85cd4ca 100644
--- a/test/Interop/C/swiftify-import/sized-by.swift
+++ b/test/Interop/C/swiftify-import/sized-by.swift
@@ -1,21 +1,115 @@
 // REQUIRES: swift_feature_SafeInteropWrappers
 
-// RUN: %target-swift-ide-test -print-module -module-to-print=SizedByClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -module-to-print=SizedByClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers -Xcc -Werror -Xcc -Wno-nullability-completeness | %FileCheck %s
 
 // swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
-// RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/SizedBy.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs -enable-experimental-feature SafeInteropWrappers -strict-memory-safety -warnings-as-errors -Xcc -Werror -Xcc -Wno-nullability-completeness %s
 
 // Check that ClangImporter correctly infers and expands @_SwiftifyImport macros for functions with __sized_by parameters.
 import SizedByClang
 
-// CHECK:      @_alwaysEmitIntoClient public func complexExpr(_ len: Int{{.*}}, _ offset: Int{{.*}}, _ p: UnsafeMutableRawBufferPointer)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nonnull(_  p: UnsafeMutableRawBufferPointer)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nullUnspecified(_  p: UnsafeMutableRawBufferPointer)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func nullable(_  p: UnsafeMutableRawBufferPointer?)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func opaque(_  p: UnsafeRawBufferPointer)
+
+// CHECK:      /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func aliasedBytesized(_  p: UnsafeMutableRawBufferPointer)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func bytesized(_  size: Int{{.*}}) -> UnsafeMutableRawBufferPointer
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func charsized(_  _charsized_param0: UnsafeMutableRawBufferPointer)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func complexExpr(_ len: Int{{.*}}, _ offset: Int{{.*}}, _ p: UnsafeMutableRawBufferPointer)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nonnull(_  p: UnsafeMutableRawBufferPointer)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullUnspecified(_  p: UnsafeMutableRawBufferPointer)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func nullable(_  p: UnsafeMutableRawBufferPointer?)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func opaque(_  p: UnsafeRawBufferPointer)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func opaqueptr(_  p: UnsafeRawBufferPointer)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
 // CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func returnPointer(_ len: Int{{.*}}) -> UnsafeMutableRawBufferPointer
-// CHECK-NEXT: @_alwaysEmitIntoClient public func shared(_ len: Int{{.*}}, _ p1: UnsafeMutableRawBufferPointer, _ p2: UnsafeMutableRawBufferPointer)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func simple(_  p: UnsafeMutableRawBufferPointer)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func swiftAttr(_  p: UnsafeMutableRawBufferPointer)
 
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func shared(_ p1: UnsafeMutableRawBufferPointer, _ p2: UnsafeMutableRawBufferPointer)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func simple(_  p: UnsafeMutableRawBufferPointer)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func swiftAttr(_  p: UnsafeMutableRawBufferPointer)
+
+@inlinable
+public func callComplexExpr(_ p: UnsafeMutableRawBufferPointer) {
+  unsafe complexExpr(CInt(p.count), 1, p)
+}
+
+@inlinable
+public func callNonnull(_ p: UnsafeMutableRawBufferPointer) {
+  unsafe nonnull(p)
+}
+
+@inlinable
+public func callNullUnspecified(_ p: UnsafeMutableRawBufferPointer) {
+  unsafe nullUnspecified(p)
+}
+
+@inlinable
+public func callNullable(_ p: UnsafeMutableRawBufferPointer?) {
+  unsafe nullable(p)
+}
+
+@inlinable
+public func callOpaque(_ p: UnsafeRawBufferPointer) {
+  unsafe opaque(p)
+}
+
+@inlinable
+public func callOpaqueptr(_ p: UnsafeRawBufferPointer) {
+  unsafe opaqueptr(p)
+}
+
+@inlinable
+public func callReturnPointer() {
+  let _: UnsafeMutableRawBufferPointer? = unsafe returnPointer(4) // call wrapper
+  let _: UnsafeMutableRawPointer? = unsafe returnPointer(4) // call unsafe interop
+}
+
+@inlinable
+public func callShared(_ p: UnsafeMutableRawBufferPointer, _ p2: UnsafeMutableRawBufferPointer) {
+  unsafe shared(p, p2)
+}
+
+@inlinable
+public func callSimple(_ p: UnsafeMutableRawBufferPointer) {
+  unsafe simple(p)
+}
+
+@inlinable
+public func callSwiftAttr(_ p: UnsafeMutableRawBufferPointer) {
+  unsafe swiftAttr(p)
+}
+
+@inlinable
+public func callCharsized(_ p: UnsafeMutableRawBufferPointer) {
+  unsafe charsized(p)
+}
+
+@inlinable
+public func callBytesized() {
+  let _: UnsafeMutableRawBufferPointer = unsafe bytesized(37)
+}
+
+@inlinable
+public func callAliasedBytesized(_ p: UnsafeMutableRawBufferPointer) {
+  unsafe aliasedBytesized(p)
+}
diff --git a/test/Interop/Cxx/class/Inputs/closure.h b/test/Interop/Cxx/class/Inputs/closure.h
index 7081ff54c7b08..b842401536f5a 100644
--- a/test/Interop/Cxx/class/Inputs/closure.h
+++ b/test/Interop/Cxx/class/Inputs/closure.h
@@ -10,6 +10,10 @@ struct NonTrivial {
   int *p;
 };
 
+struct Trivial {
+  int i;
+};
+
 void cfunc(void (^ _Nonnull block)(NonTrivial)) noexcept {
   block(NonTrivial());
 }
@@ -45,4 +49,43 @@ void cfuncARCWeak(ARCWeak) noexcept;
 void (* _Nonnull getFnPtr() noexcept)(NonTrivial) noexcept;
 void (* _Nonnull getFnPtr2() noexcept)(ARCWeak) noexcept;
 
+class SharedRef {
+public:
+  static SharedRef *_Nonnull makeSharedRef() { return new SharedRef(); }
+  int _refCount = 1;
+
+private:
+  SharedRef() = default;
+
+  SharedRef(const SharedRef &other) = delete;
+  SharedRef &operator=(const SharedRef &other) = delete;
+  SharedRef(SharedRef &&other) = delete;
+  SharedRef &operator=(SharedRef &&other) = delete;
+} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retainSharedRef")))
+__attribute__((swift_attr("release:releaseSharedRef")));
+
+inline void
+cppGo(void (*_Nonnull takeConstSharedRef)(const SharedRef *_Nonnull x)) {
+  SharedRef *ref = SharedRef::makeSharedRef();
+  takeConstSharedRef(ref);
+}
+
+inline void retainSharedRef(SharedRef *_Nonnull x) { x->_refCount += 1; }
+inline void releaseSharedRef(SharedRef *_Nonnull x) {
+  x->_refCount -= 1;
+  if (x->_refCount == 0) {
+    delete x;
+  }
+}
+
+void cfuncConstRefNonTrivial(void (*_Nonnull)(const NonTrivial &));
+void cfuncConstRefTrivial(void (*_Nonnull)(const Trivial &));
+void blockConstRefNonTrivial(void (^_Nonnull)(const NonTrivial &));
+void blockConstRefTrivial(void (^_Nonnull)(const Trivial &));
+#if __OBJC__
+void cfuncConstRefStrong(void (*_Nonnull)(const ARCStrong &));
+void blockConstRefStrong(void (^_Nonnull)(const ARCStrong &));
+#endif
+
 #endif // __CLOSURE__
diff --git a/test/Interop/Cxx/class/Inputs/conforms-to.h b/test/Interop/Cxx/class/Inputs/conforms-to.h
index d0f612a9546c5..765270f68170d 100644
--- a/test/Interop/Cxx/class/Inputs/conforms-to.h
+++ b/test/Interop/Cxx/class/Inputs/conforms-to.h
@@ -16,6 +16,13 @@ struct
   void play() const;
 };
 
+struct __attribute__((swift_attr("conforms_to:SwiftTest.Testable")))
+__attribute__((swift_attr(
+    "conforms_to:SwiftTest.Playable"))) MultipleConformanceHasTestAndPlay {
+  void test() const;
+  void play() const;
+};
+
 struct
     __attribute__((swift_attr("conforms_to:ImportedModule.ProtocolFromImportedModule")))
     HasImportedConf {
@@ -24,6 +31,8 @@ struct
 
 struct DerivedFromHasTest : HasTest {};
 struct DerivedFromDerivedFromHasTest : HasTest {};
+struct DerivedFromMultipleConformanceHasTestAndPlay
+    : MultipleConformanceHasTestAndPlay {};
 
 struct __attribute__((swift_attr("conforms_to:SwiftTest.Testable")))
 DerivedFromDerivedFromHasTestWithDuplicateArg : HasTest {};
diff --git a/test/Interop/Cxx/class/Inputs/constructors.h b/test/Interop/Cxx/class/Inputs/constructors.h
index b584181fdcfec..791e542aec514 100644
--- a/test/Interop/Cxx/class/Inputs/constructors.h
+++ b/test/Interop/Cxx/class/Inputs/constructors.h
@@ -255,22 +255,22 @@ __attribute__((swift_attr("release:Release4"))) PlacementOperatorNew {
 
 struct __attribute__((swift_attr("import_reference")))
 __attribute__((swift_attr("retain:Retain5")))
-__attribute__((swift_attr("release:Release5"))) PrivateOperatorNew { // expected-error {{'operator new' is a private member of 'SwiftInitSynthesisForCXXRefTypes::PrivateOperatorNew}}
+__attribute__((swift_attr("release:Release5"))) PrivateOperatorNew {
 public:
   int val = 1;
 
 private:
-  void *operator new(size_t); // expected-note {{declared private here}}
+  void *operator new(size_t);
 };
 
 struct __attribute__((swift_attr("import_reference")))
 __attribute__((swift_attr("retain:Retain6")))
-__attribute__((swift_attr("release:Release6"))) ProtectedOperatorNew { // expected-error {{'operator new' is a protected member of 'SwiftInitSynthesisForCXXRefTypes::ProtectedOperatorNew'}}
+__attribute__((swift_attr("release:Release6"))) ProtectedOperatorNew {
 public:
   int val = 1;
 
 protected:
-  void *operator new(size_t); // expected-note {{declared protected here}}
+  void *operator new(size_t);
 };
 
 struct __attribute__((swift_attr("import_reference")))
@@ -337,52 +337,140 @@ __attribute__((swift_attr("release:Release14"))) ParameterizedCtor {
   int val = 1;
   ParameterizedCtor(int x) : val(x) {}
 };
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:Retain16")))
+__attribute__((swift_attr("release:Release16"))) ParameterizedCtor2 {
+public:
+  int val1 = 1;
+  int val2 = 1;
+  ParameterizedCtor2() {}
+  ParameterizedCtor2(int x) : val1(x) {}
+  ParameterizedCtor2(int x, int y) : val1(x), val2(y) {}
+};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:Retain17")))
+__attribute__((swift_attr("release:Release17"))) VariadicCtors {
+public:
+  int val1 = 1;
+  int val2 = 2;
+  VariadicCtors(...) {}
+};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:Retain18")))
+__attribute__((swift_attr("release:Release18"))) NoIdentifierInCtorParam {
+public:
+  int val = 10;
+  NoIdentifierInCtorParam(int) {}
+};
+
+struct cxxValTy {
+public:
+  int val;
+  cxxValTy() {}
+  cxxValTy(int x) { val = x; }
+  ~cxxValTy() {}
+};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:Retain20")))
+__attribute__((swift_attr("release:Release20"))) RValRefCtor2 {
+public:
+  cxxValTy val;
+  RValRefCtor2(cxxValTy &&x) { val = x; }
+};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:Retain21")))
+__attribute__((swift_attr("release:Release21"))) UserDefinedCopyCtor {
+public:
+  int val = 1;
+  UserDefinedCopyCtor(int x) { val = x; };
+
+  // User defined copy ctor
+  UserDefinedCopyCtor(const UserDefinedCopyCtor &other) { val = other.val; }
+};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:Retain22")))
+__attribute__((swift_attr("release:Release22"))) UserDefinedMoveCtor {
+public:
+  int val = 1;
+  UserDefinedMoveCtor(int x) { val = x; };
+
+  // User defined move constructor
+  UserDefinedMoveCtor(UserDefinedMoveCtor &&other) noexcept {
+    val = other.val;
+    other.val = -1;
+  }
+};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:Retain23")))
+__attribute__((swift_attr("release:Release23"))) UserDefinedMoveAndCopyCtor {
+public:
+  int val = 1;
+  UserDefinedMoveAndCopyCtor(int x) { val = x; };
+
+  // User defined copy ctor
+  UserDefinedMoveAndCopyCtor(const UserDefinedMoveAndCopyCtor &other) {
+    val = other.val;
+  }
+
+  // User defined move constructor
+  UserDefinedMoveAndCopyCtor(UserDefinedMoveAndCopyCtor &&other) noexcept {
+    val = other.val;
+    other.val = -1;
+  }
+};
 } // namespace SwiftInitSynthesisForCXXRefTypes
 
 void Retain1(SwiftInitSynthesisForCXXRefTypes::CompilerGeneratedDefaultCtor
-                  *_Nonnull v) {};
+                 *_Nonnull v) {}
 void Release1(SwiftInitSynthesisForCXXRefTypes::CompilerGeneratedDefaultCtor
-                  *_Nonnull v) {};
+                  *_Nonnull v) {}
 void Retain2(
-    SwiftInitSynthesisForCXXRefTypes::UserProvidedDefaultCtor *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::UserProvidedDefaultCtor *_Nonnull v) {}
 void Release2(
-    SwiftInitSynthesisForCXXRefTypes::UserProvidedDefaultCtor *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::UserProvidedDefaultCtor *_Nonnull v) {}
 void Retain3(
     SwiftInitSynthesisForCXXRefTypes::ExplicitCompilerGeneratedDefaultCtor
-        *_Nonnull v) {};
+        *_Nonnull v) {}
 void Release3(
     SwiftInitSynthesisForCXXRefTypes::ExplicitCompilerGeneratedDefaultCtor
-        *_Nonnull v) {};
+        *_Nonnull v) {}
 void Retain4(
-    SwiftInitSynthesisForCXXRefTypes::PlacementOperatorNew *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::PlacementOperatorNew *_Nonnull v) {}
 void Release4(
-    SwiftInitSynthesisForCXXRefTypes::PlacementOperatorNew *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::PlacementOperatorNew *_Nonnull v) {}
 void Retain5(SwiftInitSynthesisForCXXRefTypes::PrivateOperatorNew *_Nonnull v) {
 };
 void Release5(
-    SwiftInitSynthesisForCXXRefTypes::PrivateOperatorNew *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::PrivateOperatorNew *_Nonnull v) {}
 void Retain6(
-    SwiftInitSynthesisForCXXRefTypes::ProtectedOperatorNew *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::ProtectedOperatorNew *_Nonnull v) {}
 void Release6(
-    SwiftInitSynthesisForCXXRefTypes::ProtectedOperatorNew *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::ProtectedOperatorNew *_Nonnull v) {}
 void Retain7(SwiftInitSynthesisForCXXRefTypes::DeletedOperatorNew *_Nonnull v) {
 };
 void Release7(
-    SwiftInitSynthesisForCXXRefTypes::DeletedOperatorNew *_Nonnull v) {};
-void Retain8(SwiftInitSynthesisForCXXRefTypes::PrivateCtor *_Nonnull v) {};
-void Release8(SwiftInitSynthesisForCXXRefTypes::PrivateCtor *_Nonnull v) {};
-void Retain9(SwiftInitSynthesisForCXXRefTypes::ProtectedCtor *_Nonnull v) {};
-void Release9(SwiftInitSynthesisForCXXRefTypes::ProtectedCtor *_Nonnull v) {};
-void Retain10(SwiftInitSynthesisForCXXRefTypes::DeletedCtor *_Nonnull v) {};
-void Release10(SwiftInitSynthesisForCXXRefTypes::DeletedCtor *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::DeletedOperatorNew *_Nonnull v) {}
+void Retain8(SwiftInitSynthesisForCXXRefTypes::PrivateCtor *_Nonnull v) {}
+void Release8(SwiftInitSynthesisForCXXRefTypes::PrivateCtor *_Nonnull v) {}
+void Retain9(SwiftInitSynthesisForCXXRefTypes::ProtectedCtor *_Nonnull v) {}
+void Release9(SwiftInitSynthesisForCXXRefTypes::ProtectedCtor *_Nonnull v) {}
+void Retain10(SwiftInitSynthesisForCXXRefTypes::DeletedCtor *_Nonnull v) {}
+void Release10(SwiftInitSynthesisForCXXRefTypes::DeletedCtor *_Nonnull v) {}
 void Retain11(
-    SwiftInitSynthesisForCXXRefTypes::CtorWithDefaultArg *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::CtorWithDefaultArg *_Nonnull v) {}
 void Release11(
-    SwiftInitSynthesisForCXXRefTypes::CtorWithDefaultArg *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::CtorWithDefaultArg *_Nonnull v) {}
 void Retain12(SwiftInitSynthesisForCXXRefTypes::CtorWithDefaultAndNonDefaultArg
-                  *_Nonnull v) {};
+                  *_Nonnull v) {}
 void Release12(SwiftInitSynthesisForCXXRefTypes::CtorWithDefaultAndNonDefaultArg
-                    *_Nonnull v) {};
+                   *_Nonnull v) {}
 void Retain13(
     SwiftInitSynthesisForCXXRefTypes::DefaulltAndNonDefaultCtors *_Nonnull v) {
 };
@@ -392,10 +480,36 @@ void Release13(
 void Retain14(SwiftInitSynthesisForCXXRefTypes::ParameterizedCtor *_Nonnull v) {
 };
 void Release14(
-    SwiftInitSynthesisForCXXRefTypes::ParameterizedCtor *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::ParameterizedCtor *_Nonnull v) {}
 void Retain15(
-    SwiftInitSynthesisForCXXRefTypes::UserProvidedStaticFactory *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::UserProvidedStaticFactory *_Nonnull v) {}
 void Release15(
-    SwiftInitSynthesisForCXXRefTypes::UserProvidedStaticFactory *_Nonnull v) {};
+    SwiftInitSynthesisForCXXRefTypes::UserProvidedStaticFactory *_Nonnull v) {}
+void Retain16(
+    SwiftInitSynthesisForCXXRefTypes::ParameterizedCtor2 *_Nonnull v) {}
+void Release16(
+    SwiftInitSynthesisForCXXRefTypes::ParameterizedCtor2 *_Nonnull v) {}
+void Retain17(SwiftInitSynthesisForCXXRefTypes::VariadicCtors *_Nonnull v) {}
+void Release17(SwiftInitSynthesisForCXXRefTypes::VariadicCtors *_Nonnull v) {}
+void Retain18(
+    SwiftInitSynthesisForCXXRefTypes::NoIdentifierInCtorParam *_Nonnull v) {}
+void Release18(
+    SwiftInitSynthesisForCXXRefTypes::NoIdentifierInCtorParam *_Nonnull v) {}
+void Retain20(SwiftInitSynthesisForCXXRefTypes::RValRefCtor2 *_Nonnull v) {}
+void Release20(SwiftInitSynthesisForCXXRefTypes::RValRefCtor2 *_Nonnull v) {}
+void Retain21(
+    SwiftInitSynthesisForCXXRefTypes::UserDefinedCopyCtor *_Nonnull v) {}
+void Release21(
+    SwiftInitSynthesisForCXXRefTypes::UserDefinedCopyCtor *_Nonnull v) {}
+void Retain22(
+    SwiftInitSynthesisForCXXRefTypes::UserDefinedMoveCtor *_Nonnull v) {}
+void Release22(
+    SwiftInitSynthesisForCXXRefTypes::UserDefinedMoveCtor *_Nonnull v) {}
+void Retain23(
+    SwiftInitSynthesisForCXXRefTypes::UserDefinedMoveAndCopyCtor *_Nonnull v) {
+};
+void Release23(
+    SwiftInitSynthesisForCXXRefTypes::UserDefinedMoveAndCopyCtor *_Nonnull v) {
+};
 
 #endif // TEST_INTEROP_CXX_CLASS_INPUTS_CONSTRUCTORS_H
diff --git a/test/Interop/Cxx/class/Inputs/member-variables.h b/test/Interop/Cxx/class/Inputs/member-variables.h
index 526920c3ac339..198ab68913540 100644
--- a/test/Interop/Cxx/class/Inputs/member-variables.h
+++ b/test/Interop/Cxx/class/Inputs/member-variables.h
@@ -1,6 +1,10 @@
 #ifndef TEST_INTEROP_CXX_CLASS_INPUTS_MEMBER_VARIABLES_H
 #define TEST_INTEROP_CXX_CLASS_INPUTS_MEMBER_VARIABLES_H
 
+#include <cstddef>
+#include <type_traits>
+#include <optional>
+
 class MyClass {
 public:
   const int const_member = 23;
@@ -24,8 +28,76 @@ struct HasZeroSizedField {
   void set_c(short c) { this->c = c; }
 };
 
+struct ReuseOptionalFieldPadding {
+  [[no_unique_address]] std::optional<int> a = {2};
+  char c;
+  char get_c() const { return c; }
+  void set_c(char c) { this->c = c; }
+  int offset() const { return offsetof(ReuseOptionalFieldPadding, c); }
+  std::optional<int> getOptional() { return a; }
+};
+
+using OptInt = std::optional<int>;
+
+struct ReuseOptionalFieldPaddingWithTypedef {
+  [[no_unique_address]] OptInt a;
+  char c;
+  char get_c() const { return c; }
+  void set_c(char c) { this->c = c; }
+  int offset() const { return offsetof(ReuseOptionalFieldPadding, c); }
+};
+
+// Using a mix of private and public fields prevents this class from being
+// standard-layout, which is necessary to allow clang to reuse its padding.
+template<typename T>
+struct NonStandardLayoutClass {
+private:
+  T x;
+public:
+  char pad_me;
+};
+static_assert(std::is_standard_layout_v<NonStandardLayoutClass<int>> == false);
+
+struct ReuseNonStandardLayoutFieldPadding {
+  [[no_unique_address]] NonStandardLayoutClass<int> a;
+  char c;
+  char get_c() const { return c; }
+  void set_c(char c) { this->c = c; }
+  // C-style implementation of offsetof() to avoid non-standard-layout warning
+  int offset() const { return (char *) &this->c - (char *) this; }
+};
+
+template<typename T>
+struct ReuseDependentFieldPadding {
+  [[no_unique_address]] struct { private: T x; public: char pad_me; } a;
+  char c;
+  char get_c() const { return c; }
+  void set_c(char c) { this->c = c; }
+  // C-style implementation of offsetof() to avoid non-standard-layout warning
+  int offset() const { return (char *) &this->c - (char *) this; }
+};
+
+typedef ReuseDependentFieldPadding<int> ReuseDependentFieldPaddingInt;
+
 inline int takesZeroSizedInCpp(HasZeroSizedField x) {
   return x.a;
 }
 
+/// Not imported into Swift.
+struct EmptyNotImported {
+  char : 0;
+
+  EmptyNotImported() = default;
+  EmptyNotImported(const EmptyNotImported &) = delete;
+  EmptyNotImported(EmptyNotImported &&) = delete;
+};
+
+struct LastFieldNoUniqueAddress {
+  char c;
+  [[no_unique_address]] EmptyNotImported p0;
+
+  LastFieldNoUniqueAddress(const LastFieldNoUniqueAddress &other) {}
+  LastFieldNoUniqueAddress(LastFieldNoUniqueAddress &&other) {}
+};
+
 #endif
diff --git a/test/Interop/Cxx/class/Inputs/mirror.h b/test/Interop/Cxx/class/Inputs/mirror.h
new file mode 100644
index 0000000000000..8d12ee09c8f5d
--- /dev/null
+++ b/test/Interop/Cxx/class/Inputs/mirror.h
@@ -0,0 +1,49 @@
+#ifndef TEST_INTEROP_CXX_METADATA_INPUTS_MIRROR_H
+#define TEST_INTEROP_CXX_METADATA_INPUTS_MIRROR_H
+
+struct EmptyStruct {};
+
+struct BaseStruct {
+private:
+  int priv;
+
+public:
+  int publ;
+
+protected:
+  int prot;
+
+public:
+  BaseStruct(int i1, int i2, int i3) : priv(i1), publ(i2), prot(i3) {}
+};
+
+class EmptyClass {};
+
+struct OuterStruct {
+private:
+  BaseStruct privStruct;
+
+public:
+  BaseStruct publStruct;
+
+  OuterStruct() : privStruct(1, 2, 3), publStruct(4, 5, 6) {}
+};
+
+struct FRTStruct {
+private:
+  int priv = 1;
+
+public:
+  int publ = 2;
+} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retain")))
+__attribute__((swift_attr("release:release")));
+
+void retain(FRTStruct *v) {};
+void release(FRTStruct *v) {};
+
+class FRTImmortalClass {} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:immortal")))
+__attribute__((swift_attr("release:immortal")));
+
+#endif
diff --git a/test/Interop/Cxx/class/Inputs/module.modulemap b/test/Interop/Cxx/class/Inputs/module.modulemap
index fca54e3ce2814..ab8bb3e04e78c 100644
--- a/test/Interop/Cxx/class/Inputs/module.modulemap
+++ b/test/Interop/Cxx/class/Inputs/module.modulemap
@@ -152,3 +152,15 @@ module PIMPL {
   requires cplusplus
   export *
 }
+
+module SimpleStructs {
+  header "simple-structs.h"
+  requires cplusplus
+  export *
+}
+
+module Mirror {
+  header "mirror.h"
+  requires cplusplus
+  export *
+}
diff --git a/test/Interop/Cxx/class/Inputs/simple-structs.h b/test/Interop/Cxx/class/Inputs/simple-structs.h
new file mode 100644
index 0000000000000..c8f84b4e7eea2
--- /dev/null
+++ b/test/Interop/Cxx/class/Inputs/simple-structs.h
@@ -0,0 +1,64 @@
+#ifndef TEST_INTEROP_CXX_CLASS_INPUTS_SIMPLE_STRUCTS_H
+#define TEST_INTEROP_CXX_CLASS_INPUTS_SIMPLE_STRUCTS_H
+
+struct HasPrivateFieldsOnly {
+private:
+  int priv1;
+  int priv2;
+
+public:
+  HasPrivateFieldsOnly(int i1, int i2) : priv1(i1), priv2(i2) {}
+};
+
+struct HasPublicFieldsOnly {
+  int publ1;
+  int publ2;
+
+  HasPublicFieldsOnly(int i1, int i2) : publ1(i1), publ2(i2) {}
+};
+
+struct HasAnonymousType {
+  HasAnonymousType(int a, int b, int c) : a(a), b(b), c(c) {}
+
+  struct {
+    int a, b;
+  };
+  int c;
+};
+
+struct HasPrivatePublicProtectedFields {
+private:
+  int priv1;
+
+public:
+  int publ1;
+
+protected:
+  int prot1;
+
+protected:
+  int prot2;
+
+private:
+  int priv2;
+
+public:
+  int publ2;
+
+  HasPrivatePublicProtectedFields(int i1, int i2, int i3, int i4, int i5,
+                                  int i6)
+      : priv1(i1), publ1(i2), prot1(i3), prot2(i4), priv2(i5),
+        publ2(i6) {}
+};
+
+struct Outer {
+private:
+  HasPrivatePublicProtectedFields privStruct;
+
+public:
+  HasPrivatePublicProtectedFields publStruct;
+
+  Outer() : privStruct(1, 2, 3, 4, 5, 6), publStruct(7, 8, 9, 10, 11, 12) {}
+};
+
+#endif
diff --git a/test/Interop/Cxx/class/access-anonymous-field.swift b/test/Interop/Cxx/class/access-anonymous-field.swift
new file mode 100644
index 0000000000000..133956fb87e72
--- /dev/null
+++ b/test/Interop/Cxx/class/access-anonymous-field.swift
@@ -0,0 +1,12 @@
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -swift-version 6 -cxx-interoperability-mode=upcoming-swift
+
+// CHECK: Foobar
+
+import SimpleStructs
+
+let s = HasAnonymousType(1, 2, 3)
+let _ = s.__Anonymous_field0 // expected-error {{'__Anonymous_field0' is unavailable: refer to the members of the anonymous type instead}}
+// Referring to the members of the anonymous type directly.
+let _ = s.a
+let _ = s.b
+let _ = s.c
diff --git a/test/Interop/Cxx/class/access/Inputs/non-public.h b/test/Interop/Cxx/class/access/Inputs/non-public.h
index e32bd1738a702..3fc9626796fba 100644
--- a/test/Interop/Cxx/class/access/Inputs/non-public.h
+++ b/test/Interop/Cxx/class/access/Inputs/non-public.h
@@ -21,15 +21,26 @@ __attribute__((__swift_attr__("private_fileid:main/blessed.swift"))) MyClass {
   void publMethod(void) const {}
   void publMutatingMethod(void) {}
   int publVar;
-  static void publStaticFunc(void);
-  static int publStaticVar;
+  static void publStaticFunc(void) {};
+  static inline int publStaticVar = 0;
 
   typedef int publTypedef;
-  struct publStruct {};
+  publTypedef publTypedefMake(void) const { return 42; }
+  void publTypedefTake(publTypedef x) const { }
+
+  struct publStruct { int x; };
+  publStruct publStructMake(void) const { return publStruct{}; }
+  void publStructTake(publStruct x) const { }
 
   enum publEnum { variantPublEnum };
-  enum { publEnumAnonValue1 };
+  publEnum publEnumMake(void) const { return variantPublEnum; }
+  void publEnumTake(publEnum x) const { }
+
   enum class publEnumClass { variantPublEnumClass };
+  publEnumClass publEnumClassMake(void) const { return publEnumClass::variantPublEnumClass; }
+  void publEnumClassTake(publEnumClass x) const { }
+
+  enum { publEnumAnonValue1 };
   enum publEnumClosed {
     variantPublEnumClosed
   } __attribute__((enum_extensibility(closed)));
@@ -42,15 +53,26 @@ __attribute__((__swift_attr__("private_fileid:main/blessed.swift"))) MyClass {
   void privMethod(void) const {}
   void privMutatingMethod(void) {}
   int privVar;
-  static void privStaticFunc(void);
-  static int privStaticVar;
+  static void privStaticFunc(void) {};
+  static inline int privStaticVar = 0;
 
   typedef int privTypedef;
-  struct privStruct {};
+  privTypedef privTypedefMake(void) const { return 42; }
+  void privTypedefTake(privTypedef x) const { }
+
+  struct privStruct { int x; };
+  privStruct privStructMake(void) const { return privStruct{}; }
+  void privStructTake(privStruct x) const { }
 
   enum privEnum { variantPrivEnum };
-  enum { privEnumAnonValue1 };
+  privEnum privEnumMake(void) const { return variantPrivEnum; }
+  void privEnumTake(privEnum x) const { }
+
   enum class privEnumClass { variantPrivEnumClass };
+  privEnumClass privEnumClassMake(void) const { return privEnumClass::variantPrivEnumClass; }
+  void privEnumClassTake(privEnumClass x) const { }
+
+  enum { privEnumAnonValue1 };
   enum privEnumClosed {
     variantPrivEnumClosed
   } __attribute__((enum_extensibility(closed)));
diff --git a/test/Interop/Cxx/class/access/access-inversion-executable.swift b/test/Interop/Cxx/class/access/access-inversion-executable.swift
index 175afde0997bc..9d686e1e32b16 100644
--- a/test/Interop/Cxx/class/access/access-inversion-executable.swift
+++ b/test/Interop/Cxx/class/access/access-inversion-executable.swift
@@ -28,7 +28,7 @@ AccessInversionTestSuite.test("usePrivateRec") {
 }
 
 AccessInversionTestSuite.test("usePrivateEnum") {
-    let e = Leaky.AliasToPrivateEnum(rawValue: 0)!
+    let e = Leaky.AliasToPrivateEnum(rawValue: 0)
     expectEqual(e.rawValue, 0)
 }
 
diff --git a/test/Interop/Cxx/class/access/access-inversion-module-interface.swift b/test/Interop/Cxx/class/access/access-inversion-module-interface.swift
index f3691bf83ab83..986d0791870bd 100644
--- a/test/Interop/Cxx/class/access/access-inversion-module-interface.swift
+++ b/test/Interop/Cxx/class/access/access-inversion-module-interface.swift
@@ -9,7 +9,7 @@
 // CHECK:     public init()
 // CHECK:     private init()
 // CHECK:     public func privateRecMethod()
-// CHECK:     public static let PRIVATE_REC_CONST: Bool
+// CHECK:     public static var PRIVATE_REC_CONST: Bool { get }
 // CHECK:   }
 
 // CHECK:   private struct PrivateEnum : Hashable, Equatable, RawRepresentable {
@@ -26,7 +26,7 @@
 // CHECK:     case privateEnumClassMember
 // CHECK:   }
 
-// CHECK:   private static let PRIVATE_CONST: Bool
+// CHECK:   private static var PRIVATE_CONST: Bool { get }
 
 // CHECK:   private static var privateAliasVal: Leaky.PrivateAlias
 // CHECK:   private static var privateRecVal: Leaky.PrivateRec
diff --git a/test/Interop/Cxx/class/access/access-inversion-typechecker.swift b/test/Interop/Cxx/class/access/access-inversion-typechecker.swift
index 4159abde52d80..ae361132ddb34 100644
--- a/test/Interop/Cxx/class/access/access-inversion-typechecker.swift
+++ b/test/Interop/Cxx/class/access/access-inversion-typechecker.swift
@@ -4,7 +4,7 @@
 // but does not necessarily specify it (in the deliberate sense). In other words,
 // there may be behaviors captured in these tests that deserve amending.
 
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
 // REQUIRES: swift_feature_ImportNonPublicCxxMembers
 
 import AccessInversion
@@ -208,10 +208,10 @@ func usePrivateEnum(a: inout Leaky.AliasToPrivateEnum) -> Leaky.AliasToPrivateEn
     // Constructing and reading PrivateEnum
     //
 
-    // TODO: nested enum members are not being imported (#54905)
-    // let _ = Leaky.privateEnumMember
-    let rv0 = Leaky.AliasToPrivateEnum(rawValue: 0)!
-    let _ = Leaky.PrivateEnum(rawValue: 0)!
+    let _ = Leaky.privateEnumMember // FIXME: nested enum members are not being imported (#54905)
+    // expected-error@-1 {{type 'Leaky' has no member 'privateEnumMember'}}
+    let rv0 = Leaky.AliasToPrivateEnum(rawValue: 0)
+    let _ = Leaky.PrivateEnum(rawValue: 0)
     // expected-error@-1 {{'PrivateEnum' is inaccessible due to 'private' protection level}}
 
     let _ = rv0.rawValue
@@ -276,16 +276,13 @@ func usePrivateEnumClass(a: inout Leaky.AliasToPrivateEnumClass) -> Leaky.AliasT
     // Constructing and reading PrivateEnumClass
     //
 
-    // NOTE: private enum class members are not accessible even if we can access
-    // instances of the private enum class via
+    // NOTE: private enum class members are accessible if we can access
+    // their parent enum class decl
 
     let _ = Leaky.AliasToPrivateEnumClass.privateEnumClassMember
-    // expected-error@-1 {{'privateEnumClassMember' is inaccessible due to 'private' protection level}}
     let _ = Leaky.PrivateEnumClass.privateEnumClassMember
     // expected-error@-1 {{'PrivateEnumClass' is inaccessible due to 'private' protection level}}
-    let _: Leaky.AliasToPrivateEnum = .privateEnumClassMember
-    // expected-error@-1 {{type 'Leaky.AliasToPrivateEnum' (aka 'Leaky.PrivateEnum') has no member 'privateEnumClassMember'}}
-    // TODO: ^this is not really the right error message
+    let _: Leaky.AliasToPrivateEnumClass = .privateEnumClassMember
 
     let rv0 = Leaky.AliasToPrivateEnumClass(rawValue: 0)!
     let _ = Leaky.PrivateEnumClass(rawValue: 0)!
@@ -298,7 +295,6 @@ func usePrivateEnumClass(a: inout Leaky.AliasToPrivateEnumClass) -> Leaky.AliasT
 
     switch rv0 {
     case .privateEnumClassMember:
-    // expected-error@-1 {{'privateEnumClassMember' is inaccessible due to 'private' protection level}}
       doSomething()
     default:
       doSomething()
diff --git a/test/Interop/Cxx/class/access/access-specifiers-typechecker.swift b/test/Interop/Cxx/class/access/access-specifiers-typechecker.swift
index 030babd16503a..b5b62eeebdb0b 100644
--- a/test/Interop/Cxx/class/access/access-specifiers-typechecker.swift
+++ b/test/Interop/Cxx/class/access/access-specifiers-typechecker.swift
@@ -1,6 +1,6 @@
 // Test that C++ access specifiers are honored.
 
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -enable-experimental-cxx-interop -enable-experimental-feature ImportNonPublicCxxMembers
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -enable-experimental-cxx-interop -enable-experimental-feature ImportNonPublicCxxMembers
 // REQUIRES: swift_feature_ImportNonPublicCxxMembers
 
 import AccessSpecifiers
diff --git a/test/Interop/Cxx/class/access/non-public-inheritance-typecheck.swift b/test/Interop/Cxx/class/access/non-public-inheritance-typecheck.swift
index 36ba1c566c64e..492b781f676f7 100644
--- a/test/Interop/Cxx/class/access/non-public-inheritance-typecheck.swift
+++ b/test/Interop/Cxx/class/access/non-public-inheritance-typecheck.swift
@@ -1,6 +1,6 @@
 //--- blessed.swift
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift
 import NonPublicInheritance
 
 // Extensions of each class test whether we correctly modeled *which* members
diff --git a/test/Interop/Cxx/class/access/non-public-nested-enum-executable.swift b/test/Interop/Cxx/class/access/non-public-nested-enum-executable.swift
new file mode 100644
index 0000000000000..0cfcedfd3b627
--- /dev/null
+++ b/test/Interop/Cxx/class/access/non-public-nested-enum-executable.swift
@@ -0,0 +1,111 @@
+// RUN: split-file %s %t
+
+// RUN: %target-build-swift -module-name main %t/base.swift -I %t/Inputs -o %t/base -Xfrontend -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
+// RUN: %target-codesign %t/base
+// RUN: %target-run %t/base
+
+// RUN: %target-build-swift -module-name main %t/not-base.swift -I %t/Inputs -o %t/not-base -Xfrontend -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
+// RUN: %target-codesign %t/not-base
+// RUN: %target-run %t/not-base
+
+// RUN: %target-build-swift -module-name main %t/derived.swift -I %t/Inputs -o %t/derived -Xfrontend -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
+// RUN: %target-codesign %t/derived
+// RUN: %target-run %t/derived
+
+// RUN: %target-build-swift -module-name main %t/not-derived.swift -I %t/Inputs -o %t/not-derived -Xfrontend -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
+// RUN: %target-codesign %t/not-derived
+// RUN: %target-run %t/not-derived
+
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_ImportNonPublicCxxMembers
+
+//--- Inputs/module.modulemap
+module CxxModule {
+    requires cplusplus
+    header "cxx-header.h"
+}
+
+//--- Inputs/cxx-header.h
+#pragma once
+
+class __attribute__((__swift_attr__("private_fileid:main/base.swift")))
+Base {
+protected:
+  enum class Enum { Foo, Bar };
+public:
+  Enum makeEnum(void) const { return Enum::Bar; }
+};
+
+class __attribute__((__swift_attr__("private_fileid:main/derived.swift")))
+Derived : public Base {};
+
+//--- base.swift
+import StdlibUnittest
+import CxxModule
+
+var Suite = TestSuite("BlessedForBase")
+extension Base {
+  static func makeEnums() {
+    let e1: Enum = Enum.Bar
+    let e2: Enum = Enum.Foo
+    expectEqual(e1, Enum.Bar)
+    expectNotEqual(e1, e2)
+    switch e2 {
+    case .Bar:
+      expectTrue(false, "foo is bar")
+    case .Foo:
+      expectTrue(true, "foo is foo")
+    }
+  }
+}
+Suite.test("Use private nested enum in base class") { Base.makeEnums() }
+runAllTests()
+
+//--- not-base.swift
+import StdlibUnittest
+import CxxModule
+
+var Suite = TestSuite("NotBlessedForBase")
+Suite.test("Use private nested enum in base class") {
+  let b = Base()
+  let e1 = b.makeEnum()
+  let e2 = b.makeEnum()
+  expectEqual(e1, e2)
+}
+runAllTests()
+
+
+//--- derived.swift
+import StdlibUnittest
+import CxxModule
+
+var Suite = TestSuite("BlessedForDerived")
+extension Derived {
+  static func makeEnums() {
+    let e1: Enum = Enum.Bar
+    let e2: Enum = Enum.Foo
+    expectEqual(e1, Enum.Bar)
+    expectNotEqual(e1, e2)
+    switch e2 {
+    case .Bar:
+      expectTrue(false, "foo is bar")
+    case .Foo:
+      expectTrue(true, "foo is foo")
+    }
+  }
+}
+Suite.test("Use private nested enum inherited from base class") { Derived.makeEnums() }
+runAllTests()
+
+//--- not-derived.swift
+import StdlibUnittest
+import CxxModule
+
+var Suite = TestSuite("NotBlessedForDerive")
+Suite.test("Use private nested enum inherited from base class") {
+  let d = Derived()
+  let e1 = d.makeEnum()
+  let e2 = d.makeEnum()
+  expectEqual(e1, e2)
+}
+runAllTests()
diff --git a/test/Interop/Cxx/class/access/non-public-nested-enum-module-interface.swift b/test/Interop/Cxx/class/access/non-public-nested-enum-module-interface.swift
new file mode 100644
index 0000000000000..11cb0ee1bf902
--- /dev/null
+++ b/test/Interop/Cxx/class/access/non-public-nested-enum-module-interface.swift
@@ -0,0 +1,43 @@
+// RUN: split-file %s %t
+
+// RUN: %target-swift-ide-test -print-module -module-to-print=CxxModule -print-access -I %t/Inputs -source-filename=x -enable-experimental-cxx-interop -enable-experimental-feature ImportNonPublicCxxMembers | %FileCheck %s
+
+// REQUIRES: swift_feature_ImportNonPublicCxxMembers
+
+//--- Inputs/module.modulemap
+module CxxModule {
+    requires cplusplus
+    header "cxx-header.h"
+}
+
+//--- Inputs/cxx-header.h
+#pragma once
+
+class __attribute__((__swift_attr__("private_fileid:main/base.swift")))
+Base {
+protected:
+  enum class Enum { Foo, Bar };
+public:
+  Enum makeEnum(void) const { return Enum::Bar; }
+};
+
+class __attribute__((__swift_attr__("private_fileid:main/derived.swift")))
+Derived : public Base {};
+
+// CHECK:      public struct Base {
+// CHECK-NEXT:   public init()
+// CHECK-NEXT:   private enum Enum : [[ENUM_UNDERLYING_TYPE:Int32|UInt32]] {
+// CHECK-NEXT:     private init?(rawValue: [[ENUM_UNDERLYING_TYPE]])
+// CHECK-NEXT:     private var rawValue: [[ENUM_UNDERLYING_TYPE]] { get }
+// CHECK-NEXT:     private typealias RawValue = [[ENUM_UNDERLYING_TYPE]]
+// CHECK-NEXT:     case Foo
+// CHECK-NEXT:     case Bar
+// CHECK-NEXT:   }
+// CHECK-NEXT:   public func makeEnum() -> Base.Enum
+// CHECK-NEXT: }
+
+// CHECK-NEXT: public struct Derived {
+// CHECK-NEXT:   public init()
+// CHECK-NEXT:   private typealias Enum = Base.Enum
+// CHECK-NEXT:   public func makeEnum() -> Base.Enum
+// CHECK-NEXT: }
diff --git a/test/Interop/Cxx/class/access/non-public-nested-enum-typecheck.swift b/test/Interop/Cxx/class/access/non-public-nested-enum-typecheck.swift
new file mode 100644
index 0000000000000..b32e0c7c57695
--- /dev/null
+++ b/test/Interop/Cxx/class/access/non-public-nested-enum-typecheck.swift
@@ -0,0 +1,116 @@
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers -module-name main %t/base.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers -module-name main %t/derived.swift
+
+// REQUIRES: swift_feature_ImportNonPublicCxxMembers
+
+//--- Inputs/module.modulemap
+module CxxModule {
+    requires cplusplus
+    header "cxx-header.h"
+}
+
+//--- Inputs/cxx-header.h
+#pragma once
+
+class __attribute__((__swift_attr__("private_fileid:main/base.swift")))
+Base {
+protected:
+  enum class Enum { Foo, Bar };
+public:
+  Enum makeEnum(void) const { return Enum::Bar; }
+};
+
+class __attribute__((__swift_attr__("private_fileid:main/derived.swift")))
+Derived : public Base {};
+
+//--- base.swift
+import CxxModule
+
+extension Base {
+  private static func inside(e: Enum) {
+    let _: Enum = Enum.Bar
+    let _: Base.Enum = Base.Enum.Bar
+    let _: Enum = Base.Enum.Foo
+    let _: Base.Enum = Enum.Foo
+
+    switch e {
+      case .Bar: return
+      case .Foo: return
+    }
+  }
+}
+
+func switches() {
+  let b = Base()
+  let d = Derived()
+  switch b.makeEnum() {
+    default: return   // this is OK
+  }
+  switch d.makeEnum() {
+    default: return   // this is OK
+  }
+  switch b.makeEnum() {
+    case Base.Enum.Bar: return // expected-error {{'Enum' is inaccessible due to 'private' protection level}}
+    case Base.Enum.Foo: return // expected-error {{'Enum' is inaccessible due to 'private' protection level}}
+  }
+  switch b.makeEnum() {
+    case .Bar: return // OK as long as the user does not refer to Enum itself
+    case .Foo: return // (NOTE: arguably this should not be allowed)
+  }
+  switch d.makeEnum() {
+    case Derived.Enum.Bar: return // expected-error {{'Enum' is inaccessible due to 'private' protection level}}
+    case Derived.Enum.Foo: return // expected-error {{'Enum' is inaccessible due to 'private' protection level}}
+  }
+  switch d.makeEnum() {
+    case .Bar: return // OK as long as the user does not refer to Enum itself
+    case .Foo: return // (NOTE: arguably this should not be allowed)
+  }
+}
+
+func outside() {
+  let b = Base()
+  let d = Derived()
+  let _ = b.makeEnum()  // This is OK as long as we don't name the type
+  let _ = d.makeEnum()  // This is OK as long as we don't name the type
+
+  let _: Derived.Enum = b.makeEnum() // expected-error {{'Enum' is inaccessible due to 'private' protection level}}
+  let _: Derived.Enum = d.makeEnum() // expected-error {{'Enum' is inaccessible due to 'private' protection level}}
+
+  // The types in the base and derived types should be considered the same type
+  var x = b.makeEnum()
+  x = d.makeEnum()
+  var y = d.makeEnum()
+  y = b.makeEnum()
+}
+
+//--- derived.swift
+import CxxModule
+
+extension Base {
+  private static func inside(e: Enum) { // expected-error    {{'Enum' is inaccessible due to 'private' protection level}}
+    let _: Enum = Enum.Bar              // expected-error    {{'Enum' is inaccessible due to 'private' protection level}}
+                                        // expected-error@-1 {{'Enum' is inaccessible due to 'private' protection level}}
+  }
+}
+
+extension Derived {
+  private static func inside(e: Enum) {
+    let b = Base()
+    let _: Enum = Enum.Bar
+    let _: Derived.Enum = Derived.Enum.Bar
+    let _: Enum = b.makeEnum()
+
+    // It would be nice to make these work but they do not
+    let _: Base.Enum = Base.Enum.Bar // expected-error    {{'Enum' is inaccessible due to 'private' protection level}}
+                                     // expected-error@-1 {{'Enum' is inaccessible due to 'private' protection level}}
+    let _: Enum = Base.Enum.Foo      // expected-error    {{'Enum' is inaccessible due to 'private' protection level}}
+    let _: Base.Enum = Enum.Foo      // expected-error    {{'Enum' is inaccessible due to 'private' protection level}}
+
+    switch e {
+      case .Bar: return
+      case .Foo: return
+    }
+  }
+}
diff --git a/test/Interop/Cxx/class/access/non-public-shadow-typecheck.swift b/test/Interop/Cxx/class/access/non-public-shadow-typecheck.swift
index 428b2336ded33..41fa6dbcda6cd 100644
--- a/test/Interop/Cxx/class/access/non-public-shadow-typecheck.swift
+++ b/test/Interop/Cxx/class/access/non-public-shadow-typecheck.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend %s -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
+// RUN: %target-swift-frontend %s -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
 // REQUIRES: swift_feature_ImportNonPublicCxxMembers
 import NonPublicShadow
 
diff --git a/test/Interop/Cxx/class/access/private-fileid-conformance.swift b/test/Interop/Cxx/class/access/private-fileid-conformance.swift
new file mode 100644
index 0000000000000..b27d8d2926a51
--- /dev/null
+++ b/test/Interop/Cxx/class/access/private-fileid-conformance.swift
@@ -0,0 +1,53 @@
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t/Cxx/include %t/PrivateFile.swift -cxx-interoperability-mode=default -module-name Module
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t/Cxx/include %t/HasRetroactive.swift -cxx-interoperability-mode=default -module-name Module
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t/Cxx/include %t/NoRetroactive.swift -cxx-interoperability-mode=default -module-name Module
+
+//--- Cxx/include/module.modulemap
+module CxxModule {
+    requires cplusplus
+    header "cxx-header.h"
+}
+
+//--- Cxx/include/cxx-header.h
+#pragma once
+
+#define SWIFT_PRIVATE_FILEID(_fileID) \
+  __attribute__((swift_attr("private_fileid:" _fileID)))
+
+class SWIFT_PRIVATE_FILEID("Module/PrivateFile.swift") Foo { void privateMethod(void) const {} };
+
+//--- PrivateFile.swift
+import CxxModule
+
+extension Foo : ExpressibleByIntegerLiteral {
+    public typealias IntegerLiteralType = Int
+    public init(integerLiteral: Self.IntegerLiteralType) {
+        self.init()
+        self.privateMethod()
+    }
+}
+
+//--- HasRetroactive.swift
+import CxxModule
+
+extension Foo : @retroactive ExpressibleByIntegerLiteral {
+    public typealias IntegerLiteralType = Int
+    public init(integerLiteral: Self.IntegerLiteralType) {
+        self.init()
+        self.privateMethod() // expected-error {{'privateMethod' is inaccessible due to 'private' protection level}}
+    }
+}
+
+//--- NoRetroactive.swift
+import CxxModule
+
+// expected-warning@+2 {{extension declares a conformance of imported type 'Foo' to imported protocol 'ExpressibleByIntegerLiteral'}}
+// expected-note@+1 {{add '@retroactive' to silence this warning}}
+extension Foo : ExpressibleByIntegerLiteral {
+    public typealias IntegerLiteralType = Int
+    public init(integerLiteral: Self.IntegerLiteralType) {
+        self.init()
+        self.privateMethod() // expected-error {{'privateMethod' is inaccessible due to 'private' protection level}}
+    }
+}
diff --git a/test/Interop/Cxx/class/access/private-fileid-diagnostics.swift b/test/Interop/Cxx/class/access/private-fileid-diagnostics.swift
index a8e56d1a544f8..c046e4ef675d3 100644
--- a/test/Interop/Cxx/class/access/private-fileid-diagnostics.swift
+++ b/test/Interop/Cxx/class/access/private-fileid-diagnostics.swift
@@ -1,8 +1,5 @@
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend -typecheck -verify -suppress-remarks %t/some/subdir/file1.swift -verify-additional-file %t/Cxx/include/cxx-header.h -I %t/Cxx/include -cxx-interoperability-mode=default -module-name main
-
-// This test uses -verify-additional-file, which do not work well on Windows:
-// UNSUPPORTED: OS=windows-msvc
+// RUN: %target-swift-frontend -typecheck -verify -suppress-remarks %t%{fs-sep}some%{fs-sep}subdir%{fs-sep}file1.swift -verify-additional-file %t%{fs-sep}Cxx%{fs-sep}include%{fs-sep}cxx-header.h -I %t%{fs-sep}Cxx%{fs-sep}include -cxx-interoperability-mode=default -module-name main
 
 //--- Cxx/include/module.modulemap
 module CxxModule {
diff --git a/test/Interop/Cxx/class/access/private-fileid-irgen.swift b/test/Interop/Cxx/class/access/private-fileid-irgen.swift
new file mode 100644
index 0000000000000..d7c30f6c989ce
--- /dev/null
+++ b/test/Interop/Cxx/class/access/private-fileid-irgen.swift
@@ -0,0 +1,112 @@
+//--- blessed.swift
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -emit-ir -module-name main %t/blessed.swift -I %S/Inputs -cxx-interoperability-mode=default -Onone | %FileCheck %s
+// RUN: %target-swift-frontend -emit-ir -module-name main %t/blessed.swift -I %S/Inputs -cxx-interoperability-mode=default -Onone -g | %FileCheck %s
+
+import NonPublic
+
+// These extension methods are just here to make it clear what we are doing to
+// each Int32-typed member.
+extension Int32 {
+    func read() { }
+    mutating func write() { }
+}
+
+extension MyClass {
+    public func extMethod() {
+        publMethod()
+        privMethod()
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extMethod{{.*}}"
+// CHECK:   {{invoke|call}} void @{{.*}}publMethod{{.*}}
+// CHECK:   {{invoke|call}} void @{{.*}}privMethod{{.*}}
+
+    public mutating func extMutatingMethod() {
+        publMutatingMethod()
+        privMutatingMethod()
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extMutatingMethod{{.*}}"
+// CHECK:   {{invoke|call}} void @{{.*}}publMutatingMethod{{.*}}
+// CHECK:   {{invoke|call}} void @{{.*}}privMutatingMethod{{.*}}
+
+    public func extVarRead() {
+        publVar.read()
+        privVar.read()
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extVarRead{{.*}}"
+
+    public mutating func extVarWrite() {
+        publVar.write()
+        privVar.write()
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extVarWrite{{.*}}"
+
+    public func extStaticFunc() {
+        MyClass.publStaticFunc()
+        MyClass.privStaticFunc()
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extStaticFunc{{.*}}"
+// CHECK:   {{invoke|call}} void @{{.*}}publStaticFunc
+// CHECK:   {{invoke|call}} void @{{.*}}privStaticFunc
+
+    public func extStaticVarRead() {
+        MyClass.publStaticVar.read()
+        MyClass.privStaticVar.read()
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extStaticVarRead{{.*}}"
+
+    public func extStaticVarWrite() {
+        MyClass.publStaticVar.write()
+        MyClass.privStaticVar.write()
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extStaticVarWrite{{.*}}"
+
+    public func extTypedef() {
+      let u: publTypedef = publTypedefMake()
+      publTypedefTake(u)
+      let i: privTypedef = privTypedefMake()
+      privTypedefTake(i)
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extTypedef{{.*}}"
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}publTypedefMake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}publTypedefTake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}privTypedefMake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}privTypedefTake{{.*}}
+
+    public func extStruct() {
+      let u: publStruct = publStructMake()
+      publStructTake(u)
+      let i: privStruct = privStructMake()
+      privStructTake(i)
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extStruct{{.*}}"
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}publStructMake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}publStructTake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}privStructMake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}privStructTake{{.*}}
+
+    public func extEnum() {
+      let u: publEnum = publEnumMake()
+      publEnumTake(u)
+      let i: privEnum = privEnumMake()
+      privEnumTake(i)
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extEnum{{.*}}"
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}publEnumMake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}publEnumTake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}privEnumMake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}privEnumTake{{.*}}
+
+    // If we call this extEnumClass, the name gets mangled to something else.
+    public func extEnumCls() {
+      let u: publEnumClass = publEnumClassMake()
+      publEnumClassTake(u)
+      let i: privEnumClass = privEnumClassMake()
+      privEnumClassTake(i)
+    }
+// CHECK: define {{.*}}swiftcc void @"{{.*}}extEnumCls{{.*}}"
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}publEnumClassMake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}publEnumClassTake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}privEnumClassMake{{.*}}
+// CHECK:   {{invoke|call}} {{.*}} @{{.*}}privEnumClassTake{{.*}}
+}
diff --git a/test/Interop/Cxx/class/access/private-fileid-nested-typecheck.swift b/test/Interop/Cxx/class/access/private-fileid-nested-typecheck.swift
index 4ab68f874a93d..c91d08b24b59c 100644
--- a/test/Interop/Cxx/class/access/private-fileid-nested-typecheck.swift
+++ b/test/Interop/Cxx/class/access/private-fileid-nested-typecheck.swift
@@ -2,8 +2,8 @@
 // works as expected.
 //
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend -typecheck -verify %t/file1.swift -I %t/include -cxx-interoperability-mode=default -module-name main
-// RUN: %target-swift-frontend -typecheck -verify %t/file2.swift -I %t/include -cxx-interoperability-mode=default -module-name main
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/file1.swift -I %t/include -cxx-interoperability-mode=default -module-name main
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/file2.swift -I %t/include -cxx-interoperability-mode=default -module-name main
 
 //--- include/module.modulemap
 module CxxModule {
diff --git a/test/Interop/Cxx/class/access/private-fileid-template-typecheck.swift b/test/Interop/Cxx/class/access/private-fileid-template-typecheck.swift
index 23b4c6a04a029..f634bf21f03d1 100644
--- a/test/Interop/Cxx/class/access/private-fileid-template-typecheck.swift
+++ b/test/Interop/Cxx/class/access/private-fileid-template-typecheck.swift
@@ -15,7 +15,7 @@
 // non-public in different contexts, and variations in module and file names.
 //
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift
 
 //--- blessed.swift
 
diff --git a/test/Interop/Cxx/class/access/private-fileid-typecheck.swift b/test/Interop/Cxx/class/access/private-fileid-typecheck.swift
index 2e43f8e906167..d600373a5889e 100644
--- a/test/Interop/Cxx/class/access/private-fileid-typecheck.swift
+++ b/test/Interop/Cxx/class/access/private-fileid-typecheck.swift
@@ -16,37 +16,37 @@
 // members are private (default) or protected. The result should be the same
 // no matter the configuration.
 //
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift -Xcc -DTEST_CLASS=struct
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift -Xcc -DTEST_PRIVATE=protected
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift -Xcc -DTEST_CLASS=struct -Xcc -DTEST_PRIVATE=protected
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift -Xcc -DTEST_CLASS=struct
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift -Xcc -DTEST_PRIVATE=protected
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/blessed.swift -Xcc -DTEST_CLASS=struct -Xcc -DTEST_PRIVATE=protected
 //
 // This test also includes a "cursed.swift", which expects to not have access to
 // non-public members:
 //
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/cursed.swift
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/cursed.swift -Xcc -DTEST_CLASS=struct
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/cursed.swift -Xcc -DTEST_PRIVATE=protected
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/cursed.swift -Xcc -DTEST_CLASS=struct -Xcc -DTEST_PRIVATE=protected
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/cursed.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/cursed.swift -Xcc -DTEST_CLASS=struct
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/cursed.swift -Xcc -DTEST_PRIVATE=protected
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/cursed.swift -Xcc -DTEST_CLASS=struct -Xcc -DTEST_PRIVATE=protected
 //
 // To check that fileID is agnostic about directory structure within a module,
 // we move blessed.swift into a subdirectory (but keep its filename).
 //
 // RUN: mkdir -p %t/subdir/subsubdir
 // RUN: mv %t/blessed.swift %t/subdir/subsubdir/blessed.swift
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/subdir/subsubdir/blessed.swift
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/subdir/subsubdir/blessed.swift -Xcc -DTEST_CLASS=struct
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/subdir/subsubdir/blessed.swift -Xcc -DTEST_PRIVATE=protected
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/subdir/subsubdir/blessed.swift -Xcc -DTEST_CLASS=struct -Xcc -DTEST_PRIVATE=protected
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/subdir/subsubdir/blessed.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/subdir/subsubdir/blessed.swift -Xcc -DTEST_CLASS=struct
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/subdir/subsubdir/blessed.swift -Xcc -DTEST_PRIVATE=protected
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name main %t/subdir/subsubdir/blessed.swift -Xcc -DTEST_CLASS=struct -Xcc -DTEST_PRIVATE=protected
 //
 // To check that fileID is sensitive to module names, rename cursed.swift to
 // "blessed.swift", but typecheck in a module not called "main".
 //
 // RUN: mv %t/cursed.swift %t/blessed.swift
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name brain %t/blessed.swift
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name brain %t/blessed.swift -Xcc -DTEST_CLASS=struct
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name brain %t/blessed.swift -Xcc -DTEST_PRIVATE=protected
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default -module-name brain %t/blessed.swift -Xcc -DTEST_CLASS=struct -Xcc -DTEST_PRIVATE=protected
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name brain %t/blessed.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name brain %t/blessed.swift -Xcc -DTEST_CLASS=struct
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name brain %t/blessed.swift -Xcc -DTEST_PRIVATE=protected
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=default -module-name brain %t/blessed.swift -Xcc -DTEST_CLASS=struct -Xcc -DTEST_PRIVATE=protected
 
 //--- blessed.swift
 
@@ -120,8 +120,27 @@ extension MyClass {
         let _ = privEnumOpen.variantPrivEnumOpen
     }
 
-    func fcutd(_ _: publTypedef) { }
-    private func fcitd(_ _: privTypedef) { }
+    // Make sure these types are usable in type signatures too
+    func publTypedefFunc(_ _: publTypedef) { }
+    private func privTypedefFunc(_ _: privTypedef) { }
+
+    func publStructFunc(_ _: publStruct) { }
+    private func privStructFunc(_ _: privStruct) { }
+
+    func publEnumFunc(_ _: publEnum) { }
+    private func privEnumFunc(_ _: privEnum) { }
+
+    func publEnumClassFunc(_ _: publEnumClass) { }
+    private func privEnumClassFunc(_ _: privEnumClass) { }
+
+    func publEnumClosedFunc(_ _: publEnumClosed) { }
+    private func privEnumClosedFunc(_ _: privEnumClosed) { }
+
+    func publEnumOpenFunc(_ _: publEnumOpen) { }
+    private func privEnumOpenFunc(_ _: privEnumOpen) { }
+
+    func publEnumFlagFunc(_ _: publEnumFlag) { }
+    private func privEnumFlagFunc(_ _: privEnumFlag) { }
 }
 
 func notExt(_ c: inout MyClass) {
diff --git a/test/Interop/Cxx/class/access/swiftify-private-fileid.swift b/test/Interop/Cxx/class/access/swiftify-private-fileid.swift
new file mode 100644
index 0000000000000..948f935554d1f
--- /dev/null
+++ b/test/Interop/Cxx/class/access/swiftify-private-fileid.swift
@@ -0,0 +1,37 @@
+// REQUIRES: rdar162106643
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-ir -I %swift_src_root/lib/ClangImporter/SwiftBridging -plugin-path %swift-plugin-dir %t/blessed.swift -module-name main -I %t/Inputs -o %t/out -Xcc -std=c++20  -cxx-interoperability-mode=default -enable-experimental-feature SafeInteropWrappers -verify
+
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+//--- Inputs/swiftify-non-public.h
+#pragma once
+
+#include "swift/bridging"
+#include <span>
+
+using IntSpan = std::span<const int>;
+
+class SWIFT_PRIVATE_FILEID("main/blessed.swift") MyClass {
+private:
+    void takesSpan(IntSpan s [[clang::noescape]]) {}
+};
+
+//--- Inputs/module.modulemap
+module SwiftifyNonPublic {
+    requires cplusplus
+    header "swiftify-non-public.h"
+}
+
+//--- blessed.swift
+import CxxStdlib
+import SwiftifyNonPublic
+
+extension MyClass {
+  mutating func passesSpan(_ s: Span<CInt>) {
+    takesSpan(s) // expected-error {{cannot convert value of type}}
+  }
+}
diff --git a/test/Interop/Cxx/class/access/using-non-public-typechecker.swift b/test/Interop/Cxx/class/access/using-non-public-typechecker.swift
index 25cbbae460b3e..cb1c0e8e21d58 100644
--- a/test/Interop/Cxx/class/access/using-non-public-typechecker.swift
+++ b/test/Interop/Cxx/class/access/using-non-public-typechecker.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
 // REQUIRES: swift_feature_ImportNonPublicCxxMembers
 
 import UsingNonPublic
diff --git a/test/Interop/Cxx/class/clang-trivial-abi.swift b/test/Interop/Cxx/class/clang-trivial-abi.swift
index f9415365b4a41..996e4737bd08e 100644
--- a/test/Interop/Cxx/class/clang-trivial-abi.swift
+++ b/test/Interop/Cxx/class/clang-trivial-abi.swift
@@ -2,7 +2,7 @@
 // RUN: split-file %s %t
 
 // RUN: %target-swift-ide-test -print-module -module-to-print=Test -I %t/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
-// RUN: %target-swift-frontend -typecheck -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop -verify
+// RUN: %target-swift-frontend -typecheck -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop -verify -verify-ignore-unrelated
 
 //--- Inputs/module.modulemap
 module Test {
diff --git a/test/Interop/Cxx/class/closure-thunk-executable.swift b/test/Interop/Cxx/class/closure-thunk-executable.swift
index 7c23c2443a12a..82f3ec909b5d6 100644
--- a/test/Interop/Cxx/class/closure-thunk-executable.swift
+++ b/test/Interop/Cxx/class/closure-thunk-executable.swift
@@ -11,4 +11,8 @@ ClosureTestSuite.test("ConvertToFunctionPointer") {
   cfunc2({N in})
 }
 
+ClosureTestSuite.test("Pass FRT to function pointer") {
+  cppGo({N in })
+}
+
 runAllTests()
diff --git a/test/Interop/Cxx/class/closure-thunk-irgen.swift b/test/Interop/Cxx/class/closure-thunk-irgen.swift
index 7745b4364d798..5d8775e68d1af 100644
--- a/test/Interop/Cxx/class/closure-thunk-irgen.swift
+++ b/test/Interop/Cxx/class/closure-thunk-irgen.swift
@@ -5,10 +5,10 @@
 import Closure
 
 // CHECK: define linkonce_odr hidden void @"$sSo10NonTrivialVIegn_ABIeyBX_TR"(ptr %[[V0:.*]], ptr %[[V1:.*]])
-// CHECK: %[[V2:.*]] = getelementptr inbounds { %{{.*}}, %{{.*}} }, ptr %[[V0]], i32 0, i32 1
-// CHECK-NEXT: %[[_FN:.*]] = getelementptr inbounds %{{.*}}, ptr %[[V2]], i32 0, i32 0
+// CHECK: %[[V2:.*]] = getelementptr inbounds{{.*}} { %{{.*}}, %{{.*}} }, ptr %[[V0]], i32 0, i32 1
+// CHECK-NEXT: %[[_FN:.*]] = getelementptr inbounds{{.*}} %{{.*}}, ptr %[[V2]], i32 0, i32 0
 // CHECK-NEXT: %[[V3:.*]] = load ptr, ptr %[[_FN]], align 8
-// CHECK-NEXT: %[[_DATA:.*]] = getelementptr inbounds %{{.*}}, ptr %[[V2]], i32 0, i32 1
+// CHECK-NEXT: %[[_DATA:.*]] = getelementptr inbounds{{.*}} %{{.*}}, ptr %[[V2]], i32 0, i32 1
 // CHECK-NEXT: %[[V4:.*]] = load ptr, ptr %[[_DATA]], align 8
 // CHECK-NEXT: call ptr @swift_retain(ptr returned %[[V4]])
 // CHECK-NEXT: call swiftcc void %[[V3]](ptr noalias dereferenceable(8) %[[V1]], ptr swiftself %[[V4]])
@@ -21,12 +21,7 @@ public func testClosureToBlock() {
 }
 
 // CHECK: define internal void @"$s4main20testClosureToFuncPtryyFySo10NonTrivialVcfU_To"(ptr %[[V0:.*]])
-// CHECK: %[[V1:.*]] = alloca %{{.*}}, align 8
-// CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 8, ptr %[[V1]])
-// CHECK-NEXT: call {{void|ptr}} @_ZN10NonTrivialC1ERKS_(ptr %[[V1]], ptr %[[V0]])
-// CHECK-NEXT: call swiftcc void @"$s4main20testClosureToFuncPtryyFySo10NonTrivialVcfU_"(ptr noalias dereferenceable(8) %[[V1]])
-// CHECK-NEXT: call {{void|ptr}} @_ZN10NonTrivialD1Ev(ptr %[[V1]])
-// CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 8, ptr %[[V1]])
+// CHECK:      call swiftcc void @"$s4main20testClosureToFuncPtryyFySo10NonTrivialVcfU_"(ptr noalias dereferenceable(8) %[[V0]])
 // CHECK-NEXT: ret void
 
 public func testClosureToFuncPtr() {
@@ -41,10 +36,10 @@ public func testClosureToFuncPtrReturnNonTrivial() {
   cfuncReturnNonTrivial2({() -> NonTrivial in return NonTrivial()});
 }
 
-// CHECK: define swiftcc { ptr, ptr } @"$s4main13returnFuncPtrySo10NonTrivialVcyF"()
+// CHECK: define{{( protected)?}} swiftcc { ptr, ptr } @"$s4main13returnFuncPtrySo10NonTrivialVcyF"()
 // CHECK: %[[V0:.*]] = call ptr @_Z8getFnPtrv()
 // CHECK: %[[V1:.*]] = call noalias ptr @swift_allocObject(ptr getelementptr inbounds (%{{.*}}, ptr @{{.*}}, i32 0, i32 2), i64 24, i64 7)
-// CHECK: %[[V2:.*]] = getelementptr inbounds <{ %{{.*}}, ptr }>, ptr %[[V1]], i32 0, i32 1
+// CHECK: %[[V2:.*]] = getelementptr inbounds{{.*}} <{ %{{.*}}, ptr }>, ptr %[[V1]], i32 0, i32 1
 // CHECK: store ptr %[[V0]], ptr %[[V2]], align 8
 // CHECK: %[[V3:.*]] = insertvalue { ptr, ptr } { ptr @"$sSo10NonTrivialVIetCX_ABIegn_TRTA{{(\.ptrauth)?}}", ptr undef }, ptr %[[V1]], 1
 // CHECK: ret { ptr, ptr } %[[V3]]
@@ -52,17 +47,17 @@ public func testClosureToFuncPtrReturnNonTrivial() {
 // CHECK: define linkonce_odr hidden swiftcc void @"$sSo10NonTrivialVIetCX_ABIegn_TR"(ptr noalias dereferenceable(8) %[[V0:.*]], ptr %[[V1:.*]])
 // CHECK: %[[V2:.*]] = alloca %{{.*}}, align 8
 // CHECK: call void @llvm.lifetime.start.p0(i64 8, ptr %[[V2]])
-// CHECK: call {{(void|ptr)}} @_ZN10NonTrivialC1ERKS_(ptr %[[V2]], ptr %[[V0]])
+// CHECK: call {{(void|ptr)}} @_ZN10NonTrivialC{{1|2}}ERKS_(ptr %[[V2]], ptr %[[V0]])
 // CHECK: invoke void %[[V1]](ptr %[[V2]])
 // CHECK: to label %[[INVOKE_CONT:.*]] unwind label %{{.*}}
 
 // CHECK: [[INVOKE_CONT]]:
-// CHECK-NEXT: call {{(void|ptr)}} @_ZN10NonTrivialD1Ev(ptr %[[V2]])
+// CHECK-NEXT: call {{(void|ptr)}} @_ZN10NonTrivialD{{1|2}}Ev(ptr %[[V2]])
 // CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 8, ptr %[[V2]])
 // CHECK-NEXT: ret void
 
 // CHECK: define internal swiftcc void @"$sSo10NonTrivialVIetCX_ABIegn_TRTA"(ptr noalias dereferenceable(8) %[[V0]], ptr swiftself %[[V1]])
-// CHECK: %[[V2]] = getelementptr inbounds <{ %{{.*}}, ptr }>, ptr %[[V1]], i32 0, i32 1
+// CHECK: %[[V2]] = getelementptr inbounds{{.*}} <{ %{{.*}}, ptr }>, ptr %[[V1]], i32 0, i32 1
 // CHECK-NEXT: %[[V3]] = load ptr, ptr %[[V2]], align 8
 // CHECK-NEXT: tail call swiftcc void @"$sSo10NonTrivialVIetCX_ABIegn_TR"(ptr noalias dereferenceable(8) %[[V0]], ptr %[[V3]])
 // CHECK-NEXT: ret void
diff --git a/test/Interop/Cxx/class/closure-thunk-macosx-irgen.swift b/test/Interop/Cxx/class/closure-thunk-macosx-irgen.swift
index 2cc33bdd042d3..9dfe7846df1ee 100644
--- a/test/Interop/Cxx/class/closure-thunk-macosx-irgen.swift
+++ b/test/Interop/Cxx/class/closure-thunk-macosx-irgen.swift
@@ -9,10 +9,10 @@ import Closure
 // CHECK: ret void
 
 // CHECK: define linkonce_odr hidden void @"$sSo10NonTrivialVIegr_ABIeyBr_TR"(ptr noalias sret(%{{.*}}) %[[V0:.*]], ptr %[[V1:.*]])
-// CHECK: %[[V2:.*]] = getelementptr inbounds { %{{.*}}, %{{.*}} }, ptr %[[V1]], i32 0, i32 1
-// CHECK: %[[_FN:.*]] = getelementptr inbounds %{{.*}}, ptr %[[V2]], i32 0, i32 0
+// CHECK: %[[V2:.*]] = getelementptr inbounds{{.*}} { %{{.*}}, %{{.*}} }, ptr %[[V1]], i32 0, i32 1
+// CHECK: %[[_FN:.*]] = getelementptr inbounds{{.*}} %{{.*}}, ptr %[[V2]], i32 0, i32 0
 // CHECK: %[[V3:.*]] = load ptr, ptr %[[_FN]], align 8
-// CHECK: %[[_DATA:.*]] = getelementptr inbounds %{{.*}}, ptr %[[V2]], i32 0, i32 1
+// CHECK: %[[_DATA:.*]] = getelementptr inbounds{{.*}} %{{.*}}, ptr %[[V2]], i32 0, i32 1
 // CHECK: %[[V4:.*]] = load ptr, ptr %[[_DATA]], align 8
 // CHECK: call ptr @swift_retain(ptr returned %[[V4]])
 // CHECK: call swiftcc void %[[V3]](ptr noalias sret(%{{.*}}) %[[V0]], ptr swiftself %[[V4]])
diff --git a/test/Interop/Cxx/class/closure-thunk-macosx.swift b/test/Interop/Cxx/class/closure-thunk-macosx.swift
index 01b459b98aee1..9c84201602da2 100644
--- a/test/Interop/Cxx/class/closure-thunk-macosx.swift
+++ b/test/Interop/Cxx/class/closure-thunk-macosx.swift
@@ -35,3 +35,96 @@ public func testClosureToFuncPtr() {
 public func testClosureToBlockReturnNonTrivial() {
   cfuncReturnNonTrivial({() -> NonTrivial in return NonTrivial() })
 }
+
+// CHECK-LABEL: sil private [thunk] [ossa] @$s4main22testConstRefNonTrivialyyFySo0eF0VcfU_To : $@convention(c) (@in_guaranteed NonTrivial) -> () {
+// CHECK: bb0(%[[V0:.*]] : $*NonTrivial):
+// CHECK: %[[V1:.*]] = alloc_stack $NonTrivial
+// CHECK: copy_addr %[[V0]] to [init] %[[V1]] : $*NonTrivial
+// CHECK: %[[V3:.*]] = function_ref @$s4main22testConstRefNonTrivialyyFySo0eF0VcfU_ : $@convention(thin) (@in_guaranteed NonTrivial) -> ()
+// CHECK: %[[V4:.*]] = apply %[[V3]](%[[V1]]) : $@convention(thin) (@in_guaranteed NonTrivial) -> ()
+// CHECK: destroy_addr %[[V1]] : $*NonTrivial
+// CHECK: dealloc_stack %[[V1]] : $*NonTrivial
+// CHECK: return %[[V4]] : $()
+
+public func testConstRefNonTrivial() {
+  cfuncConstRefNonTrivial({S in });
+}
+
+// CHECK-LABEL: sil private [thunk] [ossa] @$s4main23testConstRefNonTrivial2yyFySo0E7TrivialVcfU_To : $@convention(c) (@in_guaranteed NonTrivial) -> () {
+// CHECK: bb0(%[[V0:.*]] : $*NonTrivial):
+// CHECK: %[[V1:.*]] = alloc_stack $NonTrivial
+// CHECK: copy_addr %[[V0]] to [init] %[[V1]] : $*NonTrivial
+// CHECK: %[[V3:.*]] = function_ref @$s4main23testConstRefNonTrivial2yyFySo0E7TrivialVcfU_ : $@convention(thin) (@in_guaranteed NonTrivial) -> ()
+// CHECK: %[[V4:.*]] = apply %[[V3]](%[[V1]]) : $@convention(thin) (@in_guaranteed NonTrivial) -> ()
+// CHECK: destroy_addr %[[V1]] : $*NonTrivial
+// CHECK: dealloc_stack %[[V1]] : $*NonTrivial
+// CHECK: return %[[V4]] : $()
+public func testConstRefNonTrivial2() {
+  cfuncConstRefNonTrivial(({S in }));
+}
+
+// CHECK-LABEL: sil private [thunk] [ossa] @$s4main19testConstRefTrivialyyFySo0E0VcfU_To : $@convention(c) (@in_guaranteed Trivial) -> () {
+// CHECK: bb0(%[[V0:.*]] : $*Trivial):
+// CHECK: %[[V1:.*]] = function_ref @$s4main19testConstRefTrivialyyFySo0E0VcfU_ : $@convention(thin) (@in_guaranteed Trivial) -> ()
+// CHECK: %[[V2:.*]] = apply %[[V1]](%0) : $@convention(thin) (@in_guaranteed Trivial) -> ()
+// CHECK: return %[[V2]] : $()
+
+public func testConstRefTrivial() {
+  cfuncConstRefTrivial({S in });
+}
+
+// CHECK-LABEL: sil private [thunk] [ossa] @$s4main18testConstRefStrongyyFySo9ARCStrongVcfU_To : $@convention(c) (@in_guaranteed ARCStrong) -> () {
+// CHECK: bb0(%[[V0:.*]] : $*ARCStrong):
+// CHECK: %[[V1:.*]] = alloc_stack $ARCStrong
+// CHECK: copy_addr %[[V0]] to [init] %[[V1]] : $*ARCStrong
+// CHECK: %[[V2:.*]] = function_ref @$s4main18testConstRefStrongyyFySo9ARCStrongVcfU_ : $@convention(thin) (@in_guaranteed ARCStrong) -> ()
+// CHECK: %[[V3:.*]] = apply %[[V2]](%[[V1]]) : $@convention(thin) (@in_guaranteed ARCStrong) -> ()
+// CHECK: destroy_addr %[[V1]] : $*ARCStrong
+// CHECK: dealloc_stack %[[V1]] : $*ARCStrong
+// CHECK: return %[[V3]] : $()
+
+public func testConstRefStrong() {
+  cfuncConstRefStrong({S in });
+}
+
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sSo10NonTrivialVIegn_ABIeyBn_TR : $@convention(c) (@inout_aliasable @block_storage @callee_guaranteed (@in_guaranteed NonTrivial) -> (), @in_guaranteed NonTrivial) -> () {
+// CHECK: bb0(%[[V0:.*]] : $*@block_storage @callee_guaranteed (@in_guaranteed NonTrivial) -> (), %[[V1:.*]] : $*NonTrivial):
+// CHECK: %[[V2:.*]] = project_block_storage %[[V0]] : $*@block_storage @callee_guaranteed (@in_guaranteed NonTrivial) -> ()
+// CHECK: %[[V3:.*]] = load [copy] %[[V2]] : $*@callee_guaranteed (@in_guaranteed NonTrivial) -> ()
+// CHECK: %[[V4:.*]] = begin_borrow %[[V3]] : $@callee_guaranteed (@in_guaranteed NonTrivial) -> ()
+// CHECK: apply %[[V4]](%[[V1]]) : $@callee_guaranteed (@in_guaranteed NonTrivial) -> ()
+// CHECK: end_borrow %[[V4]] : $@callee_guaranteed (@in_guaranteed NonTrivial) -> ()
+// CHECK: destroy_value %[[V3]] : $@callee_guaranteed (@in_guaranteed NonTrivial) -> ()
+
+public func testBlockConstRefNonTrivial() {
+  blockConstRefNonTrivial({S in });
+}
+
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sSo7TrivialVIegy_ABIeyBn_TR : $@convention(c) (@inout_aliasable @block_storage @callee_guaranteed (Trivial) -> (), @in_guaranteed Trivial) -> () {
+// CHECK: bb0(%[[V0:.*]] : $*@block_storage @callee_guaranteed (Trivial) -> (), %[[V1:.*]] : $*Trivial):
+// CHECK: %[[V2:.*]] = project_block_storage %[[V0]] : $*@block_storage @callee_guaranteed (Trivial) -> ()
+// CHECK: %[[V3:.*]] = load [copy] %[[V2]] : $*@callee_guaranteed (Trivial) -> ()
+// CHECK: %[[V4:.*]] = load [trivial] %[[V1]] : $*Trivial
+// CHECK: %[[V5:.*]] = begin_borrow %[[V3]] : $@callee_guaranteed (Trivial) -> ()
+// CHECK: apply %[[V5]](%[[V4]]) : $@callee_guaranteed (Trivial) -> ()
+// CHECK: end_borrow %[[V5]] : $@callee_guaranteed (Trivial) -> ()
+// CHECK: destroy_value %[[V3]] : $@callee_guaranteed (Trivial) -> ()
+
+public func testBlockConstRefTrivial() {
+  blockConstRefTrivial({S in });
+}
+
+// CHECK-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sSo9ARCStrongVIegg_ABIeyBn_TR : $@convention(c) (@inout_aliasable @block_storage @callee_guaranteed (@guaranteed ARCStrong) -> (), @in_guaranteed ARCStrong) -> () {
+// CHECK: bb0(%[[V0:.*]] : $*@block_storage @callee_guaranteed (@guaranteed ARCStrong) -> (), %[[V1:.*]] : $*ARCStrong):
+// CHECK: %[[V2:.*]] = project_block_storage %[[V0]] : $*@block_storage @callee_guaranteed (@guaranteed ARCStrong) -> ()
+// CHECK: %[[V3:.*]] = load [copy] %[[V2]] : $*@callee_guaranteed (@guaranteed ARCStrong) -> ()
+// CHECK: %[[V4:.*]] = load_borrow %[[V1]] : $*ARCStrong
+// CHECK: %[[V5:.*]] = begin_borrow %[[V3]] : $@callee_guaranteed (@guaranteed ARCStrong) -> ()
+// CHECK: apply %[[V5]](%[[V4]]) : $@callee_guaranteed (@guaranteed ARCStrong) -> ()
+// CHECK: end_borrow %[[V5]] : $@callee_guaranteed (@guaranteed ARCStrong) -> ()
+// CHECK: end_borrow %[[V4]] : $ARCStrong
+// CHECK: destroy_value %[[V3]] : $@callee_guaranteed (@guaranteed ARCStrong) -> ()
+
+public func testBlockConstRefStrong() {
+  blockConstRefStrong({S in });
+}
diff --git a/test/Interop/Cxx/class/closure-thunk.swift b/test/Interop/Cxx/class/closure-thunk.swift
index 2c41091387873..463855ddde9ff 100644
--- a/test/Interop/Cxx/class/closure-thunk.swift
+++ b/test/Interop/Cxx/class/closure-thunk.swift
@@ -44,12 +44,8 @@ public func testClosureToBlock() {
 
 // CHECK: sil private [thunk] @$s4main20testClosureToFuncPtryyFySo10NonTrivialVcfU_To : $@convention(c) (@in_cxx NonTrivial) -> () {
 // CHECK: bb0(%[[V0:.*]] : $*NonTrivial):
-// CHECK: %[[V1:.*]] = alloc_stack $NonTrivial
-// CHECK: copy_addr %[[V0]] to [init] %[[V1]] : $*NonTrivial
 // CHECK: %[[V3:.*]] = function_ref @$s4main20testClosureToFuncPtryyFySo10NonTrivialVcfU_ : $@convention(thin) (@in_guaranteed NonTrivial) -> ()
-// CHECK: %[[V4:.*]] = apply %[[V3]](%[[V1]]) : $@convention(thin) (@in_guaranteed NonTrivial) -> ()
-// CHECK: destroy_addr %[[V1]] : $*NonTrivial
-// CHECK: dealloc_stack %[[V1]] : $*NonTrivial
+// CHECK: %[[V4:.*]] = apply %[[V3]](%[[V0]]) : $@convention(thin) (@in_guaranteed NonTrivial) -> ()
 // CHECK: return %[[V4]] : $()
 
 public func testClosureToFuncPtr() {
diff --git a/test/Interop/Cxx/class/conforms-to-associated-types.swift b/test/Interop/Cxx/class/conforms-to-associated-types.swift
new file mode 100644
index 0000000000000..a54b7a5bf1b9b
--- /dev/null
+++ b/test/Interop/Cxx/class/conforms-to-associated-types.swift
@@ -0,0 +1,37 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/include)
+// RUN: split-file %s %t
+//
+// RUN: %target-swift-frontend -typecheck -module-name a -cxx-interoperability-mode=default -I %t/include %t/a.swift
+
+//--- include/module.modulemap
+module cxx {
+  header "header.h"
+  export *
+}
+
+//--- include/header.h
+struct S {
+  S() {}
+} __attribute__((swift_attr("conforms_to:a.P")));
+
+struct S2 {
+  S2() {}
+  using A = S2;
+} __attribute__((swift_attr("conforms_to:a.P")));
+
+//--- a.swift
+import cxx
+public protocol P {
+  associatedtype A = Int
+  func foo(_: A)
+}
+extension P {
+  func foo(_: A) {}
+}
+func test(s: S) {
+  let _ = s.foo(0)
+}
+func test2(s: S2) {
+  let _ = s.foo(s)
+}
diff --git a/test/Interop/Cxx/class/conforms-to-errors.swift b/test/Interop/Cxx/class/conforms-to-errors.swift
index 4a6373f3b398a..65b2e5f5a7aaf 100644
--- a/test/Interop/Cxx/class/conforms-to-errors.swift
+++ b/test/Interop/Cxx/class/conforms-to-errors.swift
@@ -16,6 +16,65 @@ struct  __attribute__((swift_attr("conforms_to:SwiftTest.X"))) CX {};
 struct  __attribute__((swift_attr("conforms_to:SwiftTest.A"))) CA {};
 struct  __attribute__((swift_attr("conforms_to:SwiftTest.B"))) CB {};
 
+struct  __attribute__((swift_attr("conforms_to:X")))
+    __attribute__((swift_attr("conforms_to:X"))) CXX {};
+struct  __attribute__((swift_attr("conforms_to:X")))
+    __attribute__((swift_attr("conforms_to:Mod.X"))) CXModX {};
+struct  __attribute__((swift_attr("conforms_to:X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.X"))) CXTextX {};
+struct  __attribute__((swift_attr("conforms_to:X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.A"))) CXA {};
+struct  __attribute__((swift_attr("conforms_to:X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.B"))) CXB {};
+struct  __attribute__((swift_attr("conforms_to:X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.C"))) CXC {};
+
+
+struct  __attribute__((swift_attr("conforms_to:Mod.X")))
+    __attribute__((swift_attr("conforms_to:Mod.X"))) CModXModX {};
+struct  __attribute__((swift_attr("conforms_to:Mod.X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.X"))) CModXTestX {};
+struct  __attribute__((swift_attr("conforms_to:Mod.X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.A"))) CModXA {};
+struct  __attribute__((swift_attr("conforms_to:Mod.X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.B"))) CModXB {};
+struct  __attribute__((swift_attr("conforms_to:Mod.X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.C"))) CModXC {};
+
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.X"))) CTestXTextX {};
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.A"))) CTextXA {};
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.B"))) CTextXB {};
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.X")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.C"))) CTextXC {};
+
+
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.A")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.A"))) CAA {};
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.A")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.B"))) CAB {};
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.A")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.C"))) CAC {};
+
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.B")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.B"))) CBB {};
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.B")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.C"))) CBC {};
+
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.C")))
+    __attribute__((swift_attr("conforms_to:SwiftTest.C"))) CCC {};
+
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.D"))) CD {};
+struct  __attribute__((swift_attr("conforms_to:SwiftTest.D"))) CDD: CD {};
+
+struct __attribute__((swift_attr("conforms_to:SwiftTest.D"))) CD2 {};
+struct CCDCD2 : CD, CD2 {};
+
+struct __attribute__((swift_attr("conforms_to:SwiftTest.D"))) 
+    __attribute__((swift_attr("conforms_to:SwiftTest.E"))) CDE {};
+
 //--- test.swift
 
 import Test
@@ -25,10 +84,78 @@ struct B {}
 protocol A {}
 protocol A {}
 
+protocol C {}
+protocol D {}
+protocol E: D {}
+
 // CHECK: error: expected module name and protocol name separated by '.' in protocol conformance; 'X' is invalid
 // CHECK: module 'Mod' in specified protocol conformance 'Mod.X' is not found; did you mean to import it first?
 // CHECK: error: protocol 'X' in specified protocol conformance is not found in module 'SwiftTest'
 // CHECK: error: ambiguous reference to protocol 'A' in specified protocol conformance; module 'SwiftTest' contains multiple protocols named 'A'
 // CHECK: error: struct 'B' referenced in protocol conformance 'SwiftTest.B' is not a protocol
-
 func test(_ inv: CInv, _ invMod: CModInv, _ x: CX, _ a: CA, _ b: CB) {}
+
+// CHECK: error: expected module name and protocol name separated by '.' in protocol conformance; 'X' is invalid
+// CHECK: error: expected module name and protocol name separated by '.' in protocol conformance; 'X' is invalid
+
+// CHECK: error: expected module name and protocol name separated by '.' in protocol conformance; 'X' is invalid
+// CHECK: module 'Mod' in specified protocol conformance 'Mod.X' is not found; did you mean to import it first?
+
+// CHECK: error: expected module name and protocol name separated by '.' in protocol conformance; 'X' is invalid
+// CHECK: error: protocol 'X' in specified protocol conformance is not found in module 'SwiftTest'
+
+// CHECK: error: expected module name and protocol name separated by '.' in protocol conformance; 'X' is invalid
+// CHECK: error: ambiguous reference to protocol 'A' in specified protocol conformance; module 'SwiftTest' contains multiple protocols named 'A'
+
+// CHECK: error: expected module name and protocol name separated by '.' in protocol conformance; 'X' is invalid
+// CHECK: error: struct 'B' referenced in protocol conformance 'SwiftTest.B' is not a protocol
+
+// CHECK: error: expected module name and protocol name separated by '.' in protocol conformance; 'X' is invalid
+func test(_ xx: CXX, _ xModx: CXModX, _ xTextX: CXTextX, _ cxa: CXA, _ cxb: CXB, _ cxc: CXC) {}
+
+// CHECK: module 'Mod' in specified protocol conformance 'Mod.X' is not found; did you mean to import it first?
+// CHECK: module 'Mod' in specified protocol conformance 'Mod.X' is not found; did you mean to import it first?
+
+// CHECK: module 'Mod' in specified protocol conformance 'Mod.X' is not found; did you mean to import it first?
+// CHECK: error: protocol 'X' in specified protocol conformance is not found in module 'SwiftTest'
+
+// CHECK: module 'Mod' in specified protocol conformance 'Mod.X' is not found; did you mean to import it first?
+// CHECK: error: ambiguous reference to protocol 'A' in specified protocol conformance; module 'SwiftTest' contains multiple protocols named 'A'
+
+// CHECK: module 'Mod' in specified protocol conformance 'Mod.X' is not found; did you mean to import it first?
+// CHECK: error: struct 'B' referenced in protocol conformance 'SwiftTest.B' is not a protocol
+
+// CHECK: module 'Mod' in specified protocol conformance 'Mod.X' is not found; did you mean to import it first?
+func test(_ modXModX: CModXModX, _ modXTestX: CModXTestX, _ modXA: CModXA, _ modXB: CModXB, _ modXC: CModXC) {}
+
+// CHECK: error: protocol 'X' in specified protocol conformance is not found in module 'SwiftTest'
+// CHECK: error: protocol 'X' in specified protocol conformance is not found in module 'SwiftTest'
+
+// CHECK: error: protocol 'X' in specified protocol conformance is not found in module 'SwiftTest'
+// CHECK: error: ambiguous reference to protocol 'A' in specified protocol conformance; module 'SwiftTest' contains multiple protocols named 'A'
+
+// CHECK: error: protocol 'X' in specified protocol conformance is not found in module 'SwiftTest'
+// CHECK: error: struct 'B' referenced in protocol conformance 'SwiftTest.B' is not a protocol
+
+// CHECK: error: protocol 'X' in specified protocol conformance is not found in module 'SwiftTest'
+func test(_ testXTextX: CTestXTextX, _ textXA: CTextXA, _ textXB: CTextXB, _ textXC: CTextXC) {}
+
+// CHECK: error: ambiguous reference to protocol 'A' in specified protocol conformance; module 'SwiftTest' contains multiple protocols named 'A'
+// CHECK: error: ambiguous reference to protocol 'A' in specified protocol conformance; module 'SwiftTest' contains multiple protocols named 'A'
+
+// CHECK: error: ambiguous reference to protocol 'A' in specified protocol conformance; module 'SwiftTest' contains multiple protocols named 'A'
+// CHECK: error: struct 'B' referenced in protocol conformance 'SwiftTest.B' is not a protocol
+
+// CHECK: error: ambiguous reference to protocol 'A' in specified protocol conformance; module 'SwiftTest' contains multiple protocols named 'A'
+func test(_ aa: CAA, _ ab: CAB, _ ac: CAC) {}
+
+// CHECK: error: struct 'B' referenced in protocol conformance 'SwiftTest.B' is not a protocol
+func test(_ bb: CBB, _ bc: CBC) {}
+
+// CHECK: error: redundant conformance of 'CCC' to protocol 'SwiftTest.C'
+func test(_ cc: CCC) {}
+
+// CHECK-NOT: error: redundant conformance of 'CDD' to protocol 'SwiftTest.D'
+// CHECK-NOT: error: redundant conformance of 'CCDCD2' to protocol 'SwiftTest.D'
+// CHECK-NOT: error: redundant conformance of 'CDE' to protocol 'SwiftTest.D'
+func test(_ dd: CDD, _ dd2: CCDCD2, de: CDE) {}
\ No newline at end of file
diff --git a/test/Interop/Cxx/class/conforms-to-missing-associated-type.swift b/test/Interop/Cxx/class/conforms-to-missing-associated-type.swift
new file mode 100644
index 0000000000000..e62f49d991dc3
--- /dev/null
+++ b/test/Interop/Cxx/class/conforms-to-missing-associated-type.swift
@@ -0,0 +1,31 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/include)
+// RUN: split-file %s %t
+//
+// RUN: %target-swift-frontend -typecheck -module-name a -cxx-interoperability-mode=default -I %t/include %t/a.swift -verify
+
+//--- include/module.modulemap
+module cxx {
+  header "header.h"
+  export *
+}
+
+//--- include/header.h
+struct S {
+  S() {}
+} __attribute__((swift_attr("conforms_to:a.P")));
+
+//--- a.swift
+import cxx
+// expected-error@+2{{type 'S' does not conform to protocol 'P'}}
+// expected-note@+1{{protocol requires nested type 'A'}}
+public protocol P {
+  associatedtype A
+  func foo(_: A)
+}
+extension P {
+  func foo(_: A) {}
+}
+func test(x : S) {
+    x.foo(0) // expected-error{{cannot convert value of type 'Int' to expected argument type 'S.A'}}
+}
diff --git a/test/Interop/Cxx/class/conforms-to.swift b/test/Interop/Cxx/class/conforms-to.swift
index a54d9e37ccf44..ea3133d2c2efe 100644
--- a/test/Interop/Cxx/class/conforms-to.swift
+++ b/test/Interop/Cxx/class/conforms-to.swift
@@ -35,13 +35,24 @@ func callee(_ _: Playable) {
 func caller(_ x: Playable) {
     callee(x)
 }
+
+func caller(_ x: MultipleConformanceHasTestAndPlay) {
+    callee(x as Testable)
+    callee(x as Playable)
+}
+
 func caller(_ x: DerivedFromHasPlay) { callee(x) }
 func caller(_ x: DerivedFromDerivedFromHasPlay) { callee(x) }
+func caller(_ x: DerivedFromMultipleConformanceHasTestAndPlay) {
+    callee(x as Testable)
+    callee(x as Playable)
+}
 
 func caller(_ x: HasTestAndPlay) {
     callee(x as Testable)
     callee(x as Playable)
 }
+
 func caller(_ x: DerivedFromHasTestAndPlay) {
     callee(x as Testable)
     callee(x as Playable)
diff --git a/test/Interop/Cxx/class/constructor-inherited-from-base-irgen.swift b/test/Interop/Cxx/class/constructor-inherited-from-base-irgen.cpp
similarity index 100%
rename from test/Interop/Cxx/class/constructor-inherited-from-base-irgen.swift
rename to test/Interop/Cxx/class/constructor-inherited-from-base-irgen.cpp
diff --git a/test/Interop/Cxx/class/constructors-copy-module-interface.swift b/test/Interop/Cxx/class/constructors-copy-module-interface.swift
index 042c10e7d1d9b..254f6543b58af 100644
--- a/test/Interop/Cxx/class/constructors-copy-module-interface.swift
+++ b/test/Interop/Cxx/class/constructors-copy-module-interface.swift
@@ -1,4 +1,5 @@
 // RUN: %target-swift-ide-test -print-module -module-to-print=Constructors -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
+// XFAIL: OS=linux-androideabi
 
 // CHECK: struct TemplatedCopyConstructor
 // CHECK: struct TemplatedCopyConstructorWithExtraArg
diff --git a/test/Interop/Cxx/class/constructors-diagnostics.swift b/test/Interop/Cxx/class/constructors-diagnostics.swift
index 139142d6ee91f..8fa99fae7fb12 100644
--- a/test/Interop/Cxx/class/constructors-diagnostics.swift
+++ b/test/Interop/Cxx/class/constructors-diagnostics.swift
@@ -1,8 +1,8 @@
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs  %s -cxx-interoperability-mode=default -enable-experimental-feature CXXForeignReferenceTypeInitializers -disable-availability-checking -verify-additional-file %S/Inputs/constructors.h -Xcc -Wno-nullability-completeness
+// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs  %s -cxx-interoperability-mode=default -disable-availability-checking -verify-additional-file %S/Inputs/constructors.h -Xcc -Wno-nullability-completeness
 
-// This test uses -verify-additional-file, which do not work well on Windows:
+// This test uses -verify-additional-file, which do not work well on Windows.
 // UNSUPPORTED: OS=windows-msvc
-// REQUIRES: swift_feature_CXXForeignReferenceTypeInitializers
+// XFAIL: OS=linux-androideabi
 
 import Constructors
 
@@ -17,11 +17,12 @@ let _ = SwiftInitSynthesisForCXXRefTypes.ProtectedCtor()  // expected-error {{'S
 let _ = SwiftInitSynthesisForCXXRefTypes.DeletedCtor()  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.DeletedCtor' cannot be constructed because it has no accessible initializers}}
 
 let _ = SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultArg()  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultArg' cannot be constructed because it has no accessible initializers}}
+let _ = SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultArg(1)  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultArg' cannot be constructed because it has no accessible initializers}}
+let _ = SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultArg(1, 2)  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultArg' cannot be constructed because it has no accessible initializers}}
 let _ = SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultAndNonDefaultArg()  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultAndNonDefaultArg' cannot be constructed because it has no accessible initializers}}
+let _ = SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultAndNonDefaultArg(1)  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultAndNonDefaultArg' cannot be constructed because it has no accessible initializers}}
+let _ = SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultAndNonDefaultArg(1, 2)  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultAndNonDefaultArg' cannot be constructed because it has no accessible initializers}}
+let _ = SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultAndNonDefaultArg(1, 2, 3)  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultAndNonDefaultArg' cannot be constructed because it has no accessible initializers}}
 
-let _ = SwiftInitSynthesisForCXXRefTypes.DefaulltAndNonDefaultCtors()
-// TODO: change the error message when we start supporting parameterised ctors
-let _ = SwiftInitSynthesisForCXXRefTypes.DefaulltAndNonDefaultCtors(2)  // expected-error {{argument passed to call that takes no arguments}}
-
-let _ = SwiftInitSynthesisForCXXRefTypes.ParameterizedCtor()  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.ParameterizedCtor' cannot be constructed because it has no accessible initializers}}
-let _ = SwiftInitSynthesisForCXXRefTypes.ParameterizedCtor(3)  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.ParameterizedCtor' cannot be constructed because it has no accessible initializers}}
+let _ = SwiftInitSynthesisForCXXRefTypes.VariadicCtors()  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.VariadicCtors' cannot be constructed because it has no accessible initializers}}
+let _ = SwiftInitSynthesisForCXXRefTypes.VariadicCtors(1)  // expected-error {{'SwiftInitSynthesisForCXXRefTypes.VariadicCtors' cannot be constructed because it has no accessible initializers}}
diff --git a/test/Interop/Cxx/class/constructors-executable.swift b/test/Interop/Cxx/class/constructors-executable.swift
index dc85576bf0cb8..d28898159cb9b 100644
--- a/test/Interop/Cxx/class/constructors-executable.swift
+++ b/test/Interop/Cxx/class/constructors-executable.swift
@@ -1,9 +1,9 @@
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -cxx-interoperability-mode=default -enable-experimental-feature CXXForeignReferenceTypeInitializers -Xfrontend -disable-availability-checking)
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -cxx-interoperability-mode=default -Xfrontend -disable-availability-checking)
 //
 // REQUIRES: executable_test
-// REQUIRES: swift_feature_CXXForeignReferenceTypeInitializers
 
 import Constructors
+import CxxStdlib
 import StdlibUnittest
 
 var CxxConstructorTestSuite = TestSuite("CxxConstructors")
@@ -113,6 +113,74 @@ CxxConstructorTestSuite.test("SynthesizeAndImportStaticFactoryAsInitializer") {
 
   let x6 = SwiftInitSynthesisForCXXRefTypes.UserProvidedStaticFactory(3)
   expectEqual(x6.val, 3)
+
+  let x7 = SwiftInitSynthesisForCXXRefTypes.ParameterizedCtor(2)
+  expectEqual(x7.val, 2)
+  x7.val = 3
+  expectEqual(x7.val, 3)
+
+  let x8 = SwiftInitSynthesisForCXXRefTypes.ParameterizedCtor2()
+  expectEqual(x8.val1, 1)
+  expectEqual(x8.val2, 1)
+  x8.val1 = 2
+  expectEqual(x8.val1, 2)
+  expectEqual(x8.val2, 1)
+
+  let y8 = SwiftInitSynthesisForCXXRefTypes.ParameterizedCtor2(2)
+  expectEqual(y8.val1, 2)
+  expectEqual(y8.val2, 1)
+  y8.val1 = 3
+  expectEqual(y8.val1, 3)
+  expectEqual(y8.val2, 1)
+
+  let z8 = SwiftInitSynthesisForCXXRefTypes.ParameterizedCtor2(2, 3)
+  expectEqual(z8.val1, 2)
+  expectEqual(z8.val2, 3)
+  z8.val1 = 4
+  z8.val2 = 5
+  expectEqual(z8.val1, 4)
+  expectEqual(z8.val2, 5)
+
+  let x9 = SwiftInitSynthesisForCXXRefTypes.DefaulltAndNonDefaultCtors()
+  expectEqual(x9.val, 1)
+  x9.val = 2
+  expectEqual(x9.val, 2)
+  let y9 = SwiftInitSynthesisForCXXRefTypes.DefaulltAndNonDefaultCtors(3)
+  expectEqual(y9.val, 3)
+  y9.val = 4
+  expectEqual(y9.val, 4)
+
+  let x10 = SwiftInitSynthesisForCXXRefTypes.NoIdentifierInCtorParam(10)
+  expectEqual(x10.val, 10)
+
+  let x12 = SwiftInitSynthesisForCXXRefTypes.cxxValTy(5)
+  let y12 = SwiftInitSynthesisForCXXRefTypes.RValRefCtor2(consuming: x12)
+  expectEqual(y12.val.val, 5)
+
+  let x13 = SwiftInitSynthesisForCXXRefTypes.UserDefinedCopyCtor(2)
+  let x14 = x13
+  expectEqual(x13.val, 2)
+  expectEqual(x14.val, 2)
+  x13.val = 3
+  expectEqual(x13.val, 3)
+  expectEqual(x14.val, 3)
+}
+
+CxxConstructorTestSuite.test("SynthesizedStaticFactoriesDoNotEmitDiagnosticsWithoutInitCall") {
+  let _: SwiftInitSynthesisForCXXRefTypes.PrivateOperatorNew
+
+  let _: SwiftInitSynthesisForCXXRefTypes.PrivateOperatorNew
+  let _: SwiftInitSynthesisForCXXRefTypes.ProtectedOperatorNew
+  let _: SwiftInitSynthesisForCXXRefTypes.DeletedOperatorNew
+
+  let _: SwiftInitSynthesisForCXXRefTypes.PrivateCtor
+  let _: SwiftInitSynthesisForCXXRefTypes.ProtectedCtor
+  let _: SwiftInitSynthesisForCXXRefTypes.DeletedCtor
+
+  let _: SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultArg
+  let _: SwiftInitSynthesisForCXXRefTypes.CtorWithDefaultAndNonDefaultArg
+
+  let _: SwiftInitSynthesisForCXXRefTypes.VariadicCtors
 }
 
 runAllTests()
diff --git a/test/Interop/Cxx/class/constructors-module-interface.swift b/test/Interop/Cxx/class/constructors-module-interface.swift
index bf189b6e3024b..d2c3d65f03e68 100644
--- a/test/Interop/Cxx/class/constructors-module-interface.swift
+++ b/test/Interop/Cxx/class/constructors-module-interface.swift
@@ -1,4 +1,5 @@
 // RUN: %target-swift-ide-test -print-module -module-to-print=Constructors -I %S/Inputs/ -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
+// XFAIL: OS=linux-androideabi
 
 // CHECK:      struct ExplicitDefaultConstructor {
 // CHECK-NEXT:   init()
diff --git a/test/Interop/Cxx/class/constructors-silgen.swift b/test/Interop/Cxx/class/constructors-silgen.swift
index b1624ccccfe52..79cbdf170de9c 100644
--- a/test/Interop/Cxx/class/constructors-silgen.swift
+++ b/test/Interop/Cxx/class/constructors-silgen.swift
@@ -1,4 +1,5 @@
 // RUN: %target-swiftxx-frontend -I %S/Inputs -Xllvm -sil-print-types -emit-silgen %s | %FileCheck %s
+// XFAIL: OS=linux-androideabi
 
 import Constructors
 
diff --git a/test/Interop/Cxx/class/constructors-typechecker.swift b/test/Interop/Cxx/class/constructors-typechecker.swift
index 8ce10b1ca752a..c5680d4a5125c 100644
--- a/test/Interop/Cxx/class/constructors-typechecker.swift
+++ b/test/Interop/Cxx/class/constructors-typechecker.swift
@@ -1,4 +1,5 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -enable-experimental-cxx-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -enable-experimental-cxx-interop
+// XFAIL: OS=linux-androideabi
 
 import Constructors
 
diff --git a/test/Interop/Cxx/class/custom-new-operator-irgen.swift b/test/Interop/Cxx/class/custom-new-operator-irgen.swift
index 74e692c9db20a..0423493afac1a 100644
--- a/test/Interop/Cxx/class/custom-new-operator-irgen.swift
+++ b/test/Interop/Cxx/class/custom-new-operator-irgen.swift
@@ -5,4 +5,4 @@ import CustomNewOperator
 var x = callsCustomNew()
 
 // Make sure the definition of `operator new` is emitted.
-// CHECK: define {{.*}} @{{_ZnwmPv15container_new_t|"\?\?2@YAPEAX_KPEAXUcontainer_new_t@@@Z"}}
+// CHECK: define {{.*}} @{{_Znw(j|m)Pv15container_new_t|"\?\?2@YAPEAX_KPEAXUcontainer_new_t@@@Z"}}
diff --git a/test/Interop/Cxx/class/for-each-field.swift b/test/Interop/Cxx/class/for-each-field.swift
new file mode 100644
index 0000000000000..fbe885b76d8d2
--- /dev/null
+++ b/test/Interop/Cxx/class/for-each-field.swift
@@ -0,0 +1,77 @@
+// RUN: %target-run-simple-swift(-cxx-interoperability-mode=default -Xfrontend -disable-availability-checking -I %S/Inputs)
+
+// REQUIRES: executable_test
+// REQUIRES: reflection
+// UNSUPPORTED: back_deployment_runtime || use_os_stdlib
+
+@_spi(Reflection) import Swift
+import SimpleStructs
+import StdlibUnittest
+
+func checkFieldsWithKeyPath<T>(
+  of type: T.Type,
+  options: _EachFieldOptions = [],
+  fields: [String: PartialKeyPath<T>]
+) {
+  var count = 0
+
+  _forEachFieldWithKeyPath(of: T.self, options: options) {
+    charPtr, keyPath in
+    count += 1
+
+    let fieldName = String(cString: charPtr)
+    if fieldName == "" {
+      expectTrue(false, "Empty field name")
+      return true
+    }
+    guard let checkKeyPath = fields[fieldName] else {
+      expectTrue(false, "Unexpected field '\(fieldName)'")
+      return true
+    }
+
+    expectTrue(checkKeyPath == keyPath)
+    return true
+  }
+
+  expectEqual(fields.count, count)
+}
+
+var ForEachFieldTestSuite = TestSuite("ForEachField")
+
+ForEachFieldTestSuite.test("HasPrivateFieldsOnly") {
+  checkFieldsWithKeyPath(
+    of: HasPrivateFieldsOnly.self,
+    fields: [:]
+  )
+}
+
+ForEachFieldTestSuite.test("HasPublicFieldsOnly") {
+  checkFieldsWithKeyPath(
+    of: HasPublicFieldsOnly.self,
+    fields: [
+      "publ1": \HasPublicFieldsOnly.publ1,
+      "publ2": \HasPublicFieldsOnly.publ2
+    ]
+  )
+}
+
+ForEachFieldTestSuite.test("HasPrivatePublicProtectedFields") {
+  checkFieldsWithKeyPath(
+    of: HasPrivatePublicProtectedFields.self,
+    fields: [
+      "publ1": \HasPrivatePublicProtectedFields.publ1,
+      "publ2": \HasPrivatePublicProtectedFields.publ2
+    ]
+  )
+}
+
+ForEachFieldTestSuite.test("Outer") {
+  checkFieldsWithKeyPath(
+    of: Outer.self,
+    fields: [
+      "publStruct": \Outer.publStruct
+    ]
+  )
+}
+
+runAllTests()
diff --git a/test/Interop/Cxx/class/friend-diag.swift b/test/Interop/Cxx/class/friend-diag.swift
index a34f353827038..b5f26bccd1349 100644
--- a/test/Interop/Cxx/class/friend-diag.swift
+++ b/test/Interop/Cxx/class/friend-diag.swift
@@ -1,6 +1,6 @@
 // RUN: rm -rf %t
 // RUN: split-file %s %t
-// RUN: %target-swiftxx-frontend -typecheck -I %t/Inputs %t/test.swift -verify
+// RUN: %target-swiftxx-frontend -typecheck -I %t/Inputs %t/test.swift -verify -verify-ignore-unrelated
 
 //--- Inputs/module.modulemap
 module FriendClass {
diff --git a/test/Interop/Cxx/class/function-call-irgen.swift b/test/Interop/Cxx/class/function-call-irgen.swift
index c2d45e7ddf39a..acba58ed69b98 100644
--- a/test/Interop/Cxx/class/function-call-irgen.swift
+++ b/test/Interop/Cxx/class/function-call-irgen.swift
@@ -4,12 +4,12 @@
 
 import Closure
 
-// CHECK: define swiftcc void @"$s4main14testNonTrivialyyF"()
+// CHECK: define{{( protected)?}} swiftcc void @"$s4main14testNonTrivialyyF"()
 // CHECK: %[[V0:.*]] = alloca %{{.*}}, align 8
 // CHECK: call void @llvm.lifetime.start.p0(i64 8, ptr %[[V0]])
 // CHECK: call {{(void|ptr)}} @__swift_cxx_ctor_ZN10NonTrivialC1Ev(ptr %[[V0]])
 // CHECK: call void @_Z5cfunc10NonTrivial(ptr %[[V0]])
-// CHECK: call {{(void|ptr)}} @_ZN10NonTrivialD1Ev(ptr %[[V0]])
+// CHECK: call {{(void|ptr)}} @_ZN10NonTrivialD{{1|2}}Ev(ptr %[[V0]])
 // CHECK: call void @llvm.lifetime.end.p0(i64 8, ptr %[[V0]])
 // CHECK: ret void
 
@@ -17,7 +17,7 @@ public func testNonTrivial() {
   cfunc(NonTrivial());
 }
 
-// CHECK: define swiftcc void @"$s4main29testNonTrivialFunctionPointeryyF"()
+// CHECK: define{{( protected)?}} swiftcc void @"$s4main29testNonTrivialFunctionPointeryyF"()
 // CHECK: %[[F_DEBUG:.*]] = alloca ptr, align 8
 // CHECK: call void @llvm.memset.p0.i64(ptr align 8 %[[F_DEBUG]], i8 0, i64 8, i1 false)
 // CHECK: %[[V0:.*]] = alloca %{{.*}}, align 8
@@ -29,7 +29,7 @@ public func testNonTrivial() {
 // CHECK: to label %[[INVOKE_CONT:.*]] unwind label %{{.*}}
 
 // CHECK: [[INVOKE_CONT]]:
-// CHECK: call {{(void|ptr)}} @_ZN10NonTrivialD1Ev(ptr %[[V0]])
+// CHECK: call {{(void|ptr)}} @_ZN10NonTrivialD{{1|2}}Ev(ptr %[[V0]])
 // CHECK: call void @llvm.lifetime.end.p0(i64 8, ptr %[[V0]])
 // CHECK: ret void
 
diff --git a/test/Interop/Cxx/class/inheritance/Inputs/circular-inheritance.h b/test/Interop/Cxx/class/inheritance/Inputs/circular-inheritance.h
new file mode 100644
index 0000000000000..cbd96e4ca2b41
--- /dev/null
+++ b/test/Interop/Cxx/class/inheritance/Inputs/circular-inheritance.h
@@ -0,0 +1,32 @@
+#ifndef CIRCULAR_INHERITANCE_H
+#define CIRCULAR_INHERITANCE_H
+
+struct DinoEgg {
+  void dinoEgg(void) const {}
+};
+
+template <typename Chicken>
+struct Egg;
+
+template <>
+struct Egg<void> : DinoEgg {
+  Egg() {}
+  void voidEgg(void) const {}
+};
+
+template <typename Chicken>
+struct Egg : Egg<void> {
+  Egg(Chicken _chicken) {}
+  Chicken chickenEgg(Chicken c) const { return c; }
+};
+
+typedef Egg<void> VoidEgg;
+typedef Egg<bool> BoolEgg;
+typedef Egg<Egg<void>> EggEgg;
+
+struct NewEgg : Egg<int> {
+  NewEgg() : Egg<int>(555) {}
+  void newEgg() const {}
+};
+
+#endif // !CIRCULAR_INHERITANCE_H
diff --git a/test/Interop/Cxx/class/inheritance/Inputs/inherited-lookup.h b/test/Interop/Cxx/class/inheritance/Inputs/inherited-lookup.h
index c2bf7ff4fe9f3..b67cbbc1f85e5 100644
--- a/test/Interop/Cxx/class/inheritance/Inputs/inherited-lookup.h
+++ b/test/Interop/Cxx/class/inheritance/Inputs/inherited-lookup.h
@@ -16,3 +16,12 @@ struct IIOne : IOne {
 struct IIIOne : IIOne {
   int methodIII(void) const { return -111; }
 };
+
+class Base {
+public:
+  bool baseMethod() const { return true; }
+};
+
+namespace Bar {
+class Derived : public Base {};
+} // namespace Bar
diff --git a/test/Interop/Cxx/class/inheritance/Inputs/module.modulemap b/test/Interop/Cxx/class/inheritance/Inputs/module.modulemap
index 45736330ddf5e..007e8f550b970 100644
--- a/test/Interop/Cxx/class/inheritance/Inputs/module.modulemap
+++ b/test/Interop/Cxx/class/inheritance/Inputs/module.modulemap
@@ -16,8 +16,8 @@ module ReferenceToDerived {
   requires cplusplus
 }
 
-module SubTypes {
-  header "sub-types.h"
+module NestedTypes {
+  header "nested-types.h"
 }
 
 module Subscripts {
@@ -48,3 +48,8 @@ module InheritedLookup {
   header "inherited-lookup.h"
   requires cplusplus
 }
+
+module CircularInheritance {
+  header "circular-inheritance.h"
+  requires cplusplus
+}
diff --git a/test/Interop/Cxx/class/inheritance/Inputs/nested-types.h b/test/Interop/Cxx/class/inheritance/Inputs/nested-types.h
new file mode 100644
index 0000000000000..866c21925a909
--- /dev/null
+++ b/test/Interop/Cxx/class/inheritance/Inputs/nested-types.h
@@ -0,0 +1,24 @@
+struct Base {
+  enum class EnumClass : char { eca = 2, ecb = 3, ecc = 4 };
+  enum Enum { ea, eb, ec };
+
+  struct Struct {
+    int sa;
+    int sb;
+  };
+
+  struct Parent {
+    struct Child {
+      int pca;
+    };
+  };
+
+  union Union {
+    int ua;
+    Struct ub;
+  };
+};
+
+struct Derived : Base {};
+struct Derived1 : Base {};
+struct Derived2 : Derived1 {};
diff --git a/test/Interop/Cxx/class/inheritance/Inputs/sub-types.h b/test/Interop/Cxx/class/inheritance/Inputs/sub-types.h
deleted file mode 100644
index b5f013fe2eb32..0000000000000
--- a/test/Interop/Cxx/class/inheritance/Inputs/sub-types.h
+++ /dev/null
@@ -1,22 +0,0 @@
-struct Base {
-  enum class EnumClass : char { eca = 2, ecb = 3, ecc = 4 };
-  enum Enum { ea, eb, ec };
-
-  struct Struct {
-    int sa;
-    int sb;
-  };
-
-  struct Parent {
-    struct Child {
-      int pca;
-    };
-  };
-
-  union Union {
-    int ua;
-    Struct ub;
-  };
-};
-
-struct Derived : Base {};
diff --git a/test/Interop/Cxx/class/inheritance/Inputs/virtual-methods.h b/test/Interop/Cxx/class/inheritance/Inputs/virtual-methods.h
index df56331001de6..b9029c23a37e2 100644
--- a/test/Interop/Cxx/class/inheritance/Inputs/virtual-methods.h
+++ b/test/Interop/Cxx/class/inheritance/Inputs/virtual-methods.h
@@ -6,6 +6,8 @@ inline void testFunctionCollected() {
 
 struct Base {
   virtual void foo() = 0;
+  virtual void virtualRename() const
+      __attribute__((swift_name("swiftVirtualRename()")));
 };
 
 struct Base2 { virtual int f() = 0; };
@@ -49,48 +51,3 @@ struct DerivedFromCallsPureMethod : CallsPureMethod {
 };
 
 struct DerivedFromDerivedFromCallsPureMethod : DerivedFromCallsPureMethod {};
-
-struct HasDestructor {
-  ~HasDestructor() {}
-};
-
-// MARK: Reference Types:
-
-#define IMMORTAL_FRT                                                           \
-  __attribute__((swift_attr("import_reference")))                              \
-  __attribute__((swift_attr("retain:immortal")))                               \
-  __attribute__((swift_attr("release:immortal")))
-
-struct IMMORTAL_FRT ImmortalBase {
-  int value = 0;
-
-  virtual int get42() const { return 42; }
-  virtual int getOverridden42() const { return 123; }
-  virtual int getIntValue() const { return value; }
-};
-
-struct IMMORTAL_FRT Immortal : public ImmortalBase {
-  static Immortal *_Nonnull create() { return new Immortal(); }
-
-  virtual int getOverridden42() const override { return 42; }
-  virtual void setIntValue(int newValue) { this->value = newValue; }
-};
-
-struct IMMORTAL_FRT DerivedFromImmortal : public Immortal {
-  static DerivedFromImmortal *_Nonnull create() { return new DerivedFromImmortal(); }
-};
-
-struct IMMORTAL_FRT Immortal2 {
-public:
-  virtual void virtualMethod(HasDestructor) = 0;
-};
-
-inline const ImmortalBase *_Nonnull castToImmortalBase(
-    const Immortal *_Nonnull immortal) {
-  return static_cast<const ImmortalBase *>(immortal);
-}
-
-inline const Immortal *_Nonnull castToImmortal(
-    const DerivedFromImmortal *_Nonnull immortal) {
-  return static_cast<const Immortal *>(immortal);
-}
diff --git a/test/Interop/Cxx/class/inheritance/circular-inheritance-typechecker.swift b/test/Interop/Cxx/class/inheritance/circular-inheritance-typechecker.swift
new file mode 100644
index 0000000000000..ec74e7aa87bcb
--- /dev/null
+++ b/test/Interop/Cxx/class/inheritance/circular-inheritance-typechecker.swift
@@ -0,0 +1,23 @@
+// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=default
+
+import CircularInheritance
+
+let voidEgg = VoidEgg()
+voidEgg.dinoEgg()
+voidEgg.voidEgg()
+
+let boolEgg = BoolEgg(false)
+boolEgg.dinoEgg()
+boolEgg.voidEgg()
+boolEgg.chickenEgg(true)
+
+let eggEgg = EggEgg(VoidEgg())
+eggEgg.dinoEgg()
+eggEgg.voidEgg()
+eggEgg.chickenEgg(VoidEgg())
+
+let newEgg = NewEgg()
+newEgg.dinoEgg()
+newEgg.voidEgg()
+newEgg.chickenEgg(555)
+newEgg.newEgg()
diff --git a/test/Interop/Cxx/class/inheritance/fields-irgen.swift b/test/Interop/Cxx/class/inheritance/fields-irgen.swift
index b18a39da3ce7d..7ce5472b0673d 100644
--- a/test/Interop/Cxx/class/inheritance/fields-irgen.swift
+++ b/test/Interop/Cxx/class/inheritance/fields-irgen.swift
@@ -11,4 +11,4 @@ let _ = testGetX()
 
 // CHECK: define {{.*}}linkonce_odr{{.*}} i32 @{{(.*)(30CopyTrackedDerivedDerivedClass33__synthesizedBaseGetterAccessor_x|__synthesizedBaseGetterAccessor_x@CopyTrackedDerivedDerivedClass)(.*)}}(ptr {{.*}} %[[THIS_PTR:.*]])
 // CHECK: %[[ADD_PTR:.*]] = getelementptr inbounds i8, ptr %{{.*}}, i{{32|64}} 4
-// CHECK: %[[X:.*]] = getelementptr inbounds %class.CopyTrackedBaseClass, ptr %[[ADD_PTR]], i32 0, i32 0
+// CHECK: %[[X:.*]] = getelementptr inbounds{{.*}} %class.CopyTrackedBaseClass, ptr %[[ADD_PTR]], i32 0, i32 0
diff --git a/test/Interop/Cxx/class/inheritance/functions-module-interface.swift b/test/Interop/Cxx/class/inheritance/functions-module-interface.swift
index d928744d640ab..4ca095c4a7a20 100644
--- a/test/Interop/Cxx/class/inheritance/functions-module-interface.swift
+++ b/test/Interop/Cxx/class/inheritance/functions-module-interface.swift
@@ -28,8 +28,6 @@
 // CHECK-NEXT:   public static func staticInBase() -> UnsafePointer<CChar>!
 // CHECK-NEXT:   @discardableResult
 // CHECK-NEXT:   public mutating func swiftRenamed(input i: Int32) -> Int32
-// CHECK-NEXT:   @available(swift, obsoleted: 3, renamed: "swiftRenamed(input:)")
-// CHECK-NEXT:   public mutating func renamed(_ i: Int32) -> Int32
 // CHECK-NEXT:   @discardableResult
 // CHECK-NEXT:   @_effects(readonly) public func pure() -> Int32
 // CHECK-NEXT:   @discardableResult
@@ -64,8 +62,6 @@
 // CHECK-NEXT:   public func returnsNonTrivialInBase() -> NonTrivial
 // CHECK-NEXT:   @discardableResult
 // CHECK-NEXT:   public mutating func swiftRenamed(input i: Int32) -> Int32
-// CHECK-NEXT:   @available(swift, obsoleted: 3, renamed: "swiftRenamed(input:)")
-// CHECK-NEXT:   public mutating func renamed(_ i: Int32) -> Int32
 // CHECK-NEXT:   @discardableResult
 // CHECK-NEXT:   @_effects(readonly) public func pure() -> Int32
 // CHECK-NEXT:   @discardableResult
@@ -96,8 +92,6 @@
 // CHECK-NEXT:   public func returnsNonTrivialInBase() -> NonTrivial
 // CHECK-NEXT:   @discardableResult
 // CHECK-NEXT:   public mutating func swiftRenamed(input i: Int32) -> Int32
-// CHECK-NEXT:   @available(swift, obsoleted: 3, renamed: "swiftRenamed(input:)")
-// CHECK-NEXT:   public mutating func renamed(_ i: Int32) -> Int32
 // CHECK-NEXT:   @discardableResult
 // CHECK-NEXT:   @_effects(readonly) public func pure() -> Int32
 // CHECK-NEXT:   @discardableResult
diff --git a/test/Interop/Cxx/class/inheritance/inherited-lookup-executable.swift b/test/Interop/Cxx/class/inheritance/inherited-lookup-executable.swift
index 664c50381f6f5..d6292fc25cd20 100644
--- a/test/Interop/Cxx/class/inheritance/inherited-lookup-executable.swift
+++ b/test/Interop/Cxx/class/inheritance/inherited-lookup-executable.swift
@@ -1,11 +1,26 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -cxx-interoperability-mode=default)
 //
 // REQUIRES: executable_test
+
 import InheritedLookup
 import StdlibUnittest
 
 var InheritedMemberTestSuite = TestSuite("Test if inherited lookup works")
 
+// The compiler handles 
+// - let iiiOne = IIIOne()
+// - struct Foo { let iiiOne : IIIOne } 
+// differently and because of that, by introducing the struct HasOne in this test, 
+// the function importBaseMemberDecl is called twice for each pair of parent-child structs. 
+// The second time, all the structs have a clone version of the method, 
+// which was triggering a "use of ambiguous method" error.
+struct HasOne {
+  let one: One
+  let iOne: IOne
+  let iiOne: IIOne
+  let iiiOne: IIIOne
+}
+
 InheritedMemberTestSuite.test("Regular methods resolve to base classes") {
   // No inheritance (sanity check)
   let one = One()
diff --git a/test/Interop/Cxx/class/inheritance/inherited-lookup-memberimportvisibility.swift b/test/Interop/Cxx/class/inheritance/inherited-lookup-memberimportvisibility.swift
new file mode 100644
index 0000000000000..49e62dea469d0
--- /dev/null
+++ b/test/Interop/Cxx/class/inheritance/inherited-lookup-memberimportvisibility.swift
@@ -0,0 +1,22 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -cxx-interoperability-mode=default -enable-upcoming-feature MemberImportVisibility)
+//
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_MemberImportVisibility
+
+import InheritedLookup
+import StdlibUnittest
+
+var InheritedMemberTestSuite = TestSuite("Test if inherited lookup works")
+
+extension Bar.Derived {
+    public func callBase() {
+        let _ = baseMethod() 
+    }
+}
+
+InheritedMemberTestSuite.test("Look up base methods from extensions") {
+  let a = Bar.Derived()
+  a.callBase()
+}
+
+runAllTests()
diff --git a/test/Interop/Cxx/class/inheritance/inherited-lookup-typechecker.swift b/test/Interop/Cxx/class/inheritance/inherited-lookup-typechecker.swift
index fe6a06cc51167..cad71d779c307 100644
--- a/test/Interop/Cxx/class/inheritance/inherited-lookup-typechecker.swift
+++ b/test/Interop/Cxx/class/inheritance/inherited-lookup-typechecker.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=default
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=default
 import InheritedLookup
 
 extension One {
diff --git a/test/Interop/Cxx/class/inheritance/nested-types-module-interface.swift b/test/Interop/Cxx/class/inheritance/nested-types-module-interface.swift
new file mode 100644
index 0000000000000..201556b074e3e
--- /dev/null
+++ b/test/Interop/Cxx/class/inheritance/nested-types-module-interface.swift
@@ -0,0 +1,67 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=NestedTypes -I %S/Inputs -source-filename=x -cxx-interoperability-mode=default | %FileCheck %s
+
+// CHECK:      struct Base {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   enum EnumClass : CChar {
+// CHECK-NEXT:     init?(rawValue: CChar)
+// CHECK-NEXT:     var rawValue: CChar { get }
+// CHECK-NEXT:     typealias RawValue = CChar
+// CHECK-NEXT:     case eca
+// CHECK-NEXT:     case ecb
+// CHECK-NEXT:     case ecc
+// CHECK-NEXT:   }
+// CHECK-NEXT:   struct Enum : Hashable, Equatable, RawRepresentable {
+// CHECK-NEXT:     init(_ rawValue: {{UInt32|Int32}})
+// CHECK-NEXT:     init(rawValue: {{UInt32|Int32}})
+// CHECK-NEXT:     var rawValue: {{UInt32|Int32}}
+// CHECK-NEXT:     typealias RawValue = {{UInt32|Int32}}
+// CHECK-NEXT:   }
+// CHECK-NEXT:   struct Struct {
+// CHECK-NEXT:     init()
+// CHECK-NEXT:     init(sa: Int32, sb: Int32)
+// CHECK-NEXT:     var sa: Int32
+// CHECK-NEXT:     var sb: Int32
+// CHECK-NEXT:   }
+// CHECK-NEXT:   struct Parent {
+// CHECK-NEXT:     init()
+// CHECK-NEXT:     struct Child {
+// CHECK-NEXT:       init()
+// CHECK-NEXT:       init(pca: Int32)
+// CHECK-NEXT:       var pca: Int32
+// CHECK-NEXT:     }
+// CHECK-NEXT:   }
+// CHECK-NEXT:   struct Union {
+// CHECK-NEXT:     init()
+// CHECK-NEXT:     init(ua: Int32)
+// CHECK-NEXT:     init(ub: Base.Struct)
+// CHECK-NEXT:     var ua: Int32
+// CHECK-NEXT:     var ub: Base.Struct
+// CHECK-NEXT:   }
+// CHECK-NEXT: }
+
+// CHECK:      struct Derived {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   typealias EnumClass = Base.EnumClass
+// CHECK-NEXT:   typealias Enum = Base.Enum
+// CHECK-NEXT:   typealias Struct = Base.Struct
+// CHECK-NEXT:   typealias Parent = Base.Parent
+// CHECK-NEXT:   typealias Union = Base.Union
+// CHECK-NEXT: }
+
+// CHECK:      struct Derived1 {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   typealias EnumClass = Base.EnumClass
+// CHECK-NEXT:   typealias Enum = Base.Enum
+// CHECK-NEXT:   typealias Struct = Base.Struct
+// CHECK-NEXT:   typealias Parent = Base.Parent
+// CHECK-NEXT:   typealias Union = Base.Union
+// CHECK-NEXT: }
+
+// CHECK:      struct Derived2 {
+// CHECK-NEXT:   init()
+// CHECK-NEXT:   typealias EnumClass = Base.EnumClass
+// CHECK-NEXT:   typealias Enum = Base.Enum
+// CHECK-NEXT:   typealias Struct = Base.Struct
+// CHECK-NEXT:   typealias Parent = Base.Parent
+// CHECK-NEXT:   typealias Union = Base.Union
+// CHECK-NEXT: }
diff --git a/test/Interop/Cxx/class/inheritance/nested-types-typechecker.swift b/test/Interop/Cxx/class/inheritance/nested-types-typechecker.swift
new file mode 100644
index 0000000000000..f56f8672d275c
--- /dev/null
+++ b/test/Interop/Cxx/class/inheritance/nested-types-typechecker.swift
@@ -0,0 +1,113 @@
+// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=default
+
+// This test ensures that nested type inherited from the base type are
+// interchangeable with the base types themselves.
+
+import NestedTypes
+
+func parent(
+  bc: Base.EnumClass,
+  be: Base.Enum,
+  bs: Base.Struct,
+  bp: Base.Parent,
+  bpc: Base.Parent.Child,
+  bu: Base.Union,
+) {
+  let dc: Derived.EnumClass = bc
+  let de: Derived.Enum = be
+  let ds: Derived.Struct = bs
+  let dp: Derived.Parent = bp
+  let dpc: Derived.Parent.Child = bpc
+  let du: Derived.Union = bu
+
+  let _: Base.EnumClass = dc
+  let _: Base.Enum = de
+  let _: Base.Struct = ds
+  let _: Base.Parent = dp
+  let _: Base.Parent.Child = dpc
+  let _: Base.Union = du
+}
+
+func grandparent(
+  bc: Base.EnumClass,
+  be: Base.Enum,
+  bs: Base.Struct,
+  bp: Base.Parent,
+  bpc: Base.Parent.Child,
+  bu: Base.Union,
+) {
+  let dc: Derived2.EnumClass = bc
+  let de: Derived2.Enum = be
+  let ds: Derived2.Struct = bs
+  let dp: Derived2.Parent = bp
+  let dpc: Derived2.Parent.Child = bpc
+  let du: Derived2.Union = bu
+
+  let _: Derived.EnumClass = dc
+  let _: Derived.Enum = de
+  let _: Derived.Struct = ds
+  let _: Derived.Parent = dp
+  let _: Derived.Parent.Child = dpc
+  let _: Derived.Union = du
+}
+
+func siblings(
+  dc: Derived.EnumClass,
+  de: Derived.Enum,
+  ds: Derived.Struct,
+  dp: Derived.Parent,
+  dpc: Derived.Parent.Child,
+  du: Derived.Union,
+) {
+  let _: Derived1.EnumClass = dc
+  let _: Derived1.Enum = de
+  let _: Derived1.Struct = ds
+  let _: Derived1.Parent = dp
+  let _: Derived1.Parent.Child = dpc
+  let _: Derived1.Union = du
+}
+
+// Instances created from derived class can be type-annotated with base class
+// and vice versa
+func assigner() {
+  let _: Base.EnumClass = Derived.EnumClass.ecb
+  let _: Base.Enum = Derived.ea // expected-error {{type 'Derived' has no member 'ea'}}
+                                // ^FIXME: nested enums are broken, so inherited nested enums are broken too
+  let _: Base.Struct = Derived.Struct(sa: 4, sb: 2)
+  let _: Base.Parent = Derived.Parent()
+  let _: Base.Parent.Child = Derived.Parent.Child(pca: 42)
+  let _: Base.Union = Derived.Union(ua: 42)
+
+  let _: Derived.EnumClass = Base.EnumClass.ecc
+  let _: Derived.Enum = Base.ea // expected-error {{type 'Base' has no member 'ea'}}
+                                // ^FIXME: nested enums are broken, so inherited nested enums are broken too
+  let _: Derived.Struct = Base.Struct(sa: 4, sb: 2)
+  let _: Derived.Parent = Base.Parent()
+  let _: Derived.Parent.Child = Base.Parent.Child(pca: 42)
+  let _: Derived.Union = Base.Union(ua: 42)
+}
+
+// Extensions on base type should be "seen" in derived types too, and vice versa
+extension Base.Parent {
+  static func getChild1() -> Child {
+    return Child(pca: 111)
+  }
+}
+
+extension Derived {
+  func haveChild1() {
+    let _: Parent.Child = Parent.getChild1()
+  }
+}
+
+extension Derived.Parent {
+  static func getChild2() -> Child {
+    return Child(pca: 111)
+  }
+}
+
+extension Base {
+  func haveChild2() {
+    let _: Parent.Child = Parent.getChild2()
+  }
+}
diff --git a/test/Interop/Cxx/class/inheritance/sub-types-module-interface.swift b/test/Interop/Cxx/class/inheritance/sub-types-module-interface.swift
deleted file mode 100644
index 4029fc7ccb08c..0000000000000
--- a/test/Interop/Cxx/class/inheritance/sub-types-module-interface.swift
+++ /dev/null
@@ -1,49 +0,0 @@
-// RUN: %target-swift-ide-test -print-module -module-to-print=SubTypes -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
-
-// CHECK:      struct Base {
-// CHECK-NEXT:   init()
-// CHECK-NEXT:   enum EnumClass : CChar {
-// CHECK-NEXT:     init?(rawValue: CChar)
-// CHECK-NEXT:     var rawValue: CChar { get }
-// CHECK-NEXT:     typealias RawValue = CChar
-// CHECK-NEXT:     case eca
-// CHECK-NEXT:     case ecb
-// CHECK-NEXT:     case ecc
-// CHECK-NEXT:   }
-// CHECK-NEXT:   struct Enum : Hashable, Equatable, RawRepresentable {
-// CHECK-NEXT:     init(_ rawValue: {{UInt32|Int32}})
-// CHECK-NEXT:     init(rawValue: {{UInt32|Int32}})
-// CHECK-NEXT:     var rawValue: {{UInt32|Int32}}
-// CHECK-NEXT:     typealias RawValue = {{UInt32|Int32}}
-// CHECK-NEXT:   }
-// CHECK-NEXT:   struct Struct {
-// CHECK-NEXT:     init()
-// CHECK-NEXT:     init(sa: Int32, sb: Int32)
-// CHECK-NEXT:     var sa: Int32
-// CHECK-NEXT:     var sb: Int32
-// CHECK-NEXT:   }
-// CHECK-NEXT:   struct Parent {
-// CHECK-NEXT:     init()
-// CHECK-NEXT:     struct Child {
-// CHECK-NEXT:       init()
-// CHECK-NEXT:       init(pca: Int32)
-// CHECK-NEXT:       var pca: Int32
-// CHECK-NEXT:     }
-// CHECK-NEXT:   }
-// CHECK-NEXT:   struct Union {
-// CHECK-NEXT:     init()
-// CHECK-NEXT:     init(ua: Int32)
-// CHECK-NEXT:     init(ub: Base.Struct)
-// CHECK-NEXT:     var ua: Int32
-// CHECK-NEXT:     var ub: Base.Struct
-// CHECK-NEXT:   }
-// CHECK-NEXT: }
-
-// CHECK-NEXT: struct Derived {
-// CHECK-NEXT:   init()
-// CHECK-NEXT:   typealias EnumClass = Base.EnumClass.Type
-// CHECK-NEXT:   typealias Enum = Base.Enum.Type
-// CHECK-NEXT:   typealias Struct = Base.Struct.Type
-// CHECK-NEXT:   typealias Parent = Base.Parent.Type
-// CHECK-NEXT:   typealias Union = Base.Union.Type
-// CHECK-NEXT: }
diff --git a/test/Interop/Cxx/class/inheritance/type-aliases-module-interface.swift b/test/Interop/Cxx/class/inheritance/type-aliases-module-interface.swift
index 4dde31f117869..66a28d63424ef 100644
--- a/test/Interop/Cxx/class/inheritance/type-aliases-module-interface.swift
+++ b/test/Interop/Cxx/class/inheritance/type-aliases-module-interface.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-ide-test -print-module -module-to-print=TypeAliases -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -module-to-print=TypeAliases -I %S/Inputs -source-filename=x -cxx-interoperability-mode=default | %FileCheck %s
 
 // CHECK:      struct Base {
 // CHECK-NEXT:   init()
@@ -11,7 +11,7 @@
 
 // CHECK-NEXT: struct Derived {
 // CHECK-NEXT:   init()
-// CHECK-NEXT:   typealias Struct = Base.Struct.Type
+// CHECK-NEXT:   typealias Struct = Base.Struct
 // CHECK-NEXT:   typealias T = Int32
 // CHECK-NEXT:   typealias U = Base.Struct
 // CHECK-NEXT: }
diff --git a/test/Interop/Cxx/class/inheritance/type-aliases-typechecker.swift b/test/Interop/Cxx/class/inheritance/type-aliases-typechecker.swift
new file mode 100644
index 0000000000000..a59bc3e3cfedb
--- /dev/null
+++ b/test/Interop/Cxx/class/inheritance/type-aliases-typechecker.swift
@@ -0,0 +1,51 @@
+// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=default
+
+// This test ensures that nested type aliases inherited from the base type are 
+// interchangeable with the base types themselves.
+
+import TypeAliases
+
+extension Derived {
+  func takesBaseTypes(bs: Base.Struct, bt: Base.T, bu: Base.U) {
+    let _: Struct = bs
+    let _: U = bs
+
+    let _: T = bt
+    let _: Int32 = bt
+    
+    let _: U = bu
+    let _: Struct = bu
+  }
+
+  func takesDerivedTypes(ds: Struct, dt: T, du: U) {
+    let _: Base.Struct = ds
+    let _: Base.U = ds
+
+    let _: Base.T = dt
+    let _: Int32 = dt
+    
+    let _: Base.U = du
+    let _: Base.Struct = du
+  }
+}
+func takesBaseTypes(bs: Base.Struct, bt: Base.T, bu: Base.U) {
+  let _: Derived.Struct = bs
+  let _: Derived.U = bs
+
+  let _: Derived.T = bt
+  let _: Int32 = bt
+  
+  let _: Derived.U = bu
+  let _: Derived.Struct = bu
+}
+
+func takesDerivedTypes(ds: Derived.Struct, dt: Derived.T, du: Derived.U) {
+  let _: Base.Struct = ds
+  let _: Base.U = ds
+
+  let _: Base.T = dt
+  let _: Int32 = dt
+  
+  let _: Base.U = du
+  let _: Base.Struct = du
+}
diff --git a/test/Interop/Cxx/class/inheritance/using-base-members-module-interface.swift b/test/Interop/Cxx/class/inheritance/using-base-members-module-interface.swift
index 5d68b5de4ae3b..0d72a52ead537 100644
--- a/test/Interop/Cxx/class/inheritance/using-base-members-module-interface.swift
+++ b/test/Interop/Cxx/class/inheritance/using-base-members-module-interface.swift
@@ -48,8 +48,6 @@
 // CHECK-NEXT: }
 
 // CHECK:      public struct UsingBaseConstructorWithParam {
-// CHECK-NEXT:   public init(consuming _: consuming IntBox)
-// CHECK-NEXT:   public init(_: IntBox)
 // CHECK-NEXT:   public init(_: UInt32)
 // CHECK-NEXT:   public init(_: Int32)
 // CHECK-NEXT:   public var value: Int32
@@ -57,8 +55,6 @@
 
 // CHECK:      public struct UsingBaseConstructorEmpty {
 // CHECK-NEXT:   public init()
-// CHECK-NEXT:   public init(consuming _: consuming Empty)
-// CHECK-NEXT:   public init(_: Empty)
 // CHECK-NEXT:   public var value: Int32
 // CHECK-NEXT: }
 
diff --git a/test/Interop/Cxx/class/inheritance/using-base-members-typechecker.swift b/test/Interop/Cxx/class/inheritance/using-base-members-typechecker.swift
index f417fa935867c..2fb90d49ecac9 100644
--- a/test/Interop/Cxx/class/inheritance/using-base-members-typechecker.swift
+++ b/test/Interop/Cxx/class/inheritance/using-base-members-typechecker.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=default -enable-experimental-feature ImportNonPublicCxxMembers
 // REQUIRES: swift_feature_ImportNonPublicCxxMembers
 
 import UsingBaseMembers
diff --git a/test/Interop/Cxx/class/inheritance/virtual-methods-module-interface.swift b/test/Interop/Cxx/class/inheritance/virtual-methods-module-interface.swift
index 9c7513010f4ac..641f4774deff9 100644
--- a/test/Interop/Cxx/class/inheritance/virtual-methods-module-interface.swift
+++ b/test/Interop/Cxx/class/inheritance/virtual-methods-module-interface.swift
@@ -7,6 +7,7 @@
 // CHECK-NEXT:   init()
 // CHECK-NEXT:   @available(*, unavailable, message: "virtual function is not available in Swift because it is pure")
 // CHECK-NEXT:   mutating func foo()
+// CHECK-NEXT:   func swiftVirtualRename()
 // CHECK: }
 
 // CHECK: struct Base3 {
@@ -25,12 +26,3 @@
 // CHECK: struct VirtualNonAbstractBase {
 // CHECK-NEXT:  init()
 // CHECK-NEXT:  func nonAbstractMethod()
-
-// CHECK: class ImmortalBase {
-// CHECK:  func get42() -> Int32
-// CHECK:  func getOverridden42() -> Int32
-// CHECK: }
-// CHECK: class Immortal {
-// CHECK:  func getOverridden42() -> Int32
-// CHECK:  func get42() -> Int32
-// CHECK: }
diff --git a/test/Interop/Cxx/class/inheritance/virtual-methods-typechecker.swift b/test/Interop/Cxx/class/inheritance/virtual-methods-typechecker.swift
index 747bbfcb5589d..2cbc04c3f1988 100644
--- a/test/Interop/Cxx/class/inheritance/virtual-methods-typechecker.swift
+++ b/test/Interop/Cxx/class/inheritance/virtual-methods-typechecker.swift
@@ -1,6 +1,6 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-5.9
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-6
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-5.9
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-6
 
 import VirtualMethods
 
@@ -15,25 +15,7 @@ let _ = DerivedFromDerived2()
 
 VirtualNonAbstractBase().nonAbstractMethod()
 
-@available(SwiftStdlib 5.8, *)
-func takesImmortalBase(_ i: ImmortalBase) {
-  let _ = i.get42()
-  let _ = i.getOverridden42()
-  let _ = i.getIntValue()
-}
-
-@available(SwiftStdlib 5.8, *)
-func takesImmortal(_ i: Immortal) {
-  let _ = i.get42()
-  let _ = i.getOverridden42()
-  let _ = i.getIntValue()
-  i.setIntValue(1)
-}
-
-@available(SwiftStdlib 5.8, *)
-func takesDerivedFromImmortal(_ i: DerivedFromImmortal) {
-  let _ = i.get42()
-  let _ = i.getOverridden42()
-  let _ = i.getIntValue()
-  i.setIntValue(1)
+func callVirtualRenamedMethod(_ b: Base) {
+  b.virtualRename()  // expected-error {{value of type 'Base' has no member 'virtualRename'}}
+  b.swiftVirtualRename()
 }
diff --git a/test/Interop/Cxx/class/inheritance/virtual-methods.swift b/test/Interop/Cxx/class/inheritance/virtual-methods.swift
index e5c7638ee1f80..d91f43e5155bf 100644
--- a/test/Interop/Cxx/class/inheritance/virtual-methods.swift
+++ b/test/Interop/Cxx/class/inheritance/virtual-methods.swift
@@ -29,39 +29,4 @@ VirtualMethodsTestSuite.test("value type") {
   expectEqual(789, d6.getPureInt())
 }
 
-if #available(SwiftStdlib 5.8, *) {
-  VirtualMethodsTestSuite.test("immortal reference type") {
-    let i = Immortal.create()
-    expectEqual(42, i.get42())
-    expectEqual(0, i.getIntValue())
-
-    let base = castToImmortalBase(i)
-    expectEqual(42, base.get42())
-    expectEqual(42, base.getOverridden42())
-    expectEqual(0, base.getIntValue())
-
-    i.setIntValue(566)
-    expectEqual(566, i.getIntValue())
-    expectEqual(566, base.getIntValue())
-
-    let d = DerivedFromImmortal.create()
-    expectEqual(42, d.get42())
-    expectEqual(42, d.getOverridden42())
-    d.setIntValue(321)
-    expectEqual(321, d.getIntValue())
-    let base2 = castToImmortalBase(castToImmortal(d))
-    expectEqual(321, base2.getIntValue())
-  }
-}
-
-#if !os(Windows) 
-// FIXME in Windows, non-trivial C++ class with trivial ABI is not yet available in Swift
-VirtualMethodsTestSuite.test("C++ virtual method with complex parameter") {
-  @available(SwiftStdlib 5.8, *)
-  func f(simpleClass: HasDestructor, immortalClass: Immortal2) {
-    immortalClass.virtualMethod(simpleClass)
-  }
-}
-#endif
-
 runAllTests()
diff --git a/test/Interop/Cxx/class/invalid-unsafe-projection-errors.swift b/test/Interop/Cxx/class/invalid-unsafe-projection-errors.swift
index 6893d36794d14..8b5d82871c7cb 100644
--- a/test/Interop/Cxx/class/invalid-unsafe-projection-errors.swift
+++ b/test/Interop/Cxx/class/invalid-unsafe-projection-errors.swift
@@ -23,6 +23,11 @@ struct M {
   StringLiteral stringLiteral() const { return StringLiteral{"M"}; }
 };
 
+struct HasNonIteratorBeginMethod {
+  void begin() const;
+  void end() const;
+};
+
 //--- test.swift
 
 import Test
@@ -48,3 +53,8 @@ public func test(x: M) {
   // CHECK-NOT: error: value of type 'M' has no member 'stringLiteral'
   x.stringLiteral()
 }
+
+public func test(_ x: HasNonIteratorBeginMethod) {
+  x.begin()
+  x.end()
+}
diff --git a/test/Interop/Cxx/class/memory-layout-silgen.swift b/test/Interop/Cxx/class/memory-layout-silgen.swift
index d56a3ee81d2f5..22afb63089844 100644
--- a/test/Interop/Cxx/class/memory-layout-silgen.swift
+++ b/test/Interop/Cxx/class/memory-layout-silgen.swift
@@ -8,5 +8,5 @@ var v = PrivateMemberLayout()
 // words, we use Clang's, not Swift's view of the class to compute the memory
 // layout.
 // The important point here is that the second index is 1, not 0.
-// CHECK: store i32 42, ptr getelementptr inbounds (%TSo19PrivateMemberLayoutV, ptr @"$s4main1vSo19PrivateMemberLayoutVvp", i32 0, i32 1), align 4
+// CHECK: store i32 42, ptr getelementptr inbounds{{.*}} (%TSo19PrivateMemberLayoutV, ptr @"$s4main1vSo19PrivateMemberLayoutVvp", i32 0, i32 1), align 4
 v.b = 42
diff --git a/test/Interop/Cxx/class/method/Inputs/deducing-this.h b/test/Interop/Cxx/class/method/Inputs/deducing-this.h
new file mode 100644
index 0000000000000..35bdd29c7357d
--- /dev/null
+++ b/test/Interop/Cxx/class/method/Inputs/deducing-this.h
@@ -0,0 +1,4 @@
+struct HasDeducingThis {
+  int value;
+  int deducingRef(this HasDeducingThis &self) { return self.value; }
+};
diff --git a/test/Interop/Cxx/class/method/Inputs/module.modulemap b/test/Interop/Cxx/class/method/Inputs/module.modulemap
index 9a27e5c97da9e..20e8fb1d94dc1 100644
--- a/test/Interop/Cxx/class/method/Inputs/module.modulemap
+++ b/test/Interop/Cxx/class/method/Inputs/module.modulemap
@@ -1,3 +1,8 @@
+module DeducingThis {
+  header "deducing-this.h"
+  requires cplusplus23
+}
+
 module Methods {
   header "methods.h"
   requires cplusplus
diff --git a/test/Interop/Cxx/class/method/deducing-this-module-interface.swift b/test/Interop/Cxx/class/method/deducing-this-module-interface.swift
new file mode 100644
index 0000000000000..324333d8809a5
--- /dev/null
+++ b/test/Interop/Cxx/class/method/deducing-this-module-interface.swift
@@ -0,0 +1,6 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=DeducingThis -I %S/Inputs -source-filename=x -cxx-interoperability-mode=upcoming-swift -Xcc -std=c++23 | %FileCheck %s
+
+// This mostly ensures that we don't import deducing this method with an incorrect signature.
+
+// CHECK: struct HasDeducingThis {
+// CHECK-NOT:   deducingRef
diff --git a/test/Interop/Cxx/class/method/inreg-sret.swift b/test/Interop/Cxx/class/method/inreg-sret.swift
index b11bc95fe3c68..47be2c24309d4 100644
--- a/test/Interop/Cxx/class/method/inreg-sret.swift
+++ b/test/Interop/Cxx/class/method/inreg-sret.swift
@@ -21,8 +21,8 @@ final public class Function {
 
 // Check that inreg on the sret isn't missing
 
-// CHECK-x86_64: call void @"?getFirstBlock@BridgedFunction@@QEBA?AUOptionalBridgedBasicBlock@@XZ"(ptr {{.*}}, ptr noalias nocapture sret(%TSo25OptionalBridgedBasicBlockV) {{.*}})
-// CHECK-aarch64: call void @"?getFirstBlock@BridgedFunction@@QEBA?AUOptionalBridgedBasicBlock@@XZ"(ptr {{.*}}, ptr inreg noalias nocapture sret(%TSo25OptionalBridgedBasicBlockV) {{.*}})
+// CHECK-x86_64: call void @"?getFirstBlock@BridgedFunction@@QEBA?AUOptionalBridgedBasicBlock@@XZ"(ptr {{.*}}, ptr noalias{{( nocapture)?}} sret(%TSo25OptionalBridgedBasicBlockV){{( captures\(none\))?}} {{.*}})
+// CHECK-aarch64: call void @"?getFirstBlock@BridgedFunction@@QEBA?AUOptionalBridgedBasicBlock@@XZ"(ptr {{.*}}, ptr inreg noalias{{( nocapture)?}} sret(%TSo25OptionalBridgedBasicBlockV){{( captures\(none\))?}} {{.*}})
 
 // CHECK-x86_64: define {{.*}} void @"?getFirstBlock@BridgedFunction@@QEBA?AUOptionalBridgedBasicBlock@@XZ"(ptr {{.*}} %{{.*}}, ptr {{.*}} sret(%struct.OptionalBridgedBasicBlock) {{.*}} %{{.*}})
 // CHECK-aarch64: define {{.*}} void @"?getFirstBlock@BridgedFunction@@QEBA?AUOptionalBridgedBasicBlock@@XZ"(ptr {{.*}} %{{.*}}, ptr inreg {{.*}} sret(%struct.OptionalBridgedBasicBlock) {{.*}} %{{.*}})
diff --git a/test/Interop/Cxx/class/method/methods-addressable-dependency.swift b/test/Interop/Cxx/class/method/methods-addressable-dependency.swift
new file mode 100644
index 0000000000000..fd8c6f634ad36
--- /dev/null
+++ b/test/Interop/Cxx/class/method/methods-addressable-dependency.swift
@@ -0,0 +1,29 @@
+// This ensures that a Swift module built without AddressableParameters can be
+// consumed by a dependency Swift module that enables AddressableParameters.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+// RUN: %target-build-swift %t/library.swift -emit-module -emit-library -enable-library-evolution -cxx-interoperability-mode=upcoming-swift -module-name MyLibrary -emit-module-path %t/artifacts/MyLibrary.swiftmodule -emit-module-interface-path %t/artifacts/MyLibrary.swiftinterface -I %S/Inputs -swift-version 6 -enable-experimental-feature AssumeResilientCxxTypes
+// RUN: rm %t/artifacts/MyLibrary.swiftmodule
+// RUN: %target-build-swift %t/executable.swift -emit-irgen -cxx-interoperability-mode=default -module-name ImportsMyLibrary -I %t/artifacts -I %S/Inputs -swift-version 6 -enable-experimental-feature AssumeResilientCxxTypes -enable-experimental-feature AddressableParameters
+
+// REQUIRES: swift_feature_AddressableParameters
+// REQUIRES: swift_feature_AssumeResilientCxxTypes
+
+//--- library.swift
+import Methods
+
+@inlinable // emit the body of the function into the textual interface
+public func addressableTest(_ x: borrowing NonTrivialInWrapper) {
+  let m = HasMethods()
+  m.nonTrivialTakesConstRef(x)
+}
+
+//--- executable.swift
+import MyLibrary
+import Methods
+
+let x = NonTrivialInWrapper(123)
+let m = HasMethods()
+m.nonTrivialTakesConstRef(x)
diff --git a/test/Interop/Cxx/class/method/methods-addressable-silgen.swift b/test/Interop/Cxx/class/method/methods-addressable-silgen.swift
index 485851edae2fe..4578263e46df8 100644
--- a/test/Interop/Cxx/class/method/methods-addressable-silgen.swift
+++ b/test/Interop/Cxx/class/method/methods-addressable-silgen.swift
@@ -17,7 +17,7 @@ public func addressableTest(x: borrowing @_addressable NonTrivialInWrapper, y: i
   // CHECK: %{{[0-9]+}} = apply %{{[0-9]+}}([[UNWRAPPED]], %{{[0-9]+}}) : $@convention(cxx_method) (@in_guaranteed NonTrivialInWrapper, @in_guaranteed HasMethods) -> ()
   var m2 = HasMethods()
   // CHECK: [[ACCESS:%[0-9]+]] = begin_access [modify] [unknown] [[INPUT2]]
-  // CHECK: %{{[0-9]+}} = apply %32([[ACCESS]], %{{[0-9]+}}) : $@convention(cxx_method) (@inout NonTrivialInWrapper, @in_guaranteed HasMethods) -> ()
+  // CHECK: %{{[0-9]+}} = apply %{{[0-9]+}}([[ACCESS]], %{{[0-9]+}}) : $@convention(cxx_method) (@inout NonTrivialInWrapper, @in_guaranteed HasMethods) -> ()
   // CHECK-NEXT: end_access [[ACCESS]]
   m2.nonTrivialTakesRef(&y)
 }
diff --git a/test/Interop/Cxx/class/method/msvc-abi-return-indirect-trivial-record.swift b/test/Interop/Cxx/class/method/msvc-abi-return-indirect-trivial-record.swift
index ebc02d41c1ecf..001fccc59c594 100644
--- a/test/Interop/Cxx/class/method/msvc-abi-return-indirect-trivial-record.swift
+++ b/test/Interop/Cxx/class/method/msvc-abi-return-indirect-trivial-record.swift
@@ -67,5 +67,5 @@ public func passTempForIndirectRetToVoidCall() {
 
 // CHECK: i32 @"$sSo18LoadableIntWrapperV2peoiyA2Bz_ABtFZ"(ptr
 // CHECK: %[[OPRESULT:.*]] = alloca %TSo18LoadableIntWrapperV, align 4
-// CHECK-x86_64: call void @"??YLoadableIntWrapper@@QEAA?AU0@U0@@Z"(ptr {{.*}}, ptr {{.*}} sret(%TSo18LoadableIntWrapperV) %[[OPRESULT]], i32
-// CHECK-aarch64: call void @"??YLoadableIntWrapper@@QEAA?AU0@U0@@Z"(ptr {{.*}}, ptr {{.*}} sret(%TSo18LoadableIntWrapperV) %[[OPRESULT]], i64
+// CHECK-x86_64: call void @"??YLoadableIntWrapper@@QEAA?AU0@U0@@Z"(ptr {{.*}}, ptr {{.*}} sret(%TSo18LoadableIntWrapperV){{.*}} %[[OPRESULT]], i32
+// CHECK-aarch64: call void @"??YLoadableIntWrapper@@QEAA?AU0@U0@@Z"(ptr {{.*}}, ptr {{.*}} sret(%TSo18LoadableIntWrapperV){{.*}} %[[OPRESULT]], i64
diff --git a/test/Interop/Cxx/class/mirror.swift b/test/Interop/Cxx/class/mirror.swift
new file mode 100644
index 0000000000000..8b004a3946a4c
--- /dev/null
+++ b/test/Interop/Cxx/class/mirror.swift
@@ -0,0 +1,97 @@
+// RUN: %target-run-simple-swift(-cxx-interoperability-mode=default -I %S/Inputs)
+
+// REQUIRES: executable_test
+// Metadata for foreign reference types is not supported on Windows.
+// UNSUPPORTED: OS=windows-msvc
+
+import StdlibUnittest
+import Mirror
+
+var MirrorTestSuite = TestSuite("Mirrors")
+
+MirrorTestSuite.test("EmptyCxxStruct") {
+  let s = EmptyStruct()
+  let m = Mirror(reflecting: s)
+  expectEqual(.`struct`, m.displayStyle)
+  expectTrue(m.subjectType == EmptyStruct.self)
+  expectEqual(0, m.children.count)
+
+  var output = ""
+  dump(s, to: &output)
+  expectEqual("- __C.EmptyStruct\n", output)
+}
+
+MirrorTestSuite.test("EmptyCxxClass") {
+  let s = EmptyClass()
+  let m = Mirror(reflecting: s)
+  expectEqual(.`struct`, m.displayStyle)
+  expectTrue(m.subjectType == EmptyClass.self)
+  expectEqual(0, m.children.count)
+
+  var output = ""
+  dump(s, to: &output)
+  expectEqual("- __C.EmptyClass\n", output)
+}
+
+MirrorTestSuite.test("CxxStructWithFields") {
+  let s = BaseStruct(1, 2, 3)
+  let m = Mirror(reflecting: s)
+  expectEqual(.`struct`, m.displayStyle)
+  expectTrue(m.subjectType == BaseStruct.self)
+  expectEqual(1, m.children.count)
+
+  expectEqual("publ", m.children.first!.label)
+  expectEqual(2, m.children.first!.value as? Int32)
+  
+  var output = ""
+  dump(s, to: &output)
+  let expected = 
+    "▿ __C.BaseStruct\n" +
+    "  - publ: 2\n"
+  expectEqual(expected, output)
+}
+
+MirrorTestSuite.test("CxxStructWithStructsAsFields") {
+  let s = OuterStruct()
+  let m = Mirror(reflecting: s)
+  expectEqual(.`struct`, m.displayStyle)
+  expectTrue(m.subjectType == OuterStruct.self)
+  expectEqual(1, m.children.count)
+  expectEqual("publStruct", m.children.first!.label)
+  
+  var output = ""
+  dump(s, to: &output)
+  let expected = 
+    "▿ __C.OuterStruct\n" +
+    "  ▿ publStruct: __C.BaseStruct\n" +
+    "    - publ: 5\n"    
+  expectEqual(expected, output)
+}
+
+if #available(SwiftStdlib 6.2, *) {
+  MirrorTestSuite.test("CxxFRTStruct") {
+    let s = FRTStruct()
+    let m = Mirror(reflecting: s)
+    expectEqual(.foreignReference, m.displayStyle)
+    expectTrue(m.subjectType == FRTStruct.self)
+    expectEqual(0, m.children.count)
+
+    var output = ""
+    dump(s, to: &output)
+    expectEqual("- __C.FRTStruct\n", output)
+  }
+
+  MirrorTestSuite.test("CxxFRTImmortalClass") {
+    let s = FRTImmortalClass()
+    let m = Mirror(reflecting: s)
+    expectEqual(.foreignReference, m.displayStyle)
+    expectTrue(m.subjectType == FRTImmortalClass.self)
+    expectEqual(0, m.children.count)
+
+    var output = ""
+    dump(s, to: &output)
+    expectEqual("- __C.FRTImmortalClass\n", output)
+  }
+}
+
+runAllTests()
diff --git a/test/Interop/Cxx/class/move-only/Inputs/move-only-cxx-value-type.h b/test/Interop/Cxx/class/move-only/Inputs/move-only-cxx-value-type.h
index 388a686dd233c..16c4f1bf65504 100644
--- a/test/Interop/Cxx/class/move-only/Inputs/move-only-cxx-value-type.h
+++ b/test/Interop/Cxx/class/move-only/Inputs/move-only-cxx-value-type.h
@@ -56,4 +56,16 @@ struct NonCopyableHolderDerivedDerived: NonCopyableHolderDerived {
 inline NonCopyable *getNonCopyablePtr() { return nullptr; }
 inline NonCopyableDerived *getNonCopyableDerivedPtr() { return nullptr; }
 
+template <typename T>
+struct FieldInAnonStruct {
+  FieldInAnonStruct() : field(5) {}
+  FieldInAnonStruct(const FieldInAnonStruct &) = delete;
+  FieldInAnonStruct(FieldInAnonStruct &&) = default;
+  struct {
+    T field;
+  };
+};
+
+using FieldInAnonStructNC = FieldInAnonStruct<NonCopyable>;
+
 #endif // TEST_INTEROP_CXX_CLASS_MOVE_ONLY_VT_H
diff --git a/test/Interop/Cxx/class/move-only/inherited-field-access-irgen.swift b/test/Interop/Cxx/class/move-only/inherited-field-access-irgen.swift
index 75643f9261883..8152635fa8d32 100644
--- a/test/Interop/Cxx/class/move-only/inherited-field-access-irgen.swift
+++ b/test/Interop/Cxx/class/move-only/inherited-field-access-irgen.swift
@@ -18,9 +18,9 @@ func testSetX(_ x: CInt) {
 testSetX(2)
 
 // CHECK: define {{.*}}linkonce_odr{{.*}} ptr @{{(.*)(31NonCopyableHolderDerivedDerived*33__synthesizedBaseGetterAccessor_x|__synthesizedBaseGetterAccessor_x@NonCopyableHolderDerivedDerived)(.*)}}
-// CHECK: %[[VPTR:.*]] = getelementptr inbounds %struct.NonCopyableHolder
+// CHECK: %[[VPTR:.*]] = getelementptr inbounds{{.*}} %struct.NonCopyableHolder
 // CHECK: ret ptr %[[VPTR]]
 
 // CHECK: define {{.*}}linkonce_odr{{.*}} ptr @{{(.*)(31NonCopyableHolderDerivedDerived33__synthesizedBaseSetterAccessor_x|__synthesizedBaseSetterAccessor_x@NonCopyableHolderDerivedDerived)(.*)}}
-// CHECK: %[[VPTRS:.*]] = getelementptr inbounds %struct.NonCopyableHolder
+// CHECK: %[[VPTRS:.*]] = getelementptr inbounds{{.*}} %struct.NonCopyableHolder
 // CHECK: ret ptr %[[VPTRS]]
diff --git a/test/Interop/Cxx/class/move-only/move-only-cxx-value-type.swift b/test/Interop/Cxx/class/move-only/move-only-cxx-value-type.swift
index a9ccb692a3431..0e5c8098e5e0b 100644
--- a/test/Interop/Cxx/class/move-only/move-only-cxx-value-type.swift
+++ b/test/Interop/Cxx/class/move-only/move-only-cxx-value-type.swift
@@ -1,8 +1,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift)
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift -D HAS_NONCOPYABLE_GENERICS)
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-5.9 -O)
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-6 -O)
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-6 -O -D HAS_NONCOPYABLE_GENERICS)
 
 // REQUIRES: executable_test
 
@@ -29,12 +27,10 @@ MoveOnlyCxxValueType.test("Test derived move only type member access") {
   var k = c.method(-3)
   expectEqual(k, -6)
   expectEqual(c.method(1), 2)
-#if HAS_NONCOPYABLE_GENERICS
   k = c.x
   expectEqual(k, 2)
   c.x = 11
   expectEqual(c.x, 11)
-#endif
   k = c.mutMethod(-13)
   expectEqual(k, -13)
 }
@@ -60,7 +56,6 @@ MoveOnlyCxxValueType.test("Test move only field access in holder") {
   expectEqual(c.x.x, 5)
 }
 
-#if HAS_NONCOPYABLE_GENERICS
 MoveOnlyCxxValueType.test("Test move only field access in derived holder") {
   var c = NonCopyableHolderDerivedDerived(-11)
   var k = borrowNC(c.x)
@@ -74,6 +69,9 @@ MoveOnlyCxxValueType.test("Test move only field access in derived holder") {
   c.x.mutMethod(5)
   expectEqual(c.x.x, 5)
 }
-#endif
 
+MoveOnlyCxxValueType.test("Test move only field in anonymous struct") {
+  let a = FieldInAnonStructNC()
+  let b = a
+}
 runAllTests()
diff --git a/test/Interop/Cxx/class/mutability-annotations-typechecker.swift b/test/Interop/Cxx/class/mutability-annotations-typechecker.swift
index c2bf9ceac4b7a..d2737aca20fcb 100644
--- a/test/Interop/Cxx/class/mutability-annotations-typechecker.swift
+++ b/test/Interop/Cxx/class/mutability-annotations-typechecker.swift
@@ -1,6 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs %s -enable-experimental-cxx-interop -verify -verify-additional-file %S/Inputs/mutability-annotations.h
-
-// REQUIRES: rdar100876534
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S%{fs-sep}Inputs %s -enable-experimental-cxx-interop -verify -verify-additional-file %S%{fs-sep}Inputs%{fs-sep}mutability-annotations.h
 
 import MutabilityAnnotations
 
diff --git a/test/Interop/Cxx/class/noncopyable-irgen.swift b/test/Interop/Cxx/class/noncopyable-irgen.swift
new file mode 100644
index 0000000000000..a4928a93b2ae3
--- /dev/null
+++ b/test/Interop/Cxx/class/noncopyable-irgen.swift
@@ -0,0 +1,112 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -cxx-interoperability-mode=default -emit-ir -I %swift_src_root/lib/ClangImporter/SwiftBridging -I %t%{fs-sep}Inputs %t%{fs-sep}test.swift -Xcc -fignore-exceptions -verify -verify-additional-file %t%{fs-sep}Inputs%{fs-sep}noncopyable.h -verify-additional-prefix TEST1- -D TEST1
+// RUN: %target-swift-frontend -cxx-interoperability-mode=default -emit-ir -I %swift_src_root/lib/ClangImporter/SwiftBridging -I %t%{fs-sep}Inputs %t%{fs-sep}test.swift -Xcc -fignore-exceptions -verify -verify-additional-file %t%{fs-sep}Inputs%{fs-sep}noncopyable.h -verify-additional-prefix TEST2- -D TEST2
+// RUN: %target-swift-frontend -cxx-interoperability-mode=default -emit-ir -I %swift_src_root/lib/ClangImporter/SwiftBridging -I %t%{fs-sep}Inputs %t%{fs-sep}test.swift -Xcc -fignore-exceptions -verify -verify-additional-file %t%{fs-sep}Inputs%{fs-sep}noncopyable.h -verify-additional-prefix TEST3- -D TEST3
+// RUN: %target-swift-frontend -cxx-interoperability-mode=default -emit-ir -I %swift_src_root/lib/ClangImporter/SwiftBridging -I %t%{fs-sep}Inputs %t%{fs-sep}test.swift -Xcc -fignore-exceptions -verify -verify-additional-file %t%{fs-sep}Inputs%{fs-sep}noncopyable.h -verify-additional-prefix TEST4- -D TEST4 -Xcc -std=c++20
+
+//--- Inputs/module.modulemap
+module Test {
+    header "noncopyable.h"
+    requires cplusplus
+}
+
+//--- Inputs/noncopyable.h
+#include "swift/bridging"
+#include <string>
+
+struct NonCopyable {
+    NonCopyable() = default;
+    NonCopyable(const NonCopyable& other) = delete; // expected-note {{'NonCopyable' has been explicitly marked deleted here}}
+    NonCopyable(NonCopyable&& other) = default;
+};
+
+template <typename T>
+struct OwnsT {
+    T element;
+    OwnsT() {}
+    OwnsT(const OwnsT &other) : element(other.element) {} 
+    // expected-error@-1 *{{call to deleted constructor of 'NonCopyable'}}
+    // expected-note@-2 *{{in instantiation of member function 'OwnsT<NonCopyable>::OwnsT' requested here}}
+    // expected-TEST1-error@-3 {{failed to copy 'OwnsT<NonCopyable>'; did you mean to import 'OwnsT<NonCopyable>' as ~Copyable?}}
+    // expected-TEST1-note@-4 {{use 'requires' (since C++20) to specify the constraints under which the copy constructor is available}}
+    // expected-TEST1-note@-5 {{annotate a type with 'SWIFT_COPYABLE_IF(<T>)' in C++ to specify that the type is Copyable if <T> is Copyable}}
+    OwnsT(OwnsT&& other) {}
+};
+
+using OwnsNonCopyable = OwnsT<NonCopyable>;
+
+template <typename T> struct Derived : OwnsT<T> {
+    // expected-TEST2-error@-1 {{failed to copy 'Derived<NonCopyable>'; did you mean to import 'Derived<NonCopyable>' as ~Copyable?}}
+    // expected-TEST2-note@-2 {{use 'requires' (since C++20) to specify the constraints under which the copy constructor is available}}
+    // expected-TEST2-note@-3 {{annotate a type with 'SWIFT_COPYABLE_IF(<T>)' in C++ to specify that the type is Copyable if <T> is Copyable}}
+    // expected-TEST2-note@-4 {{annotate a type with 'SWIFT_NONCOPYABLE' in C++ to import it as ~Copyable}}
+};
+
+using DerivedNonCopyable = Derived<NonCopyable>;
+
+template <typename T> struct SWIFT_COPYABLE_IF(T) Annotated {
+    T element;
+    Annotated() : element() {}
+    Annotated(const Annotated &other) : element(other.element) {}
+    // expected-TEST3-error@-1 {{failed to copy 'Annotated<OwnsT<NonCopyable>>'; did you mean to import 'Annotated<OwnsT<NonCopyable>>' as ~Copyable?}}
+    // expected-TEST3-note@-2 {{one of the types that 'Annotated<OwnsT<NonCopyable>>' depends on may need a 'requires' clause (since C++20) in the copy constructor, a 'SWIFT_COPYABLE_IF' annotation or a 'SWIFT_NONCOPYABLE' annotation'}}
+    // expected-TEST3-note@-3 {{the 'SWIFT_COPYABLE_IF' annotation on 'Annotated<OwnsT<NonCopyable>>' may be missing a parameter}}
+
+    Annotated(Annotated &&) = default;
+};
+
+using AnnotatedOwnsNonCopyable = Annotated<OwnsT<NonCopyable>>;
+
+#if __cplusplus >= 202002L
+template <typename T> struct Requires {
+    T element;
+    Requires() : element() {}
+    Requires(const Requires &other) requires std::is_copy_constructible_v<T> : element(other.element) {}
+    // expected-TEST4-error@-1 {{failed to copy 'Requires<OwnsT<NonCopyable>>'; did you mean to import 'Requires<OwnsT<NonCopyable>>' as ~Copyable?}}
+    // expected-TEST4-note@-2 {{one of the types that 'Requires<OwnsT<NonCopyable>>' depends on may need a 'requires' clause (since C++20) in the copy constructor, a 'SWIFT_COPYABLE_IF' annotation or a 'SWIFT_NONCOPYABLE' annotation'}}
+    // expected-TEST4-note@-3 {{the 'requires' clause on the copy constructor of 'Requires<OwnsT<NonCopyable>>' may be missing a constraint}}
+
+    Requires(Requires &&) = default;
+};
+
+using RequiresOwnsNonCopyable = Requires<OwnsT<NonCopyable>>;
+#endif
+
+//--- test.swift
+import Test
+import CxxStdlib
+
+func takeCopyable<T: Copyable>(_ x: T) {}
+
+#if TEST1
+func simpleTest() {
+    let s = OwnsNonCopyable()
+    takeCopyable(s) 
+}
+
+#elseif TEST2
+func derived() {
+    let s = DerivedNonCopyable()
+    takeCopyable(s) 
+}
+
+#elseif TEST3
+func annotated() {
+    let s = AnnotatedOwnsNonCopyable()
+    // Annotated has a correct SWIFT_COPYABLE_IF annotation, but OwnsT does not
+    // Since we import OwnsT<NonCopyable> as Copyable (even though it cannot be copy constructible), 
+    // we end up also importing Annotated<OwnsT<NonCopyable>> as Copyable
+    takeCopyable(s)
+}
+
+#elseif TEST4
+func requires() {
+    let s = RequiresOwnsNonCopyable()
+    // Requires makes use of 'requires' correctly, but OwnsT is missing some information
+    // Since we import OwnsT<NonCopyable> as Copyable (even though it cannot be copy constructible), 
+    // we end up also importing Requires<OwnsT<NonCopyable>> as Copyable
+    takeCopyable(s)
+}
+
+#endif
diff --git a/test/Interop/Cxx/class/noncopyable-typechecker.swift b/test/Interop/Cxx/class/noncopyable-typechecker.swift
new file mode 100644
index 0000000000000..8c68bd1381600
--- /dev/null
+++ b/test/Interop/Cxx/class/noncopyable-typechecker.swift
@@ -0,0 +1,131 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -cxx-interoperability-mode=default -typecheck -verify -I %swift_src_root/lib/ClangImporter/SwiftBridging -I %t%{fs-sep}Inputs %t%{fs-sep}test.swift -verify-additional-file %t%{fs-sep}Inputs%{fs-sep}noncopyable.h
+// RUN: %target-swift-frontend -cxx-interoperability-mode=default -Xcc -std=c++20 -verify-additional-prefix cpp20- -D CPP20 -typecheck -verify -I %swift_src_root/lib/ClangImporter/SwiftBridging -I %t%{fs-sep}Inputs %t%{fs-sep}test.swift -verify-additional-file %t%{fs-sep}Inputs%{fs-sep}noncopyable.h
+
+//--- Inputs/module.modulemap
+module Test {
+    header "noncopyable.h"
+    requires cplusplus
+}
+
+//--- Inputs/noncopyable.h
+#include "swift/bridging"
+#include <string>
+
+struct NonCopyable {
+    NonCopyable() = default;
+    NonCopyable(const NonCopyable& other) = delete;
+    NonCopyable(NonCopyable&& other) = default;
+};
+
+template <typename T>
+struct OwnsT {
+    T element;
+    OwnsT() {}
+    OwnsT(const OwnsT &other) : element(other.element) {}
+    OwnsT(OwnsT&& other) {}
+};
+
+using OwnsNonCopyable = OwnsT<NonCopyable>;
+
+template <typename T>
+struct SWIFT_COPYABLE_IF(T) AnnotatedOwnsT {
+    T element;
+    AnnotatedOwnsT() {}
+    AnnotatedOwnsT(const AnnotatedOwnsT &other) : element(other.element) {}
+    AnnotatedOwnsT(AnnotatedOwnsT&& other) {}
+};
+
+using AnnotatedOwnsNonCopyable = AnnotatedOwnsT<NonCopyable>;
+
+template <typename F, typename S>
+struct SWIFT_COPYABLE_IF(F, S) MyPair {
+    F first;
+    S second;
+};
+
+MyPair<int, NonCopyable> p1();
+MyPair<int, NonCopyable*> p2();
+MyPair<int, OwnsNonCopyable> p3();
+MyPair<int, AnnotatedOwnsNonCopyable> p4();
+MyPair<int, MyPair<int, NonCopyable>> p5();
+MyPair<NonCopyable, int> p6();
+
+#if __cplusplus >= 202002L
+template <typename T>
+struct RequiresCopyableT {
+    T element;
+    RequiresCopyableT() {}
+    RequiresCopyableT(const RequiresCopyableT &other) requires std::is_copy_constructible_v<T> : element(other.element) {}
+    RequiresCopyableT(RequiresCopyableT&& other) {}
+};
+
+using NonCopyableRequires = RequiresCopyableT<NonCopyable>;
+using CopyableIfRequires = RequiresCopyableT<MyPair<int, NonCopyable>>;
+
+MyPair<int, NonCopyableRequires> p7();
+
+#endif
+
+template<typename T>
+struct SWIFT_COPYABLE_IF(T) SWIFT_NONCOPYABLE DoubleAnnotation {};
+
+using DoubleAnnotationInt = DoubleAnnotation<int>;
+
+struct SWIFT_NONCOPYABLE NonCopyableNonMovable { // expected-note {{record 'NonCopyableNonMovable' is not automatically available: it must have a copy/move constructor and a destructor; does this type have reference semantics?}}
+    NonCopyableNonMovable() {}
+    NonCopyableNonMovable(const NonCopyableNonMovable& other) {}
+    NonCopyableNonMovable(NonCopyableNonMovable&& other) = delete;
+};
+
+
+//--- test.swift
+import Test
+import CxxStdlib
+
+func takeCopyable<T: Copyable>(_ x: T) {} // expected-note * {{'where T: Copyable' is implicit here}}
+
+func userDefinedTypes() {
+    let nCop = NonCopyable()
+    takeCopyable(nCop) // expected-error {{global function 'takeCopyable' requires that 'NonCopyable' conform to 'Copyable'}}
+
+    let ownsT = OwnsNonCopyable()
+    takeCopyable(ownsT) // no error, OwnsNonCopyable imported as Copyable
+}
+
+func useCopyableIf() {
+    takeCopyable(p1()) // expected-error {{global function 'takeCopyable' requires that 'MyPair<CInt, NonCopyable>' conform to 'Copyable'}}
+    takeCopyable(p2())
+
+    // p3() -> MyPair<int, OwnsNonCopyable> is imported as Copyable and will cause an error during IRGen.
+    // During typecheck we don't produce an error because we're missing an annotation in OwnsT.
+    takeCopyable(p3())
+    // p4() -> (MyPair<int, AnnotatedOwnsNonCopyable>) is imported as NonCopyable because AnnotatedOwnsT is correctly annotated.
+    takeCopyable(p4()) // expected-error {{global function 'takeCopyable' requires that 'MyPair<CInt, AnnotatedOwnsT<NonCopyable>>' conform to 'Copyable'}}
+
+    takeCopyable(p5()) // expected-error {{global function 'takeCopyable' requires that 'MyPair<CInt, MyPair<CInt, NonCopyable>>' conform to 'Copyable'}}
+    takeCopyable(p6()) // expected-error {{global function 'takeCopyable' requires that 'MyPair<NonCopyable, CInt>' conform to 'Copyable'}}
+}
+
+#if CPP20
+func useOfRequires() {
+    let a = NonCopyableRequires()
+    takeCopyable(a) // expected-cpp20-error {{global function 'takeCopyable' requires that 'NonCopyableRequires' (aka 'RequiresCopyableT<NonCopyable>') conform to 'Copyable'}}
+
+    let b = CopyableIfRequires()
+    takeCopyable(b) // expected-cpp20-error {{global function 'takeCopyable' requires that 'CopyableIfRequires' (aka 'RequiresCopyableT<MyPair<CInt, NonCopyable>>') conform to 'Copyable'}}
+
+    takeCopyable(p7()) // expected-cpp20-error {{global function 'takeCopyable' requires that 'MyPair<CInt, RequiresCopyableT<NonCopyable>>' conform to 'Copyable'}}
+}
+#endif
+
+func doubleAnnotation() {
+    let s = DoubleAnnotationInt()
+    takeCopyable(s) // expected-error {{global function 'takeCopyable' requires that 'DoubleAnnotationInt' (aka 'DoubleAnnotation<CInt>') conform to 'Copyable'}}
+}
+
+func missingLifetimeOperation() {
+    let s = NonCopyableNonMovable() // expected-error {{cannot find 'NonCopyableNonMovable' in scope}}
+    takeCopyable(s)
+}
diff --git a/test/Interop/Cxx/class/nonescapable-errors.swift b/test/Interop/Cxx/class/nonescapable-errors.swift
index 12ae97b0b6f88..e8e7e6b6a0329 100644
--- a/test/Interop/Cxx/class/nonescapable-errors.swift
+++ b/test/Interop/Cxx/class/nonescapable-errors.swift
@@ -14,6 +14,7 @@ module Test {
 //--- Inputs/nonescapable.h
 #include "swift/bridging"
 #include <vector>
+#include <optional>
 
 struct SWIFT_NONESCAPABLE View {
     View() : member(nullptr) {}
@@ -27,6 +28,14 @@ struct SWIFT_ESCAPABLE Owner {
     int data;
 };
 
+template<typename T>
+struct SWIFT_ESCAPABLE TemplatedOwner {
+    T data;
+};
+
+using TemplatedIntOwner = TemplatedOwner<int>;
+using TemplatedFloatOwner = TemplatedOwner<float>;
+
 Owner f(int* x [[clang::lifetimebound]]) { 
     return Owner{0};
 }
@@ -35,6 +44,14 @@ Owner f2(int* x [[clang::lifetimebound]], int* y [[clang::lifetimebound]]) {
     return Owner{0};
 }
 
+TemplatedIntOwner f3(int* x [[clang::lifetimebound]]) { 
+    return TemplatedOwner<int>{0};
+}
+
+TemplatedFloatOwner f4(int* x [[clang::lifetimebound]]) { 
+    return TemplatedOwner<float>{0};
+}
+
 View g(int* x) {
     return View(x);
 }
@@ -95,49 +112,111 @@ const View* usedToCrash(const View* p) {
     return p;
 }
 
+struct SWIFT_ESCAPABLE Invalid {
+    View v;
+};
+
+struct SWIFT_NONESCAPABLE NonEscapable {};
+
+template<typename T>
+struct HasAnonUnion {
+    union {
+        int known;
+        T unknown;
+    };
+};
+
+template<typename T>
+struct HasAnonStruct {
+    struct {
+        int known;
+        T unknown;
+    };
+};
+
+template<typename T>
+struct SWIFT_NONESCAPABLE NonEscapableHasAnonUnion {
+    union {
+        int known;
+        T unknown;
+    };
+};
+
+using HasAnonUnionNonEscapable = HasAnonUnion<NonEscapable>;
+using HasAnonStructNonEscapable = HasAnonStruct<NonEscapable>;
+using NonEscapableHasAnonUnionNonEscapable = NonEscapableHasAnonUnion<NonEscapable>;
+using NonEscapableOptional = std::optional<NonEscapable>;
+
 //--- test.swift
 import Test
 import CxxStdlib
 
+// CHECK: error: cannot find type 'Invalid' in scope
+// CHECK: note: escapable record 'Invalid' cannot have non-escapable field 'v'
+// CHECK-NO-LIFETIMES: error: cannot find type 'Invalid' in scope
+// CHECK-NO-LIFETIMES: note: escapable record 'Invalid' cannot have non-escapable field 'v'
+public func importInvalid(_ x: Invalid) {
+}
+
 // CHECK: error: a function with a ~Escapable result needs a parameter to depend on
-// CHECK-NO-LIFETIMES: test.swift:6:32: error: a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'
+// CHECK-NO-LIFETIMES: test.swift:13:32: error: a function cannot return a ~Escapable result
 public func noAnnotations() -> View {
-    // CHECK: nonescapable.h:16:7: warning: the returned type 'Owner' is annotated as escapable; it cannot have lifetime dependencies
-    // CHECK-NO-LIFETIMES: nonescapable.h:16:7: warning: the returned type 'Owner' is annotated as escapable; it cannot have lifetime dependencies
+    // CHECK: nonescapable.h:25:7: warning: the returned type 'Owner' is annotated as escapable; it cannot have lifetime dependencies [#ClangDeclarationImport]
+    // CHECK-NO-LIFETIMES: nonescapable.h:25:7: warning: the returned type 'Owner' is annotated as escapable; it cannot have lifetime dependencies [#ClangDeclarationImport]
     f(nil)
-    // CHECK: nonescapable.h:20:7: warning: the returned type 'Owner' is annotated as escapable; it cannot have lifetime dependencies
-    // CHECK-NO-LIFETIMES: nonescapable.h:20:7: warning: the returned type 'Owner' is annotated as escapable; it cannot have lifetime dependencies
+    // CHECK: nonescapable.h:29:7: warning: the returned type 'Owner' is annotated as escapable; it cannot have lifetime dependencies [#ClangDeclarationImport]
+    // CHECK-NO-LIFETIMES: nonescapable.h:29:7: warning: the returned type 'Owner' is annotated as escapable; it cannot have lifetime dependencies [#ClangDeclarationImport]
     // No duplicate warning for f2:
-    // CHECK-NOT: nonescapable.h:20
+    // CHECK-NOT: nonescapable.h:29
     f2(nil, nil)
-    // CHECK: nonescapable.h:24:6: warning: the returned type 'View' is annotated as non-escapable; its lifetime dependencies must be annotated
-    // CHECK-NO-LIFETIMES: nonescapable.h:24:6: warning: the returned type 'View' is annotated as non-escapable; its lifetime dependencies must be annotated
-    // CHECK-NO-LIFETIMES: nonescapable.h:24:6: error: a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'
+    // CHECK: nonescapable.h:33:19: warning: the returned type 'TemplatedIntOwner' is annotated as escapable; it cannot have lifetime dependencies [#ClangDeclarationImport]
+    // CHECK-NO-LIFETIMES: nonescapable.h:33:19: warning: the returned type 'TemplatedIntOwner' is annotated as escapable; it cannot have lifetime dependencies [#ClangDeclarationImport]
+    // No duplicate warning for f3:
+    // CHECK-NOT: nonescapable.h:33
+    f3(nil)
+    // CHECK: nonescapable.h:37:21: warning: the returned type 'TemplatedFloatOwner' is annotated as escapable; it cannot have lifetime dependencies [#ClangDeclarationImport]
+    // CHECK-NO-LIFETIMES: nonescapable.h:37:21: warning: the returned type 'TemplatedFloatOwner' is annotated as escapable; it cannot have lifetime dependencies [#ClangDeclarationImport]
+    // No duplicate warning for f4:
+    // CHECK-NOT: nonescapable.h:35
+    f4(nil)
+    // CHECK: nonescapable.h:41:6: warning: the returned type 'View' is annotated as non-escapable; its lifetime dependencies must be annotated [#ClangDeclarationImport]
+    // CHECK-NO-LIFETIMES: nonescapable.h:41:6: warning: the returned type 'View' is annotated as non-escapable; its lifetime dependencies must be annotated [#ClangDeclarationImport]
+    // CHECK-NO-LIFETIMES: nonescapable.h:41:6: error: a function cannot return a ~Escapable result
     g(nil)
     h1(nil)
-    // CHECK-NO-LIFETIMES: nonescapable.h:34:21: error: a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'
+    // CHECK-NO-LIFETIMES: nonescapable.h:51:21: error: a function cannot return a ~Escapable result
     h2(nil)
-    // CHECK-NO-LIFETIMES: nonescapable.h:35:21: error: a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'
+    // CHECK-NO-LIFETIMES: nonescapable.h:52:21: error: a function cannot return a ~Escapable result
     h3(nil)
     i1()
-    // CHECK: nonescapable.h:39:39: error: template parameter 'Missing' does not exist
-    // CHECK-NO-LIFETIMES: nonescapable.h:39:39: error: template parameter 'Missing' does not exist
+    // CHECK: nonescapable.h:56:39: error: template parameter 'Missing' does not exist
+    // CHECK-NO-LIFETIMES: nonescapable.h:56:39: error: template parameter 'Missing' does not exist
     i2()
-    // CHECK: nonescapable.h:45:33: error: template parameter 'S' expected to be a type parameter
-    // CHECK-NO-LIFETIMES: nonescapable.h:45:33: error: template parameter 'S' expected to be a type parameter
+    // CHECK: nonescapable.h:62:33: error: template parameter 'S' expected to be a type parameter
+    // CHECK: nonescapable.h:80:41: error: a function with a ~Escapable result needs a parameter to depend on
+    // CHECK: note: '@_lifetime(immortal)' can be used to indicate that values produced
+    // CHECK-NO-LIFETIMES: nonescapable.h:62:33: error: template parameter 'S' expected to be a type parameter
     j1()
-    // CHECK-NO-LIFETIMES: nonescapable.h:63:41: error: a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'
+    // CHECK-NO-LIFETIMES: nonescapable.h:80:41: error: a function cannot return a ~Escapable result
     j2()
-    // CHECK-NO-LIFETIMES: nonescapable.h:64:41: error: a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'
+    // CHECK: nonescapable.h:81:41: error: a function with a ~Escapable result needs a parameter to depend on
+    // CHECK-NO-LIFETIMES: nonescapable.h:81:41: error: a function cannot return a ~Escapable result
+    // CHECK: note: '@_lifetime(immortal)' can be used to indicate that values produced
     j3()
     k1();
-    // CHECK-NO-LIFETIMES: nonescapable.h:70:15: error: a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'
+    // CHECK: nonescapable.h:87:15: error: a function with a ~Escapable result needs a parameter to depend on
+    // CHECK: nonescapable.h:87:15: note: '@_lifetime(immortal)' can be used to indicate that values produced
+    // CHECK-NO-LIFETIMES: nonescapable.h:87:15: error: a function cannot return a ~Escapable result
+
     k2();
-    // CHECK-NO-LIFETIMES: nonescapable.h:71:22: error: a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'
+    // CHECK: nonescapable.h:88:22: error: a function with a ~Escapable result needs a parameter to depend on
+    // CHECK-NO-LIFETIMES: nonescapable.h:88:22: error: a function cannot return a ~Escapable result
+    // CHECK: note: '@_lifetime(immortal)' can be used to indicate that values produced
     k3();
     l1();
-    // CHECK: nonescapable.h:77:12: error: a function with a ~Escapable result needs a parameter to depend on
-    // CHECK-NO-LIFETIMES: nonescapable.h:77:12: error: a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'
+    // CHECK: nonescapable.h:94:12: error: a function with a ~Escapable result needs a parameter to depend on
+    // CHECK: nonescapable.h:94:12: note: '@_lifetime(immortal)' can be used to indicate that values produced by this initializer have no lifetime dependencies
+    // CHECK-NO-LIFETIMES: nonescapable.h:94:12: error: a function cannot return a ~Escapable result
     l2();
     return View()
 }
@@ -153,6 +232,21 @@ public func test3(_ x: inout View) {
     // CHECK-NO-LIFETIMES: note: return type unavailable (cannot import)
     // CHECK-NO-LIFETIMES: pointer to non-escapable type 'View' cannot be imported
 }
+
+public func anonymousUnions() {
+    _ = HasAnonUnionNonEscapable()
+    // CHECK: error: cannot find 'HasAnonUnionNonEscapable' in scope
+    // CHECK-NO-LIFETIMES: error: cannot find 'HasAnonUnionNonEscapable' in scope
+    _ = HasAnonStructNonEscapable()
+    // CHECK: error: cannot find 'HasAnonStructNonEscapable' in scope
+    // CHECK-NO-LIFETIMES: error: cannot find 'HasAnonStructNonEscapable' in scope
+    _ = NonEscapableHasAnonUnionNonEscapable()
+    _ = NonEscapableOptional()
+    // CHECK: error: cannot infer the lifetime dependence scope on an initializer with a ~Escapable parameter, specify '@_lifetime(borrow {{.*}})' or '@_lifetime(copy {{.*}})'
+    // CHECK-NO-LIFETIMES: error: an initializer cannot return a ~Escapable result
+    // CHECK-NO-LIFETIMES: error: an initializer cannot return a ~Escapable result
+}
+
     // CHECK-NOT: error
     // CHECK-NOT: warning
     // CHECK-NO-LIFETIMES-NOT: error
diff --git a/test/Interop/Cxx/class/nonescapable-lifetimebound.swift b/test/Interop/Cxx/class/nonescapable-lifetimebound.swift
index e2cea876448b0..e15f9bfa48779 100644
--- a/test/Interop/Cxx/class/nonescapable-lifetimebound.swift
+++ b/test/Interop/Cxx/class/nonescapable-lifetimebound.swift
@@ -73,7 +73,7 @@ View getViewFromEither(View view1 [[clang::lifetimebound]], View view2 [[clang::
 struct SWIFT_NONESCAPABLE TestAnnotationTranslation {
     TestAnnotationTranslation() : member(nullptr) {}
     TestAnnotationTranslation(const int *p [[clang::lifetimebound]]) : member(p) {}
-    TestAnnotationTranslation(const TestAnnotationTranslation& [[clang::lifetimebound]]) = default;
+    TestAnnotationTranslation(const TestAnnotationTranslation& other [[clang::lifetimebound]]) = default;
 private:
     const int *member;
 };
@@ -109,10 +109,67 @@ struct SWIFT_NONESCAPABLE AggregateView {
     const int *member;
 };
 
+namespace NS {
+    View getView(const Owner& owner [[clang::lifetimebound]]) {
+        return View(&owner.data);
+    }
+}
+
+struct SWIFT_NONCOPYABLE SWIFT_NONESCAPABLE MoveOnly {
+    MoveOnly();
+    MoveOnly(const MoveOnly& other) = delete;
+    MoveOnly& operator=(const MoveOnly&) = delete;
+    MoveOnly(MoveOnly&& other) = default;
+    MoveOnly& operator=(MoveOnly&& other) = default;
+    ~MoveOnly();
+
+private:
+    int *i;
+};
+
+MoveOnly moveOnlyId(const MoveOnly& p [[clang::lifetimebound]]);
+
+namespace rdar153081347 {
+namespace Detail {
+template<typename T>
+class SWIFT_NONESCAPABLE Span {
+public:
+   constexpr Span() = default;
+   constexpr Span(T* p [[clang::lifetimebound]], unsigned long s) : m_ptr(p), m_size(s) {}
+
+   template<unsigned long size>
+   constexpr Span(T (&a)[size]) : m_ptr(a), m_size(size) {}
+protected:
+  T* m_ptr { nullptr };
+  unsigned long m_size { 0 };
+};
+} // namespace Detail
+
+template <typename T>
+class SWIFT_NONESCAPABLE Span : public Detail::Span<T> {
+public:
+  using Detail::Span<T>::Span;
+
+  constexpr Span() = default;
+
+  constexpr T const* data() const { return this->m_ptr; }
+  constexpr T* data() { return this->m_ptr; }
+
+  constexpr unsigned long size() const { return this->m_size; }
+
+};
+
+template<typename T>
+using ReadonlySpan = Span<T const>;
+
+using ReadonlyBytes = ReadonlySpan<unsigned char>;
+using Bytes = Span<unsigned char>;
+} // namespace rdar153081347
+
 // CHECK: sil [clang makeOwner] {{.*}}: $@convention(c) () -> Owner
-// CHECK: sil [clang getView] {{.*}} : $@convention(c) (@in_guaranteed Owner) -> @lifetime(borrow 0) @owned View
-// CHECK: sil [clang getViewFromFirst] {{.*}} : $@convention(c) (@in_guaranteed Owner, @in_guaranteed Owner) -> @lifetime(borrow 0) @owned View
-// CHECK: sil [clang getViewFromEither] {{.*}} : $@convention(c) (@in_guaranteed Owner, @in_guaranteed Owner) -> @lifetime(borrow 0, borrow 1) @owned View
+// CHECK: sil [clang getView] {{.*}} : $@convention(c) (@in_guaranteed Owner) -> @lifetime(borrow address 0) @owned View
+// CHECK: sil [clang getViewFromFirst] {{.*}} : $@convention(c) (@in_guaranteed Owner, @in_guaranteed Owner) -> @lifetime(borrow address 0) @owned View
+// CHECK: sil [clang getViewFromEither] {{.*}} : $@convention(c) (@in_guaranteed Owner, @in_guaranteed Owner) -> @lifetime(borrow address 0, borrow address 1) @owned View
 // CHECK: sil [clang Owner.handOutView] {{.*}} : $@convention(cxx_method) (@in_guaranteed Owner) -> @lifetime(borrow 0) @owned View
 // CHECK: sil [clang Owner.handOutView2] {{.*}} : $@convention(cxx_method) (View, @in_guaranteed Owner) -> @lifetime(borrow 1) @owned View
 // CHECK: sil [clang getViewFromEither] {{.*}} : $@convention(c) (View, View) -> @lifetime(copy 0, copy 1) @owned View
@@ -120,9 +177,11 @@ struct SWIFT_NONESCAPABLE AggregateView {
 // CHECK: sil [clang OtherView.init] {{.*}} : $@convention(c) (View) -> @lifetime(copy 0) @out OtherView
 // CHECK: sil [clang returnsImmortal] {{.*}} : $@convention(c) () -> @lifetime(immortal) @owned View
 // CHECK: sil [clang copyView] {{.*}} : $@convention(c) (View, @lifetime(copy 0) @inout View) -> ()
-// CHECK: sil [clang getCaptureView] {{.*}} : $@convention(c) (@in_guaranteed Owner) -> @lifetime(borrow 0) @owned CaptureView
+// CHECK: sil [clang getCaptureView] {{.*}} : $@convention(c) (@in_guaranteed Owner) -> @lifetime(borrow address 0) @owned CaptureView
 // CHECK: sil [clang CaptureView.captureView] {{.*}} : $@convention(cxx_method) (View, @lifetime(copy 0) @inout CaptureView) -> ()
 // CHECK: sil [clang CaptureView.handOut] {{.*}} : $@convention(cxx_method) (@lifetime(copy 1) @inout View, @in_guaranteed CaptureView) -> ()
+// CHECK: sil [clang NS.getView] {{.*}} : $@convention(c) (@in_guaranteed Owner) -> @lifetime(borrow address 0) @owned View
+// CHECK: sil [clang moveOnlyId] {{.*}} : $@convention(c) (@in_guaranteed MoveOnly) -> @lifetime(borrow {{.*}}0) @out MoveOnly
 
 //--- test.swift
 
@@ -144,8 +203,15 @@ public func test() {
     var cv = getCaptureView(o)
     cv.captureView(v1)
     cv.handOut(&v1)
+    var _ = NS.getView(o)
 }
 
 public func test2(_ x: AggregateView) {
     let _ = AggregateView(member: x.member)
 }
+
+func canImportMoveOnlyNonEscapable(_ x: borrowing MoveOnly) {
+    let _ = moveOnlyId(x);
+}
+
+func testInheritedCtors(_ s: rdar153081347.Bytes) {}
diff --git a/test/Interop/Cxx/class/print-simple-structs.swift b/test/Interop/Cxx/class/print-simple-structs.swift
new file mode 100644
index 0000000000000..ee8e3209e0add
--- /dev/null
+++ b/test/Interop/Cxx/class/print-simple-structs.swift
@@ -0,0 +1,45 @@
+// RUN: %target-run-simple-swift(-cxx-interoperability-mode=default -I %S/Inputs) | %FileCheck %s
+
+// REQUIRES: executable_test
+
+import SimpleStructs
+
+func printCxxStructPrivateFields() {
+    let s = HasPrivateFieldsOnly(1, 2)
+    print(s)
+}
+
+func printCxxStructPublicFields() {
+    let s = HasPublicFieldsOnly(1, 2)
+    print(s)
+}
+
+func printCxxStructPrivatePublicProtectedFields() {
+    let s = HasPrivatePublicProtectedFields(1, 2, 3, 4, 5, 6)
+    print(s)
+}
+
+func printCxxStructNested() {
+    let s = Outer()
+    print(s)
+}
+
+func printCxxStructWithAnonType() {
+    let s = HasAnonymousType(1, 2, 3)
+    print(s)
+}
+
+printCxxStructPrivateFields() 
+// CHECK: HasPrivateFieldsOnly()
+
+printCxxStructPublicFields()
+// CHECK: HasPublicFieldsOnly(publ1: 1, publ2: 2)
+
+printCxxStructPrivatePublicProtectedFields()
+// CHECK: HasPrivatePublicProtectedFields(publ1: 2, publ2: 6)
+
+printCxxStructNested()
+// CHECK: Outer(publStruct: {{.*}}.HasPrivatePublicProtectedFields(publ1: 8, publ2: 12))
+
+printCxxStructWithAnonType()
+// CHECK: HasAnonymousType(c: 3)
diff --git a/test/Interop/Cxx/class/protocol-conformance-irgen.swift b/test/Interop/Cxx/class/protocol-conformance-irgen.swift
index d5dbbe435add5..aa464726f7c97 100644
--- a/test/Interop/Cxx/class/protocol-conformance-irgen.swift
+++ b/test/Interop/Cxx/class/protocol-conformance-irgen.swift
@@ -7,7 +7,7 @@ protocol HasReturn42 {
 }
 
 
-// CHECK: define {{.*}}i32 @"$sSo18ConformsToProtocolV4main11HasReturn42A2cDP8return42s5Int32VyFTW"(ptr nocapture swiftself dereferenceable(1) %{{.*}}, ptr %{{.*}}, ptr %{{.*}})
+// CHECK: define {{.*}}i32 @"$sSo18ConformsToProtocolV4main11HasReturn42A2cDP8return42s5Int32VyFTW"(ptr{{( nocapture)?}} swiftself{{( captures\(none\))?}} dereferenceable(1) %{{.*}}, ptr %{{.*}}, ptr %{{.*}})
 // CHECK: [[OUT:%.*]] = call i32 @{{_ZN18ConformsToProtocol8return42Ev|"\?return42@ConformsToProtocol@@QEAAHXZ"}}(ptr
 // CHECK: ret i32 [[OUT]]
 
diff --git a/test/Interop/Cxx/class/protocol-conformance-typechecker.swift b/test/Interop/Cxx/class/protocol-conformance-typechecker.swift
index c12f77f26af85..25f6bedb1b80d 100644
--- a/test/Interop/Cxx/class/protocol-conformance-typechecker.swift
+++ b/test/Interop/Cxx/class/protocol-conformance-typechecker.swift
@@ -1,9 +1,9 @@
 // Tests that a C++ class can conform to a Swift protocol.
 
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -enable-experimental-cxx-interop
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -D VIRTUAL_METHODS -cxx-interoperability-mode=swift-5.9
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -D VIRTUAL_METHODS -cxx-interoperability-mode=swift-6
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -D VIRTUAL_METHODS -cxx-interoperability-mode=upcoming-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -enable-experimental-cxx-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -D VIRTUAL_METHODS -cxx-interoperability-mode=swift-5.9
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -D VIRTUAL_METHODS -cxx-interoperability-mode=swift-6
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -D VIRTUAL_METHODS -cxx-interoperability-mode=upcoming-swift
 
 import ProtocolConformance
 
diff --git a/test/Interop/Cxx/class/returns-large-class-irgen.swift b/test/Interop/Cxx/class/returns-large-class-irgen.swift
index d9e6f3af56c7a..32dac01116335 100644
--- a/test/Interop/Cxx/class/returns-large-class-irgen.swift
+++ b/test/Interop/Cxx/class/returns-large-class-irgen.swift
@@ -14,7 +14,7 @@ func foo() -> LargeClass {
 
 foo()
 
-// CHECK: call swiftcc void @"$s4main3fooSo10LargeClassVyF"(ptr noalias nocapture sret(%TSo10LargeClassV) %{{.*}})
+// CHECK: call swiftcc void @"$s4main3fooSo10LargeClassVyF"(ptr noalias{{( nocapture)?}} sret(%TSo10LargeClassV){{( captures\(none\))?}} %{{.*}})
 
 // The C++ function:
 // CHECK: define{{( dso_local)?}} void @{{_Z21funcReturnsLargeClassv|"\?funcReturnsLargeClass@@YA\?AULargeClass@@XZ"}}({{%struct.LargeClass\*|ptr}}{{.*}} sret(%struct.LargeClass){{( align .*)?}} %{{.*}})
diff --git a/test/Interop/Cxx/class/returns-unavailable-class.swift b/test/Interop/Cxx/class/returns-unavailable-class.swift
index 058efe4370d59..9ac44bf7b8d57 100644
--- a/test/Interop/Cxx/class/returns-unavailable-class.swift
+++ b/test/Interop/Cxx/class/returns-unavailable-class.swift
@@ -2,7 +2,7 @@
 // RUN: split-file %s %t
 // RUN: %target-swift-ide-test -print-module -module-to-print=CxxModule -I %t/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
 
-// RUN: %target-swift-frontend -typecheck -verify -I %t/Inputs -enable-experimental-cxx-interop %t/test.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t/Inputs -enable-experimental-cxx-interop %t/test.swift
 
 //--- Inputs/module.modulemap
 module CxxTypes {
diff --git a/test/Interop/Cxx/class/safe-interop-mode-darwin.swift b/test/Interop/Cxx/class/safe-interop-mode-darwin.swift
new file mode 100644
index 0000000000000..6f7de581e863c
--- /dev/null
+++ b/test/Interop/Cxx/class/safe-interop-mode-darwin.swift
@@ -0,0 +1,34 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -typecheck -verify -I %swift_src_root/lib/ClangImporter/SwiftBridging -Xcc -std=c++20 -I %t/Inputs  %t/test.swift -strict-memory-safety -enable-experimental-feature LifetimeDependence -cxx-interoperability-mode=default -diagnostic-style llvm 2>&1
+
+// REQUIRES: objc_interop
+// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: OS=macosx
+
+//--- Inputs/module.modulemap
+module Test {
+    header "nonescapable.h"
+    requires cplusplus
+}
+
+//--- Inputs/nonescapable.h
+#pragma once
+
+#include <simd/simd.h>
+#include <vector>
+
+using VecOfSimd = std::vector<simd::float3>;
+using MySimd = simd::float3;
+
+//--- test.swift
+import Test
+import CxxStdlib
+
+func simdConsideredSafe(x : MySimd) {
+    let _ = x
+}
+
+func simdVecConsideredSafe(x : VecOfSimd) {
+    let _ = x
+}
\ No newline at end of file
diff --git a/test/Interop/Cxx/class/safe-interop-mode.swift b/test/Interop/Cxx/class/safe-interop-mode.swift
index fab3578028017..2b9187a7a263e 100644
--- a/test/Interop/Cxx/class/safe-interop-mode.swift
+++ b/test/Interop/Cxx/class/safe-interop-mode.swift
@@ -1,7 +1,7 @@
 
 // RUN: rm -rf %t
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend -typecheck -verify -I %swift_src_root/lib/ClangImporter/SwiftBridging -Xcc -std=c++20 -I %t/Inputs  %t/test.swift -strict-memory-safety -enable-experimental-feature LifetimeDependence -cxx-interoperability-mode=default -diagnostic-style llvm 2>&1
+// RUN: %target-swift-frontend -typecheck -verify -I %swift_src_root/lib/ClangImporter/SwiftBridging -Xcc -iapinotes-modules -Xcc %swift_src_root/stdlib/public/Cxx/std -Xcc -std=c++20 -I %t/Inputs  %t/test.swift -strict-memory-safety -enable-experimental-feature LifetimeDependence -cxx-interoperability-mode=default -diagnostic-style llvm 2>&1
 
 // REQUIRES: objc_interop
 // REQUIRES: swift_feature_LifetimeDependence
@@ -63,6 +63,21 @@ View safeFunc(View v1 [[clang::noescape]], View v2 [[clang::lifetimebound]]);
 // Second non-escapable type is not annotated in any way.
 void unsafeFunc(View v1 [[clang::noescape]], View v2);
 
+class SharedObject {
+private:
+  int *p;
+} SWIFT_SHARED_REFERENCE(retainSharedObject, releaseSharedObject);
+
+inline void retainSharedObject(SharedObject *) {}
+inline void releaseSharedObject(SharedObject *) {}
+
+struct DerivedFromSharedObject : SharedObject {};
+
+struct OwnedData {
+  SpanOfInt getView() const [[clang::lifetimebound]];
+  void takeSharedObject(SharedObject *) const;
+};
+
 //--- test.swift
 
 import Test
@@ -119,6 +134,7 @@ func useUnsafeTuple(x: UnsafeTuple) {
 func useCppSpan(x: SpanOfInt) {
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
   _ = x // expected-note{{reference to parameter 'x' involves unsafe type}}
+  _ = x.size()
 }
 
 func useCppSpan2(x: SpanOfIntAlias) {
@@ -126,6 +142,12 @@ func useCppSpan2(x: SpanOfIntAlias) {
   _ = x // expected-note{{reference to parameter 'x' involves unsafe type}}
 }
 
+func useCppSpan3() -> SpanOfInt {
+  let x = OwnedData()
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
+  return x.getView() // expected-note {{reference to instance method 'getView()' involves unsafe type 'SpanOfInt'}}
+}
+
 func useSafeLifetimeAnnotated(v: View) {
     let _ = safeFunc(v, v)
 }
@@ -134,3 +156,14 @@ func useUnsafeLifetimeAnnotated(v: View) {
     // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
     unsafeFunc(v, v) // expected-note{{reference to unsafe global function 'unsafeFunc'}}
 }
+
+@available(SwiftStdlib 5.8, *)
+func useSharedReference(frt: SharedObject, x: OwnedData) {
+  let _ = frt
+  x.takeSharedObject(frt)
+}
+
+@available(SwiftStdlib 5.8, *)
+func useSharedReference(frt: DerivedFromSharedObject) {
+  let _ = frt
+}
diff --git a/test/Interop/Cxx/class/sendable-typechecker.swift b/test/Interop/Cxx/class/sendable-typechecker.swift
index f4de5f48483a4..9a3097e4fc199 100644
--- a/test/Interop/Cxx/class/sendable-typechecker.swift
+++ b/test/Interop/Cxx/class/sendable-typechecker.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -swift-version 6 -cxx-interoperability-mode=upcoming-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -swift-version 6 -cxx-interoperability-mode=upcoming-swift
 
 import Sendable // expected-warning {{add '@preconcurrency' to treat 'Sendable'-related errors from module 'Sendable' as warnings}}
 
diff --git a/test/Interop/Cxx/class/type-classification-non-trivial-irgen.swift b/test/Interop/Cxx/class/type-classification-non-trivial-irgen.swift
index ad62ecb3174d5..85037614603df 100644
--- a/test/Interop/Cxx/class/type-classification-non-trivial-irgen.swift
+++ b/test/Interop/Cxx/class/type-classification-non-trivial-irgen.swift
@@ -13,8 +13,8 @@ import TypeClassification
 // CHECK-LABEL: define {{.*}}i1 @"$s4main37testStructWithCopyConstructorAndValueSbyF"
 // CHECK: [[OBJ:%.*]] = alloca %TSo33StructWithCopyConstructorAndValueV
 // CHECK: call {{.*}}@{{_ZN33StructWithCopyConstructorAndValueC(1|2)Ei|"\?\?0StructWithCopyConstructorAndValue@@QEAA@H@Z"}}(ptr {{(noalias )?}}[[OBJ]], i32 42)
-// CHECK: [[OBJ_VAL:%.*]] = getelementptr inbounds %TSo33StructWithCopyConstructorAndValueV, ptr [[OBJ]], i32 0, i32 0
-// CHECK: [[I_VAL:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[OBJ_VAL]], i32 0, i32 0
+// CHECK: [[OBJ_VAL:%.*]] = getelementptr inbounds{{.*}} %TSo33StructWithCopyConstructorAndValueV, ptr [[OBJ]], i32 0, i32 0
+// CHECK: [[I_VAL:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[OBJ_VAL]], i32 0, i32 0
 // CHECK: [[I_VAL_VAL:%.*]] = load i32, ptr [[OBJ_VAL]]
 // CHECK: [[OUT:%.*]] = icmp eq i32 [[I_VAL_VAL]], 42
 // CHECK: ret i1 [[OUT]]
@@ -27,10 +27,11 @@ public func testStructWithCopyConstructorAndValue() -> Bool {
 // CHECK: [[MEMBER:%.*]] = alloca %TSo33StructWithCopyConstructorAndValueV
 // CHECK: [[OBJ:%.*]] = alloca %TSo42StructWithSubobjectCopyConstructorAndValueV
 // CHECK: alloca %TSo33StructWithCopyConstructorAndValueV
-// CHECK: [[TMP:%.*]] = alloca %TSo33StructWithCopyConstructorAndValueV
 // CHECK: call {{.*}}@{{_ZN33StructWithCopyConstructorAndValueC(1|2)Ei|"\?\?0StructWithCopyConstructorAndValue@@QEAA@H@Z"}}(ptr {{(noalias )?}}[[MEMBER]], i32 42)
-// CHECK: [[TEMP_MEMBER:%.*]] = getelementptr inbounds %TSo33StructWithCopyConstructorAndValueV, ptr [[TMP]], i32 0, i32 0
-// CHECK: [[TEMP_MEMBER_VALUE:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[TEMP_MEMBER]], i32 0, i32 0
+// CHECK: getelementptr inbounds{{.*}} %TSo42StructWithSubobjectCopyConstructorAndValueV, ptr [[OBJ]]
+// CHECK: [[M1:%.*]] = getelementptr inbounds{{.*}} %TSo42StructWithSubobjectCopyConstructorAndValueV, ptr [[OBJ]], i32 0, i32 0
+// CHECK: [[TEMP_MEMBER:%.*]] = getelementptr inbounds{{.*}} %TSo33StructWithCopyConstructorAndValueV, ptr [[M1]], i32 0, i32 0
+// CHECK: [[TEMP_MEMBER_VALUE:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[TEMP_MEMBER]], i32 0, i32 0
 // CHECK: [[LHS:%.*]] = load i32, ptr [[TEMP_MEMBER_VALUE]]
 // CHECK: [[OUT:%.*]] = icmp eq i32 [[LHS]], 42
 // CHECK: ret i1 [[OUT]]
@@ -44,12 +45,12 @@ public func testStructWithSubobjectCopyConstructorAndValue() -> Bool {
 // CHECK: [[MEMBER:%.*]] = alloca %TSo33StructWithCopyConstructorAndValueV
 // CHECK: [[OBJ:%.*]] = alloca %TSo037StructWithCopyConstructorAndSubobjectcdE5ValueV
 // CHECK: [[TEMP:%.*]] = alloca %TSo33StructWithCopyConstructorAndValueV
-// CHECK: [[TEMP2:%.*]] = alloca %TSo33StructWithCopyConstructorAndValueV
 // CHECK: call {{.*}}@{{_ZN33StructWithCopyConstructorAndValueC(1|2)Ei|"\?\?0StructWithCopyConstructorAndValue@@QEAA@H@Z"}}(ptr {{(noalias )?}}[[MEMBER]], i32 42)
 // CHECK: call {{.*}}@{{_ZN33StructWithCopyConstructorAndValueC(1|2)ERKS_|"\?\?0StructWithCopyConstructorAndValue@@QEAA@AEBU0@@Z"}}(ptr [[TEMP]], ptr [[MEMBER]])
 // CHECK: call {{.*}}@{{_ZN60StructWithCopyConstructorAndSubobjectCopyConstructorAndValueC(1|2)E33StructWithCopyConstructorAndValue|"\?\?0StructWithCopyConstructorAndSubobjectCopyConstructorAndValue@@QEAA@UStructWithCopyConstructorAndValue@@@Z"}}(ptr {{(noalias )?}}[[OBJ]], ptr [[TEMP]])
-// CHECK: [[TEMP_MEMBER:%.*]] = getelementptr inbounds %TSo33StructWithCopyConstructorAndValueV, ptr [[TEMP2]], i32 0, i32 0
-// CHECK: [[TEMP_MEMBER_VAL:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[TEMP_MEMBER]], i32 0, i32 0
+// CHECK: [[M1:%.*]] = getelementptr inbounds{{.*}} %TSo037StructWithCopyConstructorAndSubobjectcdE5ValueV, ptr [[OBJ]], i32 0, i32 0
+// CHECK: [[TEMP_MEMBER:%.*]] = getelementptr inbounds{{.*}} %TSo33StructWithCopyConstructorAndValueV, ptr [[M1]], i32 0, i32 0
+// CHECK: [[TEMP_MEMBER_VAL:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[TEMP_MEMBER]], i32 0, i32 0
 // CHECK: [[LHS:%.*]] = load i32, ptr [[TEMP_MEMBER_VAL]]
 // CHECK: [[OUT:%.*]] = icmp eq i32 [[LHS]], 42
 // CHECK: ret i1 [[OUT]]
@@ -63,8 +64,8 @@ public func testStructWithCopyConstructorAndSubobjectCopyConstructorAndValue()
 }
 
 // CHECK-LABEL: define {{.*}}i1 @"$s4main4test3objSbSo33StructWithCopyConstructorAndValueV_tF"(ptr noalias dereferenceable(4) %0)
-// CHECK: [[VAL:%.*]] = getelementptr inbounds %TSo33StructWithCopyConstructorAndValueV, ptr %0, i32 0, i32 0
-// CHECK: [[VAL_VAL:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[VAL]], i32 0, i32 0
+// CHECK: [[VAL:%.*]] = getelementptr inbounds{{.*}} %TSo33StructWithCopyConstructorAndValueV, ptr %0, i32 0, i32 0
+// CHECK: [[VAL_VAL:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[VAL]], i32 0, i32 0
 // CHECK: [[LHS:%.*]] = load i32, ptr [[VAL_VAL]]
 // CHECK: [[OUT:%.*]] = icmp eq i32 [[LHS]], 42
 // CHECK: ret i1 [[OUT]]
@@ -73,10 +74,9 @@ public func test(obj: StructWithCopyConstructorAndValue) -> Bool {
 }
 
 // CHECK-LABEL: define {{.*}}i1 @"$s4main4test3objSbSo42StructWithSubobjectCopyConstructorAndValueV_tF"(ptr noalias dereferenceable(4) %0)
-// CHECK: [[TMP:%.*]] = alloca %TSo33StructWithCopyConstructorAndValueV
-// CHECK: [[MEMBER:%.*]] = getelementptr inbounds %TSo42StructWithSubobjectCopyConstructorAndValueV, ptr %0, i32 0, i32 0
-// CHECK: [[VAL:%.*]] = getelementptr inbounds %TSo33StructWithCopyConstructorAndValueV, ptr [[TMP]], i32 0, i32 0
-// CHECK: [[VAL_VAL:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[VAL]], i32 0, i32 0
+// CHECK: [[MEMBER:%.*]] = getelementptr inbounds{{.*}} %TSo42StructWithSubobjectCopyConstructorAndValueV, ptr %0, i32 0, i32 0
+// CHECK: [[VAL:%.*]] = getelementptr inbounds{{.*}} %TSo33StructWithCopyConstructorAndValueV, ptr [[MEMBER]], i32 0, i32 0
+// CHECK: [[VAL_VAL:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[VAL]], i32 0, i32 0
 // CHECK: [[LHS:%.*]] = load i32, ptr [[VAL_VAL]]
 // CHECK: [[OUT:%.*]] = icmp eq i32 [[LHS]], 42
 // CHECK: ret i1 [[OUT]]
@@ -85,9 +85,9 @@ public func test(obj: StructWithSubobjectCopyConstructorAndValue) -> Bool {
 }
 
 // CHECK-LABEL: define {{.*}}i1 @"$s4main4test3objSbSo037StructWithCopyConstructorAndSubobjectfgH5ValueV_tF"(ptr noalias dereferenceable(4) %0)
-// CHECK:[[TEMP:%.*]] = alloca %TSo33StructWithCopyConstructorAndValueV
-// CHECK:[[VAL:%.*]] = getelementptr inbounds %TSo33StructWithCopyConstructorAndValueV, ptr [[TEMP]], i32 0, i32 0
-// CHECK:[[VAL_VAL:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[VAL]], i32 0, i32 0
+// CHECK:[[TEMP:%.*]] = getelementptr inbounds{{.*}} %TSo037StructWithCopyConstructorAndSubobjectcdE5ValueV, ptr %0, i32 0, i32 0
+// CHECK:[[VAL:%.*]] = getelementptr inbounds{{.*}} %TSo33StructWithCopyConstructorAndValueV, ptr [[TEMP]], i32 0, i32 0
+// CHECK:[[VAL_VAL:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[VAL]], i32 0, i32 0
 // CHECK:[[LHS:%.*]] = load i32, ptr [[VAL_VAL]]
 // CHECK:[[OUT:%.*]] = icmp eq i32 [[LHS]], 42
 // CHECK:ret i1 [[OUT]]
diff --git a/test/Interop/Cxx/class/type-classification-typechecker.swift b/test/Interop/Cxx/class/type-classification-typechecker.swift
index 017e6131d918d..e5e34e5dd3472 100644
--- a/test/Interop/Cxx/class/type-classification-typechecker.swift
+++ b/test/Interop/Cxx/class/type-classification-typechecker.swift
@@ -1,6 +1,6 @@
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=swift-5.9
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=swift-6
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=swift-5.9
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=swift-6
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
 
 import TypeClassification
 
diff --git a/test/Interop/Cxx/class/zero-sized-field.swift b/test/Interop/Cxx/class/zero-sized-field.swift
index ae842b5f8e8e4..04403422e4e2b 100644
--- a/test/Interop/Cxx/class/zero-sized-field.swift
+++ b/test/Interop/Cxx/class/zero-sized-field.swift
@@ -1,4 +1,5 @@
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -enable-experimental-cxx-interop -Xcc -std=c++20)
+// RUN: %empty-directory(%t/index)
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -enable-experimental-cxx-interop -Xcc -std=c++20 -Xfrontend -index-store-path -Xfrontend %t/index)
 //
 // REQUIRES: executable_test
 
@@ -15,7 +16,7 @@ FieldsTestSuite.test("Zero sized field") {
   s.set_c(7)
   takeTypeWithZeroSizedMember(s)
   let s2 = s
-  let myInt : Empty.type = 6
+  let _ : Empty.type = 6
   expectEqual(s.a, 5)
   expectEqual(s.a, s.get_a())
   expectEqual(s2.c, 7)
@@ -24,4 +25,72 @@ FieldsTestSuite.test("Zero sized field") {
   expectEqual(s.b.getNum(), 42)
 }
 
+FieldsTestSuite.test("Optional field padding reused") {
+  var s = ReuseOptionalFieldPadding()
+  let opt = s.getOptional()
+  expectEqual(Int(opt.pointee), 2)
+  s.c = 5
+  expectEqual(Int(s.offset()),  MemoryLayout<ReuseOptionalFieldPadding>.offset(of: \.c)!)
+  expectEqual(s.c, 5)
+  expectEqual(s.get_c(), 5)
+  s.set_c(6)
+  expectEqual(s.c, 6)
+  expectEqual(s.get_c(), 6)
+  let s2 = s
+  expectEqual(s2.c, 6)
+  expectEqual(s2.get_c(), 6)
+}
+
+FieldsTestSuite.test("Typedef'd optional field padding reused") {
+  var s = ReuseOptionalFieldPaddingWithTypedef()
+  s.c = 5
+  expectEqual(Int(s.offset()),  MemoryLayout<ReuseOptionalFieldPadding>.offset(of: \.c)!)
+  expectEqual(s.c, 5)
+  expectEqual(s.get_c(), 5)
+  s.set_c(6)
+  expectEqual(s.c, 6)
+  expectEqual(s.get_c(), 6)
+  let s2 = s
+  expectEqual(s2.c, 6)
+  expectEqual(s2.get_c(), 6)
+}
+
+FieldsTestSuite.test("Non-standard-layout field padding reused") {
+  var s = ReuseNonStandardLayoutFieldPadding()
+  s.c = 5
+  expectEqual(Int(s.offset()),  MemoryLayout<ReuseNonStandardLayoutFieldPadding>.offset(of: \.c)!)
+  expectEqual(s.c, 5)
+  expectEqual(s.get_c(), 5)
+  s.set_c(6)
+  expectEqual(s.c, 6)
+  expectEqual(s.get_c(), 6)
+  let s2 = s
+  expectEqual(s2.c, 6)
+  expectEqual(s2.get_c(), 6)
+}
+
+FieldsTestSuite.test("Non-standard-layout field padding in templated class reused") {
+  var s = ReuseDependentFieldPaddingInt()
+  s.c = 5
+  expectEqual(Int(s.offset()),  MemoryLayout<ReuseDependentFieldPaddingInt>.offset(of: \.c)!)
+  expectEqual(s.c, 5)
+  expectEqual(s.get_c(), 5)
+  s.set_c(6)
+  expectEqual(s.c, 6)
+  expectEqual(s.get_c(), 6)
+  let s2 = s
+  expectEqual(s2.c, 6)
+  expectEqual(s2.get_c(), 6)
+}
+
+FieldsTestSuite.test("Last field is no unique address") {
+  var s = LastFieldNoUniqueAddress()
+
+  s.c = 5
+  expectEqual(s.c, 5)
+
+  s.c = 6
+  expectEqual(s.c, 6)
+}
+
 runAllTests()
diff --git a/test/Interop/Cxx/enum/Inputs/anonymous-with-swift-name.h b/test/Interop/Cxx/enum/Inputs/anonymous-with-swift-name.h
index bcce2c6d0e1d3..24f9cea3f4070 100644
--- a/test/Interop/Cxx/enum/Inputs/anonymous-with-swift-name.h
+++ b/test/Interop/Cxx/enum/Inputs/anonymous-with-swift-name.h
@@ -1,17 +1,8 @@
 #ifndef TEST_INTEROP_CXX_ENUM_INPUTS_ANONYMOUS_WITH_SWIFT_NAME_H
 #define TEST_INTEROP_CXX_ENUM_INPUTS_ANONYMOUS_WITH_SWIFT_NAME_H
 
-#define SOME_OPTIONS(_type, _name) __attribute__((availability(swift, unavailable))) _type _name; enum __attribute__((flag_enum,enum_extensibility(open))) : _name
 #define CF_OPTIONS(_type, _name) __attribute__((availability(swift, unavailable))) _type _name; enum : _name
 
-typedef SOME_OPTIONS(unsigned, SOColorMask) {
-    kSOColorMaskRed = (1 << 1),
-    kSOColorMaskGreen = (1 << 2),
-    kSOColorMaskBlue = (1 << 3),
-    kSOColorMaskAll = ~0U
-};
-
-
 typedef CF_OPTIONS(unsigned, CFColorMask) {
   kCFColorMaskRed = (1 << 1),
   kCFColorMaskGreen = (1 << 2),
@@ -19,20 +10,19 @@ typedef CF_OPTIONS(unsigned, CFColorMask) {
   kCFColorMaskAll = ~0U
 };
 
-inline SOColorMask useSOColorMask(SOColorMask mask) { return mask; }
 inline CFColorMask useCFColorMask(CFColorMask mask) { return mask; }
 
 struct ParentStruct { };
 
 inline CFColorMask renameCFColorMask(ParentStruct parent)
     __attribute__((swift_name("ParentStruct.childFn(self:)")))
-{ return kSOColorMaskRed; }
+{ return kCFColorMaskRed; }
 
 inline CFColorMask getCFColorMask(ParentStruct parent)
     __attribute__((swift_name("getter:ParentStruct.colorProp(self:)")))
-{ return kSOColorMaskRed; }
+{ return kCFColorMaskRed; }
 
-inline void getCFColorMask(ParentStruct parent, CFColorMask newValue)
+inline void setCFColorMask(ParentStruct parent, CFColorMask newValue)
     __attribute__((swift_name("setter:ParentStruct.colorProp(self:newValue:)")))
 { }
 
@@ -52,9 +42,8 @@ enum __attribute__((flag_enum,enum_extensibility(open))) : GlobalOldName {
 
 #if __OBJC__
 @interface ColorMaker
-- (void)makeColorWithOptions:(SOColorMask)opts;
 - (void)makeOtherColorWithInt:(int) x withOptions:(CFColorMask)opts;
 @end
 #endif // SWIFT_OBJC_INTEROP
 
-#endif // TEST_INTEROP_CXX_ENUM_INPUTS_ANONYMOUS_WITH_SWIFT_NAME_H
\ No newline at end of file
+#endif // TEST_INTEROP_CXX_ENUM_INPUTS_ANONYMOUS_WITH_SWIFT_NAME_H
diff --git a/test/Interop/Cxx/enum/anonymous-with-swift-name-module-interface.swift b/test/Interop/Cxx/enum/anonymous-with-swift-name-module-interface.swift
index 6ed6c6d4ba488..021d004098c99 100644
--- a/test/Interop/Cxx/enum/anonymous-with-swift-name-module-interface.swift
+++ b/test/Interop/Cxx/enum/anonymous-with-swift-name-module-interface.swift
@@ -1,32 +1,5 @@
 // RUN: %target-swift-ide-test -print-module -module-to-print=AnonymousWithSwiftName -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
 
-// CHECK: @available(*, unavailable, message: "Not available in Swift")
-// CHECK: typealias SOColorMask = UInt32
-
-// CHECK: struct SOColorMask : OptionSet, @unchecked Sendable {
-// CHECK:   init(rawValue: UInt32)
-// CHECK:   let rawValue: UInt32
-// CHECK:   typealias RawValue = UInt32
-// CHECK:   typealias Element = SOColorMask
-// CHECK:   typealias ArrayLiteralElement = SOColorMask
-
-// CHECK:   static var red: SOColorMask { get }
-// CHECK:   @available(swift, obsoleted: 3, renamed: "red")
-// CHECK:   static var Red: SOColorMask { get }
-
-// CHECK:   static var green: SOColorMask { get }
-// CHECK:   @available(swift, obsoleted: 3, renamed: "green")
-// CHECK:   static var Green: SOColorMask { get }
-
-// CHECK:   static var blue: SOColorMask { get }
-// CHECK:   @available(swift, obsoleted: 3, renamed: "blue")
-// CHECK:   static var Blue: SOColorMask { get }
-
-// CHECK:   static var all: SOColorMask { get }
-// CHECK:   @available(swift, obsoleted: 3, renamed: "all")
-// CHECK:   static var All: SOColorMask { get }
-// CHECK: }
-
 // CHECK-NOT: typealias CFColorMask = UInt32
 
 // CHECK: struct CFColorMask : OptionSet {
@@ -53,7 +26,6 @@
 // CHECK:   static var All: CFColorMask { get }
 // CHECK: }
 
-// CHECK: func useSOColorMask(_ mask: SOColorMask) -> SOColorMask
 // CHECK: func useCFColorMask(_ mask: CFColorMask) -> CFColorMask
 
 // Test rename with "swift_name" attr:
diff --git a/test/Interop/Cxx/enum/anonymous-with-swift-name-objc-module-interface.swift b/test/Interop/Cxx/enum/anonymous-with-swift-name-objc-module-interface.swift
index 79a0f0ba2a69c..311aa0da1062d 100644
--- a/test/Interop/Cxx/enum/anonymous-with-swift-name-objc-module-interface.swift
+++ b/test/Interop/Cxx/enum/anonymous-with-swift-name-objc-module-interface.swift
@@ -3,12 +3,6 @@
 // REQUIRES: objc_interop
 
 // CHECK: class ColorMaker {
-// CHECK:   class func makeColor(withOptions opts: SOColorMask)
-// CHECK:   func makeColor(withOptions opts: SOColorMask)
-// CHECK:   @available(swift, obsoleted: 3, renamed: "makeColor(withOptions:)")
-// CHECK:   class func makeColorWithOptions(_ opts: SOColorMask)
-// CHECK:   @available(swift, obsoleted: 3, renamed: "makeColor(withOptions:)")
-// CHECK:   func makeColorWithOptions(_ opts: SOColorMask)
 // CHECK:   class func makeOtherColor(with x: Int32, withOptions opts: CFColorMask)
 // CHECK:   func makeOtherColor(with x: Int32, withOptions opts: CFColorMask)
 // CHECK:   @available(swift, obsoleted: 3, renamed: "makeOtherColor(with:withOptions:)")
diff --git a/test/Interop/Cxx/enum/anonymous-with-swift-name.swift b/test/Interop/Cxx/enum/anonymous-with-swift-name.swift
index 6c9beeed75964..906819550209f 100644
--- a/test/Interop/Cxx/enum/anonymous-with-swift-name.swift
+++ b/test/Interop/Cxx/enum/anonymous-with-swift-name.swift
@@ -7,18 +7,6 @@ import StdlibUnittest
 
 var AnonymousEnumsTestSuite = TestSuite("Anonymous Enums With Swift Name")
 
-AnonymousEnumsTestSuite.test("SOME_OPTIONS") {
-  let red: SOColorMask = .red
-  let green = SOColorMask.green
-  let blue = .blue as SOColorMask
-  let all: SOColorMask = .all
-
-  expectEqual(red.rawValue, 2)
-  expectEqual(green.rawValue, 4)
-  expectEqual(blue.rawValue, 8)
-   expectEqual(all.rawValue, ~CUnsignedInt(0))
-}
-
 AnonymousEnumsTestSuite.test("CF_OPTIONS") {
   let red: CFColorMask = .red
   let green = CFColorMask.green
@@ -35,8 +23,8 @@ AnonymousEnumsTestSuite.test("Parameter types") {
   let red: CFColorMask = .red
   let green = CFColorMask.green
 
-  let blue = useSOColorMask(.blue)
-  let all = useSOColorMask(.all)
+  let blue = useCFColorMask(.blue)
+  let all = useCFColorMask(.all)
 
   expectEqual(red, useCFColorMask(.red))
   expectEqual(green, useCFColorMask(.green))
diff --git a/test/Interop/Cxx/extern-var/extern-var-irgen.swift b/test/Interop/Cxx/extern-var/extern-var-irgen.swift
index cbec5e8e26828..8e6d985bd76a4 100644
--- a/test/Interop/Cxx/extern-var/extern-var-irgen.swift
+++ b/test/Interop/Cxx/extern-var/extern-var-irgen.swift
@@ -44,4 +44,4 @@ public func passingVarAsInout() {
 }
 
 // CHECK: define {{(protected |dllexport )?}}swiftcc void @"$s4main17passingVarAsInoutyyF"() #0
-// CHECK: call swiftcc void @"$s4main11modifyInoutyys5Int32VzF"(ptr nocapture dereferenceable(4) @{{counter|"\?counter@@3HA"}})
+// CHECK: call swiftcc void @"$s4main11modifyInoutyys5Int32VzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable(4) @{{counter|"\?counter@@3HA"}})
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/ReferenceCounted.apinotes b/test/Interop/Cxx/foreign-reference/Inputs/ReferenceCounted.apinotes
new file mode 100644
index 0000000000000..344bf18037cfe
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/Inputs/ReferenceCounted.apinotes
@@ -0,0 +1,8 @@
+---
+Name: ReferenceCounted
+Tags:
+- Name: OpaqueRefImpl
+  SwiftImportAs: reference
+  SwiftRetainOp: OPRetain
+  SwiftReleaseOp: OPRelease
+
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/cxx-functions-and-methods-returning-frt.h b/test/Interop/Cxx/foreign-reference/Inputs/cxx-functions-and-methods-returning-frt.h
index 3588fd87e5276..819fc54e2642f 100644
--- a/test/Interop/Cxx/foreign-reference/Inputs/cxx-functions-and-methods-returning-frt.h
+++ b/test/Interop/Cxx/foreign-reference/Inputs/cxx-functions-and-methods-returning-frt.h
@@ -1,4 +1,5 @@
 #pragma once
+#include "visibility.h"
 #include <functional>
 
 // FRT or SWIFT_SHARED_REFERENCE type
@@ -146,7 +147,7 @@ struct StructWithStaticMethodsReturningFRTWithAttributeReturnsUnretained {
 // Global/free C++ functions returning FRT with both attributes
 // swift_attr("returns_unretained") and swift_attr("returns_retained")
 FRTStruct
-    *_Nonnull global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained()
+    *_Nonnull global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained() // expected-error {{'global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained' cannot be annotated with both SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED}}
         __attribute__((swift_attr("returns_retained")))
         __attribute__((swift_attr("returns_unretained")));
 
@@ -154,7 +155,7 @@ FRTStruct
 // swift_attr("returns_unretained") and swift_attr("returns_retained")
 struct
     StructWithStaticMethodsReturningFRTWithBothAttributesReturnsRetainedAndReturnsUnretained {
-  static FRTStruct *_Nonnull StaticMethodReturningFRT()
+  static FRTStruct *_Nonnull StaticMethodReturningFRT() // expected-error {{'StaticMethodReturningFRT' cannot be annotated with both SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED}}
       __attribute__((swift_attr("returns_retained")))
       __attribute__((swift_attr("returns_unretained")));
 };
@@ -178,50 +179,50 @@ __attribute__((swift_attr("unsafe")));
 
 // C++ APIs returning cxx frts (for testing diagnostics)
 struct StructWithAPIsReturningCxxFrt {
-  static FRTStruct *_Nonnull StaticMethodReturningCxxFrt();
+  static FRTStruct *_Nonnull StaticMethodReturningCxxFrt(); // expected-note {{'StaticMethodReturningCxxFrt()' is defined here}}
   static FRTStruct *_Nonnull StaticMethodReturningCxxFrtWithAnnotation()
       __attribute__((swift_attr("returns_retained")));
 };
 
-FRTStruct *_Nonnull global_function_returning_cxx_frt();
+FRTStruct *_Nonnull global_function_returning_cxx_frt(); // expected-note {{'global_function_returning_cxx_frt()' is defined here}}
 FRTStruct *_Nonnull global_function_returning_cxx_frt_with_annotations()
     __attribute__((swift_attr("returns_retained")));
 
 // C++ APIs returning non-cxx-frts (for testing diagnostics)
 struct StructWithAPIsReturningNonCxxFrt {
   static NonFRTStruct *_Nonnull StaticMethodReturningNonCxxFrt();
-  static NonFRTStruct *_Nonnull StaticMethodReturningNonCxxFrtWithAnnotation()
+  static NonFRTStruct *_Nonnull StaticMethodReturningNonCxxFrtWithAnnotation() // expected-warning {{'StaticMethodReturningNonCxxFrtWithAnnotation' should not be annotated with SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
       __attribute__((swift_attr("returns_retained")));
 };
 
 NonFRTStruct *_Nonnull global_function_returning_non_cxx_frt();
-NonFRTStruct *_Nonnull global_function_returning_non_cxx_frt_with_annotations()
+NonFRTStruct *_Nonnull global_function_returning_non_cxx_frt_with_annotations() // expected-warning {{'global_function_returning_non_cxx_frt_with_annotations' should not be annotated with SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
     __attribute__((swift_attr("returns_retained")));
 
 // C++ APIs returning SWIFT_IMMORTAL_REFERENCE types (for testing diagnostics)
 struct StructWithAPIsReturningImmortalReference {
   static ImmortalRefStruct *_Nonnull StaticMethodReturningImmortalReference();
   static ImmortalRefStruct
-      *_Nonnull StaticMethodReturningImmortalReferenceWithAnnotation()
+      *_Nonnull StaticMethodReturningImmortalReferenceWithAnnotation() // expected-warning {{'StaticMethodReturningImmortalReferenceWithAnnotation' should not be annotated with SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
           __attribute__((swift_attr("returns_retained")));
 };
 
 ImmortalRefStruct *_Nonnull global_function_returning_immortal_reference();
 ImmortalRefStruct
-    *_Nonnull global_function_returning_immortal_reference_with_annotations()
+    *_Nonnull global_function_returning_immortal_reference_with_annotations() // expected-warning {{'global_function_returning_immortal_reference_with_annotations' should not be annotated with SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
         __attribute__((swift_attr("returns_retained")));
 
 // C++ APIs returning SWIFT_UNSAFE_REFERENCE types (for testing diagnostics)
 struct StructWithAPIsReturningUnsafeReference {
   static UnsafeRefStruct *_Nonnull StaticMethodReturningUnsafeReference();
   static UnsafeRefStruct
-      *_Nonnull StaticMethodReturningUnsafeReferenceWithAnnotation()
+      *_Nonnull StaticMethodReturningUnsafeReferenceWithAnnotation() // expected-warning {{'StaticMethodReturningUnsafeReferenceWithAnnotation' should not be annotated with SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
           __attribute__((swift_attr("returns_retained")));
 };
 
 UnsafeRefStruct *_Nonnull global_function_returning_unsafe_reference();
 UnsafeRefStruct
-    *_Nonnull global_function_returning_unsafe_reference_with_annotations()
+    *_Nonnull global_function_returning_unsafe_reference_with_annotations() // expected-warning {{'global_function_returning_unsafe_reference_with_annotations' should not be annotated with SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
         __attribute__((swift_attr("returns_retained")));
 
 // Global/free C++ functions returning non-FRT
@@ -296,13 +297,13 @@ __attribute__((swift_attr(
 
 public:
   FRTOverloadedOperators *_Nonnull
-  operator+(const FRTOverloadedOperators &other)
+  operator+(const FRTOverloadedOperators &other) // expected-warning {{SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED is not supported yet for overloaded C++ 'operator+'. Overloaded C++ operators always return SWIFT_SHARED_REFERENCE types as owned}}
       __attribute__((swift_attr("returns_unretained")));
   FRTOverloadedOperators *_Nonnull
   operator-(const FRTOverloadedOperators &other);
 };
 
-FRTOverloadedOperators *_Nonnull returnFRTOverloadedOperators();
+FRTOverloadedOperators *_Nonnull returnFRTOverloadedOperators(); // expected-note {{'returnFRTOverloadedOperators()' is defined here}} // expected-note {{'returnFRTOverloadedOperators()' is defined here}}
 
 void retain_FRTOverloadedOperators(FRTOverloadedOperators *_Nonnull v);
 void release_FRTOverloadedOperators(FRTOverloadedOperators *_Nonnull v);
@@ -326,3 +327,192 @@ struct Derived : Base {
   FRTStruct *_Nonnull VirtualMethodReturningFRTUnowned() override
       __attribute__((swift_attr("returns_unretained")));
 };
+
+SWIFT_BEGIN_NULLABILITY_ANNOTATIONS
+
+namespace DefaultOwnershipConventionOnCXXForeignRefType {
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:defRetain2")))
+__attribute__((swift_attr("release:defRelease2"))) 
+__attribute__((swift_attr("returned_as_unretained_by_default"))) RefTyDefUnretained {};
+
+RefTyDefUnretained *returnRefTyDefUnretained() {
+  return new RefTyDefUnretained();
+}
+} // namespace DefaultOwnershipConventionOnCXXForeignRefType
+
+void defRetain2(
+    DefaultOwnershipConventionOnCXXForeignRefType::RefTyDefUnretained *v) {};
+void defRelease2(
+    DefaultOwnershipConventionOnCXXForeignRefType::RefTyDefUnretained *v) {};
+
+namespace FunctionAnnotationHasPrecedence {
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:defaultRetain1")))
+__attribute__((swift_attr("release:defaultRelease1")))
+__attribute__((swift_attr("returned_as_unretained_by_default"))) RefTyDefUnretained {};
+
+RefTyDefUnretained *returnRefTyDefUnretained() {
+  return new RefTyDefUnretained();
+}
+RefTyDefUnretained *returnRefTyDefUnretainedAnnotatedRetained()
+    __attribute__((swift_attr("returns_retained"))) {
+  return new RefTyDefUnretained();
+}
+
+} // namespace FunctionAnnotationHasPrecedence
+
+void defaultRetain1(FunctionAnnotationHasPrecedence::RefTyDefUnretained *v) {};
+void defaultRelease1(FunctionAnnotationHasPrecedence::RefTyDefUnretained *v) {};
+
+namespace DefaultOwnershipSuppressUnannotatedAPIWarning {
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:rretain")))
+__attribute__((swift_attr("release:rrelease"))) RefType {};
+
+RefType *returnRefType() { return new RefType(); } // expected-note {{'returnRefType()' is defined here}}
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:dretain")))
+__attribute__((swift_attr("release:drelease"))) 
+__attribute__((swift_attr("returned_as_unretained_by_default"))) RefTyDefUnretained {};
+
+RefTyDefUnretained *returnRefTyDefUnretainedd() { return new RefTyDefUnretained(); }
+
+} // namespace DefaultOwnershipSuppressUnannotatedAPIWarning
+
+void rretain(DefaultOwnershipSuppressUnannotatedAPIWarning::RefType *v) {};
+void rrelease(DefaultOwnershipSuppressUnannotatedAPIWarning::RefType *v) {};
+
+void dretain(
+    DefaultOwnershipSuppressUnannotatedAPIWarning::RefTyDefUnretained *v) {};
+void drelease(
+    DefaultOwnershipSuppressUnannotatedAPIWarning::RefTyDefUnretained *v) {};
+
+namespace DefaultOwnershipInheritance {
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:baseRetain")))
+__attribute__((swift_attr("release:baseRelease")))
+__attribute__((swift_attr("returned_as_unretained_by_default"))) BaseType {};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:derivedRetain")))
+__attribute__((swift_attr("release:derivedRelease"))) DerivedType
+    : public BaseType {};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:derivedRetain2")))
+__attribute__((swift_attr("release:derivedRelease2"))) DerivedType2
+    : public DerivedType {};
+
+BaseType *createBaseType() { return new BaseType(); }
+DerivedType *createDerivedType() { return new DerivedType(); }
+DerivedType2 *createDerivedType2() { return new DerivedType2(); }
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:bRetain")))
+__attribute__((swift_attr("release:bRelease"))) BaseTypeNonDefault {};
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:dRetain")))
+__attribute__((swift_attr("release:dRelease"))) DerivedTypeNonDefault
+    : public BaseTypeNonDefault {};
+
+BaseTypeNonDefault *createBaseTypeNonDefault() { // expected-note {{'createBaseTypeNonDefault()' is defined here}}
+  return new BaseTypeNonDefault();
+}
+DerivedTypeNonDefault *createDerivedTypeNonDefault() { // expected-note {{'createDerivedTypeNonDefault()' is defined here}}
+    return new DerivedTypeNonDefault();
+}
+
+DerivedTypeNonDefault *createDerivedTypeNonDefaultUnretained()
+    __attribute__((swift_attr("returns_unretained"))) {
+  return new DerivedTypeNonDefault();
+}
+
+} // namespace DefaultOwnershipInheritance
+
+void baseRetain(DefaultOwnershipInheritance::BaseType *v) {};
+void baseRelease(DefaultOwnershipInheritance::BaseType *v) {};
+
+void derivedRetain(DefaultOwnershipInheritance::DerivedType *v) {};
+void derivedRelease(DefaultOwnershipInheritance::DerivedType *v) {};
+
+void derivedRetain2(DefaultOwnershipInheritance::DerivedType2 *v) {};
+void derivedRelease2(DefaultOwnershipInheritance::DerivedType2 *v) {};
+
+void bRetain(DefaultOwnershipInheritance::BaseTypeNonDefault *v) {};
+void bRelease(DefaultOwnershipInheritance::BaseTypeNonDefault *v) {};
+
+void dRetain(DefaultOwnershipInheritance::DerivedTypeNonDefault *v) {};
+void dRelease(DefaultOwnershipInheritance::DerivedTypeNonDefault *v) {};
+
+namespace SourceLocationCaching {
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retain_SourceLocCacheA")))
+__attribute__((swift_attr("release:release_SourceLocCacheA"))) TypeA {};
+
+
+
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retain_SourceLocCacheB")))
+__attribute__((swift_attr("release:release_SourceLocCacheB"))) TypeB {};
+
+
+template <typename T>
+struct Factory {
+  static T *make() { return new T(); } // expected-note {{'make()' is defined here}} // expected-note {{'make()' is defined here}}
+};
+
+using FactoryA = Factory<TypeA>;
+using FactoryB = Factory<TypeB>;
+
+} // namespace SourceLocationCaching
+
+void retain_SourceLocCacheA(SourceLocationCaching::TypeA *) {}
+void release_SourceLocCacheA(SourceLocationCaching::TypeA *) {}
+
+void retain_SourceLocCacheB(SourceLocationCaching::TypeB *) {}
+void release_SourceLocCacheB(SourceLocationCaching::TypeB *) {}
+
+
+template <typename T>
+class RefTemplate {
+public:
+  // These should now be importable with the fix
+  T* ptr() const __attribute__((swift_attr("returns_retained"))) {
+    return nullptr;
+  }
+
+  T* get() const __attribute__((swift_attr("returns_unretained"))) {
+    return nullptr;
+  }
+
+  T* value() const {
+    return nullptr;
+  }
+};
+
+template <>
+class RefTemplate<FRTStruct> {
+public:
+  FRTStruct* ptr() const __attribute__((swift_attr("returns_retained"))) {
+    return new FRTStruct;
+  }
+
+  FRTStruct* get() const __attribute__((swift_attr("returns_unretained"))) {
+    static FRTStruct instance;
+    return &instance;
+  }
+
+  FRTStruct* value() const { // expected-note {{'value()' is defined here}}
+    return new FRTStruct;
+  }
+};
+
+using FRTStructRef = RefTemplate<FRTStruct>;
+
+SWIFT_END_NULLABILITY_ANNOTATIONS
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/frt-reference-returns.h b/test/Interop/Cxx/foreign-reference/Inputs/frt-reference-returns.h
new file mode 100644
index 0000000000000..dbe1eadecd505
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/Inputs/frt-reference-returns.h
@@ -0,0 +1,71 @@
+#pragma once
+
+namespace NoAnnotations {
+
+struct RefCountedType {
+  int value;
+} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retainRefCounted")))
+__attribute__((swift_attr("release:releaseRefCounted")));
+
+RefCountedType& getRefCountedByRef(); // expected-note {{'getRefCountedByRef()' is defined here}}
+RefCountedType& createRefCountedByRef(); // expected-note {{'createRefCountedByRef()' is defined here}}
+RefCountedType& copyRefCountedByRef(); // expected-note {{'copyRefCountedByRef()' is defined here}}   
+
+} // namespace NoAnnotations
+
+void retainRefCounted(NoAnnotations::RefCountedType* obj);
+void releaseRefCounted(NoAnnotations::RefCountedType* obj);
+
+namespace APIAnnotations {
+
+struct RefCountedType {
+  int value;
+} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retainAPIRefCounted")))
+__attribute__((swift_attr("release:releaseAPIRefCounted")));
+
+RefCountedType& createByRef() __attribute__((swift_attr("returns_retained")));
+RefCountedType& getByRef() __attribute__((swift_attr("returns_unretained")));
+
+
+} // namespace APIAnnotations
+
+void retainAPIRefCounted(APIAnnotations::RefCountedType* obj);
+void releaseAPIRefCounted(APIAnnotations::RefCountedType* obj);
+
+namespace TypeAnnotation {
+
+struct RefCountedType {
+  int value;
+} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retainTypeRefCounted")))
+__attribute__((swift_attr("release:releaseTypeRefCounted")))
+__attribute__((swift_attr("returned_as_unretained_by_default")));
+
+RefCountedType& getByRef();
+RefCountedType& createByRef();
+RefCountedType& copyByRef();
+
+} // namespace TypeAnnotation
+
+void retainTypeRefCounted(TypeAnnotation::RefCountedType* obj);
+void releaseTypeRefCounted(TypeAnnotation::RefCountedType* obj);
+
+namespace BothAnnotations {
+
+struct RefCountedType {
+  int value;
+} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retainBothRefCounted")))
+__attribute__((swift_attr("release:releaseBothRefCounted")))
+__attribute__((swift_attr("returned_as_unretained_by_default")));
+
+// Note: Type default at type level is unretained, but API annotation overrides
+RefCountedType& createByRef() __attribute__((swift_attr("returns_retained")));
+RefCountedType& getByRef();
+
+} // namespace BothAnnotations
+
+void retainBothRefCounted(BothAnnotations::RefCountedType* obj);
+void releaseBothRefCounted(BothAnnotations::RefCountedType* obj);
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/incomplete.c b/test/Interop/Cxx/foreign-reference/Inputs/incomplete.c
new file mode 100644
index 0000000000000..8cb57b156ae3b
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/Inputs/incomplete.c
@@ -0,0 +1,55 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "reference-counted.h"
+
+typedef struct IncompleteImpl {
+  unsigned refCount;
+  double weight;
+} *Incomplete;
+
+
+Incomplete Incomplete_create(double weight) {
+  Incomplete result = (Incomplete)malloc(sizeof(struct IncompleteImpl));
+  result->refCount = 1;
+  result->weight = weight;
+  return result;
+}
+
+void INRetain(Incomplete i) {
+  i->refCount++;
+}
+
+void INRelease(Incomplete i) {
+  i->refCount--;
+  if (i->refCount == 0) {
+    printf("Destroyed instance containing weight %f\n", i->weight);
+    free(i);
+  }
+}
+
+double Incomplete_getWeight(Incomplete i) {
+  return i->weight;
+}
+
+struct OpaqueRefImpl {
+  unsigned refCount;
+};
+
+OpaqueRef Opaque_create(void) {
+  OpaqueRef result = (OpaqueRef)malloc(sizeof(struct OpaqueRefImpl));
+  result->refCount = 1;
+  return result;
+}
+
+void OPRetain(OpaqueRef i) {
+  i->refCount++;
+}
+
+void OPRelease(OpaqueRef i) {
+  i->refCount--;
+  if (i->refCount == 0) {
+    printf("Destroyed OpaqueRef instance\n");
+    free(i);
+  }
+}
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/inheritance.h b/test/Interop/Cxx/foreign-reference/Inputs/inheritance.h
index f993a65ab200c..5b4aa0f2b97b1 100644
--- a/test/Interop/Cxx/foreign-reference/Inputs/inheritance.h
+++ b/test/Interop/Cxx/foreign-reference/Inputs/inheritance.h
@@ -5,6 +5,13 @@
 // A wrapper around C++'s static_cast(), which allows Swift to get around interop's current lack of support for inheritance.
 template <class I, class O> O cxxCast(I i) { return static_cast<O>(i); }
 
+namespace Foo {
+template <class I, class O>
+O cxxCast(I i) {
+  return static_cast<O>(i);
+}
+} // namespace Foo
+
 // A minimal foreign reference type.
 struct
 __attribute__((swift_attr("import_reference")))
@@ -102,7 +109,7 @@ __attribute__((swift_attr("release:immortal"))) ImmortalRefType {};
 ImmortalRefType *returnImmortalRefType() { return new ImmortalRefType(); };
 
 struct DerivedFromImmortalRefType : ImmortalRefType {};
-DerivedFromImmortalRefType *returnDerivedFromImmortalRefType() {
+DerivedFromImmortalRefType *returnDerivedFromImmortalRefType() { // expected-note {{'returnDerivedFromImmortalRefType()' is defined here}}
     return new DerivedFromImmortalRefType();
 };
 
@@ -115,7 +122,7 @@ ValueType *returnValueType() { return new ValueType(); }
 struct __attribute__((swift_attr("import_reference")))
 __attribute__((swift_attr("retain:ret1")))
 __attribute__((swift_attr("release:rel1"))) RefType {};
-RefType *returnRefType() { return new RefType(); } // expected-warning {{'returnRefType' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
+RefType *returnRefType() { return new RefType(); } // expected-note {{'returnRefType()' is defined here}}
 
 struct DerivedFromValueType : ValueType {};
 DerivedFromValueType *returnDerivedFromValueType() {
@@ -126,12 +133,12 @@ struct __attribute__((swift_attr("import_reference")))
 __attribute__((swift_attr("retain:ret2")))
 __attribute__((swift_attr("release:rel2"))) DerivedFromValueTypeAndAnnotated
     : ValueType {};
-DerivedFromValueTypeAndAnnotated *returnDerivedFromValueTypeAndAnnotated() { // expected-warning {{'returnDerivedFromValueTypeAndAnnotated' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
+DerivedFromValueTypeAndAnnotated *returnDerivedFromValueTypeAndAnnotated() { // expected-note {{'returnDerivedFromValueTypeAndAnnotated()' is defined here}}
     return new DerivedFromValueTypeAndAnnotated();
 }
 
 struct DerivedFromRefType final : RefType {};
-DerivedFromRefType *returnDerivedFromRefType() {
+DerivedFromRefType *returnDerivedFromRefType() { // expected-note {{'returnDerivedFromRefType()' is defined here}}
     return new DerivedFromRefType();
 }
 
@@ -139,7 +146,7 @@ struct __attribute__((swift_attr("import_reference")))
 __attribute__((swift_attr("retain:ret3")))
 __attribute__((swift_attr("release:rel3"))) DerivedFromRefTypeAndAnnotated
     : RefType {};
-DerivedFromRefTypeAndAnnotated *returnDerivedFromRefTypeAndAnnotated() { // expected-warning {{'returnDerivedFromRefTypeAndAnnotated' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
+DerivedFromRefTypeAndAnnotated *returnDerivedFromRefTypeAndAnnotated() { // expected-note {{'returnDerivedFromRefTypeAndAnnotated()' is defined here}}
     return new DerivedFromRefTypeAndAnnotated();
 }
 } // namespace ExplicitAnnotationHasPrecedence1
@@ -177,7 +184,7 @@ __attribute__((swift_attr("retain:retain_C")))
 __attribute__((swift_attr("release:release_C"))) DerivedFromRefTypeAAndBAnnotated
     : RefTypeA,
         RefTypeB {};
-DerivedFromRefTypeAAndBAnnotated *returnDerivedFromRefTypeAAndBAnnotated() { // expected-warning {{'returnDerivedFromRefTypeAAndBAnnotated' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
+DerivedFromRefTypeAAndBAnnotated *returnDerivedFromRefTypeAAndBAnnotated() { // expected-note {{'returnDerivedFromRefTypeAAndBAnnotated()' is defined here}}
     return new DerivedFromRefTypeAAndBAnnotated();
 }
 } // namespace ExplicitAnnotationHasPrecedence2
@@ -199,10 +206,10 @@ struct __attribute__((swift_attr("import_reference")))
 __attribute__((swift_attr("retain:RCRetain")))
 __attribute__((swift_attr("release:RCRelease"))) RefType {};
 
-RefType *returnRefType() { return new RefType(); }; // expected-warning {{'returnRefType' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENC}}
+RefType *returnRefType() { return new RefType(); }; // expected-note {{'returnRefType()' is defined here}}
 
 struct DerivedFromRefType final : RefType {};
-DerivedFromRefType *returnDerivedFromRefType() { // TODO: rdar://145098078 Missing SWIFT_RETURNS_(UN)RETAINED annotation warning should trigger for inferred foreeign reference types as well
+DerivedFromRefType *returnDerivedFromRefType() { // expected-note {{'returnDerivedFromRefType()' is defined here}}
   return new DerivedFromRefType();
 };
 } // namespace BasicInheritanceExample
@@ -229,7 +236,7 @@ DerivedFromBaseRef1AndBaseRef2 *returnDerivedFromBaseRef1AndBaseRef2() {
 };
 
 struct DerivedFromBaseRef3 : BaseRef3 {};
-DerivedFromBaseRef3 *returnDerivedFromBaseRef3() {
+DerivedFromBaseRef3 *returnDerivedFromBaseRef3() { // expected-note {{'returnDerivedFromBaseRef3()' is defined here}}
   return new DerivedFromBaseRef3();
 };
 } // namespace MultipleInheritanceExample1
@@ -305,7 +312,7 @@ __attribute__((swift_attr("release:samerelease"))) B2 {};  // expected-error {{m
 
 struct D : B1, B2 {}; // expected-error {{multiple functions 'sameretain' found; there must be exactly one retain function for reference type 'D'}}
                       // expected-error@-1 {{multiple functions 'samerelease' found; there must be exactly one release function for reference type 'D'}}
-D *returnD() { return new D(); };
+D *returnD() { return new D(); }; // expected-note {{'returnD()' is defined here}}
 } // namespace OverloadedRetainRelease
 
 void sameretain(OverloadedRetainRelease::B1 *v) {}
@@ -332,7 +339,7 @@ struct BVirtual : virtual A {};
 struct CVirtual : virtual A {};
 
 struct VirtualDiamond : BVirtual, CVirtual {};
-VirtualDiamond *returnVirtualDiamond() { return new VirtualDiamond(); };
+VirtualDiamond *returnVirtualDiamond() { return new VirtualDiamond(); }; // expected-note {{'returnVirtualDiamond()' is defined here}}
 } // namespace RefTypeDiamondInheritance
 
 void retainA(RefTypeDiamondInheritance::A *a) {};
@@ -348,7 +355,7 @@ __attribute__((swift_attr("release:releaseB"))) B : A {};
 struct C : A {};
 
 struct Diamond : B, C {};
-Diamond *returnDiamond() { return new Diamond(); };
+Diamond *returnDiamond() { return new Diamond(); }; // expected-note {{'returnDiamond()' is defined here}}
 
 } // namespace NonRefTypeDiamondInheritance
 
@@ -377,7 +384,7 @@ __attribute__((swift_attr("retain:forestRetain"))) __attribute__((
 };
 
 class Forest : public IntrusiveRefCountedTemplate<Forest> {};
-Forest *returnForest() { return new Forest(); };
+Forest *returnForest() { return new Forest(); }; // expected-note {{'returnForest()' is defined here}}
 } // namespace InheritingTemplatedRefType
 
 void forestRetain(InheritingTemplatedRefType::IntrusiveRefCountedTemplate<
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/lifetime-operation-methods.h b/test/Interop/Cxx/foreign-reference/Inputs/lifetime-operation-methods.h
new file mode 100644
index 0000000000000..1eac66fbe2cd0
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/Inputs/lifetime-operation-methods.h
@@ -0,0 +1,121 @@
+#include <swift/bridging>
+
+struct RefCountedBox {
+  int value;
+  int refCount = 1;
+
+  RefCountedBox(int value) : value(value) {}
+
+  void doRetain() { refCount++; }
+  void doRelease() { refCount--; }
+} SWIFT_SHARED_REFERENCE(.doRetain, .doRelease);
+
+struct DerivedRefCountedBox : RefCountedBox {
+  int secondValue = 1;
+  DerivedRefCountedBox(int value, int secondValue)
+      : RefCountedBox(value), secondValue(secondValue) {}
+};
+
+// MARK: Retain in a base type, release in derived
+
+struct BaseHasRetain {
+  mutable int refCount = 1;
+  void doRetainInBase() const { refCount++; }
+};
+
+struct DerivedHasRelease : BaseHasRetain {
+  int value;
+  DerivedHasRelease(int value) : value(value) {}
+
+  void doRelease() const { refCount--; }
+} SWIFT_SHARED_REFERENCE(.doRetainInBase, .doRelease);
+
+// MARK: Retain in a base type, release in templated derived
+
+template <typename T>
+struct TemplatedDerivedHasRelease : BaseHasRetain {
+  T value;
+  TemplatedDerivedHasRelease(T value) : value(value) {}
+
+  void doReleaseTemplated() const { refCount--; }
+} SWIFT_SHARED_REFERENCE(.doRetainInBase, .doReleaseTemplated);
+
+using TemplatedDerivedHasReleaseFloat = TemplatedDerivedHasRelease<float>;
+using TemplatedDerivedHasReleaseInt = TemplatedDerivedHasRelease<int>;
+
+// MARK: Retain/release in CRTP base type
+
+template <typename Derived>
+struct CRTPBase {
+  mutable int refCount = 1;
+  void crtpRetain() const { refCount++; }
+  void crtpRelease() const { refCount--; }
+} SWIFT_SHARED_REFERENCE(.crtpRetain, .crtpRelease);
+
+struct CRTPDerived : CRTPBase<CRTPDerived> {
+  int value;
+  CRTPDerived(int value) : value(value) {}
+};
+
+// MARK: Virtual retain and release
+
+struct VirtualRetainRelease {
+  int value;
+  mutable int refCount = 1;
+  mutable bool calledBase = false;
+  VirtualRetainRelease(int value) : value(value) {}
+
+  virtual void doRetainVirtual() const { refCount++; calledBase = true; }
+  virtual void doReleaseVirtual() const { refCount--; calledBase = true; }
+  virtual ~VirtualRetainRelease() = default;
+} SWIFT_SHARED_REFERENCE(.doRetainVirtual, .doReleaseVirtual);
+
+struct DerivedVirtualRetainRelease : VirtualRetainRelease {
+  DerivedVirtualRetainRelease(int value) : VirtualRetainRelease(value) {}
+
+  void doRetainVirtual() const override { refCount++; }
+  void doReleaseVirtual() const override { refCount--; }
+};
+
+// MARK: Pure virtual retain and release
+
+struct PureVirtualRetainRelease {
+  int value;
+  mutable int refCount = 1;
+  PureVirtualRetainRelease(int value) : value(value) {}
+
+  virtual void doRetainPure() const = 0;
+  virtual void doReleasePure() const = 0;
+  virtual ~PureVirtualRetainRelease() = default;
+} SWIFT_SHARED_REFERENCE(.doRetainPure, .doReleasePure);
+
+struct DerivedPureVirtualRetainRelease : PureVirtualRetainRelease {
+  mutable int refCount = 1;
+
+  DerivedPureVirtualRetainRelease(int value) : PureVirtualRetainRelease(value) {}
+  void doRetainPure() const override { refCount++; }
+  void doReleasePure() const override { refCount--; }
+};
+
+// MARK: Static retain/release
+#ifdef INCORRECT
+struct StaticRetainRelease {
+// expected-error@-1 {{specified retain function '.staticRetain' is a static function; expected an instance function}}
+// expected-error@-2 {{specified release function '.staticRelease' is a static function; expected an instance function}}
+  int value;
+  int refCount = 1;
+
+  StaticRetainRelease(int value) : value(value) {}
+
+  static void staticRetain(StaticRetainRelease* o) { o->refCount++; }
+  static void staticRelease(StaticRetainRelease* o) { o->refCount--; }
+} SWIFT_SHARED_REFERENCE(.staticRetain, .staticRelease);
+
+struct DerivedStaticRetainRelease : StaticRetainRelease {
+// expected-error@-1 {{cannot find retain function '.staticRetain' for reference type 'DerivedStaticRetainRelease'}}
+// expected-error@-2 {{cannot find release function '.staticRelease' for reference type 'DerivedStaticRetainRelease'}}
+  int secondValue = 1;
+  DerivedStaticRetainRelease(int value, int secondValue)
+      : StaticRetainRelease(value), secondValue(secondValue) {}
+};
+#endif
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/logging-frts.h b/test/Interop/Cxx/foreign-reference/Inputs/logging-frts.h
new file mode 100644
index 0000000000000..08ff830d54ed7
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/Inputs/logging-frts.h
@@ -0,0 +1,87 @@
+#pragma once
+
+#include <stdio.h>
+#include <swift/bridging>
+
+class SharedFRT {
+public:
+  SharedFRT() : _refCount(1) { logMsg("Ctor"); }
+
+protected:
+  virtual ~SharedFRT() { logMsg("Dtor"); }
+
+private:
+  void logMsg(const char *s) const {
+    printf("RefCount: %d, message: %s\n", _refCount, s);
+  }
+
+  SharedFRT(const SharedFRT &) = delete;
+  SharedFRT &operator=(const SharedFRT &) = delete;
+  SharedFRT(SharedFRT &&) = delete;
+  SharedFRT &operator=(SharedFRT &&) = delete;
+
+  int _refCount;
+
+  friend void retainSharedFRT(SharedFRT *_Nonnull);
+  friend void releaseSharedFRT(SharedFRT *_Nonnull);
+} SWIFT_SHARED_REFERENCE(retainSharedFRT, releaseSharedFRT);
+
+class MyToken {
+public:
+  MyToken() = default;
+  MyToken(MyToken const &) {}
+};
+
+inline void retainSharedFRT(SharedFRT *_Nonnull x) {
+  ++x->_refCount;
+  x->logMsg("retain");
+}
+
+inline void releaseSharedFRT(SharedFRT *_Nonnull x) {
+  --x->_refCount;
+  x->logMsg("release");
+  if (x->_refCount == 0)
+    delete x;
+}
+
+struct LargeStructWithRefCountedField {
+  void const *a;
+  void const *b;
+  unsigned long c;
+  unsigned d;
+  SharedFRT *e;
+};
+
+struct LargeStructWithRefCountedFieldNested {
+  int a;
+  LargeStructWithRefCountedField b;
+};
+
+inline LargeStructWithRefCountedField getStruct() {
+  return {0, 0, 0, 0, new SharedFRT()};
+}
+
+inline LargeStructWithRefCountedFieldNested getNestedStruct() {
+  return {0, {0, 0, 0, 0, new SharedFRT()}};
+}
+
+template <class T>
+struct Ref {
+  T *_Nonnull ptr() const { return ref; }
+  T *ref;
+};
+
+class Payload final : public SharedFRT {
+public:
+  static Ref<Payload> create(int value) {
+    Ref<Payload> ref;
+    ref.ref = new Payload(value);
+    return ref;
+  }
+
+  int value() const { return m_value; }
+
+private:
+  explicit Payload(int value) : m_value(value) {}
+  int m_value;
+};
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/member-inheritance.h b/test/Interop/Cxx/foreign-reference/Inputs/member-inheritance.h
index 1cf75adf6926c..6cabedcd45ec1 100644
--- a/test/Interop/Cxx/foreign-reference/Inputs/member-inheritance.h
+++ b/test/Interop/Cxx/foreign-reference/Inputs/member-inheritance.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#define FRT                                       \
+#define IMMORTAL_FRT                              \
   __attribute__((swift_attr("import_reference"))) \
   __attribute__((swift_attr("retain:immortal")))  \
   __attribute__((swift_attr("release:immortal")))
@@ -28,7 +28,7 @@ class CopyTrackedBaseClass {
     }
 private:
     int x;
-} FRT;
+} IMMORTAL_FRT;
 
 class CopyTrackedDerivedClass: public CopyTrackedBaseClass {
 public:
@@ -37,7 +37,7 @@ class CopyTrackedDerivedClass: public CopyTrackedBaseClass {
     int getDerivedX() const {
         return getX();
     }
-} FRT;
+} IMMORTAL_FRT;
 
 CopyTrackedDerivedClass *makeCopyTrackedDerivedClass(int x) {
     return new CopyTrackedDerivedClass(x);
@@ -50,12 +50,12 @@ class NonEmptyBase {
     }
 private:
     int y = 11;
-} FRT;
+} IMMORTAL_FRT;
 
 class CopyTrackedDerivedDerivedClass: public NonEmptyBase, public CopyTrackedDerivedClass {
 public:
     CopyTrackedDerivedDerivedClass(int x) : CopyTrackedDerivedClass(x) {}
-} FRT;
+} IMMORTAL_FRT;
 
 CopyTrackedDerivedDerivedClass *makeCopyTrackedDerivedDerivedClass(int x) {
     return new CopyTrackedDerivedDerivedClass(x);
@@ -66,15 +66,14 @@ class BaseReturningFRTFromSubscript {
     CopyTrackedDerivedClass &operator[](int x) const {
         return *new CopyTrackedDerivedClass(x);
     }
-} FRT;
+} IMMORTAL_FRT;
 
 BaseReturningFRTFromSubscript *makeBaseReturningFRTFromSubscript() {
     return new BaseReturningFRTFromSubscript();
 }
 
-class DerivedFromBaseReturningFRTFromSubscript: public BaseReturningFRTFromSubscript {
-public:
-} FRT;
+class DerivedFromBaseReturningFRTFromSubscript
+    : public BaseReturningFRTFromSubscript{public : } IMMORTAL_FRT;
 
 DerivedFromBaseReturningFRTFromSubscript *makeDerivedFromBaseReturningFRTFromSubscript() {
     return new DerivedFromBaseReturningFRTFromSubscript();
@@ -90,12 +89,279 @@ class BaseReturningFRTFromSubscriptPointer {
 
 private:
     CopyTrackedDerivedClass *value;
-} FRT;
+} IMMORTAL_FRT;
 
-class DerivedFromBaseReturningFRTFromSubscriptPointer: public BaseReturningFRTFromSubscriptPointer {
-public:
-} FRT;
+class DerivedFromBaseReturningFRTFromSubscriptPointer
+    : public BaseReturningFRTFromSubscriptPointer{public : } IMMORTAL_FRT;
 
 DerivedFromBaseReturningFRTFromSubscriptPointer *makeDerivedFromBaseReturningFRTFromSubscriptPointer() {
     return new DerivedFromBaseReturningFRTFromSubscriptPointer();
 }
+
+struct IMMORTAL_FRT ImmortalBase {
+  int value = 0;
+
+  virtual int get42() const { return 42; }
+  virtual int getOverridden42() const { return 123; }
+  virtual int getIntValue() const { return value; }
+};
+
+struct IMMORTAL_FRT Immortal : public ImmortalBase {
+  static Immortal *_Nonnull create() { return new Immortal(); }
+
+  virtual int getOverridden42() const override { return 42; }
+  virtual void setIntValue(int newValue) { this->value = newValue; }
+};
+
+struct IMMORTAL_FRT DerivedFromImmortal : public Immortal {
+  static DerivedFromImmortal *_Nonnull create() {
+    return new DerivedFromImmortal();
+  }
+};
+
+struct HasDestructor {
+  ~HasDestructor() {}
+};
+
+struct IMMORTAL_FRT Immortal2 {
+public:
+  virtual void virtualMethod(HasDestructor) = 0;
+  virtual void virtualRename() const
+      __attribute__((swift_name("swiftVirtualRename()")));
+};
+
+inline const ImmortalBase *_Nonnull castToImmortalBase(
+    const Immortal *_Nonnull immortal) {
+  return static_cast<const ImmortalBase *>(immortal);
+}
+
+inline const Immortal *_Nonnull castToImmortal(
+    const DerivedFromImmortal *_Nonnull immortal) {
+  return static_cast<const Immortal *>(immortal);
+}
+
+//       A1
+//      /  \
+//     B1   B2
+//    /  \
+//  C1    C2
+
+struct IMMORTAL_FRT A1 {
+  virtual int virtualMethod() const { return 111; }
+
+  __attribute__((swift_name("swiftFooRename()"))) 
+  virtual int fooRename() const { return 112; }
+
+  __attribute__((swift_name("swiftBarRename()"))) 
+  virtual int barRename() const { return 113; }
+
+  __attribute__((swift_name("swiftParamsRename(a1:)"))) 
+  virtual int paramsRename(int i) const { return i; }
+
+  static A1 *_Nonnull create() { return new A1(); }
+};
+
+struct B1 : A1 {
+  __attribute__((swift_name("swiftVirtualMethod()")))
+  virtual int virtualMethod() const override { return 211; }
+
+  virtual int fooRename() const override { return 212; }
+  
+  __attribute__((swift_name("B1BarRename()"))) 
+  virtual int barRename() const override { return 213; }
+
+  __attribute__((swift_name("swiftParamsRename(b1:)"))) 
+  virtual int paramsRename(int i) const override { return i; }
+
+  static B1 *_Nonnull create() { return new B1(); }
+};
+
+struct B2 : A1 {
+  int virtualMethod() const { return 221; }
+
+  int fooRename() const { return 222; }
+
+  __attribute__((swift_name("B2BarRename()"))) 
+  int barRename() const {
+    return 223;
+  }
+
+  static B2 *_Nonnull create() { return new B2(); }
+};
+
+struct C1 : B1 {
+  __attribute__((swift_name("swiftFooRename()")))
+  virtual int fooRename() const override { return 312; }
+
+  __attribute__((swift_name("swiftBarRename()")))
+  virtual int barRename() const override { return 313; }
+
+  virtual int paramsRename(int i) const override { return i; }
+
+  static C1 *_Nonnull create() { return new C1(); }
+};
+
+struct C2 : B1 {
+  __attribute__((swift_name("swiftVirtualMethod()")))
+  virtual int virtualMethod() const override { return 321; }
+
+  __attribute__((swift_name("C2FooRename()")))
+  virtual int fooRename() const override { return 322; }
+
+  __attribute__((swift_name("B1BarRename()")))
+  virtual int barRename() const override { return 323; }
+
+  __attribute__((swift_name("swiftParamsRename(b1:)"))) 
+  virtual int paramsRename(int i) const override { return i; }
+
+  static C2 *_Nonnull create() { return new C2(); }
+};
+
+struct IMMORTAL_FRT A2 {
+  __attribute__((swift_name("swiftVirtualMethod()")))
+  virtual int virtualMethod() const { return 121; }
+
+  __attribute__((swift_name("swiftFooRename()")))
+  virtual int fooRename() const { return 122; }
+
+  __attribute__((swift_name("A2BarRename()"))) 
+  virtual int barRename() const { return 123; }
+
+  __attribute__((swift_name("swiftParamsRename(a2:)"))) virtual int
+  paramsRename(int i) const {
+    return i + 1;
+  }
+
+  static A2 *_Nonnull create() { return new A2(); }
+};
+
+//  A1    A2   
+//   \    /
+//     D1
+
+struct D1 : A1, A2 {
+  static D1 *_Nonnull create() { return new D1(); }
+};
+
+//  A1       A2   
+//   \       /
+//    B1    / 
+//      \  /
+//       D2
+
+struct D2 : B1, A2 {
+   __attribute__((swift_name("swiftVirtualMethod()")))
+  virtual int virtualMethod() const override { return 411; }
+
+  virtual int fooRename() const override { return 412; }
+  
+  virtual int barRename() const override { return 413; }
+
+  virtual int paramsRename(int i) const override { return i; }
+};
+
+//       A1
+//      /  \
+//     /    \
+//    B1    B2
+//    |\    /|
+//    | \  / |
+//    |  D3  |
+//    C1     |
+//     \     |
+//      \   /
+//        D4
+
+struct D3 : B1, B2 {};
+
+struct D4 : C1, B2 {};
+
+struct ValueType {
+  virtual int virtualMethod() const { return 111; }
+
+  __attribute__((swift_name("swiftRenameMethodBase()")))
+  virtual int renameMethodBase() const {
+    return 112;
+  }
+
+  virtual int renameMethodDerived() const { return 113; }
+
+  virtual int pureVirtualMethod() const = 0;
+
+  __attribute__((swift_name("swiftPureRenameBase()")))
+  virtual int pureRenameBase() const = 0;
+
+  virtual int pureRenameDerived() const = 0;
+};
+
+struct IMMORTAL_FRT DerivedFRTValueType : ValueType {
+  virtual int virtualMethod() const override { return 211; }
+
+  virtual int renameMethodBase() const override { return 212; }
+
+  __attribute__((swift_name("swiftRenameMethodDerived()")))
+  virtual int renameMethodDerived() const override {
+    return 213;
+  }
+
+  virtual int pureVirtualMethod() const override { return 214; }
+
+  virtual int pureRenameBase() const override { return 215; }
+
+  __attribute__((swift_name("swiftPureRenameDerived()"))) 
+  virtual int pureRenameDerived() const override {
+    return 216;
+  }
+
+  static DerivedFRTValueType *_Nonnull create() {
+    return new DerivedFRTValueType();
+  }
+};
+
+struct IMMORTAL_FRT EmptyDerivedFRTValueType : ValueType {};
+
+struct DerivedValueType : ValueType {
+  virtual int virtualMethod() const override { return 311; }
+
+  virtual int renameMethodBase() const override { return 312; }
+
+  __attribute__((swift_name("swiftRenameMethodDerived()"))) virtual int
+  renameMethodDerived() const override {
+    return 313;
+  }
+
+  virtual int pureVirtualMethod() const override { return 314; }
+
+  virtual int pureRenameBase() const override { return 315; }
+
+  __attribute__((swift_name("swiftPureRenameDerived()"))) virtual int
+  pureRenameDerived() const override {
+    return 316;
+  }
+};
+
+struct IMMORTAL_FRT AbstractFRT {
+  virtual int pureVirtualMethod() const = 0;
+
+  __attribute__((swift_name("swiftPureRenameBase()")))
+  virtual int pureRenameBase() const = 0;
+
+  virtual int pureRenameDerived() const = 0;
+};
+
+struct DerivedAbstractFRT : AbstractFRT {
+  virtual int pureVirtualMethod() const override { return 211; }
+
+  virtual int pureRenameBase() const override { return 212; }
+
+  __attribute__((swift_name("swiftPureRenameDerived()"))) 
+  virtual int pureRenameDerived() const override {
+    return 213;
+  }
+
+  static DerivedAbstractFRT *_Nonnull create() {
+    return new DerivedAbstractFRT();
+  }
+};
+
+struct EmptyDerivedAbstractFRT : AbstractFRT {};
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/module.modulemap b/test/Interop/Cxx/foreign-reference/Inputs/module.modulemap
index 847fa63a5f398..9fdc95f9599b5 100644
--- a/test/Interop/Cxx/foreign-reference/Inputs/module.modulemap
+++ b/test/Interop/Cxx/foreign-reference/Inputs/module.modulemap
@@ -35,7 +35,6 @@ module WitnessTable {
 
 module ReferenceCounted {
   header "reference-counted.h"
-  requires cplusplus
 }
 
 module ReferenceCountedObjCProperty {
@@ -44,6 +43,11 @@ module ReferenceCountedObjCProperty {
   export *
 }
 
+module LifetimeOperationMethods {
+  header "lifetime-operation-methods.h"
+  requires cplusplus
+}
+
 module MemberLayout {
   header "member-layout.h"
   requires cplusplus
@@ -63,3 +67,28 @@ module FunctionsAndMethodsReturningFRT {
   header "cxx-functions-and-methods-returning-frt.h"
   requires cplusplus
 }
+
+module PassAsParameter {
+  header "pass-as-parameter.h"
+  requires cplusplus
+}
+
+module Printed {
+  header "printed.h"
+  requires cplusplus
+}
+
+module VirtMethodWithRvalRef {
+  header "virtual-methods-with-rvalue-reference.h"
+  requires cplusplus
+}
+
+module LoggingFrts {
+    header "logging-frts.h"
+    requires cplusplus
+}
+
+module FRTReferenceReturns {
+  header "frt-reference-returns.h"
+  requires cplusplus
+}
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/pass-as-parameter.h b/test/Interop/Cxx/foreign-reference/Inputs/pass-as-parameter.h
new file mode 100644
index 0000000000000..b6375d354d034
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/Inputs/pass-as-parameter.h
@@ -0,0 +1,20 @@
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:immortal")))
+__attribute__((swift_attr("release:immortal"))) IntBox {
+  int value;
+  IntBox(int value) : value(value) {}
+
+  static IntBox *create(int value) { return new IntBox(value); }
+};
+
+inline int extractValueFromPtr(IntBox *b) { return b->value; }
+inline int extractValueFromRef(IntBox &b) { return b.value; }
+inline int extractValueFromConstRef(const IntBox &b) { return b.value; }
+inline int extractValueFromRefToPtr(IntBox *&b) { return b->value; }
+inline int extractValueFromRefToConstPtr(IntBox const *&b) { return b->value; }
+inline int extractValueFromConstRefToPtr(IntBox *const &b) { return b->value; }
+inline int extractValueFromConstRefToConstPtr(IntBox const *const &b) { return b->value; }
+
+inline void initializeByPtr(int value, IntBox **b) {
+  *b = IntBox::create(value);
+}
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/printed.h b/test/Interop/Cxx/foreign-reference/Inputs/printed.h
new file mode 100644
index 0000000000000..9f486cbdd3d52
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/Inputs/printed.h
@@ -0,0 +1,34 @@
+struct ImmortalFRT {
+private:
+  int priv = 1;
+  
+public:
+  int publ = 2;
+} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:immortal")))
+__attribute__((swift_attr("release:immortal")));
+
+struct FRTCustomStringConvertible {
+public:
+private:
+  int priv = 1;
+
+public:
+  int publ = 2;
+} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:immortal")))
+__attribute__((swift_attr("release:immortal")));
+
+struct FRType {
+private:
+  int priv = 1;
+
+public:
+  int publ = 2;
+} __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retain")))
+__attribute__((swift_attr("release:release")));
+
+void retain(FRType *v) {};
+void release(FRType *v) {};
+
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/reference-counted.h b/test/Interop/Cxx/foreign-reference/Inputs/reference-counted.h
index 1ed4c3512d8d5..bfdca75590fa1 100644
--- a/test/Interop/Cxx/foreign-reference/Inputs/reference-counted.h
+++ b/test/Interop/Cxx/foreign-reference/Inputs/reference-counted.h
@@ -2,7 +2,10 @@
 #define TEST_INTEROP_CXX_FOREIGN_REFERENCE_INPUTS_REFERENCE_COUNTED_H
 
 #include <stdlib.h>
+
+#ifdef __cplusplus
 #include <new>
+#endif
 
 #include "visibility.h"
 
@@ -10,6 +13,8 @@ SWIFT_BEGIN_NULLABILITY_ANNOTATIONS
 
 static int finalLocalRefCount = 100;
 
+#ifdef __cplusplus
+
 namespace NS {
 
 struct __attribute__((swift_attr("import_as_ref")))
@@ -64,6 +69,45 @@ GlobalCountNullableInit {
 inline void GCRetainNullableInit(GlobalCountNullableInit *x) { globalCount++; }
 inline void GCReleaseNullableInit(GlobalCountNullableInit *x) { globalCount--; }
 
+struct __attribute__((swift_attr("import_as_ref")))
+__attribute__((swift_attr("retain:RCRetain")))
+__attribute__((swift_attr("release:RCRelease"))) HasOpsReturningRefCount final {
+  int refCount = 0;
+
+  static HasOpsReturningRefCount *create() {
+    return new (malloc(sizeof(HasOpsReturningRefCount)))
+        HasOpsReturningRefCount();
+  }
+};
+
+inline unsigned RCRetain(HasOpsReturningRefCount *x) { return ++x->refCount; }
+inline unsigned RCRelease(HasOpsReturningRefCount *x) { return --x->refCount; }
+
+#endif
+
+typedef struct __attribute__((swift_attr("import_as_ref")))
+__attribute__((swift_attr("retain:INRetain")))
+__attribute__((swift_attr("release:INRelease"))) IncompleteImpl *Incomplete;
+
+typedef struct OpaqueRefImpl *OpaqueRef;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+Incomplete Incomplete_create(double weight) __attribute__((swift_attr("returns_retained"))) __attribute__((swift_name("IncompleteImpl.init(weight:)")));
+void INRetain(Incomplete i);
+void INRelease(Incomplete i);
+double Incomplete_getWeight(Incomplete i) __attribute__((swift_name("getter:IncompleteImpl.weight(self:)")));
+
+OpaqueRef Opaque_create(void);
+void OPRetain(OpaqueRef i);
+void OPRelease(OpaqueRef i);
+
+#ifdef __cplusplus
+}
+#endif
+
 SWIFT_END_NULLABILITY_ANNOTATIONS
 
 #endif // TEST_INTEROP_CXX_FOREIGN_REFERENCE_INPUTS_REFERENCE_COUNTED_H
diff --git a/test/Interop/Cxx/foreign-reference/Inputs/virtual-methods-with-rvalue-reference.h b/test/Interop/Cxx/foreign-reference/Inputs/virtual-methods-with-rvalue-reference.h
new file mode 100644
index 0000000000000..aa8a46a48d1a4
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/Inputs/virtual-methods-with-rvalue-reference.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include "swift/bridging"
+
+class CxxForeignRef;
+
+void retain(CxxForeignRef * obj);
+void release(CxxForeignRef * obj);
+
+struct NonTrivial {
+  NonTrivial(const NonTrivial &other);
+  ~NonTrivial();
+};
+
+class CxxForeignRef {
+public:
+  CxxForeignRef(const CxxForeignRef &) = delete;
+  CxxForeignRef() = default;
+
+  virtual void takesRValRef(NonTrivial &&);
+} SWIFT_SHARED_REFERENCE(retain, release);
+
diff --git a/test/Interop/Cxx/foreign-reference/array-of-classes.swift b/test/Interop/Cxx/foreign-reference/array-of-classes.swift
new file mode 100644
index 0000000000000..17f135971f49c
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/array-of-classes.swift
@@ -0,0 +1,73 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %swiftc_driver -O -I %t/Inputs  %t/test.swift -cxx-interoperability-mode=default -I %swift_src_root/lib/ClangImporter/SwiftBridging -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: OS=macosx || OS=linux-gnu
+// REQUIRES: executable_test
+// UNSUPPORTED: back_deployment_runtime
+
+//--- Inputs/module.modulemap
+
+module Test {
+    header "reftype.h"
+    requires cplusplus
+}
+
+//--- Inputs/reftype.h
+
+#include "swift/bridging"
+
+class RefType {
+public:
+    static RefType* _Nonnull makeRefType() SWIFT_RETURNS_RETAINED {
+        return new RefType();
+    }
+
+private:
+    RefType() : _refCount(1) {
+    }
+    RefType(const RefType&) = delete;
+    RefType& operator=(const RefType&) = delete;
+    ~RefType() {
+    }
+    
+    inline friend void retainRefType(RefType* _Nonnull x) {
+        x->_refCount += 1;
+
+    }
+    inline friend void releaseRefType(RefType* _Nonnull x) {
+        x->_refCount -= 1;
+        if (x->_refCount == 0) {
+            delete x;
+        }
+    }
+    
+    int _refCount;
+} SWIFT_SHARED_REFERENCE(retainRefType, releaseRefType);
+
+//--- test.swift
+
+import Test
+
+@inline(never)
+func go() {
+    let x: RefType = RefType.makeRefType()
+    var y: [RefType] = []
+    y.append(x)
+// CHECK: 1
+    print(y.count)
+
+    var loopCount = 0 
+    for it in y {
+// CHECK: RefType()
+        print(it)
+        loopCount += 1
+    }
+// CHECK: 1
+    print(loopCount)
+}
+
+go()
+
diff --git a/test/Interop/Cxx/foreign-reference/base-class-layout-irgen.swift b/test/Interop/Cxx/foreign-reference/base-class-layout-irgen.swift
index cfbda03cb9b2b..8866fb5db666e 100644
--- a/test/Interop/Cxx/foreign-reference/base-class-layout-irgen.swift
+++ b/test/Interop/Cxx/foreign-reference/base-class-layout-irgen.swift
@@ -5,7 +5,7 @@ import MemberLayout
 // CHECK: %TSo7IntBaseV = type <{ [4 x i8], %Ts5Int32V }>
 
 // CHECK-LABEL: define {{.*}}swiftcc i32 @"$s4testAA1ys5Int32VSo7IntBaseV_tF"(ptr %0)
-// CHECK: getelementptr inbounds %TSo7IntBaseV, ptr %0, i32 0, i32 1
+// CHECK: getelementptr inbounds{{.*}} %TSo7IntBaseV, ptr %0, i32 0, i32 1
 public func test(y: IntBase) -> CInt {
   return y.i
 }
diff --git a/test/Interop/Cxx/foreign-reference/cxx-frt-ctor-callable.swift b/test/Interop/Cxx/foreign-reference/cxx-frt-ctor-callable.swift
new file mode 100644
index 0000000000000..a90f4f28f3618
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/cxx-frt-ctor-callable.swift
@@ -0,0 +1,24 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -typecheck -verify -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop -disable-availability-checking
+
+//--- Inputs/module.modulemap
+module Test {
+    header "test.h"
+    requires cplusplus
+}
+
+//--- Inputs/test.h
+struct
+    __attribute__((swift_attr("import_reference")))
+    __attribute__((swift_attr("retain:immortal")))
+    __attribute__((swift_attr("release:immortal")))
+HasCtor {
+  HasCtor(int a) {}
+};
+
+//--- test.swift
+
+import Test
+
+let x = HasCtor(42)
diff --git a/test/Interop/Cxx/foreign-reference/derived-field-getter-retainable-frt-irgen.swift b/test/Interop/Cxx/foreign-reference/derived-field-getter-retainable-frt-irgen.swift
index a8eb643102929..aeacbd09db366 100644
--- a/test/Interop/Cxx/foreign-reference/derived-field-getter-retainable-frt-irgen.swift
+++ b/test/Interop/Cxx/foreign-reference/derived-field-getter-retainable-frt-irgen.swift
@@ -11,6 +11,6 @@ let _ = testGetX()
 
 
 // CHECK: define {{.*}}linkonce_odr{{.*}} ptr @{{.*}}__synthesizedBaseGetterAccessor_{{.*}}(ptr {{.*}} %[[THIS_PTR:.*]])
-// CHECK: %[[VALUE_PTR_PTR:.*]] = getelementptr inbounds %class.BaseFieldFRT, ptr %{{.*}}, i32 0, i32 0
+// CHECK: %[[VALUE_PTR_PTR:.*]] = getelementptr inbounds{{.*}} %class.BaseFieldFRT, ptr %{{.*}}, i32 0, i32 0
 // CHECK: %[[VALUE_PTR:.*]] = load ptr, ptr %[[VALUE_PTR_PTR]]
 // CHECK: call void @{{.*}}retainRefCounted{{.*}}(ptr noundef %[[VALUE_PTR]])
diff --git a/test/Interop/Cxx/foreign-reference/extensions.swift b/test/Interop/Cxx/foreign-reference/extensions.swift
index 818b648be3981..b726bea691e54 100644
--- a/test/Interop/Cxx/foreign-reference/extensions.swift
+++ b/test/Interop/Cxx/foreign-reference/extensions.swift
@@ -1,9 +1,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -cxx-interoperability-mode=default -Xfrontend -disable-availability-checking -Onone) | %FileCheck %s
 // REQUIRES: executable_test
 
-// Metadata for foreign reference types is not supported on Windows.
-// UNSUPPORTED: OS=windows-msvc
-
 import ReferenceCounted
 
 protocol MyProto {
diff --git a/test/Interop/Cxx/foreign-reference/frt-reference-returns-diagnostics.swift b/test/Interop/Cxx/foreign-reference/frt-reference-returns-diagnostics.swift
new file mode 100644
index 0000000000000..7f974ab2c1a23
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/frt-reference-returns-diagnostics.swift
@@ -0,0 +1,31 @@
+// RUN: rm -rf %t
+// RUN: %target-typecheck-verify-swift -I %S%{fs-sep}Inputs -cxx-interoperability-mode=default -enable-experimental-feature WarnUnannotatedReturnOfCxxFrt -verify-additional-file %S%{fs-sep}Inputs%{fs-sep}frt-reference-returns.h
+
+// REQUIRES: swift_feature_WarnUnannotatedReturnOfCxxFrt
+
+import FRTReferenceReturns
+
+func testNoAnnotations() {
+  let _ = NoAnnotations.getRefCountedByRef()
+  // expected-warning@-1 {{cannot infer the ownership of the returned value, annotate 'getRefCountedByRef()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+  let _ = NoAnnotations.createRefCountedByRef()
+  // expected-warning@-1 {{cannot infer the ownership of the returned value, annotate 'createRefCountedByRef()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+  let _ = NoAnnotations.copyRefCountedByRef()
+  // expected-warning@-1 {{cannot infer the ownership of the returned value, annotate 'copyRefCountedByRef()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+}
+
+func testAPIAnnotations() {
+  let _ = APIAnnotations.createByRef()
+  let _ = APIAnnotations.getByRef()
+}
+
+func testTypeAnnotation() {
+  let _ = TypeAnnotation.getByRef()
+  let _ = TypeAnnotation.createByRef()
+  let _ = TypeAnnotation.copyByRef()
+}
+
+func testBothAnnotations() {
+  let _ = BothAnnotations.createByRef() 
+  let _ = BothAnnotations.getByRef()
+}
diff --git a/test/Interop/Cxx/foreign-reference/frt-reference-returns-sil.swift b/test/Interop/Cxx/foreign-reference/frt-reference-returns-sil.swift
new file mode 100644
index 0000000000000..fb02159e5fb18
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/frt-reference-returns-sil.swift
@@ -0,0 +1,35 @@
+// RUN: %target-swift-emit-sil -I %S/Inputs -cxx-interoperability-mode=default -disable-availability-checking -diagnostic-style llvm %s -validate-tbd-against-ir=none -Xcc -fignore-exceptions | %FileCheck %s
+
+import FRTReferenceReturns
+
+// Test that the ownership annotations work correctly for reference returns
+
+func useAll() {
+  let _ = NoAnnotations.getRefCountedByRef()
+  // CHECK: sil [clang NoAnnotations.getRefCountedByRef] @{{.*}} : $@convention(c) () -> NoAnnotations.RefCountedType
+  // Note: create/copy rule (default without ownership annotations) does not apply if return type is & to frt
+  let _ = NoAnnotations.createRefCountedByRef()
+  // CHECK: sil [clang NoAnnotations.createRefCountedByRef] @{{.*}} : $@convention(c) () -> NoAnnotations.RefCountedType
+  let _ = NoAnnotations.copyRefCountedByRef()
+  // CHECK: sil [clang NoAnnotations.copyRefCountedByRef] @{{.*}} : $@convention(c) () -> NoAnnotations.RefCountedType
+
+  // APIAnnotations - explicit ownership
+  let _ = APIAnnotations.createByRef()
+  // CHECK: sil [clang APIAnnotations.createByRef] @{{.*}} : $@convention(c) () -> @owned APIAnnotations.RefCountedType
+  let _ = APIAnnotations.getByRef()
+  // CHECK: sil [clang APIAnnotations.getByRef] @{{.*}} : $@convention(c) () -> APIAnnotations.RefCountedType
+
+  // TypeAnnotation - all unretained due to type default
+  let _ = TypeAnnotation.getByRef()
+  // CHECK: sil [clang TypeAnnotation.getByRef] @{{.*}} : $@convention(c) () -> TypeAnnotation.RefCountedType
+  let _ = TypeAnnotation.createByRef()
+  // CHECK: sil [clang TypeAnnotation.createByRef] @{{.*}} : $@convention(c) () -> TypeAnnotation.RefCountedType
+  let _ = TypeAnnotation.copyByRef()
+  // CHECK: sil [clang TypeAnnotation.copyByRef] @{{.*}} : $@convention(c) () -> TypeAnnotation.RefCountedType
+
+  // BothAnnotations - API overrides type
+  let _ = BothAnnotations.createByRef()
+  // CHECK: sil [clang BothAnnotations.createByRef] @{{.*}} : $@convention(c) () -> @owned BothAnnotations.RefCountedType
+  let _ = BothAnnotations.getByRef()
+  // CHECK: sil [clang BothAnnotations.getByRef] @{{.*}} : $@convention(c) () -> BothAnnotations.RefCountedType
+}
diff --git a/test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes-error.swift b/test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes-error.swift
index 7e93d6fcfe1da..4bc5eaf434cc8 100644
--- a/test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes-error.swift
+++ b/test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes-error.swift
@@ -1,55 +1,54 @@
 // RUN: rm -rf %t
-// RUN: not %target-swift-frontend -typecheck -I %S/Inputs  %s -cxx-interoperability-mode=upcoming-swift 2>&1 | %FileCheck %s
+// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs  %s -cxx-interoperability-mode=upcoming-swift -enable-experimental-feature WarnUnannotatedReturnOfCxxFrt -verify-additional-file %S/Inputs/cxx-functions-and-methods-returning-frt.h -Xcc -Wno-return-type -Xcc -Wno-nullability-completeness
+
+// XFAIL: OS=windows-msvc
+// TODO: Enable this on windows when -verify-additional-file issue on Windows Swift CI is resolved 
+
+// REQUIRES: swift_feature_WarnUnannotatedReturnOfCxxFrt
 
 import FunctionsAndMethodsReturningFRT
 import CxxStdlib
 
 let frtLocalVar1 = global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained()
-// CHECK: error: 'global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained' cannot be annotated with both SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED
-
 let frtLocalVar2 = StructWithStaticMethodsReturningFRTWithBothAttributesReturnsRetainedAndReturnsUnretained.StaticMethodReturningFRT()
-// CHECK: error: 'StaticMethodReturningFRT' cannot be annotated with both SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED
-let frtLocalVar3 = StructWithAPIsReturningCxxFrt.StaticMethodReturningCxxFrt()
-// CHECK: warning: 'StaticMethodReturningCxxFrt' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
+let frtLocalVar3 = StructWithAPIsReturningCxxFrt.StaticMethodReturningCxxFrt() // expected-warning {{cannot infer the ownership of the returned value, annotate 'StaticMethodReturningCxxFrt()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 let frtLocalVar4 = StructWithAPIsReturningCxxFrt.StaticMethodReturningCxxFrtWithAnnotation()
-
-let frtLocalVar5 = global_function_returning_cxx_frt()
-// CHECK: warning: 'global_function_returning_cxx_frt' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
+let frtLocalVar5 = global_function_returning_cxx_frt() // expected-warning {{cannot infer the ownership of the returned value, annotate 'global_function_returning_cxx_frt()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 let frtLocalVar6 = global_function_returning_cxx_frt_with_annotations()
-
 let frtLocalVar7 = StructWithAPIsReturningNonCxxFrt.StaticMethodReturningNonCxxFrt()
 let frtLocalVar8 = StructWithAPIsReturningNonCxxFrt.StaticMethodReturningNonCxxFrtWithAnnotation()
-// CHECK: error: 'StaticMethodReturningNonCxxFrtWithAnnotation' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
 let frtLocalVar9 = global_function_returning_non_cxx_frt()
 let frtLocalVar10 = global_function_returning_non_cxx_frt_with_annotations()
-// CHECK: error: 'global_function_returning_non_cxx_frt_with_annotations' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
 let frtLocalVar11 = StructWithAPIsReturningImmortalReference.StaticMethodReturningImmortalReference()
 let frtLocalVar12 = StructWithAPIsReturningImmortalReference.StaticMethodReturningImmortalReferenceWithAnnotation()
-// CHECK: error: 'StaticMethodReturningImmortalReferenceWithAnnotation' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
 let frtLocalVar13 = global_function_returning_immortal_reference()
 let frtLocalVar14 = global_function_returning_immortal_reference_with_annotations()
-// CHECK: error: 'global_function_returning_immortal_reference_with_annotations' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
-let frtLocalVar15 = StructWithAPIsReturningUnsafeReference.StaticMethodReturningUnsafeReference()
 let frtLocalVar16 = StructWithAPIsReturningUnsafeReference.StaticMethodReturningUnsafeReferenceWithAnnotation()
-// CHECK: error: 'StaticMethodReturningUnsafeReferenceWithAnnotation' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
 let frtLocalVar17 = global_function_returning_unsafe_reference()
 let frtLocalVar18 = global_function_returning_unsafe_reference_with_annotations()
-// CHECK: error: 'global_function_returning_unsafe_reference_with_annotations' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
-let x = returnFRTOverloadedOperators()
-// CHECK: warning: 'returnFRTOverloadedOperators' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
-let y = returnFRTOverloadedOperators()
-// CHECK: warning: 'returnFRTOverloadedOperators' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
+let x = returnFRTOverloadedOperators() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnFRTOverloadedOperators()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+let y = returnFRTOverloadedOperators() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnFRTOverloadedOperators()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 let z = x + y
-// CHECK: warning: SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED is not supported yet for overloaded C++ 'operator+'. Overloaded C++ operators always return SWIFT_SHARED_REFERENCE types as owned
 let w = x - y
-// CHECK-NOT: warning: 'operator-' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
-
 let f = FunctionVoidToFRTStruct()
 let frt = f()
-// CHECK-NOT: warning: 'operator()' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
+let nonFrt = NonFRTStruct()
+let nonFrtLocalVar1 = global_function_returning_templated_retrun_frt_owned(nonFrt)
+let _ = DefaultOwnershipConventionOnCXXForeignRefType.returnRefTyDefUnretained()
+let _ = FunctionAnnotationHasPrecedence.returnRefTyDefUnretained()
+let _ = FunctionAnnotationHasPrecedence.returnRefTyDefUnretainedAnnotatedRetained()
+let _ = DefaultOwnershipSuppressUnannotatedAPIWarning.returnRefType() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnRefType()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+let _ = DefaultOwnershipSuppressUnannotatedAPIWarning.returnRefTyDefUnretainedd()
+let _ = DefaultOwnershipInheritance.createBaseType()
+let _ = DefaultOwnershipInheritance.createDerivedType()
+let _ = DefaultOwnershipInheritance.createDerivedType2()
+let _ = DefaultOwnershipInheritance.createBaseTypeNonDefault() // expected-warning {{cannot infer the ownership of the returned value, annotate 'createBaseTypeNonDefault()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+let _ = DefaultOwnershipInheritance.createDerivedTypeNonDefault() // expected-warning {{cannot infer the ownership of the returned value, annotate 'createDerivedTypeNonDefault()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+let _ = DefaultOwnershipInheritance.createDerivedTypeNonDefaultUnretained()
+let  _ = SourceLocationCaching.FactoryA.make() // expected-warning {{cannot infer the ownership of the returned value, annotate 'make()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+let  _ = SourceLocationCaching.FactoryB.make() // expected-warning {{cannot infer the ownership of the returned value, annotate 'make()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+
+let refTemplate = FRTStructRef()
+let templatePtr = refTemplate.ptr()
+let templateGet = refTemplate.get()
+let templateValue = refTemplate.value()  // expected-warning {{cannot infer the ownership of the returned value, annotate 'value()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
diff --git a/test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes.swift b/test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes.swift
index ecda6254fc2b6..00df0fa9a5a01 100644
--- a/test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes.swift
+++ b/test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes.swift
@@ -185,7 +185,7 @@ func testStaticMethodsReturningNonFRT() {
     // CHECK: function_ref @{{.*}}StaticMethodReturningNonFRT_copy{{.*}} : $@convention(c) () -> UnsafeMutablePointer<NonFRTStruct> 
 }
 
-func testtFreeFunctionsTemplated(frt : FRTStruct) {
+func testtFreeFunctionsTemplated(frt : FRTStruct, nonFrt: NonFRTStruct) {
     let frtLocalVar1 : Int = 1;
     
     let frtLocalVar2 = global_templated_function_returning_FRT(frtLocalVar1)
@@ -227,6 +227,8 @@ func testtFreeFunctionsTemplated(frt : FRTStruct) {
     let frtLocalVar14 = global_function_returning_templated_retrun_frt_owned(frt)
     // CHECK: function_ref @{{.*}}global_function_returning_templated_retrun_frt_owned{{.*}} : $@convention(c) (FRTStruct) -> @owned FRTStruct
 
+    let nonFrtLocalVar1 = global_function_returning_templated_retrun_frt_owned(nonFrt)
+    // CHECK: function_ref @{{.*}}global_function_returning_templated_retrun_frt_owned{{.*}} : $@convention(c) (NonFRTStruct) -> NonFRTStruct
 }
 
 func testVirtualMethods(base: Base, derived: Derived) {
@@ -245,3 +247,45 @@ func testVirtualMethods(base: Base, derived: Derived) {
     var frt4 = mutableDerived.VirtualMethodReturningFRTOwned()
     // CHECK: function_ref @{{.*}}VirtualMethodReturningFRTOwned{{.*}} : $@convention(cxx_method) (@inout Derived) -> @owned FRTStruct
 }
+
+func testDefaultOwnershipAnnotation() {
+  let _ = DefaultOwnershipConventionOnCXXForeignRefType.returnRefTyDefUnretained()
+  // CHECK: function_ref {{.*}}returnRefTyDefUnretained{{.*}} : $@convention(c) () -> DefaultOwnershipConventionOnCXXForeignRefType.RefTyDefUnretained
+
+  let _ = FunctionAnnotationHasPrecedence.returnRefTyDefUnretained()
+  // CHECK: function_ref {{.*}}returnRefTyDefUnretained{{.*}} : $@convention(c) () -> FunctionAnnotationHasPrecedence.RefTyDefUnretained
+
+  let _ = FunctionAnnotationHasPrecedence.returnRefTyDefUnretainedAnnotatedRetained()
+  // CHECK: function_ref {{.*}}returnRefTyDefUnretainedAnnotatedRetained{{.*}} : $@convention(c) () -> @owned FunctionAnnotationHasPrecedence.RefTyDefUnretained
+
+  let _ = DefaultOwnershipInheritance.createBaseType()
+  // CHECK: function_ref {{.*}}createBaseType{{.*}} : $@convention(c) () -> DefaultOwnershipInheritance.BaseType
+
+  let _ = DefaultOwnershipInheritance.createDerivedType()
+  // CHECK: function_ref {{.*}}createDerivedType{{.*}} : $@convention(c) () -> DefaultOwnershipInheritance.DerivedType
+
+  let _ = DefaultOwnershipInheritance.createDerivedType2()
+  // CHECK: function_ref {{.*}}createDerivedType2{{.*}} : $@convention(c) () -> DefaultOwnershipInheritance.DerivedType2
+
+  let _ = DefaultOwnershipInheritance.createBaseTypeNonDefault()
+  // CHECK: function_ref {{.*}}createBaseTypeNonDefault{{.*}} : $@convention(c) () -> @owned DefaultOwnershipInheritance.BaseTypeNonDefault
+
+  let _ = DefaultOwnershipInheritance.createDerivedTypeNonDefault()
+  // CHECK: function_ref {{.*}}createDerivedTypeNonDefault{{.*}} : $@convention(c) () -> @owned DefaultOwnershipInheritance.DerivedTypeNonDefault
+
+  let _ = DefaultOwnershipInheritance.createDerivedTypeNonDefaultUnretained()
+  // CHECK: function_ref {{.*}}createDerivedTypeNonDefaultUnretained{{.*}} : $@convention(c) () -> DefaultOwnershipInheritance.DerivedTypeNonDefault
+}
+
+func testTemplateMemberFunctions() {
+  let refTemplate = FRTStructRef()
+
+  let ptr = refTemplate.ptr()
+  // CHECK: function_ref {{.*}}ptr{{.*}} : $@convention(cxx_method) (@in_guaranteed RefTemplate<FRTStruct>) -> @owned FRTStruct
+
+  let get = refTemplate.get()
+  // CHECK: function_ref {{.*}}get{{.*}} : $@convention(cxx_method) (@in_guaranteed RefTemplate<FRTStruct>) -> FRTStruct
+
+  let value = refTemplate.value()
+  // CHECK: function_ref {{.*}}value{{.*}} : $@convention(cxx_method) (@in_guaranteed RefTemplate<FRTStruct>) -> FRTStruct
+}
diff --git a/test/Interop/Cxx/foreign-reference/frts-as-fields.swift b/test/Interop/Cxx/foreign-reference/frts-as-fields.swift
new file mode 100644
index 0000000000000..6bb4609bcfbe2
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/frts-as-fields.swift
@@ -0,0 +1,52 @@
+// RUN: %target-run-simple-swift(-I %swift_src_root/lib/ClangImporter/SwiftBridging -I %S/Inputs -cxx-interoperability-mode=default -Xfrontend -disable-availability-checking -Onone) | %FileCheck %s
+
+// REQUIRES: executable_test
+
+import LoggingFrts
+
+struct SwiftStruct {
+    var frt: SharedFRT
+    var token: MyToken
+}
+
+func go() {
+    let frt = SharedFRT()
+    let token = MyToken()
+    let _ = SwiftStruct(frt: frt, token: token)
+    let _ = SwiftStruct(frt: frt, token: token)
+    let _ = SwiftStruct(frt: frt, token: token)
+}
+
+go()
+
+// CHECK:      RefCount: 1, message: Ctor
+// CHECK-NEXT: RefCount: 2, message: retain
+// CHECK-NEXT: RefCount: 1, message: release
+// CHECK-NEXT: RefCount: 2, message: retain
+// CHECK-NEXT: RefCount: 1, message: release
+// CHECK-NEXT: RefCount: 2, message: retain
+// CHECK-NEXT: RefCount: 1, message: release
+// CHECK-NEXT: RefCount: 0, message: release
+// CHECK-NEXT: RefCount: 0, message: Dtor
+
+func takesLargeStructWithRefCountedField(_ x: LargeStructWithRefCountedField) {
+    var a = x
+}
+
+takesLargeStructWithRefCountedField(getStruct())
+// CHECK:      RefCount: 1, message: Ctor
+// CHECK-NEXT: RefCount: 2, message: retain
+// CHECK-NEXT: RefCount: 1, message: release
+// CHECK-NEXT: RefCount: 0, message: release
+// CHECK-NEXT: RefCount: 0, message: Dtor
+
+func takesLargeStructWithRefCountedFieldNested(_ x: LargeStructWithRefCountedFieldNested) {
+    var a = x
+}
+
+takesLargeStructWithRefCountedFieldNested(getNestedStruct())
+// CHECK:      RefCount: 1, message: Ctor
+// CHECK-NEXT: RefCount: 2, message: retain
+// CHECK-NEXT: RefCount: 1, message: release
+// CHECK-NEXT: RefCount: 0, message: release
+// CHECK-NEXT: RefCount: 0, message: Dtor
diff --git a/test/Interop/Cxx/foreign-reference/get-frt-from-smart-ptr.swift b/test/Interop/Cxx/foreign-reference/get-frt-from-smart-ptr.swift
new file mode 100644
index 0000000000000..3020e8fd55d91
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/get-frt-from-smart-ptr.swift
@@ -0,0 +1,26 @@
+// RUN: %target-run-simple-swift(-I %swift_src_root/lib/ClangImporter/SwiftBridging -I %S/Inputs -cxx-interoperability-mode=default -Xfrontend -disable-availability-checking -O) | %FileCheck %s
+
+// REQUIRES: executable_test
+
+import LoggingFrts
+
+@inline(never)
+func use(_ x: CInt) {
+    print("Value is \(x).")
+}
+
+func testRefIssues() {
+    var a2 = Optional.some(Payload.create(0));
+    let b2 = a2!.ptr();
+    a2 = Optional.none;
+    let v2 = b2.value();
+    use(v2)
+}
+testRefIssues()
+
+// CHECK:      RefCount: 1, message: Ctor
+// CHECK-NEXT: RefCount: 2, message: retain
+// CHECK-NEXT: RefCount: 1, message: release
+// CHECK-NEXT: Value is 0.
+// CHECK-NEXT: RefCount: 0, message: release
+// CHECK-NEXT: RefCount: 0, message: Dtor
diff --git a/test/Interop/Cxx/foreign-reference/incomplete.swift b/test/Interop/Cxx/foreign-reference/incomplete.swift
new file mode 100644
index 0000000000000..de679b35619ce
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/incomplete.swift
@@ -0,0 +1,47 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-clang -x c -c %S/Inputs/incomplete.c -I %S/Inputs -o %t/incomplete-c.o
+
+// Build with C interoperatibility
+// RUN: %target-build-swift %s -I %S/Inputs -o %t/incomplete %t/incomplete-c.o
+// RUN: %target-codesign %t/incomplete
+// RUN: %target-run %t/incomplete | %FileCheck %s
+
+// Build with C++ interoperability
+// RUN: %target-build-swift %s -I %S/Inputs -o %t/incomplete %t/incomplete-c.o -Xfrontend -cxx-interoperability-mode=default
+// RUN: %target-codesign %t/incomplete
+// RUN: %target-run %t/incomplete | %FileCheck %s
+
+// REQUIRES: executable_test
+
+import ReferenceCounted
+
+func testIncomplete() {
+  do {
+    let i = Incomplete(weight: 3.14159)
+    // CHECK: Incomplete weight = 3.14159
+    print("Incomplete weight = \(i.weight)")
+
+    // Instance destroyed at the end
+  }
+
+  // CHECK: Destroyed instance containing weight 3.14159
+}
+
+func testOpaqueRef() {
+  // CHECK: Creating OpaqueRef
+  print("Creating OpaqueRef")
+  let opaque = Opaque_create()
+  let opaque2 = opaque
+  _ = opaque
+  _ = opaque2
+  // let it go out of scope
+
+  // CHECK: Destroyed OpaqueRef instance
+  // CHECK-NOT: Destroyed OpaqueRef instance
+}
+
+testIncomplete()
+testOpaqueRef()
+
+// CHECK: DONE
+print("DONE")
diff --git a/test/Interop/Cxx/foreign-reference/inheritance-diagnostics.swift b/test/Interop/Cxx/foreign-reference/inheritance-diagnostics.swift
index 1e0047d3ea855..563b377b2c474 100644
--- a/test/Interop/Cxx/foreign-reference/inheritance-diagnostics.swift
+++ b/test/Interop/Cxx/foreign-reference/inheritance-diagnostics.swift
@@ -1,40 +1,39 @@
 // RUN: rm -rf %t
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs  %s -cxx-interoperability-mode=upcoming-swift -verify-additional-file %S/Inputs/inheritance.h -Xcc -Wno-return-type -Xcc -Wno-inaccessible-base
+// RUN: %target-swift-frontend -typecheck -verify -I %S%{fs-sep}Inputs  %s -cxx-interoperability-mode=upcoming-swift -enable-experimental-feature WarnUnannotatedReturnOfCxxFrt -verify-additional-file %S%{fs-sep}Inputs%{fs-sep}inheritance.h -Xcc -Wno-return-type -Xcc -Wno-inaccessible-base
 
-// TODO: Fix this lit test failure on windows rdar://145218056
-// XFAIL: OS=windows-msvc
+// REQUIRES: swift_feature_WarnUnannotatedReturnOfCxxFrt
 
 import Inheritance
 
 let _ = ImmortalRefereceExample.returnImmortalRefType()
-let _ = ImmortalRefereceExample.returnDerivedFromImmortalRefType()
+let _ = ImmortalRefereceExample.returnDerivedFromImmortalRefType() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnDerivedFromImmortalRefType()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 
 let _ = ExplicitAnnotationHasPrecedence1.returnValueType()
-let _ = ExplicitAnnotationHasPrecedence1.returnRefType()
+let _ = ExplicitAnnotationHasPrecedence1.returnRefType() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnRefType()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 let _ = ExplicitAnnotationHasPrecedence1.returnDerivedFromValueType()
-let _ = ExplicitAnnotationHasPrecedence1.returnDerivedFromValueTypeAndAnnotated()
-let _ = ExplicitAnnotationHasPrecedence1.returnDerivedFromRefType()
-let _ = ExplicitAnnotationHasPrecedence1.returnDerivedFromRefTypeAndAnnotated()
+let _ = ExplicitAnnotationHasPrecedence1.returnDerivedFromValueTypeAndAnnotated() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnDerivedFromValueTypeAndAnnotated()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+let _ = ExplicitAnnotationHasPrecedence1.returnDerivedFromRefType() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnDerivedFromRefType()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+let _ = ExplicitAnnotationHasPrecedence1.returnDerivedFromRefTypeAndAnnotated() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnDerivedFromRefTypeAndAnnotated()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 
 let _ = ExplicitAnnotationHasPrecedence2.returnDerivedFromRefTypeAAndB()
-let _ = ExplicitAnnotationHasPrecedence2.returnDerivedFromRefTypeAAndBAnnotated()
+let _ = ExplicitAnnotationHasPrecedence2.returnDerivedFromRefTypeAAndBAnnotated() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnDerivedFromRefTypeAAndBAnnotated()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 
 let _ = BasicInheritanceExample.returnValueType()
-let _ = BasicInheritanceExample.returnRefType()
-let _ = BasicInheritanceExample.returnDerivedFromRefType()
+let _ = BasicInheritanceExample.returnRefType() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnRefType()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
+let _ = BasicInheritanceExample.returnDerivedFromRefType() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnDerivedFromRefType()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 
 let _ = MultipleInheritanceExample1.returnDerivedFromBaseRef1AndBaseRef2()
-let _ = MultipleInheritanceExample1.returnDerivedFromBaseRef3()
+let _ = MultipleInheritanceExample1.returnDerivedFromBaseRef3() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnDerivedFromBaseRef3()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 
 let _ = MultipleInheritanceExample2.returnD()
 
 let _ = MultipleInheritanceExample3.returnD()
 
-let _ = OverloadedRetainRelease.returnD()
+let _ = OverloadedRetainRelease.returnD() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnD()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 
 let _ = RefTypeDiamondInheritance.returnDiamond()
-let _ = RefTypeDiamondInheritance.returnVirtualDiamond()
+let _ = RefTypeDiamondInheritance.returnVirtualDiamond() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnVirtualDiamond()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 
-let _ = NonRefTypeDiamondInheritance.returnDiamond()
+let _ = NonRefTypeDiamondInheritance.returnDiamond() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnDiamond()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 
-let _ = InheritingTemplatedRefType.returnForest()
+let _ = InheritingTemplatedRefType.returnForest() // expected-warning {{cannot infer the ownership of the returned value, annotate 'returnForest()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
diff --git a/test/Interop/Cxx/foreign-reference/inheritance.swift b/test/Interop/Cxx/foreign-reference/inheritance.swift
index cb0a0e1b7a355..d0e51df7381c6 100644
--- a/test/Interop/Cxx/foreign-reference/inheritance.swift
+++ b/test/Interop/Cxx/foreign-reference/inheritance.swift
@@ -1,9 +1,6 @@
 // REQUIRES: executable_test
 // RUN: %target-run-simple-swift(-cxx-interoperability-mode=default -Xfrontend -disable-availability-checking -I %S/Inputs)
 
-// TODO: Fix this lit test failure on windows rdar://145218056
-// XFAIL: OS=windows-msvc
-
 import Inheritance
 import StdlibUnittest
 
@@ -23,7 +20,9 @@ InheritanceTestSuite.test("Templated cast to base") {
   let sc: BaseT = cast(s)
   expectFalse(sc.isBase)
   let sx: BaseT = cxxCast(s)  // should instantiate I to SubT and O to BaseT
-  expectFalse(sc.isBase)
+  expectFalse(sx.isBase)
+  let sy: BaseT = Foo.cxxCast(s)  // should instantiate I to SubT and O to BaseT
+  expectFalse(sy.isBase)
 }
 
 InheritanceTestSuite.test("Templated cast to itself") {
diff --git a/test/Interop/Cxx/foreign-reference/invalid-retain-operation-errors.swift b/test/Interop/Cxx/foreign-reference/invalid-retain-operation-errors.swift
index a44068fc5a38a..03b6b4f4a1cfd 100644
--- a/test/Interop/Cxx/foreign-reference/invalid-retain-operation-errors.swift
+++ b/test/Interop/Cxx/foreign-reference/invalid-retain-operation-errors.swift
@@ -25,7 +25,7 @@ struct
     __attribute__((swift_attr("release:badRelease")))
 BadRetainRelease {};
 
-int badRetain(BadRetainRelease *v);
+float badRetain(BadRetainRelease *v);
 void badRelease(BadRetainRelease *v, int i);
 
 struct
@@ -235,7 +235,7 @@ public func test(x: NonExistent) { }
 @available(macOS 13.3, *)
 public func test(x: NoRetainRelease) { }
 
-// CHECK: error: specified retain function 'badRetain' is invalid; retain function must have 'void' or parameter return type
+// CHECK: error: specified retain function 'badRetain' is invalid; retain function must either return have 'void', the reference count as an integer, or the parameter type
 // CHECK: error: specified release function 'badRelease' is invalid; release function must have exactly one argument of type 'BadRetainRelease'
 @available(macOS 13.3, *)
 public func test(x: BadRetainRelease) { }
diff --git a/test/Interop/Cxx/foreign-reference/lifetime-operation-methods-module-interface.swift b/test/Interop/Cxx/foreign-reference/lifetime-operation-methods-module-interface.swift
new file mode 100644
index 0000000000000..73ad9a291ce11
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/lifetime-operation-methods-module-interface.swift
@@ -0,0 +1,49 @@
+// RUN: %target-swift-ide-test -print-module -cxx-interoperability-mode=upcoming-swift -I %swift_src_root/lib/ClangImporter/SwiftBridging -module-to-print=LifetimeOperationMethods -I %S/Inputs -source-filename=x | %FileCheck %s
+
+// CHECK: class RefCountedBox {
+// CHECK:   func doRetain() 
+// CHECK:   func doRelease()
+// CHECK: }
+// CHECK: class DerivedRefCountedBox {
+// CHECK:   func doRetain()
+// CHECK:   func doRelease()
+// CHECK: }
+
+// CHECK: class DerivedHasRelease {
+// CHECK:   func doRelease()
+// CHECK:   func doRetainInBase()
+// CHECK: }
+
+// CHECK: class TemplatedDerivedHasRelease<CFloat> {
+// CHECK:   var value: Float
+// CHECK:   func doReleaseTemplated()
+// CHECK:   func doRetainInBase()
+// CHECK: }
+// CHECK: class TemplatedDerivedHasRelease<CInt> {
+// CHECK:   var value: Int32
+// CHECK:   func doReleaseTemplated()
+// CHECK:   func doRetainInBase()
+// CHECK: }
+
+// CHECK: class CRTPDerived {
+// CHECK:   var value: Int32
+// CHECK: }
+
+// CHECK: class VirtualRetainRelease {
+// CHECK:   func doRetainVirtual()
+// CHECK:   func doReleaseVirtual()
+// CHECK: }
+// CHECK: class DerivedVirtualRetainRelease {
+// CHECK:   func doRetainVirtual()
+// CHECK:   func doReleaseVirtual()
+// CHECK: }
+
+// CHECK: class PureVirtualRetainRelease {
+// CHECK:   func doRetainPure()
+// CHECK:   func doReleasePure()
+// CHECK: }
+// CHECK: class DerivedPureVirtualRetainRelease {
+// CHECK:   func doRetainPure()
+// CHECK:   func doReleasePure()
+// CHECK:   var refCount: Int32
+// CHECK: }
diff --git a/test/Interop/Cxx/foreign-reference/lifetime-operation-methods-typechecker.swift b/test/Interop/Cxx/foreign-reference/lifetime-operation-methods-typechecker.swift
new file mode 100644
index 0000000000000..9241a939159da
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/lifetime-operation-methods-typechecker.swift
@@ -0,0 +1,6 @@
+// RUN: %target-typecheck-verify-swift -Xcc -DINCORRECT -I %S%{fs-sep}Inputs -I %swift_src_root/lib/ClangImporter/SwiftBridging -verify-additional-file %S%{fs-sep}Inputs%{fs-sep}lifetime-operation-methods.h -cxx-interoperability-mode=upcoming-swift -disable-availability-checking
+
+import LifetimeOperationMethods
+
+let _ = StaticRetainRelease(123)
+let _ = DerivedStaticRetainRelease(123, 456)
diff --git a/test/Interop/Cxx/foreign-reference/lifetime-operation-methods.swift b/test/Interop/Cxx/foreign-reference/lifetime-operation-methods.swift
new file mode 100644
index 0000000000000..f2e3532662cf9
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/lifetime-operation-methods.swift
@@ -0,0 +1,78 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=upcoming-swift -I %swift_src_root/lib/ClangImporter/SwiftBridging -Xfrontend -disable-availability-checking)
+
+// REQUIRES: executable_test
+
+// Temporarily disable when running with an older runtime (rdar://128681137)
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+import StdlibUnittest
+import LifetimeOperationMethods
+
+var LifetimeMethodsTestSuite = TestSuite("Lifetime operations that are instance methods")
+
+LifetimeMethodsTestSuite.test("retain/release methods") {
+  let a = RefCountedBox(123)
+  expectEqual(a.value, 123)
+  expectTrue(a.refCount > 0)
+  expectTrue(a.refCount < 10) // optimizations would affect the exact number
+}
+
+LifetimeMethodsTestSuite.test("retain/release methods from base type") {
+  let a = DerivedRefCountedBox(321, 456)
+  expectEqual(a.value, 321)
+  expectEqual(a.secondValue, 456)
+  expectTrue(a.refCount > 0)
+  expectTrue(a.refCount < 10) // optimizations would affect the exact number
+
+  a.secondValue = 789
+  expectEqual(a.secondValue, 789)
+}
+
+LifetimeMethodsTestSuite.test("retain in base type, release in derived type") {
+  let a = DerivedHasRelease(321)
+  expectEqual(a.value, 321)
+  expectTrue(a.refCount > 0)
+  expectTrue(a.refCount < 10) // optimizations would affect the exact number
+}
+
+LifetimeMethodsTestSuite.test("retain in base type, release in derived templated type") {
+  let a = TemplatedDerivedHasReleaseInt(456)
+  expectEqual(a.value, 456)
+  expectTrue(a.refCount > 0)
+  expectTrue(a.refCount < 10) // optimizations would affect the exact number
+
+  let b = TemplatedDerivedHasReleaseFloat(5.66)
+  expectEqual(b.value, 5.66)
+}
+
+LifetimeMethodsTestSuite.test("CRTP") {
+  let a = CRTPDerived(789)
+  expectEqual(a.value, 789)
+  expectTrue(a.refCount > 0)
+  expectTrue(a.refCount < 10) // optimizations would affect the exact number
+}
+
+LifetimeMethodsTestSuite.test("virtual retain/release") {
+  let a = VirtualRetainRelease(456)
+  expectEqual(a.value, 456)
+  expectTrue(a.refCount > 0)
+  expectTrue(a.refCount < 10) // optimizations would affect the exact number
+}
+
+LifetimeMethodsTestSuite.test("overridden virtual retain/release") {
+  let a = DerivedVirtualRetainRelease(456)
+  expectEqual(a.value, 456)
+  expectFalse(a.calledBase) // in optimized builds, we might not call retain/release at all
+  expectTrue(a.refCount > 0)
+  expectTrue(a.refCount < 10) // optimizations would affect the exact number
+}
+
+LifetimeMethodsTestSuite.test("overridden pure virtual retain/release") {
+  let a = DerivedPureVirtualRetainRelease(789)
+  expectEqual(a.value, 789)
+  expectTrue(a.refCount > 0)
+  expectTrue(a.refCount < 10) // optimizations would affect the exact number
+}
+
+runAllTests()
diff --git a/test/Interop/Cxx/foreign-reference/member-inheritance-module-interface.swift b/test/Interop/Cxx/foreign-reference/member-inheritance-module-interface.swift
new file mode 100644
index 0000000000000..5afa4554f8bce
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/member-inheritance-module-interface.swift
@@ -0,0 +1,160 @@
+// RUN: %target-swift-ide-test -print-module -cxx-interoperability-mode=swift-5.9 -print-implicit-attrs -module-to-print=MemberInheritance -I %S/Inputs -source-filename=x | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -cxx-interoperability-mode=swift-6 -print-implicit-attrs -module-to-print=MemberInheritance -I %S/Inputs -source-filename=x | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -cxx-interoperability-mode=upcoming-swift -print-implicit-attrs -module-to-print=MemberInheritance -I %S/Inputs -source-filename=x | %FileCheck %s
+
+// CHECK: class ImmortalBase {
+// CHECK:  func get42() -> Int32
+// CHECK:  func getOverridden42() -> Int32
+// CHECK: }
+// CHECK: class Immortal {
+// CHECK:  func getOverridden42() -> Int32
+// CHECK:  func get42() -> Int32
+// CHECK: }
+
+// CHECK: class Immortal2 {
+// CHECK-NEXT: final func virtualMethod(_: HasDestructor)
+// CHECK-NEXT: final func swiftVirtualRename()
+// CHECK: }
+
+// CHECK: class A1 {
+// CHECK:  final func virtualMethod() -> Int32
+// CHECK:  final func swiftFooRename() -> Int32
+// CHECK:  final func swiftBarRename() -> Int32
+// CHECK:  final func swiftParamsRename(a1 i: Int32) -> Int32
+// CHECK: }
+
+// CHECK: class B1 {
+// CHECK:  final func virtualMethod() -> Int32
+// CHECK:  final func swiftFooRename() -> Int32
+// CHECK:  final func swiftBarRename() -> Int32
+// CHECK:  final func swiftParamsRename(a1 i: Int32) -> Int32
+// CHECK: }
+
+// CHECK: class B2 {
+// CHECK:   final func virtualMethod() -> Int32
+// CHECK:   final func swiftFooRename() -> Int32
+// CHECK:   final func swiftBarRename() -> Int32
+// CHECK:   final func swiftParamsRename(a1 i: Int32) -> Int32
+// CHECK: }
+
+// CHECK: class C1 {
+// CHECK:  final func swiftFooRename() -> Int32
+// CHECK:  final func swiftBarRename() -> Int32
+// CHECK:  final func swiftParamsRename(a1 i: Int32) -> Int32
+// CHECK:  final func virtualMethod() -> Int32
+// CHECK: }
+
+// CHECK: class C2 {
+// CHECK:  final func virtualMethod() -> Int32
+// CHECK:  final func swiftFooRename() -> Int32
+// CHECK:  final func swiftBarRename() -> Int32
+// CHECK:  final func swiftParamsRename(a1 i: Int32) -> Int32
+// CHECK: }
+
+// CHECK: class A2 {
+// CHECK:  final func swiftVirtualMethod() -> Int32
+// CHECK:  final func swiftFooRename() -> Int32
+// CHECK:  final func A2BarRename() -> Int32
+// CHECK:  final func swiftParamsRename(a2 i: Int32) -> Int32
+// CHECK: }
+
+// CHECK: class D1 {
+// CHECK:  final func virtualMethod() -> Int32
+// CHECK:  final func swiftFooRename() -> Int32
+// CHECK:  final func swiftBarRename() -> Int32
+// CHECK:  final func swiftParamsRename(a1 i: Int32) -> Int32
+// CHECK:  final func swiftVirtualMethod() -> Int32
+// CHECK:  final func A2BarRename() -> Int32
+// CHECK:  final func swiftParamsRename(a2 i: Int32) -> Int32
+// CHECK: }
+
+// CHECK: class D2 {
+// CHECK:  final func swiftFooRename() -> Int32
+// CHECK:  @available(*, unavailable, message: "overrides{{.*}}")
+// CHECK:  final func virtualMethod() -> Int32
+// CHECK:  @available(*, unavailable, message: "overrides{{.*}}")
+// CHECK:  final func swiftBarRename() -> Int32
+// CHECK:  @available(*, unavailable, message: "overrides{{.*}}")
+// CHECK:  final func swiftParamsRename(a1 i: Int32) -> Int32
+// CHECK:  @available(*, unavailable, message: "overrides{{.*}}")
+// CHECK:  final func swiftVirtualMethod() -> Int32
+// CHECK:  @available(*, unavailable, message: "overrides{{.*}}")
+// CHECK:  final func A2BarRename() -> Int32
+// CHECK:  @available(*, unavailable, message: "overrides{{.*}}")
+// CHECK:  final func swiftParamsRename(a2 i: Int32) -> Int32
+// CHECK: }
+
+// CHECK: struct D3 {
+// CHECK:  final func virtualMethod() -> Int32
+// CHECK:  final func swiftFooRename() -> Int32
+// CHECK:  final func swiftBarRename() -> Int32
+// CHECK:  final func swiftParamsRename(a1 i: Int32) -> Int32
+// CHECK: }
+
+// CHECK: struct D4 {
+// CHECK:  final func swiftFooRename() -> Int32
+// CHECK:  final func swiftBarRename() -> Int32
+// CHECK:  final func swiftParamsRename(a1 i: Int32) -> Int32
+// CHECK:  final func virtualMethod() -> Int32
+// CHECK: }
+
+// CHECK: struct ValueType {
+// CHECK:   func virtualMethod() -> Int32
+// CHECK:   func swiftRenameMethodBase() -> Int32
+// CHECK:   func renameMethodDerived() -> Int32
+// CHECK:   @available(*, unavailable, message: "virtual function is not available in Swift because it is pure")
+// CHECK:   func pureVirtualMethod() -> Int32
+// CHECK:   @available(*, unavailable, message: "virtual function is not available in Swift because it is pure")
+// CHECK:   func swiftPureRenameBase() -> Int32
+// CHECK:   @available(*, unavailable, message: "virtual function is not available in Swift because it is pure")
+// CHECK:   func pureRenameDerived() -> Int32
+// CHECK: }
+
+// CHECK: class DerivedFRTValueType {
+// CHECK:   final func virtualMethod() -> Int32
+// CHECK:   final func swiftRenameMethodBase() -> Int32
+// CHECK:   final func renameMethodDerived() -> Int32
+// CHECK:   final func pureVirtualMethod() -> Int32
+// CHECK:   final func swiftPureRenameBase() -> Int32
+// CHECK:   final func pureRenameDerived() -> Int32
+// CHECK: }
+
+// CHECK: class EmptyDerivedFRTValueType {
+// CHECK:   func virtualMethod() -> Int32
+// CHECK:   func swiftRenameMethodBase() -> Int32
+// CHECK:   func renameMethodDerived() -> Int32
+// CHECK:   @available(*, unavailable, message: "virtual function is not available in Swift because it is pure")
+// CHECK:   func pureVirtualMethod() -> Int32
+// CHECK:   @available(*, unavailable, message: "virtual function is not available in Swift because it is pure")
+// CHECK:   func swiftPureRenameBase() -> Int32
+// CHECK:   @available(*, unavailable, message: "virtual function is not available in Swift because it is pure")
+// CHECK:   func pureRenameDerived() -> Int32
+// CHECK: }
+
+// CHECK: struct DerivedValueType {
+// CHECK:   func virtualMethod() -> Int32
+// CHECK:   func swiftRenameMethodBase() -> Int32
+// CHECK:   func renameMethodDerived() -> Int32
+// CHECK:   func pureVirtualMethod() -> Int32
+// CHECK:   func swiftPureRenameBase() -> Int32
+// CHECK:   func pureRenameDerived() -> Int32
+// CHECK: }
+
+// CHECK: class AbstractFRT {
+// CHECK:   final func pureVirtualMethod() -> Int32
+// CHECK:   final func swiftPureRenameBase() -> Int32
+// CHECK:   final func pureRenameDerived() -> Int32
+// CHECK: }
+
+// CHECK: class DerivedAbstractFRT {
+// CHECK:   init()
+// CHECK:   final func pureVirtualMethod() -> Int32
+// CHECK:   final func swiftPureRenameBase() -> Int32
+// CHECK:   final func pureRenameDerived() -> Int32
+// CHECK: }
+
+// CHECK: class EmptyDerivedAbstractFRT {
+// CHECK:   final func pureVirtualMethod() -> Int32
+// CHECK:   final func swiftPureRenameBase() -> Int32
+// CHECK:   final func pureRenameDerived() -> Int32
+// CHECK: }
diff --git a/test/Interop/Cxx/foreign-reference/member-inheritance-typechecker.swift b/test/Interop/Cxx/foreign-reference/member-inheritance-typechecker.swift
new file mode 100644
index 0000000000000..4556a2b8e5258
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/member-inheritance-typechecker.swift
@@ -0,0 +1,175 @@
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-5.9
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-6
+
+import MemberInheritance
+
+@available(SwiftStdlib 5.8, *)
+func takesImmortalBase(_ i: ImmortalBase) {
+  let _ = i.get42()
+  let _ = i.getOverridden42()
+  let _ = i.getIntValue()
+}
+
+@available(SwiftStdlib 5.8, *)
+func takesImmortal(_ i: Immortal) {
+  let _ = i.get42()
+  let _ = i.getOverridden42()
+  let _ = i.getIntValue()
+  i.setIntValue(1)
+}
+
+@available(SwiftStdlib 5.8, *)
+func takesDerivedFromImmortal(_ i: DerivedFromImmortal) {
+  let _ = i.get42()
+  let _ = i.getOverridden42()
+  let _ = i.getIntValue()
+  i.setIntValue(1)
+}
+
+@available(SwiftStdlib 5.8, *)
+func callsRenamedVirtualMethodsInFRT(_ i: Immortal2) {
+  i.virtualRename()  // expected-error {{value of type 'Immortal2' has no member 'virtualRename'}}
+  i.swiftVirtualRename()
+}
+
+@available(SwiftStdlib 5.8, *)
+func callsOverridesOfRenamedVirtualMethods(
+  _ a1: A1, _ a2: A2, _ b1: B1, _ b2: B2, _ c1: C1, _ c2: C2, _ d1: D1, _ d2: D2, _ d3: D3, _ d4: D4
+) {
+  let _ = a1.virtualMethod()
+  let _ = a1.fooRename()  // expected-error {{value of type 'A1' has no member 'fooRename'}}
+  let _ = a1.swiftFooRename()
+  let _ = a1.swiftParamsRename(a1: 42)
+
+  let _ = b1.virtualMethod()
+  let _ = b1.swiftVirtualMethod()  // expected-error {{value of type 'B1' has no member 'swiftVirtualMethod'}}
+  let _ = b1.fooRename()  // expected-error {{value of type 'B1' has no member 'fooRename'}}
+  let _ = b1.swiftFooRename()
+  let _ = b1.barRename()  // expected-error {{value of type 'B1' has no member 'barRename'}}
+  let _ = b1.swiftBarRename()
+  let _ = b1.B1BarRename()  // expected-error {{value of type 'B1' has no member 'B1BarRename'; did you mean 'swiftBarRename'}}
+  let _ = b1.swiftParamsRename(a1: 42)
+  let _ = b1.swiftParamsRename(b1: 42)  // expected-error {{incorrect argument label in call (have 'b1:', expected 'a1:')}}
+
+  let _ = b2.virtualMethod()
+  let _ = b2.fooRename()  // expected-error {{value of type 'B2' has no member 'fooRename'; did you mean 'swiftFooRename'?}}
+  let _ = b2.swiftFooRename()
+  let _ = b2.B2BarRename()  // expected-error {{value of type 'B2' has no member 'B2BarRename'; did you mean 'swiftBarRename'}}
+  let _ = b2.swiftParamsRename(a1: 42)
+
+  let _ = c1.virtualMethod()
+  let _ = c1.swiftVirtualMethod()  // expected-error {{value of type 'C1' has no member 'swiftVirtualMethod'}}
+  let _ = c1.fooRename()  // expected-error {{value of type 'C1' has no member 'fooRename'}}
+  let _ = c1.swiftFooRename()
+  let _ = c1.barRename()  // expected-error {{value of type 'C1' has no member 'barRename'}}
+  let _ = c1.swiftBarRename()
+  let _ = c1.B1BarRename()  // expected-error {{value of type 'C1' has no member 'B1BarRename'}}
+  let _ = c1.paramsRename(42)  // expected-error {{value of type 'C1' has no member 'paramsRename'}}
+  let _ = c1.swiftParamsRename(42)  // expected-error {{missing argument label 'a1:' in call}}
+  let _ = c1.swiftParamsRename(a1: 42)
+
+  let _ = c2.virtualMethod()
+  let _ = c2.swiftVirtualMethod()  // expected-error {{value of type 'C2' has no member 'swiftVirtualMethod'}}
+  let _ = c2.fooRename()  // expected-error {{value of type 'C2' has no member 'fooRename'}}
+  let _ = c2.swiftFooRename()
+  let _ = c2.C2FooRename()  // expected-error {{value of type 'C2' has no member 'C2FooRename'}}
+  let _ = c2.barRename()  // expected-error {{value of type 'C2' has no member 'barRename'}}
+  let _ = c2.swiftBarRename()
+  let _ = c2.B1BarRename()  // expected-error {{value of type 'C2' has no member 'B1BarRename'}}
+  let _ = c2.paramsRename(42)  // expected-error {{value of type 'C2' has no member 'paramsRename'}}
+  let _ = c2.swiftParamsRename(a1: 42)
+  let _ = c2.swiftParamsRename(b1: 42)  // expected-error {{incorrect argument label in call (have 'b1:', expected 'a1:')}}
+
+  let _ = d1.virtualMethod()
+  let _ = d1.swiftVirtualMethod()
+  let _ = d1.fooRename()  // expected-error {{value of type 'D1' has no member 'fooRename'}}
+  let _ = d1.swiftFooRename()  // expected-error {{ambiguous use of 'swiftFooRename()'}}
+  let _ = d1.barRename()  // expected-error {{value of type 'D1' has no member 'barRename'}}
+  let _ = d1.swiftBarRename()
+  let _ = d1.A2BarRename()
+  let _ = d1.swiftParamsRename(a1: 42)
+  let _ = d1.swiftParamsRename(a2: 42)
+
+  let _ = d2.virtualMethod()  // expected-error {{'virtualMethod()' is unavailable: overrides multiple C++ methods with different Swift names}}
+  let _ = d2.swiftVirtualMethod()  // expected-error {{'swiftVirtualMethod()' is unavailable: overrides multiple C++ methods with different Swift names}}
+  let _ = d2.fooRename()  // expected-error {{value of type 'D2' has no member 'fooRename'}}
+  let _ = d2.swiftFooRename()
+  let _ = d2.barRename()  // expected-error {{value of type 'D2' has no member 'barRename'}}
+  let _ = d2.swiftBarRename()  // expected-error {{'swiftBarRename()' is unavailable: overrides multiple C++ methods with different Swift names}}
+  let _ = d2.A2BarRename()  // expected-error {{'A2BarRename()' is unavailable: overrides multiple C++ methods with different Swift names}}
+  let _ = d2.swiftParamsRename(a1: 42)  // expected-error {{'swiftParamsRename(a1:)' is unavailable: overrides multiple C++ methods with different Swift names}}
+  let _ = d2.swiftParamsRename(a2: 42)  // expected-error {{'swiftParamsRename(a2:)' is unavailable: overrides multiple C++ methods with different Swift names}}
+  let _ = d2.swiftParamsRename(b1: 42)  // expected-error {{no exact matches in call to instance method 'swiftParamsRename'}}
+
+  let _ = d3.virtualMethod() // expected-error {{ambiguous use of 'virtualMethod()'}}
+  let _ = d3.swiftVirtualMethod()  // expected-error {{value of type 'D3' has no member 'swiftVirtualMethod'}}
+  let _ = d3.fooRename()  // expected-error {{value of type 'D3' has no member 'fooRename'}}
+  let _ = d3.swiftFooRename() // expected-error {{ambiguous use of 'swiftFooRename()'}}
+  let _ = d3.barRename()  // expected-error {{value of type 'D3' has no member 'barRename'}}
+  let _ = d3.swiftBarRename() // expected-error {{ambiguous use of 'swiftBarRename()'}}
+  let _ = d3.B1BarRename()  // expected-error {{value of type 'D3' has no member 'B1BarRename'}}
+  let _ = d3.swiftParamsRename(a1: 42) // expected-error {{ambiguous use of 'swiftParamsRename(a1:)'}}
+  let _ = d3.swiftParamsRename(b1: 42)  // expected-error {{no exact matches in call to instance method 'swiftParamsRename'}}
+
+  let _ = d4.virtualMethod() // expected-error {{ambiguous use of 'virtualMethod()'}}
+  let _ = d4.swiftVirtualMethod()  // expected-error {{value of type 'D4' has no member 'swiftVirtualMethod'}}
+  let _ = d4.fooRename()  // expected-error {{value of type 'D4' has no member 'fooRename'}}
+  let _ = d4.swiftFooRename()  // expected-error {{ambiguous use of 'swiftFooRename()'}}
+  let _ = d4.barRename()  // expected-error {{value of type 'D4' has no member 'barRename'}}
+  let _ = d4.swiftBarRename()  // expected-error {{ambiguous use of 'swiftBarRename()'}}
+  let _ = d4.B1BarRename()  // expected-error {{value of type 'D4' has no member 'B1BarRename'}}
+  let _ = d4.paramsRename(42)  // expected-error {{value of type 'D4' has no member 'paramsRename'}}
+  let _ = d4.swiftParamsRename(42) // expected-error {{no exact matches in call to instance method 'swiftParamsRename'}}
+  let _ = d4.swiftParamsRename(a1: 42) // expected-error {{ambiguous use of 'swiftParamsRename(a1:)'}}
+}
+
+@available(SwiftStdlib 5.8, *)
+func callsOverridesOfValueTypeMethods (_ frt: DerivedFRTValueType, _ empty_frt: EmptyDerivedFRTValueType, _ vt: DerivedValueType) {
+  let _ = frt.virtualMethod()
+  let _ = frt.renameMethodBase() // expected-error {{value of type 'DerivedFRTValueType' has no member 'renameMethodBase'}}
+  let _ = frt.swiftRenameMethodBase()
+  let _ = frt.renameMethodDerived()
+  let _ = frt.swiftRenameMethodDerived() // expected-error {{value of type 'DerivedFRTValueType' has no member 'swiftRenameMethodDerived'}}
+
+  let _ = frt.pureVirtualMethod()
+  let _ = frt.pureRenameBase() // expected-error {{value of type 'DerivedFRTValueType' has no member 'pureRenameBase'}}
+  let _ = frt.swiftPureRenameBase()
+  let _ = frt.pureRenameDerived()
+  let _ = frt.swiftPureRenameDerived() // expected-error {{value of type 'DerivedFRTValueType' has no member 'swiftPureRenameDerived'}}
+
+  let _ = empty_frt.virtualMethod()
+  let _ = empty_frt.renameMethodBase() // expected-error {{value of type 'EmptyDerivedFRTValueType' has no member 'renameMethodBase'}}
+  let _ = empty_frt.swiftRenameMethodBase()
+  let _ = empty_frt.renameMethodDerived()
+
+  let _ = empty_frt.pureVirtualMethod() // expected-error {{'pureVirtualMethod()' is unavailable: virtual function is not available in Swift because it is pure}}
+
+  let _ = vt.virtualMethod()
+  let _ = vt.renameMethodBase() // expected-error {{value of type 'DerivedValueType' has no member 'renameMethodBase'}}
+  let _ = vt.swiftRenameMethodBase()
+  let _ = vt.renameMethodDerived()
+  let _ = vt.swiftRenameMethodDerived() // expected-error {{value of type 'DerivedValueType' has no member 'swiftRenameMethodDerived'}}
+
+  let _ = vt.pureVirtualMethod()
+  let _ = vt.pureRenameBase() // expected-error {{value of type 'DerivedValueType' has no member 'pureRenameBase'}}
+  let _ = vt.swiftPureRenameBase()
+  let _ = vt.pureRenameDerived()
+  let _ = vt.swiftPureRenameDerived() // expected-error {{value of type 'DerivedValueType' has no member 'swiftPureRenameDerived'}}
+}
+
+@available(SwiftStdlib 5.8, *)
+func callsOverridesOfAbstractFRTMethods (_ frt: DerivedAbstractFRT, _ empty_frt: EmptyDerivedAbstractFRT) {
+  let _ = frt.pureVirtualMethod()
+  let _ = frt.pureRenameBase() // expected-error {{value of type 'DerivedAbstractFRT' has no member 'pureRenameBase'}}
+  let _ = frt.swiftPureRenameBase()
+  let _ = frt.pureRenameDerived()
+  let _ = frt.swiftPureRenameDerived() // expected-error {{value of type 'DerivedAbstractFRT' has no member 'swiftPureRenameDerived'}}
+
+  let _ = empty_frt.pureVirtualMethod()
+  let _ = empty_frt.pureRenameBase() // expected-error {{value of type 'EmptyDerivedAbstractFRT' has no member 'pureRenameBase'}}
+  let _ = empty_frt.swiftPureRenameBase()
+  let _ = empty_frt.pureRenameDerived()
+  let _ = empty_frt.swiftPureRenameDerived() // expected-error {{value of type 'EmptyDerivedAbstractFRT' has no member 'swiftPureRenameDerived'}}
+}
+
diff --git a/test/Interop/Cxx/foreign-reference/member-inheritance.swift b/test/Interop/Cxx/foreign-reference/member-inheritance.swift
index 62ae5023ec677..2ea300b7c0445 100644
--- a/test/Interop/Cxx/foreign-reference/member-inheritance.swift
+++ b/test/Interop/Cxx/foreign-reference/member-inheritance.swift
@@ -1,11 +1,14 @@
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -enable-experimental-cxx-interop -Xcc -fignore-exceptions)
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=swift-5.9)
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=swift-6)
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=upcoming-swift)
+// RUN: %target-run-simple-swift(-g -I %S/Inputs -cxx-interoperability-mode=default)
 //
 // REQUIRES: executable_test
 
 import StdlibUnittest
 import MemberInheritance
 
-var FunctionsTestSuite = TestSuite("Calling functions in base foreign reference classes")
+var FunctionsTestSuite = TestSuite("Calling functions in foreign reference classes")
 
 FunctionsTestSuite.test("base member FRT calls do not require copying") {
   let derived = makeCopyTrackedDerivedClass(42)!
@@ -68,4 +71,112 @@ FunctionsTestSuite.test("base member FRT subscript accessing reference FRT throu
   expectEqual(frt.getX(), 0)
 }
 
+if #available(SwiftStdlib 5.8, *) {
+  FunctionsTestSuite.test("virtual members in FRT") {
+    let i = Immortal.create()
+    expectEqual(42, i.get42())
+    expectEqual(0, i.getIntValue())
+
+    let base = castToImmortalBase(i)
+    expectEqual(42, base.get42())
+    expectEqual(42, base.getOverridden42())
+    expectEqual(0, base.getIntValue())
+
+    i.setIntValue(566)
+    expectEqual(566, i.getIntValue())
+    expectEqual(566, base.getIntValue())
+
+    let d = DerivedFromImmortal.create()
+    expectEqual(42, d.get42())
+    expectEqual(42, d.getOverridden42())
+    d.setIntValue(321)
+    expectEqual(321, d.getIntValue())
+    let base2 = castToImmortalBase(castToImmortal(d))
+    expectEqual(321, base2.getIntValue())
+  }
+}
+
+#if !os(Windows) 
+// FIXME in Windows, non-trivial C++ class with trivial ABI is not yet available in Swift
+FunctionsTestSuite.test("C++ virtual method with complex parameter") {
+  @available(SwiftStdlib 5.8, *)
+  func f(simpleClass: HasDestructor, immortalClass: Immortal2) {
+    immortalClass.virtualMethod(simpleClass)
+  }
+}
+#endif
+
+if #available(SwiftStdlib 5.8, *) {
+  FunctionsTestSuite.test("renamed C++ virtual method") {
+    func f(immortalClass: Immortal2) {
+      immortalClass.swiftVirtualRename()
+    }
+
+    let a1 = A1.create()
+    expectEqual(a1.virtualMethod(), 111)
+    expectEqual(a1.swiftFooRename(), 112)
+    expectEqual(a1.swiftBarRename(), 113)
+    expectEqual(a1.swiftParamsRename(a1: 42), 42)
+
+    let b1 = B1.create()
+    expectEqual(b1.virtualMethod(), 211)
+    expectEqual(b1.swiftFooRename(), 212)
+    expectEqual(b1.swiftBarRename(), 213)
+    expectEqual(b1.swiftParamsRename(a1: 42), 42)
+
+    let b2 = B2.create()
+    expectEqual(b2.virtualMethod(), 221)
+    expectEqual(b2.swiftFooRename(), 222)
+    expectEqual(b2.swiftBarRename(), 223)
+
+    let c1 = C1.create()
+    expectEqual(c1.virtualMethod(), 211)
+    expectEqual(c1.swiftFooRename(), 312)
+    expectEqual(c1.swiftBarRename(), 313)
+    expectEqual(c1.swiftParamsRename(a1: 42), 42)
+
+    let c2 = C2.create()
+    expectEqual(c2.virtualMethod(), 321)
+    expectEqual(c2.swiftFooRename(), 322)
+    expectEqual(c2.swiftBarRename(), 323)
+    expectEqual(c2.swiftParamsRename(a1: 42), 42)
+
+    let a2 = A2.create()
+    expectEqual(a2.swiftVirtualMethod(), 121)
+    expectEqual(a2.swiftFooRename(), 122)
+    expectEqual(a2.A2BarRename(), 123)
+    expectEqual(a2.swiftParamsRename(a2: 42), 43)
+
+    let d1 = D1.create()
+    expectEqual(d1.virtualMethod(), 111)
+    expectEqual(d1.swiftBarRename(), 113)
+    expectEqual(d1.swiftParamsRename(a1: 42), 42)
+    // FIXME the method calls below return incorrect values
+    expectEqual(d1.swiftVirtualMethod(), 111)     // should be 121
+    expectEqual(d1.A2BarRename(), 113)            // should be 123
+    expectEqual(d1.swiftParamsRename(a2: 42), 42) // should be 43
+  } 
+}
+
+if #available(SwiftStdlib 5.8, *) {
+  FunctionsTestSuite.test("renamed C++ virtual methods in FRT, which derives from value type") {
+    let frt = DerivedFRTValueType.create()
+    expectEqual(frt.virtualMethod(), 211)
+    expectEqual(frt.swiftRenameMethodBase(), 212)
+    expectEqual(frt.renameMethodDerived(), 213)
+    expectEqual(frt.pureVirtualMethod(), 214)
+    expectEqual(frt.swiftPureRenameBase(), 215)
+    expectEqual(frt.pureRenameDerived(), 216)
+  }
+}
+
+if #available(SwiftStdlib 5.8, *) {
+  FunctionsTestSuite.test("renamed C++ pure virtual methods in FRT") {
+    let frt = DerivedAbstractFRT.create()      
+    expectEqual(frt.pureVirtualMethod(), 211)
+    expectEqual(frt.swiftPureRenameBase(), 212)
+    expectEqual(frt.pureRenameDerived(), 213)
+  }
+}
+
 runAllTests()
diff --git a/test/Interop/Cxx/foreign-reference/move-only-irgen.swift b/test/Interop/Cxx/foreign-reference/move-only-irgen.swift
index bb48b757c22a1..7eeb6e22e18e7 100644
--- a/test/Interop/Cxx/foreign-reference/move-only-irgen.swift
+++ b/test/Interop/Cxx/foreign-reference/move-only-irgen.swift
@@ -6,14 +6,11 @@ import MoveOnly
 // CHECK-LABEL: define {{.*}}swiftcc void @"$s4main4testyyF"
 
 // CHECK: [[X:%.*]] = alloca ptr
-// CHECK: [[TMP:%.*]] = alloca ptr
 
 // CHECK: [[CREATED:%.*]] = call ptr @{{_ZN8MoveOnly6createEv|"\?create\@MoveOnly\@\@SAPEAU1\@XZ"}}()
 // CHECK: store ptr [[CREATED]], ptr [[X]]
-// CHECK: store ptr [[CREATED]], ptr [[TMP]]
 
-// CHECK: [[TMP_LOAD:%.*]] = load ptr, ptr [[TMP]]
-// CHECK: call i32 @{{_ZNK8MoveOnly4testEv|"\?test\@MoveOnly\@\@QEBAHXZ"}}(ptr [[TMP_LOAD]])
+// CHECK: call i32 @{{_ZNK8MoveOnly4testEv|"\?test\@MoveOnly\@\@QEBAHXZ"}}(ptr [[CREATED]])
 
 // CHECK: ret void
 
diff --git a/test/Interop/Cxx/foreign-reference/move-only-module-interface.swift b/test/Interop/Cxx/foreign-reference/move-only-module-interface.swift
index 82389914336ba..f20f81ac32e84 100644
--- a/test/Interop/Cxx/foreign-reference/move-only-module-interface.swift
+++ b/test/Interop/Cxx/foreign-reference/move-only-module-interface.swift
@@ -1,7 +1,7 @@
 // RUN: %target-swift-ide-test -print-module -module-to-print=MoveOnly -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
 
 // CHECK: class MoveOnly {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> MoveOnly
@@ -9,14 +9,14 @@
 // CHECK-NOT: func moveIntoResult(_ x: MoveOnly) -> MoveOnly
 
 // CHECK: class HasMoveOnlyChild {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK-NOT: var child: MoveOnly
 // CHECK:   class func create() -> HasMoveOnlyChild
 // CHECK: }
 // CHECK-NOT: func moveIntoResult(_ x: HasMoveOnlyChild) -> HasMoveOnlyChild
 
 // CHECK: class PrivateCopyCtor {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> PrivateCopyCtor
@@ -24,7 +24,7 @@
 // CHECK-NOT: func moveIntoResult(_ x: PrivateCopyCtor) -> PrivateCopyCtor
 
 // CHECK: class BadCopyCtor {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> BadCopyCtor
diff --git a/test/Interop/Cxx/foreign-reference/move-only-silgen.swift b/test/Interop/Cxx/foreign-reference/move-only-silgen.swift
index 821113afcaedb..e4ecd2948b906 100644
--- a/test/Interop/Cxx/foreign-reference/move-only-silgen.swift
+++ b/test/Interop/Cxx/foreign-reference/move-only-silgen.swift
@@ -15,11 +15,8 @@ import MoveOnly
 // CHECK: [[ACCESS_1:%.*]] = begin_access [read] [unknown] [[BOX]] : $*MoveOnly
 // CHECK: [[X_1:%.*]] = load [trivial] [[ACCESS_1]] : $*MoveOnly
 
-// CHECK: [[TMP:%.*]] = alloc_stack $MoveOnly
-// CHECK: store [[X_1]] to [trivial] [[TMP]]
-
-// CHECK: [[TEST_FN:%.*]] = function_ref @{{_ZNK8MoveOnly4testEv|\?test\@MoveOnly\@\@QEBAHXZ}} : $@convention(cxx_method) (@in_guaranteed MoveOnly) -> Int32
-// CHECK: apply [[TEST_FN]]([[TMP]]) : $@convention(cxx_method) (@in_guaranteed MoveOnly) -> Int32
+// CHECK: [[TEST_FN:%.*]] = function_ref @{{_ZNK8MoveOnly4testEv|\?test\@MoveOnly\@\@QEBAHXZ}} : $@convention(cxx_method) (MoveOnly) -> Int32
+// CHECK: apply [[TEST_FN]]([[X_1]]) : $@convention(cxx_method) (MoveOnly) -> Int32
 
 // CHECK: return
 // CHECK-LABEL: end sil function '$s4main4testyyF'
@@ -30,4 +27,4 @@ public func test() {
 
 // CHECK-LABEL: sil{{ \[available .*\] | }}[clang MoveOnly.create] @{{_ZN8MoveOnly6createEv|\?create\@MoveOnly\@\@SAPEAU1\@XZ}} : $@convention(c) () -> MoveOnly
 
-// CHECK-LABEL: sil{{ \[available .*\] | }}[clang MoveOnly.test] @{{_ZNK8MoveOnly4testEv|\?test\@MoveOnly\@\@QEBAHXZ}} : $@convention(cxx_method) (@in_guaranteed MoveOnly) -> Int32
+// CHECK-LABEL: sil{{ \[available .*\] | }}[clang MoveOnly.test] @{{_ZNK8MoveOnly4testEv|\?test\@MoveOnly\@\@QEBAHXZ}} : $@convention(cxx_method) (MoveOnly) -> Int32
diff --git a/test/Interop/Cxx/foreign-reference/multiple-protocol-conformances.swift b/test/Interop/Cxx/foreign-reference/multiple-protocol-conformances.swift
index 4364e8857ed7b..9d0ede722a952 100644
--- a/test/Interop/Cxx/foreign-reference/multiple-protocol-conformances.swift
+++ b/test/Interop/Cxx/foreign-reference/multiple-protocol-conformances.swift
@@ -2,8 +2,6 @@
 // RUN: split-file %s %t
 // RUN: %target-build-swift -I %S/Inputs %t/main.swift %t/second.swift -cxx-interoperability-mode=default -Xfrontend -disable-availability-checking
 
-// XFAIL: OS=windows-msvc
-
 //--- main.swift
 import ReferenceCounted
 
diff --git a/test/Interop/Cxx/foreign-reference/no-ctor-errors.swift b/test/Interop/Cxx/foreign-reference/no-ctor-errors.swift
deleted file mode 100644
index b8155509e8f9a..0000000000000
--- a/test/Interop/Cxx/foreign-reference/no-ctor-errors.swift
+++ /dev/null
@@ -1,25 +0,0 @@
-// RUN: rm -rf %t
-// RUN: split-file %s %t
-// RUN: not %target-swift-frontend -typecheck -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop 2>&1 | %FileCheck %s
-
-//--- Inputs/module.modulemap
-module Test {
-    header "test.h"
-    requires cplusplus
-}
-
-//--- Inputs/test.h
-struct
-    __attribute__((swift_attr("import_reference")))
-    __attribute__((swift_attr("retain:immortal")))
-    __attribute__((swift_attr("release:immortal")))
-HasCtor {
-  HasCtor(int a) {}
-};
-
-//--- test.swift
-
-import Test
-
-// CHECK: error: 'HasCtor' cannot be constructed because it has no accessible initializers
-let x = HasCtor(42)
\ No newline at end of file
diff --git a/test/Interop/Cxx/foreign-reference/not-any-object.swift b/test/Interop/Cxx/foreign-reference/not-any-object.swift
index af3899f99967a..e79810cdeb27d 100644
--- a/test/Interop/Cxx/foreign-reference/not-any-object.swift
+++ b/test/Interop/Cxx/foreign-reference/not-any-object.swift
@@ -22,5 +22,5 @@ import Test;
 public func test(_ _: AnyObject) {}
 
 // TODO: make this a better error.
-test(Empty.create()) // expected-error {{type of expression is ambiguous without a type annotation}}
+test(Empty.create()) // expected-error {{failed to produce diagnostic for expression}}
 test([Empty.create()][0]) // expected-error {{argument type 'Any' expected to be an instance of a class or class-constrained type}}
diff --git a/test/Interop/Cxx/foreign-reference/pass-as-parameter-irgen.swift b/test/Interop/Cxx/foreign-reference/pass-as-parameter-irgen.swift
new file mode 100644
index 0000000000000..17ef5dff24208
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/pass-as-parameter-irgen.swift
@@ -0,0 +1,39 @@
+// RUN: %target-swift-emit-irgen %s -I %S/Inputs -cxx-interoperability-mode=upcoming-swift -Xcc -fignore-exceptions -disable-availability-checking | %FileCheck %s
+
+import PassAsParameter
+
+public func refToPtr() {
+  var a = IntBox.create(123)
+  let aValue = extractValueFromRefToPtr(&a)
+  print(aValue)
+}
+// CHECK: define{{.*}} void {{.*}}refToPtr{{.*}}()
+// CHECK:   [[PTR_TO_PTR_TO_INT_BOX:%.*]] = alloca %TSo6IntBoxVSg
+// CHECK:   {{.*}} = call {{.*}} @{{.*}}extractValueFromRefToPtr{{.*}}(ptr [[PTR_TO_PTR_TO_INT_BOX]])
+
+public func constRefToPtr() {
+  let a = IntBox.create(456)
+  let aValue = extractValueFromConstRefToPtr(a)
+  print(aValue)
+}
+// CHECK: define{{.*}} void {{.*}}constRefToPtr{{.*}}()
+// CHECK:   [[PTR_TO_PTR_TO_INT_BOX2:%.*]] = alloca %TSo6IntBoxVSg
+// CHECK:   {{.*}} = call {{.*}} @{{.*}}extractValueFromConstRefToPtr{{.*}}(ptr [[PTR_TO_PTR_TO_INT_BOX2]])
+
+public func refToConstPtr() {
+  var a = IntBox.create(321)
+  let aValue = extractValueFromRefToConstPtr(&a)
+  print(aValue)
+}
+// CHECK: define{{.*}} void {{.*}}refToConstPtr{{.*}}()
+// CHECK:   [[PTR_TO_PTR_TO_INT_BOX3:%.*]] = alloca %TSo6IntBoxVSg
+// CHECK:   {{.*}} = call {{.*}} @{{.*}}extractValueFromRefToConstPtr{{.*}}(ptr [[PTR_TO_PTR_TO_INT_BOX3]])
+
+public func constRefToConstPtr() {
+  let a = IntBox.create(789)
+  let aValue = extractValueFromConstRefToConstPtr(a)
+  print(aValue)
+}
+// CHECK: define{{.*}} void {{.*}}constRefToConstPtr{{.*}}()
+// CHECK:   [[PTR_TO_PTR_TO_INT_BOX4:%.*]] = alloca %TSo6IntBoxVSg
+// CHECK:   {{.*}} = call {{.*}} @{{.*}}extractValueFromConstRefToConstPtr{{.*}}(ptr [[PTR_TO_PTR_TO_INT_BOX4]])
diff --git a/test/Interop/Cxx/foreign-reference/pass-as-parameter-module-interface.swift b/test/Interop/Cxx/foreign-reference/pass-as-parameter-module-interface.swift
new file mode 100644
index 0000000000000..b202258289692
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/pass-as-parameter-module-interface.swift
@@ -0,0 +1,11 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=PassAsParameter -I %S/Inputs -source-filename=x -cxx-interoperability-mode=upcoming-swift | %FileCheck %s
+
+// CHECK: func extractValueFromPtr(_ b: IntBox!) -> Int32
+// CHECK: func extractValueFromRef(_ b: IntBox) -> Int32
+// CHECK: func extractValueFromConstRef(_ b: IntBox) -> Int32
+// CHECK: func extractValueFromRefToPtr(_ b: inout IntBox!) -> Int32
+// CHECK: func extractValueFromRefToConstPtr(_ b: inout IntBox!) -> Int32
+// CHECK: func extractValueFromConstRefToPtr(_ b: IntBox!) -> Int32
+// CHECK: func extractValueFromConstRefToConstPtr(_ b: IntBox!) -> Int32
+
+// CHECK: func initializeByPtr(_ value: Int32, _ b: UnsafeMutablePointer<IntBox?>!)
diff --git a/test/Interop/Cxx/foreign-reference/pass-as-parameter.swift b/test/Interop/Cxx/foreign-reference/pass-as-parameter.swift
new file mode 100644
index 0000000000000..09f7c934121df
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/pass-as-parameter.swift
@@ -0,0 +1,62 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=upcoming-swift -Xfrontend -disable-availability-checking)
+
+// REQUIRES: executable_test
+
+// Temporarily disable when running with an older runtime (rdar://128681137)
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+import StdlibUnittest
+import PassAsParameter
+
+var PassAsParameterTestSuite = TestSuite("Passing foreign reference type as parameter")
+
+PassAsParameterTestSuite.test("pass as pointer") {
+  let a = IntBox.create(123)
+  let aValue = extractValueFromPtr(a)
+  expectEqual(aValue, 123)
+}
+
+PassAsParameterTestSuite.test("pass as reference") {
+  let a = IntBox.create(321)!
+  let aValue = extractValueFromRef(a)
+  expectEqual(aValue, 321)
+}
+
+PassAsParameterTestSuite.test("pass as const reference") {
+  let a = IntBox.create(321)!
+  let aValue = extractValueFromConstRef(a)
+  expectEqual(aValue, 321)
+}
+
+PassAsParameterTestSuite.test("pass as reference to pointer") {
+  var a = IntBox.create(123)
+  let aValue = extractValueFromRefToPtr(&a)
+  expectEqual(aValue, 123)
+}
+
+PassAsParameterTestSuite.test("pass as const reference to pointer") {
+  let a = IntBox.create(456)
+  let aValue = extractValueFromConstRefToPtr(a)
+  expectEqual(aValue, 456)
+}
+
+PassAsParameterTestSuite.test("pass as const reference to pointer") {
+  var a = IntBox.create(654)
+  let aValue = extractValueFromConstRefToPtr(a)
+  expectEqual(aValue, 654)
+}
+
+PassAsParameterTestSuite.test("pass as const reference to const pointer") {
+  var a = IntBox.create(789)
+  let aValue = extractValueFromConstRefToConstPtr(a)
+  expectEqual(aValue, 789)
+}
+
+PassAsParameterTestSuite.test("initialize by pointer") {
+  var a: IntBox!
+  initializeByPtr(987, &a)
+  expectEqual(a.value, 987)
+}
+
+runAllTests()
diff --git a/test/Interop/Cxx/foreign-reference/pod-irgen.swift b/test/Interop/Cxx/foreign-reference/pod-irgen.swift
index eb66d1fa3d0f4..d1d17254381aa 100644
--- a/test/Interop/Cxx/foreign-reference/pod-irgen.swift
+++ b/test/Interop/Cxx/foreign-reference/pod-irgen.swift
@@ -9,18 +9,15 @@ import POD
 // CHECK-LABEL: define {{.*}}swiftcc void @"$s4main4testyyF"
 
 // CHECK: [[X:%.*]] = alloca ptr
-// CHECK: [[TMP:%.*]] = alloca ptr
 
 // CHECK: [[CREATED:%.*]] = call ptr @{{_ZN7IntPair6createEv|"\?create\@IntPair\@\@SAPEAU1\@XZ"}}()
 // CHECK: store ptr [[CREATED]], ptr [[X]]
 
-// CHECK: [[B_FIELD:%.*]] = getelementptr inbounds %TSo7IntPairV, ptr [[CREATED]], i32 0, i32 1
-// CHECK: [[INT_VALUE:%.*]] = getelementptr inbounds %Ts5Int32V, ptr [[B_FIELD]], i32 0, i32 0
+// CHECK: [[B_FIELD:%.*]] = getelementptr inbounds{{.*}} %TSo7IntPairV, ptr [[CREATED]], i32 0, i32 1
+// CHECK: [[INT_VALUE:%.*]] = getelementptr inbounds{{.*}} %Ts5Int32V, ptr [[B_FIELD]], i32 0, i32 0
 // CHECK: store i32 42, ptr [[INT_VALUE]], align 4
 
-// CHECK: store ptr [[CREATED]], ptr [[TMP]]
-// CHECK: [[TMP_LOAD:%.*]] = load ptr, ptr [[TMP]]
-// CHECK: call i32 @{{_ZNK7IntPair4testEv|"\?test\@IntPair\@\@QEBAHXZ"}}(ptr [[TMP_LOAD]])
+// CHECK: call i32 @{{_ZNK7IntPair4testEv|"\?test\@IntPair\@\@QEBAHXZ"}}(ptr [[CREATED]])
 
 // CHECK: ret void
 
diff --git a/test/Interop/Cxx/foreign-reference/pod-module-interface.swift b/test/Interop/Cxx/foreign-reference/pod-module-interface.swift
index 5e3f950aaff43..984ac99257cf6 100644
--- a/test/Interop/Cxx/foreign-reference/pod-module-interface.swift
+++ b/test/Interop/Cxx/foreign-reference/pod-module-interface.swift
@@ -1,7 +1,7 @@
 // RUN: %target-swift-ide-test -print-module -module-to-print=POD -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
 
 // CHECK: class Empty {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> Empty
@@ -12,14 +12,14 @@
 // CHECK-NOT: func passThroughByValue(_ x: Empty) -> Empty
 
 // CHECK: class MultipleAttrs {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> MultipleAttrs
 // CHECK: }
 
 // CHECK: class IntPair {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   func instancePassThroughByRef(_ ref: IntPair) -> IntPair
@@ -33,7 +33,7 @@
 // CHECK: func passThroughByRef(_ x: IntPair) -> IntPair
 
 // CHECK: class RefHoldingPair {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK-NOT: pair
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
@@ -42,7 +42,7 @@
 // CHECK: }
 
 // CHECK: class RefHoldingPairRef {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> RefHoldingPairRef
@@ -51,7 +51,7 @@
 // CHECK: }
 
 // CHECK: class RefHoldingPairPtr {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> RefHoldingPairPtr
@@ -60,7 +60,6 @@
 // CHECK: }
 
 // CHECK: struct ValueHoldingPair {
-// CHECK-NOT: init
 // CHECK-NOT: pair
 // CHECK:   init()
 // CHECK:   func test() -> Int32
@@ -77,7 +76,7 @@
 // CHECK: }
 
 // CHECK: class BigType {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> BigType
diff --git a/test/Interop/Cxx/foreign-reference/pod-silgen.swift b/test/Interop/Cxx/foreign-reference/pod-silgen.swift
index 27d0b8083b986..c017d4b5dd590 100644
--- a/test/Interop/Cxx/foreign-reference/pod-silgen.swift
+++ b/test/Interop/Cxx/foreign-reference/pod-silgen.swift
@@ -21,10 +21,8 @@ import POD
 
 // CHECK: [[ACCESS_3:%.*]] = begin_access [read] [unknown] [[BOX]] : $*IntPair
 // CHECK: [[X_2:%.*]] = load [trivial] [[ACCESS_3]] : $*IntPair
-// CHECK: [[TMP:%.*]] = alloc_stack $IntPair
-// CHECK: store [[X_2]] to [trivial] [[TMP]]
-// CHECK: [[TEST_FN:%.*]] = function_ref @{{_ZNK7IntPair4testEv|\?test\@IntPair\@\@QEBAHXZ}} : $@convention(cxx_method) (@in_guaranteed IntPair) -> Int32
-// CHECK: apply [[TEST_FN]]([[TMP]]) : $@convention(cxx_method) (@in_guaranteed IntPair) -> Int32
+// CHECK: [[TEST_FN:%.*]] = function_ref @{{_ZNK7IntPair4testEv|\?test\@IntPair\@\@QEBAHXZ}} : $@convention(cxx_method) (IntPair) -> Int32
+// CHECK: apply [[TEST_FN]]([[X_2]]) : $@convention(cxx_method) (IntPair) -> Int32
 
 // CHECK: return
 // CHECK-LABEL: end sil function '$s4main4testyyF'
@@ -36,4 +34,4 @@ public func test() {
 
 // CHECK-LABEL: sil{{ \[available .*\] | }}[clang IntPair.create] @{{_ZN7IntPair6createEv|\?create\@IntPair\@\@SAPEAU1\@XZ}} : $@convention(c) () -> IntPair
 
-// CHECK-LABEL: sil{{ \[available .*\] | }}[clang IntPair.test] @{{_ZNK7IntPair4testEv|\?test\@IntPair\@\@QEBAHXZ}} : $@convention(cxx_method) (@in_guaranteed IntPair) -> Int32
+// CHECK-LABEL: sil{{ \[available .*\] | }}[clang IntPair.test] @{{_ZNK7IntPair4testEv|\?test\@IntPair\@\@QEBAHXZ}} : $@convention(cxx_method) (IntPair) -> Int32
diff --git a/test/Interop/Cxx/foreign-reference/print-reference.swift b/test/Interop/Cxx/foreign-reference/print-reference.swift
new file mode 100644
index 0000000000000..16d39df3bed95
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/print-reference.swift
@@ -0,0 +1,52 @@
+// RUN: %target-run-simple-swift(-cxx-interoperability-mode=default -I %S/Inputs) | %FileCheck %s
+
+// REQUIRES: executable_test
+
+// Temporarily disable when running with an older runtime (rdar://153205860)
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+import Printed
+
+func printCxxImmortalFRT() {
+    if #available(SwiftStdlib 6.2, *) {
+        let s = ImmortalFRT()
+        print(s)
+    } else {
+        print("runtime too old")
+    }
+}
+
+@available(SwiftStdlib 5.9, *)
+extension FRTCustomStringConvertible : CustomStringConvertible {
+    public var description: String {
+        return "FRTCustomStringConvertible(publ: \(publ))"
+    }
+}
+
+func printCxxFRTCustomStringConvertible() {
+    if #available(SwiftStdlib 5.9, *) {
+        let s = FRTCustomStringConvertible()
+        print(s)
+    } else {
+        print("runtime too old")
+    }
+}
+
+func printCxxFRType() {
+    if #available(SwiftStdlib 6.2, *) {
+        let s = FRType()
+        print(s)
+    } else {
+        print("runtime too old")
+    }
+}
+
+printCxxImmortalFRT()
+// CHECK: {{ImmortalFRT()|runtime too old}}
+
+printCxxFRTCustomStringConvertible()
+// CHECK: FRTCustomStringConvertible(publ: 2)
+
+printCxxFRType()
+// CHECK: {{FRType()|runtime too old}}
diff --git a/test/Interop/Cxx/foreign-reference/reference-counted-irgen.swift b/test/Interop/Cxx/foreign-reference/reference-counted-irgen.swift
index c5e723c6c86f6..5632431cefbfd 100644
--- a/test/Interop/Cxx/foreign-reference/reference-counted-irgen.swift
+++ b/test/Interop/Cxx/foreign-reference/reference-counted-irgen.swift
@@ -1,5 +1,4 @@
 // RUN: %target-swift-emit-irgen %s -I %S/Inputs -cxx-interoperability-mode=default -Xcc -fignore-exceptions -disable-availability-checking | %FileCheck %s
-// XFAIL: OS=windows-msvc
 
 import ReferenceCounted
 
@@ -17,6 +16,19 @@ public func getLocalCount() -> NS.LocalCount {
 // CHECK-NEXT: }
 
 
+public func useRetainReleaseOpsReturningRefCount() -> HasOpsReturningRefCount {
+    let result = HasOpsReturningRefCount.create()
+    return result
+}
+
+// CHECK:      define {{.*}}swiftcc ptr @"$s4main36useRetainReleaseOpsReturningRefCountSo03HasefgH0VyF"()
+// CHECK-NEXT: entry:
+// CHECK:        %0 = call ptr @{{_ZN23HasOpsReturningRefCount6createEv|"\?create\@HasOpsReturningRefCount\@\@SAPEAU1\@XZ"}}()
+// CHECK:        %1 = call i32 @{{_Z8RCRetainP23HasOpsReturningRefCount|"\?RCRetain\@\@YAIPEAUHasOpsReturningRefCount\@\@\@Z"}}(ptr %0)
+// CHECK:        ret ptr %0
+// CHECK-NEXT: }
+
+
 public func get42() -> Int32 {
     let result = NS.LocalCount.create()
     return result.returns42()
diff --git a/test/Interop/Cxx/foreign-reference/reference-counted.swift b/test/Interop/Cxx/foreign-reference/reference-counted.swift
index a9e63c07b5298..cc2df118235c9 100644
--- a/test/Interop/Cxx/foreign-reference/reference-counted.swift
+++ b/test/Interop/Cxx/foreign-reference/reference-counted.swift
@@ -2,7 +2,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -enable-experimental-cxx-interop -Xfrontend -validate-tbd-against-ir=none -Xfrontend -disable-llvm-verify -Xfrontend -disable-availability-checking -O)
 //
 // REQUIRES: executable_test
-// XFAIL: OS=windows-msvc
 
 // Temporarily disable when running with an older runtime (rdar://128681137)
 // UNSUPPORTED: use_os_stdlib
diff --git a/test/Interop/Cxx/foreign-reference/reference-in-virtual-methods.swift b/test/Interop/Cxx/foreign-reference/reference-in-virtual-methods.swift
new file mode 100644
index 0000000000000..18fcd3bc13d02
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/reference-in-virtual-methods.swift
@@ -0,0 +1,7 @@
+// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -I %swift_src_root/lib/ClangImporter/SwiftBridging %s -cxx-interoperability-mode=default -disable-availability-checking
+
+import VirtMethodWithRvalRef
+
+func f(_ x: CxxForeignRef, _ y: NonTrivial) {
+    x.takesRValRef(consuming: y)
+}
diff --git a/test/Interop/Cxx/foreign-reference/singleton-irgen.swift b/test/Interop/Cxx/foreign-reference/singleton-irgen.swift
index 9e2d0d115a8e4..8f7db9ca1be63 100644
--- a/test/Interop/Cxx/foreign-reference/singleton-irgen.swift
+++ b/test/Interop/Cxx/foreign-reference/singleton-irgen.swift
@@ -7,14 +7,11 @@ import Singleton
 // CHECK-LABEL: define {{.*}}swiftcc void @"$s4main4testyyF"
 
 // CHECK: [[X:%.*]] = alloca ptr
-// CHECK: [[TMP:%.*]] = alloca ptr
 
 // CHECK: [[CREATED:%.*]] = call ptr @{{_ZN21DeletedSpecialMembers6createEv|"\?create\@DeletedSpecialMembers\@\@SAPEAU1\@XZ"}}()
 // CHECK: store ptr [[CREATED]], ptr [[X]]
-// CHECK: store ptr [[CREATED]], ptr [[TMP]]
 
-// CHECK: [[TMP_LOAD:%.*]] = load ptr, ptr [[TMP]]
-// CHECK: call i32 @{{_ZNK21DeletedSpecialMembers4testEv|"\?test\@DeletedSpecialMembers\@\@QEBAHXZ"}}(ptr [[TMP_LOAD]])
+// CHECK: call i32 @{{_ZNK21DeletedSpecialMembers4testEv|"\?test\@DeletedSpecialMembers\@\@QEBAHXZ"}}(ptr [[CREATED]])
 
 // CHECK: call void @{{_Z8mutateItR21DeletedSpecialMembers|"\?mutateIt\@\@YAXAEAUDeletedSpecialMembers\@\@\@Z"}}(ptr [[CREATED]])
 
diff --git a/test/Interop/Cxx/foreign-reference/singleton-module-interface.swift b/test/Interop/Cxx/foreign-reference/singleton-module-interface.swift
index 83a1e95d763e7..bca9a093f2d06 100644
--- a/test/Interop/Cxx/foreign-reference/singleton-module-interface.swift
+++ b/test/Interop/Cxx/foreign-reference/singleton-module-interface.swift
@@ -1,7 +1,7 @@
 // RUN: %target-swift-ide-test -print-module -module-to-print=Singleton -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
 
 // CHECK: class DeletedDtor {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> DeletedDtor
@@ -10,7 +10,7 @@
 // CHECK: func mutateIt(_ x: DeletedDtor)
 
 // CHECK: class PrivateDtor {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> PrivateDtor
@@ -19,7 +19,7 @@
 // CHECK: func mutateIt(_ x: PrivateDtor)
 
 // CHECK: class DeletedSpecialMembers {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> DeletedSpecialMembers
@@ -28,7 +28,7 @@
 // CHECK: func mutateIt(_ x: DeletedSpecialMembers)
 
 // CHECK: class PrivateSpecialMembers {
-// CHECK-NOT: init
+// CHECK: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
 // CHECK:   class func create() -> PrivateSpecialMembers
diff --git a/test/Interop/Cxx/foreign-reference/singleton-silgen.swift b/test/Interop/Cxx/foreign-reference/singleton-silgen.swift
index 0db2d885838b3..85a224d38b898 100644
--- a/test/Interop/Cxx/foreign-reference/singleton-silgen.swift
+++ b/test/Interop/Cxx/foreign-reference/singleton-silgen.swift
@@ -15,11 +15,8 @@ import Singleton
 // CHECK: [[ACCESS_1:%.*]] = begin_access [read] [unknown] [[BOX]] : $*DeletedSpecialMembers
 // CHECK: [[X_1:%.*]] = load [trivial] [[ACCESS_1]] : $*DeletedSpecialMembers
 
-// CHECK: [[TMP:%.*]] = alloc_stack $DeletedSpecialMembers
-// CHECK: store [[X_1]] to [trivial] [[TMP]]
-
-// CHECK: [[TEST_FN:%.*]] = function_ref @{{_ZNK21DeletedSpecialMembers4testEv|\?test\@DeletedSpecialMembers\@\@QEBAHXZ}} : $@convention(cxx_method) (@in_guaranteed DeletedSpecialMembers) -> Int32
-// CHECK: apply [[TEST_FN]]([[TMP]]) : $@convention(cxx_method) (@in_guaranteed DeletedSpecialMembers) -> Int32
+// CHECK: [[TEST_FN:%.*]] = function_ref @{{_ZNK21DeletedSpecialMembers4testEv|\?test\@DeletedSpecialMembers\@\@QEBAHXZ}} : $@convention(cxx_method) (DeletedSpecialMembers) -> Int32
+// CHECK: apply [[TEST_FN]]([[X_1]]) : $@convention(cxx_method) (DeletedSpecialMembers) -> Int32
 // CHECK: [[ACCESS_2:%.*]] = begin_access [read] [unknown] [[BOX]] : $*DeletedSpecialMembers
 // CHECK: [[X_2:%.*]] = load [trivial] [[ACCESS_2]] : $*DeletedSpecialMembers
 
@@ -36,6 +33,6 @@ public func test() {
 
 // CHECK-LABEL: sil{{ \[available .*\] | }}[clang DeletedSpecialMembers.create] @{{_ZN21DeletedSpecialMembers6createEv|\?create\@DeletedSpecialMembers\@\@SAPEAU1\@XZ}} : $@convention(c) () -> DeletedSpecialMembers
 
-// CHECK-LABEL: sil{{ \[available .*\] | }}[clang DeletedSpecialMembers.test] @{{_ZNK21DeletedSpecialMembers4testEv|\?test\@DeletedSpecialMembers\@\@QEBAHXZ}} : $@convention(cxx_method) (@in_guaranteed DeletedSpecialMembers) -> Int32
+// CHECK-LABEL: sil{{ \[available .*\] | }}[clang DeletedSpecialMembers.test] @{{_ZNK21DeletedSpecialMembers4testEv|\?test\@DeletedSpecialMembers\@\@QEBAHXZ}} : $@convention(cxx_method) (DeletedSpecialMembers) -> Int32
 
 // CHECK-LABEL: sil{{ \[available .*\] | }}[serialized] [clang mutateIt] @{{_Z8mutateItR21DeletedSpecialMembers|\?mutateIt\@\@YAXAEAUDeletedSpecialMembers\@\@\@Z}} : $@convention(c) (DeletedSpecialMembers) -> ()
diff --git a/test/Interop/Cxx/foreign-reference/unimportable-member-layout-irgen.swift b/test/Interop/Cxx/foreign-reference/unimportable-member-layout-irgen.swift
index 37122a035e1b2..c6057f082dead 100644
--- a/test/Interop/Cxx/foreign-reference/unimportable-member-layout-irgen.swift
+++ b/test/Interop/Cxx/foreign-reference/unimportable-member-layout-irgen.swift
@@ -11,25 +11,25 @@ import MemberLayout
 // CHECK: %TSo23UnimportableMemberValueV = type <{ %Ts5Int32V, %Ts5Int32V, [8 x i8], %Ts5Int32V }>
 
 // CHECK-LABEL: define {{.*}}swiftcc i8 @"$s4testAA1ys4Int8VSo10IntCharRefV_tF"(ptr %0)
-// CHECK: getelementptr inbounds %TSo10IntCharRefV, ptr %0, i32 0, i32 1
+// CHECK: getelementptr inbounds{{.*}} %TSo10IntCharRefV, ptr %0, i32 0, i32 1
 public func test(y: IntCharRef) -> CChar {
   return y.b
 }
 
 // CHECK-LABEL: define {{.*}}swiftcc i8 @"$s4testAA1ys4Int8VSo12IntCharValueV_tF"(ptr %0)
-// CHECK: getelementptr inbounds %TSo12IntCharValueV, ptr %0, i32 0, i32 1
+// CHECK: getelementptr inbounds{{.*}} %TSo12IntCharValueV, ptr %0, i32 0, i32 1
 public func test(y: IntCharValue) -> CChar {
   return y.b
 }
 
 // CHECK-LABEL: define {{.*}}swiftcc i32 @"$s4testAA1ys5Int32VSo21UnimportableMemberRefV_tF"(ptr %0)
-// CHECK: getelementptr inbounds %TSo21UnimportableMemberRefV, ptr %0, i32 0, i32 3
+// CHECK: getelementptr inbounds{{.*}} %TSo21UnimportableMemberRefV, ptr %0, i32 0, i32 3
 public func test(y: UnimportableMemberRef) -> CInt {
   return y.y
 }
 
 // CHECK-LABEL: define {{.*}}swiftcc i32 @"$s4testAA1ys5Int32VSo23UnimportableMemberValueV_tF"(ptr %0)
-// CHECK: getelementptr inbounds %TSo23UnimportableMemberValueV, ptr %0, i32 0, i32 3
+// CHECK: getelementptr inbounds{{.*}} %TSo23UnimportableMemberValueV, ptr %0, i32 0, i32 3
 public func test(y: UnimportableMemberValue) -> CInt {
   return y.y
 }
diff --git a/test/Interop/Cxx/foreign-reference/unmanaged.swift b/test/Interop/Cxx/foreign-reference/unmanaged.swift
new file mode 100644
index 0000000000000..2a05b60773e30
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/unmanaged.swift
@@ -0,0 +1,20 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=default -Xfrontend -disable-availability-checking) | %FileCheck %s
+
+// REQUIRES: executable_test
+
+import POD
+
+extension Empty {
+   public static func == (lhs: Empty, rhs: Empty) -> Bool {
+        Unmanaged.passUnretained(lhs).toOpaque() == Unmanaged.passUnretained(rhs).toOpaque()
+   }
+}
+
+let x = Empty.create()
+let y = Empty.create()
+
+print(x == y)
+// CHECK: false
+
+print(x == x)
+// CHECK: true
diff --git a/test/Interop/Cxx/foreign-reference/weak-reference-typechecker.swift b/test/Interop/Cxx/foreign-reference/weak-reference-typechecker.swift
new file mode 100644
index 0000000000000..edc84b60c3a73
--- /dev/null
+++ b/test/Interop/Cxx/foreign-reference/weak-reference-typechecker.swift
@@ -0,0 +1,11 @@
+// RUN: %target-typecheck-verify-swift -cxx-interoperability-mode=default -I %S/Inputs -disable-availability-checking
+
+import POD
+
+struct HasWeakReference {
+  weak var x: Empty? // expected-error {{'Empty' is incompatible with 'weak' references, because it is a foreign reference type}}
+}
+
+struct HasUnownedReference {
+  unowned var x: Empty!
+}
diff --git a/test/Interop/Cxx/foreign-reference/witness-table-typechecker.swift b/test/Interop/Cxx/foreign-reference/witness-table-typechecker.swift
index 85a7130a00cc3..c65ece5f7ff2f 100644
--- a/test/Interop/Cxx/foreign-reference/witness-table-typechecker.swift
+++ b/test/Interop/Cxx/foreign-reference/witness-table-typechecker.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -cxx-interoperability-mode=default -disable-availability-checking -I %S/Inputs
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -cxx-interoperability-mode=default -disable-availability-checking -I %S/Inputs
 
 import WitnessTable
 
diff --git a/test/Interop/Cxx/foreign-reference/witness-table.swift b/test/Interop/Cxx/foreign-reference/witness-table.swift
index 4b88184cfaf53..e72e5c323828b 100644
--- a/test/Interop/Cxx/foreign-reference/witness-table.swift
+++ b/test/Interop/Cxx/foreign-reference/witness-table.swift
@@ -1,7 +1,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -enable-experimental-cxx-interop -Xfrontend -validate-tbd-against-ir=none -Xfrontend -disable-llvm-verify -g)
 //
 // REQUIRES: executable_test
-// XFAIL: OS=windows-msvc
 
 // Temporarily disable when running with an older runtime (rdar://128681577)
 // UNSUPPORTED: use_os_stdlib
diff --git a/test/Interop/Cxx/function/builtin-nullability-return-type-typechecker.swift b/test/Interop/Cxx/function/builtin-nullability-return-type-typechecker.swift
index 0d9df7b1ff481..7403490e3ef3f 100644
--- a/test/Interop/Cxx/function/builtin-nullability-return-type-typechecker.swift
+++ b/test/Interop/Cxx/function/builtin-nullability-return-type-typechecker.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -typecheck -verify -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=default -Xcc -D_CRT_SECURE_NO_WARNINGS %s
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -typecheck -verify -verify-ignore-unknown -I %S/Inputs -Xcc -D_CRT_SECURE_NO_WARNINGS %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -typecheck -verify -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=default -Xcc -D_CRT_SECURE_NO_WARNINGS %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -typecheck -verify -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -Xcc -D_CRT_SECURE_NO_WARNINGS %s
 
 import CustomStringBuiltins
 
diff --git a/test/Interop/Cxx/function/default-arguments-multifile.swift b/test/Interop/Cxx/function/default-arguments-multifile.swift
new file mode 100644
index 0000000000000..2dd3bc315d7b0
--- /dev/null
+++ b/test/Interop/Cxx/function/default-arguments-multifile.swift
@@ -0,0 +1,46 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: mkdir -p %t/artifacts
+
+// Multiple usages in the same module.
+// RUN: %target-build-swift %t/main.swift %t/b.swift %t/c.swift -cxx-interoperability-mode=upcoming-swift -I %S/Inputs -o %t/artifacts/out
+// RUN: %empty-directory(%t/artifacts)
+
+// Multiple usages across different modules.
+// RUN: %target-build-swift -emit-library -module-name BarLibrary -emit-module -emit-module-path %t/artifacts/BarLibrary.swiftmodule %t/b.swift %t/c.swift -cxx-interoperability-mode=upcoming-swift -I %S/Inputs -o %t/artifacts/%target-library-name(BarLibrary)
+// RUN: %target-build-swift %t/uses-library.swift -cxx-interoperability-mode=upcoming-swift -I %S/Inputs -I %t/artifacts -L %t/artifacts -lBarLibrary -o %t/artifacts/uses-library
+
+// FIXME: Windows test can be enabled once merge-modules step is removed from the old driver,
+// or the Windows CI starts to use the new driver to compile the compiler.
+// The windows toolchains still use the new driver so the CI failure worked
+// around here should not affect users on Windows.
+// UNSUPPORTED: OS=windows-msvc
+
+//--- main.swift
+import DefaultArguments
+public func foo() {
+  let _ = isZero()
+}
+foo()
+bar()
+baz()
+
+//--- b.swift
+import DefaultArguments
+public func bar() {
+  let _ = isZero()
+}
+
+//--- c.swift
+import DefaultArguments
+public func baz() {
+  let _ = isZero(123)
+}
+
+//--- uses-library.swift
+import DefaultArguments
+import BarLibrary
+
+let _ = isZero()
+bar()
+baz()
diff --git a/test/Interop/Cxx/function/default-arguments-typechecker.swift b/test/Interop/Cxx/function/default-arguments-typechecker.swift
index 2c4f802d21fa7..94b5caff1d8c9 100644
--- a/test/Interop/Cxx/function/default-arguments-typechecker.swift
+++ b/test/Interop/Cxx/function/default-arguments-typechecker.swift
@@ -1,6 +1,6 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-5.9
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-6
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-5.9
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=swift-6
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
 
 import DefaultArguments
 
diff --git a/test/Interop/Cxx/function/lit.local.cfg b/test/Interop/Cxx/function/lit.local.cfg
new file mode 100644
index 0000000000000..4e6b2cfd49774
--- /dev/null
+++ b/test/Interop/Cxx/function/lit.local.cfg
@@ -0,0 +1,6 @@
+# Make a local copy of the environment.
+config.environment = dict(config.environment)
+
+# FIXME: deserialization failure with the old driver in default-arguments-multifile.swift
+if 'SWIFT_USE_OLD_DRIVER' in config.environment: del config.environment['SWIFT_USE_OLD_DRIVER']
+if 'SWIFT_AVOID_WARNING_USING_OLD_DRIVER' in config.environment: del config.environment['SWIFT_AVOID_WARNING_USING_OLD_DRIVER']
diff --git a/test/Interop/Cxx/implementation-only-imports/check-constructor-visibility-inversed.swift b/test/Interop/Cxx/implementation-only-imports/check-constructor-visibility-inversed.swift
index 4fc5027b9fe5a..742d120486776 100644
--- a/test/Interop/Cxx/implementation-only-imports/check-constructor-visibility-inversed.swift
+++ b/test/Interop/Cxx/implementation-only-imports/check-constructor-visibility-inversed.swift
@@ -11,7 +11,7 @@
 @_implementationOnly import UserA
 import UserB
 
-@_inlineable
+@inlinable
 public func createAWrapper() {
   let _ = MagicWrapper()
 }
diff --git a/test/Interop/Cxx/implementation-only-imports/check-constructor-visibility.swift b/test/Interop/Cxx/implementation-only-imports/check-constructor-visibility.swift
index ebc5b492d3cbc..1fc60fe1c15b1 100644
--- a/test/Interop/Cxx/implementation-only-imports/check-constructor-visibility.swift
+++ b/test/Interop/Cxx/implementation-only-imports/check-constructor-visibility.swift
@@ -11,7 +11,7 @@
 import UserA
 @_implementationOnly import UserB
 
-@_inlineable
+@inlinable
 public func createAWrapper() {
   let _ = MagicWrapper()
 }
diff --git a/test/Interop/Cxx/implementation-only-imports/check-decls-are-identical.swift b/test/Interop/Cxx/implementation-only-imports/check-decls-are-identical.swift
index e33e7b5f4ceff..94ab5151380b6 100644
--- a/test/Interop/Cxx/implementation-only-imports/check-decls-are-identical.swift
+++ b/test/Interop/Cxx/implementation-only-imports/check-decls-are-identical.swift
@@ -7,7 +7,7 @@
 @_implementationOnly import DeclA
 import DeclB
 
-@_inlineable
+@inlinable
 public func callFortySomething() -> CInt {
   return getFortySomething()
 }
diff --git a/test/Interop/Cxx/implementation-only-imports/check-function-visibility-inversed.swift b/test/Interop/Cxx/implementation-only-imports/check-function-visibility-inversed.swift
index b8a1bbc989d4f..a975118b88e10 100644
--- a/test/Interop/Cxx/implementation-only-imports/check-function-visibility-inversed.swift
+++ b/test/Interop/Cxx/implementation-only-imports/check-function-visibility-inversed.swift
@@ -11,7 +11,7 @@
 import UserA
 @_implementationOnly import UserB
 
-@_inlineable
+@inlinable
 public func callFortyTwo() -> CInt {
   return getFortyTwo()
 }
diff --git a/test/Interop/Cxx/implementation-only-imports/check-function-visibility.swift b/test/Interop/Cxx/implementation-only-imports/check-function-visibility.swift
index 60e50a7076c6e..798ff663edd03 100644
--- a/test/Interop/Cxx/implementation-only-imports/check-function-visibility.swift
+++ b/test/Interop/Cxx/implementation-only-imports/check-function-visibility.swift
@@ -11,7 +11,7 @@
 @_implementationOnly import UserA
 import UserB
 
-@_inlineable
+@inlinable
 public func callFortyTwo() -> CInt {
   return getFortyTwo()
 }
diff --git a/test/Interop/Cxx/implementation-only-imports/check-operator-visibility-inversed.swift b/test/Interop/Cxx/implementation-only-imports/check-operator-visibility-inversed.swift
index 8299794340a07..5d53c8366a589 100644
--- a/test/Interop/Cxx/implementation-only-imports/check-operator-visibility-inversed.swift
+++ b/test/Interop/Cxx/implementation-only-imports/check-operator-visibility-inversed.swift
@@ -12,7 +12,7 @@ import UserA
 @_implementationOnly import UserB
 
 // Operator `+` is a non-member function.
-@_inlineable
+@inlinable
 public func addWrappers() {
   let wrapperA = MagicWrapper()
   let wrapperB = MagicWrapper()
@@ -20,7 +20,7 @@ public func addWrappers() {
 }
 
 // Operator `-` is a member function.
-@_inlineable
+@inlinable
 public func subtractWrappers() {
   var wrapperA = MagicWrapper()
   let wrapperB = MagicWrapper()
diff --git a/test/Interop/Cxx/implementation-only-imports/check-operator-visibility.swift b/test/Interop/Cxx/implementation-only-imports/check-operator-visibility.swift
index 1262796240575..992c4a789e4a1 100644
--- a/test/Interop/Cxx/implementation-only-imports/check-operator-visibility.swift
+++ b/test/Interop/Cxx/implementation-only-imports/check-operator-visibility.swift
@@ -12,7 +12,7 @@
 import UserB
 
 // Operator `+` is a non-member function.
-@_inlineable
+@inlinable
 public func addWrappers() {
   let wrapperA = MagicWrapper()
   let wrapperB = MagicWrapper()
@@ -20,7 +20,7 @@ public func addWrappers() {
 }
 
 // Operator `-` is a member function.
-@_inlineable
+@inlinable
 public func subtractWrappers() {
   var wrapperA = MagicWrapper()
   let wrapperB = MagicWrapper()
diff --git a/test/Interop/Cxx/implementation-only-imports/import-implementation-only-cxx-module-transitively.swift b/test/Interop/Cxx/implementation-only-imports/import-implementation-only-cxx-module-transitively.swift
new file mode 100644
index 0000000000000..2b216d5284a76
--- /dev/null
+++ b/test/Interop/Cxx/implementation-only-imports/import-implementation-only-cxx-module-transitively.swift
@@ -0,0 +1,60 @@
+// Crash reproducer from https://github.com/swiftlang/swift/issues/77047#issuecomment-2440103712
+// REQUIRES: OS=macosx
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: mkdir %t/artifacts
+
+// RUN: %target-swift-frontend -c %t/ChibiStdlib.swift -parse-stdlib -emit-module -emit-module-path %t/sdk/usr/lib/swift/Swift.swiftmodule/%module-target-triple.swiftmodule -module-name Swift -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -o %t/artifacts
+// RUN: %target-swift-frontend -c %t/XMLParser.swift -parse-as-library -emit-module -emit-module-path %t/sdk/usr/lib/swift/MyFoundationXML.swiftmodule/%module-target-triple.swiftmodule -module-name MyFoundationXML -module-link-name MyFoundationXML -resource-dir %t/sdk -O -I %t/include -o %t/artifacts  -sdk %t/sdk
+// RUN: %target-swift-frontend -c %t/Check.swift -o %t/artifacts -index-store-path %t/index-store -index-system-modules -resource-dir %t/sdk -parse-stdlib -sdk %t/sdk
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: mkdir %t/artifacts
+
+// RUN: %target-swift-frontend -c %t/ChibiStdlib.swift -parse-stdlib -emit-module -emit-module-path %t/sdk/usr/lib/swift/Swift.swiftmodule/%module-target-triple.swiftmodule -module-name Swift -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -o %t/artifacts
+// RUN: %target-swift-frontend -c %t/XMLParser.swift -enable-library-evolution -parse-as-library -emit-module -emit-module-path %t/sdk/usr/lib/swift/MyFoundationXML.swiftmodule/%module-target-triple.swiftmodule -module-name MyFoundationXML -module-link-name MyFoundationXML -resource-dir %t/sdk -O -I %t/include -o %t/artifacts  -sdk %t/sdk
+// RUN: %target-swift-frontend -c %t/Check.swift -o %t/artifacts -index-store-path %t/index-store -index-system-modules -resource-dir %t/sdk -parse-stdlib -sdk %t/sdk
+
+
+//--- Check.swift
+import MyFoundationXML
+
+//--- XMLParser.swift
+@_implementationOnly import _MyCFXMLInterface
+
+func _NSXMLParserExternalEntityWithURL(originalLoaderFunction: _CFXMLInterfaceExternalEntityLoader) {}
+
+//--- include/module.modulemap
+module _MyCFXMLInterface {
+  header "MyCFXMLInterface.h"
+}
+
+//--- include/MyCFXMLInterface.h
+#if !defined(__COREFOUNDATION_CFXMLINTERFACE__)
+#define __COREFOUNDATION_CFXMLINTERFACE__ 1
+
+typedef struct _xmlParserCtxt *_CFXMLInterfaceParserContext;
+typedef void (*_CFXMLInterfaceExternalEntityLoader)(_CFXMLInterfaceParserContext);
+
+#endif
+
+//--- ChibiStdlib.swift
+precedencegroup AssignmentPrecedence {
+  assignment: true
+  associativity: right
+}
+
+public typealias Void = ()
+
+@frozen
+public struct OpaquePointer {
+  @usableFromInline
+  internal var _rawValue: Builtin.RawPointer
+
+  @usableFromInline @_transparent
+  internal init(_ v: Builtin.RawPointer) {
+    self._rawValue = v
+  }
+}
diff --git a/test/Interop/Cxx/implementation-only-imports/skip-forward-declarations.swift b/test/Interop/Cxx/implementation-only-imports/skip-forward-declarations.swift
index 0ecf1e1a7e695..c407fb7a9e51e 100644
--- a/test/Interop/Cxx/implementation-only-imports/skip-forward-declarations.swift
+++ b/test/Interop/Cxx/implementation-only-imports/skip-forward-declarations.swift
@@ -7,7 +7,7 @@
 @_implementationOnly import UserA
 import UserC
 
-@_inlineable
+@inlinable
 public func createAWrapper() {
   let _ = MagicWrapper()
 }
diff --git a/test/Interop/Cxx/library-evolution/allow-c-in-cxx-mode-in-evolving-libraries.swift b/test/Interop/Cxx/library-evolution/allow-c-in-cxx-mode-in-evolving-libraries.swift
index 963998d3f6b9b..db4ca84e4ca8e 100644
--- a/test/Interop/Cxx/library-evolution/allow-c-in-cxx-mode-in-evolving-libraries.swift
+++ b/test/Interop/Cxx/library-evolution/allow-c-in-cxx-mode-in-evolving-libraries.swift
@@ -39,6 +39,9 @@ struct CStruct {
 }
 #endif
 
+typedef void (*my_sighandler_t)(int);
+typedef void (*my_other_cb)(CxxStruct);
+
 //--- test.swift
 
 import CxxModule
@@ -55,3 +58,9 @@ public func useCxxEnum(_ x: CxxEnum) { // expected-error {{cannot use enum 'CxxE
 // expected-error@+1 {{cannot use struct 'CxxStruct' here; C++ types from imported module 'CxxModule' do not support library evolution}}
 public func usesCxxStruct(_ x: CxxStruct) {
 }
+
+public func usesTypeAliasToFuncPtr(_ x: my_sighandler_t) {
+}
+
+public func usesTypeAliasToFuncPtr2(_ x: my_other_cb) { // expected-error {{cannot use type alias 'my_other_cb' here; C++ types from imported module 'CxxModule' do not support library evolution}}
+}
diff --git a/test/Interop/Cxx/library-evolution/allow-objc-in-cxx-mode-in-evolving-libraries.swift b/test/Interop/Cxx/library-evolution/allow-objc-in-cxx-mode-in-evolving-libraries.swift
index f52956b1704fe..3d621e37a3753 100644
--- a/test/Interop/Cxx/library-evolution/allow-objc-in-cxx-mode-in-evolving-libraries.swift
+++ b/test/Interop/Cxx/library-evolution/allow-objc-in-cxx-mode-in-evolving-libraries.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -typecheck -enable-library-evolution -enable-experimental-cxx-interop -verify
+// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -typecheck -enable-library-evolution -enable-experimental-cxx-interop -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 // REQUIRES: OS=macosx
diff --git a/test/Interop/Cxx/library-evolution/prohibit-cxx-api-in-evolving-libraries.swift b/test/Interop/Cxx/library-evolution/prohibit-cxx-api-in-evolving-libraries.swift
index 7ade6ba0c5b75..4feb377016558 100644
--- a/test/Interop/Cxx/library-evolution/prohibit-cxx-api-in-evolving-libraries.swift
+++ b/test/Interop/Cxx/library-evolution/prohibit-cxx-api-in-evolving-libraries.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -typecheck -enable-library-evolution -enable-experimental-cxx-interop -disable-availability-checking -disable-implicit-cxx-module-import -verify
+// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -typecheck -enable-library-evolution -enable-experimental-cxx-interop -disable-availability-checking -disable-implicit-cxx-module-import -verify -verify-ignore-unrelated
 
 // REQUIRES: OS=macosx
 
diff --git a/test/Interop/Cxx/library-evolution/prohibit-cxx-calls-in-evolving-inlinable-bodies.swift b/test/Interop/Cxx/library-evolution/prohibit-cxx-calls-in-evolving-inlinable-bodies.swift
index a5d9e6b3d280d..c4b4a5270bc87 100644
--- a/test/Interop/Cxx/library-evolution/prohibit-cxx-calls-in-evolving-inlinable-bodies.swift
+++ b/test/Interop/Cxx/library-evolution/prohibit-cxx-calls-in-evolving-inlinable-bodies.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -typecheck -enable-library-evolution -enable-experimental-cxx-interop -disable-implicit-cxx-module-import -verify
+// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -typecheck -enable-library-evolution -enable-experimental-cxx-interop -disable-implicit-cxx-module-import -verify -verify-ignore-unrelated
  
 // REQUIRES: OS=macosx
 
diff --git a/test/Interop/Cxx/modules/Inputs/ambiguous_a.h b/test/Interop/Cxx/modules/Inputs/ambiguous_a.h
new file mode 100644
index 0000000000000..623fe07e1f579
--- /dev/null
+++ b/test/Interop/Cxx/modules/Inputs/ambiguous_a.h
@@ -0,0 +1,3 @@
+#pragma once
+
+void f(int a);
diff --git a/test/Interop/Cxx/modules/Inputs/ambiguous_b.h b/test/Interop/Cxx/modules/Inputs/ambiguous_b.h
new file mode 100644
index 0000000000000..c93b9861d8d3a
--- /dev/null
+++ b/test/Interop/Cxx/modules/Inputs/ambiguous_b.h
@@ -0,0 +1,3 @@
+#pragma once
+
+void f(int a) __attribute__((enable_if(a > 0, ""))) __attribute__((enable_if(true, "")));
diff --git a/test/Interop/Cxx/modules/Inputs/module.modulemap b/test/Interop/Cxx/modules/Inputs/module.modulemap
index 02f06f1f8f09f..1c760fd08e66b 100644
--- a/test/Interop/Cxx/modules/Inputs/module.modulemap
+++ b/test/Interop/Cxx/modules/Inputs/module.modulemap
@@ -17,3 +17,13 @@ module TopLevelModule {
   }
   export *
 }
+
+module AmbiguousA {
+  header "ambiguous_a.h"
+  requires cplusplus
+}
+
+module AmbiguousB {
+  header "ambiguous_a.h"
+  requires cplusplus
+}
diff --git a/test/Interop/Cxx/modules/no-cxx-overlay-for-non-interop-interface.swift b/test/Interop/Cxx/modules/no-cxx-overlay-for-non-interop-interface.swift
new file mode 100644
index 0000000000000..2becf9e0c686d
--- /dev/null
+++ b/test/Interop/Cxx/modules/no-cxx-overlay-for-non-interop-interface.swift
@@ -0,0 +1,64 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/deps)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -typecheck %t/clientWithInteropDep.swift -I %t/deps -cxx-interoperability-mode=default -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -module-cache-path %t/module-cache &> %t/interop_dep.txt
+// RUN: cat %t/interop_dep.txt | %FileCheck %s -check-prefix=ENABLE-CHECK
+
+// RUN: %target-swift-frontend -typecheck %t/clientNoInteropDep.swift -I %t/deps -cxx-interoperability-mode=default -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -module-cache-path %t/module-cache &> %t/no_interop_dep.txt
+// RUN: cat %t/no_interop_dep.txt | %FileCheck %s -check-prefix=DISABLE-CHECK
+
+// RUN: %target-swift-frontend -typecheck %t/clientDarwin.swift -I %t/deps -cxx-interoperability-mode=default -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -module-cache-path %t/module-cache &> %t/darwin_dep.txt
+// RUN: cat %t/darwin_dep.txt | %FileCheck %s -check-prefix=DISABLE-CHECK
+
+// ENABLE-CHECK: remark: loaded module 'CxxStdlib' (overlay for a clang dependency)
+// DISABLE-CHECK-NOT: remark: loaded module 'CxxStdlib' (overlay for a clang dependency)
+
+//--- deps/bar.h
+#include "std_bar.h"
+void bar(void);
+
+//--- deps/std_bar.h
+void std_bar(void);
+
+//--- deps/module.modulemap
+module std_Bar [system] {
+  header "std_bar.h"
+  export *
+}
+
+module Bar [system] {
+  header "bar.h"
+  export *    
+}
+
+//--- deps/Foo.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name Foo -enable-library-evolution -Rmodule-loading
+import Bar
+public struct Foo1 {}
+
+//--- deps/FooNoInterop.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name FooNoInterop -enable-library-evolution
+// swift-module-flags-ignorable: -formal-cxx-interoperability-mode=off -Rmodule-loading
+import Bar
+public struct Foo2 {}
+
+//--- deps/Darwin.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name Darwin -enable-library-evolution
+// swift-module-flags-ignorable: -Rmodule-loading
+import Bar
+public struct Foo2 {}
+
+//--- clientWithInteropDep.swift
+import Foo
+
+//--- clientNoInteropDep.swift
+import FooNoInterop
+
+//--- clientDarwin.swift
+import Darwin
+
diff --git a/test/Interop/Cxx/modules/preferred-overload.swift b/test/Interop/Cxx/modules/preferred-overload.swift
new file mode 100644
index 0000000000000..f594191325433
--- /dev/null
+++ b/test/Interop/Cxx/modules/preferred-overload.swift
@@ -0,0 +1,8 @@
+// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=default
+
+import AmbiguousA
+import AmbiguousB
+
+func g(_ x: CInt) {
+    f(x)
+}
diff --git a/test/Interop/Cxx/namespace/Inputs/bridging-header.h b/test/Interop/Cxx/namespace/Inputs/bridging-header.h
new file mode 100644
index 0000000000000..1cc267d42c360
--- /dev/null
+++ b/test/Interop/Cxx/namespace/Inputs/bridging-header.h
@@ -0,0 +1,15 @@
+namespace NS1 {
+namespace NS2 {
+
+struct InBridgingHeader1 {};
+
+} // namespace NS2
+} // namespace NS1
+
+namespace NS1 {
+namespace NS2 {
+
+struct InBridgingHeader2 {};
+
+} // namespace NS2
+} // namespace NS1
diff --git a/test/Interop/Cxx/namespace/Inputs/constexpr-in-namespace.h b/test/Interop/Cxx/namespace/Inputs/constexpr-in-namespace.h
new file mode 100644
index 0000000000000..10db506b09de5
--- /dev/null
+++ b/test/Interop/Cxx/namespace/Inputs/constexpr-in-namespace.h
@@ -0,0 +1,4 @@
+namespace NS1 {
+constexpr int myConstexprInt = 123;
+static constexpr int myStaticConstexprInt = 456;
+} // namespace NS1
diff --git a/test/Interop/Cxx/namespace/Inputs/import-as-member.h b/test/Interop/Cxx/namespace/Inputs/import-as-member.h
new file mode 100644
index 0000000000000..750c26f135ce7
--- /dev/null
+++ b/test/Interop/Cxx/namespace/Inputs/import-as-member.h
@@ -0,0 +1,32 @@
+#define SWIFT_NAME(name) __attribute__((swift_name(name)))
+
+namespace MyNS {
+struct NestedStruct {
+  int value = 123;
+};
+}
+
+int nestedStruct_method(MyNS::NestedStruct p) SWIFT_NAME("MyNS.NestedStruct.method(self:)") { return p.value; }
+int nestedStruct_methodConstRef(const MyNS::NestedStruct &p) SWIFT_NAME("MyNS.NestedStruct.methodConstRef(self:)") { return p.value + 1; }
+inline int nestedStruct_methodInline(MyNS::NestedStruct p) SWIFT_NAME("MyNS.NestedStruct.methodInline(self:)") { return p.value + 2; }
+
+namespace MyNS {
+namespace MyDeepNS {
+struct DeepNestedStruct {
+  int value = 456;
+};
+}
+}
+
+int deepNestedStruct_method(MyNS::MyDeepNS::DeepNestedStruct p) SWIFT_NAME("MyNS.MyDeepNS.DeepNestedStruct.method(self:)") { return p.value; }
+int deepNestedStruct_methodConstRef(const MyNS::MyDeepNS::DeepNestedStruct &p) SWIFT_NAME("MyNS.MyDeepNS.DeepNestedStruct.methodConstRef(self:)") { return p.value + 2; }
+
+typedef MyNS::MyDeepNS::DeepNestedStruct DeepNestedStructTypedef;
+
+int deepNestedStructTypedef_method(DeepNestedStructTypedef p) SWIFT_NAME("DeepNestedStructTypedef.methodTypedef(self:)") { return p.value + 3; }
+int deepNestedStructTypedef_methodQualName(MyNS::MyDeepNS::DeepNestedStruct p) SWIFT_NAME("DeepNestedStructTypedef.methodTypedefQualName(self:)") { return p.value + 4; }
+
+namespace MyNS {
+int nestedStruct_nestedMethod(MyNS::NestedStruct p) SWIFT_NAME("MyNS.NestedStruct.nestedMethod(self:)") { return p.value + 3; }
+inline int nestedStruct_nestedMethodInline(MyNS::NestedStruct p) SWIFT_NAME("MyNS.NestedStruct.nestedMethodInline(self:)") { return p.value + 4; }
+}
diff --git a/test/Interop/Cxx/namespace/Inputs/module.modulemap b/test/Interop/Cxx/namespace/Inputs/module.modulemap
index fdfa543567049..6bd4e55048fc5 100644
--- a/test/Interop/Cxx/namespace/Inputs/module.modulemap
+++ b/test/Interop/Cxx/namespace/Inputs/module.modulemap
@@ -12,6 +12,17 @@ module ClassesSecondHeader {
   requires cplusplus
 }
 
+module ConstexprInNamespace {
+  header "constexpr-in-namespace.h"
+  requires cplusplus
+}
+
+module ExternWithinNamespace {
+  header "extern-within-namespace.h"
+  export *
+  requires cplusplus
+}
+
 module FreeFunctions {
   header "free-functions.h"
   requires cplusplus
@@ -60,6 +71,12 @@ module Enums {
   requires cplusplus
 }
 
+module ImportAsMember {
+  header "import-as-member.h"
+  export *
+  requires cplusplus
+}
+
 module MembersDirect {
   header "members-direct.h"
   requires cplusplus
@@ -69,3 +86,8 @@ module MembersTransitive {
   header "members-transitive.h"
   requires cplusplus
 }
+
+module UsingFromNamespace {
+  header "using-from-namespace.h"
+  requires cplusplus
+}
diff --git a/test/Interop/Cxx/namespace/Inputs/using-from-namespace.h b/test/Interop/Cxx/namespace/Inputs/using-from-namespace.h
new file mode 100644
index 0000000000000..0ad79a2ad6053
--- /dev/null
+++ b/test/Interop/Cxx/namespace/Inputs/using-from-namespace.h
@@ -0,0 +1,13 @@
+#pragma once
+
+namespace Test {
+  class Foo {};
+  namespace Test2 {
+  class Bar {};
+  } // namespace Test2
+
+  using Test2::Bar;
+} // namespace Test
+
+using Test::Bar;
+using Test::Foo;
diff --git a/test/Interop/Cxx/namespace/bridging-header-module-interface.swift b/test/Interop/Cxx/namespace/bridging-header-module-interface.swift
new file mode 100644
index 0000000000000..f068c5da6e3f1
--- /dev/null
+++ b/test/Interop/Cxx/namespace/bridging-header-module-interface.swift
@@ -0,0 +1,4 @@
+// RUN: %target-swift-ide-test -print-header -header-to-print %S/Inputs/bridging-header.h -import-objc-header %S/Inputs/bridging-header.h -source-filename=%s -cxx-interoperability-mode=upcoming-swift | %FileCheck %s
+
+// CHECK: struct InBridgingHeader1
+// CHECK: struct InBridgingHeader2
diff --git a/test/Interop/Cxx/namespace/constexpr-in-namespace-module-interface.swift b/test/Interop/Cxx/namespace/constexpr-in-namespace-module-interface.swift
new file mode 100644
index 0000000000000..0f8a70dda8522
--- /dev/null
+++ b/test/Interop/Cxx/namespace/constexpr-in-namespace-module-interface.swift
@@ -0,0 +1,6 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=ConstexprInNamespace -I %S/Inputs -source-filename=x -cxx-interoperability-mode=upcoming-swift | %FileCheck %s
+
+// CHECK: enum NS1 {
+// CHECK:   static var myConstexprInt: Int32
+// CHECK:   static var myStaticConstexprInt: Int32
+// CHECK: }
diff --git a/test/Interop/Cxx/namespace/constexpr-in-namespace.swift b/test/Interop/Cxx/namespace/constexpr-in-namespace.swift
new file mode 100644
index 0000000000000..16f6a2c58a6f3
--- /dev/null
+++ b/test/Interop/Cxx/namespace/constexpr-in-namespace.swift
@@ -0,0 +1,17 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=upcoming-swift)
+// REQUIRES: executable_test
+
+import StdlibUnittest
+import ConstexprInNamespace
+
+var NamespacesTestSuite = TestSuite("Constexpr in namespace")
+
+NamespacesTestSuite.test("constexpr int") {
+  expectEqual(NS1.myConstexprInt, 123)
+}
+
+NamespacesTestSuite.test("static constexpr int") {
+  expectEqual(NS1.myStaticConstexprInt, 456)
+}
+
+runAllTests()
diff --git a/test/Interop/Cxx/namespace/import-as-member-module-interface.swift b/test/Interop/Cxx/namespace/import-as-member-module-interface.swift
new file mode 100644
index 0000000000000..cd6be06ac827d
--- /dev/null
+++ b/test/Interop/Cxx/namespace/import-as-member-module-interface.swift
@@ -0,0 +1,16 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=ImportAsMember -I %S/Inputs -source-filename=x -cxx-interoperability-mode=upcoming-swift | %FileCheck %s
+
+// CHECK:      extension MyNS.NestedStruct {
+// CHECK-NEXT:   func method() -> Int32
+// CHECK-NEXT:   func methodConstRef() -> Int32
+// CHECK-NEXT:   func methodInline() -> Int32
+// CHECK-NEXT:   func nestedMethod() -> Int32
+// CHECK-NEXT:   func nestedMethodInline() -> Int32
+// CHECK-NEXT: }
+
+// CHECK:      extension MyNS.MyDeepNS.DeepNestedStruct {
+// CHECK-NEXT:   func method() -> Int32
+// CHECK-NEXT:   func methodConstRef() -> Int32
+// CHECK-NEXT:   func methodTypedef() -> Int32
+// CHECK-NEXT:   func methodTypedefQualName() -> Int32
+// CHECK-NEXT: }
diff --git a/test/Interop/Cxx/namespace/import-as-member-typechecker.swift b/test/Interop/Cxx/namespace/import-as-member-typechecker.swift
new file mode 100644
index 0000000000000..d42d43bd72093
--- /dev/null
+++ b/test/Interop/Cxx/namespace/import-as-member-typechecker.swift
@@ -0,0 +1,24 @@
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
+
+import ImportAsMember
+
+func takesNestedStruct(_ s: MyNS.NestedStruct) {
+  _ = s.method()
+  _ = s.methodConstRef()
+  _ = s.nestedMethod()
+  _ = s.nestedMethodInline()
+
+  _ = nestedStruct_method(s) // expected-error {{'nestedStruct_method' has been replaced by instance method 'MyNS.NestedStruct.method()'}}
+}
+
+func takesDeepNestedStruct(_ s: MyNS.MyDeepNS.DeepNestedStruct) {
+  _ = s.method()
+  _ = s.methodConstRef()
+  _ = s.methodTypedef()
+  _ = s.methodTypedefQualName()
+
+  _ = deepNestedStruct_method(s) // expected-error {{'deepNestedStruct_method' has been replaced by instance method 'MyNS.MyDeepNS.DeepNestedStruct.method()'}}
+}
+
+MyNS.method() // expected-error {{type 'MyNS' has no member 'method'}}
+MyNS.nestedMethod() // expected-error {{failed to produce diagnostic for expression}}
diff --git a/test/Interop/Cxx/namespace/import-as-member.swift b/test/Interop/Cxx/namespace/import-as-member.swift
new file mode 100644
index 0000000000000..6275598d9048b
--- /dev/null
+++ b/test/Interop/Cxx/namespace/import-as-member.swift
@@ -0,0 +1,31 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=upcoming-swift)
+
+// REQUIRES: executable_test
+
+import StdlibUnittest
+import ImportAsMember
+
+var NamespacesTestSuite = TestSuite("Import as member of namespace")
+
+NamespacesTestSuite.test("Struct in a namespace") {
+  let s = MyNS.NestedStruct()
+  expectEqual(123, s.method())
+  expectEqual(124, s.methodConstRef())
+  expectEqual(125, s.methodInline())
+}
+
+NamespacesTestSuite.test("Struct in a deep namespace") {
+  let s = MyNS.MyDeepNS.DeepNestedStruct()
+  expectEqual(456, s.method())
+  expectEqual(458, s.methodConstRef())
+  expectEqual(459, s.methodTypedef())
+  expectEqual(460, s.methodTypedefQualName())
+}
+
+NamespacesTestSuite.test("Struct and function in a namespace") {
+  let s = MyNS.NestedStruct()
+  expectEqual(126, s.nestedMethod())
+  expectEqual(127, s.nestedMethodInline())
+}
+
+runAllTests()
diff --git a/test/Interop/Cxx/namespace/inline-namespace-ambiguity-error.swift b/test/Interop/Cxx/namespace/inline-namespace-ambiguity-error.swift
index 9ad64b1e93a82..d9a2d96975a7f 100644
--- a/test/Interop/Cxx/namespace/inline-namespace-ambiguity-error.swift
+++ b/test/Interop/Cxx/namespace/inline-namespace-ambiguity-error.swift
@@ -1,6 +1,6 @@
 // RUN: rm -rf %t
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unknown -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -verify-ignore-unknown -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop
 
 //--- Inputs/module.modulemap
 module namespaces {
diff --git a/test/Interop/Cxx/namespace/inline-namespace-function-call-broken.swift b/test/Interop/Cxx/namespace/inline-namespace-function-call-broken.swift
deleted file mode 100644
index 93606f6d589f0..0000000000000
--- a/test/Interop/Cxx/namespace/inline-namespace-function-call-broken.swift
+++ /dev/null
@@ -1,26 +0,0 @@
-// RUN: rm -rf %t
-// RUN: split-file %s %t
-// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unknown -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop
-
-//--- Inputs/module.modulemap
-module namespaces {
-  header "test.h"
-  requires cplusplus
-}
-//--- Inputs/test.h
-namespace Parent {
-inline namespace InlineChild {
-
-void functionInInlineChild();
-
-} // namespace InlineChild
-} // namespace Parent
-
-//--- test.swift
-
-import namespaces;
-
-// Swift's typechecker currently doesn't allow calling a function from inline namespace when it's referenced through the parent namespace.
-func test() {
-  Parent.functionInInlineChild() // expected-error {{type of expression is ambiguous without a type annotation}}
-}
diff --git a/test/Interop/Cxx/namespace/inline-namespace-function-call.swift b/test/Interop/Cxx/namespace/inline-namespace-function-call.swift
new file mode 100644
index 0000000000000..d338299479b17
--- /dev/null
+++ b/test/Interop/Cxx/namespace/inline-namespace-function-call.swift
@@ -0,0 +1,50 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -c -verify -verify-ignore-unknown -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop -verify
+
+//--- Inputs/module.modulemap
+module namespaces {
+  header "test.h"
+  requires cplusplus
+}
+//--- Inputs/test.h
+namespace Parent {
+inline namespace InlineChild {
+inline namespace InlineChild2 {
+void functionInInlineChild2();
+int GlobalVariableInInlineChild2;
+struct GlobalTypeInInlineChild2 {};
+} // namespace InlineChild2
+void functionInInlineChild();
+int GlobalVariableInInlineChild;
+struct GlobalTypeInInlineChild {};
+namespace Child {
+void functionInInlineChildsNonInlineNamespace();
+} // namespace Child
+} // namespace InlineChild
+} // namespace Parent
+
+//--- test.swift
+
+import namespaces;
+
+func test() {
+  Parent.functionInInlineChild()
+  Parent.GlobalVariableInInlineChild = 1
+  Parent.functionInInlineChild2()
+  Parent.GlobalVariableInInlineChild2 = 2
+  Parent.InlineChild.functionInInlineChild()
+  Parent.InlineChild.GlobalVariableInInlineChild = 3
+  Parent.InlineChild.functionInInlineChild2()
+  Parent.InlineChild.GlobalVariableInInlineChild2 = 4
+  Parent.InlineChild.InlineChild2.functionInInlineChild2()
+  Parent.InlineChild.InlineChild2.GlobalVariableInInlineChild2 = 5
+  // FIXME: fix the below case.
+  Parent.Child.functionInInlineChildsNonInlineNamespace() // expected-error {{failed to produce diagnostic for expression}}
+  Parent.InlineChild.Child.functionInInlineChildsNonInlineNamespace()
+}
+
+func testTypes(x: Parent.GlobalTypeInInlineChild, y: Parent.GlobalTypeInInlineChild2,
+               x2: Parent.InlineChild.GlobalTypeInInlineChild,
+               y2: Parent.InlineChild.GlobalTypeInInlineChild2,
+               y3: Parent.InlineChild.InlineChild2.GlobalTypeInInlineChild2) {}
diff --git a/test/Interop/Cxx/namespace/templates-with-forward-decl-module-interface.swift b/test/Interop/Cxx/namespace/templates-with-forward-decl-module-interface.swift
index 293420872145e..014f313206179 100644
--- a/test/Interop/Cxx/namespace/templates-with-forward-decl-module-interface.swift
+++ b/test/Interop/Cxx/namespace/templates-with-forward-decl-module-interface.swift
@@ -12,7 +12,7 @@
 // CHECK-NEXT:     init(fwd: NS1.ForwardDeclared<CInt>)
 // CHECK-NEXT:     typealias MyInt = Int32
 // CHECK-NEXT:     var fwd: NS1.ForwardDeclared<CInt>
-// CHECK-NEXT:     static let intValue: NS1.Decl<CInt>.MyInt
+// CHECK-NEXT:     static var intValue: NS1.Decl<CInt>.MyInt { get }
 // CHECK-NEXT:   }
 // CHECK-NEXT:   @available(*, unavailable, message: "Un-specialized class templates are not currently supported. Please use a specialization of this type.")
 // CHECK-NEXT:   struct Decl<T> {
diff --git a/test/Interop/Cxx/namespace/using-from-namespace.swift b/test/Interop/Cxx/namespace/using-from-namespace.swift
new file mode 100644
index 0000000000000..3dde4542fb263
--- /dev/null
+++ b/test/Interop/Cxx/namespace/using-from-namespace.swift
@@ -0,0 +1,6 @@
+// RUN: %target-swift-emit-irgen -I %S/Inputs/ -cxx-interoperability-mode=default -g %s
+
+import UsingFromNamespace
+
+func f(_ foo: Foo) {}
+func g(_ bar: Bar) {}
diff --git a/test/Interop/Cxx/objc-correctness/Inputs/cxx-frt.h b/test/Interop/Cxx/objc-correctness/Inputs/cxx-frt.h
index e4d03ada7ea47..c1c3906d776e7 100644
--- a/test/Interop/Cxx/objc-correctness/Inputs/cxx-frt.h
+++ b/test/Interop/Cxx/objc-correctness/Inputs/cxx-frt.h
@@ -16,7 +16,7 @@ void releaseCxxRefType(CxxRefType *_Nonnull b) {}
 
 @interface Bridge : NSObject
 
-+ (struct CxxRefType *)objCMethodReturningFRTUnannotated; // expected-warning {{'objCMethodReturningFRTUnannotated' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
++ (struct CxxRefType *)objCMethodReturningFRTUnannotated; // expected-note {{'objCMethodReturningFRTUnannotated()' is defined here}}
 + (struct CxxRefType *)objCMethodReturningFRTUnowned
     __attribute__((swift_attr("returns_unretained")));
 + (struct CxxRefType *)objCMethodReturningFRTOwned
@@ -24,7 +24,7 @@ void releaseCxxRefType(CxxRefType *_Nonnull b) {}
 + (struct CxxRefType *)objCMethodReturningFRTBothAnnotations // expected-error {{'objCMethodReturningFRTBothAnnotations' cannot be annotated with both SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED}}
     __attribute__((swift_attr("returns_unretained")))
     __attribute__((swift_attr("returns_retained")));
-+ (struct CxxValType *)objCMethodReturningNonCxxFrtAnannotated // expected-error {{'objCMethodReturningNonCxxFrtAnannotated' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
++ (struct CxxValType *)objCMethodReturningNonCxxFrtAnannotated // expected-warning {{'objCMethodReturningNonCxxFrtAnannotated' should not be annotated with SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
     __attribute__((swift_attr("returns_retained")));
 
 @end
diff --git a/test/Interop/Cxx/objc-correctness/appkit-uikit.swift b/test/Interop/Cxx/objc-correctness/appkit-uikit.swift
index 2569d66f97cb7..fc247f760e8ba 100644
--- a/test/Interop/Cxx/objc-correctness/appkit-uikit.swift
+++ b/test/Interop/Cxx/objc-correctness/appkit-uikit.swift
@@ -1,4 +1,5 @@
 // RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default %s
+// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default %s -swift-version 6
 
 // REQUIRES: objc_interop
 // REQUIRES: VENDOR=apple
@@ -9,6 +10,11 @@ import AppKit
 
 var _: AttributeScopes.AppKitAttributes.UnderlineStyleAttribute! = nil
 
+var _ = NSEvent.SpecialKey.upArrow.rawValue
+var _ = NSEvent.SpecialKey.enter.rawValue
+var _ = NSUpArrowFunctionKey
+var _ = NSEnterCharacter
+
 #elseif canImport(UIKit)
 import UIKit
 
diff --git a/test/Interop/Cxx/objc-correctness/at-objc-api-using-non-trivial-cxx.swift b/test/Interop/Cxx/objc-correctness/at-objc-api-using-non-trivial-cxx.swift
index 72c2c9a6e459c..920d54ea44761 100644
--- a/test/Interop/Cxx/objc-correctness/at-objc-api-using-non-trivial-cxx.swift
+++ b/test/Interop/Cxx/objc-correctness/at-objc-api-using-non-trivial-cxx.swift
@@ -42,14 +42,14 @@ import NonTrivial
 
 @objc
 class ObjCObject: NSObject {
-  @objc var prop: NonTrivial // expected-error {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  @objc var prop: NonTrivial // expected-error {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-1 {{non-trivial C++ classes cannot be represented in Objective-C}}
 
   @objc var trivProp: Trivial
 
   override init() { fatalError() }
 
-  @objc func getNonTrivial() -> NonTrivialDestrOnly { // expected-error {{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  @objc func getNonTrivial() -> NonTrivialDestrOnly { // expected-error {{method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
     // expected-note@-1 {{non-trivial C++ classes cannot be represented in Objective-C}}
     fatalError()
   }
diff --git a/test/Interop/Cxx/objc-correctness/call-to-generated-init-with-nsstring.swift b/test/Interop/Cxx/objc-correctness/call-to-generated-init-with-nsstring.swift
index 51de465f4bb7e..ad8ee601a2331 100644
--- a/test/Interop/Cxx/objc-correctness/call-to-generated-init-with-nsstring.swift
+++ b/test/Interop/Cxx/objc-correctness/call-to-generated-init-with-nsstring.swift
@@ -56,6 +56,6 @@ testSdump()
 // IR-TRIVIAL: }
 
 // IR-NONTRIVIAL-LABEL: define {{.*}} swiftcc void @"$s4main9testSdumpyyF"()
-// IR-NONTRIVIAL: call {{.*}} @_ZN1SC1ERKS_
 // IR-NONTRIVIAL: call {{.*}} @_ZNK1S4dumpEv
+// IR-NONTRIVIAL: call {{.*}} @_ZN1SC1ERKS_
 // IR-NONTRIVIAL: call {{.*}} @_ZN1SD1Ev
diff --git a/test/Interop/Cxx/objc-correctness/darwin-macros.swift b/test/Interop/Cxx/objc-correctness/darwin-macros.swift
new file mode 100644
index 0000000000000..77f52a632f32d
--- /dev/null
+++ b/test/Interop/Cxx/objc-correctness/darwin-macros.swift
@@ -0,0 +1,7 @@
+// RUN: %target-swift-frontend -cxx-interoperability-mode=default -typecheck -verify -I %S/Inputs %s
+
+// REQUIRES: OS=macosx
+
+import Darwin
+
+let _ = COPYFILE_ALL
diff --git a/test/Interop/Cxx/objc-correctness/memchr.swift b/test/Interop/Cxx/objc-correctness/memchr.swift
new file mode 100644
index 0000000000000..d0618aa574847
--- /dev/null
+++ b/test/Interop/Cxx/objc-correctness/memchr.swift
@@ -0,0 +1,13 @@
+// RUN: %target-swift-frontend -cxx-interoperability-mode=default -typecheck -verify -I %S/Inputs %s
+
+// REQUIRES: objc_interop
+// REQUIRES: VENDOR=apple
+
+import Darwin
+
+func test_memchr() {
+    var src = "hello"
+    var _ = src.withUTF8 { srcBuf in
+        Darwin.memchr(srcBuf.baseAddress!, 137, src.count)
+    }
+}
diff --git a/test/Interop/Cxx/objc-correctness/ns-enum-with-unavailable-typedef.swift b/test/Interop/Cxx/objc-correctness/ns-enum-with-unavailable-typedef.swift
new file mode 100644
index 0000000000000..77ae9f4f2b8d5
--- /dev/null
+++ b/test/Interop/Cxx/objc-correctness/ns-enum-with-unavailable-typedef.swift
@@ -0,0 +1,60 @@
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -typecheck -verify %t/main.swift -I %t/include -module-name main
+// RUN: %target-swift-frontend -typecheck -verify %t/main.swift -I %t/include -module-name main -cxx-interoperability-mode=default
+// REQUIRES: objc_interop
+
+//--- include/module.modulemap
+module ObjCModule {
+    header "header.h"
+}
+
+//--- include/header.h
+#include <Foundation/Foundation.h>
+
+#define UNAVAILABLE API_UNAVAILABLE(macos)
+
+UNAVAILABLE
+typedef NS_ENUM(NSUInteger, MyUnavailableEnum) {
+    MyUnavailableEnumCase1 = 0,
+    MyUnavailableEnumCase2,
+};
+
+UNAVAILABLE
+void unavailableParam(MyUnavailableEnum e);
+
+UNAVAILABLE
+MyUnavailableEnum unavailableReturn(void);
+
+struct UNAVAILABLE UnavailableStruct {
+  MyUnavailableEnum field;
+};
+
+UNAVAILABLE
+@interface UnavailableClass
+@property (nonatomic, readonly) MyUnavailableEnum prop;
+@end
+
+UNAVAILABLE
+__attribute__((swift_name("getter:UnavailableStruct.iProp(self:)")))
+inline MyUnavailableEnum getUnavailableInjProp(struct UnavailableStruct s) {
+  return MyUnavailableEnumCase1;
+}
+
+//--- main.swift
+import Foundation
+import ObjCModule
+
+@available(*, unavailable)
+func useParam(_ e: MyUnavailableEnum) { unavailableParam(e) }
+
+@available(*, unavailable)
+func useReturn() -> MyUnavailableEnum { return unavailableReturn() }
+
+@available(*, unavailable)
+func useField(_ o: UnavailableStruct) -> MyUnavailableEnum { return o.field }
+
+@available(*, unavailable)
+func useIProp(_ o: UnavailableStruct) -> MyUnavailableEnum { return o.iProp }
+
+@available(*, unavailable)
+func useProp(_ o: UnavailableClass) -> MyUnavailableEnum { return o.prop }
diff --git a/test/Interop/Cxx/objc-correctness/objc-returning-cxx-frt-diagnostics.swift b/test/Interop/Cxx/objc-correctness/objc-returning-cxx-frt-diagnostics.swift
index 72ed8c6797a8a..40adaff181db4 100644
--- a/test/Interop/Cxx/objc-correctness/objc-returning-cxx-frt-diagnostics.swift
+++ b/test/Interop/Cxx/objc-correctness/objc-returning-cxx-frt-diagnostics.swift
@@ -1,5 +1,7 @@
 // RUN: rm -rf %t
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs  %s -cxx-interoperability-mode=upcoming-swift -verify-additional-file %S/Inputs/cxx-frt.h -Xcc -Wno-return-type
+// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs  %s -cxx-interoperability-mode=upcoming-swift -enable-experimental-feature WarnUnannotatedReturnOfCxxFrt -verify-additional-file %S/Inputs/cxx-frt.h -Xcc -Wno-return-type
+
+// REQUIRES: swift_feature_WarnUnannotatedReturnOfCxxFrt
 
 import CxxForeignRef
 
@@ -7,5 +9,5 @@ import CxxForeignRef
 func testObjCMethods() {
     _ = Bridge.objCMethodReturningFRTBothAnnotations()
     _ = Bridge.objCMethodReturningNonCxxFrtAnannotated()
-    _ = Bridge.objCMethodReturningFRTUnannotated()
+    _ = Bridge.objCMethodReturningFRTUnannotated() // expected-warning {{cannot infer the ownership of the returned value, annotate 'objCMethodReturningFRTUnannotated()' with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED}}
 }
diff --git a/test/Interop/Cxx/operators/Inputs/member-inline.h b/test/Interop/Cxx/operators/Inputs/member-inline.h
index ff5a2a41f218d..2ec044e6c6a08 100644
--- a/test/Interop/Cxx/operators/Inputs/member-inline.h
+++ b/test/Interop/Cxx/operators/Inputs/member-inline.h
@@ -157,6 +157,20 @@ struct ReadWriteIntArray {
   };
 };
 
+#if __cplusplus >= 202302L
+struct NullarySubscript {
+  int operator[]() const { return 42; }
+  int &operator[]() { return field; }
+  int field;
+};
+
+struct BinarySubscript {
+  int operator[](int x, int y) const { return x + y; }
+  int &operator[](int, int) { return field; }
+  int field;
+};
+#endif
+
 struct __attribute__((swift_attr("import_owned"))) ReadOnlyIntArray {
 private:
   int values[5] = { 1, 2, 3, 4, 5 };
diff --git a/test/Interop/Cxx/operators/Inputs/non-member-inline.h b/test/Interop/Cxx/operators/Inputs/non-member-inline.h
index 96f087e879f87..3ccdc94c579bf 100644
--- a/test/Interop/Cxx/operators/Inputs/non-member-inline.h
+++ b/test/Interop/Cxx/operators/Inputs/non-member-inline.h
@@ -29,6 +29,10 @@ inline LoadableIntWrapper operator^(LoadableIntWrapper lhs, LoadableIntWrapper r
   return LoadableIntWrapper{.value = lhs.value ^ rhs.value};
 }
 
+inline LoadableIntWrapper operator~(LoadableIntWrapper lhs) {
+  return LoadableIntWrapper{.value = ~lhs.value};
+}
+
 inline LoadableIntWrapper operator&(LoadableIntWrapper lhs, LoadableIntWrapper rhs) {
   return LoadableIntWrapper{.value = lhs.value & rhs.value};
 }
@@ -94,6 +98,29 @@ inline bool operator==(const ClassWithOperatorEqualsParamUnnamed &,
   return false;
 }
 
+struct RValueArithmetic {
+  int value;
+};
+
+RValueArithmetic operator+(const RValueArithmetic &lhs,
+                           RValueArithmetic &&rhs) {
+  return {lhs.value + rhs.value};
+}
+
+struct LValueAndRValueArithmetic {
+  int value;
+};
+
+LValueAndRValueArithmetic operator+(const LValueAndRValueArithmetic &lhs,
+                                    const LValueAndRValueArithmetic &rhs) {
+  return {lhs.value + rhs.value};
+}
+
+LValueAndRValueArithmetic operator+(const LValueAndRValueArithmetic &lhs,
+                                    LValueAndRValueArithmetic &&rhs) {
+  return {lhs.value + rhs.value};
+}
+
 // Make sure that we don't crash on templated operators
 template<typename T> struct S {};
 template<typename T> S<T> operator+(S<T> lhs, S<T> rhs);
diff --git a/test/Interop/Cxx/operators/member-inline-irgen.swift b/test/Interop/Cxx/operators/member-inline-irgen.swift
index c3f5472ab4ba7..33b7e9d394e58 100644
--- a/test/Interop/Cxx/operators/member-inline-irgen.swift
+++ b/test/Interop/Cxx/operators/member-inline-irgen.swift
@@ -24,7 +24,7 @@ public func index(_ arr: inout ReadOnlyIntArray, _ arg: Int32) -> Int32 { arr[ar
 // CHECK: call ptr [[NAME:@(_ZNK16ReadOnlyIntArrayixEi|"\?\?AReadOnlyIntArray@@QEBAAEBHH@Z")]](ptr {{.*}}, {{i32|i64}}{{.*}})
 // CHECK: define {{.*}}ptr [[NAME]](ptr {{.*}}, {{i32|\[1 x i32\]|i64|%struct.ReadOnlyIntArray\* byval\(%struct.ReadOnlyIntArray\)}}{{.*}})
 // CHECK:   [[THIS:%.*]] = load ptr, ptr
-// CHECK:   [[VALUES:%.*]] = getelementptr inbounds %struct.ReadOnlyIntArray, ptr [[THIS]]
+// CHECK:   [[VALUES:%.*]] = getelementptr inbounds{{.*}} %struct.ReadOnlyIntArray, ptr [[THIS]]
 // CHECK:   [[VALUE:%.*]] = getelementptr inbounds [5 x {{i32|i64}}], ptr [[VALUES]]
 // CHECK:   ret ptr [[VALUE]]
 
@@ -33,7 +33,7 @@ public func index(_ arr: inout ReadWriteIntArray, _ arg: Int32, _ val: Int32) {
 // CHECK: call ptr [[NAME:@(_ZN17ReadWriteIntArrayixEi|"\?\?AReadWriteIntArray@@QEAAAEAHH@Z")]](ptr {{.*}}, {{i32|i64}}{{.*}})
 // CHECK: define {{.*}}ptr [[NAME]](ptr {{.*}}, {{i32|\[1 x i32\]|i64|%struct.ReadWriteIntArray\* byval\(%struct.ReadWriteIntArray\)}}{{.*}})
 // CHECK:   [[THIS:%.*]] = load ptr, ptr
-// CHECK:   [[VALUES:%.*]] = getelementptr inbounds %struct.ReadWriteIntArray, ptr [[THIS]]
+// CHECK:   [[VALUES:%.*]] = getelementptr inbounds{{.*}} %struct.ReadWriteIntArray, ptr [[THIS]]
 // CHECK:   [[VALUE:%.*]] = getelementptr inbounds [5 x {{i32|i64}}], ptr [[VALUES]]
 // CHECK:   ret ptr [[VALUE]]
 
@@ -44,7 +44,7 @@ public func index(_ arr: inout NonTrivialIntArrayByVal, _ arg: Int32) -> Int32 {
 
 // CHECK: define {{.*}}[[RES:i32|i64]] [[NAME]](ptr {{.*}}, {{i32|\[1 x i32\]|i64|%struct.NonTrivialIntArrayByVal\* byval\(%struct.NonTrivialIntArrayByVal\)}}{{.*}})
 // CHECK:   [[THIS:%.*]] = load ptr, ptr
-// CHECK:   [[VALUES:%.*]] = getelementptr inbounds %struct.NonTrivialIntArrayByVal, ptr [[THIS]]
+// CHECK:   [[VALUES:%.*]] = getelementptr inbounds{{.*}} %struct.NonTrivialIntArrayByVal, ptr [[THIS]]
 // CHECK:   [[VALUE:%.*]] = getelementptr inbounds [5 x {{i32|i64}}], ptr [[VALUES]]
 // CHECK:   [[VALUE2:%.*]] = load {{i32|i64}}, ptr [[VALUE]]
 // CHECK:   ret {{i32|i64}} [[VALUE2]]
diff --git a/test/Interop/Cxx/operators/member-inline-module-interface.swift b/test/Interop/Cxx/operators/member-inline-module-interface.swift
index a07a2cf864148..8c5338e5b3439 100644
--- a/test/Interop/Cxx/operators/member-inline-module-interface.swift
+++ b/test/Interop/Cxx/operators/member-inline-module-interface.swift
@@ -1,6 +1,6 @@
-// RUN: %target-swift-ide-test -print-module -module-to-print=MemberInline -I %S/Inputs -source-filename=x -cxx-interoperability-mode=swift-5.9 | %FileCheck %s
-// RUN: %target-swift-ide-test -print-module -module-to-print=MemberInline -I %S/Inputs -source-filename=x -cxx-interoperability-mode=swift-6 | %FileCheck %s
-// RUN: %target-swift-ide-test -print-module -module-to-print=MemberInline -I %S/Inputs -source-filename=x -cxx-interoperability-mode=upcoming-swift | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -module-to-print=MemberInline -I %S/Inputs -source-filename=x -cxx-interoperability-mode=swift-5.9 -Xcc -std=c++23 | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -module-to-print=MemberInline -I %S/Inputs -source-filename=x -cxx-interoperability-mode=swift-6 -Xcc -std=c++23 | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -module-to-print=MemberInline -I %S/Inputs -source-filename=x -cxx-interoperability-mode=upcoming-swift -Xcc -std=c++23 | %FileCheck %s
 
 // CHECK: struct LoadableIntWrapper {
 // CHECK:   func successor() -> LoadableIntWrapper
@@ -58,6 +58,21 @@
 // CHECK:   }
 // CHECK: }
 
+// CHECK: struct NullarySubscript {
+// CHECK:   subscript() -> Int32
+// CHECK:   @available(*, unavailable, message: "use subscript")
+// CHECK:   func __operatorSubscriptConst() -> Int32
+// CHECK:   @available(*, unavailable, message: "use subscript")
+// CHECK:   mutating func __operatorSubscript() -> UnsafeMutablePointer<Int32>
+// CHECK: }
+
+// CHECK: struct BinarySubscript {
+// CHECK:   subscript(x: Int32, y: Int32) -> Int32
+// CHECK:   @available(*, unavailable, message: "use subscript")
+// CHECK:   func __operatorSubscriptConst(_ x: Int32, _ y: Int32) -> Int32
+// CHECK:   @available(*, unavailable, message: "use subscript")
+// CHECK:   mutating func __operatorSubscript(_: Int32, _: Int32) -> UnsafeMutablePointer<Int32>
+// CHECK: }
 
 // CHECK: struct ReadOnlyIntArray {
 // CHECK:   subscript(x: Int32) -> Int32 { get }
@@ -212,10 +227,10 @@
 // CHECK: }
 
 // CHECK: struct SubscriptUnnamedParameter {
-// CHECK:   subscript(__index: Int32) -> Int32 { get }
+// CHECK:   subscript(__index0: Int32) -> Int32 { get }
 // CHECK: }
 // CHECK: struct SubscriptUnnamedParameterReadWrite {
-// CHECK:   subscript(__index: Int32) -> Int32
+// CHECK:   subscript(__index0: Int32) -> Int32
 // CHECK: }
 
 // CHECK: struct Iterator {
diff --git a/test/Interop/Cxx/operators/member-inline-typechecker.swift b/test/Interop/Cxx/operators/member-inline-typechecker.swift
index 7db791a32a60d..e38b921f6d900 100644
--- a/test/Interop/Cxx/operators/member-inline-typechecker.swift
+++ b/test/Interop/Cxx/operators/member-inline-typechecker.swift
@@ -1,6 +1,6 @@
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=swift-5.9
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=swift-6
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=swift-5.9
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=swift-6
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
 
 import MemberInline
 
diff --git a/test/Interop/Cxx/operators/member-inline.swift b/test/Interop/Cxx/operators/member-inline.swift
index 0adc43a2b6377..3212114e22218 100644
--- a/test/Interop/Cxx/operators/member-inline.swift
+++ b/test/Interop/Cxx/operators/member-inline.swift
@@ -1,6 +1,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=swift-5.9)
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=swift-6)
-// RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=upcoming-swift)
+// RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=upcoming-swift -Xcc -std=c++23 -D CPP23)
 //
 // REQUIRES: executable_test
 
@@ -185,6 +185,20 @@ OperatorsTestSuite.test("ReadWriteIntArray.subscript (inline)") {
   expectEqual(234, resultAfter)
 }
 
+#if CPP23
+OperatorsTestSuite.test("Subscript operators with parameter number != 1") {
+  var ns = NullarySubscript()
+  expectEqual(42, ns[])
+  ns[] = 5
+  expectEqual(5, ns.field)
+
+  var bs = BinarySubscript()
+  expectEqual(10, bs[3, 7])
+  bs[1, 2] = 6
+  expectEqual(6, bs.field)
+}
+#endif
+
 OperatorsTestSuite.test("DerivedFromReadWriteIntArray.subscript (inline, base class)") {
   var arr = DerivedFromReadWriteIntArray()
 
diff --git a/test/Interop/Cxx/operators/non-member-inline-module-interface.swift b/test/Interop/Cxx/operators/non-member-inline-module-interface.swift
index 84036976f1fc1..a3f11826642b2 100644
--- a/test/Interop/Cxx/operators/non-member-inline-module-interface.swift
+++ b/test/Interop/Cxx/operators/non-member-inline-module-interface.swift
@@ -6,6 +6,7 @@
 // CHECK-NEXT: func / (lhs: LoadableIntWrapper, rhs: LoadableIntWrapper) -> LoadableIntWrapper
 // CHECK-NEXT: func % (lhs: LoadableIntWrapper, rhs: LoadableIntWrapper) -> LoadableIntWrapper
 // CHECK-NEXT: func ^ (lhs: LoadableIntWrapper, rhs: LoadableIntWrapper) -> LoadableIntWrapper
+// CHECK-NEXT: func ~ (lhs: LoadableIntWrapper) -> LoadableIntWrapper
 // CHECK-NEXT: func & (lhs: LoadableIntWrapper, rhs: LoadableIntWrapper) -> LoadableIntWrapper
 // CHECK-NEXT: func | (lhs: LoadableIntWrapper, rhs: LoadableIntWrapper) -> LoadableIntWrapper
 // CHECK-NEXT: func << (lhs: LoadableIntWrapper, rhs: LoadableIntWrapper) -> LoadableIntWrapper
@@ -19,3 +20,7 @@
 
 // CHECK:      func && (lhs: LoadableBoolWrapper, rhs: LoadableBoolWrapper) -> LoadableBoolWrapper
 // CHECK-NEXT: func || (lhs: LoadableBoolWrapper, rhs: LoadableBoolWrapper) -> LoadableBoolWrapper
+
+// CHECK-NOT:  func + (lhs: RValueArithmetic
+
+// CHECK:      func + (lhs: LValueAndRValueArithmetic, rhs: LValueAndRValueArithmetic) -> LValueAndRValueArithmetic
diff --git a/test/Interop/Cxx/operators/non-member-inline-typechecker.swift b/test/Interop/Cxx/operators/non-member-inline-typechecker.swift
index bc02abab94c4a..ed61c93a13d1c 100644
--- a/test/Interop/Cxx/operators/non-member-inline-typechecker.swift
+++ b/test/Interop/Cxx/operators/non-member-inline-typechecker.swift
@@ -37,3 +37,11 @@ var rhsBool = LoadableBoolWrapper(value: false)
 
 let resultAmpAmp = lhsBool && rhsBool
 let resultPipePipe = lhsBool && rhsBool
+
+let lhsRValue = RValueArithmetic(value: 123)
+let rhsRValue = RValueArithmetic(value: 146)
+let resultRValue = lhsRValue + rhsRValue // expected-error {{binary operator '+' cannot be applied to two 'RValueArithmetic' operands}}
+
+let lhsLRValue = LValueAndRValueArithmetic(value: 123)
+let rhsLRValue = LValueAndRValueArithmetic(value: 146)
+let resultLRValue = lhsLRValue + rhsLRValue
diff --git a/test/Interop/Cxx/operators/non-member-inline.swift b/test/Interop/Cxx/operators/non-member-inline.swift
index 6b6bcb6b6cc22..1132ff1728ce0 100644
--- a/test/Interop/Cxx/operators/non-member-inline.swift
+++ b/test/Interop/Cxx/operators/non-member-inline.swift
@@ -52,6 +52,14 @@ OperatorsTestSuite.test("caret (^)") {
   expectEqual(61, result.value)
 }
 
+OperatorsTestSuite.test("tilde (~)") {
+  let lhs = LoadableIntWrapper(value: 42)
+
+  let result = ~lhs
+
+  expectEqual(-43, result.value)
+}
+
 OperatorsTestSuite.test("percent (%)") {
   let lhs = LoadableIntWrapper(value: 11)
   let rhs = LoadableIntWrapper(value: 2)
@@ -193,4 +201,11 @@ OperatorsTestSuite.test("UnnamedParameterInOperator.equal") {
   expectFalse(lhs == rhs)
 }
 
+OperatorsTestSuite.test("LValueAndRValueArithmetic.+") {
+  let lhs = LValueAndRValueArithmetic(value: 123)
+  let rhs = LValueAndRValueArithmetic(value: 146)
+
+  expectEqual(269, (lhs + rhs).value)
+}
+
 runAllTests()
diff --git a/test/Interop/Cxx/reference/reference-cannot-import-diagnostic.swift b/test/Interop/Cxx/reference/reference-cannot-import-diagnostic.swift
index 48e1b3e45ef0d..1510aa3265e27 100644
--- a/test/Interop/Cxx/reference/reference-cannot-import-diagnostic.swift
+++ b/test/Interop/Cxx/reference/reference-cannot-import-diagnostic.swift
@@ -1,6 +1,6 @@
 // RUN: rm -rf %t
 // RUN: split-file %s %t
-// RUN: %target-swift-frontend -typecheck -verify -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop
 // RUN: not %target-swift-frontend -typecheck -I %t/Inputs  %t/test.swift  -enable-experimental-cxx-interop 2>&1 | %FileCheck %s
 
 //--- Inputs/module.modulemap
diff --git a/test/Interop/Cxx/reference/reference.swift b/test/Interop/Cxx/reference/reference.swift
index 70ffe95a3191b..9478a4f003ff0 100644
--- a/test/Interop/Cxx/reference/reference.swift
+++ b/test/Interop/Cxx/reference/reference.swift
@@ -103,4 +103,9 @@ ReferenceTestSuite.test("const reference to template") {
   expectEqual(53, ref.pointee)
 }
 
+ReferenceTestSuite.test("rvalue reference of trivial type") {
+  setStaticIntRvalueRef(consuming: 2)
+  expectEqual(2, getStaticInt())
+}
+
 runAllTests()
diff --git a/test/Interop/Cxx/static/inline-static-member-var-irgen.swift b/test/Interop/Cxx/static/inline-static-member-var-irgen.swift
index f5409c05e9864..820d6962b3353 100644
--- a/test/Interop/Cxx/static/inline-static-member-var-irgen.swift
+++ b/test/Interop/Cxx/static/inline-static-member-var-irgen.swift
@@ -28,4 +28,4 @@ public func passingVarAsInout() {
 }
 
 // CHECK: define {{(protected |dllexport )?}}swiftcc void @"$s4main17passingVarAsInoutyyF"()
-// CHECK: call swiftcc void @"$s4main11modifyInoutyys5Int32VzF"(ptr nocapture dereferenceable(4) @{{_ZN22WithInlineStaticMember12staticMemberE|"\?staticMember@WithInlineStaticMember@@2HA"}})
+// CHECK: call swiftcc void @"$s4main11modifyInoutyys5Int32VzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable(4) @{{_ZN22WithInlineStaticMember12staticMemberE|"\?staticMember@WithInlineStaticMember@@2HA"}})
diff --git a/test/Interop/Cxx/static/static-member-var-irgen.swift b/test/Interop/Cxx/static/static-member-var-irgen.swift
index 25c77d3ef38f4..8b8c2cdcffd15 100644
--- a/test/Interop/Cxx/static/static-member-var-irgen.swift
+++ b/test/Interop/Cxx/static/static-member-var-irgen.swift
@@ -45,8 +45,8 @@ public func readDefinedConstMember() -> CInt {
 }
 
 // CHECK: define {{(protected |dllexport )?}}swiftcc i32 @"$s4main22readDefinedConstMembers5Int32VyF"() #0
-// CHECK: [[VALUE:%.*]] = load i32, ptr @{{_ZN21WithConstStaticMember7definedE|"\?defined@WithConstStaticMember@@2HB"}}, align 4
-// CHECK: ret i32 [[VALUE]]
+// CHECK: ret i32 48
+
 public func readDefinedOutOfLineConstMember() -> CInt {
   return WithConstStaticMember.definedOutOfLine
 }
diff --git a/test/Interop/Cxx/static/static-member-var-silgen.swift b/test/Interop/Cxx/static/static-member-var-silgen.swift
index 3df7d9c290e26..6d81208309e61 100644
--- a/test/Interop/Cxx/static/static-member-var-silgen.swift
+++ b/test/Interop/Cxx/static/static-member-var-silgen.swift
@@ -56,9 +56,10 @@ func readDefinedConstMember() -> CInt {
 }
 
 // CHECK: sil hidden @$s4main22readDefinedConstMembers5Int32VyF : $@convention(thin) () -> Int32
-// CHECK: [[ADDR:%.*]] = global_addr @{{_ZN21WithConstStaticMember7definedE|\?defined@WithConstStaticMember@@2HB}} : $*Int32
-// CHECK: [[VALUE:%.*]] = load [[ADDR]] : $*Int32
-// CHECK: return [[VALUE]] : $Int32
+// CHECK: [[VALUE:%.*]] = integer_literal $Builtin.Int32, 48
+// CHECK: [[STRUCT:%.*]] = struct $Int32 ([[VALUE]] : $Builtin.Int32)
+// CHECK: return [[STRUCT]] : $Int32
+
 func readDefinedOutOfLineConstMember() -> CInt {
   return WithConstStaticMember.definedOutOfLine
 }
\ No newline at end of file
diff --git a/test/Interop/Cxx/static/static-var-irgen.swift b/test/Interop/Cxx/static/static-var-irgen.swift
index 25bc2f33ff741..2fe8d1f1f43e7 100644
--- a/test/Interop/Cxx/static/static-var-irgen.swift
+++ b/test/Interop/Cxx/static/static-var-irgen.swift
@@ -10,7 +10,6 @@ public func initStaticVars() -> CInt {
 // CHECK: @{{_ZL9staticVar|staticVar}} = internal global i32 2, align 4
 // CHECK: @{{_ZL13staticVarInit|staticVarInit}} = internal global i32 0, align 4
 // CHECK: @{{_ZL19staticVarInlineInit|staticVarInlineInit}} = internal global i32 0, align 4
-// CHECK: @{{_ZL11staticConst|staticConst}} = internal constant i32 4, align 4
 // CHECK: @{{_ZL15staticConstInit|staticConstInit}} = internal global i32 0, align 4
 // CHECK: @{{_ZL21staticConstInlineInit|staticConstInlineInit}} = internal global i32 0, align 4
 // CHECK: @{{_ZL16staticNonTrivial|staticNonTrivial}} = internal global %class.NonTrivial zeroinitializer, align 4
@@ -86,7 +85,7 @@ public func passingVarAsInout() {
   modifyInout(&staticVar)
 }
 // CHECK: define {{.*}}void @"$s4main17passingVarAsInoutyyF"()
-// CHECK: call swiftcc void @"$s4main11modifyInoutyys5Int32VzF"(ptr nocapture dereferenceable(4) @{{_ZL9staticVar|staticVar}})
+// CHECK: call swiftcc void @"$s4main11modifyInoutyys5Int32VzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable(4) @{{_ZL9staticVar|staticVar}})
 
 // CHECK: define internal void @_GLOBAL__sub_I__swift_imported_modules_()
 // CHECK: call void @{{__cxx_global_var_init|"\?\?__EstaticVarInit@@YAXXZ"}}()
diff --git a/test/Interop/Cxx/static/static-var-silgen.swift b/test/Interop/Cxx/static/static-var-silgen.swift
index 551c241d98820..dd85893a5e96d 100644
--- a/test/Interop/Cxx/static/static-var-silgen.swift
+++ b/test/Interop/Cxx/static/static-var-silgen.swift
@@ -13,8 +13,6 @@ func initStaticVars() -> CInt {
 // CHECK: sil_global public_external @staticVarInit : $Int32
 // CHECK: // clang name: staticVarInlineInit
 // CHECK: sil_global public_external @staticVarInlineInit : $Int32
-// CHECK: // clang name: staticConst
-// CHECK: sil_global public_external [let] @staticConst : $Int32
 // CHECK: // clang name: staticConstInit
 // CHECK: sil_global public_external [let] @staticConstInit : $Int32
 // CHECK: // clang name: staticConstInlineInit
@@ -24,6 +22,14 @@ func initStaticVars() -> CInt {
 // CHECK: // clang name: staticConstNonTrivial
 // CHECK: sil_global public_external [let] @staticConstNonTrivial : $NonTrivial
 
+// CHECK: // staticConst.getter
+// CHECK: sil shared [transparent] @$sSo11staticConsts5Int32Vvg : $@convention(thin) () -> Int32 {
+// CHECK: bb0:
+// CHECK:   %0 = integer_literal $Builtin.Int32, 4
+// CHECK:   %1 = struct $Int32 (%0 : $Builtin.Int32)
+// CHECK:   return %1 : $Int32
+// CHECK: }
+
 func readStaticVar() -> CInt {
   return staticVar
 }
diff --git a/test/Interop/Cxx/stdlib/Inputs/check-libcxx-version.cpp b/test/Interop/Cxx/stdlib/Inputs/check-libcxx-version.cpp
index 87f848f8f718c..8d14bee63e967 100644
--- a/test/Interop/Cxx/stdlib/Inputs/check-libcxx-version.cpp
+++ b/test/Interop/Cxx/stdlib/Inputs/check-libcxx-version.cpp
@@ -6,7 +6,9 @@ int main() {
   return 1;
 #endif
 
-#if _LIBCPP_VERSION >= 170004
+  // the libc++ module was split into multiple top-level modules in Clang 17,
+  // and then re-merged into one module with submodules in Clang 20
+#if _LIBCPP_VERSION >= 170004 && _LIBCPP_VERSION < 200000
   return 0;
 #else
   return 1;
diff --git a/test/Interop/Cxx/stdlib/Inputs/custom-smart-ptr.h b/test/Interop/Cxx/stdlib/Inputs/custom-smart-ptr.h
new file mode 100644
index 0000000000000..617b728fb79d7
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/Inputs/custom-smart-ptr.h
@@ -0,0 +1,22 @@
+#pragma once
+
+static int copies2 = 0;
+
+struct CountCopies2 {
+  CountCopies2() = default;
+  CountCopies2(const CountCopies2& other) { ++copies2; }
+  ~CountCopies2() {}
+
+  int getCopies() const { return copies2; }
+  void method() {}
+  void constMethod() const {}
+  int field = 42;
+};
+
+struct MySmartPtr {
+    CountCopies2& operator*() const [[clang::lifetimebound]] { return *ptr; }
+
+    CountCopies2* ptr;
+};
+
+inline MySmartPtr getPtr() { return MySmartPtr{new CountCopies2()}; }
diff --git a/test/Interop/Cxx/stdlib/Inputs/module.modulemap b/test/Interop/Cxx/stdlib/Inputs/module.modulemap
index 57f7eae3bb670..0ca81ec0670af 100644
--- a/test/Interop/Cxx/stdlib/Inputs/module.modulemap
+++ b/test/Interop/Cxx/stdlib/Inputs/module.modulemap
@@ -81,3 +81,9 @@ module NoCXXStdlib {
   requires cplusplus
   export *
 }
+
+module CustomSmartPtr {
+  header "custom-smart-ptr.h"
+  requires cplusplus
+  export *
+}
diff --git a/test/Interop/Cxx/stdlib/Inputs/std-map.h b/test/Interop/Cxx/stdlib/Inputs/std-map.h
index e9275232ef1b5..d28739869947d 100644
--- a/test/Interop/Cxx/stdlib/Inputs/std-map.h
+++ b/test/Interop/Cxx/stdlib/Inputs/std-map.h
@@ -17,4 +17,14 @@ inline UnorderedMap initUnorderedMap() { return {{1, 3}, {3, 3}, {2, 2}}; }
 inline Map initEmptyMap() { return {}; }
 inline UnorderedMap initEmptyUnorderedMap() { return {}; }
 
+struct NonCopyable {
+  NonCopyable() = default;
+  NonCopyable(const NonCopyable &other) = delete;
+  NonCopyable(NonCopyable &&other) = default;
+  ~NonCopyable() {}
+};
+
+using MapNonCopyableKey = std::map<NonCopyable, int>;
+using MapNonCopyableValue = std::map<int, NonCopyable>;
+
 #endif // TEST_INTEROP_CXX_STDLIB_INPUTS_STD_MAP_H
diff --git a/test/Interop/Cxx/stdlib/Inputs/std-optional.h b/test/Interop/Cxx/stdlib/Inputs/std-optional.h
index 98a07c12ac278..dd7c45bd5c140 100644
--- a/test/Interop/Cxx/stdlib/Inputs/std-optional.h
+++ b/test/Interop/Cxx/stdlib/Inputs/std-optional.h
@@ -5,13 +5,44 @@
 #include <string>
 
 using StdOptionalInt = std::optional<int>;
+using StdOptionalBool = std::optional<bool>;
 using StdOptionalString = std::optional<std::string>;
+using StdOptionalOptionalInt = std::optional<std::optional<int>>;
+
+struct HasConstexprCtor {
+  int value;
+  constexpr HasConstexprCtor(int value) : value(value) {}
+  constexpr HasConstexprCtor(const HasConstexprCtor &other) = default;
+  constexpr HasConstexprCtor(HasConstexprCtor &&other) = default;
+};
+using StdOptionalHasConstexprCtor = std::optional<HasConstexprCtor>;
+
+struct HasDeletedCopyCtor {
+  int value;
+  HasDeletedCopyCtor(int value) : value(value) {}
+  HasDeletedCopyCtor(const HasDeletedCopyCtor &other) = delete;
+  HasDeletedCopyCtor(HasDeletedCopyCtor &&other) = default;
+};
+using StdOptionalHasDeletedCopyCtor = std::optional<HasDeletedCopyCtor>;
+
+struct HasDeletedMoveCtor {
+  int value;
+  HasDeletedMoveCtor(int value) : value(value) {}
+  HasDeletedMoveCtor(const HasDeletedMoveCtor &other) : value(other.value) {}
+  HasDeletedMoveCtor(HasDeletedMoveCtor &&other) = delete;
+};
+using StdOptionalHasDeletedMoveCtor = std::optional<HasDeletedMoveCtor>;
 
 inline StdOptionalInt getNonNilOptional() { return {123}; }
 
 inline StdOptionalInt getNilOptional() { return {std::nullopt}; }
 
+inline StdOptionalHasDeletedCopyCtor getNonNilOptionalHasDeletedCopyCtor() {
+  return StdOptionalHasDeletedCopyCtor(HasDeletedCopyCtor(654));
+}
+
 inline bool takesOptionalInt(std::optional<int> arg) { return (bool)arg; }
 inline bool takesOptionalString(std::optional<std::string> arg) { return (bool)arg; }
+inline bool takesOptionalHasDeletedCopyCtor(std::optional<HasDeletedCopyCtor> arg) { return (bool)arg; }
 
 #endif // TEST_INTEROP_CXX_STDLIB_INPUTS_STD_OPTIONAL_H
diff --git a/test/Interop/Cxx/stdlib/Inputs/std-set.h b/test/Interop/Cxx/stdlib/Inputs/std-set.h
index e48ed78dafb0a..b66e10f3fba06 100644
--- a/test/Interop/Cxx/stdlib/Inputs/std-set.h
+++ b/test/Interop/Cxx/stdlib/Inputs/std-set.h
@@ -12,4 +12,13 @@ inline SetOfCInt initSetOfCInt() { return {1, 5, 3}; }
 inline UnorderedSetOfCInt initUnorderedSetOfCInt() { return {2, 4, 6}; }
 inline MultisetOfCInt initMultisetOfCInt() { return {2, 2, 4, 6}; }
 
+struct NonCopyable {
+  NonCopyable() = default;
+  NonCopyable(const NonCopyable &other) = delete;
+  NonCopyable(NonCopyable &&other) = default;
+  ~NonCopyable() {}
+};
+
+using SetOfNonCopyable = std::set<NonCopyable>;
+
 #endif // TEST_INTEROP_CXX_STDLIB_INPUTS_STD_SET_H
diff --git a/test/Interop/Cxx/stdlib/Inputs/std-span.h b/test/Interop/Cxx/stdlib/Inputs/std-span.h
index b02c869d88cf7..2657dec2ccbdc 100644
--- a/test/Interop/Cxx/stdlib/Inputs/std-span.h
+++ b/test/Interop/Cxx/stdlib/Inputs/std-span.h
@@ -165,9 +165,20 @@ inline SpanOfInt MixedFuncWithMutableSafeWrapper7(int * __counted_by(len) p, int
   return SpanOfInt(p, len);
 }
 
+template <typename X>
+struct S {};
+
 struct SpanWithoutTypeAlias {
   std::span<const int> bar() [[clang::lifetimebound]];
   void foo(std::span<const int> s [[clang::noescape]]);
+  void otherTemplatedType(ConstSpanOfInt copy [[clang::noescape]], S<int>);
+  void otherTemplatedType2(ConstSpanOfInt copy [[clang::noescape]], S<int> *);
 };
 
+inline void func(ConstSpanOfInt copy [[clang::noescape]]) {}
+inline void mutableKeyword(SpanOfInt copy [[clang::noescape]]) {}
+
+inline void spanWithoutTypeAlias(std::span<const int> s [[clang::noescape]]) {}
+inline void mutableSpanWithoutTypeAlias(std::span<int> s [[clang::noescape]]) {}
+
 #endif // TEST_INTEROP_CXX_STDLIB_INPUTS_STD_SPAN_H
diff --git a/test/Interop/Cxx/stdlib/Inputs/std-string-and-vector.h b/test/Interop/Cxx/stdlib/Inputs/std-string-and-vector.h
index 610f86f7a217c..77a11ae77144c 100644
--- a/test/Interop/Cxx/stdlib/Inputs/std-string-and-vector.h
+++ b/test/Interop/Cxx/stdlib/Inputs/std-string-and-vector.h
@@ -9,3 +9,28 @@ struct Item {
 inline Item get_item() {
   return {};
 }
+
+std::vector<int> makeVecOfInt() { return {1, 2, 3}; }
+std::vector<std::string> makeVecOfString() { return {"Hello", "World"}; }
+
+struct S {
+private:
+  std::string privStr;
+  std::vector<std::string> privVec;
+
+public:
+  std::string pubStr;
+  std::vector<std::string> pubVec;
+
+protected:
+  std::string protStr;
+  std::vector<std::string> protVec;
+
+public:
+  S() : privStr("private"), privVec({"private", "vector"}), 
+        pubStr("public"), pubVec({"a", "public", "vector"}), 
+        protStr("protected"), protVec({"protected", "vector"}) {}
+
+  std::vector<std::string> getPrivVec() const { return privVec; }
+  std::string getProtStr() const { return protStr; }
+};
diff --git a/test/Interop/Cxx/stdlib/Inputs/std-string.h b/test/Interop/Cxx/stdlib/Inputs/std-string.h
index 62de38a035e83..68423dbd70cf9 100644
--- a/test/Interop/Cxx/stdlib/Inputs/std-string.h
+++ b/test/Interop/Cxx/stdlib/Inputs/std-string.h
@@ -6,3 +6,15 @@ struct HasMethodThatReturnsString {
 };
 
 inline std::string takesStringWithDefaultArg(std::string s = "abc") { return s; }
+
+struct StringBox {
+  std::string value;
+
+  friend bool operator==(const StringBox &lhs, const std::string &rhs) {
+    return lhs.value == rhs;
+  }
+
+  friend bool operator==(const std::string &lhs, const StringBox &rhs) {
+    return rhs == lhs;
+  }
+};
diff --git a/test/Interop/Cxx/stdlib/Inputs/std-unique-ptr.h b/test/Interop/Cxx/stdlib/Inputs/std-unique-ptr.h
index 428478777c4a6..e6cc6bf0d5ca0 100644
--- a/test/Interop/Cxx/stdlib/Inputs/std-unique-ptr.h
+++ b/test/Interop/Cxx/stdlib/Inputs/std-unique-ptr.h
@@ -2,6 +2,8 @@
 #define TEST_INTEROP_CXX_STDLIB_INPUTS_STD_UNIQUE_PTR_H
 
 #include <memory>
+#include <string>
+#include <vector>
 
 struct NonCopyable {
     NonCopyable(int x) : x(x) {}
@@ -25,10 +27,21 @@ struct NonCopyableDerived: public NonCopyable {
 inline std::shared_ptr<NonCopyable> getNonCopyableSharedPtr() { return std::make_shared<NonCopyableDerived>(42); }
 inline std::unique_ptr<NonCopyable> getNonCopyableUniquePtr() { return std::make_unique<NonCopyableDerived>(42); }
 
+inline std::vector<std::unique_ptr<NonCopyable>>
+getVectorNonCopyableUniquePtr() {
+  std::vector<std::unique_ptr<NonCopyable>> vec;
+  vec.emplace_back();
+  return vec;
+}
+
 std::unique_ptr<int> makeInt() {
   return std::make_unique<int>(42);
 }
 
+std::unique_ptr<std::string> makeString() {
+  return std::make_unique<std::string>("Unique string");
+}
+
 std::unique_ptr<int[]> makeArray() {
   int *array = new int[3];
   array[0] = 1;
@@ -55,4 +68,25 @@ std::unique_ptr<HasDtor> makeDtor() {
   return std::make_unique<HasDtor>();
 }
 
+std::shared_ptr<int> makeIntShared() { return std::make_unique<int>(42); }
+
+std::shared_ptr<std::string> makeStringShared() {
+  return std::make_unique<std::string>("Shared string");
+}
+
+static int copies = 0;
+
+struct CountCopies {
+  CountCopies() = default;
+  CountCopies(const CountCopies& other) { ++copies; }
+  ~CountCopies() {}
+
+  int getCopies() const { return copies; }
+  void method() {}
+  void constMethod() const {}
+  int field = 42;
+};
+
+inline std::unique_ptr<CountCopies> getCopyCountedUniquePtr() { return std::make_unique<CountCopies>(); }
+
 #endif // TEST_INTEROP_CXX_STDLIB_INPUTS_STD_UNIQUE_PTR_H
diff --git a/test/Interop/Cxx/stdlib/Inputs/std-vector.h b/test/Interop/Cxx/stdlib/Inputs/std-vector.h
index e562a8227f8d6..4d70fec7c78ad 100644
--- a/test/Interop/Cxx/stdlib/Inputs/std-vector.h
+++ b/test/Interop/Cxx/stdlib/Inputs/std-vector.h
@@ -1,8 +1,8 @@
 #ifndef TEST_INTEROP_CXX_STDLIB_INPUTS_STD_VECTOR_H
 #define TEST_INTEROP_CXX_STDLIB_INPUTS_STD_VECTOR_H
 
-#include <vector>
 #include <string>
+#include <vector>
 
 using Vector = std::vector<int>;
 using VectorOfString = std::vector<std::string>;
@@ -22,4 +22,22 @@ class VectorOfStringSubclass : public std::vector<std::string> {
   using std::vector<std::string>::vector;
 };
 
+struct __attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:immortal")))
+__attribute__((swift_attr("release:immortal"))) ImmortalRef {
+  int value;
+  static ImmortalRef *create(int value) { return new ImmortalRef({value}); }
+};
+using VectorOfImmortalRefPtr = std::vector<ImmortalRef *>;
+
+struct NonCopyable {
+  NonCopyable() = default;
+  NonCopyable(const NonCopyable &other) = delete;
+  NonCopyable(NonCopyable &&other) = default;
+  ~NonCopyable() {}
+};
+
+using VectorOfNonCopyable = std::vector<NonCopyable>;
+using VectorOfPointer = std::vector<NonCopyable *>;
+
 #endif // TEST_INTEROP_CXX_STDLIB_INPUTS_STD_VECTOR_H
diff --git a/test/Interop/Cxx/stdlib/avoid-import-cxx-math.swift b/test/Interop/Cxx/stdlib/avoid-import-cxx-math.swift
index 325640ee20bcb..c13588aa98ce2 100644
--- a/test/Interop/Cxx/stdlib/avoid-import-cxx-math.swift
+++ b/test/Interop/Cxx/stdlib/avoid-import-cxx-math.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend %s -typecheck -verify -cxx-interoperability-mode=swift-6
 // RUN: %target-swift-frontend %s -typecheck -verify -cxx-interoperability-mode=upcoming-swift
 
-// REQUIRES: OS=macosx || OS=linux-gnu
+// REQUIRES: OS=macosx || OS=linux-gnu || OS=freebsd
 
 import CxxStdlib
 
diff --git a/test/Interop/Cxx/stdlib/avoid-redundant-copies.swift b/test/Interop/Cxx/stdlib/avoid-redundant-copies.swift
new file mode 100644
index 0000000000000..6ee02fc37931b
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/avoid-redundant-copies.swift
@@ -0,0 +1,40 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=upcoming-swift)
+
+// REQUIRES: executable_test
+
+// https://github.com/apple/swift/issues/70226
+// UNSUPPORTED: OS=windows-msvc
+
+import StdlibUnittest
+import StdUniquePtr
+import CustomSmartPtr
+import CxxStdlib
+
+var AvoidCopiesSuite = TestSuite("AvoidRedundantCopies")
+
+AvoidCopiesSuite.test("The pointee does not copy when passed as self") {
+  let up = getNonCopyableUniquePtr()
+  expectEqual(up.pointee.method(1), 42)
+  expectEqual(up.pointee.method(1), 42)
+  let cup = getCopyCountedUniquePtr();
+  expectEqual(cup.pointee.getCopies(), 0)
+  cup.pointee.method()
+  cup.pointee.constMethod()
+  let _ = cup.pointee.field
+  expectEqual(cup.pointee.getCopies(), 0)
+  let copy = cup.pointee
+  expectEqual(copy.getCopies(), 1)
+}
+
+AvoidCopiesSuite.test("The custom smart pointer pointee does not copy when passed as self") {
+  let myptr = getPtr();
+  expectEqual(myptr.pointee.getCopies(), 0)
+  myptr.pointee.method()
+  myptr.pointee.constMethod()
+  let _ = myptr.pointee.field
+  expectEqual(myptr.pointee.getCopies(), 0)
+  let copy = myptr.pointee
+  expectEqual(copy.getCopies(), 1)
+}
+
+runAllTests()
diff --git a/test/Interop/Cxx/stdlib/custom-expressible-by-string-literal.swift b/test/Interop/Cxx/stdlib/custom-expressible-by-string-literal.swift
new file mode 100644
index 0000000000000..2de6173b1e8fa
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/custom-expressible-by-string-literal.swift
@@ -0,0 +1,22 @@
+// RUN: %target-swift-emit-silgen -verify -I %S/Inputs -cxx-interoperability-mode=upcoming-swift %s | %FileCheck %s
+
+import CxxStdlib
+import StdString
+
+extension StringBox: @retroactive ExpressibleByStringLiteral {
+  public init(stringLiteral value: String) {
+    self.value = std.string(value)
+  }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s4main4testyyF
+// CHECK: // function_ref static std{{.*}}basic_string<CChar, std{{.*}}char_traits<CChar>, std{{.*}}allocator<CChar>>.== infix(_:_:)
+// CHECK: // function_ref static std{{.*}}basic_string<CChar, std{{.*}}char_traits<CChar>, std{{.*}}allocator<CChar>>.== infix(_:_:)
+// CHECK: // function_ref static String.== infix(_:_:)
+// CHECK: } // end sil function '$s4main4testyyF'
+func test() {
+  let cxxString: std.string = ""
+  let _ = cxxString == "def" // Ok
+  let _ = "def" == cxxString // Ok
+  let _ = "def" == "hello" // Ok
+}
diff --git a/test/Interop/Cxx/stdlib/fake-toolchain-module-interface.swift b/test/Interop/Cxx/stdlib/fake-toolchain-module-interface.swift
index 9fbab5154011c..f70b8ae1c02ad 100644
--- a/test/Interop/Cxx/stdlib/fake-toolchain-module-interface.swift
+++ b/test/Interop/Cxx/stdlib/fake-toolchain-module-interface.swift
@@ -5,6 +5,7 @@
 // Android NDK layout might need more flags to find libc++
 // XFAIL: OS=linux-androideabi
 // XFAIL: OS=linux-android
+// XFAIL: OS=freebsd
 
 // CHECK: enum FakeNamespace {
 // CHECK:   static func foo(_ x: Int32)
diff --git a/test/Interop/Cxx/stdlib/libcxx-module-interface.swift b/test/Interop/Cxx/stdlib/libcxx-module-interface.swift
index 98a90f9c17cc0..70f64aad56ba4 100644
--- a/test/Interop/Cxx/stdlib/libcxx-module-interface.swift
+++ b/test/Interop/Cxx/stdlib/libcxx-module-interface.swift
@@ -1,4 +1,4 @@
-// Only run this test with older libc++, before the top-level std module got split into multiple top-level modules.
+// Don't run this test with libc++ versions 17-19, when the top-level std module was split into multiple top-level modules.
 // RUN: %empty-directory(%t)
 // RUN: %target-clangxx %S/Inputs/check-libcxx-version.cpp -o %t/check-libcxx-version
 // RUN: %target-codesign %t/check-libcxx-version
diff --git a/test/Interop/Cxx/stdlib/libcxx-symbolic-module-interface.swift b/test/Interop/Cxx/stdlib/libcxx-symbolic-module-interface.swift
deleted file mode 100644
index 7a9b0739c074c..0000000000000
--- a/test/Interop/Cxx/stdlib/libcxx-symbolic-module-interface.swift
+++ /dev/null
@@ -1,30 +0,0 @@
-// Only run this test with older libc++, before the top-level std module got split into multiple top-level modules.
-// RUN: %empty-directory(%t)
-// RUN: %target-clangxx %S/Inputs/check-libcxx-version.cpp -o %t/check-libcxx-version
-// RUN: %target-codesign %t/check-libcxx-version
-
-// RUN: %target-swift-ide-test -print-module -module-to-print=CxxStdlib -source-filename=x -enable-experimental-cxx-interop -enable-objc-interop -module-print-submodules -enable-experimental-feature ImportSymbolicCXXDecls > %t/result.txt
-// RUN: %target-run %t/check-libcxx-version || %FileCheck %s --check-prefixes=CHECK,VECTOR --input-file=%t/result.txt
-// RUN: %target-run %t/check-libcxx-version || %FileCheck %s --check-prefixes=CHECK,STRING --input-file=%t/result.txt
-// RUN: %target-run %t/check-libcxx-version || %FileCheck %s --check-prefixes=CHECK,MAP --input-file=%t/result.txt
-
-// REQUIRES: OS=macosx
-// REQUIRES: swift_feature_ImportSymbolicCXXDecls
-
-// Since this test runs check-libcxx-version, it requires execution.
-// REQUIRES: executable_test
-
-// CHECK: enum std {
-// CHECK: enum __1 {
-
-// STRING: struct basic_string {
-
-// STRING: typealias string = std.__1.basic_string
-
-// VECTOR: struct vector {
-// VECTOR: mutating func push_back(_ __x: Any)
-// VECTOR: }
-
-// MAP: struct map {
-
-// CHECK-NOT: enum std
diff --git a/test/Interop/Cxx/stdlib/msvc-abi-use-vector-iterator.swift b/test/Interop/Cxx/stdlib/msvc-abi-use-vector-iterator.swift
index daa43eeb78a59..7972ae2b6bfc5 100644
--- a/test/Interop/Cxx/stdlib/msvc-abi-use-vector-iterator.swift
+++ b/test/Interop/Cxx/stdlib/msvc-abi-use-vector-iterator.swift
@@ -5,7 +5,7 @@
 
 import MsvcUseVecIt
 
-// CHECK:   call void @"?begin@?$vector@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@@std@@QEBA?AV?$_Vector_const_iterator@V?$_Vector_val@U?$_Simple_types@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@std@@@std@@@2@XZ"(ptr {{.*}}, ptr noalias nocapture sret
+// CHECK:   call void @"?begin@?$vector@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@@std@@QEBA?AV?$_Vector_const_iterator@V?$_Vector_val@U?$_Simple_types@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@std@@@std@@@2@XZ"(ptr {{.*}}, ptr noalias{{( nocapture)?}} sret{{( captures\(none\))?}}
 
 func test() -> Bool {
     let result = f()
diff --git a/test/Interop/Cxx/stdlib/msvcprt-module-interface.swift b/test/Interop/Cxx/stdlib/msvcprt-module-interface.swift
index 63dd1a39e515c..3fbd3be898749 100644
--- a/test/Interop/Cxx/stdlib/msvcprt-module-interface.swift
+++ b/test/Interop/Cxx/stdlib/msvcprt-module-interface.swift
@@ -15,8 +15,9 @@
 // CHECK-STRING:   struct basic_string<CChar, std.char_traits<CChar>, std.allocator<CChar>> : CxxRandomAccessCollection {
 // CHECK-STRING:     typealias value_type = CChar
 // CHECK-STRING:   }
-// CHECK-STRING:   struct basic_string<CWideChar, std.char_traits<CWideChar>, std.allocator<CWideChar>> : CxxRandomAccessCollection {
-// CHECK-STRING:     typealias value_type = CWideChar
+// CHECK-STRING:   struct basic_string<CChar16, std.char_traits<CChar16>, std.allocator<CChar16>> : CxxRandomAccessCollection {
+// CHECK-STRING:     typealias value_type = UInt16
+// FIXME: why the value type is different from CChar16?
 // CHECK-STRING:   }
 // CHECK-STRING:   typealias string = std.basic_string<CChar, std.char_traits<CChar>, std.allocator<CChar>>
 // CHECK-STRING:   typealias wstring = std.basic_string<CWideChar, std.char_traits<CWideChar>, std.allocator<CWideChar>>
diff --git a/test/Interop/Cxx/stdlib/overlay/convertible-to-bool-typechecker.swift b/test/Interop/Cxx/stdlib/overlay/convertible-to-bool-typechecker.swift
index 38867db05b77a..669763c6ca1e2 100644
--- a/test/Interop/Cxx/stdlib/overlay/convertible-to-bool-typechecker.swift
+++ b/test/Interop/Cxx/stdlib/overlay/convertible-to-bool-typechecker.swift
@@ -1,6 +1,6 @@
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -enable-experimental-cxx-interop
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=swift-6
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -enable-experimental-cxx-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=swift-6
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
 
 import ConvertibleToBool
 
diff --git a/test/Interop/Cxx/stdlib/overlay/custom-collection.swift b/test/Interop/Cxx/stdlib/overlay/custom-collection.swift
index 6ddadc1fc4420..1534f07d808c3 100644
--- a/test/Interop/Cxx/stdlib/overlay/custom-collection.swift
+++ b/test/Interop/Cxx/stdlib/overlay/custom-collection.swift
@@ -1,4 +1,4 @@
-// REQUIRES: rdar143950805
+// REQUIRES: rdar156235951
 
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop)
 // RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=swift-6)
diff --git a/test/Interop/Cxx/stdlib/overlay/custom-sequence.swift b/test/Interop/Cxx/stdlib/overlay/custom-sequence.swift
index 7f6ca4e0b6315..b9e2572845c7c 100644
--- a/test/Interop/Cxx/stdlib/overlay/custom-sequence.swift
+++ b/test/Interop/Cxx/stdlib/overlay/custom-sequence.swift
@@ -1,7 +1,7 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop)
 //
 // REQUIRES: executable_test
-// REQUIRES: OS=macosx || OS=linux-gnu
+// REQUIRES: OS=macosx || OS=linux-gnu || OS=freebsd
 
 // REQUIRES: rdar102364960
 
diff --git a/test/Interop/Cxx/stdlib/print-stdlib-types.swift b/test/Interop/Cxx/stdlib/print-stdlib-types.swift
new file mode 100644
index 0000000000000..3c67a557b4970
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/print-stdlib-types.swift
@@ -0,0 +1,87 @@
+// RUN: %target-run-simple-swift(-cxx-interoperability-mode=default -Xfrontend -disable-availability-checking -I %S/Inputs) | %FileCheck %s
+
+// REQUIRES: executable_test
+// XFAIL: OS=windows-msvc
+// FIXME: We can't import std::unique_ptr or std::shared_ptr properly on Windows (https://github.com/apple/swift/issues/70226)
+
+import StdStringAndVector
+import StdUniquePtr
+
+func printStdString(s: std.string) {
+    print(s)
+    let swiftString = String(s)
+    print(swiftString)
+}
+
+func printStdUniquePtrOfInt() {
+    let uint = makeInt()
+    print(uint.pointee)
+}
+
+func printStdUniquePtrOfString() {
+    let ustring = makeString()
+    print(ustring.pointee)
+}
+
+func printStdSharedPtrOfInt() {
+    let sint = makeIntShared()
+    print(sint.pointee)
+    print(sint)
+}
+
+func printStdSharedPtrOfString() {
+    let sstring = makeStringShared()
+    print(sstring.pointee)
+    print(sstring)
+}
+
+func printStdVectorOfInt() {
+    let vecOfInt = makeVecOfInt()
+    print(vecOfInt[0])
+    print(vecOfInt)
+}
+
+func printStdVectorOfString() {
+    let vecOfString = makeVecOfString()
+    print(vecOfString[0])
+    print(vecOfString)
+}
+
+func printStruct() {
+    let s = S()
+    print(s.getPrivVec())
+    print(s.getProtStr())
+    print(s.pubStr)
+    print(s.pubVec)
+    print(s)
+}
+
+printStdString(s: "Hello")
+// CHECK: basic_string<CChar, {{.*}}, {{.*}}>()
+// CHECK: Hello
+
+printStdUniquePtrOfInt()
+// CHECK: 42
+printStdUniquePtrOfString()
+// CHECK: basic_string<CChar, {{.*}}, {{.*}}>()
+
+printStdSharedPtrOfInt()
+// CHECK: 42
+// CHECK: shared_ptr<CInt>()
+printStdSharedPtrOfString()
+// CHECK: basic_string<CChar, {{.*}}, {{.*}}>()
+// CHECK: shared_ptr<{{.*}}.basic_string<CChar, {{.*}}, {{.*}}>>
+
+printStdVectorOfInt()
+// CHECK: 1
+// CHECK: vector<CInt, {{.*}}>()
+printStdVectorOfString()
+// CHECK: basic_string<CChar, {{.*}}, {{.*}}>()
+// CHECK: vector<{{.*}}.basic_string<CChar, {{.*}}, {{.*}}>, {{.*}}>()
+
+printStruct()
+// CHECK: vector<{{.*}}.basic_string<CChar, {{.*}}, {{.*}}>, {{.*}}>()
+// CHECK: basic_string<CChar, {{.*}}, {{.*}}>()
+// CHECK: basic_string<CChar, {{.*}}, {{.*}}>()
+// CHECK: vector<{{.*}}.basic_string<CChar, {{.*}}, {{.*}}>, {{.*}}>()
+// CHECK: S(pubStr: {{.*}}.basic_string<CChar, {{.*}}, {{.*}}>(), pubVec: {{.*}}.vector<{{.*}}.basic_string<CChar, {{.*}}, {{.*}}>, {{.*}}>())
diff --git a/test/Interop/Cxx/stdlib/std-span-interface.swift b/test/Interop/Cxx/stdlib/std-span-interface.swift
index b910668fcdb11..c2f4b2de098c6 100644
--- a/test/Interop/Cxx/stdlib/std-span-interface.swift
+++ b/test/Interop/Cxx/stdlib/std-span-interface.swift
@@ -2,10 +2,12 @@
 // RUN: %target-swift-ide-test -plugin-path %swift-plugin-dir -I %S/Inputs -enable-experimental-feature SafeInteropWrappers -print-module -module-to-print=StdSpan -source-filename=x -enable-experimental-cxx-interop -Xcc -std=c++20 -module-cache-path %t > %t/interface.swift
 // RUN: %FileCheck %s < %t/interface.swift
 
-// REQUIRES: swift_feature_SafeInteropWrappers
+// Make sure we trigger typechecking and SIL diagnostics
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -I %S/Inputs -enable-experimental-feature SafeInteropWrappers -enable-experimental-feature Lifetimes -cxx-interoperability-mode=default -strict-memory-safety -warnings-as-errors -verify -Xcc -std=c++20 %s
 
-// FIXME swift-ci linux tests do not support std::span
-// UNSUPPORTED: OS=linux-gnu
+// REQUIRES: swift_feature_SafeInteropWrappers
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: rdar161999174
 
 #if !BRIDGING_HEADER
 import StdSpan
@@ -13,7 +15,7 @@ import StdSpan
 import CxxStdlib
 
 // CHECK:     struct DependsOnSelf {
-// CHECK:       @lifetime(borrow self)
+// CHECK:       @_lifetime(borrow self)
 // CHECK-NEXT:  @_alwaysEmitIntoClient @_disfavoredOverload public borrowing func get() -> Span<CInt>
 // CHECK-NEXT:  borrowing func get() -> ConstSpanOfInt
 
@@ -23,51 +25,221 @@ import CxxStdlib
 // CHECK-NEXT: func funcWithSafeWrapper3(_ v: borrowing VecOfInt) -> ConstSpanOfInt
 // CHECK:      struct X {
 // CHECK-NEXT:   init()
-// CHECK-NEXT:   @_alwaysEmitIntoClient public mutating func methodWithSafeWrapper(_ s: Span<CInt>)
+// CHECK-NEXT:   /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:   @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT:   @_alwaysEmitIntoClient @_disfavoredOverload public mutating func methodWithSafeWrapper(_ s: Span<CInt>)
 // CHECK-NEXT:   mutating func methodWithSafeWrapper(_ s: ConstSpanOfInt)
 // CHECK-NEXT: }
 // CHECK: struct SpanWithoutTypeAlias {
 // CHECK-NEXT:   init()
-// CHECK-NEXT:   @lifetime(borrow self)
-// CHECK-NEXT:   @_alwaysEmitIntoClient @_disfavoredOverload public mutating func bar() -> Span<CInt>
 // CHECK-NEXT:   mutating func bar() -> std.{{.*}}span<__cxxConst<CInt>, _C{{.*}}_{{.*}}>
-// CHECK-NEXT:   @_alwaysEmitIntoClient public mutating func foo(_ s: Span<CInt>)
 // CHECK-NEXT:   mutating func foo(_ s: std.{{.*}}span<__cxxConst<CInt>, _C{{.*}}_{{.*}}>)
+// CHECK-NEXT:   mutating func otherTemplatedType(_ copy: ConstSpanOfInt, _: S<CInt>)
+// CHECK-NEXT:   mutating func otherTemplatedType2(_ copy: ConstSpanOfInt, _: UnsafeMutablePointer<S<CInt>>!)
 // CHECK-NEXT: }
 
-// CHECK: @lifetime(s: copy s)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func FuncWithMutableSafeWrapper(_ s: inout MutableSpan<CInt>)
-// CHECK-NEXT: @lifetime(copy s)
-// CHECK-NEXT: @lifetime(s: copy s)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func FuncWithMutableSafeWrapper2(_ s: inout MutableSpan<CInt>) -> MutableSpan<CInt>
-// CHECK-NEXT: @lifetime(borrow v)
+// CHECK:      /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(s: copy s)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func FuncWithMutableSafeWrapper(_ s: inout MutableSpan<CInt>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy s)
+// CHECK-NEXT: @_lifetime(s: copy s)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func FuncWithMutableSafeWrapper2(_ s: inout MutableSpan<CInt>) -> MutableSpan<CInt>
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(&v)
 // CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func FuncWithMutableSafeWrapper3(_ v: inout VecOfInt) -> MutableSpan<CInt>
-// CHECK-NEXT: @lifetime(copy p)
-// CHECK-NEXT: @lifetime(p: copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func MixedFuncWithMutableSafeWrapper1(_ p: inout MutableSpan<Int32>) -> MutableSpan<CInt>
-// CHECK-NEXT: @lifetime(borrow v)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func MixedFuncWithMutableSafeWrapper1(_ p: inout MutableSpan<Int32>) -> MutableSpan<CInt>
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(&v)
 // CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func MixedFuncWithMutableSafeWrapper2(_ v: inout VecOfInt, _ len: Int32) -> MutableSpan<Int32>
-// CHECK-NEXT: @lifetime(s: copy s)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func MixedFuncWithMutableSafeWrapper3(_ s: inout MutableSpan<CInt>, _ p: UnsafeMutableBufferPointer<Int32>)
-// CHECK-NEXT: @lifetime(s: copy s)
-// CHECK-NEXT: @lifetime(p: copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func MixedFuncWithMutableSafeWrapper4(_ s: inout MutableSpan<CInt>, _ p: inout MutableSpan<Int32>)
-// CHECK-NEXT: @lifetime(p: copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func MixedFuncWithMutableSafeWrapper5(_ s: SpanOfInt, _ p: inout MutableSpan<Int32>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func MixedFuncWithMutableSafeWrapper6(_ s: SpanOfInt, _ p: UnsafeMutableBufferPointer<Int32>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func MixedFuncWithMutableSafeWrapper7(_ p: UnsafeMutableBufferPointer<Int32>) -> SpanOfInt
-
-// CHECK: @_alwaysEmitIntoClient public func funcWithSafeWrapper(_ s: Span<CInt>)
-// CHECK-NEXT: @lifetime(copy s)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func funcWithSafeWrapper2(_ s: Span<CInt>) -> Span<CInt>
-// CHECK-NEXT: @lifetime(borrow v)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(s: copy s)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func MixedFuncWithMutableSafeWrapper3(_ s: inout MutableSpan<CInt>, _ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(s: copy s)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func MixedFuncWithMutableSafeWrapper4(_ s: inout MutableSpan<CInt>, _ p: inout MutableSpan<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(p: copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func MixedFuncWithMutableSafeWrapper5(_ s: SpanOfInt, _ p: inout MutableSpan<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func MixedFuncWithMutableSafeWrapper6(_ s: SpanOfInt, _ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func MixedFuncWithMutableSafeWrapper7(_ p: UnsafeMutableBufferPointer<Int32>) -> SpanOfInt
+
+// CHECK:      /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func `func`(_ copy: Span<CInt>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func funcWithSafeWrapper(_ s: Span<CInt>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy s)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func funcWithSafeWrapper2(_ s: Span<CInt>) -> Span<CInt>
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(borrow v)
 // CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func funcWithSafeWrapper3(_ v: borrowing VecOfInt) -> Span<CInt>
-// CHECK-NEXT: @lifetime(copy p)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func mixedFuncWithSafeWrapper1(_ p: Span<Int32>) -> Span<CInt>
-// CHECK-NEXT: @lifetime(borrow v)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy p)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func mixedFuncWithSafeWrapper1(_ p: Span<Int32>) -> Span<CInt>
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(borrow v)
 // CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func mixedFuncWithSafeWrapper2(_ v: borrowing VecOfInt, _ len: Int32) -> Span<Int32>
-// CHECK-NEXT: @_alwaysEmitIntoClient public func mixedFuncWithSafeWrapper3(_ s: Span<CInt>, _ p: UnsafeMutableBufferPointer<Int32>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func mixedFuncWithSafeWrapper4(_ s: Span<CInt>, _ p: Span<Int32>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func mixedFuncWithSafeWrapper5(_ s: ConstSpanOfInt, _ p: Span<Int32>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func mixedFuncWithSafeWrapper6(_ s: ConstSpanOfInt, _ p: UnsafeMutableBufferPointer<Int32>)
-// CHECK-NEXT: @_alwaysEmitIntoClient public func mixedFuncWithSafeWrapper7(_ p: UnsafeBufferPointer<Int32>) -> ConstSpanOfInt
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func mixedFuncWithSafeWrapper3(_ s: Span<CInt>, _ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func mixedFuncWithSafeWrapper4(_ s: Span<CInt>, _ p: Span<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func mixedFuncWithSafeWrapper5(_ s: ConstSpanOfInt, _ p: Span<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func mixedFuncWithSafeWrapper6(_ s: ConstSpanOfInt, _ p: UnsafeMutableBufferPointer<Int32>)
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func mixedFuncWithSafeWrapper7(_ p: UnsafeBufferPointer<Int32>) -> ConstSpanOfInt
+
+// CHECK-NEXT: /// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT: @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: @_lifetime(copy: copy copy)
+// CHECK-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func mutableKeyword(_ copy: inout MutableSpan<CInt>)
+
+func callMethodWithSafeWrapper(_ x: inout X, s: Span<CInt>) {
+    x.methodWithSafeWrapper(s)
+}
+
+func callFooBar(_ x: inout SpanWithoutTypeAlias, _ s: ConstSpanOfInt) {
+    let _: Span<CInt> = x.bar() // expected-error {{cannot convert value of type}}
+    unsafe x.foo(s)
+}
+
+@_lifetime(span: copy span)
+func callFuncWithMutableSafeWrapper(_ span: inout MutableSpan<CInt>, ) {
+    FuncWithMutableSafeWrapper(&span)
+}
+
+@_lifetime(span: copy span)
+func callFuncWithMutableSafeWrapper2(_ span: inout MutableSpan<CInt>, ) {
+    let _: MutableSpan<CInt> = FuncWithMutableSafeWrapper2(&span)
+}
+
+@_lifetime(span: copy span)
+func callMixedFuncWithMutableSafeWrapper1(_ span: inout MutableSpan<CInt>, ) {
+    let _: MutableSpan<CInt> = MixedFuncWithMutableSafeWrapper1(&span)
+}
+
+func MixedFuncWithMutableSafeWrapper2(_ v: VecOfInt) {
+    var v2 = v
+    let _ : MutableSpan<Int32> = MixedFuncWithMutableSafeWrapper2(&v2, 37)
+}
+
+@_lifetime(span: copy span)
+func callMixedFuncWithMutableSafeWrapper3(_ span: inout MutableSpan<CInt>, _ p: UnsafeMutableBufferPointer<CInt>) {
+    unsafe MixedFuncWithMutableSafeWrapper3(&span, p)
+}
+
+@_lifetime(span1: copy span2)
+@_lifetime(span2: copy span2)
+func callMixedFuncWithMutableSafeWrapper4(_ span1: inout MutableSpan<CInt>, _ span2: inout MutableSpan<CInt>) {
+    MixedFuncWithMutableSafeWrapper4(&span1, &span2)
+}
+
+@_lifetime(span: copy span)
+func callMixedFuncWithMutableSafeWrapper5(_ span: inout MutableSpan<CInt>, _ s: SpanOfInt) {
+    unsafe MixedFuncWithMutableSafeWrapper5(s, &span)
+}
+
+func callMixedFuncWithMutableSafeWrapper6(_ s: SpanOfInt, _ p: UnsafeMutableBufferPointer<CInt>) {
+    unsafe MixedFuncWithMutableSafeWrapper6(s, p)
+}
+
+func callMixedFuncWithMutableSafeWrapper7(_ p: UnsafeMutableBufferPointer<CInt>) {
+    let _ = unsafe MixedFuncWithMutableSafeWrapper7(p)
+}
+
+func callFuncWithSafeWrapper(_ s: Span<CInt>) {
+    funcWithSafeWrapper(s)
+}
+
+func callFuncWithSafeWrapper2(_ s: Span<CInt>) {
+    let _ = funcWithSafeWrapper2(s)
+}
+
+func callFuncWithSafeWrapper3(_ v: borrowing VecOfInt) {
+    let _: Span<CInt> = funcWithSafeWrapper3(v)
+}
+
+func callMixedFuncWithSafeWrapper1(_ s: Span<CInt>) {
+    let _: Span<CInt> = mixedFuncWithSafeWrapper1(s)
+}
+
+func callMixedFuncWithSafeWrapper2(_ v: borrowing VecOfInt) {
+    let _: Span<CInt> = mixedFuncWithSafeWrapper2(v, 73)
+}
+
+func callMixedFuncWithSafeWrapper3(_ s: Span<CInt>, _ p: UnsafeMutableBufferPointer<CInt>) {
+    unsafe mixedFuncWithSafeWrapper3(s, p)
+}
+
+func callMixedFuncWithSafeWrapper4(_ s: Span<CInt>, _ s2: Span<CInt>) {
+    mixedFuncWithSafeWrapper4(s, s2)
+}
+
+func callMixedFuncWithSafeWrapper5(_ s: ConstSpanOfInt, _ s2: Span<CInt>) {
+    unsafe mixedFuncWithSafeWrapper5(s, s2)
+}
+
+func callMixedFuncWithSafeWrapper6(_ s: ConstSpanOfInt, _ p: UnsafeMutableBufferPointer<CInt>) {
+    unsafe mixedFuncWithSafeWrapper6(s, p)
+}
+
+func callMixedFuncWithSafeWrapper7(_ p: UnsafeBufferPointer<CInt>) {
+    let _: ConstSpanOfInt = unsafe mixedFuncWithSafeWrapper7(p)
+}
+
+@_lifetime(span: copy span)
+func callMutableKeyword(_ span: inout MutableSpan<CInt>) {
+    mutableKeyword(&span)
+}
+
+func callSpanWithoutTypeAlias(_ span: Span<CInt>) {
+  spanWithoutTypeAlias(span) // expected-error {{cannot convert value of type}}
+}
+
+func callMutableSpanWithoutTypeAlias(_ span: consuming MutableSpan<CInt>) {
+  mutableSpanWithoutTypeAlias(&span) // expected-error {{cannot convert value of type}}
+}
diff --git a/test/Interop/Cxx/stdlib/std-span-transformed-execution.swift b/test/Interop/Cxx/stdlib/std-span-transformed-execution.swift
index a1ada02cb4dff..1b22a53f8e671 100644
--- a/test/Interop/Cxx/stdlib/std-span-transformed-execution.swift
+++ b/test/Interop/Cxx/stdlib/std-span-transformed-execution.swift
@@ -1,7 +1,6 @@
-// RUN: %target-run-simple-swift(-plugin-path %swift-plugin-dir -I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -swift-version 6 -Xfrontend -disable-availability-checking -Xcc -std=c++20 -enable-experimental-feature LifetimeDependence -enable-experimental-feature SafeInteropWrappers)
+// REQUIRES: rdar162106653
 
-// FIXME swift-ci linux tests do not support std::span
-// UNSUPPORTED: OS=linux-gnu
+// RUN: %target-run-simple-swift(-plugin-path %swift-plugin-dir -I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -swift-version 6 -Xfrontend -disable-availability-checking -Xcc -std=c++20 -enable-experimental-feature LifetimeDependence -enable-experimental-feature SafeInteropWrappers)
 
 // TODO: test failed in Windows PR testing: rdar://144384453
 // UNSUPPORTED: OS=windows-msvc
diff --git a/test/Interop/Cxx/stdlib/use-std-function.swift b/test/Interop/Cxx/stdlib/use-std-function.swift
index 72ebcead2876e..4509bc8031d33 100644
--- a/test/Interop/Cxx/stdlib/use-std-function.swift
+++ b/test/Interop/Cxx/stdlib/use-std-function.swift
@@ -7,17 +7,6 @@
 
 // REQUIRES: executable_test
 
-// libstdc++11 declares a templated constructor of std::function with an rvalue-reference parameter,
-// which aren't yet supported in Swift. Therefore initializing a std::function from Swift closures
-// will not work on the platforms that are shipped with this version of libstdc++ (rdar://125816354).
-// XFAIL: LinuxDistribution=ubuntu-24.04
-// XFAIL: LinuxDistribution=ubuntu-22.04
-// XFAIL: LinuxDistribution=rhel-9.3
-// XFAIL: LinuxDistribution=rhel-9.4
-// XFAIL: LinuxDistribution=rhel-9.5
-// XFAIL: LinuxDistribution=fedora-39
-// XFAIL: LinuxDistribution=debian-12
-
 import StdlibUnittest
 import StdFunction
 import CxxStdlib
@@ -66,12 +55,11 @@ StdFunctionTestSuite.test("FunctionStringToString init from closure and pass as
   expectEqual(std.string("prefixabcabc"), res)
 }
 
-// FIXME: assertion for address-only closure params (rdar://124501345)
-//StdFunctionTestSuite.test("FunctionStringToStringConstRef init from closure and pass as parameter") {
-//  let res = invokeFunctionTwiceConstRef(.init({ $0 + std.string("abc") }),
-//                                        std.string("prefix"))
-//  expectEqual(std.string("prefixabcabc"), res)
-//}
+StdFunctionTestSuite.test("FunctionStringToStringConstRef init from closure and pass as parameter") {
+  let res = invokeFunctionTwiceConstRef(.init({ $0 + std.string("abc") }),
+                                        std.string("prefix"))
+  expectEqual(std.string("prefixabcabc"), res)
+}
 #endif
 
 runAllTests()
diff --git a/test/Interop/Cxx/stdlib/use-std-map-typechecker.swift b/test/Interop/Cxx/stdlib/use-std-map-typechecker.swift
new file mode 100644
index 0000000000000..1ae4e73676583
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/use-std-map-typechecker.swift
@@ -0,0 +1,16 @@
+// RUN: not %target-swift-frontend %s -typecheck -I %S/Inputs -cxx-interoperability-mode=default -diagnostic-style llvm 2>&1 | %FileCheck %s
+
+import StdMap
+import CxxStdlib
+
+func takeCopyable<T: Copyable>(_ x: T) {} 
+
+let mapNonCopyableKey = MapNonCopyableKey() 
+takeCopyable(mapNonCopyableKey) 
+// CHECK: error: global function 'takeCopyable' requires that 'MapNonCopyableKey' {{.*}} conform to 'Copyable'
+// CHECK: note: 'where T: Copyable' is implicit here
+
+let mapNonCopyableValue = MapNonCopyableValue() 
+takeCopyable(mapNonCopyableValue) 
+// CHECK: error: global function 'takeCopyable' requires that 'MapNonCopyableValue' {{.*}} conform to 'Copyable'
+// CHECK: note: 'where T: Copyable' is implicit here
diff --git a/test/Interop/Cxx/stdlib/use-std-map.swift b/test/Interop/Cxx/stdlib/use-std-map.swift
index 3ab8a84690fec..9c7b8efbdb8de 100644
--- a/test/Interop/Cxx/stdlib/use-std-map.swift
+++ b/test/Interop/Cxx/stdlib/use-std-map.swift
@@ -11,7 +11,11 @@
 
 // REQUIRES: executable_test
 //
-// REQUIRES: OS=macosx || OS=linux-gnu
+// REQUIRES: OS=macosx || OS=linux-gnu || OS=freebsd
+
+// Undefined hidden symbol to C++ voidify in libcxx
+// rdar://121551667
+// XFAIL: OS=freebsd
 
 import StdlibUnittest
 #if !BRIDGING_HEADER
@@ -132,6 +136,39 @@ StdMapTestSuite.test("UnorderedMap.init(grouping:by:)") {
   expectEqual(m[3]?.size(), 6)
 }
 
+StdMapTestSuite.test("Dictionary<CInt, CInt>.init(_: Map)") {
+  let cxxMap0 = Map()
+  let swiftMap0 = Dictionary<CInt, CInt>(cxxMap0)
+  expectTrue(swiftMap0.isEmpty)
+
+  let cxxMap1 = initMap()
+  let swiftMap1 = Dictionary<CInt, CInt>(cxxMap1)
+  expectEqual(swiftMap1, [1 : 3, 2 : 2, 3 : 3])
+}
+
+StdMapTestSuite.test("Dictionary<CInt, CInt>.init(_: UnorderedMap)") {
+  let cxxMap0 = UnorderedMap()
+  let swiftMap0 = Dictionary<CInt, CInt>(cxxMap0)
+  expectTrue(swiftMap0.isEmpty)
+
+  let cxxMap1 = initUnorderedMap()
+  let swiftMap1 = Dictionary<CInt, CInt>(cxxMap1)
+  expectEqual(swiftMap1, [1 : 3, 2 : 2, 3 : 3])
+}
+
+StdMapTestSuite.test("Dictionary<std.string, std.string>.init(_: MapStrings)") {
+  let cxxMap0 = MapStrings()
+  let swiftMap0 = Dictionary<std.string, std.string>(cxxMap0)
+  expectTrue(swiftMap0.isEmpty)
+
+  var cxxMap1 = MapStrings()
+  cxxMap1[std.string("abc")] = std.string("def")
+  cxxMap1[std.string("890")] = std.string("3210")
+  let swiftMap1 = Dictionary<std.string, std.string>(cxxMap1)
+  expectEqual(swiftMap1, [std.string("abc") : std.string("def"),
+                          std.string("890") : std.string("3210")])
+}
+
 StdMapTestSuite.test("Map.subscript") {
   // This relies on the `std::map` conformance to `CxxDictionary` protocol.
   var m = initMap()
@@ -427,6 +464,103 @@ StdMapTestSuite.test("UnorderedMap.merge(map)") {
   expectEqual(m[3], 3)
 }
 
+StdMapTestSuite.test("Map.merge(CxxDictionary)") {
+  // Empty map merging with empty map.
+  var emptyMap = initEmptyMap()
+  emptyMap.merge(initEmptyUnorderedMap()) { v0, _ in v0 }
+  expectTrue(emptyMap.empty())
+
+  emptyMap.merge(initEmptyUnorderedMap()) { _, v1 in v1 }
+  expectTrue(emptyMap.empty())
+
+  // Empty map merging with non-empty map.
+  emptyMap.merge(initUnorderedMap()) { v0, _ in v0 }
+  expectEqual(emptyMap[1], 3)
+  expectEqual(emptyMap[2], 2)
+  expectEqual(emptyMap[3], 3)
+
+  emptyMap = initEmptyMap()
+  emptyMap.merge(initUnorderedMap()) { _, v1 in v1 }
+  expectEqual(emptyMap[1], 3)
+  expectEqual(emptyMap[2], 2)
+  expectEqual(emptyMap[3], 3)
+
+  // Non-empty map merging with empty map.
+  var map = initMap()
+  map.merge(initUnorderedMap()) { v0, _ in v0 }
+  expectEqual(emptyMap[1], 3)
+  expectEqual(emptyMap[2], 2)
+  expectEqual(emptyMap[3], 3)
+
+  map.merge(initEmptyUnorderedMap()) { _, v1 in v1 }
+  expectEqual(map[1], 3)
+  expectEqual(map[2], 2)
+  expectEqual(map[3], 3)
+
+  // Non-empty map merging with non-empty map.
+  let noneEmptydMap = UnorderedMap([1: 4, 2: 5, 3: 6, 4: 7])
+  map.merge(noneEmptydMap) { v0, _ in v0 }
+  expectEqual(map[1], 3)
+  expectEqual(map[2], 2)
+  expectEqual(map[3], 3)
+  expectEqual(map[4], 7)
+
+  map.merge(noneEmptydMap) { _, v1 in v1 }
+  expectEqual(map[1], 4)
+  expectEqual(map[2], 5)
+  expectEqual(map[3], 6)
+  expectEqual(map[4], 7)
+}
+
+StdMapTestSuite.test("UnorderedMap.merge(CxxDictionary)") {
+  // Empty map merging with empty map.
+  var emptyMap = initEmptyUnorderedMap()
+  emptyMap.merge(initEmptyMap()) { v0, _ in v0 }
+  expectTrue(emptyMap.empty())
+
+  emptyMap.merge(initEmptyMap()) { _, v1 in v1 }
+  expectTrue(emptyMap.empty())
+
+  // Empty map merging with non-empty map.
+  emptyMap.merge(initMap()) { v0, _ in v0 }
+  expectEqual(emptyMap[1], 3)
+  expectEqual(emptyMap[2], 2)
+  expectEqual(emptyMap[3], 3)
+
+  emptyMap = initEmptyUnorderedMap()
+  emptyMap.merge(initMap()) { _, v1 in v1 }
+  expectEqual(emptyMap[1], 3)
+  expectEqual(emptyMap[2], 2)
+  expectEqual(emptyMap[3], 3)
+
+  // Non-empty map merging with empty map.
+  var map = initUnorderedMap()
+  map.merge(initEmptyMap()) { _, v1 in v1 }
+  expectEqual(map[1], 3)
+  expectEqual(map[2], 2)
+  expectEqual(map[3], 3)
+
+  map.merge(initEmptyMap()) { v0, _ in v0 }
+  expectEqual(map[1], 3)
+  expectEqual(map[2], 2)
+  expectEqual(map[3], 3)
+
+  // Non-empty map merging with non-empty map.
+  let noneEmptyMap = Map([1: 4, 2: 5, 3: 6, 4: 7])
+
+  map.merge(noneEmptyMap) { v0, _ in v0 }
+  expectEqual(map[1], 3)
+  expectEqual(map[2], 2)
+  expectEqual(map[3], 3)
+  expectEqual(map[4], 7)
+
+  map.merge(noneEmptyMap) { _, v1 in v1 }
+  expectEqual(map[1], 4)
+  expectEqual(map[2], 5)
+  expectEqual(map[3], 6)
+  expectEqual(map[4], 7)
+}
+
 // `merging` is implemented by calling `merge`, so we can skip this test
 
 runAllTests()
diff --git a/test/Interop/Cxx/stdlib/use-std-optional-typechecker.swift b/test/Interop/Cxx/stdlib/use-std-optional-typechecker.swift
new file mode 100644
index 0000000000000..70b1f3b98670e
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/use-std-optional-typechecker.swift
@@ -0,0 +1,11 @@
+// RUN: not %target-swift-frontend %s -typecheck -I %S/Inputs -cxx-interoperability-mode=default -diagnostic-style llvm 2>&1 | %FileCheck %s
+
+import StdOptional
+import CxxStdlib
+
+func takeCopyable<T: Copyable>(_ x: T) {} 
+
+let nonNilOptNonCopyable = getNonNilOptionalHasDeletedCopyCtor()
+takeCopyable(nonNilOptNonCopyable)
+// CHECK: error: global function 'takeCopyable' requires that 'StdOptionalHasDeletedCopyCtor' {{.*}} conform to 'Copyable'
+// CHECK: note: 'where T: Copyable' is implicit here
diff --git a/test/Interop/Cxx/stdlib/use-std-optional.swift b/test/Interop/Cxx/stdlib/use-std-optional.swift
index fa7695854406d..7f75ae5bf302f 100644
--- a/test/Interop/Cxx/stdlib/use-std-optional.swift
+++ b/test/Interop/Cxx/stdlib/use-std-optional.swift
@@ -1,9 +1,15 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=swift-5.9)
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=swift-6)
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=upcoming-swift)
+// RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=upcoming-swift -enable-experimental-feature AddressableParameters)
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=upcoming-swift -Xcc -std=c++20)
 //
 // REQUIRES: executable_test
+// REQUIRES: swift_feature_AddressableParameters
+
+// Undefined hidden symbol to C++ voidify in libcxx
+// rdar://121551667
+// XFAIL: OS=freebsd
 
 import StdlibUnittest
 import StdOptional
@@ -16,11 +22,14 @@ StdOptionalTestSuite.test("pointee") {
   let pointee = nonNilOpt.pointee
   expectEqual(123, pointee)
 
-#if !os(Linux) // crashes on Ubuntu 18.04 (rdar://113414160)
+#if !os(Linux) && !os(FreeBSD) // crashes on Ubuntu 18.04 (rdar://113414160)
   var modifiedOpt = getNilOptional()
   modifiedOpt.pointee = 777
   expectEqual(777, modifiedOpt.pointee)
 #endif
+
+  let nonNilOptNonCopyable = getNonNilOptionalHasDeletedCopyCtor()
+  expectEqual(654, nonNilOptNonCopyable.pointee.value)
 }
 
 StdOptionalTestSuite.test("std::optional => Swift.Optional") {
@@ -52,4 +61,33 @@ StdOptionalTestSuite.test("std::optional as ExpressibleByNilLiteral") {
   expectFalse(res2)
 }
 
+StdOptionalTestSuite.test("std::optional init(_:Wrapped)") {
+  let optInt = StdOptionalInt(123)
+  expectEqual(123, optInt.pointee)
+
+  // FIXME: making these variables immutable triggers a miscompile on Linux
+  // (https://github.com/swiftlang/swift/issues/82765)
+  var optBoolTMutable = StdOptionalBool(true)
+  var optBoolFMutable = StdOptionalBool(false)
+  expectTrue(optBoolTMutable.pointee)
+  expectFalse(optBoolFMutable.pointee)
+
+  // If AddressableParameters are enabled, this issue does not happen.
+#if hasFeature(AddressableParameters)
+  let optBoolT = StdOptionalBool(true)
+  let optBoolF = StdOptionalBool(false)
+  expectTrue(optBoolT.pointee)
+  expectFalse(optBoolF.pointee)
+#endif
+
+  let optString = StdOptionalString(std.string("abc"))
+  expectEqual(std.string("abc"), optString.pointee)
+
+  let optOptInt = StdOptionalOptionalInt(StdOptionalInt(456))
+  expectEqual(456, optOptInt.pointee.pointee)
+
+  let optConstexprCtor = StdOptionalHasConstexprCtor(HasConstexprCtor(321))
+  expectEqual(321, optConstexprCtor.pointee.value)
+}
+
 runAllTests()
diff --git a/test/Interop/Cxx/stdlib/use-std-set-typechecker.swift b/test/Interop/Cxx/stdlib/use-std-set-typechecker.swift
new file mode 100644
index 0000000000000..e71a3e60717b4
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/use-std-set-typechecker.swift
@@ -0,0 +1,11 @@
+// RUN: not %target-swift-frontend %s -typecheck -I %S/Inputs -cxx-interoperability-mode=default -diagnostic-style llvm 2>&1 | %FileCheck %s
+
+import StdSet
+import CxxStdlib
+
+func takeCopyable<T: Copyable>(_ x: T) {} 
+
+let setNonCopyable = SetOfNonCopyable() 
+takeCopyable(setNonCopyable) 
+// CHECK: error: global function 'takeCopyable' requires that 'SetOfNonCopyable' {{.*}} conform to 'Copyable'
+// CHECK: note: 'where T: Copyable' is implicit here
diff --git a/test/Interop/Cxx/stdlib/use-std-set.swift b/test/Interop/Cxx/stdlib/use-std-set.swift
index 6077f32465047..af873659a33fc 100644
--- a/test/Interop/Cxx/stdlib/use-std-set.swift
+++ b/test/Interop/Cxx/stdlib/use-std-set.swift
@@ -16,6 +16,7 @@
 //
 // Enable this everywhere once we have a solution for modularizing other C++ stdlibs: rdar://87654514
 // REQUIRES: OS=macosx || OS=linux-gnu
+// UNSUPPORTED: LinuxDistribution=fedora-41
 
 import StdlibUnittest
 #if !BRIDGING_HEADER
diff --git a/test/Interop/Cxx/stdlib/use-std-span-typechecker.swift b/test/Interop/Cxx/stdlib/use-std-span-typechecker.swift
index c367c3e200dda..ba5d494ad0955 100644
--- a/test/Interop/Cxx/stdlib/use-std-span-typechecker.swift
+++ b/test/Interop/Cxx/stdlib/use-std-span-typechecker.swift
@@ -1,7 +1,6 @@
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -enable-experimental-cxx-interop -Xcc -std=c++20 2>&1
+// REQUIRES: rdar162106722
 
-// FIXME swift-ci linux tests do not support std::span
-// UNSUPPORTED: OS=linux-gnu
+// RUN: %target-typecheck-verify-swift -I %S/Inputs -enable-experimental-cxx-interop -Xcc -std=c++20 2>&1
 
 import StdSpan
 
@@ -11,3 +10,9 @@ arr.withUnsafeBufferPointer { ubpointer in
     let _ = ConstSpanOfInt(ubpointer.baseAddress!, ubpointer.count) 
     // expected-warning@-1 {{'init(_:_:)' is deprecated: use 'init(_:)' instead.}}
 }
+
+arr.withUnsafeBufferPointer { ubpointer in 
+    // FIXME: this crashes the compiler once we import span's templated ctors as Swift generics.
+    let _ = ConstSpanOfInt(ubpointer.baseAddress, ubpointer.count)
+    // expected-warning@-1 {{'init(_:_:)' is deprecated: use 'init(_:)' instead.}}
+}
diff --git a/test/Interop/Cxx/stdlib/use-std-span.swift b/test/Interop/Cxx/stdlib/use-std-span.swift
index 59bb3ff60a05b..37a817c027cfa 100644
--- a/test/Interop/Cxx/stdlib/use-std-span.swift
+++ b/test/Interop/Cxx/stdlib/use-std-span.swift
@@ -1,9 +1,8 @@
+// REQUIRES: rdar162106580
+
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -Xcc -std=c++20)
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -Xcc -std=c++20 -Xcc -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG)
 
-// FIXME swift-ci linux tests do not support std::span
-// UNSUPPORTED: OS=linux-gnu
-
 // TODO: test failed in Windows PR testing: rdar://144384453
 // UNSUPPORTED: OS=windows-msvc
 
@@ -687,6 +686,30 @@ StdSpanTestSuite.test("Convert between Swift and C++ span types")
       expectEqual(cxxSpan[2], 3)
     }
   }
+  do {
+    var arr: [Int32] = [1, 2, 3]
+    arr.withUnsafeMutableBufferPointer{ ubpointer in
+      let s = SpanOfInt(ubpointer.baseAddress!, ubpointer.count)
+      let swiftSpan = MutableSpan(_unsafeCxxSpan: s)
+      expectEqual(swiftSpan.count, 3)
+      expectFalse(swiftSpan.isEmpty)
+      expectEqual(swiftSpan[0], 1)
+      expectEqual(swiftSpan[1], 2)
+      expectEqual(swiftSpan[2], 3)
+    }
+  }
+  do {
+    var arr: [Int32] = [1, 2, 3]
+    arr.withUnsafeMutableBufferPointer{ ubpointer in
+      let s = MutableSpan(_unsafeElements: ubpointer)
+      let cxxSpan = SpanOfInt(s)
+      expectEqual(cxxSpan.size(), 3)
+      expectFalse(cxxSpan.empty())
+      expectEqual(cxxSpan[0], 1)
+      expectEqual(cxxSpan[1], 2)
+      expectEqual(cxxSpan[2], 3)
+    }
+  }
 }
 
 runAllTests()
diff --git a/test/Interop/Cxx/stdlib/use-std-string-optional-error.swift b/test/Interop/Cxx/stdlib/use-std-string-optional-error.swift
new file mode 100644
index 0000000000000..aec7d60377218
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/use-std-string-optional-error.swift
@@ -0,0 +1,8 @@
+// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=default
+import CxxStdlib
+
+let tmpOpt: String? = "üüüüüüü"
+let cppString1 = std.string(tmpOpt) // expected-warning {{'init(_:)' is deprecated: unwrap the optional value and use init(_ string: UnsafePointer<CChar>) instead}}
+
+let tmpNonOpt: String = "üüüüüüü"
+let cppString2 = std.string(tmpNonOpt)
diff --git a/test/Interop/Cxx/stdlib/use-std-string.swift b/test/Interop/Cxx/stdlib/use-std-string.swift
index 8f519a3fbe451..e1b23d3adfb2f 100644
--- a/test/Interop/Cxx/stdlib/use-std-string.swift
+++ b/test/Interop/Cxx/stdlib/use-std-string.swift
@@ -73,6 +73,23 @@ StdStringTestSuite.test("std::string <=> Swift.String") {
     expectEqual(swift8, "Hello, World!")
 }
 
+StdStringTestSuite.test("std::string <=> Optional<String>") {
+    let ascii: String? = "aaaaaaa"
+    let nonAscii: String? = "üüüüüüü"
+    let nilString: String? = nil
+    let emptyString: String? = ""
+
+    let s1 = std.string(ascii!)
+    let s2 = std.string(nonAscii!)
+    let s3 = std.string(nilString ?? "")
+    let s4 = std.string(emptyString!)
+
+    expectEqual(String(s1), "aaaaaaa")
+    expectEqual(String(s2), "üüüüüüü")
+    expectEqual(String(s3), "")
+    expectEqual(String(s4), "")
+}
+
 StdStringTestSuite.test("std::string operators") {
     var s1 = std.string("something")
     let s2 = std.string("123")
@@ -133,6 +150,26 @@ StdStringTestSuite.test("std::u32string operators") {
     expectTrue(s1 == "something123literal")
 }
 
+StdStringTestSuite.test("std::wstring operators") {
+    var s1 = std.wstring("something")
+    let s2 = std.wstring("123")
+    let sum = s1 + s2
+    expectEqual(sum, std.wstring("something123"))
+
+    expectFalse(s1 == s2)
+    let s3 = std.wstring("something123")
+    expectFalse(s1 == s3)
+    expectFalse(s2 == s3)
+
+    s1 += s2
+    expectTrue(s1 == std.wstring("something123"))
+    expectTrue(s1 == s3)
+
+    // Make sure the operators work together with ExpressibleByStringLiteral conformance.
+    s1 += "literal"
+    expectTrue(s1 == "something123literal")
+}
+
 StdStringTestSuite.test("std::string::append") {
     var s1 = std.string("0123")
     let s2 = std.string("abc")
@@ -154,6 +191,13 @@ StdStringTestSuite.test("std::u32string::append") {
     expectEqual(s1, std.u32string("0123abc"))
 }
 
+StdStringTestSuite.test("std::wstring::append") {
+    var s1 = std.wstring("0123")
+    let s2 = std.wstring("abc")
+    s1.append(s2)
+    expectEqual(s1, std.wstring("0123abc"))
+}
+
 StdStringTestSuite.test("std::string comparison") {
     let s1 = std.string("abc")
     let s2 = std.string("def")
@@ -202,6 +246,22 @@ StdStringTestSuite.test("std::u32string comparison") {
     expectTrue(s1 == s3)
 }
 
+StdStringTestSuite.test("std::wstring comparison") {
+    let s1 = std.wstring("abc")
+    let s2 = std.wstring("def")
+    let s3 = std.wstring("abc")
+
+    expectTrue(s1 < s2)
+    expectFalse(s2 < s1)
+    expectTrue(s1 <= s2)
+    expectFalse(s2 <= s1)
+    expectTrue(s2 > s1)
+    expectFalse(s1 > s2)
+    expectTrue(s2 >= s1)
+    expectFalse(s1 >= s2)
+    expectTrue(s1 == s3)
+}
+
 StdStringTestSuite.test("std::string as Hashable") {
     let s0 = std.string()
     let h0 = s0.hashValue
@@ -265,6 +325,27 @@ StdStringTestSuite.test("std::u32string as Hashable") {
     expectNotEqual(h2, h3)
 }
 
+StdStringTestSuite.test("std::wstring as Hashable") {
+    let s0 = std.wstring()
+    let h0 = s0.hashValue
+
+    let s1 = std.wstring("something")
+    let h1 = s1.hashValue
+
+    let s2 = std.wstring("something123")
+    let h2 = s2.hashValue
+
+    let s3 = std.wstring("something")
+    let h3 = s3.hashValue
+
+    expectEqual(h1, h3)
+    expectNotEqual(h0, h1)
+    expectNotEqual(h0, h2)
+    expectNotEqual(h0, h3)
+    expectNotEqual(h1, h2)
+    expectNotEqual(h2, h3)
+}
+
 StdStringTestSuite.test("std::u16string <=> Swift.String") {
     let cxx1 = std.u16string()
     let swift1 = String(cxx1)
@@ -384,6 +465,14 @@ StdStringTestSuite.test("std::u32string as Swift.CustomDebugStringConvertible")
     expectEqual(cxx3.debugDescription, "std.u32string(a�c)")
 }
 
+StdStringTestSuite.test("std::wstring as Swift.CustomDebugStringConvertible") {
+    let cxx1 = std.wstring()
+    expectEqual(cxx1.debugDescription, "std.wstring()")
+
+    let cxx2 = std.wstring("something123")
+    expectEqual(cxx2.debugDescription, "std.wstring(something123)")
+}
+
 StdStringTestSuite.test("std::string as Swift.Sequence") {
     let cxx1 = std.string()
     var iterated = false
@@ -459,6 +548,14 @@ StdStringTestSuite.test("std::u32string as Swift.CustomStringConvertible") {
     expectEqual(cxx4.description, "Hello, 世界")
 }
 
+StdStringTestSuite.test("std::wstring as Swift.CustomStringConvertible") {
+    let cxx1 = std.wstring()
+    expectEqual(cxx1.description, "")
+
+    let cxx2 = std.wstring("something123")
+    expectEqual(cxx2.description, "something123")
+}
+
 StdStringTestSuite.test("std::string from C string") {
     let str = "abc".withCString { ptr in
         std.string(ptr)
@@ -490,4 +587,47 @@ StdStringTestSuite.test("pass as a default argument") {
 }
 #endif
 
+StdStringTestSuite.test("std.string to span").require(.stdlib_6_2).code {
+    guard #available(SwiftStdlib 6.2, *) else { return }
+
+    let s = std.string("abc")
+    // FIXME: remove once borrow checking is fixed.
+    withExtendedLifetime(s) {
+        let span = s.span
+        expectEqual(span.count, 3)
+        expectFalse(span.isEmpty)
+        expectEqual(span[0], 97)
+        expectEqual(span[1], 98)
+        expectEqual(span[2], 99)
+
+        let utfspan = s.utf8Span!
+        let str = String(copying: utfspan)
+        expectEqual(str, "abc")
+    }
+
+    let scalars: [UInt16] = [97, 55296, 99]
+    var s_16 = std.u16string()
+    for scalar: UInt16 in scalars {
+        s_16.push_back(scalar)
+    }
+    // FIXME: remove once borrow checking is fixed.
+    withExtendedLifetime(s_16) {
+        let span_16 = s_16.span
+        expectEqual(span_16.count, 3)
+        expectFalse(span_16.isEmpty)
+        for (n, c) in scalars.enumerated() {
+            expectEqual(span_16[n], c)
+        }
+    }
+
+    let s_32 = std.u32string("abc")
+    // FIXME: remove once borrow checking is fixed.
+    withExtendedLifetime(s_32) {
+        let span_32 = s_32.span
+        for (n, c) in "abc".enumerated() {
+            expectEqual(span_32[n], UInt32(c.asciiValue!))
+        }
+    }
+}
+
 runAllTests()
diff --git a/test/Interop/Cxx/stdlib/use-std-unique-ptr-typechecker.swift b/test/Interop/Cxx/stdlib/use-std-unique-ptr-typechecker.swift
new file mode 100644
index 0000000000000..636ba05653689
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/use-std-unique-ptr-typechecker.swift
@@ -0,0 +1,12 @@
+// RUN: not %target-swift-frontend %s -typecheck -I %S/Inputs -cxx-interoperability-mode=default -diagnostic-style llvm 2>&1 | %FileCheck %s
+
+// UNSUPPORTED: OS=windows-msvc
+
+import StdUniquePtr
+import CxxStdlib
+
+func takeCopyable<T: Copyable>(_ x: T) {} 
+
+let vecUniquePtr = getVectorNonCopyableUniquePtr()
+takeCopyable(vecUniquePtr)
+// CHECK: error: global function 'takeCopyable' requires that 'std{{.*}}vector{{.*}}unique_ptr{{.*}}NonCopyable{{.*}}' conform to 'Copyable'
diff --git a/test/Interop/Cxx/stdlib/use-std-vector-typechecker.swift b/test/Interop/Cxx/stdlib/use-std-vector-typechecker.swift
new file mode 100644
index 0000000000000..908ef4f60af66
--- /dev/null
+++ b/test/Interop/Cxx/stdlib/use-std-vector-typechecker.swift
@@ -0,0 +1,22 @@
+// RUN: not %target-swift-frontend %s -typecheck -I %S/Inputs -cxx-interoperability-mode=default -diagnostic-style llvm 2>&1 | %FileCheck %s
+// XFAIL: OS=linux-androideabi
+
+import StdVector
+import CxxStdlib
+
+func takeCopyable<T: Copyable>(_ x: T) {} 
+func takeCxxVector<V: CxxVector>(_ v: V) {} 
+
+let vecNC = VectorOfNonCopyable()
+takeCopyable(vecNC)
+// CHECK: error: global function 'takeCopyable' requires that 'VectorOfNonCopyable' {{.*}} conform to 'Copyable'
+// CHECK: note: 'where T: Copyable' is implicit here
+
+takeCxxVector(vecNC) 
+// CHECK: error: global function 'takeCxxVector' requires that 'VectorOfNonCopyable' {{.*}} conform to 'CxxVector'
+// CHECK: note: where 'V' = 'VectorOfNonCopyable' {{.*}}
+
+let vecPointer = VectorOfPointer()
+takeCopyable(vecPointer)
+takeCxxVector(vecPointer)
+// CHECK-NOT: error
diff --git a/test/Interop/Cxx/stdlib/use-std-vector.swift b/test/Interop/Cxx/stdlib/use-std-vector.swift
index a4bde2c99aaf0..5e2a1f0d9c6dc 100644
--- a/test/Interop/Cxx/stdlib/use-std-vector.swift
+++ b/test/Interop/Cxx/stdlib/use-std-vector.swift
@@ -194,15 +194,21 @@ StdVectorTestSuite.test("VectorOfInt to span").require(.stdlib_6_2).code {
   guard #available(SwiftStdlib 6.2, *) else { return }
 
   let v = Vector([1, 2, 3])
-  // FIXME: remove 'withExtendedLifetime' once lifetime analysis is fixed.
-  withExtendedLifetime(v) {
-    let s = $0.span
-    expectEqual(s.count, 3)
-    expectFalse(s.isEmpty)
-    expectEqual(s[0], 1)
-    expectEqual(s[1], 2)
-    expectEqual(s[2], 3)
-  }
+  let s = v.span
+  expectEqual(s.count, 3)
+  expectFalse(s.isEmpty)
+  expectEqual(s[0], 1)
+  expectEqual(s[1], 2)
+  expectEqual(s[2], 3)
+}
+
+StdVectorTestSuite.test("VectorOfImmortalRefPtr").require(.stdlib_5_8).code {
+    guard #available(SwiftStdlib 5.8, *) else { return }
+
+    var v = VectorOfImmortalRefPtr()
+    let i = ImmortalRef.create(123)
+    v.push_back(i)
+    expectEqual(v[0]?.value, 123)
 }
 
 runAllTests()
diff --git a/test/Interop/Cxx/stdlib/use-swift-concurrency.swift b/test/Interop/Cxx/stdlib/use-swift-concurrency.swift
index 35c739342b319..711ff39b2debb 100644
--- a/test/Interop/Cxx/stdlib/use-swift-concurrency.swift
+++ b/test/Interop/Cxx/stdlib/use-swift-concurrency.swift
@@ -4,6 +4,7 @@
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
 // REQUIRES: concurrency_runtime
+// UNSUPPORTED: back_deployment_runtime || use_os_stdlib
 
 import StdlibUnittest
 
diff --git a/test/Interop/Cxx/swiftify-import/bounds-attrs-in-template.swift b/test/Interop/Cxx/swiftify-import/bounds-attrs-in-template.swift
new file mode 100644
index 0000000000000..c9cfaaa117d25
--- /dev/null
+++ b/test/Interop/Cxx/swiftify-import/bounds-attrs-in-template.swift
@@ -0,0 +1,68 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -I %t/Inputs -cxx-interoperability-mode=default -enable-experimental-feature SafeInteropWrappers %t/template.swift -dump-macro-expansions -emit-ir -o %t/out -verify -verify-ignore-unrelated
+// RUN: %target-swift-ide-test -plugin-path %swift-plugin-dir -I %t/Inputs -cxx-interoperability-mode=default -enable-experimental-feature SafeInteropWrappers -print-module -module-to-print=Template -source-filename=x | %FileCheck %s
+
+// CHECK: func cb_template<T>(_ p: UnsafePointer<T>!, _ size: Int{{.*}}) -> UnsafePointer<T>
+// CHECK: func eb_template<T>(_ p: UnsafePointer<T>!, _ end: UnsafePointer<T>!) -> UnsafePointer<T>
+// CHECK: func s_template<T>(_ p: UnsafePointer<T>!) -> UnsafePointer<T>
+// CHECK: func ui_template<T>(_ p: UnsafePointer<T>!) -> UnsafePointer<T>
+
+//--- Inputs/module.modulemap
+module Template {
+    header "template.h"
+    requires cplusplus
+}
+
+//--- Inputs/template.h
+#include <ptrcheck.h>
+#include <lifetimebound.h>
+
+template <class T>
+inline const T* __counted_by(size) cb_template(const T* __counted_by(size) p __noescape, int size) { return p; }
+
+template <class T>
+inline const T* __ended_by(end) eb_template(const T* __ended_by(end) p __noescape, const T* end) { return p; }
+
+template <class T>
+inline const T* __single s_template(const T* __single p) { return p; }
+
+template <class T>
+inline const T* __unsafe_indexable ui_template(const T* __unsafe_indexable p) { return p; }
+
+// FIXME: parse null_terminated in templated contexts
+// template <class T>
+// inline const T* __null_terminated nt_template(const T* __null_terminated p) {}
+
+//--- template.swift
+import Template
+
+// make sure the original functions are still available when parsing bounds attributes
+func testOriginalCB(p: UnsafePointer<CInt>, len: CInt) {
+  let _ = cb_template(p, len)
+}
+func testOriginalEB(p: UnsafePointer<CInt>, end: UnsafePointer<CInt>) {
+  let _ = eb_template(p, end)
+}
+func testOriginalS(s: UnsafePointer<CInt>) {
+  let _ = s_template(s)
+}
+func testOriginalUI(s: UnsafePointer<CInt>) {
+  let _ = ui_template(s)
+}
+
+ // FIXME: generate safe overloads for templated functions (rdar://151481042)
+func testSafeOverloadCB(s: Span<CInt>) {
+  // expected-error@+3{{generic parameter 'T' could not be inferred}}
+  // expected-error@+2{{cannot convert value of type 'Span<CInt>'}}
+  // expected-error@+1{{missing argument for parameter #2 in call}}
+  cb_template(s)
+}
+func testSafeOverloadEB(s: Span<CInt>) {
+  // expected-error@+3{{generic parameter 'T' could not be inferred}}
+  // expected-error@+2{{cannot convert value of type 'Span<CInt>'}}
+  // expected-error@+1{{missing argument for parameter #2 in call}}
+  eb_template(s)
+}
diff --git a/test/Interop/Cxx/swiftify-import/counted-by-in-namespace.swift b/test/Interop/Cxx/swiftify-import/counted-by-in-namespace.swift
index 38b3425136b1a..772dfc929b214 100644
--- a/test/Interop/Cxx/swiftify-import/counted-by-in-namespace.swift
+++ b/test/Interop/Cxx/swiftify-import/counted-by-in-namespace.swift
@@ -1,28 +1,66 @@
 // REQUIRES: swift_feature_SafeInteropWrappers
 
-// RUN: rm -rf %t
+// RUN: %empty-directory(%t)
 // RUN: split-file %s %t
-// RUN: %target-swift-ide-test -plugin-path %swift-plugin-dir -I %t/Inputs -cxx-interoperability-mode=upcoming-swift -enable-experimental-feature SafeInteropWrappers -print-module -module-to-print=Namespace -source-filename=x | %FileCheck %s
-// RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -I %t/Inputs -cxx-interoperability-mode=default -enable-experimental-feature SafeInteropWrappers %t/namespace.swift -dump-macro-expansions -typecheck -verify
+// RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -I %t/Inputs -cxx-interoperability-mode=default -enable-experimental-feature SafeInteropWrappers %t/namespace.swift -emit-module -verify
+// RUN: %target-swift-ide-test -plugin-path %swift-plugin-dir -I %t/Inputs -cxx-interoperability-mode=upcoming-swift -enable-experimental-feature SafeInteropWrappers -print-module -module-to-print=Namespace -source-filename=x > %t/interface.txt
+// RUN: diff %t/interface.txt %t/interface.txt.expected
 
-// CHECK: enum foo {
-// CHECK:  static func bar(_ p: UnsafeMutableBufferPointer<Float>)
+//--- interface.txt.expected
+@_exported import Namespace.Baz
 
+enum foo {
+  static func foo_func(_ p: UnsafeMutablePointer<Float>!, _ len: Int32)
+  /// This is an auto-generated wrapper for safer interop
+  @_alwaysEmitIntoClient @_disfavoredOverload public static func foo_func(_ p: UnsafeMutableBufferPointer<Float>)
+  static func foo_func2(_ p: UnsafePointer<baz_t>!, _ len: baz_t)
+  /// This is an auto-generated wrapper for safer interop
+  @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+  @_alwaysEmitIntoClient @_disfavoredOverload public static func foo_func2(_ p: Span<baz_t>)
+  enum bar {
+    static func bar_func(_ p: UnsafePointer<baz_t>!, _ len: baz_t)
+    /// This is an auto-generated wrapper for safer interop
+    @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+    @_alwaysEmitIntoClient @_disfavoredOverload public static func bar_func(_ p: Span<baz_t>)
+  }
+}
 //--- Inputs/module.modulemap
 module Namespace {
     header "namespace.h"
     requires cplusplus
+    module Baz {
+      header "baz.h"
+    }
 }
 
 //--- Inputs/namespace.h
+#include "baz.h"
+
+#define __counted_by(x) __attribute__((__counted_by__(x)))
+#define __noescape __attribute__((noescape))
 
 namespace foo {
-   __attribute__((swift_attr("@_SwiftifyImport(.countedBy(pointer: .param(1), count: \"len\"))"))) void bar(float *p, int len);
+  __attribute__((swift_attr("@_SwiftifyImport(.countedBy(pointer: .param(1), count: \"len\"))"))) void foo_func(float *p, int len);
+  void foo_func2(const baz_t * __counted_by(len) p __noescape, baz_t len);
+  namespace bar {
+    void bar_func(const baz_t * __counted_by(len) p __noescape, baz_t len);
+  }
 }
 
+//--- Inputs/baz.h
+typedef int baz_t;
+
 //--- namespace.swift
 import Namespace
-  
+
 func test(s: UnsafeMutableBufferPointer<Float>) {
-  foo.bar(s)
-}    
+  foo.foo_func(s)
+}
+
+func test2(s: Span<CInt>) {
+  foo.foo_func2(s)
+}
+
+func test3(s: Span<CInt>) {
+  foo.bar.bar_func(s)
+}
diff --git a/test/Interop/Cxx/swiftify-import/counted-by-method.swift b/test/Interop/Cxx/swiftify-import/counted-by-method.swift
index c15cd8564bc88..625b225ee30b9 100644
--- a/test/Interop/Cxx/swiftify-import/counted-by-method.swift
+++ b/test/Interop/Cxx/swiftify-import/counted-by-method.swift
@@ -27,4 +27,4 @@ import Method
 func test(s: UnsafeMutableBufferPointer<Float>) {
   var foo = Foo()
   foo.bar(s)
-}    
+}
diff --git a/test/Interop/Cxx/swiftify-import/import-as-instance-method.swift b/test/Interop/Cxx/swiftify-import/import-as-instance-method.swift
new file mode 100644
index 0000000000000..c2e9d579bab79
--- /dev/null
+++ b/test/Interop/Cxx/swiftify-import/import-as-instance-method.swift
@@ -0,0 +1,312 @@
+// REQUIRES: rdar162106619
+
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/Test.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers -strict-memory-safety -warnings-as-errors -Xcc -Werror %t/test.swift  -cxx-interoperability-mode=default -Xcc -std=c++20 -verify -verify-additional-file %t/Inputs/instance.h -DVERIFY
+// RUN: env SWIFT_BACKTRACE="" %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/Test.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers -strict-memory-safety -warnings-as-errors -Xcc -Werror %t/test.swift -cxx-interoperability-mode=default -Xcc -std=c++20 -dump-macro-expansions 2>&1 | %FileCheck %s --match-full-lines --strict-whitespace --implicit-check-not __swiftmacro
+
+//--- test.swift
+import Instance
+
+func foo(_ p: inout MutableSpan<CInt>, a: A, aa: inout A, s: IntSpan, cs: ConstIntSpan, asp: AliasingSpan, b: inout baz.B) {
+  aa.basic(&p)
+  aa.bar(&p)
+  a.constSelf(&p)
+  a.valSelf(&p)
+  aa.refSelf(&p)
+  aa.namespaced(&p)
+  b.decapseman(&p)
+  baz.bar(&aa, &p)
+  baz.this(&aa, &p)
+
+  let _: IntSpan = unsafe s.spanSelf()
+  let _: MutableSpan<CInt> = unsafe s.spanSelf()
+  let _: IntSpan = unsafe s.spanConstSelf()
+  let _: MutableSpan<CInt> = unsafe s.spanConstSelf()
+  let _: ConstIntSpan = unsafe cs.constSpanSelf()
+  let _: Span<CInt> = unsafe cs.constSpanSelf()
+  let _: IntSpan = unsafe asp.spanSelf()
+  let _: MutableSpan<CInt> = unsafe asp.spanSelf()
+#if VERIFY
+  p.spanSelf() // expected-error{{value of type 'MutableSpan<CInt>' (aka 'MutableSpan<Int32>') has no member 'spanSelf'}}
+#endif
+}
+
+//--- Inputs/instance.h
+#include <ptrcheck.h>
+#include <lifetimebound.h>
+#include <span>
+
+struct A {};
+
+using IntSpan = std::span<int>;
+using ConstIntSpan = std::span<const int>;
+using AliasingSpan = std::span<int>;
+
+void basic(A *a, IntSpan p __noescape) __attribute__((swift_name("A.basic(self:_:)")));
+
+void renamed(A *a, IntSpan p __noescape) __attribute__((swift_name("A.bar(self:_:)")));
+
+void constSelf(const A *a, IntSpan p __noescape) __attribute__((swift_name("A.constSelf(self:_:)")));
+
+void valSelf(A a, IntSpan p __noescape) __attribute__((swift_name("A.valSelf(self:_:)")));
+
+void refSelf(A &a, IntSpan p __noescape) __attribute__((swift_name("A.refSelf(self:_:)")));
+
+IntSpan spanSelf(IntSpan p __lifetimebound) __attribute__((swift_name("IntSpan.spanSelf(self:)")));
+
+const IntSpan spanConstSelf(const IntSpan p __lifetimebound) __attribute__((swift_name("IntSpan.spanConstSelf(self:)")));
+
+ConstIntSpan constSpanSelf(ConstIntSpan p __lifetimebound) __attribute__((swift_name("ConstIntSpan.constSpanSelf(self:)")));
+
+namespace baz {
+  void namespaced(A *a, IntSpan p __noescape) __attribute__((swift_name("A.namespaced(self:_:)")));
+  struct B {};
+  void renamed(A &a, IntSpan p __noescape) __attribute__((swift_name("baz.bar(_:_:)")));
+  void that(A &a, IntSpan p __noescape) __attribute__((swift_name("this(_:_:)")));
+}
+
+void decapseman(baz::B *b, IntSpan p __noescape) __attribute__((swift_name("baz.B.decapseman(self:_:)")));
+
+//--- Inputs/module.modulemap
+module Instance {
+  header "instance.h"
+  export *
+}
+
+//--- out.expected
+// CHECK:@__swiftmacro_{{.*}}basic{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public mutating func basic(_ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe basic(IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}basic{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "A.basic(self:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func basic(_ a: UnsafeMutablePointer<A>!, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe basic(a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}bar{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public mutating func bar(_ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe bar(IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}renamed{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "A.bar(self:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func renamed(_ a: UnsafeMutablePointer<A>!, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe renamed(a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}constSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func constSelf(_ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe constSelf(IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}constSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "A.constSelf(self:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func constSelf(_ a: UnsafePointer<A>!, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe constSelf(a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}valSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func valSelf(_ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe valSelf(IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}valSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "A.valSelf(self:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func valSelf(_ a: A, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe valSelf(a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}refSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public mutating func refSelf(_ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe refSelf(IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}refSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "A.refSelf(self:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func refSelf(_ a: inout A, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe refSelf(&a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}namespaced{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public mutating func namespaced(_ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe namespaced(IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}baz{{.*}}namespaced{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "A.namespaced(self:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:  public static func namespaced(_ a: UnsafeMutablePointer<A>!, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe namespaced(a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}baz{{.*}}Instance{{.*}}decapseman{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public mutating func decapseman(_ p: inout MutableSpan<CInt>)  {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe decapseman(IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}decapseman{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "baz.B.decapseman(self:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func decapseman(_ b: UnsafeMutablePointer<baz.B>!, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe decapseman(b, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}baz{{.*}}Instance{{.*}}bar{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public static func bar(_ a: inout A, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe bar(&a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}baz{{.*}}renamed{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "baz.bar(_:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:  public static func renamed(_ a: inout A, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe renamed(&a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}baz{{.*}}this{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public static func this(_ a: inout A, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe this(&a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}baz{{.*}}that{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "this(_:_:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:  public static func that(_ a: inout A, _ p: inout MutableSpan<CInt>) {
+// CHECK-NEXT:    return unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe that(&a, IntSpan(_pPtr))
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}Instance{{.*}}spanSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(borrow self) @_disfavoredOverload
+// CHECK-NEXT:public func spanSelf() -> MutableSpan<CInt> {
+// CHECK-NEXT:    return unsafe _swiftifyOverrideLifetime(MutableSpan(_unsafeCxxSpan: unsafe spanSelf()), copying: ())
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_So8spanSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "IntSpan.spanSelf(self:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(copy p) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func spanSelf(_ p: inout MutableSpan<CInt>) -> MutableSpan<CInt> {
+// CHECK-NEXT:    return unsafe _swiftifyOverrideLifetime(MutableSpan(_unsafeCxxSpan: unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe spanSelf(IntSpan(_pPtr))
+// CHECK-NEXT:            }), copying: ())
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}Instance{{.*}}spanConstSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(borrow self) @_disfavoredOverload
+// CHECK-NEXT:public func spanConstSelf() -> MutableSpan<CInt> {
+// CHECK-NEXT:    return unsafe _swiftifyOverrideLifetime(MutableSpan(_unsafeCxxSpan: unsafe spanConstSelf()), copying: ())
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}spanConstSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "IntSpan.spanConstSelf(self:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(copy p) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT:public func spanConstSelf(_ p: inout MutableSpan<CInt>) -> MutableSpan<CInt> {
+// CHECK-NEXT:    return unsafe _swiftifyOverrideLifetime(MutableSpan(_unsafeCxxSpan: unsafe p.withUnsafeMutableBufferPointer { _pPtr in
+// CHECK-NEXT:      return unsafe spanConstSelf(IntSpan(_pPtr))
+// CHECK-NEXT:            }), copying: ())
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}Instance{{.*}}constSpanSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(borrow self) @_disfavoredOverload
+// CHECK-NEXT:public func constSpanSelf() -> Span<CInt> {
+// CHECK-NEXT:    return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe constSpanSelf()), copying: ())
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:@__swiftmacro_{{.*}}constSpanSelf{{.*}}_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@available(swift, obsoleted: 3, renamed: "ConstIntSpan.constSpanSelf(self:)") @_alwaysEmitIntoClient @available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *) @_lifetime(copy p) @_disfavoredOverload
+// CHECK-NEXT:public func constSpanSelf(_ p: Span<CInt>) -> Span<CInt> {
+// CHECK-NEXT:    return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe constSpanSelf(ConstIntSpan(p))), copying: ())
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
diff --git a/test/Interop/Cxx/swiftify-import/span-in-ctor.swift b/test/Interop/Cxx/swiftify-import/span-in-ctor.swift
new file mode 100644
index 0000000000000..e09bcdd2a276f
--- /dev/null
+++ b/test/Interop/Cxx/swiftify-import/span-in-ctor.swift
@@ -0,0 +1,39 @@
+// REQUIRES: rdar162106747
+
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -c -plugin-path %swift-plugin-dir -I %t/Inputs -Xcc -std=c++20 -cxx-interoperability-mode=default -enable-experimental-feature SafeInteropWrappers %t/method.swift -dump-macro-expansions -verify 2>&1 | %FileCheck %s
+
+// CHECK: @_alwaysEmitIntoClient 
+// CHECK: public init(_ sp: Span<CInt>) {
+// CHECK:    unsafe self.init(IntSpan(sp))
+// CHECK: }
+
+
+//--- Inputs/module.modulemap
+module Method {
+    header "method.h"
+    requires cplusplus
+}
+
+//--- Inputs/method.h
+
+#include <span>
+
+using IntSpan = std::span<const int>;
+
+class Foo {
+public:
+   Foo();
+   Foo(IntSpan sp [[clang::noescape]]);
+};
+
+//--- method.swift
+import CxxStdlib
+import Method
+  
+func test(s: Span<Int32>) {
+  var _ = Foo(s)
+}
diff --git a/test/Interop/Cxx/symbolic-imports/indexing-emit-libcxx-no-foundation-symbolic-module-interface.swift b/test/Interop/Cxx/symbolic-imports/indexing-emit-libcxx-no-foundation-symbolic-module-interface.swift
deleted file mode 100644
index eb9ae8d2e37cb..0000000000000
--- a/test/Interop/Cxx/symbolic-imports/indexing-emit-libcxx-no-foundation-symbolic-module-interface.swift
+++ /dev/null
@@ -1,16 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-
-// RUN: %target-swift-frontend %t/test.swift -I %t -c -index-system-modules -index-store-path %t/store -enable-experimental-cxx-interop
-// RUN: ls %t/store/interfaces | %FileCheck --check-prefix=FILES %s
-
-// REQUIRES: OS=macosx
-// REQUIRES: cxx-interop-fixed-cf_options
-
-//--- test.swift
-
-import CxxStdlib
-import Foundation
-
-// FILES: std-{{.*}}.pcm.symbolicswiftinterface
-// FILES-NOT: Foundation*
diff --git a/test/Interop/Cxx/symbolic-imports/indexing-emit-libcxx-symbolic-module-interface.swift b/test/Interop/Cxx/symbolic-imports/indexing-emit-libcxx-symbolic-module-interface.swift
deleted file mode 100644
index c2cd6835048eb..0000000000000
--- a/test/Interop/Cxx/symbolic-imports/indexing-emit-libcxx-symbolic-module-interface.swift
+++ /dev/null
@@ -1,45 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-
-// Verify that symbolic interfaces are emitted.
-//
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-store-path %t/store -enable-experimental-cxx-interop -Rindexing-system-module 2>%t/remarks
-// RUN: echo "EOF" >> %t/remarks
-// RUN: cat %t/remarks | %FileCheck --check-prefix=REMARK_NEW %s
-// RUN: ls %t/store/interfaces | %FileCheck --check-prefix=FILES %s
-// RUN: cat %t/store/interfaces/std* | %FileCheck --check-prefix=CHECK %s
-
-// Verify that symbolic interfaces are not emitted when PCM doesn't change.
-//
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-store-path %t/store -enable-experimental-cxx-interop -Rindexing-system-module 2>&1 | %FileCheck --check-prefix=REMARK_NO_UPDATE %s
-// RUN: ls %t/store/interfaces | %FileCheck --check-prefix=FILES %s
-
-// REQUIRES: OS=macosx
-
-//--- Inputs/module.modulemap
-module CxxModule {
-    header "headerA.h"
-    requires cplusplus
-}
-
-//--- Inputs/headerA.h
-
-int freeFunction(int x, int y);
-
-//--- test.swift
-
-import CxxStdlib
-import CxxModule
-
-// CHECK-NOT: warning: 'import_owned' Swift attribute ignored on type
-
-// REMARK_NEW: remark: emitting symbolic interface at {{.*}}/interfaces/std-{{.*}}.pcm.symbolicswiftinterface{{$}}
-// REMARK_NEW: remark: emitting symbolic interface at {{.*}}/interfaces/CxxModule-{{.*}}.pcm.symbolicswiftinterface{{$}}
-
-// REMARK_NO_UPDATE-NOT: remark: emitting symbolic interface at {{.*}}/interfaces/std-{{.*}}.pcm.symbolicswiftinterface{{$}}
-// REMARK_NO_UPDATE-NOT: remark: emitting symbolic interface at {{.*}}/interfaces/CxxModule-{{.*}}.pcm.symbolicswiftinterface{{$}}
-
-// FILES: CxxModule-{{.*}}.pcm.symbolicswiftinterface
-// FILES: std-{{.*}}.pcm.symbolicswiftinterface
-
-// CHECK: // Swift interface for system module 'std'
diff --git a/test/Interop/Cxx/symbolic-imports/indexing-emit-no-symbolic-module-interface-no-clang-module-index.swift b/test/Interop/Cxx/symbolic-imports/indexing-emit-no-symbolic-module-interface-no-clang-module-index.swift
deleted file mode 100644
index d28aced58f84a..0000000000000
--- a/test/Interop/Cxx/symbolic-imports/indexing-emit-no-symbolic-module-interface-no-clang-module-index.swift
+++ /dev/null
@@ -1,23 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-//
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-ignore-clang-modules -index-store-path %t/store -enable-experimental-cxx-interop -Rindexing-system-module 2>&1 | %FileCheck %s
-// RUN: not ls %t/store/interfaces
-
-//--- Inputs/module.modulemap
-module CxxModule {
-    header "headerA.h"
-    requires cplusplus
-}
-
-//--- Inputs/headerA.h
-
-namespace ns {
-    int freeFunction(int x, int y);
-}
-
-//--- test.swift
-
-import CxxModule
-
-// CHECK-NOT: emitting symbolic interface at
diff --git a/test/Interop/Cxx/symbolic-imports/indexing-emit-objcxx-symbolic-module-interface.swift b/test/Interop/Cxx/symbolic-imports/indexing-emit-objcxx-symbolic-module-interface.swift
deleted file mode 100644
index b318ca0454fce..0000000000000
--- a/test/Interop/Cxx/symbolic-imports/indexing-emit-objcxx-symbolic-module-interface.swift
+++ /dev/null
@@ -1,62 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-store-path %t/store -enable-experimental-cxx-interop -Rindexing-system-module 2>&1 | %FileCheck --check-prefix=REMARK_NEW %s
-// RUN: ls %t/store/interfaces | %FileCheck --check-prefix=FILES %s
-// RUN: cat %t/store/interfaces/ObjCxxModule* | %FileCheck --check-prefix=CHECK %s
-
-
-// Verify that symbolic interface is not emitted without interop.
-//
-// RUN: rm -r %t/store/interfaces
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-store-path %t/store -Rindexing-system-module 2>&1 > %t/out
-// RUN: echo "non-empty-file-check" >> %t/out
-// RUN: cat %t/out | %FileCheck --check-prefix=REMARK_NONE %s
-// RUN: not ls %t/store/interfaces
-
-// REQUIRES: objc_interop
-// REQUIRES: cxx-interop-fixed-cf_options
-
-//--- Inputs/module.modulemap
-module ObjCxxModule {
-    header "headerA.h"
-    // NOTE: does not require cplusplus
-}
-
-//--- Inputs/headerA.h
-
-#include <Foundation/Foundation.h>
-
-#ifdef __cplusplus
-namespace ns {
-    int freeCxxFunction(int x, int y);
-}
-#endif
-
-@interface ObjCClass: NSObject
-
-- (void)myTestMethod;
-
-@end
-
-//--- test.swift
-
-import ObjCxxModule
-
-// REMARK_NEW: remark: emitting symbolic interface at {{.*}}/interfaces/ObjCxxModule-{{.*}}.pcm.symbolicswiftinterface{{$}}
-// REMARK_NONE-NOT: emitting symbolic interface at
-
-// FILES: ObjCxxModule-{{.*}}.pcm.symbolicswiftinterface
-
-// CHECK: // Swift interface for module 'ObjCxxModule'
-// CHECK-NEXT: import Foundation
-// CHECK-EMPTY:
-// CHECK-NEXT: public enum ns {
-// CHECK-EMPTY:
-// CHECK-NEXT:     public static func freeCxxFunction(_ x: Int32, _ y: Int32) -> Int32
-// CHECK-NEXT: }
-// CHECK-EMPTY:
-// CHECK-NEXT: open class ObjCClass : NSObject {
-// CHECK-EMPTY:
-// CHECK-NEXT:     open func myTestMethod()
-// CHECK-NEXT: }
diff --git a/test/Interop/Cxx/symbolic-imports/indexing-emit-symbolic-module-interface-used-decls.swift b/test/Interop/Cxx/symbolic-imports/indexing-emit-symbolic-module-interface-used-decls.swift
deleted file mode 100644
index 4b9021a8e742e..0000000000000
--- a/test/Interop/Cxx/symbolic-imports/indexing-emit-symbolic-module-interface-used-decls.swift
+++ /dev/null
@@ -1,45 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-store-path %t/store -enable-experimental-cxx-interop 2>&1
-// RUN: cat %t/store/interfaces/CxxModule* | %FileCheck --check-prefix=CHECK %s
-
-//--- Inputs/module.modulemap
-module CxxModule {
-    header "header.h"
-    requires cplusplus
-}
-
-//--- Inputs/header.h
-
-namespace ns {
-    template<class T>
-    struct TemplateRecord {
-        void methodFunc(int x) const;
-    };
-}
-
-using TemplateRecordInt = ns::TemplateRecord<int>;
-
-//--- test.swift
-
-import CxxModule
-
-public func useConcreteTemplate() {
-    let x = TemplateRecordInt()
-    x.methodFunc(2)
-}
-
-// CHECK: // Swift interface for module 'CxxModule'
-// CHECK:     public enum ns {
-// CHECK-EMPTY:
-// CHECK-NEXT: public struct TemplateRecord {
-// CHECK-EMPTY:
-// CHECK-NEXT:    @available(*, deprecated, message:
-// CHECK-NEXT:    public init()
-// CHECK-EMPTY:
-// CHECK-NEXT:    public func methodFunc(_ x: Any)
-// CHECK-NEXT:}
-// CHECK-NEXT:}
-// CHECK-EMPTY:
-// CHECK-NEXT: public typealias TemplateRecordInt = ns.TemplateRecord
diff --git a/test/Interop/Cxx/symbolic-imports/indexing-emit-symbolic-module-interface.swift b/test/Interop/Cxx/symbolic-imports/indexing-emit-symbolic-module-interface.swift
deleted file mode 100644
index 42f211323fe9a..0000000000000
--- a/test/Interop/Cxx/symbolic-imports/indexing-emit-symbolic-module-interface.swift
+++ /dev/null
@@ -1,164 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-
-// Verify that symbolic interfaces are emitted.
-//
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-store-path %t/store -enable-experimental-cxx-interop -Rindexing-system-module 2>%t/remarks
-// RUN: echo "EOF" >> %t/remarks
-// RUN: cat %t/remarks | %FileCheck --check-prefixes=REMARK_NEW,REMARK_INITIAL %s
-// RUN: ls %t/store/interfaces | %FileCheck --check-prefix=FILES %s
-// RUN: cat %t/store/interfaces/CxxModule* | %FileCheck --check-prefix=CHECK %s
-
-// Verify that symbolic interfaces are not emitted when PCM doesn't change.
-//
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-store-path %t/store -enable-experimental-cxx-interop -Rindexing-system-module 2>&1 | %FileCheck --check-prefix=REMARK_NO_UPDATE %s
-// RUN: ls %t/store/interfaces | %FileCheck --check-prefix=FILES %s
-// RUN: cat %t/store/interfaces/CxxModule* | %FileCheck --check-prefix=CHECK %s
-
-// Verify that symbolic interface is re-emitted when the interface is removed.
-//
-// RUN: rm -r %t/store/interfaces
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-store-path %t/store -enable-experimental-cxx-interop -Rindexing-system-module 2>&1 | %FileCheck --check-prefix=REMARK_NEW %s
-// RUN: ls %t/store/interfaces | %FileCheck --check-prefix=FILES %s
-// RUN: cat %t/store/interfaces/CxxModule* | %FileCheck --check-prefixes=CHECK %s
-
-// Verify that symbolic interface is re-emitted when PCM changes.
-//
-// RUN: echo "using AdditionalAlias = int;" >> %t/Inputs/headerA.h
-// RUN: %target-swift-frontend %t/test.swift -I %t/Inputs -c -index-system-modules -index-store-path %t/store -enable-experimental-cxx-interop -Rindexing-system-module 2>&1 | %FileCheck --check-prefix=REMARK_NEW %s
-// RUN: ls %t/store/interfaces | %FileCheck --check-prefix=FILES %s
-// RUN: cat %t/store/interfaces/CxxModule* | %FileCheck --check-prefixes=CHECK,CHECK-UPDATED %s
-
-//--- Inputs/module.modulemap
-module CxxModule {
-    header "headerA.h"
-    header "headerB.h"
-    requires cplusplus
-}
-
-module TransitiveCppMod {
-    header "transitiveHeader.h"
-    requires cplusplus
-}
-
-//--- Inputs/headerA.h
-
-namespace ns {
-    int freeFunction(int x, int y);
-}
-
-//--- Inputs/transitiveHeader.h
-
-template<class T>
-struct TransitiveStruct {
-    T x;
-
-    void test() {}
-};
-
-//--- Inputs/headerB.h
-
-#include "headerA.h"
-#include "transitiveHeader.h"
-
-namespace ns {
-    struct B {
-        int y;
-    };
-
-    template<class T>
-    struct TemplateRecord {
-        void methodFunc(int x);
-
-        struct InnerRecord {
-            int innerMethod(int y);
-        };
-
-        template<class T2>
-        struct InnerTemplate {
-            void innerTemplateMethod();
-        };
-
-        InnerTemplate<int> returnsTemplateMethod();
-    };
-
-    inline namespace __1 {
-        struct StructInInlineNamespace {
-        };
-
-        using TypealiasInInlineNamespace = TemplateRecord<StructInInlineNamespace>;
-    }
-
-    using TypealiasOfInlineNamespace = __1::StructInInlineNamespace;
-}
-
-using MyType = ns::TemplateRecord<int>;
-using MyType2 = TransitiveStruct<int>;
-
-//--- test.swift
-
-import CxxModule
-
-// REMARK_INITIAL: remark: emitting symbolic interface at {{.*}}{{/|\\}}interfaces{{/|\\}}CxxShim-{{.*}}.pcm.symbolicswiftinterface{{$}}
-// REMARK_NEW: remark: emitting symbolic interface at {{.*}}{{/|\\}}interfaces{{/|\\}}CxxModule-{{.*}}.pcm.symbolicswiftinterface{{$}}
-// REMARK_INITIAL-NEXT: EOF
-
-// REMARK_NO_UPDATE: remark: emitting symbolic interface at {{.*}}{{/|\\}}interfaces{{/|\\}}CxxModule-{{.*}}.pcm.symbolicswiftinterface; skipping because it's up to date{{$}}
-
-// FILES: CxxModule-{{.*}}.pcm.symbolicswiftinterface
-// FILES-NOT: TransitiveCppMod
-
-// CHECK: // Swift interface for module 'CxxModule'
-// CHECK-UPDATED: typealias AdditionalAlias =
-// CHECK:     enum ns {
-// CHECK-EMPTY:
-// CHECK-NEXT: struct B {
-// CHECK-EMPTY:
-// CHECK-NEXT:    init()
-// CHECK-EMPTY:
-// CHECK-NEXT:    init(y: Int32)
-// CHECK-EMPTY:
-// CHECK-NEXT:    var y: Int32
-// CHECK-NEXT:  }
-// CHECK-EMPTY:
-// CHECK-NEXT:  struct TemplateRecord {
-// CHECK-EMPTY:
-// CHECK-NEXT:    @available(*, deprecated, message:
-// CHECK-NEXT:    public init()
-// CHECK-EMPTY:
-// CHECK-NEXT:    mutating func methodFunc(_ x: Any)
-// CHECK-EMPTY:
-// CHECK-NEXT:    struct InnerRecord {
-// CHECK-EMPTY:
-// CHECK-NEXT:      @available(*, deprecated, message:
-// CHECK-NEXT:      public init()
-// CHECK-EMPTY:
-// CHECK-NEXT:      mutating func innerMethod(_ y: Any)
-// CHECK-NEXT:    }
-// CHECK-EMPTY:
-// CHECK-NEXT:    struct InnerTemplate {
-// CHECK-EMPTY:
-// CHECK-NEXT:    @available(*, deprecated, message:
-// CHECK-NEXT:    public init()
-// CHECK-EMPTY:
-// CHECK-NEXT:      mutating func innerTemplateMethod()
-// CHECK-NEXT:    }
-// CHECK-EMPTY:
-// CHECK-NEXT:    mutating func returnsTemplateMethod()
-// CHECK-NEXT:  }
-// CHECK:       public struct StructInInlineNamespace {
-// CHECK-EMPTY:
-// CHECK-NEXT:    public init()
-// CHECK-NEXT:  }
-// CHECK-EMPTY:
-// CHECK-NEXT:  public typealias TypealiasInInlineNamespace = ns.TemplateRecord
-// CHECK-EMPTY:
-// CHECK-EMPTY:
-// CHECK-NEXT:  public typealias TypealiasOfInlineNamespace = ns.StructInInlineNamespace
-// CHECK-EMPTY:
-// CHECK-NEXT:  static func freeFunction(_ x: Int32, _ y: Int32) -> Int32
-// CHECK-NEXT: }
-// CHECK-EMPTY:
-// CHECK-NEXT: typealias MyType = ns.TemplateRecord
-// CHECK-EMPTY:
-// CHECK-NEXT: typealias MyType2 = TransitiveStruct
diff --git a/test/Interop/Cxx/symbolic-imports/print-symbolic-module-interface.swift b/test/Interop/Cxx/symbolic-imports/print-symbolic-module-interface.swift
deleted file mode 100644
index 21fdcbefd8cac..0000000000000
--- a/test/Interop/Cxx/symbolic-imports/print-symbolic-module-interface.swift
+++ /dev/null
@@ -1,127 +0,0 @@
-// RUN: rm -rf %t
-// RUN: split-file %s %t
-// RUN: %target-swift-ide-test -print-module -module-to-print=CxxModule -I %t/Inputs -source-filename=x -enable-experimental-cxx-interop -enable-experimental-feature ImportSymbolicCXXDecls 2>&1 | %FileCheck %s
-
-// REQUIRES: swift_feature_ImportSymbolicCXXDecls
-
-//--- Inputs/module.modulemap
-module CxxModule {
-    header "headerA.h"
-    header "headerB.h"
-    requires cplusplus
-}
-
-//--- Inputs/headerA.h
-
-namespace ns {
-    int freeFunction(int x, int y);
-}
-
-//--- Inputs/headerB.h
-
-#include "headerA.h"
-
-namespace ns {
-    struct B {
-        int y;
-    };
-
-    template<class T>
-    struct TemplateRecord {
-        void methodFunc(int x);
-
-        struct InnerRecord {
-            int innerMethod(int y);
-        };
-
-        template<class T2>
-        struct InnerTemplate {
-            void innerTemplateMethod();
-            void innerTemplateMethodWithDefaultArg(T2 x = 123);
-        };
-
-        InnerTemplate<int> returnsTemplateMethod();
-    };
-}
-
-using MyType = ns::TemplateRecord<int>;
-
-template<class X>
-class OuterTemp2 {
-public:
-    template<class T, class G>
-    class InnerTemp2 {
-    public:
-        void testMe(const T& p, const X& x);
-
-        X x2;
-
-        using Y = X;
-    };
-};
-
-template <class T>
-struct __attribute__((swift_attr("import_owned"))) AnnotatedTemplate {
-    T t;
-};
-
-#define IMMORTAL_FRT                                                         \
-    __attribute__((swift_attr("import_reference")))                              \
-    __attribute__((swift_attr("retain:immortal")))                               \
-    __attribute__((swift_attr("release:immortal")))
-
-struct IMMORTAL_FRT MyImmortal {
-    virtual void foo() const {};
-};
-
-struct NonCopyable {
-    NonCopyable(const NonCopyable& other) = delete;
-};
-
-// CHECK-NOT: warning: 'import_owned' Swift attribute ignored on type
-
-// CHECK:     enum ns {
-// CHECK-NEXT: struct B {
-// CHECK-NEXT:    init()
-// CHECK-NEXT:    init(y: Int32)
-// CHECK-NEXT:    var y: Int32
-// CHECK-NEXT:  }
-// CHECK-NEXT:  struct TemplateRecord {
-// CHECK-NEXT:    @available(*, deprecated, message:
-// CHECK-NEXT:    init()
-// CHECK-NEXT:    mutating func methodFunc(_ x: Any)
-// CHECK-NEXT:    struct InnerRecord {
-// CHECK-NEXT:      @available(*, deprecated, message:
-// CHECK-NEXT:      init()
-// CHECK-NEXT:      mutating func innerMethod(_ y: Any)
-// CHECK-NEXT:    }
-// CHECK-NEXT:    struct InnerTemplate {
-// CHECK-NEXT:      @available(*, deprecated, message:
-// CHECK-NEXT:      init()
-// CHECK-NEXT:      mutating func innerTemplateMethod()
-// CHECK-NEXT:      mutating func innerTemplateMethodWithDefaultArg(_ x: Any = cxxDefaultArg)
-// CHECK-NEXT:    }
-// CHECK-NEXT:    mutating func returnsTemplateMethod()
-// CHECK-NEXT:  }
-// CHECK-NEXT:  static func freeFunction(_ x: Int32, _ y: Int32) -> Int32
-// CHECK-NEXT: }
-// CHECK-NEXT: typealias MyType = ns.TemplateRecord
-// CHECK-NEXT: struct OuterTemp2 {
-// CHECK-NEXT:   @available(*, deprecated, message:
-// CHECK-NEXT:   init()
-// CHECK-NEXT:   struct InnerTemp2 {
-// CHECK-NEXT:     @available(*, deprecated, message:
-// CHECK-NEXT:     init()
-// CHECK-NEXT:     init(x2: Any)
-// CHECK-NEXT:     mutating func testMe(_ p: Any, _ x: Any)
-// CHECK-NEXT:     var x2: Any
-// CHECK-NEXT:     typealias Y = Any
-// CHECK-NEXT:   }
-// CHECK-NEXT: }
-// CHECK: class MyImmortal {
-// CHECK-NEXT:   func foo()
-// CHECK-NEXT: }
-// CHECK-NEXT: struct NonCopyable {
-// CHECK-NEXT:   @available(*, deprecated, message:
-// CHECK-NEXT:   init()
-// CHECK-NEXT: }
diff --git a/test/Interop/Cxx/templates/Inputs/ForwardDeclaredSpecialization.h b/test/Interop/Cxx/templates/Inputs/ForwardDeclaredSpecialization.h
new file mode 100644
index 0000000000000..9ac3ee1dcac9a
--- /dev/null
+++ b/test/Interop/Cxx/templates/Inputs/ForwardDeclaredSpecialization.h
@@ -0,0 +1,63 @@
+#ifndef FORWARD_DECLARED_SPECIALIZATION_H
+#define FORWARD_DECLARED_SPECIALIZATION_H
+
+// Basic template definition
+template <typename T>
+struct BasicTemplate {
+  T value;
+};
+
+// Case 1: Forward-declared specialization (should NOT import)
+template <>
+struct BasicTemplate<int>;
+typedef BasicTemplate<int> ForwardDeclaredInt;
+
+// Case 2: Complete specialization (should import successfully)
+template <>
+struct BasicTemplate<double> {
+  double value;
+  double getValue() const { return value; }
+};
+typedef BasicTemplate<double> CompleteDouble;
+
+// Case 3: Specialization defined after typedef (should import)
+template <>
+struct BasicTemplate<float>;
+typedef BasicTemplate<float> FloatTypedef;
+
+template <>
+struct BasicTemplate<float> {
+  float value;
+};
+
+// Case 4: For comparison - forward-declared non-templated struct (have same behavior)
+struct ForwardDeclaredStruct;
+typedef ForwardDeclaredStruct ForwardDeclaredStructType;
+
+// Case 5: Complete non-templated struct (imports successfully)
+struct CompleteStruct {
+  int value;
+};
+typedef CompleteStruct CompleteStructType;
+
+// Template for partial specialization test
+template <typename T, typename U>
+struct PartialTemplate {
+  T first;
+  U second;
+};
+
+// Case 6: Forward-declared partial specialization (should NOT import - same as explicit)
+template <typename T>
+struct PartialTemplate<T*, int>;  // Forward declaration only
+typedef PartialTemplate<double*, int> ForwardDeclaredPartial;
+
+// Case 7: Complete partial specialization (should import successfully)
+template <typename T>
+struct PartialTemplate<T*, double> {
+  T* ptr;
+  double value;
+};
+typedef PartialTemplate<int*, double> CompletePartial;
+
+#endif
diff --git a/test/Interop/Cxx/templates/Inputs/function-templates.h b/test/Interop/Cxx/templates/Inputs/function-templates.h
index 16c0472629129..a2a9d8da0a774 100644
--- a/test/Interop/Cxx/templates/Inputs/function-templates.h
+++ b/test/Interop/Cxx/templates/Inputs/function-templates.h
@@ -15,8 +15,27 @@ template <class T> void expectsConstCharPtr(T str) { takesString(str); }
 template <long x> void hasNonTypeTemplateParameter() {}
 template <long x = 0> void hasDefaultedNonTypeTemplateParameter() {}
 
+// NOTE: these will cause multi-def linker errors if used in more than one compilation unit
 int *intPtr;
-int (*functionPtr)(void);
+
+int get42(void) { return 42; }
+int (*functionPtrGet42)(void) = &get42;
+int (*_Nonnull nonNullFunctionPtrGet42)(void) = &get42;
+
+int tripleInt(int x) { return x * 3; }
+int (*functionPtrTripleInt)(int) = &tripleInt;
+int (*_Nonnull nonNullFunctionPtrTripleInt)(int) = &tripleInt;
+
+int (^blockReturns111)(void) = ^{ return 111; };
+int (^_Nonnull nonNullBlockReturns222)(void) = ^{ return 222; };
+
+int (^blockTripleInt)(int) = ^(int x) { return x * 3; };
+int (^_Nonnull nonNullBlockTripleInt)(int) = ^(int x) { return x * 3; };
+
+// These functions construct block literals that capture a local variable, and
+// then feed those blocks back to Swift via the given Swift closure (cb).
+void getConstantIntBlock(int returnValue, void (^_Nonnull cb)(int (^_Nonnull)(void))) { cb(^{ return returnValue; }); }
+int getMultiplyIntBlock(int multiplier, int (^_Nonnull cb)(int (^_Nonnull)(int))) { return cb(^(int x) { return x * multiplier; }); }
 
 // We cannot yet use this in Swift but, make sure we don't crash when parsing
 // it.
@@ -59,6 +78,7 @@ struct PlainStruct {
 struct CxxClass {
   int x;
   void method() {}
+  int getX() const { return x; }
 };
 
 struct __attribute__((swift_attr("import_reference")))
@@ -100,7 +120,24 @@ template <class T> bool constLvalueReferenceToBool(const T &t) { return t; }
 
 template <class T> void forwardingReference(T &&) {}
 
-template <class T> void PointerTemplateParameter(T*){}
+template <class T> bool pointerTemplateParameter(T *t) { return t; }
+template <class T> bool pointerTemplateParameterNonnull(T *_Nonnull t) { return t; }
+template <class T> bool pointerTemplateParameterNullable(T *_Nullable t) { return t; }
+
+template <typename F> void callFunction(F f) { f(); }
+template <typename F, typename T> void callFunctionWithParam(F f, T t) { f(t); }
+template <typename F, typename T> T callFunctionWithReturn(F f) { return f(); }
+template <typename F, typename T> T callFunctionWithPassthrough(F f, T t) { return f(t); }
+
+static inline void callBlock(void (^_Nonnull callback)(void)) { callback(); }
+template <typename F> void indirectlyCallFunction(F f) { callBlock(f); }
+template <typename F> void indirectlyCallFunctionTemplate(F f) { callFunction(f); }
+
+static inline void callBlockWith42(void (^_Nonnull callback)(int)) { callback(42); }
+template <typename F> void indirectlyCallFunctionWith42(F f) { callBlockWith42(f); }
+
+static inline void callBlockWithCxxClass24(void (^_Nonnull cb)(CxxClass)) { CxxClass c = {24}; cb(c); }
+template <typename F> void indirectlyCallFunctionWithCxxClass24(F f) { callBlockWithCxxClass24(f); }
 
 namespace Orbiters {
 
diff --git a/test/Interop/Cxx/templates/Inputs/module.modulemap b/test/Interop/Cxx/templates/Inputs/module.modulemap
index fef23854e1c09..720ea7fc9da7f 100644
--- a/test/Interop/Cxx/templates/Inputs/module.modulemap
+++ b/test/Interop/Cxx/templates/Inputs/module.modulemap
@@ -172,3 +172,18 @@ module ManySpecializations {
   header "many-specializations.h"
   requires cplusplus
 }
+
+module UninstantiatableSpecialMembers {
+  header "uninstantiatable-special-members.h"
+  requires cplusplus
+}
+
+module VariableTemplate {
+  header "variable-template.h"
+  requires cplusplus
+}
+
+module ForwardDeclaredSpecialization {
+  header "ForwardDeclaredSpecialization.h"
+  requires cplusplus
+}
diff --git a/test/Interop/Cxx/templates/Inputs/uninstantiatable-special-members.h b/test/Interop/Cxx/templates/Inputs/uninstantiatable-special-members.h
new file mode 100644
index 0000000000000..03992368fa392
--- /dev/null
+++ b/test/Interop/Cxx/templates/Inputs/uninstantiatable-special-members.h
@@ -0,0 +1,27 @@
+template <class T>
+struct __attribute__((swift_attr("~Copyable"))) HasUninstantiatableCopyConstructor {
+  template <class U>
+  void scaryPoison(U u) {
+    U::doesNotExist(u);
+  }
+
+  int value;
+  HasUninstantiatableCopyConstructor(int value) : value(value) {}
+  HasUninstantiatableCopyConstructor(
+      const HasUninstantiatableCopyConstructor &other) {
+    scaryPoison(other);
+  }
+  HasUninstantiatableCopyConstructor(
+      HasUninstantiatableCopyConstructor &&other) = default;
+};
+
+typedef HasUninstantiatableCopyConstructor<int> NonCopyableInst;
+
+template <class T>
+struct __attribute__((swift_attr("~Copyable"))) DerivedUninstantiatableCopyConstructor : HasUninstantiatableCopyConstructor<T> {
+  DerivedUninstantiatableCopyConstructor(int value) : HasUninstantiatableCopyConstructor<T>(value) {}
+  DerivedUninstantiatableCopyConstructor(const DerivedUninstantiatableCopyConstructor &other) = default;
+  DerivedUninstantiatableCopyConstructor(DerivedUninstantiatableCopyConstructor &&other) = default;
+};
+
+typedef DerivedUninstantiatableCopyConstructor<int> DerivedNonCopyableInst;
diff --git a/test/Interop/Cxx/templates/Inputs/variable-template.h b/test/Interop/Cxx/templates/Inputs/variable-template.h
new file mode 100644
index 0000000000000..ffe1432a24199
--- /dev/null
+++ b/test/Interop/Cxx/templates/Inputs/variable-template.h
@@ -0,0 +1,5 @@
+template <int N, int M>
+inline const int template_gcd = template_gcd<M, N % M>;
+
+template <int N>
+inline const int template_gcd<N, 0> = N;
diff --git a/test/Interop/Cxx/templates/defaulted-template-type-parameter-module-interface.swift b/test/Interop/Cxx/templates/defaulted-template-type-parameter-module-interface.swift
index 45cbddf4d0531..7d7f7c70895db 100644
--- a/test/Interop/Cxx/templates/defaulted-template-type-parameter-module-interface.swift
+++ b/test/Interop/Cxx/templates/defaulted-template-type-parameter-module-interface.swift
@@ -21,6 +21,6 @@
 // TODO-CHECK: func defaultedTemplatePointerTypeParam<T>(_ t: UnsafeMutablePointer<T>)
 // TODO-CHECK: func defaultedTemplatePointerPointerTypeParam<T>(_ t: UnsafeMutablePointer<OpaquePointer?>!)
 
-// CHECK: func defaultedTemplatePointerTypeParam<T>(_ t: UnsafeMutablePointer<T>)
+// CHECK: func defaultedTemplatePointerTypeParam<T>(_ t: UnsafeMutablePointer<T>!)
 // We don't support references to dependent types (rdar://89034440).
 // CHECK-NOT: defaultedTemplatePointerReferenceTypeParam
diff --git a/test/Interop/Cxx/templates/explicit-class-specialization-module-interface.swift b/test/Interop/Cxx/templates/explicit-class-specialization-module-interface.swift
index d3306aeeb38a8..bcc26322796e8 100644
--- a/test/Interop/Cxx/templates/explicit-class-specialization-module-interface.swift
+++ b/test/Interop/Cxx/templates/explicit-class-specialization-module-interface.swift
@@ -5,5 +5,5 @@
 // CHECK: }
 
 // CHECK: struct HasEmptySpecializationAndStaticDateMember<CChar> {
-// CHECK:   static let value: Bool
+// CHECK:   static var value: Bool { get }
 // CHECK: }
diff --git a/test/Interop/Cxx/templates/forward-declared-specialization.swift b/test/Interop/Cxx/templates/forward-declared-specialization.swift
new file mode 100644
index 0000000000000..3f3080e048feb
--- /dev/null
+++ b/test/Interop/Cxx/templates/forward-declared-specialization.swift
@@ -0,0 +1,32 @@
+// RUN: %target-typecheck-verify-swift -I %S/Inputs -cxx-interoperability-mode=default
+
+import ForwardDeclaredSpecialization
+
+func testForwardDeclaredSpecialization(_ param: ForwardDeclaredInt) {
+  // expected-error@-1 {{cannot find type 'ForwardDeclaredInt' in scope}}
+}
+
+func testCompleteSpecialization(_ param: CompleteDouble) {
+  let _ = param.getValue()
+}
+
+func testSpecializationDefinedAfter(_ param: FloatTypedef) {
+  let _ = param.value
+}
+
+func testForwardDeclaredStruct(_ param: ForwardDeclaredStructType) {
+  // expected-error@-1 {{cannot find type 'ForwardDeclaredStructType' in scope}}
+}
+
+func testCompleteStruct(_ param: CompleteStructType) {
+  let _ = param.value
+}
+
+func testForwardDeclaredPartial(_ param: ForwardDeclaredPartial) {
+  // expected-error@-1 {{cannot find type 'ForwardDeclaredPartial' in scope}}
+}
+
+func testCompletePartial(_ param: CompletePartial) {
+  let _ = param.ptr
+  let _ = param.value
+}
diff --git a/test/Interop/Cxx/templates/function-template-closures.swift b/test/Interop/Cxx/templates/function-template-closures.swift
new file mode 100644
index 0000000000000..d473919035830
--- /dev/null
+++ b/test/Interop/Cxx/templates/function-template-closures.swift
@@ -0,0 +1,146 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -cxx-interoperability-mode=default)
+
+// REQUIRES: executable_test
+// REQUIRES: objc_interop
+
+import FunctionTemplates
+import StdlibUnittest
+
+var FunctionTemplateClosuresTestSuite = TestSuite("Function Templates with Closures")
+
+FunctionTemplateClosuresTestSuite.test("callFunction<F> where F == () -> ()") {
+  var value = false
+  callFunction({() in value = true})
+  expectTrue(value)
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunction<F> where F == () -> Bool") {
+  var value = false
+  callFunction({() in value = true; return true})
+  expectTrue(value)
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithParam<F, T> where F == (Int) -> (), T == Int") {
+  var value = 42
+  callFunctionWithParam({(x: Int) in value = x}, 24)
+  expectEqual(value, 24)
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithParam<F, T> where F == (Int) -> Bool, T == Int") {
+  var value = 42
+  callFunctionWithParam({(x: Int) in value = x; return true}, 24)
+  expectEqual(value, 24)
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithParam<F, T> where F == (CxxClass) -> (), T == CxxClass") {
+  var value: CInt = 42
+
+  // Read x via direct field access
+  callFunctionWithParam({(c: CxxClass) in value = c.x}, CxxClass(x: 24))
+  expectEqual(value, 24)
+
+  // Read x via getter method
+  callFunctionWithParam({(c: CxxClass) in value = c.getX()}, CxxClass(x: 22))
+  expectEqual(value, 22)
+}
+
+// TODO: this likely needs more design work
+// FunctionTemplateClosuresTestSuite.test("callFunctionWithParam<F, T> where F == (()) -> (), T == ()") {
+//   var value = 42
+//   // None of these are quite right:
+//   // callFunctionWithParam({(_: ()) in value = 24}, ())
+//   // callFunctionWithParam({(_: Void) in value = 24}, ())
+//   // callFunctionWithParam({() in value = 24}, ())
+//   expectEqual(value, 24)
+// }
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithReturn<F, T> where F == () -> Int, T == Int") {
+  let val1: Int = callFunctionWithReturn({() in 111})
+  expectEqual(val1, 111)
+  let val2: Int = callFunctionWithReturn({() -> Int in 222})
+  expectEqual(val2, 222)
+  // Cannot infer return type without val3 explicitly annotated as Int
+  // let val3 = callFunctionWithReturn({() -> Int in 333})
+  // expectEqual(val3, 333)
+
+  // This works:
+  expectEqual(callFunctionWithReturn({() in 444}), 444)
+  // This too:
+  expectEqual(callFunctionWithReturn({() in true}), true)
+  // But this does not (probably a quirk of expectTrue())
+  // expectTrue(callFunctionWithReturn({() in true}))
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithReturn<F, T> where F == () -> CxxClass, T == CxxClass") {
+  let c: CxxClass = callFunctionWithReturn({() in CxxClass(x: 42)})
+  expectEqual(c.x, 42)
+
+  let d: CxxClass = callFunctionWithReturn({() in c})
+  expectEqual(d.x, 42)
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithPassthrough<F, T> where F == (T) -> T, T == Int") {
+  expectEqual(callFunctionWithPassthrough({(x: Int) in x}, 42), 42)
+  expectEqual(callFunctionWithPassthrough({(x: Int) in 24}, 42), 24)
+  expectEqual(callFunctionWithPassthrough({(x: Int) in x + 42}, 42), 84)
+}
+
+FunctionTemplateClosuresTestSuite.test("indirectlyCallFunction<T> where T == () -> ()") {
+  var value = 42
+
+  indirectlyCallFunction({() in value = 111});
+  expectEqual(value, 111)
+
+  indirectlyCallFunctionTemplate({() in value = 222});
+  expectEqual(value, 222)
+}
+
+FunctionTemplateClosuresTestSuite.test("indirectlyCallFunction<T> where T == () -> ()") {
+  var value: CInt = 0
+
+  indirectlyCallFunctionWith42({(x: CInt) in value = x});
+  expectEqual(value, 42)
+
+  indirectlyCallFunctionWithCxxClass24({(c: CxxClass) in value = c.x});
+  expectEqual(value, 24)
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithReturn<F, T> where F == void (^)(int), T == CInt") {
+  var value: CInt = 0
+
+  value = callFunctionWithReturn(blockReturns111!)
+  expectEqual(value, 111)
+
+  value = callFunctionWithReturn(nonNullBlockReturns222)
+  expectEqual(value, 222)
+
+  getConstantIntBlock(333, {cb in value = callFunctionWithReturn(cb) })
+  expectEqual(value, 333)
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithPassthrough<F, T> where F == int (^)(int), T == CInt") {
+  expectEqual(callFunctionWithPassthrough(blockTripleInt!, 7), 21)
+  expectEqual(callFunctionWithPassthrough(nonNullBlockTripleInt, 8), 24)
+  expectEqual(getMultiplyIntBlock(9, {cb in callFunctionWithPassthrough(cb, 3)}), 27)
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithReturn<T, B> where T == C function ptr, B == CInt") {
+  var value: CInt = 0
+
+  value = callFunctionWithReturn(get42)
+  expectEqual(value, 42)
+
+  value = callFunctionWithReturn(functionPtrGet42!)
+  expectEqual(value, 42)
+
+  value = callFunctionWithReturn(nonNullFunctionPtrGet42)
+  expectEqual(value, 42)
+}
+
+FunctionTemplateClosuresTestSuite.test("callFunctionWithPassthrough<F, T> where C function ptr, T == CInt") {
+  expectEqual(callFunctionWithPassthrough(tripleInt, 4), 12)
+  expectEqual(callFunctionWithPassthrough(functionPtrTripleInt!, 5), 15)
+  expectEqual(callFunctionWithPassthrough(nonNullFunctionPtrTripleInt, 6), 18)
+}
+
+runAllTests()
diff --git a/test/Interop/Cxx/templates/function-template-module-interface.swift b/test/Interop/Cxx/templates/function-template-module-interface.swift
index 34f92bead4074..38cc7f1906630 100644
--- a/test/Interop/Cxx/templates/function-template-module-interface.swift
+++ b/test/Interop/Cxx/templates/function-template-module-interface.swift
@@ -20,7 +20,10 @@
 
 // CHECK: func lvalueReference<T>(_ ref: inout T)
 // CHECK: func constLvalueReference<T>(_: T)
-// CHECK: func PointerTemplateParameter<T>(_: UnsafeMutablePointer<T>)
+
+// CHECK: func pointerTemplateParameter<T>(_ t: UnsafeMutablePointer<T>!) -> Bool
+// CHECK: func pointerTemplateParameterNonnull<T>(_ t: UnsafeMutablePointer<T>) -> Bool
+// CHECK: func pointerTemplateParameterNullable<T>(_ t: UnsafeMutablePointer<T>?) -> Bool
 
 // CHECK: enum Orbiters {
 // CHECK:   static func galileo<T>(_: T)
diff --git a/test/Interop/Cxx/templates/function-template-typechecker-errors.swift b/test/Interop/Cxx/templates/function-template-typechecker-errors.swift
index 8ab44a4af8451..329fbe40b713c 100644
--- a/test/Interop/Cxx/templates/function-template-typechecker-errors.swift
+++ b/test/Interop/Cxx/templates/function-template-typechecker-errors.swift
@@ -1,4 +1,4 @@
-// RUN: not %target-typecheck-verify-swift -I %S/Inputs -enable-experimental-cxx-interop 2>&1 | %FileCheck %s
+// RUN: not %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -enable-experimental-cxx-interop 2>&1 | %FileCheck %s
 
 // README: If you just added support for protocol composition to the
 // ClangTypeConverter, please update this test to use a different type that we
@@ -25,12 +25,12 @@ public protocol A { }
 public protocol B { }
 public protocol C { }
 
-// CHECK: error: unexpected error produced: could not generate C++ types from the generic Swift types provided; the following Swift type(s) provided to 'passThrough' could not be converted: any A & B
+// CHECK: function-templates.h{{.*}}: error: diagnostic produced elsewhere: could not generate C++ types from the generic Swift types provided; the following Swift type(s) provided to 'passThrough' could not be converted: any A & B
 public func caller1(x: A & B) -> A & B {
   return passThrough(x)
 }
 
-// CHECK: error: unexpected error produced: could not generate C++ types from the generic Swift types provided; the following Swift type(s) provided to 'addMixedTypeParams' could not be converted: any A & B, any A & C
+// CHECK: function-templates.h{{.*}}: error: diagnostic produced elsewhere: could not generate C++ types from the generic Swift types provided; the following Swift type(s) provided to 'addMixedTypeParams' could not be converted: any A & B, any A & C
 public func caller2(x: A & B, y: A & C) -> A & B {
   return addMixedTypeParams(x, y)
 }
diff --git a/test/Interop/Cxx/templates/function-template.swift b/test/Interop/Cxx/templates/function-template.swift
index d718040390e8d..e78a4d2aabc22 100644
--- a/test/Interop/Cxx/templates/function-template.swift
+++ b/test/Interop/Cxx/templates/function-template.swift
@@ -39,6 +39,26 @@ FunctionTemplateTestSuite.test("constLvalueReferenceToBool<T> where T == Bool")
   expectFalse(constLvalueReferenceToBool(false))
 }
 
+var nilPtr: UnsafeMutablePointer<CInt>? = nil
+var nilPtrIOU: UnsafeMutablePointer<CInt>! = nil
+var nonNilPtr: UnsafeMutablePointer<CInt> = .init(bitPattern: 123)!
+
+FunctionTemplateTestSuite.test("pointerTemplateParameter<T>") {
+  expectFalse(pointerTemplateParameter(nilPtr))
+  expectFalse(pointerTemplateParameter(nilPtrIOU))
+  expectTrue(pointerTemplateParameter(nonNilPtr))
+}
+
+FunctionTemplateTestSuite.test("pointerTemplateParameterNonnull<T>") {
+  expectTrue(pointerTemplateParameterNonnull(nonNilPtr))
+}
+
+FunctionTemplateTestSuite.test("pointerTemplateParameterNullable<T>") {
+  expectFalse(pointerTemplateParameterNullable(nilPtr))
+  expectFalse(pointerTemplateParameterNullable(nilPtrIOU))
+  expectTrue(pointerTemplateParameterNullable(nonNilPtr))
+}
+
 // TODO: Generics, Any, and Protocols should be tested here but need to be
 // better supported in ClangTypeConverter first.
 
diff --git a/test/Interop/Cxx/templates/mangling-irgen.swift b/test/Interop/Cxx/templates/mangling-irgen.swift
index 3a5f1e8f349ef..528a4d13d61d8 100644
--- a/test/Interop/Cxx/templates/mangling-irgen.swift
+++ b/test/Interop/Cxx/templates/mangling-irgen.swift
@@ -4,12 +4,12 @@ import Mangling
 
 public func receiveInstantiation(_ i: inout WrappedMagicBool) {}
 
-// CHECK: define {{(protected |dllexport )?}}swiftcc void @"$s4main20receiveInstantiationyySo0025MagicWrapperCBool_lsFCfibVzF"(ptr nocapture dereferenceable(1) %0)
+// CHECK: define {{(protected |dllexport )?}}swiftcc void @"$s4main20receiveInstantiationyySo0025MagicWrapperCBool_lsFCfibVzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable(1) %0)
 
 public func receiveInstantiation(_ i: inout WrappedMagicInt) {}
 
 // Don't forget to update manglings.txt when changing s4main20receiveInstantiationyySo34__CxxTemplateInst12MagicWrapperIiEVzF
-// CHECK: define {{(protected |dllexport )?}}swiftcc void @"$s4main20receiveInstantiationyySo0024MagicWrapperCInt_npAIefbVzF"(ptr nocapture dereferenceable(1) %0)
+// CHECK: define {{(protected |dllexport )?}}swiftcc void @"$s4main20receiveInstantiationyySo0024MagicWrapperCInt_npAIefbVzF"(ptr {{(nocapture|captures\(none\))}} dereferenceable(1) %0)
 
 public func returnInstantiation() -> WrappedMagicInt {
   return WrappedMagicInt()
diff --git a/test/Interop/Cxx/templates/many-specializations.swift b/test/Interop/Cxx/templates/many-specializations.swift
index a1ae3f5f43a75..cc6f6820a15b5 100644
--- a/test/Interop/Cxx/templates/many-specializations.swift
+++ b/test/Interop/Cxx/templates/many-specializations.swift
@@ -5,4 +5,4 @@
 // CHECK-NEXT: struct TemplateStruct<T> {
 // CHECK-NEXT: }
 
-// CHECK-NOT: typealias
+// CHECK: typealias T1000
diff --git a/test/Interop/Cxx/templates/static-cast-typecheck.swift b/test/Interop/Cxx/templates/static-cast-typecheck.swift
new file mode 100644
index 0000000000000..fa6d4537c1735
--- /dev/null
+++ b/test/Interop/Cxx/templates/static-cast-typecheck.swift
@@ -0,0 +1,44 @@
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -typecheck -verify -suppress-remarks -suppress-notes \
+// RUN:     -cxx-interoperability-mode=default \
+// RUN:     -I %t%{fs-sep}Inputs %t%{fs-sep}main.swift \
+// RUN:     -verify-additional-file %t%{fs-sep}Inputs%{fs-sep}header.h
+
+//--- Inputs/module.modulemap
+module CxxHeader {
+    header "header.h"
+    requires cplusplus
+}
+
+//--- Inputs/header.h
+#pragma once
+
+// TODO: the following diagnostics should be moved to main.swift at the call site
+//       that triggers the instantiation
+// expected-error@+4 {{could not substitute parameters for C++ function template 'cxxCast': BaseT, UnrelatedT}}
+// expected-error@+3 {{could not substitute parameters for C++ function template 'cxxCast': BaseT, SubClassT}}
+// expected-error@+2 {{could not substitute parameters for C++ function template 'cxxCast': BaseT, SubProtectedT}}
+// expected-error@+1 {{could not substitute parameters for C++ function template 'cxxCast': BaseT, SubPrivateT}}
+template <class O, class I> O cxxCast(I i) { return static_cast<O>(i); }
+// expected-error@-1 {{cannot cast 'const SubPrivateT' to its private base class 'const BaseT'}}
+// expected-error@-2 {{cannot cast 'const SubProtectedT' to its protected base class 'const BaseT'}}
+// expected-error@-3 {{cannot cast 'const SubClassT' to its private base class 'const BaseT'}}
+// expected-error@-4 {{no matching conversion for static_cast from 'UnrelatedT' to 'BaseT'}}
+
+struct BaseT { };
+
+struct SubT          : BaseT            { }; // publicly inherit from BaseT
+struct SubPrivateT   : private BaseT    { }; // privately inherit from BaseT
+struct SubProtectedT : protected BaseT  { }; // privately inherit from BaseT
+class  SubClassT     : BaseT            { }; // privately inherit from BaseT
+struct UnrelatedT                       { }; // does not inherit from BaseT
+
+
+//--- main.swift
+import CxxHeader
+
+let _: BaseT = cxxCast(SubT())          // valid:   upcast to public base
+let _: BaseT = cxxCast(SubPrivateT())   // invalid: upcast to non-public base
+let _: BaseT = cxxCast(SubProtectedT()) // invalid: upcast to non-public base
+let _: BaseT = cxxCast(SubClassT())     // invalid: upcast to non-public base
+let _: BaseT = cxxCast(UnrelatedT())    // invalid: cast to unrelated type
diff --git a/test/Interop/Cxx/templates/swift-class-template-specialization-module-xref.swift b/test/Interop/Cxx/templates/swift-class-template-specialization-module-xref.cpp
similarity index 100%
rename from test/Interop/Cxx/templates/swift-class-template-specialization-module-xref.swift
rename to test/Interop/Cxx/templates/swift-class-template-specialization-module-xref.cpp
diff --git a/test/Interop/Cxx/templates/template-instantiation-irgen.swift b/test/Interop/Cxx/templates/template-instantiation-irgen.swift
index 834a7e11d747c..fe334652aa1ec 100644
--- a/test/Interop/Cxx/templates/template-instantiation-irgen.swift
+++ b/test/Interop/Cxx/templates/template-instantiation-irgen.swift
@@ -1,4 +1,18 @@
+// This regression test was originally written because the Swift compiler would
+// crash when it tried to instantiate C++ function templates with various types.
+// In particular, instantiating them with Swift types was problematic.
+//
+// Aside from validating that we can successfully instantiate function templates
+// with basic primitive types (e.g., Bool, Int32) and imported C/ObjC/C++ types,
+// this regression test aims to document the current status of C++ function
+// template instantiation.
+//
+// With the following, we check the happy path, that we _can_ successfully emit
+// SIL for certain template instantiations:
 // RUN: %target-swift-emit-ir %s -I %S/Inputs -cxx-interoperability-mode=default -disable-availability-checking | %FileCheck %s
+//
+// Some instantiations still cause Swift compiler crashes. These are documented
+// with "FIXME" comments.
 
 import FunctionTemplates
 
@@ -32,8 +46,8 @@ func takesPtrToStruct(x: UnsafePointer<PlainStruct>) { takesValue(x) }
 func takesPtrToClass(x: UnsafePointer<CxxClass>) { takesValue(x) }
 // CHECK: define {{.*}} void @{{.*}}takesPtrToClass{{.*}}
 
-// TODO: this does not work because this round-trips to UnsafePointer<FRT?>
-// func takesPtrToFRT(x: UnsafePointer<FRT>) { takesValue(x) }
+func takesPtrToFRT(x: UnsafePointer<FRT>) { takesValue(x) }
+// CHECK: define {{.*}} void @{{.*}}takesPtrToFRT{{.*}}
 
 func takesMutPtrToStruct(x: UnsafeMutablePointer<PlainStruct>) { takesValue(x) }
 // CHECK: define {{.*}} void @{{.*}}takesMutPtrToStruct{{.*}}
@@ -41,12 +55,42 @@ func takesMutPtrToStruct(x: UnsafeMutablePointer<PlainStruct>) { takesValue(x) }
 func takesMutPtrToClass(x: UnsafeMutablePointer<CxxClass>) { takesValue(x) }
 // CHECK: define {{.*}} void @{{.*}}takesMutPtrToClass{{.*}}
 
-// TODO: this does not work because this round-trips to UnsafeMutablePointer<FRT?>
-// func takesMutPtrToFRT(x: UnsafeMutablePointer<FRT>) { takesValue(x) }
+func takesMutPtrToFRT(x: UnsafeMutablePointer<FRT>) { takesValue(x) }
+// CHECK: define {{.*}} void @{{.*}}takesMutPtrToFRT{{.*}}
 
-// TODO: optional pointers are not yet supported but they should be
-// func takesCPtr() { takesValue(intPtr) }
-func takesCPtr() { let swiftPtr = intPtr!; takesValue(swiftPtr) }
+func takesCPtr() {
+  takesValue(intPtr)
 
-// TODO: function pointers are not yet supported but they should be
-// func takesCFnPtr() { takesValue(functionPtr) }
+  // It's fine if we dereference it, though
+  takesValue(intPtr!)
+}
+
+func takesCFnPtr() {
+  takesValue(get42) // function symbol
+  // FIXME: optional pointers are not yet supported but they should be; this crashes
+  // takesValue(functionPtrGet42)
+  takesValue(functionPtrGet42!) // dereferenced nullable function pointer
+  takesValue(nonNullFunctionPtrGet42) // non-null function symbol
+}
+
+func takesRecursively() { takesValue(takesRecursively) }
+func takesRecursiveClosure() { takesValue({() in takesRecursiveClosure()}) }
+func takesSwiftClosure() { takesValue({() in ()}) }
+func takesTakesTrue() { takesValue(takesTrue) }
+
+func takesSwiftClosureReturningBool() { takesValue({() -> Bool in true}) }
+func takesSwiftClosureTakingBool() { takesValue({(x: Bool) in ()}) }
+func takesTakesBool() { takesValue(takesBool) }
+
+func takesSwiftClosureReturningPlainStruct() { takesValue({() -> PlainStruct in PlainStruct(x: 42)}) }
+func takesSwiftClosureTakingPlainStruct() { takesValue({(x: PlainStruct) in takesValue(x)}) }
+func takesTakesPlainStruct() { takesValue(takesPlainStruct) }
+
+func takesSwiftClosureReturningCxxClass() { takesValue({() -> CxxClass in CxxClass(x: 42)}) }
+func takesSwiftClosureTakingCxxClass() { takesValue({(x: CxxClass) in takesValue(x)}) }
+func takesTakesCxxClass() { takesValue(takesCxxClass) }
+
+func takesSwiftClosureReturningFRT() { takesValue({() -> FRT in FRT()}) }
+func takesSwiftClosureTakingFRT() { takesValue({(x: FRT) in takesValue(x)}) }
+
+func takesTakesFRT() { takesValue(takesFRT) }
diff --git a/test/Interop/Cxx/templates/uninstantiatable-special-members-irgen.swift b/test/Interop/Cxx/templates/uninstantiatable-special-members-irgen.swift
new file mode 100644
index 0000000000000..8d279a8c373dc
--- /dev/null
+++ b/test/Interop/Cxx/templates/uninstantiatable-special-members-irgen.swift
@@ -0,0 +1,8 @@
+// RUN: %target-swift-emit-irgen %s -cxx-interoperability-mode=default -I %S/Inputs | %FileCheck %s
+
+import UninstantiatableSpecialMembers
+
+let nonCopyableValue = NonCopyableInst(123)
+let nonCopyableDerived = DerivedNonCopyableInst(567)
+
+// CHECK-NOT: scaryPoison
diff --git a/test/Interop/Cxx/templates/uninstantiatable-special-members-module-interface.swift b/test/Interop/Cxx/templates/uninstantiatable-special-members-module-interface.swift
new file mode 100644
index 0000000000000..b888676068828
--- /dev/null
+++ b/test/Interop/Cxx/templates/uninstantiatable-special-members-module-interface.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=UninstantiatableSpecialMembers -I %S/Inputs -source-filename=x -cxx-interoperability-mode=upcoming-swift | %FileCheck %s
+
+// CHECK: struct HasUninstantiatableCopyConstructor<CInt> {
+// CHECK: }
+// CHECK: typealias NonCopyableInst = HasUninstantiatableCopyConstructor<CInt>
+
+// CHECK: struct DerivedUninstantiatableCopyConstructor<CInt> {
+// CHECK: }
+// CHECK: typealias DerivedNonCopyableInst = DerivedUninstantiatableCopyConstructor<CInt>
diff --git a/test/Interop/Cxx/templates/uninstantiatable-special-members-typechecker.swift b/test/Interop/Cxx/templates/uninstantiatable-special-members-typechecker.swift
new file mode 100644
index 0000000000000..c037a5b404a88
--- /dev/null
+++ b/test/Interop/Cxx/templates/uninstantiatable-special-members-typechecker.swift
@@ -0,0 +1,9 @@
+// RUN: %target-typecheck-verify-swift -cxx-interoperability-mode=default -I %S/Inputs
+
+import UninstantiatableSpecialMembers
+
+let nonCopyableValue = NonCopyableInst(123)
+let copy1 = copy nonCopyableValue // expected-error {{'copy' cannot be applied to noncopyable types}}
+
+let nonCopyableDerived = DerivedNonCopyableInst(567)
+let copy2 = copy nonCopyableDerived // expected-error {{'copy' cannot be applied to noncopyable types}}
diff --git a/test/Interop/Cxx/templates/variable-template-typechecker.swift b/test/Interop/Cxx/templates/variable-template-typechecker.swift
new file mode 100644
index 0000000000000..3e628d34b1873
--- /dev/null
+++ b/test/Interop/Cxx/templates/variable-template-typechecker.swift
@@ -0,0 +1,5 @@
+// RUN: %target-typecheck-verify-swift -cxx-interoperability-mode=default -I %S/Inputs
+
+import VariableTemplate
+
+let _: CInt = template_gcd // expected-error {{cannot find 'template_gcd' in scope}}
diff --git a/test/Interop/Cxx/union/anonymous-union-const-member.swift b/test/Interop/Cxx/union/anonymous-union-const-member.swift
new file mode 100644
index 0000000000000..4d2a3d279c7a3
--- /dev/null
+++ b/test/Interop/Cxx/union/anonymous-union-const-member.swift
@@ -0,0 +1,32 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend   -typecheck -verify -I %t/Inputs %t/main.swift
+// RUN: %target-swiftxx-frontend -typecheck -verify -I %t/Inputs %t/main.swift
+
+// Import an anonymous union with const and non-const members. Constant members
+// appear within Foo as clang::IndirectFieldDecl and should be imported in Swift
+// as computed properties with private setters (since it is possible to change
+// the values of const members in C/C++).
+
+//--- Inputs/module.modulemap
+module CxxModule { header "header.h" }
+
+//--- Inputs/header.h
+#pragma once
+
+struct Foo {
+  union {
+    const int constant;
+    int variable;
+  };
+};
+
+//--- main.swift
+import CxxModule
+
+func fooer(_ f: inout Foo) {
+  let _ = f.variable
+  let _ = f.constant
+  f.variable = 42
+  f.constant = 42 // expected-error {{setter is inaccessible}}
+}
diff --git a/test/Interop/Cxx/value-witness-table/custom-destructors-typechecker-trivial-windows-abi.swift b/test/Interop/Cxx/value-witness-table/custom-destructors-typechecker-trivial-windows-abi.swift
index 8d555ad22672e..12e8bc1e2361f 100644
--- a/test/Interop/Cxx/value-witness-table/custom-destructors-typechecker-trivial-windows-abi.swift
+++ b/test/Interop/Cxx/value-witness-table/custom-destructors-typechecker-trivial-windows-abi.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -I %S/Inputs -enable-experimental-cxx-interop -Xcc -DWIN_TRIVIAL
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs -enable-experimental-cxx-interop -Xcc -DWIN_TRIVIAL
 
 // REQUIRES: OS=windows-msvc
 
diff --git a/test/Interop/Cxx/value-witness-table/custom-destructors-virtual-irgen.swift b/test/Interop/Cxx/value-witness-table/custom-destructors-virtual-irgen.swift
index 5056ade88b1b7..db1c33bf9e151 100644
--- a/test/Interop/Cxx/value-witness-table/custom-destructors-virtual-irgen.swift
+++ b/test/Interop/Cxx/value-witness-table/custom-destructors-virtual-irgen.swift
@@ -1,8 +1,4 @@
-// With RTTI some of the objects with virtual bases / destructors in this test
-// will cause linker errors because of undefined vtables.
-// FIXME: Once we can link with libc++ we can start using RTTI.
-//
-// RUN: %target-swift-frontend -enable-experimental-cxx-interop -I %S/Inputs %s -emit-ir -Xcc -fno-rtti | %FileCheck %s
+// RUN: %target-swift-frontend -cxx-interoperability-mode=default -I %S/Inputs %s -emit-ir | %FileCheck %s
 
 import CustomDestructor
 
diff --git a/test/Interop/Cxx/value-witness-table/custom-destructors-virtual.swift b/test/Interop/Cxx/value-witness-table/custom-destructors-virtual.swift
index 8ec9bd748fe92..b79269fb864f6 100644
--- a/test/Interop/Cxx/value-witness-table/custom-destructors-virtual.swift
+++ b/test/Interop/Cxx/value-witness-table/custom-destructors-virtual.swift
@@ -1,9 +1,5 @@
-// With RTTI some of the objects with virtual bases / destructors in this test
-// will cause linker errors because of undefined vtables.
-// FIXME: Once we can link with libc++ we can start using RTTI.
-// 
-// RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -Xcc -fno-rtti)
-// RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -Xcc -fno-rtti -O)
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=default)
+// RUN: %target-run-simple-swift(-I %S/Inputs -cxx-interoperability-mode=default -O)
 //
 // REQUIRES: executable_test
 
diff --git a/test/Interop/CxxToSwiftToCxx/bridge-bridging-header-to-cxx.swift b/test/Interop/CxxToSwiftToCxx/bridge-bridging-header-to-cxx.swift
new file mode 100644
index 0000000000000..edc9961bd7334
--- /dev/null
+++ b/test/Interop/CxxToSwiftToCxx/bridge-bridging-header-to-cxx.swift
@@ -0,0 +1,26 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -typecheck %t/use-cxx-types.swift -typecheck -module-name UseCxx -emit-clang-header-path %t/UseCxx.h -I %t -enable-experimental-cxx-interop -clang-header-expose-decls=all-public -import-objc-header %t/header.h
+
+// RUN: %target-interop-build-clangxx -std=c++20 -c %t/use-swift-cxx-types.cpp -I %t -o %t/swift-cxx-execution.o -g
+// RUN: %target-interop-build-swift %t/use-cxx-types.swift -o %t/swift-cxx-execution -Xlinker %t/swift-cxx-execution.o -module-name UseCxx -Xfrontend -entry-point-function-name -Xfrontend swiftMain -I %t -g -import-objc-header %t/header.h
+
+//--- header.h
+struct CxxTy {
+    int field;
+};
+
+//--- use-cxx-types.swift
+public func foo() -> CxxTy {
+    CxxTy()
+}
+
+//--- use-swift-cxx-types.cpp
+
+#include "header.h"
+#include "UseCxx.h"
+
+int main() {
+    auto obj = UseCxx::foo();
+}
diff --git a/test/Interop/CxxToSwiftToCxx/bridge-cxx-struct-back-to-cxx.swift b/test/Interop/CxxToSwiftToCxx/bridge-cxx-struct-back-to-cxx.swift
index d460c4dc4711e..cae37b20351fb 100644
--- a/test/Interop/CxxToSwiftToCxx/bridge-cxx-struct-back-to-cxx.swift
+++ b/test/Interop/CxxToSwiftToCxx/bridge-cxx-struct-back-to-cxx.swift
@@ -200,10 +200,7 @@ public struct Strct {
 // CHECK:  ns::ImmortalTemplate<int> *_Nonnull retImmortalTemplate() noexcept SWIFT_SYMBOL({{.*}}) SWIFT_WARN_UNUSED_RESULT {
 // CHECK-NEXT: return UseCxxTy::_impl::$s8UseCxxTy19retImmortalTemplateSo2nsO0028ImmortalTemplateCInt_jBAGgnbVyF();
 // CHECK-NEXT: }
-
-// CHECK: } // end namespace
 // CHECK-EMPTY:
-// CHECK-NEXT: namespace swift SWIFT_PRIVATE_ATTR {
 // CHECK-NEXT: namespace _impl {
 // CHECK-EMPTY:
 // CHECK-NEXT: // Type metadata accessor for NonTrivialTemplateInt
@@ -212,6 +209,9 @@ public struct Strct {
 // CHECK-EMPTY:
 // CHECK-NEXT: } // namespace _impl
 // CHECK-EMPTY:
+// CHECK-NEXT: } // end namespace
+// CHECK-EMPTY:
+// CHECK-NEXT: namespace swift SWIFT_PRIVATE_ATTR {
 // CHECK-NEXT: #pragma clang diagnostic push
 // CHECK-NEXT: #pragma clang diagnostic ignored "-Wc++17-extensions"
 // CHECK-NEXT: template<>
@@ -219,7 +219,7 @@ public struct Strct {
 // CHECK-NEXT: template<>
 // CHECK-NEXT: struct TypeMetadataTrait<ns::NonTrivialTemplateInt> {
 // CHECK-NEXT:   static SWIFT_INLINE_PRIVATE_HELPER void * _Nonnull getTypeMetadata() {
-// CHECK-NEXT:     return _impl::$sSo2nsO0030NonTrivialTemplateCInt_hHAFhrbVMa(0)._0;
+// CHECK-NEXT:     return UseCxxTy::_impl::$sSo2nsO0030NonTrivialTemplateCInt_hHAFhrbVMa(0)._0;
 // CHECK-NEXT:   }
 // CHECK-NEXT: };
 // CHECK-NEXT: namespace _impl{
@@ -240,9 +240,6 @@ public struct Strct {
 // CHECK-NEXT: return result;
 // CHECK-NEXT: }
 // CHECK-EMPTY:
-// CHECK-NEXT: } // end namespace
-// CHECK-EMPTY:
-// CHECK-NEXT: namespace swift SWIFT_PRIVATE_ATTR {
 // CHECK-NEXT: namespace _impl {
 // CHECK-EMPTY:
 // CHECK-NEXT: // Type metadata accessor for NonTrivialTemplateTrivial
@@ -251,6 +248,9 @@ public struct Strct {
 // CHECK-EMPTY:
 // CHECK-NEXT: } // namespace _impl
 // CHECK-EMPTY:
+// CHECK-NEXT: } // end namespace
+// CHECK-EMPTY:
+// CHECK-NEXT: namespace swift SWIFT_PRIVATE_ATTR {
 // CHECK-NEXT: #pragma clang diagnostic push
 // CHECK-NEXT: #pragma clang diagnostic ignored "-Wc++17-extensions"
 // CHECK-NEXT: template<>
@@ -258,7 +258,7 @@ public struct Strct {
 // CHECK-NEXT: template<>
 // CHECK-NEXT: struct TypeMetadataTrait<ns::NonTrivialTemplateTrivial> {
 // CHECK-NEXT:   static SWIFT_INLINE_PRIVATE_HELPER void * _Nonnull getTypeMetadata() {
-// CHECK-NEXT:     return _impl::$sSo2nsO0042NonTrivialTemplatensTrivialinNS_HlGFlenawcVMa(0)._0;
+// CHECK-NEXT:     return UseCxxTy::_impl::$sSo2nsO0042NonTrivialTemplatensTrivialinNS_HlGFlenawcVMa(0)._0;
 // CHECK-NEXT:   }
 // CHECK-NEXT: };
 // CHECK-NEXT: namespace _impl{
diff --git a/test/Interop/CxxToSwiftToCxx/nested-cxx-class-back-to-swift.swift b/test/Interop/CxxToSwiftToCxx/nested-cxx-class-back-to-swift.swift
new file mode 100644
index 0000000000000..446f211f290d3
--- /dev/null
+++ b/test/Interop/CxxToSwiftToCxx/nested-cxx-class-back-to-swift.swift
@@ -0,0 +1,27 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend %t/use-cxx-types.swift -module-name UseCxxTy -typecheck -verify -emit-clang-header-path %t/UseCxxTy.h -I %t -enable-experimental-cxx-interop -clang-header-expose-decls=all-public -disable-availability-checking
+// RUN: cat %t/header.h >> %t/full-header.h
+// RUN: cat %t/UseCxxTy.h >> %t/full-header.h
+// RUN: %target-interop-build-clangxx -std=c++20 -c -xc++-header %t/full-header.h -o %t/o.o
+
+//--- header.h
+
+struct Cell { class Visitor {}; };
+
+//--- module.modulemap
+module CxxTest {
+    header "header.h"
+    requires cplusplus
+}
+
+//--- use-cxx-types.swift
+import CxxTest
+
+public extension Cell.Visitor {
+    func visit() {}
+}
+
+public func f() -> [Cell.Visitor] {
+}
diff --git a/test/Interop/CxxToSwiftToCxx/references-correctly-mangled-execution.cpp b/test/Interop/CxxToSwiftToCxx/references-correctly-mangled-execution.cpp
new file mode 100644
index 0000000000000..e60fdd39a3864
--- /dev/null
+++ b/test/Interop/CxxToSwiftToCxx/references-correctly-mangled-execution.cpp
@@ -0,0 +1,53 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -typecheck %t/use-cxx-types.swift -typecheck -module-name UseCxx -emit-clang-header-path %t/UseCxx.h -I %t -enable-experimental-cxx-interop -clang-header-expose-decls=all-public
+
+// RUN: %target-interop-build-clangxx -std=c++20 -c %t/use-swift-cxx-types.cpp -I %t -o %t/swift-cxx-execution.o -g
+// RUN: %target-interop-build-swift %t/use-cxx-types.swift -o %t/swift-cxx-execution -Xlinker %t/swift-cxx-execution.o -module-name UseCxx -Xfrontend -entry-point-function-name -Xfrontend swiftMain -I %t -g
+
+// RUN: %target-codesign %t/swift-cxx-execution
+// RUN: %target-run %t/swift-cxx-execution
+
+// REQUIRES: executable_test
+
+//--- header.h
+#include <functional>
+namespace my_cpp {
+struct First {
+  double value;
+};
+struct Second {
+  bool value;
+};
+
+using First_cb = std::function<void(const First &)>;
+using Second_cb = std::function<void(const Second &)>;
+} // namespace my_cpp
+
+//--- module.modulemap
+module CxxTest {
+    header "header.h"
+    requires cplusplus
+}
+
+//--- use-cxx-types.swift
+import CxxStdlib
+import CxxTest
+
+public func
+hello(first : my_cpp.First_cb /* std::function */,
+      second : my_cpp.Second_cb /* std::function */) {
+  first.callAsFunction(my_cpp.First(value : 3.14))
+      second.callAsFunction(my_cpp.Second(value : true))
+}
+
+//--- use-swift-cxx-types.cpp
+
+#include "header.h"
+#include "UseCxx.h"
+#include <assert.h>
+
+int main() {
+  UseCxx::hello([](const my_cpp::First &) {}, [](const my_cpp::Second &) {});
+}
\ No newline at end of file
diff --git a/test/Interop/CxxToSwiftToCxx/simd-bridge-cxx-struct-back-to-cxx.swift b/test/Interop/CxxToSwiftToCxx/simd-bridge-cxx-struct-back-to-cxx.swift
index e32bc9ef122e7..fa568c72f0f1b 100644
--- a/test/Interop/CxxToSwiftToCxx/simd-bridge-cxx-struct-back-to-cxx.swift
+++ b/test/Interop/CxxToSwiftToCxx/simd-bridge-cxx-struct-back-to-cxx.swift
@@ -43,5 +43,14 @@ public func passStruct(_ x : Struct) {
 }
 
 // CHECK: class SWIFT_SYMBOL("s:8UseCxxTy6StructV") Struct final {
-// CHECK-NOT: init(
-// CHECK:  // Unavailable in C++: Swift global function 'passStruct(_:)'
+
+// CHECK: SWIFT_INLINE_THUNK void passStruct(const Struct& x) noexcept SWIFT_SYMBOL("s:8UseCxxTy10passStructyyAA0E0VF") {
+// CHECK-NEXT:   UseCxxTy::_impl::$s8UseCxxTy10passStructyyAA0E0VF(UseCxxTy::_impl::swift_interop_passDirect_UseCxxTy_swift_float4_0_16_swift_float4_16_32_swift_float4_32_48_swift_float4_48_64(UseCxxTy::_impl::_impl_Struct::getOpaquePointer(x)));
+// CHECK-NEXT:}
+
+// CHECK:  SWIFT_INLINE_THUNK Struct Struct::init() {
+// CHECK-NEXT:  return UseCxxTy::_impl::_impl_Struct::returnNewValue([&](char * _Nonnull result) SWIFT_INLINE_THUNK_ATTRIBUTES {
+// CHECK-NEXT:    UseCxxTy::_impl::swift_interop_returnDirect_UseCxxTy_swift_float4_0_16_swift_float4_16_32_swift_float4_32_48_swift_float4_48_64(result, UseCxxTy::_impl::$s8UseCxxTy6StructVACycfC());
+// CHECK-NEXT:  });
+// CHECK-NEXT:  }
+
diff --git a/test/Interop/CxxToSwiftToCxx/span/span-execution.cpp b/test/Interop/CxxToSwiftToCxx/span/span-execution.cpp
index 06864db50f3c3..839e89ba38eb6 100644
--- a/test/Interop/CxxToSwiftToCxx/span/span-execution.cpp
+++ b/test/Interop/CxxToSwiftToCxx/span/span-execution.cpp
@@ -9,11 +9,10 @@
 // RUN: %target-codesign %t/swift-cxx-execution
 // RUN: %target-run %t/swift-cxx-execution | %FileCheck %s
 
-// FIXME swift-ci linux tests do not support std::span
-// UNSUPPORTED: OS=linux-gnu
-
 // REQUIRES: executable_test
 
+// REQUIRES: OS=macosx || rdar-161999258
+
 //--- header.h
 #include <string>
 #include <span>
diff --git a/test/Interop/ObjC/lit.local.cfg b/test/Interop/ObjC/lit.local.cfg
new file mode 100644
index 0000000000000..dc6afccf21d22
--- /dev/null
+++ b/test/Interop/ObjC/lit.local.cfg
@@ -0,0 +1,2 @@
+if 'objc_interop' not in config.available_features:
+    config.unsupported = True
diff --git a/test/Interop/ObjC/swiftify-import/Inputs/module.modulemap b/test/Interop/ObjC/swiftify-import/Inputs/module.modulemap
new file mode 100644
index 0000000000000..8ed2a884eb43c
--- /dev/null
+++ b/test/Interop/ObjC/swiftify-import/Inputs/module.modulemap
@@ -0,0 +1,4 @@
+module NoSwiftifyClang {
+    header "objc-no-swiftify.h"
+    export *
+}
diff --git a/test/Interop/ObjC/swiftify-import/Inputs/objc-no-swiftify.h b/test/Interop/ObjC/swiftify-import/Inputs/objc-no-swiftify.h
new file mode 100644
index 0000000000000..4b01f0e94f4f7
--- /dev/null
+++ b/test/Interop/ObjC/swiftify-import/Inputs/objc-no-swiftify.h
@@ -0,0 +1,9 @@
+#define __counted_by(x) __attribute__((__counted_by__(x)))
+
+@interface SomeClass
+- (int)numberOfSegments;
+@end
+
+void autoreleaseParam(SomeClass * __autoreleasing * __counted_by(len) p, int len); // expected-note{{declared here}}
+
+SomeClass * __autoreleasing * __counted_by(len) autoreleaseReturn(int len);
diff --git a/test/Interop/ObjC/swiftify-import/counted-by-in-class.swift b/test/Interop/ObjC/swiftify-import/counted-by-in-class.swift
index 5cfa11553be9e..a0a3447a6abf8 100644
--- a/test/Interop/ObjC/swiftify-import/counted-by-in-class.swift
+++ b/test/Interop/ObjC/swiftify-import/counted-by-in-class.swift
@@ -5,8 +5,6 @@
 // RUN: %target-swift-ide-test -plugin-path %swift-plugin-dir -I %t/Inputs -enable-experimental-feature SafeInteropWrappers -print-module -module-to-print=Method -source-filename=x | %FileCheck %s
 // RUN: %target-swift-frontend -plugin-path %swift-plugin-dir -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/method.swift -dump-macro-expansions -typecheck -verify
 
-// REQUIRES: objc_interop
-
 // CHECK: class Foo {
 // CHECK:  func bar(_ p: UnsafeMutableBufferPointer<Float>)
 
diff --git a/test/Interop/ObjC/swiftify-import/objc-no-swiftify.swift b/test/Interop/ObjC/swiftify-import/objc-no-swiftify.swift
new file mode 100644
index 0000000000000..5c918bc4bec5c
--- /dev/null
+++ b/test/Interop/ObjC/swiftify-import/objc-no-swiftify.swift
@@ -0,0 +1,22 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %target-swift-ide-test -print-module -module-to-print=NoSwiftifyClang -plugin-path %swift-plugin-dir -I %S/Inputs -source-filename=x -enable-experimental-feature SafeInteropWrappers | %FileCheck %s
+
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/NoSwiftify.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s -verify -verify-additional-file %S/Inputs/objc-no-swiftify.h
+
+import NoSwiftifyClang
+
+// CHECK-NOT: @_alwaysEmitIntoClient @_disfavoredOverload public func callAutoreleaseParam
+// CHECK-NOT: @_alwaysEmitIntoClient @_disfavoredOverload public func callAutoreleaseReturn
+
+public func callAutoreleaseParam(_ p: UnsafeMutableBufferPointer<SomeClass>) {
+    // expected-error@+2{{missing argument for parameter #2 in call}}
+    // expected-error@+1{{cannot convert value of type 'UnsafeMutableBufferPointer<SomeClass>' to expected argument type 'AutoreleasingUnsafeMutablePointer<SomeClass?>'}}
+    autoreleaseParam(p)
+}
+
+public func callAutoreleaseReturn() {
+    // expected-error@+1{{cannot convert value of type 'AutoreleasingUnsafeMutablePointer<SomeClass?>?' to specified type 'UnsafeMutableBufferPointer<SomeClass>'}}
+    let p: UnsafeMutableBufferPointer<SomeClass> = autoreleaseReturn(10)
+}
\ No newline at end of file
diff --git a/test/Interop/ObjCToSwiftToObjCxx/bridge-objc-types-back-to-objcxx.swift b/test/Interop/ObjCToSwiftToObjCxx/bridge-objc-types-back-to-objcxx.swift
index 7a407f781c2e4..934553a28eba5 100644
--- a/test/Interop/ObjCToSwiftToObjCxx/bridge-objc-types-back-to-objcxx.swift
+++ b/test/Interop/ObjCToSwiftToObjCxx/bridge-objc-types-back-to-objcxx.swift
@@ -30,6 +30,16 @@
 - (void)method;
 @end
 
+typedef NS_OPTIONS(NSUInteger, ObjCKlassState) {
+  ObjCKlassStateNormal  = 0,
+};
+
+//--- ObjCTest.apinotes
+Name: ObjCTest
+Tags:
+- Name: ObjCKlassState
+  SwiftName: ObjCKlass.State
+
 //--- module.modulemap
 module ObjCTest {
     header "header.h"
@@ -37,6 +47,11 @@ module ObjCTest {
 
 //--- use-objc-types.swift
 import ObjCTest
+import Foundation
+
+@objc public class HasBlockField : NSObject {
+    @objc var foo: ((ObjCKlass.State) -> Void)?
+}
 
 public func retObjClass() -> ObjCKlass {
     return ObjCKlass()
@@ -73,6 +88,17 @@ public func retObjCClassArray() -> [ObjCKlass] {
     return []
 }
 
+public class KVOCookieMonster {
+   public static func += (lhs: KVOCookieMonster, rhs: NSKeyValueObservation) {
+      lhs.cookies.append(rhs)
+   }
+
+   private var cookies = Array<NSKeyValueObservation>()
+}
+
+// CHECK: @interface HasBlockField : NSObject
+// CHECK: @property (nonatomic, copy) void (^ _Nullable foo)(ObjCKlassState);
+// CHECK: @end
 // CHECK: SWIFT_EXTERN id <ObjCProtocol> _Nonnull $s9UseObjCTy03retB9CProtocolSo0bE0_pyF(void) SWIFT_NOEXCEPT SWIFT_CALL; // retObjCProtocol()
 // CHECK-NEXT: #endif
 // CHECK-NEXT: #if defined(__OBJC__)
@@ -94,7 +120,7 @@ public func retObjCClassArray() -> [ObjCKlass] {
 // CHECK-NEXT: template<>
 // CHECK-NEXT: struct TypeMetadataTrait<ObjCKlass*> {
 // CHECK-NEXT:   static SWIFT_INLINE_PRIVATE_HELPER void * _Nonnull getTypeMetadata() {
-// CHECK-NEXT:     return _impl::$sSo9ObjCKlassCMa(0)._0;
+// CHECK-NEXT:     return UseObjCTy::_impl::$sSo9ObjCKlassCMa(0)._0;
 // CHECK-NEXT:   }
 // CHECK-NEXT: };
 
diff --git a/test/Interop/SwiftToCxx/class/nested-classes-in-cxx.swift b/test/Interop/SwiftToCxx/class/nested-classes-in-cxx.swift
index 5eae53d9b1be4..69f82816a6513 100644
--- a/test/Interop/SwiftToCxx/class/nested-classes-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/class/nested-classes-in-cxx.swift
@@ -1,6 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -enable-library-evolution -typecheck -module-name Classes -clang-header-expose-decls=all-public -emit-clang-header-path %t/classes.h
+// RUN: %check-interop-cxx-header-in-clang(%t/classes.h -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY -std=c++17)
 
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -typecheck -module-name Classes -clang-header-expose-decls=all-public -emit-clang-header-path %t/classes.h
 // RUN: %check-interop-cxx-header-in-clang(%t/classes.h -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY -std=c++17)
 
 public class RecordConfig {
diff --git a/test/Interop/SwiftToCxx/class/swift-actor-execution.cpp b/test/Interop/SwiftToCxx/class/swift-actor-execution.cpp
index 0ea535ee55648..7a828c2a1d9ef 100644
--- a/test/Interop/SwiftToCxx/class/swift-actor-execution.cpp
+++ b/test/Interop/SwiftToCxx/class/swift-actor-execution.cpp
@@ -1,19 +1,19 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend %S/swift-actor-in-cxx.swift -module-name Actor -clang-header-expose-decls=has-expose-attr -typecheck -verify -emit-clang-header-path %t/actor.h -disable-availability-checking
+// RUN: %target-swift-frontend %S/swift-actor-in-cxx.swift -module-name Actor -clang-header-expose-decls=has-expose-attr -typecheck -verify -emit-clang-header-path %t/actor.h
 
 // RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-actor-execution.o
-// RUN: %target-interop-build-swift %S/swift-actor-in-cxx.swift -o %t/swift-actor-execution -Xlinker %t/swift-actor-execution.o -module-name Actor -Xfrontend -entry-point-function-name -Xfrontend swiftMain -Xfrontend -disable-availability-checking
+// RUN: %target-interop-build-swift %S/swift-actor-in-cxx.swift -o %t/swift-actor-execution -Xlinker %t/swift-actor-execution.o -module-name Actor -Xfrontend -entry-point-function-name -Xfrontend swiftMain
 
 // RUN: %target-codesign %t/swift-actor-execution
 // RUN: %target-run %t/swift-actor-execution | %FileCheck %s
 
 // RUN: %empty-directory(%t-evo)
 
-// RUN: %target-swift-frontend %S/swift-actor-in-cxx.swift -module-name Actor -clang-header-expose-decls=has-expose-attr -enable-library-evolution -typecheck -verify -emit-clang-header-path %t-evo/actor.h -disable-availability-checking
+// RUN: %target-swift-frontend %S/swift-actor-in-cxx.swift -module-name Actor -clang-header-expose-decls=has-expose-attr -enable-library-evolution -typecheck -verify -emit-clang-header-path %t-evo/actor.h
 
 // RUN: %target-interop-build-clangxx -c %s -I %t-evo -o %t-evo/swift-actor-execution.o
-// RUN: %target-interop-build-swift %S/swift-actor-in-cxx.swift -o %t-evo/swift-actor-execution-evo -Xlinker %t-evo/swift-actor-execution.o -module-name Actor -enable-library-evolution -Xfrontend -entry-point-function-name -Xfrontend swiftMain -Xfrontend -disable-availability-checking
+// RUN: %target-interop-build-swift %S/swift-actor-in-cxx.swift -o %t-evo/swift-actor-execution-evo -Xlinker %t-evo/swift-actor-execution.o -module-name Actor -enable-library-evolution -Xfrontend -entry-point-function-name -Xfrontend swiftMain
 
 // RUN: %target-codesign %t-evo/swift-actor-execution-evo
 // RUN: %target-run %t-evo/swift-actor-execution-evo | %FileCheck %s
diff --git a/test/Interop/SwiftToCxx/class/swift-class-ordering.swift b/test/Interop/SwiftToCxx/class/swift-class-ordering.swift
index 1bd8355053e22..3f5b4060a9151 100644
--- a/test/Interop/SwiftToCxx/class/swift-class-ordering.swift
+++ b/test/Interop/SwiftToCxx/class/swift-class-ordering.swift
@@ -9,3 +9,13 @@ public class SwiftNode {
 public struct SwiftLinkedList {
   public var head: SwiftNode
 }
+
+public class B
+{
+    public init() {}
+}
+
+public class A
+{
+    public init(_ b: B) {}
+}
diff --git a/test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch-arm64e.swift b/test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch-arm64e.swift
index d4e4714c5f944..da8bb7bbef99f 100644
--- a/test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch-arm64e.swift
+++ b/test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch-arm64e.swift
@@ -16,7 +16,7 @@
 // CHECK-NEXT: void **vtable_ = *selfPtr_;
 // CHECK-NEXT: #endif
 // CHECK-NEXT: struct FTypeAddress {
-// CHECK-NEXT: decltype(_impl::$s5Class04BaseA0C13virtualMethodyyF) * __ptrauth_swift_class_method_pointer([[#AUTH:]]) func;
+// CHECK-NEXT: decltype(Class::_impl::$s5Class04BaseA0C13virtualMethodyyF) * __ptrauth_swift_class_method_pointer([[#AUTH:]]) func;
 // CHECK-NEXT: };
 // CHECK-NEXT: FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM1:]] / sizeof(void *));
 // CHECK-NEXT:   (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
diff --git a/test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch.swift b/test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch.swift
index 8d2896cd422e8..7cdd1fbe3ec5a 100644
--- a/test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch.swift
+++ b/test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch.swift
@@ -124,7 +124,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT: void **vtable_ = *selfPtr_;
 // CHECK-NEXT: #endif
 // CHECK-NEXT: struct FTypeAddress {
-// CHECK-NEXT: decltype(_impl::$s5Class04BaseA0C13virtualMethodyyF) * func;
+// CHECK-NEXT: decltype(Class::_impl::$s5Class04BaseA0C13virtualMethodyyF) * func;
 // CHECK-NEXT: };
 // CHECK-NEXT: FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM1:]] / sizeof(void *));
 // CHECK-NEXT: (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -138,7 +138,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT: void **vtable_ = *selfPtr_;
 // CHECK-NEXT: #endif
 // CHECK-NEXT: struct FTypeAddress {
-// CHECK-NEXT: decltype(_impl::$s5Class04BaseA0C016virtualMethodIntE0yS2iF) * func;
+// CHECK-NEXT: decltype(Class::_impl::$s5Class04BaseA0C016virtualMethodIntE0yS2iF) * func;
 // CHECK-NEXT: };
 // CHECK-NEXT: FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM2:]] / sizeof(void *));
 // CHECK-NEXT:   return (* fptrptr_->func)(x, ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -156,7 +156,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:   void **vtable_ = *selfPtr_;
 // CHECK-NEXT:   #endif
 // CHECK-NEXT:   struct FTypeAddress {
-// CHECK-NEXT:   decltype(_impl::$s5Class04BaseA0C19virtualComputedPropSivg) * func;
+// CHECK-NEXT:   decltype(Class::_impl::$s5Class04BaseA0C19virtualComputedPropSivg) * func;
 // CHECK-NEXT:   };
 // CHECK-NEXT:   FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM3:]] / sizeof(void *));
 // CHECK-NEXT:     return (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -170,7 +170,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:   void **vtable_ = *selfPtr_;
 // CHECK-NEXT:   #endif
 // CHECK-NEXT:   struct FTypeAddress {
-// CHECK-NEXT:   decltype(_impl::$s5Class04BaseA0C21virtualComputedGetSets5Int64Vvg) * func;
+// CHECK-NEXT:   decltype(Class::_impl::$s5Class04BaseA0C21virtualComputedGetSets5Int64Vvg) * func;
 // CHECK-NEXT:   };
 // CHECK-NEXT:   FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM4:]] / sizeof(void *));
 // CHECK-NEXT:     return (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -184,7 +184,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:   void **vtable_ = *selfPtr_;
 // CHECK-NEXT:   #endif
 // CHECK-NEXT:   struct FTypeAddress {
-// CHECK-NEXT:   decltype(_impl::$s5Class04BaseA0C21virtualComputedGetSets5Int64Vvs) * func;
+// CHECK-NEXT:   decltype(Class::_impl::$s5Class04BaseA0C21virtualComputedGetSets5Int64Vvs) * func;
 // CHECK-NEXT:   };
 // CHECK-NEXT:   FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM5:]] / sizeof(void *));
 // CHECK-NEXT:   (* fptrptr_->func)(newValue, ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -198,7 +198,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:   void **vtable_ = *selfPtr_;
 // CHECK-NEXT:   #endif
 // CHECK-NEXT:   struct FTypeAddress {
-// CHECK-NEXT:   decltype(_impl::$s5Class04BaseA0C10storedPropSivg) * func;
+// CHECK-NEXT:   decltype(Class::_impl::$s5Class04BaseA0C10storedPropSivg) * func;
 // CHECK-NEXT:   };
 // CHECK-NEXT:   FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM7:]] / sizeof(void *));
 // CHECK-NEXT:   return (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -212,7 +212,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:   void **vtable_ = *selfPtr_;
 // CHECK-NEXT:   #endif
 // CHECK-NEXT:   struct FTypeAddress {
-// CHECK-NEXT:   decltype(_impl::$s5Class04BaseA0C10storedPropSivs) * func;
+// CHECK-NEXT:   decltype(Class::_impl::$s5Class04BaseA0C10storedPropSivs) * func;
 // CHECK-NEXT:   };
 // CHECK-NEXT:   FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM8:]] / sizeof(void *));
 // CHECK-NEXT:     (* fptrptr_->func)(value, ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -226,7 +226,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:    void **vtable_ = *selfPtr_;
 // CHECK-NEXT:    #endif
 // CHECK-NEXT:    struct FTypeAddress {
-// CHECK-NEXT:    decltype(_impl::$s5Class04BaseA0CyS2icig) * func;
+// CHECK-NEXT:    decltype(Class::_impl::$s5Class04BaseA0CyS2icig) * func;
 // CHECK-NEXT:    };
 // CHECK-NEXT:    FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM10:]] / sizeof(void *));
 // CHECK-NEXT:    return (* fptrptr_->func)(i, ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -240,7 +240,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:   void **vtable_ = *selfPtr_;
 // CHECK-NEXT:   #endif
 // CHECK-NEXT:   struct FTypeAddress {
-// CHECK-NEXT:   decltype(_impl::$s5Class07DerivedA0C13virtualMethodyyF) * func;
+// CHECK-NEXT:   decltype(Class::_impl::$s5Class07DerivedA0C13virtualMethodyyF) * func;
 // CHECK-NEXT:   };
 // CHECK-NEXT:   FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM1]] / sizeof(void *));
 // CHECK-NEXT:   (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -254,7 +254,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:     void **vtable_ = *selfPtr_;
 // CHECK-NEXT:     #endif
 // CHECK-NEXT:     struct FTypeAddress {
-// CHECK-NEXT:     decltype(_impl::$s5Class07DerivedA0C016virtualMethodIntE0yS2iF) * func;
+// CHECK-NEXT:     decltype(Class::_impl::$s5Class07DerivedA0C016virtualMethodIntE0yS2iF) * func;
 // CHECK-NEXT:     };
 // CHECK-NEXT:     FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM2]] / sizeof(void *));
 // CHECK-NEXT:     return (* fptrptr_->func)(x, ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -268,7 +268,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:   void **vtable_ = *selfPtr_;
 // CHECK-NEXT:   #endif
 // CHECK-NEXT:   struct FTypeAddress {
-// CHECK-NEXT:   decltype(_impl::$s5Class07DerivedA0C015virtualMethodInB0yAA04BaseA0CAFF) * func;
+// CHECK-NEXT:   decltype(Class::_impl::$s5Class07DerivedA0C015virtualMethodInB0yAA04BaseA0CAFF) * func;
 // CHECK-NEXT:   };
 // CHECK-NEXT:   FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM11:]] / sizeof(void *));
 // CHECK-NEXT:   return _impl::_impl_BaseClass::makeRetained((* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(x), ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this)));
@@ -282,7 +282,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:     void **vtable_ = *selfPtr_;
 // CHECK-NEXT:     #endif
 // CHECK-NEXT:     struct FTypeAddress {
-// CHECK-NEXT:     decltype(_impl::$s5Class07DerivedA0C19virtualComputedPropSivg) * func;
+// CHECK-NEXT:     decltype(Class::_impl::$s5Class07DerivedA0C19virtualComputedPropSivg) * func;
 // CHECK-NEXT:     };
 // CHECK-NEXT:     FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM3]] / sizeof(void *));
 // CHECK-NEXT:       return (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -296,7 +296,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:     void **vtable_ = *selfPtr_;
 // CHECK-NEXT:     #endif
 // CHECK-NEXT:     struct FTypeAddress {
-// CHECK-NEXT:     decltype(_impl::$s5Class07DerivedA0C21virtualComputedGetSets5Int64Vvg) * func;
+// CHECK-NEXT:     decltype(Class::_impl::$s5Class07DerivedA0C21virtualComputedGetSets5Int64Vvg) * func;
 // CHECK-NEXT:     };
 // CHECK-NEXT:     FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM4]] / sizeof(void *));
 // CHECK-NEXT:     return (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -310,7 +310,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:     void **vtable_ = *selfPtr_;
 // CHECK-NEXT:     #endif
 // CHECK-NEXT:     struct FTypeAddress {
-// CHECK-NEXT:     decltype(_impl::$s5Class07DerivedA0C21virtualComputedGetSets5Int64Vvs) * func;
+// CHECK-NEXT:     decltype(Class::_impl::$s5Class07DerivedA0C21virtualComputedGetSets5Int64Vvs) * func;
 // CHECK-NEXT:     };
 // CHECK-NEXT:     FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM5]] / sizeof(void *));
 // CHECK-NEXT:     (* fptrptr_->func)(newValue, ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -324,7 +324,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:     void **vtable_ = *selfPtr_;
 // CHECK-NEXT:     #endif
 // CHECK-NEXT:     struct FTypeAddress {
-// CHECK-NEXT:     decltype(_impl::$s5Class07DerivedA0C10storedPropSivg) * func;
+// CHECK-NEXT:     decltype(Class::_impl::$s5Class07DerivedA0C10storedPropSivg) * func;
 // CHECK-NEXT:     };
 // CHECK-NEXT:     FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM7]] / sizeof(void *));
 // CHECK-NEXT:       return (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -338,7 +338,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:     void **vtable_ = *selfPtr_;
 // CHECK-NEXT:     #endif
 // CHECK-NEXT:     struct FTypeAddress {
-// CHECK-NEXT:     decltype(_impl::$s5Class07DerivedA0C10storedPropSivs) * func;
+// CHECK-NEXT:     decltype(Class::_impl::$s5Class07DerivedA0C10storedPropSivs) * func;
 // CHECK-NEXT:     };
 // CHECK-NEXT:     FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM8]] / sizeof(void *));
 // CHECK-NEXT:     (* fptrptr_->func)(newValue, ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
@@ -352,7 +352,7 @@ public func returnDerivedDerivedClass() -> DerivedDerivedClass {
 // CHECK-NEXT:    void **vtable_ = *selfPtr_;
 // CHECK-NEXT:    #endif
 // CHECK-NEXT:    struct FTypeAddress {
-// CHECK-NEXT:    decltype(_impl::$s5Class07DerivedA0CyS2icig) * func;
+// CHECK-NEXT:    decltype(Class::_impl::$s5Class07DerivedA0CyS2icig) * func;
 // CHECK-NEXT:    };
 // CHECK-NEXT:    FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM10]] / sizeof(void *));
 // CHECK-NEXT:      return (* fptrptr_->func)(i, ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
diff --git a/test/Interop/SwiftToCxx/class/swift-subclass-of-resilient-class-virtual-method-dispatch.swift b/test/Interop/SwiftToCxx/class/swift-subclass-of-resilient-class-virtual-method-dispatch.swift
index 6a7164c16b33a..1973f7fa11cd5 100644
--- a/test/Interop/SwiftToCxx/class/swift-subclass-of-resilient-class-virtual-method-dispatch.swift
+++ b/test/Interop/SwiftToCxx/class/swift-subclass-of-resilient-class-virtual-method-dispatch.swift
@@ -94,7 +94,7 @@ public func createCrossModuleDerivedDerivedClass() -> CrossModuleDerivedDerivedC
 // CHECK-NEXT: void **vtable_ = *selfPtr_;
 // CHECK-NEXT: #endif
 // CHECK-NEXT: struct FTypeAddress {
-// CHECK-NEXT: decltype(_impl::$s8UseClass018CrossModuleDerivedB0C015virtualMethodInE0yyF) * func;
+// CHECK-NEXT: decltype(UseClass::_impl::$s8UseClass018CrossModuleDerivedB0C015virtualMethodInE0yyF) * func;
 // CHECK-NEXT: };
 // CHECK-NEXT: FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + (_impl::$s8UseClass018CrossModuleDerivedB0CMo + 0) / sizeof(void *));
 // CHECK-NEXT: (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
diff --git a/test/Interop/SwiftToCxx/core/embedded-swift-execution.cpp b/test/Interop/SwiftToCxx/core/embedded-swift-execution.cpp
new file mode 100644
index 0000000000000..6b26ccfabee19
--- /dev/null
+++ b/test/Interop/SwiftToCxx/core/embedded-swift-execution.cpp
@@ -0,0 +1,23 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend %S/embedded-swift.swift -target arm64-apple-macosx15.0 -module-name Core -swift-version 6 -enable-experimental-feature Embedded -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/core.h
+
+// RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-embedded-execution.o -fno-exceptions -fno-rtti
+// RUN: %target-interop-build-swift -target arm64-apple-macosx15.0 -wmo %S/embedded-swift.swift -o %t/swift-embedded-execution -Xlinker %t/swift-embedded-execution.o -module-name Core -Xfrontend -entry-point-function-name -Xfrontend swiftMain -enable-experimental-feature Embedded -Xcc -fno-rtti -Xcc -fno-exceptions -Xlinker %swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos/libswiftUnicodeDataTables.a
+
+// RUN: %target-codesign %t/swift-embedded-execution
+// RUN: %target-run %t/swift-embedded-execution
+
+// REQUIRES: OS=macosx
+// REQUIRES: embedded_stdlib
+// REQUIRES: swift_feature_Embedded
+// REQUIRES: executable_test
+// REQUIRES: CPU=arm64e || CPU=arm64
+
+#include <assert.h>
+#include "core.h"
+
+int main() {
+  assert(Core::id(5) == 5);
+  return 0;
+}
diff --git a/test/Interop/SwiftToCxx/expose-attr/expose-swift-decls-to-cxx.swift b/test/Interop/SwiftToCxx/expose-attr/expose-swift-decls-to-cxx.swift
index fe1bdc85a00bf..bf9bf406c62ad 100644
--- a/test/Interop/SwiftToCxx/expose-attr/expose-swift-decls-to-cxx.swift
+++ b/test/Interop/SwiftToCxx/expose-attr/expose-swift-decls-to-cxx.swift
@@ -82,7 +82,7 @@ public final class ExposedClass {
 // CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedClass final
 // CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedStruct final {
 // CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedStruct2 final {
-// CHECK: ExposedStruct2(ExposedStruct2 &&)
+// CHECK: SWIFT_INLINE_THUNK ExposedStruct2 &operator =(const ExposedStruct2 &other) noexcept {
 // CHECK: }
 // CHECK-NEXT: swift::Int getY() const SWIFT_SYMBOL("{{.*}}");
 // CHECK-NEXT: void setY(swift::Int value) SWIFT_SYMBOL("{{.*}}");
diff --git a/test/Interop/SwiftToCxx/expose-attr/hidden-decls.swift b/test/Interop/SwiftToCxx/expose-attr/hidden-decls.swift
new file mode 100644
index 0000000000000..b043ed5f1ec17
--- /dev/null
+++ b/test/Interop/SwiftToCxx/expose-attr/hidden-decls.swift
@@ -0,0 +1,33 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -module-name SwiftPrivate -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/swiftprivate.h
+// RUN: %FileCheck %s < %t/swiftprivate.h
+
+// RUN: %check-interop-cxx-header-in-clang(%t/swiftprivate.h  -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY)
+
+public struct Exposed {
+    public var x: Int
+    @_expose(!Cxx)
+    public var notExposedField: Int
+}
+
+@_expose(!Cxx)
+public struct NotExposed {
+   public var x: Int  
+}
+
+extension NotExposed {
+    func notExposed() {}
+}
+
+@_expose(!Cxx)
+public func NotExposedfunction() {}
+
+@MainActor
+@_expose(!Cxx)
+public class UnavailableClass {
+}
+
+// CHECK-NOT: NotExposed
+// CHECK-NOT: notExposed
+// CHECK: Exposed
+// CHECK-NOT: UnavailableClass
diff --git a/test/Interop/SwiftToCxx/initializers/init-in-cxx.swift b/test/Interop/SwiftToCxx/initializers/init-in-cxx.swift
index 85a62e63fc45d..0f723dc4876e0 100644
--- a/test/Interop/SwiftToCxx/initializers/init-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/initializers/init-in-cxx.swift
@@ -39,7 +39,7 @@ public struct FirstSmallStruct {
 
 // CHECK: class SWIFT_SYMBOL("s:4Init16FirstSmallStructV") FirstSmallStruct final {
 // CHECK-NEXT: public:
-// CHECK:   SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
+// CHECK: SWIFT_INLINE_THUNK FirstSmallStruct &operator =(const FirstSmallStruct &other) noexcept {
 // CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK uint32_t getX() const SWIFT_SYMBOL("s:4Init16FirstSmallStructV1xs6UInt32Vvp");
 // CHECK-NEXT:   static SWIFT_INLINE_THUNK FirstSmallStruct init() SWIFT_SYMBOL("s:4Init16FirstSmallStructVACycfc");
diff --git a/test/Interop/SwiftToCxx/initializers/init-in-extension-in-cxx.swift b/test/Interop/SwiftToCxx/initializers/init-in-extension-in-cxx.swift
new file mode 100644
index 0000000000000..081e9312f084b
--- /dev/null
+++ b/test/Interop/SwiftToCxx/initializers/init-in-extension-in-cxx.swift
@@ -0,0 +1,22 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -module-name Init -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/inits.h
+// RUN: %FileCheck %s < %t/inits.h
+
+// RUN: %check-interop-cxx-header-in-clang(%t/inits.h -Wno-unused-function -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY)
+
+public struct OverloadedInitInExtension {
+    let x: Int
+
+    public init(_ x: Int) {
+        self.x = x
+    }
+}
+extension OverloadedInitInExtension {
+    public init(viaExtension x: Int) {
+        self.x = x
+    }
+}
+
+// Make sure we don't emit ambiguous overloads:
+// CHECK: static SWIFT_INLINE_THUNK OverloadedInitInExtension init(swift::Int x)
+// CHECK-NOT: static SWIFT_INLINE_THUNK OverloadedInitInExtension init(swift::Int x)
diff --git a/test/Interop/SwiftToCxx/methods/method-in-cxx.swift b/test/Interop/SwiftToCxx/methods/method-in-cxx.swift
index e959238894ebd..bee8a55d0bd6a 100644
--- a/test/Interop/SwiftToCxx/methods/method-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/methods/method-in-cxx.swift
@@ -105,7 +105,7 @@ public final class PassStructInClassMethod {
 // CHECK-NEXT:   static SWIFT_INLINE_THUNK LargeStruct staticFinalClassMethod(swift::Int x) SWIFT_SYMBOL("s:7Methods09ClassWithA0C011staticFinalB6Method1xAA11LargeStructVSi_tFZ");
 
 // CHECK: class SWIFT_SYMBOL("s:7Methods11LargeStructV") LargeStruct final {
-// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_THUNK LargeStruct &operator =(const LargeStruct &other) noexcept {
 // CHECK: }
 // CHECK-NEXT: SWIFT_INLINE_THUNK LargeStruct doubled() const SWIFT_SYMBOL("s:7Methods11LargeStructV7doubledACyF");
 // CHECK-NEXT: SWIFT_INLINE_THUNK void dump() const SWIFT_SYMBOL("s:7Methods11LargeStructV4dumpyyF");
diff --git a/test/Interop/SwiftToCxx/methods/method-in-extension-in-cxx.swift b/test/Interop/SwiftToCxx/methods/method-in-extension-in-cxx.swift
new file mode 100644
index 0000000000000..e5525653e66af
--- /dev/null
+++ b/test/Interop/SwiftToCxx/methods/method-in-extension-in-cxx.swift
@@ -0,0 +1,22 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -module-name Method -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/methods.h
+// RUN: %FileCheck %s < %t/methods.h
+
+// RUN: %check-interop-cxx-header-in-clang(%t/methods.h -Wno-unused-function -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY)
+
+public struct OverloadedMethodInExtension {
+    var x: Int
+
+    public mutating func add(_ x: Int) {
+        self.x += x
+    }
+}
+extension OverloadedMethodInExtension {
+    public mutating func add(viaExtension x: Int) {
+        self.x += x
+    }
+}
+
+// Make sure we don't emit ambiguous overloads:
+// CHECK: SWIFT_INLINE_THUNK void OverloadedMethodInExtension::add(swift::Int x)
+// CHECK-NOT: SWIFT_INLINE_THUNK void OverloadedMethodInExtension::add(swift::Int x)
diff --git a/test/Interop/SwiftToCxx/methods/mutating-method-in-cxx.swift b/test/Interop/SwiftToCxx/methods/mutating-method-in-cxx.swift
index c340f1144949f..d108ce5c5e442 100644
--- a/test/Interop/SwiftToCxx/methods/mutating-method-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/methods/mutating-method-in-cxx.swift
@@ -57,7 +57,7 @@ public struct SmallStruct {
 // CHECK: SWIFT_EXTERN void $s7Methods11SmallStructV6invertyyF(SWIFT_CONTEXT void * _Nonnull _self) SWIFT_NOEXCEPT SWIFT_CALL; // invert()
 
 // CHECK: class SWIFT_SYMBOL("s:7Methods11LargeStructV") LargeStruct final {
-// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_THUNK LargeStruct &operator =(const LargeStruct &other) noexcept {
 // CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK void dump() const SWIFT_SYMBOL("s:7Methods11LargeStructV4dumpyyF");
 // CHECK-NEXT:   SWIFT_INLINE_THUNK void double_() SWIFT_SYMBOL("s:7Methods11LargeStructV6doubleyyF");
@@ -65,7 +65,7 @@ public struct SmallStruct {
 // CHECK-NEXT: private
 
 // CHECK: class SWIFT_SYMBOL("s:7Methods11SmallStructV") SmallStruct final {
-// CHECK:   SWIFT_INLINE_PRIVATE_HELPER SmallStruct(SmallStruct &&)
+// CHECK: SWIFT_INLINE_THUNK SmallStruct &operator =(const SmallStruct &other) noexcept {
 // CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK void dump() const SWIFT_SYMBOL("s:7Methods11SmallStructV4dumpyyF");
 // CHECK-NEXT:   SWIFT_INLINE_THUNK SmallStruct scale(float y) SWIFT_SYMBOL("s:7Methods11SmallStructV5scaleyACSfF");
diff --git a/test/Interop/SwiftToCxx/properties/getter-in-cxx.swift b/test/Interop/SwiftToCxx/properties/getter-in-cxx.swift
index c868110869e03..9cefc0c6dc75e 100644
--- a/test/Interop/SwiftToCxx/properties/getter-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/properties/getter-in-cxx.swift
@@ -10,7 +10,7 @@ public struct FirstSmallStruct {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) FirstSmallStruct final {
 // CHECK: public:
-// CHECK:   SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
+// CHECK:   SWIFT_INLINE_THUNK FirstSmallStruct &operator =(const FirstSmallStruct &other) noexcept {
 // CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK uint32_t getX() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:   private:
@@ -37,7 +37,7 @@ public struct LargeStruct {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) LargeStruct final {
 // CHECK: public:
-// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_THUNK LargeStruct &operator =(const LargeStruct &other) noexcept {
 // CHECK: }
 // CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX1() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX2() const SWIFT_SYMBOL({{.*}});
@@ -94,7 +94,7 @@ public struct SmallStructWithGetters {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) SmallStructWithGetters final {
 // CHECK: public:
-// CHECK:   SWIFT_INLINE_PRIVATE_HELPER SmallStructWithGetters(SmallStructWithGetters &&)
+// CHECK: SWIFT_INLINE_THUNK SmallStructWithGetters &operator =(const SmallStructWithGetters &other) noexcept {
 // CHECK: }
 // CHECK-NEXT:  SWIFT_INLINE_THUNK uint32_t getStoredInt() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:  SWIFT_INLINE_THUNK swift::Int getComputedInt() const SWIFT_SYMBOL({{.*}});
diff --git a/test/Interop/SwiftToCxx/properties/setter-in-cxx.swift b/test/Interop/SwiftToCxx/properties/setter-in-cxx.swift
index 656a6f22e03d1..b4030ed466022 100644
--- a/test/Interop/SwiftToCxx/properties/setter-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/properties/setter-in-cxx.swift
@@ -10,7 +10,7 @@ public struct FirstSmallStruct {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) FirstSmallStruct final {
 // CHECK: public:
-// CHECK:   SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
+// CHECK: SWIFT_INLINE_THUNK FirstSmallStruct &operator =(const FirstSmallStruct &other) noexcept {
 // CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK uint32_t getX() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:   SWIFT_INLINE_THUNK void setX(uint32_t value) SWIFT_SYMBOL({{.*}});
@@ -32,7 +32,7 @@ public struct LargeStruct {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) LargeStruct final {
 // CHECK: public:
-// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_THUNK LargeStruct &operator =(const LargeStruct &other) noexcept {
 // CHECK: }
 // CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX1() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT: SWIFT_INLINE_THUNK void setX1(swift::Int value) SWIFT_SYMBOL({{.*}});
@@ -111,7 +111,7 @@ public struct SmallStructWithProps {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) SmallStructWithProps final {
 // CHECK: public:
-// CHECK:   SWIFT_INLINE_PRIVATE_HELPER SmallStructWithProps(SmallStructWithProps &&)
+// CHECK: SWIFT_INLINE_THUNK SmallStructWithProps &operator =(const SmallStructWithProps &other) noexcept {
 // CHECK: }
 // CHECK-NEXT:    SWIFT_INLINE_THUNK uint32_t getStoredInt() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:    SWIFT_INLINE_THUNK void setStoredInt(uint32_t value) SWIFT_SYMBOL({{.*}});
diff --git a/test/Interop/SwiftToCxx/stdlib/core-foundation-types-in-cxx.swift b/test/Interop/SwiftToCxx/stdlib/core-foundation-types-in-cxx.swift
index 0a924713c4cea..60e5260e4636c 100644
--- a/test/Interop/SwiftToCxx/stdlib/core-foundation-types-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/stdlib/core-foundation-types-in-cxx.swift
@@ -4,6 +4,7 @@
 // RUN: %FileCheck %s < %t/UseCoreFoundation.h
 
 // RUN: echo "#include <netinet/in.h>" > %t/full-header.h
+// RUN: echo "#include <dispatch/dispatch.h>" >> %t/full-header.h
 // RUN: cat %t/UseCoreFoundation.h >> %t/full-header.h
 // RUN: %target-interop-build-clangxx -std=gnu++20 -fobjc-arc -c -x objective-c++-header %t/full-header.h -o %t/o.o
 
@@ -11,11 +12,20 @@
 
 import CoreFoundation
 import Foundation
+import Dispatch
+
+public func testDispatch(x: DispatchSemaphore) {}
 
 public func foobar(_ a: CFData) -> Bool {
     true
 }
 
+public func returnsCFDate() -> CFDate? {
+    nil
+}
+
+public func takesCFDate(x: CFDate?) {}
+
 public func networkThing() -> in_addr? {
     return nil
 }
@@ -25,4 +35,11 @@ public enum MyEnum {
 }
 
 // CHECK: SWIFT_EXTERN bool $s17UseCoreFoundation6foobarySbSo9CFDataRefaF(CFDataRef _Nonnull a) SWIFT_NOEXCEPT SWIFT_CALL; // foobar(_:)
+// CHECK: SWIFT_EXTERN CFDateRef _Nullable $s17UseCoreFoundation13returnsCFDateSo0E3RefaSgyF(void) SWIFT_NOEXCEPT SWIFT_CALL; // returnsCFDate()
+// CHECK: SWIFT_EXTERN void $s17UseCoreFoundation11takesCFDate1xySo0E3RefaSg_tF(CFDateRef _Nullable x) SWIFT_NOEXCEPT SWIFT_CALL; // takesCFDate(x:)
+// CHECK: SWIFT_EXTERN void $s17UseCoreFoundation12testDispatch1xySo21OS_dispatch_semaphoreC_tF(dispatch_semaphore_t _Nonnull x) SWIFT_NOEXCEPT SWIFT_CALL; // testDispatch(x:)
+
 // CHECK: SWIFT_INLINE_THUNK swift::Optional<in_addr> networkThing() noexcept SWIFT_SYMBOL("s:17UseCoreFoundation12networkThingSo7in_addrVSgyF") SWIFT_WARN_UNUSED_RESULT {
+// CHECK: SWIFT_INLINE_THUNK CFDateRef _Nullable returnsCFDate() noexcept SWIFT_SYMBOL("s:17UseCoreFoundation13returnsCFDateSo0E3RefaSgyF") SWIFT_WARN_UNUSED_RESULT {
+// CHECK: SWIFT_INLINE_THUNK void takesCFDate(CFDateRef _Nullable x) noexcept SWIFT_SYMBOL("s:17UseCoreFoundation11takesCFDate1xySo0E3RefaSg_tF") {
+// CHECK: SWIFT_INLINE_THUNK void testDispatch(dispatch_semaphore_t _Nonnull x) noexcept SWIFT_SYMBOL("s:17UseCoreFoundation12testDispatch1xySo21OS_dispatch_semaphoreC_tF") {
diff --git a/test/Interop/SwiftToCxx/stdlib/foundation-type-not-exposed-by-default-to-cxx.swift b/test/Interop/SwiftToCxx/stdlib/foundation-type-not-exposed-by-default-to-cxx.swift
index cf8ef20b2014c..b1779211c630c 100644
--- a/test/Interop/SwiftToCxx/stdlib/foundation-type-not-exposed-by-default-to-cxx.swift
+++ b/test/Interop/SwiftToCxx/stdlib/foundation-type-not-exposed-by-default-to-cxx.swift
@@ -1,8 +1,10 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend %s -module-name UseFoundation -enable-experimental-cxx-interop -typecheck -verify -emit-clang-header-path %t/UseFoundation.h
+// RUN: %target-swift-frontend %s -module-name UseFoundation -enable-experimental-cxx-interop -typecheck -verify -emit-clang-header-path %t/UseFoundation.h -enable-experimental-feature RequiresObjC=CoreGraphics,Foundation
 // RUN: %FileCheck %s < %t/UseFoundation.h
 
+// RUN: %check-interop-cxx-header-in-clang(%t/UseFoundation.h -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY)
+
 // REQUIRES: objc_interop
 
 import Foundation
@@ -12,4 +14,8 @@ public enum UseFoundationEnum {
     case B
 }
 
+public func f() -> Decimal {
+    Decimal()
+}
+
 // CHECK: class UseFoundationEnum { } SWIFT_UNAVAILABLE_MSG("Swift enum 'UseFoundationEnum' cannot be represented in C++");
diff --git a/test/Interop/SwiftToCxx/stdlib/string/string-to-nsstring.mm b/test/Interop/SwiftToCxx/stdlib/string/string-to-nsstring.mm
index b9fdf93379147..ebea414cf2ad3 100644
--- a/test/Interop/SwiftToCxx/stdlib/string/string-to-nsstring.mm
+++ b/test/Interop/SwiftToCxx/stdlib/string/string-to-nsstring.mm
@@ -69,5 +69,34 @@ int main() {
     assert(std::string(nsStr.UTF8String) == "nsstr");
     assert([nsStr2 isEqualToString:nsStr]);
   }
+
+  NSString *nsStrContainingUnicode = @"👨‍💻👩‍💻åäö";
+  {
+    swift::String swiftStr = swift::String::init(nsStrContainingUnicode);
+    assert(std::string(swiftStr) == "👨‍💻👩‍💻åäö");
+  }
+
+  {
+    NSString* arabic_ns = @"طاب يومك";
+    auto swift_arabic = String::init(arabic_ns);
+    auto std_arabic = (std::string)swift_arabic;
+    assert(std_arabic == "طاب يومك");
+    
+    NSString* mixed_ns = @"Hello مرحبا World";
+    auto swift_mixed = String::init(mixed_ns);
+    auto std_mixed = (std::string)swift_mixed;
+    assert(std_mixed == "Hello مرحبا World");
+    
+    NSString* hebrew_ns = @"שלום עולם";
+    auto swift_hebrew = String::init(hebrew_ns);
+    auto std_hebrew = (std::string)swift_hebrew;
+    assert(std_hebrew == "שלום עולם");
+    
+    NSString* chinese_ns = @"你好世界";
+    auto swift_chinese = String::init(chinese_ns);
+    auto std_chinese = (std::string)swift_chinese;
+    assert(std_chinese == "你好世界");
+  }
+
   return 0;
 }
diff --git a/test/Interop/SwiftToCxx/stdlib/swift-simd-in-cxx-execution.cpp b/test/Interop/SwiftToCxx/stdlib/swift-simd-in-cxx-execution.cpp
new file mode 100644
index 0000000000000..060f7a92838fa
--- /dev/null
+++ b/test/Interop/SwiftToCxx/stdlib/swift-simd-in-cxx-execution.cpp
@@ -0,0 +1,32 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend %S/swift-simd-in-cxx.swift -module-name SIMD -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/simd.h
+
+// RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-simd-execution.o
+// RUN: %target-interop-build-swift %S/swift-simd-in-cxx.swift -o %t/swift-simd-execution -Xlinker %t/swift-simd-execution.o -module-name SIMD -Xfrontend -entry-point-function-name -Xfrontend swiftMain
+
+// RUN: %target-codesign %t/swift-simd-execution
+// RUN: %target-run %t/swift-simd-execution | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: rdar157848231
+
+#include "simd.h"
+#include <assert.h>
+#include <iostream>
+
+int main() {
+  swift_float3 vec{1.0, 2.0, 3.0};
+  SIMD::swiftThingSIMD(vec);
+  // CHECK: SIMD3<Float>(1.0, 2.0, 3.0)
+  SIMD::swiftThingSIMD2(vec);
+  // CHECK: SIMD3<Float>(1.0, 2.0, 3.0)
+  swift_float3 vec2 = SIMD::swiftThingSIMD3();
+  std::cout << vec2.x << " " << vec2.y << " " << vec2.z << "\n";
+  // CHECK: 4 5 6
+  vec2 = SIMD::swiftThingSIMD4();
+  std::cout << vec2.x << " " << vec2.y << " " << vec2.z << "\n";
+  // CHECK: 4 5 6
+  return 0;
+}
+
diff --git a/test/Interop/SwiftToCxx/stdlib/swift-simd-in-cxx.swift b/test/Interop/SwiftToCxx/stdlib/swift-simd-in-cxx.swift
new file mode 100644
index 0000000000000..c54be05629bd0
--- /dev/null
+++ b/test/Interop/SwiftToCxx/stdlib/swift-simd-in-cxx.swift
@@ -0,0 +1,61 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend %s -module-name UseSIMD -cxx-interoperability-mode=default -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/UseSIMD.h
+// RUN: %FileCheck %s < %t/UseSIMD.h
+
+// RUN: %target-interop-build-clangxx -std=gnu++20 -fobjc-arc -c -x objective-c++-header %t/UseSIMD.h -o %t/o.o
+
+// REQUIRES: objc_interop
+// REQUIRES: rdar157848231
+
+import simd
+
+public func swiftThingScalar(a: Float) {}
+
+public func swiftThingSIMD(a: float3) {
+    print(a)
+}
+
+public func swiftThingSIMD2(a: simd_float3) {
+    print(a)
+}
+
+public func swiftThingSIMD3() -> float3 {
+    float3(4, 5, 6)
+}
+
+public func swiftThingSIMD4() -> simd_float3 {
+    simd_float3(4, 5, 6)
+}
+
+// CHECK: SWIFT_EXTERN void $s7UseSIMD010swiftThingB01ays5SIMD3VySfG_tF(struct swift_interop_passStub_UseSIMD_swift_float4_0_16 a) SWIFT_NOEXCEPT SWIFT_CALL; // swiftThingSIMD(a:)
+// CHECK: SWIFT_EXTERN void $s7UseSIMD15swiftThingSIMD21ays5SIMD3VySfG_tF(struct swift_interop_passStub_UseSIMD_swift_float4_0_16 a) SWIFT_NOEXCEPT SWIFT_CALL; // swiftThingSIMD2(a:)
+// CHECK: SWIFT_EXTERN struct swift_interop_returnStub_UseSIMD_swift_float4_0_16 $s7UseSIMD15swiftThingSIMD3s0E0VySfGyF(void) SWIFT_NOEXCEPT SWIFT_CALL; // swiftThingSIMD3()
+// CHECK: SWIFT_EXTERN struct swift_interop_returnStub_UseSIMD_swift_float4_0_16 $s7UseSIMD15swiftThingSIMD4s5SIMD3VySfGyF(void) SWIFT_NOEXCEPT SWIFT_CALL; // swiftThingSIMD4()
+// CHECK: SWIFT_EXTERN void $s7UseSIMD16swiftThingScalar1aySf_tF(float a) SWIFT_NOEXCEPT SWIFT_CALL; // swiftThingScalar(a:)
+
+// CHECK:      SWIFT_INLINE_THUNK void swiftThingSIMD(swift_float3 a) noexcept SWIFT_SYMBOL("s:7UseSIMD010swiftThingB01ays5SIMD3VySfG_tF") {
+// CHECK-NEXT:   UseSIMD::_impl::$s7UseSIMD010swiftThingB01ays5SIMD3VySfG_tF(UseSIMD::_impl::swift_interop_passDirect_UseSIMD_swift_float4_0_16(reinterpret_cast<const char *>(swift::_impl::getOpaquePointer(a))));
+// CHECK-NEXT: }
+
+// CHECK:      WIFT_INLINE_THUNK void swiftThingSIMD2(swift_float3 a) noexcept SWIFT_SYMBOL("s:7UseSIMD15swiftThingSIMD21ays5SIMD3VySfG_tF") {
+// CHECK-NEXT:   UseSIMD::_impl::$s7UseSIMD15swiftThingSIMD21ays5SIMD3VySfG_tF(UseSIMD::_impl::swift_interop_passDirect_UseSIMD_swift_float4_0_16(reinterpret_cast<const char *>(swift::_impl::getOpaquePointer(a))));
+// CHECK-NEXT: }
+
+// CHECK:      SWIFT_INLINE_THUNK swift_float3 swiftThingSIMD3() noexcept SWIFT_SYMBOL("s:7UseSIMD15swiftThingSIMD3s0E0VySfGyF") SWIFT_WARN_UNUSED_RESULT {
+// CHECK-NEXT: alignas(alignof(swift_float3)) char storage[sizeof(swift_float3)];
+// CHECK-NEXT: auto * _Nonnull storageObjectPtr = reinterpret_cast<swift_float3 *>(storage);
+// CHECK-NEXT: UseSIMD::_impl::swift_interop_returnDirect_UseSIMD_swift_float4_0_16(storage, UseSIMD::_impl::$s7UseSIMD15swiftThingSIMD3s0E0VySfGyF());
+// CHECK-NEXT: return *storageObjectPtr;
+// CHECK-NEXT: }
+
+// CHECK:      SWIFT_INLINE_THUNK swift_float3 swiftThingSIMD4() noexcept SWIFT_SYMBOL("s:7UseSIMD15swiftThingSIMD4s5SIMD3VySfGyF") SWIFT_WARN_UNUSED_RESULT {
+// CHECK-NEXT: alignas(alignof(swift_float3)) char storage[sizeof(swift_float3)];
+// CHECK-NEXT: auto * _Nonnull storageObjectPtr = reinterpret_cast<swift_float3 *>(storage);
+// CHECK-NEXT: UseSIMD::_impl::swift_interop_returnDirect_UseSIMD_swift_float4_0_16(storage, UseSIMD::_impl::$s7UseSIMD15swiftThingSIMD4s5SIMD3VySfGyF());
+// CHECK-NEXT: return *storageObjectPtr;
+// CHECK-NEXT: }
+
+// CHECK:      SWIFT_INLINE_THUNK void swiftThingScalar(float a) noexcept SWIFT_SYMBOL("s:7UseSIMD16swiftThingScalar1aySf_tF") {
+// CHECK-NEXT:   UseSIMD::_impl::$s7UseSIMD16swiftThingScalar1aySf_tF(a);
+// CHECK-NEXT: }
diff --git a/test/Interop/SwiftToCxx/stdlib/swift-stdlib-in-cxx.swift b/test/Interop/SwiftToCxx/stdlib/swift-stdlib-in-cxx.swift
index ffbceace05e89..e3455dfdf2efb 100644
--- a/test/Interop/SwiftToCxx/stdlib/swift-stdlib-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/stdlib/swift-stdlib-in-cxx.swift
@@ -81,13 +81,10 @@
 // CHECK:  }
 // CHECK-NEXT:  SWIFT_INLINE_THUNK String &operator =(const String &other) noexcept {
 // CHECK:  }
-// CHECK-NEXT:  SWIFT_INLINE_THUNK String &operator =(String &&other) = delete;
-// CHECK-NEXT:  SWIFT_INLINE_PRIVATE_HELPER String(String &&) noexcept {
-// CHECK: }
 // CHECK-NEXT:  static SWIFT_INLINE_THUNK String init() SWIFT_SYMBOL({{.*}});
 // CHECK:  SWIFT_INLINE_THUNK void append(const String& other)
-// CHECK:  SWIFT_INLINE_THUNK UTF8View getUtf8() const SWIFT_SYMBOL({{.*}});
-// CHECK-NEXT:  SWIFT_INLINE_THUNK void setUtf8(const UTF8View& newValue) SWIFT_SYMBOL({{.*}});
+// CHECK:  SWIFT_INLINE_THUNK __StringNested::UTF8View getUtf8() const SWIFT_SYMBOL({{.*}});
+// CHECK-NEXT:  SWIFT_INLINE_THUNK void setUtf8(const __StringNested::UTF8View& newValue) SWIFT_SYMBOL({{.*}});
 // CHECK:  SWIFT_INLINE_THUNK operator NSString * _Nonnull () const noexcept {
 // CHECK-NEXT:    return (__bridge_transfer NSString *)(_impl::$sSS10FoundationE19_bridgeToObjectiveCSo8NSStringCyF(_impl::swift_interop_passDirect_Swift_String(_getOpaquePointer())));
 // CHECK-NEXT:   }
@@ -118,13 +115,13 @@
 // CHECK-NEXT: private:
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) UTF8View final {
-// CHECK: SWIFT_INLINE_PRIVATE_HELPER UTF8View(UTF8View &&) noexcept {
+// CHECK: SWIFT_INLINE_THUNK UTF8View &operator =(const UTF8View &other) noexcept {
 // CHECK: }
-// CHECK-NEXT: SWIFT_INLINE_THUNK String_Index getStartIndex() const SWIFT_SYMBOL({{.*}});
-// CHECK-NEXT:   SWIFT_INLINE_THUNK String_Index getEndIndex() const SWIFT_SYMBOL({{.*}});
-// CHECK:   SWIFT_INLINE_THUNK swift::Optional<String_Index> indexOffsetByLimitedBy(const String_Index& i, swift::Int n, const String_Index& limit) const SWIFT_SYMBOL({{.*}});
-// CHECK:   SWIFT_INLINE_THUNK swift::Int distanceFromTo(const String_Index& i, const String_Index& j) const SWIFT_SYMBOL({{.*}});
-// CHECK: SWIFT_INLINE_THUNK uint8_t operator [](const String_Index& i) const SWIFT_SYMBOL({{.*}});
+// CHECK-NEXT: SWIFT_INLINE_THUNK __StringNested::Index getStartIndex() const SWIFT_SYMBOL({{.*}});
+// CHECK-NEXT:   SWIFT_INLINE_THUNK __StringNested::Index getEndIndex() const SWIFT_SYMBOL({{.*}});
+// CHECK:   SWIFT_INLINE_THUNK swift::Optional<__StringNested::Index> indexOffsetByLimitedBy(const __StringNested::Index& i, swift::Int n, const __StringNested::Index& limit) const SWIFT_SYMBOL({{.*}});
+// CHECK:   SWIFT_INLINE_THUNK swift::Int distanceFromTo(const __StringNested::Index& i, const __StringNested::Index& j) const SWIFT_SYMBOL({{.*}});
+// CHECK: SWIFT_INLINE_THUNK uint8_t operator [](const __StringNested::Index& i) const SWIFT_SYMBOL({{.*}});
 // CHECK:   SWIFT_INLINE_THUNK String getDescription() const SWIFT_SYMBOL({{.*}});
 // CHECK:   SWIFT_INLINE_THUNK swift::Int getCount() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT: private:
diff --git a/test/Interop/SwiftToCxx/structs/nested-structs-in-cxx.swift b/test/Interop/SwiftToCxx/structs/nested-structs-in-cxx.swift
index 47c17dd155baa..0b6c24cc577d1 100644
--- a/test/Interop/SwiftToCxx/structs/nested-structs-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/structs/nested-structs-in-cxx.swift
@@ -1,7 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -enable-library-evolution -module-name Structs -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/structs.h
-// RN: %FileCheck %s < %t/structs.h
+// RUN: %check-interop-cxx-header-in-clang(%t/structs.h -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY -std=c++17)
 
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -module-name Structs -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/structs.h
 // RUN: %check-interop-cxx-header-in-clang(%t/structs.h -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY -std=c++17)
 
 public enum AudioFileType {
@@ -66,3 +68,24 @@ public class TestObject {
         case invalid
     }
 }
+
+extension RecordConfig.File {
+    public func getFileExtension() -> String { ".wav" }
+}
+
+extension RecordConfig {
+    public struct NestedInExtension {
+        public var foo: Int
+    }
+}
+
+extension AudioFileType {
+    public struct NestedInExtension {
+        public var foo: Int
+    }
+}
+
+
+public func getFiles() -> [RecordConfig.File] {
+    []
+}
diff --git a/test/Interop/SwiftToCxx/structs/struct-move-semantics-in-cxx.cpp b/test/Interop/SwiftToCxx/structs/struct-move-semantics-in-cxx.cpp
index 5b88b84deb524..cb7c990d5c387 100644
--- a/test/Interop/SwiftToCxx/structs/struct-move-semantics-in-cxx.cpp
+++ b/test/Interop/SwiftToCxx/structs/struct-move-semantics-in-cxx.cpp
@@ -5,22 +5,19 @@
 // Link should fail by default when a move is
 // performed in C++.
 // RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-structs-execution.o
-// RUN: not %target-interop-build-swift %S/large-structs-pass-return-indirect-in-cxx.swift -o %t/swift-structs-execution -Xlinker %t/swift-structs-execution.o -module-name Structs -Xfrontend -entry-point-function-name -Xfrontend swiftMain 2>&1 | %FileCheck --check-prefix=LINK %s
-
-// LINK: fatalError_Cxx_move_of_Swift_value_type_not_supported_yet
+// RUN: %target-interop-build-swift %S/large-structs-pass-return-indirect-in-cxx.swift -o %t/swift-structs-execution -Xlinker %t/swift-structs-execution.o -module-name Structs -Xfrontend -entry-point-function-name -Xfrontend swiftMain 2>&1
 
 // Compile should fail by default when move assignment is attempted in C++:
 
-// RUN: not %target-interop-build-clangxx -c %s -I %t -o %t/swift-structs-execution.o -DMOVE_ASSIGN 2>&1 | %FileCheck --check-prefix=MOVEASSIGN %s
+// RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-structs-execution.o -DMOVE_ASSIGN 2>&1
 
 // Fallback to abort at runtime:
 
-// RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-structs-execution.o -DLINKS
+// RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-structs-execution.o
 // RUN: %target-interop-build-swift %S/large-structs-pass-return-indirect-in-cxx.swift -o %t/swift-structs-execution -Xlinker %t/swift-structs-execution.o -module-name Structs -Xfrontend -entry-point-function-name -Xfrontend swiftMain 2>&1
 
 // RUN: %target-codesign %t/swift-structs-execution
 // RUN: %target-run %t/swift-structs-execution 2>%t/output || true
-// RUN: cat %t/output  | %FileCheck %s
 
 // REQUIRES: executable_test
 
@@ -28,12 +25,6 @@
 #include "structs.h"
 #include <memory>
 
-#ifdef LINKS
-extern "C" void _fatalError_Cxx_move_of_Swift_value_type_not_supported_yet() {
-    
-}
-#endif
-
 int main() {
   using namespace Structs;
 
@@ -41,11 +32,8 @@ int main() {
 #ifdef MOVE_ASSIGN
   auto y = returnNewStructSeveralI64(24);
   x = std::move(y);
-// MOVEASSIGN: deleted operator '='
 #else
   StructSeveralI64 x2 = std::move(x);
 #endif
   return 0;
 }
-
-// CHECK: C++ does not support moving a Swift value yet
diff --git a/test/Interop/SwiftToCxx/structs/struct-with-refcounted-member.swift b/test/Interop/SwiftToCxx/structs/struct-with-refcounted-member.swift
index 4744b891d178c..7da729e54e740 100644
--- a/test/Interop/SwiftToCxx/structs/struct-with-refcounted-member.swift
+++ b/test/Interop/SwiftToCxx/structs/struct-with-refcounted-member.swift
@@ -58,10 +58,4 @@ public func printBreak(_ x: Int) {
 // CHECK-NEXT:     vwTable->assignWithCopy(_getOpaquePointer(), const_cast<char *>(other._getOpaquePointer()), metadata._0);
 // CHECK-NEXT:   return *this;
 // CHECK-NEXT:   }
-// CHECK-NEXT:   SWIFT_INLINE_THUNK StructWithRefcountedMember &operator =(StructWithRefcountedMember &&other) = delete;
-// CHECK-NEXT:   SWIFT_INLINE_PRIVATE_HELPER StructWithRefcountedMember(StructWithRefcountedMember &&) noexcept {
-// CHECK-NEXT:  swift::_impl::_fatalError_Cxx_move_of_Swift_value_type_not_supported_yet();
-// CHECK-NEXT:  swift::_impl::_swift_stdlib_reportFatalError("swift", 5, "C++ does not support moving a Swift value yet", 45, 0);
-// CHECK-NEXT:  abort();
-// CHECK-NEXT: }
 // CHECK-NEXT: private:
diff --git a/test/Interop/SwiftToCxx/structs/swift-struct-in-cxx.swift b/test/Interop/SwiftToCxx/structs/swift-struct-in-cxx.swift
index 9d12392e8c394..4ac4c4c667936 100644
--- a/test/Interop/SwiftToCxx/structs/swift-struct-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/structs/swift-struct-in-cxx.swift
@@ -49,12 +49,6 @@
 // CHECK-NEXT:     vwTable->assignWithCopy(_getOpaquePointer(), const_cast<char *>(other._getOpaquePointer()), metadata._0);
 // CHECK-NEXT:   return *this;
 // CHECK-NEXT:  }
-// CHECK-NEXT:   SWIFT_INLINE_THUNK StructWithIntField &operator =(StructWithIntField &&other) = delete;
-// CHECK-NEXT:   noreturn]] SWIFT_INLINE_PRIVATE_HELPER StructWithIntField(StructWithIntField &&) noexcept {
-// CHECK-NEXT:   swift::_impl::_fatalError_Cxx_move_of_Swift_value_type_not_supported_yet();
-// CHECK-NEXT:   swift::_impl::_swift_stdlib_reportFatalError("swift", 5, "C++ does not support moving a Swift value yet", 45, 0);
-// CHECK-NEXT:   abort();
-// CHECK-NEXT:   }
 // CHECK-NEXT: private:
 // CHECK-NEXT:   SWIFT_INLINE_THUNK StructWithIntField() noexcept {}
 // CHECK-NEXT:   static SWIFT_INLINE_THUNK StructWithIntField _make() noexcept { return StructWithIntField(); }
diff --git a/test/Interop/SwiftToCxx/unsupported/unsupported-objc-decls-in-cxx.swift b/test/Interop/SwiftToCxx/unsupported/unsupported-objc-decls-in-cxx.swift
index dac74ba887685..fbb92338f2b60 100644
--- a/test/Interop/SwiftToCxx/unsupported/unsupported-objc-decls-in-cxx.swift
+++ b/test/Interop/SwiftToCxx/unsupported/unsupported-objc-decls-in-cxx.swift
@@ -15,7 +15,7 @@ import Foundation
 public func supported() {}
 
 @objc
-@_expose(Cxx) // expected-error {{@objc class 'UnsupportedClass' can not yet be exposed to C++}}
+@_expose(Cxx) // expected-error {{'@objc' class 'UnsupportedClass' can not yet be exposed to C++}}
 public class UnsupportedClass: NSObject {
     override public init() {
         x = 0
diff --git a/test/Interop/lit.local.cfg b/test/Interop/lit.local.cfg
index 26efb7ec1ea2a..65e4f12046386 100644
--- a/test/Interop/lit.local.cfg
+++ b/test/Interop/lit.local.cfg
@@ -50,7 +50,7 @@ if get_target_os() in ['linux-gnu']:
 
 # Enable C++ interop when compiling Swift sources.
 config.substitutions.insert(0, ('%target-interop-build-swift',
-                                '%target-build-swift -Xfrontend -enable-experimental-cxx-interop '))
+                                '%target-build-swift -cxx-interoperability-mode=default '))
 
 # Build C files disallowing implicit functions and with matching link settings, if required by the target.
 config.substitutions.insert(0, ('%target-interop-build-clang',  '%target-clang -x c -Werror=implicit-function-declaration ' + clang_opt))
@@ -65,6 +65,12 @@ config.substitutions.insert(0, (r'%check-interop-cxx-header-in-clang\(([^)]+)\)'
                                                 r'%check-cxx-header-in-clang -std=c++20 -Wno-padded -Wno-c11-extensions -D_LIBCPP_CSTDLIB ' + clang_compile_opt + r'\1')))
 
 # Test parsing of the generated C header in different C language modes.
-config.substitutions.insert(0, (r'%check-interop-c-header-in-clang\(([^)]+)\)',
-                             SubstituteCaptures(r'%check-c-header-in-clang -std=c99 -Wno-padded -Wno-c11-extensions -Wno-pre-c11-compat \1 && '
-                                                r'%check-c-header-in-clang -std=c11 -Wno-padded -Wno-pre-c11-compat \1')))
+config.substitutions.insert(0, (
+    r'%check-interop-c-header-in-clang\(([^)]+)\)',
+    SubstituteCaptures(
+        r'%check-c-header-in-clang -std=c99 -Wno-padded -Wno-c++-keyword -Wno-unknown-warning-option -Wno-c11-extensions -Wno-pre-c11-compat \1 && '
+        r'%check-c-header-in-clang -std=c11 -Wno-padded -Wno-c++-keyword -Wno-unknown-warning-option -Wno-pre-c11-compat \1'
+    )
+))
+
+config.substitutions.insert(0, ('%bridging-path', '%swift_src_root%{fs-sep}lib%{fs-sep}ClangImporter%{fs-sep}SwiftBridging'))
diff --git a/test/Interpreter/Inputs/layout_string_witnesses_types.swift b/test/Interpreter/Inputs/layout_string_witnesses_types.swift
index 65060bfb66c72..306573c1a4533 100644
--- a/test/Interpreter/Inputs/layout_string_witnesses_types.swift
+++ b/test/Interpreter/Inputs/layout_string_witnesses_types.swift
@@ -341,11 +341,13 @@ public struct NestedWrapper<T> {
     }
 }
 
-struct InternalGeneric<T> {
+struct InternalGeneric<T: ~Copyable>: ~Copyable {
     let y: Int
     let x: T
 }
 
+extension InternalGeneric: Copyable where T: Copyable {}
+
 public enum SinglePayloadSimpleClassEnum {
     case empty0
     case empty1
@@ -673,6 +675,21 @@ public enum MultiPayloadAnyObject {
     case z(AnyObject)
 }
 
+public struct NonCopyableGenericStruct<T>: ~Copyable {
+    let x: Int
+    let y: T
+
+    public init(x: Int, y: T) {
+        self.x = x
+        self.y = y
+    }
+}
+
+public enum NonCopyableGenericEnum<T>: ~Copyable {
+    case x(Int, T?)
+    case y(Int)
+}
+
 @inline(never)
 public func consume<T>(_ x: T.Type) {
     withExtendedLifetime(x) {}
@@ -696,7 +713,7 @@ public func preSpec() {
 }
 
 @inline(never)
-public func testAssign<T>(_ ptr: UnsafeMutablePointer<T>, from x: T) {
+public func testAssign<T: ~Copyable>(_ ptr: UnsafeMutablePointer<T>, from x: consuming T) {
     ptr.pointee = x
 }
 
@@ -706,7 +723,7 @@ public func testAssignCopy<T>(_ ptr: UnsafeMutablePointer<T>, from x: inout T) {
 }
 
 @inline(never)
-public func testInit<T>(_ ptr: UnsafeMutablePointer<T>, to x: T) {
+public func testInit<T: ~Copyable>(_ ptr: UnsafeMutablePointer<T>, to x: consuming T) {
     ptr.initialize(to: x)
 }
 
@@ -716,32 +733,32 @@ public func testInitTake<T>(_ ptr: UnsafeMutablePointer<T>, to x: consuming T) {
 }
 
 @inline(never)
-public func testDestroy<T>(_ ptr: UnsafeMutablePointer<T>) {
+public func testDestroy<T: ~Copyable>(_ ptr: UnsafeMutablePointer<T>) {
     _ = ptr.move()
 }
 
 @inline(never)
-public func allocateInternalGenericPtr<T>(of tpe: T.Type) -> UnsafeMutableRawPointer {
+public func allocateInternalGenericPtr<T: ~Copyable>(of tpe: T.Type) -> UnsafeMutableRawPointer {
     return UnsafeMutableRawPointer(
         UnsafeMutablePointer<InternalGeneric<T>>.allocate(capacity: 1))
 }
 
 @inline(never)
-public func testGenericAssign<T>(_ ptr: __owned UnsafeMutableRawPointer, from x: T) {
+public func testGenericAssign<T: ~Copyable>(_ ptr: __owned UnsafeMutableRawPointer, from x: consuming T) {
     let ptr = ptr.assumingMemoryBound(to: InternalGeneric<T>.self)
     let x = InternalGeneric(y: 23, x: x)
     testAssign(ptr, from: x)
 }
 
 @inline(never)
-public func testGenericInit<T>(_ ptr: __owned UnsafeMutableRawPointer, to x: T) {
+public func testGenericInit<T: ~Copyable>(_ ptr: __owned UnsafeMutableRawPointer, to x: consuming T) {
     let ptr = ptr.assumingMemoryBound(to: InternalGeneric<T>.self)
     let x = InternalGeneric(y: 23, x: x)
     testInit(ptr, to: x)
 }
 
 @inline(never)
-public func testGenericDestroy<T>(_ ptr: __owned UnsafeMutableRawPointer, of tpe: T.Type) {
+public func testGenericDestroy<T: ~Copyable>(_ ptr: __owned UnsafeMutableRawPointer, of tpe: T.Type) {
     let ptr = ptr.assumingMemoryBound(to: InternalGeneric<T>.self)
     testDestroy(ptr)
 }
@@ -751,6 +768,11 @@ public func testGenericArrayDestroy<T>(_ buffer: UnsafeMutableBufferPointer<T>)
     buffer.deinitialize()
 }
 
+@inline(never)
+public func testGenericArrayDestroy<T: ~Copyable>(_ buffer: UnsafeMutableBufferPointer<T>) {
+    buffer.deinitialize()
+}
+
 @inline(never)
 public func testGenericArrayInitWithCopy<T>(dest: UnsafeMutableBufferPointer<T>, src: UnsafeMutableBufferPointer<T>) {
     _ = dest.initialize(fromContentsOf: src)
diff --git a/test/Interpreter/SDK/GLKit.swift b/test/Interpreter/SDK/GLKit.swift
index a689625fbbdb5..1a37fff7280d2 100644
--- a/test/Interpreter/SDK/GLKit.swift
+++ b/test/Interpreter/SDK/GLKit.swift
@@ -1,4 +1,5 @@
-// RUN: %target-run-simple-swift | %FileCheck %s
+// RUN: %empty-directory(%t/cache)
+// RUN: %target-run-simple-swift(-module-cache-path %t/cache) | %FileCheck %s
 // REQUIRES: executable_test
 
 // NOTE: Clang used to miscompile GLKit functions on i386. rdar://problem/19184403
diff --git a/test/Interpreter/SDK/cf_extensions.swift b/test/Interpreter/SDK/cf_extensions.swift
index 91d37d5149796..d95b8d9ddcb16 100644
--- a/test/Interpreter/SDK/cf_extensions.swift
+++ b/test/Interpreter/SDK/cf_extensions.swift
@@ -1,4 +1,5 @@
-// RUN: %target-run-simple-swift
+// RUN: %empty-directory(%t/cache)
+// RUN: %target-run-simple-swift(-module-cache-path %t/cache)
 // REQUIRES: executable_test
 
 // REQUIRES: objc_interop
diff --git a/test/Interpreter/SDK/cf_type_bridging.swift b/test/Interpreter/SDK/cf_type_bridging.swift
index 6b592464ba735..839355b7388ba 100644
--- a/test/Interpreter/SDK/cf_type_bridging.swift
+++ b/test/Interpreter/SDK/cf_type_bridging.swift
@@ -1,4 +1,5 @@
-// RUN: %target-run-simple-swift
+// RUN: %empty-directory(%t/cache)
+// RUN: %target-run-simple-swift(-module-cache-path %t/cache)
 // REQUIRES: executable_test
 
 // REQUIRES: objc_interop
diff --git a/test/Interpreter/SDK/mapkit_header_static.swift b/test/Interpreter/SDK/mapkit_header_static.swift
index 30fdb06bfcd2f..46af5f4dfa5fc 100644
--- a/test/Interpreter/SDK/mapkit_header_static.swift
+++ b/test/Interpreter/SDK/mapkit_header_static.swift
@@ -1,4 +1,5 @@
-// RUN: %target-run-simple-swift | %FileCheck %s
+// RUN: %empty-directory(%t/cache)
+// RUN: %target-run-simple-swift(-module-cache-path %t/cache) | %FileCheck %s
 // REQUIRES: executable_test
 
 // REQUIRES: objc_interop
diff --git a/test/Interpreter/SDK/misc_osx.swift b/test/Interpreter/SDK/misc_osx.swift
index 15383cf784077..4b6b747c90693 100644
--- a/test/Interpreter/SDK/misc_osx.swift
+++ b/test/Interpreter/SDK/misc_osx.swift
@@ -1,4 +1,4 @@
-// RUN: %target-build-swift -typecheck %s -Xfrontend -verify
+// RUN: %target-build-swift -typecheck %s -Xfrontend -verify -Xfrontend -verify-ignore-unrelated
 // REQUIRES: executable_test
 // REQUIRES: OS=macosx
 
diff --git a/test/Interpreter/SDK/objc_getClass.swift b/test/Interpreter/SDK/objc_getClass.swift
index 945771d24819b..109458b095fc2 100644
--- a/test/Interpreter/SDK/objc_getClass.swift
+++ b/test/Interpreter/SDK/objc_getClass.swift
@@ -256,17 +256,25 @@ testSuite.test("NotPresent") {
   // Swift.Int is not a class type.
   expectNil(NSClassFromString("Si"))
 
-  // Mangled names with byte sequences that look like symbolic references
-  // should not be demangled.
-  expectNil(NSClassFromString("\u{1}badnews"));
-  expectNil(NSClassFromString("$s\u{1}badnews"));
-  expectNil(NSClassFromString("_T\u{1}badnews"));
-
-  // Correct mangled names with additional text afterwards should not resolve.
-  expectNil(NSClassFromString("_TtC4main20MangledSwiftSubclass_"))
-  expectNil(NSClassFromString("_TtC4main22MangledSwiftSuperclassXYZ"))
-  expectNil(NSClassFromString("_TtC4main19MangledObjCSubclass123"))
-  expectNil(NSClassFromString("_TtC4main21MangledObjCSuperclasswhee"))
+  if #available(StdlibDeploymentTarget 5.3, *) {
+    // Mangled names with byte sequences that look like symbolic references
+    // should not be demangled. Use indirect references to test. Direct
+    // references often resolve to readable memory, and then the data there
+    // often looks like a descriptor with an unknown kind and the lookup code
+    // then fails gracefully. With an indirect reference, the indirected pointer
+    // is typically garbage and dereferencing it will crash.
+    expectNil(NSClassFromString("\u{2}badnews"));
+    expectNil(NSClassFromString("$s\u{2}badnews"));
+    expectNil(NSClassFromString("_T\u{2}badnews"));
+  }
+
+  if #available(StdlibDeploymentTarget 5.3, *) {
+    // Correct mangled names with additional text afterwards should not resolve.
+    expectNil(NSClassFromString("_TtC4main20MangledSwiftSubclass_"))
+    expectNil(NSClassFromString("_TtC4main22MangledSwiftSuperclassXYZ"))
+    expectNil(NSClassFromString("_TtC4main19MangledObjCSubclass123"))
+    expectNil(NSClassFromString("_TtC4main21MangledObjCSuperclasswhee"))
+  }
 }
 
 runAllTests()
diff --git a/test/Interpreter/SDK/objc_ns_enum.swift b/test/Interpreter/SDK/objc_ns_enum.swift
index 44624f3b39a5d..540cb5da13fdd 100644
--- a/test/Interpreter/SDK/objc_ns_enum.swift
+++ b/test/Interpreter/SDK/objc_ns_enum.swift
@@ -1,4 +1,5 @@
-// RUN: %target-run-simple-swift
+// RUN: %empty-directory(%t/cache)
+// RUN: %target-run-simple-swift(-module-cache-path %t/cache)
 // REQUIRES: executable_test
 
 // NSButtonType (from AppKit) and UIViewAnimationCurve (from UIKit) both have
diff --git a/test/Interpreter/bridged_casts_folding.swift b/test/Interpreter/bridged_casts_folding.swift
index 7fe9f52fab4a3..afb9731c46c24 100644
--- a/test/Interpreter/bridged_casts_folding.swift
+++ b/test/Interpreter/bridged_casts_folding.swift
@@ -58,7 +58,7 @@ Tests.test("NSString => Array<Int>. Crashing test case") {
   // CHECK: [       OK ] BridgedCastFolding.NSString => Array<Int>. Crashing test case
 
   // CHECK-OPT-LABEL: [ RUN      ] BridgedCastFolding.NSString => Array<Int>. Crashing test case
-  // CHECK-OPT: stderr>>> OK: saw expected "crashed: sig{{ill|trap}}"
+  // CHECK-OPT: stderr>>> OK: saw expected "crashed: sigabrt"
   // CHECK-OPT: [       OK ] BridgedCastFolding.NSString => Array<Int>. Crashing test case
   expectCrashLater()
   do {
@@ -130,7 +130,7 @@ Tests.test("NSNumber (Int) -> String. Crashing test.") {
   // CHECK: [       OK ] BridgedCastFolding.NSNumber (Int) -> String. Crashing test.
 
   // CHECK-OPT-LABEL: [ RUN      ] BridgedCastFolding.NSNumber (Int) -> String. Crashing test.
-  // CHECK-OPT: stderr>>> OK: saw expected "crashed: sig{{ill|trap}}"
+  // CHECK-OPT: stderr>>> OK: saw expected "crashed: sigabrt"
   // CHECK-OPT: [       OK ] BridgedCastFolding.NSNumber (Int) -> String. Crashing test.
   expectCrashLater()
   do {
@@ -393,7 +393,7 @@ Tests.test("String -> NSNumber. Crashing Test Case") {
   // CHECK: [       OK ] BridgedCastFolding.String -> NSNumber. Crashing Test Case
 
   // CHECK-OPT-LABEL: [ RUN      ] BridgedCastFolding.String -> NSNumber. Crashing Test Case
-  // CHECK-OPT: stderr>>> OK: saw expected "crashed: sig{{ill|trap}}"
+  // CHECK-OPT: stderr>>> OK: saw expected "crashed: sigabrt"
   // CHECK-OPT: [       OK ] BridgedCastFolding.String -> NSNumber. Crashing Test Case
   expectCrashLater()
   do {
diff --git a/test/Interpreter/builtin_bridge_object.swift b/test/Interpreter/builtin_bridge_object.swift
index 92f933f94abe1..6cf1b6b2b37cd 100644
--- a/test/Interpreter/builtin_bridge_object.swift
+++ b/test/Interpreter/builtin_bridge_object.swift
@@ -3,6 +3,8 @@
 
 // REQUIRES: executable_test
 // REQUIRES: objc_interop
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
 // rdar://124700033
 // UNSUPPORTED: OS=xros
 
diff --git a/test/Interpreter/cdecl_enum_run.swift b/test/Interpreter/cdecl_enum_run.swift
new file mode 100644
index 0000000000000..4b1af86b6f3a8
--- /dev/null
+++ b/test/Interpreter/cdecl_enum_run.swift
@@ -0,0 +1,45 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature CDecl) > %t.out
+// RUN: %FileCheck --input-file %t.out %s
+
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: executable_test
+
+@c
+enum CDecl8: UInt8 {
+case a
+case b
+}
+
+@c
+enum CDecl16: UInt16 {
+case a
+case b
+}
+
+@c(SomeName)
+enum CDecl32: UInt32 {
+case a
+case b
+}
+
+@objc
+enum ObjCEnum: UInt32 {
+case a
+case b
+}
+
+enum SwiftEnum: Int32 {
+case a
+case b
+}
+
+print("@c enum 8 is \(MemoryLayout<CDecl8>.size) bytes")
+// CHECK: @c enum 8 is 1 bytes
+print("@c enum 16 is \(MemoryLayout<CDecl16>.size) bytes")
+// CHECK: @c enum 16 is 2 bytes
+print("@c enum 32 is \(MemoryLayout<CDecl32>.size) bytes")
+// CHECK: @c enum 32 is 4 bytes
+print("@objc enum is \(MemoryLayout<ObjCEnum>.size) bytes")
+// CHECK: @objc enum is 4 bytes
+print("Swift enum is \(MemoryLayout<SwiftEnum>.size) bytes")
+// CHECK: Swift enum is 1 bytes
diff --git a/test/Interpreter/cdecl_implementation_run.swift b/test/Interpreter/cdecl_implementation_run.swift
new file mode 100644
index 0000000000000..bb0e889fbbcaf
--- /dev/null
+++ b/test/Interpreter/cdecl_implementation_run.swift
@@ -0,0 +1,94 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t --leading-lines
+
+/// Build Swift dylib and compatibility header.
+// RUN: %target-build-swift-dylib(%t/%target-library-name(Lib)) %t/Lib.swift \
+// RUN:   -emit-module-path %t/Lib.swiftmodule \
+// RUN:   -emit-clang-header-path %t/cdecl.h \
+// RUN:   -import-objc-header %t/BridgingHeader.h \
+// RUN:   -enable-experimental-feature CDecl \
+// RUN:   -enable-experimental-feature CImplementation
+// RUN: %target-codesign %t/%target-library-name(Lib)
+
+/// Build a C client against cdecl.h.
+// RUN: %clang-no-modules %t/Client.c -o %t/a.out -target %target-triple \
+// RUN:   -I %clang-include-dir -Werror -isysroot %sdk \
+// RUN:   -I %t -l Lib -L %t %target-rpath(%t)
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out %t/%target-library-name(Lib) > %t/run.log
+// RUN: %FileCheck %t/Client.c --check-prefix=PRINTS --input-file %t/run.log
+
+/// Build a Swift client against cdecl.h.
+// RUN: %target-build-swift %t/Client.swift -o %t/a.out \
+// RUN:   -I %t -l Lib -L %t %target-rpath(%t)
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out %t/%target-library-name(Lib) > %t/run.log
+// RUN: %FileCheck %t/Client.swift --check-prefix=PRINTS --input-file %t/run.log
+
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: swift_feature_CImplementation
+// REQUIRES: executable_test
+
+//--- BridgingHeader.h
+#include <stddef.h>
+#include <stdbool.h>
+
+extern int simple(int x, int y);
+
+extern void primitiveTypes(ptrdiff_t i, int ci, long l, char c, float f, double d, bool b);
+
+extern void sameName();
+
+__attribute__((swift_name("renamed_swiftSide(_:)")))
+extern void renamed_clangSide(ptrdiff_t arg);
+
+//--- Lib.swift
+
+@c @implementation
+public func simple(_ x: Int32, _ y: Int32) -> Int32 {
+    print(x, y)
+    return x
+}
+
+@implementation @c
+public func primitiveTypes(_ i: Int, _ ci: CInt, _ l: CLong, _ c: CChar, _ f: Float, _ d: Double, _ b: Bool) {
+    print(i, ci, l, c, f, d, b)
+}
+
+@c(sameName) @implementation
+public func sameName() {
+    print("sameName")
+}
+
+@c(renamed_clangSide) @implementation
+public func renamed_swiftSide(_ arg: Int) {
+    print(arg)
+}
+
+//--- Client.c
+
+#include "cdecl.h"
+#include "BridgingHeader.h"
+
+int main() {
+    ptrdiff_t x = simple(42, 43);
+    // PRINTS: 42 43
+    primitiveTypes(1, 2, 3, 'a', 1.0f, 2.0, true);
+    // PRINTS: 1 2 3 97 1.0 2.0 true
+    sameName();
+    // PRINTS: sameName
+    renamed_clangSide(11);
+    // PRINTS: 11
+}
+
+//--- Client.swift
+import Lib
+
+let _ = simple(42, 43)
+// PRINTS: 42 43
+primitiveTypes(1, 2, 3, 97, 1.0, 2.0, true)
+// PRINTS: 1 2 3 97 1.0 2.0 true
+sameName();
+// PRINTS: sameName
+renamed_swiftSide(11)
+// PRINTS: 11
diff --git a/test/Interpreter/cdecl_official_run.swift b/test/Interpreter/cdecl_official_run.swift
new file mode 100644
index 0000000000000..52fbc2262d1c6
--- /dev/null
+++ b/test/Interpreter/cdecl_official_run.swift
@@ -0,0 +1,78 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t --leading-lines
+
+/// Generate an internal cdecl.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   %t/Lib.swift -emit-module -verify -o %t -emit-module-doc \
+// RUN:   -emit-clang-header-path %t/cdecl.h \
+// RUN:   -disable-implicit-string-processing-module-import \
+// RUN:   -disable-implicit-concurrency-module-import \
+// RUN:   -enable-experimental-feature CDecl
+
+/// Build and run a binary from Swift and C code.
+// RUN: %clang-no-modules -c %t/Client.c -o %t/Client.o -target %target-triple \
+// RUN:   %target-pic-opt -I %t -I %clang-include-dir -Werror -isysroot %sdk
+// RUN: %target-build-swift %t/Lib.swift %t/Client.o -O -o %t/a.out \
+// RUN:   -Xfrontend -disable-implicit-string-processing-module-import \
+// RUN:   -Xfrontend -disable-implicit-concurrency-module-import \
+// RUN:   -enable-experimental-feature CDecl -parse-as-library
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out > %t/run.log
+// RUN: %FileCheck %s --input-file %t/run.log
+
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: executable_test
+
+//--- Lib.swift
+
+/// My documentation
+@c(simple) public func simpleNameSwiftSide(x: CInt, bar y: CInt) -> CInt {
+    print(x, y)
+    return x
+}
+
+@c func defaultName(x: Int) {
+    print(x)
+}
+
+@c public func primitiveTypes(i: Int, ci: CInt, l: CLong, c: CChar, f: Float, d: Double, b: Bool) {
+    print(i, ci, l, c, f, d, b)
+}
+
+@c enum CEnum: CInt { case A, B }
+
+@c func useEnum(e: CEnum) -> CEnum {
+    print(e)
+    print(e.rawValue)
+    return e
+}
+
+//--- Client.c
+
+#include <stdio.h>
+#include "cdecl.h"
+
+int main() {
+    int x = simple(42, 43);
+    // CHECK: 42 43
+    printf("%d\n", x);
+    // CHECK-NEXT: 42
+
+    defaultName(121);
+    // CHECK-NEXT: 121
+
+    primitiveTypes(1, 2, 3, 'a', 1.0f, 2.0, true);
+    // CHECK-NEXT: 1 2 3 97 1.0 2.0 true
+
+    CEnum a = useEnum(CEnumA);
+    // CHECK-NEXT: CEnum
+    // CHECK-NEXT: 0
+    printf("%d\n", a);
+    // CHECK-NEXT: 0
+
+    CEnum b = useEnum(CEnumB);
+    // CHECK-NEXT: CEnum
+    // CHECK-NEXT: 1
+    printf("%d\n", b);
+    // CHECK-NEXT: 1
+}
diff --git a/test/Interpreter/consume_operator_kills_copyable_values.swift.gyb b/test/Interpreter/consume_operator_kills_copyable_values.swift.gyb
index f902315127084..dab83c3d17cf1 100644
--- a/test/Interpreter/consume_operator_kills_copyable_values.swift.gyb
+++ b/test/Interpreter/consume_operator_kills_copyable_values.swift.gyb
@@ -176,6 +176,20 @@ func testNested2_${introducer}(_ c1: Bool, _ c2: Bool) {
   end([c1, c2])
 }
 
+// CHECK-LABEL: begin testDeadEnd_{{let|var}}(_:)(true)
+// CHECK:       hi
+// CHECK:       adios
+// CHECK:       barrier
+// CHECK-LABEL: end testDeadEnd_{{let|var}}(_:)(true)
+func testDeadEnd_${introducer}(_ condition: Bool) {
+  begin([condition])
+  ${introducer} x = X(0)
+  _ = consume x
+  guard condition else { fatalError() }
+  barrier()
+  end([condition])
+}
+
 func main_${introducer}() {
   simple_${introducer}()
   testLeft_${introducer}(true)
@@ -188,6 +202,7 @@ func main_${introducer}() {
   testNested2_${introducer}(false, true)
   testNested2_${introducer}(true, false)
   testNested2_${introducer}(true, true)
+  testDeadEnd_${introducer}(true)
 }
 
 % end
diff --git a/test/Interpreter/coroutine_accessors_default_implementations.swift b/test/Interpreter/coroutine_accessors_default_implementations.swift
index a75e06e64794f..ecd7b2bb97354 100644
--- a/test/Interpreter/coroutine_accessors_default_implementations.swift
+++ b/test/Interpreter/coroutine_accessors_default_implementations.swift
@@ -5,6 +5,7 @@
 // RUN: %target-swift-frontend \
 // RUN:     %t/Library.swift   \
 // RUN:     %t/LibImpl.underscored.swift   \
+// RUN:     -enable-callee-allocated-coro-abi \
 // RUN:     -emit-module       \
 // RUN:     -module-name Library \
 // RUN:     -parse-as-library  \
@@ -13,6 +14,7 @@
 
 // RUN: %target-swift-frontend \
 // RUN:     %t/Executable.swift \
+// RUN:     -enable-callee-allocated-coro-abi \
 // RUN:     -c \
 // RUN:     -parse-as-library \
 // RUN:     -module-name Executable \
@@ -22,6 +24,7 @@
 // RUN: %target-build-swift-dylib(%t/%target-library-name(Library)) \
 // RUN:     %t/Library.swift \
 // RUN:     %t/LibImpl.nonunderscored.swift   \
+// RUN:     -Xfrontend -enable-callee-allocated-coro-abi \
 // RUN:     -emit-module \
 // RUN:     -enable-library-evolution \
 // RUN:     -enable-experimental-feature CoroutineAccessors \
@@ -35,13 +38,17 @@
 // RUN:     %target-rpath(%t) \
 // RUN:     -o %t/main
 
-// RUN: %target-codesign %t/%target-library-name(Library)
-// RUN: %target-codesign %t/main
+// RUN: %target-codesign %t/main %t/%target-library-name(Library)
 // RUN: %target-run %t/main %t/%target-library-name(Library) | %FileCheck %s
 
 // REQUIRES: swift_feature_CoroutineAccessors
 // REQUIRES: executable_test
 
+// This test verifies the backwards compatibility of binaries built against old
+// SDKs running on newer OSes (where CoroutineAccessors has been enabled).
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
 //--- Library.swift
 public protocol P {
   @_borrowed
diff --git a/test/Interpreter/coroutine_accessors_old_abi_nounwind.swift b/test/Interpreter/coroutine_accessors_old_abi_nounwind.swift
new file mode 100644
index 0000000000000..79cad8f0a3c8e
--- /dev/null
+++ b/test/Interpreter/coroutine_accessors_old_abi_nounwind.swift
@@ -0,0 +1,41 @@
+// RUN: %target-run-simple-swift(-Xfrontend -disable-callee-allocated-coro-abi -enable-experimental-feature CoroutineAccessors) | %FileCheck %s
+
+// REQUIRES: swift_feature_CoroutineAccessors
+// REQUIRES: executable_test
+
+struct AirOr : Error {
+}
+
+struct Thrower {
+  mutating func doit() throws {
+    throw AirOr()
+  }
+}
+
+struct S {
+  var _thrower = Thrower()
+  var thrower: Thrower {
+    read {
+      yield _thrower
+    }
+    modify {
+      // CHECK: first
+      print("first")
+      yield &_thrower
+      // CHECK: also ran
+      print("also ran")
+    }
+  }
+}
+
+func doit() {
+  do {
+    var s = S()
+    try s.thrower.doit()
+  } catch let error {
+    // CHECK: AirOr
+    print(error)
+  }
+}
+
+doit()
diff --git a/test/Interpreter/enum.swift b/test/Interpreter/enum.swift
index 7746ea218ca61..1995cc8078cec 100644
--- a/test/Interpreter/enum.swift
+++ b/test/Interpreter/enum.swift
@@ -745,3 +745,45 @@ func reproduction<T: Init>(_ x: Int, _ y: Int, _ t: T) {
 
 // CHECK: there is no byte
 reproduction(2, 3, TrailingByte())
+
+do {
+  // regression test for https://github.com/swiftlang/swift-driver/pull/1987
+  @inline(never) func blackhole<T>(_ t: T) { }
+
+  final class Context {
+    func doSomething() {}
+    deinit {
+      print("Context deinit")
+    }
+  }
+
+  enum MyOptional<Value> {
+    case some(Value)
+    case none
+  }
+
+  final class _GenericStorage<Value> {
+    let value: MyOptional<Value>
+
+    init(value: Value) {
+      self.value = .some(value)
+    }
+
+    func unwrapAndCopy() {
+      if case .some(let value) = value {
+        blackhole(value)
+      }
+    }
+  }
+
+  let test = _GenericStorage(
+    value: Context().doSomething,
+  )
+  // CHECK: test.unwrapAndCopy
+  print("test.unwrapAndCopy")
+  test.unwrapAndCopy()
+  // CHECK: test.unwrapAndCopy
+  print("test.unwrapAndCopy")
+  test.unwrapAndCopy()
+  // CHECK: Context deinit
+}
diff --git a/test/Interpreter/extended_existential.swift b/test/Interpreter/extended_existential.swift
new file mode 100644
index 0000000000000..8098db72d8341
--- /dev/null
+++ b/test/Interpreter/extended_existential.swift
@@ -0,0 +1,51 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift -O -target %target-cpu-apple-macos15.0 %s -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+// REQUIRES: OS=macosx
+// REQUIRES: executable_test
+
+protocol A<B>: ~Copyable {
+  associatedtype B
+}
+
+protocol B: ~Copyable {}
+
+let a: Any = (any ~Copyable).self
+// CHECK: any Any<Self: ~Swift.Copyable>
+print(a)
+
+let b: Any = (any ~Escapable).self
+// CHECK: any Any<Self: ~Swift.Escapable>
+print(b)
+
+let c: Any = (any ~Copyable & ~Escapable).self
+// CHECK: any Any<Self: ~Swift.Copyable, Self: ~Swift.Escapable>
+print(c)
+
+let d: Any = (any A).self
+// CHECK: A
+print(d)
+
+let e: Any = (any B).self
+// CHECK: B
+print(e)
+
+let f: Any = (any A & B).self
+// CHECK: A & B
+print(f)
+
+let g: Any = (any A & ~Copyable).self
+// CHECK: any A<Self: ~Swift.Copyable>
+print(g)
+
+let h: Any = (any B & ~Copyable).self
+// CHECK: any B<Self: ~Swift.Copyable>
+print(h)
+
+let i: Any = (any A & B & ~Copyable).self
+// CHECK: any A & B<Self: ~Swift.Copyable>
+print(i)
diff --git a/test/Interpreter/inline_array_enum_tags.swift b/test/Interpreter/inline_array_enum_tags.swift
new file mode 100644
index 0000000000000..32fc9493663c0
--- /dev/null
+++ b/test/Interpreter/inline_array_enum_tags.swift
@@ -0,0 +1,35 @@
+// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking) | %FileCheck %s
+// RUN: %target-run-simple-swift(-O -Xfrontend -disable-availability-checking) | %FileCheck %s
+
+// REQUIRES: executable_test
+
+// UNSUPPORTED: back_deployment_runtime || use_os_stdlib
+
+struct Foo {
+    let x: UInt64
+    let y: InlineArray<2, UInt64>
+}
+
+struct Bar {
+    let x: UInt64
+    let y: [UInt64]
+}
+
+enum Baz {
+    case foo(Foo)
+    case bar(Bar)
+}
+
+@inline(never)
+func createEnum() -> Baz {
+    return .foo(Foo(x: 0, y: [0, 0xff00000000000000]))
+}
+
+
+let x = createEnum()
+
+// CHECK: 0 - 18374686479671623680
+switch x {
+    case .bar: fatalError("Expected .foo")
+    case .foo(let x): print("\(x.y[0]) - \(x.y[1])")
+}
diff --git a/test/Interpreter/layout_string_witnesses_dynamic.swift b/test/Interpreter/layout_string_witnesses_dynamic.swift
index 418ebbabfc064..f4dc2497cf374 100644
--- a/test/Interpreter/layout_string_witnesses_dynamic.swift
+++ b/test/Interpreter/layout_string_witnesses_dynamic.swift
@@ -4,7 +4,7 @@
 // RUN: %target-codesign %t/%target-library-name(layout_string_witnesses_types)
 // RUN: %target-swift-frontend -target %target-future-triple -enable-experimental-feature LayoutStringValueWitnesses -enable-experimental-feature LayoutStringValueWitnessesInstantiation -enable-layout-string-value-witnesses -enable-layout-string-value-witnesses-instantiation -enable-library-evolution -enable-autolinking-runtime-compatibility-bytecode-layouts -emit-module -emit-module-path=%t/layout_string_witnesses_types_resilient.swiftmodule %S/Inputs/layout_string_witnesses_types_resilient.swift
 // RUN: %target-build-swift -target %target-future-triple -g -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnessesInstantiation -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -enable-layout-string-value-witnesses-instantiation -Xfrontend -enable-library-evolution -c -parse-as-library -o %t/layout_string_witnesses_types_resilient.o %S/Inputs/layout_string_witnesses_types_resilient.swift
-// RUN: %target-build-swift -target %target-future-triple -g -parse-stdlib -module-name layout_string_witnesses_dynamic -llayout_string_witnesses_types -L%t %t/layout_string_witnesses_types_resilient.o -I %t -o %t/main %s %target-rpath(%t)
+// RUN: %target-build-swift -target %target-future-triple -g -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnessesInstantiation -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -enable-layout-string-value-witnesses-instantiation -parse-stdlib -module-name layout_string_witnesses_dynamic -llayout_string_witnesses_types -L%t %t/layout_string_witnesses_types_resilient.o -I %t -o %t/main %s %target-rpath(%t)
 // RUN: %target-codesign %t/main
 // RUN: %target-run %t/main %t/%target-library-name(layout_string_witnesses_types) | %FileCheck %s --check-prefix=CHECK -check-prefix=CHECK-%target-os
 
@@ -30,7 +30,7 @@ class TestClass {
 
 func testGeneric() {
     let ptr = allocateInternalGenericPtr(of: TestClass.self)
-    
+
     do {
         let x = TestClass()
         testGenericInit(ptr, to: x)
@@ -1239,6 +1239,108 @@ func testGenericResilientWithUnmanagedAndWeak() {
 
 testGenericResilientWithUnmanagedAndWeak()
 
+func testNonCopyableGenericStructSimpleClass() {
+    let ptr = UnsafeMutableBufferPointer<NonCopyableGenericStruct<SimpleClass>>.allocate(capacity: 1)
+
+    let x = NonCopyableGenericStruct(x: 23, y: SimpleClass(x: 23))
+    ptr.initializeElement(at: 0, to: x)
+
+    // CHECK-NEXT: Before deinit
+    print("Before deinit")
+
+
+    // CHECK-NEXT: SimpleClass deinitialized!
+    testGenericArrayDestroy(ptr)
+
+    ptr.deallocate()
+}
+
+testNonCopyableGenericStructSimpleClass()
+
+func testNonCopyableGenericEnumSimpleClass() {
+    let ptr = UnsafeMutableBufferPointer<NonCopyableGenericEnum<SimpleClass>>.allocate(capacity: 1)
+
+    let x = NonCopyableGenericEnum.x(23, SimpleClass(x: 23))
+    ptr.initializeElement(at: 0, to: x)
+
+    // CHECK-NEXT: Before deinit
+    print("Before deinit")
+
+
+    // CHECK-NEXT: SimpleClass deinitialized!
+    testGenericArrayDestroy(ptr)
+
+    ptr.deallocate()
+}
+
+testNonCopyableGenericEnumSimpleClass()
+
+public struct NonCopyableResilientWrapper: ~Copyable {
+    let x: SimpleResilient
+    let y: Int
+}
+
+func testNonCopyableResilientStruct() {
+    let ptr = allocateInternalGenericPtr(of: NonCopyableResilientWrapper.self)
+
+    do {
+        let x = TestClass()
+        testGenericInit(ptr, to: NonCopyableResilientWrapper(x: SimpleResilient(x: 23, y: x), y: 5))
+    }
+
+    do {
+        let y = TestClass()
+        // CHECK: Before deinit
+        print("Before deinit")
+
+        // CHECK-NEXT: TestClass deinitialized!
+        testGenericAssign(ptr, from: NonCopyableResilientWrapper(x: SimpleResilient(x: 23, y: y), y: 7))
+    }
+
+    // CHECK-NEXT: Before deinit
+    print("Before deinit")
+
+    // CHECK-NEXT: TestClass deinitialized!
+    testGenericDestroy(ptr, of: NonCopyableResilientWrapper.self)
+
+    ptr.deallocate()
+}
+
+testNonCopyableResilientStruct()
+
+public enum NonCopyableResilientEnum: ~Copyable {
+    case x(SimpleResilient, Int)
+    case y(Int)
+}
+
+func testNonCopyableResilientEnum() {
+    let ptr = allocateInternalGenericPtr(of: NonCopyableResilientEnum.self)
+
+    do {
+        let x = TestClass()
+        testGenericInit(ptr, to: NonCopyableResilientEnum.x(SimpleResilient(x: 23, y: x), 5))
+    }
+
+    do {
+        let y = TestClass()
+        // CHECK: Before deinit
+        print("Before deinit")
+
+        // CHECK-NEXT: TestClass deinitialized!
+        testGenericAssign(ptr, from: NonCopyableResilientEnum.x(SimpleResilient(x: 23, y: y), 7))
+    }
+
+    // CHECK-NEXT: Before deinit
+    print("Before deinit")
+
+    // CHECK-NEXT: TestClass deinitialized!
+    testGenericDestroy(ptr, of: NonCopyableResilientEnum.self)
+
+    ptr.deallocate()
+}
+
+testNonCopyableResilientEnum()
+
 #if os(macOS)
 
 import Foundation
diff --git a/test/Interpreter/metadata_cycles_threaded.swift b/test/Interpreter/metadata_cycles_threaded.swift
new file mode 100644
index 0000000000000..194fff0cd16fe
--- /dev/null
+++ b/test/Interpreter/metadata_cycles_threaded.swift
@@ -0,0 +1,46 @@
+// RUN: %target-run-simple-swift(%import-libdispatch)
+
+// REQUIRES: executable_test
+// REQUIRES: libdispatch
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+import Dispatch
+
+@_optimize(none) @inline(never) func forceTypeInstantiation(_: Any.Type) {}
+
+struct AnyFoo<T, U> {
+  var thing: U
+}
+
+struct S<T> {
+  var thing: T
+  var next: AnyFoo<S, T>?
+}
+
+// We want to ensure that the runtime handles legal metadata cycles when threads
+// race to instantiate the cycle. We have a cycle between S and AnyFoo, but it's
+// resolvable because AnyFoo doesn't depend on S's layout. This tests a fix for
+// a bug where the runtime's cycle detection could be overeager when multiple
+// threads raced, and flag a legal.
+//
+// Since this is a multithreading test, failures are probabilistic and each type
+// can only be tested once. The recursiveTry construct generates a large number
+// of distinct types so we can do many tests.
+func tryWithType<T>(_ t: T.Type) {
+  DispatchQueue.concurrentPerform(iterations: 5) { n in
+    forceTypeInstantiation(AnyFoo<S<T>, T>?.self)
+  }
+}
+
+struct One<T> {}
+struct Two<T> {}
+
+func recursiveTry<T>(_ t: T.Type, depth: Int = 0) {
+  if depth > 10 { return }
+  tryWithType(T.self)
+  recursiveTry(One<T>.self, depth: depth + 1)
+  recursiveTry(Two<T>.self, depth: depth + 1)
+}
+
+recursiveTry(Int.self)
diff --git a/test/Interpreter/moveonly_linkedlist.swift b/test/Interpreter/moveonly_linkedlist.swift
index d3be7489ef4bd..b063400ef52de 100644
--- a/test/Interpreter/moveonly_linkedlist.swift
+++ b/test/Interpreter/moveonly_linkedlist.swift
@@ -1,6 +1,5 @@
 // RUN: %target-run-simple-swift(-Xfrontend -sil-verify-all)
 // RUN: %target-run-simple-swift(-O -Xfrontend -sil-verify-all)
-// RUN: %target-run-simple-swift(-O -Xfrontend -sil-verify-all -Xfrontend -enable-ossa-modules)
 
 // REQUIRES: executable_test
 
diff --git a/test/Interpreter/moveonly_linkedlist_2_simple.swift b/test/Interpreter/moveonly_linkedlist_2_simple.swift
index 55f7d13d336d3..3dc1701c0426e 100644
--- a/test/Interpreter/moveonly_linkedlist_2_simple.swift
+++ b/test/Interpreter/moveonly_linkedlist_2_simple.swift
@@ -6,7 +6,6 @@
 // RUN: %FileCheck %s --check-prefix=CHECK-IR
 // RUN: %target-run-simple-swift(-parse-as-library -enable-builtin-module -Xfrontend -sil-verify-all) | %FileCheck %s
 // RUN: %target-run-simple-swift(-O -parse-as-library -enable-builtin-module -Xfrontend -sil-verify-all) | %FileCheck %s
-// RUN: %target-run-simple-swift(-O -parse-as-library -enable-builtin-module -Xfrontend -sil-verify-all -Xfrontend -enable-ossa-modules) | %FileCheck %s
 
 // REQUIRES: executable_test
 
diff --git a/test/Interpreter/objc_protocols.swift b/test/Interpreter/objc_protocols.swift
index 8b4f1bd31c9ac..3a987aceabd3d 100644
--- a/test/Interpreter/objc_protocols.swift
+++ b/test/Interpreter/objc_protocols.swift
@@ -1,4 +1,3 @@
-// REQUIRES: rdar107343134
 // RUN: %target-run-simple-swift
 // REQUIRES: executable_test
 // REQUIRES: objc_interop
diff --git a/test/Interpreter/protocol_composition_with_markers.swift b/test/Interpreter/protocol_composition_with_markers.swift
index c200dacbd843c..d20bc024599ae 100644
--- a/test/Interpreter/protocol_composition_with_markers.swift
+++ b/test/Interpreter/protocol_composition_with_markers.swift
@@ -58,3 +58,27 @@ do {
   generic(Int.self)
   // CHECK: D<Int>
 }
+
+protocol Q {
+  func update(_: [Self])
+}
+
+extension Q {
+  func update(_ arr: [Self]) { print(Self.self) }
+}
+
+do {
+  class Parent : Q {}
+  class Subclass: Parent {}
+
+  func test(_ v: Parent & Sendable) {
+    v.update([])
+  }
+
+  test(Subclass())
+  // CHECK: Subclass
+
+  let sendableV: any Subclass & Sendable = Subclass()
+  test(sendableV)
+  // CHECK: Subclass
+}
diff --git a/test/Interpreter/rdar149782365.swift b/test/Interpreter/rdar149782365.swift
new file mode 100644
index 0000000000000..01eea7d0a2e78
--- /dev/null
+++ b/test/Interpreter/rdar149782365.swift
@@ -0,0 +1,33 @@
+// RUN: %target-run-simple-swift | %FileCheck %s
+
+// REQUIRES: executable_test
+
+@_silgen_name("start")
+func start() {
+  print("init C")
+}
+@_silgen_name("barrier")
+func barrier() {
+	print("nothing uses C anymore")
+}
+@_silgen_name("end")
+func end() {
+  print("deinit C")
+}
+
+@_eagerMove class C {
+	init() { start() }
+	deinit { end() }
+}
+
+@_silgen_name("doit")
+public func main() {
+	C()
+  barrier()
+}
+
+main()
+
+// CHECK: init C
+// CHECK: deinit C
+// CHECK: nothing uses C anymore
diff --git a/test/Interpreter/reference_bindings.swift b/test/Interpreter/reference_bindings.swift
index 170bf220d4e26..a3e0e82b5f4d8 100644
--- a/test/Interpreter/reference_bindings.swift
+++ b/test/Interpreter/reference_bindings.swift
@@ -2,6 +2,7 @@
 
 // REQUIRES: executable_test
 // REQUIRES: swift_feature_ReferenceBindings
+// UNSUPPORTED: back_deployment_runtime
 
 import StdlibUnittest
 
diff --git a/test/Interpreter/typed_throws_abi.swift b/test/Interpreter/typed_throws_abi.swift
index 6a7fee8b30f34..ef2b9632d4015 100644
--- a/test/Interpreter/typed_throws_abi.swift
+++ b/test/Interpreter/typed_throws_abi.swift
@@ -1,11 +1,11 @@
 // RUN: %target-build-swift-dylib(%t/%target-library-name(TypedThrowsABI)) -enable-library-evolution %S/Inputs/typed_throws_abi_impl.swift -emit-module -emit-module-path %t/TypedThrowsABI.swiftmodule -module-name TypedThrowsABI
-// RUN: %target-codesign %t/%target-library-name(TypedThrowsABI)
 
 // RUN: %target-build-swift -parse-as-library -Xfrontend -disable-availability-checking %s -lTypedThrowsABI -I %t -L %t -o %t/main %target-rpath(%t)
-// RUN: %target-codesign %t/main
+// RUN: %target-codesign %t/main %t/%target-library-name(TypedThrowsABI)
 // RUN: %target-run %t/main %t/%target-library-name(TypedThrowsABI) | %FileCheck %s
 
 // REQUIRES: executable_test
+// UNSUPPORTED: back_deployment_runtime
 
 import TypedThrowsABI
 
diff --git a/test/Interpreter/value_generics.swift b/test/Interpreter/value_generics.swift
index 10616bfe65f14..49aff648b7883 100644
--- a/test/Interpreter/value_generics.swift
+++ b/test/Interpreter/value_generics.swift
@@ -5,7 +5,11 @@
 
 // REQUIRES: executable_test
 
-struct A<let N: Int, let M: Int> {}
+struct A<let N: Int, let M: Int> {
+  func foo() {
+    print("Lower: \(N), Upper: \(M)")
+  }
+}
 
 extension A where N == 2 {
   struct B {}
@@ -36,3 +40,24 @@ let x: A<-5, -5> = getA()
 
 // CHECK: main.A<-5, -5>
 print(_typeName(type(of: x), qualified: true))
+
+// CHECK: Lower: 1, Upper: 8
+A<1, 8>().foo()
+
+// CHECK: Lower: 0, Upper: 8
+A<0, 8>().foo()
+
+// CHECK: Lower: -1, Upper: 8
+A< -1, 8>().foo()
+
+// CHECK: Lower: -2, Upper: 8
+A< -2, 8>().foo()
+
+// CHECK: Lower: -3, Upper: 8
+A< -3, 8>().foo()
+
+// CHECK: Lower: -4, Upper: 8
+A< -4, 8>().foo()
+
+// CHECK: Lower: -5, Upper: 8
+A< -5, 8>().foo()
diff --git a/test/Interpreter/variadic_generic_tuples.swift b/test/Interpreter/variadic_generic_tuples.swift
index bdbdcd66fefe2..bc480d0f9f389 100644
--- a/test/Interpreter/variadic_generic_tuples.swift
+++ b/test/Interpreter/variadic_generic_tuples.swift
@@ -85,5 +85,19 @@ tuples.test("labels") {
   expectEqual("(label: Swift.Int, Swift.String)", _typeName(oneElementLabeledTuple(t: String.self)))
 }
 
+// https://github.com/swiftlang/swift/issues/78191
+tuples.test("fulfillment") {
+  struct S<T> {
+    let t: T
+
+    func f<each A, each B>(_ b: S<(repeat each B)>) -> S<(repeat each A, repeat each B)>
+        where T == (repeat each A) {
+      return S<(repeat each A, repeat each B)>(t: (repeat each t, repeat each b.t))
+    }
+  }
+
+  let s = S(t: "hello")
+  expectEqual("S<(String, Int, Int)>(t: (\"hello\", 1, 2))", String(describing: s.f(S(t: (1, 2)))))
+}
 
 runAllTests()
diff --git a/test/Interpreter/weak.swift b/test/Interpreter/weak.swift
index e196684e45012..7390809fde835 100644
--- a/test/Interpreter/weak.swift
+++ b/test/Interpreter/weak.swift
@@ -1,5 +1,8 @@
 // RUN: %target-run-simple-swift | %FileCheck %s
+// RUN: %target-run-simple-swift(-Xfrontend -enable-experimental-feature -Xfrontend ImmutableWeakCaptures) | %FileCheck %s --check-prefixes=CHECK
+
 // REQUIRES: executable_test
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 protocol Protocol : class {
   func noop()
@@ -76,6 +79,18 @@ func testWeakInLet() {
 
 testWeakInLet()
 
+func testWeakLet() {
+  print("testWeakLet") // CHECK-LABEL: testWeakLet
+
+  var obj: SwiftClassBase? = SwiftClass() // CHECK: SwiftClass Created
+  weak let weakRef = obj
+  printState(weakRef) // CHECK-NEXT: is present
+  obj = nil // CHECK-NEXT: SwiftClass Destroyed
+  printState(weakRef) // CHECK-NEXT: is nil
+}
+
+testWeakLet()
+
 
 //======================== Test Classbound Protocols ========================
 
diff --git a/test/Interpreter/weak_objc.swift b/test/Interpreter/weak_objc.swift
index 3bb3447b766f1..72ccead84d643 100644
--- a/test/Interpreter/weak_objc.swift
+++ b/test/Interpreter/weak_objc.swift
@@ -1,8 +1,14 @@
 // RUN: %target-build-swift %s -Xfrontend -disable-objc-attr-requires-foundation-module -o %t-main
 // RUN: %target-codesign %t-main
 // RUN: %target-run %t-main | %FileCheck %s
+
+// RUN: %target-build-swift %s -Xfrontend -disable-objc-attr-requires-foundation-module -enable-upcoming-feature ImmutableWeakCaptures -o %t-main-weak-let
+// RUN: %target-codesign %t-main-weak-let
+// RUN: %target-run %t-main-weak-let | %FileCheck %s --check-prefixes=CHECK,CHECK-WEAK-LET
+
 // REQUIRES: executable_test
 // REQUIRES: objc_interop
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 import Foundation
 
@@ -47,3 +53,29 @@ func testObjCClass() {
 }
 
 testObjCClass()
+
+func testObjCWeakLet() {
+  print("testObjCWeakLet")                // CHECK-WEAK-LET: testObjCWeakLet
+
+  var c : ObjCClassBase = ObjCClass()     // CHECK-WEAK-LET: ObjCClass Created
+  weak let w : ObjCClassBase? = c
+  printState(w)                           // CHECK-WEAK-LET-NEXT: is present
+  c = ObjCClassBase()                     // CHECK-WEAK-LET-NEXT: ObjCClass Destroyed
+  printState(w)                           // CHECK-WEAK-LET-NEXT: is nil
+}
+
+testObjCWeakLet()
+
+func testObjCWeakLetCapture() {
+  print("testObjCWeakLetCapture")         // CHECK-WEAK-LET: testObjCWeakLetCapture
+
+  var c : ObjCClassBase = ObjCClass()     // CHECK-WEAK-LET: ObjCClass Created
+  let closure: () -> ObjCClassBase? = { [weak c] in c }
+  printState(closure())                   // CHECK-WEAK-LET-NEXT: is present
+  printState(closure())                   // CHECK-WEAK-LET-NEXT: is present
+  c = ObjCClassBase()                     // CHECK-WEAK-LET-NEXT: ObjCClass Destroyed
+  printState(closure())                   // CHECK-WEAK-LET-NEXT: is nil
+  printState(closure())                   // CHECK-WEAK-LET-NEXT: is nil
+}
+
+testObjCWeakLetCapture()
diff --git a/test/Interpreter/withoutActuallyEscaping.swift b/test/Interpreter/withoutActuallyEscaping.swift
index c9a1a6dc77029..1b13db2cf7826 100644
--- a/test/Interpreter/withoutActuallyEscaping.swift
+++ b/test/Interpreter/withoutActuallyEscaping.swift
@@ -59,7 +59,7 @@ struct Context {
 
 WithoutEscapingSuite.test("ExpectCrash") {
   expectCrashLater()
-  let context = Context()
+  let context = _opaqueIdentity(Context())
   sink = letEscape(f: { print("Context: \(context.a) \(context.b)") })
 }
 
diff --git a/test/LLVMPasses/allocation-deletion.ll b/test/LLVMPasses/allocation-deletion.ll
index 81d9b181dc576..3dc2ebb2ad3f7 100644
--- a/test/LLVMPasses/allocation-deletion.ll
+++ b/test/LLVMPasses/allocation-deletion.ll
@@ -7,7 +7,7 @@ target triple = "x86_64-apple-macosx10.9"
 %swift.heapmetadata = type { ptr, ptr }
 
 declare ptr @swift_allocObject(ptr , i64, i64) nounwind
-declare void @swift_release(ptr nocapture)
+declare void @swift_release(ptr captures(none))
 declare void @swift_retain(ptr ) nounwind
 declare { i64, i64, i64 } @swift_retainAndReturnThree(ptr , i64, i64 , i64 )
 
@@ -36,7 +36,7 @@ entry:
 ; trivial_alloc_eliminate1 - Show that we can eliminate an allocation with a
 ; trivial destructor.
 @trivial_dtor_metadata = internal constant %swift.heapmetadata { ptr @trivial_dtor, ptr null }
-define internal i64 @trivial_dtor(ptr nocapture) nounwind readonly {
+define internal i64 @trivial_dtor(ptr captures(none)) nounwind readonly {
 entry:
   %1 = getelementptr inbounds %swift.refcounted, ptr %0, i64 1
   %length = load i64, ptr %1, align 8
@@ -59,7 +59,7 @@ entry:
 ; trivial_alloc_eliminate2 - Show that we can eliminate an allocation with a
 ; destructor that does a retain on the 'self' object.
 @trivial_dtor_metadata2 = internal constant %swift.heapmetadata { ptr @trivial_dtor2, ptr null }
-define internal i64 @trivial_dtor2(ptr nocapture %this) nounwind readonly {
+define internal i64 @trivial_dtor2(ptr captures(none) %this) nounwind readonly {
 entry:
   %0 = getelementptr inbounds %swift.refcounted, ptr %this, i64 1, i32 0
   store ptr inttoptr (i64 4 to ptr), ptr %0, align 8
diff --git a/test/LLVMPasses/basic.ll b/test/LLVMPasses/basic.ll
index be8b54b3e16dc..f53e1f9fc66a1 100644
--- a/test/LLVMPasses/basic.ll
+++ b/test/LLVMPasses/basic.ll
@@ -16,7 +16,7 @@ declare void @swift_unknownObjectRelease(ptr)
 declare ptr @llvm.objc.retain(ptr)
 declare void @llvm.objc.release(ptr)
 declare ptr @swift_allocObject(ptr , i64, i64) nounwind
-declare void @swift_release(ptr nocapture)
+declare void @swift_release(ptr captures(none))
 declare ptr @swift_retain(ptr returned) nounwind
 declare ptr @swift_bridgeObjectRetain(ptr)
 declare void @swift_bridgeObjectRelease(ptr)
diff --git a/test/LLVMPasses/contract.ll b/test/LLVMPasses/contract.ll
index d5081e5c9e3f9..23c05a02096b3 100644
--- a/test/LLVMPasses/contract.ll
+++ b/test/LLVMPasses/contract.ll
@@ -10,9 +10,9 @@ target triple = "x86_64-apple-macosx10.9"
 declare ptr @swift_allocObject(ptr , i64, i64) nounwind
 declare ptr @swift_bridgeObjectRetain(ptr)
 declare void @swift_bridgeObjectRelease(ptr )
-declare void @swift_release(ptr nocapture)
+declare void @swift_release(ptr captures(none))
 declare ptr @swift_retain(ptr ) nounwind
-declare void @swift_unknownObjectRelease(ptr nocapture)
+declare void @swift_unknownObjectRelease(ptr captures(none))
 declare ptr @swift_unknownObjectRetain(ptr ) nounwind
 declare void @__swift_fixLifetime(ptr)
 declare void @noread_user(ptr) readnone
diff --git a/test/LLVMPasses/crash.ll b/test/LLVMPasses/crash.ll
index 020ce65262495..1aa748c1a9254 100644
--- a/test/LLVMPasses/crash.ll
+++ b/test/LLVMPasses/crash.ll
@@ -8,7 +8,7 @@ target triple = "x86_64-apple-macosx10.9"
 
 declare { ptr, i64, ptr } @_Tsop1pFT3lhsNs6String3rhsS__S_(ptr, i64, ptr, ptr, i64, ptr)
 declare { ptr, i64, ptr } @_TNs6String24convertFromStringLiteralFT3valp_S_(ptr)
-declare void @swift_release(ptr nocapture)
+declare void @swift_release(ptr captures(none))
 
 
 @0 = private unnamed_addr constant [3 x i8] c"So\00"
diff --git a/test/LLVMPasses/disable_llvm_optzns.ll b/test/LLVMPasses/disable_llvm_optzns.ll
index e71f22ae88a5f..c0a4ba020c4bd 100644
--- a/test/LLVMPasses/disable_llvm_optzns.ll
+++ b/test/LLVMPasses/disable_llvm_optzns.ll
@@ -16,7 +16,7 @@ declare void @swift_unknownObjectRelease(ptr)
 declare ptr @llvm.objc.retain(ptr)
 declare void @llvm.objc.release(ptr)
 declare ptr @swift_allocObject(ptr , i64, i64) nounwind
-declare void @swift_release(ptr nocapture)
+declare void @swift_release(ptr captures(none))
 declare ptr @swift_retain(ptr returned) nounwind
 declare ptr @swift_bridgeObjectRetain(ptr)
 declare void @swift_bridgeObjectRelease(ptr)
diff --git a/test/LLVMPasses/missing_runtime_declarations.ll b/test/LLVMPasses/missing_runtime_declarations.ll
index 3b5c20414afc0..f20263bc8472f 100644
--- a/test/LLVMPasses/missing_runtime_declarations.ll
+++ b/test/LLVMPasses/missing_runtime_declarations.ll
@@ -3,11 +3,11 @@
 target datalayout = "e-p:64:64:64-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f16:16:16-f32:32:32-f64:64:64-f128:128:128-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-apple-macosx10.9"
 
-; CHECK: declare void @swift_bridgeObjectRelease(ptr nocapture)
+; CHECK: declare void @swift_bridgeObjectRelease(ptr captures(none))
 
 %a = type opaque
-declare void @swift_bridgeObjectRelease(ptr nocapture)
-declare ptr @swift_bridgeObjectRetain(ptr nocapture)
+declare void @swift_bridgeObjectRelease(ptr captures(none))
+declare ptr @swift_bridgeObjectRetain(ptr captures(none))
 
 ; CHECK-LABEL: define void @testcase1(ptr %0) {
 ; CHECK: entry:
diff --git a/test/LLVMPasses/release_motion_landingpad.ll b/test/LLVMPasses/release_motion_landingpad.ll
index 3a3c5ae4045f9..f6bee19d82dc5 100644
--- a/test/LLVMPasses/release_motion_landingpad.ll
+++ b/test/LLVMPasses/release_motion_landingpad.ll
@@ -3,7 +3,7 @@
 target datalayout = "e-p:64:64:64-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f16:16:16-f32:32:32-f64:64:64-f128:128:128-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-apple-macosx10.9"
 
-declare void @swift_release(ptr nocapture)
+declare void @swift_release(ptr captures(none))
 declare void @swift_retain(ptr) nounwind
 declare ptr @_Znwm(i64)
 declare i32 @__gxx_personality_v0(...)
diff --git a/test/LinkerSections/function_sections.swift b/test/LinkerSections/function_sections.swift
index f7e9df726c05a..f70e3743b97aa 100644
--- a/test/LinkerSections/function_sections.swift
+++ b/test/LinkerSections/function_sections.swift
@@ -11,4 +11,3 @@
 // GOLD: .text.$s16FunctionSections5func1yyF
 
 // LLD: .text.$s16FunctionSections5func1yyF
-// LLD-NOT: .text.$s16FunctionSections5func2yyF
diff --git a/test/Macros/Inputs/macro_library.swift b/test/Macros/Inputs/macro_library.swift
index ac1b4212ae97e..0a8e835f2d28a 100644
--- a/test/Macros/Inputs/macro_library.swift
+++ b/test/Macros/Inputs/macro_library.swift
@@ -66,3 +66,6 @@ case something
 
 @attached(peer, names: overloaded)
 public macro AcceptedDotted(_: Something) = #externalMacro(module: "MacroDefinition", type: "EmptyPeerMacro")
+
+@attached(peer, names: overloaded)
+public macro ExpandTypeError() = #externalMacro(module: "MacroDefinition", type: "ExpandTypeErrorMacro")
diff --git a/test/Macros/Inputs/syntax_macro_definitions.swift b/test/Macros/Inputs/syntax_macro_definitions.swift
index e238e3cf495fe..bdc0716a8e4f9 100644
--- a/test/Macros/Inputs/syntax_macro_definitions.swift
+++ b/test/Macros/Inputs/syntax_macro_definitions.swift
@@ -240,6 +240,15 @@ public class TupleMacro: ExpressionMacro {
   }
 }
 
+public class VoidExpressionMacro: ExpressionMacro {
+  public static func expansion(
+    of macro: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) -> ExprSyntax {
+    return "()"
+  }
+}
+
 enum CustomError: Error, CustomStringConvertible {
   case message(String)
 
@@ -1215,6 +1224,29 @@ public struct AddCompletionHandler: PeerMacro {
   }
 }
 
+public struct ExpandTypeErrorMacro: PeerMacro {
+  public static func expansion<
+    Context: MacroExpansionContext,
+    Declaration: DeclSyntaxProtocol
+  >(
+    of node: AttributeSyntax,
+    providingPeersOf declaration: Declaration,
+    in context: Context
+  ) throws -> [DeclSyntax] {
+    guard let funcDecl = declaration.as(FunctionDeclSyntax.self) else {
+      throw CustomError.message("@ExpandTypeError only works on functions")
+    }
+    return [
+      """
+      public func \(funcDecl.name)(_ bar: Int) {
+        callToMissingFunction(foo)
+      }
+      """
+    ]
+  }
+}
+
+
 public struct InvalidMacro: PeerMacro, DeclarationMacro {
   public static func expansion(
     of node: AttributeSyntax,
@@ -2019,7 +2051,7 @@ public struct DefineAnonymousTypesMacro: DeclarationMacro {
 
       results += ["""
 
-      struct \(context.makeUniqueName("name"))<T> where T == Equatable { // expect error: need 'any'
+      struct \(context.makeUniqueName("name"))<T> where T == Equatable { // expected-warning{{must be written 'any Hashable'}}
         #introduceTypeCheckingErrors // make sure we get nested errors
       }
       """]
@@ -2038,7 +2070,7 @@ public struct IntroduceTypeCheckingErrorsMacro: DeclarationMacro {
       """
 
       struct \(context.makeUniqueName("name")) {
-        struct \(context.makeUniqueName("name"))<T> where T == Hashable { // expect error: need 'any'
+        struct \(context.makeUniqueName("name"))<T> where T == Hashable { // expected-warning{{must be written 'any Hashable'}}
         }
       }
       """
@@ -2134,6 +2166,20 @@ public struct VarValueMacro: DeclarationMacro, PeerMacro {
   }
 }
 
+struct StoredPropertyMacro: DeclarationMacro {
+  public static func expansion(
+    of node: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) throws -> [DeclSyntax] {
+    guard let argument = node.arguments.first?.expression else {
+      fatalError("boom")
+    }
+    return [
+      "var storedProperty = \(argument)"
+    ]
+  }
+}
+
 public struct GenericToVoidMacro: ExpressionMacro {
   public static func expansion(
     of node: some FreestandingMacroExpansionSyntax,
@@ -2669,6 +2715,16 @@ public struct BodyMacroWithControlFlow: BodyMacro {
   }
 }
 
+struct ThrowCancellationMacro: BodyMacro {
+  static func expansion(
+    of node: AttributeSyntax,
+    providingBodyFor declaration: some DeclSyntaxProtocol & WithOptionalCodeBlockSyntax,
+    in context: some MacroExpansionContext
+  ) throws -> [CodeBlockItemSyntax] {
+    ["throw CancellationError()"]
+  }
+}
+
 @_spi(ExperimentalLanguageFeature)
 public struct TracedPreambleMacro: PreambleMacro {
   public static func expansion(
@@ -2857,6 +2913,58 @@ public struct HangingMacro: PeerMacro {
   }
 }
 
+public struct PWithNonisolatedFuncMacro: ExtensionMacro {
+  public static var inferNonisolatedConformances: Bool { false }
+
+  public static func expansion(
+    of node: AttributeSyntax,
+    attachedTo decl: some DeclGroupSyntax,
+    providingExtensionsOf type: some TypeSyntaxProtocol,
+    conformingTo protocols: [TypeSyntax],
+    in context: some MacroExpansionContext
+  ) throws -> [ExtensionDeclSyntax] {
+    if (protocols.isEmpty) {
+      return []
+    }
+
+    let decl: DeclSyntax =
+      """
+      extension \(raw: type.trimmedDescription): P {
+        nonisolated static func requirement() { }
+      }
+      """
+
+    return [
+      decl.cast(ExtensionDeclSyntax.self)
+    ]
+  }
+}
+
+public struct NonisolatedPWithNonisolatedFuncMacro: ExtensionMacro {
+  public static func expansion(
+    of node: AttributeSyntax,
+    attachedTo decl: some DeclGroupSyntax,
+    providingExtensionsOf type: some TypeSyntaxProtocol,
+    conformingTo protocols: [TypeSyntax],
+    in context: some MacroExpansionContext
+  ) throws -> [ExtensionDeclSyntax] {
+    if (protocols.isEmpty) {
+      return []
+    }
+
+    let decl: DeclSyntax =
+      """
+      extension \(raw: type.trimmedDescription): P {
+        nonisolated static func requirement() { }
+      }
+      """
+
+    return [
+      decl.cast(ExtensionDeclSyntax.self)
+    ]
+  }
+}
+
 public struct BigEndianAccessorMacro: AccessorMacro {
     public static func expansion(
         of node: AttributeSyntax,
@@ -2872,3 +2980,21 @@ public struct BigEndianAccessorMacro: AccessorMacro {
         ]
     }
 }
+
+public struct CustomConditionCheckMacro: ExpressionMacro {
+  public static func expansion(
+    of node: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) throws -> ExprSyntax {
+    guard let firstElement = node.arguments.first,
+          let stringLiteral = firstElement.expression
+      .as(StringLiteralExprSyntax.self),
+          stringLiteral.segments.count == 1,
+          case let .stringSegment(conditionName)? = stringLiteral.segments.first else {
+      throw CustomError.message("macro requires a string literal containing the name of a custom condition")
+    }
+
+    let isSet = try context.buildConfiguration?.isCustomConditionSet(name: conditionName.content.text) ?? false
+    return "\(literal: isSet)"
+  }
+}
diff --git a/test/Macros/Inputs/top_level_freestanding_other.swift b/test/Macros/Inputs/top_level_freestanding_other.swift
index c4a296a34fee5..7c3ac0214f21c 100644
--- a/test/Macros/Inputs/top_level_freestanding_other.swift
+++ b/test/Macros/Inputs/top_level_freestanding_other.swift
@@ -13,7 +13,14 @@ func deprecated() -> Int { 0 }
 var globalVar3 = #stringify({ deprecated() })
 // expected-note@-1 {{in expansion of macro 'stringify' here}}
 // expected-warning@-2{{'deprecated()' is deprecated}}
+// expected-expansion@-3:18{{
+//   expected-warning@2:9{{'deprecated()' is deprecated}}
+// }}
 
 var globalVar4 = #stringify({ deprecated() })
 // expected-note@-1 {{in expansion of macro 'stringify' here}}
 // expected-warning@-2{{'deprecated()' is deprecated}}
+// expected-expansion@-3:18{{
+//   expected-warning@2:9{{'deprecated()' is deprecated}}
+// }}
+
diff --git a/test/Macros/SwiftifyImport/CountedBy/Anonymous.swift b/test/Macros/SwiftifyImport/CountedBy/Anonymous.swift
new file mode 100644
index 0000000000000..b51125d09f992
--- /dev/null
+++ b/test/Macros/SwiftifyImport/CountedBy/Anonymous.swift
@@ -0,0 +1,47 @@
+// REQUIRES: swift_swift_parser
+
+// RUN: %target-swift-frontend %s -swift-version 5 -module-name main -typecheck -plugin-path %swift-plugin-dir -strict-memory-safety -warnings-as-errors -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines %s
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "len"))
+public func myFunc(_: UnsafePointer<CInt>, _ len: CInt) {
+}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "len"))
+public func myFunc2(_ p: UnsafePointer<CInt>, _ len: CInt, _: CInt) {
+}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "len"), .nonescaping(pointer: .param(1)))
+public func myFunc3(_: UnsafePointer<CInt>, _ len: CInt) {
+}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "len"), .nonescaping(pointer: .param(1)))
+public func myFunc4(_: UnsafeMutablePointer<CInt>, _ len: CInt) {
+}
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: public func myFunc(_ _myFunc_param0: UnsafeBufferPointer<CInt>) {
+// CHECK-NEXT:     let _myFunc_param1 = CInt(exactly: unsafe _myFunc_param0.count)!
+// CHECK-NEXT:     return unsafe myFunc(_myFunc_param0.baseAddress!, _myFunc_param1)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: public func myFunc2(_ _myFunc2_param0: UnsafeBufferPointer<CInt>, _ _myFunc2_param2: CInt) {
+// CHECK-NEXT:     let _myFunc2_param1 = CInt(exactly: unsafe _myFunc2_param0.count)!
+// CHECK-NEXT:     return unsafe myFunc2(_myFunc2_param0.baseAddress!, _myFunc2_param1, _myFunc2_param2)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: public func myFunc3(_ _myFunc3_param0: Span<CInt>) {
+// CHECK-NEXT:     let _myFunc3_param1 = CInt(exactly: _myFunc3_param0.count)!
+// CHECK-NEXT:     return unsafe _myFunc3_param0.withUnsafeBufferPointer { __myFunc3_param0Ptr in
+// CHECK-NEXT:       return unsafe myFunc3(__myFunc3_param0Ptr.baseAddress!, _myFunc3_param1)
+// CHECK-NEXT:     }
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(_myFunc4_param0: copy _myFunc4_param0) @_disfavoredOverload
+// CHECK-NEXT: public func myFunc4(_ _myFunc4_param0: inout MutableSpan<CInt>) {
+// CHECK-NEXT:     let _myFunc4_param1 = CInt(exactly: _myFunc4_param0.count)!
+// CHECK-NEXT:     return unsafe _myFunc4_param0.withUnsafeMutableBufferPointer { __myFunc4_param0Ptr in
+// CHECK-NEXT:       return unsafe myFunc4(__myFunc4_param0Ptr.baseAddress!, _myFunc4_param1)
+// CHECK-NEXT:     }
+// CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/ConstantCount.swift b/test/Macros/SwiftifyImport/CountedBy/ConstantCount.swift
new file mode 100644
index 0000000000000..08990a2af3e54
--- /dev/null
+++ b/test/Macros/SwiftifyImport/CountedBy/ConstantCount.swift
@@ -0,0 +1,190 @@
+// REQUIRES: swift_swift_parser
+
+// RUN: %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -plugin-path %swift-plugin-dir -strict-memory-safety -warnings-as-errors -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines %s
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"))
+func plain(_ ptr: UnsafePointer<CInt>) {}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"))
+func opt(_ ptr: UnsafePointer<CInt>?) {}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"))
+func mut(_ ptr: UnsafeMutablePointer<CInt>) {}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"))
+func mutOpt(_ ptr: UnsafeMutablePointer<CInt>?) {}
+
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"), .nonescaping(pointer: .param(1)))
+func noescape(_ ptr: UnsafePointer<CInt>) {}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"), .nonescaping(pointer: .param(1)))
+func noescapeOpt(_ ptr: UnsafePointer<CInt>?) {}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"), .nonescaping(pointer: .param(1)))
+func noescapeMut(_ ptr: UnsafeMutablePointer<CInt>) {}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"), .nonescaping(pointer: .param(1)))
+func noescapeMutOpt(_ ptr: UnsafeMutablePointer<CInt>?) {}
+
+
+@_SwiftifyImport(.countedBy(pointer: .return, count: "37"))
+func plainReturn() -> UnsafePointer<CInt> {}
+
+@_SwiftifyImport(.countedBy(pointer: .return, count: "37"))
+func optReturn() -> UnsafePointer<CInt>? {}
+
+@_SwiftifyImport(.countedBy(pointer: .return, count: "37"))
+func mutReturn() -> UnsafeMutablePointer<CInt> {}
+
+@_SwiftifyImport(.countedBy(pointer: .return, count: "37"))
+func mutOptReturn() -> UnsafeMutablePointer<CInt>? {}
+
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"))
+func noescape(_ ptr: UnsafePointer<CInt>) -> UnsafePointer<CInt> {}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"))
+func noescapeOpt(_ ptr: UnsafePointer<CInt>?) -> UnsafePointer<CInt>? {}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"))
+func noescapeMut(_ ptr: UnsafeMutablePointer<CInt>) -> UnsafeMutablePointer<CInt> {}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "37"))
+func noescapeMutOpt(_ ptr: UnsafeMutablePointer<CInt>?) -> UnsafeMutablePointer<CInt>? {}
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func plain(_ ptr: UnsafeBufferPointer<CInt>) {
+// CHECK-NEXT:     let _ptrCount = unsafe ptr.count
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in plain: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe plain(ptr.baseAddress!)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func opt(_ ptr: UnsafeBufferPointer<CInt>?) {
+// CHECK-NEXT:     let _ptrCount = unsafe ptr?.count ?? 0
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in opt: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe opt(ptr?.baseAddress)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func mut(_ ptr: UnsafeMutableBufferPointer<CInt>) {
+// CHECK-NEXT:     let _ptrCount = unsafe ptr.count
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in mut: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe mut(ptr.baseAddress!)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func mutOpt(_ ptr: UnsafeMutableBufferPointer<CInt>?) {
+// CHECK-NEXT:     let _ptrCount = unsafe ptr?.count ?? 0
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in mutOpt: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe mutOpt(ptr?.baseAddress)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func noescape(_ ptr: Span<CInt>) {
+// CHECK-NEXT:     let _ptrCount = ptr.count
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in noescape: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe ptr.withUnsafeBufferPointer { _ptrPtr in
+// CHECK-NEXT:       return unsafe noescape(_ptrPtr.baseAddress!)
+// CHECK-NEXT:     }
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func noescape(_ ptr: UnsafeBufferPointer<CInt>) -> UnsafePointer<CInt> {
+// CHECK-NEXT:     let _ptrCount = unsafe ptr.count
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in noescape: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe noescape(ptr.baseAddress!)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func noescapeOpt(_ ptr: Span<CInt>?) {
+// CHECK-NEXT:     let _ptrCount = ptr?.count ?? 0
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in noescapeOpt: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return { () in
+// CHECK-NEXT:         return if ptr == nil {
+// CHECK-NEXT:             unsafe noescapeOpt(nil)
+// CHECK-NEXT:           } else {
+// CHECK-NEXT:             unsafe ptr!.withUnsafeBufferPointer { _ptrPtr in
+// CHECK-NEXT:               return unsafe noescapeOpt(_ptrPtr.baseAddress)
+// CHECK-NEXT:             }
+// CHECK-NEXT:           }
+// CHECK-NEXT:     }()
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(ptr: copy ptr) @_disfavoredOverload
+// CHECK-NEXT: func noescapeMut(_ ptr: inout MutableSpan<CInt>) {
+// CHECK-NEXT:     let _ptrCount = ptr.count
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in noescapeMut: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe ptr.withUnsafeMutableBufferPointer { _ptrPtr in
+// CHECK-NEXT:       return unsafe noescapeMut(_ptrPtr.baseAddress!)
+// CHECK-NEXT:     }
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func noescapeMut(_ ptr: UnsafeMutableBufferPointer<CInt>) -> UnsafeMutablePointer<CInt> {
+// CHECK-NEXT:     let _ptrCount = unsafe ptr.count
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in noescapeMut: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe noescapeMut(ptr.baseAddress!)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload 
+// CHECK-NEXT: func noescapeMutOpt(_ ptr: UnsafeMutableBufferPointer<CInt>?) -> UnsafeMutablePointer<CInt>? {
+// CHECK-NEXT:     let _ptrCount = unsafe ptr?.count ?? 0
+// CHECK-NEXT:     if _ptrCount != 37 {
+// CHECK-NEXT:       fatalError("bounds check failure in noescapeMutOpt: expected \(37) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe noescapeMutOpt(ptr?.baseAddress)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func plainReturn() -> UnsafeBufferPointer<CInt> {
+// CHECK-NEXT:     return unsafe UnsafeBufferPointer<CInt> (start: unsafe plainReturn(), count: Int(37))
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func optReturn() -> UnsafeBufferPointer<CInt>? {
+// CHECK-NEXT:     return unsafe { () in
+// CHECK-NEXT:       let _resultValue = unsafe optReturn()
+// CHECK-NEXT:       if unsafe _resultValue == nil {
+// CHECK-NEXT:         return nil
+// CHECK-NEXT:       } else {
+// CHECK-NEXT:         return unsafe _swiftifyOverrideLifetime(UnsafeBufferPointer<CInt>(start: _resultValue!, count: Int(37)), copying: ())
+// CHECK-NEXT:       }
+// CHECK-NEXT:     }()
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func mutReturn() -> UnsafeMutableBufferPointer<CInt> {
+// CHECK-NEXT:     return unsafe UnsafeMutableBufferPointer<CInt> (start: unsafe mutReturn(), count: Int(37))
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func mutOptReturn() -> UnsafeMutableBufferPointer<CInt>? {
+// CHECK-NEXT:     return unsafe { () in
+// CHECK-NEXT:       let _resultValue = unsafe mutOptReturn()
+// CHECK-NEXT:       if unsafe _resultValue == nil {
+// CHECK-NEXT:         return nil
+// CHECK-NEXT:       } else {
+// CHECK-NEXT:         return unsafe _swiftifyOverrideLifetime(UnsafeMutableBufferPointer<CInt>(start: _resultValue!, count: Int(37)), copying: ())
+// CHECK-NEXT:       }
+// CHECK-NEXT:     }()
+// CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/CountExpr.swift b/test/Macros/SwiftifyImport/CountedBy/CountExpr.swift
index 92fe4889bdad1..8bc4018956683 100644
--- a/test/Macros/SwiftifyImport/CountedBy/CountExpr.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/CountExpr.swift
@@ -6,12 +6,11 @@
 func myFunc(_ ptr: UnsafePointer<CInt>, _ size: CInt, _ count: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeBufferPointer<CInt>, _ size: CInt, _ count: CInt) {
-// CHECK-NEXT:     let _ptrCount: some BinaryInteger = size * count
-// CHECK-NEXT:     if ptr.count < _ptrCount || _ptrCount < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
+// CHECK-NEXT:     let _ptrCount = unsafe ptr.count
+// CHECK-NEXT:     if _ptrCount != size * count {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc: expected \(size * count) but got \(_ptrCount)")
 // CHECK-NEXT:     }
 // CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, size, count)
 // CHECK-NEXT: }
-
diff --git a/test/Macros/SwiftifyImport/CountedBy/MultipleParams.swift b/test/Macros/SwiftifyImport/CountedBy/MultipleParams.swift
index 6ad7bf0cc7824..8f0ac6f8d09f1 100644
--- a/test/Macros/SwiftifyImport/CountedBy/MultipleParams.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/MultipleParams.swift
@@ -6,7 +6,9 @@
 func myFunc(_ ptr: UnsafePointer<CInt>, _ len: CInt, _ ptr2: UnsafePointer<CInt>, _ len2: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeBufferPointer<CInt>, _ ptr2: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!, ptr2.baseAddress!, CInt(exactly: ptr2.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     let len2 = CInt(exactly: unsafe ptr2.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, len, ptr2.baseAddress!, len2)
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/Mutable.swift b/test/Macros/SwiftifyImport/CountedBy/Mutable.swift
index 1df1df1329115..bb1b1f615026a 100644
--- a/test/Macros/SwiftifyImport/CountedBy/Mutable.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/Mutable.swift
@@ -6,8 +6,8 @@
 func myFunc(_ ptr: UnsafeMutablePointer<CInt>, _ len: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeMutableBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, len)
 // CHECK-NEXT: }
-
diff --git a/test/Macros/SwiftifyImport/CountedBy/MutableSpan.swift b/test/Macros/SwiftifyImport/CountedBy/MutableSpan.swift
index e03ccbcb7653b..d0458f21b1642 100644
--- a/test/Macros/SwiftifyImport/CountedBy/MutableSpan.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/MutableSpan.swift
@@ -7,9 +7,10 @@
 func myFunc(_ ptr: UnsafeMutablePointer<CInt>, _ len: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(ptr: copy ptr)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(ptr: copy ptr) @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: inout MutableSpan<CInt>) {
-// CHECK-NEXT:     return unsafe   ptr.withUnsafeMutableBufferPointer { _ptrPtr in
-// CHECK-NEXT:         return unsafe myFunc(_ptrPtr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: ptr.count)!
+// CHECK-NEXT:     return unsafe ptr.withUnsafeMutableBufferPointer { _ptrPtr in
+// CHECK-NEXT:       return unsafe myFunc(_ptrPtr.baseAddress!, len)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/NamedParams.swift b/test/Macros/SwiftifyImport/CountedBy/NamedParams.swift
index 6e450b8afa124..d75240dafec34 100644
--- a/test/Macros/SwiftifyImport/CountedBy/NamedParams.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/NamedParams.swift
@@ -26,33 +26,38 @@ func allNamed(ptr: UnsafePointer<CInt>, len: CInt) {
 func allNamedOther(buf ptr: UnsafePointer<CInt>, count len: CInt) {
 }
 
-// CHECK: @_alwaysEmitIntoClient
+// CHECK: @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func ptrNamed(ptr: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe ptrNamed(ptr: ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe ptrNamed(ptr: ptr.baseAddress!, len)
 // CHECK-NEXT: }
 
-// CHECK: @_alwaysEmitIntoClient
+// CHECK: @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func ptrNamedOther(buf ptr: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe ptrNamedOther(buf: ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe ptrNamedOther(buf: ptr.baseAddress!, len)
 // CHECK-NEXT: }
 
-// CHECK: @_alwaysEmitIntoClient
+// CHECK: @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func lenNamed(_ ptr: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe lenNamed(ptr.baseAddress!, len: CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe lenNamed(ptr.baseAddress!, len: len)
 // CHECK-NEXT: }
 
-// CHECK: @_alwaysEmitIntoClient
+// CHECK: @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func lenNamedOther(_ ptr: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe lenNamedOther(ptr.baseAddress!, count: CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe lenNamedOther(ptr.baseAddress!, count: len)
 // CHECK-NEXT: }
 
-// CHECK: @_alwaysEmitIntoClient
+// CHECK: @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func allNamed(ptr: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe allNamed(ptr: ptr.baseAddress!, len: CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe allNamed(ptr: ptr.baseAddress!, len: len)
 // CHECK-NEXT: }
 
-// CHECK: @_alwaysEmitIntoClient
+// CHECK: @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func allNamedOther(buf ptr: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe allNamedOther(buf: ptr.baseAddress!, count: CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe allNamedOther(buf: ptr.baseAddress!, count: len)
 // CHECK-NEXT: }
-
diff --git a/test/Macros/SwiftifyImport/CountedBy/Nullable.swift b/test/Macros/SwiftifyImport/CountedBy/Nullable.swift
index b0f3f2c926abe..b539c65a91aa4 100644
--- a/test/Macros/SwiftifyImport/CountedBy/Nullable.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/Nullable.swift
@@ -18,34 +18,38 @@ func myFunc3(_ ptr: UnsafeMutablePointer<CInt>?, _ len: CInt, _ ptr2: UnsafeMuta
 func myFunc4(_ ptr: UnsafeMutablePointer<CInt>?, _ len: CInt) -> UnsafeMutablePointer<CInt>? {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeBufferPointer<CInt>?) {
-// CHECK-NEXT:     return unsafe myFunc(ptr?.baseAddress, CInt(exactly: ptr?.count ?? 0)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr?.count ?? 0)!
+// CHECK-NEXT:     return unsafe myFunc(ptr?.baseAddress, len)
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(ptr: copy ptr)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(ptr: copy ptr) @_disfavoredOverload
 // CHECK-NEXT: func myFunc2(_ ptr: inout MutableSpan<CInt>?) {
+// CHECK-NEXT:     let len = CInt(exactly: ptr?.count ?? 0)!
 // CHECK-NEXT:     return { () in
 // CHECK-NEXT:         return if ptr == nil {
-// CHECK-NEXT:             unsafe myFunc2(nil, CInt(exactly: ptr?.count ?? 0)!)
+// CHECK-NEXT:             unsafe myFunc2(nil, len)
 // CHECK-NEXT:         } else {
 // CHECK-NEXT:             unsafe ptr!.withUnsafeMutableBufferPointer { _ptrPtr in
-// CHECK-NEXT:                 return unsafe myFunc2(_ptrPtr.baseAddress, CInt(exactly: ptr?.count ?? 0)!)
+// CHECK-NEXT:                 return unsafe myFunc2(_ptrPtr.baseAddress, len)
 // CHECK-NEXT:             }
 // CHECK-NEXT:         }
 // CHECK-NEXT:     }()
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(ptr: copy ptr) @lifetime(ptr2: copy ptr2)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(ptr: copy ptr) @_lifetime(ptr2: copy ptr2) @_disfavoredOverload
 // CHECK-NEXT: func myFunc3(_ ptr: inout MutableSpan<CInt>?, _ ptr2: inout MutableSpan<CInt>?) {
+// CHECK-NEXT:     let len = CInt(exactly: ptr?.count ?? 0)!
+// CHECK-NEXT:     let len2 = CInt(exactly: ptr2?.count ?? 0)!
 // CHECK-NEXT:     return { () in
 // CHECK-NEXT:         return if ptr2 == nil {
 // CHECK-NEXT:             { () in
 // CHECK-NEXT:                 return  if ptr == nil {
-// CHECK-NEXT:                     unsafe myFunc3(nil, CInt(exactly: ptr?.count ?? 0)!, nil, CInt(exactly: ptr2?.count ?? 0)!)
+// CHECK-NEXT:                     unsafe myFunc3(nil, len, nil, len2)
 // CHECK-NEXT:                 } else {
 // CHECK-NEXT:                     unsafe ptr!.withUnsafeMutableBufferPointer { _ptrPtr in
-// CHECK-NEXT:                         return unsafe myFunc3(_ptrPtr.baseAddress, CInt(exactly: ptr?.count ?? 0)!, nil, CInt(exactly: ptr2?.count ?? 0)!)
+// CHECK-NEXT:                         return unsafe myFunc3(_ptrPtr.baseAddress, len, nil, len2)
 // CHECK-NEXT:                     }
 // CHECK-NEXT:                 }
 // CHECK-NEXT:             }()
@@ -53,10 +57,10 @@ func myFunc4(_ ptr: UnsafeMutablePointer<CInt>?, _ len: CInt) -> UnsafeMutablePo
 // CHECK-NEXT:             unsafe ptr2!.withUnsafeMutableBufferPointer { _ptr2Ptr in
 // CHECK-NEXT:                 return { () in
 // CHECK-NEXT:                     return if ptr == nil {
-// CHECK-NEXT:                         unsafe myFunc3(nil, CInt(exactly: ptr?.count ?? 0)!, _ptr2Ptr.baseAddress, CInt(exactly: ptr2?.count ?? 0)!)
+// CHECK-NEXT:                         unsafe myFunc3(nil, len, _ptr2Ptr.baseAddress, len2)
 // CHECK-NEXT:                     } else {
 // CHECK-NEXT:                         unsafe ptr!.withUnsafeMutableBufferPointer { _ptrPtr in
-// CHECK-NEXT:                             return unsafe myFunc3(_ptrPtr.baseAddress, CInt(exactly: ptr?.count ?? 0)!, _ptr2Ptr.baseAddress, CInt(exactly: ptr2?.count ?? 0)!)
+// CHECK-NEXT:                             return unsafe myFunc3(_ptrPtr.baseAddress, len, _ptr2Ptr.baseAddress, len2)
 // CHECK-NEXT:                         }
 // CHECK-NEXT:                     }
 // CHECK-NEXT:                 }()
@@ -65,13 +69,10 @@ func myFunc4(_ ptr: UnsafeMutablePointer<CInt>?, _ len: CInt) -> UnsafeMutablePo
 // CHECK-NEXT:     }()
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(copy ptr) @lifetime(ptr: copy ptr)
-// CHECK-NEXT: func myFunc4(_ ptr: inout MutableSpan<CInt>?, _ len: CInt) -> MutableSpan<CInt>? {
-// CHECK-NEXT:     let _ptrCount: some BinaryInteger = len
-// CHECK-NEXT:     if ptr?.count ?? 0 < _ptrCount || _ptrCount < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
-// CHECK-NEXT:     }
-// CHECK-NEXT:     return { () in
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy ptr) @_lifetime(ptr: copy ptr) @_disfavoredOverload
+// CHECK-NEXT: func myFunc4(_ ptr: inout MutableSpan<CInt>?) -> MutableSpan<CInt>? {
+// CHECK-NEXT:     let len = CInt(exactly: ptr?.count ?? 0)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime({ () in
 // CHECK-NEXT:         let _resultValue = { () in
 // CHECK-NEXT:             return if ptr == nil {
 // CHECK-NEXT:                 unsafe myFunc4(nil, len)
@@ -84,7 +85,7 @@ func myFunc4(_ ptr: UnsafeMutablePointer<CInt>?, _ len: CInt) -> UnsafeMutablePo
 // CHECK-NEXT:         if unsafe _resultValue == nil {
 // CHECK-NEXT:             return nil
 // CHECK-NEXT:         } else {
-// CHECK-NEXT:             return unsafe MutableSpan<CInt>(_unsafeStart: _resultValue!, count: Int(len))
+// CHECK-NEXT:             return unsafe _swiftifyOverrideLifetime(MutableSpan<CInt>(_unsafeStart: _resultValue!, count: Int(len)), copying: ())
 // CHECK-NEXT:         }
-// CHECK-NEXT:     }()
-// CHECK-NEXT: }
\ No newline at end of file
+// CHECK-NEXT:     }(), copying: ())
+// CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/PointerReturn.swift b/test/Macros/SwiftifyImport/CountedBy/PointerReturn.swift
index d1de7eeadd18c..f00000a92cd42 100644
--- a/test/Macros/SwiftifyImport/CountedBy/PointerReturn.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/PointerReturn.swift
@@ -1,7 +1,7 @@
 // REQUIRES: swift_swift_parser
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
-// RUN: %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -plugin-path %swift-plugin-dir -enable-experimental-feature LifetimeDependence -strict-memory-safety -warnings-as-errors -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines %s
+// RUN: %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -plugin-path %swift-plugin-dir -enable-experimental-feature Lifetimes -strict-memory-safety -warnings-as-errors -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines %s
 
 @_SwiftifyImport(.countedBy(pointer: .return, count: "len"))
 func myFunc(_ len: CInt) -> UnsafeMutablePointer<CInt> {
@@ -28,15 +28,16 @@ func lifetimeDependentBorrow(_ p: borrowing UnsafePointer<CInt>, _ len1: CInt, _
 // CHECK-NEXT: func nonEscaping(_ len: CInt) -> UnsafeBufferPointer<CInt> {
 // CHECK-NEXT:     return unsafe UnsafeBufferPointer<CInt> (start: unsafe nonEscaping(len), count: Int(len))
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(copy p)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy p) @_disfavoredOverload
 // CHECK-NEXT: func lifetimeDependentCopy(_ p: Span<CInt>, _ len2: CInt) -> Span<CInt> {
-// CHECK-NEXT:     return unsafe Span<CInt> (_unsafeStart:   unsafe p.withUnsafeBufferPointer { _pPtr in
-// CHECK-NEXT:         return unsafe lifetimeDependentCopy(_pPtr.baseAddress!, CInt(exactly: p.count)!, len2)
-// CHECK-NEXT:       }, count: Int(len2))
+// CHECK-NEXT:     let len1 = CInt(exactly: p.count)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span<CInt> (_unsafeStart: unsafe p.withUnsafeBufferPointer { _pPtr in
+// CHECK-NEXT:       return unsafe lifetimeDependentCopy(_pPtr.baseAddress!, len1, len2)
+// CHECK-NEXT:             }, count: Int(len2)), copying: ())
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(borrow p)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(borrow p) @_disfavoredOverload
 // CHECK-NEXT: func lifetimeDependentBorrow(_ p: borrowing UnsafeBufferPointer<CInt>, _ len2: CInt) -> Span<CInt> {
-// CHECK-NEXT:     return unsafe Span<CInt> (_unsafeStart: unsafe lifetimeDependentBorrow(p.baseAddress!, CInt(exactly: p.count)!, len2), count: Int(len2))
+// CHECK-NEXT:     let len1 = CInt(exactly: unsafe p.count)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span<CInt> (_unsafeStart: unsafe lifetimeDependentBorrow(p.baseAddress!, len1, len2), count: Int(len2)), copying: ())
 // CHECK-NEXT: }
-
diff --git a/test/Macros/SwiftifyImport/CountedBy/QualifiedTypes.swift b/test/Macros/SwiftifyImport/CountedBy/QualifiedTypes.swift
index 3a7139e92f133..a8efdd51e25ab 100644
--- a/test/Macros/SwiftifyImport/CountedBy/QualifiedTypes.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/QualifiedTypes.swift
@@ -10,14 +10,14 @@ func foo(_ ptr: Swift.UnsafePointer<Swift.Int>, _ len: Swift.Int) -> Swift.Void
 func bar(_ ptr: Swift.UnsafePointer<Swift.CInt>, _ len: Swift.Int) -> () {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func foo(_ ptr: Swift.UnsafeBufferPointer<Swift.Int>) -> Swift.Void {
-// CHECK-NEXT:     return unsafe foo(ptr.baseAddress!, ptr.count)
+// CHECK-NEXT:     let len = unsafe ptr.count
+// CHECK-NEXT:     return unsafe foo(ptr.baseAddress!, len)
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func bar(_ ptr: Swift.UnsafeBufferPointer<Swift.CInt>) -> () {
-// CHECK-NEXT:     return unsafe bar(ptr.baseAddress!, ptr.count)
+// CHECK-NEXT:     let len = unsafe ptr.count
+// CHECK-NEXT:     return unsafe bar(ptr.baseAddress!, len)
 // CHECK-NEXT: }
-
-
diff --git a/test/Macros/SwiftifyImport/CountedBy/Return.swift b/test/Macros/SwiftifyImport/CountedBy/Return.swift
index ceebe3e43ac81..dab352b4cc686 100644
--- a/test/Macros/SwiftifyImport/CountedBy/Return.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/Return.swift
@@ -6,7 +6,8 @@
 func myFunc(_ ptr: UnsafePointer<CInt>, _ len: CInt) -> CInt {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeBufferPointer<CInt>) -> CInt {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, len)
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/SharedCount.swift b/test/Macros/SwiftifyImport/CountedBy/SharedCount.swift
index 71a084acb6f71..3821d0e7c660b 100644
--- a/test/Macros/SwiftifyImport/CountedBy/SharedCount.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/SharedCount.swift
@@ -6,15 +6,70 @@
 func myFunc(_ ptr: UnsafePointer<CInt>, _ ptr2: UnsafePointer<CInt>, _ len: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
-// CHECK-NEXT: func myFunc(_ ptr: UnsafeBufferPointer<CInt>, _ ptr2: UnsafeBufferPointer<CInt>, _ len: CInt) {
-// CHECK-NEXT:     let _ptrCount: some BinaryInteger = len
-// CHECK-NEXT:     if ptr.count < _ptrCount || _ptrCount < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
-// CHECK-NEXT:     }
-// CHECK-NEXT:     let _ptr2Count: some BinaryInteger = len
-// CHECK-NEXT:     if ptr2.count < _ptr2Count || _ptr2Count < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "len"), .countedBy(pointer: .param(2), count: "len * size"))
+func myFunc2(_ ptr: UnsafePointer<CInt>, _ ptr2: UnsafePointer<CInt>, _ len: CInt, _ size: CInt) {
+}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "len"), .countedBy(pointer: .param(2), count: "size"), .countedBy(pointer: .param(3), count: "len * size"))
+func myFunc3(_ ptr: UnsafePointer<CInt>, _ ptr2: UnsafePointer<CInt>, _ ptr3: UnsafePointer<CInt>, _ len: CInt, _ size: CInt) {
+}
+
+@_SwiftifyImport(.countedBy(pointer: .param(3), count: "len"), .countedBy(pointer: .param(2), count: "size"), .countedBy(pointer: .param(1), count: "len * size"))
+func myFunc4(_ ptr: UnsafePointer<CInt>, _ ptr2: UnsafePointer<CInt>, _ ptr3: UnsafePointer<CInt>, _ len: CInt, _ size: CInt) {
+}
+
+@_SwiftifyImport(.countedBy(pointer: .param(1), count: "len * size"), .countedBy(pointer: .param(3), count: "len"), .countedBy(pointer: .param(2), count: "size"))
+func myFunc5(_ ptr: UnsafePointer<CInt>, _ ptr2: UnsafePointer<CInt>, _ ptr3: UnsafePointer<CInt>, _ len: CInt, _ size: CInt) {
+}
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func myFunc(_ ptr: UnsafeBufferPointer<CInt>, _ ptr2: UnsafeBufferPointer<CInt>) {
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     if unsafe ptr2.count != len {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc: expected \(len) but got \(unsafe ptr2.count)")
 // CHECK-NEXT:     }
 // CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, ptr2.baseAddress!, len)
 // CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func myFunc2(_ ptr: UnsafeBufferPointer<CInt>, _ ptr2: UnsafeBufferPointer<CInt>, _ size: CInt) {
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     let _ptr2Count = unsafe ptr2.count
+// CHECK-NEXT:     if _ptr2Count != len * size {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc2: expected \(len * size) but got \(_ptr2Count)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe myFunc2(ptr.baseAddress!, ptr2.baseAddress!, len, size)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func myFunc3(_ ptr: UnsafeBufferPointer<CInt>, _ ptr2: UnsafeBufferPointer<CInt>, _ ptr3: UnsafeBufferPointer<CInt>) {
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr2.count)!
+// CHECK-NEXT:     let _ptr3Count = unsafe ptr3.count
+// CHECK-NEXT:     if _ptr3Count != len * size {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc3: expected \(len * size) but got \(_ptr3Count)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe myFunc3(ptr.baseAddress!, ptr2.baseAddress!, ptr3.baseAddress!, len, size)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func myFunc4(_ ptr: UnsafeBufferPointer<CInt>, _ ptr2: UnsafeBufferPointer<CInt>, _ ptr3: UnsafeBufferPointer<CInt>) {
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr2.count)!
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr3.count)!
+// CHECK-NEXT:     let _ptrCount = unsafe ptr.count
+// CHECK-NEXT:     if _ptrCount != len * size {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc4: expected \(len * size) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe myFunc4(ptr.baseAddress!, ptr2.baseAddress!, ptr3.baseAddress!, len, size)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func myFunc5(_ ptr: UnsafeBufferPointer<CInt>, _ ptr2: UnsafeBufferPointer<CInt>, _ ptr3: UnsafeBufferPointer<CInt>) {
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr2.count)!
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr3.count)!
+// CHECK-NEXT:     let _ptrCount = unsafe ptr.count
+// CHECK-NEXT:     if _ptrCount != len * size {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc5: expected \(len * size) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe myFunc5(ptr.baseAddress!, ptr2.baseAddress!, ptr3.baseAddress!, len, size)
+// CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/SimpleCount.swift b/test/Macros/SwiftifyImport/CountedBy/SimpleCount.swift
index 3f252815fc557..c5727fb0b0e34 100644
--- a/test/Macros/SwiftifyImport/CountedBy/SimpleCount.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/SimpleCount.swift
@@ -6,7 +6,8 @@
 func myFunc(_ ptr: UnsafePointer<CInt>, _ len: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, len)
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/SimpleSpan.swift b/test/Macros/SwiftifyImport/CountedBy/SimpleSpan.swift
index 69de53f1d9cf6..c6f99fa5bad85 100644
--- a/test/Macros/SwiftifyImport/CountedBy/SimpleSpan.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/SimpleSpan.swift
@@ -7,9 +7,10 @@
 func myFunc(_ ptr: UnsafePointer<CInt>, _ len: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: Span<CInt>) {
+// CHECK-NEXT:     let len = CInt(exactly: ptr.count)!
 // CHECK-NEXT:     return unsafe ptr.withUnsafeBufferPointer { _ptrPtr in
-// CHECK-NEXT:         return unsafe myFunc(_ptrPtr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:       return unsafe myFunc(_ptrPtr.baseAddress!, len)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/SimpleSpanWithReturn.swift b/test/Macros/SwiftifyImport/CountedBy/SimpleSpanWithReturn.swift
index 28f60f4971371..ac8bc628c427b 100644
--- a/test/Macros/SwiftifyImport/CountedBy/SimpleSpanWithReturn.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/SimpleSpanWithReturn.swift
@@ -7,9 +7,10 @@
 func myFunc(_ ptr: UnsafePointer<CInt>, _ len: CInt) -> CInt {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: Span<CInt>) -> CInt {
+// CHECK-NEXT:     let len = CInt(exactly: ptr.count)!
 // CHECK-NEXT:     return unsafe ptr.withUnsafeBufferPointer { _ptrPtr in
-// CHECK-NEXT:         return unsafe myFunc(_ptrPtr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:       return unsafe myFunc(_ptrPtr.baseAddress!, len)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CountedBy/SpanAndUnsafeBuffer.swift b/test/Macros/SwiftifyImport/CountedBy/SpanAndUnsafeBuffer.swift
index b7774a244aa72..1823fa3edca56 100644
--- a/test/Macros/SwiftifyImport/CountedBy/SpanAndUnsafeBuffer.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/SpanAndUnsafeBuffer.swift
@@ -8,10 +8,11 @@
 func myFunc(_ ptr1: UnsafePointer<CInt>, _ len1: CInt, _ ptr2: UnsafePointer<CInt>, _ len2: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr1: Span<CInt>, _ ptr2: UnsafeBufferPointer<CInt>) {
+// CHECK-NEXT:     let len1 = CInt(exactly: ptr1.count)!
+// CHECK-NEXT:     let len2 = CInt(exactly: unsafe ptr2.count)!
 // CHECK-NEXT:     return unsafe ptr1.withUnsafeBufferPointer { _ptr1Ptr in
-// CHECK-NEXT:         return unsafe myFunc(_ptr1Ptr.baseAddress!, CInt(exactly: ptr1.count)!, ptr2.baseAddress!, CInt(exactly: ptr2.count)!)
+// CHECK-NEXT:       return unsafe myFunc(_ptr1Ptr.baseAddress!, len1, ptr2.baseAddress!, len2)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
-
diff --git a/test/Macros/SwiftifyImport/CountedBy/Unwrapped.swift b/test/Macros/SwiftifyImport/CountedBy/Unwrapped.swift
index 8677adf97a741..3e220c1726473 100644
--- a/test/Macros/SwiftifyImport/CountedBy/Unwrapped.swift
+++ b/test/Macros/SwiftifyImport/CountedBy/Unwrapped.swift
@@ -6,8 +6,8 @@
 func myFunc(_ ptr: UnsafePointer<CInt>!, _ len: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, len)
 // CHECK-NEXT: }
-
diff --git a/test/Macros/SwiftifyImport/CountedBy/Whitespace.swift b/test/Macros/SwiftifyImport/CountedBy/Whitespace.swift
new file mode 100644
index 0000000000000..c89d07d305a1a
--- /dev/null
+++ b/test/Macros/SwiftifyImport/CountedBy/Whitespace.swift
@@ -0,0 +1,49 @@
+@_SwiftifyImport(.countedBy(pointer: .return, count: "len"), .lifetimeDependence(dependsOn: .param(1), pointer: .return, type: .copy), .countedBy(pointer: .param(1), count: "len"), .nonescaping(pointer: .param(1)), .countedBy(pointer: .param(3), count: "len2"), .nonescaping(pointer: .param(3)))
+func myFunc(_ ptr: UnsafeMutablePointer<CInt>?, _ len: CInt, _ ptr2: UnsafeMutablePointer<CInt>?, _ len2: CInt) -> UnsafeMutablePointer<CInt>? {}
+
+// REQUIRES: swift_swift_parser
+
+// RUN: %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -plugin-path %swift-plugin-dir -strict-memory-safety -warnings-as-errors -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines --strict-whitespace %s
+
+// This test is meant to act as an alarm bell to unintended changes in whitespace
+
+// CHECK:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @_lifetime(copy ptr) @_lifetime(ptr: copy ptr) @_lifetime(ptr2: copy ptr2) @_disfavoredOverload
+// CHECK-NEXT:func myFunc(_ ptr: inout MutableSpan<CInt>?, _ ptr2: inout MutableSpan<CInt>?) -> MutableSpan<CInt>? {
+// CHECK-NEXT:    let len = CInt(exactly: ptr?.count ?? 0)!
+// CHECK-NEXT:    let len2 = CInt(exactly: ptr2?.count ?? 0)!
+// CHECK-NEXT:    return unsafe _swiftifyOverrideLifetime({ () in
+// CHECK-NEXT:      let _resultValue = { () in
+// CHECK-NEXT:              return if ptr2 == nil {
+// CHECK-NEXT:                  { () in
+// CHECK-NEXT:                      return if ptr == nil {
+// CHECK-NEXT:                              unsafe myFunc(nil, len, nil, len2)
+// CHECK-NEXT:                            } else {
+// CHECK-NEXT:                              unsafe ptr!.withUnsafeMutableBufferPointer { _ptrPtr in
+// CHECK-NEXT:                                return unsafe myFunc(_ptrPtr.baseAddress, len, nil, len2)
+// CHECK-NEXT:                              }
+// CHECK-NEXT:                            }
+// CHECK-NEXT:                  }()
+// CHECK-NEXT:                } else {
+// CHECK-NEXT:                  unsafe ptr2!.withUnsafeMutableBufferPointer { _ptr2Ptr in
+// CHECK-NEXT:                    return { () in
+// CHECK-NEXT:                        return if ptr == nil {
+// CHECK-NEXT:                                unsafe myFunc(nil, len, _ptr2Ptr.baseAddress, len2)
+// CHECK-NEXT:                              } else {
+// CHECK-NEXT:                                unsafe ptr!.withUnsafeMutableBufferPointer { _ptrPtr in
+// CHECK-NEXT:                                  return unsafe myFunc(_ptrPtr.baseAddress, len, _ptr2Ptr.baseAddress, len2)
+// CHECK-NEXT:                                }
+// CHECK-NEXT:                              }
+// CHECK-NEXT:                    }()
+// CHECK-NEXT:                  }
+// CHECK-NEXT:                }
+// CHECK-NEXT:          }()
+// CHECK-NEXT:      if unsafe _resultValue == nil {
+// CHECK-NEXT:        return nil
+// CHECK-NEXT:      } else {
+// CHECK-NEXT:        return unsafe _swiftifyOverrideLifetime(MutableSpan<CInt>(_unsafeStart: _resultValue!, count: Int(len)), copying: ())
+// CHECK-NEXT:      }
+// CHECK-NEXT:        }(), copying: ())
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
diff --git a/test/Macros/SwiftifyImport/CxxSpan/LifetimeboundSpan.swift b/test/Macros/SwiftifyImport/CxxSpan/LifetimeboundSpan.swift
index 17ed319fa0fe8..37c4761fa39f1 100644
--- a/test/Macros/SwiftifyImport/CxxSpan/LifetimeboundSpan.swift
+++ b/test/Macros/SwiftifyImport/CxxSpan/LifetimeboundSpan.swift
@@ -57,67 +57,78 @@ func myFunc8(_ ptr: UnsafeRawPointer, _ span: SpanOfInt, _ count: CInt, _ size:
 func myFunc9(_ span: MutableSpanOfInt) -> MutableSpanOfInt {
 }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(copy span)
+@_SwiftifyImport(.lifetimeDependence(dependsOn: .param(1), pointer: .return, type: .copy), typeMappings: ["MutableSpanOfInt" : "std.span<CInt>"])
+func myFunc10(_ self: MutableSpanOfInt) -> MutableSpanOfInt {
+}
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy span) @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ span: Span<CInt>) -> Span<CInt> {
-// CHECK-NEXT:     return unsafe _cxxOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc(SpanOfInt(span))), copying: ())
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc(SpanOfInt(span))), copying: ())
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(borrow vec) @_disfavoredOverload
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(borrow vec) @_disfavoredOverload
 // CHECK-NEXT: func myFunc2(_ vec: borrowing VecOfInt) -> Span<CInt> {
-// CHECK-NEXT:     return unsafe _cxxOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc2(vec)), copying: ())
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc2(vec)), copying: ())
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(copy span1, copy span2)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy span1, copy span2) @_disfavoredOverload
 // CHECK-NEXT: func myFunc3(_ span1: Span<CInt>, _ span2: Span<CInt>) -> Span<CInt> {
-// CHECK-NEXT:     return unsafe _cxxOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc3(SpanOfInt(span1), SpanOfInt(span2))), copying: ())
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc3(SpanOfInt(span1), SpanOfInt(span2))), copying: ())
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(borrow vec, copy span)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(borrow vec, copy span) @_disfavoredOverload
 // CHECK-NEXT: func myFunc4(_ vec: borrowing VecOfInt, _ span: Span<CInt>) -> Span<CInt> {
-// CHECK-NEXT:     return unsafe _cxxOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc4(vec, SpanOfInt(span))), copying: ())
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc4(vec, SpanOfInt(span))), copying: ())
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(borrow self) @_disfavoredOverload
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(borrow self) @_disfavoredOverload
 // CHECK-NEXT: func myFunc5() -> Span<CInt> {
-// CHECK-NEXT:     return unsafe _cxxOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc5()), copying: ())
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe myFunc5()), copying: ())
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(copy span)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy span) @_disfavoredOverload
 // CHECK-NEXT: func myFunc6(_ span: Span<CInt>, _ ptr: RawSpan, _ count: CInt, _ size: CInt) -> Span<CInt> {
-// CHECK-NEXT:     let _ptrCount: some BinaryInteger = count * size
-// CHECK-NEXT:     if ptr.byteCount < _ptrCount || _ptrCount < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
+// CHECK-NEXT:     let _ptrCount = ptr.byteCount
+// CHECK-NEXT:     if _ptrCount != count * size {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc6: expected \(count * size) but got \(_ptrCount)")
 // CHECK-NEXT:     }
-// CHECK-NEXT:     return unsafe _cxxOverrideLifetime(Span(_unsafeCxxSpan: unsafe ptr.withUnsafeBytes { _ptrPtr in
-// CHECK-NEXT:         return unsafe myFunc6(SpanOfInt(span), _ptrPtr.baseAddress!, count, size)
-// CHECK-NEXT:     }), copying: ())
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe ptr.withUnsafeBytes { _ptrPtr in
+// CHECK-NEXT:       return unsafe myFunc6(SpanOfInt(span), _ptrPtr.baseAddress!, count, size)
+// CHECK-NEXT:             }), copying: ())
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(copy span)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy span) @_disfavoredOverload
 // CHECK-NEXT: func myFunc7(_ span: Span<CInt>, _ ptr: RawSpan, _ count: CInt, _ size: CInt) -> Span<CInt> {
-// CHECK-NEXT:     let _ptrCount: some BinaryInteger = count * size
-// CHECK-NEXT:     if ptr.byteCount < _ptrCount || _ptrCount < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
+// CHECK-NEXT:     let _ptrCount = ptr.byteCount
+// CHECK-NEXT:     if _ptrCount != count * size {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc7: expected \(count * size) but got \(_ptrCount)")
 // CHECK-NEXT:     }
-// CHECK-NEXT:     return unsafe _cxxOverrideLifetime(Span(_unsafeCxxSpan: unsafe ptr.withUnsafeBytes { _ptrPtr in
-// CHECK-NEXT:         return unsafe myFunc7(SpanOfInt(span), _ptrPtr.baseAddress!, count, size)
-// CHECK-NEXT:     }), copying: ())
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe ptr.withUnsafeBytes { _ptrPtr in
+// CHECK-NEXT:       return unsafe myFunc7(SpanOfInt(span), _ptrPtr.baseAddress!, count, size)
+// CHECK-NEXT:             }), copying: ())
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(copy span)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy span) @_disfavoredOverload
 // CHECK-NEXT: func myFunc8(_ ptr: RawSpan, _ span: Span<CInt>, _ count: CInt, _ size: CInt) -> Span<CInt> {
-// CHECK-NEXT:     let _ptrCount: some BinaryInteger = count * size
-// CHECK-NEXT:     if ptr.byteCount < _ptrCount || _ptrCount < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
+// CHECK-NEXT:     let _ptrCount = ptr.byteCount
+// CHECK-NEXT:     if _ptrCount != count * size {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc8: expected \(count * size) but got \(_ptrCount)")
 // CHECK-NEXT:     }
-// CHECK-NEXT:     return unsafe _cxxOverrideLifetime(Span(_unsafeCxxSpan: unsafe ptr.withUnsafeBytes { _ptrPtr in
-// CHECK-NEXT:         return unsafe myFunc8(_ptrPtr.baseAddress!, SpanOfInt(span), count, size)
-// CHECK-NEXT:     }), copying: ())
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(Span(_unsafeCxxSpan: unsafe ptr.withUnsafeBytes { _ptrPtr in
+// CHECK-NEXT:       return unsafe myFunc8(_ptrPtr.baseAddress!, SpanOfInt(span), count, size)
+// CHECK-NEXT:             }), copying: ())
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(copy span) @lifetime(span: copy span)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy span) @_lifetime(span: copy span) @_disfavoredOverload
 // CHECK-NEXT: func myFunc9(_ span: inout MutableSpan<CInt>) -> MutableSpan<CInt> {
-// CHECK-NEXT:     return unsafe _cxxOverrideLifetime(MutableSpan(_unsafeCxxSpan: unsafe span.withUnsafeMutableBufferPointer { _spanPtr in
-// CHECK-NEXT:         return unsafe myFunc9(MutableSpanOfInt(_spanPtr))
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(MutableSpan(_unsafeCxxSpan: unsafe span.withUnsafeMutableBufferPointer { _spanPtr in
+// CHECK-NEXT:       return unsafe myFunc9(MutableSpanOfInt(_spanPtr))
+// CHECK-NEXT:             }), copying: ())
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy `self`) @_lifetime(`self`: copy `self`) @_disfavoredOverload
+// CHECK-NEXT: func myFunc10(_ `self`: inout MutableSpan<CInt>) -> MutableSpan<CInt> {
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(MutableSpan(_unsafeCxxSpan: unsafe `self`.withUnsafeMutableBufferPointer { _selfPtr in
+// CHECK-NEXT:         return unsafe myFunc10(MutableSpanOfInt(_selfPtr))
 // CHECK-NEXT:    }), copying: ())
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/CxxSpan/NoEscapeSpan.swift b/test/Macros/SwiftifyImport/CxxSpan/NoEscapeSpan.swift
index 84474ac42795c..bd9e9451217be 100644
--- a/test/Macros/SwiftifyImport/CxxSpan/NoEscapeSpan.swift
+++ b/test/Macros/SwiftifyImport/CxxSpan/NoEscapeSpan.swift
@@ -1,7 +1,7 @@
 // REQUIRES: swift_swift_parser
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
-// RUN: %target-swift-frontend %s -cxx-interoperability-mode=default -I %S/Inputs -Xcc -std=c++20 -swift-version 5 -module-name main -disable-availability-checking -typecheck -enable-experimental-feature LifetimeDependence -plugin-path %swift-plugin-dir -strict-memory-safety -warnings-as-errors -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines %s
+// RUN: %target-swift-frontend %s -cxx-interoperability-mode=default -I %S/Inputs -Xcc -std=c++20 -swift-version 5 -module-name main -disable-availability-checking -typecheck -enable-experimental-feature Lifetimes -plugin-path %swift-plugin-dir -strict-memory-safety -warnings-as-errors -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines %s
 
 // FIXME swift-ci linux tests do not support std::span
 // UNSUPPORTED: OS=linux-gnu
@@ -25,26 +25,26 @@ func myFunc3(_ span: MutableSpanOfInt, _ secondSpan: SpanOfInt) {
 func myFunc4(_ span: MutableSpanOfInt, _ secondSpan: MutableSpanOfInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ span: Span<CInt>, _ secondSpan: SpanOfInt) {
 // CHECK-NEXT:     return unsafe myFunc(SpanOfInt(span), secondSpan)
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(span: copy span)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(span: copy span) @_disfavoredOverload
 // CHECK-NEXT: func myFunc2(_ span: inout MutableSpan<CInt>, _ secondSpan: MutableSpanOfInt) {
 // CHECK-NEXT:     return unsafe span.withUnsafeMutableBufferPointer { _spanPtr in
 // CHECK-NEXT:         return unsafe myFunc2(MutableSpanOfInt(_spanPtr), secondSpan)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(span: copy span)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(span: copy span) @_disfavoredOverload
 // CHECK-NEXT: func myFunc3(_ span: inout MutableSpan<CInt>, _ secondSpan: Span<CInt>) {
 // CHECK-NEXT:     return unsafe span.withUnsafeMutableBufferPointer { _spanPtr in
 // CHECK-NEXT:         return unsafe myFunc3(MutableSpanOfInt(_spanPtr), SpanOfInt(secondSpan))
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(span: copy span) @lifetime(secondSpan: copy secondSpan)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(span: copy span) @_lifetime(secondSpan: copy secondSpan) @_disfavoredOverload
 // CHECK-NEXT: func myFunc4(_ span: inout MutableSpan<CInt>, _ secondSpan: inout MutableSpan<CInt>) {
 // CHECK-NEXT:     return unsafe secondSpan.withUnsafeMutableBufferPointer { _secondSpanPtr in
 // CHECK-NEXT:         return unsafe span.withUnsafeMutableBufferPointer { _spanPtr in
diff --git a/test/Macros/SwiftifyImport/MacroErrors/Pointee.swift b/test/Macros/SwiftifyImport/MacroErrors/Pointee.swift
index 1809dee3e897d..afd2e9df7910e 100644
--- a/test/Macros/SwiftifyImport/MacroErrors/Pointee.swift
+++ b/test/Macros/SwiftifyImport/MacroErrors/Pointee.swift
@@ -2,18 +2,12 @@
 
 // RUN: %target-typecheck-verify-swift -swift-version 5 -module-name main -disable-availability-checking -typecheck -plugin-path %swift-plugin-dir -verify
 
-// expected-error@+2{{SizedBy only supported for raw pointers}}
-@_SwiftifyImport(.sizedBy(pointer: .param(1), size: "size"))
-func myFunc(_ ptr: UnsafePointer<Int>, _ size: CInt) {
-}
-
-// expected-error@+2{{raw pointers only supported for SizedBy}}
+// expected-error@+2{{void pointers not supported for countedBy}}
 @_SwiftifyImport(.countedBy(pointer: .param(1), count: "count"))
 func myFunc(_ ptr: UnsafeRawPointer, _ count: CInt) {
 }
 
-// expected-error@+2{{raw pointers only supported for SizedBy}}
+// expected-error@+2{{void pointers not supported for countedBy}}
 @_SwiftifyImport(.countedBy(pointer: .param(1), count: "count"))
 func myFunc(_ ptr: OpaquePointer, _ count: CInt) {
 }
-
diff --git a/test/Macros/SwiftifyImport/MacroErrors/UnexpectedCountType.swift b/test/Macros/SwiftifyImport/MacroErrors/UnexpectedCountType.swift
index 6a230425c477c..239436936c6c9 100644
--- a/test/Macros/SwiftifyImport/MacroErrors/UnexpectedCountType.swift
+++ b/test/Macros/SwiftifyImport/MacroErrors/UnexpectedCountType.swift
@@ -1,17 +1,23 @@
-// REQUIRES: swift_swift_parser
-
-// XFAIL: *
-
-// RUN: not %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -plugin-path %swift-plugin-dir -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines %s
-// RUN: %target-typecheck-verify-swift %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -plugin-path %swift-plugin-dir -verify
-
+//--- test.swift
 @_SwiftifyImport(.countedBy(pointer: .param(1), count: "len"))
 func myFunc(_ ptr: UnsafePointer<CInt>, _ len: String) {
 }
+// expected-note@-3 2{{in expansion of macro '_SwiftifyImport' on global function 'myFunc' here}}
+
+// expected-error@@__swiftmacro_4main6myFunc15_SwiftifyImportfMp_.swift:4:15{{no exact matches in call to initializer}}
+// expected-error@@__swiftmacro_4main6myFunc15_SwiftifyImportfMp_.swift:4:48{{cannot force unwrap value of non-optional type 'String'}}
 
-// CHECK:      @_alwaysEmitIntoClient
-// CHECK-NEXT: func myFunc(_ ptr: UnsafeBufferPointer<CInt>) {
-// CHECK-NEXT:     myFunc(ptr.baseAddress!, String(exactly: ptr.count)!)
-// CHECK-NEXT: }
+// REQUIRES: swift_swift_parser
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend %t/test.swift -swift-version 5 -module-name main -disable-availability-checking -typecheck -plugin-path %swift-plugin-dir -dump-macro-expansions -verify -verify-ignore-unrelated 2>&1 | %FileCheck %s --match-full-lines --strict-whitespace
 
-// expected-error@_SwiftifyImport:2{{no exact matches in call to initializer}}
+// CHECK:@__swiftmacro_4main6myFunc15_SwiftifyImportfMp_.swift
+// CHECK-NEXT:------------------------------
+// CHECK-NEXT:/// This is an auto-generated wrapper for safer interop
+// CHECK-NEXT:@_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT:func myFunc(_ ptr: UnsafeBufferPointer<CInt>) {
+// CHECK-NEXT:    let len = String(exactly: unsafe ptr.count)!
+// CHECK-NEXT:    return unsafe myFunc(ptr.baseAddress!, len)
+// CHECK-NEXT:}
+// CHECK-NEXT:------------------------------
diff --git a/test/Macros/SwiftifyImport/SizedBy/MultipleParams.swift b/test/Macros/SwiftifyImport/SizedBy/MultipleParams.swift
index 912c9dbcd8822..dbf142efcfe87 100644
--- a/test/Macros/SwiftifyImport/SizedBy/MultipleParams.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/MultipleParams.swift
@@ -6,7 +6,9 @@
 func myFunc(_ ptr: UnsafeRawPointer, _ size: CInt, _ ptr2: UnsafeRawPointer, _ size2: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeRawBufferPointer, _ ptr2: UnsafeRawBufferPointer) {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!, ptr2.baseAddress!, CInt(exactly: ptr2.count)!)
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     let size2 = CInt(exactly: unsafe ptr2.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, size, ptr2.baseAddress!, size2)
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/Mutable.swift b/test/Macros/SwiftifyImport/SizedBy/Mutable.swift
index 1e8e9d9023d84..7cb497c206587 100644
--- a/test/Macros/SwiftifyImport/SizedBy/Mutable.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/Mutable.swift
@@ -6,7 +6,8 @@
 func myFunc(_ ptr: UnsafeMutableRawPointer, _ size: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeMutableRawBufferPointer) {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, size)
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/MutableRawSpan.swift b/test/Macros/SwiftifyImport/SizedBy/MutableRawSpan.swift
index 912329466aca3..738eee5c2627f 100644
--- a/test/Macros/SwiftifyImport/SizedBy/MutableRawSpan.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/MutableRawSpan.swift
@@ -7,9 +7,10 @@
 func myFunc(_ ptr: UnsafeMutableRawPointer, _ size: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient @lifetime(ptr: copy ptr)
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(ptr: copy ptr) @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: inout MutableRawSpan) {
+// CHECK-NEXT:     let size = CInt(exactly: ptr.byteCount)!
 // CHECK-NEXT:     return unsafe ptr.withUnsafeMutableBytes { _ptrPtr in
-// CHECK-NEXT:         return unsafe myFunc(_ptrPtr.baseAddress!, CInt(exactly: ptr.byteCount)!)
+// CHECK-NEXT:       return unsafe myFunc(_ptrPtr.baseAddress!, size)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/Nullable.swift b/test/Macros/SwiftifyImport/SizedBy/Nullable.swift
index 6a8059725c4c6..35a2204cc6132 100644
--- a/test/Macros/SwiftifyImport/SizedBy/Nullable.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/Nullable.swift
@@ -6,7 +6,86 @@
 func myFunc(_ ptr: UnsafeRawPointer?, _ size: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+@_SwiftifyImport(.sizedBy(pointer: .param(1), size: "len"), .nonescaping(pointer: .param(1)))
+func myFunc2(_ ptr: UnsafeMutableRawPointer?, _ len: CInt) {
+}
+
+@_SwiftifyImport(.sizedBy(pointer: .param(1), size: "len"), .nonescaping(pointer: .param(1)), .sizedBy(pointer: .param(3), size: "len2"), .nonescaping(pointer: .param(3)))
+func myFunc3(_ ptr: UnsafeMutableRawPointer?, _ len: CInt, _ ptr2: UnsafeMutableRawPointer?, _ len2: CInt) {
+}
+
+@_SwiftifyImport(.sizedBy(pointer: .param(1), size: "len"), .sizedBy(pointer: .return, size: "len"), .lifetimeDependence(dependsOn: .param(1), pointer: .return, type: .copy))
+func myFunc4(_ ptr: UnsafeMutableRawPointer?, _ len: CInt) -> UnsafeMutableRawPointer? {
+}
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeRawBufferPointer?) {
-// CHECK-NEXT:     return unsafe myFunc(ptr?.baseAddress, CInt(exactly: ptr?.count ?? 0)!)
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr?.count ?? 0)!
+// CHECK-NEXT:     return unsafe myFunc(ptr?.baseAddress, size)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(ptr: copy ptr) @_disfavoredOverload
+// CHECK-NEXT: func myFunc2(_ ptr: inout MutableRawSpan?) {
+// CHECK-NEXT:     let len = CInt(exactly: ptr?.byteCount ?? 0)!
+// CHECK-NEXT:     return { () in
+// CHECK-NEXT:         return if ptr == nil {
+// CHECK-NEXT:             unsafe myFunc2(nil, len)
+// CHECK-NEXT:           } else {
+// CHECK-NEXT:             unsafe ptr!.withUnsafeMutableBytes { _ptrPtr in
+// CHECK-NEXT:               return unsafe myFunc2(_ptrPtr.baseAddress, len)
+// CHECK-NEXT:             }
+// CHECK-NEXT:           }
+// CHECK-NEXT:     }()
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(ptr: copy ptr) @_lifetime(ptr2: copy ptr2) @_disfavoredOverload
+// CHECK-NEXT: func myFunc3(_ ptr: inout MutableRawSpan?, _ ptr2: inout MutableRawSpan?) {
+// CHECK-NEXT:     let len = CInt(exactly: ptr?.byteCount ?? 0)!
+// CHECK-NEXT:     let len2 = CInt(exactly: ptr2?.byteCount ?? 0)!
+// CHECK-NEXT:     return { () in
+// CHECK-NEXT:         return if ptr2 == nil {
+// CHECK-NEXT:             { () in
+// CHECK-NEXT:                 return if ptr == nil {
+// CHECK-NEXT:                         unsafe myFunc3(nil, len, nil, len2)
+// CHECK-NEXT:                       } else {
+// CHECK-NEXT:                         unsafe ptr!.withUnsafeMutableBytes { _ptrPtr in
+// CHECK-NEXT:                           return unsafe myFunc3(_ptrPtr.baseAddress, len, nil, len2)
+// CHECK-NEXT:                         }
+// CHECK-NEXT:                       }
+// CHECK-NEXT:             }()
+// CHECK-NEXT:           } else {
+// CHECK-NEXT:             unsafe ptr2!.withUnsafeMutableBytes { _ptr2Ptr in
+// CHECK-NEXT:               return { () in
+// CHECK-NEXT:                   return if ptr == nil {
+// CHECK-NEXT:                           unsafe myFunc3(nil, len, _ptr2Ptr.baseAddress, len2)
+// CHECK-NEXT:                         } else {
+// CHECK-NEXT:                           unsafe ptr!.withUnsafeMutableBytes { _ptrPtr in
+// CHECK-NEXT:                             return unsafe myFunc3(_ptrPtr.baseAddress, len, _ptr2Ptr.baseAddress, len2)
+// CHECK-NEXT:                           }
+// CHECK-NEXT:                         }
+// CHECK-NEXT:               }()
+// CHECK-NEXT:             }
+// CHECK-NEXT:           }
+// CHECK-NEXT:     }()
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy ptr) @_lifetime(ptr: copy ptr) @_disfavoredOverload
+// CHECK-NEXT: func myFunc4(_ ptr: inout MutableRawSpan?) -> MutableRawSpan? {
+// CHECK-NEXT:     let len = CInt(exactly: ptr?.byteCount ?? 0)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime({ () in
+// CHECK-NEXT:       let _resultValue = { () in
+// CHECK-NEXT:               return if ptr == nil {
+// CHECK-NEXT:                   unsafe myFunc4(nil, len)
+// CHECK-NEXT:                 } else {
+// CHECK-NEXT:                   unsafe ptr!.withUnsafeMutableBytes { _ptrPtr in
+// CHECK-NEXT:                     return unsafe myFunc4(_ptrPtr.baseAddress, len)
+// CHECK-NEXT:                   }
+// CHECK-NEXT:                 }
+// CHECK-NEXT:           }()
+// CHECK-NEXT:       if unsafe _resultValue == nil {
+// CHECK-NEXT:         return nil
+// CHECK-NEXT:       } else {
+// CHECK-NEXT:         return unsafe _swiftifyOverrideLifetime(MutableRawSpan(_unsafeStart: _resultValue!, byteCount: Int(len)), copying: ())
+// CHECK-NEXT:       }
+// CHECK-NEXT:         }(), copying: ())
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/Opaque.swift b/test/Macros/SwiftifyImport/SizedBy/Opaque.swift
index c396d7f9cc295..72bf7ba8e7a96 100644
--- a/test/Macros/SwiftifyImport/SizedBy/Opaque.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/Opaque.swift
@@ -26,45 +26,49 @@ func nullableSpan(_ ptr: OpaquePointer?, _ size: CInt) {
 func impNullableSpan(_ ptr: OpaquePointer!, _ size: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func nonnullUnsafeRawBufferPointer(_ ptr: UnsafeRawBufferPointer) {
-// CHECK-NEXT:     return unsafe nonnullUnsafeRawBufferPointer(OpaquePointer(ptr.baseAddress!), CInt(exactly: ptr.count)!)
-// CHECK-NEXT: }
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe nonnullUnsafeRawBufferPointer(OpaquePointer(ptr.baseAddress!), size)
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func nullableUnsafeRawBufferPointer(_ ptr: UnsafeRawBufferPointer?) {
-// CHECK-NEXT:     return unsafe nullableUnsafeRawBufferPointer(OpaquePointer(ptr?.baseAddress), CInt(exactly: ptr?.count ?? 0)!)
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr?.count ?? 0)!
+// CHECK-NEXT:     return unsafe nullableUnsafeRawBufferPointer(OpaquePointer(ptr?.baseAddress), size)
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func impNullableUnsafeRawBufferPointer(_ ptr: UnsafeRawBufferPointer) {
-// CHECK-NEXT:     return unsafe impNullableUnsafeRawBufferPointer(OpaquePointer(ptr.baseAddress!), CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe impNullableUnsafeRawBufferPointer(OpaquePointer(ptr.baseAddress!), size)
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func nonnullSpan(_ ptr: RawSpan) {
+// CHECK-NEXT:     let size = CInt(exactly: ptr.byteCount)!
 // CHECK-NEXT:     return unsafe ptr.withUnsafeBytes { _ptrPtr in
-// CHECK-NEXT:         return unsafe nonnullSpan(OpaquePointer(_ptrPtr.baseAddress!), CInt(exactly: ptr.byteCount)!)
+// CHECK-NEXT:       return unsafe nonnullSpan(OpaquePointer(_ptrPtr.baseAddress!), size)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func nullableSpan(_ ptr: RawSpan?) {
+// CHECK-NEXT:     let size = CInt(exactly: ptr?.byteCount ?? 0)!
 // CHECK-NEXT:     return { () in
 // CHECK-NEXT:         return if ptr == nil {
-// CHECK-NEXT:             unsafe nullableSpan(nil, CInt(exactly: ptr?.byteCount ?? 0)!)
-// CHECK-NEXT:         } else {
+// CHECK-NEXT:             unsafe nullableSpan(nil, size)
+// CHECK-NEXT:           } else {
 // CHECK-NEXT:             unsafe ptr!.withUnsafeBytes { _ptrPtr in
-// CHECK-NEXT:                 return unsafe nullableSpan(OpaquePointer(_ptrPtr.baseAddress), CInt(exactly: ptr?.byteCount ?? 0)!)
+// CHECK-NEXT:               return unsafe nullableSpan(OpaquePointer(_ptrPtr.baseAddress), size)
 // CHECK-NEXT:             }
-// CHECK-NEXT:         }
+// CHECK-NEXT:           }
 // CHECK-NEXT:     }()
 // CHECK-NEXT: }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func impNullableSpan(_ ptr: RawSpan) {
+// CHECK-NEXT:     let size = CInt(exactly: ptr.byteCount)!
 // CHECK-NEXT:     return unsafe ptr.withUnsafeBytes { _ptrPtr in
-// CHECK-NEXT:         return unsafe impNullableSpan(OpaquePointer(_ptrPtr.baseAddress!), CInt(exactly: ptr.byteCount)!)
+// CHECK-NEXT:       return unsafe impNullableSpan(OpaquePointer(_ptrPtr.baseAddress!), size)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
-
diff --git a/test/Macros/SwiftifyImport/SizedBy/PointerReturn.swift b/test/Macros/SwiftifyImport/SizedBy/PointerReturn.swift
new file mode 100644
index 0000000000000..08b9ba644cd48
--- /dev/null
+++ b/test/Macros/SwiftifyImport/SizedBy/PointerReturn.swift
@@ -0,0 +1,66 @@
+// REQUIRES: swift_swift_parser
+// REQUIRES: swift_feature_Lifetimes
+
+// RUN: %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -plugin-path %swift-plugin-dir -enable-experimental-feature Lifetimes -strict-memory-safety -warnings-as-errors -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines %s
+
+@_SwiftifyImport(.sizedBy(pointer: .return, size: "len"))
+func myFunc(_ len: CInt) -> UnsafeMutableRawPointer {
+}
+
+@_SwiftifyImport(.sizedBy(pointer: .return, size: "len"), .nonescaping(pointer: .return))
+func nonEscaping(_ len: CInt) -> UnsafeRawPointer {
+}
+
+@_SwiftifyImport(.sizedBy(pointer: .return, size: "len2"), .sizedBy(pointer: .param(1), size: "len1"), .lifetimeDependence(dependsOn: .param(1), pointer: .return, type: .copy))
+func lifetimeDependentCopy(_ p: UnsafeRawPointer, _ len1: CInt, _ len2: CInt) -> UnsafeRawPointer {
+}
+
+@_SwiftifyImport(.sizedBy(pointer: .return, size: "len2"), .sizedBy(pointer: .param(1), size: "len1"), .lifetimeDependence(dependsOn: .param(1), pointer: .return, type: .borrow))
+func lifetimeDependentBorrow(_ p: borrowing UnsafeRawPointer, _ len1: CInt, _ len2: CInt) -> UnsafeRawPointer {
+}
+
+@_SwiftifyImport(.sizedBy(pointer: .return, size: "len2"), .sizedBy(pointer: .param(1), size: "len1"), .lifetimeDependence(dependsOn: .param(1), pointer: .return, type: .copy))
+func lifetimeDependentCopyMut(_ p: UnsafeMutableRawPointer, _ len1: CInt, _ len2: CInt) -> UnsafeMutableRawPointer {
+}
+
+@_SwiftifyImport(.sizedBy(pointer: .return, size: "len2"), .sizedBy(pointer: .param(1), size: "len1"), .lifetimeDependence(dependsOn: .param(1), pointer: .return, type: .borrow))
+func lifetimeDependentBorrowMut(_ p: borrowing UnsafeMutableRawPointer, _ len1: CInt, _ len2: CInt) -> UnsafeMutableRawPointer {
+}
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func myFunc(_ len: CInt) -> UnsafeMutableRawBufferPointer {
+// CHECK-NEXT:     return unsafe UnsafeMutableRawBufferPointer(start: unsafe myFunc(len), count: Int(len))
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func nonEscaping(_ len: CInt) -> UnsafeRawBufferPointer {
+// CHECK-NEXT:     return unsafe UnsafeRawBufferPointer(start: unsafe nonEscaping(len), count: Int(len))
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy p) @_disfavoredOverload
+// CHECK-NEXT: func lifetimeDependentCopy(_ p: RawSpan, _ len2: CInt) -> RawSpan {
+// CHECK-NEXT:     let len1 = CInt(exactly: p.byteCount)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(RawSpan(_unsafeStart: unsafe p.withUnsafeBytes { _pPtr in
+// CHECK-NEXT:       return unsafe lifetimeDependentCopy(_pPtr.baseAddress!, len1, len2)
+// CHECK-NEXT:             }, byteCount: Int(len2)), copying: ())
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(borrow p) @_disfavoredOverload
+// CHECK-NEXT: func lifetimeDependentBorrow(_ p: borrowing UnsafeRawBufferPointer, _ len2: CInt) -> RawSpan {
+// CHECK-NEXT:     let len1 = CInt(exactly: unsafe p.count)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(RawSpan(_unsafeStart: unsafe lifetimeDependentBorrow(p.baseAddress!, len1, len2), byteCount: Int(len2)), copying: ())
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy p) @_lifetime(p: copy p) @_disfavoredOverload
+// CHECK-NEXT: func lifetimeDependentCopyMut(_ p: inout MutableRawSpan, _ len2: CInt) -> MutableRawSpan {
+// CHECK-NEXT:     let len1 = CInt(exactly: p.byteCount)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(MutableRawSpan(_unsafeStart: unsafe p.withUnsafeMutableBytes { _pPtr in
+// CHECK-NEXT:       return unsafe lifetimeDependentCopyMut(_pPtr.baseAddress!, len1, len2)
+// CHECK-NEXT:             }, byteCount: Int(len2)), copying: ())
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(borrow p) @_disfavoredOverload
+// CHECK-NEXT: func lifetimeDependentBorrowMut(_ p: borrowing UnsafeMutableRawBufferPointer, _ len2: CInt) -> MutableRawSpan {
+// CHECK-NEXT:     let len1 = CInt(exactly: unsafe p.count)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(MutableRawSpan(_unsafeStart: unsafe lifetimeDependentBorrowMut(p.baseAddress!, len1, len2), byteCount: Int(len2)), copying: ())
+// CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/Return.swift b/test/Macros/SwiftifyImport/SizedBy/Return.swift
index 61dcbc9764861..346a1835f77a8 100644
--- a/test/Macros/SwiftifyImport/SizedBy/Return.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/Return.swift
@@ -6,7 +6,8 @@
 func myFunc(_ ptr: UnsafeRawPointer, _ size: CInt) -> CInt {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeRawBufferPointer) -> CInt {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, size)
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/SharedCount.swift b/test/Macros/SwiftifyImport/SizedBy/SharedCount.swift
index 2d331b9c19805..524e901b8ae5f 100644
--- a/test/Macros/SwiftifyImport/SizedBy/SharedCount.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/SharedCount.swift
@@ -6,15 +6,11 @@
 func myFunc(_ ptr: UnsafeRawPointer, _ ptr2: UnsafeRawPointer, _ size: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
-// CHECK-NEXT: func myFunc(_ ptr: UnsafeRawBufferPointer, _ ptr2: UnsafeRawBufferPointer, _ size: CInt) {
-// CHECK-NEXT:     let _ptrCount: some BinaryInteger = size
-// CHECK-NEXT:     if ptr.count < _ptrCount || _ptrCount < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
-// CHECK-NEXT:     }
-// CHECK-NEXT:     let _ptr2Count: some BinaryInteger = size
-// CHECK-NEXT:     if ptr2.count < _ptr2Count || _ptr2Count < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func myFunc(_ ptr: UnsafeRawBufferPointer, _ ptr2: UnsafeRawBufferPointer) {
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     if unsafe ptr2.count != size {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc: expected \(size) but got \(unsafe ptr2.count)")
 // CHECK-NEXT:     }
 // CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, ptr2.baseAddress!, size)
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/SimpleRawSpan.swift b/test/Macros/SwiftifyImport/SizedBy/SimpleRawSpan.swift
index c7ed798638e34..bb53ff31997c5 100644
--- a/test/Macros/SwiftifyImport/SizedBy/SimpleRawSpan.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/SimpleRawSpan.swift
@@ -7,9 +7,10 @@
 func myFunc(_ ptr: UnsafeRawPointer, _ size: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: RawSpan) {
+// CHECK-NEXT:     let size = CInt(exactly: ptr.byteCount)!
 // CHECK-NEXT:     return unsafe ptr.withUnsafeBytes { _ptrPtr in
-// CHECK-NEXT:         return unsafe myFunc(_ptrPtr.baseAddress!, CInt(exactly: ptr.byteCount)!)
+// CHECK-NEXT:       return unsafe myFunc(_ptrPtr.baseAddress!, size)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/SimpleRawSpanWithReturn.swift b/test/Macros/SwiftifyImport/SizedBy/SimpleRawSpanWithReturn.swift
index 92586787da5b1..418290c939ab4 100644
--- a/test/Macros/SwiftifyImport/SizedBy/SimpleRawSpanWithReturn.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/SimpleRawSpanWithReturn.swift
@@ -7,9 +7,10 @@
 func myFunc(_ ptr: UnsafeRawPointer, _ size: CInt) -> CInt {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: RawSpan) -> CInt {
+// CHECK-NEXT:     let size = CInt(exactly: ptr.byteCount)!
 // CHECK-NEXT:     return unsafe ptr.withUnsafeBytes { _ptrPtr in
-// CHECK-NEXT:         return unsafe myFunc(_ptrPtr.baseAddress!, CInt(exactly: ptr.byteCount)!)
+// CHECK-NEXT:       return unsafe myFunc(_ptrPtr.baseAddress!, size)
 // CHECK-NEXT:     }
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/SimpleSize.swift b/test/Macros/SwiftifyImport/SizedBy/SimpleSize.swift
index 803d81e788d1f..580ec4298bc52 100644
--- a/test/Macros/SwiftifyImport/SizedBy/SimpleSize.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/SimpleSize.swift
@@ -6,7 +6,8 @@
 func myFunc(_ ptr: UnsafeRawPointer, _ size: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeRawBufferPointer) {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, size)
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/SizeExpr.swift b/test/Macros/SwiftifyImport/SizedBy/SizeExpr.swift
index 506ae8da2b687..76c9bb716007e 100644
--- a/test/Macros/SwiftifyImport/SizedBy/SizeExpr.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/SizeExpr.swift
@@ -6,11 +6,11 @@
 func myFunc(_ ptr: UnsafeRawPointer, _ size: CInt, _ count: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeRawBufferPointer, _ size: CInt, _ count: CInt) {
-// CHECK-NEXT:     let _ptrCount: some BinaryInteger = size * count
-// CHECK-NEXT:     if ptr.count < _ptrCount || _ptrCount < 0 {
-// CHECK-NEXT:         fatalError("bounds check failure when calling unsafe function")
+// CHECK-NEXT:     let _ptrCount = unsafe ptr.count
+// CHECK-NEXT:     if _ptrCount != size * count {
+// CHECK-NEXT:       fatalError("bounds check failure in myFunc: expected \(size * count) but got \(_ptrCount)")
 // CHECK-NEXT:     }
 // CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, size, count)
 // CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/TypedPointer.swift b/test/Macros/SwiftifyImport/SizedBy/TypedPointer.swift
new file mode 100644
index 0000000000000..b74948b450990
--- /dev/null
+++ b/test/Macros/SwiftifyImport/SizedBy/TypedPointer.swift
@@ -0,0 +1,108 @@
+// REQUIRES: swift_swift_parser
+// REQUIRES: swift_feature_LifetimeDependence
+
+// RUN: %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -enable-experimental-feature LifetimeDependence -plugin-path %swift-plugin-dir -strict-memory-safety -warnings-as-errors -dump-macro-expansions 2>&1 | %FileCheck --match-full-lines %s
+
+@_SwiftifyImport(.sizedBy(pointer: .param(1), size: "size"))
+func constParam(_ ptr: UnsafePointer<CChar>, _ size: CInt) {}
+
+@_SwiftifyImport(.sizedBy(pointer: .param(1), size: "size"))
+func mutParam(_ ptr: UnsafeMutablePointer<UInt8>, _ size: CInt) {}
+
+@_SwiftifyImport(.sizedBy(pointer: .param(1), size: "size * count"))
+func exprParam(_ ptr: UnsafeMutablePointer<UInt8>, _ size: CInt, _ count: CInt) {}
+
+@_SwiftifyImport(.sizedBy(pointer: .return, size: "size"))
+func constReturn(_ size: CInt) -> UnsafePointer<CChar> {}
+
+@_SwiftifyImport(.sizedBy(pointer: .return, size: "size"))
+func mutReturn(_ size: CInt) -> UnsafeMutablePointer<UInt8> {}
+
+@_SwiftifyImport(.sizedBy(pointer: .return, size: "size * count"))
+func exprReturn(_ size: CInt, _ count: CInt) -> UnsafeMutablePointer<UInt8> {}
+
+@_SwiftifyImport(.sizedBy(pointer: .param(1), size: "size"),
+                 .nonescaping(pointer: .param(1)))
+func constParamNoreturn(_ ptr: UnsafePointer<CChar>, _ size: CInt) {}
+
+@_SwiftifyImport(.sizedBy(pointer: .param(1), size: "size"),
+                 .nonescaping(pointer: .param(1)))
+func mutParamNoreturn(_ ptr: UnsafeMutablePointer<UInt8>, _ size: CInt) {}
+
+@_SwiftifyImport(.sizedBy(pointer: .param(2), size: "size"),
+                 .sizedBy(pointer: .return, size: "size"),
+                 .lifetimeDependence(dependsOn: .param(2), pointer: .return, type: .copy))
+func constReturnDependence(_ size: CInt, _ ptr: UnsafePointer<UInt8>) -> UnsafePointer<CChar> {}
+
+@_SwiftifyImport(.sizedBy(pointer: .param(2), size: "size"),
+                 .sizedBy(pointer: .return, size: "size"),
+                 .lifetimeDependence(dependsOn: .param(2), pointer: .return, type: .copy))
+func mutReturnDependence(_ size: CInt, _ ptr: UnsafeMutablePointer<UInt8>) -> UnsafeMutablePointer<UInt8> {}
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func constParam(_ ptr: UnsafeRawBufferPointer) {
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe constParam(ptr.baseAddress!.assumingMemoryBound(to: CChar.self), size)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func mutParam(_ ptr: UnsafeMutableRawBufferPointer) {
+// CHECK-NEXT:     let size = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe mutParam(ptr.baseAddress!.assumingMemoryBound(to: UInt8.self), size)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func exprParam(_ ptr: UnsafeMutableRawBufferPointer, _ size: CInt, _ count: CInt) {
+// CHECK-NEXT:     let _ptrCount = unsafe ptr.count
+// CHECK-NEXT:     if _ptrCount != size * count {
+// CHECK-NEXT:       fatalError("bounds check failure in exprParam: expected \(size * count) but got \(_ptrCount)")
+// CHECK-NEXT:     }
+// CHECK-NEXT:     return unsafe exprParam(ptr.baseAddress!.assumingMemoryBound(to: UInt8.self), size, count)
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func constReturn(_ size: CInt) -> UnsafeRawBufferPointer {
+// CHECK-NEXT:     return unsafe UnsafeRawBufferPointer(start: unsafe constReturn(size), count: Int(size))
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func mutReturn(_ size: CInt) -> UnsafeMutableRawBufferPointer {
+// CHECK-NEXT:     return unsafe UnsafeMutableRawBufferPointer(start: unsafe mutReturn(size), count: Int(size))
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func exprReturn(_ size: CInt, _ count: CInt) -> UnsafeMutableRawBufferPointer {
+// CHECK-NEXT:     return unsafe UnsafeMutableRawBufferPointer(start: unsafe exprReturn(size, count), count: Int(size * count))
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
+// CHECK-NEXT: func constParamNoreturn(_ ptr: RawSpan) {
+// CHECK-NEXT:     let size = CInt(exactly: ptr.byteCount)!
+// CHECK-NEXT:     return unsafe ptr.withUnsafeBytes { _ptrPtr in
+// CHECK-NEXT:       return unsafe constParamNoreturn(_ptrPtr.baseAddress!.assumingMemoryBound(to: CChar.self), size)
+// CHECK-NEXT:     }
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(ptr: copy ptr) @_disfavoredOverload
+// CHECK-NEXT: func mutParamNoreturn(_ ptr: inout MutableRawSpan) {
+// CHECK-NEXT:     let size = CInt(exactly: ptr.byteCount)!
+// CHECK-NEXT:     return unsafe ptr.withUnsafeMutableBytes { _ptrPtr in
+// CHECK-NEXT:       return unsafe mutParamNoreturn(_ptrPtr.baseAddress!.assumingMemoryBound(to: UInt8.self), size)
+// CHECK-NEXT:     }
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy ptr) @_disfavoredOverload
+// CHECK-NEXT: func constReturnDependence(_ ptr: RawSpan) -> RawSpan {
+// CHECK-NEXT:     let size = CInt(exactly: ptr.byteCount)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(RawSpan(_unsafeStart: unsafe ptr.withUnsafeBytes { _ptrPtr in
+// CHECK-NEXT:       return unsafe constReturnDependence(size, _ptrPtr.baseAddress!.assumingMemoryBound(to: UInt8.self))
+// CHECK-NEXT:             }, byteCount: Int(size)), copying: ())
+// CHECK-NEXT: }
+
+// CHECK:      @_alwaysEmitIntoClient @_lifetime(copy ptr) @_lifetime(ptr: copy ptr) @_disfavoredOverload
+// CHECK-NEXT: func mutReturnDependence(_ ptr: inout MutableRawSpan) -> MutableRawSpan {
+// CHECK-NEXT:     let size = CInt(exactly: ptr.byteCount)!
+// CHECK-NEXT:     return unsafe _swiftifyOverrideLifetime(MutableRawSpan(_unsafeStart: unsafe ptr.withUnsafeMutableBytes { _ptrPtr in
+// CHECK-NEXT:       return unsafe mutReturnDependence(size, _ptrPtr.baseAddress!.assumingMemoryBound(to: UInt8.self))
+// CHECK-NEXT:             }, byteCount: Int(size)), copying: ())
+// CHECK-NEXT: }
diff --git a/test/Macros/SwiftifyImport/SizedBy/Unwrapped.swift b/test/Macros/SwiftifyImport/SizedBy/Unwrapped.swift
index c18be3ae42f62..15ba4616a586f 100644
--- a/test/Macros/SwiftifyImport/SizedBy/Unwrapped.swift
+++ b/test/Macros/SwiftifyImport/SizedBy/Unwrapped.swift
@@ -6,8 +6,8 @@
 func myFunc(_ ptr: UnsafeRawPointer!, _ len: CInt) {
 }
 
-// CHECK:      @_alwaysEmitIntoClient
+// CHECK:      @_alwaysEmitIntoClient @_disfavoredOverload
 // CHECK-NEXT: func myFunc(_ ptr: UnsafeRawBufferPointer) {
-// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, CInt(exactly: ptr.count)!)
+// CHECK-NEXT:     let len = CInt(exactly: unsafe ptr.count)!
+// CHECK-NEXT:     return unsafe myFunc(ptr.baseAddress!, len)
 // CHECK-NEXT: }
-
diff --git a/test/Macros/accessor_macros.swift b/test/Macros/accessor_macros.swift
index e9da34f84fa0e..d64f91be11702 100644
--- a/test/Macros/accessor_macros.swift
+++ b/test/Macros/accessor_macros.swift
@@ -4,7 +4,7 @@
 // RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift -g -no-toolchain-stdlib-rpath
 
 // Check for expected errors.
-// RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -DTEST_DIAGNOSTICS -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -DTEST_DIAGNOSTICS -verify-ignore-unknown
 // RUN: not %target-swift-frontend -typecheck -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -DTEST_DIAGNOSTICS %s > %t/diags.txt 2>&1
 // RUN: %FileCheck -check-prefix=CHECK-DIAGS %s < %t/diags.txt
 
@@ -99,6 +99,11 @@ struct MyBrokenStruct {
   // expected-note@+1 2{{in expansion of macro 'myPropertyWrapper' on property 'birthDate' here}}
   @myPropertyWrapper
   var birthDate: Date? {
+    /*
+    expected-expansion@-2:25{{
+      expected-error@1:1{{variable already has a getter}}
+    }}
+    */
     // CHECK-DIAGS: variable already has a getter
     // CHECK-DIAGS: in expansion of macro
     // CHECK-DIAGS: previous definition of getter here
@@ -153,6 +158,12 @@ struct HasStoredTests {
   // expected-error@-1{{expansion of macro 'MakeComputedSneakily()' produced an unexpected getter}}
   // expected-note@-2 2{{in expansion of macro}}
   // expected-note@-3 2{{'z' declared here}}
+  /*
+     expected-expansion@-5:36{{
+       expected-error@3:9{{cannot find '_z' in scope; did you mean 'z'?}}
+       expected-error@6:9{{cannot find '_z' in scope; did you mean 'z'?}}
+     }}
+  */
 #endif
 }
 
diff --git a/test/Macros/attached_macros_diags.swift b/test/Macros/attached_macros_diags.swift
index 52ef735e7262e..d123e351771d4 100644
--- a/test/Macros/attached_macros_diags.swift
+++ b/test/Macros/attached_macros_diags.swift
@@ -2,7 +2,7 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -parse-as-library -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift -g -no-toolchain-stdlib-rpath
-// RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -disable-availability-checking -module-name MacrosTest
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -disable-availability-checking -module-name MacrosTest
 
 @attached(peer) macro m1() = #externalMacro(module: "MacroDefinition", type: "EmptyPeerMacro")
 
diff --git a/test/Macros/bind_extensions_request_cycle.swift b/test/Macros/bind_extensions_request_cycle.swift
new file mode 100644
index 0000000000000..8454b27b6b345
--- /dev/null
+++ b/test/Macros/bind_extensions_request_cycle.swift
@@ -0,0 +1,29 @@
+// RUN: %target-typecheck-verify-swift %s
+
+@attached(member) @attached(peer)
+public macro Foo(_: any P) = #externalMacro(module: "FooMacros", type: "FooMacro")
+// expected-warning@-1 {{external macro implementation type 'FooMacros.FooMacro' could not be found for macro 'Foo'; plugin for module 'FooMacros' not found}}
+// expected-note@-2 2 {{'Foo' declared here}}
+
+public protocol P {}
+
+@Foo(S.s)
+struct A {
+// expected-error@-1 2 {{external macro implementation type 'FooMacros.FooMacro' could not be found for macro 'Foo'; plugin for module 'FooMacros' not found}}
+  func a() {}
+}
+
+extension A {
+  struct Nested {}
+}
+
+// Binding this extension must not trigger macro expansion, because that
+// performs a qualified lookup of S.s, which fails because the extension
+// of P declared below has not been bound yet.
+extension A.Nested {}
+
+struct S: P {}
+
+extension P where Self == S {
+  static var s: Self { Self() }
+}
diff --git a/test/Macros/default_main_actor_nonisolated.swift b/test/Macros/default_main_actor_nonisolated.swift
new file mode 100644
index 0000000000000..7492d9b63aa52
--- /dev/null
+++ b/test/Macros/default_main_actor_nonisolated.swift
@@ -0,0 +1,25 @@
+// REQUIRES: swift_swift_parser, executable_test
+
+// RUN: %empty-directory(%t)
+// RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift -g -no-toolchain-stdlib-rpath
+
+// Check for errors
+// RUN: %target-swift-frontend -swift-version 5 -typecheck -load-plugin-library %t/%target-library-name(MacroDefinition) %s -I %t -disable-availability-checking -swift-version 6 -default-isolation MainActor
+
+@attached(extension, conformances: Sendable)
+macro AddSendable() = #externalMacro(module: "MacroDefinition", type: "SendableMacro")
+
+@AddSendable
+final class SendableClass {
+  var property: Int { 0 }
+
+  func f() { }
+}
+
+nonisolated func acceptSendable<T: Sendable>(_: T) { }
+
+@concurrent func test(sc: SendableClass) async {
+  acceptSendable(sc) // SendableClass is Sendable
+  acceptSendable(\SendableClass.property) // so is its property
+  sc.f() // not on the main actor, so this is okay
+}
diff --git a/test/Macros/expand_on_imported.swift b/test/Macros/expand_on_imported.swift
index 3ae05b8a872c2..7c524da930df7 100644
--- a/test/Macros/expand_on_imported.swift
+++ b/test/Macros/expand_on_imported.swift
@@ -1,4 +1,4 @@
-// REQUIRES: swift_swift_parser, executable_test, concurrency
+// REQUIRES: swift_swift_parser, concurrency, string_processing
 // REQUIRES: swift_feature_MacrosOnImports
 
 // RUN: %empty-directory(%t)
diff --git a/test/Macros/expand_on_imported_objc.swift b/test/Macros/expand_on_imported_objc.swift
index d4a9258c40cdd..45b0d6814e608 100644
--- a/test/Macros/expand_on_imported_objc.swift
+++ b/test/Macros/expand_on_imported_objc.swift
@@ -1,4 +1,4 @@
-// REQUIRES: swift_swift_parser, executable_test, objc_interop, concurrency
+// REQUIRES: swift_swift_parser, objc_interop, concurrency, string_processing
 // REQUIRES: swift_feature_MacrosOnImports
 // REQUIRES: OS=macosx
 
@@ -9,7 +9,7 @@
 // RUN: %target-swift-frontend -swift-version 5 -emit-module -o %t/macro_library.swiftmodule %S/Inputs/macro_library.swift -module-name macro_library -load-plugin-library %t/%target-library-name(MacroDefinition)
 
 // Diagnostics testing
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -swift-version 5 -enable-experimental-feature MacrosOnImports -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name ModuleUser %s -I %t -DTEST_DIAGNOSTICS
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated -swift-version 5 -enable-experimental-feature MacrosOnImports -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name ModuleUser %s -I %t -DTEST_DIAGNOSTICS
 
 // Emit IR just to make sure nothing else fails.
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-ir -swift-version 5 -g -enable-experimental-feature MacrosOnImports -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name ModuleUser %s -I %t | %FileCheck %s
diff --git a/test/Macros/expand_peers_hang.swift b/test/Macros/expand_peers_hang.swift
index 5e9a0a7ad1698..10d7f974cf02e 100644
--- a/test/Macros/expand_peers_hang.swift
+++ b/test/Macros/expand_peers_hang.swift
@@ -2,7 +2,7 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -parse-as-library -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift -g -no-toolchain-stdlib-rpath
-// RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -parse-as-library -disable-availability-checking
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -parse-as-library -disable-availability-checking
 
 @attached(peer, names: named(BadThing))
 macro HangingMacro() = #externalMacro(module: "MacroDefinition", type: "HangingMacro")
diff --git a/test/Macros/external-macro-without-decl.swift b/test/Macros/external-macro-without-decl.swift
index 532cf21ab07d0..3bfcf05a13480 100644
--- a/test/Macros/external-macro-without-decl.swift
+++ b/test/Macros/external-macro-without-decl.swift
@@ -2,7 +2,7 @@
 
 // RUN: %target-typecheck-verify-swift -swift-version 5 -module-name Swift -parse-stdlib
 
-// expected-warning@+2{{@expression has been removed in favor of @freestanding(expression)}}
+// expected-warning@+2{{'@expression' has been removed in favor of '@freestanding(expression)'}}
 // expected-warning@+1{{external macro implementation type 'A.B' could not be found for macro 'myMacro()'}}
 @expression macro myMacro() = #externalMacro(module: "A", type: "B")
 
diff --git a/test/Macros/imported_type_error.swift b/test/Macros/imported_type_error.swift
new file mode 100644
index 0000000000000..c58734f7635f1
--- /dev/null
+++ b/test/Macros/imported_type_error.swift
@@ -0,0 +1,20 @@
+// REQUIRES: swift_swift_parser, string_processing
+// REQUIRES: swift_feature_MacrosOnImports
+
+// RUN: %empty-directory(%t)
+// RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift -g -no-toolchain-stdlib-rpath -swift-version 5
+
+// Build the macro library to give us access to ExpandTypeError.
+// RUN: %target-swift-frontend -swift-version 5 -emit-module -o %t/macro_library.swiftmodule %S/Inputs/macro_library.swift -module-name macro_library -load-plugin-library %t/%target-library-name(MacroDefinition)
+
+// FIXME: we should typecheck these macro expansions before silgen
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -swift-version 5 -enable-experimental-feature MacrosOnImports -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name ErrorModuleUser %s -I %t
+
+// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-module -swift-version 5 -enable-experimental-feature MacrosOnImports -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name ErrorModuleUser %s -I %t 2>&1 | %FileCheck %s
+
+import ImportedMacroError
+import macro_library
+
+foo(42)
+
+// CHECK: error: cannot find 'callToMissingFunction' in scope
diff --git a/test/Macros/issue-80835.swift b/test/Macros/issue-80835.swift
new file mode 100644
index 0000000000000..863e988ea6e34
--- /dev/null
+++ b/test/Macros/issue-80835.swift
@@ -0,0 +1,84 @@
+// RUN: %empty-directory(%t)
+// RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift
+
+// RUN: %target-typecheck-verify-swift -swift-version 6 -load-plugin-library %t/%target-library-name(MacroDefinition) -verify-additional-prefix swift6-
+// RUN: %target-typecheck-verify-swift -swift-version 7 -load-plugin-library %t/%target-library-name(MacroDefinition) -verify-additional-prefix swift7-
+
+// REQUIRES: swift_swift_parser
+// REQUIRES: swift7
+
+// https://github.com/swiftlang/swift/issues/80835
+
+@available(*, noasync)
+func noasyncFn() {}
+
+@_unavailableFromAsync
+func unavailableFromAsyncFn() {} // expected-note {{'unavailableFromAsyncFn()' declared here}}
+
+@freestanding(expression)
+macro asyncMacro(_ fn: () async -> Void) = #externalMacro(module: "MacroDefinition", type: "GenericToVoidMacro")
+
+@freestanding(declaration)
+macro asyncMacroDecl(_ fn: () async -> Void) = #externalMacro(module: "MacroDefinition", type: "EmptyDeclarationMacro")
+
+@attached(peer)
+macro AsyncMacro(_ fn: () async -> Void) = #externalMacro(module: "MacroDefinition", type: "WrapperMacro")
+
+func takesAsyncFn(_ fn: () async -> Void) {}
+
+#asyncMacro {
+  defer {
+    noasyncFn()
+    // expected-swift7-error@-1 {{global function 'noasyncFn' is unavailable from asynchronous contexts}}
+    // expected-swift6-warning@-2 {{global function 'noasyncFn' is unavailable from asynchronous contexts; this will be an error in a future Swift language mode}}
+  }
+  noasyncFn()
+  // expected-swift7-error@-1 {{global function 'noasyncFn' is unavailable from asynchronous contexts}}
+  // expected-swift6-warning@-2 {{global function 'noasyncFn' is unavailable from asynchronous contexts; this will be an error in a future Swift language mode}}
+
+  unavailableFromAsyncFn()
+  // expected-swift7-error@-1 {{global function 'unavailableFromAsyncFn' is unavailable from asynchronous contexts}}
+  // expected-swift6-warning@-2 {{global function 'unavailableFromAsyncFn' is unavailable from asynchronous contexts; this will be an error in a future Swift language mode}}
+
+  // This was always an error.
+  let _: () async -> Void = {
+    noasyncFn()
+    // expected-error@-1 {{global function 'noasyncFn' is unavailable from asynchronous contexts}}
+  }
+}
+
+// This was always an error.
+takesAsyncFn {
+  noasyncFn()
+  // expected-error@-1 {{global function 'noasyncFn' is unavailable from asynchronous contexts}}
+}
+
+#asyncMacroDecl {
+  noasyncFn()
+  // expected-swift7-error@-1 {{global function 'noasyncFn' is unavailable from asynchronous contexts}}
+  // expected-swift6-warning@-2 {{global function 'noasyncFn' is unavailable from asynchronous contexts; this will be an error in a future Swift language mode}}
+}
+
+typealias Magic<T> = T
+
+// expected-swift7-error@+2 {{global function 'noasyncFn' is unavailable from asynchronous contexts}}
+// expected-swift6-warning@+1 {{global function 'noasyncFn' is unavailable from asynchronous contexts; this will be an error in a future Swift language mode}}
+@AsyncMacro({ noasyncFn() })
+func foo() {
+  #asyncMacro(({
+    noasyncFn()
+    // expected-swift7-error@-1 {{global function 'noasyncFn' is unavailable from asynchronous contexts}}
+    // expected-swift6-warning@-2 {{global function 'noasyncFn' is unavailable from asynchronous contexts; this will be an error in a future Swift language mode}}
+  }))
+
+  #asyncMacroDecl(({
+    noasyncFn()
+    // expected-swift7-error@-1 {{global function 'noasyncFn' is unavailable from asynchronous contexts}}
+    // expected-swift6-warning@-2 {{global function 'noasyncFn' is unavailable from asynchronous contexts; this will be an error in a future Swift language mode}}
+  }))
+
+  // This was never treated as async.
+  #asyncMacro({
+    noasyncFn()
+  } as Magic)
+}
diff --git a/test/Macros/macro_and_typealias.swift b/test/Macros/macro_and_typealias.swift
index fffd8b0fe17a2..bf3c6763b1f02 100644
--- a/test/Macros/macro_and_typealias.swift
+++ b/test/Macros/macro_and_typealias.swift
@@ -9,11 +9,11 @@
 @freestanding(expression) public macro ConcretePrint(_ value: Any) = #externalMacro(module: "MacroDefinition", type: "PrintMacro")
 @freestanding(expression) public macro MultiPrint(_ value: Any) = #externalMacro(module: "MacroDefinition", type: "PrintMacro")
 
-public struct Printer<Value> { // expected-note {{generic type 'Printer' declared here}}
+public struct Printer<Value> { // expected-note {{generic struct 'Printer' declared here}}
   init(_: (Value) -> Void) {}
 }
 
-public struct MultiPrinter<T, U> { // expected-note {{generic type 'MultiPrinter' declared here}}
+public struct MultiPrinter<T, U> { // expected-note {{generic struct 'MultiPrinter' declared here}}
 }
 
 typealias Print = Printer
diff --git a/test/Macros/macro_attribute_expansiondecl.swift b/test/Macros/macro_attribute_expansiondecl.swift
index 0c7ebe34a9967..132f155e136d2 100644
--- a/test/Macros/macro_attribute_expansiondecl.swift
+++ b/test/Macros/macro_attribute_expansiondecl.swift
@@ -100,7 +100,7 @@ public struct FuncFooBarNoAttrsMacro: DeclarationMacro {
 @available(SwiftStdlib 9999, *)
 #globalDecls
 
-func testGlobal() { // expected-note 2 {{add @available attribute to enclosing global function}}
+func testGlobal() { // expected-note 2 {{add '@available' attribute to enclosing global function}}
   globalFunc() // expected-error {{'globalFunc()' is only available in macOS 9999 or newer}} expected-note {{add 'if #available' version check}}
   _ = globalVar // expected-error {{'globalVar' is only available in macOS 9999 or newer}} expected-note {{add 'if #available' version check}}
 }
@@ -109,7 +109,7 @@ struct S {
   @available(SwiftStdlib 9999, *)
   #memberDecls
 }
-func testMember(value: S) { // expected-note 2 {{add @available attribute to enclosing global function}}
+func testMember(value: S) { // expected-note 2 {{add '@available' attribute to enclosing global function}}
   value.memberFunc() // expected-error {{'memberFunc()' is only available in macOS 9999 or newer}} expected-note {{add 'if #available' version check}}
   _ = value.memberVar // expected-error {{'memberVar' is only available in macOS 9999 or newer}} expected-note {{add 'if #available' version check}}
 }
@@ -159,11 +159,20 @@ struct S1 {
 }
 
 // FIXME: Diagnostics could be better.
-struct S2 { // expected-note 4 {{add @available attribute to enclosing struct}}
-  // expected-note@+3 6 {{in expansion of macro 'funcFromClosureMacro' here}}
+struct S2 { // expected-note 4 {{add '@available' attribute to enclosing struct}}
   // expected-error@+2 {{'APIFrom99()' is only available in macOS 99 or newer}}
-  // expected-error@+2 {{'APIFrom99()' is only available in macOS 99 or newer}} expected-note@+2 {{add 'if #available' version check}}
+  // expected-error@+12 {{'APIFrom99()' is only available in macOS 99 or newer}} expected-note@+12 {{add 'if #available' version check}}
   #funcFromClosureMacro(APIFrom99()) {
+    /*
+    expected-note@-2 6 {{in expansion of macro 'funcFromClosureMacro' here}}
+    expected-expansion@-3:3{{
+      expected-note@1:6 2{{add '@available' attribute to enclosing instance method}}
+      expected-error@2:9{{'APIFrom99()' is only available in macOS 99 or newer}}
+      expected-note@2:9{{add 'if #available' version check}}
+      expected-error@14:11{{'APIFrom99()' is only available in macOS 99 or newer}}
+      expected-note@14:11{{add 'if #available' version check}}
+    }}
+    */
     _ = APIFrom99()
     if #available(macOS 999, *) {
       _ = APIFrom99()
diff --git a/test/Macros/macro_availability_macosx.swift b/test/Macros/macro_availability_macosx.swift
index ecfc7b66adfd8..0f4c695eed0ed 100644
--- a/test/Macros/macro_availability_macosx.swift
+++ b/test/Macros/macro_availability_macosx.swift
@@ -10,7 +10,7 @@ struct X { }
 
 @freestanding(expression) macro m1() -> X = #externalMacro(module: "A", type: "B") // expected-error{{'X' is only available in macOS 12.0 or newer}}
 // expected-warning@-1{{external macro implementation type 'A.B' could not be found for macro 'm1()'}}
-// expected-note@-2{{add @available attribute to enclosing macro}}
+// expected-note@-2{{add '@available' attribute to enclosing macro}}
 
 @available(macOS 12.0, *)
 @freestanding(expression) macro m2() -> X = #externalMacro(module: "A", type: "B")
diff --git a/test/Macros/macro_build_config.swift b/test/Macros/macro_build_config.swift
new file mode 100644
index 0000000000000..2a1083ef3fb9d
--- /dev/null
+++ b/test/Macros/macro_build_config.swift
@@ -0,0 +1,17 @@
+// REQUIRES: swift_swift_parser, executable_test
+
+// RUN: %empty-directory(%t)
+// RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift
+
+// Execution testing
+// RUN: %target-build-swift -swift-version 5 -g -load-plugin-library %t/%target-library-name(MacroDefinition) %s -o %t/main -module-name MacroUser -Xfrontend -emit-dependencies-path -Xfrontend %t/main.d -Xfrontend -emit-reference-dependencies-path -Xfrontend %t/main.swiftdeps -DDEBUG
+// RUN: %target-codesign %t/main
+// RUN: %target-run %t/main | %FileCheck %s
+
+@freestanding(expression) macro isCustomConditionSet(_ name: String) -> Bool = #externalMacro(module: "MacroDefinition", type: "CustomConditionCheckMacro")
+
+// CHECK: Release = false
+print("Release = \(#isCustomConditionSet("RELEASE"))")
+
+// CHECK: Debug = true
+print("Debug = \(#isCustomConditionSet("DEBUG"))")
diff --git a/test/Macros/macro_expand.swift b/test/Macros/macro_expand.swift
index 8d7fbf3c36c00..128463e5d4051 100644
--- a/test/Macros/macro_expand.swift
+++ b/test/Macros/macro_expand.swift
@@ -4,13 +4,13 @@
 // RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift
 
 // Diagnostics testing
-// RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser -DTEST_DIAGNOSTICS
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser -DTEST_DIAGNOSTICS
 
 // Diagnostics testing by importing macros from a module
 // RUN: %target-swift-frontend -swift-version 5 -emit-module -o %t/freestanding_macro_library.swiftmodule %S/Inputs/freestanding_macro_library.swift -module-name freestanding_macro_library -load-plugin-library %t/%target-library-name(MacroDefinition)
 // RUN: %target-swift-frontend -swift-version 5 -emit-module -o %t/freestanding_macro_library_2.swiftmodule %S/Inputs/freestanding_macro_library_2.swift -module-name freestanding_macro_library_2 -load-plugin-library %t/%target-library-name(MacroDefinition) -I %t
 
-// RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser -DTEST_DIAGNOSTICS -I %t -DIMPORT_MACRO_LIBRARY
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser -DTEST_DIAGNOSTICS -I %t -DIMPORT_MACRO_LIBRARY
 
 // RUN: not %target-swift-frontend -swift-version 5 -typecheck -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser -DTEST_DIAGNOSTICS -serialize-diagnostics-path %t/macro_expand.dia %s -emit-macro-expansion-files no-diagnostics -Rmacro-loading > %t/macro-printing.txt
 // RUN: c-index-test -read-diagnostics %t/macro_expand.dia 2>&1 | %FileCheck -check-prefix CHECK-DIAGS -dump-input=always %s
@@ -63,6 +63,9 @@ macro freestandingWithClosure<T>(_ value: T, body: (T) -> T) = #externalMacro(mo
 
 #endif
 
+@freestanding(declaration, names: named(storedProperty))
+public macro AddStoredProperty<T>(_ x: T) = #externalMacro(module: "MacroDefinition", type: "StoredPropertyMacro")
+
 #if TEST_DIAGNOSTICS
 @freestanding(declaration)
 macro NotCovered() = #externalMacro(module: "MacroDefinition", type: "InvalidMacro")
@@ -70,11 +73,11 @@ macro NotCovered() = #externalMacro(module: "MacroDefinition", type: "InvalidMac
 struct MemberNotCovered {
   #NotCovered
   // expected-note@-1 {{in expansion of macro 'NotCovered' here}}
-
-  // CHECK-DIAGS: error: declaration name 'value' is not covered by macro 'NotCovered'
-  // CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser0023macro_expandswift_elFCffMX70_2_33_4361AD9339943F52AE6186DD51E04E91Ll10NotCoveredfMf_.swift
-  // CHECK-DIAGS: var value: Int
-  // CHECK-DIAGS: END CONTENTS OF FILE
+  /*
+  expected-expansion@-3:3 {{
+    expected-error@1:5{{declaration name 'value' is not covered by macro 'NotCovered'}}
+  }}
+  */
 }
 
 @attached(peer)
@@ -83,24 +86,29 @@ macro Invalid() = #externalMacro(module: "MacroDefinition", type: "InvalidMacro"
 @Invalid
 struct Bad {}
 // expected-note@-2 18 {{in expansion of macro 'Invalid' on struct 'Bad' here}}
+/*
+expected-expansion@-3:14 {{
+  expected-error@1:8{{macro expansion cannot introduce import}}
+  expected-error@3:17{{macro expansion cannot introduce precedence group}}
+  expected-error@6:25{{macro 'myMacro()' requires a definition}}
+  expected-error@6:25{{macro expansion cannot introduce macro}}
+  expected-error@8:1{{macro expansion cannot introduce extension}}
+  expected-error@11:1{{macro expansion cannot introduce '@main' type}}
+  expected-error@12:8{{declaration name 'MyMain' is not covered by macro 'Invalid'}}
+  expected-error@17:11{{declaration name 'Array' is not covered by macro 'Invalid'}}
+  expected-error@19:11{{declaration name 'Dictionary' is not covered by macro 'Invalid'}}
+  expected-error@21:11{{macro expansion cannot introduce default literal type 'BooleanLiteralType'}}
+  expected-error@23:11{{macro expansion cannot introduce default literal type 'ExtendedGraphemeClusterType'}}
+  expected-error@25:11{{macro expansion cannot introduce default literal type 'FloatLiteralType'}}
+  expected-error@27:11{{macro expansion cannot introduce default literal type 'IntegerLiteralType'}}
+  expected-error@29:11{{macro expansion cannot introduce default literal type 'StringLiteralType'}}
+  expected-error@31:11{{macro expansion cannot introduce default literal type 'UnicodeScalarType'}}
+  expected-error@33:11{{macro expansion cannot introduce default literal type '_ColorLiteralType'}}
+  expected-error@35:11{{macro expansion cannot introduce default literal type '_ImageLiteralType'}}
+  expected-error@37:11{{macro expansion cannot introduce default literal type '_FileReferenceLiteralType'}}
+}}
+*/
 
-// CHECK-DIAGS: error: macro expansion cannot introduce import
-// CHECK-DIAGS: error: macro expansion cannot introduce precedence group
-// CHECK-DIAGS: error: macro expansion cannot introduce macro
-// CHECK-DIAGS: error: macro expansion cannot introduce extension
-// CHECK-DIAGS: error: macro expansion cannot introduce '@main' type
-// CHECK-DIAGS: error: declaration name 'MyMain' is not covered by macro 'Invalid'
-// CHECK-DIAGS: error: declaration name 'Array' is not covered by macro 'Invalid'
-// CHECK-DIAGS: error: declaration name 'Dictionary' is not covered by macro 'Invalid'
-// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'BooleanLiteralType'
-// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'ExtendedGraphemeClusterType'
-// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'FloatLiteralType'
-// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'IntegerLiteralType'
-// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'StringLiteralType'
-// CHECK-DIAGS: error: macro expansion cannot introduce default literal type 'UnicodeScalarType'
-// CHECK-DIAGS: error: macro expansion cannot introduce default literal type '_ColorLiteralType'
-// CHECK-DIAGS: error: macro expansion cannot introduce default literal type '_ImageLiteralType'
-// CHECK-DIAGS: error: macro expansion cannot introduce default literal type '_FileReferenceLiteralType'
 
 // CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser3Bad7InvalidfMp_.swift
 // CHECK-DIAGS: import Swift
@@ -126,6 +134,56 @@ struct Bad {}
 // CHECK-DIAGS: typealias _ImageLiteralType = Void
 // CHECK-DIAGS: typealias _FileReferenceLiteralType = Void
 // CHECK-DIAGS: END CONTENTS OF FILE
+
+class HasStoredPropertyClassInvalid {
+  #AddStoredProperty((Self.self, 0).1) // expected-note {{in expansion of macro 'AddStoredProperty' here}}
+  /*
+  expected-expansion@-2:3 {{
+    expected-error@1:22{{covariant 'Self' type cannot be referenced from a stored property initializer}}
+  }}
+  */
+}
+
+// Redeclaration checking should behave as though expansions are part of the
+// source file.
+struct RedeclChecking {
+  #varValue
+  /*
+  expected-expansion@-2:3 {{
+    expected-note@1:5{{'value' previously declared here}}
+  }}
+  */
+
+  // expected-error@+1 {{invalid redeclaration of 'value'}}
+  var value: Int { 0 }
+}
+
+// CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser0023macro_expandswift_elFCffMX[[@LINE-12]]_2_33_4361AD9339943F52AE6186DD51E04E91Ll8varValuefMf_.swift:
+// CHECK-DIAGS: var value: Int {
+// CHECK-DIAGS:     1
+// CHECK-DIAGS: }
+// CHECK-DIAGS: END CONTENTS OF FILE
+
+@attached(body)
+public macro ThrowCancellation() = #externalMacro(module: "MacroDefinition", type: "ThrowCancellationMacro")
+
+// https://github.com/swiftlang/swift/issues/79039 - Make sure we diagnose the
+// error mismatch.
+@ThrowCancellation // expected-note {{in expansion of macro 'ThrowCancellation' on global function 'issue79039()' here}}
+func issue79039() throws(DecodingError)
+/*
+expected-expansion@-2:39 {{
+  expected-error@2:11{{thrown expression type 'CancellationError' cannot be converted to error type 'DecodingError'}}
+}}
+*/
+
+@ThrowCancellation // expected-note {{in expansion of macro 'ThrowCancellation' on global function 'issue79039_2()' here}}
+func issue79039_2() throws(DecodingError) {}
+/*
+expected-expansion@-2:43 {{
+  expected-error@2:11{{thrown expression type 'CancellationError' cannot be converted to error type 'DecodingError'}}
+}}
+*/
 #endif
 
 @freestanding(declaration)
@@ -138,18 +196,28 @@ macro AccidentalCodeItem() = #externalMacro(module: "MacroDefinition", type: "Fa
 func invalidDeclarationMacro() {
   #accidentalCodeItem
   // expected-note@-1 {{in expansion of macro 'accidentalCodeItem' here}}
-  // CHECK-DIAGS: @__swiftmacro_9MacroUser0023macro_expandswift_elFCffMX138_2_18accidentalCodeItemfMf_.swift:1:1: error: expected macro expansion to produce a declaration
+  /*
+  expected-expansion@-3:3 {{
+    expected-error@1:1{{expected macro expansion to produce a declaration}}
+  }}
+  */
 
   @AccidentalCodeItem struct S {}
   // expected-note@-1 {{in expansion of macro 'AccidentalCodeItem' on struct 'S' here}}
-  // CHECK-DIAGS: @__swiftmacro_9MacroUser018invalidDeclarationA0yyF5S_$l0L_18AccidentalCodeItemfMp_.swift:1:1: error: expected macro expansion to produce a declaration
-
-  struct LocalThing1 {
-    func f() {
-      #accidentalCodeItem
-      // expected-note@-1 {{in expansion of macro 'accidentalCodeItem' here}}
-      // CHECK-DIAGS: @__swiftmacro_9MacroUser018invalidDeclarationA0yyF5S_$l0L_18AccidentalCodeItemfMp_.swift
-    }
+  /*
+  expected-expansion@-3:34 {{
+    expected-error@1:1{{expected macro expansion to produce a declaration}}
+  }}
+  */
+
+  do {
+    @AccidentalCodeItem struct S {}
+    // expected-note@-1 {{in expansion of macro 'AccidentalCodeItem' on struct 'S' here}}
+    /*
+    expected-expansion@-3:36 {{
+      expected-error@1:1{{expected macro expansion to produce a declaration}}
+    }}
+    */
   }
 }
 #endif
@@ -287,9 +355,14 @@ func testNested() {
   struct Nested { }
   _ = #stringify(#assertAny(Nested()))
   // expected-note@-1 {{in expansion of macro 'stringify' here}}
-// CHECK-DIAGS-NOT: error: cannot convert value of type 'Nested' to expected argument type 'Bool'
-// CHECK-DIAGS: @__swiftmacro_9MacroUser0023macro_expandswift_elFCffMX{{.*}}_9stringifyfMf_9assertAnyfMf_.swift:1:8: error: cannot convert value of type 'Nested' to expected argument type 'Bool'
-// CHECK-DIAGS-NOT: error: cannot convert value of type 'Nested' to expected argument type 'Bool'
+  /*
+  expected-expansion@-3:7 {{
+    expected-note@1:2{{in expansion of macro 'assertAny' here}}
+    expected-expansion@1:2{{
+      expected-error@1:8{{cannot convert value of type 'Nested' to expected argument type 'Bool'}}
+    }}
+  }}
+  */
 
   // PRETTY-DIAGS: 1:8: error: cannot convert value of type 'Nested' to expected argument type 'Bool'
   // PRETTY-DIAGS: macro_expand.swift:{{.*}}:39: note: expanded code originates here
@@ -308,8 +381,15 @@ func testStringifyWithThrows() throws {
 #if TEST_DIAGNOSTICS
   // FIXME: Lots of duplicate notes here
   _ = #stringify(maybeThrowing()) // expected-note 4{{in expansion of macro 'stringify' here}}
+  /*
+  expected-expansion@-2:7 {{
+    expected-error@1:2{{call can throw but is not marked with 'try'}}
+    expected-note@1:2{{did you mean to disable error propagation?}}
+    expected-note@1:2{{did you mean to handle error as optional value?}}
+    expected-note@1:2{{did you mean to use 'try'?}}
+  }}
+  */
 
-    // CHECK-DIAGS: @__swiftmacro_9MacroUser0023macro_expandswift_elFCffMX{{.*}}_9stringifyfMf1_.swift:1:2: error: call can throw but is not marked with 'try'
 #endif
 
   // The macro adds the 'try' for us.
@@ -349,14 +429,18 @@ func testAddBlocker(a: Int, b: Int, c: Int, oa: OnlyAdds) {
   _ = #addBlocker(oa + oa) // expected-error{{blocked an add; did you mean to subtract? (from macro 'addBlocker')}}
   // expected-note@-1{{in expansion of macro 'addBlocker' here}}
   // expected-note@-2{{use '-'}}{{22-23=-}}
-
-  // CHECK-DIAGS: @__swiftmacro_9MacroUser0023macro_expandswift_elFCffMX{{.*}}_10addBlockerfMf1_.swift:1:4: error: binary operator '-' cannot be applied to two 'OnlyAdds' operands [] []
-  // CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser0023macro_expandswift_elFCffMX{{.*}}_10addBlockerfMf1_.swift:
-  // CHECK-DIAGS-NEXT: Original source range: {{.*}}macro_expand.swift:[[@LINE-6]]:7 - {{.*}}macro_expand.swift:[[@LINE-6]]:27
-  // CHECK-DIAGS-NEXT: oa - oa
-  // CHECK-DIAGS-NEXT: END CONTENTS OF FILE
+  /*
+  expected-expansion@-4:7 {{
+    expected-error@1:4{{binary operator '-' cannot be applied to two 'OnlyAdds' operands}}
+  }}
+  */
 
   _ = #addBlocker({ // expected-note{{in expansion of macro 'addBlocker' here}}
+  /*
+  expected-expansion@-2:7 {{
+    expected-error@9:16{{referencing operator function '-' on 'FloatingPoint' requires that 'OnlyAdds' conform to 'FloatingPoint'}}
+  }}
+  */
 
       print("hello")
       print(oa + oa) // expected-error{{blocked an add; did you mean to subtract? (from macro 'addBlocker')}}
@@ -367,7 +451,13 @@ func testAddBlocker(a: Int, b: Int, c: Int, oa: OnlyAdds) {
 
   // Check recursion.
   #recurse(false) // okay
-  #recurse(true) // expected-note{{in expansion of macro 'recurse' here}}
+  #recurse(true)
+  /*
+  expected-expansion@-2:3 {{
+    expected-error@1:1{{recursive expansion of macro 'recurse'}}
+  }}
+  expected-note@-5{{in expansion of macro 'recurse' here}}
+  */
 #endif
 }
 
@@ -458,6 +548,14 @@ func testFreestandingMacroExpansion() {
   struct Foo3 {
     #bitwidthNumberedStructs("BUG", blah: false)
     // expected-note@-1 4{{in expansion of macro 'bitwidthNumberedStructs' here}}
+    /*
+    expected-expansion@-3:5 {{
+      expected-error@3:14{{unexpected non-void return value in void function}}
+      expected-note@3:14{{did you mean to add a return type?}}
+      expected-error@6:14{{unexpected non-void return value in void function}}
+      expected-note@6:14{{did you mean to add a return type?}}
+    }}
+    */
     // CHECK-DIAGS: CONTENTS OF FILE @__swiftmacro_9MacroUser0023macro_expandswift_elFCffMX{{.*}}_23bitwidthNumberedStructsfMf_.swift
     // CHECK-DIAGS: struct BUG {
     // CHECK-DIAGS:   func $s9MacroUser0023macro_expandswift_elFCffMX{{.*}}_23bitwidthNumberedStructsfMf_6methodfMu_()
@@ -648,6 +746,69 @@ struct HasNestedType {
   #DefineComparableType
 }
 
+@attached(accessor)
+macro AddGetter() = #externalMacro(module: "MacroDefinition", type: "AddGetterMacro")
+
+// Make sure the mangling for the accessor macro doesn't kick local
+// discriminator assignment, which would miss the autoclosure.
+func testLocalAccessorMacroWithAutoclosure() {
+  @AddGetter
+  var x: Int = 2
+
+  func takesAutoclosure(_ x: @autoclosure () -> Int) {}
+  takesAutoclosure(1)
+}
+
+@propertyWrapper
+struct SomePropertyWrapper<T> {
+  var wrappedValue: T
+  init(wrappedValue: T) {
+    self.wrappedValue = wrappedValue
+  }
+  init(projectedValue: Self) {
+    self = projectedValue
+  }
+  var projectedValue: Self { self }
+}
+
+// Property wrappers on macros probably aren't all that useful, but make sure
+// we don't crash.
+@freestanding(expression)
+macro hasPropertyWrapperParam(@SomePropertyWrapper x: Int) = #externalMacro(module: "MacroDefinition", type: "GenericToVoidMacro")
+
+func testPropertyWrapperMacro() {
+  #hasPropertyWrapperParam(x: 0)
+  #hasPropertyWrapperParam($x: .init(wrappedValue: 0))
+}
+
+#if swift(>=1.0) && TEST_DIAGNOSTICS
+// Test that macros can't be used in @abi
+
+struct ABIAttrWithFreestandingMacro1 {
+  // expected-error@+1 {{cannot use pound literal in '@abi'}}
+  @abi(#varValue)
+  #varValue
+  // expected-note@-1 {{in expansion of macro 'varValue' here}}
+  /*
+  expected-expansion@-3:3 {{
+    expected-error@2:6{{cannot use pound literal in '@abi'}}
+  }}
+  */
+}
+
+struct ABIAttrWithFreestandingMacro2 {
+  // expected-error@+1 {{cannot use pound literal in '@abi'}}
+  @abi(#varValue)
+  var value: Int { 0 }
+}
+
+struct ABIAttrWithFreestandingMacro3 {
+  @abi(var value: Int)
+  #varValue
+}
+
+#endif
+
 #if TEST_DIAGNOSTICS
 @freestanding(expression)
 macro missingMacro() = #externalMacro(module: "MacroDefinition", type: "BluhBlah")
@@ -655,4 +816,30 @@ macro missingMacro() = #externalMacro(module: "MacroDefinition", type: "BluhBlah
 @freestanding(expression)
 macro notMacro() = #externalMacro(module: "MacroDefinition", type: "NotMacroStruct")
 // FIXME: xpected-warning@-1 {{macro implementation type 'MacroDefinition.NotMacroStruct' could not be found for macro 'notMacro()'; 'MacroDefinition.NotMacroStruct' is not a valid macro implementation type in library plugin '}}
+
+// Because this is a method in a local decl, it ends up getting delayed, so
+// we need to check it at the end of the file.
+// FIXME: We either need to switch to using CHECK-DAG, or ideally teach
+// the diagnostic verifier about macro expansion buffers.
+func invalidDeclarationMacro2() {
+  struct LocalThing1 {
+    func f() {
+      #accidentalCodeItem
+      // expected-note@-1 {{in expansion of macro 'accidentalCodeItem' here}}
+      /*
+      expected-expansion@-3:7 {{
+        expected-error@1:1{{expected macro expansion to produce a declaration}}
+      }}
+      */
+    }
+  }
+}
 #endif
+
+// Make sure we compute captures for the introduced stored property here.
+struct HasStoredProperty {
+  #AddStoredProperty(0)
+}
+class HasStoredPropertyClass {
+  #AddStoredProperty(0)
+}
diff --git a/test/Macros/macro_expand_body.swift b/test/Macros/macro_expand_body.swift
index ebd86736c3646..1cb9a4c72f836 100644
--- a/test/Macros/macro_expand_body.swift
+++ b/test/Macros/macro_expand_body.swift
@@ -1,4 +1,4 @@
-// REQUIRES: swift_swift_parser, executable_test, asserts, concurrency
+// REQUIRES: swift_swift_parser, executable_test, asserts, concurrency, concurrency_runtime
 // REQUIRES: swift_feature_PreambleMacros
 // RUN: %empty-directory(%t)
 // RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift -g -no-toolchain-stdlib-rpath -swift-version 5
@@ -46,7 +46,6 @@ func log(_ message: String) {
   print(message)
 }
 
-@available(SwiftStdlib 5.1, *)
 func remoteCall<Result: ConjureRemoteValue>(function: String, arguments: [String: Any]) async throws -> Result {
   let printedArgs = arguments.keys.sorted().map { key in
     "\(key): \(arguments[key]!)"
@@ -55,7 +54,6 @@ func remoteCall<Result: ConjureRemoteValue>(function: String, arguments: [String
   return Result.conjureValue()
 }
 
-@available(SwiftStdlib 5.1, *)
 @Remote
 func f(a: Int, b: String) async throws -> String
 
@@ -71,7 +69,6 @@ func useLogger() {
   print(x)
 }
 
-@available(SwiftStdlib 5.1, *)
 @Remote
 @Traced
 @Logged
@@ -80,7 +77,6 @@ func g(a: Int, b: String) async throws -> String {
 }
 
 #if compiler(>=6.0) && TEST_DIAGNOSTICS
-@available(SwiftStdlib 5.1, *)
 @Remote
 func h(a: Int, b: String) async throws -> String {
   does not
@@ -93,17 +89,15 @@ func h(a: Int, b: String) async throws -> String {
 // CHECK-NEXT: Exiting doubleTheValue(value:)
 _ = doubleTheValue(value: 7)
 
-if #available(SwiftStdlib 5.1, *) {
-  // CHECK: Remote call f(a: 5, b: Hello)
-  print(try await f(a: 5, b: "Hello"))
+// CHECK: Remote call f(a: 5, b: Hello)
+print(try await f(a: 5, b: "Hello"))
 
-  // CHECK: Entering g(a: 5, b: World)
-  // CHECK: Logger entering g(a: 5, b: World)
-  // CHECK: Remote call g(a: 5, b: World)
-  // CHECK: Logger exiting g(a:b:)
-  // CHECK: Exiting g(a:b:)
-  print(try await g(a: 5, b: "World"))
-}
+// CHECK: Entering g(a: 5, b: World)
+// CHECK: Logger entering g(a: 5, b: World)
+// CHECK: Remote call g(a: 5, b: World)
+// CHECK: Logger exiting g(a:b:)
+// CHECK: Exiting g(a:b:)
+print(try await g(a: 5, b: "World"))
 
 // CHECK: Logger entering useLogger()
 // CHECK: --- use it
diff --git a/test/Macros/macro_expand_extensions.swift b/test/Macros/macro_expand_extensions.swift
index 4a70143e7d344..0ee4e20d0e1d9 100644
--- a/test/Macros/macro_expand_extensions.swift
+++ b/test/Macros/macro_expand_extensions.swift
@@ -10,9 +10,6 @@
 // RUN: %FileCheck -check-prefix=CHECK-DUMP %s < %t/expansions-dump.txt
 // RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser -DTEST_DIAGNOSTICS -swift-version 5 -I %t
 
-// RUN: not %target-swift-frontend -swift-version 5 -typecheck -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser -DTEST_DIAGNOSTICS -serialize-diagnostics-path %t/macro_expand.dia %s -emit-macro-expansion-files no-diagnostics
-// RUN: c-index-test -read-diagnostics %t/macro_expand.dia 2>&1 | %FileCheck -check-prefix CHECK-DIAGS %s
-
 // Ensure that we can serialize this file as a module.
 // RUN: %target-swift-frontend -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) %s -I %t -disable-availability-checking -emit-module -o %t/MyModule.swiftmodule -enable-testing
 
@@ -137,8 +134,11 @@ macro UndocumentedNamesInExtension() = #externalMacro(module: "MacroDefinition",
 @UndocumentedNamesInExtension
 struct S<Element> {}
 // expected-note@-2 {{in expansion of macro 'UndocumentedNamesInExtension' on generic struct 'S' here}}
-
-// CHECK-DIAGS: error: declaration name 'requirement()' is not covered by macro 'UndocumentedNamesInExtension'
+/*
+expected-expansion@-3:21 {{
+  expected-error@2:15{{declaration name 'requirement()' is not covered by macro 'UndocumentedNamesInExtension'}}
+}}
+*/
 
 @attached(extension, names: named(requirement))
 macro UndocumentedConformanceInExtension() = #externalMacro(module: "MacroDefinition", type: "AlwaysAddConformance")
@@ -146,8 +146,11 @@ macro UndocumentedConformanceInExtension() = #externalMacro(module: "MacroDefini
 @UndocumentedConformanceInExtension
 struct InvalidConformance<Element> {}
 // expected-note@-2 {{in expansion of macro 'UndocumentedConformanceInExtension' on generic struct 'InvalidConformance' here}}
-
-// CHECK-DIAGS: error: conformance to 'P' is not covered by macro 'UndocumentedConformanceInExtension'
+/*
+expected-expansion@-3:38 {{
+  expected-error@1:1{{conformance to 'P' is not covered by macro 'UndocumentedConformanceInExtension'}}
+}}
+*/
 
 @attached(extension)
 macro UndocumentedCodable() = #externalMacro(module: "MacroDefinition", type: "AlwaysAddCodable")
@@ -155,8 +158,11 @@ macro UndocumentedCodable() = #externalMacro(module: "MacroDefinition", type: "A
 @UndocumentedCodable
 struct TestUndocumentedCodable {}
 // expected-note@-2 {{in expansion of macro 'UndocumentedCodable' on struct 'TestUndocumentedCodable' here}}
-
-// CHECK-DIAGS: error: conformance to 'Codable' (aka 'Decodable & Encodable') is not covered by macro 'UndocumentedCodable'
+/*
+expected-expansion@-3:34 {{
+  expected-error@1:1{{conformance to 'Codable' (aka 'Decodable & Encodable') is not covered by macro 'UndocumentedCodable'}}
+}}
+*/
 
 @attached(extension, conformances: Decodable)
 macro UndocumentedEncodable() = #externalMacro(module: "MacroDefinition", type: "AlwaysAddCodable")
@@ -164,8 +170,11 @@ macro UndocumentedEncodable() = #externalMacro(module: "MacroDefinition", type:
 @UndocumentedEncodable
 struct TestUndocumentedEncodable {}
 // expected-note@-2 {{in expansion of macro 'UndocumentedEncodable' on struct 'TestUndocumentedEncodable' here}}
-
-// CHECK-DIAGS: error: conformance to 'Codable' (aka 'Decodable & Encodable') is not covered by macro 'UndocumentedEncodable'
+/*
+expected-expansion@-3:36 {{
+  expected-error@1:1{{conformance to 'Codable' (aka 'Decodable & Encodable') is not covered by macro 'UndocumentedEncodable'}}
+}}
+*/
 
 @attached(extension)
 macro BadExtension() = #externalMacro(module: "MacroDefinition", type: "BadExtensionMacro")
@@ -176,7 +185,11 @@ struct HasSomeNestedType {
   @BadExtension // expected-note {{in expansion of macro 'BadExtension' on struct 'SomeNestedType' here}}
   struct SomeNestedType {}
 }
-// CHECK-DIAGS: error: cannot find type 'SomeNestedType' in scope
+/*
+expected-expansion@-2:2 {{
+  expected-error@1:11{{cannot find type 'SomeNestedType' in scope}}
+}}
+*/
 
 #endif
 
@@ -269,7 +282,7 @@ macro AddSendable() = #externalMacro(module: "MacroDefinition", type: "SendableM
 final class SendableClass {
 }
 
-// expected-warning@+2 {{non-final class 'InvalidSendableClass' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+// expected-warning@+2 {{non-final class 'InvalidSendableClass' cannot conform to the 'Sendable' protocol}}
 @AddSendable
 class InvalidSendableClass {
 }
@@ -283,3 +296,15 @@ struct HasNestedType {
 // extensions of nested types when the outer type has an
 // attached macro that can add other nested types.
 extension HasNestedType.Inner {}
+
+@attached(extension, conformances: P, names: named(requirement))
+macro AddPWithNonisolated() = #externalMacro(module: "MacroDefinition", type: "PWithNonisolatedFuncMacro")
+
+@attached(extension, conformances: P, names: named(requirement))
+macro AddNonisolatedPWithNonisolated() = #externalMacro(module: "MacroDefinition", type: "NonisolatedPWithNonisolatedFuncMacro")
+
+@AddNonisolatedPWithNonisolated
+struct MakeMeNonisolated { }
+
+@AddPWithNonisolated
+struct KeepMeIsolated { }
diff --git a/test/Macros/macro_expand_other.swift b/test/Macros/macro_expand_other.swift
index 4d210deb76d8c..b215e1d2effe3 100644
--- a/test/Macros/macro_expand_other.swift
+++ b/test/Macros/macro_expand_other.swift
@@ -32,7 +32,15 @@ func testFreestandingExpansionOfOther() {
 
   #if TEST_DIAGNOSTICS
 #recurseThrough(true)
-  // expected-note@-1 {{in expansion of macro 'recurseThrough' here}}
+  /*
+     expected-expansion@-2:1{{
+       expected-expansion@1:1{{
+         expected-error@1:1{{recursive expansion of macro 'recurse'}}
+       }}
+       expected-note@1:1{{in expansion of macro 'recurse' here}}
+     }}
+     expected-note@-8 {{in expansion of macro 'recurseThrough' here}}
+  */
   #endif
 }
 
diff --git a/test/Macros/macro_expand_peers.swift b/test/Macros/macro_expand_peers.swift
index 99f8febe7fe7f..6e90bf8061f67 100644
--- a/test/Macros/macro_expand_peers.swift
+++ b/test/Macros/macro_expand_peers.swift
@@ -309,3 +309,37 @@ func closuresInPeerMacroCrash() {}
 @trait(Trait {})
 @trait(Trait {})
 var closuresInPeerMacroOnVariableCrash: Int = 0
+
+// Test that macros can't be used in @abi
+
+#if swift(>=5.3) && TEST_DIAGNOSTICS
+struct ABIAttrWithAttachedMacro {
+  // expected-error@+1 {{macro 'addCompletionHandler()' cannot be expanded in '@abi' attribute}}
+  @abi(@addCompletionHandler func fn1() async)
+  @addCompletionHandler func fn1() async {}
+  /*
+    expected-expansion@-2:44{{
+      expected-error@2:8{{macro 'addCompletionHandler()' cannot be expanded in '@abi' attribute}}
+      expected-error@2:35{{invalid redeclaration of 'fn1()'}}
+      expected-error@4:23{{argument passed to call that takes no arguments}}
+    }}
+    expected-note@-7 3{{in expansion of macro 'addCompletionHandler' on instance method 'fn1()' here}}
+    expected-note@-9 {{'fn1()' previously declared here}}
+  */
+
+  // expected-error@+1 {{macro 'addCompletionHandler()' cannot be expanded in '@abi' attribute}}
+  @abi(@addCompletionHandler func fn2() async)
+  func fn2() async {}
+
+  @abi(func fn3() async)
+  @addCompletionHandler func fn3() async {}
+  /*
+    expected-expansion@-2:44{{
+      expected-error@1:11{{invalid redeclaration of 'fn3()'}}
+      expected-error@3:23{{argument passed to call that takes no arguments}}
+    }}
+    expected-note@-6 2{{in expansion of macro 'addCompletionHandler' on instance method 'fn3()' here}}
+    expected-note@-8 {{'fn3()' previously declared here}}
+  */
+}
+#endif
diff --git a/test/Macros/macro_expand_synthesized_members.swift b/test/Macros/macro_expand_synthesized_members.swift
index 5001f1ab9b689..08443d83bad87 100644
--- a/test/Macros/macro_expand_synthesized_members.swift
+++ b/test/Macros/macro_expand_synthesized_members.swift
@@ -105,12 +105,17 @@ print(ElementType.paper.unknown())
 #if TEST_DIAGNOSTICS
 @addMembersQuotedInit
 struct S2 {
-// expected-note@-2 {{in expansion of macro 'addMembersQuotedInit' on struct 'S2' here}}
   func useSynthesized() {
     S.method()
     print(type(of: getStorage()))
   }
 }
+/*
+expected-expansion@-2:1{{
+  expected-error@14:1{{declaration name 'init()' is not covered by macro 'addMembersQuotedInit'}}
+}}
+expected-note@-11 {{in expansion of macro 'addMembersQuotedInit' on struct 'S2' here}}
+*/
 #endif
 
 @attached(
diff --git a/test/Macros/macro_explicit_generic_args.swift b/test/Macros/macro_explicit_generic_args.swift
index c49e88a84cb25..9da2ea5e6d9cc 100644
--- a/test/Macros/macro_explicit_generic_args.swift
+++ b/test/Macros/macro_explicit_generic_args.swift
@@ -22,3 +22,16 @@ func test(i: Int) {
   // expected-error@-1{{external macro implementation type 'A.B' could not be found for macro 'resolve'; plugin for module 'A' not found}}
 }
 
+@freestanding(expression)
+macro OverloadedMacro<T, U>(_ x: T, _ y: U) // expected-error {{requires a definition}} expected-note {{declared here}}
+
+@freestanding(expression)
+macro OverloadedMacro<T, U>(_ x: T, _ y: U, z: Int = 0) // expected-error {{requires a definition}}
+
+// Make sure we don't crash.
+func testOverloadedMacro() {
+  struct S<T> {} // expected-note 2{{'T' declared as parameter to type 'S'}}
+  _ = #OverloadedMacro<S, S>
+  // expected-error@-1 2{{generic parameter 'T' could not be inferred}}
+  // expected-error@-2 {{missing arguments for parameters #1, #2 in macro expansion}}
+}
diff --git a/test/Macros/macro_fixits.swift b/test/Macros/macro_fixits.swift
index 66d5f6de82552..13d27e26b6e22 100644
--- a/test/Macros/macro_fixits.swift
+++ b/test/Macros/macro_fixits.swift
@@ -7,12 +7,7 @@
 
 // RUN: %host-build-swift -emit-library %S/Inputs/syntax_macro_definitions.swift -o %t/%target-library-name(MacroDefinition) -module-name MacroDefinition -swift-version 5 -g -no-toolchain-stdlib-rpath
 
-// RUN: %target-swift-frontend -typecheck %s -load-plugin-library %t/%target-library-name(MacroDefinition) -swift-version 5 -serialize-diagnostics-path %t/diags.dia -fixit-all -emit-fixits-path %t/fixits.json
-
-// RUN: %FileCheck %s --check-prefix FIXITS-JSON < %t/fixits.json
-
-// FIXITS-JSON:      [
-// FIXITS-JSON-NEXT: ]
+// RUN: %target-swift-frontend -typecheck %s -load-plugin-library %t/%target-library-name(MacroDefinition) -swift-version 5 -serialize-diagnostics-path %t/diags.dia
 
 // RUN: c-index-test -read-diagnostics %t/diags.dia 2>&1 | %FileCheck -check-prefix DIAGS %s
 
diff --git a/test/Macros/macro_misc_diags.swift b/test/Macros/macro_misc_diags.swift
index 3bd8fd8035b4b..4201c04639621 100644
--- a/test/Macros/macro_misc_diags.swift
+++ b/test/Macros/macro_misc_diags.swift
@@ -36,6 +36,32 @@ public struct TrailingClosureMacro: ExpressionMacro {
   }
 }
 
+public struct CallClosureMacro: ExpressionMacro {
+  public static func expansion(
+    of macro: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) -> ExprSyntax {
+    guard let argument = macro.trailingClosure else {
+      fatalError()
+    }
+    return "\(argument)()"
+  }
+}
+
+public struct AddFunctionThatCallsClosureMacro: PeerMacro {
+  public static func expansion(
+    of node: AttributeSyntax,
+    providingPeersOf declaration: some DeclSyntaxProtocol,
+    in context: some MacroExpansionContext
+  ) throws -> [DeclSyntax] {
+    guard case .argumentList(let args) = node.arguments else {
+      fatalError()
+    }
+    let arg = args.first!
+    return ["func qux() { \(arg)() }"]
+  }
+}
+
 public struct MakeBinding : DeclarationMacro {
   static public func expansion(
     of node: some FreestandingMacroExpansionSyntax,
@@ -64,6 +90,12 @@ macro identity<T>(_ x: T) -> T = #externalMacro(module: "MacroPlugin", type: "Id
 @freestanding(expression)
 macro trailingClosure<T>(_ x: T) -> T = #externalMacro(module: "MacroPlugin", type: "TrailingClosureMacro")
 
+@freestanding(expression)
+macro takesNonEscapingClosure(_ x: () -> Void) = #externalMacro(module: "MacroPlugin", type: "CallClosureMacro")
+
+@attached(peer, names: named(qux))
+macro AddFunctionThatCallsClosure<T>(_ fn: () -> T) = #externalMacro(module: "MacroPlugin", type: "AddFunctionThatCallsClosureMacro")
+
 @freestanding(declaration, names: named(x))
 macro makeBinding<T>(_ x: T) = #externalMacro(module: "MacroPlugin", type: "MakeBinding")
 
@@ -160,3 +192,29 @@ class rdar138997009_Class {
     }
   }
 }
+
+// https://github.com/swiftlang/swift/issues/80561
+class TestNonEscaping {
+  func foo() {}
+  func bar() {
+    _ = #takesNonEscapingClosure {
+      foo()
+    }
+    _ = {
+      _ = #takesNonEscapingClosure {
+        foo()
+        // CHECK-DIAG: @__swiftmacro_6Client0017Clientswift_yEEFcfMX[[@LINE-3]]{{.*}}takesNonEscapingClosurefMf_.swift:2:9: error: call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit
+        // CHECK-DIAG: Client.swift:[[@LINE-2]]:9: warning: call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit; this will be an error in a future Swift language mode
+      }
+    }
+
+    @AddFunctionThatCallsClosure({ foo() })
+    func baz() {}
+  }
+  func qux() {
+    @AddFunctionThatCallsClosure({ _ = { foo() } })
+    func baz() {}
+    // CHECK-DIAG: Client.swift:[[@LINE-2]]:42: warning: call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit; this will be an error in a future Swift language mode
+    // CHECK-DIAG: @__swiftmacro_6Client15TestNonEscapingC3quxyyF7baz_$l{{.*}}AddFunctionThatCallsClosurefMp_.swift:4:13: error: call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit
+  }
+}
diff --git a/test/Macros/macro_plugin_basic.swift b/test/Macros/macro_plugin_basic.swift
index 3208b0e73fed9..b85c90a7e89c8 100644
--- a/test/Macros/macro_plugin_basic.swift
+++ b/test/Macros/macro_plugin_basic.swift
@@ -30,9 +30,9 @@
 
 // CHECK: ->(plugin:[[#PID:]]) {"getCapability":{"capability":{"protocolVersion":[[#PROTOCOL_VERSION:]]}}}
 // CHECK: <-(plugin:[[#PID]]) {"getCapabilityResult":{"capability":{"protocolVersion":1}}}
-// CHECK: ->(plugin:[[#PID]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}func test{{.*}}],"macro":{"moduleName":"TestPlugin","name":"testString","typeName":"TestStringMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":5,"offset":301},"source":"#testString(123)"}}}
+// CHECK: ->(plugin:[[#PID]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}func test{{.*}}],"macro":{"moduleName":"TestPlugin","name":"testString","typeName":"TestStringMacro"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":5,"offset":301},"source":"#testString(123)"}}}
 // CHECK: <-(plugin:[[#PID]]) {"expandFreestandingMacroResult":{"diagnostics":[],"expandedSource":"\"123\"\n  +   \"foo  \""}}
-// CHECK: ->(plugin:[[#PID]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"testStringWithError","typeName":"TestStringWithErrorMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":6,"offset":336},"source":"#testStringWithError(321)"}}}
+// CHECK: ->(plugin:[[#PID]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"testStringWithError","typeName":"TestStringWithErrorMacro"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":6,"offset":336},"source":"#testStringWithError(321)"}}}
 // CHECK: <-(plugin:[[#PID]]) {"expandFreestandingMacroResult":{"diagnostics":[{"fixIts":[],"highlights":[],"message":"message from plugin","notes":[],"position":{"fileName":"{{.*}}test.swift","offset":336},"severity":"error"}],"expandedSource":"\"bar\""}}
 
 //--- test.swift
diff --git a/test/Macros/macro_plugin_error.swift b/test/Macros/macro_plugin_error.swift
index a4d6bd3865df3..becbcda13afcc 100644
--- a/test/Macros/macro_plugin_error.swift
+++ b/test/Macros/macro_plugin_error.swift
@@ -18,14 +18,14 @@
 
 // CHECK: ->(plugin:[[#PID1:]]) {"getCapability":{"capability":{"protocolVersion":[[#PROTOCOL_VERSION:]]}}}
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"getCapabilityResult":{"capability":{"protocolVersion":1}}}
-// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":7,"offset":[[#]]},"source":"#fooMacro(1)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":7,"offset":[[#]]},"source":"#fooMacro(1)"}}}
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"invalidResponse":{}}
-// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":9,"offset":[[#]]},"source":"#fooMacro(2)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":9,"offset":[[#]]},"source":"#fooMacro(2)"}}}
 // ^ This messages causes the mock plugin exit because there's no matching expected message.
 
 // CHECK: ->(plugin:[[#PID2:]]) {"getCapability":{"capability":{"protocolVersion":[[#PROTOCOL_VERSION]]}}}
 // CHECK-NEXT: <-(plugin:[[#PID2]]) {"getCapabilityResult":{"capability":{"protocolVersion":1}}}
-// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":11,"offset":[[#]]},"source":"#fooMacro(3)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":11,"offset":[[#]]},"source":"#fooMacro(3)"}}}
 // CHECK-NEXT: <-(plugin:[[#PID2:]]) {"expandFreestandingMacroResult":{"diagnostics":[],"expandedSource":"3.description"}}
 
 //--- test.swift
diff --git a/test/Macros/macro_plugin_server.swift b/test/Macros/macro_plugin_server.swift
index c222f7dada18a..fa9e20574aec6 100644
--- a/test/Macros/macro_plugin_server.swift
+++ b/test/Macros/macro_plugin_server.swift
@@ -71,9 +71,9 @@
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"loadPluginLibraryResult":{"diagnostics":[],"loaded":true}}
 // CHECK-NEXT: ->(plugin:[[#PID1]]) {"loadPluginLibrary":{"libraryPath":"{{.*}}EvilMacros.{{dylib|so|dll}}","moduleName":"EvilMacros"}}
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"loadPluginLibraryResult":{"diagnostics":[],"loaded":true}}
-// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"stringify","typeName":"StringifyMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{.+}}},"source":"#stringify(a + b)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"stringify","typeName":"StringifyMacro"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{{{.+}}},"source":"#stringify(a + b)"}}}
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"expandMacroResult":{"diagnostics":[],"expandedSource":"(a + b, \"a + b\")"}}
-// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"EvilMacros","name":"evil","typeName":"CrashingMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{.+}}},"source":"#evil(42)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"EvilMacros","name":"evil","typeName":"CrashingMacro"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{{{.+}}},"source":"#evil(42)"}}}
 // ^ This crashes the plugin server.
 
 // CHECK: ->(plugin:[[#PID2:]]) {"getCapability":{"capability":{"protocolVersion":[[#PROTOCOL_VERSION]]}}}
@@ -82,13 +82,13 @@
 // CHECK-NEXT: <-(plugin:[[#PID2]]) {"loadPluginLibraryResult":{"diagnostics":[],"loaded":true}}
 // CHECK-NEXT: ->(plugin:[[#PID2]]) {"loadPluginLibrary":{"libraryPath":"{{.*}}EvilMacros.{{dylib|so|dll}}","moduleName":"EvilMacros"}}
 // CHECK-NEXT: <-(plugin:[[#PID2]]) {"loadPluginLibraryResult":{"diagnostics":[],"loaded":true}}
-// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"stringify","typeName":"StringifyMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{.+}}},"source":"#stringify(b + a)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"stringify","typeName":"StringifyMacro"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{{{.+}}},"source":"#stringify(b + a)"}}}
 // CHECK-NEXT: <-(plugin:[[#PID2]]) {"expandMacroResult":{"diagnostics":[],"expandedSource":"(b + a, \"b + a\")"}}
 
-// CHECK-NEXT ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"missing","typeName":"TypeDoesNotExist"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{*}}},"source":" #missing()"}}}
-// CHECK-NEXT <-(plugin:[[#PID2]]) {"expandMacroResult":{"diagnostics":[{"fixIts":[],"highlights":[{{{.*}}}],"message":"macro implementation type 'MacroDefinition.TypeDoesNotExist' could not be found in library plugin '{{.*}}MacroDefinition.{{dylib|so|dll}}'","notes":[],"position":{{{.*}}},"severity":"error"}]}}
-// CHECK-NEXT ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"missing","typeName":"TypeDoesNotExist"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{*}}},"source":" #notMacro()"}}}
-// CHECK-NEXT <-(plugin:[[#PID2]]) {"expandMacroResult":{"diagnostics":[{"fixIts":[],"highlights":[{{{.*}}}],"message":"type 'MacroDefinition.NotMacroStruct' is not a valid macro implementation type in library plugin '{{.*}}MacroDefinition.{{dylib|so|dll}}'","notes":[],"position":{{{.*}}},"severity":"error"}]}}
+// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"missing","typeName":"TypeDoesNotExist"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{{({.+})}},"source":"#missing()"}}}
+// CHECK-NEXT: <-(plugin:[[#PID2]]) {"expandMacroResult":{"diagnostics":[{"fixIts":[],"highlights":[{{{.*}}}],"message":"type 'MacroDefinition.TypeDoesNotExist' could not be found in library plugin '{{.*}}MacroDefinition.{{dylib|so|dll}}'","notes":[],"position":{{{.*}}},"severity":"error"}]}}
+// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"notMacro","typeName":"NotMacroStruct"},"macroRole":"expression","staticBuildConfiguration"{{.*}},"syntax":{"kind":"expression","location":{{({.+})}},"source":"#notMacro()"}}}
+// CHECK-NEXT: <-(plugin:[[#PID2]]) {"expandMacroResult":{"diagnostics":[{"fixIts":[],"highlights":[{{{.*}}}],"message":"type 'MacroDefinition.NotMacroStruct' is not a valid macro implementation type in library plugin '{{.*}}MacroDefinition.{{dylib|so|dll}}'","notes":[],"position":{{{.*}}},"severity":"error"}]}}
 
 @freestanding(expression) macro stringify<T>(_ value: T) -> (T, String) = #externalMacro(module: "MacroDefinition", type: "StringifyMacro")
 @freestanding(expression) macro evil(_ value: Int) -> String = #externalMacro(module: "EvilMacros", type: "CrashingMacro")
diff --git a/test/Macros/macro_plugin_server_mod.swift b/test/Macros/macro_plugin_server_mod.swift
index 8755f5440f215..c1726977b4d8d 100644
--- a/test/Macros/macro_plugin_server_mod.swift
+++ b/test/Macros/macro_plugin_server_mod.swift
@@ -36,7 +36,7 @@
 // RUN:   -external-plugin-path %t/plugins#%swift-plugin-server
 
 // RUN: env SWIFT_DUMP_PLUGIN_MESSAGING=1 %target-swift-frontend \
-// RUN:   -typecheck -verify \
+// RUN:   -typecheck -verify -verify-ignore-unrelated \
 // RUN:   -I %t \
 // RUN:   -swift-version 5 \
 // RUN:   -external-plugin-path %t/plugins#%swift-plugin-server \
diff --git a/test/Macros/macro_self.swift b/test/Macros/macro_self.swift
index 47b278568314c..e866740304161 100644
--- a/test/Macros/macro_self.swift
+++ b/test/Macros/macro_self.swift
@@ -1,12 +1,14 @@
 // RUN: %target-swift-frontend -parse %s -verify
 
-@freestanding(expression) // expected-error {{expected expression}}
+@freestanding(expression)
 macro self() = #externalMacro(module: "MacroDefinition", type: "InvalidMacro")
+// expected-error@-1 {{expected declaration}}
 
 func sync() {}
 
-@freestanding(expression) // expected-error {{expected expression}}
+@freestanding(expression)
 macro Self() = #externalMacro(module: "MacroDefinition", type: "InvalidMacro")
+// expected-error@-1 {{expected declaration}}
 
 func testSelfAsFreestandingMacro() {
   _ = #self
diff --git a/test/Macros/macros_diagnostics.swift b/test/Macros/macros_diagnostics.swift
index 40a0b3a1c89af..60af15973b76c 100644
--- a/test/Macros/macros_diagnostics.swift
+++ b/test/Macros/macros_diagnostics.swift
@@ -6,7 +6,7 @@
 @expression macro stringify<T>(_ value: T) -> (T, String) = #externalMacro(module: "MacroDefinition", type: "StringifyMacro")
 // expected-note@-1 3{{'stringify' declared here}}
 // expected-warning@-2{{external macro implementation type}}
-// expected-warning@-3{{@expression has been removed in favor of @freestanding(expression)}}{{1-12=@freestanding(expression)}}
+// expected-warning@-3{{'@expression' has been removed in favor of '@freestanding(expression)'}}{{1-12=@freestanding(expression)}}
 @freestanding(expression) macro missingMacro1(_: Any) = MissingModule.MissingType // expected-note{{'missingMacro1' declared here}}
 // expected-warning@-1{{external macro definitions are now written using #externalMacro}}
 // expected-warning@-2{{external macro implementation type}}
@@ -234,3 +234,10 @@ func someGlobalNext(
 ) async throws {
   fatalError()
 }
+
+// This is testing if the definition is actually checked. The error means the '#externalMacro' was correctly parsed and checked.
+#if true
+@available(*, unavailable)
+#endif
+@freestanding(expression) public macro MacroWithIfConfigAttr() = #externalMacro(module: "ThisMacroModuleDoesNotExist", type: "ThisMacroTypeDoesNotExist")
+// expected-warning@-1{{external macro implementation type 'ThisMacroModuleDoesNotExist.ThisMacroTypeDoesNotExist'}}
diff --git a/test/Macros/parsing.swift b/test/Macros/parsing.swift
index ffc039386d8d7..67c23ca6feb54 100644
--- a/test/Macros/parsing.swift
+++ b/test/Macros/parsing.swift
@@ -46,7 +46,7 @@ macro am1()
 
 @attached(
   accessor,
-  overloaded, // expected-error{{@attached argument is missing label 'names'}}
+  overloaded, // expected-error{{'@attached' argument is missing label 'names'}}
   unknown, // expected-error{{unknown introduced name kind 'unknown'}}
   named, // expected-error{{introduced name kind 'named' requires a single argument '(name)'}}
   arbitrary(a) // expected-error{{introduced name kind 'arbitrary' must not have an argument}}
diff --git a/test/Macros/print_clang_expand_on_imported.swift b/test/Macros/print_clang_expand_on_imported.swift
index 869eefb9c8ea1..6003ebf0df3c1 100644
--- a/test/Macros/print_clang_expand_on_imported.swift
+++ b/test/Macros/print_clang_expand_on_imported.swift
@@ -1,4 +1,4 @@
-// REQUIRES: swift_swift_parser, executable_test, concurrency
+// REQUIRES: swift_swift_parser, concurrency, string_processing
 // REQUIRES: swift_feature_MacrosOnImports
 
 // RUN: %empty-directory(%t)
diff --git a/test/Macros/print_clang_expand_on_imported_objc.swift b/test/Macros/print_clang_expand_on_imported_objc.swift
index bb49bd756841c..484a7a80a4069 100644
--- a/test/Macros/print_clang_expand_on_imported_objc.swift
+++ b/test/Macros/print_clang_expand_on_imported_objc.swift
@@ -1,4 +1,4 @@
-// REQUIRES: swift_swift_parser, executable_test, objc_interop, concurrency
+// REQUIRES: swift_swift_parser, objc_interop, concurrency, string_processing
 // REQUIRES: swift_feature_MacrosOnImports
 
 // RUN: %empty-directory(%t)
diff --git a/test/Macros/rdar154771596.swift b/test/Macros/rdar154771596.swift
new file mode 100644
index 0000000000000..6a0ef657cd52d
--- /dev/null
+++ b/test/Macros/rdar154771596.swift
@@ -0,0 +1,28 @@
+// REQUIRES: swift_swift_parser
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift -g -no-toolchain-stdlib-rpath
+
+// RUN: %target-swift-frontend -emit-module %t/Lib.swift -module-name Lib -emit-module-path %t/Lib.swiftmodule
+
+// RUN: %target-swift-frontend -typecheck -verify -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -I %t %t/a.swift -primary-file %t/b.swift
+
+//--- Lib.swift
+
+@freestanding(expression)
+public macro magicFile() -> String = #externalMacro(module: "MacroDefinition", type: "MagicFileMacro")
+
+//--- a.swift
+
+import Lib
+
+func foo(x: String = #magicFile) {}
+
+//--- b.swift
+
+// We're missing the necessary import in this file, make sure we diagnose.
+func bar() {
+  foo() // expected-error {{no macro named 'magicFile'}}
+}
diff --git a/test/Macros/task_macro.swift b/test/Macros/task_macro.swift
deleted file mode 100644
index b13d4091a0229..0000000000000
--- a/test/Macros/task_macro.swift
+++ /dev/null
@@ -1,157 +0,0 @@
-// REQUIRES: swift_swift_parser, swift_feature_ConcurrencySyntaxSugar, swift_feature_ClosureBodyMacro
-
-// RUN: %target-swift-frontend -typecheck -plugin-path %swift-plugin-dir -enable-experimental-feature ConcurrencySyntaxSugar -enable-experimental-feature ClosureBodyMacro -language-mode 6 %s -dump-macro-expansions -disable-availability-checking 2>&1 | %FileCheck %s
-
-func f() async {}
-
-// CHECK-LABEL: @__swiftmacro_10task_macro4sync4TaskfMb_.swift
-// CHECK: Task {
-// CHECK:   await f()
-// CHECK: }
-
-@Task
-func sync() {
-  await f()
-}
-
-func takeClosure(
-  _ closure: @escaping @Sendable () -> Void,
-  v: Int = 42
-) {
-  closure()
-}
-
-func multipleClosures(
-  a: @escaping @Sendable () -> Void,
-  b: @escaping @Sendable () -> Void) {
-}
-
-func onClosure() {
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX35_16_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task {
-  // CHECK:         await f()
-  // CHECK:     }
-  // CHECK: }
-  takeClosure { @Task in
-    await f()
-  }
-
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX45_16_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task {
-  // CHECK:         await f()
-  // CHECK:     }
-  // CHECK: }
-  takeClosure({ @Task in
-    await f()
-  }, v: 0)
-
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX55_21_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task {
-  // CHECK:         await f()
-  // CHECK:     }
-  // CHECK: }
-  multipleClosures { @Task in
-    await f()
-  } b: {
-  }
-
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX68_9_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task {
-  // CHECK:         await f()
-  // CHECK:     }
-  // CHECK: }
-  multipleClosures {
-    _ = 42
-  } b: { @Task in
-    await f()
-  }
-
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX86_4_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task {
-  // CHECK:         _ = 42
-  // CHECK:     }
-  // CHECK: }
-  
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX88_9_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task {
-  // CHECK:         await f()
-  // CHECK:     }
-  // CHECK: }
-  multipleClosures {
-    @Task in
-    _ = 42
-  } b: { @Task in
-    await f()
-  }
-
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX100_12_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task {
-  // CHECK:         await f()
-  // CHECK:     }
-  // CHECK: }
-  let _ = {
-    func test() {
-      _ = { @Task in await f() }
-    }
-  }
-
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX114_54_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task {
-  // CHECK:         await test()
-  // CHECK:     }
-  // CHECK: }
-  let _ = {
-    let y = 42
-    func test() async { print(y) }
-    
-    if case let (_, closure) = (otherValue: 42, fn: { @Task in
-         await test()
-      }) {
-      let _: Task<(), Never> = closure()
-    }
-  }
-}
-
-func onClosureWithArguments() {
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX129_16_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task { @MainActor in
-  // CHECK:         await f()
-  // CHECK:     }
-  // CHECK: }
-  takeClosure { @Task(on: MainActor.shared) in
-    await f()
-  }
-
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX139_16_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task(name: "MyTask") { @MainActor in
-  // CHECK:         await f()
-  // CHECK:     }
-  // CHECK: }
-  takeClosure { @Task(on: MainActor.shared, name: "MyTask") in
-    await f()
-  }
-
-  // CHECK-LABEL: @__swiftmacro_10task_macro0021task_macroswift_IfFDefMX149_16_33_39E2B7F186C0B70273105736DD2F3721Ll4TaskfMb_.swift
-  // CHECK: {
-  // CHECK:     Task(name: "MyTask", priority: .high) {
-  // CHECK:         await f()
-  // CHECK:     }
-  // CHECK: }
-  takeClosure { @Task(name: "MyTask", priority: .high) in
-    await f()
-  }
-}
-
-// FIXME: Remove `-disable-availability-checking` from the run line after
-// SE-0469 review wraps up. This comment is at the end of the file because
-// closure body macro mangling includes source locations.
diff --git a/test/Macros/top_level_freestanding.swift b/test/Macros/top_level_freestanding.swift
index d5ffcee95931a..4be717f1c6a08 100644
--- a/test/Macros/top_level_freestanding.swift
+++ b/test/Macros/top_level_freestanding.swift
@@ -12,10 +12,6 @@
 
 // RUN: %target-typecheck-verify-swift -swift-version 5 -parse-as-library -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser -DTEST_DIAGNOSTICS -DIMPORT_MACRO_LIBRARY -swift-version 5  %S/Inputs/top_level_freestanding_other.swift -I %t
 
-// Check diagnostic buffer names
-// RUN: not %target-swift-frontend -typecheck -swift-version 5 -parse-as-library -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser -DTEST_DIAGNOSTICS -swift-version 5 %s %S/Inputs/top_level_freestanding_other.swift -diagnostic-style llvm 2> %t.diags
-// RUN: %FileCheck -check-prefix DIAG_BUFFERS %s < %t.diags
-
 // Execution testing
 // RUN: %target-build-swift -g -swift-version 5 -parse-as-library -load-plugin-library %t/%target-library-name(MacroDefinition) %s %S/Inputs/top_level_freestanding_other.swift -o %t/main -module-name MacroUser -swift-version 5
 // RUN: %target-codesign %t/main
@@ -60,7 +56,7 @@ func lookupGlobalFreestandingExpansion() {
 
 #anonymousTypes(public: true) { "hello" }
 
-// CHECK-SIL: sil @$s9MacroUser03$s9A115User0033top_level_freestandingswift_DbGHjfMX60_0_33_082AE7CFEFA6960C804A9FE7366EB5A0Ll14anonymousTypesfMf_4namefMu_C5helloSSyF
+// CHECK-SIL: sil @$s9MacroUser03$s9A115User0033top_level_freestandingswift_DbGHjfMX56_0_33_082AE7CFEFA6960C804A9FE7366EB5A0Ll14anonymousTypesfMf_4namefMu_C5helloSSyF
 
 @main
 struct Main {
@@ -94,8 +90,6 @@ func testArbitraryAtGlobal() {
 }
 #endif
 
-// DIAG_BUFFERS-DAG: @__swiftmacro_9MacroUser0039top_level_freestanding_otherswift_jrGEmfMX12_17_33_7FDB3F9D78D0279543373AD342C3C331Ll9stringifyfMf1{{.*}}: warning: 'deprecated()' is deprecated
-// DIAG_BUFFERS-DAG: @__swiftmacro_9MacroUser0039top_level_freestanding_otherswift_jrGEmfMX16_17_33_7FDB3F9D78D0279543373AD342C3C331Ll9stringifyfMf2{{.*}}: warning: 'deprecated()' is deprecated
 
 #varValue
 
@@ -107,15 +101,31 @@ func testGlobalVariable() {
 
 // expected-note @+1 6 {{in expansion of macro 'anonymousTypes' here}}
 #anonymousTypes(causeErrors: true) { "foo" }
-// DIAG_BUFFERS-DAG: @__swiftmacro_9MacroUser0033top_level_freestandingswift_DbGHjfMX108_0_33_082AE7CFEFA6960C804A9FE7366EB5A0Ll14anonymousTypesfMf0_{{.*}}: warning: use of protocol 'Equatable' as a type must be written 'any Equatable'
-// DIAG_BUFFERS-DAG: @__swiftmacro_9MacroUser00142___swiftmacro_9MacroUser0033top_level_freestandingswift_DbGHjfMX108_0_33_082AE7CFEFA6960C804A9FE7366EB5A0Ll14anonymousTypesfMf0_swift_DAIABdjIbfMX23_2_33_082AE7CFEFA6960C804A9FE7366EB5A0Ll27introduceTypeCheckingErrorsfMf_{{.*}}: warning: use of protocol 'Hashable' as a type must be written 'any Hashable'
-
+/*
+expected-expansion@-2:1 {{
+  expected-warning@23:8{{same-type requirement makes generic parameter 'T' non-generic; this is an error in the Swift 6 language mode}}
+  expected-note@23:135{{'T' previously declared here}}
+  expected-warning@23:149{{use of protocol 'Equatable' as a type must be written 'any Equatable'; this will be an error in a future Swift language mode}}
+  expected-note@24:3 3{{in expansion of macro 'introduceTypeCheckingErrors' here}}
+  expected-expansion@24:3 {{
+    expected-warning@2:10{{same-type requirement makes generic parameter 'T' non-generic; this is an error in the Swift 6 language mode}}
+    expected-warning@2:259{{generic parameter 'T' shadows generic parameter from outer scope with the same name; this is an error in the Swift 6 language mode}}
+    expected-warning@2:273{{use of protocol 'Hashable' as a type must be written 'any Hashable'; this will be an error in a future Swift language mode}}
+  }}
+}}
+*/
 // expected-note @+1 2 {{in expansion of macro 'anonymousTypes' here}}
 #anonymousTypes { () -> String in
   // expected-warning @+1 {{use of protocol 'Equatable' as a type must be written 'any Equatable'}}
   _ = 0 as Equatable
   return "foo"
 }
+/*
+expected-expansion@-6:1{{
+  expected-warning@5:16{{use of protocol 'Equatable' as a type must be written 'any Equatable'; this will be an error in a future Swift language mode}}
+  expected-warning@20:16{{use of protocol 'Equatable' as a type must be written 'any Equatable'; this will be an error in a future Swift language mode}}
+}}
+*/
 
 #endif
 
@@ -145,3 +155,24 @@ struct S {
 #checkGeneric<String>()
 #checkGeneric2<String, Int>()
 #checkGenericHashableCodable<String, Int>()
+
+// Check that inout parameters are allowed in expression macros
+
+@freestanding(expression) macro functionCallWithInoutParam(_ v: inout Int)
+  = #externalMacro(module: "MacroDefinition", type: "VoidExpressionMacro")
+
+@freestanding(expression) macro functionCallWithTwoInoutParams(_ u: inout Int, _ v: inout Int)
+  = #externalMacro(module: "MacroDefinition", type: "VoidExpressionMacro")
+
+@freestanding(expression) macro functionCallWithInoutParamPlusOthers(
+  string: String, double: Double, _ v: inout Int)
+  = #externalMacro(module: "MacroDefinition", type: "VoidExpressionMacro")
+
+func testFunctionCallWithInoutParam() {
+  var a = 0
+  var b = 0
+  #functionCallWithInoutParam(&a)
+  #functionCallWithTwoInoutParams(&a, &b)
+  #functionCallWithInoutParamPlusOthers(string: "", double: 1.0, &a)
+}
+
diff --git a/test/Misc/expression_too_complex_2.swift b/test/Misc/expression_too_complex_2.swift
index eebb4c1b61027..196da7da0a53c 100644
--- a/test/Misc/expression_too_complex_2.swift
+++ b/test/Misc/expression_too_complex_2.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-memory-threshold 32000
+// RUN: %target-typecheck-verify-swift -solver-memory-threshold=32000
 // REQUIRES: OS=ios
 import UIKit
 class MyViewCell: UITableViewCell {
diff --git a/test/Misc/misc_diagnostics.swift b/test/Misc/misc_diagnostics.swift
index 6d27d411adcc5..d368a6f88d4d2 100644
--- a/test/Misc/misc_diagnostics.swift
+++ b/test/Misc/misc_diagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
@@ -56,7 +56,7 @@ class A {
     var a: MyArray<Int>
     init() {
         a = MyArray<Int // expected-error {{generic parameter 'Element' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}}
-       // expected-error@-1 {{binary operator '<' cannot be applied to operands of type 'MyArray<_>.Type' and 'Int.Type'}}
+       // expected-error@-1 {{binary operator '<' cannot be applied to operands of type 'MyArray<Element>.Type' and 'Int.Type'}}
        // expected-error@-2 {{cannot assign value of type 'Bool' to type 'MyArray<Int>'}}
     }
 }
diff --git a/test/Misc/prioritize_solver_memory_threshold.swift b/test/Misc/prioritize_solver_memory_threshold.swift
index 5eeff81b5edcd..ff36150d4c499 100644
--- a/test/Misc/prioritize_solver_memory_threshold.swift
+++ b/test/Misc/prioritize_solver_memory_threshold.swift
@@ -1,3 +1,3 @@
-// RUN: %target-typecheck-verify-swift -solver-memory-threshold 1
+// RUN: %target-typecheck-verify-swift -solver-memory-threshold=1
 
 func foo() { _ = 1 } // expected-error {{the compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions}}
diff --git a/test/Misc/serialized-diagnostics-prettyprint.swift b/test/Misc/serialized-diagnostics-prettyprint.swift
index d0e0cab3040d8..632f36f3d4712 100644
--- a/test/Misc/serialized-diagnostics-prettyprint.swift
+++ b/test/Misc/serialized-diagnostics-prettyprint.swift
@@ -1,14 +1,32 @@
-// RUN: rm -f %t.*
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
 
-// Test swift executable
-// RUN: %target-swift-frontend -typecheck -serialize-diagnostics-path %t.dia %s -verify
-// RUN: c-index-test -read-diagnostics %t.dia > %t.deserialized_diagnostics.txt 2>&1
-// RUN: %FileCheck --input-file=%t.deserialized_diagnostics.txt %s
+// RUN: %target-swift-frontend -emit-module %t/Lib.swift -module-name Lib -emit-module-path %t/Lib.swiftmodule
+// RUN: %target-swift-frontend -typecheck -I %t -serialize-diagnostics-path %t/diags.dia %t/Client.swift -verify -verify-ignore-unrelated
+// RUN: c-index-test -read-diagnostics %t/diags.dia > %t/diags.deserialized_diagnostics.txt 2>&1
+// RUN: %FileCheck --input-file=%t/diags.deserialized_diagnostics.txt %t/Client.swift
 
-var x = String.init // expected-error{{ambiguous use of 'init'}}
-// CHECK: {{.*[/\\]}}serialized-diagnostics-prettyprint.swift:[[@LINE-1]]:16: error: ambiguous use of 'init'
+//--- Lib.swift
 
-// CHECK: Swift.String.init:2:19: note: found this candidate
-// CHECK: CONTENTS OF FILE Swift.String.init:
-// CHECK: struct String {
-// CHECK:    public init(_ content: Substring.UnicodeScalarView)
+public struct S {
+  public init(a: String) {}
+  @discardableResult // We use @discardableResult here to give this init a distinct line number in the pretty print.
+  public init(b: Int) {}
+}
+
+//--- Client.swift
+
+import Lib
+
+var x = S.init // expected-error {{ambiguous use of 'init'}}
+// CHECK: {{.*[/\\]}}Client.swift:[[@LINE-1]]:11: error: ambiguous use of 'init'
+
+// FIXME: Currently we can't check for 'init(a:)' because c-index-test is
+// keying the source file contents on the buffer identifier, so we end up
+// with duplicated 'init(b:)'.
+
+// CHECK: Lib.S.init:3:10: note: found this candidate
+// CHECK:      CONTENTS OF FILE Lib.S.init:
+// CHECK:      struct S {
+// CHECK-NEXT:    @discardableResult
+// CHECK-NEXT:    public init(b: Int)
diff --git a/test/Misc/stats_dir_profiler.swift b/test/Misc/stats_dir_profiler.swift
index 96d294fbbfd90..0ddc6214a90f2 100644
--- a/test/Misc/stats_dir_profiler.swift
+++ b/test/Misc/stats_dir_profiler.swift
@@ -2,12 +2,12 @@
 // RUN: %empty-directory(%t/stats-events)
 // RUN: %empty-directory(%t/stats-entities)
 // RUN: %target-swiftc_driver -o %t/main -module-name main -stats-output-dir %t/stats-events %s -profile-stats-events -Xfrontend -fine-grained-timers
-// RUN: %target-swiftc_driver -o %t/main -module-name main -stats-output-dir %t/stats-entities %s -profile-stats-entities -Xfrontend -fine-grained-timers
+// %target-swiftc_driver -o %t/main -module-name main -stats-output-dir %t/stats-entities %s -profile-stats-entities -Xfrontend -fine-grained-timers
 
 // Need to use %long-tmp because in Windows the * may expand to a path longer
 // than 260 characters.
 // RUN: %FileCheck -check-prefix=EVENTS -input-file %long-tmp/stats-events/*.dir/Time.User.events %s
-// RUN: %FileCheck -check-prefix=ENTITIES -input-file %long-tmp/stats-entities/*.dir/Time.User.entities %s
+// %FileCheck -check-prefix=ENTITIES -input-file %long-tmp/stats-entities/*.dir/Time.User.entities %s
 
 // EVENTS: {{perform-sema;.*;typecheck-decl.* [0-9]+}}
 // ENTITIES: {{perform-sema;.*;TypeCheckFunctionBodyRequest bar\(\);typecheck-stmt.* [0-9]+}}
diff --git a/test/Misc/target-cpu.swift b/test/Misc/target-cpu.swift
index 89c7d4cd1be65..95bf1c18e0aa1 100644
--- a/test/Misc/target-cpu.swift
+++ b/test/Misc/target-cpu.swift
@@ -13,8 +13,8 @@
 // RUN: not %swift -typecheck -target armv7k-apple-watchos2 -Xcc -### %s 2>&1 | %FileCheck -check-prefix=WATCHTARGETCPU1 %s
 // WATCHTARGETCPU1: "-target-cpu" "cortex-a7"
 
-// RUN: not %swift -typecheck -target arm64-apple-watchos2 -Xcc -### %s 2>&1 | %FileCheck -check-prefix=WATCHTARGETCPU2 %s
-// WATCHTARGETCPU2: "-target-cpu" "apple-a7"
+// RUN: not %swift -typecheck -target arm64_32-apple-watchos2 -Xcc -### %s 2>&1 | %FileCheck -check-prefix=WATCHTARGETCPU2 %s
+// WATCHTARGETCPU2: "-target-cpu" "apple-s4"
 
 // RUN: not %swift -typecheck -target armv7s-apple-ios7 -Xcc -### %s 2>&1 | %FileCheck -check-prefix=TARGETCPU2 %s
 // TARGETCPU2: "-target-cpu" "swift"
diff --git a/test/Misc/verify-swift-feature-testing.test-sh b/test/Misc/verify-swift-feature-testing.test-sh
index 8713ae8fea865..df65d56b4e590 100755
--- a/test/Misc/verify-swift-feature-testing.test-sh
+++ b/test/Misc/verify-swift-feature-testing.test-sh
@@ -20,7 +20,9 @@ EXCEPTIONAL_FILES = [
     # Tests for ModuleInterfaceExportAs being ignored
     pathlib.Path("test/ModuleInterface/swift-export-as.swift"),
     # Uses the pseudo-feature AvailabilityMacro=
-    pathlib.Path("test/Sema/availability_define.swift"),
+    pathlib.Path("test/Availability/availability_define.swift"),
+    # Uses the pseudo-feature RequiresObjC=
+    pathlib.Path("test/Interop/SwiftToCxx/stdlib/foundation-type-not-exposed-by-default-to-cxx.swift"),
     # Tests behavior when you try to use a feature without enabling it
     pathlib.Path("test/attr/feature_requirement.swift"),
     # Tests completion with features both enabled and disabled
@@ -98,6 +100,7 @@ def find_matches(swift_src_root):
     # `-enable-upcoming-feature` in the test directories.
     output = subprocess.check_output(
         [
+            "git",
             "grep",
             "--extended-regexp",
             "--recursive",
@@ -111,6 +114,7 @@ def find_matches(swift_src_root):
             # Be careful to not use RUN with a colon after it or Lit will pick
             # it up.
             "RUN[:].*-enable-(experimental|upcoming)-feature",
+            "--",
             "test",
             "validation-test",
         ],
diff --git a/test/ModuleInterface/Inputs/lifetime_dependence.swift b/test/ModuleInterface/Inputs/lifetime_dependence.swift
index 8c04ab6867d72..15095a4861234 100644
--- a/test/ModuleInterface/Inputs/lifetime_dependence.swift
+++ b/test/ModuleInterface/Inputs/lifetime_dependence.swift
@@ -1,21 +1,3 @@
-@_unsafeNonescapableResult
-@_alwaysEmitIntoClient
-@_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable>(
-  _ dependent: consuming T, borrowing source: borrowing U) -> T {
-  dependent
-}
-
-@_unsafeNonescapableResult
-@_alwaysEmitIntoClient
-@_transparent
-@lifetime(copy source)
-internal func _overrideLifetime<T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable>(
-  _ dependent: consuming T, copying source: borrowing U) -> T {
-  dependent
-}
-
 public struct AnotherView : ~Escapable {
   @usableFromInline let _ptr: UnsafeRawBufferPointer
   @usableFromInline let _count: Int
@@ -69,13 +51,17 @@ public func consumeAndCreate(_ view: consuming BufferView) -> BufferView {
   return _overrideLifetime(bv, copying: view)
 }
 
+// FIXME: Filed rdar://150398673 ([nonescapable] allocbox-to-stack fails causing lifetime diagnostics to fail)
+// Remove _overrideLifetime when this is fixed.
 @inlinable
 @lifetime(copy this, copy that)
 public func deriveThisOrThat(_ this: consuming BufferView, _ that: consuming BufferView) -> BufferView {
   if (Int.random(in: 1..<100) == 0) {
-    return BufferView(this._ptr, this._count)
+    let thisView = BufferView(this._ptr, this._count)
+    return _overrideLifetime(thisView, copying: this)
   }
-  return BufferView(that._ptr, that._count)
+  let thatView = BufferView(that._ptr, that._count)
+  return _overrideLifetime(thatView, copying: that)
 }
 
 public struct Container {
@@ -91,3 +77,21 @@ extension Container {
     }
   }
 }
+
+// Test feature guard: NonescapableAccessorOnTrivial
+extension UnsafeMutableBufferPointer where Element: ~Copyable {
+  public var span: Span<Element> {
+    @lifetime(borrow self)
+    @_alwaysEmitIntoClient
+    get {
+      unsafe Span(_unsafeElements: self)
+    }
+  }
+  public var mutableSpan: MutableSpan<Element> {
+    @lifetime(borrow self)
+    @_alwaysEmitIntoClient
+    get {
+      unsafe MutableSpan(_unsafeElements: self)
+    }
+  }
+}
diff --git a/test/ModuleInterface/Inputs/lifetime_underscored_dependence.swift b/test/ModuleInterface/Inputs/lifetime_underscored_dependence.swift
new file mode 100644
index 0000000000000..bf9407c784652
--- /dev/null
+++ b/test/ModuleInterface/Inputs/lifetime_underscored_dependence.swift
@@ -0,0 +1,79 @@
+public struct AnotherView : ~Escapable {
+  @usableFromInline let _ptr: UnsafeRawBufferPointer
+  @usableFromInline let _count: Int
+  @_lifetime(borrow ptr)
+  internal init(_ ptr: UnsafeRawBufferPointer, _ count: Int) {
+    self._ptr = ptr
+    self._count = count
+  }
+}
+
+public struct BufferView : ~Escapable {
+  @usableFromInline let _ptr: UnsafeRawBufferPointer
+  @usableFromInline let _count: Int
+  @usableFromInline 
+  @_lifetime(borrow ptr)
+  internal init(_ ptr: UnsafeRawBufferPointer, _ count: Int) {
+    self._ptr = ptr
+    self._count = count
+  }
+
+  @inlinable
+  @_lifetime(borrow a)
+  internal init(_ ptr: UnsafeRawBufferPointer, _ a: borrowing Array<Int>) {
+    let bv = BufferView(ptr, a.count)
+    self = _overrideLifetime(bv, borrowing: a)
+  }
+  @inlinable
+  @_lifetime(copy a)
+  internal init(_ ptr: UnsafeRawBufferPointer, _ a: consuming AnotherView) {
+    let bv = BufferView(ptr, a._count)
+    self = _overrideLifetime(bv, copying: a)
+  }
+}
+
+@inlinable
+@_lifetime(copy x)
+public func derive(_ x: consuming BufferView) -> BufferView {
+  let pointer = x._ptr
+  let bv = BufferView(pointer, x._count)
+  return _overrideLifetime(bv, copying: x)
+}
+
+@inlinable
+public func use(_ x: consuming BufferView) {}
+
+@inlinable
+@_lifetime(copy view)
+public func consumeAndCreate(_ view: consuming BufferView) -> BufferView {
+  let pointer = view._ptr
+  let bv = BufferView(pointer, view._count)
+  return _overrideLifetime(bv, copying: view)
+}
+
+// FIXME: Filed rdar://150398673 ([nonescapable] allocbox-to-stack fails causing lifetime diagnostics to fail)
+// Remove _overrideLifetime when this is fixed.
+@inlinable
+@_lifetime(copy this, copy that)
+public func deriveThisOrThat(_ this: consuming BufferView, _ that: consuming BufferView) -> BufferView {
+  if (Int.random(in: 1..<100) == 0) {
+    let thisView = BufferView(this._ptr, this._count)
+    return _overrideLifetime(thisView, copying: this)
+  }
+  let thatView = BufferView(that._ptr, that._count)
+  return _overrideLifetime(thatView, copying: that)
+}
+
+public struct Container {
+  var buffer: UnsafeRawBufferPointer
+  var object: AnyObject
+}
+
+extension Container {
+  public var storage: BufferView {
+    get {
+      let view = BufferView(buffer, 1)
+      return _overrideLifetime(view, borrowing: self)
+    }
+  }
+}
diff --git a/test/ModuleInterface/Inputs/objc_implementation/objc_implementation.h b/test/ModuleInterface/Inputs/objc_implementation/objc_implementation.h
index aff13897e623f..93a68662595da 100644
--- a/test/ModuleInterface/Inputs/objc_implementation/objc_implementation.h
+++ b/test/ModuleInterface/Inputs/objc_implementation/objc_implementation.h
@@ -4,6 +4,7 @@
 
 - (nonnull instancetype)init;
 
+@property (readonly) int letProperty1;
 @property (assign) int implProperty;
 
 - (void)mainMethod:(int)param;
diff --git a/test/ModuleInterface/ModuleCache/cxx-interop-caching.swift b/test/ModuleInterface/ModuleCache/cxx-interop-caching.swift
new file mode 100644
index 0000000000000..788ca0c5d4810
--- /dev/null
+++ b/test/ModuleInterface/ModuleCache/cxx-interop-caching.swift
@@ -0,0 +1,35 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t --leading-lines
+
+/// Build one library module
+// RUN: %target-swift-frontend -parse-stdlib -emit-module \
+// RUN:   -o %t/Lib.swiftmodule %t/Lib.swift \
+// RUN:   -emit-module-interface-path %t/Lib.swiftinterface \
+// RUN:   -swift-version 5 -enable-library-evolution -module-name Lib
+
+/// Distributed scenario with only the swiftinterface
+// RUN: rm %t/Lib.swiftmodule
+// RUN: %empty-directory(%t/ModuleCache)
+
+/// Rebuild from the swiftinterface just once for non-C++ users
+// RUN: %target-swift-frontend -parse-stdlib -typecheck %t/Rebuild.swift -I %t \
+// RUN:   -module-cache-path %t/ModuleCache -Rmodule-interface-rebuild -verify
+// RUN: %target-swift-frontend -parse-stdlib -typecheck %t/UseExisting.swift -I %t \
+// RUN:   -module-cache-path %t/ModuleCache -Rmodule-interface-rebuild -verify
+
+/// Rebuild from the swiftinterface just once for C++ users
+// RUN: %target-swift-frontend -parse-stdlib -typecheck %t/Rebuild.swift -I %t \
+// RUN:   -module-cache-path %t/ModuleCache -Rmodule-interface-rebuild -verify \
+// RUN:   -cxx-interoperability-mode=default
+// RUN: %target-swift-frontend -parse-stdlib -typecheck %t/UseExisting.swift -I %t \
+// RUN:   -module-cache-path %t/ModuleCache -Rmodule-interface-rebuild -verify \
+// RUN:   -cxx-interoperability-mode=default
+
+//--- Lib.swift
+public func publicFunction() {}
+
+//--- UseExisting.swift
+import Lib
+
+//--- Rebuild.swift
+import Lib // expected-remark {{rebuilding module 'Lib' from interface}}
diff --git a/test/ModuleInterface/attr-inline-always.swift b/test/ModuleInterface/attr-inline-always.swift
new file mode 100644
index 0000000000000..c5d24654b780c
--- /dev/null
+++ b/test/ModuleInterface/attr-inline-always.swift
@@ -0,0 +1,21 @@
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %s -module-name attrs \
+// RUN:  -enable-experimental-feature InlineAlways \
+// RUN:  -emit-private-module-interface-path %t.private.swiftinterface
+
+// RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -module-name attrs \
+// RUN:  -enable-experimental-feature InlineAlways
+// RUN: %target-swift-typecheck-module-from-interface(%t.private.swiftinterface) -module-name attrs \
+// RUN:  -enable-experimental-feature InlineAlways
+
+// RUN: %FileCheck %s --check-prefixes CHECK --input-file %t.swiftinterface
+// RUN: %FileCheck %s --check-prefixes CHECK --input-file %t.private.swiftinterface
+
+// REQUIRES: swift_feature_InlineAlways
+
+// CHECK: #if compiler(>=5.3) && $InlineAlways
+// CHECK: @inline(always) public func inlineAlwaysFunc() {}
+// CHECK: #else
+// CHECK: @inline(__always) @inlinable public func inlineAlwaysFunc() {}
+// CHECK: #endif
+@inline(always)
+public func inlineAlwaysFunc() {}
diff --git a/test/ModuleInterface/attrs.swift b/test/ModuleInterface/attrs.swift
index effaa641cc9b7..76ae8d6d28a3b 100644
--- a/test/ModuleInterface/attrs.swift
+++ b/test/ModuleInterface/attrs.swift
@@ -1,7 +1,5 @@
 // RUN: %target-swift-emit-module-interface(%t.swiftinterface) %s -module-name attrs \
-// RUN:  -emit-private-module-interface-path %t.private.swiftinterface \
-// RUN:  -enable-experimental-feature ABIAttribute \
-// RUN:  -enable-experimental-feature ExecutionAttribute
+// RUN:  -emit-private-module-interface-path %t.private.swiftinterface
 
 // RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -module-name attrs
 // RUN: %target-swift-typecheck-module-from-interface(%t.private.swiftinterface) -module-name attrs
@@ -9,9 +7,6 @@
 // RUN: %FileCheck %s --check-prefixes CHECK,PUBLIC-CHECK --input-file %t.swiftinterface
 // RUN: %FileCheck %s --check-prefixes CHECK,PRIVATE-CHECK --input-file %t.private.swiftinterface
 
-// REQUIRES: swift_feature_ABIAttribute
-// REQUIRES: swift_feature_ExecutionAttribute
-
 // CHECK: @_transparent public func glass() -> Swift.Int { return 0 }{{$}}
 @_transparent public func glass() -> Int { return 0 }
 
@@ -40,7 +35,7 @@ internal func __specialize_someGenericFunction<T>(_ t: T) -> Int {
 
 @abi(func __abi__abiAttrOnFunction(param: Int))
 public func abiAttrOnFunction(param: Int) {}
-// CHECK: #if {{.*}} $ABIAttribute
+// CHECK: #if {{.*}} $ABIAttributeSE0479
 // CHECK: @abi(func __abi__abiAttrOnFunction(param: Swift.Int))
 // CHECK: public func abiAttrOnFunction(param: Swift.Int)
 // CHECK: #else
@@ -50,7 +45,7 @@ public func abiAttrOnFunction(param: Int) {}
 
 @abi(let __abi__abiAttrOnVar: Int)
 public var abiAttrOnVar: Int = 42
-// CHECK: #if {{.*}} $ABIAttribute
+// CHECK: #if {{.*}} $ABIAttributeSE0479
 // CHECK: @abi(var __abi__abiAttrOnVar: Swift.Int)
 // CHECK: public var abiAttrOnVar: Swift.Int
 // CHECK: #else
@@ -59,7 +54,7 @@ public var abiAttrOnVar: Int = 42
 // CHECK: #endif
 
 public struct MutatingTest {
-  // CHECK: #if {{.*}} $ABIAttribute
+  // CHECK: #if {{.*}} $ABIAttributeSE0479
   // CHECK: @abi(mutating func abiMutFunc())
   // CHECK: public mutating func abiMutFunc()
   // CHECK: #else
@@ -70,14 +65,14 @@ public struct MutatingTest {
   public mutating func abiMutFunc() {}
 }
 
-// PUBLIC-CHECK-NOT: #if {{.*}} $ABIAttribute
+// PUBLIC-CHECK-NOT: #if {{.*}} $ABIAttributeSE0479
 // PUBLIC-CHECK-NOT: @abi(func abiSpiFunc())
 // PUBLIC-CHECK-NOT: public func abiSpiFunc()
 // PUBLIC-CHECK-NOT: #else
 // PUBLIC-CHECK-NOT: @_silgen_name("$s5attrs10abiSpiFuncyyF")
 // PUBLIC-CHECK-NOT: public func abiSpiFunc()
 // PUBLIC-CHECK-NOT: #endif
-// PRIVATE-CHECK: #if {{.*}} $ABIAttribute
+// PRIVATE-CHECK: #if {{.*}} $ABIAttributeSE0479
 // PRIVATE-CHECK: @abi(func abiSpiFunc())
 // PRIVATE-CHECK: public func abiSpiFunc()
 // PRIVATE-CHECK: #else
@@ -87,10 +82,29 @@ public struct MutatingTest {
 @abi(func abiSpiFunc())
 @_spi(spiGroup) public func abiSpiFunc() {}
 
-@execution(concurrent)
+// We should print feature guards outside, but not inside, an @abi attribute.
+@abi(func sendingABI() -> sending Any?)
+public func sendingABI() -> Any? { nil }
+// CHECK: #if {{.*}} && $ABIAttributeSE0479
+// CHECK: @abi(func sendingABI() -> sending Any?)
+// CHECK: public func sendingABI() -> Any?
+// CHECK: @_silgen_name("$s5attrs10sendingABIypSgyF")
+// CHECK: public func sendingABI() -> Any?
+// CHECK: #endif
+
+@concurrent
 public func testExecutionConcurrent() async {}
-// CHECK: @execution(concurrent) public func testExecutionConcurrent() async
+// CHECK: @concurrent public func testExecutionConcurrent() async
 
-@execution(caller)
+nonisolated(nonsending)
 public func testExecutionCaller() async {}
-// CHECK: @execution(caller) public func testExecutionCaller() async
+// CHECK: nonisolated(nonsending) public func testExecutionCaller() async
+
+public struct TestPlacementOfAttrsAndSpecifiers {
+  // CHECK: public func test1<T>(_: sending @autoclosure () -> T)
+  public func test1<T>(_: sending @autoclosure () -> T) {}
+  // CHECK: public func test2<T>(_: borrowing @autoclosure () -> T)
+  public func test2<T>(_: borrowing @autoclosure () -> T) {}
+  // CHECK: public func test3<T>(_: inout () async -> T)
+  public func test3<T>(_: inout () async -> T) {}
+}
diff --git a/test/ModuleInterface/attrs_objc.swift b/test/ModuleInterface/attrs_objc.swift
index 37cb78318be05..0f8fd5b1f2ca0 100644
--- a/test/ModuleInterface/attrs_objc.swift
+++ b/test/ModuleInterface/attrs_objc.swift
@@ -1,19 +1,17 @@
 // RUN: %target-swift-emit-module-interface(%t.swiftinterface) %s \
-// RUN:  -enable-objc-interop -module-name attrs_objc \
-// RUN:  -enable-experimental-feature ABIAttribute
+// RUN:  -enable-objc-interop -module-name attrs_objc
 
 // RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -module-name attrs_objc
 
 // RUN: %FileCheck %s --input-file %t.swiftinterface
 
 // REQUIRES: objc_interop
-// REQUIRES: swift_feature_ABIAttribute
 
 import Foundation
 
 @objcMembers
 public class ObjCTest: NSObject {
-  // CHECK: #if {{.*}} $ABIAttribute
+  // CHECK: #if {{.*}} $ABIAttributeSE0479
   // CHECK: @abi(func abiObjCFunc())
   // CHECK: @objc public func abiObjCFunc()
   // CHECK: #else
@@ -23,7 +21,7 @@ public class ObjCTest: NSObject {
   @abi(func abiObjCFunc())
   @objc public func abiObjCFunc() {}
 
-  // CHECK: #if {{.*}} $ABIAttribute
+  // CHECK: #if {{.*}} $ABIAttributeSE0479
   // CHECK: @abi(func abiImplicitObjCFunc())
   // CHECK: @objc public func abiImplicitObjCFunc()
   // CHECK: #else
@@ -33,7 +31,7 @@ public class ObjCTest: NSObject {
   @abi(func abiImplicitObjCFunc())
   public func abiImplicitObjCFunc() {}
 
-  // CHECK: #if {{.*}} $ABIAttribute
+  // CHECK: #if {{.*}} $ABIAttributeSE0479
   // CHECK: @abi(func abiIBActionFunc(_: Any))
   // CHECK: @objc @IBAction @_Concurrency.MainActor @preconcurrency public func abiIBActionFunc(_: Any)
   // CHECK: #else
diff --git a/test/ModuleInterface/availability-canonical-version.swift b/test/ModuleInterface/availability-canonical-version.swift
new file mode 100644
index 0000000000000..4f08f601c9118
--- /dev/null
+++ b/test/ModuleInterface/availability-canonical-version.swift
@@ -0,0 +1,34 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-emit-module-interface(%t/Module.swiftinterface) %s
+// RUN: %target-swift-typecheck-module-from-interface(%t/Module.swiftinterface)
+// RUN: %FileCheck %s < %t/Module.swiftinterface
+
+@available(macOS 10.16, iOS 10.16, watchOS 10.16, tvOS 10.16, *)
+public func introduced10_16() { }
+// CHECK: @available(macOS 11.0, iOS 10.16, watchOS 10.16, tvOS 10.16, *)
+// CHECK-NEXT: public func introduced10_16()
+
+@available(OSX 11.0, iOS 11.0, watchOS 11.0, tvOS 11.0, *)
+public func introduced11_0() { }
+// CHECK-NEXT: @available(macOS 11.0, iOS 11.0, watchOS 11.0, tvOS 11.0, *)
+// CHECK-NEXT: public func introduced11_0()
+
+@available(macOS 16.0, iOS 19.0, macCatalyst 19.0, watchOS 12.0, tvOS 19.0, visionOS 3.0, *)
+public func introducedInVersionsMappingTo26_0() { }
+// CHECK-NEXT: @available(macOS 26.0, iOS 26.0, macCatalyst 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0, *)
+// CHECK-NEXT: public func introducedInVersionsMappingTo26_0()
+
+@available(macOS 17.0, iOS 20.0, macCatalyst 20.0, watchOS 13.0, tvOS 20.0, visionOS 4.0, *)
+public func introducedInInvalidVersionsMappingTo27_0() { }
+// CHECK-NEXT: @available(macOS 27.0, iOS 27.0, macCatalyst 27.0, watchOS 27.0, tvOS 27.0, visionOS 27.0, *)
+// CHECK-NEXT: public func introducedInInvalidVersionsMappingTo27_0()
+
+@available(macOS 19.1.1, iOS 21, macCatalyst 21.0, watchOS 14.5.1, tvOS 21.2.3, visionOS 4.0.1, *)
+public func introducedInInvalidVersionsWithVaryingComponents() { }
+// CHECK-NEXT: @available(macOS 29.1.1, iOS 28, macCatalyst 28.0, watchOS 28.5.1, tvOS 28.2.3, visionOS 27.0.1, *)
+// CHECK-NEXT: public func introducedInInvalidVersionsWithVaryingComponents()
+
+@available(macOS 26.0, iOS 26.0, macCatalyst 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0, *)
+public func introduced26_0() { }
+// CHECK-NEXT: @available(macOS 26.0, iOS 26.0, macCatalyst 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0, *)
+// CHECK-NEXT: public func introduced26_0()
diff --git a/test/ModuleInterface/availability-macos-canonical-version.swift b/test/ModuleInterface/availability-macos-canonical-version.swift
deleted file mode 100644
index 0c73c2cc43068..0000000000000
--- a/test/ModuleInterface/availability-macos-canonical-version.swift
+++ /dev/null
@@ -1,19 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: %target-swift-emit-module-interface(%t/Module.swiftinterface) %s
-// RUN: %target-swift-typecheck-module-from-interface(%t/Module.swiftinterface)
-// RUN: %FileCheck %s < %t/Module.swiftinterface
-
-// REQUIRES: OS=macosx
-
-@available(macOS 10.16, *)
-public func introduced10_16() { }
-// CHECK: @available(macOS 11.0, *)
-// CHECK-NEXT: public func introduced10_16()
-
-
-@available(OSX 11.0, *)
-public func introduced11_0() { }
-// CHECK-NEXT: @available(macOS 11.0, *)
-// CHECK-NEXT: public func introduced11_0()
-
-
diff --git a/test/ModuleInterface/availability-scopes.swift b/test/ModuleInterface/availability-scopes.swift
new file mode 100644
index 0000000000000..2985d88ada8e2
--- /dev/null
+++ b/test/ModuleInterface/availability-scopes.swift
@@ -0,0 +1,10 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-emit-module-interface(%t/Test.swiftinterface) %s -module-name Test
+// RUN: %target-swift-typecheck-module-from-interface(%t/Test.swiftinterface) -module-name Test -dump-availability-scopes 2>&1 | %FileCheck --strict-whitespace %s
+// RUN: %target-swift-frontend -compile-module-from-interface %t/Test.swiftinterface -o /dev/null -module-name Test -dump-availability-scopes 2>&1 | %FileCheck --strict-whitespace %s
+
+// CHECK: {{^}}(root {{.*}} file={{.*}}{{/|\\}}availability-scopes.swift.tmp{{/|\\}}Test.swiftinterface
+// CHECK: {{^}}  (decl {{.*}}unavailable=* decl=unavailable()
+@available(*, unavailable)
+public func unavailable() { }
diff --git a/test/ModuleInterface/availability_custom_domains.swift b/test/ModuleInterface/availability_custom_domains.swift
new file mode 100644
index 0000000000000..eb76bbaac0444
--- /dev/null
+++ b/test/ModuleInterface/availability_custom_domains.swift
@@ -0,0 +1,30 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-emit-module-interface(%t/Test.swiftinterface) %s \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -module-name Test
+
+// RUN: %target-swift-typecheck-module-from-interface(%t/Test.swiftinterface) \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -module-name Test
+
+// RUN: %FileCheck %s < %t/Test.swiftinterface
+
+// REQUIRES: swift_feature_CustomAvailability
+
+import Oceans // re-exports Rivers
+
+// CHECK-NOT:  $CustomAvailability
+
+// CHECK:      @available(Colorado)
+// CHECK-NEXT: public func availableInColorado()
+@available(Colorado)
+public func availableInColorado() { }
+
+// CHECK:      @available(Arctic, unavailable)
+// CHECK-NEXT: @available(Pacific)
+// CHECK-NEXT: public func unavailableInArcticButAvailableInPacific()
+@available(Arctic, unavailable)
+@available(Pacific)
+public func unavailableInArcticButAvailableInPacific() { }
diff --git a/test/ModuleInterface/availability_custom_domains_library_level_api.swift b/test/ModuleInterface/availability_custom_domains_library_level_api.swift
new file mode 100644
index 0000000000000..ff96b2c684bf1
--- /dev/null
+++ b/test/ModuleInterface/availability_custom_domains_library_level_api.swift
@@ -0,0 +1,120 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend -emit-module %s \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -experimental-spi-only-imports \
+// RUN:   -enable-library-evolution -swift-version 5 -library-level api \
+// RUN:   -package-name TestPackage -module-name Test \
+// RUN:   -emit-module-interface-path %t/Test.swiftinterface \
+// RUN:   -emit-private-module-interface-path %t/Test.private.swiftinterface \
+// RUN:   -emit-package-module-interface-path %t/Test.package.swiftinterface
+
+// RUN: %target-swift-typecheck-module-from-interface(%t/Test.swiftinterface) \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -module-name Test
+
+// RUN: %target-swift-typecheck-module-from-interface(%t/Test.private.swiftinterface) \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -module-name Test
+
+// RUN: %target-swift-typecheck-module-from-interface(%t/Test.package.swiftinterface) \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -module-name Test
+
+// RUN: %FileCheck %s --check-prefixes=CHECK --input-file %t/Test.swiftinterface
+// RUN: %FileCheck %s --check-prefixes=CHECK-PUBLIC --input-file %t/Test.swiftinterface
+// RUN: %FileCheck %s --check-prefixes=CHECK,CHECK-NONPUBLIC --input-file %t/Test.private.swiftinterface
+// RUN: %FileCheck %s --check-prefixes=CHECK,CHECK-NONPUBLIC --input-file %t/Test.package.swiftinterface
+
+// REQUIRES: swift_feature_CustomAvailability
+
+import Lakes
+@_spiOnly import Seas
+
+// CHECK:                 @available(Salt)
+// CHECK:                 public func availableInPublicEnabledDomain()
+@available(Salt)
+public func availableInPublicEnabledDomain() { }
+
+// CHECK:                 @available(Erie)
+// CHECK:                 public func availableInPublicDisabledDomain()
+@available(Erie)
+public func availableInPublicDisabledDomain() { }
+
+// CHECK:                 @available(Huron)
+// CHECK:                 public func availableInPublicDynamicDomain()
+@available(Huron)
+public func availableInPublicDynamicDomain() { }
+
+// CHECK:                 @available(Salt, unavailable)
+// CHECK:                 public func unavailableInPublicEnabledDomain()
+@available(Salt, unavailable)
+public func unavailableInPublicEnabledDomain() { }
+
+// CHECK:                 @available(Erie, unavailable)
+// CHECK:                 public func unavailableInPublicDisabledDomain()
+@available(Erie, unavailable)
+public func unavailableInPublicDisabledDomain() { }
+
+// CHECK:                 @available(Huron, unavailable)
+// CHECK:                 public func unavailableInPublicDynamicDomain()
+@available(Huron, unavailable)
+public func unavailableInPublicDynamicDomain() { }
+
+// CHECK-NONPUBLIC:       @available(Baltic)
+// CHECK-PUBLIC-NOT:      Baltic
+// CHECK-LABEL:           public func availableInSPIOnlyEnabledDomain()
+@available(Baltic)
+public func availableInSPIOnlyEnabledDomain() { }
+
+// CHECK-NONPUBLIC:       @available(Mediterranean)
+// CHECK-NONPUBLIC-LABEL: public func availableInSPIOnlyDisabledDomain_Secret()
+// CHECK-PUBLIC-NOT:      Mediterranean
+// CHECK-PUBLIC-NOT:      availableInSPIOnlyDisabledDomain_Secret
+@available(Mediterranean)
+public func availableInSPIOnlyDisabledDomain_Secret() { }
+
+// CHECK-NONPUBLIC:       @available(Aegean)
+// CHECK-PUBLIC-NOT:      Aegean
+// CHECK-LABEL:           public func availableInSPIOnlyDynamicDomain()
+@available(Aegean)
+public func availableInSPIOnlyDynamicDomain() { }
+
+// CHECK-NONPUBLIC:       @available(Baltic, unavailable)
+// CHECK-NONPUBLIC-LABEL: public func unavailableInSPIOnlyEnabledDomain_Secret()
+// CHECK-PUBLIC-NOT:      Baltic
+// CHECK-PUBLIC-NOT:      unavailableInSPIOnlyEnabledDomain_Secret
+@available(Baltic, unavailable)
+public func unavailableInSPIOnlyEnabledDomain_Secret() { }
+
+// CHECK-NONPUBLIC:       @available(Mediterranean, unavailable)
+// CHECK-PUBLIC-NOT:      Mediterranean
+// CHECK-LABEL:           public func unavailableInSPIOnlyDisabledDomain()
+@available(Mediterranean, unavailable)
+public func unavailableInSPIOnlyDisabledDomain() { }
+
+// CHECK:                 @available(*, unavailable)
+// CHECK-NONPUBLIC:       @available(Baltic)
+// CHECK-PUBLIC-NOT:      Baltic
+// CHECK-LABEL:           public func availableInSPIOnlyEnabledDomainAndUnavailableUniversally()
+@available(*, unavailable)
+@available(Baltic)
+public func availableInSPIOnlyEnabledDomainAndUnavailableUniversally() { }
+
+// CHECK-NONPUBLIC:       @available(*, unavailable)
+// CHECK-NONPUBLIC:       @available(Mediterranean)
+// CHECK-NONPUBLIC-LABEL: public func availableInSPIOnlyDisabledDomainAndUnavailableUniversally_Secret()
+// CHECK-PUBLIC-NOT:      Mediterranean
+// CHECK-PUBLIC-NOT:      availableInSPIOnlyDisabledDomainAndUnavailableUniversally_Secret
+@available(*, unavailable)
+@available(Mediterranean)
+public func availableInSPIOnlyDisabledDomainAndUnavailableUniversally_Secret() { }
+
+// CHECK:                 @available(*, unavailable)
+// CHECK-NONPUBLIC:       @available(Aegean)
+// CHECK-PUBLIC-NOT:      Aegean
+// CHECK-LABEL:           public func availableInSPIOnlyDynamicDomainAndUnavailableUniversally()
+@available(*, unavailable)
+@available(Aegean)
+public func availableInSPIOnlyDynamicDomainAndUnavailableUniversally() { }
diff --git a/test/ModuleInterface/back-deployed-attr.swift b/test/ModuleInterface/back-deployed-attr.swift
index 4b6692cf13146..22c767d0d39f0 100644
--- a/test/ModuleInterface/back-deployed-attr.swift
+++ b/test/ModuleInterface/back-deployed-attr.swift
@@ -72,6 +72,21 @@ public func backDeployTopLevelFunc_macOS() -> Int {
 #endif
 }
 
+// CHECK: @backDeployed(before: macOS 26.0, iOS 26.0, tvOS 26.0, watchOS 26.0, visionOS 26.0)
+// CHECK: public func backDeployedBeforeVersionsMappingTo26() -> Swift.Int { return 26 }
+@backDeployed(before: macOS 16.0, iOS 19.0, tvOS 19.0, watchOS 12.0, visionOS 3.0)
+public func backDeployedBeforeVersionsMappingTo26() -> Int { return 26 }
+
+// CHECK: @backDeployed(before: macOS 27.0, iOS 27.0, tvOS 27.0, watchOS 27.0, visionOS 27.0)
+// CHECK: public func backDeployedBeforeVersionsMappingTo27() -> Swift.Int { return 27 }
+@backDeployed(before: macOS 17.0, iOS 20.0, tvOS 20.0, watchOS 13.0, visionOS 4.0)
+public func backDeployedBeforeVersionsMappingTo27() -> Int { return 27 }
+
+// CHECK: @backDeployed(before: macOS 26.0, iOS 26.0, tvOS 26.0, watchOS 26.0, visionOS 26.0)
+// CHECK: public func backDeployedBefore26() -> Swift.Int { return 26 }
+@backDeployed(before: macOS 26.0, iOS 26.0, tvOS 26.0, watchOS 26.0, visionOS 26.0)
+public func backDeployedBefore26() -> Int { return 26 }
+
 // MARK: - Availability macros
 
 // CHECK: @backDeployed(before: macOS 12.1)
diff --git a/test/ModuleInterface/bitwise_copyable_stdlib.swift b/test/ModuleInterface/bitwise_copyable_stdlib.swift
index d5f48cd05d6dc..ddda1a7d38fd4 100644
--- a/test/ModuleInterface/bitwise_copyable_stdlib.swift
+++ b/test/ModuleInterface/bitwise_copyable_stdlib.swift
@@ -3,19 +3,10 @@
 // RUN: %FileCheck %s < %t.swiftinterface
 // RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -parse-stdlib -module-name Swift
 
-// CHECK:      #if compiler(>=5.3) && $BitwiseCopyable2
-// CHECK-NEXT: public protocol BitwiseCopyable {
+// CHECK:      public protocol BitwiseCopyable {
 // CHECK-NEXT: }
-// CHECK-NEXT: #else
-// CHECK-NEXT: public protocol _BitwiseCopyable {
-// CHECK-NEXT: }
-// CHECK-NEXT: #endif
 
-// CHECK:      #if compiler(>=5.3) && $BitwiseCopyable2
 // CHECK-NEXT: public typealias _BitwiseCopyable = Swift.BitwiseCopyable
-// CHECK-NEXT: #else
-// CHECK-NEXT: public typealias BitwiseCopyable = Swift._BitwiseCopyable
-// CHECK-NEXT: #endif
 public protocol BitwiseCopyable {}
 public typealias _BitwiseCopyable = BitwiseCopyable
 
diff --git a/test/ModuleInterface/build-alternative-interface.swift b/test/ModuleInterface/build-alternative-interface.swift
index 3cae254ce79a3..ca1ada1188789 100644
--- a/test/ModuleInterface/build-alternative-interface.swift
+++ b/test/ModuleInterface/build-alternative-interface.swift
@@ -20,7 +20,7 @@
 // RUN: echo "messmessmess" >> %t/inputs/Foo.swiftinterface
 // RUN: echo "messmessmess" >> %t/inputs/Bar.swiftinterface
 
-// RUN: %target-typecheck-verify-swift -disable-implicit-concurrency-module-import -I %t/inputs -backup-module-interface-path %t/alternative-inputs -module-cache-path %t/module-cache
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-implicit-concurrency-module-import -I %t/inputs -backup-module-interface-path %t/alternative-inputs -module-cache-path %t/module-cache
 
 // RUN: touch -t 201401240005 %t/inputs/Bar.swiftinterface
 // RUN: %target-swift-frontend-typecheck -disable-implicit-concurrency-module-import -I %t/inputs -backup-module-interface-path %t/alternative-inputs -module-cache-path %t/module-cache -Rmodule-interface-rebuild %s &> %t/remarks.txt
diff --git a/test/ModuleInterface/canonicalized-os-version.swift b/test/ModuleInterface/canonicalized-os-version.swift
new file mode 100644
index 0000000000000..f8137024b3478
--- /dev/null
+++ b/test/ModuleInterface/canonicalized-os-version.swift
@@ -0,0 +1,53 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: split-file %s %t
+
+// REQUIRES: OS=macosx || OS=maccatalyst
+
+// First, test that the swift interface with an invalid os version behaves fine.
+// RUN: %target-swift-typecheck-module-from-interface(%t/Modules/Simple.swiftmodule/arm64-apple-macos.swiftinterface) -module-name Simple 
+
+// Next, build transitive dependencies in zippered mode.
+// RUN: %target-swift-frontend -module-name input %t/input.swift -target arm64-apple-macosx50.1 -target-variant arm64-apple-ios50.1-macabi -I%t/Modules -scan-dependencies -module-cache-path %t/module-cache-path -o %t/deps.json 2>&1 | Filecheck  --allow-empty --implicit-check-not warning: --implicit-check-not error: %s
+// RUN: %validate-json %t/deps.json | %FileCheck %s --check-prefix=DEPS
+
+DEPS-NOT:   "arm64-apple-macos16.4"
+DEPS-NOT:   "arm64-apple-ios22.0-macabi"
+DEPS:       "arm64-apple-macos26.4"
+
+//--- Modules/Simple.swiftmodule/arm64-apple-macos.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -target arm64-apple-macos16.4 
+public struct S {
+}
+
+//--- Modules/Simple.swiftmodule/arm64-apple-ios-macabi.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -target arm64-apple-ios22.0-macabi
+public struct S {
+}
+
+//--- Modules/module.modulemap
+module ClangDep {
+  header "ClangDep.h"
+  export *
+}
+
+//--- Modules/ClangDep.h
+typedef int my_int;
+
+
+//--- Modules/Interopt.swiftmodule/arm64-apple-macos.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -target arm64-apple-macos16.4  
+import Simple
+import ClangDep
+
+//--- Modules/Interopt.swiftmodule/arm64-apple-ios-macabi.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -target arm64-apple-ios22.0-macabi  
+import Simple
+import ClangDep
+
+//--- input.swift
+import Interopt
diff --git a/test/ModuleInterface/cdecl-swiftinterface.swift b/test/ModuleInterface/cdecl-swiftinterface.swift
new file mode 100644
index 0000000000000..3e79e92f988f7
--- /dev/null
+++ b/test/ModuleInterface/cdecl-swiftinterface.swift
@@ -0,0 +1,57 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t --leading-lines
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   -emit-module %t/Lib.swift -o %t -I %t \
+// RUN:   -swift-version 6 -enable-library-evolution \
+// RUN:   -emit-module-interface-path %t/Lib.swiftinterface \
+// RUN:   -enable-experimental-feature CDecl \
+// RUN:   -enable-experimental-feature CImplementation
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %t \
+// RUN:   -typecheck-module-from-interface %t/Lib.swiftinterface
+
+// RUN: %FileCheck %s --input-file %t/Lib.swiftinterface
+
+// REQUIRES: objc_interop
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: swift_feature_CImplementation
+
+//--- module.modulemap
+module Lib {
+    header "Lib.h"
+}
+
+//--- Lib.h
+extern void cImplFunc();
+extern void objcImplFunc();
+
+//--- Lib.swift
+@_exported import Lib
+import Foundation
+
+/// Don't print the implementation functions.
+// CHECK-NOT: @implementation
+// CHECK-NOT: ImplFunc
+
+@c @implementation
+public func cImplFunc() { }
+
+@_cdecl("objcImplFunc") @implementation
+public func objcImplFunc() { }
+
+/// Print other @c functions.
+@c
+public func bareCDecl() {}
+// CHECK: @c
+// CHECK-NEXT: public func bareCDecl
+
+@c(c_name)
+public func namedCDecl() {}
+// CHECK: @c(c_name)
+// CHECK-NEXT: public func namedCDecl
+
+@_cdecl("objc_name")
+public func namedLegacyCDecl() {}
+// CHECK: @_cdecl("objc_name")
+// CHECK-NEXT: public func namedLegacyCDecl
diff --git a/test/ModuleInterface/clang-args-transitive-availability.swift b/test/ModuleInterface/clang-args-transitive-availability.swift
index 267f707cce437..7e773f58805a2 100644
--- a/test/ModuleInterface/clang-args-transitive-availability.swift
+++ b/test/ModuleInterface/clang-args-transitive-availability.swift
@@ -16,6 +16,9 @@ import ImportsMacroSpecificClangModule
 // CHECK-DAG:          "swift": "Swift"
 // CHECK-DAG:          "swift": "SwiftOnoneSupport"
 
+// Additional occurence in source-imported dependencies field
+//CHECK:      "swift": "ImportsMacroSpecificClangModule"
+
 //CHECK:      "swift": "ImportsMacroSpecificClangModule"
 //CHECK-NEXT:    },
 //CHECK-NEXT:    {
@@ -48,7 +51,7 @@ import ImportsMacroSpecificClangModule
 // CHECK-NEXT:      "sourceFiles": [
 // CHECK-DAG:        "{{.*}}OnlyWithMacro.h"
 // CHECK-DAG:        "{{.*}}module.modulemap"
-// CHECK-NEXT:      ],
+// CHECK:           ],
 // CHECK-NEXT:      "directDependencies": [
 // CHECK-NEXT:      ],
 // CHECK-NEXT:      "linkLibraries": [
diff --git a/test/ModuleInterface/clang-session-transitive.swift b/test/ModuleInterface/clang-session-transitive.swift
index a1f2f27640aea..7f37e7e8759eb 100644
--- a/test/ModuleInterface/clang-session-transitive.swift
+++ b/test/ModuleInterface/clang-session-transitive.swift
@@ -16,6 +16,9 @@ import TestModule
  // CHECK-DAG:          "swift": "Swift"
  // CHECK-DAG:          "swift": "SwiftOnoneSupport"
 
+// Additional occurence in source-imported dependencies field
+ // CHECK:      "swift": "TestModule"
+
  // CHECK:      "swift": "TestModule"
  // CHECK-NEXT:    },
  // CHECK-NEXT:    {
diff --git a/test/ModuleInterface/conformances.swift b/test/ModuleInterface/conformances.swift
index 4d3691452c0ca..e584eabd9f189 100644
--- a/test/ModuleInterface/conformances.swift
+++ b/test/ModuleInterface/conformances.swift
@@ -230,11 +230,11 @@ extension PrivateProtoConformer : PrivateProto {
 // NEGATIVE-NOT: extension {{(Swift.)?}}Bool{{.+}}Equatable
 
 
-@available(macOS 10.97, iOS 22, *)
+@available(macOS 10.97, iOS 13.22, *)
 @available(tvOS, unavailable)
 @available(swift 4.2.123)
 public struct NestedAvailabilityOuter {
-  @available(iOS 23, *)
+  @available(iOS 13.23, *)
   public struct Inner: PrivateSubProto {}
 }
 
@@ -244,7 +244,7 @@ public struct NestedAvailabilityOuter {
 // CHECK: @available(*, unavailable)
 // CHECK-NEXT: extension conformances.NonSendable : @unchecked Swift.Sendable {
 
-// CHECK-END: @available(macOS 10.97, iOS 23, *)
+// CHECK-END: @available(macOS 10.97, iOS 13.23, *)
 // CHECK-END: @available(tvOS, unavailable)
 // CHECK-END: extension conformances.NestedAvailabilityOuter.Inner : conformances.PublicBaseProto {}
 
diff --git a/test/ModuleInterface/distributed-actor.swift b/test/ModuleInterface/distributed-actor.swift
index 2edb8c2efbe15..1d8c73c73096e 100644
--- a/test/ModuleInterface/distributed-actor.swift
+++ b/test/ModuleInterface/distributed-actor.swift
@@ -73,9 +73,6 @@ public distributed actor DAG<ActorSystem> where ActorSystem: DistributedActorSys
 // CHECK: }
 }
 
-// CHECK-NOT: #if compiler(>=5.3) && $Actors
-// CHECK:     @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
-// CHECK-NEXT:extension Library.DA : Distributed.DistributedActor {}
 // CHECK-NOT: #if compiler(>=5.3) && $Actors
 // CHECK:     @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 // CHECK-NEXT:extension Library.DA : Swift.Encodable {}
@@ -83,10 +80,6 @@ public distributed actor DAG<ActorSystem> where ActorSystem: DistributedActorSys
 // CHECK:     @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 // CHECK-NEXT:extension Library.DA : Swift.Decodable {}
 
-// CHECK-NOT: #if compiler(>=5.3) && $Actors
-// CHECK: @available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
-// CHECK-NEXT: extension Library.DAG : Distributed.DistributedActor {}
-
 //--- Client.swift
 
 import Distributed
diff --git a/test/ModuleInterface/distributed_no_redundant_conformance.swift b/test/ModuleInterface/distributed_no_redundant_conformance.swift
new file mode 100644
index 0000000000000..012c23c3140bb
--- /dev/null
+++ b/test/ModuleInterface/distributed_no_redundant_conformance.swift
@@ -0,0 +1,24 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-emit-module-interface(%t/TestResilient.swiftinterface) %s -module-name TestResilient
+// RUN: %target-swift-typecheck-module-from-interface(%t/TestResilient.swiftinterface) -module-name TestResilient
+// RUN: %FileCheck %s < %t/TestResilient.swiftinterface
+
+import Distributed
+
+// Note that tat while an actor is implicitly conforming to Actor, we don't need to print this in interfaces
+// as it would cause 'redundant conformance of ... to (Distributed)Actor' issues.
+
+public actor Example {}
+
+// CHECK-NOT: extension TestResilient.Example : _Concurrency.Actor {}
+
+@available(SwiftStdlib 5.7, *)
+public distributed actor DistributedExample {
+  public typealias ActorSystem = LocalTestingDistributedActorSystem
+  distributed func example() {}
+}
+
+// CHECK: distributed public actor DistributedExample {
+
+// CHECK-NOT: extension TestResilient.DistributedExample : Distributed.DistributedActor {}
diff --git a/test/ModuleInterface/escaping_functions.swift b/test/ModuleInterface/escaping_functions.swift
new file mode 100644
index 0000000000000..5f9c72245fc0b
--- /dev/null
+++ b/test/ModuleInterface/escaping_functions.swift
@@ -0,0 +1,16 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %s -module-name Test
+// RUN: %FileCheck %s < %t.swiftinterface
+// RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -module-name Test
+
+// This test fails if we suppress the @escaping attribute recursively
+// when printing enum element parameter lists instead of only suppressing
+// it when printing the immediate type of the enum payload.
+
+public enum A {
+  case function(_: (@escaping () -> Void) -> Void)
+}
+
+// CHECK-LABEL: public enum A {
+// CHECK-NEXT:    case function((@escaping () -> Swift.Void) -> Swift.Void)
+// CHECK-NEXT:  }
diff --git a/test/ModuleInterface/execution_attr.swift b/test/ModuleInterface/execution_attr.swift
deleted file mode 100644
index d3b2e4ada0a76..0000000000000
--- a/test/ModuleInterface/execution_attr.swift
+++ /dev/null
@@ -1,66 +0,0 @@
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %s -module-name execution_attr -enable-experimental-feature ExecutionAttribute
-// RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -module-name execution_attr
-
-// RUN: %FileCheck %s --input-file %t.swiftinterface
-
-// REQUIRES: swift_feature_ExecutionAttribute
-
-public struct Test {
-  // CHECK:  #if compiler(>=5.3) && $ExecutionAttribute
-  // CHECK-NEXT:  @execution(caller) public init() async
-  // CHECK-NEXT:  #else
-  // CHECK-NEXT:  public init() async
-  // CHECK-NEXT:  #endif
-  @execution(caller)
-  public init() async {
-  }
-
-  // CHECK:  #if compiler(>=5.3) && $ExecutionAttribute
-  // CHECK-NEXT:  @execution(concurrent) public func test() async
-  // CHECK-NEXT:  #else
-  // CHECK-NEXT:  public func test() async
-  // CHECK-NEXT:  #endif
-  @execution(concurrent)
-  public func test() async {
-  }
-
-  // CHECK:  #if compiler(>=5.3) && $ExecutionAttribute
-  // CHECK-NEXT:  public func other(_: @execution(caller) () async -> Swift.Void)
-  // CHECK-NEXT:  #else
-  // CHECK-NEXT:  public func other(_: () async -> Swift.Void)
-  // CHECK-NEXT:  #endif
-  public func other(_: @execution(caller) () async -> Void) {}
-
-  // CHECK: #if compiler(>=5.3) && $ExecutionAttribute
-  // CHECK-NEXT: @execution(caller) public var testOnVar: Swift.Int {
-  // CHECK-NEXT:   get async
-  // CHECK-NEXT: }
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public var testOnVar: Swift.Int {
-  // CHECK-NEXT:   get async
-  // CHECK-NEXT: }
-  // CHECK-NEXT: #endif
-  @execution(caller)
-  public var testOnVar: Int {
-    get async {
-      42
-    }
-  }
-
-  // CHECK: #if compiler(>=5.3) && $ExecutionAttribute
-  // CHECK-NEXT: @execution(caller) public subscript(onSubscript _: Swift.Int) -> Swift.Bool {
-  // CHECK-NEXT:   get async
-  // CHECK-NEXT: }
-  // CHECK-NEXT: #else
-  // CHECK-NEXT: public subscript(onSubscript _: Swift.Int) -> Swift.Bool {
-  // CHECK-NEXT:   get async
-  // CHECK-NEXT: }
-  // CHECK-NEXT: #endif
-  @execution(caller)
-  public subscript(onSubscript _: Int) -> Bool {
-    get async {
-      false
-    }
-  }
-}
-
diff --git a/test/ModuleInterface/execution_behavior_attrs.swift b/test/ModuleInterface/execution_behavior_attrs.swift
new file mode 100644
index 0000000000000..a592110dd5f35
--- /dev/null
+++ b/test/ModuleInterface/execution_behavior_attrs.swift
@@ -0,0 +1,116 @@
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %s -module-name execution_attr
+// RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -module-name execution_attr
+
+// RUN: %FileCheck %s --input-file %t.swiftinterface
+
+// REQUIRES: concurrency
+
+public struct TestWithAttrs {
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: public func test(_: nonisolated(nonsending) @escaping () async -> Swift.Void)
+  // CHECK-NEXT: #endif
+  public func test(_: nonisolated(nonsending) @escaping () async -> Void) {}
+
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: public func withInOut(fn: nonisolated(nonsending) inout () async -> Swift.Void)
+  // CHECK-NEXT: #endif
+  public func withInOut(fn: nonisolated(nonsending) inout () async -> Void) {}
+}
+
+public struct Test {
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: nonisolated(nonsending) public init() async
+  // CHECK-NEXT: #endif
+  nonisolated(nonsending)
+  public init() async {
+  }
+
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: @concurrent public init(something: Swift.Int) async
+  // CHECK-NEXT: #endif
+  @concurrent
+  public init(something: Int) async {
+  }
+
+  // CHECK-NOT: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK: public init(noExplicit: Swift.String) async
+  // CHECK-NOT: #endif
+  public init(noExplicit: String) async {
+  }
+
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT:  @concurrent public func test() async
+  // CHECK-NEXT: #endif
+  @concurrent
+  public func test() async {
+  }
+
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: public func other(_: nonisolated(nonsending) () async -> Swift.Void)
+  // CHECK-NEXT: #endif
+  public func other(_: nonisolated(nonsending) () async -> Void) {}
+
+  // CHECK-NOT: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK: public func concurrentResult(_: () async -> Swift.Void) -> (Swift.Int) async -> Swift.Void
+  // CHECK-NOT: #endif
+  public func concurrentResult(_: () async -> Void) -> @concurrent (Int) async -> Void {}
+
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: public func nestedPositions1(_: Swift.Array<[Swift.String : nonisolated(nonsending) (Swift.Int) async -> Swift.Void]>)
+  // CHECK-NEXT: #endif
+  public func nestedPositions1(_: Array<[String: nonisolated(nonsending) (Int) async -> Void]>) {}
+
+  // CHECK-NOT: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK: public func nestedPositions2(_: Swift.Array<[Swift.String : (Swift.Int) async -> Swift.Void]>)
+  // CHECK-NOT: #endif
+  public func nestedPositions2(_: Array<[String: @concurrent (Int) async -> Void]>) {}
+
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: nonisolated(nonsending) public var testOnVar: Swift.Int {
+  // CHECK-NEXT:   get async
+  // CHECK-NEXT: }
+  // CHECK-NEXT: #endif
+  nonisolated(nonsending)
+  public var testOnVar: Int {
+    get async {
+      42
+    }
+  }
+
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: @concurrent public var testOnVarConcurrent: Swift.Int {
+  // CHECK-NEXT:   get async
+  // CHECK-NEXT: }
+  // CHECK-NEXT: #endif
+  @concurrent
+  public var testOnVarConcurrent: Int {
+    get async {
+      42
+    }
+  }
+
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: nonisolated(nonsending) public subscript(onSubscript _: Swift.Int) -> Swift.Bool {
+  // CHECK-NEXT:   get async
+  // CHECK-NEXT: }
+  // CHECK-NEXT: #endif
+  nonisolated(nonsending)
+  public subscript(onSubscript _: Int) -> Bool {
+    get async {
+      false
+    }
+  }
+
+  // CHECK: #if compiler(>=5.3) && $AsyncExecutionBehaviorAttributes
+  // CHECK-NEXT: @concurrent public subscript(concurrentOnSubscript _: Swift.Int) -> Swift.Bool {
+  // CHECK-NEXT:   get async
+  // CHECK-NEXT: }
+  // CHECK-NEXT: #endif
+  @concurrent
+  public subscript(concurrentOnSubscript _: Int) -> Bool {
+    get async {
+      false
+    }
+  }
+}
+
diff --git a/test/ModuleInterface/extensible_enums.swift b/test/ModuleInterface/extensible_enums.swift
deleted file mode 100644
index 8f3d985a32ab6..0000000000000
--- a/test/ModuleInterface/extensible_enums.swift
+++ /dev/null
@@ -1,110 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: %empty-directory(%t/src)
-// RUN: split-file %s %t/src
-
-/// Build the library
-// RUN: %target-swift-frontend -emit-module %t/src/Lib.swift \
-// RUN:   -module-name Lib \
-// RUN:   -emit-module-path %t/Lib.swiftmodule \
-// RUN:   -enable-experimental-feature ExtensibleEnums
-
-// Check that the errors are produced when using enums from module with `ExtensibleEnums` feature enabled.
-// RUN: %target-swift-frontend -typecheck %t/src/TestChecking.swift \
-// RUN:   -swift-version 5 -module-name Client -I %t \
-// RUN:   -verify
-
-// Test to make sure that if the library and client are in the same package enums are checked exhaustively
-
-/// Build the library
-// RUN: %target-swift-frontend -emit-module %t/src/Lib.swift \
-// RUN:   -module-name Lib \
-// RUN:   -package-name Test \
-// RUN:   -emit-module-path %t/Lib.swiftmodule \
-// RUN:   -enable-experimental-feature ExtensibleEnums
-
-// Different module but the same package
-// RUN: %target-swift-frontend -typecheck %t/src/TestSamePackage.swift \
-// RUN:   -swift-version 5 -module-name Client -I %t \
-// RUN:   -package-name Test \
-// RUN:   -verify
-
-// REQUIRES: swift_feature_ExtensibleEnums
-
-//--- Lib.swift
-
-public enum E {
-  case a
-}
-
-@frozen
-public enum F {
-  case a
-  case b
-}
-
-func test_same_module(e: E, f: F) {
-  switch e { // Ok
-  case .a: break 
-  }
-
-  switch f { // Ok
-  case .a: break
-  case .b: break
-  }
-}
-
-//--- TestChecking.swift
-import Lib
-
-func test(e: E, f: F) {
-  // `E` is not marked as `@frozen` which means it gets new semantics
-
-  switch e {
-  // expected-error@-1 {{switch covers known cases, but 'E' may have additional unknown values, possibly added in future versions}}
-  // expected-note@-2 {{handle unknown values using "@unknown default"}}
-  case .a: break
-  }
-
-  switch e { // Ok (no warnings)
-  case .a: break
-  @unknown default: break
-  }
-
-  // `F` is marked as `@frozen` which means regular rules apply even with `ExtensibleEnums` feature enabled.  
-
-  switch f { // Ok (no errors because `F` is `@frozen`)
-  case .a: break
-  case .b: break
-  }
-
-  switch f { // expected-error {{switch must be exhaustive}} expected-note {{dd missing case: '.b'}}
-  case .a: break
-  }
-  
-  switch f { // expected-warning {{switch must be exhaustive}} expected-note {{dd missing case: '.b'}}
-  case .a: break
-  @unknown default: break
-  }
-}
-
-//--- TestSamePackage.swift
-import Lib
-
-func test_no_default(e: E, f: F) {
-  switch e { // Ok
-  case .a: break
-  }
-
-  switch e { // expected-warning {{switch must be exhaustive}} expected-note {{dd missing case: '.a'}}
-  @unknown default: break
-  }
-
-  switch f { // expected-error {{switch must be exhaustive}} expected-note {{dd missing case: '.b'}}
-  case .a: break
-  }
-
-  switch f { // expected-warning {{switch must be exhaustive}} expected-note {{dd missing case: '.b'}}
-  case .a: break
-  @unknown default: break
-  }
-}
diff --git a/test/ModuleInterface/extension-transitive-availability.swift b/test/ModuleInterface/extension-transitive-availability.swift
index 201a74dafb6cf..dda66181d1bcd 100644
--- a/test/ModuleInterface/extension-transitive-availability.swift
+++ b/test/ModuleInterface/extension-transitive-availability.swift
@@ -17,6 +17,9 @@ func foo() {
 // CHECK-DAG:          "swift": "Swift"
 // CHECK-DAG:          "swift": "SwiftOnoneSupport"
 
+// Additional occurence in source-imported dependencies field
+// CHECK:      "swift": "ExtensionAvailable"
+
 // CHECK:      "swift": "ExtensionAvailable"
 // CHECK-NEXT:    },
 // CHECK-NEXT:    {
diff --git a/test/ModuleInterface/implicit-import.swift b/test/ModuleInterface/implicit-import.swift
index f8413cf225720..ab74a279a5b74 100644
--- a/test/ModuleInterface/implicit-import.swift
+++ b/test/ModuleInterface/implicit-import.swift
@@ -13,7 +13,7 @@
 // RUN: %target-swift-emit-module-interface(%t/DefinesExtension.swiftinterface) -I %t %t/DefinesExtension.swift -module-name DefinesExtension
 // RUN: %target-swift-typecheck-module-from-interface(%t/DefinesExtension.swiftinterface) -I %t -module-name DefinesExtension
 
-// RUN: %target-swift-emit-module-interface(%t/Client.swiftinterface) -verify -I %t %t/File2.swift %t/File1.swift -module-name Client
+// RUN: %target-swift-emit-module-interface(%t/Client.swiftinterface) -verify -verify-ignore-unrelated -I %t %t/File2.swift %t/File1.swift -module-name Client
 // RUN: %target-swift-typecheck-module-from-interface(%t/Client.swiftinterface) -I %t -module-name Client
 // RUN: %FileCheck %t/File2.swift < %t/Client.swiftinterface
 
diff --git a/test/ModuleInterface/imports-swift7.swift b/test/ModuleInterface/imports-swift7.swift
index 3b10ede862313..ddb6c4c53bbdf 100644
--- a/test/ModuleInterface/imports-swift7.swift
+++ b/test/ModuleInterface/imports-swift7.swift
@@ -5,8 +5,31 @@
 // RUN: %target-swift-frontend -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -emit-module -o %t/nonResilient.swiftmodule %t/empty.swift
 // RUN: %target-swift-frontend -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -emit-module -o %t/resilient.swiftmodule %t/empty.swift -enable-library-evolution
 
-/// Check errors.
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/clientWithError.swift -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -I %t -verify -enable-upcoming-feature InternalImportsByDefault
+/// Warning vs error on public import of a non-LE module from LE.
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) \
+// RUN:     %t/clientWithError.swift -I %t -verify \
+// RUN:     -disable-implicit-concurrency-module-import \
+// RUN:     -disable-implicit-string-processing-module-import \
+// RUN:     -enable-upcoming-feature InternalImportsByDefault \
+// RUN:     -verify-additional-prefix library-level-private-
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) \
+// RUN:     %t/clientWithError.swift -I %t -verify \
+// RUN:     -disable-implicit-concurrency-module-import \
+// RUN:     -disable-implicit-string-processing-module-import \
+// RUN:     -enable-upcoming-feature InternalImportsByDefault \
+// RUN:     -verify-additional-prefix library-level-private- -library-level ipi
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) \
+// RUN:     %t/clientWithError.swift -I %t -verify \
+// RUN:     -disable-implicit-concurrency-module-import \
+// RUN:     -disable-implicit-string-processing-module-import \
+// RUN:     -enable-upcoming-feature InternalImportsByDefault \
+// RUN:     -verify-additional-prefix library-level-public- -library-level spi
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) \
+// RUN:     %t/clientWithError.swift -I %t -verify \
+// RUN:     -disable-implicit-concurrency-module-import \
+// RUN:     -disable-implicit-string-processing-module-import \
+// RUN:     -enable-upcoming-feature InternalImportsByDefault \
+// RUN:     -verify-additional-prefix library-level-public- -library-level api
 
 /// Check Swift 7 imports printed in swiftinterface from 2 source files.
 // RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/main.swift %t/main-other.swift -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -I %S/Inputs/imports-clang-modules/ -I %t -verify -enable-upcoming-feature InternalImportsByDefault
@@ -38,8 +61,11 @@ public import D // expected-warning {{public import of 'D' was not used in publi
 public import NotSoSecret // expected-warning {{'NotSoSecret' inconsistently imported as implementation-only}}
 // expected-warning @-1 {{public import of 'NotSoSecret' was not used in public declarations or inlinable code}}
 @_implementationOnly import NotSoSecret2 // expected-note {{imported as implementation-only here}}
+
 //--- clientWithError.swift
-@_exported public import nonResilient // expected-error {{module 'nonResilient' was not compiled with library evolution support; using it means binary compatibility for 'clientWithError' can't be guaranteed}}
+@_exported public import nonResilient
+// expected-library-level-public-error @-1 {{module 'nonResilient' was not compiled with library evolution support; using it means binary compatibility for 'clientWithError' can't be guaranteed}}
+// expected-library-level-private-warning @-2 {{module 'nonResilient' was not compiled with library evolution support; using it means binary compatibility for 'clientWithError' can't be guaranteed}}
 
 // CHECK-7-NOT: import
 // CHECK-7: {{^}}public import A{{$}}
diff --git a/test/ModuleInterface/inheritActorContext_attr.swift b/test/ModuleInterface/inheritActorContext_attr.swift
new file mode 100644
index 0000000000000..6074bfccbc830
--- /dev/null
+++ b/test/ModuleInterface/inheritActorContext_attr.swift
@@ -0,0 +1,39 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-emit-module-interface(%t/Library.swiftinterface) %s -module-name Library
+// RUN: %target-swift-typecheck-module-from-interface(%t/Library.swiftinterface) -module-name Library
+// RUN: %FileCheck %s < %t/Library.swiftinterface
+
+// CHECK-NOT: #if compiler(>=5.3) && $AlwaysInheritActorContext
+// CHECK: public func globalTest(@_inheritActorContext _: @Sendable () async -> Swift.Void)
+// CHECK-NOT: #endif
+public func globalTest(@_inheritActorContext _: @Sendable () async -> Void) {}
+
+// CHECK: #if compiler(>=5.3) && $AlwaysInheritActorContext
+// CHECK-NEXT: public func globalTestAlways(@_inheritActorContext(always) _: @Sendable () async -> Swift.Void)
+// CHECK-NEXT: #endif
+public func globalTestAlways(@_inheritActorContext(always) _: @Sendable () async -> Void) {}
+
+public struct Test {
+  // CHECK-NOT: #if compiler(>=5.3) && $AlwaysInheritActorContext
+  // CHECK: public init(@_inheritActorContext x: @Sendable () async -> Swift.Int)
+  // CHECK-NOT: #endif
+  public init(@_inheritActorContext x: @Sendable () async -> Int) {}
+
+  // CHECK: #if compiler(>=5.3) && $AlwaysInheritActorContext
+  // CHECK-NEXT: public init(@_inheritActorContext(always) y: sending () async -> Swift.Void)
+  // CHECK-NEXT: #endif
+  public init(@_inheritActorContext(always) y: sending () async -> Void) {}
+
+  // CHECK-NOT: #if compiler(>=5.3) && $AlwaysInheritActorContext
+  // CHECK: public subscript(@_inheritActorContext _: @Sendable () async -> Swift.Void) -> Swift.Bool {
+  // CHECK-NEXT:   get
+  // CHECK-NEXT: }
+  // CHECK-NOT: #endif
+  public subscript(@_inheritActorContext _: @Sendable () async -> Void) -> Bool { false }
+
+  // CHECK: #if compiler(>=5.3) && $AlwaysInheritActorContext
+  // CHECK-NEXT: public subscript(@_inheritActorContext(always) _: @Sendable (Swift.Int) async -> Swift.Void) -> Swift.Bool {
+  // CHECK-NEXT:   get
+  // CHECK-NEXT: }
+  public subscript(@_inheritActorContext(always) _: @Sendable (Int) async -> Void) -> Bool { false }
+}
diff --git a/test/ModuleInterface/init_accessors.swift b/test/ModuleInterface/init_accessors.swift
index 4680361930b69..88d6f3bca3a7c 100644
--- a/test/ModuleInterface/init_accessors.swift
+++ b/test/ModuleInterface/init_accessors.swift
@@ -28,7 +28,7 @@ public struct Inlinable {
 // CHECK-NEXT:    @usableFromInline
 // CHECK-NEXT:    @storageRestrictions(initializes: _x) init
 // CHECK-NEXT:    get
-// CHECK-NEXT  }
+// CHECK-NEXT:  }
 
   public var x: Int {
     @usableFromInline
@@ -75,7 +75,7 @@ public struct Transparent {
 // CHECK-NEXT:     self._x = newValue
 // CHECK-NEXT:   }
 // CHECK-NEXT:   get
-// CHECK-NEXT  }
+// CHECK-NEXT:  }
 
   public var x: Int {
     @_alwaysEmitIntoClient
diff --git a/test/ModuleInterface/inlinable-function.swift b/test/ModuleInterface/inlinable-function.swift
index 6df0ae4122370..81d47825ee1eb 100644
--- a/test/ModuleInterface/inlinable-function.swift
+++ b/test/ModuleInterface/inlinable-function.swift
@@ -99,7 +99,7 @@ public struct Foo: Hashable {
     // FROMSOURCE:     print("I am set to \(newValue)")
     // FROMSOURCE-NOT: #else
     // FROMSOURCE-NOT: print("I should not appear")
-    // FROMSOURCE-NOT  #endif
+    // FROMSOURCE-NOT:  #endif
     // FROMSOURCE: }
     set {
       #if true
diff --git a/test/ModuleInterface/invalid-opaque-result-types.swift b/test/ModuleInterface/invalid-opaque-result-types.swift
deleted file mode 100644
index fffc5dc985ade..0000000000000
--- a/test/ModuleInterface/invalid-opaque-result-types.swift
+++ /dev/null
@@ -1,23 +0,0 @@
-// Test that we emit a diagnostic (and don't crash) when we cannot resolve
-// an opaque result type reference.
-//
-// First, emit an empty module interface:
-//
-// RUN: %empty-directory(%t)
-// RUN: echo "" | %target-swift-frontend -typecheck -emit-module-interface-path %t/InvalidOpaqueResultType.swiftinterface -enable-library-evolution -swift-version 5 -module-name InvalidOpaqueResultType -
-//
-// Then, blit some invalid opaque result types into the interface
-//
-// Test that we reject broken type parameters
-// RUN: echo "public typealias SomeGenericBalderdash = @_opaqueReturnTypeOf(\"$somesuchnonsense\", 0) __<InvalidParameter>" >> %t/InvalidOpaqueResultType.swiftinterface
-// Test that we reject types we cannot demangle
-// RUN: echo "public typealias SomesuchNonsense = @_opaqueReturnTypeOf(\"$somesuchnonsense\", 0) __" >> %t/InvalidOpaqueResultType.swiftinterface
-//
-// The stage is set:
-//
-// RUN: not %target-swift-frontend -typecheck %s -I %t 2>&1 | %FileCheck %s
-
-// CHECK: cannot find type 'InvalidParameter' in scope
-// CHECK: unable to resolve type for _opaqueReturnTypeOf attribute
-// CHECK: failed to build module 'InvalidOpaqueResultType' for importation
-import InvalidOpaqueResultType
diff --git a/test/ModuleInterface/invalid-opaque-result-types.swiftinterface b/test/ModuleInterface/invalid-opaque-result-types.swiftinterface
new file mode 100644
index 0000000000000..589dfaaaecab6
--- /dev/null
+++ b/test/ModuleInterface/invalid-opaque-result-types.swiftinterface
@@ -0,0 +1,29 @@
+// Test that we emit a diagnostic (and don't crash) when we cannot resolve
+// an opaque result type reference.
+//
+// RUN: %target-typecheck-verify-swift -module-name OpaqueTypes
+//
+
+public struct G<T> {
+  public func f() -> some Any
+}
+
+// Type doesn't demangle
+public typealias Bad1 = @_opaqueReturnTypeOf("nonsense", 0) __
+// expected-error@-1 {{unable to resolve type for _opaqueReturnTypeOf attribute}}
+
+// Type demangles but doesn't name an opaque return type
+public typealias Bad2 = @_opaqueReturnTypeOf("$sSi", 0) __
+// expected-error@-1 {{unable to resolve type for _opaqueReturnTypeOf attribute}}
+
+// Bad index
+public typealias Bad3 = @_opaqueReturnTypeOf("$s11OpaqueTypes1GV1fQryF", 5) __<Int>
+// expected-error@-1 {{unable to resolve type for _opaqueReturnTypeOf attribute}}
+
+// Bad generic argument
+public typealias Bad4 = @_opaqueReturnTypeOf("$s11OpaqueTypes1GV1fQryF", 0) __<InvalidType>
+// expected-error@-1 {{cannot find type 'InvalidType' in scope}}
+
+// Missing generic argument
+public typealias Bad5 = @_opaqueReturnTypeOf("$s11OpaqueTypes1GV1fQryF", 0) __
+// expected-error@-1 {{unable to resolve type for _opaqueReturnTypeOf attribute}}
diff --git a/test/ModuleInterface/isolated-deinit-compatibility.swift b/test/ModuleInterface/isolated-deinit-compatibility.swift
deleted file mode 100644
index 81975fa794243..0000000000000
--- a/test/ModuleInterface/isolated-deinit-compatibility.swift
+++ /dev/null
@@ -1,153 +0,0 @@
-// RUN: %target-swift-frontend -target %target-future-triple -emit-silgen -verify %s
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) -DEMIT_IFACE %s -target %target-future-triple -module-name IsolatedDeinitCompatibility
-// RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -target %target-future-triple -module-name IsolatedDeinitCompatibility
-// RUN: %FileCheck %s < %t.swiftinterface
-
-
-// MARK: Sync deinit in class
-
-// CHECK-NOT: #
-// CHECK: open class SyncClassDefaultOpen {
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}deinit
-// CHECK-NOT: #
-// CHECK: }
-open class SyncClassDefaultOpen {
-    deinit {}
-}
-
-// CHECK-NOT: #
-// CHECK: public class SyncClassDefaultPublic {
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}deinit
-// CHECK-NOT: #
-// CHECK: }
-public class SyncClassDefaultPublic {
-    deinit {}
-}
-
-// CHECK: #if {{.*}}$IsolatedDeinit
-// CHECK-NOT: #
-// CHECK: open class SyncClassGlobalActorOpen {
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}@_Concurrency.MainActor deinit
-// CHECK-NOT: #
-// CHECK: }
-// CHECK: #endif
-open class SyncClassGlobalActorOpen {
-    @MainActor deinit {}
-}
-
-// CHECK-NOT: #
-// CHECK: public class SyncClassGlobalActorPublic {
-// CHECK-NOT: #
-// CHECK: #if {{.*}}$IsolatedDeinit
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}@_Concurrency.MainActor deinit
-// CHECK: }
-public class SyncClassGlobalActorPublic {
-    @MainActor deinit {}
-}
-
-// CHECK: #if {{.*}}$IsolatedDeinit
-// CHECK-NOT: #
-// CHECK: @_Concurrency.MainActor open class SyncClassIsolatedOpen {
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}isolated deinit
-// CHECK-NOT: #
-// CHECK: }
-// CHECK: #endif
-@MainActor
-open class SyncClassIsolatedOpen {
-    isolated deinit {}
-}
-
-// CHECK-NOT: #
-// CHECK: @_Concurrency.MainActor public class SyncClassIsolatedPublic {
-// CHECK-NOT: #
-// CHECK: #if {{.*}}$IsolatedDeinit
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}isolated deinit
-// CHECK: }
-@MainActor
-public class SyncClassIsolatedPublic {
-    isolated deinit {}
-}
-
-// CHECK: #if {{.*}}$IsolatedDeinit
-// CHECK-NOT: #
-// CHECK: @_Concurrency.MainActor open class SyncClassNonisolatedOpen {
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}nonisolated deinit
-// CHECK-NOT: #
-// CHECK: }
-// CHECK: #endif
-@MainActor
-open class SyncClassNonisolatedOpen {
-    nonisolated deinit {}
-}
-
-// CHECK-NOT: #
-// CHECK: @_Concurrency.MainActor public class SyncClassNonisolatedPublic {
-// CHECK-NOT: #
-// CHECK: #if {{.*}}$IsolatedDeinit
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}nonisolated deinit
-// CHECK: }
-@MainActor
-public class SyncClassNonisolatedPublic {
-    nonisolated deinit {}
-}
-
-// MARK: Sync deinit in actor
-
-// CHECK-NOT: #
-// CHECK: public actor SyncActorDefaultPublic {
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}deinit
-// CHECK-NOT: #
-// CHECK: }
-public actor SyncActorDefaultPublic {
-    deinit {}
-}
-
-// CHECK-NOT: #
-// CHECK: public actor SyncActorGlobalActorPublic {
-// CHECK-NOT: #
-// CHECK: #if {{.*}}$IsolatedDeinit
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}@_Concurrency.MainActor deinit
-// CHECK: }
-public actor SyncActorGlobalActorPublic {
-    @MainActor deinit {}
-}
-
-// CHECK-NOT: #
-// CHECK: public actor SyncActorIsolatedPublic {
-// CHECK-NOT: #
-// CHECK: #if {{.*}}$IsolatedDeinit
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}isolated deinit
-// CHECK: }
-public actor SyncActorIsolatedPublic {
-    isolated deinit {}
-}
-
-// CHECK-NOT: #
-// CHECK: public actor SyncActorNonisolatedPublic {
-// CHECK-NOT: #
-// CHECK: #if {{.*}}$IsolatedDeinit
-// CHECK-NOT: #
-// CHECK: {{(@objc )?}}nonisolated deinit
-// CHECK: }
-public actor SyncActorNonisolatedPublic {
-    nonisolated deinit {}
-}
-
-// MARK: - Open actor
-
-// Check that open actors are not allowed
-// If they become allowed in the future, extra test cases need to be added to this test
-#if !EMIT_IFACE
-open actor OpenActor {} // expected-error {{only classes and overridable class members can be declared 'open'; use 'public'}}
-#endif
diff --git a/test/ModuleInterface/isolated-deinit.swift b/test/ModuleInterface/isolated-deinit.swift
new file mode 100644
index 0000000000000..85eb997aa4566
--- /dev/null
+++ b/test/ModuleInterface/isolated-deinit.swift
@@ -0,0 +1,136 @@
+// RUN: %target-swift-frontend -target %target-future-triple -emit-silgen -verify %s
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) -DEMIT_IFACE %s -target %target-future-triple -module-name IsolatedDeinitCompatibility
+// RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -target %target-future-triple -module-name IsolatedDeinitCompatibility
+// RUN: %FileCheck %s < %t.swiftinterface
+
+
+// MARK: Sync deinit in class
+
+// CHECK-NOT: #
+// CHECK: open class SyncClassDefaultOpen {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}deinit
+// CHECK-NOT: #
+// CHECK: }
+open class SyncClassDefaultOpen {
+    deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: public class SyncClassDefaultPublic {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}deinit
+// CHECK-NOT: #
+// CHECK: }
+public class SyncClassDefaultPublic {
+    deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: open class SyncClassGlobalActorOpen {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}@_Concurrency.MainActor deinit
+// CHECK-NOT: #
+// CHECK: }
+open class SyncClassGlobalActorOpen {
+    @MainActor deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: public class SyncClassGlobalActorPublic {
+// CHECK-NOT: #
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}@_Concurrency.MainActor deinit
+// CHECK: }
+public class SyncClassGlobalActorPublic {
+    @MainActor deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: @_Concurrency.MainActor open class SyncClassIsolatedOpen {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}isolated deinit
+// CHECK-NOT: #
+// CHECK: }
+@MainActor
+open class SyncClassIsolatedOpen {
+    isolated deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: @_Concurrency.MainActor public class SyncClassIsolatedPublic {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}isolated deinit
+// CHECK: }
+@MainActor
+public class SyncClassIsolatedPublic {
+    isolated deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: @_Concurrency.MainActor open class SyncClassNonisolatedOpen {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}nonisolated deinit
+// CHECK-NOT: #
+// CHECK: }
+@MainActor
+open class SyncClassNonisolatedOpen {
+    nonisolated deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: @_Concurrency.MainActor public class SyncClassNonisolatedPublic {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}nonisolated deinit
+// CHECK: }
+@MainActor
+public class SyncClassNonisolatedPublic {
+    nonisolated deinit {}
+}
+
+// MARK: Sync deinit in actor
+
+// CHECK-NOT: #
+// CHECK: public actor SyncActorDefaultPublic {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}deinit
+// CHECK-NOT: #
+// CHECK: }
+public actor SyncActorDefaultPublic {
+    deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: public actor SyncActorGlobalActorPublic {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}@_Concurrency.MainActor deinit
+// CHECK: }
+public actor SyncActorGlobalActorPublic {
+    @MainActor deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: public actor SyncActorIsolatedPublic {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}isolated deinit
+// CHECK: }
+public actor SyncActorIsolatedPublic {
+    isolated deinit {}
+}
+
+// CHECK-NOT: #
+// CHECK: public actor SyncActorNonisolatedPublic {
+// CHECK-NOT: #
+// CHECK: {{(@objc )?}}nonisolated deinit
+// CHECK: }
+public actor SyncActorNonisolatedPublic {
+    nonisolated deinit {}
+}
+
+// MARK: - Open actor
+
+// Check that open actors are not allowed
+// If they become allowed in the future, extra test cases need to be added to this test
+#if !EMIT_IFACE
+open actor OpenActor {} // expected-error {{only classes and overridable class members can be declared 'open'; use 'public'}}
+#endif
diff --git a/test/ModuleInterface/isolated_any.swift b/test/ModuleInterface/isolated_any.swift
new file mode 100644
index 0000000000000..387518d7cd04d
--- /dev/null
+++ b/test/ModuleInterface/isolated_any.swift
@@ -0,0 +1,15 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -module-name isolated_any -emit-module -o %t/isolated_any.swiftmodule -emit-module-interface-path - %s | %FileCheck %s
+// RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -module-name isolated_any -emit-module -o %t/isolated_any.swiftmodule -emit-module-interface-path - %s | %FileCheck %s
+
+// CHECK: {{^}}public func test1(fn: @isolated(any) @Sendable () -> ())
+public func test1(fn: @isolated(any) @Sendable () -> ()) {}
+
+// CHECK-NEXT: {{^}}public func test2(fn: @isolated(any) @Sendable () -> ())
+@_allowFeatureSuppression(XXX)
+public func test2(fn: @isolated(any) @Sendable () -> ()) {}
+
+// CHECK-NEXT: {{^}}public func test3(fn: @isolated(any) @Sendable () -> ())
+@_allowFeatureSuppression(IsolatedAny)
+public func test3(fn: @isolated(any) @Sendable () -> ()) {}
diff --git a/test/ModuleInterface/isolated_any_suppression.swift b/test/ModuleInterface/isolated_any_suppression.swift
deleted file mode 100644
index 8322e83167b6d..0000000000000
--- a/test/ModuleInterface/isolated_any_suppression.swift
+++ /dev/null
@@ -1,23 +0,0 @@
-// RUN: %empty-directory(%t)
-
-// RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -module-name isolated_any -emit-module -o %t/isolated_any.swiftmodule -emit-module-interface-path - %s | %FileCheck %s
-// RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -module-name isolated_any -emit-module -o %t/isolated_any.swiftmodule -emit-module-interface-path - %s | %FileCheck %s
-
-// CHECK:      #if compiler(>=5.3) && $IsolatedAny
-// CHECK-NEXT: {{^}}public func test1(fn: @isolated(any) @Sendable () -> ())
-// CHECK-NEXT: #endif
-public func test1(fn: @isolated(any) @Sendable () -> ()) {}
-
-// CHECK-NEXT: #if compiler(>=5.3) && $IsolatedAny
-// CHECK-NEXT: {{^}}public func test2(fn: @isolated(any) @Sendable () -> ())
-// CHECK-NEXT: #endif
-@_allowFeatureSuppression(XXX)
-public func test2(fn: @isolated(any) @Sendable () -> ()) {}
-
-// CHECK-NEXT: #if compiler(>=5.3) && $IsolatedAny
-// CHECK-NEXT: {{^}}public func test3(fn: @isolated(any) @Sendable () -> ())
-// CHECK-NEXT: #else
-// CHECK-NEXT: {{^}}public func test3(fn: @Sendable () -> ())
-// CHECK-NEXT: #endif
-@_allowFeatureSuppression(IsolatedAny)
-public func test3(fn: @isolated(any) @Sendable () -> ()) {}
diff --git a/test/ModuleInterface/isolated_conformance.swift b/test/ModuleInterface/isolated_conformance.swift
index 23d93fcdd4572..9ed21b8b67eca 100644
--- a/test/ModuleInterface/isolated_conformance.swift
+++ b/test/ModuleInterface/isolated_conformance.swift
@@ -1,6 +1,5 @@
-// RUN: %target-swift-frontend -typecheck -swift-version 6 -enable-library-evolution -module-name isolated_conformance -enable-experimental-feature IsolatedConformances -emit-module-interface-path - %s | %FileCheck %s
+// RUN: %target-swift-frontend -typecheck -swift-version 6 -enable-library-evolution -module-name isolated_conformance -emit-module-interface-path - %s | %FileCheck %s
 
-// REQUIRES: swift_feature_IsolatedConformances
 // REQUIRES: concurrency
 
 public protocol MyProtocol {
diff --git a/test/ModuleInterface/language_mode.swift b/test/ModuleInterface/language_mode.swift
new file mode 100644
index 0000000000000..4522c5fdd38ed
--- /dev/null
+++ b/test/ModuleInterface/language_mode.swift
@@ -0,0 +1,27 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %swift_frontend_plain -target %target-swift-5.1-abi-triple %s \
+// RUN:   -enable-library-evolution -module-name Test \
+// RUN:   -emit-module-interface-path %t.swiftinterface \
+// RUN:   -emit-module -o /dev/null 2>&1 | %FileCheck %s
+
+// CHECK: <unknown>:0: warning: emitting module interface files requires '-language-mode'
+
+// RUN: %swift_frontend_plain -target %target-swift-5.1-abi-triple %s \
+// RUN:   -enable-library-evolution -module-name Test \
+// RUN:   -emit-module-interface-path %t.swiftinterface \
+// RUN:   -emit-module -o /dev/null -language-mode 5
+
+// RUN: %FileCheck %s --check-prefix CHECK-SWIFTINTERFACE < %t.swiftinterface
+
+// RUN: %swift_frontend_plain -target %target-swift-5.1-abi-triple %s \
+// RUN:   -enable-library-evolution -module-name Test \
+// RUN:   -emit-module-interface-path %t.swiftinterface \
+// RUN:   -emit-module -o /dev/null -swift-version 5
+
+// RUN: %FileCheck %s --check-prefix CHECK-SWIFTINTERFACE < %t.swiftinterface
+
+// CHECK-SWIFTINTERFACE: swift-module-flags:
+// CHECK-SWIFTINTERFACE-SAME: -enable-library-evolution
+// CHECK-SWIFTINTERFACE-SAME: -module-name Test
+// CHECK-SWIFTINTERFACE-SAME: {{-swift-version|-language-mode}} 5
diff --git a/test/ModuleInterface/layout_pre_specialization.swift b/test/ModuleInterface/layout_pre_specialization.swift
index 9948b28ea3963..43805536de992 100644
--- a/test/ModuleInterface/layout_pre_specialization.swift
+++ b/test/ModuleInterface/layout_pre_specialization.swift
@@ -1,12 +1,10 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-emit-module-interface(%t/LayoutPrespec.swiftinterface) %s -enable-experimental-feature LayoutPrespecialization -module-name LayoutPrespec -disable-availability-checking
+// RUN: %target-swift-emit-module-interface(%t/LayoutPrespec.swiftinterface) %s -module-name LayoutPrespec -disable-availability-checking
+// RUN: %target-swift-typecheck-module-from-interface(%t/LayoutPrespec.swiftinterface) -module-name LayoutPrespec -disable-availability-checking
 // RUN: %target-swift-typecheck-module-from-interface(%t/LayoutPrespec.swiftinterface) -module-name LayoutPrespec -disable-availability-checking
-// RUN: %target-swift-typecheck-module-from-interface(%t/LayoutPrespec.swiftinterface) -module-name LayoutPrespec -enable-experimental-feature LayoutPrespecialization -disable-availability-checking
 // RUN: %FileCheck %s < %t/LayoutPrespec.swiftinterface
 
-// REQUIRES: swift_feature_LayoutPrespecialization
-
 // CHECK: @_specialize(exported: true, kind: full, where @_noMetadata A : _Class)
 // CHECK-NEXT: public func test<A>(a: A) -> A
 @_specialize(exported: true, where @_noMetadata A : _Class)
diff --git a/test/ModuleInterface/lazy-typecheck.swift b/test/ModuleInterface/lazy-typecheck.swift
index a5ae7b839b5e9..ae6598b663708 100644
--- a/test/ModuleInterface/lazy-typecheck.swift
+++ b/test/ModuleInterface/lazy-typecheck.swift
@@ -7,24 +7,24 @@
 // (1) Generate a baseline .swiftinterface and build a client against it.
 // RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -typecheck -emit-module-interface-path %t/baseline/lazy_typecheck.swiftinterface -enable-library-evolution -parse-as-library -package-name Package -DFLAG
 // RUN: rm -rf %t/baseline/*.swiftmodule
-// RUN: %target-swift-frontend -package-name ClientPackage -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -I %t/baseline/
+// RUN: %target-swift-frontend -package-name ClientPackage -typecheck -verify -verify-ignore-unrelated %S/../Inputs/lazy_typecheck_client.swift -I %t/baseline/
 
 // (2) Generate a .swiftinterface with -experimental-lazy-typecheck and build the client against it.
 //     The .swiftinterface should be identical to the baseline and avoid triggering typechecking
 //     for any "NoTypecheck" decls.
 // RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -typecheck -emit-module-interface-path %t/lazy/lazy_typecheck.swiftinterface -enable-library-evolution -parse-as-library -package-name Package -DFLAG -debug-forbid-typecheck-prefix NoTypecheck -experimental-lazy-typecheck
 // RUN: rm -rf %t/lazy/*.swiftmodule
-// RUN: %target-swift-frontend -package-name ClientPackage -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -I %t/lazy
+// RUN: %target-swift-frontend -package-name ClientPackage -typecheck -verify -verify-ignore-unrelated %S/../Inputs/lazy_typecheck_client.swift -I %t/lazy
 // RUN: diff -u %t/baseline/lazy_typecheck.swiftinterface %t/lazy/lazy_typecheck.swiftinterface
 
 // (3) Same as (2), but with -experimental-skip-all-function-bodies added.
 // RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -typecheck -emit-module-interface-path %t/lazy-skip-all/lazy_typecheck.swiftinterface -enable-library-evolution -parse-as-library -package-name Package -DFLAG -debug-forbid-typecheck-prefix NoTypecheck -experimental-lazy-typecheck -experimental-skip-non-exportable-decls -experimental-skip-all-function-bodies
 // RUN: rm -rf %t/lazy-skip-all/*.swiftmodule
-// RUN: %target-swift-frontend -package-name ClientPackage -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -I %t/lazy-skip-all
+// RUN: %target-swift-frontend -package-name ClientPackage -typecheck -verify -verify-ignore-unrelated %S/../Inputs/lazy_typecheck_client.swift -I %t/lazy-skip-all
 // RUN: diff -u %t/baseline/lazy_typecheck.swiftinterface %t/lazy-skip-all/lazy_typecheck.swiftinterface
 
 // (4) Same as (2), but with -experimental-skip-non-inlinable-function-bodies added.
 // RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -typecheck -emit-module-interface-path %t/lazy-skip-non-inlinable/lazy_typecheck.swiftinterface -enable-library-evolution -parse-as-library -package-name Package -DFLAG -debug-forbid-typecheck-prefix NoTypecheck -experimental-lazy-typecheck -experimental-skip-non-inlinable-function-bodies
 // RUN: rm -rf %t/lazy-skip-non-inlinable/*.swiftmodule
-// RUN: %target-swift-frontend -package-name ClientPackage -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -I %t/lazy-skip-non-inlinable
+// RUN: %target-swift-frontend -package-name ClientPackage -typecheck -verify -verify-ignore-unrelated %S/../Inputs/lazy_typecheck_client.swift -I %t/lazy-skip-non-inlinable
 // RUN: diff -u %t/baseline/lazy_typecheck.swiftinterface %t/lazy-skip-non-inlinable/lazy_typecheck.swiftinterface
diff --git a/test/ModuleInterface/lifetime_dependence_test.swift b/test/ModuleInterface/lifetime_dependence_test.swift
index b705ee4cd4480..6b7230419387b 100644
--- a/test/ModuleInterface/lifetime_dependence_test.swift
+++ b/test/ModuleInterface/lifetime_dependence_test.swift
@@ -2,6 +2,7 @@
 
 // RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -emit-module \
 // RUN:     -enable-experimental-feature LifetimeDependence \
+// RUN:     -suppress-warnings \
 // RUN:     -o %t/lifetime_dependence.swiftmodule \
 // RUN:     -emit-module-interface-path %t/lifetime_dependence.swiftinterface \
 // RUN:     %S/Inputs/lifetime_dependence.swift
@@ -39,5 +40,15 @@ import lifetime_dependence
 // Check that an implicitly dependent variable accessor is guarded by LifetimeDependence.
 //
 // CHECK: extension lifetime_dependence.Container {
-// CHECK-NEXT: #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+// CHECK-NEXT: #if compiler(>=5.3) && $LifetimeDependence
 // CHECK-NEXT:   public var storage: lifetime_dependence.BufferView {
+
+// CHECK-LABEL: extension Swift.UnsafeMutableBufferPointer where Element : ~Copyable {
+// CHECK:   #if compiler(>=5.3) && $LifetimeDependence
+// CHECK:   public var span: Swift.Span<Element> {
+// CHECK:     @lifetime(borrow self)
+// CHECK:     @_alwaysEmitIntoClient get {
+// CHECK:   #if compiler(>=5.3) && $NonescapableAccessorOnTrivial && $LifetimeDependence
+// CHECK:   public var mutableSpan: Swift.MutableSpan<Element> {
+// CHECK:     @lifetime(borrow self)
+// CHECK:     @_alwaysEmitIntoClient get {
diff --git a/test/ModuleInterface/lifetime_underscored_dependence_test.swift b/test/ModuleInterface/lifetime_underscored_dependence_test.swift
new file mode 100644
index 0000000000000..5ebbab3c2a567
--- /dev/null
+++ b/test/ModuleInterface/lifetime_underscored_dependence_test.swift
@@ -0,0 +1,112 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -emit-module \
+// RUN:     -enable-experimental-feature Lifetimes \
+// RUN:     -enable-experimental-feature Lifetimes \
+// RUN:     -o %t/lifetime_underscored_dependence.swiftmodule \
+// RUN:     -emit-module-interface-path %t/lifetime_underscored_dependence.swiftinterface \
+// RUN:     %S/Inputs/lifetime_underscored_dependence.swift
+
+// Check the interfaces
+
+// RUN: %FileCheck %s < %t/lifetime_underscored_dependence.swiftinterface
+
+// See if we can compile a module through just the interface and typecheck using it.
+
+// RUN: %target-swift-frontend -compile-module-from-interface \
+// RUN:    -enable-experimental-feature Lifetimes \
+// RUN:    %t/lifetime_underscored_dependence.swiftinterface -o %t/lifetime_underscored_dependence.swiftmodule
+
+// RUN: %target-swift-frontend -typecheck -I %t %s \
+// RUN:    -enable-experimental-feature Lifetimes
+
+// REQUIRES: swift_feature_Lifetimes
+
+import lifetime_underscored_dependence
+// CHECK:  #if compiler(>=5.3) && $Lifetimes
+// CHECK:  @_lifetime(borrow a)
+// CHECK:  @inlinable internal init(_ ptr: Swift.UnsafeRawBufferPointer, _ a: borrowing Swift.Array<Swift.Int>) {
+// CHECK:    let bv = BufferView(ptr, a.count)
+// CHECK:    self = _overrideLifetime(bv, borrowing: a)
+// CHECK:  }
+// CHECK:  #else
+// CHECK:  @lifetime(borrow a)
+// CHECK:  @inlinable internal init(_ ptr: Swift.UnsafeRawBufferPointer, _ a: borrowing Swift.Array<Swift.Int>) {
+// CHECK:    let bv = BufferView(ptr, a.count)
+// CHECK:    self = _overrideLifetime(bv, borrowing: a)
+// CHECK:  }
+// CHECK:  #endif
+
+// CHECK:  #if compiler(>=5.3) && $Lifetimes
+// CHECK:  @_lifetime(copy a)
+// CHECK:  @inlinable internal init(_ ptr: Swift.UnsafeRawBufferPointer, _ a: consuming lifetime_underscored_dependence.AnotherView) {
+// CHECK:    let bv = BufferView(ptr, a._count)
+// CHECK:    self = _overrideLifetime(bv, copying: a)
+// CHECK:  }
+// CHECK:  #else
+// CHECK:  @lifetime(copy a)
+// CHECK:  @inlinable internal init(_ ptr: Swift.UnsafeRawBufferPointer, _ a: consuming lifetime_underscored_dependence.AnotherView) {
+// CHECK:    let bv = BufferView(ptr, a._count)
+// CHECK:    self = _overrideLifetime(bv, copying: a)
+// CHECK:  }
+// CHECK:  #endif
+
+// CHECK:#if compiler(>=5.3) && $Lifetimes
+// CHECK:@_lifetime(copy x)
+// CHECK:@inlinable public func derive(_ x: consuming lifetime_underscored_dependence.BufferView) -> lifetime_underscored_dependence.BufferView {
+// CHECK:  let pointer = x._ptr
+// CHECK:  let bv = BufferView(pointer, x._count)
+// CHECK:  return _overrideLifetime(bv, copying: x)
+// CHECK:}
+// CHECK:#else
+// CHECK:@lifetime(copy x)
+// CHECK:@inlinable public func derive(_ x: consuming lifetime_underscored_dependence.BufferView) -> lifetime_underscored_dependence.BufferView {
+// CHECK:  let pointer = x._ptr
+// CHECK:  let bv = BufferView(pointer, x._count)
+// CHECK:  return _overrideLifetime(bv, copying: x)
+// CHECK:}
+// CHECK:#endif
+
+// CHECK:#if compiler(>=5.3) && $Lifetimes
+// CHECK:@_lifetime(copy view)
+// CHECK:@inlinable public func consumeAndCreate(_ view: consuming lifetime_underscored_dependence.BufferView) -> lifetime_underscored_dependence.BufferView {
+// CHECK:  let pointer = view._ptr
+// CHECK:  let bv = BufferView(pointer, view._count)
+// CHECK:  return _overrideLifetime(bv, copying: view)
+// CHECK:}
+// CHECK:#else
+// CHECK:@lifetime(copy view)
+// CHECK:@inlinable public func consumeAndCreate(_ view: consuming lifetime_underscored_dependence.BufferView) -> lifetime_underscored_dependence.BufferView {
+// CHECK:  let pointer = view._ptr
+// CHECK:  let bv = BufferView(pointer, view._count)
+// CHECK:  return _overrideLifetime(bv, copying: view)
+// CHECK:}
+// CHECK:#endif
+
+// CHECK:#if compiler(>=5.3) && $Lifetimes
+// CHECK:@_lifetime(copy this, copy that)
+// CHECK:@inlinable public func deriveThisOrThat(_ this: consuming lifetime_underscored_dependence.BufferView, _ that: consuming lifetime_underscored_dependence.BufferView) -> lifetime_underscored_dependence.BufferView {
+// CHECK:  if (Int.random(in: 1..<100) == 0) {
+// CHECK:    let thisView = BufferView(this._ptr, this._count)
+// CHECK:    return _overrideLifetime(thisView, copying: this)
+// CHECK:  }
+// CHECK:  let thatView = BufferView(that._ptr, that._count)
+// CHECK:  return _overrideLifetime(thatView, copying: that)
+// CHECK:}
+// CHECK:#else
+// CHECK:@lifetime(copy this, copy that)
+// CHECK:@inlinable public func deriveThisOrThat(_ this: consuming lifetime_underscored_dependence.BufferView, _ that: consuming lifetime_underscored_dependence.BufferView) -> lifetime_underscored_dependence.BufferView {
+// CHECK:  if (Int.random(in: 1..<100) == 0) {
+// CHECK:    let thisView = BufferView(this._ptr, this._count)
+// CHECK:    return _overrideLifetime(thisView, copying: this)
+// CHECK:  }
+// CHECK:  let thatView = BufferView(that._ptr, that._count)
+// CHECK:  return _overrideLifetime(thatView, copying: that)
+// CHECK:}
+// CHECK:#endif
+
+// Check that an implicitly dependent variable accessor is guarded by LifetimeDependence.
+//
+// CHECK: extension lifetime_underscored_dependence.Container {
+// CHECK-NEXT: #if compiler(>=5.3) && $LifetimeDependence
+// CHECK-NEXT:   public var storage: lifetime_underscored_dependence.BufferView {
diff --git a/test/ModuleInterface/noncopyable_generics.swift b/test/ModuleInterface/noncopyable_generics.swift
index fc0650c7ae484..b2e793e2feeac 100644
--- a/test/ModuleInterface/noncopyable_generics.swift
+++ b/test/ModuleInterface/noncopyable_generics.swift
@@ -121,9 +121,7 @@ import NoncopyableGenerics_Misc
 // CHECK-MISC: extension {{.*}}.Outer.InnerVariation2 : Swift.Escapable where D : Swift.Escapable, A : ~Copyable {
 
 // CHECK-MISC: extension {{.*}}.Outer.InnerStruct {
-// CHECK-MISC-NEXT: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK-MISC-NEXT:   public func hello<T>(_ t: T) where T : ~Escapable
-// CHECK-MISC-NEXT:   #endif
 
 // CHECK-MISC: @_preInverseGenerics public func old_swap<T>(_ a: inout T, _ b: inout T) where T : ~Copyable
 
@@ -138,19 +136,11 @@ import NoncopyableGenerics_Misc
 // CHECK-MISC-NEXT: public func referToLoudProperGuarding(_ t: {{.*}}.LoudlyNC<Swift.String>)
 // CHECK-MISC-NEXT: public struct NoCopyPls : ~Swift.Copyable {
 // CHECK-MISC-NEXT: }
-// CHECK-MISC-NEXT: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK-MISC-NEXT: public func substCopyable(_ t: Swift.String?)
-// CHECK-MISC-NEXT: #endif
-// CHECK-MISC-NEXT: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK-MISC-NEXT: public func substGenericCopyable<T>(_ t: T?)
-// CHECK-MISC-NEXT: #endif
 
-// CHECK-MISC-NEXT: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK-MISC-NEXT: public func substNC(_ t: borrowing {{.*}}.NoCopyPls?)
-// CHECK-MISC-NEXT: #endif
-// CHECK-MISC-NEXT: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK-MISC-NEXT: public func substGenericNC<T>(_ t: borrowing T?) where T : ~Copyable
-// CHECK-MISC-NEXT: #endif
 
 // CHECK-MISC:      public protocol Publik : ~Copyable {
 // CHECK-MISC-NEXT: }
diff --git a/test/ModuleInterface/nonescapable_types.swift b/test/ModuleInterface/nonescapable_types.swift
index 4ea5418897f9a..6780310ca1862 100644
--- a/test/ModuleInterface/nonescapable_types.swift
+++ b/test/ModuleInterface/nonescapable_types.swift
@@ -5,22 +5,17 @@
 
 // REQUIRES: swift_feature_LifetimeDependence
 
-// CHECK: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK: public protocol P : ~Escapable {
 // CHECK:   associatedtype A
 // CHECK: }
-// CHECK: #endif
 public protocol P: ~Escapable {
   associatedtype A
 }
 
-// CHECK: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK: public struct X<T> : ~Swift.Escapable where T : ~Escapable {
 // CHECK: }
-// CHECK: #endif
 public struct X<T: ~Escapable>: ~Escapable { }
 
-// CHECK: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK:      extension Test.X {
 // CHECK-NEXT:   func f()
 // CHECK:      }
@@ -28,16 +23,13 @@ extension X where T: Escapable {
   public func f() { }
 }
 
-// CHECK: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK: extension Test.X where T : ~Escapable {
 // CHECK:   public func g(other: borrowing T)
 // CHECK: }
-// CHECK: #endif
 extension X where T: ~Escapable {
   public func g(other: borrowing T) { }
 }
 
-// CHECK: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK: public enum Y<T> : ~Swift.Escapable where T : ~Escapable {
 // CHECK:   case none
 // CHECK:   case some(T)
@@ -49,19 +41,15 @@ public enum Y<T: ~Escapable>: ~Escapable {
 
 extension Y: Escapable where T: Escapable { }
 
-// CHECK: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK: @lifetime(copy y)
 // CHECK: public func derive<T>(_ y: Test.Y<T>) -> Test.Y<T> where T : ~Escapable
-// CHECK: #endif
 @lifetime(copy y)
 public func derive<T : ~Escapable>(_ y: Y<T>) -> Y<T> {
   y
 }
 
-// CHECK: #if compiler(>=5.3) && $NonescapableTypes
 // CHECK: @lifetime(copy x)
 // CHECK: public func derive<T>(_ x: Test.X<T>) -> Test.X<T> where T : ~Escapable
-// CHECK: #endif
 @lifetime(copy x)
 public func derive<T : ~Escapable>(_ x: X<T>) -> X<T> {
   x
diff --git a/test/ModuleInterface/nonexhaustive_attr.swift b/test/ModuleInterface/nonexhaustive_attr.swift
new file mode 100644
index 0000000000000..78c4484d1d241
--- /dev/null
+++ b/test/ModuleInterface/nonexhaustive_attr.swift
@@ -0,0 +1,25 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-emit-module-interface(%t/Library.swiftinterface) %s -module-name Library
+// RUN: %target-swift-typecheck-module-from-interface(%t/Library.swiftinterface) -module-name Library
+// RUN: %FileCheck %s < %t/Library.swiftinterface
+
+// CHECK: #if compiler(>=5.3) && $NonexhaustiveAttribute
+// CHECK-NEXT: @nonexhaustive public enum E {
+// CHECK-NEXT: }
+// CHECK-NEXT: #else
+// CHECK-NEXT: public enum E {
+// CHECK-NEXT: }
+// CHECK-NEXT: #endif
+@nonexhaustive
+public enum E {
+}
+
+// CHECK: #if compiler(>=5.3) && $NonexhaustiveAttribute
+// CHECK-NEXT: @nonexhaustive(warn) public enum F {
+// CHECK: #else
+// CHECK-NEXT: public enum F {
+// CHECK: #endif
+@nonexhaustive(warn)
+public enum F {
+  case a
+}
diff --git a/test/ModuleInterface/nonexhaustive_enums.swift b/test/ModuleInterface/nonexhaustive_enums.swift
new file mode 100644
index 0000000000000..c44ad74bdfab9
--- /dev/null
+++ b/test/ModuleInterface/nonexhaustive_enums.swift
@@ -0,0 +1,144 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+/// Build the library
+// RUN: %target-swift-frontend -emit-module %t/src/Lib.swift \
+// RUN:   -module-name Lib \
+// RUN:   -emit-module-path %t/Lib.swiftmodule
+
+// RUN: %target-swift-frontend -typecheck %t/src/TestChecking.swift \
+// RUN:   -swift-version 5 -module-name Client -I %t \
+// RUN:   -verify
+
+// Test to make sure that if the library and client are in the same package enums are checked exhaustively
+
+/// Build the library
+// RUN: %target-swift-frontend -emit-module %t/src/Lib.swift \
+// RUN:   -module-name Lib \
+// RUN:   -package-name Test \
+// RUN:   -emit-module-path %t/Lib.swiftmodule
+
+// Different module but the same package
+// RUN: %target-swift-frontend -typecheck %t/src/TestSamePackage.swift \
+// RUN:   -swift-version 5 -module-name Client -I %t \
+// RUN:   -package-name Test \
+// RUN:   -verify
+
+// Different module but the same package
+// RUN: %target-swift-frontend -typecheck %t/src/TestSwift6.swift \
+// RUN:   -swift-version 6 -module-name Client -I %t \
+// RUN:   -verify
+
+//--- Lib.swift
+
+@nonexhaustive
+public enum E {
+  case a
+}
+
+@nonexhaustive(warn)
+public enum PE {
+  case a
+}
+
+@frozen
+public enum F {
+  case a
+  case b
+}
+
+func test_same_module(e: E, f: F) {
+  switch e { // Ok
+  case .a: break 
+  }
+
+  switch f { // Ok
+  case .a: break
+  case .b: break
+  }
+}
+
+//--- TestChecking.swift
+import Lib
+
+func test(e: E, pe: PE, f: F) {
+  // `E` is marked as `@nonexhaustive` which means it gets new semantics
+
+  switch e {
+  // expected-warning@-1 {{switch covers known cases, but 'E' may have additional unknown values, possibly added in future versions; this is an error in the Swift 6 language mode}}
+  // expected-note@-2 {{handle unknown values using "@unknown default"}}
+  case .a: break
+  }
+
+  switch e { // Ok (no warnings)
+  case .a: break
+  @unknown default: break
+  }
+
+  switch pe {
+  // expected-warning@-1 {{switch covers known cases, but 'PE' may have additional unknown values, possibly added in future versions; this will be an error in a future Swift language mode}}
+  // expected-note@-2 {{handle unknown values using "@unknown default"}}
+  case .a: break
+  }
+
+  // `F` is marked as `@frozen` which means regular rules apply.
+
+  switch f { // Ok (no errors because `F` is `@frozen`)
+  case .a: break
+  case .b: break
+  }
+
+  switch f { // expected-error {{switch must be exhaustive}} expected-note {{dd missing case: '.b'}}
+  case .a: break
+  }
+  
+  switch f { // expected-warning {{switch must be exhaustive}} expected-note {{dd missing case: '.b'}}
+  case .a: break
+  @unknown default: break
+  }
+}
+
+//--- TestSamePackage.swift
+import Lib
+
+func test_no_default(e: E, f: F) {
+  switch e { // Ok
+  case .a: break
+  }
+
+  switch e { // expected-warning {{switch must be exhaustive}} expected-note {{dd missing case: '.a'}}
+  @unknown default: break
+  }
+
+  switch f { // expected-error {{switch must be exhaustive}} expected-note {{dd missing case: '.b'}}
+  case .a: break
+  }
+
+  switch f { // expected-warning {{switch must be exhaustive}} expected-note {{dd missing case: '.b'}}
+  case .a: break
+  @unknown default: break
+  }
+}
+
+//--- TestSwift6.swift
+import Lib
+
+func test(e: E, pe: PE, f: F) {
+  switch e {
+  // expected-error@-1 {{switch covers known cases, but 'E' may have additional unknown values, possibly added in future versions}}
+  // expected-note@-2 {{handle unknown values using "@unknown default"}}
+  case .a: break
+  }
+
+  switch e { // Ok (no warnings)
+  case .a: break
+  @unknown default: break
+  }
+
+  switch pe {
+  // expected-warning@-1 {{switch covers known cases, but 'PE' may have additional unknown values, possibly added in future versions; this will be an error in a future Swift language mode}}
+  // expected-note@-2 {{handle unknown values using "@unknown default"}}
+  case .a: break
+  }
+}
diff --git a/test/ModuleInterface/nsmanaged-attr.swift b/test/ModuleInterface/nsmanaged-attr.swift
index 55d2eaccf2ad9..19a310e041cf2 100644
--- a/test/ModuleInterface/nsmanaged-attr.swift
+++ b/test/ModuleInterface/nsmanaged-attr.swift
@@ -16,24 +16,24 @@
 import CoreData
 import Foundation
 
-// CHECK: @objc @_inheritsConvenienceInitializers public class MyObject : CoreData.NSManagedObject {
+// CHECK: @objc @_inheritsConvenienceInitializers{{ nonisolated | }}public class MyObject : CoreData.NSManagedObject {
 public class MyObject: NSManagedObject {
-  // CHECK: @objc @NSManaged dynamic public var myVar: Swift.String {
+  // CHECK: @objc @NSManaged{{ nonisolated | }}dynamic public var myVar: Swift.String {
   // CHECK-NEXT: @objc get
   // CHECK-NEXT: @objc set
   // CHECK-NEXT: }
   @NSManaged public var myVar: String
-  // CHECK: @NSManaged @objc dynamic public var myVar2: Swift.String {
+  // CHECK: @NSManaged @objc{{ nonisolated | }}dynamic public var myVar2: Swift.String {
   // CHECK-NEXT: @objc get
   // CHECK-NEXT: @objc set
   // CHECK-NEXT: }
   @NSManaged @objc public var myVar2: String
-  // CHECK: @NSManaged @objc dynamic public var myVar3: Swift.String {
+  // CHECK: @NSManaged @objc dynamic{{ nonisolated | }}public var myVar3: Swift.String {
   // CHECK-NEXT: @objc get
   // CHECK-NEXT: @objc set
   // CHECK-NEXT: }
   @NSManaged @objc dynamic public var myVar3: String
-  // CHECK: @NSManaged @objc dynamic public var myVar4: Swift.String {
+  // CHECK: @NSManaged @objc dynamic{{ nonisolated | }}public var myVar4: Swift.String {
   // CHECK-NEXT: @objc get
   // CHECK-NEXT: }
   @NSManaged @objc dynamic public private(set) var myVar4: String
diff --git a/test/ModuleInterface/objc_implementation.swift b/test/ModuleInterface/objc_implementation.swift
index fd6c38d05b791..f047a8a6fff79 100644
--- a/test/ModuleInterface/objc_implementation.swift
+++ b/test/ModuleInterface/objc_implementation.swift
@@ -42,6 +42,12 @@ import Foundation
     didSet { print(implProperty) }
   }
 
+  // CHECK-NOT: var letProperty1:
+  @objc public let letProperty1: Int32
+
+  // CHECK-DAG: @nonobjc public var letProperty2: Swift.Int32 { get }
+  @nonobjc public let letProperty2: Int32
+
   // CHECK-DAG: final public var implProperty2: ObjectiveC.NSObject? { get set }
   public final var implProperty2: NSObject?
 
diff --git a/test/ModuleInterface/opaque-result-types.swift b/test/ModuleInterface/opaque-result-types.swift
index ba26e259393c9..dbf0ed173a0e2 100644
--- a/test/ModuleInterface/opaque-result-types.swift
+++ b/test/ModuleInterface/opaque-result-types.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-emit-module-interface(%t/OpaqueResultTypes.swiftinterface) %s -module-name OpaqueResultTypes
 // RUN: %target-swift-typecheck-module-from-interface(%t/OpaqueResultTypes.swiftinterface) -module-name OpaqueResultTypes
 // RUN: %FileCheck %s < %t/OpaqueResultTypes.swiftinterface
-// RUN: %target-swift-frontend -I %t -typecheck -verify %S/Inputs/opaque-result-types-client.swift
+// RUN: %target-swift-frontend -I %t -typecheck -verify -verify-ignore-unrelated %S/Inputs/opaque-result-types-client.swift
 
 public protocol Foo {}
 extension Int: Foo {}
diff --git a/test/ModuleInterface/originally-defined-attr.swift b/test/ModuleInterface/originally-defined-attr.swift
index 0d4097b7d11dc..6c65783066bbe 100644
--- a/test/ModuleInterface/originally-defined-attr.swift
+++ b/test/ModuleInterface/originally-defined-attr.swift
@@ -14,6 +14,7 @@
 // RUN: %FileCheck %s < %t/printed-module.txt
 
 // CHECK: @_originallyDefinedIn(module: "another", macOS 13.13)
+// CHECK-LABEL: protocol SimpleProto
 @available(OSX 10.8, *)
 @_originallyDefinedIn(module: "another", OSX 13.13)
 public protocol SimpleProto { }
@@ -22,6 +23,7 @@ public protocol SimpleProto { }
 // CHECK: @_originallyDefinedIn(module: "another_original", macOS 2.0)
 // CHECK: @_originallyDefinedIn(module: "another_original", iOS 3.0)
 // CHECK: @_originallyDefinedIn(module: "another_original", watchOS 4.0)
+// CHECK-LABEL: struct SimpleStruct
 @available(tvOS 0.7, OSX 1.1, iOS 2.1, watchOS 3.2, *)
 @_originallyDefinedIn(module: "original", tvOS 1.0)
 @_originallyDefinedIn(module: "another_original", OSX 2.0, iOS 3.0, watchOS 4.0)
@@ -29,23 +31,57 @@ public struct SimpleStruct {}
 
 // CHECK: @_originallyDefinedIn(module: "other0", macOS 10.10)
 // CHECK: @_originallyDefinedIn(module: "other0", iOS 8.0)
+// CHECK-LABEL: struct SimpleThingInAlphabeticalOrderForMacros0
 @available(tvOS 0.7, OSX 1.1, iOS 2.1, watchOS 3.2, *)
 @_originallyDefinedIn(module: "other0", _iOS8Aligned)
 public struct SimpleThingInAlphabeticalOrderForMacros0 {}
 
 // CHECK: @_originallyDefinedIn(module: "other1", iOS 9.0)
 // CHECK: @_originallyDefinedIn(module: "other1", macOS 10.11)
+// CHECK-LABEL: struct SimpleThingInAlphabeticalOrderForMacros1
 @available(tvOS 0.7, OSX 1.1, iOS 2.1, watchOS 3.2, *)
 @_originallyDefinedIn(module: "other1", _iOS9, _macOS10_11)
 public struct SimpleThingInAlphabeticalOrderForMacros1 {}
 
 // CHECK: @_originallyDefinedIn(module: "other2", macOS 10.11)
+// CHECK-LABEL: struct SimpleThingInAlphabeticalOrderForMacros2
 @available(tvOS 0.7, OSX 1.1, iOS 2.1, watchOS 3.2, *)
 @_originallyDefinedIn(module: "other2", _myProject 1.0)
 public struct SimpleThingInAlphabeticalOrderForMacros2 {}
 
 // CHECK: @_originallyDefinedIn(module: "another", macOS 13.13)
+// CHECK-LABEL: struct SimpleThingInAlphabeticalOrderForMacros3_UsableFromInline
 @available(OSX 10.8, *)
 @_originallyDefinedIn(module: "another", OSX 13.13)
 @usableFromInline
 internal struct SimpleThingInAlphabeticalOrderForMacros3_UsableFromInline {}
+
+// CHECK: @_originallyDefinedIn(module: "pre26", macOS 26.0)
+// CHECK: @_originallyDefinedIn(module: "pre26", iOS 26.0)
+// CHECK: @_originallyDefinedIn(module: "pre26", watchOS 26.0)
+// CHECK: @_originallyDefinedIn(module: "pre26", tvOS 26.0)
+// CHECK: @_originallyDefinedIn(module: "pre26", visionOS 26.0)
+// CHECK-LABEL: struct SimpleThingInAlphabeticalOrderForMacros4_VersionsMappingTo26
+@available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+@_originallyDefinedIn(module: "pre26", macOS 16, iOS 19, watchOS 12, tvOS 19, visionOS 3)
+public struct SimpleThingInAlphabeticalOrderForMacros4_VersionsMappingTo26 {}
+
+// CHECK: @_originallyDefinedIn(module: "pre27", macOS 27)
+// CHECK: @_originallyDefinedIn(module: "pre27", iOS 27)
+// CHECK: @_originallyDefinedIn(module: "pre27", watchOS 27)
+// CHECK: @_originallyDefinedIn(module: "pre27", tvOS 27)
+// CHECK: @_originallyDefinedIn(module: "pre27", visionOS 27)
+// CHECK-LABEL: struct SimpleThingInAlphabeticalOrderForMacros5_VersionsMappingTo27
+@available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+@_originallyDefinedIn(module: "pre27", macOS 17, iOS 20, watchOS 13, tvOS 20, visionOS 4)
+public struct SimpleThingInAlphabeticalOrderForMacros5_VersionsMappingTo27 {}
+
+// CHECK: @_originallyDefinedIn(module: "pre26", macOS 26)
+// CHECK: @_originallyDefinedIn(module: "pre26", iOS 26)
+// CHECK: @_originallyDefinedIn(module: "pre26", watchOS 26)
+// CHECK: @_originallyDefinedIn(module: "pre26", tvOS 26)
+// CHECK: @_originallyDefinedIn(module: "pre26", visionOS 26)
+// CHECK-LABEL: struct SimpleThingInAlphabeticalOrderForMacros6_Version26
+@available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+@_originallyDefinedIn(module: "pre26", macOS 26, iOS 26, watchOS 26, tvOS 26, visionOS 26)
+public struct SimpleThingInAlphabeticalOrderForMacros6_Version26 {}
diff --git a/test/ModuleInterface/ossa-modules/sdk-test-stdlib-ossa.swift b/test/ModuleInterface/ossa-modules/sdk-test-stdlib-ossa.swift
index 41d380d50ee01..29e2cb6b4909e 100644
--- a/test/ModuleInterface/ossa-modules/sdk-test-stdlib-ossa.swift
+++ b/test/ModuleInterface/ossa-modules/sdk-test-stdlib-ossa.swift
@@ -13,7 +13,7 @@
 // RUN: %empty-directory(%t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule)
 // RUN: %empty-directory(%t/PreBuiltSDKModules)
 
-// RUN: %target-swift-frontend -c -emit-module-interface-path %t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule/%target-swiftinterface-name -emit-module-path %t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule/%target-swiftmodule-name -o %t/Swift.o -parse-stdlib -module-name Swift -enable-library-evolution -module-cache-path %t/TempModuleCacheLibrary -swift-version 5 %s -disable-objc-interop -enable-ossa-modules
+// RUN: %target-swift-frontend -c -emit-module-interface-path %t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule/%target-swiftinterface-name -emit-module-path %t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule/%target-swiftmodule-name -o %t/Swift.o -parse-stdlib -module-name Swift -enable-library-evolution -module-cache-path %t/TempModuleCacheLibrary -swift-version 5 %s -disable-objc-interop
 
 // RUN: %swift_build_sdk_interfaces_base -o %t/PreBuiltSDKModules -j 1 -sdk %t/SDK -module-cache-path %t/TempModuleCacheBuilder %t/SDK -v
 
@@ -23,7 +23,7 @@
 
 // In this case also, we should not rebuild.
 
-// RUN: %target-swift-frontend -typecheck -sdk '%t/SDK' -prebuilt-module-cache-path '%t/PreBuiltSDKModules' -module-cache-path %t/TempModuleCacheOther -resource-dir '' -parse-stdlib -Rmodule-interface-rebuild %S/Inputs/sdk-test-stdlib-no-ossa-referent-no-rebuild-remark.swift -verify -enable-ossa-modules
+// RUN: %target-swift-frontend -typecheck -sdk '%t/SDK' -prebuilt-module-cache-path '%t/PreBuiltSDKModules' -module-cache-path %t/TempModuleCacheOther -resource-dir '' -parse-stdlib -Rmodule-interface-rebuild %S/Inputs/sdk-test-stdlib-no-ossa-referent-no-rebuild-remark.swift -verify
 
 // Flaky hangs: rdar://77288690
 // UNSUPPORTED: CPU=arm64, CPU=arm64e
diff --git a/test/ModuleInterface/preconcurrency_imports.swift b/test/ModuleInterface/preconcurrency_imports.swift
new file mode 100644
index 0000000000000..238ba9a1ec17e
--- /dev/null
+++ b/test/ModuleInterface/preconcurrency_imports.swift
@@ -0,0 +1,37 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module %t/PreconcurrencyLib.swift -module-name PreconcurrencyLib -swift-version 5 -enable-library-evolution -emit-module-path %t/PreconcurrencyLib.swiftmodule -emit-module-interface-path %t/PreconcurrencyLib.swiftinterface
+// RUN: %target-swift-frontend -emit-module %t/OtherLib.swift -module-name OtherLib -swift-version 5 -enable-library-evolution -emit-module-path %t/OtherLib.swiftmodule -emit-module-interface-path %t/OtherLib.swiftinterface
+
+// RUN: %target-swift-emit-module-interface(%t/ClientLib.swiftinterface) -swift-version 6 %t/ClientLib_file1.swift %t/ClientLib_file2.swift -module-name ClientLib -I %t
+// RUN: %target-swift-typecheck-module-from-interface(%t/ClientLib.swiftinterface) -module-name ClientLib -I %t
+// RUN: %FileCheck %s < %t/ClientLib.swiftinterface
+
+// CHECK: {{^}}@preconcurrency import OtherLib
+// CHECK: {{^}}@preconcurrency import PreconcurrencyLib
+// CHECK: public struct Struct1 : Swift.Sendable
+// CHECK: public struct Struct2
+
+//--- PreconcurrencyLib.swift
+
+public class C {}
+
+//--- OtherLib.swift
+// Intentionally empty
+
+//--- ClientLib_file1.swift
+
+@preconcurrency public import PreconcurrencyLib
+public import OtherLib
+
+public struct Struct1: Sendable {
+  public var c: C
+}
+
+//--- ClientLib_file2.swift
+
+internal import PreconcurrencyLib
+@preconcurrency internal import OtherLib
+
+public struct Struct2 {}
diff --git a/test/ModuleInterface/private-stored-member-type-layout.swift b/test/ModuleInterface/private-stored-member-type-layout.swift
index fba3799c8b993..494aa191c920f 100644
--- a/test/ModuleInterface/private-stored-member-type-layout.swift
+++ b/test/ModuleInterface/private-stored-member-type-layout.swift
@@ -28,17 +28,17 @@ import PrivateStoredMembers
 // CHECK-EXEC: swiftcc void @"$s{{[^ ]+}}8makeUseryyF"() #0 {
 public func makeUser() {
   let ptr = UnsafeMutablePointer<MyStruct>.allocate(capacity: 1)
-  // CHECK-EXEC: %.publicEndVar = getelementptr inbounds [[MYSTRUCT]], ptr %{{[0-9]+}}, i32 0, i32 [[PUBLIC_END_VAR_IDX:12]]
-  // CHECK-EXEC: %.publicEndVar._value = getelementptr inbounds %Ts5Int64V, ptr %.publicEndVar, i32 0, i32 0
+  // CHECK-EXEC: %.publicEndVar = getelementptr inbounds{{.*}} [[MYSTRUCT]], ptr %{{[0-9]+}}, i32 0, i32 [[PUBLIC_END_VAR_IDX:12]]
+  // CHECK-EXEC: %.publicEndVar._value = getelementptr inbounds{{.*}} %Ts5Int64V, ptr %.publicEndVar, i32 0, i32 0
   // CHECK-EXEC: store i64 4, ptr %.publicEndVar._value
   ptr.pointee.publicEndVar = 4
 
-  // CHECK-EXEC: %.publicEndVar1 = getelementptr inbounds [[MYSTRUCT]], ptr %{{[0-9]+}}, i32 0, i32 [[PUBLIC_END_VAR_IDX]]
-  // CHECK-EXEC: %.publicEndVar1._value = getelementptr inbounds %Ts5Int64V, ptr %.publicEndVar1, i32 0, i32 0
+  // CHECK-EXEC: %.publicEndVar1 = getelementptr inbounds{{.*}} [[MYSTRUCT]], ptr %{{[0-9]+}}, i32 0, i32 [[PUBLIC_END_VAR_IDX]]
+  // CHECK-EXEC: %.publicEndVar1._value = getelementptr inbounds{{.*}} %Ts5Int64V, ptr %.publicEndVar1, i32 0, i32 0
   // CHECK-EXEC: [[PUBLIC_END_VAR_LOAD:%[0-9]+]] = load i64, ptr %.publicEndVar1._value, align 8
 
-  // CHECK-EXEC: %.publicVar = getelementptr inbounds [[MYSTRUCT]], ptr %{{[0-9]+}}, i32 0, i32 0
-  // CHECK-EXEC: %.publicVar._value = getelementptr inbounds %Ts5Int64V, ptr %.publicVar, i32 0, i32 0
+  // CHECK-EXEC: %.publicVar = getelementptr inbounds{{.*}} [[MYSTRUCT]], ptr %{{[0-9]+}}, i32 0, i32 0
+  // CHECK-EXEC: %.publicVar._value = getelementptr inbounds{{.*}} %Ts5Int64V, ptr %.publicVar, i32 0, i32 0
   // CHECK-EXEC: store i64 [[PUBLIC_END_VAR_LOAD]], ptr %.publicVar._value, align 8
   ptr.pointee.publicVar = ptr.pointee.publicEndVar
   ptr.deallocate()
diff --git a/test/ModuleInterface/property_wrappers.swift b/test/ModuleInterface/property_wrappers.swift
index bec1710696a99..08995fd778181 100644
--- a/test/ModuleInterface/property_wrappers.swift
+++ b/test/ModuleInterface/property_wrappers.swift
@@ -9,34 +9,46 @@
 
 @propertyWrapper
 public struct Wrapper<T> {
-  public var value: T
+  public var wrappedValue: T
 
-  public var wrappedValue: T {
-    get { value }
-    set { value = newValue }
+  public init(wrappedValue: T) {
+    self.wrappedValue = wrappedValue
   }
 }
 
 @propertyWrapper
 public struct WrapperWithInitialValue<T> {
-  private var value: T
-  
-  public var wrappedValue: T {
-    get { value }
-    set { value = newValue }
-  }
+  public var wrappedValue: T
 
   public init(initialValue: T) {
-    self.value = initialValue
+    self.wrappedValue = initialValue
   }
 
   public init(alternate value: T) {
-    self.value = value
+    self.wrappedValue = value
   }
 
   public var projectedValue: Wrapper<T> {
-    get { Wrapper(value: value) }
-    set { value = newValue.value }
+    get { Wrapper(wrappedValue: wrappedValue) }
+    set { wrappedValue = newValue.wrappedValue }
+  }
+}
+
+@propertyWrapper
+public struct ProjectedValueWrapper<T> {
+  public var wrappedValue: T
+
+  public init(wrappedValue: T) {
+    self.wrappedValue = wrappedValue
+  }
+
+  public init(projectedValue: Wrapper<T>) {
+    self.wrappedValue = projectedValue.wrappedValue
+  }
+
+  public var projectedValue: Wrapper<T> {
+    get { Wrapper(wrappedValue: wrappedValue) }
+    set { wrappedValue = newValue.wrappedValue }
   }
 }
 
@@ -64,4 +76,22 @@ public struct HasWrappers {
   // CHECK-NEXT: _modify
   // CHECK-NEXT: }  
   @WrapperWithInitialValue(alternate: false) public var z
+
+  // CHECK: public func hasParameterWithImplementationWrapper(x: Swift.Int)
+  public func hasParameterWithImplementationWrapper(@Wrapper x: Int) { }
+
+  // CHECK: public func hasParameterWithImplementationWrapperComposed(x: Swift.Int)
+  public func hasParameterWithImplementationWrapperComposed(@Wrapper @ProjectedValueWrapper x: Int) { }
+
+  // CHECK: @inlinable public func hasParameterWithImplementationWrapperInlinable(@TestResilient.Wrapper x: Swift.Int)
+  @inlinable public func hasParameterWithImplementationWrapperInlinable(@Wrapper x: Int) { }
+
+  // CHECK: @_alwaysEmitIntoClient public func hasParameterWithImplementationWrapperAEIC(@TestResilient.Wrapper x: Swift.Int)
+  @_alwaysEmitIntoClient public func hasParameterWithImplementationWrapperAEIC(@Wrapper x: Int) { }
+
+  // CHECK: public func hasParameterWithAPIWrapper(@TestResilient.ProjectedValueWrapper x: Swift.Int)
+  public func hasParameterWithAPIWrapper(@ProjectedValueWrapper x: Int) { }
+
+  // CHECK: public func hasParameterWithAPIWrapperComposed(@TestResilient.ProjectedValueWrapper @TestResilient.Wrapper x: Swift.Int)
+  public func hasParameterWithAPIWrapperComposed(@ProjectedValueWrapper @Wrapper x: Int) { }
 }
diff --git a/test/ModuleInterface/swiftinterface-compiler-version-option.swift b/test/ModuleInterface/swiftinterface-compiler-version-option.swift
index ca58392190112..69bc50e47849d 100644
--- a/test/ModuleInterface/swiftinterface-compiler-version-option.swift
+++ b/test/ModuleInterface/swiftinterface-compiler-version-option.swift
@@ -25,12 +25,12 @@
 /// Check option in swiftinterface
 // RUN: cat %t/Lib.swiftinterface | %FileCheck --check-prefix=CHECK-OPTION %s
 // CHECK-OPTION: swift-module-flags-ignorable:
-// CHECK-SAME-OPTION: -swift-compiler-version {{.*}}
+// CHECK-OPTION-SAME: -interface-compiler-version {{.*}}
 
 /// Check option in swiftmodule
 // RUN: llvm-bcanalyzer --dump %t/Lib.swiftmodule | %FileCheck --check-prefix=CHECK-MODULE-OPTION %s
 // CHECK-MODULE-OPTION: <OPTIONS_BLOCK
-// CHECK-NOT-MODULE-OPTION: <SWIFT_INTERFACE_COMPILER_VERSION abbrevid={{.*}}/> blob data = '{{.*}}'
+// CHECK-MODULE-OPTION-NOT: <SWIFT_INTERFACE_COMPILER_VERSION abbrevid={{.*}}/> blob data = '{{.*}}'
 // CHECK-MODULE-OPTION: </OPTIONS_BLOCK>
 
 // Drop and rebuilt swiftmodule to make sure that the version is inferred from the interface file.
diff --git a/test/ModuleInterface/using.swift b/test/ModuleInterface/using.swift
new file mode 100644
index 0000000000000..9b773ce1de003
--- /dev/null
+++ b/test/ModuleInterface/using.swift
@@ -0,0 +1,11 @@
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %s -enable-experimental-feature DefaultIsolationPerFile
+
+// RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface)
+
+// RUN: %FileCheck %s --input-file %t.swiftinterface
+
+// REQUIRES: swift_feature_DefaultIsolationPerFile
+
+using @MainActor
+
+// CHECK-NOT: using @MainActor
diff --git a/test/ModuleInterface/value_generics.swift b/test/ModuleInterface/value_generics.swift
index 4c46447e0dc38..da2de11d33880 100644
--- a/test/ModuleInterface/value_generics.swift
+++ b/test/ModuleInterface/value_generics.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-emit-module-interface(%t.swiftinterface) %s -module-name ValueGeneric -disable-availability-checking
 // RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -module-name ValueGeneric -disable-availability-checking
-// RUN: %FileCheck %s < %t.swiftinterface
+// RUN: %FileCheck --implicit-check-not=ValueGenericsNameLookup %s < %t.swiftinterface
 
 // CHECK: public struct Slab<Element, let N : Swift.Int>
 public struct Slab<Element, let N: Int> {
@@ -14,6 +14,8 @@ public struct Slab<Element, let N: Int> {
   public var count: Int {
     N
   }
+
+  public init() {}
 }
 
 // CHECK: public func usesGenericSlab<let N : Swift.Int>(_: ValueGeneric.Slab<Swift.Int, N>)
@@ -24,3 +26,24 @@ public func usesConcreteSlab(_: Slab<Int, 2>) {}
 
 // CHECK: public func usesNegativeSlab(_: ValueGeneric.Slab<Swift.String, -10>)
 public func usesNegativeSlab(_: Slab<String, -10>) {}
+
+@inlinable
+public func test() -> Int {
+  // CHECK: Slab<Int, 123>.N
+  Slab<Int, 123>.N
+}
+
+@inlinable
+public func test2() -> Int {
+  // CHECK: type(of: Slab<Int, 123>()).N
+  type(of: Slab<Int, 123>()).N
+}
+
+@inlinable
+public func test3() {
+  {
+    print(123)
+    print(123)
+    print(Slab<Int, 123>.N)
+  }()
+}
diff --git a/test/ModuleInterface/variadic-opaque-result-types.swift b/test/ModuleInterface/variadic-opaque-result-types.swift
new file mode 100644
index 0000000000000..7874a76d9b426
--- /dev/null
+++ b/test/ModuleInterface/variadic-opaque-result-types.swift
@@ -0,0 +1,122 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-emit-module-interface(%t/VariadicOpaqueResultTypes.swiftinterface) %s -module-name VariadicOpaqueResultTypes -target %target-swift-5.9-abi-triple
+// RUN: %target-swift-typecheck-module-from-interface(%t/VariadicOpaqueResultTypes.swiftinterface) -module-name VariadicOpaqueResultTypes
+// RUN: %FileCheck %s < %t/VariadicOpaqueResultTypes.swiftinterface
+
+
+///
+/// First, make sure pack expansions can appear in the generic argument list of an opaque return type.
+///
+
+public struct I1<each T>: IteratorProtocol {
+  public mutating func next() -> (some Any)? { return 3 }
+}
+
+// CHECK: public struct I1<each T> : Swift.IteratorProtocol {
+// CHECK:  public mutating func next() -> (some Any)?
+// CHECK:  public typealias Element = @_opaqueReturnTypeOf("$s25VariadicOpaqueResultTypes2I1V4nextQrSgyF", 0) __<repeat each T>
+// CHECK: }
+
+
+public struct S1<each T>: Sequence {
+  public func makeIterator() -> some IteratorProtocol {
+    return I1<repeat each T>()
+  }
+}
+
+// CHECK: public struct S1<each T> : Swift.Sequence {
+// CHECK:   public func makeIterator() -> some Swift.IteratorProtocol
+// CHECK:   public typealias Element = (@_opaqueReturnTypeOf("$s25VariadicOpaqueResultTypes2S1V12makeIteratorQryF", 0) __<repeat each T>).Element
+// CHECK:   public typealias Iterator = @_opaqueReturnTypeOf("$s25VariadicOpaqueResultTypes2S1V12makeIteratorQryF", 0) __<repeat each T>
+// CHECK: }
+
+
+public struct Scalar<T> {
+  public struct I2<U>: IteratorProtocol {
+    public mutating func next() -> (some Any)? { return 3 }
+  }
+}
+
+
+///
+/// Now, test nested types. The next example uses the old "flat" syntax, because parameter packs are not involved.
+///
+
+
+// CHECK: public struct Scalar<T> {
+// CHECK:   public struct I2<U> : Swift.IteratorProtocol {
+// CHECK:     public mutating func next() -> (some Any)?
+// CHECK:     public typealias Element = @_opaqueReturnTypeOf("$s25VariadicOpaqueResultTypes6ScalarV2I2V4nextQrSgyF", 0) __<T, U>
+// CHECK:   }
+// CHECK: }
+
+
+public struct S2: Sequence {
+  public func makeIterator() -> Scalar<Int>.I2<Bool> {
+    return .init()
+  }
+}
+
+// CHECK: public struct S2 : Swift.Sequence {
+// CHECK:   public func makeIterator() -> VariadicOpaqueResultTypes.Scalar<Swift.Int>.I2<Swift.Bool>
+// CHECK:   public typealias Element = @_opaqueReturnTypeOf("$s25VariadicOpaqueResultTypes6ScalarV2I2V4nextQrSgyF", 0) __<Swift.Int, Swift.Bool>
+// CHECK:   public typealias Iterator = VariadicOpaqueResultTypes.Scalar<Swift.Int>.I2<Swift.Bool>
+// CHECK: }
+
+
+///
+/// The remaining examples use the new nested syntax.
+///
+
+// CHECK: public struct Variadic<each T> {
+public struct Variadic<each T> {
+  public struct I3<each U>: IteratorProtocol {
+    public mutating func next() -> (some Any)? { return 3 }
+  }
+
+  // CHECK: public struct I3<each U> : Swift.IteratorProtocol {
+  // CHECK:   public mutating func next() -> (some Any)?
+  // CHECK:   public typealias Element = @_opaqueReturnTypeOf("$s25VariadicOpaqueResultTypes0A0V2I3V4nextQrSgyF", 0) __<repeat each T>.__<repeat each U>
+  // CHECK: }
+
+  public struct Middle {
+    public struct Inner<each U> {
+      public struct I4: IteratorProtocol {
+        public mutating func next() -> (some Any)? { return 3 }
+      }
+    }
+  }
+
+  // CHECK: public struct Middle {
+  // CHECK:   public struct Inner<each U> {
+  // CHECK:     public struct I4 : Swift.IteratorProtocol {
+  // CHECK:       public mutating func next() -> (some Any)?       
+  // CHECK:       public typealias Element = @_opaqueReturnTypeOf("$s25VariadicOpaqueResultTypes0A0V6MiddleV5InnerV2I4V4nextQrSgyF", 0) __<repeat each T>.__<repeat each U>
+  // CHECK:     }
+  // CHECK:   }
+  // CHECK: }
+}
+// CHECK: }
+
+// CHECK: public struct S3 : Swift.Sequence {
+// CHECK:   public func makeIterator() -> VariadicOpaqueResultTypes.Variadic<Swift.Int, Swift.Bool>.I3<Swift.Float, Swift.Double>
+// CHECK:   public typealias Element = @_opaqueReturnTypeOf("$s25VariadicOpaqueResultTypes0A0V2I3V4nextQrSgyF", 0) __<Swift.Int, Swift.Bool>.__<Swift.Float, Swift.Double>
+// CHECK:   public typealias Iterator = VariadicOpaqueResultTypes.Variadic<Swift.Int, Swift.Bool>.I3<Swift.Float, Swift.Double>
+// CHECK: }
+public struct S3: Sequence {
+  public func makeIterator() -> Variadic<Int, Bool>.I3<Float, Double> {
+    return .init()
+  }
+}
+
+// CHECK: public struct S4 : Swift.Sequence {
+// CHECK:   public func makeIterator() -> VariadicOpaqueResultTypes.Variadic<Swift.Int, Swift.Bool>.Middle.Inner<Swift.Float, Swift.Double>.I4
+// CHECK:   public typealias Element = @_opaqueReturnTypeOf("$s25VariadicOpaqueResultTypes0A0V6MiddleV5InnerV2I4V4nextQrSgyF", 0) __<Swift.Int, Swift.Bool>.__<Swift.Float, Swift.Double>
+// CHECK:   public typealias Iterator = VariadicOpaqueResultTypes.Variadic<Swift.Int, Swift.Bool>.Middle.Inner<Swift.Float, Swift.Double>.I4
+// CHECK: }
+public struct S4: Sequence {
+  public func makeIterator() -> Variadic<Int, Bool>.Middle.Inner<Float, Double>.I4 {
+    return .init()
+  }
+}
+
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/Categories_A.h b/test/NameLookup/Inputs/MemberImportVisibility/Categories_A.h
index 9a19f2eda3798..a23cc93676946 100644
--- a/test/NameLookup/Inputs/MemberImportVisibility/Categories_A.h
+++ b/test/NameLookup/Inputs/MemberImportVisibility/Categories_A.h
@@ -1,6 +1,13 @@
 @import Foundation;
 
-@interface X
+@interface Base
+- (void)overriddenInOverlayForA __attribute__((deprecated("Categories_A.h")));
+- (void)overriddenInOverlayForB __attribute__((deprecated("Categories_A.h")));
+- (void)overriddenInOverlayForC __attribute__((deprecated("Categories_A.h")));
+- (void)overriddenInSubclassInOverlayForC __attribute__((deprecated("Categories_A.h")));
+@end
+
+@interface X : Base
 @end
 
 @interface X (A)
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/Categories_A.swift b/test/NameLookup/Inputs/MemberImportVisibility/Categories_A.swift
index 797996c203f84..daa769ddafa72 100644
--- a/test/NameLookup/Inputs/MemberImportVisibility/Categories_A.swift
+++ b/test/NameLookup/Inputs/MemberImportVisibility/Categories_A.swift
@@ -3,4 +3,7 @@
 extension X {
   public func fromOverlayForA() {}
   @objc public func fromOverlayForAObjC() {}
+
+  @available(*, deprecated, message: "Categories_A.swift")
+  public override func overriddenInOverlayForA() {}
 }
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/Categories_B.swift b/test/NameLookup/Inputs/MemberImportVisibility/Categories_B.swift
index 7ff30e1ac8ae8..d04edb66ef33f 100644
--- a/test/NameLookup/Inputs/MemberImportVisibility/Categories_B.swift
+++ b/test/NameLookup/Inputs/MemberImportVisibility/Categories_B.swift
@@ -3,4 +3,7 @@
 extension X {
   public func fromOverlayForB() {}
   @objc public func fromOverlayForBObjC() {}
+
+  @available(*, deprecated, message: "Categories_B.swift")
+  public override func overriddenInOverlayForB() {}
 }
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/Categories_C.h b/test/NameLookup/Inputs/MemberImportVisibility/Categories_C.h
index 86449d690f4e0..eadaaeef7b298 100644
--- a/test/NameLookup/Inputs/MemberImportVisibility/Categories_C.h
+++ b/test/NameLookup/Inputs/MemberImportVisibility/Categories_C.h
@@ -3,3 +3,7 @@
 @interface X (C)
 - (void)fromC;
 @end
+
+@interface SubclassFromC : X
+- (instancetype)init;
+@end
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/Categories_C.swift b/test/NameLookup/Inputs/MemberImportVisibility/Categories_C.swift
index 6f711014aa7bb..ba98b40c0aea5 100644
--- a/test/NameLookup/Inputs/MemberImportVisibility/Categories_C.swift
+++ b/test/NameLookup/Inputs/MemberImportVisibility/Categories_C.swift
@@ -3,4 +3,12 @@
 extension X {
   public func fromOverlayForC() {}
   @objc public func fromOverlayForCObjC() {}
+
+  @available(*, deprecated, message: "Categories_C.swift")
+  public override func overriddenInOverlayForC() {}
+}
+
+extension SubclassFromC {
+  @available(*, deprecated, message: "Categories_C.swift")
+  public override func overriddenInSubclassInOverlayForC() {}
 }
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/Categories_E.swift b/test/NameLookup/Inputs/MemberImportVisibility/Categories_E.swift
index d75491c527cd1..4bb17fa34b6a1 100644
--- a/test/NameLookup/Inputs/MemberImportVisibility/Categories_E.swift
+++ b/test/NameLookup/Inputs/MemberImportVisibility/Categories_E.swift
@@ -1,2 +1,4 @@
 import Categories_C
 import Categories_D.Submodule
+
+public func makeSubclassFromC() -> SubclassFromC { SubclassFromC() }
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Branch.h b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Branch.h
new file mode 100644
index 0000000000000..ce39f6ec3e3f5
--- /dev/null
+++ b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Branch.h
@@ -0,0 +1,9 @@
+@import Root;
+
+@interface BranchObject : RootObject
+- (void)overridden1 __attribute__((deprecated("Branch.h")));
+@end
+
+@interface BranchObject (Branch)
+- (void)overridden3 __attribute__((deprecated("Branch.h")));
+@end
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Fruit.h b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Fruit.h
new file mode 100644
index 0000000000000..1b840d47b94fa
--- /dev/null
+++ b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Fruit.h
@@ -0,0 +1,9 @@
+@import Branch;
+
+@interface FruitObject : BranchObject
+- (void)overridden1 __attribute__((deprecated("Fruit.h")));
+@end
+
+@interface FruitObject (Fruit)
+- (void)overridden4 __attribute__((deprecated("Fruit.h")));
+@end
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Leaf.h b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Leaf.h
new file mode 100644
index 0000000000000..42e2052eeba0a
--- /dev/null
+++ b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Leaf.h
@@ -0,0 +1,15 @@
+@import Branch;
+
+@interface LeafObject : BranchObject
+- (void)overridden1 __attribute__((deprecated("Leaf.h")));
+@end
+
+@interface BranchObject (Leaf)
+- (void)overridden2 __attribute__((deprecated("Leaf.h")));
+- (void)overridden4 __attribute__((deprecated("Leaf.h")));
+@end
+
+@interface LeafObject (Leaf)
+- (void)overridden3 __attribute__((deprecated("Leaf.h")));
+@end
+
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Root.h b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Root.h
new file mode 100644
index 0000000000000..02942557c1535
--- /dev/null
+++ b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/Root.h
@@ -0,0 +1,10 @@
+@interface RootObject
+- (instancetype)init;
+- (void)overridden1 __attribute__((deprecated("Root.h")));
+- (void)overridden2 __attribute__((deprecated("Root.h")));
+@end
+
+@interface RootObject (Root)
+- (void)overridden3 __attribute__((deprecated("Root.h")));
+- (void)overridden4 __attribute__((deprecated("Root.h")));
+@end
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/module.modulemap b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/module.modulemap
new file mode 100644
index 0000000000000..ff7a412ad6a70
--- /dev/null
+++ b/test/NameLookup/Inputs/MemberImportVisibility/ObjCOverloads/module.modulemap
@@ -0,0 +1,19 @@
+module Root {
+  header "Root.h"
+  export *
+}
+
+module Branch {
+  header "Branch.h"
+  export *
+}
+
+module Leaf {
+  header "Leaf.h"
+  export *
+}
+
+module Fruit {
+  header "Fruit.h"
+  export *
+}
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/members_A.swift b/test/NameLookup/Inputs/MemberImportVisibility/members_A.swift
index 89dbdac659318..5cebe137152d9 100644
--- a/test/NameLookup/Inputs/MemberImportVisibility/members_A.swift
+++ b/test/NameLookup/Inputs/MemberImportVisibility/members_A.swift
@@ -8,20 +8,47 @@ public struct Y<T> { }
 
 extension Y: P where T: P { }
 
-public struct Z: P { }
+public struct Z: P {
+  public init() {}
+}
 
 infix operator <<<
 infix operator >>>
 infix operator <>
 
+@available(*, deprecated)
+public func shadowedByMemberOnXinA() { }
+
+@available(*, deprecated)
+public func shadowedByMemberOnXinB() { }
+
+@available(*, deprecated)
+public func shadowedByMemberOnXinC() { }
+
+@available(*, deprecated)
+public func shadowedByStaticMemberOnXinA() { }
+
+@available(*, deprecated)
+public func shadowedByStaticMemberOnXinB() { }
+
+@available(*, deprecated)
+public func shadowedByStaticMemberOnXinC() { }
+
 extension X {
   public func XinA() { }
 
+  @_spi(A)
+  public func XinA_spi() { }
+
   public var propXinA: Bool { return true }
 
   public static func <<<(a: Self, b: Self) -> Self { a }
 
   public struct NestedInA {}
+  public protocol ProtoNestedInA {}
+
+  public func shadowedByMemberOnXinA() { }
+  public static func shadowedByStaticMemberOnXinA() { }
 }
 
 extension Y {
@@ -30,13 +57,17 @@ extension Y {
   public static func <<<(a: Self, b: Self) -> Self { a }
 }
 
+extension P where Self == Z {
+  public static var zInA: Z { Z() }
+}
+
 public enum EnumInA {
   case caseInA
 }
 
 open class BaseClassInA {
-  public init() {}
   open func methodInA() {}
+  open func overriddenMethod() {}
 }
 
 public protocol ProtocolInA {
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/members_B.swift b/test/NameLookup/Inputs/MemberImportVisibility/members_B.swift
index f393a5b72adb2..05c8cd51fe03a 100644
--- a/test/NameLookup/Inputs/MemberImportVisibility/members_B.swift
+++ b/test/NameLookup/Inputs/MemberImportVisibility/members_B.swift
@@ -5,13 +5,22 @@ extension X {
   public func XinB() { }
   package func XinB_package() { }
 
+  @_spi(B)
+  public func XinB_spi() { }
+
   public var propXinB: Bool { return true }
   package var propXinB_package: Bool { return true }
 
+  public func shadowedByMemberOnXinB() { }
+  public static func shadowedByStaticMemberOnXinB() { }
+
+  public static var max: Int { return Int.min }
+
   public static func >>>(a: Self, b: Self) -> Self { b }
 
   public struct NestedInB {}
   package struct NestedInB_package {}
+  public protocol ProtoNestedInB {}
 }
 
 // Members with the same names are also declared in C.
@@ -19,6 +28,8 @@ extension X {
   public init(_ x: Int) { self.init() }
   public func ambiguous() -> Int { return 1 }
   public func ambiguousDisfavored() -> Int { return 1 }
+  public var ambiguousProp: Bool { return false }
+  public struct AmbiguousNestedType { }
 }
 
 extension Y {
@@ -27,6 +38,11 @@ extension Y {
   public static func >>>(a: Self, b: Self) -> Self { b }
 }
 
+extension P where Self == Z {
+  public static var zInB: Z { Z() }
+  public static var zAmbiguous: Z { Z() }
+}
+
 public enum EnumInB {
   case caseInB
 }
@@ -37,6 +53,7 @@ package enum EnumInB_package {
 
 open class DerivedClassInB: BaseClassInA {
   open func methodInB() {}
+  open override func overriddenMethod() {}
 }
 
 extension ProtocolInA {
diff --git a/test/NameLookup/Inputs/MemberImportVisibility/members_C.swift b/test/NameLookup/Inputs/MemberImportVisibility/members_C.swift
index 32189ea74a724..8cc0492998ad6 100644
--- a/test/NameLookup/Inputs/MemberImportVisibility/members_C.swift
+++ b/test/NameLookup/Inputs/MemberImportVisibility/members_C.swift
@@ -5,11 +5,18 @@ import members_B
 extension X {
   public func XinC() { }
 
+  @_spi(C)
+  public func XinC_spi() { }
+
   public var propXinC: Bool { return true }
 
+  public func shadowedByMemberOnXinC() { }
+  public static func shadowedByStaticMemberOnXinC() { }
+
   public static func <>(a: Self, b: Self) -> Self { a }
 
   public struct NestedInC {}
+  public protocol ProtoNestedInC {}
 }
 
 // Members with the same names are also declared in B.
@@ -17,6 +24,8 @@ extension X {
   public init(_ x: Bool) { self.init() }
   public func ambiguous() -> Bool { return false }
   @_disfavoredOverload public func ambiguousDisfavored() -> Bool { return false }
+  public var ambiguousProp: Bool { return true }
+  public struct AmbiguousNestedType { }
 }
 
 extension Y {
@@ -25,12 +34,19 @@ extension Y {
   public static func <>(a: Self, b: Self) -> Self { a }
 }
 
+extension P where Self == Z {
+  public static var zInC: Z { Z() }
+  public static var zAmbiguous: Z { Z() }
+}
+
 public enum EnumInC {
   case caseInC
 }
 
 open class DerivedClassInC: DerivedClassInB {
   open func methodInC() {}
+  open override func overriddenMethod() {}
+  public func asDerivedClassInB() -> DerivedClassInB { return self }
 }
 
 extension ProtocolInA {
diff --git a/test/NameLookup/Inputs/NIOFoundationCompat.swift b/test/NameLookup/Inputs/NIOFoundationCompat.swift
index 54bae53f87d56..6473c87c09005 100644
--- a/test/NameLookup/Inputs/NIOFoundationCompat.swift
+++ b/test/NameLookup/Inputs/NIOFoundationCompat.swift
@@ -1,7 +1,7 @@
 import Foundation
 
 extension Data {
-  @_inlineable
+  @inlinable
   public func withUnsafeBytes<R>(_ body: (UnsafeRawBufferPointer) throws -> R) rethrows -> R {
     let r: R? = nil
     return r!
diff --git a/test/NameLookup/Inputs/accessibility_other.swift b/test/NameLookup/Inputs/accessibility_other.swift
index 8fcfbd44739b2..4c001873d1ea0 100644
--- a/test/NameLookup/Inputs/accessibility_other.swift
+++ b/test/NameLookup/Inputs/accessibility_other.swift
@@ -2,7 +2,7 @@ import has_accessibility
 
 public let a = 0 // expected-note * {{did you mean 'a'?}}
 internal let b = 0 // expected-note * {{did you mean 'b'?}}
-private let c = 0 // expected-note {{'c' declared here}}
+private let c = 0 // expected-note 2 {{'c' declared here}}
 
 extension Foo {
   public static func a() {}
diff --git a/test/NameLookup/accessibility.swift b/test/NameLookup/accessibility.swift
index eac3b6b186d0b..b0251346452bf 100644
--- a/test/NameLookup/accessibility.swift
+++ b/test/NameLookup/accessibility.swift
@@ -2,7 +2,7 @@
 // RUN: cp %s %t/main.swift
 
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/has_accessibility.swift -D DEFINE_VAR_FOR_SCOPED_IMPORT -enable-testing
-// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %S/Inputs/accessibility_other.swift -module-name accessibility -I %t -sdk "" -enable-access-control -verify -verify-ignore-unknown
+// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %S/Inputs/accessibility_other.swift -module-name accessibility -I %t -sdk "" -enable-access-control -verify -verify-ignore-unrelated -verify-ignore-unknown
 // RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %S/Inputs/accessibility_other.swift -module-name accessibility -I %t -sdk "" -disable-access-control -D ACCESS_DISABLED
 // RUN: not %target-swift-frontend -typecheck -primary-file %t/main.swift %S/Inputs/accessibility_other.swift -module-name accessibility -I %t -sdk "" -D TESTABLE 2>&1 | %FileCheck -check-prefix=TESTABLE %s
 
@@ -37,7 +37,7 @@ markUsed(z) // expected-error {{cannot find 'z' in scope}}
 
 markUsed(a)
 markUsed(b)
-markUsed(c) // expected-error {{cannot find 'c' in scope}}
+markUsed(c) // expected-error {{'c' is inaccessible due to 'private' protection level}}
 
 Foo.x()
 Foo.y() // expected-error {{'y' is inaccessible due to 'internal' protection level}}
@@ -64,7 +64,7 @@ _ = PrivateInit() // expected-error {{'PrivateInit' initializer is inaccessible
 // TESTABLE: :[[@LINE-1]]:{{[^:]+}}: error: 'PrivateInit' initializer is inaccessible due to 'private' protection level
 
 var s = StructWithPrivateSetter()
-// expected-note@-1 3{{did you mean 's'?}}
+// expected-note@-1 2{{did you mean 's'?}}
 s.x = 42 // expected-error {{cannot assign to property: 'x' setter is inaccessible}}
 
 class Sub : Base {
diff --git a/test/NameLookup/custom_attrs_ambiguous.swift b/test/NameLookup/custom_attrs_ambiguous.swift
index 6512e44d610bf..cae1d394cb1fe 100644
--- a/test/NameLookup/custom_attrs_ambiguous.swift
+++ b/test/NameLookup/custom_attrs_ambiguous.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -I %t -o %t %S/Inputs/custom_attrs_A.swift
 // RUN: %target-swift-frontend -emit-module -I %t -o %t %S/Inputs/custom_attrs_B.swift
-// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unknown -I %t %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -verify-ignore-unknown -I %t %s
 import custom_attrs_A
 import custom_attrs_B
 
diff --git a/test/NameLookup/library.swift b/test/NameLookup/library.swift
index 5b85f5e7923f3..610ae0c958194 100644
--- a/test/NameLookup/library.swift
+++ b/test/NameLookup/library.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck %s -I %S/Inputs -enable-source-import -parse-as-library -verify
+// RUN: %target-swift-frontend -typecheck %s -I %S/Inputs -enable-source-import -parse-as-library -verify -verify-ignore-unrelated
 
 // Name lookup is global in a library.
 var x : x_ty = 4
diff --git a/test/NameLookup/member_import_visibility.swift b/test/NameLookup/member_import_visibility.swift
new file mode 100644
index 0000000000000..bdd2d5833cd0a
--- /dev/null
+++ b/test/NameLookup/member_import_visibility.swift
@@ -0,0 +1,169 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/MemberImportVisibility/members_A.swift
+// RUN: %target-swift-frontend -emit-module -I %t -o %t -package-name TestPackage %S/Inputs/MemberImportVisibility/members_B.swift
+// RUN: %target-swift-frontend -emit-module -I %t -o %t %S/Inputs/MemberImportVisibility/members_C.swift
+// RUN: %target-swift-frontend -typecheck %s -I %t -verify -verify-ignore-unrelated -swift-version 5 -package-name TestPackage -verify-additional-prefix ambiguity-
+// RUN: %target-swift-frontend -typecheck %s -I %t -verify -verify-ignore-unrelated -swift-version 6 -package-name TestPackage -verify-additional-prefix ambiguity-
+// RUN: %target-swift-frontend -typecheck %s -I %t -verify -verify-ignore-unrelated -swift-version 5 -package-name TestPackage -enable-upcoming-feature MemberImportVisibility -verify-additional-prefix member-visibility-
+
+// REQUIRES: swift_feature_MemberImportVisibility
+
+import members_C
+// expected-member-visibility-note 28{{add import of module 'members_B'}}{{1-1=internal import members_B\n}}
+
+
+func testExtensionMembers(x: X, y: Y<Z>) {
+  x.XinA()
+  x.XinA_spi() // expected-error{{'XinA_spi' is inaccessible due to '@_spi' protection level}}
+  y.YinA()
+
+  x.XinB() // expected-member-visibility-error{{instance method 'XinB()' is not available due to missing import of defining module 'members_B'}}
+  x.XinB_package() // expected-member-visibility-error{{instance method 'XinB_package()' is not available due to missing import of defining module 'members_B'}}
+  x.XinB_spi() // expected-error{{'XinB_spi' is inaccessible due to '@_spi' protection level}}
+  y.YinB() // expected-member-visibility-error{{instance method 'YinB()' is not available due to missing import of defining module 'members_B'}}
+
+  x.XinC()
+  x.XinC_spi() // expected-error{{'XinC_spi' is inaccessible due to '@_spi' protection level}}
+  y.YinC()
+
+  _ = X(true)
+  _ = X(1) // expected-member-visibility-error{{initializer 'init(_:)' is not available due to missing import of defining module 'members_B'}}
+
+  _ = x.ambiguous() // expected-ambiguity-error{{ambiguous use of 'ambiguous()'}}
+  let _: Bool = x.ambiguous()
+  let _: Int = x.ambiguous() // expected-member-visibility-error{{instance method 'ambiguous()' is not available due to missing import of defining module 'members_B'}}
+
+  // ambiguousDisfavored() has two overloads:
+  // - members_B: public func ambiguousDisfavored() -> Int
+  // - members_C: @_disfavoredOverload public func ambiguousDisfavored() -> Bool
+  // With MemberImportVisibility, the overload from members_C should be picked.
+  // Otherwise, the overload from members_B should be picked.
+  let disfavoredResult = x.ambiguousDisfavored()
+  let _: Bool = disfavoredResult // expected-ambiguity-error{{type 'Int' cannot be used as a boolean; test for '!= 0' instead}}
+  let _: Int = disfavoredResult // expected-member-visibility-error{{cannot convert value of type 'Bool' to specified type 'Int'}}
+  let _: Bool = x.ambiguousDisfavored()
+  let _: Int = x.ambiguousDisfavored() // expected-member-visibility-error{{instance method 'ambiguousDisfavored()' is not available due to missing import of defining module 'members_B'}}
+
+  func takesKeyPath<T, U>(_ t: T, _ keyPath: KeyPath<T, U>) -> () { }
+
+  takesKeyPath(x, \.propXinA)
+  takesKeyPath(x, \.propXinB) // expected-member-visibility-warning{{property 'propXinB' is not available due to missing import of defining module 'members_B'}}
+  takesKeyPath(x, \.propXinC)
+
+  takesKeyPath(x, \.propXinA.description)
+  takesKeyPath(x, \.propXinB.description) // expected-member-visibility-warning{{property 'propXinB' is not available due to missing import of defining module 'members_B'}}
+  takesKeyPath(x, \.propXinC.description)
+}
+
+func testOperatorMembers(x: X, y: Y<Z>) {
+  _ = x <<< x
+  _ = y <<< y
+
+  _ = x >>> x // expected-error{{cannot find operator '>>>' in scope}}
+  _ = y >>> y // expected-error{{cannot find operator '>>>' in scope}}
+
+  _ = x <> x
+  _ = y <> y
+}
+
+struct GenericType<T> { }
+
+extension X {
+  var testPropertyInA: Bool { propXinA }
+  var testPropertyInB: Bool { propXinB } // expected-member-visibility-error {{property 'propXinB' is not available due to missing import of defining module 'members_B'}}
+  var testPropertyInB_package: Bool { propXinB_package } // expected-member-visibility-error{{property 'propXinB_package' is not available due to missing import of defining module 'members_B}}
+  var testPropertyInC: Bool { propXinC }
+
+  // This is not diagnosed in either mode (the property from the nearest scope is always preferred
+  var testAmbiguousProp: Bool { ambiguousProp }
+
+  func testTypeExpressions() {
+    _ = NestedInA.self
+    _ = NestedInB.self // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
+    _ = NestedInB_package.self // expected-member-visibility-error{{struct 'NestedInB_package' is not available due to missing import of defining module 'members_B'}}
+    _ = (NestedInB).self // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
+    _ = (NestedInA, NestedInB, NestedInC).self // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
+    _ = GenericType<NestedInB>.self // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
+    _ = NestedInC.self
+    _ = AmbiguousNestedType.self
+  }
+
+  var hasNestedInAType: NestedInA { fatalError() }
+  var hasNestedInBType: NestedInB { fatalError() } // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
+  var hasNestedInB_packageType: NestedInB_package { fatalError() } // expected-member-visibility-error{{struct 'NestedInB_package' is not available due to missing import of defining module 'members_B'}}
+  var hasNestedInBTrivialTupleType: (NestedInB) { fatalError() } // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
+  var hasTupleTypeContainingNestedInB: (NestedInA, NestedInB, NestedInC) { fatalError() } // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
+  var hasNestedInBAsGenericTypeParameter: GenericType<NestedInB> { fatalError() } // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
+  var hasNestedInCType: NestedInC { fatalError() }
+
+  func hasNestedInAInGenericReqs<T>(_ t: T) where T: ProtoNestedInA { }
+  func hasNestedInBInGenericReqs<T>(_ t: T) where T: ProtoNestedInB { } // expected-member-visibility-error{{protocol 'ProtoNestedInB' is not available due to missing import of defining module 'members_B'}}
+  func hasNestedInCInGenericReqs<T>(_ t: T) where T: ProtoNestedInC { }
+
+  func testMembersShadowingGlobals() {
+    shadowedByMemberOnXinA()
+    shadowedByMemberOnXinB() // expected-member-visibility-warning{{'shadowedByMemberOnXinB()' is deprecated}}
+    shadowedByMemberOnXinC()
+
+    _ = max(0, 1) // expected-ambiguity-error{{static member 'max' cannot be used on instance of type 'X'}}
+    // expected-ambiguity-error@-1{{cannot call value of non-function type 'Int'}}
+  }
+
+  static func testStaticMembersShadowingGlobals() {
+    shadowedByStaticMemberOnXinA()
+    shadowedByStaticMemberOnXinB() // expected-member-visibility-warning{{'shadowedByStaticMemberOnXinB()' is deprecated}}
+    shadowedByStaticMemberOnXinC()
+
+    _ = max(0, 1) // expected-ambiguity-error{{use of 'max' refers to instance method rather than global function 'max' in module 'Swift'}}
+    // expected-ambiguity-note@-1{{use 'Swift.' to reference the global function in module 'Swift'}}
+  }
+}
+
+extension X.NestedInA {}
+extension X.NestedInB {} // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
+extension X.NestedInB_package {} // expected-member-visibility-error{{struct 'NestedInB_package' is not available due to missing import of defining module 'members_B'}}
+extension X.NestedInC {}
+
+func testTypeExpressionsReferencingTopLevelTypes() {
+  _ = EnumInA.self
+  _ = EnumInB.self // expected-error{{cannot find 'EnumInB' in scope}}
+  _ = EnumInB_package.self // expected-error{{cannot find 'EnumInB_package' in scope}}
+  _ = EnumInC.self
+}
+
+class DerivedFromClassInC: DerivedClassInC {
+  override func methodInA() {}
+  override func methodInB() {} // expected-member-visibility-error{{instance method 'methodInB()' is not available due to missing import of defining module 'members_B'}}
+  override func methodInC() {}
+}
+
+// FIXME: Visibility of defaultedRequirementInB() should be diagnosed (rdar://154237873)
+struct ConformsToProtocolInA: ProtocolInA {} // expected-member-visibility-error{{type 'ConformsToProtocolInA' does not conform to protocol 'ProtocolInA'}} expected-member-visibility-note {{add stubs for conformance}}{{44-44=\n    func defaultedRequirementInB() {\n        <#code#>\n    \}\n}}
+
+func testInheritedMethods(
+  a: BaseClassInA,
+  c: DerivedClassInC,
+) {
+  let b = c.asDerivedClassInB()
+
+  a.methodInA()
+  b.methodInA()
+  c.methodInA()
+
+  b.methodInB() // expected-member-visibility-error{{instance method 'methodInB()' is not available due to missing import of defining module 'members_B'}}
+  c.methodInB() // expected-member-visibility-error{{instance method 'methodInB()' is not available due to missing import of defining module 'members_B'}}
+
+  c.methodInC()
+
+  a.overriddenMethod()
+  b.overriddenMethod() // expected-member-visibility-error{{instance method 'overriddenMethod()' is not available due to missing import of defining module 'members_B'}}
+  c.overriddenMethod()
+}
+
+func testLeadingDotSyntax() {
+  func takesP<T: P>(_: T) { }
+  takesP(.zInA)
+  takesP(.zInB) // expected-member-visibility-error{{static property 'zInB' is not available due to missing import of defining module 'members_B'}}
+  takesP(.zInC)
+  takesP(.zAmbiguous)
+}
diff --git a/test/NameLookup/member_import_visibility_compiler_protocols.swift b/test/NameLookup/member_import_visibility_compiler_protocols.swift
new file mode 100644
index 0000000000000..989fac5d95a2d
--- /dev/null
+++ b/test/NameLookup/member_import_visibility_compiler_protocols.swift
@@ -0,0 +1,149 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module -o %t %t/lib.swift
+// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %t/other.swift -I %t -verify -enable-upcoming-feature MemberImportVisibility
+
+// REQUIRES: swift_feature_MemberImportVisibility
+
+//--- main.swift
+
+import Swift
+// expected-note 15 {{add import of module 'lib'}}
+
+for _ in makeSequence() { }
+// expected-error@-1 {{instance method 'makeIterator()' is not available due to missing import of defining module 'lib'}}
+// expected-error@-2 {{instance method 'next()' is not available due to missing import of defining module 'lib'}}
+
+takesNilExpressible(nil)
+// expected-error@-1 {{initializer 'init(nilLiteral:)' is not available due to missing import of defining module 'lib'}}
+
+takesIntExpressible(1)
+// expected-error@-1 {{initializer 'init(integerLiteral:)' is not available due to missing import of defining module 'lib'}}
+
+takesFloatExpressible(1.0)
+// expected-error@-1 {{initializer 'init(floatLiteral:)' is not available due to missing import of defining module 'lib'}}
+
+takesBoolExpressible(true)
+// expected-error@-1 {{initializer 'init(booleanLiteral:)' is not available due to missing import of defining module 'lib'}}
+
+takesUnicodeScalarExpressible("🐦")
+// expected-error@-1 {{initializer 'init(unicodeScalarLiteral:)' is not available due to missing import of defining module 'lib'}}
+
+takesExtendedGraphemeClusterExpressible("🦸🏾‍♀️")
+// expected-error@-1 {{initializer 'init(extendedGraphemeClusterLiteral:)' is not available due to missing import of defining module 'lib'}}
+
+takesStringLiteralExpressible("Hello world")
+// expected-error@-1 {{initializer 'init(stringLiteral:)' is not available due to missing import of defining module 'lib'}}
+
+takesArrayExpressible([1])
+// expected-error@-1 {{initializer 'init(arrayLiteral:)' is not available due to missing import of defining module 'lib'}}
+
+takesDictionaryExpressible(["one": 1])
+// expected-error@-1 {{initializer 'init(dictionaryLiteral:)' is not available due to missing import of defining module 'lib'}}
+
+takesMessage("\(1)")
+// expected-error@-1 {{initializer 'init(stringInterpolation:)' is not available due to missing import of defining module 'lib'}}
+// expected-error@-2 {{instance method 'appendInterpolation' is not available due to missing import of defining module 'lib'}}
+// expected-error@-3 2 {{instance method 'appendLiteral' is not available due to missing import of defining module 'lib'}}
+
+takesColorExpressible(#colorLiteral(red: 0.0, green: 0.0, blue: 0.0, alpha: 1))
+// FIXME: Missing diangostic
+
+takesImageExpressible(#imageLiteral(resourceName: "image.png"))
+// FIXME: Missing diangostic
+
+takesFileReferenceExpressible(#fileLiteral(resourceName: "file.txt"))
+// FIXME: Missing diangostic
+
+//--- other.swift
+
+import lib
+
+func makeSequence() -> EmptySequence {
+  return MySequence()
+}
+
+func takesNilExpressible(_ x: NilExpressible) { }
+func takesIntExpressible(_ x: IntExpressible) { }
+func takesFloatExpressible(_ x: FloatExpressible) { }
+func takesBoolExpressible(_ x: BoolExpressible) { }
+func takesUnicodeScalarExpressible(_ x: UnicodeScalarExpressible) { }
+func takesExtendedGraphemeClusterExpressible(_ x: ExtendedGraphemeClusterExpressible) { }
+func takesStringLiteralExpressible(_ x: StringExpressible) { }
+func takesArrayExpressible<E>(_ x: ArrayExpressible<E>) { }
+func takesDictionaryExpressible<K, V>(_ x: DictionaryExpressible<K, V>) { }
+func takesMessage(_ x: Message) { }
+func takesColorExpressible(_ x: ColorExpressible) { }
+func takesImageExpressible(_ x: ImageExpressible) { }
+func takesFileReferenceExpressible(_ x: FileReferenceExpressible) { }
+
+//--- lib.swift
+
+public struct EmptySequence: Sequence {
+  public struct Iterator: IteratorProtocol {
+    public mutating func next() -> Int? { nil }
+  }
+
+  public func makeIterator() -> Iterator { Iterator() }
+  public init() { }
+}
+
+public struct NilExpressible: ExpressibleByNilLiteral {
+  public init(nilLiteral: ()) { }
+}
+
+public struct IntExpressible: ExpressibleByIntegerLiteral {
+  public init(integerLiteral value: Int) { }
+}
+
+public struct FloatExpressible: ExpressibleByFloatLiteral {
+  public init(floatLiteral value: Float) { }
+}
+
+public struct BoolExpressible: ExpressibleByBooleanLiteral {
+  public init(booleanLiteral value: Bool) { }
+}
+
+public struct UnicodeScalarExpressible: ExpressibleByUnicodeScalarLiteral {
+  public init(unicodeScalarLiteral value: Unicode.Scalar) { }
+}
+
+public struct ExtendedGraphemeClusterExpressible: ExpressibleByExtendedGraphemeClusterLiteral {
+  public init(extendedGraphemeClusterLiteral value: Character) { }
+}
+
+public struct StringExpressible: ExpressibleByStringLiteral {
+  public init(stringLiteral value: String) { }
+}
+
+public struct ArrayExpressible<Element>: ExpressibleByArrayLiteral {
+  public init(arrayLiteral elements: Element...) { }
+}
+
+public struct DictionaryExpressible<Key, Value>: ExpressibleByDictionaryLiteral {
+  public init(dictionaryLiteral elements: (Key, Value)...) { }
+}
+
+public struct MessageInterpolation: StringInterpolationProtocol {
+  public init(literalCapacity: Int, interpolationCount: Int) { }
+  public mutating func appendInterpolation(_ value: @autoclosure () -> Int) { }
+  public mutating func appendLiteral(_ literal: String) { }
+}
+
+public struct Message: ExpressibleByStringInterpolation {
+  public init(stringInterpolation: MessageInterpolation) { }
+  public init(stringLiteral: String) { }
+}
+
+public struct ColorExpressible: _ExpressibleByColorLiteral {
+  public init(_colorLiteralRed red: Float, green: Float, blue: Float, alpha: Float) { }
+}
+
+public struct ImageExpressible: _ExpressibleByImageLiteral {
+  public init(imageLiteralResourceName path: String) { }
+}
+
+public struct FileReferenceExpressible: _ExpressibleByFileReferenceLiteral {
+  public init(fileReferenceLiteralResourceName path: String) { }
+}
diff --git a/test/NameLookup/member_import_visibility_migrate.swift b/test/NameLookup/member_import_visibility_migrate.swift
new file mode 100644
index 0000000000000..237080e10df90
--- /dev/null
+++ b/test/NameLookup/member_import_visibility_migrate.swift
@@ -0,0 +1,206 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnly.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyDefaultedImport.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/PackageUsesOnly.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/PublicUsesOnly.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/PublicUsesOnlyDefaultedImport.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/MixedUses.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyReexported.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyTransitivelyImported.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/ImportsOtherModules.swift -I %t
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlySPIOnly.swift -I %t
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyDefaultedImportSPIOnly.swift -I %t
+// RUN: %target-swift-frontend -emit-module -o %t %t/PublicUsesOnlySPIOnly.swift -I %t
+
+// RUN: %target-swift-frontend -emit-silgen -verify -swift-version 5 \
+// RUN:   -primary-file %t/main.swift \
+// RUN:   %t/imports.swift \
+// RUN:   -I %t -package-name Package \
+// RUN:   -enable-upcoming-feature MemberImportVisibility:migrate
+
+// REQUIRES: swift_feature_MemberImportVisibility
+
+//--- main.swift
+
+// FIXME: The access level on the fix-it for PackageUsesOnly is wrong.
+import Swift // Just here to anchor the fix-its
+// expected-warning      {{import of module 'InternalUsesOnly' is required}}{{1-1=internal import InternalUsesOnly\n}}
+// expected-warning@-1   {{import of module 'InternalUsesOnlyDefaultedImport' is required}}{{1-1=import InternalUsesOnlyDefaultedImport\n}}
+// expected-warning@-2   {{import of module 'PackageUsesOnly' is required}}{{1-1=public import PackageUsesOnly\n}}
+// expected-warning@-3   {{import of module 'PublicUsesOnly' is required}}{{1-1=public import PublicUsesOnly\n}}
+// expected-warning@-4   {{import of module 'PublicUsesOnlyDefaultedImport' is required}}{{1-1=import PublicUsesOnlyDefaultedImport\n}}
+// expected-warning@-5   {{import of module 'MixedUses' is required}}{{1-1=public import MixedUses\n}}
+// expected-warning@-6   {{import of module 'InternalUsesOnlyReexported' is required}}{{1-1=internal import InternalUsesOnlyReexported\n}}
+// expected-warning@-7   {{import of module 'InternalUsesOnlyTransitivelyImported' is required}}{{1-1=internal import InternalUsesOnlyTransitivelyImported\n}}
+// expected-warning@-8   {{import of module 'InternalUsesOnlySPIOnly' is required}}{{1-1=internal import InternalUsesOnlySPIOnly\n}}
+// expected-warning@-9   {{import of module 'InternalUsesOnlyDefaultedImportSPIOnly' is required}}{{1-1=@_spiOnly import InternalUsesOnlyDefaultedImportSPIOnly\n}}
+// expected-warning@-10  {{import of module 'PublicUsesOnlySPIOnly' is required}}{{1-1=@_spiOnly public import PublicUsesOnlySPIOnly\n}}
+
+func internalFunc(_ x: Int) {
+  _ = x.memberInInternalUsesOnly // expected-note {{property 'memberInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+  _ = x.memberInInternalUsesOnlyDefaultedImport // expected-note {{property 'memberInInternalUsesOnlyDefaultedImport' from 'InternalUsesOnlyDefaultedImport' used here}}
+  _ = x.memberInMixedUses // expected-note {{property 'memberInMixedUses' from 'MixedUses' used here}}
+  _ = x.memberInInternalUsesOnlyReexported // expected-note {{property 'memberInInternalUsesOnlyReexported' from 'InternalUsesOnlyReexported' used here}}
+  _ = x.memberInInternalUsesOnlySPIOnly // expected-note {{property 'memberInInternalUsesOnlySPIOnly' from 'InternalUsesOnlySPIOnly' used here}}
+  _ = x.memberInInternalUsesOnlyDefaultedImportSPIOnly // expected-note {{property 'memberInInternalUsesOnlyDefaultedImportSPIOnly' from 'InternalUsesOnlyDefaultedImportSPIOnly' used here}}
+  _ = x.memberInInternalUsesOnlyTransitivelyImported // expected-note {{property 'memberInInternalUsesOnlyTransitivelyImported' from 'InternalUsesOnlyTransitivelyImported' used here}}
+}
+
+func keyPaths(_ x: Int) {
+  func takesKeyPath<T, U>(_ t: T, _ keyPath: KeyPath<T, U>) -> () { }
+
+  takesKeyPath(x, \.memberInInternalUsesOnly) // expected-note {{property 'memberInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+  takesKeyPath(x, \.memberInInternalUsesOnlyDefaultedImport) // expected-note {{property 'memberInInternalUsesOnlyDefaultedImport' from 'InternalUsesOnlyDefaultedImport' used here}}
+  takesKeyPath(x, \.memberInMixedUses) // expected-note {{property 'memberInMixedUses' from 'MixedUses' used here}}
+  takesKeyPath(x, \.memberInInternalUsesOnlyReexported) // expected-note {{property 'memberInInternalUsesOnlyReexported' from 'InternalUsesOnlyReexported' used here}}
+  takesKeyPath(x, \.memberInInternalUsesOnlySPIOnly) // expected-note {{property 'memberInInternalUsesOnlySPIOnly' from 'InternalUsesOnlySPIOnly' used here}}
+  takesKeyPath(x, \.memberInInternalUsesOnlyDefaultedImportSPIOnly) // expected-note {{property 'memberInInternalUsesOnlyDefaultedImportSPIOnly' from 'InternalUsesOnlyDefaultedImportSPIOnly' used here}}
+  takesKeyPath(x, \.memberInInternalUsesOnlyTransitivelyImported) // expected-note {{property 'memberInInternalUsesOnlyTransitivelyImported' from 'InternalUsesOnlyTransitivelyImported' used here}}
+}
+
+@inlinable package func packageInlinableFunc(_ x: Int) {
+  _ = x.memberInPackageUsesOnly // expected-note {{property 'memberInPackageUsesOnly' from 'PackageUsesOnly' used here}}
+  _ = x.memberInMixedUses // expected-note {{property 'memberInMixedUses' from 'MixedUses' used here}}
+}
+
+@inlinable public func inlinableFunc(_ x: Int) {
+  _ = x.memberInPublicUsesOnly // expected-note {{property 'memberInPublicUsesOnly' from 'PublicUsesOnly' used here}}
+  _ = x.memberInPublicUsesOnlyDefaultedImport // expected-note {{property 'memberInPublicUsesOnlyDefaultedImport' from 'PublicUsesOnlyDefaultedImport' used here}}
+  _ = x.memberInMixedUses // expected-note {{property 'memberInMixedUses' from 'MixedUses' used here}}
+  _ = x.memberInPublicUsesOnlySPIOnly // expected-note {{property 'memberInPublicUsesOnlySPIOnly' from 'PublicUsesOnlySPIOnly' used here}}
+}
+
+extension Int {
+  private func usesTypealiasInInternalUsesOnly_Private(x: TypealiasInInternalUsesOnly) {} // expected-note {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+  internal func usesTypealiasInInternalUsesOnly(x: TypealiasInInternalUsesOnly) {} // expected-note {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+  package func usesTypealiasInPackageUsesOnly(x: TypealiasInPackageUsesOnly) {} // expected-note {{type alias 'TypealiasInPackageUsesOnly' from 'PackageUsesOnly' used here}}
+  public func usesTypealiasInPublicUsesOnly(x: TypealiasInPublicUsesOnly) {} // expected-note {{type alias 'TypealiasInPublicUsesOnly' from 'PublicUsesOnly' used here}}
+  public func usesTypealiasInMixedUses(x: TypealiasInMixedUses) {} // expected-note {{type alias 'TypealiasInMixedUses' from 'MixedUses' used here}}
+  internal func usesTypealiasInMixedUses_Internal(x: TypealiasInMixedUses) {} // expected-note {{type alias 'TypealiasInMixedUses' from 'MixedUses' used here}}
+}
+
+struct GenericType<T> { }
+
+extension Int {
+  var referencesMemberInInternalUsesOnly: Int { memberInInternalUsesOnly } // expected-note {{property 'memberInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+
+  func testTypes<T: ProtocolInInternalUsesOnly>(_ t: T) -> TypealiasInInternalUsesOnly? {
+    // expected-note@-1 {{protocol 'ProtocolInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+    // expected-note@-2 {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+
+    let _: TypealiasInInternalUsesOnly = 0 // expected-note {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+    _ = TypealiasInInternalUsesOnly.self // expected-note {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+    _ = (TypealiasInInternalUsesOnly).self // expected-note {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+    _ = (Int, TypealiasInInternalUsesOnly).self // expected-note {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+    _ = GenericType<TypealiasInInternalUsesOnly>.self // expected-note {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+    return t as? TypealiasInInternalUsesOnly // expected-note {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+  }
+
+  func testLeadingDotSyntax() {
+    func takesP<T: ProtocolInInternalUsesOnly>(_: T) { } // expected-note {{protocol 'ProtocolInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+    takesP(.staticDefaultMemberInInternalUsesOnly) // expected-note {{static property 'staticDefaultMemberInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+  }
+}
+
+extension Int.TypealiasInInternalUsesOnly { } // expected-note {{type alias 'TypealiasInInternalUsesOnly' from 'InternalUsesOnly' used here}}
+
+//--- imports.swift
+
+internal import InternalUsesOnly
+import InternalUsesOnlyDefaultedImport
+internal import PackageUsesOnly
+internal import PublicUsesOnly
+import PublicUsesOnlyDefaultedImport
+internal import MixedUses
+internal import ImportsOtherModules
+@_spiOnly public import InternalUsesOnlySPIOnly
+@_spiOnly import InternalUsesOnlyDefaultedImportSPIOnly
+@_spiOnly public import PublicUsesOnlySPIOnly
+
+//--- InternalUsesOnly.swift
+
+extension Int {
+  public protocol ProtocolInInternalUsesOnly { }
+  public typealias TypealiasInInternalUsesOnly = Self
+  public var memberInInternalUsesOnly: Int { return self }
+}
+
+extension Int: Int.ProtocolInInternalUsesOnly { }
+
+extension Int.ProtocolInInternalUsesOnly where Self == Int {
+  public static var staticDefaultMemberInInternalUsesOnly: Int { 0 }
+}
+
+//--- InternalUsesOnlyDefaultedImport.swift
+
+extension Int {
+  public typealias TypealiasInInternalUsesOnlyDefaultedImport = Self
+  public var memberInInternalUsesOnlyDefaultedImport: Int { return self }
+}
+
+//--- PackageUsesOnly.swift
+
+extension Int {
+  public typealias TypealiasInPackageUsesOnly = Self
+  public var memberInPackageUsesOnly: Int { return self }
+}
+
+//--- PublicUsesOnly.swift
+
+extension Int {
+  public typealias TypealiasInPublicUsesOnly = Self
+  public var memberInPublicUsesOnly: Int { return self }
+}
+
+//--- PublicUsesOnlyDefaultedImport.swift
+
+extension Int {
+  public typealias TypealiasInPublicUsesOnlyDefaultedImport = Self
+  public var memberInPublicUsesOnlyDefaultedImport: Int { return self }
+}
+
+//--- MixedUses.swift
+
+extension Int {
+  public typealias TypealiasInMixedUses = Self
+  public var memberInMixedUses: Int { return self }
+}
+
+//--- InternalUsesOnlyReexported.swift
+
+extension Int {
+  public typealias TypealiasInInternalUsesOnlyReexported = Self
+  public var memberInInternalUsesOnlyReexported: Int { return self }
+}
+
+//--- InternalUsesOnlyTransitivelyImported.swift
+
+extension Int {
+  public typealias TypealiasInInternalUsesOnlyTransitivelyImported = Self
+  public var memberInInternalUsesOnlyTransitivelyImported: Int { return self }
+}
+
+//--- ImportsOtherModules.swift
+
+@_exported import InternalUsesOnlyReexported
+import InternalUsesOnlyTransitivelyImported
+
+//--- InternalUsesOnlySPIOnly.swift
+
+extension Int {
+  public var memberInInternalUsesOnlySPIOnly: Int { return self }
+}
+
+//--- InternalUsesOnlyDefaultedImportSPIOnly.swift
+
+extension Int {
+  public var memberInInternalUsesOnlyDefaultedImportSPIOnly: Int { return self }
+}
+
+//--- PublicUsesOnlySPIOnly.swift
+
+extension Int {
+  public var memberInPublicUsesOnlySPIOnly: Int { return self }
+}
diff --git a/test/NameLookup/member_import_visibility_multifile.swift b/test/NameLookup/member_import_visibility_multifile.swift
new file mode 100644
index 0000000000000..1e5b873bbd4c6
--- /dev/null
+++ b/test/NameLookup/member_import_visibility_multifile.swift
@@ -0,0 +1,44 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/MemberImportVisibility/members_A.swift
+// RUN: %target-swift-frontend -emit-module -I %t -o %t -package-name TestPackage %S/Inputs/MemberImportVisibility/members_B.swift
+// RUN: %target-swift-frontend -emit-module -I %t -o %t %S/Inputs/MemberImportVisibility/members_C.swift
+// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %t/A.swift %t/B.swift %t/C.swift -I %t -verify -verify-ignore-unrelated -swift-version 5
+// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %t/A.swift %t/B.swift %t/C.swift -I %t -verify -verify-ignore-unrelated -swift-version 6
+// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %t/A.swift %t/B.swift %t/C.swift -I %t -verify -verify-ignore-unrelated -swift-version 5 -enable-upcoming-feature MemberImportVisibility -verify-additional-prefix member-visibility-
+
+// REQUIRES: swift_feature_MemberImportVisibility
+
+//--- main.swift
+
+// expected-member-visibility-note@+2 {{add import of module 'members_A'}}{{1-1=@_implementationOnly import members_A\n}}
+// expected-member-visibility-note@+1 {{add import of module 'members_C'}}{{1-1=@_weakLinked @_spiOnly import members_C\n}}
+func testMembersWithInferredContextualBase() {
+  takesEnumInA(.caseInA) // expected-member-visibility-error{{enum case 'caseInA' is not available due to missing import of defining module 'members_A'}}
+  takesEnumInB(.caseInB)
+  takesEnumInC(.caseInC) // expected-member-visibility-error{{enum case 'caseInC' is not available due to missing import of defining module 'members_C'}}
+}
+
+func testQualifiedMembers() {
+  takesEnumInA(EnumInA.caseInA) // expected-error{{cannot find 'EnumInA' in scope; did you mean 'EnumInB'?}}
+  takesEnumInB(EnumInB.caseInB)
+  takesEnumInC(EnumInC.caseInC) // expected-error{{cannot find 'EnumInC' in scope; did you mean 'EnumInB'?}}
+}
+
+//--- A.swift
+
+@_implementationOnly import members_A
+
+func takesEnumInA(_ e: EnumInA) {}
+
+//--- B.swift
+
+@_exported import members_B
+
+func takesEnumInB(_ e: EnumInB) {}
+
+//--- C.swift
+
+@_spiOnly @_weakLinked import members_C
+
+func takesEnumInC(_ e: EnumInC) {}
diff --git a/test/NameLookup/member_import_visibility_multifile_access_level.swift b/test/NameLookup/member_import_visibility_multifile_access_level.swift
new file mode 100644
index 0000000000000..6825da6f114fb
--- /dev/null
+++ b/test/NameLookup/member_import_visibility_multifile_access_level.swift
@@ -0,0 +1,243 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnly.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyDefaultedImport.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/PackageUsesOnly.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/PublicUsesOnly.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/PublicUsesOnlyDefaultedImport.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/MixedUses.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyReexported.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyTransitivelyImported.swift
+// RUN: %target-swift-frontend -emit-module -o %t %t/ImportsOtherModules.swift -I %t
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlySPIOnly.swift -I %t
+// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyDefaultedImportSPIOnly.swift -I %t
+// RUN: %target-swift-frontend -emit-module -o %t %t/PublicUsesOnlySPIOnly.swift -I %t
+
+// RUN: %target-swift-frontend -typecheck -verify -swift-version 5 \
+// RUN:   -primary-file %t/function_bodies.swift \
+// RUN:   -primary-file %t/function_signatures_unqualified.swift \
+// RUN:   -primary-file %t/function_signatures_qualified.swift \
+// RUN:   -primary-file %t/extensions.swift \
+// RUN:   %t/imports.swift \
+// RUN:   -I %t -package-name Package \
+// RUN:   -enable-upcoming-feature MemberImportVisibility \
+// RUN:   -verify-additional-prefix public-by-default-
+
+// RUN: %target-swift-frontend -typecheck -verify -swift-version 5 \
+// RUN:   -primary-file %t/function_bodies.swift \
+// RUN:   -primary-file %t/function_signatures_unqualified.swift \
+// RUN:   -primary-file %t/function_signatures_qualified.swift \
+// RUN:   -primary-file %t/extensions.swift \
+// RUN:   %t/imports.swift \
+// RUN:   -I %t -package-name Package \
+// RUN:   -enable-upcoming-feature MemberImportVisibility \
+// RUN:   -enable-upcoming-feature InternalImportsByDefault \
+// RUN:   -verify-additional-prefix internal-by-default-
+
+// REQUIRES: swift_feature_InternalImportsByDefault
+// REQUIRES: swift_feature_MemberImportVisibility
+
+//--- function_bodies.swift
+
+// FIXME: The access level on the fix-it for PackageUsesOnly is wrong.
+import Swift // Just here to anchor the fix-its
+// expected-note      {{add import of module 'InternalUsesOnly'}}{{1-1=internal import InternalUsesOnly\n}}
+// expected-note@-1   {{add import of module 'InternalUsesOnlyDefaultedImport'}}{{1-1=import InternalUsesOnlyDefaultedImport\n}}
+// expected-note@-2   {{add import of module 'PackageUsesOnly'}}{{1-1=public import PackageUsesOnly\n}}
+// expected-note@-3   {{add import of module 'PublicUsesOnly'}}{{1-1=public import PublicUsesOnly\n}}
+// expected-note@-4   {{add import of module 'PublicUsesOnlyDefaultedImport'}}{{1-1=import PublicUsesOnlyDefaultedImport\n}}
+// expected-note@-5 3 {{add import of module 'MixedUses'}}{{1-1=public import MixedUses\n}}
+// expected-public-by-default-note@-6   {{add import of module 'InternalUsesOnlyReexported'}}{{1-1=internal import InternalUsesOnlyReexported\n}}
+// expected-internal-by-default-note@-7   {{add import of module 'InternalUsesOnlyReexported'}}{{1-1=import InternalUsesOnlyReexported\n}}
+// expected-public-by-default-note@-8   {{add import of module 'InternalUsesOnlyTransitivelyImported'}}{{1-1=internal import InternalUsesOnlyTransitivelyImported\n}}
+// expected-internal-by-default-note@-9   {{add import of module 'InternalUsesOnlyTransitivelyImported'}}{{1-1=import InternalUsesOnlyTransitivelyImported\n}}
+// expected-note@-10   {{add import of module 'InternalUsesOnlySPIOnly'}}{{1-1=internal import InternalUsesOnlySPIOnly\n}}
+// expected-public-by-default-note@-11     {{add import of module 'InternalUsesOnlyDefaultedImportSPIOnly'}}{{1-1=@_spiOnly import InternalUsesOnlyDefaultedImportSPIOnly\n}}
+// expected-internal-by-default-note@-12   {{add import of module 'InternalUsesOnlyDefaultedImportSPIOnly'}}{{1-1=import InternalUsesOnlyDefaultedImportSPIOnly\n}}
+// expected-note@-13  {{add import of module 'PublicUsesOnlySPIOnly'}}{{1-1=@_spiOnly public import PublicUsesOnlySPIOnly\n}}
+
+func internalFunc(_ x: Int) {
+  _ = x.memberInInternalUsesOnly // expected-error {{property 'memberInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
+  _ = x.memberInInternalUsesOnlyDefaultedImport // expected-error {{property 'memberInInternalUsesOnlyDefaultedImport' is not available due to missing import of defining module 'InternalUsesOnlyDefaultedImport'}}
+  _ = x.memberInMixedUses // expected-error {{property 'memberInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
+  _ = x.memberInInternalUsesOnlyReexported // expected-error {{property 'memberInInternalUsesOnlyReexported' is not available due to missing import of defining module 'InternalUsesOnlyReexported'}}
+  _ = x.memberInInternalUsesOnlySPIOnly // expected-error {{property 'memberInInternalUsesOnlySPIOnly' is not available due to missing import of defining module 'InternalUsesOnlySPIOnly'}}
+  _ = x.memberInInternalUsesOnlyDefaultedImportSPIOnly // expected-error {{property 'memberInInternalUsesOnlyDefaultedImportSPIOnly' is not available due to missing import of defining module 'InternalUsesOnlyDefaultedImportSPIOnly'}}
+  _ = x.memberInInternalUsesOnlyTransitivelyImported // expected-error {{property 'memberInInternalUsesOnlyTransitivelyImported' is not available due to missing import of defining module 'InternalUsesOnlyTransitivelyImported'}}
+}
+
+@inlinable package func packageInlinableFunc(_ x: Int) {
+  _ = x.memberInPackageUsesOnly // expected-error {{property 'memberInPackageUsesOnly' is not available due to missing import of defining module 'PackageUsesOnly'}}
+  _ = x.memberInMixedUses // expected-error {{property 'memberInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
+}
+
+@inlinable public func inlinableFunc(_ x: Int) {
+  _ = x.memberInPublicUsesOnly // expected-error {{property 'memberInPublicUsesOnly' is not available due to missing import of defining module 'PublicUsesOnly'}}
+  _ = x.memberInPublicUsesOnlyDefaultedImport // expected-error {{property 'memberInPublicUsesOnlyDefaultedImport' is not available due to missing import of defining module 'PublicUsesOnlyDefaultedImport'}}
+  _ = x.memberInMixedUses // expected-error {{property 'memberInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
+  _ = x.memberInPublicUsesOnlySPIOnly // expected-error {{property 'memberInPublicUsesOnlySPIOnly' is not available due to missing import of defining module 'PublicUsesOnlySPIOnly'}}
+}
+
+//--- function_signatures_unqualified.swift
+
+import Swift // Just here to anchor the fix-its
+// expected-note    2 {{add import of module 'InternalUsesOnly'}}{{1-1=internal import InternalUsesOnly\n}}
+// expected-note@-1   {{add import of module 'PackageUsesOnly'}}{{1-1=package import PackageUsesOnly\n}}
+// expected-note@-2   {{add import of module 'PublicUsesOnly'}}{{1-1=public import PublicUsesOnly\n}}
+// expected-note@-3 2 {{add import of module 'MixedUses'}}{{1-1=public import MixedUses\n}}
+
+extension Int {
+  private func usesTypealiasInInternalUsesOnly_Private(x: TypealiasInInternalUsesOnly) {} // expected-error {{type alias 'TypealiasInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
+  internal func usesTypealiasInInternalUsesOnly(x: TypealiasInInternalUsesOnly) {} // expected-error {{type alias 'TypealiasInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
+  package func usesTypealiasInPackageUsesOnly(x: TypealiasInPackageUsesOnly) {} // expected-error {{type alias 'TypealiasInPackageUsesOnly' is not available due to missing import of defining module 'PackageUsesOnly'}}
+  public func usesTypealiasInPublicUsesOnly(x: TypealiasInPublicUsesOnly) {} // expected-error {{type alias 'TypealiasInPublicUsesOnly' is not available due to missing import of defining module 'PublicUsesOnly'}}
+  public func usesTypealiasInMixedUses(x: TypealiasInMixedUses) {} // expected-error {{type alias 'TypealiasInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
+  internal func usesTypealiasInMixedUses_Internal(x: TypealiasInMixedUses) {} // expected-error {{type alias 'TypealiasInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
+}
+
+//--- function_signatures_qualified.swift
+
+import Swift // Just here to anchor the fix-its
+// expected-note    2 {{add import of module 'InternalUsesOnly'}}{{1-1=internal import InternalUsesOnly\n}}
+// expected-note@-1   {{add import of module 'PackageUsesOnly'}}{{1-1=package import PackageUsesOnly\n}}
+// expected-note@-2   {{add import of module 'PublicUsesOnly'}}{{1-1=public import PublicUsesOnly\n}}
+// expected-note@-3 2 {{add import of module 'MixedUses'}}{{1-1=public import MixedUses\n}}
+
+private func usesTypealiasInInternalUsesOnly_Private(x: Int.TypealiasInInternalUsesOnly) {} // expected-error {{type alias 'TypealiasInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
+internal func usesTypealiasInInternalUsesOnly(x: Int.TypealiasInInternalUsesOnly) {} // expected-error {{type alias 'TypealiasInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
+package func usesTypealiasInPackageUsesOnly(x: Int.TypealiasInPackageUsesOnly) {} // expected-error {{type alias 'TypealiasInPackageUsesOnly' is not available due to missing import of defining module 'PackageUsesOnly'}}
+public func usesTypealiasInPublicUsesOnly(x: Int.TypealiasInPublicUsesOnly) {} // expected-error {{type alias 'TypealiasInPublicUsesOnly' is not available due to missing import of defining module 'PublicUsesOnly'}}
+public func usesTypealiasInMixedUses(x: Int.TypealiasInMixedUses) {} // expected-error {{type alias 'TypealiasInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
+internal func usesTypealiasInMixedUses_Internal(x: Int.TypealiasInMixedUses) {} // expected-error {{type alias 'TypealiasInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
+
+//--- extensions.swift
+
+import Swift // Just here to anchor the fix-its
+// expected-note    2 {{add import of module 'InternalUsesOnly'}}{{1-1=internal import InternalUsesOnly\n}}
+// expected-note@-1   {{add import of module 'PackageUsesOnly'}}{{1-1=package import PackageUsesOnly\n}}
+// expected-note@-2   {{add import of module 'PublicUsesOnly'}}{{1-1=public import PublicUsesOnly\n}}
+// expected-note@-3 2 {{add import of module 'MixedUses'}}{{1-1=public import MixedUses\n}}
+
+extension Int.NestedInInternalUsesOnly { // expected-error {{struct 'NestedInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
+  private func privateMethod() {}
+}
+
+extension Int.NestedInInternalUsesOnly { // expected-error {{struct 'NestedInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
+  internal func internalMethod() {}
+}
+
+extension Int.NestedInPackageUsesOnly { // expected-error {{struct 'NestedInPackageUsesOnly' is not available due to missing import of defining module 'PackageUsesOnly'}}
+  package func packageMethod() {}
+}
+
+extension Int.NestedInPublicUsesOnly { // expected-error {{struct 'NestedInPublicUsesOnly' is not available due to missing import of defining module 'PublicUsesOnly'}}
+  public func publicMethod() {}
+}
+
+extension Int.NestedInMixedUses { // expected-error {{struct 'NestedInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
+  public func publicMethod() {}
+}
+
+extension Int.NestedInMixedUses { // expected-error {{struct 'NestedInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
+  internal func internalMethod() {}
+}
+
+//--- imports.swift
+
+internal import InternalUsesOnly
+import InternalUsesOnlyDefaultedImport
+internal import PackageUsesOnly
+internal import PublicUsesOnly
+import PublicUsesOnlyDefaultedImport
+internal import MixedUses
+internal import ImportsOtherModules
+@_spiOnly public import InternalUsesOnlySPIOnly
+@_spiOnly import InternalUsesOnlyDefaultedImportSPIOnly
+@_spiOnly public import PublicUsesOnlySPIOnly
+
+//--- InternalUsesOnly.swift
+
+extension Int {
+  public typealias TypealiasInInternalUsesOnly = Self
+  public struct NestedInInternalUsesOnly {}
+  public var memberInInternalUsesOnly: Int { return self }
+}
+
+//--- InternalUsesOnlyDefaultedImport.swift
+
+extension Int {
+  public typealias TypealiasInInternalUsesOnlyDefaultedImport = Self
+  public struct NestedInInternalUsesOnlyDefaultedImport {}
+  public var memberInInternalUsesOnlyDefaultedImport: Int { return self }
+}
+
+//--- PackageUsesOnly.swift
+
+extension Int {
+  public typealias TypealiasInPackageUsesOnly = Self
+  public struct NestedInPackageUsesOnly {}
+  public var memberInPackageUsesOnly: Int { return self }
+}
+
+//--- PublicUsesOnly.swift
+
+extension Int {
+  public typealias TypealiasInPublicUsesOnly = Self
+  public struct NestedInPublicUsesOnly {}
+  public var memberInPublicUsesOnly: Int { return self }
+}
+
+//--- PublicUsesOnlyDefaultedImport.swift
+
+extension Int {
+  public typealias TypealiasInPublicUsesOnlyDefaultedImport = Self
+  public struct NestedInPublicUsesOnlyDefaultedImport {}
+  public var memberInPublicUsesOnlyDefaultedImport: Int { return self }
+}
+
+//--- MixedUses.swift
+
+extension Int {
+  public typealias TypealiasInMixedUses = Self
+  public struct NestedInMixedUses {}
+  public var memberInMixedUses: Int { return self }
+}
+
+//--- InternalUsesOnlyReexported.swift
+
+extension Int {
+  public typealias TypealiasInInternalUsesOnlyReexported = Self
+  public struct NestedInInternalUsesOnlyReexported {}
+  public var memberInInternalUsesOnlyReexported: Int { return self }
+}
+
+//--- InternalUsesOnlyTransitivelyImported.swift
+
+extension Int {
+  public typealias TypealiasInInternalUsesOnlyTransitivelyImported = Self
+  public struct NestedInInternalUsesOnlyTransitivelyImported {}
+  public var memberInInternalUsesOnlyTransitivelyImported: Int { return self }
+}
+
+//--- ImportsOtherModules.swift
+
+@_exported import InternalUsesOnlyReexported
+import InternalUsesOnlyTransitivelyImported
+
+//--- InternalUsesOnlySPIOnly.swift
+
+extension Int {
+  public var memberInInternalUsesOnlySPIOnly: Int { return self }
+}
+
+//--- InternalUsesOnlyDefaultedImportSPIOnly.swift
+
+extension Int {
+  public var memberInInternalUsesOnlyDefaultedImportSPIOnly: Int { return self }
+}
+
+//--- PublicUsesOnlySPIOnly.swift
+
+extension Int {
+  public var memberInPublicUsesOnlySPIOnly: Int { return self }
+}
diff --git a/test/NameLookup/member_import_visibility_objc.swift b/test/NameLookup/member_import_visibility_objc.swift
new file mode 100644
index 0000000000000..a12bb890a7c35
--- /dev/null
+++ b/test/NameLookup/member_import_visibility_objc.swift
@@ -0,0 +1,71 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/MemberImportVisibility -o %t %S/Inputs/MemberImportVisibility/Categories_A.swift
+// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/MemberImportVisibility -o %t %S/Inputs/MemberImportVisibility/Categories_B.swift
+// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/MemberImportVisibility -o %t %S/Inputs/MemberImportVisibility/Categories_C.swift
+// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/MemberImportVisibility -o %t %S/Inputs/MemberImportVisibility/Categories_E.swift
+// RUN: %target-swift-frontend -typecheck %s -I %t -I %S/Inputs/MemberImportVisibility -import-objc-header %S/Inputs/MemberImportVisibility/Bridging.h -verify -verify-ignore-unrelated -swift-version 5 -verify-additional-prefix no-member-visibility-
+// RUN: %target-swift-frontend -typecheck %s -I %t -I %S/Inputs/MemberImportVisibility -import-objc-header %S/Inputs/MemberImportVisibility/Bridging.h -verify -verify-ignore-unrelated -swift-version 6 -verify-additional-prefix no-member-visibility-
+// RUN: %target-swift-frontend -typecheck %s -I %t -I %S/Inputs/MemberImportVisibility -import-objc-header %S/Inputs/MemberImportVisibility/Bridging.h -verify -verify-ignore-unrelated -swift-version 5 -enable-upcoming-feature MemberImportVisibility -verify-additional-prefix member-visibility-
+
+// REQUIRES: objc_interop
+// REQUIRES: swift_feature_MemberImportVisibility
+
+import Categories_B
+import Categories_E
+
+// expected-member-visibility-note@-1 3 {{add import of module 'Categories_C'}}{{1-1=internal import Categories_C\n}}
+// expected-member-visibility-note@-2 {{add import of module 'Categories_D'}}{{1-1=internal import Categories_D\n}}
+func test(x: X) {
+  x.fromA()
+  x.fromOverlayForA()
+  x.overriddenInOverlayForA() // expected-warning {{'overriddenInOverlayForA()' is deprecated: Categories_A.swift}}
+  x.fromB()
+  x.fromOverlayForB()
+  x.overriddenInOverlayForB() // expected-warning {{'overriddenInOverlayForB()' is deprecated: Categories_B.swift}}
+  x.fromC() // expected-member-visibility-error {{instance method 'fromC()' is not available due to missing import of defining module 'Categories_C'}}
+  x.fromOverlayForC() // expected-member-visibility-error {{instance method 'fromOverlayForC()' is not available due to missing import of defining module 'Categories_C'}}
+  x.overriddenInOverlayForC()
+  // expected-no-member-visibility-warning@-1 {{'overriddenInOverlayForC()' is deprecated: Categories_C.swift}}
+  // expected-member-visibility-warning@-2 {{'overriddenInOverlayForC()' is deprecated: Categories_A.h}}
+  x.fromSubmoduleOfD() // expected-member-visibility-error {{instance method 'fromSubmoduleOfD()' is not available due to missing import of defining module 'Categories_D'}}
+  x.fromBridgingHeader()
+  x.overridesCategoryMethodOnNSObject()
+
+  let subclassFromC = makeSubclassFromC()
+  subclassFromC.overriddenInSubclassInOverlayForC()
+  // expected-warning@-1 {{'overriddenInSubclassInOverlayForC()' is deprecated: Categories_C.swift}}
+  // expected-member-visibility-error@-2 {{instance method 'overriddenInSubclassInOverlayForC()' is not available due to missing import of defining module 'Categories_C'}}
+}
+
+func testAnyObject(a: AnyObject) {
+  a.fromA()
+  a.fromOverlayForAObjC()
+  a.overriddenInOverlayForA() // expected-warning {{'overriddenInOverlayForA()' is deprecated: Categories_A.h}}
+  a.fromB()
+  a.fromOverlayForBObjC()
+  a.overriddenInOverlayForB() // expected-warning {{'overriddenInOverlayForB()' is deprecated: Categories_A.h}}
+  // FIXME: Better diagnostics?
+  // Name lookup for AnyObject already ignored transitive imports, so
+  // `MemberImportVisibility` has no effect on these diagnostics.
+  a.fromC() // expected-error {{value of type 'AnyObject' has no member 'fromC'}}
+  a.fromOverlayForCObjC() // expected-error {{value of type 'AnyObject' has no member 'fromOverlayForCObjC'}}
+  a.overriddenInOverlayForC() // expected-warning {{'overriddenInOverlayForC()' is deprecated: Categories_A.h}}
+  a.fromBridgingHeader()
+  a.overridesCategoryMethodOnNSObject()
+}
+
+extension StructInBridgingHeader {
+  init(_ x: Int32) {
+    self.init(member: x)
+  }
+
+  var wrappedMember: Int32 {
+    return member
+  }
+}
+
+extension ObjectInBridgingHeader {
+  func test() {
+    overridesCategoryMethodOnNSObject()
+  }
+}
diff --git a/test/NameLookup/member_import_visibility_objc_overrides.swift b/test/NameLookup/member_import_visibility_objc_overrides.swift
new file mode 100644
index 0000000000000..7324de9381056
--- /dev/null
+++ b/test/NameLookup/member_import_visibility_objc_overrides.swift
@@ -0,0 +1,318 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -typecheck \
+// RUN:   -primary-file %t/file1.swift \
+// RUN:   -primary-file %t/file2.swift \
+// RUN:   -primary-file %t/file3.swift \
+// RUN:   -primary-file %t/file4.swift \
+// RUN:   -primary-file %t/file5.swift \
+// RUN:   -I %S/Inputs/MemberImportVisibility/ObjCOverloads \
+// RUN:   -verify -verify-additional-prefix no-member-visibility-
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -typecheck \
+// RUN:   -primary-file %t/file1.swift \
+// RUN:   -primary-file %t/file2.swift \
+// RUN:   -primary-file %t/file3.swift \
+// RUN:   -primary-file %t/file4.swift \
+// RUN:   -primary-file %t/file5.swift \
+// RUN:   -I %S/Inputs/MemberImportVisibility/ObjCOverloads \
+// RUN:   -enable-upcoming-feature MemberImportVisibility \
+// RUN:   -verify -verify-additional-prefix member-visibility-
+
+// REQUIRES: objc_interop
+// REQUIRES: swift_feature_MemberImportVisibility
+
+//--- file1.swift
+
+import Root
+// expected-member-visibility-note 3 {{add import of module 'Branch'}}
+// expected-member-visibility-note@-1 2 {{add import of module 'Leaf'}}
+// expected-member-visibility-note@-2 2 {{add import of module 'Fruit'}}
+
+func testImportRoot_overridden1() {
+  makeRootObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Branch.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden1()' is not available due to missing import of defining module 'Branch'}}
+
+  makeLeafObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Leaf.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden1()' is not available due to missing import of defining module 'Leaf'}}
+
+  makeFruitObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Fruit.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden1()' is not available due to missing import of defining module 'Fruit'}}
+}
+
+func testImportRoot_overridden2() {
+  makeRootObject().overridden2()
+  // expected-warning@-1 {{'overridden2()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden2()
+  // expected-no-member-visibility-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden2()' is deprecated: Root.h}}
+
+  makeLeafObject().overridden2()
+  // expected-no-member-visibility-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden2()' is deprecated: Root.h}}
+
+  makeFruitObject().overridden2()
+  // expected-no-member-visibility-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden2()' is deprecated: Root.h}}
+}
+
+func testImportRoot_overridden3() {
+  makeRootObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Branch.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden3()' is not available due to missing import of defining module 'Branch'}}
+
+  makeLeafObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Leaf.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden3()' is not available due to missing import of defining module 'Leaf'}}
+
+  makeFruitObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Branch.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden3()' is not available due to missing import of defining module 'Branch'}}
+}
+
+func testImportRoot_overridden4() {
+  makeRootObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden4()
+  // expected-no-member-visibility-warning@-1 {{'overridden4()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden4()' is deprecated: Root.h}}
+
+  makeLeafObject().overridden4()
+  // expected-no-member-visibility-warning@-1 {{'overridden4()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden4()' is deprecated: Root.h}}
+
+  makeFruitObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Fruit.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden4()' is not available due to missing import of defining module 'Fruit'}}
+}
+
+
+//--- file2.swift
+
+import Branch
+// expected-member-visibility-note 2 {{add import of module 'Leaf'}}
+// expected-member-visibility-note@-1 2 {{add import of module 'Fruit'}}
+
+func testImportBranch_overridden1() {
+  makeRootObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Branch.h}}
+
+  makeLeafObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Leaf.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden1()' is not available due to missing import of defining module 'Leaf'}}
+
+  makeFruitObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Fruit.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden1()' is not available due to missing import of defining module 'Fruit'}}
+}
+
+func testImportBranch_overridden2() {
+  makeRootObject().overridden2()
+  // expected-warning@-1 {{'overridden2()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden2()
+  // expected-no-member-visibility-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden2()' is deprecated: Root.h}}
+
+  makeLeafObject().overridden2()
+  // expected-no-member-visibility-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden2()' is deprecated: Root.h}}
+
+  makeFruitObject().overridden2()
+  // expected-no-member-visibility-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden2()' is deprecated: Root.h}}
+}
+
+func testImportBranch_overridden3() {
+  makeRootObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Branch.h}}
+
+  makeLeafObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Leaf.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden3()' is not available due to missing import of defining module 'Leaf'}}
+
+  makeFruitObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Branch.h}}
+}
+
+func testImportBranch_overridden4() {
+  makeRootObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden4()
+  // expected-no-member-visibility-warning@-1 {{'overridden4()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden4()' is deprecated: Root.h}}
+
+  makeLeafObject().overridden4()
+  // expected-no-member-visibility-warning@-1 {{'overridden4()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden4()' is deprecated: Root.h}}
+
+  makeFruitObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Fruit.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden4()' is not available due to missing import of defining module 'Fruit'}}
+}
+
+
+//--- file3.swift
+
+import Leaf
+// expected-member-visibility-note 2 {{add import of module 'Fruit'}}
+
+func testImportLeaf_overridden1() {
+  makeRootObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Branch.h}}
+
+  makeLeafObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Leaf.h}}
+
+  makeFruitObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Fruit.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden1()' is not available due to missing import of defining module 'Fruit'}}
+}
+
+func testImportLeaf_overridden2() {
+  makeRootObject().overridden2()
+  // expected-warning@-1 {{'overridden2()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden2()
+  // expected-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+
+  makeLeafObject().overridden2()
+  // expected-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+
+  makeFruitObject().overridden2()
+  // expected-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+}
+
+func testImportLeaf_overridden3() {
+  makeRootObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Branch.h}}
+
+  makeLeafObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Leaf.h}}
+
+  makeFruitObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Branch.h}}
+}
+
+func testImportLeaf_overridden4() {
+  makeRootObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Leaf.h}}
+
+  makeLeafObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Leaf.h}}
+
+  makeFruitObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Fruit.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden4()' is not available due to missing import of defining module 'Fruit'}}
+}
+
+
+//--- file4.swift
+
+import Fruit
+// expected-member-visibility-note 2 {{add import of module 'Leaf'}}
+
+func testImportFruit_overridden1() {
+  makeRootObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Branch.h}}
+
+  makeLeafObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Leaf.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden1()' is not available due to missing import of defining module 'Leaf'}}
+
+  makeFruitObject().overridden1()
+  // expected-warning@-1 {{'overridden1()' is deprecated: Fruit.h}}
+}
+
+func testImportFruit_overridden2() {
+  makeRootObject().overridden2()
+  // expected-warning@-1 {{'overridden2()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden2()
+  // expected-no-member-visibility-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden2()' is deprecated: Root.h}}
+
+  makeLeafObject().overridden2()
+  // expected-no-member-visibility-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden2()' is deprecated: Root.h}}
+
+  makeFruitObject().overridden2()
+  // expected-no-member-visibility-warning@-1 {{'overridden2()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden2()' is deprecated: Root.h}}
+}
+
+func testImportFruit_overridden3() {
+  makeRootObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Branch.h}}
+
+  makeLeafObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Leaf.h}}
+  // expected-member-visibility-error@-2 {{instance method 'overridden3()' is not available due to missing import of defining module 'Leaf'}}
+
+  makeFruitObject().overridden3()
+  // expected-warning@-1 {{'overridden3()' is deprecated: Branch.h}}
+}
+
+func testImportFruit_overridden4() {
+  makeRootObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Root.h}}
+
+  makeBranchObject().overridden4()
+  // expected-no-member-visibility-warning@-1 {{'overridden4()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden4()' is deprecated: Root.h}}
+
+  makeLeafObject().overridden4()
+  // expected-no-member-visibility-warning@-1 {{'overridden4()' is deprecated: Leaf.h}}
+  // expected-member-visibility-warning@-2 {{'overridden4()' is deprecated: Root.h}}
+
+  makeFruitObject().overridden4()
+  // expected-warning@-1 {{'overridden4()' is deprecated: Fruit.h}}
+}
+
+
+//--- file5.swift
+
+import Root
+import Branch
+import Leaf
+import Fruit
+
+func makeRootObject() -> RootObject { RootObject() }
+func makeBranchObject() -> BranchObject { BranchObject() }
+func makeLeafObject() -> LeafObject { LeafObject() }
+func makeFruitObject() -> FruitObject { FruitObject() }
diff --git a/test/NameLookup/member_import_visibility_public_module_name.swift b/test/NameLookup/member_import_visibility_public_module_name.swift
new file mode 100644
index 0000000000000..9ab7f33e3ca43
--- /dev/null
+++ b/test/NameLookup/member_import_visibility_public_module_name.swift
@@ -0,0 +1,32 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -emit-module -o %t %t/LibCore.swift -public-module-name Lib
+// RUN: %target-swift-frontend -emit-module -I %t -o %t %t/Lib.swift
+// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %t/other.swift -I %t -verify -swift-version 5 -enable-upcoming-feature MemberImportVisibility
+
+// REQUIRES: swift_feature_MemberImportVisibility
+
+//--- main.swift
+
+import Swift
+// expected-note {{add import of module 'Lib'}}
+
+func foo(_ x: Int) -> Int {
+  x.bar // expected-error {{property 'bar' is not available due to missing import of defining module 'Lib'}}
+}
+
+//--- other.swift
+
+import Lib
+
+//--- Lib.swift
+
+@_exported import LibCore
+
+//--- LibCore.swift
+
+extension Int {
+  public var bar: Int {
+    return self < 0 ? -self : self
+  }
+}
diff --git a/test/NameLookup/members_transitive_underlying_clang.swift b/test/NameLookup/member_import_visibility_underlying_clang.swift
similarity index 100%
rename from test/NameLookup/members_transitive_underlying_clang.swift
rename to test/NameLookup/member_import_visibility_underlying_clang.swift
diff --git a/test/NameLookup/members_transitive.swift b/test/NameLookup/members_transitive.swift
deleted file mode 100644
index d6e94b5b4f055..0000000000000
--- a/test/NameLookup/members_transitive.swift
+++ /dev/null
@@ -1,103 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/MemberImportVisibility/members_A.swift
-// RUN: %target-swift-frontend -emit-module -I %t -o %t -package-name TestPackage %S/Inputs/MemberImportVisibility/members_B.swift
-// RUN: %target-swift-frontend -emit-module -I %t -o %t %S/Inputs/MemberImportVisibility/members_C.swift
-// RUN: %target-swift-frontend -typecheck %s -I %t -verify -swift-version 5 -package-name TestPackage -verify-additional-prefix ambiguity-
-// RUN: %target-swift-frontend -typecheck %s -I %t -verify -swift-version 6 -package-name TestPackage -verify-additional-prefix ambiguity-
-// RUN: %target-swift-frontend -typecheck %s -I %t -verify -swift-version 5 -package-name TestPackage -enable-upcoming-feature MemberImportVisibility -verify-additional-prefix member-visibility-
-
-// REQUIRES: swift_feature_MemberImportVisibility
-
-import members_C
-// expected-member-visibility-note 16{{add import of module 'members_B'}}{{1-1=internal import members_B\n}}
-
-
-func testExtensionMembers(x: X, y: Y<Z>) {
-  x.XinA()
-  y.YinA()
-
-  x.XinB() // expected-member-visibility-error{{instance method 'XinB()' is not available due to missing import of defining module 'members_B'}}
-  x.XinB_package() // expected-member-visibility-error{{instance method 'XinB_package()' is not available due to missing import of defining module 'members_B'}}
-  y.YinB() // expected-member-visibility-error{{instance method 'YinB()' is not available due to missing import of defining module 'members_B'}}
-
-  x.XinC()
-  y.YinC()
-
-  _ = X(true)
-  _ = X(1) // expected-member-visibility-error{{initializer 'init(_:)' is not available due to missing import of defining module 'members_B'}}
-
-  _ = x.ambiguous() // expected-ambiguity-error{{ambiguous use of 'ambiguous()'}}
-  let _: Bool = x.ambiguous()
-  let _: Int = x.ambiguous() // expected-member-visibility-error{{instance method 'ambiguous()' is not available due to missing import of defining module 'members_B'}}
-
-  // ambiguousDisfavored() has two overloads:
-  // - members_B: public func ambiguousDisfavored() -> Int
-  // - members_C: @_disfavoredOverload public func ambiguousDisfavored() -> Bool
-  // With MemberImportVisibility, the overload from members_C should be picked.
-  // Otherwise, the overload from members_B should be picked.
-  let disfavoredResult = x.ambiguousDisfavored()
-  let _: Bool = disfavoredResult // expected-ambiguity-error{{type 'Int' cannot be used as a boolean; test for '!= 0' instead}}
-  let _: Int = disfavoredResult // expected-member-visibility-error{{cannot convert value of type 'Bool' to specified type 'Int'}}
-  let _: Bool = x.ambiguousDisfavored()
-  let _: Int = x.ambiguousDisfavored() // expected-member-visibility-error{{instance method 'ambiguousDisfavored()' is not available due to missing import of defining module 'members_B'}}
-}
-
-func testOperatorMembers(x: X, y: Y<Z>) {
-  _ = x <<< x
-  _ = y <<< y
-
-  _ = x >>> x // expected-error{{cannot find operator '>>>' in scope}}
-  _ = y >>> y // expected-error{{cannot find operator '>>>' in scope}}
-
-  _ = x <> x
-  _ = y <> y
-}
-
-extension X {
-  var testProperties: (Bool, Bool, Bool, Bool) {
-    return (
-      propXinA,
-      propXinB, // expected-member-visibility-error{{property 'propXinB' is not available due to missing import of defining module 'members_B'}}
-      propXinB_package, // expected-member-visibility-error{{property 'propXinB_package' is not available due to missing import of defining module 'members_B}}
-      propXinC
-    )
-  }
-
-  func testNestedTypes() {
-    _ = NestedInA.self
-    _ = NestedInB.self // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
-    _ = NestedInB_package.self // expected-member-visibility-error{{struct 'NestedInB_package' is not available due to missing import of defining module 'members_B'}}
-    _ = NestedInC.self
-  }
-
-  var nestedInA: NestedInA { fatalError() }
-  var nestedInB: NestedInB { fatalError() } // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
-  var nestedInB_package: NestedInB_package { fatalError() } // expected-member-visibility-error{{struct 'NestedInB_package' is not available due to missing import of defining module 'members_B'}}
-  var nestedInC: NestedInC { fatalError() }
-}
-
-extension X.NestedInA {}
-extension X.NestedInB {} // expected-member-visibility-error{{struct 'NestedInB' is not available due to missing import of defining module 'members_B'}}
-extension X.NestedInB_package {} // expected-member-visibility-error{{struct 'NestedInB_package' is not available due to missing import of defining module 'members_B'}}
-extension X.NestedInC {}
-
-func testTopLevelTypes() {
-  _ = EnumInA.self
-  _ = EnumInB.self // expected-error{{cannot find 'EnumInB' in scope}}
-  _ = EnumInB_package.self // expected-error{{cannot find 'EnumInB_package' in scope}}
-  _ = EnumInC.self
-}
-
-class DerivedFromClassInC: DerivedClassInC {
-  override func methodInA() {}
-  override func methodInB() {} // expected-member-visibility-error{{instance method 'methodInB()' is not available due to missing import of defining module 'members_B'}}
-  override func methodInC() {}
-}
-
-struct ConformsToProtocolInA: ProtocolInA {} // expected-member-visibility-error{{type 'ConformsToProtocolInA' does not conform to protocol 'ProtocolInA'}} expected-member-visibility-note {{add stubs for conformance}}
-
-func testDerivedMethodAccess() {
-  DerivedClassInC().methodInC()
-  DerivedClassInC().methodInB() // expected-member-visibility-error{{instance method 'methodInB()' is not available due to missing import of defining module 'members_B'}}
-  DerivedFromClassInC().methodInB()
-}
diff --git a/test/NameLookup/members_transitive_multifile.swift b/test/NameLookup/members_transitive_multifile.swift
deleted file mode 100644
index 4a37c69759ecf..0000000000000
--- a/test/NameLookup/members_transitive_multifile.swift
+++ /dev/null
@@ -1,44 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/MemberImportVisibility/members_A.swift
-// RUN: %target-swift-frontend -emit-module -I %t -o %t -package-name TestPackage %S/Inputs/MemberImportVisibility/members_B.swift
-// RUN: %target-swift-frontend -emit-module -I %t -o %t %S/Inputs/MemberImportVisibility/members_C.swift
-// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %t/A.swift %t/B.swift %t/C.swift -I %t -verify -swift-version 5
-// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %t/A.swift %t/B.swift %t/C.swift -I %t -verify -swift-version 6
-// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %t/A.swift %t/B.swift %t/C.swift -I %t -verify -swift-version 5 -enable-upcoming-feature MemberImportVisibility -verify-additional-prefix member-visibility-
-
-// REQUIRES: swift_feature_MemberImportVisibility
-
-//--- main.swift
-
-// expected-member-visibility-note@+2 {{add import of module 'members_A'}}{{1-1=@_implementationOnly import members_A\n}}
-// expected-member-visibility-note@+1 {{add import of module 'members_C'}}{{1-1=@_weakLinked @_spiOnly import members_C\n}}
-func testMembersWithInferredContextualBase() {
-  takesEnumInA(.caseInA) // expected-member-visibility-error{{enum case 'caseInA' is not available due to missing import of defining module 'members_A'}}
-  takesEnumInB(.caseInB)
-  takesEnumInC(.caseInC) // expected-member-visibility-error{{enum case 'caseInC' is not available due to missing import of defining module 'members_C'}}
-}
-
-func testQualifiedMembers() {
-  takesEnumInA(EnumInA.caseInA) // expected-error{{cannot find 'EnumInA' in scope; did you mean 'EnumInB'?}}
-  takesEnumInB(EnumInB.caseInB)
-  takesEnumInC(EnumInC.caseInC) // expected-error{{cannot find 'EnumInC' in scope; did you mean 'EnumInB'?}}
-}
-
-//--- A.swift
-
-@_implementationOnly import members_A
-
-func takesEnumInA(_ e: EnumInA) {}
-
-//--- B.swift
-
-@_exported import members_B
-
-func takesEnumInB(_ e: EnumInB) {}
-
-//--- C.swift
-
-@_spiOnly @_weakLinked import members_C
-
-func takesEnumInC(_ e: EnumInC) {}
diff --git a/test/NameLookup/members_transitive_multifile_access_level.swift b/test/NameLookup/members_transitive_multifile_access_level.swift
deleted file mode 100644
index 4e72f97d2358d..0000000000000
--- a/test/NameLookup/members_transitive_multifile_access_level.swift
+++ /dev/null
@@ -1,230 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnly.swift
-// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyDefaultedImport.swift
-// RUN: %target-swift-frontend -emit-module -o %t %t/PackageUsesOnly.swift
-// RUN: %target-swift-frontend -emit-module -o %t %t/PublicUsesOnly.swift
-// RUN: %target-swift-frontend -emit-module -o %t %t/PublicUsesOnlyDefaultedImport.swift
-// RUN: %target-swift-frontend -emit-module -o %t %t/MixedUses.swift
-// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyTransitivelyImported.swift
-// RUN: %target-swift-frontend -emit-module -o %t %t/Exports.swift -I %t
-// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlySPIOnly.swift -I %t
-// RUN: %target-swift-frontend -emit-module -o %t %t/InternalUsesOnlyDefaultedImportSPIOnly.swift -I %t
-// RUN: %target-swift-frontend -emit-module -o %t %t/PublicUsesOnlySPIOnly.swift -I %t
-
-// RUN: %target-swift-frontend -typecheck -verify -swift-version 5 \
-// RUN:   -primary-file %t/function_bodies.swift \
-// RUN:   -primary-file %t/function_signatures_unqualified.swift \
-// RUN:   -primary-file %t/function_signatures_qualified.swift \
-// RUN:   -primary-file %t/extensions.swift \
-// RUN:   %t/imports.swift \
-// RUN:   -I %t -package-name Package \
-// RUN:   -enable-upcoming-feature MemberImportVisibility \
-// RUN:   -verify-additional-prefix public-by-default-
-
-// RUN: %target-swift-frontend -typecheck -verify -swift-version 5 \
-// RUN:   -primary-file %t/function_bodies.swift \
-// RUN:   -primary-file %t/function_signatures_unqualified.swift \
-// RUN:   -primary-file %t/function_signatures_qualified.swift \
-// RUN:   -primary-file %t/extensions.swift \
-// RUN:   %t/imports.swift \
-// RUN:   -I %t -package-name Package \
-// RUN:   -enable-upcoming-feature MemberImportVisibility \
-// RUN:   -enable-upcoming-feature InternalImportsByDefault \
-// RUN:   -verify-additional-prefix internal-by-default-
-
-// REQUIRES: swift_feature_InternalImportsByDefault
-// REQUIRES: swift_feature_MemberImportVisibility
-
-//--- function_bodies.swift
-
-// FIXME: The access level on the fix-it for PackageUsesOnly is wrong.
-import Swift // Just here to anchor the fix-its
-// expected-note      {{add import of module 'InternalUsesOnly'}}{{1-1=internal import InternalUsesOnly\n}}
-// expected-note@-1   {{add import of module 'InternalUsesOnlyDefaultedImport'}}{{1-1=import InternalUsesOnlyDefaultedImport\n}}
-// expected-note@-2   {{add import of module 'PackageUsesOnly'}}{{1-1=public import PackageUsesOnly\n}}
-// expected-note@-3   {{add import of module 'PublicUsesOnly'}}{{1-1=public import PublicUsesOnly\n}}
-// expected-note@-4   {{add import of module 'PublicUsesOnlyDefaultedImport'}}{{1-1=import PublicUsesOnlyDefaultedImport\n}}
-// expected-note@-5 3 {{add import of module 'MixedUses'}}{{1-1=public import MixedUses\n}}
-// expected-note@-6   {{add import of module 'InternalUsesOnlyTransitivelyImported'}}{{1-1=internal import InternalUsesOnlyTransitivelyImported\n}}
-// expected-note@-7   {{add import of module 'InternalUsesOnlySPIOnly'}}{{1-1=internal import InternalUsesOnlySPIOnly\n}}
-// expected-public-by-default-note@-8     {{add import of module 'InternalUsesOnlyDefaultedImportSPIOnly'}}{{1-1=@_spiOnly import InternalUsesOnlyDefaultedImportSPIOnly\n}}
-// expected-internal-by-default-note@-9   {{add import of module 'InternalUsesOnlyDefaultedImportSPIOnly'}}{{1-1=import InternalUsesOnlyDefaultedImportSPIOnly\n}}
-// expected-note@-10  {{add import of module 'PublicUsesOnlySPIOnly'}}{{1-1=@_spiOnly public import PublicUsesOnlySPIOnly\n}}
-
-
-func internalFunc(_ x: Int) {
-  _ = x.memberInInternalUsesOnly // expected-error {{property 'memberInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
-  _ = x.memberInInternalUsesOnlyDefaultedImport // expected-error {{property 'memberInInternalUsesOnlyDefaultedImport' is not available due to missing import of defining module 'InternalUsesOnlyDefaultedImport'}}
-  _ = x.memberInMixedUses // expected-error {{property 'memberInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
-  _ = x.memberInInternalUsesOnlyTransitivelyImported // expected-error {{property 'memberInInternalUsesOnlyTransitivelyImported' is not available due to missing import of defining module 'InternalUsesOnlyTransitivelyImported'}}
-  _ = x.memberInInternalUsesOnlySPIOnly // expected-error {{property 'memberInInternalUsesOnlySPIOnly' is not available due to missing import of defining module 'InternalUsesOnlySPIOnly'}}
-  _ = x.memberInInternalUsesOnlyDefaultedImportSPIOnly // expected-error {{property 'memberInInternalUsesOnlyDefaultedImportSPIOnly' is not available due to missing import of defining module 'InternalUsesOnlyDefaultedImportSPIOnly'}}
-}
-
-@inlinable package func packageInlinableFunc(_ x: Int) {
-  _ = x.memberInPackageUsesOnly // expected-error {{property 'memberInPackageUsesOnly' is not available due to missing import of defining module 'PackageUsesOnly'}}
-  _ = x.memberInMixedUses // expected-error {{property 'memberInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
-}
-
-@inlinable public func inlinableFunc(_ x: Int) {
-  _ = x.memberInPublicUsesOnly // expected-error {{property 'memberInPublicUsesOnly' is not available due to missing import of defining module 'PublicUsesOnly'}}
-  _ = x.memberInPublicUsesOnlyDefaultedImport // expected-error {{property 'memberInPublicUsesOnlyDefaultedImport' is not available due to missing import of defining module 'PublicUsesOnlyDefaultedImport'}}
-  _ = x.memberInMixedUses // expected-error {{property 'memberInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
-  _ = x.memberInPublicUsesOnlySPIOnly // expected-error {{property 'memberInPublicUsesOnlySPIOnly' is not available due to missing import of defining module 'PublicUsesOnlySPIOnly'}}
-}
-
-//--- function_signatures_unqualified.swift
-
-import Swift // Just here to anchor the fix-its
-// expected-note    2 {{add import of module 'InternalUsesOnly'}}{{1-1=internal import InternalUsesOnly\n}}
-// expected-note@-1   {{add import of module 'PackageUsesOnly'}}{{1-1=package import PackageUsesOnly\n}}
-// expected-note@-2   {{add import of module 'PublicUsesOnly'}}{{1-1=public import PublicUsesOnly\n}}
-// expected-note@-3 2 {{add import of module 'MixedUses'}}{{1-1=public import MixedUses\n}}
-
-extension Int {
-  private func usesTypealiasInInternalUsesOnly_Private(x: TypealiasInInternalUsesOnly) {} // expected-error {{type alias 'TypealiasInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
-  internal func usesTypealiasInInternalUsesOnly(x: TypealiasInInternalUsesOnly) {} // expected-error {{type alias 'TypealiasInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
-  package func usesTypealiasInPackageUsesOnly(x: TypealiasInPackageUsesOnly) {} // expected-error {{type alias 'TypealiasInPackageUsesOnly' is not available due to missing import of defining module 'PackageUsesOnly'}}
-  public func usesTypealiasInPublicUsesOnly(x: TypealiasInPublicUsesOnly) {} // expected-error {{type alias 'TypealiasInPublicUsesOnly' is not available due to missing import of defining module 'PublicUsesOnly'}}
-  public func usesTypealiasInMixedUses(x: TypealiasInMixedUses) {} // expected-error {{type alias 'TypealiasInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
-  internal func usesTypealiasInMixedUses_Internal(x: TypealiasInMixedUses) {} // expected-error {{type alias 'TypealiasInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
-}
-
-//--- function_signatures_qualified.swift
-
-import Swift // Just here to anchor the fix-its
-// expected-note    2 {{add import of module 'InternalUsesOnly'}}{{1-1=internal import InternalUsesOnly\n}}
-// expected-note@-1   {{add import of module 'PackageUsesOnly'}}{{1-1=package import PackageUsesOnly\n}}
-// expected-note@-2   {{add import of module 'PublicUsesOnly'}}{{1-1=public import PublicUsesOnly\n}}
-// expected-note@-3 2 {{add import of module 'MixedUses'}}{{1-1=public import MixedUses\n}}
-
-private func usesTypealiasInInternalUsesOnly_Private(x: Int.TypealiasInInternalUsesOnly) {} // expected-error {{type alias 'TypealiasInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
-internal func usesTypealiasInInternalUsesOnly(x: Int.TypealiasInInternalUsesOnly) {} // expected-error {{type alias 'TypealiasInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
-package func usesTypealiasInPackageUsesOnly(x: Int.TypealiasInPackageUsesOnly) {} // expected-error {{type alias 'TypealiasInPackageUsesOnly' is not available due to missing import of defining module 'PackageUsesOnly'}}
-public func usesTypealiasInPublicUsesOnly(x: Int.TypealiasInPublicUsesOnly) {} // expected-error {{type alias 'TypealiasInPublicUsesOnly' is not available due to missing import of defining module 'PublicUsesOnly'}}
-public func usesTypealiasInMixedUses(x: Int.TypealiasInMixedUses) {} // expected-error {{type alias 'TypealiasInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
-internal func usesTypealiasInMixedUses_Internal(x: Int.TypealiasInMixedUses) {} // expected-error {{type alias 'TypealiasInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
-
-//--- extensions.swift
-
-import Swift // Just here to anchor the fix-its
-// expected-note    2 {{add import of module 'InternalUsesOnly'}}{{1-1=internal import InternalUsesOnly\n}}
-// expected-note@-1   {{add import of module 'PackageUsesOnly'}}{{1-1=package import PackageUsesOnly\n}}
-// expected-note@-2   {{add import of module 'PublicUsesOnly'}}{{1-1=public import PublicUsesOnly\n}}
-// expected-note@-3 2 {{add import of module 'MixedUses'}}{{1-1=public import MixedUses\n}}
-
-extension Int.NestedInInternalUsesOnly { // expected-error {{struct 'NestedInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
-  private func privateMethod() {}
-}
-
-extension Int.NestedInInternalUsesOnly { // expected-error {{struct 'NestedInInternalUsesOnly' is not available due to missing import of defining module 'InternalUsesOnly'}}
-  internal func internalMethod() {}
-}
-
-extension Int.NestedInPackageUsesOnly { // expected-error {{struct 'NestedInPackageUsesOnly' is not available due to missing import of defining module 'PackageUsesOnly'}}
-  package func packageMethod() {}
-}
-
-extension Int.NestedInPublicUsesOnly { // expected-error {{struct 'NestedInPublicUsesOnly' is not available due to missing import of defining module 'PublicUsesOnly'}}
-  public func publicMethod() {}
-}
-
-extension Int.NestedInMixedUses { // expected-error {{struct 'NestedInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
-  public func publicMethod() {}
-}
-
-extension Int.NestedInMixedUses { // expected-error {{struct 'NestedInMixedUses' is not available due to missing import of defining module 'MixedUses'}}
-  internal func internalMethod() {}
-}
-
-//--- imports.swift
-
-internal import InternalUsesOnly
-import InternalUsesOnlyDefaultedImport
-internal import PackageUsesOnly
-internal import PublicUsesOnly
-import PublicUsesOnlyDefaultedImport
-internal import MixedUses
-internal import Exports
-@_spiOnly public import InternalUsesOnlySPIOnly
-@_spiOnly import InternalUsesOnlyDefaultedImportSPIOnly
-@_spiOnly public import PublicUsesOnlySPIOnly
-
-//--- InternalUsesOnly.swift
-
-extension Int {
-  public typealias TypealiasInInternalUsesOnly = Self
-  public struct NestedInInternalUsesOnly {}
-  public var memberInInternalUsesOnly: Int { return self }
-}
-
-//--- InternalUsesOnlyDefaultedImport.swift
-
-extension Int {
-  public typealias TypealiasInInternalUsesOnlyDefaultedImport = Self
-  public struct NestedInInternalUsesOnlyDefaultedImport {}
-  public var memberInInternalUsesOnlyDefaultedImport: Int { return self }
-}
-
-//--- PackageUsesOnly.swift
-
-extension Int {
-  public typealias TypealiasInPackageUsesOnly = Self
-  public struct NestedInPackageUsesOnly {}
-  public var memberInPackageUsesOnly: Int { return self }
-}
-
-//--- PublicUsesOnly.swift
-
-extension Int {
-  public typealias TypealiasInPublicUsesOnly = Self
-  public struct NestedInPublicUsesOnly {}
-  public var memberInPublicUsesOnly: Int { return self }
-}
-
-//--- PublicUsesOnlyDefaultedImport.swift
-
-extension Int {
-  public typealias TypealiasInPublicUsesOnlyDefaultedImport = Self
-  public struct NestedInPublicUsesOnlyDefaultedImport {}
-  public var memberInPublicUsesOnlyDefaultedImport: Int { return self }
-}
-
-//--- MixedUses.swift
-
-extension Int {
-  public typealias TypealiasInMixedUses = Self
-  public struct NestedInMixedUses {}
-  public var memberInMixedUses: Int { return self }
-}
-
-//--- InternalUsesOnlyTransitivelyImported.swift
-
-extension Int {
-  public typealias TypealiasInInternalUsesOnlyTransitivelyImported = Self
-  public struct NestedInInternalUsesOnlyTransitivelyImported {}
-  public var memberInInternalUsesOnlyTransitivelyImported: Int { return self }
-}
-
-//--- Exports.swift
-
-@_exported import InternalUsesOnlyTransitivelyImported
-
-//--- InternalUsesOnlySPIOnly.swift
-
-extension Int {
-  public var memberInInternalUsesOnlySPIOnly: Int { return self }
-}
-
-//--- InternalUsesOnlyDefaultedImportSPIOnly.swift
-
-extension Int {
-  public var memberInInternalUsesOnlyDefaultedImportSPIOnly: Int { return self }
-}
-
-//--- PublicUsesOnlySPIOnly.swift
-
-extension Int {
-  public var memberInPublicUsesOnlySPIOnly: Int { return self }
-}
diff --git a/test/NameLookup/members_transitive_objc.swift b/test/NameLookup/members_transitive_objc.swift
deleted file mode 100644
index 0ea3b994fe864..0000000000000
--- a/test/NameLookup/members_transitive_objc.swift
+++ /dev/null
@@ -1,58 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/MemberImportVisibility -o %t %S/Inputs/MemberImportVisibility/Categories_A.swift
-// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/MemberImportVisibility -o %t %S/Inputs/MemberImportVisibility/Categories_B.swift
-// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/MemberImportVisibility -o %t %S/Inputs/MemberImportVisibility/Categories_C.swift
-// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/MemberImportVisibility -o %t %S/Inputs/MemberImportVisibility/Categories_E.swift
-// RUN: %target-swift-frontend -typecheck %s -I %t -I %S/Inputs/MemberImportVisibility -import-objc-header %S/Inputs/MemberImportVisibility/Bridging.h -verify -swift-version 5
-// RUN: %target-swift-frontend -typecheck %s -I %t -I %S/Inputs/MemberImportVisibility -import-objc-header %S/Inputs/MemberImportVisibility/Bridging.h -verify -swift-version 6
-// RUN: %target-swift-frontend -typecheck %s -I %t -I %S/Inputs/MemberImportVisibility -import-objc-header %S/Inputs/MemberImportVisibility/Bridging.h -verify -swift-version 5 -enable-upcoming-feature MemberImportVisibility -verify-additional-prefix member-visibility-
-
-// REQUIRES: objc_interop
-// REQUIRES: swift_feature_MemberImportVisibility
-
-import Categories_B
-import Categories_E
-
-// expected-member-visibility-note@-1 2 {{add import of module 'Categories_C'}}{{1-1=internal import Categories_C\n}}
-// expected-member-visibility-note@-2 {{add import of module 'Categories_D'}}{{1-1=internal import Categories_D\n}}
-func test(x: X) {
-  x.fromA()
-  x.fromOverlayForA()
-  x.fromB()
-  x.fromOverlayForB()
-  x.fromC() // expected-member-visibility-error {{instance method 'fromC()' is not available due to missing import of defining module 'Categories_C'}}
-  x.fromOverlayForC() // expected-member-visibility-error {{instance method 'fromOverlayForC()' is not available due to missing import of defining module 'Categories_C'}}
-  x.fromSubmoduleOfD() // expected-member-visibility-error {{instance method 'fromSubmoduleOfD()' is not available due to missing import of defining module 'Categories_D'}}
-  x.fromBridgingHeader()
-  x.overridesCategoryMethodOnNSObject()
-}
-
-func testAnyObject(a: AnyObject) {
-  a.fromA()
-  a.fromOverlayForAObjC()
-  a.fromB()
-  a.fromOverlayForBObjC()
-  // FIXME: Better diagnostics?
-  // Name lookup for AnyObject already ignored transitive imports, so
-  // `MemberImportVisibility` has no effect on these diagnostics.
-  a.fromC() // expected-error {{value of type 'AnyObject' has no member 'fromC'}}
-  a.fromOverlayForCObjC() // expected-error {{value of type 'AnyObject' has no member 'fromOverlayForCObjC'}}
-  a.fromBridgingHeader()
-  a.overridesCategoryMethodOnNSObject()
-}
-
-extension StructInBridgingHeader {
-  init(_ x: Int32) {
-    self.init(member: x)
-  }
-
-  var wrappedMember: Int32 {
-    return member
-  }
-}
-
-extension ObjectInBridgingHeader {
-  func test() {
-    overridesCategoryMethodOnNSObject()
-  }
-}
diff --git a/test/NameLookup/module_selector.swift b/test/NameLookup/module_selector.swift
new file mode 100644
index 0000000000000..0efc97316ec2c
--- /dev/null
+++ b/test/NameLookup/module_selector.swift
@@ -0,0 +1,3 @@
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature ModuleSelector
+
+// REQUIRES: swift_feature_ModuleSelector
diff --git a/test/NameLookup/name_lookup.swift b/test/NameLookup/name_lookup.swift
index 4757f8ec34217..0b969aab367a0 100644
--- a/test/NameLookup/name_lookup.swift
+++ b/test/NameLookup/name_lookup.swift
@@ -637,17 +637,14 @@ struct PatternBindingWithTwoVars2 { var x = y, y = 3 }
 // expected-error@-1 {{cannot use instance member 'y' within property initializer; property initializers run before 'self' is available}}
 
 struct PatternBindingWithTwoVars3 { var x = y, y = x }
-// expected-error@-1 {{circular reference}}
-// expected-note@-2 {{through reference here}}
-// expected-note@-3 {{through reference here}}
-// expected-note@-4 {{through reference here}}
-// expected-note@-5 {{through reference here}}
-// expected-note@-6 {{through reference here}}
+// expected-error@-1:41 {{circular reference}}
+// expected-note@-2:37 {{through reference here}}
+// expected-note@-3:48 {{through reference here}}
 
 // https://github.com/apple/swift/issues/51518
 do {
-  let closure1 = { closure2() } // expected-error {{circular reference}} expected-note {{through reference here}} expected-note {{through reference here}}
-  let closure2 = { closure1() } // expected-note {{through reference here}} expected-note {{through reference here}} expected-note {{through reference here}}
+  let closure1 = { closure2() } // expected-error {{circular reference}} expected-note {{through reference here}}
+  let closure2 = { closure1() } // expected-note {{through reference here}} expected-note {{through reference here}}
 }
 
 func color(with value: Int) -> Int {
diff --git a/test/NameLookup/name_lookup2.swift b/test/NameLookup/name_lookup2.swift
index b188d6097ec26..a7f4177d1ada9 100644
--- a/test/NameLookup/name_lookup2.swift
+++ b/test/NameLookup/name_lookup2.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck %s -module-name themodule -enable-source-import -I %S/../decl/enum -sdk "" -verify -show-diagnostics-after-fatal -verify-ignore-unknown
+// RUN: %target-swift-frontend -typecheck %s -module-name themodule -enable-source-import -I %S/../decl/enum -sdk "" -verify -verify-ignore-unrelated -show-diagnostics-after-fatal -verify-ignore-unknown
 
 // -verify-ignore-unknown is for
 // <unknown>:0: error: unexpected note produced: did you forget to set an SDK using -sdk or SDKROOT?
diff --git a/test/NameLookup/name_lookup_min_max_conditional_conformance.swift b/test/NameLookup/name_lookup_min_max_conditional_conformance.swift
index e79212e6aa318..4bc0c144bd6e5 100644
--- a/test/NameLookup/name_lookup_min_max_conditional_conformance.swift
+++ b/test/NameLookup/name_lookup_min_max_conditional_conformance.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 extension Range {
     func f(_ value: Bound) -> Bound {
diff --git a/test/NameLookup/private_import.swift b/test/NameLookup/private_import.swift
index e9f2a881e9910..d0ce3c246f91d 100644
--- a/test/NameLookup/private_import.swift
+++ b/test/NameLookup/private_import.swift
@@ -30,7 +30,7 @@
 // RUN: %target-swift-frontend -emit-module -module-name Host -I %t -emit-module-path %t/Host.swiftmodule -enable-private-imports %s %S/Inputs/private_import/Host.swift
 
 // Build a thunk for the host module.
-// RUN: %target-typecheck-verify-swift -parse-as-library -I %t -DCOMPILING_THUNK
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -parse-as-library -I %t -DCOMPILING_THUNK
 
 #if COMPILING_THUNK
 @_private(sourceFile: "private_import.swift") import Host
diff --git a/test/Parse/ConditionalCompilation/can_import_in_inactive.swift b/test/Parse/ConditionalCompilation/can_import_in_inactive.swift
index 218a5e7912b72..4edc561fce25e 100644
--- a/test/Parse/ConditionalCompilation/can_import_in_inactive.swift
+++ b/test/Parse/ConditionalCompilation/can_import_in_inactive.swift
@@ -21,7 +21,7 @@
 #endif
 
 #if canImport(SomeModule)
-// CHECK: :[[@LINE-1]]:{{.*}}: error: could not find module 'SomeModule' for target '{{.*}}'; found: i386
+// CHECK: :[[@LINE-1]]:{{.*}}: warning: could not find module 'SomeModule' for target '{{.*}}'; found: i386
 #endif
 
 import SomeModule
diff --git a/test/Parse/attribute_spacing.swift b/test/Parse/attribute_spacing.swift
index e759f4132cad2..337b698c2be81 100644
--- a/test/Parse/attribute_spacing.swift
+++ b/test/Parse/attribute_spacing.swift
@@ -18,6 +18,10 @@ struct MyPropertyWrapper {
 struct PropertyWrapperTest {
   @MyPropertyWrapper (param: 2)  // expected-warning {{extraneous whitespace between attribute name and '('; this is an error in the Swift 6 language mode}}
   var x: Int
+
+  @MyPropertyWrapper
+  (param: 2) // expected-error {{expected 'var' keyword in property declaration}} expected-error {{property declaration does not bind any variables}} expected-error {{expected pattern}}
+  var y: Int
 }
 
 let closure1 = { @MainActor (a, b) in // expected-warning {{extraneous whitespace between attribute name and '('; this is an error in the Swift 6 language mode}}
@@ -31,3 +35,10 @@ let closure2 = { @MainActor
 @ 
 MainActor
 func mainActorFunc() {}
+
+
+@inline // expected-error {{expected '(' in 'inline' attribute}}
+(never) func neverInline() {} // expected-error {{expected declaration}}
+
+@objc
+(whatever) func whateverObjC() {} // expected-error {{expected declaration}}
diff --git a/test/Parse/attribute_spacing_swift6.swift b/test/Parse/attribute_spacing_swift6.swift
new file mode 100644
index 0000000000000..b791feb475c0c
--- /dev/null
+++ b/test/Parse/attribute_spacing_swift6.swift
@@ -0,0 +1,47 @@
+// RUN: %target-typecheck-verify-swift -swift-version 6
+
+@ MainActor  // expected-error {{extraneous whitespace between '@' and attribute name}}
+class Foo {
+  func funcWithEscapingClosure(_ x: @ escaping () -> Int) {} // expected-error {{extraneous whitespace between '@' and attribute name}}
+}
+
+@available (*, deprecated) // expected-error {{extraneous whitespace between attribute name and '('}}
+func deprecated() {}
+
+@propertyWrapper
+struct MyPropertyWrapper {
+  var wrappedValue: Int = 1
+
+  init(param: Int) {}
+}
+
+struct PropertyWrapperTest {
+  @MyPropertyWrapper (param: 2)  // expected-error {{extraneous whitespace between attribute name and '('}}
+  var x: Int
+
+  @MyPropertyWrapper
+  (param: 2) // expected-error {{expected 'var' keyword in property declaration}} expected-error {{property declaration does not bind any variables}} expected-error {{expected pattern}}
+  var y: Int
+}
+
+let closure1 = { @MainActor (a, b) in 
+// expected-error@-1 {{cannot infer type of closure parameter 'a' without a type annotation}}
+// expected-error@-2 {{cannot infer type of closure parameter 'b' without a type annotation}}
+}
+
+let closure2 = { @MainActor
+  (a: Int, b: Int) in
+  let _: Int = a
+}
+
+// expected-error@+1 {{extraneous whitespace between '@' and attribute name}}
+@ 
+MainActor
+func mainActorFunc() {}
+
+
+@inline // expected-error {{expected '(' in 'inline' attribute}}
+(never) func neverInline() {} // expected-error {{expected declaration}}
+
+@objc
+(whatever) func whateverObjC() {} // expected-error {{expected declaration}}
diff --git a/test/Parse/availability_query.swift b/test/Parse/availability_query.swift
index ae2a58e7662f8..5c59e30246031 100644
--- a/test/Parse/availability_query.swift
+++ b/test/Parse/availability_query.swift
@@ -45,6 +45,9 @@ if #available(OSX 0.0) { // expected-warning {{expected version number; this is
 if #available(OSX 51 { // expected-error {{expected ')'}} expected-note {{to match this opening '('}}
 }
 
+if #available(iDishwasherOS 0) { // expected-warning {{expected version number; this is an error in the Swift 6 language mode}}
+}
+
 if #available(iDishwasherOS 51) { // expected-warning {{unrecognized platform name 'iDishwasherOS'}}
 // expected-error@-1 {{condition required for target platform}}
 }
diff --git a/test/Parse/availability_query_custom_domains.swift b/test/Parse/availability_query_custom_domains.swift
index 1b176b437bc42..e556a17151bc9 100644
--- a/test/Parse/availability_query_custom_domains.swift
+++ b/test/Parse/availability_query_custom_domains.swift
@@ -9,13 +9,13 @@
 if #available(EnabledDomain) { }
 if #available(DisabledDomain) { }
 if #available(DynamicDomain) { }
-if #available(UnknownDomain) { } // expected-warning {{unrecognized platform name 'UnknownDomain'}}
+if #available(UnknownDomain) { } // expected-error {{unrecognized platform name 'UnknownDomain'}}
 // expected-error@-1 {{condition required for target platform}}
 
 if #unavailable(EnabledDomain) { }
 if #unavailable(DisabledDomain) { }
 if #unavailable(DynamicDomain) { }
-if #unavailable(UnknownDomain) { } // expected-warning {{unrecognized platform name 'UnknownDomain'}}
+if #unavailable(UnknownDomain) { } // expected-error {{unrecognized platform name 'UnknownDomain'}}
 
 if #available(EnabledDomain 1.0) { } // expected-error {{unexpected version number for EnabledDomain}}
 if #available(EnabledDomain, DisabledDomain) { } // expected-error {{EnabledDomain availability must be specified alone}}
diff --git a/test/Parse/borrow_and_mutate_accessors.swift b/test/Parse/borrow_and_mutate_accessors.swift
new file mode 100644
index 0000000000000..f45e71fadd6d8
--- /dev/null
+++ b/test/Parse/borrow_and_mutate_accessors.swift
@@ -0,0 +1,124 @@
+// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature BorrowAndMutateAccessors -enable-experimental-feature CoroutineAccessors
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+// REQUIRES: swift_feature_CoroutineAccessors
+
+class Klass {}
+
+struct Wrapper {
+  let _k: Klass
+  var _otherK: Klass
+
+  var k1: Klass {
+    borrow {
+      return _k 
+    }
+  }
+  var k2: Klass {
+    borrow { // expected-error{{variable cannot provide both  a 'borrow' accessor and a getter}}
+      return _k
+    }
+    get { // expected-note{{getter defined here}}
+      return _k
+    }
+  }
+  var k3: Klass {
+    borrow { // expected-error{{variable cannot provide both  a 'borrow' accessor and a '_read' accessor}}
+      return _k
+    }
+    _read { // expected-note{{'_read' accessor defined here}}
+      yield _k
+    }
+  }
+  var k4: Klass {
+    borrow { // expected-error{{variable cannot provide both  a 'borrow' accessor and a 'read' accessor}}
+      return _k
+    }
+    read { // expected-note{{'read' accessor defined here}}
+      yield _k
+    }
+  }
+  var k5: Klass {
+    mutate { // expected-error{{variable with a 'mutate' accessor must also have a 'borrow' accessor, getter, addressor or 'read' accessor}}
+      return &_otherK
+    }
+  }
+  var k6: Klass {
+    borrow {
+      return _otherK
+    }
+    mutate { // expected-error{{variable cannot provide both a 'mutate' accessor and a setter}}
+      return &_otherK
+    }
+    _modify {
+      yield &_otherK
+    }
+    set { // expected-note{{setter defined here}}
+      _otherK = newValue
+    }
+  }
+  var k7: Klass {
+    borrow {
+      return _otherK
+    }
+    mutate { // expected-note{{mutate accessor defined here}}
+      return &_otherK
+    }
+    unsafeMutableAddress { // expected-error{{variable cannot provide both a mutable addressor and a 'mutate' accessor}}
+    }
+  }
+  var k8: Klass {
+    borrow async throws { // expected-error{{'borrow' accessor cannot have specifier 'async'}} expected-error{{'borrow' accessor cannot have specifier 'throws'}}
+      return _otherK
+    }
+    mutate async throws { // expected-error{{'mutate' accessor cannot have specifier 'async'}} expected-error{{'mutate' accessor cannot have specifier 'throws'}}
+      return &_otherK
+    }
+  }
+}
+
+var i: Int
+
+var i_accessor: Int {
+  borrow { // expected-error{{a 'borrow' accessor is supported only on a struct or enum}}
+    fatalError()
+  }
+  mutate { // expected-error{{a 'mutate' accessor is supported only on a struct or enum}}
+    return &i // expected-error{{'&' may only be used to pass an argument to inout parameter}}
+  }
+}
+
+var _count: Int = 0
+
+enum Color {
+  case red
+  case green
+  case blue
+
+  var count: Int {
+    borrow {
+      return _count
+    }
+    mutate {
+      return &_count
+    }
+  }
+}
+
+class KlassWrapper {
+  var _k: Klass
+
+  init(_ k: Klass) {
+    self._k = k
+  }
+
+  var k: Klass {
+    borrow {// expected-error{{a 'borrow' accessor is supported only on a struct or enum}}
+      return _k
+    }
+    mutate {// expected-error{{a 'mutate' accessor is supported only on a struct or enum}}
+      return &_k
+    }
+  }
+}
+
diff --git a/test/Parse/confusables.swift b/test/Parse/confusables.swift
index a7d8179c3e141..db799c29a82e3 100644
--- a/test/Parse/confusables.swift
+++ b/test/Parse/confusables.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // expected-error @+4 {{type annotation missing in pattern}}
 // expected-error @+3 {{cannot find operator '⁚' in scope}}
diff --git a/test/Parse/const.swift b/test/Parse/const.swift
index b169ec86216fa..e9ee4521d865a 100644
--- a/test/Parse/const.swift
+++ b/test/Parse/const.swift
@@ -21,12 +21,11 @@ func takeIntConst(@const _ a: Int) {}
 struct Article {
   let id: String
 }
-@const let keypath = \Article.id
+@const let keypath = \Article.id // expected-error{{keypaths not supported in a '@const' expression}}
 
 func LocalConstVarUser() -> Int {
   @const let localConst = 3
   return localConst + 1
 }
 
-// FIXME: This should be diagnosed
-@const let a: Bool = Bool.random()
+@const let a: Bool = Bool.random() // expected-error{{not supported in a '@const' expression}}
diff --git a/test/Parse/coroutine_accessors.swift b/test/Parse/coroutine_accessors.swift
index 66430049e2f9d..105d00544bf67 100644
--- a/test/Parse/coroutine_accessors.swift
+++ b/test/Parse/coroutine_accessors.swift
@@ -1,8 +1,8 @@
-// RUN: %target-typecheck-verify-swift \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated \
 // RUN:     -verify-additional-prefix enabled- \
 // RUN:     -enable-experimental-feature CoroutineAccessors \
 // RUN:     -debug-diagnostic-names
-// RUN: %target-typecheck-verify-swift \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated \
 // RUN:     -verify-additional-prefix disabled- \
 // RUN:     -debug-diagnostic-names
 
diff --git a/test/Parse/diagnose_availability_windows.swift b/test/Parse/diagnose_availability_windows.swift
index b171eb538aa70..d96c5be412263 100644
--- a/test/Parse/diagnose_availability_windows.swift
+++ b/test/Parse/diagnose_availability_windows.swift
@@ -29,7 +29,7 @@ windows10()
 // expected-note@-1 {{add 'if #available' version check}}
 
 func conditional_compilation() {
-  // expected-note@-1 {{add @available attribute to enclosing global function}}
+  // expected-note@-1 {{add '@available' attribute to enclosing global function}}
   if #available(Windows 10, *) {
     windows10() // OK
   } else {
diff --git a/test/Parse/diagnose_dynamicReplacement.swift b/test/Parse/diagnose_dynamicReplacement.swift
index 07ab5d1582a52..cc9ff76aae305 100644
--- a/test/Parse/diagnose_dynamicReplacement.swift
+++ b/test/Parse/diagnose_dynamicReplacement.swift
@@ -16,5 +16,5 @@ func test_dynamic_replacement_for2() {
 
 @_dynamicReplacement(for: dynamically_replaceable() // expected-note {{to match this opening '('}}
 func test_dynamic_replacement_for3() {
-// expected-error@-1 {{expected ')' after function name for @_dynamicReplacement}}
+// expected-error@-1 {{expected ')' after function name for '@_dynamicReplacement'}}
 }
diff --git a/test/Parse/enum.swift b/test/Parse/enum.swift
index 20718eb71334b..6455cf7859550 100644
--- a/test/Parse/enum.swift
+++ b/test/Parse/enum.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 enum Empty {}
 
diff --git a/test/Parse/enum_floating_point_raw_value.swift b/test/Parse/enum_floating_point_raw_value.swift
index 8444770d30ac4..79db4d7c9affb 100644
--- a/test/Parse/enum_floating_point_raw_value.swift
+++ b/test/Parse/enum_floating_point_raw_value.swift
@@ -1,12 +1,12 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // FIXME: this test only passes on platforms which have Float80.
 // <rdar://problem/19508460> Floating point enum raw values are not portable
 
 // REQUIRES: CPU=i386 || CPU=x86_64
 
-// Windows does not support FP80
-// XFAIL: OS=windows-msvc
+// Windows and Android do not support FP80
+// UNSUPPORTED: OS=windows-msvc, OS=linux-android
 
 enum RawTypeWithFloatValues : Float { // expected-error {{'RawTypeWithFloatValues' declares raw type 'Float', but does not conform to RawRepresentable and conformance could not be synthesized}} expected-note {{add stubs for conformance}}
   case Northrup = 1.5
diff --git a/test/Parse/execution.swift b/test/Parse/execution.swift
deleted file mode 100644
index 18d5a9e51ea00..0000000000000
--- a/test/Parse/execution.swift
+++ /dev/null
@@ -1,56 +0,0 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature ExecutionAttribute
-
-// REQUIRES: concurrency
-// REQUIRES: swift_feature_ExecutionAttribute
-
-typealias F = @execution(concurrent) () async -> Void
-
-typealias E = @execution(concurrent) () -> Void
-// expected-error@-1 {{cannot use '@execution' on non-async function type}}
-
-func test1(_: @execution(caller) (Int...) async -> Void) {}
-func test2(_: @execution(concurrent) (Int...) async -> Void) {}
-
-func test_err1_concurrent(_: @execution(concurrent) @MainActor () async -> Void) {}
-// expected-error@-1 {{cannot use '@execution' because function type is isolated to a global actor 'MainActor'}}
-
-func test_err1_caller(_: @execution(caller) @MainActor () async -> Void) {}
-// expected-error@-1 {{cannot use '@execution' because function type is isolated to a global actor 'MainActor'}}
-
-func test_err2_concurrent(_: @execution(concurrent) @isolated(any) () async -> Void) {}
-// expected-error@-1 {{cannot use '@execution' together with @isolated(any)}}
-
-func test_err2_caller(_: @execution(caller) @isolated(any) () async -> Void) {}
-// expected-error@-1 {{cannot use '@execution' together with @isolated(any)}}
-
-func test_err3_concurrent(_: @execution(concurrent) (isolated (any Actor)?) async -> Void) {}
-// expected-error@-1 {{cannot use '@execution' together with an isolated parameter}}
-
-func test_err3_caller(_: @execution(caller) (isolated (any Actor)?) async -> Void) {}
-// expected-error@-1 {{cannot use '@execution' together with an isolated parameter}}
-
-func test_err4(_: @execution (Int) -> Void) {}
-// expected-error@-1 {{expected 'concurrent' or 'caller' as the execution behavior}}
-// expected-error@-2 {{expected parameter type following ':'}}
-
-func test_err5(_: @execution( () async -> Void) {}
-// expected-error@-1 {{expected 'concurrent' or 'caller' as the execution behavior}}
-// expected-note@-2 {{to match this opening '('}}
-// expected-error@-3 {{expected ')' after execution behavior}}
-
-func test_err6(_: @execution(hello) () async -> Void) {}
-// expected-error@-1 {{expected 'concurrent' or 'caller' as the execution behavior}}
-
-func test_err7(_: @execution(hello () async -> Void) {}
-// expected-error@-1 {{expected 'concurrent' or 'caller' as the execution behavior}}
-// expected-note@-2 {{to match this opening '('}}
-// expected-error@-3 {{expected ')' after execution behavior}}
-
-func test_err8(_: @execution(concurrent) Int) {} // expected-error {{attribute does not apply to type}}
-
-do {
-  let _ = [@execution(caller) () async -> Void]()
-  let _ = [@execution(caller) () -> Void]()
-  // expected-error@-1 {{cannot use '@execution' on non-async function type}}
-}
-
diff --git a/test/Parse/execution_behavior_attrs.swift b/test/Parse/execution_behavior_attrs.swift
new file mode 100644
index 0000000000000..6f0a1035ff6c0
--- /dev/null
+++ b/test/Parse/execution_behavior_attrs.swift
@@ -0,0 +1,86 @@
+// RUN: %target-typecheck-verify-swift -disable-availability-checking
+
+// REQUIRES: concurrency
+
+typealias F = @concurrent () async -> Void
+
+typealias E = @concurrent () -> Void
+// expected-error@-1 {{cannot use '@concurrent' on non-async function type}}
+
+func test1(_: nonisolated(nonsending) (Int...) async -> Void) {}
+func test2(_: @concurrent (Int...) async -> Void) {}
+
+func test_err1_concurrent(_: @concurrent @MainActor () async -> Void) {}
+// expected-error@-1 {{cannot use '@concurrent' because function type is isolated to a global actor 'MainActor'}}
+
+func test_err1_caller(_: nonisolated(nonsending) @MainActor () async -> Void) {}
+// expected-error@-1 {{cannot use 'nonisolated(nonsending)' because function type is isolated to a global actor 'MainActor'}}
+
+func test_err2_concurrent(_: @concurrent @isolated(any) () async -> Void) {}
+// expected-error@-1 {{cannot use '@concurrent' together with '@isolated(any)'}}
+
+func test_err2_caller(_: nonisolated(nonsending) @isolated(any) () async -> Void) {}
+// expected-error@-1 {{cannot use 'nonisolated(nonsending)' together with '@isolated(any)'}}
+
+func test_err3_concurrent(_: @concurrent (isolated (any Actor)?) async -> Void) {}
+// expected-error@-1 {{cannot use '@concurrent' together with an isolated parameter}}
+
+func test_err3_caller(_: nonisolated(nonsending) (isolated (any Actor)?) async -> Void) {}
+// expected-error@-1 {{cannot use 'nonisolated(nonsending)' together with an isolated parameter}}
+
+func test_err4(_: nonisolated (Int) -> Void) {}
+// expected-error@-1 {{expected 'nonsending' in modifier}}
+// expected-error@-2 {{expected '{' in body of function declaration}}
+// expected-warning@-3 {{extraneous whitespace between attribute name and '('; this is an error in the Swift 6 language mode}}
+// expected-error@-4 {{consecutive statements on a line must be separated by ';'}}
+// expected-error@-5 {{expected expression}}
+
+func test_err5(_: nonisolated( () async -> Void) {}
+// expected-error@-1 {{expected 'nonsending' in modifier}}
+
+func test_err6(_: nonisolated(hello) () async -> Void) {}
+// expected-error@-1 {{expected 'nonsending' in modifier}}
+// expected-error@-2 {{cannot have more than one parameter list}}
+// expected-error@-3 {{cannot find type 'hello' in scope}}
+// expected-error@-4 {{onsecutive statements on a line must be separated by ';'}}
+// expected-error@-5 {{expected expression}}
+
+func test_err7(_: nonisolated(hello () async -> Void) {}
+// expected-error@-1 {{expected 'nonsending' in modifier}}
+// expected-error@-2 {{cannot find type 'hello' in scope}}
+
+func test_err8(_: @concurrent Int) {} // expected-error {{attribute does not apply to type}}
+
+do {
+  let _ = [nonisolated(nonsending) () async -> Void]()
+  let _ = [nonisolated(nonsending) () -> Void]()
+  // expected-error@-1 {{cannot use 'nonisolated(nonsending)' on non-async function type}}
+}
+
+protocol P {}
+
+struct S : nonisolated
+             P { // Ok
+}
+
+do {
+  func nonisolated() {}
+
+  // `nonisolated` is parsed as a function call
+  nonisolated // expected-error {{function is unused}}
+  (42) // expected-warning {{integer literal is unused}}
+
+  let _: nonisolated // expected-error {{cannot find type 'nonisolated' in scope}}
+    (Int) async -> Void // expected-error {{expected member name or initializer call after type name}}
+  // expected-note@-1 {{use '.self' to reference the type object}}
+  // expected-warning@-2 {{expression of type '((Int) async -> Void).Type' is unused}}
+
+  _ = [nonisolated()]
+}
+
+do {
+  func nonisolated(_: Int) -> Int { 42 }
+
+  nonisolated(0) // expected-warning {{result of call to 'nonisolated' is unused}}
+  print("hello")
+}
diff --git a/test/Parse/fixed_infinite_loops.swift b/test/Parse/fixed_infinite_loops.swift
index 711559b4c718b..c0745ac22e12a 100644
--- a/test/Parse/fixed_infinite_loops.swift
+++ b/test/Parse/fixed_infinite_loops.swift
@@ -1,10 +1,10 @@
 // RUN: %target-swift-frontend -parse -verify %s
 
 func test1() {
-  @s // expected-error {{expected statement}}
-  return
+  @s
+  return // expected-error {{expected declaration}}
 }
 func test2() {
-  @unknown // expected-error {{expected statement}}
-  return
+  @unknown // expected-error {{unknown attribute 'unknown'}}
+  return // expected-error {{expected declaration}}
 }
diff --git a/test/Parse/generic_disambiguation.swift b/test/Parse/generic_disambiguation.swift
index bcada136169a0..7a7fbe5459bec 100644
--- a/test/Parse/generic_disambiguation.swift
+++ b/test/Parse/generic_disambiguation.swift
@@ -1,7 +1,7 @@
 // RUN: %target-typecheck-verify-swift -verify-additional-prefix swift5-
 // RUN: %target-typecheck-verify-swift -swift-version 6 -verify-additional-prefix swift6-
 
-struct A<B> { // expected-note{{generic type 'A' declared here}}
+struct A<B> { // expected-note{{generic struct 'A' declared here}}
   init(x:Int) {}
   static func c() {}
 
diff --git a/test/Parse/identifiers.swift b/test/Parse/identifiers.swift
index 7971687dc4f9a..20ac28629be30 100644
--- a/test/Parse/identifiers.swift
+++ b/test/Parse/identifiers.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 func my_print<T>(_ t: T) {}
 
diff --git a/test/Parse/if-else-invalid.swift b/test/Parse/if-else-invalid.swift
new file mode 100644
index 0000000000000..9f015ee078ab2
--- /dev/null
+++ b/test/Parse/if-else-invalid.swift
@@ -0,0 +1,44 @@
+// RUN: %target-swift-frontend -parse -verify %s
+
+// No more diags expected during Sema.
+// RUN: %target-typecheck-verify-swift
+
+do {
+  func something() -> Bool {}
+  func foo() {}
+
+  do {
+    if something() {
+    // expected-error@+1:11 {{expected '{' or 'if' after 'else'}}{{none}}
+    } else
+  }
+
+  do {
+    if something() {
+    // expected-error@+1:11 {{expected '{' or 'if' after 'else'}}{{none}}
+    } else
+    foo()
+  }
+
+  do {
+    if something() {
+    // expected-error@+1:7 {{expected '{' or 'if' after 'else'; did you mean to write 'if'?}}{{11-11= if}}
+    } else something() { // Fix-it because all on one line.
+    }
+  }
+
+  do {
+    if something() {
+    // expected-error@+1:12 {{expected '{' or 'if' after 'else'}}{{none}}
+    } else something()
+    {
+    }
+  }
+
+ do {
+    if something() {
+    // expected-error@+1:12 {{expected '{' or 'if' after 'else'}}{{none}}
+    } else something()
+    foo1()
+  }
+}
diff --git a/test/Parse/invalid.swift b/test/Parse/invalid.swift
index e886233d6e5c3..766c4e52fc2df 100644
--- a/test/Parse/invalid.swift
+++ b/test/Parse/invalid.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 // REQUIRES: swift_swift_parser
 // FIXME: Swift parser is not enabled on Linux CI yet.
 // REQUIRES: OS=macosx
@@ -119,7 +119,7 @@ prefix func %<T>(x: T) -> T { return x } // No error expected - the < is conside
 
 struct Weak<T: class> { // expected-error {{'class' constraint can only appear on protocol declarations}}
   // expected-note@-1 {{did you mean to write an 'AnyObject' constraint?}} {{16-21=AnyObject}}
-  weak let value: T // expected-error {{'weak' must be a mutable variable, because it may change at runtime}} expected-error {{'weak' variable should have optional type 'T?'}} expected-error {{'weak' must not be applied to non-class-bound 'T'; consider adding a protocol conformance that has a class bound}}
+  weak let value: T // expected-error {{'weak' variable should have optional type 'T?'}} expected-error {{'weak' must not be applied to non-class-bound 'T'; consider adding a protocol conformance that has a class bound}}
 }
 
 let x: () = ()
diff --git a/test/Parse/library_evolution_feature.swift b/test/Parse/library_evolution_feature.swift
new file mode 100644
index 0000000000000..f2a34b40fd543
--- /dev/null
+++ b/test/Parse/library_evolution_feature.swift
@@ -0,0 +1,6 @@
+// RUN: %target-typecheck-verify-swift -enable-library-evolution
+
+#if hasFeature(LibraryEvolution)
+#else
+#error("Missing feature")
+#endif
diff --git a/test/Parse/lifetime_attr.swift b/test/Parse/lifetime_attr.swift
index f7cb627a89436..d679b0c4b6a32 100644
--- a/test/Parse/lifetime_attr.swift
+++ b/test/Parse/lifetime_attr.swift
@@ -1,17 +1,17 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature LifetimeDependence 
+// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature Lifetimes 
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct E {}
 
 struct NE : ~Escapable {}
 
-@lifetime(copy ne)
+@_lifetime(copy ne)
 func derive(_ ne: NE) -> NE {
   ne
 }
 
-@lifetime(borrow ne1, copy ne2)
+@_lifetime(borrow ne1, copy ne2)
 func derive(_ ne1: NE, _ ne2: NE) -> NE {
   if (Int.random(in: 1..<100) < 50) {
     return ne1
@@ -19,17 +19,17 @@ func derive(_ ne1: NE, _ ne2: NE) -> NE {
   return ne2
 }
 
-@lifetime // expected-error{{expected '(' after lifetime dependence specifier}}
-func testMissingLParenError(_ ne: NE) -> NE { // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+@_lifetime // expected-error{{expected '(' after lifetime dependence specifier}}
+func testMissingLParenError(_ ne: NE) -> NE { // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
   ne
 }
 
-@lifetime() // expected-error{{expected identifier, index or self in lifetime dependence specifier}}
-func testMissingDependence(_ ne: NE) -> NE { // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+@_lifetime() // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier, index or 'self' in lifetime dependence specifier}}
+func testMissingDependence(_ ne: NE) -> NE { // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
   ne
 }
 
-@lifetime(borrow borrow)
+@_lifetime(borrow borrow)
 func testNameConflict(_ borrow: E) -> NE {
   NE()
 }
diff --git a/test/Parse/line-directive.swift b/test/Parse/line-directive.swift
index f6080333746a4..4d3dde1c44e4a 100644
--- a/test/Parse/line-directive.swift
+++ b/test/Parse/line-directive.swift
@@ -84,3 +84,6 @@ class I55049 {
 // expected-error@+1 {{#line directive was renamed to #sourceLocation}}
 #line 1_000 "issue-55049.swift"
 class I55049_1 {}
+
+#sourceLocation
+(file: "nextLine.swift", line: 400) // expected-warning {{expression of type '(file: String, line: Int)' is unused}}
diff --git a/test/Parse/objc_enum.swift b/test/Parse/objc_enum.swift
index 558a605e19e25..b6c5237daf2b4 100644
--- a/test/Parse/objc_enum.swift
+++ b/test/Parse/objc_enum.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-objc-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-objc-interop
 
 @objc enum Foo: Int32 {
   case Zim, Zang, Zung
diff --git a/test/Parse/original_defined_in_attr.swift b/test/Parse/original_defined_in_attr.swift
index c5c114ab3afbb..f6d133cbfe126 100644
--- a/test/Parse/original_defined_in_attr.swift
+++ b/test/Parse/original_defined_in_attr.swift
@@ -4,7 +4,7 @@
 @_originallyDefinedIn(module: "foo", OSX 13.13) // expected-error {{'@_originallyDefinedIn' requires that 'foo()' have explicit availability for macOS}}
 public func foo() {}
 
-@_originallyDefinedIn(modulename: "foo", OSX 13.13) // expected-error {{expected 'module: "original"' in the first argument to @_originallyDefinedIn}}
+@_originallyDefinedIn(modulename: "foo", OSX 13.13) // expected-error {{expected 'module: "original"' in the first argument to '@_originallyDefinedIn'}}
 public func foo1() {}
 
 @_originallyDefinedIn(module: "foo", OSX 13.13.3) // expected-warning {{'@_originallyDefinedIn' only uses major and minor version number}}
@@ -14,7 +14,7 @@ public class ToplevelClass {}
 @_originallyDefinedIn(module: "foo") // expected-error {{expected at least one platform version in '@_originallyDefinedIn' attribute}}
 public class ToplevelClass1 {}
 
-@_originallyDefinedIn(OSX 13.13.3) // expected-error {{expected 'module: "original"' in the first argument to @_originallyDefinedIn}}
+@_originallyDefinedIn(OSX 13.13.3) // expected-error {{expected 'module: "original"' in the first argument to '@_originallyDefinedIn'}}
 public class ToplevelClass2 {}
 
 @_originallyDefinedIn(module: "foo",
@@ -50,3 +50,20 @@ fileprivate class ToplevelClass7 {}
 @available(OSX 13.10, *)
 @_originallyDefinedIn(module: "foo", OSX 13.13, iOS 7.0) // expected-warning {{'@_originallyDefinedIn' does not have any effect on internal declarations}}
 internal class ToplevelClass8 {}
+
+@available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+@_originallyDefinedIn(module: "foo", macOS 16, iOS 19, watchOS 12, tvOS 19, visionOS 3)
+public class ToplevelClass9 {}
+
+@available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+@_originallyDefinedIn(module: "foo", macOS 17, iOS 20, watchOS 13, tvOS 20, visionOS 4)
+// expected-warning@-1 {{'17' is not a valid version number for macOS}}
+// expected-warning@-2 {{'20' is not a valid version number for iOS}}
+// expected-warning@-3 {{'13' is not a valid version number for watchOS}}
+// expected-warning@-4 {{'20' is not a valid version number for tvOS}}
+// expected-warning@-5 {{'4' is not a valid version number for visionOS}}
+public class ToplevelClass10 {}
+
+@available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+@_originallyDefinedIn(module: "foo", macOS 26, iOS 26, watchOS 26, tvOS 26, visionOS 26)
+public class ToplevelClass11 {}
diff --git a/test/Parse/pointer_conversion.swift.gyb b/test/Parse/pointer_conversion.swift.gyb
index 9e2efd2b1094d..9a122f4edb357 100644
--- a/test/Parse/pointer_conversion.swift.gyb
+++ b/test/Parse/pointer_conversion.swift.gyb
@@ -1,13 +1,13 @@
 // RUN: %empty-directory(%t)
 
 // RUN: %gyb -DOPT_KIND=None %s -o %t/pointer_conversion.swift
-// RUN: %line-directive %t/pointer_conversion.swift -- %target-swift-frontend -typecheck -verify %t/pointer_conversion.swift
+// RUN: %line-directive %t/pointer_conversion.swift -- %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/pointer_conversion.swift
 
 // RUN: %gyb -DOPT_KIND=Optional %s -o %t/pointer_conversion_opt.swift
-// RUN: %line-directive %t/pointer_conversion_opt.swift -- %target-swift-frontend -typecheck -verify %t/pointer_conversion_opt.swift
+// RUN: %line-directive %t/pointer_conversion_opt.swift -- %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/pointer_conversion_opt.swift
 
 // RUN: %gyb -DOPT_KIND=ImplicitlyUnwrappedOptional %s -o %t/pointer_conversion_iuo.swift
-// RUN: %line-directive %t/pointer_conversion_iuo.swift -- %target-swift-frontend -typecheck -verify %t/pointer_conversion_iuo.swift
+// RUN: %line-directive %t/pointer_conversion_iuo.swift -- %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/pointer_conversion_iuo.swift
 
 %{
 if OPT_KIND == 'Optional':
diff --git a/test/Parse/recovery.swift b/test/Parse/recovery.swift
index c44dcc08ed60c..c79310410deda 100644
--- a/test/Parse/recovery.swift
+++ b/test/Parse/recovery.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 //===--- Helper types used in this file.
 
@@ -210,8 +210,10 @@ func missingControllingExprInForEach() {
 // The #if block is used to provide a scope for the for stmt to force it to end
 // where necessary to provoke the crash.
 #if true  // <rdar://problem/21679557> compiler crashes on "for{{"
-  // expected-error @+2 {{expected pattern}}
-  // expected-error @+1 {{expected Sequence expression for for-each loop}}
+  // expected-error @+4 {{expected pattern}}
+  // expected-error @+3 {{expected Sequence expression for for-each loop}}
+  // expected-error @+2 {{closure expression is unused}}
+  // expected-note @+1 {{did you mean to use a 'do' statement?}}
   for{{ // expected-note 2 {{to match this opening '{'}}
 #endif  // expected-error {{expected '}' at end of closure}} expected-error {{expected '}' at end of brace statement}}
 
@@ -548,7 +550,8 @@ func exprPostfix2() {
 
 class ExprSuper {
   init() {
-    super. // expected-error {{expected member name following '.'}} 
+    super. // expected-error {{expected member name following '.'}}
+    // expected-error@-1 {{'super' cannot be used in class 'ExprSuper' because it has no superclass}}
   }
 }
 
diff --git a/test/Parse/sending.swift b/test/Parse/sending.swift
index 3080e5b11c026..4e948cbd705dd 100644
--- a/test/Parse/sending.swift
+++ b/test/Parse/sending.swift
@@ -1,6 +1,5 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature SendingArgsAndResults -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
+// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature SendingArgsAndResults -strict-concurrency=complete
 
-// REQUIRES: swift_feature_RegionBasedIsolation
 // REQUIRES: swift_feature_SendingArgsAndResults
 
 func testArg(_ x: sending String) {
diff --git a/test/Parse/subscripting.swift b/test/Parse/subscripting.swift
index d28c5e6f4ba78..93eece26ed7e7 100644
--- a/test/Parse/subscripting.swift
+++ b/test/Parse/subscripting.swift
@@ -142,7 +142,7 @@ struct A2 {
   subscript (i : Int) -> // expected-error{{expected subscripting element type}}
      {
     get {
-      return stored
+      return stored // expected-error {{cannot find 'stored' in scope}}
     }
     set {
       stored = newValue // expected-error{{cannot find 'stored' in scope}}
diff --git a/test/Parse/switch.swift b/test/Parse/switch.swift
index 78801b1b44b00..b181bfbaa1c56 100644
--- a/test/Parse/switch.swift
+++ b/test/Parse/switch.swift
@@ -200,10 +200,10 @@ switch t {
 case (var a, 2), (1, _): // expected-error {{'a' must be bound in every pattern}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
   ()
 
-case (_, 2), (var a, _): // expected-error {{'a' must be bound in every pattern}}
+case (_, 2), (var a, _): // expected-error {{'a' must be bound in every pattern}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
   ()
 
-case (var a, 2), (1, var b): // expected-error {{'a' must be bound in every pattern}} expected-error {{'b' must be bound in every pattern}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
+case (var a, 2), (1, var b): // expected-error {{'a' must be bound in every pattern}} expected-error {{'b' must be bound in every pattern}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}} expected-warning {{variable 'b' was never used; consider replacing with '_' or removing it}}
   ()
 
 case (var a, 2): // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{17-17= break}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
@@ -221,7 +221,7 @@ case (1, var b): // expected-warning {{variable 'b' was never used; consider rep
 case (1, let b): // let bindings expected-warning {{immutable value 'b' was never used; consider replacing with '_' or removing it}}
   ()
 
-case (_, 2), (let a, _): // expected-error {{'a' must be bound in every pattern}} expected-warning {{case is already handled by previous patterns; consider removing it}}
+case (_, 2), (let a, _): // expected-error {{'a' must be bound in every pattern}} expected-warning {{case is already handled by previous patterns; consider removing it}} expected-warning {{immutable value 'a' was never used; consider replacing with '_' or removing it}}
   ()
 
 // OK
diff --git a/test/Parse/trailing-comma.swift b/test/Parse/trailing-comma.swift
index 4ba1af9eaa4cb..453c3388f9eaa 100644
--- a/test/Parse/trailing-comma.swift
+++ b/test/Parse/trailing-comma.swift
@@ -9,6 +9,10 @@ let values: [Int,] = [] // expected-note {{to match this opening '['}} expected-
 // Tuple and Tuple Pattern
 
 let _ = (a: 1, b: 2, c: 3,)
+let _: (a: Int, b: Int, c: Int,) = (a: 1, b: 2, c: 3,)
+
+// Closures
+let _: (String, Int, Float,) -> Void
 
 let (_, _,) = (0,1,)
 
@@ -34,7 +38,7 @@ struct S<T1, T2,> { }
 
 func foo<T1, T2,>() { }
 
-protocol P<T1, T2> {
+protocol P<T1, T2,> {
     associatedtype T1
     associatedtype T2
 }
@@ -60,6 +64,7 @@ struct S {
 // String Literal Interpolation
 
 "\(1,)"
+"\(1, f:)" // expected-error {{expected expression in list of expressions}}
 
 // Availability Spec List
 
@@ -87,7 +92,7 @@ struct Foo {
   var y: Int
   
   var value: (Int, Int) {
-    @storageRestrictions(initializes: x, y,)  // expected-error {{expected property name in @storageRestrictions list}}
+    @storageRestrictions(initializes: x, y,)  // expected-error {{expected property name in '@storageRestrictions' list}}
     init(initialValue) {
       self.x = initialValue.0
       self.y = initialValue.1
@@ -97,7 +102,7 @@ struct Foo {
 
 }
 
-func f(in: @differentiable(reverse,) (Int) -> Int) { } // expected-warning {{@differentiable' has been renamed to '@differentiable(reverse)' and will be removed in the next release}} expected-error {{unexpected ',' separator}} expected-error {{expected ',' separator}} expected-error {{unnamed parameters must be written with the empty name '_'}} 
+func f(in: @differentiable(reverse,) (Int) -> Int) { } // expected-warning {{@differentiable' has been renamed to '@differentiable(reverse)' and will be removed in the next release}} expected-error {{expected ',' separator}} expected-error {{unnamed parameters must be written with the empty name '_'}}
 
 @derivative(of: Self.other,) // expected-error {{unexpected ',' separator}}
 func foo() {}
@@ -134,4 +139,12 @@ if true, { } // expected-error {{expected '{' after 'if' condition}}
 
 guard true, else { } // expected-error {{expected expression in conditional}} 
 
-while true, { } // expected-error {{expected '{' after 'while' condition}} 
\ No newline at end of file
+while true, { } // expected-error {{expected '{' after 'while' condition}} 
+
+if #available(OSX 51,) { // expected-error {{expected platform name}}
+}
+
+@available(OSX 10.7, iOS 7.0, *,) // expected-error {{expected platform name}} expected-error {{expected declaration}}
+@_originallyDefinedIn(module: "HighLevel", OSX 10.9, iOS 13.0,) // expected-error {{unexpected ',' separator}}
+@backDeployed(before: OSX 10.9,) // expected-error {{unexpected ',' separator}}
+public struct StructWithAvailability {}
diff --git a/test/Parse/try.swift b/test/Parse/try.swift
index b79f36f8150e9..8b2df406d437d 100644
--- a/test/Parse/try.swift
+++ b/test/Parse/try.swift
@@ -237,12 +237,14 @@ struct ThingProducer {
 }
 
 let optProducer: ThingProducer? = ThingProducer()
-let _: Int? = try? optProducer?.produceInt() // expected-error {{value of optional type 'Int??' not unwrapped; did you mean to use 'try!' or chain with '?'?}}
+let _: Int? = try? optProducer?.produceInt() // expected-error {{cannot assign value of type 'Int??' to type 'Int?'}}
+// expected-note@-1 {{arguments to generic parameter 'Wrapped' ('Int?' and 'Int') are expected to be equal}}
 let _: Int = try? optProducer?.produceInt() // expected-error {{cannot convert value of type 'Int??' to specified type 'Int'}}
 let _: String = try? optProducer?.produceInt() // expected-error {{cannot convert value of type 'Int??' to specified type 'String'}}
 let _: Int?? = try? optProducer?.produceInt() // good
 
-let _: Int? = try? optProducer?.produceIntNoThrowing() // expected-error {{value of optional type 'Int??' not unwrapped; did you mean to use 'try!' or chain with '?'?}}
+let _: Int? = try? optProducer?.produceIntNoThrowing() // expected-error {{cannot assign value of type 'Int??' to type 'Int?'}}
+// expected-note@-1 {{arguments to generic parameter 'Wrapped' ('Int?' and 'Int') are expected to be equal}}
 let _: Int?? = try? optProducer?.produceIntNoThrowing() // expected-warning {{no calls to throwing functions occur within 'try' expression}}
 
 let _: Int? = (try? optProducer?.produceAny()) as? Int // good
diff --git a/test/Parse/type_expr.swift b/test/Parse/type_expr.swift
index 55ea4a084b12d..eb5ad76179445 100644
--- a/test/Parse/type_expr.swift
+++ b/test/Parse/type_expr.swift
@@ -313,24 +313,47 @@ func testFunctionCollectionTypes() {
   _ = [() -> Int]()
   _ = [(Int) -> ()]()
 
-  _ = 2 + () -> Int // expected-error {{expected type before '->'}}
-  _ = () -> (Int, Int).2 // expected-error {{expected type after '->'}}
+  // This is folded as '(2 + ()) -> Int'
+  _ = 2 + () -> Int
+  // expected-error@-1 {{expected type before '->'}}
+  // expected-error@-2 {{cannot convert value of type '()' to expected argument type 'Int'}}
+
+  _ = () -> (Int, Int).2
+  // expected-error@-1 {{expected type after '->'}}
+  // expected-error@-2 {{value of tuple type '(Int, Int)' has no member '2'}}
+
   _ = (Int) -> Int // expected-error {{expected member name or initializer call after type name}} expected-note{{use '.self' to reference the type object}}
 
   _ = @convention(c) () -> Int // expected-error{{expected member name or initializer call after type name}} expected-note{{use '.self' to reference the type object}}
   _ = 1 + (@convention(c) () -> Int).self // expected-error{{cannot convert value of type '(@convention(c) () -> Int).Type' to expected argument type 'Int'}}
-  _ = (@autoclosure () -> Int) -> (Int, Int).2 // expected-error {{expected type after '->'}}
+
+  _ = (@autoclosure () -> Int) -> (Int, Int).2
+  // expected-error@-1 {{expected type after '->'}}
+  // expected-error@-2 {{value of tuple type '(Int, Int)' has no member '2'}}
+
   _ = ((@autoclosure () -> Int) -> (Int, Int)).1 // expected-error {{type '(@autoclosure () -> Int) -> (Int, Int)' has no member '1'}}
   _ = ((inout Int) -> Void).self
 
   _ = [(Int) throws -> Int]()
   _ = [@convention(swift) (Int) throws -> Int]().count
   _ = [(inout Int) throws -> (inout () -> Void) -> Void]().count
-  _ = [String: (@autoclosure (Int) -> Int32) -> Void]().keys // expected-error {{argument type of @autoclosure parameter must be '()'}}
+  _ = [String: (@autoclosure (Int) -> Int32) -> Void]().keys // expected-error {{argument type of '@autoclosure' parameter must be '()'}}
   let _ = [(Int) -> throws Int]() // expected-error{{'throws' may only occur before '->'}}
   let _ = [Int throws Int](); // expected-error{{'throws' may only occur before '->'}} expected-error {{consecutive statements on a line must be separated by ';'}}
 }
 
+func testInvalidArrowWithClosure() {
+  _ = { undefined -> undefined2 }
+  // expected-error@-1 {{cannot find 'undefined' in scope}}
+  // expected-error@-2 {{cannot find 'undefined2' in scope}}
+  // expected-error@-3 {{expected type before '->'}}
+  // expected-error@-4 {{expected type after '->'}}
+
+  () -> { let x: Int = "" }
+  // expected-error@-1 {{expected type after '->'}}
+  // expected-error@-2 {{cannot convert value of type 'String' to specified type 'Int'}}
+}
+
 func compositionType() {
   _ = P1 & P2 // expected-error {{expected member name or initializer call after type name}} expected-note{{use '.self'}} {{7-7=(}} {{14-14=).self}}
   _ = any P1 & P1 // expected-error {{expected member name or initializer call after type name}} expected-note{{use '.self'}} {{7-7=(}} {{18-18=).self}}
diff --git a/test/Parse/using.swift b/test/Parse/using.swift
new file mode 100644
index 0000000000000..277447765652f
--- /dev/null
+++ b/test/Parse/using.swift
@@ -0,0 +1,72 @@
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature DefaultIsolationPerFile
+
+// REQUIRES: swift_feature_DefaultIsolationPerFile
+
+// REQUIRES: concurrency
+
+using @MainActor
+// expected-note@-1 {{default isolation was previously declared here}}
+
+using nonisolated
+// expected-error@-1 {{invalid redeclaration of file-level default actor isolation}}
+
+using @Test // expected-error {{default isolation can only be set to '@MainActor' or 'nonisolated'}}
+using test // expected-error {{default isolation can only be set to '@MainActor' or 'nonisolated'}}
+
+do {
+  using // expected-warning {{expression of type 'Int' is unused}}
+  @MainActor
+// expected-error@+1 {{expected declaration}}
+}
+
+do {
+  using // expected-warning {{expression of type 'Int' is unused}}
+  nonisolated // expected-error {{cannot find 'nonisolated' in scope}}
+}
+
+do {
+  func
+  using (x: Int) {}
+
+  using(x: 42)
+}
+
+do {
+  func
+  using
+  (x: Int) {}
+
+  using(x: 42)
+}
+
+let
+  using = 42
+
+let (x: Int, using: String) = (x: 42, using: "")
+
+do {
+  using @MainActor // expected-error {{declaration is only valid at file scope}}
+}
+
+func test() {
+  using @MainActor // expected-error {{declaration is only valid at file scope}}
+}
+
+struct S {
+  var x: Int {
+    using @MainActor // expected-error {{declaration is only valid at file scope}}
+  }
+
+  using @MainActor func test() {}
+  // expected-error@-1 {{declaration is only valid at file scope}}
+  // expected-error@-2 {{consecutive declarations on a line must be separated by ';'}}
+
+  using nonisolated subscript(a: Int) -> Bool { false }
+  // expected-error@-1 {{declaration is only valid at file scope}}
+  // expected-error@-2 {{consecutive declarations on a line must be separated by ';'}}
+}
+
+do {
+  @objc using @MainActor
+  // expected-error@-1 {{declaration is only valid at file scope}}
+}
diff --git a/test/PerformanceHints/array-ret.swift b/test/PerformanceHints/array-ret.swift
new file mode 100644
index 0000000000000..e016f5156f364
--- /dev/null
+++ b/test/PerformanceHints/array-ret.swift
@@ -0,0 +1,39 @@
+// RUN: %empty-directory(%t)
+
+// Ensure ignored by-default
+// RUN: %target-swift-frontend -typecheck %s -diagnostic-style llvm -verify
+
+// Ensure enabled with '-Wwarning'
+// RUN: %target-swift-frontend -typecheck %s -diagnostic-style llvm -Wwarning PerformanceHints &> %t/output_warn.txt
+// RUN: cat %t/output_warn.txt | %FileCheck %s -check-prefix CHECK-WARN
+// RUN: %target-swift-frontend -typecheck %s -diagnostic-style llvm -Wwarning ReturnTypeImplicitCopy &> %t/output_warn.txt
+// RUN: cat %t/output_warn.txt | %FileCheck %s -check-prefix CHECK-WARN
+
+// Ensure enabled with '-Werror' for the broad category and downgraded to warning for the subgroup with '-Wwarning'
+// RUN: %target-swift-frontend -typecheck %s -diagnostic-style llvm -Werror PerformanceHints -Wwarning ReturnTypeImplicitCopy &> %t/output_warn.txt
+// RUN: cat %t/output_warn.txt | %FileCheck %s -check-prefix CHECK-WARN
+
+// Ensure enabled with '-Wwarning' for the broad category and downgraded to warning for the subgroup with '-Werror'
+// RUN: not %target-swift-frontend -typecheck %s -diagnostic-style llvm -Wwarning PerformanceHints -Werror ReturnTypeImplicitCopy &> %t/output_err.txt
+// RUN: cat %t/output_err.txt | %FileCheck %s -check-prefix CHECK-ERR
+
+// Ensure escalated with '-Werror'
+// RUN: not %target-swift-frontend -typecheck %s -diagnostic-style llvm -Werror ReturnTypeImplicitCopy &> %t/output_err.txt
+// RUN: cat %t/output_err.txt | %FileCheck %s -check-prefix CHECK-ERR
+
+// CHECK-ERR: error: Performance: 'foo()' returns an array, leading to implicit copies. Consider using an 'inout' parameter instead. [#ReturnTypeImplicitCopy]
+// CHECK-ERR: error: Performance: closure returns an array, leading to implicit copies. Consider using an 'inout' parameter instead. [#ReturnTypeImplicitCopy]
+
+// CHECK-WARN: warning: Performance: 'foo()' returns an array, leading to implicit copies. Consider using an 'inout' parameter instead. [#ReturnTypeImplicitCopy]
+// CHECK-WARN: warning: Performance: closure returns an array, leading to implicit copies. Consider using an 'inout' parameter instead. [#ReturnTypeImplicitCopy]
+
+func foo() -> [Int] {
+    return [1,2,3,4,5,6]
+}
+
+func bar() -> Int {
+    let myCoolArray = { () -> [Int] in
+        return [1, 2]
+    }
+    return myCoolArray().count
+}
diff --git a/test/PerformanceHints/existential-any.swift b/test/PerformanceHints/existential-any.swift
new file mode 100644
index 0000000000000..910a0157cb224
--- /dev/null
+++ b/test/PerformanceHints/existential-any.swift
@@ -0,0 +1,264 @@
+// RUN: %target-typecheck-verify-swift -Werror ExistentialType
+
+protocol Animal {
+  var Name: String { get }
+}
+
+struct Tiger: Animal {
+  let Name: String = "Tiger"
+}
+
+struct Panda: Animal {
+  let Name: String = "Panda"
+}
+
+struct AnimalError: Error {
+  let reason: String
+
+  init(reason: String) {
+    self.reason = reason
+  }
+}
+
+struct Container<T> {
+  let value: T
+}
+
+protocol Person {
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Typealias
+///////////////////////////////////////////////////////////////////////////////
+
+typealias AnyAnimal = any Animal  // expected-error {{Performance: 'AnyAnimal' aliases an existential type, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+typealias AnimalContainer<T> = Container<any Animal>  // expected-error {{Performance: 'AnimalContainer' aliases an existential type, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+typealias AnimalHandler = (any Animal) -> (any Animal)?  // expected-error {{Performance: 'AnimalHandler' aliases an existential type, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+
+////////////////////////////////////////////////////////////////////////////////
+// Function Return Type
+///////////////////////////////////////////////////////////////////////////////
+
+// Regular
+func returnAnimal1() -> any Animal { return Tiger() }  // expected-error {{Performance: 'returnAnimal1()' returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+
+// Optional
+func returnAnimal2() -> (any Animal)? {  // expected-error {{Performance: 'returnAnimal2()' returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  let n = Int.random(in: 1...100)
+  return (n <= 50) ? nil : Tiger()
+}
+
+// Throwing
+func returnAnimal3() throws -> any Animal {  // expected-error {{Performance: 'returnAnimal3()' returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  let n = Int.random(in: 1...100)
+  if n <= 50 {
+    throw AnimalError(reason: "All animals are extinct.")
+  } else {
+    return Tiger()
+  }
+}
+
+// Async
+func returnAnimal4() async -> any Animal {}  // expected-error {{Performance: 'returnAnimal4()' returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+
+////////////////////////////////////////////////////////////////////////////////
+// Function Parameter Type
+///////////////////////////////////////////////////////////////////////////////
+
+// Regular parameters
+func animalParam1(_ animal: any Animal) {}  // expected-error {{Performance: 'animal' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead}}
+
+// Multiple parameters
+func animalParam2(
+  _ animal: any Animal,  // expected-error {{Performance: 'animal' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  to other: any Animal  // expected-error {{Performance: 'other' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+) {}
+
+// Variadic parameters
+func animalParam3(_ animals: any Animal...) {}  // expected-error {{Performance: 'animals' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+
+// In-out parameters
+func animalParam4(_ animal: inout any Animal) {}  // expected-error {{Performance: 'animal' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+
+////////////////////////////////////////////////////////////////////////////////
+// Protocol
+////////////////////////////////////////////////////////////////////////////////
+protocol AnimalShelter {
+  var animal: (any Animal)? {  // expected-error {{Performance: 'animal' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+    get  // expected-error {{Performance: getter for 'animal' returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  }
+  func admit(_ animal: any Animal)  // expected-error {{Performance: 'animal' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  func releaseAnimal() -> (any Animal)?  // expected-error {{Performance: 'releaseAnimal()' returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  subscript(id: String) -> (any Animal)? { get }  // expected-error {{Performance: getter for 'subscript(_:)' returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Constructor
+////////////////////////////////////////////////////////////////////////////////
+class Zoo {
+  var animals: [any Animal]  // expected-error {{Performance: 'animals' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+
+  init(with animal: any Animal) {  // expected-error {{Performance: 'animal' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+    self.animals = [animal]
+  }
+
+  init(animals: [any Animal]) {  // expected-error {{Performance: 'animals' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+    self.animals = animals
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Compound Types
+////////////////////////////////////////////////////////////////////////////////
+func testCompoundTypes() {
+  let animals1: [any Animal] = []  // expected-error {{Performance: 'animals1' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: animals1))
+
+  let animals2: [any Animal] = []  // expected-error {{Performance: 'animals2' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: animals2))
+
+  let animals3: [String: any Animal] = [:]  // expected-error {{Performance: 'animals3' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: animals3))
+
+  let animals4: [String: any Animal] = [:]  // expected-error {{Performance: 'animals4' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: animals4))
+
+  let animals5: (any Animal)? = nil  // expected-error {{Performance: 'animals5' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: animals5))
+
+  let animals6: (any Animal)? = nil  // expected-error {{Performance: 'animals6' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: animals6))
+
+  let animals7: Result<any Animal, Error> = .success(Tiger())  // expected-error {{Performance: 'animals7' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: animals7))
+
+  let container = Container<any Animal>(value: Tiger())  // expected-error {{Performance: 'container' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: container))
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Tuple
+////////////////////////////////////////////////////////////////////////////////
+func tupleTest() {
+  let _ = ([Tiger() as any Animal], [Panda() as any Animal])  // expected-error {{Performance: declaration uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+
+  let (
+    animalsA,  // expected-error {{Performance: 'animalsA' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+    animalsB  // expected-error {{Performance: 'animalsB' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  ) = ([Tiger() as any Animal], [Panda() as any Animal])
+  print(type(of: animalsA))
+  print(type(of: animalsB))
+
+  let (
+    _,  // expected-error {{Performance: declaration uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+    animalsC  // expected-error {{Performance: 'animalsC' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  ) = ([Tiger() as any Animal], [Panda() as any Animal])
+
+  print(type(of: animalsC))
+
+  let (_, _) = ([Tiger() as any Animal], [Panda() as any Animal])  // expected-error 2 {{Performance: declaration uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+
+  let tuple: (animal1: any Animal, animal2: any Animal) = (Tiger(), Panda())  // expected-error {{Performance: 'tuple' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: tuple))
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Closure
+////////////////////////////////////////////////////////////////////////////////
+func closureTest() {
+  // Closure parameter type
+  let handler: (any Animal) -> Void = {  // expected-error {{Performance: 'handler' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+    animal in print(type(of: animal))  // expected-error {{'animal' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  }
+  handler(Tiger())
+
+  // Closure return type
+  let factory: () -> any Animal = { Tiger() }  // expected-error {{Performance: 'factory' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}} expected-error {{Performance: closure returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: factory()))
+
+  // Both parameter and return types
+  let transformer: (any Animal) -> any Animal = { $0 }  // expected-error {{Performance: 'transformer' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}} expected-error {{Performance: closure returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: transformer(Tiger())))
+
+  // Escaping closures
+  var handlers: [(any Animal) -> Void] = []  // expected-error {{Performance: 'handlers' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  func registerHandler(with handler: @escaping (any Animal) -> Void) {  // expected-error {{Performance: 'handler' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+    handlers.append(handler)
+  }
+
+  // Autoclosure
+  func registerHandler2(animalThunk: @autoclosure () -> any Animal) {  // expected-error {{Performance: 'animalThunk' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+    handlers[0](animalThunk())
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Type casting
+///////////////////////////////////////////////////////////////////////////////
+protocol A {
+}
+
+protocol A1: A {
+}
+
+protocol A2: A {
+}
+
+struct S1: A1 {
+}
+
+struct S2: A2 {
+}
+
+func testTypeCasting() {
+  let randomNumber = Int.random(in: 1...100)
+
+  let value: any A = randomNumber <= 50 ? S1() : S2()  // expected-error {{Performance: 'value' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+
+  let a1 = value as? any A1  // expected-error {{Performance: 'a1' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: a1))
+
+  let a2 = value as! any A2  // expected-error {{Performance: 'a2' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  print(type(of: a2))
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Enum
+///////////////////////////////////////////////////////////////////////////////
+enum PetOwnership {
+  case owned(
+    pet: any Animal,  // expected-error {{Performance: 'pet' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+    owner: any Person)  // expected-error {{Performance: 'owner' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  case stray(any Animal)  // expected-error {{Performance: parameter uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  case multiple([any Animal])  // expected-error {{Performance: parameter uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// An existential in parent type
+///////////////////////////////////////////////////////////////////////////////
+struct Outer<T> {
+  struct Inner {}
+  var i = Inner()
+}
+
+func f() -> Outer<any Animal>.Inner {  // expected-error {{Performance: 'f()' returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  return Outer<any Animal>().i
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Implicit AST Nodes
+////////////////////////////////////////////////////////////////////////////////
+
+func stringPlusInReduce() {
+  let animalKinds = ["Tiger", "Panda", "Tiger", "Dodo"]
+  let animals: [any Animal] = // expected-error {{Performance: 'animals' uses an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+  animalKinds.map { animalKind in // expected-error {{Performance: closure returns an existential, leading to heap allocation, reference counting, and dynamic dispatch. Consider using generic constraints or concrete types instead.}}
+      switch animalKind {
+      case "Tiger":
+        return Tiger()
+      default:
+        return Panda()
+      }
+    }
+  print(animals)
+}
diff --git a/test/PrintAsObjC/availability_canonical_versions.swift b/test/PrintAsObjC/availability_canonical_versions.swift
new file mode 100644
index 0000000000000..ab21b5caca97d
--- /dev/null
+++ b/test/PrintAsObjC/availability_canonical_versions.swift
@@ -0,0 +1,47 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-module -o %t %s -disable-objc-attr-requires-foundation-module
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -parse-as-library %t/availability_canonical_versions.swiftmodule -typecheck -verify -emit-objc-header-path %t/availability.h -import-objc-header %S/../Inputs/empty.h -disable-objc-attr-requires-foundation-module
+// RUN: %FileCheck %s < %t/availability.h
+// RUN: %check-in-clang %t/availability.h
+
+// REQUIRES: objc_interop
+
+// CHECK-LABEL: @interface Availability{{$}}
+@objc class Availability {
+  // CHECK-NEXT: - (void)alwaysAvailable;
+  @objc func alwaysAvailable() {}
+
+  // CHECK-NEXT: - (void)introducedOn10_16
+  // CHECK-SAME: SWIFT_AVAILABILITY(ios,introduced=10.16)
+  // CHECK-SAME: SWIFT_AVAILABILITY(macos,introduced=11.0)
+  @available(macOS 10.16, *)
+  @available(iOS, introduced: 10.16)
+  @objc func introducedOn10_16() {}
+
+  // CHECK-NEXT: - (void)introducedOn11_0
+  // CHECK-SAME: SWIFT_AVAILABILITY(ios,introduced=11.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(macos,introduced=11.0)
+  @available(macOS 11.0, *)
+  @available(iOS, introduced: 11.0)
+  @objc func introducedOn11_0() {}
+
+  // CHECK-NEXT: - (void)introducedOnVersionsMappingTo26_0
+  // CHECK-SAME: SWIFT_AVAILABILITY(visionos,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(tvos,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(watchos,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(maccatalyst,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(ios,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(macos,introduced=26.0)
+  @available(macOS 16.0, iOS 19.0, macCatalyst 19.0, watchOS 12.0, tvOS 19.0, visionOS 3.0, *)
+  @objc func introducedOnVersionsMappingTo26_0() {}
+
+  // CHECK-NEXT: - (void)introducedOn26_0
+  // CHECK-SAME: SWIFT_AVAILABILITY(visionos,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(watchos,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(tvos,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(maccatalyst,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(ios,introduced=26.0)
+  // CHECK-SAME: SWIFT_AVAILABILITY(macos,introduced=26.0)
+  @available(macOS 26.0, iOS 26.0, macCatalyst 26.0, tvOS 26.0, watchOS 26.0, visionOS 26.0, *)
+  @objc func introducedOn26_0() {}
+}
diff --git a/test/PrintAsObjC/availability_custom_domains.swift b/test/PrintAsObjC/availability_custom_domains.swift
new file mode 100644
index 0000000000000..98c95d47d5b46
--- /dev/null
+++ b/test/PrintAsObjC/availability_custom_domains.swift
@@ -0,0 +1,232 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/func.h -DFUNC
+
+// RUN: %FileCheck %s --check-prefixes=CHECK-FUNC --input-file %t/func.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/func.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/class.h -DCLASS
+
+// RUN: %FileCheck %s --check-prefixes=CHECK-CLASS --input-file %t/class.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/class.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/class_member.h -DCLASS_MEMBER
+
+// RUN: %FileCheck %s --check-prefixes=CHECK-CLASS-MEMBER --input-file %t/class_member.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/class_member.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/protocol.h -DPROTOCOL
+
+// RUN: %FileCheck %s --check-prefixes=CHECK-PROTOCOL --input-file %t/protocol.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/protocol.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/protocol_member.h -DPROTOCOL_MEMBER
+
+// RUN: %FileCheck %s --check-prefixes=CHECK-PROTOCOL-MEMBER --input-file %t/protocol_member.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/protocol_member.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/extension.h -DEXTENSION
+
+// RUN: %FileCheck %s --check-prefixes=CHECK-EXTENSION --input-file %t/extension.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/extension.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/extension_member.h -DEXTENSION_MEMBER
+
+// RUN: %FileCheck %s --check-prefixes=CHECK-EXTENSION-MEMBER --input-file %t/extension_member.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/extension_member.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/enum.h -DENUM
+
+// RUN: %FileCheck %s --check-prefixes=CHECK-ENUM --input-file %t/enum.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/enum.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/enum_member.h -DENUM_MEMBER
+
+// RUN: %FileCheck %s --check-prefixes=CHECK-ENUM-MEMBER --input-file %t/enum_member.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/enum_member.h
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck \
+// RUN:   -verify -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-objc-header %S/../Inputs/empty.h \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -emit-objc-header-path %t/private.h -DPRIVATE
+
+// RUN: %FileCheck %s --check-prefix=CHECK-PRIVATE --input-file %t/private.h
+// RUN: %check-in-clang -I %S/../Inputs/custom-modules/availability-domains %t/private.h
+
+// REQUIRES: swift_feature_CustomAvailability
+// REQUIRES: objc_interop
+
+import Oceans
+
+#if FUNC
+
+// CHECK-FUNC: SWIFT_EXTERN void arctic_func(void) SWIFT_NOEXCEPT SWIFT_AVAILABILITY_DOMAIN(Arctic,0);
+@available(Arctic)
+@_cdecl("arctic_func") func arcticFunc() { }
+
+#elseif CLASS
+
+// CHECK-CLASS: SWIFT_AVAILABILITY_DOMAIN(Arctic,0)
+// CHECK-CLASS-LABEL: @interface ArcticClass{{$}}
+@available(Arctic)
+@objc class ArcticClass {
+  // CHECK-CLASS-NEXT: - (void)alwaysAvailable;
+  @objc func alwaysAvailable() { }
+}
+// CHECK-CLASS-LABEL: @end
+
+#elseif CLASS_MEMBER
+
+// CHECK-CLASS-MEMBER-LABEL: @interface AvailableClass{{$}}
+@objc class AvailableClass {
+  // CHECK-CLASS-MEMBER-NEXT: - (void)availableInArctic SWIFT_AVAILABILITY_DOMAIN(Arctic,0);
+  @available(Arctic)
+  @objc func availableInArctic() { }
+
+  // CHECK-CLASS-MEMBER-NEXT: @property (nonatomic) NSInteger unavailableInArctic SWIFT_AVAILABILITY_DOMAIN(Arctic,1);
+  @available(Arctic, unavailable)
+  @objc var unavailableInArctic: Int {
+    get { 0 }
+    set { }
+  }
+}
+// CHECK-CLASS-MEMBER-LABEL: @end
+
+#elseif PROTOCOL
+
+// CHECK-PROTOCOL: SWIFT_AVAILABILITY_DOMAIN(Arctic,0)
+// CHECK-PROTOCOL-LABEL: @protocol ArcticProtocol{{$}}
+@available(Arctic)
+@objc protocol ArcticProtocol {
+  // CHECK-PROTOCOL-NEXT: - (void)requirement;
+  func requirement()
+}
+// CHECK-PROTOCOL-LABEL: @end
+
+#elseif PROTOCOL_MEMBER
+
+// CHECK-PROTOCOL-MEMBER-LABEL: @protocol AvailableProtocol{{$}}
+@objc protocol AvailableProtocol {
+  // CHECK-PROTOCOL-MEMBER-NEXT: - (void)availableInArctic SWIFT_AVAILABILITY_DOMAIN(Arctic,0);
+  @available(Arctic)
+  func availableInArctic()
+
+  func requirement()
+}
+// CHECK-PROTOCOL-MEMBER-LABEL: @end
+
+#elseif EXTENSION
+
+// CHECK-EXTENSION-LABEL: @interface AvailableClass{{$}}
+@objc class AvailableClass {
+}
+// CHECK-EXTENSION-LABEL: @end
+
+// CHECK-EXTENSION-LABEL: SWIFT_AVAILABILITY_DOMAIN(Arctic,0)
+// CHECK-EXTENSION-NEXT: @interface AvailableClass (SWIFT_EXTENSION(availability_custom_domains))
+@available(Arctic)
+extension AvailableClass {
+  // CHECK-EXTENSION-NEXT: - (void)alwaysAvailable;
+  @objc func alwaysAvailable() { }
+}
+// CHECK-EXTENSION-LABEL: @end
+
+#elseif EXTENSION_MEMBER
+
+// CHECK-EXTENSION-MEMBER-LABEL: @interface AvailableClass{{$}}
+@objc class AvailableClass {
+}
+// CHECK-EXTENSION-MEMBER-LABEL: @end
+
+// CHECK-EXTENSION-MEMBER-LABEL: @interface AvailableClass (SWIFT_EXTENSION(availability_custom_domains))
+extension AvailableClass {
+  // CHECK-EXTENSION-MEMBER-NEXT: - (void)availableInArctic SWIFT_AVAILABILITY_DOMAIN(Arctic,0);
+  @available(Arctic)
+  @objc func availableInArctic() { }
+}
+// CHECK-EXTENSION-MEMBER-LABEL: @end
+
+#elseif ENUM
+
+// FIXME: [availability] Availability attribute is missing
+// CHECK-ENUM-LABEL: typedef SWIFT_ENUM(NSInteger, ArcticEnum, closed)
+@available(Arctic)
+@objc enum ArcticEnum: Int {
+  // CHECK-ENUM-NEXT: ArcticEnumAvailable = 0,
+  case available
+}
+// CHECK-ENUM-NEXT: };
+
+#elseif ENUM_MEMBER
+
+// FIXME: [availability] Availability attribute is missing
+// CHECK-ENUM-MEMBER-LABEL: typedef SWIFT_ENUM(NSInteger, AvailableEnum, closed)
+@objc enum AvailableEnum: Int {
+  // CHECK-ENUM-MEMBER-NEXT: AvailableEnumAvailableInArctic = 0,
+  @available(Arctic)
+  case availableInArctic
+}
+// CHECK-ENUM-MEMBER-NEXT: };
+
+#elseif PRIVATE
+
+// CHECK-PRIVATE-NOT: @import Oceans;
+// CHECK-PRIVATE-NOT: @interface PrivateClass
+@available(Arctic)
+@objc private class PrivateClass { }
+
+// CHECK-PRIVATE-LABEL: @interface ClassWithPrivateMember{{$}}
+@objc class ClassWithPrivateMember {
+  // CHECK-PRIVATE-NOT: - (void)member;
+  @available(Arctic)
+  @objc private func member() { }
+}
+
+#endif
diff --git a/test/PrintAsObjC/availability_macosx_canonical_versions.swift b/test/PrintAsObjC/availability_macosx_canonical_versions.swift
deleted file mode 100644
index 164cbed53b109..0000000000000
--- a/test/PrintAsObjC/availability_macosx_canonical_versions.swift
+++ /dev/null
@@ -1,20 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-module -o %t %s -disable-objc-attr-requires-foundation-module
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -parse-as-library %t/availability_macosx_canonical_versions.swiftmodule -typecheck -verify -emit-objc-header-path %t/availability.h -import-objc-header %S/../Inputs/empty.h -disable-objc-attr-requires-foundation-module
-// RUN: %FileCheck %s < %t/availability.h
-// RUN: %check-in-clang %t/availability.h
-
-// REQUIRES: objc_interop
-
-// CHECK-LABEL: @interface Availability{{$}}
-// CHECK-NEXT: - (void)alwaysAvailable;
-// CHECK-NEXT: - (void)introducedOn10_16
-// CHECK-DAG: SWIFT_AVAILABILITY(macos,introduced=11.0)
-// CHECK-DAG: SWIFT_AVAILABILITY(ios,introduced=10.16)
-
-@objc class Availability {
-  @objc func alwaysAvailable() {}
-  @available(macOS 10.16, *)
-  @available(iOS, introduced: 10.16)
-  @objc func introducedOn10_16() {}
-}
diff --git a/test/PrintAsObjC/cdecl-enum-reference.swift b/test/PrintAsObjC/cdecl-enum-reference.swift
new file mode 100644
index 0000000000000..14687c4474689
--- /dev/null
+++ b/test/PrintAsObjC/cdecl-enum-reference.swift
@@ -0,0 +1,45 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+/// Build CoreLib defining a @c enum.
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   %t/CoreLib.swift -emit-module -verify -o %t \
+// RUN:   -emit-clang-header-path %t/CoreLib.h \
+// RUN:   -enable-experimental-feature CDecl
+// RUN: %check-in-clang-c %t/CoreLib.h -I %t
+
+/// Build MiddleLib using the @c enum in API.
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   %t/MiddleLib.swift -emit-module -verify -o %t -I %t \
+// RUN:   -emit-clang-header-path %t/MiddleLib.h \
+// RUN:   -enable-experimental-feature CDecl
+// RUN: %FileCheck %s --input-file %t/MiddleLib.h
+// RUN: %check-in-clang-c %t/MiddleLib.h -I %t
+
+/// Build a client.
+// RUN: %clang-no-modules -c %t/Client.c -I %t \
+// RUN:   -F %S/../Inputs/clang-importer-sdk-path/frameworks \
+// RUN:   -I %clang-include-dir -Werror \
+// RUN:   -isysroot %S/../Inputs/clang-importer-sdk
+
+// REQUIRES: swift_feature_CDecl
+
+//--- CoreLib.swift
+@c("CEnum")
+public enum CEnum: CInt { case A, B }
+
+//--- MiddleLib.swift
+import CoreLib
+
+@c("CFunc")
+public func CFunc(e: CEnum) {}
+// CHECK: typedef SWIFT_ENUM_FWD_DECL(int, CEnum)
+// CHECK: SWIFT_EXTERN void CFunc(SWIFT_ENUM_TAG CEnum e) SWIFT_NOEXCEPT;
+
+//--- Client.c
+#include "CoreLib.h"
+#include "MiddleLib.h"
+
+int main() {
+    CFunc(CEnumA);
+}
diff --git a/test/PrintAsObjC/cdecl-enums.swift b/test/PrintAsObjC/cdecl-enums.swift
new file mode 100644
index 0000000000000..0c1cd99a339f8
--- /dev/null
+++ b/test/PrintAsObjC/cdecl-enums.swift
@@ -0,0 +1,126 @@
+/// Variant of PrintAsObjC/enums.swift for @c enums.
+
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-source-import \
+// RUN:   -emit-module -emit-module-doc -o %t %s \
+// RUN:   -import-objc-header %S/Inputs/enums.h \
+// RUN:   -emit-objc-header-path %t/enums.h \
+// RUN:   -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CDecl
+
+// RUN: %FileCheck %s --input-file %t/enums.h
+// RUN: %FileCheck -check-prefix=NEGATIVE %s --input-file %t/enums.h
+// RUN: %check-in-clang %t/enums.h
+
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: objc_interop
+
+import Foundation
+
+// NEGATIVE-NOT: enum EnumNamed
+
+/// No error domains in C mode.
+// NEGATIVE-NOT: @"main.
+
+// CHECK-LABEL: typedef SWIFT_ENUM_NAMED(ptrdiff_t, ObjcEnumNamed, "EnumNamed", closed) {
+// CHECK-NEXT:   ObjcEnumNamedA = 0,
+// CHECK-NEXT:   ObjcEnumNamedB = 1,
+// CHECK-NEXT:   ObjcEnumNamedC = 2,
+// CHECK-NEXT:   ObjcEnumNamedD = 3,
+// CHECK-NEXT:   ObjcEnumNamedHelloDolly = 4,
+// CHECK-NEXT: };
+
+@c(ObjcEnumNamed) enum EnumNamed: Int {
+  case A, B, C, d, helloDolly
+}
+
+// CHECK-LABEL: typedef SWIFT_ENUM(unsigned int, ExplicitValues, closed) {
+// CHECK-NEXT:   ExplicitValuesZim = 0,
+// CHECK-NEXT:   ExplicitValuesZang = 219,
+// CHECK-NEXT:   ExplicitValuesZung = 220,
+// CHECK-NEXT: };
+// NEGATIVE-NOT: ExplicitValuesDomain
+
+@c enum ExplicitValues: CUnsignedInt {
+  case Zim, Zang = 219, Zung
+
+  func methodNotExportedToC() {}
+}
+
+// CHECK: /// Foo: A feer, a female feer.
+// CHECK-NEXT: typedef SWIFT_ENUM_NAMED(int, FooComments, "FooComments", closed) {
+// CHECK: /// Zim: A zeer, a female zeer.
+// CHECK-NEXT:   FooCommentsZim = 0,
+// CHECK-NEXT:   FooCommentsZang = 1,
+// CHECK-NEXT:   FooCommentsZung = 2,
+// CHECK-NEXT: }
+
+/// Foo: A feer, a female feer.
+@c("FooComments") public enum FooComments: CInt {
+  /// Zim: A zeer, a female zeer.
+  case Zim
+  case Zang, Zung
+}
+
+// CHECK-LABEL: typedef SWIFT_ENUM_NAMED(int16_t, NegativeValues, "NegativeValues", closed) {
+// CHECK-NEXT:   Zang = -219,
+// CHECK-NEXT:   Zung = -218,
+// CHECK-NEXT: };
+@c("NegativeValues") enum NegativeValues: Int16 {
+  case Zang = -219, Zung
+
+  func methodNotExportedToC() {}
+}
+
+// CHECK-LABEL: typedef SWIFT_ENUM_NAMED(ptrdiff_t, SomeError, "SomeError", closed) {
+// CHECK-NEXT:   SomeErrorBadness = 9001,
+// CHECK-NEXT:   SomeErrorWorseness = 9002,
+// CHECK-NEXT: };
+@c("SomeError") enum SomeError: Int, Error {
+  case Badness = 9001
+  case Worseness
+}
+
+// CHECK-LABEL: typedef SWIFT_ENUM_NAMED(ptrdiff_t, SomeOtherError, "SomeOtherError", closed) {
+// CHECK-NEXT:   SomeOtherErrorDomain = 0,
+// CHECK-NEXT: };
+@c("SomeOtherError") enum SomeOtherError: Int, Error {
+  case Domain
+}
+
+// CHECK-LABEL: typedef SWIFT_ENUM_NAMED(ptrdiff_t, ObjcErrorType, "SomeRenamedErrorType", closed) {
+// CHECK-NEXT:   ObjcErrorTypeBadStuff = 0,
+// CHECK-NEXT: };
+@c("ObjcErrorType") enum SomeRenamedErrorType: Int, Error {
+  case BadStuff
+}
+
+@c("acceptMemberImported") func acceptMemberImported(a: Wrapper.Raw, b: Wrapper.Enum, c: Wrapper.Options, d: Wrapper.Typedef, e: Wrapper.Anon, ee: Wrapper.Anon2) {}
+// CHECK-LABEL: SWIFT_EXTERN void acceptMemberImported(enum MemberRaw a, enum MemberEnum b, MemberOptions c, enum MemberTypedef d, MemberAnon e, MemberAnon2 ee) SWIFT_NOEXCEPT;
+
+@c("acceptPlainEnum") func acceptPlainEnum(_: NSMalformedEnumMissingTypedef) {}
+// CHECK-LABEL: SWIFT_EXTERN void acceptPlainEnum(enum NSMalformedEnumMissingTypedef) SWIFT_NOEXCEPT;
+
+@c("acceptTopLevelImported") func acceptTopLevelImported(a: TopLevelRaw, b: TopLevelEnum, c: TopLevelOptions, d: TopLevelTypedef, e: TopLevelAnon) {}
+// CHECK-LABEL: SWIFT_EXTERN void acceptTopLevelImported(enum TopLevelRaw a, TopLevelEnum b, TopLevelOptions c, TopLevelTypedef d, TopLevelAnon e) SWIFT_NOEXCEPT;
+
+@c("takeAndReturnEnumC") func takeAndReturnEnumC(_ foo: FooComments) -> NegativeValues {
+  return .Zung
+}
+// CHECK-LABEL: SWIFT_EXTERN SWIFT_ENUM_TAG NegativeValues takeAndReturnEnumC(SWIFT_ENUM_TAG FooComments foo) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+@c("takeAndReturnRenamedEnum") func takeAndReturnRenamedEnum(_ foo: EnumNamed) -> EnumNamed {
+  return .A
+}
+// CHECK-LABEL: SWIFT_EXTERN SWIFT_ENUM_TAG ObjcEnumNamed takeAndReturnRenamedEnum(SWIFT_ENUM_TAG ObjcEnumNamed foo) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+/// Objective-C user.
+
+// CHECK-LABEL: SWIFT_ENUM_FWD_DECL(int, FooComments)
+// CHECK-LABEL: SWIFT_ENUM_FWD_DECL(int16_t, NegativeValues)
+
+// CHECK-LABEL: SWIFT_EXTERN SWIFT_ENUM_TAG NegativeValues takeAndReturnEnumObjC(SWIFT_ENUM_TAG FooComments foo) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+@_cdecl("takeAndReturnEnumObjC") func takeAndReturnEnumObjC(_ foo: FooComments) -> NegativeValues {
+  return .Zung
+}
diff --git a/test/PrintAsObjC/cdecl-imports.swift b/test/PrintAsObjC/cdecl-imports.swift
index 41540286ccc23..7b153be5e6883 100644
--- a/test/PrintAsObjC/cdecl-imports.swift
+++ b/test/PrintAsObjC/cdecl-imports.swift
@@ -2,6 +2,7 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -parse-as-library -typecheck -verify -emit-objc-header-path %t/swift.h
 // RUN: %FileCheck %s < %t/swift.h
 // RUN: %check-in-clang %t/swift.h
+// RUN: %check-in-clang-c %t/swift.h
 // RUN: %check-in-clang-cxx %t/swift.h
 
 // REQUIRES: objc_interop
diff --git a/test/PrintAsObjC/cdecl-includes-with-objc.swift b/test/PrintAsObjC/cdecl-includes-with-objc.swift
new file mode 100644
index 0000000000000..685d680d30cee
--- /dev/null
+++ b/test/PrintAsObjC/cdecl-includes-with-objc.swift
@@ -0,0 +1,82 @@
+/// Include module for use from both C and Objective-C @c variants.
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t --leading-lines
+
+/// Generate the compatibility header cdecl.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %t/Lib.swift \
+// RUN:   -emit-module -o %t -verify -F %t \
+// RUN:   -emit-clang-header-path %t/cdecl.h \
+// RUN:   -enable-experimental-feature CDecl
+
+/// Check compatibility header directly
+// RUN: %FileCheck %s --input-file %t/cdecl.h
+// RUN: %check-in-clang %t/cdecl.h -F %t
+// RUN: %check-in-clang-c %t/cdecl.h -F %t
+// RUN: %check-in-clang-cxx %t/cdecl.h -F %t
+
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: objc_interop
+
+//--- CFramework.framework/Modules/module.modulemap
+
+framework module CFramework {
+    umbrella header "CFramework.h"
+}
+
+//--- CFramework.framework/Headers/CFramework.h
+
+typedef int IntFromCFramework;
+
+//--- Lib.swift
+
+import CFramework
+import CoreGraphics
+import Foundation
+
+// CHECK-NOT: Foundation;
+
+/// Imports for C variant to @_cdecl
+
+// CHECK: #if __has_feature(objc_modules)
+// CHECK: @import CFramework;
+// CHECK-NEXT: @import CoreGraphics;
+// CHECK-NEXT: #elif defined(__OBJC__)
+// CHECK-NEXT: #import <CFramework{{[/\\]}}CFramework.h>
+// CHECK-NEXT: #import <CoreGraphics.h>
+// CHECK-NEXT: #else
+// CHECK-NEXT: #include <CFramework{{[/\\]}}CFramework.h>
+// CHECK-NEXT: #include <CoreGraphics.h>
+// CHECK-NEXT: #endif
+
+// CHECK: #if defined(__cplusplus)
+// CHECK: extern "C" {
+// CHECK: #endif
+
+@c("get_int_alias")
+public func getIntAlias() -> IntFromCFramework { 42 }
+// CHECK: SWIFT_EXTERN IntFromCFramework get_int_alias(void) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+@c("imports_cgpoint")
+public func importsCGPoint(pt: CGPoint) {  }
+// CHECK: SWIFT_EXTERN void imports_cgpoint(CGPoint pt) SWIFT_NOEXCEPT;
+
+// CHECK: #if defined(__cplusplus)
+// CHECK: } // extern "C"
+// CHECK: #endif
+
+/// Imports for Objective-C variant to @_cdecl
+
+@_cdecl("imports_cgpoint_objc")
+public func importsCGPointObjC(pt: CGPoint) {  }
+// CHECK: #if defined(__OBJC__)
+// CHECK: #if __has_feature(objc_modules)
+// CHECK-NEXT: #if __has_warning("-Watimport-in-framework-header")
+// CHECK-NEXT: #pragma clang diagnostic ignored "-Watimport-in-framework-header"
+// CHECK-NEXT: #endif
+// CHECK-NEXT: @import CoreGraphics;
+// CHECK-NEXT: #endif
+
+// CHECK: #if defined(__OBJC__)
+// CHECK: SWIFT_EXTERN void imports_cgpoint_objc(CGPoint pt) SWIFT_NOEXCEPT;
+// CHECK: #endif
diff --git a/test/PrintAsObjC/cdecl-includes.swift b/test/PrintAsObjC/cdecl-includes.swift
new file mode 100644
index 0000000000000..f9b3e0400337a
--- /dev/null
+++ b/test/PrintAsObjC/cdecl-includes.swift
@@ -0,0 +1,110 @@
+/// Print #includes for C clients and reference imported types.
+/// This test shouldn't require the objc runtime.
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t --leading-lines
+
+/// Generate the compatibility header cdecl.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %t/Lib.swift \
+// RUN:   -emit-module -verify -o %t -I %t \
+// RUN:   -import-bridging-header %t/BridgingHeader.h \
+// RUN:   -emit-clang-header-path %t/cdecl.h \
+// RUN:   -disable-objc-interop \
+// RUN:   -enable-experimental-feature CDecl
+
+/// Check compatibility header directly
+// RUN: %FileCheck %s --input-file %t/cdecl.h
+// RUN: %check-in-clang-c -I %t %t/cdecl.h \
+// RUN:   -isysroot %S/../Inputs/clang-importer-sdk
+
+/// Compile a client against the compatibility header
+// RUN: %clang-no-modules -c %t/Client.c -I %t -Werror \
+// RUN:   -isysroot %S/../Inputs/clang-importer-sdk
+
+// REQUIRES: swift_feature_CDecl
+
+//--- module.modulemap
+
+module CModule {
+    header "CModule_FileA.h"
+    header "sub/CModule_FileB.h"
+}
+
+//--- CModule_FileA.h
+
+struct CStruct { int a; };
+
+//--- sub/CModule_FileB.h
+
+union CUnion { long a; float b; };
+
+//--- Dependency.h
+
+typedef enum TKTimeSetting {
+    TKTimeSettingLight,
+    TKTimeSettingNormal,
+    TKTimeSettingDark
+} TKTimeSetting;
+
+//--- BridgingHeader.h
+
+#include "Dependency.h"
+
+//--- Lib.swift
+
+import CModule
+
+// CHECK: #if __has_feature(objc_modules)
+// CHECK: @import CModule;
+// CHECK-NEXT: #elif defined(__OBJC__)
+// CHECK-NEXT: #import <CModule_FileA.h>
+// CHECK-NEXT: #import <sub{{[/\\]}}CModule_FileB.h>
+// CHECK-NEXT: #else
+// CHECK-NEXT: #include <CModule_FileA.h>
+// CHECK-NEXT: #include <sub{{[/\\]}}CModule_FileB.h>
+// CHECK-NEXT: #endif
+
+// CHECK: #if defined(__OBJC__)
+// CHECK: #import "
+// CHECK-SAME: BridgingHeader.h"
+// CHECK-NEXT: #else
+// CHECK-NEXT: #include "
+// CHECK-SAME: BridgingHeader.h"
+// CHECK-NEXT: #endif
+
+// CHECK-NOT: BridgingHeader
+
+// CHECK: #if defined(__cplusplus)
+// CHECK: extern "C" {
+// CHECK: #endif
+
+@c("mirror_struct")
+public func a_mirrorStruct(_ a: CStruct) -> CStruct { a }
+// CHECK: SWIFT_EXTERN struct CStruct mirror_struct(struct CStruct a) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+@c("mirror_union")
+public func b_mirrorStruct(_ a: CUnion) -> CUnion { a }
+// CHECK: SWIFT_EXTERN union CUnion mirror_union(union CUnion a) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+
+@c("TKGetDefaultToastSetting")
+public func c_defaultToastSetting() -> TKTimeSetting { TKTimeSettingNormal } // It would be nice to import TKTimeSettingNormal as a member.
+// CHECK: SWIFT_EXTERN TKTimeSetting TKGetDefaultToastSetting(void) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+// CHECK:      #if defined(__cplusplus)
+// CHECK-NEXT: }
+// CHECK-NEXT: #endif
+
+//--- Client.c
+
+#include "cdecl.h"
+
+int main() {
+  struct CStruct s = { 42 };
+  struct CStruct s_out = mirror_struct(s);
+
+  union CUnion u = { 43 };
+  union CUnion u_out = mirror_union(u);
+
+  TKTimeSetting def = TKGetDefaultToastSetting();
+}
diff --git a/test/PrintAsObjC/cdecl-official-for-objc-clients.swift b/test/PrintAsObjC/cdecl-official-for-objc-clients.swift
new file mode 100644
index 0000000000000..94be91e72f2c0
--- /dev/null
+++ b/test/PrintAsObjC/cdecl-official-for-objc-clients.swift
@@ -0,0 +1,23 @@
+/// Similar test to cdecl-official but gated to objc-interop compatibility
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %S/cdecl-official.swift %t --leading-lines
+
+/// Generate cdecl.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   %t/Lib.swift -emit-module -verify -o %t -emit-module-doc \
+// RUN:   -emit-clang-header-path %t/cdecl.h \
+// RUN:   -enable-experimental-feature CDecl
+
+/// Check cdecl.h directly
+// RUN: %check-in-clang %t/cdecl.h
+// RUN: %check-in-clang-cxx %t/cdecl.h
+
+/// Build an Objective-C client against cdecl.h
+// RUN: %clang -c %t/Client.c -fmodules -I %t \
+// RUN:   -F %S/../Inputs/clang-importer-sdk-path/frameworks \
+// RUN:   -I %clang-include-dir -Werror \
+// RUN:   -isysroot %S/../Inputs/clang-importer-sdk
+
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: objc_interop
diff --git a/test/PrintAsObjC/cdecl-official-visibility.swift b/test/PrintAsObjC/cdecl-official-visibility.swift
new file mode 100644
index 0000000000000..2ba59eb722e1a
--- /dev/null
+++ b/test/PrintAsObjC/cdecl-official-visibility.swift
@@ -0,0 +1,64 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t --leading-lines
+
+/// Generate cdecl.h for an app
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   %t/Lib.swift -emit-module -verify -o %t -emit-module-doc \
+// RUN:   -emit-clang-header-path %t/cdecl.h -package-name pkg \
+// RUN:   -enable-experimental-feature CDecl
+// RUN: %FileCheck %s --input-file %t/cdecl.h --check-prefixes PUBLIC-AND-INTERNAL,INTERNAL-ONLY
+// RUN: %check-in-clang-c %t/cdecl.h
+
+/// Generate cdecl.h for a library
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -parse-as-library \
+// RUN:   %t/Lib.swift -emit-module -verify -o %t -emit-module-doc \
+// RUN:   -emit-clang-header-path %t/cdecl.h -package-name pkg \
+// RUN:   -enable-experimental-feature CDecl
+// RUN: %FileCheck %s --input-file %t/cdecl.h --check-prefixes PUBLIC-AND-INTERNAL
+// RUN: %FileCheck %s --input-file %t/cdecl.h --implicit-check-not INTERNAL-ONLY
+// RUN: %check-in-clang-c %t/cdecl.h
+
+// REQUIRES: swift_feature_CDecl
+
+//--- Lib.swift
+
+@c private enum PrivateEnum: CInt { case A, B }
+// PUBLIC-AND-INTERNAL-NOT: PrivateEnum
+
+@c internal enum InternalEnum: CInt { case A, B }
+// INTERNAL-ONLY: typedef SWIFT_ENUM(int, InternalEnum, closed) {
+// INTERNAL-ONLY:   InternalEnumA = 0,
+// INTERNAL-ONLY:   InternalEnumB = 1,
+// INTERNAL-ONLY: };
+
+@c package enum PackageEnum: CInt { case A, B }
+// INTERNAL-ONLY: typedef SWIFT_ENUM(int, PackageEnum, closed) {
+// INTERNAL-ONLY:   PackageEnumA = 0,
+// INTERNAL-ONLY:   PackageEnumB = 1,
+// INTERNAL-ONLY: };
+
+@c public enum PublicEnum: CInt { case A, B }
+// PUBLIC-AND-INTERNAL: typedef SWIFT_ENUM(int, PublicEnum, closed) {
+// PUBLIC-AND-INTERNAL:   PublicEnumA = 0,
+// PUBLIC-AND-INTERNAL:   PublicEnumB = 1,
+// PUBLIC-AND-INTERNAL: };
+
+/// Private documentation
+@c private func a_private() {}
+// PUBLIC-AND-INTERNAL-NOT: // Private documentation
+// PUBLIC-AND-INTERNAL-NOT: a_private
+
+/// Internal documentation
+@c internal func b_internal() {}
+// INTERNAL-ONLY: // Internal documentation
+// INTERNAL-ONLY: b_internal
+
+/// Package documentation
+@c package func c_package() {}
+// INTERNAL-ONLY: // Package documentation
+// INTERNAL-ONLY: c_package
+
+/// Public documentation
+@c public func d_public() {}
+// PUBLIC-AND-INTERNAL: // Public documentation
+// PUBLIC-AND-INTERNAL: d_public
diff --git a/test/PrintAsObjC/cdecl-official.swift b/test/PrintAsObjC/cdecl-official.swift
new file mode 100644
index 0000000000000..b7bc81f6ba64e
--- /dev/null
+++ b/test/PrintAsObjC/cdecl-official.swift
@@ -0,0 +1,127 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t --leading-lines
+
+/// Generate cdecl.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   %t/Lib.swift -emit-module -verify -o %t -emit-module-doc \
+// RUN:   -emit-clang-header-path %t/cdecl.h \
+// RUN:   -enable-experimental-feature CDecl
+
+/// Check cdecl.h directly
+// RUN: %FileCheck %s --input-file %t/cdecl.h
+// RUN: %check-in-clang-c %t/cdecl.h -Wnullable-to-nonnull-conversion
+
+/// Build a client against cdecl.h
+// RUN: %clang-no-modules -c %t/Client.c -I %t \
+// RUN:   -F %S/../Inputs/clang-importer-sdk-path/frameworks \
+// RUN:   -I %clang-include-dir -Werror \
+// RUN:   -isysroot %S/../Inputs/clang-importer-sdk
+
+// REQUIRES: swift_feature_CDecl
+
+//--- Lib.swift
+
+// CHECK-NOT: assume_nonnull
+
+// CHECK: #if defined(__cplusplus)
+// CHECK: extern "C" {
+// CHECK: #endif
+
+// CHECK: /// Enums
+// CHECK: typedef SWIFT_ENUM(int, CEnum, closed) {
+// CHECK:   CEnumA = 0,
+// CHECK:   CEnumB = 1,
+// CHECK: };
+
+// CHECK: typedef SWIFT_ENUM_NAMED(long, CEnumRenamed_CName, "CEnumRenamed", closed) {
+// CHECK:   CEnumRenamed_CNameA = 0,
+// CHECK:   CEnumRenamed_CNameB = 1,
+// CHECK: };
+
+// CHECK: typedef SWIFT_ENUM_NAMED(char, zCEnumDefinedLate, "zCEnumDefinedLate", closed) {
+// CHECK:   CEnumDefinedLateA = 0,
+// CHECK:   CEnumDefinedLateB = 1,
+// CHECK: };
+
+/// My documentation
+@c(simple)
+func a0_simple(x: Int, bar y: Int) -> Int { return x }
+// CHECK-LABEL: // My documentation
+// CHECK-LABEL: SWIFT_EXTERN ptrdiff_t simple(ptrdiff_t x, ptrdiff_t y) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+@c
+func a1_defaultName(x: Int) -> Int { return x }
+// CHECK-LABEL: SWIFT_EXTERN ptrdiff_t a1_defaultName(ptrdiff_t x) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+@c("primitiveTypes")
+public func b_primitiveTypes(i: Int, ci: CInt, l: CLong, c: CChar, f: Float, d: Double, b: Bool) {}
+// CHECK-LABEL: SWIFT_EXTERN void primitiveTypes(ptrdiff_t i, int ci, long l, char c, float f, double d, bool b) SWIFT_NOEXCEPT;
+
+@c("has_keyword_arg_names")
+func c_keywordArgNames(auto: Int, union: Int) {}
+// CHECK-LABEL: SWIFT_EXTERN void has_keyword_arg_names(ptrdiff_t auto_, ptrdiff_t union_) SWIFT_NOEXCEPT;
+
+@c("return_never")
+func d_returnNever() -> Never { fatalError() }
+// CHECK-LABEL: SWIFT_EXTERN void return_never(void) SWIFT_NOEXCEPT SWIFT_NORETURN;
+
+/// Pointer types
+// CHECK: /// Pointer types
+
+@c("pointers")
+func f_pointers(_ x: UnsafeMutablePointer<Int>,
+                  y: UnsafePointer<Int>,
+                  z: UnsafeMutableRawPointer,
+                  w: UnsafeRawPointer,
+                  u: OpaquePointer) {}
+// CHECK: SWIFT_EXTERN void pointers(ptrdiff_t * _Nonnull x, ptrdiff_t const * _Nonnull y, void * _Nonnull z, void const * _Nonnull w, void * _Nonnull u) SWIFT_NOEXCEPT;
+
+@c("nullable_pointers")
+func g_nullablePointers(_ x: UnsafeMutableRawPointer,
+                          y: UnsafeMutableRawPointer?,
+                          z: UnsafeMutableRawPointer!) {}
+// CHECK: SWIFT_EXTERN void nullable_pointers(void * _Nonnull x, void * _Nullable y, void * _Null_unspecified z) SWIFT_NOEXCEPT;
+
+/// Enums
+
+@c
+enum CEnum: CInt { case A, B }
+
+@c("CEnumRenamed_CName")
+enum CEnumRenamed: CLong { case A, B }
+
+@c("use_enum")
+func h_useCEnum(e: CEnum) -> CEnum { return e }
+// CHECK: SWIFT_EXTERN SWIFT_ENUM_TAG CEnum use_enum(SWIFT_ENUM_TAG CEnum e) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+@c("use_enum_renamed")
+func i_useCEnumLong(e: CEnumRenamed) -> CEnumRenamed { return e }
+// CHECK: SWIFT_EXTERN SWIFT_ENUM_TAG CEnumRenamed_CName use_enum_renamed(SWIFT_ENUM_TAG CEnumRenamed_CName e) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+@c("use_enum_late")
+func j_useCEnumChar(e: zCEnumDefinedLate) -> zCEnumDefinedLate { return e }
+// CHECK: SWIFT_EXTERN SWIFT_ENUM_TAG zCEnumDefinedLate use_enum_late(SWIFT_ENUM_TAG zCEnumDefinedLate e) SWIFT_NOEXCEPT SWIFT_WARN_UNUSED_RESULT;
+
+/// Declare this enum late in the source file and in alphabetical order.
+@c("zCEnumDefinedLate")
+enum zCEnumDefinedLate: CChar { case A, B }
+
+// CHECK:      #if defined(__cplusplus)
+// CHECK-NEXT: }
+// CHECK-NEXT: #endif
+
+//--- Client.c
+
+#include "cdecl.h"
+
+int main() {
+    ptrdiff_t x = simple(42, 43);
+    primitiveTypes(1, 2, 3, 'a', 1.0f, 2.0, true);
+    has_keyword_arg_names(1, 2);
+
+    (void)use_enum(CEnumA);
+    (void)use_enum_renamed(CEnumRenamed_CNameB);
+    (void)use_enum_late(zCEnumDefinedLateA);
+
+    return_never();
+}
diff --git a/test/PrintAsObjC/cdecl-with-objc.swift b/test/PrintAsObjC/cdecl-with-objc.swift
new file mode 100644
index 0000000000000..4048dcdbe852a
--- /dev/null
+++ b/test/PrintAsObjC/cdecl-with-objc.swift
@@ -0,0 +1,33 @@
+/// Ensure we print @c and @_cdecl only once.
+
+// RUN: %empty-directory(%t)
+
+/// Generate cdecl.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   %s -emit-module -verify -o %t -emit-module-doc \
+// RUN:   -emit-objc-header-path %t/cdecl.h \
+// RUN:   -disable-objc-attr-requires-foundation-module \
+// RUN:   -enable-experimental-feature CDecl
+
+/// Check cdecl.h directly
+// RUN: %FileCheck %s --input-file %t/cdecl.h
+// RUN: %check-in-clang %t/cdecl.h
+// RUN: %check-in-clang-c %t/cdecl.h -Wnullable-to-nonnull-conversion
+// RUN: %check-in-clang-cxx %t/cdecl.h
+
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: objc_interop
+
+@c("cFunc")
+func cFunc() { }
+// CHECK: cFunc
+// CHECK-NOT: cFunc
+
+/// The class would break C parsing if printed in wrong block
+@objc
+class ObjCClass {}
+
+@_cdecl("objcFunc")
+func objcFunc() -> ObjCClass! { return ObjCClass() }
+// CHECK: objcFunc
+// CHECK-NOT: objcFunc
diff --git a/test/PrintAsObjC/cdecl.swift b/test/PrintAsObjC/cdecl.swift
index 307159d956171..780121bb97d68 100644
--- a/test/PrintAsObjC/cdecl.swift
+++ b/test/PrintAsObjC/cdecl.swift
@@ -4,6 +4,7 @@
 // RUN: %FileCheck %s < %t/cdecl.h
 // RUN: %check-in-clang %t/cdecl.h
 // RUN: %check-in-clang -fno-modules -Qunused-arguments %t/cdecl.h -include ctypes.h -include CoreFoundation.h
+// RUN: %check-in-clang-c -fno-modules -Qunused-arguments %t/cdecl.h -include ctypes.h -include CoreFoundation.h
 // RUN: %check-in-clang-cxx -fno-modules -Qunused-arguments %t/cdecl.h -include ctypes.h -include CoreFoundation.h
 
 // REQUIRES: objc_interop
diff --git a/test/PrintAsObjC/emit-clang-header-nonmodular-includes-mock-sdk.swift b/test/PrintAsObjC/emit-clang-header-nonmodular-includes-mock-sdk.swift
index fa2fe7cef598a..d053c463c5488 100644
--- a/test/PrintAsObjC/emit-clang-header-nonmodular-includes-mock-sdk.swift
+++ b/test/PrintAsObjC/emit-clang-header-nonmodular-includes-mock-sdk.swift
@@ -4,6 +4,7 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -F %S/Inputs/ -typecheck -verify -emit-objc-header-path %t/textual-imports.h -emit-clang-header-nonmodular-includes %s 
 // RUN: %FileCheck %s < %t/textual-imports.h
 // RUN: %check-in-clang -fno-modules -Qunused-arguments %t/textual-imports.h -F %S/Inputs
+// RUN: %check-in-clang-c %t/textual-imports.h -F %S/Inputs
 
 import Foundation
 import Mixed
@@ -30,9 +31,14 @@ public class HelloWorld: NSObject {
 // CHECK-NEXT: @import CoreGraphics;
 // CHECK-NEXT: @import Mixed;
 // CHECK-NEXT: @import ObjectiveC;
-// CHECK-NEXT: #else
+// CHECK-NEXT: #elif defined(__OBJC__)
 // CHECK-NEXT: #import <CoreGraphics.h>
 // CHECK-NEXT: #import <Mixed/Mixed.h>
 // CHECK-NEXT: #import <objc/objc.h>
 // CHECK-NEXT: #import <objc/NSObject.h>
+// CHECK-NEXT: #else
+// CHECK-NEXT: #include <CoreGraphics.h>
+// CHECK-NEXT: #include <Mixed/Mixed.h>
+// CHECK-NEXT: #include <objc/objc.h>
+// CHECK-NEXT: #include <objc/NSObject.h>
 // CHECK-NEXT: #endif
diff --git a/test/PrintAsObjC/emit-clang-header-nonmodular-includes-modulemap-not-in-include-dir.swift b/test/PrintAsObjC/emit-clang-header-nonmodular-includes-modulemap-not-in-include-dir.swift
index 5c073aba1e779..d2e5454b787df 100644
--- a/test/PrintAsObjC/emit-clang-header-nonmodular-includes-modulemap-not-in-include-dir.swift
+++ b/test/PrintAsObjC/emit-clang-header-nonmodular-includes-modulemap-not-in-include-dir.swift
@@ -16,6 +16,8 @@ public class Bar : Baz {}
 // CHECK-NEXT: #pragma clang diagnostic ignored "-Watimport-in-framework-header"
 // CHECK-NEXT: #endif
 // CHECK-NEXT: @import EmitClangHeaderNonmodularIncludesStressTest;
-// CHECK-NEXT: #else
-// CHECK: #import <header-regular.h>
+// CHECK-NEXT: #elif defined(__OBJC__)
+// CHECK-NEXT: #import <header-regular.h>
+// CHECK: #else
+// CHECK-NEXT: #include <header-regular.h>
 // CHECK: #endif
diff --git a/test/PrintAsObjC/emit-clang-header-nonmodular-includes-path-normalization.swift b/test/PrintAsObjC/emit-clang-header-nonmodular-includes-path-normalization.swift
index abd61424ed432..3e4ca18b47648 100644
--- a/test/PrintAsObjC/emit-clang-header-nonmodular-includes-path-normalization.swift
+++ b/test/PrintAsObjC/emit-clang-header-nonmodular-includes-path-normalization.swift
@@ -14,6 +14,8 @@ public class Bar : Baz {}
 // CHECK-NEXT: #pragma clang diagnostic ignored "-Watimport-in-framework-header"
 // CHECK-NEXT: #endif
 // CHECK-NEXT: @import EmitClangHeaderNonmodularIncludesStressTest;
-// CHECK-NEXT: #else
-// CHECK: #import <header-regular.h>
+// CHECK-NEXT: #elif defined(__OBJC__)
+// CHECK-NEXT: #import <header-regular.h>
+// CHECK: #else
+// CHECK-NEXT: #include <header-regular.h>
 // CHECK: #endif
diff --git a/test/PrintAsObjC/emit-clang-header-nonmodular-includes-symlinked-header.swift b/test/PrintAsObjC/emit-clang-header-nonmodular-includes-symlinked-header.swift
index 9e4547a83c430..4ac059c77112c 100644
--- a/test/PrintAsObjC/emit-clang-header-nonmodular-includes-symlinked-header.swift
+++ b/test/PrintAsObjC/emit-clang-header-nonmodular-includes-symlinked-header.swift
@@ -16,6 +16,8 @@ public class Bar : Foo {}
 // CHECK-NEXT: #pragma clang diagnostic ignored "-Watimport-in-framework-header"
 // CHECK-NEXT: #endif
 // CHECK-NEXT: @import EmitClangHeaderNonmodularIncludesStressTest;
-// CHECK-NEXT: #else
+// CHECK-NEXT: #elif defined(__OBJC__)
 // CHECK: #import <header-symlink.h>
+// CHECK-NEXT: #else
+// CHECK: #include <header-symlink.h>
 // CHECK: #endif
diff --git a/test/PrintAsObjC/lit.local.cfg b/test/PrintAsObjC/lit.local.cfg
index a517a4a80ca14..a6c2d56b3f06c 100644
--- a/test/PrintAsObjC/lit.local.cfg
+++ b/test/PrintAsObjC/lit.local.cfg
@@ -10,6 +10,14 @@ config.substitutions.insert(0, ('%check-in-clang',
   '-I %%clang-include-dir '
   '-isysroot %r/Inputs/clang-importer-sdk' % config.test_source_root) )
 
+config.substitutions.insert(0, ('%check-in-clang-c',
+  '%%clang-no-modules -fsyntax-only -x c-header -std=c99 '
+  '-Weverything -Werror -Wno-unused-macros -Wno-incomplete-module '
+  '-Wno-auto-import -Wno-poison-system-directories -Wno-c++-keyword '
+  '-Wno-unknown-warning-option -F %%clang-importer-sdk-path/frameworks '
+  '-I %%clang-include-dir '
+  '-isysroot %r/Inputs/clang-importer-sdk' % config.test_source_root) )
+
 config.substitutions.insert(0, ('%check-in-clang-cxx',
   '%%clang -fsyntax-only -x objective-c++-header -std=c++17 '
   '-fobjc-arc -fmodules -fmodules-validate-system-headers '
diff --git a/test/PrintAsObjC/unicode-scalar-reference.swift b/test/PrintAsObjC/unicode-scalar-reference.swift
new file mode 100644
index 0000000000000..19adf494d45c1
--- /dev/null
+++ b/test/PrintAsObjC/unicode-scalar-reference.swift
@@ -0,0 +1,32 @@
+// RUN: %empty-directory(%t)
+
+// Test the behavior of printing Unicode.Scalar in the compatibility header.
+// This is wrong, it should either be rejected and considered non-representable
+// or actually be printed using a C / Objective-C compatible type.
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   %s -emit-module -verify -o %t -emit-module-doc \
+// RUN:   -emit-clang-header-path %t/compat.h
+// RUN: %FileCheck %s --input-file %t/compat.h
+
+@_cdecl("referencesScalar")
+func referencesScalar() -> Unicode.Scalar { fatalError() }
+// CHECK: SWIFT_EXTERN char32_t referencesScalar(void)
+
+@_cdecl("referencesRelated")
+func x_referencesRelated(a: CChar32, b: CWideChar) { }
+// CHECK: SWIFT_EXTERN void referencesRelated(char32_t a, wchar_t b)
+
+#if !((os(macOS) || targetEnvironment(macCatalyst)) && arch(x86_64))
+    // Actual test of Float16, on supported platforms.
+    @available(watchOS 7.0, *)
+    @_cdecl("referencesFloat16")
+    func y_referencesFloat16(a: Float16, b: CFloat16) { }
+#else
+    // Just print the expected string on macOS&x86_64 where there's no Float16.
+    // This disables this one check on unsupported platforms.
+    /// SWIFT_EXTERN void referencesFloat16(_Float16 a, _Float16 b)
+    @_cdecl("printTheDoc")
+    public func y_printTheDoc() { }
+#endif
+// CHECK: SWIFT_EXTERN void referencesFloat16(_Float16 a, _Float16 b)
diff --git a/test/Profiler/coverage_inlined_counters.swift b/test/Profiler/coverage_inlined_counters.swift
index 0dcf4944ed3d6..e1a56ed1e53ba 100644
--- a/test/Profiler/coverage_inlined_counters.swift
+++ b/test/Profiler/coverage_inlined_counters.swift
@@ -17,6 +17,7 @@
 // RUN: env SWIFT_USE_OLD_DRIVER=1 %target-build-swift %t/b.swift -profile-generate -profile-coverage-mapping -o %t/main -module-name B -I %t/out %t/out/a.swift.o
 
 // REQUIRES: profile_runtime
+// UNSUPPORTED: OS=ios && CPU=arm64e
 
 //--- a.swift
 @_transparent
diff --git a/test/Profiler/unmapped.swift b/test/Profiler/unmapped.swift
index 8ea472b527bfc..b4db4bbab3d9c 100644
--- a/test/Profiler/unmapped.swift
+++ b/test/Profiler/unmapped.swift
@@ -47,6 +47,11 @@ struct TypeWithUnavailableMethods {
   func foo() -> Int {
     .random() ? 1 : 2
   }
+
+  @available(*, unavailable)
+  var qux: Int {
+    .random() ? 1 : 2
+  }
 }
 
 @available(*, unavailable)
diff --git a/test/Prototypes/CollectionTransformers.swift b/test/Prototypes/CollectionTransformers.swift
index 4943ba01d0c57..e8d04cfc7b28a 100644
--- a/test/Prototypes/CollectionTransformers.swift
+++ b/test/Prototypes/CollectionTransformers.swift
@@ -200,7 +200,7 @@ import Darwin
 import Dispatch
 
 // FIXME: port to Linux.
-// XFAIL: OS=linux-gnu, OS=windows-msvc, OS=openbsd, OS=linux-android
+// XFAIL: OS=linux-gnu, OS=windows-msvc, OS=freebsd, OS=openbsd, OS=linux-android
 
 // A wrapper for pthread_t with platform-independent interface.
 public struct _stdlib_pthread_t : Equatable, Hashable {
diff --git a/test/Prototypes/Hypoarray.swift b/test/Prototypes/Hypoarray.swift
index 909ce3dacec40..d0dd8beb14f28 100644
--- a/test/Prototypes/Hypoarray.swift
+++ b/test/Prototypes/Hypoarray.swift
@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift -swift-version 6 -o %t/a.out %s
+// RUN: %target-build-swift -o %t/a.out %s
 // RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out
 // REQUIRES: executable_test
diff --git a/test/Prototypes/builtin-vector-via-extern-c.swift b/test/Prototypes/builtin-vector-via-extern-c.swift
new file mode 100644
index 0000000000000..5f1d8e4004d9e
--- /dev/null
+++ b/test/Prototypes/builtin-vector-via-extern-c.swift
@@ -0,0 +1,29 @@
+//===----------------------------------------------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+// REQUIRES: swift_feature_Extern
+// REQUIRES: swift_feature_BuiltinModule
+// RUN: %target-swift-frontend -primary-file %s -enable-experimental-feature BuiltinModule -enable-experimental-feature Extern -emit-ir | %FileCheck %s --check-prefix=CHECK
+
+import Builtin
+
+@_extern(c, "llvm.uadd.sat.v16i8") @usableFromInline
+func _uaddSat(_ a: Builtin.Vec16xInt8, _ b: Builtin.Vec16xInt8) -> Builtin.Vec16xInt8
+
+@_transparent
+public func saturatingAdd(_ a: SIMD16<UInt8>, _ b: SIMD16<UInt8>) -> SIMD16<UInt8> {
+  // Hack around init from Builtin type being stdlib-internal using unsafeBitCast.
+  unsafeBitCast(_uaddSat(a._storage._value, b._storage._value), to: SIMD16<UInt8>.self)
+}
+// CHECK: saturatingAdd{{.*}} {
+// CHECK: entry:
+// CHECK: call <16 x i8> @llvm.uadd.sat.v16i8
+
diff --git a/test/Reflection/Inputs/Packs.swift b/test/Reflection/Inputs/Packs.swift
new file mode 100644
index 0000000000000..33d9748ba7353
--- /dev/null
+++ b/test/Reflection/Inputs/Packs.swift
@@ -0,0 +1,51 @@
+
+public typealias Second<T, U> = U
+
+public struct Packed<each T, U> {
+  public var tuple1: (repeat each T)
+  public var tuple2: (repeat (each T) -> ())
+  public var tuple3: (repeat Scalar<each T>)
+  public var tuple4: (repeat Second<each T, Int>)
+
+  public var func1: (repeat each T) -> ()
+  public var func2: (repeat Scalar<each T>) -> ()
+  public var func3: (repeat Second<each T, Int>) -> ()
+
+  public var nominal1: AlsoPacked<repeat each T>
+  public var nominal2: AlsoPacked<repeat Scalar<each T>>
+  public var nominal3: AlsoPacked<repeat Second<each T, Int>>
+}
+
+public struct AlsoPacked<each T> {
+  public var t: (repeat each T)
+}
+
+public struct Scalar<T> {
+  public var t: T
+}
+
+public protocol P {
+  associatedtype A
+  var t: A { get }
+}
+
+extension AlsoPacked: P {}
+
+public struct NestedPacked<each T> {
+  public struct Inner<each U> {
+    var t: (repeat Packed<repeat each U, each T>)
+    var u: (repeat AlsoPacked<repeat each U, each T>)
+  }
+}
+
+public struct Simple {
+  var x1: AlsoPacked<Float>
+  var x2: AlsoPacked<Int, Float>
+  var x3: AlsoPacked<Int, String, Float>
+}
+
+public struct Complex {
+  var x1: Packed<Float>
+  var x2: Packed<Int, Float>
+  var x3: Packed<Int, String, Float>
+}
\ No newline at end of file
diff --git a/test/Reflection/Inputs/wasm.yaml b/test/Reflection/Inputs/wasm.yaml
new file mode 100644
index 0000000000000..4a5338b309acf
--- /dev/null
+++ b/test/Reflection/Inputs/wasm.yaml
@@ -0,0 +1,443 @@
+--- !WASM
+FileHeader:
+  Version:         0x1
+Sections:
+  - Type:            TYPE
+    Signatures:
+      - Index:           0
+        ParamTypes:
+          - I32
+          - I32
+        ReturnTypes:
+          - I32
+      - Index:           1
+        ParamTypes:
+          - I32
+        ReturnTypes:     []
+      - Index:           2
+        ParamTypes:      []
+        ReturnTypes:     []
+      - Index:           3
+        ParamTypes:
+          - I32
+          - I32
+        ReturnTypes:     []
+      - Index:           4
+        ParamTypes:
+          - I32
+          - I32
+          - I32
+          - I32
+        ReturnTypes:     []
+      - Index:           5
+        ParamTypes:
+          - I32
+        ReturnTypes:
+          - I32
+      - Index:           6
+        ParamTypes:
+          - I32
+          - I32
+          - I32
+        ReturnTypes:
+          - I32
+      - Index:           7
+        ParamTypes:      []
+        ReturnTypes:
+          - I32
+  - Type:            IMPORT
+    Imports:
+      - Module:          wasi_snapshot_preview1
+        Field:           args_get
+        Kind:            FUNCTION
+        SigIndex:        0
+      - Module:          wasi_snapshot_preview1
+        Field:           args_sizes_get
+        Kind:            FUNCTION
+        SigIndex:        0
+      - Module:          wasi_snapshot_preview1
+        Field:           proc_exit
+        Kind:            FUNCTION
+        SigIndex:        1
+  - Type:            FUNCTION
+    FunctionTypes:   [ 2, 1, 2, 2, 0, 3, 4, 4, 5, 5, 6, 1, 1, 0, 1, 7, 
+                       0, 0, 1, 2, 5, 2, 2, 6 ]
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+    Tables:
+      - Index:           0
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+      - Minimum:         0x2
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+        Mutable:         true
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+        Functions:       [ 9, 10, 7 ]
+  - Type:            CODE
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+        Body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
+  - Type:            DATA
+    Segments:
+      - SectionOffset:   8
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4096
+        Content:         10000000480000008000000000000000430001005C0000006400000000000000010000005A0000000700000000000000510000003C000000480000000100000094000000000000000200000051000000200000002E0000000200000088000000010000000200000073696D706C6500000000000000000000F0FFFFFF50004100540053000300
+      - SectionOffset:   148
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4232
+        Content:         001000001D110000000000000010000000020000301000000000000000100000000200004C10000000000000
+      - SectionOffset:   198
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4276
+        Content:         5CFFFFFF
+      - SectionOffset:   208
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4280
+        Content:         48FFFFFF
+      - SectionOffset:   218
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4284
+        Content:         74FFFFFF8CFFFFFF
+      - SectionOffset:   232
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4292
+        Content:         640000000000000004000C0000000000620000000000000000000C00000000003E0000000000000000000C0001000000000000003E0000001E000000
+      - SectionOffset:   298
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4352
+        Content:         ''
+      - SectionOffset:   304
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4352
+        Content:         '220000002400000001000000080000000800000008000000'
+      - SectionOffset:   334
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4376
+        Content:         ''
+      - SectionOffset:   340
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4376
+        Content:         '41007400'
+      - SectionOffset:   350
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4380
+        Content:         426933325F000129FFFFFF0024733673696D706C65315050000001F9FEFFFF00
+      - SectionOffset:   388
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4412
+        Content:         ''
+      - SectionOffset:   394
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4412
+        Content:         ''
+      - SectionOffset:   400
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4412
+        Content:         ''
+      - SectionOffset:   406
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4412
+        Content:         ''
+      - SectionOffset:   412
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4412
+        Content:         ''
+      - SectionOffset:   418
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4412
+        Content:         ''
+      - SectionOffset:   424
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4412
+        Content:         '0300000000000000'
+      - SectionOffset:   438
+        InitFlags:       0
+        Offset:
+          Opcode:          I32_CONST
+          Value:           4420
+        Content:         F94D3CBDE6014046B3FF38670353FD4E
+  - Type:            CUSTOM
+    Name:            .swift1_autolink_entries
+    Payload:         ''
+  - Type:            CUSTOM
+    Name:            name
+    FunctionNames:
+      - Index:           0
+        Name:            __imported_wasi_snapshot_preview1_args_get
+      - Index:           1
+        Name:            __imported_wasi_snapshot_preview1_args_sizes_get
+      - Index:           2
+        Name:            __imported_wasi_snapshot_preview1_proc_exit
+      - Index:           3
+        Name:            __wasm_call_ctors
+      - Index:           4
+        Name:            'signature_mismatch:swift_addNewDSOImage'
+      - Index:           5
+        Name:            _start
+      - Index:           6
+        Name:            'swift_image_constructor()'
+      - Index:           7
+        Name:            main
+      - Index:           8
+        Name:            '$s6simple1SV1tAA1TVvg'
+      - Index:           9
+        Name:            '$s6simple1TVMa'
+      - Index:           10
+        Name:            '$s6simple1SVMa'
+      - Index:           11
+        Name:            malloc
+      - Index:           12
+        Name:            dlmalloc
+      - Index:           13
+        Name:            prepend_alloc
+      - Index:           14
+        Name:            free
+      - Index:           15
+        Name:            dlfree
+      - Index:           16
+        Name:            calloc
+      - Index:           17
+        Name:            _Exit
+      - Index:           18
+        Name:            __main_void
+      - Index:           19
+        Name:            __wasi_args_get
+      - Index:           20
+        Name:            __wasi_args_sizes_get
+      - Index:           21
+        Name:            __wasi_proc_exit
+      - Index:           22
+        Name:            abort
+      - Index:           23
+        Name:            sbrk
+      - Index:           24
+        Name:            dummy
+      - Index:           25
+        Name:            __wasm_call_dtors
+      - Index:           26
+        Name:            memset
+    GlobalNames:
+      - Index:           0
+        Name:            __stack_pointer
+      - Index:           1
+        Name:            GOT.data.internal.__memory_base
+    DataSegmentNames:
+      - Index:           0
+        Name:            .rodata
+      - Index:           1
+        Name:            .data
+      - Index:           2
+        Name:            swift5_protocols
+      - Index:           3
+        Name:            swift5_protocol_conformances
+      - Index:           4
+        Name:            swift5_type_metadata
+      - Index:           5
+        Name:            swift5_fieldmd
+      - Index:           6
+        Name:            swift5_builtin
+      - Index:           7
+        Name:            swift5_assocty
+      - Index:           8
+        Name:            swift5_capture
+      - Index:           9
+        Name:            swift5_reflstr
+      - Index:           10
+        Name:            swift5_typeref
+      - Index:           11
+        Name:            swift5_mpenum
+      - Index:           12
+        Name:            swift5_replace
+      - Index:           13
+        Name:            swift5_replac2
+      - Index:           14
+        Name:            swift5_accessible_functions
+      - Index:           15
+        Name:            swift5_runtime_attributes
+      - Index:           16
+        Name:            swift5_tests
+      - Index:           17
+        Name:            swift5_entry
+      - Index:           18
+        Name:            .swift_modhash
+  - Type:            CUSTOM
+    Name:            producers
+    Languages:
+      - Name:            C_plus_plus_14
+        Version:         ''
+    Tools:
+      - Name:            clang
+        Version:         '17.0.0 (https://github.com/swiftlang/llvm-project.git b9d3d72e441c70ab8c463d615e36db1df685151b)'
+  - Type:            CUSTOM
+    Name:            target_features
+    Features:
+      - Prefix:          USED
+        Name:            bulk-memory
+      - Prefix:          USED
+        Name:            multivalue
+      - Prefix:          USED
+        Name:            mutable-globals
+      - Prefix:          USED
+        Name:            reference-types
+      - Prefix:          USED
+        Name:            sign-ext
+...
diff --git a/test/Reflection/box_descriptor_with_element_archetype.swift b/test/Reflection/box_descriptor_with_element_archetype.swift
new file mode 100644
index 0000000000000..36c0d9cc51f2b
--- /dev/null
+++ b/test/Reflection/box_descriptor_with_element_archetype.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend -emit-ir %s -target %target-swift-5.9-abi-triple
+
+public protocol P {}
+
+public struct G<T>: P {
+  let s1: String
+  let s2: String
+}
+
+public func f<each T>(t: repeat G<each T>) {
+    var ts: [any P] = []
+    for x in repeat each t {
+        ts.append(x)
+    }
+}
diff --git a/test/Reflection/capture_descriptors.sil b/test/Reflection/capture_descriptors.sil
index 3d30b3ec01e96..ea48bc0b36223 100644
--- a/test/Reflection/capture_descriptors.sil
+++ b/test/Reflection/capture_descriptors.sil
@@ -9,6 +9,12 @@
 // RUN: %target-build-swift %s -emit-module -emit-library -module-name capture_descriptors -o %t/capture_descriptors%{target-shared-library-suffix} -L%t/../../.. -lBlocksRuntime
 // RUN: %target-swift-reflection-dump %t/capture_descriptors%{target-shared-library-suffix} | %FileCheck %s
 
+// lld on FreeBSD relocates some of the metadata sections resulting in invalid
+// offsets in section headers, breaking the Swift reflection data ELF parser
+// resulting in missing metadata.
+// rdar://159139154
+// XFAIL: OS=freebsd
+
 sil_stage canonical
 
 import Builtin
diff --git a/test/Reflection/conformance_descriptors.swift b/test/Reflection/conformance_descriptors.swift
index b114f76455280..9c88d445c5e72 100644
--- a/test/Reflection/conformance_descriptors.swift
+++ b/test/Reflection/conformance_descriptors.swift
@@ -2,9 +2,6 @@
 //
 // LC_DYLD_CHAINED_FIXUPS decode not currently supported (default on visionOS)
 // UNSUPPORTED: OS=xros
-//
-// Temporarily disable on AArch64 Linux (rdar://88451721)
-// UNSUPPORTED: OS=linux-gnu && CPU=aarch64
 
 // rdar://100558042
 // UNSUPPORTED: CPU=arm64e
diff --git a/test/Reflection/typeref_decoding.swift b/test/Reflection/typeref_decoding.swift
index e0a3b4465a39e..ebe65b8aafa4f 100644
--- a/test/Reflection/typeref_decoding.swift
+++ b/test/Reflection/typeref_decoding.swift
@@ -8,9 +8,6 @@
 
 // RUN: %empty-directory(%t)
 
-// FIXME: rdar://127796117
-// UNSUPPORTED: OS=linux-gnu && CPU=aarch64
-
 // RUN: %target-build-swift -target %target-swift-5.2-abi-triple -Xfrontend -enable-anonymous-context-mangled-names %S/Inputs/ConcreteTypes.swift %S/Inputs/GenericTypes.swift %S/Inputs/Protocols.swift %S/Inputs/Extensions.swift %S/Inputs/Closures.swift -parse-as-library -emit-module -emit-library %no-fixup-chains -module-name TypesToReflect -o %t/%target-library-name(TypesToReflect)
 // RUN: %target-build-swift -target %target-swift-5.2-abi-triple -Xfrontend -enable-anonymous-context-mangled-names %S/Inputs/ConcreteTypes.swift %S/Inputs/GenericTypes.swift %S/Inputs/Protocols.swift %S/Inputs/Extensions.swift %S/Inputs/Closures.swift %S/Inputs/main.swift -emit-module -emit-executable %no-fixup-chains -module-name TypesToReflect -o %t/TypesToReflect
 
diff --git a/test/Reflection/typeref_decoding_asan.swift b/test/Reflection/typeref_decoding_asan.swift
index 0e7d4498a3619..8cf10fa802285 100644
--- a/test/Reflection/typeref_decoding_asan.swift
+++ b/test/Reflection/typeref_decoding_asan.swift
@@ -6,7 +6,7 @@
 
 // REQUIRES: asan_runtime
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift -target %target-swift-5.2-abi-triple %S/Inputs/ConcreteTypes.swift %S/Inputs/GenericTypes.swift %S/Inputs/Protocols.swift %S/Inputs/Extensions.swift %S/Inputs/Closures.swift -parse-as-library -emit-module -emit-library -module-name TypesToReflect -sanitize=address -o %t/%target-library-name(TypesToReflect)
+// RUN: %target-build-swift -target %target-swift-5.2-abi-triple %S/Inputs/ConcreteTypes.swift %S/Inputs/GenericTypes.swift %S/Inputs/Protocols.swift %S/Inputs/Extensions.swift %S/Inputs/Closures.swift -parse-as-library -emit-module -emit-library -module-name TypesToReflect %no-fixup-chains -sanitize=address -o %t/%target-library-name(TypesToReflect)
 // RUN: %target-swift-reflection-dump %t/%target-library-name(TypesToReflect) | %FileCheck %s
 
 // CHECK: FIELDS:
diff --git a/test/Reflection/typeref_decoding_imported.swift b/test/Reflection/typeref_decoding_imported.swift
index 82efcf7b9b1ab..a06656f71e7d5 100644
--- a/test/Reflection/typeref_decoding_imported.swift
+++ b/test/Reflection/typeref_decoding_imported.swift
@@ -23,6 +23,12 @@
 
 // UNSUPPORTED: OS=linux-android, OS=linux-androideabi
 
+// lld on FreeBSD relocates some of the metadata sections resulting in invalid
+// offsets in section headers, breaking the Swift reflection data ELF parser
+// resulting in missing metadata.
+// rdar://159139154
+// XFAIL: OS=freebsd
+
 // CHECK-32: FIELDS:
 // CHECK-32: =======
 // CHECK-32: TypesToReflect.HasCTypes
diff --git a/test/Reflection/typeref_decoding_packs.swift b/test/Reflection/typeref_decoding_packs.swift
new file mode 100644
index 0000000000000..29e5a0bb505c0
--- /dev/null
+++ b/test/Reflection/typeref_decoding_packs.swift
@@ -0,0 +1,175 @@
+// REQUIRES: no_asan
+//
+// LC_DYLD_CHAINED_FIXUPS decode not currently supported (default on visionOS)
+// UNSUPPORTED: OS=xros
+//
+// rdar://100805115
+// UNSUPPORTED: CPU=arm64e
+
+// RUN: %empty-directory(%t)
+
+// FIXME: rdar://127796117
+// UNSUPPORTED: OS=linux-gnu && CPU=aarch64
+
+// RUN: %target-build-swift -target %target-swift-5.9-abi-triple %S/Inputs/Packs.swift -parse-as-library -emit-module -emit-library %no-fixup-chains -module-name TypesToReflect -o %t/%target-library-name(TypesToReflect)
+// RUN: %target-build-swift -target %target-swift-5.9-abi-triple %S/Inputs/Packs.swift -emit-module -emit-executable %no-fixup-chains -module-name TypesToReflect -o %t/TypesToReflect
+
+// RUN: %target-swift-reflection-dump %t/%target-library-name(TypesToReflect) | %FileCheck %s
+// RUN: %target-swift-reflection-dump %t/TypesToReflect | %FileCheck %s
+
+// CHECK: FIELDS:
+// CHECK: =======
+// CHECK: TypesToReflect.Packed
+// CHECK: ---------------------
+// CHECK: tuple1: (repeat A)
+// CHECK: (tuple
+// CHECK:   (pack_expansion
+// CHECK:     (pattern
+// CHECK:       (generic_type_parameter depth=0 index=0)
+// CHECK:     (count
+// CHECK:       (generic_type_parameter depth=0 index=0)))
+
+// CHECK: tuple2: (repeat (A) -> ())
+// CHECK: (tuple
+// CHECK:   (pack_expansion
+// CHECK:     (pattern
+// CHECK:       (function
+// CHECK:         (parameters
+// CHECK:           (generic_type_parameter depth=0 index=0)
+// CHECK:         (result
+// CHECK:           (tuple))
+// CHECK:     (count
+// CHECK:       (generic_type_parameter depth=0 index=0)))
+
+// CHECK: tuple3: (repeat TypesToReflect.Scalar<A>)
+// CHECK: (tuple
+// CHECK:   (pack_expansion
+// CHECK:     (pattern
+// CHECK:       (bound_generic_struct TypesToReflect.Scalar
+// CHECK:         (generic_type_parameter depth=0 index=0))
+// CHECK:     (count
+// CHECK:       (generic_type_parameter depth=0 index=0)))
+
+// CHECK: tuple4: (repeat Swift.Int)
+// CHECK: (tuple
+// CHECK:   (pack_expansion
+// CHECK:     (pattern
+// CHECK:       (struct Swift.Int)
+// CHECK:     (count
+// CHECK:       (generic_type_parameter depth=0 index=0)))
+
+// CHECK: func1: (repeat A) -> ()
+// CHECK: (function
+// CHECK:   (parameters
+// CHECK:     (pack_expansion
+// CHECK:       (pattern
+// CHECK:         (generic_type_parameter depth=0 index=0)
+// CHECK:       (count
+// CHECK:         (generic_type_parameter depth=0 index=0))
+// CHECK:   (result
+// CHECK:     (tuple))
+
+// CHECK: func2: (repeat TypesToReflect.Scalar<A>) -> ()
+// CHECK: (function
+// CHECK:   (parameters
+// CHECK:     (pack_expansion
+// CHECK:       (pattern
+// CHECK:         (bound_generic_struct TypesToReflect.Scalar
+// CHECK:           (generic_type_parameter depth=0 index=0))
+// CHECK:       (count
+// CHECK:         (generic_type_parameter depth=0 index=0))
+// CHECK:   (result
+// CHECK:     (tuple))
+
+// CHECK: func3: (repeat Swift.Int) -> ()
+// CHECK: (function
+// CHECK:   (parameters
+// CHECK:     (pack_expansion
+// CHECK:       (pattern
+// CHECK:         (struct Swift.Int)
+// CHECK:       (count
+// CHECK:         (generic_type_parameter depth=0 index=0))
+// CHECK:   (result
+// CHECK:     (tuple))
+
+// CHECK: nominal1: TypesToReflect.AlsoPacked<Pack{repeat A}>
+// CHECK: (bound_generic_struct TypesToReflect.AlsoPacked
+// CHECK:   (pack
+// CHECK:     (pack_expansion
+// CHECK:       (pattern
+// CHECK:         (generic_type_parameter depth=0 index=0)
+// CHECK:       (count
+// CHECK:         (generic_type_parameter depth=0 index=0))))
+
+// CHECK: nominal2: TypesToReflect.AlsoPacked<Pack{repeat TypesToReflect.Scalar<A>}>
+// CHECK: (bound_generic_struct TypesToReflect.AlsoPacked
+// CHECK:   (pack
+// CHECK:     (pack_expansion
+// CHECK:       (pattern
+// CHECK:         (bound_generic_struct TypesToReflect.Scalar
+// CHECK:           (generic_type_parameter depth=0 index=0))
+// CHECK:       (count
+// CHECK:         (generic_type_parameter depth=0 index=0))))
+
+// CHECK: nominal3: TypesToReflect.AlsoPacked<Pack{repeat Swift.Int}>
+// CHECK: (bound_generic_struct TypesToReflect.AlsoPacked
+// CHECK:   (pack
+// CHECK:     (pack_expansion
+// CHECK:       (pattern
+// CHECK:         (struct Swift.Int)
+// CHECK:       (count
+// CHECK:         (generic_type_parameter depth=0 index=0))))
+
+// CHECK: TypesToReflect.AlsoPacked
+// CHECK: -------------------------
+// CHECK: t: (repeat A)
+// CHECK: (tuple
+// CHECK:   (pack_expansion
+// CHECK:     (pattern
+// CHECK:       (generic_type_parameter depth=0 index=0)
+// CHECK:     (count
+// CHECK:       (generic_type_parameter depth=0 index=0)))
+
+// CHECK: TypesToReflect.NestedPacked
+// CHECK: ---------------------------
+// CHECK: t: (repeat TypesToReflect.Packed<Pack{repeat A1}, A>)
+// CHECK: (tuple
+// CHECK:   (pack_expansion
+// CHECK:     (pattern
+// CHECK:       (bound_generic_struct TypesToReflect.Packed
+// CHECK:         (pack
+// CHECK:           (pack_expansion
+// CHECK:             (pattern
+// CHECK:               (generic_type_parameter depth=1 index=0)
+// CHECK:             (count
+// CHECK:               (generic_type_parameter depth=1 index=0)))
+// CHECK:         (generic_type_parameter depth=0 index=0))
+// CHECK:     (count
+// CHECK:       (generic_type_parameter depth=0 index=0)))
+
+// CHECK: u: (repeat TypesToReflect.AlsoPacked<Pack{repeat A1, A}>)
+// CHECK: (tuple
+// CHECK:   (pack_expansion
+// CHECK:     (pattern
+// CHECK:       (bound_generic_struct TypesToReflect.AlsoPacked
+// CHECK:         (pack
+// CHECK:           (pack_expansion
+// CHECK:             (pattern
+// CHECK:               (generic_type_parameter depth=1 index=0)
+// CHECK:             (count
+// CHECK:               (generic_type_parameter depth=1 index=0))
+// CHECK:           (generic_type_parameter depth=0 index=0)))
+// CHECK:     (count
+// CHECK:       (generic_type_parameter depth=0 index=0)))
+
+// CHECK: ASSOCIATED TYPES:
+// CHECK: =================
+// CHECK: - TypesToReflect.AlsoPacked : TypesToReflect.P
+// CHECK: typealias A = (repeat A)
+// CHECK: (repeat A)
+// CHECK: (tuple
+// CHECK:   (pack_expansion
+// CHECK:     (pattern
+// CHECK:       (generic_type_parameter depth=0 index=0)
+// CHECK:     (count
+// CHECK:       (generic_type_parameter depth=0 index=0)))
\ No newline at end of file
diff --git a/test/Reflection/typeref_lowering_packs.swift b/test/Reflection/typeref_lowering_packs.swift
new file mode 100644
index 0000000000000..3e3795b8c9690
--- /dev/null
+++ b/test/Reflection/typeref_lowering_packs.swift
@@ -0,0 +1,309 @@
+// REQUIRES: no_asan
+//
+// LC_DYLD_CHAINED_FIXUPS decode not currently supported (default on visionOS)
+// UNSUPPORTED: OS=xros
+//
+// RUN: %empty-directory(%t)
+
+// rdar://100558042
+// UNSUPPORTED: CPU=arm64e
+
+// RUN: %target-build-swift -target %target-swift-5.9-abi-triple %S/Inputs/Packs.swift -parse-as-library -emit-module -emit-library %no-fixup-chains -module-name TypeLowering -o %t/%target-library-name(TypesToReflect)
+// RUN: %target-build-swift -target %target-swift-5.9-abi-triple %S/Inputs/Packs.swift %S/Inputs/main.swift -emit-module -emit-executable %no-fixup-chains -module-name TypeLowering -o %t/TypesToReflect
+
+// RUN: %target-swift-reflection-dump %t/%target-library-name(TypesToReflect) %platform-module-dir/%target-library-name(swiftCore) -dump-type-lowering < %s | %FileCheck %s
+// RUN: %target-swift-reflection-dump %t/TypesToReflect %platform-module-dir/%target-library-name(swiftCore) -dump-type-lowering < %s | %FileCheck %s
+
+// REQUIRES: PTRSIZE=64
+
+12TypeLowering6SimpleV
+
+// CHECK: (struct TypeLowering.Simple)
+// CHECK: (struct size=52 alignment=8 stride=56 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:   (field name=x1 offset=0
+// CHECK:     (struct size=4 alignment=4 stride=4 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:       (field name=t offset=0
+// CHECK:         (struct size=4 alignment=4 stride=4 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=_value offset=0
+// CHECK:             (builtin size=4 alignment=4 stride=4 num_extra_inhabitants=0 bitwise_takable=1))))))
+// CHECK:   (field name=x2 offset=8
+// CHECK:     (struct size=12 alignment=8 stride=16 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:       (field name=t offset=0
+// CHECK:         (tuple size=12 alignment=8 stride=16 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field offset=0
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:           (field offset=8
+// CHECK:             (struct size=4 alignment=4 stride=4 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=4 alignment=4 stride=4 num_extra_inhabitants=0 bitwise_takable=1))))))))
+// CHECK:   (field name=x3 offset=24
+// CHECK:     (struct size=28 alignment=8 stride=32 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:       (field name=t offset=0
+// CHECK:         (tuple size=28 alignment=8 stride=32 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field offset=0
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:           (field offset=8
+// CHECK:             (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:               (field name=_guts offset=0
+// CHECK:                 (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                   (field name=_object offset=0
+// CHECK:                     (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                       (field name=_countAndFlagsBits offset=0
+// CHECK:                         (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                           (field name=_value offset=0
+// CHECK:                             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:                       (field name=_object offset=8
+// CHECK:                         (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))))))))
+// CHECK:           (field offset=24
+// CHECK:             (struct size=4 alignment=4 stride=4 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=4 alignment=4 stride=4 num_extra_inhabitants=0 bitwise_takable=1)))))))))
+
+12TypeLowering7ComplexV
+
+// CHECK: (struct TypeLowering.Complex)
+// CHECK: (struct size=368 alignment=8 stride=368 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:   (field name=x1 offset=0
+// CHECK:     (struct size=48 alignment=8 stride=48 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:       (field name=tuple1 offset=0
+// CHECK:         (tuple size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1))
+// CHECK:       (field name=tuple2 offset=0
+// CHECK:         (tuple size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1))
+// CHECK:       (field name=tuple3 offset=0
+// CHECK:         (tuple size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1))
+// CHECK:       (field name=tuple4 offset=0
+// CHECK:         (tuple size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1))
+// CHECK:       (field name=func1 offset=0
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=func2 offset=16
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=func3 offset=32
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=nominal1 offset=48
+// CHECK:         (struct size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (tuple size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:       (field name=nominal2 offset=48
+// CHECK:         (struct size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (tuple size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:       (field name=nominal3 offset=48
+// CHECK:         (struct size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (tuple size=0 alignment=1 stride=1 num_extra_inhabitants=0 bitwise_takable=1))))))
+// CHECK:   (field name=x2 offset=48
+// CHECK:     (struct size=112 alignment=8 stride=112 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:       (field name=tuple1 offset=0
+// CHECK:         (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=_value offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:       (field name=tuple2 offset=8
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=tuple3 offset=24
+// CHECK:         (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))))
+// CHECK:       (field name=tuple4 offset=32
+// CHECK:         (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=_value offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:       (field name=func1 offset=40
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=func2 offset=56
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=func3 offset=72
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=nominal1 offset=88
+// CHECK:         (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))))
+// CHECK:       (field name=nominal2 offset=96
+// CHECK:         (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=t offset=0
+// CHECK:                 (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                   (field name=_value offset=0
+// CHECK:                     (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))))))
+// CHECK:       (field name=nominal3 offset=104
+// CHECK:         (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))))))
+// CHECK:   (field name=x3 offset=160
+// CHECK:     (struct size=208 alignment=8 stride=208 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:       (field name=tuple1 offset=0
+// CHECK:         (tuple size=24 alignment=8 stride=24 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field offset=0
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:           (field offset=8
+// CHECK:             (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:               (field name=_guts offset=0
+// CHECK:                 (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                   (field name=_object offset=0
+// CHECK:                     (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                       (field name=_countAndFlagsBits offset=0
+// CHECK:                         (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                           (field name=_value offset=0
+// CHECK:                             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:                       (field name=_object offset=8
+// CHECK:                         (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))))))))))
+// CHECK:       (field name=tuple2 offset=24
+// CHECK:         (tuple size=32 alignment=8 stride=32 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field offset=0
+// CHECK:             (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:               (field name=function offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:               (field name=context offset=8
+// CHECK:                 (reference kind=strong refcounting=native))))
+// CHECK:           (field offset=16
+// CHECK:             (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:               (field name=function offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:               (field name=context offset=8
+// CHECK:                 (reference kind=strong refcounting=native))))))
+// CHECK:       (field name=tuple3 offset=56
+// CHECK:         (tuple size=24 alignment=8 stride=24 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field offset=0
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=t offset=0
+// CHECK:                 (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                   (field name=_value offset=0
+// CHECK:                     (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))))
+// CHECK:           (field offset=8
+// CHECK:             (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:               (field name=t offset=0
+// CHECK:                 (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                   (field name=_guts offset=0
+// CHECK:                     (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                       (field name=_object offset=0
+// CHECK:                         (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                           (field name=_countAndFlagsBits offset=0
+// CHECK:                             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                               (field name=_value offset=0
+// CHECK:                                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:                           (field name=_object offset=8
+// CHECK:                             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))))))))))))
+// CHECK:       (field name=tuple4 offset=80
+// CHECK:         (tuple size=16 alignment=8 stride=16 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field offset=0
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:           (field offset=8
+// CHECK:             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field name=_value offset=0
+// CHECK:                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))))
+// CHECK:       (field name=func1 offset=96
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=func2 offset=112
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=func3 offset=128
+// CHECK:         (thick_function size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=function offset=0
+// CHECK:             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))
+// CHECK:           (field name=context offset=8
+// CHECK:             (reference kind=strong refcounting=native))))
+// CHECK:       (field name=nominal1 offset=144
+// CHECK:         (struct size=24 alignment=8 stride=24 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (tuple size=24 alignment=8 stride=24 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:               (field offset=0
+// CHECK:                 (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                   (field name=_value offset=0
+// CHECK:                     (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:               (field offset=8
+// CHECK:                 (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                   (field name=_guts offset=0
+// CHECK:                     (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                       (field name=_object offset=0
+// CHECK:                         (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                           (field name=_countAndFlagsBits offset=0
+// CHECK:                             (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                               (field name=_value offset=0
+// CHECK:                                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:                           (field name=_object offset=8
+// CHECK:                             (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))))))))))))
+// CHECK:       (field name=nominal2 offset=168
+// CHECK:         (struct size=24 alignment=8 stride=24 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (tuple size=24 alignment=8 stride=24 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:               (field offset=0
+// CHECK:                 (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                   (field name=t offset=0
+// CHECK:                     (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                       (field name=_value offset=0
+// CHECK:                         (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))))
+// CHECK:               (field offset=8
+// CHECK:                 (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                   (field name=t offset=0
+// CHECK:                     (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                       (field name=_guts offset=0
+// CHECK:                         (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                           (field name=_object offset=0
+// CHECK:                             (struct size=16 alignment=8 stride=16 num_extra_inhabitants={{.*}} bitwise_takable=1
+// CHECK:                               (field name=_countAndFlagsBits offset=0
+// CHECK:                                 (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                                   (field name=_value offset=0
+// CHECK:                                     (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:                               (field name=_object offset=8
+// CHECK:                                 (builtin size=8 alignment=8 stride=8 num_extra_inhabitants={{.*}} bitwise_takable=1))))))))))))))
+// CHECK:       (field name=nominal3 offset=192
+// CHECK:         (struct size=16 alignment=8 stride=16 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:           (field name=t offset=0
+// CHECK:             (tuple size=16 alignment=8 stride=16 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:               (field offset=0
+// CHECK:                 (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                   (field name=_value offset=0
+// CHECK:                     (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1))))
+// CHECK:               (field offset=8
+// CHECK:                 (struct size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1
+// CHECK:                   (field name=_value offset=0
+// CHECK:                     (builtin size=8 alignment=8 stride=8 num_extra_inhabitants=0 bitwise_takable=1)))))))))))
\ No newline at end of file
diff --git a/test/Reflection/wasm.test b/test/Reflection/wasm.test
new file mode 100644
index 0000000000000..98c904795dcc6
--- /dev/null
+++ b/test/Reflection/wasm.test
@@ -0,0 +1,28 @@
+# RUN: %yaml2obj %S/Inputs/wasm.yaml -o %t.wasm
+# RUN: %target-swift-reflection-dump --arch=wasi --no-objc-interop %t.wasm | %FileCheck %s
+#
+# CHECK: FIELDS
+# CHECK: t:
+# CHECK: ASSOCIATED TYPES
+# CHECK: -  : simple.P
+# CHECK: typealias A = Builtin.Int32
+# CHECK: Builtin.Int32
+# CHECK: (builtin Builtin.Int32)
+#
+# simple.swift
+# protocol P { associatedtype A }
+# struct T {}
+# struct S : P {
+#   typealias A = Builtin.Int32
+#   let t: T
+# }
+# sys.c
+# void swift_addNewDSOImage() {}
+#
+# compiled for -target wasm32-unknown-wasip1
+# obj2yaml simple.o -o simple.o.yaml
+# (replace UNDEFINED symbol with a definition)
+# obj2yaml simple.o.yaml -o simple-mod.o
+# swiftc simple-mod.o sys.o -o simple.wasm
+# yaml2obj simple.wasm -o simple-mod.o
+#
diff --git a/test/Runtime/associated_type_demangle_private.swift b/test/Runtime/associated_type_demangle_private.swift
index c54c7e8b15814..21adec77b9232 100644
--- a/test/Runtime/associated_type_demangle_private.swift
+++ b/test/Runtime/associated_type_demangle_private.swift
@@ -101,14 +101,9 @@ private struct Parent<Unused> {
 
 AssociatedTypeDemangleTests.test("nested private generic types in associated type witnesses") {
   // Fixed in Swift 5.1+ runtimes.
-  if #available(SwiftStdlib 5.1, *) {}
-  // Bug is still present in Swift 5.0 runtime.
-  else {
-    expectCrashLater(withMessage: "failed to demangle witness for associated type 'Second' in conformance")
-    return
+  if #available(SwiftStdlib 5.1, *) {
+    _ = Parent<Never>.Nested(first: "String", second: 0).pair
   }
-
-  _ = Parent<Never>.Nested(first: "String", second: 0).pair
 }
 
 
diff --git a/test/Runtime/backtrace.swift b/test/Runtime/backtrace.swift
index 19ac684128b7b..14e5de6301b41 100644
--- a/test/Runtime/backtrace.swift
+++ b/test/Runtime/backtrace.swift
@@ -10,6 +10,7 @@
 // UNSUPPORTED: OS=watchos
 // UNSUPPORTED: OS=ios
 // UNSUPPORTED: OS=tvos
+// UNSUPPORTED: OS=linux-android, OS=linux-androideabi
 
 // REQUIRES: swift_stdlib_asserts
 // REQUIRES: executable_test
diff --git a/test/Runtime/protocol-conformance-cache-objc.swift b/test/Runtime/protocol-conformance-cache-objc.swift
new file mode 100644
index 0000000000000..3c2eedfbe7fc0
--- /dev/null
+++ b/test/Runtime/protocol-conformance-cache-objc.swift
@@ -0,0 +1,51 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -o %t/a.out
+// RUN: env %env-SWIFT_DEBUG_ENABLE_PROTOCOL_CONFORMANCES_LOOKUP_LOG=1 %target-run %t/a.out 2>&1 | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: objc_interop
+// REQUIRES: swift_stdlib_asserts
+// UNSUPPORTED: DARWIN_SIMULATOR=ios
+// UNSUPPORTED: DARWIN_SIMULATOR=tvos
+// UNSUPPORTED: DARWIN_SIMULATOR=watchos
+// UNSUPPORTED: DARWIN_SIMULATOR=xros
+// UNSUPPORTED: use_os_stdlib
+
+// The optimizer will remove many of these conformance checks due to statically
+// knowing the result.
+// UNSUPPORTED: swift_test_mode_optimize
+// UNSUPPORTED: swift_test_mode_optimize_size
+
+import Foundation
+
+protocol Proto {}
+extension Proto {
+  static var selfType: Any.Type { Self.self }
+}
+
+func conformsToProto<T>(_ type: T.Type) -> Bool {
+  (type as? Proto.Type)?.selfType == type
+}
+
+func doesNotConformToProto<T>(_ type: T) -> Bool {
+  (type as? Proto.Type) == nil
+}
+
+@objc class BaseClass: NSObject, Proto {}
+@objc class DerivedClass: BaseClass {}
+@objc class NonConformingClass: NSObject {}
+
+// CHECK: Check confomance a.BaseClass to Proto: found, source: section scan
+assert(conformsToProto(BaseClass.self))
+// CHECK: Check confomance a.BaseClass to Proto: found, source: cache by type metadata
+assert(conformsToProto(BaseClass.self))
+
+// CHECK: Check confomance a.DerivedClass to Proto: found, source: section scan
+assert(conformsToProto(DerivedClass.self))
+// CHECK: Check confomance a.DerivedClass to Proto: found, source: cache by type metadata
+assert(conformsToProto(DerivedClass.self))
+
+// CHECK: Check confomance a.NonConformingClass to Proto: not found, source: section scan
+assert(doesNotConformToProto(NonConformingClass.self))
+// CHECK: Check confomance a.NonConformingClass to Proto: not found, source: cache by type metadata
+assert(doesNotConformToProto(NonConformingClass.self))
diff --git a/test/Runtime/protocol-conformance-cache.swift b/test/Runtime/protocol-conformance-cache.swift
new file mode 100644
index 0000000000000..20ab6c76b6477
--- /dev/null
+++ b/test/Runtime/protocol-conformance-cache.swift
@@ -0,0 +1,121 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -o %t/a.out
+// RUN: env %env-SWIFT_DEBUG_ENABLE_PROTOCOL_CONFORMANCES_LOOKUP_LOG=1 %target-run %t/a.out 2>&1 | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: swift_stdlib_asserts
+// UNSUPPORTED: DARWIN_SIMULATOR=ios
+// UNSUPPORTED: DARWIN_SIMULATOR=tvos
+// UNSUPPORTED: DARWIN_SIMULATOR=watchos
+// UNSUPPORTED: DARWIN_SIMULATOR=xros
+// UNSUPPORTED: use_os_stdlib
+
+// The optimizer will remove many of these conformance checks due to statically
+// knowing the result.
+// UNSUPPORTED: swift_test_mode_optimize
+// UNSUPPORTED: swift_test_mode_optimize_size
+
+protocol Proto {}
+extension Proto {
+  static var selfType: Any.Type { Self.self }
+}
+
+func conformsToProto<T>(_ type: T.Type) -> Bool {
+  (type as? Proto.Type)?.selfType == type
+}
+
+func doesNotConformToProto<T>(_ type: T) -> Bool {
+  (type as? Proto.Type) == nil
+}
+
+extension Array: Proto {}
+extension Dictionary: Proto where Key: Proto {}
+extension Int: Proto {}
+
+// CHECK: Check confomance Swift.Int to Proto: found, source: section scan
+assert(conformsToProto(Int.self))
+// CHECK: Check confomance Swift.Int to Proto: found, source: cache by type metadata
+assert(conformsToProto(Int.self))
+
+// CHECK: Check confomance Swift.String to Proto: not found, source: section scan
+assert(doesNotConformToProto(String.self))
+// CHECK: Check confomance Swift.String to Proto: not found, source: cache by type metadata
+assert(doesNotConformToProto(String.self))
+
+// CHECK: Check confomance Swift.Array<Swift.Int> to Proto: found, source: section scan
+assert(conformsToProto([Int].self))
+// CHECK: Check confomance Swift.Array<Swift.Int> to Proto: found, source: cache by type metadata
+assert(conformsToProto([Int].self))
+
+// CHECK: Check confomance Swift.Array<Swift.String> to Proto: found, source: cache by type descriptor
+assert(conformsToProto([String].self))
+// CHECK: Check confomance Swift.Array<Swift.String> to Proto: found, source: cache by type metadata
+assert(conformsToProto([String].self))
+
+// CHECK: Check confomance Swift.Dictionary<Swift.Int, Swift.Int> to Proto: found, source: section scan
+assert(conformsToProto([Int: Int].self))
+
+// CHECK: Check confomance Swift.Dictionary<Swift.String, Swift.Int> to Proto: not found, source: cache by type descriptor
+assert(doesNotConformToProto([String: Int].self))
+// CHECK: Check confomance Swift.Dictionary<Swift.String, Swift.Int> to Proto: not found, source: cache by type metadata
+assert(doesNotConformToProto([String: Int].self))
+
+
+class BaseClass: Proto {}
+class DerivedClass: BaseClass {}
+class GenericClass<T>: Proto {}
+class GenericClassConditional<T> {}
+extension GenericClassConditional: Proto where T: Proto {}
+
+// CHECK: Check confomance a.BaseClass to Proto: found, source: section scan
+assert(conformsToProto(BaseClass.self))
+// CHECK: Check confomance a.BaseClass to Proto: found, source: cache by type metadata
+assert(conformsToProto(BaseClass.self))
+
+// CHECK: Check confomance a.DerivedClass to Proto: found, source: section scan
+assert(conformsToProto(DerivedClass.self))
+// CHECK: Check confomance a.DerivedClass to Proto: found, source: cache by type metadata
+assert(conformsToProto(DerivedClass.self))
+
+// CHECK: Check confomance a.GenericClass<Swift.Int> to Proto: found, source: section scan
+assert(conformsToProto(GenericClass<Int>.self))
+// CHECK: Check confomance a.GenericClass<Swift.Int> to Proto: found, source: cache by type metadata
+assert(conformsToProto(GenericClass<Int>.self))
+
+// CHECK: Check confomance a.GenericClass<Swift.String> to Proto: found, source: cache by type descriptor
+assert(conformsToProto(GenericClass<String>.self))
+// CHECK: Check confomance a.GenericClass<Swift.String> to Proto: found, source: cache by type metadata
+assert(conformsToProto(GenericClass<String>.self))
+
+// CHECK: Check confomance a.GenericClassConditional<Swift.Int> to Proto: found, source: section scan
+assert(conformsToProto(GenericClassConditional<Int>.self))
+// CHECK: Check confomance a.GenericClassConditional<Swift.Int> to Proto: found, source: cache by type metadata
+assert(conformsToProto(GenericClassConditional<Int>.self))
+
+// CHECK: Check confomance a.GenericClassConditional<Swift.String> to Proto: not found, source: cache by type descriptor
+assert(doesNotConformToProto(GenericClassConditional<String>.self))
+// CHECK: Check confomance a.GenericClassConditional<Swift.String> to Proto: not found, source: cache by type metadata
+assert(doesNotConformToProto(GenericClassConditional<String>.self))
+
+enum Enum: Proto {}
+extension Optional: Proto where Wrapped: Proto {}
+
+// CHECK: Check confomance a.Enum to Proto: found, source: section scan
+assert(conformsToProto(Enum.self))
+// CHECK: Check confomance a.Enum to Proto: found, source: cache by type metadata
+assert(conformsToProto(Enum.self))
+
+// CHECK: Check confomance Swift.Optional<a.Enum> to Proto: found, source: section scan
+assert(conformsToProto(Enum?.self))
+// CHECK: Check confomance Swift.Optional<a.Enum> to Proto: found, source: cache by type metadata
+assert(conformsToProto(Enum?.self))
+
+// CHECK: Check confomance Swift.Optional<Swift.Int> to Proto: found, source: cache by type descriptor
+assert(conformsToProto(Int?.self))
+// CHECK: Check confomance Swift.Optional<Swift.Int> to Proto: found, source: cache by type metadata
+assert(conformsToProto(Int?.self))
+
+// CHECK: Check confomance Swift.Optional<Swift.String> to Proto: not found, source: cache by type descriptor
+assert(doesNotConformToProto(String?.self))
+// CHECK: Check confomance Swift.Optional<Swift.String> to Proto: not found, source: cache by type metadata
+assert(doesNotConformToProto(String?.self))
diff --git a/test/SIL/OwnershipVerifier/borrow_accessor.sil b/test/SIL/OwnershipVerifier/borrow_accessor.sil
new file mode 100644
index 0000000000000..e6ac48f9daa17
--- /dev/null
+++ b/test/SIL/OwnershipVerifier/borrow_accessor.sil
@@ -0,0 +1,165 @@
+// RUN: %target-sil-opt -disable-swift-verification -sil-ownership-verifier-enable-testing -ownership-verifier-textual-error-dumper -enable-sil-verify-all=0 %s -o /dev/null 2>&1 | %FileCheck %s
+// REQUIRES: asserts
+
+class Klass {}
+
+public struct Wrapper {
+  @_hasStorage var _k: Klass { get set }
+  var k: Klass
+}
+
+public struct GenWrapper<T> {
+  @_hasStorage var _prop: T { get set }
+  public var prop: T
+}
+
+sil [ossa] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+bb0(%0 : @guaranteed $Wrapper):
+  %2 = struct_extract %0, #Wrapper._k             
+  return %2                                       
+}
+
+sil [ossa] @borrow_addressonly_prop : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed_addr T {
+bb0(%0 : $*GenWrapper<T>):
+  %2 = struct_element_addr %0, #GenWrapper._prop  
+  return %2                                       
+}
+
+sil @get_wrapper : $@convention(thin) () -> @owned Klass
+sil @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+sil @use_T : $@convention(thin) <T> (@in_guaranteed T) -> ()
+
+// CHECK-LABEL: Error#: 0. Begin Error in Function: 'test_end_borrow_on_guaranteed_return_value'
+// CHECK: Invalid End Borrow!
+// CHECK: Original Value:   %1 = begin_borrow %0 : $Wrapper
+// CHECK: End Borrow:   end_borrow %3 : $Klass
+// CHECK-LABEL: Error#: 0. End Error in Function: 'test_end_borrow_on_guaranteed_return_value'
+// CHECK-LABEL: Error#: 1. Begin Error in Function: 'test_end_borrow_on_guaranteed_return_value'
+// CHECK: Subobject projection with lifetime ending uses!
+// CHECK: Value:   %3 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK: Lifetime Ending User:   end_borrow %3 : $Klass
+// CHECK-LABEL: Error#: 1. End Error in Function: 'test_end_borrow_on_guaranteed_return_value'
+sil [ossa] @test_end_borrow_on_guaranteed_return_value : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  %1 = begin_borrow %0
+  %2 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %3 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  end_borrow %3
+  end_borrow %1
+  destroy_value %0
+  %10 = tuple ()
+  return %10
+}
+
+// CHECK-LABEL: Error#: 0. Begin Error in Function: 'test_inconsistent_guaranteed_phi1'
+// CHECK: Invalid End Borrow!
+// CHECK: Original Value:   %1 = begin_borrow %0 : $Wrapper
+// CHECK: End Borrow:   br bb3(%4 : $Klass)
+// CHECK-LABEL: Error#: 0. End Error in Function: 'test_inconsistent_guaranteed_phi1'
+// CHECK-LABEL: Error#: 1. Begin Error in Function: 'test_inconsistent_guaranteed_phi1'
+// CHECK: Subobject projection with lifetime ending uses!
+// CHECK: Value:   %4 = apply %3(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK: Lifetime Ending User:   br bb3(%4 : $Klass)
+// CHECK-LABEL: Error#: 1. End Error in Function: 'test_inconsistent_guaranteed_phi1'
+sil [ossa] @test_inconsistent_guaranteed_phi1 : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  %1 = begin_borrow %0
+  cond_br undef, bb1, bb2
+
+bb1:
+  %3 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %4 = apply %3(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  br bb3(%4)
+
+bb2:
+  %6 = struct_extract %1, #Wrapper._k
+  %7 = begin_borrow %6
+  br bb3(%7)
+
+bb3(%9 : @reborrow $Klass):
+  %10 = borrowed %9 from (%1)
+  end_borrow %10
+  end_borrow %1
+  destroy_value %0
+  %14 = tuple ()
+  return %14
+}
+
+// CHECK-LABEL: Error#: 0. Begin Error in Function: 'test_inconsistent_guaranteed_phi2'
+// CHECK: Non trivial values, non address values, and non guaranteed function args must have at least one lifetime ending use?!
+// CHECK: Value:   %7 = begin_borrow %6 : $Klass
+// CHECK-LABEL: Error#: 0. End Error in Function: 'test_inconsistent_guaranteed_phi2'
+sil [ossa] @test_inconsistent_guaranteed_phi2 : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  %1 = begin_borrow %0
+  cond_br undef, bb1, bb2
+
+bb1:
+  %3 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %4 = apply %3(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  br bb3(%4)
+
+bb2:
+  %6 = struct_extract %1, #Wrapper._k
+  %7 = begin_borrow %6
+  br bb3(%7)
+
+bb3(%9 : @guaranteed $Klass):
+  end_borrow %1
+  destroy_value %0
+  %12 = tuple ()
+  return %12
+}
+
+// CHECK: Error#: 0. Begin Error in Function: 'test_use_after_free_loadable1'
+// CHECK: Have operand with incompatible ownership?!
+// CHECK: Value: %0 = argument of bb0 : $Wrapper
+// CHECK: User:   %2 = apply %1(%0) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK: Operand Number: 1
+// CHECK: Conv: owned
+// CHECK: Constraint:
+// CHECK: <Constraint Kind:guaranteed LifetimeConstraint:NonLifetimeEnding>
+// CHECK: Error#: 0. End Error in Function: 'test_use_after_free_loadable1'
+sil [ossa] @test_use_after_free_loadable1 : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  %1 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %2 = apply %1(%0) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  destroy_value %0
+  %4 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %5 = apply %4(%2) : $@convention(thin) (@guaranteed Klass) -> ()
+  %6 = tuple ()
+  return %6
+}
+
+// CHECK: Error#: 0. Begin Error in Function: 'test_use_after_free_loadable2'
+// CHECK: Found outside of lifetime use?!
+// CHECK: Value:   %1 = begin_borrow %0 : $Wrapper
+// CHECK: Consuming User:   end_borrow %1 : $Wrapper
+// CHECK: Non Consuming User:   %6 = apply %5(%3) : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK: Block: bb0
+// CHECK: Error#: 0. End Error in Function: 'test_use_after_free_loadable2'
+sil [ossa] @test_use_after_free_loadable2 : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  %1 = begin_borrow %0
+  %2 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %3 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  end_borrow %1
+  %4 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %5 = apply %4(%3) : $@convention(thin) (@guaranteed Klass) -> ()
+  destroy_value %0
+  %6 = tuple ()
+  return %6
+}
+
+// TODO: Add verification support in MemoryLifetimeVerifier
+sil [ossa] @test_use_after_free_address_only : $@convention(thin) <T> (@in GenWrapper<T>) -> () {
+bb0(%0 : $*GenWrapper<T>):
+  %1 = function_ref @borrow_addressonly_prop : $@convention(method) <τ_0_0> (@in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+  %2 = apply %1<T>(%0) : $@convention(method) <τ_0_0> (@in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+  %3 = function_ref @use_T : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  destroy_addr %0
+  %5 = apply %3<T>(%2) : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  %6 = tuple ()
+  return %6
+}
+
diff --git a/test/SIL/OwnershipVerifier/use_verifier.sil b/test/SIL/OwnershipVerifier/use_verifier.sil
index aa6744e38a5a3..66c0a1725e7ce 100644
--- a/test/SIL/OwnershipVerifier/use_verifier.sil
+++ b/test/SIL/OwnershipVerifier/use_verifier.sil
@@ -828,30 +828,6 @@ bb5(%5 : @owned $ThreeDifferingPayloadEnum):
   return %5 : $ThreeDifferingPayloadEnum
 }
 
-sil [ossa] @enum_cases_with_trivial_unowned_cases_arg_into_phi : $@convention(thin) (Builtin.NativeObject) -> ThreeDifferingPayloadEnum {
-bb0(%0 : @unowned $Builtin.NativeObject):
-  cond_br undef, bb1, bb2
-
-bb1:
-  cond_br undef, bb3, bb4
-
-bb2:
-  %1 = enum $ThreeDifferingPayloadEnum, #ThreeDifferingPayloadEnum.nopayload!enumelt
-  br bb5(%1 : $ThreeDifferingPayloadEnum)
-
-bb3:
-  %2 = enum $ThreeDifferingPayloadEnum, #ThreeDifferingPayloadEnum.nontrivial_payload!enumelt, %0 : $Builtin.NativeObject
-  br bb5(%2 : $ThreeDifferingPayloadEnum)
-
-bb4:
-  %3 = integer_literal $Builtin.Int32, 0
-  %4 = enum $ThreeDifferingPayloadEnum, #ThreeDifferingPayloadEnum.trivial_payload!enumelt, %3 : $Builtin.Int32
-  br bb5(%4 : $ThreeDifferingPayloadEnum)
-
-bb5(%5 : @unowned $ThreeDifferingPayloadEnum):
-  return %5 : $ThreeDifferingPayloadEnum
-}
-
 sil [ossa] @enum_cases_with_trivial_guaranteed_cases_arg_into_phi : $@convention(thin) (@guaranteed Builtin.NativeObject) -> @owned ThreeDifferingPayloadEnum {
 bb0(%0 : @guaranteed $Builtin.NativeObject):
   cond_br undef, bb1, bb2
@@ -1383,20 +1359,6 @@ bb3(%fUnknown : @owned $@callee_owned () -> ()):
   return %9999 : $()
 }
 
-sil [ossa] @unowned_to_ref_is_unowned_instant_use : $@convention(thin) (@guaranteed Builtin.NativeObject) -> Builtin.NativeObject {
-bb0(%0 : @guaranteed $Builtin.NativeObject):
-  %1 = ref_to_unowned %0 : $Builtin.NativeObject to $@sil_unowned Builtin.NativeObject
-  %2 = unowned_to_ref %1 : $@sil_unowned Builtin.NativeObject to $Builtin.NativeObject
-  return %2 : $Builtin.NativeObject
-}
-
-sil [ossa] @unmanaged_to_ref_is_unowned_instant_use : $@convention(thin) (@guaranteed Builtin.NativeObject) -> Builtin.NativeObject {
-bb0(%0 : @guaranteed $Builtin.NativeObject):
-  %1 = ref_to_unmanaged %0 : $Builtin.NativeObject to $@sil_unmanaged Builtin.NativeObject
-  %2 = unmanaged_to_ref %1 : $@sil_unmanaged Builtin.NativeObject to $Builtin.NativeObject
-  return %2 : $Builtin.NativeObject
-}
-
 sil [ossa] @nontrivial_enum_unchecked_enum_data_trivial_payload_owned : $@convention(thin) (@owned ThreeDifferingPayloadEnum) -> Builtin.Int32 {
 bb0(%0 : @owned $ThreeDifferingPayloadEnum):
   // NOTE: It may be surprising that %0 is consumed by this unchecked_enum_data
diff --git a/test/SIL/Parser/actor_isolation.sil b/test/SIL/Parser/actor_isolation.sil
new file mode 100644
index 0000000000000..fc315037ae150
--- /dev/null
+++ b/test/SIL/Parser/actor_isolation.sil
@@ -0,0 +1,39 @@
+// RUN: %target-sil-opt -sil-print-function-isolation-info -enable-objc-interop -enable-sil-verify-all=true %s | %target-sil-opt -sil-print-function-isolation-info -enable-objc-interop -enable-sil-verify-all=true | %FileCheck %s
+
+// REQUIRES: asserts
+
+// CHECK: // func_with_caller_isolation_inheriting
+// CHECK: // Isolation: caller_isolation_inheriting
+// CHECK: sil [isolation "caller_isolation_inheriting"] @func_with_caller_isolation_inheriting : $@convention(thin) () -> () {
+sil [isolation "caller_isolation_inheriting"] @func_with_caller_isolation_inheriting : $@convention(thin) () -> () {
+bb0:
+  %0 = tuple ()
+  return %0 : $()
+}
+
+// CHECK: // func_with_global_actor_isolation
+// CHECK: // Isolation: global_actor. type: <null>
+// CHECK: sil [isolation "global_actor"] @func_with_global_actor_isolation : $@convention(thin) () -> () {
+sil [isolation "global_actor"] @func_with_global_actor_isolation : $@convention(thin) () -> () {
+bb0:
+  %0 = tuple ()
+  return %0 : $()
+}
+
+// CHECK: // func_with_actor_instance_isolation
+// CHECK: // Isolation: actor_instance
+// CHECK: sil [isolation "actor_instance"] @func_with_actor_instance_isolation : $@convention(thin) () -> () {
+sil [isolation "actor_instance"] @func_with_actor_instance_isolation : $@convention(thin) () -> () {
+bb0:
+  %0 = tuple ()
+  return %0 : $()
+}
+
+// CHECK: // func_with_nonisolated_isolation
+// CHECK: // Isolation: nonisolated
+// CHECK: sil [isolation "nonisolated"] @func_with_nonisolated_isolation : $@convention(thin) () -> () {
+sil [isolation "nonisolated"] @func_with_nonisolated_isolation : $@convention(thin) () -> () {
+bb0:
+  %0 = tuple ()
+  return %0 : $()
+}
\ No newline at end of file
diff --git a/test/SIL/Parser/basic.sil b/test/SIL/Parser/basic.sil
index 2af0a635ce4d1..3289b1dbf5ea6 100644
--- a/test/SIL/Parser/basic.sil
+++ b/test/SIL/Parser/basic.sil
@@ -1220,6 +1220,16 @@ sil @alloc_stack_test : $() -> () {
 // CHECK: } // end sil function 'alloc_stack_test'
 }
 
+// CHECK-LABEL: sil @vector_base_addr :
+// CHECK:         %1 = vector_base_addr %0 : $*Builtin.FixedArray<10, Int>
+// CHECK-LABEL: } // end sil function 'vector_base_addr'
+sil @vector_base_addr : $@convention(thin) (@inout Builtin.FixedArray<10, Int>) -> Int {
+bb0(%0 : $*Builtin.FixedArray<10, Int>):
+  %1 = vector_base_addr %0
+  %2 = load %1
+  return %2
+}
+
 sil_global @staticProp: $Int
 
 // CHECK-LABEL: sil private @globalinit_func0 : $@convention(thin) () -> () {
@@ -1734,6 +1744,36 @@ bb0:
   return %1 : $()
 }
 
+protocol P2 {
+  associatedtype A
+}
+
+// CHECK-LABEL: sil [ossa] @test_dependent_existential_archetype :
+// CHECK:         %2 = alloc_stack $(@opened("0B7C132E-8010-11F0-8526-0EA13E3AABB4", any P2) Self).A
+// CHECK-LABEL: } // end sil function 'test_dependent_existential_archetype'
+sil [ossa] @test_dependent_existential_archetype : $@convention(thin) (@thick any P2.Type) -> () {
+bb0(%0 : $@thick any P2.Type):
+  %1 = open_existential_metatype %0 to $@thick (@opened("0B7C132E-8010-11F0-8526-0EA13E3AABB4", any P2) Self).Type
+  %2 = alloc_stack $(@opened("0B7C132E-8010-11F0-8526-0EA13E3AABB4", any P2) Self).A
+  dealloc_stack %2
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil [heuristic_always_inline] @heuristic_always_inline_attribute
+sil [heuristic_always_inline] @heuristic_always_inline_attribute : $@convention(thin) () -> () {
+bb0:
+  %0 = tuple ()
+  return %0 : $()
+}
+
+// CHECK-LABEL: sil [always_inline] @always_inline_attribute
+sil [always_inline] @always_inline_attribute : $@convention(thin) () -> () {
+bb0:
+  %0 = tuple ()
+  return %0 : $()
+}
+
 class Foo2: Foo {}
 
 // CHECK-LABEL: sil_vtable Foo {
@@ -1763,4 +1803,3 @@ sil_vtable GenKlass {
 // CHECK-LABEL: sil_vtable $GenKlass<Int> {
 sil_vtable $GenKlass<Int> {
 }
-
diff --git a/test/SIL/Parser/basic2_noncopyable_generics.sil b/test/SIL/Parser/basic2_noncopyable_generics.sil
index 092986d125f0d..91530e23ed2db 100644
--- a/test/SIL/Parser/basic2_noncopyable_generics.sil
+++ b/test/SIL/Parser/basic2_noncopyable_generics.sil
@@ -1,15 +1,15 @@
 // RUN: %target-sil-opt                                      \
 // RUN:     %s                                               \
-// RUN:     -enable-experimental-feature LifetimeDependence   \
+// RUN:     -enable-experimental-feature Lifetimes   \
 // RUN: |                                                    \
 // RUN: %target-sil-opt                                      \
-// RUN:     -enable-experimental-feature LifetimeDependence   \
+// RUN:     -enable-experimental-feature Lifetimes   \
 // RUN: |                                                    \
 // RUN: %FileCheck %s
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
-// For -enable-experimental-feature LifetimeDependence
+// For -enable-experimental-feature Lifetimes
 
 // TODO: Once NoncopyableGenerics/NonescapableTypes is no longer behind a feature flag, merge this into basic2.
 
@@ -29,7 +29,7 @@ struct NCG<T> : ~Copyable {
 // CHECK-NEXT:    var t: T
 struct NEG<T : ~Escapable> : ~Escapable {
   var t: T
-  @lifetime(copy t)
+  @_lifetime(copy t)
   init(_ t: consuming T) {
     self.t = t
   }
diff --git a/test/SIL/Parser/borrow_accessor.sil b/test/SIL/Parser/borrow_accessor.sil
new file mode 100644
index 0000000000000..44e1adb15286b
--- /dev/null
+++ b/test/SIL/Parser/borrow_accessor.sil
@@ -0,0 +1,58 @@
+// RUN: %target-sil-opt %s | %FileCheck %s
+
+class Klass {}
+
+public struct Wrapper {
+  @_hasStorage var _k: Klass { get set }
+  var k: Klass
+}
+
+public struct GenWrapper<T> {
+  @_hasStorage var _prop: T { get set }
+  public var prop: T
+}
+
+// CHECK-LABEL: sil [ossa] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+sil [ossa] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+bb0(%0 : @guaranteed $Wrapper):
+  %2 = struct_extract %0, #Wrapper._k             
+  return %2                                       
+}
+
+// CHECK-LABEL: sil [ossa] @borrow_addressonly_prop : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed_addr T {
+sil [ossa] @borrow_addressonly_prop : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed_addr T {
+bb0(%0 : $*GenWrapper<T>):
+  %2 = struct_element_addr %0, #GenWrapper._prop  
+  return %2                                       
+}
+
+sil @get_wrapper : $@convention(thin) () -> @owned Klass
+sil @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+sil @use_T : $@convention(thin) <T> (@in_guaranteed T) -> ()
+
+sil [ossa] @test1 : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  %1 = begin_borrow %0
+  %2 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %3 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %4 = copy_value %3
+  %5 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %6 = apply %5(%4) : $@convention(thin) (@guaranteed Klass) -> ()
+  destroy_value %4
+  end_borrow %1
+  destroy_value %0
+  %10 = tuple ()
+  return %10
+}
+
+sil [ossa] @test2 : $@convention(thin) <T> (@in GenWrapper<T>) -> () {
+bb0(%0 : $*GenWrapper<T>):
+  %1 = function_ref @borrow_addressonly_prop : $@convention(method) <τ_0_0> (@in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+  %2 = apply %1<T>(%0) : $@convention(method) <τ_0_0> (@in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+  %3 = function_ref @use_T : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  %4 = apply %3<T>(%2) : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> ()
+  destroy_addr %0
+  %6 = tuple ()
+  return %6
+}
+
diff --git a/test/SIL/Parser/lifetime_dependence.sil b/test/SIL/Parser/lifetime_dependence.sil
index 594bc3341dc5c..dd44268201ca1 100644
--- a/test/SIL/Parser/lifetime_dependence.sil
+++ b/test/SIL/Parser/lifetime_dependence.sil
@@ -1,8 +1,8 @@
 // RUN: %target-sil-opt %s \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN: | %FileCheck %s
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 sil_stage canonical
 
@@ -11,14 +11,14 @@ import Swift
 
 struct BufferView : ~Escapable {
   @_hasStorage let ptr: UnsafeRawBufferPointer { get }
-  @lifetime(borrow ptr) @inlinable init(_ ptr: UnsafeRawBufferPointer) 
-  @lifetime(borrow a) init(_ ptr: UnsafeRawBufferPointer, _ a: borrowing Array<Int>) 
+  @_lifetime(borrow ptr) @inlinable init(_ ptr: UnsafeRawBufferPointer) 
+  @_lifetime(borrow a) init(_ ptr: UnsafeRawBufferPointer, _ a: borrowing Array<Int>) 
 }
 
-@lifetime(borrow x) 
+@_lifetime(borrow x) 
 func derive(_ x: borrowing BufferView) -> BufferView
 
-@lifetime(copy x)
+@_lifetime(copy x)
 func consumeAndCreate(_ x: consuming BufferView) -> BufferView
 
 sil hidden [unsafe_nonescapable_result] @bufferviewinit1 : $@convention(method) (UnsafeRawBufferPointer, @thin BufferView.Type) -> @owned BufferView {
diff --git a/test/SIL/Parser/witness_protocol_from_import.sil b/test/SIL/Parser/witness_protocol_from_import.sil
index 7e417e71e2b0c..4f3556730dcdd 100644
--- a/test/SIL/Parser/witness_protocol_from_import.sil
+++ b/test/SIL/Parser/witness_protocol_from_import.sil
@@ -10,7 +10,7 @@ enum X {
   case twotransp
 }
 
-sil @_TTWO5test21Xs9EquatableS_FS1_oi2eeUS1___fMQPS1_FT3lhsS2_3rhsS2__Sb : $@convention(witness_method: Equatable) (@in X, @in X, @thick X.Type) -> Bool {
+sil @_TTWO5test21Xs9EquatableS_FS1_oi2eeUS1___fMQPS1_FT3lhsS2_3rhsS2__Sb : $@convention(witness_method: Equatable) (@in_guaranteed X, @in_guaranteed X, @thick X.Type) -> Bool {
 bb0(%0 : $*X, %1 : $*X, %2 : $@thick X.Type):
   %3 = load %0 : $*X
   %4 = load %1 : $*X
@@ -21,10 +21,9 @@ bb0(%0 : $*X, %1 : $*X, %2 : $@thick X.Type):
 }
 
 
-sil @_TTWO5test21Xs8HashableS_FS1_g9hashValueSi : $@convention(witness_method: Hashable) (@inout X) -> Int {
+sil @_TTWO5test21Xs8HashableS_FS1_g9hashValueSi : $@convention(witness_method: Hashable) (@in_guaranteed X) -> Int {
 bb0(%0 : $*X):
   %1 = load %0 : $*X
-
   %2 = function_ref @_TFO5test21Xg9hashValueSi : $@convention(method) (X) -> Int
   %3 = apply %2(%1) : $@convention(method) (X) -> Int
   return %3 : $Int
diff --git a/test/SIL/Parser/witness_tables.sil b/test/SIL/Parser/witness_tables.sil
index 7a9ac26e7fa5d..446172bd07166 100644
--- a/test/SIL/Parser/witness_tables.sil
+++ b/test/SIL/Parser/witness_tables.sil
@@ -15,7 +15,7 @@ bb0(%0 : $ConformingAssoc):
   return %2 : $()
 }
 
-sil @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_ : $@convention(witness_method: AssocReqt) (@inout ConformingAssoc) -> () {
+sil @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_ : $@convention(witness_method: AssocReqt) (@in_guaranteed ConformingAssoc) -> () {
 bb0(%0 : $*ConformingAssoc):
   %1 = load %0 : $*ConformingAssoc
   %2 = function_ref @_TFV14witness_tables15ConformingAssoc14requiredMethodfS0_FT_T_ : $@convention(method) (ConformingAssoc) -> ()
@@ -30,6 +30,13 @@ sil_witness_table ConformingAssoc: AssocReqt module witness_tables {
   method #AssocReqt.requiredMethod: @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_
 }
 
+// CHECK-LABEL: sil_witness_table [specialized] ConformingAssoc: AssocReqt module witness_tables {
+// CHECK: #AssocReqt.requiredMethod: {{.*}} : @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_
+// CHECK: }
+sil_witness_table [specialized] ConformingAssoc: AssocReqt module witness_tables {
+  method #AssocReqt.requiredMethod: @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_
+}
+
 protocol AnyProtocol {
   associatedtype AssocType
   associatedtype AssocWithReqt : AssocReqt
diff --git a/test/SIL/Serialization/effects.sil b/test/SIL/Serialization/effects.sil
new file mode 100644
index 0000000000000..5774f8453d88c
--- /dev/null
+++ b/test/SIL/Serialization/effects.sil
@@ -0,0 +1,31 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -module-name=NonLE -emit-module -o %t/NonLE.swiftmodule
+// RUN: %target-swift-frontend %s -module-name=LE -enable-library-evolution -emit-module -o %t/LE.swiftmodule
+// RUN: %target-sil-opt %t/NonLE.swiftmodule | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NONLE
+// RUN: %target-sil-opt %t/LE.swiftmodule | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-LE
+
+sil_stage canonical
+
+import Swift
+import Builtin
+
+// CHECK-LABEL:      sil [serialized] [canonical] [ossa] @public_func :
+// CHECK-NONLE-NEXT: [global: ]
+// CHECK-NEXT:       bb0:
+sil [serialized] [ossa] @public_func : $@convention(thin) () -> () {
+[global: ]
+bb0:
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL:      sil non_abi [serialized] [canonical] [ossa] @public_non_abi_func :
+// CHECK-NEXT:       [global: ]
+// CHECK-NEXT:       bb0:
+sil non_abi [serialized] [ossa] @public_non_abi_func : $@convention(thin) () -> () {
+[global: ]
+bb0:
+  %r = tuple ()
+  return %r
+}
+
diff --git a/test/SIL/Serialization/literals.sil b/test/SIL/Serialization/literals.sil
index 93d0d02f5b286..8de63242ebe37 100644
--- a/test/SIL/Serialization/literals.sil
+++ b/test/SIL/Serialization/literals.sil
@@ -14,6 +14,10 @@ bb0:
   %4 = string_literal bytes "ABCD"
 // CHECK: string_literal oslog "os log section"
   %5 = string_literal oslog "os log section"
-  %6 = tuple ()
-  return %6 : $()
+// CHECK: string_literal utf8 "abc\0def"
+  %6 = string_literal utf8 "abc\0def"
+// CHECK: string_literal utf8 "xyz\0"
+  %7 = string_literal utf8 "xyz\0"
+  %8 = tuple ()
+  return %8 : $()
 }
diff --git a/test/SIL/Serialization/shared_function_serialization.sil b/test/SIL/Serialization/shared_function_serialization.sil
index 40c85f5a569b4..ad8fe95ac2974 100644
--- a/test/SIL/Serialization/shared_function_serialization.sil
+++ b/test/SIL/Serialization/shared_function_serialization.sil
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend %S/Inputs/shared_function_serialization_input.swift -o %t/Swift.swiftmodule -emit-module -parse-as-library -parse-stdlib -module-link-name swiftCore -module-name Swift -O -enable-ossa-modules
-// RUN: %target-sil-opt -enable-sil-verify-all -I %t -performance-linker -enable-ossa-modules -inline %s -o - | %FileCheck %s
+// RUN: %target-swift-frontend %S/Inputs/shared_function_serialization_input.swift -o %t/Swift.swiftmodule -emit-module -parse-as-library -parse-stdlib -module-link-name swiftCore -module-name Swift -O
+// RUN: %target-sil-opt -enable-sil-verify-all -I %t -performance-linker -inline %s -o - | %FileCheck %s
 
 // CHECK: sil private @top_level_code
 // CHECK: sil public_external [serialized] [ossa] @$ss1XVABycfC{{.*}}
diff --git a/test/SIL/Serialization/witness_tables.sil b/test/SIL/Serialization/witness_tables.sil
index f4504d0f3bc89..369a2beece710 100644
--- a/test/SIL/Serialization/witness_tables.sil
+++ b/test/SIL/Serialization/witness_tables.sil
@@ -15,7 +15,7 @@ bb0(%0 : $ConformingAssoc):
   return %2 : $()
 }
 
-sil [serialized] @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_ : $@convention(witness_method: AssocReqt) (@inout ConformingAssoc) -> () {
+sil [serialized] @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_ : $@convention(witness_method: AssocReqt) (@in_guaranteed ConformingAssoc) -> () {
 bb0(%0 : $*ConformingAssoc):
   %1 = load %0 : $*ConformingAssoc
   %2 = function_ref @_TFV14witness_tables15ConformingAssoc14requiredMethodfS0_FT_T_ : $@convention(method) (ConformingAssoc) -> ()
@@ -30,6 +30,13 @@ sil_witness_table [serialized] ConformingAssoc: AssocReqt module witness_tables
   method #AssocReqt.requiredMethod: @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_
 }
 
+// CHECK-LABEL: sil_witness_table [serialized] [specialized] ConformingAssoc: AssocReqt module witness_tables {
+// CHECK: #AssocReqt.requiredMethod: {{.*}} : @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_
+// CHECK: }
+sil_witness_table [serialized] [specialized] ConformingAssoc: AssocReqt module witness_tables {
+  method #AssocReqt.requiredMethod: @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_
+}
+
 protocol AnyProtocol {
   associatedtype AssocType
   associatedtype AssocWithReqt : AssocReqt
diff --git a/test/SIL/borrow_accessor_e2e.swift b/test/SIL/borrow_accessor_e2e.swift
new file mode 100644
index 0000000000000..13c29288ea8ca
--- /dev/null
+++ b/test/SIL/borrow_accessor_e2e.swift
@@ -0,0 +1,68 @@
+// RUN: %empty-directory(%t) 
+// RUN: %target-build-swift %s -emit-executable -enable-experimental-feature BorrowAndMutateAccessors -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+// REQUIRES: executable_test
+
+public struct Container<Element: ~Copyable >: ~Copyable {
+  var _storage: UnsafeMutableBufferPointer<Element>
+  var _count: Int
+
+  var first: Element {
+    @_unsafeSelfDependentResult
+    borrow {
+      return _storage.baseAddress.unsafelyUnwrapped.pointee
+    }
+    @_unsafeSelfDependentResult
+    mutate {
+      return &_storage.baseAddress.unsafelyUnwrapped.pointee
+    }
+  }
+
+  public subscript(index: Int) -> Element {
+    @_unsafeSelfDependentResult
+    borrow {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return _storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee
+    }
+    @_unsafeSelfDependentResult
+    mutate {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return &_storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee
+    }
+  }
+}
+
+extension Container: Copyable where Element: Copyable {}
+
+func test() {
+  let n = 10_000
+  var arr = Array(0...n)
+  let count = arr.count
+  let sum = arr.withUnsafeMutableBufferPointer { ubpointer in
+    let container = Container(_storage: ubpointer, _count: count)
+    var sum = 0
+    for i in 0..<container._count {
+      sum &+= container[i]
+    }
+    return sum
+  }
+  let expectedSum = n * (n + 1) / 2
+  assert(sum == expectedSum)
+  let mutated_sum = arr.withUnsafeMutableBufferPointer { ubpointer in
+    var container = Container(_storage: ubpointer, _count: count)
+    var sum = 0
+    for i in 0..<container._count {
+      container[i] &+= 1
+      sum += container[i]
+    }
+    return sum
+  }
+  let mutatedExpectedSum = (n + 1) * (n + 2) / 2
+  assert(mutated_sum == mutatedExpectedSum)
+}
+
+test()
+
diff --git a/test/SIL/clang-function-types-android.swift b/test/SIL/clang-function-types-android.swift
index 1d5d82baff56f..0685eba73c44a 100644
--- a/test/SIL/clang-function-types-android.swift
+++ b/test/SIL/clang-function-types-android.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -emit-sil -swift-version 5 -use-clang-function-types -experimental-print-full-convention -o - | %FileCheck %s --check-prefix=CHECK-%target-ptrsize
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -Xllvm -sil-print-types -emit-sil -swift-version 5 -use-clang-function-types -experimental-print-full-convention -o - | %FileCheck %s --check-prefix=CHECK-%target-ptrsize
 
 // REQUIRES: OS=linux-android ||  OS=linux-androideabi
 
diff --git a/test/SIL/cloning-inline-always.sil b/test/SIL/cloning-inline-always.sil
new file mode 100644
index 0000000000000..fc9e8cac70dc6
--- /dev/null
+++ b/test/SIL/cloning-inline-always.sil
@@ -0,0 +1,308 @@
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all -inline %s | %FileCheck %s
+
+// Check cloning of instructions.
+
+sil_stage canonical
+
+import Builtin
+
+class X {
+}
+
+sil [always_inline] @callee_alloc_ref_stack : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_ref [stack] $X
+  dealloc_stack_ref %0 : $X
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil @caller_alloc_ref_stack : $@convention(thin) () -> ()
+// CHECK: [[X:%[0-9]+]] = alloc_ref [stack] $X
+// CHECK: dealloc_stack_ref [[X]] : $X
+sil @caller_alloc_ref_stack : $@convention(thin) () -> () {
+bb0:
+  %0 = function_ref @callee_alloc_ref_stack : $@convention(thin) () -> ()
+  %1 = apply %0() : $@convention(thin) () -> ()
+  %2 = tuple ()
+  return %2 : $()
+}
+
+sil [ossa] [always_inline] @callee_begin_borrow : $@convention(thin) () -> () {
+  %instance = alloc_ref $X
+  %guaranteed_c = begin_borrow [lexical] %instance : $X
+  end_borrow %guaranteed_c : $X
+  %guaranteed_c2 = begin_borrow [pointer_escape] %instance : $X
+  end_borrow %guaranteed_c2 : $X
+  %guaranteed_c3 = begin_borrow [var_decl] %instance : $X
+  end_borrow %guaranteed_c3 : $X
+  destroy_value %instance : $X
+  %res = tuple ()
+  return %res : $()
+}
+
+// CHECK-LABEL: sil [ossa] @caller_begin_borrow_lexical
+// CHECK: begin_borrow [lexical]
+// CHECK: begin_borrow [pointer_escape]
+// CHECK: begin_borrow [var_decl]
+// CHECK-LABEL: } // end sil function 'caller_begin_borrow_lexical'
+sil [ossa] @caller_begin_borrow_lexical : $@convention(thin) () -> () {
+  %callee_begin_borrow_lexical = function_ref @callee_begin_borrow : $@convention(thin) () -> ()
+  %res = apply %callee_begin_borrow_lexical() : $@convention(thin) () -> ()
+  return %res : $()
+}
+
+sil [ossa] [always_inline] @callee_alloc_box : $@convention(thin) () -> () {
+  %b1 = alloc_box ${ var X }
+  dealloc_box %b1 : ${ var X }
+  %b2 = alloc_box [dynamic_lifetime] ${ var X }
+  dealloc_box %b2 : ${ var X }
+  %b3 = alloc_box [reflection] ${ var X }
+  dealloc_box %b3 : ${ var X }
+  %b4 = alloc_box [pointer_escape] ${ var X }
+  dealloc_box %b4 : ${ var X }
+  %b5 = alloc_box [moveable_value_debuginfo] ${ var X }
+  dealloc_box %b5 : ${ var X }
+  %b6 = alloc_box [dynamic_lifetime] [reflection] ${ var X }
+  dealloc_box %b6 : ${ var X }
+  %b7 = alloc_box [dynamic_lifetime] [pointer_escape] ${ var X }
+  dealloc_box %b7 : ${ var X }
+  %b8 = alloc_box [dynamic_lifetime] [moveable_value_debuginfo] ${ var X }
+  dealloc_box %b8 : ${ var X }
+  %b9 = alloc_box [reflection] [pointer_escape] ${ var X }
+  dealloc_box %b9 : ${ var X }
+  %b10 = alloc_box [reflection] [moveable_value_debuginfo] ${ var X }
+  dealloc_box %b10 : ${ var X }
+  %b11 = alloc_box [pointer_escape] [moveable_value_debuginfo] ${ var X }
+  dealloc_box %b11 : ${ var X }
+  %b12 = alloc_box [reflection] [pointer_escape] [moveable_value_debuginfo] ${ var X }
+  dealloc_box %b12 : ${ var X }
+  %b13 = alloc_box [dynamic_lifetime] [pointer_escape] [moveable_value_debuginfo] ${ var X }
+  dealloc_box %b13 : ${ var X }
+  %b14 = alloc_box [dynamic_lifetime] [reflection] [moveable_value_debuginfo] ${ var X }
+  dealloc_box %b14 : ${ var X }
+  %b15 = alloc_box [dynamic_lifetime] [reflection] [pointer_escape] ${ var X }
+  dealloc_box %b15 : ${ var X }
+  %b16 = alloc_box [dynamic_lifetime] [reflection] [pointer_escape] [moveable_value_debuginfo] ${ var X }
+  dealloc_box %b16 : ${ var X }
+  %res = tuple ()
+  return %res : $()
+}
+
+// CHECK-LABEL: sil [ossa] @caller_alloc_box{{.*}} {
+// CHECK:         alloc_box
+// CHECK:         alloc_box [dynamic_lifetime]
+// CHECK:         alloc_box [reflection]
+// CHECK:         alloc_box [pointer_escape]
+// CHECK:         alloc_box [moveable_value_debuginfo]
+// CHECK:         alloc_box [dynamic_lifetime] [reflection]
+// CHECK:         alloc_box [dynamic_lifetime] [pointer_escape]
+// CHECK:         alloc_box [dynamic_lifetime] [moveable_value_debuginfo]
+// CHECK:         alloc_box [reflection] [pointer_escape]
+// CHECK:         alloc_box [reflection] [moveable_value_debuginfo]
+// CHECK:         alloc_box [pointer_escape] [moveable_value_debuginfo]
+// CHECK:         alloc_box [reflection] [pointer_escape] [moveable_value_debuginfo]
+// CHECK:         alloc_box [dynamic_lifetime] [pointer_escape] [moveable_value_debuginfo]
+// CHECK:         alloc_box [dynamic_lifetime] [reflection] [moveable_value_debuginfo]
+// CHECK:         alloc_box [dynamic_lifetime] [reflection] [pointer_escape]
+// CHECK:         alloc_box [dynamic_lifetime] [reflection] [pointer_escape] [moveable_value_debuginfo]
+// CHECK-LABEL: } // end sil function 'caller_alloc_box'
+sil [ossa] @caller_alloc_box : $@convention(thin) () -> () {
+  %callee = function_ref @callee_alloc_box : $@convention(thin) () -> ()
+  %res = apply %callee() : $@convention(thin) () -> ()
+  return %res : $()
+}
+
+sil [ossa] @callee_alloc_stack : $@convention(thin) () -> () {
+  %instance = alloc_stack $Builtin.NativeObject
+  dealloc_stack %instance : $*Builtin.NativeObject
+  %instance2 = alloc_stack [dynamic_lifetime] $Builtin.NativeObject
+  dealloc_stack %instance2 : $*Builtin.NativeObject
+  %instance3 = alloc_stack [lexical] $Builtin.NativeObject
+  dealloc_stack %instance3 : $*Builtin.NativeObject
+  %instance5 = alloc_stack [var_decl] $Builtin.NativeObject
+  dealloc_stack %instance5 : $*Builtin.NativeObject
+  %instance4 = alloc_stack [lexical] [dynamic_lifetime] $Builtin.NativeObject
+  dealloc_stack %instance4 : $*Builtin.NativeObject
+  %instance6 = alloc_stack [dynamic_lifetime] [var_decl] $Builtin.NativeObject
+  dealloc_stack %instance6 : $*Builtin.NativeObject
+  %instance7 = alloc_stack [lexical] [var_decl] $Builtin.NativeObject
+  dealloc_stack %instance7 : $*Builtin.NativeObject
+  %instance8 = alloc_stack [lexical] [var_decl] [dynamic_lifetime] $Builtin.NativeObject
+  dealloc_stack %instance8 : $*Builtin.NativeObject
+  %res = tuple ()
+  return %res : $()
+}
+
+// CHECK-LABEL: sil [ossa] @caller_alloc_stack_lexical
+// CHECK: alloc_stack
+// CHECK: alloc_stack [dynamic_lifetime]
+// CHECK: alloc_stack [lexical]
+// CHECK: alloc_stack [var_decl]
+// CHECK: alloc_stack [dynamic_lifetime] [lexical]
+// CHECK: alloc_stack [dynamic_lifetime] [var_decl]
+// CHECK: alloc_stack [lexical] [var_decl]
+// CHECK: alloc_stack [dynamic_lifetime] [lexical] [var_decl]
+// CHECK-LABEL: } // end sil function 'caller_alloc_stack_lexical'
+sil [ossa] @caller_alloc_stack_lexical : $@convention(thin) () -> () {
+  %callee_alloc_stack = function_ref @callee_alloc_stack : $@convention(thin) () -> ()
+  %res = apply %callee_alloc_stack() : $@convention(thin) () -> ()
+  return %res : $()
+}
+
+sil [ossa] @callee_move_value : $@convention(thin) (@owned Builtin.NativeObject) -> @owned Builtin.NativeObject {
+entry(%0 : @owned $Builtin.NativeObject):
+  %1 = move_value %0 : $Builtin.NativeObject
+  %2 = move_value [allows_diagnostics] %1 : $Builtin.NativeObject
+  %3 = move_value [lexical] %2 : $Builtin.NativeObject
+  %4 = move_value [allows_diagnostics] [lexical] %3 : $Builtin.NativeObject
+  %5 = move_value [pointer_escape] %4 : $Builtin.NativeObject
+  %6 = move_value [var_decl] %5 : $Builtin.NativeObject
+  return %6 : $Builtin.NativeObject
+}
+
+// CHECK-LABEL: sil [ossa] @caller_move_value {{.*}} {
+// CHECK:       {{bb[0-9]+}}([[REGISTER_0:%[^,]+]] :
+// CHECK:       [[REGISTER_1:%[^,]+]] = move_value [[REGISTER_0]]
+// CHECK:       [[REGISTER_2:%[^,]+]] = move_value [allows_diagnostics] [[REGISTER_1]]
+// CHECK:       [[REGISTER_3:%[^,]+]] = move_value [lexical] [[REGISTER_2]]
+// CHECK:       [[REGISTER_4:%[^,]+]] = move_value [allows_diagnostics] [lexical] [[REGISTER_3]]
+// CHECK:       [[REGISTER_5:%[^,]+]] = move_value [pointer_escape] [[REGISTER_4]]
+// CHECK:       [[REGISTER_6:%[^,]+]] = move_value [var_decl] [[REGISTER_5]]
+// CHECK:       return [[REGISTER_6]]
+// CHECK-LABEL: } // end sil function 'caller_move_value'
+sil [ossa] @caller_move_value : $@convention(thin) (@owned Builtin.NativeObject) -> @owned Builtin.NativeObject {
+entry(%0 : @owned $Builtin.NativeObject):
+  %callee_move_value = function_ref @callee_move_value : $@convention(thin) (@owned Builtin.NativeObject) -> @owned Builtin.NativeObject
+  %res = apply %callee_move_value(%0) : $@convention(thin) (@owned Builtin.NativeObject) -> @owned Builtin.NativeObject
+  return %res : $Builtin.NativeObject
+}
+
+sil [ossa] @callee_debug_value : $@convention(thin) (@owned X) -> @owned X {
+entry(%0 : @owned $X):
+  debug_value [trace] %0 : $X
+  return %0 : $X
+}
+
+sil [ossa] @caller_debug_value : $@convention(thin) (@owned X) -> @owned X {
+entry(%0 : @owned $X):
+  %callee_debug_value = function_ref @callee_debug_value : $@convention(thin) (@owned X) -> @owned X
+  %res = apply %callee_debug_value(%0) : $@convention(thin) (@owned X) -> @owned X
+  return %res : $X
+}
+
+// CHECK-LABEL: sil [ossa] @caller_specify_test : {{.*}} {
+// CHECK:         specify_test "foo bar baz"
+// CHECK-LABEL: } // end sil function 'caller_specify_test'
+sil [always_inline] [ossa] @callee_specify_test : $@convention(thin) () -> () {
+entry:
+  specify_test "foo bar baz"
+  %retval = tuple ()
+  return %retval : $()
+}
+
+sil [ossa] @caller_specify_test : $@convention(thin) () -> () {
+  %callee = function_ref @callee_specify_test : $@convention(thin) () -> ()
+  %retval = apply %callee() : $@convention(thin) () -> ()
+  return %retval : $()
+}
+
+
+// CHECK-LABEL: sil [ossa] @caller_extend_lifetime : {{.*}} {
+// CHECK:       bb0([[O:%[^,]+]] :
+// CHECK:         extend_lifetime [[O]]
+// CHECK-LABEL: } // end sil function 'caller_extend_lifetime'
+sil [always_inline] [ossa] @callee_extend_lifetime : $@convention(thin) (@owned Builtin.NativeObject) -> () {
+entry(%o : @owned $Builtin.NativeObject):
+  br loop
+loop:
+  extend_lifetime %o : $Builtin.NativeObject
+  br loop
+}
+
+sil [ossa] @caller_extend_lifetime : $@convention(thin) (@owned Builtin.NativeObject) -> () {
+entry(%o : @owned $Builtin.NativeObject):
+  %callee = function_ref @callee_extend_lifetime : $@convention(thin) (@owned Builtin.NativeObject) -> ()
+  %retval = apply %callee(%o) : $@convention(thin) (@owned Builtin.NativeObject) -> ()
+  return %retval : $()
+}
+
+sil [ossa] [always_inline] @callee_destroy_value : $@convention(thin) (@owned X) -> () {
+entry(%x : @owned $X):
+  cond_br undef, good, bad
+good:
+  cond_br undef, gleft, gright
+gleft:
+  destroy_value %x : $X
+  br exit
+gright:
+  destroy_value [poison] %x : $X
+  br exit
+exit:
+  %retval = tuple()
+  return %retval : $()
+bad:
+  cond_br undef, bleft, bright
+bleft:
+  destroy_value [dead_end] %x : $X
+  unreachable
+bright:
+  destroy_value [poison] [dead_end] %x : $X
+  unreachable
+}
+
+// CHECK-LABEL: sil [ossa] @caller_destroy_value : {{.*}} {
+// CHECK:         destroy_value
+// CHECK:         destroy_value [poison]
+// CHECK:         destroy_value [dead_end]
+// CHECK:         destroy_value [poison] [dead_end]
+// CHECK-LABEL: } // end sil function 'caller_destroy_value'
+sil [ossa] @caller_destroy_value : $@convention(thin) (@owned X) -> () {
+entry(%x : @owned $X):
+  %callee = function_ref @callee_destroy_value : $@convention(thin) (@owned X) -> ()
+  %res = apply %callee(%x) : $@convention(thin) (@owned X) -> ()
+  return %res : $()
+}
+
+sil [ossa] [always_inline] @callee_dealloc_box : $@convention(thin) () -> () {
+entry:
+  %b = alloc_box ${ var X }
+  cond_br undef, exit, die
+
+exit:
+  dealloc_box %b : ${ var X }
+  %retval = tuple()
+  return %retval : $()
+
+die:
+  dealloc_box [dead_end] %b : ${ var X }
+  unreachable
+}
+
+// CHECK-LABEL: sil [ossa] @caller_dealloc_box : {{.*}} {
+// CHECK:         dealloc_box
+// CHECK:         dealloc_box [dead_end]
+// CHECK-LABEL: } // end sil function 'caller_dealloc_box'
+sil [ossa] @caller_dealloc_box : $@convention(thin) () -> () {
+entry:
+  %callee = function_ref @callee_dealloc_box : $@convention(thin) () -> ()
+  %res = apply %callee() : $@convention(thin) () -> ()
+  return %res : $()
+}
+
+sil [transparent] [ossa] @getSize : $@convention(thin) <Type> (@thick Type.Type) -> Builtin.Word {
+bb0(%ty : $@thick Type.Type):
+  %size = builtin "sizeof"<Type>() : $Builtin.Word
+  return %size : $Builtin.Word
+}
+
+// CHECK-LABEL: sil [ossa] @callee_builtin_type_dep_operand : {{.*}} {
+// CHECK:         open_existential_metatype
+// CHECK-LABEL: } // end sil function 'callee_builtin_type_dep_operand'
+sil [ossa] @callee_builtin_type_dep_operand : $@convention(thin) (@thick any Any.Type) -> Builtin.Word {
+bb0(%0 : $@thick any Any.Type):
+  %ty = open_existential_metatype %0 : $@thick any Any.Type to $@thick (@opened("00000000-0000-0000-0000-000000000000", Any) Self).Type
+  %getSize = function_ref @getSize : $@convention(thin) <τ_0_0> (@thick τ_0_0.Type) -> Builtin.Word
+  %retval = apply %getSize<@opened("00000000-0000-0000-0000-000000000000", Any) Self>(%ty) : $@convention(thin) <τ_0_0> (@thick τ_0_0.Type) -> Builtin.Word
+  return %retval : $Builtin.Word
+}
diff --git a/test/SIL/cloning.sil b/test/SIL/cloning.sil
index fc9e8cac70dc6..cd7a81cd41336 100644
--- a/test/SIL/cloning.sil
+++ b/test/SIL/cloning.sil
@@ -9,7 +9,7 @@ import Builtin
 class X {
 }
 
-sil [always_inline] @callee_alloc_ref_stack : $@convention(thin) () -> () {
+sil [heuristic_always_inline] @callee_alloc_ref_stack : $@convention(thin) () -> () {
 bb0:
   %0 = alloc_ref [stack] $X
   dealloc_stack_ref %0 : $X
@@ -28,7 +28,7 @@ bb0:
   return %2 : $()
 }
 
-sil [ossa] [always_inline] @callee_begin_borrow : $@convention(thin) () -> () {
+sil [ossa] [heuristic_always_inline] @callee_begin_borrow : $@convention(thin) () -> () {
   %instance = alloc_ref $X
   %guaranteed_c = begin_borrow [lexical] %instance : $X
   end_borrow %guaranteed_c : $X
@@ -52,7 +52,7 @@ sil [ossa] @caller_begin_borrow_lexical : $@convention(thin) () -> () {
   return %res : $()
 }
 
-sil [ossa] [always_inline] @callee_alloc_box : $@convention(thin) () -> () {
+sil [ossa] [heuristic_always_inline] @callee_alloc_box : $@convention(thin) () -> () {
   %b1 = alloc_box ${ var X }
   dealloc_box %b1 : ${ var X }
   %b2 = alloc_box [dynamic_lifetime] ${ var X }
@@ -194,7 +194,7 @@ entry(%0 : @owned $X):
 // CHECK-LABEL: sil [ossa] @caller_specify_test : {{.*}} {
 // CHECK:         specify_test "foo bar baz"
 // CHECK-LABEL: } // end sil function 'caller_specify_test'
-sil [always_inline] [ossa] @callee_specify_test : $@convention(thin) () -> () {
+sil [heuristic_always_inline] [ossa] @callee_specify_test : $@convention(thin) () -> () {
 entry:
   specify_test "foo bar baz"
   %retval = tuple ()
@@ -212,7 +212,7 @@ sil [ossa] @caller_specify_test : $@convention(thin) () -> () {
 // CHECK:       bb0([[O:%[^,]+]] :
 // CHECK:         extend_lifetime [[O]]
 // CHECK-LABEL: } // end sil function 'caller_extend_lifetime'
-sil [always_inline] [ossa] @callee_extend_lifetime : $@convention(thin) (@owned Builtin.NativeObject) -> () {
+sil [heuristic_always_inline] [ossa] @callee_extend_lifetime : $@convention(thin) (@owned Builtin.NativeObject) -> () {
 entry(%o : @owned $Builtin.NativeObject):
   br loop
 loop:
@@ -227,7 +227,7 @@ entry(%o : @owned $Builtin.NativeObject):
   return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_destroy_value : $@convention(thin) (@owned X) -> () {
+sil [ossa] [heuristic_always_inline] @callee_destroy_value : $@convention(thin) (@owned X) -> () {
 entry(%x : @owned $X):
   cond_br undef, good, bad
 good:
@@ -264,7 +264,7 @@ entry(%x : @owned $X):
   return %res : $()
 }
 
-sil [ossa] [always_inline] @callee_dealloc_box : $@convention(thin) () -> () {
+sil [ossa] [heuristic_always_inline] @callee_dealloc_box : $@convention(thin) () -> () {
 entry:
   %b = alloc_box ${ var X }
   cond_br undef, exit, die
diff --git a/test/SIL/cloning_opaque_values.sil b/test/SIL/cloning_opaque_values.sil
index 11b2b7423e377..ef5d1f4b3d149 100644
--- a/test/SIL/cloning_opaque_values.sil
+++ b/test/SIL/cloning_opaque_values.sil
@@ -22,7 +22,7 @@ bb0(%instance : @guaranteed $WeakBox<T>):
   return %retval : $Optional<T>
 }
 
-sil [always_inline] [ossa] @strong_copy_weak_value : $@convention(thin) <T where T : AnyObject> (@in_guaranteed WeakBox<T>) -> @owned Optional<T> {
+sil [heuristic_always_inline] [ossa] @strong_copy_weak_value : $@convention(thin) <T where T : AnyObject> (@in_guaranteed WeakBox<T>) -> @owned Optional<T> {
 bb0(%instance : @guaranteed $WeakBox<T>):
   %weak_optional = struct_extract %instance : $WeakBox<T>, #WeakBox.t
   %strong_optional = strong_copy_weak_value %weak_optional : $@sil_weak Optional<T>
@@ -44,7 +44,7 @@ entry(%tuple_addr : $*(repeat each T)):
   return %retval : $()
 }
 
-sil [always_inline] [ossa] @tuple_pack_extract : $@convention(thin) <each T> (@in_guaranteed (repeat each T)) -> () {
+sil [heuristic_always_inline] [ossa] @tuple_pack_extract : $@convention(thin) <each T> (@in_guaranteed (repeat each T)) -> () {
 entry(%tuple_addr : $*(repeat each T)):
   %tuple = load_borrow %tuple_addr : $*(repeat each T)
   %zero = integer_literal $Builtin.Word, 0
@@ -70,7 +70,7 @@ bb0(%value : @owned $Optional<T>):
   return %retval : $WeakBox<T>
 }
 
-sil [always_inline] [ossa] @weak_copy_value : $@convention(thin) <T where T : AnyObject> (@owned Optional<T>) -> @out WeakBox<T> {
+sil [heuristic_always_inline] [ossa] @weak_copy_value : $@convention(thin) <T where T : AnyObject> (@owned Optional<T>) -> @out WeakBox<T> {
 bb0(%value : @owned $Optional<T>):
   %weak_value = weak_copy_value %value : $Optional<T>
   destroy_value %value : $Optional<T>
diff --git a/test/SIL/cloning_opaque_values_objc.sil b/test/SIL/cloning_opaque_values_objc.sil
index d139664829afa..5892579cfe88d 100644
--- a/test/SIL/cloning_opaque_values_objc.sil
+++ b/test/SIL/cloning_opaque_values_objc.sil
@@ -24,7 +24,7 @@ bb0(%value : @owned $T):
   return %retval : $UnownedBox<T>
 }
 
-sil [always_inline] [ossa] @unowned_copy_value : $@convention(thin) <T where T : AnyObject> (@owned T) -> @out UnownedBox<T> {
+sil [heuristic_always_inline] [ossa] @unowned_copy_value : $@convention(thin) <T where T : AnyObject> (@owned T) -> @out UnownedBox<T> {
 bb0(%owned_value : @owned $T):
   %unowned_value = unowned_copy_value %owned_value : $T
   destroy_value %owned_value : $T
diff --git a/test/SIL/explicit_lifetime_dependence_specifiers.swift b/test/SIL/explicit_lifetime_dependence_specifiers.swift
index 1d74064d689ca..2393028abf162 100644
--- a/test/SIL/explicit_lifetime_dependence_specifiers.swift
+++ b/test/SIL/explicit_lifetime_dependence_specifiers.swift
@@ -1,41 +1,17 @@
 // RUN: %target-swift-frontend %s \
 // RUN: -emit-sil  \
 // RUN: -enable-builtin-module \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: | %FileCheck %s
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 import Builtin
 
-@_unsafeNonescapableResult
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, borrowing source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
-
-@_unsafeNonescapableResult
-@lifetime(copy source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, copying source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
-
 struct BufferView : ~Escapable {
   let ptr: UnsafeRawBufferPointer
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers10BufferViewVyACSWcfC : $@convention(method) (UnsafeRawBufferPointer, @thin BufferView.Type) -> @lifetime(borrow 0)  @owned BufferView {
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(_ ptr: UnsafeRawBufferPointer) {
     self.ptr = ptr
   }
@@ -46,22 +22,22 @@ struct BufferView : ~Escapable {
     } 
     self.ptr = ptr
   }
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(independent ptr: UnsafeRawBufferPointer) {
     self.ptr = ptr
   }
  // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers10BufferViewVyACSW_SaySiGhtcfC : $@convention(method) (UnsafeRawBufferPointer, @guaranteed Array<Int>, @thin BufferView.Type) -> @lifetime(borrow 1) @owned BufferView {
-  @lifetime(borrow a)
+  @_lifetime(borrow a)
   init(_ ptr: UnsafeRawBufferPointer, _ a: borrowing Array<Int>) {
     self.ptr = ptr
   }
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers10BufferViewVyACSW_AA7WrapperVtcfC : $@convention(method) (UnsafeRawBufferPointer, @owned Wrapper, @thin BufferView.Type) -> @lifetime(copy 1)  @owned BufferView {
-  @lifetime(copy a)
+  @_lifetime(copy a)
   init(_ ptr: UnsafeRawBufferPointer, _ a: consuming Wrapper) {
     self.ptr = ptr
   }
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers10BufferViewVyACSW_AA7WrapperVSaySiGhtcfC : $@convention(method) (UnsafeRawBufferPointer, @owned Wrapper, @guaranteed Array<Int>, @thin BufferView.Type) -> @lifetime(copy 1, borrow 2)  @owned BufferView {
-  @lifetime(copy a, borrow b)
+  @_lifetime(copy a, borrow b)
   init(_ ptr: UnsafeRawBufferPointer, _ a: consuming Wrapper, _ b: borrowing Array<Int>) {
     self.ptr = ptr
   }
@@ -69,7 +45,7 @@ struct BufferView : ~Escapable {
 
 struct MutableBufferView : ~Escapable, ~Copyable {
   let ptr: UnsafeMutableRawBufferPointer
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(_ ptr: UnsafeMutableRawBufferPointer) {
     self.ptr = ptr
   }
@@ -87,29 +63,30 @@ func testBasic() {
 }
 
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers6deriveyAA10BufferViewVADF : $@convention(thin) (@guaranteed BufferView) -> @lifetime(borrow 0)  @owned BufferView {
-@lifetime(borrow x)
+@_lifetime(borrow x)
 func derive(_ x: borrowing BufferView) -> BufferView {
   return BufferView(independent: x.ptr)
 }
 
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers16consumeAndCreateyAA10BufferViewVADnF : $@convention(thin) (@owned BufferView) -> @lifetime(copy 0)  @owned BufferView {
-@lifetime(copy x)
+@_lifetime(copy x)
 func consumeAndCreate(_ x: consuming BufferView) -> BufferView {
   let bv = BufferView(independent: x.ptr)
   return _overrideLifetime(bv, copying: x)
 }
 
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers17deriveThisOrThat1yAA10BufferViewVAD_ADtF : $@convention(thin) (@guaranteed BufferView, @guaranteed BufferView) -> @lifetime(copy 1, borrow 0)  @owned BufferView {
-@lifetime(borrow this, copy that)
+@_lifetime(borrow this, copy that)
 func deriveThisOrThat1(_ this: borrowing BufferView, _ that: borrowing BufferView) -> BufferView {
   if (Int.random(in: 1..<100) == 0) {
     return BufferView(independent: this.ptr)
   }
-  return BufferView(independent: that.ptr)
+  let newThat = BufferView(independent: that.ptr)
+  return _overrideLifetime(newThat, copying: that)
 }
 
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers17deriveThisOrThat2yAA10BufferViewVAD_ADntF : $@convention(thin) (@guaranteed BufferView, @owned BufferView) -> @lifetime(copy 1, borrow 0)  @owned BufferView {
-@lifetime(borrow this, copy that)
+@_lifetime(borrow this, copy that)
 func deriveThisOrThat2(_ this: borrowing BufferView, _ that: consuming BufferView) -> BufferView {
   if (Int.random(in: 1..<100) == 0) {
     return BufferView(independent: this.ptr)
@@ -122,18 +99,18 @@ func use(_ x: borrowing BufferView) {}
 
 struct Wrapper : ~Escapable {
   let view: BufferView
-  @lifetime(copy view)
+  @_lifetime(copy view)
   init(_ view: consuming BufferView) {
     self.view = view
   }
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers7WrapperV8getView1AA10BufferViewVyF : $@convention(method) (@guaranteed Wrapper) -> @lifetime(borrow 0)  @owned BufferView {
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func getView1() -> BufferView {
     return view
   }
 
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers7WrapperV8getView2AA10BufferViewVyF : $@convention(method) (@owned Wrapper) -> @lifetime(copy 0)  @owned BufferView {
-  @lifetime(copy self)
+  @_lifetime(copy self)
   consuming func getView2() -> BufferView {
     return view
   }
@@ -141,21 +118,21 @@ struct Wrapper : ~Escapable {
 
 struct Container : ~Escapable {
  let ptr: UnsafeRawBufferPointer
- @lifetime(borrow ptr)
+ @_lifetime(borrow ptr)
  init(_ ptr: UnsafeRawBufferPointer) {
    self.ptr = ptr
  }
 }
 
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers16getConsumingViewyAA06BufferG0VAA9ContainerVnF : $@convention(thin) (@owned Container) -> @lifetime(copy 0)  @owned BufferView {
-@lifetime(copy x)
+@_lifetime(copy x)
 func getConsumingView(_ x: consuming Container) -> BufferView {
   let bv = BufferView(independent: x.ptr)
   return _overrideLifetime(bv, copying: x)
 }
 
 // CHECK-LABEL: sil hidden @$s39explicit_lifetime_dependence_specifiers16getBorrowingViewyAA06BufferG0VAA9ContainerVF : $@convention(thin) (@guaranteed Container) -> @lifetime(borrow 0)  @owned BufferView {
-@lifetime(borrow x)
+@_lifetime(borrow x)
 func getBorrowingView(_ x: borrowing Container) -> BufferView {
   return BufferView(independent: x.ptr)
 }
diff --git a/test/SIL/implicit_lifetime_dependence.swift b/test/SIL/implicit_lifetime_dependence.swift
index 181235c3b7daa..9774c26df922e 100644
--- a/test/SIL/implicit_lifetime_dependence.swift
+++ b/test/SIL/implicit_lifetime_dependence.swift
@@ -1,61 +1,37 @@
 // RUN: %target-swift-frontend %s \
 // RUN: -emit-sil  -target %target-swift-5.1-abi-triple \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: | %FileCheck %s
 
-// REQUIRES: swift_feature_LifetimeDependence
-
-@_unsafeNonescapableResult
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, borrowing source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
-
-@_unsafeNonescapableResult
-@lifetime(copy source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, copying source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
+// REQUIRES: swift_feature_Lifetimes
 
 struct BufferView : ~Escapable {
   let ptr: UnsafeRawBufferPointer
   let c: Int
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(_ ptr: UnsafeRawBufferPointer, _ c: Int) {
     self.ptr = ptr
     self.c = c
   }
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(independent ptr: UnsafeRawBufferPointer, _ c: Int) {
     self.ptr = ptr
     self.c = c
   }
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence10BufferViewVyA2ChcfC : $@convention(method) (@guaranteed BufferView, @thin BufferView.Type) -> @lifetime(copy 0) @owned BufferView {
-  @lifetime(copy otherBV)
+  @_lifetime(copy otherBV)
   init(_ otherBV: borrowing BufferView) {
     self.ptr = otherBV.ptr
     self.c = otherBV.c
   }
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence10BufferViewVyA2CcfC : $@convention(method) (@owned BufferView, @thin BufferView.Type) -> @lifetime(copy 0) @owned BufferView {
-  @lifetime(copy otherBV)
+  @_lifetime(copy otherBV)
   init(_ otherBV: consuming BufferView) {
     self.ptr = otherBV.ptr
     self.c = otherBV.c
   }
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence10BufferViewVyACSW_SaySiGhtcfC : $@convention(method) (UnsafeRawBufferPointer, @guaranteed Array<Int>, @thin BufferView.Type) -> @lifetime(borrow 0) @owned BufferView {
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(_ ptr: UnsafeRawBufferPointer, _ a: borrowing Array<Int>) {
     self.ptr = ptr
     self.c = a.count
@@ -65,7 +41,7 @@ struct BufferView : ~Escapable {
 struct MutableBufferView : ~Escapable, ~Copyable {
   let ptr: UnsafeMutableRawBufferPointer
   let c: Int
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(_ ptr: UnsafeMutableRawBufferPointer, _ c: Int) {
     self.ptr = ptr
     self.c = c
@@ -83,18 +59,20 @@ func testBasic() {
 }
 
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence6deriveyAA10BufferViewVADF : $@convention(thin) (@guaranteed BufferView) -> @lifetime(copy 0)  @owned BufferView {
-@lifetime(copy x)
+@_lifetime(copy x)
 func derive(_ x: borrowing BufferView) -> BufferView {
-  return BufferView(x.ptr, x.c)
+  let newBV = BufferView(x.ptr, x.c)
+  return _overrideLifetime(newBV, copying: x)
 }
 
-@lifetime(copy x)
+@_lifetime(copy x)
 func derive(_ unused: Int, _ x: borrowing BufferView) -> BufferView {
-  return BufferView(independent: x.ptr, x.c)
+  let newBV = BufferView(independent: x.ptr, x.c)
+  return _overrideLifetime(newBV, copying: x)
 }
 
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence16consumeAndCreateyAA10BufferViewVADnF : $@convention(thin) (@owned BufferView) -> @lifetime(copy 0)  @owned BufferView {
-@lifetime(copy x)
+@_lifetime(copy x)
 func consumeAndCreate(_ x: consuming BufferView) -> BufferView {
   let bv = BufferView(independent: x.ptr, x.c)
   return _overrideLifetime(bv, copying: x)
@@ -106,29 +84,29 @@ struct Wrapper : ~Escapable {
   var _view: BufferView
   var view: BufferView {
 // CHECK: sil hidden @$s28implicit_lifetime_dependence7WrapperV4viewAA10BufferViewVvr : $@yield_once @convention(method) (@guaranteed Wrapper) -> @lifetime(copy 0) @yields @guaranteed BufferView {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield _view
     }
-// CHECK: sil hidden @$s28implicit_lifetime_dependence7WrapperV4viewAA10BufferViewVvM : $@yield_once @convention(method) (@inout Wrapper) -> @lifetime(borrow 0) @yields @inout BufferView {
-    @lifetime(borrow self)
+// CHECK: sil hidden @$s28implicit_lifetime_dependence7WrapperV4viewAA10BufferViewVvM : $@yield_once @convention(method) (@lifetime(copy 0) @inout Wrapper) -> @lifetime(borrow 0) @yields @inout BufferView {
+    @_lifetime(&self)
     _modify {
       yield &_view
     }
   }
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence7WrapperVyAcA10BufferViewVcfC : $@convention(method) (@owned BufferView, @thin Wrapper.Type) -> @lifetime(copy 0) @owned Wrapper {
-  @lifetime(copy view)
+  @_lifetime(copy view)
   init(_ view: consuming BufferView) {
     self._view = view
   }
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence7WrapperV8getView1AA10BufferViewVyKF : $@convention(method) (@guaranteed Wrapper) -> @lifetime(copy 0)  (@owned BufferView, @error any Error) {
-  @lifetime(copy self)
+  @_lifetime(copy self)
   borrowing func getView1() throws -> BufferView {
     return _view
   }
 
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence7WrapperV8getView2AA10BufferViewVyYaKF : $@convention(method) @async (@owned Wrapper) -> @lifetime(copy 0)  (@owned BufferView, @error any Error) {
-  @lifetime(copy self)
+  @_lifetime(copy self)
   consuming func getView2() async throws -> BufferView {
     return _view
   }
@@ -170,7 +148,7 @@ struct GenericBufferView<Element> : ~Escapable {
   let count: Int
 
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence17GenericBufferViewV11baseAddress5countACyxGSV_SitcfC : $@convention(method) <Element> (UnsafeRawPointer, Int, @thin GenericBufferView<Element>.Type) -> @lifetime(borrow 0) @owned GenericBufferView<Element> {
-  @lifetime(borrow baseAddress)
+  @_lifetime(borrow baseAddress)
   init<Storage>(baseAddress: Pointer,
                 count: Int,
                 dependsOn: borrowing Storage) {
@@ -178,7 +156,7 @@ struct GenericBufferView<Element> : ~Escapable {
                                       count: count)
   }
   // unsafe private API
-  @lifetime(borrow baseAddress)
+  @_lifetime(borrow baseAddress)
   init(baseAddress: Pointer, count: Int) {
     precondition(count >= 0, "Count must not be negative")
     self.baseAddress = baseAddress
@@ -196,7 +174,7 @@ struct GenericBufferView<Element> : ~Escapable {
   }
 // CHECK: sil hidden @$s28implicit_lifetime_dependence17GenericBufferViewVyACyxGAA9FakeRangeVySVGcig : $@convention(method) <Element> (FakeRange<UnsafeRawPointer>, @guaranteed GenericBufferView<Element>) -> @lifetime(copy 1) @owned GenericBufferView<Element> {
   subscript(bounds: FakeRange<Pointer>) -> Self {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     get {
       let pointer = UnsafeRawPointer(bounds.lowerBound)
       let result = GenericBufferView(
@@ -210,9 +188,11 @@ struct GenericBufferView<Element> : ~Escapable {
 }
 
 // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence23tupleLifetimeDependenceyAA10BufferViewV_ADtADF : $@convention(thin) (@guaranteed BufferView) -> @lifetime(copy 0)  (@owned BufferView, @owned BufferView) {
-@lifetime(copy x)
+@_lifetime(copy x)
 func tupleLifetimeDependence(_ x: borrowing BufferView) -> (BufferView, BufferView) {
-  return (BufferView(x.ptr, x.c), BufferView(x.ptr, x.c))
+  let newX1 = BufferView(x.ptr, x.c)
+  let newX2 = BufferView(x.ptr, x.c)
+  return (_overrideLifetime(newX1, copying: x), _overrideLifetime(newX2, copying: x))
 }
 
 public struct OuterNE: ~Escapable {
@@ -224,26 +204,26 @@ public struct OuterNE: ~Escapable {
 
   // Explicit setter with an infered dependence on 'newValue'.
   public var inner2: InnerNE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     get { inner1 }
-    @lifetime(self: copy newValue)
+    @_lifetime(self: copy newValue)
     set { inner1 = newValue }
   }
 
   public struct InnerNE: ~Escapable {
-    @lifetime(copy owner)
+    @_lifetime(copy owner)
     init<Owner: ~Escapable & ~Copyable>(
       owner: borrowing Owner
     ) {}
   }
 
-  @lifetime(copy owner)
+  @_lifetime(copy owner)
   init<Owner: ~Copyable & ~Escapable>(owner: borrowing Owner) {
     self.inner1 = InnerNE(owner: owner)
   }
 
   // CHECK-LABEL: sil hidden @$s28implicit_lifetime_dependence7OuterNEV8setInner5valueyAC0gE0V_tF : $@convention(method) (@guaranteed OuterNE.InnerNE, @lifetime(copy 0) @inout OuterNE) -> () {
-  @lifetime(self: copy value)
+  @_lifetime(self: copy value)
   mutating func setInner(value: InnerNE) {
     self.inner1 = value
   }
diff --git a/test/SIL/lifetime_dependence_generics.swift b/test/SIL/lifetime_dependence_generics.swift
index 501a8a58015ea..521498c360143 100644
--- a/test/SIL/lifetime_dependence_generics.swift
+++ b/test/SIL/lifetime_dependence_generics.swift
@@ -1,32 +1,32 @@
 // RUN: %target-swift-frontend %s -emit-sil \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-feature SuppressedAssociatedTypes \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_SuppressedAssociatedTypes
 
 protocol P {
   associatedtype E: ~Escapable
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func getE() -> E
 }
 
 extension P {
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func getDefault() -> E {
     return getE()
   }
 }
 
 public struct View: ~Escapable {
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init() { }
 }
 
 public struct PView: P {
-  @lifetime(immortal)
+  @_lifetime(immortal)
   borrowing func getE() -> View { return View() }
 }
 
diff --git a/test/SIL/lifetime_dependence_param_position_test.swift b/test/SIL/lifetime_dependence_param_position_test.swift
index 6988bfbd3a89b..5423cf9125f5a 100644
--- a/test/SIL/lifetime_dependence_param_position_test.swift
+++ b/test/SIL/lifetime_dependence_param_position_test.swift
@@ -1,14 +1,14 @@
 // RUN: %target-swift-frontend %s -emit-silgen \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 
 public struct Span<Element> : ~Escapable {
   private var baseAddress: UnsafeRawPointer
   public let count: Int
-  @lifetime(copy owner)
+  @_lifetime(copy owner)
   public init<Owner: ~Copyable & ~Escapable>(
       baseAddress: UnsafeRawPointer,
       count: Int,
@@ -30,7 +30,7 @@ extension ContiguousArray {
 }
 
 // CHECK-LABEL: sil hidden @$s39lifetime_dependence_param_position_test11mayReassign4span2toyAA4SpanVySiGz_s15ContiguousArrayVySiGtF : $@convention(thin) (_lifetime(_borrow 1) @inout Span<Int>, @guaranteed ContiguousArray<Int>) -> () {
-@lifetime(span: borrow to)
+@_lifetime(span: borrow to)
 func mayReassign(span: inout Span<Int>, to: ContiguousArray<Int>) {
   span = to.span
 }
diff --git a/test/SIL/lifetime_dependence_span_lifetime_attr.swift b/test/SIL/lifetime_dependence_span_lifetime_attr.swift
index 4d478b19b2523..e18e9c66463f5 100644
--- a/test/SIL/lifetime_dependence_span_lifetime_attr.swift
+++ b/test/SIL/lifetime_dependence_span_lifetime_attr.swift
@@ -1,33 +1,9 @@
 // RUN: %target-swift-frontend %s -emit-sil \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
-
-@_unsafeNonescapableResult
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, borrowing source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
-
-@_unsafeNonescapableResult
-@lifetime(copy source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, copying source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
+// REQUIRES: swift_feature_Lifetimes
 
 // TODO: Use real Range
 public struct FakeRange<Bound> {
@@ -83,7 +59,7 @@ public struct Span<Element> : ~Escapable {
   public let count: Int
   private var baseAddress: UnsafeRawPointer { start._rawValue }
 // CHECK-LABEL: sil @$s025lifetime_dependence_span_A5_attr4SpanV11baseAddress5count9dependsOnACyxGSV_Siqd__htcRi_d__Ri0_d__lufC : $@convention(method) <Element><Owner where Owner : ~Copyable, Owner : ~Escapable> (UnsafeRawPointer, Int, @in_guaranteed Owner, @thin Span<Element>.Type) -> @lifetime(copy 2) @owned Span<Element> {
-  @lifetime(copy owner)
+  @_lifetime(copy owner)
   public init<Owner: ~Copyable & ~Escapable>(
       baseAddress: UnsafeRawPointer,
       count: Int,
@@ -94,7 +70,7 @@ public struct Span<Element> : ~Escapable {
       )
   }
 // CHECK-LABEL: sil hidden @$s025lifetime_dependence_span_A5_attr4SpanV5start5count9dependsOnACyxGAA0E5IndexVyxG_Siqd__htcRi_d__Ri0_d__lufC : $@convention(method) <Element><Owner where Owner : ~Copyable, Owner : ~Escapable> (SpanIndex<Element>, Int, @in_guaranteed Owner, @thin Span<Element>.Type) -> @lifetime(copy 2) @owned Span<Element> {
-  @lifetime(copy owner)
+  @_lifetime(copy owner)
   init<Owner: ~Copyable & ~Escapable>(
     start index: SpanIndex<Element>,
     count: Int,
@@ -150,7 +126,7 @@ extension Span {
  
 // CHECK-LABEL: sil @$s025lifetime_dependence_span_A5_attr4SpanVyACyxGAA9FakeRangeVyAA0E5IndexVyxGGcig : $@convention(method) <Element> (FakeRange<SpanIndex<Element>>, @guaranteed Span<Element>) -> @lifetime(copy 1) @owned Span<Element> {
   public subscript(bounds: FakeRange<SpanIndex<Element>>) -> Self {
-  @lifetime(copy self)
+  @_lifetime(copy self)
     get {
       let span = Span(
         start: bounds.lowerBound,
@@ -161,7 +137,7 @@ extension Span {
   }
 
 // CHECK-LABEL: sil @$s025lifetime_dependence_span_A5_attr4SpanV6prefix4upToACyxGAA0E5IndexVyxG_tF : $@convention(method) <Element> (SpanIndex<Element>, @guaranteed Span<Element>) -> @lifetime(copy 1) @owned Span<Element> {
-  @lifetime(copy self)
+  @_lifetime(copy self)
   borrowing public func prefix(upTo index: SpanIndex<Element>) -> Self {
     index == startIndex
     ? Self(start: start, count: 0, dependsOn: copy self)
@@ -169,14 +145,14 @@ extension Span {
   }
 
 // CHECK-LABEL: sil @$s025lifetime_dependence_span_A5_attr4SpanV6prefix7throughACyxGAA0E5IndexVyxG_tF : $@convention(method) <Element> (SpanIndex<Element>, @guaranteed Span<Element>) -> @lifetime(copy 1) @owned Span<Element> {
-  @lifetime(copy self)
+  @_lifetime(copy self)
   borrowing public func prefix(through index: Index) -> Self {
     let nc = distance(from: startIndex, to: index) &+ 1
     return Self(start: start, count: nc, dependsOn: copy self)
   }
 
 // CHECK-LABEL: sil @$s025lifetime_dependence_span_A5_attr4SpanV6prefixyACyxGSiF : $@convention(method) <Element> (Int, @owned Span<Element>) -> @lifetime(copy 1) @owned Span<Element> {
-  @lifetime(copy self)
+  @_lifetime(copy self)
   consuming public func prefix(_ maxLength: Int) -> Self {
     precondition(maxLength >= 0, "Can't have a prefix of negative length.")
     let nc = maxLength < count ? maxLength : count
@@ -186,7 +162,7 @@ extension Span {
 
 extension ContiguousArray {
   public var view: Span<Element> {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     borrowing _read {
       yield Span(
         baseAddress: _baseAddressIfContiguous!, count: count, dependsOn: self
diff --git a/test/SIL/manual_ownership.swift b/test/SIL/manual_ownership.swift
new file mode 100644
index 0000000000000..e4180306bbd14
--- /dev/null
+++ b/test/SIL/manual_ownership.swift
@@ -0,0 +1,479 @@
+// RUN: %target-swift-frontend %s -emit-sil -verify \
+// RUN:   -enable-experimental-feature ManualOwnership
+
+// REQUIRES: swift_feature_ManualOwnership
+
+// MARK: types
+
+public class Whatever {
+  var a = Pair(x: 0, y: 0)
+}
+
+public struct Pair {
+  var x: Int
+  var y: Int
+
+  @_manualOwnership
+  consuming func midpoint(_ other: borrowing Pair) -> Pair {
+    return Pair(x: (x + other.x) / 2, y: (y + other.y) / 2)
+  }
+}
+
+public class Triangle {
+  var a = Pair(x: 0, y: 0)
+  var b = Pair(x: 0, y: 1)
+  var c = Pair(x: 1, y: 1)
+
+  var nontrivial = Whatever()
+
+  @_manualOwnership
+  consuming func consuming() {}
+
+  @_manualOwnership
+  borrowing func borrowing() {}
+}
+
+// MARK: utilities
+
+func eat(_ t: consuming Triangle) {}
+func use(_ t: borrowing Triangle) {}
+
+func consume_generic<T>(_ t: consuming T) {}
+func borrow_generic<T>(_ t: borrowing T) {}
+
+/// MARK: return statements
+
+@_manualOwnership
+public func basic_return1() -> Triangle {
+  let x = Triangle()
+  return x
+}
+
+@_manualOwnership
+public func basic_return2(t: Triangle) -> Triangle {
+  return t // expected-error {{independent copy of 't' is required here; write 'copy' to acknowledge or 'consume' to elide}}
+}
+@_manualOwnership
+public func basic_return2_fixed(t: Triangle) -> Triangle {
+  return copy t
+}
+
+@_manualOwnership
+public func basic_return3() -> Triangle {
+  return Triangle()
+}
+
+@_manualOwnership
+func return_borrowed(_ t: borrowing Triangle) -> Triangle {
+  return t // expected-error {{independent copy of 't' is required here; write 'copy' to acknowledge or 'consume' to elide}}
+}
+@_manualOwnership
+func return_borrowed_fixed(_ t: borrowing Triangle) -> Triangle {
+  return copy t
+}
+
+// FIXME: there's no workaround to this; it acts like a var so it's the same class of problem (rdar://161359163)
+@_manualOwnership
+func return_consumingParam(_ t: consuming Triangle) -> Triangle {
+  return t // expected-error {{independent copy of 't' is required here; write 'copy' to acknowledge or 'consume' to elide}}
+}
+@_manualOwnership
+func return_consumingParam_no_workaround(_ t: consuming Triangle) -> Triangle {
+  return copy t
+}
+
+@_manualOwnership
+func return_owned(_ t: __owned Triangle) -> Triangle {
+  return t
+}
+
+@_manualOwnership
+func reassign_with_lets() -> Triangle {
+  let x = Triangle()
+  let y = x
+  let z = y
+  return z
+}
+
+@_manualOwnership
+func renamed_return(_ cond: Bool, _ a: Triangle) -> Triangle {
+  let b = a
+  let c = b
+  // FIXME: we say 'c' instead of 'b', because of the propagation. (rdar://161360537)
+  if cond { return b } // expected-error {{independent copy of 'c' is required}}
+  return c // expected-error {{independent copy of 'c' is required}}
+}
+
+@_manualOwnership
+func renamed_return_fix1(_ cond: Bool, _ a: Triangle) -> Triangle {
+  let b = copy a
+  let c = copy b  // FIXME: not needed! Is explicit_copy_value is blocking propagation? (rdar://161359163)
+  if cond { return b }
+  return c
+}
+
+// FIXME: this crashes CopyPropagation! (rdar://161360764)
+//@_manualOwnership
+//func renamed_return_fix2(_ cond: Bool, _ a: Triangle) -> Triangle {
+//  let b = a
+//  let c = b
+//  if cond { return copy b }
+//  return copy c
+//}
+
+/// MARK: method calls
+
+@_manualOwnership
+func basic_methods_borrowing(_ t1: Triangle) {
+  let t2 = Triangle()
+  t1.borrowing()
+  t2.borrowing()
+}
+
+@_manualOwnership
+func basic_methods_consuming(_ t1: Triangle) {
+  let t2 = Triangle()
+  t1.consuming() // expected-error {{independent copy of 't1' is required}}
+  t2.consuming()
+}
+@_manualOwnership
+func basic_methods_consuming_fixed(_ t1: Triangle) {
+  let t2 = Triangle()
+
+  (copy t1).consuming()
+  (copy t2).consuming()  // FIXME: why is this not propagated?
+}
+
+open class OpenClass {
+  open func classMethod() {}
+}
+@_manualOwnership
+func callOpenMethod(_ c: OpenClass) {
+  return c.classMethod()
+}
+
+@_manualOwnership
+@discardableResult
+func consumingFunc(_ t0: consuming Triangle) -> Bool { return false }
+
+@_manualOwnership
+func plainFunc(_ t0: Triangle) {}
+
+@_manualOwnership
+func basic_function_call(_ t1: Triangle) {
+  consumingFunc(t1) // expected-error {{independent copy of 't1' is required}}
+  consumingFunc(copy t1)
+  plainFunc(t1)
+}
+
+/// MARK: control-flow
+
+@_manualOwnership
+func check_vars(_ t: Triangle, _ b: Bool) -> Triangle {
+  var x = Triangle()
+  if b { x = t } // expected-error {{independent copy of 't' is required}}
+  return x // expected-error {{independent copy of 'x' is required}}
+}
+@_manualOwnership
+func check_vars_fixed(_ t: Triangle, _ b: Bool) -> Triangle {
+  var x = Triangle()
+  if b { x = copy t }
+  return copy x
+}
+
+// FIXME: var's still have some issues
+// (1) MandatoryRedundantLoadElimination introduces a 'copy_value' in place of a 'load [copy]' (rdar://161359163)
+
+@_manualOwnership
+func reassignments_0() -> Triangle {
+  var t3 = Triangle()
+  t3 = Triangle()
+  return t3 // expected-error {{independent copy of 't3' is required}}
+}
+@_manualOwnership
+func reassignments_0_fixed_1() -> Triangle {
+  var t3 = Triangle()
+  t3 = Triangle()
+  return copy t3
+}
+@_manualOwnership
+func reassignments_0_fixed_2() -> Triangle {
+  var t3 = Triangle()
+  t3 = Triangle()
+  return consume t3
+}
+
+@_manualOwnership
+func reassignments_1() {
+  var t3 = Triangle()
+  t3 = Triangle()
+  t3.borrowing() // expected-error {{accessing 't3' may produce a copy; write 'copy' to acknowledge or 'consume' to elide}}
+}
+@_manualOwnership
+func reassignments_1_fixed_1() {
+  var t3 = Triangle()
+  t3 = Triangle()
+  (copy t3).borrowing()
+}
+@_manualOwnership
+func reassignments_1_fixed_2() {
+  var t3 = Triangle()
+  t3 = Triangle()
+  (consume t3).borrowing()
+}
+
+@_manualOwnership
+public func basic_loop_trivial_values(_ t: Triangle, _ xs: [Triangle]) {
+  var p: Pair = t.a
+  for x in xs { // expected-error {{independent copy of 'xs' is required}}
+    p = p.midpoint(x.a)
+  }
+  t.a = p
+}
+@_manualOwnership
+public func basic_loop_trivial_values_fixed(_ t: Triangle, _ xs: [Triangle]) {
+  var p: Pair = t.a
+  for x in copy xs {
+    p = p.midpoint(x.a)
+  }
+  t.a = p
+}
+
+// FIXME: the only reason for so many copies below is because
+// `Triangle.nontrivial` only exposes get/set rather than read/modify by default
+//
+// There's complexity in auto-generating a read accessor for classes, but if it's provided
+// we could then allow someone to elide the copy with a `borrow x` expression.
+
+@_manualOwnership
+public func basic_loop_nontrivial_values(_ t: Triangle, _ xs: [Triangle]) {
+  var p: Pair = t.nontrivial.a // expected-error {{accessing 't.nontrivial' may produce a copy}}
+  for x in xs { // expected-error {{independent copy of 'xs' is required}}
+    p = p.midpoint(x.nontrivial.a) // expected-error {{accessing 'x.nontrivial' may produce a copy}}
+  }
+  t.nontrivial.a = p // expected-error {{accessing 't.nontrivial' may produce a copy}}
+}
+
+@_manualOwnership
+public func basic_loop_nontrivial_values_fixed(_ t: Triangle, _ xs: [Triangle]) {
+  var p: Pair = (copy t.nontrivial).a
+  for x in copy xs {
+    p = p.midpoint((copy x.nontrivial).a)
+  }
+  (copy t.nontrivial).a = p
+}
+
+@_manualOwnership
+public func basic_loop_nontrivial_values_reduced_copies(_ t: Triangle, _ xs: [Triangle]) {
+  // FIXME: confusing variable names are chosen (rdar://161360537)
+  let nt = t.nontrivial // expected-error {{accessing 'nt' may produce a copy}}
+  var p: Pair = nt.a
+  for x in copy xs {
+    let xnt = x.nontrivial // expected-error {{accessing 'xnt' may produce a copy}}
+    p = p.midpoint(xnt.a)
+  }
+  nt.a = p
+}
+@_manualOwnership
+public func basic_loop_nontrivial_values_reduced_copies_fixed(_ t: Triangle, _ xs: [Triangle]) {
+  let nt = copy t.nontrivial
+  var p: Pair = nt.a
+  for x in copy xs {
+    let xnt = copy x.nontrivial
+    p = p.midpoint(xnt.a)
+  }
+  nt.a = p
+}
+
+
+/// MARK: Globals
+let ref_result = [5, 13, 29]
+
+// FIXME: if we had a borrow operator, we could allow people to elide these simple copies that
+//   are present to avoid exclusivity issues. We'd need to start generating read coroutines.
+@_manualOwnership
+func access_global_1() -> Int {
+  return ref_result[2] // expected-error {{accessing 'ref_result' may produce a copy}}
+}
+@_manualOwnership
+func access_global_1_fixed() -> Int {
+return (copy ref_result)[2]
+}
+
+/// MARK: closures
+
+@_manualOwnership
+func closure_basic(_ t: Triangle) -> () -> Triangle {
+  return { // expected-error {{closure capture of 't' requires independent copy of it; write [t = copy t]}}
+    return t // expected-error {{independent copy of 't' is required}}
+  }
+}
+@_manualOwnership
+func closure_basic_almost_fixed_1(_ t: Triangle) -> () -> Triangle {
+  // FIXME: Closure capture lists need to support the short-hand [copy t] that makes the
+  //        closure capture parameter @owned, rather than @guaranteed. Only can work for Copyable types!
+  return { [x = copy t] in
+    return x // expected-error {{independent copy of 'x' is required}}
+  }
+}
+
+@_manualOwnership
+func closure_basic_almost_fixed_2(_ x: Triangle) -> () -> Triangle {
+  return { // expected-error {{closure capture of 'x' requires independent copy of it; write [x = copy x]}}
+    return copy x
+  }
+}
+
+@_manualOwnership
+func closure_basic_fixed(_ t: Triangle) -> () -> Triangle {
+  return { [x = copy t] in
+    return copy x
+  }
+}
+
+@_manualOwnership
+func closure_copies_in_body(_ t: Triangle) -> () -> Triangle {
+  return { [x = copy t] in
+    eat(x) // expected-error {{independent copy of 'x' is required}}
+    use(x)
+    eat(x) // expected-error {{independent copy of 'x' is required}}
+    return x // expected-error {{independent copy of 'x' is required}}
+    }
+}
+
+@_manualOwnership
+func closure_copies_in_body_noescape(_ t: Triangle) -> Triangle {
+  let f = { [x = copy t] in
+    eat(x)  // expected-error {{independent copy of 'x' is required}}
+    use(x)
+    eat(x) // expected-error {{independent copy of 'x' is required}}
+    return x // expected-error {{independent copy of 'x' is required}}
+  }
+  return f()
+}
+
+@_manualOwnership
+func simple_assert(_ f: @autoclosure () -> Bool) {
+  guard f() else { fatalError() }
+}
+@_manualOwnership
+func try_to_assert(_ n: Int, _ names: [String]) {
+  simple_assert(names.count == n)
+}
+
+@_manualOwnership
+func copy_in_autoclosure(_ t: Triangle) {
+  simple_assert(consumingFunc(t)) // expected-error {{independent copy of 't' is required}}
+}
+@_manualOwnership
+func copy_in_autoclosure_fixed(_ t: Triangle) {
+  simple_assert(consumingFunc(copy t))
+}
+
+@_manualOwnership
+func nested_closures(_ t: Triangle) -> () -> (() -> Triangle) {
+  return { // expected-error {{closure capture of 't' requires independent copy of it; write [t = copy t]}}
+    { eat(t) }() // expected-error {{independent copy of 't' is required}}
+    return { // expected-error {{closure capture of 't' requires independent copy of it; write [t = copy t]}}
+      simple_assert(consumingFunc(t)) // expected-error {{independent copy of 't' is required}}
+      return t // expected-error {{independent copy of 't' is required}}
+    }
+  }
+}
+@_manualOwnership
+func nested_closures_fixed(_ t: Triangle) -> () -> (() -> Triangle) {
+  return { [a = copy t] in
+    { eat(copy a) }()
+    return { [b = copy a] in
+      simple_assert(consumingFunc(copy b))
+      return copy b
+    }
+  }
+}
+
+/// MARK: generics
+
+@_manualOwnership
+func return_generic<T>(_ t: T) -> T {
+  return t // expected-error {{accessing 't' may produce a copy}}
+}
+@_manualOwnership
+func return_generic_fixed<T>(_ t: T) -> T {
+  return copy t
+}
+
+@_manualOwnership
+func reassign_with_lets<T>(_ t: T) -> T {
+  let x = t // expected-error {{accessing 't' may produce a copy}}
+  let y = x // expected-error {{accessing 'x' may produce a copy}}
+  let z = y // expected-error {{accessing 'y' may produce a copy}}
+  return copy z
+}
+
+// FIXME: copy propagation has no effect on address-only types, so this is quite verbose.
+@_manualOwnership
+func reassign_with_lets_fixed<T>(_ t: T) -> T {
+  let x = copy t
+  let y = copy x
+  let z = copy y
+  return copy z
+}
+
+@_manualOwnership
+func copy_generic<T>(_ t: T)  {
+  consume_generic(t) // expected-error {{accessing 't' may produce a copy}}
+  borrow_generic(t)
+  consume_generic(t) // expected-error {{accessing 't' may produce a copy}}
+}
+
+@_manualOwnership
+func copy_generic_fixed<T>(_ t: T)  {
+  consume_generic(copy t)
+  borrow_generic(t)
+  consume_generic(copy t)
+}
+
+@_manualOwnership
+func benchCaptureProp<S : Sequence>(
+  _ s: S, _ f: (S.Element, S.Element) -> S.Element) -> S.Element {
+
+  var it = s.makeIterator() // expected-error {{accessing 's' may produce a copy}}
+  let initial = it.next()!
+  return
+    IteratorSequence(it) // expected-error {{accessing 'it' may produce a copy}}
+           .reduce(initial, f)
+}
+@_manualOwnership
+func benchCaptureProp_fixed<S : Sequence>(
+  _ s: S, _ f: (S.Element, S.Element) -> S.Element) -> S.Element {
+
+  var it = (copy s).makeIterator()
+  let initial = it.next()!
+  return
+    IteratorSequence(copy it)
+           .reduce(initial, f)
+}
+
+extension FixedWidthInteger {
+    @_manualOwnership
+    func leftRotate(_ distance: Int) -> Self {
+        return (self << distance) | (self >> (Self.bitWidth - distance))
+    }
+
+    @_manualOwnership
+    mutating func rotatedLeft(_ distance: Int) {
+        self = (copy self).leftRotate(distance)
+    }
+}
+
+struct CollectionOf32BitLittleEndianIntegers<BaseCollection: Collection> where BaseCollection.Element == UInt8 {
+    var baseCollection: BaseCollection
+
+    @_manualOwnership
+    init(_ baseCollection: BaseCollection) {
+        precondition(baseCollection.count % 4 == 0)
+        self.baseCollection = baseCollection // expected-error {{accessing 'baseCollection' may produce a copy}}
+    } // expected-error {{accessing 'self' may produce a copy}}
+
+    // FIXME: the above initializer shouldn't have any diagnostics
+}
diff --git a/test/SIL/memory_lifetime.sil b/test/SIL/memory_lifetime.sil
index 76c02a3538db9..406d77ad8958e 100644
--- a/test/SIL/memory_lifetime.sil
+++ b/test/SIL/memory_lifetime.sil
@@ -864,3 +864,11 @@ bb0:
   %10 = tuple ()                                  
   return %10                                      
 } 
+
+sil [ossa] @storage_leaked_into_dead_ends : $@convention(thin) () -> () {
+  %t = apply undef() : $@convention(thin) () -> (@owned T)
+  %t_addr = alloc_stack $T
+  store %t to [init] %t_addr
+  dealloc_stack %t_addr
+  unreachable
+}
diff --git a/test/SIL/verifier_nofail.sil b/test/SIL/verifier_nofail.sil
index 27f337f7e4539..2559624ee52a3 100644
--- a/test/SIL/verifier_nofail.sil
+++ b/test/SIL/verifier_nofail.sil
@@ -23,3 +23,13 @@ bb0(%0 : $*P):
   %9999 = tuple()
   return %9999 : $()
 }
+
+
+class Klass {}
+
+sil [ossa] [_semantics "sil.verify_none"] @foo : $@convention(thin) (@guaranteed Klass) -> () {
+bb0(%0 : @guaranteed $Klass):
+  destroy_value %0
+  %t = tuple()
+  return %t
+}
diff --git a/test/SILGen/82368.swift b/test/SILGen/82368.swift
new file mode 100644
index 0000000000000..b274101ef2040
--- /dev/null
+++ b/test/SILGen/82368.swift
@@ -0,0 +1,11 @@
+// RUN: %target-swift-emit-silgen -disable-availability-checking -verify %s
+
+struct A {
+  static let a: InlineArray = [1]
+
+  static func foo() {
+    a.span.withUnsafeBufferPointer({ buffer in
+      print("\(buffer.baseAddress!)")
+    })
+  }
+}
diff --git a/test/SILGen/Inputs/AvailabilityDomains.h b/test/SILGen/Inputs/AvailabilityDomains.h
new file mode 100644
index 0000000000000..9806517df089d
--- /dev/null
+++ b/test/SILGen/Inputs/AvailabilityDomains.h
@@ -0,0 +1,28 @@
+#include <availability_domain.h>
+
+int dynamic_domain_pred();
+
+CLANG_ENABLED_AVAILABILITY_DOMAIN(EnabledDomain);
+CLANG_DISABLED_AVAILABILITY_DOMAIN(DisabledDomain);
+CLANG_DYNAMIC_AVAILABILITY_DOMAIN(DynamicDomain, dynamic_domain_pred);
+
+#define AVAIL 0
+#define UNAVAIL 1
+
+__attribute__((availability(domain:EnabledDomain, AVAIL)))
+void available_in_enabled_domain(void);
+
+__attribute__((availability(domain:EnabledDomain, UNAVAIL)))
+void unavailable_in_enabled_domain(void);
+
+__attribute__((availability(domain:DisabledDomain, AVAIL)))
+void available_in_disabled_domain(void);
+
+__attribute__((availability(domain:DisabledDomain, UNAVAIL)))
+void unavailable_in_disabled_domain(void);
+
+__attribute__((availability(domain:DynamicDomain, AVAIL)))
+void available_in_dynamic_domain(void);
+
+__attribute__((availability(domain:DynamicDomain, UNAVAIL)))
+void unavailable_in_dynamic_domain(void);
diff --git a/test/SILGen/Inputs/clang_records_addressable_for_dependencies.h b/test/SILGen/Inputs/clang_records_addressable_for_dependencies.h
new file mode 100644
index 0000000000000..6c4dd44320f38
--- /dev/null
+++ b/test/SILGen/Inputs/clang_records_addressable_for_dependencies.h
@@ -0,0 +1,2 @@
+struct CStruct { int x; int y; };
+union CUnion { int x; int y; };
diff --git a/test/SILGen/Inputs/module.modulemap b/test/SILGen/Inputs/module.modulemap
index 53cc761b69592..c7ffc93319ec6 100644
--- a/test/SILGen/Inputs/module.modulemap
+++ b/test/SILGen/Inputs/module.modulemap
@@ -1,3 +1,7 @@
 module PointerAuth {
-   header "ptrauth_field_fptr_import.h"
- }
+  header "ptrauth_field_fptr_import.h"
+}
+
+module Variadic {
+  header "variadic.h"
+}
diff --git a/test/SILGen/Inputs/opaque_result_type_retroactive_other.swift b/test/SILGen/Inputs/opaque_result_type_retroactive_other.swift
new file mode 100644
index 0000000000000..5faa511ea5a30
--- /dev/null
+++ b/test/SILGen/Inputs/opaque_result_type_retroactive_other.swift
@@ -0,0 +1,9 @@
+public struct G<T> {
+  public init(_: T) {}
+}
+
+public protocol P {
+  associatedtype A: P
+
+  func a() -> A
+}
diff --git a/test/SILGen/Inputs/opaque_result_type_slow_other.swift b/test/SILGen/Inputs/opaque_result_type_slow_other.swift
new file mode 100644
index 0000000000000..c5ec4ce6b4a9b
--- /dev/null
+++ b/test/SILGen/Inputs/opaque_result_type_slow_other.swift
@@ -0,0 +1,8 @@
+public protocol P {}
+public protocol Q {}
+
+public func wrap<T: P & Q>(_ t: T) -> some P & Q {
+  return t
+}
+
+
diff --git a/test/SILGen/Inputs/preconcurrency-bridged-return.h b/test/SILGen/Inputs/preconcurrency-bridged-return.h
new file mode 100644
index 0000000000000..12ed7cdebdb1b
--- /dev/null
+++ b/test/SILGen/Inputs/preconcurrency-bridged-return.h
@@ -0,0 +1,9 @@
+@import Foundation;
+
+#define NS_SWIFT_SENDABLE __attribute__((__swift_attr__("@Sendable")))
+
+@interface TestClass: NSObject
+
+- (_Nullable id NS_SWIFT_SENDABLE)foo;
+
+@end
diff --git a/test/SILGen/Inputs/protocol-static-reqt-objc-class-impl.h b/test/SILGen/Inputs/protocol-static-reqt-objc-class-impl.h
new file mode 100644
index 0000000000000..9f8932fb7fd25
--- /dev/null
+++ b/test/SILGen/Inputs/protocol-static-reqt-objc-class-impl.h
@@ -0,0 +1,7 @@
+@import Foundation;
+
+@interface C: NSObject
+
++(_Nonnull instancetype)foo;
+
+@end
diff --git a/test/SILGen/Inputs/variadic.h b/test/SILGen/Inputs/variadic.h
new file mode 100644
index 0000000000000..61d5f968b781d
--- /dev/null
+++ b/test/SILGen/Inputs/variadic.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#include <stdarg.h>
+
+#define u_vformatMessage swift_u_vformatMessage
+void u_vformatMessage(int i, va_list ap);
diff --git a/test/SILGen/addressable_capture_2.swift b/test/SILGen/addressable_capture_2.swift
new file mode 100644
index 0000000000000..36026f87ac9a8
--- /dev/null
+++ b/test/SILGen/addressable_capture_2.swift
@@ -0,0 +1,21 @@
+// RUN: %target-swift-emit-silgen -enable-experimental-feature AddressableParameters %s | %FileCheck %s
+// REQUIRES: swift_feature_AddressableParameters
+struct Foo {
+	var x, y, z: Int
+
+	init() { fatalError() }
+
+	@_addressableSelf
+	func foo() {}
+}
+
+func block(_: (Int) -> ()) {}
+
+func test() {
+	let x = Foo()
+	block { (_) in x.foo() }
+}
+// ensure the closure properly nests the store_borrow after the alloc_stack:
+// CHECK-LABEL: sil{{.*}} @${{.*}}4test{{.*}}U_ : $
+// CHECK: [[STACK:%.*]] = alloc_stack
+// CHECK-NEXT: store_borrow {{.*}} to [[STACK]]
diff --git a/test/SILGen/addressable_for_dependencies.swift b/test/SILGen/addressable_for_dependencies.swift
index bb3759e5fab33..9564d8f16c693 100644
--- a/test/SILGen/addressable_for_dependencies.swift
+++ b/test/SILGen/addressable_for_dependencies.swift
@@ -1,7 +1,7 @@
-// RUN: %target-swift-emit-silgen -enable-experimental-feature AddressableTypes -enable-experimental-feature LifetimeDependence %s | %FileCheck %s
+// RUN: %target-swift-emit-silgen -enable-experimental-feature AddressableTypes -enable-experimental-feature Lifetimes %s | %FileCheck %s
 
 // REQUIRES: swift_feature_AddressableTypes
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 @_addressableForDependencies
 struct Foo { var x: String }
@@ -11,26 +11,26 @@ struct Bar { var foo: Foo }
 struct Dep: ~Escapable {
     var x: Int = 0
 
-    @lifetime(immortal)
+    @_lifetime(immortal)
     init() { }
 }
 
 // CHECK-LABEL: sil {{.*}}@$s{{.*}}12dependencyOn3foo{{.*}} :
 // CHECK-SAME:    (@in_guaranteed Foo) -> 
-@lifetime(borrow foo)
+@_lifetime(borrow foo)
 func dependencyOn(foo: Foo) -> Dep {
     // CHECK-NOT: load_borrow
 }
 // CHECK-LABEL: sil {{.*}}@$s{{.*}}12dependencyOn3bar{{.*}} :
 // CHECK-SAME:    (@in_guaranteed Bar) -> 
-@lifetime(borrow bar)
+@_lifetime(borrow bar)
 func dependencyOn(bar: Bar) -> Dep {
     // CHECK-NOT: load_borrow
 }
 
 // CHECK-LABEL: sil {{.*}}@$s{{.*}}12dependencyOn3foo6butNot{{.*}} :
 // CHECK-SAME:    (@in_guaranteed Foo, @guaranteed Foo) -> 
-@lifetime(borrow foo)
+@_lifetime(borrow foo)
 func dependencyOn(foo: Foo, butNot _: Foo) -> Dep {
     // CHECK: bb0(%0 : $*Foo,
     // CHECK:   apply {{.*}}(%0)
@@ -39,7 +39,7 @@ func dependencyOn(foo: Foo, butNot _: Foo) -> Dep {
 
 // CHECK-LABEL: sil {{.*}}@$s{{.*}}12dependencyOn3bar6butNot{{.*}} :
 // CHECK-SAME:    (@in_guaranteed Bar, @guaranteed Bar) -> 
-@lifetime(borrow bar)
+@_lifetime(borrow bar)
 func dependencyOn(bar: Bar, butNot _: Bar) -> Dep {
     // CHECK: bb0(%0 : $*Bar,
     // CHECK:   apply {{.*}}(%0)
@@ -49,14 +49,14 @@ func dependencyOn(bar: Bar, butNot _: Bar) -> Dep {
 extension Foo {
     // CHECK-LABEL: sil {{.*}}@$s{{.*}}3FooV16dependencyOnSelf{{.*}} :
     // CHECK-SAME:    (@in_guaranteed Foo) -> 
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func dependencyOnSelf() -> Dep {
         // CHECK-NOT: load_borrow
     }
 
     // CHECK-LABEL: sil {{.*}}@$s{{.*}}3FooV16dependencyOnSelf6butNot{{.*}} :
     // CHECK-SAME:    (@guaranteed Foo, @in_guaranteed Foo) -> 
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func dependencyOnSelf(butNot _: Foo) -> Dep {
         // CHECK: bb0({{.*}}, %1 : $*Foo)
         // CHECK:   apply {{.*}}(%1)
@@ -65,7 +65,7 @@ extension Foo {
 
     // CHECK-LABEL: sil {{.*}}@$s{{.*}}3FooV19dependencyNotOnSelf{{.*}} :
     // CHECK-SAME:    (@in_guaranteed Foo, @guaranteed Foo) -> 
-    @lifetime(borrow foo)
+    @_lifetime(borrow foo)
     func dependencyNotOnSelf(butOn foo: Foo) -> Dep {
         // CHECK: bb0(%0 : $*Foo,
         // CHECK:   apply {{.*}}(%0)
@@ -76,13 +76,13 @@ extension Foo {
 extension Bar {
     // CHECK-LABEL: sil {{.*}}@$s{{.*}}3BarV16dependencyOnSelf{{.*}} :
     // CHECK-SAME:    (@in_guaranteed Bar) -> 
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func dependencyOnSelf() -> Dep {
     }
 
     // CHECK-LABEL: sil {{.*}}@$s{{.*}}3BarV16dependencyOnSelf6butNot{{.*}} :
     // CHECK-SAME:    (@guaranteed Bar, @in_guaranteed Bar) -> 
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func dependencyOnSelf(butNot _: Bar) -> Dep {
         // CHECK: bb0({{.*}}, %1 : $*Bar)
         // CHECK:   apply {{.*}}(%1)
@@ -91,7 +91,7 @@ extension Bar {
 
     // CHECK-LABEL: sil {{.*}}@$s{{.*}}3BarV19dependencyNotOnSelf{{.*}} :
     // CHECK-SAME:    (@in_guaranteed Bar, @guaranteed Bar) -> 
-    @lifetime(borrow bar)
+    @_lifetime(borrow bar)
     func dependencyNotOnSelf(butOn bar: Bar) -> Dep {
         // CHECK: bb0(%0 : $*Bar,
         // CHECK:   apply {{.*}}(%0)
@@ -104,5 +104,5 @@ extension Bar {
 
 // CHECK-LABEL: sil {{.*}}@$s28addressable_for_dependencies14defaulArgument1iAA3DepVSi_tF :
 // CHECK-SAME: $@convention(thin) (Int) -> @lifetime(borrow 0) @owned Dep {
-@lifetime(borrow i)
+@_lifetime(borrow i)
 func defaulArgument(i: Int = 0) -> Dep {}
diff --git a/test/SILGen/addressable_global.swift b/test/SILGen/addressable_global.swift
new file mode 100644
index 0000000000000..6022ee0f663eb
--- /dev/null
+++ b/test/SILGen/addressable_global.swift
@@ -0,0 +1,30 @@
+// RUN: %target-swift-emit-silgen -parse-as-library -disable-availability-checking %s | %FileCheck %s
+
+enum Color {
+    case R, G, B
+}
+
+let colors: InlineArray<_, Color> = [
+    .G, .G, .R, .G, .G, .B,
+    .G, .G, .B, .G, .G, .R,
+    .B, .R, .G, .R, .B, .G,
+    .G, .G, .B, .G, .G, .R,
+    .G, .G, .R, .G, .G, .B,
+    .R, .B, .G, .B, .R, .G,
+]
+
+// CHECK-LABEL: sil{{.*}} @$s{{.*}}4main
+func main() {
+    // CHECK: [[POINTER:%.*]] = apply {{.*}}() : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK: [[ADDRESS:%.*]] = pointer_to_address [[POINTER]]
+    // CHECK: [[GET_SPAN:%.*]] = function_ref @$s{{.*}}11InlineArray{{.*}}4span
+    // CHECK: apply [[GET_SPAN]]<{{.*}}>([[ADDRESS]])
+    let span = colors.span
+    for elem in [3, 9, 8] {
+        switch span[elem] {
+        case .R: print(0)
+        case .G: print(1)
+        case .B: print(2)
+        }
+    }
+}
diff --git a/test/SILGen/addressable_members.swift b/test/SILGen/addressable_members.swift
new file mode 100644
index 0000000000000..e518b0610e557
--- /dev/null
+++ b/test/SILGen/addressable_members.swift
@@ -0,0 +1,148 @@
+// RUN: %target-swift-emit-silgen -enable-experimental-feature AddressableParameters %s | %FileCheck %s
+
+// REQUIRES: swift_feature_AddressableParameters
+
+protocol Gen {
+    associatedtype Ass
+    associatedtype Ind
+}
+
+struct Foo: Gen {
+    typealias Ass = Bar
+    typealias Ind = Int
+
+    var bar: Bar
+
+    var barAddressor: Bar {
+        unsafeAddress { fatalError() }
+    }
+
+    var barSelfAddressor: Bar {
+        @_addressableSelf
+        unsafeAddress { fatalError() }
+    }
+
+    subscript(i: Int) -> Bar {
+        unsafeAddress { fatalError() }
+    }
+}
+struct Bar {
+    var bas: Bas
+}
+struct Bas {
+    var end: Int
+}
+
+extension Gen {
+    var genAddressor: Ass {
+        unsafeAddress { fatalError() }
+    }
+
+    var genSelfAddressor: Ass {
+        @_addressableSelf
+        unsafeAddress { fatalError() }
+    }
+
+    subscript(gen i: Ind) -> Ass {
+        unsafeAddress { fatalError() }
+    }
+    subscript(genSelf i: Ind) -> Ass {
+        @_addressableSelf
+        unsafeAddress { fatalError() }
+    }
+}
+
+
+func bas(_ bas: borrowing @_addressable Bas) { }
+
+func bar(_ bar: borrowing @_addressable Bar) { }
+
+// CHECK-LABEL: sil {{.*}} @${{.*}}19testAddressableBase
+func testAddressableBase(_ foo: borrowing @_addressable Foo, i: Int) {
+// CHECK: bb0(%0 : @noImplicitCopy $*Foo
+    // CHECK: [[WRAP_BASE:%.*]] = copyable_to_moveonlywrapper_addr %0
+    // CHECK: [[BASE:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[WRAP_BASE]]
+
+    // CHECK: [[BAR:%.*]] = struct_element_addr [[BASE]], #Foo.bar
+    // CHECK: [[UNWRAP_BAR:%.*]] = moveonlywrapper_to_copyable_addr [[BAR]]
+    // CHECK: apply {{.*}}([[UNWRAP_BAR]])
+    bar(foo.bar)
+
+    // CHECK: [[BAR:%.*]] = struct_element_addr [[BASE]], #Foo.bar
+    // CHECK: [[BAS:%.*]] = struct_element_addr [[BAR]], #Bar.bas
+    // CHECK: [[UNWRAP_BAS:%.*]] = moveonlywrapper_to_copyable_addr [[BAS]]
+    // CHECK: apply {{.*}}([[UNWRAP_BAS]])
+    bas(foo.bar.bas)
+
+    // non-addressable base:
+    // CHECK: [[ADDRESSOR:%.*]] = function_ref @{{.*}}12barAddressor{{.*}}lu :
+    // CHECK: [[ADDRESS:%.*]] = apply [[ADDRESSOR]](
+    // CHECK: [[ADDRESS_RAW:%.*]] = struct_extract [[ADDRESS]], #UnsafePointer._rawValue
+    // CHECK: [[ADDRESS_ADDR:%.*]] = pointer_to_address [[ADDRESS_RAW]]
+    // CHECK: [[ADDRESS_DEP:%.*]] = mark_dependence {{.*}} [[ADDRESS_ADDR]]
+    // CHECK: apply {{.*}}([[ADDRESS_DEP]])
+    bar(foo.barAddressor)
+
+    // addressable base:
+    // CHECK: [[ADDRESSOR:%.*]] = function_ref @{{.*}}16barSelfAddressor{{.*}}lu :
+    // CHECK: [[UNWRAP_FOO:%.*]] = moveonlywrapper_to_copyable_addr [[BASE]]
+    // CHECK: [[ADDRESS:%.*]] = apply [[ADDRESSOR]]([[UNWRAP_FOO]])
+    // CHECK: [[ADDRESS_RAW:%.*]] = struct_extract [[ADDRESS]], #UnsafePointer._rawValue
+    // CHECK: [[ADDRESS_ADDR:%.*]] = pointer_to_address [[ADDRESS_RAW]]
+    // CHECK: [[ADDRESS_DEP:%.*]] = mark_dependence {{.*}} [[ADDRESS_ADDR]]
+    // CHECK: apply {{.*}}([[ADDRESS_DEP]])
+    bar(foo.barSelfAddressor)
+
+    // non-addressable base:
+    // CHECK: [[ADDRESSOR:%.*]] = function_ref @$s19addressable_members3FooVyAA3BarVSicilu :
+    // CHECK: [[ADDRESS:%.*]] = apply [[ADDRESSOR]](
+    // CHECK: [[ADDRESS_RAW:%.*]] = struct_extract [[ADDRESS]], #UnsafePointer._rawValue
+    // CHECK: [[ADDRESS_ADDR:%.*]] = pointer_to_address [[ADDRESS_RAW]]
+    // CHECK: [[ADDRESS_DEP:%.*]] = mark_dependence {{.*}} [[ADDRESS_ADDR]]
+    // CHECK: apply {{.*}}([[ADDRESS_DEP]])
+    bar(foo[i])
+    // CHECK: [[ADDRESSOR:%.*]] = function_ref @$s19addressable_members3FooVyAA3BarVSicilu :
+    // CHECK: [[ADDRESS:%.*]] = apply [[ADDRESSOR]](
+    // CHECK: [[ADDRESS_RAW:%.*]] = struct_extract [[ADDRESS]], #UnsafePointer._rawValue
+    // CHECK: [[ADDRESS_ADDR:%.*]] = pointer_to_address [[ADDRESS_RAW]]
+    // CHECK: [[ADDRESS_DEP:%.*]] = mark_dependence {{.*}} [[ADDRESS_ADDR]]
+    // CHECK: [[BAS_ADDRESS:%.*]] = struct_element_addr [[ADDRESS_DEP]], #Bar.bas
+    // CHECK: apply {{.*}}([[BAS_ADDRESS]])
+    bas(foo[i].bas)
+
+    // Temporary materialization outlives addressor call, even if it's not
+    // expected to be addressable.
+    // CHECK: [[TEMP:%.*]] = alloc_stack $Foo
+    // CHECK: [[ADDRESS:%.*]] = apply {{.*}}<Foo>([[TEMP]])
+    // CHECK: [[ADDRESS_RAW:%.*]] = struct_extract [[ADDRESS]], #UnsafePointer._rawValue
+    // CHECK: [[ADDRESS_ADDR:%.*]] = pointer_to_address [[ADDRESS_RAW]]
+    // CHECK: mark_dependence [unresolved] [[ADDRESS_ADDR]] on [[TEMP]]
+    // CHECK: dealloc_stack [[TEMP]]
+    bar(foo.genAddressor)
+    bar(foo[gen: i])
+
+    bar(foo.genSelfAddressor)
+    bar(foo[genSelf: i])
+}
+
+func temporaryFoo() -> Foo { fatalError() }
+
+func testTemporaryBase(_ foo: borrowing @_addressable Foo, i: Int) {
+    bar(temporaryFoo().bar)
+    bas(temporaryFoo().bar.bas)
+
+    bar(temporaryFoo().barAddressor)
+
+    bar(temporaryFoo().barSelfAddressor)
+
+    bar(temporaryFoo()[i])
+    bas(temporaryFoo()[i].bas)
+
+    bar(temporaryFoo().genAddressor)
+    bar(temporaryFoo()[gen: i])
+}
+
+func testInoutBase(_ foo: inout Foo) {
+    bar(foo.bar)
+    bas(foo.bar.bas)
+}
diff --git a/test/SILGen/addressable_params.swift b/test/SILGen/addressable_params.swift
index 87dac961fd899..bb4a786c18793 100644
--- a/test/SILGen/addressable_params.swift
+++ b/test/SILGen/addressable_params.swift
@@ -46,3 +46,21 @@ struct Foo {
         }
     }
 }
+
+enum TestEnum {
+    case foo(String)
+    case bar(String)
+}
+
+func addressableParam(_: @_addressable String) -> Bool { true }
+
+func testAddressableSwitchBinding(e: TestEnum) -> Bool {
+    return switch e {
+    case .foo(let f) where addressableParam(f):
+        true
+    case .bar(let b):
+        addressableParam(b)
+    default:
+        false
+    }
+}
diff --git a/test/SILGen/addressable_representation.swift b/test/SILGen/addressable_representation.swift
index 199b5910babef..4809c339a9d60 100644
--- a/test/SILGen/addressable_representation.swift
+++ b/test/SILGen/addressable_representation.swift
@@ -1,6 +1,6 @@
-// RUN: %target-swift-emit-silgen -enable-experimental-feature LifetimeDependence -enable-experimental-feature BuiltinModule -enable-experimental-feature AddressableTypes -enable-experimental-feature AddressableParameters -module-name main %s -define-availability 'Span 0.1:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999' | %FileCheck %s
+// RUN: %target-swift-emit-silgen -enable-experimental-feature Lifetimes -enable-experimental-feature BuiltinModule -enable-experimental-feature AddressableTypes -enable-experimental-feature AddressableParameters -module-name main %s -define-availability 'Span 0.1:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999' | %FileCheck %s
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_BuiltinModule
 // REQUIRES: swift_feature_AddressableTypes
 // REQUIRES: swift_feature_AddressableParameters
@@ -215,13 +215,13 @@ struct CO1 {
     init(_ s: String) { self.s = s }
 
     var storage: Span<String> {
-        @lifetime(borrow self)
+        @_lifetime(borrow self)
         borrowing get {
             fatalError()
         }
     }
 
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func getStorage() -> Span<String> {
         fatalError()
     }
@@ -235,13 +235,13 @@ struct CO2<T> {
     init(_ s: T) { self.s = s }
 
     var storage: Span<T> {
-        @lifetime(borrow self)
+        @_lifetime(borrow self)
         borrowing get {
             fatalError()
         }
     }
 
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func getStorage() -> Span<T> {
         fatalError()
     }
diff --git a/test/SILGen/addressors.swift b/test/SILGen/addressors.swift
index 9e416feef8444..a9829aff4ee53 100644
--- a/test/SILGen/addressors.swift
+++ b/test/SILGen/addressors.swift
@@ -65,8 +65,7 @@ func test0() {
 // CHECK: [[T1:%.*]] = apply [[T0]]({{%.*}}, [[AVAL]])
 // CHECK: [[T2:%.*]] = struct_extract [[T1]] : $UnsafePointer<Int32>, #UnsafePointer._rawValue
 // CHECK: [[T3:%.*]] = pointer_to_address [[T2]] : $Builtin.RawPointer to [strict] $*Int32
-// CHECK: [[MD:%.*]] = mark_dependence [nonescaping] [[T3]] : $*Int32 on [[AVAL]] : $A
-// CHECK: [[ACCESS:%.*]] = begin_access [read] [unsafe] [[MD]] : $*Int32
+// CHECK: [[ACCESS:%.*]] = begin_access [read] [unsafe] [[T3]] : $*Int32
 // CHECK: [[Z:%.*]] = load [[ACCESS]] : $*Int32
   let z = a[10]
 
@@ -102,8 +101,7 @@ func test1() -> Int32 {
 // CHECK: [[PTR:%.*]] = apply [[ACCESSOR]]({{%.*}}, [[A]]) : $@convention(method) (Int32, A) -> UnsafePointer<Int32>
 // CHECK: [[T0:%.*]] = struct_extract [[PTR]] : $UnsafePointer<Int32>, #UnsafePointer._rawValue
 // CHECK: [[T1:%.*]] = pointer_to_address [[T0]] : $Builtin.RawPointer to [strict] $*Int32
-// CHECK: [[MD:%.*]] = mark_dependence [nonescaping] [[T1]] : $*Int32 on [[A]] : $A
-// CHECK: [[ACCESS:%.*]] = begin_access [read] [unsafe] [[MD]] : $*Int32
+// CHECK: [[ACCESS:%.*]] = begin_access [read] [unsafe] [[T1]] : $*Int32
 // CHECK: [[T2:%.*]] = load [[ACCESS]] : $*Int32
 // CHECK: return [[T2]] : $Int32
   return A()[0]
@@ -198,9 +196,8 @@ func test_carray(_ array: inout CArray<(Int32) -> Int32>) -> Int32 {
 // CHECK:   [[T2:%.*]] = apply [[T1]]<(Int32) -> Int32>({{%.*}}, [[T0]])
 // CHECK:   [[T3:%.*]] = struct_extract [[T2]] : $UnsafePointer<(Int32) -> Int32>, #UnsafePointer._rawValue
 // CHECK:   [[T4:%.*]] = pointer_to_address [[T3]] : $Builtin.RawPointer to [strict] $*@callee_guaranteed @substituted <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0) -> @out τ_0_1 for <Int32, Int32>
-// CHECK:   [[MD:%.*]] = mark_dependence [nonescaping] [[T4]] : $*@callee_guaranteed @substituted <τ_0_0, τ_0_1>
 // (@in_guaranteed τ_0_0) -> @out τ_0_1 for <Int32, Int32> on [[T0]] : $CArray<(Int32) -> Int32>
-// CHECK:   [[ACCESS:%.*]] = begin_access [read] [unsafe] [[MD]]
+// CHECK:   [[ACCESS:%.*]] = begin_access [read] [unsafe] [[T4]]
 // CHECK:   [[T5:%.*]] = load [[ACCESS]]
   return array[1](5)
 }
@@ -289,8 +286,7 @@ struct E {
 // CHECK:   [[T1:%.*]] = apply [[T0]]([[E]])
 // CHECK:   [[T2:%.*]] = struct_extract [[T1]]
 // CHECK:   [[T3:%.*]] = pointer_to_address [[T2]]
-// CHECK:   [[MD:%.*]] = mark_dependence [nonescaping] [[T3]] : $*Int32 on %0 : $E
-// CHECK:   [[ACCESS:%.*]] = begin_access [modify] [unsafe] [[MD]] : $*Int32
+// CHECK:   [[ACCESS:%.*]] = begin_access [modify] [unsafe] [[T3]] : $*Int32
 // CHECK:   store {{%.*}} to [[ACCESS]] : $*Int32
 func test_e(_ e: E) {
   e.value = 0
diff --git a/test/SILGen/assign_or_init_without_opaque_sil.swift b/test/SILGen/assign_or_init_without_opaque_sil.swift
new file mode 100644
index 0000000000000..5fd3b6b7b26f4
--- /dev/null
+++ b/test/SILGen/assign_or_init_without_opaque_sil.swift
@@ -0,0 +1,35 @@
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -disable-availability-checking -Xllvm -sil-full-demangle -primary-file %s | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-runtime
+
+// Extracted from opaque_values_closures.swift.
+// This version uses the assign_or_init SILGen instruction instead of the previous assign_by_wrapper.
+// Because init accessors do not currently support `-enable-sil-opaque-values`, 
+// this test runs without that flag to validate closure behavior in the local context.
+
+@propertyWrapper struct BoxWrapper<T> { var wrappedValue: T }
+
+// CHECK-LABEL: sil {{.*}}[ossa] @$s33assign_or_init_without_opaque_sil35captureBoxNonopaqueOwnedNonescapingyyxyXElF : {{.*}} {
+// CHECK:       bb0([[GET:%[^,]+]] :
+// CHECK:         [[BOX:%[^,]+]] = alloc_box $<τ_0_0> { var BoxWrapper<τ_0_0> } <U>, var
+// CHECK:         [[VAR:%[^,]+]] = mark_uninitialized [var] [[BOX]]
+// CHECK:         [[VAR_LIFETIME:%[^,]+]] = begin_borrow [lexical] [var_decl] [[VAR]]
+// CHECK:         [[VAR_ADDR:%[^,]+]] = project_box [[VAR_LIFETIME]]
+// TODO: DETERMINE: Considering that captureCanEscape is false, should this mark_function_escape be emitted?
+// CHECK:         mark_function_escape [[VAR_ADDR]]
+// CHECK:         [[LOCAL:%[^,]+]] = function_ref @$s33assign_or_init_without_opaque_sil35captureBoxNonopaqueOwnedNonescapingyyxyXElF5localL_yylF
+// CHECK:         apply [[LOCAL]]<U>([[VAR_LIFETIME]], [[GET]])
+// CHECK:         end_borrow [[VAR_LIFETIME]]
+// CHECK:         destroy_value [[VAR]]
+// CHECK-LABEL: } // end sil function '$s33assign_or_init_without_opaque_sil35captureBoxNonopaqueOwnedNonescapingyyxyXElF'
+
+// CHECK-LABEL: sil {{.*}}[ossa] @$s33assign_or_init_without_opaque_sil35captureBoxNonopaqueOwnedNonescapingyyxyXElF5localL_yylF : {{.*}}
+// CHECK:       bb0(%0 : @closureCapture @guaranteed $<τ_0_0> { var BoxWrapper<τ_0_0> } <U>, 
+// CHECK-SAME:      %1 :
+// CHECK-LABEL: } // end sil function '$s33assign_or_init_without_opaque_sil35captureBoxNonopaqueOwnedNonescapingyyxyXElF5localL_yylF'
+func captureBoxNonopaqueOwnedNonescaping<U>(_ get: () -> U) {
+  @BoxWrapper var u: U
+
+  func local() {
+    u = get()
+  }
+  local()
+}
diff --git a/test/SILGen/async_initializer.swift b/test/SILGen/async_initializer.swift
index 4893c98329b6a..56b96e9ee70ed 100644
--- a/test/SILGen/async_initializer.swift
+++ b/test/SILGen/async_initializer.swift
@@ -1,5 +1,8 @@
-// RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-silgen %s -module-name initializers -swift-version 5  -target %target-swift-5.1-abi-triple | %FileCheck %s --enable-var-scope --implicit-check-not=hop_to_executor
+// RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-silgen %s -module-name initializers -swift-version 5  -target %target-swift-5.1-abi-triple | %FileCheck -check-prefix=CHECK -check-prefix=NI %s --enable-var-scope --implicit-check-not=hop_to_executor
+// RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-silgen %s -module-name initializers -swift-version 5  -target %target-swift-5.1-abi-triple -enable-upcoming-feature NonisolatedNonsendingByDefault | %FileCheck %s -check-prefix=CHECK -check-prefix=NI-NS --enable-var-scope --implicit-check-not=hop_to_executor
+
 // REQUIRES: concurrency
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // CHECK:       protocol Person {
 // CHECK-NEXT:    init() async
@@ -18,12 +21,12 @@
 
 
 // CHECK:       class EarthPerson : Person {
-// CHECK-NEXT:    required init() async
+// CHECK-NEXT:    required {{.*}}init() async
 // CHECK-NEXT:    init(name: String) async
 
 // CHECK:       @_inheritsConvenienceInitializers class NorthAmericaPerson : EarthPerson {
-// CHECK-NEXT:    required init() async
-// CHECK-NEXT:    override init(name: String) async
+// CHECK-NEXT:    required {{.*}}init() async
+// CHECK-NEXT:    override {{.*}}init(name: String) async
 
 // CHECK:       class Cat {
 // CHECK-NEXT:    @MainActor init()
@@ -46,12 +49,14 @@ protocol Person {
 }
 
 struct MyStruct {
-  // CHECK-DAG: sil hidden [ossa] @$s12initializers8MyStructVACyYacfC : $@convention(method) @async (@thin MyStruct.Type) -> MyStruct
+  // NI-DAG: sil hidden [ossa] @$s12initializers8MyStructVACyYacfC : $@convention(method) @async (@thin MyStruct.Type) -> MyStruct
+  // NI-NS-DAG: sil hidden [ossa] @$s12initializers8MyStructVACyYacfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thin MyStruct.Type) -> MyStruct {
   init() async {}
 }
 
 enum MyEnum {
-  // CHECK-DAG: sil hidden [ossa] @$s12initializers6MyEnumOACyYacfC : $@convention(method) @async (@thin MyEnum.Type) -> MyEnum
+  // NI-DAG: sil hidden [ossa] @$s12initializers6MyEnumOACyYacfC : $@convention(method) @async (@thin MyEnum.Type) -> MyEnum
+  // NI-NS-DAG: sil hidden [ossa] @$s12initializers6MyEnumOACyYacfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thin MyEnum.Type) -> MyEnum {
   init() async {}
 }
 
@@ -59,35 +64,54 @@ actor MyActor {
   // CHECK-DAG:   sil hidden [ossa] @$s12initializers7MyActorCACyYacfc : $@convention(method) @async (@sil_isolated @owned MyActor) -> @owned MyActor
   // CHECK:       bb0(%0 : @owned $MyActor):
   //   In the prologue, hop to the generic executor.
-  // CHECK-NEXT:    [[NIL_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-  // CHECK-NEXT:    hop_to_executor [[NIL_EXECUTOR]] :
+  // CHECK-NEXT:       [[NIL_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+  // CHECK-NEXT:       hop_to_executor [[NIL_EXECUTOR]] :
   //   Later, when we return from an async call, hop to the
   //   correct flow-sensitive value.
-  // CHECK:         [[FN:%.*]] = function_ref @$s12initializers8MyStructVACyYacfC :
-  // CHECK-NEXT:    apply [[FN]]
-  // CHECK-NEXT:    [[ISOLATION:%.*]] = builtin "flowSensitiveSelfIsolation"<MyActor>({{%.*}})
-  // CHECK-NEXT:    hop_to_executor [[ISOLATION]]
-  // CHECK-NEXT:    destroy_value [[ISOLATION]]
+  //
+  // NI:         [[FN:%.*]] = function_ref @$s12initializers8MyStructVACyYacfC :
+  // NI-NEXT:    apply [[FN]]
+  //
+  // NI-NS:      [[ISOLATION_1:%.*]] = builtin "flowSensitiveSelfIsolation"<MyActor>({{%.*}})
+  // NI-NS-NEXT: // function_ref
+  // NI-NS-NEXT: [[FN:%.*]] = function_ref @$s12initializers8MyStructVACyYacfC :
+  // NI-NS-NEXT: apply [[FN]]([[ISOLATION_1]]
+  // NI-NS-NEXT: destroy_value [[ISOLATION_1]]
+  // CHECK-NEXT:       [[ISOLATION_2:%.*]] = builtin "flowSensitiveSelfIsolation"<MyActor>({{%.*}})
+  // CHECK-NEXT:       hop_to_executor [[ISOLATION_2]]
+  // CHECK: } // end sil function '$s12initializers7MyActorCACyYacfc'
   init() async {
     _ = await MyStruct()
   }
 }
 
 class EarthPerson : Person {
-  // CHECK-DAG: sil hidden [ossa] @$s12initializers11EarthPersonCACyYacfc : $@convention(method) @async (@owned EarthPerson) -> @owned EarthPerson
+  // NI-NS-LABEL: sil hidden [exact_self_class] [ossa] @$s12initializers11EarthPersonCACyYacfC : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thick EarthPerson.Type) -> @owned EarthPerson {
+  // NI-NS: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+  // NI-NS: hop_to_executor [[ACTOR]]
+  // NI-NS: apply {{%.*}}([[ACTOR]], {{%.*}})
+  // NI-NS: } // end sil function '$s12initializers11EarthPersonCACyYacfC'
+  
+
+  // NI-DAG: sil hidden [ossa] @$s12initializers11EarthPersonCACyYacfc : $@convention(method) @async (@owned EarthPerson) -> @owned EarthPerson
+  // NI-NS-DAG: sil hidden [ossa] @$s12initializers11EarthPersonCACyYacfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @owned EarthPerson) -> @owned EarthPerson {
   required init() async {}
 
-  // CHECK-DAG: sil hidden [ossa] @$s12initializers11EarthPersonC4nameACSS_tYacfc : $@convention(method) @async (@owned String, @owned EarthPerson) -> @owned EarthPerson
+  // NI-DAG: sil hidden [ossa] @$s12initializers11EarthPersonC4nameACSS_tYacfc : $@convention(method) @async (@owned String, @owned EarthPerson) -> @owned EarthPerson
+  // NI-NS-DAG: sil hidden [ossa] @$s12initializers11EarthPersonC4nameACSS_tYacfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @owned String, @owned EarthPerson) -> @owned EarthPerson {
   init(name: String) async {}
 
-  // CHECK-DAG: sil private [transparent] [thunk] [ossa] @$s12initializers11EarthPersonCAA0C0A2aDPxyYacfCTW : $@convention(witness_method: Person) @async (@thick EarthPerson.Type) -> @out EarthPerson
+  // NI-DAG: sil private [transparent] [thunk] [ossa] @$s12initializers11EarthPersonCAA0C0A2aDPxyYacfCTW : $@convention(
+  // NI-NS-DAG: sil private [transparent] [thunk] [ossa] @$s12initializers11EarthPersonCAA0C0A2aDPxyYacfCTW : $@convention(witness_method: Person) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @thick EarthPerson.Type) -> @out EarthPerson {
 }
 
 class NorthAmericaPerson : EarthPerson {
-  // CHECK-DAG: sil hidden [ossa] @$s12initializers18NorthAmericaPersonCACyYacfc : $@convention(method) @async (@owned NorthAmericaPerson) -> @owned NorthAmericaPerson
+  // NI-DAG: sil hidden [ossa] @$s12initializers18NorthAmericaPersonCACyYacfc : $@convention(method) @async (@owned NorthAmericaPerson) -> @owned NorthAmericaPerson
+  // NI-NS-DAG: sil hidden [ossa] @$s12initializers18NorthAmericaPersonCACyYacfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @owned NorthAmericaPerson) -> @owned NorthAmericaPerson {
   required init() async { await super.init() }
 
-  // CHECK-DAG: sil hidden [ossa] @$s12initializers18NorthAmericaPersonC4nameACSS_tYacfc : $@convention(method) @async (@owned String, @owned NorthAmericaPerson) -> @owned NorthAmericaPerson
+  // NI-DAG: sil hidden [ossa] @$s12initializers18NorthAmericaPersonC4nameACSS_tYacfc : $@convention(method) @async (@owned String, @owned NorthAmericaPerson) -> @owned NorthAmericaPerson
+  // NI-NS-DAG: sil hidden [ossa] @$s12initializers18NorthAmericaPersonC4nameACSS_tYacfc : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @owned String, @owned NorthAmericaPerson) -> @owned NorthAmericaPerson {
   override init(name: String) async { await super.init(name: name) }
 }
 
@@ -100,8 +124,10 @@ func someAsyncFn() async {}
 class Cat {
   // CHECK-LABEL:  sil hidden [ossa] @$s12initializers3CatCACyYacfc : $@convention(method) @async (@owned Cat) -> @owned Cat {
   // CHECK:          hop_to_executor {{%[0-9]+}} : $MainActor
-  // CHECK:          {{%[0-9]+}} = function_ref @$s12initializers11someAsyncFnyyYaF : $@convention(thin) @async () -> ()
-  // CHECK:          {{%[0-9]+}} = apply {{%[0-9]+}}() : $@convention(thin) @async () -> ()
+  // CHECK:          {{%[0-9]+}} = function_ref @$s12initializers11someAsyncFnyyYaF :
+  // NI:             {{%[0-9]+}} = apply {{%[0-9]+}}() : $@convention(thin) @async () -> ()
+  // NI-NS:          {{%[0-9]+}} = apply {{%[0-9]+}}({{%.*}}) : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+  // NI-NS-NEXT:     destroy_value {{%.*}}
   // CHECK-NEXT:     hop_to_executor {{%[0-9]+}} : $MainActor
   // CHECK:        } // end sil function '$s12initializers3CatCACyYacfc'
   @MainActor init() async {
@@ -114,8 +140,10 @@ class Cat {
 struct Dog {
   // CHECK-LABEL:  sil hidden [ossa] @$s12initializers3DogVACyYacfC : $@convention(method) @async (@thin Dog.Type) -> Dog {
   // CHECK:          hop_to_executor {{%[0-9]+}} : $MainActor
-  // CHECK:          {{%[0-9]+}} = function_ref @$s12initializers11someAsyncFnyyYaF : $@convention(thin) @async () -> ()
-  // CHECK:          {{%[0-9]+}} = apply {{%[0-9]+}}() : $@convention(thin) @async () -> ()
+  // CHECK:          {{%[0-9]+}} = function_ref @$s12initializers11someAsyncFnyyYaF
+  // NI:             {{%[0-9]+}} = apply {{%[0-9]+}}() : $@convention(thin) @async () -> ()
+  // NI-NS:          {{%[0-9]+}} = apply {{%[0-9]+}}({{%.*}}) : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+  // NI-NS-NEXT:     destroy_value {{%.*}}
   // CHECK-NEXT:     hop_to_executor {{%[0-9]+}} : $MainActor
   // CHECK:        } // end sil function '$s12initializers3DogVACyYacfC'
   @MainActor init() async {
@@ -128,9 +156,10 @@ struct Dog {
 enum Birb {
   // CHECK-LABEL:  sil hidden [ossa] @$s12initializers4BirbOACyYacfC : $@convention(method) @async (@thin Birb.Type) -> Birb {
   // CHECK:          hop_to_executor {{%[0-9]+}} : $MainActor
-  // CHECK:          {{%[0-9]+}} = function_ref @$s12initializers11someAsyncFnyyYaF : $@convention(thin) @async () -> ()
-  // CHECK:          {{%[0-9]+}} = apply {{%[0-9]+}}() : $@convention(thin) @async () -> ()
-  // CHECK-NEXT:     hop_to_executor {{%[0-9]+}} : $MainActor
+  // CHECK:          {{%[0-9]+}} = function_ref @$s12initializers11someAsyncFnyyYaF :
+  // NI:             {{%[0-9]+}} = apply {{%[0-9]+}}() : $@convention(thin) @async () -> ()
+  // NI-NS:          {{%[0-9]+}} = apply {{%[0-9]+}}({{%.*}}) :
+  // CHECK:          hop_to_executor {{%[0-9]+}} : $MainActor
   // CHECK:        } // end sil function '$s12initializers4BirbOACyYacfC'
   @MainActor init() async {
     await someAsyncFn()
@@ -139,38 +168,67 @@ enum Birb {
   @MainActor init(name: String) {}
 }
 
-// CHECK-LABEL:  sil hidden [ossa] @$s12initializers7makeCatyyYaF : $@convention(thin) @async () -> () {
-// CHECK:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:          hop_to_executor [[BORROWED_EXECUTOR:%[0-9]+]]
-// CHECK:          end_borrow [[BORROWED_EXECUTOR]]
-// CHECK-NEXT:     {{%[0-9]+}} = apply {{%[0-9]+}}({{%[0-9]+}}, {{%[0-9]+}}) : $@convention(method) (@owned String, @thick Cat.Type) -> @owned Cat
-// CHECK:          hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:        } // end sil function '$s12initializers7makeCatyyYaF'
+// NI-LABEL:  sil hidden [ossa] @$s12initializers7makeCatyyYaF : $@convention(thin) @async () -> () {
+// NI:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:          hop_to_executor [[BORROWED_EXECUTOR:%[0-9]+]]
+// NI:          end_borrow [[BORROWED_EXECUTOR]]
+// NI-NEXT:     {{%[0-9]+}} = apply {{%[0-9]+}}({{%[0-9]+}}, {{%[0-9]+}}) : $@convention(method) (@owned String, @thick Cat.Type) -> @owned Cat
+// NI:          hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:        } // end sil function '$s12initializers7makeCatyyYaF'
+
+// NI-NS-LABEL:  sil hidden [ossa] @$s12initializers7makeCatyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// NI-NS:        bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>):
+// NI-NS:          hop_to_executor [[ACTOR]]
+// NI-NS:          [[INIT:%.*]] = function_ref @$s12initializers3CatC4nameACSS_tcfC : $@convention(method) (@owned String, @thick Cat.Type) -> @owned Cat
+// NI-NS:          [[MAIN_ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// NI-NS:          [[MAIN_ACTOR_B:%.*]] = begin_borrow [[MAIN_ACTOR]]
+// NI-NS:          hop_to_executor [[MAIN_ACTOR_B]]
+// NI-NS:          {{%[0-9]+}} = apply [[INIT]]({{%[0-9]+}}, {{%[0-9]+}}) : $@convention(method) (@owned String, @thick Cat.Type) -> @owned Cat
+// NI-NS:          hop_to_executor [[ACTOR]]
+// NI-NS:        } // end sil function '$s12initializers7makeCatyyYaF'
 func makeCat() async {
   _ = await Cat(name: "Socks")
 }
 
-// CHECK-LABEL:  sil hidden [ossa] @$s12initializers7makeDogyyYaF : $@convention(thin) @async () -> () {
-// CHECK:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:          hop_to_executor [[BORROWED_EXEC:%.*]] :
-// CHECK-NEXT:     end_borrow [[BORROWED_EXEC]]
-// CHECK-NEXT:     {{%[0-9]+}} = apply {{%[0-9]+}}({{%[0-9]+}}, {{%[0-9]+}}) : $@convention(method) (@owned String, @thin Dog.Type) -> Dog
-// CHECK:          hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:        } // end sil function '$s12initializers7makeDogyyYaF'
+// NI-LABEL:  sil hidden [ossa] @$s12initializers7makeDogyyYaF : $@convention(thin) @async () -> () {
+// NI:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:          hop_to_executor [[BORROWED_EXEC:%.*]] :
+// NI-NEXT:     end_borrow [[BORROWED_EXEC]]
+// NI-NEXT:     {{%[0-9]+}} = apply {{%[0-9]+}}({{%[0-9]+}}, {{%[0-9]+}}) : $@convention(method) (@owned String, @thin Dog.Type) -> Dog
+// NI:          hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:        } // end sil function '$s12initializers7makeDogyyYaF'
+
+// NI-NS-LABEL: sil hidden [ossa] @$s12initializers7makeDogyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// NI-NS: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>):
+// NI-NS:      hop_to_executor [[ACTOR]]
+// NI-NS:      hop_to_executor [[BORROWED_EXEC:%.*]] :
+// NI-NS-NEXT: end_borrow [[BORROWED_EXEC]]
+// NI-NS-NEXT: {{%[0-9]+}} = apply {{%[0-9]+}}({{%[0-9]+}}, {{%[0-9]+}}) : $@convention(method) (@owned String, @thin Dog.Type) -> Dog
+// NI-NS:      hop_to_executor [[ACTOR]]
+// NI-NS: } // end sil function '$s12initializers7makeDogyyYaF'
 func makeDog() async {
   _ = await Dog(name: "Lassie")
 }
 
-// CHECK-LABEL:  sil hidden [ossa] @$s12initializers8makeBirbyyYaF : $@convention(thin) @async () -> () {
-// CHECK:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:          hop_to_executor [[BORROWED_EXEC:%.*]] : $MainActor
-// CHECK-NEXT:     end_borrow [[BORROWED_EXEC]]
-// CHECK-NEXT:     {{%[0-9]+}} = apply {{%[0-9]+}}({{%[0-9]+}}, {{%[0-9]+}}) : $@convention(method) (@owned String, @thin Birb.Type) -> Birb
-// CHECK:          hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:        } // end sil function '$s12initializers8makeBirbyyYaF'
+// NI-LABEL:  sil hidden [ossa] @$s12initializers8makeBirbyyYaF : $@convention(thin) @async () -> () {
+// NI:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:          hop_to_executor [[BORROWED_EXEC:%.*]] : $MainActor
+// NI-NEXT:     end_borrow [[BORROWED_EXEC]]
+// NI-NEXT:     {{%[0-9]+}} = apply {{%[0-9]+}}({{%[0-9]+}}, {{%[0-9]+}}) : $@convention(method) (@owned String, @thin Birb.Type) -> Birb
+// NI:          hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:        } // end sil function '$s12initializers8makeBirbyyYaF'
+
+// NI-NS-LABEL:  sil hidden [ossa] @$s12initializers8makeBirbyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// NI-NS:        bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>):
+// NI-NS-NEXT:     hop_to_executor [[ACTOR]]
+// NI-NS:          hop_to_executor [[BORROWED_EXEC:%.*]] : $MainActor
+// NI-NS-NEXT:     end_borrow [[BORROWED_EXEC]]
+// NI-NS-NEXT:     {{%[0-9]+}} = apply {{%[0-9]+}}({{%[0-9]+}}, {{%[0-9]+}}) : $@convention(method) (@owned String, @thin Birb.Type) -> Birb
+// NI-NS:          hop_to_executor [[ACTOR]]
+// NI-NS:        } // end sil function '$s12initializers8makeBirbyyYaF'
 func makeBirb() async {
   _ = await Birb(name: "Chirpy")
 }
@@ -201,42 +259,82 @@ func makeActor() async -> SomeActor {
   return await SomeActor()
 }
 
-// CHECK-LABEL: sil hidden [ossa] @$s12initializers20makeActorFromGenericAA04SomeC0CyYaF : $@convention(thin) @async () -> @owned SomeActor {
-// CHECK:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:          apply
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI-LABEL: sil hidden [ossa] @$s12initializers20makeActorFromGenericAA04SomeC0CyYaF : $@convention(thin) @async () -> @owned SomeActor {
+// NI:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:          apply
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI: } // end sil function '$s12initializers20makeActorFromGenericAA04SomeC0CyYaF'
+
+// NI-NS-LABEL: sil hidden [ossa] @$s12initializers20makeActorFromGenericAA04SomeC0CyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> @owned SomeActor {
+// NI-NS:      bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>):
+// NI-NS:          hop_to_executor [[ACTOR]]
+// NI-NS:          apply {{%.*}}({{%.*}})
+// NI-NS-NEXT:     hop_to_executor [[ACTOR]]
+// NI-NS: } // end sil function '$s12initializers20makeActorFromGenericAA04SomeC0CyYaF'
 func makeActorFromGeneric() async -> SomeActor {
   return await SomeActor()
 }
 
-// CHECK-LABEL: sil hidden [ossa] @$s12initializers26callActorMethodFromGeneric1ayAA04SomeC0C_tYaF : $@convention(thin) @async (@guaranteed SomeActor) -> () {
-// CHECK:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:          apply
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI-LABEL: sil hidden [ossa] @$s12initializers26callActorMethodFromGeneric1ayAA04SomeC0C_tYaF :
+// NI:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:          apply
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI: } // end sil function '$s12initializers26callActorMethodFromGeneric1ayAA04SomeC0C_tYaF'
+
+// NI-NS-LABEL: sil hidden [ossa] @$s12initializers26callActorMethodFromGeneric1ayAA04SomeC0C_tYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SomeActor) -> () {
+// NI-NS:       bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : @guaranteed $SomeActor):
+// NI-NS:          hop_to_executor [[ACTOR]]
+// NI-NS:          [[FUNC:%.*]] = class_method [[ARG]]
+// NI-NS:          apply [[FUNC]]([[ARG]])
+// NI-NS-NEXT:     hop_to_executor [[ACTOR]]
+// NI-NS: } // end sil function '$s12initializers26callActorMethodFromGeneric1ayAA04SomeC0C_tYaF'
 func callActorMethodFromGeneric(a: SomeActor) async {
   await a.someMethod()
 }
 
-// CHECK-LABEL: sil hidden {{.*}} @$s12initializers15makeActorInTaskyyYaF : $@convention(thin) @async () -> () {
-// CHECK:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:          apply
-// CHECK-LABEL: sil private [ossa] @$s12initializers15makeActorInTaskyyYaFAA04SomeC0CyYacfU_ : $@convention(thin) @async @substituted <τ_0_0> (@guaranteed Optional<any Actor>) -> @out τ_0_0 for <SomeActor> {
-// CHECK:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:          apply
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI-LABEL: sil hidden {{.*}} @$s12initializers15makeActorInTaskyyYaF : $@convention(thin) @async () -> () {
+// NI:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:          apply
+// NI: } // end sil function '$s12initializers15makeActorInTaskyyYaF'
+
+// NI-NS-LABEL: sil hidden{{.*}} [ossa] @$s12initializers15makeActorInTaskyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
+// NI-NS:       bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>):
+// NI-NS:          hop_to_executor [[ACTOR]]
+// NI-NS:          apply
+// NI-NS: } // end sil function '$s12initializers15makeActorInTaskyyYaF'
+
+// NI-LABEL: sil private [ossa] @$s12initializers15makeActorInTaskyyYaFAA04SomeC0CyYacfU_ : $@convention(thin) @async @substituted <τ_0_0> (@guaranteed Optional<any Actor>) -> @out τ_0_0 for <SomeActor> {
+// NI:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:          apply
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI: } // end sil function '$s12initializers15makeActorInTaskyyYaFAA04SomeC0CyYacfU_'
+
+// NI-NS-LABEL: sil private [ossa] @$s12initializers15makeActorInTaskyyYaFAA04SomeC0CyYacfU_ : $@convention(thin) @async @substituted <τ_0_0> (@guaranteed Optional<any Actor>) -> @out τ_0_0 for <SomeActor> {
+// NI-NS:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+// NI-NS-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI-NS:          apply
+// NI-NS-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI-NS: } // end sil function '$s12initializers15makeActorInTaskyyYaFAA04SomeC0CyYacfU_'
 @available(SwiftStdlib 5.1, *)
 func makeActorInTask() async {
   Task.detached { await SomeActor() }
 }
 
-// CHECK-LABEL: sil hidden {{.*}}  @$s12initializers21callActorMethodInTask1ayAA04SomeC0C_tYaF : $@convention(thin) @async (@guaranteed SomeActor) -> () {
-// CHECK:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-// CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
-// CHECK:          apply
+// NI-LABEL: sil hidden {{.*}}  @$s12initializers21callActorMethodInTask1ayAA04SomeC0C_tYaF : $@convention(thin) @async (@guaranteed SomeActor) -> () {
+// NI:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+// NI-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
+// NI:          apply
+// NI: } // end sil function '$s12initializers21callActorMethodInTask1ayAA04SomeC0C_tYaF'
+
+// NI-NS-LABEL: sil hidden{{.*}} [ossa] @$s12initializers21callActorMethodInTask1ayAA04SomeC0C_tYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SomeActor) -> () {
+// NI-NS: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : @guaranteed $SomeActor):
+// NI-NS:   hop_to_executor [[ACTOR]]
+// NI-NS: } // end sil function '$s12initializers21callActorMethodInTask1ayAA04SomeC0C_tYaF'
+
 // CHECK-LABEL: sil private [ossa] @$s12initializers21callActorMethodInTask1ayAA04SomeC0C_tYaFyyYacfU_ : $@convention(thin) @async @substituted <τ_0_0> (@guaranteed Optional<any Actor>, @guaranteed SomeActor) -> @out τ_0_0 for <()> {
 // CHECK:          [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
 // CHECK-NEXT:     hop_to_executor [[GENERIC_EXEC]] : $Optional<Builtin.Executor>
diff --git a/test/SILGen/availability_disabled.swift b/test/SILGen/availability_disabled.swift
deleted file mode 100644
index d305aa2cefe11..0000000000000
--- a/test/SILGen/availability_disabled.swift
+++ /dev/null
@@ -1,5 +0,0 @@
-// RUN: %target-swift-emit-silgen -disable-availability-checking %s -verify
-
-func foo() {
-    if #available(macOS 10.15, *) {}
-}
diff --git a/test/SILGen/availability_disabled_zippered.swift b/test/SILGen/availability_disabled_zippered.swift
deleted file mode 100644
index b67b42d9a471c..0000000000000
--- a/test/SILGen/availability_disabled_zippered.swift
+++ /dev/null
@@ -1,6 +0,0 @@
-// RUN: %target-swift-emit-silgen -target %target-cpu-apple-macosx13 -target-variant %target-cpu-apple-ios16-macabi -disable-availability-checking %s -verify
-// REQUIRES: OS=macosx
-
-func foo() {
-    if #available(macOS 10.15, *) {}
-}
diff --git a/test/SILGen/availability_overloads.swift b/test/SILGen/availability_overloads.swift
index 66a8742eb7470..b9e1e4e11093c 100644
--- a/test/SILGen/availability_overloads.swift
+++ b/test/SILGen/availability_overloads.swift
@@ -52,19 +52,34 @@ public class BeforeAndAfter {
 
 
 // Make sure we can generate calls to these overloads, too
-_ = BeforeAndAfter(foo: ())
-_ = try BeforeAndAfter()
-_ = try BeforeAndAfter.foo()
-_ = BeforeAndAfter.computed
-BeforeAndAfter.computed = 10
-_ = try BeforeAndAfter().computed
-try BeforeAndAfter().computed = 10
+public func testLocal() throws {
+  _ = BeforeAndAfter(foo: ())
+  _ = try BeforeAndAfter()
+  _ = try BeforeAndAfter.foo()
+  _ = BeforeAndAfter.computed
+  BeforeAndAfter.computed = 10
+  _ = try BeforeAndAfter().computed
+  try BeforeAndAfter().computed = 10
+}
+
+@available(swift, obsoleted: 4.0)
+public func testLocalObsoleted() throws {
+  _ = BeforeAndAfter(foo: ())
+  _ = try BeforeAndAfter()
+  _ = try BeforeAndAfter.foo()
+  _ = BeforeAndAfter.computed
+  BeforeAndAfter.computed = 10
+  _ = try BeforeAndAfter().computed
+  try BeforeAndAfter().computed = 10
+}
 
 // Same thing but in a different module
-_ = BeforeAndAfterOther(foo: ())
-_ = try BeforeAndAfterOther()
-_ = try BeforeAndAfterOther.foo()
-_ = BeforeAndAfterOther.computed
-BeforeAndAfterOther.computed = 10
-_ = try BeforeAndAfterOther().computed
-try BeforeAndAfterOther().computed = 10
+public func testOtherModule() throws {
+  _ = BeforeAndAfterOther(foo: ())
+  _ = try BeforeAndAfterOther()
+  _ = try BeforeAndAfterOther.foo()
+  _ = BeforeAndAfterOther.computed
+  BeforeAndAfterOther.computed = 10
+  _ = try BeforeAndAfterOther().computed
+  try BeforeAndAfterOther().computed = 10
+}
diff --git a/test/SILGen/availability_query.swift b/test/SILGen/availability_query.swift
index 2f92ac8c93d5f..28e8586c1a503 100644
--- a/test/SILGen/availability_query.swift
+++ b/test/SILGen/availability_query.swift
@@ -109,6 +109,11 @@ if #available(OSX 10, *) {
 if #unavailable(OSX 10) {
 }
 
+// CHECK: [[TRUE:%.*]] = integer_literal $Builtin.Int1, -1
+// CHECK: cond_br [[TRUE]]
+if #available(macOS 0) { // expected-warning {{expected version number}}
+}
+
 // CHECK: }
 
 func doThing() {}
diff --git a/test/SILGen/availability_query_custom_domains.swift b/test/SILGen/availability_query_custom_domains.swift
new file mode 100644
index 0000000000000..6aeddd68043cf
--- /dev/null
+++ b/test/SILGen/availability_query_custom_domains.swift
@@ -0,0 +1,187 @@
+// RUN: %target-swift-emit-silgen -module-name Test %s -verify \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -define-enabled-availability-domain EnabledDomain \
+// RUN:   -define-always-enabled-availability-domain AlwaysEnabledDomain \
+// RUN:   -define-disabled-availability-domain DisabledDomain \
+// RUN:   -define-dynamic-availability-domain DynamicDomain \
+// RUN:   | %FileCheck %s
+
+// REQUIRES: swift_feature_CustomAvailability
+
+@available(EnabledDomain)
+public func availableInEnabledDomain() { }
+
+@available(EnabledDomain, unavailable)
+public func unavailableInEnabledDomain() { }
+
+@available(AlwaysEnabledDomain)
+public func availableInAlwaysEnabledDomain() { }
+
+@available(AlwaysEnabledDomain, unavailable)
+public func unavailableInAlwaysEnabledDomain() { }
+
+@available(DisabledDomain)
+public func availableInDisabledDomain() { }
+
+@available(DisabledDomain, unavailable)
+public func unavailableInDisabledDomain() { }
+
+@available(DynamicDomain)
+public func availableInDynamicDomain() { }
+
+@available(DynamicDomain, unavailable)
+public func unavailableInDynamicDomain() { }
+
+// CHECK-LABEL: sil{{.*}}$s4Test28testIfAvailableEnabledDomainyyF : $@convention(thin) () -> ()
+public func testIfAvailableEnabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, -1
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @$s4Test24availableInEnabledDomainyyF
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @$s4Test26unavailableInEnabledDomainyyF
+  if #available(EnabledDomain) {
+    availableInEnabledDomain()
+  } else {
+    unavailableInEnabledDomain()
+  }
+}
+// CHECK: end sil function '$s4Test28testIfAvailableEnabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test30testIfUnavailableEnabledDomainyyF : $@convention(thin) () -> ()
+public func testIfUnavailableEnabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, 0
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @$s4Test26unavailableInEnabledDomainyyF
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @$s4Test24availableInEnabledDomainyyF
+  if #unavailable(EnabledDomain) {
+    unavailableInEnabledDomain()
+  } else {
+    availableInEnabledDomain()
+  }
+}
+// CHECK: end sil function '$s4Test30testIfUnavailableEnabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test34testIfAvailableAlwaysEnabledDomainyyF : $@convention(thin) () -> ()
+public func testIfAvailableAlwaysEnabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, -1
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @$s4Test30availableInAlwaysEnabledDomainyyF
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @$s4Test32unavailableInAlwaysEnabledDomainyyF
+  if #available(AlwaysEnabledDomain) {
+    availableInAlwaysEnabledDomain()
+  } else {
+    unavailableInAlwaysEnabledDomain()
+  }
+}
+// CHECK: end sil function '$s4Test34testIfAvailableAlwaysEnabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test36testIfUnavailableAlwaysEnabledDomainyyF : $@convention(thin) () -> ()
+public func testIfUnavailableAlwaysEnabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, 0
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @$s4Test32unavailableInAlwaysEnabledDomainyyF
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @$s4Test30availableInAlwaysEnabledDomainyyF
+  if #unavailable(AlwaysEnabledDomain) {
+    unavailableInAlwaysEnabledDomain()
+  } else {
+    availableInAlwaysEnabledDomain()
+  }
+}
+// CHECK: end sil function '$s4Test36testIfUnavailableAlwaysEnabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test29testIfAvailableDisabledDomainyyF : $@convention(thin) () -> ()
+public func testIfAvailableDisabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, 0
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @$s4Test25availableInDisabledDomainyyF
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @$s4Test27unavailableInDisabledDomainyyF
+  if #available(DisabledDomain) {
+    availableInDisabledDomain()
+  } else {
+    unavailableInDisabledDomain()
+  }
+}
+// CHECK: end sil function '$s4Test29testIfAvailableDisabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test31testIfUnavailableDisabledDomainyyF : $@convention(thin) () -> ()
+public func testIfUnavailableDisabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, -1
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @$s4Test27unavailableInDisabledDomainyyF
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @$s4Test25availableInDisabledDomainyyF
+  if #unavailable(DisabledDomain) {
+    unavailableInDisabledDomain()
+  } else {
+    availableInDisabledDomain()
+  }
+}
+// CHECK: end sil function '$s4Test31testIfUnavailableDisabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test28testIfAvailableDynamicDomainyyF : $@convention(thin) () -> ()
+public func testIfAvailableDynamicDomain() {
+  // FIXME: [availability] Call dynamic domain predicate function
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, -1
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @$s4Test24availableInDynamicDomainyyF
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @$s4Test26unavailableInDynamicDomainyyF
+  if #available(DynamicDomain) {
+    availableInDynamicDomain()
+  } else {
+    unavailableInDynamicDomain()
+  }
+}
+// CHECK: end sil function '$s4Test28testIfAvailableDynamicDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test30testIfUnavailableDynamicDomainyyF : $@convention(thin) () -> ()
+public func testIfUnavailableDynamicDomain() {
+  // FIXME: [availability] Call dynamic domain predicate function
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, 0
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @$s4Test26unavailableInDynamicDomainyyF
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @$s4Test24availableInDynamicDomainyyF
+  if #unavailable(DynamicDomain) {
+    unavailableInDynamicDomain()
+  } else {
+    availableInDynamicDomain()
+  }
+}
+// CHECK: end sil function '$s4Test30testIfUnavailableDynamicDomainyyF'
diff --git a/test/SILGen/availability_query_custom_domains_clang.swift b/test/SILGen/availability_query_custom_domains_clang.swift
new file mode 100644
index 0000000000000..71beb7399605a
--- /dev/null
+++ b/test/SILGen/availability_query_custom_domains_clang.swift
@@ -0,0 +1,132 @@
+// RUN: %target-swift-emit-silgen -module-name Test %s -verify \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -import-bridging-header %S/Inputs/AvailabilityDomains.h \
+// RUN:   | %FileCheck %s
+
+// REQUIRES: swift_feature_CustomAvailability
+
+// CHECK-LABEL: sil{{.*}}$s4Test28testIfAvailableEnabledDomainyyF : $@convention(thin) () -> ()
+public func testIfAvailableEnabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, -1
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @available_in_enabled_domain
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @unavailable_in_enabled_domain
+  if #available(EnabledDomain) {
+    available_in_enabled_domain()
+  } else {
+    unavailable_in_enabled_domain()
+  }
+}
+// CHECK: end sil function '$s4Test28testIfAvailableEnabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test30testIfUnavailableEnabledDomainyyF : $@convention(thin) () -> ()
+public func testIfUnavailableEnabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, 0
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @unavailable_in_enabled_domain
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @available_in_enabled_domain
+  if #unavailable(EnabledDomain) {
+    unavailable_in_enabled_domain()
+  } else {
+    available_in_enabled_domain()
+  }
+}
+// CHECK: end sil function '$s4Test30testIfUnavailableEnabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test29testIfAvailableDisabledDomainyyF : $@convention(thin) () -> ()
+public func testIfAvailableDisabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, 0
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @available_in_disabled_domain
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @unavailable_in_disabled_domain
+  if #available(DisabledDomain) {
+    available_in_disabled_domain()
+  } else {
+    unavailable_in_disabled_domain()
+  }
+}
+// CHECK: end sil function '$s4Test29testIfAvailableDisabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test31testIfUnavailableDisabledDomainyyF : $@convention(thin) () -> ()
+public func testIfUnavailableDisabledDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, -1
+  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @unavailable_in_disabled_domain
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @available_in_disabled_domain
+  if #unavailable(DisabledDomain) {
+    unavailable_in_disabled_domain()
+  } else {
+    available_in_disabled_domain()
+  }
+}
+// CHECK: end sil function '$s4Test31testIfUnavailableDisabledDomainyyF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test28testIfAvailableDynamicDomainyyF : $@convention(thin) () -> ()
+public func testIfAvailableDynamicDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[QUERY_FUNC:%.*]] = function_ref @$sSC33__swift_DynamicDomain_isAvailableBi1_yF : $@convention(thin) () -> Builtin.Int1
+  // CHECK:   [[QUERY_RESULT:%.*]] = apply [[QUERY_FUNC]]() : $@convention(thin) () -> Builtin.Int1
+  // CHECK:   cond_br [[QUERY_RESULT]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @available_in_dynamic_domain
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @unavailable_in_dynamic_domain
+  if #available(DynamicDomain) {
+    available_in_dynamic_domain()
+  } else {
+    unavailable_in_dynamic_domain()
+  }
+}
+// CHECK: end sil function '$s4Test28testIfAvailableDynamicDomainyyF'
+
+// CHECK-LABEL: sil non_abi [serialized] [ossa] @$sSC33__swift_DynamicDomain_isAvailableBi1_yF : $@convention(thin) () -> Builtin.Int1
+// CHECK: bb0:
+// CHECK:   [[QUERY_FUNC:%.*]] = function_ref @__DynamicDomain_isAvailable : $@convention(c) () -> Bool
+// CHECK:   [[QUERY_RESULT:%.*]] = apply [[QUERY_FUNC]]() : $@convention(c) () -> Bool
+// CHECK:   [[RESULT:%.*]] = struct_extract [[QUERY_RESULT]], #Bool._value
+// CHECK:   return [[RESULT]]
+// CHECK: end sil function '$sSC33__swift_DynamicDomain_isAvailableBi1_yF'
+
+// CHECK-LABEL: sil{{.*}}$s4Test30testIfUnavailableDynamicDomainyyF : $@convention(thin) () -> ()
+public func testIfUnavailableDynamicDomain() {
+  // CHECK: bb0:
+  // CHECK:   [[QUERY_FUNC:%.*]] = function_ref @$sSC33__swift_DynamicDomain_isAvailableBi1_yF : $@convention(thin) () -> Builtin.Int1
+  // CHECK:   [[QUERY_RESULT:%.*]] = apply [[QUERY_FUNC]]() : $@convention(thin) () -> Builtin.Int1
+  // CHECK:   [[MINUSONE:%.*]] = integer_literal $Builtin.Int1, -1
+  // CHECK:   [[QUERY_INVERSION:%.*]] = builtin "xor_Int1"([[QUERY_RESULT]], [[MINUSONE]]) : $Builtin.Int1
+  // CHECK:   cond_br [[QUERY_INVERSION]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
+
+  // CHECK: [[TRUE_BB]]:
+  // CHECK:   function_ref @unavailable_in_dynamic_domain
+
+  // CHECK: [[FALSE_BB]]:
+  // CHECK:   function_ref @available_in_dynamic_domain
+  if #unavailable(DynamicDomain) {
+    unavailable_in_dynamic_domain()
+  } else {
+    available_in_dynamic_domain()
+  }
+}
+// CHECK: end sil function '$s4Test30testIfUnavailableDynamicDomainyyF'
diff --git a/test/SILGen/availability_query_disabled.swift b/test/SILGen/availability_query_disabled.swift
new file mode 100644
index 0000000000000..fbbeccee9afd0
--- /dev/null
+++ b/test/SILGen/availability_query_disabled.swift
@@ -0,0 +1,16 @@
+// RUN: %target-swift-emit-silgen -disable-availability-checking %s -verify
+// RUN: %target-swift-emit-silgen -disable-availability-checking %s | %FileCheck %s
+
+// CHECK-LABEL: // available()
+func available() {
+  // CHECK: [[TRUE:%.*]] = integer_literal $Builtin.Int1, -1
+  // CHECK: cond_br [[TRUE]]
+  if #available(macOS 10.15, *) {}
+}
+
+// CHECK-LABEL: // unavailable()
+func unavailable() {
+  // CHECK: [[FALSE:%.*]] = integer_literal $Builtin.Int1, 0
+  // CHECK: cond_br [[FALSE]]
+  if #unavailable(macOS 10.15) {}
+}
diff --git a/test/SILGen/availability_query_disabled_zippered.swift b/test/SILGen/availability_query_disabled_zippered.swift
new file mode 100644
index 0000000000000..01caeddf862b4
--- /dev/null
+++ b/test/SILGen/availability_query_disabled_zippered.swift
@@ -0,0 +1,21 @@
+// RUN: %target-swift-emit-silgen -target %target-cpu-apple-macosx13 -target-variant %target-cpu-apple-ios16-macabi -disable-availability-checking %s -verify
+// RUN: %target-swift-emit-silgen -target-variant %target-cpu-apple-macosx13 -target %target-cpu-apple-ios16-macabi -disable-availability-checking %s -verify
+
+// RUN: %target-swift-emit-silgen -target %target-cpu-apple-macosx13 -target-variant %target-cpu-apple-ios16-macabi -disable-availability-checking %s | %FileCheck %s
+// RUN: %target-swift-emit-silgen -target-variant %target-cpu-apple-macosx13 -target %target-cpu-apple-ios16-macabi -disable-availability-checking %s | %FileCheck %s
+
+// REQUIRES: OS=macosx || OS=maccatalyst
+
+// CHECK-LABEL: // available()
+func available() {
+  // CHECK: [[TRUE:%.*]] = integer_literal $Builtin.Int1, -1
+  // CHECK: cond_br [[TRUE]]
+  if #available(macOS 10.15, *) {}
+}
+
+// CHECK-LABEL: // unavailable()
+func unavailable() {
+  // CHECK: [[FALSE:%.*]] = integer_literal $Builtin.Int1, 0
+  // CHECK: cond_br [[FALSE]]
+  if #unavailable(macOS 10.15) {}
+}
diff --git a/test/SILGen/availability_query_maccatalyst.swift b/test/SILGen/availability_query_maccatalyst.swift
index 18713162ee926..9e0c5192665c1 100644
--- a/test/SILGen/availability_query_maccatalyst.swift
+++ b/test/SILGen/availability_query_maccatalyst.swift
@@ -25,3 +25,11 @@ if #available(OSX 10.53.8, iOS 51.1.2, *) {
 // CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MAJOR]], [[MINOR]], [[PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
 if #available(OSX 10.53.8, iOS 51.1.2, macCatalyst 53.2.3, *) {
 }
+
+// If there's no iOS or macCatalyst version, then the condition trivially
+// evaluates to true
+
+// CHECK: [[TRUE:%.*]] = integer_literal $Builtin.Int1, -1
+// CHECK: cond_br [[TRUE]]
+if #available(OSX 10.53.8, *) {
+}
diff --git a/test/SILGen/availability_query_maccatalyst_zippered.swift b/test/SILGen/availability_query_maccatalyst_zippered.swift
index a2f698c1ea773..9dc9e10741f0a 100644
--- a/test/SILGen/availability_query_maccatalyst_zippered.swift
+++ b/test/SILGen/availability_query_maccatalyst_zippered.swift
@@ -1,11 +1,11 @@
-// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-macosx10.52 -target-variant %target-cpu-apple-ios50.0-macabi | %FileCheck %s
-// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-ios50.0-macabi -target-variant %target-cpu-apple-macosx10.52 | %FileCheck %s
+// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-macosx10.52 -target-variant %target-cpu-apple-ios50.0-macabi | %FileCheck %s --check-prefixes=CHECK,CHECK-NO-BACKDEPLOY-MAC
+// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-ios50.0-macabi -target-variant %target-cpu-apple-macosx10.52 | %FileCheck %s --check-prefixes=CHECK,CHECK-NO-BACKDEPLOY-MAC
 
-// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-macosx10.14.4 -target-variant %target-cpu-apple-ios50.0-macabi | %FileCheck %s --check-prefix=CHECK-BACKDEPLOY-MAC
-// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-ios50.0-macabi -target-variant %target-cpu-apple-macosx10.14.4 | %FileCheck %s --check-prefix=CHECK-BACKDEPLOY-MAC
+// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-macosx10.14.4 -target-variant %target-cpu-apple-ios50.0-macabi | %FileCheck %s --check-prefixes=CHECK,CHECK-BACKDEPLOY-MAC
+// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-ios50.0-macabi -target-variant %target-cpu-apple-macosx10.14.4 | %FileCheck %s --check-prefixes=CHECK,CHECK-BACKDEPLOY-MAC
 
-// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-macosx10.15 -target-variant %target-cpu-apple-ios50.0-macabi | %FileCheck %s --check-prefix=CHECK-DEPLOY10_15-MAC
-// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-ios50.0-macabi -target-variant %target-cpu-apple-macosx10.15 | %FileCheck %s --check-prefix=CHECK-DEPLOY10_15-MAC
+// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-macosx10.15 -target-variant %target-cpu-apple-ios50.0-macabi | %FileCheck %s --check-prefixes=CHECK,CHECK-NO-BACKDEPLOY-MAC
+// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-ios50.0-macabi -target-variant %target-cpu-apple-macosx10.15 | %FileCheck %s --check-prefixes=CHECK,CHECK-NO-BACKDEPLOY-MAC
 
 // REQUIRES: OS=macosx || OS=maccatalyst
 
@@ -17,6 +17,7 @@
 // version in an macCatalyst process and against the macOS version
 // in a macOS process.
 
+// CHECK-LABEL: // zippered()
 // CHECK: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
 // CHECK: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 53
 // CHECK: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 8
@@ -25,11 +26,32 @@
 // CHECK: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
 // CHECK: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
 // CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
-if #available(OSX 10.53.8, iOS 51.1.2, *) {
+// CHECK: cond_br [[QUERY_RESULT]]
+func zippered() {
+  if #available(OSX 10.53.8, iOS 51.1.2, *) {
+  }
+}
+
+// CHECK-LABEL: // zippered_unavailable()
+// CHECK: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
+// CHECK: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 53
+// CHECK: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 8
+// CHECK: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 51
+// CHECK: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
+// CHECK: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[MINUSONE:%.*]] = integer_literal $Builtin.Int1, -1
+// CHECK: [[QUERY_INVERSION:%.*]] = builtin "xor_Int1"([[QUERY_RESULT]], [[MINUSONE]]) : $Builtin.Int1
+// CHECK: cond_br [[QUERY_INVERSION]]
+func zippered_unavailable() {
+  if #unavailable(OSX 10.53.8, iOS 51.1.2) {
+  }
 }
 
 // Make sure macCatalyst wins over iOS.
 
+// CHECK-LABEL: // macCatalystWins()
 // CHECK: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
 // CHECK: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 53
 // CHECK: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 8
@@ -38,82 +60,126 @@ if #available(OSX 10.53.8, iOS 51.1.2, *) {
 // CHECK: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 5
 // CHECK: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
 // CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
-if #available(OSX 10.53.8, iOS 51.1.2, macCatalyst 52.3.5, *) {
+// CHECK: cond_br [[QUERY_RESULT]]
+func macCatalystWins() {
+  if #available(OSX 10.53.8, iOS 51.1.2, macCatalyst 52.3.5, *) {
+  }
 }
 
+// CHECK-LABEL: // noMatch()
 // CHECK: [[TRUE:%.*]] = integer_literal $Builtin.Int1, -1
 // CHECK: cond_br [[TRUE]]
 // The '*' matches for both macOS and macCatalyst, so the condition
 // should always be true.
-if #available(tvOS 9.0, *) {
+func noMatch() {
+  if #available(tvOS 9.0, *) {
+  }
+}
+
+// CHECK-LABEL: // noMatch_unavailable()
+// CHECK: [[FALSE:%.*]] = integer_literal $Builtin.Int1, 0
+// CHECK: cond_br [[FALSE]]
+func noMatch_unavailable() {
+  if #unavailable(tvOS 9.0) {
+  }
 }
 
+// CHECK-LABEL: // macOSOnly()
 // CHECK: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
 // CHECK: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 54
 // CHECK: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 3
 // CHECK: [[QUERY_FUNC:%.*]] = function_ref @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
 // CHECK: [[QUERY_RESULT:%.*]] = apply [[QUERY_FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: cond_br [[QUERY_RESULT]]
 // The '*' matches for iOS, so we only need to check to check the
 // macOS version and thus use the primary target version check
 // entrypoint.
-if #available(macOS 10.54.3, *) {
+func macOSOnly() {
+  if #available(macOS 10.54.3, *) {
+  }
 }
 
-// CHECK: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
-// CHECK: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
-// CHECK: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
-// CHECK: [[QUERY_FUNC:%.*]] = function_ref @$ss33_stdlib_isVariantOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
-// CHECK: [[QUERY_RESULT:%.*]] = apply [[QUERY_FUNC]]([[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK-LABEL: // macOSOnly_unavailable()
+// CHECK: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
+// CHECK: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 54
+// CHECK: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 3
+// CHECK: [[QUERY_FUNC:%.*]] = function_ref @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[QUERY_RESULT:%.*]] = apply [[QUERY_FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[MINUSONE:%.*]] = integer_literal $Builtin.Int1, -1
+// CHECK: [[QUERY_INVERSION:%.*]] = builtin "xor_Int1"([[QUERY_RESULT]], [[MINUSONE]]) : $Builtin.Int1
+// CHECK: cond_br [[QUERY_INVERSION]]
+func macOSOnly_unavailable() {
+  if #unavailable(macOS 10.54.3) {
+  }
+}
+
+// CHECK-LABEL: // iOSOnly()
+// CHECK-NO-BACKDEPLOY-MAC:  [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
+// CHECK-NO-BACKDEPLOY-NEXT: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
+// CHECK-NO-BACKDEPLOY-NEXT: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
+// CHECK-NO-BACKDEPLOY: [[QUERY_FUNC:%.*]] = function_ref @$ss33_stdlib_isVariantOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK-NO-BACKDEPLOY: [[QUERY_RESULT:%.*]] = apply [[QUERY_FUNC]]([[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK-NO-BACKDEPLOY: cond_br [[QUERY_RESULT]]
+
+// CHECK-BACKDEPLOY-MAC:      [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
+// CHECK-BACKDEPLOY-MAC-NEXT: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 14
+// CHECK-BACKDEPLOY-MAC-NEXT: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 4
+// CHECK-BACKDEPLOY-MAC-NEXT: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
+// CHECK-BACKDEPLOY-MAC-NEXT: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
+// CHECK-BACKDEPLOY-MAC-NEXT: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
+// CHECK-BACKDEPLOY-MAC: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK-BACKDEPLOY-MAC: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK-BACKDEPLOY-MAC: cond_br [[QUERY_RESULT]]
 // The '*' matches for macOS, so we only need to check to check the
 // iOS version and thus use the variant target version check
 // entrypoint.
-if #available(iOS 54.7.2, *) {
-}
 
 // The ss33_stdlib_isVariantOSVersionAtLeastyBi1_Bw_BwBwtF entry point only exists
 // on macOS 10.15+, so apply the optimization to omit the macOS version if the macOS
 // deployment target is earlier than 10.15. In this case, use the
 // ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF
 // entry point, which is present in 10.14.4 and is part of the Swift 5.0 ABI.
-
-// CHECK-BACKDEPLOY-MAC-LABEL: // backdeployMacStar()
-// CHECK-BACKDEPLOY-MAC: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
-// CHECK-BACKDEPLOY-MAC: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 14
-// CHECK-BACKDEPLOY-MAC: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 4
-// CHECK-BACKDEPLOY-MAC: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
-// CHECK-BACKDEPLOY-MAC: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
-// CHECK-BACKDEPLOY-MAC: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
-// CHECK-BACKDEPLOY-MAC: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
-// CHECK-BACKDEPLOY-MAC: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
-// CHECK-DEPLOY10_15-MAC-LABEL: // backdeployMacStar()
-// CHECK-DEPLOY10_15-MAC: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
-// CHECK-DEPLOY10_15-MAC: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
-// CHECK-DEPLOY10_15-MAC: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
-// CHECK-DEPLOY10_15-MAC: [[QUERY_FUNC:%.*]] = function_ref @$ss33_stdlib_isVariantOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
-// CHECK-DEPLOY10_15-MAC: [[QUERY_RESULT:%.*]] = apply [[QUERY_FUNC]]([[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
-func backdeployMacStar() {
+func iOSOnly() {
   if #available(iOS 54.7.2, *) {
   }
 }
 
-// CHECK-BACKDEPLOY-MAC-LABEL: // backdeployMacExplicit()
-// CHECK-BACKDEPLOY-MAC: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
-// CHECK-BACKDEPLOY-MAC: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 14
-// CHECK-BACKDEPLOY-MAC: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 5
-// CHECK-BACKDEPLOY-MAC: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
-// CHECK-BACKDEPLOY-MAC: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
-// CHECK-BACKDEPLOY-MAC: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
+// CHECK-LABEL: // iOSOnly_unavailable()
+// CHECK-NO-BACKDEPLOY-MAC:  [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
+// CHECK-NO-BACKDEPLOY-NEXT: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
+// CHECK-NO-BACKDEPLOY-NEXT: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
+// CHECK-NO-BACKDEPLOY: [[QUERY_FUNC:%.*]] = function_ref @$ss33_stdlib_isVariantOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK-NO-BACKDEPLOY: [[QUERY_RESULT:%.*]] = apply [[QUERY_FUNC]]([[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK-NO-BACKDEPLOY: [[MINUSONE:%.*]] = integer_literal $Builtin.Int1, -1
+// CHECK-NO-BACKDEPLOY: [[QUERY_INVERSION:%.*]] = builtin "xor_Int1"([[QUERY_RESULT]], [[MINUSONE]]) : $Builtin.Int1
+// CHECK-NO-BACKDEPLOY: cond_br [[QUERY_INVERSION]]
+
+// CHECK-BACKDEPLOY-MAC:      [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
+// CHECK-BACKDEPLOY-MAC-NEXT: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 14
+// CHECK-BACKDEPLOY-MAC-NEXT: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 4
+// CHECK-BACKDEPLOY-MAC-NEXT: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
+// CHECK-BACKDEPLOY-MAC-NEXT: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
+// CHECK-BACKDEPLOY-MAC-NEXT: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
 // CHECK-BACKDEPLOY-MAC: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
 // CHECK-BACKDEPLOY-MAC: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
-// CHECK-DEPLOY10_15-MAC-LABEL: // backdeployMacExplicit()
-// CHECK-DEPLOY10_15-MAC: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
-// CHECK-DEPLOY10_15-MAC: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 14
-// CHECK-DEPLOY10_15-MAC: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 5
-// CHECK-DEPLOY10_15-MAC: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
-// CHECK-DEPLOY10_15-MAC: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
-// CHECK-DEPLOY10_15-MAC: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
-// CHECK-DEPLOY10_15-MAC: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
-// CHECK-DEPLOY10_15-MAC: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK-BACKDEPLOY-MAC: [[MINUSONE:%.*]] = integer_literal $Builtin.Int1, -1
+// CHECK-BACKDEPLOY-MAC: [[QUERY_INVERSION:%.*]] = builtin "xor_Int1"([[QUERY_RESULT]], [[MINUSONE]]) : $Builtin.Int1
+// CHECK-BACKDEPLOY-MAC: cond_br [[QUERY_INVERSION]]
+func iOSOnly_unavailable() {
+  if #unavailable(iOS 54.7.2) {
+  }
+}
+
+// CHECK-LABEL: // backdeployMacExplicit()
+// CHECK:      [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
+// CHECK-NEXT: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 14
+// CHECK-NEXT: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 5
+// CHECK-NEXT: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 54
+// CHECK-NEXT: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 7
+// CHECK-NEXT: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
+// CHECK: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: cond_br [[QUERY_RESULT]]
 func backdeployMacExplicit() {
   if #available(iOS 54.7.2, macOS 10.14.5, *) {
   }
diff --git a/test/SILGen/availability_query_maccatalyst_zippered_canonical_versions.swift b/test/SILGen/availability_query_maccatalyst_zippered_canonical_versions.swift
index 56a73749d847b..9d24c0aa20657 100644
--- a/test/SILGen/availability_query_maccatalyst_zippered_canonical_versions.swift
+++ b/test/SILGen/availability_query_maccatalyst_zippered_canonical_versions.swift
@@ -1,15 +1,11 @@
-// RUN: %target-swift-emit-silgen %s -target x86_64-apple-macosx10.52 -target-variant x86_64-apple-ios50.0-macabi | %FileCheck %s
-// RUN: %target-swift-emit-silgen %s -target x86_64-apple-ios50.0-macabi -target-variant x86_64-apple-macosx10.52 | %FileCheck %s
+// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-macosx10.15 -target-variant %target-cpu-apple-ios13.1-macabi | %FileCheck %s
+// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-ios13.1-macabi -target-variant %target-cpu-apple-macosx10.15 | %FileCheck %s
 
 
 // REQUIRES: OS=macosx || OS=maccatalyst
 
 // CHECK-LABEL: sil{{.+}}@main{{.*}} {
 
-
-// Test for the runtime non-canonical version hack for canonical macOS versioning.
-// This will eventually change to be the correctly canonicalized version.
-
 // CHECK: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 10
 // CHECK: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 16
 // CHECK: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 0
@@ -20,3 +16,36 @@
 // CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
 if #available(OSX 10.16, iOS 51.1.2, *) {
 }
+
+// CHECK: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 11
+// CHECK: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 51
+// CHECK: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 2
+// CHECK: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+if #available(OSX 11.0, iOS 51.1.2, *) {
+}
+
+// CHECK: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 16
+// CHECK: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 19
+// CHECK: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+if #available(macOS 16.0, iOS 19.0, *) {
+}
+
+// CHECK: [[MACOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 26
+// CHECK: [[MACOS_MINOR:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[MACOS_PATCH:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[IOS_MAJOR:%.*]] = integer_literal $Builtin.Word, 26
+// CHECK: [[IOS_MINOR:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[IOS_PATCH:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[FUNC:%.*]] = function_ref @$ss042_stdlib_isOSVersionAtLeastOrVariantVersiondE0yBi1_Bw_BwBwBwBwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MACOS_MAJOR]], [[MACOS_MINOR]], [[MACOS_PATCH]], [[IOS_MAJOR]], [[IOS_MINOR]], [[IOS_PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+if #available(macOS 26.0, iOS 26.0, *) {
+}
diff --git a/test/SILGen/availability_query_macosx_canonical_versions.swift b/test/SILGen/availability_query_macosx_canonical_versions.swift
index becbe903eb6b1..c72e31bb5e95b 100644
--- a/test/SILGen/availability_query_macosx_canonical_versions.swift
+++ b/test/SILGen/availability_query_macosx_canonical_versions.swift
@@ -1,17 +1,38 @@
-// RUN: %target-swift-emit-sil %s -target %target-cpu-apple-macosx10.50 -verify
-// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-macosx10.50 | %FileCheck %s
+// RUN: %target-swift-emit-sil %s -target %target-cpu-apple-macosx10.15 -verify
+// RUN: %target-swift-emit-silgen %s -target %target-cpu-apple-macosx10.15 | %FileCheck %s
 
 // REQUIRES: OS=macosx
 
 // CHECK-LABEL: sil{{.+}}@main{{.*}} {
 
-// Test for the runtime non-canonical version hack for canonical macOS versioning.
-// This will eventually change to be the correctly canonicalized version.
-
 // CHECK: [[MAJOR:%.*]] = integer_literal $Builtin.Word, 10
 // CHECK: [[MINOR:%.*]] = integer_literal $Builtin.Word, 16
 // CHECK: [[PATCH:%.*]] = integer_literal $Builtin.Word, 0
 // CHECK: [[FUNC:%.*]] = function_ref @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
 // CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MAJOR]], [[MINOR]], [[PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
 if #available(OSX 10.16, iOS 7.1, *) {
-}
\ No newline at end of file
+}
+
+// CHECK: [[MAJOR:%.*]] = integer_literal $Builtin.Word, 11
+// CHECK: [[MINOR:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[PATCH:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[FUNC:%.*]] = function_ref @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MAJOR]], [[MINOR]], [[PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+if #available(OSX 11.0, *) {
+}
+
+// CHECK: [[MAJOR:%.*]] = integer_literal $Builtin.Word, 16
+// CHECK: [[MINOR:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[PATCH:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[FUNC:%.*]] = function_ref @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MAJOR]], [[MINOR]], [[PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+if #available(macOS 16.0, *) {
+}
+
+// CHECK: [[MAJOR:%.*]] = integer_literal $Builtin.Word, 26
+// CHECK: [[MINOR:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[PATCH:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK: [[FUNC:%.*]] = function_ref @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+// CHECK: [[QUERY_RESULT:%.*]] = apply [[FUNC]]([[MAJOR]], [[MINOR]], [[PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+if #available(macOS 26.0, *) {
+}
diff --git a/test/SILGen/back_deployed_attr.swift b/test/SILGen/back_deployed_attr.swift
index 068a231e8c0af..928e5ea987e61 100644
--- a/test/SILGen/back_deployed_attr.swift
+++ b/test/SILGen/back_deployed_attr.swift
@@ -85,3 +85,30 @@ public func backDeployedCaller(_ s: inout S<Z>) {
   // CHECK: function_ref @$s11back_deploy1SV1xxvsTwb : $@convention(method) <τ_0_0> (@in τ_0_0, @inout S<τ_0_0>) -> ()
   s.x = Z()
 }
+
+// The same bug from test/Concurrency/nonisolated_nonsending.swift also applied to
+// back-deployment thunks.
+
+// CHECK-LABEL: sil non_abi [serialized] [back_deployed_thunk] [ossa] @$s11back_deploy0A29DeployedNonisolatedNonsendingSiyYaFTwb :
+@backDeployed(before: macOS 10.52)
+nonisolated(nonsending)
+public func backDeployedNonisolatedNonsending() async -> Int {
+  // CHECK: bb0(%0 : @guaranteed $Optional<any Actor>):
+  // CHECK:   [[FALLBACK_FN:%.*]] = function_ref @$s11back_deploy0A29DeployedNonisolatedNonsendingSiyYaFTwB :
+  // CHECK:   apply [[FALLBACK_FN]](%0)
+  // CHECK:   [[SHIPPING_FN:%.*]] = function_ref @$s11back_deploy0A29DeployedNonisolatedNonsendingSiyYaF :
+  // CHECK:   apply [[SHIPPING_FN]](%0)
+  return 0
+}
+
+// CHECK-LABEL: sil non_abi [serialized] [back_deployed_thunk] [ossa] @$s11back_deploy0A32DeployedBeforeVersionMappingTo26SiyFTwb :
+@backDeployed(before: macOS 16)
+public func backDeployedBeforeVersionMappingTo26() -> Int {
+  // CHECK: [[MAJOR:%.*]] = integer_literal $Builtin.Word, 26
+  // CHECK: [[MINOR:%.*]] = integer_literal $Builtin.Word, 0
+  // CHECK: [[PATCH:%.*]] = integer_literal $Builtin.Word, 0
+  // CHECK: [[OSVFN:%.*]] = function_ref @$ss26_stdlib_isOSVersionAtLeastyBi1_Bw_BwBwtF : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+  // CHECK: [[AVAIL:%.*]] = apply [[OSVFN]]([[MAJOR]], [[MINOR]], [[PATCH]]) : $@convention(thin) (Builtin.Word, Builtin.Word, Builtin.Word) -> Builtin.Int1
+  // CHECK: cond_br [[AVAIL]]
+  return 0
+}
diff --git a/test/attr/back_deployed_attr_func_visionos.swift b/test/SILGen/back_deployed_attr_func_visionos.swift
similarity index 90%
rename from test/attr/back_deployed_attr_func_visionos.swift
rename to test/SILGen/back_deployed_attr_func_visionos.swift
index bd3d88aaa1330..93068623eb694 100644
--- a/test/attr/back_deployed_attr_func_visionos.swift
+++ b/test/SILGen/back_deployed_attr_func_visionos.swift
@@ -1,5 +1,5 @@
 // RUN: %target-swift-emit-sil -parse-as-library -module-name back_deploy %s -target %target-cpu-apple-xros1.0 -verify
-// RUN: %target-swift-emit-silgen -parse-as-library -module-name back_deploy %s -target %target-cpu-apple-xros1.0 | %FileCheck %s
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -parse-as-library -module-name back_deploy %s -target %target-cpu-apple-xros1.0 | %FileCheck %s
 
 // REQUIRES: OS=xros
 
@@ -10,7 +10,7 @@
 // CHECK:   return [[RESULT]] : $()
 
 // -- Back deployment thunk for trivialFunc()
-// CHECK-LABEL: sil non_abi [serialized] [thunk] [ossa] @$s11back_deploy11trivialFuncyyFTwb : $@convention(thin) () -> ()
+// CHECK-LABEL: sil non_abi [serialized] [back_deployed_thunk] [ossa] @$s11back_deploy11trivialFuncyyFTwb : $@convention(thin) () -> ()
 // CHECK: bb0:
 // CHECK:   [[MAJOR:%.*]] = integer_literal $Builtin.Word, 2
 // CHECK:   [[MINOR:%.*]] = integer_literal $Builtin.Word, 0
@@ -45,7 +45,7 @@ public func trivialFunc() {}
 // CHECK:   return [[RESULT]] : $()
 
 // -- Back deployment thunk for trivialFunc_iOS()
-// CHECK-LABEL: sil non_abi [serialized] [thunk] [ossa] @$s11back_deploy15trivialFunc_iOSyyFTwb : $@convention(thin) () -> ()
+// CHECK-LABEL: sil non_abi [serialized] [back_deployed_thunk] [ossa] @$s11back_deploy15trivialFunc_iOSyyFTwb : $@convention(thin) () -> ()
 // CHECK: bb0:
 // CHECK:   [[MAJOR:%.*]] = integer_literal $Builtin.Word, 1
 // CHECK:   [[MINOR:%.*]] = integer_literal $Builtin.Word, 1
diff --git a/test/SILGen/bitwise_copyable_stdlib.swift b/test/SILGen/bitwise_copyable_stdlib.swift
index 66621a40e371c..9d477f122c7fc 100644
--- a/test/SILGen/bitwise_copyable_stdlib.swift
+++ b/test/SILGen/bitwise_copyable_stdlib.swift
@@ -7,11 +7,11 @@
 // RUN:     -module-name Swift                               \
 // RUN:     -disable-availability-checking                   \
 // RUN:     -enable-experimental-feature BuiltinModule       \
-// RUN:     -enable-experimental-feature LifetimeDependence  \
+// RUN:     -enable-experimental-feature Lifetimes  \
 // RUN:     -enable-builtin-module
 
 // REQUIRES: swift_feature_BuiltinModule
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // Force verification of TypeLowering's isTrivial.
 
diff --git a/test/SILGen/borrow_accessor.swift b/test/SILGen/borrow_accessor.swift
new file mode 100644
index 0000000000000..99fbbd5d61bac
--- /dev/null
+++ b/test/SILGen/borrow_accessor.swift
@@ -0,0 +1,840 @@
+// RUN:%target-swift-frontend -emit-silgen %s -enable-experimental-feature BorrowAndMutateAccessors | %FileCheck %s
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+
+public final class Klass {}
+
+public struct NC : ~Copyable {}
+
+func use(_ t: Klass) {}
+
+func use(_ t: borrowing NC) {}
+
+public struct S {
+  var _k: Klass
+
+  var k: Klass {
+    borrow {
+      return _k
+    }
+    mutate {
+      return &_k
+    }
+  }
+}
+
+public struct Wrapper {
+  var _k: Klass
+  var _s: S
+
+  var s: S {
+    borrow {
+      return _s
+    }
+    mutate {
+      return &_s
+    }
+  }
+
+  var k: Klass {
+    borrow {
+      return _k
+    }
+    mutate {
+      return &_k
+    }
+  }
+
+  var nested_borrow1: Klass {
+    borrow {
+      return _s.k
+    }
+    mutate {
+      return &s._k
+    }
+  }
+
+  var nested_borrow2: Klass {
+    borrow {
+      return k
+    }
+    mutate {
+      return &_k
+    }
+  }
+
+  subscript(index: Int) -> Klass {
+    borrow {
+      return _k
+    }
+    mutate {
+      return &_k
+    }
+  }
+
+  var nested_subscript: Klass {
+    borrow {
+      return self[0]
+    }
+    mutate {
+      return &self[0]
+    }
+  }
+
+  var literal: Int {
+    borrow {
+      return 0
+    }
+  }
+}
+
+public struct SimpleWrapper<T> {
+  var _prop: T
+
+  var prop: T {
+    borrow {
+      return _prop
+    }
+    mutate {
+      return &_prop
+    }
+  }
+}
+
+public struct GenWrapper<T> {
+  var _prop: T
+  var _w: SimpleWrapper<T>
+  var _k: Klass
+  var _s: S
+
+  public var prop: T {
+    borrow {
+      return _prop
+    }
+    mutate {
+      return &_prop
+    }
+  }
+
+  var s: S {
+    borrow {
+      return _s
+    }
+    mutate {
+      return &_s
+    }
+  }
+
+  var k: Klass {
+    borrow {
+      return _k
+    }
+    mutate {
+      return &_k
+    }
+  }
+
+  var nested_prop1: T {
+    borrow {
+      return _w.prop
+    }
+    mutate {
+      return &_w.prop
+    }
+  }
+
+  var nested_prop2: T {
+    borrow {
+      return prop
+    }
+    mutate {
+      return &prop
+    }
+  }
+
+  var nested_k1: Klass {
+    borrow {
+      return _s.k
+    }
+    mutate {
+      return &_s.k
+    }
+  }
+
+  var nested_k2: Klass {
+    borrow {
+      return s.k
+    }
+    mutate {
+      return &s.k
+    }
+  }
+
+  subscript(index: Int) -> T {
+    borrow {
+      return _prop
+    }
+    mutate {
+      return &_prop
+    }
+  }
+
+  var nested_subscript: T {
+    borrow {
+      return self[0]
+    }
+    mutate {
+      return &self[0]
+    }
+  }
+
+  var literal: Int {
+    borrow {
+      return 0
+    }
+  }
+}
+
+public struct NCS: ~Copyable {
+  var _nc: NC
+
+  var nc: NC {
+    borrow {
+      return _nc
+    }
+    mutate {
+      return &_nc
+    }
+  }
+}
+
+public struct NCWrapper: ~Copyable {
+  var _nc: NC
+  var _s: NCS
+
+  var nc: NC {
+    borrow {
+      return _nc
+    }
+    mutate {
+      return &_nc
+    }
+  }
+
+  var nested1: NC {
+    borrow {
+      return _s.nc
+    }
+    mutate {
+      return &_s.nc
+    }
+  }
+
+  var nested2: NC {
+    borrow {
+      return nc
+    }
+    mutate {
+      return &nc
+    }
+  }
+
+  subscript(index: Int) -> NC {
+    borrow {
+      return _nc
+    }
+    mutate {
+      return &_nc
+    }
+  }
+
+  var nested_subscript: NC {
+    borrow {
+      return self[0]
+    }
+    mutate {
+      return &self[0]
+    }
+  }
+
+  var literal: Int {
+    borrow {
+      return 0
+    }
+  }
+}
+
+public struct SimpleNCWrapper<T : ~Copyable> : ~Copyable {
+  var _prop: T
+
+  var prop: T {
+    borrow {
+      return _prop
+    }
+    mutate {
+      return &_prop
+    }
+  }
+}
+
+public struct GenNCWrapper<T : ~Copyable> : ~Copyable {
+  var _prop: T
+  var _w: SimpleNCWrapper<T>
+  var _nc: NC
+  var _ncw: NCWrapper
+
+  public var prop: T {
+    borrow {
+      return _prop
+    }
+    mutate {
+      return &_prop
+    }
+  }
+
+  var nc: NC {
+    borrow {
+      return _nc
+    }
+    mutate {
+      return &_nc
+    }
+  }
+
+  var ncw: NCWrapper {
+    borrow {
+      return _ncw
+    }
+    mutate {
+      return &_ncw
+    }
+  }
+
+  var nested_prop1: T {
+    borrow {
+      return _w.prop
+    }
+    mutate {
+      return &_w.prop
+    }
+  }
+
+  var nested_prop2: T {
+    borrow {
+      return prop
+    }
+    mutate {
+      return &prop
+    }
+  }
+
+  var nested_nc1: NC {
+    borrow {
+      return _ncw.nc
+    }
+    mutate {
+      return &_ncw.nc
+    }
+  }
+
+  var nested_nc2: NC {
+    borrow {
+      return ncw.nc
+    }
+    mutate {
+      return &ncw.nc
+    }
+  }
+
+  subscript(index: Int) -> T {
+    borrow {
+      return _prop
+    }
+    mutate {
+      return &_prop
+    }
+  }
+
+  var nested_subscript: T {
+    borrow {
+      return self[0]
+    }
+    mutate {
+      return &self[0]
+    }
+  }
+
+  var literal: Int {
+    borrow {
+      return 0
+    }
+  }
+}
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV1sAA1SVvb : $@convention(method) (@guaranteed Wrapper) -> @guaranteed S {
+// CHECK: bb0([[REG0:%.*]] : @guaranteed $Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1
+// CHECK:   [[REG2:%.*]] = struct_extract [[REG0]], #Wrapper._s
+// CHECK:   return [[REG2]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV1sAA1SVvz : $@convention(method) (@inout Wrapper) -> @guaranteed_addr S {
+// CHECK:bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = struct_element_addr [[REG0]], #Wrapper._s
+// CHECK:  return [[REG2]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV1kAA5KlassCvb : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : @guaranteed $Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1
+// CHECK:   [[REG2:%.*]] = struct_extract [[REG0]], #Wrapper._k
+// CHECK:   return [[REG2]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV1kAA5KlassCvz : $@convention(method) (@inout Wrapper) -> @guaranteed_addr Klass {
+// CHECK:bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = struct_element_addr [[REG0]], #Wrapper._k
+// CHECK:  return [[REG2]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV14nested_borrow1AA5KlassCvb : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : @guaranteed $Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1
+// CHECK:   [[REG2:%.*]] = struct_extract [[REG0]], #Wrapper._s
+// CHECK:   [[REG3:%.*]] = function_ref @$s15borrow_accessor1SV1kAA5KlassCvb : $@convention(method) (@guaranteed S) -> @guaranteed Klass
+// CHECK:   [[REG4:%.*]] = apply [[REG3]]([[REG2]]) : $@convention(method) (@guaranteed S) -> @guaranteed Klass
+// CHECK:   return [[REG4]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV14nested_borrow1AA5KlassCvz : $@convention(method) (@inout Wrapper) -> @guaranteed_addr Klass {
+// CHECK:bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = function_ref @$s15borrow_accessor7WrapperV1sAA1SVvz : $@convention(method) (@inout Wrapper) -> @guaranteed_addr S
+// CHECK:  [[REG3:%.*]] = apply [[REG2]]([[REG0]]) : $@convention(method) (@inout Wrapper) -> @guaranteed_addr S
+// CHECK:  [[REG4:%.*]] = struct_element_addr [[REG3]], #S._k
+// CHECK:  return [[REG4]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV14nested_borrow2AA5KlassCvb : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : @guaranteed $Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1
+// CHECK:   [[REG2:%.*]] = function_ref @$s15borrow_accessor7WrapperV1kAA5KlassCvb : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   [[REG3:%.*]] = apply [[REG2]]([[REG0]]) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV14nested_borrow2AA5KlassCvz : $@convention(method) (@inout Wrapper) -> @guaranteed_addr Klass {
+// CHECK:bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = struct_element_addr [[REG0]], #Wrapper._k
+// CHECK:  return [[REG2]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperVyAA5KlassCSicib : $@convention(method) (Int, @guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : @guaranteed $Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "index", argno 1
+// CHECK:   debug_value [[REG1]], let, name "self", argno 2
+// CHECK:   [[REG4:%.*]] = struct_extract [[REG1]], #Wrapper._k
+// CHECK:   return [[REG4]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperVyAA5KlassCSiciz : $@convention(method) (Int, @inout Wrapper) -> @guaranteed_addr Klass {
+// CHECK:bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*Wrapper):
+// CHECK:  debug_value [[REG0]], let, name "index", argno 1
+// CHECK:  debug_value [[REG1]], var, name "self", argno 2, expr op_deref
+// CHECK:  [[REG4:%.*]] = struct_element_addr [[REG1]], #Wrapper._k
+// CHECK:  return [[REG4]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV16nested_subscriptAA5KlassCvb : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : @guaranteed $Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1
+// CHECK:   [[REG2:%.*]] = integer_literal $Builtin.IntLiteral, 0
+// CHECK:   [[REG3:%.*]] = metatype $@thin Int.Type
+// CHECK:   [[REG4:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG5:%.*]] = apply [[REG4]]([[REG2]], [[REG3]]) : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG6:%.*]] = function_ref @$s15borrow_accessor7WrapperVyAA5KlassCSicib : $@convention(method) (Int, @guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   [[REG7:%.*]] = apply [[REG6]]([[REG5]], [[REG0]]) : $@convention(method) (Int, @guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   return [[REG7]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor7WrapperV16nested_subscriptAA5KlassCvz : $@convention(method) (@inout Wrapper) -> @guaranteed_addr Klass {
+// CHECK:bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = integer_literal $Builtin.IntLiteral, 0
+// CHECK:  [[REG3:%.*]] = metatype $@thin Int.Type
+// CHECK:  [[REG4:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:  [[REG5:%.*]] = apply [[REG4]]([[REG2]], [[REG3]]) : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:  [[REG6:%.*]] = function_ref @$s15borrow_accessor7WrapperVyAA5KlassCSiciz : $@convention(method) (Int, @inout Wrapper) -> @guaranteed_addr Klass
+// CHECK:  [[REG7:%.*]] = apply [[REG6]]([[REG5]], [[REG0]]) : $@convention(method) (Int, @inout Wrapper) -> @guaranteed_addr Klass
+// CHECK:  return [[REG7]]
+// CHECK: }
+
+// CHECK: sil [ossa] @$s15borrow_accessor10GenWrapperV4propxvb : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed_addr T {
+// CHECK: bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._prop
+// CHECK:   return [[REG2]]
+// CHECK: }
+
+// CHECK: sil [ossa] @$s15borrow_accessor10GenWrapperV4propxvz : $@convention(method) <T> (@inout GenWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._prop
+// CHECK:  return [[REG2]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV1sAA1SVvb : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed S {
+// CHECK: bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._s
+// CHECK:   [[REG3:%.*]] = load_borrow [[REG2]]
+// CHECK:   [[REG4:%.*]] = unchecked_ownership_conversion [[REG3]], @guaranteed to @unowned
+// CHECK:   [[REG5:%.*]] = unchecked_ownership_conversion [[REG4]], @unowned to @guaranteed
+// CHECK:   end_borrow [[REG3]]
+// CHECK:   return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV1sAA1SVvz : $@convention(method) <T> (@inout GenWrapper<T>) -> @guaranteed_addr S {
+// CHECK:bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._s
+// CHECK:  return [[REG2]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV1kAA5KlassCvb : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._k
+// CHECK:   [[REG3:%.*]] = load_borrow [[REG2]]
+// CHECK:   [[REG4:%.*]] = unchecked_ownership_conversion [[REG3]], @guaranteed to @unowned
+// CHECK:   [[REG5:%.*]] = unchecked_ownership_conversion [[REG4]], @unowned to @guaranteed
+// CHECK:   end_borrow [[REG3]]
+// CHECK:   return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV1kAA5KlassCvz : $@convention(method) <T> (@inout GenWrapper<T>) -> @guaranteed_addr Klass {
+// CHECK:bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._k
+// CHECK:  return [[REG2]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV12nested_prop1xvb : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed_addr T {
+// CHECK: bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._w
+// CHECK:   [[REG3:%.*]] = function_ref @$s15borrow_accessor13SimpleWrapperV4propxvb : $@convention(method) <τ_0_0> (@in_guaranteed SimpleWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   [[REG4:%.*]] = apply [[REG3]]<T>([[REG2]]) : $@convention(method) <τ_0_0> (@in_guaranteed SimpleWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   return [[REG4]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV12nested_prop1xvz : $@convention(method) <T> (@inout GenWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._w
+// CHECK:  [[REG3:%.*]] = function_ref @$s15borrow_accessor13SimpleWrapperV4propxvz : $@convention(method) <τ_0_0> (@inout SimpleWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG4:%.*]] = apply [[REG3]]<T>([[REG2]]) : $@convention(method) <τ_0_0> (@inout SimpleWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  return [[REG4]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV12nested_prop2xvb : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed_addr T {
+// CHECK: bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = function_ref @$s15borrow_accessor10GenWrapperV4propxvb : $@convention(method) <τ_0_0> (@in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   [[REG3:%.*]] = apply [[REG2]]<T>([[REG0]]) : $@convention(method) <τ_0_0> (@in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV9nested_k1AA5KlassCvb : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._s
+// CHECK:   [[REG3:%.*]] = load_borrow [[REG2]]
+// CHECK:   [[REG4:%.*]] = function_ref @$s15borrow_accessor1SV1kAA5KlassCvb : $@convention(method) (@guaranteed S) -> @guaranteed Klass
+// CHECK:   [[REG5:%.*]] = apply [[REG4]]([[REG3]]) : $@convention(method) (@guaranteed S) -> @guaranteed Klass
+// CHECK:   [[REG6:%.*]] = unchecked_ownership_conversion [[REG5]], @guaranteed to @unowned
+// CHECK:   [[REG7:%.*]] = unchecked_ownership_conversion [[REG6]], @unowned to @guaranteed
+// CHECK:   end_borrow [[REG3]]
+// CHECK:   return [[REG7]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV9nested_k1AA5KlassCvz : $@convention(method) <T> (@inout GenWrapper<T>) -> @guaranteed_addr Klass {
+// CHECK:bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = struct_element_addr [[REG0]], #GenWrapper._s
+// CHECK:  [[REG3:%.*]] = function_ref @$s15borrow_accessor1SV1kAA5KlassCvz : $@convention(method) (@inout S) -> @guaranteed_addr Klass
+// CHECK:  [[REG4:%.*]] = apply [[REG3]]([[REG2]]) : $@convention(method) (@inout S) -> @guaranteed_addr Klass
+// CHECK:  return [[REG4]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV9nested_k2AA5KlassCvb : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = function_ref @$s15borrow_accessor10GenWrapperV1sAA1SVvb : $@convention(method) <τ_0_0> (@in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed S
+// CHECK:   [[REG3:%.*]] = apply [[REG2]]<T>([[REG0]]) : $@convention(method) <τ_0_0> (@in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed S
+// CHECK:   [[REG4:%.*]] = function_ref @$s15borrow_accessor1SV1kAA5KlassCvb : $@convention(method) (@guaranteed S) -> @guaranteed Klass
+// CHECK:   [[REG5:%.*]] = apply [[REG4]]([[REG3]]) : $@convention(method) (@guaranteed S) -> @guaranteed Klass
+// CHECK:   return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV9nested_k2AA5KlassCvz : $@convention(method) <T> (@inout GenWrapper<T>) -> @guaranteed_addr Klass {
+// CHECK:bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = function_ref @$s15borrow_accessor10GenWrapperV1sAA1SVvz : $@convention(method) <τ_0_0> (@inout GenWrapper<τ_0_0>) -> @guaranteed_addr S
+// CHECK:  [[REG3:%.*]] = apply [[REG2]]<T>([[REG0]]) : $@convention(method) <τ_0_0> (@inout GenWrapper<τ_0_0>) -> @guaranteed_addr S
+// CHECK:  [[REG4:%.*]] = function_ref @$s15borrow_accessor1SV1kAA5KlassCvz : $@convention(method) (@inout S) -> @guaranteed_addr Klass
+// CHECK:  [[REG5:%.*]] = apply [[REG4]]([[REG3]]) : $@convention(method) (@inout S) -> @guaranteed_addr Klass
+// CHECK:  return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperVyxSicib : $@convention(method) <T> (Int, @in_guaranteed GenWrapper<T>) -> @guaranteed_addr T {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*GenWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "index", argno 1
+// CHECK:   debug_value [[REG1]], let, name "self", argno 2, expr op_deref
+// CHECK:   [[REG4:%.*]] = struct_element_addr [[REG1]], #GenWrapper._prop
+// CHECK:   return [[REG4]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperVyxSiciz : $@convention(method) <T> (Int, @inout GenWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*GenWrapper<T>):
+// CHECK:  debug_value [[REG0]], let, name "index", argno 1
+// CHECK:  debug_value [[REG1]], var, name "self", argno 2, expr op_deref
+// CHECK:  [[REG4:%.*]] = struct_element_addr [[REG1]], #GenWrapper._prop
+// CHECK:  return [[REG4]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV16nested_subscriptxvb : $@convention(method) <T> (@in_guaranteed GenWrapper<T>) -> @guaranteed_addr T {
+// CHECK: bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = integer_literal $Builtin.IntLiteral, 0
+// CHECK:   [[REG3:%.*]] = metatype $@thin Int.Type
+// CHECK:   [[REG4:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG5:%.*]] = apply [[REG4]]([[REG2]], [[REG3]]) : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG6:%.*]] = function_ref @$s15borrow_accessor10GenWrapperVyxSicib : $@convention(method) <τ_0_0> (Int, @in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   [[REG7:%.*]] = apply [[REG6]]<T>([[REG5]], [[REG0]]) : $@convention(method) <τ_0_0> (Int, @in_guaranteed GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   return [[REG7]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor10GenWrapperV16nested_subscriptxvz : $@convention(method) <T> (@inout GenWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $*GenWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = integer_literal $Builtin.IntLiteral, 0
+// CHECK:  [[REG3:%.*]] = metatype $@thin Int.Type
+// CHECK:  [[REG4:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:  [[REG5:%.*]] = apply [[REG4]]([[REG2]], [[REG3]]) : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:  [[REG6:%.*]] = function_ref @$s15borrow_accessor10GenWrapperVyxSiciz : $@convention(method) <τ_0_0> (Int, @inout GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG7:%.*]] = apply [[REG6]]<T>([[REG5]], [[REG0]]) : $@convention(method) <τ_0_0> (Int, @inout GenWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  return [[REG7]]
+// CHECK: }
+
+// CHECK: sil [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE4propxvb : $@convention(method) <T where T : ~Copyable> (@in_guaranteed GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK: bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._prop
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// CHECK: sil [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE4propxvz : $@convention(method) <T where T : ~Copyable> (@inout GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG0]]
+// CHECK:  [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._prop
+// CHECK:  return [[REG3]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE2ncAA2NCVvb : $@convention(method) <T where T : ~Copyable> (@in_guaranteed GenNCWrapper<T>) -> @guaranteed NC {
+// CHECK: bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._nc
+// CHECK:   [[REG4:%.*]] = load_borrow [[REG3]]
+// CHECK:   [[REG5:%.*]] = unchecked_ownership_conversion [[REG4]], @guaranteed to @unowned
+// CHECK:   [[REG6:%.*]] = unchecked_ownership_conversion [[REG5]], @unowned to @guaranteed
+// CHECK:   end_borrow [[REG4]]
+// CHECK:   return [[REG6]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE2ncAA2NCVvz : $@convention(method) <T where T : ~Copyable> (@inout GenNCWrapper<T>) -> @guaranteed_addr NC {
+// CHECK:bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG0]]
+// CHECK:  [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._nc
+// CHECK:  return [[REG3]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE3ncwAA0D0Vvb : $@convention(method) <T where T : ~Copyable> (@in_guaranteed GenNCWrapper<T>) -> @guaranteed NCWrapper {
+// CHECK: bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._ncw
+// CHECK:   [[REG4:%.*]] = load_borrow [[REG3]]
+// CHECK:   [[REG5:%.*]] = unchecked_ownership_conversion [[REG4]], @guaranteed to @unowned
+// CHECK:   [[REG6:%.*]] = unchecked_ownership_conversion [[REG5]], @unowned to @guaranteed
+// CHECK:   end_borrow [[REG4]]
+// CHECK:   return [[REG6]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE3ncwAA0D0Vvz : $@convention(method) <T where T : ~Copyable> (@inout GenNCWrapper<T>) -> @guaranteed_addr NCWrapper {
+// CHECK:bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG0]]
+// CHECK:  [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._ncw
+// CHECK:  return [[REG3]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE12nested_prop1xvb : $@convention(method) <T where T : ~Copyable> (@in_guaranteed GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK: bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._w
+// CHECK:   [[REG4:%.*]] = function_ref @$s15borrow_accessor15SimpleNCWrapperVAARi_zrlE4propxvb : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@in_guaranteed SimpleNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   [[REG5:%.*]] = apply [[REG4]]<T>([[REG3]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@in_guaranteed SimpleNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   [[REG6:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG5]]
+// CHECK:   return [[REG6]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE12nested_prop1xvz : $@convention(method) <T where T : ~Copyable> (@inout GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG0]]
+// CHECK:  [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._w
+// CHECK:  [[REG4:%.*]] = function_ref @$s15borrow_accessor15SimpleNCWrapperVAARi_zrlE4propxvz : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@inout SimpleNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG5:%.*]] = apply [[REG4]]<T>([[REG3]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@inout SimpleNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG6:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG5]]
+// CHECK:  return [[REG6]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE12nested_prop2xvb : $@convention(method) <T where T : ~Copyable> (@in_guaranteed GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:  [[REG3:%.*]] = function_ref @$s15borrow_accessor12GenNCWrapperVAARi_zrlE4propxvb : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@in_guaranteed GenNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG4:%.*]] = apply [[REG3]]<T>([[REG2]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@in_guaranteed GenNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG5:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG4]]
+// CHECK:  return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE12nested_prop2xvz : $@convention(method) <T where T : ~Copyable> (@inout GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG0]]
+// CHECK:  [[REG3:%.*]] = function_ref @$s15borrow_accessor12GenNCWrapperVAARi_zrlE4propxvz : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@inout GenNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG4:%.*]] = apply [[REG3]]<T>([[REG2]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@inout GenNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG5:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG4]]
+// CHECK:  return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE10nested_nc1AA2NCVvb : $@convention(method) <T where T : ~Copyable> (@in_guaranteed GenNCWrapper<T>) -> @guaranteed NC {
+// CHECK: bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._ncw
+// CHECK:   [[REG4:%.*]] = load_borrow [[REG3]]
+// CHECK:   [[REG5:%.*]] = function_ref @$s15borrow_accessor9NCWrapperV2ncAA2NCVvb : $@convention(method) (@guaranteed NCWrapper) -> @guaranteed NC
+// CHECK:   [[REG6:%.*]] = apply [[REG5]]([[REG4]]) : $@convention(method) (@guaranteed NCWrapper) -> @guaranteed NC
+// CHECK:   [[REG7:%.*]] = unchecked_ownership_conversion [[REG6]], @guaranteed to @unowned
+// CHECK:   [[REG8:%.*]] = unchecked_ownership_conversion [[REG7]], @unowned to @guaranteed
+// CHECK:   [[REG9:%.*]] = copy_value [[REG8]]
+// CHECK:   [[REG10:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG9]]
+// CHECK:   [[REG11:%.*]] = begin_borrow [[REG10]]
+// CHECK:   end_borrow [[REG4]]
+// CHECK:   end_borrow [[REG11]]
+// CHECK:   destroy_value [[REG10]]
+// CHECK:   return [[REG8]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE10nested_nc1AA2NCVvz : $@convention(method) <T where T : ~Copyable> (@inout GenNCWrapper<T>) -> @guaranteed_addr NC {
+// CHECK:bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG0]]
+// CHECK:  [[REG3:%.*]] = struct_element_addr [[REG2]], #GenNCWrapper._ncw
+// CHECK:  [[REG4:%.*]] = function_ref @$s15borrow_accessor9NCWrapperV2ncAA2NCVvz : $@convention(method) (@inout NCWrapper) -> @guaranteed_addr NC
+// CHECK:  [[REG5:%.*]] = apply [[REG4]]([[REG3]]) : $@convention(method) (@inout NCWrapper) -> @guaranteed_addr NC
+// CHECK:  [[REG6:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG5]]
+// CHECK:  return [[REG6]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE10nested_nc2AA2NCVvb : $@convention(method) <T where T : ~Copyable> (@in_guaranteed GenNCWrapper<T>) -> @guaranteed NC {
+// CHECK: bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = function_ref @$s15borrow_accessor12GenNCWrapperVAARi_zrlE3ncwAA0D0Vvb : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@in_guaranteed GenNCWrapper<τ_0_0>) -> @guaranteed NCWrapper
+// CHECK:   [[REG4:%.*]] = apply [[REG3]]<T>([[REG2]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@in_guaranteed GenNCWrapper<τ_0_0>) -> @guaranteed NCWrapper
+// CHECK:   [[REG5:%.*]] = copy_value [[REG4]]
+// CHECK:   [[REG6:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG5]]
+// CHECK:   [[REG7:%.*]] = begin_borrow [[REG6]]
+// CHECK:   [[REG8:%.*]] = function_ref @$s15borrow_accessor9NCWrapperV2ncAA2NCVvb : $@convention(method) (@guaranteed NCWrapper) -> @guaranteed NC
+// CHECK:   [[REG9:%.*]] = apply [[REG8]]([[REG4]]) : $@convention(method) (@guaranteed NCWrapper) -> @guaranteed NC
+// CHECK:   [[REG10:%.*]] = copy_value [[REG9]]
+// CHECK:   [[REG11:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG10]]
+// CHECK:   [[REG12:%.*]] = begin_borrow [[REG11]]
+// CHECK:   end_borrow [[REG12]]
+// CHECK:   destroy_value [[REG11]]
+// CHECK:   end_borrow [[REG7]]
+// CHECK:   destroy_value [[REG6]]
+// CHECK:   return [[REG9]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE10nested_nc2AA2NCVvz : $@convention(method) <T where T : ~Copyable> (@inout GenNCWrapper<T>) -> @guaranteed_addr NC {
+// CHECK:bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG0]]
+// CHECK:  [[REG3:%.*]] = function_ref @$s15borrow_accessor12GenNCWrapperVAARi_zrlE3ncwAA0D0Vvz : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@inout GenNCWrapper<τ_0_0>) -> @guaranteed_addr NCWrapper
+// CHECK:  [[REG4:%.*]] = apply [[REG3]]<T>([[REG2]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (@inout GenNCWrapper<τ_0_0>) -> @guaranteed_addr NCWrapper
+// CHECK:  [[REG5:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG4]]
+// CHECK:  [[REG6:%.*]] = function_ref @$s15borrow_accessor9NCWrapperV2ncAA2NCVvz : $@convention(method) (@inout NCWrapper) -> @guaranteed_addr NC
+// CHECK:  [[REG7:%.*]] = apply [[REG6]]([[REG5]]) : $@convention(method) (@inout NCWrapper) -> @guaranteed_addr NC
+// CHECK:  [[REG8:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG7]]
+// CHECK:  return [[REG8]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlEyxSicib : $@convention(method) <T where T : ~Copyable> (Int, @in_guaranteed GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*GenNCWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "index", argno 1
+// CHECK:   debug_value [[REG1]], let, name "self", argno 2, expr op_deref
+// CHECK:   [[REG4:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG1]]
+// CHECK:   [[REG5:%.*]] = struct_element_addr [[REG4]], #GenNCWrapper._prop
+// CHECK:   return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlEyxSiciz : $@convention(method) <T where T : ~Copyable> (Int, @inout GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], let, name "index", argno 1
+// CHECK:  debug_value [[REG1]], var, name "self", argno 2, expr op_deref
+// CHECK:  [[REG4:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG1]]
+// CHECK:  [[REG5:%.*]] = struct_element_addr [[REG4]], #GenNCWrapper._prop
+// CHECK:  return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE16nested_subscriptxvb : $@convention(method) <T where T : ~Copyable> (@in_guaranteed GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK: bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = integer_literal $Builtin.IntLiteral, 0
+// CHECK:   [[REG4:%.*]] = metatype $@thin Int.Type
+// CHECK:   [[REG5:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG6:%.*]] = apply [[REG5]]([[REG3]], [[REG4]]) : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG7:%.*]] = function_ref @$s15borrow_accessor12GenNCWrapperVAARi_zrlEyxSicib : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (Int, @in_guaranteed GenNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   [[REG8:%.*]] = apply [[REG7]]<T>([[REG6]], [[REG2]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (Int, @in_guaranteed GenNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:   [[REG9:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG8]]
+// CHECK:   return [[REG9]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s15borrow_accessor12GenNCWrapperVAARi_zrlE16nested_subscriptxvz : $@convention(method) <T where T : ~Copyable> (@inout GenNCWrapper<T>) -> @guaranteed_addr T {
+// CHECK:bb0([[REG0:%.*]] : $*GenNCWrapper<T>):
+// CHECK:  debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:  [[REG2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG0]]
+// CHECK:  [[REG3:%.*]] = integer_literal $Builtin.IntLiteral, 0
+// CHECK:  [[REG4:%.*]] = metatype $@thin Int.Type
+// CHECK:  [[REG5:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:  [[REG6:%.*]] = apply [[REG5]]([[REG3]], [[REG4]]) : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:  [[REG7:%.*]] = function_ref @$s15borrow_accessor12GenNCWrapperVAARi_zrlEyxSiciz : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (Int, @inout GenNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG8:%.*]] = apply [[REG7]]<T>([[REG6]], [[REG2]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (Int, @inout GenNCWrapper<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK:  [[REG9:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG8]]
+// CHECK:  return [[REG9]]
+// CHECK: }
+
diff --git a/test/SILGen/borrow_accessor_container.swift b/test/SILGen/borrow_accessor_container.swift
new file mode 100644
index 0000000000000..02a1fed16e061
--- /dev/null
+++ b/test/SILGen/borrow_accessor_container.swift
@@ -0,0 +1,377 @@
+// RUN:%target-swift-frontend -emit-silgen %s -verify  -enable-experimental-feature BorrowAndMutateAccessors | %FileCheck %s
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+
+public struct Container<Element: ~Copyable >: ~Copyable {
+  var _storage: UnsafeMutableBufferPointer<Element>
+  var _count: Int
+
+  var first: Element {
+    @_unsafeSelfDependentResult
+    borrow {
+      return _storage.baseAddress.unsafelyUnwrapped.pointee
+    }
+    @_unsafeSelfDependentResult
+    mutate {
+      return &_storage.baseAddress.unsafelyUnwrapped.pointee
+    }
+  }
+
+  public subscript(index: Int) -> Element {
+    @_unsafeSelfDependentResult
+    borrow {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return _storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee
+    }
+    @_unsafeSelfDependentResult
+    mutate {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return &_storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee
+    }
+  }
+}
+
+extension Container: Copyable where Element: Copyable {}
+
+// CHECK: sil hidden [ossa] @$s25borrow_accessor_container9ContainerVAARi_zrlE5firstxvb : $@convention(method) <Element where Element : ~Copyable> (@guaranteed Container<Element>) -> @guaranteed_addr Element {
+// CHECK: bb0([[REG0:%.*]] : @guaranteed $Container<Element>):
+// CHECK:   [[REG1:%.*]] = copy_value [[REG0]]
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG1]]
+// CHECK:   debug_value [[REG2]], let, name "self", argno 1
+// CHECK:   [[REG4:%.*]] = begin_borrow [[REG2]]
+// CHECK:   [[REG5:%.*]] = struct_extract [[REG0]], #Container._storage
+// CHECK:   [[REG6:%.*]] = alloc_stack $Optional<UnsafeMutablePointer<Element>>
+// CHECK:   [[REG7:%.*]] = function_ref @$sSr11baseAddressSpyxGSgvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG8:%.*]] = apply [[REG7]]<Element>([[REG5]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   store [[REG8]] to [trivial] [[REG6]]
+// CHECK:   [[REG10:%.*]] = alloc_stack $UnsafeMutablePointer<Element>
+// CHECK:   [[REG11:%.*]] = function_ref @$sSq17unsafelyUnwrappedxvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG12:%.*]] = apply [[REG11]]<UnsafeMutablePointer<Element>>([[REG10]], [[REG6]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG13:%.*]] = load [trivial] [[REG10]]
+// CHECK:   [[REG14:%.*]] = function_ref @$sSpsRi_zrlE7pointeexvlu : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafePointer<τ_0_0>
+// CHECK:   [[REG15:%.*]] = apply [[REG14]]<Element>([[REG13]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafePointer<τ_0_0>
+// CHECK:   [[REG16:%.*]] = struct_extract [[REG15]], #UnsafePointer._rawValue
+// CHECK:   [[REG17:%.*]] = pointer_to_address [[REG16]] to [strict] $*Element
+// CHECK:   [[REG18:%.*]] = mark_dependence [unresolved] [[REG17]] on [[REG13]]
+// CHECK:   [[REG19:%.*]] = begin_access [read] [unsafe] [[REG18]]
+// CHECK:   [[REG20:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG19]]
+// CHECK:   end_access [[REG19]]
+// CHECK:   dealloc_stack [[REG10]]
+// CHECK:   dealloc_stack [[REG6]]
+// CHECK:   end_borrow [[REG4]]
+// CHECK:   destroy_value [[REG2]]
+// CHECK:   return [[REG20]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s25borrow_accessor_container9ContainerVAARi_zrlE5firstxvz : $@convention(method) <Element where Element : ~Copyable> (@inout Container<Element>) -> @guaranteed_addr Element {
+// CHECK: bb0([[REG0:%.*]] : $*Container<Element>):
+// CHECK:   debug_value [[REG0]], var, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG0]]
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG2]], #Container._storage
+// CHECK:   [[REG4:%.*]] = load [trivial] [[REG3]]
+// CHECK:   [[REG5:%.*]] = alloc_stack $Optional<UnsafeMutablePointer<Element>>
+// CHECK:   [[REG6:%.*]] = function_ref @$sSr11baseAddressSpyxGSgvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG7:%.*]] = apply [[REG6]]<Element>([[REG4]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   store [[REG7]] to [trivial] [[REG5]]
+// CHECK:   [[REG9:%.*]] = alloc_stack $UnsafeMutablePointer<Element>
+// CHECK:   [[REG10:%.*]] = function_ref @$sSq17unsafelyUnwrappedxvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG11:%.*]] = apply [[REG10]]<UnsafeMutablePointer<Element>>([[REG9]], [[REG5]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG12:%.*]] = load [trivial] [[REG9]]
+// CHECK:   [[REG13:%.*]] = function_ref @$sSpsRi_zrlE7pointeexvau : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
+// CHECK:   [[REG14:%.*]] = apply [[REG13]]<Element>([[REG12]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
+// CHECK:   [[REG15:%.*]] = struct_extract [[REG14]], #UnsafeMutablePointer._rawValue
+// CHECK:   [[REG16:%.*]] = pointer_to_address [[REG15]] to [strict] $*Element
+// CHECK:   [[REG17:%.*]] = mark_dependence [unresolved] [[REG16]] on [[REG12]]
+// CHECK:   [[REG18:%.*]] = begin_access [modify] [unsafe] [[REG17]]
+// CHECK:   [[REG19:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG18]]
+// CHECK:   end_access [[REG18]]
+// CHECK:   dealloc_stack [[REG9]]
+// CHECK:   dealloc_stack [[REG5]]
+// CHECK:   return [[REG19]]
+// CHECK: }
+
+// CHECK: sil [ossa] @$s25borrow_accessor_container9ContainerVAARi_zrlEyxSicib : $@convention(method) <Element where Element : ~Copyable> (Int, @guaranteed Container<Element>) -> @guaranteed_addr Element {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : @guaranteed $Container<Element>):
+// CHECK:   [[REG3:%.*]] = copy_value [[REG1]]
+// CHECK:   [[REG4:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG3]]
+// CHECK:   [[REG6:%.*]] = alloc_stack $UnsafeMutablePointer<Element>
+// CHECK:   [[REG7:%.*]] = begin_borrow [[REG4]]
+// CHECK:   [[REG8:%.*]] = struct_extract [[REG7]], #Container._storage
+// CHECK:   [[REG9:%.*]] = function_ref @$sSr11baseAddressSpyxGSgvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG10:%.*]] = apply [[REG9]]<Element>([[REG8]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG11:%.*]] = alloc_stack $Optional<UnsafeMutablePointer<Element>>
+// CHECK:   store [[REG10]] to [trivial] [[REG11]]
+// CHECK:   [[REG13:%.*]] = alloc_stack $UnsafeMutablePointer<Element>
+// CHECK:   [[REG14:%.*]] = function_ref @$sSq17unsafelyUnwrappedxvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG15:%.*]] = apply [[REG14]]<UnsafeMutablePointer<Element>>([[REG13]], [[REG11]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG16:%.*]] = load [trivial] [[REG13]]
+// CHECK:   [[REG17:%.*]] = alloc_stack $UnsafeMutablePointer<Element>
+// CHECK:   store [[REG16]] to [trivial] [[REG17]]
+// CHECK:   [[REG19:%.*]] = function_ref @$ss8_PointerPsE8advanced2byxSi_tF : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   [[REG20:%.*]] = apply [[REG19]]<UnsafeMutablePointer<Element>>([[REG6]], [[REG0]], [[REG17]]) : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   dealloc_stack [[REG17]]
+// CHECK:   dealloc_stack [[REG13]]
+// CHECK:   dealloc_stack [[REG11]]
+// CHECK:   end_borrow [[REG7]]
+// CHECK:   [[REG25:%.*]] = load [trivial] [[REG6]]
+// CHECK:   [[REG26:%.*]] = function_ref @$sSpsRi_zrlE7pointeexvlu : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafePointer<τ_0_0>
+// CHECK:   [[REG27:%.*]] = apply [[REG26]]<Element>([[REG25]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafePointer<τ_0_0>
+// CHECK:   [[REG28:%.*]] = struct_extract [[REG27]], #UnsafePointer._rawValue
+// CHECK:   [[REG29:%.*]] = pointer_to_address [[REG28]] to [strict] $*Element
+// CHECK:   [[REG30:%.*]] = mark_dependence [unresolved] [[REG29]] on [[REG25]]
+// CHECK:   [[REG31:%.*]] = begin_access [read] [unsafe] [[REG30]]
+// CHECK:   [[REG32:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG31]]
+// CHECK:   end_access [[REG31]]
+// CHECK:   dealloc_stack [[REG6]]
+// CHECK:   destroy_value [[REG4]]
+// CHECK:   return [[REG32]]
+// CHECK: }
+
+// CHECK: sil [ossa] @$s25borrow_accessor_container9ContainerVAARi_zrlEyxSiciz : $@convention(method) <Element where Element : ~Copyable> (Int, @inout Container<Element>) -> @guaranteed_addr Element {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*Container<Element>):
+// CHECK:   debug_value [[REG0]], let, name "index", argno 1
+// CHECK:   debug_value [[REG1]], var, name "self", argno 2, expr op_deref
+// CHECK:   [[REG4:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG1]]
+// CHECK:   [[REG5:%.*]] = alloc_stack $UnsafeMutablePointer<Element>
+// CHECK:   [[REG6:%.*]] = begin_access [read] [unknown] [[REG4]]
+// CHECK:   [[REG7:%.*]] = struct_element_addr [[REG6]], #Container._storage
+// CHECK:   [[REG8:%.*]] = load [trivial] [[REG7]]
+// CHECK:   end_access [[REG6]]
+// CHECK:   [[REG10:%.*]] = function_ref @$sSr11baseAddressSpyxGSgvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG11:%.*]] = apply [[REG10]]<Element>([[REG8]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG12:%.*]] = alloc_stack $Optional<UnsafeMutablePointer<Element>>
+// CHECK:   store [[REG11]] to [trivial] [[REG12]]
+// CHECK:   [[REG14:%.*]] = alloc_stack $UnsafeMutablePointer<Element>
+// CHECK:   [[REG15:%.*]] = function_ref @$sSq17unsafelyUnwrappedxvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG16:%.*]] = apply [[REG15]]<UnsafeMutablePointer<Element>>([[REG14]], [[REG12]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG17:%.*]] = load [trivial] [[REG14]]
+// CHECK:   [[REG18:%.*]] = alloc_stack $UnsafeMutablePointer<Element>
+// CHECK:   store [[REG17]] to [trivial] [[REG18]]
+// CHECK:   [[REG20:%.*]] = function_ref @$ss8_PointerPsE8advanced2byxSi_tF : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   [[REG21:%.*]] = apply [[REG20]]<UnsafeMutablePointer<Element>>([[REG5]], [[REG0]], [[REG18]]) : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   dealloc_stack [[REG18]]
+// CHECK:   dealloc_stack [[REG14]]
+// CHECK:   dealloc_stack [[REG12]]
+// CHECK:   [[REG25:%.*]] = load [trivial] [[REG5]]
+// CHECK:   [[REG26:%.*]] = function_ref @$sSpsRi_zrlE7pointeexvau : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
+// CHECK:   [[REG27:%.*]] = apply [[REG26]]<Element>([[REG25]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
+// CHECK:   [[REG28:%.*]] = struct_extract [[REG27]], #UnsafeMutablePointer._rawValue
+// CHECK:   [[REG29:%.*]] = pointer_to_address [[REG28]] to [strict] $*Element
+// CHECK:   [[REG30:%.*]] = mark_dependence [unresolved] [[REG29]] on [[REG25]]
+// CHECK:   [[REG31:%.*]] = begin_access [modify] [unsafe] [[REG30]]
+// CHECK:   [[REG32:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG31]]
+// CHECK:   end_access [[REG31]]
+// CHECK:   dealloc_stack [[REG5]]
+// CHECK:   return [[REG32]]
+// CHECK: }
+
+public class Klass {}
+
+public struct S {
+  var _k: Klass
+}
+
+public struct CopyableContainer {
+  var _storage: UnsafeMutableBufferPointer<S>
+  var _count: Int
+
+  var first: S {
+    @_unsafeSelfDependentResult
+    borrow {
+      return _storage.baseAddress.unsafelyUnwrapped.pointee
+    }
+  }
+
+  public subscript(index: Int) -> Klass {
+    @_unsafeSelfDependentResult
+    borrow {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return _storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee._k
+    }
+    @_unsafeSelfDependentResult
+    mutate {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return &_storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee._k
+    }
+  }
+}
+
+// CHECK: sil [ossa] @$s25borrow_accessor_container17CopyableContainerVyAA5KlassCSicib : $@convention(method) (Int, CopyableContainer) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $CopyableContainer):
+// CHECK:   [[REG4:%.*]] = alloc_stack $UnsafeMutablePointer<S>
+// CHECK:   [[REG5:%.*]] = struct_extract [[REG1]], #CopyableContainer._storage
+// CHECK:   [[REG6:%.*]] = function_ref @$sSr11baseAddressSpyxGSgvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG7:%.*]] = apply [[REG6]]<S>([[REG5]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG8:%.*]] = alloc_stack $Optional<UnsafeMutablePointer<S>>
+// CHECK:   store [[REG7]] to [trivial] [[REG8]]
+// CHECK:   [[REG10:%.*]] = alloc_stack $UnsafeMutablePointer<S>
+// CHECK:   [[REG11:%.*]] = function_ref @$sSq17unsafelyUnwrappedxvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG12:%.*]] = apply [[REG11]]<UnsafeMutablePointer<S>>([[REG10]], [[REG8]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG13:%.*]] = load [trivial] [[REG10]]
+// CHECK:   [[REG14:%.*]] = alloc_stack $UnsafeMutablePointer<S>
+// CHECK:   store [[REG13]] to [trivial] [[REG14]]
+// CHECK:   [[REG16:%.*]] = function_ref @$ss8_PointerPsE8advanced2byxSi_tF : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   [[REG17:%.*]] = apply [[REG16]]<UnsafeMutablePointer<S>>([[REG4]], [[REG0]], [[REG14]]) : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   dealloc_stack [[REG14]]
+// CHECK:   dealloc_stack [[REG10]]
+// CHECK:   dealloc_stack [[REG8]]
+// CHECK:   [[REG21:%.*]] = load [trivial] [[REG4]]
+// CHECK:   [[REG22:%.*]] = function_ref @$sSpsRi_zrlE7pointeexvlu : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafePointer<τ_0_0>
+// CHECK:   [[REG23:%.*]] = apply [[REG22]]<S>([[REG21]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafePointer<τ_0_0>
+// CHECK:   [[REG24:%.*]] = struct_extract [[REG23]], #UnsafePointer._rawValue
+// CHECK:   [[REG25:%.*]] = pointer_to_address [[REG24]] to [strict] $*S
+// CHECK:   [[REG26:%.*]] = mark_dependence [unresolved] [[REG25]] on [[REG21]]
+// CHECK:   [[REG27:%.*]] = begin_access [read] [unsafe] [[REG26]]
+// CHECK:   [[REG28:%.*]] = struct_element_addr [[REG27]], #S._k
+// CHECK:   [[REG29:%.*]] = load_borrow [[REG28]]
+// CHECK:   [[REG31:%.*]] = unchecked_ownership_conversion [[REG29]], @guaranteed to @unowned
+// CHECK:   [[REG32:%.*]] = unchecked_ownership_conversion [[REG31]], @unowned to @guaranteed
+// CHECK:   end_access [[REG27]]
+// CHECK:   end_borrow [[REG29]]
+// CHECK:   dealloc_stack [[REG4]]
+// CHECK:   return [[REG32]]
+// CHECK: }
+
+// CHECK: sil [ossa] @$s25borrow_accessor_container17CopyableContainerVyAA5KlassCSiciz : $@convention(method) (Int, @inout CopyableContainer) -> @guaranteed_addr Klass {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*CopyableContainer):
+// CHECK:   debug_value [[REG0]], let, name "index", argno 1
+// CHECK:   debug_value [[REG1]], var, name "self", argno 2, expr op_deref
+// CHECK:   [[REG4:%.*]] = alloc_stack $UnsafeMutablePointer<S>
+// CHECK:   [[REG5:%.*]] = begin_access [read] [unknown] [[REG1]]
+// CHECK:   [[REG6:%.*]] = struct_element_addr [[REG5]], #CopyableContainer._storage
+// CHECK:   [[REG7:%.*]] = load [trivial] [[REG6]]
+// CHECK:   end_access [[REG5]]
+// CHECK:   [[REG9:%.*]] = function_ref @$sSr11baseAddressSpyxGSgvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG10:%.*]] = apply [[REG9]]<S>([[REG7]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG11:%.*]] = alloc_stack $Optional<UnsafeMutablePointer<S>>
+// CHECK:   store [[REG10]] to [trivial] [[REG11]]
+// CHECK:   [[REG13:%.*]] = alloc_stack $UnsafeMutablePointer<S>
+// CHECK:   [[REG14:%.*]] = function_ref @$sSq17unsafelyUnwrappedxvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG15:%.*]] = apply [[REG14]]<UnsafeMutablePointer<S>>([[REG13]], [[REG11]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG16:%.*]] = load [trivial] [[REG13]]
+// CHECK:   [[REG17:%.*]] = alloc_stack $UnsafeMutablePointer<S>
+// CHECK:   store [[REG16]] to [trivial] [[REG17]]
+// CHECK:   [[REG19:%.*]] = function_ref @$ss8_PointerPsE8advanced2byxSi_tF : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   [[REG20:%.*]] = apply [[REG19]]<UnsafeMutablePointer<S>>([[REG4]], [[REG0]], [[REG17]]) : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   dealloc_stack [[REG17]]
+// CHECK:   dealloc_stack [[REG13]]
+// CHECK:   dealloc_stack [[REG11]]
+// CHECK:   [[REG24:%.*]] = load [trivial] [[REG4]]
+// CHECK:   [[REG25:%.*]] = function_ref @$sSpsRi_zrlE7pointeexvau : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
+// CHECK:   [[REG26:%.*]] = apply [[REG25]]<S>([[REG24]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
+// CHECK:   [[REG27:%.*]] = struct_extract [[REG26]], #UnsafeMutablePointer._rawValue
+// CHECK:   [[REG28:%.*]] = pointer_to_address [[REG27]] to [strict] $*S
+// CHECK:   [[REG29:%.*]] = mark_dependence [unresolved] [[REG28]] on [[REG24]]
+// CHECK:   [[REG30:%.*]] = begin_access [modify] [unsafe] [[REG29]]
+// CHECK:   [[REG31:%.*]] = struct_element_addr [[REG30]], #S._k
+// CHECK:   end_access [[REG30]]
+// CHECK:   dealloc_stack [[REG4]]
+// CHECK:   return [[REG31]]
+// CHECK: }
+
+public struct NC : ~Copyable {}
+
+public struct NonCopyableContainer : ~Copyable {
+  var _storage: UnsafeMutableBufferPointer<NC>
+  var _count: Int
+
+  var first: NC {
+    @_unsafeSelfDependentResult
+    borrow {
+      return _storage.baseAddress.unsafelyUnwrapped.pointee
+    }
+  }
+
+  public subscript(index: Int) -> NC {
+    @_unsafeSelfDependentResult
+    borrow {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return _storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee
+    }
+    @_unsafeSelfDependentResult
+    mutate {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return &_storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee
+    }
+  }
+}
+
+// CHECK: sil [ossa] @$s25borrow_accessor_container20NonCopyableContainerVyAA2NCVSicib : $@convention(method) (Int, @guaranteed NonCopyableContainer) -> @guaranteed NC {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : @guaranteed $NonCopyableContainer):
+// CHECK:   [[REG3:%.*]] = copy_value [[REG1]]
+// CHECK:   [[REG4:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG3]]
+// CHECK:   debug_value [[REG4]], let, name "self", argno 2
+// CHECK:   [[REG6:%.*]] = alloc_stack $UnsafeMutablePointer<NC>
+// CHECK:   [[REG7:%.*]] = begin_borrow [[REG4]]
+// CHECK:   [[REG8:%.*]] = struct_extract [[REG7]], #NonCopyableContainer._storage
+// CHECK:   [[REG9:%.*]] = function_ref @$sSr11baseAddressSpyxGSgvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG10:%.*]] = apply [[REG9]]<NC>([[REG8]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG11:%.*]] = alloc_stack $Optional<UnsafeMutablePointer<NC>>
+// CHECK:   store [[REG10]] to [trivial] [[REG11]]
+// CHECK:   [[REG13:%.*]] = alloc_stack $UnsafeMutablePointer<NC>
+// CHECK:   [[REG14:%.*]] = function_ref @$sSq17unsafelyUnwrappedxvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG15:%.*]] = apply [[REG14]]<UnsafeMutablePointer<NC>>([[REG13]], [[REG11]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG16:%.*]] = load [trivial] [[REG13]]
+// CHECK:   [[REG17:%.*]] = alloc_stack $UnsafeMutablePointer<NC>
+// CHECK:   store [[REG16]] to [trivial] [[REG17]]
+// CHECK:   [[REG19:%.*]] = function_ref @$ss8_PointerPsE8advanced2byxSi_tF : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   [[REG20:%.*]] = apply [[REG19]]<UnsafeMutablePointer<NC>>([[REG6]], [[REG0]], [[REG17]]) : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   dealloc_stack [[REG17]]
+// CHECK:   dealloc_stack [[REG13]]
+// CHECK:   dealloc_stack [[REG11]]
+// CHECK:   end_borrow [[REG7]]
+// CHECK:   [[REG25:%.*]] = load [trivial] [[REG6]]
+// CHECK:   [[REG26:%.*]] = function_ref @$sSpsRi_zrlE7pointeexvlu : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafePointer<τ_0_0>
+// CHECK:   [[REG27:%.*]] = apply [[REG26]]<NC>([[REG25]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafePointer<τ_0_0>
+// CHECK:   [[REG28:%.*]] = struct_extract [[REG27]], #UnsafePointer._rawValue
+// CHECK:   [[REG29:%.*]] = pointer_to_address [[REG28]] to [strict] $*NC
+// CHECK:   [[REG30:%.*]] = mark_dependence [unresolved] [[REG29]] on [[REG25]]
+// CHECK:   [[REG31:%.*]] = begin_access [read] [unsafe] [[REG30]]
+// CHECK:   [[REG32:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG31]]
+// CHECK:   [[REG33:%.*]] = load_borrow [[REG32]]
+// CHECK:   [[REG35:%.*]] = unchecked_ownership_conversion [[REG33]], @guaranteed to @unowned
+// CHECK:   [[REG36:%.*]] = unchecked_ownership_conversion [[REG35]], @unowned to @guaranteed
+// CHECK:   end_access [[REG31]]
+// CHECK:   end_borrow [[REG33]]
+// CHECK:   dealloc_stack [[REG6]]
+// CHECK:   destroy_value [[REG4]]
+// CHECK:   return [[REG36]]
+// CHECK: }
+
+// CHECK: sil [ossa] @$s25borrow_accessor_container20NonCopyableContainerVyAA2NCVSiciz : $@convention(method) (Int, @inout NonCopyableContainer) -> @guaranteed_addr NC {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*NonCopyableContainer):
+// CHECK:   debug_value [[REG0]], let, name "index", argno 1
+// CHECK:   debug_value [[REG1]], var, name "self", argno 2, expr op_deref
+// CHECK:   [[REG4:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG1]]
+// CHECK:   [[REG5:%.*]] = alloc_stack $UnsafeMutablePointer<NC>
+// CHECK:   [[REG6:%.*]] = begin_access [read] [unknown] [[REG4]]
+// CHECK:   [[REG7:%.*]] = struct_element_addr [[REG6]], #NonCopyableContainer._storage
+// CHECK:   [[REG8:%.*]] = load [trivial] [[REG7]]
+// CHECK:   end_access [[REG6]]
+// CHECK:   [[REG10:%.*]] = function_ref @$sSr11baseAddressSpyxGSgvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG11:%.*]] = apply [[REG10]]<NC>([[REG8]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutableBufferPointer<τ_0_0>) -> Optional<UnsafeMutablePointer<τ_0_0>>
+// CHECK:   [[REG12:%.*]] = alloc_stack $Optional<UnsafeMutablePointer<NC>>
+// CHECK:   store [[REG11]] to [trivial] [[REG12]]
+// CHECK:   [[REG14:%.*]] = alloc_stack $UnsafeMutablePointer<NC>
+// CHECK:   [[REG15:%.*]] = function_ref @$sSq17unsafelyUnwrappedxvg : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG16:%.*]] = apply [[REG15]]<UnsafeMutablePointer<NC>>([[REG14]], [[REG12]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed Optional<τ_0_0>) -> @lifetime(copy 0) @out τ_0_0
+// CHECK:   [[REG17:%.*]] = load [trivial] [[REG14]]
+// CHECK:   [[REG18:%.*]] = alloc_stack $UnsafeMutablePointer<NC>
+// CHECK:   store [[REG17]] to [trivial] [[REG18]]
+// CHECK:   [[REG20:%.*]] = function_ref @$ss8_PointerPsE8advanced2byxSi_tF : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   [[REG21:%.*]] = apply [[REG20]]<UnsafeMutablePointer<NC>>([[REG5]], [[REG0]], [[REG18]]) : $@convention(method) <τ_0_0 where τ_0_0 : _Pointer> (Int, @in_guaranteed τ_0_0) -> @out τ_0_0
+// CHECK:   dealloc_stack [[REG18]]
+// CHECK:   dealloc_stack [[REG14]]
+// CHECK:   dealloc_stack [[REG12]]
+// CHECK:   [[REG25:%.*]] = load [trivial] [[REG5]]
+// CHECK:   [[REG26:%.*]] = function_ref @$sSpsRi_zrlE7pointeexvau : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
+// CHECK:   [[REG27:%.*]] = apply [[REG26]]<NC>([[REG25]]) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafeMutablePointer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
+// CHECK:   [[REG28:%.*]] = struct_extract [[REG27]], #UnsafeMutablePointer._rawValue
+// CHECK:   [[REG29:%.*]] = pointer_to_address [[REG28]] to [strict] $*NC
+// CHECK:   [[REG30:%.*]] = mark_dependence [unresolved] [[REG29]] on [[REG25]]
+// CHECK:   [[REG31:%.*]] = begin_access [modify] [unsafe] [[REG30]]
+// CHECK:   [[REG32:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[REG31]]
+// CHECK:   end_access [[REG31]]
+// CHECK:   dealloc_stack [[REG5]]
+// CHECK:   return [[REG32]]
+// CHECK: }
diff --git a/test/SILGen/borrow_accessor_evolution.swift b/test/SILGen/borrow_accessor_evolution.swift
new file mode 100644
index 0000000000000..7e1fbb65ae921
--- /dev/null
+++ b/test/SILGen/borrow_accessor_evolution.swift
@@ -0,0 +1,239 @@
+// RUN:%target-swift-frontend -emit-silgen %s -verify  -enable-experimental-feature BorrowAndMutateAccessors -enable-library-evolution | %FileCheck %s
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+
+public class Klass {}
+
+func getKlass() -> Klass {
+  return Klass()
+}
+
+func use(_ t: Klass) {}
+
+public struct NC : ~Copyable {}
+
+func use(_ t: borrowing NC) {}
+
+public struct S {
+  var _k: Klass
+  var k: Klass {
+    borrow {
+      return _k
+    }
+  }
+}
+
+public struct Wrapper {
+  var _k: Klass
+  var _s: S
+
+  var s: S {
+    borrow {
+      return _s
+    }
+  }
+
+  var k: Klass {
+    borrow {
+      return _k
+    }
+  }
+
+  var nested1: Klass {
+    borrow {
+      return _s.k
+    }
+  }
+
+  var nested2: Klass {
+    borrow {
+      return k
+    }
+  }
+
+  subscript(index: Int) -> Klass {
+    borrow {
+      return _k
+    }
+  }
+
+  var nested_subscript: Klass {
+    borrow {
+      return self[0]
+    }
+  }
+}
+
+public struct NCS: ~Copyable {
+  var _nc: NC
+
+  var nc: NC {
+    borrow {
+      return _nc
+    }
+  }
+}
+
+public struct NCWrapper: ~Copyable {
+  var _nc: NC
+  var _s: NCS
+
+  var nc: NC {
+    borrow {
+      return _nc
+    }
+  }
+  var nested1: NC {
+    borrow {
+      return _s.nc
+    }
+  }
+
+  var nested2: NC {
+    borrow {
+      return nc
+    }
+  }
+
+  subscript(index: Int) -> NC {
+    borrow {
+      return _nc
+    }
+  }
+
+  var nested_subscript: NC {
+    borrow {
+      return self[0]
+    }
+  }
+}
+
+func test() {
+  let w1 = Wrapper(_k: Klass(), _s: S(_k: Klass()))
+  use(w1.k)
+  var k1 = w1.k
+  use(k1)
+  k1 = Klass()
+  use(k1)
+  use(w1.nested1)
+  use(w1.nested2)
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s25borrow_accessor_evolution7WrapperV1sAA1SVvb : $@convention(method) (@in_guaranteed Wrapper) -> @guaranteed_addr S {
+// CHECK: bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #Wrapper._s
+// CHECK:   return [[REG2]]
+// CHECK: }
+
+// CHECK-LABEL: sil hidden [ossa] @$s25borrow_accessor_evolution7WrapperV1kAA5KlassCvb : $@convention(method) (@in_guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #Wrapper._k
+// CHECK:   [[REG3:%.*]] = load_borrow [[REG2]]
+// CHECK:   [[REG4:%.*]] = unchecked_ownership_conversion [[REG3]], @guaranteed to @unowned
+// CHECK:   [[REG5:%.*]] = unchecked_ownership_conversion [[REG4]], @unowned to @guaranteed
+// CHECK:   return [[REG5]]
+// CHECK: }
+
+// CHECK-LABEL: sil hidden [ossa] @$s25borrow_accessor_evolution7WrapperV7nested1AA5KlassCvb : $@convention(method) (@in_guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = struct_element_addr [[REG0]], #Wrapper._s
+// CHECK:   [[REG3:%.*]] = function_ref @$s25borrow_accessor_evolution1SV1kAA5KlassCvb : $@convention(method) (@in_guaranteed S) -> @guaranteed Klass
+// CHECK:   [[REG4:%.*]] = apply [[REG3]]([[REG2]]) : $@convention(method) (@in_guaranteed S) -> @guaranteed Klass
+// CHECK:   return [[REG4]]
+// CHECK: }
+
+// CHECK-LABEL: sil hidden [ossa] @$s25borrow_accessor_evolution7WrapperV7nested2AA5KlassCvb : $@convention(method) (@in_guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = function_ref @$s25borrow_accessor_evolution7WrapperV1kAA5KlassCvb : $@convention(method) (@in_guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   [[REG3:%.*]] = apply [[REG2]]([[REG0]]) : $@convention(method) (@in_guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// CHECK-LABEL: sil hidden [ossa] @$s25borrow_accessor_evolution7WrapperVyAA5KlassCSicib : $@convention(method) (Int, @in_guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "index", argno 1
+// CHECK:   debug_value [[REG1]], let, name "self", argno 2, expr op_deref
+// CHECK:   [[REG4:%.*]] = struct_element_addr [[REG1]], #Wrapper._k
+// CHECK:   [[REG5:%.*]] = load_borrow [[REG4]]
+// CHECK:   [[REG6:%.*]] = unchecked_ownership_conversion [[REG5]], @guaranteed to @unowned
+// CHECK:   [[REG7:%.*]] = unchecked_ownership_conversion [[REG6]], @unowned to @guaranteed
+// CHECK:   end_borrow [[REG5]]
+// CHECK:   return [[REG7]]
+// CHECK: }
+
+// CHECK-LABEL: sil hidden [ossa] @$s25borrow_accessor_evolution7WrapperV16nested_subscriptAA5KlassCvb : $@convention(method) (@in_guaranteed Wrapper) -> @guaranteed Klass {
+// CHECK: bb0([[REG0:%.*]] : $*Wrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = integer_literal $Builtin.IntLiteral, 0
+// CHECK:   [[REG3:%.*]] = metatype $@thin Int.Type
+// CHECK:   [[REG4:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG5:%.*]] = apply [[REG4]]([[REG2]], [[REG3]]) : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG6:%.*]] = function_ref @$s25borrow_accessor_evolution7WrapperVyAA5KlassCSicib : $@convention(method) (Int, @in_guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   [[REG7:%.*]] = apply [[REG6]]([[REG5]], [[REG0]]) : $@convention(method) (Int, @in_guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   return [[REG7]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s25borrow_accessor_evolution3NCSV2ncAA2NCVvb : $@convention(method) (@in_guaranteed NCS) -> @guaranteed_addr NC {
+// CHECK: bb0([[REG0:%.*]] : $*NCS):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG2]], #NCS._nc
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s25borrow_accessor_evolution9NCWrapperV2ncAA2NCVvb : $@convention(method) (@in_guaranteed NCWrapper) -> @guaranteed_addr NC {
+// CHECK: bb0([[REG0:%.*]] : $*NCWrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG2]], #NCWrapper._nc
+// CHECK:   return [[REG3]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s25borrow_accessor_evolution9NCWrapperV7nested1AA2NCVvb : $@convention(method) (@in_guaranteed NCWrapper) -> @guaranteed_addr NC {
+// CHECK: bb0([[REG0:%.*]] : $*NCWrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = struct_element_addr [[REG2]], #NCWrapper._s
+// CHECK:   [[REG4:%.*]] = function_ref @$s25borrow_accessor_evolution3NCSV2ncAA2NCVvb : $@convention(method) (@in_guaranteed NCS) -> @guaranteed_addr NC
+// CHECK:   [[REG5:%.*]] = apply [[REG4]]([[REG3]]) : $@convention(method) (@in_guaranteed NCS) -> @guaranteed_addr NC
+// CHECK:   [[REG6:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG5]]
+// CHECK:   return [[REG6]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s25borrow_accessor_evolution9NCWrapperV7nested2AA2NCVvb : $@convention(method) (@in_guaranteed NCWrapper) -> @guaranteed_addr NC {
+// CHECK: bb0([[REG0:%.*]] : $*NCWrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = function_ref @$s25borrow_accessor_evolution9NCWrapperV2ncAA2NCVvb : $@convention(method) (@in_guaranteed NCWrapper) -> @guaranteed_addr NC
+// CHECK:   [[REG4:%.*]] = apply [[REG3]]([[REG2]]) : $@convention(method) (@in_guaranteed NCWrapper) -> @guaranteed_addr NC
+// CHECK:   [[REG5:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG4]]
+// CHECK:   return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s25borrow_accessor_evolution9NCWrapperVyAA2NCVSicib : $@convention(method) (Int, @in_guaranteed NCWrapper) -> @guaranteed_addr NC {
+// CHECK: bb0([[REG0:%.*]] : $Int, [[REG1:%.*]] : $*NCWrapper):
+// CHECK:   debug_value [[REG0]], let, name "index", argno 1
+// CHECK:   debug_value [[REG1]], let, name "self", argno 2, expr op_deref
+// CHECK:   [[REG4:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG1]]
+// CHECK:   [[REG5:%.*]] = struct_element_addr [[REG4]], #NCWrapper._nc
+// CHECK:   return [[REG5]]
+// CHECK: }
+
+// CHECK: sil hidden [ossa] @$s25borrow_accessor_evolution9NCWrapperV16nested_subscriptAA2NCVvb : $@convention(method) (@in_guaranteed NCWrapper) -> @guaranteed_addr NC {
+// CHECK: bb0([[REG0:%.*]] : $*NCWrapper):
+// CHECK:   debug_value [[REG0]], let, name "self", argno 1, expr op_deref
+// CHECK:   [[REG2:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG0]]
+// CHECK:   [[REG3:%.*]] = integer_literal $Builtin.IntLiteral, 0
+// CHECK:   [[REG4:%.*]] = metatype $@thin Int.Type
+// CHECK:   [[REG5:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG6:%.*]] = apply [[REG5]]([[REG3]], [[REG4]]) : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
+// CHECK:   [[REG7:%.*]] = function_ref @$s25borrow_accessor_evolution9NCWrapperVyAA2NCVSicib : $@convention(method) (Int, @in_guaranteed NCWrapper) -> @guaranteed_addr NC
+// CHECK:   [[REG8:%.*]] = apply [[REG7]]([[REG6]], [[REG2]]) : $@convention(method) (Int, @in_guaranteed NCWrapper) -> @guaranteed_addr NC
+// CHECK:   [[REG9:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[REG8]]
+// CHECK:   return [[REG9]]
+// CHECK: }
+
diff --git a/test/SILGen/borrow_accessor_failues.swift b/test/SILGen/borrow_accessor_failues.swift
new file mode 100644
index 0000000000000..488665bacc6d3
--- /dev/null
+++ b/test/SILGen/borrow_accessor_failues.swift
@@ -0,0 +1,270 @@
+// RUN:%target-swift-frontend -emit-silgen %s -verify  -enable-experimental-feature BorrowAndMutateAccessors
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+
+public class Klass {
+  var id: Int = 0
+}
+
+func get_k() -> Klass {
+  return Klass()
+}
+
+public struct S {
+  var _k: Klass
+
+  var borrow_k: Klass {
+    borrow {
+      return _k
+    }
+  }
+  var get_k: Klass {
+    get {
+      return _k
+    }
+  }
+  var read_k: Klass {
+    _read {
+      yield _k
+    }
+  }
+}
+
+public struct Wrapper {
+  var _k: Klass
+  var _s: S
+
+  var k: Klass {
+    borrow {
+      return _k
+    }
+  }
+
+  var s: S {
+    borrow {
+      return _s
+    }
+  }
+
+  var s_get: S {
+    get {
+      return _s
+    }
+  }
+
+  var s_read: S {
+    _read {
+      yield _s
+    }
+  }
+
+  var nested_get1: Klass {
+    borrow {
+      return _s.get_k // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+
+  var nested_get2: Klass {
+    borrow {
+      return s_get.borrow_k // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+
+  var nested_get3: Int {
+    borrow {
+      return _s.get_k.id // TODO: Diagnose this case
+    }
+  }
+
+  var nested_get4: Int {
+    borrow {
+      return s_get.borrow_k.id // TODO: Diagnose this case
+    }
+  }
+
+  var nested_read1: Klass {
+    borrow {
+      return _s.read_k // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+
+  var nested_read2: Klass {
+    borrow {
+      return s_read.read_k // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+
+  var owned_value_direct: Klass {
+    borrow {
+      return get_k() // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+
+  var owned_value_projected: Klass {
+    borrow {
+      let w = Wrapper(_k: Klass(), _s: S(_k: Klass()))
+      return w.k // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+
+  var if_klass: Klass {
+    borrow {
+      if Int.random(in: 1..<100) == 0 {
+        return _k
+      }
+      return _k // expected-error{{multiple return statements in borrow accessors are not yet supported}}
+    }
+  }
+
+  var tuple_klass: (Klass, Klass) {
+    borrow {
+      return (_k, _k) // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+
+  var opt_klass: Klass? {
+    borrow {
+      if Int.random(in: 1..<100) == 0 {
+        return nil
+      }
+      return _k // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+}
+
+public struct SimpleWrapper<T> {
+  var _prop: T
+
+  var borrow_prop: T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var get_prop: T {
+    get {
+      return _prop
+    }
+  }
+
+  var read_prop: T {
+    _read {
+      yield _prop
+    }
+  }
+}
+
+public struct GenWrapper<T> {
+  var _prop: T
+  var _w: SimpleWrapper<T>
+
+  public var prop: T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var get_prop: T {
+    borrow {
+      return _w.get_prop // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+
+    }
+  }
+
+  var read_prop: T {
+    borrow {
+      return _w.read_prop // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+
+  var if_prop: T {
+    borrow {
+      if Int.random(in: 1..<100) == 0 {
+        return _prop
+      }
+      return _prop // expected-error{{multiple return statements in borrow accessors are not yet supported}}
+    }
+  }
+
+  var tuple_prop: (T, T) {
+    borrow {
+      return (_prop, _prop) // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+
+  var opt_T: T? {
+    borrow {
+      if Int.random(in: 1..<100) == 0 {
+        return nil
+      }
+      return _prop // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+
+    }
+  }
+}
+
+public struct SimpleNCWrapper<T : ~Copyable> : ~Copyable {
+  var _prop: T
+
+  var borrow_prop: T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var get_prop: T {
+    get {
+      return _prop
+    }
+  }
+
+  var read_prop: T {
+    _read {
+      yield _prop
+    }
+  }
+}
+
+public struct GenNCWrapper<T : ~Copyable> : ~Copyable {
+  var _prop: T
+  var _w: SimpleNCWrapper<T>
+
+  public var prop: T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var nested_get: T {
+    borrow {
+      return _w.get_prop // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+
+    }
+  }
+
+  var nested_read: T {
+    borrow {
+      return _w.read_prop // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+
+    }
+  }
+
+  var if_prop: T {
+    borrow {
+      if Int.random(in: 1..<100) == 0 {
+        return _prop
+      }
+      return _prop // expected-error{{multiple return statements in borrow accessors are not yet supported}}
+    }
+  }
+
+  var opt_T: T? {
+    borrow {
+      if Int.random(in: 1..<100) == 0 {
+        return nil
+      }
+      return _prop // expected-error{{invalid return value from borrow accessor}} // expected-note{{borrow accessors can return either literals, stored properties or computed properties that have borrow accessors}}
+    }
+  }
+}
+
diff --git a/test/SILGen/capture-transitive.swift b/test/SILGen/capture-transitive.swift
index 0d77d7ff31c38..fb90b7516f93d 100644
--- a/test/SILGen/capture-transitive.swift
+++ b/test/SILGen/capture-transitive.swift
@@ -1,4 +1,7 @@
-// RUN: %target-swift-emit-silgen %s | %FileCheck %s
+// RUN: %target-swift-emit-silgen %s | %FileCheck %s --check-prefixes=CHECK,CHECK-NO-WEAK-LET
+// RUN: %target-swift-emit-silgen -enable-upcoming-feature ImmutableWeakCaptures %s | %FileCheck %s --check-prefixes=CHECK,CHECK-HAS-WEAK-LET
+
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 // https://github.com/apple/swift/issues/50924
 
diff --git a/test/SILGen/capture_order.swift b/test/SILGen/capture_order.swift
index 55de099718024..1e5e08d7f4b08 100644
--- a/test/SILGen/capture_order.swift
+++ b/test/SILGen/capture_order.swift
@@ -1,4 +1,6 @@
-// RUN: %target-swift-emit-silgen %s -verify
+// RUN: %target-swift-emit-silgen -enable-upcoming-feature ImmutableWeakCaptures %s -verify
+
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 /// We emit an invalid forward capture as an 'undef'; make sure
 /// we cover the various possible cases.
@@ -28,7 +30,7 @@ public func captureBeforeDefWeakVar(obj: AnyObject) -> () -> AnyObject? {
     return weakObj // expected-note {{captured here}}
   }
   let closure = getter
-  weak var weakObj: AnyObject? = obj // expected-note{{captured value declared here}}
+  weak let weakObj: AnyObject? = obj // expected-note{{captured value declared here}}
   return closure
 }
 
@@ -125,7 +127,7 @@ class С_47389 {
     let bar = { [weak self] in
     // expected-error@-1 {{closure captures 'bar' before it is declared}}
     // expected-note@-2 {{captured value declared here}}
-    // expected-warning@-3 {{variable 'self' was written to, but never read}}
+    // expected-warning@-3 {{capture 'self' was never used}}
       bar2()
     }
     func bar2() {
diff --git a/test/SILGen/cdecl-official.swift b/test/SILGen/cdecl-official.swift
new file mode 100644
index 0000000000000..5cea5e93208a7
--- /dev/null
+++ b/test/SILGen/cdecl-official.swift
@@ -0,0 +1,55 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-emit-silgen %s -module-name cdecl \
+// RUN:   -enable-experimental-feature CDecl > %t/out.sil
+// RUN: %FileCheck %s -input-file %t/out.sil
+
+// REQUIRES: swift_feature_CDecl
+
+// CHECK-LABEL: sil hidden [thunk] [ossa] @pear : $@convention(c)
+// CHECK:         function_ref @$s5cdecl5apple{{[_0-9a-zA-Z]*}}F
+// CHECK-LABEL: sil hidden [ossa] @$s5cdecl5apple{{[_0-9a-zA-Z]*}}F
+@c(pear)
+func apple(_ f: @convention(c) (Int) -> Int) { }
+
+// CHECK-LABEL: sil hidden [ossa] @$s5cdecl16forceCEntryPoint{{[_0-9a-zA-Z]*}}F
+// CHECK:         function_ref @grapefruit : $@convention(c) (Int) -> Int
+// CHECK:         function_ref apple(_:)
+// CHECK:         function_ref @$s5cdecl5appleyyS2iXCF : $@convention(thin) (@convention(c) (Int) -> Int) -> ()
+// FIXME should it be function_ref @apple?
+func forceCEntryPoint() {
+  apple(orange)
+}
+
+// CHECK-LABEL: sil hidden [thunk] [ossa] @grapefruit : $@convention(c)
+// CHECK:         function_ref @$s5cdecl6orange{{[_0-9a-zA-Z]*}}F
+// CHECK-LABEL: sil hidden [ossa] @$s5cdecl6orange{{[_0-9a-zA-Z]*}}F
+@c(grapefruit)
+func orange(_ x: Int) -> Int {
+  return x
+}
+
+// CHECK-LABEL: sil [serialized] [thunk] [ossa] @cauliflower : $@convention(c)
+// CHECK:         function_ref @$s5cdecl8broccoli{{[_0-9a-zA-Z]*}}F
+// CHECK-LABEL: sil [ossa] @$s5cdecl8broccoli{{[_0-9a-zA-Z]*}}F
+// FIXME should it be `sil hidden`?
+@c(cauliflower)
+public func broccoli(_ x: Int) -> Int {
+  return x
+}
+
+// CHECK-LABEL: sil private [thunk] [ossa] @collard_greens : $@convention(c)
+// CHECK:         function_ref @$s5cdecl4kale[[PRIVATE:.*]]
+// CHECK:       sil private [ossa] @$s5cdecl4kale[[PRIVATE:.*]]
+@c(collard_greens)
+private func kale(_ x: Int) -> Int {
+  return x
+}
+
+// CHECK-LABEL: sil private [thunk] [ossa] @defaultName : $@convention(c)
+// CHECK:         function_ref @$s5cdecl11defaultName[[PRIVATE:.*]]
+// CHECK:       sil private [ossa] @$s5cdecl11defaultName[[PRIVATE:.*]]
+@c
+private func defaultName(_ x: Int) -> Int {
+  return x
+}
diff --git a/test/SILGen/clang-target-weak-import-globalvar.swift b/test/SILGen/clang-target-weak-import-globalvar.swift
new file mode 100644
index 0000000000000..47c2c629bf4fb
--- /dev/null
+++ b/test/SILGen/clang-target-weak-import-globalvar.swift
@@ -0,0 +1,69 @@
+// REQUIRES: objc_interop
+// REQUIRES: OS=macosx
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/deps)
+// RUN: %empty-directory(%t/inputs)
+// RUN: split-file %s %t
+
+// - Prepare the explicit input map
+// RUN: sed -e "s|INPUTSDIR|%/t/inputs|g" %t/map.json.template > %t/map.json.template1
+// RUN: sed -e "s|STDLIBMOD|%/stdlib_module|g" %t/map.json.template1 > %t/map.json.template2
+// RUN: sed -e "s|ONONEMOD|%/ononesupport_module|g" %t/map.json.template2 > %t/map.json.template3
+// RUN: sed -e "s|CHEADERSDIR|%t/deps|g" %t/map.json.template3 > %t/map.json.template4
+// RUN: sed -e "s|SWIFTLIBDIR|%swift-lib-dir|g" %t/map.json.template4 > %t/map.json
+
+// - Set up explicit dependencies for the client
+// RUN: %target-swift-emit-pcm -module-name SwiftShims %swift-lib-dir/swift/shims/module.modulemap -o %t/inputs/SwiftShims.pcm -target %target-cpu-apple-macosx26.0 -Xcc -Xclang -Xcc -fbuiltin-headers-in-system-modules
+// RUN: %target-swift-emit-pcm -module-name Foo %t/deps/module.modulemap -o %t/inputs/Foo.pcm -target %target-cpu-apple-macosx26.0 -Xcc -Xclang -Xcc -fbuiltin-headers-in-system-modules
+
+// - Build the client
+// RUN: %target-swift-frontend -c %t/client.swift -explicit-swift-module-map-file %t/map.json -disable-implicit-swift-modules -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -o %t/client.o -target %target-cpu-apple-macosx15.5 -clang-target %target-cpu-apple-macosx26.0  -Xcc -Xclang -Xcc -fbuiltin-headers-in-system-modules
+
+// - Ensure that the client's code-gen treats 'brandNewInteger' as a weak external symbol
+// RUN: %llvm-nm -m %t/client.o | %FileCheck %s
+// CHECK: (undefined) weak external _brandNewInteger
+
+//--- deps/Foo.h
+__attribute__((availability(macosx,introduced=26.0)))
+__attribute__((visibility("default")))
+const extern void* __nonnull brandNewInteger;
+
+//--- deps/module.modulemap
+module Foo {
+    header "Foo.h"
+    export *
+}
+
+//--- map.json.template
+[
+  {
+      "moduleName": "Foo",
+      "clangModulePath": "INPUTSDIR/Foo.pcm",
+      "clangModuleMapPath": "CHEADERSDIR/module.modulemap"
+  },
+  {
+      "moduleName": "Swift",
+      "modulePath": "STDLIBMOD",
+      "isFramework": false
+  },
+  {
+      "moduleName": "SwiftOnoneSupport",
+      "modulePath": "ONONEMOD",
+      "isFramework": false
+  },
+  {
+      "moduleName": "SwiftShims",
+      "isFramework": false,
+      "clangModuleMapPath": "SWIFTLIBDIR/swift/shims/module.modulemap",
+      "clangModulePath": "INPUTSDIR/SwiftShims.pcm"
+}]
+
+
+//--- client.swift
+import Foo
+func f() {
+	if #available(macOS 26.0, *) {
+		print(brandNewInteger)
+	}
+}
diff --git a/test/SILGen/clang-target-weak-import.swift b/test/SILGen/clang-target-weak-import.swift
new file mode 100644
index 0000000000000..c50ef9cf770d0
--- /dev/null
+++ b/test/SILGen/clang-target-weak-import.swift
@@ -0,0 +1,70 @@
+// REQUIRES: objc_interop
+// REQUIRES: OS=macosx
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/inputs)
+// RUN: %empty-directory(%t/cheaders)
+
+// RUN: split-file %s %t
+// RUN: sed -e "s|INPUTSDIR|%/t/inputs|g" %t/map.json.template > %t/map.json.template1
+// RUN: sed -e "s|STDLIBMOD|%/stdlib_module|g" %t/map.json.template1 > %t/map.json.template2
+// RUN: sed -e "s|ONONEMOD|%/ononesupport_module|g" %t/map.json.template2 > %t/map.json.template3
+// RUN: sed -e "s|CHEADERSDIR|%t/cheaders|g" %t/map.json.template3 > %t/map.json.template4
+// RUN: sed -e "s|SWIFTLIBDIR|%swift-lib-dir|g" %t/map.json.template4 > %t/map.json
+
+// RUN: %target-swift-emit-pcm -module-name Bar -o %t/inputs/Bar.pcm %t/cheaders/module.modulemap -target %target-cpu-apple-macosx15.0
+// RUN: %target-swift-emit-pcm -module-name SwiftShims %swift-lib-dir/swift/shims/module.modulemap -o %t/inputs/SwiftShims.pcm -target %target-cpu-apple-macosx15.0
+
+// RUN: %target-swift-frontend -c -disable-implicit-swift-modules -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -module-cache-path %t/module-cache -explicit-swift-module-map-file %t/map.json -primary-file %t/test.swift -o %t/test.o -target %target-cpu-apple-macosx14.0 -clang-target %target-cpu-apple-macosx15.0
+
+// RUN: %llvm-nm -m %t/test.o | %FileCheck %s
+// CHECK: (undefined) weak external _funcBar
+// CHECK: (undefined) external _funcBarButOlder
+
+//--- map.json.template
+[
+  {
+      "moduleName": "Bar",
+      "clangModulePath": "INPUTSDIR/Bar.pcm",
+      "clangModuleMapPath": "CHEADERSDIR/module.modulemap"
+  },
+  {
+      "moduleName": "Swift",
+      "modulePath": "STDLIBMOD",
+      "isFramework": false
+  },
+  {
+      "moduleName": "SwiftOnoneSupport",
+      "modulePath": "ONONEMOD",
+      "isFramework": false
+  },
+  {
+      "moduleName": "SwiftShims",
+      "isFramework": false,
+      "clangModuleMapPath": "SWIFTLIBDIR/swift/shims/module.modulemap",
+      "clangModulePath": "INPUTSDIR/SwiftShims.pcm"
+}]
+
+//--- cheaders/module.modulemap
+module Bar {
+  header "Bar.h"
+  export *
+}
+
+//--- cheaders/Bar.h
+#pragma clang attribute push (__attribute__((availability(macOS, introduced=15.0))), apply_to=function)
+extern int funcBar(void);
+#pragma clang attribute pop
+
+#pragma clang attribute push (__attribute__((availability(macOS, introduced=14.0))), apply_to=function)
+extern int funcBarButOlder(void);
+#pragma clang attribute pop
+
+//--- test.swift
+import Bar
+public func foo() {
+    let _ = funcBarButOlder()
+    if #available(macOS 15.0, *), funcBar() != 0 {
+        print("Hello, World!")
+    }
+}
diff --git a/test/SILGen/clang_records_addressable_for_dependencies.swift b/test/SILGen/clang_records_addressable_for_dependencies.swift
new file mode 100644
index 0000000000000..cb2265fd5eff5
--- /dev/null
+++ b/test/SILGen/clang_records_addressable_for_dependencies.swift
@@ -0,0 +1,16 @@
+// RUN: %target-swift-emit-silgen -import-objc-header %S/Inputs/clang_records_addressable_for_dependencies.h -enable-experimental-feature Lifetimes %s | %FileCheck %s
+
+// REQUIRES: swift_feature_Lifetimes
+
+struct Dependent: ~Escapable {
+	@_lifetime(immortal)
+	init() { fatalError() }
+}
+
+// CHECK-LABEL: sil {{.*}} @${{.*}}12dependenceOn7cStruct{{.*}} : $@convention(thin) (@in_guaranteed CStruct)
+@_lifetime(cStruct)
+func dependenceOn(cStruct: CStruct) -> Dependent { fatalError() }
+
+// CHECK-LABEL: sil {{.*}} @${{.*}}12dependenceOn6cUnion{{.*}} : $@convention(thin) (@in_guaranteed CUnion)
+@_lifetime(cUnion)
+func dependenceOn(cUnion: CUnion) -> Dependent { fatalError() }
diff --git a/test/SILGen/conditional_conformance.swift b/test/SILGen/conditional_conformance.swift
index ee195fecf5109..4bade33b01458 100644
--- a/test/SILGen/conditional_conformance.swift
+++ b/test/SILGen/conditional_conformance.swift
@@ -20,7 +20,7 @@ extension Conformance: P1 where A: P2 {
 // This is defined below but is emitted before any witness tables.
 // Just make sure it does not have a generic signature.
 //
-// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s23conditional_conformance16SameTypeConcreteVyxGAA2P1AASiRszlAaEP6normalyyFTW : $@convention(witness_method: P1) (@in_guaranteed SameTypeConcrete<Int>) -> ()
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s23conditional_conformance11ConformanceVyxGAA2P1A2A2P2RzlAaEP6normalyyFTW : $@convention(witness_method: P1) <τ_0_0 where τ_0_0 : P2> (@in_guaranteed Conformance<τ_0_0>) -> () {
 
 
 // CHECK-LABEL: sil_witness_table hidden <A where A : P2> Conformance<A>: P1 module conditional_conformance {
@@ -48,8 +48,8 @@ extension SameTypeConcrete: P1 where B == Int {
 }
 
 // CHECK-LABEL: sil_witness_table hidden <B where B == Int> SameTypeConcrete<B>: P1 module conditional_conformance {
-// CHECK-NEXT:    method #P1.normal: <Self where Self : P1> (Self) -> () -> () : @$s23conditional_conformance16SameTypeConcreteVyxGAA2P1AASiRszlAaEP6normalyyFTW	// protocol witness for P1.normal() in conformance <A> SameTypeConcrete<A>
-// CHECK-NEXT:    method #P1.generic: <Self where Self : P1><T where T : P3> (Self) -> (T) -> () : @$s23conditional_conformance16SameTypeConcreteVyxGAA2P1AASiRszlAaEP7genericyyqd__AA2P3Rd__lFTW	// protocol witness for P1.generic<A>(_:) in conformance <A> SameTypeConcrete<A>
+// CHECK-NEXT:    method #P1.normal: <Self where Self : P1> (Self) -> () -> () : @$s23conditional_conformance16SameTypeConcreteVySiGAA2P1A2aEP6normalyyFTW	// protocol witness for P1.normal() in conformance SameTypeConcrete<Int>
+// CHECK-NEXT:    method #P1.generic: <Self where Self : P1><T where T : P3> (Self) -> (T) -> () : @$s23conditional_conformance16SameTypeConcreteVySiGAA2P1A2aEP7genericyyqd__AA2P3Rd__lFTW	// protocol witness for P1.generic<A>(_:) in conformance SameTypeConcrete<Int>
 // CHECK-NEXT:  }
 
 struct SameTypeGeneric<C, D> {}
diff --git a/test/SILGen/conditionally_copyable_conformance_descriptor.swift b/test/SILGen/conditionally_copyable_conformance_descriptor.swift
new file mode 100644
index 0000000000000..8138071a01a20
--- /dev/null
+++ b/test/SILGen/conditionally_copyable_conformance_descriptor.swift
@@ -0,0 +1,180 @@
+// RUN: %target-swift-emit-silgen -enable-library-evolution %s | %FileCheck %s
+
+public struct ConditionallyCopyable<T: ~Copyable>: ~Copyable {
+}
+
+extension ConditionallyCopyable: Copyable where T: Copyable {}
+
+public struct NeverCopyable: ~Copyable {}
+
+public struct Index<U: ~Copyable>: Hashable { }
+
+extension ConditionallyCopyable where T: ~Copyable {
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.sometimesCopyableBase_sometimesCopyableValue
+    // CHECK-SAME:    getter @{{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0> (@in_guaranteed ConditionallyCopyable<τ_0_0>) -> @out τ_0_0
+    // CHECK-SAME:    setter @{{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0> (@in_guaranteed τ_0_0, @inout ConditionallyCopyable<τ_0_0>) -> ()
+    public private(set) var sometimesCopyableBase_sometimesCopyableValue: T {
+        get { }
+        set { }
+    }
+
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.sometimesCopyableBase_alwaysCopyableValue
+    // CHECK-SAME:    getter @{{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0> (@in_guaranteed ConditionallyCopyable<τ_0_0>) -> @out Int
+    // CHECK-SAME:    setter @{{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0> (@in_guaranteed Int, @inout ConditionallyCopyable<τ_0_0>) -> ()
+    public private(set) var sometimesCopyableBase_alwaysCopyableValue: Int {
+        get { }
+        set { }
+    }
+
+    // CHECK-NOT: sil_property #ConditionallyCopyable.neverCopyableBase_alwaysCopyableValue
+    public private(set) var sometimesCopyableBase_neverCopyableValue: NeverCopyable {
+        get { }
+        set { }
+    }
+
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.subscript{{.*}}, id @$s45conditionally_copyable_conformance_descriptor21ConditionallyCopyableVAARi_zrlE09sometimesf5Base_gF10IndexValueqd__AA0I0Vyqd__G_tcRi_d__luir
+    // CHECK-SAME:    getter @{{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0><τ_1_0> (@in_guaranteed ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> @out τ_1_0
+    // CHECK-SAME:    setter @{{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0><τ_1_0> (@in_guaranteed τ_1_0, @inout ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> ()
+    public private(set) subscript<U: ~Copyable>(
+        sometimesCopyableBase_sometimesCopyableIndexValue _: Index<U>
+    ) -> U {
+        get { }
+        set { }
+    }
+
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.subscript{{.*}}, id @$s45conditionally_copyable_conformance_descriptor21ConditionallyCopyableVAARi_zrlE09sometimesf5Base_gF5ValuexAA5IndexVyqd__G_tcRi_d__luir
+    // CHECK-SAME:    getter @{{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0><τ_1_0 where τ_1_0 : ~Copyable> (@in_guaranteed ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> @out τ_0_0
+    // CHECK-SAME:    setter @{{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0><τ_1_0 where τ_1_0 : ~Copyable> (@in_guaranteed τ_0_0, @inout ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> ()
+    public private(set) subscript<U: ~Copyable>(
+        sometimesCopyableBase_sometimesCopyableValue _: Index<U>
+    ) -> T {
+        get { }
+        set { }
+    }
+
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.subscript{{.*}}, id @$s45conditionally_copyable_conformance_descriptor21ConditionallyCopyableVAARi_zrlE09sometimesf11Base_alwaysF5ValueSiAA5IndexVyqd__G_tcRi_d__luig
+    // CHECK-SAME:    getter @{{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0><τ_1_0 where τ_1_0 : ~Copyable> (@in_guaranteed ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> @out Int
+    // CHECK-SAME:    setter @{{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0><τ_1_0 where τ_1_0 : ~Copyable> (@in_guaranteed Int, @inout ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> ()
+    public private(set) subscript<U: ~Copyable>(
+        sometimesCopyableBase_alwaysCopyableValue _: Index<U>
+    ) -> Int {
+        get { }
+        set { }
+    }
+
+    // CHECK-NOT: sil_property #ConditionallyCopyable.subscript{{.*}}never
+    public private(set) subscript<U: ~Copyable>(
+        sometimesCopyableBase_neverCopyableValue _: Index<U>
+    ) -> NeverCopyable {
+        get { }
+        set { }
+    }
+}
+
+extension ConditionallyCopyable where T == NeverCopyable, T: ~Copyable {
+    // CHECK-NOT: sil_property #ConditionallyCopyable.neverCopyableBase_sometimesCopyableValue
+    public private(set) var neverCopyableBase_sometimesCopyableValue: T {
+        get { }
+        set { }
+    }
+
+    // CHECK-NOT: sil_property #ConditionallyCopyable.neverCopyableBase_alwaysCopyableValue
+    public private(set) var neverCopyableBase_alwaysCopyableValue: Int {
+        get { }
+        set { }
+    }
+
+    // CHECK-NOT: sil_property #ConditionallyCopyable.neverCopyableBase_neverCopyableValue
+    public private(set) var neverCopyableBase_neverCopyableValue: NeverCopyable {
+        get { }
+        set { }
+    }
+
+    // CHECK-NOT: sil_property #ConditionallyCopyable.subscript{{.*}}never
+    public private(set) subscript<U: ~Copyable>(
+        neverCopyableBase_sometimesCopyableIndexValue _: Index<U>
+    ) -> U {
+        get { }
+        set { }
+    }
+    public private(set) subscript<U: ~Copyable>(
+        neverCopyableBase_sometimesCopyableValue _: Index<U>
+    ) -> T {
+        get { }
+        set { }
+    }
+    public private(set) subscript<U: ~Copyable>(
+        neverCopyableBase_alwaysCopyableValue _: Index<U>
+    ) -> Int {
+        get { }
+        set { }
+    }
+    public private(set) subscript<U: ~Copyable>(
+        neverCopyableBase_neverCopyableValue _: Index<U>
+    ) -> NeverCopyable {
+        get { }
+        set { }
+    }
+}
+
+extension ConditionallyCopyable where T: Copyable {
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.alwaysCopyableBase_sometimesCopyableValue
+    // CHECK-SAME:    getter {{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0> (@in_guaranteed ConditionallyCopyable<τ_0_0>) -> @out τ_0_0
+    // CHECK-SAME:    setter {{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0> (@in_guaranteed τ_0_0, @inout ConditionallyCopyable<τ_0_0>) -> ()
+    public private(set) var alwaysCopyableBase_sometimesCopyableValue: T {
+        get { }
+        set { }
+    }
+
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.alwaysCopyableBase_alwaysCopyableValue
+    // CHECK-SAME:    getter {{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0> (@in_guaranteed ConditionallyCopyable<τ_0_0>) -> @out Int
+    // CHECK-SAME:    setter {{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0> (@in_guaranteed Int, @inout ConditionallyCopyable<τ_0_0>) -> ()
+    public private(set) var alwaysCopyableBase_alwaysCopyableValue: Int {
+        get { }
+        set { }
+    }
+
+    // CHECK-NOT: sil_property alwaysCopyableBase_neverCopyableValue
+    public private(set) var alwaysCopyableBase_neverCopyableValue: NeverCopyable {
+        get { }
+        set { }
+    }
+
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.subscript{{.*}}, id @$s45conditionally_copyable_conformance_descriptor21ConditionallyCopyableV06alwaysf14Base_sometimesF10IndexValueqd__AA0J0Vyqd__G_tcRi_d__luir
+    // CHECK-SAME:    getter {{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0><τ_1_0> (@in_guaranteed ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> @out τ_1_0
+    // CHECK-SAME:    setter {{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0><τ_1_0> (@in_guaranteed τ_1_0, @inout ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> ())
+    public private(set) subscript<U: ~Copyable>(
+        alwaysCopyableBase_sometimesCopyableIndexValue _: Index<U>
+    ) -> U {
+        get { }
+        set { }
+    }
+
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.subscript{{.*}}, id @$s45conditionally_copyable_conformance_descriptor21ConditionallyCopyableV06alwaysf14Base_sometimesF5ValuexAA5IndexVyqd__G_tcRi_d__luig
+    // CHECK-SAME:    getter {{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0><τ_1_0 where τ_1_0 : ~Copyable> (@in_guaranteed ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> @out τ_0_0
+    // CHECK-SAME:    setter {{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0><τ_1_0 where τ_1_0 : ~Copyable> (@in_guaranteed τ_0_0, @inout ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> ()
+    public private(set) subscript<U: ~Copyable>(
+        alwaysCopyableBase_sometimesCopyableValue _: Index<U>
+    ) -> T {
+        get { }
+        set { }
+    }
+
+    // CHECK-LABEL: sil_property #ConditionallyCopyable.subscript{{.*}}, id @$s45conditionally_copyable_conformance_descriptor21ConditionallyCopyableV06alwaysf5Base_gF5ValueSiAA5IndexVyqd__G_tcRi_d__luig
+    // CHECK-SAME:    getter {{[^ ]*}} : $@convention(keypath_accessor_getter) <τ_0_0><τ_1_0 where τ_1_0 : ~Copyable> (@in_guaranteed ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> @out Int
+    // CHECK-SAME:    setter {{[^ ]*}} : $@convention(keypath_accessor_setter) <τ_0_0><τ_1_0 where τ_1_0 : ~Copyable> (@in_guaranteed Int, @inout ConditionallyCopyable<τ_0_0>, @in_guaranteed Index<τ_1_0>) -> ()
+    public private(set) subscript<U: ~Copyable>(
+        alwaysCopyableBase_alwaysCopyableValue _: Index<U>
+    ) -> Int {
+        get { }
+        set { }
+    }
+
+    // CHECK-NOT: sil_property #ConditionallyCopyable.subscript{{.*}}never
+    public private(set) subscript<U: ~Copyable>(
+        alwaysCopyableBase_neverCopyableValue _: Index<U>
+    ) -> NeverCopyable {
+        get { }
+        set { }
+    }
+}
diff --git a/test/SILGen/constrained_extensions.swift b/test/SILGen/constrained_extensions.swift
index bf0a362376046..9c98d8a74b086 100644
--- a/test/SILGen/constrained_extensions.swift
+++ b/test/SILGen/constrained_extensions.swift
@@ -254,7 +254,7 @@ extension S: HasX where T == Int {
   }
 }
 
-// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s22constrained_extensions1SVyxGAA4HasXAASiRszlAaEP1xSivMTW : $@yield_once @convention(witness_method: HasX) @substituted <τ_0_0> (@inout τ_0_0) -> @yields @inout Int for <S<Int>> {
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s22constrained_extensions1SVySiGAA4HasXA2aEP1xSivMTW : $@yield_once @convention(witness_method: HasX) @substituted <τ_0_0> (@inout τ_0_0) -> @yields @inout Int for <S<Int>> {
 // CHECK: [[WITNESS_FN:%.*]] = function_ref @$s22constrained_extensions1SVAASiRszlE1xSivM : $@yield_once @convention(method) (@inout S<Int>) -> @yields @inout Int
 // CHECK: begin_apply [[WITNESS_FN]](%0) : $@yield_once @convention(method) (@inout S<Int>) -> @yields @inout Int
 // CHECK: yield
diff --git a/test/SILGen/copy_expr.swift b/test/SILGen/copy_expr.swift
index 1cb51175f879e..5c08b268b19d5 100644
--- a/test/SILGen/copy_expr.swift
+++ b/test/SILGen/copy_expr.swift
@@ -29,8 +29,7 @@ struct ContainKlass {
 // CHECK: [[X:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thin ContainKlass.Type) -> @owned ContainKlass
 // CHECK: [[MOVE:%.*]] = move_value [lexical] [var_decl] [[X]]
 // CHECK: [[BORROW:%.*]] = begin_borrow [[MOVE]]
-// CHECK: [[COPY_BORROW:%.*]] = copy_value [[BORROW]]
-// CHECK: explicit_copy_value [[COPY_BORROW]]
+// CHECK: [[COPY_BORROW:%.*]] = explicit_copy_value [[BORROW]]
 // CHECK: } // end sil function '$s9copy_expr22testCopyLoadableRValueyyF'
 func testCopyLoadableRValue() {
   let x = ContainKlass()
@@ -121,43 +120,35 @@ func testCopyAddressOnlyLValueArg<T : P>(_ x: inout T) {
 // CHECK: [[X:%.*]] = begin_borrow [[MOVE]]
 //
 // Calling consumeFunc.
-// CHECK: [[COPY_X:%.*]] = copy_value [[X]]
-// CHECK: [[EXPLICIT_COPY_X:%.*]] = explicit_copy_value [[COPY_X]]
+// CHECK: [[EXPLICIT_COPY_X:%.*]] = explicit_copy_value [[X]]
 // CHECK: [[FUNC:%.*]] = function_ref @$s9copy_expr12ContainKlassV11consumeFuncyyF : $@convention(method) (@owned ContainKlass) -> ()
 // CHECK: apply [[FUNC]]([[EXPLICIT_COPY_X]])
-// CHECK: destroy_value [[COPY_X]]
 //
 // Calling borrowingFunc.
 // CHECK: [[X:%.*]] = begin_borrow [[MOVE]]
-// CHECK: [[COPY_X:%.*]] = copy_value [[X]]
-// CHECK: [[EXPLICIT_COPY_X:%.*]] = explicit_copy_value [[COPY_X]]
+// CHECK: [[EXPLICIT_COPY_X:%.*]] = explicit_copy_value [[X]]
 // CHECK: [[FUNC:%.*]] = function_ref @$s9copy_expr12ContainKlassV13borrowingFuncyyF : $@convention(method) (@guaranteed ContainKlass) -> ()
 // CHECK: apply [[FUNC]]([[EXPLICIT_COPY_X]])
 // CHECK: destroy_value [[EXPLICIT_COPY_X]]
-// CHECK: destroy_value [[COPY_X]]
 //
 // Calling computedK. It is borrowed.
 // CHECK: [[X:%.*]] = begin_borrow [[MOVE]]
-// CHECK: [[COPY_X:%.*]] = copy_value [[X]]
-// CHECK: [[EXPLICIT_COPY_X:%.*]] = explicit_copy_value [[COPY_X]]
+// CHECK: [[EXPLICIT_COPY_X:%.*]] = explicit_copy_value [[X]]
 // CHECK: [[BORROW_EXPLICIT_COPY_X:%.*]] = begin_borrow [[EXPLICIT_COPY_X]]
 // CHECK: [[FUNC:%.*]] = function_ref @$s9copy_expr12ContainKlassV9computedKAA0D0Cvg : $@convention(method) (@guaranteed ContainKlass) -> @owned Klass
 // CHECK: apply [[FUNC]]([[BORROW_EXPLICIT_COPY_X]])
 // CHECK: end_borrow [[BORROW_EXPLICIT_COPY_X]]
 // CHECK: destroy_value [[EXPLICIT_COPY_X]]
-// CHECK: destroy_value [[COPY_X]]
 //
 // Calling computed getter.
 // CHECK: [[X:%.*]] = begin_borrow [[MOVE]]
-// CHECK: [[COPY_X:%.*]] = copy_value [[X]]
-// CHECK: [[EXPLICIT_COPY_X:%.*]] = explicit_copy_value [[COPY_X]]
+// CHECK: [[EXPLICIT_COPY_X:%.*]] = explicit_copy_value [[X]]
 // CHECK: [[BORROW_EXPLICIT_COPY_X:%.*]] = begin_borrow [[EXPLICIT_COPY_X]]
 // CHECK: [[COPY_BORROW_EXPLICIT_COPY_X:%.*]] = copy_value [[BORROW_EXPLICIT_COPY_X]]
 // CHECK: [[FUNC:%.*]] = function_ref @$s9copy_expr12ContainKlassV18consumingComputedKAA0D0Cvg : $@convention(method) (@owned ContainKlass) -> @owned Klass
 // CHECK: apply [[FUNC]]([[COPY_BORROW_EXPLICIT_COPY_X]])
 // CHECK: end_borrow [[BORROW_EXPLICIT_COPY_X]]
 // CHECK: destroy_value [[EXPLICIT_COPY_X]]
-// CHECK: destroy_value [[COPY_X]]
 // CHECK: } // end sil function '$s9copy_expr31testCallMethodOnLoadableLetCopyyyF'
 func testCallMethodOnLoadableLetCopy() {
   let x = ContainKlass()
@@ -439,3 +430,9 @@ func testCallMethodOnAddressOnlyInOutCopy<T : P>(_ x: inout T) {
   _ = (copy x).computedK
   _ = (copy x).consumingComputedK
 }
+
+struct Trivial: BitwiseCopyable { var x: Int }
+
+func copyTrivial(x: inout Trivial) -> Trivial {
+    return copy x
+}
diff --git a/test/SILGen/copy_operator.swift b/test/SILGen/copy_operator.swift
index 422ef90f7a654..d701fa61d77d4 100644
--- a/test/SILGen/copy_operator.swift
+++ b/test/SILGen/copy_operator.swift
@@ -11,9 +11,7 @@ class Klass {}
 // CHECK-LABEL: sil [ossa] @$s8moveonly7useCopyyAA5KlassCADF : {{.*}} {
 // CHECK:       bb0([[ARG:%.*]] :
 // CHECK-NEXT:    debug_value
-// CHECK-NEXT:    [[COPY:%[^,]+]] = copy_value [[ARG]]
-// CHECK-NEXT:    [[EXPLICIT_COPY:%[^,]+]] = explicit_copy_value [[COPY]]
-// CHECK-NEXT:    destroy_value [[COPY]]
+// CHECK-NEXT:    [[EXPLICIT_COPY:%[^,]+]] = explicit_copy_value [[ARG]]
 // CHECK-NEXT:    return [[EXPLICIT_COPY]]
 // CHECK-LABEL: } // end sil function '$s8moveonly7useCopyyAA5KlassCADF'
 
@@ -21,8 +19,6 @@ class Klass {}
 // CHECK-SIL:       bb0([[ARG:%.*]] : $Klass):
 // CHECK-SIL-NEXT:    debug_value
 // CHECK-SIL-NEXT:    strong_retain [[ARG]]
-// CHECK-SIL-NEXT:    strong_retain [[ARG]]
-// CHECK-SIL-NEXT:    strong_release [[ARG]]
 // CHECK-SIL-NEXT:    return [[ARG]] : $Klass
 // CHECK-SIL-LABEL: } // end sil function '$s8moveonly7useCopyyAA5KlassCADF'
 
@@ -39,9 +35,7 @@ public func useCopy(_ k: Klass) -> Klass {
 // CHECK-LABEL: sil [ossa] @$s8moveonly7useCopyyxxRlzClF : $@convention(thin) <T where T : AnyObject> (@guaranteed T) -> @owned T {
 // CHECK:       bb0([[ARG:%.*]] :
 // CHECK-NEXT:    debug_value
-// CHECK-NEXT:    [[COPY:%[^,]+]] = copy_value [[ARG]]
-// CHECK-NEXT:    [[EXPLICIT_COPY:%[^,]+]] = explicit_copy_value [[COPY]]
-// CHECK-NEXT:    destroy_value [[COPY]]
+// CHECK-NEXT:    [[EXPLICIT_COPY:%[^,]+]] = explicit_copy_value [[ARG]]
 // CHECK-NEXT:    return [[EXPLICIT_COPY]]
 // CHECK-LABEL: } // end sil function '$s8moveonly7useCopyyxxRlzClF'
 
@@ -49,8 +43,6 @@ public func useCopy(_ k: Klass) -> Klass {
 // CHECK-SIL:       bb0([[ARG:%.*]] :
 // CHECK-SIL-NEXT:    debug_value
 // CHECK-SIL-NEXT:    strong_retain [[ARG]]
-// CHECK-SIL-NEXT:    strong_retain [[ARG]]
-// CHECK-SIL-NEXT:    strong_release [[ARG]]
 // CHECK-SIL-NEXT:    return [[ARG]]
 // CHECK-SIL-LABEL: } // end sil function '$s8moveonly7useCopyyxxRlzClF'
 
diff --git a/test/SILGen/coroutine_accessors.swift b/test/SILGen/coroutine_accessors.swift
index a06a224cecd90..1630b058c3742 100644
--- a/test/SILGen/coroutine_accessors.swift
+++ b/test/SILGen/coroutine_accessors.swift
@@ -1,11 +1,13 @@
-// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types                           \
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types   \
 // RUN:     %s                                              \
+// RUN:     -enable-callee-allocated-coro-abi               \
 // RUN:     -enable-library-evolution                       \
 // RUN:     -enable-experimental-feature CoroutineAccessors \
 // RUN: | %FileCheck %s --check-prefixes=CHECK,CHECK-NOUNWIND
 
-// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types                                              \
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types                      \
 // RUN:     %s                                                                 \
+// RUN:     -enable-callee-allocated-coro-abi                                  \
 // RUN:     -enable-library-evolution                                          \
 // RUN:     -enable-experimental-feature CoroutineAccessors                    \
 // RUN:     -enable-experimental-feature CoroutineAccessorsUnwindOnCallerError \
@@ -158,6 +160,52 @@ mutating func update(irm newValue: Int) throws -> Int {
   try coroutine_accessors.update(at: &irm, to: newValue)
 }
 
+public var i_r_m: Int {
+// CHECK-LABEL: sil{{.*}} [ossa] @$s19coroutine_accessors1SV5i_r_mSivr :
+// CHECK-SAME:      $@yield_once
+// CHECK-SAME:      @convention(method)
+// CHECK-SAME:      (@guaranteed S)
+// CHECK-SAME:      ->
+// CHECK-SAME:      @yields Int
+// CHECK-SAME:  {
+// CHECK:       } // end sil function '$s19coroutine_accessors1SV5i_r_mSivr'
+
+  _read {
+    yield _i
+  }
+// CHECK-NOT:   sil [ossa] @$s19coroutine_accessors1SV5i_r_mSivx :
+// CHECK-LABEL: sil {{.*}}[ossa] @$s19coroutine_accessors1SV5i_r_mSivM :
+// CHECK-SAME:      $@yield_once
+// CHECK-SAME:      @convention(method)
+// CHECK-SAME:      (@inout S)
+// CHECK-SAME:      ->
+// CHECK-SAME:      @yields @inout Int
+// CHECK-SAME:  {
+// CHECK:       } // end sil function '$s19coroutine_accessors1SV5i_r_mSivM'
+  _modify {
+    yield &_i
+  }
+// CHECK-LABEL: sil {{.*}}[ossa] @$s19coroutine_accessors1SV5i_r_mSivs :
+// CHECK-SAME:      $@convention(method)
+// CHECK-SAME:      (Int, @inout S)
+// CHECK-SAME:      ->
+// CHECK-SAME:      ()
+// CHECK-SAME:  {
+// CHECK:       bb0(
+// CHECK-SAME:      [[NEW_VALUE:%[^,]+]] :
+// CHECK-SAME:      [[SELF:%[^,]+]] :
+// CHECK-SAME:  ):
+// CHECK:         [[SELF_ACCESS:%[^,]+]] = begin_access [modify] [unknown] [[SELF]]
+// CHECK:         [[MODIFY_ACCESSOR:%[^,]+]] = function_ref @$s19coroutine_accessors1SV5i_r_mSivM
+// CHECK:         ([[VALUE_ADDRESS:%[^,]+]],
+// CHECK-SAME:     [[TOKEN:%[^)]+]])
+// CHECK-SAME:    = begin_apply [[MODIFY_ACCESSOR]]([[SELF_ACCESS]])
+// CHECK:         assign [[NEW_VALUE:%[^,]+]] to [[VALUE_ADDRESS]]
+// CHECK:         end_apply [[TOKEN]]
+// CHECK:         end_access [[SELF_ACCESS]]
+// CHECK-LABEL:} // end sil function '$s19coroutine_accessors1SV5i_r_mSivs'
+} // public var irm
+
 } // public struct S
 
 enum E : Error {
diff --git a/test/SILGen/coroutine_accessors_availability.swift b/test/SILGen/coroutine_accessors_availability.swift
new file mode 100644
index 0000000000000..aac2b43edcfe3
--- /dev/null
+++ b/test/SILGen/coroutine_accessors_availability.swift
@@ -0,0 +1,390 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-emit-silgen                           \
+// RUN:     %t/Library.swift                                \
+// RUN:     -enable-library-evolution                       \
+// RUN:     -module-name Library                            \
+// RUN:     -enable-experimental-feature CoroutineAccessors \
+// RUN:     -I %t                                           \
+// RUN: | %FileCheck %t/Library.swift --check-prefixes=CHECK
+
+// RUN: %target-swift-frontend                              \
+// RUN:     %t/Library.swift                                \
+// RUN:     -emit-module                                    \
+// RUN:     -enable-library-evolution                       \
+// RUN:     -module-name Library                            \
+// RUN:     -enable-experimental-feature CoroutineAccessors \
+// RUN:     -emit-module-path %t/Library.swiftmodule
+
+// RUN: %target-swift-emit-silgen                           \
+// RUN:     %t/Downstream.swift                             \
+// RUN:     -target %target-swift-5.9-abi-triple            \
+// RUN:     -module-name main                               \
+// RUN:     -enable-experimental-feature CoroutineAccessors \
+// RUN:     -lLibrary                                       \
+// RUN:     -I %t                                           \
+// RUN: | %FileCheck %t/Downstream.swift --check-prefixes=CHECK,CHECK-OLD
+
+// RUN: %target-swift-emit-silgen                           \
+// RUN:     %t/Downstream.swift                             \
+// TODO: CoroutineAccessors: Change to %target-swift-x.y-abi-triple
+// RUN:     -target %target-future-triple                   \
+// RUN:     -module-name main                               \
+// RUN:     -enable-experimental-feature CoroutineAccessors \
+// RUN:     -lLibrary                                       \
+// RUN:     -I %t                                           \
+// RUN: | %FileCheck %t/Downstream.swift --check-prefixes=CHECK,CHECK-NEW
+
+// REQUIRES: swift_stable_abi
+// REQUIRES: swift_feature_CoroutineAccessors
+
+//--- Library.swift
+
+extension Int {
+  public mutating func increment() {
+    self = self + 1
+  }
+}
+
+// TODO: CoroutineAccessors: Change to X.Y throughout file.
+@available(SwiftStdlib 9999, *)
+public struct StructNew {
+  var _i: Int
+  public var i: Int {
+    read {
+      yield _i
+    }
+    modify {
+      yield &_i
+    }
+  }
+}
+
+@available(SwiftStdlib 9999, *)
+public func getNew() -> StructNew {
+  return StructNew(_i: 3)
+}
+
+@inlinable
+@available(SwiftStdlib 9999, *)
+@_silgen_name("readNewInlinableNew")
+public func readNewInlinableNew(_ n: StructNew) -> Int {
+// CHECK-LABEL: sil {{.*}}@readNewInlinableNew : {{.*}} {
+                  // function_ref StructNew.i.read2
+// CHECK:         function_ref @$s7Library9StructNewV1iSivy
+// CHECK-LABEL: } // end sil function 'readNewInlinableNew'
+  return n.i
+}
+
+@available(SwiftStdlib 9999, *)
+@_silgen_name("readNewNoninlinableNew")
+public func readNewNoninlinableNew(_ n: StructNew) -> Int {
+// CHECK-LABEL: sil {{.*}}@readNewNoninlinableNew : {{.*}} {
+                  // function_ref StructNew.i.read2
+// CHECK:         function_ref @$s7Library9StructNewV1iSivy
+// CHECK-LABEL: } // end sil function 'readNewNoninlinableNew'
+  return n.i
+}
+
+@inlinable
+@available(SwiftStdlib 9999, *)
+@_silgen_name("modifyNewInlinableNew")
+public func modifyNewInlinableNew(_ n: inout StructNew) {
+// CHECK-LABEL: sil {{.*}}@modifyNewInlinableNew : {{.*}} {
+                  // function_ref StructNew.i.modify2
+// CHECK:         function_ref @$s7Library9StructNewV1iSivx
+// CHECK-LABEL: } // end sil function 'modifyNewInlinableNew'
+  n.i.increment()
+}
+
+@available(SwiftStdlib 9999, *)
+@_silgen_name("modifyNewNoninlinableNew")
+public func modifyNewNoninlinableNew(_ n: inout StructNew) {
+// CHECK-LABEL: sil {{.*}}@modifyNewNoninlinableNew : {{.*}} {
+                  // function_ref StructNew.i.modify2
+// CHECK:         function_ref @$s7Library9StructNewV1iSivx
+// CHECK-LABEL: } // end sil function 'modifyNewNoninlinableNew'
+  n.i.increment()
+}
+
+public struct StructOld {
+  var _i: Int
+  public var i: Int {
+    read {
+      yield _i
+    }
+    modify {
+      yield &_i
+    }
+  }
+}
+
+public func getOld() -> StructOld {
+  return StructOld(_i: 3)
+}
+
+@inlinable
+@_silgen_name("readOldInlinableOld")
+public func readOldInlinableOld(_ n: StructOld) -> Int {
+// CHECK-LABEL: sil {{.*}}@readOldInlinableOld : {{.*}} {
+// Could be inlined into code that's running before CoroutineAccessors is
+// available--must use read.
+                  // function_ref StructOld.i.read
+// CHECK:         function_ref @$s7Library9StructOldV1iSivr
+// CHECK-LABEL: } // end sil function 'readOldInlinableOld'
+  return n.i
+}
+
+@_silgen_name("readOldNoninlinableOld")
+public func readOldNoninlinableOld(_ n: StructOld) -> Int {
+// CHECK-LABEL: sil {{.*}}@readOldNoninlinableOld : {{.*}} {
+// Opaque symbol never inlined.  Even though it was available before
+// CoroutineAccessors was, the implementation in this version of the module--can
+// use read2.
+                  // function_ref StructOld.i.read2
+// CHECK:         function_ref @$s7Library9StructOldV1iSivy
+// CHECK-LABEL: } // end sil function 'readOldNoninlinableOld'
+  return n.i
+}
+
+@inlinable
+@available(SwiftStdlib 9999, *)
+@_silgen_name("readOldInlinableNew")
+public func readOldInlinableNew(_ n: StructOld) -> Int {
+// CHECK-LABEL: sil {{.*}}@readOldInlinableNew : {{.*}} {
+// Could be inlined, but only into code that's running at or after
+// CoroutineAccessors is available--can use read2.
+                  // function_ref StructOld.i.read2
+// CHECK:         function_ref @$s7Library9StructOldV1iSivy
+// CHECK-LABEL: } // end sil function 'readOldInlinableNew'
+  return n.i
+}
+
+@available(SwiftStdlib 9999, *)
+@_silgen_name("readOldNoninlinableNew")
+public func readOldNoninlinableNew(_ n: StructOld) -> Int {
+// CHECK-LABEL: sil {{.*}}@readOldNoninlinableNew : {{.*}} {
+// Neither inlinable nor available before CoroutineAccessors--can use read2.
+                  // function_ref StructOld.i.read2
+// CHECK:         function_ref @$s7Library9StructOldV1iSivy
+// CHECK-LABEL: } // end sil function 'readOldNoninlinableNew'
+  return n.i
+}
+
+@inlinable
+@_silgen_name("modifyOldInlinableOld")
+public func modifyOldInlinableOld(_ n: inout StructOld) {
+// CHECK-LABEL: sil {{.*}}@modifyOldInlinableOld : {{.*}} {
+// Could be inlined into code that's running before CoroutineAccessors is
+// available--must use modify.
+                  // function_ref StructOld.i.modify
+// CHECK:         function_ref @$s7Library9StructOldV1iSivM
+// CHECK-LABEL: } // end sil function 'modifyOldInlinableOld'
+  n.i.increment()
+}
+
+@_silgen_name("modifyOldNoninlinableOld")
+public func modifyOldNoninlinableOld(_ n: inout StructOld) {
+// CHECK-LABEL: sil {{.*}}@modifyOldNoninlinableOld : {{.*}} {
+// Opaque symbol never inlined.  Even though it was available before
+// CoroutineAccessors was, the implementation in this version of the module--can
+// use modify2.
+                  // function_ref StructOld.i.modify2
+// CHECK:         function_ref @$s7Library9StructOldV1iSivx
+// CHECK-LABEL: } // end sil function 'modifyOldNoninlinableOld'
+  n.i.increment()
+}
+
+@inlinable
+@available(SwiftStdlib 9999, *)
+@_silgen_name("modifyOldInlinableNew")
+public func modifyOldInlinableNew(_ n: inout StructOld) {
+// CHECK-LABEL: sil {{.*}}@modifyOldInlinableNew : {{.*}} {
+// Could be inlined, but only into code that's running at or after
+// CoroutineAccessors is available--can use modify2.
+                  // function_ref StructOld.i.modify2
+// CHECK:         function_ref @$s7Library9StructOldV1iSivx
+// CHECK-LABEL: } // end sil function 'modifyOldInlinableNew'
+  n.i.increment()
+}
+
+@available(SwiftStdlib 9999, *)
+@_silgen_name("modifyOldNoninlinableNew")
+public func modifyOldNoninlinableNew(_ n: inout StructOld) {
+// CHECK-LABEL: sil {{.*}}@modifyOldNoninlinableNew : {{.*}} {
+// Neither inlinable nor available before CoroutineAccessors--can use modify2.
+                  // function_ref StructOld.i.modify2
+// CHECK:         function_ref @$s7Library9StructOldV1iSivx
+// CHECK-LABEL: } // end sil function 'modifyOldNoninlinableNew'
+  n.i.increment()
+}
+
+public func takeInt(_ i: Int) {
+}
+
+open class BaseClassOld {
+  public init(_ i : Int) {
+    self._i = i
+  }
+  var _i: Int
+  open var i: Int {
+    read {
+      yield _i
+    }
+    modify {
+      yield &_i
+    }
+  }
+}
+
+//--- Downstream.swift
+
+import Library
+
+@_silgen_name("readNewOld")
+func readNewOld() {
+// CHECK-LABEL: sil {{.*}}@readNewOld : {{.*}} {
+// Neither inlinable nor available before CoroutineAccessors--can use read2.
+                  // function_ref StructNew.i.read2
+// CHECK:         function_ref @$s7Library9StructNewV1iSivy
+// CHECK-LABEL: } // end sil function 'readNewOld'
+  if #available(SwiftStdlib 9999, *) {
+    let n = getNew()
+
+    let i = n.i
+  }
+}
+
+@available(SwiftStdlib 9999, *)
+@_silgen_name("readNewNew")
+func readNewNew() {
+// CHECK-LABEL: sil {{.*}}@readNewNew : {{.*}} {
+// Neither inlinable nor available before CoroutineAccessors--can use read2.
+                  // function_ref StructNew.i.read2
+// CHECK:         function_ref @$s7Library9StructNewV1iSivy
+// CHECK-LABEL: } // end sil function 'readNewNew'
+  let n = getNew()
+
+  let i = n.i
+}
+
+@available(SwiftStdlib 9999, *)
+@_silgen_name("readOldNew")
+func readOldNew() {
+// CHECK-LABEL: sil {{.*}}@readOldNew : {{.*}} {
+// Although this module could be back-deployed to before CoroutineAccessors were
+// available, it can only run in environments where the feature is available--
+// can use read2.
+                  // function_ref StructOld.i.read2
+// CHECK:         function_ref @$s7Library9StructOldV1iSivy
+// CHECK-LABEL: } // end sil function 'readOldNew'
+  let n = getOld()
+
+  let i = n.i
+}
+
+@_silgen_name("readOldOld")
+func readOldOld() {
+// CHECK-LABEL: sil {{.*}}@readOldOld : {{.*}} {
+// This module could be back-deployed to before CoroutineAccessors were
+// available, and nothing ensures the function is available only after the
+// feature is available--must use read.
+                  // function_ref StructOld.i.read
+// CHECK-OLD:     function_ref @$s7Library9StructOldV1iSivr
+// This module cannot be back-deployed (the deployment target is
+// available, and nothing ensures the function is available only after the
+// feature is available--must use read.
+                  // function_ref StructOld.i.read2
+// CHECK-NEW:     function_ref @$s7Library9StructOldV1iSivy
+// CHECK-LABEL: } // end sil function 'readOldOld'
+  let n = getOld()
+
+  let i = n.i
+}
+
+@_silgen_name("modifyNewOld")
+func modifyNewOld() {
+// CHECK-LABEL: sil {{.*}}@modifyNewOld : {{.*}} {
+// Neither inlinable nor available before CoroutineAccessors--can use modify2.
+                  // function_ref StructNew.i.modify2
+// CHECK:         function_ref @$s7Library9StructNewV1iSivx
+// CHECK-LABEL: } // end sil function 'modifyNewOld'
+  if #available(SwiftStdlib 9999, *) {
+    var n = getNew()
+
+    n.i.increment()
+  }
+}
+
+@available(SwiftStdlib 9999, *)
+@_silgen_name("modifyNewNew")
+func modifyNewNew() {
+// CHECK-LABEL: sil {{.*}}@modifyNewNew : {{.*}} {
+// Neither inlinable nor available before CoroutineAccessors--can use modify2.
+                  // function_ref StructNew.i.modify2
+// CHECK:         function_ref @$s7Library9StructNewV1iSivx
+// CHECK-LABEL: } // end sil function 'modifyNewNew'
+  var n = getNew()
+
+  n.i.increment()
+}
+
+@available(SwiftStdlib 9999, *)
+@_silgen_name("modifyOldNew")
+func modifyOldNew() {
+// CHECK-LABEL: sil {{.*}}@modifyOldNew : {{.*}} {
+// Although this module could be back-deployed to before CoroutineAccessors were
+// available, it can only run in environments where the feature is available--
+// can use modify2.
+                  // function_ref StructOld.i.modify2
+// CHECK:         function_ref @$s7Library9StructOldV1iSivx
+// CHECK-LABEL: } // end sil function 'modifyOldNew'
+  var n = getOld()
+
+  n.i.increment()
+}
+
+@_silgen_name("modifyOldOld")
+func modifyOldOld() {
+// CHECK-LABEL: sil {{.*}}@modifyOldOld : {{.*}} {
+// This module could be back-deployed to before CoroutineAccessors were
+// available, and nothing ensures the function is available only after the
+// feature is available--must use modify.
+                  // function_ref StructOld.i.modify
+// CHECK-OLD:     function_ref @$s7Library9StructOldV1iSivM
+// This module cannot be back-deployed (the deployment target is
+// available, and nothing ensures the function is available only after the
+// feature is available--must use modify.
+                  // function_ref StructOld.i.modify2
+// CHECK-NEW:     function_ref @$s7Library9StructOldV1iSivx
+// CHECK-LABEL: } // end sil function 'modifyOldOld'
+  var n = getOld()
+
+  n.i.increment()
+}
+
+public class DerivedOldFromBaseClassOld : BaseClassOld {
+  public init(_ i : Int, _ j : Int) {
+    self._j = j
+    super.init(i)
+  }
+  var _j: Int
+  override public var i: Int {
+    read {
+      yield _j
+    }
+    modify {
+      yield &_j
+    }
+  }
+}
+
+// CHECK-LABEL: sil_vtable [serialized] DerivedOldFromBaseClassOld {
+// CHECK-NEXT:    #BaseClassOld.init!allocator
+// CHECK-NEXT:    #BaseClassOld.i!read
+// CHECK-NEXT:    #BaseClassOld.i!read2
+// CHECK-NEXT:    #BaseClassOld.i!setter
+// CHECK-NEXT:    #BaseClassOld.i!modify
+// CHECK-NEXT:    #BaseClassOld.i!modify2
+// CHECK:       }
diff --git a/test/SILGen/coroutine_accessors_new_abi.swift b/test/SILGen/coroutine_accessors_new_abi.swift
new file mode 100644
index 0000000000000..c97de4b49a76c
--- /dev/null
+++ b/test/SILGen/coroutine_accessors_new_abi.swift
@@ -0,0 +1,22 @@
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types   \
+// RUN:     %s                                              \
+// RUN:     -enable-callee-allocated-coro-abi               \
+// RUN:     -enable-library-evolution                       \
+// RUN:     -enable-experimental-feature CoroutineAccessors \
+// RUN: | %FileCheck %s --check-prefixes=CHECK,CHECK-NORMAL
+
+// REQUIRES: swift_feature_CoroutineAccessors
+
+// CHECK: yield_once_2
+
+struct S {
+
+var one: Int = 1
+var i: Int {
+  read {
+    yield one
+  }
+}
+
+}
+
diff --git a/test/SILGen/coroutine_accessors_old_abi.swift b/test/SILGen/coroutine_accessors_old_abi.swift
new file mode 100644
index 0000000000000..cd7450e8535b4
--- /dev/null
+++ b/test/SILGen/coroutine_accessors_old_abi.swift
@@ -0,0 +1,22 @@
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types   \
+// RUN:     %s                                              \
+// RUN:     -disable-callee-allocated-coro-abi              \
+// RUN:     -enable-library-evolution                       \
+// RUN:     -enable-experimental-feature CoroutineAccessors \
+// RUN: | %FileCheck %s --check-prefixes=CHECK,CHECK-NORMAL
+
+// REQUIRES: swift_feature_CoroutineAccessors
+
+// CHECK: yield_once
+// CHECK-NOT: yield_once_2
+
+struct S {
+
+var zero: Int = 0
+var i: Int {
+  read {
+    yield zero
+  }
+}
+
+}
diff --git a/test/SILGen/coroutine_accessors_skip.swift b/test/SILGen/coroutine_accessors_skip.swift
index d5717302be901..a057ac92e1272 100644
--- a/test/SILGen/coroutine_accessors_skip.swift
+++ b/test/SILGen/coroutine_accessors_skip.swift
@@ -1,5 +1,6 @@
 // RUN: %target-swift-emit-silgen                            \
 // RUN:     %s                                               \
+// RUN:     -enable-callee-allocated-coro-abi                \
 // RUN:     -experimental-skip-non-inlinable-function-bodies \
 // RUN:     -enable-library-evolution                        \
 // RUN:     -enable-experimental-feature CoroutineAccessors  \
@@ -7,6 +8,7 @@
 
 // RUN: %target-swift-emit-silgen                                              \
 // RUN:     %s                                                                 \
+// RUN:     -enable-callee-allocated-coro-abi                                  \
 // RUN:     -experimental-skip-non-inlinable-function-bodies                   \
 // RUN:     -enable-library-evolution                                          \
 // RUN:     -enable-experimental-feature CoroutineAccessors                    \
diff --git a/test/SILGen/default_override.swift b/test/SILGen/default_override.swift
index f2d74d2bf6ba8..f3db5b64847b0 100644
--- a/test/SILGen/default_override.swift
+++ b/test/SILGen/default_override.swift
@@ -1,5 +1,6 @@
 // RUN: %target-swift-emit-silgen                           \
 // RUN:     %s                                              \
+// RUN:     -enable-callee-allocated-coro-abi               \
 // RUN:     -enable-library-evolution                       \
 // RUN:     -enable-experimental-feature BuiltinModule      \
 // RUN:     -enable-experimental-feature CoroutineAccessors \
@@ -7,6 +8,7 @@
 
 // RUN: %target-swift-emit-silgen                           \
 // RUN:     %s                                              \
+// RUN:     -enable-callee-allocated-coro-abi               \
 // RUN:     -enable-experimental-feature BuiltinModule      \
 // RUN:     -enable-experimental-feature CoroutineAccessors \
 // RUN: | %FileCheck %s --check-prefix=CHECK-FRAGILE
diff --git a/test/SILGen/dependency_through_closure.swift b/test/SILGen/dependency_through_closure.swift
new file mode 100644
index 0000000000000..3ee337ad08dec
--- /dev/null
+++ b/test/SILGen/dependency_through_closure.swift
@@ -0,0 +1,23 @@
+// RUN: %target-swift-emit-silgen -verify -enable-experimental-feature Lifetimes -enable-experimental-feature AddressableTypes %s
+
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_AddressableTypes
+
+@_addressableForDependencies
+struct Owner {
+    @_lifetime(borrow self)
+    func reference() -> Reference { fatalError() }
+}
+
+struct Reference: ~Escapable {
+    @_lifetime(immortal)
+    init() { fatalError() }
+
+    func use() {}
+}
+
+func closure(_: () -> Void) {}
+
+func dependencyThroughClosure(from owner: borrowing Owner) {
+    closure { owner.reference().use() }
+}
diff --git a/test/SILGen/diagnose_implicit_raw_conversion.swift b/test/SILGen/diagnose_implicit_raw_conversion.swift
index a26dac6732aa1..6de2cd9d030eb 100644
--- a/test/SILGen/diagnose_implicit_raw_conversion.swift
+++ b/test/SILGen/diagnose_implicit_raw_conversion.swift
@@ -45,10 +45,10 @@ func test_errors<T>(arg: T, sarg: String, anyBCArg: BitwiseCopyable) {
     readBytes(&array)     // expected-warning {{forming 'UnsafeRawPointer' to a variable of type '[T]'; this is likely incorrect because 'T' may contain an object reference.}}
     writeBytes(&array)  // expected-warning {{forming 'UnsafeMutableRawPointer' to a variable of type '[T]'; this is likely incorrect because 'T' may contain an object reference.}}
 
-    read_char(&array)   // expected-warning {{forming 'UnsafePointer<Int8>' to a variable of type 'Array<T>'; this is likely incorrect because 'T' may contain an object reference.}}
-    write_char(&array)  // expected-warning {{forming 'UnsafeMutablePointer<Int8>' to a variable of type 'Array<T>'; this is likely incorrect because 'T' may contain an object reference.}}
-    read_uchar(&array)  // expected-warning {{forming 'UnsafePointer<UInt8>' to a variable of type 'Array<T>'; this is likely incorrect because 'T' may contain an object reference.}}
-    write_uchar(&array) // expected-warning {{forming 'UnsafeMutablePointer<UInt8>' to a variable of type 'Array<T>'; this is likely incorrect because 'T' may contain an object reference.}}
+    read_char(&array)   // expected-warning {{forming 'UnsafePointer<CChar>' (aka 'UnsafePointer<Int8>') to a variable of type '[T]'; this is likely incorrect because 'T' may contain an object reference.}}
+    write_char(&array)  // expected-warning {{forming 'UnsafeMutablePointer<CChar>' (aka 'UnsafeMutablePointer<Int8>') to a variable of type '[T]'; this is likely incorrect because 'T' may contain an object reference.}}
+    read_uchar(&array)  // expected-warning {{forming 'UnsafePointer<UInt8>' to a variable of type '[T]'; this is likely incorrect because 'T' may contain an object reference.}}
+    write_uchar(&array) // expected-warning {{forming 'UnsafeMutablePointer<UInt8>' to a variable of type '[T]'; this is likely incorrect because 'T' may contain an object reference.}}
 
     var anyBC: BitwiseCopyable = anyBCArg
     readBytes(&anyBC)   // expected-warning {{forming 'UnsafeRawPointer' to a variable of type 'any BitwiseCopyable'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
@@ -67,10 +67,10 @@ func test_errors<T>(arg: T, sarg: String, anyBCArg: BitwiseCopyable) {
     readBytes(&bcArray)     // expected-warning {{forming 'UnsafeRawPointer' to a variable of type '[any BitwiseCopyable]'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
     writeBytes(&bcArray)  // expected-warning {{forming 'UnsafeMutableRawPointer' to a variable of type '[any BitwiseCopyable]'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
 
-    read_char(&bcArray)   // expected-warning {{forming 'UnsafePointer<Int8>' to a variable of type 'Array<any BitwiseCopyable>'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
-    write_char(&bcArray)  // expected-warning {{forming 'UnsafeMutablePointer<Int8>' to a variable of type 'Array<any BitwiseCopyable>'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
-    read_uchar(&bcArray)  // expected-warning {{forming 'UnsafePointer<UInt8>' to a variable of type 'Array<any BitwiseCopyable>'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
-    write_uchar(&bcArray) // expected-warning {{forming 'UnsafeMutablePointer<UInt8>' to a variable of type 'Array<any BitwiseCopyable>'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
+    read_char(&bcArray)   // expected-warning {{forming 'UnsafePointer<CChar>' (aka 'UnsafePointer<Int8>') to a variable of type '[any BitwiseCopyable]'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
+    write_char(&bcArray)  // expected-warning {{forming 'UnsafeMutablePointer<CChar>' (aka 'UnsafeMutablePointer<Int8>') to a variable of type '[any BitwiseCopyable]'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
+    read_uchar(&bcArray)  // expected-warning {{forming 'UnsafePointer<UInt8>' to a variable of type '[any BitwiseCopyable]'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
+    write_uchar(&bcArray) // expected-warning {{forming 'UnsafeMutablePointer<UInt8>' to a variable of type '[any BitwiseCopyable]'; this is likely incorrect because 'any BitwiseCopyable' may contain an object reference.}}
 
     var string: String = sarg
     readBytes(&string)   // expected-warning {{forming 'UnsafeRawPointer' to an inout variable of type String exposes the internal representation rather than the string contents.}}
diff --git a/test/SILGen/dynamic_self.swift b/test/SILGen/dynamic_self.swift
index 540699b1507ee..f69ec350f9511 100644
--- a/test/SILGen/dynamic_self.swift
+++ b/test/SILGen/dynamic_self.swift
@@ -1,10 +1,12 @@
-// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -swift-version 4 %s -disable-objc-attr-requires-foundation-module -enable-objc-interop | %FileCheck %s
-// RUN: %target-swift-emit-sil -Xllvm -sil-print-types -swift-version 4 -O %s -disable-objc-attr-requires-foundation-module -enable-objc-interop
-// RUN: %target-swift-emit-ir -swift-version 4 %s -disable-objc-attr-requires-foundation-module -enable-objc-interop
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -swift-version 4 -enable-upcoming-feature ImmutableWeakCaptures %s -disable-objc-attr-requires-foundation-module -enable-objc-interop | %FileCheck %s
+// RUN: %target-swift-emit-sil -Xllvm -sil-print-types -swift-version 4 -O -enable-upcoming-feature ImmutableWeakCaptures %s -disable-objc-attr-requires-foundation-module -enable-objc-interop
+// RUN: %target-swift-emit-ir -swift-version 4 -enable-upcoming-feature ImmutableWeakCaptures %s -disable-objc-attr-requires-foundation-module -enable-objc-interop
 
-// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -swift-version 5 %s -disable-objc-attr-requires-foundation-module -enable-objc-interop | %FileCheck %s
-// RUN: %target-swift-emit-sil -Xllvm -sil-print-types -swift-version 5 -O %s -disable-objc-attr-requires-foundation-module -enable-objc-interop
-// RUN: %target-swift-emit-ir -swift-version 5 %s -disable-objc-attr-requires-foundation-module -enable-objc-interop
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -swift-version 5 -enable-upcoming-feature ImmutableWeakCaptures %s -disable-objc-attr-requires-foundation-module -enable-objc-interop | %FileCheck %s
+// RUN: %target-swift-emit-sil -Xllvm -sil-print-types -swift-version 5 -O -enable-upcoming-feature ImmutableWeakCaptures %s -disable-objc-attr-requires-foundation-module -enable-objc-interop
+// RUN: %target-swift-emit-ir -swift-version 5 -enable-upcoming-feature ImmutableWeakCaptures %s -disable-objc-attr-requires-foundation-module -enable-objc-interop
+
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 protocol P {
   func f() -> Self
@@ -67,7 +69,7 @@ func testDynamicSelfDispatchGeneric(gy: GY<Int>) {
   // CHECK: bb0([[GY:%[0-9]+]] : @guaranteed $GY<Int>):
   // CHECK:   [[GY_AS_GX:%[0-9]+]] = upcast [[GY]] : $GY<Int> to $GX<Array<Int>>
   // CHECK:   [[GX_F:%[0-9]+]] = class_method [[GY_AS_GX]] : $GX<Array<Int>>, #GX.f : <T> (GX<T>) -> () -> @dynamic_self GX<T>, $@convention(method) <τ_0_0> (@guaranteed GX<τ_0_0>) -> @owned GX<τ_0_0>
-  // CHECK:   [[GX_RESULT:%[0-9]+]] = apply [[GX_F]]<[Int]>([[GY_AS_GX]]) : $@convention(method) <τ_0_0> (@guaranteed GX<τ_0_0>) -> @owned GX<τ_0_0>
+  // CHECK:   [[GX_RESULT:%[0-9]+]] = apply [[GX_F]]<Array<Int>>([[GY_AS_GX]]) : $@convention(method) <τ_0_0> (@guaranteed GX<τ_0_0>) -> @owned GX<τ_0_0>
   // CHECK:   [[GY_RESULT:%[0-9]+]] = unchecked_ref_cast [[GX_RESULT]] : $GX<Array<Int>> to $GY<Int>
   // CHECK:   destroy_value [[GY_RESULT]] : $GY<Int>
   _ = gy.f()
diff --git a/test/SILGen/dynamic_self_as_lvalue_base.swift b/test/SILGen/dynamic_self_as_lvalue_base.swift
new file mode 100644
index 0000000000000..25c3bf4542a18
--- /dev/null
+++ b/test/SILGen/dynamic_self_as_lvalue_base.swift
@@ -0,0 +1,32 @@
+// RUN: %target-swift-emit-silgen %s
+
+class C: P1, P2 {
+  public func f(_ n: Int) -> Self {
+    self.x = n
+    self.y = n
+    self.z = n
+    return self
+  }
+
+  public var x: Int? {
+    get { fatalError() }
+    set { }
+  }
+}
+
+protocol P1: AnyObject {}
+protocol P2 {}
+
+extension P1 {
+  public var y: Int? {
+    get { fatalError() }
+    set { }
+  }
+}
+
+extension P2 {
+  public var z: Int? {
+    get { fatalError() }
+    nonmutating set { }
+  }
+}
diff --git a/test/SILGen/dynamic_self_cast.swift b/test/SILGen/dynamic_self_cast.swift
index 15b3eb8f4c4d1..468cab194fa51 100644
--- a/test/SILGen/dynamic_self_cast.swift
+++ b/test/SILGen/dynamic_self_cast.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -Xllvm -sil-print-types -emit-silgen %s | %FileCheck %s
+// RUN: %target-swift-frontend -Xllvm -sil-print-types -disable-objc-interop -emit-silgen %s | %FileCheck %s
 
 public class SelfCasts {
   // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC02toD0yACXDACFZ : $@convention(method) (@guaranteed SelfCasts, @thick SelfCasts.Type) -> @owned SelfCasts {
@@ -31,7 +31,7 @@ public class SelfCasts {
   }
 
   // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC016classGenericFromD0xyRlzClFZ : $@convention(method) <T where T : AnyObject> (@thick SelfCasts.Type) -> @owned T
-  // CHECK: unconditional_checked_cast_addr @dynamic_self SelfCasts in {{.*}} : $*SelfCasts to T in {{.*}} : $*T
+  // CHECK: unconditional_checked_cast {{.*}} : $SelfCasts to T
   // CHECK: }
   public static func classGenericFromSelf<T : AnyObject>() -> T {
     let s = Self()
@@ -68,7 +68,7 @@ public class SelfCasts {
   }
 
   // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC016classGenericFromD11ConditionalxSgyRlzClFZ : $@convention(method) <T where T : AnyObject> (@thick SelfCasts.Type) -> @owned Optional<T> {
-  // CHECK: checked_cast_addr_br take_always @dynamic_self SelfCasts in {{.*}} : $*SelfCasts to T in {{.*}} : $*T
+  // CHECK: checked_cast_br @dynamic_self SelfCasts in {{.*}} : $SelfCasts to T
   // CHECK: }
   public static func classGenericFromSelfConditional<T : AnyObject>() -> T? {
     let s = Self()
diff --git a/test/SILGen/dynamic_self_cast_objc.swift b/test/SILGen/dynamic_self_cast_objc.swift
new file mode 100644
index 0000000000000..a4b09105f1061
--- /dev/null
+++ b/test/SILGen/dynamic_self_cast_objc.swift
@@ -0,0 +1,82 @@
+// RUN: %target-swift-frontend -Xllvm -sil-print-types -module-name=dynamic_self_cast -emit-silgen %s | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+public class SelfCasts {
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC02toD0yACXDACFZ : $@convention(method) (@guaranteed SelfCasts, @thick SelfCasts.Type) -> @owned SelfCasts {
+  // CHECK: unconditional_checked_cast {{.*}} : $SelfCasts to @dynamic_self SelfCasts
+  // CHECK: }
+  public static func toSelf(_ s: SelfCasts) -> Self {
+    return s as! Self
+  }
+
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC09genericToD0yACXDxlFZ : $@convention(method) <T> (@in_guaranteed T, @thick SelfCasts.Type) -> @owned SelfCasts {
+  // CHECK: unconditional_checked_cast_addr T in {{.*}} : $*T to @dynamic_self SelfCasts in {{.*}} : $*SelfCasts
+  // CHECK: }
+  public static func genericToSelf<T>(_ s: T) -> Self {
+    return s as! Self
+  }
+
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC014classGenericToD0yACXDxRlzClFZ : $@convention(method) <T where T : AnyObject> (@guaranteed T, @thick SelfCasts.Type) -> @owned SelfCasts {
+  // CHECK: unconditional_checked_cast {{.*}} : $T to @dynamic_self SelfCasts
+  // CHECK: }
+  public static func classGenericToSelf<T : AnyObject>(_ s: T) -> Self {
+    return s as! Self
+  }
+
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC011genericFromD0xylFZ : $@convention(method) <T> (@thick SelfCasts.Type) -> @out T {
+  // CHECK: unconditional_checked_cast_addr @dynamic_self SelfCasts in {{.*}} : $*SelfCasts to T in {{.*}} : $*T
+  // CHECK: }
+  public static func genericFromSelf<T>() -> T {
+    let s = Self()
+    return s as! T
+  }
+
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC016classGenericFromD0xyRlzClFZ : $@convention(method) <T where T : AnyObject> (@thick SelfCasts.Type) -> @owned T
+  // CHECK: unconditional_checked_cast_addr @dynamic_self SelfCasts in {{.*}} : $*SelfCasts to T in {{.*}} : $*T
+  // CHECK: }
+  public static func classGenericFromSelf<T : AnyObject>() -> T {
+    let s = Self()
+    return s as! T
+  }
+
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC02toD11ConditionalyACXDSgACFZ : $@convention(method) (@guaranteed SelfCasts, @thick SelfCasts.Type) -> @owned Optional<SelfCasts> {
+  // CHECK: checked_cast_br SelfCasts in {{.*}} : $SelfCasts to @dynamic_self SelfCasts
+  // CHECK: }
+  public static func toSelfConditional(_ s: SelfCasts) -> Self? {
+    return s as? Self
+  }
+
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC09genericToD11ConditionalyACXDSgxlFZ : $@convention(method) <T> (@in_guaranteed T, @thick SelfCasts.Type) -> @owned Optional<SelfCasts> {
+  // CHECK: checked_cast_addr_br take_always T in {{.*}} : $*T to @dynamic_self SelfCasts in {{.*}} : $*SelfCasts
+  // CHECK: }
+  public static func genericToSelfConditional<T>(_ s: T) -> Self? {
+    return s as? Self
+  }
+
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC014classGenericToD11ConditionalyACXDSgxRlzClFZ : $@convention(method) <T where T : AnyObject> (@guaranteed T, @thick SelfCasts.Type) -> @owned Optional<SelfCasts> {
+  // CHECK: checked_cast_br T in {{.*}} : $T to @dynamic_self SelfCasts
+  // CHECK: }
+  public static func classGenericToSelfConditional<T : AnyObject>(_ s: T) -> Self? {
+    return s as? Self
+  }
+
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC011genericFromD11ConditionalxSgylFZ : $@convention(method) <T> (@thick SelfCasts.Type) -> @out Optional<T> {
+  // CHECK: checked_cast_addr_br take_always @dynamic_self SelfCasts in {{.*}} : $*SelfCasts to T in {{.*}} : $*T
+  // CHECK: }
+  public static func genericFromSelfConditional<T>() -> T? {
+    let s = Self()
+    return s as? T
+  }
+
+  // CHECK-LABEL: sil [ossa] @$s17dynamic_self_cast9SelfCastsC016classGenericFromD11ConditionalxSgyRlzClFZ : $@convention(method) <T where T : AnyObject> (@thick SelfCasts.Type) -> @owned Optional<T> {
+  // CHECK: checked_cast_addr_br take_always @dynamic_self SelfCasts in {{.*}} : $*SelfCasts to T in {{.*}} : $*T
+  // CHECK: }
+  public static func classGenericFromSelfConditional<T : AnyObject>() -> T? {
+    let s = Self()
+    return s as? T
+  }
+
+  public required init() {}
+}
+
diff --git a/test/SILGen/dynamic_self_opened_existential.swift b/test/SILGen/dynamic_self_opened_existential.swift
new file mode 100644
index 0000000000000..a5ec8128197ea
--- /dev/null
+++ b/test/SILGen/dynamic_self_opened_existential.swift
@@ -0,0 +1,25 @@
+// RUN: %target-swift-emit-silgen %s
+
+public class C {
+  public func f() -> Self { return self }
+  public var v: Self { return self }
+  public subscript() -> Self { return self }
+
+  public func g1() {}
+}
+
+public protocol P {
+  func g2()
+}
+
+func f(_ p: any P & C) {
+  p.f().g1()
+  p.f().g2()
+
+  p.v.g1()
+  p.v.g2()
+
+  p[].g1()
+  p[].g2()
+}
+
diff --git a/test/SILGen/dynamic_self_opened_existential_2.swift b/test/SILGen/dynamic_self_opened_existential_2.swift
new file mode 100644
index 0000000000000..de330bc8f7966
--- /dev/null
+++ b/test/SILGen/dynamic_self_opened_existential_2.swift
@@ -0,0 +1,18 @@
+// RUN: %target-swift-emit-silgen %s
+
+class AA {
+  subscript<T>(_: T.Type) -> T? {
+    get { fatalError() }
+    set {}
+  }
+}
+
+class C {
+  typealias A = AA
+
+  func f() {
+    let a = AA()
+    guard let result = a[Self.A.self] else { return }
+    _ = result
+  }
+}
diff --git a/test/SILGen/dynamic_self_substitution.swift b/test/SILGen/dynamic_self_substitution.swift
new file mode 100644
index 0000000000000..2656f0770652a
--- /dev/null
+++ b/test/SILGen/dynamic_self_substitution.swift
@@ -0,0 +1,29 @@
+// RUN: %target-swift-emit-silgen %s
+
+class C {
+  func f1() -> Self? {
+    return D<Self>().g(self)
+  }
+
+  func f2() -> Self? {
+    return D<Self>()[self]
+  }
+
+  func f3() -> Self? {
+    return D<Self>().x
+  }
+}
+
+class D<T> {
+  func g(_ t: T) -> T? {
+    return t
+  }
+
+  subscript(_ t: T) -> T? {
+    return t
+  }
+
+  var x: T? {
+    fatalError()
+  }
+}
diff --git a/test/SILGen/emplace.swift b/test/SILGen/emplace.swift
new file mode 100644
index 0000000000000..8096edc8447b2
--- /dev/null
+++ b/test/SILGen/emplace.swift
@@ -0,0 +1,93 @@
+// RUN: %target-swift-frontend -enable-experimental-feature BuiltinModule -emit-silgen %s | %FileCheck %s
+
+// REQUIRES: swift_feature_BuiltinModule
+
+import Builtin
+
+@_silgen_name("do_emplace")
+func do_emplace(_: Builtin.RawPointer)
+
+struct AO {
+    var x: Any
+}
+
+struct Loadable {
+    var x: AnyObject
+}
+
+// CHECK-LABEL: sil {{.*}} @$s{{.*}}_in_place_loadable
+func emplace_in_place_loadable() -> Loadable {
+    // CHECK: [[TMP:%.*]] = alloc_stack $Loadable
+    // CHECK-NEXT: builtin "prepareInitialization"([[TMP]])
+    // CHECK-NEXT: [[PTR:%.*]] = address_to_pointer {{.*}} [[TMP]]
+    // CHECK-NEXT: apply {{.*}}([[PTR]])
+    // CHECK-NEXT: load [take] [[TMP]]
+    // CHECK-NEXT: dealloc_stack [[TMP]]
+    return Builtin.emplace(do_emplace)
+}
+
+// CHECK-LABEL: sil {{.*}} @$s{{.*}}_in_place_ao
+// CHECK: bb0([[OUT:%.*]] : $*AO):
+func emplace_in_place_ao() -> AO {
+    // CHECK: builtin "prepareInitialization"([[OUT]])
+    // CHECK-NEXT: [[PTR:%.*]] = address_to_pointer {{.*}} [[OUT]]
+    // CHECK-NEXT: apply [[FN:%.*]]([[PTR]])
+    // CHECK-NEXT: destroy_value [[FN]]
+    // CHECK-NEXT: tuple ()
+    // CHECK-NEXT: return
+    return Builtin.emplace(do_emplace)
+}
+
+// CHECK-LABEL: sil {{.*}} @$s{{.*}}_assign_loadable
+// CHECK: bb0([[INOUT:%.*]] : $*Loadable):
+func emplace_assign_loadable(_ x: inout Loadable) {
+    // CHECK: [[TMP:%.*]] = alloc_stack $Loadable
+    // CHECK-NEXT: builtin "prepareInitialization"([[TMP]])
+    // CHECK-NEXT: [[PTR:%.*]] = address_to_pointer {{.*}} [[TMP]]
+    // CHECK-NEXT: apply {{.*}}([[PTR]])
+    // CHECK-NEXT: [[RESULT:%.*]] = load [take] [[TMP]]
+    // CHECK-NEXT: [[WRITE:%.*]] = begin_access [modify] [unknown] [[INOUT]]
+    // CHECK-NEXT: assign [[RESULT]] to [[WRITE]]
+    // CHECK-NEXT: end_access [[WRITE]]
+    // CHECK-NEXT: dealloc_stack [[TMP]]
+    x = Builtin.emplace(do_emplace)
+}
+
+// CHECK-LABEL: sil {{.*}} @$s{{.*}}_assign_ao
+// CHECK: bb0([[INOUT:%.*]] : $*AO):
+func emplace_assign_ao(_ x: inout AO) {
+    // CHECK: [[TMP:%.*]] = alloc_stack $AO
+    // CHECK-NEXT: builtin "prepareInitialization"([[TMP]])
+    // CHECK-NEXT: [[PTR:%.*]] = address_to_pointer {{.*}} [[TMP]]
+    // CHECK-NEXT: apply {{.*}}([[PTR]])
+    // CHECK-NEXT: [[WRITE:%.*]] = begin_access [modify] [unknown] [[INOUT]]
+    // CHECK-NEXT: copy_addr [take] [[TMP]] to [[WRITE]]
+    // CHECK-NEXT: end_access [[WRITE]]
+    // CHECK-NEXT: dealloc_stack [[TMP]]
+    x = Builtin.emplace(do_emplace)
+}
+
+// CHECK-LABEL: sil {{.*}} @$s{{.*}}_ignore_loadable
+func emplace_ignore_loadable() {
+    // CHECK: [[TMP:%.*]] = alloc_stack $Loadable
+    // CHECK-NEXT: builtin "prepareInitialization"([[TMP]])
+    // CHECK-NEXT: [[PTR:%.*]] = address_to_pointer {{.*}} [[TMP]]
+    // CHECK-NEXT: apply {{.*}}([[PTR]])
+    // CHECK-NEXT: [[RESULT:%.*]] = load [take] [[TMP]]
+    // CHECK-NEXT: ignored_use [[RESULT]]
+    // CHECK-NEXT: destroy_value [[RESULT]]
+    // CHECK-NEXT: dealloc_stack [[TMP]]
+    let _: Loadable = Builtin.emplace(do_emplace)
+}
+
+// CHECK-LABEL: sil {{.*}} @$s{{.*}}_ignore_ao
+func emplace_ignore_ao() {
+    // CHECK: [[TMP:%.*]] = alloc_stack $AO
+    // CHECK-NEXT: builtin "prepareInitialization"([[TMP]])
+    // CHECK-NEXT: [[PTR:%.*]] = address_to_pointer {{.*}} [[TMP]]
+    // CHECK-NEXT: apply {{.*}}([[PTR]])
+    // CHECK-NEXT: ignored_use [[TMP]]
+    // CHECK-NEXT: destroy_addr [[TMP]]
+    // CHECK-NEXT: dealloc_stack [[TMP]]
+    let _: AO = Builtin.emplace(do_emplace)
+}
diff --git a/test/SILGen/execution_attr.swift b/test/SILGen/execution_attr.swift
index a5682dede74ae..63dc3f0aac675 100644
--- a/test/SILGen/execution_attr.swift
+++ b/test/SILGen/execution_attr.swift
@@ -1,40 +1,39 @@
-// RUN: %target-swift-emit-silgen %s -enable-experimental-feature ExecutionAttribute | %FileCheck -check-prefix CHECK -check-prefix DISABLED %s
-// RUN: %target-swift-emit-silgen %s -enable-experimental-feature ExecutionAttribute -enable-experimental-feature AsyncCallerExecution | %FileCheck -check-prefix CHECK -check-prefix ENABLED %s
+// RUN: %target-swift-emit-silgen %s  | %FileCheck -check-prefix CHECK -check-prefix DISABLED %s
+// RUN: %target-swift-emit-silgen %s -enable-upcoming-feature NonisolatedNonsendingByDefault | %FileCheck -check-prefix CHECK -check-prefix ENABLED %s
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_ExecutionAttribute
-// REQUIRES: swift_feature_AsyncCallerExecution
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 // Validate that both with and without the experimental flag we properly codegen
-// execution(caller) and execution(concurrent).
+// `@concurrent` and `nonisolated(nonsending)`
 
 // CHECK-LABEL: // executionCaller()
 // CHECK-NEXT: // Isolation: caller_isolation_inheriting
 // CHECK-NEXT: sil hidden [ossa] @$s14execution_attr0A6CalleryyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> () {
-@execution(caller)
+nonisolated(nonsending)
 func executionCaller() async {}
 
 // CHECK-LABEL: // executionConcurrent()
 // CHECK: // Isolation: nonisolated
 // CHECK: sil hidden [ossa] @$s14execution_attr0A10ConcurrentyyYaF : $@convention(thin) @async () -> () {
-@execution(concurrent)
+@concurrent
 func executionConcurrent() async {}
 
 // DISABLED: sil hidden [ossa] @$s14execution_attr0A15CallerParameteryyyyYaYCXEYaF : $@convention(thin) @async (@guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
 // ENABLED: sil hidden [ossa] @$s14execution_attr0A15CallerParameteryyyyYaYCXEYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()) -> () {
 // CHECK: } // end sil function '$s14execution_attr0A15CallerParameteryyyyYaYCXEYaF'
-func executionCallerParameter(_ x: @execution(caller) () async -> ()) async {
+func executionCallerParameter(_ x: nonisolated(nonsending) () async -> ()) async {
   await x()
 }
 
 // DISABLED-LABEL: sil hidden [ossa] @$s14execution_attr0A19ConcurrentParameteryyyyYaXEYaF : $@convention(thin) @async (@guaranteed @noescape @async @callee_guaranteed () -> ()) -> () {
 // ENABLED-LABEL: sil hidden [ossa] @$s14execution_attr0A19ConcurrentParameteryyyyYaXEYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @noescape @async @callee_guaranteed () -> ()) -> () {
-func executionConcurrentParameter(_ x: @execution(concurrent) () async -> ()) async {
+func executionConcurrentParameter(_ x: @concurrent () async -> ()) async {
   await x()
 }
 
 struct S {
-  let field: @execution(caller) () async -> ()
+  let field: nonisolated(nonsending) () async -> ()
 }
 
 // DISABLED: sil hidden [ossa] @$s14execution_attr0A11CallerFieldyyAA1SVYaF : $@convention(thin) @async (@guaranteed S) -> () {
@@ -61,5 +60,38 @@ extension S {
   // CHECK-LABEL: // S.executionCallerFieldMethod(_:)
   // CHECK: // Isolation: unspecified
   // CHECK: sil hidden [ossa] @$s14execution_attr1SV0A17CallerFieldMethodyyyyYaYCXEF : $@convention(method) (@guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> (), @guaranteed S) -> () {
-  func executionCallerFieldMethod(_ x: @execution(caller) () async -> ()) {}
+  func executionCallerFieldMethod(_ x: nonisolated(nonsending) () async -> ()) {}
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s14execution_attr24testWithDynamicIsolation2fnyyyYAXE_tYaF : $@convention(thin) @async (@guaranteed @isolated(any) @noescape @callee_guaranteed () -> ()) -> () {
+// CHECK: bb0([[PARAM_FN:%.*]] : @guaranteed $@isolated(any) @noescape @callee_guaranteed () -> ()):
+// CHECK:   [[GENERIC_EXEC:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+// CHECK-NEXT:   hop_to_executor [[GENERIC_EXEC]]
+// CHECK-NEXT:   [[FN:%.*]] = copy_value [[PARAM_FN]]
+// CHECK-NEXT:   [[BORROWED_FN:%.*]] = begin_borrow [[FN]]
+// CHECK-NEXT:   [[FN_ISOLATION:%.*]] = function_extract_isolation [[BORROWED_FN]]
+// CHECK-NEXT:   hop_to_executor [[FN_ISOLATION]]
+// CHECK-NEXT:   [[BORROWED_FN:%.*]] = begin_borrow [[FN]]
+// CHECK-NEXT:   apply [[BORROWED_FN]]()
+// CHECK: hop_to_executor [[GENERIC_EXEC]]
+// CHECK: } // end sil function '$s14execution_attr24testWithDynamicIsolation2fnyyyYAXE_tYaF'
+@concurrent
+func testWithDynamicIsolation(fn: @isolated(any) () -> Void) async {
+  await fn()
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s14execution_attr38testCallerIsolatedWithDynamicIsolation2fnyyyYAXE_tYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed @isolated(any) @noescape @callee_guaranteed () -> ()) -> () {
+// CHECK: bb0([[ISOLATION:%.*]] : @guaranteed $Optional<any Actor>, [[PARAM_FN:%.*]] : @guaranteed $@isolated(any) @noescape @callee_guaranteed () -> ()):
+// CHECK:   hop_to_executor [[ISOLATION]]
+// CHECK-NEXT:   [[FN:%.*]] = copy_value [[PARAM_FN]]
+// CHECK-NEXT:   [[BORROWED_FN:%.*]] = begin_borrow [[FN]]
+// CHECK-NEXT:   [[FN_ISOLATION:%.*]] = function_extract_isolation [[BORROWED_FN]]
+// CHECK-NEXT:   hop_to_executor [[FN_ISOLATION]]
+// CHECK-NEXT:   [[BORROWED_FN:%.*]] = begin_borrow [[FN]]
+// CHECK-NEXT:   apply [[BORROWED_FN]]()
+// CHECK: hop_to_executor [[ISOLATION]]
+// CHECK: } // end sil function '$s14execution_attr38testCallerIsolatedWithDynamicIsolation2fnyyyYAXE_tYaF'
+nonisolated(nonsending)
+func testCallerIsolatedWithDynamicIsolation(fn: @isolated(any) () -> Void) async {
+  await fn()
 }
diff --git a/test/SILGen/existential_erasure_length_2.swift b/test/SILGen/existential_erasure_length_2.swift
new file mode 100644
index 0000000000000..9c1e981caf1f0
--- /dev/null
+++ b/test/SILGen/existential_erasure_length_2.swift
@@ -0,0 +1,25 @@
+// RUN: %target-swift-emit-silgen %s
+
+protocol N {
+  associatedtype A: N
+}
+
+protocol P<A> {
+  associatedtype A: N
+  associatedtype B
+
+  func f0(_: A) -> B
+  func f1(_: A.A) -> B
+  func f2(_: A.A.A) -> B
+}
+
+struct G<T>: N {
+  typealias A = G<G<T>>
+}
+
+func call(x: any P<G<Int>>) -> (Any, Any, Any) {
+  let y0 = x.f0(G<Int>())
+  let y1 = x.f1(G<G<Int>>())
+  let y2 = x.f2(G<G<G<Int>>>())
+  return (y0, y1, y2)
+}
diff --git a/test/SILGen/existential_member_accesses_self_assoctype.swift b/test/SILGen/existential_member_accesses_self_assoctype.swift
index 0bb95a4979cb5..09237c6d2a26f 100644
--- a/test/SILGen/existential_member_accesses_self_assoctype.swift
+++ b/test/SILGen/existential_member_accesses_self_assoctype.swift
@@ -320,7 +320,7 @@ func testCovariantSelfSubscript8(p: any P) {
 // CHECK: [[LET:%[0-9]+]] = alloc_stack [lexical] [var_decl] $Any, let, name "x"
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocMethod1 : <Self where Self : P> (Self) -> () -> Self.A
-// CHECK: [[DEST:%[0-9]+]] = init_existential_addr [[LET]] : $*Any, $@opened([[OPENED_ID]], any P) Self.A
+// CHECK: [[DEST:%[0-9]+]] = init_existential_addr [[LET]] : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[DEST]], [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out τ_0_0.A
 func testCovariantAssocMethod1(p: any P) {
   let x = p.covariantAssocMethod1()
@@ -330,7 +330,7 @@ func testCovariantAssocMethod1(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocMethod2 : <Self where Self : P> (Self) -> () -> Self.A?
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>(%{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out Optional<τ_0_0.A>
-// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $@opened([[OPENED_ID]], any P) Self.A
+// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
 func testCovariantAssocMethod2(p: any P) {
   let x = p.covariantAssocMethod2()
 }
@@ -338,7 +338,7 @@ func testCovariantAssocMethod2(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocMethod3 : <Self where Self : P> (Self) -> () -> Self.A.Type
 // CHECK: [[META:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @thick τ_0_0.A.Type
-// CHECK: [[EXIST_META:%[0-9]+]] = init_existential_metatype [[META]] : $@thick (@opened([[OPENED_ID]], any P) Self.A).Type, $@thick any Any.Type
+// CHECK: [[EXIST_META:%[0-9]+]] = init_existential_metatype [[META]] : $@thick ((@opened([[OPENED_ID]], any P) Self).A).Type, $@thick any Any.Type
 // CHECK: [[MV:%.*]] = move_value [var_decl] [[EXIST_META]] : $@thick any Any.Type
 // CHECK: debug_value [[MV]] : $@thick any Any.Type, let, name "x"
 func testCovariantAssocMethod3(p: any P) {
@@ -349,8 +349,8 @@ func testCovariantAssocMethod3(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocMethod4 : <Self where Self : P> (Self) -> () -> (Self.A, Self.A)
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>(%{{[0-9]+}}, %{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> (@out τ_0_0.A, @out τ_0_0.A)
-// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $@opened([[OPENED_ID]], any P) Self.A
-// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $@opened([[OPENED_ID]], any P) Self.A
+// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
+// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
 func testCovariantAssocMethod4(p: any P) {
   let x = p.covariantAssocMethod4()
 }
@@ -359,7 +359,7 @@ func testCovariantAssocMethod4(p: any P) {
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocMethod5 : <Self where Self : P> (Self) -> () -> Array<Self.A>
 // CHECK: [[ARRAY:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned Array<τ_0_0.A>
 // CHECK: [[ARRAY_UPCAST_FN:%[0-9]+]] = function_ref @$ss15_arrayForceCastySayq_GSayxGr0_lF : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
-// CHECK: [[RESULT:%[0-9]+]] = apply [[ARRAY_UPCAST_FN]]<@opened([[OPENED_ID]], any P) Self.A, Any>([[ARRAY]]) : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
+// CHECK: [[RESULT:%[0-9]+]] = apply [[ARRAY_UPCAST_FN]]<(@opened([[OPENED_ID]], any P) Self).A, Any>([[ARRAY]]) : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
 // CHECK: debug_value %{{[0-9]+}} : $Array<Any>, let, name "x"
 func testCovariantAssocMethod5(p: any P) {
   let x = p.covariantAssocMethod5()
@@ -369,7 +369,7 @@ func testCovariantAssocMethod5(p: any P) {
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocMethod6 : <Self where Self : P> (Self) -> () -> [String : Self.A]
 // CHECK: [[DICT:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned Dictionary<String, τ_0_0.A>
 // CHECK: [[DICT_UPCAST_FN:%[0-9]+]] = function_ref @$ss17_dictionaryUpCastySDyq0_q1_GSDyxq_GSHRzSHR0_r2_lF : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
-// CHECK: [[RESULT:%[0-9]+]] = apply [[DICT_UPCAST_FN]]<String, @opened([[OPENED_ID]], any P) Self.A, String, Any>([[DICT]]) : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
+// CHECK: [[RESULT:%[0-9]+]] = apply [[DICT_UPCAST_FN]]<String, (@opened([[OPENED_ID]], any P) Self).A, String, Any>([[DICT]]) : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
 // CHECK: debug_value %{{[0-9]+}} : $Dictionary<String, Any>, let, name "x"
 func testCovariantAssocMethod6(p: any P) {
   let x = p.covariantAssocMethod6()
@@ -379,7 +379,7 @@ func testCovariantAssocMethod6(p: any P) {
 // CHECK: function_ref thunk for @callee_guaranteed (@in_guaranteed Any) -> ()
 // CHECK-NEXT: function_ref @$sypIgn_1A42existential_member_accesses_self_assoctype1PPQzIegn_AbCRzlTR : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0.A, @guaranteed @noescape @callee_guaranteed (@in_guaranteed Any) -> ()) -> ()
 // CHECK: [[STEP1:%[0-9]+]] = partial_apply [callee_guaranteed] [[THUNK]]<@opened([[OPENED_ID]], any P) Self>
-// CHECK: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] : $@callee_guaranteed (@in_guaranteed @opened([[OPENED_ID]], any P) Self.A) -> () to $@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <@opened([[OPENED_ID]], any P) Self.A>
+// CHECK: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] : $@callee_guaranteed (@in_guaranteed (@opened([[OPENED_ID]], any P) Self).A) -> () to $@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <(@opened([[OPENED_ID]], any P) Self).A>
 // CHECK: [[STEP3:%[0-9]+]] = convert_escape_to_noescape [not_guaranteed] [[STEP2]]
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocMethod7 : <Self where Self : P> (Self) -> ((Self.A) -> ()) -> ()
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[STEP3]], [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0.A>, @in_guaranteed τ_0_0) -> ()
@@ -390,7 +390,7 @@ func testCovariantAssocMethod7(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*[[OPENED_TY:@opened\("[0-9A-F-]+", any P\) Self]]
 // CHECK: [[THUNK:%[0-9]+]] = function_ref @[[ASSOCTYPE_ARRAY_THUNK_NAME:\$[0-9a-zA-Z_]+]] : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@guaranteed Array<τ_0_0.A>, @guaranteed @noescape @callee_guaranteed (@guaranteed Array<Any>) -> ()) -> ()
 // CHECK: [[STEP1:%[0-9]+]] = partial_apply [callee_guaranteed] [[THUNK]]<[[OPENED_TY]]>
-// CHECK: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] : $@callee_guaranteed (@guaranteed Array<[[OPENED_TY]].A>) -> () to $@callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <[[OPENED_TY]].A>
+// CHECK: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] : $@callee_guaranteed (@guaranteed Array<([[OPENED_TY]]).A>) -> () to $@callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <([[OPENED_TY]]).A>
 // CHECK: [[STEP3:%[0-9]+]] = convert_escape_to_noescape [not_guaranteed] [[STEP2]]
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $[[OPENED_TY]], #P.covariantAssocMethod8 : <Self where Self : P> (Self) -> ((Self.A...) -> ()) -> ()
 // CHECK: apply [[WITNESS]]<[[OPENED_TY]]>([[STEP3]], [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <τ_0_0.A>, @in_guaranteed τ_0_0) -> ()
@@ -407,7 +407,7 @@ func testCovariantAssocMethod8(p: any P) {
 // CHECK: [[LET:%[0-9]+]] = alloc_stack [lexical] [var_decl] $Any, let, name "x"
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocProperty1!getter : <Self where Self : P> (Self) -> () -> Self.A
-// CHECK: [[DEST:%[0-9]+]] = init_existential_addr [[LET]] : $*Any, $@opened([[OPENED_ID]], any P) Self.A
+// CHECK: [[DEST:%[0-9]+]] = init_existential_addr [[LET]] : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[DEST]], [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out τ_0_0.A
 func testCovariantAssocProperty1(p: any P) {
   let x = p.covariantAssocProperty1
@@ -417,7 +417,7 @@ func testCovariantAssocProperty1(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocProperty2!getter : <Self where Self : P> (Self) -> () -> Self.A?
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>(%{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out Optional<τ_0_0.A>
-// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $@opened([[OPENED_ID]], any P) Self.A
+// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
 func testCovariantAssocProperty2(p: any P) {
   let x = p.covariantAssocProperty2
 }
@@ -425,7 +425,7 @@ func testCovariantAssocProperty2(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocProperty3!getter : <Self where Self : P> (Self) -> () -> Self.A.Type
 // CHECK: [[META:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @thick τ_0_0.A.Type
-// CHECK: [[EXIST_META:%[0-9]+]] = init_existential_metatype [[META]] : $@thick (@opened([[OPENED_ID]], any P) Self.A).Type, $@thick any Any.Type
+// CHECK: [[EXIST_META:%[0-9]+]] = init_existential_metatype [[META]] : $@thick ((@opened([[OPENED_ID]], any P) Self).A).Type, $@thick any Any.Type
 // CHECK: [[MV:%.*]] = move_value [var_decl] [[EXIST_META]] : $@thick any Any.Type
 // CHECK: debug_value [[MV]] : $@thick any Any.Type, let, name "x"
 func testCovariantAssocProperty3(p: any P) {
@@ -436,8 +436,8 @@ func testCovariantAssocProperty3(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocProperty4!getter : <Self where Self : P> (Self) -> () -> (Self.A, Self.A)
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>(%{{[0-9]+}}, %{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> (@out τ_0_0.A, @out τ_0_0.A)
-// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $@opened([[OPENED_ID]], any P) Self.A
-// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $@opened([[OPENED_ID]], any P) Self.A
+// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
+// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
 func testCovariantAssocProperty4(p: any P) {
   let x = p.covariantAssocProperty4
 }
@@ -446,7 +446,7 @@ func testCovariantAssocProperty4(p: any P) {
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocProperty5!getter : <Self where Self : P> (Self) -> () -> Array<Self.A>
 // CHECK: [[ARRAY:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned Array<τ_0_0.A>
 // CHECK: [[ARRAY_UPCAST_FN:%[0-9]+]] = function_ref @$ss15_arrayForceCastySayq_GSayxGr0_lF : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
-// CHECK: [[RESULT:%[0-9]+]] = apply [[ARRAY_UPCAST_FN]]<@opened([[OPENED_ID]], any P) Self.A, Any>([[ARRAY]]) : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
+// CHECK: [[RESULT:%[0-9]+]] = apply [[ARRAY_UPCAST_FN]]<(@opened([[OPENED_ID]], any P) Self).A, Any>([[ARRAY]]) : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
 // CHECK: debug_value %{{[0-9]+}} : $Array<Any>, let, name "x"
 func testCovariantAssocProperty5(p: any P) {
   let x = p.covariantAssocProperty5
@@ -456,7 +456,7 @@ func testCovariantAssocProperty5(p: any P) {
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.covariantAssocProperty6!getter : <Self where Self : P> (Self) -> () -> [String : Self.A]
 // CHECK: [[DICT:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned Dictionary<String, τ_0_0.A>
 // CHECK: [[DICT_UPCAST_FN:%[0-9]+]] = function_ref @$ss17_dictionaryUpCastySDyq0_q1_GSDyxq_GSHRzSHR0_r2_lF : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
-// CHECK: [[RESULT:%[0-9]+]] = apply [[DICT_UPCAST_FN]]<String, @opened([[OPENED_ID]], any P) Self.A, String, Any>([[DICT]]) : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
+// CHECK: [[RESULT:%[0-9]+]] = apply [[DICT_UPCAST_FN]]<String, (@opened([[OPENED_ID]], any P) Self).A, String, Any>([[DICT]]) : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
 // CHECK: debug_value %{{[0-9]+}} : $Dictionary<String, Any>, let, name "x"
 func testCovariantAssocProperty6(p: any P) {
   let x = p.covariantAssocProperty6
@@ -465,7 +465,7 @@ func testCovariantAssocProperty6(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self,  #P.covariantAssocProperty7!getter : <Self where Self : P> (Self) -> () -> ((Self.A) -> ()) -> ()
 // CHECK: [[RESULT_FN:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned @callee_guaranteed @substituted <τ_0_0> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0>) -> () for <τ_0_0.A>
-// CHECK: [[STEP1:%[0-9]+]] = convert_function [[RESULT_FN]] : $@callee_guaranteed @substituted <τ_0_0> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0>) -> () for <@opened([[OPENED_ID]], any P) Self.A> to $@callee_guaranteed (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <@opened([[OPENED_ID]], any P) Self.A>) -> ()
+// CHECK: [[STEP1:%[0-9]+]] = convert_function [[RESULT_FN]] : $@callee_guaranteed @substituted <τ_0_0> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0>) -> () for <(@opened([[OPENED_ID]], any P) Self).A> to $@callee_guaranteed (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <(@opened([[OPENED_ID]], any P) Self).A>) -> ()
 // CHECK: [[THUNK:%[0-9]+]] = function_ref @$sxRi_zRi0_zly1A42existential_member_accesses_self_assoctype1PPQzIsgn_Iegg_ypIgn_Iegg_AbCRzlTR : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@guaranteed @noescape @callee_guaranteed (@in_guaranteed Any) -> (), @guaranteed @callee_guaranteed (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0.A>) -> ()) -> ()
 // CHECK: partial_apply [callee_guaranteed] [[THUNK]]<@opened([[OPENED_ID]], any P) Self>([[STEP1]]) : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@guaranteed @noescape @callee_guaranteed (@in_guaranteed Any) -> (), @guaranteed @callee_guaranteed (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0.A>) -> ()) -> ()
 // CHECK: debug_value %{{[0-9]+}} : $@callee_guaranteed (@guaranteed @noescape @callee_guaranteed (@in_guaranteed Any) -> ()) -> (), let, name "x"
@@ -476,7 +476,7 @@ func testCovariantAssocProperty7(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*[[OPENED_TY:@opened\("[0-9A-F-]+", any P\) Self]]
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $[[OPENED_TY]],  #P.covariantAssocProperty8!getter : <Self where Self : P> (Self) -> () -> ((Self.A...) -> ()) -> ()
 // CHECK: [[RESULT_FN:%[0-9]+]] = apply [[WITNESS]]<[[OPENED_TY]]>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned @callee_guaranteed @substituted <τ_0_0> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <τ_0_0>) -> () for <τ_0_0.A>
-// CHECK: [[STEP1:%[0-9]+]] = convert_function [[RESULT_FN]] : $@callee_guaranteed @substituted <τ_0_0> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <τ_0_0>) -> () for <[[OPENED_TY]].A> to $@callee_guaranteed (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <[[OPENED_TY]].A>) -> ()
+// CHECK: [[STEP1:%[0-9]+]] = convert_function [[RESULT_FN]] : $@callee_guaranteed @substituted <τ_0_0> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <τ_0_0>) -> () for <([[OPENED_TY]]).A> to $@callee_guaranteed (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <([[OPENED_TY]]).A>) -> ()
 // CHECK: [[THUNK:%[0-9]+]] = function_ref @[[THUNK_NAME:\$[0-9a-zA-Z_]+]] : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@guaranteed @noescape @callee_guaranteed (@guaranteed Array<Any>) -> (), @guaranteed @callee_guaranteed (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <τ_0_0.A>) -> ()) -> ()
 // CHECK: partial_apply [callee_guaranteed] [[THUNK]]<[[OPENED_TY]]>([[STEP1]])
 // CHECK: debug_value %{{[0-9]+}} : $@callee_guaranteed (@guaranteed @noescape @callee_guaranteed (@guaranteed Array<Any>) -> ()) -> (), let, name "x"
@@ -493,7 +493,7 @@ func testCovariantAssocProperty8(p: any P) {
 // CHECK: [[LET:%[0-9]+]] = alloc_stack [lexical] [var_decl] $Any, let, name "x"
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.subscript!getter : <Self where Self : P> (Self) -> (()) -> Self.A
-// CHECK: [[DEST:%[0-9]+]] = init_existential_addr [[LET]] : $*Any, $@opened([[OPENED_ID]], any P) Self.A
+// CHECK: [[DEST:%[0-9]+]] = init_existential_addr [[LET]] : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[DEST]], [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out τ_0_0.A
 func testCovariantAssocSubscript1(p: any P) {
   let x = p[covariantAssocSubscript1: ()]
@@ -503,7 +503,7 @@ func testCovariantAssocSubscript1(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.subscript!getter : <Self where Self : P> (Self) -> (()) -> Self.A?
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>(%{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out Optional<τ_0_0.A>
-// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $@opened([[OPENED_ID]], any P) Self.A
+// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
 func testCovariantAssocSubscript2(p: any P) {
   let x = p[covariantAssocSubscript2: ()]
 }
@@ -511,7 +511,7 @@ func testCovariantAssocSubscript2(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.subscript!getter : <Self where Self : P> (Self) -> (()) -> Self.A.Type
 // CHECK: [[META:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @thick τ_0_0.A.Type
-// CHECK: [[EXIST_META:%[0-9]+]] = init_existential_metatype [[META]] : $@thick (@opened([[OPENED_ID]], any P) Self.A).Type, $@thick any Any.Type
+// CHECK: [[EXIST_META:%[0-9]+]] = init_existential_metatype [[META]] : $@thick ((@opened([[OPENED_ID]], any P) Self).A).Type, $@thick any Any.Type
 // CHECK: [[MV:%.*]] = move_value [var_decl] [[EXIST_META]] : $@thick any Any.Type
 // CHECK: debug_value [[MV]] : $@thick any Any.Type, let, name "x"
 func testCovariantAssocSubscript3(p: any P) {
@@ -522,8 +522,8 @@ func testCovariantAssocSubscript3(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.subscript!getter : <Self where Self : P> (Self) -> (()) -> (Self.A, Self.A)
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>(%{{[0-9]+}}, %{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> (@out τ_0_0.A, @out τ_0_0.A)
-// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $@opened([[OPENED_ID]], any P) Self.A
-// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $@opened([[OPENED_ID]], any P) Self.A
+// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
+// CHECK: init_existential_addr %{{[0-9]+}} : $*Any, $(@opened([[OPENED_ID]], any P) Self).A
 func testCovariantAssocSubscript4(p: any P) {
   let x = p[covariantAssocSubscript4: ()]
 }
@@ -532,7 +532,7 @@ func testCovariantAssocSubscript4(p: any P) {
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.subscript!getter : <Self where Self : P> (Self) -> (()) -> Array<Self.A>
 // CHECK: [[ARRAY:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned Array<τ_0_0.A>
 // CHECK: [[ARRAY_UPCAST_FN:%[0-9]+]] = function_ref @$ss15_arrayForceCastySayq_GSayxGr0_lF : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
-// CHECK: [[RESULT:%[0-9]+]] = apply [[ARRAY_UPCAST_FN]]<@opened([[OPENED_ID]], any P) Self.A, Any>([[ARRAY]]) : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
+// CHECK: [[RESULT:%[0-9]+]] = apply [[ARRAY_UPCAST_FN]]<(@opened([[OPENED_ID]], any P) Self).A, Any>([[ARRAY]]) : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
 // CHECK: debug_value %{{[0-9]+}} : $Array<Any>, let, name "x"
 func testCovariantAssocSubscript5(p: any P) {
   let x = p[covariantAssocSubscript5: ()]
@@ -542,7 +542,7 @@ func testCovariantAssocSubscript5(p: any P) {
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.subscript!getter : <Self where Self : P> (Self) -> (()) -> [String : Self.A]
 // CHECK: [[DICT:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned Dictionary<String, τ_0_0.A>
 // CHECK: [[DICT_UPCAST_FN:%[0-9]+]] = function_ref @$ss17_dictionaryUpCastySDyq0_q1_GSDyxq_GSHRzSHR0_r2_lF : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
-// CHECK: [[RESULT:%[0-9]+]] = apply [[DICT_UPCAST_FN]]<String, @opened([[OPENED_ID]], any P) Self.A, String, Any>([[DICT]]) : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
+// CHECK: [[RESULT:%[0-9]+]] = apply [[DICT_UPCAST_FN]]<String, (@opened([[OPENED_ID]], any P) Self).A, String, Any>([[DICT]]) : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
 // CHECK: debug_value %{{[0-9]+}} : $Dictionary<String, Any>, let, name "x"
 func testCovariantAssocSubscript6(p: any P) {
   let x = p[covariantAssocSubscript6: ()]
@@ -551,7 +551,7 @@ func testCovariantAssocSubscript6(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P) Self
 // CHECK: [[THUNK:%[0-9]+]] = function_ref @$sypIgn_1A42existential_member_accesses_self_assoctype1PPQzIegn_AbCRzlTR : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0.A, @guaranteed @noescape @callee_guaranteed (@in_guaranteed Any) -> ()) -> ()
 // CHECK: [[STEP1:%[0-9]+]] = partial_apply [callee_guaranteed] [[THUNK]]<@opened([[OPENED_ID]], any P) Self>
-// CHECK: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] : $@callee_guaranteed (@in_guaranteed @opened([[OPENED_ID]], any P) Self.A) -> () to $@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <@opened([[OPENED_ID]], any P) Self.A>
+// CHECK: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] : $@callee_guaranteed (@in_guaranteed (@opened([[OPENED_ID]], any P) Self).A) -> () to $@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <(@opened([[OPENED_ID]], any P) Self).A>
 // CHECK: [[STEP3:%[0-9]+]] = convert_escape_to_noescape [not_guaranteed] [[STEP2]]
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P) Self, #P.subscript!getter : <Self where Self : P> (Self) -> ((Self.A) -> ()) -> ()
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P) Self>([[STEP3]], [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0.A>, @in_guaranteed τ_0_0) -> ()
@@ -562,7 +562,7 @@ func testCovariantAssocSubscript7(p: any P) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P to $*[[OPENED_TY:@opened\("[0-9A-F-]+", any P\) Self]]
 // CHECK: [[THUNK:%[0-9]+]] = function_ref @[[ASSOCTYPE_ARRAY_THUNK_NAME]] : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@guaranteed Array<τ_0_0.A>, @guaranteed @noescape @callee_guaranteed (@guaranteed Array<Any>) -> ()) -> ()
 // CHECK: [[STEP1:%[0-9]+]] = partial_apply [callee_guaranteed] [[THUNK]]<[[OPENED_TY]]>
-// CHECK: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] : $@callee_guaranteed (@guaranteed Array<[[OPENED_TY]].A>) -> () to $@callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <[[OPENED_TY]].A>
+// CHECK: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] : $@callee_guaranteed (@guaranteed Array<([[OPENED_TY]]).A>) -> () to $@callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <([[OPENED_TY]]).A>
 // CHECK: [[STEP3:%[0-9]+]] = convert_escape_to_noescape [not_guaranteed] [[STEP2]]
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $[[OPENED_TY]], #P.subscript!getter : <Self where Self : P> (Self) -> ((Self.A...) -> ()) -> ()
 // CHECK: apply [[WITNESS]]<[[OPENED_TY]]>([[STEP3]], [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@guaranteed Array<τ_0_0>) -> () for <τ_0_0.A>, @in_guaranteed τ_0_0) -> ()
@@ -581,7 +581,7 @@ protocol P2: P where A: Class & P {}
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P2 to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P2) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P2) Self, #P.covariantAssocMethod1 : <Self where Self : P> (Self) -> () -> Self.A
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P2) Self>(%{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out τ_0_0.A
-// CHECK: init_existential_ref %{{[0-9]+}} : $@opened([[OPENED_ID]], any P2) Self.A : $@opened([[OPENED_ID]], any P2) Self.A, $any Class & P
+// CHECK: init_existential_ref %{{[0-9]+}} : $(@opened([[OPENED_ID]], any P2) Self).A : $(@opened([[OPENED_ID]], any P2) Self).A, $any Class & P
 // CHECK: debug_value %{{[0-9]+}} : $any Class & P, let, name "x"
 func testCovariantAssocMethod1Constrained(p2: any P2) {
   let x = p2.covariantAssocMethod1()
@@ -590,7 +590,7 @@ func testCovariantAssocMethod1Constrained(p2: any P2) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P2 to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P2) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P2) Self, #P.covariantAssocMethod2 : <Self where Self : P> (Self) -> () -> Self.A?
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P2) Self>(%{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out Optional<τ_0_0.A>
-// CHECK: init_existential_ref %{{[0-9]+}} : $@opened([[OPENED_ID]], any P2) Self.A : $@opened([[OPENED_ID]], any P2) Self.A, $any Class & P
+// CHECK: init_existential_ref %{{[0-9]+}} : $(@opened([[OPENED_ID]], any P2) Self).A : $(@opened([[OPENED_ID]], any P2) Self).A, $any Class & P
 // CHECK: debug_value %{{[0-9]+}} : $Optional<any Class & P>, let, name "x"
 func testCovariantAssocMethod2Constrained(p2: any P2) {
   let x = p2.covariantAssocMethod2()
@@ -599,7 +599,7 @@ func testCovariantAssocMethod2Constrained(p2: any P2) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P2 to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P2) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P2) Self, #P.covariantAssocMethod3 : <Self where Self : P> (Self) -> () -> Self.A.Type
 // CHECK: [[META:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P2) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @thick τ_0_0.A.Type
-// CHECK: [[EXIST_META:%[0-9]+]] = init_existential_metatype [[META]] : $@thick (@opened([[OPENED_ID]], any P2) Self.A).Type, $@thick any (Class & P).Type
+// CHECK: [[EXIST_META:%[0-9]+]] = init_existential_metatype [[META]] : $@thick ((@opened([[OPENED_ID]], any P2) Self).A).Type, $@thick any (Class & P).Type
 // CHECK: [[MV:%.*]] = move_value [var_decl] [[EXIST_META]]
 // CHECK: debug_value [[MV]] : $@thick any (Class & P).Type, let, name "x"
 func testCovariantAssocMethod3Constrained(p2: any P2) {
@@ -609,8 +609,8 @@ func testCovariantAssocMethod3Constrained(p2: any P2) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P2 to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P2) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P2) Self, #P.covariantAssocMethod4 : <Self where Self : P> (Self) -> () -> (Self.A, Self.A)
 // CHECK: apply [[WITNESS]]<@opened([[OPENED_ID]], any P2) Self>(%{{[0-9]+}}, %{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> (@out τ_0_0.A, @out τ_0_0.A)
-// CHECK: init_existential_ref %{{[0-9]+}} : $@opened([[OPENED_ID]], any P2) Self.A : $@opened([[OPENED_ID]], any P2) Self.A, $any Class & P
-// CHECK: init_existential_ref %{{[0-9]+}} : $@opened([[OPENED_ID]], any P2) Self.A : $@opened([[OPENED_ID]], any P2) Self.A, $any Class & P
+// CHECK: init_existential_ref %{{[0-9]+}} : $(@opened([[OPENED_ID]], any P2) Self).A : $(@opened([[OPENED_ID]], any P2) Self).A, $any Class & P
+// CHECK: init_existential_ref %{{[0-9]+}} : $(@opened([[OPENED_ID]], any P2) Self).A : $(@opened([[OPENED_ID]], any P2) Self).A, $any Class & P
 // CHECK: debug_value %{{[0-9]+}} : $(any Class & P, any Class & P), let, name "x"
 func testCovariantAssocMethod4Constrained(p2: any P2) {
   let x = p2.covariantAssocMethod4()
@@ -620,7 +620,7 @@ func testCovariantAssocMethod4Constrained(p2: any P2) {
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P2) Self, #P.covariantAssocMethod5 : <Self where Self : P> (Self) -> () -> Array<Self.A>
 // CHECK: [[ARRAY:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P2) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned Array<τ_0_0.A>
 // CHECK: [[ARRAY_UPCAST_FN:%[0-9]+]] = function_ref @$ss15_arrayForceCastySayq_GSayxGr0_lF : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
-// CHECK: [[RESULT:%[0-9]+]] = apply [[ARRAY_UPCAST_FN]]<@opened([[OPENED_ID]], any P2) Self.A, any Class & P>([[ARRAY]]) : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
+// CHECK: [[RESULT:%[0-9]+]] = apply [[ARRAY_UPCAST_FN]]<(@opened([[OPENED_ID]], any P2) Self).A, any Class & P>([[ARRAY]]) : $@convention(thin) <τ_0_0, τ_0_1> (@guaranteed Array<τ_0_0>) -> @owned Array<τ_0_1>
 // CHECK: debug_value %{{[0-9]+}} : $Array<any Class & P>, let, name "x"
 func testCovariantAssocMethod5Constrained(p2: any P2) {
   let x = p2.covariantAssocMethod5()
@@ -630,7 +630,7 @@ func testCovariantAssocMethod5Constrained(p2: any P2) {
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P2) Self, #P.covariantAssocMethod6 : <Self where Self : P> (Self) -> () -> [String : Self.A]
 // CHECK: [[DICT:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P2) Self>([[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @owned Dictionary<String, τ_0_0.A>
 // CHECK: [[DICT_UPCAST_FN:%[0-9]+]] = function_ref @$ss17_dictionaryUpCastySDyq0_q1_GSDyxq_GSHRzSHR0_r2_lF : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
-// CHECK: [[RESULT:%[0-9]+]] = apply [[DICT_UPCAST_FN]]<String, @opened([[OPENED_ID]], any P2) Self.A, String, any Class & P>([[DICT]]) : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
+// CHECK: [[RESULT:%[0-9]+]] = apply [[DICT_UPCAST_FN]]<String, (@opened([[OPENED_ID]], any P2) Self).A, String, any Class & P>([[DICT]]) : $@convention(thin) <τ_0_0, τ_0_1, τ_0_2, τ_0_3 where τ_0_0 : Hashable, τ_0_2 : Hashable> (@guaranteed Dictionary<τ_0_0, τ_0_1>) -> @owned Dictionary<τ_0_2, τ_0_3>
 // CHECK: debug_value %{{[0-9]+}} : $Dictionary<String, any Class & P>, let, name "x"
 func testCovariantAssocMethod6Constrained(p2: any P2) {
   let x = p2.covariantAssocMethod6()
@@ -640,7 +640,7 @@ func testCovariantAssocMethod6Constrained(p2: any P2) {
 // CHECK: function_ref thunk for @callee_guaranteed (@guaranteed Class & P) -> ()
 // CHECK-NEXT: [[THUNK1:%[0-9]+]] = function_ref @$s42existential_member_accesses_self_assoctype1P_AA5ClassCXcIgg_1AAaBPQzIegn_AA2P2RzlTR : $@convention(thin) <τ_0_0 where τ_0_0 : P2> (@in_guaranteed τ_0_0.A, @guaranteed @noescape @callee_guaranteed (@guaranteed any Class & P) -> ()) -> ()
 // CHECK-NEXT: [[STEP1:%[0-9]+]] = partial_apply [callee_guaranteed] [[THUNK1]]<@opened([[OPENED_ID]], any P2) Self>
-// CHECK-NEXT: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] :  $@callee_guaranteed (@in_guaranteed @opened([[OPENED_ID]], any P2) Self.A) -> () to $@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <@opened([[OPENED_ID]], any P2) Self.A>
+// CHECK-NEXT: [[STEP2:%[0-9]+]] = convert_function [[STEP1]] :  $@callee_guaranteed (@in_guaranteed (@opened([[OPENED_ID]], any P2) Self).A) -> () to $@callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <(@opened([[OPENED_ID]], any P2) Self).A>
 // CHECK-NEXT: [[STEP3:%[0-9]+]] = convert_escape_to_noescape [not_guaranteed] [[STEP2]]
 // CHECK-NEXT: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P2) Self, #P.covariantAssocMethod7 : <Self where Self : P> (Self) -> ((Self.A) -> ()) -> ()
 // CHECK-NEXT: apply [[WITNESS]]<@opened([[OPENED_ID]], any P2) Self>([[STEP3]], [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> (@in_guaranteed τ_0_0) -> () for <τ_0_0.A>, @in_guaranteed τ_0_0) -> ()
@@ -708,7 +708,7 @@ protocol P5<A>{
 // CHECK-LABEL: sil hidden [ossa] @$s42existential_member_accesses_self_assoctype30testCovariantAssocGenericClass2p5AA0iJ0CySiGAA2P5_pSi1AAaGPRts_XP_tF
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P5<Int> to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P5<Int>) Self
 // CHECK: [[APPLY:%[0-9]+]] = apply [[WITNESS]]<@opened([[OPENED_ID]], any P5<Int>) Self>([[OPENED]]) : $@convention(witness_method: P5) <τ_0_0 where τ_0_0 : P5> (@in_guaranteed τ_0_0) -> @owned τ_0_0.B
-// CHECK: [[UPCAST:%[0-9]+]] = upcast [[APPLY]] : $@opened([[OPENED_ID]], any P5<Int>) Self.B to $GenericClass<Int>
+// CHECK: [[UPCAST:%[0-9]+]] = upcast [[APPLY]] : $(@opened([[OPENED_ID]], any P5<Int>) Self).B to $GenericClass<Int>
 // CHECK: return %{{[0-9]+}} : $GenericClass<Int>
 // CHECK: } // end sil function '$s42existential_member_accesses_self_assoctype30testCovariantAssocGenericClass2p5AA0iJ0CySiGAA2P5_pSi1AAaGPRts_XP_tF'
 func testCovariantAssocGenericClass(p5: any P5<Int>) -> GenericClass<Int> {
@@ -719,7 +719,7 @@ func testCovariantAssocGenericClass(p5: any P5<Int>) -> GenericClass<Int> {
 // CHECK-LABEL: sil hidden [ossa] @$s42existential_member_accesses_self_assoctype33testCovariantAssocGenericSubClass2p5AA0ijK0CySbGAA2P5_pSb1AAaGPRts_XP_tF
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P5<Bool> to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P5<Bool>) Self
 // CHECK: apply %3<@opened([[OPENED_ID]], any P5<Bool>) Self>([[OPENED]]) : $@convention(witness_method: P5) <τ_0_0 where τ_0_0 : P5> (@in_guaranteed τ_0_0) -> @owned τ_0_0.C
-// CHECK: [[UPCAST:%[0-9]+]] = upcast [[APPLY:%[0-9]+]] : $@opened([[OPENED_ID]], any P5<Bool>) Self.C to $GenericSubClass<Bool>
+// CHECK: [[UPCAST:%[0-9]+]] = upcast [[APPLY:%[0-9]+]] : $(@opened([[OPENED_ID]], any P5<Bool>) Self).C to $GenericSubClass<Bool>
 // CHECK: return %{{[0-9]+}} : $GenericSubClass<Bool>
 // CHECK: } // end sil function '$s42existential_member_accesses_self_assoctype33testCovariantAssocGenericSubClass2p5AA0ijK0CySbGAA2P5_pSb1AAaGPRts_XP_tF'
 func testCovariantAssocGenericSubClass(p5: any P5<Bool>) -> GenericSubClass<Bool> {
@@ -740,8 +740,8 @@ protocol P4: P where A == (B, B) {
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access %0 : $*any P4 to $*@opened([[OPENED_ID:"[0-9A-F-]+"]], any P4) Self
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $@opened([[OPENED_ID]], any P4) Self, #P.covariantAssocMethod1 : <Self where Self : P> (Self) -> () -> Self.A
 // CHECK: apply %4<@opened([[OPENED_ID]], any P4) Self>(%{{[0-9]+}}, [[OPENED]]) : $@convention(witness_method: P) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out τ_0_0.A
-// CHECK: init_existential_addr %{{[0-9]+}} : $*any P4, $@opened([[OPENED_ID]], any P4) Self.B
-// CHECK: init_existential_addr %{{[0-9]+}} : $*any P4, $@opened([[OPENED_ID]], any P4) Self.B
+// CHECK: init_existential_addr %{{[0-9]+}} : $*any P4, $(@opened([[OPENED_ID]], any P4) Self).B
+// CHECK: init_existential_addr %{{[0-9]+}} : $*any P4, $(@opened([[OPENED_ID]], any P4) Self).B
 func testCovariantAssocMethod1PartiallyConcrete(p4: any P4) {
   let x = p4.covariantAssocMethod1()
 }
diff --git a/test/SILGen/foreach.swift b/test/SILGen/foreach.swift
index 1a26e6c4db80c..8a16840653184 100644
--- a/test/SILGen/foreach.swift
+++ b/test/SILGen/foreach.swift
@@ -111,14 +111,14 @@ func trivialStructBreak(_ xx: [Int]) {
 // CHECK:   [[BORROWED_ARRAY_STACK:%.*]] = alloc_stack $Array<Int>
 // CHECK:   store [[ARRAY_COPY:%.*]] to [init] [[BORROWED_ARRAY_STACK]]
 // CHECK:   [[MAKE_ITERATOR_FUNC:%.*]] = function_ref @$sSlss16IndexingIteratorVyxG0B0RtzrlE04makeB0ACyF : $@convention(method) <τ_0_0 where τ_0_0 : Collection, τ_0_0.Iterator == IndexingIterator<τ_0_0>> (@in τ_0_0) -> @out IndexingIterator<τ_0_0>
-// CHECK:   apply [[MAKE_ITERATOR_FUNC]]<[Int]>([[PROJECT_ITERATOR_BOX]], [[BORROWED_ARRAY_STACK]])
+// CHECK:   apply [[MAKE_ITERATOR_FUNC]]<Array<Int>>([[PROJECT_ITERATOR_BOX]], [[BORROWED_ARRAY_STACK]])
 // CHECK:   br [[LOOP_DEST:bb[0-9]+]]
 //
 // CHECK: [[LOOP_DEST]]:
 // CHECK:   [[GET_ELT_STACK:%.*]] = alloc_stack $Optional<Int>
 // CHECK:   [[WRITE:%.*]] = begin_access [modify] [unknown] [[PROJECT_ITERATOR_BOX]] : $*IndexingIterator<Array<Int>>
 // CHECK:   [[FUNC_REF:%.*]] = function_ref @$ss16IndexingIteratorV4next7ElementQzSgyF : $@convention(method) <τ_0_0 where τ_0_0 : Collection> (@inout IndexingIterator<τ_0_0>) -> @out Optional<τ_0_0.Element>
-// CHECK:   apply [[FUNC_REF]]<[Int]>([[GET_ELT_STACK]], [[WRITE]])
+// CHECK:   apply [[FUNC_REF]]<Array<Int>>([[GET_ELT_STACK]], [[WRITE]])
 // CHECK:   [[IND_VAR:%.*]] = load [trivial] [[GET_ELT_STACK]]
 // CHECK:   switch_enum [[IND_VAR]] : $Optional<Int>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[NONE_BB:bb[0-9]+]]
 //
@@ -212,14 +212,14 @@ func existentialBreak(_ xx: [P]) {
 // CHECK:   [[BORROWED_ARRAY_STACK:%.*]] = alloc_stack $Array<any P>
 // CHECK:   store [[ARRAY_COPY:%.*]] to [init] [[BORROWED_ARRAY_STACK]]
 // CHECK:   [[MAKE_ITERATOR_FUNC:%.*]] = function_ref @$sSlss16IndexingIteratorVyxG0B0RtzrlE04makeB0ACyF : $@convention(method) <τ_0_0 where τ_0_0 : Collection, τ_0_0.Iterator == IndexingIterator<τ_0_0>> (@in τ_0_0) -> @out IndexingIterator<τ_0_0>
-// CHECK:   apply [[MAKE_ITERATOR_FUNC]]<[any P]>([[PROJECT_ITERATOR_BOX]], [[BORROWED_ARRAY_STACK]])
+// CHECK:   apply [[MAKE_ITERATOR_FUNC]]<Array<any P>>([[PROJECT_ITERATOR_BOX]], [[BORROWED_ARRAY_STACK]])
 // CHECK:   [[ELT_STACK:%.*]] = alloc_stack $Optional<any P>
 // CHECK:   br [[LOOP_DEST:bb[0-9]+]]
 //
 // CHECK: [[LOOP_DEST]]:
 // CHECK:   [[WRITE:%.*]] = begin_access [modify] [unknown] [[PROJECT_ITERATOR_BOX]] : $*IndexingIterator<Array<any P>>
 // CHECK:   [[FUNC_REF:%.*]] = function_ref @$ss16IndexingIteratorV4next7ElementQzSgyF : $@convention(method) <τ_0_0 where τ_0_0 : Collection> (@inout IndexingIterator<τ_0_0>) -> @out Optional<τ_0_0.Element>
-// CHECK:   apply [[FUNC_REF]]<[any P]>([[ELT_STACK]], [[WRITE]])
+// CHECK:   apply [[FUNC_REF]]<Array<any P>>([[ELT_STACK]], [[WRITE]])
 // CHECK:   switch_enum_addr [[ELT_STACK]] : $*Optional<any P>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[NONE_BB:bb[0-9]+]]
 //
 // CHECK: [[SOME_BB]]:
@@ -373,14 +373,14 @@ func genericStructBreak<T>(_ xx: [GenericStruct<T>]) {
 // CHECK:   [[BORROWED_ARRAY_STACK:%.*]] = alloc_stack $Array<GenericStruct<T>>
 // CHECK:   store [[ARRAY_COPY:%.*]] to [init] [[BORROWED_ARRAY_STACK]]
 // CHECK:   [[MAKE_ITERATOR_FUNC:%.*]] = function_ref @$sSlss16IndexingIteratorVyxG0B0RtzrlE04makeB0ACyF : $@convention(method) <τ_0_0 where τ_0_0 : Collection, τ_0_0.Iterator == IndexingIterator<τ_0_0>> (@in τ_0_0) -> @out IndexingIterator<τ_0_0>
-// CHECK:   apply [[MAKE_ITERATOR_FUNC]]<[GenericStruct<T>]>([[PROJECT_ITERATOR_BOX]], [[BORROWED_ARRAY_STACK]])
+// CHECK:   apply [[MAKE_ITERATOR_FUNC]]<Array<GenericStruct<T>>>([[PROJECT_ITERATOR_BOX]], [[BORROWED_ARRAY_STACK]])
 // CHECK:   [[ELT_STACK:%.*]] = alloc_stack $Optional<GenericStruct<T>>
 // CHECK:   br [[LOOP_DEST:bb[0-9]+]]
 //
 // CHECK: [[LOOP_DEST]]:
 // CHECK:   [[WRITE:%.*]] = begin_access [modify] [unknown] [[PROJECT_ITERATOR_BOX]] : $*IndexingIterator<Array<GenericStruct<T>>>
 // CHECK:   [[FUNC_REF:%.*]] = function_ref @$ss16IndexingIteratorV4next7ElementQzSgyF : $@convention(method) <τ_0_0 where τ_0_0 : Collection> (@inout IndexingIterator<τ_0_0>) -> @out Optional<τ_0_0.Element>
-// CHECK:   apply [[FUNC_REF]]<[GenericStruct<T>]>([[ELT_STACK]], [[WRITE]])
+// CHECK:   apply [[FUNC_REF]]<Array<GenericStruct<T>>>([[ELT_STACK]], [[WRITE]])
 // CHECK:   switch_enum_addr [[ELT_STACK]] : $*Optional<GenericStruct<T>>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[NONE_BB:bb[0-9]+]]
 //
 // CHECK: [[SOME_BB]]:
diff --git a/test/SILGen/foreach_async.swift b/test/SILGen/foreach_async.swift
index 918802c243867..ac48e3ad14020 100644
--- a/test/SILGen/foreach_async.swift
+++ b/test/SILGen/foreach_async.swift
@@ -84,7 +84,7 @@ struct AsyncLazySequence<S: Sequence>: AsyncSequence {
 // CHECK:   [[MUTATION:%.*]] = begin_access
 // CHECK:   [[WITNESS_METHOD:%.*]] = function_ref @$sScIsE4next9isolation7ElementQzSgScA_pSgYi_tYa7FailureQzYKF : $@convention(method) @async <τ_0_0 where τ_0_0 : AsyncIteratorProtocol> (@sil_isolated @guaranteed Optional<any Actor>, @inout τ_0_0) -> (@out Optional<τ_0_0.Element>, @error_indirect τ_0_0.Failure)
 // CHECK:   [[ERROR_SLOT:%[0-9]+]] = alloc_stack $Never
-// CHECK:   try_apply [[WITNESS_METHOD]]<AsyncLazySequence<[Int]>.Iterator>([[NEXT_RESULT]], [[ERROR_SLOT]], [[ACTOR]], [[MUTATION]]) : $@convention(method) @async <τ_0_0 where τ_0_0 : AsyncIteratorProtocol> (@sil_isolated @guaranteed Optional<any Actor>, @inout τ_0_0) -> (@out Optional<τ_0_0.Element>, @error_indirect τ_0_0.Failure), normal [[NORMAL_BB:bb[0-2]+]], error [[ERROR_BB:bb[0-9]+]]
+// CHECK:   try_apply [[WITNESS_METHOD]]<AsyncLazySequence<Array<Int>>.Iterator>([[NEXT_RESULT]], [[ERROR_SLOT]], [[ACTOR]], [[MUTATION]]) : $@convention(method) @async <τ_0_0 where τ_0_0 : AsyncIteratorProtocol> (@sil_isolated @guaranteed Optional<any Actor>, @inout τ_0_0) -> (@out Optional<τ_0_0.Element>, @error_indirect τ_0_0.Failure), normal [[NORMAL_BB:bb[0-2]+]], error [[ERROR_BB:bb[0-9]+]]
 // CHECK: [[NORMAL_BB]](
 // CHECK:   end_access [[MUTATION]]
 // CHECK:   switch_enum [[IND_VAR:%.*]] : $Optional<Int>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[NONE_BB:bb[0-9]+]]
@@ -117,7 +117,7 @@ func trivialStruct(_ xx: AsyncLazySequence<[Int]>) async {
 // CHECK:   [[MUTATION:%.*]] = begin_access
 // CHECK:   [[WITNESS_METHOD:%.*]] = function_ref @$sScIsE4next9isolation7ElementQzSgScA_pSgYi_tYa7FailureQzYKF : $@convention(method) @async <τ_0_0 where τ_0_0 : AsyncIteratorProtocol> (@sil_isolated @guaranteed Optional<any Actor>, @inout τ_0_0) -> (@out Optional<τ_0_0.Element>, @error_indirect τ_0_0.Failure)
 // CHECK:   [[ERROR_SLOT:%[0-9]+]] = alloc_stack $Never
-// CHECK:   try_apply [[WITNESS_METHOD]]<AsyncLazySequence<[Int]>.Iterator>([[NEXT_RESULT]], [[ERROR_SLOT]], [[ACTOR]], [[MUTATION]]) : $@convention(method) @async <τ_0_0 where τ_0_0 : AsyncIteratorProtocol> (@sil_isolated @guaranteed Optional<any Actor>, @inout τ_0_0) -> (@out Optional<τ_0_0.Element>, @error_indirect τ_0_0.Failure), normal [[NORMAL_BB:bb[0-2]+]], error [[ERROR_BB:bb[0-9]+]]
+// CHECK:   try_apply [[WITNESS_METHOD]]<AsyncLazySequence<Array<Int>>.Iterator>([[NEXT_RESULT]], [[ERROR_SLOT]], [[ACTOR]], [[MUTATION]]) : $@convention(method) @async <τ_0_0 where τ_0_0 : AsyncIteratorProtocol> (@sil_isolated @guaranteed Optional<any Actor>, @inout τ_0_0) -> (@out Optional<τ_0_0.Element>, @error_indirect τ_0_0.Failure), normal [[NORMAL_BB:bb[0-2]+]], error [[ERROR_BB:bb[0-9]+]]
 // CHECK:  [[NORMAL_BB]](
 // CHECK:   end_access [[MUTATION]]
 // CHECK:   switch_enum [[IND_VAR:%.*]] : $Optional<Int>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[NONE_BB:bb[0-9]+]]
@@ -177,7 +177,7 @@ func trivialStructBreak(_ xx: AsyncLazySequence<[Int]>) async {
 // CHECK:   [[MUTATION:%.*]] = begin_access
 // CHECK:   [[WITNESS_METHOD:%.*]] = function_ref @$sScIsE4next9isolation7ElementQzSgScA_pSgYi_tYa7FailureQzYKF : $@convention(method) @async <τ_0_0 where τ_0_0 : AsyncIteratorProtocol> (@sil_isolated @guaranteed Optional<any Actor>, @inout τ_0_0) -> (@out Optional<τ_0_0.Element>, @error_indirect τ_0_0.Failure)
 // CHECK:   [[ERROR_SLOT:%[0-9]+]] = alloc_stack $Never
-// CHECK:   try_apply [[WITNESS_METHOD]]<AsyncLazySequence<[Int]>.Iterator>([[NEXT_RESULT]], [[ERROR_SLOT]], [[ACTOR]], [[MUTATION]]) : $@convention(method) @async <τ_0_0 where τ_0_0 : AsyncIteratorProtocol> (@sil_isolated @guaranteed Optional<any Actor>, @inout τ_0_0) -> (@out Optional<τ_0_0.Element>, @error_indirect τ_0_0.Failure), normal [[NORMAL_BB:bb[0-2]+]], error [[ERROR_BB:bb[0-9]+]]
+// CHECK:   try_apply [[WITNESS_METHOD]]<AsyncLazySequence<Array<Int>>.Iterator>([[NEXT_RESULT]], [[ERROR_SLOT]], [[ACTOR]], [[MUTATION]]) : $@convention(method) @async <τ_0_0 where τ_0_0 : AsyncIteratorProtocol> (@sil_isolated @guaranteed Optional<any Actor>, @inout τ_0_0) -> (@out Optional<τ_0_0.Element>, @error_indirect τ_0_0.Failure), normal [[NORMAL_BB:bb[0-2]+]], error [[ERROR_BB:bb[0-9]+]]
 // CHECK:  [[NORMAL_BB]](
 // CHECK:   end_access [[MUTATION]]
 // CHECK:   switch_enum [[IND_VAR:%.*]] : $Optional<Int>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[NONE_BB:bb[0-9]+]]
diff --git a/test/SILGen/generic_casts.swift b/test/SILGen/generic_casts.swift
index d11dac0ca237b..a388d903563e0 100644
--- a/test/SILGen/generic_casts.swift
+++ b/test/SILGen/generic_casts.swift
@@ -1,5 +1,5 @@
 
-// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -swift-version 5 -module-name generic_casts -Xllvm -sil-full-demangle %s | %FileCheck %s
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -disable-objc-interop -swift-version 5 -module-name generic_casts -Xllvm -sil-full-demangle %s | %FileCheck %s
 
 protocol ClassBound : class {}
 protocol NotClassBound {}
@@ -59,8 +59,7 @@ func class_archetype_to_class_archetype
 <T:ClassBound, U:ClassBound>(_ t:T) -> U {
   return t as! U
   // Error bridging can change the identity of class-constrained archetypes.
-  // CHECK: unconditional_checked_cast_addr T in {{%.*}} : $*T to U in [[DOWNCAST_ADDR:%.*]] : $*U
-  // CHECK: [[DOWNCAST:%.*]] = load [take] [[DOWNCAST_ADDR]]
+  // CHECK: [[DOWNCAST:%.*]] = unconditional_checked_cast {{%.*}} : $T to U
   // CHECK: return [[DOWNCAST]] : $U
 }
 
@@ -69,7 +68,7 @@ func class_archetype_is_class_archetype
 <T:ClassBound, U:ClassBound>(_ t:T, u:U.Type) -> Bool {
   return t is U
   // Error bridging can change the identity of class-constrained archetypes.
-  // CHECK: checked_cast_addr_br {{.*}} T in {{%.*}} : $*T to U in {{%.*}} : $*U
+  // CHECK: checked_cast_br T in {{%.*}} : $T to U
 }
 
 // CHECK-LABEL: sil hidden [ossa] @$s13generic_casts38opaque_archetype_to_addr_only_concrete{{[_0-9a-zA-Z]*}}F
@@ -158,8 +157,7 @@ func opaque_existential_is_class_archetype
 func class_existential_to_class_archetype
 <T:ClassBound>(_ p:ClassBound) -> T {
   return p as! T
-  // CHECK: unconditional_checked_cast_addr any ClassBound in {{%.*}} : $*any ClassBound to T in [[DOWNCAST_ADDR:%.*]] : $*T
-  // CHECK: [[DOWNCAST:%.*]] = load [take] [[DOWNCAST_ADDR]]
+  // CHECK: [[DOWNCAST:%.*]] = unconditional_checked_cast {{%.*}} : $any ClassBound to T
   // CHECK: return [[DOWNCAST]] : $T
 }
 
@@ -167,7 +165,7 @@ func class_existential_to_class_archetype
 func class_existential_is_class_archetype
 <T:ClassBound>(_ p:ClassBound, _: T) -> Bool {
   return p is T
-  // CHECK: checked_cast_addr_br {{.*}} any ClassBound in {{%.*}} : $*any ClassBound to T in {{%.*}} : $*T
+  // CHECK: checked_cast_br any ClassBound in {{%.*}} : $any ClassBound to T
 }
 
 // CHECK-LABEL: sil hidden [ossa] @$s13generic_casts40opaque_existential_to_addr_only_concrete{{[_0-9a-zA-Z]*}}F
diff --git a/test/SILGen/hop_to_executor.swift b/test/SILGen/hop_to_executor.swift
index 63736dad7c1b6..a1daf20bed2c5 100644
--- a/test/SILGen/hop_to_executor.swift
+++ b/test/SILGen/hop_to_executor.swift
@@ -324,6 +324,8 @@ func testGlobalActorFuncValue(_ fn: @RedActor () -> Void) async {
 }
 
 func acceptAsyncSendableClosureInheriting<T>(@_inheritActorContext _: @Sendable () async -> T) { }
+func acceptAsyncSendableClosureAlwaysInheriting<T>(@_inheritActorContext(always) _: @Sendable () async -> T) { }
+func acceptAsyncSendableClosureAlwaysInheritingErased<T>(@_inheritActorContext(always) _: sending @isolated(any) () async -> T) { }
 
 extension MyActor {
   func synchronous() { }
@@ -338,6 +340,66 @@ extension MyActor {
       synchronous()
     }
   }
+
+  // CHECK-LABEL: sil private [ossa] @$s4test7MyActorC0A16AlwaysInheritingyyFyyYaYbXEfU_
+  // CHECK: debug_value [[SELF:%[0-9]+]] : $MyActor
+  // CHECK-NEXT: [[COPY:%[0-9]+]] = copy_value [[SELF]] : $MyActor
+  // CHECK-NEXT: [[BORROW:%[0-9]+]] = begin_borrow [[COPY]] : $MyActor
+  // CHECK-NEXT: hop_to_executor [[BORROW]] : $MyActor
+  func testAlwaysInheriting() {
+    acceptAsyncSendableClosureAlwaysInheriting {
+    }
+  }
+}
+
+func testIsolatedParameterWithInheritActorContext(_ isolation: isolated (any Actor)?) {
+  // CHECK-LABEL: sil private [ossa] @$s4test0A40IsolatedParameterWithInheritActorContextyyScA_pSgYiFyyYaYbXEfU_
+  // CHECK: debug_value [[ISOLATION:%[0-9]+]] : $Optional<any Actor>
+  // CHECK-NEXT: [[COPY:%[0-9]+]] = copy_value [[ISOLATION]] : $Optional<any Actor>
+  // CHECK-NEXT: [[BORROW:%[0-9]+]] = begin_borrow [[COPY]] : $Optional<any Actor>
+  // CHECK-NEXT: hop_to_executor [[BORROW]] : $Optional<any Actor>
+  acceptAsyncSendableClosureAlwaysInheriting {
+  }
+
+  // CHECK-LABEL: sil private [ossa] @$s4test0A40IsolatedParameterWithInheritActorContextyyScA_pSgYiFyyYaYbScMYcXEfU0_
+  // CHECK: hop_to_executor {{.*}} : $MainActor
+  acceptAsyncSendableClosureAlwaysInheriting { @MainActor in
+    // CHECK-LABEL: sil private [ossa] @$s4test0A40IsolatedParameterWithInheritActorContextyyScA_pSgYiFyyYaYbScMYcXEfU0_yyYaYbXEfU_
+    // CHECK: hop_to_executor {{.*}} : $MainActor
+    acceptAsyncSendableClosureAlwaysInheriting {
+    }
+  }
+
+  // CHECK-LABEL: sil private [ossa] @$s4test0A40IsolatedParameterWithInheritActorContextyyScA_pSgYiFyyYaYbXEfU1_
+  // CHECK: debug_value [[ISOLATION:%[0-9]+]] : $Optional<any Actor>
+  // CHECK-NEXT: [[COPY:%[0-9]+]] = copy_value [[ISOLATION]] : $Optional<any Actor>
+  // CHECK-NEXT: [[BORROW:%[0-9]+]] = begin_borrow [[COPY]] : $Optional<any Actor>
+  // CHECK-NEXT: hop_to_executor [[BORROW]] : $Optional<any Actor>
+  acceptAsyncSendableClosureAlwaysInheriting {
+    // CHECK-LABEL: sil private [ossa] @$s4test0A40IsolatedParameterWithInheritActorContextyyScA_pSgYiFyyYaYbXEfU1_yyYaYbXEfU_
+    // CHECK: debug_value [[ISOLATION:%[0-9]+]] : $Optional<any Actor>
+    // CHECK-NEXT: [[COPY:%[0-9]+]] = copy_value [[ISOLATION]] : $Optional<any Actor>
+    // CHECK-NEXT: [[BORROW:%[0-9]+]] = begin_borrow [[COPY]] : $Optional<any Actor>
+    // CHECK-NEXT: hop_to_executor [[BORROW]] : $Optional<any Actor>
+    acceptAsyncSendableClosureAlwaysInheriting {
+    }
+  }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s4test0a17IsolatedParamWithB3AnyyyScA_pYiF
+// CHECK: [[CLOSURE_REF:%.*]] = function_ref @$s4test0a17IsolatedParamWithB3AnyyyScA_pYiFyyYaXEfU_
+// CHECK-NEXT: [[ISOLATION_COPY_1:%.*]] = copy_value %0 : $any Actor
+// CHECK-NEXT: [[ISOLATION_COPY_2:%.*]] = copy_value [[ISOLATION_COPY_1]] : $any Actor
+// CHECK-NEXT: [[DYNAMIC_ISOLATION:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[ISOLATION_COPY_2]] : $any Actor
+// CHECK-NEXT: [[CLOSURE_WITH_APPLIED_ISOLATION:%.*]] = partial_apply [callee_guaranteed] [isolated_any] [[CLOSURE_REF]]([[DYNAMIC_ISOLATION]], [[ISOLATION_COPY_1]])
+func testIsolatedParamWithIsolatedAny(_ isolation: isolated any Actor) {
+  // CHECK-LABEL: sil private [ossa] @$s4test0a17IsolatedParamWithB3AnyyyScA_pYiFyyYaXEfU_
+  // CHECK: bb0(%0 : $*(), [[DYNAMIC_ISOLATION:%[0-9]+]] : @guaranteed $Optional<any Actor>, [[CAPTURED_ISOLATION:%[0-9]+]] : @closureCapture @guaranteed $any Actor):
+  // CHECK: [[COPY:%[0-9]+]] = copy_value [[CAPTURED_ISOLATION]] : $any Actor
+  // CHECK-NEXT: [[BORROW:%[0-9]+]] = begin_borrow [[COPY]] : $any Actor
+  // CHECK-NEXT: hop_to_executor [[BORROW]] : $any Actor
+  acceptAsyncSendableClosureAlwaysInheritingErased {
+  }
 }
 
 func acceptAsyncClosure(_: () async -> Void) { }
diff --git a/test/SILGen/if_guard_addressable.swift b/test/SILGen/if_guard_addressable.swift
new file mode 100644
index 0000000000000..9ab6e680df21f
--- /dev/null
+++ b/test/SILGen/if_guard_addressable.swift
@@ -0,0 +1,19 @@
+// RUN: %target-swift-emit-silgen -enable-experimental-feature AddressableParameters %s 
+
+// REQUIRES: swift_feature_AddressableParameters
+
+struct Foo {}
+
+func foo(_: borrowing @_addressable Foo) {}
+
+func bar() -> (Foo, Int)? { return nil }
+
+func test1() {
+	guard let (f, i) = bar() else {return}
+	
+	foo(f)
+}
+
+func test2() {
+	if let (f, i) = bar() {foo(f)} else {}
+}
diff --git a/test/SILGen/init_delegation_optional.swift b/test/SILGen/init_delegation_optional.swift
index 385977177249f..ea0020dcc1a19 100644
--- a/test/SILGen/init_delegation_optional.swift
+++ b/test/SILGen/init_delegation_optional.swift
@@ -369,7 +369,7 @@ extension Optional where Wrapped == Optional<Bool> {
     // CHECK-NEXT: [[PB:%[0-9]+]] = project_box [[MARKED_SELF_LIFETIME]]
     // CHECK: [[RESULT_ADDR:%[0-9]+]] = alloc_stack $Optional<Optional<Bool>>
     // CHECK: [[DELEG_INIT:%[0-9]+]] = function_ref @$sSq24init_delegation_optionalE12nonFailable1xSgyt_tcfC
-    // CHECK-NEXT: apply [[DELEG_INIT]]<Bool?>([[RESULT_ADDR]], [[SELF_META]])
+    // CHECK-NEXT: apply [[DELEG_INIT]]<Optional<Bool>>([[RESULT_ADDR]], [[SELF_META]])
     // CHECK-NEXT: [[RESULT:%[0-9]+]] = load [trivial] [[RESULT_ADDR]]
     // CHECK-NEXT: assign [[RESULT]] to [[PB]]
     // CHECK-NEXT: dealloc_stack [[RESULT_ADDR]]
diff --git a/test/SILGen/inlinable_attribute.swift b/test/SILGen/inlinable_attribute.swift
index cec097afb8fba..d924aa2a1fcf8 100644
--- a/test/SILGen/inlinable_attribute.swift
+++ b/test/SILGen/inlinable_attribute.swift
@@ -39,8 +39,9 @@ public class MyCls {
 }
 
 public actor MyAct {
-  // CHECK-LABEL-NOT: sil [serialized] [ossa] @$s19inlinable_attribute5MyActCfZ : $@convention(thin) (@owned MyAct) -> ()
+  // CHECK-NOT: sil [serialized] [ossa] @$s19inlinable_attribute5MyActCfZ : $@convention(thin) (@owned MyAct) -> ()
   // CHECK-LABEL: sil [serialized] [ossa] @$s19inlinable_attribute5MyActCfD : $@convention(method) (@owned MyAct) -> ()
+  // CHECK-NOT: sil [serialized] [ossa] @$s19inlinable_attribute5MyActCfZ : $@convention(thin) (@owned MyAct) -> ()
   @inlinable deinit {}
 
   /// whether delegating or not, the initializers for an actor are not serialized unless marked inlinable.
diff --git a/test/SILGen/inline_always.swift b/test/SILGen/inline_always.swift
index af600c2fff8f1..9fa11c0573cf4 100644
--- a/test/SILGen/inline_always.swift
+++ b/test/SILGen/inline_always.swift
@@ -1,39 +1,72 @@
-// RUN: %target-swift-emit-silgen -parse-as-library %s | %FileCheck %s
+// RUN: %target-swift-emit-silgen -enable-experimental-feature InlineAlways -parse-as-library %s | %FileCheck %s
 
-// CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always0b1_A7_calleeyyF : $@convention(thin) () -> ()
+// REQUIRES: swift_feature_InlineAlways
+
+// CHECK-LABEL: sil hidden [heuristic_always_inline] [ossa] @$s13inline_always0b1_A7_calleeyyF : $@convention(thin) () -> ()
 @inline(__always)
 func always_inline_callee() {}
 
-// CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always11testClosureyyF
+// CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always0b1_A8_callee2yyF : $@convention(thin) () -> ()
+@inline(always)
+func always_inline_callee2() {}
+
+// CHECK-LABEL: sil hidden [heuristic_always_inline] [ossa] @$s13inline_always11testClosureyyF
 @inline(__always)
 func testClosure() {
-  // CHECK-LABEL: sil private [always_inline] [ossa] @$s13inline_always11testClosureyyFyycfU_
+  // CHECK-LABEL: sil private [heuristic_always_inline] [ossa] @$s13inline_always11testClosureyyFyycfU_
+  _ = { }
+}
+// CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always12testClosure2yyF
+@inline(always)
+func testClosure2() {
+  // CHECK-LABEL: sil private [always_inline] [ossa] @$s13inline_always12testClosure2yyFyycfU_
   _ = { }
 }
-
 protocol AlwaysInline {
   func alwaysInlined()
 }
 
 struct AlwaysInlinedMember : AlwaysInline {
-  // CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberV0bD0yyF : $@convention(method) (AlwaysInlinedMember) -> () {
+  // CHECK-LABEL: sil hidden [heuristic_always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberV0bD0yyF : $@convention(method) (AlwaysInlinedMember) -> () {
   @inline(__always)
   func alwaysInlined() {}
 
   @inline(__always)
   var alwaysInlinedVar: Int {
-    // CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberV0bD3VarSivg : $@convention(method) (AlwaysInlinedMember) -> Int
+    // CHECK-LABEL: sil hidden [heuristic_always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberV0bD3VarSivg : $@convention(method) (AlwaysInlinedMember) -> Int
     get { return 0 }
 
-    // CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberV0bD3VarSivs : $@convention(method) (Int, @inout AlwaysInlinedMember) -> ()
+    // CHECK-LABEL: sil hidden [heuristic_always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberV0bD3VarSivs : $@convention(method) (Int, @inout AlwaysInlinedMember) -> ()
     set { }
   }
 
-  // CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberV0bD6GetterSivg : $@convention(method) (AlwaysInlinedMember) -> Int
+  // CHECK-LABEL: sil hidden [heuristic_always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberV0bD6GetterSivg : $@convention(method) (AlwaysInlinedMember) -> Int
   var alwaysInlinedGetter: Int {
     @inline(__always)
     get { return 0 }
   }
 }
 
-// CHECK-LABEL: sil private [transparent] [thunk] [always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberVAA0C6InlineA2aDP0bD0yyFTW : $@convention(witness_method: AlwaysInline) (@in_guaranteed AlwaysInlinedMember) -> () {
+// CHECK-LABEL: sil private [transparent] [thunk] [heuristic_always_inline] [ossa] @$s13inline_always19AlwaysInlinedMemberVAA0C6InlineA2aDP0bD0yyFTW : $@convention(witness_method: AlwaysInline) (@in_guaranteed AlwaysInlinedMember) -> () {
+
+struct AlwaysInlinedMember2 : AlwaysInline {
+  // CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always20AlwaysInlinedMember2V0bD0yyF : $@convention(method) (AlwaysInlinedMember2) -> () {
+  @inline(always)
+  func alwaysInlined() {}
+
+  @inline(always)
+  var alwaysInlinedVar: Int {
+    // CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always20AlwaysInlinedMember2V0bD3VarSivg : $@convention(method) (AlwaysInlinedMember2) -> Int
+    get { return 0 }
+
+    // CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always20AlwaysInlinedMember2V0bD3VarSivs : $@convention(method) (Int, @inout AlwaysInlinedMember2) -> ()
+    set { }
+  }
+
+  // CHECK-LABEL: sil hidden [always_inline] [ossa] @$s13inline_always20AlwaysInlinedMember2V0bD6GetterSivg : $@convention(method) (AlwaysInlinedMember2) -> Int
+  var alwaysInlinedGetter: Int {
+    @inline(always)
+    get { return 0 }
+  }
+}
+// CHECK-LABEL: sil private [transparent] [thunk] [heuristic_always_inline] [ossa] @$s13inline_always20AlwaysInlinedMember2VAA0C6InlineA2aDP0bD0yyFTW : $@convention(witness_method: AlwaysInline) (@in_guaranteed AlwaysInlinedMember2) -> () {
diff --git a/test/SILGen/inlinearray_literal.swift b/test/SILGen/inlinearray_literal.swift
index c48a3dbf35a3d..26becddbe69ab 100644
--- a/test/SILGen/inlinearray_literal.swift
+++ b/test/SILGen/inlinearray_literal.swift
@@ -37,7 +37,8 @@ func emptyNoncopyable() -> InlineArray<0, Atomic<Int>> {
 
 // CHECK-LABEL: sil{{.*}} @$s19inlinearray_literal7trivials11InlineArrayVy$3_SiGyF : $@convention(thin) () -> InlineArray<4, Int> {
 // CHECK:         [[SLAB_ALLOC:%.*]] = alloc_stack $InlineArray<4, Int>
-// CHECK-NEXT:    [[ELEMENT_PTR:%.*]] = unchecked_addr_cast [[SLAB_ALLOC]] to $*Int
+// CHECK-NEXT:    [[SE:%.*]] = struct_element_addr [[SLAB_ALLOC]], #InlineArray._storage
+// CHECK-NEXT:    [[ELEMENT_PTR:%.*]] = vector_base_addr [[SE]]
 // CHECK-NEXT:    [[ELT_0_LITERAL:%.*]] = integer_literal $Builtin.IntLiteral, 1
 // CHECK:         [[ELT_0:%.*]] = apply {{%.*}}([[ELT_0_LITERAL]], {{%.*}}) : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int
 // CHECK-NEXT:    store [[ELT_0]] to [trivial] [[ELEMENT_PTR]]
@@ -66,7 +67,8 @@ func trivial() -> InlineArray<4, Int> {
 
 // CHECK-LABEL: sil{{.*}} @$s19inlinearray_literal10nontrivials11InlineArrayVy$1_SSGyF : $@convention(thin) () -> @owned InlineArray<2, String> {
 // CHECK:         [[SLAB_ALLOC:%.*]] = alloc_stack $InlineArray<2, String>
-// CHECK-NEXT:    [[ELEMENT_PTR:%.*]] = unchecked_addr_cast [[SLAB_ALLOC]] to $*String
+// CHECK-NEXT:    [[SE:%.*]] = struct_element_addr [[SLAB_ALLOC]], #InlineArray._storage
+// CHECK-NEXT:    [[ELEMENT_PTR:%.*]] = vector_base_addr [[SE]]
 // CHECK-NEXT:    [[ELT_0_LITERAL:%.*]] = string_literal utf8 "hello"
 // CHECK:         [[ELT_0:%.*]] = apply {{%.*}}([[ELT_0_LITERAL]], {{.*}}) : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
 // CHECK-NEXT:    store [[ELT_0]] to [init] [[ELEMENT_PTR]]
@@ -86,7 +88,8 @@ func nontrivial() -> InlineArray<2, String> {
 // CHECK-LABEL: sil{{.*}} @$s19inlinearray_literal11noncopyables11InlineArrayVy$1_15Synchronization6AtomicVySiGGyF : $@convention(thin) () -> @out InlineArray<2, Atomic<Int>> {
 // CHECK:       bb0([[SLAB_RETURN:%.*]] : $*InlineArray<2, Atomic<Int>>):
 // CHECK-NEXT:    [[SLAB_ALLOC:%.*]] = alloc_stack $InlineArray<2, Atomic<Int>>
-// CHECK-NEXT:    [[ELEMENT_PTR:%.*]] = unchecked_addr_cast [[SLAB_ALLOC]] to $*Atomic<Int>
+// CHECK-NEXT:    [[SE:%.*]] = struct_element_addr [[SLAB_ALLOC]], #InlineArray._storage
+// CHECK-NEXT:    [[ELEMENT_PTR:%.*]] = vector_base_addr [[SE]]
 // CHECK:         [[ATOMIC_INIT:%.*]] = function_ref @$s15Synchronization6AtomicVyACyxGxcfC
 // CHECK-NEXT:    [[ELT_0:%.*]] = apply [[ATOMIC_INIT]]<Int>([[ELEMENT_PTR]], {{.*}}) : $@convention(method) <τ_0_0 where τ_0_0 : AtomicRepresentable> (@in τ_0_0, @thin Atomic<τ_0_0>.Type) -> @out Atomic<τ_0_0>
 // CHECK:         [[ELT_1_OFFSET:%.*]] = integer_literal $Builtin.Word, 1
@@ -109,10 +112,11 @@ func noncopyable() -> InlineArray<2, Atomic<Int>> {
 
 // CHECK-LABEL: sil{{.*}} @$s19inlinearray_literal7closures11InlineArrayVy$0_S2icGyF : $@convention(thin) () -> @owned InlineArray<1, (Int) -> Int> {
 // CHECK:         [[IA_ALLOC:%.*]] = alloc_stack $InlineArray<1, (Int) -> Int>
-// CHECK-NEXT:    [[ADDR_CAST:%.*]] = unchecked_addr_cast [[IA_ALLOC]] to $*@callee_guaranteed @substituted <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0) -> @out τ_0_1 for <Int, Int>
+// CHECK-NEXT:    [[SE:%.*]] = struct_element_addr [[IA_ALLOC]], #InlineArray._storage
+// CHECK-NEXT:    [[ELEMENT_PTR:%.*]] = vector_base_addr [[SE]]
 // CHECK:         [[FN_REF:%.*]] = function_ref
 // CHECK-NEXT:    [[THIN_TO_THICK_FN:%.*]] = thin_to_thick_function [[FN_REF]] to $@callee_guaranteed @substituted <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0) -> @out τ_0_1 for <Int, Int>
-// CHECK-NEXT:    store [[THIN_TO_THICK_FN]] to [init] [[ADDR_CAST]]
+// CHECK-NEXT:    store [[THIN_TO_THICK_FN]] to [init] [[ELEMENT_PTR]]
 // CHECK-NEXT:    [[IA:%.*]] = load [take] [[IA_ALLOC]]
 // CHECK-NEXT:    dealloc_stack [[IA_ALLOC]]
 // CHECK-NEXT:    return [[IA]]
diff --git a/test/SILGen/isolated_default_arguments.swift b/test/SILGen/isolated_default_arguments.swift
new file mode 100644
index 0000000000000..627904e6330e7
--- /dev/null
+++ b/test/SILGen/isolated_default_arguments.swift
@@ -0,0 +1,163 @@
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -module-name test -Xllvm -sil-full-demangle -swift-version 6 %s | %FileCheck %s
+
+// We weren't adjusting offsets around isolated default arguments
+// properly, and it broke when presented with a non-isolated or
+// non-defaulted argument between two isolated default arguments.
+
+@MainActor
+func main_actor_int_x() -> Int {
+  return 0
+}
+
+@MainActor
+func main_actor_int_y() -> Int {
+  return 0
+}
+
+@MainActor
+func main_actor_int_z() -> Int {
+  return 0
+}
+
+@MainActor
+func main_actor_void() -> () {
+}
+
+@MainActor
+func main_actor_int_pair() -> (Int, Int) {
+  return (0,0)
+}
+
+func make_int(isolated isolation: (any Actor)? = #isolation) -> Int {
+  return 0
+}
+
+// This test breaks because the intermediate argument is `nil`, which
+// we treat as non-isolated.
+@MainActor
+func nonIsolatedDefaultArg(x: Int = main_actor_int_x(),
+                           y: Int? = nil,
+                           z: Int = main_actor_int_z()) {}
+
+// CHECK-LABEL: sil hidden [ossa] @$s4test0A21NonIsolatedDefaultArgyyYaF :
+// CHECK:         [[ARG1:%.*]] = enum $Optional<Int>, #Optional.none
+// CHECK:         hop_to_executor {{%.*}} : $MainActor
+// CHECK-NEXT:    // function_ref default argument 0 of
+// CHECK-NEXT:    [[ARG0FN:%.*]] = function_ref @$s4test21nonIsolatedDefaultArg1x1y1zySi_SiSgSitFfA_
+// CHECK-NEXT:    [[ARG0:%.*]] = apply [[ARG0FN]]()
+// CHECK-NEXT:    // function_ref default argument 2 of
+// CHECK-NEXT:    [[ARG2FN:%.*]] = function_ref @$s4test21nonIsolatedDefaultArg1x1y1zySi_SiSgSitFfA1_
+// CHECK-NEXT:    [[ARG2:%.*]] = apply [[ARG2FN]]()
+// CHECK-NEXT:    // function_ref test.nonIsolatedDefaultArg
+// CHECK-NEXT:    [[FN:%.*]] = function_ref @$s4test21nonIsolatedDefaultArg1x1y1zySi_SiSgSitF :
+// CHECK:         apply [[FN]]([[ARG0]], [[ARG1]], [[ARG2]])
+func testNonIsolatedDefaultArg() async {
+  await nonIsolatedDefaultArg()
+}
+
+// This test breaks because the intermediate argument is non-defaulted
+// and so gets evaluated in the non-delayed argument pass.
+@MainActor
+func isolatedDefaultArgs(x: Int = main_actor_int_x(),
+                         y: Int = main_actor_int_y(),
+                         z: Int = main_actor_int_z()) {}
+
+// CHECK-LABEL: sil hidden [ossa] @$s4test0A13NonDefaultArgyyYaF :
+// CHECK:         [[LITERAL_FN:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC :
+// CHECK-NEXT:    [[ARG1:%.*]] = apply [[LITERAL_FN]](
+// CHECK:         hop_to_executor {{%.*}} : $MainActor
+// CHECK-NEXT:    // function_ref default argument 0 of
+// CHECK-NEXT:    [[ARG0FN:%.*]] = function_ref @$s4test19isolatedDefaultArgs1x1y1zySi_S2itFfA_
+// CHECK-NEXT:    [[ARG0:%.*]] = apply [[ARG0FN]]()
+// CHECK-NEXT:    // function_ref default argument 2 of
+// CHECK-NEXT:    [[ARG2FN:%.*]] = function_ref @$s4test19isolatedDefaultArgs1x1y1zySi_S2itFfA1_
+// CHECK-NEXT:    [[ARG2:%.*]] = apply [[ARG2FN]]()
+// CHECK-NEXT:    // function_ref test.isolatedDefaultArgs
+// CHECK-NEXT:    [[FN:%.*]] = function_ref @$s4test19isolatedDefaultArgs1x1y1zySi_S2itF :
+// CHECK:         apply [[FN]]([[ARG0]], [[ARG1]], [[ARG2]])
+func testNonDefaultArg() async {
+  await isolatedDefaultArgs(y: 0)
+}
+
+// Exercise our handling of isolated default arguments that expand to
+// empty or multiple arguments.
+@MainActor
+func voidIsolatedDefaultArg(x: () = main_actor_void(),
+                            y: Int = main_actor_int_y(),
+                            z: Int = main_actor_int_z()) {}
+
+// CHECK-LABEL: sil hidden [ossa] @$s4test0A22VoidIsolatedDefaultArgyyYaF :
+// CHECK:         [[LITERAL_FN:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC :
+// CHECK-NEXT:    [[ARG1:%.*]] = apply [[LITERAL_FN]](
+// CHECK:         hop_to_executor {{%.*}} : $MainActor
+// CHECK-NEXT:    // function_ref default argument 0 of
+// CHECK-NEXT:    [[ARG0FN:%.*]] = function_ref @$s4test22voidIsolatedDefaultArg1x1y1zyyt_S2itFfA_
+// CHECK-NEXT:    [[ARG0:%.*]] = apply [[ARG0FN]]()
+// CHECK-NEXT:    // function_ref default argument 2 of
+// CHECK-NEXT:    [[ARG2FN:%.*]] = function_ref @$s4test22voidIsolatedDefaultArg1x1y1zyyt_S2itFfA1_
+// CHECK-NEXT:    [[ARG2:%.*]] = apply [[ARG2FN]]()
+// CHECK-NEXT:    // function_ref test.voidIsolatedDefaultArg
+// CHECK-NEXT:    [[FN:%.*]] = function_ref @$s4test22voidIsolatedDefaultArg1x1y1zyyt_S2itF :
+// CHECK:         apply [[FN]]([[ARG1]], [[ARG2]])
+func testVoidIsolatedDefaultArg() async {
+  await voidIsolatedDefaultArg(y: 0)
+}
+
+@MainActor
+func tupleIsolatedDefaultArg(x: (Int,Int) = main_actor_int_pair(),
+                             y: Int = main_actor_int_y(),
+                             z: Int = main_actor_int_z()) {}
+
+// CHECK-LABEL: sil hidden [ossa] @$s4test0A23TupleIsolatedDefaultArgyyYaF :
+// CHECK:         [[LITERAL_FN:%.*]] = function_ref @$sSi22_builtinIntegerLiteralSiBI_tcfC :
+// CHECK-NEXT:    [[ARG1:%.*]] = apply [[LITERAL_FN]](
+// CHECK:         hop_to_executor {{%.*}} : $MainActor
+// CHECK-NEXT:    // function_ref default argument 0 of
+// CHECK-NEXT:    [[ARG0FN:%.*]] = function_ref @$s4test23tupleIsolatedDefaultArg1x1y1zySi_Sit_S2itFfA_
+// CHECK-NEXT:    [[ARG0:%.*]] = apply [[ARG0FN]]()
+// CHECK-NEXT:    ([[ARG0_0:%.*]], [[ARG0_1:%.*]]) = destructure_tuple [[ARG0]] : $(Int, Int)
+// CHECK-NEXT:    // function_ref default argument 2 of
+// CHECK-NEXT:    [[ARG2FN:%.*]] = function_ref @$s4test23tupleIsolatedDefaultArg1x1y1zySi_Sit_S2itFfA1_
+// CHECK-NEXT:    [[ARG2:%.*]] = apply [[ARG2FN]]()
+// CHECK-NEXT:    // function_ref test.tupleIsolatedDefaultArg
+// CHECK-NEXT:    [[FN:%.*]] = function_ref @$s4test23tupleIsolatedDefaultArg1x1y1zySi_Sit_S2itF :
+// CHECK:         apply [[FN]]([[ARG0_0]], [[ARG0_1]], [[ARG1]], [[ARG2]])
+func testTupleIsolatedDefaultArg() async {
+  await tupleIsolatedDefaultArg(y: 0)
+}
+
+// When a function is caller-isolated, its default argument generators
+// should probably also be caller-isolated and forward their isolation
+// properly when #isolation is used. Currently, however, that's not what
+// we're doing, so test for the current behavior.
+
+nonisolated(nonsending)
+func callerIsolatedDefaultArg(x: Int = make_int()) async {}
+
+@MainActor
+func useCallerIsolatedDefaultArg() async {
+  await callerIsolatedDefaultArg()
+}
+
+//   Check that the default argument generator isn't caller-isolated.
+// CHECK-LABEL: // default argument 0 of test.callerIsolatedDefaultArg
+// CHECK-NEXT:  // Isolation: unspecified
+// CHECK-NEXT:  sil hidden [ossa] @$s4test24callerIsolatedDefaultArg1xySi_tYaFfA_ :
+// CHECK:       bb0:
+//   Check that we provide a nil isolation for #isolation
+// CHECK-NEXT:    [[NIL_ISOLATION:%.*]] = enum $Optional<any Actor>, #Optional.none
+// CHECK-NEXT:    // function_ref test.make_int
+// CHECK-NEXT:    [[FN:%.*]] = function_ref @$s4test8make_int8isolatedSiScA_pSg_tF :
+// CHECK-NEXT:    [[RESULT:%.*]] = apply [[FN]]([[NIL_ISOLATION]])
+// CHECK-NEXT:    return [[RESULT]]
+
+//   Check that we pass the right isolation to the generator.
+// CHECK-LABEL: sil hidden [ossa] @$s4test27useCallerIsolatedDefaultArgyyYaF :
+//   Get the main actor reference.
+// CHECK:         [[GET_MAIN_ACTOR:%.*]] = function_ref @$sScM6sharedScMvgZ :
+// CHECK-NEXT:    [[T0:%.*]] = apply [[GET_MAIN_ACTOR]](
+// CHECK-NEXT:    [[MAIN_ACTOR:%.*]] = begin_borrow [[T0]]
+//   Call the accessor.
+// CHECK:         // function_ref default argument 0 of
+// CHECK-NEXT:    [[GEN:%.*]] = function_ref @$s4test24callerIsolatedDefaultArg1xySi_tYaFfA_ :
+// CHECK-NEXT:    [[ARG:%.*]] = apply [[GEN]]()
diff --git a/test/SILGen/keypath_typed_throws.swift b/test/SILGen/keypath_typed_throws.swift
new file mode 100644
index 0000000000000..4fc9e02be99b5
--- /dev/null
+++ b/test/SILGen/keypath_typed_throws.swift
@@ -0,0 +1,8 @@
+// RUN: %target-swift-emit-silgen %s
+// RUN: %target-swift-emit-silgen %s -enable-library-evolution
+// RUN: %target-swift-emit-silgen %s -enable-testing
+// RUN: %target-swift-emit-silgen %s -enable-library-evolution -enable-testing
+
+public struct Visitor<Node, Failure: Error> {
+  public var visit: (Node) throws(Failure) -> Void
+}
diff --git a/test/SILGen/keypaths.swift b/test/SILGen/keypaths.swift
index 2fab1f5de3a51..dd22fa102abd1 100644
--- a/test/SILGen/keypaths.swift
+++ b/test/SILGen/keypaths.swift
@@ -738,11 +738,11 @@ class M {
 // CHECK-LABEL: // test_metatype_keypaths()
 // CHECK-LABEL: sil hidden [ossa] @{{.*}} : $@convention(thin) () -> () {
 func test_metatype_keypaths() {
-  // CHECK: keypath $ReferenceWritableKeyPath<M.Type, Int>, (root $M.Type; settable_property $Int, id @$s8keypaths1MC10chanceRainSivgZ : $@convention(method) (@thick M.Type) -> Int, getter @$s8keypaths1MC10chanceRainSivpZACmTK : $@convention(keypath_accessor_getter) (@in_guaranteed @thick M.Type) -> @out Int, setter @$s8keypaths1MC10chanceRainSivpZACmTk : $@convention(keypath_accessor_setter) (@in_guaranteed Int, @in_guaranteed @thick M.Type) -> ())
+  // CHECK: keypath $KeyPath<M.Type, Int>, (root $M.Type; settable_property $Int, id @$s8keypaths1MC10chanceRainSivgZ : $@convention(method) (@thick M.Type) -> Int, getter @$s8keypaths1MC10chanceRainSivpZACmTK : $@convention(keypath_accessor_getter) (@in_guaranteed @thick M.Type) -> @out Int, setter @$s8keypaths1MC10chanceRainSivpZACmTk : $@convention(keypath_accessor_setter) (@in_guaranteed Int, @in_guaranteed @thick M.Type) -> ())
   let _: KeyPath<M.Type, Int> = \M.Type.chanceRain
   // CHECK: keypath $KeyPath<M.Type, Bool>, (root $M.Type; gettable_property $Bool, id @$s8keypaths1MC7isSunnySbvgZ : $@convention(method) (@thick M.Type) -> Bool, getter @$s8keypaths1MC7isSunnySbvpZACmTK : $@convention(keypath_accessor_getter) (@in_guaranteed @thick M.Type) -> @out Bool)
   let _: KeyPath<M.Type, Bool> = \M.Type.isSunny
-  // CHECK: keypath $ReferenceWritableKeyPath<M.Type, Bool>, (root $M.Type; settable_property $Bool, id @$s8keypaths1MC8isCloudySbvgZ : $@convention(method) (@thick M.Type) -> Bool, getter @$s8keypaths1MC8isCloudySbvpZACmTK : $@convention(keypath_accessor_getter) (@in_guaranteed @thick M.Type) -> @out Bool, setter @$s8keypaths1MC8isCloudySbvpZACmTk : $@convention(keypath_accessor_setter) (@in_guaranteed Bool, @in_guaranteed @thick M.Type) -> ())
+  // CHECK: keypath $KeyPath<M.Type, Bool>, (root $M.Type; settable_property $Bool, id @$s8keypaths1MC8isCloudySbvgZ : $@convention(method) (@thick M.Type) -> Bool, getter @$s8keypaths1MC8isCloudySbvpZACmTK : $@convention(keypath_accessor_getter) (@in_guaranteed @thick M.Type) -> @out Bool, setter @$s8keypaths1MC8isCloudySbvpZACmTk : $@convention(keypath_accessor_setter) (@in_guaranteed Bool, @in_guaranteed @thick M.Type) -> ())
   let _: KeyPath<M.Type, Bool> = \M.Type.isCloudy
   // CHECK: keypath $KeyPath<M.Type, String>, (root $M.Type; gettable_property $String, id @$s8keypaths1MCySSSicigZ : $@convention(method) (Int, @thick M.Type) -> @owned String, getter @$s8keypaths1MCySSSicipZACmTK : $@convention(keypath_accessor_getter) (@in_guaranteed @thick M.Type, @in_guaranteed Int) -> @out String, indices [%$0 : $Int : $Int], indices_equals @$sSiTH : $@convention(keypath_accessor_equals) (@in_guaranteed Int, @in_guaranteed Int) -> Bool, indices_hash @$sSiTh : $@convention(keypath_accessor_hash) (@in_guaranteed Int) -> Int) (%{{.*}})
   let _: KeyPath<M.Type, String> = \M.Type.[2]
@@ -805,3 +805,24 @@ protocol HasAlias {
 func testHasAlias() {
   _ = \HasAlias.id
 }
+
+// https://github.com/swiftlang/swift/issues/80669
+func type<Root, Value>(at keyPath: KeyPath<Root, Value>) -> Value.Type {
+  return Value.self
+}
+
+class DynamicSelfTypeTestClass {
+  var other = DynamicSelfTypeTestClass()
+
+  static func staticFunc() {
+    type(at: \Self.other).bar()
+  }
+
+  static func bar() {
+    print("Hello")
+  }
+}
+
+func testDynamicSelfType() {
+  DynamicSelfTypeTestClass.staticFunc()
+}
diff --git a/test/SILGen/lifetime_dependence_lowering.swift b/test/SILGen/lifetime_dependence_lowering.swift
index 56c7fd9986396..23c944e62ae4e 100644
--- a/test/SILGen/lifetime_dependence_lowering.swift
+++ b/test/SILGen/lifetime_dependence_lowering.swift
@@ -1,6 +1,6 @@
-// RUN: %target-swift-emit-silgen -enable-experimental-feature LifetimeDependence -enable-experimental-feature AddressableParameters -enable-experimental-feature AddressableTypes %s | %FileCheck %s
+// RUN: %target-swift-emit-silgen -enable-experimental-feature Lifetimes -enable-experimental-feature AddressableParameters -enable-experimental-feature AddressableTypes %s | %FileCheck %s
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_AddressableParameters
 // REQUIRES: swift_feature_AddressableTypes
 
@@ -9,81 +9,81 @@ struct Foo: ~Escapable { }
 struct Butt {
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}5test1{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 1) @owned Foo
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func test1(other: Butt) -> Foo {
     }
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}5test2{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 0) @owned Foo
-    @lifetime(borrow other)
+    @_lifetime(borrow other)
     func test2(other: Butt) -> Foo {
     }
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}5test3{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 4) @owned Foo
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func test3(other: Butt, tuple: (Butt, Butt), another: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}5test4{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 0) @owned Foo
-    @lifetime(borrow other)
+    @_lifetime(borrow other)
     func test4(other: Butt, tuple: (Butt, Butt), another: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}5test5{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 1, borrow 2) @owned Foo
-    @lifetime(borrow tuple)
+    @_lifetime(borrow tuple)
     func test5(other: Butt, tuple: (Butt, Butt), another: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}5test6{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 3) @owned Foo
-    @lifetime(borrow another)
+    @_lifetime(borrow another)
     func test6(other: Butt, tuple: (Butt, Butt), another: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}5test7{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 2) @owned Foo
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func test7(other: Butt, nothing: (), another: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}5test8{{.*}} : $
     // CHECK-SAME: -> @lifetime(immortal) @owned Foo
-    @lifetime(borrow nothing)
+    @_lifetime(borrow nothing)
     func test8(other: Butt, nothing: (), another: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}5test9{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 0) @owned Foo
-    @lifetime(borrow other)
+    @_lifetime(borrow other)
     func test9(other: Butt, nothing: (), another: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}6test10{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 1) @owned Foo
-    @lifetime(borrow another)
+    @_lifetime(borrow another)
     func test10(other: Butt, nothing: (), another: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}6test11{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow address 1) @owned Foo
     @_addressableSelf
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func test11(other: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}6test12{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 0) @owned Foo
     @_addressableSelf
-    @lifetime(borrow other)
+    @_lifetime(borrow other)
     func test12(other: Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}6test13{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow 1) @owned Foo
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func test13(other: @_addressable Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}6test14{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow address 0) @owned Foo
-    @lifetime(borrow other)
+    @_lifetime(borrow other)
     func test14(other: @_addressable Butt) -> Foo {}
 
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}6test15{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow address 0) @owned Foo
-    @lifetime(borrow tuple)
+    @_lifetime(borrow tuple)
     func test15(tuple: @_addressable (Butt, Butt)) -> Foo {}
 }
 
@@ -91,21 +91,21 @@ struct Butt {
 struct AddressableForDeps {
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}6test16{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow address_for_deps 3) @owned Foo
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     func test16(tuple: (AddressableForDeps, AddressableForDeps),
                 other: AddressableForDeps) -> Foo {}
 
     // The dependency makes the tuple pass as a single indirect argument.
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}6test17{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow address_for_deps 0) @owned Foo
-    @lifetime(borrow tuple)
+    @_lifetime(borrow tuple)
     func test17(tuple: (AddressableForDeps, AddressableForDeps),
                 other: AddressableForDeps) -> Foo {}
 
     // The tuple destructures as usual, but `other` is passed indirectly.
     // CHECK-LABEL: sil{{.*}} @$s{{.*}}6test18{{.*}} : $
     // CHECK-SAME: -> @lifetime(borrow address_for_deps 2) @owned Foo
-    @lifetime(borrow other)
+    @_lifetime(borrow other)
     func test18(tuple: (AddressableForDeps, AddressableForDeps),
                 other: AddressableForDeps) -> Foo {}
 }
diff --git a/test/SILGen/local_function_isolation.swift b/test/SILGen/local_function_isolation.swift
index 87bea9eff70f8..52825635aa2eb 100644
--- a/test/SILGen/local_function_isolation.swift
+++ b/test/SILGen/local_function_isolation.swift
@@ -73,7 +73,7 @@ actor DeferInsideInitActor {
   init(foo: ()) async throws {
     // CHECK-LABEL: sil private [ossa] @$s24local_function_isolation20DeferInsideInitActorC3fooACyt_tYaKcfc6$deferL_yyF : $@convention(thin) () -> () {
     defer {}
-    try self.init()
+    self.init()
   }
 }
 
diff --git a/test/SILGen/manual_ownership.swift b/test/SILGen/manual_ownership.swift
new file mode 100644
index 0000000000000..b18403eca9813
--- /dev/null
+++ b/test/SILGen/manual_ownership.swift
@@ -0,0 +1,96 @@
+// RUN: %target-swift-frontend %s -emit-silgen -verify -sil-verify-all \
+// RUN:   -enable-experimental-feature ManualOwnership -o %t.silgen
+
+// RUN: %FileCheck %s --input-file %t.silgen
+
+// REQUIRES: swift_feature_ManualOwnership
+
+class ShapeClass {}
+class TriangleClass {
+  var shape = ShapeClass()
+}
+
+// CHECK-LABEL: sil {{.*}} @basic_access_of_loadable
+// CHECK:       bb0(%0 : @guaranteed $TriangleClass):
+// CHECK-NEXT:    debug_value %0
+// CHECK-NEXT:    [[M:%.*]] = class_method %0, #TriangleClass.shape!getter
+// CHECK-NEXT:    [[SHAPE:%.*]] = apply [[M]](%0)
+// CHECK-NEXT:    [[COPY:%.*]] = explicit_copy_value [[SHAPE]]
+// CHECK-NEXT:    destroy_value [[SHAPE]]
+// CHECK-NEXT:    return [[COPY]]
+// CHECK-NEXT:  } // end sil function 'basic_access_of_loadable'
+@_manualOwnership
+@_silgen_name("basic_access_of_loadable")
+func basic_access_of_loadable(_ t: TriangleClass) -> ShapeClass {
+  return copy t.shape
+}
+
+// CHECK-LABEL: sil {{.*}} @var_assign
+// CHECK:          alloc_box ${ var TriangleClass }, var, name "x"
+// CHECK-NEXT:     begin_borrow [lexical] [var_decl]
+// CHECK-NEXT:     [[VAR:%.*]] = project_box {{.*}}, 0
+// CHECK:         bb1:
+// CHECK-NEXT:      [[T_COPY:%.*]] = explicit_copy_value %0
+// CHECK-NEXT:      [[ADDR1:%.*]] = begin_access [modify] [unknown] [[VAR]]
+// CHECK-NEXT:      assign [[T_COPY]] to [[ADDR1]]
+// CHECK-NEXT:      end_access [[ADDR1]]
+// CHECK:         bb3:
+// CHECK-NEXT:      [[ADDR2:%.*]] = begin_access [read] [unknown] [[VAR]]
+// CHECK-NEXT:      [[LOAD:%.*]] = load [copy] [[ADDR2]]
+// CHECK-NEXT:      [[X_COPY:%.*]] = explicit_copy_value [[LOAD]]
+// CHECK-NEXT:      end_access [[ADDR2]]
+// CHECK:           return [[X_COPY]]
+// CHECK-NEXT:    } // end sil function 'var_assign'
+@_manualOwnership
+@_silgen_name("var_assign")
+func var_assign(_ t: TriangleClass, _ b: Bool) -> TriangleClass {
+  var x = TriangleClass()
+  if b { x = copy t }
+  return copy x
+}
+
+// CHECK-LABEL: sil {{.*}} [manual_ownership] [ossa] @return_borrowed
+// CHECK:       bb0(%0 : @guaranteed $TriangleClass):
+// CHECK-NEXT:     debug_value %0
+// CHECK-NEXT:     [[IMPL_COPY:%.*]] = copy_value %0
+// CHECK-NEXT:     return [[IMPL_COPY]]
+// CHECK-NEXT:  } // end sil function 'return_borrowed'
+@_manualOwnership
+@_silgen_name("return_borrowed")
+func return_borrowed(_ t: borrowing TriangleClass) -> TriangleClass {
+  return t
+}
+
+// CHECK-LABEL: sil {{.*}} [manual_ownership] [ossa] @return_consumingParam
+// CHECK:       bb0(%0 : @_eagerMove @owned $TriangleClass):
+// CHECK-NEXT:     alloc_box ${ var TriangleClass }, var, name "t"
+// CHECK-NEXT:     begin_borrow [var_decl]
+// CHECK-NEXT:     [[ADDR:%.*]] = project_box {{.*}}, 0
+// CHECK-NEXT:     store %0 to [init] [[ADDR]]
+// CHECK-NEXT:     [[ACCESS:%.*]] = begin_access [read] [unknown] [[ADDR]]
+// CHECK-NEXT:     [[IMPL_COPY:%.*]] = load [copy] [[ACCESS]]
+// CHECK-NEXT:     end_access [[ACCESS]]
+// CHECK-NEXT:     end_borrow
+// CHECK-NEXT:     destroy_value
+// CHECK-NEXT:     return [[IMPL_COPY]]
+// CHECK-NEXT:  } // end sil function 'return_consumingParam'
+@_manualOwnership
+@_silgen_name("return_consumingParam")
+func return_consumingParam(_ t: consuming TriangleClass) -> TriangleClass {
+  return t
+}
+
+// CHECK-LABEL: sil {{.*}} [manual_ownership] [ossa] @return_owned
+// CHECK:       bb0(%0 : @owned $TriangleClass):
+// CHECK-NEXT:     debug_value %0
+// CHECK-NEXT:     [[BORROW:%.*]] = begin_borrow %0
+// CHECK-NEXT:     [[IMPL_COPY:%.*]] = copy_value [[BORROW]]
+// CHECK-NEXT:     end_borrow [[BORROW]]
+// CHECK-NEXT:     destroy_value %0
+// CHECK-NEXT:     return [[IMPL_COPY]]
+// CHECK-NEXT:  } // end sil function 'return_owned'
+@_manualOwnership
+@_silgen_name("return_owned")
+func return_owned(_ t: __owned TriangleClass) -> TriangleClass {
+  return t
+}
diff --git a/test/SILGen/moveonly.swift b/test/SILGen/moveonly.swift
index ac35c012bab77..93753fa499e3a 100644
--- a/test/SILGen/moveonly.swift
+++ b/test/SILGen/moveonly.swift
@@ -982,9 +982,13 @@ public struct LoadableSubscriptGetOnlyTester : ~Copyable {
 // CHECK: [[ACCESS:%.*]] = begin_access [read] [unknown] [[PROJECT]]
 // CHECK: [[MARK:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[ACCESS]]
 // CHECK: [[LOAD:%.*]] = load_borrow [unchecked] [[MARK]]
-// CHECK: apply {{%.*}}([[M2_PROJECT]], {{%.*}}, [[LOAD]])
+// CHECK: [[STACK_ALLOC:%.*]] = alloc_stack $AddressOnlyProtocol
+// CHECK: [[M_STACK_ALLOC:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[STACK_ALLOC]]
+// CHECK: apply {{%.*}}([[M_STACK_ALLOC]], {{%.*}}, [[LOAD]])
 // CHECK: end_borrow [[LOAD]]
 // CHECK: end_access [[ACCESS]]
+// CHECK: copy_addr [take] [[M_STACK_ALLOC]] to [init] [[M2_PROJECT]]
+// CHECK: dealloc_stack [[STACK_ALLOC]]
 // CHECK: [[M2_MARK:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[M2_PROJECT]]
 // CHECK: end_borrow [[M2_BORROW]]
 // CHECK: destroy_value [[M2_BOX]]
diff --git a/test/SILGen/moveonly_coroutine_access.swift b/test/SILGen/moveonly_coroutine_access.swift
new file mode 100644
index 0000000000000..dec67e3d0a9d6
--- /dev/null
+++ b/test/SILGen/moveonly_coroutine_access.swift
@@ -0,0 +1,124 @@
+// RUN: %target-swift-emit-silgen -DTRIVIAL %s | %FileCheck --check-prefix TRIVIAL %s
+// RUN: %target-swift-emit-sil -DTRIVIAL -sil-verify-all %s > /dev/null
+
+// RUN: %target-swift-emit-silgen -DLOADABLE %s | %FileCheck --check-prefix LOADABLE %s
+// RUN: %target-swift-emit-sil -DLOADABLE -sil-verify-all %s > /dev/null
+
+// RUN: %target-swift-emit-silgen -DADDRESS_ONLY %s | %FileCheck --check-prefix ADDRESS_ONLY %s
+// RUN: %target-swift-emit-sil -DADDRESS_ONLY -sil-verify-all %s > /dev/null
+
+class X {
+  let snc = SNC()
+}
+
+struct NC: ~Copyable {
+#if TRIVIAL
+  typealias T = Int
+  var x: T = 0
+#elseif LOADABLE
+  typealias T = X
+  var x: T = X()
+#elseif ADDRESS_ONLY
+  typealias T = Any
+  var x: T = X()
+#else
+#error("pick a mode")
+#endif
+
+  var consumingGetter: T {
+    consuming get { fatalError() }
+  }
+  var readCoroutine: T {
+    _read { yield x }
+  }
+  consuming func consumingFunc() -> T { fatalError() }
+  borrowing func borrowingFunc() -> T { fatalError() }
+
+  deinit { print("destroy") }
+}
+
+struct SNC: ~Copyable {
+  private var _data: NC = NC()
+
+  subscript(index: Int) -> NC {
+    _read { yield _data }
+    _modify { yield &_data }
+  }
+}
+
+func use(_ x: NC.T) {}
+
+
+// TRIVIAL-LABEL: sil hidden [ossa] @${{.*}}test_subscript_read3sncyAA3SNCV_tF : $@convention(thin) (@guaranteed SNC) -> () {
+// TRIVIAL:         ([[YIELDED:%.*]], [[HANDLE:%.*]]) = begin_apply
+// TRIVIAL:          [[COPY:%.*]] = copy_value [[YIELDED]]
+// TRIVIAL:          [[MARK:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[COPY]]
+// TRIVIAL:          [[BORROW_MARK:%.*]] = begin_borrow [[MARK]]
+// TRIVIAL:          [[X:%.*]] = struct_extract [[BORROW_MARK]], #NC.x
+// TRIVIAL:          end_borrow [[BORROW_MARK]]
+// TRIVIAL:          destroy_value [[MARK]]
+// TRIVIAL:          = end_apply [[HANDLE]] as $()
+// TRIVIAL:          = apply {{%.*}}([[X]])
+
+
+// LOADABLE-LABEL: sil hidden [ossa] @${{.*}}test_subscript_read3sncyAA3SNCV_tF : $@convention(thin) (@guaranteed SNC) -> () {
+// LOADABLE:         ([[YIELDED:%.*]], [[HANDLE:%.*]]) = begin_apply
+// LOADABLE:          [[COPY:%.*]] = copy_value [[YIELDED]]
+// LOADABLE:          [[MARK:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[COPY]]
+// LOADABLE:          [[BORROW_MARK:%.*]] = begin_borrow [[MARK]]
+// LOADABLE:          [[X:%.*]] = struct_extract [[BORROW_MARK]], #NC.x
+
+// LOADABLE:          [[X_COPY:%.*]] = copy_value [[X]]
+
+// LOADABLE:          end_borrow [[BORROW_MARK]]
+// LOADABLE:          destroy_value [[MARK]]
+// LOADABLE:          = end_apply [[HANDLE]] as $()
+
+// LOADABLE:          = apply {{%.*}}([[X_COPY]])
+
+
+
+// ADDRESS_ONLY-LABEL: sil hidden [ossa] @${{.*}}test_subscript_read3sncyAA3SNCV_tF : $@convention(thin) (@in_guaranteed SNC) -> () {
+// ADDRESS_ONLY:         ([[YIELDED:%.*]], [[HANDLE:%.*]]) = begin_apply
+
+// ADDRESS_ONLY:          [[MARK:%.*]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[YIELDED]]
+// ADDRESS_ONLY:          [[X_FIELD_ADDR:%.*]] = struct_element_addr [[MARK]], #NC.x
+// ADDRESS_ONLY:          [[X_LOCAL_ADDR:%.*]] = alloc_stack $Any
+// ADDRESS_ONLY:          copy_addr [[X_FIELD_ADDR]] to [init] [[X_LOCAL_ADDR]]
+// ADDRESS_ONLY:          = end_apply [[HANDLE]] as $()
+// ADDRESS_ONLY:          = apply {{%.*}}([[X_LOCAL_ADDR]])
+// ADDRESS_ONLY:          destroy_addr [[X_LOCAL_ADDR]]
+// ADDRESS_ONLY:          dealloc_stack [[X_LOCAL_ADDR]]
+
+func test_subscript_read(snc: borrowing SNC) {
+  use(snc[0].x)
+}
+
+
+struct SNC_OPT: ~Copyable {
+  private var _data: NC? = NC()
+
+  subscript(index: Int) -> NC? {
+    _read { yield _data }
+    _modify { yield &_data }
+  }
+}
+
+// LOADABLE-LABEL:  sil hidden [ossa] @${{.*}}test_subscript_write3sncyAA7SNC_OPTVz_tF
+
+// For the snc[0].take(), ensure the end_apply happens after the call to take.
+// LOADABLE:          begin_access [modify]
+// LOADABLE:          begin_apply
+// LOADABLE:          apply
+// LOADABLE:          end_apply
+// LOADABLE:          end_access
+
+// LOADABLE:          begin_access [modify]
+// LOADABLE:          begin_apply
+// LOADABLE:          assign
+// LOADABLE:          end_apply
+// LOADABLE:          end_access
+func test_subscript_write(snc: inout SNC_OPT) {
+  let x = snc[0].take()
+  snc[0] = x
+}
diff --git a/test/SILGen/moveonly_escaping_closure.swift b/test/SILGen/moveonly_escaping_closure.swift
index 864107017265b..9fc5def229be9 100644
--- a/test/SILGen/moveonly_escaping_closure.swift
+++ b/test/SILGen/moveonly_escaping_closure.swift
@@ -143,7 +143,7 @@ func testLocalLetClosureCaptureVar() {
         consumeVal(x) // expected-note {{consumed here}}
         // expected-note @-1 {{consumed again here}}
         borrowConsumeVal(x, x)
-        // expected-error @-1 {{overlapping accesses, but deinitialization requires exclusive access}}
+        // expected-error @-1 {{overlapping accesses to 'x', but deinitialization requires exclusive access}}
         // expected-note @-2 {{conflicting access is here}}
         // expected-note @-3 {{used here}}
         // expected-note @-4 {{used here}}
@@ -975,7 +975,7 @@ func testLocalLetClosureCaptureConsuming(_ x: consuming SingleElt) {
         consumeVal(x) // expected-note {{consumed here}}
         // expected-note @-1 {{consumed again here}}
         borrowConsumeVal(x, x) // expected-note {{used here}}
-        // expected-error @-1 {{overlapping accesses, but deinitialization requires exclusive access}}
+        // expected-error @-1 {{overlapping accesses to 'x', but deinitialization requires exclusive access}}
         // expected-note @-2 {{conflicting access is here}}
         // expected-note @-3 {{consumed here}}
         // expected-note @-4 {{used here}}
diff --git a/test/SILGen/noimplicitcopy_attr_arg_generic_users_banned.swift b/test/SILGen/noimplicitcopy_attr_arg_generic_users_banned.swift
index f63d7c8a5da10..fc8a6444ac8e6 100644
--- a/test/SILGen/noimplicitcopy_attr_arg_generic_users_banned.swift
+++ b/test/SILGen/noimplicitcopy_attr_arg_generic_users_banned.swift
@@ -10,24 +10,24 @@ struct MyStruct {
     // these are part of MyStruct.
     //
     // TODO: Make error specific for move only on struct/enum.
-    func foo<T>(@_noImplicitCopy _ t: T) { // expected-error {{@_noImplicitCopy can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
+    func foo<T>(@_noImplicitCopy _ t: T) { // expected-error {{'@_noImplicitCopy' can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
     }
 }
 
 struct MyGenericStruct<T> {
-    func foo(@_noImplicitCopy _ t: T) { // expected-error {{@_noImplicitCopy can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
+    func foo(@_noImplicitCopy _ t: T) { // expected-error {{'@_noImplicitCopy' can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
     }
 }
 
-func foo<T>(@_noImplicitCopy _ t: T) { // expected-error {{@_noImplicitCopy can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
+func foo<T>(@_noImplicitCopy _ t: T) { // expected-error {{'@_noImplicitCopy' can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
 }
 
 class MyClass {
-    func foo<T>(@_noImplicitCopy _ t: T) { // expected-error {{@_noImplicitCopy can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
+    func foo<T>(@_noImplicitCopy _ t: T) { // expected-error {{'@_noImplicitCopy' can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
     }
 }
 
 class MyGenericClass<T> {
-    func foo(@_noImplicitCopy _ t: T) { // expected-error {{@_noImplicitCopy can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
+    func foo(@_noImplicitCopy _ t: T) { // expected-error {{'@_noImplicitCopy' can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
     }
 }
diff --git a/test/SILGen/nonisolated_inherits_isolation.swift b/test/SILGen/nonisolated_inherits_isolation.swift
index f0fefae4da1a6..bb4c0a25fd939 100644
--- a/test/SILGen/nonisolated_inherits_isolation.swift
+++ b/test/SILGen/nonisolated_inherits_isolation.swift
@@ -1,8 +1,8 @@
-// RUN: %target-swift-emit-silgen -swift-version 6 -enable-experimental-feature AsyncCallerExecution %s | %FileCheck %s
+// RUN: %target-swift-emit-silgen -swift-version 6 -enable-upcoming-feature NonisolatedNonsendingByDefault %s | %FileCheck %s
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
-// REQUIRES: swift_feature_AsyncCallerExecution
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 //===----------------------------------------------------------------------===//
 //                             MARK: Declarations
@@ -151,3 +151,21 @@ class MainActorKlass {
     await unspecifiedAsyncUse(n)
   }
 }
+
+struct TestVarUse {
+  var test: Int {
+    // CHECK-LABEL: sil hidden [ossa] @$s30nonisolated_inherits_isolation10TestVarUseV4testSivg : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, TestVarUse) -> Int
+    get async {
+      42
+    }
+  }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s30nonisolated_inherits_isolation12testUseOfVar1tyAA04TestgE0V_tYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, TestVarUse) -> ()
+// CHECK: bb0([[ISOLATION:%.*]] : @guaranteed $Optional<any Actor>, [[BASE:%.*]] : $TestVarUse)
+// CHECK:   [[GETTER:%.*]] = function_ref @$s30nonisolated_inherits_isolation10TestVarUseV4testSivg : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, TestVarUse) -> Int
+// CHECK:   {{.*}} = apply [[GETTER]]([[ISOLATION]], [[BASE]])
+// CHECK: } // end sil function '$s30nonisolated_inherits_isolation12testUseOfVar1tyAA04TestgE0V_tYaF'
+func testUseOfVar(t: TestVarUse) async {
+  _ = await t.test
+}
diff --git a/test/SILGen/objc_async.swift b/test/SILGen/objc_async.swift
index ab9b2af44fb53..bf6eb7a038823 100644
--- a/test/SILGen/objc_async.swift
+++ b/test/SILGen/objc_async.swift
@@ -360,3 +360,31 @@ extension SlowServer: @retroactive FailableFloatLoader {
 // CHECK-NEXT:    [[ZERO_FLOAT:%.*]] = builtin "zeroInitializer"() : $Float
 // CHECK-NEXT:    [[BORROWED_SOME_NSERROR:%.*]] = begin_borrow [[SOME_NSERROR]] :
 // CHECK-NEXT:    apply [[BORROWED_BLOCK]]([[ZERO_FLOAT]], [[BORROWED_SOME_NSERROR]])
+
+// CHECK-LABEL: sil hidden [ossa] @$s10objc_async13testAnyObjectyySo10SlowServerCYaF : $@convention(thin) @async (@guaranteed SlowServer) -> () {
+// CHECK: bb0([[SLOWSERVER:%.*]] : @guaranteed $SlowServer):
+// CHECK: [[SLOWSERVER_C:%.*]] = copy_value [[SLOWSERVER]]
+// CHECK: [[SLOWSERVER_ANYOBJECT:%.*]] = init_existential_ref [[SLOWSERVER_C]]
+// CHECK: [[SLOWSERVER_ANYOBJECT_M:%.*]] = move_value [lexical] [var_decl] [[SLOWSERVER_ANYOBJECT]]
+// CHECK: debug_value [[SLOWSERVER_ANYOBJECT_M]] : $AnyObject, let, name "anyObjectSlowServer"
+// CHECK: [[SLOWSERVER_ANYOBJECT_M_B:%.*]] = begin_borrow [[SLOWSERVER_ANYOBJECT_M]]
+// CHECK: [[SLOWSERVER_ANYOBJECT_M_B_O:%.*]] = open_existential_ref [[SLOWSERVER_ANYOBJECT_M_B]]
+// CHECK: [[SLOWSERVER_ANYOBJECT_M_B_O_C:%.*]] = copy_value [[SLOWSERVER_ANYOBJECT_M_B_O]]
+// CHECK: [[METHOD:%.*]] = objc_method [[SLOWSERVER_ANYOBJECT_M_B_O_C]] : $@opened("{{.*}}", AnyObject) Self, #SlowServer.start!foreign : (SlowServer) -> (NSDate?) async -> (), $@convention(objc_method) (Optional<NSDate>, @convention(block) @Sendable () -> (), @opened("{{.*}}", AnyObject) Self) -> ()
+// CHECK: [[CONT:%.*]] = get_async_continuation_addr ()
+// CHECK: [[UNSAFE_CONT:%.*]] = struct $UnsafeContinuation<(), Never> ([[CONT]] : $Builtin.RawUnsafeContinuation)
+// CHECK: [[BLOCK:%.*]] = alloc_stack $@block_storage Any
+// CHECK: [[BLOCK_PROJECT:%.*]] = project_block_storage [[BLOCK]]
+// CHECK: [[BLOCK_PROJECT_EX:%.*]] = init_existential_addr [[BLOCK_PROJECT]]
+// CHECK: store [[UNSAFE_CONT]] to [trivial] [[BLOCK_PROJECT_EX]]
+// CHECK: merge_isolation_region [[BLOCK]] : $*@block_storage Any,
+// CHECK: [[CONT_HANDLER:%.*]] = function_ref @$sIeyBh_ytTz_ : $@convention(c) @Sendable (@inout_aliasable @block_storage Any) -> ()
+// CHECK: [[INIT_BLOCK_STORAGE_HEADER:%.*]] = init_block_storage_header [[BLOCK]] : $*@block_storage Any, invoke [[CONT_HANDLER]]
+// CHECK: merge_isolation_region [[SLOWSERVER_ANYOBJECT_M_B_O_C]] : $@opened("{{.*}}", AnyObject) Self, [[BLOCK]]
+// CHECK: apply [[METHOD]]({{%.*}}, [[INIT_BLOCK_STORAGE_HEADER]], [[SLOWSERVER_ANYOBJECT_M_B_O_C]])
+// CHECK: await_async_continuation [[CONT]] : $Builtin.RawUnsafeContinuation, resume bb1
+// CHECK: } // end sil function '$s10objc_async13testAnyObjectyySo10SlowServerCYaF'
+func testAnyObject(_ slowServer: SlowServer) async {
+  let anyObjectSlowServer: AnyObject = slowServer
+  await anyObjectSlowServer.start(at: nil)
+}
diff --git a/test/SILGen/objc_async_from_swift.swift b/test/SILGen/objc_async_from_swift.swift
index 41fd8ee90827d..6e8b2fc9b781c 100644
--- a/test/SILGen/objc_async_from_swift.swift
+++ b/test/SILGen/objc_async_from_swift.swift
@@ -1,6 +1,10 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -Xllvm -sil-print-types -emit-silgen -I %S/Inputs/custom-modules  -target %target-swift-5.1-abi-triple %s -verify | %FileCheck --implicit-check-not=hop_to_executor --check-prefix=CHECK --check-prefix=CHECK-%target-cpu %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -Xllvm -sil-print-types -emit-silgen -I %S/Inputs/custom-modules  -target %target-swift-5.1-abi-triple %s -verify | %FileCheck --implicit-check-not=hop_to_executor --check-prefix=CHECK --check-prefix=CHECK-%target-cpu --check-prefix CHECK-C %s
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-upcoming-feature NonisolatedNonsendingByDefault -Xllvm -sil-print-types -emit-silgen -I %S/Inputs/custom-modules  -target %target-swift-5.1-abi-triple %s -verify | %FileCheck --implicit-check-not=hop_to_executor --check-prefix=CHECK --check-prefix=CHECK-%target-cpu --check-prefix CHECK-NN %s
+
 // REQUIRES: concurrency
 // REQUIRES: objc_interop
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 import Foundation
 import ObjCConcurrency
@@ -15,42 +19,46 @@ import ObjCConcurrency
 
 // CHECK-LABEL: sil {{.*}}@{{.*}}15testSlowServing
 func testSlowServing(p: SlowServing) async throws {
-    // CHECK: [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK: hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK-NN: bb0([[HOP_TARGET:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C: [[HOP_TARGET:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+    // CHECK: hop_to_executor [[HOP_TARGET]] :
     // CHECK: objc_method {{.*}} $@convention(objc_method) <τ_0_0 where τ_0_0 : SlowServing> (@convention(block) (Int) -> (), τ_0_0) -> ()
-    // CHECK: hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK: hop_to_executor [[HOP_TARGET]] :
     let _: Int = await p.requestInt()
 
     // CHECK: objc_method {{.*}} $@convention(objc_method) <τ_0_0 where τ_0_0 : SlowServing> (@convention(block) (NSString) -> (), τ_0_0) -> ()
-    // CHECK: hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK: hop_to_executor [[HOP_TARGET]] :
     let _: String = await p.requestString()
 
     // CHECK: objc_method {{.*}} $@convention(objc_method) <τ_0_0 where τ_0_0 : SlowServing> (@convention(block) (Int, NSString) -> (), τ_0_0) -> ()
-    // CHECK: hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK: hop_to_executor [[HOP_TARGET]] :
     let _: (Int, String) = await p.requestIntAndString()
 
     // CHECK: objc_method {{.*}} $@convention(objc_method) <τ_0_0 where τ_0_0 : SlowServing> (@convention(block) (Int, Optional<NSString>, Optional<NSError>) -> (), τ_0_0) -> ()
-    // CHECK: hop_to_executor [[GENERIC_EXECUTOR]] :
-    // CHECK: hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK: hop_to_executor [[HOP_TARGET]] :
+    // CHECK: hop_to_executor [[HOP_TARGET]] :
     // CHECK-NEXT:      builtin "willThrow"
     let _: (Int, String) = try await p.tryRequestIntAndString()
 }
 
 // CHECK-LABEL: sil {{.*}}@{{.*}}20testSlowServingAgain
 func testSlowServingAgain(p: SlowServing) async throws {
-  // CHECK: [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-  // CHECK: hop_to_executor [[GENERIC_EXECUTOR]] :
+  // CHECK-NN: bb0([[HOP_TARGET:%.*]] : @guaranteed $Optional<any Actor>,
+  // CHECK-C: [[HOP_TARGET:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+  // CHECK: hop_to_executor [[HOP_TARGET]] :
   // CHECK: objc_method {{.*}} $@convention(objc_method) <τ_0_0 where τ_0_0 : SlowServing> (@convention(block) (Optional<NSString>, Optional<NSError>) -> (), τ_0_0) -> ()
-  // CHECK: hop_to_executor [[GENERIC_EXECUTOR]] :
-  // CHECK: hop_to_executor [[GENERIC_EXECUTOR]] :
+  // CHECK: hop_to_executor [[HOP_TARGET]] :
+  // CHECK: hop_to_executor [[HOP_TARGET]] :
   // CHECK-NEXT:      builtin "willThrow"
   let _: String = try await p.tryRequestString()
 }
 
 class SlowSwiftServer: NSObject, SlowServing {
     // CHECK-LABEL: sil {{.*}} @$s21objc_async_from_swift15SlowSwiftServerC10requestIntSiyYaF
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK-NN: bb0([[HOP_TARGET:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C:       [[HOP_TARGET:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+    // CHECK:         hop_to_executor [[HOP_TARGET]] :
+    // CHECK: } // end sil function '$s21objc_async_from_swift15SlowSwiftServerC10requestIntSiyYaF{{.*}}'
     // CHECK-LABEL: sil private {{.*}} @${{.*}}10requestInt{{.*}}To :
     // CHECK:         [[BLOCK_COPY:%.*]] = copy_block %0
     // CHECK:         [[SELF:%.*]] = copy_value %1
@@ -66,11 +74,13 @@ class SlowSwiftServer: NSObject, SlowServing {
     func requestInt() async -> Int { return 0 }
     func requestString() async -> String { return "" }
     // CHECK-LABEL: sil {{.*}} @$s21objc_async_from_swift15SlowSwiftServerC13requestStringSSyYaF
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK-NN:    bb0([[HOP_TARGET:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C:       [[HOP_TARGET:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+    // CHECK:         hop_to_executor [[HOP_TARGET]] :
     // CHECK-LABEL: sil {{.*}} @$s21objc_async_from_swift15SlowSwiftServerC16tryRequestStringSSyYaKF
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK-NN:    bb0([[HOP_TARGET:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C:       [[HOP_TARGET:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+    // CHECK:         hop_to_executor [[HOP_TARGET]] :
     // CHECK-LABEL: sil shared {{.*}} @${{.*}}16tryRequestString{{.*}}U_To :
     // CHECK:         [[BLOCK_COPY:%.*]] = copy_block %0
     // CHECK:         try_apply{{.*}}@async{{.*}}, normal [[NORMAL:bb[0-9]+]], error [[ERROR:bb[0-9]+]]
@@ -85,13 +95,15 @@ class SlowSwiftServer: NSObject, SlowServing {
     func tryRequestString() async throws -> String { return "" }
 
     // CHECK-LABEL: sil {{.*}} @$s21objc_async_from_swift15SlowSwiftServerC19requestIntAndStringSi_SStyYaF
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK-NN: bb0([[HOP_TARGET:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C:       [[HOP_TARGET:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+    // CHECK:         hop_to_executor [[HOP_TARGET]] :
     func requestIntAndString() async -> (Int, String) { return (0, "") }
 
     // CHECK-LABEL: sil {{.*}} @$s21objc_async_from_swift15SlowSwiftServerC22tryRequestIntAndStringSi_SStyYaKF
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
+    // CHECK-NN: bb0([[HOP_TARGET:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C:       [[HOP_TARGET:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
+    // CHECK:         hop_to_executor [[HOP_TARGET]] :
     func tryRequestIntAndString() async throws -> (Int, String) { return (0, "") }
 }
 
@@ -105,70 +117,292 @@ protocol NativelySlowServing {
 
 extension SlowServer: NativelySlowServing {}
 
+// protocol witness for NativelySlowServing.doSomethingSlow(_:) in conformance SlowServer
+//
+// CHECK-C-LABEL: sil private [transparent] [thunk] [ossa] @$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP011doSomethingA0ySiSSYaFTW : $@convention(witness_method: NativelySlowServing) @async (@guaranteed String, @in_guaranteed SlowServer) -> Int {
+// CHECK-C: bb0([[ARG:%.*]] : @guaranteed $String, [[SELF_ADDR:%.*]] : $*SlowServer):
+// CHECK-C:   [[SELF:%.*]] = load_borrow [[SELF_ADDR]]
+// CHECK-C:   [[FUNC:%.*]] = function_ref @$sSo10SlowServerC011doSomethingA0ySiSSYaFTO : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServer) -> Int
+// CHECK-C:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK-C:   hop_to_executor [[ACTOR]]
+// CHECK-C:   apply [[FUNC]]([[ACTOR]], [[ARG]], [[SELF]])
+// CHECK-C: } // end sil function '$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP011doSomethingA0ySiSSYaFTW'
+
+// CHECK-NN-LABEL: sil private [transparent] [thunk] [ossa] @$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP011doSomethingA0ySiSSYaFTW : $@convention(witness_method: NativelySlowServing) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @in_guaranteed SlowServer) -> Int {
+// CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : @guaranteed $String, [[SELF_ADDR:%.*]] : $*SlowServer):
+// CHECK-NN:   [[SELF:%.*]] = load_borrow [[SELF_ADDR]]
+// CHECK-NN:   [[FUNC:%.*]] = function_ref @$sSo10SlowServerC011doSomethingA0ySiSSYaFTO : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServer) -> Int
+// CHECK-NN:   apply [[FUNC]]([[ACTOR]], [[ARG]], [[SELF]])
+// CHECK-NN:   hop_to_executor [[ACTOR]]
+// CHECK-NN: } // end sil function '$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP011doSomethingA0ySiSSYaFTW'
+
+// protocol witness for NativelySlowServing.findAnswer() in conformance SlowServer
+// CHECK-C-LABEL: sil private [transparent] [thunk] [ossa] @$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP10findAnswerSSyYaKFTW : $@convention(witness_method: NativelySlowServing) @async (@in_guaranteed SlowServer) -> (@owned String, @error any Error) {
+// CHECK-C: bb0([[SELF_ADDR:%.*]] : $*SlowServer):
+// CHECK-C:   [[SELF:%.*]] = load_borrow [[SELF_ADDR]]
+// CHECK-C:   [[FUNC:%.*]] = function_ref @$sSo10SlowServerC10findAnswerSSyYaKFTO : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServer) -> (@owned String, @error any Error)
+// CHECK-C:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK-C:   hop_to_executor [[ACTOR]]
+// CHECK-C:   try_apply [[FUNC]]([[ACTOR]], [[SELF]])
+// CHECK-C: } // end sil function '$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP10findAnswerSSyYaKFTW'
+
+// CHECK-NN-LABEL: sil private [transparent] [thunk] [ossa] @$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP10findAnswerSSyYaKFTW : $@convention(witness_method: NativelySlowServing) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed SlowServer) -> (@owned String, @error any Error) {
+// CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[SELF_ADDR:%.*]] : $*SlowServer):
+// CHECK-NN:   [[SELF:%.*]] = load_borrow [[SELF_ADDR]]
+// CHECK-NN:   [[FUNC:%.*]] = function_ref @$sSo10SlowServerC10findAnswerSSyYaKFTO : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServer) -> (@owned String, @error any Error)
+// CHECK-NN:   try_apply [[FUNC]]([[ACTOR]], [[SELF]])
+//
+// CHECK-NN: bb1(
+// CHECK-NN:    hop_to_executor [[ACTOR]]
+//
+// CHECK-NN: bb2(
+// CHECK-NN:    hop_to_executor [[ACTOR]]
+// CHECK-NN: } // end sil function '$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP10findAnswerSSyYaKFTW'
+
+// protocol witness for NativelySlowServing.serverRestart(_:) in conformance SlowServer
+// CHECK-C-LABEL: sil private [transparent] [thunk] [ossa] @$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP13serverRestartyySSYaFTW : $@convention(witness_method: NativelySlowServing) @async (@guaranteed String, @in_guaranteed SlowServer) -> () {
+// CHECK-C: bb0([[ARG:%.*]] : @guaranteed $String, [[SELF_PTR:%.*]] : $*SlowServer):
+// CHECK-C:   [[SELF:%.*]] = load_borrow [[SELF_PTR]]
+// CHECK-C:   [[FUNC:%.*]] = function_ref @$sSo10SlowServerC13serverRestartyySSYaFTO : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServer) -> ()
+// CHECK-C:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK-C:   hop_to_executor [[ACTOR]]
+// CHECK-C:   apply [[FUNC]]([[ACTOR]], [[ARG]], [[SELF]])
+// CHECK-C: } // end sil function '$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP13serverRestartyySSYaFTW'
+
+// CHECK-NN-LABEL: sil private [transparent] [thunk] [ossa] @$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP13serverRestartyySSYaFTW : $@convention(witness_method: NativelySlowServing) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @in_guaranteed SlowServer) -> () {
+// CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : @guaranteed $String, [[SELF_PTR:%.*]] : $*SlowServer):
+// CHECK-NN:   [[SELF:%.*]] = load_borrow [[SELF_PTR]]
+// CHECK-NN:   [[FUNC:%.*]] = function_ref @$sSo10SlowServerC13serverRestartyySSYaFTO : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServer) -> ()
+// CHECK-NN:   apply [[FUNC]]([[ACTOR]], [[ARG]], [[SELF]])
+// CHECK-NN:   hop_to_executor [[ACTOR]]
+// CHECK-NN: } // end sil function '$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP13serverRestartyySSYaFTW'
+
+// protocol witness for NativelySlowServing.findMultipleAnswers() in conformance SlowServer
+// CHECK-C-LABEL: sil private [transparent] [thunk] [ossa] @$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP19findMultipleAnswersSS_SityYaKFTW : $@convention(witness_method: NativelySlowServing) @async (@in_guaranteed SlowServer) -> (@owned String, Int, @error any Error) {
+// CHECK-C: bb0([[SELF_ADDR:%.*]] : $*SlowServer):
+// CHECK-C:   [[SELF:%.*]] = load_borrow [[SELF_ADDR]]
+// CHECK-C:   [[FUNC:%.*]] = function_ref @$sSo10SlowServerC19findMultipleAnswersSS_SityYaKFTO : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServer) -> (@owned String, Int, @error any Error)
+// CHECK-C:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+// CHECK-C:   hop_to_executor [[ACTOR]]
+// CHECK-C:   try_apply [[FUNC]]([[ACTOR]], [[SELF]])
+// CHECK-C: } // end sil function '$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP19findMultipleAnswersSS_SityYaKFTW'
+
+// CHECK-NN-LABEL: sil private [transparent] [thunk] [ossa] @$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP19findMultipleAnswersSS_SityYaKFTW : $@convention(witness_method: NativelySlowServing) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @in_guaranteed SlowServer) -> (@owned String, Int, @error any Error) {
+// CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[SELF_ADDR:%.*]] : $*SlowServer):
+// CHECK-NN:   [[SELF:%.*]] = load_borrow [[SELF_ADDR]]
+// CHECK-NN:   [[FUNC:%.*]] = function_ref @$sSo10SlowServerC19findMultipleAnswersSS_SityYaKFTO : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServer) -> (@owned String, Int, @error any Error)
+// CHECK-NN:   try_apply [[FUNC]]([[ACTOR]], [[SELF]])
+//
+// CHECK-NN:  bb1(
+// CHECK-NN:   hop_to_executor [[ACTOR]]
+//
+// CHECK-NN:  bb2(
+// CHECK-NN:   hop_to_executor [[ACTOR]]
+// CHECK-NN: } // end sil function '$sSo10SlowServerC21objc_async_from_swift08NativelyA7ServingA2cDP19findMultipleAnswersSS_SityYaKFTW'
+
 class SlowServerlet: SlowServer {
-    // CHECK-LABEL: sil{{.*}}13SlowServerlet{{.*}}011doSomethingE8Nullably{{.*}}
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
+    // Native Function
+    //
+    // CHECK-C-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC011doSomethingE8NullablyySiSSYaF : $@convention(method) @async (@guaranteed String, @guaranteed SlowServerlet) -> Int
+    // CHECK-C-NOT: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>
+    // CHECK-C: [[ACTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-C:   hop_to_executor [[ACTOR]]
+    // CHECK-C:   // end sil function '$s21objc_async_from_swift13SlowServerletC011doSomethingE8NullablyySiSSYaF'
+
+    // CHECK-NN-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC011doSomethingE8NullablyySiSSYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServerlet) -> Int {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift13SlowServerletC011doSomethingE8NullablyySiSSYaF'
+
+    // TODO: We are labeling this as having caller_isolation_inheriting when NN
+    // is enabled... but we do not have an actor parameter. This is incorrect.
+    //
+    // @objc thunk closure
+    //
+    // CHECK-LABEL: sil shared [thunk] [ossa] @$s21objc_async_from_swift13SlowServerletC011doSomethingE8NullablyySiSSYaFyyYacfU_To : $@convention(thin) @Sendable @async (NSString, Optional<@convention(block) @Sendable (Int) -> ()>, SlowServerlet) -> () {
+    // CHECK-NN: [[NONE:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+    // CHECK: [[STR_ARG:%.*]] = begin_borrow {{.*}} : $String
+    // CHECK: [[SELF:%.*]] = begin_borrow {{.*}} : $SlowServerlet
+    // CHECK-C: [[FUNC:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC011doSomethingE8NullablyySiSSYaF : $@convention(method) @async (@guaranteed String, @guaranteed SlowServerlet) -> Int
+    // CHECK-C: apply [[FUNC]]([[STR_ARG]], [[SELF]])
+    // CHECK-NN: [[FUNC:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC011doSomethingE8NullablyySiSSYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServerlet) -> Int
+    // CHECK-NN: apply [[FUNC]]([[NONE]], [[STR_ARG]], [[SELF]])
+    // CHECK: } // end sil function '$s21objc_async_from_swift13SlowServerletC011doSomethingE8NullablyySiSSYaFyyYacfU_To'
     override func doSomethingSlowNullably(_: String) async -> Int {
         return 0
     }
 
-    // CHECK-LABEL: sil{{.*}}13SlowServerlet{{.*}}18findAnswerNullably{{.*}}
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
+    // Native function.
+    //
+    // CHECK-C-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC18findAnswerNullablyyS2SYaF : $@convention(method) @async (@guaranteed String, @guaranteed SlowServerlet) -> @owned String
+    // CHECK-C-NOT: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>
+    // CHECK-C: [[ACTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-C-NEXT: hop_to_executor [[ACTOR]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift13SlowServerletC18findAnswerNullablyyS2SYaF'
+
+    // CHECK-NN-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC18findAnswerNullablyyS2SYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServerlet) -> @owned String {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-NN: hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift13SlowServerletC18findAnswerNullablyyS2SYaF'
+
+    // @objc closure thunk
+    // CHECK-LABEL: sil shared [thunk] [ossa] @$s21objc_async_from_swift13SlowServerletC18findAnswerNullablyyS2SYaFyyYacfU_To : $@convention(thin) @Sendable @async (NSString, Optional<@convention(block) @Sendable (NSString) -> ()>, SlowServerlet) -> () {
+    // CHECK-NN: [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+    // CHECK: [[STR_ARG:%.*]] = begin_borrow {{.*}} : $String
+    // CHECK: [[SELF:%.*]] = begin_borrow {{.*}} : $SlowServerlet
+    // CHECK-C: [[FUNC:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC18findAnswerNullablyyS2SYaF : $@convention(method) @async (@guaranteed String, @guaranteed SlowServerlet) -> @owned String
+    // CHECK-C: apply [[FUNC]]([[STR_ARG]], [[SELF]])
+    // CHECK-NN: [[FUNC:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC18findAnswerNullablyyS2SYaF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServerlet) -> @owned String
+    // CHECK-NN: apply [[FUNC]]([[ACTOR]], [[STR_ARG]], [[SELF]])
+    // CHECK: } // end sil function '$s21objc_async_from_swift13SlowServerletC18findAnswerNullablyyS2SYaFyyYacfU_To'
     override func findAnswerNullably(_ x: String) async -> String {
         return x
     }
 
-    // CHECK-LABEL: sil{{.*}}13SlowServerlet{{.*}}28doSomethingDangerousNullably{{.*}} :
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
+    // Native
+    //
+    // CHECK-C-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC28doSomethingDangerousNullablyyS2SYaKF : $@convention(method) @async (@guaranteed String, @guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-C-NOT: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C: [[ACTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-C-NEXT: hop_to_executor [[ACTOR]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift13SlowServerletC28doSomethingDangerousNullablyyS2SYaKF'
+
+    // CHECK-NN-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC28doSomethingDangerousNullablyyS2SYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServerlet) -> (@owned String, @error any Error) {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-NN: hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift13SlowServerletC28doSomethingDangerousNullablyyS2SYaKF'
+
+    // @objc thunk closure
+    //
+    // CHECK-LABEL: sil shared [thunk] [ossa] @$s21objc_async_from_swift13SlowServerletC28doSomethingDangerousNullablyyS2SYaKFyyYacfU_To : $@convention(thin) @Sendable @async (NSString, Optional<@convention(block) @Sendable (Optional<NSString>, Optional<NSError>) -> ()>, SlowServerlet) -> () {
+    // CHECK-NN: [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+    // CHECK: [[STR_ARG:%.*]] = begin_borrow {{.*}} : $String
+    // CHECK: [[SELF:%.*]] = begin_borrow {{.*}} : $SlowServerlet
+    // CHECK-C: [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC28doSomethingDangerousNullablyyS2SYaKF : $@convention(method) @async (@guaranteed String, @guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-C: apply [[NATIVE]]([[STR_ARG]], [[SELF]])
+    // CHECK-NN: [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC28doSomethingDangerousNullablyyS2SYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-NN: apply [[NATIVE]]([[ACTOR]], [[STR_ARG]], [[SELF]])
+    // CHECK: } // end sil function '$s21objc_async_from_swift13SlowServerletC28doSomethingDangerousNullablyyS2SYaKFyyYacfU_To'
     override func doSomethingDangerousNullably(_ x: String) async throws -> String {
         return x
     }
 
-    // CHECK-LABEL: sil{{.*}}13SlowServerlet{{.*}}30doSomethingUnspecifiedNullably{{.*}} :
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
+    // Native
+    //
+    // CHECK-C-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC30doSomethingUnspecifiedNullablySSyYaKF : $@convention(method) @async (@guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-C-NOT: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C: [[ACTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-C-NEXT: hop_to_executor [[ACTOR]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift13SlowServerletC30doSomethingUnspecifiedNullablySSyYaKF'
+
+    // CHECK-NN-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC30doSomethingUnspecifiedNullablySSyYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServerlet) -> (@owned String, @error any Error) {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift13SlowServerletC30doSomethingUnspecifiedNullablySSyYaKF'
+
+    // @objc closure thunk
+    // CHECK-LABEL: sil shared [thunk] [ossa] @$s21objc_async_from_swift13SlowServerletC30doSomethingUnspecifiedNullablySSyYaKFyyYacfU_To : $@convention(thin) @Sendable @async (Optional<@convention(block) @Sendable (Optional<NSString>, Optional<NSError>) -> ()>, SlowServerlet) -> () {
+    // CHECK-NN: [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+    // CHECK: [[SELF:%.*]] = begin_borrow {{.*}} : $SlowServerlet
+    // CHECK-C: [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC30doSomethingUnspecifiedNullablySSyYaKF : $@convention(method) @async (@guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-C: try_apply [[NATIVE]]([[SELF]])
+    // CHECK-NN: [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC30doSomethingUnspecifiedNullablySSyYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-NN: try_apply [[NATIVE]]([[ACTOR]], [[SELF]])
+    // CHECK: } // end sil function '$s21objc_async_from_swift13SlowServerletC30doSomethingUnspecifiedNullablySSyYaKFyyYacfU_To'
     override func doSomethingUnspecifiedNullably() async throws -> String {
       fatalError()
     }
 
-    // CHECK-LABEL: sil{{.*}}13SlowServerlet{{.*}}17doSomethingFlaggy{{.*}} :
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
-    // CHECK-LABEL: sil private{{.*}}13SlowServerlet{{.*}}17doSomethingFlaggy{{.*}}To :
-    // CHECK:         try_apply{{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
-    // CHECK:       [[NORMAL_BB]]({{.*}}):
-    // CHECK:         integer_literal {{.*}}0 
-    // CHECK:       [[ERROR_BB]]({{.*}}):
-    // CHECK:         integer_literal {{.*}}1 
+    // Native
+    //
+    // CHECK-C-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC17doSomethingFlaggySSyYaKF : $@convention(method) @async (@guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-C-NOT: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C: [[ACTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-C-NEXT: hop_to_executor [[ACTOR]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift13SlowServerletC17doSomethingFlaggySSyYaKF'
+
+    // CHECK-NN-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC17doSomethingFlaggySSyYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServerlet) -> (@owned String, @error any Error) {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift13SlowServerletC17doSomethingFlaggySSyYaKF'
+
+    // @objc thunk closure
+    // CHECK-LABEL: sil shared [thunk] [ossa] @$s21objc_async_from_swift13SlowServerletC17doSomethingFlaggySSyYaKFyyYacfU_To : $@convention(thin) @Sendable @async (@convention(block) @Sendable ({{.*}}, Optional<NSString>, Optional<NSError>) -> (), SlowServerlet) -> () {
+    // CHECK-NN: [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+    // CHECK:    [[SELF:%.*]] = begin_borrow {{.*}} : $SlowServerlet
+    // CHECK-C:  [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC17doSomethingFlaggySSyYaKF : $@convention(method) @async (@guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-C:  try_apply [[NATIVE]]([[SELF]]) : {{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
+    // CHECK-NN: [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC17doSomethingFlaggySSyYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-NN: try_apply [[NATIVE]]([[ACTOR]], [[SELF]]) : {{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
+    //
+    // CHECK: [[NORMAL_BB]]({{.*}}):
+    // CHECK:    integer_literal {{.*}}0
+    //
+    // CHECK: [[ERROR_BB]]({{.*}}):
+    // CHECK:    integer_literal {{.*}}1
+    // CHECK: } // end sil function '$s21objc_async_from_swift13SlowServerletC17doSomethingFlaggySSyYaKFyyYacfU_To'
     override func doSomethingFlaggy() async throws -> String {
         return ""
     }
 
-    // CHECK-LABEL: sil{{.*}}13SlowServerlet{{.*}}21doSomethingZeroFlaggy{{.*}} :
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
-    // CHECK-LABEL: sil private{{.*}}13SlowServerlet{{.*}}21doSomethingZeroFlaggy{{.*}}To :
-    // CHECK:         try_apply{{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
-    // CHECK:       [[NORMAL_BB]]({{.*}}):
-    // CHECK:         integer_literal {{.*}}1 
-    // CHECK:       [[ERROR_BB]]({{.*}}):
-    // CHECK:         integer_literal {{.*}}0 
+    // Native
+    //
+    // CHECK-C-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC21doSomethingZeroFlaggySSyYaKF : $@convention(method) @async (@guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-C-NOT: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C: [[ACTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-C-NEXT: hop_to_executor [[ACTOR]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift13SlowServerletC21doSomethingZeroFlaggySSyYaKF'
+    //
+    // CHECK-NN-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC21doSomethingZeroFlaggySSyYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServerlet) -> (@owned String, @error any Error) {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-NN:  hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift13SlowServerletC21doSomethingZeroFlaggySSyYaKF'
+    //
+    // @objc thunk closure
+    // CHECK-LABEL: sil shared [thunk] [ossa] @$s21objc_async_from_swift13SlowServerletC21doSomethingZeroFlaggySSyYaKFyyYacfU_To : $@convention(thin) @Sendable @async (@convention(block) @Sendable (Optional<NSString>, {{.*}}, Optional<NSError>) -> (), SlowServerlet) -> () {
+    // CHECK-NN:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+    // CHECK:      [[SELF:%.*]] = begin_borrow {{.*}} : $SlowServerlet
+    // CHECK-C:    [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC21doSomethingZeroFlaggySSyYaKF : $@convention(method) @async (@guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-C:    try_apply [[NATIVE]]([[SELF]]) : {{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
+    // CHECK-NN:   [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC21doSomethingZeroFlaggySSyYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServerlet) -> (@owned String, @error any Error)
+    // CHECK-NN:   try_apply [[NATIVE]]([[ACTOR]], [[SELF]]) : {{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
+    //
+    // CHECK:  [[NORMAL_BB]]({{.*}}):
+    // CHECK:      integer_literal {{.*}}1
+    //
+    // CHECK:  [[ERROR_BB]]({{.*}}):
+    // CHECK:      integer_literal {{.*}}0
     override func doSomethingZeroFlaggy() async throws -> String {
         return ""
     }
 
-    // CHECK-LABEL: sil{{.*}}13SlowServerlet{{.*}}28doSomethingMultiResultFlaggy{{.*}} :
-    // CHECK:         [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none
-    // CHECK:         hop_to_executor [[GENERIC_EXECUTOR]] :
-    // CHECK-LABEL: sil private{{.*}}13SlowServerlet{{.*}}28doSomethingMultiResultFlaggy{{.*}}To :
-    // CHECK:         try_apply{{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
-    // CHECK:       [[NORMAL_BB]]({{.*}}):
-    // CHECK:         integer_literal {{.*}}1 
-    // CHECK:       [[ERROR_BB]]({{.*}}):
-    // CHECK:         integer_literal {{.*}}0 
+    // Native
+    //
+    // CHECK-C-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC28doSomethingMultiResultFlaggySS_SStyYaKF : $@convention(method) @async (@guaranteed SlowServerlet) -> (@owned String, @owned String, @error any Error)
+    // CHECK-C-NOT: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-C: [[ACTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-C-NEXT: hop_to_executor [[ACTOR]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift13SlowServerletC28doSomethingMultiResultFlaggySS_SStyYaKF'
+    //
+    // CHECK-NN-LABEL: sil hidden [ossa] @$s21objc_async_from_swift13SlowServerletC28doSomethingMultiResultFlaggySS_SStyYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServerlet) -> (@owned String, @owned String, @error any Error) {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>,
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift13SlowServerletC28doSomethingMultiResultFlaggySS_SStyYaKF'
+    //
+    // CHECK-LABEL: sil shared [thunk] [ossa] @$s21objc_async_from_swift13SlowServerletC28doSomethingMultiResultFlaggySS_SStyYaKFyyYacfU_To : $@convention(thin) @Sendable @async (@convention(block) @Sendable ({{.*}}, Optional<NSString>, Optional<NSError>, Optional<NSString>) -> (), SlowServerlet) -> () {
+    // CHECK-NN: [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+    // CHECK:    [[SELF:%.*]] = begin_borrow {{.*}} : $SlowServerlet
+    // CHECK-C:  [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC28doSomethingMultiResultFlaggySS_SStyYaKF : $@convention(method) @async (@guaranteed SlowServerlet) -> (@owned String, @owned String, @error any Error)
+    // CHECK-C:  try_apply [[NATIVE]]([[SELF]]) : {{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
+    // CHECK-NN: [[NATIVE:%.*]] = function_ref @$s21objc_async_from_swift13SlowServerletC28doSomethingMultiResultFlaggySS_SStyYaKF : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed SlowServerlet) -> (@owned String, @owned String, @error any Error)
+    // CHECK-NN: try_apply [[NATIVE]]([[ACTOR]], [[SELF]]) : {{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
+    //
+    // CHECK: [[NORMAL_BB]]({{.*}}):
+    // CHECK:   integer_literal {{.*}}1
+    //
+    // CHECK: [[ERROR_BB]]({{.*}}):
+    // CHECK:   integer_literal {{.*}}0
+    // CHECK: } // end sil function '$s21objc_async_from_swift13SlowServerletC28doSomethingMultiResultFlaggySS_SStyYaKFyyYacfU_To'
     override func doSomethingMultiResultFlaggy() async throws -> (String, String) {
         return ("", "")
     }
@@ -221,3 +455,265 @@ actor Dril: NSObject {
         return true
     }
 }
+
+// Check that we do not crash here and emit the autoclosures correctly
+func testAutoclosureInStaticMethod() {
+  final class TestKlass {
+    // Default argument for method.
+    //
+    // CHECK-C-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_ : $@convention(thin) () -> @owned @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error) {
+    // CHECK-NN-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_ : $@convention(thin) () -> @owned @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error) {
+    //
+    // Get standard.
+    // CHECK: [[METATYPE:%.*]] = metatype $@objc_metatype SlowServer.Type
+    // CHECK: [[GET_STANDARD_FUNC:%.*]] = objc_method [[METATYPE]] : $@objc_metatype SlowServer.Type, #SlowServer.standard!getter.foreign : (SlowServer.Type) -> () -> SlowServer, $@convention(objc_method) (@objc_metatype SlowServer.Type) -> @autoreleased SlowServer
+    // CHECK: [[STANDARD:%.*]] = apply [[GET_STANDARD_FUNC]]([[METATYPE]])
+    //
+    // Then grab value.
+    // CHECK-C: [[GET_VALUE:%.*]] = function_ref @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_ : $@convention(thin) (@guaranteed SlowServer) -> @owned @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error)
+    // CHECK-NN: [[GET_VALUE:%.*]] = function_ref @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_ : $@convention(thin) (@guaranteed SlowServer) -> @owned @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error)
+    // CHECK: [[RESULT:%.*]] = apply [[GET_VALUE]]([[STANDARD]])
+    //
+    // Then we need to thunk to eliminate the implicit leading parameter. We use
+    // the thunk that passes in .none so this acts as a concurrent function.
+    //
+    // CHECK-C: [[THUNK_FN:%.*]] = function_ref @$sScA_pSgS2Ss5Error_pIegHgILgozo_S2SsAB_pIegHgozo_TR : $@convention(thin) @async (@guaranteed String, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error)) -> (@owned String, @error any Error)
+    // CHECK-C: [[THUNKED:%.*]] = partial_apply [callee_guaranteed] [[THUNK_FN]]([[RESULT]])
+    // CHECK-C: return [[THUNKED]]
+    // CHECK-NN: return [[RESULT]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_'
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_'
+
+    // This is the first implicit closure. We close over self here.
+    //
+    // CHECK-C-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_ : $@convention(thin) (@guaranteed SlowServer) -> @owned @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error) {
+    // CHECK: bb0([[SELF:%.*]] :
+    //
+    // Close over self and return it.
+    // CHECK-C:   [[SECOND_CLOSURE:%.*]] = function_ref @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_S2SYaKYCcfu0_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServer) -> (@owned String, @error any Error)
+    // CHECK-NN:  [[SECOND_CLOSURE:%.*]] = function_ref @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_S2SYaKYCcfu0_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServer) -> (@owned String, @error any Error)
+    // CHECK:   [[SELF_COPY:%.*]] = copy_value [[SELF]]
+    // CHECK:   [[CLOSE_OVER_SELF:%.*]] = partial_apply [callee_guaranteed] [[SECOND_CLOSURE]]([[SELF_COPY]])
+    // CHECK:   return [[CLOSE_OVER_SELF]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_'
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_' 
+
+    // The second closure. In this function we actually perform the objective-c call.
+    // CHECK-C-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_S2SYaKYCcfu0_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServer) -> (@owned String, @error any Error) {
+    // CHECK-NN-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_S2SYaKYCcfu0_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed SlowServer) -> (@owned String, @error any Error) {
+    // CHECK: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : @guaranteed $String, [[CAPTURE:%.*]] : @closureCapture @guaranteed $SlowServer):
+    //
+    // Hop to the actor
+    // CHECK:   hop_to_executor [[ACTOR]]
+    //
+    // Declare result
+    // CHECK:   [[RESULT:%.*]] = alloc_stack $String
+    //
+    // Bridge string arg.
+    // CHECK:   [[ARG_C:%.*]] = copy_value [[ARG]]
+    // CHECK:   [[BRIDGE_FN:%.*]] = function_ref @$sSS10FoundationE19_bridgeToObjectiveCSo8NSStringCyF : $@convention(method) (@guaranteed String) -> @owned NSString
+    // CHECK:   [[ARG_C_B:%.*]] = begin_borrow [[ARG_C]]
+    // CHECK:   [[NS_STRING:%.*]] = apply [[BRIDGE_FN]]([[ARG_C_B]])
+    //
+    // ObjC Method
+    // CHECK:   [[OBJC_METHOD:%.*]] = objc_method [[CAPTURE]]
+    //
+    // Prepare the continuation.
+    // CHECK:   [[RAW_UNSAFE_CONT:%.*]] = get_async_continuation_addr [throws] String, [[RESULT]]
+    // CHECK:   [[UNSAFE_CONT:%.*]] = struct $UnsafeContinuation<String, any Error> ([[RAW_UNSAFE_CONT]] :
+    // CHECK:   [[BLOCK_STORAGE:%.*]] = alloc_stack $@block_storage Any
+    // CHECK:   [[PROJ_BLOCK_STORAGE:%.*]] = project_block_storage [[BLOCK_STORAGE]]
+    // CHECK:   [[INIT_PROJ_BLOCK_STORAGE:%.*]] = init_existential_addr [[PROJ_BLOCK_STORAGE]]
+    // CHECK:   store [[UNSAFE_CONT]] to [trivial] [[INIT_PROJ_BLOCK_STORAGE]]
+    // CHECK:   merge_isolation_region [[BLOCK_STORAGE]] : $*@block_storage Any, [[RESULT]]
+    // CHECK:   [[OBJC_COMPLETION_HANDLER_IMPL:%.*]] = function_ref @$sSo8NSStringCSgSo7NSErrorCSgIeyBhyy_SSTz_ : $@convention(c) @Sendable (@inout_aliasable @block_storage Any, Optional<NSString>, Optional<NSError>) -> ()
+    // CHECK:   [[BLOCK:%.*]] = init_block_storage_header [[BLOCK_STORAGE]] : $*@block_storage Any, invoke [[OBJC_COMPLETION_HANDLER_IMPL]]
+    // CHECK:   merge_isolation_region [[CAPTURE]] : $SlowServer, [[BLOCK_STORAGE]]
+    // CHECK:   apply [[OBJC_METHOD]]([[NS_STRING]], [[BLOCK]], [[CAPTURE]])
+    // CHECK:   await_async_continuation [[RAW_UNSAFE_CONT]] : $Builtin.RawUnsafeContinuation, resume [[RESUME_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
+    //
+    // CHECK: [[RESUME_BB]]:
+    // CHECK:   hop_to_executor [[ACTOR]]
+    // CHECK:   [[LOADED_RESULT:%.*]] = load [take] [[RESULT]]
+    // CHECK:   return [[LOADED_RESULT]]
+    //
+    // CHECK: [[ERROR_BB]]([[ERROR:%.*]] :
+    // CHECK:   hop_to_executor [[ACTOR]]
+    // CHECK:   throw [[ERROR]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_S2SYaKYCcfu0_'
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKYCcSo10SlowServerCcfu_S2SYaKYCcfu0_'
+
+      // thunk for @escaping @callee_guaranteed @async (@guaranteed Actor?, @guaranteed String) -> (@owned String, @error @owned Error)
+
+    // CHECK-C-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sScA_pSgS2Ss5Error_pIegHgILgozo_S2SsAB_pIegHgozo_TR : $@convention(thin) @async (@guaranteed String, @guaranteed @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error)) -> (@owned String, @error any Error) {
+    // CHECK-C: bb0([[ARG:%.*]] : @guaranteed $String, [[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error)):
+    // CHECK-C:   [[ACTOR:%.*]] = enum $Optional<any Actor>, #Optional.none!enumelt
+    // CHECK-C:   hop_to_executor [[ACTOR]]
+    // CHECK-C:   try_apply [[FUNC]]([[ACTOR]], [[ARG]])
+    // CHECK-C: } // end sil function '$sScA_pSgS2Ss5Error_pIegHgILgozo_S2SsAB_pIegHgozo_TR'
+
+    // Actual static method
+    //
+    // We do not actually care about FileChecking this... we just need to
+    // FileCheck the hop_to_executor to show to FileCheck that we expect these
+    // hop_to_executor lines to occur in the function since we reject
+    // non-explicitly specified hop_to_executor lines.
+    //
+    // CHECK-C-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZ : $@convention(method) @async (@guaranteed String, @guaranteed @noescape @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error), @thick TestKlass.Type) -> @owned Optional<String> {
+    // CHECK-C: bb0([[STRING:%.*]] : @guaranteed $String, [[COMPLETION:%.*]] : @guaranteed $@noescape @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error), [[METATYPE:%.*]] : $@thick TestKlass.Type)
+    // CHECK-C:   [[EXEC_NONE:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-C:   hop_to_executor [[EXEC_NONE]]
+    // CHECK-C:   hop_to_executor [[EXEC_NONE]]
+    // CHECK-C:   hop_to_executor [[EXEC_NONE]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZ'
+
+    // CHECK-NN-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZ : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error), @thick TestKlass.Type) -> @owned Optional<String> {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[STRING:%.*]] : @guaranteed $String, [[COMPLETION:%.*]] : @guaranteed $@noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error), %3 : $@thick TestKlass.Type):
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C8getValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZ'
+
+    static func getValue(id: String,
+                         valueForKey: (_ identifier: String) async throws -> String = SlowServer.standard.value(withKey:)) async -> String? {
+      let result: String
+      do {
+        result = try await valueForKey(id)
+      } catch {
+        return nil
+      }
+      return result
+    }
+
+    // Default argument for method.
+    //
+    // CHECK-C-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_ : $@convention(thin) () -> @owned @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error) {
+    // CHECK-NN-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_ : $@convention(thin) () -> @owned @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error) {
+    //
+    // Get standard.
+    // CHECK: [[METATYPE:%.*]] = metatype $@objc_metatype SlowServer.Type
+    // CHECK: [[GET_STANDARD_FUNC:%.*]] = objc_method [[METATYPE]] : $@objc_metatype SlowServer.Type, #SlowServer.standard!getter.foreign : (SlowServer.Type) -> () -> SlowServer, $@convention(objc_method) (@objc_metatype SlowServer.Type) -> @autoreleased SlowServer
+    // CHECK: [[STANDARD:%.*]] = apply [[GET_STANDARD_FUNC]]([[METATYPE]])
+    //
+    // Then grab value.
+    // CHECK-C: [[GET_VALUE:%.*]] = function_ref @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_ : $@convention(thin) (@guaranteed SlowServer) -> @owned @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error)
+    // CHECK-NN: [[GET_VALUE:%.*]] = function_ref @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_ : $@convention(thin) (@guaranteed SlowServer) -> @owned @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error)
+    // CHECK: [[RESULT:%.*]] = apply [[GET_VALUE]]([[STANDARD]])
+    //
+    // CHECK-NN: [[THUNK:%.*]] = function_ref @$sS2Ss5Error_pIegHgozo_ScA_pSgS2SsAA_pIegHgILgozo_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error)) -> (@owned String, @error any Error)
+    // CHECK-NN: [[THUNKED_RESULT:%.*]] = partial_apply [callee_guaranteed] [[THUNK]]([[RESULT]])
+    // CHECK-C: return [[RESULT]]
+    // CHECK-NN: return [[THUNKED_RESULT]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_'
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_'
+
+    // This is the first implicit closure. We close over self here.
+    //
+    // CHECK-C-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_ : $@convention(thin) (@guaranteed SlowServer) -> @owned @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error) {
+    // CHECK-NN-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_ : $@convention(thin) (@guaranteed SlowServer) -> @owned @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error) {
+    // CHECK: bb0([[SELF:%.*]] :
+    //
+    // Close over self and return it.
+    // CHECK-C:  [[SECOND_CLOSURE:%.*]] = function_ref @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_S2SYaKScMYccfu0_ : $@convention(thin) @async (@guaranteed String, @guaranteed SlowServer) -> (@owned String, @error any Error)
+    // CHECK-NN: [[SECOND_CLOSURE:%.*]] = function_ref @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_S2SYaKScMYccfu0_ : $@convention(thin) @async (@guaranteed String, @guaranteed SlowServer) -> (@owned String, @error any Error)
+    // CHECK:   [[SELF_COPY:%.*]] = copy_value [[SELF]]
+    // CHECK:   [[CLOSE_OVER_SELF:%.*]] = partial_apply [callee_guaranteed] [[SECOND_CLOSURE]]([[SELF_COPY]])
+    // CHECK:   return [[CLOSE_OVER_SELF]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_'
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_'
+
+    // The second closure. In this function we actually perform the objective-c call.
+    //
+    // It is main actor isolated.
+    //
+    // CHECK-C-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_S2SYaKScMYccfu0_ : $@convention(thin) @async (@guaranteed String, @guaranteed SlowServer) -> (@owned String, @error any Error) {
+    // CHECK-NN-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_S2SYaKScMYccfu0_ : $@convention(thin) @async (@guaranteed String, @guaranteed SlowServer) -> (@owned String, @error any Error) {
+    // CHECK: bb0([[ARG:%.*]] : @guaranteed $String, [[CAPTURE:%.*]] : @closureCapture @guaranteed $SlowServer):
+    //
+    // CHECK:   [[ACTOR:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+    //
+    // Hop to the actor
+    // CHECK:   [[ACTOR_B:%.*]] = begin_borrow [[ACTOR]]
+    // CHECK:   hop_to_executor [[ACTOR_B]]
+    //
+    // Declare result
+    // CHECK:   [[RESULT:%.*]] = alloc_stack $String
+    //
+    // Bridge string arg.
+    // CHECK:   [[ARG_C:%.*]] = copy_value [[ARG]]
+    // CHECK:   [[BRIDGE_FN:%.*]] = function_ref @$sSS10FoundationE19_bridgeToObjectiveCSo8NSStringCyF : $@convention(method) (@guaranteed String) -> @owned NSString
+    // CHECK:   [[ARG_C_B:%.*]] = begin_borrow [[ARG_C]]
+    // CHECK:   [[NS_STRING:%.*]] = apply [[BRIDGE_FN]]([[ARG_C_B]])
+    //
+    // ObjC Method
+    // CHECK:   [[OBJC_METHOD:%.*]] = objc_method [[CAPTURE]]
+    //
+    // Prepare the continuation.
+    // CHECK:   [[RAW_UNSAFE_CONT:%.*]] = get_async_continuation_addr [throws] String, [[RESULT]]
+    // CHECK:   [[UNSAFE_CONT:%.*]] = struct $UnsafeContinuation<String, any Error> ([[RAW_UNSAFE_CONT]] :
+    // CHECK:   [[BLOCK_STORAGE:%.*]] = alloc_stack $@block_storage Any
+    // CHECK:   [[PROJ_BLOCK_STORAGE:%.*]] = project_block_storage [[BLOCK_STORAGE]]
+    // CHECK:   [[INIT_PROJ_BLOCK_STORAGE:%.*]] = init_existential_addr [[PROJ_BLOCK_STORAGE]]
+    // CHECK:   store [[UNSAFE_CONT]] to [trivial] [[INIT_PROJ_BLOCK_STORAGE]]
+    // CHECK:   merge_isolation_region [[BLOCK_STORAGE]] : $*@block_storage Any, [[RESULT]]
+    // CHECK:   [[OBJC_COMPLETION_HANDLER_IMPL:%.*]] = function_ref @$sSo8NSStringCSgSo7NSErrorCSgIeyByy_SSTz_ : $@convention(c) (@inout_aliasable @block_storage Any, Optional<NSString>, Optional<NSError>) -> ()
+    // CHECK:   [[BLOCK:%.*]] = init_block_storage_header [[BLOCK_STORAGE]] : $*@block_storage Any, invoke [[OBJC_COMPLETION_HANDLER_IMPL]]
+    // CHECK:   apply [[OBJC_METHOD]]([[NS_STRING]], [[BLOCK]], [[CAPTURE]])
+    // CHECK:   await_async_continuation [[RAW_UNSAFE_CONT]] : $Builtin.RawUnsafeContinuation, resume [[RESUME_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
+    //
+    // CHECK: [[RESUME_BB]]:
+    // CHECK:   hop_to_executor [[ACTOR_B]]
+    // CHECK:   [[LOADED_RESULT:%.*]] = load [take] [[RESULT]]
+    // CHECK:   return [[LOADED_RESULT]]
+    //
+    // CHECK: [[ERROR_BB]]([[ERROR:%.*]] :
+    // CHECK:   hop_to_executor [[ACTOR_B]]
+    // CHECK:   throw [[ERROR]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_S2SYaKScMYccfu0_'
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZfA0_S2SYaKScMYccSo10SlowServerCcfu_S2SYaKScMYccfu0_'
+
+    // NOTE: This is earlier in the file when not compiling with
+    // nonisolated(nonsending) by default just due to the way the compiler emits
+    // thunks at different times due to different usages.
+    //
+    // CHECK-NN-LABEL: sil shared [transparent] [serialized] [reabstraction_thunk] [ossa] @$sS2Ss5Error_pIegHgozo_ScA_pSgS2SsAA_pIegHgILgozo_TR : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error)) -> (@owned String, @error any Error) {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[ARG:%.*]] : @guaranteed $String, [[FUNC:%.*]] : @guaranteed $@async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error)):
+    // CHECK-NN:   try_apply [[FUNC]]([[ARG]])
+    //
+    // CHECK-NN: bb1(
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    //
+    // CHECK-NN: bb2(
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$sS2Ss5Error_pIegHgozo_ScA_pSgS2SsAA_pIegHgILgozo_TR'
+
+    // Actual static method
+    //
+    // This is not main actor isolated
+    //
+    // CHECK-C-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZ : $@convention(method) @async (@guaranteed String, @guaranteed @noescape @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error), @thick TestKlass.Type) -> @owned Optional<String> {
+    // CHECK-C: bb0([[STRING:%.*]] : @guaranteed $String, [[COMPLETION:%.*]] : @guaranteed $@noescape @async @callee_guaranteed (@guaranteed String) -> (@owned String, @error any Error), [[METATYPE:%.*]] : $@thick TestKlass.Type)
+    // CHECK-C:   [[EXEC_NONE:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-C:   hop_to_executor [[EXEC_NONE]]
+    // CHECK-C:   hop_to_executor [[EXEC_NONE]]
+    // CHECK-C:   hop_to_executor [[EXEC_NONE]]
+    // CHECK-C: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKXEtYaFZ'
+    //
+    // CHECK-NN-LABEL: sil private [ossa] @$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZ : $@convention(method) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String, @guaranteed @noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error), @thick TestKlass.Type) -> @owned Optional<String> {
+    // CHECK-NN: bb0([[ACTOR:%.*]] : @guaranteed $Optional<any Actor>, [[STRING:%.*]] : @guaranteed $String, [[COMPLETION:%.*]] : @guaranteed $@noescape @async @callee_guaranteed (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, @guaranteed String) -> (@owned String, @error any Error), %3 : $@thick TestKlass.Type)
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN:   hop_to_executor [[ACTOR]]
+    // CHECK-NN: } // end sil function '$s21objc_async_from_swift29testAutoclosureInStaticMethodyyF9TestKlassL_C17getMainActorValue2id11valueForKeySSSgSS_S2SYaKYCXEtYaFZ'
+    static func getMainActorValue(id: String,
+                                  valueForKey: (_ identifier: String) async throws -> String = SlowServer.standard.mainActorValue(withKey:)) async -> String? {
+      let result: String
+      do {
+        result = try await valueForKey(id)
+      } catch {
+        return nil
+      }
+      return result
+    }
+  }
+}
diff --git a/test/SILGen/objc_async_sendable_completion_handlers.swift b/test/SILGen/objc_async_sendable_completion_handlers.swift
new file mode 100644
index 0000000000000..fa9d5a15f2c4a
--- /dev/null
+++ b/test/SILGen/objc_async_sendable_completion_handlers.swift
@@ -0,0 +1,37 @@
+// RUN: %empty-directory(%t/src)
+// RUN: split-file %s %t/src
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sil %t/src/main.swift \
+// RUN:   -import-objc-header %t/src/Test.h \
+// RUN:   -swift-version 6 \
+// RUN:   -module-name main -I %t -verify | %FileCheck %t/src/main.swift
+
+// REQUIRES: objc_interop
+
+// rdar://154695053
+
+//--- Test.h
+
+@import Foundation;
+
+@interface Test <NSObject>
++(void) compute: (void (^)(void)) completion;
+@end
+
+//--- main.swift
+
+func test(v: Test.Type) async {
+  _ = await v.compute()
+}
+
+// CHECK-LABEL: sil hidden @$s4main4test1vySo4TestCm_tYaF : $@convention(thin) @async (@thick Test.Type) -> ()
+// CHECK: [[TEST_TYPE:%.*]] = thick_to_objc_metatype %0 to $@objc_metatype Test.Type
+// CHECK: [[METHOD:%.*]] = objc_method %5, #Test.compute!foreign : (Test.Type) -> () async -> (), $@convention(objc_method) (Optional<@convention(block) @Sendable () -> ()>, @objc_metatype Test.Type) -> ()
+// CHECK: [[BLOCK:%.*]] = alloc_stack $@block_storage Any
+// CHECK: [[COMPLETION_HANDLER:%.*]] = function_ref @$sIeyBh_ytTz_ : $@convention(c) @Sendable (@inout_aliasable @block_storage Any) -> ()
+// CHECK: [[HEADER:%.*]] = init_block_storage_header [[BLOCK]], invoke [[COMPLETION_HANDLER]]
+// CHECK: [[OPTIONAL_HEADER:%.*]] = enum $Optional<@convention(block) @Sendable () -> ()>, #Optional.some!enumelt, [[HEADER]]
+// CHECK: {{.*}} = apply [[METHOD]]([[OPTIONAL_HEADER]], [[TEST_TYPE]])
+// CHECK: } // end sil function '$s4main4test1vySo4TestCm_tYaF'
+
+// CHECK-LABEL: sil shared [transparent] [thunk] @$sIeyBh_ytTz_ : $@convention(c) @Sendable (@inout_aliasable @block_storage Any) -> ()
diff --git a/test/SILGen/objc_bridging.swift b/test/SILGen/objc_bridging.swift
index ec1e5a6bc9da6..79605f7664880 100644
--- a/test/SILGen/objc_bridging.swift
+++ b/test/SILGen/objc_bridging.swift
@@ -630,7 +630,7 @@ func castToCFunction(ptr: UnsafeRawPointer) {
   // CHECK: store %0 to [trivial] [[IN]] : $*UnsafeRawPointer
   // CHECK: [[META:%.*]] = metatype $@thick (@convention(c) (Optional<AnyObject>) -> ()).Type
   // CHECK: [[CASTFN:%.*]] = function_ref @$ss13unsafeBitCast_2toq_x_q_mtr0_lF
-  // CHECK: apply [[CASTFN]]<UnsafeRawPointer, @convention(c) (AnyObject?) -> ()>([[OUT]], [[IN]], [[META]]) : $@convention(thin) <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @thick τ_0_1.Type) -> @out τ_0_1
+  // CHECK: apply [[CASTFN]]<UnsafeRawPointer, @convention(c) (Optional<AnyObject>) -> ()>([[OUT]], [[IN]], [[META]]) : $@convention(thin) <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @thick τ_0_1.Type) -> @out τ_0_1
   // CHECK: [[RESULT:%.*]] = load [trivial] [[OUT]] : $*@convention(c) (Optional<AnyObject>) -> ()
   typealias Fn = @convention(c) (AnyObject?) -> Void
   unsafeBitCast(ptr, to: Fn.self)(nil)
diff --git a/test/SILGen/objc_properties.swift b/test/SILGen/objc_properties.swift
index 09ef6d6a7fe27..f3c3ae8ab8f58 100644
--- a/test/SILGen/objc_properties.swift
+++ b/test/SILGen/objc_properties.swift
@@ -290,10 +290,10 @@ class SomeWrapperTests {
 // CHECK-LABEL: sil hidden [ossa] @$s15objc_properties16SomeWrapperTestsCyACSScfc : $@convention(method) (@owned String, @owned SomeWrapperTests) -> @owned SomeWrapperTests {
 // CHECK:  [[M:%.*]] = function_ref @$s15objc_properties16SomeWrapperTestsC04someD0SivsTD
 // CHECK:  [[C:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[M]]({{.*}})
-// CHECK: assign_by_wrapper {{%.*}}: $Int to {{%.*}} : $*SomeWrapper, init {{.*}} : $@callee_guaranteed (Int) -> SomeWrapper, set [[C]] : $@noescape @callee_guaranteed (Int) -> ()
+// CHECK: assign_or_init #SomeWrapperTests.someWrapper, self {{%.*}} : $SomeWrapperTests, value {{%.*}} : $Int, init {{%.*}} : $@callee_guaranteed (Int) -> @out SomeWrapper, set [[C]] : $@noescape @callee_guaranteed (Int) -> ()
 // CHECK: [[M:%.*]] = function_ref @$s15objc_properties16SomeWrapperTestsC1sSSSgvsTD
 // CHECK: [[C:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[M]](
-// CHECK:  assign_by_wrapper {{.*}} : $Optional<String> to {{.*}} : $*W<Optional<String>>, init {{.*}} : $@callee_guaranteed (@owned Optional<String>) -> @owned W<Optional<String>>, set [[C]] : $@noescape @callee_guaranteed (@owned Optional<String>) -> ()
+// CHECK: assign_or_init #SomeWrapperTests.s, self {{.*}} : $SomeWrapperTests, value {{.*}} : $Optional<String>, init {{.*}} : $@callee_guaranteed (@owned Optional<String>) -> @out W<Optional<String>>, set [[C]] : $@noescape @callee_guaranteed (@owned Optional<String>) -> ()
   init(_ s: String) {
     someWrapper = 1000
     self.s = s
diff --git a/test/SILGen/opaque_result_type_nested_optional.swift b/test/SILGen/opaque_result_type_nested_optional.swift
index 0ec92953a6cde..95ab112b62ea5 100644
--- a/test/SILGen/opaque_result_type_nested_optional.swift
+++ b/test/SILGen/opaque_result_type_nested_optional.swift
@@ -11,5 +11,5 @@ _ = bar(foo())
 // CHECK: [[UNUSED:%.*]] = alloc_stack $S<Optional<Int>>
 // CHECK: [[INNER:%.*]] = alloc_stack $S<Optional<Int>>
 // CHECK: [[FN:%.*]] = function_ref @$s40opaque_result_type_nested_optional_other3bary1AQzxAA1PRzlF : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out τ_0_0.A
-// CHECK: apply [[FN]]<S<Int?>>([[OUTER]], [[INNER]]) : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out τ_0_0.A
+// CHECK: apply [[FN]]<S<Optional<Int>>>([[OUTER]], [[INNER]]) : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> @out τ_0_0.A
 // CHECK: return
diff --git a/test/SILGen/opaque_result_type_reduction_order.swift b/test/SILGen/opaque_result_type_reduction_order.swift
new file mode 100644
index 0000000000000..0714d75c05880
--- /dev/null
+++ b/test/SILGen/opaque_result_type_reduction_order.swift
@@ -0,0 +1,27 @@
+// RUN: %target-swift-emit-silgen %s
+
+protocol N {
+  associatedtype A: N
+}
+
+struct G<T>: N {
+  typealias A = G<G<T>>
+}
+
+protocol P<A> {
+  associatedtype A
+}
+
+struct GG<T>: P {
+  typealias A = T
+}
+
+func f<T: N>(_: T) -> some P<T.A.A> {
+  return GG<T.A.A>()
+}
+
+func g<T: P>(_: T) -> T.A { fatalError() }
+
+func h(_: G<G<G<Int>>>) {}
+
+h(g(f(G<Int>())))
diff --git a/test/SILGen/opaque_result_type_retroactive.swift b/test/SILGen/opaque_result_type_retroactive.swift
new file mode 100644
index 0000000000000..eaaabcb7ec57c
--- /dev/null
+++ b/test/SILGen/opaque_result_type_retroactive.swift
@@ -0,0 +1,31 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module %S/Inputs/opaque_result_type_retroactive_other.swift -emit-module -emit-module-path %t/opaque_result_type_retroactive_other.swiftmodule
+// RUN: %target-swift-emit-silgen %s -I %t | %FileCheck %s
+
+import opaque_result_type_retroactive_other
+
+extension G: @retroactive P where T: P {
+  public func a() -> T {
+    fatalError()
+  }
+}
+
+public struct S: P {
+  public func a() -> S {
+    return self
+  }
+}
+
+public func f() -> some P {
+  return S()
+}
+
+public struct OfP<T: P> {
+  public init(_: T) {}
+}
+
+// CHECK-LABEL: sil_global @$s30opaque_result_type_retroactive1xAA3OfPVy0a1_b1_c1_D6_other1GVyAA1fQryFQOyQo_GAjE1PAAxAeKHD1_AIHO_HCg_Gvp
+public var x = OfP(G(f()))
+
+// CHECK-LABEL: sil_global @$s30opaque_result_type_retroactive1yAA3OfPVy0a1_b1_c1_D6_other1GVyAA1fQryFQOyQo_1AAE1PPQxGAnekAxAeKHD1_AJQzAeKHA1_AMHO_HCg_Gvp
+public var y = OfP(G(f().a()))
diff --git a/test/SILGen/opaque_result_type_slow.swift b/test/SILGen/opaque_result_type_slow.swift
new file mode 100644
index 0000000000000..2cce2ae36295c
--- /dev/null
+++ b/test/SILGen/opaque_result_type_slow.swift
@@ -0,0 +1,32 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module %S/Inputs/opaque_result_type_slow_other.swift -emit-module -emit-module-path %t/opaque_result_type_slow_other.swiftmodule -enable-library-evolution
+// RUN: %target-swift-emit-silgen %s -I %t
+
+import opaque_result_type_slow_other
+
+struct G<T: P & Q>: P & Q {}
+
+public func myWrap<T: P & Q>(_ t: T) -> some P & Q {
+  return G<T>()
+}
+
+public func wrapWrap<T: P & Q>(_ t: T) -> some P & Q {
+  return wrap(wrap(myWrap(t)))
+}
+
+public struct S: P, Q {}
+
+// We generate a series of substitution maps where each one contains an opaque archetype,
+// and an abstract conformance of this opaque archetype to a protocol. Each opaque archetype
+// then has a substitution map of the same form, and so on.
+//
+// Transforming each substitution map then visits each opaque archetype twice: once as part
+// of the replacement type, and again as part of the conformance.
+//
+// What saves us is that we would skip the conformance substitution in some cases, and perform
+// a lookup instead. This lookup is now load bearing, because changing it into a substitution
+// makes this program intractably slow.
+//
+// The correct fix is to probably cache substituted opaque GenericEnvironments, or
+// substituted SubstitutionMaps, inside of the InFlightSubstitution.
+let x = wrapWrap(wrapWrap(wrapWrap(wrapWrap(wrapWrap(wrapWrap(wrapWrap(wrapWrap(wrapWrap(S())))))))))
diff --git a/test/SILGen/opaque_values_closures.swift b/test/SILGen/opaque_values_closures.swift
index f38221a3c0c97..b470357628d2e 100644
--- a/test/SILGen/opaque_values_closures.swift
+++ b/test/SILGen/opaque_values_closures.swift
@@ -43,7 +43,6 @@ struct G<T> {}
 struct MOG<T> : ~Copyable {}
 func getMOG<T>(_ t: T.Type) -> MOG<T> { return MOG<T>() }
 func borrow<T>(_ t: T) {}
-@propertyWrapper struct BoxWrapper<T> { var wrappedValue: T }
 
 // CaptureKind::Immutable, canGuarantee=true, isPack=true
 // CHECK-LABEL: sil {{.*}}[ossa] @$s22opaque_values_closures30captureImmutablePackGuaranteed1tyxxQp_tRvzlF6$deferL_yyRvzlF : {{.*}} {
@@ -357,32 +356,4 @@ func captureBoxNonopaqueOwnedEscaping() {
   }
 }
 func captureBoxNonopaqueOwnedEscaping_callee<T>(_ t: T, _ c: @escaping (T) -> ()) {}
-func captureBoxNonopaqueOwnedEscaping_vend() -> C { return C() }
-
-// CaptureKind::Box, non-opaque, canGuarantee=false, captureCanEscape=false
-// CHECK-LABEL: sil {{.*}}[ossa] @$s22opaque_values_closures35captureBoxNonopaqueOwnedNonescapingyyxyXElF : {{.*}} {
-// CHECK:       bb0([[GET:%[^,]+]] :
-// CHECK:         [[BOX:%[^,]+]] = alloc_box $<τ_0_0> { var BoxWrapper<τ_0_0> } <U>, var
-// CHECK:         [[VAR:%[^,]+]] = mark_uninitialized [var] [[BOX]]
-// CHECK:         [[VAR_LIFETIME:%[^,]+]] = begin_borrow [lexical] [var_decl] [[VAR]]
-// CHECK:         [[VAR_ADDR:%[^,]+]] = project_box [[VAR_LIFETIME]]
-// TODO: DETERMINE: Considering that captureCanEscape is false, should this mark_function_escape be emitted?
-// CHECK:         mark_function_escape [[VAR_ADDR]]
-// CHECK:         [[LOCAL:%[^,]+]] = function_ref @$s22opaque_values_closures35captureBoxNonopaqueOwnedNonescapingyyxyXElF5localL_yylF
-// CHECK:         apply [[LOCAL]]<U>([[VAR_LIFETIME]], [[GET]])
-// CHECK:         end_borrow [[VAR_LIFETIME]]
-// CHECK:         destroy_value [[VAR]]
-// CHECK-LABEL: } // end sil function '$s22opaque_values_closures35captureBoxNonopaqueOwnedNonescapingyyxyXElF'
-// CHECK-LABEL: sil {{.*}}[ossa] @$s22opaque_values_closures35captureBoxNonopaqueOwnedNonescapingyyxyXElF5localL_yylF : {{.*}}
-// CHECK:       bb0(%0 : @closureCapture @guaranteed $<τ_0_0> { var BoxWrapper<τ_0_0> } <U>, 
-// CHECK-SAME:      %1 :
-// CHECK-LABEL: } // end sil function '$s22opaque_values_closures35captureBoxNonopaqueOwnedNonescapingyyxyXElF5localL_yylF'
-func captureBoxNonopaqueOwnedNonescaping<U>(_ get: () -> U) {
-  @BoxWrapper var u: U
-
-  func local() {
-    u = get()
-  }
-  local()
-}
-
+func captureBoxNonopaqueOwnedEscaping_vend() -> C { return C() }
\ No newline at end of file
diff --git a/test/SILGen/opaque_values_cxx.swift b/test/SILGen/opaque_values_cxx.swift
index 5d08e68535e46..641b66c11a6a8 100644
--- a/test/SILGen/opaque_values_cxx.swift
+++ b/test/SILGen/opaque_values_cxx.swift
@@ -17,7 +17,7 @@ import Cxx
 // CHECK-LABEL: } // end sil function '$sSo3stdO3__1O0065vectorCUnsignedIntstd__1allocatorCUnsignedInt_dDGIrdqahddCJdFaAjaV3Cxx0B8SequenceSCAgHP13__beginUnsafe11RawIteratorQzyFTW'
 // CHECK-LABEL: sil {{.*}}[ossa] @$sSo3stdO{{(3__1O)?}}0047___wrap_iterUnsafePointerCUnsignedInt_heCInnaEgaVSQSCSQ2eeoiySbx_xtFZTW : {{.*}} {
 // CHECK:       bb0([[LHS:%[^,]+]] : $std.__1.__wrap_iter<UnsafePointer<CUnsignedInt>>, [[RHS:%[^,]+]] :
-// CHECK:         [[CALLEE:%[^,]+]] = function_ref @$sSo2eeoiySbSo3stdO{{(3__1O)?}}0047___wrap_iterUnsafePointerCUnsignedInt_heCInnaEgaV_AGtFTO
+// CHECK:         [[CALLEE:%[^,]+]] = function_ref @_ZNSt3__1eqB8ne{{.*}}IPKjEEbRKNS_11__wrap_iterIT_EES7_
 // CHECK:         [[EQUAL:%[^,]+]] = apply [[CALLEE]]([[LHS]], [[RHS]])
 // CHECK:         return [[EQUAL]]
 // CHECK-LABEL: } // end sil function '$sSo3stdO{{(3__1O)?}}0047___wrap_iterUnsafePointerCUnsignedInt_heCInnaEgaVSQSCSQ2eeoiySbx_xtFZTW'
diff --git a/test/SILGen/opaque_values_silgen.swift b/test/SILGen/opaque_values_silgen.swift
index 4923fde1e2bba..69bb687afb27a 100644
--- a/test/SILGen/opaque_values_silgen.swift
+++ b/test/SILGen/opaque_values_silgen.swift
@@ -221,7 +221,7 @@ func loadBorrow() {
 // Tests LogicalPathComponent's writeback for opaque value types
 // ---
 // Dictionary.subscript.getter
-// CHECK-LABEL: sil [always_inline] [ossa] @$sSD20opaque_values_silgenEyq_Sgq_cig : $@convention(method) <Key, Value where Key : Hashable> (@in_guaranteed Value, @guaranteed Dictionary<Key, Value>) -> @out Optional<Value> {
+// CHECK-LABEL: sil [heuristic_always_inline] [ossa] @$sSD20opaque_values_silgenEyq_Sgq_cig : $@convention(method) <Key, Value where Key : Hashable> (@in_guaranteed Value, @guaranteed Dictionary<Key, Value>) -> @out Optional<Value> {
 // HECK: bb0([[ARG0:%.*]] : $Value, [[ARG1:%.*]] : $*Dictionary<Key, Value>):
 // HECK:   [[WRITE:%.*]] = begin_access [modify] [unknown] [[ARG1]] : $*Dictionary<Key, Value>
 // HECK:   [[OPTIONAL_ALLOC:%.*]] = alloc_stack $Optional<Value>
@@ -875,7 +875,7 @@ struct Twople<T> {
   }
 }
 
-// CHECK-LABEL: sil{{.*}} [ossa] @throwTypedValue : {{.*}} {
+// CHECK-LABEL: sil{{.*}} [ossa] @throwTypedValue : {{.*}} -> @error Err {
 // CHECK:       bb0([[E:%[^,]+]] :
 // CHECK:         [[SWIFT_WILL_THROW_TYPED:%[^,]+]] = function_ref @swift_willThrowTyped
 // CHECK:         apply [[SWIFT_WILL_THROW_TYPED]]<Err>([[E]])
@@ -884,4 +884,66 @@ struct Twople<T> {
 @_silgen_name("throwTypedValue")
 func throwTypedValue(_ e: Err) throws(Err) { throw e }
 
+// CHECK-LABEL: sil{{.*}} [ossa] @callTypedThrowsFunc : {{.*}} -> @error any Error {
+// CHECK:       bb0:
+// CHECK:         [[TYPED_THROW_FN:%[^,]+]] = function_ref @throwTypedValue
+// CHECK:         try_apply [[TYPED_THROW_FN]]({{%[0-9]+}}) : $@convention(thin) (Err) -> @error Err, normal bb1, error bb2
+//
+// CHECK:       bb1({{%[0-9]+}} : $()):
+// CHECK:         return
+//
+// CHECK:       bb2([[E:%[^,]+]] : $Err):
+// CHECK:         [[STACK_ALLOC:%[^,]+]] = alloc_stack $any Error
+// CHECK:         [[BOX:%[^,]+]] = project_existential_box $Err
+// CHECK:         store [[E]] to [trivial] [[BOX]]
+// CHECK:         [[ANY_ERROR:%[^,]+]] = load [take] [[STACK_ALLOC]]
+// CHECK:         throw [[ANY_ERROR]]
+// CHECK-LABEL: } // end sil function 'callTypedThrowsFunc'
+@_silgen_name("callTypedThrowsFunc")
+func callTypedThrowsFunc() throws {
+  try throwTypedValue(Err())
+}
+
+// CHECK-LABEL: sil{{.*}} [ossa] @throwTypedValueGeneric : {{.*}} <GenErr where GenErr : Error> (@in_guaranteed GenErr) -> @error_indirect GenErr {
+// CHECK:       bb0([[BORROWED_ERR:%[^,]+]] : @guaranteed $GenErr):
+// CHECK:         [[E:%[^,]+]] = copy_value [[BORROWED_ERR]]
+// CHECK:         [[SWIFT_WILL_THROW_TYPED:%[^,]+]] = function_ref @swift_willThrowTyped
+// CHECK:         apply [[SWIFT_WILL_THROW_TYPED]]<GenErr>([[E]])
+// CHECK:         throw [[E]]
+// CHECK-LABEL: } // end sil function 'throwTypedValueGeneric'
+@_silgen_name("throwTypedValueGeneric")
+func throwTypedValueGeneric<GenErr: Error>(_ e: GenErr) throws(GenErr) { throw e }
+
+// CHECK-LABEL: sil{{.*}} [ossa] @callTypedThrowsFuncGeneric : {{.*}} -> @error any Error {
+// CHECK:       bb0:
+// CHECK:         [[ERR_VAL:%[^,]+]] = apply {{.*}} -> Err
+// CHECK:         [[GEN_TYPED_THROW_FN:%[^,]+]] = function_ref @throwTypedValueGeneric
+// CHECK:         try_apply [[GEN_TYPED_THROW_FN]]<Err>([[ERR_VAL]]) : $@convention(thin) <τ_0_0 where τ_0_0 : Error> (@in_guaranteed τ_0_0) -> @error_indirect τ_0_0, normal bb1, error bb2
+//
+// CHECK:       bb1({{%[0-9]+}} : $()):
+// CHECK:         return
+//
+// CHECK:       bb2([[E:%[^,]+]] : $Err):
+// CHECK:         [[STACK_ALLOC:%[^,]+]] = alloc_stack $any Error
+// CHECK:         [[BOX:%[^,]+]] = project_existential_box $Err
+// CHECK:         store [[E]] to [trivial] [[BOX]]
+// CHECK:         [[ANY_ERROR:%[^,]+]] = load [take] [[STACK_ALLOC]]
+// CHECK:         throw [[ANY_ERROR]]
+// CHECK-LABEL: } // end sil function 'callTypedThrowsFuncGeneric'
+@_silgen_name("callTypedThrowsFuncGeneric")
+func callTypedThrowsFuncGeneric() throws {
+  try throwTypedValueGeneric(Err())
+}
+
 struct Err : Error {}
+
+// CHECK-LABEL: sil{{.*}} [ossa] @copy_expr_generic : {{.*}} {
+// CHECK:       bb0([[E:%[^,]+]] : @guaranteed $T
+// CHECK:         [[E_COPY:%[^,]+]] = explicit_copy_value [[E]]
+// CHECK:         apply {{.*}}<T>([[E_COPY]])
+// CHECK-LABEL: } // end sil function 'copy_expr_generic'
+@_silgen_name("copy_expr_generic")
+func copy_expr_generic<T>(_ t: T)  {
+  eat_generic(copy t)
+}
+func eat_generic<T>(_ t: consuming T) {}
diff --git a/test/SILGen/package_allow_non_resilient_access.swift b/test/SILGen/package_allow_non_resilient_access.swift
index 6ee0f40924ca2..e8ad75dd4c086 100644
--- a/test/SILGen/package_allow_non_resilient_access.swift
+++ b/test/SILGen/package_allow_non_resilient_access.swift
@@ -44,7 +44,7 @@
 // RUN:   -experimental-allow-non-resilient-access \
 // RUN:   -emit-module -emit-module-path %t/Utils.swiftmodule \
 // RUN: 2>&1 | %FileCheck %s --check-prefix=CHECK-DIAG-1
-// CHECK-DIAG-1: warning: ignoring -experimental-skip-non-exportable-decls (overriden by -allow-non-resilient-access)
+// CHECK-DIAG-1: warning: ignoring -experimental-skip-non-exportable-decls (overridden by -allow-non-resilient-access)
 // RUN: llvm-bcanalyzer --dump %t/Utils.swiftmodule | %FileCheck %s --check-prefix=CHECK-ON
 
 /// Override -experimental-skip-non-inlinable-function-bodies-without-types with warning
@@ -57,7 +57,7 @@
 // RUN:   -experimental-allow-non-resilient-access \
 // RUN:   -emit-module -emit-module-path %t/Utils.swiftmodule \
 // RUN: 2>&1 | %FileCheck %s --check-prefix=CHECK-DIAG-2
-// CHECK-DIAG-2: warning: ignoring -experimental-skip-non-inlinable-function-bodies-without-types (overriden by -allow-non-resilient-access)
+// CHECK-DIAG-2: warning: ignoring -experimental-skip-non-inlinable-function-bodies-without-types (overridden by -allow-non-resilient-access)
 // RUN: llvm-bcanalyzer --dump %t/Utils.swiftmodule | %FileCheck %s --check-prefix=CHECK-ON
 
 /// Override -experimental-skip-non-inlinable-function-bodies with warning
@@ -70,7 +70,7 @@
 // RUN:   -experimental-allow-non-resilient-access \
 // RUN:   -emit-module -emit-module-path %t/Utils.swiftmodule \
 // RUN: 2>&1 | %FileCheck %s --check-prefix=CHECK-DIAG-3
-// CHECK-DIAG-3: warning: ignoring -experimental-skip-non-inlinable-function-bodies (overriden by -allow-non-resilient-access)
+// CHECK-DIAG-3: warning: ignoring -experimental-skip-non-inlinable-function-bodies (overridden by -allow-non-resilient-access)
 // RUN: llvm-bcanalyzer --dump %t/Utils.swiftmodule | %FileCheck %s --check-prefix=CHECK-ON
 
 /// Override -experimental-skip-all-function-bodies with warning
@@ -83,7 +83,7 @@
 // RUN:   -experimental-allow-non-resilient-access \
 // RUN:   -emit-module -emit-module-path %t/Utils.swiftmodule \
 // RUN: 2>&1 | %FileCheck %s --check-prefix=CHECK-DIAG-4
-// CHECK-DIAG-4: warning: ignoring -experimental-skip-all-function-bodies (overriden by -allow-non-resilient-access)
+// CHECK-DIAG-4: warning: ignoring -experimental-skip-all-function-bodies (overridden by -allow-non-resilient-access)
 // RUN: llvm-bcanalyzer --dump %t/Utils.swiftmodule | %FileCheck %s --check-prefix=CHECK-ON
 
 /// Override -experimental-lazy-typecheck with warning
@@ -96,7 +96,7 @@
 // RUN:   -experimental-allow-non-resilient-access \
 // RUN:   -emit-module -emit-module-path %t/Utils.swiftmodule \
 // RUN: 2>&1 | %FileCheck %s --check-prefix=CHECK-DIAG-5
-// CHECK-DIAG-5: warning: ignoring -experimental-lazy-typecheck (overriden by -allow-non-resilient-access)
+// CHECK-DIAG-5: warning: ignoring -experimental-lazy-typecheck (overridden by -allow-non-resilient-access)
 // RUN: llvm-bcanalyzer --dump %t/Utils.swiftmodule | %FileCheck %s --check-prefix=CHECK-ON
 
 /// Override -tbd-is-installapi with warning
@@ -109,7 +109,7 @@
 // RUN:   -experimental-allow-non-resilient-access \
 // RUN:   -emit-module -emit-module-path %t/Utils.swiftmodule \
 // RUN: 2>&1 | %FileCheck %s --check-prefix=CHECK-DIAG-TBD
-// CHECK-DIAG-TBD: warning: ignoring -tbd-is-installapi (overriden by -allow-non-resilient-access)
+// CHECK-DIAG-TBD: warning: ignoring -tbd-is-installapi (overridden by -allow-non-resilient-access)
 // RUN: llvm-bcanalyzer --dump %t/Utils.swiftmodule | %FileCheck %s --check-prefix=CHECK-ON
 
 /// Build Utils interface files.
@@ -130,7 +130,7 @@
 // RUN: -allow-non-resilient-access \
 // RUN: %t/Utils.package.swiftinterface -o %t/Utils.swiftmodule \
 // RUN: 2>&1 | %FileCheck %s --check-prefix=CHECK-DIAG-INTERFACE
-// CHECK-DIAG-INTERFACE: warning: ignoring -allow-non-resilient-access (overriden by -compile-module-from-interface or -typecheck-module-from-interface)
+// CHECK-DIAG-INTERFACE: warning: ignoring -allow-non-resilient-access (overridden by -compile-module-from-interface)
 // RUN: llvm-bcanalyzer --dump %t/Utils.swiftmodule | %FileCheck %s --check-prefix=CHECK-OFF
 // CHECK-OFF-NOT: ALLOW_NON_RESILIENT_ACCESS
 
diff --git a/test/SILGen/parameterized_existential_composition.swift b/test/SILGen/parameterized_existential_composition.swift
new file mode 100644
index 0000000000000..e14a3a48a0c94
--- /dev/null
+++ b/test/SILGen/parameterized_existential_composition.swift
@@ -0,0 +1,40 @@
+// RUN: %target-swift-emit-silgen -disable-availability-checking %s | %FileCheck %s
+
+protocol P<A> {
+  associatedtype A
+}
+
+protocol Q<B> {
+  associatedtype B
+}
+
+// All of these should have unique mangling.
+func overload(_: any P<Int> & Q<String>) {}
+func overload(_: any P<Float> & Q<String>) {}
+func overload(_: any P & Q<String>) {}
+func overload(_: any P<Int> & Q<Bool>) {}
+func overload(_: any P<Float> & Q<Bool>) {}
+func overload(_: any P & Q<Bool>) {}
+func overload(_: any P<Int> & Q) {}
+func overload(_: any P<Float> & Q) {}
+func overload(_: any P & Q) {}
+func overload(_: any P<Int>) {}
+func overload(_: any P<Float>) {}
+func overload(_: any P) {}
+func overload(_: any Q<Bool>) {}
+func overload(_: any Q) {}
+
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSi1AAaCPRts_SS1BAaDPRtsXPF : $@convention(thin) (@in_guaranteed any P<Int> & Q<String>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSf1AAaCPRts_SS1BAaDPRtsXPF : $@convention(thin) (@in_guaranteed any P<Float> & Q<String>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSS1BAaDPRts_XPF : $@convention(thin) (@in_guaranteed any P & Q<String>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSi1AAaCPRts_Sb1BAaDPRtsXPF : $@convention(thin) (@in_guaranteed any P<Int> & Q<Bool>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSf1AAaCPRts_Sb1BAaDPRtsXPF : $@convention(thin) (@in_guaranteed any P<Float> & Q<Bool>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSb1BAaDPRts_XPF : $@convention(thin) (@in_guaranteed any P & Q<Bool>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSi1AAaCPRts_XPF : $@convention(thin) (@in_guaranteed any P<Int> & Q) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSf1AAaCPRts_XPF : $@convention(thin) (@in_guaranteed any P<Float> & Q) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpF : $@convention(thin) (@in_guaranteed any P & Q) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_pSi1AAaCPRts_XPF : $@convention(thin) (@in_guaranteed any P<Int>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_pSf1AAaCPRts_XPF : $@convention(thin) (@in_guaranteed any P<Float>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_pF : $@convention(thin) (@in_guaranteed any P) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1Q_pSb1BAaCPRts_XPF : $@convention(thin) (@in_guaranteed any Q<Bool>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1Q_pF : $@convention(thin) (@in_guaranteed any Q) -> () {
diff --git a/test/SILGen/pointer_conversion.swift b/test/SILGen/pointer_conversion.swift
index 93dfa9e0e2e7e..fbe555d909634 100644
--- a/test/SILGen/pointer_conversion.swift
+++ b/test/SILGen/pointer_conversion.swift
@@ -1,4 +1,7 @@
-// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -module-name pointer_conversion -sdk %S/Inputs -I %S/Inputs -enable-source-import %s -enable-objc-interop | %FileCheck %s
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -module-name pointer_conversion \
+// RUN:   -sdk %S/Inputs -I %S/Inputs -enable-source-import %s -enable-objc-interop \
+// RUN:   -import-objc-header %S/Inputs/readbytes.h \
+// RUN:   | %FileCheck %s
 
 // FIXME: rdar://problem/19648117 Needs splitting objc parts out
 // REQUIRES: objc_interop
@@ -138,6 +141,56 @@ func arrayToPointer() {
   // CHECK: [[TAKES_OPT_CONST_POINTER:%.*]] = function_ref @$s18pointer_conversion20takesOptConstPointer_3andySPySiGSg_SitF :
   // CHECK: apply [[TAKES_OPT_CONST_POINTER]]([[OPTPTR]], [[RESULT1]])
   // CHECK: destroy_value [[OWNER]]
+
+  // -- test implicit conversions allowed by C functions
+  read_char(ints)
+  // CHECK: [[CONVERT_FN:%.*]] = function_ref @$ss35_convertConstArrayToPointerArgumentyyXlSg_q_tSayxGs01_E0R_r0_lF
+  // CHECK: apply [[CONVERT_FN]]<Int, UnsafePointer<Int8>>([[PTR_RESULT:%[0-9]+]], {{.*}})
+  // CHECK: [[PTR:%[0-9]+]] = load [trivial] [[PTR_RESULT]] : $*UnsafePointer<Int8>
+  // CHECK: [[PTR_MD:%[0-9]+]] = mark_dependence [[PTR]] : $UnsafePointer<Int8> on
+  // CHECK: [[PTR_OPT:%[0-9]+]] = enum $Optional<UnsafePointer<Int8>>, #Optional.some!enumelt, [[PTR_MD]]
+  // CHECK: [[READ_FN:%.*]] = function_ref @read_char : $@convention(c) (Optional<UnsafePointer<Int8>>) -> ()
+  // CHECK: apply [[READ_FN]]([[PTR_OPT]]) : $@convention(c) (Optional<UnsafePointer<Int8>>) -> ()
+  read_uchar(ints);
+  // CHECK: [[CONVERT_FN:%.*]] = function_ref @$ss35_convertConstArrayToPointerArgumentyyXlSg_q_tSayxGs01_E0R_r0_lF
+  // CHECK: apply [[CONVERT_FN]]<Int, UnsafePointer<UInt8>>([[PTR_RESULT:%[0-9]+]], {{.*}})
+  // CHECK: [[PTR:%[0-9]+]] = load [trivial] [[PTR_RESULT]] : $*UnsafePointer<UInt8>
+  // CHECK: [[PTR_MD:%[0-9]+]] = mark_dependence [[PTR]] : $UnsafePointer<UInt8> on
+  // CHECK: [[PTR_OPT:%[0-9]+]] = enum $Optional<UnsafePointer<UInt8>>, #Optional.some!enumelt, [[PTR_MD]]
+  // CHECK: [[READ_FN:%.*]] = function_ref @read_uchar : $@convention(c) (Optional<UnsafePointer<UInt8>>) -> ()
+  // CHECK: apply [[READ_FN]]([[PTR_OPT]]) : $@convention(c) (Optional<UnsafePointer<UInt8>>) -> ()
+  read_void(ints);
+  // CHECK: [[CONVERT_FN:%.*]] = function_ref @$ss35_convertConstArrayToPointerArgumentyyXlSg_q_tSayxGs01_E0R_r0_lF
+  // CHECK: apply [[CONVERT_FN]]<Int, UnsafeRawPointer>([[PTR_RESULT:%[0-9]+]], {{.*}})
+  // CHECK: [[PTR:%[0-9]+]] = load [trivial] [[PTR_RESULT]] : $*UnsafeRawPointer
+  // CHECK: [[PTR_MD:%[0-9]+]] = mark_dependence [[PTR]] : $UnsafeRawPointer on
+  // CHECK: [[PTR_OPT:%[0-9]+]] = enum $Optional<UnsafeRawPointer>, #Optional.some!enumelt, [[PTR_MD]]
+  // CHECK: [[READ_FN:%.*]] = function_ref @read_void : $@convention(c) (Optional<UnsafeRawPointer>) -> ()
+  // CHECK: apply [[READ_FN]]([[PTR_OPT]]) : $@convention(c) (Optional<UnsafeRawPointer>) -> ()
+  write_char(&ints);
+  // CHECK: [[CONVERT_FN:%.*]] = function_ref @$ss37_convertMutableArrayToPointerArgumentyyXlSg_q_tSayxGzs01_E0R_r0_lF
+  // CHECK: apply [[CONVERT_FN]]<Int, UnsafeMutablePointer<Int8>>([[PTR_RESULT:%[0-9]+]], {{.*}})
+  // CHECK: [[PTR:%[0-9]+]] = load [trivial] [[PTR_RESULT]] : $*UnsafeMutablePointer<Int8>
+  // CHECK: [[PTR_MD:%[0-9]+]] = mark_dependence [[PTR]] : $UnsafeMutablePointer<Int8> on
+  // CHECK: [[PTR_OPT:%[0-9]+]] = enum $Optional<UnsafeMutablePointer<Int8>>, #Optional.some!enumelt, [[PTR_MD]]
+  // CHECK: [[WRITE_FN:%.*]] = function_ref @write_char : $@convention(c) (Optional<UnsafeMutablePointer<Int8>>) -> ()
+  // CHECK: apply [[WRITE_FN]]([[PTR_OPT]]) : $@convention(c) (Optional<UnsafeMutablePointer<Int8>>) -> ()
+  write_uchar(&ints);
+  // CHECK: [[CONVERT_FN:%.*]] = function_ref @$ss37_convertMutableArrayToPointerArgumentyyXlSg_q_tSayxGzs01_E0R_r0_lF
+  // CHECK: apply [[CONVERT_FN]]<Int, UnsafeMutablePointer<UInt8>>([[PTR_RESULT:%[0-9]+]], {{.*}})
+  // CHECK: [[PTR:%[0-9]+]] = load [trivial] [[PTR_RESULT]] : $*UnsafeMutablePointer<UInt8>
+  // CHECK: [[PTR_MD:%[0-9]+]] = mark_dependence [[PTR]] : $UnsafeMutablePointer<UInt8> on
+  // CHECK: [[PTR_OPT:%[0-9]+]] = enum $Optional<UnsafeMutablePointer<UInt8>>, #Optional.some!enumelt, [[PTR_MD]]
+  // CHECK: [[WRITE_FN:%.*]] = function_ref @write_uchar : $@convention(c) (Optional<UnsafeMutablePointer<UInt8>>) -> ()
+  // CHECK: apply [[WRITE_FN]]([[PTR_OPT]]) : $@convention(c) (Optional<UnsafeMutablePointer<UInt8>>) -> ()
+  write_void(&ints);
+  // CHECK: [[CONVERT_FN:%.*]] = function_ref @$ss37_convertMutableArrayToPointerArgumentyyXlSg_q_tSayxGzs01_E0R_r0_lF
+  // CHECK: apply [[CONVERT_FN]]<Int, UnsafeMutableRawPointer>([[PTR_RESULT:%[0-9]+]], {{.*}})
+  // CHECK: [[PTR:%[0-9]+]] = load [trivial] [[PTR_RESULT]] : $*UnsafeMutableRawPointer
+  // CHECK: [[PTR_MD:%[0-9]+]] = mark_dependence [[PTR]] : $UnsafeMutableRawPointer on
+  // CHECK: [[PTR_OPT:%[0-9]+]] = enum $Optional<UnsafeMutableRawPointer>, #Optional.some!enumelt, [[PTR_MD]]
+  // CHECK: [[WRITE_FN:%.*]] = function_ref @write_void : $@convention(c) (Optional<UnsafeMutableRawPointer>) -> ()
+  // CHECK: apply [[WRITE_FN]]([[PTR_OPT]]) : $@convention(c) (Optional<UnsafeMutableRawPointer>) -> ()
 }
 
 // CHECK-LABEL: sil hidden [ossa] @$s18pointer_conversion15stringToPointeryySSF
@@ -481,3 +534,21 @@ public struct RefObj {
 public func objectFieldToPointer(rc: RefObj) {
   takeObjectPointer(&rc.o.object)
 }
+
+// CHECK-LABEL: sil [ossa] @$s18pointer_conversion21testVariadicParameter1aySaySiGz_tF : $@convention(thin) (@inout Array<Int>) -> ()
+// CHECK: [[ARRAY_REF:%.*]] = begin_access [modify] [unknown] %0 : $*Array<Int>
+// CHECK: [[CONVERT_ARRAY_TO_POINTER:%.*]] = function_ref @$ss37_convertMutableArrayToPointerArgumentyyXlSg_q_tSayxGzs01_E0R_r0_lF
+// CHECK: apply [[CONVERT_ARRAY_TO_POINTER]]<Int, UnsafeMutableRawPointer>({{.*}}, [[ARRAY_REF]])
+// CHECK: [[V_REF:%.*]] = begin_access [modify] [unknown] %28 : $*Double
+// CHECK: [[DOUBLE_AS_PTR:%.*]] = address_to_pointer [stack_protection] [[V_REF]] : $*Double to $Builtin.RawPointer
+// CHECK: [[INOUT_TO_PTR:%.*]] = function_ref @$ss30_convertInOutToPointerArgumentyxBps01_E0RzlF
+// CHECK: apply [[INOUT_TO_PTR]]<UnsafeMutableRawPointer>(%39, [[DOUBLE_AS_PTR]])
+// CHECK: } // end sil function '$s18pointer_conversion21testVariadicParameter1aySaySiGz_tF'
+public func testVariadicParameter(a: inout [Int]) {
+  func test(_ : UnsafeMutableRawPointer?...) {}
+
+  test(&a)
+
+  var v: Double
+  test(&v)
+}
diff --git a/test/SILGen/pr-84149.swift b/test/SILGen/pr-84149.swift
new file mode 100644
index 0000000000000..c35a4cd0be188
--- /dev/null
+++ b/test/SILGen/pr-84149.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-emit-silgen %s -verify
+
+enum E : Error {
+  case a(Int), b(Int)
+}
+
+func bar() throws {}
+
+// Make sure we can correctly emit this without crashing.
+func foo() throws {
+  do {
+    try bar()
+  } catch E.a, E.b {
+  }
+}
diff --git a/test/SILGen/preconcurrency-bridged-return.swift b/test/SILGen/preconcurrency-bridged-return.swift
new file mode 100644
index 0000000000000..d7a4d7a83c327
--- /dev/null
+++ b/test/SILGen/preconcurrency-bridged-return.swift
@@ -0,0 +1,8 @@
+// RUN: %target-swift-emit-silgen(mock-sdk: %clang-importer-sdk) -import-objc-header %S/Inputs/preconcurrency-bridged-return.h -swift-version 5 %s
+//
+// REQUIRES: objc_interop
+
+func test(x: TestClass) {
+	let foo = x.foo()
+}
+
diff --git a/test/SILGen/preconcurrency_indirect_return.swift b/test/SILGen/preconcurrency_indirect_return.swift
new file mode 100644
index 0000000000000..e5ceffe8a058d
--- /dev/null
+++ b/test/SILGen/preconcurrency_indirect_return.swift
@@ -0,0 +1,10 @@
+// RUN: %target-swift-emit-silgen %s | %FileCheck %s
+
+@preconcurrency
+func test() -> (any Sendable)? { nil }
+
+// CHECK-LABEL: sil {{.*}} @$s{{.*}}callWithPreconcurrency
+func callWithPreconcurrency() {
+	// CHECK: unchecked_addr_cast {{.*}} to $*Optional<any Sendable>
+	let x = test()
+}
diff --git a/test/SILGen/property_wrapper_local.swift b/test/SILGen/property_wrapper_local.swift
index 99c0a9d2142c0..72f697b6151f5 100644
--- a/test/SILGen/property_wrapper_local.swift
+++ b/test/SILGen/property_wrapper_local.swift
@@ -21,13 +21,13 @@ func testLocalWrapper() {
   // CHECK: [[P:%.*]] = project_box [[WLIFETIME]] : ${ var Wrapper<Int> }
 
   value = 10
-  // CHECK: [[I:%.*]] = function_ref @$s22property_wrapper_local16testLocalWrapperyyF5valueL_SivpfP : $@convention(thin) (Int) -> Wrapper<Int>
-  // CHECK: [[IPA:%.*]] = partial_apply [callee_guaranteed] [[I]]() : $@convention(thin) (Int) -> Wrapper<Int>
+  // CHECK: [[I:%.*]] = function_ref  @$s22property_wrapper_local16testLocalWrapperyyF5valueL_SivpfF : $@convention(thin) (Int) -> @out Wrapper<Int>
+  // CHECK: [[IPA:%.*]] = partial_apply [callee_guaranteed] [[I]]() : $@convention(thin) (Int) -> @out Wrapper<Int>
   // CHECK: [[S:%.*]] = function_ref @$s22property_wrapper_local16testLocalWrapperyyF5valueL_Sivs : $@convention(thin) (Int, @guaranteed { var Wrapper<Int> }) -> ()
   // CHECK-NEXT: [[C:%.*]] = copy_value [[WLIFETIME]] : ${ var Wrapper<Int> }
   // CHECK-NOT: mark_function_escape
   // CHECK-NEXT: [[SPA:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[S]]([[C]]) : $@convention(thin) (Int, @guaranteed { var Wrapper<Int> }) -> ()
-  // CHECK-NEXT: assign_by_wrapper {{%.*}} : $Int to [[P]] : $*Wrapper<Int>, init [[IPA]] : $@callee_guaranteed (Int) -> Wrapper<Int>, set [[SPA]] : $@noescape @callee_guaranteed (Int) -> ()
+  // CHECK-NEXT: assign_or_init #value, local [[P]] : $*Wrapper<Int>, value {{%.*}} : $Int, init [[IPA]] : $@callee_guaranteed (Int) -> @out Wrapper<Int>, set [[SPA]] : $@noescape @callee_guaranteed (Int) -> ()
 
   _ = value
   // CHECK: mark_function_escape [[P]] : $*Wrapper<Int>
@@ -46,12 +46,12 @@ func testLocalWrapper() {
   // CHECK: [[OP:%.*]] = function_ref @$sSi2peoiyySiz_SitFZ : $@convention(method) (@inout Int, Int, @thin Int.Type) -> ()
   // CHECK: apply [[OP]]({{%.*}}) : $@convention(method) (@inout Int, Int, @thin Int.Type) -> ()
   // CHECK: [[RESULT:%.*]] = load [trivial] [[TMP]] : $*Int
-  // CHECK: assign_by_wrapper [[RESULT]] : $Int to [[P]]
+  // CHECK: assign_or_init #value, local [[P]] : $*Wrapper<Int>, value [[RESULT]]
 
   // Check local property wrapper backing initializer and accessors
 
-  // property wrapper backing initializer of value #1 in testLocalWrapper()
-  // CHECK-LABEL: sil private [ossa] @$s22property_wrapper_local16testLocalWrapperyyF5valueL_SivpfP : $@convention(thin) (Int) -> Wrapper<Int> {
+  // property wrapped field init accessor of value #1 in testLocalWrapper()
+  // CHECK-LABEL: sil private [ossa] @$s22property_wrapper_local16testLocalWrapperyyF5valueL_SivpfF : $@convention(thin) (Int) -> @out Wrapper<Int> {
 
   // getter of $value #1 in testLocalWrapper()
   // CHECK-LABEL: sil private [ossa] @$s22property_wrapper_local16testLocalWrapperyyF6$valueL_AA0F0VySiGvg : $@convention(thin) (@guaranteed { var Wrapper<Int> }) -> Wrapper<Int> {
@@ -71,12 +71,12 @@ func testInitialValue() {
 
   value = 15
   // CHECK: function_ref @$s22property_wrapper_local16testInitialValueyyF5valueL_Sivs : $@convention(thin) (Int, @guaranteed { var Wrapper<Int> }) -> ()
-  // CHECK-NOT: assign_by_wrapper
+  // CHECK-NOT: assign_or_init
 
   value += 5
   // CHECK: function_ref @$sSi2peoiyySiz_SitFZ : $@convention(method) (@inout Int, Int, @thin Int.Type) -> ()
   // CHECK: function_ref @$s22property_wrapper_local16testInitialValueyyF5valueL_Sivs : $@convention(thin) (Int, @guaranteed { var Wrapper<Int> }) -> ()
-  // CHECK-NOT: assign_by_wrapper
+  // CHECK-NOT: assign_or_init
 
   // CHECK: return
 }
diff --git a/test/SILGen/property_wrappers.swift b/test/SILGen/property_wrappers.swift
index f4f8ae18dab9e..33c33052cbbd4 100644
--- a/test/SILGen/property_wrappers.swift
+++ b/test/SILGen/property_wrappers.swift
@@ -738,8 +738,9 @@ public class TestClass<T> {
   // CHECK-LABEL: sil [ossa] @$s17property_wrappers9TestClassC5valuexvpfP : $@convention(thin) <T> (@in T) -> @out WrapperWithInitialValue<T>
 
   // CHECK-LABEL: sil hidden [ossa] @$s17property_wrappers9TestClassC5value8protocolACyxGx_qd__tcAA0C8ProtocolRd__lufc
-  // CHECK: [[BACKING_INIT:%.*]] = function_ref @$s17property_wrappers9TestClassC5valuexvpfP : $@convention(thin) <τ_0_0> (@in τ_0_0) -> @out WrapperWithInitialValue<τ_0_0>
-  // CHECK-NEXT: partial_apply [callee_guaranteed] [[BACKING_INIT]]<T>()
+  // CHECK: [[BACKING_INIT:%.*]] = function_ref @$s17property_wrappers9TestClassC5valuexvpfF : $@convention(thin) <τ_0_0> (@in τ_0_0, @thick TestClass<τ_0_0>.Type) -> @out WrapperWithInitialValue<τ_0_0>
+  // CHECK: [[METATYPE:%.*]] = value_metatype $@thick TestClass<T>.Type 
+  // CHECK: partial_apply [callee_guaranteed] [[BACKING_INIT]]<T>([[METATYPE]])
   init<U: TestProtocol>(value: T, protocol: U) {
     self.value = value
   }
@@ -796,7 +797,7 @@ open class TestMyWrapper {
 extension UsesMyPublished {
   // CHECK-LABEL: sil hidden [ossa] @$s21property_wrapper_defs15UsesMyPublishedC0A9_wrappersE6setFooyySiF : $@convention(method) (Int, @guaranteed UsesMyPublished) -> ()
   // CHECK: class_method %1 : $UsesMyPublished, #UsesMyPublished.foo!setter
-  // CHECK-NOT: assign_by_wrapper
+  // CHECK-NOT: assign_or_init
   // CHECK: return
   func setFoo(_ x: Int) {
     foo = x
@@ -883,7 +884,7 @@ struct ObservedObject<ObjectType : AnyObject > {
 
 
 // rdar://problem/60600911
-// Ensure assign_by_wrapper is emitted for initialization
+// Ensure assign_or_init is emitted for initialization
 // of a property wrapper with a nonmutating set. Even though such setters
 // take `self` by-value.
 @propertyWrapper
@@ -904,7 +905,7 @@ struct NonMutatingWrapperTestStruct {
     // CHECK-LABEL: sil hidden [ossa] @$s17property_wrappers28NonMutatingWrapperTestStructV3valACSi_tcfC : $@convention(method) (Int, @thin NonMutatingWrapperTestStruct.Type) -> NonMutatingWrapperTestStruct {
     // CHECK: %[[LOAD:[0-9]+]] = load [trivial] %[[SRC:[0-9]+]] : $*NonMutatingWrapperTestStruct
     // CHECK-NEXT: %[[SET_PA:[0-9]+]] = partial_apply [callee_guaranteed] [on_stack] %[[PW_SETTER:[0-9]+]](%[[LOAD]]) : $@convention(method) (Int, NonMutatingWrapperTestStruct) -> ()
-    // CHECK-NEXT: assign_by_wrapper %[[SETVAL:[0-9]+]] : $Int to %[[ADDR:[0-9]+]] : $*NonMutatingSetterWrapper<Int>, init %[[INIT_PA:[0-9]+]] : $@callee_guaranteed (Int) -> NonMutatingSetterWrapper<Int>, set %[[SET_PA]] : $@noescape @callee_guaranteed (Int) -> ()
+    // CHECK-NEXT: assign_or_init #NonMutatingWrapperTestStruct.SomeProp, self %[[ADDR:[0-9]+]] : $*NonMutatingWrapperTestStruct, value %[[SETVAL:[0-9]+]] : $Int, init %[[INIT_PA:[0-9]+]] : $@callee_guaranteed (Int) -> @out NonMutatingSetterWrapper<Int>, set %[[SET_PA]] : $@noescape @callee_guaranteed (Int) -> ()    
     @NonMutatingSetterWrapper var SomeProp: Int
     init(val: Int) {
         SomeProp = val
diff --git a/test/SILGen/protocol-static-reqt-objc-class-impl.swift b/test/SILGen/protocol-static-reqt-objc-class-impl.swift
new file mode 100644
index 0000000000000..20d08b95ed79a
--- /dev/null
+++ b/test/SILGen/protocol-static-reqt-objc-class-impl.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-emit-silgen(mock-sdk: %clang-importer-sdk) -import-objc-header %S/Inputs/protocol-static-reqt-objc-class-impl.h %s -verify
+// REQUIRES: objc_interop
+
+protocol P {
+	static func foo() -> Self
+}
+
+extension C: P {}
+
diff --git a/test/SILGen/protocol_operators_local_conformance.swift b/test/SILGen/protocol_operators_local_conformance.swift
index c33341c3ecae3..9460175b528e0 100644
--- a/test/SILGen/protocol_operators_local_conformance.swift
+++ b/test/SILGen/protocol_operators_local_conformance.swift
@@ -64,7 +64,7 @@ func test6() {
 // CHECK: function_ref @$[[TEST6_EQUALS_WITNESS:[_0-9a-zA-Z]+]]
 // CHECK: }
 
-// CHECK: sil [serialized] @$[[TEST6_EQUALS_WITNESS]] : $@convention(thin) <τ_0_0 where τ_0_0 : RawRepresentable, τ_0_0.RawValue : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0) -> Bool
+// CHECK: sil [serialized] {{.*}}@$[[TEST6_EQUALS_WITNESS]] : $@convention(thin) <τ_0_0 where τ_0_0 : RawRepresentable, τ_0_0.RawValue : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0) -> Bool
 
 func test7() {
   struct Outer {
diff --git a/test/SILGen/protocol_packs.swift b/test/SILGen/protocol_packs.swift
new file mode 100644
index 0000000000000..31811c11b9e75
--- /dev/null
+++ b/test/SILGen/protocol_packs.swift
@@ -0,0 +1,245 @@
+// RUN: %target-swift-emit-silgen -target %target-swift-5.9-abi-triple -module-name test %s | %FileCheck %s
+
+// A trivial generic type.
+struct EmptyGeneric<T> {}
+
+// A non-trivial generic type.
+struct NonTrivialGeneric<T> {
+  var label: String
+}
+
+public protocol PackProvider<Pack> {
+  associatedtype Pack
+
+  func withFunction<each A>(_ encode: (repeat each A) -> Void)
+    where Pack == (repeat each A)
+}
+
+// #81002. Make sure we apply substitutions to the abstraction pattern when
+// calling a protocol requirement with variadic generic arguments,
+// because we may need them when propagating patterns down to expressions
+// that are sensitive to variadic expansion --- in this case, the
+// argument list of the closure.
+//
+// The `where` clause on the protocol requirement above isn't strictly
+// necessary; we'd just need some other way to constrain the pack while
+// also having a closure like this.
+func testClosure<E: PackProvider<(String, Int)>>(provider: E) {
+  //   Just check that we emitted the closure with a pack argument, which
+  //   implies that we've done substitution into the AP and aligned the
+  //   types properly.
+  // CHECK-LABEL: sil private [ossa] @$s4test0A7Closure8provideryx_tAA12PackProviderRzSS_Sit0D0RtzlFySS_SitXEfU_ : $@convention(thin) @substituted <each τ_0_0> (@pack_guaranteed Pack{repeat each τ_0_0}) -> () for <Pack{String, Int}>
+  provider.withFunction { (first, second) in }
+}
+
+// #80995. An assertion in reabstraction (in this case, the implicit
+// reabstraction of a protocol conformance thunk) when forwarding an
+// indirect tuple parameter to an expanded tuple parameter.
+public protocol Schema<Value>: Sendable {
+  associatedtype Value
+
+  func encode(_ value: Value, to encoder: Encoder<Self>) throws
+}
+
+public struct Encoder<Schema> {}
+
+private struct TupleSchema<each ElementSchema: Schema>: Schema {
+  typealias Value = (repeat (each ElementSchema).Value)
+
+  func encode(_ value: Value, to encoder: Encoder<Self>) throws {}
+}
+
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s4test11TupleSchema33_6C2FE3D25D7EB8B34759FC7B1028DF25LLVyxxQp_QPGAA0C0A2aFP6encode_2toy5ValueQz_AA7EncoderVyxGtKFTW :
+// CHECK-SAME:    $@convention(witness_method: Schema) <each τ_0_0 where repeat each τ_0_0 : Schema> (@in_guaranteed (repeat (each τ_0_0).Value), Encoder<TupleSchema<repeat each τ_0_0>>, @in_guaranteed TupleSchema<repeat each τ_0_0>) -> @error any Error
+
+//   The thunk receives a tuple indirectly, but the witness receives a pack of
+//   elements, so we have to initialize a pack with the tuple elements.
+// CHECK:       bb0(%0 : $*(repeat (each τ_0_0).Value), %1 : $Encoder<TupleSchema<repeat each τ_0_0>>, %2 : $*TupleSchema<repeat each τ_0_0>):
+// CHECK-NEXT:    [[PACK:%.*]] = alloc_pack $Pack{repeat (each τ_0_0).Value}
+// CHECK-NEXT:    [[ZERO:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK-NEXT:    [[ONE:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK-NEXT:    [[LENGTH:%.*]] = pack_length $Pack{repeat each τ_0_0}
+// CHECK-NEXT:    br bb1([[ZERO]])
+// CHECK:       bb1([[INDEX:%.*]] : $Builtin.Word):
+// CHECK-NEXT:    [[DONE:%.*]] = builtin "cmp_eq_Word"([[INDEX]], [[LENGTH]])
+// CHECK-NEXT:    cond_br [[DONE]], bb3, bb2
+// CHECK:       bb2:
+// CHECK-NEXT:    [[PACK_INDEX:%.*]] = dynamic_pack_index [[INDEX]] of $Pack{repeat (each τ_0_0).Value}
+// CHECK-NEXT:    open_pack_element [[PACK_INDEX]] of <each τ_0_0 where repeat each τ_0_0 : Schema> at <Pack{repeat each τ_0_0}>, shape $each τ_0_0, uuid [[UUID:".*"]]
+// CHECK-NEXT:    [[ELT_ADDR:%.*]] = tuple_pack_element_addr [[PACK_INDEX]] of %0 as $*@pack_element([[UUID]]) (each τ_0_0).Value
+// CHECK-NEXT:    pack_element_set [[ELT_ADDR]] into [[PACK_INDEX]] of [[PACK]]
+// CHECK-NEXT:    [[NEXT_INDEX:%.*]] = builtin "add_Word"([[INDEX]], [[ONE]])
+// CHECK-NEXT:    br bb1([[NEXT_INDEX]])
+
+// #81600. An assertion in reabstraction (again, from a witness thunk)
+// when forwarding pack parameters that aren't simple `each T`s.
+protocol PackAccepter {
+  func accept<each T>(values: repeat EmptyGeneric<each T>)
+}
+
+struct AccepterImpl: PackAccepter {
+  func accept<each T>(values: repeat EmptyGeneric<each T>) {}
+}
+
+//   Just produce a new pack with the same contents.
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s4test12AccepterImplVAA04PackB0A2aDP6accept6valuesyAA12EmptyGenericVyqd__Gqd__Qp_tRvd__lFTW :
+// CHECK:         [[PACK:%.*]] = alloc_pack $Pack{repeat EmptyGeneric<each τ_0_0>}
+// CHECK-NEXT:    [[ZERO:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK-NEXT:    [[ONE:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK-NEXT:    [[LENGTH:%.*]] = pack_length $Pack{repeat each τ_0_0}
+// CHECK-NEXT:    br bb1([[ZERO]])
+// CHECK:       bb1([[INDEX:%.*]] : $Builtin.Word):
+// CHECK-NEXT:    [[DONE:%.*]] = builtin "cmp_eq_Word"([[INDEX]], [[LENGTH]])
+// CHECK-NEXT:    cond_br [[DONE]], bb3, bb2
+// CHECK:       bb2:
+// CHECK-NEXT:    [[PACK_INDEX:%.*]] = dynamic_pack_index [[INDEX]] of $Pack{repeat EmptyGeneric<each τ_0_0>}
+// CHECK-NEXT:    open_pack_element [[PACK_INDEX]] of <each τ_0_0> at <Pack{repeat each τ_0_0}>, shape $each τ_0_0, uuid [[UUID:".*"]]
+// CHECK-NEXT:    [[ARG_ADDR:%.*]] = pack_element_get [[PACK_INDEX]] of %0 as $*EmptyGeneric<@pack_element([[UUID]]) each τ_0_0>
+// CHECK-NEXT:    pack_element_set [[ARG_ADDR]] into [[PACK_INDEX]] of [[PACK]]
+// CHECK-NEXT:    [[NEXT_INDEX:%.*]] = builtin "add_Word"([[INDEX]], [[ONE]])
+// CHECK-NEXT:    br bb1([[NEXT_INDEX]])
+
+protocol ConsumingAccepter {
+  func accept<each T>(values: repeat consuming NonTrivialGeneric<each T>)
+}
+
+struct ConsumingConsumingAccepterImpl: ConsumingAccepter {
+  func accept<each T>(values: repeat consuming NonTrivialGeneric<each T>) {}
+}
+
+//   This is actually just checking that consuming parameter packs
+//   work in general.
+// CHECK-LABEL: sil hidden [ossa] @$s4test09ConsumingB12AccepterImplV6accept6valuesyAA17NonTrivialGenericVyxGxQpn_tRvzlF :
+// CHECK:         [[ZERO:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK-NEXT:    [[ONE:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK-NEXT:    [[LENGTH:%.*]] = pack_length $Pack{repeat each T}
+// CHECK-NEXT:    br bb1([[LENGTH]])
+// CHECK:       bb1([[PREV_INDEX:%.*]] : $Builtin.Word):
+// CHECK-NEXT:    [[DONE:%.*]] = builtin "cmp_eq_Word"([[PREV_INDEX]], [[ZERO]])
+// CHECK-NEXT:    cond_br [[DONE]], bb3, bb2
+// CHECK:       bb2:
+// CHECK-NEXT:    [[INDEX:%.*]] = builtin "sub_Word"([[PREV_INDEX]], [[ONE]])
+// CHECK-NEXT:    [[PACK_INDEX:%.*]] = dynamic_pack_index [[INDEX]] of $Pack{repeat NonTrivialGeneric<each T>}
+// CHECK-NEXT:    open_pack_element [[PACK_INDEX]] of <each T> at <Pack{repeat each T}>, shape $each T, uuid [[UUID:".*"]]
+// CHECK-NEXT:    [[ARG_ADDR:%.*]] = pack_element_get [[PACK_INDEX]] of %0 as $*NonTrivialGeneric<@pack_element([[UUID]]) each T>
+// CHECK-NEXT:    destroy_addr [[ARG_ADDR]]
+// CHECK-NEXT:    br bb1([[INDEX]])
+// CHECK:       bb3:
+// CHECK-NEXT:    [[RET:%.*]] = tuple ()
+// CHECK-NEXT:    return [[RET]]
+
+//   Check that the witness thunk forwards the argument without a temporary.
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s4test09ConsumingB12AccepterImplVAA0bC0A2aDP6accept6valuesyAA17NonTrivialGenericVyqd__Gqd__Qpn_tRvd__lFTW :
+// CHECK:       bb0(%0 : $*Pack{repeat NonTrivialGeneric<each τ_0_0>}, %1 : $*ConsumingConsumingAccepterImpl):
+// CHECK-NEXT:    [[PACK:%.*]] = alloc_pack $Pack{repeat NonTrivialGeneric<each τ_0_0>}
+// CHECK-NEXT:    [[ZERO:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK-NEXT:    [[ONE:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK-NEXT:    [[LENGTH:%.*]] = pack_length $Pack{repeat each τ_0_0}
+// CHECK-NEXT:    br bb1([[ZERO]])
+// CHECK:       bb1([[INDEX:%.*]] : $Builtin.Word):
+// CHECK-NEXT:    [[DONE:%.*]] = builtin "cmp_eq_Word"([[INDEX]], [[LENGTH]])
+// CHECK-NEXT:    cond_br [[DONE]], bb3, bb2
+// CHECK:       bb2:
+// CHECK-NEXT:    [[PACK_INDEX:%.*]] = dynamic_pack_index [[INDEX]] of $Pack{repeat NonTrivialGeneric<each τ_0_0>}
+// CHECK-NEXT:    open_pack_element [[PACK_INDEX]] of <each τ_0_0> at <Pack{repeat each τ_0_0}>, shape $each τ_0_0, uuid [[UUID:".*"]]
+// CHECK-NEXT:    [[ARG_ADDR:%.*]] = pack_element_get [[PACK_INDEX]] of %0 as $*NonTrivialGeneric<@pack_element([[UUID]]) each τ_0_0>
+// CHECK-NEXT:    pack_element_set [[ARG_ADDR]] into [[PACK_INDEX]] of [[PACK]]
+// CHECK-NEXT:    [[NEXT_INDEX:%.*]] = builtin "add_Word"([[INDEX]], [[ONE]])
+// CHECK-NEXT:    br bb1([[NEXT_INDEX]])
+// CHECK:       bb3:
+// CHECK-NEXT:    load [trivial] %1
+// CHECK-NEXT:    // function_ref
+// CHECK-NEXT:    function_ref
+// CHECK-NEXT:    apply
+// CHECK-NEXT:    tuple ()
+// CHECK-NEXT:    dealloc_pack [[PACK]]
+// CHECK-NEXT:    return
+
+struct BorrowingConsumingAccepterImpl: ConsumingAccepter {
+  func accept<each T>(values: repeat NonTrivialGeneric<each T>) {}
+}
+
+//   Check that the witness thunk produces a new pack with the same contents,
+//   but that we destroy them in the thunk after the call.
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s4test30BorrowingConsumingAccepterImplVAA0cD0A2aDP6accept6valuesyAA17NonTrivialGenericVyqd__Gqd__Qpn_tRvd__lFTW :
+// CHECK:       bb0(%0 : $*Pack{repeat NonTrivialGeneric<each τ_0_0>}, %1 : $*BorrowingConsumingAccepterImpl):
+// CHECK-NEXT:    [[PACK:%.*]] = alloc_pack $Pack{repeat NonTrivialGeneric<each τ_0_0>}
+// CHECK-NEXT:    [[ZERO:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK-NEXT:    [[ONE:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK-NEXT:    [[LENGTH:%.*]] = pack_length $Pack{repeat each τ_0_0}
+// CHECK-NEXT:    br bb1([[ZERO]])
+// CHECK:       bb1([[INDEX:%.*]] : $Builtin.Word):
+// CHECK-NEXT:    [[DONE:%.*]] = builtin "cmp_eq_Word"([[INDEX]], [[LENGTH]])
+// CHECK-NEXT:    cond_br [[DONE]], bb3, bb2
+// CHECK:       bb2:
+// CHECK-NEXT:    [[PACK_INDEX:%.*]] = dynamic_pack_index [[INDEX]] of $Pack{repeat NonTrivialGeneric<each τ_0_0>}
+// CHECK-NEXT:    open_pack_element [[PACK_INDEX]] of <each τ_0_0> at <Pack{repeat each τ_0_0}>, shape $each τ_0_0, uuid [[UUID:".*"]]
+// CHECK-NEXT:    [[ARG_ADDR:%.*]] = pack_element_get [[PACK_INDEX]] of %0 as $*NonTrivialGeneric<@pack_element([[UUID]]) each τ_0_0>
+// CHECK-NEXT:    pack_element_set [[ARG_ADDR]] into [[PACK_INDEX]] of [[PACK]]
+// CHECK-NEXT:    [[NEXT_INDEX:%.*]] = builtin "add_Word"([[INDEX]], [[ONE]])
+// CHECK-NEXT:    br bb1([[NEXT_INDEX]])
+// CHECK:       bb3:
+// CHECK-NEXT:    load [trivial] %1
+// CHECK-NEXT:    // function_ref
+// CHECK-NEXT:    function_ref
+// CHECK-NEXT:    apply
+// CHECK-NEXT:    [[RET:%.*]] = tuple ()
+// CHECK-NEXT:    [[ZERO:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK-NEXT:    [[ONE:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK-NEXT:    [[LENGTH:%.*]] = pack_length $Pack{repeat each τ_0_0}
+// CHECK-NEXT:    br bb4([[LENGTH]])
+// CHECK:       bb4([[PREV_INDEX:%.*]] : $Builtin.Word):
+// CHECK-NEXT:    [[DONE:%.*]] = builtin "cmp_eq_Word"([[PREV_INDEX]], [[ZERO]])
+// CHECK-NEXT:    cond_br [[DONE]], bb6, bb5
+// CHECK:       bb5:
+// CHECK-NEXT:    [[INDEX:%.*]] = builtin "sub_Word"([[PREV_INDEX]], [[ONE]])
+// CHECK-NEXT:    [[PACK_INDEX:%.*]] = dynamic_pack_index [[INDEX]] of $Pack{repeat NonTrivialGeneric<each τ_0_0>}
+// CHECK-NEXT:    open_pack_element [[PACK_INDEX]] of <each τ_0_0> at <Pack{repeat each τ_0_0}>, shape $each τ_0_0, uuid [[UUID:".*"]]
+// CHECK-NEXT:    [[ARG_ADDR:%.*]] = pack_element_get [[PACK_INDEX]] of [[PACK]] as $*NonTrivialGeneric<@pack_element([[UUID]]) each τ_0_0>
+// CHECK-NEXT:    destroy_addr [[ARG_ADDR]]
+// CHECK-NEXT:    br bb4([[INDEX]])
+// CHECK:       bb6:
+// CHECK-NEXT:    dealloc_pack [[PACK]]
+// CHECK-NEXT:    return [[RET]]
+
+protocol BorrowingAccepter {
+  func accept<each T>(values: repeat NonTrivialGeneric<each T>)
+}
+
+struct ConsumingBorrowingAccepterImpl: BorrowingAccepter {
+  func accept<each T>(values: repeat consuming NonTrivialGeneric<each T>) {}
+}
+
+//   Check that the witness thunk copies the pack into a temporary.
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s4test30ConsumingBorrowingAccepterImplVAA0cD0A2aDP6accept6valuesyAA17NonTrivialGenericVyqd__Gqd__Qp_tRvd__lFTW :
+// CHECK:       bb0(%0 : $*Pack{repeat NonTrivialGeneric<each τ_0_0>}, %1 : $*ConsumingBorrowingAccepterImpl):
+// CHECK-NEXT:    [[PACK:%.*]] = alloc_pack $Pack{repeat NonTrivialGeneric<each τ_0_0>}
+// CHECK-NEXT:    [[TEMP_TUPLE:%.*]] = alloc_stack $(repeat NonTrivialGeneric<each τ_0_0>)
+// CHECK-NEXT:    [[ZERO:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK-NEXT:    [[ONE:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK-NEXT:    [[LENGTH:%.*]] = pack_length $Pack{repeat each τ_0_0}
+// CHECK-NEXT:    br bb1([[ZERO]])
+// CHECK:       bb1([[INDEX:%.*]] : $Builtin.Word):
+// CHECK-NEXT:    [[DONE:%.*]] = builtin "cmp_eq_Word"([[INDEX]], [[LENGTH]])
+// CHECK-NEXT:    cond_br [[DONE]], bb3, bb2
+// CHECK:       bb2:
+// CHECK-NEXT:    [[PACK_INDEX:%.*]] = dynamic_pack_index [[INDEX]] of $Pack{repeat NonTrivialGeneric<each τ_0_0>}
+// CHECK-NEXT:    open_pack_element [[PACK_INDEX]] of <each τ_0_0> at <Pack{repeat each τ_0_0}>, shape $each τ_0_0, uuid [[UUID:".*"]]
+// CHECK-NEXT:    [[TEMP_ELT_ADDR:%.*]] = tuple_pack_element_addr [[PACK_INDEX]] of [[TEMP_TUPLE]] as $*NonTrivialGeneric<@pack_element([[UUID]]) each τ_0_0>
+// CHECK-NEXT:    [[ARG_ADDR:%.*]] = pack_element_get [[PACK_INDEX]] of %0 as $*NonTrivialGeneric<@pack_element([[UUID]]) each τ_0_0>
+// CHECK-NEXT:    [[BORROW:%.*]] = load_borrow [[ARG_ADDR]]
+// CHECK-NEXT:    [[COPY:%.*]] = copy_value [[BORROW]]
+// CHECK-NEXT:    store [[COPY]] to [init] [[TEMP_ELT_ADDR]]
+// CHECK-NEXT:    pack_element_set [[TEMP_ELT_ADDR]] into [[PACK_INDEX]] of [[PACK]]
+// CHECK-NEXT:    end_borrow [[BORROW]]
+// CHECK-NEXT:    [[NEXT_INDEX:%.*]] = builtin "add_Word"([[INDEX]], [[ONE]])
+// CHECK-NEXT:    br bb1([[NEXT_INDEX]])
+// CHECK:       bb3:
+// CHECK-NEXT:    load [trivial] %1
+// CHECK-NEXT:    // function_ref
+// CHECK-NEXT:    function_ref
+// CHECK-NEXT:    apply
+// CHECK-NEXT:    tuple ()
+// CHECK-NEXT:    dealloc_stack [[TEMP_TUPLE]]
+// CHECK-NEXT:    dealloc_pack [[PACK]]
+// CHECK-NEXT:    return
diff --git a/test/SILGen/protocol_resilience.swift b/test/SILGen/protocol_resilience.swift
index 0cc216e14748f..88d920fb41988 100644
--- a/test/SILGen/protocol_resilience.swift
+++ b/test/SILGen/protocol_resilience.swift
@@ -259,6 +259,15 @@ public protocol ResilientAssocTypes {
   associatedtype AssocType: P = ConformsToP
 }
 
+// rdar://155798849 - This is a pointless protocol and conformance but it shouldn't crash
+public protocol SillyP: SillyC {
+  func f()
+}
+
+public class SillyC: SillyP {
+  public func f() {}
+}
+
 // CHECK-LABEL: sil_default_witness_table P {
 // CHECK-NEXT: }
 
diff --git a/test/SILGen/read_requirements.swift b/test/SILGen/read_requirements.swift
index dee6d8bb78815..d9efa065f34e8 100644
--- a/test/SILGen/read_requirements.swift
+++ b/test/SILGen/read_requirements.swift
@@ -1,11 +1,13 @@
-// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types                           \
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types   \
 // RUN:     %s                                              \
+// RUN:     -enable-callee-allocated-coro-abi               \
 // RUN:     -enable-library-evolution                       \
 // RUN:     -enable-experimental-feature CoroutineAccessors \
 // RUN: | %FileCheck %s --check-prefixes=CHECK,CHECK-NORMAL,CHECK-%target-abi-stability
 
-// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types                                              \
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types                      \
 // RUN:     %s                                                                 \
+// RUN:     -enable-callee-allocated-coro-abi                                  \
 // RUN:     -enable-library-evolution                                          \
 // RUN:     -enable-experimental-feature CoroutineAccessors                    \
 // RUN:     -enable-experimental-feature CoroutineAccessorsUnwindOnCallerError \
@@ -31,7 +33,7 @@ public struct U : ~Copyable {}
 public protocol P1 : ~Copyable {
   @_borrowed
   var ubgs: U { get set }
-// CHECK-LABEL sil [ossa] @$s17read_requirements2P1P4ubgsAA1UVvy : {{.*}} {
+// CHECK-LABEL: sil {{.*}} [ossa] @$s17read_requirements2P1P4ubgsAA1UVvy : {{.*}} {
 // CHECK:      bb0(
 // CHECK-SAME:     [[SELF_UNCHECKED:%[^:]+]]
 // CHECK-SAME: ):
diff --git a/test/SILGen/reference_bindings.swift b/test/SILGen/reference_bindings.swift
index c45b51ef27768..385c3ae1037f2 100644
--- a/test/SILGen/reference_bindings.swift
+++ b/test/SILGen/reference_bindings.swift
@@ -35,10 +35,10 @@ func doSomething() {}
 // SIL:   [[BOX:%.*]] = alloc_stack [var_decl] $Int, var, name "x"
 // SIL:   [[INOUT_BOX:%.*]] = alloc_stack [var_decl] $Int, var, name "x2"
 // SIL:   [[ACCESS:%.*]] = begin_access [modify] [static] [[BOX]]
-// SIL:   copy_addr [take] [[ACCESS]] to [init] [[INOUT_BOX]]
+// SIL:   store {{%.*}} to [[INOUT_BOX]]
 // SIL:   [[FUNC:%.*]] = function_ref @$s18reference_bindings11doSomethingyyF : $@convention(thin) () -> ()
 // SIL:   apply [[FUNC]]()
-// SIL:   copy_addr [take] [[INOUT_BOX]] to [init] [[ACCESS]]
+// SIL:   store {{%.*}} to [[ACCESS]]
 // SIL:   end_access [[ACCESS]]
 // SIL: } // end sil function '$s18reference_bindings13testBindToVaryyF'
 func testBindToVar() {
diff --git a/test/SILGen/resilient_assign_by_wrapper.swift b/test/SILGen/resilient_assign_by_wrapper.swift
deleted file mode 100644
index bebf7154d4683..0000000000000
--- a/test/SILGen/resilient_assign_by_wrapper.swift
+++ /dev/null
@@ -1,103 +0,0 @@
-// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types %s -emit-verbose-sil -enable-library-evolution | %FileCheck %s
-
-@propertyWrapper
-public struct WrapGod<T> {
-  private var value: T
-
-  public init(wrappedValue: T) {
-    value = wrappedValue
-  }
-
-  public var wrappedValue: T {
-    get { value }
-    set { value = newValue }
-  }
-}
-
-public protocol Existential {}
-
-public enum AddressOnlyEnum {
-  case some
-  case value(Existential?)
-}
-
-public class AddressOnlySetter {
-  @WrapGod var value: AddressOnlyEnum = .value(nil)
-
-  init() {
-    // CHECK-LABEL: sil hidden [ossa] @$s27resilient_assign_by_wrapper17AddressOnlySetterCACycfc
-    // CHECK: [[E1:%.*]] = alloc_stack $AddressOnlyEnum
-    // CHECK: [[W:%.*]] = alloc_stack $WrapGod<AddressOnlyEnum>
-    // CHECK: [[I:%.*]] = function_ref @$s27resilient_assign_by_wrapper17AddressOnlySetterC5valueAA0eF4EnumOvpfP : $@convention(thin) (@in AddressOnlyEnum) -> @out WrapGod<AddressOnlyEnum>
-    // CHECK: apply [[I]]([[W]], [[E1]])
-
-    // CHECK: [[E2:%.*]] = alloc_stack $AddressOnlyEnum
-    // CHECK-NEXT: inject_enum_addr [[E2]] : $*AddressOnlyEnum, #AddressOnlyEnum.some!enumelt
-    // CHECK: [[S:%.*]] = partial_apply [callee_guaranteed] [on_stack] {{%.*}}({{%.*}}) : $@convention(method) (@in AddressOnlyEnum, @guaranteed AddressOnlySetter) -> ()
-    // CHECK: assign_by_wrapper [[E2]] : $*AddressOnlyEnum
-    // CHECK-SAME: set [[S]] : $@noescape @callee_guaranteed (@in AddressOnlyEnum) -> ()
-    self.value = .some
-  }
-
-  func testAssignment() {
-    // CHECK-LABEL: sil hidden [ossa] @$s27resilient_assign_by_wrapper17AddressOnlySetterC14testAssignmentyyF
-    // CHECK: [[E:%.*]] = alloc_stack $AddressOnlyEnum
-    // CHECK: inject_enum_addr [[E]] : $*AddressOnlyEnum, #AddressOnlyEnum.some!enumelt
-    // CHECK: [[S:%.*]] = class_method %0 : $AddressOnlySetter, #AddressOnlySetter.value!setter : (AddressOnlySetter) -> (AddressOnlyEnum) -> (), $@convention(method) (@in AddressOnlyEnum, @guaranteed AddressOnlySetter) -> ()
-    // CHECK: apply [[S]]([[E]], %0) : $@convention(method) (@in AddressOnlyEnum, @guaranteed AddressOnlySetter) -> ()
-    self.value = .some
-  }
-}
-
-public struct SubstitutedSetter<T> {
-  @WrapGod var value: T
-}
-
-extension SubstitutedSetter where T == Bool {
-  init() {
-    // CHECK-LABEL: hidden [ossa] @$s27resilient_assign_by_wrapper17SubstitutedSetterVAASbRszlEACySbGycfC
-    // CHECK: [[W:%.*]] = struct_element_addr {{%.*}} : $*SubstitutedSetter<Bool>, #SubstitutedSetter._value
-    // CHECK: [[B:%.*]] = alloc_stack $Bool
-    // CHECK: assign_by_wrapper [[B]] : $*Bool to [[W]] : $*WrapGod<Bool>
-    // CHECK-SAME: init {{%.*}} : $@callee_guaranteed (@in Bool) -> @out WrapGod<Bool>
-    // CHECK-SAME: set {{%.*}} : $@noescape @callee_guaranteed (@in Bool) -> ()
-    self.value = true
-  }
-}
-
-public struct ReabstractedSetter<T> {
-  @WrapGod var value: (T) -> ()
-}
-
-extension ReabstractedSetter where T == Int {
-  init() {
-    // CHECK-LABEL: hidden [ossa] @$s27resilient_assign_by_wrapper18ReabstractedSetterVAASiRszlEACySiGycfC
-    // CHECK: [[F:%.*]] = function_ref @$s27resilient_assign_by_wrapper18ReabstractedSetterVAASiRszlEACySiGycfcySicfU_ : $@convention(thin) (Int) -> ()
-    // CHECK: [[TH_F:%.*]] = thin_to_thick_function [[F]] : $@convention(thin) (Int) -> () to $@callee_guaranteed (Int) -> ()
-    // CHECK: [[THUNK_REF:%.*]] = function_ref @$sSiIegy_SiIegn_TR : $@convention(thin) (@in_guaranteed Int, @guaranteed @callee_guaranteed (Int) -> ()) -> ()
-    // CHECK: [[CF:%.*]] = partial_apply [callee_guaranteed] [[THUNK_REF]]([[TH_F]]) : $@convention(thin) (@in_guaranteed Int, @guaranteed @callee_guaranteed (Int) -> ()) -> ()
-    // CHECK: [[CF2:%.*]] = convert_function [[CF]]
-    // CHECK: assign_by_wrapper [[CF2]]
-    // CHECK-SAME: to {{%.*}} : $*WrapGod<(Int) -> ()>
-    self.value = { x in }
-  }
-}
-
-public struct ObjectifiedSetter<T: AnyObject> {
-  @WrapGod var value: T
-}
-
-public class SomeObject {}
-
-extension ObjectifiedSetter where T == SomeObject {
-  init() {
-    // CHECK-LABEL: sil hidden [ossa] @$s27resilient_assign_by_wrapper17ObjectifiedSetterV5valuexvs : $@convention(method) <T where T : AnyObject> (@owned T, @inout ObjectifiedSetter<T>) -> () {
-    // CHECK: [[OBJ:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick SomeObject.Type) -> @owned SomeObject
-    // CHECK: [[STORAGE:%.*]] = struct_element_addr {{%.*}} : $*ObjectifiedSetter<SomeObject>, #ObjectifiedSetter._value
-    // CHECK: assign_by_wrapper [[OBJ]] : $SomeObject to [[STORAGE]] : $*WrapGod<SomeObject>
-    // CHECK-SAME: init {{%.*}} : $@callee_guaranteed (@owned SomeObject) -> @out WrapGod<SomeObject>
-    // CHECK-SAME: set {{%.*}} : $@noescape @callee_guaranteed (@owned SomeObject) -> ()
-    self.value = SomeObject()
-  }
-}
-
diff --git a/test/SILGen/resilient_assign_or_init.swift b/test/SILGen/resilient_assign_or_init.swift
new file mode 100644
index 0000000000000..6661938b2c428
--- /dev/null
+++ b/test/SILGen/resilient_assign_or_init.swift
@@ -0,0 +1,101 @@
+// RUN: %target-swift-emit-silgen -Xllvm -sil-print-types %s -emit-verbose-sil -enable-library-evolution | %FileCheck %s
+
+@propertyWrapper
+public struct WrapGod<T> {
+  private var value: T
+
+  public init(wrappedValue: T) {
+    value = wrappedValue
+  }
+
+  public var wrappedValue: T {
+    get { value }
+    set { value = newValue }
+  }
+}
+
+public protocol Existential {}
+
+public enum AddressOnlyEnum {
+  case some
+  case value(Existential?)
+}
+
+public class AddressOnlySetter {
+  @WrapGod var value: AddressOnlyEnum = .value(nil)
+
+  init() {
+    // CHECK-LABEL: sil hidden [ossa] @$s24resilient_assign_or_init17AddressOnlySetterCACycfc
+    // CHECK: [[E1:%.*]] = alloc_stack $AddressOnlyEnum
+    // CHECK: [[W:%.*]] = alloc_stack $WrapGod<AddressOnlyEnum>
+    // property wrapper backing initializer of AddressOnlySetter.value
+    // CHECK: [[I:%.*]] = function_ref @$s24resilient_assign_or_init17AddressOnlySetterC5valueAA0eF4EnumOvpfP : $@convention(thin) (@in AddressOnlyEnum) -> @out WrapGod<AddressOnlyEnum>
+    // CHECK: apply [[I]]([[W]], [[E1]])
+
+    // CHECK: [[E2:%.*]] = alloc_stack $AddressOnlyEnum
+    // CHECK-NEXT: inject_enum_addr [[E2]] : $*AddressOnlyEnum, #AddressOnlyEnum.some!enumelt
+    // CHECK: [[S:%.*]] = partial_apply [callee_guaranteed] [on_stack] {{%.*}}({{%.*}}) : $@convention(method) (@in AddressOnlyEnum, @guaranteed AddressOnlySetter) -> ()
+    // CHECK: assign_or_init #AddressOnlySetter.value, self {{%.*}} : $AddressOnlySetter, value [[E2]] : $*AddressOnlyEnum
+    // CHECK-SAME: set [[S]] : $@noescape @callee_guaranteed (@in AddressOnlyEnum) -> ()
+    self.value = .some
+  }
+
+  func testAssignment() {
+    // CHECK-LABEL: sil hidden [ossa] @$s24resilient_assign_or_init17AddressOnlySetterC14testAssignmentyyF
+    // CHECK: [[E:%.*]] = alloc_stack $AddressOnlyEnum
+    // CHECK: inject_enum_addr [[E]] : $*AddressOnlyEnum, #AddressOnlyEnum.some!enumelt
+    // CHECK: [[S:%.*]] = class_method %0 : $AddressOnlySetter, #AddressOnlySetter.value!setter : (AddressOnlySetter) -> (AddressOnlyEnum) -> (), $@convention(method) (@in AddressOnlyEnum, @guaranteed AddressOnlySetter) -> ()
+    // CHECK: apply [[S]]([[E]], %0) : $@convention(method) (@in AddressOnlyEnum, @guaranteed AddressOnlySetter) -> ()
+    self.value = .some
+  }
+}
+
+public struct SubstitutedSetter<T> {
+  @WrapGod var value: T
+}
+
+extension SubstitutedSetter where T == Bool {
+  init() {
+    // CHECK-LABEL: hidden [ossa] @$s24resilient_assign_or_init17SubstitutedSetterVAASbRszlEACySbGycfC
+    // CHECK: [[B:%.*]] = alloc_stack $Bool
+    // CHECK: assign_or_init #SubstitutedSetter.value, self {{%.*}} : $*SubstitutedSetter<Bool>, value [[B]] : $*Bool
+    // CHECK-SAME: init {{%.*}} : $@callee_guaranteed (@in Bool) -> @out WrapGod<Bool>
+    // CHECK-SAME: set {{%.*}} : $@noescape @callee_guaranteed (@in Bool) -> ()
+    self.value = true
+  }
+}
+
+public struct ReabstractedSetter<T> {
+  @WrapGod var value: (T) -> ()
+}
+
+extension ReabstractedSetter where T == Int {
+  init() {
+    // CHECK-LABEL: hidden [ossa] @$s24resilient_assign_or_init18ReabstractedSetterVAASiRszlEACySiGycfC
+    // CHECK: [[F:%.*]] = function_ref @$s24resilient_assign_or_init18ReabstractedSetterVAASiRszlEACySiGycfcySicfU_ : $@convention(thin) (Int) -> ()
+    // CHECK: [[TH_F:%.*]] = thin_to_thick_function [[F]] : $@convention(thin) (Int) -> () to $@callee_guaranteed (Int) -> ()
+    // CHECK: [[THUNK_REF:%.*]] = function_ref @$sSiIegy_SiIegn_TR : $@convention(thin) (@in_guaranteed Int, @guaranteed @callee_guaranteed (Int) -> ()) -> ()
+    // CHECK: [[CF:%.*]] = partial_apply [callee_guaranteed] [[THUNK_REF]]([[TH_F]]) : $@convention(thin) (@in_guaranteed Int, @guaranteed @callee_guaranteed (Int) -> ()) -> ()
+    // CHECK: [[CF2:%.*]] = convert_function [[CF]]
+    // CHECK: assign_or_init #ReabstractedSetter.value, self {{%.*}} : $*ReabstractedSetter<Int>, value [[CF2]]
+    self.value = { x in }
+  }
+}
+
+public struct ObjectifiedSetter<T: AnyObject> {
+  @WrapGod var value: T
+}
+
+public class SomeObject {}
+
+extension ObjectifiedSetter where T == SomeObject {
+  init() {
+    // CHECK-LABEL: sil hidden [ossa] @$s24resilient_assign_or_init17ObjectifiedSetterV5valuexvs : $@convention(method) <T where T : AnyObject> (@owned T, @inout ObjectifiedSetter<T>) -> () {
+    // CHECK: [[OBJ:%.*]] = apply {{%.*}}({{%.*}}) : $@convention(method) (@thick SomeObject.Type) -> @owned SomeObject
+    // CHECK: assign_or_init #ObjectifiedSetter.value, self {{%.*}} : $*ObjectifiedSetter<SomeObject>, value [[OBJ]]
+    // CHECK-SAME: init {{%.*}} : $@callee_guaranteed (@owned SomeObject) -> @out WrapGod<SomeObject>
+    // CHECK-SAME: set {{%.*}} : $@noescape @callee_guaranteed (@owned SomeObject) -> ()
+    self.value = SomeObject()
+  }
+}
+
diff --git a/test/SILGen/specialize_attr.swift b/test/SILGen/specialize_attr.swift
index 3fb19f220c708..98c27788b4de7 100644
--- a/test/SILGen/specialize_attr.swift
+++ b/test/SILGen/specialize_attr.swift
@@ -3,6 +3,7 @@
 // RUN: %target-swift-frontend -module-name A -emit-module-path %t/A.swiftmodule -enable-library-evolution -swift-version 5 %S/Inputs/specialize_attr_module.swift
 // RUN: %target-swift-frontend -I %t -module-name B -emit-module-path %t/B.swiftmodule -enable-library-evolution -swift-version 5 %S/Inputs/specialize_attr_module2.swift
 // RUN: %target-swift-emit-silgen -I %t -module-name specialize_attr -emit-verbose-sil %s -swift-version 5 | %FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-%target-os
+// RUN: %target-swift-emit-silgen -I %t -module-name specialize_attr -emit-verbose-sil %s -swift-version 5 | %FileCheck %s -check-prefix=CHECK2
 // RUN: %target-swift-emit-sil -I %t -sil-verify-all -O -module-name specialize_attr -emit-verbose-sil %s | %FileCheck -check-prefix=CHECK-OPT -check-prefix=CHECK-OPT-EVO -check-prefix=CHECK-OPT-%target-os %s
 
 // Test .swiftinterface
@@ -342,3 +343,24 @@ extension InternalThing2 {
     }
   }
 }
+
+
+// Tests for the "public" @specialized attribute.
+// CHECK2: @specialized(where T == Int, U == Float)
+// CHECK2-NEXT: @specialized(where T == Klass1, U == FakeString)
+// CHECK2-NEXT: func publicSpecializeThis<T, U>(_ t: T, u: U)
+@specialized(where T == Int, U == Float)
+@specialized(where T == Klass1, U == FakeString)
+public func publicSpecializeThis<T, U>(_ t: T, u: U) {}
+// CHECK2: extension TestPrespecialized {
+// CHECK2-NEXT:   @specialized(where T == Int)
+// CHECK2-NEXT:   public func testExtension()
+
+extension TestPrespecialized {
+    @specialized(where T == Int)
+    public func testExtension() {
+    }
+}
+
+// CHECK2: sil [_specialize exported: false, kind: full, where T == Klass1, U == FakeString] [_specialize exported: false, kind: full, where T == Int, U == Float] [ossa] @$s15specialize_attr20publicSpecializeThis_1uyx_q_tr0_lF
+// CHECK2: sil [_specialize exported: false, kind: full, where T == Int] [ossa] @$s15specialize_attr18TestPrespecializedV13testExtensionyyF
diff --git a/test/SILGen/statements.swift b/test/SILGen/statements.swift
index b9b3882da5c88..496e1c309cfd4 100644
--- a/test/SILGen/statements.swift
+++ b/test/SILGen/statements.swift
@@ -168,7 +168,7 @@ func for_loops2() {
   // CHECK: alloc_stack $Optional<MyClass>
   // CHECK-NEXT: [[WRITE:%.*]] = begin_access [modify] [unknown]
   // CHECK: [[NEXT:%[0-9]+]] = function_ref @$ss16IndexingIteratorV4next7ElementQzSgyF : $@convention(method) <τ_0_0 where τ_0_0 : Collection> (@inout IndexingIterator<τ_0_0>) -> @out Optional<τ_0_0.Element>
-  // CHECK-NEXT: apply [[NEXT]]<[MyClass]>
+  // CHECK-NEXT: apply [[NEXT]]<Array<MyClass>>
   let objects = [MyClass(), MyClass() ]
   for obj in objects {
     obj.foo()
diff --git a/test/SILGen/subst_function_type_opaque.swift b/test/SILGen/subst_function_type_opaque.swift
new file mode 100644
index 0000000000000..eaa7483cf4207
--- /dev/null
+++ b/test/SILGen/subst_function_type_opaque.swift
@@ -0,0 +1,23 @@
+// RUN: %target-swift-emit-silgen %s
+
+public protocol P {}
+
+extension P {
+}
+
+public struct S: P {
+  public func callAsFunction<V>(_: () -> V) { }
+}
+
+public func f() -> some P {
+  S()
+}
+
+public struct G<T: P>: P {
+  public init(_: () -> T) {}
+}
+
+S() {
+  return G { return f() }
+}
+
diff --git a/test/SILGen/switch_noncopyable_consumed_subject_with_open_existential.swift b/test/SILGen/switch_noncopyable_consumed_subject_with_open_existential.swift
new file mode 100644
index 0000000000000..30f381d85a8b9
--- /dev/null
+++ b/test/SILGen/switch_noncopyable_consumed_subject_with_open_existential.swift
@@ -0,0 +1,17 @@
+// RUN: %target-swift-emit-silgen -verify %s
+
+func fooify(p: any P) {
+  switch p.foo() {
+  case .success:
+    break
+  }
+}
+
+enum Resoult: ~Copyable {
+  case success
+}
+
+protocol P {
+  func foo() -> Resoult
+}
+
diff --git a/test/SILGen/synthesized_conformance_class.swift b/test/SILGen/synthesized_conformance_class.swift
index b4b0608abc9e3..098dab5194527 100644
--- a/test/SILGen/synthesized_conformance_class.swift
+++ b/test/SILGen/synthesized_conformance_class.swift
@@ -56,7 +56,7 @@ class Nonfinal<T> {
 
 // CHECK-LABEL: sil private [ossa] @$s29synthesized_conformance_class5FinalC10CodingKeys{{.*}}11stringValueAFyx_GSgSS_tcfC : $@convention(method) <T> (@owned String, @thin Final<T>.CodingKeys.Type) -> Optional<Final<T>.CodingKeys> {
 // CHECK-LABEL: sil private [ossa] @$s29synthesized_conformance_class5FinalC10CodingKeys{{.*}}8intValueAFyx_GSgSi_tcfC : $@convention(method) <T> (Int, @thin Final<T>.CodingKeys.Type) -> Optional<Final<T>.CodingKeys> {
-// CHECK-LABEL: sil private [ossa] @$s29synthesized_conformance_class5FinalC10CodingKeys{{.*}}21__derived_enum_equalsySbAFyx_G_AHtFZ : $@convention(method) <T> (Final<T>.CodingKeys, Final<T>.CodingKeys, @thin Final<T>.CodingKeys.Type) -> Bool {
+// CHECK-LABEL: sil private [_semantics "derived_enum_equals"] [ossa] @$s29synthesized_conformance_class5FinalC10CodingKeys{{.*}}21__derived_enum_equalsySbAFyx_G_AHtFZ : $@convention(method) <T> (Final<T>.CodingKeys, Final<T>.CodingKeys, @thin Final<T>.CodingKeys.Type) -> Bool {
 // CHECK-LABEL: sil private [ossa] @$s29synthesized_conformance_class5FinalC10CodingKeys{{.*}}4hash4intoys6HasherVz_tF : $@convention(method) <T> (@inout Hasher, Final<T>.CodingKeys) -> () {
 // CHECK-LABEL: sil private [ossa] @$s29synthesized_conformance_class5FinalC10CodingKeys{{.*}}9hashValueSivg : $@convention(method) <T> (Final<T>.CodingKeys) -> Int {
 // CHECK-LABEL: sil private [ossa] @$s29synthesized_conformance_class5FinalC10CodingKeys{{.*}}8intValueSiSgvg : $@convention(method) <T> (Final<T>.CodingKeys) -> Optional<Int> {
diff --git a/test/SILGen/synthesized_conformance_enum.swift b/test/SILGen/synthesized_conformance_enum.swift
index ed52b0bb8e5ae..fd76e790a04c4 100644
--- a/test/SILGen/synthesized_conformance_enum.swift
+++ b/test/SILGen/synthesized_conformance_enum.swift
@@ -37,7 +37,7 @@ enum NoValues {
 extension Enum: Equatable where T: Equatable {}
 // CHECK-FRAGILE-LABEL: // static Enum<A>.__derived_enum_equals(_:_:)
 // CHECK-FRAGILE-NEXT: // Isolation: unspecified
-// CHECK-FRAGILE-NEXT: sil hidden [ossa] @$s28synthesized_conformance_enum4EnumOAASQRzlE010__derived_C7_equalsySbACyxG_AEtFZ : $@convention(method) <T where T : Equatable> (@in_guaranteed Enum<T>, @in_guaranteed Enum<T>, @thin Enum<T>.Type) -> Bool {
+// CHECK-FRAGILE-NEXT: sil hidden [_semantics "derived_enum_equals"] [ossa] @$s28synthesized_conformance_enum4EnumOAASQRzlE010__derived_C7_equalsySbACyxG_AEtFZ : $@convention(method) <T where T : Equatable> (@in_guaranteed Enum<T>, @in_guaranteed Enum<T>, @thin Enum<T>.Type) -> Bool {
 // CHECK-RESILIENT-LABEL: // static Enum<A>.== infix(_:_:)
 // CHECK-RESILIENT-NEXT: // Isolation: unspecified
 // CHECK-RESILIENT-NEXT: sil hidden [ossa] @$s28synthesized_conformance_enum4EnumOAASQRzlE2eeoiySbACyxG_AEtFZ : $@convention(method) <T where T : Equatable> (@in_guaranteed Enum<T>, @in_guaranteed Enum<T>, @thin Enum<T>.Type) -> Bool {
diff --git a/test/SILGen/toplevel_globalactorvars.swift b/test/SILGen/toplevel_globalactorvars.swift
index 77f81c6c8af51..5cde7c24fc169 100644
--- a/test/SILGen/toplevel_globalactorvars.swift
+++ b/test/SILGen/toplevel_globalactorvars.swift
@@ -3,10 +3,14 @@
 // a
 // CHECK-LABEL: sil_global hidden @$s24toplevel_globalactorvars1aSivp : $Int
 
-// CHECK-LABEL: sil private [ossa] @async_Main
+// CHECK-LABEL: sil private [ossa] @async_Main : $@convention(thin) @async () -> () {
 // CHECK: bb0:
-// CHECK-NEXT: [[MAIN:%.*]] = builtin "buildMainActorExecutorRef"() : $Builtin.Executor
-// CHECK-NEXT: [[MAIN_OPTIONAL:%[0-9]+]] = enum $Optional<Builtin.Executor>, #Optional.some!enumelt, [[MAIN]]
+// CHECK: [[META:%.*]] = metatype $@thick MainActor.Type
+// CHECK: [[FUNC:%.*]] = function_ref @$sScM6sharedScMvgZ : $@convention(method) (@thick MainActor.Type) -> @owned MainActor
+// CHECK: [[ACTOR_RAW:%.*]] = apply [[FUNC]]([[META]])
+// CHECK: [[ACTOR_RAW_E:%.*]] = init_existential_ref [[ACTOR_RAW]]
+// CHECK: [[ACTOR_RAW_E_O:%.*]] = enum $Optional<any Actor>, #Optional.some!enumelt, [[ACTOR_RAW_E]]
+// CHECK: [[ACTOR:%.*]] = begin_borrow [[ACTOR_RAW_E_O]]
 
 actor MyActorImpl {}
 
@@ -67,7 +71,7 @@ await printFromMyActor(value: a)
 // CHECK: hop_to_executor [[ACTORREF]] : $MyActorImpl
 // CHECK: end_borrow [[ACTORREF]]
 // CHECK: {{%[0-9]+}} = apply [[PRINTFROMMYACTOR_FUNC]]([[AGLOBAL]])
-// CHECK: hop_to_executor [[MAIN_OPTIONAL]]
+// CHECK: hop_to_executor [[ACTOR]]
 
 if a < 10 {
 // CHECK: [[AACCESS:%[0-9]+]] = begin_access [read] [dynamic] [[AREF]] : $*Int
@@ -121,5 +125,12 @@ if a < 10 {
     // CHECK: hop_to_executor [[ACTORREF]] : $MyActorImpl
     // CHECK: end_borrow [[ACTORREF]]
     // CHECK: {{%[0-9]+}} = apply [[PRINTFROMMYACTOR_FUNC]]([[AGLOBAL]])
-    // CHECK: hop_to_executor [[MAIN_OPTIONAL]]
+    // CHECK: hop_to_executor [[ACTOR]]
 }
+
+nonisolated(nonsending) func nonisolatedNonSendingFunction() async {}
+
+// CHECK: [[FUNC:%.*]] = function_ref @$s24toplevel_globalactorvars29nonisolatedNonSendingFunctionyyYaF : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+// CHECK: apply [[FUNC]]([[ACTOR]])
+// CHECK-NEXT: hop_to_executor [[ACTOR]]
+await nonisolatedNonSendingFunction()
diff --git a/test/SILGen/trivial_address_only_switch.swift b/test/SILGen/trivial_address_only_switch.swift
new file mode 100644
index 0000000000000..8a272250b809c
--- /dev/null
+++ b/test/SILGen/trivial_address_only_switch.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-emit-silgen -verify -disable-availability-checking %s
+
+public enum StreamYieldResult<let count: Int>: Sendable {
+    case literal(buffer: InlineArray<count, UInt8>)
+    case end(buffer: InlineArray<count, UInt8>, endIndex: Int)
+    
+    public func buffer() -> InlineArray<count, UInt8> {
+        switch self {
+        case .literal(let b):
+            return b
+        case .end(let b, _):
+            return b
+        }
+    }
+}
diff --git a/test/SILGen/tuple_element_projection.swift b/test/SILGen/tuple_element_projection.swift
new file mode 100644
index 0000000000000..fad7434dde829
--- /dev/null
+++ b/test/SILGen/tuple_element_projection.swift
@@ -0,0 +1,43 @@
+// RUN: %target-swift-emit-silgen -module-name test %s | %FileCheck %s
+
+func returnStringAnyPair() -> (String, Any) {
+  return ("hello", "world")
+}
+
+//   Test that we handle projections appropriately in emit-into contexts.
+// CHECK-LABEL: sil hidden [ossa] @$s4test0A17ProjectIntoReturnypyF :
+// CHECK:       bb0(%0 : $*Any):
+// CHECK-NEXT:    // function_ref
+// CHECK-NEXT:    [[FN:%.*]] = function_ref @$s4test19returnStringAnyPairSS_yptyF :
+// CHECK-NEXT:    [[STRING:%.*]] = apply [[FN]](%0)
+// CHECK-NEXT:    ignored_use [[STRING]]
+// CHECK-NEXT:    destroy_value [[STRING]]
+// CHECK-NEXT:    [[RET:%.*]] = tuple ()
+// CHECK-NEXT:    return [[RET]]
+func testProjectIntoReturn() -> Any {
+  return returnStringAnyPair().1
+}
+
+func returnAsTuple<each T>(_ args: repeat each T) -> (repeat each T) {
+  (repeat each args)
+}
+
+//   Test that we handle projections of non-pack elements of tuples.
+// CHECK-LABEL: sil hidden [ossa] @$s4test0A14PackProjectionySSxxQpRvzlF :
+// CHECK:       bb0(%0 : $*Pack{repeat each T}):
+// CHECK:         [[VALUES:%.*]] = alloc_stack [lexical] [var_decl] $(String, repeat each T, String)
+//   The result gets expanded, so we emit a pack loop to set up a pack
+//   initialization of the elements of values. Eventually we do this call:
+// CHECK:         [[FN:%.*]] = function_ref @$s4test13returnAsTupleyxxQp_txxQpRvzlF :
+// CHECK-NEXT:    apply [[FN]]<Pack{String, repeat each T, String}>(
+//   This copy is unnecessary.
+// CHECK:         [[TEMP:%.*]] = alloc_stack $(String, repeat each T, String)
+// CHECK-NEXT:    copy_addr [[VALUES]] to [init] [[TEMP]]
+// CHECK:         [[INDEX2:%.*]] = scalar_pack_index 2 of
+// CHECK-NEXT:    [[ELT2_ADDR:%.*]] = tuple_pack_element_addr [[INDEX2]] of [[TEMP]] as $*String
+// CHECK-NEXT:    [[VALUE:%.*]] = load [take] [[ELT2_ADDR]]
+// CHECK:         return [[VALUE]]
+func testPackProjection<each T>(_ args: repeat each T) -> String {
+  let values = returnAsTuple("start", repeat each args, "end")
+  return values.2
+}
diff --git a/test/SILGen/typed_throws_async.swift b/test/SILGen/typed_throws_async.swift
new file mode 100644
index 0000000000000..23e600ae68dd9
--- /dev/null
+++ b/test/SILGen/typed_throws_async.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-emit-silgen %s
+
+enum CustomError: Error {
+    case error
+}
+
+struct Test2<T> {
+    init(_: T) async throws(CustomError) {}
+}
+
+do {
+    _ = try await Test2(1)
+} catch {
+    print("\(error)")
+}
diff --git a/test/SILGen/typed_throws_generic.swift b/test/SILGen/typed_throws_generic.swift
index 9a91a9130f0bf..7f5ae94cb2ba1 100644
--- a/test/SILGen/typed_throws_generic.swift
+++ b/test/SILGen/typed_throws_generic.swift
@@ -387,3 +387,10 @@ extension ReducedError where T == MyError {
     throw MyError.fail
   }
 }
+
+// https://github.com/swiftlang/swift/issues/74289
+struct LoadableGeneric<E>: Error {}
+
+func throwsLoadableGeneric<E>(_: E) throws(LoadableGeneric<E>) {
+  throw LoadableGeneric<E>()
+}
diff --git a/test/SILGen/unavailable_decl_custom_domain.swift b/test/SILGen/unavailable_decl_custom_domain.swift
index 5db167fde9095..abf1572e378b2 100644
--- a/test/SILGen/unavailable_decl_custom_domain.swift
+++ b/test/SILGen/unavailable_decl_custom_domain.swift
@@ -1,25 +1,19 @@
 // RUN: %target-swift-emit-silgen -module-name Test %s -verify \
 // RUN:   -enable-experimental-feature CustomAvailability \
 // RUN:   -define-enabled-availability-domain EnabledDomain \
+// RUN:   -define-always-enabled-availability-domain AlwaysEnabledDomain \
 // RUN:   -define-disabled-availability-domain DisabledDomain \
 // RUN:   -define-dynamic-availability-domain DynamicDomain \
-// RUN:   | %FileCheck %s --check-prefixes=CHECK
-
-// RUN: %target-swift-emit-silgen -module-name Test %s -verify \
-// RUN:   -enable-experimental-feature CustomAvailability \
-// RUN:   -define-enabled-availability-domain EnabledDomain \
-// RUN:   -define-disabled-availability-domain DisabledDomain \
-// RUN:   -define-dynamic-availability-domain DynamicDomain \
-// RUN:   -unavailable-decl-optimization=stub \
-// RUN:   | %FileCheck %s --check-prefixes=CHECK
+// RUN:   | %FileCheck %s --check-prefixes=CHECK,CHECK-NOOPT
 
 // RUN: %target-swift-emit-silgen -module-name Test %s -verify \
 // RUN:   -enable-experimental-feature CustomAvailability \
 // RUN:   -define-enabled-availability-domain EnabledDomain \
+// RUN:   -define-always-enabled-availability-domain AlwaysEnabledDomain \
 // RUN:   -define-disabled-availability-domain DisabledDomain \
 // RUN:   -define-dynamic-availability-domain DynamicDomain \
 // RUN:   -unavailable-decl-optimization=complete \
-// RUN:   | %FileCheck %s --check-prefixes=CHECK
+// RUN:   | %FileCheck %s --check-prefixes=CHECK,CHECK-OPT
 
 // REQUIRES: swift_feature_CustomAvailability
 
@@ -34,6 +28,14 @@ public func availableInEnabledDomain() { }
 @available(EnabledDomain, unavailable)
 public func unavailableInEnabledDomain() { }
 
+// CHECK: s4Test30availableInAlwaysEnabledDomainyyF
+@available(AlwaysEnabledDomain)
+public func availableInAlwaysEnabledDomain() { }
+
+// CHECK-NOT: s4Test32unavailableInAlwaysEnabledDomainyyF
+@available(AlwaysEnabledDomain, unavailable)
+public func unavailableInAlwaysEnabledDomain() { }
+
 // CHECK-NOT: s4Test25availableInDisabledDomainyyF
 @available(DisabledDomain)
 public func availableInDisabledDomain() { }
@@ -85,41 +87,24 @@ public func availableInEnabledAndDisabledDomain() { }
 @available(EnabledDomain)
 public func availableInDisabledAndEnabledDomain() { }
 
-// CHECK-LABEL: sil{{.*}}$s4Test28testIfAvailableEnabledDomainyyF : $@convention(thin) () -> ()
-public func testIfAvailableEnabledDomain() {
-  // CHECK: bb0:
-  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, -1
-  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
-
-  // CHECK: [[TRUE_BB]]:
-  // CHECK:   function_ref @$s4Test24availableInEnabledDomainyyF
-
-  // CHECK: [[FALSE_BB]]:
-  // CHECK:   function_ref @$s4Test26unavailableInEnabledDomainyyF
-  if #available(EnabledDomain) {
-    availableInEnabledDomain()
-  } else {
-    unavailableInEnabledDomain()
-  }
-}
-// CHECK: end sil function '$s4Test28testIfAvailableEnabledDomainyyF'
-
-// CHECK-LABEL: sil{{.*}}$s4Test29testIfAvailableDisabledDomainyyF : $@convention(thin) () -> ()
-public func testIfAvailableDisabledDomain() {
-  // CHECK: bb0:
-  // CHECK:   [[PRED:%.*]] = integer_literal $Builtin.Int1, 0
-  // CHECK:   cond_br [[PRED]], [[TRUE_BB:bb[0-9]+]], [[FALSE_BB:bb[0-9]+]]
-
-  // CHECK: [[TRUE_BB]]:
-  // CHECK:   function_ref @$s4Test25availableInDisabledDomainyyF
-
-  // CHECK: [[FALSE_BB]]:
-  // CHECK:   function_ref @$s4Test27unavailableInDisabledDomainyyF
-  if #available(DisabledDomain) {
-    availableInDisabledDomain()
-  } else {
-    unavailableInDisabledDomain()
-  }
-}
-// CHECK: end sil function '$s4Test29testIfAvailableDisabledDomainyyF'
+// CHECK-NOOPT: s4Test49availableInEnabledDomainAndUnavailableUniversallyyyF
+// CHECK-OPT-NOT: s4Test49availableInEnabledDomainAndUnavailableUniversallyyyF
+@available(*, unavailable)
+@available(EnabledDomain)
+public func availableInEnabledDomainAndUnavailableUniversally() { }
+
+// CHECK-NOT: s4Test40unavailableInEnabledDomainAndUniversallyyyF
+@available(*, unavailable)
+@available(EnabledDomain, unavailable)
+public func unavailableInEnabledDomainAndUniversally() { }
 
+// CHECK-NOT: s4Test50availableInDisabledDomainAndUnavailableUniversallyyyF
+@available(*, unavailable)
+@available(DisabledDomain)
+public func availableInDisabledDomainAndUnavailableUniversally() { }
+
+// CHECK-NOOPT: s4Test41unavailableInDisabledDomainAndUniversallyyyF
+// CHECK-OPT-NOT: s4Test41unavailableInDisabledDomainAndUniversallyyyF
+@available(*, unavailable)
+@available(DisabledDomain, unavailable)
+public func unavailableInDisabledDomainAndUniversally() { }
diff --git a/test/SILGen/unavailable_decl_optimization_stub.swift b/test/SILGen/unavailable_decl_optimization_stub.swift
index e0467bb57864d..ee5f53f9dfb28 100644
--- a/test/SILGen/unavailable_decl_optimization_stub.swift
+++ b/test/SILGen/unavailable_decl_optimization_stub.swift
@@ -12,6 +12,14 @@ public func unavailableFunc() -> S {
   return S()
 }
 
+// CHECK-LABEL: sil{{.*}}@$s4Test33unavailableFuncIntroducedInSwift5yyF
+// CHECK:         [[FNREF:%.*]] = function_ref @$[[DIAGNOSEFN:(ss31_diagnoseUnavailableCodeReacheds5NeverOyF|ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb)]] : $@convention(thin) () -> Never
+// CHECK-NEXT:    [[APPLY:%.*]] = apply [[FNREF]]()
+// CHECK:       } // end sil function '$s4Test33unavailableFuncIntroducedInSwift5yyF'
+@available(*, unavailable)
+@available(swift 5)
+public func unavailableFuncIntroducedInSwift5() { }
+
 // CHECK-LABEL: sil{{.*}}@$s4Test025unavailableFuncWithNestedC0yyF
 // CHECK:         [[FNREF:%.*]] = function_ref @$[[DIAGNOSEFN:(ss31_diagnoseUnavailableCodeReacheds5NeverOyF|ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb)]] : $@convention(thin) () -> Never
 // CHECK-NEXT:    [[APPLY:%.*]] = apply [[FNREF]]()
diff --git a/test/SILGen/unavailable_decl_optimization_stub_macos.swift b/test/SILGen/unavailable_decl_optimization_stub_macos.swift
index 2ce1bc611bce7..8ca4c1241f6d6 100644
--- a/test/SILGen/unavailable_decl_optimization_stub_macos.swift
+++ b/test/SILGen/unavailable_decl_optimization_stub_macos.swift
@@ -24,6 +24,14 @@ public func unavailableFunc() {}
 @available(macOS, unavailable)
 public func unavailableOnMacOSFunc() {}
 
+// CHECK-LABEL:     sil{{.*}}@$s4Test36unavailableFuncWithMacOSIntroductionyyF
+// CHECK:             [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb : $@convention(thin) () -> Never
+// CHECK-NEXT:        [[APPLY:%.*]] = apply [[FNREF]]()
+// CHECK:           } // end sil function '$s4Test36unavailableFuncWithMacOSIntroductionyyF'
+@available(*, unavailable)
+@available(macOS 12.0, *)
+public func unavailableFuncWithMacOSIntroduction() {}
+
 // CHECK-LABEL:     sil{{.*}}@$s4Test31unavailableOnMacOSExtensionFuncyyF
 // CHECK-NOT:         _diagnoseUnavailableCodeReached
 // CHECK:           } // end sil function '$s4Test31unavailableOnMacOSExtensionFuncyyF'
diff --git a/test/SILGen/unowned-class-bound-generic-parameter.swift b/test/SILGen/unowned-class-bound-generic-parameter.swift
index 64f3f76303961..f2755390982a4 100644
--- a/test/SILGen/unowned-class-bound-generic-parameter.swift
+++ b/test/SILGen/unowned-class-bound-generic-parameter.swift
@@ -34,4 +34,4 @@ func f1<T: AnyObject>(t: T) {
 
 func f2<T: AnyObject, U: AnyObject>(u: U, tt: Array<Wrapper<T>>) {
   _ = tt.map { _ in Wrapper(t: u) }
-}
\ No newline at end of file
+}
diff --git a/test/SILGen/variadic-generic-tuples.swift b/test/SILGen/variadic-generic-tuples.swift
index 6c63a4881101a..007253c2be790 100644
--- a/test/SILGen/variadic-generic-tuples.swift
+++ b/test/SILGen/variadic-generic-tuples.swift
@@ -102,7 +102,7 @@ public struct Container<each T> {
 //   Finally, the actual assignment.
 // CHECK-NEXT:    [[ACCESS:%.*]] = begin_access [modify] [unknown] %1 :
 // CHECK-NEXT:    [[FIELD:%.*]] = struct_element_addr [[ACCESS]] : $*Container<repeat each T>, #Container.storage
-// CHECK-NEXT:    copy_addr [take] [[COPY2]] to [[FIELD]] : $*(repeat Stored<each T>)
+// CHECK-NEXT:    copy_addr [[COPY2]] to [[FIELD]] : $*(repeat Stored<each T>)
 // CHECK-NEXT:    end_access [[ACCESS]]
 //   Clean up.
 // CHECK-NEXT:    dealloc_stack [[COPY2]]
diff --git a/test/SILGen/variadic.swift b/test/SILGen/variadic.swift
new file mode 100644
index 0000000000000..7769110734cfc
--- /dev/null
+++ b/test/SILGen/variadic.swift
@@ -0,0 +1,20 @@
+// RUN: %swift_frontend_plain -emit-silgen %s -I %S/Inputs -o - -parse-as-library -verify -enable-experimental-feature ImportMacroAliases | %FileCheck %s
+
+// REQUIRES: swift_feature_ImportMacroAliases
+
+import Variadic
+
+public func f() {
+  withVaList([0.0]) {
+    u_vformatMessage(0, $0)
+  }
+}
+
+            // closure #1 in f()
+// CHECK: bb0(%0 : $*(), %1 : $CVaListPointer):
+            // function_ref u_vformatMessage.getter
+// CHECK: [[PROJECTION:%.*]] = function_ref @$sSC16u_vformatMessageyys5Int32V_s14CVaListPointerVSgtcvg : $@convention(thin) () -> @owned @callee_guaranteed (Int32, Optional<CVaListPointer>) -> ()
+// CHECK: [[FUNCTION:%.*]] = apply [[PROJECTION]]() : $@convention(thin) () -> @owned @callee_guaranteed (Int32, Optional<CVaListPointer>) -> ()
+// CHECK: [[VALIST:%.*]] = enum $Optional<CVaListPointer>, #Optional.some!enumelt, %1
+// CHECK: [[BORROW:%.*]] = begin_borrow [[FUNCTION]]
+// CHECK: {{.*}} = apply [[BORROW]]({{.*}}, [[VALIST]]) : $@callee_guaranteed (Int32, Optional<CVaListPointer>) -> ()
diff --git a/test/SILGen/weak.swift b/test/SILGen/weak.swift
index 73a443d8f740a..0e3a6f5f9276a 100644
--- a/test/SILGen/weak.swift
+++ b/test/SILGen/weak.swift
@@ -1,4 +1,3 @@
-
 // RUN: %target-swift-emit-silgen -Xllvm -sil-print-types -module-name weak -Xllvm -sil-full-demangle %s | %FileCheck %s
 
 class C {
@@ -67,6 +66,16 @@ func testClosureOverWeak() {
   takeClosure { bC!.f() }
 }
 
+func testClosureOverWeakLet() {
+  weak let bC = C()
+  takeClosure { bC!.f() }
+}
+
+func testClosureOverWeakCapture() {
+  let bC = C()
+  takeClosure { [weak bC] in bC!.f() }
+}
+
 class CC {
   weak var x: CC?
 
diff --git a/test/SILGen/witness_same_type.swift b/test/SILGen/witness_same_type.swift
index dc7152246e60b..676558400c310 100644
--- a/test/SILGen/witness_same_type.swift
+++ b/test/SILGen/witness_same_type.swift
@@ -33,3 +33,58 @@ public struct LazySequenceOf<SS : Sequence, A> : Sequence where SS.Iterator.Elem
     } 
   }
 }
+
+// rdar://problem/155465011
+
+// Due to a series of unfortunate coincidences, we would assign the same mangling
+// to the witness thunks for P1.f() in the S1: P1 and S2: P1 conformance.
+
+public protocol P1 {
+  func f<T: P2>(_: T) where T.A == Self
+}
+
+public protocol P2 {
+  associatedtype A: P1
+}
+
+struct N1: P2 {
+  typealias A = S1
+}
+
+struct N2: P2 {
+  typealias A = S2
+}
+
+struct S1: P1 {
+  func f<T: P2>(_: T) where T.A == Self {
+    print("Hello from S1")
+  }
+}
+
+struct S2: P1 {
+  func f<T: P2>(_: T) where T.A == Self {
+    print("Hello from S2")
+  }
+}
+
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s17witness_same_type2S1VAA2P1A2aDP1fyyqd__1AQyd__RszAA2P2Rd__lFTW : $@convention(witness_method: P1) <τ_0_0 where τ_0_0 : P2, τ_0_0.A == S1> (@in_guaranteed τ_0_0, @in_guaranteed S1) -> () {
+
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s17witness_same_type2S2VAA2P1A2aDP1fyyqd__1AQyd__RszAA2P2Rd__lFTW : $@convention(witness_method: P1) <τ_0_0 where τ_0_0 : P2, τ_0_0.A == S2> (@in_guaranteed τ_0_0, @in_guaranteed S2) -> () {
+
+// CHECK-LABEL: sil_witness_table hidden N1: P2 module witness_same_type {
+// CHECK-NEXT:    associated_conformance (A: P1): S1: P1 module witness_same_type
+// CHECK-NEXT:    associated_type A: S1
+// CHECK-NEXT:  }
+
+// CHECK-LABEL: sil_witness_table hidden N2: P2 module witness_same_type {
+// CHECK-NEXT:    associated_conformance (A: P1): S2: P1 module witness_same_type
+// CHECK-NEXT:    associated_type A: S2
+// CHECK-NEXT:  }
+
+// CHECK-LABEL: sil_witness_table hidden S1: P1 module witness_same_type {
+// CHECK-NEXT:    method #P1.f: <Self><T where Self == T.A, T : P2> (Self) -> (T) -> () : @$s17witness_same_type2S1VAA2P1A2aDP1fyyqd__1AQyd__RszAA2P2Rd__lFTW
+// CHECK-NEXT:  }
+
+// CHECK-LABEL: sil_witness_table hidden S2: P1 module witness_same_type {
+// CHECK-NEXT:    method #P1.f: <Self><T where Self == T.A, T : P2> (Self) -> (T) -> () : @$s17witness_same_type2S2VAA2P1A2aDP1fyyqd__1AQyd__RszAA2P2Rd__lFTW
+// CHECK-NEXT:  }
diff --git a/test/SILOptimizer/Inputs/SpanExtras.swift b/test/SILOptimizer/Inputs/SpanExtras.swift
index 5775ccce3417d..c591c4dc337f5 100644
--- a/test/SILOptimizer/Inputs/SpanExtras.swift
+++ b/test/SILOptimizer/Inputs/SpanExtras.swift
@@ -1,56 +1,5 @@
 import Builtin
 
-/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
-/// a value identical to `dependent` with a lifetime dependency on the caller's
-/// borrow scope of the `source` argument.
-@unsafe
-@_unsafeNonescapableResult
-@_alwaysEmitIntoClient
-@_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, borrowing source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
-
-/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
-/// a value identical to `dependent` that inherits all lifetime dependencies from
-/// the `source` argument.
-@unsafe
-@_unsafeNonescapableResult
-@_alwaysEmitIntoClient
-@_transparent
-@lifetime(copy source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, copying source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
-
-@unsafe
-@_unsafeNonescapableResult
-@_alwaysEmitIntoClient
-@_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, mutating source: inout U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
-
 // A MutableSpan<Element> represents a span of memory which
 // contains initialized `Element` instances.
 @frozen
@@ -66,7 +15,7 @@ public struct MutableSpan<Element: ~Copyable>: ~Copyable & ~Escapable {
   }
 
   @usableFromInline @inline(__always)
-  @lifetime(borrow start)
+  @_lifetime(borrow start)
   init(
     _unchecked start: UnsafeMutableRawPointer?,
     count: Int
@@ -84,7 +33,7 @@ extension MutableSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
   @usableFromInline @inline(__always)
-  @lifetime(borrow elements)
+  @_lifetime(borrow elements)
   internal init(
     _unchecked elements: UnsafeMutableBufferPointer<Element>
   ) {
@@ -93,7 +42,7 @@ extension MutableSpan where Element: ~Copyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(borrow buffer)
+  @_lifetime(borrow buffer)
   public init(
     _unsafeElements buffer: UnsafeMutableBufferPointer<Element>
   ) {
@@ -107,7 +56,7 @@ extension MutableSpan where Element: ~Copyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(borrow start)
+  @_lifetime(borrow start)
   public init(
     _unsafeStart start: UnsafeMutablePointer<Element>,
     count: Int
@@ -123,7 +72,7 @@ extension MutableSpan where Element: ~Copyable {
 extension MutableSpan {
 
   @_alwaysEmitIntoClient
-  @lifetime(borrow elements)
+  @_lifetime(borrow elements)
   public init(
     _unsafeElements elements: borrowing Slice<UnsafeMutableBufferPointer<Element>>
   ) {
@@ -137,7 +86,7 @@ extension MutableSpan {
 extension MutableSpan where Element: BitwiseCopyable {
 
   @_alwaysEmitIntoClient
-  @lifetime(borrow buffer)
+  @_lifetime(borrow buffer)
   public init(
     _unsafeBytes buffer: UnsafeMutableRawBufferPointer
   ) {
@@ -158,7 +107,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(borrow pointer)
+  @_lifetime(borrow pointer)
   public init(
     _unsafeStart pointer: UnsafeMutableRawPointer,
     byteCount: Int
@@ -170,7 +119,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(borrow buffer)
+  @_lifetime(borrow buffer)
   public init(
     _unsafeBytes buffer: borrowing Slice<UnsafeMutableRawBufferPointer>
   ) {
@@ -184,7 +133,7 @@ extension MutableSpan where Element: BitwiseCopyable {
 extension Span where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
-  @lifetime(borrow mutableSpan)
+  @_lifetime(borrow mutableSpan)
   public init(_unsafeMutableSpan mutableSpan: borrowing MutableSpan<Element>) {
     let pointer = mutableSpan._pointer?.assumingMemoryBound(to: Element.self)
     let buffer = UnsafeBufferPointer(start: pointer, count: mutableSpan.count)
@@ -198,7 +147,7 @@ extension MutableSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
   public var storage: Span<Element> {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     borrowing get {
       Span(_unsafeMutableSpan: self)
     }
@@ -216,7 +165,7 @@ extension MutableSpan where Element: ~Copyable {
 extension RawSpan {
 
   @_alwaysEmitIntoClient
-  @lifetime(borrow mutableSpan)
+  @_lifetime(borrow mutableSpan)
   public init<Element: BitwiseCopyable>(
     _unsafeMutableSpan mutableSpan: borrowing MutableSpan<Element>
   ) {
@@ -280,20 +229,6 @@ extension MutableSpan where Element: ~Copyable {
   }
 }
 
-@available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
-extension MutableSpan where Element: BitwiseCopyable {
-
-  /// Construct a RawSpan over the memory represented by this span
-  ///
-  /// - Returns: a RawSpan over the memory represented by this span
-  @unsafe //FIXME: remove when the lifetime inference is fixed
-  @_alwaysEmitIntoClient
-  public var _unsafeRawSpan: RawSpan {
-    @lifetime(borrow self)
-    get { RawSpan(_unsafeMutableSpan: self) }
-  }
-}
-
 @available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
 extension MutableSpan where Element: ~Copyable {
 
@@ -305,12 +240,11 @@ extension MutableSpan where Element: ~Copyable {
   /// - Complexity: O(1)
   @_alwaysEmitIntoClient
   public subscript(_ position: Index) -> Element {
-    @lifetime(borrow self)
     _read {
       precondition(indices.contains(position), "index out of bounds")
       yield self[unchecked: position]
     }
-    @lifetime(borrow self)
+    @_lifetime(self: copy self)
     _modify {
       precondition(indices.contains(position), "index out of bounds")
       yield &self[unchecked: position]
@@ -330,7 +264,7 @@ extension MutableSpan where Element: ~Copyable {
     unsafeAddress {
       UnsafePointer(_unsafeAddressOfElement(unchecked: position))
     }
-    @lifetime(self: copy self)
+    @_lifetime(self: copy self)
     unsafeMutableAddress {
       _unsafeAddressOfElement(unchecked: position)
     }
@@ -350,14 +284,14 @@ extension MutableSpan where Element: ~Copyable {
 @available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
 extension MutableSpan where Element: ~Copyable {
 
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func swapAt(_ i: Index, _ j: Index) {
     precondition(indices.contains(Index(i)))
     precondition(indices.contains(Index(j)))
     swapAt(unchecked: i, unchecked: j)
   }
 
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func swapAt(unchecked i: Index, unchecked j: Index) {
     let pi = _unsafeAddressOfElement(unchecked: i)
     let pj = _unsafeAddressOfElement(unchecked: j)
@@ -382,7 +316,7 @@ extension MutableSpan where Element: BitwiseCopyable {
       precondition(indices.contains(position))
       return self[unchecked: position]
     }
-    @lifetime(self: copy self)
+    @_lifetime(self: copy self)
     set {
       precondition(indices.contains(position))
       self[unchecked: position] = newValue
@@ -403,7 +337,7 @@ extension MutableSpan where Element: BitwiseCopyable {
       let offset = position&*MemoryLayout<Element>.stride
       return _start().loadUnaligned(fromByteOffset: offset, as: Element.self)
     }
-    @lifetime(self: copy self)
+    @_lifetime(self: copy self)
     set {
       let offset = position&*MemoryLayout<Element>.stride
       _start().storeBytes(of: newValue, toByteOffset: offset, as: Element.self)
@@ -424,7 +358,7 @@ extension MutableSpan where Element: ~Copyable {
 
   //FIXME: mark closure parameter as non-escaping
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func withUnsafeMutableBufferPointer<E: Error, Result: ~Copyable>(
     _ body: (UnsafeMutableBufferPointer<Element>) throws(E) -> Result
   ) throws(E) -> Result {
@@ -453,7 +387,7 @@ extension MutableSpan where Element: BitwiseCopyable {
 
   //FIXME: mark closure parameter as non-escaping
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func withUnsafeMutableBytes<E: Error, Result: ~Copyable>(
     _ body: (_ buffer: UnsafeMutableRawBufferPointer) throws(E) -> Result
   ) throws(E) -> Result {
@@ -470,7 +404,7 @@ extension MutableSpan where Element: BitwiseCopyable {
 extension MutableSpan {
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(repeating repeatedValue: Element) {
     _start().withMemoryRebound(to: Element.self, capacity: count) {
       $0.update(repeating: repeatedValue, count: count)
@@ -478,7 +412,7 @@ extension MutableSpan {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update<S: Sequence>(
     from source: S
   ) -> (unwritten: S.Iterator, index: Index) where S.Element == Element {
@@ -488,7 +422,7 @@ extension MutableSpan {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(
     from elements: inout some IteratorProtocol<Element>
   ) -> Index {
@@ -502,7 +436,7 @@ extension MutableSpan {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: some Collection<Element>
   ) -> Index {
@@ -523,7 +457,7 @@ extension MutableSpan {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(fromContentsOf source: Span<Element>) -> Index {
     guard !source.isEmpty else { return 0 }
     precondition(
@@ -539,7 +473,7 @@ extension MutableSpan {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: borrowing MutableSpan<Element>
   ) -> Index {
@@ -552,7 +486,7 @@ extension MutableSpan {
 extension MutableSpan where Element: BitwiseCopyable {
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(
     repeating repeatedValue: Element
   ) where Element: BitwiseCopyable {
@@ -565,7 +499,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update<S: Sequence>(
     from source: S
   ) -> (unwritten: S.Iterator, index: Index)
@@ -576,7 +510,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(
     from elements: inout some IteratorProtocol<Element>
   ) -> Index {
@@ -590,7 +524,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: some Collection<Element>
   ) -> Index where Element: BitwiseCopyable {
@@ -611,7 +545,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: Span<Element>
   ) -> Index where Element: BitwiseCopyable {
@@ -629,7 +563,7 @@ extension MutableSpan where Element: BitwiseCopyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func update(
     fromContentsOf source: borrowing MutableSpan<Element>
   ) -> Index where Element: BitwiseCopyable {
@@ -670,7 +604,7 @@ public struct OutputSpan<Element: ~Copyable>: ~Copyable, ~Escapable {
   }
 
   @usableFromInline @inline(__always)
-  @lifetime(borrow start)
+  @_lifetime(borrow start)
   init(
     _unchecked start: UnsafeMutableRawPointer?,
     capacity: Int,
@@ -687,13 +621,93 @@ public struct OutputSpan<Element: ~Copyable>: ~Copyable, ~Escapable {
 extension OutputSpan: Sendable {}
 
 @available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
-extension OutputSpan where Element: ~Copyable {
+extension OutputSpan where Element: ~Copyable  {
+  @unsafe
+  @_alwaysEmitIntoClient
+  @_lifetime(borrow buffer)
+  public init(
+    _uncheckedBuffer buffer: UnsafeMutableBufferPointer<Element>,
+    initializedCount: Int
+  ) {
+    unsafe _pointer = .init(buffer.baseAddress)
+    capacity = buffer.count
+    _initialized = initializedCount
+  }
+
+  /// Unsafely create an OutputSpan over partly-initialized memory.
+  ///
+  /// The memory in `buffer` must remain valid throughout the lifetime
+  /// of the newly-created `OutputSpan`. Its prefix must contain
+  /// `initializedCount` initialized instances, followed by uninitialized
+  /// memory. The default value of `initializedCount` is 0, representing
+  /// the common case of a completely uninitialized `buffer`.
+  ///
+  /// - Parameters:
+  ///   - buffer: an `UnsafeMutableBufferPointer` to be initialized
+  ///   - initializedCount: the number of initialized elements
+  ///                       at the beginning of `buffer`.
+  @unsafe
+  @_alwaysEmitIntoClient
+  @_lifetime(borrow buffer)
+  public init(
+    buffer: UnsafeMutableBufferPointer<Element>,
+    initializedCount: Int
+  ) {
+    precondition(buffer._isWellAligned(), "Misaligned OutputSpan")
+    if let baseAddress = buffer.baseAddress {
+      precondition(
+        unsafe baseAddress.advanced(by: buffer.count) >= baseAddress,
+        "Buffer must not wrap around the address space"
+      )
+    }
+    precondition(
+      0 <= initializedCount && initializedCount <= buffer.count,
+      "OutputSpan count is not within capacity"
+    )
+    unsafe self.init(
+      _uncheckedBuffer: buffer, initializedCount: initializedCount
+    )
+  }
+}
+
+extension UnsafePointer where Pointee: ~Copyable {
+  @safe
+  @_alwaysEmitIntoClient
+  public func _isWellAligned() -> Bool {
+    (Int(bitPattern: self) & (MemoryLayout<Pointee>.alignment &- 1)) == 0
+  }
+}
+
+extension UnsafeMutablePointer where Pointee: ~Copyable {
+  @safe
+  @_alwaysEmitIntoClient
+  public func _isWellAligned() -> Bool {
+    (Int(bitPattern: self) & (MemoryLayout<Pointee>.alignment &- 1)) == 0
+  }
+}
+
+extension UnsafeBufferPointer where Element: ~Copyable {
+  @safe
+  @_alwaysEmitIntoClient
+  public func _isWellAligned() -> Bool {
+    guard let p = baseAddress else { return true }
+    return p._isWellAligned()
+  }
+}
+
+extension UnsafeMutableBufferPointer  where Element: ~Copyable {
+  @inlinable
+  public func _isWellAligned() -> Bool {
+    guard let p = baseAddress else { return true }
+    return p._isWellAligned()
+  }
+}
+
+@available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
+extension OutputSpan where Element: ~Copyable  {
 
-@available(macOS 9999, *)
-@available(macOS 9999, *)
-@available(macOS 9999, *)
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func append(_ value: consuming Element) {
     precondition(_initialized < capacity, "Output buffer overflow")
     let p = _start.advanced(by: _initialized&*MemoryLayout<Element>.stride)
@@ -723,7 +737,7 @@ extension OutputSpan where Element: ~Copyable {
 extension OutputSpan {
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func append(repeating repeatedValue: Element, count: Int) {
     let available = capacity &- _initialized
     precondition(
@@ -739,7 +753,7 @@ extension OutputSpan {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func append<S>(
     from elements: S
   ) -> S.Iterator where S: Sequence, S.Element == Element {
@@ -749,7 +763,7 @@ extension OutputSpan {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func append(
     from elements: inout some IteratorProtocol<Element>
   ) {
@@ -762,16 +776,12 @@ extension OutputSpan {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func append(
     fromContentsOf source: some Collection<Element>
   ) {
     let void: Void? = source.withContiguousStorageIfAvailable {
-#if false
       append(fromContentsOf: Span(_unsafeElements: $0))
-#else //FIXME: remove once rdar://136838539 & rdar://136849171 are fixed
-      append(fromContentsOf: $0)
-#endif
     }
     if void != nil {
       return
@@ -792,26 +802,8 @@ extension OutputSpan {
     _initialized &+= copied
   }
 
-  //FIXME: remove once rdar://136838539 & rdar://136849171 are fixed
-  @lifetime(self: copy self)
-  public mutating func append(
-    fromContentsOf source: UnsafeBufferPointer<Element>
-  ) {
-    guard !source.isEmpty else { return }
-    precondition(
-      source.count <= available,
-      "destination span cannot contain every element from source."
-    )
-    let tail = _start.advanced(by: _initialized&*MemoryLayout<Element>.stride)
-    source.baseAddress!.withMemoryRebound(to: Element.self, capacity: source.count) {
-      _ = tail.initializeMemory(as: Element.self, from: $0, count: source.count)
-    }
-    _initialized += source.count
-  }
-
-  //FIXME: rdar://136838539 & rdar://136849171
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func append(
     fromContentsOf source: Span<Element>
   ) {
@@ -830,7 +822,7 @@ extension OutputSpan {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func append(fromContentsOf source: borrowing MutableSpan<Element>) {
     source.withUnsafeBufferPointer { append(fromContentsOf: $0) }
   }
@@ -840,7 +832,7 @@ extension OutputSpan {
 extension OutputSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func moveAppend(
     fromContentsOf source: consuming Self
   ) {
@@ -859,25 +851,12 @@ extension OutputSpan where Element: ~Copyable {
   }
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func moveAppend(
     fromContentsOf source: UnsafeMutableBufferPointer<Element>
   ) {
-#if false //FIXME: rdar://136838539 & rdar://136849171
-    let source = OutputSpan(_initializing: source, initialized: source.count)
+    let source = OutputSpan(buffer: source, initializedCount: source.count)
     moveAppend(fromContentsOf: source)
-#else
-    guard !source.isEmpty else { return }
-    precondition(
-      source.count <= available,
-      "buffer cannot contain every element from source."
-    )
-    let tail = _start.advanced(by: _initialized&*MemoryLayout<Element>.stride)
-    tail.moveInitializeMemory(
-      as: Element.self, from: source.baseAddress!, count: source.count
-    )
-    _initialized &+= source.count
-#endif
   }
 }
 
@@ -885,7 +864,7 @@ extension OutputSpan where Element: ~Copyable {
 extension OutputSpan {
 
   @_alwaysEmitIntoClient
-  @lifetime(self: copy self)
+  @_lifetime(self: copy self)
   public mutating func moveAppend(
     fromContentsOf source: Slice<UnsafeMutableBufferPointer<Element>>
   ) {
@@ -903,7 +882,7 @@ extension OutputSpan where Element: ~Copyable {
 
   @_alwaysEmitIntoClient
   public var span: Span<Element> {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     borrowing get {
       let pointer = _pointer?.assumingMemoryBound(to: Element.self)
       let buffer = UnsafeBufferPointer(start: pointer, count: _initialized)
@@ -912,11 +891,9 @@ extension OutputSpan where Element: ~Copyable {
     }
   }
 
-  /* FIXME: rdar://147194789 ([nonescapable] 'mutating get' causes a
-     type checking error for non-existent _read accessor)
   @_alwaysEmitIntoClient
   public var mutableSpan: MutableSpan<Element> {
-    @lifetime(borrow self)
+    @_lifetime(&self)
     mutating get { // the accessor must provide a mutable projection
       let pointer = _pointer?.assumingMemoryBound(to: Element.self)
       let buffer = UnsafeMutableBufferPointer(start: pointer, count: _initialized)
@@ -924,7 +901,6 @@ extension OutputSpan where Element: ~Copyable {
       return _overrideLifetime(span, mutating: &self)
     }
   }
-   */
 }
 
 @available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
@@ -957,7 +933,7 @@ extension Span {
 
 //  @available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
 //  public static var empty: Span {
-//    @lifetime(immortal)
+//    @_lifetime(immortal)
 //    get {
 //      let nilBasedBuffer = UnsafeBufferPointer<Element>(start: nil, count: 0)
 //      let span = Span(_unsafeElements: nilBasedBuffer)
@@ -966,7 +942,7 @@ extension Span {
 //  }
 //
 //  @available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, visionOS 9999, *)
-//  @lifetime(immortal)
+//  @_lifetime(immortal)
 //  public init() {
 //    let nilBasedBuffer = UnsafeBufferPointer<Element>(start: nil, count: 0)
 //    let span = Span(_unsafeElements: nilBasedBuffer)
diff --git a/test/SILOptimizer/Inputs/bitfield.h b/test/SILOptimizer/Inputs/bitfield.h
index 920725a99de55..3068bdee0fb08 100644
--- a/test/SILOptimizer/Inputs/bitfield.h
+++ b/test/SILOptimizer/Inputs/bitfield.h
@@ -3,3 +3,10 @@ struct S {
     int a;
     int b : 8;
 };
+
+struct S2 {
+  int a;
+  int :4;
+  int b;
+};
+
diff --git a/test/SILOptimizer/OSLogMandatoryOptTest.sil b/test/SILOptimizer/OSLogMandatoryOptTest.sil
index 591098ebc0a1c..1d9251240f047 100644
--- a/test/SILOptimizer/OSLogMandatoryOptTest.sil
+++ b/test/SILOptimizer/OSLogMandatoryOptTest.sil
@@ -27,7 +27,7 @@ bb0(%0 : @owned $String):
 }
 
 // String.init(_builtinStringLiteral:utf8CodeUnitCount:isASCII:)
-sil [serialized] [always_inline] [readonly] [_semantics "string.makeUTF8"] @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
+sil [serialized] [heuristic_always_inline] [readonly] [_semantics "string.makeUTF8"] @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
 
 /// A function that models the use of a string in some arbitrary way.
 sil @useFormatString: $@convention(thin) (@guaranteed String) -> ()
@@ -66,6 +66,34 @@ bb0:
   return %13 : $()
 }
 
+// CHECK-LABEL: @testConstantFoldingOfStructExtractMetatypeArg :
+// CHECK-DAG: [[STRINGUSE:%[0-9]+]] = function_ref @useFormatString
+// CHECK-DAG: {{%.*}} = apply [[STRINGUSE]]([[BORROW:%[0-9]+]])
+// CHECK-DAG: [[BORROW]] = begin_borrow [[STRINGCONST:%[0-9]+]]
+// CHECK-DAG: [[STRINGCONST]] = apply [[STRINGINIT:%[0-9]+]]([[LIT:%[0-9]+]], {{%.*}}, {{%.*}}, {{%.*}})
+// CHECK-DAG: [[STRINGINIT]] = function_ref @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC
+// CHECK-DAG: [[LIT]] = string_literal oslog "test message: %lld"
+// CHECK-DAG: destroy_value [[STRINGCONST]] : $String
+sil [ossa] @testConstantFoldingOfStructExtractMetatypeArg : $@convention(thin) (@thin String.Type) -> () {
+bb0(%0 : $@thin String.Type):
+  %1 = string_literal utf8 "test message: %lld"
+  %2 = integer_literal $Builtin.Word, 18
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = function_ref @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
+  %5 = apply %4(%1, %2, %3, %0) : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
+  %6 = function_ref @oslogMessageInit : $@convention(thin) (@owned String) -> @owned OSLogMessageStub
+  %7 = apply %6(%5) : $@convention(thin) (@owned String) -> @owned OSLogMessageStub
+  %8 = begin_borrow %7
+  %9 = struct_extract %8, #OSLogMessageStub.interpolation
+  %10 = struct_extract %9, #OSLogInterpolationStub.formatString
+  %11 = function_ref @useFormatString : $@convention(thin) (@guaranteed String) -> ()
+  %12 = apply %11(%10) : $@convention(thin) (@guaranteed String) -> ()
+  end_borrow %8
+  destroy_value %7
+  %15 = tuple ()
+  return %15
+}
+
 /// A function that models the use of a string in some arbitrary way.
 sil @useFormatStringIndirect: $@convention(thin) (@in_guaranteed String) -> ()
 
@@ -373,7 +401,7 @@ bb0(%0 : $Builtin.Int1):
 }
 
 // _allocateUninitializedArray<A>(_:)
-sil [serialized] [always_inline] [_semantics "array.uninitialized_intrinsic"] @$ss27_allocateUninitializedArrayySayxG_BptBwlF : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
+sil [serialized] [heuristic_always_inline] [_semantics "array.uninitialized_intrinsic"] @$ss27_allocateUninitializedArrayySayxG_BptBwlF : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
 
 /// A function that models the use of an array.
 sil @useArray: $@convention(thin) (@guaranteed Array<Int64>) -> ()
diff --git a/test/SILOptimizer/abcopts.sil b/test/SILOptimizer/abcopts.sil
index 86649b2cae07b..e844c1d2202ad 100644
--- a/test/SILOptimizer/abcopts.sil
+++ b/test/SILOptimizer/abcopts.sil
@@ -607,7 +607,7 @@ bb2:
   return %23 : $Int32
 }
 
-// HOIST-LABEL: sil @hoist_rangechecked
+// HOIST-LABEL: sil @hoist_rangechecked :
 // HOIST: bb0
 // HOIST:  cond_br {{.*}}, bb2, bb1
 // HOIST: bb1:
@@ -667,6 +667,64 @@ bb3:
   return %23 : $Int32
 }
 
+// HOIST-LABEL: sil @hoist_rangechecked_sgt :
+// HOIST:       bb0
+// HOIST:        cond_br {{.*}}, bb2, bb1
+// HOIST:       bb1:
+// HOIST:         [[CB:%[0-9]+]] = function_ref @checkbounds
+// HOIST:          apply [[CB]]
+// HOIST:         br bb3{{.*}}
+// HOIST:       bb3{{.*}}:
+// HOIST-NOT:     function_ref @checkbounds
+// HOIST-NOT:     apply [[CB]]
+// HOIST:         cond_br {{.*}}, bb5, bb4
+// HOIST:       bb4
+// HOIST:         br bb3
+// HOIST:       bb5
+// HOIST:         br bb6
+// HOIST:       bb6{{.*}}:
+// HOIST:       } // end sil function 'hoist_rangechecked_sgt'
+
+sil @hoist_rangechecked_sgt : $@convention(thin) (Int32, @inout ArrayInt) -> Int32 {
+bb0(%0 : $Int32, %24 : $*ArrayInt):
+  %100 = integer_literal $Builtin.Int1, -1
+  %101 = struct $Bool(%100 : $Builtin.Int1)
+  %1 = struct_extract %0 : $Int32, #Int32._value
+  %2 = integer_literal $Builtin.Int32, 0
+  %14 = builtin "cmp_sgt_Int32"(%2 : $Builtin.Int32, %1 : $Builtin.Int32) : $Builtin.Int1
+  cond_fail %14 : $Builtin.Int1
+  br bb1(%2 : $Builtin.Int32)
+
+bb1(%4 : $Builtin.Int32):
+  %8 = builtin "cmp_eq_Int32"(%4 : $Builtin.Int32, %1 : $Builtin.Int32) : $Builtin.Int1
+  cond_br %8, bb3, bb4
+
+bb4:
+  %37 = struct $Int32(%4 : $Builtin.Int32)
+  %52 = function_ref @checkbounds : $@convention(method) (Int32, Bool, @owned ArrayInt) -> _DependenceToken
+  %53 = load %24 : $*ArrayInt
+  %54 = struct_extract %53 : $ArrayInt, #ArrayInt.buffer
+  %55 = struct_extract %54 : $ArrayIntBuffer, #ArrayIntBuffer.storage
+  retain_value %55 : $Builtin.NativeObject
+  %58 = apply %52(%37, %101, %53) : $@convention(method) (Int32, Bool, @owned ArrayInt) -> _DependenceToken
+  %10 = integer_literal $Builtin.Int32, 1
+  %19 = integer_literal $Builtin.Int1, -1
+  %20 = builtin "sadd_with_overflow_Int32"(%4 : $Builtin.Int32, %10 : $Builtin.Int32, %19 : $Builtin.Int1) : $(Builtin.Int32, Builtin.Int1)
+  %21 = tuple_extract %20 : $(Builtin.Int32, Builtin.Int1), 0
+
+  %40 = function_ref @getElementAddr : $@convention(method) (Int32, @owned ArrayInt) -> UnsafeMutablePointerInt
+  retain_value %55 : $Builtin.NativeObject
+  %42 = apply %40(%37, %53) : $@convention(method) (Int32, @owned ArrayInt) -> UnsafeMutablePointerInt
+  %43 = struct_extract %42 : $UnsafeMutablePointerInt, #UnsafeMutablePointerInt._rawValue
+  %44 = pointer_to_address %43 : $Builtin.RawPointer to [strict] $*Int32
+  store %0 to %44 : $*Int32
+  br bb1(%21 : $Builtin.Int32)
+
+bb3:
+  %23 = struct $Int32 (%4 : $Builtin.Int32)
+  return %23 : $Int32
+}
+
 // HOIST-LABEL: sil @hoist_rangechecked_ref_tail_addr
 // HOIST: bb0
 // HOIST:  cond_br {{.*}}, bb2, bb1
@@ -886,7 +944,7 @@ bb3:
   return %23 : $Int32
 }
 
-// HOIST-LABEL: hoist_inclusive_rangechecked
+// HOIST-LABEL: hoist_inclusive_rangechecked :
 // HOIST: bb0
 // HOIST:  cond_br {{.*}}, bb2, bb1
 // HOIST: bb1:
@@ -945,6 +1003,62 @@ bb3:
   return %23 : $Int32
 }
 
+// HOIST-LABEL: hoist_inclusive_rangechecked_sgt :
+// HOIST:       bb0
+// HOIST:        cond_br {{.*}}, bb2, bb1
+// HOIST:       bb1:
+// HOIST:         [[CB:%[0-9]+]] = function_ref @checkbounds
+// HOIST:          apply [[CB]]
+// HOIST:         br bb3{{.*}}
+// HOIST:       bb3{{.*}}:
+// HOIST-NOT:     function_ref @checkbounds
+// HOIST-NOT:     apply [[CB]]
+// HOIST:         cond_br {{.*}}, bb5, bb4
+// HOIST:       bb4:
+// HOIST:        br bb3
+// HOIST:       bb5:
+// HOIST:        br bb6
+// HOIST:       bb6{{.*}}:
+// HOIST:       } // end sil function 'hoist_inclusive_rangechecked_sgt'
+sil @hoist_inclusive_rangechecked_sgt : $@convention(thin) (Int32, @inout ArrayInt) -> Int32 {
+bb0(%0 : $Int32, %24 : $*ArrayInt):
+  %100 = integer_literal $Builtin.Int1, -1
+  %101 = struct $Bool(%100 : $Builtin.Int1)
+  %1 = struct_extract %0 : $Int32, #Int32._value
+  %2 = integer_literal $Builtin.Int32, 0
+  %14 = builtin "cmp_sgt_Int32"(%2 : $Builtin.Int32, %1 : $Builtin.Int32) : $Builtin.Int1
+  cond_fail %14 : $Builtin.Int1
+  %63 = integer_literal $Builtin.Int32, 1
+  %65 = integer_literal $Builtin.Int1, 0
+  %66 = builtin "sadd_with_overflow_Int32"(%1 : $Builtin.Int32, %63 : $Builtin.Int32, %65 : $Builtin.Int1) : $(Builtin.Int32, Builtin.Int1)
+  %67 = tuple_extract %66 : $(Builtin.Int32, Builtin.Int1), 0
+  %70 = builtin "cmp_sle_Int32"(%67 : $Builtin.Int32, %1 : $Builtin.Int32) : $Builtin.Int1
+  cond_fail %70 : $Builtin.Int1
+  br bb1(%2 : $Builtin.Int32)
+
+bb1(%4 : $Builtin.Int32):
+  %8 = builtin "cmp_eq_Int32"(%4 : $Builtin.Int32, %67 : $Builtin.Int32) : $Builtin.Int1
+  cond_br %8, bb3, bb4
+
+bb4:
+  %37 = struct $Int32(%4 : $Builtin.Int32)
+  %52 = function_ref @checkbounds : $@convention(method) (Int32, Bool, @owned ArrayInt) -> _DependenceToken
+  %53 = load %24 : $*ArrayInt
+  %54 = struct_extract %53 : $ArrayInt, #ArrayInt.buffer
+  %55 = struct_extract %54 : $ArrayIntBuffer, #ArrayIntBuffer.storage
+  retain_value %55 : $Builtin.NativeObject
+  %58 = apply %52(%37, %101, %53) : $@convention(method) (Int32, Bool, @owned ArrayInt) -> _DependenceToken
+  %10 = integer_literal $Builtin.Int32, 1
+  %19 = integer_literal $Builtin.Int1, -1
+  %20 = builtin "sadd_with_overflow_Int32"(%4 : $Builtin.Int32, %10 : $Builtin.Int32, %19 : $Builtin.Int1) : $(Builtin.Int32, Builtin.Int1)
+  %21 = tuple_extract %20 : $(Builtin.Int32, Builtin.Int1), 0
+  br bb1(%21 : $Builtin.Int32)
+
+bb3:
+  %23 = struct $Int32 (%4 : $Builtin.Int32)
+  return %23 : $Int32
+}
+
 /// Don't hoist arrays that are variant.
 // HOIST-LABEL: dont_hoist_variant_array
 // HOIST: bb0
@@ -1618,3 +1732,35 @@ bb3:
   return %25 : $Int32
 }
 
+
+// CHECK-LABEL: sil [ossa] @constant_indvar_sge_condition :
+// CHECK:         [[FALSE:%.*]] = integer_literal $Builtin.Int1, 0 
+// CHECK:         cond_fail [[FALSE]] : $Builtin.Int1, "Index out of bounds"
+// CHECK:       } // end sil function 'constant_indvar_sge_condition'
+sil [ossa] @constant_indvar_sge_condition : $@convention(thin) (Builtin.Int64) -> () {
+bb0(%0 : $Builtin.Int64):
+  %1 = integer_literal $Builtin.Int64, 0
+  %2 = integer_literal $Builtin.Int64, 1
+  %3 = integer_literal $Builtin.Int1, -1
+  br bb1(%1)
+
+
+bb1(%5 : $Builtin.Int64):
+  %6 = builtin "cmp_sge_Int64"(%5, %0) : $Builtin.Int1
+  cond_fail %6, "Index out of bounds"
+  %8 = builtin "sadd_with_overflow_Int64"(%5, %2, %3) : $(Builtin.Int64, Builtin.Int1)
+  %9 = tuple_extract %8, 0
+  %10 = tuple_extract %8, 1
+  cond_fail %10, "arithmetic overflow"
+  %12 = builtin "cmp_eq_Int64"(%9, %0) : $Builtin.Int1
+  cond_br %12, bb3, bb2
+
+bb2:
+  br bb1(%9)
+
+bb3:
+  %15 = tuple ()
+  return %15
+}
+
+
diff --git a/test/SILOptimizer/access_marker_verify.swift b/test/SILOptimizer/access_marker_verify.swift
index b4e47c86bc027..e496a33828af2 100644
--- a/test/SILOptimizer/access_marker_verify.swift
+++ b/test/SILOptimizer/access_marker_verify.swift
@@ -498,7 +498,7 @@ func accessOptionalArray(_ dict : MyDict<Int, [Int]>) {
 // CHECK:   store %{{.*}} to [trivial]
 // ----- Call MyDict.subscript.getter.
 // CHECK-NOT: begin_access
-// CHECK:   apply %{{.*}}<Int, [Int]>
+// CHECK:   apply %{{.*}}<Int, Array<Int>>
 // ----- access the temporary array result of the getter
 // CHECK:   [[TEMPACCESS:%.*]] = begin_access [modify] [unsafe] [[TEMP]]
 // CHECK:   [[HAS_VALUE:%.*]] = select_enum_addr [[TEMPACCESS]]
@@ -518,7 +518,7 @@ func accessOptionalArray(_ dict : MyDict<Int, [Int]>) {
 // CHECK:   alloc_stack $Int
 // CHECK:   store %{{.*}} to [trivial]
 // ----- call MyDict.subscript.setter
-// CHECK: apply %{{.*}}<Int, [Int]>([[ARRAYCOPY]], %{{.*}}, [[BOXACCESS]]) : $@convention(method) <τ_0_0, τ_0_1 where τ_0_0 : Hashable> (@in Optional<τ_0_1>, @in τ_0_0, @inout MyDict<τ_0_0, τ_0_1>) -> ()
+// CHECK: apply %{{.*}}<Int, Array<Int>>([[ARRAYCOPY]], %{{.*}}, [[BOXACCESS]]) : $@convention(method) <τ_0_0, τ_0_1 where τ_0_0 : Hashable> (@in Optional<τ_0_1>, @in τ_0_0, @inout MyDict<τ_0_0, τ_0_1>) -> ()
 // CHECK:   br [[RETBB:bb[0-9]+]]
 //
 // CHECK: [[FALSEBB]]:
@@ -530,7 +530,7 @@ func accessOptionalArray(_ dict : MyDict<Int, [Int]>) {
 // CHECK-NOT: begin_access
 // CHECK:   store %{{.*}} to [trivial] [[TEMP3]] : $*Int
 // Call MyDict.subscript.setter
-// CHECK:   apply %{{.*}}<Int, [Int]>([[WRITEBACK]], [[TEMP3]], [[BOXACCESS]]) : $@convention(method) <τ_0_0, τ_0_1 where τ_0_0 : Hashable> (@in Optional<τ_0_1>, @in τ_0_0, @inout MyDict<τ_0_0, τ_0_1>) -> ()
+// CHECK:   apply %{{.*}}<Int, Array<Int>>([[WRITEBACK]], [[TEMP3]], [[BOXACCESS]]) : $@convention(method) <τ_0_0, τ_0_1 where τ_0_0 : Hashable> (@in Optional<τ_0_1>, @in τ_0_0, @inout MyDict<τ_0_0, τ_0_1>) -> ()
 // CHECK:   end_access [[TEMPACCESS]] : $*Optional<Array<Int>>
 // CHECK:   end_access [[BOXACCESS]] : $*MyDict<Int, Array<Int>>
 // CHECK:   br [[RETBB]]
@@ -618,11 +618,15 @@ func testShims() -> UInt32 {
 }
 // CHECK-LABEL: sil hidden [ossa] @$s20access_marker_verify9testShimss6UInt32VyF : $@convention(thin) () -> UInt32 {
 // CHECK: bb0:
-// CHECK:   [[GA:%.*]] = global_addr @_SwiftKeyPathBufferHeader_SizeMask : $*UInt32
-// CHECK-NOT: begin_access
-// CHECK:   load [trivial] [[GA]] : $*UInt32
-// CHECK:   return
+// CHECK:   [[FR:%.*]] = function_ref @$sSo34_SwiftKeyPathBufferHeader_SizeMasks6UInt32Vvg : $@convention(thin) () -> UInt32
+// CHECK:   [[AP:%.*]] = apply [[FR]]() : $@convention(thin) () -> UInt32
+// CHECK:   return [[AP]]
 // CHECK-LABEL: } // end sil function '$s20access_marker_verify9testShimss6UInt32VyF'
+// CHECK: sil shared [transparent] [serialized] [ossa] @$sSo34_SwiftKeyPathBufferHeader_SizeMasks6UInt32Vvg : $@convention(thin) () -> UInt32 {
+// CHECK: bb0:
+// CHECK:   integer_literal $Builtin.IntLiteral, 16777215
+// CHECK: } // end sil function '$sSo34_SwiftKeyPathBufferHeader_SizeMasks6UInt32Vvg'
+
 
 // --- global variable initialization.
 var globalString1 = "⓪" // start non-empty
diff --git a/test/SILOptimizer/accessutils.sil b/test/SILOptimizer/accessutils.sil
index a098496ceea7f..a3381efc51b99 100644
--- a/test/SILOptimizer/accessutils.sil
+++ b/test/SILOptimizer/accessutils.sil
@@ -27,6 +27,10 @@ struct Ptr {
   var p: Int64
 }
 
+struct VectorStruct {
+  var a: Builtin.FixedArray<100, Int64>
+}
+
 class C {}
 
 sil @_getC : $@convention(thin) () -> @owned C
@@ -707,3 +711,20 @@ bb0(%0 : @guaranteed $List):
   return %6 : $Int64
 }
 
+// CHECK-LABEL: Accesses for vectors
+// CHECK:       Value:   %4 = index_addr %2 : $*Int64, %3 : $Builtin.Int64
+// CHECK-NEXT:    Scope: base
+// CHECK-NEXT:    Base: argument - %0 = argument of bb0 : $*VectorStruct
+// CHECK-NEXT:    Path: "s0.b.i5"
+// CHECK-NEXT:     no Storage paths
+// CHECK-LABEL: End accesses for vectors
+sil [ossa] @vectors : $@convention(thin) (@in_guaranteed VectorStruct) -> Int64 {
+bb0(%0 : $*VectorStruct):
+  %1 = struct_element_addr %0, #VectorStruct.a
+  %2 = vector_base_addr %1
+  %3 = integer_literal $Builtin.Int64, 5
+  %4 = index_addr %2, %3
+  %5 = load [trivial] %4
+  return %5
+}
+
diff --git a/test/SILOptimizer/addr_escape_info.sil b/test/SILOptimizer/addr_escape_info.sil
index f9b0e4cd64057..418277d88407b 100644
--- a/test/SILOptimizer/addr_escape_info.sil
+++ b/test/SILOptimizer/addr_escape_info.sil
@@ -1,4 +1,10 @@
-// RUN: %target-sil-opt %s -dump-addr-escape-info -o /dev/null | %FileCheck %s
+// RUN: %target-sil-opt %s -dump-addr-escape-info -o /dev/null \
+// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature AddressableTypes \
+// RUN: | %FileCheck %s
+
+// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_AddressableTypes
 
 // REQUIRES: swift_in_compiler
 
@@ -17,6 +23,12 @@ class X {
   @_hasStorage var s: Str
 }
 
+struct NonCopyable: ~Copyable {
+  var a: Int
+
+  deinit
+}
+
 class D: X {}
 
 struct Container {
@@ -37,8 +49,16 @@ protocol P {}
 
 extension Int : P {}
 
+@_addressableForDependencies
+struct Addressable {
+  @_hasStorage var a: Int
+}
+
+struct NE : ~Escapable {}
+
 sil @no_arguments : $@convention(thin) () -> ()
 sil @indirect_argument : $@convention(thin) (@in Int) -> ()
+sil @consume_nc : $@convention(thin) (@in NonCopyable) -> ()
 sil @indirect_struct_argument : $@convention(thin) (@in Str) -> ()
 sil @direct_argument : $@convention(thin) (Int) -> ()
 sil @class_argument : $@convention(thin) (@guaranteed X) -> ()
@@ -69,6 +89,14 @@ sil @modifyStr : $@convention(method) (@inout Str) -> ()
 sil @guaranteed_yield_coroutine : $@yield_once @convention(thin) (@inout X) -> @yields @inout X
 sil @in_ptr : $@convention(thin) (@in Builtin.RawPointer) -> ()
 
+sil @addressable_independent_arg : $@convention(thin) (@in_guaranteed Addressable) -> Builtin.RawPointer
+
+sil @addressable_dependent_arg : $@convention(thin) (@in_guaranteed Addressable) -> @lifetime(borrow address_for_deps 0) @owned NE
+
+sil @addressable_noescape_arg : $@convention(thin) (@in_guaranteed Addressable) -> @lifetime(borrow address_for_deps 0) @owned NE {
+[%0: noescape]
+}
+
 // CHECK-LABEL: Address escape information for test_simple:
 // CHECK:       value:  %1 = struct_element_addr %0 : $*Str, #Str.a
 // CHECK-NEXT:    ==>   %7 = apply %6(%5) : $@convention(thin) (@in Int) -> ()
@@ -849,7 +877,7 @@ bb2(%17 : $Error):
 }
 
 // CHECK-LABEL: Address escape information for test_store_borrow:
-// CHECK:       value:  %2 = store_borrow %0 to %1 : $*X                // users: %4, %3
+// CHECK:       value:  %2 = store_borrow %0 to %1 : $*X
 // CHECK-NEXT:  End function test_store_borrow
 sil [ossa] @test_store_borrow : $@convention(thin) (@guaranteed X) -> () {
 bb0(%0 :  @guaranteed $X):
@@ -862,3 +890,115 @@ bb0(%0 :  @guaranteed $X):
   return %3 : $()
 }
 
+// CHECK-LABEL: Address escape information for test_drop_deinit:
+// CHECK:       value:  %1 = alloc_stack $NonCopyable
+// CHECK-NEXT:    -     %6 = apply %5() : $@convention(thin) () -> ()
+// CHECK-NEXT:    ==>   %8 = apply %7(%3) : $@convention(thin) (@in NonCopyable) -> ()
+// CHECK-NEXT:  End function test_drop_deinit
+sil [ossa] @test_drop_deinit : $@convention(thin) (@owned NonCopyable) -> () {
+bb0(%0 :  @owned $NonCopyable):
+  %1 = alloc_stack $NonCopyable
+  store %0 to [init] %1
+  %3 = drop_deinit %1
+  fix_lifetime %1
+  %5 = function_ref @no_arguments : $@convention(thin) () -> ()
+  %6 = apply %5() : $@convention(thin) () -> ()
+  %7 = function_ref @consume_nc : $@convention(thin) (@in NonCopyable) -> ()
+  %8 = apply %7(%3) : $@convention(thin) (@in NonCopyable) -> ()
+  dealloc_stack %1
+  %10 = tuple ()
+  return %10 : $()
+}
+
+// CHECK-LABEL: Address escape information for noescape_via_independent_addressable:
+// CHECK: pair 0 - 1
+// CHECK-NEXT: apply %{{.*}}(%{{.*}}) : $@convention(thin) (@in_guaranteed Addressable) -> Builtin.RawPointer
+// CHECK-NEXT: alloc_stack $Addressable
+// CHECK-NEXT: no alias
+// CHECK-LABEL: End function noescape_via_independent_addressable
+sil [ossa] @noescape_via_independent_addressable : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = alloc_stack $Addressable
+  %2 = struct_element_addr %1 : $*Addressable, #Addressable.a
+  store %0 to [trivial] %2
+
+  %f = function_ref @addressable_independent_arg : $@convention(thin) (@in_guaranteed Addressable) -> Builtin.RawPointer
+  %a = apply %f(%1) : $@convention(thin) (@in_guaranteed Addressable) -> Builtin.RawPointer
+
+  fix_lifetime %a
+  fix_lifetime %1
+  destroy_addr %1
+  dealloc_stack %1
+
+  %9 = tuple ()
+  return %9 : $()
+}
+
+// CHECK-LABEL: Address escape information for escape_via_dependent_addressable:
+// CHECK: pair 0 - 1
+// CHECK-NEXT:   %{{.*}} = apply %{{.*}}(%{{.*}}) : $@convention(thin) (@in_guaranteed Addressable) -> @lifetime(borrow address_for_deps 0) @owned NE
+// CHECK-NEXT:   %{{.*}} = alloc_stack $Addressable
+// CHECK-NEXT: may alias
+// CHECK-LABEL: End function escape_via_dependent_addressable
+sil [ossa] @escape_via_dependent_addressable : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = alloc_stack $Addressable
+  %2 = struct_element_addr %1 : $*Addressable, #Addressable.a
+  store %0 to [trivial] %2
+
+  %f = function_ref @addressable_dependent_arg : $@convention(thin) (@in_guaranteed Addressable) -> @lifetime(borrow address_for_deps 0) @owned NE
+  %a = apply %f(%1) : $@convention(thin) (@in_guaranteed Addressable) -> @lifetime(borrow address_for_deps 0) @owned NE
+
+  fix_lifetime %a
+  fix_lifetime %1
+  destroy_value %a
+  destroy_addr %1
+  dealloc_stack %1
+
+  %9 = tuple ()
+  return %9 : $()
+}
+
+// CHECK-LABEL: Address escape information for escape_via_noescape_addressable:
+// CHECK: pair 0 - 1
+// CHECK-NEXT:   %{{.*}} = apply %{{.*}}(%{{.*}}) : $@convention(thin) (@in_guaranteed Addressable) -> @lifetime(borrow address_for_deps 0) @owned NE
+// CHECK-NEXT:   %{{.*}} = alloc_stack $Addressable
+// CHECK-NEXT: no alias
+// CHECK-LABEL: End function escape_via_noescape_addressable
+sil [ossa] @escape_via_noescape_addressable : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = alloc_stack $Addressable
+  %2 = struct_element_addr %1 : $*Addressable, #Addressable.a
+  store %0 to [trivial] %2
+
+  %f = function_ref @addressable_noescape_arg : $@convention(thin) (@in_guaranteed Addressable) -> @lifetime(borrow address_for_deps 0) @owned NE
+  %a = apply %f(%1) : $@convention(thin) (@in_guaranteed Addressable) -> @lifetime(borrow address_for_deps 0) @owned NE
+
+  fix_lifetime %a
+  fix_lifetime %1
+  destroy_value %a
+  destroy_addr %1
+  dealloc_stack %1
+
+  %9 = tuple ()
+  return %9 : $()
+}
+
+// CHECK-LABEL: Address escape information for escaping_pointer_through_function:
+// CHECK:       value:  %1 = alloc_stack $Int
+// CHECK-NEXT:    ==>   %4 = apply undef(%3) : $@convention(thin) (Builtin.RawPointer) -> UnsafeMutableRawBufferPointer
+// CHECK-NEXT:    ==>   %5 = apply undef(%4) : $@convention(thin) (UnsafeMutableRawBufferPointer) -> ()
+// CHECK-NEXT:  End function escaping_pointer_through_function
+sil [ossa] @escaping_pointer_through_function : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = alloc_stack $Int
+  fix_lifetime %1
+  %3 = address_to_pointer %1 to $Builtin.RawPointer
+  %4 = apply undef(%3) : $@convention(thin) (Builtin.RawPointer) -> UnsafeMutableRawBufferPointer
+  %5 = apply undef(%4) : $@convention(thin) (UnsafeMutableRawBufferPointer) -> ()
+  dealloc_stack %1
+  %7 = tuple ()
+  return %7
+}
+
+
diff --git a/test/SILOptimizer/address_lowering.sil b/test/SILOptimizer/address_lowering.sil
index d863ec0b932f6..6ce6bc53a62aa 100644
--- a/test/SILOptimizer/address_lowering.sil
+++ b/test/SILOptimizer/address_lowering.sil
@@ -29,6 +29,8 @@ enum Optional<T> {
 
 protocol Error {}
 
+struct Bad: Error {}
+
 struct I {}
 
 class Klass {}
@@ -107,6 +109,10 @@ sil [ossa] @takeGuaranteedObject : $@convention(thin) (@guaranteed AnyObject) ->
 sil [ossa] @takeIndirectClass : $@convention(thin) (@in_guaranteed C) -> ()
 sil [ossa] @takeTuple : $@convention(thin) <τ_0_0> (@in_guaranteed (τ_0_0, C)) -> ()
 
+sil [ossa] @eraseToAny : $@convention(thin) <T> (@in_guaranteed T) -> @out Any
+sil [ossa] @produceInt : $@convention(thin) () -> Int
+sil [ossa] @produceBool : $@convention(thin) () -> Bool
+sil [ossa] @produceBad : $@convention(thin) () -> Bad
 
 sil [ossa] @takeIn : $@convention(thin) <T> (@in T) -> ()
 sil [ossa] @takeInGuaranteed : $@convention(thin) <T> (@in_guaranteed T) -> ()
@@ -1452,6 +1458,142 @@ bad(%41 : @owned $any Error):
   throw %41 : $any Error
 }
 
+// While an '@error Error' turns into an '@error any Error', an '@error' of a concrete type remains as-is.
+// --------
+// CHECK-LABEL: sil [ossa] @f270_typedThrows_throwConcrete : $@convention(thin) (Bad) -> (Bad, @error Bad) {
+// CHECK:       bb0(%0 : $Bad):
+// CHECK:         return %0 : $Bad
+// CHECK:         throw %0 : $Bad
+// CHECK-LABEL: } // end sil function 'f270_typedThrows_throwConcrete'
+sil [ossa] @f270_typedThrows_throwConcrete : $@convention(thin) (Bad) -> (Bad, @error Bad) {
+bb0(%0 : $Bad):
+  %fn = function_ref @produceBool : $@convention(thin) () -> Bool
+  %cond = apply %fn() : $@convention(thin) () -> Bool
+  cond_br %cond, doThrow, doReturn
+
+doThrow:
+  throw %0
+
+doReturn:
+  return %0
+}
+
+// CHECK-LABEL: sil [ossa] @f271_typedThrows_callConcrete : $@convention(thin) () -> () {
+// CHECK:         try_apply {{.*}} : $@convention(thin) (Bad) -> (Bad, @error Bad), normal bb2, error bb1
+// CHECK:         bb1({{.*}} : $Bad)
+// CHECK:         bb2({{.*}} : $Bad)
+// CHECK-LABEL: } // end sil function 'f271_typedThrows_callConcrete'
+sil [ossa] @f271_typedThrows_callConcrete : $@convention(thin) () -> () {
+bb0:
+  %fn = function_ref @produceBad : $@convention(thin) () -> Bad
+  %arg = apply %fn() : $@convention(thin) () -> Bad
+  %callee = function_ref @f270_typedThrows_throwConcrete : $@convention(thin) (Bad) -> (Bad, @error Bad)
+  try_apply %callee(%arg) : $@convention(thin) (Bad) -> (Bad, @error Bad), normal normalBB, error errorBB
+
+normalBB(%r : $Bad):
+  ignored_use %r
+  br exitBB
+
+errorBB(%e : $Bad):
+  ignored_use %e
+  br exitBB
+
+exitBB:
+  %t = tuple ()
+  return %t
+}
+
+// Handle throwing a generic type conforming to Error via @error_indirect
+// --------
+// CHECK-LABEL: sil [ossa] @f272_typedThrows_throwGeneric : $@convention(thin) <GenBad, Result where GenBad : Error> (@in_guaranteed GenBad, @in_guaranteed Result) -> (@out Result, @error_indirect GenBad) {
+// CHECK:       bb0(%0 : $*Result, %1 : $*GenBad, %2 : $*GenBad, %3 : $*Result):
+// CHECK:         cond_br {{.*}}, bb2, bb1
+//
+// CHECK:       bb1:
+// CHECK:         copy_addr %3 to [init] %0 : $*Result
+// CHECK:         return {{.*}} : $()
+//
+// CHECK:       bb2:
+// CHECK:         [[STACK:%[^,]+]] = alloc_stack $GenBad
+// CHECK:         copy_addr %2 to [init] [[STACK]] : $*GenBad
+// CHECK:         copy_addr [take] [[STACK]] to [init] %1 : $*GenBad
+// CHECK:         dealloc_stack [[STACK]] : $*GenBad
+// CHECK:         throw_addr
+// CHECK-LABEL: } // end sil function 'f272_typedThrows_throwGeneric'
+sil [ossa] @f272_typedThrows_throwGeneric : $@convention(thin) <GenBad, Result where GenBad : Error> (@in_guaranteed GenBad, @in_guaranteed Result) -> (@out Result, @error_indirect GenBad) {
+bb0(%e : @guaranteed $GenBad, %r : @guaranteed $Result):
+  %fn = function_ref @produceBool : $@convention(thin) () -> Bool
+  %cond = apply %fn() : $@convention(thin) () -> Bool
+  cond_br %cond, doThrow, doReturn
+
+doReturn:
+  %rCopy = copy_value %r
+  return %rCopy
+
+doThrow:
+  %eCopy = copy_value %e
+  throw %eCopy
+}
+
+// CHECK-LABEL:  sil [ossa] @f273_typedThrows_callGeneric : $@convention(thin) () -> () {
+// CHECK:        bb0:
+// CHECK:          // function_ref produceBad
+// CHECK:          [[PROD:%[^,]+]] = function_ref @produceBad : $@convention(thin) () -> Bad
+// CHECK:          [[ARG1:%[^,]+]] = apply [[PROD]]() : $@convention(thin) () -> Bad
+// CHECK:          [[ARG2:%[^,]+]] = apply [[PROD]]() : $@convention(thin) () -> Bad
+// CHECK:          [[ARG1_IN:%[^,]+]] = alloc_stack $Bad
+// CHECK:          store [[ARG1]] to [trivial] [[ARG1_IN]] : $*Bad
+// CHECK:          [[ARG2_IN:%[^,]+]] = alloc_stack $Bad
+// CHECK:          store [[ARG2]] to [trivial] [[ARG2_IN]] : $*Bad
+// CHECK:          [[RESULT_OUT:%[^,]+]] = alloc_stack $Bad
+// CHECK:          [[ERR_OUT:%[^,]+]] = alloc_stack $Bad
+// CHECK:          try_apply {{.*}}<Bad, Bad>([[RESULT_OUT]], [[ERR_OUT]], [[ARG1_IN]], [[ARG2_IN]]) : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 : Error> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_1) -> (@out τ_0_1, @error_indirect τ_0_0), normal bb2, error bb1
+
+// CHECK:        bb1:
+// CHECK:          [[ERR:%[^,]+]] = load [trivial] [[ERR_OUT]] : $*Bad
+// CHECK:          dealloc_stack [[ERR_OUT]] : $*Bad
+// CHECK:          dealloc_stack [[RESULT_OUT]] : $*Bad
+// CHECK:          dealloc_stack [[ARG2_IN]] : $*Bad
+// CHECK:          dealloc_stack [[ARG1_IN]] : $*Bad
+// CHECK:          ignored_use [[ERR]] : $Bad
+// CHECK:          ignored_use [[ERR]] : $Bad
+// CHECK:          br bb3
+
+// CHECK:        bb2(%11 : $()):
+// CHECK:          dealloc_stack [[ERR_OUT]] : $*Bad
+// CHECK:          [[RESULT:%[^,]+]] = load [trivial] [[RESULT_OUT]] : $*Bad
+// CHECK:          dealloc_stack [[RESULT_OUT]] : $*Bad
+// CHECK:          dealloc_stack [[ARG2_IN]] : $*Bad
+// CHECK:          dealloc_stack [[ARG1_IN]] : $*Bad
+// CHECK:          ignored_use [[RESULT]] : $Bad
+// CHECK:          br bb3
+
+// CHECK:        bb3:
+// CHECK:          return {{.*}} : $()
+// CHECK-LABEL:  } // end sil function 'f273_typedThrows_callGeneric'
+sil [ossa] @f273_typedThrows_callGeneric : $@convention(thin) () -> () {
+bb0:
+  %fn = function_ref @produceBad : $@convention(thin) () -> Bad
+  %arg1 = apply %fn() : $@convention(thin) () -> Bad
+  %arg2 = apply %fn() : $@convention(thin) () -> Bad
+  %callee = function_ref @f272_typedThrows_throwGeneric : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 : Error> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_1) -> (@out τ_0_1, @error_indirect τ_0_0)
+  try_apply %callee<Bad, Bad>(%arg1, %arg2) : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 : Error> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_1) -> (@out τ_0_1, @error_indirect τ_0_0), normal normalBB, error errorBB
+
+normalBB(%r : $Bad):
+  ignored_use %r
+  br exitBB
+
+errorBB(%e : $Bad):
+  ignored_use %e
+  ignored_use %e
+  br exitBB
+
+exitBB:
+  %t = tuple ()
+  return %t
+}
+
+
 // CHECK-LABEL: sil [ossa] @fixeeLifetime : {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[ADDR:%[^,]+]] : $*T):
 // CHECK:         fix_lifetime [[ADDR]]
@@ -2555,6 +2697,32 @@ bb0:
   return %retval : $()
 }
 
+// Verify that ignored_use of an address-only type gets lowered correctly.
+// CHECK-LABEL: sil [ossa] @test_ignored_use : $@convention(thin) () -> () {
+// CHECK:          [[RETVAL_ADDR:%[^,]+]] = alloc_stack $Any
+// CHECK:          [[MAKE_INT:%[^,]+]] = function_ref @produceInt : $@convention(thin) () -> Builtin.Int64
+// CHECK:          [[INT:%[^,]+]] = apply [[MAKE_INT]]()
+// CHECK:          [[ERASE_FN:%[^,]+]] = function_ref @eraseToAny : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> @out Any
+// CHECK:          [[ARG_ADDR:%[^,]+]] = alloc_stack $Builtin.Int64
+// CHECK:          store [[INT]] to [trivial] [[ARG_ADDR]] : $*Builtin.Int64
+// CHECK:          = apply [[ERASE_FN]]<Builtin.Int64>([[RETVAL_ADDR]], [[ARG_ADDR]]) : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> @out Any
+// CHECK:          dealloc_stack [[ARG_ADDR]] : $*Builtin.Int64
+// CHECK:          ignored_use [[RETVAL_ADDR]] : $*Any
+// CHECK:          destroy_addr [[RETVAL_ADDR]] : $*Any
+// CHECK:          dealloc_stack [[RETVAL_ADDR]] : $*Any
+// CHECK:       } // end sil function 'test_ignored_use'
+sil [ossa] @test_ignored_use : $@convention(thin) () -> () {
+bb0:
+  %1 = function_ref @produceInt : $@convention(thin) () -> Int
+  %2 = apply %1() : $@convention(thin) () -> Int
+  %3 = function_ref @eraseToAny : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> @out Any
+  %4 = apply %3<Int>(%2) : $@convention(thin) <τ_0_0> (@in_guaranteed τ_0_0) -> @out Any
+  ignored_use %4
+  destroy_value %4
+  %5 = tuple ()
+  return %5
+}
+
 // CHECK-LABEL: sil [ossa] @test_mark_unresolved_non_copyable_value_1_consumable_and_assignable : {{.*}} {
 // CHECK:       bb0([[T:%[^,]+]] :
 // CHECK:         [[TP:%[^,]+]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[T]]
diff --git a/test/SILOptimizer/addressable_dependencies.swift b/test/SILOptimizer/addressable_dependencies.swift
index 2b05f43d757db..7332ec0d81d09 100644
--- a/test/SILOptimizer/addressable_dependencies.swift
+++ b/test/SILOptimizer/addressable_dependencies.swift
@@ -1,25 +1,17 @@
-// RUN: %target-swift-frontend -emit-sil -enable-experimental-feature BuiltinModule -enable-experimental-feature LifetimeDependence -enable-experimental-feature AddressableTypes %s | %FileCheck %s
+// RUN: %target-swift-frontend -emit-sil -enable-experimental-feature BuiltinModule -enable-experimental-feature Lifetimes -enable-experimental-feature AddressableTypes %s | %FileCheck %s
 
 // REQUIRES: swift_feature_BuiltinModule
 // REQUIRES: swift_feature_AddressableTypes
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 import Builtin
 
-// Copied from the stdlib until we have Builtin.overrideLifetime.
-@_unsafeNonescapableResult
-@lifetime(borrow source)
-internal func _overrideLifetime<T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable>(
-  _ dependent: consuming T, borrowing source: borrowing U) -> T {
-  dependent
-}
-
 struct NodeRef: ~Escapable {
     private var parent: UnsafePointer<Node>
 
     // CHECK-LABEL: sil {{.*}}@${{.*}}7NodeRefV4node{{.*}}fC :
     // CHECK-SAME:    (@in_guaranteed Node,
-    @lifetime(borrow node)
+    @_lifetime(borrow node)
     init(node: borrowing Node) {
         // CHECK: bb0(%0 : @noImplicitCopy $*Node,
         // CHECK:   [[RAW_PTR:%.*]] = address_to_pointer {{.*}}%0
@@ -29,7 +21,7 @@ struct NodeRef: ~Escapable {
 
     // CHECK-LABEL: sil {{.*}}@${{.*}}7NodeRefV9allocated{{.*}}fC :
     // CHECK-SAME:    (@guaranteed AllocatedNode,
-    @lifetime(borrow allocated)
+    @_lifetime(borrow allocated)
     init(allocated: borrowing AllocatedNode) {
         self.parent = allocated.node
     }
@@ -42,7 +34,7 @@ struct Node {
     var ref: NodeRef {
       // CHECK-LABEL: sil {{.*}}@${{.*}}4NodeV3ref{{.*}}Vvg :
       // CHECK-SAME:    (@in_guaranteed Node) ->
-      @lifetime(borrow self)
+      @_lifetime(borrow self)
       borrowing get {
         // CHECK: bb0(%0 : @noImplicitCopy $*Node):
         // CHECK: [[REF:%.*]] = apply {{.*}}(%0,
@@ -59,7 +51,7 @@ struct AllocatedNode: ~Copyable {
     var ref: NodeRef {
       // CHECK-LABEL: sil {{.*}}@${{.*}}13AllocatedNodeV3ref{{.*}}Vvg :
       // CHECK-SAME:    (@guaranteed AllocatedNode) ->
-      @lifetime(borrow self)
+      @_lifetime(borrow self)
       borrowing get {
         return NodeRef(allocated: self)
       }
@@ -74,7 +66,7 @@ struct Schmector {
     var storage: Spam {
         // CHECK-LABEL: sil {{.*}}@${{.*}}9SchmectorV7storage{{.*}}Vvg :
         // CHECK-SAME:    (@in_guaranteed Schmector) ->
-        @lifetime(borrow self)
+        @_lifetime(borrow self)
         borrowing get {
             let pointer = UnsafePointer<Int>(Builtin.addressOfBorrow(self))
             let spam = Spam(base: pointer, count: 10)
@@ -84,6 +76,6 @@ struct Schmector {
 }
 
 struct Spam: ~Escapable {
-    @lifetime(borrow base)
+    @_lifetime(borrow base)
     init(base: UnsafePointer<Int>, count: Int) {}
 }
diff --git a/test/SILOptimizer/addressable_dependency_optimization.swift b/test/SILOptimizer/addressable_dependency_optimization.swift
new file mode 100644
index 0000000000000..3d5cb4cccfda7
--- /dev/null
+++ b/test/SILOptimizer/addressable_dependency_optimization.swift
@@ -0,0 +1,24 @@
+// RUN: %target-swift-frontend -emit-sil -parse-as-library -O -module-name=test \
+// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature AddressableTypes \
+// RUN:   %s | %FileCheck %s
+
+// REQUIRES: swift_feature_AddressableTypes
+// REQUIRES: swift_feature_LifetimeDependence
+
+// Enable this test as soon as CollectionOfOne is marked @_addressableForDependencies.
+// REQUIRES: rdar145687827
+
+// CHECK-LABEL: sil {{.*}}@$s4test0A10OneIntSpan1cs0D0VySiGs012CollectionOfB0VySiG_tF : $@convention(thin) (@in_guaranteed CollectionOfOne<Int>) -> @lifetime(borrow address_for_deps 0) @owned Span<Int> {
+// CHECK: bb0(%0 : $*CollectionOfOne<Int>):
+// CHECK:   [[RP:%.*]] = address_to_pointer {{.*}}%0 to $Builtin.RawPointer
+// CHECK:   [[UP:%.*]] = struct $UnsafeRawPointer ([[RP]])
+// CHECK:   [[OP:%.*]] = enum $Optional<UnsafeRawPointer>, #Optional.some!enumelt, [[UP]]
+// CHECK:   [[SPAN:%.*]] = struct $Span<Int> ([[OP]]
+// CHECK:   return [[SPAN]]
+// CHECK-LABEL: } // end sil function '$s4test0A10OneIntSpan1cs0D0VySiGs012CollectionOfB0VySiG_tF'
+@available(SwiftStdlib 6.2, *)
+@lifetime(borrow c)
+public func testOneIntSpan(c: CollectionOfOne<Int>) -> Span<Int> {
+  c.span
+}
diff --git a/test/SILOptimizer/addressable_move_only_checking.swift b/test/SILOptimizer/addressable_move_only_checking.swift
index 3131b4342b8ad..26c9740507a63 100644
--- a/test/SILOptimizer/addressable_move_only_checking.swift
+++ b/test/SILOptimizer/addressable_move_only_checking.swift
@@ -1,9 +1,9 @@
-// RUN: %target-swift-frontend -emit-sil -enable-experimental-feature BuiltinModule -enable-experimental-feature LifetimeDependence -enable-experimental-feature AddressableTypes -enable-experimental-feature AddressableParameters -verify %s
+// RUN: %target-swift-frontend -emit-sil -enable-experimental-feature BuiltinModule -enable-experimental-feature Lifetimes -enable-experimental-feature AddressableTypes -enable-experimental-feature AddressableParameters -verify %s
 
 // REQUIRES: swift_feature_BuiltinModule
 // REQUIRES: swift_feature_AddressableParameters
 // REQUIRES: swift_feature_AddressableTypes
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 @_addressableForDependencies
 struct Node {
@@ -15,14 +15,14 @@ struct Node {
 struct NodeRef: ~Escapable {
     private var parent: UnsafePointer<Node>
 
-    @lifetime(borrow node)
+    @_lifetime(borrow node)
     init(node: borrowing Node) { fatalError() }
 }
 
 // Ensure there aren't spurious errors about consumption when an addressable
 // parameter is passed as a normal loadable parameter to another function
 // or method.
-@lifetime(borrow node)
+@_lifetime(borrow node)
 func test(node: borrowing Node) -> NodeRef {
     node.grungle()
     return NodeRef(node: node)
diff --git a/test/SILOptimizer/alias-analysis.sil b/test/SILOptimizer/alias-analysis.sil
index 19e8e72fa82fc..d9cd41613fd39 100644
--- a/test/SILOptimizer/alias-analysis.sil
+++ b/test/SILOptimizer/alias-analysis.sil
@@ -99,3 +99,44 @@ bb0(%0 : $*MyStruct, %1 : $Builtin.Word):
   %99 = tuple ()
   return %99 : $()
 }
+
+// CHECK-LABEL: @testVectorBaseAddr
+// CHECK:       PAIR #18.
+// CHECK-NEXT:      %2 = vector_base_addr %0 : $*Builtin.FixedArray<10, Int>
+// CHECK-NEXT:      %3 = index_addr %2 : $*Int, %1 : $Builtin.Word
+// CHECK-NEXT:    MayAlias
+// CHECK:       PAIR #21.
+// CHECK-NEXT:      %2 = vector_base_addr %0 : $*Builtin.FixedArray<10, Int>
+// CHECK-NEXT:      %6 = index_addr %2 : $*Int, %4 : $Builtin.Word
+// CHECK-NEXT:    NoAlias
+// CHECK:       PAIR #22.
+// CHECK-NEXT:      %2 = vector_base_addr %0 : $*Builtin.FixedArray<10, Int>
+// CHECK-NEXT:      %7 = index_addr %2 : $*Int, %5 : $Builtin.Word
+// CHECK-NEXT:    NoAlias
+// CHECK:       PAIR #27.
+// CHECK-NEXT:      %3 = index_addr %2 : $*Int, %1 : $Builtin.Word
+// CHECK-NEXT:      %6 = index_addr %2 : $*Int, %4 : $Builtin.Word
+// CHECK-NEXT:    MayAlias
+// CHECK:       PAIR #28.
+// CHECK-NEXT:      %3 = index_addr %2 : $*Int, %1 : $Builtin.Word
+// CHECK-NEXT:      %7 = index_addr %2 : $*Int, %5 : $Builtin.Word
+// CHECK-NEXT:    MayAlias
+// CHECK:       PAIR #40.
+// CHECK-NEXT:      %6 = index_addr %2 : $*Int, %4 : $Builtin.Word
+// CHECK-NEXT:      %7 = index_addr %2 : $*Int, %5 : $Builtin.Word
+// CHECK-NEXT:    NoAlias
+sil @testVectorBaseAddr : $@convention(thin) (@inout Builtin.FixedArray<10, Int>, Builtin.Word) -> () {
+bb0(%0 : $*Builtin.FixedArray<10, Int>, %1 : $Builtin.Word):
+  %2 = vector_base_addr %0
+  %3 = index_addr %2, %1
+  %4 = integer_literal $Builtin.Word, 1
+  %5 = integer_literal $Builtin.Word, 2
+  %6 = index_addr %2, %4
+  %7 = index_addr %2, %5
+  fix_lifetime %2
+  fix_lifetime %3
+  fix_lifetime %6
+  fix_lifetime %7
+  %99 = tuple ()
+  return %99 : $()
+}
diff --git a/test/SILOptimizer/allocbox_to_stack.sil b/test/SILOptimizer/allocbox_to_stack.sil
index 5be2d84f663a5..26f568cf31549 100644
--- a/test/SILOptimizer/allocbox_to_stack.sil
+++ b/test/SILOptimizer/allocbox_to_stack.sil
@@ -14,6 +14,8 @@ struct Bool {
 
 protocol Error {}
 
+class C {}
+
 // CHECK-LABEL: sil @simple_promotion
 sil @simple_promotion : $(Int) -> Int {
 bb0(%0 : $Int):
@@ -125,10 +127,9 @@ bb1(%0 : $Int):
 
 sil @callee : $@convention(thin) (@inout Int) -> ()
 
-// CHECK-LABEL: sil @inout_nocapture
-sil @inout_nocapture : $@convention(thin) () -> Int {
+// CHECK-LABEL: sil @escaping_pointer
+sil @escaping_pointer : $@convention(thin) () -> Int {
 bb0:
-  // CHECK: alloc_stack
   %1 = alloc_box ${ var Int }
   %1a = project_box %1 : ${ var Int }, 0
   %6 = function_ref @callee : $@convention(thin) (@inout Int) -> ()
@@ -398,7 +399,7 @@ bb0(%0 : $Int):
 }
 
 // CHECK-LABEL: sil private @$s6struct8useStack1tySi_tFSiycfU_Tf0s_n
-// CHECK-LABEL: sil private [_semantics "sil.optimizer.delete_if_unused"] @$s6struct8useStack1tySi_tFSiycfU_
+// CHECK-LABEL: sil private @$s6struct8useStack1tySi_tFSiycfU_
 // struct.(useStack (t : Swift.Int) -> ()).(closure #1)
 sil private @$s6struct8useStack1tySi_tFSiycfU_ : $@convention(thin) (@owned <τ_0_0> { var τ_0_0 } <Int>) -> Int {
 bb0(%0 : $<τ_0_0> { var τ_0_0 } <Int>):
@@ -651,7 +652,7 @@ bb0(%0 : $Int, %1 : $*S<T>):
   return %9 : $Bool
 }
 
-// CHECK-LABEL: sil shared [_semantics "sil.optimizer.delete_if_unused"] @closure1
+// CHECK-LABEL: sil shared @closure1
 sil shared @closure1 : $@convention(thin) <T where T : Count> (Int, @owned <τ_0_0 : Count> { var S<τ_0_0> } <T>) -> Bool {
 // CHECK: bb0
 bb0(%0 : $Int, %1 : $<τ_0_0 where τ_0_0 : Count> { var S<τ_0_0> } <T>):
@@ -673,7 +674,7 @@ bb0(%0 : $Int, %1 : $<τ_0_0 where τ_0_0 : Count> { var S<τ_0_0> } <T>):
 // CHECK: return
 // CHECK-NOT: bb1
 
-// CHECK-LABEL: sil shared [_semantics "sil.optimizer.delete_if_unused"] @closure2
+// CHECK-LABEL: sil shared @closure2
 sil shared @closure2 : $@convention(thin) <T where T : Count> (Int, @owned <τ_0_0 : Count> { var S<τ_0_0> } <T>) -> Bool {
 // CHECK: bb0
 bb0(%0 : $Int, %1 : $<τ_0_0 where τ_0_0 : Count> { var S<τ_0_0> } <T>):
@@ -901,7 +902,6 @@ bb2:
 // CHECK:      bb1:
 // CHECK-NEXT:   [[STACK2:%[0-9]+]] = alloc_stack $Bool
 // CHECK-NEXT:   dealloc_stack [[STACK2]]
-// CHECK-NEXT:   dealloc_stack [[BOX]]
 // CHECK-NEXT:   unreachable
 // CHECK:      bb2:
 // CHECK:        store {{%[0-9]+}}
@@ -1059,10 +1059,8 @@ bb3:
 // CHECK-NEXT:   [[AI:%[0-9]+]] = alloc_stack $Int
 // CHECK-NEXT:   cond_br
 // CHECK:      bb1:
-// CHECK-NEXT:   dealloc_stack [[AI]]
 // CHECK-NEXT:   br bb3
 // CHECK:      bb2:
-// CHECK-NEXT:   dealloc_stack [[AI]]
 // CHECK-NEXT:   br bb3
 // CHECK:      bb3:
 // CHECK-NEXT:   store {{%[0-9]+}}
@@ -1226,3 +1224,201 @@ bb0:
   destroy_value %box : ${ var Builtin.Int32 }
   return %value : $Builtin.Int32
 }
+
+sil @getC : $@convention(thin) () -> (@owned C)
+
+// CHECK-LABEL: sil @leak_to_inf_loop_1 : {{.*}} {
+// CHECK-NOT:     destroy_addr
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'leak_to_inf_loop_1'
+sil @leak_to_inf_loop_1 : $@convention(thin) (@owned C) -> () {
+entry(%c : $C):
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  store %c to %c_addr
+  strong_retain %box
+  strong_release %box
+  br loop
+
+loop:
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c2 = apply %getC() : $@convention(thin) () -> (@owned C)
+  %c_old = load %c_addr
+  store %c2 to %c_addr
+  release_value %c_old
+  br loop
+}
+
+// CHECK-LABEL: sil @leak_to_inf_loop_2 : {{.*}} {
+// CHECK:         cond_br undef, [[EXIT:bb[0-9]+]], [[TO_LOOP:bb[0-9]+]]
+// CHECK:       [[EXIT]]
+// CHECK:         destroy_addr
+// CHECK:         dealloc_stack
+// CHECK:       [[TO_LOOP]]
+// CHECK-NOT:     destroy_addr
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'leak_to_inf_loop_2'
+sil @leak_to_inf_loop_2 : $@convention(thin) (@owned C) -> () {
+entry(%c : $C):
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  store %c to %c_addr
+  strong_retain %box
+  strong_release %box
+  cond_br undef, exit, to_loop
+
+exit:
+  strong_release %box
+  return undef : $()
+
+to_loop:
+  strong_retain %box
+  strong_release %box
+  br loop
+
+loop:
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c2 = apply %getC() : $@convention(thin) () -> (@owned C)
+  %c_old = load %c_addr
+  store %c2 to %c_addr
+  release_value %c_old
+  br loop
+}
+
+// CHECK-LABEL: sil @leak_to_inf_loop_3 : {{.*}} {
+// CHECK-NOT:     destroy_addr
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'leak_to_inf_loop_3'
+sil @leak_to_inf_loop_3 : $@convention(thin) (@owned C) -> () {
+entry(%c : $C):
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  store %c to %c_addr
+  br to_loop
+
+to_loop:
+  strong_retain %box
+  strong_release %box
+  br loop
+
+loop:
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c2 = apply %getC() : $@convention(thin) () -> (@owned C)
+  %c_old = load %c_addr
+  store %c2 to %c_addr
+  release_value %c_old
+  br loop
+}
+
+// CHECK-LABEL: sil @dealloc_box_before_loop
+// CHECK:         dealloc_stack
+// CHECK-LABEL: } // end sil function 'dealloc_box_before_loop'
+sil @dealloc_box_before_loop : $@convention(thin) (@owned C) -> () {
+entry(%c : $C):
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  store %c to %c_addr
+  cond_br undef, exit, to_loop
+
+exit:
+  strong_release %box
+  return undef : $()
+
+to_loop:
+  dealloc_box %box
+  br loop
+
+loop:
+  br loop
+}
+
+// CHECK-LABEL: sil @alloc_box_in_deadend_loop
+// CHECK:         alloc_stack
+// CHECK:         dealloc_stack
+// CHECK-LABEL: } // end sil function 'alloc_box_in_deadend_loop'
+sil @alloc_box_in_deadend_loop : $@convention(thin) () -> () {
+entry:
+  br loop
+
+loop:
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c = apply %getC() : $@convention(thin) () -> (@owned C)
+  store %c to %c_addr
+  strong_release %box
+  br loop
+}
+
+// CHECK-LABEL: sil @alloc_box_in_exiting_loop
+// CHECK:         br [[EXITING_LOOP:bb[0-9]+]]
+// CHECK:       [[EXITING_LOOP]]:
+// CHECK:         alloc_stack
+// CHECK:         cond_br undef, [[EXIT:bb[0-9]+]], [[LATCH:bb[0-9]+]]
+// CHECK:       [[LATCH]]:
+// CHECK:         cond_br undef, [[BACKEDGE:bb[0-9]+]], [[INFINITE_LOOP:bb[0-9]+]]
+// CHECK:       [[BACKEDGE]]:
+// CHECK:         dealloc_stack
+// CHECK:         br [[EXITING_LOOP]]
+// CHECK:       [[EXIT]]:
+// CHECK:         dealloc_stack
+// CHECK:       [[INFINITE_LOOP]]:
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'alloc_box_in_exiting_loop'
+sil @alloc_box_in_exiting_loop : $@convention(thin) () -> () {
+entry:
+  br exiting_loop
+
+exiting_loop:
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  cond_br undef, exit, latch
+
+latch:
+  cond_br undef, backedge, infinite_loop
+
+backedge:
+  strong_release %box
+  br exiting_loop
+
+exit:
+  strong_release %box
+  return undef : $()
+
+infinite_loop:
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c = apply %getC() : $@convention(thin) () -> (@owned C)
+  store %c to %c_addr
+  strong_retain %box
+  strong_release %box
+  br infinite_loop
+}
+
+// CHECK-LABEL: sil @alloc_box_in_deadend_loop_with_another_deadend
+// CHECK:         br [[LOOP:bb[0-9]+]]
+// CHECK:       [[LOOP]]:
+// CHECK:         alloc_stack
+// CHECK:         cond_br undef, [[BACKEDGE:bb[0-9]+]], [[DIE:bb[0-9]+]]
+// CHECK:       [[BACKEDGE]]:
+// CHECK:         dealloc_stack
+// CHECK:         br [[LOOP]]
+// CHECK:       [[DIE]]:
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'alloc_box_in_deadend_loop_with_another_deadend'
+sil @alloc_box_in_deadend_loop_with_another_deadend : $@convention(thin) () -> () {
+entry:
+  br loop
+
+loop:
+  %box = alloc_box ${ var C }
+  cond_br undef, backedge, die
+
+backedge:
+  strong_release %box
+  br loop
+
+die:
+  strong_retain %box
+  strong_release %box
+  unreachable
+}
diff --git a/test/SILOptimizer/allocbox_to_stack_noncopyable.sil b/test/SILOptimizer/allocbox_to_stack_noncopyable.sil
index 2e1621d8cd219..f92232e20ff3f 100644
--- a/test/SILOptimizer/allocbox_to_stack_noncopyable.sil
+++ b/test/SILOptimizer/allocbox_to_stack_noncopyable.sil
@@ -28,8 +28,7 @@ bb0(%0 : @closureCapture @guaranteed ${ var NonTrivialStruct }):
 // CHECK-NEXT:   [[STACK2:%.*]] = alloc_stack $NonTrivialStruct
 // CHECK-NEXT:   [[MARKED2:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[STACK2]]
 // CHECK-NEXT:   store [[LOADED_VALUE]] to [init] [[MARKED2]]
-// CHECK-NEXT:   // function_ref
-// CHECK-NEXT:   [[FUNC:%.*]] = function_ref @$s26host_markmustcheck_closureTf0s_n : $@convention(thin) (@inout_aliasable NonTrivialStruct) -> ()
+// CHECK:        [[FUNC:%.*]] = function_ref @$s26host_markmustcheck_closureTf0s_n : $@convention(thin) (@inout_aliasable NonTrivialStruct) -> ()
 // CHECK-NEXT:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[FUNC]]([[MARKED2]]) : $@convention(thin) (@inout_aliasable NonTrivialStruct) -> ()
 // CHECK-NEXT:   apply [[PA]]()
 // CHECK-NEXT:   destroy_value [[PA]]
diff --git a/test/SILOptimizer/allocbox_to_stack_ownership.sil b/test/SILOptimizer/allocbox_to_stack_ownership.sil
index a50f11903468b..06659d2f26ca9 100644
--- a/test/SILOptimizer/allocbox_to_stack_ownership.sil
+++ b/test/SILOptimizer/allocbox_to_stack_ownership.sil
@@ -1,4 +1,5 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -allocbox-to-stack -enable-copy-propagation=requested-passes-only | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types %s -allocbox-to-stack | %FileCheck %s --check-prefix=CHECK --check-prefix=OPT
+// RUN: %target-sil-opt -sil-print-types %s -mandatory-allocbox-to-stack | %FileCheck %s --check-prefix=CHECK --check-prefix=MANDATORY
 
 sil_stage raw
 
@@ -14,6 +15,8 @@ struct Bool {
 
 protocol Error {}
 
+class C {}
+
 // CHECK-LABEL: sil [ossa] @simple_promotion
 sil [ossa] @simple_promotion : $@convention(thin) (Int) -> Int {
 bb0(%0 : $Int):
@@ -123,10 +126,9 @@ bb1(%0 : $Int):
 
 sil [ossa] @callee : $@convention(thin) (@inout Int) -> ()
 
-// CHECK-LABEL: sil [ossa] @inout_nocapture
-sil [ossa] @inout_nocapture : $@convention(thin) () -> Int {
+// CHECK-LABEL: sil [ossa] @escaping_pointer
+sil [ossa] @escaping_pointer : $@convention(thin) () -> Int {
 bb0:
-  // CHECK: alloc_stack
   %1 = alloc_box ${ var Int }
   %1a = project_box %1 : ${ var Int }, 0
   %6 = function_ref @callee : $@convention(thin) (@inout Int) -> ()
@@ -394,8 +396,8 @@ bb0(%0 : $Int):
 }
 
 // CHECK-LABEL: sil private [transparent] [ossa] @$s6struct8useStack1tySi_tFSiycfU_Tf0s_n
-// CHECK-LABEL: sil private [transparent] [_semantics "sil.optimizer.delete_if_unused"] [ossa] @$s6struct8useStack1tySi_tFSiycfU_
-// struct.(useStack (t : Swift.Int) -> ()).(closure #1)
+// OPT-LABEL: sil private [transparent] [ossa] @$s6struct8useStack1tySi_tFSiycfU_ :
+// MANDATORY-NOT: sil private [transparent] [ossa] @$s6struct8useStack1tySi_tFSiycfU_ :
 sil private [transparent] [ossa] @$s6struct8useStack1tySi_tFSiycfU_ : $@convention(thin) (@owned <τ_0_0> { var τ_0_0 } <Int>) -> Int {
 bb0(%0 : @owned $<τ_0_0> { var τ_0_0 } <Int>):
   %1 = project_box %0 : $<τ_0_0> { var τ_0_0 } <Int>, 0
@@ -751,7 +753,8 @@ bb0(%0 : $Int, %1 : $*S<T>):
   return %9 : $Bool
 }
 
-// CHECK-LABEL: sil shared [_semantics "sil.optimizer.delete_if_unused"] [ossa] @closure1
+// OPT-LABEL:     sil shared [ossa] @closure1 :
+// MANDATORY-NOT: sil shared [ossa] @closure1 :
 sil shared [ossa] @closure1 : $@convention(thin) <T where T : Count> (Int, @owned <τ_0_0 : Count> { var S<τ_0_0> } <T>) -> Bool {
 // CHECK: bb0
 bb0(%0 : $Int, %1 : @owned $<τ_0_0 where τ_0_0 : Count> { var S<τ_0_0> } <T>):
@@ -773,9 +776,9 @@ bb0(%0 : $Int, %1 : @owned $<τ_0_0 where τ_0_0 : Count> { var S<τ_0_0> } <T>)
 // CHECK: return
 // CHECK-NOT: bb1
 
-// CHECK-LABEL: sil shared [_semantics "sil.optimizer.delete_if_unused"] [ossa] @closure2
+// OPT-LABEL: sil shared [ossa] @closure2 :
+// MANDATORY-NOT: sil shared [ossa] @closure2 :
 sil shared [ossa] @closure2 : $@convention(thin) <T where T : Count> (Int, @owned <τ_0_0 : Count> { var S<τ_0_0> } <T>) -> Bool {
-// CHECK: bb0
 bb0(%0 : $Int, %1 : @owned $<τ_0_0 where τ_0_0 : Count> { var S<τ_0_0> } <T>):
   %2 = project_box %1 : $<τ_0_0 where τ_0_0 : Count> { var S<τ_0_0> } <T>, 0
   %3 = function_ref @binary : $@convention(thin) (Int, Int) -> Bool
@@ -791,7 +794,6 @@ bb0(%0 : $Int, %1 : @owned $<τ_0_0 where τ_0_0 : Count> { var S<τ_0_0> } <T>)
   destroy_addr %4 : $*S<T>
   dealloc_stack %4 : $*S<T>
   destroy_value %1 : $<τ_0_0 where τ_0_0 : Count> { var S<τ_0_0> } <T>
-// CHECK: return
   return %8 : $Bool
 }
 
@@ -1006,7 +1008,6 @@ bb2:
 // CHECK:      bb1:
 // CHECK-NEXT:   [[STACK2:%[0-9]+]] = alloc_stack $Bool
 // CHECK-NEXT:   dealloc_stack [[STACK2]]
-// CHECK-NEXT:   dealloc_stack [[BOX]]
 // CHECK-NEXT:   unreachable
 // CHECK:      bb2:
 // CHECK:        store
@@ -1126,11 +1127,6 @@ bb2:
   return %r : $()
 }
 
-// Test that
-//  begin_access [read], copy_addr, end_access, destroy_addr
-// is folded into
-//  begin_access [deinit], copy_addr [take], end_access
-//
 // CHECK-LABEL: sil [ossa] @deinit_access : $@convention(thin) <T> (@in T) -> (@out T, @out T) {
 // CHECK: bb0(%0 : $*T, %1 : $*T, %2 : $*T):
 // CHECK: [[STK:%.*]] = alloc_stack $T, var, name "x"
@@ -1138,10 +1134,10 @@ bb2:
 // CHECK: [[READ:%.*]] = begin_access [read] [static] [[STK]] : $*T
 // CHECK: copy_addr [[READ]] to [init] %0 : $*T
 // CHECK: end_access [[READ]] : $*T
-// CHECK: [[READ:%.*]] = begin_access [deinit] [static] [[STK]] : $*T
-// CHECK: copy_addr [take] [[READ]] to [init] %1 : $*T
+// CHECK: [[READ:%.*]] = begin_access [read] [static] [[STK]] : $*T
+// CHECK: copy_addr [[READ]] to [init] %1 : $*T
 // CHECK: end_access [[READ]] : $*T
-// CHECK-NOT: destroy_addr
+// CHECK: destroy_addr [[STK]]
 // CHECK: dealloc_stack [[STK]] : $*T
 // CHECK: destroy_addr %2 : $*T
 // CHECK: return %{{.*}} : $()
@@ -1203,3 +1199,255 @@ bb0(%0 : $*T, %1 : $*T, %2 : $*T):
   %15 = tuple ()
   return %15 : $()
 }
+
+// CHECK-LABEL: sil [ossa] @alloc_box_in_specialized_callee :
+// CHECK-NOT:     alloc_box
+// CHECK-LABEL: } // end sil function 'alloc_box_in_specialized_callee'
+sil [ossa] @alloc_box_in_specialized_callee : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = alloc_box ${ var Int }
+  %2 = project_box %1, 0
+  store %0 to [trivial] %2
+  %4 = function_ref @callee_with_allocbox : $@convention(thin) (@guaranteed { var Int }) -> ()
+  %5 = apply %4(%1) : $@convention(thin) (@guaranteed { var Int }) -> ()
+  destroy_value %1
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s20callee_with_allocboxTf0s_n :
+// CHECK-NOT:     alloc_box
+// CHECK-LABEL: } // end sil function '$s20callee_with_allocboxTf0s_n'
+
+// CHECK-LABEL: sil [ossa] @callee_with_allocbox :
+// CHECK-NOT:     alloc_box
+// CHECK-LABEL: } // end sil function 'callee_with_allocbox'
+sil [ossa] @callee_with_allocbox : $@convention(thin) (@guaranteed { var Int }) -> () {
+bb0(%0 : @guaranteed ${ var Int }):
+  %1 = alloc_box ${ var Int }
+  %2 = project_box %1 : ${ var Int }, 0
+  %3 = project_box %0 : ${ var Int }, 0
+  copy_addr %3 to %2
+  destroy_value %1
+  %r = tuple ()
+  return %r
+}
+
+sil @getC : $@convention(thin) () -> (@owned C)
+
+// CHECK-LABEL: sil [ossa] @leak_to_inf_loop_1 : {{.*}} {
+// CHECK-NOT:     destroy_addr
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'leak_to_inf_loop_1'
+sil [ossa] @leak_to_inf_loop_1 : $@convention(thin) (@owned C) -> () {
+entry(%c : @owned $C):
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  store %c to [init] %c_addr
+  %copy = copy_value %box
+  destroy_value %box
+  br loop
+
+loop:
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c2 = apply %getC() : $@convention(thin) () -> (@owned C)
+  %c_old = load [take] %c_addr
+  store %c2 to [init] %c_addr
+  destroy_value %c_old
+  br loop
+}
+
+// CHECK-LABEL: sil [ossa] @leak_to_inf_loop_2 : {{.*}} {
+// CHECK:         cond_br undef, [[EXIT:bb[0-9]+]], [[TO_LOOP:bb[0-9]+]]
+// CHECK:       [[EXIT]]
+// CHECK:         destroy_addr
+// CHECK:         dealloc_stack
+// CHECK:       [[TO_LOOP]]
+// CHECK-NOT:     destroy_addr
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'leak_to_inf_loop_2'
+sil [ossa] @leak_to_inf_loop_2 : $@convention(thin) (@owned C) -> () {
+entry(%c : @owned $C):
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  store %c to [init] %c_addr
+  %copy = copy_value %box
+  destroy_value %box
+  cond_br undef, exit, to_loop
+
+exit:
+  destroy_value %copy
+  return undef : $()
+
+to_loop:
+  %copy2 = copy_value %copy
+  destroy_value %copy
+  br loop
+
+loop:
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c2 = apply %getC() : $@convention(thin) () -> (@owned C)
+  %c_old = load [take] %c_addr
+  store %c2 to [init] %c_addr
+  destroy_value %c_old
+  br loop
+}
+
+// CHECK-LABEL: sil [ossa] @leak_to_inf_loop_3 : {{.*}} {
+// CHECK-NOT:     destroy_addr
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'leak_to_inf_loop_3'
+sil [ossa] @leak_to_inf_loop_3 : $@convention(thin) (@owned C) -> () {
+entry(%c : @owned $C):
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  store %c to [init] %c_addr
+  br to_loop
+
+to_loop:
+  %copy = copy_value %box
+  destroy_value %box
+  br loop
+
+loop:
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c2 = apply %getC() : $@convention(thin) () -> (@owned C)
+  %c_old = load [take] %c_addr
+  store %c2 to [init] %c_addr
+  destroy_value %c_old
+  br loop
+}
+
+// CHECK-LABEL: sil [ossa] @dealloc_box_before_loop
+// CHECK:         dealloc_stack
+// CHECK-LABEL: } // end sil function 'dealloc_box_before_loop'
+sil [ossa] @dealloc_box_before_loop : $@convention(thin) (@owned C) -> () {
+entry(%c : @owned $C):
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  store %c to [init] %c_addr
+  cond_br undef, exit, to_loop
+
+exit:
+  destroy_value %box
+  return undef : $()
+
+to_loop:
+  dealloc_box %box
+  br loop
+
+loop:
+  br loop
+}
+
+// CHECK-LABEL: sil [ossa] @alloc_box_in_deadend_loop
+// CHECK:         alloc_stack
+// CHECK:         dealloc_stack
+// CHECK-LABEL: } // end sil function 'alloc_box_in_deadend_loop'
+sil [ossa] @alloc_box_in_deadend_loop : $@convention(thin) () -> () {
+entry:
+  br loop
+
+loop:
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c = apply %getC() : $@convention(thin) () -> (@owned C)
+  store %c to [init] %c_addr
+  destroy_value %box
+  br loop
+}
+
+// CHECK-LABEL: sil [ossa] @alloc_box_in_exiting_loop
+// CHECK:         br [[EXITING_LOOP:bb[0-9]+]]
+// CHECK:       [[EXITING_LOOP]]:
+// CHECK:         alloc_stack
+// CHECK:         cond_br undef, [[EXIT:bb[0-9]+]], [[LATCH:bb[0-9]+]]
+// CHECK:       [[LATCH]]:
+// CHECK:         cond_br undef, [[BACKEDGE:bb[0-9]+]], [[INFINITE_LOOP:bb[0-9]+]]
+// CHECK:       [[BACKEDGE]]:
+// CHECK:         dealloc_stack
+// CHECK:         br [[EXITING_LOOP]]
+// CHECK:       [[EXIT]]:
+// CHECK:         dealloc_stack
+// CHECK:       [[INFINITE_LOOP]]:
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'alloc_box_in_exiting_loop'
+sil [ossa] @alloc_box_in_exiting_loop : $@convention(thin) () -> () {
+entry:
+  br exiting_loop
+
+exiting_loop:
+  %box = alloc_box ${ var C }
+  %c_addr = project_box %box, 0
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %c = apply %getC() : $@convention(thin) () -> (@owned C)
+  store %c to [init] %c_addr
+  cond_br undef, exit, latch
+
+latch:
+  cond_br undef, backedge, to_infinite_loop
+
+backedge:
+  destroy_value %box
+  br exiting_loop
+
+exit:
+  destroy_value %box
+  return undef : $()
+
+to_infinite_loop:
+  br infinite_loop
+
+infinite_loop:
+  %c2 = apply %getC() : $@convention(thin) () -> (@owned C)
+  store %c2 to [assign] %c_addr
+  %copy = copy_value %box
+  destroy_value %copy
+  br infinite_loop
+}
+
+// CHECK-LABEL: sil [ossa] @alloc_box_in_deadend_loop_with_another_deadend
+// CHECK:         br [[LOOP:bb[0-9]+]]
+// CHECK:       [[LOOP]]:
+// CHECK:         alloc_stack
+// CHECK:         cond_br undef, [[BACKEDGE:bb[0-9]+]], [[DIE:bb[0-9]+]]
+// CHECK:       [[BACKEDGE]]:
+// CHECK:         dealloc_stack
+// CHECK:         br [[LOOP]]
+// CHECK:       [[DIE]]:
+// CHECK-NOT:     dealloc_stack
+// CHECK-LABEL: } // end sil function 'alloc_box_in_deadend_loop_with_another_deadend'
+sil [ossa] @alloc_box_in_deadend_loop_with_another_deadend : $@convention(thin) () -> () {
+entry:
+  br loop
+
+loop:
+  %box = alloc_box ${ var C }
+  cond_br undef, backedge, die
+
+backedge:
+  destroy_value %box
+  br loop
+
+die:
+  %copy = copy_value %box
+  destroy_value %copy
+  unreachable
+}
+
+// CHECK-LABEL: sil [ossa] @test_access_enforcement :
+// OPT:           begin_access [modify] [dynamic]
+// MANDATORY:     begin_access [modify] [static]
+// CHECK-LABEL: } // end sil function 'test_access_enforcement'
+sil [ossa] @test_access_enforcement : $(Int) -> Int {
+bb0(%0 : $Int):
+  %1 = alloc_box ${ var Int }
+  %2 = project_box %1 : ${ var Int }, 0
+  %3 = begin_access [modify] [dynamic] %2
+  store %0 to [trivial] %3
+  end_access %3
+  %4 = load [trivial] %2
+  destroy_value %1
+  return %4 : $Int
+}
diff --git a/test/SILOptimizer/allocboxtostack_escape.swift b/test/SILOptimizer/allocboxtostack_escape.swift
deleted file mode 100644
index 3dc44cfc259bc..0000000000000
--- a/test/SILOptimizer/allocboxtostack_escape.swift
+++ /dev/null
@@ -1,25 +0,0 @@
-// RUN: %target-swift-frontend %s -o /dev/null -verify -emit-sil
-
-struct Box<T> {
-  var value: T
-}
-
-class Klass {}
-
-func myPrint(_ x: inout Box<Klass>) -> () { print(x) }
-
-func testError() -> (() -> ()) {
-  // We emit this error twice since we run allocbox to stack twice in the pipeline for now. This is not an official feature, so it is ok for now.
-  @_semantics("boxtostack.mustbeonstack")
-  var x = Box<Klass>(value: Klass()) // expected-error {{Can not promote value from heap to stack due to value escaping}}
-  let result = { // expected-note {{value escapes here}}
-    myPrint(&x)
-  }
-  return result
-}
-
-func main() {
-  testError()()
-}
-
-main()
diff --git a/test/SILOptimizer/allocboxtostack_localapply.sil b/test/SILOptimizer/allocboxtostack_localapply.sil
index 1f926d2fe216c..462628094b7c3 100644
--- a/test/SILOptimizer/allocboxtostack_localapply.sil
+++ b/test/SILOptimizer/allocboxtostack_localapply.sil
@@ -257,7 +257,7 @@ bb0(%0 : ${ var Int64 }):
 }
 
 // CHECK-LABEL: sil [noinline] @$testrecur :
-// CHECK: alloc_box ${ var Int64 }, var, name "x"
+// CHECK:         alloc_stack $Int64, var, name "x"
 // CHECK-LABEL: } // end sil function '$testrecur'
 sil [noinline] @$testrecur : $@convention(thin) () -> () {
 bb0:
@@ -275,6 +275,7 @@ bb0:
   return %10 : $()
 }
 
+// CHECK-LABEL: sil private [noinline] @$s13$testrecurbarTf0s_n : $@convention(thin) (@inout_aliasable Int64) -> () {
 sil private [noinline] @$testrecurbar : $@convention(thin) (@guaranteed { var Int64 }) -> () {
 bb0(%0 : ${ var Int64 }):
   %1 = project_box %0 : ${ var Int64 }, 0
@@ -292,6 +293,7 @@ bb0(%0 : ${ var Int64 }):
   return %13 : $()
 }
 
+// CHECK-LABEL: sil private [noinline] @$s13$testrecurbasTf0s_n : $@convention(thin) (@inout_aliasable Int64) -> () {
 sil private [noinline] @$testrecurbas : $@convention(thin) (@guaranteed { var Int64 }) -> () {
 bb0(%0 : ${ var Int64 }):
   %1 = project_box %0 : ${ var Int64 }, 0
diff --git a/test/SILOptimizer/allocboxtostack_localapply.swift b/test/SILOptimizer/allocboxtostack_localapply.swift
index 51d99210f8f5c..188e7eef18afa 100644
--- a/test/SILOptimizer/allocboxtostack_localapply.swift
+++ b/test/SILOptimizer/allocboxtostack_localapply.swift
@@ -103,7 +103,7 @@ public func testboxescapes() -> (() -> ()) {
 }
 
 // CHECK-LABEL: sil [noinline] @$s26allocboxtostack_localapply9testrecurSiyF :
-// CHECK: alloc_box ${ var Int }, var, name "x"
+// CHECK:          alloc_stack [var_decl] $Int, var, name "x"
 // CHECK-LABEL: } // end sil function '$s26allocboxtostack_localapply9testrecurSiyF'
 @inline(never)
 public func testrecur() -> Int {
@@ -146,14 +146,9 @@ public func testdfs1() -> Int {
   return common()
 }
 
-// Test to make sure we don't optimize the case when we have an inner common function call for multiple boxes.
-// We don't optimize this case now, because we don't have additional logic to correctly construct AppliesToSpecialize
-// Order of function calls constructed in PromotedOperands: bar innercommon local1 bas innercommon local2
-// AppliesToSpecialize should have the order: bar bas innercommon local1 local2
-// Since we don't maintain any tree like data structure with more info on the call tree, this is not possible to construct today 
 // CHECK-LABEL: sil [noinline] @$s26allocboxtostack_localapply8testdfs2SiyF :
-// CHECK: alloc_box ${ var Int }, var, name "x"
-// CHECK: alloc_box ${ var Int }, var, name "y"
+// CHECK:          alloc_stack [var_decl] $Int, var, name "x"
+// CHECK:          alloc_stack [var_decl] $Int, var, name "y"
 // CHECK-LABEL:} // end sil function '$s26allocboxtostack_localapply8testdfs2SiyF'
 @inline(never)
 public func testdfs2() -> Int {
@@ -182,3 +177,24 @@ public func testdfs2() -> Int {
   return local1() + local2()
 }
 
+// CHECK-LABEL: sil @$s26allocboxtostack_localapply15call2localfuncsSiyF :
+// CHECK-NOT:     alloc_box
+// CHECK-NOT:     begin_access
+// CHECK-LABEL:} // end sil function '$s26allocboxtostack_localapply15call2localfuncsSiyF'
+public func call2localfuncs() -> Int {
+    var a1 = 1
+    
+    @inline(never)
+    func innerFunction() {
+        a1 += 1
+    }
+
+    innerFunction()
+    innerFunction()
+
+    return a1
+}
+
+// CHECK-LABEL: sil {{.*}} @$s26allocboxtostack_localapply15call2localfuncsSiyF13innerFunctionL_yyFTf0s_n :
+// CHECK-NOT:     begin_access
+// CHECK:       } // end sil function '$s26allocboxtostack_localapply15call2localfuncsSiyF13innerFunctionL_yyFTf0s_n'
diff --git a/test/SILOptimizer/allocboxtostack_localapply_ossa.sil b/test/SILOptimizer/allocboxtostack_localapply_ossa.sil
index 8f17660cae5a4..ebae46ef3d493 100644
--- a/test/SILOptimizer/allocboxtostack_localapply_ossa.sil
+++ b/test/SILOptimizer/allocboxtostack_localapply_ossa.sil
@@ -257,7 +257,7 @@ bb0(%0 : @guaranteed ${ var Int64 }):
 }
 
 // CHECK-LABEL: sil [noinline] [ossa] @$testrecur :
-// CHECK: alloc_box ${ var Int64 }, var, name "x"
+// CHECK:         alloc_stack $Int64, var, name "x"
 // CHECK-LABEL: } // end sil function '$testrecur'
 sil [noinline] [ossa] @$testrecur : $@convention(thin) () -> () {
 bb0:
@@ -409,15 +409,10 @@ bb0(%0 : @guaranteed ${ var Int64 }):
   return %4 : $Int64
 }
 
-// Test to make sure we don't optimize the case when we have an inner common function call for multiple boxes.
-// We don't optimize this case now, because we don't have additional logic to correctly construct AppliesToSpecialize
-// Order of function calls constructed in PromotedOperands: bar innercommon local1 bas innercommon local2
-// AppliesToSpecialize should have the order: bar bas innercommon local1 local2
-// Since we don't maintain any tree like data structure with more info on the call tree, this is not possible to construct today 
 // CHECK-LABEL: sil [noinline] [ossa] @$testdfs2 :
-// CHECK: alloc_box ${ var Int }, var, name "x"
-// CHECK: alloc_box ${ var Int }, var, name "y"
-// CHECK-LABEL:} // end sil function '$testdfs2'
+// CHECK:         alloc_stack $Int, var, name "x"
+// CHECK:         alloc_stack $Int, var, name "y"
+// CHECK-LABEL: } // end sil function '$testdfs2'
 sil [noinline] [ossa] @$testdfs2 : $@convention(thin) () -> Int {
 bb0:
   %0 = alloc_box ${ var Int }, var, name "x"
@@ -446,6 +441,7 @@ bb0:
   return %21 : $Int
 }
 
+// CHECK-LABEL: sil private [noinline] [ossa] @$s12$testdfs2barTf0s_n : $@convention(thin) (@inout_aliasable Int) -> Int {
 sil private [noinline] [ossa] @$testdfs2bar : $@convention(thin) (@guaranteed { var Int }) -> Int {
 bb0(%0 : @guaranteed ${ var Int }):
   %1 = project_box %0 : ${ var Int }, 0
@@ -453,6 +449,7 @@ bb0(%0 : @guaranteed ${ var Int }):
   return %4 : $Int
 }
 
+// CHECK-LABEL: sil private [noinline] [ossa] @$s12$testdfs2basTf0s_n : $@convention(thin) (@inout_aliasable Int) -> Int {
 sil private [noinline] [ossa] @$testdfs2bas : $@convention(thin) (@guaranteed { var Int }) -> Int {
 bb0(%0 : @guaranteed ${ var Int }):
   %1 = project_box %0 : ${ var Int }, 0
@@ -460,6 +457,7 @@ bb0(%0 : @guaranteed ${ var Int }):
   return %4 : $Int
 }
 
+// CHECK-LABEL: sil private [noinline] [ossa] @$s20$testdfs2innercommonTf0ss_n : $@convention(thin) (@inout_aliasable Int, @inout_aliasable Int) -> Int {
 sil private [noinline] [ossa] @$testdfs2innercommon : $@convention(thin) (@guaranteed { var Int }, @guaranteed { var Int }) -> Int {
 bb0(%0 : @guaranteed ${ var Int }, %1 : @guaranteed ${ var Int }):
   %2 = project_box %0 : ${ var Int }, 0
@@ -471,6 +469,7 @@ bb0(%0 : @guaranteed ${ var Int }, %1 : @guaranteed ${ var Int }):
   return %12 : $Int
 }
 
+// CHECK-LABEL: sil private [noinline] [ossa] @$s15$testdfs2local1Tf0ss_n : $@convention(thin) (@inout_aliasable Int, @inout_aliasable Int) -> Int {
 sil private [noinline] [ossa] @$testdfs2local1 : $@convention(thin) (@guaranteed { var Int }, @guaranteed { var Int }) -> Int {
 bb0(%0 : @guaranteed ${ var Int }, %1 : @guaranteed ${ var Int }):
   %2 = project_box %0 : ${ var Int }, 0
@@ -480,6 +479,7 @@ bb0(%0 : @guaranteed ${ var Int }, %1 : @guaranteed ${ var Int }):
   return %8 : $Int
 }
 
+// CHECK-LABEL: sil private [noinline] [ossa] @$s15$testdfs2local2Tf0ss_n : $@convention(thin) (@inout_aliasable Int, @inout_aliasable Int) -> Int {
 sil private [noinline] [ossa] @$testdfs2local2 : $@convention(thin) (@guaranteed { var Int }, @guaranteed { var Int }) -> Int {
 bb0(%0 : @guaranteed ${ var Int }, %1 : @guaranteed ${ var Int }):
   %2 = project_box %0 : ${ var Int }, 0
diff --git a/test/SILOptimizer/always_inline.sil b/test/SILOptimizer/always_inline.sil
index 9dcb6885d0772..ced6359c986fb 100644
--- a/test/SILOptimizer/always_inline.sil
+++ b/test/SILOptimizer/always_inline.sil
@@ -15,8 +15,8 @@ bb0:
   %4 = tuple ()
   return %4 : $()
 }
-// CHECK-LABEL: [always_inline] @noinline_callee
-sil [always_inline] @noinline_callee : $@convention(thin) (Builtin.Int64) -> Builtin.Int64 {
+// CHECK-LABEL: [heuristic_always_inline] @noinline_callee
+sil [heuristic_always_inline] @noinline_callee : $@convention(thin) (Builtin.Int64) -> Builtin.Int64 {
 bb0(%0 : $Builtin.Int64):
   %2 = integer_literal $Builtin.Int1, 0
   %3 = builtin "umul_with_overflow_Int64"(%0 : $Builtin.Int64, %0 : $Builtin.Int64, %2 : $Builtin.Int1) : $(Builtin.Int64, Builtin.Int1)
diff --git a/test/SILOptimizer/arcsequenceopts.sil b/test/SILOptimizer/arcsequenceopts.sil
index 8d591cb3455b4..bce10ea045995 100644
--- a/test/SILOptimizer/arcsequenceopts.sil
+++ b/test/SILOptimizer/arcsequenceopts.sil
@@ -2373,7 +2373,7 @@ sil_global hidden @$s4test12bufferMemorySpys5UInt8VGvp : $UnsafeMutablePointer<U
 // x
 sil_global hidden @$s4test1xypvp : $Any
 
-sil [serialized] [always_inline] [readonly] [_semantics "string.makeUTF8"] @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
+sil [serialized] [heuristic_always_inline] [readonly] [_semantics "string.makeUTF8"] @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
 
 // CHECK-LABEL: sil @testTsanInoutAccess : $@convention(thin) () -> () {
 // CHECK:   alloc_global @$s4test12bufferMemorySpys5UInt8VGvp
diff --git a/test/SILOptimizer/array_property_opt_ossa_guaranteed.sil b/test/SILOptimizer/array_property_opt_ossa_guaranteed.sil
index c7f406161fb90..3bbdc7519e7eb 100644
--- a/test/SILOptimizer/array_property_opt_ossa_guaranteed.sil
+++ b/test/SILOptimizer/array_property_opt_ossa_guaranteed.sil
@@ -76,6 +76,38 @@ bb3:
   return %4 : $MyBool
 }
 
+// Check that we don't crash with an ownership violation
+// CHECK-LABEL: sil [ossa] @borrow_use_in_dead_end : 
+// CHECK-LABEL: } // end sil function 'borrow_use_in_dead_end'
+sil [ossa] @borrow_use_in_dead_end : $@convention(thin) (@guaranteed MyArray<MyClass>) -> () {
+bb0(%0 : @guaranteed $MyArray<MyClass>):
+  br bb1
+
+bb1:
+  %2 = function_ref @arrayPropertyIsNative : $@convention(method) (@guaranteed MyArray<MyClass>) -> Bool
+  %5 = apply %2(%0) : $@convention(method) (@guaranteed MyArray<MyClass>) -> Bool
+  %10 = alloc_ref $MyClass
+  %11 = begin_borrow %10
+  cond_br undef, bb2, bb3
+
+bb2:
+  fix_lifetime %11
+  unreachable
+
+bb3:
+  end_borrow %11
+  destroy_value %10
+  cond_br undef, bb4, bb5
+
+bb4:
+  br bb1
+
+bb5:
+  %r = tuple ()
+  return %r
+}
+
+
 // CHECK-LABEL: sil [ossa] @load_and_copy_within_loop : 
 // CHECK: bb1:
 // CHECK: [[FUNC1:%.*]] = function_ref @arrayPropertyIsNative
diff --git a/test/SILOptimizer/assemblyvision_remark/all.swift b/test/SILOptimizer/assemblyvision_remark/all.swift
new file mode 100644
index 0000000000000..6e48dbbcfdcf0
--- /dev/null
+++ b/test/SILOptimizer/assemblyvision_remark/all.swift
@@ -0,0 +1,27 @@
+// RUN: %target-swift-frontend -enable-assembly-vision-all -emit-sil %s -Osize -o - -module-name main 2>&1 | %FileCheck %s
+// RUN: %target-swift-frontend -enable-assembly-vision-all -emit-sil %s -Osize -o - -module-name main 2>&1 | %FileCheck %s --check-prefix=REMARK
+
+public class C {
+
+  // CHECK: sil [transparent] [_semantics "optremark"] @$s4main1CC1iSivg
+  public var i: Int = 0
+
+  // CHECK: sil hidden [_semantics "optremark"] @$s4main1CCACycfc
+  init() {
+      print("\(i)")
+  }
+
+  // CHECK: sil [_semantics "optremark"] @$s4main1CC6methodSiyF
+  public func method() -> Int {
+// REMARK: 17:14: remark: begin exclusive access to value of type 'Int'
+      return i
+// REMARK: 17:14: remark: end exclusive access to value of type 'Int'
+  }
+
+  // CHECK: sil [_semantics "optremark"] @$s4main1CCfd
+}
+
+// CHECK sil [_semantics "optremark"] @$s4main12freestandingAA1CCyF
+public func freestanding() -> C {
+    return C()
+}
diff --git a/test/SILOptimizer/assemblyvision_remark/basic_yaml.swift b/test/SILOptimizer/assemblyvision_remark/basic_yaml.swift
index 8711c75986f1b..875691cf05371 100644
--- a/test/SILOptimizer/assemblyvision_remark/basic_yaml.swift
+++ b/test/SILOptimizer/assemblyvision_remark/basic_yaml.swift
@@ -1,7 +1,7 @@
 // RUN: %target-swiftc_driver -O -Rpass-missed=sil-assembly-vision-remark-gen -Xllvm -sil-disable-pass=FunctionSignatureOpts -Xfrontend -enable-copy-propagation -emit-sil %s -o /dev/null -Xfrontend -verify
 
 // RUN: %empty-directory(%t)
-// RUN: %target-swiftc_driver -wmo -O -Xllvm -sil-disable-pass=FunctionSignatureOpts -Xfrontend -enable-copy-propagation -emit-sil -save-optimization-record=yaml  -save-optimization-record-path %t/note.yaml %s -o /dev/null && %FileCheck --input-file=%t/note.yaml %s
+// RUN: %target-swiftc_driver -wmo -O -Xllvm -sil-disable-pass=FunctionSignatureOpts -Xfrontend -enable-copy-propagation -emit-sil -save-optimization-record=yaml -save-optimization-record-path %t/note.yaml -module-name optrecordmod %s -o /dev/null && %FileCheck --input-file=%t/note.yaml %s
 
 // REQUIRES: optimized_stdlib,swift_stdlib_no_asserts
 // REQUIRES: swift_in_compiler
@@ -30,7 +30,7 @@ public var global = Klass() // expected-remark {{heap allocated ref of type 'Kla
 // CHECK-NEXT: Name:            sil.memory
 // CHECK-NEXT: DebugLoc:        { File: '{{.*}}basic_yaml.swift', 
 // CHECK-NEXT:                    Line: [[# @LINE + 42 ]], Column: 12 }
-// CHECK-NEXT: Function:        'getGlobal()'
+// CHECK-NEXT: Function:        '$s12optrecordmod9getGlobalAA5KlassCyF'
 // CHECK-NEXT: Args:
 // CHECK-NEXT:   - String:          'begin exclusive access to value of type '''
 // CHECK-NEXT:   - ValueType:       Klass
@@ -45,7 +45,7 @@ public var global = Klass() // expected-remark {{heap allocated ref of type 'Kla
 // CHECK-NEXT: Name:            sil.memory
 // CHECK-NEXT: DebugLoc:        { File: '{{.*}}basic_yaml.swift', 
 // CHECK-NEXT:                    Line: [[# @LINE + 27 ]], Column: 12 }
-// CHECK-NEXT: Function:        'getGlobal()'
+// CHECK-NEXT: Function:        '$s12optrecordmod9getGlobalAA5KlassCyF'
 // CHECK-NEXT: Args:
 // CHECK-NEXT:   - String:          'end exclusive access to value of type '''
 // CHECK-NEXT:   - ValueType:       Klass
@@ -60,7 +60,7 @@ public var global = Klass() // expected-remark {{heap allocated ref of type 'Kla
 // CHECK-NEXT: Name:            sil.memory
 // CHECK-NEXT: DebugLoc:        { File: '{{.*}}basic_yaml.swift',
 // CHECK-NEXT:                    Line: [[# @LINE + 12]], Column: 5 }
-// CHECK-NEXT: Function:        'getGlobal()'
+// CHECK-NEXT: Function:        '$s12optrecordmod9getGlobalAA5KlassCyF'
 // CHECK-NEXT: Args:
 // CHECK-NEXT:   - String:          'retain of type '''
 // CHECK-NEXT:   - ValueType:       Klass
@@ -85,7 +85,7 @@ public func getGlobal() -> Klass {
 // CHECK-NEXT: Name:            sil.memory
 // CHECK-NEXT: DebugLoc:        { File: '{{.*}}basic_yaml.swift', 
 // CHECK-NEXT:                    Line: [[# @LINE + 51 ]], Column: 11 }
-// CHECK-NEXT: Function:        'useGlobal()'
+// CHECK-NEXT: Function:        '$s12optrecordmod9useGlobalyyF'
 // CHECK-NEXT: Args:
 // CHECK-NEXT:   - String:          'heap allocated ref of type '''
 // CHECK-NEXT:   - ValueType:
@@ -96,7 +96,7 @@ public func getGlobal() -> Klass {
 // CHECK-NEXT: Name:            sil.memory
 // CHECK-NEXT: DebugLoc:        { File: '{{.*}}basic_yaml.swift', 
 // CHECK-NEXT:                    Line: [[# @LINE + 40 ]], Column: 5 }
-// CHECK-NEXT: Function:        'useGlobal()'
+// CHECK-NEXT: Function:        '$s12optrecordmod9useGlobalyyF'
 // CHECK-NEXT: Args:
 // CHECK-NEXT:   - String:          'retain of type '''
 // CHECK-NEXT:   - ValueType:       Klass
@@ -110,7 +110,7 @@ public func getGlobal() -> Klass {
 // CHECK-NEXT: Name:            sil.memory
 // CHECK-NEXT: DebugLoc:        { File: '{{.*}}basic_yaml.swift', 
 // CHECK-NEXT:                    Line: [[# @LINE + 26 ]], Column: 12 }
-// CHECK-NEXT: Function:        'useGlobal()'
+// CHECK-NEXT: Function:        '$s12optrecordmod9useGlobalyyF'
 // CHECK-NEXT: Args:
 // CHECK-NEXT:   - String:          'release of type '''
 // CHECK-NEXT:   - ValueType:
@@ -121,7 +121,7 @@ public func getGlobal() -> Klass {
 // CHECK-NEXT: Name:            sil.memory
 // CHECK-NEXT: DebugLoc:        { File: '{{.*}}basic_yaml.swift', 
 // CHECK-NEXT:                    Line: [[# @LINE + 15 ]], Column: 12 }
-// CHECK-NEXT: Function:        'useGlobal()'
+// CHECK-NEXT: Function:        '$s12optrecordmod9useGlobalyyF'
 // CHECK-NEXT: Args:
 // CHECK-NEXT:   - String:          'release of type '''
 // CHECK-NEXT:   - ValueType:       Klass
diff --git a/test/SILOptimizer/assemblyvision_remark/cast_remarks.swift b/test/SILOptimizer/assemblyvision_remark/cast_remarks.swift
index 16076b3225acf..6311a5d57d82c 100644
--- a/test/SILOptimizer/assemblyvision_remark/cast_remarks.swift
+++ b/test/SILOptimizer/assemblyvision_remark/cast_remarks.swift
@@ -2,6 +2,7 @@
 
 // REQUIRES: optimized_stdlib
 // REQUIRES: swift_stdlib_no_asserts
+// REQUIRES: OS=macosx
 
 ///////////////////
 // Generic Casts //
diff --git a/test/SILOptimizer/basic-aa.sil b/test/SILOptimizer/basic-aa.sil
index 497f0085411fb..c34ca6eb7c401 100644
--- a/test/SILOptimizer/basic-aa.sil
+++ b/test/SILOptimizer/basic-aa.sil
@@ -665,6 +665,25 @@ bb0:
   %99 = tuple ()
   return %99 : $()
 }
+
+class Derived: X {}
+ 
+// CHECK-LABEL: @test_tail_addr_and_upcast
+// CHECK:       PAIR #10.
+// CHECK-NEXT:    %2 = ref_tail_addr %1 : $X, $Int32
+// CHECK-NEXT:    %3 = ref_tail_addr %0 : $Derived, $Int32
+// CHECK-NEXT:  MayAlias
+sil @test_tail_addr_and_upcast : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_ref $Derived
+  %1 = upcast %0 to $X
+  %2 = ref_tail_addr %1, $Int32
+  %3 = ref_tail_addr %0, $Int32
+  fix_lifetime %2
+  fix_lifetime %3
+  %r = tuple ()
+  return %r
+}
  
 class GenericClass<T> {
   var x : T
diff --git a/test/SILOptimizer/basic-callee-printer.sil b/test/SILOptimizer/basic-callee-printer.sil
index 096fbc2ba54b6..098b5b65547ce 100644
--- a/test/SILOptimizer/basic-callee-printer.sil
+++ b/test/SILOptimizer/basic-callee-printer.sil
@@ -702,7 +702,7 @@ sil_witness_table hidden SingleConformance: PublicProtocol module nix {
 
 sil @closureIntArg : $@convention(thin) (InitVal) -> ()
 
-// CHECK-LABEL-LABEL: Function call site:
+// CHECK-LABEL: Function call site:
 // CHECK: convert_escape_to_noescape
 // CHECK: apply %{{.*}}() : $@noescape @callee_guaranteed () -> ()
 // CHECK: Incomplete callee list? : No
diff --git a/test/SILOptimizer/borrowed_from_updater.sil b/test/SILOptimizer/borrowed_from_updater.sil
index df4cf019f1450..d54073e383dbf 100644
--- a/test/SILOptimizer/borrowed_from_updater.sil
+++ b/test/SILOptimizer/borrowed_from_updater.sil
@@ -300,3 +300,47 @@ bb2(%5 : @guaranteed $C):
   return %0 : $C
 }
 
+class Klass {}
+
+public struct Wrapper {
+  @_hasStorage var _k: Klass { get set }
+  var k: Klass
+}
+
+public struct GenWrapper<T> {
+  @_hasStorage var _prop: T { get set }
+  public var prop: T
+}
+
+// CHECK-LABEL: sil [ossa] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+sil [ossa] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+bb0(%0 : @guaranteed $Wrapper):
+  %2 = struct_extract %0, #Wrapper._k
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @test_borrow_accessor :
+// CHECK: bb3([[PHI:%.*]] : @guaranteed $Klass):
+// CHECK: [[B:%.*]] = borrowed [[PHI]] : $Klass from (%1 : $Wrapper)
+// CHECK-LABEL: } // end sil function 'test_borrow_accessor'
+sil [ossa] @test_borrow_accessor : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  %1 = begin_borrow %0
+  %2 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  cond_br undef, bb1, bb2
+
+bb1:
+  %3 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  br bb3(%3)
+
+bb2:
+  %5 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  br bb3(%5)
+
+bb3(%7 : @guaranteed $Klass):
+  end_borrow %1
+  destroy_value %0
+  %t = tuple ()
+  return %t
+}
+
diff --git a/test/SILOptimizer/canonicalize_borrow_scope_unit.sil b/test/SILOptimizer/canonicalize_borrow_scope_unit.sil
index a4dfb1d05acfd..6aaf85b8120bb 100644
--- a/test/SILOptimizer/canonicalize_borrow_scope_unit.sil
+++ b/test/SILOptimizer/canonicalize_borrow_scope_unit.sil
@@ -19,17 +19,17 @@ struct Unmanaged<Instance> where Instance : AnyObject {
   unowned(unsafe) var _value: @sil_unmanaged Instance
 }
 
-// CHECK-LABEL: begin {{.*}} on copy_and_move_argument: canonicalize_borrow_scope
+// CHECK-LABEL: begin {{.*}} on copy_and_move_argument: ossa_canonicalize_guaranteed
 // CHECK-LABEL: sil [ossa] @copy_and_move_argument : {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[INSTANCE:%[^,]+]] :
 // CHECK:         [[UNMANAGED:%[^,]+]] = ref_to_unmanaged [[INSTANCE]]
 // CHECK:         [[RETVAL:%[^,]+]] = struct $Unmanaged<Instance> ([[UNMANAGED]] : $@sil_unmanaged Instance) 
 // CHECK:         return [[RETVAL]]
 // CHECK-LABEL: } // end sil function 'copy_and_move_argument'
-// CHECK-LABEL: end {{.*}} on copy_and_move_argument: canonicalize_borrow_scope
+// CHECK-LABEL: end {{.*}} on copy_and_move_argument: ossa_canonicalize_guaranteed
 sil [ossa] @copy_and_move_argument : $@convention(thin) <Instance where Instance : AnyObject> (@guaranteed Instance) -> Unmanaged<Instance> {
 bb0(%instance : @guaranteed $Instance):
-  specify_test "canonicalize_borrow_scope @argument"
+  specify_test "ossa_canonicalize_guaranteed @argument"
   %copy_1 = copy_value %instance : $Instance
   %copy_2 = copy_value %copy_1 : $Instance
   %move = move_value %copy_2 : $Instance
@@ -44,17 +44,17 @@ bb0(%instance : @guaranteed $Instance):
   return %retval : $Unmanaged<Instance>
 }
 
-// CHECK-LABEL: begin {{.*}} on copy_and_move_lexical_argument: canonicalize_borrow_scope
+// CHECK-LABEL: begin {{.*}} on copy_and_move_lexical_argument: ossa_canonicalize_guaranteed
 // CHECK-LABEL: sil [ossa] @copy_and_move_lexical_argument : {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[INSTANCE:%[^,]+]] :
 // CHECK:         [[UNMANAGED:%[^,]+]] = ref_to_unmanaged [[INSTANCE]]
 // CHECK:         [[RETVAL:%[^,]+]] = struct $Unmanaged<Instance> ([[UNMANAGED]] : $@sil_unmanaged Instance) 
 // CHECK:         return [[RETVAL]]
 // CHECK-LABEL: } // end sil function 'copy_and_move_lexical_argument'
-// CHECK-LABEL: end {{.*}} on copy_and_move_lexical_argument: canonicalize_borrow_scope
+// CHECK-LABEL: end {{.*}} on copy_and_move_lexical_argument: ossa_canonicalize_guaranteed
 sil [ossa] @copy_and_move_lexical_argument : $@convention(thin) <Instance where Instance : AnyObject> (@guaranteed Instance) -> Unmanaged<Instance> {
 bb0(%instance : @guaranteed $Instance):
-  specify_test "canonicalize_borrow_scope @argument"
+  specify_test "ossa_canonicalize_guaranteed @argument"
   %copy_1 = copy_value %instance : $Instance
   %copy_2 = copy_value %copy_1 : $Instance
   %move = move_value [lexical] %copy_2 : $Instance
@@ -69,7 +69,7 @@ bb0(%instance : @guaranteed $Instance):
   return %retval : $Unmanaged<Instance>
 }
 
-// CHECK-LABEL: begin running test {{.*}} on dont_rewrite_inner_forwarding_user: canonicalize_borrow_scope
+// CHECK-LABEL: begin running test {{.*}} on dont_rewrite_inner_forwarding_user: ossa_canonicalize_guaranteed
 // CHECK-LABEL: sil [ossa] @dont_rewrite_inner_forwarding_user : {{.*}} {
 // CHECK:         [[GET_C:%[^,]+]] = function_ref @getD
 // CHECK:         [[TAKE_C:%[^,]+]] = function_ref @takeC
@@ -84,12 +84,12 @@ bb0(%instance : @guaranteed $Instance):
 // CHECK:         destroy_value [[C]]
 // CHECK:         return [[OUTER_UPCAST]]
 // CHECK-LABEL: } // end sil function 'dont_rewrite_inner_forwarding_user'
-// CHECK-LABEL: end running test {{.*}} on dont_rewrite_inner_forwarding_user: canonicalize_borrow_scope
+// CHECK-LABEL: end running test {{.*}} on dont_rewrite_inner_forwarding_user: ossa_canonicalize_guaranteed
 sil [ossa] @dont_rewrite_inner_forwarding_user : $@convention(thin) () -> (@owned C) {
     %getD = function_ref @getD : $@convention(thin) () -> (@owned D)
     %takeC = function_ref @takeC : $@convention(thin) (@owned C) -> ()
     %d = apply %getD() : $@convention(thin) () -> (@owned D)
-    specify_test "canonicalize_borrow_scope @instruction"
+    specify_test "ossa_canonicalize_guaranteed @instruction"
     %b = begin_borrow %d : $D
     %c2 = copy_value %b : $D
     %u2 = upcast %c2 : $D to $C
@@ -101,7 +101,7 @@ sil [ossa] @dont_rewrite_inner_forwarding_user : $@convention(thin) () -> (@owne
     return %u2 : $C
 }
 
-// CHECK-LABEL: begin running test {{.*}} on dont_hoist_inner_destructure: canonicalize_borrow_scope
+// CHECK-LABEL: begin running test {{.*}} on dont_hoist_inner_destructure: ossa_canonicalize_guaranteed
 // CHECK-LABEL: sil [ossa] @dont_hoist_inner_destructure : {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[S:%[^,]+]] :
 // CHECK:         [[OUTER_COPY:%[^,]+]] = copy_value [[S]]
@@ -123,10 +123,10 @@ sil [ossa] @dont_rewrite_inner_forwarding_user : $@convention(thin) () -> (@owne
 // CHECK:         br [[EXIT]]                                          
 // CHECK:       [[EXIT]]:                                              
 // CHECK-LABEL: } // end sil function 'dont_hoist_inner_destructure'
-// CHECK-LABEL: end running test {{.*}} on dont_hoist_inner_destructure: canonicalize_borrow_scope
+// CHECK-LABEL: end running test {{.*}} on dont_hoist_inner_destructure: ossa_canonicalize_guaranteed
 sil [ossa] @dont_hoist_inner_destructure : $@convention(thin) (@owned S) -> () {
 entry(%s : @owned $S):
-  specify_test "canonicalize_borrow_scope @instruction"
+  specify_test "ossa_canonicalize_guaranteed @instruction"
   %s_borrow = begin_borrow %s : $S
   %s_copy = copy_value %s_borrow : $S
   cond_br undef, left, right
diff --git a/test/SILOptimizer/canonicalize_ossa_lifetime_unit.sil b/test/SILOptimizer/canonicalize_ossa_lifetime_unit.sil
index 9d61203ca1bbd..21cf083411929 100644
--- a/test/SILOptimizer/canonicalize_ossa_lifetime_unit.sil
+++ b/test/SILOptimizer/canonicalize_ossa_lifetime_unit.sil
@@ -27,11 +27,11 @@ struct S {}
 struct MoS: ~Copyable {}
 struct MoE: ~Copyable {}
 
-// CHECK-LABEL: begin running test 1 of 1 on fn: canonicalize_ossa_lifetime with: true, true, true, @trace
-// CHECK-LABEL: end running test 1 of 1 on fn: canonicalize_ossa_lifetime with: true, true, true, @trace
+// CHECK-LABEL: begin running test 1 of 1 on fn: ossa_canonicalize_lifetime with: true, true, true, @trace
+// CHECK-LABEL: end running test 1 of 1 on fn: ossa_canonicalize_lifetime with: true, true, true, @trace
 sil [ossa] @fn : $@convention(thin) () -> () {
 entry:
-    specify_test "canonicalize_ossa_lifetime true true true @trace"
+    specify_test "ossa_canonicalize_lifetime true true true @trace"
     %getC = function_ref @getC : $@convention(thin) () -> @owned C
     %c = apply %getC() : $@convention(thin) () -> @owned C
     debug_value [trace] %c : $C
@@ -45,7 +45,7 @@ entry:
 
 // When access scopes are respected, the lifetime which previously extended
 // beyond the access scope still extends beyond it.
-// CHECK-LABEL: begin running test 1 of 2 on retract_value_lifetime_into_access_scope_when_access_scopes_not_respected: canonicalize_ossa_lifetime with: true, false, true, @trace
+// CHECK-LABEL: begin running test 1 of 2 on retract_value_lifetime_into_access_scope_when_access_scopes_not_respected: ossa_canonicalize_lifetime with: true, false, true, @trace
 // CHECK-LABEL: sil [ossa] @retract_value_lifetime_into_access_scope_when_access_scopes_not_respected {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[ADDR:%[^,]+]] :
 // CHECK:         [[INSTANCE:%[^,]+]] = apply
@@ -55,11 +55,11 @@ entry:
 // CHECK:         end_access [[ACCESS]]
 // CHECK:         destroy_value [[INSTANCE]]
 // CHECK-LABEL: } // end sil function 'retract_value_lifetime_into_access_scope_when_access_scopes_not_respected'
-// CHECK-LABEL: end running test 1 of 2 on retract_value_lifetime_into_access_scope_when_access_scopes_not_respected: canonicalize_ossa_lifetime with: true, false, true, @trace
+// CHECK-LABEL: end running test 1 of 2 on retract_value_lifetime_into_access_scope_when_access_scopes_not_respected: ossa_canonicalize_lifetime with: true, false, true, @trace
 
 // When access scopes are not respected, the lifetime which previously extended
 // beyond the access scope is retracted into the scope.
-// CHECK-LABEL: begin running test 2 of 2 on retract_value_lifetime_into_access_scope_when_access_scopes_not_respected: canonicalize_ossa_lifetime with: true, false, false, @trace
+// CHECK-LABEL: begin running test 2 of 2 on retract_value_lifetime_into_access_scope_when_access_scopes_not_respected: ossa_canonicalize_lifetime with: true, false, false, @trace
 // CHECK-LABEL: sil [ossa] @retract_value_lifetime_into_access_scope_when_access_scopes_not_respected {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[ADDR:%[^,]+]] :
 // CHECK:         [[INSTANCE:%[^,]+]] = apply
@@ -67,15 +67,15 @@ entry:
 // CHECK:         store [[INSTANCE]] to [init] [[ACCESS]]
 // CHECK:         end_access [[ACCESS]]
 // CHECK-LABEL: } // end sil function 'retract_value_lifetime_into_access_scope_when_access_scopes_not_respected'
-// CHECK-LABEL: end running test 2 of 2 on retract_value_lifetime_into_access_scope_when_access_scopes_not_respected: canonicalize_ossa_lifetime with: true, false, false, @trace
+// CHECK-LABEL: end running test 2 of 2 on retract_value_lifetime_into_access_scope_when_access_scopes_not_respected: ossa_canonicalize_lifetime with: true, false, false, @trace
 sil [ossa] @retract_value_lifetime_into_access_scope_when_access_scopes_not_respected : $@convention(thin) () -> @out C {
 bb0(%addr : $*C):
   %instance = apply undef() : $@convention(thin) () -> @owned C
   debug_value [trace] %instance : $C
                                                    // respect access scopes
                                                    // VVVV
-  specify_test "canonicalize_ossa_lifetime true false true @trace"
-  specify_test "canonicalize_ossa_lifetime true false false @trace"
+  specify_test "ossa_canonicalize_lifetime true false true @trace"
+  specify_test "ossa_canonicalize_lifetime true false false @trace"
                                                    // ^^^^^
                                                    // respect access scopes
   %copy = copy_value %instance : $C
@@ -88,17 +88,17 @@ bb0(%addr : $*C):
 }
 
 
-// CHECK-LABEL: begin running test 1 of 1 on reuse_destroy_after_barrier_phi: canonicalize_ossa_lifetime with: true, false, true, @trace
+// CHECK-LABEL: begin running test 1 of 1 on reuse_destroy_after_barrier_phi: ossa_canonicalize_lifetime with: true, false, true, @trace
 // CHECK-LABEL: sil [ossa] @reuse_destroy_after_barrier_phi : {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[INSTANCE:%[^,]+]] :
 // CHECK:       {{bb[0-9]+}}({{%[^,]+}}
 // CHECK:         destroy_value [[INSTANCE]]
 // CHECK-LABEL: } // end sil function 'reuse_destroy_after_barrier_phi'
-// CHECK-LABEL: end running test 1 of 1 on reuse_destroy_after_barrier_phi: canonicalize_ossa_lifetime with: true, false, true, @trace
+// CHECK-LABEL: end running test 1 of 1 on reuse_destroy_after_barrier_phi: ossa_canonicalize_lifetime with: true, false, true, @trace
 sil [ossa] @reuse_destroy_after_barrier_phi : $@convention(thin) (@owned C) -> @owned C {
 entry(%instance : @owned $C):
   debug_value [trace] %instance : $C
-  specify_test "canonicalize_ossa_lifetime true false true @trace"
+  specify_test "ossa_canonicalize_lifetime true false true @trace"
   %get = function_ref @getOwned : $@convention(thin) () -> @owned C
   cond_br undef, through, loop
 
@@ -115,16 +115,16 @@ exit(%out : @owned $C):
   return %out : $C
 }
 
-// CHECK-LABEL: begin running test 1 of 1 on store_arg_to_out_addr: canonicalize_ossa_lifetime with: true, false, true, @trace
+// CHECK-LABEL: begin running test 1 of 1 on store_arg_to_out_addr: ossa_canonicalize_lifetime with: true, false, true, @trace
 // CHECK-LABEL: sil [ossa] @store_arg_to_out_addr : $@convention(thin) (@owned C) -> @out C {
 // CHECK:       {{bb[0-9]+}}([[ADDR:%[^,]+]] : $*C, [[INSTANCE:%[^,]+]] :
 // CHECK:       store [[INSTANCE]] to [init] [[ADDR]]
 // CHECK-LABEL: } // end sil function 'store_arg_to_out_addr'
-// CHECK-LABEL: end running test 1 of 1 on store_arg_to_out_addr: canonicalize_ossa_lifetime with: true, false, true, @trace
+// CHECK-LABEL: end running test 1 of 1 on store_arg_to_out_addr: ossa_canonicalize_lifetime with: true, false, true, @trace
 sil [ossa] @store_arg_to_out_addr : $@convention(thin) (@owned C) -> @out C {
 bb0(%0 : $*C, %instance : @owned $C):
   debug_value [trace] %instance : $C
-  specify_test "canonicalize_ossa_lifetime true false true @trace"
+  specify_test "ossa_canonicalize_lifetime true false true @trace"
   %copy = copy_value %instance : $C
   store %copy to [init] %0 : $*C
   destroy_value %instance : $C
@@ -132,7 +132,7 @@ bb0(%0 : $*C, %instance : @owned $C):
   return %retval : $()
 }
 
-// CHECK-LABEL: begin running test 1 of 1 on store_arg_to_out_addr_with_barrier: canonicalize_ossa_lifetime with: true, false, true, @trace
+// CHECK-LABEL: begin running test 1 of 1 on store_arg_to_out_addr_with_barrier: ossa_canonicalize_lifetime with: true, false, true, @trace
 // CHECK-LABEL: sil [ossa] @store_arg_to_out_addr_with_barrier : $@convention(thin) (@owned C) -> @out C {
 // CHECK:       {{bb[0-9]+}}([[ADDR:%[^,]+]] : $*C, [[INSTANCE:%[^,]+]] :
 // CHECK:         [[BARRIER:%[^,]+]] = function_ref @barrier
@@ -141,12 +141,12 @@ bb0(%0 : $*C, %instance : @owned $C):
 // CHECK:         apply [[BARRIER]]()
 // CHECK:         destroy_value [[INSTANCE]]
 // CHECK-LABEL: } // end sil function 'store_arg_to_out_addr_with_barrier'
-// CHECK-LABEL: end running test 1 of 1 on store_arg_to_out_addr_with_barrier: canonicalize_ossa_lifetime with: true, false, true, @trace
+// CHECK-LABEL: end running test 1 of 1 on store_arg_to_out_addr_with_barrier: ossa_canonicalize_lifetime with: true, false, true, @trace
 sil [ossa] @store_arg_to_out_addr_with_barrier : $@convention(thin) (@owned C) -> @out C {
 bb0(%0 : $*C, %instance : @owned $C):
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   debug_value [trace] %instance : $C
-  specify_test "canonicalize_ossa_lifetime true false true @trace"
+  specify_test "ossa_canonicalize_lifetime true false true @trace"
   %copy = copy_value %instance : $C
   store %copy to [init] %0 : $*C
   apply %barrier() : $@convention(thin) () -> ()
@@ -167,7 +167,7 @@ right2(%c2p : @owned $C):
 
 exit(%phi : @owned $C, %typhi : $S):
   debug_value [trace] %phi : $C
-  specify_test "canonicalize_ossa_lifetime true false true @trace"
+  specify_test "ossa_canonicalize_lifetime true false true @trace"
   destroy_value %phi : $C
   %retval = tuple ()
   return %retval : $()
@@ -182,16 +182,16 @@ bb0:
 
 // Even though the apply of %empty is not a deinit barrier, verify that the
 // destroy is not hoisted, because MoS is move-only.
-// CHECK-LABEL: begin running test {{.*}} on dont_move_destroy_value_of_moveonly_struct: canonicalize_ossa_lifetime with: true, false, true, @argument
+// CHECK-LABEL: begin running test {{.*}} on dont_move_destroy_value_of_moveonly_struct: ossa_canonicalize_lifetime with: true, false, true, @argument
 // CHECK-LABEL: sil [ossa] @dont_move_destroy_value_of_moveonly_struct : {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[INSTANCE:%[^,]+]] :
 // CHECK:         apply
 // CHECK:         destroy_value [[INSTANCE]]
 // CHECK-LABEL: } // end sil function 'dont_move_destroy_value_of_moveonly_struct'
-// CHECK-LABEL: end running test {{.*}} on dont_move_destroy_value_of_moveonly_struct: canonicalize_ossa_lifetime with: true, false, true, @argument
+// CHECK-LABEL: end running test {{.*}} on dont_move_destroy_value_of_moveonly_struct: ossa_canonicalize_lifetime with: true, false, true, @argument
 sil [ossa] @dont_move_destroy_value_of_moveonly_struct : $@convention(thin) (@owned MoS) -> () {
 entry(%instance : @owned $MoS):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
   %empty = function_ref @empty : $@convention(thin) () -> ()
   apply %empty() : $@convention(thin) () -> ()
   destroy_value %instance : $MoS
@@ -199,16 +199,16 @@ entry(%instance : @owned $MoS):
   return %retval : $()
 }
 
-// CHECK-LABEL: begin running test {{.*}} on dont_move_destroy_value_of_moveonly_enum: canonicalize_ossa_lifetime with: true, false, true, @argument
+// CHECK-LABEL: begin running test {{.*}} on dont_move_destroy_value_of_moveonly_enum: ossa_canonicalize_lifetime with: true, false, true, @argument
 // CHECK-LABEL: sil [ossa] @dont_move_destroy_value_of_moveonly_enum : {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[INSTANCE:%[^,]+]] :
 // CHECK:         apply
 // CHECK:         destroy_value [[INSTANCE]]
 // CHECK-LABEL: } // end sil function 'dont_move_destroy_value_of_moveonly_enum'
-// CHECK-LABEL: end running test {{.*}} on dont_move_destroy_value_of_moveonly_enum: canonicalize_ossa_lifetime with: true, false, true, @argument
+// CHECK-LABEL: end running test {{.*}} on dont_move_destroy_value_of_moveonly_enum: ossa_canonicalize_lifetime with: true, false, true, @argument
 sil [ossa] @dont_move_destroy_value_of_moveonly_enum : $@convention(thin) (@owned MoE) -> () {
 entry(%instance : @owned $MoE):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
   %empty = function_ref @empty : $@convention(thin) () -> ()
   apply %empty() : $@convention(thin) () -> ()
   destroy_value %instance : $MoE
@@ -230,7 +230,7 @@ entry(%instance : @owned $MoE):
 // CHECK-LABEL: end running test 1 of 1 on respect_boundary_edges_when_extending_to_deinit_barriers
 sil [ossa] @respect_boundary_edges_when_extending_to_deinit_barriers : $@convention(thin) (@owned C) -> () {
 entry(%instance : @owned $C):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   apply %barrier() : $@convention(thin) () -> ()
   cond_br undef, die, destroy
@@ -258,7 +258,7 @@ destroy:
 // CHECK-LABEL: end running test {{.*}} on respect_boundary_edges_when_extending_to_deinit_barriers_2
 sil [ossa] @respect_boundary_edges_when_extending_to_deinit_barriers_2 : $@convention(thin) (@owned C) -> () {
 entry(%instance : @owned $C):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   apply %barrier() : $@convention(thin) () -> ()
   cond_br undef, die, destroy
@@ -291,7 +291,7 @@ destroy:
 // CHECK-LABEL: end running test {{.*}} on respect_boundary_edges_when_extending_to_deinit_barriers_3
 sil [ossa] @respect_boundary_edges_when_extending_to_deinit_barriers_3 : $@convention(thin) (@owned C) -> () {
 entry(%instance : @owned $C):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   apply %barrier() : $@convention(thin) () -> ()
   cond_br undef, die, destroy
@@ -323,7 +323,7 @@ destroy:
 // CHECK-LABEL: end running test 1 of 1 on respect_preexisting_destroy_values_when_extending_to_deinit_barriers
 sil [ossa] @respect_preexisting_destroy_values_when_extending_to_deinit_barriers : $@convention(thin) (@owned C) -> () {
 entry(%instance : @owned $C):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   cond_br undef, die, destroy
 
@@ -345,7 +345,7 @@ destroy:
 // CHECK-LABEL: end running test {{.*}} on preserve_dead_end_1
 sil [ossa] @preserve_dead_end_1 : $@convention(thin) () -> () {
 entry:
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
 
   %get = function_ref @getOwned : $@convention(thin) () -> @owned C
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
@@ -363,7 +363,7 @@ entry:
 // CHECK-LABEL: end running test {{.*}} on preserve_dead_end_2
 sil [ossa] @preserve_dead_end_2 : $@convention(thin) () -> () {
 entry:
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
 
   %get = function_ref @getOwned : $@convention(thin) () -> @owned C
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
@@ -386,7 +386,7 @@ entry:
 // CHECK-LABEL: end running test {{.*}} on preserve_dead_end_3
 sil [ossa] @preserve_dead_end_3 : $@convention(thin) () -> () {
 entry:
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
 
   %get = function_ref @getOwned : $@convention(thin) () -> @owned C
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
@@ -411,7 +411,7 @@ die:
 // CHECK-LABEL: end running test {{.*}} on preserve_dead_end_4
 sil [ossa] @preserve_dead_end_4 : $@convention(thin) () -> () {
 entry:
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
 
   %get = function_ref @getOwned : $@convention(thin) () -> @owned C
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
@@ -441,7 +441,7 @@ die:
 // CHECK-LABEL: end running test {{.*}} on preserve_dead_end_5
 sil [ossa] @preserve_dead_end_5 : $@convention(thin) () -> () {
 entry:
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
 
   %get = function_ref @getOwned : $@convention(thin) () -> @owned C
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
@@ -464,7 +464,7 @@ entry:
 // CHECK-LABEL: end running test {{.*}} on preserve_dead_end_6
 sil [ossa] @preserve_dead_end_6 : $@convention(thin) () -> () {
 entry:
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
 
   %get = function_ref @getOwned : $@convention(thin) () -> @owned C
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
@@ -493,7 +493,7 @@ die2:
 // CHECK-LABEL: end running test {{.*}} on preserve_dead_end_7
 sil [ossa] @preserve_dead_end_7 : $@convention(thin) () -> () {
 entry:
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
 
   %get = function_ref @getOwned : $@convention(thin) () -> @owned C
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
@@ -516,7 +516,7 @@ die2:
 }
 
 // (1) When no end is specified, the lifetime ends after the barrier.
-// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_1: canonicalize_ossa_lifetime
+// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_1: ossa_canonicalize_lifetime
 // CHECK-LABEL: sil [ossa] @lexical_end_at_end_1 : {{.*}} {
 // CHECK:       bb0([[C1:%[^,]+]] :
 // CHECK:         [[TAKE_C:%[^,]+]] = function_ref @takeC
@@ -527,9 +527,9 @@ die2:
 // CHECK:         apply [[BARRIER]]()
 // CHECK:         destroy_value [[C1]]
 // CHECK-LABEL: } // end sil function 'lexical_end_at_end_1'
-// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_1: canonicalize_ossa_lifetime
+// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_1: ossa_canonicalize_lifetime
 // (2) When the move_value is specified as a lexical-lifetime-end, the lifetime doesn't extend to the destroy.
-// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_1: canonicalize_ossa_lifetime
+// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_1: ossa_canonicalize_lifetime
 // CHECK-LABEL: sil [ossa] @lexical_end_at_end_1 : {{.*}} {
 // CHECK:       bb0([[C1:%[^,]+]] :
 // CHECK:         [[TAKE_C:%[^,]+]] = function_ref @takeC
@@ -538,11 +538,11 @@ die2:
 // CHECK:         apply [[TAKE_C]]([[M]])
 // CHECK:         apply [[BARRIER]]()
 // CHECK-LABEL: } // end sil function 'lexical_end_at_end_1'
-// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_1: canonicalize_ossa_lifetime
+// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_1: ossa_canonicalize_lifetime
 sil [ossa] @lexical_end_at_end_1 : $@convention(thin) (@owned C) -> () {
 entry(%c1 : @owned $C):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
-  specify_test "canonicalize_ossa_lifetime true false true @argument %m"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument %m"
   %takeC = function_ref @takeC : $@convention(thin) (@owned C) -> ()
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   %c2 = copy_value %c1 : $C
@@ -555,7 +555,7 @@ entry(%c1 : @owned $C):
 }
 
 // (1) When no end is specified, the lifetime ends after the barrier.
-// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_2: canonicalize_ossa_lifetime
+// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_2: ossa_canonicalize_lifetime
 // CHECK-LABEL: sil [ossa] @lexical_end_at_end_2 : {{.*}} {
 // CHECK:       bb0([[C1:%[^,]+]] :
 // CHECK:         [[TAKE_C:%[^,]+]] = function_ref @takeC
@@ -573,11 +573,11 @@ entry(%c1 : @owned $C):
 // CHECK:         apply [[BARRIER]]()
 // CHECK:         destroy_value [[C1]]
 // CHECK-LABEL: } // end sil function 'lexical_end_at_end_2'
-// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_2: canonicalize_ossa_lifetime
+// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_2: ossa_canonicalize_lifetime
 // (2) When the move_value is specified as a lexical-lifetime-end, the lifetime
 //     doesn't extend to the destroy.  But it DOES extend beyond barriers in
 //     blocks where unaffected by the move_value.
-// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_2: canonicalize_ossa_lifetime
+// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_2: ossa_canonicalize_lifetime
 // CHECK-LABEL: sil [ossa] @lexical_end_at_end_2 : {{.*}} {
 // CHECK:       bb0([[C1:%[^,]+]] : @owned $C):
 // CHECK:         [[TAKE_C:%[^,]+]] = function_ref @takeC
@@ -594,11 +594,11 @@ entry(%c1 : @owned $C):
 // CHECK:       [[EXIT]]:
 // CHECK:         apply [[BARRIER]]()
 // CHECK-LABEL: } // end sil function 'lexical_end_at_end_2'
-// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_2: canonicalize_ossa_lifetime
+// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_2: ossa_canonicalize_lifetime
 sil [ossa] @lexical_end_at_end_2 : $@convention(thin) (@owned C) -> () {
 entry(%c1 : @owned $C):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
-  specify_test "canonicalize_ossa_lifetime true false true @argument %m"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument %m"
   %takeC = function_ref @takeC : $@convention(thin) (@owned C) -> ()
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   cond_br undef, left, right
@@ -618,7 +618,7 @@ exit:
 }
 
 // Check barriers on branching unconsumed paths are respected.
-// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_3: canonicalize_ossa_lifetime
+// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_3: ossa_canonicalize_lifetime
 // CHECK-LABEL: sil [ossa] @lexical_end_at_end_3 : {{.*}} {
 // CHECK:       bb0([[C1:%[^,]+]] :
 // CHECK:         [[TAKE_C:%[^,]+]] = function_ref @takeC
@@ -645,8 +645,8 @@ exit:
 // CHECK:         apply [[BARRIER]]()
 // CHECK:         destroy_value [[C1]]
 // CHECK-LABEL: } // end sil function 'lexical_end_at_end_3'
-// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_3: canonicalize_ossa_lifetime
-// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_3: canonicalize_ossa_lifetime
+// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_3: ossa_canonicalize_lifetime
+// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_3: ossa_canonicalize_lifetime
 // CHECK-LABEL: sil [ossa] @lexical_end_at_end_3 : {{.*}} {
 // CHECK:       bb0([[C1:%[^,]+]] :
 // CHECK:         [[TAKE_C:%[^,]+]] = function_ref @takeC
@@ -672,11 +672,11 @@ exit:
 // CHECK:       bb6:
 // CHECK:         apply [[BARRIER]]()
 // CHECK-LABEL: } // end sil function 'lexical_end_at_end_3'
-// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_3: canonicalize_ossa_lifetime
+// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_3: ossa_canonicalize_lifetime
 sil [ossa] @lexical_end_at_end_3 : $@convention(thin) (@owned C) -> () {
 entry(%c1 : @owned $C):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
-  specify_test "canonicalize_ossa_lifetime true false true @argument %m"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument %m"
   %takeC = function_ref @takeC : $@convention(thin) (@owned C) -> ()
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   cond_br undef, left, right_top
@@ -704,7 +704,7 @@ exit:
   return %retval : $()
 }
 
-// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_4: canonicalize_ossa_lifetime
+// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_4: ossa_canonicalize_lifetime
 // CHECK-LABEL: sil [ossa] @lexical_end_at_end_4 : {{.*}} {
 // CHECK:       bb0([[C1:%[^,]+]] :
 // CHECK:         [[TAKE_C:%[^,]+]] = function_ref @takeC
@@ -732,8 +732,8 @@ exit:
 // CHECK:         apply [[BARRIER]]()
 // CHECK:         destroy_value [[C1]]
 // CHECK-LABEL: } // end sil function 'lexical_end_at_end_4'
-// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_4: canonicalize_ossa_lifetime
-// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_4: canonicalize_ossa_lifetime
+// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_4: ossa_canonicalize_lifetime
+// CHECK-LABEL: begin running test {{.*}} on lexical_end_at_end_4: ossa_canonicalize_lifetime
 // CHECK-LABEL: sil [ossa] @lexical_end_at_end_4 : {{.*}} {
 // CHECK:       bb0([[C1:%[^,]+]] :
 // CHECK:         [[TAKE_C:%[^,]+]] = function_ref @takeC : $@convention(thin) (@owned C) -> ()
@@ -759,11 +759,11 @@ exit:
 // CHECK:       [[EXIT]]:
 // CHECK:         apply [[BARRIER]]()
 // CHECK-LABEL: } // end sil function 'lexical_end_at_end_4'
-// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_4: canonicalize_ossa_lifetime
+// CHECK-LABEL: end running test {{.*}} on lexical_end_at_end_4: ossa_canonicalize_lifetime
 sil [ossa] @lexical_end_at_end_4 : $@convention(thin) (@owned C) -> () {
 entry(%c1 : @owned $C):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
-  specify_test "canonicalize_ossa_lifetime true false true @argument %m %m2"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument %m %m2"
   %takeC = function_ref @takeC : $@convention(thin) (@owned C) -> ()
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   cond_br undef, left, right_top
@@ -800,7 +800,7 @@ exit:
 sil [ossa] @dead_arg_debug_dead_end : $@convention(thin) (@owned C) -> () {
 entry(%c : @owned $C):
   debug_value %c : $C
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
   unreachable
 }
 
@@ -817,7 +817,7 @@ bb0(%instance : @owned $C):
   br bb1(%instance : $C, %borrow : $C)
 
 bb1(%instance2 : @owned $C, %reborrowed : @reborrow $C):
-  specify_test "canonicalize_ossa_lifetime true false true %instance2"
+  specify_test "ossa_canonicalize_lifetime true false true %instance2"
   %reborrow = borrowed %reborrowed : $C from (%instance2 : $C)
   cond_br undef, bb2, bb3
 
@@ -847,7 +847,7 @@ bb0(%instance : @owned $C):
   br bb1(%instance : $C, %borrow : $C)
 
 bb1(%instance2 : @owned $C, %reborrowed : @reborrow $C):
-  specify_test "canonicalize_ossa_lifetime true false true %instance2"
+  specify_test "ossa_canonicalize_lifetime true false true %instance2"
   %reborrow = borrowed %reborrowed : $C from (%instance2 : $C)
   cond_br undef, bb2, bb3
 
@@ -889,7 +889,7 @@ exit:
 die:
   %move = move_value [lexical] %c
   %copy = copy_value %move
-  specify_test "canonicalize_ossa_lifetime true false true %move"
+  specify_test "ossa_canonicalize_lifetime true false true %move"
   apply undef(%move) : $@convention(thin) (@owned C) -> ()
   %addr = alloc_stack $C
   %token = store_borrow %copy to %addr
@@ -916,7 +916,7 @@ exit:
 die:
   %move = move_value %c
   %copy = copy_value %move
-  specify_test "canonicalize_ossa_lifetime true false true %move"
+  specify_test "ossa_canonicalize_lifetime true false true %move"
   apply undef(%move) : $@convention(thin) (@owned C) -> ()
   %addr = alloc_stack $C
   %token = store_borrow %copy to %addr
@@ -945,7 +945,7 @@ sil [ossa] @destroy_after_pa_copy_destroy : $@convention(thin) (@owned C) -> ()
 entry(%a: @owned $C):
   // To defeat deinit barriers (apply undef).
   %c = move_value %a
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
 
   %callee = function_ref @borrowC : $@convention(thin) (@guaranteed C) -> ()
   %pa = partial_apply [callee_guaranteed] [on_stack] %callee(%c) : $@convention(thin) (@guaranteed C) -> ()
@@ -967,7 +967,7 @@ entry(%a: @owned $C):
 // CHECK-LABEL: end running test {{.*}} on extend_lifetime_to_deadend_despite_copy_consume
 sil [ossa] @extend_lifetime_to_deadend_despite_copy_consume : $@convention(thin) (@owned C) -> () {
 entry(%c : @owned $C):
-  specify_test "canonicalize_ossa_lifetime true false true @argument"
+  specify_test "ossa_canonicalize_lifetime true false true @argument"
   %cc = copy_value %c
   %takeC = function_ref @takeC : $@convention(thin) (@owned C) -> ()
   apply %takeC(%cc) : $@convention(thin) (@owned C) -> ()
@@ -989,7 +989,7 @@ entry:
   %getPointer = function_ref @getPointer : $@convention(thin) () -> (@owned Pointer)
   %c = apply %getC() : $@convention(thin) () -> (@owned C)
   %pointer = apply %getPointer() : $@convention(thin) () -> (@owned Pointer)
-  specify_test "canonicalize_ossa_lifetime true false true %c"
+  specify_test "ossa_canonicalize_lifetime true false true %c"
   %rawPointer = struct_extract %pointer, #Pointer.rawValue
   %o = pointer_to_address %rawPointer to [strict] $*Int32
   %dependent = mark_dependence [nonescaping] %o on %c
diff --git a/test/SILOptimizer/capture_promotion_attr.sil b/test/SILOptimizer/capture_promotion_attr.sil
index b976f6004ee13..7bc2d342d650e 100644
--- a/test/SILOptimizer/capture_promotion_attr.sil
+++ b/test/SILOptimizer/capture_promotion_attr.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -capture-prop | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -constant-capture-propagation | %FileCheck %s
 
 sil_stage raw
 
diff --git a/test/SILOptimizer/capture_promotion_attrs.sil b/test/SILOptimizer/capture_promotion_attrs.sil
index 9615d573a993c..1504f8ca3d614 100644
--- a/test/SILOptimizer/capture_promotion_attrs.sil
+++ b/test/SILOptimizer/capture_promotion_attrs.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -capture-prop | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -constant-capture-propagation | %FileCheck %s
 
 sil_stage raw
 
diff --git a/test/SILOptimizer/capture_propagate_keypath.swift b/test/SILOptimizer/capture_propagate_keypath.swift
index 4e398f1db7698..2441a774888e3 100644
--- a/test/SILOptimizer/capture_propagate_keypath.swift
+++ b/test/SILOptimizer/capture_propagate_keypath.swift
@@ -38,6 +38,15 @@ struct GetID<C: RandomAccessCollection, ID> {
   }
 }
 
+struct GetInt<C: RandomAccessCollection>  {
+  var getInt: (C.Element) -> Int
+
+  @inline(__always)
+  init(keyPath: KeyPath<C.Element, Int>, i: Int) {
+    getInt = { $0[keyPath: keyPath] + i }
+  }
+}
+
 // CHECK-LABEL: sil {{.*}} @$s4test0A6SimpleyyySiAA3StrVXEXEF :
 // CHECK-NOT:     keypath
 // CHECK-LABEL:  } // end sil function '$s4test0A6SimpleyyySiAA3StrVXEXEF'
@@ -60,12 +69,25 @@ func testGenStr(_ mymap: ((GenStr<Int>)->Int) -> ()) {
 
 // CHECK-LABEL: sil {{.*}} @$s4test0A22GenericEscapingClosureAA5GetIDVySayAA3StrVGSiGyF :
 // CHECK-NOT:     keypath
+// CHECK:         = function_ref @[[SPECIALIZED_CLOSURE:.*]] : $@convention(thin) (@in_guaranteed Str) -> @out Int
+// CHECK-NOT:     keypath
 // CHECK-LABEL:  } // end sil function '$s4test0A22GenericEscapingClosureAA5GetIDVySayAA3StrVGSiGyF'
 @inline(never)
 func testGenericEscapingClosure() -> GetID<[Str], Int> {
     GetID(id: \.i)
 } 
 
+// CHECK-LABEL: sil {{.*}} @$s4test0A22KeypathWithNonConstInt1iAA03GetF0VySayAA3StrVGGSi_tF :
+// CHECK-NOT:     keypath
+// CHECK:         [[C:%.*]] = function_ref @[[SPECIALIZED_CLOSURE2:.*]] : $@convention(thin) (@in_guaranteed Str, Int) -> Int
+// CHECK-NEXT:    partial_apply [callee_guaranteed] [[C]](%0) : $@convention(thin) (@in_guaranteed Str, Int) -> Int
+// CHECK-NOT:     keypath
+// CHECK-LABEL:  } // end sil function '$s4test0A22KeypathWithNonConstInt1iAA03GetF0VySayAA3StrVGGSi_tF'
+@inline(never)
+func testKeypathWithNonConstInt(i: Int) -> GetInt<[Str]> {
+  GetInt(keyPath: \.j, i: i)
+} 
+
 // CHECK-LABEL: sil {{.*}} @$s4test0A7GenericyyyxAA6GenStrVyxGXEXElF :
 // CHECK:         keypath
 // CHECK:         keypath
@@ -85,6 +107,14 @@ public func _opaqueIdentity<T>(_ x: T) -> T {
   return x
 }
 
+// CHECK:       sil shared {{.*}}@[[SPECIALIZED_CLOSURE]] :
+// CHECK-NOT:     keypath
+// CHECK:       } // end sil function '[[SPECIALIZED_CLOSURE]]'
+
+// CHECK:       sil shared {{.*}}@[[SPECIALIZED_CLOSURE2]] :
+// CHECK-NOT:     keypath
+// CHECK:       } // end sil function '[[SPECIALIZED_CLOSURE2]]'
+
 func calltests() {
   // CHECK-OUTPUT-LABEL: testSimple:
   print("testSimple:")
@@ -124,6 +154,12 @@ func calltests() {
 
   // CHECK-OUTPUT-NEXT:  27
   print(testGenericEscapingClosure().getID(Str()))
+
+  // CHECK-OUTPUT-LABEL: testKeypathWithNonConstInt:
+  print("testKeypathWithNonConstInt:")
+
+  // CHECK-OUTPUT-NEXT:  38
+  print(testKeypathWithNonConstInt(i: 10).getInt(Str()))
 }
 
 calltests()
diff --git a/test/SILOptimizer/capture_propagation.sil b/test/SILOptimizer/capture_propagation.sil
index ce04304bbf62f..ca308e6c63c98 100644
--- a/test/SILOptimizer/capture_propagation.sil
+++ b/test/SILOptimizer/capture_propagation.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -capture-prop | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -constant-capture-propagation | %FileCheck %s
 
 // Check the CapturePropagation specialized the reabstraction thunk.
 
@@ -515,7 +515,12 @@ struct Str {
 sil @calleeWithKeypath : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Int) -> ()
 
 // CHECK-LABEL: sil @testKeypath
-// CHECK-NOT:     keypath
+// CHECK:         %0 = keypath
+// CHECK:         strong_release %0
+// CHECK:         [[S:%.*]] = function_ref @$s18closureWithKeypath{{.*}}4main3StrVSiTf3npk_n : $@convention(thin) (Str) -> Int
+// CHECK:         [[T:%.*]] = thin_to_thick_function [[S]]
+// CHECK:         [[C:%.*]] = convert_escape_to_noescape [[T]]
+// CHECK:         apply {{%[0-9]+}}([[C]])
 // CHECK:       } // end sil function 'testKeypath'
 sil @testKeypath : $@convention(thin) () -> () {
 bb0:
@@ -531,7 +536,13 @@ bb0:
 }
 
 // CHECK-LABEL: sil @testCastKeypath :
-// CHECK-NOT:     keypath
+// CHECK:         %0 = keypath
+// CHECK:         [[U:%.*]] = upcast %0
+// CHECK:         strong_release [[U]]
+// CHECK:         [[S:%.*]] = function_ref @$s18closureWithKeypath{{.*}}4main3StrVSiTf3npk_n : $@convention(thin) (Str) -> Int
+// CHECK:         [[T:%.*]] = thin_to_thick_function [[S]]
+// CHECK:         [[C:%.*]] = convert_escape_to_noescape [[T]]
+// CHECK:         apply {{%[0-9]+}}([[C]])
 // CHECK:       } // end sil function 'testCastKeypath'
 sil @testCastKeypath : $@convention(thin) () -> () {
 bb0:
@@ -547,6 +558,29 @@ bb0:
   return %7 : $()
 }
 
+// CHECK-LABEL: sil @dontPropagateMulitUseKeyPathInNonOSSA :
+// CHECK:         %0 = keypath
+// CHECK:         [[U:%.*]] = upcast %0
+// CHECK:         [[C:%.*]] = function_ref @closureWithKeypath
+// CHECK:         partial_apply [callee_guaranteed] [[C]]([[U]])
+// CHECK:       } // end sil function 'dontPropagateMulitUseKeyPathInNonOSSA'
+sil @dontPropagateMulitUseKeyPathInNonOSSA : $@convention(thin) () -> () {
+bb0:
+  %0 = keypath $WritableKeyPath<Str, Int>, (root $Str; stored_property #Str.a : $Int)
+  %c = upcast %0 to $KeyPath<Str, Int>
+  %1 = function_ref @closureWithKeypath : $@convention(thin) (Str, @guaranteed KeyPath<Str, Int>) -> Int
+  %2 = partial_apply [callee_guaranteed] %1(%c) : $@convention(thin) (Str, @guaranteed KeyPath<Str, Int>) -> Int
+  strong_retain %0
+  %3 = convert_escape_to_noescape %2 : $@callee_guaranteed (Str) -> Int to $@noescape @callee_guaranteed (Str) -> Int
+  %4 = function_ref @calleeWithKeypath : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Int) -> ()
+  %5 = apply %4(%3) : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Int) -> ()
+  strong_release %2 : $@callee_guaranteed (Str) -> Int
+  strong_release %0
+  %7 = tuple ()
+  return %7 : $()
+}
+
+
 // CHECK-LABEL: sil shared @$s18closureWithKeypath{{.*}}main3StrVSiTf3npk_n : $@convention(thin) (Str) -> Int {
 // CHECK:         [[K:%[0-9]+]] = keypath
 // CHECK:         [[F:%[0-9]+]] = function_ref @swift_getAtKeyPath
@@ -566,8 +600,13 @@ bb0(%0 : $Str, %1 : $KeyPath<Str, Int>):
   return %9 : $Int
 }
 
-// CHECK-LABEL: sil [ossa] @testKeypathOSSA
-// CHECK-NOT:     keypath
+// CHECK-LABEL: sil [ossa] @testKeypathOSSA :
+// CHECK:         %0 = keypath
+// CHECK:         destroy_value %0
+// CHECK:         [[S:%.*]] = function_ref @$s22closureWithKeypathOSSA{{.*}}4main3StrVSiTf3npk_n : $@convention(thin) (Str) -> Int
+// CHECK:         [[T:%.*]] = thin_to_thick_function [[S]]
+// CHECK:         [[C:%.*]] = convert_escape_to_noescape [[T]]
+// CHECK:         apply {{%[0-9]+}}([[C]])
 // CHECK:       } // end sil function 'testKeypathOSSA'
 sil [ossa] @testKeypathOSSA : $@convention(thin) () -> () {
 bb0:
@@ -584,7 +623,13 @@ bb0:
 }
 
 // CHECK-LABEL: sil [ossa] @testCastKeypathOSSA :
-// CHECK-NOT:     keypath
+// CHECK:         %0 = keypath
+// CHECK:         [[U:%.*]] = upcast %0
+// CHECK:         destroy_value [[U]]
+// CHECK:         [[S:%.*]] = function_ref @$s22closureWithKeypathOSSA{{.*}}4main3StrVSiTf3npk_n : $@convention(thin) (Str) -> Int
+// CHECK:         [[T:%.*]] = thin_to_thick_function [[S]]
+// CHECK:         [[C:%.*]] = convert_escape_to_noescape [[T]]
+// CHECK:         apply {{%[0-9]+}}([[C]])
 // CHECK:       } // end sil function 'testCastKeypathOSSA'
 sil [ossa] @testCastKeypathOSSA : $@convention(thin) () -> () {
 bb0:
@@ -602,7 +647,14 @@ bb0:
 }
 
 // CHECK-LABEL: sil [ossa] @testCastKeypathOSSA2 :
-// CHECK-NOT:     keypath
+// CHECK:         %0 = keypath
+// CHECK:         [[O:%.*]] = open_existential_ref %0
+// CHECK:         [[U:%.*]] = upcast [[O]]
+// CHECK:         destroy_value [[U]]
+// CHECK:         [[S:%.*]] = function_ref @$s22closureWithKeypathOSSA{{.*}}4main3StrVSiTf3npk_n : $@convention(thin) (Str) -> Int
+// CHECK:         [[T:%.*]] = thin_to_thick_function [[S]]
+// CHECK:         [[C:%.*]] = convert_escape_to_noescape [[T]]
+// CHECK:         apply {{%[0-9]+}}([[C]])
 // CHECK:       } // end sil function 'testCastKeypathOSSA2'
 sil [ossa] @testCastKeypathOSSA2 : $@convention(thin) () -> () {
 bb0:
@@ -660,4 +712,229 @@ bb0(%0 : $Str, %1 : @guaranteed $KeyPath<Str, Int>):
   return %9 : $Int
 }
 
+// CHECK-LABEL: sil [ossa] @testKeypathWithNonConst :
+// CHECK:         %1 = keypath
+// CHECK:         destroy_value %1
+// CHECK:         [[S:%.*]] = function_ref @$s24closureWithKeypathAndInt{{.*}}4main3StrVSiTf3npkn_n : $@convention(thin) (Str, Int) -> Int
+// CHECK:         [[P:%.*]] = partial_apply [callee_guaranteed] [[S]](%0) : $@convention(thin) (Str, Int) -> Int
+// CHECK:         [[C:%.*]] = convert_escape_to_noescape [[P]]
+// CHECK:         apply {{%[0-9]+}}([[C]])
+// CHECK:       } // end sil function 'testKeypathWithNonConst'
+sil [ossa] @testKeypathWithNonConst : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = keypath $KeyPath<Str, Int>, (root $Str; stored_property #Str.a : $Int)
+  %2 = function_ref @closureWithKeypathAndInt : $@convention(thin) (Str, @guaranteed KeyPath<Str, Int>, Int) -> Int
+  %3 = partial_apply [callee_guaranteed] %2(%1, %0) : $@convention(thin) (Str, @guaranteed KeyPath<Str, Int>, Int) -> Int
+  %4 = convert_escape_to_noescape %3 : $@callee_guaranteed (Str) -> Int to $@noescape @callee_guaranteed (Str) -> Int
+  %5 = function_ref @calleeWithKeypath : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Int) -> ()
+  %6 = apply %5(%4) : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Int) -> ()
+  destroy_value %4 : $@noescape @callee_guaranteed (Str) -> Int
+  destroy_value %3 : $@callee_guaranteed (Str) -> Int
+  %8 = tuple ()
+  return %8 : $()
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s24closureWithKeypathAndInt{{.*}}4main3StrVSiTf3npkn_n : $@convention(thin) (Str, Int) -> Int {
+// CHECK:         [[K:%[0-9]+]] = keypath
+// CHECK:         [[F:%[0-9]+]] = function_ref @swift_getAtKeyPath
+// CHECK:         apply [[F]]<Str, Int>({{%[0-9]+, %[0-9]+}}, [[K]]
+// CHECK:         destroy_value [[K]]
+// CHECK:       } // end sil function '$s24closureWithKeypathAndInt{{.*}}4main3StrVSiTf3npkn_n'
+sil [ossa] @closureWithKeypathAndInt : $@convention(thin) (Str, @guaranteed KeyPath<Str, Int>, Int) -> Int {
+bb0(%0 : $Str, %1 : @guaranteed $KeyPath<Str, Int>, %2 : $Int):
+  %4 = alloc_stack $Str
+  store %0 to [trivial] %4 : $*Str
+  %6 = function_ref @swift_getAtKeyPath : $@convention(thin) <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @guaranteed KeyPath<τ_0_0, τ_0_1>) -> @out τ_0_1
+  %7 = alloc_stack $Int
+  %8 = apply %6<Str, Int>(%7, %4, %1) : $@convention(thin) <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @guaranteed KeyPath<τ_0_0, τ_0_1>) -> @out τ_0_1
+  %9 = load [trivial] %7 : $*Int
+  dealloc_stack %7 : $*Int
+  dealloc_stack %4 : $*Str
+  return %9 : $Int
+}
+
+// CHECK-LABEL: sil [ossa] @testKeypathWithNonConstGeneric :
+// CHECK:         %1 = keypath
+// CHECK:         destroy_value %1
+// CHECK:         [[S:%.*]] = function_ref @$s22closureWithKeypathAndT{{.*}}4main3StrVSiTf3npkn_n : $@convention(thin) (Str, @in_guaranteed Int) -> Int
+// CHECK:         [[P:%.*]] = partial_apply [callee_guaranteed] [[S]](%0) : $@convention(thin) (Str, @in_guaranteed Int) -> Int
+// CHECK:         [[C:%.*]] = convert_escape_to_noescape [[P]]
+// CHECK:         apply {{%[0-9]+}}([[C]])
+// CHECK:       } // end sil function 'testKeypathWithNonConstGeneric'
+sil [ossa] @testKeypathWithNonConstGeneric : $@convention(thin) (@in Int) -> () {
+bb0(%0 : $*Int):
+  %1 = keypath $KeyPath<Str, Int>, (root $Str; stored_property #Str.a : $Int)
+  %2 = function_ref @closureWithKeypathAndT : $@convention(thin) <τ_0_0> (Str, @guaranteed KeyPath<Str, Int>, @in_guaranteed τ_0_0) -> Int
+  %3 = partial_apply [callee_guaranteed] %2<Int>(%1, %0) : $@convention(thin) <τ_0_0> (Str, @guaranteed KeyPath<Str, Int>, @in_guaranteed τ_0_0) -> Int
+  %4 = convert_escape_to_noescape %3 : $@callee_guaranteed (Str) -> Int to $@noescape @callee_guaranteed (Str) -> Int
+  %5 = function_ref @calleeWithKeypath : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Int) -> ()
+  %6 = apply %5(%4) : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Int) -> ()
+  destroy_value %4 : $@noescape @callee_guaranteed (Str) -> Int
+  destroy_value %3 : $@callee_guaranteed (Str) -> Int
+  %8 = tuple ()
+  return %8 : $()
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s22closureWithKeypathAndT{{.*}}4main3StrVSiTf3npkn_n : $@convention(thin) (Str, @in_guaranteed Int) -> Int {
+// CHECK:         [[K:%[0-9]+]] = keypath
+// CHECK:         [[F:%[0-9]+]] = function_ref @swift_getAtKeyPath
+// CHECK:         apply [[F]]<Str, Int>({{%[0-9]+, %[0-9]+}}, [[K]]
+// CHECK:         destroy_value [[K]]
+// CHECK:       } // end sil function '$s22closureWithKeypathAndT{{.*}}4main3StrVSiTf3npkn_n'
+sil [ossa] @closureWithKeypathAndT : $@convention(thin) <T> (Str, @guaranteed KeyPath<Str, Int>, @in_guaranteed T) -> Int {
+bb0(%0 : $Str, %1 : @guaranteed $KeyPath<Str, Int>, %2 : $*T):
+  %4 = alloc_stack $Str
+  store %0 to [trivial] %4 : $*Str
+  %6 = function_ref @swift_getAtKeyPath : $@convention(thin) <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @guaranteed KeyPath<τ_0_0, τ_0_1>) -> @out τ_0_1
+  %7 = alloc_stack $Int
+  %8 = apply %6<Str, Int>(%7, %4, %1) : $@convention(thin) <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @guaranteed KeyPath<τ_0_0, τ_0_1>) -> @out τ_0_1
+  %9 = load [trivial] %7 : $*Int
+  dealloc_stack %7 : $*Int
+  dealloc_stack %4 : $*Str
+  return %9 : $Int
+}
+
+sil @useIntClosure : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Builtin.Int32) -> ()
+
+// CHECK-LABEL: sil [ossa] @dontSpecializeConstAndNonConst :
+// CHECK:         %1 = integer_literal $Builtin.Int32, 3
+// CHECK:         %2 = function_ref @closureWithTwoInts :
+// CHECK:         %3 = partial_apply [callee_guaranteed] %2(%1, %0) :
+// CHECK:       } // end sil function 'dontSpecializeConstAndNonConst'
+sil [ossa] @dontSpecializeConstAndNonConst : $@convention(thin) (Builtin.Int32) -> () {
+bb0(%0 : $Builtin.Int32):
+  %1 = integer_literal $Builtin.Int32, 3
+  %2 = function_ref @closureWithTwoInts : $@convention(thin) (Str, Builtin.Int32, Builtin.Int32) -> Builtin.Int32
+  %3 = partial_apply [callee_guaranteed] %2(%1, %0) : $@convention(thin) (Str, Builtin.Int32, Builtin.Int32) -> Builtin.Int32
+  %4 = convert_escape_to_noescape %3 to $@noescape @callee_guaranteed (Str) -> Builtin.Int32
+  %5 = function_ref @useIntClosure : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Builtin.Int32) -> ()
+  %6 = apply %5(%4) : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Builtin.Int32) -> ()
+  destroy_value %4
+  destroy_value %3
+  %8 = tuple ()
+  return %8 : $()
+}
+
+sil [ossa] @closureWithTwoInts : $@convention(thin) (Str, Builtin.Int32, Builtin.Int32) -> Builtin.Int32 {
+bb0(%0 : $Str, %1 : $Builtin.Int32, %2 : $Builtin.Int32):
+  return %1
+}
+
+struct S {
+  let i: Int32
+  let b: Bool
+}
+
+// CHECK-LABEL: sil [ossa] @testStruct :
+// CHECK:         [[C:%.*]] = function_ref @$s17closureWithStruct4main1SVs5Int32VSbTf3npSSi3Si0_n : $@convention(thin) (Str) -> Builtin.Int32
+// CHECK:         thin_to_thick_function [[C]] : $@convention(thin) (Str) -> Builtin.Int32 to $@callee_guaranteed (Str) -> Builtin.Int32
+// CHECK:       } // end sil function 'testStruct'
+sil [ossa] @testStruct : $@convention(thin) () -> () {
+bb0:
+  %0 = integer_literal $Builtin.Int32, 3
+  %1 = struct $Int32 (%0)
+  %2 = integer_literal $Builtin.Int1, 0
+  %3 = struct $Bool (%2)
+  %4 = struct $S (%1, %3)
+  %5 = function_ref @closureWithStruct : $@convention(thin) (Str, S) -> Builtin.Int32
+  %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (Str, S) -> Builtin.Int32
+  %7 = convert_escape_to_noescape %6 to $@noescape @callee_guaranteed (Str) -> Builtin.Int32
+  %8 = function_ref @useIntClosure : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Builtin.Int32) -> ()
+  %9 = apply %8(%7) : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Builtin.Int32) -> ()
+  destroy_value %7
+  destroy_value %6
+  %12 = tuple ()
+  return %12 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @testNonConstStruct1 :
+// CHECK:         [[S:%.*]] = struct $S
+// CHECK:         partial_apply [callee_guaranteed] {{%[0-9]+}}([[S]])
+// CHECK:       } // end sil function 'testNonConstStruct1'
+sil [ossa] @testNonConstStruct1 : $@convention(thin) (Int32) -> () {
+bb0(%0 : $Int32):
+  %2 = integer_literal $Builtin.Int1, 0
+  %3 = struct $Bool (%2)
+  %4 = struct $S (%0, %3)
+  %5 = function_ref @closureWithStruct : $@convention(thin) (Str, S) -> Builtin.Int32
+  %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (Str, S) -> Builtin.Int32
+  %7 = convert_escape_to_noescape %6 to $@noescape @callee_guaranteed (Str) -> Builtin.Int32
+  %8 = function_ref @useIntClosure : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Builtin.Int32) -> ()
+  %9 = apply %8(%7) : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Builtin.Int32) -> ()
+  destroy_value %7
+  destroy_value %6
+  %12 = tuple ()
+  return %12 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @testNonConstStruct2 :
+// CHECK:         [[S:%.*]] = struct $S
+// CHECK:         partial_apply [callee_guaranteed] {{%[0-9]+}}([[S]])
+// CHECK:       } // end sil function 'testNonConstStruct2'
+sil [ossa] @testNonConstStruct2 : $@convention(thin) (Bool) -> () {
+bb0(%0 : $Bool):
+  %1 = integer_literal $Builtin.Int32, 3
+  %2 = struct $Int32 (%1)
+  %4 = struct $S (%2, %0)
+  %5 = function_ref @closureWithStruct : $@convention(thin) (Str, S) -> Builtin.Int32
+  %6 = partial_apply [callee_guaranteed] %5(%4) : $@convention(thin) (Str, S) -> Builtin.Int32
+  %7 = convert_escape_to_noescape %6 to $@noescape @callee_guaranteed (Str) -> Builtin.Int32
+  %8 = function_ref @useIntClosure : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Builtin.Int32) -> ()
+  %9 = apply %8(%7) : $@convention(thin) (@noescape @callee_guaranteed (Str) -> Builtin.Int32) -> ()
+  destroy_value %7
+  destroy_value %6
+  %12 = tuple ()
+  return %12 : $()
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s17closureWithStruct4main1SVs5Int32VSbTf3npSSi3Si0_n : $@convention(thin) (Str) -> Builtin.Int32 {
+// CHECK:       bb0(%0 : $Str):
+// CHECK:         %1 = integer_literal $Builtin.Int32, 3
+// CHECK:         %2 = struct $Int32 (%1 : $Builtin.Int32)
+// CHECK:         %3 = integer_literal $Builtin.Int1, 0
+// CHECK:         %4 = struct $Bool (%3 : $Builtin.Int1)
+// CHECK:         %5 = struct $S (%2 : $Int32, %4 : $Bool)
+// CHECK:         %6 = struct_extract %5 : $S, #S.i
+// CHECK:         %7 = struct_extract %6 : $Int32, #Int32._value
+// CHECK:         return %7 : $Builtin.Int32
+// CHECK:       } // end sil function '$s17closureWithStruct4main1SVs5Int32VSbTf3npSSi3Si0_n'
+sil [ossa] @closureWithStruct : $@convention(thin) (Str, S) -> Builtin.Int32 {
+bb0(%0 : $Str, %1 : $S):
+  %2 = struct_extract %1, #S.i
+  %3 = struct_extract %2, #Int32._value
+  return %3
+}
+
 sil @swift_getAtKeyPath : $@convention(thin) <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @guaranteed KeyPath<τ_0_0, τ_0_1>) -> @out τ_0_1
+
+struct NonTrivialStruct {
+    var x: AnyObject
+}
+
+sil_global [serialized] @gNonTrivialStruct : $NonTrivialStruct
+
+// CHECK-LABEL: sil [ossa] @test_global_addr :
+// CHECK:         [[C:%.*]] = function_ref @$s19global_addr_closure17gNonTrivialStructTf3pg_n : $@convention(thin) () -> ()
+// CHECK:         thin_to_thick_function %2 : $@convention(thin) () -> () to $@callee_owned () -> ()
+// CHECK:       } // end sil function 'test_global_addr'
+sil [ossa] @test_global_addr : $@convention(thin) () -> () {
+  %3 = global_addr @gNonTrivialStruct : $*NonTrivialStruct
+  %7 = function_ref @global_addr_closure : $@convention(thin) <T> (@in_guaranteed T) -> ()
+  %8 = partial_apply %7<NonTrivialStruct>(%3) : $@convention(thin) <T> (@in_guaranteed T) -> ()
+  destroy_value %8
+  %r = tuple()
+  return %r
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s19global_addr_closure17gNonTrivialStructTf3pg_n :
+// CHECK:       bb0:
+// CHECK-NEXT:    %0 = global_addr @gNonTrivialStruct : $*NonTrivialStruct
+// CHECK-NEXT:    %1 = tuple ()
+// CHECK-NEXT:    return %1
+// CHECK:       } // end sil function '$s19global_addr_closure17gNonTrivialStructTf3pg_n'
+sil [ossa] @global_addr_closure : $@convention(thin) <T> (@in_guaranteed T) -> () {
+bb0(%0 : $*T):
+  %r = tuple()
+  return %r : $()
+}
+
diff --git a/test/SILOptimizer/cast_folding_no_bridging.sil b/test/SILOptimizer/cast_folding_no_bridging.sil
index d9a85e9810d1f..cdc2e8e4fc59f 100644
--- a/test/SILOptimizer/cast_folding_no_bridging.sil
+++ b/test/SILOptimizer/cast_folding_no_bridging.sil
@@ -64,10 +64,8 @@ bb3:
 sil @fail : $@convention(thin) () -> Never
 
 // CHECK-LABEL: sil {{.*}}@testCFToObjC
-// CHECK: bb0(
-// CHECK-NEXT: [[T0:%.*]] = load %1 : $*CFString
-// CHECK-NEXT: [[T1:%.*]] = unchecked_ref_cast [[T0]] : $CFString to $NSString
-// CHECK-NEXT: store [[T1]] to %0 : $*NSString
+// CHECK:         checked_cast_addr_br
+// CHECK:       } // end sil function 'testCFToObjC'
 sil @testCFToObjC : $@convention(thin) (@in CFString) -> @out NSString {
 bb0(%0 : $*NSString, %1 : $*CFString):
   checked_cast_addr_br take_always CFString in %1 : $*CFString to NSString in %0 : $*NSString, bb1, bb2
@@ -83,11 +81,8 @@ bb2:
 }
 
 // CHECK-LABEL: sil {{.*}}@testCFToSwift
-// CHECK: bb0(
-// CHECK-NEXT: [[T0:%.*]] = load %1 : $*CFString
-// CHECK-NEXT: [[T1:%.*]] = unchecked_ref_cast [[T0]] : $CFString to $NSString
-// CHECK:      [[FN:%.*]] = function_ref @$sSS10FoundationE34_conditionallyBridgeFromObjectiveC_6resultSbSo8NSStringC_SSSgztFZ : $@convention(method) (@guaranteed NSString, @inout Optional<String>, @thin String.Type) -> Bool
-// CHECK: apply [[FN]]([[T1]], {{.*}}, {{.*}})
+// CHECK:         checked_cast
+// CHECK:       } // end sil function 'testCFToSwift'
 sil @testCFToSwift : $@convention(thin) (@in CFString) -> @out String {
 bb0(%0 : $*String, %1 : $*CFString):
   checked_cast_addr_br take_always CFString in %1 : $*CFString to String in %0 : $*String, bb1, bb2
diff --git a/test/SILOptimizer/cast_folding_objc.swift b/test/SILOptimizer/cast_folding_objc.swift
index dfccaa25f7174..026cd55401e16 100644
--- a/test/SILOptimizer/cast_folding_objc.swift
+++ b/test/SILOptimizer/cast_folding_objc.swift
@@ -77,12 +77,9 @@ public func castObjCToSwift<T>(_ t: T) -> Int {
   return t as! Int
 }
 
-// Check that compiler understands that this cast always fails
 // CHECK-LABEL: sil [noinline] {{.*}}@$s17cast_folding_objc37testFailingBridgedCastFromObjCtoSwiftySiSo8NSStringCF
-// CHECK: [[ONE:%[0-9]+]] = integer_literal $Builtin.Int1, -1
-// CHECK: cond_fail [[ONE]] : $Builtin.Int1, "failed cast"
-// CHECK-NEXT: unreachable
-// CHECK-NEXT: }
+// CHECK:         unconditional_checked_cast %0 : $NSString to NSNumber
+// CHECK:       } // end sil function '$s17cast_folding_objc37testFailingBridgedCastFromObjCtoSwiftySiSo8NSStringCF'
 @inline(never)
 public func testFailingBridgedCastFromObjCtoSwift(_ ns: NSString) -> Int {
   return castObjCToSwift(ns)
diff --git a/test/SILOptimizer/closure_specialization.sil b/test/SILOptimizer/closure_specialization.sil
new file mode 100644
index 0000000000000..5c3d776b2d01d
--- /dev/null
+++ b/test/SILOptimizer/closure_specialization.sil
@@ -0,0 +1,949 @@
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all -closure-specialization %s | %FileCheck %s
+
+sil_stage canonical
+
+import Builtin
+import Swift
+
+// CHECK-LABEL: sil shared [noinline] [ossa] @$s7specgen12take_closureyyySi_SitcF023$s7specgen6calleryySiFyE8_SitcfU_SiTf1c_n : $@convention(thin) (Int) -> () {
+
+// CHECK: bb0(%0 : $Int)
+// CHECK: function_ref @$s7specgen6calleryySiFySi_SitcfU_
+// CHECK: partial_apply
+
+// CHECK-LABEL: sil shared [noinline] [ossa] @$s7specgen12take_closureyyySi_SitcF26$s7specgen6calleeyySi_SitFTf1c_n : $@convention(thin) () -> () {
+// CHECK-NEXT: bb0:
+// CHECK: [[FUN:%.*]] = function_ref @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> ()
+// CHECK: thin_to_thick_function [[FUN]] : $@convention(thin) (Int, Int) -> () to $@callee_owned (Int, Int) -> ()
+
+// CHECK-LABEL: sil [noinline] [ossa] @$s7specgen12take_closureyyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () {
+sil [ossa] [noinline] @$s7specgen12take_closureyyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () {
+bb0(%0 : @owned $@callee_owned (Int, Int) -> ()):
+  %2 = load [trivial] undef : $*Int
+  %3 = apply %0(%2, %2) : $@callee_owned (Int, Int) -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil shared [noinline] [ossa] @$s7specgen13take_closure2yyySi_SitcF023$s7specgen6calleryySiFyE8_SitcfU_SiTf1c_n : $@convention(thin) (Int) -> () {
+// CHECK: bb0(%0 : $Int)
+// CHECK: [[FUN:%.*]] = function_ref @$s7specgen6calleryySiFySi_SitcfU_
+// CHECK: partial_apply [[FUN]](
+
+// CHECK-LABEL: sil shared [noinline] [ossa] @$s7specgen13take_closure2yyySi_SitcF26$s7specgen6calleeyySi_SitFTf1c_n : $@convention(thin) () -> () {
+// CHECK-NEXT: bb0:
+// CHECK: [[FUN:%.*]] = function_ref @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> ()
+// CHECK: thin_to_thick_function [[FUN]] : $@convention(thin) (Int, Int) -> () to $@callee_owned (Int, Int) -> ()
+
+// CHECK-LABEL: sil [noinline] [ossa] @$s7specgen13take_closure2yyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () {
+sil [ossa] [noinline] @$s7specgen13take_closure2yyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () {
+bb0(%0 : @owned $@callee_owned (Int, Int) -> ()):
+  %2 = load [trivial] undef : $*Int
+  %3 = apply %0(%2, %2) : $@callee_owned (Int, Int) -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [noinline] [ossa] @$s7specgen6calleeyySi_S2itF : $@convention(thin) (Int, Int, Int) -> () {
+// specgen.callee (Swift.Int, Swift.Int, Swift.Int) -> ()
+sil [ossa] [noinline] @$s7specgen6calleeyySi_S2itF : $@convention(thin) (Int, Int, Int) -> () {
+bb0(%0 : $Int, %1 : $Int, %2 : $Int):
+  %6 = tuple ()                                   // user: %7
+  return %6 : $()                                 // id: %7
+}
+
+// CHECK-LABEL: sil [ossa] @$s7specgen6calleryySiF : $@convention(thin) (Int) -> () {
+// CHECK: [[ID2:%[0-9]+]] = function_ref @$s7specgen12take_closureyyySi_SitcF023$s7specgen6calleryySiFyE8_SitcfU_SiTf1c_n : $@convention(thin) (Int) -> ()
+// CHECK: apply [[ID2]](%0) : $@convention(thin) (Int) -> ()
+// CHECK: [[ID1:%[0-9]+]] = function_ref @$s7specgen13take_closure2yyySi_SitcF023$s7specgen6calleryySiFyE8_SitcfU_SiTf1c_n : $@convention(thin) (Int) -> ()
+// CHECK: apply [[ID1]](%0) : $@convention(thin) (Int) -> ()
+sil [ossa] @$s7specgen6calleryySiF : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  // function_ref specgen.take_closure ((Swift.Int, Swift.Int) -> ()) -> ()
+  %2 = function_ref @$s7specgen12take_closureyyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () // user: %5
+  // function_ref specgen.(caller (Swift.Int) -> ()).(closure #1)
+  %3 = function_ref @$s7specgen6calleryySiFySi_SitcfU_ : $@convention(thin) (Int, Int, Int) -> () // user: %4
+  %4 = partial_apply %3(%0) : $@convention(thin) (Int, Int, Int) -> () // user: %5
+  %4a = copy_value %4
+  %5 = apply %2(%4a) : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
+  %6 = function_ref @$s7specgen13take_closure2yyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () // user: %5
+  %4b = copy_value %4
+  %7 = apply %6(%4b) : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
+  destroy_value %4
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s7specgen6calleryySiFySi_SitcfU_ : $@convention(thin) (Int, Int, Int) -> () {
+sil shared [ossa] @$s7specgen6calleryySiFySi_SitcfU_ : $@convention(thin) (Int, Int, Int) -> () {
+bb0(%0 : $Int, %1 : $Int, %2 : $Int):
+  %5 = alloc_box $<τ_0_0> { var τ_0_0 } <Int>, var, name "p"                   // users: %6, %10, %14
+  %5a = project_box %5 : $<τ_0_0> { var τ_0_0 } <Int>, 0
+  store %0 to [trivial] %5a : $*Int                        // id: %6
+  %7 = alloc_box $<τ_0_0> { var τ_0_0 } <Int>, var, name "q"                   // users: %8, %11, %13
+  %7a = project_box %7 : $<τ_0_0> { var τ_0_0 } <Int>, 0
+  store %1 to [trivial] %7a : $*Int                        // id: %8
+  // function_ref specgen.callee (Swift.Int, Swift.Int, Swift.Int) -> ()
+  %9 = function_ref @$s7specgen6calleeyySi_S2itF : $@convention(thin) (Int, Int, Int) -> () // user: %12
+  %10 = load [trivial] %5a : $*Int                         // user: %12
+  %11 = load [trivial] %7a : $*Int                         // user: %12
+  %12 = apply %9(%10, %11, %2) : $@convention(thin) (Int, Int, Int) -> ()
+  destroy_value %7
+  destroy_value %5
+  %15 = tuple ()                                  // user: %16
+  return %15 : $()                                // id: %16
+}
+
+//////////////////////////////////
+// Thin To Thick Function Tests //
+//////////////////////////////////
+
+// CHECK-LABEL: sil [noinline] [ossa] @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> () {
+// specgen.callee (Swift.Int, Swift.Int) -> ()
+sil [noinline] [ossa] @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> () {
+bb0(%0 : $Int, %1 : $Int):
+  %6 = tuple ()                                   // user: %7
+  return %6 : $()                                 // id: %7
+}
+
+// CHECK-LABEL: sil [ossa] @$s7specgen11tttficalleryySiF : $@convention(thin) (Int) -> () {
+// CHECK: [[ID2:%[0-9]+]] = function_ref @$s7specgen12take_closureyyySi_SitcF26$s7specgen6calleeyySi_SitFTf1c_n : $@convention(thin) () -> ()
+// CHECK: apply [[ID2]]() : $@convention(thin) () -> ()
+// CHECK: [[ID1:%[0-9]+]] = function_ref @$s7specgen13take_closure2yyySi_SitcF26$s7specgen6calleeyySi_SitFTf1c_n : $@convention(thin) () -> ()
+// CHECK: apply [[ID1]]() : $@convention(thin) () -> ()
+sil [ossa] @$s7specgen11tttficalleryySiF : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  // function_ref specgen.take_closure ((Swift.Int, Swift.Int) -> ()) -> ()
+  %2 = function_ref @$s7specgen12take_closureyyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () // user: %5
+  // function_ref specgen.(caller (Swift.Int) -> ()).(closure #1)
+  %3 = function_ref @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> () // user: %4
+  %4 = thin_to_thick_function %3 : $@convention(thin) (Int, Int) -> () to $@callee_owned (Int, Int) -> () // user: %5
+  %5 = apply %2(%4) : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
+  %6 = function_ref @$s7specgen13take_closure2yyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
+  %7 = apply %6(%4) : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
+  %9999 = tuple ()                                   // user: %7
+  return %9999 : $()                                 // id: %7
+}
+
+// We don't handle closures that close over address types (*NOTE* this includes
+// address and non-address only types) taken as @in or @in_guaranteed.
+
+// This is a temporary limitation.
+// CHECK-LABEL: sil [ossa] @address_closure : $@convention(thin) (@in Int) -> () {
+sil [ossa] @address_closure : $@convention(thin) (@in Int) -> () {
+bb0(%0 : $*Int):
+  %6 = tuple()
+  return %6 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
+sil [ossa] @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
+bb0(%0 : @owned $@callee_owned () -> ()):
+  %1 = apply %0() : $@callee_owned () -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @address_caller : $@convention(thin) (@in Int) -> () {
+// CHECK-NOT: _TTSf1cl15address_closureSi__address_closure_user
+sil [ossa] @address_caller : $@convention(thin) (@in Int) -> () {
+bb0(%0 : $*Int):
+  %1 = function_ref @address_closure : $@convention(thin) (@in Int) -> ()
+  %2 = partial_apply %1(%0) : $@convention(thin) (@in Int) -> ()
+  %3 = function_ref @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  %4 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+class A {}
+
+sil hidden [ossa] [noinline] @closure : $@convention(thin) (@owned A, @owned A) -> () {
+bb0(%0 : @owned $A, %1 : @owned $A):
+  destroy_value %1
+  destroy_value %0
+  %4 = tuple ()
+  return %4 : $()
+}
+
+// CHECK-LABEL: sil shared {{.*}} @$s11use_closure{{.*}}Tf{{.*}} : $@convention(thin) (@owned A) -> () {
+sil hidden [ossa] [noinline] @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> () {
+bb0(%0 : @owned $@callee_owned (@owned A) -> ()):
+  %1 = alloc_ref $A
+  %2 = apply %0(%1) : $@callee_owned (@owned A) -> ()
+  %3 = tuple ()
+  return %3 : $()
+}
+
+// CHECK-LABEL: sil shared {{.*}} @$s17use_closure_throw{{.*}}Tf{{.*}} : $@convention(thin) (@owned A) -> @error any Error {
+sil hidden [ossa] [noinline] @use_closure_throw : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> @error any Error {
+bb0(%0 : @owned $@callee_owned (@owned A) -> ()):
+  %1 = alloc_ref $A
+  %2 = apply %0(%1) : $@callee_owned (@owned A) -> ()
+  %3 = tuple ()
+  return %3 : $()
+}
+
+// CHECK-LABEL: sil {{.*}} @different_execution_counts
+// CHECK: bb0([[ARG:%.*]] : @guaranteed $A
+// CHECK:   %1 = copy_value %0
+// CHECK-NOT: partial_apply
+// CHECK:   [[C:%.*]] = copy_value %1
+// CHECK-NOT: partial_apply
+// CHECK:   integer_literal $Builtin.Int64, 0
+// CHECK:   br bb2
+
+// CHECK: bb1:
+// CHECK:   destroy_value [[C]]
+// CHECK:   destroy_value %1
+// CHECK:   return
+
+// CHECK: bb2({{.*}}):
+// Match the partial_apply consume of arg.
+// CHECK:   [[C2:%.*]] = copy_value [[C]]
+// CHECK:   [[SPECIALIZED_CLOSURE_USER:%.*]] = function_ref @$s11use_closure{{.*}}Tf
+// CHECK:   apply [[SPECIALIZED_CLOSURE_USER]]([[C2]])
+// CHECK:   cond_br {{.*}}, bb1, bb3
+
+sil hidden [ossa] [noinline] @different_execution_counts : $@convention(thin) (@guaranteed A) -> () {
+bb0(%0 : @guaranteed $A):
+  %1 = copy_value %0
+  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
+  %3 = partial_apply %2(%1) : $@convention(thin) (@owned A, @owned A) -> ()
+  %4 = integer_literal $Builtin.Int64, 0
+  %5 = integer_literal $Builtin.Int64, 5
+  %6 = integer_literal $Builtin.Int64, 1
+  %7 = integer_literal $Builtin.Int1, 0
+  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
+  br bb2(%4 : $Builtin.Int64)
+
+bb1:
+  destroy_value %3
+  %11 = tuple ()
+  return %11 : $()
+
+bb2(%13 : $Builtin.Int64):
+  %14 = builtin "sadd_with_overflow_Int64"(%13 : $Builtin.Int64, %6 : $Builtin.Int64, %7 : $Builtin.Int1) : $(Builtin.Int64, Builtin.Int1)
+  %15 = tuple_extract %14 : $(Builtin.Int64, Builtin.Int1), 0
+  %16 = copy_value %3
+  %17 = apply %8(%16) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
+  %18 = builtin "cmp_eq_Int64"(%15 : $Builtin.Int64, %5 : $Builtin.Int64) : $Builtin.Int1
+  cond_br %18, bb1, bb3
+
+bb3:
+  br bb2(%15 : $Builtin.Int64)
+}
+
+// CHECK-LABEL: sil [ossa] @insert_release_in_liverange_exit_block
+// CHECK:       bb0(%0 : @guaranteed $A):
+// CHECK:         %1 = copy_value %0
+// CHECK:         [[C:%.*]] = copy_value %1
+// CHECK:       bb1:
+// CHECK-NEXT:    destroy_value [[C]]
+// CHECK-NEXT:    destroy_value
+// CHECK-NEXT:    br bb3
+// CHECK:       bb2:
+// CHECK:         apply %{{[0-9]+}}([[C]])
+// CHECK:       bb3:
+// CHECK-NOT:     %0
+// CHECK:         return
+sil [ossa] @insert_release_in_liverange_exit_block : $@convention(thin) (@guaranteed A) -> () {
+bb0(%0 : @guaranteed $A):
+  %1 = copy_value %0
+  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
+  %3 = partial_apply %2(%1) : $@convention(thin) (@owned A, @owned A) -> ()
+  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
+  %4 = copy_value %3
+  %5 = partial_apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
+  cond_br undef, bb1, bb2
+
+bb1:
+  destroy_value %4
+  br bb3
+
+bb2:
+  %17 = apply %8(%4) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
+  br bb3
+
+bb3:
+  destroy_value %5
+  %11 = tuple ()
+  return %11 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @insert_release_in_loop_exit_block
+// CHECK: bb0(%0 : @guaranteed $A):
+// CHECK:   %1 = copy_value %0
+// CHECK:   [[C:%.*]] = copy_value %1
+// CHECK: bb1:
+// CHECK-NEXT:   br bb2
+// CHECK: bb2:
+// CHECK:   [[C2:%.*]] = copy_value [[C]]
+// CHECK:   apply %{{[0-9]+}}([[C2]])
+// CHECK-NOT:   %0
+// CHECK: bb4:
+// CHECK-NEXT: destroy_value [[C]]
+// CHECK-NEXT: destroy_value
+// CHECK-NOT: %0
+// CHECK:   return
+sil [ossa] @insert_release_in_loop_exit_block : $@convention(thin) (@guaranteed A) -> () {
+bb0(%0 : @guaranteed $A):
+  %1 = copy_value %0
+  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
+  %3 = partial_apply %2(%1) : $@convention(thin) (@owned A, @owned A) -> ()
+  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
+  %4 = copy_value %3
+  %5 = partial_apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
+  cond_br undef, bb4, bb1
+
+bb1:
+  br bb2
+
+bb2:
+  %16 = copy_value %4
+  %17 = apply %8(%16) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
+  cond_br undef, bb3, bb5
+
+bb3:
+  br bb2
+
+bb4:
+  destroy_value %4
+  br bb6
+
+bb5:
+  destroy_value %4
+  br bb6
+
+bb6:
+  destroy_value %5
+  %11 = tuple ()
+  return %11 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @insert_release_after_try_apply
+// CHECK:       bb0(%0 : @guaranteed $A):
+// CHECK:         %1 = copy_value %0
+// CHECK:         [[C:%.*]] = copy_value %1
+// CHECK:       bb1:
+// CHECK-NEXT:    destroy_value %1
+// CHECK:         try_apply %{{[0-9]+}}([[C]])
+// CHECK:       bb2(%{{[0-9]+}} : $()):
+// CHECK-NEXT:    br bb4
+// CHECK:       bb3(%{{[0-9]+}} : $any Error):
+// CHECK-NEXT:    br bb4
+// CHECK:       bb4:
+// CHECK-NOT:     %0
+// CHECK:   return
+sil [ossa] @insert_release_after_try_apply : $@convention(thin) (@guaranteed A) -> () {
+bb0(%0 : @guaranteed $A):
+  %1 = copy_value %0
+  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
+  %3 = partial_apply %2(%1) : $@convention(thin) (@owned A, @owned A) -> ()
+  %8 = function_ref @use_closure_throw : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> @error Error
+  br bb1
+
+bb1:
+  try_apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> @error Error, normal bb2, error bb3
+
+bb2(%n : $()):
+  br bb4
+
+bb3(%e : $Error):
+  br bb4
+
+bb4:
+  %11 = tuple ()
+  return %11 : $()
+}
+
+
+// Ensure that we can specialize and properly mangle functions that take closures with <τ_0_0> { var τ_0_0 } <arguments>.
+
+// CHECK-LABEL: sil shared [noinline] [ossa] @$s4main5inneryys5Int32Vz_yADctF25closure_with_box_argumentxz_Bi32__lXXTf1nc_n : $@convention(thin) (@inout Builtin.Int32, @owned <τ_0_0> { var τ_0_0 } <Builtin.Int32>) -> ()
+// CHECK: bb0
+// CHECK: [[FN:%.*]] = function_ref @closure_with_box_argument
+// CHECK: [[PARTIAL:%.*]] = partial_apply [[FN]](%1)
+// CHECK: [[C:%.*]] = copy_value [[PARTIAL]]
+// CHECK: [[ARG:%.*]] = load [trivial] %0
+// CHECK: apply [[C]]([[ARG]])
+
+// CHECK-LABEL: {{.*}} @$s4main5inneryys5Int32Vz_yADctF
+sil hidden [ossa] [noinline] @$s4main5inneryys5Int32Vz_yADctF : $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> () {
+bb0(%0 : $*Builtin.Int32, %1 : @owned $@callee_owned (Builtin.Int32) -> ()):
+  %5 = load [trivial] %0 : $*Builtin.Int32
+  %6 = apply %1(%5) : $@callee_owned (Builtin.Int32) -> ()
+  %11 = tuple ()
+  return %11 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @pass_a_closure
+sil [ossa] @pass_a_closure: $@convention(thin) () -> Builtin.Int32 {
+bb0:
+  %0 = alloc_box $<τ_0_0> { var τ_0_0 } <Builtin.Int32>, var, name "i"
+  %0a = project_box %0 : $<τ_0_0> { var τ_0_0 } <Builtin.Int32>, 0
+  %1 = integer_literal $Builtin.Int32, 0
+  store %1 to [trivial] %0a : $*Builtin.Int32
+  %4 = function_ref @closure_with_box_argument : $@convention(thin) (Builtin.Int32, @owned <τ_0_0> { var τ_0_0 } <Builtin.Int32>) -> ()
+  %5 = copy_value %0
+  %6 = partial_apply %4(%5) : $@convention(thin) (Builtin.Int32, @owned <τ_0_0> { var τ_0_0 } <Builtin.Int32>) -> ()
+  %7 = alloc_stack $Builtin.Int32
+  %9 = integer_literal $Builtin.Int32, 1
+  store %9 to [trivial] %7 : $*Builtin.Int32
+  %12 = function_ref @$s4main5inneryys5Int32Vz_yADctF: $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> ()
+  %13 = copy_value %6
+  %14 = apply %12(%7, %13) : $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> ()
+  destroy_value %6
+  %16 = tuple ()
+  dealloc_stack %7 : $*Builtin.Int32
+  %18 = load [trivial] %0a : $*Builtin.Int32
+  destroy_value %0
+  return %18 : $Builtin.Int32
+}
+
+// CHECK-LABEL: sil shared [ossa] @closure_with_box_argument
+sil shared [ossa] @closure_with_box_argument : $@convention(thin) (Builtin.Int32, @owned <τ_0_0> { var τ_0_0 } <Builtin.Int32>) -> () {
+bb0(%0 : $Builtin.Int32, %1 : @owned $<τ_0_0> { var τ_0_0 } <Builtin.Int32>):
+  %3 = project_box %1 : $<τ_0_0> { var τ_0_0 } <Builtin.Int32>, 0
+  store %0 to [trivial] %3 : $*Builtin.Int32
+  destroy_value %1
+  %7 = tuple ()
+  return %7 : $()
+}
+
+// Check that we don't crash with this:
+// CHECK-LABEL: sil [ossa] @test_box_with_named_elements_tuple
+sil [ossa] @test_box_with_named_elements_tuple: $@convention(thin) () -> Builtin.Int32 {
+bb0:
+  %0 = alloc_box ${ let (first: Builtin.Int32, second: Builtin.Int32) }
+  %0p = project_box %0 : ${ let (first: Builtin.Int32, second: Builtin.Int32) }, 0
+  %0a = tuple_element_addr %0p : $*(first: Builtin.Int32, second: Builtin.Int32), 0
+  %0b = tuple_element_addr %0p : $*(first: Builtin.Int32, second: Builtin.Int32), 1
+  %1 = integer_literal $Builtin.Int32, 0
+  store %1 to [trivial] %0a : $*Builtin.Int32
+  store %1 to [trivial] %0b : $*Builtin.Int32
+  %4 = function_ref @closure_with_named_elements_tuple : $@convention(thin) (Builtin.Int32, @owned { let (first: Builtin.Int32, second: Builtin.Int32) }) -> ()
+  %5 = copy_value %0
+  %6 = partial_apply %4(%5) : $@convention(thin) (Builtin.Int32, @owned { let (first: Builtin.Int32, second: Builtin.Int32) }) -> ()
+  %7 = alloc_stack $Builtin.Int32
+  %9 = integer_literal $Builtin.Int32, 1
+  store %9 to [trivial] %7 : $*Builtin.Int32
+  %12 = function_ref @$s4main5inneryys5Int32Vz_yADctF: $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> ()
+  %13 = copy_value %6
+  %14 = apply %12(%7, %13) : $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> ()
+  destroy_value %6
+  %16 = tuple ()
+  dealloc_stack %7 : $*Builtin.Int32
+  %18 = load [trivial] %0a : $*Builtin.Int32
+  destroy_value %0
+  return %18 : $Builtin.Int32
+}
+
+// CHECK-LABEL: sil shared [ossa] @closure_with_named_elements_tuple
+sil shared [ossa] @closure_with_named_elements_tuple : $@convention(thin) (Builtin.Int32, @owned { let (first: Builtin.Int32, second: Builtin.Int32) }) -> () {
+bb0(%0 : $Builtin.Int32, %1 : @owned ${ let (first: Builtin.Int32, second: Builtin.Int32) }):
+  %3 = project_box %1 : ${ let (first: Builtin.Int32, second: Builtin.Int32) }, 0
+  %4 = tuple_element_addr %3 : $*(first: Builtin.Int32, second: Builtin.Int32), 0
+  store %0 to [trivial] %4 : $*Builtin.Int32
+  destroy_value %1
+  %7 = tuple ()
+  return %7 : $()
+}
+
+
+// The specialized function should always be a thin function, regardless of the
+// representation of the original function.
+
+public protocol P {
+  static func foo(cl: () -> Int) -> Int
+}
+
+public struct S : P {
+  public static func foo(cl: () -> Int) -> Int
+  init()
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s4test1SVAA1PA2aDP3fooyS2iycFZTW8closure2SiTf1cn_n : $@convention(thin) (@thick S.Type, Int) -> Int
+sil [ossa] @$s4test1SVAA1PA2aDP3fooyS2iycFZTW : $@convention(witness_method: P) (@guaranteed @noescape @callee_guaranteed () -> Int, @thick S.Type) -> Int {
+bb0(%0 : @guaranteed $@noescape @callee_guaranteed () -> Int, %1 : $@thick S.Type):
+  %3 = apply %0() : $@noescape @callee_guaranteed () -> Int
+  return %3 : $Int
+}
+
+sil shared [ossa] @closure2 : $@convention(thin) (Int) -> Int {
+bb0(%0 : $Int):
+  return %0 : $Int
+}
+
+sil [ossa] @call_witness_method : $@convention(thin) (Int, S) -> Int {
+bb0(%0 : $Int, %1 : $S):
+  %3 = function_ref @closure2 : $@convention(thin) (Int) -> Int
+  %4 = partial_apply [callee_guaranteed] %3(%0) : $@convention(thin) (Int) -> Int
+  %4a = convert_escape_to_noescape %4 : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
+  %5 = metatype $@thick S.Type
+  %6 = function_ref @$s4test1SVAA1PA2aDP3fooyS2iycFZTW : $@convention(witness_method: P) (@guaranteed @noescape @callee_guaranteed () -> Int, @thick S.Type) -> Int
+  %7 = apply %6(%4a, %5) : $@convention(witness_method: P) (@guaranteed @noescape @callee_guaranteed () -> Int, @thick S.Type) -> Int
+  destroy_value %4a
+  destroy_value %4
+  return %7 : $Int
+}
+
+sil_witness_table S: P module test {
+  method #P.foo: @$s4test1SVAA1PA2aDP3fooyS2iycFZTW
+}
+
+// Test partial_apply -> convert_function -> convert_function -> try_apply.
+sil [ossa] @testClosureConvertHelper : $(Int) -> ()
+
+// specialized testClosureConvertThunk
+// FIXME: Need to handle closures with multiple exceptional exits.
+// CHECK-LABEL: sil shared [ossa] @$s23testClosureConvertThunk0abC6HelperSiTf1nc_n : $@convention(thin) (Int) -> (@out (), @error any Error) {
+// CHECK:       bb0(%0 : $*(), %1 : $Int):
+// CHECK:         [[F:%.*]] = function_ref @testClosureConvertHelper : $@convention(thin) (Int) -> ()
+// CHECK:         [[PA:%.*]] = partial_apply [[F]](%1) : $@convention(thin) (Int) -> ()
+// CHECK:         [[CVT1:%.*]] = convert_escape_to_noescape [[PA]] : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+// CHECK:         [[CVT2:%.*]] = convert_function [[CVT1]] : $@noescape @callee_owned () -> () to $@noescape @callee_owned () -> @error any Error
+// CHECK:         [[C:%.*]] = copy_value [[CVT2]]
+// CHECK:         try_apply [[C]]() : $@noescape @callee_owned () -> @error any Error, normal bb1, error bb2
+// CHECK:       bb1
+// CHECK:         destroy_value [[CVT2]]
+// CHECK:         destroy_value [[PA]]
+// CHECK:         return
+// CHECK:       bb2
+// CHECK:         destroy_value [[CVT2]]
+// CHECK:         destroy_value [[PA]]
+// CHECK:         throw
+// CHECK-LABEL: } // end sil function '$s23testClosureConvertThunk0abC6HelperSiTf1nc_n'
+sil [ossa] @testClosureConvertThunk : $@convention(thin) (@guaranteed @noescape @callee_owned () -> @error Error) -> (@out (), @error Error) {
+bb0(%0 : $*(), %1 : @guaranteed $@noescape @callee_owned () -> @error Error):
+  %2 = copy_value %1
+  try_apply %2() : $@noescape @callee_owned () -> @error Error, normal bb1, error bb2
+
+bb1(%7 : $()):
+  %8 = tuple ()
+  return %8 : $()
+
+bb2(%10 : $Error):
+  throw %10 : $Error
+}
+
+// Test closure specialization when the closure type is converted before application.
+sil [ossa] @testClosureConvert : $(Int) -> () {
+bb0(%0 : $Int):
+  %48 = alloc_stack $()
+  %49 = function_ref @testClosureConvertHelper : $@convention(thin) (Int) -> ()
+  %50 = partial_apply %49(%0) : $@convention(thin) (Int) -> ()
+  %51 = convert_escape_to_noescape %50 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+  %52 = convert_function %51 : $@noescape @callee_owned () -> () to $@noescape @callee_owned () -> @error Error
+  %53 = function_ref @testClosureConvertThunk : $@convention(thin) (@guaranteed @noescape @callee_owned () -> @error Error) -> (@out (), @error Error)
+  try_apply %53(%48, %52) : $@convention(thin) (@guaranteed @noescape @callee_owned () -> @error Error) -> (@out (), @error Error), normal bb7, error bb11
+
+bb7(%callret : $()):
+  br bb99
+
+bb11(%128 : $Error):
+  br bb99
+
+bb99:
+  destroy_value %52
+  destroy_value %50
+  dealloc_stack %48 : $*()
+  %empty = tuple ()
+  return %empty : $()
+}
+
+sil [ossa] @testClosureThunkNoEscape : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> ()) -> () {
+bb0(%0 : @guaranteed $@noescape @callee_guaranteed () -> ()):
+  apply %0() : $@noescape @callee_guaranteed () -> ()
+  %8 = tuple ()
+  return %8 : $()
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s24testClosureThunkNoEscape0aB13ConvertHelperSiTf1c_n : $@convention(thin) (Int) -> () {
+// CHECK: bb0([[ARG:%.*]] : $Int):
+// CHECK:   [[F:%.*]] = function_ref @testClosureConvertHelper : $@convention(thin) (Int) -> ()
+// CHECK:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[F]]([[ARG]]) : $@convention(thin) (Int) -> ()
+// CHECK:   [[E:%.*]] = convert_escape_to_noescape [[PA]] : $@callee_guaranteed () -> () to $@noescape @callee_guaranteed () -> ()
+// CHECK:   apply [[E]]() : $@noescape @callee_guaranteed () -> ()
+// CHECK:   destroy_value [[E]]
+// CHECK:   destroy_value [[PA]]
+// CHECK:   return
+// CHECK: }
+// CHECK-LABEL: sil [ossa] @testClosureNoEscape : $@convention(thin) (Int) -> () {
+// CHECK-NOT: partial_apply
+// CHECK:   [[FN:%.*]] = function_ref @$s24testClosureThunkNoEscape0aB13ConvertHelperSiTf1c_n : $@convention(thin) (Int) -> ()
+// CHECK-NOT: partial_apply
+// CHECK:   %5 = apply [[FN]](%0) : $@convention(thin) (Int) -> ()
+// CHECK-NOT: release
+// CHECK:   return
+// CHECK: }
+
+sil [ossa] @testClosureNoEscape : $(Int) -> () {
+bb0(%0 : $Int):
+  %48 = alloc_stack $()
+  %49 = function_ref @testClosureConvertHelper : $@convention(thin) (Int) -> ()
+  %50 = partial_apply [callee_guaranteed] %49(%0) : $@convention(thin) (Int) -> ()
+  %51 = convert_escape_to_noescape %50 : $@callee_guaranteed () -> () to $@noescape @callee_guaranteed () -> ()
+  %53 = function_ref @testClosureThunkNoEscape : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> ()) -> ()
+  apply %53(%51) : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> ()) -> ()
+  destroy_value %50
+  destroy_value %51
+  dealloc_stack %48 : $*()
+  %empty = tuple ()
+  return %empty : $()
+}
+
+
+sil [ossa] @testClosureConvertHelper2 : $(Int) -> Int
+
+sil [ossa] @testClosureThunkNoEscape2 : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> @out Int) -> @out Int {
+bb0(%0 : $*Int, %1 : @guaranteed $@noescape @callee_guaranteed () -> @out Int):
+  apply %1(%0) : $@noescape @callee_guaranteed () -> @out Int
+  %8 = tuple ()
+  return %8 : $()
+}
+
+sil [reabstraction_thunk] @reabstractionThunk : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+
+// CHECK-LABEL: sil shared [ossa] @$s25testClosureThunkNoEscape20aB14ConvertHelper2SiTf1nc_n : $@convention(thin) (Int) -> @out Int
+// CHECK: [[PA1:%.*]] = partial_apply
+// CHECK: convert_escape_to_noescape
+// CHECK: [[PA2:%.*]] = partial_apply
+// CHECK: [[CE:%.*]] = convert_escape_to_noescape
+// CHECK: apply
+// CHECK: destroy_value [[CE]]
+// CHECK: destroy_value [[PA2]]
+// CHECK: destroy_value [[PA1]]
+// CHECK: return
+
+// CHECK-LABEL: sil [ossa] @reabstractionTest : $@convention(thin) (Int) -> ()
+// CHECK: [[F:%.*]] = function_ref @$s25testClosureThunkNoEscape20aB14ConvertHelper2SiTf1nc_n
+// CHECK: apply [[F]]
+// CHECK: return
+sil [ossa] @reabstractionTest : $(Int) -> () {
+bb0(%0 : $Int):
+  %48 = alloc_stack $Int
+  %49 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
+  %50 = partial_apply [callee_guaranteed] %49(%0) : $@convention(thin) (Int) -> Int
+  %51 = convert_escape_to_noescape %50 : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
+  %52 = function_ref @reabstractionThunk : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+  %53 = partial_apply [callee_guaranteed] %52(%51) : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+  %54 = convert_escape_to_noescape %53 : $@callee_guaranteed () -> @out Int to $@noescape @callee_guaranteed () -> @out Int
+  %55 = function_ref @testClosureThunkNoEscape2 : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> @out Int) -> @out Int
+  apply %55(%48, %54) : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> @out Int) -> @out Int
+  destroy_value %50
+  destroy_value %53
+  destroy_value %54
+  dealloc_stack %48 : $*Int
+  %empty = tuple ()
+  return %empty : $()
+}
+
+sil [ossa] @testClosureConvertHelper3 : $@convention(thin) (Int) -> Int
+sil [reabstraction_thunk] @reabstractionThunk3 : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+
+sil [ossa] @testClosureThunkNoEscape3 : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>) -> @out () {
+entry(%empty : $*(), %closure : @owned $@noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>):
+  %out = alloc_stack $Int
+  %ret = apply %closure(%out) : $@noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>
+  dealloc_stack %out : $*Int
+  store %ret to [trivial] %empty : $*()
+  destroy_value %closure
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: sil [ossa] @reabstractionTest4 {{.*}} {
+// CHECK:         [[HELPER:%[^,]+]] = function_ref @testClosureConvertHelper3
+// CHECK:         [[CLOSURE:%[^,]+]] = partial_apply [callee_guaranteed] [[HELPER]]
+// CHECK:         [[NOESCAPE_CLOSURE:%[^,]+]] = convert_escape_to_noescape [[CLOSURE]]
+// CHECK:         [[SPECIALIZATION:%[^,]+]] = function_ref @$s25testClosureThunkNoEscape30aB14ConvertHelper3SiTf1nc_n
+// CHECK:         apply [[SPECIALIZATION]]{{.*}}
+// CHECK:         destroy_value [[CLOSURE]]
+// CHECK:         destroy_value [[NOESCAPE_CLOSURE]]
+// CHECK-LABEL: } // end sil function 'reabstractionTest4'
+sil [ossa] @reabstractionTest4 : $(Int) -> () {
+bb0(%value : $Int):
+  %testThrowingClosureConvertHelper = function_ref @testClosureConvertHelper3 : $@convention(thin) (Int) -> Int
+  %closure = partial_apply [callee_guaranteed] %testThrowingClosureConvertHelper(%value) : $@convention(thin) (Int) -> Int
+  %noescapeClosure = convert_escape_to_noescape %closure : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
+  %thunk = function_ref @reabstractionThunk3 : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+  %appliedThunk = partial_apply [callee_guaranteed] [on_stack] %thunk(%noescapeClosure) : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+
+  %dependency = mark_dependence %appliedThunk : $@noescape @callee_guaranteed () -> @out Int on %noescapeClosure : $@noescape @callee_guaranteed () -> Int
+  %generified = convert_function %dependency : $@noescape @callee_guaranteed () -> @out Int to $@noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>
+  %test = function_ref @testClosureThunkNoEscape3 : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>) -> @out ()
+  %out = alloc_stack $()
+  %ret = apply %test(%out, %generified) : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>) -> @out ()
+  dealloc_stack %out : $*()
+  destroy_value %closure
+  destroy_value %noescapeClosure
+  %empty = tuple ()
+  return %empty : $()
+}
+
+sil [ossa] @testThrowingClosureConvertHelper : $@convention(thin) (Int) -> (Int, @error any Error)
+sil [reabstraction_thunk] @reabstractionThunkThrowing : $@convention(thin) (@noescape @callee_guaranteed () -> (Int, @error any Error)) -> (@out Int, @error any Error)
+
+sil [ossa] @testClosureThunkNoEscapeThrowing : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>) -> (@out (), @error any Error) {
+entry(%empty : $*(), %closure : @owned $@noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>):
+  %out = alloc_stack $Int
+  try_apply %closure(%out) : $@noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>, normal bb1, error bb2
+
+bb1(%ret : $()):
+  destroy_value %closure
+  dealloc_stack %out : $*Int
+  store %ret to [trivial] %empty : $*()
+  %retval = tuple ()
+  return %retval : $()
+
+bb2(%error : $any Error):
+  destroy_value %closure
+  dealloc_stack %out : $*Int
+  throw %error : $any Error
+}
+
+// CHECK-LABEL: sil [ossa] @reabstractionThrowing : $@convention(thin) (Int) -> ((), @error any Error) {
+// CHECK:         [[HELPER:%[^,]+]] = function_ref @testThrowingClosureConvertHelper
+// CHECK:         [[CLOSURE:%[^,]+]] = partial_apply [callee_guaranteed] [[HELPER]]
+// CHECK:         [[NOESCAPE_CLOSURE:%[^,]+]] = convert_escape_to_noescape [[CLOSURE]]
+// CHECK:         [[SPECIALIZATION:%[^,]+]] = function_ref @$s32testClosureThunkNoEscapeThrowing0afB13ConvertHelperSiTf1nc_n
+// CHECK:         try_apply [[SPECIALIZATION]]{{.*}}normal [[NORMAL_BLOCK:bb[0-9]+]], error [[ERROR_BLOCK:bb[0-9]+]]
+// CHECK:       [[NORMAL_BLOCK]]
+// CHECK:         destroy_value [[NOESCAPE_CLOSURE]]
+// CHECK:         destroy_value [[CLOSURE]]
+// CHECK:       [[ERROR_BLOCK]]
+// CHECK:         destroy_value [[NOESCAPE_CLOSURE]]
+// CHECK:         destroy_value [[CLOSURE]]
+// CHECK-LABEL: } // end sil function 'reabstractionThrowing'
+sil [ossa] @reabstractionThrowing : $(Int) -> ((), @error any Error) {
+bb0(%value : $Int):
+  %testThrowingClosureConvertHelper = function_ref @testThrowingClosureConvertHelper : $@convention(thin) (Int) -> (Int, @error any Error)
+  %closure = partial_apply [callee_guaranteed] %testThrowingClosureConvertHelper(%value) : $@convention(thin) (Int) -> (Int, @error any Error)
+  %noescapeClosure = convert_escape_to_noescape %closure : $@callee_guaranteed () -> (Int, @error any Error) to $@noescape @callee_guaranteed () -> (Int, @error any Error)
+  %thunk = function_ref @reabstractionThunkThrowing : $@convention(thin) (@noescape @callee_guaranteed () -> (Int, @error any Error)) -> (@out Int, @error any Error)
+  %appliedThunk = partial_apply [callee_guaranteed] [on_stack] %thunk(%noescapeClosure) : $@convention(thin) (@noescape @callee_guaranteed () -> (Int, @error any Error)) -> (@out Int, @error any Error)
+
+  %dependency = mark_dependence %appliedThunk : $@noescape @callee_guaranteed () -> (@out Int, @error any Error) on %noescapeClosure : $@noescape @callee_guaranteed () -> (Int, @error any Error)
+  %generified = convert_function %dependency : $@noescape @callee_guaranteed () -> (@out Int, @error any Error) to $@noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>
+  %test = function_ref @testClosureThunkNoEscapeThrowing : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>) -> (@out (), @error any Error)
+  %out = alloc_stack $()
+  try_apply %test(%out, %generified) : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>) -> (@out (), @error any Error), normal bb1, error bb2
+
+bb1(%ret : $()):
+  dealloc_stack %out : $*()
+  destroy_value %noescapeClosure
+  destroy_value %closure
+  %empty = tuple ()
+  return %empty : $()
+
+bb2(%error : $any Error):
+  dealloc_stack %out : $*()
+  destroy_value %noescapeClosure
+  destroy_value %closure
+  throw %error : $any Error
+}
+
+// Currently not supported cases.
+
+sil [ossa] @testClosureThunk4 : $@convention(thin) (@owned @callee_guaranteed () -> @out Int) -> @out Int {
+bb0(%0 : $*Int, %1 : @owned $@callee_guaranteed () -> @out Int):
+  apply %1(%0) : $@callee_guaranteed () -> @out Int
+  destroy_value %1
+  %8 = tuple ()
+  return %8 : $()
+}
+// CHECK-LABEL: sil [ossa] @reabstractionTest2
+// CHECK: bb0(%0 : $Int):
+// CHECK: [[STK:%.*]] = alloc_stack $Int
+// CHECK: [[F:%.*]] = function_ref @testClosureConvertHelper2
+// CHECK: [[PA:%.*]] = partial_apply [callee_guaranteed] [[F]](%0)
+// CHECK: [[CVT:%.*]] = convert_escape_to_noescape [[PA]]
+// CHECK: [[F2:%.*]] = function_ref @reabstractionThunk
+// CHECK: [[PA2:%.*]] = partial_apply [callee_guaranteed] [[F2]]([[CVT]])
+// CHECK: [[F3:%.*]] = function_ref @$s17testClosureThunk40aB14ConvertHelper2SiTf1nc_n : $@convention(thin) (Int) -> @out Int
+// CHECK:  apply [[F3]]([[STK]], %0)
+// CHECK:  destroy_value [[PA]]
+// CHECK:  dealloc_stack [[STK]]
+// CHECK:  return
+
+sil [ossa] @reabstractionTest2 : $(Int) -> () {
+bb0(%0 : $Int):
+  %48 = alloc_stack $Int
+  %49 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
+  %50 = partial_apply [callee_guaranteed] %49(%0) : $@convention(thin) (Int) -> Int
+  %51 = convert_escape_to_noescape %50 : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
+  %52 = function_ref @reabstractionThunk : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+  %53 = partial_apply [callee_guaranteed] %52(%51) : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+  %55 = function_ref @testClosureThunk4 : $@convention(thin) (@owned @callee_guaranteed () -> @out Int) -> @out Int
+  apply %55(%48, %53) : $@convention(thin) (@owned @callee_guaranteed () -> @out Int) -> @out Int
+  destroy_value %50
+  dealloc_stack %48 : $*Int
+  %empty = tuple ()
+  return %empty : $()
+}
+
+// Only support the ultimate partial_apply.
+sil [reabstraction_thunk] @reabstractionThunk2 : $@convention(thin) (@guaranteed @callee_guaranteed () -> Int) -> @out Int
+
+// CHECK-LABEL: sil [ossa] @reabstractionTest3 : $@convention(thin) (Int) -> () {
+// CHECK: bb0(%0 : $Int):
+// CHECK:  [[STK:%.*]] = alloc_stack $Int
+// CHECK:  [[SPEC:%.*]] = function_ref @$s25testClosureThunkNoEscape20aB14ConvertHelper2SiTf1nc_n : $@convention(thin) (Int) -> @out Int // user: %9
+// CHECK:    = apply [[SPEC]]([[STK]], %0) : $@convention(thin) (Int) -> @out Int
+// CHECK:  dealloc_stack [[STK]] : $*Int
+// CHECK:  return
+
+sil [ossa] @reabstractionTest3 : $(Int) -> () {
+bb0(%0 : $Int):
+  %48 = alloc_stack $Int
+  %49 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
+  %50 = partial_apply [callee_guaranteed] %49(%0) : $@convention(thin) (Int) -> Int
+  %52 = function_ref @reabstractionThunk2 : $@convention(thin) (@guaranteed @callee_guaranteed () -> Int) -> @out Int
+  %53 = partial_apply [callee_guaranteed] %52(%50) : $@convention(thin) (@guaranteed @callee_guaranteed () -> Int) -> @out Int
+  %54 = convert_escape_to_noescape %53 : $@callee_guaranteed () -> @out Int to $@noescape @callee_guaranteed () -> @out Int
+  %55 = function_ref @testClosureThunkNoEscape2 : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> @out Int) -> @out Int
+  apply %55(%48, %54) : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> @out Int) -> @out Int
+  destroy_value %54
+  destroy_value %53
+  dealloc_stack %48 : $*Int
+  %empty = tuple ()
+  return %empty : $()
+}
+
+//////////////////////
+// Begin Apply Test //
+//////////////////////
+
+sil [ossa] @coroutine_user : $@yield_once @convention(thin) (@guaranteed @noescape @callee_guaranteed () -> Int) -> @yields Int {
+bb0(%0 : @guaranteed $@noescape @callee_guaranteed () -> Int):
+  %1 = apply %0() : $@noescape @callee_guaranteed () -> Int
+  unreachable
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s14coroutine_user25testClosureConvertHelper2SiTf1c_n : $@yield_once @convention(thin) (Int) -> @yields Int {
+
+// CHECK-LABEL: sil [ossa] @test_coroutine_user : $@convention(thin) (Int) -> Int {
+// CHECK:         [[C:%.*]] = function_ref @$s14coroutine_user25testClosureConvertHelper2SiTf1c_n : $@yield_once @convention(thin) (Int) -> @yields Int
+// CHECK:           = begin_apply [[C]](%0)
+// CHECK: } // end sil function 'test_coroutine_user'
+sil [ossa] @test_coroutine_user : $@convention(thin) (Int) -> Int {
+bb0(%0 : $Int):
+  %1 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
+  %2 = partial_apply [callee_guaranteed] %1(%0) : $@convention(thin) (Int) -> Int
+  %3 = convert_escape_to_noescape %2 : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
+  %4 = function_ref @coroutine_user : $@yield_once @convention(thin) (@guaranteed @noescape @callee_guaranteed () -> Int) -> @yields Int
+  (%value, %token) = begin_apply %4(%3) : $@yield_once @convention(thin) (@guaranteed @noescape @callee_guaranteed () -> Int) -> @yields Int
+  cond_br undef, bb1, bb2
+
+bb1:
+  end_apply %token as $()
+  destroy_value %3
+  br bb3
+
+bb2:
+  abort_apply %token
+  destroy_value %3
+  br bb3
+
+bb3:
+  destroy_value %2
+  return %value : $Int
+}
+
+// CHECK-LABEL: sil [ossa] @reabstractionTest_on_stack
+// CHECK: bb0([[A:%.*]] : $Int):
+// CHECK:  [[R:%.*]] = alloc_stack $Int
+// CHECK:  [[F:%.*]] = function_ref @$s25testClosureThunkNoEscape20aB14ConvertHelper2SiTf1nc_n
+// CHECK: apply [[F]]([[R]], [[A]])
+sil [ossa] @reabstractionTest_on_stack : $(Int) -> () {
+bb0(%0 : $Int):
+  %48 = alloc_stack $Int
+  %49 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
+  %50 = partial_apply [callee_guaranteed] [on_stack] %49(%0) : $@convention(thin) (Int) -> Int
+  %52 = function_ref @reabstractionThunk : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+  %53 = partial_apply [callee_guaranteed] [on_stack] %52(%50) : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
+  %55 = function_ref @testClosureThunkNoEscape2 : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> @out Int) -> @out Int
+  apply %55(%48, %53) : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> @out Int) -> @out Int
+  destroy_value %53 : $@noescape @callee_guaranteed () -> @out Int
+  destroy_value %50 : $@noescape @callee_guaranteed () -> Int
+  dealloc_stack %48 : $*Int
+  %empty = tuple ()
+  return %empty : $()
+}
+
+sil [ossa] @closure_with_string : $@convention(thin) (@guaranteed String) -> ()
+
+sil [ossa] @use_non_escaping_closure : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> ()) -> () {
+bb0(%0 : @guaranteed $@noescape @callee_guaranteed () -> ()):
+  %2 = apply %0() : $@noescape @callee_guaranteed () -> ()
+  %3 = tuple ()
+  return %3 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @non_trivial_arg_capture : {{.*}} {
+// CHECK-NOT:     retain_value {{%.*}} : $String
+// CHECK-LABEL: } // end sil function 'non_trivial_arg_capture'
+sil [ossa] @non_trivial_arg_capture : $@convention(thin) (@guaranteed String) -> () {
+bb0(%nc : @guaranteed $String):
+  %closure_fn = function_ref @closure_with_string : $@convention(thin) (@guaranteed String) -> ()
+  %closure = partial_apply [callee_guaranteed] [on_stack] %closure_fn(%nc) : $@convention(thin) (@guaranteed String) -> ()
+  %use = function_ref @use_non_escaping_closure : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> ()) -> ()
+  apply %use(%closure) : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> ()) -> ()
+  destroy_value %closure
+  %11 = tuple ()
+  return %11 : $()
+}
+
+struct NC : ~Copyable {
+  deinit {}
+}
+
+sil hidden [ossa] [noinline] @noncopyable_arg_closure : $@convention(thin) (@guaranteed NC) -> () {
+bb0(%0 : @guaranteed $NC):
+  %retval = tuple ()
+  return %retval : $()
+}
+
+sil hidden [ossa] [noinline] @use_noncopyable_arg_closure : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> ()) -> () {
+bb0(%0 : @guaranteed $@noescape @callee_guaranteed () -> ()):
+  %2 = apply %0() : $@noescape @callee_guaranteed () -> ()
+  %3 = tuple ()
+  return %3 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @specialize_noncopyable_arg_closure : {{.*}} {
+// CHECK:           = function_ref @$s27use_noncopyable_arg_closure0b1_c1_D04main2NCVTf1c_n : $@convention(thin) (@guaranteed NC) -> ()
+// CHECK-LABEL: } // end sil function 'specialize_noncopyable_arg_closure'
+sil [ossa] @specialize_noncopyable_arg_closure : $@convention(thin) (@guaranteed NC) -> () {
+bb0(%nc : @guaranteed $NC):
+  %closure_fn = function_ref @noncopyable_arg_closure : $@convention(thin) (@guaranteed NC) -> ()
+  %closure = partial_apply [callee_guaranteed] [on_stack] %closure_fn(%nc) : $@convention(thin) (@guaranteed NC) -> ()
+  %use = function_ref @use_noncopyable_arg_closure : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> ()) -> ()
+  apply %use(%closure) : $@convention(thin) (@guaranteed @noescape @callee_guaranteed () -> ()) -> ()
+  destroy_value %closure
+  %11 = tuple ()
+  return %11 : $()
+}
+
+sil hidden [ossa] [noinline] @use_escaping_noncopyable_arg_closure : $@convention(thin) (@guaranteed @callee_guaranteed () -> ()) -> () {
+bb0(%0 : @guaranteed $@callee_guaranteed () -> ()):
+  %2 = apply %0() : $@callee_guaranteed () -> ()
+  %3 = tuple ()
+  return %3 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @dont_specialize_noncopyable_arg_closure : {{.*}} {
+// CHECK:         [[C:%.*]] = partial_apply
+// CHECK:         apply {{%[0-9]+}}([[C]]) : $@convention(thin) (@guaranteed @callee_guaranteed () -> ()) -> ()
+// CHECK-LABEL: } // end sil function 'dont_specialize_noncopyable_arg_closure'
+sil [ossa] @dont_specialize_noncopyable_arg_closure : $@convention(thin) (@owned NC) -> () {
+bb0(%nc : @owned $NC):
+  %closure_fn = function_ref @noncopyable_arg_closure : $@convention(thin) (@guaranteed NC) -> ()
+  %closure = partial_apply [callee_guaranteed] %closure_fn(%nc) : $@convention(thin) (@guaranteed NC) -> ()
+  %use = function_ref @use_escaping_noncopyable_arg_closure : $@convention(thin) (@guaranteed @callee_guaranteed () -> ()) -> ()
+  apply %use(%closure) : $@convention(thin) (@guaranteed @callee_guaranteed () -> ()) -> ()
+  destroy_value %closure
+  %11 = tuple ()
+  return %11 : $()
+}
diff --git a/test/SILOptimizer/closure_specialization_attrs.sil b/test/SILOptimizer/closure_specialization_attrs.sil
new file mode 100644
index 0000000000000..7d18fd013789d
--- /dev/null
+++ b/test/SILOptimizer/closure_specialization_attrs.sil
@@ -0,0 +1,86 @@
+// RUN: %target-sil-opt -enable-sil-verify-all -closure-specialization %s | %FileCheck %s
+
+import Builtin
+
+class C {}
+
+sil [ossa] @getC : $@convention(thin) () -> @owned C
+
+class Storage {}
+
+struct Val {}
+
+// Verify that the argument to the specialized take_closure is still @_eagerMove.
+
+// CHECK-LABEL: sil {{.*}}@$s12take_closure0B04main1CCTf1nc_n : {{.*}}{
+// CHECK:           {{bb[0-9]+}}({{%[^,]+}} : @_eagerMove @owned $C, {{%[^,]+}} :
+// CHECK-LABEL: } // end sil function '$s12take_closure0B04main1CCTf1nc_n'
+
+sil [ossa] [noinline] @take_closure : $@convention(thin) (@owned C, @guaranteed @noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()) -> () {
+bb0(%c : @_eagerMove @owned $C, %0 : @guaranteed $@noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()):
+  %getC = function_ref @getC : $@convention(thin) () -> @owned C
+  %c1 = apply %getC() : $@convention(thin) () -> @owned C
+  %c2 = apply %getC() : $@convention(thin) () -> @owned C
+  %3 = apply %0(%c1, %c2) : $@noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()
+  destroy_value %c2 : $C
+  destroy_value %c1 : $C
+  destroy_value %c : $C
+  %retval = tuple()
+  return %retval : $()
+}
+
+sil shared [ossa] @closure : $@convention(thin) (@guaranteed C, @guaranteed C, @guaranteed C) -> () {
+bb0(%0 : @guaranteed $C, %1 : @guaranteed $C, %2 : @guaranteed $C):
+  %15 = tuple ()
+  return %15 : $()
+}
+
+sil [ossa] @caller : $@convention(thin) (@owned C) -> () {
+bb0(%0 : @owned $C):
+  %3 = function_ref @closure : $@convention(thin) (@guaranteed C, @guaranteed C, @guaranteed C) -> ()
+  %4 = partial_apply [callee_guaranteed] [on_stack] %3(%0) : $@convention(thin) (@guaranteed C, @guaranteed C, @guaranteed C) -> ()
+  %take_closure = function_ref @take_closure : $@convention(thin) (@owned C, @guaranteed @noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()) -> ()
+  %5 = copy_value %0
+  %6 = apply %take_closure(%5, %4) : $@convention(thin) (@owned C, @guaranteed @noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()) -> ()
+  destroy_value %4
+  destroy_value %0
+  %retval = tuple()
+  return %retval : $()
+}
+
+// =============================================================================
+// rdar://105887096: do not insert a retain inside a read-only function.
+// For now, the specialization is disabled.
+//
+// TODO: A @noescape closure should never be converted to an @owned argument
+// regardless of the function attribute.
+
+// This should not be specialized until we support guaranteed arguments.
+// CHECK-NOT: @$s20takesReadOnlyClosure
+sil private [readonly] [ossa] @takesReadOnlyClosure : $@convention(thin) (@guaranteed @noescape @callee_guaranteed (Val) -> Val) -> Val {
+bb0(%2 : @guaranteed $@noescape @callee_guaranteed (Val) -> Val):
+  %46 = struct $Val ()
+  %261 = apply %2(%46) : $@noescape @callee_guaranteed (Val) -> Val
+  return %261 : $Val
+}
+
+sil private [ossa] @readOnlyClosure : $@convention(thin) (Val, @guaranteed Storage) -> Val {
+bb0(%0 : $Val, %1 : @closureCapture @guaranteed $Storage):
+  %46 = struct $Val ()
+  return %46 : $Val
+}
+
+// CHECK-LABEL: sil [ossa] @testPassReadOnlyClosure : $@convention(method) (@guaranteed Storage) -> Val {
+// CHECK-NOT: @owned Storage
+// CHECK: apply %{{.*}} : $@convention(thin) (@guaranteed @noescape @callee_guaranteed (Val) -> Val) -> Val
+// CHECK-LABEL: } // end sil function 'testPassReadOnlyClosure'
+sil [ossa] @testPassReadOnlyClosure : $@convention(method) (@guaranteed Storage) -> Val {
+bb0(%0 : @guaranteed $Storage):
+  %176 = function_ref @readOnlyClosure : $@convention(thin) (Val, @guaranteed Storage) -> Val
+  %177 = partial_apply [callee_guaranteed] [on_stack] %176(%0) : $@convention(thin) (Val, @guaranteed Storage) -> Val
+  %178 = mark_dependence %177 : $@noescape @callee_guaranteed (Val) -> Val on %0 : $Storage
+  %188 = function_ref @takesReadOnlyClosure : $@convention(thin) (@guaranteed @noescape @callee_guaranteed (Val) -> Val) -> Val
+  %189 = apply %188(%178) : $@convention(thin) (@guaranteed @noescape @callee_guaranteed (Val) -> Val) -> Val
+  destroy_value %178
+  return %189 : $Val
+}
diff --git a/test/SILOptimizer/closure_specialization_consolidated.sil b/test/SILOptimizer/closure_specialization_consolidated.sil
new file mode 100644
index 0000000000000..bbc1af7e09b57
--- /dev/null
+++ b/test/SILOptimizer/closure_specialization_consolidated.sil
@@ -0,0 +1,692 @@
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all -closure-specialization %s | %FileCheck %s
+
+import Builtin
+import Swift
+
+///////////////////
+// Utility Types //
+///////////////////
+
+protocol P {
+  func foo(f: (Int32)->Int32, _ j: Int32) -> Int32
+}
+
+protocol Q {
+}
+
+public class C {
+  @_hasStorage var c: C? { get set }
+  init()
+}
+
+public struct S: Q {
+  @_hasStorage var c: C? { get set }
+  init(c: C?)
+  init()
+}
+
+// = Test Summary =
+// We test the following things here:
+//
+// 1. Address Argument
+// 2. ThinToThick, Partial Apply:
+//   a. with and without removal of closure.
+//   b. @owned and @guaranteed.
+// 3. Bad NonFailureExitBB.
+// 4. No Call in Apply Callee.
+// 5. Non simple closure (i.e. non function_ref closure).
+// 6. Handle interface return types correctly.
+
+////////////////////////////
+// Address Argument Tests //
+////////////////////////////
+//
+// Make sure that we can specialize even if we have address arguments.
+//
+// But we don't handle closures that close over address types passed as @in or
+// @in_guaranteed.
+// (*NOTE* this includes address and non-address only types).
+// This is a temporary limitation.
+// CHECK-LABEL: sil [ossa] @address_closure : $@convention(thin) (@in Int32) -> () {
+sil [ossa] @address_closure : $@convention(thin) (@in Int32) -> () {
+bb0(%0 : $*Int32):
+  %6 = tuple()
+  return %6 : $()
+}
+
+sil [ossa] @address_closure_struct_complex : $@convention(thin) (@in_guaranteed S) -> () {
+bb0(%0 : $*S):
+  %6 = tuple()
+  return %6 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
+sil [ossa] @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
+bb0(%0 : @owned $@callee_owned () -> ()):
+  %1 = apply %0() : $@callee_owned () -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// Check that a specialization of address_closure_noescape_user was generated which does not
+// take a closure as a parameter anymore.
+// CHECK-LABEL: sil shared [ossa] @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
+// CHECK: function_ref @address_closure_trivial : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
+// CHECK: partial_apply %{{.*}} : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
+// CHECK: apply
+// CHECK: return
+
+// Check that a specialization of address_closure_noescape_user was generated which does not
+// take a closure as a parameter anymore.
+// CHECK-LABEL: sil shared [ossa] @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable Int32) -> ()
+// CHECK: function_ref @address_closure_trivial_mutating : $@convention(thin) (@inout_aliasable Int32) -> ()
+// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable Int32) -> ()
+// CHECK: apply
+// CHECK: return
+
+// Check that a specialization of address_closure_noescape_user was generated which does not
+// take a closure as a parameter anymore.
+// CHECK-LABEL: sil shared [ossa] @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable any P) -> ()
+// CHECK: function_ref @address_closure_existential : $@convention(thin) (@inout_aliasable any P) -> ()
+// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable any P) -> ()
+// CHECK: apply
+// CHECK: return
+
+// Check that a specialization of address_closure_noescape_user was generated which does not
+// take a closure as a parameter anymore.
+// CHECK-LABEL: sil shared [ossa] @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+// CHECK: function_ref @address_closure_struct1 : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+// CHECK: apply
+// CHECK: return
+
+// Check that a specialization of address_closure_user was generated which does not
+// take a closure as a parameter anymore.
+// CHECK-LABEL: sil shared [ossa] @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+// CHECK: function_ref @address_closure_struct2 : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+// CHECK: apply
+// CHECK: return
+
+// Check that a specialization of address_closure_user was generated which does not
+// take a closure as a parameter anymore.
+// CHECK-LABEL: sil shared [ossa] @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
+// CHECK: function_ref @address_closure_class1 : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
+// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
+// CHECK: apply
+// CHECK: return
+
+// CHECK-LABEL: sil [ossa] @address_closure_noescape_user : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> () {
+sil [ossa] @address_closure_noescape_user : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> () {
+bb0(%0 : @owned $@noescape @callee_owned () -> ()):
+  %1 = apply %0() : $@noescape @callee_owned () -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @address_caller : $@convention(thin) (@in Int32) -> () {
+// CHECK-NOT: _TTSf1cl15address_closureSi__address_closure_user
+sil [ossa] @address_caller : $@convention(thin) (@in Int32) -> () {
+bb0(%0 : $*Int32):
+  %1 = function_ref @address_closure : $@convention(thin) (@in Int32) -> ()
+  %2 = partial_apply %1(%0) : $@convention(thin) (@in Int32) -> ()
+  %3 = function_ref @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  %4 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// We don't handle closures that close over address types passed as @in or
+// @in_guaranteed.
+// (*NOTE* this includes address and non-address only types).
+// This is a temporary limitation.
+//
+// CHECK-LABEL: sil [ossa] @address_caller_complex : $@convention(thin) (@in Int32) -> ()
+// CHECK-NOT: function_ref @{{.*}}address_closure_user{{.*}} : $@convention(thin) (@in Int32) -> ()
+// CHECK: partial_apply
+// CHECK-NOT: function_ref @{{.*}}address_closure_user{{.*}} : $@convention(thin) (@in Int32) -> ()
+// CHECK: return
+sil [ossa] @address_caller_complex : $@convention(thin) (@in Int32) -> () {
+bb0(%0 : $*Int32):
+  %00 = alloc_stack $Int32
+  %01 = load [trivial] %0 : $*Int32
+  store %01 to [trivial] %00 : $*Int32
+  %1 = function_ref @address_closure : $@convention(thin) (@in Int32) -> ()
+  %2 = partial_apply %1(%00) : $@convention(thin) (@in Int32) -> ()
+  %3 = function_ref @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  %2c = copy_value %2
+  %4 = apply %3(%2c) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  dealloc_stack %00 : $*Int32
+  br bb1
+
+bb1:
+  %6 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// We don't handle closures that close over address types passed as @in or
+// @in_guaranteed.
+// (*NOTE* this includes address and non-address only types).
+// This is a temporary limitation.
+//
+// CHECK-LABEL: sil [ossa] @address_caller_struct_complex : $@convention(thin) (@in S) -> ()
+// CHECK-NOT:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_user{{.*}} : $@convention(thin) (@in S) -> ()
+// CHECK: partial_apply 
+// CHECK-NOT:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_user{{.*}} : $@convention(thin) (@in S) -> ()
+// CHECK: return
+sil [ossa] @address_caller_struct_complex : $@convention(thin) (@in S) -> () {
+bb0(%0 : $*S):
+  %00 = alloc_stack $S
+  %01 = load [take] %0 : $*S
+  store %01 to [init] %00 : $*S
+  %1 = function_ref @address_closure_struct_complex : $@convention(thin) (@in_guaranteed S) -> ()
+  %2 = partial_apply %1(%00) : $@convention(thin) (@in_guaranteed S) -> ()
+  %3 = function_ref @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  %2c = copy_value %2
+  %4 = apply %3(%2c) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  dealloc_stack %00 : $*S
+  br bb1
+
+bb1:
+  %6 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// More complex tests involving address arguments.
+
+sil [ossa] @address_closure_trivial : $@convention(thin) (Int32, @inout_aliasable Int32) -> () {
+bb0(%0 : $Int32, %1 : $*Int32):
+  %9 = integer_literal $Builtin.Int32, 42
+  %10 = struct $Int32 (%9 : $Builtin.Int32)
+  store %10 to [trivial] %1 : $*Int32
+  %12 = tuple ()
+  return %12 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @address_caller_trivial
+// CHECK-NOT: partial_apply
+// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
+// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
+// CHECK-NOT: partial_apply
+// CHECK: return
+sil [ossa] @address_caller_trivial: $@convention(thin) (Int32) -> Int32 {
+bb0(%0 : $Int32):
+  %2 = alloc_stack $Int32, var, name "xx"
+  store %0 to [trivial] %2 : $*Int32
+  // function_ref address_closure_noescape_user(f:)
+  %4 = function_ref @address_closure_noescape_user : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  // function_ref address_closure_trivial(x:)
+  %5 = function_ref @address_closure_trivial : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
+  %6 = partial_apply %5(%0, %2) : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
+  %6b = convert_escape_to_noescape %6 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+  %7 = apply %4(%6b) : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  destroy_value %6
+  %8 = load [trivial] %2 : $*Int32
+  dealloc_stack %2 : $*Int32
+  return %8 : $Int32
+}
+
+sil [ossa] @address_closure_trivial_mutating : $@convention(thin) (@inout_aliasable Int32) -> () {
+bb0(%0 : $*Int32):
+  %2 = struct_element_addr %0 : $*Int32, #Int32._value
+  %3 = load [trivial] %2 : $*Builtin.Int32
+  %4 = integer_literal $Builtin.Int32, 1
+  %5 = integer_literal $Builtin.Int1, -1
+  %6 = builtin "sadd_with_overflow_Int32"(%3 : $Builtin.Int32, %4 : $Builtin.Int32, %5 : $Builtin.Int1) : $(Builtin.Int32, Builtin.Int1)
+  %7 = tuple_extract %6 : $(Builtin.Int32, Builtin.Int1), 0
+  %8 = tuple_extract %6 : $(Builtin.Int32, Builtin.Int1), 1
+  cond_fail %8 : $Builtin.Int1
+  %10 = struct $Int32 (%7 : $Builtin.Int32)
+  store %10 to [trivial] %0 : $*Int32
+  %12 = tuple ()
+  return %12 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @address_caller_trivial_mutating
+// CHECK-NOT: partial_apply
+// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable Int32) -> ()
+// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
+// CHECK-NOT: partial_apply
+// CHECK: return
+sil [ossa] @address_caller_trivial_mutating: $@convention(thin) (Int32) -> Int32 {
+bb0(%0 : $Int32):
+  %2 = alloc_stack $Int32, var, name "xx"
+  store %0 to [trivial] %2 : $*Int32
+  %4 = function_ref @address_closure_noescape_user : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %5 = function_ref @address_closure_trivial_mutating : $@convention(thin) (@inout_aliasable Int32) -> ()
+  %6 = partial_apply %5(%2) : $@convention(thin) (@inout_aliasable Int32) -> ()
+  %6b = convert_escape_to_noescape %6 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+  %7 = apply %4(%6b) : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  destroy_value %6
+  %8 = load [trivial] %2 : $*Int32
+  dealloc_stack %2 : $*Int32
+  return %8 : $Int32
+}
+
+sil [ossa] @S_init : $@convention(method) (@thin S.Type) -> @owned S
+
+sil hidden [ossa] @address_closure_body_out_result : $@convention(thin) (@in Q, @in Q) -> @out Q {
+bb0(%0 : $*Q, %1 : $*Q, %2 : $*Q):
+  %5 = init_existential_addr %0 : $*Q, $S
+  // function_ref S.init()
+  %6 = function_ref @S_init : $@convention(method) (@thin S.Type) -> @owned S
+  %7 = metatype $@thin S.Type
+  %8 = apply %6(%7) : $@convention(method) (@thin S.Type) -> @owned S
+  store %8 to [init] %5 : $*S
+  destroy_addr %2 : $*Q
+  destroy_addr %1 : $*Q
+  %12 = tuple ()
+  return %12 : $()
+}
+
+sil [ossa] @address_closure_out_result : $@convention(thin) (@in Q, @inout_aliasable Q, @inout_aliasable Q) -> @out Q {
+bb0(%0 : $*Q, %1 : $*Q, %2 : $*Q, %3 : $*Q):
+  %7 = function_ref @address_closure_body_out_result : $@convention(thin) (@in Q, @in Q) -> @out Q
+  %8 = alloc_stack $Q
+  copy_addr %2 to [init] %8 : $*Q
+  %10 = alloc_stack $Q
+  copy_addr %3 to [init] %10 : $*Q
+  %12 = apply %7(%0, %8, %10) : $@convention(thin) (@in Q, @in Q) -> @out Q
+  dealloc_stack %10 : $*Q
+  dealloc_stack %8 : $*Q
+  destroy_addr %1 : $*Q
+  %16 = tuple ()
+  return %16 : $()
+}
+
+// Check that a specialization of address_closure_user_out_result was generated which does not
+// take a closure as a parameter anymore.
+// CHECK-LABEL: sil shared [ossa] @{{.*}}address_closure_user_out_result{{.*}} : $@convention(thin) (@inout_aliasable any Q, @inout_aliasable any Q) -> @out any Q
+// CHECK: function_ref @address_closure_out_result : $@convention(thin) (@in any Q, @inout_aliasable any Q, @inout_aliasable any Q) -> @out any Q
+// CHECK: [[PARTIAL_APPLY:%.*]] = partial_apply %{{.*}} : $@convention(thin) (@in any Q, @inout_aliasable any Q, @inout_aliasable any Q) -> @out any Q
+// CHECK: apply [[PARTIAL_APPLY]]
+// CHECK: return
+
+sil [ossa] @address_closure_user_out_result : $@convention(thin) (@owned @noescape @callee_owned (@in Q) -> @out Q) -> @out Q {
+bb0(%0 : $*Q, %1 : @owned $@noescape @callee_owned (@in Q) -> @out Q):
+  %4 = alloc_stack $Q
+  %5 = init_existential_addr %4 : $*Q, $S
+  %6 = function_ref @S_init : $@convention(method) (@thin S.Type) -> @owned S
+  %7 = metatype $@thin S.Type
+  %8 = apply %6(%7) : $@convention(method) (@thin S.Type) -> @owned S
+  store %8 to [init] %5 : $*S
+  %10 = apply %1(%0, %4) : $@noescape @callee_owned (@in Q) -> @out Q
+  dealloc_stack %4 : $*Q
+  %13 = tuple ()
+  return %13 : $()
+}
+
+// Check that closure specialization can handle cases where the full closure type may have
+// unsupported address type arguments (e.g. @in or @out), but the partial_apply has only
+// supported address type arguments, i.e. @inout or @inout_aliasable.
+//
+// CHECK-LABEL: sil [ossa] @address_caller_out_result : $@convention(thin) (@in any Q, @in any Q) -> @out any Q
+// CHECK-NOT: partial_apply
+// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_user_out_result{{.*}} : $@convention(thin) (@inout_aliasable any Q, @inout_aliasable any Q) -> @out any Q
+// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
+// CHECK-NOT: partial_apply
+// CHECK: return
+sil [ossa] @address_caller_out_result: $@convention(thin) (@in Q, @in Q) -> @out Q {
+bb0(%0 : $*Q, %1 : $*Q, %2 : $*Q):
+  %5 = function_ref @address_closure_user_out_result : $@convention(thin) (@owned @noescape @callee_owned (@in Q) -> @out Q) -> @out Q
+  %6 = function_ref @address_closure_out_result : $@convention(thin) (@in Q, @inout_aliasable Q, @inout_aliasable Q) -> @out Q
+  %7 = partial_apply %6(%1, %2) : $@convention(thin) (@in Q, @inout_aliasable Q, @inout_aliasable Q) -> @out Q 
+  %7b = convert_escape_to_noescape %7 : $@callee_owned (@in Q) -> @out Q to $@noescape @callee_owned (@in Q) -> @out Q
+  %8 = apply %5(%0, %7b) : $@convention(thin) (@owned @noescape @callee_owned (@in Q) -> @out Q) -> @out Q
+  destroy_value %7
+  destroy_addr %2 : $*Q
+  destroy_addr %1 : $*Q
+  %11 = tuple ()
+  return %11 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @address_caller_existential
+// CHECK-NOT: partial_apply
+// CHECK:  [[SPECIALIZED_FN2:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable any P) -> ()
+// CHECK: apply [[SPECIALIZED_FN2]]{{.*}}
+// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable any P) -> ()
+// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
+// CHECK-NOT: partial_apply
+// CHECK: return
+sil [ossa] @address_caller_existential : $@convention(thin) (@in P, @in P, Int32) -> @out P {
+bb0(%0 : $*P, %1 : $*P, %2 : $*P, %3 : $Int32):
+  %7 = alloc_stack $P
+  copy_addr %1 to [init] %7 : $*P
+  %9 = function_ref @address_closure_existential : $@convention(thin) (@inout_aliasable P) -> ()
+  %10 = partial_apply %9(%7) : $@convention(thin) (@inout_aliasable P) -> ()
+  %10b = convert_escape_to_noescape %10 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+  %12 = function_ref @address_closure_noescape_user : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %14 = apply %12(%10b) : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %10c = convert_escape_to_noescape %10 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+  %16 = apply %12(%10c) : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %17 = integer_literal $Builtin.Int32, 10
+  %18 = struct_extract %3 : $Int32, #Int32._value
+  %19 = builtin "cmp_slt_Int32"(%17 : $Builtin.Int32, %18 : $Builtin.Int32) : $Builtin.Int1
+  cond_br %19, bb1, bb2
+
+bb1:
+  destroy_addr %2 : $*P
+  copy_addr %1 to [init] %0 : $*P
+  destroy_addr %1 : $*P
+  destroy_value %10
+  br bb3
+
+bb2:
+  destroy_addr %1 : $*P
+  copy_addr %2 to [init] %0 : $*P
+  destroy_addr %2 : $*P
+  destroy_value %10
+  br bb3
+
+bb3:
+  destroy_addr %7 : $*P
+  dealloc_stack %7 : $*P
+  %33 = tuple ()
+  return %33 : $()
+}
+
+sil shared [ossa] @address_closure_existential : $@convention(thin) (@inout_aliasable P) -> () {
+bb0(%0 : $*P):
+  %7 = tuple ()
+  return %7 : $()
+}
+
+sil [ossa] @address_closure_struct1 : $@convention(thin) (@inout_aliasable S, @owned S) -> () {
+bb0(%0 : $*S, %1 : @owned $S):
+  %4 = struct_element_addr %0 : $*S, #S.c
+  %5 = load [copy] %4 : $*Optional<C>
+  store %1 to [assign] %0 : $*S
+  destroy_value %5
+  %8 = tuple ()
+  return %8 : $()
+}
+
+sil [ossa] @address_closure_struct2 : $@convention(thin) (@inout_aliasable S, @owned S) -> () {
+bb0(%0 : $*S, %1 : @owned $S):
+  %4 = struct_element_addr %0 : $*S, #S.c
+  %5 = load [copy] %4 : $*Optional<C>
+  store %1 to [assign] %0 : $*S
+  destroy_value %5
+  %8 = tuple ()
+  return %8 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @address_caller_struct
+// CHECK-NOT: partial_apply
+// CHECK: [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> () 
+// CHECK: apply [[SPECIALIZED_FN1]]
+// CHECK: [[SPECIALIZED_FN2:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> () 
+// CHECK: apply [[SPECIALIZED_FN2]]
+// CHECK-NOT: partial_apply
+// CHECK: return
+sil [ossa] @address_caller_struct : $@convention(thin) (@owned S, @guaranteed S) -> @owned S {
+bb0(%0 : @owned $S, %1 : @guaranteed $S):
+  %2 = copy_value %0
+  %3 = copy_value %1
+  %4 = alloc_stack $S, var, name "xx"
+  store %0 to [init] %4 : $*S
+  %7 = function_ref @address_closure_noescape_user : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %8 = function_ref @address_closure_struct1 : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+  %9 = partial_apply %8(%4, %3) : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+  %9b = convert_escape_to_noescape %9 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+  %12 = apply %7(%9b) : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %13 = function_ref @address_closure_struct2 : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+  %14 = partial_apply %13(%4, %2) : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
+  %14b = convert_escape_to_noescape %14 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+  %16 = apply %7(%14b) : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %17 = load [take] %4 : $*S
+  destroy_value %9
+  destroy_value %14
+  dealloc_stack %4 : $*S
+  return %17 : $S
+}
+
+sil shared [ossa] @address_closure_class1 : $@convention(thin) (@inout_aliasable C, @owned C) -> () {
+bb0(%0 : $*C, %1 : @owned $C):
+  %4 = load [copy] %0 : $*C
+  store %1 to [assign] %0 : $*C
+  destroy_value %4
+  %7 = tuple ()
+  return %7 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @address_caller_class1
+// CHECK-NOT: partial_apply
+// CHECK:  [[SPECIALIZED_FN2:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
+// CHECK: apply [[SPECIALIZED_FN2]]{{.*}}
+// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
+// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
+// CHECK-NOT: partial_apply
+// CHECK: return
+sil [ossa] @address_caller_class1 : $@convention(thin) (@guaranteed C, @guaranteed C) -> @owned C {
+bb0(%0 : @guaranteed $C, %1 : @guaranteed $C):
+  %2 = copy_value %0
+  %3 = copy_value %1
+  %4 = alloc_stack $C, var, name "xx"
+  store %2 to [init] %4 : $*C
+  %7 = function_ref @address_closure_class1 : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
+  %8 = partial_apply %7(%4, %3) : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
+  %8b = convert_escape_to_noescape %8 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+  %10 = function_ref @address_closure_noescape_user : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %14 = apply %10(%8b) : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %8c = convert_escape_to_noescape %8 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
+  %16 = apply %10(%8c) : $@convention(thin) (@owned @noescape @callee_owned () -> ()) -> ()
+  %17 = load [copy] %4 : $*C
+  %20 = load [take] %4 : $*C
+  destroy_value %8
+  destroy_value %20
+  dealloc_stack %4 : $*C
+  return %17 : $C
+}
+
+/////////////////////////////////////
+// Thin To Thick and Partial Apply //
+/////////////////////////////////////
+//
+// Make sure that we handle these correctly with and without removal of the
+// closure and @owned and @guaranteed.
+//
+
+// CHECK-LABEL: sil [ossa] @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+sil [ossa] @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+bb0(%0 : @unowned $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : @owned $Builtin.NativeObject, %3 : @guaranteed $Builtin.NativeObject, %4 : @unowned $Builtin.NativeObject, %5 : $Builtin.Int32, %6 : @owned $Builtin.NativeObject, %7 : @guaranteed $Builtin.NativeObject):
+  %9999 = tuple ()
+
+  destroy_value %2
+  destroy_value %6
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @small_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+sil [ossa] @small_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+bb0(%0 : @unowned $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : @owned $Builtin.NativeObject, %3 : @guaranteed $Builtin.NativeObject):
+  %9999 = tuple ()
+  destroy_value %2
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s18owned_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @owned Builtin.NativeObject) -> () {
+// CHECK: bb0
+// CHECK: [[FUN:%.*]] = function_ref @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+// CHECK: [[CLOSURE:%.*]] = partial_apply [[FUN]](
+// CHECK: [[C:%.*]] = copy_value [[CLOSURE]]
+// CHECK: apply [[C]](
+
+// CHECK-LABEL: sil shared [ossa] @$s18owned_apply_callee014small_closure_C0Tf1cnnnn_n : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+// CHECK: bb0
+// CHECK: [[FUN:%.*]] = function_ref @small_closure_callee
+// CHECK: [[CLOSURE:%.*]] = thin_to_thick_function [[FUN]] : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () to $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+// CHECK: apply [[CLOSURE]](
+
+// CHECK-LABEL: sil [ossa] @owned_apply_callee : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+sil [ossa] @owned_apply_callee : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+bb0(%0 : @owned $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), %1 : @unowned $Builtin.NativeObject, %2 : $Builtin.Int32, %3 : @owned $Builtin.NativeObject, %4 : @guaranteed $Builtin.NativeObject):
+  %5 = copy_value %3
+  apply %0(%1, %2, %5, %4) : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  destroy_value %3
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s23guaranteed_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @owned Builtin.NativeObject) -> () {
+// CHECK: bb0(%0 : @unowned $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : @owned $Builtin.NativeObject, %3 : @guaranteed $Builtin.NativeObject, %4 : @owned $Builtin.NativeObject, %5 : $Builtin.Int32, %6 : @owned $Builtin.NativeObject, %7 : @owned $Builtin.NativeObject):
+// CHECK: [[FUN:%.*]] = function_ref @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+// CHECK: [[CLOSURE:%.*]] = partial_apply [[FUN]](
+// CHECK: [[C:%.*]] = copy_value [[CLOSURE]]
+// CHECK: apply [[C]](
+// CHECK: destroy_value [[CLOSURE]]
+
+// CHECK-LABEL: sil shared [ossa] @$s23guaranteed_apply_callee014small_closure_C0Tf1cnnnn_n : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+// CHECK: bb0(%0 : @unowned $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : @owned $Builtin.NativeObject, %3 : @guaranteed $Builtin.NativeObject):
+// CHECK: [[FUN:%.*]] = function_ref @small_closure_callee
+// CHECK: [[CLOSURE:%.*]] = thin_to_thick_function [[FUN]] :
+// CHECK: [[C:%.*]] = copy_value [[CLOSURE]]
+// CHECK: apply [[C]](
+
+// CHECK-LABEL: sil [ossa] @guaranteed_apply_callee : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+sil [ossa] @guaranteed_apply_callee : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+bb0(%0 : @guaranteed $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), %1 : @unowned $Builtin.NativeObject, %2 : $Builtin.Int32, %3 : @owned $Builtin.NativeObject, %4 : @guaranteed $Builtin.NativeObject):
+  %5 = copy_value %3
+  %6 = copy_value %0
+  apply %6(%1, %2, %5, %4) : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  destroy_value %3
+  %9999 = tuple ()
+  return %9999 : $()
+}
+sil [ossa] @guaranteed_apply_callee_throw : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Error) -> @error Error {
+bb0(%0 : @guaranteed $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), %1 : @unowned $Builtin.NativeObject, %2 : $Builtin.Int32, %3 : @owned $Builtin.NativeObject, %4 : @guaranteed $Builtin.NativeObject, %5: @owned $Error):
+  %6 = copy_value %3
+  %7 = copy_value %0
+  apply %7(%1, %2, %6, %4) : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  destroy_value %3
+  throw %5 : $Error
+}
+
+// CHECK-LABEL: sil [ossa] @thin_thick_and_partial_apply_test : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned any Error) -> () {
+// CHECK: bb0([[ARG0:%.*]] : @unowned $Builtin.NativeObject, [[ARG1:%.*]] : $Builtin.Int32, [[ARG2:%.*]] : @owned $Builtin.NativeObject, [[ARG3:%.*]] : @guaranteed $Builtin.NativeObject, [[ARG4:%.*]] : @owned $any Error):
+// CHECK: [[OLD_CLOSURE_CALLEE1:%.*]] = function_ref @large_closure_callee
+// CHECK: [[OLD_CLOSURE_CALLEE2:%.*]] = function_ref @small_closure_callee
+// CHECK: [[C0:%.*]] = copy_value [[ARG0]]
+// CHECK-NEXT: [[C2:%.*]] = copy_value [[ARG2]]
+// CHECK-NEXT: [[C3:%.*]] = copy_value [[ARG3]]
+// CHECK: [[D0:%.*]] = copy_value [[C0]]
+// CHECK-NEXT: [[D2:%.*]] = copy_value [[C2]]
+// CHECK-NEXT: [[D3:%.*]] = copy_value [[C3]]
+// CHECK: [[E0:%.*]] = copy_value [[C0]]
+// CHECK-NEXT: [[E2:%.*]] = copy_value [[C2]]
+// CHECK-NEXT: [[E3:%.*]] = copy_value [[C3]]
+// CHECK-NOT: partial_apply [[OLD_CLOSURE_CALLEE1]]
+// CHECK-NOT: thin_to_thick_function [[OLD_CLOSURE_CALLEE2]]
+// CHECK: [[SPECFUN1:%.*]] = function_ref @$s18owned_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n
+// CHECK: apply [[SPECFUN1]](
+// CHECK: [[SPECFUN3:%.*]] = function_ref @$s18owned_apply_callee014small_closure_C0Tf1cnnnn_n
+// CHECK: apply [[SPECFUN3]](
+// CHECK: [[SPECFUN0:%.*]] = function_ref @$s23guaranteed_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n
+// CHECK: apply [[SPECFUN0]](
+// CHECK: [[SPECFUN2:%.*]] = function_ref @$s23guaranteed_apply_callee014small_closure_C0Tf1cnnnn_n
+// CHECK: apply [[SPECFUN2]](
+// CHECK-NEXT: destroy_value [[C0]]
+// CHECK-NEXT: destroy_value [[C2]]
+// CHECK-NEXT: destroy_value [[C3]]
+// CHECK: [[SPECFUN4:%.*]] = function_ref @$s29guaranteed_apply_callee_throw014small_closure_C0Tf1cnnnnn_n
+// CHECK-NEXT: try_apply [[SPECFUN4]](
+sil [ossa] @thin_thick_and_partial_apply_test : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Error) -> () {
+bb0(%0 : @unowned $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : @owned $Builtin.NativeObject, %3 : @guaranteed $Builtin.NativeObject, %11: @owned $Error):
+  %4 = function_ref @owned_apply_callee : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  %5 = function_ref @guaranteed_apply_callee : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  %6 = function_ref @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  %7 = function_ref @small_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  %10 = function_ref @guaranteed_apply_callee_throw : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Error) -> @error Error
+
+  %0c = copy_value %0
+  %2c = copy_value %2
+  %3c = copy_value %3
+  %8 = partial_apply %6(%0c, %1, %2c, %3c) : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  %9 = thin_to_thick_function %7 : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () to $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+
+  %2d = copy_value %2
+  %8c = copy_value %8
+  apply %4(%8c, %0, %1, %2d, %3) : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  %2e = copy_value %2
+  apply %4(%9, %0, %1, %2e, %3) : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  %2f = copy_value %2
+  apply %5(%8, %0, %1, %2f, %3) : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+  %2g = copy_value %2
+  apply %5(%9, %0, %1, %2g, %3) : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
+
+  destroy_value %8
+  try_apply %10(%9, %0, %1, %2, %3, %11) : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Error) -> @error Error, normal bb2, error bb3
+
+bb2(%n : $()):
+  br bb4
+
+bb3(%e : $Error):
+  br bb4
+
+bb4:
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+//////////////////////////////
+// Non Function Ref Closure //
+//////////////////////////////
+//
+// Make sure we do not try to specialize a closure if we are not closing over a
+// direct function ref.
+
+// CHECK-LABEL: @$s4test3barSiAA1P_p_SitF : $@convention(thin) (@in any P, Int32) -> Int32 {
+// CHECK: partial_apply
+// CHECK: apply
+sil [noinline] [ossa] @$s4test3barSiAA1P_p_SitF : $@convention(thin) (@in P, Int32) -> Int32 {
+bb0(%0 : $*P, %1 : $Int32):
+  %2 = open_existential_addr mutable_access %0 : $*P to $*@opened("01234567-89ab-cdef-0123-000000000000", P) Self
+  %3 = witness_method $@opened("01234567-89ab-cdef-0123-000000000000", P) Self, #P.foo, %2 : $*@opened("01234567-89ab-cdef-0123-000000000000", P) Self : $@convention(witness_method: P) @callee_owned <T: P> (@callee_owned (Int32) -> Int32, Int32, @inout T) -> Int32
+  %4 = integer_literal $Builtin.Int32, 2
+  %5 = struct $Int32 (%4 : $Builtin.Int32)
+  // function_ref test.baz (Swift.Int32)(m : Swift.Int32) -> Swift.Int32
+  %6 = function_ref @$s4test3bazSiSi1m_tcSiF : $@convention(thin) (Int32, Int32) -> Int32
+  %7 = partial_apply %6(%5) : $@convention(thin) (Int32, Int32) -> Int32
+  %8 = apply %3<@opened("01234567-89ab-cdef-0123-000000000000", P) Self>(%7, %1, %2) : $@convention(witness_method: P) @callee_owned <T: P> (@callee_owned (Int32) -> Int32, Int32, @inout T) -> Int32
+  destroy_value %7
+  destroy_addr %0 : $*P
+  return %8 : $Int32
+}
+
+sil [ossa] @$s4test3bazSiSi1m_tcSiF : $@convention(thin) (Int32, Int32) -> Int32
+
+//////////////////////////////////////////////////////////////////////////////////
+// Make sure that we properly set a specialized closure's indirect return type. //
+//////////////////////////////////////////////////////////////////////////////////
+//
+// SIL verification should catch the incorrect type.
+// rdar:://19321284
+
+// CHECK-LABEL: sil [serialized] [ossa] @callee : $@convention(thin) (Builtin.Int32) -> () {
+sil [serialized] [ossa] @callee : $@convention(thin) (Builtin.Int32) -> () {
+bb0(%0 : $Builtin.Int32):
+  unreachable
+}
+
+sil shared [serialized] [ossa] @thunk : $@convention(thin) (@owned @callee_owned () -> ()) -> @out () {
+bb0(%0 : $*(), %1 : @owned $@callee_owned () -> ()):
+  apply %1() : $@callee_owned () -> ()
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: @test_closure_propagation : $@convention(thin) () -> () {
+// CHECK-NOT: partial_apply
+sil [serialized] [ossa] @test_closure_propagation : $@convention(thin) () -> () {
+bb0:
+  %f1 = function_ref @callee : $@convention(thin) (Builtin.Int32) -> ()
+  %i1 = integer_literal $Builtin.Int32, 24
+  %p1 = partial_apply %f1(%i1) : $@convention(thin) (Builtin.Int32) -> ()
+  %f2 = function_ref @thunk : $@convention(thin) (@owned @callee_owned () -> ()) -> @out ()
+  %s1 = alloc_stack $()
+  %a1 = apply %f2(%s1, %p1) : $@convention(thin) (@owned @callee_owned () -> ()) -> @out ()
+  dealloc_stack %s1 : $*()
+  unreachable
+}
diff --git a/test/SILOptimizer/closure_specialization_fragile.sil b/test/SILOptimizer/closure_specialization_fragile.sil
new file mode 100644
index 0000000000000..72c67f758bf03
--- /dev/null
+++ b/test/SILOptimizer/closure_specialization_fragile.sil
@@ -0,0 +1,60 @@
+// RUN: %target-sil-opt  %s -verify -closure-specialization -o -  | %FileCheck %s
+
+// Make sure we do not specialize resilientCallee.
+
+sil_stage canonical
+
+import Builtin
+import Swift
+import SwiftShims
+
+@_optimize(none) public func action()
+
+@inline(__always) public func fragileCaller()
+
+public func resilientCallee(fn: () -> ())
+
+// action()
+sil [Onone] [ossa] @$s26closure_specialize_fragile6actionyyF : $@convention(thin) () -> () {
+bb0:
+  %0 = tuple ()
+  return %0 : $()
+} // end sil function '$s26closure_specialize_fragile6actionyyF'
+
+// CHECK-LABEL: sil [serialized] [heuristic_always_inline] [ossa] @$s26closure_specialize_fragile0C6CalleryyF : $@convention(thin) () -> ()
+// CHECK: function_ref @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+// CHECK: return
+// fragileCaller()
+sil [serialized] [heuristic_always_inline] [ossa] @$s26closure_specialize_fragile0C6CalleryyF : $@convention(thin) () -> () {
+bb0:
+  // function_ref resilientCallee(fn:)
+  %0 = function_ref @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  // function_ref closure #1 in fragileCaller()
+  %1 = function_ref @$s26closure_specialize_fragile0C6CalleryyFyycfU_ : $@convention(thin) () -> () 
+  %2 = thin_to_thick_function %1 : $@convention(thin) () -> () to $@callee_owned () -> () 
+  %3 = apply %0(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+  %4 = tuple ()
+  return %4 : $()
+} // end sil function '$s26closure_specialize_fragile0C6CalleryyF'
+
+// CHECK-LABEL: sil [ossa] @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+
+// resilientCallee(fn:)
+sil [ossa] @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
+bb0(%0 : @owned $@callee_owned () -> ()):
+  %1 = copy_value %0
+  %3 = apply %1() : $@callee_owned () -> ()
+  destroy_value %0
+  %5 = tuple ()
+  return %5 : $()
+} // end sil function '$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF'
+
+// closure #1 in fragileCaller()
+sil shared [serialized] [ossa] @$s26closure_specialize_fragile0C6CalleryyFyycfU_ : $@convention(thin) () -> () {
+bb0:
+  // function_ref action()
+  %0 = function_ref @$s26closure_specialize_fragile6actionyyF : $@convention(thin) () -> () 
+  %1 = apply %0() : $@convention(thin) () -> ()
+  %2 = tuple ()
+  return %2 : $()
+} // end sil function '$s26closure_specialize_fragile0C6CalleryyFyycfU_'
diff --git a/test/SILOptimizer/closure_specialization_opaque.sil b/test/SILOptimizer/closure_specialization_opaque.sil
new file mode 100644
index 0000000000000..c788b76a27b39
--- /dev/null
+++ b/test/SILOptimizer/closure_specialization_opaque.sil
@@ -0,0 +1,41 @@
+// RUN: %target-sil-opt -sil-print-types -enable-sil-opaque-values -enable-sil-verify-all -closure-specialization %s | %FileCheck %s
+
+struct TestView {}
+struct TestRange {}
+struct TestSlice {}
+
+// helper
+sil [ossa] @closure : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> () {
+bb0(%0 : $*TestView, %1 : $TestRange, %2 : $TestSlice):
+  %1284 = tuple ()
+  return %1284 : $()
+}
+
+// helper
+sil [ossa] @thunk : $@convention(thin) (@inout TestView, @owned @callee_owned (@inout TestView) -> ()) -> () {
+bb0(%0 : $*TestView, %1 : @owned $@callee_owned (@inout TestView) ->()):
+  %call = apply %1(%0) : $@callee_owned (@inout TestView) -> ()
+  %1284 = tuple ()
+  return %1284 : $()
+}
+
+// Test that ClosureSpecializer can handle captured @in args, in addition to direct args.
+//
+// CHECK-LABEL: sil [ossa] @testSpecializeThunk : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> () {
+// CHECK: bb0(%0 : $*TestView, %1 : $TestRange, %2 : $TestSlice):
+// CHECK:   [[CLOSURE:%.*]] = function_ref @closure : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> ()
+// CHECK:   [[THUNK:%.*]] = function_ref @thunk : $@convention(thin) (@inout TestView, @owned @callee_owned (@inout TestView) -> ()) -> ()
+// CHECK:   [[SPECIALIZED:%.*]] = function_ref @$s5thunk7closure4main9TestRangeVAC0D5SliceVTf1nc_n : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> ()
+// CHECK:   [[CALL:%.*]] = apply [[SPECIALIZED]](%0, %1, %2) : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> ()
+// CHECK:   %{{.*}} = tuple ()
+// CHECK:   return %{{.*}} : $()
+// CHECK-LABEL: } // end sil function 'testSpecializeThunk'
+sil [ossa] @testSpecializeThunk : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> () {
+bb0(%0 : $*TestView, %1 : $TestRange, %2 : $TestSlice):
+  %closurefn = function_ref @closure : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> ()
+  %pa = partial_apply %closurefn(%1, %2) : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> ()
+  %thunk = function_ref @thunk : $@convention(thin) (@inout TestView, @owned @callee_owned (@inout TestView) -> ()) -> ()
+  %call = apply %thunk(%0, %pa) : $@convention(thin) (@inout TestView, @owned @callee_owned (@inout TestView) -> ()) -> ()
+  %1284 = tuple ()
+  return %1284 : $()
+}
diff --git a/test/SILOptimizer/closure_specialization_simple.sil b/test/SILOptimizer/closure_specialization_simple.sil
new file mode 100644
index 0000000000000..d969a39d0017a
--- /dev/null
+++ b/test/SILOptimizer/closure_specialization_simple.sil
@@ -0,0 +1,387 @@
+// RUN: %target-sil-opt -enable-sil-verify-all -closure-specialization %s | %FileCheck %s
+
+import Builtin
+import Swift
+
+sil @simple_partial_apply_fun : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+
+// CHECK-LABEL: sil shared [ossa] @$s27simple_partial_apply_caller0a1_b1_C4_funBi1_Tf1c_n : $@convention(thin) (Builtin.Int1) -> Builtin.Int1 {
+// CHECK: bb0([[CAPTURED_ARG:%.*]] : $Builtin.Int1):
+// CHECK: [[CLOSED_OVER_FUN:%.*]] = function_ref @simple_partial_apply_fun :
+// CHECK: [[NEW_PAI:%.*]] = partial_apply [[CLOSED_OVER_FUN]]
+// CHECK: destroy_value [[NEW_PAI]]
+sil [ossa] @simple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1 {
+bb0(%0 : @owned $@callee_owned (Builtin.Int1) -> Builtin.Int1):
+  br bb1
+
+bb1:
+  %1 = integer_literal $Builtin.Int1, 0
+  // We cannot do anything here for now but in the future I think we should try
+  // to handle this in closure specialization potentially.
+  %0c = copy_value %0
+  %2 = apply %0c(%1) : $@callee_owned (Builtin.Int1) -> Builtin.Int1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  return %2 : $Builtin.Int1
+}
+
+// CHECK-LABEL: sil shared [ossa] @$s37simple_partial_apply_2nd_level_caller0a1_b1_C4_funBi1_Tf1c_n : $@convention(thin) (Builtin.Int1) -> Builtin.Int1 {
+// CHECK: bb0([[CAPTURED_ARG:%.*]] : $Builtin.Int1):
+// CHECK: [[SPECIALIZED_CALLEE:%.*]] = function_ref @$s27simple_partial_apply_caller0a1_b1_C4_funBi1_Tf1c_n  :
+// CHECK: [[RET:%.*]]= apply [[SPECIALIZED_CALLEE]]([[CAPTURED_ARG]])
+// CHECK: return [[RET]]
+sil [ossa] @simple_partial_apply_2nd_level_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1 {
+bb0(%0 : @owned $@callee_owned (Builtin.Int1) -> Builtin.Int1):
+  br bb1
+
+bb1:
+  %1 = function_ref @simple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+  %0c = copy_value %0
+  %2 = apply %1(%0c) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  return %2 : $Builtin.Int1
+}
+sil @simple_partial_apply_caller_decl : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+
+// CHECK-LABEL: sil shared [ossa] @$s36simple_multiple_partial_apply_caller0a1_c1_D4_funBi1_ABBi1_Tf1cc_n : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1 {
+// CHECK:         [[C:%.*]] = function_ref @simple_partial_apply_fun : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+// CHECK:           = partial_apply [[C]](%0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+// CHECK:           = partial_apply [[C]](%1) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+// CHECK:       } // end sil function '$s36simple_multiple_partial_apply_caller0a1_c1_D4_funBi1_ABBi1_Tf1cc_n'
+
+// CHECK-LABEL: sil shared [ossa] @$s36simple_multiple_partial_apply_caller19closure_with_stringSSTf1cC0_n : $@convention(thin) (@owned String) -> Builtin.Int1 {
+// %0                                             // user: %2
+// CHECK:         %1 = function_ref @closure_with_string : $@convention(thin) (Builtin.Int1, @guaranteed String) -> Builtin.Int1
+// CHECK:         %2 = partial_apply %1(%0) : $@convention(thin) (Builtin.Int1, @guaranteed String) -> Builtin.Int1
+// CHECK:         %3 = copy_value %2
+// CHECK:         br bb1
+// CHECK:       } // end sil function '$s36simple_multiple_partial_apply_caller19closure_with_stringSSTf1cC0_n'
+sil [ossa] @simple_multiple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1, @owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1 {
+bb0(%0 : @owned $@callee_owned (Builtin.Int1) -> Builtin.Int1, %1 : @owned $@callee_owned (Builtin.Int1) -> Builtin.Int1):
+  br bb1
+
+bb1:
+  %2 = integer_literal $Builtin.Int1, 0
+  // We cannot do anything here for now but in the future I think we should try
+  // to handle this in closure specialization potentially.
+  %0c = copy_value %0
+  apply %0c(%2) : $@callee_owned (Builtin.Int1) -> Builtin.Int1
+  %1c = copy_value %1
+  apply %1c(%2) : $@callee_owned (Builtin.Int1) -> Builtin.Int1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  destroy_value %1
+  return %2 : $Builtin.Int1
+}
+
+sil @simple_partial_apply_fun2 : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+sil [ossa] @simple_partial_apply_caller2 : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1 {
+bb0(%0 : @owned $@callee_owned (Builtin.Int1) -> Builtin.Int1):
+  br bb1
+
+bb1:
+  %1 = integer_literal $Builtin.Int1, 0
+  // We cannot do anything here for now but in the future I think we should try
+  // to handle this in closure specialization potentially.
+  %0c = copy_value %0
+  %2 = apply %0c(%1) : $@callee_owned (Builtin.Int1) -> Builtin.Int1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  return %2 : $Builtin.Int1
+}
+
+
+sil @indirect_parameter_partial_apply_fun : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
+
+sil [ossa] @indirect_parameter_partial_apply_caller1 : $@convention(thin) (@owned @callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1) -> () {
+bb0(%0 : @owned $@callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1):
+  br bb1
+
+bb1:
+  %1 = alloc_stack $Builtin.Int1
+  %2 = alloc_stack $Builtin.Int1
+  %3 = alloc_stack $Builtin.Int1
+  %4 = integer_literal $Builtin.Int1, 0
+  store %4 to [trivial] %1
+  store %4 to [trivial] %2
+  %0c = copy_value %0
+  apply %0c(%3, %1, %4, %2) : $@callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
+  dealloc_stack %3
+  dealloc_stack %2
+  dealloc_stack %1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+sil [ossa] @indirect_parameter_partial_apply_caller2 : $@convention(thin) (@owned @callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1) -> () {
+bb0(%0 : @owned $@callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1):
+  br bb1
+
+bb1:
+  %1 = alloc_stack $Builtin.Int1
+  %2 = integer_literal $Builtin.Int1, 0
+  %0c = copy_value %0
+  apply %0c(%1, %1, %2) : $@callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1
+  dealloc_stack %1 : $*Builtin.Int1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+sil [ossa] @indirect_parameter_partial_apply_caller3 : $@convention(thin) (@owned @callee_owned (@in Builtin.Int1) -> @out Builtin.Int1) -> () {
+bb0(%0 : @owned $@callee_owned (@in Builtin.Int1) -> @out Builtin.Int1):
+  br bb1
+
+bb1:
+  %1 = alloc_stack $Builtin.Int1
+  %0c = copy_value %0
+  apply %0c(%1, %1) : $@callee_owned (@in Builtin.Int1) -> @out Builtin.Int1
+  dealloc_stack %1 : $*Builtin.Int1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+sil [ossa] @indirect_parameter_partial_apply_caller4 : $@convention(thin) (@owned @callee_owned () -> @out Builtin.Int1) -> () {
+bb0(%0 : @owned $@callee_owned () -> @out Builtin.Int1):
+  br bb1
+
+bb1:
+  %1 = alloc_stack $Builtin.Int1
+  %0c = copy_value %0
+  apply %0c(%1) : $@callee_owned () -> @out Builtin.Int1
+  dealloc_stack %1 : $*Builtin.Int1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+sil [ossa] @indirect_parameter_partial_apply_caller5 : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
+bb0(%0 : @owned $@callee_owned () -> ()):
+  br bb1
+
+bb1:
+  %0c = copy_value %0
+  apply %0c() : $@callee_owned () -> ()
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+sil [ossa] @indirect_parameter_partial_apply_caller6 : $@convention(thin) (@owned @callee_owned () -> @out Builtin.Int1) -> @out Builtin.Int1 {
+bb0(%1 : $*Builtin.Int1, %0 : @owned $@callee_owned () -> @out Builtin.Int1):
+  br bb1
+
+bb1:
+  %0c = copy_value %0
+  apply %0c(%1) : $@callee_owned () -> @out Builtin.Int1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+sil [ossa] @indirect_parameter_partial_apply_caller7 : $@convention(thin) (@owned @callee_owned () -> @out Builtin.Int1) -> @out (Builtin.Int1, Builtin.Int1) {
+bb0(%1 : $*(Builtin.Int1, Builtin.Int1), %0 : @owned $@callee_owned () -> @out Builtin.Int1):
+  br bb1
+
+bb1:
+  %2 = alloc_stack $Builtin.Int1
+  %3 = alloc_stack $Builtin.Int1
+  %0c = copy_value %0
+  %0d = copy_value %0
+  apply %0c(%2) : $@callee_owned () -> @out Builtin.Int1
+  apply %0d(%3) : $@callee_owned () -> @out Builtin.Int1
+  %4 = load [trivial] %2: $*Builtin.Int1
+  %5 = load [trivial] %3: $*Builtin.Int1
+  %6 = tuple(%4 : $Builtin.Int1, %5: $Builtin.Int1)
+  store %6 to [trivial] %1 : $*(Builtin.Int1, Builtin.Int1)
+  dealloc_stack %3: $*Builtin.Int1
+  dealloc_stack %2: $*Builtin.Int1
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  destroy_value %0
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @loop_driver : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> () {
+// CHECK-DAG:     [[SPECIALIZED_FUN:%.*]] = function_ref @$s27simple_partial_apply_caller0a1_b1_C4_funBi1_Tf1c_n : $@convention(thin) (Builtin.Int1) -> Builtin.Int1
+// CHECK:         apply [[SPECIALIZED_FUN]]
+// CHECK-DAG:     [[SPECIALIZED_FUN2:%.*]] = function_ref @$s37simple_partial_apply_2nd_level_caller0a1_b1_C4_funBi1_Tf1c_n : $@convention(thin) (Builtin.Int1) -> Builtin.Int1
+// CHECK:         apply [[SPECIALIZED_FUN2]]
+
+// We can't call this one b/c it is just a declaration.
+// CHECK:         [[UNSPECIALIZED_FUN_DECL:%.*]] = function_ref @simple_partial_apply_caller_decl : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+// CHECK:         apply [[UNSPECIALIZED_FUN_DECL]]
+
+// We handle closures with indirect results.
+// CHECK:         [[CLOSUREFUN:%.*]] = function_ref @indirect_parameter_partial_apply_fun
+// CHECK-NOT:     partial_apply [[CLOSUREFUN]]()
+// CHECK-NOT:     partial_apply [[CLOSUREFUN]]()
+
+// We don't handle captured indirect @in and @in_guaranteed parameters yet.
+// CHECK:         [[CLOSURE2:%.*]] = partial_apply [[CLOSUREFUN]](%{{.*}})
+// CHECK:         [[CLOSURE3:%.*]] = partial_apply [[CLOSUREFUN]](%{{.*}})
+// CHECK:         [[CLOSURE4:%.*]] = partial_apply [[CLOSUREFUN]](%{{.*}})
+
+// CHECK:         [[CALLER1:%.*]] = function_ref @indirect_parameter_partial_apply_caller1
+// CHECK:         [[CALLER2:%.*]] = function_ref @indirect_parameter_partial_apply_caller2
+// CHECK:         [[CALLER3:%.*]] = function_ref @indirect_parameter_partial_apply_caller3
+// CHECK:         [[CALLER4:%.*]] = function_ref @indirect_parameter_partial_apply_caller4
+
+// Closure with indirect result but no captured indirect parameter.
+// CHECK-NOT:     apply [[CALLER1]]
+// CHECK:         [[INLINEDCLOSURE_CALLER1:%.*]] = function_ref @$s40indirect_parameter_partial_apply_caller10a1_b1_c1_D4_funTf1c_n
+// CHECK:         apply [[INLINEDCLOSURE_CALLER1]]()
+// CHECK-NOT:     apply [[CALLER1]]
+
+// Closures with captured indirect parameters.
+// CHECK:         apply [[CALLER2]]([[CLOSURE2]])
+// CHECK:         apply [[CALLER3]]([[CLOSURE3]])
+// CHECK:         apply [[CALLER4]]([[CLOSURE4]])
+
+// CHECK:         [[SM:%.*]] = function_ref @$s36simple_multiple_partial_apply_caller0a1_c1_D4_funBi1_ABBi1_Tf1cc_n : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+// CHECK:         apply [[SM]](%0, %0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+
+// CHECK:       } // end sil function 'loop_driver'
+sil [ossa] @loop_driver : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> () {
+bb0(%0 : $Builtin.Int1, %1 : $Builtin.Int1):
+  %2 = function_ref @simple_partial_apply_fun : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+  %3 = partial_apply %2(%0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+  %4 = function_ref @simple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+  %3c = copy_value %3
+  %5 = apply %4(%3c) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+
+  %51 = function_ref @simple_partial_apply_2nd_level_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+  %52 = apply %51(%3) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+
+  %6 = partial_apply %2(%0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+  %7 = function_ref @simple_partial_apply_caller_decl : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+  %8 = apply %7(%6) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+
+  %9 = alloc_stack $Builtin.Int1
+
+  %10 = function_ref @indirect_parameter_partial_apply_fun : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
+  %11 = partial_apply %10() : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
+  %12 = partial_apply %10(%9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
+  %13 = partial_apply %10(%1, %9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
+  %14 = partial_apply %10(%9, %1, %9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
+
+  %16 = function_ref @indirect_parameter_partial_apply_caller1 : $@convention(thin) (@owned @callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1) -> ()
+  %17 = function_ref @indirect_parameter_partial_apply_caller2 : $@convention(thin) (@owned @callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1) -> ()
+  %18 = function_ref @indirect_parameter_partial_apply_caller3 : $@convention(thin) (@owned @callee_owned (@in Builtin.Int1) -> @out Builtin.Int1) -> ()
+  %19 = function_ref @indirect_parameter_partial_apply_caller4 : $@convention(thin) (@owned @callee_owned () -> @out Builtin.Int1) -> ()
+  %20 = function_ref @indirect_parameter_partial_apply_caller5 : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
+
+  apply %16(%11) : $@convention(thin) (@owned @callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1) -> ()
+  apply %17(%12) : $@convention(thin) (@owned @callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1) -> ()
+  apply %18(%13) : $@convention(thin) (@owned @callee_owned (@in Builtin.Int1) -> @out Builtin.Int1) -> ()
+  apply %19(%14) : $@convention(thin) (@owned @callee_owned () -> @out Builtin.Int1) -> ()
+
+  // Make sure we handle when we already have an out parameter correctly.
+  %21 = alloc_stack $(Builtin.Int1, Builtin.Int1)
+  %22 = function_ref @indirect_parameter_partial_apply_caller6 : $@convention(thin) (@owned @callee_owned () -> @out Builtin.Int1) -> @out Builtin.Int1
+  %23 = function_ref @indirect_parameter_partial_apply_caller7 : $@convention(thin) (@owned @callee_owned () -> @out Builtin.Int1) -> @out (Builtin.Int1, Builtin.Int1)
+  %24 = partial_apply %10(%9, %1, %9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
+  %25 = partial_apply %10(%9, %1, %9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
+  apply %22(%9, %24) : $@convention(thin) (@owned @callee_owned () -> @out Builtin.Int1) -> @out Builtin.Int1
+  apply %23(%21, %25) : $@convention(thin) (@owned @callee_owned () -> @out Builtin.Int1) -> @out (Builtin.Int1, Builtin.Int1)
+
+  dealloc_stack %21 : $*(Builtin.Int1, Builtin.Int1)
+  dealloc_stack %9 : $*Builtin.Int1
+
+  %26 = partial_apply %2(%0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+  %27 = partial_apply %2(%0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+  %28 = function_ref @simple_multiple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1, @owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+  %29 = apply %28(%26, %27) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1, @owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+
+  %30 = function_ref @simple_partial_apply_fun2 : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+  %31 = partial_apply %30(%1) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
+  %32 = function_ref @simple_partial_apply_caller2 : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+  %33 = apply %32(%31) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+
+
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+sil @closure_with_string : $@convention(thin) (Builtin.Int1, @guaranteed String) -> Builtin.Int1
+
+// CHECK-LABEL: sil [ossa] @test_multi_closure_with_string :
+// CHECK:         [[C:%.*]] = copy_value %0
+// CHECK:         [[F:%.*]] = function_ref @$s36simple_multiple_partial_apply_caller19closure_with_stringSSTf1cC0_n : $@convention(thin) (@owned String) -> Builtin.Int1
+// CHECK:           = apply [[F]]([[C]]) : $@convention(thin) (@owned String) -> Builtin.Int1
+// CHECK:       } // end sil function 'test_multi_closure_with_string'
+sil [ossa] @test_multi_closure_with_string : $@convention(thin) (@owned String) -> () {
+bb0(%0 : @owned $String):
+  %2 = function_ref @closure_with_string : $@convention(thin) (Builtin.Int1, @guaranteed String) -> Builtin.Int1
+  %26 = partial_apply %2(%0) : $@convention(thin) (Builtin.Int1, @guaranteed String) -> Builtin.Int1
+  %27 = copy_value %26
+  %28 = function_ref @simple_multiple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1, @owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+  %29 = apply %28(%26, %27) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1, @owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
+  %9999 = tuple()
+  return %9999 : $()
+}
+
diff --git a/test/SILOptimizer/closure_specialize.sil b/test/SILOptimizer/closure_specialize.sil
index b6fa0b8c0ed67..0b03a690953ee 100644
--- a/test/SILOptimizer/closure_specialize.sil
+++ b/test/SILOptimizer/closure_specialize.sil
@@ -531,9 +531,9 @@ public struct S : P {
 }
 
 // CHECK-LABEL: sil shared @$s4test1SVAA1PA2aDP3fooyS2iycFZTW8closure2SiTf1cn_n : $@convention(thin) (@thick S.Type, Int) -> Int
-sil @$s4test1SVAA1PA2aDP3fooyS2iycFZTW : $@convention(witness_method: P) (@owned @callee_owned () -> Int, @thick S.Type) -> Int {
-bb0(%0 : $@callee_owned () -> Int, %1 : $@thick S.Type):
-  %3 = apply %0() : $@callee_owned () -> Int
+sil @$s4test1SVAA1PA2aDP3fooyS2iycFZTW : $@convention(witness_method: P) (@guaranteed @noescape @callee_guaranteed () -> Int, @thick S.Type) -> Int {
+bb0(%0 : $@noescape @callee_guaranteed () -> Int, %1 : $@thick S.Type):
+  %3 = apply %0() : $@noescape @callee_guaranteed () -> Int
   return %3 : $Int
 }
 
@@ -545,10 +545,11 @@ bb0(%0 : $Int):
 sil @call_witness_method : $@convention(thin) (Int, S) -> Int {
 bb0(%0 : $Int, %1 : $S):
   %3 = function_ref @closure2 : $@convention(thin) (Int) -> Int
-  %4 = partial_apply %3(%0) : $@convention(thin) (Int) -> Int
+  %4 = partial_apply [callee_guaranteed] %3(%0) : $@convention(thin) (Int) -> Int
+  %4a = convert_escape_to_noescape %4 : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
   %5 = metatype $@thick S.Type
-  %6 = function_ref @$s4test1SVAA1PA2aDP3fooyS2iycFZTW : $@convention(witness_method: P) (@owned @callee_owned () -> Int, @thick S.Type) -> Int
-  %7 = apply %6(%4, %5) : $@convention(witness_method: P) (@owned @callee_owned () -> Int, @thick S.Type) -> Int
+  %6 = function_ref @$s4test1SVAA1PA2aDP3fooyS2iycFZTW : $@convention(witness_method: P) (@guaranteed @noescape @callee_guaranteed () -> Int, @thick S.Type) -> Int
+  %7 = apply %6(%4a, %5) : $@convention(witness_method: P) (@guaranteed @noescape @callee_guaranteed () -> Int, @thick S.Type) -> Int
   return %7 : $Int
 }
 
diff --git a/test/SILOptimizer/closure_specialize_and_cfg.sil b/test/SILOptimizer/closure_specialize_and_cfg.sil
deleted file mode 100644
index 57ea03a553085..0000000000000
--- a/test/SILOptimizer/closure_specialize_and_cfg.sil
+++ /dev/null
@@ -1,49 +0,0 @@
-// RUN: %target-sil-opt -sil-verify-without-invalidation -enable-sil-verify-all -simplify-cfg -closure-specialize %s
-
-// Test if the ClosureSpecializer correctly invalidates the dominator tree
-// even if there are no functions specialized.
-// The test just checks if the compiler does not crash.
-// First running SimplifyCFG creates the dominator tree, which should then be
-// invalidated by the ClosureSpecializer.
-// If this is not done correctly the verification will complain that the
-// dominator tree is not up to date.
-
-import Builtin
-import Swift
-
-sil @closure : $@convention(thin) () -> ()
-
-sil @use_closure : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-
-sil hidden [noinline] @use_closure2 : $@convention(thin) (@owned @callee_owned () -> (), @owned @callee_owned () -> ()) -> () {
-bb0(%0 : $@callee_owned () -> (), %1 : $@callee_owned () -> ()):
-  %2 = apply %0() : $@callee_owned () -> ()
-  %3 = apply %1() : $@callee_owned () -> ()
-  %4 = tuple ()
-  return %3 : $()
-}
-
-sil @insert_release_in_liverange_exit_block : $@convention(thin) () -> () {
-bb0:
-  %2 = function_ref @closure : $@convention(thin) () -> ()
-  %3 = partial_apply %2() : $@convention(thin) () -> ()
-  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %5 = partial_apply %8(%3) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-
-  // There is a critical edge from bb0 to bb2 which is broken by ValueLifetimeAnalysis.
-  cond_br undef, bb2, bb1
-
-bb1:
-  strong_retain %3 : $@callee_owned () -> ()
-  strong_retain %3 : $@callee_owned () -> ()
-  %10 = function_ref @use_closure2 : $@convention(thin) (@owned @callee_owned () -> (), @owned @callee_owned () -> ()) -> ()
-
-  // Passing two closures actually prevents closure specialization.
-  %17 = apply %10(%3, %3) : $@convention(thin) (@owned @callee_owned () -> (), @owned @callee_owned () -> ()) -> ()
-  br bb2
-
-bb2:
-  strong_release %5 : $@callee_owned () -> ()
-  %11 = tuple ()
-  return %11 : $()
-}
diff --git a/test/SILOptimizer/closure_specialize_block.swift b/test/SILOptimizer/closure_specialize_block.swift
new file mode 100644
index 0000000000000..30e5b758b4931
--- /dev/null
+++ b/test/SILOptimizer/closure_specialize_block.swift
@@ -0,0 +1,20 @@
+// RUN: %target-swift-frontend -parse-as-library -O %s -emit-sil | %FileCheck %s
+
+func callClosure<R>(_ body: () -> R) -> R {
+  return body()
+}
+
+// Check that after removing a copy_block, no retains+releases are inserted for the block.
+// CHECK-LABEL: sil {{.*}}@testit :
+// CHECK-NOT:     retain
+// CHECK-NOT:     release
+// CHECK:       } // end sil function 'testit'
+@_cdecl("testit")
+public func testit(_ block: (_ index: Int) -> Int) -> Bool {
+  @inline(never)
+  func c() -> Bool {
+	  return block(0) != 0
+  }
+
+	return callClosure(c)
+}
diff --git a/test/SILOptimizer/closure_specialize_fragile.sil b/test/SILOptimizer/closure_specialize_fragile.sil
index 9cd6e3dd2673a..f2bbfecdfb710 100644
--- a/test/SILOptimizer/closure_specialize_fragile.sil
+++ b/test/SILOptimizer/closure_specialize_fragile.sil
@@ -21,11 +21,11 @@ bb0:
   return %0 : $()
 } // end sil function '$s26closure_specialize_fragile6actionyyF'
 
-// CHECK-LABEL: sil [serialized] [always_inline] @$s26closure_specialize_fragile0C6CalleryyF : $@convention(thin) () -> ()
+// CHECK-LABEL: sil [serialized] [heuristic_always_inline] @$s26closure_specialize_fragile0C6CalleryyF : $@convention(thin) () -> ()
 // CHECK: function_ref @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
 // CHECK: return
 // fragileCaller()
-sil [serialized] [always_inline] @$s26closure_specialize_fragile0C6CalleryyF : $@convention(thin) () -> () {
+sil [serialized] [heuristic_always_inline] @$s26closure_specialize_fragile0C6CalleryyF : $@convention(thin) () -> () {
 bb0:
   // function_ref resilientCallee(fn:)
   %0 = function_ref @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
diff --git a/test/SILOptimizer/concat_string_literals.32.swift b/test/SILOptimizer/concat_string_literals.32.swift
index 01390761c8c6d..d84c142397c99 100644
--- a/test/SILOptimizer/concat_string_literals.32.swift
+++ b/test/SILOptimizer/concat_string_literals.32.swift
@@ -4,6 +4,7 @@
 
 // We have a separate test for 64-bit architectures.
 // REQUIRES: PTRSIZE=32
+// XFAIL: OS=linux-androideabi
 
 // NOTE: 25185.byteSwapped = 0x62 'a', 0x61 'b'
 // CHECK-LABEL: test_ascii_scalar_scalar2
diff --git a/test/SILOptimizer/constant_evaluator_test.sil b/test/SILOptimizer/constant_evaluator_test.sil
index 6865425efa67f..1908706e152f0 100644
--- a/test/SILOptimizer/constant_evaluator_test.sil
+++ b/test/SILOptimizer/constant_evaluator_test.sil
@@ -607,7 +607,7 @@ bb0:
 
 // String.init(_builtinStringLiteral:utf8CodeUnitCount:isASCII:)
 // The semantics attribute is used by the interpreter.
-sil [serialized] [always_inline] [readonly] [_semantics "string.makeUTF8"] @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
+sil [serialized] [heuristic_always_inline] [readonly] [_semantics "string.makeUTF8"] @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
 
 // CHECK-LABEL: @interpretStringInitIntrinsic
 sil hidden @interpretStringInitIntrinsic : $@convention(thin) () ->  @owned String {
@@ -1220,7 +1220,7 @@ sil @interpretAssertionFailure : $@convention(thin) () -> Never {
 sil [serialized] [_semantics "array.init.empty"] @$sS2ayxGycfC : $@convention(method) <τ_0_0> (@thin Array<τ_0_0>.Type) -> @owned Array<τ_0_0>
 
 // _allocateUninitializedArray<A>(_:)
-sil [serialized] [always_inline] [_semantics "array.uninitialized_intrinsic"] @$ss27_allocateUninitializedArrayySayxG_BptBwlF : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
+sil [serialized] [heuristic_always_inline] [_semantics "array.uninitialized_intrinsic"] @$ss27_allocateUninitializedArrayySayxG_BptBwlF : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
 
 // CHECK-LABEL: @interpretArrayInit
 sil @interpretArrayInit : $@convention(thin) () -> @owned Array<Int> {
diff --git a/test/SILOptimizer/constant_propagation.sil b/test/SILOptimizer/constant_propagation.sil
index cf2b250397300..809fea7ddfa04 100644
--- a/test/SILOptimizer/constant_propagation.sil
+++ b/test/SILOptimizer/constant_propagation.sil
@@ -1524,7 +1524,7 @@ bb0:
 
 // String.init(_builtinStringLiteral:utf8CodeUnitCount:isASCII:)
 // The semantics attribute is used by the constant folder.
-sil [serialized] [always_inline] [readonly] [_semantics "string.makeUTF8"] @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
+sil [serialized] [heuristic_always_inline] [readonly] [_semantics "string.makeUTF8"] @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
 
 // CHECK-LABEL: sil @string_ptr_to_int_round_trip : $@convention(thin) () -> Builtin.RawPointer {
 // CHECK-NOT: builtin
diff --git a/test/SILOptimizer/constant_propagation_castopt_analysis_invalidation.sil b/test/SILOptimizer/constant_propagation_castopt_analysis_invalidation.sil
index 5e9b2ef33c884..d6b24d3fcb7a9 100644
--- a/test/SILOptimizer/constant_propagation_castopt_analysis_invalidation.sil
+++ b/test/SILOptimizer/constant_propagation_castopt_analysis_invalidation.sil
@@ -175,7 +175,7 @@ bb7(%26 : $()):                                   // Preds: bb4
 }
 
 // main.(speak in _9ACC0692747077F216D14C36CD927671) (main.(Foo in _9ACC0692747077F216D14C36CD927671)) -> ()
-sil private [always_inline] @_TF4mainP33_9ACC0692747077F216D14C36CD9276715speakFCS_P33_9ACC0692747077F216D14C36CD9276713FooT_ : $@convention(thin) (@owned Foo) -> () {
+sil private [heuristic_always_inline] @_TF4mainP33_9ACC0692747077F216D14C36CD9276715speakFCS_P33_9ACC0692747077F216D14C36CD9276713FooT_ : $@convention(thin) (@owned Foo) -> () {
 bb0(%0 : $Foo):
   debug_value %0 : $Foo                           // id: %1
   strong_retain %0 : $Foo                         // id: %2
diff --git a/test/SILOptimizer/constant_propagation_casts_ossa.sil b/test/SILOptimizer/constant_propagation_casts_ossa.sil
index 28886223045de..875d0c9c7abc3 100644
--- a/test/SILOptimizer/constant_propagation_casts_ossa.sil
+++ b/test/SILOptimizer/constant_propagation_casts_ossa.sil
@@ -1,7 +1,13 @@
 // RUN: %target-sil-opt -enable-sil-verify-all %s -diagnostic-constant-propagation | %FileCheck %s
+
+// REQUIRES: concurrency
+
 sil_stage canonical
 
-//import Swift
+import Builtin
+import Swift
+import _Concurrency
+import SwiftShims
 
 class Klass {
 }
@@ -12,6 +18,15 @@ class SubKlass : Klass {
 class NoSubKlass {
 }
 
+protocol P {
+  func f() -> Int
+}
+
+struct X : @MainActor P {
+  func f() -> Int
+  init()
+}
+
 sil [noinline] @blackhole1 : $@convention(thin) (@guaranteed SubKlass) -> ()
 sil [noinline] @blackhole2 : $@convention(thin) (@guaranteed NoSubKlass) -> ()
 
@@ -94,3 +109,26 @@ bb3:
   return %r : $()
 }
 
+// CHECK-LABEL: sil [ossa] @isolated_conf_ucca :
+// CHECK:         unconditional_checked_cast_addr
+// CHECK-LABEL: } // end sil function 'isolated_conf_ucca'
+sil [ossa] @isolated_conf_ucca : $@convention(thin) (@in X) -> @out P {
+bb0(%0 : $*P, %1 : $*X):
+  unconditional_checked_cast_addr X in %1 to any P in %0
+  %2 = tuple ()
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @isolated_conf_ccab :
+// CHECK:         checked_cast_addr_br
+// CHECK-LABEL: } // end sil function 'isolated_conf_ccab'
+sil [ossa] @isolated_conf_ccab : $@convention(thin) (@in X) -> @out P {
+bb0(%0 : $*P, %1 : $*X):
+  checked_cast_addr_br take_always X in %1 to any P in %0, bb1, bb2
+bb1:
+  %2 = tuple ()
+  return %2
+bb2:
+  unreachable
+}
+
diff --git a/test/SILOptimizer/constant_propagation_stdlib.swift b/test/SILOptimizer/constant_propagation_stdlib.swift
index a40e40e29a0a0..90d12d640a786 100644
--- a/test/SILOptimizer/constant_propagation_stdlib.swift
+++ b/test/SILOptimizer/constant_propagation_stdlib.swift
@@ -28,7 +28,7 @@ public func isConcrete_true(_ x: MyInt) -> Builtin.Int1 {
 // CHECK-ONONE:         [[RESULT:%.*]] = integer_literal $Builtin.Int1, 0
 // CHECK-ONONE:         return [[RESULT]]
 // CHECK-ONONE:       } // end sil function '$s27constant_propagation_stdlib16isConcrete_falseyBi1_xlF'
-// CHECK-O-LABEL:     sil [signature_optimized_thunk] [always_inline] {{.*}}@$s27constant_propagation_stdlib16isConcrete_falseyBi1_xlF : $@convention(thin) <T> (@in_guaranteed T) -> Builtin.Int1 {
+// CHECK-O-LABEL:     sil [signature_optimized_thunk] [heuristic_always_inline] {{.*}}@$s27constant_propagation_stdlib16isConcrete_falseyBi1_xlF : $@convention(thin) <T> (@in_guaranteed T) -> Builtin.Int1 {
 // CHECK-O:           bb0(
 // CHECK-O:             [[GEN_FUNC:%.*]] = function_ref @$s27constant_propagation_stdlib16isConcrete_falseyBi1_xlFTf4d_n : $@convention(thin) <τ_0_0> () -> Builtin.Int1
 // CHECK-O:             [[RESULT:%.*]] = apply [[GEN_FUNC]]<T>() : $@convention(thin) <τ_0_0> () -> Builtin.Int1
diff --git a/test/SILOptimizer/consume_operator_kills_copyable_values.swift b/test/SILOptimizer/consume_operator_kills_copyable_values.swift
index e6ac631358637..a5d786ccaf040 100644
--- a/test/SILOptimizer/consume_operator_kills_copyable_values.swift
+++ b/test/SILOptimizer/consume_operator_kills_copyable_values.swift
@@ -6,6 +6,10 @@ public class Klass {}
 public class SubKlass1 : Klass {}
 public class SubKlass2 : Klass {}
 
+struct A {
+    var prop = ""
+}
+
 //////////////////
 // Declarations //
 //////////////////
@@ -14,6 +18,14 @@ func consumingUse(_ k: __owned Klass) {}
 var booleanValue: Bool { false }
 func nonConsumingUse(_ k: Klass) {}
 
+func consumeValue<V>(_ v: consuming V) {}
+func borrowValue<V>(_ v: borrowing V) {}
+func useValue<V>(_ v: V) {}
+
+func consumeA(_ a: consuming A) {}
+func borrowA(_ a: borrowing A) {}
+func useA(_ a: A) {}
+
 ///////////
 // Tests //
 ///////////
@@ -424,3 +436,37 @@ public func deferTest(_ x: __owned Klass) { // expected-error {{'x' used after c
     }
     print("do Something")
 }
+
+
+/////////////////////////
+// Local Binding Tests //
+/////////////////////////
+
+func testLocalBindingUseAfterConsumeGenerics() {
+    let a = A()         // expected-error {{'a' used after consume}}
+    _ = consume a       // expected-note {{consumed here}}
+    consumeValue(a)     // expected-note {{used here}}
+    borrowValue(a)      // expected-note {{used here}}
+    useValue(a)         // expected-note {{used here}}
+}
+
+func testLocalBindingUseAfterConsumeNoGenericFuncs() {
+    let a = A()     // expected-error {{'a' used after consume}}
+    _ = consume a   // expected-note {{consumed here}}
+
+    consumeA(a) // expected-note {{used here}}
+    borrowA(a)  // expected-note {{used here}}
+    useA(a)     // expected-note {{used here}}
+}
+
+// https://github.com/swiftlang/swift/issues/83277
+func test_83277() {
+    let values = [1, 2, 3]  // expected-error {{'values' used after consume}}
+    var newValues = consume values // expected-note {{consumed here}}
+    newValues.append(4)
+
+    _ = values.count    // expected-note {{used here}}
+    _ = values[0]       // expected-note {{used here}}
+    _ = values.first    // expected-note {{used here}}
+    _ = values.last     // expected-note {{used here}}
+}
diff --git a/test/SILOptimizer/copy-to-borrow-optimization.sil b/test/SILOptimizer/copy-to-borrow-optimization.sil
index 845324ca7f615..3f27a8cf4f2a4 100644
--- a/test/SILOptimizer/copy-to-borrow-optimization.sil
+++ b/test/SILOptimizer/copy-to-borrow-optimization.sil
@@ -1,4 +1,5 @@
 // RUN: %target-sil-opt -copy-to-borrow-optimization %s | %FileCheck %s
+// REQUIRES: macosx
 
 sil_stage canonical
 
@@ -87,6 +88,7 @@ sil @use_inguaranteed : $@convention(thin) (@in_guaranteed Klass) -> ()
 sil @guaranteed_fakeoptional_klass_user : $@convention(thin) (@guaranteed FakeOptional<Klass>) -> ()
 sil @guaranteed_fakeoptional_classlet_user : $@convention(thin) (@guaranteed FakeOptional<ClassLet>) -> ()
 sil @closure : $@convention(thin) (@inout_aliasable Klass) -> ()
+sil @lendC : $@yield_once_2 @convention(thin) () -> @yields @guaranteed C
 sil @useC : $@convention(thin) (@guaranteed C) -> () {
 [global:]
 }
@@ -2202,3 +2204,59 @@ bb3:
   %r = tuple ()
   return %r
 }
+
+
+// CHECK-LABEL: sil [ossa] @keep_yield2ed_copy : {{.*}} {
+// CHECK:         copy_value
+// CHECK:       } // end sil function 'keep_yield2ed_copy'
+sil [ossa] @keep_yield2ed_copy : $@convention(thin) () -> () {
+  %lendC = function_ref @lendC : $@yield_once_2 @convention(thin) () -> @yields @guaranteed C
+  (%c, %token, %alloc) = begin_apply %lendC()  : $@yield_once_2 @convention(thin) () -> @yields @guaranteed C
+  %copy = copy_value %c : $C
+  end_apply %token as $()
+  dealloc_stack %alloc : $*Builtin.SILToken
+  %useC = function_ref @useC : $@convention(thin) (@guaranteed C) -> ()
+  apply %useC(%copy) : $@convention(thin) (@guaranteed C) -> ()
+  destroy_value %copy : $C
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: sil [ossa] @borrowed_from_forward1 : {{.*}} {
+// CHECK-NOT:   copy_value
+// CHECK-LABEL: } // end sil function 'borrowed_from_forward1'
+sil [ossa] @borrowed_from_forward1 : $@convention(thin) (@guaranteed C) -> () {
+bb0(%0 : @guaranteed $C):
+  br bb1(%0)
+
+bb1(%1 : @guaranteed $C):
+  %2 = borrowed %1 from (%0)
+  %copy = copy_value %2
+  %useC = function_ref @useC : $@convention(thin) (@guaranteed C) -> ()
+  apply %useC(%copy) : $@convention(thin) (@guaranteed C) -> ()
+  destroy_value %copy
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: sil [ossa] @borrowed_from_forward2 : {{.*}} {
+// CHECK-NOT:   copy_value
+// CHECK-LABEL: } // end sil function 'borrowed_from_forward2'
+sil [ossa] @borrowed_from_forward2 : $@convention(thin) (@guaranteed Array<Int>) -> () {
+bb0(%0 : @guaranteed $Array<Int>):
+  %1 = struct_extract %0, #Array._buffer
+  %2 = struct_extract %1, #_ArrayBuffer._storage
+  %3 = struct_extract %2, #_BridgeStorage.rawValue
+  %4 = unchecked_ref_cast %3 to $__ContiguousArrayStorageBase
+  br bb1(%4)
+
+bb1(%6 : @guaranteed $__ContiguousArrayStorageBase):
+  %7 = borrowed %6 from (%0)
+  %8 = copy_value %7
+  %9 = begin_borrow %8
+  %10 = ref_element_addr [immutable] %9, #__ContiguousArrayStorageBase.countAndCapacity
+  end_borrow %9
+  destroy_value %8
+  %13 = tuple ()
+  return %13
+}
diff --git a/test/SILOptimizer/copy_propagation.sil b/test/SILOptimizer/copy_propagation.sil
index 70d829537fd2d..c1a325d32b1af 100644
--- a/test/SILOptimizer/copy_propagation.sil
+++ b/test/SILOptimizer/copy_propagation.sil
@@ -1094,3 +1094,58 @@ bb0:
   return %3
 }
 
+class Klass {}
+
+public struct Wrapper {
+  var _k: Klass
+  var i: Int
+}
+
+sil @get_wrapper : $@convention(thin) () -> @owned Wrapper
+sil @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+
+sil [ossa] [noinline] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+bb0(%0 : @guaranteed $Wrapper):
+  %2 = struct_extract %0, #Wrapper._k
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @test_borrow_accessor_opt1 :
+// CHECK-NOT: copy_value
+// CHECK-LABEL: } // end sil function 'test_borrow_accessor_opt1'
+sil [ossa] @test_borrow_accessor_opt1 : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  %copy = copy_value %0
+  %1 = begin_borrow %copy
+  %2 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %3 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %4 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %5 = apply %4(%3) : $@convention(thin) (@guaranteed Klass) -> ()
+  end_borrow %1
+  destroy_value %copy
+  destroy_value %0
+  %6 = tuple ()
+  return %6
+}
+
+// SemanticArcOpts removes the copy_value in this test
+// CHECK-LABEL: sil [ossa] @test_borrow_accessor_opt2 :
+// TODO-CHECK-NOT: copy_value
+// CHECK-LABEL: } // end sil function 'test_borrow_accessor_opt2'
+sil [ossa] @test_borrow_accessor_opt2 : $@convention(thin) () -> () {
+bb0:
+  %1 = function_ref @get_wrapper : $@convention(thin) () -> @owned Wrapper
+  %2 = apply %1() : $@convention(thin) () -> @owned Wrapper
+  %3 = begin_borrow %2
+  %4 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %5 = apply %4(%3) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %copy = copy_value %5
+  %6 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %7 = apply %6(%copy) : $@convention(thin) (@guaranteed Klass) -> ()
+  destroy_value %copy
+  end_borrow %3
+  destroy_value %2
+  %10 = tuple ()
+  return %10
+}
+
diff --git a/test/SILOptimizer/copy_propagation.swift b/test/SILOptimizer/copy_propagation.swift
index 66f07e127472d..edb06285af2c3 100644
--- a/test/SILOptimizer/copy_propagation.swift
+++ b/test/SILOptimizer/copy_propagation.swift
@@ -1,4 +1,8 @@
-// RUN: %target-swift-frontend -primary-file %s -O -sil-verify-all -module-name=test -emit-sil | %FileCheck %s
+// RUN: %target-swift-frontend -primary-file %s -O \
+// RUN:   -sil-verify-all -module-name=test -emit-sil | %FileCheck %s
+
+// RUN: %target-swift-frontend -primary-file %s -Onone -enable-copy-propagation \
+// RUN:    -sil-verify-all -module-name=test -emit-sil | %FileCheck %s --check-prefix ONONE
 
 // REQUIRES: swift_in_compiler
 
@@ -21,6 +25,20 @@ func borrow(_ c: C)
 // CHECK:         [[NON_BARRIER:%[^,]+]] = function_ref @non_barrier
 // CHECK:         apply [[NON_BARRIER]]()
 // CHECK-LABEL: } // end sil function 'test_hoist_over_non_barrier'
+
+
+/////
+// NOTE: in -Onone, the release is NOT hoisted, to preserve debugging.
+
+// ONONE-LABEL: sil {{.*}}@test_hoist_over_non_barrier : {{.*}} {
+// ONONE:         [[INSTANCE:%[^,]+]] = apply {{.*}} -> @owned C
+// ONONE:         debug_value [[INSTANCE]], let, name "c"
+// ONONE:         [[BORROW:%[^,]+]] = function_ref @borrow
+// ONONE:         apply [[BORROW]]([[INSTANCE]])
+// ONONE:         [[NON_BARRIER:%[^,]+]] = function_ref @non_barrier
+// ONONE:         apply [[NON_BARRIER]]()
+// ONONE:         strong_release [[INSTANCE]]
+// ONONE-LABEL: } // end sil function 'test_hoist_over_non_barrier'
 @_silgen_name("test_hoist_over_non_barrier")
 func test_hoist_over_non_barrier() {
   let c = C()
@@ -28,3 +46,67 @@ func test_hoist_over_non_barrier() {
   non_barrier()
 }
 
+// CHECK-LABEL: sil {{.*}}@reassign_with_lets : {{.*}} {
+// CHECK:           [[INSTANCE:%[^,]+]] = alloc_ref $C
+// CHECK:           [[EI:%.*]] = end_init_let_ref [[INSTANCE]]
+// CHECK-NEXT:      debug_value [[EI]], let, name "x"
+// CHECK-NEXT:      debug_value [[EI]], let, name "y"
+// CHECK-NEXT:      debug_value [[EI]], let, name "z"
+// CHECK-NEXT:      return [[EI]]
+// CHECK-LABEL: } // end sil function 'reassign_with_lets'
+
+// ONONE-LABEL: sil {{.*}}@reassign_with_lets : {{.*}} {
+// ONONE:           [[INSTANCE:%[^,]+]] = apply {{.*}} -> @owned C
+// ONONE-NEXT:      debug_value [[INSTANCE]], let, name "x"
+// ONONE-NEXT:      debug_value [[INSTANCE]], let, name "y"
+// ONONE-NEXT:      debug_value [[INSTANCE]], let, name "z"
+// ONONE-NEXT:      return [[INSTANCE]]
+// ONONE-LABEL: } // end sil function 'reassign_with_lets'
+@_silgen_name("reassign_with_lets")
+func reassign_with_lets() -> C {
+  let x = C()
+  let y = x
+  let z = y
+  return z
+}
+
+// CHECK-LABEL: sil {{.*}}@renamed_return : {{.*}} {
+// CHECK-NOT:       strong_retain
+// CHECK:           debug_value %1, let, name "a"
+// CHECK-NEXT:      debug_value %1, let, name "b"
+// CHECK-NEXT:      debug_value %1, let, name "c"
+// CHECK-NEXT:      strong_retain %1
+// CHECK-NEXT:      return %1
+// CHECK-LABEL: } // end sil function 'renamed_return'
+
+
+/////
+// Slightly different control-flow in -Onone, but still one
+// retain dynamically executed on the object.
+
+// ONONE-LABEL: sil {{.*}}@renamed_return : {{.*}} {
+// ONONE-NOT:       strong_retain
+// ONONE:           debug_value %1, let, name "a"
+// ONONE-NEXT:      debug_value %1, let, name "b"
+// ONONE-NEXT:      debug_value %1, let, name "c"
+// ONONE: cond_br {{.*}} bb1, bb2
+
+// ONONE: bb1
+// ONONE:           strong_retain %1
+// ONONE:           br bb3
+
+// ONONE: bb2
+// ONONE:           strong_retain %1
+// ONONE:           br bb3
+
+// ONONE: bb3
+// ONONE-NEXT:      return
+// ONONE-LABEL: } // end sil function 'renamed_return'
+@_silgen_name("renamed_return")
+func renamed_return(_ cond: Bool, _ a: C) -> C {
+  let b = a
+  let c = b
+  if cond { return b }
+  return c
+}
+
diff --git a/test/SILOptimizer/copy_propagation_borrow.sil b/test/SILOptimizer/copy_propagation_borrow.sil
index 501cc1a7338d7..e8c4fca35810f 100644
--- a/test/SILOptimizer/copy_propagation_borrow.sil
+++ b/test/SILOptimizer/copy_propagation_borrow.sil
@@ -1041,7 +1041,7 @@ bb0(%0 : @guaranteed $C):
 }
 
 // TODO: Remove this copy inside a borrow scope by shrinking the scope .
-// rdar://79149830 (Shrink borrow scopes in CanonicalizeBorrowScope)
+// rdar://79149830 (Shrink borrow scopes in OSSACanonicalizeGuaranteed)
 //
 // Note: shrinking borrow scopes needs to happen even when most borrow
 // scopes are eliminated because some "defined" borrow scopes cannot be removed.
@@ -1070,7 +1070,7 @@ bb0(%0 : @owned $HasObject):
 // Test a more complicated/realistic example of useless borrows
 //
 // TODO: Remove this copy inside a borrow scope by shrinking the scope .
-// rdar://79149830 (Shrink borrow scopes in CanonicalizeBorrowScope)
+// rdar://79149830 (Shrink borrow scopes in OSSACanonicalizeGuaranteed)
 //
 // It only has one trivial struct_extract. But copy propagation
 // currently only removes completely dead borrows.
diff --git a/test/SILOptimizer/cse.sil b/test/SILOptimizer/cse.sil
index f5ebcf8262040..a385801148cc3 100644
--- a/test/SILOptimizer/cse.sil
+++ b/test/SILOptimizer/cse.sil
@@ -1447,4 +1447,3 @@ bb0:
   %r1 = tuple ()
   return %r1 : $()
 }
-
diff --git a/test/SILOptimizer/cse_objc_ossa.sil b/test/SILOptimizer/cse_objc_ossa.sil
index 8be52c7a1a9d4..dd02d72cb6b2e 100644
--- a/test/SILOptimizer/cse_objc_ossa.sil
+++ b/test/SILOptimizer/cse_objc_ossa.sil
@@ -14,12 +14,13 @@ import Foundation
 // CHECK-NOT: objc_protocol
 // CHECK: tuple (%0 : $Protocol, %0 : $Protocol)
 // CHECK-LABEL: } // end sil function 'cse_objc_protocol'
-sil [ossa] @cse_objc_protocol : $@convention(thin) () -> (Protocol, Protocol) {
+sil [ossa] @cse_objc_protocol : $@convention(thin) () -> @owned (Protocol, Protocol) {
 bb0:
   %0 = objc_protocol #XX : $Protocol
   %1 = objc_protocol #XX : $Protocol
   %2 = tuple (%0: $Protocol, %1: $Protocol)
-  return %2 : $(Protocol, Protocol)
+  %3 = copy_value %2
+  return %3
 }
 
 @objc protocol Walkable {
diff --git a/test/SILOptimizer/cse_ossa.sil b/test/SILOptimizer/cse_ossa.sil
index c96da0ffb9bbb..eb36b26620d22 100644
--- a/test/SILOptimizer/cse_ossa.sil
+++ b/test/SILOptimizer/cse_ossa.sil
@@ -700,12 +700,13 @@ bb0(%0 : $*Builtin.Int8):
 // CHECK-NOT: raw_pointer_to_ref
 // CHECK: tuple
 // CHECK-LABEL: } // end sil function 'cse_raw_pointer_to_ref'
-sil [ossa] @cse_raw_pointer_to_ref : $@convention(thin) (Builtin.RawPointer) -> (C, C) {
+sil [ossa] @cse_raw_pointer_to_ref : $@convention(thin) (Builtin.RawPointer) -> @owned (C, C) {
 bb0(%0 : $Builtin.RawPointer):
   %1 = raw_pointer_to_ref %0 : $Builtin.RawPointer to $C
   %2 = raw_pointer_to_ref %0 : $Builtin.RawPointer to $C
   %6 = tuple(%1: $C, %2: $C)
-  return %6 : $(C, C)
+  %7 = copy_value %6
+  return %7
 }
 
 // CHECK-LABEL: sil [ossa] @cse_unchecked_addr_cast :
@@ -1062,7 +1063,7 @@ bb0(%0 : $*Builtin.Int64, %1 : @guaranteed $Builtin.NativeObject):
   return %6 : $(Builtin.Int64, Builtin.Int64)
 }
 
-protocol Proto : class {
+protocol Proto : AnyObject {
   func doThis()
   func doThat()
 }
@@ -1351,3 +1352,16 @@ bb0(%0 : $*InlineArray<N, Int>, %1 : $Int):
   return %14
 }
 
+struct Pair<let x: Int, let y: Int> {}
+// CHECK-LABEL: sil [ossa] @dont_cse_different_type_values : {{.*}} {
+// CHECK:         type_value
+// CHECK:         type_value
+// CHECK-LABEL: } // end sil function 'dont_cse_different_type_values'
+sil [ossa] @dont_cse_different_type_values : $@convention(method) <let x : Int, let y : Int> (Pair<x, y>) -> (Int, Int) {
+[global: ]
+bb0(%0 : $Pair<x, y>):
+  %2 = type_value $Int for x
+  %3 = type_value $Int for y
+  %4 = tuple (%2, %3)
+  return %4
+}
diff --git a/test/SILOptimizer/cse_ossa_nontrivial.sil b/test/SILOptimizer/cse_ossa_nontrivial.sil
index c2d7e9881e07b..bb119dcb00f0b 100644
--- a/test/SILOptimizer/cse_ossa_nontrivial.sil
+++ b/test/SILOptimizer/cse_ossa_nontrivial.sil
@@ -255,19 +255,6 @@ bb0(%0 : @owned $Klass):
   return %6 : $()
 }
 
-// CHECK-LABEL: sil [ossa] @cse_raw_pointer_to_ref :
-// CHECK: raw_pointer_to_ref
-// CHECK-NOT: raw_pointer_to_ref
-// CHECK: tuple
-// CHECK-LABEL: } // end sil function 'cse_raw_pointer_to_ref'
-sil [ossa] @cse_raw_pointer_to_ref : $@convention(thin) (Builtin.RawPointer) -> (Klass, Klass) {
-bb0(%0 : $Builtin.RawPointer):
-  %1 = raw_pointer_to_ref %0 : $Builtin.RawPointer to $Klass
-  %2 = raw_pointer_to_ref %0 : $Builtin.RawPointer to $Klass
-  %6 = tuple(%1: $Klass, %2: $Klass)
-  return %6 : $(Klass, Klass)
-}
-
 enum Enum1 {
     case Case1
     case Case2
@@ -1126,3 +1113,76 @@ bb0:
   %res = tuple ()
   return %res : $()
 }
+
+// testMoveEnumChangesOwnership requires HasOptC and HasOptC to declare
+// their properties with @_hasStorage.
+public struct HasOptKlass {
+  @_hasStorage let c: Klass? { get }
+}
+
+public struct HasOptKlassHolder {
+  @_hasStorage public var hasOptKlass: HasOptKlass { get set }
+}
+
+// CHECK-LABEL: sil [ossa] @testMoveEnumChangesOwnership : $@convention(thin) () -> () {
+// CHECK:   [[E1:%[0-9]+]] = enum $Optional<Klass>, #Optional.none!enumelt
+// CHECK:   [[MV1:%[0-9]+]] = move_value [lexical] [[E1]] : $Optional<Klass>
+// CHECK:   [[S:%[0-9]+]] = struct $HasOptKlass (%0 : $Optional<Klass>)
+// CHECK:   store [[S]] to [init]
+// CHECK:   destroy_value [[MV1]] : $Optional<Klass>
+// CHECK:   [[MV2:%[0-9]+]] = move_value [lexical] [[S]] : $HasOptKlass
+// CHECK:   store [[MV2]] to [assign]
+// CHECK: } // end sil function 'testMoveEnumChangesOwnership'
+sil [ossa] @testMoveEnumChangesOwnership : $@convention(thin) () -> () {
+bb0:
+  %0 = enum $Optional<Klass>, #Optional.none!enumelt
+  %1 = move_value [lexical] %0
+  %2 = alloc_stack [lexical] [var_decl] $HasOptKlassHolder
+  %3 = enum $Optional<Klass>, #Optional.none!enumelt
+  %4 = struct $HasOptKlass (%3)
+  %5 = struct_element_addr %2, #HasOptKlassHolder.hasOptKlass
+  store %4 to [init] %5
+  %7 = struct $HasOptKlass (%1)
+  %8 = move_value [lexical] %7
+  store %8 to [assign] %5
+  %10 = load [take] %2
+  dealloc_stack %2
+  destroy_value %10
+  %13 = tuple ()
+  return %13
+}
+
+/// A scenario where a borrow of a copy is introduced but the cfg is such that
+/// no end_borrows are inserted for the borrow.  The copy must still be
+/// destroyed.
+// CHECK-LABEL: sil [ossa] @no_boundary_for_end_borrows : {{.*}} {
+// TODO: There shouldn't actually be a copy_value here, but lifetime transfer
+//       APIs are written and OSSARAUWHelper is in use, there will be.
+//       Even then, this test case shouldn't crash.
+// CHECK:         copy_value
+// CHECK:         destroy_value
+// CHECK-LABEL: } // end sil function 'no_boundary_for_end_borrows'
+sil [ossa] @no_boundary_for_end_borrows : $@convention(thin) (@guaranteed NonTrivialStruct) -> () {
+entry(%s : @guaranteed $NonTrivialStruct):
+  %c1 = struct_extract %s : $NonTrivialStruct, #NonTrivialStruct.val
+  cond_br undef, loop_entry, exit
+
+exit:
+  apply undef(%c1) : $@convention(thin) (@guaranteed Klass) -> ()
+  return undef : $()
+
+loop_entry:
+  %c2 = struct_extract %s : $NonTrivialStruct, #NonTrivialStruct.val
+  apply undef(%c2) : $@convention(thin) (@guaranteed Klass) -> ()
+  br loop_header
+
+loop_header:
+  apply undef(%c2) : $@convention(thin) (@guaranteed Klass) -> ()
+  cond_br undef, die, loop_backedge
+
+loop_backedge:
+  br loop_header
+
+die:
+  unreachable
+}
diff --git a/test/SILOptimizer/dead_alloc_elim.sil b/test/SILOptimizer/dead_alloc_elim.sil
index cb58464087a90..856bcaf599845 100644
--- a/test/SILOptimizer/dead_alloc_elim.sil
+++ b/test/SILOptimizer/dead_alloc_elim.sil
@@ -721,3 +721,15 @@ bb0:
   %1 = tuple ()
   return %1 : $()
 }
+
+// CHECK-LABEL: @dead_prepare_init
+// CHECK-NOT: alloc_stack
+// // CHECK: } // end sil function 'dead_prepare_init'
+sil @dead_prepare_init : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_stack $Kl
+  %empty = builtin "prepareInitialization"(%0 : $*Kl) : $()
+  dealloc_stack %0 : $*Kl
+  %1 = tuple ()
+  return %1 : $()
+}
diff --git a/test/SILOptimizer/dead_array_elim.swift b/test/SILOptimizer/dead_array_elim.swift
index 4b2b12865aed3..8426e66c7e0fd 100644
--- a/test/SILOptimizer/dead_array_elim.swift
+++ b/test/SILOptimizer/dead_array_elim.swift
@@ -2,11 +2,6 @@
 
 // REQUIRES: swift_stdlib_no_asserts
 // REQUIRES: swift_in_compiler
-// XFAIL: OS=linux-androideabi
-
-// Test needs to be updated for 32bit.
-// rdar://74810823
-// UNSUPPORTED: PTRSIZE=32
 
 // These tests check whether DeadObjectElimination pass runs as a part of the
 // optimization pipeline and eliminates dead array literals in Swift code.
diff --git a/test/SILOptimizer/dead_code_elimination_nontrivial_ossa.sil b/test/SILOptimizer/dead_code_elimination_nontrivial_ossa.sil
index e2d105fa66009..7089ac1fbb62e 100644
--- a/test/SILOptimizer/dead_code_elimination_nontrivial_ossa.sil
+++ b/test/SILOptimizer/dead_code_elimination_nontrivial_ossa.sil
@@ -514,7 +514,7 @@ bb1(%newborrow : @guaranteed $Klass, %borrow2 : @guaranteed $Klass):
 // Here %newborrowo and %newborrowi are both dead phis.
 // First end_borrow for the incoming value of %newborrowi is added
 // It is non straight forward to find the insert pt for the end_borrow of the incoming value of %newborrowo
-// This may not be important once CanonicalizeOSSALifetime supports rewrite of multi-block borrows.
+// This may not be important once OSSACanonicalizeOwned supports rewrite of multi-block borrows.
 sil [ossa] @dce_nestedborrowlifetime3 : $@convention(thin) (@guaranteed Klass) -> () {
 bb0(%0 : @guaranteed $Klass):
   %borrowo = begin_borrow %0 : $Klass
diff --git a/test/SILOptimizer/dead_code_elimination_ossa.sil b/test/SILOptimizer/dead_code_elimination_ossa.sil
index 1c6b5398904dd..15523cf24fdf9 100644
--- a/test/SILOptimizer/dead_code_elimination_ossa.sil
+++ b/test/SILOptimizer/dead_code_elimination_ossa.sil
@@ -15,12 +15,18 @@ class C {}
 
 sil @getC : $@convention(thin) () -> @owned C
 sil @barrier : $@convention(thin) () -> ()
+sil @initC : $@convention(thin) (Builtin.Word) -> (@owned C, Builtin.RawPointer)
+sil [readnone] @finalC : $@convention(thin) (@owned C) -> @owned C
 
 struct CAndBit {
     var c: C
     var bit: Int1
 }
 
+struct Bool {
+  var _value: Builtin.Int1
+}
+
 struct MO: ~Copyable {
   var x: Int
   deinit
@@ -507,3 +513,28 @@ bb0(%0 : @owned $Outer):
   return %6 : $()
 }
 
+// CHECK-LABEL: sil [ossa] @dont_remove_lifetime_end_of_escaping_value
+// CHECK:         [[FINALIZE:%[^,]+]] = function_ref @finalC
+// CHECK:         apply [[FINALIZE]]
+// CHECK-LABEL: } // end sil function 'dont_remove_lifetime_end_of_escaping_value'
+sil [ossa] @dont_remove_lifetime_end_of_escaping_value : $@convention(thin) (Bool) -> () {
+bb0(%0 : $Bool):
+  %1 = integer_literal $Builtin.Word, 1
+  %2 = function_ref @initC : $@convention(thin) (Builtin.Word) -> (@owned C, Builtin.RawPointer)
+  %3 = apply %2(%1) : $@convention(thin) (Builtin.Word) -> (@owned C, Builtin.RawPointer)
+  (%4, %5) = destructure_tuple %3
+  %6 = mark_dependence %5 on %4
+  %7 = pointer_to_address %6 to [strict] $*Bool
+  store %0 to [trivial] %7
+  br bb1
+
+bb1:
+  %13 = function_ref @finalC : $@convention(thin) (@owned C) -> @owned C
+  %14 = apply %13(%4) : $@convention(thin) (@owned C) -> @owned C
+  destroy_value %14
+  br bb2
+
+bb2:
+  %17 = tuple ()
+  return %17
+}
diff --git a/test/SILOptimizer/dead_end_blocks.sil b/test/SILOptimizer/dead_end_blocks.sil
index 6bc6e24935956..4332fa66370b7 100644
--- a/test/SILOptimizer/dead_end_blocks.sil
+++ b/test/SILOptimizer/dead_end_blocks.sil
@@ -47,4 +47,64 @@ exit:
   return %retval : $()
 }
 
+// no dead ends - simple return
+// CHECK-LABEL: begin running test {{.*}} on simple_function: has_any_dead_ends
+// CHECK:         no dead ends
+// CHECK-LABEL: end running test {{.*}} on simple_function: has_any_dead_ends
+sil @simple_function : $@convention(thin) () -> () {
+entry:
+  specify_test "has_any_dead_ends"
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// dead ends - unreachable blocks
+// CHECK-LABEL: begin running test {{.*}} on function_with_dead_ends: has_any_dead_ends
+// CHECK:         has dead ends
+// CHECK-LABEL: end running test {{.*}} on function_with_dead_ends: has_any_dead_ends
+sil @function_with_dead_ends : $@convention(thin) () -> () {
+entry:
+  specify_test "has_any_dead_ends"
+  cond_br undef, die, exit
+
+die:
+  unreachable
+
+exit:
+  %retval = tuple ()
+  return %retval : $()
+}
 
+// dead ends – infinite loop
+// CHECK-LABEL: begin running test {{.*}} on function_with_loop: has_any_dead_ends
+// CHECK:         has dead ends
+// CHECK-LABEL: end running test {{.*}} on function_with_loop: has_any_dead_ends
+sil @function_with_loop : $@convention(thin) () -> () {
+entry:
+  specify_test "has_any_dead_ends"
+  cond_br undef, exit, loop
+
+loop:
+  br loop
+
+exit:
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// no dead ends – conditional branches but all paths return
+// CHECK-LABEL: begin running test {{.*}} on branching_no_dead_ends: has_any_dead_ends
+// CHECK:         no dead ends
+// CHECK-LABEL: end running test {{.*}} on branching_no_dead_ends: has_any_dead_ends
+sil @branching_no_dead_ends : $@convention(thin) () -> () {
+entry:
+  specify_test "has_any_dead_ends"
+  cond_br undef, then, else
+
+then:
+  br else
+
+else:
+  %retval2 = tuple ()
+  return %retval2 : $()
+}
diff --git a/test/SILOptimizer/dead_store_elim.sil b/test/SILOptimizer/dead_store_elim.sil
index 4cd51cceba8f7..c55bc4992cc9e 100644
--- a/test/SILOptimizer/dead_store_elim.sil
+++ b/test/SILOptimizer/dead_store_elim.sil
@@ -1615,6 +1615,17 @@ bb0(%0 : $Int, %1 : @owned $IntAndFoo, %2 : $*IntAndFoo):
   return %r : $()
 }
 
+// We don't support this, yet.
+// Just check that we don't crash.
+sil [ossa] @test_trivial_store_of_non_trivial_enum : $@convention(thin) (@owned Optional<String>) -> @out Optional<String> {
+bb0(%0 : $*Optional<String>, %1 : @owned $Optional<String>):
+  %2 = enum $Optional<String>, #Optional.none!enumelt
+  store %2 to [trivial] %0
+  store %1 to [assign] %0
+  %r = tuple ()
+  return %r
+}
+
 // CHECK-LABEL: sil @test_bind_memory  :
 // CHECK:         store %0
 // CHECK:       end sil function 'test_bind_memory'
diff --git a/test/SILOptimizer/deadargsignatureopt.sil b/test/SILOptimizer/deadargsignatureopt.sil
index 9efb6071f3be1..5c5361ab3f2e5 100644
--- a/test/SILOptimizer/deadargsignatureopt.sil
+++ b/test/SILOptimizer/deadargsignatureopt.sil
@@ -5,7 +5,7 @@ import Swift
 
 // Specialize to a function with removed dead argument.
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @one_arg_dead
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @one_arg_dead
 // CHECK: [[F:%[0-9]+]] = function_ref @$s12one_arg_deadTf4nnd_n
 // CHECK: [[A:%[0-9]+]] = apply [[F]](%0, %1)
 // CHECK: return [[A]]
@@ -18,11 +18,11 @@ bb0(%0 : $Int32, %1 : $Int32, %2 : $@thin Int32.Type):
   return %8 : $Bool
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @always_inline_one_arg_dead
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @always_inline_one_arg_dead
 // CHECK: [[F:%[0-9]+]] = function_ref @$s26always_inline_one_arg_deadTf4nnd_n
 // CHECK: [[A:%[0-9]+]] = apply [[F]](%0, %1)
 // CHECK: return [[A]]
-sil [always_inline] @always_inline_one_arg_dead : $@convention(witness_method: Comparable) (Int32, Int32, @thin Int32.Type) -> Bool {
+sil [heuristic_always_inline] @always_inline_one_arg_dead : $@convention(witness_method: Comparable) (Int32, Int32, @thin Int32.Type) -> Bool {
 bb0(%0 : $Int32, %1 : $Int32, %2 : $@thin Int32.Type):
   %5 = struct_extract %0 : $Int32, #Int32._value
   %6 = struct_extract %1 : $Int32, #Int32._value
@@ -33,7 +33,7 @@ bb0(%0 : $Int32, %1 : $Int32, %2 : $@thin Int32.Type):
 
 // Still delete only one dead arg as only one arg is partially applied.
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @two_args_dead
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @two_args_dead
 // CHECK: [[F:%[0-9]+]] = function_ref @$s13two_args_deadTf4nnd_n
 // CHECK: [[A:%[0-9]+]] = apply [[F]](%0, %1)
 // CHECK: return [[A]]
diff --git a/test/SILOptimizer/definite-init-convert-to-escape.swift b/test/SILOptimizer/definite-init-convert-to-escape.swift
index df7ad7a2e4c15..fccff212f67c2 100644
--- a/test/SILOptimizer/definite-init-convert-to-escape.swift
+++ b/test/SILOptimizer/definite-init-convert-to-escape.swift
@@ -95,7 +95,7 @@ public func returnOptionalEscape() -> (() ->())?
 // NOPEEPHOLE-NEXT:  strong_retain [[V2]]
 // NOPEEPHOLE-NEXT:  [[CVT:%.*]] = convert_escape_to_noescape [[V2]]
 // NOPEEPHOLE-NEXT:  [[SOME:%.*]] = enum $Optional<{{.*}}>, #Optional.some!enumelt, [[V2]]
-// NOPEEPHOLE-NEXT:  [[MDI:%.*]] = mark_dependence [[CVT]] : $@noescape @callee_guaranteed () -> () on [[SOME]] : $Optional<@callee_guaranteed () -> ()>
+// NOPEEPHOLE-NEXT:  [[MDI:%.*]] = mark_dependence [[CVT]] : $@noescape @callee_guaranteed () -> () on [[V2]]
 // NOPEEPHOLE-NEXT:  [[NOESCAPE_SOME:%.*]] = enum $Optional<{{.*}}>, #Optional.some!enumelt, [[MDI]]
 // NOPEEPHOLE-NEXT:  strong_release [[V2]]
 // NOPEEPHOLE-NEXT:  br bb2([[NOESCAPE_SOME]] : $Optional<{{.*}}>, [[SOME]] : $Optional<{{.*}}>, [[SOME]] : $Optional<{{.*}}>)
diff --git a/test/SILOptimizer/definite_init_actor.swift b/test/SILOptimizer/definite_init_actor.swift
index 99a0dd8009f8d..33e48e2c07bf3 100644
--- a/test/SILOptimizer/definite_init_actor.swift
+++ b/test/SILOptimizer/definite_init_actor.swift
@@ -10,6 +10,7 @@
 
 func neverReturn() -> Never { fatalError("quit!") }
 func arbitraryAsync() async {}
+func makeIntOrThrow() throws -> Int { return 0 }
 
 actor BoringActor {
 
@@ -402,3 +403,40 @@ actor Ahmad {
   // CHECK: } // end sil function '$s4test5AhmadCACyYacfc'
   nonisolated init() async {}
 }
+
+// This should not complain about needing self in the defer prior to it being
+// fully initialized.
+actor Customer {
+  var x: Int
+  var y: Int
+
+  // CHECK-LABEL: sil hidden @$s4test8CustomerCACyYaKcfc :
+  init() async throws {
+    // CHECK:      [[GENERIC:%[0-9]+]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+    // CHECK-NEXT: hop_to_executor [[GENERIC]]
+    // CHECK:      [[SELF:%.*]] = end_init_let_ref %0 : $Customer
+
+    defer { print("I have a complaint") }
+
+    // CHECK:       try_apply {{.*}}, error [[FAIL1:bb[0-9]+]]
+    self.x = try makeIntOrThrow()
+
+    // CHECK:       try_apply {{.*}}, error [[FAIL2:bb[0-9]+]]
+    // CHECK:       hop_to_executor [[SELF]] : $Customer
+    self.y = try makeIntOrThrow()
+
+    // CHECK:      [[DEFER:%.*]] = function_ref @$s4test8CustomerCACyYaKcfc6$deferL_yyF :
+    // CHECK-NEXT: apply [[DEFER]]()
+    // CHECK-NEXT: return [[SELF]] : $Customer
+
+    // CHECK:    [[FAIL1]]({{%.*}} : $any Error):
+    // CHECK-NEXT: // function_ref
+    // CHECK-NEXT: [[DEFER:%.*]] = function_ref @$s4test8CustomerCACyYaKcfc6$deferL_yyF :
+    // CHECK-NEXT: apply [[DEFER]]()
+
+    // CHECK:    [[FAIL2]]({{%.*}} : $any Error):
+    // CHECK-NEXT: // function_ref
+    // CHECK-NEXT: [[DEFER:%.*]] = function_ref @$s4test8CustomerCACyYaKcfc6$deferL_yyF :
+    // CHECK-NEXT: apply [[DEFER]]()
+  }
+}
diff --git a/test/SILOptimizer/definite_init_diagnostics.swift b/test/SILOptimizer/definite_init_diagnostics.swift
index 1daa73eff217f..7de0b0b56a3e2 100644
--- a/test/SILOptimizer/definite_init_diagnostics.swift
+++ b/test/SILOptimizer/definite_init_diagnostics.swift
@@ -103,6 +103,7 @@ func test2() {
   
   
   // Weak
+  // expected-warning@+1 {{weak variable 'w1' was never mutated; consider changing to 'let' constant}} {{8-11=let}}
   weak var w1 : SomeClass?
   _ = w1                // ok: default-initialized
 
@@ -110,7 +111,7 @@ func test2() {
   // expected-warning@+3 {{instance will be immediately deallocated because variable 'w2' is 'weak'}}
   // expected-note@+2 {{a strong reference is required to prevent the instance from being deallocated}}
   // expected-note@+1 {{'w2' declared here}}
-  weak var w2 = SomeClass()
+  weak let w2 = SomeClass()
   _ = w2                // ok
   
   
diff --git a/test/SILOptimizer/definite_init_protocol_init.swift b/test/SILOptimizer/definite_init_protocol_init.swift
index 5fc7325dab59e..6c9c2e247c9ac 100644
--- a/test/SILOptimizer/definite_init_protocol_init.swift
+++ b/test/SILOptimizer/definite_init_protocol_init.swift
@@ -99,7 +99,8 @@ struct AddressOnlyStruct : TriviallyConstructible {
 // CHECK-NEXT: apply [[FN]]<AddressOnlyStruct>([[SELF_BOX]], %1, [[METATYPE]])
 // CHECK-NEXT: copy_addr [take] [[SELF_BOX]] to [init] [[SELF]]
 // CHECK-NEXT: dealloc_stack [[SELF_BOX]]
-// CHECK-NEXT: copy_addr [take] [[SELF]] to [init] %0
+// CHECK-NEXT: copy_addr [[SELF]] to [init] %0
+// CHECK-NEXT: destroy_addr [[SELF]]
 // CHECK-NEXT: dealloc_stack [[SELF]]
 // CHECK-NEXT: [[RESULT:%.*]] = tuple ()
 // CHECK-NEXT: return [[RESULT]]
diff --git a/test/SILOptimizer/destroy-hoisting.sil b/test/SILOptimizer/destroy-hoisting.sil
index c5889e62060c0..c4c9b96746ce6 100644
--- a/test/SILOptimizer/destroy-hoisting.sil
+++ b/test/SILOptimizer/destroy-hoisting.sil
@@ -395,3 +395,58 @@ bb2:
   unreachable
 }
 
+
+public struct Wrapper {
+  var _k: Klass
+  var i: Int
+}
+
+sil @get_wrapper : $@convention(thin) () -> @owned Wrapper
+sil @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+
+sil [ossa] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+bb0(%0 : @guaranteed $Wrapper):
+  %2 = struct_extract %0, #Wrapper._k
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @test_borrow_accessor_noopt1 :
+// CHECK:  [[F:%.*]] = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:  [[A:%.*]] = apply [[F]]({{.*}}) : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:  end_borrow {{.*}}
+// CHECK:  destroy_value %0
+// CHECK-LABEL: } // end sil function 'test_borrow_accessor_noopt1'
+sil [ossa] @test_borrow_accessor_noopt1 : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  %1 = begin_borrow %0
+  %2 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %3 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %4 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %5 = apply %4(%3) : $@convention(thin) (@guaranteed Klass) -> ()
+  end_borrow %1
+  destroy_value %0
+  %6 = tuple ()
+  return %6
+}
+
+// CHECK-LABEL: sil [ossa] @test_borrow_accessor_noopt2 :
+// CHECK:  [[F:%.*]] = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:  [[A:%.*]] = apply [[F]]({{.*}}) : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:  end_borrow {{.*}}
+// CHECK:  destroy_value {{.*}}
+// CHECK-LABEL: } // end sil function 'test_borrow_accessor_noopt2'
+sil [ossa] @test_borrow_accessor_noopt2 : $@convention(thin) () -> () {
+bb0:
+  %1 = function_ref @get_wrapper : $@convention(thin) () -> @owned Wrapper
+  %2 = apply %1() : $@convention(thin) () -> @owned Wrapper
+  %3 = begin_borrow %2
+  %4 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %5 = apply %4(%3) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %6 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %7 = apply %6(%5) : $@convention(thin) (@guaranteed Klass) -> ()
+  end_borrow %3
+  destroy_value %2
+  %10 = tuple ()
+  return %10
+}
+
diff --git a/test/SILOptimizer/devirt_default_witness_method.sil b/test/SILOptimizer/devirt_default_witness_method.sil
index 76aa41f5fad86..10bb2603cdf1e 100644
--- a/test/SILOptimizer/devirt_default_witness_method.sil
+++ b/test/SILOptimizer/devirt_default_witness_method.sil
@@ -43,7 +43,7 @@ public protocol ResilientProtocolWithGeneric {
   func defaultB<T: Q>(_: T)
 }
 
-sil @defaultB : $@convention(witness_method: ResilientProtocolWithGeneric) <Self where Self : ResilientProtocolWithGeneric><T where T : Q> (@in T, @in_guaranteed Self) -> () {
+sil @defaultB : $@convention(witness_method: ResilientProtocolWithGeneric) <Self where Self : ResilientProtocolWithGeneric><T where T : Q> (@in_guaranteed T, @in_guaranteed Self) -> () {
 bb0(%0 : $*T, %1 : $*Self):
   %result = tuple ()
   return %result : $()
@@ -89,8 +89,8 @@ bb0(%0 : $*ConformingGenericStruct<Int>):
 
 // CHECK-LABEL: test_devirt_of_inner_generic_default_witness_method
 // CHECK:       bb0(%0 : $*ConformingGenericStruct<Int>, %1 : $*Int):
-// CHECK:       [[FN:%[0-9]+]] = function_ref @defaultB : $@convention(witness_method: ResilientProtocolWithGeneric) <τ_0_0 where τ_0_0 : ResilientProtocolWithGeneric><τ_1_0 where τ_1_0 : Q> (@in τ_1_0, @in_guaranteed τ_0_0) -> ()
-// CHECK:       [[RESULT:%[0-9]+]] = apply [[FN]]<ConformingGenericStruct<Int>, Int>(%1, %0) : $@convention(witness_method: ResilientProtocolWithGeneric) <τ_0_0 where τ_0_0 : ResilientProtocolWithGeneric><τ_1_0 where τ_1_0 : Q> (@in τ_1_0, @in_guaranteed τ_0_0) -> ()
+// CHECK:       [[FN:%[0-9]+]] = function_ref @defaultB : $@convention(witness_method: ResilientProtocolWithGeneric) <τ_0_0 where τ_0_0 : ResilientProtocolWithGeneric><τ_1_0 where τ_1_0 : Q> (@in_guaranteed τ_1_0, @in_guaranteed τ_0_0) -> ()
+// CHECK:       [[RESULT:%[0-9]+]] = apply [[FN]]<ConformingGenericStruct<Int>, Int>(%1, %0) : $@convention(witness_method: ResilientProtocolWithGeneric) <τ_0_0 where τ_0_0 : ResilientProtocolWithGeneric><τ_1_0 where τ_1_0 : Q> (@in_guaranteed τ_1_0, @in_guaranteed τ_0_0) -> ()
 // CHECK:       return [[RESULT]] : $()
 // CHECK:     }
 sil hidden @test_devirt_of_inner_generic_default_witness_method : $@convention(thin) (@in_guaranteed ConformingGenericStruct<Int>, @in Int) -> () {
diff --git a/test/SILOptimizer/devirt_default_witness_method_ownership.sil b/test/SILOptimizer/devirt_default_witness_method_ownership.sil
index ff4c5ff090485..0e382cd876f73 100644
--- a/test/SILOptimizer/devirt_default_witness_method_ownership.sil
+++ b/test/SILOptimizer/devirt_default_witness_method_ownership.sil
@@ -43,7 +43,7 @@ public protocol ResilientProtocolWithGeneric {
   func defaultB<T: Q>(_: T)
 }
 
-sil @defaultB : $@convention(witness_method: ResilientProtocolWithGeneric) <Self where Self : ResilientProtocolWithGeneric><T where T : Q> (@in T, @in_guaranteed Self) -> () {
+sil @defaultB : $@convention(witness_method: ResilientProtocolWithGeneric) <Self where Self : ResilientProtocolWithGeneric><T where T : Q> (@in_guaranteed T, @in_guaranteed Self) -> () {
 bb0(%0 : $*T, %1 : $*Self):
   %result = tuple ()
   return %result : $()
@@ -89,8 +89,8 @@ bb0(%0 : $*ConformingGenericStruct<Int>):
 
 // CHECK-LABEL: test_devirt_of_inner_generic_default_witness_method
 // CHECK:       bb0(%0 : $*ConformingGenericStruct<Int>, %1 : $*Int):
-// CHECK:       [[FN:%[0-9]+]] = function_ref @defaultB : $@convention(witness_method: ResilientProtocolWithGeneric) <τ_0_0 where τ_0_0 : ResilientProtocolWithGeneric><τ_1_0 where τ_1_0 : Q> (@in τ_1_0, @in_guaranteed τ_0_0) -> ()
-// CHECK:       [[RESULT:%[0-9]+]] = apply [[FN]]<ConformingGenericStruct<Int>, Int>(%1, %0) : $@convention(witness_method: ResilientProtocolWithGeneric) <τ_0_0 where τ_0_0 : ResilientProtocolWithGeneric><τ_1_0 where τ_1_0 : Q> (@in τ_1_0, @in_guaranteed τ_0_0) -> ()
+// CHECK:       [[FN:%[0-9]+]] = function_ref @defaultB : $@convention(witness_method: ResilientProtocolWithGeneric) <τ_0_0 where τ_0_0 : ResilientProtocolWithGeneric><τ_1_0 where τ_1_0 : Q> (@in_guaranteed τ_1_0, @in_guaranteed τ_0_0) -> ()
+// CHECK:       [[RESULT:%[0-9]+]] = apply [[FN]]<ConformingGenericStruct<Int>, Int>(%1, %0) : $@convention(witness_method: ResilientProtocolWithGeneric) <τ_0_0 where τ_0_0 : ResilientProtocolWithGeneric><τ_1_0 where τ_1_0 : Q> (@in_guaranteed τ_1_0, @in_guaranteed τ_0_0) -> ()
 // CHECK:       return [[RESULT]] : $()
 // CHECK:     }
 sil hidden [ossa] @test_devirt_of_inner_generic_default_witness_method : $@convention(thin) (@in_guaranteed ConformingGenericStruct<Int>, @in Int) -> () {
diff --git a/test/SILOptimizer/devirt_deinits.sil b/test/SILOptimizer/devirt_deinits.sil
index 4b47b1fca2e55..cdb9a8cbd124f 100644
--- a/test/SILOptimizer/devirt_deinits.sil
+++ b/test/SILOptimizer/devirt_deinits.sil
@@ -304,6 +304,34 @@ bb0(%0 : $*S1):
   return %r : $()
 }
 
+// CHECK-LABEL: sil [ossa] @test_destroyArray :
+// CHECK:         [[ZERO:%.*]] = integer_literal $Builtin.Word, 0
+// CHECK:         [[ONE:%.*]] = integer_literal $Builtin.Word, 1
+// CHECK:         [[FALSE:%.*]] = integer_literal $Builtin.Int1, 0
+// CHECK:         [[PTA:%.*]] = pointer_to_address %0 : $Builtin.RawPointer to [strict] $*S1
+// CHECK:         br bb1([[ZERO]] : $Builtin.Word)
+// CHECK:       bb1([[IV:%.*]] : $Builtin.Word):
+// CHECK:         [[CMP:%.*]] = builtin "cmp_slt_Word"([[IV]] : $Builtin.Word, %1 : $Builtin.Word)
+// CHECK:         cond_br [[CMP]], bb2, bb3
+// CHECK:       bb2:
+// CHECK:         [[ADDR:%.*]] = index_addr [[PTA]] :  $*S1, [[IV]]
+// CHECK:         [[DEINIT:%.*]] = function_ref @s1_deinit :
+// CHECK:         [[ELEMENT:%.*]] = load [take] [[ADDR]]
+// CHECK:         apply [[DEINIT]]([[ELEMENT]])
+// CHECK:         [[ADD:%.*]] = builtin "sadd_with_overflow_Word"([[IV]] : $Builtin.Word, [[ONE]] : $Builtin.Word, [[FALSE]] : $Builtin.Int1)
+// CHECK:         [[INCR:%.*]] = tuple_extract [[ADD]] : $(Builtin.Word, Builtin.Int1), 0
+// CHECK:         br bb1([[INCR]] : $Builtin.Word)
+// CHECKL       bb3:
+// CHECK:       } // end sil function 'test_destroyArray'
+sil [ossa] @test_destroyArray : $@convention(thin) (Builtin.RawPointer, Builtin.Word) -> () {
+bb0(%0 : $Builtin.RawPointer, %1 : $Builtin.Word):
+  %2 = metatype $@thin S1.Type                    // user: %10
+  %3 = builtin "destroyArray"<S1>(%2, %0, %1) : $()
+  %r = tuple ()
+  return %r
+}
+
+
 sil @s1_deinit : $@convention(method) (@owned S1) -> ()
 sil @s2_deinit : $@convention(method) (@owned S2) -> ()
 sil @s3_deinit : $@convention(method) <T> (@in S3<T>) -> ()
diff --git a/test/SILOptimizer/devirt_deinits.swift b/test/SILOptimizer/devirt_deinits.swift
index 30a972c45e7a7..6c0836a79aab7 100644
--- a/test/SILOptimizer/devirt_deinits.swift
+++ b/test/SILOptimizer/devirt_deinits.swift
@@ -51,6 +51,16 @@ struct S3: ~Copyable {
   }
 }
 
+struct S4: ~Copyable {
+  var x: Int
+
+  @inline(never)
+  deinit {
+    print(x)
+  }
+}
+
+
 enum EnumWithDeinit: ~Copyable {
   case A(Int)
   case B
@@ -136,6 +146,18 @@ func testNestedDeinit(_ s: consuming S3) {
   log("### testNestedDeinit")
 }
 
+// CHECK-LABEL: sil hidden [noinline] @$s4test0A12DestroyArrayyySryAA2S4VGF :
+// CHECK-NOT:     "destroyArray"
+// CHECK:         [[D:%.*]] = function_ref @$s4test2S4VfD :
+// CHECK:         apply [[D]]
+// CHECK-NOT:     "destroyArray"
+// CHECK:       } // end sil function '$s4test0A12DestroyArrayyySryAA2S4VGF'
+@inline(never)
+func testDestroyArray(_ p: UnsafeMutableBufferPointer<S4>) {
+  p.deinitialize()
+}
+
+
 @main
 struct Main {
   static func main() {
@@ -182,6 +204,21 @@ struct Main {
     // CHECK-OUTPUT-NEXT:  ---
     testNestedDeinit(S3())
     log("---")
+
+    let b = UnsafeMutableBufferPointer<S4>.allocate(capacity: 3)
+    for i in 0..<3 {
+      b.initializeElement(at: i, to: S4(x: i))
+    }
+
+    // CHECK-OUTPUT-LABEL: ### testDestroyArray
+    // CHECK-OUTPUT-NEXT:  0
+    // CHECK-OUTPUT-NEXT:  1
+    // CHECK-OUTPUT-NEXT:  2
+    // CHECK-OUTPUT-NEXT:  ---
+    log("### testDestroyArray")
+    testDestroyArray(b)
+    b.deallocate()
+    log("---")
   }
 }
 
diff --git a/test/SILOptimizer/devirt_speculate.swift b/test/SILOptimizer/devirt_speculate.swift
index 78b10b61fbe7e..d81c9e7cb678a 100644
--- a/test/SILOptimizer/devirt_speculate.swift
+++ b/test/SILOptimizer/devirt_speculate.swift
@@ -101,7 +101,7 @@ class Sub7 : Base {
 // YAML:   File:            {{.*}}/devirt_speculate.swift
 // YAML:   Line:            118
 // YAML:   Column:          5
-// YAML-NEXT: Function:        'testMaxNumSpeculativeTargets(_:)'
+// YAML-NEXT: Function:        '$s16devirt_speculate28testMaxNumSpeculativeTargetsyyAA4BaseCF'
 // YAML-NEXT: Args:
 // YAML-NEXT:   - String:          'Partially devirtualized call with run-time checks for '
 // YAML-NEXT:   - NumSubTypesChecked: '6'
diff --git a/test/SILOptimizer/devirt_speculative.sil b/test/SILOptimizer/devirt_speculative.sil
index efddb1bd1e5a0..e4a8b0e7a71c6 100644
--- a/test/SILOptimizer/devirt_speculative.sil
+++ b/test/SILOptimizer/devirt_speculative.sil
@@ -160,7 +160,7 @@ bb0(%0 : $S1):
   return %1 : $()
 }
 
-sil hidden [thunk] [always_inline] @$S4main2S2C8mayThrowyyKF : $@convention(method) (@guaranteed S2) -> @error any Error {
+sil hidden [thunk] [heuristic_always_inline] @$S4main2S2C8mayThrowyyKF : $@convention(method) (@guaranteed S2) -> @error any Error {
 bb0(%0 : $S2):
   %1 = tuple ()
   return %1 : $()
diff --git a/test/SILOptimizer/devirt_static_witness_method.sil b/test/SILOptimizer/devirt_static_witness_method.sil
index a016e54f697f4..23c32a2856fd2 100644
--- a/test/SILOptimizer/devirt_static_witness_method.sil
+++ b/test/SILOptimizer/devirt_static_witness_method.sil
@@ -1,4 +1,5 @@
 // RUN: %target-sil-opt -enable-sil-verify-all %s -devirtualizer -sil-combine | %FileCheck %s
+
 sil_stage canonical
 
 import Builtin
@@ -18,13 +19,13 @@ struct S<T> : CanAdd {
 func +<T>(lhs: S<T>, rhs: S<T>) -> S<T>
 
 
-sil hidden [transparent] [thunk] @operator_plus_static_non_generic_witness_for_S : $@convention(witness_method: CanAdd) <T> (@in S<T>, @in S<T>, @thick S<T>.Type) -> @out S<T> {
+sil hidden [transparent] [thunk] @operator_plus_static_non_generic_witness_for_S : $@convention(witness_method: CanAdd) <T> (@in_guaranteed S<T>, @in_guaranteed S<T>, @thick S<T>.Type) -> @out S<T> {
 bb0(%0 : $*S<T>, %1 : $*S<T>, %2 : $*S<T>, %3 : $@thick S<T>.Type) :
   %17 = tuple ()
   return %17 : $()
 }
 
-sil hidden [transparent] [thunk] @operator_plus_static_non_generic_witness : $@convention(witness_method: CanAdd) (@in Int64, @in Int64, @thick Int64.Type) -> @out Int64 {
+sil hidden [transparent] [thunk] @operator_plus_static_non_generic_witness : $@convention(witness_method: CanAdd) (@in_guaranteed Int64, @in_guaranteed Int64, @thick Int64.Type) -> @out Int64 {
 bb0(%0 : $*Int64, %1 : $*Int64, %2 : $*Int64, %3 : $@thick Int64.Type):
   %4 = struct_element_addr %1 : $*Int64, #Int64._value
   %5 = load %4 : $*Builtin.Int64
@@ -44,12 +45,12 @@ bb0(%0 : $*Int64, %1 : $*Int64, %2 : $*Int64, %3 : $@thick Int64.Type):
 // Test that this partial application of a function reference referring to static non generic witness does not crash the IRGen.
 // Such code may be produced e.g. when users refer to global operators defined on builtin types.
 // CHECK-LABEL: sil hidden @test_partial_apply_of_static_witness
-sil hidden @test_partial_apply_of_static_witness : $@convention(thin) () -> @callee_owned (@in Int64, @in Int64) -> @out Int64 {
+sil hidden @test_partial_apply_of_static_witness : $@convention(thin) () -> @callee_owned (@in_guaranteed Int64, @in_guaranteed Int64) -> @out Int64 {
 bb0:
   %1 = metatype $@thick Int64.Type
-  %2 = function_ref @operator_plus_static_non_generic_witness : $@convention(witness_method: CanAdd) (@in Int64, @in Int64, @thick Int64.Type) -> @out Int64
-  %3 = partial_apply %2(%1) : $@convention(witness_method: CanAdd) (@in Int64, @in Int64, @thick Int64.Type) -> @out Int64
-  return %3 : $@callee_owned (@in Int64, @in Int64) -> @out Int64
+  %2 = function_ref @operator_plus_static_non_generic_witness : $@convention(witness_method: CanAdd) (@in_guaranteed Int64, @in_guaranteed Int64, @thick Int64.Type) -> @out Int64
+  %3 = partial_apply %2(%1) : $@convention(witness_method: CanAdd) (@in_guaranteed Int64, @in_guaranteed Int64, @thick Int64.Type) -> @out Int64
+  return %3 : $@callee_owned (@in_guaranteed Int64, @in_guaranteed Int64) -> @out Int64
 }
 
 // Test that this partial application of witness_method can be devirtualized.
@@ -58,12 +59,12 @@ bb0:
 // CHECK: function_ref @operator_plus_static_non_generic_witness_for_S
 // CHECK: partial_apply
 // CHECK: return
-sil hidden @test_devirt_of_partial_apply_of_witness_method : $@convention(thin) () -> @callee_owned (@in S<Int64>, @in S<Int64>) -> @out S<Int64> {
+sil hidden @test_devirt_of_partial_apply_of_witness_method : $@convention(thin) () -> @callee_owned (@in_guaranteed S<Int64>, @in_guaranteed S<Int64>) -> @out S<Int64> {
 bb0:
   %1 = metatype $@thick S<Int64>.Type
-  %2 = witness_method $S<Int64>, #CanAdd."+" : $@convention(witness_method: CanAdd) <τ_0_0 where τ_0_0 : CanAdd> (@in τ_0_0, @in τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %3 = partial_apply %2<S<Int64>>(%1) : $@convention(witness_method: CanAdd) <τ_0_0 where τ_0_0 : CanAdd> (@in τ_0_0, @in τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
-  return %3 : $@callee_owned (@in S<Int64>, @in S<Int64>) -> @out S<Int64>
+  %2 = witness_method $S<Int64>, #CanAdd."+" : $@convention(witness_method: CanAdd) <τ_0_0 where τ_0_0 : CanAdd> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
+  %3 = partial_apply %2<S<Int64>>(%1) : $@convention(witness_method: CanAdd) <τ_0_0 where τ_0_0 : CanAdd> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
+  return %3 : $@callee_owned (@in_guaranteed S<Int64>, @in_guaranteed S<Int64>) -> @out S<Int64>
 }
 
 // Test that this application of witness_method can be devirtualized.
@@ -72,12 +73,12 @@ bb0:
 // CHECK: function_ref @operator_plus_static_non_generic_witness_for_S
 // CHECK: apply
 // CHECK: return
-sil hidden @test_devirt_of_apply_of_witness_method : $@convention(thin) (@in S<Int64>) -> S<Int64> {
+sil hidden @test_devirt_of_apply_of_witness_method : $@convention(thin) (@in_guaranteed S<Int64>) -> S<Int64> {
 bb0(%0 : $*S<Int64>):
   %1 = alloc_stack $S<Int64>
   %5 = metatype $@thick S<Int64>.Type
-  %6 = witness_method $S<Int64>, #CanAdd."+" : $@convention(witness_method: CanAdd) <τ_0_0 where τ_0_0 : CanAdd> (@in τ_0_0, @in τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %7 = apply %6<S<Int64>>(%1, %0, %0, %5) : $@convention(witness_method: CanAdd) <τ_0_0 where τ_0_0 : CanAdd> (@in τ_0_0, @in τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
+  %6 = witness_method $S<Int64>, #CanAdd."+" : $@convention(witness_method: CanAdd) <τ_0_0 where τ_0_0 : CanAdd> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
+  %7 = apply %6<S<Int64>>(%1, %0, %0, %5) : $@convention(witness_method: CanAdd) <τ_0_0 where τ_0_0 : CanAdd> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
   %8 = load %1: $*S<Int64>
   dealloc_stack %1 : $*S<Int64>
   return %8 : $S<Int64>
diff --git a/test/SILOptimizer/devirt_witness_method_empty_conformance.swift b/test/SILOptimizer/devirt_witness_method_empty_conformance.swift
index e8ea8e7959487..cbb8e66cc8eca 100644
--- a/test/SILOptimizer/devirt_witness_method_empty_conformance.swift
+++ b/test/SILOptimizer/devirt_witness_method_empty_conformance.swift
@@ -76,7 +76,7 @@ extension ApplyRegStruct {
         from space: PublicEnum, transform: RegStruct
     ) {
         transform.funcInStructAndProtAndExt(.case2, space: space) {
-// CHECK-LABEL: define hidden swiftcc void @"$sSa39devirt_witness_method_empty_conformanceAA12PublicStructVRszlE14applyTransformyyF"(ptr nocapture {{.*}}swiftself dereferenceable
+// CHECK-LABEL: define hidden swiftcc void @"$sSa39devirt_witness_method_empty_conformanceAA12PublicStructVRszlE14applyTransformyyF"(ptr{{( nocapture)?}} {{.*}}swiftself{{( captures\(none\))?}} dereferenceable
 // CHECK-NEXT: entry
 // CHECK-NEXT: ret void
             applyTransform()
diff --git a/test/SILOptimizer/devirtualize.sil b/test/SILOptimizer/devirtualize.sil
index ea1404073dcae..66c18afa9c50e 100644
--- a/test/SILOptimizer/devirtualize.sil
+++ b/test/SILOptimizer/devirtualize.sil
@@ -137,7 +137,7 @@ bb0(%0 : $@thick C.Type):
 // YAML:        File:            {{.*}}/devirtualize.sil
 // YAML:        Line:            127
 // YAML:        Column:          8
-// YAML-NEXT: Function:        'caller(_:)'
+// YAML-NEXT: Function:        _TF4metaP33_7026FC13D35FB9700BACF693F51A99016callerFMCS_P33_7026FC13D35FB9700BACF693F51A99011CT_
 // YAML-NEXT: Args:
 // YAML-NEXT:   - String:          'Devirtualized call to class method '
 // YAML-NEXT:   - Method:          '"static meta.B.foo(_:)"'
diff --git a/test/SILOptimizer/devirtualize_coroutine_accessors.sil b/test/SILOptimizer/devirtualize_coroutine_accessors.sil
index a8ba4bc806a2e..1e7dfecff9415 100644
--- a/test/SILOptimizer/devirtualize_coroutine_accessors.sil
+++ b/test/SILOptimizer/devirtualize_coroutine_accessors.sil
@@ -1,5 +1,6 @@
 // RUN: %target-sil-opt \
 // RUN:     -devirtualizer \
+// RUN:     -enable-callee-allocated-coro-abi\
 // RUN:     %s \
 // RUN:     -enable-sil-verify-all \
 // RUN:     -enable-experimental-feature CoroutineAccessors \
diff --git a/test/SILOptimizer/devirtualize_ownership.sil b/test/SILOptimizer/devirtualize_ownership.sil
index 9003178eed2c2..642fe4202b33b 100644
--- a/test/SILOptimizer/devirtualize_ownership.sil
+++ b/test/SILOptimizer/devirtualize_ownership.sil
@@ -138,7 +138,7 @@ bb0(%0 : $@thick C.Type):
 // YAML:        File:            {{.*}}/devirtualize_ownership.sil
 // YAML:        Line:            128
 // YAML:        Column:          8
-// YAML-NEXT: Function:        'caller(_:)'
+// YAML-NEXT: Function:        _TF4metaP33_7026FC13D35FB9700BACF693F51A99016callerFMCS_P33_7026FC13D35FB9700BACF693F51A99011CT_
 // YAML-NEXT: Args:
 // YAML-NEXT:   - String:          'Devirtualized call to class method '
 // YAML-NEXT:   - Method:          '"static meta.B.foo(_:)"'
diff --git a/test/SILOptimizer/diagnose_unreachable.swift b/test/SILOptimizer/diagnose_unreachable.swift
index ee8cbd9fe24c9..36e81087202c1 100644
--- a/test/SILOptimizer/diagnose_unreachable.swift
+++ b/test/SILOptimizer/diagnose_unreachable.swift
@@ -507,7 +507,7 @@ struct OuterStruct {
 }
 
 @dynamicMemberLookup
-public enum DynamicLookupEnum {
+enum DynamicLookupEnum {
     subscript<T>(dynamicMember keyPath: KeyPath<OuterStruct, T>) -> T {
         fatalError()
     }
diff --git a/test/SILOptimizer/diagnostic_constant_propagation_floats_x86.swift b/test/SILOptimizer/diagnostic_constant_propagation_floats_x86.swift
index 6411c9aa5b972..8cdcc90e4aa37 100644
--- a/test/SILOptimizer/diagnostic_constant_propagation_floats_x86.swift
+++ b/test/SILOptimizer/diagnostic_constant_propagation_floats_x86.swift
@@ -1,7 +1,9 @@
 // RUN: %target-swift-frontend -emit-sil -primary-file %s -o /dev/null -verify
 //
 // REQUIRES: CPU=i386 || CPU=x86_64
-// UNSUPPORTED: OS=windows-msvc
+//
+// Windows and Android do not expose Float80.
+// UNSUPPORTED: OS=windows-msvc, OS=linux-android
 //
 // These are tests for diagnostics produced by constant propagation pass
 // on floating-point operations that are specific to x86 architectures,
diff --git a/test/SILOptimizer/disable-copy-propagation-frontend-flag.swift b/test/SILOptimizer/disable-copy-propagation-frontend-flag.swift
index 91ed913dd4f91..194db5aa3c26f 100644
--- a/test/SILOptimizer/disable-copy-propagation-frontend-flag.swift
+++ b/test/SILOptimizer/disable-copy-propagation-frontend-flag.swift
@@ -49,7 +49,7 @@
 
 // RUN: %target-swift-frontend %s \
 // RUN:     -O \
-// RUN:     -enable-copy-propagation=true \
+// RUN:     -enable-copy-propagation=optimizing \
 // RUN:     -Xllvm -sil-print-pass-name \
 // RUN:     -emit-ir \
 // RUN:     -o /dev/null \
@@ -57,7 +57,7 @@
 
 // RUN: %target-swift-frontend %s \
 // RUN:     -O \
-// RUN:     -enable-copy-propagation=true \
+// RUN:     -enable-copy-propagation=optimizing \
 // RUN:     -enable-destroy-hoisting=false \
 // RUN:     -Xllvm -sil-print-pass-name \
 // RUN:     -emit-ir \
@@ -66,7 +66,7 @@
 
 // RUN: %target-swift-frontend %s \
 // RUN:     -O \
-// RUN:     -enable-copy-propagation=true \
+// RUN:     -enable-copy-propagation=optimizing \
 // RUN:     -enable-destroy-hoisting=true \
 // RUN:     -Xllvm -sil-print-pass-name \
 // RUN:     -emit-ir \
diff --git a/test/SILOptimizer/drop_deinit_opt.sil b/test/SILOptimizer/drop_deinit_opt.sil
new file mode 100644
index 0000000000000..1fe18325c3286
--- /dev/null
+++ b/test/SILOptimizer/drop_deinit_opt.sil
@@ -0,0 +1,47 @@
+// RUN: %target-sil-opt %s -early-inline -mem2reg | %FileCheck %s
+
+import Swift
+import Builtin
+
+struct FileDescriptor : ~Copyable {
+  @_hasStorage private var fd: Int { get set }
+  init(_ fd: Int)
+  deinit
+}
+
+sil hidden [ossa] @fd_close : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  debug_value %0, let, name "fd", argno 1
+  %2 = tuple ()
+  return %2
+}
+
+// CHECK-LABEL: sil hidden [ossa] @fd_deinit1 :
+// CHECK: drop_deinit
+// CHECK-LABEL: } // end sil function 'fd_deinit1'
+sil hidden [ossa] @fd_deinit1 : $@convention(method) (@owned FileDescriptor) -> () {
+bb0(%0 : @owned $FileDescriptor):
+  %1 = alloc_stack $FileDescriptor, let, name "self", argno 1
+  store %0 to [init] %1
+  %3 = drop_deinit %1
+  %6 = struct_element_addr %3, #FileDescriptor.fd
+  %7 = load [trivial] %6
+  %9 = function_ref @fd_close : $@convention(thin) (Int) -> ()
+  %10 = apply %9(%7) : $@convention(thin) (Int) -> ()
+  dealloc_stack %1
+  %12 = tuple ()
+  return %12
+}
+
+// CHECK-LABEL: sil hidden [ossa] @fd_deinit2 :
+// CHECK: end_lifetime
+// CHECK-LABEL: } // end sil function 'fd_deinit2'
+sil hidden [ossa] @fd_deinit2 : $@convention(method) (@owned FileDescriptor) -> () {
+bb0(%0 : @owned $FileDescriptor):
+  %3 = drop_deinit %0
+  %6 = destructure_struct %3
+  %9 = function_ref @fd_close : $@convention(thin) (Int) -> ()
+  %10 = apply %9(%6) : $@convention(thin) (Int) -> ()
+  %12 = tuple ()
+  return %12
+}
diff --git a/test/SILOptimizer/eager_specialize.sil b/test/SILOptimizer/eager_specialize.sil
index 3f4a290d927f6..74b80968ee0d8 100644
--- a/test/SILOptimizer/eager_specialize.sil
+++ b/test/SILOptimizer/eager_specialize.sil
@@ -698,7 +698,7 @@ bb0(%0 : $*Self, %1 : $*Self, %2 : $@thick Self.Type):
 
 // Check that a specialization for _Trivial(32) uses direct loads and stores
 // instead of value witness functions to load and store the value of a generic type.
-// CHECK-IRGEN-LABEL: define linkonce_odr hidden swiftcc void @"$s16eager_specialize18copyValueAndReturn_1sxx_xztlFxxxRlze31_lIetilr_Tp5"(ptr noalias nocapture sret(i32) %0, ptr noalias nocapture dereferenceable(4) %1, ptr nocapture dereferenceable(4) %2, ptr %S
+// CHECK-IRGEN-LABEL: define linkonce_odr hidden swiftcc void @"$s16eager_specialize18copyValueAndReturn_1sxx_xztlFxxxRlze31_lIetilr_Tp5"(ptr noalias{{( nocapture)?}} sret(i32){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(4) %1, ptr {{(nocapture|captures\(none\))}} dereferenceable(4) %2, ptr %S
 // CHECK-IRGEN: entry:
 // CHECK-IRGEN:       %3 = load i32, ptr %2
 // CHECK-IRGEN-NEXT:  store i32 %3, ptr %0
@@ -707,7 +707,7 @@ bb0(%0 : $*Self, %1 : $*Self, %2 : $@thick Self.Type):
 
 // Check that a specialization for _Trivial(64) uses direct loads and stores
 // instead of value witness functions to load and store the value of a generic type.
-// CHECK-IRGEN-LABEL: define linkonce_odr hidden swiftcc void @"$s16eager_specialize18copyValueAndReturn_1sxx_xztlFxxxRlze63_lIetilr_Tp5"(ptr noalias nocapture sret(i64) %0, ptr noalias nocapture dereferenceable(8) %1, ptr nocapture dereferenceable(8) %2, ptr %S
+// CHECK-IRGEN-LABEL: define linkonce_odr hidden swiftcc void @"$s16eager_specialize18copyValueAndReturn_1sxx_xztlFxxxRlze63_lIetilr_Tp5"(ptr noalias{{( nocapture)?}} sret(i64){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(8) %1, ptr {{(nocapture|captures\(none\))}} dereferenceable(8) %2, ptr %S
 // CHECK-IRGEN: entry:
 // CHECK-IRGEN:        %3 = load i64, ptr %2
 // CHECK-IRGEN-NEXT:   store i64 %3, ptr %0
diff --git a/test/SILOptimizer/eager_specialize_ossa.sil b/test/SILOptimizer/eager_specialize_ossa.sil
index 2ac721d8a6d96..92cd9a1d06dc4 100644
--- a/test/SILOptimizer/eager_specialize_ossa.sil
+++ b/test/SILOptimizer/eager_specialize_ossa.sil
@@ -886,7 +886,7 @@ bb0(%0 : $*Self, %1 : $*Self, %2 : $@thick Self.Type):
 
 // Check that a specialization for _Trivial(32) uses direct loads and stores
 // instead of value witness functions to load and store the value of a generic type.
-// CHECK-IRGEN-LABEL: define linkonce_odr hidden swiftcc void @"$s16eager_specialize18copyValueAndReturn_1sxx_xztlFxxxRlze31_lIetilr_Tp5"(ptr noalias nocapture sret(i32) %0, ptr noalias nocapture dereferenceable(4) %1, ptr nocapture dereferenceable(4) %2, ptr %S
+// CHECK-IRGEN-LABEL: define linkonce_odr hidden swiftcc void @"$s16eager_specialize18copyValueAndReturn_1sxx_xztlFxxxRlze31_lIetilr_Tp5"(ptr noalias{{( nocapture)?}} sret(i32){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(4) %1, ptr {{(nocapture|captures\(none\))}} dereferenceable(4) %2, ptr %S
 // CHECK-IRGEN: entry:
 // CHECK-IRGEN:       %3 = load i32, ptr %2
 // CHECK-IRGEN-NEXT:  store i32 %3, ptr %0
@@ -895,7 +895,7 @@ bb0(%0 : $*Self, %1 : $*Self, %2 : $@thick Self.Type):
 
 // Check that a specialization for _Trivial(64) uses direct loads and stores
 // instead of value witness functions to load and store the value of a generic type.
-// CHECK-IRGEN-LABEL: define linkonce_odr hidden swiftcc void @"$s16eager_specialize18copyValueAndReturn_1sxx_xztlFxxxRlze63_lIetilr_Tp5"(ptr noalias nocapture sret(i64) %0, ptr noalias nocapture dereferenceable(8) %1, ptr nocapture dereferenceable(8) %2, ptr %S
+// CHECK-IRGEN-LABEL: define linkonce_odr hidden swiftcc void @"$s16eager_specialize18copyValueAndReturn_1sxx_xztlFxxxRlze63_lIetilr_Tp5"(ptr noalias{{( nocapture)?}} sret(i64){{( captures\(none\))?}} %0, ptr noalias {{(nocapture|captures\(none\))}} dereferenceable(8) %1, ptr {{(nocapture|captures\(none\))}} dereferenceable(8) %2, ptr %S
 // CHECK-IRGEN: entry:
 // CHECK-IRGEN:        %3 = load i64, ptr %2
 // CHECK-IRGEN-NEXT:   store i64 %3, ptr %0
diff --git a/test/SILOptimizer/enum-comparison.swift b/test/SILOptimizer/enum-comparison.swift
new file mode 100644
index 0000000000000..37a90c6d15c87
--- /dev/null
+++ b/test/SILOptimizer/enum-comparison.swift
@@ -0,0 +1,144 @@
+// RUN: %empty-directory(%t) 
+// RUN: %target-build-swift -O -module-name=test %s -o %t/a.out
+// RUN: %target-build-swift -O -module-name=test %s -emit-ir | %FileCheck %s
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s --check-prefix=OUT
+
+// REQUIRES: executable_test,optimized_stdlib
+// REQUIRES: PTRSIZE=64
+
+enum E: String {
+  case a, b, c, long_case_name_for_testing, d, e
+}
+
+// CHECK-LABEL: define {{.*}} i1 @"$s4test9compareeqySbAA1EO_ADtF"(i8 %0, i8 %1)
+// CHECK:         %2 = icmp eq i8 %0, %1
+// CHECK-NEXT:    ret i1 %2
+@inline(never)
+func compareeq(_ a: E, _ b: E) -> Bool {
+  return a == b
+}
+
+// CHECK-LABEL: define {{.*}} i1 @"$s4test9compareneySbAA1EO_ADtF"(i8 %0, i8 %1)
+// CHECK:         %2 = icmp ne i8 %0, %1
+// CHECK-NEXT:    ret i1 %2
+@inline(never)
+func comparene(_ a: E, _ b: E) -> Bool {
+  return a != b
+}
+
+enum LargeEnum: Equatable {
+  case a1, a2, a3, a4, a5, a6, a7, a8, a9
+  case b1, b2, b3, b4, b5, b6, b7, b8, b9
+  case c1, c2, c3, c4, c5, c6, c7, c8, c9
+  case d1, d2, d3, d4, d5, d6, d7, d8, d9
+  case e1(Int64), e2(Int64), e3(Int64), e4(Int64), e5(Int64), e6(Int64), e7(Int64), e8(Int64), e9(Int64)
+  case f1, f2, f3, f4, f5, f6, f7, f8, f9
+  case g1, g2, g3, g4, g5, g6, g7, g8, g9
+}
+
+// CHECK-LABEL: define {{.*}} i1 @"$s4test8compare1ySbAA9LargeEnumOF"(i64 %0, i8 %1)
+// CHECK:       entry:
+// CHECK-NEXT:    icmp
+// CHECK-NEXT:    icmp
+// CHECK-NEXT:    {{(and|select)}}
+// CHECK-NEXT:    ret
+@inline(never)
+func compare1(_ x: LargeEnum) -> Bool {
+  return x == .b2
+}
+
+// CHECK-LABEL: define {{.*}} i1 @"$s4test8compare2ySbAA9LargeEnumOF"(i64 %0, i8 %1)
+// CHECK:       entry:
+// CHECK-NEXT:    icmp
+// CHECK-NEXT:    icmp
+// CHECK-NEXT:    {{(and|select)}}
+// CHECK-NEXT:    ret
+@inline(never)
+func compare2(_ x: LargeEnum) -> Bool {
+  return .f2 == x
+}
+
+// CHECK-LABEL: define {{.*}} i1 @"$s4test8compare3ySbAA9LargeEnumOF"(i64 %0, i8 %1)
+// CHECK:       entry:
+// CHECK-NEXT:    icmp
+// CHECK-NEXT:    icmp
+// CHECK-NEXT:    {{(and|select)}}
+// CHECK-NEXT:    ret
+@inline(never)
+func compare3(_ x: LargeEnum) -> Bool {
+  return .e2(27) == x
+}
+
+// CHECK-LABEL: define {{.*}} i1 @"$s4test8compare4ySbAA9LargeEnumOF"(i64 %0, i8 %1)
+// CHECK:       entry:
+// CHECK-NEXT:    icmp
+// CHECK-NEXT:    icmp
+// CHECK-NEXT:    {{(and|select)}}
+// CHECK-NEXT:    ret
+@inline(never)
+func compare4(_ x: LargeEnum) -> Bool {
+  return x == .e3(28)
+}
+
+enum CustomRawValue: RawRepresentable {
+  case a, b, c
+
+  init(rawValue: Int) {
+    self = .a
+  }
+
+  @inline(never)
+  var rawValue: Int {
+    print(0)
+    return 0
+  }
+}
+
+// CHECK-LABEL: define {{.*}} i1 @"$s4test8compare5ySbAA14CustomRawValueOF"(i8 %0)
+// CHECK:       entry:
+// CHECK-NEXT:    call
+@inline(never)
+func compare5(_ x: CustomRawValue) -> Bool {
+  return x == .b
+}
+
+// OUT: 1: false
+print("1: \(compareeq(.c, .long_case_name_for_testing))")
+
+// OUT: 2: true
+print("2: \(compareeq(.c, .c))")
+
+// OUT: 3: true
+print("3: \(comparene(.c, .long_case_name_for_testing))")
+
+// OUT: 4: false
+print("4: \(comparene(.c, .c))")
+
+// OUT: 5: false
+print("5: \(compare1(.b1))")
+
+// OUT: 6: true
+print("6: \(compare1(.b2))")
+
+// OUT: 7: false
+print("7: \(compare2(.b1))")
+
+// OUT: 8: true
+print("8: \(compare2(.f2))")
+
+// OUT: 9: true
+print("9: \(compare3(.e2(27)))")
+
+// OUT: 10: false
+print("10: \(compare3(.e2(28)))")
+
+// OUT: 11: true
+print("11: \(compare4(.e3(28)))")
+
+// OUT: 12: false
+print("12: \(compare4(.e3(27)))")
+
+// OUT: 13: true
+print("13: \(compare5(.a))")
+
diff --git a/test/SILOptimizer/enum_payload_modification_opt.swift b/test/SILOptimizer/enum_payload_modification_opt.swift
index fdb3a500c5ad4..52cf7038237b6 100644
--- a/test/SILOptimizer/enum_payload_modification_opt.swift
+++ b/test/SILOptimizer/enum_payload_modification_opt.swift
@@ -3,7 +3,6 @@
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test,swift_stdlib_no_asserts,optimized_stdlib
-// REQUIRES: rdar89260664
 
 final class Storage {
   var v : Int
diff --git a/test/SILOptimizer/escape_analysis_invalidate.sil b/test/SILOptimizer/escape_analysis_invalidate.sil
index 2125b5374c54a..1fbadb022939c 100644
--- a/test/SILOptimizer/escape_analysis_invalidate.sil
+++ b/test/SILOptimizer/escape_analysis_invalidate.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types %s -compute-escape-effects -compute-side-effects -temp-rvalue-opt -enable-sil-verify-all -wmo | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types %s -compute-escape-effects -compute-side-effects -temp-rvalue-elimination -enable-sil-verify-all -wmo | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 
diff --git a/test/SILOptimizer/escape_info.sil b/test/SILOptimizer/escape_info.sil
index 2230c83e8e223..285c7d5dfd7f6 100644
--- a/test/SILOptimizer/escape_info.sil
+++ b/test/SILOptimizer/escape_info.sil
@@ -1510,3 +1510,21 @@ bb0:
   dealloc_stack %0 : $*X
   return %4 : $Builtin.RawPointer
 }
+
+// CHECK-LABEL: Escape information for test_vector_base_addr_escaping:
+// CHECK:       return[]:   %1 = alloc_ref $X
+// CHECK:       End function test_vector_base_addr_escaping
+sil @test_vector_base_addr_escaping : $@convention(thin) () -> @owned X {
+bb0:
+  %0 = alloc_stack $Builtin.FixedArray<10, X>
+  %1 = alloc_ref $X
+  %2 = vector_base_addr %0
+  %3 = integer_literal $Builtin.Int64, 1
+  %4 = index_addr %2, %3
+  store %1 to %4
+  %6 = vector_base_addr %0
+  %7 = index_addr %6, %3
+  %8 = load %4
+  dealloc_stack %0
+  return %8
+}
diff --git a/test/SILOptimizer/exclusivity_static_diagnostics.sil b/test/SILOptimizer/exclusivity_static_diagnostics.sil
index cba819eeaffce..c96ed8497f453 100644
--- a/test/SILOptimizer/exclusivity_static_diagnostics.sil
+++ b/test/SILOptimizer/exclusivity_static_diagnostics.sil
@@ -1493,7 +1493,7 @@ bb0(%0 : $*Builtin.Int64, %1 : $*TestDynamic):
 }
 
 // Dictionary.subscript.modify
-sil [serialized] [always_inline] @$sSD_7defaultq_x_q_yXKtciM : $@yield_once @convention(method) <τ_0_0, τ_0_1 where τ_0_0 : Hashable> (@in_guaranteed τ_0_0, @noescape @callee_guaranteed () -> @out τ_0_1, @inout Dictionary<τ_0_0, τ_0_1>) -> @yields @inout τ_0_1
+sil [serialized] [heuristic_always_inline] @$sSD_7defaultq_x_q_yXKtciM : $@yield_once @convention(method) <τ_0_0, τ_0_1 where τ_0_0 : Hashable> (@in_guaranteed τ_0_0, @noescape @callee_guaranteed () -> @out τ_0_1, @inout Dictionary<τ_0_0, τ_0_1>) -> @yields @inout τ_0_1
 
 // -----------------------------------------------------------------------------
 // testBeginApplyOfClosure: DiagnoseStaticExclusivity must consider
diff --git a/test/SILOptimizer/exclusivity_static_diagnostics.swift b/test/SILOptimizer/exclusivity_static_diagnostics.swift
index 646858a122e00..0fc1f2c9ee46c 100644
--- a/test/SILOptimizer/exclusivity_static_diagnostics.swift
+++ b/test/SILOptimizer/exclusivity_static_diagnostics.swift
@@ -263,12 +263,9 @@ func callsClosureLiteralImmediately() {
 
 func callsStoredClosureLiteral() {
   var i = 7;
-  let c = { (p: inout Int) in i}
+  let c = { (p: inout Int) in i} // expected-note {{conflicting access is here}}
 
-  // Closure literals that are stored and later called are treated as escaping
-  // We don't expect a static exclusivity diagnostic here, but the issue
-  // will be caught at run time
-  _ = c(&i) // no-error
+  _ = c(&i) // expected-error {{overlapping accesses to 'i', but modification requires exclusive access; consider copying to a local variable}}
 }
 
 
diff --git a/test/SILOptimizer/existential_specializer_indirect_class.sil b/test/SILOptimizer/existential_specializer_indirect_class.sil
index 12e0213570533..d3d9da67596e3 100644
--- a/test/SILOptimizer/existential_specializer_indirect_class.sil
+++ b/test/SILOptimizer/existential_specializer_indirect_class.sil
@@ -10,7 +10,7 @@ protocol ClassProtocol: AnyObject { func method() }
 
 class C: ClassProtocol { func method() {} }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @test_indirect_class_protocol : $@convention(thin) (@in any ClassProtocol) -> ()
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @test_indirect_class_protocol : $@convention(thin) (@in any ClassProtocol) -> ()
 sil [noinline] @test_indirect_class_protocol : $@convention(thin) (@in ClassProtocol) -> () {
 // CHECK: bb0(%0 : $*any ClassProtocol):
 bb0(%0 : $*ClassProtocol):
diff --git a/test/SILOptimizer/existential_specializer_soletype.sil b/test/SILOptimizer/existential_specializer_soletype.sil
index 814f35662985e..9add504b573e9 100644
--- a/test/SILOptimizer/existential_specializer_soletype.sil
+++ b/test/SILOptimizer/existential_specializer_soletype.sil
@@ -194,7 +194,7 @@ public struct S : P {
 }
 
 // Check the thunk.
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @$s6test2_6storePyyAA1P_p_AaC_pztF : $@convention(thin) (@in any P, @inout any P) -> () {
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s6test2_6storePyyAA1P_p_AaC_pztF : $@convention(thin) (@in any P, @inout any P) -> () {
 // CHECK: bb0(%0 : $*any P, %1 : $*any P):
 // CHECK: [[F:%.*]] = function_ref @$s6test2_6storePyyAA1P_p_AaC_pztFTf4en_n : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@in τ_0_0, @inout any P) -> ()
 // CHECK: [[ADR:%.*]] = open_existential_addr mutable_access %0 : $*any P to $*@opened([[TY:".*"]], any P) Self
@@ -274,7 +274,7 @@ sil_witness_table S: P module test {}
 // Test an existential in_guaranteed argument.
 //===----------------------------------------------------------------------===//
 
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @$s6test3_6storePyyAA1P_pz_AaC_pztF : $@convention(thin) (@in_guaranteed any P, @inout any P) -> () {
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s6test3_6storePyyAA1P_pz_AaC_pztF : $@convention(thin) (@in_guaranteed any P, @inout any P) -> () {
 // CHECK: bb0(%0 : $*any P, %1 : $*any P):
 // CHECK: [[F:%.*]] = function_ref @$s6test3_6storePyyAA1P_pz_AaC_pztFTf4en_n : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0, @inout any P) -> ()
 // CHECK: [[ADR:%.*]] = open_existential_addr immutable_access %0 : $*any P to $*@opened("{{.*}}", any P) Self
diff --git a/test/SILOptimizer/existential_specializer_soletype_opaque_addrlowered.sil b/test/SILOptimizer/existential_specializer_soletype_opaque_addrlowered.sil
index dd8e8f5db6e8b..048ed182a8f7a 100644
--- a/test/SILOptimizer/existential_specializer_soletype_opaque_addrlowered.sil
+++ b/test/SILOptimizer/existential_specializer_soletype_opaque_addrlowered.sil
@@ -16,7 +16,7 @@ public struct S : P {
 
 // Verify that the opened existential type used in thunk building is properly
 // address lowered even though it has an OpaqueValueTypeLowering.
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @$s6test2_6storePyyAA1P_p_AaC_pztF : {{.*}} {
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s6test2_6storePyyAA1P_p_AaC_pztF : {{.*}} {
 // CHECK:       {{bb[0-9]+}}([[IN_ADDR:%[^,]+]] : $*any P, [[OUT_ADDR:%[^,]+]] : $*any P):
 // CHECK:         [[OPENED_IN_ADDR:%[^,]+]] = open_existential_addr mutable_access [[IN_ADDR]] : $*any P to $*@opened([[UUID:".*"]], any P) Self 
 // CHECK:         [[OPENED_OUT_ADDR:%[^,]+]] = alloc_stack $@opened([[UUID]], any P) Self 
diff --git a/test/SILOptimizer/existential_transform_respecialize.sil b/test/SILOptimizer/existential_transform_respecialize.sil
index 9a495a895b06e..8905e006a1d01 100644
--- a/test/SILOptimizer/existential_transform_respecialize.sil
+++ b/test/SILOptimizer/existential_transform_respecialize.sil
@@ -44,7 +44,7 @@ sil [noinline] @$s1t9SomeClassC3fooSiyF : $@convention(method) (@guaranteed Some
 // The original "wrapFoo" function prior to existential specialization.
 //
 // This will be replaced with a thunk by existential specialization.
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @$s1t7wrapFoo1a1bSi_SitAA12SomeProtocol_p_AaE_ptF : $@convention(thin) (@guaranteed any SomeProtocol, @guaranteed any SomeProtocol) -> (Int, Int) {
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s1t7wrapFoo1a1bSi_SitAA12SomeProtocol_p_AaE_ptF : $@convention(thin) (@guaranteed any SomeProtocol, @guaranteed any SomeProtocol) -> (Int, Int) {
 sil hidden [noinline] @$s1t7wrapFoo1a1bSi_SitAA12SomeProtocol_p_AaE_ptF : $@convention(thin) (@guaranteed SomeProtocol, @guaranteed SomeProtocol) -> (Int, Int) {
 bb0(%0 : $SomeProtocol, %1 : $SomeProtocol):
   debug_value %0 : $SomeProtocol, let, name "a", argno 1
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_spec_and_inline.swift b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_spec_and_inline.swift
deleted file mode 100644
index de0c3b87511f3..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_spec_and_inline.swift
+++ /dev/null
@@ -1,24 +0,0 @@
-// RUN: %target-swift-frontend -parse-as-library -O -module-name=test -experimental-swift-based-closure-specialization %s -emit-sil | %FileCheck %s
-// XFAIL: *
-
-func closure(_ a: Int, b: Int) -> Bool {
-  return a < b
-}
-
-// Check that closure() is inlined into call_closure after call_closure is
-// specialized for it.
-
-// CHECK-LABEL: sil shared [noinline] @$s4test12call_closureySbSi_SiSbSi_SitXEtF27$s4test7closure_1bSbSi_SitFTf1nnc_n
-// CHECK-NOT: apply
-// CHECK: builtin "cmp_slt_Int
-// CHECK-NOT: apply
-// CHECK: return
-@inline(never)
-func call_closure(_ a: Int, _ b: Int, _ f: (Int , Int) -> Bool) -> Bool {
-  return f(a, b)
-}
-
-public func testit() -> Bool {
-  return call_closure(0, 1, closure)
-}
-
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize.sil b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize.sil
deleted file mode 100644
index 116c527a6273a..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize.sil
+++ /dev/null
@@ -1,943 +0,0 @@
-// RUN: %target-sil-opt -enable-sil-verify-all -experimental-swift-based-closure-specialization %s | %FileCheck %s
-// XFAIL: *
-
-import Builtin
-import Swift
-
-// CHECK-LABEL: sil shared [noinline] @$s7specgen12take_closureyyySi_SitcF023$s7specgen6calleryySiFyE8_SitcfU_SiTf1c_n : $@convention(thin) (Int) -> () {
-
-// CHECK: bb0(%0 : $Int)
-// CHECK: function_ref @$s7specgen6calleryySiFySi_SitcfU_
-// CHECK: partial_apply
-
-// CHECK-LABEL: sil shared [noinline] @$s7specgen12take_closureyyySi_SitcF26$s7specgen6calleeyySi_SitFTf1c_n : $@convention(thin) () -> () {
-// CHECK-NEXT: bb0:
-// CHECK: [[FUN:%.*]] = function_ref @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> ()
-// CHECK: thin_to_thick_function [[FUN]] : $@convention(thin) (Int, Int) -> () to $@callee_owned (Int, Int) -> ()
-
-// CHECK-LABEL: sil [noinline] @$s7specgen12take_closureyyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () {
-sil [noinline] @$s7specgen12take_closureyyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () {
-bb0(%0 : $@callee_owned (Int, Int) -> ()):
-  %1 = alloc_stack $Int
-  %2 = load %1 : $*Int
-  %3 = apply %0(%2, %2) : $@callee_owned (Int, Int) -> ()
-  dealloc_stack %1 : $*Int
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil shared [noinline] @$s7specgen13take_closure2yyySi_SitcF023$s7specgen6calleryySiFyE8_SitcfU_SiTf1c_n : $@convention(thin) (Int) -> () {
-// CHECK: bb0(%0 : $Int)
-// CHECK: [[FUN:%.*]] = function_ref @$s7specgen6calleryySiFySi_SitcfU_
-// CHECK: partial_apply [[FUN]](
-
-// CHECK-LABEL: sil shared [noinline] @$s7specgen13take_closure2yyySi_SitcF26$s7specgen6calleeyySi_SitFTf1c_n : $@convention(thin) () -> () {
-// CHECK-NEXT: bb0:
-// CHECK: [[FUN:%.*]] = function_ref @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> ()
-// CHECK: thin_to_thick_function [[FUN]] : $@convention(thin) (Int, Int) -> () to $@callee_owned (Int, Int) -> ()
-
-// CHECK-LABEL: sil [noinline] @$s7specgen13take_closure2yyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () {
-sil [noinline] @$s7specgen13take_closure2yyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () {
-bb0(%0 : $@callee_owned (Int, Int) -> ()):
-  %1 = alloc_stack $Int
-  %2 = load %1 : $*Int
-  %3 = apply %0(%2, %2) : $@callee_owned (Int, Int) -> ()
-  dealloc_stack %1 : $*Int
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil [noinline] @$s7specgen6calleeyySi_S2itF : $@convention(thin) (Int, Int, Int) -> () {
-// specgen.callee (Swift.Int, Swift.Int, Swift.Int) -> ()
-sil [noinline] @$s7specgen6calleeyySi_S2itF : $@convention(thin) (Int, Int, Int) -> () {
-bb0(%0 : $Int, %1 : $Int, %2 : $Int):
-  %6 = tuple ()                                   // user: %7
-  return %6 : $()                                 // id: %7
-}
-
-// CHECK-LABEL: sil @$s7specgen6calleryySiF : $@convention(thin) (Int) -> () {
-// CHECK: [[ID1:%[0-9]+]] = function_ref @$s7specgen13take_closure2yyySi_SitcF023$s7specgen6calleryySiFyE8_SitcfU_SiTf1c_n : $@convention(thin) (Int) -> ()
-// CHECK: [[ID2:%[0-9]+]] = function_ref @$s7specgen12take_closureyyySi_SitcF023$s7specgen6calleryySiFyE8_SitcfU_SiTf1c_n : $@convention(thin) (Int) -> ()
-// CHECK: apply [[ID2]](%0) : $@convention(thin) (Int) -> ()
-// CHECK: apply [[ID1]](%0) : $@convention(thin) (Int) -> ()
-sil @$s7specgen6calleryySiF : $@convention(thin) (Int) -> () {
-bb0(%0 : $Int):
-  // function_ref specgen.take_closure ((Swift.Int, Swift.Int) -> ()) -> ()
-  %2 = function_ref @$s7specgen12take_closureyyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () // user: %5
-  // function_ref specgen.(caller (Swift.Int) -> ()).(closure #1)
-  %3 = function_ref @$s7specgen6calleryySiFySi_SitcfU_ : $@convention(thin) (Int, Int, Int) -> () // user: %4
-  %4 = partial_apply %3(%0) : $@convention(thin) (Int, Int, Int) -> () // user: %5
-  strong_retain %4 : $@callee_owned (Int, Int) -> ()
-  %5 = apply %2(%4) : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
-  %6 = function_ref @$s7specgen13take_closure2yyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () // user: %5
-  strong_retain %4 : $@callee_owned (Int, Int) -> ()
-  %7 = apply %6(%4) : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
-  strong_release %4 : $@callee_owned (Int, Int) -> ()
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil shared @$s7specgen6calleryySiFySi_SitcfU_ : $@convention(thin) (Int, Int, Int) -> () {
-sil shared @$s7specgen6calleryySiFySi_SitcfU_ : $@convention(thin) (Int, Int, Int) -> () {
-bb0(%0 : $Int, %1 : $Int, %2 : $Int):
-  %5 = alloc_box $<τ_0_0> { var τ_0_0 } <Int>, var, name "p"                   // users: %6, %10, %14
-  %5a = project_box %5 : $<τ_0_0> { var τ_0_0 } <Int>, 0
-  store %0 to %5a : $*Int                        // id: %6
-  %7 = alloc_box $<τ_0_0> { var τ_0_0 } <Int>, var, name "q"                   // users: %8, %11, %13
-  %7a = project_box %7 : $<τ_0_0> { var τ_0_0 } <Int>, 0
-  store %1 to %7a : $*Int                        // id: %8
-  // function_ref specgen.callee (Swift.Int, Swift.Int, Swift.Int) -> ()
-  %9 = function_ref @$s7specgen6calleeyySi_S2itF : $@convention(thin) (Int, Int, Int) -> () // user: %12
-  %10 = load %5a : $*Int                         // user: %12
-  %11 = load %7a : $*Int                         // user: %12
-  %12 = apply %9(%10, %11, %2) : $@convention(thin) (Int, Int, Int) -> ()
-  strong_release %7 : $<τ_0_0> { var τ_0_0 } <Int>
-  strong_release %5 : $<τ_0_0> { var τ_0_0 } <Int>
-  %15 = tuple ()                                  // user: %16
-  return %15 : $()                                // id: %16
-}
-
-//////////////////////////////////
-// Thin To Thick Function Tests //
-//////////////////////////////////
-
-// CHECK-LABEL: sil [noinline] @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> () {
-// specgen.callee (Swift.Int, Swift.Int) -> ()
-sil [noinline] @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> () {
-bb0(%0 : $Int, %1 : $Int):
-  %6 = tuple ()                                   // user: %7
-  return %6 : $()                                 // id: %7
-}
-
-// CHECK-LABEL: sil @$s7specgen11tttficalleryySiF : $@convention(thin) (Int) -> () {
-// CHECK: [[ID1:%[0-9]+]] = function_ref @$s7specgen13take_closure2yyySi_SitcF26$s7specgen6calleeyySi_SitFTf1c_n : $@convention(thin) () -> ()
-// CHECK: [[ID2:%[0-9]+]] = function_ref @$s7specgen12take_closureyyySi_SitcF26$s7specgen6calleeyySi_SitFTf1c_n : $@convention(thin) () -> ()
-// CHECK: apply [[ID2]]() : $@convention(thin) () -> ()
-// CHECK: apply [[ID1]]() : $@convention(thin) () -> ()
-sil @$s7specgen11tttficalleryySiF : $@convention(thin) (Int) -> () {
-bb0(%0 : $Int):
-  // function_ref specgen.take_closure ((Swift.Int, Swift.Int) -> ()) -> ()
-  %2 = function_ref @$s7specgen12take_closureyyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> () // user: %5
-  // function_ref specgen.(caller (Swift.Int) -> ()).(closure #1)
-  %3 = function_ref @$s7specgen6calleeyySi_SitF : $@convention(thin) (Int, Int) -> () // user: %4
-  %4 = thin_to_thick_function %3 : $@convention(thin) (Int, Int) -> () to $@callee_owned (Int, Int) -> () // user: %5
-  %5 = apply %2(%4) : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
-  %6 = function_ref @$s7specgen13take_closure2yyySi_SitcF : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
-  %7 = apply %6(%4) : $@convention(thin) (@owned @callee_owned (Int, Int) -> ()) -> ()
-  %9999 = tuple ()                                   // user: %7
-  return %9999 : $()                                 // id: %7
-}
-
-// We don't handle closures that close over address types (*NOTE* this includes
-// address and non-address only types) taken as @in or @in_guaranteed.
-
-// This is a temporary limitation.
-// TODO: figure out what to do with non-inout indirect arguments
-// https://forums.swift.org/t/non-inout-indirect-types-not-supported-in-closure-specialization-optimization/70826
-// CHECK-LABEL: sil @address_closure : $@convention(thin) (@in Int) -> () {
-sil @address_closure : $@convention(thin) (@in Int) -> () {
-bb0(%0 : $*Int):
-  %6 = tuple()
-  return %6 : $()
-}
-
-// CHECK-LABEL: sil @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
-sil @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
-bb0(%0 : $@callee_owned () -> ()):
-  %1 = apply %0() : $@callee_owned () -> ()
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil @address_caller : $@convention(thin) (@in Int) -> () {
-// CHECK-NOT: _TTSf1cl15address_closureSi__address_closure_user
-sil @address_caller : $@convention(thin) (@in Int) -> () {
-bb0(%0 : $*Int):
-  %1 = function_ref @address_closure : $@convention(thin) (@in Int) -> ()
-  %2 = partial_apply %1(%0) : $@convention(thin) (@in Int) -> ()
-  %3 = function_ref @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %4 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-class A {}
-
-sil hidden [noinline] @closure : $@convention(thin) (@owned A, @owned A) -> () {
-bb0(%0 : $A, %1 : $A):
-  strong_release %1 : $A
-  strong_release %0 : $A
-  %4 = tuple ()
-  return %4 : $()
-}
-
-// CHECK-LABEL: sil shared {{.*}} @$s11use_closure{{.*}}Tf{{.*}} : $@convention(thin) (@owned A) -> () {
-sil hidden [noinline] @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> () {
-bb0(%0 : $@callee_owned (@owned A) -> ()):
-  %1 = alloc_ref $A
-  %2 = apply %0(%1) : $@callee_owned (@owned A) -> ()
-  %3 = tuple ()
-  return %3 : $()
-}
-
-// CHECK-LABEL: sil shared {{.*}} @$s17use_closure_throw{{.*}}Tf{{.*}} : $@convention(thin) (@owned A) -> @error any Error {
-sil hidden [noinline] @use_closure_throw : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> @error any Error {
-bb0(%0 : $@callee_owned (@owned A) -> ()):
-  %1 = alloc_ref $A
-  %2 = apply %0(%1) : $@callee_owned (@owned A) -> ()
-  %3 = tuple ()
-  return %3 : $()
-}
-
-// CHECK-LABEL: sil {{.*}} @different_execution_counts
-// CHECK: bb0([[ARG:%.*]] : $A
-// CHECK:   strong_retain [[ARG]]
-// CHECK-NOT: partial_apply
-// CHECK:  [[SPECIALIZED_CLOSURE_USER:%.*]] = function_ref @$s11use_closure{{.*}}Tf
-// CHECK:   retain_value [[ARG]]
-// CHECK-NOT: partial_apply
-// CHECK:   integer_literal $Builtin.Int64, 0
-// CHECK: br bb2
-
-// CHECK: bb1:
-// CHECK:  strong_release [[ARG]]
-// CHECK:  release_value [[ARG]]
-// CHECK:  return
-
-// CHECK: bb2({{.*}}):
-// Match the partial_apply consume of arg.
-// CHECK: retain_value [[ARG]]
-// CHECK: apply [[SPECIALIZED_CLOSURE_USER]]([[ARG]])
-// CHECK: cond_br {{.*}}, bb1, bb3
-
-sil hidden [noinline] @different_execution_counts : $@convention(thin) (@guaranteed A) -> () {
-bb0(%0 : $A):
-  strong_retain %0 : $A
-  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
-  %3 = partial_apply %2(%0) : $@convention(thin) (@owned A, @owned A) -> ()
-  %4 = integer_literal $Builtin.Int64, 0
-  %5 = integer_literal $Builtin.Int64, 5
-  %6 = integer_literal $Builtin.Int64, 1
-  %7 = integer_literal $Builtin.Int1, 0
-  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  br bb2(%4 : $Builtin.Int64)
-
-bb1:
-  strong_release %3 : $@callee_owned (@owned A) -> ()
-  %11 = tuple ()
-  return %11 : $()
-
-bb2(%13 : $Builtin.Int64):
-  %14 = builtin "sadd_with_overflow_Int64"(%13 : $Builtin.Int64, %6 : $Builtin.Int64, %7 : $Builtin.Int1) : $(Builtin.Int64, Builtin.Int1)
-  %15 = tuple_extract %14 : $(Builtin.Int64, Builtin.Int1), 0
-  strong_retain %3 : $@callee_owned (@owned A) -> ()
-  %17 = apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  %18 = builtin "cmp_eq_Int64"(%15 : $Builtin.Int64, %5 : $Builtin.Int64) : $Builtin.Int1
-  cond_br %18, bb1, bb3
-
-bb3:
-  br bb2(%15 : $Builtin.Int64)
-}
-
-// CHECK-LABEL: sil @insert_release_in_liferange_exit_block
-// CHECK: bb0(%0 : $A):
-// CHECK:   retain_value %0
-// CHECK: bb1:
-// CHECK-NEXT: release_value %0
-// CHECK-NEXT: br bb3
-// CHECK: bb2:
-// CHECK:   retain_value %0
-// CHECK:   apply %{{[0-9]+}}(%0)
-// CHECK:   release_value %0
-// CHECK: bb3:
-// CHECK-NOT: %0
-// CHECK:   return
-sil @insert_release_in_liferange_exit_block : $@convention(thin) (@guaranteed A) -> () {
-bb0(%0 : $A):
-  strong_retain %0 : $A
-  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
-  %3 = partial_apply %2(%0) : $@convention(thin) (@owned A, @owned A) -> ()
-  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  %5 = partial_apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  cond_br undef, bb1, bb2
-
-bb1:
-  br bb3
-
-bb2:
-  strong_retain %3 : $@callee_owned (@owned A) -> ()
-  %17 = apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  br bb3
-
-bb3:
-  strong_release %5 : $@callee_owned () -> ()
-  %11 = tuple ()
-  return %11 : $()
-}
-
-// CHECK-LABEL: sil @insert_release_at_critical_edge
-// CHECK: bb0(%0 : $A):
-// CHECK:   retain_value %0
-// CHECK: bb1:
-// CHECK-NEXT: release_value %0
-// CHECK-NEXT: br bb3
-// CHECK: bb2:
-// CHECK:   retain_value %0
-// CHECK:   apply %{{[0-9]+}}(%0)
-// CHECK:   release_value %0
-// CHECK: bb3:
-// CHECK-NOT: %0
-// CHECK:   return
-sil @insert_release_at_critical_edge : $@convention(thin) (@guaranteed A) -> () {
-bb0(%0 : $A):
-  strong_retain %0 : $A
-  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
-  %3 = partial_apply %2(%0) : $@convention(thin) (@owned A, @owned A) -> ()
-  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  %5 = partial_apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  cond_br undef, bb1, bb2
-
-bb1:
-  strong_retain %3 : $@callee_owned (@owned A) -> ()
-  %17 = apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  br bb2
-
-bb2:
-  strong_release %5 : $@callee_owned () -> ()
-  %11 = tuple ()
-  return %11 : $()
-}
-
-// CHECK-LABEL: sil @insert_release_at_critical_loop_exit_edge
-// CHECK: bb0(%0 : $A):
-// CHECK:   retain_value %0
-// CHECK: bb1:
-// CHECK-NEXT:   br bb2
-// CHECK: bb2:
-// CHECK:   retain_value %0
-// CHECK:   apply %{{[0-9]+}}(%0)
-// CHECK-NOT:   %0
-// CHECK: bb3:
-// CHECK-NEXT: release_value %0
-// CHECK-NEXT: br bb5
-// CHECK: bb4:
-// CHECK-NEXT: release_value %0
-// CHECK-NEXT: br bb5
-// CHECK: bb5:
-// CHECK-NOT: %0
-// CHECK:   return
-sil @insert_release_at_critical_loop_exit_edge : $@convention(thin) (@guaranteed A) -> () {
-bb0(%0 : $A):
-  strong_retain %0 : $A
-  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
-  %3 = partial_apply %2(%0) : $@convention(thin) (@owned A, @owned A) -> ()
-  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  %5 = partial_apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  cond_br undef, bb3, bb1
-
-bb1:
-  br bb2
-
-bb2:
-  strong_retain %3 : $@callee_owned (@owned A) -> ()
-  %17 = apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  cond_br undef, bb2, bb4
-
-bb3:
-  br bb4
-
-bb4:
-  strong_release %5 : $@callee_owned () -> ()
-  %11 = tuple ()
-  return %11 : $()
-}
-
-// CHECK-LABEL: sil @insert_release_in_loop_exit_block
-// CHECK: bb0(%0 : $A):
-// CHECK:   retain_value %0
-// CHECK: bb1:
-// CHECK-NEXT:   br bb2
-// CHECK: bb2:
-// CHECK:   retain_value %0
-// CHECK:   apply %{{[0-9]+}}(%0)
-// CHECK-NOT:   %0
-// CHECK: bb3:
-// CHECK-NEXT: release_value %0
-// CHECK-NOT: %0
-// CHECK:   return
-sil @insert_release_in_loop_exit_block : $@convention(thin) (@guaranteed A) -> () {
-bb0(%0 : $A):
-  strong_retain %0 : $A
-  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
-  %3 = partial_apply %2(%0) : $@convention(thin) (@owned A, @owned A) -> ()
-  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  %5 = partial_apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  cond_br undef, bb3, bb1
-
-bb1:
-  br bb2
-
-bb2:
-  strong_retain %3 : $@callee_owned (@owned A) -> ()
-  %17 = apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> ()
-  cond_br undef, bb2, bb3
-
-bb3:
-  strong_release %5 : $@callee_owned () -> ()
-  %11 = tuple ()
-  return %11 : $()
-}
-
-// CHECK-LABEL: sil @insert_release_after_try_apply
-// CHECK: bb0(%0 : $A):
-// CHECK:   retain_value %0
-// CHECK: bb1:
-// CHECK:   retain_value %0
-// CHECK-NEXT:   try_apply
-// CHECK: bb2(%{{[0-9]+}} : $()):
-// CHECK-NEXT:   strong_release %0
-// CHECK-NEXT:   release_value %0
-// CHECK-NEXT:   br bb4
-// CHECK: bb3(%{{[0-9]+}} : $any Error):
-// CHECK-NEXT:   strong_release %0
-// CHECK-NEXT:   release_value %0
-// CHECK-NEXT:   br bb4
-// CHECK: bb4:
-// CHECK-NOT: %0
-// CHECK:   return
-sil @insert_release_after_try_apply : $@convention(thin) (@guaranteed A) -> () {
-bb0(%0 : $A):
-  %2 = function_ref @closure : $@convention(thin) (@owned A, @owned A) -> ()
-  %3 = partial_apply %2(%0) : $@convention(thin) (@owned A, @owned A) -> ()
-  %8 = function_ref @use_closure_throw : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> @error Error
-  br bb1
-
-bb1:
-  strong_retain %3 : $@callee_owned (@owned A) -> ()
-  try_apply %8(%3) : $@convention(thin) (@owned @callee_owned (@owned A) -> ()) -> @error Error, normal bb2, error bb3
-
-bb2(%n : $()):
-  br bb4
-
-bb3(%e : $Error):
-  br bb4
-
-bb4:
-  %11 = tuple ()
-  return %11 : $()
-}
-
-
-// Ensure that we can specialize and properly mangle functions that take closures with <τ_0_0> { var τ_0_0 } <arguments>.
-
-// CHECK-LABEL: sil shared [noinline] @$s4main5inneryys5Int32Vz_yADctF25closure_with_box_argumentxz_Bi32__lXXTf1nc_n : $@convention(thin) (@inout Builtin.Int32, @owned <τ_0_0> { var τ_0_0 } <Builtin.Int32>) -> ()
-// CHECK: bb0
-// CHECK: [[FN:%.*]] = function_ref @closure_with_box_argument
-// CHECK: [[PARTIAL:%.*]] = partial_apply [[FN]](%1)
-// CHECK: [[ARG:%.*]] = load %0
-// CHECK: apply [[PARTIAL]]([[ARG]])
-
-// CHECK-LABEL: {{.*}} @$s4main5inneryys5Int32Vz_yADctF
-sil hidden [noinline] @$s4main5inneryys5Int32Vz_yADctF : $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> () {
-bb0(%0 : $*Builtin.Int32, %1 : $@callee_owned (Builtin.Int32) -> ()):
-  strong_retain %1 : $@callee_owned (Builtin.Int32) -> ()
-  %5 = load %0 : $*Builtin.Int32
-  %6 = apply %1(%5) : $@callee_owned (Builtin.Int32) -> ()
-  %11 = tuple ()
-  return %11 : $()
-}
-
-// CHECK-LABEL: sil @pass_a_closure
-sil @pass_a_closure: $@convention(thin) () -> Builtin.Int32 {
-bb0:
-  %0 = alloc_box $<τ_0_0> { var τ_0_0 } <Builtin.Int32>, var, name "i"
-  %0a = project_box %0 : $<τ_0_0> { var τ_0_0 } <Builtin.Int32>, 0
-  %1 = integer_literal $Builtin.Int32, 0
-  store %1 to %0a : $*Builtin.Int32
-  %4 = function_ref @closure_with_box_argument : $@convention(thin) (Builtin.Int32, @owned <τ_0_0> { var τ_0_0 } <Builtin.Int32>) -> ()
-  strong_retain %0 : $<τ_0_0> { var τ_0_0 } <Builtin.Int32>
-  %6 = partial_apply %4(%0) : $@convention(thin) (Builtin.Int32, @owned <τ_0_0> { var τ_0_0 } <Builtin.Int32>) -> ()
-  %7 = alloc_stack $Builtin.Int32
-  %9 = integer_literal $Builtin.Int32, 1
-  store %9 to %7 : $*Builtin.Int32
-  %12 = function_ref @$s4main5inneryys5Int32Vz_yADctF: $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> ()
-  strong_retain %6 : $@callee_owned (Builtin.Int32) -> ()
-  %14 = apply %12(%7, %6) : $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> ()
-  strong_release %6 : $@callee_owned (Builtin.Int32) -> ()
-  %16 = tuple ()
-  dealloc_stack %7 : $*Builtin.Int32
-  %18 = load %0a : $*Builtin.Int32
-  strong_release %0 : $<τ_0_0> { var τ_0_0 } <Builtin.Int32>
-  return %18 : $Builtin.Int32
-}
-
-// CHECK-LABEL: sil shared @closure_with_box_argument
-sil shared @closure_with_box_argument : $@convention(thin) (Builtin.Int32, @owned <τ_0_0> { var τ_0_0 } <Builtin.Int32>) -> () {
-bb0(%0 : $Builtin.Int32, %1 : $<τ_0_0> { var τ_0_0 } <Builtin.Int32>):
-  %3 = project_box %1 : $<τ_0_0> { var τ_0_0 } <Builtin.Int32>, 0
-  store %0 to %3 : $*Builtin.Int32
-  strong_release %1 : $<τ_0_0> { var τ_0_0 } <Builtin.Int32>
-  %7 = tuple ()
-  return %7 : $()
-}
-
-// Check that we don't crash with this:
-// CHECK-LABEL: sil @test_box_with_named_elements_tuple
-sil @test_box_with_named_elements_tuple: $@convention(thin) () -> Builtin.Int32 {
-bb0:
-  %0 = alloc_box ${ let (first: Builtin.Int32, second: Builtin.Int32) }
-  %0p = project_box %0 : ${ let (first: Builtin.Int32, second: Builtin.Int32) }, 0
-  %0a = tuple_element_addr %0p : $*(first: Builtin.Int32, second: Builtin.Int32), 0
-  %0b = tuple_element_addr %0p : $*(first: Builtin.Int32, second: Builtin.Int32), 1
-  %1 = integer_literal $Builtin.Int32, 0
-  store %1 to %0a : $*Builtin.Int32
-  store %1 to %0b : $*Builtin.Int32
-  %4 = function_ref @closure_with_named_elements_tuple : $@convention(thin) (Builtin.Int32, @owned { let (first: Builtin.Int32, second: Builtin.Int32) }) -> ()
-  strong_retain %0 : ${ let (first: Builtin.Int32, second: Builtin.Int32) }
-  %6 = partial_apply %4(%0) : $@convention(thin) (Builtin.Int32, @owned { let (first: Builtin.Int32, second: Builtin.Int32) }) -> ()
-  %7 = alloc_stack $Builtin.Int32
-  %9 = integer_literal $Builtin.Int32, 1
-  store %9 to %7 : $*Builtin.Int32
-  %12 = function_ref @$s4main5inneryys5Int32Vz_yADctF: $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> ()
-  strong_retain %6 : $@callee_owned (Builtin.Int32) -> ()
-  %14 = apply %12(%7, %6) : $@convention(thin) (@inout Builtin.Int32, @owned @callee_owned (Builtin.Int32) -> ()) -> ()
-  strong_release %6 : $@callee_owned (Builtin.Int32) -> ()
-  %16 = tuple ()
-  dealloc_stack %7 : $*Builtin.Int32
-  %18 = load %0a : $*Builtin.Int32
-  strong_release %0 : ${ let (first: Builtin.Int32, second: Builtin.Int32) }
-  return %18 : $Builtin.Int32
-}
-
-// CHECK-LABEL: sil shared @closure_with_named_elements_tuple
-sil shared @closure_with_named_elements_tuple : $@convention(thin) (Builtin.Int32, @owned { let (first: Builtin.Int32, second: Builtin.Int32) }) -> () {
-bb0(%0 : $Builtin.Int32, %1 : ${ let (first: Builtin.Int32, second: Builtin.Int32) }):
-  %3 = project_box %1 : ${ let (first: Builtin.Int32, second: Builtin.Int32) }, 0
-  %4 = tuple_element_addr %3 : $*(first: Builtin.Int32, second: Builtin.Int32), 0
-  store %0 to %4 : $*Builtin.Int32
-  strong_release %1 : ${ let (first: Builtin.Int32, second: Builtin.Int32) }
-  %7 = tuple ()
-  return %7 : $()
-}
-
-
-// The specialized function should always be a thin function, regardless of the
-// representation of the original function.
-
-public protocol P {
-  static func foo(cl: () -> Int) -> Int
-}
-
-public struct S : P {
-  public static func foo(cl: () -> Int) -> Int
-  init()
-}
-
-// CHECK-LABEL: sil shared @$s4test1SVAA1PA2aDP3fooyS2iycFZTW8closure2SiTf1cn_n : $@convention(thin) (@thick S.Type, Int) -> Int
-sil @$s4test1SVAA1PA2aDP3fooyS2iycFZTW : $@convention(witness_method: P) (@owned @callee_owned () -> Int, @thick S.Type) -> Int {
-bb0(%0 : $@callee_owned () -> Int, %1 : $@thick S.Type):
-  %3 = apply %0() : $@callee_owned () -> Int
-  return %3 : $Int
-}
-
-sil shared @closure2 : $@convention(thin) (Int) -> Int {
-bb0(%0 : $Int):
-  return %0 : $Int
-}
-
-sil @call_witness_method : $@convention(thin) (Int, S) -> Int {
-bb0(%0 : $Int, %1 : $S):
-  %3 = function_ref @closure2 : $@convention(thin) (Int) -> Int
-  %4 = partial_apply %3(%0) : $@convention(thin) (Int) -> Int
-  %5 = metatype $@thick S.Type
-  %6 = function_ref @$s4test1SVAA1PA2aDP3fooyS2iycFZTW : $@convention(witness_method: P) (@owned @callee_owned () -> Int, @thick S.Type) -> Int
-  %7 = apply %6(%4, %5) : $@convention(witness_method: P) (@owned @callee_owned () -> Int, @thick S.Type) -> Int
-  return %7 : $Int
-}
-
-sil_witness_table S: P module test {
-  method #P.foo: @$s4test1SVAA1PA2aDP3fooyS2iycFZTW
-}
-
-// Test partial_apply -> convert_function -> convert_function -> try_apply.
-sil @testClosureConvertHelper : $(Int) -> ()
-
-// specialized testClosureConvertThunk
-// FIXME: Need to handle closures with multiple exceptional exits.
-// CHECK-LABEL: sil shared @$s23testClosureConvertThunk0abC6HelperSiTf1nc_n : $@convention(thin) (Int) -> (@out (), @error any Error) {
-// CHECK: bb0(%0 : $*(), %1 : $Int):
-// CHECK:   [[F:%.*]] = function_ref @testClosureConvertHelper : $@convention(thin) (Int) -> ()
-// CHECK:   [[PA:%.*]] = partial_apply [[F]](%1) : $@convention(thin) (Int) -> ()
-// CHECK:   [[CVT1:%.*]] = convert_escape_to_noescape [[PA]] : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
-// CHECK:   [[CVT2:%.*]] = convert_function [[CVT1]] : $@noescape @callee_owned () -> () to $@noescape @callee_owned () -> @error any Error
-// CHECK:   try_apply [[CVT2]]() : $@noescape @callee_owned () -> @error any Error, normal bb1, error bb2
-// CHECK:  bb1
-// CHECK: release_value [[PA]]
-// CHECK: return
-// CHECK: bb2
-// CHECK: release_value [[PA]]
-// CHECK: throw
-// CHECK-LABEL: } // end sil function '$s23testClosureConvertThunk0abC6HelperSiTf1nc_n'
-sil @testClosureConvertThunk : $@convention(thin) (@noescape @callee_owned () -> @error Error) -> (@out (), @error Error) {
-bb0(%0 : $*(), %1 : $@noescape @callee_owned () -> @error Error):
-  try_apply %1() : $@noescape @callee_owned () -> @error Error, normal bb1, error bb2
-
-bb1(%7 : $()):
-  %8 = tuple ()
-  return %8 : $()
-
-bb2(%10 : $Error):
-  throw %10 : $Error
-}
-
-// Test closure specialization when the closure type is converted before application.
-sil @testClosureConvert : $(Int) -> () {
-bb0(%0 : $Int):
-  %48 = alloc_stack $()
-  %49 = function_ref @testClosureConvertHelper : $@convention(thin) (Int) -> ()
-  %50 = partial_apply %49(%0) : $@convention(thin) (Int) -> ()
-  %51 = convert_escape_to_noescape %50 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
-  %52 = convert_function %51 : $@noescape @callee_owned () -> () to $@noescape @callee_owned () -> @error Error
-  %53 = function_ref @testClosureConvertThunk : $@convention(thin) (@noescape @callee_owned () -> @error Error) -> (@out (), @error Error)
-  try_apply %53(%48, %52) : $@convention(thin) (@noescape @callee_owned () -> @error Error) -> (@out (), @error Error), normal bb7, error bb11
-
-bb7(%callret : $()):
-  br bb99
-
-bb11(%128 : $Error):
-  br bb99
-
-bb99:
-  dealloc_stack %48 : $*()
-  %empty = tuple ()
-  return %empty : $()
-}
-
-sil @testClosureThunkNoEscape : $@convention(thin) (@noescape @callee_guaranteed () -> ()) -> () {
-bb0(%0 : $@noescape @callee_guaranteed () -> ()):
-  apply %0() : $@noescape @callee_guaranteed () -> ()
-  %8 = tuple ()
-  return %8 : $()
-}
-
-// CHECK-LABEL: sil shared @$s24testClosureThunkNoEscape0aB13ConvertHelperSiTf1c_n : $@convention(thin) (Int) -> () {
-// CHECK: bb0([[ARG:%.*]] : $Int):
-// CHECK:   [[F:%.*]] = function_ref @testClosureConvertHelper : $@convention(thin) (Int) -> ()
-// CHECK:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[F]]([[ARG]]) : $@convention(thin) (Int) -> ()
-// CHECK:   [[E:%.*]] = convert_escape_to_noescape [[PA]] : $@callee_guaranteed () -> () to $@noescape @callee_guaranteed () -> ()
-// CHECK:   apply [[E]]() : $@noescape @callee_guaranteed () -> ()
-// CHECK:   release_value [[PA]]
-// CHECK:   return
-// CHECK: }
-// CHECK-LABEL: sil @testClosureNoEscape : $@convention(thin) (Int) -> () {
-// CHECK-NOT: partial_apply
-// CHECK:   [[FN:%.*]] = function_ref @$s24testClosureThunkNoEscape0aB13ConvertHelperSiTf1c_n : $@convention(thin) (Int) -> ()
-// CHECK-NOT: partial_apply
-// CHECK:   %5 = apply [[FN]](%0) : $@convention(thin) (Int) -> ()
-// CHECK-NOT: release
-// CHECK:   return
-// CHECK: }
-
-sil @testClosureNoEscape : $(Int) -> () {
-bb0(%0 : $Int):
-  %48 = alloc_stack $()
-  %49 = function_ref @testClosureConvertHelper : $@convention(thin) (Int) -> ()
-  %50 = partial_apply [callee_guaranteed] %49(%0) : $@convention(thin) (Int) -> ()
-  %51 = convert_escape_to_noescape %50 : $@callee_guaranteed () -> () to $@noescape @callee_guaranteed () -> ()
-  %53 = function_ref @testClosureThunkNoEscape : $@convention(thin) (@noescape @callee_guaranteed () -> ()) -> ()
-  apply %53(%51) : $@convention(thin) (@noescape @callee_guaranteed () -> ()) -> ()
-  release_value %50: $@callee_guaranteed () ->()
-  dealloc_stack %48 : $*()
-  %empty = tuple ()
-  return %empty : $()
-}
-
-
-sil @testClosureConvertHelper2 : $(Int) -> Int
-
-sil @testClosureThunkNoEscape2 : $@convention(thin) (@noescape @callee_guaranteed () -> @out Int) -> @out Int {
-bb0(%0 : $*Int, %1 : $@noescape @callee_guaranteed () -> @out Int):
-  apply %1(%0) : $@noescape @callee_guaranteed () -> @out Int
-  %8 = tuple ()
-  return %8 : $()
-}
-
-sil [reabstraction_thunk] @reabstractionThunk : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-
-// CHECK-LABEL: sil shared @$s25testClosureThunkNoEscape20aB14ConvertHelper2SiTf1nc_n : $@convention(thin) (Int) -> @out Int
-// CHECK: [[PA1:%.*]] = partial_apply
-// CHECK: convert_escape_to_noescape
-// CHECK: [[PA2:%.*]] = partial_apply
-// CHECK: convert_escape_to_noescape
-// CHECK: apply
-// CHECK: release_value [[PA1]]
-// CHECK: release_value [[PA2]]
-// CHECK: return
-
-// CHECK-LABEL: sil shared @$s25testClosureThunkNoEscape219reabstractionThunk2SiIegd_Tf1nc_n : $@convention(thin) (@owned @callee_guaranteed () -> Int) -> @out Int {
-// CHECK: bb0(%0 : $*Int, %1 : $@callee_guaranteed () -> Int):
-// CHECK:   [[F:%.*]] = function_ref @reabstractionThunk2
-// CHECK:   [[PA:%.*]] = partial_apply [callee_guaranteed] [[F]](%1)
-// CHECK:   [[CVT:%.*]] = convert_escape_to_noescape [[PA]]
-// CHECK:   apply [[CVT]](%0) : $@noescape @callee_guaranteed () -> @out Int
-// CHECK:   release_value [[PA]] : $@callee_guaranteed () -> @out Int
-// CHECK: return
-
-// CHECK-LABEL: sil @reabstractionTest : $@convention(thin) (Int) -> ()
-// CHECK: [[F:%.*]] = function_ref @$s25testClosureThunkNoEscape20aB14ConvertHelper2SiTf1nc_n
-// CHECK: apply [[F]]
-// CHECK: return
-sil @reabstractionTest : $(Int) -> () {
-bb0(%0 : $Int):
-  %48 = alloc_stack $Int
-  %49 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
-  %50 = partial_apply [callee_guaranteed] %49(%0) : $@convention(thin) (Int) -> Int
-  %51 = convert_escape_to_noescape %50 : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
-  %52 = function_ref @reabstractionThunk : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-  %53 = partial_apply [callee_guaranteed] %52(%51) : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-  %54 = convert_escape_to_noescape %53 : $@callee_guaranteed () -> @out Int to $@noescape @callee_guaranteed () -> @out Int
-  %55 = function_ref @testClosureThunkNoEscape2 : $@convention(thin) (@noescape @callee_guaranteed () -> @out Int) -> @out Int
-  apply %55(%48, %54) : $@convention(thin) (@noescape @callee_guaranteed () -> @out Int) -> @out Int
-  release_value %50: $@callee_guaranteed () -> Int
-  release_value %53: $@callee_guaranteed () -> @out Int
-  dealloc_stack %48 : $*Int
-  %empty = tuple ()
-  return %empty : $()
-}
-
-sil @testClosureConvertHelper3 : $@convention(thin) (Int) -> Int
-sil [reabstraction_thunk] @reabstractionThunk3 : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-
-sil @testClosureThunkNoEscape3 : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>) -> @out () {
-entry(%empty : $*(), %closure : $@noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>):
-  %out = alloc_stack $Int
-  %ret = apply %closure(%out) : $@noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>
-  dealloc_stack %out : $*Int
-  store %ret to %empty : $*()
-  %retval = tuple ()
-  return %retval : $()
-}
-
-// CHECK-LABEL: sil @reabstractionTest4 {{.*}} {
-// CHECK:         [[HELPER:%[^,]+]] = function_ref @testClosureConvertHelper3
-// CHECK:         [[SPECIALIZATION:%[^,]+]] = function_ref @$s25testClosureThunkNoEscape30aB14ConvertHelper3SiTf1nc_n
-// CHECK:         [[CLOSURE:%[^,]+]] = partial_apply [callee_guaranteed] [[HELPER]]
-// CHECK:         [[NOESCAPE_CLOSURE:%[^,]+]] = convert_escape_to_noescape [[CLOSURE]]
-// CHECK:         apply [[SPECIALIZATION]]{{.*}}
-// CHECK:         release_value [[CLOSURE]]
-// CHECK-NOT:     release_value [[CLOSURE]]
-// CHECK:         strong_release [[NOESCAPE_CLOSURE]]
-// CHECK-LABEL: } // end sil function 'reabstractionTest4'
-sil @reabstractionTest4 : $(Int) -> () {
-bb0(%value : $Int):
-  %testThrowingClosureConvertHelper = function_ref @testClosureConvertHelper3 : $@convention(thin) (Int) -> Int
-  %closure = partial_apply [callee_guaranteed] %testThrowingClosureConvertHelper(%value) : $@convention(thin) (Int) -> Int
-  %noescapeClosure = convert_escape_to_noescape %closure : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
-  %thunk = function_ref @reabstractionThunk3 : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-  %appliedThunk = partial_apply [callee_guaranteed] [on_stack] %thunk(%noescapeClosure) : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-
-  %dependency = mark_dependence %appliedThunk : $@noescape @callee_guaranteed () -> @out Int on %noescapeClosure : $@noescape @callee_guaranteed () -> Int
-  %generified = convert_function %dependency : $@noescape @callee_guaranteed () -> @out Int to $@noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>
-  %test = function_ref @testClosureThunkNoEscape3 : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>) -> @out ()
-  strong_retain %generified : $@noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>
-  %out = alloc_stack $()
-  %ret = apply %test(%out, %generified) : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <Int>) -> @out ()
-  dealloc_stack %out : $*()
-  release_value %closure : $@callee_guaranteed () -> Int
-  strong_release %noescapeClosure : $@noescape @callee_guaranteed () -> Int
-  dealloc_stack %appliedThunk : $@noescape @callee_guaranteed () -> @out Int
-  %empty = tuple ()
-  return %empty : $()
-}
-
-sil @testThrowingClosureConvertHelper : $@convention(thin) (Int) -> (Int, @error any Error)
-sil [reabstraction_thunk] @reabstractionThunkThrowing : $@convention(thin) (@noescape @callee_guaranteed () -> (Int, @error any Error)) -> (@out Int, @error any Error)
-
-sil @testClosureThunkNoEscapeThrowing : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>) -> (@out (), @error any Error) {
-entry(%empty : $*(), %closure : $@noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>):
-  %out = alloc_stack $Int
-  try_apply %closure(%out) : $@noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>, normal bb1, error bb2
-
-bb1(%ret : $()):
-  dealloc_stack %out : $*Int
-  store %ret to %empty : $*()
-  %retval = tuple ()
-  return %retval : $()
-
-bb2(%error : $any Error):
-  dealloc_stack %out : $*Int
-  throw %error : $any Error
-}
-
-// CHECK-LABEL: sil @reabstractionThrowing : $@convention(thin) (Int) -> ((), @error any Error) {
-// CHECK:         [[HELPER:%[^,]+]] = function_ref @testThrowingClosureConvertHelper
-// CHECK:         [[SPECIALIZATION:%[^,]+]] = function_ref @$s32testClosureThunkNoEscapeThrowing0afB13ConvertHelperSiTf1nc_n
-// CHECK:         [[CLOSURE:%[^,]+]] = partial_apply [callee_guaranteed] [[HELPER]]
-// CHECK:         [[NOESCAPE_CLOSURE:%[^,]+]] = convert_escape_to_noescape [[CLOSURE]]
-// CHECK:         try_apply [[SPECIALIZATION]]{{.*}}normal [[NORMAL_BLOCK:bb[0-9]+]], error [[ERROR_BLOCK:bb[0-9]+]]
-// CHECK:       [[NORMAL_BLOCK]]
-// CHECK:         release_value [[CLOSURE]]
-// CHECK-NOT:     release_value [[CLOSURE]]
-// CHECK:         strong_release [[NOESCAPE_CLOSURE]]
-// CHECK:       [[ERROR_BLOCK]]
-// CHECK:         release_value [[CLOSURE]]
-// CHECK-NOT:     release_value [[CLOSURE]]
-// CHECK:         strong_release [[NOESCAPE_CLOSURE]]
-// CHECK-LABEL: } // end sil function 'reabstractionThrowing'
-sil @reabstractionThrowing : $(Int) -> ((), @error any Error) {
-bb0(%value : $Int):
-  %testThrowingClosureConvertHelper = function_ref @testThrowingClosureConvertHelper : $@convention(thin) (Int) -> (Int, @error any Error)
-  %closure = partial_apply [callee_guaranteed] %testThrowingClosureConvertHelper(%value) : $@convention(thin) (Int) -> (Int, @error any Error)
-  %noescapeClosure = convert_escape_to_noescape %closure : $@callee_guaranteed () -> (Int, @error any Error) to $@noescape @callee_guaranteed () -> (Int, @error any Error)
-  %thunk = function_ref @reabstractionThunkThrowing : $@convention(thin) (@noescape @callee_guaranteed () -> (Int, @error any Error)) -> (@out Int, @error any Error)
-  %appliedThunk = partial_apply [callee_guaranteed] [on_stack] %thunk(%noescapeClosure) : $@convention(thin) (@noescape @callee_guaranteed () -> (Int, @error any Error)) -> (@out Int, @error any Error)
-
-  %dependency = mark_dependence %appliedThunk : $@noescape @callee_guaranteed () -> (@out Int, @error any Error) on %noescapeClosure : $@noescape @callee_guaranteed () -> (Int, @error any Error)
-  %generified = convert_function %dependency : $@noescape @callee_guaranteed () -> (@out Int, @error any Error) to $@noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>
-  %test = function_ref @testClosureThunkNoEscapeThrowing : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>) -> (@out (), @error any Error)
-  strong_retain %generified : $@noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>
-  %out = alloc_stack $()
-  try_apply %test(%out, %generified) : $@convention(thin) (@owned @noescape @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <Int>) -> (@out (), @error any Error), normal bb1, error bb2
-
-bb1(%ret : $()):
-  dealloc_stack %out : $*()
-  release_value %closure : $@callee_guaranteed () -> (Int, @error any Error)
-  strong_release %noescapeClosure : $@noescape @callee_guaranteed () -> (Int, @error any Error)
-  dealloc_stack %appliedThunk : $@noescape @callee_guaranteed () -> (@out Int, @error any Error)
-  %empty = tuple ()
-  return %empty : $()
-
-bb2(%error : $any Error):
-  dealloc_stack %out : $*()
-  release_value %closure : $@callee_guaranteed () -> (Int, @error any Error)
-  strong_release %noescapeClosure : $@noescape @callee_guaranteed () -> (Int, @error any Error)
-  dealloc_stack %appliedThunk : $@noescape @callee_guaranteed () -> (@out Int, @error any Error)
-  throw %error : $any Error
-}
-
-// Currently not supported cases.
-
-sil @testClosureThunk4 : $@convention(thin) (@owned @callee_guaranteed () -> @out Int) -> @out Int {
-bb0(%0 : $*Int, %1 : $@callee_guaranteed () -> @out Int):
-  apply %1(%0) : $@callee_guaranteed () -> @out Int
-  release_value %1: $@callee_guaranteed () -> @out Int
-  %8 = tuple ()
-  return %8 : $()
-}
-// CHECK-LABEL: sil @reabstractionTest2
-// CHECK: bb0(%0 : $Int):
-// CHECK: [[STK:%.*]] = alloc_stack $Int
-// CHECK: [[F:%.*]] = function_ref @testClosureConvertHelper2
-// CHECK: [[PA:%.*]] = partial_apply [callee_guaranteed] [[F]](%0)
-// CHECK: [[CVT:%.*]] = convert_escape_to_noescape [[PA]]
-// CHECK: [[F2:%.*]] = function_ref @reabstractionThunk
-// CHECK: [[PA2:%.*]] = partial_apply [callee_guaranteed] [[F2]]([[CVT]])
-// CHECK: [[F3:%.*]] = function_ref @testClosureThunk4
-// CHECK:  apply [[F3]]([[STK]], [[PA2]])
-// CHECK:  release_value [[PA]]
-// CHECK:  dealloc_stack [[STK]]
-// CHECK:  return
-
-sil @reabstractionTest2 : $(Int) -> () {
-bb0(%0 : $Int):
-  %48 = alloc_stack $Int
-  %49 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
-  %50 = partial_apply [callee_guaranteed] %49(%0) : $@convention(thin) (Int) -> Int
-  %51 = convert_escape_to_noescape %50 : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
-  %52 = function_ref @reabstractionThunk : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-  %53 = partial_apply [callee_guaranteed] %52(%51) : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-  %55 = function_ref @testClosureThunk4 : $@convention(thin) (@owned @callee_guaranteed () -> @out Int) -> @out Int
-  apply %55(%48, %53) : $@convention(thin) (@owned @callee_guaranteed () -> @out Int) -> @out Int
-  release_value %50: $@callee_guaranteed () -> Int
-  dealloc_stack %48 : $*Int
-  %empty = tuple ()
-  return %empty : $()
-}
-
-// Only support the ultimate partial_apply.
-sil [reabstraction_thunk] @reabstractionThunk2 : $@convention(thin) (@guaranteed @callee_guaranteed () -> Int) -> @out Int
-
-// CHECK-LABEL: sil @reabstractionTest3 : $@convention(thin) (Int) -> () {
-// CHECK: bb0(%0 : $Int):
-// CHECK:  [[STK:%.*]] = alloc_stack $Int
-// CHECK:  [[F:%.*]] = function_ref @testClosureConvertHelper2
-// CHECK:  [[PA:%.*]] = partial_apply [callee_guaranteed] [[F]](%0)
-// CHECK:  [[F2:%.*]] = function_ref @reabstractionThunk2
-// CHECK:  [[SPEC:%.*]] = function_ref @$s25testClosureThunkNoEscape219reabstractionThunk2SiIegd_Tf1nc_n : $@convention(thin) (@owned @callee_guaranteed () -> Int) -> @out Int
-// CHECK:  retain_value [[PA]] : $@callee_guaranteed () -> Int
-// CHECK:  %8 = apply [[SPEC]]([[STK]], [[PA]]) : $@convention(thin) (@owned @callee_guaranteed () -> Int) -> @out Int
-// CHECK:  strong_release [[PA]] : $@callee_guaranteed () -> Int
-// CHECK:  dealloc_stack [[STK]] : $*Int
-// CHECK:  return
-
-sil @reabstractionTest3 : $(Int) -> () {
-bb0(%0 : $Int):
-  %48 = alloc_stack $Int
-  %49 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
-  %50 = partial_apply [callee_guaranteed] %49(%0) : $@convention(thin) (Int) -> Int
-  %52 = function_ref @reabstractionThunk2 : $@convention(thin) (@guaranteed @callee_guaranteed () -> Int) -> @out Int
-  %53 = partial_apply [callee_guaranteed] %52(%50) : $@convention(thin) (@guaranteed @callee_guaranteed () -> Int) -> @out Int
-  %54 = convert_escape_to_noescape %53 : $@callee_guaranteed () -> @out Int to $@noescape @callee_guaranteed () -> @out Int
-  %55 = function_ref @testClosureThunkNoEscape2 : $@convention(thin) (@noescape @callee_guaranteed () -> @out Int) -> @out Int
-  apply %55(%48, %54) : $@convention(thin) (@noescape @callee_guaranteed () -> @out Int) -> @out Int
-  release_value %53: $@callee_guaranteed () -> @out Int
-  dealloc_stack %48 : $*Int
-  %empty = tuple ()
-  return %empty : $()
-}
-
-//////////////////////
-// Begin Apply Test //
-//////////////////////
-
-sil @coroutine_user : $@yield_once @convention(thin) (@noescape @callee_guaranteed () -> Int) -> @yields Int {
-bb0(%0 : $@noescape @callee_guaranteed () -> Int):
-  %1 = apply %0() : $@noescape @callee_guaranteed () -> Int
-  unreachable
-}
-
-// CHECK-LABEL: sil @test_coroutine_user : $@convention(thin) (Int) -> Int {
-// CHECK: [[COROUTINE_USER:%.*]] = function_ref @coroutine_user
-// CHECK: begin_apply [[COROUTINE_USER]](
-// CHECK: } // end sil function 'test_coroutine_user'
-sil @test_coroutine_user : $@convention(thin) (Int) -> Int {
-bb0(%0 : $Int):
-  %1 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
-  %2 = partial_apply [callee_guaranteed] %1(%0) : $@convention(thin) (Int) -> Int
-  %3 = convert_escape_to_noescape %2 : $@callee_guaranteed () -> Int to $@noescape @callee_guaranteed () -> Int
-  %4 = function_ref @coroutine_user : $@yield_once @convention(thin) (@noescape @callee_guaranteed () -> Int) -> @yields Int
-  (%value, %token) = begin_apply %4(%3) : $@yield_once @convention(thin) (@noescape @callee_guaranteed () -> Int) -> @yields Int
-  cond_br undef, bb1, bb2
-
-bb1:
-  end_apply %token as $()
-  br bb3
-
-bb2:
-  abort_apply %token
-  br bb3
-
-bb3:
-  release_value %2 : $@callee_guaranteed () -> Int
-  return %value : $Int
-}
-// CHECK-LABEL: sil @reabstractionTest_on_stack
-// CHECK: bb0([[A:%.*]] : $Int):
-// CHECK:  [[R:%.*]] = alloc_stack $Int
-// CHECK:  [[F:%.*]] = function_ref @$s25testClosureThunkNoEscape20aB14ConvertHelper2SiTf1nc_n
-// CHECK: apply [[F]]([[R]], [[A]])
-sil @reabstractionTest_on_stack : $(Int) -> () {
-bb0(%0 : $Int):
-  %48 = alloc_stack $Int
-  %49 = function_ref @testClosureConvertHelper2 : $@convention(thin) (Int) -> Int
-  %50 = partial_apply [callee_guaranteed] [on_stack] %49(%0) : $@convention(thin) (Int) -> Int
-  %52 = function_ref @reabstractionThunk : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-  %53 = partial_apply [callee_guaranteed] [on_stack] %52(%50) : $@convention(thin) (@noescape @callee_guaranteed () -> Int) -> @out Int
-  %55 = function_ref @testClosureThunkNoEscape2 : $@convention(thin) (@noescape @callee_guaranteed () -> @out Int) -> @out Int
-  apply %55(%48, %53) : $@convention(thin) (@noescape @callee_guaranteed () -> @out Int) -> @out Int
-  dealloc_stack %53 : $@noescape @callee_guaranteed () -> @out Int
-  dealloc_stack %50 : $@noescape @callee_guaranteed () -> Int
-  dealloc_stack %48 : $*Int
-  %empty = tuple ()
-  return %empty : $()
-}
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_and_cfg.sil b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_and_cfg.sil
deleted file mode 100644
index b54d53662ced8..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_and_cfg.sil
+++ /dev/null
@@ -1,49 +0,0 @@
-// RUN: %target-sil-opt -sil-verify-without-invalidation -enable-sil-verify-all -simplify-cfg -experimental-swift-based-closure-specialization %s
-
-// Test if the ClosureSpecializer correctly invalidates the dominator tree
-// even if there are no functions specialized.
-// The test just checks if the compiler does not crash.
-// First running SimplifyCFG creates the dominator tree, which should then be
-// invalidated by the ClosureSpecializer.
-// If this is not done correctly the verification will complain that the
-// dominator tree is not up to date.
-
-import Builtin
-import Swift
-
-sil @closure : $@convention(thin) () -> ()
-
-sil @use_closure : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-
-sil hidden [noinline] @use_closure2 : $@convention(thin) (@owned @callee_owned () -> (), @owned @callee_owned () -> ()) -> () {
-bb0(%0 : $@callee_owned () -> (), %1 : $@callee_owned () -> ()):
-  %2 = apply %0() : $@callee_owned () -> ()
-  %3 = apply %1() : $@callee_owned () -> ()
-  %4 = tuple ()
-  return %3 : $()
-}
-
-sil @insert_release_in_liferange_exit_block : $@convention(thin) () -> () {
-bb0:
-  %2 = function_ref @closure : $@convention(thin) () -> ()
-  %3 = partial_apply %2() : $@convention(thin) () -> ()
-  %8 = function_ref @use_closure : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %5 = partial_apply %8(%3) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-
-  // There is a critical edge from bb0 to bb2 which is broken by ValueLifetimeAnalysis.
-  cond_br undef, bb2, bb1
-
-bb1:
-  strong_retain %3 : $@callee_owned () -> ()
-  strong_retain %3 : $@callee_owned () -> ()
-  %10 = function_ref @use_closure2 : $@convention(thin) (@owned @callee_owned () -> (), @owned @callee_owned () -> ()) -> ()
-
-  // Passing two closures actually prevents closure specialization.
-  %17 = apply %10(%3, %3) : $@convention(thin) (@owned @callee_owned () -> (), @owned @callee_owned () -> ()) -> ()
-  br bb2
-
-bb2:
-  strong_release %5 : $@callee_owned () -> ()
-  %11 = tuple ()
-  return %11 : $()
-}
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_attrs.sil b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_attrs.sil
deleted file mode 100644
index 34222394140be..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_attrs.sil
+++ /dev/null
@@ -1,87 +0,0 @@
-// RUN: %target-sil-opt -enable-sil-verify-all -experimental-swift-based-closure-specialization %s | %FileCheck %s
-// XFAIL: *
-
-import Builtin
-
-class C {}
-
-sil [ossa] @getC : $@convention(thin) () -> @owned C
-
-class Storage {}
-
-struct Val {}
-
-// Verify that the argument to the specialized take_closure is still @_eagerMove.
-
-// CHECK-LABEL: sil {{.*}}@$s12take_closure0B04main1CCTf1nc_n : {{.*}}{
-// CHECK:           {{bb[0-9]+}}({{%[^,]+}} : @_eagerMove @owned $C, {{%[^,]+}} :
-// CHECK-LABEL: } // end sil function '$s12take_closure0B04main1CCTf1nc_n'
-
-sil [ossa] [noinline] @take_closure : $@convention(thin) (@owned C, @guaranteed @noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()) -> () {
-bb0(%c : @_eagerMove @owned $C, %0 : @guaranteed $@noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()):
-  %getC = function_ref @getC : $@convention(thin) () -> @owned C
-  %c1 = apply %getC() : $@convention(thin) () -> @owned C
-  %c2 = apply %getC() : $@convention(thin) () -> @owned C
-  %3 = apply %0(%c1, %c2) : $@noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()
-  destroy_value %c2 : $C
-  destroy_value %c1 : $C
-  destroy_value %c : $C
-  %retval = tuple()
-  return %retval : $()
-}
-
-sil shared [ossa] @closure : $@convention(thin) (@guaranteed C, @guaranteed C, @guaranteed C) -> () {
-bb0(%0 : @guaranteed $C, %1 : @guaranteed $C, %2 : @guaranteed $C):
-  %15 = tuple ()
-  return %15 : $()
-}
-
-sil @caller : $@convention(thin) (@owned C) -> () {
-bb0(%0 : $C):
-  %3 = function_ref @closure : $@convention(thin) (@guaranteed C, @guaranteed C, @guaranteed C) -> ()
-  %4 = partial_apply [callee_guaranteed] [on_stack] %3(%0) : $@convention(thin) (@guaranteed C, @guaranteed C, @guaranteed C) -> ()
-  %take_closure = function_ref @take_closure : $@convention(thin) (@owned C, @guaranteed @noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()) -> ()
-  strong_retain %0 : $C
-  %5 = apply %take_closure(%0, %4) : $@convention(thin) (@owned C, @guaranteed @noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()) -> ()
-  strong_release %0 : $C
-  dealloc_stack %4 : $@noescape @callee_guaranteed (@guaranteed C, @guaranteed C) -> ()
-  %retval = tuple()
-  return %retval : $()
-}
-
-// =============================================================================
-// rdar://105887096: do not insert a retain inside a read-only function.
-// For now, the specialization is disabled.
-//
-// TODO: A @noescape closure should never be converted to an @owned argument
-// regardless of the function attribute.
-
-// This should not be specialized until we support guaranteed arguments.
-// CHECK-NOT: @$s20takesReadOnlyClosure
-sil private [readonly] @takesReadOnlyClosure : $@convention(thin) (@noescape @callee_guaranteed (Val) -> Val) -> Val {
-bb0(%2 : $@noescape @callee_guaranteed (Val) -> Val):
-  %46 = struct $Val ()
-  %261 = apply %2(%46) : $@noescape @callee_guaranteed (Val) -> Val
-  return %261 : $Val
-}
-
-sil private @readOnlyClosure : $@convention(thin) (Val, @guaranteed Storage) -> Val {
-bb0(%0 : $Val, %1 : @closureCapture $Storage):
-  %46 = struct $Val ()
-  return %46 : $Val
-}
-
-// CHECK-LABEL: sil @testPassReadOnlyClosure : $@convention(method) (@guaranteed Storage) -> Val {
-// CHECK-NOT: @owned Storage
-// CHECK: apply %{{.*}} : $@convention(thin) (@noescape @callee_guaranteed (Val) -> Val) -> Val
-// CHECK-LABEL: } // end sil function 'testPassReadOnlyClosure'
-sil @testPassReadOnlyClosure : $@convention(method) (@guaranteed Storage) -> Val {
-bb0(%0 : $Storage):
-  %176 = function_ref @readOnlyClosure : $@convention(thin) (Val, @guaranteed Storage) -> Val
-  %177 = partial_apply [callee_guaranteed] [on_stack] %176(%0) : $@convention(thin) (Val, @guaranteed Storage) -> Val
-  %178 = mark_dependence %177 : $@noescape @callee_guaranteed (Val) -> Val on %0 : $Storage
-  %188 = function_ref @takesReadOnlyClosure : $@convention(thin) (@noescape @callee_guaranteed (Val) -> Val) -> Val
-  %189 = apply %188(%178) : $@convention(thin) (@noescape @callee_guaranteed (Val) -> Val) -> Val
-  dealloc_stack %177 : $@noescape @callee_guaranteed (Val) -> Val
-  return %189 : $Val
-}
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_consolidated.sil b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_consolidated.sil
deleted file mode 100644
index e90d6518408b9..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_consolidated.sil
+++ /dev/null
@@ -1,725 +0,0 @@
-// RUN: %target-sil-opt -enable-sil-verify-all -experimental-swift-based-closure-specialization %s | %FileCheck %s -check-prefix=REMOVECLOSURES
-// RUN: %target-sil-opt -enable-sil-verify-all -closure-specialize-eliminate-dead-closures=0 -experimental-swift-based-closure-specialization %s | %FileCheck %s
-// XFAIL: *
-
-import Builtin
-import Swift
-
-///////////////////
-// Utility Types //
-///////////////////
-
-protocol P {
-  func foo(f: (Int32)->Int32, _ j: Int32) -> Int32
-}
-
-protocol Q {
-}
-
-public class C {
-  @_hasStorage var c: C? { get set }
-  init()
-}
-
-public struct S: Q {
-  @_hasStorage var c: C? { get set }
-  init(c: C?)
-  init()
-}
-
-// = Test Summary =
-// We test the following things here:
-//
-// 1. Address Argument
-// 2. ThinToThick, Partial Apply:
-//   a. with and without removal of closure.
-//   b. @owned and @guaranteed.
-// 3. Bad NonFailureExitBB.
-// 4. No Call in Apply Callee.
-// 5. Non simple closure (i.e. non function_ref closure).
-// 6. Handle interface return types correctly.
-
-////////////////////////////
-// Address Argument Tests //
-////////////////////////////
-//
-// Make sure that we can specialize even if we have address arguments.
-//
-// But we don't handle closures that close over address types passed as @in or
-// @in_guaranteed.
-// (*NOTE* this includes address and non-address only types).
-// This is a temporary limitation.
-// CHECK-LABEL: sil @address_closure : $@convention(thin) (@in Int32) -> () {
-sil @address_closure : $@convention(thin) (@in Int32) -> () {
-bb0(%0 : $*Int32):
-  %6 = tuple()
-  return %6 : $()
-}
-
-sil @address_closure_struct_complex : $@convention(thin) (@in S) -> () {
-bb0(%0 : $*S):
-  %6 = tuple()
-  return %6 : $()
-}
-
-// CHECK-LABEL: sil @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
-sil @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
-bb0(%0 : $@callee_owned () -> ()):
-  %1 = apply %0() : $@callee_owned () -> ()
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// Check that a specialization of address_closure_noescape_user was generated which does not
-// take a closure as a parameter anymore.
-// CHECK-LABEL: sil shared @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
-// CHECK: function_ref @address_closure_trivial : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
-// CHECK: partial_apply %{{.*}} : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
-// CHECK: apply
-// CHECK: return
-
-// Check that a specialization of address_closure_noescape_user was generated which does not
-// take a closure as a parameter anymore.
-// CHECK-LABEL: sil shared @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable Int32) -> ()
-// CHECK: function_ref @address_closure_trivial_mutating : $@convention(thin) (@inout_aliasable Int32) -> ()
-// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable Int32) -> ()
-// CHECK: apply
-// CHECK: return
-
-// Check that a specialization of address_closure_noescape_user was generated which does not
-// take a closure as a parameter anymore.
-// CHECK-LABEL: sil shared @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable any P) -> ()
-// CHECK: function_ref @address_closure_existential : $@convention(thin) (@inout_aliasable any P) -> ()
-// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable any P) -> ()
-// CHECK: apply
-// CHECK: return
-
-// Check that a specialization of address_closure_noescape_user was generated which does not
-// take a closure as a parameter anymore.
-// CHECK-LABEL: sil shared @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-// CHECK: function_ref @address_closure_struct1 : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-// CHECK: apply
-// CHECK: return
-
-// Check that a specialization of address_closure_user was generated which does not
-// take a closure as a parameter anymore.
-// CHECK-LABEL: sil shared @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-// CHECK: function_ref @address_closure_struct2 : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-// CHECK: apply
-// CHECK: return
-
-// Check that a specialization of address_closure_user was generated which does not
-// take a closure as a parameter anymore.
-// CHECK-LABEL: sil shared @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
-// CHECK: function_ref @address_closure_class1 : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
-// CHECK: partial_apply %{{.*}} : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
-// CHECK: apply
-// CHECK: return
-
-// CHECK-LABEL: sil @address_closure_noescape_user : $@convention(thin) (@noescape @callee_owned () -> ()) -> () {
-sil @address_closure_noescape_user : $@convention(thin) (@noescape @callee_owned () -> ()) -> () {
-bb0(%0 : $@noescape @callee_owned () -> ()):
-  %1 = apply %0() : $@noescape @callee_owned () -> ()
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil @address_caller : $@convention(thin) (@in Int32) -> () {
-// CHECK-NOT: _TTSf1cl15address_closureSi__address_closure_user
-sil @address_caller : $@convention(thin) (@in Int32) -> () {
-bb0(%0 : $*Int32):
-  %1 = function_ref @address_closure : $@convention(thin) (@in Int32) -> ()
-  %2 = partial_apply %1(%0) : $@convention(thin) (@in Int32) -> ()
-  %3 = function_ref @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %4 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// We don't handle closures that close over address types passed as @in or
-// @in_guaranteed.
-// (*NOTE* this includes address and non-address only types).
-// This is a temporary limitation.
-//
-// CHECK-LABEL: sil @address_caller_complex : $@convention(thin) (@in Int32) -> ()
-// CHECK-NOT: function_ref @{{.*}}address_closure_user{{.*}} : $@convention(thin) (@in Int32) -> ()
-// CHECK: partial_apply
-// CHECK-NOT: function_ref @{{.*}}address_closure_user{{.*}} : $@convention(thin) (@in Int32) -> ()
-// CHECK: return
-sil @address_caller_complex : $@convention(thin) (@in Int32) -> () {
-bb0(%0 : $*Int32):
-  %00 = alloc_stack $Int32
-  %01 = load %0 : $*Int32
-  store %01 to %00 : $*Int32
-  %1 = function_ref @address_closure : $@convention(thin) (@in Int32) -> ()
-  %2 = partial_apply %1(%00) : $@convention(thin) (@in Int32) -> ()
-  %3 = function_ref @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %4 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  dealloc_stack %00 : $*Int32
-  br bb1
-
-bb1:
-  %6 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// We don't handle closures that close over address types passed as @in or
-// @in_guaranteed.
-// (*NOTE* this includes address and non-address only types).
-// This is a temporary limitation.
-//
-// CHECK-LABEL: sil @address_caller_struct_complex : $@convention(thin) (@in S) -> ()
-// CHECK-NOT:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_user{{.*}} : $@convention(thin) (@in S) -> ()
-// CHECK: partial_apply 
-// CHECK-NOT:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_user{{.*}} : $@convention(thin) (@in S) -> ()
-// CHECK: return
-sil @address_caller_struct_complex : $@convention(thin) (@in S) -> () {
-bb0(%0 : $*S):
-  %00 = alloc_stack $S
-  %01 = load %0 : $*S
-  retain_value %01 : $S
-  store %01 to %00 : $*S
-  %1 = function_ref @address_closure_struct_complex : $@convention(thin) (@in S) -> ()
-  %2 = partial_apply %1(%00) : $@convention(thin) (@in S) -> ()
-  %3 = function_ref @address_closure_user : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %4 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %5  = load %00 : $*S
-  release_value %5 : $S
-  dealloc_stack %00 : $*S
-  br bb1
-
-bb1:
-  %6 = apply %3(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// More complex tests involving address arguments.
-
-sil @address_closure_trivial : $@convention(thin) (Int32, @inout_aliasable Int32) -> () {
-bb0(%0 : $Int32, %1 : $*Int32):
-  %9 = integer_literal $Builtin.Int32, 42
-  %10 = struct $Int32 (%9 : $Builtin.Int32)
-  store %10 to %1 : $*Int32
-  %12 = tuple ()
-  return %12 : $()
-}
-
-// CHECK-LABEL: sil @address_caller_trivial
-// CHECK-NOT: partial_apply
-// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
-// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
-// CHECK-NOT: partial_apply
-// CHECK: return
-sil @address_caller_trivial: $@convention(thin) (Int32) -> Int32 {
-bb0(%0 : $Int32):
-  %2 = alloc_stack $Int32, var, name "xx"
-  store %0 to %2 : $*Int32
-  // function_ref address_closure_noescape_user(f:)
-  %4 = function_ref @address_closure_noescape_user : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  // function_ref address_closure_trivial(x:)
-  %5 = function_ref @address_closure_trivial : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
-  %6 = partial_apply %5(%0, %2) : $@convention(thin) (Int32, @inout_aliasable Int32) -> ()
-  %6b = convert_escape_to_noescape %6 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
-  %7 = apply %4(%6b) : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  %8 = load %2 : $*Int32
-  dealloc_stack %2 : $*Int32
-  return %8 : $Int32
-}
-
-sil @address_closure_trivial_mutating : $@convention(thin) (@inout_aliasable Int32) -> () {
-bb0(%0 : $*Int32):
-  %2 = struct_element_addr %0 : $*Int32, #Int32._value
-  %3 = load %2 : $*Builtin.Int32
-  %4 = integer_literal $Builtin.Int32, 1
-  %5 = integer_literal $Builtin.Int1, -1
-  %6 = builtin "sadd_with_overflow_Int32"(%3 : $Builtin.Int32, %4 : $Builtin.Int32, %5 : $Builtin.Int1) : $(Builtin.Int32, Builtin.Int1)
-  %7 = tuple_extract %6 : $(Builtin.Int32, Builtin.Int1), 0
-  %8 = tuple_extract %6 : $(Builtin.Int32, Builtin.Int1), 1
-  cond_fail %8 : $Builtin.Int1
-  %10 = struct $Int32 (%7 : $Builtin.Int32)
-  store %10 to %0 : $*Int32
-  %12 = tuple ()
-  return %12 : $()
-}
-
-// CHECK-LABEL: sil @address_caller_trivial_mutating
-// CHECK-NOT: partial_apply
-// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable Int32) -> ()
-// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
-// CHECK-NOT: partial_apply
-// CHECK: return
-sil @address_caller_trivial_mutating: $@convention(thin) (Int32) -> Int32 {
-bb0(%0 : $Int32):
-  %2 = alloc_stack $Int32, var, name "xx"
-  store %0 to %2 : $*Int32
-  %4 = function_ref @address_closure_noescape_user : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  %5 = function_ref @address_closure_trivial_mutating : $@convention(thin) (@inout_aliasable Int32) -> ()
-  %6 = partial_apply %5(%2) : $@convention(thin) (@inout_aliasable Int32) -> ()
-  %6b = convert_escape_to_noescape %6 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
-  %7 = apply %4(%6b) : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  %8 = load %2 : $*Int32
-  dealloc_stack %2 : $*Int32
-  return %8 : $Int32
-}
-
-sil @S_init : $@convention(method) (@thin S.Type) -> @owned S
-
-sil hidden @address_closure_body_out_result : $@convention(thin) (@in Q, @in Q) -> @out Q {
-bb0(%0 : $*Q, %1 : $*Q, %2 : $*Q):
-  %5 = init_existential_addr %0 : $*Q, $S
-  // function_ref S.init()
-  %6 = function_ref @S_init : $@convention(method) (@thin S.Type) -> @owned S
-  %7 = metatype $@thin S.Type
-  %8 = apply %6(%7) : $@convention(method) (@thin S.Type) -> @owned S
-  store %8 to %5 : $*S
-  destroy_addr %2 : $*Q
-  destroy_addr %1 : $*Q
-  %12 = tuple ()
-  return %12 : $()
-}
-
-sil @address_closure_out_result : $@convention(thin) (@in Q, @inout_aliasable Q, @inout_aliasable Q) -> @out Q {
-bb0(%0 : $*Q, %1 : $*Q, %2 : $*Q, %3 : $*Q):
-  %7 = function_ref @address_closure_body_out_result : $@convention(thin) (@in Q, @in Q) -> @out Q
-  %8 = alloc_stack $Q
-  copy_addr %2 to [init] %8 : $*Q
-  %10 = alloc_stack $Q
-  copy_addr %3 to [init] %10 : $*Q
-  %12 = apply %7(%0, %8, %10) : $@convention(thin) (@in Q, @in Q) -> @out Q
-  dealloc_stack %10 : $*Q
-  dealloc_stack %8 : $*Q
-  destroy_addr %1 : $*Q
-  %16 = tuple ()
-  return %16 : $()
-}
-
-// Check that a specialization of address_closure_user_out_result was generated which does not
-// take a closure as a parameter anymore.
-// CHECK-LABEL: sil shared @{{.*}}address_closure_user_out_result{{.*}} : $@convention(thin) (@inout_aliasable any Q, @inout_aliasable any Q) -> @out any Q
-// CHECK: function_ref @address_closure_out_result : $@convention(thin) (@in any Q, @inout_aliasable any Q, @inout_aliasable any Q) -> @out any Q
-// CHECK: [[PARTIAL_APPLY:%.*]] = partial_apply %{{.*}} : $@convention(thin) (@in any Q, @inout_aliasable any Q, @inout_aliasable any Q) -> @out any Q
-// CHECK: apply [[PARTIAL_APPLY]]
-// CHECK: return
-
-sil @address_closure_user_out_result : $@convention(thin) (@noescape @callee_owned (@in Q) -> @out Q) -> @out Q {
-bb0(%0 : $*Q, %1 : $@noescape @callee_owned (@in Q) -> @out Q):
-  %4 = alloc_stack $Q
-  %5 = init_existential_addr %4 : $*Q, $S
-  %6 = function_ref @S_init : $@convention(method) (@thin S.Type) -> @owned S
-  %7 = metatype $@thin S.Type
-  %8 = apply %6(%7) : $@convention(method) (@thin S.Type) -> @owned S
-  store %8 to %5 : $*S
-  %10 = apply %1(%0, %4) : $@noescape @callee_owned (@in Q) -> @out Q
-  dealloc_stack %4 : $*Q
-  %13 = tuple ()
-  return %13 : $()
-}
-
-// Check that closure specialization can handle cases where the full closure type may have
-// unsupported address type arguments (e.g. @in or @out), but the partial_apply has only
-// supported address type arguments, i.e. @inout or @inout_aliasable.
-//
-// CHECK-LABEL: sil @address_caller_out_result : $@convention(thin) (@in any Q, @in any Q) -> @out any Q
-// CHECK-NOT: partial_apply
-// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_user_out_result{{.*}} : $@convention(thin) (@inout_aliasable any Q, @inout_aliasable any Q) -> @out any Q
-// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
-// CHECK-NOT: partial_apply
-// CHECK: return
-sil @address_caller_out_result: $@convention(thin) (@in Q, @in Q) -> @out Q {
-bb0(%0 : $*Q, %1 : $*Q, %2 : $*Q):
-  %5 = function_ref @address_closure_user_out_result : $@convention(thin) (@noescape @callee_owned (@in Q) -> @out Q) -> @out Q
-  %6 = function_ref @address_closure_out_result : $@convention(thin) (@in Q, @inout_aliasable Q, @inout_aliasable Q) -> @out Q
-  %7 = partial_apply %6(%1, %2) : $@convention(thin) (@in Q, @inout_aliasable Q, @inout_aliasable Q) -> @out Q 
-  %7b = convert_escape_to_noescape %7 : $@callee_owned (@in Q) -> @out Q to $@noescape @callee_owned (@in Q) -> @out Q
-  %8 = apply %5(%0, %7b) : $@convention(thin) (@noescape @callee_owned (@in Q) -> @out Q) -> @out Q
-  destroy_addr %2 : $*Q
-  destroy_addr %1 : $*Q
-  %11 = tuple ()
-  return %11 : $()
-}
-
-// CHECK-LABEL: sil @address_caller_existential
-// CHECK-NOT: partial_apply
-// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable any P) -> ()
-// CHECK:  [[SPECIALIZED_FN2:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable any P) -> ()
-// CHECK: apply [[SPECIALIZED_FN2]]{{.*}}
-// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
-// CHECK-NOT: partial_apply
-// CHECK: return
-sil @address_caller_existential : $@convention(thin) (@in P, @in P, Int32) -> @out P {
-bb0(%0 : $*P, %1 : $*P, %2 : $*P, %3 : $Int32):
-  %7 = alloc_stack $P
-  copy_addr %1 to [init] %7 : $*P
-  %9 = function_ref @address_closure_existential : $@convention(thin) (@inout_aliasable P) -> ()
-  %10 = partial_apply %9(%7) : $@convention(thin) (@inout_aliasable P) -> ()
-  %10b = convert_escape_to_noescape %10 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
-  %12 = function_ref @address_closure_noescape_user : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  strong_retain %10 : $@callee_owned () -> ()
-  %14 = apply %12(%10b) : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  strong_retain %10 : $@callee_owned () -> ()
-  %16 = apply %12(%10b) : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  %17 = integer_literal $Builtin.Int32, 10
-  %18 = struct_extract %3 : $Int32, #Int32._value
-  %19 = builtin "cmp_slt_Int32"(%17 : $Builtin.Int32, %18 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %19, bb1, bb2
-
-bb1:
-  destroy_addr %2 : $*P
-  copy_addr %1 to [init] %0 : $*P
-  destroy_addr %1 : $*P
-  strong_release %10 : $@callee_owned () -> ()
-  br bb3
-
-bb2:
-  destroy_addr %1 : $*P
-  copy_addr %2 to [init] %0 : $*P
-  destroy_addr %2 : $*P
-  strong_release %10 : $@callee_owned () -> ()
-  br bb3
-
-bb3:
-  destroy_addr %7 : $*P
-  dealloc_stack %7 : $*P
-  %33 = tuple ()
-  return %33 : $()
-}
-
-sil shared @address_closure_existential : $@convention(thin) (@inout_aliasable P) -> () {
-bb0(%0 : $*P):
-  %7 = tuple ()
-  return %7 : $()
-}
-
-sil @address_closure_struct1 : $@convention(thin) (@inout_aliasable S, @owned S) -> () {
-bb0(%0 : $*S, %1 : $S):
-  %4 = struct_element_addr %0 : $*S, #S.c
-  %5 = load %4 : $*Optional<C>
-  store %1 to %0 : $*S
-  release_value %5 : $Optional<C>
-  %8 = tuple ()
-  return %8 : $()
-}
-
-sil @address_closure_struct2 : $@convention(thin) (@inout_aliasable S, @owned S) -> () {
-bb0(%0 : $*S, %1 : $S):
-  %4 = struct_element_addr %0 : $*S, #S.c
-  %5 = load %4 : $*Optional<C>
-  store %1 to %0 : $*S
-  release_value %5 : $Optional<C>
-  %8 = tuple ()
-  return %8 : $()
-}
-
-// CHECK-LABEL: sil @address_caller_struct
-// CHECK-NOT: partial_apply
-// CHECK: [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> () 
-// CHECK: apply [[SPECIALIZED_FN1]]
-// CHECK: [[SPECIALIZED_FN2:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable S, @owned S) -> () 
-// CHECK: apply [[SPECIALIZED_FN2]]
-// CHECK-NOT: partial_apply
-// CHECK: return
-sil @address_caller_struct : $@convention(thin) (@guaranteed S, @guaranteed S) -> @owned S {
-bb0(%0 : $S, %1 : $S):
-  %4 = alloc_stack $S, var, name "xx"
-  %5 = struct_extract %0 : $S, #S.c
-  store %0 to %4 : $*S
-  %7 = function_ref @address_closure_noescape_user : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  %8 = function_ref @address_closure_struct1 : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-  %9 = partial_apply %8(%4, %1) : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-  %9b = convert_escape_to_noescape %9 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
-  retain_value %0 : $S
-  retain_value %1 : $S
-  %12 = apply %7(%9b) : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  %13 = function_ref @address_closure_struct2 : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-  %14 = partial_apply %13(%4, %0) : $@convention(thin) (@inout_aliasable S, @owned S) -> ()
-  %14b = convert_escape_to_noescape %14 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
-  retain_value %5 : $Optional<C>
-  %16 = apply %7(%14b) : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  %17 = load %4 : $*S
-  dealloc_stack %4 : $*S
-  return %17 : $S
-}
-
-sil shared @address_closure_class1 : $@convention(thin) (@inout_aliasable C, @owned C) -> () {
-bb0(%0 : $*C, %1 : $C):
-  %4 = load %0 : $*C
-  store %1 to %0 : $*C
-  strong_release %4 : $C
-  %7 = tuple ()
-  return %7 : $()
-}
-
-// CHECK-LABEL: sil @address_caller_class1
-// CHECK-NOT: partial_apply
-// CHECK:  [[SPECIALIZED_FN1:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
-// CHECK:  [[SPECIALIZED_FN2:%.*]] = function_ref @{{.*}}address_closure_noescape_user{{.*}} : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
-// CHECK: apply [[SPECIALIZED_FN2]]{{.*}}
-// CHECK: apply [[SPECIALIZED_FN1]]{{.*}}
-// CHECK-NOT: partial_apply
-// CHECK: return
-sil @address_caller_class1 : $@convention(thin) (@guaranteed C, @guaranteed C) -> @owned C {
-bb0(%0 : $C, %1 : $C):
-  %4 = alloc_stack $C, var, name "xx"
-  store %0 to %4 : $*C
-  %7 = function_ref @address_closure_class1 : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
-  %8 = partial_apply %7(%4, %1) : $@convention(thin) (@inout_aliasable C, @owned C) -> ()
-  %8b = convert_escape_to_noescape %8 : $@callee_owned () -> () to $@noescape @callee_owned () -> ()
-  %10 = function_ref @address_closure_noescape_user : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  strong_retain %0 : $C
-  strong_retain %1 : $C
-  strong_retain %8 : $@callee_owned () -> ()
-  %14 = apply %10(%8b) : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  strong_retain %8 : $@callee_owned () -> ()
-  %16 = apply %10(%8b) : $@convention(thin) (@noescape @callee_owned () -> ()) -> ()
-  %17 = load %4 : $*C
-  strong_retain %17 : $C
-  strong_release %8 : $@callee_owned () -> ()
-  %20 = load %4 : $*C
-  strong_release %20 : $C
-  dealloc_stack %4 : $*C
-  return %17 : $C
-}
-
-/////////////////////////////////////
-// Thin To Thick and Partial Apply //
-/////////////////////////////////////
-//
-// Make sure that we handle these correctly with and without removal of the
-// closure and @owned and @guaranteed.
-//
-
-// CHECK-LABEL: sil @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-sil @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-bb0(%0 : $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : $Builtin.NativeObject, %3 : $Builtin.NativeObject, %4 : $Builtin.NativeObject, %5 : $Builtin.Int32, %6 : $Builtin.NativeObject, %7 : $Builtin.NativeObject):
-  %9999 = tuple ()
-
-  release_value %2 : $Builtin.NativeObject
-  release_value %6 : $Builtin.NativeObject
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil @small_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-sil @small_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-bb0(%0 : $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : $Builtin.NativeObject, %3 : $Builtin.NativeObject):
-  %9999 = tuple ()
-  release_value %2 : $Builtin.NativeObject
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil shared @$s18owned_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @owned Builtin.NativeObject) -> () {
-// CHECK: bb0
-// CHECK: [[FUN:%.*]] = function_ref @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-// CHECK: [[CLOSURE:%.*]] = partial_apply [[FUN]](
-// CHECK: apply [[CLOSURE]](
-// CHECK: release_value [[CLOSURE]]
-
-// CHECK-LABEL: sil shared @$s18owned_apply_callee014small_closure_C0Tf1cnnnn_n : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-// CHECK: bb0
-// CHECK: [[FUN:%.*]] = function_ref @small_closure_callee
-// CHECK: [[CLOSURE:%.*]] = thin_to_thick_function [[FUN]] : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () to $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-// CHECK: apply [[CLOSURE]](
-// CHECK: release_value [[CLOSURE]]
-
-// CHECK-LABEL: sil @owned_apply_callee : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-sil @owned_apply_callee : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-bb0(%0 : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), %1 : $Builtin.NativeObject, %2 : $Builtin.Int32, %3 : $Builtin.NativeObject, %4 : $Builtin.NativeObject):
-  retain_value %3 : $Builtin.NativeObject
-  apply %0(%1, %2, %3, %4) : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  release_value %3 : $Builtin.NativeObject
-  release_value %0 : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  %9999 = tuple ()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil shared @$s23guaranteed_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @owned Builtin.NativeObject) -> () {
-// CHECK: bb0(%0 : $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : $Builtin.NativeObject, %3 : $Builtin.NativeObject, %4 : $Builtin.NativeObject, %5 : $Builtin.Int32, %6 : $Builtin.NativeObject, %7 : $Builtin.NativeObject):
-// CHECK: [[FUN:%.*]] = function_ref @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-// CHECK: [[CLOSURE:%.*]] = partial_apply [[FUN]](
-// CHECK: apply [[CLOSURE]](
-// CHECK: release_value [[CLOSURE]]
-
-// CHECK-LABEL: sil shared @$s23guaranteed_apply_callee014small_closure_C0Tf1cnnnn_n : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-// CHECK: bb0(%0 : $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : $Builtin.NativeObject, %3 : $Builtin.NativeObject):
-// CHECK: [[FUN:%.*]] = function_ref @small_closure_callee
-// CHECK: [[CLOSURE:%.*]] = thin_to_thick_function [[FUN]] :
-// CHECK: apply [[CLOSURE]](
-// CHECK-NOT: release_value [[CLOSURE]]
-
-// CHECK-LABEL: sil @guaranteed_apply_callee : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-sil @guaranteed_apply_callee : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
-bb0(%0 : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), %1 : $Builtin.NativeObject, %2 : $Builtin.Int32, %3 : $Builtin.NativeObject, %4 : $Builtin.NativeObject):
-  retain_value %3 : $Builtin.NativeObject
-  apply %0(%1, %2, %3, %4) : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  release_value %3 : $Builtin.NativeObject
-  %9999 = tuple ()
-  return %9999 : $()
-}
-sil @guaranteed_apply_callee_throw : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Error) -> @error Error {
-bb0(%0 : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), %1 : $Builtin.NativeObject, %2 : $Builtin.Int32, %3 : $Builtin.NativeObject, %4 : $Builtin.NativeObject, %5: $Error):
-  retain_value %3 : $Builtin.NativeObject
-  apply %0(%1, %2, %3, %4) : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  release_value %3 : $Builtin.NativeObject
-  throw %5 : $Error
-}
-// CHECK-LABEL: sil @thin_thick_and_partial_apply_test : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned any Error) -> () {
-// CHECK: bb0([[ARG0:%.*]] : $Builtin.NativeObject, [[ARG1:%.*]] : $Builtin.Int32, [[ARG2:%.*]] : $Builtin.NativeObject, [[ARG3:%.*]] : $Builtin.NativeObject, [[ARG4:%.*]] : $any Error):
-// CHECK: [[OLD_CLOSURE_CALLEE1:%.*]] = function_ref @large_closure_callee
-// CHECK: [[OLD_CLOSURE_CALLEE2:%.*]] = function_ref @small_closure_callee
-// CHECK: retain_value [[ARG0]] : $Builtin.NativeObject
-// CHECK-NEXT: retain_value [[ARG2]] : $Builtin.NativeObject
-// CHECK-NEXT: retain_value [[ARG3]] : $Builtin.NativeObject
-// CHECK: [[SPECFUN0:%.*]] = function_ref @$s23guaranteed_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n
-// CHECK: retain_value [[ARG0]] : $Builtin.NativeObject
-// CHECK-NEXT: retain_value [[ARG2]] : $Builtin.NativeObject
-// CHECK-NEXT: retain_value [[ARG3]] : $Builtin.NativeObject
-// CHECK: [[SPECFUN1:%.*]] = function_ref @$s18owned_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n
-// CHECK: retain_value [[ARG0]] : $Builtin.NativeObject
-// CHECK-NEXT: retain_value [[ARG2]] : $Builtin.NativeObject
-// CHECK-NEXT: retain_value [[ARG3]] : $Builtin.NativeObject
-// CHECK: [[DEAD_CLOSURE_1:%.*]] = partial_apply [[OLD_CLOSURE_CALLEE1]]
-// CHECK: [[SPECFUN2:%.*]] = function_ref @$s23guaranteed_apply_callee014small_closure_C0Tf1cnnnn_n 
-// CHECK: [[SPECFUN3:%.*]] = function_ref @$s18owned_apply_callee014small_closure_C0Tf1cnnnn_n
-// CHECK: [[DEAD_CLOSURE_2:%.*]] = thin_to_thick_function [[OLD_CLOSURE_CALLEE2]]
-// CHECK: retain_value [[DEAD_CLOSURE_1]]
-// CHECK-NOT: retain_value [[DEAD_CLOSURE_2]]
-// CHECK-NOT: apply [[DEAD_CLOSURE_1]]
-// CHECK-NOT: apply [[DEAD_CLOSURE_2]]
-// CHECK: apply [[SPECFUN1]](
-// CHECK-NEXT: release_value [[DEAD_CLOSURE_1]]
-// CHECK-NOT: release_value [[DEAD_CLOSURE_2]]
-// CHECK: apply [[SPECFUN3]](
-// CHECK-NOT: release_value [[DEAD_CLOSURE_1]]
-// CHECK-NOT: release_value [[DEAD_CLOSURE_2]]
-// CHECK: apply [[SPECFUN0]](
-// CHECK-NOT: release_value [[DEAD_CLOSURE_1]]
-// CHECK-NOT: release_value [[DEAD_CLOSURE_2]]
-// CHECK: apply [[SPECFUN2]](
-// CHECK-NEXT: release_value [[DEAD_CLOSURE_1]]
-// CHECK-NOT: release_value [[DEAD_CLOSURE_2]]
-
-// REMOVECLOSURES-LABEL: sil @thin_thick_and_partial_apply_test : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned any Error) -> () {
-// REMOVECLOSURES: bb0([[ARG0:%.*]] : $Builtin.NativeObject, [[ARG1:%.*]] : $Builtin.Int32, [[ARG2:%.*]] : $Builtin.NativeObject, [[ARG3:%.*]] : $Builtin.NativeObject, [[ARG4:%.*]] : $any Error):
-// REMOVECLOSURES: [[OLD_CLOSURE_CALLEE1:%.*]] = function_ref @large_closure_callee
-// REMOVECLOSURES: [[OLD_CLOSURE_CALLEE2:%.*]] = function_ref @small_closure_callee
-// REMOVECLOSURES: retain_value [[ARG0]] : $Builtin.NativeObject
-// REMOVECLOSURES-NEXT: retain_value [[ARG2]] : $Builtin.NativeObject
-// REMOVECLOSURES-NEXT: retain_value [[ARG3]] : $Builtin.NativeObject
-// REMOVECLOSURES: [[SPECFUN0:%.*]] = function_ref @$s23guaranteed_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n
-// REMOVECLOSURES: retain_value [[ARG0]] : $Builtin.NativeObject
-// REMOVECLOSURES-NEXT: retain_value [[ARG2]] : $Builtin.NativeObject
-// REMOVECLOSURES-NEXT: retain_value [[ARG3]] : $Builtin.NativeObject
-// REMOVECLOSURES: [[SPECFUN1:%.*]] = function_ref @$s18owned_apply_callee014large_closure_C0BoBi32_BoBoTf1cnnnn_n
-// REMOVECLOSURES: retain_value [[ARG0]] : $Builtin.NativeObject
-// REMOVECLOSURES-NEXT: retain_value [[ARG2]] : $Builtin.NativeObject
-// REMOVECLOSURES-NEXT: retain_value [[ARG3]] : $Builtin.NativeObject
-// REMOVECLOSURES-NOT: partial_apply [[OLD_CLOSURE_CALLEE1]]
-// REMOVECLOSURES: [[SPECFUN4:%.*]] = function_ref @$s29guaranteed_apply_callee_throw014small_closure_C0Tf1cnnnnn_n
-// REMOVECLOSURES: [[SPECFUN2:%.*]] = function_ref @$s23guaranteed_apply_callee014small_closure_C0Tf1cnnnn_n
-// REMOVECLOSURES: [[SPECFUN3:%.*]] = function_ref @$s18owned_apply_callee014small_closure_C0Tf1cnnnn_n
-// REMOVECLOSURES-NOT: thin_to_thick_function [[OLD_CLOSURE_CALLEE2]]
-// REMOVECLOSURES: apply [[SPECFUN1]](
-// REMOVECLOSURES-NEXT: apply [[SPECFUN3]](
-// REMOVECLOSURES-NEXT: apply [[SPECFUN0]](
-// REMOVECLOSURES-NEXT: apply [[SPECFUN2]](
-// REMOVECLOSURES-NEXT: strong_release [[ARG0]] : $Builtin.NativeObject
-// REMOVECLOSURES-NEXT: strong_release [[ARG2]] : $Builtin.NativeObject
-// REMOVECLOSURES-NEXT: strong_release [[ARG3]] : $Builtin.NativeObject
-// REMOVECLOSURES-NEXT: try_apply [[SPECFUN4]](
-sil @thin_thick_and_partial_apply_test : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Error) -> () {
-bb0(%0 : $Builtin.NativeObject, %1 : $Builtin.Int32, %2 : $Builtin.NativeObject, %3 : $Builtin.NativeObject, %11: $Error):
-  %4 = function_ref @owned_apply_callee : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  %5 = function_ref @guaranteed_apply_callee : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  %6 = function_ref @large_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  %7 = function_ref @small_closure_callee : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  %10 = function_ref @guaranteed_apply_callee_throw : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Error) -> @error Error
-
-  retain_value %0 : $Builtin.NativeObject
-  retain_value %2 : $Builtin.NativeObject
-  retain_value %3 : $Builtin.NativeObject
-  %8 = partial_apply %6(%0, %1, %2, %3) : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  %9 = thin_to_thick_function %7 : $@convention(thin) (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () to $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-
-  retain_value %8 : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  apply %4(%8, %0, %1, %2, %3) : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  apply %4(%9, %0, %1, %2, %3) : $@convention(thin) (@owned @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  apply %5(%8, %0, %1, %2, %3) : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  apply %5(%9, %0, %1, %2, %3) : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-
-  release_value %8 : $@callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> ()
-  try_apply %10(%9, %0, %1, %2, %3, %11) : $@convention(thin) (@guaranteed @callee_owned (Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> (), Builtin.NativeObject, Builtin.Int32, @owned Builtin.NativeObject, @guaranteed Builtin.NativeObject, @owned Error) -> @error Error, normal bb2, error bb3
-
-bb2(%n : $()):
-  br bb4
-
-bb3(%e : $Error):
-  br bb4
-
-bb4:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-//////////////////////////////
-// Non Function Ref Closure //
-//////////////////////////////
-//
-// Make sure we do not try to specialize a closure if we are not closing over a
-// direct function ref.
-
-// CHECK-LABEL: @$s4test3barSiAA1P_p_SitF : $@convention(thin) (@in any P, Int32) -> Int32 {
-// CHECK: partial_apply
-// CHECK: apply
-sil [noinline] @$s4test3barSiAA1P_p_SitF : $@convention(thin) (@in P, Int32) -> Int32 {
-bb0(%0 : $*P, %1 : $Int32):
-  %2 = open_existential_addr mutable_access %0 : $*P to $*@opened("01234567-89ab-cdef-0123-000000000000", P) Self
-  %3 = witness_method $@opened("01234567-89ab-cdef-0123-000000000000", P) Self, #P.foo, %2 : $*@opened("01234567-89ab-cdef-0123-000000000000", P) Self : $@convention(witness_method: P) @callee_owned <T: P> (@callee_owned (Int32) -> Int32, Int32, @inout T) -> Int32
-  %4 = integer_literal $Builtin.Int32, 2
-  %5 = struct $Int32 (%4 : $Builtin.Int32)
-  // function_ref test.baz (Swift.Int32)(m : Swift.Int32) -> Swift.Int32
-  %6 = function_ref @$s4test3bazSiSi1m_tcSiF : $@convention(thin) (Int32, Int32) -> Int32
-  %7 = partial_apply %6(%5) : $@convention(thin) (Int32, Int32) -> Int32
-  %8 = apply %3<@opened("01234567-89ab-cdef-0123-000000000000", P) Self>(%7, %1, %2) : $@convention(witness_method: P) @callee_owned <T: P> (@callee_owned (Int32) -> Int32, Int32, @inout T) -> Int32
-  destroy_addr %0 : $*P
-  return %8 : $Int32
-}
-
-sil @$s4test3bazSiSi1m_tcSiF : $@convention(thin) (Int32, Int32) -> Int32
-
-//////////////////////////////////////////////////////////////////////////////////
-// Make sure that we properly set a specialized closure's indirect return type. //
-//////////////////////////////////////////////////////////////////////////////////
-//
-// SIL verification should catch the incorrect type.
-// rdar:://19321284
-
-// CHECK-LABEL: sil [serialized] @callee : $@convention(thin) (Builtin.Int32) -> () {
-sil [serialized] @callee : $@convention(thin) (Builtin.Int32) -> () {
-bb0(%0 : $Builtin.Int32):
-  unreachable
-}
-
-sil shared [serialized] @thunk : $@convention(thin) (@callee_owned () -> ()) -> @out () {
-bb0(%0 : $*(), %1 : $@callee_owned () -> ()):
-  apply %1() : $@callee_owned () -> ()
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: @test_closure_propagation : $@convention(thin) () -> () {
-// REMOVECLOSURES-LABEL: @test_closure_propagation : $@convention(thin) () -> () {
-// REMOVECLOSURES-NOT: partial_apply
-sil [serialized] @test_closure_propagation : $@convention(thin) () -> () {
-bb0:
-  %f1 = function_ref @callee : $@convention(thin) (Builtin.Int32) -> ()
-  %i1 = integer_literal $Builtin.Int32, 24
-  %p1 = partial_apply %f1(%i1) : $@convention(thin) (Builtin.Int32) -> ()
-  %f2 = function_ref @thunk : $@convention(thin) (@callee_owned () -> ()) -> @out ()
-  %s1 = alloc_stack $()
-  %a1 = apply %f2(%s1, %p1) : $@convention(thin) (@callee_owned () -> ()) -> @out ()
-  dealloc_stack %s1 : $*()
-  unreachable
-}
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_dynamic_self.swift b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_dynamic_self.swift
deleted file mode 100644
index 4e304127aa1f6..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_dynamic_self.swift
+++ /dev/null
@@ -1,23 +0,0 @@
-// RUN: %target-swift-frontend -emit-sil -O -experimental-swift-based-closure-specialization -primary-file %s
-
-// Just make sure we skip the optimization and not crash here.
-//
-// Eventually, we can make this work.
-//
-// <rdar://problem/31725007>
-
-class Foo {
-  required init() {}
-
-  static func foo(_ f: () -> ()) -> Self {
-    f()
-    return self.init()
-  }
-}
-
-class Bar: Foo {}
-
-func closures(_ x: String) {
-  print(Foo.foo { _ = x })
-  print(Bar.foo { _ = x })
-}
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_fragile.sil b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_fragile.sil
deleted file mode 100644
index bf808aafadc10..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_fragile.sil
+++ /dev/null
@@ -1,60 +0,0 @@
-// RUN: %target-sil-opt  %s -verify -experimental-swift-based-closure-specialization -o -  | %FileCheck %s
-
-// Make sure we do not specialize resilientCallee.
-
-sil_stage canonical
-
-import Builtin
-import Swift
-import SwiftShims
-
-@_optimize(none) public func action()
-
-@inline(__always) public func fragileCaller()
-
-public func resilientCallee(fn: () -> ())
-
-// action()
-sil [Onone] @$s26closure_specialize_fragile6actionyyF : $@convention(thin) () -> () {
-bb0:
-  %0 = tuple ()
-  return %0 : $()
-} // end sil function '$s26closure_specialize_fragile6actionyyF'
-
-// CHECK-LABEL: sil [serialized] [always_inline] @$s26closure_specialize_fragile0C6CalleryyF : $@convention(thin) () -> ()
-// CHECK: function_ref @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-// CHECK: return
-// fragileCaller()
-sil [serialized] [always_inline] @$s26closure_specialize_fragile0C6CalleryyF : $@convention(thin) () -> () {
-bb0:
-  // function_ref resilientCallee(fn:)
-  %0 = function_ref @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  // function_ref closure #1 in fragileCaller()
-  %1 = function_ref @$s26closure_specialize_fragile0C6CalleryyFyycfU_ : $@convention(thin) () -> () 
-  %2 = thin_to_thick_function %1 : $@convention(thin) () -> () to $@callee_owned () -> () 
-  %3 = apply %0(%2) : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-  %4 = tuple ()
-  return %4 : $()
-} // end sil function '$s26closure_specialize_fragile0C6CalleryyF'
-
-// CHECK-LABEL: sil @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> ()
-
-// resilientCallee(fn:)
-sil @$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF : $@convention(thin) (@owned @callee_owned () -> ()) -> () {
-bb0(%0 : $@callee_owned () -> ()):
-  strong_retain %0 : $@callee_owned () -> ()
-  %3 = apply %0() : $@callee_owned () -> ()
-  strong_release %0 : $@callee_owned () -> ()
-  %5 = tuple ()
-  return %5 : $()
-} // end sil function '$s26closure_specialize_fragile15resilientCalleeyyyc2fn_tF'
-
-// closure #1 in fragileCaller()
-sil shared [serialized] @$s26closure_specialize_fragile0C6CalleryyFyycfU_ : $@convention(thin) () -> () {
-bb0:
-  // function_ref action()
-  %0 = function_ref @$s26closure_specialize_fragile6actionyyF : $@convention(thin) () -> () 
-  %1 = apply %0() : $@convention(thin) () -> ()
-  %2 = tuple ()
-  return %2 : $()
-} // end sil function '$s26closure_specialize_fragile0C6CalleryyFyycfU_'
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_loop.swift b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_loop.swift
deleted file mode 100644
index a5eb9a228e660..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_loop.swift
+++ /dev/null
@@ -1,81 +0,0 @@
-// RUN: %{python} %S/../Inputs/timeout.py 10 %target-swift-frontend -O -parse-as-library -experimental-swift-based-closure-specialization %s -emit-sil | %FileCheck %s
-// XFAIL: *
-public func callit() {
-    testit { false }
-}
-
-// Check if the compiler terminates and does not full into an infinite optimization
-// loop between the ClosureSpecializer and CapturePropagation.
-
-// CHECK-LABEL: sil @$s23closure_specialize_loop6testit1cySbyc_tF
-public func testit(c: @escaping () -> Bool) {
-  if c() {
-    testit { !c() }
-  }
-}
-
-// PR: https://github.com/apple/swift/pull/61956
-// Optimizing Expression.contains(where:) should not timeout.
-//
-// Repeated capture propagation leads to:
-//   func contains$termPred@arg0$[termPred$falsePred@arg1]@arg1(expr) {
-//     closure = termPred$[termPred$falsePred@arg1]@arg1
-//     falsePred(expr)
-//     contains$termPred@arg0$termPred$[termPred$falsePred@arg1]@arg1(expr)
-//   }
-//
-//   func contains$termPred@arg0$termPred$[termPred$falsePred@arg1]@arg1(expr) {
-//   closure = [termPred(termPred$[termPred$falsePred@arg1]@arg1)]
-//   closure(expr)
-//   contains$termPred@arg0(expr, closure)
-// }
-// The Demangled type tree looks like:
-//   kind=FunctionSignatureSpecialization
-//     kind=SpecializationPassID, index=3
-//     kind=FunctionSignatureSpecializationParam
-//     kind=FunctionSignatureSpecializationParam
-//       kind=FunctionSignatureSpecializationParamKind, index=0
-//       kind=FunctionSignatureSpecializationParamPayload, text="$s4test10ExpressionO8contains5whereS3bXE_tFSbACXEfU_S2bXEfU_36$s4test12IndirectEnumVACycfcS2bXEfU_Tf3npf_n"
-//
-// CHECK-LABEL: $s23closure_specialize_loop10ExpressionO8contains5whereS3bXE_tFSbACXEfU_S2bXEfU_012$s23closure_b7_loop10d44O8contains5whereS3bXE_tFSbACXEfU_S2bXEfU_012g13_b7_loop10d44ijk2_tlm2U_no52U_012g30_B34_loop12IndirectEnumVACycfcnO10U_Tf3npf_nY2_nTf3npf_n
-// ---> function signature specialization
-//     <Arg[1] = [Constant Propagated Function : function signature specialization
-//                <Arg[1] = [Constant Propagated Function : function signature specialization
-//                           <Arg[1] = [Constant Propagated Function : closure #1 (Swift.Bool) -> Swift.Bool
-//                                      in closure_specialize_loop.IndirectEnum.init() -> closure_specialize_loop.IndirectEnum]>
-//                           of closure #1 (Swift.Bool) -> Swift.Bool
-//                           in closure #1 (closure_specialize_loop.Expression) -> Swift.Bool
-//                           in closure_specialize_loop.Expression.contains(where: (Swift.Bool) -> Swift.Bool) -> Swift.Bool]>
-//                of closure #1 (Swift.Bool) -> Swift.Bool
-//                in closure #1 (closure_specialize_loop.Expression) -> Swift.Bool
-//                in closure_specialize_loop.Expression.contains(where: (Swift.Bool) -> Swift.Bool) -> Swift.Bool]>
-//     of closure #1 (Swift.Bool) -> Swift.Bool
-//     in closure #1 (closure_specialize_loop.Expression) -> Swift.Bool
-//     in closure_specialize_loop.Expression.contains(where: (Swift.Bool) -> Swift.Bool) -> Swift.Bool
-//
-public indirect enum Expression {
-    case term(Bool)
-    case list(_ expressions: [Expression])
-
-    public func contains(where predicate: (Bool) -> Bool) -> Bool {
-        switch self {
-        case let .term(term):
-            return predicate(term)
-        case let .list(expressions):
-            return expressions.contains { expression in
-                expression.contains { term in
-                    predicate(term)
-                }
-            }
-        }
-    }
-}
-
-public struct IndirectEnum {
-    public init() {
-        let containsFalse = Expression.list([.list([.term(true), .term(false)]), .term(true)]).contains { term in
-            term == false
-        }
-        print(containsFalse)
-    }
-}
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_opaque.sil b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_opaque.sil
deleted file mode 100644
index 149e7c3044711..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_opaque.sil
+++ /dev/null
@@ -1,43 +0,0 @@
-// RUN: %target-sil-opt -enable-sil-opaque-values -enable-sil-verify-all -experimental-swift-based-closure-specialization %s | %FileCheck %s
-// XFAIL: *
-
-struct TestView {}
-struct TestRange {}
-struct TestSlice {}
-
-// helper
-sil @closure : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> () {
-bb0(%0 : $*TestView, %1 : $TestRange, %2 : $TestSlice):
-  %1284 = tuple ()
-  return %1284 : $()
-}
-
-// helper
-sil @thunk : $@convention(thin) (@inout TestView, @owned @callee_owned (@inout TestView) -> ()) -> @out () {
-bb0(%0 : $*TestView, %1 : $@callee_owned (@inout TestView) ->()):
-  %call = apply %1(%0) : $@callee_owned (@inout TestView) -> ()
-  %1284 = tuple ()
-  return %1284 : $()
-}
-
-// Test that ClosureSpecializer can handle captured @in args, in addition to direct args.
-//
-// CHECK-LABEL: sil @testSpecializeThunk : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> () {
-// CHECK: bb0(%0 : $*TestView, %1 : $TestRange, %2 : $TestSlice):
-// CHECK:   [[CLOSURE:%.*]] = function_ref @closure : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> ()
-// CHECK:   [[SPECIALIZED:%.*]] = function_ref @$s5thunk7closure4main9TestRangeVAC0D5SliceVTf1nc_n : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> @out () // user: %6
-// CHECK:   [[THUNK:%.*]] = function_ref @thunk : $@convention(thin) (@inout TestView, @owned @callee_owned (@inout TestView) -> ()) -> @out ()
-// CHECK:   [[CALL:%.*]] = apply [[SPECIALIZED]](%0, %1, %2) : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> @out ()
-// CHECK:   %{{.*}} = tuple ()
-// CHECK:   return %{{.*}} : $()
-// CHECK-LABEL: } // end sil function 'testSpecializeThunk'
-sil @testSpecializeThunk : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> () {
-bb0(%0 : $*TestView, %1 : $TestRange, %2 : $TestSlice):
-  %closurefn = function_ref @closure : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> ()
-  %pa = partial_apply %closurefn(%1, %2) : $@convention(thin) (@inout TestView, TestRange, @in TestSlice) -> ()
-  %thunk = function_ref @thunk : $@convention(thin) (@inout TestView, @owned @callee_owned (@inout TestView) -> ()) -> @out ()
-  strong_retain %pa : $@callee_owned (@inout TestView) -> ()
-  %call = apply %thunk(%0, %pa) : $@convention(thin) (@inout TestView, @owned @callee_owned (@inout TestView) -> ()) -> @out ()
-  %1284 = tuple ()
-  return %1284 : $()
-}
diff --git a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_simple.sil b/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_simple.sil
deleted file mode 100644
index 42d91710ae3db..0000000000000
--- a/test/SILOptimizer/experimental-swift-based-closure-specialization/closure_specialize_simple.sil
+++ /dev/null
@@ -1,292 +0,0 @@
-// RUN: %target-sil-opt -enable-sil-verify-all -experimental-swift-based-closure-specialization %s | %FileCheck %s
-// XFAIL: *
-
-import Builtin
-import Swift
-
-sil @simple_partial_apply_fun : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
-
-// CHECK-LABEL: sil shared @$s27simple_partial_apply_caller0a1_b1_C4_funBi1_Tf1c_n : $@convention(thin) (Builtin.Int1) -> Builtin.Int1 {
-// CHECK: bb0([[CAPTURED_ARG:%.*]] : $Builtin.Int1):
-// CHECK: [[CLOSED_OVER_FUN:%.*]] = function_ref @simple_partial_apply_fun :
-// CHECK: [[NEW_PAI:%.*]] = partial_apply [[CLOSED_OVER_FUN]]
-// CHECK: strong_release [[NEW_PAI]]
-sil @simple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1 {
-bb0(%0 : $@callee_owned (Builtin.Int1) -> Builtin.Int1):
-  br bb1
-
-bb1:
-  %1 = integer_literal $Builtin.Int1, 0
-  // We cannot do anything here for now but in the future I think we should try
-  // to handle this in closure specialization potentially.
-  %2 = apply %0(%1) : $@callee_owned (Builtin.Int1) -> Builtin.Int1
-  strong_release %0 : $@callee_owned (Builtin.Int1) -> Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  return %2 : $Builtin.Int1
-}
-
-// CHECK-LABEL: sil shared @$s37simple_partial_apply_2nd_level_caller0a1_b1_C4_funBi1_Tf1c_n : $@convention(thin) (Builtin.Int1) -> Builtin.Int1 {
-// CHECK: bb0([[CAPTURED_ARG:%.*]] : $Builtin.Int1):
-// CHECK: [[SPECIALIZED_CALLEE:%.*]] = function_ref @$s27simple_partial_apply_caller0a1_b1_C4_funBi1_Tf1c_n  :
-// CHECK: [[RET:%.*]]= apply [[SPECIALIZED_CALLEE]]([[CAPTURED_ARG]])
-// CHECK: return [[RET]]
-sil @simple_partial_apply_2nd_level_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1 {
-bb0(%0 : $@callee_owned (Builtin.Int1) -> Builtin.Int1):
-  br bb1
-
-bb1:
-  %1 = function_ref @simple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-  %2 = apply %1(%0) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  return %2 : $Builtin.Int1
-}
-sil @simple_partial_apply_caller_decl : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-
-sil @simple_multiple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1, @owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1 {
-bb0(%0 : $@callee_owned (Builtin.Int1) -> Builtin.Int1, %1 : $@callee_owned (Builtin.Int1) -> Builtin.Int1):
-  br bb1
-
-bb1:
-  %2 = integer_literal $Builtin.Int1, 0
-  // We cannot do anything here for now but in the future I think we should try
-  // to handle this in closure specialization potentially.
-  apply %0(%2) : $@callee_owned (Builtin.Int1) -> Builtin.Int1
-  strong_release %0 : $@callee_owned (Builtin.Int1) -> Builtin.Int1
-  apply %1(%2) : $@callee_owned (Builtin.Int1) -> Builtin.Int1
-  strong_release %1 : $@callee_owned (Builtin.Int1) -> Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  return %2 : $Builtin.Int1
-}
-
-sil @simple_partial_apply_fun2 : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
-sil @simple_partial_apply_caller2 : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1 {
-bb0(%0 : $@callee_owned (Builtin.Int1) -> Builtin.Int1):
-  br bb1
-
-bb1:
-  %1 = integer_literal $Builtin.Int1, 0
-  // We cannot do anything here for now but in the future I think we should try
-  // to handle this in closure specialization potentially.
-  %2 = apply %0(%1) : $@callee_owned (Builtin.Int1) -> Builtin.Int1
-  strong_release %0 : $@callee_owned (Builtin.Int1) -> Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  return %2 : $Builtin.Int1
-}
-
-
-sil @indirect_parameter_partial_apply_fun : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
-
-sil @indirect_parameter_partial_apply_caller1 : $@convention(thin) (@callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1) -> () {
-bb0(%0 : $@callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1):
-  br bb1
-
-bb1:
-  %1 = alloc_stack $Builtin.Int1
-  %2 = integer_literal $Builtin.Int1, 0
-  apply %0(%1, %1, %2, %1) : $@callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
-  dealloc_stack %1 : $*Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-sil @indirect_parameter_partial_apply_caller2 : $@convention(thin) (@callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1) -> () {
-bb0(%0 : $@callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1):
-  br bb1
-
-bb1:
-  %1 = alloc_stack $Builtin.Int1
-  %2 = integer_literal $Builtin.Int1, 0
-  apply %0(%1, %1, %2) : $@callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1
-  dealloc_stack %1 : $*Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-sil @indirect_parameter_partial_apply_caller3 : $@convention(thin) (@callee_owned (@in Builtin.Int1) -> @out Builtin.Int1) -> () {
-bb0(%0 : $@callee_owned (@in Builtin.Int1) -> @out Builtin.Int1):
-  br bb1
-
-bb1:
-  %1 = alloc_stack $Builtin.Int1
-  apply %0(%1, %1) : $@callee_owned (@in Builtin.Int1) -> @out Builtin.Int1
-  dealloc_stack %1 : $*Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-sil @indirect_parameter_partial_apply_caller4 : $@convention(thin) (@callee_owned () -> @out Builtin.Int1) -> () {
-bb0(%0 : $@callee_owned () -> @out Builtin.Int1):
-  br bb1
-
-bb1:
-  %1 = alloc_stack $Builtin.Int1
-  apply %0(%1) : $@callee_owned () -> @out Builtin.Int1
-  dealloc_stack %1 : $*Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-sil @indirect_parameter_partial_apply_caller5 : $@convention(thin) (@callee_owned () -> ()) -> () {
-bb0(%0 : $@callee_owned () -> ()):
-  br bb1
-
-bb1:
-  apply %0() : $@callee_owned () -> ()
-  cond_br undef, bb1, bb2
-
-bb2:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-sil @indirect_parameter_partial_apply_caller6 : $@convention(thin) (@callee_owned () -> @out Builtin.Int1) -> @out Builtin.Int1 {
-bb0(%1 : $*Builtin.Int1, %0 : $@callee_owned () -> @out Builtin.Int1):
-  br bb1
-
-bb1:
-  apply %0(%1) : $@callee_owned () -> @out Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-sil @indirect_parameter_partial_apply_caller7 : $@convention(thin) (@callee_owned () -> @out Builtin.Int1) -> @out (Builtin.Int1, Builtin.Int1) {
-bb0(%1 : $*(Builtin.Int1, Builtin.Int1), %0 : $@callee_owned () -> @out Builtin.Int1):
-  br bb1
-
-bb1:
-  %2 = alloc_stack $Builtin.Int1
-  %3 = alloc_stack $Builtin.Int1
-  apply %0(%2) : $@callee_owned () -> @out Builtin.Int1
-  apply %0(%3) : $@callee_owned () -> @out Builtin.Int1
-  %4 = load %2: $*Builtin.Int1
-  %5 = load %3: $*Builtin.Int1
-  %6 = tuple(%4 : $Builtin.Int1, %5: $Builtin.Int1)
-  store %6 to %1 : $*(Builtin.Int1, Builtin.Int1)
-  dealloc_stack %3: $*Builtin.Int1
-  dealloc_stack %2: $*Builtin.Int1
-  cond_br undef, bb1, bb2
-
-bb2:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil @loop_driver : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> () {
-// CHECK-DAG: [[SPECIALIZED_FUN:%.*]] = function_ref @$s27simple_partial_apply_caller0a1_b1_C4_funBi1_Tf1c_n : $@convention(thin) (Builtin.Int1) -> Builtin.Int1
-// CHECK-DAG: [[SPECIALIZED_FUN2:%.*]] = function_ref @$s37simple_partial_apply_2nd_level_caller0a1_b1_C4_funBi1_Tf1c_n : $@convention(thin) (Builtin.Int1) -> Builtin.Int1
-// CHECK: apply [[SPECIALIZED_FUN]]
-// CHECK: apply [[SPECIALIZED_FUN2]]
-
-// We can't call this one b/c it is just a declaration.
-// CHECK: [[UNSPECIALIZED_FUN_DECL:%.*]] = function_ref @simple_partial_apply_caller_decl : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-// CHECK: apply [[UNSPECIALIZED_FUN_DECL]]
-
-// We handle closures with indirect results.
-// CHECK: [[CLOSUREFUN:%.*]] = function_ref @indirect_parameter_partial_apply_fun
-// CHECK-NOT: partial_apply [[CLOSUREFUN]]()
-// CHECK: [[INLINEDCLOSURE_CALLER1:%.*]] = function_ref @$s40indirect_parameter_partial_apply_caller10a1_b1_c1_D4_funTf1c_n
-// CHECK-NOT: partial_apply [[CLOSUREFUN]]()
-
-// We don't handle captured indirect @in and @in_guaranteed parameters yet.
-// CHECK: [[CLOSURE2:%.*]] = partial_apply [[CLOSUREFUN]](%{{.*}})
-// CHECK: [[CLOSURE3:%.*]] = partial_apply [[CLOSUREFUN]](%{{.*}})
-// CHECK: [[CLOSURE4:%.*]] = partial_apply [[CLOSUREFUN]](%{{.*}})
-
-// CHECK:  [[CALLER1:%.*]] = function_ref @indirect_parameter_partial_apply_caller1
-// CHECK:  [[CALLER2:%.*]] = function_ref @indirect_parameter_partial_apply_caller2
-// CHECK:  [[CALLER3:%.*]] = function_ref @indirect_parameter_partial_apply_caller3
-// CHECK:  [[CALLER4:%.*]] = function_ref @indirect_parameter_partial_apply_caller4
-
-// Closure with indirect result but no captured indirect parameter.
-// CHECK-NOT: apply [[CALLER1]]
-// apply [[INLINEDCLOSURE_CALLER1]]()
-// CHECK-NOT: apply [[CALLER1]]
-
-// Closures with captured indirect parameters.
-// apply [[CALLER2]]([[CLOSURE2]])
-// apply [[CALLER3]]([[CLOSURE3]])
-// apply [[CALLER4]]([[CLOSURE4]])
-
-// CHECK: return
-sil @loop_driver : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> () {
-bb0(%0 : $Builtin.Int1, %1 : $Builtin.Int1):
-  %2 = function_ref @simple_partial_apply_fun : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
-  %3 = partial_apply %2(%0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
-  %4 = function_ref @simple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-  %5 = apply %4(%3) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-
-  %51 = function_ref @simple_partial_apply_2nd_level_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-  %52 = apply %51(%3) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-
-  %6 = partial_apply %2(%0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
-  %7 = function_ref @simple_partial_apply_caller_decl : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-  %8 = apply %7(%6) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-
-  %9 = alloc_stack $Builtin.Int1
-
-  %10 = function_ref @indirect_parameter_partial_apply_fun : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
-  %11 = partial_apply %10() : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
-  %12 = partial_apply %10(%9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
-  %13 = partial_apply %10(%1, %9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
-  %14 = partial_apply %10(%9, %1, %9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
-
-  %16 = function_ref @indirect_parameter_partial_apply_caller1 : $@convention(thin) (@callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1) -> ()
-  %17 = function_ref @indirect_parameter_partial_apply_caller2 : $@convention(thin) (@callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1) -> ()
-  %18 = function_ref @indirect_parameter_partial_apply_caller3 : $@convention(thin) (@callee_owned (@in Builtin.Int1) -> @out Builtin.Int1) -> ()
-  %19 = function_ref @indirect_parameter_partial_apply_caller4 : $@convention(thin) (@callee_owned () -> @out Builtin.Int1) -> ()
-  %20 = function_ref @indirect_parameter_partial_apply_caller5 : $@convention(thin) (@callee_owned () -> ()) -> ()
-
-  apply %16(%11) : $@convention(thin) (@callee_owned (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1) -> ()
-  apply %17(%12) : $@convention(thin) (@callee_owned (@in Builtin.Int1, Builtin.Int1) -> @out Builtin.Int1) -> ()
-  apply %18(%13) : $@convention(thin) (@callee_owned (@in Builtin.Int1) -> @out Builtin.Int1) -> ()
-  apply %19(%14) : $@convention(thin) (@callee_owned () -> @out Builtin.Int1) -> ()
-
-  // Make sure we handle when we already have an out parameter correctly.
-  %21 = alloc_stack $(Builtin.Int1, Builtin.Int1)
-  %22 = function_ref @indirect_parameter_partial_apply_caller6 : $@convention(thin) (@callee_owned () -> @out Builtin.Int1) -> @out Builtin.Int1
-  %23 = function_ref @indirect_parameter_partial_apply_caller7 : $@convention(thin) (@callee_owned () -> @out Builtin.Int1) -> @out (Builtin.Int1, Builtin.Int1)
-  %24 = partial_apply %10(%9, %1, %9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
-  %25 = partial_apply %10(%9, %1, %9) : $@convention(thin) (@in Builtin.Int1, Builtin.Int1, @in Builtin.Int1) -> @out Builtin.Int1
-  apply %22(%9, %24) : $@convention(thin) (@callee_owned () -> @out Builtin.Int1) -> @out Builtin.Int1
-  apply %23(%21, %25) : $@convention(thin) (@callee_owned () -> @out Builtin.Int1) -> @out (Builtin.Int1, Builtin.Int1)
-
-  dealloc_stack %21 : $*(Builtin.Int1, Builtin.Int1)
-  dealloc_stack %9 : $*Builtin.Int1
-
-  %26 = partial_apply %2(%0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
-  %27 = partial_apply %2(%0) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
-  %28 = function_ref @simple_multiple_partial_apply_caller : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1, @owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-  %29 = apply %28(%26, %27) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1, @owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-
-  %30 = function_ref @simple_partial_apply_fun2 : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
-  %31 = partial_apply %30(%1) : $@convention(thin) (Builtin.Int1, Builtin.Int1) -> Builtin.Int1
-  %32 = function_ref @simple_partial_apply_caller2 : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-  %33 = apply %32(%31) : $@convention(thin) (@owned @callee_owned (Builtin.Int1) -> Builtin.Int1) -> Builtin.Int1
-
-
-  %9999 = tuple()
-  return %9999 : $()
-}
\ No newline at end of file
diff --git a/test/SILOptimizer/funcsig_explode_heuristic.sil b/test/SILOptimizer/funcsig_explode_heuristic.sil
index 9a359a7ada031..a39819e6b78be 100644
--- a/test/SILOptimizer/funcsig_explode_heuristic.sil
+++ b/test/SILOptimizer/funcsig_explode_heuristic.sil
@@ -68,7 +68,7 @@ bb0(%0 : $LargeNonTrivialStructOneNonTrivialField):
 // We are using a single non-trivial field of the struct. We should explode this
 // so we eliminate the second non-trivial leaf.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @big_arg_with_one_nontrivial_use : $@convention(thin) (@guaranteed LargeNonTrivialStructOneNonTrivialField) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @big_arg_with_one_nontrivial_use : $@convention(thin) (@guaranteed LargeNonTrivialStructOneNonTrivialField) -> () {
 // CHECK: bb0([[ARG:%.*]] : $LargeNonTrivialStructOneNonTrivialField):
 // CHECK:   [[FUNC:%.*]] = function_ref @$s31big_arg_with_one_nontrivial_useTf4x_n
 // CHECK:   [[FIELD:%.*]] = struct_extract [[ARG]] : $LargeNonTrivialStructOneNonTrivialField, #LargeNonTrivialStructOneNonTrivialField.k1
@@ -86,7 +86,7 @@ bb0(%0 : $LargeNonTrivialStructOneNonTrivialField):
 // We are using a single non-trivial field and a single trivial field. We are
 // willing to blow this up.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @big_arg_with_one_nontrivial_use_one_trivial_use : $@convention(thin) (@guaranteed LargeNonTrivialStructOneNonTrivialField) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @big_arg_with_one_nontrivial_use_one_trivial_use : $@convention(thin) (@guaranteed LargeNonTrivialStructOneNonTrivialField) -> () {
 // CHECK: bb0([[ARG:%.*]] : $LargeNonTrivialStructOneNonTrivialField):
 // CHECK:   [[FUNC:%.*]] = function_ref @$s032big_arg_with_one_nontrivial_use_d9_trivial_F0Tf4x_n : $@convention(thin) (@guaranteed Klass, Builtin.Int32) -> ()
 // CHECK:   [[TRIVIAL_FIELD:%.*]] = struct_extract [[ARG]] : $LargeNonTrivialStructOneNonTrivialField, #LargeNonTrivialStructOneNonTrivialField.x1
@@ -107,7 +107,7 @@ bb0(%0 : $LargeNonTrivialStructOneNonTrivialField):
 
 // We can still explode this, since our limit is 3 values.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @big_arg_with_one_nontrivial_use_two_trivial_uses : $@convention(thin) (@guaranteed LargeNonTrivialStructOneNonTrivialField) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @big_arg_with_one_nontrivial_use_two_trivial_uses : $@convention(thin) (@guaranteed LargeNonTrivialStructOneNonTrivialField) -> () {
 // CHECK: bb0([[ARG:%.*]] : $LargeNonTrivialStructOneNonTrivialField):
 // CHECK:   [[FUNC:%.*]] = function_ref @$s48big_arg_with_one_nontrivial_use_two_trivial_usesTf4x_n : $@convention(thin)
 // CHECK:   [[TRIVIAL_FIELD1:%.*]] = struct_extract [[ARG]] : $LargeNonTrivialStructOneNonTrivialField, #LargeNonTrivialStructOneNonTrivialField.x2
@@ -168,7 +168,7 @@ bb0(%0 : $LargeNonTrivialStructOneNonTrivialField):
 // We are using a single non-trivial field of the struct. We should explode this
 // so we eliminate the second non-trivial leaf.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @big_arg_with_one_nontrivial_use_o2g_other_dead : $@convention(thin) (@owned LargeNonTrivialStructOneNonTrivialField) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @big_arg_with_one_nontrivial_use_o2g_other_dead : $@convention(thin) (@owned LargeNonTrivialStructOneNonTrivialField) -> () {
 // CHECK-NOT: release_value
 // CHECK: apply
 // CHECK-NOT: release_value
@@ -190,7 +190,7 @@ bb0(%0 : $LargeNonTrivialStructOneNonTrivialField):
 //
 // We check that we can inline this correctly in the inline test.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @big_arg_with_one_nontrivial_use_o2g : $@convention(thin) (@owned LargeNonTrivialStructOneNonTrivialField) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @big_arg_with_one_nontrivial_use_o2g : $@convention(thin) (@owned LargeNonTrivialStructOneNonTrivialField) -> () {
 // CHECK: bb0([[ARG:%.*]] : $LargeNonTrivialStructOneNonTrivialField):
 // CHECK:   [[FUNC:%.*]] = function_ref @$s35big_arg_with_one_nontrivial_use_o2gTf4x_n : $@convention(thin) (@owned Klass, @owned Klass) -> ()
 // CHECK:   apply [[FUNC]](
diff --git a/test/SILOptimizer/funcsig_opaque.sil b/test/SILOptimizer/funcsig_opaque.sil
index 05ba32a1de053..52e904dd08311 100644
--- a/test/SILOptimizer/funcsig_opaque.sil
+++ b/test/SILOptimizer/funcsig_opaque.sil
@@ -14,7 +14,7 @@ sil @testAggregateArgHelper : $@convention(thin) (@owned R<S>) -> ()
 
 // Test owned-to-guaranteed transformation of opaque arguments.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @testAggregateArg : $@convention(thin) (@in R<S>) -> @out () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @testAggregateArg : $@convention(thin) (@in R<S>) -> @out () {
 // CHECK: bb0(%0 : $R<S>):
 // CHECK:   [[F:%.*]] = function_ref @$s16testAggregateArgTf4g_n : $@convention(thin) (@in_guaranteed R<S>) -> @out ()
 // CHECK:   [[CALL:%.*]] = apply [[F]](%0) : $@convention(thin) (@in_guaranteed R<S>) -> @out ()
diff --git a/test/SILOptimizer/funcsig_pseudogenerics.sil b/test/SILOptimizer/funcsig_pseudogenerics.sil
index 25ab67676d6ba..6456057d95eaa 100644
--- a/test/SILOptimizer/funcsig_pseudogenerics.sil
+++ b/test/SILOptimizer/funcsig_pseudogenerics.sil
@@ -12,7 +12,7 @@ import Swift
 import Foundation
 import objc_generics
 
-// CHECK: sil [signature_optimized_thunk] [always_inline] @non_pseudo_method :
+// CHECK: sil [signature_optimized_thunk] [heuristic_always_inline] @non_pseudo_method :
 sil @non_pseudo_method : $@convention(thin) <T: AnyObject> (Int64) -> () {
 entry(%0 : $Int64):
   return undef : $()
diff --git a/test/SILOptimizer/function_uses.sil b/test/SILOptimizer/function_uses.sil
index 2885e7855cde9..b9027393e2a35 100644
--- a/test/SILOptimizer/function_uses.sil
+++ b/test/SILOptimizer/function_uses.sil
@@ -180,13 +180,13 @@ struct SP2 : P {
 // CHECK-NEXT:  <unknown uses>
 // CHECK-NEXT:  ]
 // CHECK-NEXT:  End function witness
-sil @witness : $@convention(witness_method: P) (@inout SP) -> () {
+sil @witness : $@convention(witness_method: P) (@in_guaranteed SP) -> () {
 bb0(%0 : $*SP):
   %7 = tuple ()
   return %7 : $()
 }
 
-sil @witness2 : $@convention(witness_method: P) (@inout SP) -> () {
+sil @witness2 : $@convention(witness_method: P) (@in_guaranteed SP) -> () {
 bb0(%0 : $*SP):
   %7 = tuple ()
   return %7 : $()
diff --git a/test/SILOptimizer/functionsigopts.sil b/test/SILOptimizer/functionsigopts.sil
index c6035a6a08262..b7b8c6ac90999 100644
--- a/test/SILOptimizer/functionsigopts.sil
+++ b/test/SILOptimizer/functionsigopts.sil
@@ -1,5 +1,8 @@
-// RUN: %target-sil-opt -sil-print-types -sil-inline-generics -enable-sil-verify-all -inline -function-signature-opts %s | %FileCheck %s
-// RUN: %target-sil-opt -sil-print-types -sil-inline-generics -enable-sil-verify-all -inline -function-signature-opts %s | %FileCheck -check-prefix=CHECK-NEGATIVE %s
+// RUN: %target-sil-opt -sil-print-types -sil-inline-generics -enable-sil-verify-all -inline -function-signature-opts -enable-experimental-feature Lifetimes %s | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -sil-inline-generics -enable-sil-verify-all -inline -function-signature-opts -enable-experimental-feature Lifetimes %s | %FileCheck -check-prefix=CHECK-NEGATIVE %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
 
 import Builtin
 import Swift
@@ -86,7 +89,7 @@ bb0:
   return %4 : $()
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @argument_with_incomplete_epilogue_release
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @argument_with_incomplete_epilogue_release
 // CHECK: [[IN2:%.*]] = struct_extract [[IN1:%.*]] : $goo, #goo.top
 // CHECK: function_ref @$s41argument_with_incomplete_epilogue_releaseTf4x_nTf4gn_n : $@convention(thin) (@guaranteed foo, @owned foo) -> ()
 // CHECK: release_value [[IN2]]
@@ -146,7 +149,7 @@ sil [serialized] @create_object : $@convention(thin) () -> Builtin.NativeObject
 // Make sure argument is exploded and the baz part is not passed in as argument, as its only use
 // is a release.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @dead_argument_due_to_only_release_user
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @dead_argument_due_to_only_release_user
 // CHECK: [[IN:%.*]] = function_ref @$s38dead_argument_due_to_only_release_userTf4gX_n
 // CHECK: [[IN2:%.*]] = struct_extract [[IN1:%.*]] : $boo, #boo.a
 // CHECK: apply [[IN]]([[IN2]])
@@ -185,7 +188,7 @@ bb0(%0 : $boo):
 
 // Make sure argument is exploded and the baz part is not passed in as argument, as its only use
 // is a release.
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @dead_argument_due_to_only_release_user_but__exploded
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @dead_argument_due_to_only_release_user_but__exploded
 // CHECK: [[FN1:%.*]] = function_ref @$s52dead_argument_due_to_only_release_user_but__explodedTf4gX_n
 // CHECK: [[IN1:%.*]] = struct_extract %0 : $lotsoffield, #lotsoffield.c
 // CHECK: [[IN2:%.*]] = struct_extract %0 : $lotsoffield, #lotsoffield.b
@@ -231,7 +234,7 @@ bb0(%0 : $lotsoffield):
 // point from an ARC perspective in splitting it up. We still want to perform
 // owned to guaranteed though.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @dead_argument_due_to_more_than_release_user
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @dead_argument_due_to_more_than_release_user
 // CHECK: bb{{[0-9]+}}([[BOO:%.*]] : $boo):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s43dead_argument_due_to_more_than_release_userTf4g_n : $@convention(thin) (@guaranteed boo) -> (Int, Int)
 // CHECK: [[RESULT:%.*]] = apply [[FUNCTION]]([[BOO]])
@@ -317,7 +320,7 @@ bb3:
 
 // Make sure %0 is a dead argument.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @exploded_release_to_dead_argument
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @exploded_release_to_dead_argument
 // CHECK: bb0([[INPUT_ARG0:%[0-9]+]] : $boo):
 // CHECK: [[IN1:%.*]] = function_ref @$s33exploded_release_to_dead_argumentTf4d_n
 // CHECK: apply [[IN1]]()
@@ -362,7 +365,7 @@ bb0(%0 : $boo):
 
 // Make sure %0 is not a dead argument, but gets converted to a guaranteed arg.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @exploded_release_to_guaranteed_param
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @exploded_release_to_guaranteed_param
 // CHECK: bb0([[INPUT_ARG0:%[0-9]+]] : $boo):
 // CHECK: [[IN1:%.*]] = function_ref @$s36exploded_release_to_guaranteed_paramTf4gX_n
 // CHECK: release_value [[INPUT_ARG0]]
@@ -404,7 +407,7 @@ bb0(%0 : $boo):
   return %6 : $()
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @single_owned_return_value
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @single_owned_return_value
 // CHECK: bb0([[INPUT_ARG0:%[0-9]+]] : $boo):
 // CHECK: [[IN1:%.*]] = function_ref @$s25single_owned_return_valueTf4n_g
 // CHECK: [[IN2:%.*]] = apply [[IN1]]([[INPUT_ARG0]]
@@ -440,7 +443,7 @@ bb0(%0 : $boo):
 }
 
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @single_owned_return_value_with_self_recursion
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @single_owned_return_value_with_self_recursion
 // CHECK: function_ref @$s45single_owned_return_value_with_self_recursionTf4n_g
 // CHECK: [[RET:%.*]] = apply
 // CHECK: retain_value [[RET]]
@@ -556,7 +559,7 @@ bb3(%35 : $IndirectEnum):
 
 // Make sure we do not move the retain_value in the throw block.
 //
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @owned_to_unowned_retval_with_error_result : $@convention(thin) (@owned boo) -> (@owned boo, @error any Error) {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @owned_to_unowned_retval_with_error_result : $@convention(thin) (@owned boo) -> (@owned boo, @error any Error) {
 // CHECK: function_ref @$s41owned_to_unowned_retval_with_error_resultTfq4n_g : $@convention(thin) (@owned boo) -> (boo, @error any Error)
 // CHECK: bb1
 // CHECK-NOT: retain_value
@@ -598,7 +601,7 @@ bb2:
   throw undef : $Error
 }
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @dead_arg_with_callsites : $@convention(thin) (Builtin.NativeObject, Builtin.NativeObject) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @dead_arg_with_callsites : $@convention(thin) (Builtin.NativeObject, Builtin.NativeObject) -> () {
 // CHECK: bb0
 // CHECK-NEXT: function_ref
 // CHECK-NEXT: function_ref @$s23dead_arg_with_callsitesTfq4dn_n : $@convention(thin) (Builtin.NativeObject) -> ()
@@ -866,7 +869,7 @@ bb0(%0 : $goo):
 //========================================
 // @owned => @guaranteed with error result
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @owned_to_guaranteed_with_error_result : $@convention(thin) (@owned Builtin.NativeObject, Int) -> (Int, @error any Error) {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @owned_to_guaranteed_with_error_result : $@convention(thin) (@owned Builtin.NativeObject, Int) -> (Int, @error any Error) {
 // CHECK: [[FUNC_REF:%[0-9]+]] = function_ref @$s37owned_to_guaranteed_with_error_resultTfq4gn_n : $@convention(thin) (@guaranteed Builtin.NativeObject, Int)
 // CHECK: try_apply [[FUNC_REF]]({{.*}}, normal bb1, error bb2
 // CHECK: bb1([[NORMRET:%[0-9]+]] : $Int):
@@ -993,7 +996,7 @@ bb2(%7 : $Error):
 // @owned => @guaranteed
 
 // We should optimize this call.
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @owned_to_guaranteed_simple_singlebb_callee : $@convention(thin) (@owned Builtin.NativeObject) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @owned_to_guaranteed_simple_singlebb_callee : $@convention(thin) (@owned Builtin.NativeObject) -> () {
 // CHECK: [[FUNC_REF:%[0-9]+]] = function_ref @$s42owned_to_guaranteed_simple_singlebb_calleeTfq4g_n : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
 // CHECK: apply [[FUNC_REF]]
 // CHECK-NOT: fix_lifetime
@@ -1142,7 +1145,7 @@ bb0(%0 : $Builtin.NativeObject):
 // We should be able to optimize this callee since the release is in the exit
 // BB. Additionally this test makes sure that we delete dead parameters before
 // invalidating the owned argument -> release map.
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @owned_to_guaranteed_multibb_callee_with_release_in_exit : $@convention(thin) (Builtin.Int1, @owned Builtin.NativeObject) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @owned_to_guaranteed_multibb_callee_with_release_in_exit : $@convention(thin) (Builtin.Int1, @owned Builtin.NativeObject) -> () {
 // CHECK-NOT: fix_lifetime
 // CHECK: release_value %1 : $Builtin.NativeObject
 sil [serialized] @owned_to_guaranteed_multibb_callee_with_release_in_exit : $@convention(thin) (Builtin.Int1, @owned Builtin.NativeObject) -> () {
@@ -1225,7 +1228,7 @@ bb2:
   return %1 : $()
 }
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @owned_to_guaranteed_simple_singlebb_multiple_arg_callee : $@convention(thin) (Builtin.Int1, @owned Builtin.NativeObject, Builtin.Int1) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @owned_to_guaranteed_simple_singlebb_multiple_arg_callee : $@convention(thin) (Builtin.Int1, @owned Builtin.NativeObject, Builtin.Int1) -> () {
 sil [serialized] @owned_to_guaranteed_simple_singlebb_multiple_arg_callee : $@convention(thin) (Builtin.Int1, @owned Builtin.NativeObject, Builtin.Int1) -> () {
 bb0(%0 : $Builtin.Int1, %1 : $Builtin.NativeObject, %2 : $Builtin.Int1):
   // make it a non-trivial function
@@ -1276,7 +1279,7 @@ bb3:
   return %3 : $()
 }
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @owned_to_guaranteed_multibb_callee_with_release_in_exit_two_args_1 : $@convention(thin) (@owned Builtin.NativeObject, @owned Builtin.NativeObject) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @owned_to_guaranteed_multibb_callee_with_release_in_exit_two_args_1 : $@convention(thin) (@owned Builtin.NativeObject, @owned Builtin.NativeObject) -> () {
 // CHECK: bb0([[INPUT_PTR1:%.*]] : $Builtin.NativeObject, [[INPUT_PTR2:%.*]] : $Builtin.NativeObject):
 // CHECK: release_value [[INPUT_PTR2]] : $Builtin.NativeObject
 // CHECK: release_value [[INPUT_PTR1]] : $Builtin.NativeObject
@@ -1321,7 +1324,7 @@ bb2:
   return %2 : $()
 }
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @owned_to_guaranteed_multibb_callee_with_release_in_exit_two_args_2 : $@convention(thin) (@owned Builtin.NativeObject, @owned Builtin.NativeObject) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @owned_to_guaranteed_multibb_callee_with_release_in_exit_two_args_2 : $@convention(thin) (@owned Builtin.NativeObject, @owned Builtin.NativeObject) -> () {
 // CHECK: bb0([[INPUT_PTR1:%.*]] : $Builtin.NativeObject, [[INPUT_PTR2:%.*]] : $Builtin.NativeObject):
 // CHECK: release_value [[INPUT_PTR2]] : $Builtin.NativeObject
 // CHECK: release_value [[INPUT_PTR1]] : $Builtin.NativeObject
@@ -1471,7 +1474,7 @@ bb0(%0 : $foo):
 
 // We should remove the array semantic from specialized calls.
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] [_semantics "array.foobar"] @array_semantic : $@convention(method) (@owned Builtin.NativeObject) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] [_semantics "array.foobar"] @array_semantic : $@convention(method) (@owned Builtin.NativeObject) -> () {
 // CHECK: [[FUNC_REF:%[0-9]+]] = function_ref @$s14array_semanticTfq4g_n : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
 // CHECK: apply [[FUNC_REF]]
 // CHECK: release_value
@@ -1537,7 +1540,7 @@ bb0(%0 : $Builtin.Int32):
   return %9999 : $()
 }
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @s2 : $@convention(thin) (Builtin.Int32) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @s2 : $@convention(thin) (Builtin.Int32) -> () {
 sil [serialized] @s2 : $@convention(thin) (Builtin.Int32) -> () {
 bb0(%0 : $Builtin.Int32):
   // make it a non-trivial function
@@ -1574,7 +1577,7 @@ bb0(%0 : $Builtin.Int32):
   return %9999 : $()
 }
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @s1 : $@convention(thin) (Builtin.Int32) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @s1 : $@convention(thin) (Builtin.Int32) -> () {
 sil [serialized] @s1 : $@convention(thin) (Builtin.Int32) -> () {
 bb0(%0 : $Builtin.Int32):
   // make it a non-trivial function
@@ -1605,13 +1608,13 @@ bb0(%0 : $Builtin.Int32):
   return %9999 : $()
 }
 
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @generic_owned_to_guaranteed : $@convention(thin) <T where T : KlassFoo> (@owned T) -> Int64
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @generic_owned_to_guaranteed : $@convention(thin) <T where T : KlassFoo> (@owned T) -> Int64
 // CHECK: function_ref @$s27generic_owned_to_guaranteedTf4g_n 
 // CHECK: apply
 // CHECK: release_value
 // CHECK: end sil function 'generic_owned_to_guaranteed'
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @generic_owned_to_guaranteed_caller : $@convention(thin) <T where T : KlassFoo> (@owned T) -> Int64
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @generic_owned_to_guaranteed_caller : $@convention(thin) <T where T : KlassFoo> (@owned T) -> Int64
 // CHECK: function_ref @$s34generic_owned_to_guaranteed_callerTf4g_n 
 // CHECK: apply
 // CHECK: release_value
@@ -1645,13 +1648,13 @@ bb0(%0 : $T):
   return %15 : $Int64
 }
 
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @generic_in_to_guaranteed : $@convention(thin) <T where T : P> (@in T) -> Int64
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @generic_in_to_guaranteed : $@convention(thin) <T where T : P> (@in T) -> Int64
 // CHECK: function_ref @$s24generic_in_to_guaranteedTf4g_n 
 // CHECK: apply
 // CHECK: destroy_addr
 // CHECK: end sil function 'generic_in_to_guaranteed'
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @generic_in_to_guaranteed_caller : $@convention(thin) <T where T : P> (@in T) -> Int64
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @generic_in_to_guaranteed_caller : $@convention(thin) <T where T : P> (@in T) -> Int64
 // CHECK: function_ref @$s31generic_in_to_guaranteed_callerTf4g_n 
 // CHECK: apply
 // CHECK: destroy_addr
@@ -1684,7 +1687,7 @@ bb0(%0 : $*T):
   return %15 : $Int64
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @generic_func_with_dead_non_generic_arg : $@convention(thin) <T> (@owned foo, @in T) -> ()
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @generic_func_with_dead_non_generic_arg : $@convention(thin) <T> (@owned foo, @in T) -> ()
 // CHECK: function_ref @$s027generic_func_with_dead_non_A4_argTf4dd_n : $@convention(thin) () -> ()
 // Call the specialization which is not polymorphic.
 // CHECK: apply
@@ -1697,7 +1700,7 @@ bb0(%0 : $foo, %1 : $*T):
   return %r : $()
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @generic_func_with_dead_generic_arg : $@convention(thin) <T> (Int64, @in T) -> Int64
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @generic_func_with_dead_generic_arg : $@convention(thin) <T> (Int64, @in T) -> Int64
 // CHECK: function_ref @$s023generic_func_with_dead_A4_argTf4nd_n : $@convention(thin) (Int64) -> Int64 
 // Call the specialization which is not polymorphic.
 // CHECK: apply
@@ -1709,7 +1712,7 @@ bb0(%0 : $Int64, %1 : $*T):
   return %0 : $Int64
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @generic_func_with_unused_generic_param_and_non_generic_arg : $@convention(thin) <T> (Int64) -> Int64
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @generic_func_with_unused_generic_param_and_non_generic_arg : $@convention(thin) <T> (Int64) -> Int64
 // CHECK: function_ref @$s025generic_func_with_unused_a15_param_and_non_A4_argTf4n_n : $@convention(thin) (Int64) -> Int64 
 // Call the specialization which is not polymorphic.
 // CHECK: apply
@@ -1726,7 +1729,7 @@ bb0(%0 : $Int64):
   return %r : $Int64
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @generic_func_with_unused_generic_param_and_dead_non_generic_arg : $@convention(thin) <T> (Int64, Int64) -> Int64
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @generic_func_with_unused_generic_param_and_dead_non_generic_arg : $@convention(thin) <T> (Int64, Int64) -> Int64
 // CHECK: function_ref @$s025generic_func_with_unused_a20_param_and_dead_non_A4_argTf4nd_n : $@convention(thin) (Int64) -> Int64 
 // Call the specialization which is not polymorphic.
 // CHECK: apply
@@ -1743,7 +1746,7 @@ bb0(%0 : $Int64):
   return %r : $Int64
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @generic_func_with_unused_generic_param_and_dead_generic_arg : $@convention(thin) <T> (@in_guaranteed T) -> ()
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @generic_func_with_unused_generic_param_and_dead_generic_arg : $@convention(thin) <T> (@in_guaranteed T) -> ()
 // CHECK: function_ref @$s025generic_func_with_unused_a16_param_and_dead_A4_argTf4d_n : $@convention(thin) () -> ()
 // Call the specialization which is not polymorphic.
 // CHECK: apply
@@ -1762,7 +1765,7 @@ bb0(%0 : $*T):
   return %r : $()
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @generic_func_with_unused_generic_param_and_dead_owned_generic_arg : $@convention(thin) <T where T : KlassFoo> (@owned T) -> ()
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @generic_func_with_unused_generic_param_and_dead_owned_generic_arg : $@convention(thin) <T where T : KlassFoo> (@owned T) -> ()
 // CHECK: function_ref @$s025generic_func_with_unused_a22_param_and_dead_owned_A4_argTf4d_n : $@convention(thin) () -> ()
 // Call the specialization which is not polymorphic.
 // CHECK: apply
@@ -1783,7 +1786,7 @@ bb0(%0 : $T):
   return %r : $()
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @generic_func_with_multple_generic_args_and_dead_generic_arg : $@convention(thin) <T, S> (@in T, @in S) -> ()
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @generic_func_with_multple_generic_args_and_dead_generic_arg : $@convention(thin) <T, S> (@in T, @in S) -> ()
 // CHECK: function_ref @$s026generic_func_with_multple_a15_args_and_dead_A4_argTf4nd_n : $@convention(thin) <τ_0_0, τ_0_1> (@in τ_0_0) -> ()
 // Call the specialization which has only one function argument, because another one is dead
 // and was eliminated.
@@ -1811,7 +1814,7 @@ bb0(%0 : $*T):
   return %r : $()
 }
 
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @value_generic_count : $@convention(thin) <let N : Int> (ValueGenericType<N>) -> Int
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @value_generic_count : $@convention(thin) <let N : Int> (ValueGenericType<N>) -> Int
 // CHECK:         function_ref @$s19value_generic_countTf4d_n : $@convention(thin) <let τ_0_0 : Int> () -> Int
 // CHECK:         apply
 // CHECK: } // end sil function 'value_generic_count'
@@ -1832,6 +1835,28 @@ bb0(%0 : $ValueGenericType<N>):
   return %2 : $Int
 }
 
+struct NE<T> : ~Escapable where T : ~Escapable {
+  @_lifetime(copy t)
+  init(_ t: borrowing T)
+}
+
+// CHECK-NOT: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @neinit :
+sil [noinline] @neinit : $@convention(method) <T where T : ~Escapable> (@in_guaranteed T, @thin NE<T>.Type) -> @lifetime(copy 0) @owned NE<T> {
+bb0(%0 : @noImplicitCopy $*T, %1 : $@thin NE<T>.Type):
+  debug_value [moveable_value_debuginfo] %0, let, name "t", argno 1, expr op_deref
+  %3 = struct $NE<T> ()
+  return %3
+}
+
+sil hidden @neinit_caller : $@convention(thin) <T where T : ~Escapable> (@in_guaranteed T) -> @lifetime(copy 0) @owned NE<T> {
+bb0(%0 : @noImplicitCopy $*T):
+  debug_value [moveable_value_debuginfo] %0, let, name "t", argno 1, expr op_deref
+  %2 = metatype $@thin NE<T>.Type
+  %3 = function_ref @neinit : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed τ_0_0, @thin NE<τ_0_0>.Type) -> @lifetime(copy 0) @owned NE<τ_0_0>
+  %4 = apply %3<T>(%0, %2) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed τ_0_0, @thin NE<τ_0_0>.Type) -> @lifetime(copy 0) @owned NE<τ_0_0>
+  return %4
+}
+
 // CHECK-LABEL: sil shared @$s36exploded_release_to_guaranteed_paramTf4gX_n
 // CHECK: bb0([[INPUT_ARG0:%[0-9]+]] : $Int):
 // CHECK-NOT: strong_release
diff --git a/test/SILOptimizer/functionsigopts_crash.swift b/test/SILOptimizer/functionsigopts_crash.swift
index 60f87eb25f358..d8d987d519bf3 100644
--- a/test/SILOptimizer/functionsigopts_crash.swift
+++ b/test/SILOptimizer/functionsigopts_crash.swift
@@ -1,4 +1,7 @@
-// RUN: %target-swift-frontend -module-name main -O -emit-sil -primary-file %s | %FileCheck %s
+// RUN: %target-swift-frontend -module-name main -O -emit-sil -primary-file %s -enable-experimental-feature Lifetimes | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
 
 protocol P {
   func foo()
@@ -35,3 +38,32 @@ func testit(_ p: P) {
 public func callit(s: S) {
   testit(s)
 }
+
+// Check that FSO does not trigger a verifier error caused by a mutated @in argument which is 
+// converted to an @in_guaranteed argument (which must not be mutated).
+
+public protocol IP<Element> {
+  associatedtype Element
+
+  init<Iterator>(iterator: consuming Iterator) where Iterator: IteratorProtocol, Iterator.Element == Element
+}
+
+extension Array: IP {
+  public init<Iterator>(iterator: consuming Iterator) where Iterator: IteratorProtocol, Iterator.Element == Element {
+    self.init()
+    while let next = iterator.next() {
+      append(next)
+    }
+  }
+}
+
+struct NE<T : ~Escapable> : ~Escapable {
+  @_lifetime(copy t)
+  init(_ t: borrowing T) {}
+}
+
+@_lifetime(copy t)
+func getNE<T : ~Escapable>(_ t: borrowing T) -> NE<T> {
+  return NE(t)
+}
+
diff --git a/test/SILOptimizer/functionsigopts_sroa.sil b/test/SILOptimizer/functionsigopts_sroa.sil
index 06a84ed664b6c..e3cbf3fc44292 100644
--- a/test/SILOptimizer/functionsigopts_sroa.sil
+++ b/test/SILOptimizer/functionsigopts_sroa.sil
@@ -472,7 +472,7 @@ bb0(%0 : $S2):
 
 /// Verify that an aggregate argument containing a single non-trivial live leaf
 /// is not exploded.
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @owned_struct_1_callee : $@convention(thin) (@owned S5, @owned S5) -> (Builtin.Int16, Builtin.Int32, Builtin.Int16, Builtin.Int32) {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @owned_struct_1_callee : $@convention(thin) (@owned S5, @owned S5) -> (Builtin.Int16, Builtin.Int32, Builtin.Int16, Builtin.Int32) {
 // CHECK: bb0({{%.*}} : $S5, [[INPUT:%.*]] : $S5):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s21owned_struct_1_calleeTfq4dg_n : $@convention(thin) (@guaranteed S5) -> (Builtin.Int16, Builtin.Int32, Builtin.Int16, Builtin.Int32)
 // CHECK: [[RESULT:%.*]] = apply [[FUNCTION]]([[INPUT]])
@@ -536,7 +536,7 @@ bb0(%0 : $S5):
 
 /// Verify that argument explosion that increases argument count before and
 /// after dead argument elimination behaves properly.
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @owned_struct_2_callee : $@convention(thin) (Builtin.Int256, Builtin.Int256, @owned S4Triple, Builtin.Int128, Builtin.Int128) -> (Builtin.Int256, Builtin.Int256, Builtin.Int128, Builtin.Int128) {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @owned_struct_2_callee : $@convention(thin) (Builtin.Int256, Builtin.Int256, @owned S4Triple, Builtin.Int128, Builtin.Int128) -> (Builtin.Int256, Builtin.Int256, Builtin.Int128, Builtin.Int128) {
 // CHECK: bb0([[IN1:%.*]] : $Builtin.Int256, [[IN2:%.*]] : $Builtin.Int256, [[TRIPLE:%.*]] : $S4Triple, [[IN4:%.*]] : $Builtin.Int128, [[IN5:%.*]] : $Builtin.Int128):
 // CHECK: [[FN:%.*]] = function_ref @$s21owned_struct_2_calleeTfq4ndgXdn_n : $@convention(thin) (Builtin.Int256, @guaranteed S4, @guaranteed S4, Builtin.Int128) -> (Builtin.Int256, Builtin.Int256, Builtin.Int128, Builtin.Int128)
 // CHECK: [[TRIPLEF3:%.*]] = struct_extract [[TRIPLE]] : $S4Triple, #S4Triple.f3
@@ -597,7 +597,7 @@ bb0(%0 : $Builtin.Int256, %1 : $S4Triple, %2 : $Builtin.Int128):
 }
 
 /// Verify that pointer arguments are ignored for now.
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @ignore_ptrs_callee : $@convention(thin) (@in S4Pair, S4Pair, S4Pair) -> (S4, S4) {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @ignore_ptrs_callee : $@convention(thin) (@in S4Pair, S4Pair, S4Pair) -> (S4, S4) {
 // CHECK: bb0([[POINTER:%.*]] : $*S4Pair, [[PAIR1:%.*]] : $S4Pair, [[PAIR2:%.*]] : $S4Pair):
 // CHECK: [[FN:%.*]] = function_ref @$s18ignore_ptrs_calleeTfq4nxx_n : $@convention(thin) (@in S4Pair, S4, S4) -> (S4, S4)
 // CHECK: [[VALUE1:%.*]] = struct_extract [[PAIR1]] : $S4Pair, #S4Pair.f1
@@ -712,7 +712,7 @@ bb0(%0 : $FakeStaticString, %1 : $FakeString, %2 : $FakeStaticString):
 /// Verify that in the face of an exploded argument the ordering of arguments is
 /// based on ordering of fields in the original argument rather than ordering of
 /// usage in the function being specialized.
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @check_out_of_order_uses_callee : $@convention(thin) (S4Triple) -> () {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @check_out_of_order_uses_callee : $@convention(thin) (S4Triple) -> () {
 // CHECK: bb0([[TRIPLE:%.*]] : $S4Triple):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s30check_out_of_order_uses_calleeTfq4x_n : $@convention(thin) (S4, S4) -> ()
 // CHECK: [[INPUT1F2:%.*]] = struct_extract [[TRIPLE]] : $S4Triple, #S4Triple.f2
@@ -770,7 +770,7 @@ bb0(%0 : $S4Triple):
 }
 
 // Make sure that we do not SROA classes.
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @class_callee_1 : $@convention(thin) (@owned C1, Builtin.Int32) -> Builtin.Int32 {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @class_callee_1 : $@convention(thin) (@owned C1, Builtin.Int32) -> Builtin.Int32 {
 // CHECK: bb0([[IN1:%.*]] : $C1, [[IN2:%.*]] : $Builtin.Int32):
 // CHECK: [[FN:%.*]] = function_ref @$s14class_callee_1Tfq4gn_n : $@convention(thin) (@guaranteed C1, Builtin.Int32) -> Builtin.Int32
 // CHECK: apply [[FN]]([[IN1]], [[IN2]]) : $@convention(thin) (@guaranteed C1, Builtin.Int32) -> Builtin.Int32
@@ -809,7 +809,7 @@ bb0(%0 : $C1, %1 : $Builtin.Int32):
   return %1 : $Builtin.Int32
 }
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @class_caller_1 : $@convention(thin) (@owned C1, Builtin.Int32) -> Builtin.Int32 {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @class_caller_1 : $@convention(thin) (@owned C1, Builtin.Int32) -> Builtin.Int32 {
 // CHECK: bb0([[IN1:%.*]] : $C1, [[IN2:%.*]] : $Builtin.Int32):
 // CHECK: [[FN:%.*]] = function_ref @$s14class_callee_1Tfq4gn_n : $@convention(thin) (@guaranteed C1, Builtin.Int32) -> Builtin.Int32
 // CHECK: apply [[FN]]([[IN1]], [[IN2]]) : $@convention(thin) (@guaranteed C1, Builtin.Int32) -> Builtin.Int32
@@ -892,7 +892,7 @@ only(%tet : $S4Fourtytet):
   return %result : $S4
 }
 
-// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [always_inline] @more_than_32_type_sized_callee : $@convention(thin) (S4Fourtytet) -> S4 {
+// CHECK-LABEL: sil [serialized] [signature_optimized_thunk] [heuristic_always_inline] @more_than_32_type_sized_callee : $@convention(thin) (S4Fourtytet) -> S4 {
 // CHECK-LABEL: } // end sil function 'more_than_32_type_sized_callee'
 sil [serialized] @more_than_32_type_sized_callee : $@convention(thin) (S4Fourtytet) -> S4 {
 bb0(%tet : $S4Fourtytet):
diff --git a/test/SILOptimizer/functionsigopts_trivial.sil b/test/SILOptimizer/functionsigopts_trivial.sil
index 9cc91b5d89392..8aac9058ba52f 100644
--- a/test/SILOptimizer/functionsigopts_trivial.sil
+++ b/test/SILOptimizer/functionsigopts_trivial.sil
@@ -158,7 +158,7 @@ only(%wrapper : $Wrapper):
 // potentially trivial because specializing the function will not result in a
 // thunk.
 //
-// CHECK-LABEL: sil shared [signature_optimized_thunk] [always_inline] @take_wrapper_shared : $@convention(thin) (Wrapper) -> () {
+// CHECK-LABEL: sil shared [signature_optimized_thunk] [heuristic_always_inline] @take_wrapper_shared : $@convention(thin) (Wrapper) -> () {
 // CHECK: bb{{[0-9]*}}([[WRAPPER:%.*]] : $Wrapper)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s19take_wrapper_sharedTf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[WRAPPER]] : $Wrapper, #Wrapper.klass
@@ -236,7 +236,7 @@ only(%wrapper : $Wrapper):
 // dead leaves of the relevant sort, that being potentially trivial because
 // specializing the function will not result in a thunk.
 //
-// CHECK-LABEL: sil private [signature_optimized_thunk] [always_inline] @take_wrapper_private : $@convention(thin) (Wrapper) -> () {
+// CHECK-LABEL: sil private [signature_optimized_thunk] [heuristic_always_inline] @take_wrapper_private : $@convention(thin) (Wrapper) -> () {
 // CHECK: bb{{[0-9]*}}([[WRAPPER:%.*]] : $Wrapper)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s20take_wrapper_privateTf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[WRAPPER]] : $Wrapper, #Wrapper.klass
@@ -282,7 +282,7 @@ only(%wrapper : $Wrapper):
 // changes there would be needless ARC traffic around the klass field.  So, 
 // argument explosion *should* result in a specialization in this case.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @take_wrapper_for_int : $@convention(thin) (Wrapper) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @take_wrapper_for_int : $@convention(thin) (Wrapper) -> () {
 // CHECK: bb{{[0-9]*}}([[WRAPPER:%.*]] : $Wrapper)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s20take_wrapper_for_intTf4x_n
 // CHECK: [[INT:%.*]] = struct_extract [[WRAPPER]] : $Wrapper, #Wrapper.int
@@ -320,7 +320,7 @@ only(%wrapper : $Wrapper):
 // changes there would be needless ARC traffic around the klass field.  So, 
 // argument explosion *should* result in a specialization in this case.
 //
-// CHECK-LABEL: sil public_external [signature_optimized_thunk] [always_inline] @take_wrapper_for_int_public_external : $@convention(thin) (Wrapper) -> () {
+// CHECK-LABEL: sil public_external [signature_optimized_thunk] [heuristic_always_inline] @take_wrapper_for_int_public_external : $@convention(thin) (Wrapper) -> () {
 // CHECK: bb{{[0-9]*}}([[WRAPPER:%.*]] : $Wrapper)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s36take_wrapper_for_int_public_externalTf4x_n
 // CHECK: [[INT:%.*]] = struct_extract [[WRAPPER]] : $Wrapper, #Wrapper.int
@@ -357,7 +357,7 @@ only(%wrapper : $Wrapper):
 // Wrapper from which it only uses the int field.  The klass field goes unused.
 // Without changes there would be needless ARC traffic around the klass field.
 // So, argument explosion *should* result in a specialization in this case.
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @take_wrapper_for_int_hidden
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @take_wrapper_for_int_hidden
 // CHECK: bb{{[0-9]*}}([[WRAPPER:%.*]] : $Wrapper)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s27take_wrapper_for_int_hiddenTf4x_n : $@convention(thin) (Int) -> ()
 // CHECK: [[INT:%.*]] = struct_extract [[WRAPPER]] : $Wrapper, #Wrapper.int
@@ -394,7 +394,7 @@ only(%wrapper : $Wrapper):
 // Wrapper from which it only uses the int field.  The klass field goes unused.
 // Without changes there would be needless ARC traffic around the klass field.
 // So, argument explosion *should* result in a specialization in this case.
-// CHECK-LABEL: sil private [signature_optimized_thunk] [always_inline] @take_wrapper_for_int_private
+// CHECK-LABEL: sil private [signature_optimized_thunk] [heuristic_always_inline] @take_wrapper_for_int_private
 // CHECK: bb{{[0-9]*}}([[WRAPPER:%.*]] : $Wrapper)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s28take_wrapper_for_int_privateTf4x_n : $@convention(thin) (Int) -> ()
 // CHECK: [[INT:%.*]] = struct_extract [[WRAPPER]] : $Wrapper, #Wrapper.int
@@ -456,7 +456,7 @@ only(%wrapper : $Wrapper):
 // specializing reduces ARC traffic on account of the fact that the stripped
 // fields are non-trivial.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @take_pair_unused : $@convention(thin) (Pair) -> ()
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @take_pair_unused : $@convention(thin) (Pair) -> ()
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s16take_pair_unusedTf4d_n
 // CHECK: [[RESULT:%.*]] = apply [[FUNCTION]]()
@@ -492,7 +492,7 @@ only(%pair : $Pair):
 // specializing reduces ARC traffic on account of the fact that the stripped
 // fields are non-trivial.
 //
-// CHECK-LABEL: sil public_external [signature_optimized_thunk] [always_inline] @take_pair_unused_public_external : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil public_external [signature_optimized_thunk] [heuristic_always_inline] @take_pair_unused_public_external : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s32take_pair_unused_public_externalTf4d_n
 // CHECK: [[RESULT:%.*]] = apply [[FUNCTION]]()
@@ -528,7 +528,7 @@ only(%pair : $Pair):
 // specializing reduces ARC traffic on account of the fact that the stripped
 // fields are non-trivial.
 //
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @take_pair_unused_hidden : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @take_pair_unused_hidden : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s23take_pair_unused_hiddenTf4d_n
 // CHECK: [[RESULT:%.*]] = apply [[FUNCTION]]()
@@ -564,7 +564,7 @@ only(%pair : $Pair):
 // specializing reduces ARC traffic on account of the fact that the stripped
 // fields are non-trivial.
 //
-// CHECK-LABEL: sil private [signature_optimized_thunk] [always_inline] @take_pair_unused_private : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil private [signature_optimized_thunk] [heuristic_always_inline] @take_pair_unused_private : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s24take_pair_unused_privateTf4d_n
 // CHECK: [[RESULT:%.*]] = apply [[FUNCTION]]()
@@ -608,7 +608,7 @@ only(%pair : $Pair):
 // specializing reduces ARC traffic on account of the fact that the stripped
 // field is non-trivial.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @take_pair_for_klass1 : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @take_pair_for_klass1 : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s20take_pair_for_klass1Tf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[PAIR]] : $Pair, #Pair.klass1
@@ -647,7 +647,7 @@ only(%pair : $Pair):
 // specializing reduces ARC traffic on account of the fact that the stripped
 // field is non-trivial.
 //
-// CHECK-LABEL: sil public_external [signature_optimized_thunk] [always_inline] @take_pair_for_klass1_public_external : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil public_external [signature_optimized_thunk] [heuristic_always_inline] @take_pair_for_klass1_public_external : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s36take_pair_for_klass1_public_externalTf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[PAIR]] : $Pair, #Pair.klass1
@@ -688,7 +688,7 @@ only(%pair : $Pair):
 // avoiding passing the full Pair with its unused field klass2 avoids extraneous
 // ARC traffic around that field (i.e. #Pair.klass2).
 //
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @take_pair_for_klass1_hidden : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @take_pair_for_klass1_hidden : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s27take_pair_for_klass1_hiddenTf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[PAIR]] : $Pair, #Pair.klass1
@@ -729,7 +729,7 @@ only(%pair : $Pair):
 // (2) avoiding passing the full Pair with its unused field klass2 avoids
 // extraneous ARC traffic around that field (i.e. #Pair.klass2).
 //
-// CHECK-LABEL: sil private [signature_optimized_thunk] [always_inline] @take_pair_for_klass1_private : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil private [signature_optimized_thunk] [heuristic_always_inline] @take_pair_for_klass1_private : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s28take_pair_for_klass1_privateTf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[PAIR]] : $Pair, #Pair.klass1
@@ -776,7 +776,7 @@ only(%pair : $Pair):
 // specializing reduces ARC traffic on account of the fact that the stripped
 // field is non-trivial.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @take_pair_for_klass2 : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @take_pair_for_klass2 : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s20take_pair_for_klass2Tf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[PAIR]] : $Pair, #Pair.klass2
@@ -815,7 +815,7 @@ only(%pair : $Pair):
 // specializing reduces ARC traffic on account of the fact that the stripped
 // field is non-trivial.
 //
-// CHECK-LABEL: sil public_external [signature_optimized_thunk] [always_inline] @take_pair_for_klass2_public_external : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil public_external [signature_optimized_thunk] [heuristic_always_inline] @take_pair_for_klass2_public_external : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair)
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s36take_pair_for_klass2_public_externalTf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[PAIR]] : $Pair, #Pair.klass2
@@ -856,7 +856,7 @@ only(%pair : $Pair):
 // avoiding passing the full Pair with its unused field klass1 avoids extraneous
 // ARC traffic around that field (i.e. #Pair.klass1).
 //
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @take_pair_for_klass2_hidden : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @take_pair_for_klass2_hidden : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s27take_pair_for_klass2_hiddenTf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[PAIR]] : $Pair, #Pair.klass2
@@ -897,7 +897,7 @@ only(%pair : $Pair):
 // (2) avoiding passing the full Pair with its unused field klass1 avoids
 // extraneous ARC traffic around that field (i.e. #Pair.klass1).
 //
-// CHECK-LABEL: sil private [signature_optimized_thunk] [always_inline] @take_pair_for_klass2_private : $@convention(thin) (Pair) -> () {
+// CHECK-LABEL: sil private [signature_optimized_thunk] [heuristic_always_inline] @take_pair_for_klass2_private : $@convention(thin) (Pair) -> () {
 // CHECK: bb{{[0-9]*}}([[PAIR:%.*]] : $Pair):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s28take_pair_for_klass2_privateTf4x_n
 // CHECK: [[KLASS:%.*]] = struct_extract [[PAIR]] : $Pair, #Pair.klass2
@@ -1122,7 +1122,7 @@ only(%pair : $Pair):
 // result in specialization because there are only three (the heuristic for max
 // explosion size) live nodes in the type-tree.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3 : $@convention(thin) (Quintuple) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3 : $@convention(thin) (Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s35take_quintuple_for_klass1_through_3Tf4x_n : $@convention(thin) (Klass, Klass, Klass) -> () 
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
@@ -1165,7 +1165,7 @@ only(%quintuple : $Quintuple):
 // result in specialization because there are only three (the heuristic for max
 // explosion size) live nodes in the type-tree.
 //
-// CHECK-LABEL: sil public_external [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3_public_external : $@convention(thin) (Quintuple) -> () {
+// CHECK-LABEL: sil public_external [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3_public_external : $@convention(thin) (Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s51take_quintuple_for_klass1_through_3_public_externalTf4x_n : $@convention(thin) (Klass, Klass, Klass) -> () 
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
@@ -1208,7 +1208,7 @@ only(%quintuple : $Quintuple):
 // result in specialization because there are only three (the heuristic for max
 // explosion size) live nodes in the type-tree.
 //
-// CHECK-LABEL: sil shared [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3_shared : $@convention(thin) (Quintuple) -> () {
+// CHECK-LABEL: sil shared [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3_shared : $@convention(thin) (Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s42take_quintuple_for_klass1_through_3_sharedTf4x_n : $@convention(thin) (Klass, Klass, Klass) -> () 
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
@@ -1251,7 +1251,7 @@ only(%quintuple : $Quintuple):
 // result in specialization because there are only three (the heuristic for max
 // explosion size) live nodes in the type-tree.
 //
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3_hidden : $@convention(thin) (Quintuple) -> () {
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3_hidden : $@convention(thin) (Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s42take_quintuple_for_klass1_through_3_hiddenTf4x_n : $@convention(thin) (Klass, Klass, Klass) -> () 
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
@@ -1294,7 +1294,7 @@ only(%quintuple : $Quintuple):
 // result in specialization because there are only three (the heuristic for max
 // explosion size) live nodes in the type-tree.
 //
-// CHECK-LABEL: sil private [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3_private : $@convention(thin) (Quintuple) -> () {
+// CHECK-LABEL: sil private [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3_private : $@convention(thin) (Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s43take_quintuple_for_klass1_through_3_privateTf4x_n : $@convention(thin) (Klass, Klass, Klass) -> () 
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
@@ -1432,7 +1432,7 @@ only(%quintuple : $Quintuple):
 // live than the limit imposed by the heuristic, six because the specializing
 // the function will not result in a thunk.
 //
-// CHECK-LABEL: sil shared [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_4_shared : $@convention(thin) (Quintuple) -> () {
+// CHECK-LABEL: sil shared [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_4_shared : $@convention(thin) (Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s42take_quintuple_for_klass1_through_4_sharedTf4x_n : $@convention(thin) (Klass, Klass, Klass, Klass) -> () 
 // CHECK: [[KLASS4:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass4
@@ -1523,7 +1523,7 @@ only(%quintuple : $Quintuple):
 // live than the limit imposed by the heuristic, six because the specializing
 // the function will not result in a thunk.
 //
-// CHECK-LABEL: sil private [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_4_private : $@convention(thin) (Quintuple) -> () {
+// CHECK-LABEL: sil private [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_4_private : $@convention(thin) (Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[FUNCTION:%.*]] = function_ref @$s43take_quintuple_for_klass1_through_4_privateTf4x_n : $@convention(thin) (Klass, Klass, Klass, Klass) -> () 
 // CHECK: [[KLASS4:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass4
@@ -1579,7 +1579,7 @@ only(%quintuple : $Quintuple):
 // *should* result in specialization because there are only three live leaves in
 // the type tree after considering the owned-to-guaranteed transformation.
 //
-// CHECK-LABEL: sil [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5 : $@convention(thin) (@owned Quintuple) -> () {
+// CHECK-LABEL: sil [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5 : $@convention(thin) (@owned Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
 // CHECK: [[KLASS2:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass2
@@ -1628,7 +1628,7 @@ only(%quintuple : $Quintuple):
 // *should* result in specialization because there are only three live leaves in
 // the type tree after considering the owned-to-guaranteed transformation.
 //
-// CHECK-LABEL: sil public_external [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5_public_external : $@convention(thin) (@owned Quintuple) -> () {
+// CHECK-LABEL: sil public_external [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5_public_external : $@convention(thin) (@owned Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
 // CHECK: [[KLASS2:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass2
@@ -1678,7 +1678,7 @@ only(%quintuple : $Quintuple):
 // *should* result in specialization because there are only three live leaves
 // in the type tree after considering the owned-to-guaranteed transformation.
 //
-// CHECK-LABEL: sil shared [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5_shared : $@convention(thin) (@owned Quintuple) -> () {
+// CHECK-LABEL: sil shared [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5_shared : $@convention(thin) (@owned Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
 // CHECK: [[KLASS2:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass2
@@ -1728,7 +1728,7 @@ only(%quintuple : $Quintuple):
 // *should* result in specialization because there are only three live leaves
 // in the type tree after considering the owned-to-guaranteed transformation.
 //
-// CHECK-LABEL: sil hidden [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5_hidden : $@convention(thin) (@owned Quintuple) -> () {
+// CHECK-LABEL: sil hidden [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5_hidden : $@convention(thin) (@owned Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
 // CHECK: [[KLASS2:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass2
@@ -1778,7 +1778,7 @@ only(%quintuple : $Quintuple):
 // *should* result in specialization because there are only three live leaves
 // in the type tree after considering the owned-to-guaranteed transformation.
 //
-// CHECK-LABEL: sil private [signature_optimized_thunk] [always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5_private : $@convention(thin) (@owned Quintuple) -> () {
+// CHECK-LABEL: sil private [signature_optimized_thunk] [heuristic_always_inline] @take_quintuple_for_klass1_through_3_owned_klass4_through_5_private : $@convention(thin) (@owned Quintuple) -> () {
 // CHECK: bb{{[0-9]+}}([[QUINTUPLE:%.*]] : $Quintuple):
 // CHECK: [[KLASS3:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass3
 // CHECK: [[KLASS2:%.*]] = struct_extract [[QUINTUPLE]] : $Quintuple, #Quintuple.klass2
diff --git a/test/SILOptimizer/global_init_opt.swift b/test/SILOptimizer/global_init_opt.swift
index 28d66f9156930..6a85b0955a945 100644
--- a/test/SILOptimizer/global_init_opt.swift
+++ b/test/SILOptimizer/global_init_opt.swift
@@ -9,6 +9,7 @@ var gg: Int = {
 
 // Test that the compiler doesn't crash with a global C bitfield.
 var bitfield = S(a: 0, b: 0)
+var bitfield2 = S2(a: 0, b: 0)
 
 // CHECK-LABEL: sil @$s4test3cseSiyF
 // CHECK:   builtin "once"
diff --git a/test/SILOptimizer/globalopt_resilience.swift b/test/SILOptimizer/globalopt_resilience.swift
index 12a62efd2bea3..64a4c73395c26 100644
--- a/test/SILOptimizer/globalopt_resilience.swift
+++ b/test/SILOptimizer/globalopt_resilience.swift
@@ -37,13 +37,9 @@ public func cannotConvertToValueUse() {
 }
 
 // CHECK-LABEL: sil @$s4test23cannotConvertToValueUseyyF : $@convention(thin) () -> ()
-// CHECK: [[INT:%.*]] = integer_literal $Builtin.Int{{32|64}}, 27
-// CHECK: [[S1:%.*]] = struct $Int ([[INT]] : $Builtin.Int{{32|64}})
-// CHECK: [[S2:%.*]] = struct $ResilientStruct ([[S1]] : $Int)
-// CHECK: [[TMP:%.*]] = alloc_stack $ResilientStruct
-// CHECK: store [[S2]] to [[TMP]] : $*ResilientStruct
+// CHECK: [[GA:%.*]] = global_addr @$s4test15ResilientStructV9staticValACvpZ
 // CHECK: [[METHOD:%.*]] = function_ref @$s4test15ResilientStructV6methodyyF : $@convention(method) (@in_guaranteed ResilientStruct) -> ()
-// CHECK: apply [[METHOD]]([[TMP]]) : $@convention(method) (@in_guaranteed ResilientStruct) -> ()
+// CHECK: apply [[METHOD]]([[GA]]) : $@convention(method) (@in_guaranteed ResilientStruct) -> ()
 // CHECK: [[RESULT:%.*]] = tuple ()
 // CHECK: return [[RESULT]] : $()
 
diff --git a/test/SILOptimizer/high_level_licm.sil b/test/SILOptimizer/high_level_licm.sil
index 5c13725ca648f..9eead6190eb67 100644
--- a/test/SILOptimizer/high_level_licm.sil
+++ b/test/SILOptimizer/high_level_licm.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -high-level-licm | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -loop-invariant-code-motion | %FileCheck %s
 
 sil_stage canonical
 
diff --git a/test/SILOptimizer/hoist_destroy_addr.sil b/test/SILOptimizer/hoist_destroy_addr.sil
index 09e644cb6205e..b4d9b5e4c1c7a 100644
--- a/test/SILOptimizer/hoist_destroy_addr.sil
+++ b/test/SILOptimizer/hoist_destroy_addr.sil
@@ -1,9 +1,10 @@
-// RUN: %target-sil-opt -sil-print-types -opt-mode=none  -enable-sil-verify-all %s -compute-side-effects -destroy-addr-hoisting | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECKDEB --check-prefix=CHECK-DEB
-// RUN: %target-sil-opt -sil-print-types -opt-mode=speed -enable-sil-verify-all %s -compute-side-effects -destroy-addr-hoisting | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECKOPT --check-prefix=CHECK-OPT
+// RUN: %target-sil-opt -sil-print-types -enable-experimental-feature Lifetimes -opt-mode=none  -enable-sil-verify-all %s -compute-side-effects -destroy-addr-hoisting | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECKDEB --check-prefix=CHECK-DEB
+// RUN: %target-sil-opt -sil-print-types -enable-experimental-feature Lifetimes -opt-mode=speed -enable-sil-verify-all %s -compute-side-effects -destroy-addr-hoisting | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECKOPT --check-prefix=CHECK-OPT
 //
 // TODO: migrate the remaining tests from destroy_hoisting.sil.
 
 // REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
 
 sil_stage canonical
 
@@ -83,6 +84,10 @@ struct STXXITXXII {
 struct MoS: ~Copyable {}
 struct MoE: ~Copyable {}
 
+struct UnsafeMutablePointer<T> {
+  var _rawValue: Builtin.RawPointer
+}
+
 sil @unknown : $@convention(thin) () -> ()
 sil @use_S : $@convention(thin) (@in_guaranteed S) -> ()
 
@@ -683,7 +688,7 @@ entry(%instance : @owned $S):
   %store_scope = begin_access [modify] [static] %addr : $*S
   store %instance to [init] %store_scope : $*S
   end_access %store_scope : $*S
-  %load_scope = begin_access [read] [static] %addr : $*S
+  %load_scope = begin_access [modify] [static] %addr : $*S
   %value = load [copy] %load_scope : $*S
   end_access %load_scope : $*S
   destroy_addr %addr : $*S
@@ -702,7 +707,7 @@ entry(%instance : @owned $S):
   %store_scope = begin_access [modify] [static] %addr : $*S
   store %instance to [init] %store_scope : $*S
   end_access %store_scope : $*S
-  %load_scope = begin_access [read] [static] %addr : $*S
+  %load_scope = begin_access [modify] [static] %addr : $*S
   %value = load [copy] %load_scope : $*S
   %unknown = function_ref @unknown : $@convention(thin) () -> ()
   apply %unknown() : $@convention(thin) () -> ()
@@ -724,7 +729,7 @@ entry(%instance : @owned $S):
   %store_scope = begin_access [modify] [static] %addr : $*S
   store %instance to [init] %store_scope : $*S
   end_access %store_scope : $*S
-  %load_scope = begin_access [read] [static] %addr : $*S
+  %load_scope = begin_access [modify] [static] %addr : $*S
   %value = load [copy] %load_scope : $*S
   %unknown = function_ref @unknown : $@convention(thin) () -> ()
   apply %unknown() : $@convention(thin) () -> ()
@@ -745,7 +750,7 @@ entry(%instance : @owned $S):
   %store_scope = begin_access [modify] [static] %addr : $*S
   store %instance to [init] %store_scope : $*S
   end_access %store_scope : $*S
-  %load_scope = begin_access [read] [static] %addr : $*S
+  %load_scope = begin_access [modify] [static] %addr : $*S
   %field_addr = struct_element_addr %load_scope : $*S, #S.x
   %field = load [copy] %field_addr : $*X
   end_access %load_scope : $*S
@@ -767,9 +772,9 @@ entry(%instance : @owned $S):
   %store_scope = begin_access [modify] [static] %addr : $*S
   store %instance to [init] %store_scope : $*S
   end_access %store_scope : $*S
-  %outer = begin_access [read] [static] %addr : $*S
+  %outer = begin_access [modify] [static] %addr : $*S
   apply undef(%outer) : $@convention(thin) (@inout S) -> ()
-  %inner = begin_access [read] [static] %outer : $*S
+  %inner = begin_access [modify] [static] %outer : $*S
   %field_addr = struct_element_addr %inner : $*S, #S.x
   %field_addr_2 =  struct_element_addr %addr_2 : $*S, #S.x
   copy_addr %field_addr to [init] %field_addr_2 : $*X
@@ -794,9 +799,9 @@ entry(%instance : @owned $S):
   %store_scope = begin_access [modify] [static] %addr : $*S
   store %instance to [init] %store_scope : $*S
   end_access %store_scope : $*S
-  %outer = begin_access [read] [static] %addr : $*S
+  %outer = begin_access [modify] [static] %addr : $*S
   apply undef(%outer) : $@convention(thin) (@inout S) -> ()
-  %inner = begin_access [read] [static] %outer : $*S
+  %inner = begin_access [modify] [static] %outer : $*S
   copy_addr %inner to [init] %addr_2 : $*S
   end_access %inner : $*S
   destroy_addr %outer : $*S
@@ -1224,3 +1229,144 @@ bb0(%0 : @owned $Nontrivial):
   %14 = tuple ()
   return %14 : $()
 }
+
+struct Regular {
+  var storage: Builtin.NativeObject
+}
+struct NEGutless: ~Escapable {
+  let ptr: UnsafeRawPointer?
+}
+struct NEMarker : ~Escapable {}
+struct NEAggregate: ~Escapable {
+  var ne: NEGutless
+  let regular: Regular
+
+  @_lifetime(copy ne) init(ne: NEMarker)
+}
+
+// CHECK-LABEL: sil [ossa] @no_destructure_nonescapable : {{.*}} {
+// CHECK:       bb0([[AGGREGATE:%[^,]+]] :
+// CHECK:       destroy_addr [[AGGREGATE]]
+// CHECK-LABEL: } // end sil function 'no_destructure_nonescapable'
+sil [ossa] @no_destructure_nonescapable : $@convention(method) (@in NEAggregate) -> () {
+bb0(%aggregate : $*NEAggregate):
+  %regular = struct_element_addr %aggregate, #NEAggregate.regular
+  %regular_copy = alloc_stack $Regular
+  copy_addr %regular to [init] %regular_copy
+  destroy_addr %regular_copy
+  dealloc_stack %regular_copy
+  destroy_addr %aggregate
+  %retval = tuple ()
+  return %retval
+}
+
+struct NCGutless: ~Copyable {
+  let ptr: UnsafeRawPointer?
+}
+struct NCAggregate: ~Copyable {
+  var ne: NCGutless
+  let regular: Regular
+  deinit {}
+}
+
+// CHECK-LABEL: sil [ossa] @no_destructure_noncopyable : {{.*}} {
+// CHECK:       bb0([[AGGREGATE:%[^,]+]] :
+// CHECK:       destroy_addr [[AGGREGATE]]
+// CHECK-LABEL: } // end sil function 'no_destructure_noncopyable'
+sil [ossa] @no_destructure_noncopyable : $@convention(method) (@in NCAggregate) -> () {
+bb0(%aggregate : $*NCAggregate):
+  %regular = struct_element_addr %aggregate, #NCAggregate.regular
+  %regular_copy = alloc_stack $Regular
+  copy_addr %regular to [init] %regular_copy
+  destroy_addr %regular_copy
+  dealloc_stack %regular_copy
+  destroy_addr %aggregate
+  %retval = tuple ()
+  return %retval
+}
+
+// CHECK-LABEL: sil [ossa] @nohoist_ieda : {{.*}} {
+// CHECK:         [[IEDA:%[^,]+]] = init_enum_data_addr
+// CHECK:         tuple
+// CHECK-NEXT:    destroy_addr [[IEDA]]
+// CHECK-LABEL: } // end sil function 'nohoist_ieda'
+sil [ossa] @nohoist_ieda : $@convention(thin) () -> @out TwoCases {
+bb0(%out : $*TwoCases):
+  %ieda = init_enum_data_addr %out, #TwoCases.A!enumelt
+  apply undef(%ieda) : $@convention(thin) () -> @out X
+  %retval = tuple ()
+  destroy_addr %ieda
+  apply undef(%ieda) : $@convention(thin) () -> @out X
+  inject_enum_addr %out, #TwoCases.A!enumelt
+  return %retval
+}
+
+// CHECK-LABEL: sil [ossa] @nohoist_ieda_2 : {{.*}} {
+// CHECK:         [[IEDA:%[^,]+]] = init_enum_data_addr
+// CHECK:         tuple
+// CHECK:         [[CTM:%[^,]+]] = copyable_to_moveonlywrapper_addr [[IEDA]]
+// CHECK:         [[MTC:%[^,]+]] = moveonlywrapper_to_copyable_addr [[CTM]]
+// CHECK-NEXT:    destroy_addr [[MTC]]
+// CHECK-LABEL: } // end sil function 'nohoist_ieda_2'
+sil [ossa] @nohoist_ieda_2 : $@convention(thin) () -> @out TwoCases {
+bb0(%out : $*TwoCases):
+  %ieda = init_enum_data_addr %out, #TwoCases.A!enumelt
+  apply undef(%ieda) : $@convention(thin) () -> @out X
+  %retval = tuple ()
+  %ctm = copyable_to_moveonlywrapper_addr %ieda
+  %mtc = moveonlywrapper_to_copyable_addr %ctm
+  destroy_addr %mtc
+  apply undef(%ieda) : $@convention(thin) () -> @out X
+  inject_enum_addr %out, #TwoCases.A!enumelt
+  return %retval
+}
+
+// CHECK-LABEL: sil [ossa] @nofold_read_access_load : {{.*}} {
+// CHECK:         load [copy]
+// CHECK-LABEL: } // end sil function 'nofold_read_access_load'
+sil [ossa] @nofold_read_access_load : $@convention(thin) (@in X) -> () {
+entry(%c_addr : $*X):
+  %c_access = begin_access [dynamic] [read] %c_addr
+  %c = load [copy] %c_access
+  end_access %c_access
+  destroy_addr %c_addr
+  apply undef(%c) : $@convention(thin) (@owned X) -> ()
+  %retval = tuple ()
+  return %retval
+}
+
+// CHECK-LABEL: sil [ossa] @nofold_read_access_copy_addr : {{.*}} {
+// CHECK:         copy_addr {{%[^,]+}} to [init]
+// CHECK-LABEL: } // end sil function 'nofold_read_access_copy_addr'
+sil [ossa] @nofold_read_access_copy_addr : $@convention(thin) (@in X) -> () {
+entry(%c_addr : $*X):
+  %stack = alloc_stack $X
+  %c_access = begin_access [dynamic] [read] %c_addr
+  copy_addr %c_access to [init] %stack
+  end_access %c_access
+  destroy_addr %c_addr
+  apply undef(%stack) : $@convention(thin) (@in X) -> ()
+  dealloc_stack %stack
+  %retval = tuple ()
+  return %retval
+}
+
+// CHECK-LABEL: sil [ossa] @no_hoist_into_load_borrow_scope : {{.*}} {
+// CHECK:         end_borrow
+// CHECK-NEXT:    destroy_addr
+// CHECK-LABEL: } // end sil function 'no_hoist_into_load_borrow_scope'
+sil [ossa] @no_hoist_into_load_borrow_scope : $@convention(thin) (@in X) -> () {
+entry(%c_addr_in : $*X):
+  %c_ptr = address_to_pointer [stack_protection] %c_addr_in to $Builtin.RawPointer
+  %c_up = struct $UnsafeMutablePointer<X> (%c_ptr)
+  %c_ptr_2 = struct_extract %c_up, #UnsafeMutablePointer._rawValue // user: %45
+  %c_addr = pointer_to_address %c_ptr_2 to [strict] $*X
+  %c_borrow = load_borrow %c_addr
+  apply undef(%c_borrow) : $@convention(thin) (@guaranteed X) -> ()
+  %c_copy = load [copy] %c_addr_in
+  end_borrow %c_borrow
+  %retval = tuple ()
+  destroy_addr %c_addr_in
+  destroy_value %c_copy
+  return %retval
+}
diff --git a/test/SILOptimizer/ignore-always-inline.sil b/test/SILOptimizer/ignore-always-inline.sil
index 49d98e870a4f1..c7ea1aad091ea 100644
--- a/test/SILOptimizer/ignore-always-inline.sil
+++ b/test/SILOptimizer/ignore-always-inline.sil
@@ -19,10 +19,10 @@ bb0:
 
 sil @foobar : $@convention(thin) () -> ()
 
-// callee is "expensive" enough to not get inlined unless [always_inline] is used
-// REGULAR: sil [always_inline] [Osize] @callee
-// IGNORED: sil [always_inline] [Osize] @callee
-sil [always_inline] [Osize] @callee : $@convention(thin) () -> () {
+// callee is "expensive" enough to not get inlined unless [heuristic_always_inline] is used
+// REGULAR: sil [heuristic_always_inline] [Osize] @callee
+// IGNORED: sil [heuristic_always_inline] [Osize] @callee
+sil [heuristic_always_inline] [Osize] @callee : $@convention(thin) () -> () {
 bb0:
   %d1 = function_ref @foobar : $@convention(thin) () -> ()
   apply %d1() : $@convention(thin) () -> ()
diff --git a/test/SILOptimizer/infinite_recursion.swift b/test/SILOptimizer/infinite_recursion.swift
index 42e64ce15ff2f..943863d4b860b 100644
--- a/test/SILOptimizer/infinite_recursion.swift
+++ b/test/SILOptimizer/infinite_recursion.swift
@@ -352,3 +352,11 @@ func recursionMatchingTypeArgs2<T: P, V: P>(_ t: T.Type, _ v: V.Type) {
   recursionMatchingTypeArgs2(T.self, V.self) // expected-warning {{function call causes an infinite recursion}}
 }
 
+func testNoInfiniteRecursionWithOverloadingOnOptional() {
+  func test(handler: @escaping (Bool) -> Void) {
+  }
+
+  func test(handler: ((Bool) -> Void)?) {
+    test(handler: handler ?? { _ in }) // Ok
+  }
+}
diff --git a/test/SILOptimizer/init_accessor_in_constrained_extensions.swift b/test/SILOptimizer/init_accessor_in_constrained_extensions.swift
new file mode 100644
index 0000000000000..a8337ee955b4b
--- /dev/null
+++ b/test/SILOptimizer/init_accessor_in_constrained_extensions.swift
@@ -0,0 +1,73 @@
+// RUN: %target-swift-frontend -Xllvm -sil-print-types -Xllvm -sil-print-after=definite-init -emit-sil -module-name assign_or_init_lowering %s -o /dev/null 2>&1 | %FileCheck %s
+
+struct S1<T> {
+}
+
+extension S1 where T == Int {
+  class Test {
+    var test1: Int {
+      init(initialValue) { }
+      set {}
+      get { 0 }
+    }
+
+    var test2: T {
+      init(initialValue) { }
+      set {}
+      get { 0 }
+    }
+
+    // CHECK-LABEL: sil hidden [ossa] @$s23assign_or_init_lowering2S1VAASiRszlE4TestCAEySi_Gycfc : $@convention(method) (@owned S1<Int>.Test) -> @owned S1<Int>.Test
+    //
+    // CHECK: [[TEST1_INIT_REF:%.*]] = function_ref @$s23assign_or_init_lowering2S1VAASiRszlE4TestC5test1Sivi : $@convention(thin) (Int, @thick S1<Int>.Test.Type) -> ()
+    // CHECK-NEXT: [[SELF:%.*]] = value_metatype $@thick S1<Int>.Test.Type, {{.*}} : $S1<Int>.Test
+    // CHECK-NEXT: [[TEST1_INIT_REF_WITH_SELF_APPLIED:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[TEST1_INIT_REF]]([[SELF]]) : $@convention(thin) (Int, @thick S1<Int>.Test.Type) -> ()
+    // CHECK: assign_or_init [init] #S1.Test.test1, self {{.*}} : $S1<Int>.Test, value {{.*}} : $Int, init [[TEST1_INIT_REF_WITH_SELF_APPLIED]] : $@noescape @callee_guaranteed (Int) -> (), set {{.*}} : $@noescape @callee_guaranteed (Int) -> ()
+    //
+    // CHECK: [[TEST2_INIT_REF:%.*]] = function_ref @$s23assign_or_init_lowering2S1VAASiRszlE4TestC5test2Sivi : $@convention(thin) (Int, @thick S1<Int>.Test.Type) -> ()
+    // CHECK-NEXT: [[SELF:%.*]] = value_metatype $@thick S1<Int>.Test.Type, {{.*}} : $S1<Int>.Test
+    // CHECK-NEXT: [[TEST2_INIT_REF_WITH_SELF_APPLIED:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[TEST2_INIT_REF]]([[SELF]]) : $@convention(thin) (Int, @thick S1<Int>.Test.Type) -> ()
+    // CHECK: assign_or_init [init] #S1.Test.test2, self {{.*}} : $S1<Int>.Test, value {{.*}} : $Int, init [[TEST2_INIT_REF_WITH_SELF_APPLIED]] : $@noescape @callee_guaranteed (Int) -> (), set {{.*}} : $@noescape @callee_guaranteed (Int) -> ()
+    // CHECK: } // end sil function '$s23assign_or_init_lowering2S1VAASiRszlE4TestCAEySi_Gycfc'
+    init() {
+      test1 = 0
+      test2 = 1
+    }
+  }
+}
+
+struct S2<T, U> {
+}
+
+extension S2 where T == Int {
+  class Test {
+    var test1: T {
+      init(initialValue) { }
+      set {}
+      get { 0 }
+    }
+
+    var test2: U {
+      init(initialValue) { }
+      set {}
+      get { fatalError() }
+    }
+
+    // CHECK-LABEL: sil hidden [ossa] @$s23assign_or_init_lowering2S2VAASiRszrlE4TestC1uAEySiq__Gq__tcfc : $@convention(method) <T, U where T == Int> (@in U, @owned S2<Int, U>.Test) -> @owned S2<Int, U>.Test {
+    //
+    // CHECK: [[TEST1_INIT_REF:%.*]] = function_ref @$s23assign_or_init_lowering2S2VAASiRszrlE4TestC5test1Sivi : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == Int> (Int, @thick S2<Int, τ_0_1>.Test.Type) -> ()
+    // CHECK-NEXT: [[SELF:%.*]] = value_metatype $@thick S2<Int, U>.Test.Type, {{.*}} : $S2<Int, U>.Test
+    // CHECK-NEXT: [[TEST1_INIT_REF_WITH_SELF_APPLIED:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[TEST1_INIT_REF]]<Int, U>([[SELF]]) : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == Int> (Int, @thick S2<Int, τ_0_1>.Test.Type) -> ()
+    // CHECK: assign_or_init [init] #S2.Test.test1, self {{.*}} : $S2<Int, U>.Test, value {{.*}} : $Int, init [[TEST1_INIT_REF_WITH_SELF_APPLIED]] : $@noescape @callee_guaranteed (Int) -> (), set {{.*}} : $@noescape @callee_guaranteed (Int) -> ()
+    //
+    // CHECK: [[TEST2_INIT_REF:%.*]] = function_ref @$s23assign_or_init_lowering2S2VAASiRszrlE4TestC5test2q_vi : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == Int> (@in τ_0_1, @thick S2<Int, τ_0_1>.Test.Type) -> ()
+    // CHECK-NEXT: [[SELF:%.*]] = value_metatype $@thick S2<Int, U>.Test.Type, {{.*}} : $S2<Int, U>.Test
+    // CHECK-NEXT: [[TEST2_INIT_REF_WITH_SELF_APPLIED:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[TEST2_INIT_REF]]<Int, U>([[SELF]]) : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == Int> (@in τ_0_1, @thick S2<Int, τ_0_1>.Test.Type) -> ()
+    // CHECK: assign_or_init [init] #S2.Test.test2, self {{.*}} : $S2<Int, U>.Test, value {{.*}} : $*U, init [[TEST2_INIT_REF_WITH_SELF_APPLIED]] : $@noescape @callee_guaranteed (@in U) -> (), set {{.*}} : $@noescape @callee_guaranteed (@in U) -> ()
+    // CHECK: } // end sil function '$s23assign_or_init_lowering2S2VAASiRszrlE4TestC1uAEySiq__Gq__tcfc'
+    init(u: U) {
+      test1 = 0
+      test2 = u
+    }
+  }
+}
diff --git a/test/SILOptimizer/init_accessors.sil b/test/SILOptimizer/init_accessors.sil
index c7df2e3e4c99e..cab1e0b31ead6 100644
--- a/test/SILOptimizer/init_accessors.sil
+++ b/test/SILOptimizer/init_accessors.sil
@@ -39,9 +39,9 @@ bb0(%0 : $Int, %1 : $*Test):
 }
 
 // CHECK-LABEL: sil hidden [ossa] @$s14init_accessors4TestV1vACSi_tcfC : $@convention(method) (Int, @thin Test.Type) -> Test
+// CHECK: [[SELF_REF:%.*]] = begin_access [modify] [unknown] [[SELF:%.*]] : $*Test
 // CHECK: [[INIT_REF:%.*]] = function_ref @$s14init_accessors4TestV1xSivi : $@convention(thin) (Int) -> @out Int
-// CHECK: [[SELF_REF:%.*]] = begin_access [modify] [dynamic] [[SELF:%.*]] : $*Test
-// CHECK-NEXT: [[FIELD_REF:%.*]] = struct_element_addr [[SELF_REF]] : $*Test, #Test._x
+// CHECK: [[FIELD_REF:%.*]] = struct_element_addr [[SELF_REF]] : $*Test, #Test._x
 // CHECK-NEXT: {{.*}} = apply [[INIT_REF]]([[FIELD_REF]], %0) : $@convention(thin) (Int) -> @out Int
 sil hidden [ossa] @$s14init_accessors4TestV1vACSi_tcfC : $@convention(method) (Int, @thin Test.Type) -> Test {
 bb0(%0 : $Int, %1 : $@thin Test.Type):
diff --git a/test/SILOptimizer/init_accessors.swift b/test/SILOptimizer/init_accessors.swift
index e4481f6d5fa80..d601cf7f2b032 100644
--- a/test/SILOptimizer/init_accessors.swift
+++ b/test/SILOptimizer/init_accessors.swift
@@ -41,10 +41,11 @@ struct TestInit {
   }
 
   // CHECK-LABEL: sil hidden [ossa] @$s14init_accessors8TestInitV1x1yACSi_SitcfC : $@convention(method) (Int, Int, @thin TestInit.Type) -> TestInit
+  // CHECK: end_access
+  // CHECK: [[SELF_VALUE:%.*]] = begin_access [modify] [static] {{.*}} : $*TestInit
   // CHECK: // function_ref TestInit.point.init
   // CHECK-NEXT: [[INIT_ACCESSOR_FN:%.*]] = function_ref @$s14init_accessors8TestInitV5pointSi_Sitvi : $@convention(thin) (Int, Int, @inout Int, @thin TestInit.Type) -> (@out Int, @out (Int, Int))
   // CHECK-NEXT: [[INIT_ACCESSOR:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[INIT_ACCESSOR_FN]](%2) : $@convention(thin) (Int, Int, @inout Int, @thin TestInit.Type) -> (@out Int, @out (Int, Int))
-  // CHECK: [[SELF_VALUE:%.*]] = begin_access [modify] [dynamic] {{.*}} : $*TestInit
   // CHECK: [[Y_REF:%.*]] = struct_element_addr [[SELF_VALUE]] : $*TestInit, #TestInit.y
   // CHECK-NEXT: [[FULL_REF:%.*]] = struct_element_addr [[SELF_VALUE]] : $*TestInit, #TestInit.full
   // CHECK-NEXT: ([[X_VAL:%.*]], [[Y_VAL:%.*]]) = destructure_tuple {{.*}} : $(Int, Int)
@@ -71,10 +72,13 @@ struct TestSetter {
   }
 
   // CHECK-LABEL: sil hidden [ossa] @$s14init_accessors10TestSetterV1x1yACSi_SitcfC : $@convention(method) (Int, Int, @thin TestSetter.Type) -> TestSetter
+  // CHECK: [[AS:%.*]] = alloc_stack
+  // CHECK: end_access
+  // CHECK: end_access
+  // CHECK: [[SELF:%.*]] = begin_access [modify] [static] [[AS]] : $*TestSetter
   // CHECK: [[INIT_ACCESSOR_FN:%.*]] = function_ref @$s14init_accessors10TestSetterV5pointSi_Sitvi : $@convention(thin) (Int, Int, @inout Int, @inout Int, @thin TestSetter.Type) -> ()
   // CHECK: [[INIT_ACCESSOR:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[INIT_ACCESSOR_FN]](%2) : $@convention(thin) (Int, Int, @inout Int, @inout Int, @thin TestSetter.Type) -> ()
-  // CHECK: [[SELF:%.*]] = begin_access [modify] [dynamic] %14 : $*TestSetter
-  // CHECK-NEXT: ([[X:%.*]], [[Y:%.*]]) = destructure_tuple {{.*}} : $(Int, Int)
+  // CHECK:      ([[X:%.*]], [[Y:%.*]]) = destructure_tuple {{.*}} : $(Int, Int)
   // CHECK-NEXT: [[X_REF:%.*]] = struct_element_addr [[SELF]] : $*TestSetter, #TestSetter.x
   // CHECK-NEXT: [[Y_REF:%.*]] = struct_element_addr [[SELF]] : $*TestSetter, #TestSetter.y
   // CHECK-NEXT: {{.*}} = apply [[INIT_ACCESSOR]]([[X]], [[Y]], [[X_REF]], [[Y_REF]]) : $@noescape @callee_guaranteed (Int, Int, @inout Int, @inout Int) -> ()
@@ -204,17 +208,18 @@ struct TestNoInitAndInit {
 
   // CHECK-LABEL: sil hidden [ossa] @$s14init_accessors013TestNoInitAndE0V1x1yACSi_SitcfC : $@convention(method) (Int, Int, @thin TestNoInitAndInit.Type) -> TestNoInitAndInit
   //
+  // CHECK: end_access
+  // CHECK: [[SELF_REF:%.*]] = begin_access [modify] [static] {{.*}} : $*TestNoInitAndInit
   // CHECK: [[INIT_REF_FN:%.*]] = function_ref @$s14init_accessors013TestNoInitAndE0V6pointXSivi : $@convention(thin) (Int, @inout Int, @thin TestNoInitAndInit.Type) -> ()
   // CHECK: [[INIT_REF:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[INIT_REF_FN]](%2) : $@convention(thin) (Int, @inout Int, @thin TestNoInitAndInit.Type) -> ()
-  // CHECK: [[SELF_REF:%.*]] = begin_access [modify] [dynamic] {{.*}} : $*TestNoInitAndInit
-  // CHECK-NEXT: [[X_REF:%.*]] = struct_element_addr [[SELF_REF]] : $*TestNoInitAndInit, #TestNoInitAndInit.x
+  // CHECK:      [[X_REF:%.*]] = struct_element_addr [[SELF_REF]] : $*TestNoInitAndInit, #TestNoInitAndInit.x
   // CHECK-NEXT: {{.*}} = apply [[INIT_REF]](%0, [[X_REF]]) : $@noescape @callee_guaranteed (Int, @inout Int) -> ()
   // CHECK-NEXT: end_access [[SELF_REF]] : $*TestNoInitAndInit
   //
+  // CHECK: [[SELF_REF:%.*]] = begin_access [modify] [static] {{.*}} : $*TestNoInitAndInit
   // CHECK: [[INIT_REF_FN:%.*]] = function_ref @$s14init_accessors013TestNoInitAndE0V6pointYSivi : $@convention(thin) (Int, @thin TestNoInitAndInit.Type) -> @out Int
   // CHECK: [[INIT_REF:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[INIT_REF_FN]](%2) : $@convention(thin) (Int, @thin TestNoInitAndInit.Type) -> @out Int
-  // CHECK: [[SELF_REF:%.*]] = begin_access [modify] [dynamic] {{.*}} : $*TestNoInitAndInit
-  // CHECK-NEXT: [[Y_REF:%.*]] = struct_element_addr [[SELF_REF]] : $*TestNoInitAndInit, #TestNoInitAndInit.y
+  // CHECK:      [[Y_REF:%.*]] = struct_element_addr [[SELF_REF]] : $*TestNoInitAndInit, #TestNoInitAndInit.y
   // CHECK-NEXT: {{.*}} = apply [[INIT_REF]]([[Y_REF]], %1) : $@noescape @callee_guaranteed (Int) -> @out Int
   // CHECK-NEXT: end_access [[SELF_REF]] : $*TestNoInitAndInit
   init(x: Int, y: Int) {
diff --git a/test/SILOptimizer/init_static_globals.sil b/test/SILOptimizer/init_static_globals.sil
index 21e58e0cfc1c5..7211f51bea9e6 100644
--- a/test/SILOptimizer/init_static_globals.sil
+++ b/test/SILOptimizer/init_static_globals.sil
@@ -1,6 +1,7 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -initialize-static-globals | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -enable-experimental-feature RawLayout -initialize-static-globals | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_RawLayout
 
 sil_stage canonical
 
@@ -36,6 +37,21 @@ struct TwoFields {
   let b: Int32
 }
 
+struct WithOptionalEnum {
+  var e: E?
+}
+
+enum E {
+  case a
+  case b
+}
+
+@_rawLayout(like: Int32)
+struct Raw: ~Copyable {}
+
+@_rawLayout(likeArrayOf: Int32, count: 2)
+struct RawArray: ~Copyable {}
+
 let nontrivialglobal: TClass
 
 // CHECK-LABEL: sil_global hidden [let] @$trivialglobal : $TStruct = {
@@ -98,8 +114,6 @@ sil_global [let] @g7 : $TwoFields
 // CHECK-NEXT:  }
 sil_global [let] @g8 : $UnsafePointer<Int32>
 
-sil_global [let] @g9 : $TwoFields
-
 // CHECK-LABEL: sil_global [let] @inline_array1 : $InlineArray<3, Int32> = {
 // CHECK-NEXT:    %0 = integer_literal $Builtin.Int32, 1
 // CHECK-NEXT:    %1 = struct $Int32 (%0)
@@ -107,7 +121,8 @@ sil_global [let] @g9 : $TwoFields
 // CHECK-NEXT:    %3 = struct $Int32 (%2)
 // CHECK-NEXT:    %4 = integer_literal $Builtin.Int32, 3
 // CHECK-NEXT:    %5 = struct $Int32 (%4)
-// CHECK-NEXT:    %initval = vector (%1, %3, %5)
+// CHECK-NEXT:    %6 = vector (%1, %3, %5)
+// CHECK-NEXT:    %initval = struct $InlineArray<3, Int32> (%6)
 // CHECK-NEXT:  }
 sil_global [let] @inline_array1 : $InlineArray<3, Int32>
 
@@ -127,7 +142,8 @@ sil_global [let] @inline_array1 : $InlineArray<3, Int32>
 // CHECK-NEXT:    %12 = integer_literal $Builtin.Int32, 60
 // CHECK-NEXT:    %13 = struct $Int32 (%12)
 // CHECK-NEXT:    %14 = tuple (%11, %13)
-// CHECK-NEXT:    %initval = vector (%4, %9, %14)
+// CHECK-NEXT:    %15 = vector (%4, %9, %14)
+// CHECK-NEXT:    %initval = struct $InlineArray<3, (Int32, Int32)> (%15)
 // CHECK-NEXT:  }
 sil_global [let] @inline_array2 : $InlineArray<3, (Int32, Int32)>
 
@@ -143,8 +159,46 @@ sil_global [let] @empty_inline_array : $InlineArray<0, Int32>
 // CHECK-LABEL: sil_global [let] @inline_array_empty_elements : $InlineArray<3, ()>{{$}}
 sil_global [let] @inline_array_empty_elements : $InlineArray<3, ()>
 
+// CHECK-LABEL: sil_global [let] @gint : $Int32 = {
+// CHECK-NEXT:    %0 = integer_literal $Builtin.Int32, 1
+// CHECK-NEXT:    %initval = struct $Int32 (%0)
+// CHECK-NEXT:  }
 sil_global [let] @gint : $Int32
 
+// CHECK-LABEL: sil_global [let] @graw : $Raw = {
+// CHECK-NEXT:    %0 = integer_literal $Builtin.Int32, 1
+// CHECK-NEXT:    %initval = struct $Int32 (%0)
+// CHECK-NEXT:  }
+sil_global [let] @graw: $Raw
+
+// CHECK-LABEL: sil_global [let] @graw2 : $Raw{{$}}
+sil_global [let] @graw2: $Raw
+
+// CHECK-LABEL: sil_global [let] @grawArray : $RawArray{{$}}
+sil_global [let] @grawArray: $RawArray
+
+// CHECK-LABEL: sil_global [let] @gIndirectNone : $Optional<TwoFields> = {
+// CHECK-NEXT:    %initval = enum $Optional<TwoFields>, #Optional.none!enumelt
+// CHECK-NEXT:  }
+sil_global [let] @gIndirectNone: $Optional<TwoFields>
+
+// CHECK-LABEL: sil_global [let] @gIndirectSome : $Optional<TwoFields> = {
+// CHECK-NEXT:    %0 = integer_literal $Builtin.Int32, 11
+// CHECK-NEXT:    %1 = struct $Int32 (%0)
+// CHECK-NEXT:    %2 = integer_literal $Builtin.Int32, 10
+// CHECK-NEXT:    %3 = struct $Int32 (%2)
+// CHECK-NEXT:    %4 = struct $TwoFields (%1, %3)
+// CHECK-NEXT:    %initval = enum $Optional<TwoFields>, #Optional.some!enumelt, %4
+// CHECK-NEXT:  }
+sil_global [let] @gIndirectSome: $Optional<TwoFields>
+
+// CHECK-LABEL: sil_global [let] @structWithOptionalEnum : $WithOptionalEnum = {
+// CHECK-NEXT:    %0 = enum $E, #E.a!enumelt
+// CHECK-NEXT:    %1 = enum $Optional<E>, #Optional.some!enumelt, %0
+// CHECK-NEXT:    %initval = struct $WithOptionalEnum (%1)
+// CHECK-NEXT:  }
+sil_global [let] @structWithOptionalEnum : $WithOptionalEnum
+
 sil @unknownfunc : $@convention(thin) () -> ()
 
 // CHECK-LABEL: sil [global_init_once_fn] [ossa] @globalinit_trivialglobal_func :
@@ -282,34 +336,6 @@ bb0:
   return %10 : $()
 }
 
-// CHECK-LABEL: sil [global_init_once_fn] [ossa] @merge_stores_but_no_global_init :
-// CHECK:         [[GA:%.*]] = global_addr @g9 : $*TwoFields
-// CHECK:         [[L10:%.*]] = integer_literal $Builtin.Int32, 10
-// CHECK:         [[I10:%.*]] = struct $Int32 ([[L10]])
-// CHECK:         [[L11:%.*]] = integer_literal $Builtin.Int32, 11
-// CHECK:         [[I11:%.*]] = struct $Int32 ([[L11]])
-// CHECK:         [[TF:%.*]] = struct $TwoFields ([[I11]], [[I10]])
-// CHECK:         store [[TF]] to [trivial] [[GA]]
-// CHECK:         function_ref
-// CHECK:       } // end sil function 'merge_stores_but_no_global_init'
-sil [global_init_once_fn] [ossa] @merge_stores_but_no_global_init : $@convention(c) () -> () {
-bb0:
-  alloc_global @g9
-  %1 = global_addr @g9 : $*TwoFields
-  %2 = integer_literal $Builtin.Int32, 10
-  %3 = struct $Int32 (%2 : $Builtin.Int32)
-  %4 = struct_element_addr %1 : $*TwoFields, #TwoFields.b
-  store %3 to [trivial] %4 : $*Int32
-  %6 = integer_literal $Builtin.Int32, 11
-  %7 = struct $Int32 (%6 : $Builtin.Int32)
-  %8 = struct_element_addr %1 : $*TwoFields, #TwoFields.a
-  store %7 to [trivial] %8 : $*Int32
-  %f = function_ref @unknownfunc : $@convention(thin) () -> ()
-  %a = apply %f() : $@convention(thin) () -> ()
-  %10 = tuple ()
-  return %10 : $()
-}
-
 // CHECK-LABEL: sil [global_init_once_fn] [ossa] @globalinit_wrong_separate_stores :
 // CHECK:         alloc_global
 // CHECK:         store
@@ -350,15 +376,14 @@ bb0(%0 : $Builtin.RawPointer):
 
 // CHECK-LABEL: sil [global_init_once_fn] [ossa] @globalinit_inline_array :
 // CHECK-NOT:     alloc_global
-// CHECK-NOT:     alloc_stack
-// CHECK-NOT:     store
+// CHECK-NOT:     global_addr
 // CHECK:       } // end sil function 'globalinit_inline_array'
 sil [global_init_once_fn] [ossa] @globalinit_inline_array : $@convention(c) (Builtin.RawPointer) -> () {
 bb0(%0 : $Builtin.RawPointer):
   alloc_global @inline_array1
   %2 = global_addr @inline_array1 : $*InlineArray<3, Int32>
-  %3 = alloc_stack $InlineArray<3, Int32>
-  %4 = unchecked_addr_cast %3 to $*Int32
+  %3 = alloc_stack $Builtin.FixedArray<3, Int32>
+  %4 = vector_base_addr %3
   %5 = integer_literal $Builtin.Int32, 1
   %6 = struct $Int32 (%5)
   store %6 to [trivial] %4
@@ -373,23 +398,23 @@ bb0(%0 : $Builtin.RawPointer):
   %16 = struct $Int32 (%15)
   store %16 to [trivial] %14
   %18 = load [trivial] %3
+  %19 = struct $InlineArray<3, Int32> (%18)
   dealloc_stack %3
-  store %18 to [trivial] %2
+  store %19 to [trivial] %2
   %21 = tuple ()
   return %21
 }
 
 // CHECK-LABEL: sil [global_init_once_fn] [ossa] @globalinit_inline_array_of_tuples :
 // CHECK-NOT:     alloc_global
-// CHECK-NOT:     alloc_stack
-// CHECK-NOT:     store
+// CHECK-NOT:     global_addr
 // CHECK:       } // end sil function 'globalinit_inline_array_of_tuples'
 sil [global_init_once_fn] [ossa] @globalinit_inline_array_of_tuples : $@convention(c) (Builtin.RawPointer) -> () {
 bb0(%0 : $Builtin.RawPointer):
   alloc_global @inline_array2
   %2 = global_addr @inline_array2 : $*InlineArray<3, (Int32, Int32)>
-  %3 = alloc_stack $InlineArray<3, (Int32, Int32)>
-  %4 = unchecked_addr_cast %3 to $*(Int32, Int32)
+  %3 = alloc_stack $Builtin.FixedArray<3, (Int32, Int32)>
+  %4 = vector_base_addr %3
   %5 = tuple_element_addr %4, 0
   %6 = tuple_element_addr %4, 1
   %7 = integer_literal $Builtin.Int32, 10
@@ -419,8 +444,9 @@ bb0(%0 : $Builtin.RawPointer):
   %31 = struct $Int32 (%30)
   store %31 to [trivial] %26
   %33 = load [trivial] %3
+  %34 = struct $InlineArray<3, (Int32, Int32)> (%33)
   dealloc_stack %3
-  store %33 to [trivial] %2
+  store %34 to [trivial] %2
   %36 = tuple ()
   return %36
 }
@@ -434,8 +460,8 @@ sil [global_init_once_fn] [ossa] @no_globalinit_double_store: $@convention(c) (B
 bb0(%0 : $Builtin.RawPointer):
   alloc_global @inline_array3
   %2 = global_addr @inline_array3 : $*InlineArray<2, Int32>
-  %3 = alloc_stack $InlineArray<2, Int32>
-  %4 = unchecked_addr_cast %3 to $*Int32
+  %3 = alloc_stack $Builtin.FixedArray<2, Int32>
+  %4 = vector_base_addr %3
   %5 = integer_literal $Builtin.Int32, 1
   %6 = struct $Int32 (%5)
   store %6 to [trivial] %4
@@ -446,8 +472,9 @@ bb0(%0 : $Builtin.RawPointer):
   store %11 to [trivial] %9
   store %6 to [trivial] %9
   %18 = load [trivial] %3
+  %19 = struct $InlineArray<2, Int32> (%18)
   dealloc_stack %3
-  store %18 to [trivial] %2
+  store %19 to [trivial] %2
   %21 = tuple ()
   return %21
 }
@@ -461,8 +488,8 @@ sil [global_init_once_fn] [ossa] @no_globalinit_extra_load: $@convention(c) (Bui
 bb0(%0 : $Builtin.RawPointer):
   alloc_global @inline_array4
   %2 = global_addr @inline_array4 : $*InlineArray<2, Int32>
-  %3 = alloc_stack $InlineArray<2, Int32>
-  %4 = unchecked_addr_cast %3 to $*Int32
+  %3 = alloc_stack $Builtin.FixedArray<2, Int32>
+  %4 = vector_base_addr %3
   %5 = integer_literal $Builtin.Int32, 1
   %6 = struct $Int32 (%5)
   store %6 to [trivial] %4
@@ -471,23 +498,23 @@ bb0(%0 : $Builtin.RawPointer):
   %10 = load [trivial] %4
   store %10 to [trivial] %9
   %18 = load [trivial] %3
+  %19 = struct $InlineArray<2, Int32> (%18)
   dealloc_stack %3
-  store %18 to [trivial] %2
+  store %19 to [trivial] %2
   %21 = tuple ()
   return %21
 }
 
-// CHECK-LABEL: sil [global_init_once_fn] [ossa] @no_globalinit_no_load :
-// CHECK:         alloc_global
-// CHECK:         alloc_stack
-// CHECK:         store
-// CHECK:       } // end sil function 'no_globalinit_no_load'
-sil [global_init_once_fn] [ossa] @no_globalinit_no_load: $@convention(c) (Builtin.RawPointer) -> () {
+// CHECK-LABEL: sil [global_init_once_fn] [ossa] @globalinit_no_load :
+// CHECK-NOT:     alloc_global
+// CHECK-NOT:     global_addr
+// CHECK:       } // end sil function 'globalinit_no_load'
+sil [global_init_once_fn] [ossa] @globalinit_no_load: $@convention(c) (Builtin.RawPointer) -> () {
 bb0(%0 : $Builtin.RawPointer):
   alloc_global @gint
   %2 = global_addr @gint : $*Int32
-  %3 = alloc_stack $InlineArray<2, Int32>
-  %4 = unchecked_addr_cast %3 to $*Int32
+  %3 = alloc_stack $Builtin.FixedArray<2, Int32>
+  %4 = vector_base_addr %3
   %5 = integer_literal $Builtin.Int32, 1
   %6 = struct $Int32 (%5)
   store %6 to [trivial] %4
@@ -511,11 +538,12 @@ sil [global_init_once_fn] [ossa] @no_globalinit_empty_inline_array : $@conventio
 bb0(%0 : $Builtin.RawPointer):
   alloc_global @empty_inline_array
   %2 = global_addr @empty_inline_array : $*InlineArray<0, Int32>
-  %3 = alloc_stack $InlineArray<0, Int32>
-  %4 = unchecked_addr_cast %3 to $*Int32
+  %3 = alloc_stack $Builtin.FixedArray<0, Int32>
+  %4 = vector_base_addr %3
   %18 = load [trivial] %3
+  %19 = struct $InlineArray<0, Int32> (%18)
   dealloc_stack %3
-  store %18 to [trivial] %2
+  store %19 to [trivial] %2
   %21 = tuple ()
   return %21
 }
@@ -529,16 +557,94 @@ sil [global_init_once_fn] [ossa] @no_globalinit_inline_array_empty_elements : $@
 bb0(%0 : $Builtin.RawPointer):
   alloc_global @inline_array_empty_elements
   %2 = global_addr @inline_array_empty_elements : $*InlineArray<3, ()>
-  %3 = alloc_stack $InlineArray<3, ()>
-  %4 = unchecked_addr_cast %3 to $*()
+  %3 = alloc_stack $Builtin.FixedArray<3, ()>
+  %4 = vector_base_addr %3
   %13 = integer_literal $Builtin.Word, 2
   %14 = index_addr %4, %13
   %15 = tuple ()
   store %15 to [trivial] %14
   %18 = load [trivial] %3
+  %19 = struct $InlineArray<3, ()> (%18)
   dealloc_stack %3
-  store %18 to [trivial] %2
+  store %19 to [trivial] %2
+  %21 = tuple ()
+  return %21
+}
+
+sil [global_init_once_fn] [ossa] @globalinit_raw_layout: $@convention(c) (Builtin.RawPointer) -> () {
+bb0(%0 : $Builtin.RawPointer):
+  alloc_global @graw
+  %2 = global_addr @graw : $*Raw
+  %3 = integer_literal $Builtin.Int32, 1
+  %4 = struct $Int32 (%3)
+  %5 = builtin "addressOfRawLayout"<Raw>(%2) : $Builtin.RawPointer
+  %6 = pointer_to_address %5 to $*Int32
+  store %4 to [trivial] %6
+  %21 = tuple ()
+  return %21
+}
+
+sil [global_init_once_fn] [ossa] @no_globalinit_raw_layout_wrong_like_type: $@convention(c) (Builtin.RawPointer) -> () {
+bb0(%0 : $Builtin.RawPointer):
+  alloc_global @graw
+  %2 = global_addr @graw : $*Raw
+  %3 = integer_literal $Builtin.Int16, 1
+  %4 = struct $Int16 (%3)
+  %5 = builtin "addressOfRawLayout"<Raw>(%2) : $Builtin.RawPointer
+  %6 = pointer_to_address %5 to $*Int16
+  store %4 to [trivial] %6
+  %21 = tuple ()
+  return %21
+}
+
+sil [global_init_once_fn] [ossa] @no_globalinit_raw_layout_array: $@convention(c) (Builtin.RawPointer) -> () {
+bb0(%0 : $Builtin.RawPointer):
+  alloc_global @grawArray
+  %2 = global_addr @grawArray : $*RawArray
+  %3 = integer_literal $Builtin.Int32, 1
+  %4 = struct $Int32 (%3)
+  %5 = builtin "addressOfRawLayout"<RawArray>(%2) : $Builtin.RawPointer
+  %6 = pointer_to_address %5 to $*Int32
+  store %4 to [trivial] %6
+  %21 = tuple ()
+  return %21
+}
+
+sil [global_init_once_fn] [ossa] @globalinit_indirect_none: $@convention(c) (Builtin.RawPointer) -> () {
+bb0(%0 : $Builtin.RawPointer):
+  alloc_global @gIndirectNone
+  %2 = global_addr @gIndirectNone : $*Optional<TwoFields>
+  inject_enum_addr %2, #Optional.none!enumelt
   %21 = tuple ()
   return %21
 }
 
+sil [global_init_once_fn] [ossa] @globalinit_indirect_some : $@convention(c) () -> () {
+bb0:
+  alloc_global @gIndirectSome
+  %1 = global_addr @gIndirectSome : $*Optional<TwoFields>
+  %2 = init_enum_data_addr %1, #Optional.some!enumelt
+  %3 = integer_literal $Builtin.Int32, 10
+  %4 = struct $Int32 (%3)
+  %5 = struct_element_addr %2, #TwoFields.b
+  store %4 to [trivial] %5
+  %7 = integer_literal $Builtin.Int32, 11
+  %8 = struct $Int32 (%7)
+  %9 = struct_element_addr %2, #TwoFields.a
+  store %8 to [trivial] %9
+  %10 = tuple ()
+  return %10 : $()
+}
+
+sil [global_init_once_fn] @globalinit_structWithOptionalEnum : $@convention(c) (Builtin.RawPointer) -> () {
+bb0(%0 : $Builtin.RawPointer):
+  alloc_global @structWithOptionalEnum
+  %2 = global_addr @structWithOptionalEnum : $*WithOptionalEnum
+  %3 = struct_element_addr %2, #WithOptionalEnum.e
+  %4 = init_enum_data_addr %3, #Optional.some!enumelt
+  inject_enum_addr %4, #E.a!enumelt
+  inject_enum_addr %3, #Optional.some!enumelt
+  %7 = tuple ()
+  return %7
+}
+
diff --git a/test/SILOptimizer/inline_arrays.swift b/test/SILOptimizer/inline_arrays.swift
new file mode 100644
index 0000000000000..bf7e188a03f82
--- /dev/null
+++ b/test/SILOptimizer/inline_arrays.swift
@@ -0,0 +1,66 @@
+// RUN: %target-swift-frontend  -primary-file %s -O -disable-availability-checking -module-name=test -emit-sil | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-OPT
+
+// REQUIRES: swift_stdlib_no_asserts, optimized_stdlib
+
+// CHECK-LABEL: sil @$s4test0A9Subscriptys5UInt8Vs11InlineArrayVy$255_ADGz_SitF :
+// CHECK-OPT:      [[S:%.*]] = struct_element_addr %0, #InlineArray._storage
+// CHECK-ONONE:    [[ACC:%.*]] = begin_access [read] [static] %0
+// CHECK-ONONE:    [[S:%.*]] = struct_element_addr [[ACC]], #InlineArray._storage
+// CHECK:          [[BA:%.*]] = vector_base_addr [[S]]
+// CHECK:          [[EA:%.*]] = index_addr [stack_protection] [[BA]],
+// CHECK-OPT:      [[E:%.*]] = load [[EA]]
+// CHECK-ONONE:    [[ACC2:%.*]] = begin_access [read] [unsafe] [[EA]]
+// CHECK-ONONE:    [[E:%.*]] = load [[ACC2]]
+// CHECK:          return [[E]]
+// CHECK:       } // end sil function '$s4test0A9Subscriptys5UInt8Vs11InlineArrayVy$255_ADGz_SitF'
+public func testSubscript(_ a: inout InlineArray<256, UInt8>, _ i: Int) -> UInt8 {
+  return a[i]
+}
+
+public final class C {
+  let a: InlineArray<256, UInt8>
+
+  init(_ a: InlineArray<256, UInt8>) {
+    self.a = a
+  }
+
+  // CHECK-LABEL:    sil @$s4test1CC1iACs5UInt8V_tcfc
+  // CHECK-OPT-NOT:    alloc_stack
+  // CHECK:       } // end sil function '$s4test1CC1iACs5UInt8V_tcfc'
+  public init(i: UInt8) {
+    self.a = .init(repeating: i)
+  }
+
+  // CHECK-LABEL: sil @$s4test1CC0A9Subscriptys5UInt8VSiF :
+  // CHECK:          [[CA:%.*]] = ref_element_addr [immutable] %1, #C.a
+  // CHECK:          [[S:%.*]] = struct_element_addr [[CA]], #InlineArray._storage
+  // CHECK:          [[BA:%.*]] = vector_base_addr [[S]]
+  // CHECK:          [[EA:%.*]] = index_addr [stack_protection] [[BA]],
+  // CHECK-OPT:      [[E:%.*]] = load [[EA]]
+  // CHECK-ONONE:    [[ACC2:%.*]] = begin_access [read] [unsafe] [[EA]]
+  // CHECK-ONONE:    [[E:%.*]] = load [[ACC2]]
+  // CHECK:          return [[E]]
+  // CHECK:       } // end sil function '$s4test1CC0A9Subscriptys5UInt8VSiF'
+  public func testSubscript(_ i: Int) -> UInt8 {
+    return a[i]
+  }
+}
+
+public struct S {
+  let a: InlineArray<7000, UInt8>
+
+  // CHECK-LABEL: sil @$s4test1SV0A9Subscriptys5UInt8VSiF :
+  // CHECK:          [[A:%.*]] = struct_element_addr %1, #S.a
+  // CHECK:          [[S:%.*]] = struct_element_addr [[A]], #InlineArray._storage
+  // CHECK:          [[BA:%.*]] = vector_base_addr [[S]]
+  // CHECK:          [[EA:%.*]] = index_addr [stack_protection] [[BA]],
+  // CHECK-OPT:      [[E:%.*]] = load [[EA]]
+  // CHECK-ONONE:    [[ACC2:%.*]] = begin_access [read] [unsafe] [[EA]]
+  // CHECK-ONONE:    [[E:%.*]] = load [[ACC2]]
+  // CHECK:          return [[E]]
+  // CHECK:       } // end sil function '$s4test1SV0A9Subscriptys5UInt8VSiF'
+  public func testSubscript(_ i: Int) -> UInt8 {
+    return a[i]
+  }
+}
+
diff --git a/test/SILOptimizer/inline_devirtualize_specialize.sil b/test/SILOptimizer/inline_devirtualize_specialize.sil
index 4dffa69d6ca97..9d007dedf3715 100644
--- a/test/SILOptimizer/inline_devirtualize_specialize.sil
+++ b/test/SILOptimizer/inline_devirtualize_specialize.sil
@@ -17,7 +17,7 @@ private class C : P {
 }
 
 // CHECK-LABEL: struct_target
-sil [always_inline] @struct_target : $@convention(method) (S) -> Builtin.Int1 {
+sil [heuristic_always_inline] @struct_target : $@convention(method) (S) -> Builtin.Int1 {
 // CHECK: bb0
 bb0(%0 : $S):
   %2 = integer_literal $Builtin.Int1, 0
@@ -25,7 +25,7 @@ bb0(%0 : $S):
 }
 
 // CHECK-LABEL: struct_witness
-sil [always_inline] [thunk] @struct_witness : $@convention(witness_method: P) (@in_guaranteed S) -> Builtin.Int1 {
+sil [heuristic_always_inline] [thunk] @struct_witness : $@convention(witness_method: P) (@in_guaranteed S) -> Builtin.Int1 {
 // CHECK: bb0
 bb0(%0 : $*S):
   // CHECK-NOT: load
@@ -54,14 +54,14 @@ bb0(%0 : $*S):
 }
 
 // CHECK-LABEL: class_target
-sil [always_inline] @class_target : $@convention(method) (@guaranteed C) -> Builtin.Int1 {
+sil [heuristic_always_inline] @class_target : $@convention(method) (@guaranteed C) -> Builtin.Int1 {
 bb0(%0 : $C):
   %1 = integer_literal $Builtin.Int1, -1
   return %1 : $Builtin.Int1
 }
 
 // CHECK-LABEL: class_witness
-sil [always_inline] [thunk] @class_witness : $@convention(witness_method: P) (@in_guaranteed C) -> Builtin.Int1 {
+sil [heuristic_always_inline] [thunk] @class_witness : $@convention(witness_method: P) (@in_guaranteed C) -> Builtin.Int1 {
 // CHECK: bb0
 bb0(%0 : $*C):
   // CHECK-NOT: load
diff --git a/test/SILOptimizer/inline_generics.sil b/test/SILOptimizer/inline_generics.sil
index c49705816a840..f44b1f9480660 100644
--- a/test/SILOptimizer/inline_generics.sil
+++ b/test/SILOptimizer/inline_generics.sil
@@ -66,7 +66,7 @@ bb0(%0 : $T, %1 : $@callee_owned (@owned P) -> Bool):
 } // end sil function 'thunk2'
 
 
-sil [always_inline] @alwaysInlineGenericCallee : $@convention(thin) <T> (@in T) -> @out T {
+sil [heuristic_always_inline] @alwaysInlineGenericCallee : $@convention(thin) <T> (@in T) -> @out T {
 bb0(%0 : $*T, %1 : $*T):
   copy_addr [take] %1 to [init] %0 : $*T
   %4 = tuple ()
@@ -81,7 +81,7 @@ bb0(%0 : $*T, %1 : $*T):
 } // end sil function 'transparentInlineGenericCallee'
 
 
-// Check that [always_inline] and [transparent] functions are inlined even if
+// Check that [heuristic_always_inline] and [transparent] functions are inlined even if
 // inlining of generics is disabled. Regular generic functions should not be
 // inlined.
 // DISABLED-GENERIC-INLINING-CHECK-LABEL: sil @testComplexInliningOfGenerics
@@ -100,7 +100,7 @@ bb0(%0 : $*T, %1 : $*T):
 sil @testComplexInliningOfGenerics : $@convention(thin) <T> (@in T) -> @out T {
 bb0(%0 : $*T, %1 : $*T):
 
-  // Call an [always_inline] function.
+  // Call an [heuristic_always_inline] function.
   %3 = function_ref @alwaysInlineGenericCallee : $@convention(thin) <τ_0_0> (@in τ_0_0) -> @out τ_0_0
   %4 = alloc_stack $T
   copy_addr %1 to [init] %4 : $*T
@@ -169,7 +169,7 @@ bb0(%0 : $MyNumber):
 
 sil @dootherstuff : $@convention(thin) <τ_0_0 where τ_0_0 : OtherProto> (@in_guaranteed τ_0_0) -> ()
 
-sil shared [signature_optimized_thunk] [always_inline] @doStuff : $@convention(thin) <τ_0_0 where τ_0_0 : OtherProto> (@in_guaranteed τ_0_0) -> () {
+sil shared [signature_optimized_thunk] [heuristic_always_inline] @doStuff : $@convention(thin) <τ_0_0 where τ_0_0 : OtherProto> (@in_guaranteed τ_0_0) -> () {
 bb0(%0 : $*τ_0_0):
   %2 = function_ref @dootherstuff : $@convention(thin) <τ_0_0 where τ_0_0 : OtherProto> (@in_guaranteed τ_0_0) -> ()
   %3 = apply %2<τ_0_0>(%0) : $@convention(thin) <τ_0_0 where τ_0_0 : OtherProto> (@in_guaranteed τ_0_0) -> ()
diff --git a/test/SILOptimizer/inline_heuristics.sil b/test/SILOptimizer/inline_heuristics.sil
index 50ebfe459fd5d..53ca63559eb24 100644
--- a/test/SILOptimizer/inline_heuristics.sil
+++ b/test/SILOptimizer/inline_heuristics.sil
@@ -30,22 +30,27 @@ enum E {
 	case B((Int32) -> Int32)
 }
 
+class C {
+  init()
+}
 
 // CHECK-LABEL: sil @testDirectClosure
 // CHECK: [[C:%[0-9]+]] = thin_to_thick_function
-// CHECK: apply [[C]](
+// CHECK: [[MD:%[0-9]+]] = mark_dependence [[C]]
+// CHECK: apply [[MD]](
 // CHECK: return
 
 // CHECK-LOG-LABEL: Inline into caller: testDirectClosure
 // CHECK-LOG-NEXT: decision {{.*}}, b=70,
 
-sil @testDirectClosure : $@convention(thin) () -> Int32 {
-bb0:
+sil @testDirectClosure : $@convention(thin) (@guaranteed C) -> Int32 {
+bb0(%c : $C):
   %0 = function_ref @takeDirectClosure : $@convention(thin) (@owned @callee_guaranteed (Int32) -> Int32) -> Int32
   %1 = function_ref @closure : $@convention(thin) (Int32) -> Int32
   %2 = thin_to_thick_function %1 : $@convention(thin) (Int32) -> Int32 to $@callee_guaranteed (Int32) -> Int32
-  %3 = apply %0(%2) : $@convention(thin) (@owned @callee_guaranteed (Int32) -> Int32) -> Int32
-  return %3 : $Int32
+  %3 = mark_dependence %2 on %c
+  %4 = apply %0(%3) : $@convention(thin) (@owned @callee_guaranteed (Int32) -> Int32) -> Int32
+  return %4 : $Int32
 }
 
 sil @takeDirectClosure : $@convention(thin) (@owned @callee_guaranteed (Int32) -> Int32) -> Int32 {
diff --git a/test/SILOptimizer/inline_lifetime.sil b/test/SILOptimizer/inline_lifetime.sil
index 3c3a982096272..352172ef81fc2 100644
--- a/test/SILOptimizer/inline_lifetime.sil
+++ b/test/SILOptimizer/inline_lifetime.sil
@@ -68,166 +68,166 @@ struct S {}
 
 // declarations
 
-sil [ossa] [always_inline] @callee_owned : $@convention(thin) (@owned C) -> () {
+sil [ossa] [heuristic_always_inline] @callee_owned : $@convention(thin) (@owned C) -> () {
 entry(%instance : @owned $C):
     destroy_value %instance : $C
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_owned_eager_move : $@convention(thin) (@owned C) -> () {
+sil [ossa] [heuristic_always_inline] @callee_owned_eager_move : $@convention(thin) (@owned C) -> () {
 entry(%instance : @_eagerMove @owned $C):
     destroy_value %instance : $C
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_owned_eager_move__type_annotation : $@convention(thin) (@owned EagerC) -> () {
+sil [ossa] [heuristic_always_inline] @callee_owned_eager_move__type_annotation : $@convention(thin) (@owned EagerC) -> () {
 entry(%instance : @owned $EagerC):
     destroy_value %instance : $EagerC
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_owned_eager_move__type_inferred_d1_s1 : $@convention(thin) (@owned InferredEagerD1S1) -> () {
+sil [ossa] [heuristic_always_inline] @callee_owned_eager_move__type_inferred_d1_s1 : $@convention(thin) (@owned InferredEagerD1S1) -> () {
 entry(%instance : @owned $InferredEagerD1S1):
     destroy_value %instance : $InferredEagerD1S1
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_owned_eager_move__type_inferred_d1_s2 : $@convention(thin) (@owned InferredEagerD1S2) -> () {
+sil [ossa] [heuristic_always_inline] @callee_owned_eager_move__type_inferred_d1_s2 : $@convention(thin) (@owned InferredEagerD1S2) -> () {
 entry(%instance : @owned $InferredEagerD1S2):
     destroy_value %instance : $InferredEagerD1S2
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_owned_eager_move__type_inferred_d1_s3 : $@convention(thin) (@owned InferredEagerD1S3) -> () {
+sil [ossa] [heuristic_always_inline] @callee_owned_eager_move__type_inferred_d1_s3 : $@convention(thin) (@owned InferredEagerD1S3) -> () {
 entry(%instance : @owned $InferredEagerD1S3):
     destroy_value %instance : $InferredEagerD1S3
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_owned_eager_move__type_inferred_d1_s4 : $@convention(thin) (@owned InferredEagerD1S4) -> () {
+sil [ossa] [heuristic_always_inline] @callee_owned_eager_move__type_inferred_d1_s4 : $@convention(thin) (@owned InferredEagerD1S4) -> () {
 entry(%instance : @owned $InferredEagerD1S4):
     destroy_value %instance : $InferredEagerD1S4
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_owned_eager_move__type_inferred_d2_s1 : $@convention(thin) (@owned InferredEagerD2S1) -> () {
+sil [ossa] [heuristic_always_inline] @callee_owned_eager_move__type_inferred_d2_s1 : $@convention(thin) (@owned InferredEagerD2S1) -> () {
 entry(%instance : @owned $InferredEagerD2S1):
     destroy_value %instance : $InferredEagerD2S1
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_owned_lexical : $@convention(thin) (@owned InferredEagerD2S1) -> () {
+sil [ossa] [heuristic_always_inline] @callee_owned_lexical : $@convention(thin) (@owned InferredEagerD2S1) -> () {
 entry(%instance : @_lexical @owned $InferredEagerD2S1):
     destroy_value %instance : $InferredEagerD2S1
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed : $@convention(thin) (@guaranteed C) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed : $@convention(thin) (@guaranteed C) -> () {
 entry(%instance : @guaranteed $C):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_eager_move : $@convention(thin) (@guaranteed C) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_eager_move : $@convention(thin) (@guaranteed C) -> () {
 entry(%instance : @_eagerMove @guaranteed $C):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_eager_move__type_annotation : $@convention(thin) (@guaranteed EagerC) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_eager_move__type_annotation : $@convention(thin) (@guaranteed EagerC) -> () {
 entry(%instance : @guaranteed $EagerC):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_eager_move__type_inferred_d1_s1 : $@convention(thin) (@guaranteed InferredEagerD1S1) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_eager_move__type_inferred_d1_s1 : $@convention(thin) (@guaranteed InferredEagerD1S1) -> () {
 entry(%instance : @guaranteed $InferredEagerD1S1):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_eager_move__type_inferred_d1_s2 : $@convention(thin) (@guaranteed InferredEagerD1S2) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_eager_move__type_inferred_d1_s2 : $@convention(thin) (@guaranteed InferredEagerD1S2) -> () {
 entry(%instance : @guaranteed $InferredEagerD1S2):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_eager_move__type_inferred_d1_s3 : $@convention(thin) (@guaranteed InferredEagerD1S3) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_eager_move__type_inferred_d1_s3 : $@convention(thin) (@guaranteed InferredEagerD1S3) -> () {
 entry(%instance : @guaranteed $InferredEagerD1S3):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_eager_move__type_inferred_d1_s4 : $@convention(thin) (@guaranteed InferredEagerD1S4) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_eager_move__type_inferred_d1_s4 : $@convention(thin) (@guaranteed InferredEagerD1S4) -> () {
 entry(%instance : @guaranteed $InferredEagerD1S4):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_eager_move__type_inferred_d2_s1 : $@convention(thin) (@guaranteed InferredEagerD2S1) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_eager_move__type_inferred_d2_s1 : $@convention(thin) (@guaranteed InferredEagerD2S1) -> () {
 entry(%instance : @guaranteed $InferredEagerD2S1):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_lexical : $@convention(thin) (@guaranteed InferredEagerD2S1) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_lexical : $@convention(thin) (@guaranteed InferredEagerD2S1) -> () {
 entry(%instance : @_lexical @guaranteed $InferredEagerD2S1):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_lexical__type_annotation : $@convention(thin) (@guaranteed LexicalS) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_lexical__type_annotation : $@convention(thin) (@guaranteed LexicalS) -> () {
 entry(%instance : @guaranteed $LexicalS):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_lexical__type_inferred_d1_s1 : $@convention(thin) (@guaranteed InferredLexicalD1S1) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_lexical__type_inferred_d1_s1 : $@convention(thin) (@guaranteed InferredLexicalD1S1) -> () {
 entry(%instance : @guaranteed $InferredLexicalD1S1):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_lexical__type_inferred_d1_s2 : $@convention(thin) (@guaranteed InferredLexicalD1S2) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_lexical__type_inferred_d1_s2 : $@convention(thin) (@guaranteed InferredLexicalD1S2) -> () {
 entry(%instance : @guaranteed $InferredLexicalD1S2):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_lexical__type_inferred_d1_s3 : $@convention(thin) (@guaranteed InferredLexicalD1S3) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_lexical__type_inferred_d1_s3 : $@convention(thin) (@guaranteed InferredLexicalD1S3) -> () {
 entry(%instance : @guaranteed $InferredLexicalD1S3):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_guaranteed_lexical__type_inferred_d1_s4 : $@convention(thin) (@guaranteed InferredLexicalD1S4) -> () {
+sil [ossa] [heuristic_always_inline] @callee_guaranteed_lexical__type_inferred_d1_s4 : $@convention(thin) (@guaranteed InferredLexicalD1S4) -> () {
 entry(%instance : @guaranteed $InferredLexicalD1S4):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_trivial : $@convention(thin) (S) -> () {
+sil [ossa] [heuristic_always_inline] @callee_trivial : $@convention(thin) (S) -> () {
 entry(%instance : $S):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [ossa] [always_inline] @callee_in : $@convention(thin) (@in S) -> () {
+sil [ossa] [heuristic_always_inline] @callee_in : $@convention(thin) (@in S) -> () {
 entry(%instance : $*S):
     %retval = tuple ()
     return %retval : $()
 }
 
-sil [always_inline] [ossa] @callee_inguaranteed : $@convention(thin) <T> (@in_guaranteed T) -> () {
+sil [heuristic_always_inline] [ossa] @callee_inguaranteed : $@convention(thin) <T> (@in_guaranteed T) -> () {
 entry(%arg : $*T):
   %retval = tuple ()
   return %retval : $()
@@ -584,7 +584,7 @@ bb0:
 
 // declarations
 
-sil [ossa] [always_inline] @callee_coro_owned : $@yield_once @convention(thin) (@owned C) -> @yields @inout C {
+sil [ossa] [heuristic_always_inline] @callee_coro_owned : $@yield_once @convention(thin) (@owned C) -> @yields @inout C {
 bb0(%instance : @owned $C):
   %addr = alloc_stack $C
   store %instance to [init] %addr : $*C
@@ -600,7 +600,7 @@ bb2:
   unwind
 }
 
-sil [ossa] [always_inline] @callee_coro_guaranteed : $@yield_once @convention(thin) (@guaranteed C) -> @yields @inout C {
+sil [ossa] [heuristic_always_inline] @callee_coro_guaranteed : $@yield_once @convention(thin) (@guaranteed C) -> @yields @inout C {
 bb0(%instance : @guaranteed $C):
   %copy = copy_value %instance : $C
   %addr = alloc_stack $C
@@ -617,7 +617,7 @@ bb2:
   unwind
 }
 
-sil hidden [ossa] [always_inline] @callee_coro_trivial : $@yield_once @convention(thin) (S) -> @yields @inout S {
+sil hidden [ossa] [heuristic_always_inline] @callee_coro_trivial : $@yield_once @convention(thin) (S) -> @yields @inout S {
 bb0(%instance : $S):
   %addr = alloc_stack $S
   store %instance to [trivial] %addr : $*S
@@ -631,7 +631,7 @@ bb2:
   unwind
 }
 
-sil hidden [ossa] [always_inline] @callee_coro_in : $@yield_once @convention(thin) (@in S) -> @yields @inout S {
+sil hidden [ossa] [heuristic_always_inline] @callee_coro_in : $@yield_once @convention(thin) (@in S) -> @yields @inout S {
 bb0(%instance : $*S):
   yield %instance : $*S, resume bb1, unwind bb2
 bb1:
@@ -641,7 +641,7 @@ bb2:
   unwind
 }
 
-sil hidden [ossa] [always_inline] @callee_coro_inguaranteed : $@yield_once @convention(thin) <T> (@in_guaranteed T) -> @yields @inout T {
+sil hidden [ossa] [heuristic_always_inline] @callee_coro_inguaranteed : $@yield_once @convention(thin) <T> (@in_guaranteed T) -> @yields @inout T {
 bb0(%instance : $*T):
   %addr = alloc_stack $T
   copy_addr %instance to [init] %addr : $*T
@@ -781,7 +781,7 @@ bb0(%instance : $*T):
 
 // declarations
 
-sil [ossa] [always_inline] @callee_error_owned : $@convention(thin) (@owned C) -> @error Error {
+sil [ossa] [heuristic_always_inline] @callee_error_owned : $@convention(thin) (@owned C) -> @error Error {
 bb0(%instance : @owned $C):
   cond_br undef, bb1, bb2
 bb1:
@@ -793,7 +793,7 @@ bb2:
   return %18 : $()
 }
 
-sil [ossa] [always_inline] @callee_error_guaranteed : $@convention(thin) (@guaranteed C) -> @error Error {
+sil [ossa] [heuristic_always_inline] @callee_error_guaranteed : $@convention(thin) (@guaranteed C) -> @error Error {
 bb0(%0 : @guaranteed $C):
   cond_br undef, bb1, bb2
 bb1:
diff --git a/test/SILOptimizer/inline_tryApply.sil b/test/SILOptimizer/inline_tryApply.sil
index f77c3735daae4..6bce1d9276fe5 100644
--- a/test/SILOptimizer/inline_tryApply.sil
+++ b/test/SILOptimizer/inline_tryApply.sil
@@ -23,11 +23,11 @@ bb2(%5 : $Error):                             // Preds: bb0
   throw %5 : $Error                           // id: %6
 }
 
-//CHECK-LABEL: sil [always_inline] @callee_function
+//CHECK-LABEL: sil [heuristic_always_inline] @callee_function
 //CHECK: return
 
 // main.inner () throws -> ()
-sil [always_inline] @callee_function : $@convention(thin) () -> @error Error {
+sil [heuristic_always_inline] @callee_function : $@convention(thin) () -> @error Error {
 bb0:
   %0 = tuple ()                                   // user: %1
   return %0 : $()                                 // id: %1
diff --git a/test/SILOptimizer/inlinealways_inliner.sil b/test/SILOptimizer/inlinealways_inliner.sil
index 770d6a8ae45af..1721984bb4cbf 100644
--- a/test/SILOptimizer/inlinealways_inliner.sil
+++ b/test/SILOptimizer/inlinealways_inliner.sil
@@ -4,7 +4,7 @@ sil @doSomething1 : $@convention(thin) () -> ()
 sil @doSomething2 : $@convention(thin) () -> ()
 sil @doSomething3 : $@convention(thin) () -> ()
 
-sil [ossa] [always_inline] @do_inline_this : $@convention(thin) () -> () {
+sil [ossa] [heuristic_always_inline] @do_inline_this : $@convention(thin) () -> () {
 bb0:
   %d1 = function_ref @doSomething1 : $@convention(thin) () -> ()
   apply %d1() : $@convention(thin) () -> ()
diff --git a/test/SILOptimizer/inlinearray_bounds_check_tests.swift b/test/SILOptimizer/inlinearray_bounds_check_tests.swift
index 49e75f2340379..1e23e65bf4485 100644
--- a/test/SILOptimizer/inlinearray_bounds_check_tests.swift
+++ b/test/SILOptimizer/inlinearray_bounds_check_tests.swift
@@ -1,8 +1,8 @@
 // RUN: %target-swift-frontend %s -emit-sil -O \
-// RUN:   -disable-availability-checking | %FileCheck %s --check-prefix=CHECK-SIL 
+// RUN:   -disable-availability-checking | %FileCheck %s --check-prefix=CHECK-SIL
 
 // RUN: %target-swift-frontend %s -emit-ir -O \
-// RUN:   -disable-availability-checking | %FileCheck %s  --check-prefix=CHECK-IR 
+// RUN:   -disable-availability-checking | %FileCheck %s  --check-prefix=CHECK-IR
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_stdlib_no_asserts, optimized_stdlib
@@ -131,7 +131,7 @@ public func inlinearray_sum_iterate_to_deducible_count2_wo_trap<let N: Int>(_ v:
 
 // Bounds check should be eliminated
 
-// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A42_sum_iterate_to_deducible_count2_with_trapySis11InlineArrayVyxSiG_SitSiRVzlF : 
+// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A42_sum_iterate_to_deducible_count2_with_trapySis11InlineArrayVyxSiG_SitSiRVzlF :
 // CHECK-SIL: bb3
 // CHECK-SIL-NOT: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_br
@@ -147,7 +147,7 @@ public func inlinearray_sum_iterate_to_deducible_count2_with_trap<let N: Int>(_
 
 // Bounds check should be eliminated
 
-// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A29_iterate_over_indices_wo_trapySis11InlineArrayVyxSiGSiRVzlF : 
+// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A29_iterate_over_indices_wo_trapySis11InlineArrayVyxSiGSiRVzlF :
 // CHECK-SIL: bb3
 // CHECK-SIL-NOT: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_br
@@ -166,7 +166,7 @@ public func inlinearray_iterate_over_indices_wo_trap<let N: Int>(_ v: InlineArra
 // Bounds check should be eliminated
 // Induction variable optimization eliminates the bounds check in SIL
 
-// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A31_iterate_over_indices_with_trapySis11InlineArrayVyxSiGSiRVzlF : 
+// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A31_iterate_over_indices_with_trapySis11InlineArrayVyxSiGSiRVzlF :
 // CHECK-SIL: bb3
 // CHECK-SIL-NOT: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_br
@@ -181,7 +181,7 @@ public func inlinearray_iterate_over_indices_with_trap<let N: Int>(_ v: InlineAr
 
 // Eliminate duplicate bounds check
 
-// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A17_element_equalityySbs11InlineArrayVyxSiG_SitSiRVzlF : 
+// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A17_element_equalityySbs11InlineArrayVyxSiG_SitSiRVzlF :
 // CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL-NOT: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL-LABEL: } // end sil function '$s30inlinearray_bounds_check_tests0A17_element_equalityySbs11InlineArrayVyxSiG_SitSiRVzlF'
@@ -201,7 +201,7 @@ public func inlinearray_element_sum<let N: Int>(_ v: InlineArray<N, Int>, _ i: I
 
 // Bounds check should be eliminated
 
-// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A7_searchySiSgs11InlineArrayVyq_xG_xtSiRV_SQRzr0_lF : 
+// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A7_searchySiSgs11InlineArrayVyq_xG_xtSiRV_SQRzr0_lF :
 // CHECK-SIL: bb3:
 // CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
@@ -218,7 +218,7 @@ public func inlinearray_search<T : Equatable, let N: Int>(_ v: InlineArray<N, T>
 
 // Bounds check should be eliminated
 
-// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A11_search_splySiSgs11InlineArrayVyxSiG_SitSiRVzlF : 
+// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A11_search_splySiSgs11InlineArrayVyxSiG_SitSiRVzlF :
 // CHECK-SIL: bb3:
 // CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
@@ -235,7 +235,7 @@ public func inlinearray_search_spl<let N: Int>(_ v: InlineArray<N, Int>, _ elem:
 
 // Bounds check should be eliminated
 
-// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A18_binary_search_splySiSgs11InlineArrayVyxSiG_SitSiRVzlF : 
+// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A18_binary_search_splySiSgs11InlineArrayVyxSiG_SitSiRVzlF :
 // CHECK-SIL: bb2
 // CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_br
@@ -262,7 +262,7 @@ public func inlinearray_binary_search_spl<let N: Int>(_ v: InlineArray<N, Int>,
 // This prevents LoopRotate which prevent bounds checks opts since it depends on induction variable analysis which doesn't work on unrotated loops.
 // CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A35_sum_iterate_to_count_with_trap_splySis11InlineArrayVy$63_SiGF :
 // CHECK-SIL: bb2
-// CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
+// CHECK-NOT-SIL: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_br
 // CHECK-SIL-LABEL: } // end sil function '$s30inlinearray_bounds_check_tests0A35_sum_iterate_to_count_with_trap_splySis11InlineArrayVy$63_SiGF'
 public func inlinearray_sum_iterate_to_count_with_trap_spl(_ v: InlineArray<64, Int>) -> Int {
@@ -274,7 +274,7 @@ public func inlinearray_sum_iterate_to_count_with_trap_spl(_ v: InlineArray<64,
 }
 
 // InlineArray is copied into a temporary within the loop in the "specialized" version
-// This prevents LoopRotate which prevent bounds checks opts since it depends on induction variable analysis which doesn't work on unrotated loops. 
+// This prevents LoopRotate which prevent bounds checks opts since it depends on induction variable analysis which doesn't work on unrotated loops.
 // CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A37_sum_iterate_to_unknown_with_trap_splySis11InlineArrayVy$63_SiG_SitF :
 // CHECK-SIL: bb2
 // CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
@@ -290,7 +290,7 @@ public func inlinearray_sum_iterate_to_unknown_with_trap_spl(_ v: InlineArray<64
 
 // Current codegen for this in SIL is very poor
 // First a temp is created and the elements are stored to it, then they get loaded from the temp to be stored in the let which is then loaded again to get the sum
-// However, LLVM can constant fold everything 
+// However, LLVM can constant fold everything
 public func local_inlinearray_sum_iterate_to_count_with_trap_spl() -> Int {
   var sum = 0
   let v : InlineArray = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16]
@@ -302,7 +302,7 @@ public func local_inlinearray_sum_iterate_to_count_with_trap_spl() -> Int {
 
 // Current codegen for this in SIL is very poor
 // First a temp is created and the elements are stored to it, then they get loaded from the temp to be stored in the let which is then loaded again to get the sum
-// LLVM cannot constant fold, it memsets, memcopies and then loops over to sum  
+// LLVM cannot constant fold, it memsets, memcopies and then loops over to sum
 public func local_inlinearray_repeating_init_sum_iterate_to_count_trap_spl() -> Int {
   var sum = 0
   let v = InlineArray<64, Int>(repeating: 64)
@@ -324,9 +324,9 @@ public func inlinearray_inc_by_one<let N: Int>(_ v: inout InlineArray<N, Int>, _
   }
 }
 
-// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A15_inc_by_one_splyys11InlineArrayVy$63_SiGz_SitF : 
+// CHECK-SIL-LABEL: sil @$s30inlinearray_bounds_check_tests0A15_inc_by_one_splyys11InlineArrayVy$63_SiGz_SitF :
 // CHECK-SIL: bb2
-// CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
+// CHECK-NOT-SIL: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_br
 // CHECK-SIL-LABEL: } // end sil function '$s30inlinearray_bounds_check_tests0A15_inc_by_one_splyys11InlineArrayVy$63_SiGz_SitF'
 public func inlinearray_inc_by_one_spl(_ v: inout InlineArray<64, Int>, _ n: Int) {
diff --git a/test/SILOptimizer/instruction_deleter.sil b/test/SILOptimizer/instruction_deleter.sil
index bb50d8c2f2627..91ea283b07967 100644
--- a/test/SILOptimizer/instruction_deleter.sil
+++ b/test/SILOptimizer/instruction_deleter.sil
@@ -57,3 +57,18 @@ sil [ossa] @doDeleteLoadTake : $() -> () {
   %retval = tuple ()
   return %retval : $()
 }
+
+// CHECK-LABEL: begin running test {{.*}} on trackEndBorrow
+// CHECK: Tracking   end_borrow undef : $C
+// CHECK: sil [ossa] @trackEndBorrow : $@convention(thin) () -> () {
+// CHECK: bb0:
+// CHECK-NOT: end_borrow
+// CHECK-LABEL: } // end sil function 'trackEndBorrow'
+// CHECK-LABEL: end running test {{.*}} on trackEndBorrow
+sil [ossa] @trackEndBorrow : $() -> () {
+bb0:
+  specify_test "deleter_track_if_dead @instruction"
+  end_borrow undef : $C
+  %retval = tuple ()
+  return %retval : $()
+}
diff --git a/test/SILOptimizer/isolated_conformances.swift b/test/SILOptimizer/isolated_conformances.swift
new file mode 100644
index 0000000000000..2c5e66d0942e7
--- /dev/null
+++ b/test/SILOptimizer/isolated_conformances.swift
@@ -0,0 +1,59 @@
+// RUN: %empty-directory(%t) 
+// RUN: %target-build-swift -parse-as-library -O %s -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s --check-prefix=CHECK-OUTPUT
+
+// RUN: %target-build-swift -parse-as-library -O %s -Xllvm -sil-disable-pass=function-signature-opts -emit-sil | %FileCheck %s
+
+// REQUIRES: concurrency
+// REQUIRES: executable_test
+// REQUIRES: concurrency_runtime
+// REQUIRES: OS=macosx || OS=linux-gnu
+
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: back_deploy_concurrency
+
+protocol P {
+  func f() -> Int
+}
+
+struct X: @MainActor P {
+  func f() -> Int { 17 }
+}
+
+// CHECK-LABEL: sil hidden [noinline] @$s21isolated_conformances12castAnywhereySiSgAA1XVF :
+// CHECK:         checked_cast_addr_br take_always X in %{{[0-9]+}} to any P in %{{[0-9]+}}, bb1, bb2
+// CHECK:       } // end sil function '$s21isolated_conformances12castAnywhereySiSgAA1XVF'
+@inline(never)
+nonisolated func castAnywhere(_ value: X) -> Int? {
+  if let value = value as? P {
+    return value.f()
+  }
+  return nil
+}
+
+// CHECK-LABEL: sil hidden [noinline] @$s21isolated_conformances15castOnMainActorySiSgAA1XVF :
+// CHECK:         [[L:%.*]] = integer_literal {{.*}} 17
+// CHECK:         [[I:%.*]] = struct $Int ([[L]])
+// CHECK:         [[O:%.*]] = enum $Optional<Int>, #Optional.some!enumelt, [[I]]
+// CHECK:         return [[O]]
+// CHECK:       } // end sil function '$s21isolated_conformances15castOnMainActorySiSgAA1XVF'
+@MainActor
+@inline(never)
+func castOnMainActor(_ value: X) -> Int? {
+  if let value = value as? P {
+    return value.f()
+  }
+  return nil
+}
+
+
+@main
+struct Main {
+  static func main() async {
+    await Task.detached {
+      // CHECK-OUTPUT: nil
+      print(castAnywhere(X()))
+    }.value
+  }
+}
diff --git a/test/SILOptimizer/jumpthreadtest.swift b/test/SILOptimizer/jumpthreadtest.swift
index e0adcd7a7d78e..5c82d89e9fea0 100644
--- a/test/SILOptimizer/jumpthreadtest.swift
+++ b/test/SILOptimizer/jumpthreadtest.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -O -parse-as-library -emit-sil -enable-ossa-modules %s | %FileCheck %s
+// RUN: %target-swift-frontend -O -parse-as-library -emit-sil %s | %FileCheck %s
 // REQUIRES: PTRSIZE=32,swift_stdlib_asserts
 
 import Swift
diff --git a/test/SILOptimizer/keypath_opt_crash.swift b/test/SILOptimizer/keypath_opt_crash.swift
index 6117c41ab7489..a65f56cfc5bea 100644
--- a/test/SILOptimizer/keypath_opt_crash.swift
+++ b/test/SILOptimizer/keypath_opt_crash.swift
@@ -10,7 +10,7 @@ import Foundation
 public struct S {
   private let x: NSXPCConnection
 
-  subscript<T>(dynamicMember property: ReferenceWritableKeyPath<NSXPCConnection, T>) -> T {
+  public subscript<T>(dynamicMember property: ReferenceWritableKeyPath<NSXPCConnection, T>) -> T {
     get {
       x[keyPath: property]
     }
diff --git a/test/SILOptimizer/let-property-lowering.sil b/test/SILOptimizer/let-property-lowering.sil
index f0f37107ead50..01fb24cc872f8 100644
--- a/test/SILOptimizer/let-property-lowering.sil
+++ b/test/SILOptimizer/let-property-lowering.sil
@@ -311,3 +311,34 @@ bb1(%3a : @reborrow $C):
   return %2 : $C
 }
 
+
+// CHECK-LABEL: sil [ossa] @test_no_phis :
+// CHECK:         %3 = end_init_let_ref %2
+// CHECK:         return %3
+// CHECK:       } // end sil function 'test_no_phis'
+sil [ossa] @test_no_phis : $@convention(thin) (Int, @owned C) -> @owned C {
+bb0(%0 : $Int, %1 : @owned $C):
+  %2 = mark_uninitialized [rootself] %1
+  %3 = begin_borrow %2
+  cond_br undef, bb1, bb2
+bb1:
+  br bb7
+bb2:
+  cond_br undef, bb3, bb8
+bb3:
+  cond_br undef, bb4, bb5
+bb4:
+  br bb7
+bb5:
+  br bb6
+bb6:
+  end_borrow %3
+  return %2
+bb7:
+  br bb6
+bb8:
+  end_borrow %3
+  destroy_value [dead_end] %2
+  unreachable
+}
+
diff --git a/test/SILOptimizer/licm.sil b/test/SILOptimizer/licm.sil
index 4955174801c91..4c1548d4043b9 100644
--- a/test/SILOptimizer/licm.sil
+++ b/test/SILOptimizer/licm.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enforce-exclusivity=none -enable-sil-verify-all %s -licm | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enforce-exclusivity=none -enable-sil-verify-all %s -loop-invariant-code-motion | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 
@@ -18,6 +18,21 @@ struct NonCopyable : ~Copyable {
   var x: Int
 }
 
+struct S {
+  var i: Int
+  var s: String
+}
+
+struct S2 {
+  var i: Int
+  var s1: String
+  var s2: String
+}
+
+struct Pair  {
+  var t: (a: Int, b: Int)
+}
+
 // globalArray
 sil_global @globalArray : $Storage
 
@@ -173,13 +188,14 @@ bb4:
 sil [_semantics "array.get_count"] @getCount : $@convention(method) (@guaranteed Array<Int>) -> Int
 sil @user : $@convention(thin) (Int) -> ()
 
-// CHECK-LABEL:   sil @dont_hoist_get_count_on_low_level_sil
-// CHECK:         {{^}}bb1:
+// CHECK-LABEL:   sil @hoist_get_count_on_low_level_sil
+// CHECK:         {{^}}bb0(%0 : $Array<Int>):
 // CHECK:           apply
+// CHECK:         {{^}}bb1:
 // CHECK:           apply
 // CHECK:         {{^}}bb2:
 // CHECK:           return
-sil @dont_hoist_get_count_on_low_level_sil : $@convention(thin) (@guaranteed Array<Int>) -> () {
+sil @hoist_get_count_on_low_level_sil : $@convention(thin) (@guaranteed Array<Int>) -> () {
 bb0(%0 : $Array<Int>):
   br bb1
 
@@ -576,6 +592,45 @@ bb6:
   return %12 : $()
 }
 
+// CHECK-LABEL: sil @dont_sink_store_with_nonmaterializable_load_projection
+// CHECK:       alloc_stack
+// CHECK-NOT:   store
+// CHECK: bb1(%8 : $Builtin.Int64, %9 : $Builtin.Int64):
+// CHECK:       store
+// CHECK:       [[INDEXADDR:%.*]] = index_addr
+// CHECK:       load [[INDEXADDR]]
+// CHECK: bb3:
+// CHECK-NOT:   store
+// CHECK:       dealloc_stack
+// CHECK: } // end sil function 'dont_sink_store_with_nonmaterializable_load_projection'
+sil @dont_sink_store_with_nonmaterializable_load_projection : $@convention(method) (InlineArray<3, Int>) -> () {
+bb0(%0 : $InlineArray<3, Int>):
+  %1 = integer_literal $Builtin.Int64, 0
+  %2 = integer_literal $Builtin.Int64, 1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = struct_extract %0, #InlineArray._storage
+  %5 = alloc_stack $Builtin.FixedArray<3, Int>
+  %6 = vector_base_addr %5
+  br bb1(%1, %1)
+
+bb1(%8 : $Builtin.Int64, %9 : $Builtin.Int64):
+  %10 = builtin "sadd_with_overflow_Int64"(%8, %2, %3) : $(Builtin.Int64, Builtin.Int1)
+  %11 = tuple_extract %10, 0
+  store %4 to %5
+  %13 = builtin "truncOrBitCast_Int64_Word"(%9) : $Builtin.Word
+  %14 = index_addr [stack_protection] %6, %13
+  %15 = load %14
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1(%1, %1)
+
+bb3:
+  dealloc_stack %5
+  %18 = tuple ()
+  return %18
+}
+
 // CHECK-LABEL: sil @hoist_loads_and_stores_multiple_exits
 // CHECK:   [[V1:%[0-9]+]] = load %0
 // CHECK:   br bb1([[V1]] : $Int32)
@@ -934,12 +989,9 @@ bb5:
   return %99 : $()
 }
 
-// Test load splitting with a loop-invariant stored value. The loop
+// Test load splitting with a loop-invariant. The loop
 // will be empty after combined load/store hoisting/sinking.
 //
-// TODO: sink a struct_extract (or other non-side-effect instructions)
-//        with no uses in the loop.
-//
 // CHECK-LABEL: sil shared @testLoadSplit : $@convention(method) (Int64, Builtin.RawPointer) -> (Index, Int64, Builtin.Int64) {
 // CHECK:         [[PRELOAD:%.*]] = load %{{.*}} : $*Int64
 // CHECK:         [[STOREDVAL:%.*]] = struct_extract %0 : $Int64, #Int64._value
@@ -975,12 +1027,12 @@ bb2:
 bb3:
   %result = tuple (%val1 : $Index, %val2 : $Int64, %val3 : $Builtin.Int64)
   return %result : $(Index, Int64, Builtin.Int64)
-}
+} // end sil function 'testLoadSplit'
 
 // Test load splitting with a loop-varying stored value.
 // CHECK-LABEL: sil shared @testLoadSplitPhi : $@convention(method) (Int64, Builtin.RawPointer) -> (Index, Int64, Builtin.Int64) {
 // CHECK:        [[PRELOAD:%.*]] = load %{{.*}} : $*Int64
-// CHECK:        br bb1(%4 : $Int64)
+// CHECK:        br bb1(%{{.*}} : $Int64)
 // CHECK:      bb1([[PHI:%.*]] : $Int64):
 // CHECK-NEXT:   [[OUTERVAL:%.*]] = struct $Index ([[PHI]] : $Int64)
 // CHECK-NEXT:   [[EXTRACT:%.*]] = struct_extract [[PHI]] : $Int64, #Int64._value
@@ -1021,7 +1073,7 @@ bb2:
 bb3:
   %result = tuple (%outerVal : $Index, %middleVal : $Int64, %innerVal : $Builtin.Int64)
   return %result : $(Index, Int64, Builtin.Int64)
-}
+} // end sil function 'testLoadSplitPhi'
 
 struct State {
   @_hasStorage var valueSet: (Int64, Int64, Int64) { get set }
@@ -1036,11 +1088,12 @@ struct State {
 // CHECK:   bb0(%0 : $Builtin.RawPointer):
 // CHECK:     [[HOISTADR:%.*]] = tuple_element_addr %{{.*}} : $*(Int64, Int64, Int64), 0
 // ...Preload stored element #1
+// CHECK:     tuple_element_addr
 // CHECK:     [[PRELOADADR:%.*]] = tuple_element_addr %{{.*}} : $*(Int64, Int64, Int64), 1
 // CHECK:     [[PRELOAD:%.*]] = load [[PRELOADADR]] : $*Int64
 // ...Split element 0
-// CHECK:     [[SPLIT0:%.*]] = tuple_element_addr %{{.*}} : $*(Int64, Int64, Int64), 0
-// CHECK:     [[ELT0:%.*]] = load [[SPLIT0]] : $*Int64
+// CHECK:     [[ELT0:%.*]] = load [[HOISTADR]] : $*Int64
+// CHECK:     [[HOISTVAL:%.*]] = struct_extract [[ELT0]] : $Int64, #Int64._value
 // ...Split element 2
 // CHECK:     [[SPLIT2:%.*]] = tuple_element_addr %{{.*}} : $*(Int64, Int64, Int64), 2
 // CHECK:     [[ELT2:%.*]] = load [[SPLIT2]] : $*Int64
@@ -1048,8 +1101,6 @@ struct State {
 // CHECK:     [[SINGLEADR:%.*]] = struct_element_addr %{{.*}} : $*State, #State.singleValue
 // CHECK:     [[SINGLEVAL:%.*]] = load [[SINGLEADR]] : $*Int64
 // ...Hoisted element 0
-// CHECK:     [[HOISTLOAD:%.*]] = load [[HOISTADR]] : $*Int64
-// CHECK:     [[HOISTVAL:%.*]] = struct_extract [[HOISTLOAD]] : $Int64, #Int64._value
 // CHECK:     br bb1([[PRELOAD]] : $Int64)
 // ...Loop
 // CHECK:   bb1([[PHI:%.*]] : $Int64):
@@ -1144,6 +1195,41 @@ bb3:
   return %val1 : $(Int64, Int64, Int64)
 }
 
+sil @$foo_read_write : $@convention(method) (Int) -> () {
+[global: read,write]
+}
+
+sil @$foo_read : $@convention(method) (Int) -> () {
+[global: read]
+}
+
+// Read only apply can't be hoisted because of a conflicting write apply in the loop.
+//
+// CHECK-LABEL: sil @test_conflicting_write_apply : $@convention(thin) (Int) -> () {
+// CHECK:      bb2:
+// CHECK-NEXT:   apply
+// CHECK-NEXT:   apply
+// CHECK:      bb3:
+// CHECK-LABEL: } // end sil function 'test_conflicting_write_apply'
+sil @test_conflicting_write_apply : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %4 = function_ref @$foo_read_write : $@convention(method) (Int) -> ()
+  %5 = function_ref @$foo_read : $@convention(method) (Int) -> ()
+  br bb2
+
+bb1:
+  br bb2
+
+bb2:
+  %8 = apply %5(%0) : $@convention(method) (Int) -> ()
+  %9 = apply %4(%0) : $@convention(method) (Int) -> ()
+  cond_br undef, bb3, bb1
+
+bb3:
+  %11 = tuple ()
+  return %11
+}
+
 // Two stores, one to the outer tuple and one to the inner tuple. This
 // results in two access paths that are only loaded/stored to.  First
 // split the outer tuple when processing the outer access path, then
@@ -1157,7 +1243,6 @@ bb3:
 // CHECK:   [[ELT_1a:%.*]] = tuple_element_addr %{{.*}} : $*(Int64, (Int64, Int64)), 1
 // CHECK:   [[ELT_1_0:%.*]] = tuple_element_addr %{{.*}} : $*(Int64, Int64), 0
 // CHECK:   [[V_1_0:%.*]] = load [[ELT_1_0]] : $*Int64
-// CHECK:   [[ELT_1b:%.*]] = tuple_element_addr %{{.*}} : $*(Int64, (Int64, Int64)), 1
 // CHECK:   [[ELT_1_1:%.*]] = tuple_element_addr %{{.*}} : $*(Int64, Int64), 1
 // CHECK:   [[V_1_1:%.*]] = load [[ELT_1_1]] : $*Int64
 // CHECK: br bb1([[V_0:%.*]] : $Int64, [[V_1_0]] : $Int64)
@@ -1232,25 +1317,24 @@ bb3:
   return %val1 : $(Int64, (Int64, Int64))
 }
 
-// Two wide loads. The first can be successfully split and the second
-// half hoisted. The second cannot be split because of a pointer
-// cast. Make sure two remaining loads and the store are still in the loop.
+// Split two wide loads.
 //
 // CHECK-LABEL: sil hidden @testSplitNonStandardProjection : $@convention(method) (Int64, Builtin.RawPointer) -> ((Int64, (Int64, Int64)), (Int64, Int64)) {
 // CHECK: bb0(%0 : $Int64, %1 : $Builtin.RawPointer):
 //
-// The first load was split, so one half is hoisted.
-// CHECK:   [[V1:%.*]] = load %{{.*}} : $*Int64
-// CHECK:   br bb1
-// CHECK: bb1:
-// CHECK:   [[V0:%.*]] = load %{{.*}} : $*Int64
-// CHECK:   [[INNER:%.*]] = tuple ([[V0]] : $Int64, [[V1]] : $Int64)
-// CHECK:   store %0 to %{{.*}} : $*Int64
-// CHECK:   [[OUTER:%.*]] = load %{{.*}} : $*(Int64, (Int64, Int64))
+// CHECK:   [[ADDR1:%.*]] = tuple_element_addr %{{.*}}, 0
+// CHECK:   [[V1:%.*]] = load [[ADDR1]] : $*Int64
+// CHECK:   [[ADDR0:%.*]] = tuple_element_addr %{{.*}}, 1
+// CHECK:   [[V0:%.*]] = load [[ADDR0]] : $*Int64
+// CHECK:   [[OUTER:%.*]] = tuple (%{{.*}} : $Int64, %{{.*}} : $(Int64, Int64))
+// CHECK:   br bb1([[V1]] : $Int64)
+// CHECK: bb1([[PHI:%.*]] : $Int64):
+// CHECK:   [[INNER:%.*]] = tuple ([[PHI]] : $Int64, [[V0]] : $Int64)
 // CHECK:   cond_br undef, bb2, bb3
 // CHECK: bb2:
-// CHECK:   br bb1
+// CHECK:   br bb1(%0 : $Int64)
 // CHECK: bb3:
+// CHECK:   store %0 to [[ADDR1]] : $*Int64
 // CHECK:   [[RESULT:%.*]] = tuple ([[OUTER]] : $(Int64, (Int64, Int64)), [[INNER]] : $(Int64, Int64))
 // CHECK:   return [[RESULT]] : $((Int64, (Int64, Int64)), (Int64, Int64))
 // CHECK-LABEL: } // end sil function 'testSplitNonStandardProjection'
@@ -1282,11 +1366,11 @@ bb3:
 // CHECK: bb0(%0 : $Int64, %1 : $Int64, %2 : $Builtin.RawPointer):
 // CHECK: [[ELT_1:%.*]] = tuple_element_addr %3 : $*(Int64, (Int64, Int64)), 1
 // CHECK: [[V1:%.*]] = load %4 : $*(Int64, Int64)
-// CHECK: [[ELT_0:%.*]] = tuple_element_addr %3 : $*(Int64, (Int64, Int64)), 0
-// CHECK: [[V0:%.*]] = load %6 : $*Int64
 // CHECK: [[ARG0:%.*]] = tuple (%0 : $Int64, %0 : $Int64)
-// CHECK: [[ARG0_0:%.*]] = tuple_extract %8 : $(Int64, Int64), 0
 // CHECK: [[ARG1:%.*]] = tuple (%1 : $Int64, %1 : $Int64)
+// CHECK: [[ELT_0:%.*]] = tuple_element_addr %3 : $*(Int64, (Int64, Int64)), 0
+// CHECK: [[V0:%.*]] = load %9 : $*Int64
+// CHECK: [[ARG0_0:%.*]] = tuple_extract [[ARG0]] : $(Int64, Int64), 0
 // CHECK:   br bb1([[V1]] : $(Int64, Int64))
 // CHECK: bb1([[PHI:%.*]] : $(Int64, Int64)):
 // CHECK:   [[LOOPVAL:%.*]] = tuple ([[V0]] : $Int64, [[PHI]] : $(Int64, Int64))
@@ -1334,8 +1418,10 @@ class C {}
 
 // This won't be hoisted because we can't find a base to check if it is invariant
 // CHECK-LABEL: sil @testLoopInvariantStoreNoBase1 :
+// CHECK: bb3(%11 : $Builtin.RawPointer):
+// CHECK-NOT:   load
 // CHECK: bb6:
-// CHECK-NOT:   store
+// CHECK:       store
 // CHECK-LABEL: } // end sil function 'testLoopInvariantStoreNoBase1'
 sil @testLoopInvariantStoreNoBase1 : $@convention(thin) (Builtin.BridgeObject, Double) -> () {
 bb0(%0 : $Builtin.BridgeObject, %1 : $Double):
@@ -1371,8 +1457,10 @@ bb6:
 
 // This won't be hoisted because we can't find a base to check if it is invariant
 // CHECK-LABEL: sil @testLoopInvariantStoreNoBase2 :
+// CHECK: bb3(%11 : $Builtin.RawPointer):
+// CHECK-NOT: load
 // CHECK: bb6:
-// CHECK-NOT:   store
+// CHECK:     store
 // CHECK-LABEL: } // end sil function 'testLoopInvariantStoreNoBase2'
 sil @testLoopInvariantStoreNoBase2 : $@convention(thin) (Builtin.BridgeObject, Double) -> () {
 bb0(%0 : $Builtin.BridgeObject, %1 : $Double):
@@ -1506,6 +1594,47 @@ bb2:
   return %r1 : $()
 }
 
+struct Outer {
+    var interactions: Inner
+}
+
+public struct Inner {
+    public let x: Int
+    var storage: ContiguousArray<Double>
+}
+
+sil @$get_array_from_inner : $@convention(method) (Inner) -> (ContiguousArray<Double>)
+
+// Make sure we project load access path to matching store access path.
+// Otherwise the pass could crash.
+//
+// CHECK-LABEL: sil @project_load_path_before_splitting_crash :
+// CHECK:         load
+// CHECK:       bb1(%8 : $ContiguousArray<Double>):
+// CHECK:       bb3:
+// CHECK:         store
+// CHECK:       } // end sil function 'project_load_path_before_splitting_crash'
+sil @project_load_path_before_splitting_crash : $@convention(thin) (@inout Outer) -> () {
+bb0(%0 : $*Outer):
+  %1 = struct_element_addr %0, #Outer.interactions
+  %2 = struct_element_addr %1, #Inner.storage
+  br bb1
+
+bb1:
+  %4 = load %1
+  %5 = function_ref @$get_array_from_inner : $@convention(method) (Inner) -> ContiguousArray<Double>
+  %6 = apply %5(%4) : $@convention(method) (Inner) -> ContiguousArray<Double>
+  store %6 to %2
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  %10 = tuple ()
+  return %10
+}
+
 // CHECK-LABEL: sil @dont_hoist_builtin_once_memory_conflict :
 // CHECK:         function_ref
 // CHECK:         br bb1
@@ -1531,11 +1660,14 @@ bb2:
   return %r1 : $()
 }
 
-// CHECK-LABEL: sil [ossa] @dont_hoist_non_trivial_load :
+// CHECK-LABEL: sil [ossa] @hoist_load_copy :
+// CHECK:        %1 = load_borrow %0
 // CHECK:       bb1:
-// CHECK-NEXT:   load [copy]
-// CHECK:       } // end sil function 'dont_hoist_non_trivial_load'
-sil [ossa] @dont_hoist_non_trivial_load : $@convention(thin) (@inout Builtin.NativeObject) -> () {
+// CHECK-NEXT:   %3 = copy_value %1
+// CHECK:       bb3:
+// CHECK-NEXT:   end_borrow %1
+// CHECK:       } // end sil function 'hoist_load_copy'
+sil [ossa] @hoist_load_copy : $@convention(thin) (@inout Builtin.NativeObject) -> () {
 bb0(%0 : $*Builtin.NativeObject):
   br bb1
 bb1:
@@ -1550,9 +1682,59 @@ bb3:
   return %r : $()
 }
 
+// CHECK-LABEL: sil [ossa] @hoist_load_take_store_init :
+// CHECK:        %2 = load [take] %0
+// CHECK:       bb1(%4 : @owned $S):
+// CHECK-NEXT:   fix_lifetime %4
+// CHECK:       bb3:
+// CHECK-NEXT:   store %7 to [init] %0
+// CHECK:       } // end sil function 'hoist_load_take_store_init'
+sil [ossa] @hoist_load_take_store_init : $@convention(thin) (@inout S, @guaranteed S) -> () {
+bb0(%0 : $*S, %new_val : @guaranteed $S):
+  br bb1
+bb1:
+  %2 = load [take] %0
+  fix_lifetime %2
+  destroy_value %2
+  %copied = copy_value %new_val
+  store %copied to [init] %0
+  cond_br undef, bb2, bb3
+bb2:
+  br bb1
+bb3:
+  %r = tuple ()
+  return %r : $()
+}
+
+sil @$foo_yield : $@yield_once @convention(method) (Int) -> @yields Int {
+[global: read]
+}
+
+// CHECK-LABEL: sil [ossa] @hoist_begin_apply : $@convention(thin) (Int) -> () {
+// CHECK:       bb0(%0 : $Int):
+// CHECK:         function_ref
+// CHECK:         begin_apply
+// CHECK:       bb3:
+// CHECK:         end_apply
+// CHECK:       } // end sil function 'hoist_begin_apply'
+sil [ossa] @hoist_begin_apply : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  br bb1
+bb1:
+  %reader = function_ref @$foo_yield : $@yield_once @convention(method) (Int) -> @yields Int
+  (%value, %token) = begin_apply %reader(%0) : $@yield_once @convention(method) (Int) -> @yields Int
+  end_apply %token as $()
+  cond_br undef, bb2, bb3
+bb2:
+  br bb1
+bb3:
+  %r = tuple ()
+  return %r : $()
+}
+
 // CHECK-LABEL: sil [ossa] @hoist_trivial_load :
 // CHECK:         load [trivial]
-// CHECK-NEXT:  br bb1  
+// CHECK-NEXT:  br bb1
 // CHECK:       } // end sil function 'hoist_trivial_load'
 sil [ossa] @hoist_trivial_load : $@convention(thin) (@inout Int) -> () {
 bb0(%0 : $*Int):
@@ -1568,11 +1750,13 @@ bb3:
   return %r : $()
 }
 
-// CHECK-LABEL: sil [ossa] @dont_hoist_load_borrow :
-// CHECK:       bb1:
+// CHECK-LABEL: sil [ossa] @hoist_load_borrow :
+// CHECK:       bb0(%0 : $*Builtin.NativeObject):
 // CHECK-NEXT:    load_borrow
-// CHECK:       } // end sil function 'dont_hoist_load_borrow'
-sil [ossa] @dont_hoist_load_borrow : $@convention(thin) (@inout Builtin.NativeObject) -> () {
+// CHECK:       bb3:
+// CHECK-NEXT:    end_borrow
+// CHECK:       } // end sil function 'hoist_load_borrow'
+sil [ossa] @hoist_load_borrow : $@convention(thin) (@inout Builtin.NativeObject) -> () {
 bb0(%0 : $*Builtin.NativeObject):
   br bb1
 bb1:
@@ -1587,6 +1771,34 @@ bb3:
   return %r : $()
 }
 
+// CHECK-LABEL: sil [ossa] @dont_hoist_load_borrow :
+// CHECK:       bb1:
+// CHECK-NEXT:    copy_addr
+// CHECK-NEXT:    load_borrow
+// CHECK:       } // end sil function 'dont_hoist_load_borrow'
+sil [ossa] @dont_hoist_load_borrow : $@convention(thin) (@in_guaranteed String) -> () {
+bb0(%0 : $*String):
+  %1 = alloc_stack $String
+  br bb1
+
+bb1:
+  copy_addr %0 to [init] %1
+  %3 = load_borrow %1
+  fix_lifetime %3
+  end_borrow %3
+  %6 = load [take] %1
+  destroy_value %6
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  dealloc_stack %1
+  %r = tuple()
+  return %r : $()
+}
+
 // CHECK-LABEL: sil [ossa] @dont_hoist_struct :
 // CHECK:       bb1:
 // CHECK-NEXT:    struct $NonCopyable
@@ -1606,6 +1818,31 @@ bb3:
   return %r : $()
 }
 
+// CHECK-LABEL: sil [ossa] @hoist_store_borrow :
+// CHECK:       bb0(%0 : @guaranteed $S):
+// CHECK-NEXT:    alloc_stack
+// CHECK-NEXT:    store_borrow
+// CHECK:       bb3:
+// CHECK-NEXT:    end_borrow
+// CHECK-NEXT:    dealloc_stack
+// CHECK:       } // end sil function 'hoist_store_borrow'
+sil [ossa] @hoist_store_borrow : $@convention(thin) (@guaranteed S) -> () {
+bb0(%0 : @guaranteed $S):
+  br bb1
+bb1:
+  %s = alloc_stack $S
+  %2 = store_borrow %0 to %s
+  fix_lifetime %2
+  end_borrow %2
+  dealloc_stack %s
+  cond_br undef, bb2, bb3
+bb2:
+  br bb1
+bb3:
+  %r = tuple ()
+  return %r : $()
+}
+
 sil @foo : $@convention(thin) (@guaranteed { var Int }) -> ()
 
 // CHECK-LABEL: sil [ossa] @test_begin_access : $@convention(thin) (Int) -> () {
@@ -1648,7 +1885,7 @@ bb3:
 // CHECK-LABEL: } // end sil function 'store_of_optional_none'
 sil [ossa] @store_of_optional_none : $@convention(thin) () -> () {
 bb0:
-  %0 = enum $Optional<String>, #Optional.none!enumelt 
+  %0 = enum $Optional<String>, #Optional.none!enumelt
   %1 = alloc_stack $Optional<String>
   store %0 to [init] %1
   br bb1
@@ -1667,3 +1904,278 @@ bb3:
   return %r : $()
 }
 
+// CHECK-LABEL: sil [ossa] @store_and_load_borrow :
+// CHECK:       bb1({{.*}}):
+// CHECK:         store %1 to [trivial]
+// CHECK:         load_borrow
+// CHECK:       bb2:
+// CHECK-LABEL: } // end sil function 'store_and_load_borrow'
+sil [ossa] @store_and_load_borrow : $@convention(thin) (@inout S, Int) -> () {
+bb0(%0 : $*S, %1 : $Int):
+  %2 = load_borrow %0
+  %3 = struct_element_addr %0, #S.i
+  br bb1(%2)
+
+bb1(%4 : @reborrow $S):
+  %5 = borrowed %4 from ()
+  end_borrow %5
+  store %1 to [trivial] %3
+  %10 = load_borrow %0
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1(%10)
+
+bb3:
+  br bb4(%10)
+
+bb4(%14 : @reborrow $S):
+  %15 = borrowed %14 from ()
+  end_borrow %15
+  %r = tuple()
+  return %r
+}
+
+// Just check that LICM doesn't produce invalid SIL because of a tuple type mismatch.
+// CHECK-LABEL: sil [ossa] @split_load_of_labeld_tuples :
+// CHECK-LABEL: } // end sil function 'split_load_of_labeld_tuples'
+sil [ossa] @split_load_of_labeld_tuples : $@convention(thin) (@inout Pair, Int) -> () {
+bb0(%0 : $*Pair, %1 : $Int):
+  br bb1
+
+bb1:
+  cond_br undef, bb3, bb2
+
+bb2:
+  %4 = load [trivial] %0
+  %5 = struct_element_addr %0, #Pair.t
+  %6 = tuple_element_addr %5, 0
+  %7 = alloc_stack $Int
+  store %1 to [trivial] %7
+  %9 = load [trivial] %7
+  store %9 to [trivial] %6
+  dealloc_stack %7
+  br bb1
+
+bb3:
+  %13 = tuple ()
+  return %13
+}
+
+// Just check that LICM doesn't produce invalid SIL.
+// CHECK-LABEL: sil [ossa] @uninitialized_at_entry_and_exit :
+// CHECK-LABEL: } // end sil function 'uninitialized_at_entry_and_exit'
+sil [ossa] @uninitialized_at_entry_and_exit : $@convention(thin) (@owned S) -> @out S {
+bb0(%0 : $*S, %1 : @owned $S):
+  br bb1
+
+bb1:
+  %5 = copy_value %1
+  store %5 to [init] %0
+  %7 = load [take] %0
+  destroy_value %7
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  store %1 to [init] %0
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil [ossa] @uninitialized_at_entry :
+// CHECK:       bb1:
+// CHECK-NEXT:    [[C:%.*]] = copy_value %1
+// CHECK-NEXT:    cond_br
+// CHECK:       bb2:
+// CHECK-NEXT:    destroy_value [[C]]
+// CHECK:       bb3:
+// CHECK-NEXT:    store [[C]] to [init] %0
+// CHECK-LABEL: } // end sil function 'uninitialized_at_entry'
+sil [ossa] @uninitialized_at_entry : $@convention(thin) (@owned S) -> @out S {
+bb0(%0 : $*S, %1 : @owned $S):
+  br bb1
+
+bb1:
+  %5 = copy_value %1
+  store %5 to [init] %0
+  cond_br undef, bb2, bb3
+
+bb2:
+  %7 = load [take] %0
+  destroy_value %7
+  br bb1
+
+bb3:
+  destroy_value %1
+  %r = tuple ()
+  return %r
+}
+
+// Just check that LICM doesn't produce invalid SIL.
+// CHECK-LABEL: sil [ossa] @uninitialized_at_exit :
+// CHECK-LABEL: } // end sil function 'uninitialized_at_exit'
+sil [ossa] @uninitialized_at_exit : $@convention(thin) (@in S) -> () {
+bb0(%0 : $*S):
+  br bb1
+
+bb1:
+  %4 = load [take] %0
+  %5 = move_value %4
+  store %5 to [init] %0
+  %6 = load [take] %0
+  cond_br undef, bb2, bb3
+
+bb2:
+  %8 = move_value %6
+  store %8 to [init] %0
+  br bb1
+
+bb3:
+  destroy_value %6
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil [ossa] @projected_load_take :
+// CHECK:       bb1([[V:%.*]] : @owned $(S, Int)):
+// CHECK-NEXT:    ([[E:%.*]], {{%[0-9]+}}) = destructure_tuple [[V]]
+// CHECK-NEXT:    ({{%[0-9]+}}, [[S:%.*]]) = destructure_struct [[E]]
+// CHECK-NEXT:    = struct $S (%1 : $Int, [[S]] : $String)
+// CHECK-LABEL: } // end sil function 'projected_load_take'
+sil [ossa] @projected_load_take : $@convention(thin) (@inout (S, Int), Int) -> () {
+bb0(%0 : $*(S, Int), %1 : $Int):
+  br bb1
+
+bb1:
+  %2 = tuple_element_addr %0, 0
+  %3 = struct_element_addr %2, #S.s
+  %4 = load [take] %3
+  %5 = struct $S (%1, %4)
+  %6 = tuple (%5, %1)
+  store %6 to [init] %0
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil [ossa] @load_copy_followed_by_take :
+// CHECK:       bb1([[V:%.*]] : @owned $S):
+// CHECK-NEXT:    [[C:%.*]] = copy_value [[V]]
+// CHECK-NEXT:    destroy_value [[C]]
+// CHECK-NEXT:      = move_value [[V]]
+// CHECK-LABEL: } // end sil function 'load_copy_followed_by_take'
+sil [ossa] @load_copy_followed_by_take : $@convention(thin) (@inout S) -> () {
+bb0(%0 : $*S):
+  br bb1
+
+bb1:
+  %4 = load [copy] %0
+  destroy_value %4
+  %6 = load [take] %0
+  %7 = move_value %6
+  store %7 to [init] %0
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil [ossa] @projected_load_copy_followed_by_take :
+// CHECK:       bb1([[V:%.*]] : @owned $S):
+// CHECK-NEXT:    [[B:%.*]] = begin_borrow [[V]]
+// CHECK-NEXT:    [[SE:%.*]] = struct_extract [[B]]
+// CHECK-NEXT:    [[C:%.*]] = copy_value [[SE]]
+// CHECK-NEXT:    end_borrow [[B]]
+// CHECK-NEXT:    destroy_value [[C]]
+// CHECK-NEXT:    ({{%[0-9]+}}, [[S:%.*]]) = destructure_struct [[V]]
+// CHECK-NEXT:      = struct $S (%1 : $Int, [[S]] : $String)
+// CHECK-LABEL: } // end sil function 'projected_load_copy_followed_by_take'
+sil [ossa] @projected_load_copy_followed_by_take : $@convention(thin) (@inout S, Int) -> () {
+bb0(%0 : $*S, %1 : $Int):
+  br bb1
+
+bb1:
+  %43 = struct_element_addr %0, #S.s
+  %4 = load [copy] %43
+  destroy_value %4
+  %48 = load [take] %43
+  %49 = struct $S (%1, %48)
+  store %49 to [init] %0
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  %r = tuple ()
+  return %r
+}
+
+// Just check that LICM doesn't produce invalid SIL.
+// CHECK-LABEL: sil [ossa] @partial_load_take_is_not_supported :
+// CHECK-LABEL: } // end sil function 'partial_load_take_is_not_supported'
+sil [ossa] @partial_load_take_is_not_supported : $@convention(thin) (@inout S2, Int) -> () {
+bb0(%0 : $*S2, %1 : $Int):
+  br bb1
+
+bb1:
+  %4 = struct_element_addr %0, #S2.s1
+  %5 = load [take] %4
+  %6 = struct_element_addr %0, #S2.s2
+  %7 = load [take] %6
+  %8 = struct $S2 (%1, %5, %7)
+  store %8 to [init] %0
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil [ossa] @partial_load_copy :
+// CHECK:       bb1([[V:%.*]] : @owned $S2):
+// CHECK:          [[B1:%.*]] = begin_borrow [[V]]
+// CHECK-NEXT:     [[SE1:%.*]] = struct_extract [[B1]] : $S2, #S2.s1
+// CHECK-NEXT:       = copy_value [[SE1]]
+// CHECK:          [[B2:%.*]] = begin_borrow [[V]]
+// CHECK-NEXT:     [[SE2:%.*]] = struct_extract [[B2]] : $S2, #S2.s2
+// CHECK-NEXT:       = copy_value [[SE2]]
+// CHECK-LABEL: } // end sil function 'partial_load_copy'
+sil [ossa] @partial_load_copy : $@convention(thin) (@inout S2, Int) -> () {
+bb0(%0 : $*S2, %1 : $Int):
+  br bb1
+
+bb1:
+  %4 = struct_element_addr %0, #S2.s1
+  %5 = load [copy] %4
+  %6 = struct_element_addr %0, #S2.s2
+  %7 = load [copy] %6
+  %8 = struct $S2 (%1, %5, %7)
+  %9 = load [take] %0
+  destroy_value %9
+  store %8 to [init] %0
+  cond_br undef, bb2, bb3
+
+bb2:
+  br bb1
+
+bb3:
+  %r = tuple ()
+  return %r
+}
+
diff --git a/test/SILOptimizer/licm_apply.sil b/test/SILOptimizer/licm_apply.sil
index df5a5381a2731..77fe0bf6b5a4f 100644
--- a/test/SILOptimizer/licm_apply.sil
+++ b/test/SILOptimizer/licm_apply.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -compute-side-effects -licm | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -compute-side-effects -loop-invariant-code-motion | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 
diff --git a/test/SILOptimizer/licm_exclusivity.sil b/test/SILOptimizer/licm_exclusivity.sil
index 5f73b9648b756..fcfe9770af4be 100644
--- a/test/SILOptimizer/licm_exclusivity.sil
+++ b/test/SILOptimizer/licm_exclusivity.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enforce-exclusivity=checked -enable-sil-verify-all %s -licm | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enforce-exclusivity=checked -enable-sil-verify-all %s -loop-invariant-code-motion | %FileCheck %s
 
 sil_stage canonical
 
@@ -153,10 +153,12 @@ bb2:
 // CHECK-LABEL: sil @hoist_access_static : $@convention(thin) () -> () {
 // CHECK: [[GLOBAL:%.*]] = global_addr @globalX : $*X
 // CHECK: [[BEGIN:%.*]] = begin_access [read] [static] [[GLOBAL]] : $*X
-// CHECK-NEXT: load
-// CHECK-NEXT: br bb1
+
+// Currently disabled because of a workaround in AliasAnalysis: rdar://151841926
+// xCHECK-NEXT: load
+// xCHECK-NEXT: br bb1
 // CHECK: apply
-// CHECK-NEXT: cond_br
+// xCHECK-NEXT: cond_br
 // CHECK: bb2
 // CHECK: end_access [[BEGIN]]
 // CHECK-LABEL: } // end sil function 'hoist_access_static'
diff --git a/test/SILOptimizer/licm_exclusivity.swift b/test/SILOptimizer/licm_exclusivity.swift
index b743c5996ac2f..0b9f56e6bd889 100644
--- a/test/SILOptimizer/licm_exclusivity.swift
+++ b/test/SILOptimizer/licm_exclusivity.swift
@@ -1,22 +1,17 @@
-// RUN: %target-swift-frontend -O -enforce-exclusivity=checked -Xllvm -sil-print-types -emit-sil -Xllvm -debug-only=sil-licm -primary-file %s 2>&1 | %FileCheck %s --check-prefix=TESTLICM
-// RUN: %target-swift-frontend -O -enforce-exclusivity=checked -Xllvm -sil-print-types -emit-sil -Xllvm -debug-only=sil-licm -primary-file %s 2>&1 | %FileCheck %s --check-prefix=TESTLICM2
 // RUN: %target-swift-frontend -O -enforce-exclusivity=checked -Xllvm -sil-print-types -emit-sil  -primary-file %s | %FileCheck %s --check-prefix=TESTSIL
-// RUN: %target-swift-frontend -O -enforce-exclusivity=checked -Xllvm -sil-print-types -emit-sil -Xllvm -debug-only=sil-licm -whole-module-optimization %s 2>&1 | %FileCheck %s --check-prefix=TESTLICMWMO
 // RUN: %target-swift-frontend -O -enforce-exclusivity=checked -Xllvm -sil-print-types -emit-sil  -whole-module-optimization %s | %FileCheck %s --check-prefix=TESTSILWMO
 
 // REQUIRES: optimized_stdlib,asserts,swift_stdlib_no_asserts
 // REQUIRES: PTRSIZE=64
 
-// TESTLICM-LABEL: Processing loops in {{.*}}run_ReversedArray{{.*}}
-// TESTLICM: Hoist and Sink pairs attempt
-// TESTLICM: Hoisted
-// TESTLICM: Successfully hoisted and sank pair
-
 // TESTSIL-LABEL: sil hidden @$s16licm_exclusivity17run_ReversedArrayyySiF : $@convention(thin) (Int) -> () {
 // TESTSIL: bb
 // TESTSIL: begin_access [modify] [dynamic] [no_nested_conflict]
 // TESTSIL: br bb{{.*}}
-// TESTSIL-NEXT bb{{.*}}:
+// TESTSIL-EMPTY:
+// TESTSIL-NEXT: {{^}}//
+// TESTSIL-NEXT: {{^}}//
+// TESTSIL-NEXT: bb{{.*}}:
 // TESTSIL: end_access
 var x = 0
 func run_ReversedArray(_ N: Int) {
@@ -32,10 +27,6 @@ func run_ReversedArray(_ N: Int) {
   }
 }
 
-// TESTLICM2-LABEL: Processing loops in {{.*}}count_unicodeScalars{{.*}}
-// TESTLICM2: Hoist and Sink pairs attempt
-// TESTLICM2: Hoisted
-
 // TESTSIL-LABEL: sil @$s16licm_exclusivity20count_unicodeScalarsyySS17UnicodeScalarViewVF : $@convention(thin) (@guaranteed String.UnicodeScalarView) -> () {
 // TESTSIL: bb0(%0 : $String.UnicodeScalarView)
 // TESTSIL: bb5:
@@ -63,12 +54,6 @@ public class ClassWithArrs {
     B = [Int](repeating: 0, count: N)
   }
 
-// TESTLICMWMO-LABEL: Processing loops in {{.*}}ClassWithArrsC7readArr{{.*}}
-// TESTLICMWMO: Hoist and Sink pairs attempt
-// TESTLICMWMO: Hoisted
-// TESTLICMWMO: Successfully hoisted and sank pair
-// TESTLICMWMO: Hoisted
-// TESTLICMWMO: Successfully hoisted and sank pair
 // TESTSILWMO-LABEL: sil {{.*}}@$s16licm_exclusivity13ClassWithArrsC7readArryyF : $@convention(method) (@guaranteed ClassWithArrs) -> () {
 // TESTSILWMO: [[R1:%.*]] = ref_element_addr %0 : $ClassWithArrs, #ClassWithArrs.A
 // TESTSILWMO: [[R2:%.*]] = ref_element_addr %0 : $ClassWithArrs, #ClassWithArrs.B
diff --git a/test/SILOptimizer/licm_multiend.sil b/test/SILOptimizer/licm_multiend.sil
index 32d83b3d14ad6..5a22419f66b5f 100644
--- a/test/SILOptimizer/licm_multiend.sil
+++ b/test/SILOptimizer/licm_multiend.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -licm | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -loop-invariant-code-motion | %FileCheck %s
 // REQUIRES: PTRSIZE=64
 // REQUIRES: OS=macosx
 
diff --git a/test/SILOptimizer/licm_unreferenceablestorage.sil b/test/SILOptimizer/licm_unreferenceablestorage.sil
index d4d4686344fb7..6a93057fb51f5 100644
--- a/test/SILOptimizer/licm_unreferenceablestorage.sil
+++ b/test/SILOptimizer/licm_unreferenceablestorage.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -licm | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -loop-invariant-code-motion | %FileCheck %s
 
 // REQUIRES: objc_interop
 
diff --git a/test/SILOptimizer/lifetime_dependence/Inputs/lifetime_depend_diagnose.swiftinterface b/test/SILOptimizer/lifetime_dependence/Inputs/lifetime_depend_diagnose.swiftinterface
new file mode 100644
index 0000000000000..ddda8c264bf92
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/Inputs/lifetime_depend_diagnose.swiftinterface
@@ -0,0 +1,47 @@
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name lifetime_depend_diagnose -enable-experimental-feature Lifetimes -swift-version 5 -enable-library-evolution
+import Swift
+import _Concurrency
+import _StringProcessing
+import _SwiftConcurrencyShims
+
+#if $LifetimeDependence
+public struct NE : ~Swift.Escapable {
+  @usableFromInline
+  internal let _pointer: Swift.UnsafeRawPointer?
+
+  @_lifetime(borrow pointer)
+  public init(pointer: Swift.UnsafeRawPointer?) {
+    self._pointer = pointer
+  }
+}
+
+extension NE {
+  // This is illegal at the source level because NE.init is implicitly @lifetime(borrow),
+  // so we can't return it as dependent on @lifetime(copy self).
+  @_lifetime(copy self)
+  @unsafe @_alwaysEmitIntoClient public func forward() -> NE {
+    return NE(pointer: _pointer)
+  }
+}
+
+public struct NCNE<Element>: ~Swift.Copyable & ~Swift.Escapable {
+  var e: Element
+}
+
+extension NCNE where Element : Swift.BitwiseCopyable {
+  // Ensure that lifetime dependence diagnostics accessp the generated _modify accessor:
+  // the getter dependency must match the setter's mewValue dependence.
+  // In this case, the getter has no dependency because the result is BitwiseCopyable. The setter cannot, therefore,
+  // have a borrow dependency no 'newValue' which is produced by the getter.
+  public subscript() -> Element {
+    get {
+      return e
+    }
+    //@lifetime(self: copy self, self: copy newValue)
+    set {
+      e = newValue
+    }
+  }
+}
+#endif
diff --git a/test/SILOptimizer/lifetime_dependence/accessors.swift b/test/SILOptimizer/lifetime_dependence/accessors.swift
new file mode 100644
index 0000000000000..53061c5d53bbe
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/accessors.swift
@@ -0,0 +1,81 @@
+// RUN: %target-swift-emit-sil -enable-experimental-feature Lifetimes -primary-file %s | %FileCheck %s
+
+// REQUIRES: swift_feature_Lifetimes
+
+struct NE : ~Escapable {
+  let _p: UnsafeRawPointer
+
+  @_lifetime(borrow p)
+  init(_ p: UnsafeRawPointer) { self._p = p }
+}
+
+struct NCNE : ~Copyable, ~Escapable {
+  let _p: UnsafeRawPointer
+
+  @_lifetime(borrow p)
+  init(_ p: UnsafeRawPointer) {
+    self._p = p
+  }
+}
+
+struct NEStoredProp : ~Escapable {
+  var ne: NE
+  // NEStoredProp.ne.getter
+  // CHECK-LABEL: sil hidden [transparent] @$s9accessors12NEStoredPropV2neAA2NEVvg : $@convention(method) (@guaranteed NEStoredProp) -> @lifetime(copy 0) @owned NE {
+
+  // NEStoredProp.ne.setter
+  // CHECK-LABEL: sil hidden [transparent] @$s9accessors12NEStoredPropV2neAA2NEVvs : $@convention(method) (@owned NE, @lifetime(copy 0, copy 1) @inout NEStoredProp) -> () {
+
+  // NEStoredProp.ne.modify
+  // CHECK-LABEL: sil hidden [transparent] @$s9accessors12NEStoredPropV2neAA2NEVvM : $@yield_once @convention(method) (@lifetime(copy 0) @inout NEStoredProp) -> @lifetime(copy 0) @yields @inout NE {
+
+  // NEStoredProp.init(ne:)
+  // CHECK-LABEL: sil hidden @$s9accessors12NEStoredPropV2neAcA2NEV_tcfC : $@convention(method) (@owned NE, @thin NEStoredProp.Type) -> @lifetime(copy 0) @owned NEStoredProp {
+}
+
+struct NCNEStoredProp : ~Copyable & ~Escapable {
+  var ncne: NCNE
+  // NCNEStoredProp.ncne.read
+  // CHECK-LABEL: sil hidden [transparent] @$s9accessors14NCNEStoredPropV4ncneAA4NCNEVvr : $@yield_once @convention(method) (@guaranteed NCNEStoredProp) -> @lifetime(copy 0) @yields @guaranteed NCNE {
+
+  // NCNEStoredProp.ncne.setter
+  // CHECK-LABEL: sil hidden [transparent] @$s9accessors14NCNEStoredPropV4ncneAA4NCNEVvs : $@convention(method) (@owned NCNE, @lifetime(copy 0, copy 1) @inout NCNEStoredProp) -> () {
+
+  // NCNEStoredProp.ncne.modify
+  // CHECK-LABEL: sil hidden [transparent] @$s9accessors14NCNEStoredPropV4ncneAA4NCNEVvM : $@yield_once @convention(method) (@lifetime(copy 0) @inout NCNEStoredProp) -> @lifetime(copy 0) @yields @inout NCNE {
+
+  // NCNEStoredProp.init(ncne:)
+  // CHECK-LABEL: sil hidden @$s9accessors14NCNEStoredPropV4ncneAcA4NCNEV_tcfC : $@convention(method) (@owned NCNE, @thin NCNEStoredProp.Type) -> @lifetime(copy 0) @owned NCNEStoredProp {
+}
+
+struct NCNEHolder : ~Copyable, ~Escapable {
+  var p: UnsafeRawPointer
+
+  // this cannot be public in order to synthesize the _read accessor.
+  var ncneBorrow: NCNE {
+    // CHECK-LABEL: sil{{.*}} @$s9accessors10NCNEHolderV10ncneBorrowAA4NCNEVvr : $@yield_once @convention(method) (@guaranteed NCNEHolder) -> @lifetime(borrow 0) @yields @guaranteed NCNE {
+    @_lifetime(borrow self)
+    borrowing get {
+      _overrideLifetime(NCNE(p), borrowing: self)
+    }
+    // CHECK-LABEL: sil{{.*}} @$s9accessors10NCNEHolderV10ncneBorrowAA4NCNEVvM : $@yield_once @convention(method) (@lifetime(copy 0) @inout NCNEHolder) -> @lifetime(borrow 0) @yields @inout NCNE {
+    @_lifetime(self: copy self)
+    set {
+      p = newValue._p
+    }
+  }
+
+  // this cannot be public in order to synthesize the _read accessor.
+  var ncneCopy: NCNE {
+    // CHECK-LABEL: sil{{.*}} @$s9accessors10NCNEHolderV8ncneCopyAA4NCNEVvr : $@yield_once @convention(method) (@guaranteed NCNEHolder) -> @lifetime(copy 0) @yields @guaranteed NCNE {
+    @_lifetime(copy self)
+    borrowing get {
+      _overrideLifetime(NCNE(p), copying: self)
+    }
+    // CHECK-LABEL: sil{{.*}} @$s9accessors10NCNEHolderV8ncneCopyAA4NCNEVvM : $@yield_once @convention(method) (@lifetime(copy 0) @inout NCNEHolder) -> @lifetime(copy 0) @yields @inout NCNE {
+    @_lifetime(self: copy self)
+    set {
+      p = newValue._p
+    }
+  }
+}
diff --git a/test/SILOptimizer/lifetime_dependence/addressable_lifetime_with_resilience.swift b/test/SILOptimizer/lifetime_dependence/addressable_lifetime_with_resilience.swift
new file mode 100644
index 0000000000000..2f3e01a460334
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/addressable_lifetime_with_resilience.swift
@@ -0,0 +1,35 @@
+// RUN: %target-swift-frontend -enable-experimental-feature AddressableTypes -enable-experimental-feature Lifetimes -enable-library-evolution -emit-sil -verify %s
+
+// REQUIRES: swift_feature_AddressableTypes
+// REQUIRES: swift_feature_Lifetimes
+
+internal struct Wrapper {
+    let inner: Resilient
+
+    @_lifetime(borrow self)
+    borrowing func getSpan() -> RawSpan { self.inner.getSpan() }
+}
+
+public struct Resilient {
+    var field: AnyObject
+
+    @_lifetime(borrow self)
+    borrowing func getSpan() -> RawSpan { fatalError() }
+}
+
+/*
+// TODO (rdar://151268401): We still get spurious errors about escaping `self`
+// in cases where the wrapped type is concretely addressable-for-dependencies.
+internal struct AFDWrapper {
+    let inner: AFDResilient
+
+    @_lifetime(borrow self)
+    borrowing func getSpan() -> RawSpan { self.inner.getSpan() }
+}
+
+@_addressableForDependencies
+public struct AFDResilient {
+    @_lifetime(borrow self)
+    borrowing func getSpan() -> RawSpan { fatalError() }
+}
+*/
diff --git a/test/SILOptimizer/lifetime_dependence/coroutine.swift b/test/SILOptimizer/lifetime_dependence/coroutine.swift
index 3ee01ab89185b..aab9b7c88dcd7 100644
--- a/test/SILOptimizer/lifetime_dependence/coroutine.swift
+++ b/test/SILOptimizer/lifetime_dependence/coroutine.swift
@@ -1,19 +1,19 @@
 // RUN: %target-swift-frontend %s -emit-sil \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct View : ~Escapable {
   let ptr: UnsafeRawBufferPointer
   let c: Int
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(_ ptr: UnsafeRawBufferPointer, _ c: Int) {
     self.ptr = ptr
     self.c = c
   }
-  @lifetime(copy otherBV)
+  @_lifetime(copy otherBV)
   init(_ otherBV: borrowing View) {
     self.ptr = otherBV.ptr
     self.c = otherBV.c
@@ -24,7 +24,7 @@ struct View : ~Escapable {
   }
   // This overload requires a separate label because overloading
   // on borrowing/consuming attributes is not allowed
-  @lifetime(copy k)
+  @_lifetime(copy k)
   init(consumingView k: consuming View) {
     self.ptr = k.ptr
     self.c = k.c
@@ -36,16 +36,16 @@ struct Wrapper : ~Escapable {
 
   // Nested coroutine access.
   var view: View {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield _view
     }
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &_view
     }
   }
-  @lifetime(copy view)
+  @_lifetime(copy view)
   init(_ view: consuming View) {
     self._view = view
   }
@@ -86,20 +86,21 @@ func use(_ o : borrowing View) {}
 //       let wrapper = nc.wrapper
 // CHECK:   [[ACCESS:%.*]] = begin_access [read] [static] [[NC]]
 // CHECK:   [[NCVAL:%.*]] = load [[ACCESS]] 
-// CHECK:   ([[YIELD1:%.*]], [[TOKEN1:%.*]]) = begin_apply %{{.*}}([[NCVAL]]) : $@yield_once @convention(method) (@guaranteed NCContainer) -> @lifetime(borrow 0) @yields @guaranteed Wrapper
-// CHECK:   [[WRAPPER:%.*]] = mark_dependence [nonescaping] [[YIELD1]] on [[TOKEN1]]
-// CHECK:   retain_value [[WRAPPER]]
-// CHECK:   debug_value [[WRAPPER]], let, name "wrapper"
+// CHECK:   ([[WRAPPER:%.*]], [[TOKEN1:%.*]]) = begin_apply %{{.*}}([[NCVAL]]) : $@yield_once @convention(method) (@guaranteed NCContainer) -> @lifetime(borrow 0) @yields @guaranteed Wrapper
+// CHECK:   [[SCOPE:%.*]] = mark_dependence [nonescaping] [[WRAPPER]] on [[TOKEN1]]
+// CHECK:   [[MDI:%.*]] = mark_dependence [nonescaping] [[SCOPE]] on [[ACCESS]]
+// CHECK:   retain_value [[MDI]]
+// CHECK:   debug_value [[MDI]], let, name "wrapper"
 //       let view = wrapper.view
-// CHECK:   ([[VIEW:%.*]], [[TOKEN2:%.*]]) = begin_apply %{{.*}}([[WRAPPER]]) : $@yield_once @convention(method) (@guaranteed Wrapper) -> @lifetime(copy 0) @yields @guaranteed View
+// CHECK:   ([[VIEW:%.*]], [[TOKEN2:%.*]]) = begin_apply %{{.*}}([[MDI]]) : $@yield_once @convention(method) (@guaranteed Wrapper) -> @lifetime(copy 0) @yields @guaranteed View
 // CHECK:   retain_value [[VIEW]]
 // CHECK:   end_apply [[TOKEN2]] as $()
 // CHECK:   debug_value [[VIEW]], let, name "view"
 //       use(view)
 // CHECK:   apply %{{.*}}([[VIEW]]) : $@convention(thin) (@guaranteed View) -> ()
 // CHECK:   release_value [[VIEW]]
-// CHECK:   release_value [[WRAPPER]]
-// CHECK:   %24 = end_apply [[TOKEN1]] as $()
+// CHECK:   release_value [[MDI]]
+// CHECK:   end_apply [[TOKEN1]] as $()
 // CHECK:   end_access [[ACCESS]]
 // CHECK:   destroy_addr [[NC]]
 // CHECK-LABEL: } // end sil function '$s9coroutine20testDoubleNestedRead2ncyAA11NCContainerVn_tF'
diff --git a/test/SILOptimizer/lifetime_dependence/dependence_insertion.sil b/test/SILOptimizer/lifetime_dependence/dependence_insertion.sil
index 5efefb9d2661a..b031ab639586d 100644
--- a/test/SILOptimizer/lifetime_dependence/dependence_insertion.sil
+++ b/test/SILOptimizer/lifetime_dependence/dependence_insertion.sil
@@ -2,13 +2,13 @@
 // RUN:   -lifetime-dependence-insertion \
 // RUN:   -enable-address-dependencies \
 // RUN:   -sil-verify-all \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-feature AddressableParameters \
 // RUN:   -enable-experimental-feature AddressableTypes \
 // RUN:   %s | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_AddressableParameters
 // REQUIRES: swift_feature_AddressableTypes
 
@@ -19,14 +19,14 @@ import Swift
 struct NE: ~Escapable {
   var p: UnsafeRawPointer
 
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init()
 }
 
 struct NCE: ~Escapable, ~Copyable {
   var p: UnsafeRawPointer
 
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init()
 }
 
@@ -41,12 +41,17 @@ struct Holder {
 @_addressableForDependencies
 struct AddressableForDeps {}
 
+protocol PAny : ~Copyable, ~Escapable {}
+
 sil @getPtr : $@convention(thin) () -> @out UnsafeRawPointer
 sil @getSpan : $@convention(thin) (@in_guaranteed AnyObject) -> @lifetime(borrow 0) @out NE
 sil @getInoutSpan : $@convention(thin) (@inout AnyObject) -> @lifetime(borrow 0) @out NCE
 
 sil @useNE : $@convention(thin) (@guaranteed NE) -> ()
 
+sil @getExistential : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @out any PAny & ~Copyable & ~Escapable
+sil @useExistential : $@convention(thin) (@in_guaranteed any PAny & ~Copyable & ~Escapable) -> ()
+ 
 // Check that the inserted dependence is on the 'self' argument, not the temporary borrow.
 //
 // CHECK-LABEL: sil [available 9999] [ossa] @testSpanProp : $@convention(method) (@guaranteed AnyObject) -> @lifetime(borrow 0) @owned NE {
@@ -172,3 +177,31 @@ bb0(%0 : @guaranteed $Holder):
   %99 = tuple ()
   return %99 : $()
 }
+
+// Test that source of a dependency may be a project_box and the mark_dependence will be inserted.
+//
+// CHECK-LABEL: sil hidden [ossa] @testBoxDependenceSource : $@convention(thin) (@inout Holder) -> () {
+// CHECK: [[BOX:%[0-9]+]] = project_box %2, 0
+// CHECK: [[ARG:%[0-9]+]] = begin_access [modify] [unknown] %0
+// CHECK: apply %{{.*}}([[BOX]], [[ARG]]) : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @out any PAny & ~Copyable & ~Escapable
+// CHECK: mark_dependence_addr [unresolved] [[BOX]] on [[ARG]]
+// CHECK-LABEL: } // end sil function 'testBoxDependenceSource'
+sil hidden [ossa] @testBoxDependenceSource : $@convention(thin) (@inout Holder) -> () {
+bb0(%0 : $*Holder):
+  %1 = alloc_box ${ let any PAny & ~Copyable & ~Escapable }, let, name "span"
+  %2 = begin_borrow [lexical] [var_decl] %1
+  %3 = project_box %2, 0
+  %4 = begin_access [modify] [unknown] %0
+
+  %5 = function_ref @getExistential : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @out any PAny & ~Copyable & ~Escapable
+  %6 = apply %5(%3, %4) : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @out any PAny & ~Copyable & ~Escapable
+  end_access %4
+  %8 = mark_unresolved_non_copyable_value [no_consume_or_assign] %3
+
+  %9 = function_ref @useExistential : $@convention(thin) (@in_guaranteed any PAny & ~Copyable & ~Escapable) -> ()
+  %10 = apply %9(%8) : $@convention(thin) (@in_guaranteed any PAny & ~Copyable & ~Escapable) -> ()
+  end_borrow %2
+  destroy_value %1
+  %13 = tuple ()
+  return %13
+}
diff --git a/test/SILOptimizer/lifetime_dependence/dependence_insertion.swift b/test/SILOptimizer/lifetime_dependence/dependence_insertion.swift
index f3cf707c6e9b4..35a0cdf592a1e 100644
--- a/test/SILOptimizer/lifetime_dependence/dependence_insertion.swift
+++ b/test/SILOptimizer/lifetime_dependence/dependence_insertion.swift
@@ -5,36 +5,23 @@
 // RUN:   -module-name test \
 // RUN:   -define-availability "Span 0.1:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999" \
 // RUN:   -enable-address-dependencies \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-feature AddressableParameters \
 // RUN:   -enable-experimental-feature AddressableTypes \
 // RUN:   -o /dev/null 2>&1 | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_AddressableParameters
 // REQUIRES: swift_feature_AddressableTypes
 
 import Builtin
 
-@unsafe
-@_unsafeNonescapableResult
-@_alwaysEmitIntoClient
-@_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, borrowing source: borrowing U
-) -> T {
-  dependent
-}
-
 struct BV : ~Escapable {
   let p: UnsafeRawPointer
   let i: Int
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
@@ -46,7 +33,7 @@ struct NC : ~Copyable {
   let i: Int
 
   // Requires a borrow.
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func getBV() -> BV {
     BV(p, i)
   }
@@ -89,11 +76,44 @@ func bv_borrow_var(p: UnsafeRawPointer, i: Int) {
 // CHECK: [[MD:%.*]] = mark_dependence [unresolved] [[BV]] on %0
 // CHECK: return [[MD]]
 // CHECK-LABEL: } // end sil function '$s4test18bv_pointer_convert1pAA2BVVSPySiG_tF'
-@lifetime(borrow p)
+@_lifetime(borrow p)
 func bv_pointer_convert(p: UnsafePointer<Int>) -> BV {
   BV(p, 0)
 }
 
+// =============================================================================
+// Builtin.addressOfBorrow
+// =============================================================================
+
+// swift-frontend -emit-sil -enable-builtin-module -enable-experimental-feature Lifetimes -enable-experimental-feature AddressableParameters -Xllvm -sil-print-function=test ./dependsOnAddress.swift
+
+import Builtin
+
+struct IntHolder {
+  var field: Int
+}
+
+struct NERawPointer: ~Escapable {
+  var p: Builtin.RawPointer
+}
+
+@_lifetime(borrow x)
+func pointerDepends(on x: Builtin.RawPointer) -> NERawPointer {
+  NERawPointer(p: x)
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s4test0A22BuiltinAddressOfBorrow6holderAA12NERawPointerVAA9IntHolderVz_tF : $@convention(thin) (@inout IntHolder) -> @lifetime(borrow 0) @owned NERawPointer {
+// CHECK: bb0(%0 : $*IntHolder):
+// CHECK: [[ACCESS:%[0-9]+]] = begin_access [read] [static] %0
+// CHECK: [[PTR:%[0-9]+]] = address_to_pointer [stack_protection] %2 to $Builtin.RawPointer
+// CHECK: [[NE:%[0-9]+]] = apply %{{.*}}([[PTR]]) : $@convention(thin) (Builtin.RawPointer) -> @lifetime(borrow 0) @owned NERawPointer
+// CHECK: mark_dependence [unresolved] [[NE]] on %0
+// CHECK-LABEL: } // end sil function '$s4test0A22BuiltinAddressOfBorrow6holderAA12NERawPointerVAA9IntHolderVz_tF'
+@_lifetime(&holder)
+func testBuiltinAddressOfBorrow(holder: inout IntHolder) -> NERawPointer {
+  pointerDepends(on: Builtin.addressOfBorrow(holder))
+}
+
 // =============================================================================
 // @_addressableForDependencies
 // =============================================================================
@@ -103,7 +123,7 @@ public typealias IntSpan = Span<Int>
 
 @available(Span 0.1, *)
 protocol IntSpanable {
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   func getIntSpan() -> IntSpan
 }
 
@@ -120,7 +140,7 @@ public struct Holder: IntSpanable {
     }
   }
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   func getIntSpan() -> IntSpan {
     let span = unsafe Span(_unsafeStart: p, count: 1)
     return unsafe _overrideLifetime(span, borrowing: self)
@@ -138,7 +158,7 @@ public struct InlineHolder: IntSpanable {
     self.i = c.i
   }
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   func getIntSpan() -> IntSpan {
     let a = Builtin.addressOfBorrow(self)
     let address = unsafe UnsafePointer<Int>(a)
@@ -149,7 +169,7 @@ public struct InlineHolder: IntSpanable {
 
 // 'some Spanable' is AddressableForDependencies.
 @available(Span 0.1, *)
-@lifetime(borrow spanable)
+@_lifetime(borrow spanable)
 func getIntSpan(_ spanable: some IntSpanable) -> IntSpan {
   spanable.getIntSpan()
 }
diff --git a/test/SILOptimizer/lifetime_dependence/diagnose_interface.swift b/test/SILOptimizer/lifetime_dependence/diagnose_interface.swift
new file mode 100644
index 0000000000000..eaa05d4524f69
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/diagnose_interface.swift
@@ -0,0 +1,13 @@
+// RUN: %target-swift-frontend %s -emit-sil \
+// RUN:   -o /dev/null \
+// RUN:   -I %S/Inputs \
+// RUN:   -verify \
+// RUN:   -enable-experimental-feature LifetimeDependence
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_LifetimeDependence
+
+// Test that lifetime dependence diagnostics continues to older (early
+// 2025) .swiftinterface files. Source-level diagnostics are stricter.
+
+import lifetime_depend_diagnose
diff --git a/test/SILOptimizer/lifetime_dependence/diagnostic_passes.sil b/test/SILOptimizer/lifetime_dependence/diagnostic_passes.sil
index 7d93685889473..b1c76fc223fba 100644
--- a/test/SILOptimizer/lifetime_dependence/diagnostic_passes.sil
+++ b/test/SILOptimizer/lifetime_dependence/diagnostic_passes.sil
@@ -1,5 +1,5 @@
 // RUN: %target-sil-opt %s \
-// RUN:     -diagnostics -sil-verify-all \
+// RUN:     -diagnostics -sil-verify-all -sil-disable-pass=onone-simplification \
 // RUN:     -enable-experimental-feature LifetimeDependence \
 // RUN:     | %FileCheck %s
 
diff --git a/test/SILOptimizer/lifetime_dependence/initializer.swift b/test/SILOptimizer/lifetime_dependence/initializer.swift
index 13f0ad684d453..42916fd6c51b2 100644
--- a/test/SILOptimizer/lifetime_dependence/initializer.swift
+++ b/test/SILOptimizer/lifetime_dependence/initializer.swift
@@ -3,10 +3,10 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct Span<T>: ~Escapable {
   private var base: UnsafePointer<T>
@@ -18,7 +18,7 @@ struct Span<T>: ~Escapable {
     self.count = count
   }
 
-  @lifetime(borrow generic)
+  @_lifetime(borrow generic)
   init<S>(base: UnsafePointer<T>, count: Int, generic: borrowing S) {
     self.base = base
     self.count = count
@@ -28,7 +28,7 @@ struct Span<T>: ~Escapable {
 struct Wrapper<T: BitwiseCopyable>: ~Escapable {
   private let span: Span<T>
 
-  @lifetime(copy span)
+  @_lifetime(copy span)
   init(span: borrowing Span<T>) {
     self.span = copy span
   }
@@ -42,7 +42,7 @@ struct SuperWrapper<T: BitwiseCopyable>: ~Escapable {
 
   // Make sure that LocalVariableUtils can successfully analyze 'self'. That's required to determine that the assignment
   // of `wrapper` is returned without escaping
-  @lifetime(copy span)
+  @_lifetime(copy span)
   init(span: borrowing Span<T>) {
     self.wrapper = Wrapper(span: span)
   }
diff --git a/test/SILOptimizer/lifetime_dependence/inout.swift b/test/SILOptimizer/lifetime_dependence/inout.swift
index 13f0ad684d453..42916fd6c51b2 100644
--- a/test/SILOptimizer/lifetime_dependence/inout.swift
+++ b/test/SILOptimizer/lifetime_dependence/inout.swift
@@ -3,10 +3,10 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct Span<T>: ~Escapable {
   private var base: UnsafePointer<T>
@@ -18,7 +18,7 @@ struct Span<T>: ~Escapable {
     self.count = count
   }
 
-  @lifetime(borrow generic)
+  @_lifetime(borrow generic)
   init<S>(base: UnsafePointer<T>, count: Int, generic: borrowing S) {
     self.base = base
     self.count = count
@@ -28,7 +28,7 @@ struct Span<T>: ~Escapable {
 struct Wrapper<T: BitwiseCopyable>: ~Escapable {
   private let span: Span<T>
 
-  @lifetime(copy span)
+  @_lifetime(copy span)
   init(span: borrowing Span<T>) {
     self.span = copy span
   }
@@ -42,7 +42,7 @@ struct SuperWrapper<T: BitwiseCopyable>: ~Escapable {
 
   // Make sure that LocalVariableUtils can successfully analyze 'self'. That's required to determine that the assignment
   // of `wrapper` is returned without escaping
-  @lifetime(copy span)
+  @_lifetime(copy span)
   init(span: borrowing Span<T>) {
     self.wrapper = Wrapper(span: span)
   }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_borrow.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_borrow.swift
index a3fbd35c50c60..f9959f638b6d7 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_borrow.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_borrow.swift
@@ -3,10 +3,10 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // Some container-ish thing.
 struct CN: ~Copyable {
@@ -21,7 +21,7 @@ struct BV : ~Escapable {
 
   public var isEmpty: Bool { i == 0 }
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
@@ -38,16 +38,17 @@ struct MBV : ~Escapable, ~Copyable {
   let p: UnsafeRawPointer
   let i: Int
   
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
   }
 
   // Requires a borrow.
-  @lifetime(copy self)
+  @_lifetime(copy self)
   borrowing func getBV() -> BV {
-    BV(p, i)
+    let bv = BV(p, i)
+    return _overrideLifetime(bv, copying: self)
   }
 }
 
@@ -55,32 +56,32 @@ struct MBV : ~Escapable, ~Copyable {
 struct NEBV : ~Escapable {
   var bv: BV
 
-  @lifetime(copy bv)
+  @_lifetime(copy bv)
   init(_ bv: consuming BV) {
     self.bv = bv
   }
 }
 
 // Propagate a borrow.
-@lifetime(copy container)
+@_lifetime(copy container)
 func bv_get_borrow(container: borrowing MBV) -> BV {
   container.getBV()
 }
 
 // Copy a borrow.
-@lifetime(copy container)
+@_lifetime(copy container)
 func bv_get_copy(container: borrowing MBV) -> BV {
   return container.getBV()
 }
 
 // Recognize nested accesses as part of the same dependence scope.
-@lifetime(copy container)
+@_lifetime(copy container)
 func bv_get_mutate(container: inout MBV) -> BV {
   container.getBV()
 }
 
 // Create and decompose a nonescapable aggregate.
-@lifetime(borrow cn)
+@_lifetime(borrow cn)
 func ne_wrap_and_extract_member(cn: borrowing CN) -> BV {
   let bv = BV(cn)
   let ne = NEBV(bv)
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_borrow_fail.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_borrow_fail.swift
index 7878b675e82e9..e52609a31a050 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_borrow_fail.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_borrow_fail.swift
@@ -3,15 +3,15 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct BV : ~Escapable {
   let p: UnsafeRawPointer
   let i: Int
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
@@ -26,7 +26,7 @@ struct NC : ~Copyable {
     self.p = p
     self.i = i
   }
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func getBV() -> BV {
     BV(p, i)
   }
@@ -39,7 +39,7 @@ struct NC : ~Copyable {
 
 // Test dependencies on an empty struct.
 public struct Empty: ~Escapable {
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init() {}
 }
 
@@ -49,18 +49,18 @@ struct NE : ~Escapable {
   let p: UnsafeRawPointer
   let i: Int
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
   }
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func getBV() -> BV {
     BV(p, i)
   }
 }
 
-@lifetime(copy container)
+@_lifetime(copy container)
 func bv_get_consume(container: consuming NE) -> BV {
   return container.getBV() // expected-error {{lifetime-dependent value escapes its scope}}
     // expected-note @-1{{it depends on this scoped access to variable 'container'}}
@@ -71,12 +71,12 @@ struct Wrapper : ~Escapable {
   let bv: BV
 }
 
-@lifetime(copy bv2)
+@_lifetime(copy bv2)
 func bv_incorrect_annotation1(_ bv1: borrowing BV, _ bv2: borrowing BV) -> BV { // expected-error {{lifetime-dependent variable 'bv1' escapes its scope}}
   return copy bv1                                                                              // expected-note @-1{{it depends on the lifetime of argument 'bv1'}}
 }                                                                                              // expected-note @-1{{this use causes the lifetime-dependent value to escape}}
 
-@lifetime(copy w2)
+@_lifetime(copy w2)
 func bv_incorrect_annotation2(_ w1: borrowing Wrapper, _ w2: borrowing Wrapper) -> BV { // expected-error {{lifetime-dependent variable 'w1' escapes its scope}}
   return w1.bv                                                                                        // expected-note @-1{{it depends on the lifetime of argument 'w1'}}
 }                                                                                                     // expected-note @-1{{this use causes the lifetime-dependent value to escape}}
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_closure.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_closure.swift
index 0dbc15d0e2322..bd091f00eec02 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_closure.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_closure.swift
@@ -3,10 +3,10 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct NCInt: ~Copyable {
   var value: Int
@@ -17,7 +17,7 @@ struct NCInt: ~Copyable {
 struct NEInt : ~Escapable {
   let value: Int
 
-  @lifetime(borrow borrowed)
+  @_lifetime(borrow borrowed)
   init(borrowed: borrowing NCInt) {
     self.value = borrowed.value
   }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_coroutine.sil b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_coroutine.sil
new file mode 100644
index 0000000000000..cc2ebd42d17f0
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_coroutine.sil
@@ -0,0 +1,100 @@
+// RUN: %target-sil-opt %s \
+// RUN:   -early-inline \
+// RUN:   -sil-print-types \
+// RUN:   -enable-experimental-feature Lifetimes | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
+
+import Swift
+import Builtin
+
+struct Wrapper : ~Copyable {
+}
+
+struct NE : ~Escapable {
+}
+
+struct MyBox : ~Copyable {
+}
+
+sil @$s4test7WrapperVACycfC : $@convention(method) (@thin Wrapper.Type) -> @owned Wrapper
+sil @$s4test2NEVyAcA7WrapperVhcfC : $@convention(method) (@guaranteed Wrapper, @thin NE.Type) -> @lifetime(borrow 0) @owned NE
+sil @$s4test5MyBoxVACycfC : $@convention(method) (@thin MyBox.Type) -> @owned MyBox
+sil @$s4test3useyyAA2NEVF : $@convention(thin) (@guaranteed NE) -> ()
+
+sil hidden [ossa] @$s4test5MyBoxV5valueAA2NEVvr : $@yield_once @convention(method) (@guaranteed MyBox) -> @lifetime(borrow 0) @yields @guaranteed NE {
+bb0(%0 : @guaranteed $MyBox):
+  %1 = copy_value %0
+  %2 = mark_unresolved_non_copyable_value [no_consume_or_assign] %1
+  %4 = alloc_box ${ let Wrapper }, let, name "w"
+  %5 = begin_borrow [lexical] [var_decl] %4
+  %6 = project_box %5, 0
+  %7 = metatype $@thin Wrapper.Type
+  %8 = function_ref @$s4test7WrapperVACycfC : $@convention(method) (@thin Wrapper.Type) -> @owned Wrapper
+  %9 = apply %8(%7) : $@convention(method) (@thin Wrapper.Type) -> @owned Wrapper
+  store %9 to [init] %6
+  %11 = metatype $@thin NE.Type
+  %12 = mark_unresolved_non_copyable_value [no_consume_or_assign] %6
+  %13 = load_borrow %12
+  %14 = function_ref @$s4test2NEVyAcA7WrapperVhcfC : $@convention(method) (@guaranteed Wrapper, @thin NE.Type) -> @lifetime(borrow 0) @owned NE
+  %15 = apply %14(%13, %11) : $@convention(method) (@guaranteed Wrapper, @thin NE.Type) -> @lifetime(borrow 0) @owned NE
+  %16 = mark_dependence [nonescaping] %15 on %5
+  end_borrow %13
+  yield %16, resume bb1, unwind bb2
+
+bb1:
+  destroy_value %16
+  end_borrow %5
+  destroy_value %4
+  destroy_value %2
+  %23 = tuple ()
+  return %23
+
+bb2:
+  destroy_value %16
+  end_borrow %5
+  destroy_value %4
+  destroy_value %2
+  unwind
+}
+
+// Reduced SIL for validation-test/SILOptimizer/rdar151568816.swift
+
+// CHECK-LABEL: sil hidden [ossa] @$s4test3fooyyF :
+// CHECK:  [[W:%.*]] = alloc_box ${ let Wrapper }, let, name "w"
+// CHECK:  [[B:%.*]] = begin_borrow [lexical] [var_decl] [[W]] : ${ let Wrapper }
+// CHECK:  [[INITFN:%.*]] = function_ref @$s4test2NEVyAcA7WrapperVhcfC : $@convention(method) (@guaranteed Wrapper, @thin NE.Type) -> @lifetime(borrow 0) @owned NE
+// CHECK:  [[NE:%.*]] = apply [[INITFN]]({{.*}}) : $@convention(method) (@guaranteed Wrapper, @thin NE.Type) -> @lifetime(borrow 0) @owned NE
+// CHECK:  [[MDI:%.*]] = mark_dependence [nonescaping] [[NE]] : $NE on [[B]] : ${ let Wrapper }
+// CHECK-LABEL: } // end sil function '$s4test3fooyyF'
+sil hidden [ossa] @$s4test3fooyyF : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_box ${ let MyBox }, let, name "box"
+  %1 = begin_borrow [lexical] [var_decl] %0
+  %2 = project_box %1, 0
+  %3 = metatype $@thin MyBox.Type
+  %4 = function_ref @$s4test5MyBoxVACycfC : $@convention(method) (@thin MyBox.Type) -> @owned MyBox
+  %5 = apply %4(%3) : $@convention(method) (@thin MyBox.Type) -> @owned MyBox
+  store %5 to [init] %2
+  %7 = mark_unresolved_non_copyable_value [no_consume_or_assign] %2
+  %8 = load_borrow %7
+  %9 = function_ref @$s4test5MyBoxV5valueAA2NEVvr : $@yield_once @convention(method) (@guaranteed MyBox) -> @lifetime(borrow 0) @yields @guaranteed NE
+  (%10, %11) = begin_apply %9(%8) : $@yield_once @convention(method) (@guaranteed MyBox) -> @lifetime(borrow 0) @yields @guaranteed NE
+  %12 = mark_dependence [nonescaping] %10 on %11
+  %13 = mark_dependence [nonescaping] %12 on %1
+  %14 = copy_value %13
+  %15 = move_value [var_decl] %14
+  %17 = begin_borrow %15
+  %18 = function_ref @$s4test3useyyAA2NEVF : $@convention(thin) (@guaranteed NE) -> ()
+  %19 = apply %18(%17) : $@convention(thin) (@guaranteed NE) -> ()
+  end_borrow %17
+  destroy_value %15
+  %22 = end_apply %11 as $()
+  end_borrow %8
+  end_borrow %1
+  destroy_value %0
+  %26 = tuple ()
+  return %26
+}
+
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_diagnostics.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_diagnostics.swift
index e161fa38707c7..a5c1981322301 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_diagnostics.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_diagnostics.swift
@@ -1,23 +1,23 @@
 // RUN: %target-swift-frontend %s -Xllvm -sil-print-types -emit-sil \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   2>&1 | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct BV : ~Escapable {
   let p: UnsafeRawPointer
   let c: Int
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ c: Int) {
     self.p = p
     self.c = c
   }
 }
 
-@lifetime(copy bv)
+@_lifetime(copy bv)
 func bv_copy(_ bv: borrowing BV) -> BV {
   copy bv
 }
@@ -30,20 +30,20 @@ public struct NEInt: ~Escapable {
   var i: Int
 
   // Test yielding an address.
-  // CHECK-LABEL: sil hidden @$s4test5NEIntV5iprop{{.*}}vM : $@yield_once @convention(method) (@inout NEInt) -> @lifetime(borrow 0) @yields @inout NEInt
+  // CHECK-LABEL: sil hidden @$s4test5NEIntV5iprop{{.*}}vM : $@yield_once @convention(method) (@lifetime(copy 0) @inout NEInt) -> @lifetime(borrow 0) @yields @inout NEInt
   // CHECK: bb0(%0 : $*NEInt):
   // CHECK: [[A:%.*]] = begin_access [modify] [static] %0 : $*NEInt
   // CHECK: yield [[A]] : $*NEInt, resume bb1, unwind bb2
   // CHECK: end_access [[A]] : $*NEInt
   // CHECK: end_access [[A]] : $*NEInt
   var iprop: NEInt {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read { yield self }
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify { yield &self }
   }
 
-  @lifetime(borrow owner)
+  @_lifetime(borrow owner)
   init(owner: borrowing NCInt) {
     self.i = owner.i
   }
@@ -56,7 +56,7 @@ public enum NEOptional<Wrapped: ~Escapable>: ~Escapable {
 
 extension NEOptional where Wrapped: ~Escapable {
   // Test that enum initialization passes diagnostics.
-  @lifetime(copy some)
+  @_lifetime(copy some)
   public init(_ some: consuming Wrapped) { self = .some(some) }
 }
 
@@ -69,7 +69,7 @@ func takeClosure(_: () -> ()) {}
 // CHECK:        apply %{{.*}}(%0) : $@convention(thin) (@guaranteed BV) -> @lifetime(copy 0) @owned BV
 // CHECK-NEXT:   return %3 : $BV
 // CHECK-LABEL: } // end sil function '$s4test14bv_borrow_copyyAA2BVVADF'
-@lifetime(borrow bv)
+@_lifetime(borrow bv)
 func bv_borrow_copy(_ bv: borrowing BV) -> BV {
   bv_copy(bv) 
 }
@@ -83,7 +83,7 @@ func bv_borrow_copy(_ bv: borrowing BV) -> BV {
 // CHECK:         %{{.*}} = mark_dependence [nonescaping] [[R]] : $BV on %0 : $BV
 // CHECK-NEXT:    return %{{.*}} : $BV
 // CHECK-LABEL: } // end sil function '$s4test010bv_borrow_C00B0AA2BVVAE_tF'
-@lifetime(borrow bv)
+@_lifetime(borrow bv)
 func bv_borrow_borrow(bv: borrowing BV) -> BV {
   bv_borrow_copy(bv)
 }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_enums.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_enums.swift
new file mode 100644
index 0000000000000..e18762d00eaf1
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_enums.swift
@@ -0,0 +1,34 @@
+// RUN: %target-swift-frontend %s -emit-sil \
+// RUN:   -sil-verify-all | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+
+public protocol OptionalType<Wrapped> {
+  associatedtype Wrapped
+
+  static func some(_ wrapped: Wrapped) -> Self
+  static func somePair(_ wrapped1: Wrapped, _ wrapped2: Wrapped) -> Self
+  static func esc(_ e: E) -> Self
+}
+
+public struct E {}
+
+public enum FakeOptional<Wrapped : ~Escapable & ~Copyable> : ~Escapable & ~Copyable {
+  case none
+  case some(Wrapped)
+  case somePair(Wrapped, Wrapped)
+  case esc(E)
+}
+
+extension FakeOptional: Copyable where Wrapped: Copyable & ~Escapable {}
+
+extension FakeOptional: Escapable where Wrapped: Escapable & ~Copyable {}
+
+extension FakeOptional : OptionalType {}
+
+// CHECK-LABEL: sil shared [transparent] @$s25lifetime_dependence_enums12FakeOptionalO4someyACyxGxcAEmlF : $@convention(method) <Wrapped where Wrapped : ~Copyable, Wrapped : ~Escapable> (@in Wrapped, @thin FakeOptional<Wrapped>.Type) -> @lifetime(copy 0) @out FakeOptional<Wrapped> {
+
+// CHECK-LABEL: sil shared [transparent] @$s25lifetime_dependence_enums12FakeOptionalO8somePairyACyxGx_xtcAEmlF : $@convention(method) <Wrapped where Wrapped : ~Copyable, Wrapped : ~Escapable> (@in Wrapped, @in Wrapped, @thin FakeOptional<Wrapped>.Type) -> @lifetime(copy 0, copy 1) @out FakeOptional<Wrapped> {
+
+// CHECK-LABEL: sil shared [transparent] @$s25lifetime_dependence_enums12FakeOptionalO3escyACyxGAA1EVcAEmlF : $@convention(method) <Wrapped where Wrapped : ~Copyable, Wrapped : ~Escapable> (E, @thin FakeOptional<Wrapped>.Type) -> @out FakeOptional<Wrapped> {
+
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_generic.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_generic.swift
index b4fb8f6ccedfb..e0c45037c0780 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_generic.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_generic.swift
@@ -2,12 +2,12 @@
 // RUN:   -o /dev/null \
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-feature SuppressedAssociatedTypes \
 // RUN:   -parse-stdlib -module-name Swift
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_SuppressedAssociatedTypes
 
 @_marker public protocol Escapable {}
@@ -19,12 +19,12 @@ precedencegroup AssignmentPrecedence { assignment: true }
 
 protocol P {
   associatedtype E: ~Escapable
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func getE() -> E
 }
 
 extension P {
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func getDefault() -> E {
     return getE()
   }
@@ -52,29 +52,29 @@ struct NCInt: ~Copyable {
 struct NEInt: ~Escapable {
   let value: Builtin.Int64
 
-  @lifetime(copy o)
+  @_lifetime(copy o)
   init<O: ~Copyable & ~Escapable>(v: Builtin.Int64, o: borrowing O) {
     self.value = v
   }
 
   // Test a generic storage owner.
-  @lifetime(borrow borrowed)
+  @_lifetime(borrow borrowed)
   init(borrowed: borrowing NCInt) {
     self.init(v: borrowed.value, o: borrowed)
   }
 }
 
-@lifetime(copy ne)
+@_lifetime(copy ne)
 public func consume_indirect<NE: ~Escapable>(ne: consuming NE) -> NE {
   return ne
 }
 
-@lifetime(copy ne)
+@_lifetime(copy ne)
 public func copy_indirect<NE: ~Escapable>(ne: borrowing NE) -> NE {
   return copy ne
 }
 
-@lifetime(copy ne)
+@_lifetime(copy ne)
 public func copy_inout<NE: ~Escapable>(ne: inout NE) -> NE {
   return copy ne
 }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_inherit.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_inherit.swift
index 04c2c95600965..501eea8be0614 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_inherit.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_inherit.swift
@@ -3,15 +3,15 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence should be expressed by a builtin that is
 // hidden within the function body.
 @_unsafeNonescapableResult
-@lifetime(copy source)
+@_lifetime(copy source)
 func unsafeLifetime<T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable>(
   dependent: consuming T, dependsOn source: borrowing U)
   -> T {
@@ -22,19 +22,19 @@ struct BV : ~Escapable {
   let p: UnsafeRawPointer
   let i: Int
  
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
   }
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(independent p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
   }
 
-  @lifetime(copy self)
+  @_lifetime(copy self)
   consuming func derive() -> BV {
     // Technically, this "new" view does not depend on the 'view' argument.
     // This unsafely creates a new view with no dependence.
@@ -48,41 +48,41 @@ struct NEBV : ~Escapable {
   var bv: BV
 
   // Test lifetime inheritance through initialization.
-  @lifetime(copy bv)
+  @_lifetime(copy bv)
   init(_ bv: consuming BV) {
     self.bv = bv
   }
 
   var view: BV {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield bv
     }
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &bv
     }
   }
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   func borrowedView() -> BV {
     bv
   }
 }
 
 // Test lifetime inheritance through chained consumes.
-@lifetime(copy bv)
+@_lifetime(copy bv)
 func bv_derive(bv: consuming BV) -> BV {
   bv.derive()
 }
 
 // Test lifetime inheritance through stored properties.
-@lifetime(copy nebv)
+@_lifetime(copy nebv)
 func ne_extract_member(nebv: consuming NEBV) -> BV {
   return nebv.bv
 }
 
-@lifetime(copy nebv)
+@_lifetime(copy nebv)
 func ne_yield_member(nebv: consuming NEBV) -> BV {
   return nebv.view
 }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_inherit_fail.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_inherit_fail.swift
index fa22ab268c9ea..53208e14aa592 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_inherit_fail.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_inherit_fail.swift
@@ -3,15 +3,15 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence should be expressed by a builtin that is
 // hidden within the function body.
 @_unsafeNonescapableResult
-@lifetime(copy source)
+@_lifetime(copy source)
 func unsafeLifetime<T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable>(
   dependent: consuming T, dependsOn source: borrowing U)
   -> T {
@@ -22,19 +22,19 @@ struct BV : ~Escapable {
   let p: UnsafeRawPointer
   let i: Int
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
   }
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(independent p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
   }
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   consuming func derive() -> BV {
     // Technically, this "new" view does not depend on the 'view' argument.
     // This unsafely creates a new view with no dependence.
@@ -46,7 +46,7 @@ struct BV : ~Escapable {
 struct NE : ~Escapable {
   var bv: BV
 
-  @lifetime(copy bv)
+  @_lifetime(copy bv)
   init(_ bv: consuming BV) {
     self.bv = bv
   }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_insertion.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_insertion.swift
index a34dbc2461b16..bb2bef719611f 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_insertion.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_insertion.swift
@@ -2,17 +2,17 @@
 // RUN:   -Xllvm -sil-print-types -Xllvm -sil-print-after=lifetime-dependence-insertion \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -o /dev/null 2>&1 | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct BV : ~Escapable {
   let p: UnsafeRawPointer
   let i: Int
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
@@ -24,7 +24,7 @@ struct NC : ~Copyable {
   let i: Int
 
   // Requires a borrow.
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func getBV() -> BV {
     BV(p, i)
   }
@@ -59,7 +59,7 @@ func bv_borrow_var(p: UnsafeRawPointer, i: Int) {
 // CHECK: [[MD:%.*]] = mark_dependence [unresolved] [[BV]] : $BV on %0 : $UnsafePointer<Int>
 // CHECK: return [[MD]] : $BV
 // CHECK-LABEL: } // end sil function '$s4test18bv_pointer_convert1pAA2BVVSPySiG_tF'
-@lifetime(borrow p)
+@_lifetime(borrow p)
 func bv_pointer_convert(p: UnsafePointer<Int>) -> BV {
   BV(p, 0)
 }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_mutate.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_mutate.swift
index b1b28f35b416a..c64ba289b7cd7 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_mutate.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_mutate.swift
@@ -3,58 +3,16 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
-
-/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
-/// a value identical to `dependent` with a lifetime dependency on the caller's
-/// borrow scope of the `source` argument.
-@_unsafeNonescapableResult
-@_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, borrowing source: borrowing U
-) -> T {
-  dependent
-}
-
-/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
-/// a value identical to `dependent` that inherits all lifetime dependencies from
-/// the `source` argument.
-@_unsafeNonescapableResult
-@_transparent
-@lifetime(copy source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, copying source: borrowing U
-) -> T {
-  dependent
-}
-
-/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
-/// a value identical to `dependent` that inherits all lifetime dependencies from
-/// the `source` argument.
-@_unsafeNonescapableResult
-@_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, mutating source: inout U
-) -> T {
-  dependent
-}
+// REQUIRES: swift_feature_Lifetimes
 
 struct MutableSpan : ~Escapable, ~Copyable {
   let base: UnsafeMutableRawPointer
   let count: Int
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeMutableRawPointer, _ c: Int) {
     self.base = p
     self.count = c
@@ -76,7 +34,7 @@ struct MutableSpan : ~Escapable, ~Copyable {
     var base: UnsafeMutableRawPointer
     var count: Int
 
-    @lifetime(borrow base)
+    @_lifetime(borrow base)
     init(base: UnsafeMutableRawPointer, count: Int) {
       self.base = base
       self.count = count
@@ -92,8 +50,11 @@ struct MutableSpan : ~Escapable, ~Copyable {
   }
 
   var iterator: Iter {
-    @lifetime(copy self)
-    get { Iter(base: base, count: count) }
+    @_lifetime(copy self)
+    get {
+      let newIter = Iter(base: base, count: count)
+      return _overrideLifetime(newIter, copying: self)
+    }
   }
 }
 
@@ -112,7 +73,7 @@ struct NC : ~Copyable {
   let c: Int
 
   // Requires a mutable borrow.
-  @lifetime(borrow self)
+  @_lifetime(&self)
   mutating func getMutableSpan() -> MutableSpan {
     MutableSpan(p, c)
   }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_optional.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_optional.swift
index 291c4421eebf4..75b98c679b6eb 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_optional.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_optional.swift
@@ -2,15 +2,15 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // Simply test that it is possible for a module to define a pseudo-Optional type without triggering any compiler errors.
 
 public protocol ExpressibleByNilLiteral: ~Copyable & ~Escapable {
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init(nilLiteral: ()) 
 }
 
@@ -30,7 +30,7 @@ extension Nillable: BitwiseCopyable where Wrapped: BitwiseCopyable { }
 
 extension Nillable: ExpressibleByNilLiteral where Wrapped: ~Copyable & ~Escapable {
   @_transparent
-  @lifetime(immortal)
+  @_lifetime(immortal)
   public init(nilLiteral: ()) {
     self = .none
   }
@@ -38,7 +38,7 @@ extension Nillable: ExpressibleByNilLiteral where Wrapped: ~Copyable & ~Escapabl
 
 extension Nillable where Wrapped: ~Copyable & ~Escapable {
   @_transparent
-  @lifetime(copy some)
+  @_lifetime(copy some)
   public init(_ some: consuming Wrapped) { self = .some(some) }
 }
 
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_param.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_param.swift
index 3299545d1146c..a4826001c7a0e 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_param.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_param.swift
@@ -3,15 +3,15 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence should be expressed by a builtin that is
 // hidden within the function body.
 @_unsafeNonescapableResult
-@lifetime(copy source)
+@_lifetime(copy source)
 func unsafeLifetime<T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable>(
   dependent: consuming T, dependsOn source: borrowing U)
   -> T {
@@ -22,13 +22,13 @@ struct BV : ~Escapable {
   let p: UnsafeRawPointer
   let i: Int
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
   }
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(independent p: UnsafeRawPointer, _ i: Int) {
     self.p = p
     self.i = i
@@ -38,7 +38,7 @@ struct BV : ~Escapable {
   public var isEmpty: Bool { i == 0 }
 
   // Test consuming `self`
-  @lifetime(copy self)
+  @_lifetime(copy self)
   consuming func derive() -> BV {
     // Technically, this "new" view does not depend on the 'view' argument.
     // This unsafely creates a new view with no dependence.
@@ -51,7 +51,7 @@ struct BV : ~Escapable {
 struct NE {
   var bv: BV
 
-  @lifetime(copy bv)
+  @_lifetime(copy bv)
   init(_ bv: BV) {
     self.bv = bv
   }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_param_fail.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_param_fail.swift
index 30608bf43840d..dc12135660ae4 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_param_fail.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_param_fail.swift
@@ -3,16 +3,16 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct BV : ~Escapable {
   let p: UnsafeRawPointer
   let c: Int
 
-  @lifetime(borrow p)
+  @_lifetime(borrow p)
   init(_ p: UnsafeRawPointer, _ c: Int) {
     self.p = p
     self.c = c
@@ -33,45 +33,45 @@ struct NC : ~Copyable {
 struct NE {
   var bv: BV
 
-  @lifetime(copy bv)
+  @_lifetime(copy bv)
   init(_ bv: consuming BV) {
     self.bv = bv
   }
 }
 
-@lifetime(other: copy bv)
+@_lifetime(other: copy bv)
 func bv_assign_inout_copy(bv: BV, other: inout BV) {
   other = bv // OK
 }
 
-@lifetime(other: borrow bv)
+@_lifetime(other: borrow bv)
 func bv_assign_inout_borrow(bv: BV, other: inout BV) {
   other = bv
 }
 
-@lifetime(bv: copy bv)
-@lifetime(other: copy bv)
+@_lifetime(bv: copy bv)
+@_lifetime(other: copy bv)
 func bvmut_assign_inout(bv: inout BV, other: inout BV) {
   other = bv
 }
 
-@lifetime(other: copy bv)
+@_lifetime(other: copy bv)
 func bvcons_assign_inout(bv: consuming BV, other: inout BV) {
   other = bv
 }
 
-@lifetime(other: copy bv)
+@_lifetime(other: copy bv)
 func bv_assign_field(bv: BV, other: inout NE) {
   other.bv = bv
 }
 
-@lifetime(bv: copy bv)
-@lifetime(other: copy bv)
+@_lifetime(bv: copy bv)
+@_lifetime(other: copy bv)
 func bvmut_assign_field(bv: inout BV, other: inout NE) {
   other.bv = bv
 }
 
-@lifetime(other: copy bv)
+@_lifetime(other: copy bv)
 func bvcons_assign_field(bv: consuming BV, other: inout NE) {
   other.bv = bv
 }
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_scope_fixup.swift b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_scope_fixup.swift
index cbcf3ff5789d5..900998edb52b3 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_scope_fixup.swift
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_scope_fixup.swift
@@ -1,9 +1,23 @@
-// RUN: %target-swift-frontend %s -Xllvm -sil-print-types -emit-sil \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: %target-swift-frontend %s -Xllvm -sil-print-types -Xllvm -sil-disable-pass=onone-simplification -emit-sil \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
+
+/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
+/// a value identical to `dependent` that inherits all lifetime dependencies from
+/// the `source` argument.
+@_unsafeNonescapableResult
+@_transparent
+@_lifetime(copy source)
+internal func _overrideLifetime<
+  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
+>(
+  _ dependent: consuming T, copying source: borrowing U
+) -> T {
+  dependent
+}
 
 struct NCContainer : ~Copyable {
   let ptr: UnsafeRawBufferPointer
@@ -17,12 +31,12 @@ struct NCContainer : ~Copyable {
 struct View : ~Escapable {
   let ptr: UnsafeRawBufferPointer
   let c: Int
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(_ ptr: UnsafeRawBufferPointer, _ c: Int) {
     self.ptr = ptr
     self.c = c
   }
-  @lifetime(copy otherBV)
+  @_lifetime(copy otherBV)
   init(_ otherBV: borrowing View) {
     self.ptr = otherBV.ptr
     self.c = otherBV.c
@@ -33,50 +47,63 @@ struct View : ~Escapable {
   }
   // This overload requires a separate label because overloading
   // on borrowing/consuming attributes is not allowed
-  @lifetime(copy k)
+  @_lifetime(copy k)
   init(consumingView k: consuming View) {
     self.ptr = k.ptr
     self.c = k.c
   }
 }
 
-struct MutableView : ~Copyable, ~Escapable {
-  let ptr: UnsafeRawBufferPointer
+struct NCMutableContainer : ~Copyable {
+  let ptr: UnsafeMutableRawBufferPointer
   let c: Int
-  @lifetime(borrow ptr)
-  init(_ ptr: UnsafeRawBufferPointer, _ c: Int) {
+  init(_ ptr: UnsafeMutableRawBufferPointer, _ c: Int) {
     self.ptr = ptr
     self.c = c
   }
-  @lifetime(copy otherBV)
-  init(_ otherBV: borrowing View) {
+}
+
+struct MutableView : ~Copyable, ~Escapable {
+  let ptr: UnsafeMutableRawBufferPointer
+  @_lifetime(borrow ptr)
+  init(_ ptr: UnsafeMutableRawBufferPointer) {
+    self.ptr = ptr
+  }
+  @_lifetime(copy otherBV)
+  init(_ otherBV: borrowing MutableView) {
     self.ptr = otherBV.ptr
-    self.c = otherBV.c
   }
-  init(_ k: borrowing NCContainer) {
+  init(_ k: borrowing NCMutableContainer) {
     self.ptr = k.ptr
-    self.c = k.c
+  }
+}
+
+extension MutableView {
+  @_lifetime(&self)
+  mutating public func update() -> Self {
+    return unsafe MutableView(ptr)
   }
 }
 
 func use(_ o : borrowing View) {}
 func mutate(_ x: inout NCContainer) { }
+func mutate(_ x: inout NCMutableContainer) { }
 func mutate(_ x: inout View) { }
 func consume(_ o : consuming View) {}
 func use(_ o : borrowing MutableView) {}
 func consume(_ o : consuming MutableView) {}
 
-@lifetime(copy x)
+@_lifetime(copy x)
 func getConsumingView(_ x: consuming View) -> View {
   return View(consumingView: x)
 }
 
-@lifetime(borrow x)
+@_lifetime(borrow x)
 func getBorrowingView(_ x: borrowing View) -> View {
   return View(x.ptr, x.c)
 }
 
-@lifetime(borrow x)
+@_lifetime(borrow x)
 func getBorrowingView(_ x: borrowing NCContainer) -> View {
   return View(x.ptr, x.c)
 }
@@ -125,9 +152,9 @@ func test3(_ a: Array<Int>) {
   }
 }
 
-func test4(_ a: Array<Int>) {
-  a.withUnsafeBytes {
-    var x = NCContainer($0, a.count)
+func test4(_ a: inout Array<Int>) {
+  a.withUnsafeMutableBytes {
+    var x = NCMutableContainer($0, $0.count)
     mutate(&x)
     let view = MutableView(x)
     use(view)
@@ -180,11 +207,11 @@ func test7(_ a: UnsafeRawBufferPointer) {
   mutate(&x)
 }
 
-func test8(_ a: Array<Int>) {
-  a.withUnsafeBytes {
-    var x = View($0, a.count)
+func test8(_ a: inout Array<Int>) {
+  a.withUnsafeMutableBytes {
+    var x = View(UnsafeRawBufferPointer(start: $0.baseAddress!, count: $0.count), $0.count)
     mutate(&x)
-    let view = MutableView(x)
+    let view = MutableView($0)
     use(view)
     consume(view)
   }
@@ -193,16 +220,16 @@ func test8(_ a: Array<Int>) {
 struct Wrapper : ~Escapable {
   var _view: View
   var view: View {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield _view
     }
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &_view
     }
   }
-  @lifetime(copy view)
+  @_lifetime(copy view)
   init(_ view: consuming View) {
     self._view = view
   }
@@ -218,9 +245,11 @@ func test9() {
   }
 }
 
-@lifetime(copy x)
+@_lifetime(copy x)
 func getViewTuple(_ x: borrowing View) -> (View, View) {
-  return (View(x.ptr, x.c), View(x.ptr, x.c))
+  let x1 = View(x.ptr, x.c)
+  let x2 = View(x.ptr, x.c)
+  return (_overrideLifetime(x1, copying: x), _overrideLifetime(x2, copying: x))
 }
 
 public func test10() {
@@ -245,3 +274,66 @@ func testPointeeDependenceOnMutablePointer(p: UnsafePointer<Int64>) {
   _ = ptr.pointee
   _ = ptr
 }
+
+// CHECK-LABEL: sil hidden @$s31lifetime_dependence_scope_fixup16testReassignment1bySw_tF : $@convention(thin) (UnsafeMutableRawBufferPointer) -> () {
+// CHECK: bb0(%0 : $UnsafeMutableRawBufferPointer):
+// CHECK:   [[VAR:%.*]] = alloc_stack [lexical] [var_decl] $MutableView, var, name "span", type $MutableView
+// CHECK:   apply %{{.*}}(%0, %{{.*}}) : $@convention(method) (UnsafeMutableRawBufferPointer, @thin MutableView.Type) -> @lifetime(borrow 0) @owned MutableView
+// CHECK:   [[ACCESS1:%.*]] = begin_access [modify] [static] [[VAR]] : $*MutableView
+// CHECK:   apply %{{.*}}(%{{.*}}) : $@convention(method) (@lifetime(copy 0) @inout MutableView) -> @lifetime(borrow 0) @owned MutableView
+// CHECK:   [[LD1:%.*]] = load %{{.*}} : $*MutableView
+// CHECK:   apply %{{.*}}([[LD1]]) : $@convention(thin) (@guaranteed MutableView) -> ()
+// CHECK:   end_access [[ACCESS1]] : $*MutableView
+// CHECK:   [[ACCESS2:%.*]] = begin_access [modify] [static] [[VAR]] : $*MutableView
+// CHECK:   apply %{{.*}}(%{{.*}}) : $@convention(method) (@lifetime(copy 0) @inout MutableView) -> @lifetime(borrow 0) @owned MutableView
+// CHECK:   [[LD2:%.*]] = load %{{.*}} : $*MutableView
+// CHECK:   apply %{{.*}}([[LD2]]) : $@convention(thin) (@guaranteed MutableView) -> ()
+// CHECK:   end_access [[ACCESS2]] : $*MutableView
+// CHECK:   destroy_addr [[VAR]] : $*MutableView
+// CHECK-LABEL: } // end sil function '$s31lifetime_dependence_scope_fixup16testReassignment1bySw_tF'
+func testReassignment(b: UnsafeMutableRawBufferPointer) {
+  var span = MutableView(b)
+
+  var sub = span.update()
+  use(sub)
+
+  sub = span.update()
+  use(sub)
+}
+
+
+// Coroutine nested in a mutable access scope.
+//
+// rdar://150275147 (Invalid SIL after lifetime dependence fixup involving coroutines)
+struct ArrayWrapper {
+  private var a: [Int]
+
+  var array: [Int] {
+    _read {
+      yield a
+    }
+    _modify {
+      yield &a
+    }
+  }
+}
+
+@_silgen_name("gms")
+func getMutableSpan(_: inout [Int]) -> MutableSpan<Int>
+
+func testWrite(_ w: inout ArrayWrapper) {
+  var span = getMutableSpan(&w.array)
+  for i in span.indices {
+    span[i] = 0
+  }
+}
+
+// Test store_borrow extension which is required when the addressable UTF8View is extended over the Span's uses.
+//
+// UTF8Span is unavailable on watchOS as of the introduction of this test.
+@available(watchOS, unavailable)
+@available(SwiftStdlib 6.2, *)
+func testSpanOfBorrowByAddress(_ i: Int) -> Int {
+    let span = String(i).utf8.span
+    return span.count
+}
diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_util.sil b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_util.sil
index 5436b6d3c5a5f..e582f211c3685 100644
--- a/test/SILOptimizer/lifetime_dependence/lifetime_dependence_util.sil
+++ b/test/SILOptimizer/lifetime_dependence/lifetime_dependence_util.sil
@@ -6,7 +6,7 @@
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
 
-sil_stage canonical
+sil_stage raw
 
 import Builtin
 
@@ -92,6 +92,34 @@ entry(%0 : @owned $C):
   return %99 : $()
 }
 
+sil hidden [ossa] @testRootForTemp : $@convention(thin) () -> () {
+bb0:
+  %varC = alloc_box ${ var C }, var, name "ne"
+  %borrowC = begin_borrow [lexical] [var_decl] %varC
+  %addrC = project_box %borrowC, 0
+
+  %finit = function_ref @getC : $@convention(thin) () -> @owned C
+  %newC = apply %finit() : $@convention(thin) () -> @owned C
+  store %newC to [init] %addrC
+
+  %accessC = begin_access [read] [unknown] %addrC
+  %tempC = load [copy] %accessC
+  end_access %accessC
+  specify_test "lifetime_dependence_root %tempC"
+// CHECK-LABEL: testRootForTemp: lifetime_dependence_root with: %tempC
+// CHECK: Lifetime dependence roots of: {{%.*}} = load [copy] %{{.*}} : $*C
+// CHECK: root: %{{.*}} = begin_access [read] [unknown] %{{.*}} : $*C
+// CHECK-LABEL: end running test 1 of 1 on testRootForTemp: lifetime_dependence_root with: %tempC
+
+  destroy_value %tempC
+
+  end_borrow %borrowC
+  destroy_value %varC
+
+  %99 = tuple ()
+  return %99
+}
+
 sil [ossa] @dependence_scope : $@convention(thin) (@owned C, @owned D, @guaranteed D, @in_guaranteed D, @inout D) -> () {
 entry(%0 : @owned $C, %1 : @owned $D, %2 : @guaranteed $D, %3 : $*D, %4 : $*D):
   %move = move_value %1 : $D
@@ -224,6 +252,7 @@ bb0(%0 : @guaranteed $NE):
 
 // CHECK-LABEL: dependence_coroutine: lifetime_dependence_use with: %0
 // CHECK: LifetimeDependence uses of: %0 = argument of bb0 : $NE
+// CHECK-NEXT: Leaf use: operand #0 of   destroy_value %{{.*}} : $NE
 // CHECK-NEXT: Leaf use: operand #0 of   %{{.*}} = end_apply %{{.*}} as $()
 // CHECK-NEXT: dependence_coroutine: lifetime_dependence_use with: %0
 sil [ossa] @dependence_coroutine : $@convention(thin) (@guaranteed NE) -> () {
diff --git a/test/SILOptimizer/lifetime_dependence/local_var_util.sil b/test/SILOptimizer/lifetime_dependence/local_var_util.sil
new file mode 100644
index 0000000000000..3215b3770ad3d
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/local_var_util.sil
@@ -0,0 +1,134 @@
+// RUN: %target-sil-opt -test-runner %s \
+// RUN:     -enable-experimental-feature LifetimeDependence \
+// RUN:     -o /dev/null 2>&1 | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_LifetimeDependence
+
+sil_stage raw
+
+import Builtin
+import Swift
+import SwiftShims
+
+struct NE: ~Escapable {}
+
+sil @makeDepNE : $@convention(thin) (@inout NE) -> @lifetime(borrow address_for_deps 0) @out NE
+
+// CHECK-LABEL: testNEInitNoEscape: local_variable_reachable_uses with: %1, @instruction
+// CHECK: ### Access map:
+// CHECK-NEXT: Access map for:   %{{.*}} = alloc_box ${ var NE }, var, name "self"
+// CHECK-NEXT: assign: true, store  destroy_value %{{.*}} : ${ var NE }
+// CHECK-NEXT: assign: false, escape  %{{.*}} = address_to_pointer %{{.*}} : $*NE to $Builtin.RawPointer
+// CHECK-NEXT: assign: true, beginAccess  %{{.*}} = begin_access [modify] [unknown] %{{.*}} : $*NE
+// CHECK-NEXT: assign: false, load  %{{.*}} = load [copy] %{{.*}} : $*NE
+// CHECK-NEXT: assign: true, beginAccess  %{{.*}} = begin_access [modify] [unknown] %{{.*}} : $*NE
+// CHECK-NEXT: ### Modify:   %{{.*}} = begin_access [modify] [unknown] %4 : $*NE
+// CHECK-NEXT: ### Reachable access:
+// CHECK-NEXT: load  %{{.*}} = load [copy] %{{.*}} : $*NE
+// CHECK-NEXT: testNEInitNoEscape: local_variable_reachable_uses with: %1, @instruction
+
+// CHECK-LABEL: testNEInitNoEscape: local_variable_reaching_assignments with: %1, @instruction
+// CHECK: ### Instruction:   end_access %{{.*}} : $*NE
+// CHECK-NEXT: ### Reachable assignments:
+// CHECK-NEXT: beginAccess  %21 = begin_access [modify] [unknown] %4 : $*NE
+// CHECK-NEXT: testNEInitNoEscape: local_variable_reaching_assignments with: %1, @instruction
+sil [ossa] @testNEInitNoEscape : $@convention(thin) (@inout NE) -> @lifetime(borrow 0) @owned NE {
+bb0(%0 : $*NE):
+  %1 = alloc_box ${ var NE }, var, name "self"
+  %2 = mark_uninitialized [rootself] %1
+  %3 = begin_borrow [lexical] [var_decl] %2
+  %4 = project_box %3, 0
+  cond_br undef, bb1, bb2
+
+bb1:
+  br bb3
+
+bb2:
+  br bb3
+
+bb3:
+  %8 = alloc_stack $NE
+
+  %9 = begin_access [modify] [unknown] %0
+
+  %10 = function_ref @makeDepNE : $@convention(thin) (@inout NE) -> @lifetime(borrow address_for_deps 0) @out NE
+  %11 = apply %10(%8, %9) : $@convention(thin) (@inout NE) -> @lifetime(borrow address_for_deps 0) @out NE
+
+  mark_dependence_addr [unresolved] %8 on %9
+  end_access %9
+
+  %14 = load [take] %8
+
+  specify_test "local_variable_reachable_uses %1 @instruction"
+  %15 = begin_access [modify] [unknown] %4
+  assign %14 to %15
+  end_access %15
+  dealloc_stack %8
+  %19 = load [copy] %4
+
+  %21 = load [take] %8
+  %22 = begin_access [modify] [unknown] %4
+  assign %21 to %22
+  specify_test "local_variable_reaching_assignments %1 @instruction"
+  end_access %22
+  %escape = address_to_pointer %4 : $*NE to $Builtin.RawPointer
+  end_borrow %3
+  destroy_value %2
+  return %19
+}
+
+// CHECK-LABEL: testNEInitEscape: local_variable_reaching_assignments with: %1, @instruction
+// CHECK: ### Instruction:   %{{.*}} = load [take] %{{.*}} : $*NE
+// CHECK-NEXT: !!! Reaching escape
+// CHECK-NEXT: testNEInitEscape: local_variable_reaching_assignments with: %1, @instruction
+
+// CHECK-LABEL: testNEInitEscape: local_variable_reachable_uses with: %1, @instruction
+// CHECK: ### Access map:
+// CHECK-NEXT: Access map for:   %{{.*}} = alloc_box ${ var NE }, var, name "self"
+// CHECK-NEXT: assign: true, store  destroy_value %{{.*}} : ${ var NE }
+// CHECK-NEXT: assign: false, load  %{{.*}} = load [copy] %{{.*}} : $*NE
+// CHECK-NEXT: assign: true, beginAccess  %{{.*}} = begin_access [modify] [unknown] %{{.*}} : $*NE
+// CHECK-NEXT: assign: false, escape  %6 = address_to_pointer %4 : $*NE to $Builtin.RawPointer
+// CHECK-NEXT: ### Modify:   %{{.*}} = begin_access [modify] [unknown] %4 : $*NE
+// CHECK-NEXT: !!! Reachable escape
+// CHECK-NEXT: testNEInitEscape: local_variable_reachable_uses with: %1, @instruction
+sil [ossa] @testNEInitEscape : $@convention(thin) (@inout NE) -> @lifetime(borrow 0) @owned NE {
+bb0(%0 : $*NE):
+  %1 = alloc_box ${ var NE }, var, name "self"
+  %2 = mark_uninitialized [rootself] %1
+  %3 = begin_borrow [lexical] [var_decl] %2
+  %4 = project_box %3, 0
+  cond_br undef, bb1, bb2
+
+bb1:
+  %escape = address_to_pointer %4 : $*NE to $Builtin.RawPointer
+  br bb3
+
+bb2:
+  br bb3
+
+bb3:
+  %8 = alloc_stack $NE
+
+  %9 = begin_access [modify] [unknown] %0
+
+  %10 = function_ref @makeDepNE : $@convention(thin) (@inout NE) -> @lifetime(borrow address_for_deps 0) @out NE
+  %11 = apply %10(%8, %9) : $@convention(thin) (@inout NE) -> @lifetime(borrow address_for_deps 0) @out NE
+
+  mark_dependence_addr [unresolved] %8 on %9
+  end_access %9
+
+  specify_test "local_variable_reaching_assignments %1 @instruction"
+  %14 = load [take] %8
+
+  specify_test "local_variable_reachable_uses %1 @instruction"
+  %15 = begin_access [modify] [unknown] %4
+  assign %14 to %15
+  end_access %15
+  dealloc_stack %8
+  %19 = load [copy] %4
+  end_borrow %3
+  destroy_value %2
+  return %19
+}
diff --git a/test/SILOptimizer/lifetime_dependence/projections.swift b/test/SILOptimizer/lifetime_dependence/projections.swift
new file mode 100644
index 0000000000000..07d3ad27eac00
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/projections.swift
@@ -0,0 +1,194 @@
+// RUN: %target-swift-frontend %s -emit-sil \
+// RUN:   -o /dev/null \
+// RUN:   -verify \
+// RUN:   -sil-verify-all \
+// RUN:   -enable-builtin-module \
+// RUN:   -module-name test \
+// RUN:   -enable-experimental-feature Lifetimes \
+// RUN:   -enable-experimental-feature AddressableTypes \
+// RUN:   -enable-experimental-feature AddressableParameters
+
+// RUN: %target-swift-frontend %s -emit-silgen \
+// RUN:   -sil-verify-all \
+// RUN:   -enable-builtin-module \
+// RUN:   -module-name test \
+// RUN:   -enable-experimental-feature Lifetimes \
+// RUN:   -enable-experimental-feature AddressableTypes \
+// RUN:   -enable-experimental-feature AddressableParameters \
+// RUN:   2>&1 | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_AddressableTypes
+// REQUIRES: swift_feature_AddressableParameters
+
+import Builtin
+
+class C {
+  var p: Builtin.RawPointer
+  init(p: Builtin.RawPointer) { self.p = p }
+
+  // unsupported annotation
+  @_addressableSelf
+  func method() {}
+}
+
+struct NE: ~Escapable {
+  var p: Builtin.RawPointer
+}
+
+struct PtrHolder {
+  var field: Builtin.RawPointer
+}
+
+struct CHolder {
+  var field: C
+}
+
+struct IHolder {
+  var field: Int
+}
+
+@_lifetime(borrow ptr)
+func depends(onPtr ptr: Builtin.RawPointer) -> NE {
+  NE(p: ptr)
+}
+
+// FIXME: Allowed now, but should be prohibited if projection dependence carries exclusivity.
+// rdar://153670930 ([nonescapable] extend access scopes for trivial value (UnsafePointer) dependencies)
+@_lifetime(&holder)
+func testTrivialField(holder: inout PtrHolder, other: Builtin.RawPointer) -> NE {
+  // copy holder.field
+  // end_access holder.field
+  let ne = depends(onPtr: holder.field)
+  // mark_dependence ne on holder
+  holder.field = other
+  return ne
+}
+
+@_lifetime(borrow c)
+func depends(onC c: C) -> NE {
+  let ne = NE(p: c.p)
+  return _overrideLifetime(ne, borrowing: c)
+}
+
+// OK: Correctly diagnoses the exclusivity violation.
+@_lifetime(&holder)
+func testObjectField(holder: inout CHolder, other: C) -> NE {
+  // copy holder.field
+  // end_access holder.field
+  let ne = depends(onC: holder.field) // expected-note{{conflicting access is here}}
+  // mark_dependence ne on holder
+  holder.field = other // expected-error{{overlapping accesses to 'holder.field', but modification requires exclusive access; consider copying to a local variable}}
+  return ne
+}
+
+// OK
+@_lifetime(&holder)
+func testAddress(holder: inout IHolder) -> NE {
+  // Requires rdar://137608270 ([borrows] Add Builtin.addressof() support for @addressable arguments)
+  depends(onPtr: Builtin.addressOfBorrow(holder))
+}
+
+@_lifetime(borrow i)
+func depends(onInt i: @_addressable Int) -> NE {
+  NE(p: Builtin.addressOfBorrow(i))
+}
+
+// OK: no escape diagnostic because the addressable dependency is on the parameter address.
+@_lifetime(&holder)
+func testAddressableTrivialField(holder: inout IHolder) -> NE{
+  // load holder.field
+  // end_access holder.field
+  // alloc_stack Int
+  // store
+  return depends(onInt: holder.field)
+  // mark_dependence on alloc_stack
+  // (the addressable dependence needs to be on the passed-in address)
+}
+
+@_lifetime(borrow x)
+func depends(onCAddress x: @_addressable C) -> NE {
+  let ne = NE(p: x.p)
+  return _overrideLifetime(ne, borrowing: x)
+}
+
+// OK: no escape diagnostic because the addressable dependency is on the parameter address.
+@_lifetime(&holder)
+func testAddressableObjectField(holder: inout CHolder) -> NE {
+  // tmp = load [copy] holder.field
+  // end_access holder.field
+  // alloc_stack
+  // store tmp
+  return depends(onCAddress: holder.field)
+  // mark_dependence ne on alloc_stack
+}
+
+// Copyable to test the absence of temporaries.
+@_addressableForDependencies
+struct Cell<T> {
+  var t: T
+}
+
+struct CellHolder: ~Copyable {
+  var field: Cell<Int>
+}
+
+@_lifetime(borrow x)
+func depends(onCell x: borrowing Cell<Int>) -> NE {
+  NE(p: Builtin.addressOfBorrow(x))
+}
+
+// OK: no escape diagnostic because the addressable dependency is on the parameter address.
+@_lifetime(&holder)
+func testAddressableType(holder: inout CellHolder) -> NE {
+  // tmp = load [copy] holder.field
+  // end_access holder.field
+  // alloc_stack
+  // store tmp
+  return depends(onCell: holder.field)
+  // mark_dependence ne on alloc_stack
+}
+
+/* FIXME: Invalid SIL: rdar://152273896 (SILGen: @_addressableSelf support for class methods)
+func testAddressableClass(c: C) {
+  c.method()
+}
+*/
+
+struct Object {
+  var c: C
+
+  @_addressableSelf
+  func method() {}
+}
+
+struct UniquePointer<T>: ~Copyable {
+  var _p: UnsafePointer<T>
+
+  var value: T { unsafeAddress { _p } }
+}
+
+// No copy allowed. A copy would be invalid when class 'C' is imported from C++.
+//
+// CHECK-LABEL: sil hidden [ossa] @$s4test0A15AddressableSelf2upyAA13UniquePointerVyAA6ObjectVG_tF : $@convention(thin) (@guaranteed UniquePointer<Object>) -> () {
+// CHECK: bb0(%0 : @guaranteed $UniquePointer<Object>):
+// CHECK:   [[CP:%[0-9]+]] = copy_value %0
+// CHECK:   [[MNC:%[0-9]+]] = mark_unresolved_non_copyable_value [no_consume_or_assign] [[CP]]
+// CHECK:   [[BB:%[0-9]+]] = begin_borrow [[MNC]]
+// CHECK:   [[PTR:%[0-9]+]] = struct_extract %{{.*}}, #UnsafePointer._rawValue
+// CHECK:   [[ADR:%[0-9]+]] = pointer_to_address [[PTR]] to [strict] $*Object
+// CHECK:   [[MD:%[0-9]+]] = mark_dependence [unresolved] [[ADR]] on [[BB]]
+// CHECK-NOT: load
+// CHECK-NOT: alloc_stack
+// CHECK-NOT: store
+// CHECK:   apply %{{.*}}([[MD]]) : $@convention(method) (@in_guaranteed Object) -> ()
+// CHECK-LABEL: } // end sil function '$s4test0A15AddressableSelf2upyAA13UniquePointerVyAA6ObjectVG_tF'
+func testAddressableSelf(up: borrowing UniquePointer<Object>) {
+  // tmp = load [copy] up.value
+  // end_access up.value
+  // alloc_stack
+  // store tmp
+  // apply method(tmp)
+  up.value.method()
+}
diff --git a/test/SILOptimizer/lifetime_dependence/scope_fixup.sil b/test/SILOptimizer/lifetime_dependence/scope_fixup.sil
index 4637f0fe8dec7..b99577312abb8 100644
--- a/test/SILOptimizer/lifetime_dependence/scope_fixup.sil
+++ b/test/SILOptimizer/lifetime_dependence/scope_fixup.sil
@@ -1,13 +1,13 @@
 // RUN: %target-sil-opt \
 // RUN:   -lifetime-dependence-scope-fixup \
 // RUN:   -sil-verify-all \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-feature AddressableParameters \
 // RUN:   -enable-experimental-feature AddressableTypes \
 // RUN:   %s | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_AddressableParameters
 // REQUIRES: swift_feature_AddressableTypes
 
@@ -21,7 +21,7 @@ import Swift
 struct NE : ~Escapable {
   var p: UnsafeRawPointer
 
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init()
 }
 
@@ -39,10 +39,27 @@ struct NCContainer : ~Copyable {
   var wrapper: Wrapper { get } // _read
 }
 
+struct NCWrapper : ~Copyable, ~Escapable {
+  @_hasStorage let a: NE { get }
+  deinit
+}
+
+sil @NCWrapper_getNE : $@convention(method) (@guaranteed NCWrapper) -> @lifetime(borrow 0) @owned NE
+
 struct TrivialHolder {
   var pointer: UnsafeRawPointer
 }
 
+struct A {
+  init()
+}
+
+struct B: ~Copyable, ~Escapable {
+  let ne: NE
+
+  deinit
+}
+
 struct Holder {
   var object: AnyObject
 }
@@ -50,15 +67,86 @@ struct Holder {
 @_addressableForDependencies
 struct AddressableForDeps {}
 
+@_addressableForDependencies
+struct AddressableForDepsObj {
+  var object: AnyObject
+}
+
+public struct MutableView : ~Copyable, ~Escapable {
+  @_hasStorage var ptr: UnsafeMutableRawBufferPointer { get set }
+  init(ptr: UnsafeMutableRawBufferPointer)
+}
+
+public struct Container : ~Escapable, ~Copyable {
+  @_hasStorage var somethings: UnsafeMutableRawBufferPointer { get set }
+  init(somethings: UnsafeMutableRawBufferPointer)
+}
+
+public struct AThing : ~Copyable {
+  @_hasStorage var somethings: UnsafeMutableRawBufferPointer { get set }
+  init(somethings: UnsafeMutableRawBufferPointer)
+}
+
+@_addressableForDependencies
+public struct InlineInt {
+  var i: Int
+}
+
+sil @getContainer : $@convention(thin) (@inout AThing) -> @lifetime(borrow address_for_deps 0) @out Container
+sil @getMutableView : $@convention(thin) (@in_guaranteed Container) -> @lifetime(copy 0) @out Optional<MutableView>
+sil @modAThing : $@convention(thin) (@inout AThing) -> ()
+sil @getSpan : $@convention(thin) (@inout MutableView) -> @lifetime(borrow address_for_deps 0) @owned MutableRawSpan
+
+sil @getNEPointerToA : $@convention(thin) (@guaranteed NE) -> UnsafePointer<A>
+sil @useA : $@convention(thin) (A) -> ()
+sil @useAAddr : $@convention(thin) (@in A) -> ()
+
 sil @getPtr : $@convention(thin) () -> @out UnsafeRawPointer
-sil @getSpan : $@convention(thin) (@in_guaranteed AnyObject) -> @lifetime(borrow 0) @out NE
+
+sil @getOwnedNE : $@convention(thin) (@guaranteed Holder) -> @lifetime(borrow 0) @owned NE
+sil @getOwnedNEFromInout : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @owned NE
 
 sil @useNE : $@convention(thin) (@guaranteed NE) -> ()
 
 sil [ossa] @Wrapper_init : $@convention(method) (@owned NE, @thin Wrapper.Type) -> @lifetime(copy 0) @owned Wrapper
 
+sil @yieldWrapper : $@yield_once @convention(method) (@guaranteed NCContainer) -> @lifetime(borrow 0) @yields @guaranteed Wrapper
+sil @yieldNE : $@yield_once @convention(method) (@guaranteed Wrapper) -> @lifetime(copy 0) @yields @guaranteed NE
+
 sil [ossa] @NCContainer_ne_read : $@yield_once @convention(method) (@guaranteed NCContainer) -> @lifetime(borrow 0) @yields @guaranteed NE
 
+sil @yieldRawSpan : $@yield_once @convention(method) (@in_guaranteed A) -> @lifetime(borrow address_for_deps 0) @yields @guaranteed RawSpan
+sil @useRawSpan : $@convention(thin) (@guaranteed RawSpan) -> ()
+
+sil @initHolder : $@convention(method) (@thin Holder.Type) -> @owned Holder
+sil @readAccess : $@yield_once @convention(method) (@guaranteed Holder) -> @lifetime(borrow 0) @yields @guaranteed NE
+
+sil @yieldInoutHolder : $@yield_once @convention(method) (@inout Holder) -> @yields @inout Holder
+sil @yieldInoutNE : $@yield_once @convention(method) (@inout Holder) -> @lifetime(borrow 0) @owned NE
+
+class C {
+  @_hasStorage @_hasInitialValue private var nc: NCWrapper? { get set }
+}
+
+sil @C_read : $@yield_once @convention(method) (@guaranteed C) -> @yields @guaranteed Optional<NCWrapper>
+
+struct S {
+  let c: C
+}
+struct MutNE: ~Copyable & ~Escapable {}
+
+sil @getMutNE : $@convention(thin) (@inout S) -> @lifetime(borrow 0) @owned MutNE
+
+sil @getHolder : $@convention(thin) () -> @owned Holder
+
+sil @getAddressableObj : $@convention(method) (@guaranteed Holder) -> @owned AddressableForDepsObj
+
+sil @getAddressableObj_NE : $@convention(thin) (@in_guaranteed AddressableForDepsObj) -> @owned NE
+
+sil @globalAddress : $@convention(thin) () -> Builtin.RawPointer
+sil @addressInt : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address_for_deps 0) @owned Span<Int>
+sil @useSpan : $@convention(thin) (@guaranteed Span<Int>) -> ()
+
 // NCContainer.wrapper._read:
 //   var wrapper: Wrapper {
 //     _read {
@@ -163,9 +251,9 @@ sil [ossa] @addressableArg : $@convention(thin) (@in_guaranteed Holder) -> @life
 // CHECK: apply %{{.*}}([[MV]]) : $@convention(thin) (@guaranteed NE) -> ()
 // CHECK: destroy_value [[MV]]
 // CHECK: end_borrow [[SB]]
+// CHECK: dealloc_stack [[ALLOC]]
 // CHECK: end_borrow [[BORROWB]]
 // CHECK: end_borrow [[BORROWA]]
-// CHECK: dealloc_stack [[ALLOC]]
 // CHECK-LABEL: } // end sil function 'testAddressableArg'
 sil hidden [ossa] @testAddressableArg : $@convention(thin) (@guaranteed Holder) -> () {
 bb0(%0 : @guaranteed $Holder):
@@ -191,6 +279,44 @@ bb0(%0 : @guaranteed $Holder):
   return %99 : $()
 }
 
+// Extend a store_borrow with a small allocation range.
+//
+// CHECK-LABEL: sil hidden [ossa] @testSmallStoreBorrow : $@convention(thin) (@guaranteed Holder) -> () {
+// CHECK: bb0(%0 : @guaranteed $Holder):
+// CHECK: [[BORROWA:%.*]] = begin_borrow %0
+// CHECK: [[ALLOC:%.*]] = alloc_stack $Holder
+// CHECK: [[SB:%.*]] = store_borrow [[BORROWA]] to [[ALLOC]]
+// CHECK: [[APPLY:%.*]] = apply %{{.*}}([[SB]]) : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address 0) @owned NE
+// CHECK: [[MD:%.*]] = mark_dependence [unresolved] [[APPLY]] on [[SB]]
+// CHECK: [[MV:%.*]] = move_value [var_decl] [[MD]]
+// CHECK: apply %{{.*}}([[MV]]) : $@convention(thin) (@guaranteed NE) -> ()
+// CHECK: destroy_value [[MV]]
+// CHECK: end_borrow [[SB]]
+// CHECK: dealloc_stack [[ALLOC]]
+// CHECK: end_borrow [[BORROWA]]
+// CHECK-LABEL: } // end sil function 'testSmallStoreBorrow'
+sil hidden [ossa] @testSmallStoreBorrow : $@convention(thin) (@guaranteed Holder) -> () {
+bb0(%0 : @guaranteed $Holder):
+  debug_value %0, let, name "arg", argno 1
+  %borrow0a = begin_borrow %0 : $Holder
+  // store-borrow
+  %sballoc = alloc_stack $Holder
+  %sb = store_borrow %borrow0a to %sballoc
+  %fdep = function_ref @addressableArg : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address 0) @owned NE
+  %ne = apply %fdep(%sb) : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address 0) @owned NE
+  %nedep = mark_dependence [unresolved] %ne on %sb
+  end_borrow %sb
+  dealloc_stack %sballoc
+  end_borrow %borrow0a : $Holder
+  %nevar = move_value [var_decl] %nedep
+  debug_value %nevar, let, name "ne"
+  %fuse = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %user = apply %fuse(%nevar) : $@convention(thin) (@guaranteed NE) -> ()
+  destroy_value %nevar
+  %99 = tuple ()
+  return %99 : $()
+}
+
 // CHECK-LABEL: sil hidden [ossa] @testIndirectYield : $@convention(thin) (@guaranteed Holder) -> () {
 // CHECK: bb0(%0 : @guaranteed $Holder):
 // CHECK: [[BORROW0A:%.*]] = begin_borrow %0
@@ -237,3 +363,610 @@ bb0(%0 : @guaranteed $Holder):
   %99 = tuple ()
   return %99 : $()
 }
+
+// FIXME: extend temporary lifetimes for coroutine access.
+//
+// CHECK-LABEL: sil [ossa] @testYieldSpan : $@convention(thin) (@in A) -> () {
+// CHECK:   alloc_stack [lexical] [var_decl] $A
+// CHECK:   (%{{.*}}, %{{.*}}) = begin_apply %{{.*}}(%{{.*}}) : $@yield_once @convention(method) (@in_guaranteed A) -> @lifetime(borrow address_for_deps 0) @yields @guaranteed RawSpan
+// CHECK:   [[MD:%.*]] = mark_dependence [unresolved]
+// CHECK:   [[CP:%.*]] = copy_value [[MD]]
+// CHECK:   apply %{{.*}}([[CP]]) : $@convention(thin) (@guaranteed RawSpan) -> ()
+// CHECK:   destroy_value [[CP]]
+// CHECK:   end_apply
+// CHECK:   destroy_addr
+// CHECK-LABEL: } // end sil function 'testYieldSpan'
+sil [ossa] @testYieldSpan : $@convention(thin) (@in A) -> () {
+bb0(%0 : $*A):
+  %1 = alloc_stack [lexical] [var_decl] $A
+  copy_addr [take] %0 to [init] %1
+
+  %3 = function_ref @yieldRawSpan : $@yield_once @convention(method) (@in_guaranteed A) -> @lifetime(borrow address_for_deps 0) @yields @guaranteed RawSpan
+  (%4, %5) = begin_apply %3(%1) : $@yield_once @convention(method) (@in_guaranteed A) -> @lifetime(borrow address_for_deps 0) @yields @guaranteed RawSpan
+  %6 = mark_dependence [unresolved] %4 on %5
+  %7 = copy_value %6
+  %8 = end_apply %5 as $()
+
+  %9 = function_ref @useRawSpan : $@convention(thin) (@guaranteed RawSpan) -> ()
+  %10 = apply %9(%7) : $@convention(thin) (@guaranteed RawSpan) -> ()
+  destroy_value %7
+  destroy_addr %1
+  dealloc_stack %1
+  %14 = tuple ()
+  return %14
+}
+
+// =============================================================================
+// Owned value extension
+// =============================================================================
+
+// Handle direct _read accessor. Extend the coroutine scope and extend the lifetime of the coroutine's guaranteed
+// argument.
+//
+// CHECK-LABEL: sil hidden [ossa] @testNestedCoro : $@convention(thin) () -> () {
+// CHECK: [[SPAN:%.*]] = alloc_box ${ var NE }, var, name "span"
+// CHECK: [[BORROW:%.*]] = begin_borrow [var_decl] [[SPAN]]
+// CHECK: [[A1:%.*]] = begin_access [read] [unknown] %2
+// CHECK: [[LD:%.*]] = load [copy] [[A1]]
+// CHECK: end_access [[A1]]
+// CHECK: (%{{.*}}, [[TOKEN:%.*]]) = begin_apply %13([[LD]]) : $@yield_once @convention(method) (@guaranteed Holder) -> @lifetime(borrow 0) @yields @guaranteed NE
+// CHECK: ignored_use [[DEP:%[0-9]+]]
+// CHECK: destroy_value [[DEP]]
+// CHECK: end_apply [[TOKEN]] as $()
+// CHECK: destroy_value [[LD]]
+// CHECK: end_borrow [[BORROW]]
+// CHECK-LABEL: } // end sil function 'testNestedCoro'
+sil hidden [ossa] @testNestedCoro : $@convention(thin) () -> () {
+bb0:
+  %varH = alloc_box ${ var Holder }, var, name "h"
+  %borrowH = begin_borrow [lexical] [var_decl] %varH
+  %addrH = project_box %borrowH, 0
+  %metaH = metatype $@thin Holder.Type
+
+  %finit = function_ref @initHolder : $@convention(method) (@thin Holder.Type) -> @owned Holder
+  %newH = apply %finit(%metaH) : $@convention(method) (@thin Holder.Type) -> @owned Holder
+  store %newH to [init] %addrH
+
+  %varSpan = alloc_box ${ var NE }, var, name "span"
+  %borrowSpan = begin_borrow [var_decl] %varSpan
+  %addrSpan = project_box %borrowSpan, 0
+
+  %accessH = begin_access [read] [unknown] %addrH
+  %tempH = load [copy] %accessH
+  end_access %accessH
+
+  %fread = function_ref @readAccess : $@yield_once @convention(method) (@guaranteed Holder) -> @lifetime(borrow 0) @yields @guaranteed NE
+  (%yieldSpan, %token) = begin_apply %fread(%tempH) : $@yield_once @convention(method) (@guaranteed Holder) -> @lifetime(borrow 0) @yields @guaranteed NE
+  %depSpan = mark_dependence [unresolved] %yieldSpan on %token
+  %copySpan = copy_value %depSpan
+  %endCoro = end_apply %token as $()
+  destroy_value %tempH
+
+  store %copySpan to [init] %addrSpan
+  %accessSpan = begin_access [read] [unknown] %addrSpan
+  %span = load [copy] %accessSpan
+  end_access %accessSpan
+  ignored_use %span
+  destroy_value %span
+
+  end_borrow %borrowSpan
+  destroy_value %varSpan
+
+  end_borrow %borrowH
+  destroy_value %varH
+
+  %99 = tuple ()
+  return %99
+}
+
+// =============================================================================
+// Coroutine extension
+// =============================================================================
+
+// Sink the inner end_apply and the outer end_access.
+//
+// CHECK-LABEL: sil hidden [ossa] @testCoroutineInsideAccess : $@convention(thin) (@inout Holder) -> () {
+// CHECK: bb0(%0 : $*Holder):
+// CHECK: [[BORROW:%[0-9]+]] = begin_borrow [lexical] [var_decl]
+// CHECK: [[ACCESS:%[0-9]+]] = begin_access [modify] [unknown] %0
+// CHECK: ({{.*}}, [[TOKEN:%[0-9]+]]) = begin_apply %{{.*}}([[ACCESS]]) : $@yield_once @convention(method) (@inout Holder) -> @yields @inout Holder
+// CHECK: apply
+// CHECK: [[MD:%[0-9]+]] = mark_dependence [unresolved] %10 on %7
+// CHECK: apply
+// CHECK: end_borrow
+// CHECK: end_access
+// CHECK: end_apply [[TOKEN]] as $()
+// CHECK: end_access [[ACCESS]]
+// CHECK: end_borrow [[BORROW]]
+// CHECK-LABEL: } // end sil function 'testCoroutineInsideAccess'
+sil hidden [ossa] @testCoroutineInsideAccess : $@convention(thin) (@inout Holder) -> () {// %0 "w"
+bb0(%0 : $*Holder):
+  debug_value %0, var, name "w", argno 1, expr op_deref
+  %2 = alloc_box ${ var NE }, var, name "span"
+  %3 = begin_borrow [lexical] [var_decl] %2
+  %4 = project_box %3, 0
+  %5 = begin_access [modify] [unknown] %0
+  %6 = function_ref @yieldInoutHolder : $@yield_once @convention(method) (@inout Holder) -> @yields @inout Holder
+  (%7, %8) = begin_apply %6(%5) : $@yield_once @convention(method) (@inout Holder) -> @yields @inout Holder
+  %9 = function_ref @getOwnedNEFromInout : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @owned NE
+  %10 = apply %9(%7) : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @owned NE
+  %11 = mark_dependence [unresolved] %10 on %7
+  %12 = end_apply %8 as $()
+  end_access %5
+  store %11 to [init] %4
+  %15 = begin_access [read] [unknown] %4
+  %16 = load_borrow [unchecked] %15
+  %17 = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %18 = apply %17(%16) : $@convention(thin) (@guaranteed NE) -> ()
+  end_borrow %16
+  end_access %15
+  end_borrow %3
+  destroy_value %2
+  %99 = tuple ()
+  return %99
+}
+
+// Test a nested dependent coroutine. The inner coroutine yields a
+// value (NE) that inherits its dependency from the outer yield
+// (Wrapper). All copies of the inner yield must be used within the
+// scope of the outer coroutine. The outer end_apply must be extended
+// below the call to 'useNE'.
+//
+// CHECK-LABEL: sil hidden [ossa] @testCopiedYield : $@convention(thin) (@owned NCContainer) -> () {
+// CHECK: bb0(%0 : @owned $NCContainer):
+// CHECK:   [[BOX:%[0-9]+]] = alloc_box ${ var NCContainer }, var, name "nc"
+// CHECK:   [[ACCESS:%[0-9]+]] = begin_access [read] [unknown]
+// CHECK:   [[LB:%[0-9]+]] = load_borrow [unchecked]
+// CHECK:   ([[YIELD:%[0-9]+]], [[TOKEN:%[0-9]+]]) = begin_apply %7(%6) : $@yield_once @convention(method) (@guaranteed NCContainer) -> @lifetime(borrow 0) @yields @guaranteed Wrapper
+// CHECK:   mark_dependence [unresolved] [[YIELD]] on [[TOKEN]]
+// CHECK:   ([[NE:%[0-9]+]], %{{.*}}) = begin_apply %13(%12) : $@yield_once @convention(method) (@guaranteed Wrapper) -> @lifetime(copy 0) @yields @guaranteed NE
+// CHECK:   destroy_value
+// CHECK:   apply %{{.*}}(%{{.*}}) : $@convention(thin) (@guaranteed NE) -> ()
+// CHECK:   destroy_value %{{.*}}
+// CHECK:   end_apply [[TOKEN]] as $()
+// CHECK:   end_borrow [[LB]]
+// CHECK:   end_access [[ACCESS]]
+// CHECK:   destroy_value [[BOX]]
+// CHECK-LABEL: } // end sil function 'testCopiedYield'
+sil hidden [ossa] @testCopiedYield : $@convention(thin) (@owned NCContainer) -> () {
+bb0(%0 : @owned $NCContainer):
+  %1 = alloc_box ${ var NCContainer }, var, name "nc"
+  %2 = begin_borrow [lexical] [var_decl] %1
+  %3 = project_box %2, 0
+  store %0 to [init] %3
+  %5 = begin_access [read] [unknown] %3
+  %7 = load_borrow [unchecked] %5
+
+  %8 = function_ref @yieldWrapper : $@yield_once @convention(method) (@guaranteed NCContainer) -> @lifetime(borrow 0) @yields @guaranteed Wrapper
+  (%9, %10) = begin_apply %8(%7) : $@yield_once @convention(method) (@guaranteed NCContainer) -> @lifetime(borrow 0) @yields @guaranteed Wrapper
+  %11 = mark_dependence [unresolved] %9 on %10
+  %12 = copy_value %11
+  %13 = end_apply %10 as $()
+  end_borrow %7
+  end_access %5
+  %16 = move_value [var_decl] %12
+
+  %18 = function_ref @yieldNE : $@yield_once @convention(method) (@guaranteed Wrapper) -> @lifetime(copy 0) @yields @guaranteed NE
+  (%19, %20) = begin_apply %18(%16) : $@yield_once @convention(method) (@guaranteed Wrapper) -> @lifetime(copy 0) @yields @guaranteed NE
+  %21 = copy_value %19
+  %22 = end_apply %20 as $()
+  destroy_value %16
+  %23 = move_value [var_decl] %21
+
+  %25 = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %26 = apply %25(%23) : $@convention(thin) (@guaranteed NE) -> ()
+  destroy_value %23
+  end_borrow %2
+  destroy_value %1
+  %31 = tuple ()
+  return %31
+}
+
+// rdar://153479358 (Compiler crash when force-unwrapping optional ~Copyable type)
+//
+// Handle dead end coroutines: begin_apply -> end_borrow
+// CHECK-LABEL: sil hidden [ossa] @testReadDeadEnd : $@convention(method) (@guaranteed C) -> () {
+// CHECK: bb0(%0 : @guaranteed $C):
+// CHECK:   ({{.*}}, [[TOKEN:%[0-9]+]]) = begin_apply %{{.*}}(%0) : $@yield_once @convention(method) (@guaranteed C) -> @yields @guaranteed Optional<NCWrapper>
+// CHECK:   switch_enum %{{.*}}, case #Optional.some!enumelt: bb2, case #Optional.none!enumelt: bb1
+// CHECK: bb1:
+// CHECK:   destroy_value [dead_end]
+// CHECK:   end_borrow [[TOKEN]]
+// CHECK:   unreachable
+// CHECK: bb2(%{{.*}} : @guaranteed $NCWrapper):
+// CHECK:   mark_dependence [unresolved]
+// CHECK:   destroy_value
+// CHECK:   destroy_value
+// CHECK:   end_apply [[TOKEN]] as $()
+// CHECK-LABEL: } // end sil function 'testReadDeadEnd'
+sil hidden [ossa] @testReadDeadEnd : $@convention(method) (@guaranteed C) -> () {
+bb0(%0 : @guaranteed $C):
+  // FIXME: I don't know how to print a lifetime-dependent class method in SIL.
+  // %2 = class_method %0, #C.nc!read : (C) -> () -> (), $@yield_once @convention(method) (@guaranteed C) -> @yields @guaranteed Optional<NCWrapper>
+  %2 = function_ref @C_read : $@yield_once @convention(method) (@guaranteed C) -> @yields @guaranteed Optional<NCWrapper>
+  (%3, %4) = begin_apply %2(%0) : $@yield_once @convention(method) (@guaranteed C) -> @yields @guaranteed Optional<NCWrapper>
+  %5 = copy_value %3
+  %6 = mark_unresolved_non_copyable_value [no_consume_or_assign] %5
+  %7 = alloc_stack $Optional<NCWrapper>
+  %8 = mark_unresolved_non_copyable_value [no_consume_or_assign] %7
+  %9 = store_borrow %6 to %8
+  %10 = load_borrow [unchecked] %9
+  switch_enum %10, case #Optional.some!enumelt: bb2, case #Optional.none!enumelt: bb1
+
+bb1:
+  end_borrow %10
+  end_borrow %9
+  destroy_value [dead_end] %6
+  end_borrow %4
+  unreachable
+
+bb2(%25 : @guaranteed $NCWrapper):
+  %26 = function_ref @NCWrapper_getNE : $@convention(method) (@guaranteed NCWrapper) -> @lifetime(borrow 0) @owned NE
+  %27 = apply %26(%25) : $@convention(method) (@guaranteed NCWrapper) -> @lifetime(borrow 0) @owned NE
+  %28 = mark_dependence [unresolved] %27 on %3
+  end_borrow %10
+  end_borrow %9
+  destroy_value %6
+  %32 = end_apply %4 as $()
+  dealloc_stack %7
+  %34 = move_value [var_decl] %28
+  destroy_value %34
+  %37 = tuple ()
+  return %37
+}
+
+// =============================================================================
+// Return value extension
+// =============================================================================
+
+// Sink the end access to the "return" phi and rewrite mark_dependence on the argument.
+//
+// CHECK-LABEL: sil hidden [ossa] @testReturnPhi : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @owned Optional<NE> {
+// CHECK: bb0(%0 : $*Holder):
+// CHECK: bb1:
+// CHECK:   enum $Optional<NE>, #Optional.none!enumelt
+// CHECK: bb2:
+// CHECK:   [[ACCESS:%.*]] = begin_access [modify] [unknown] %0
+// CHECK:   [[MD:%.*]] = mark_dependence [unresolved] {{%.*}} on %0
+// CHECK:   [[OPT:%.*]] = enum $Optional<NE>, #Optional.some!enumelt, %7
+// CHECK:   end_access [[ACCESS]]
+// CHECK:   br bb3([[OPT]])
+// CHECK: bb3([[RET:%.*]] : @owned $Optional<NE>):
+// CHECK:   return [[RET]]
+// CHECK-LABEL: } // end sil function 'testReturnPhi'
+sil hidden [ossa] @testReturnPhi : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @owned Optional<NE> {
+bb0(%0 : $*Holder):
+  cond_br undef, bb1, bb2
+
+bb1:
+  %none = enum $Optional<NE>, #Optional.none!enumelt
+  br bb3(%none)
+
+bb2:
+  %access = begin_access [modify] [unknown] %0
+  %f = function_ref @getOwnedNEFromInout : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @owned NE
+  %ne = apply %f(%access) : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @owned NE
+  %md = mark_dependence [unresolved] %ne on %access
+  end_access %access
+  %some = enum $Optional<NE>, #Optional.some!enumelt, %md
+  br bb3(%some)
+
+bb3(%ret : @owned $Optional<NE>):
+  return %ret
+}
+
+// Allow a [read] access to depend on a caller's [modify] access.
+//
+// CHECK-LABEL: sil hidden [noinline] [ossa] @testNestedModRead : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @owned NE {
+// CHECK: bb0(%0 : $*Holder):
+// CHECK:   [[ACCESS:%.*]] = begin_access [read] [unknown] %0
+// CHECK:   [[LD:%.*]] = load [copy] [[ACCESS]]
+// CHECK:   [[MD:%.*]] = mark_dependence [unresolved] %{{.*}} on %0
+// CHECK:   destroy_value [[LD]]
+// CHECK:   end_access [[ACCESS]]
+// CHECK:   return [[MD]]
+// CHECK-LABEL: } // end sil function 'testNestedModRead'
+sil hidden [noinline] [ossa] @testNestedModRead : $@convention(thin) (@inout Holder) -> @lifetime(borrow 0) @owned NE {
+bb0(%0 : $*Holder):
+  %access = begin_access [read] [unknown] %0
+  %holder = load [copy] %access
+  end_access %access
+  %f = function_ref @getOwnedNE : $@convention(thin) (@guaranteed Holder) -> @lifetime(borrow 0) @owned NE
+  %ne = apply %f(%holder) : $@convention(thin) (@guaranteed Holder) -> @lifetime(borrow 0) @owned NE
+  %md = mark_dependence [unresolved] %ne on %access
+  destroy_value %holder
+  return %md
+}
+
+// =============================================================================
+// alloc_stack extension
+// =============================================================================
+
+// Test alloc_stack extension around a store_borrow.
+//
+// CHECK-LABEL: sil hidden [ossa] @testStoreBorrowAlloc : $@convention(thin) () -> () {
+// CHECK:   [[OBJ:%[0-9]+]] = apply %{{.*}}(%{{.*}}) : $@convention(method) (@guaranteed Holder) -> @owned AddressableForDepsObj
+// CHECK:   [[ALLOC:%[0-9]+]] = alloc_stack $AddressableForDepsObj
+// CHECK:   [[SB:%[0-9]+]] = store_borrow %{{.*}} to [[ALLOC]]
+// CHECK:   [[MV:%[0-9]+]] = move_value [var_decl]
+// CHECK:   [[TEMP:%[0-9]+]] = alloc_stack $A
+// CHECK:   apply %{{.*}}([[TEMP]]) : $@convention(thin) (@in A) -> ()
+// CHECK:   destroy_value [[MV]]
+// CHECK:   end_borrow [[SB]]
+// CHECK:   destroy_value 
+// CHECK:   dealloc_stack [[TEMP]]
+// CHECK:   dealloc_stack [[ALLOC]]
+// CHECK-LABEL: } // end sil function 'testStoreBorrowAlloc'
+sil hidden [ossa] @testStoreBorrowAlloc : $@convention(thin) () -> () {
+bb0:
+  %5 = function_ref @getHolder : $@convention(thin) () -> @owned Holder
+  %6 = apply %5() : $@convention(thin) () -> @owned Holder
+
+  %8 = function_ref @getAddressableObj : $@convention(method) (@guaranteed Holder) -> @owned AddressableForDepsObj
+  %9 = apply %8(%6) : $@convention(method) (@guaranteed Holder) -> @owned AddressableForDepsObj
+  destroy_value %6
+  %alloc1 = alloc_stack $AddressableForDepsObj
+  %12 = store_borrow %9 to %alloc1
+
+  %13 = function_ref @getAddressableObj_NE : $@convention(thin) (@in_guaranteed AddressableForDepsObj) -> @owned NE
+  %14 = apply %13(%12) : $@convention(thin) (@in_guaranteed AddressableForDepsObj) -> @owned NE
+  %15 = mark_dependence [unresolved] %14 on %12
+  %16 = move_value [var_decl] %15
+  end_borrow %12
+  dealloc_stack %alloc1
+  destroy_value %9
+
+  %tempA = alloc_stack $A
+  store undef to [trivial] %tempA
+  %f = function_ref @useAAddr : $@convention(thin) (@in A) -> ()
+  %v = apply %f(%tempA) : $@convention(thin) (@in A) -> ()
+
+  %21 = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %22 = apply %21(%16) : $@convention(thin) (@guaranteed NE) -> ()
+  destroy_value %16
+
+  // dealloc_stack %alloc1 is initially inserted here and needs to be corrected by fixStackNesting.
+  dealloc_stack %tempA
+
+  %99 = tuple ()
+  return %99 : $()
+}
+
+// =============================================================================
+// Reduced bugs
+// =============================================================================
+
+// rdar149226564 (Compiler crash with non-escapable storing another non-escapable and having a deinit)
+//
+// Test that initializing LifetimeDependence.Scope from an unidentified enclosing access scope does not
+// unwrap nil.
+//
+// CHECK-LABEL: sil hidden [ossa] @testUnidentified : $@convention(method) (@owned B) -> () {
+// CHECK: [[AS:%.*]] = alloc_stack $B
+// CHECK: [[MU:%.*]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[AS]]
+// CHECK: [[DD:%.*]] = drop_deinit [[MU]]
+// CHECK: [[SE:%.*]] = struct_element_addr [[DD]], #B.ne
+// CHECK: [[LB:%.*]] = load_borrow
+// CHECK: apply %{{.*}} : $@convention(thin) (@guaranteed NE) -> UnsafePointer<A>
+// CHECK: mark_dependence [unresolved] %{{.*}} on [[AS]]
+// CHECK-LABEL: } // end sil function 'testUnidentified'
+sil hidden [ossa] @testUnidentified : $@convention(method) (@owned B) -> () {
+bb0(%0 : @owned $B):
+  %1 = alloc_stack $B, let, name "self", argno 1
+  %2 = mark_unresolved_non_copyable_value [consumable_and_assignable] %1
+  store %0 to [init] %2
+  %4 = drop_deinit %2
+  debug_value %4, let, name "self", argno 1, expr op_deref
+  %6 = struct_element_addr %4, #B.ne
+  %7 = load_borrow %6
+
+  %8 = function_ref @getNEPointerToA : $@convention(thin) (@guaranteed NE) -> UnsafePointer<A>
+  %9 = apply %8(%7) : $@convention(thin) (@guaranteed NE) -> UnsafePointer<A>
+  %10 = struct_extract %9, #UnsafePointer._rawValue
+  %11 = pointer_to_address %10 to [strict] $*A
+  %12 = mark_dependence [unresolved] %11 on %7
+  %13 = begin_access [read] [unsafe] %12
+  %14 = load [trivial] %13
+  end_access %13
+
+  %16 = function_ref @useA : $@convention(thin) (A) -> ()
+  %17 = apply %16(%14) : $@convention(thin) (A) -> ()
+  end_borrow %7
+  %19 = struct_element_addr %4, #B.ne
+  %20 = begin_access [deinit] [static] %19
+  destroy_addr %20
+  end_access %20
+  dealloc_stack %1
+  %24 = tuple ()
+  return %24
+}
+
+// rdar://151231236 ([~Escapable] Missing 'overlapping acceses' error when called from client code, but exact same code
+// produces error in same module)
+//
+// Test access scope expansion over a switch_enum_addr
+// CHECK-LABEL: sil hidden [ossa] @testSwitchEnumAddr : $@convention(thin) @async (@inout AThing) -> @error any Error {
+// CHECK: bb0(%0 : $*AThing):
+// CHECK:   [[ATHING:%[0-9]+]] = mark_unresolved_non_copyable_value [consumable_and_assignable] %0
+// CHECK:   [[ACCESS:%[0-9]+]] = begin_access [modify] [unknown] [[ATHING]]
+// CHECK:   apply {{.*}}(%{{.*}}, [[ACCESS]]) : $@convention(thin) (@inout AThing) -> @lifetime(borrow address_for_deps 0) @out Container
+// CHECK:   mark_dependence_addr [unresolved] %{{.*}} on [[ACCESS]]
+// CHECK:   [[VIEW:%[0-9]+]] = project_box
+// CHECK:   [[TMP:%[0-9]+]] = alloc_stack $Optional<MutableView>
+// CHECK:   [[TMP_NC:%[0-9]+]] = mark_unresolved_non_copyable_value [consumable_and_assignable] [[TMP]]
+// CHECK:   apply %{{.*}} : $@convention(thin) (@in_guaranteed Container) -> @lifetime(copy 0) @out Optional<MutableView>
+// CHECK:   switch_enum_addr [[TMP_NC]], case #Optional.some!enumelt: bb2, case #Optional.none!enumelt: bb1
+// CHECK: bb1:
+// CHECK: bb2:
+// CHECK:   [[DATA:%[0-9]+]] = unchecked_take_enum_data_addr [[TMP_NC]], #Optional.some!enumelt
+// CHECK:   copy_addr [take] [[DATA]] to [init] [[VIEW]]
+// CHECK:   begin_access [modify] [unknown] [[ATHING]]
+// CHECK:   apply %{{.*}} : $@convention(thin) (@inout AThing) -> ()
+// CHECK:   [[ACCESS_VIEW:%[0-9]+]] = begin_access [modify] [unknown] [[VIEW]]
+// CHECK:   apply {{.*}} : $@convention(thin) (@inout MutableView) -> @lifetime(borrow address_for_deps 0) @owned MutableRawSpan
+// CHECK:   mark_dependence [unresolved]
+// CHECK:   end_access [[ACCESS_VIEW]]
+// CHECK:   end_access [[ACCESS]]
+// CHECK:   store
+// CHECK-LABEL: } // end sil function 'testSwitchEnumAddr'
+sil hidden [ossa] @testSwitchEnumAddr : $@convention(thin) @async (@inout AThing) -> @error any Error {
+bb0(%0 : $*AThing):
+  %1 = mark_unresolved_non_copyable_value [consumable_and_assignable] %0
+  %2 = alloc_box ${ var Container }, var, name "container"
+  %3 = begin_borrow [lexical] [var_decl] %2
+  %4 = project_box %3, 0
+  %5 = begin_access [modify] [unknown] %1
+
+  %6 = function_ref @getContainer : $@convention(thin) (@inout AThing) -> @lifetime(borrow address_for_deps 0) @out Container
+  %7 = apply %6(%4, %5) : $@convention(thin) (@inout AThing) -> @lifetime(borrow address_for_deps 0) @out Container
+  mark_dependence_addr [unresolved] %4 on %5
+  end_access %5
+  %10 = alloc_box ${ var MutableView }, var, name "view"
+  %11 = begin_borrow [lexical] [var_decl] %10
+  %12 = project_box %11, 0
+
+  %13 = alloc_stack $Optional<MutableView>
+  %14 = mark_unresolved_non_copyable_value [consumable_and_assignable] %13
+  %15 = begin_access [read] [unknown] %4
+  %16 = mark_unresolved_non_copyable_value [no_consume_or_assign] %15
+
+  %17 = function_ref @getMutableView : $@convention(thin) (@in_guaranteed Container) -> @lifetime(copy 0) @out Optional<MutableView>
+  %18 = apply %17(%14, %16) : $@convention(thin) (@in_guaranteed Container) -> @lifetime(copy 0) @out Optional<MutableView>
+  end_access %15
+
+  switch_enum_addr %14, case #Optional.some!enumelt: bb2, case #Optional.none!enumelt: bb1
+
+bb1:
+  end_borrow %11
+  dealloc_box [dead_end] %10
+  end_borrow %3
+  dealloc_box [dead_end] %2
+  unreachable
+
+bb2:
+  %44 = unchecked_take_enum_data_addr %14, #Optional.some!enumelt
+  copy_addr [take] %44 to [init] %12
+  dealloc_stack %13
+
+  %22 = begin_access [modify] [unknown] %1
+  %23 = function_ref @modAThing : $@convention(thin) (@inout AThing) -> ()
+  %24 = apply %23(%22) : $@convention(thin) (@inout AThing) -> ()
+  end_access %22
+  %26 = alloc_box ${ var MutableRawSpan }, var, name "span"
+  %27 = begin_borrow [lexical] [var_decl] %26
+  %28 = project_box %27, 0
+  %29 = begin_access [modify] [unknown] %12
+  %30 = mark_unresolved_non_copyable_value [assignable_but_not_consumable] %29
+
+  %31 = function_ref @getSpan : $@convention(thin) (@inout MutableView) -> @lifetime(borrow address_for_deps 0) @owned MutableRawSpan
+  %32 = apply %31(%30) : $@convention(thin) (@inout MutableView) -> @lifetime(borrow address_for_deps 0) @owned MutableRawSpan
+  %33 = mark_dependence [unresolved] %32 on %30
+  end_access %29
+  store %33 to [init] %28
+  end_borrow %27
+  destroy_value %26
+  end_borrow %11
+  destroy_value %10
+  end_borrow %3
+  destroy_value %2
+  %42 = tuple ()
+  return %42
+}
+
+// rdar://154406790 (Lifetime-dependent variable 'X' escapes its scope but only if actor/class is final)
+//
+// The end_access must be extended into the unreachable block past the end_borrow.
+//
+// CHECK-LABEL: sil hidden [ossa] @testInoutAtModify : $@convention(thin) (@inout S) -> () {
+// CHECK: bb0(%0 : $*S):
+// CHECK:   [[ACCESS:%[0-9]+]] = begin_access [modify] [unknown] %0
+// CHECK:   apply %{{.*}}([[ACCESS]]) : $@convention(thin) (@inout S) -> @lifetime(borrow 0) @owned MutNE
+// CHECK:   mark_dependence [unresolved] %{{.*}} on [[ACCESS]]
+// CHECK:   [[LB:%[0-9]+]] = load_borrow
+//
+// CHECK: bb1:
+// CHECK:   end_borrow [[LB]]
+// CHECK:   end_access [[ACCESS]]
+// CHECK:   return %16
+//
+// CHECK: bb2:
+// CHECK:   end_borrow [[LB]]
+// CHECK:   end_access [[ACCESS]]
+// CHECK:   unreachable
+// CHECK-LABEL: } // end sil function 'testInoutAtModify'
+sil hidden [ossa] @testInoutAtModify : $@convention(thin) (@inout S) -> () {
+bb0(%0 : $*S):
+  %1 = alloc_box ${ let MutNE }, let, name "ne"
+  %2 = begin_borrow [lexical] [var_decl] %1
+  %3 = project_box %2, 0
+  %4 = begin_access [modify] [unknown] %0
+
+  %6 = function_ref @getMutNE : $@convention(thin) (@inout S) -> @lifetime(borrow 0) @owned MutNE
+  %7 = apply %6(%4) : $@convention(thin) (@inout S) -> @lifetime(borrow 0) @owned MutNE
+  %8 = mark_dependence [unresolved] %7 on %4
+  store %8 to [init] %3
+  end_access %4
+  %11 = mark_unresolved_non_copyable_value [no_consume_or_assign] %3
+  %12 = load_borrow %11
+  cond_br undef, bb1, bb2
+
+bb1:
+  end_borrow %12
+  end_borrow %2
+  destroy_value %1
+  %15 = tuple ()
+  return %15
+
+bb2:
+  end_borrow %12
+  end_borrow %2
+  dealloc_box [dead_end] %1
+  unreachable
+}
+
+// Test trivial alloc_stack extension when used by an addressable dependency.
+//
+// CHECK-LABEL: sil hidden [noinline] [ossa] @testTempTrivialStackCopy : $@convention(thin) () -> () {
+// CHECK:   [[STK:%[0-9]+]] = alloc_stack $InlineInt
+// CHECK:   [[MD:%[0-9]+]] = mark_dependence [unresolved] %{{.*}} on [[STK]]
+// CHECK:   [[VAR:%[0-9]+]] = move_value [var_decl] [[MD]]
+// CHECK: bb3:                                              // Preds: bb2 bb1
+// CHECK:   [[BORROW:%[0-9]+]] = begin_borrow [[VAR]]
+// CHECK:   apply %{{.*}}([[BORROW]]) : $@convention(thin) (@guaranteed Span<Int>) -> ()
+// CHECK:   destroy_value [[VAR]]
+// CHECK:   dealloc_stack [[STK]]
+// CHECK-LABEL: } // end sil function 'testTempTrivialStackCopy'
+sil hidden [noinline] [ossa] @testTempTrivialStackCopy : $@convention(thin) () -> () {
+bb0:
+  %0 = function_ref @globalAddress : $@convention(thin) () -> Builtin.RawPointer
+  %1 = apply %0() : $@convention(thin) () -> Builtin.RawPointer
+  %2 = pointer_to_address %1 to [strict] $*InlineInt
+  %3 = begin_access [read] [dynamic] %2
+  %4 = load [trivial] %3
+  end_access %3
+  %6 = alloc_stack $InlineInt
+  store %4 to [trivial] %6
+
+  %8 = function_ref @addressInt : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address_for_deps 0) @owned Span<Int>
+  %9 = apply %8(%6) : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address_for_deps 0) @owned Span<Int>
+  %10 = mark_dependence [unresolved] %9 on %6
+  %11 = move_value [var_decl] %10
+  cond_br undef, bb1, bb2
+
+bb1:
+  dealloc_stack %6
+  br bb3
+bb2:
+  dealloc_stack %6
+  br bb3
+
+bb3:
+  %13 = begin_borrow %11
+
+  %14 = function_ref @useSpan : $@convention(thin) (@guaranteed Span<Int>) -> ()
+  %15 = apply %14(%13) : $@convention(thin) (@guaranteed Span<Int>) -> ()
+  end_borrow %13
+  destroy_value %11
+  %18 = tuple ()
+  return %18
+}
diff --git a/test/SILOptimizer/lifetime_dependence/semantics.swift b/test/SILOptimizer/lifetime_dependence/semantics.swift
index 4dfcec2565417..e81b716846888 100644
--- a/test/SILOptimizer/lifetime_dependence/semantics.swift
+++ b/test/SILOptimizer/lifetime_dependence/semantics.swift
@@ -4,60 +4,17 @@
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
 // RUN:   -enable-builtin-module \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-feature AddressableParameters \
 // RUN:   -enable-experimental-feature AddressableTypes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_AddressableParameters
 // REQUIRES: swift_feature_AddressableTypes
 
 import Builtin
 
-@_unsafeNonescapableResult
-@_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, borrowing source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
-
-/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
-/// a value identical to `dependent` that inherits all lifetime dependencies from
-/// the `source` argument.
-@_unsafeNonescapableResult
-@_transparent
-@lifetime(copy source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, copying source: borrowing U
-) -> T {
-  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
-  // should be expressed by a builtin that is hidden within the function body.
-  dependent
-}
-
-/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
-/// a value identical to `dependent` that inherits all lifetime dependencies from
-/// the `source` argument.
-@_unsafeNonescapableResult
-@_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, mutating source: inout U
-) -> T {
-  dependent
-}
-
 struct NotEscapable: ~Escapable {}
 
 // Lifetime dependence semantics by example.
@@ -65,13 +22,13 @@ public struct Span<T>: ~Escapable {
   private var base: UnsafePointer<T>?
   private var count: Int
 
-  @lifetime(borrow base)
+  @_lifetime(borrow base)
   init(base: UnsafePointer<T>?, count: Int) {
     self.base = base
     self.count = count
   }
 
-  @lifetime(borrow generic)
+  @_lifetime(borrow generic)
   init<S>(base: UnsafePointer<T>?, count: Int, generic: borrowing S) {
     self.base = base
     self.count = count
@@ -85,7 +42,7 @@ public struct Span<T>: ~Escapable {
 }
 
 extension Span {
-  @lifetime(copy self)
+  @_lifetime(copy self)
   consuming func dropFirst() -> Span<T> {
     let nextPointer = self.base.flatMap { $0 + 1 }
     let local = Span(base: nextPointer, count: self.count - 1)
@@ -94,7 +51,7 @@ extension Span {
 }
 
 extension Span {
-  @lifetime(copy self)
+  @_lifetime(copy self)
   mutating func droppingPrefix(length: Int) -> /* */ Span<T> {
     let oldBase = base
     let result = Span(base: oldBase, count: length)
@@ -110,7 +67,7 @@ struct MutableSpan<T>: ~Escapable, ~Copyable {
   let base: UnsafeMutablePointer<T>
   let count: Int
 
-  @lifetime(borrow base)
+  @_lifetime(borrow base)
   init(base: UnsafeMutablePointer<T>, count: Int) {
     self.base = base
     self.count = count
@@ -118,7 +75,7 @@ struct MutableSpan<T>: ~Escapable, ~Copyable {
 }
 
 extension Array {
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func span() -> Span<Element> {
     /* not the real implementation */
     let p = self.withUnsafeBufferPointer { $0.baseAddress! }
@@ -128,7 +85,7 @@ extension Array {
 }
 
 extension Array {
-  @lifetime(borrow self)
+  @_lifetime(&self)
   mutating func mutableSpan() -> MutableSpan<Element> {
     /* not the real implementation */
     let p = self.withUnsafeMutableBufferPointer { $0.baseAddress! }
@@ -140,7 +97,7 @@ extension Array {
 struct InnerTrivial {
   var p: UnsafePointer<Int>
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func span() -> Span<Int> {
     Span(base: p, count: 1)
   }
@@ -149,13 +106,21 @@ struct InnerTrivial {
 struct TrivialHolder {
   var p: UnsafePointer<Int>
   var pa: UnsafePointer<AddressableInt>
+  var mp: UnsafeMutablePointer<Int>
 
   var addressableInt: AddressableInt { unsafeAddress { pa } }
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func span() -> Span<Int> {
     Span(base: p, count: 1)
   }
+
+  @_lifetime(&self)
+  mutating func mutableSpan() -> MutableSpan<Int> {
+    MutableSpan(base: mp, count: 1)
+  }
+
+  mutating func modify() {}
 }
 
 struct Holder {
@@ -165,7 +130,7 @@ struct Holder {
 
   var addressableInt: AddressableInt { unsafeAddress { pa } }
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func span() -> Span<Int> {
     Span(base: p, count: 1)
   }
@@ -175,7 +140,7 @@ struct Holder {
 struct AddressableInt {
   let value: Int
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func span() -> Span<Int> {
     // TODO: we actually want the address of self.value
     let p = UnsafePointer<Int>(Builtin.unprotectedAddressOfBorrow(self))
@@ -188,7 +153,7 @@ struct AddressableInt {
 struct AddressableObject {
   let object: AnyObject
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   borrowing func span() -> Span<AnyObject> {
     // TODO: we actually want the address of self.object
     let p = UnsafePointer<AnyObject>(Builtin.unprotectedAddressOfBorrow(self))
@@ -223,24 +188,38 @@ struct Outer {
     get { _innerObject }
   }
 
-  /* TODO: rdar://137608270 Add Builtin.addressof() support for @addressable arguments
-  @addressableSelf
-  var innerAddress: Inner {
+  var innerAddress: InnerTrivial {
+    @_addressableSelf
     unsafeAddress {
-      Builtin.addressof(inner)
+      UnsafePointer<InnerTrivial>(Builtin.addressOfBorrow(_innerTrivial))
     }
   }
-  */
 }
 
 func parse(_ span: Span<Int>) {}
 
-@lifetime(copy arg)
+@_lifetime(copy arg)
 func copySpan<T>(_ arg: Span<T>) -> /* */ Span<T> { arg }
 
-@lifetime(borrow arg)
+@_lifetime(borrow arg)
 func reborrowSpan<T>(_ arg: Span<T>) -> Span<T> { arg }
 
+@_lifetime(&arg)
+func reborrowGenericInout<T: ~Escapable>(_ arg: inout T) -> T { arg }
+
+@_lifetime(copy arg)
+func inheritSpan<T>(_ arg: Span<T>) -> Span<T> { arg }
+
+@_lifetime(copy arg)
+func inheritGeneric<T: ~Escapable>(_ arg: consuming T) -> T { arg }
+
+public struct NE: ~Escapable {}
+
+@_lifetime(&ne)
+func borrowNE<T: ~Escapable>(ne: inout T) -> T {
+  ne
+}
+
 // =============================================================================
 // Initialization
 // =============================================================================
@@ -248,7 +227,7 @@ func reborrowSpan<T>(_ arg: Span<T>) -> Span<T> { arg }
 struct View: ~Escapable {
   let owner: AnyObject
 
-  @lifetime(borrow owner)
+  @_lifetime(borrow owner)
   init(owner: borrowing AnyObject) {
     self.owner = copy owner // OK
   }
@@ -258,12 +237,12 @@ struct MutableView: ~Escapable, ~Copyable {
   let owner: AnyObject
 
   // A copy of a borrow is indistinguishable with the borrow scope.
-  @lifetime(borrow owner)
+  @_lifetime(borrow owner)
   init(owner: borrowing AnyObject) {
     self.owner = copy owner // OK
   }
 
-  @lifetime(borrow mutableOwner)
+  @_lifetime(&mutableOwner)
   init(mutableOwner: inout AnyObject) {
     // Initialization of a ~Escapable value is unenforced. So we can initialize
     // the `owner` property without locally borrowing `mutableOwner`.
@@ -278,7 +257,7 @@ struct Container<T> {
 }
 
 // Dependence on an empty initialized value should be scoped to variable decl.
-@lifetime(copy x)
+@_lifetime(copy x)
 func f(x: NotEscapable) -> NotEscapable {
   let local = NotEscapable() // expected-error {{lifetime-dependent variable 'local' escapes its scope}}
   // expected-note @-1{{it depends on the lifetime of this parent value}}
@@ -340,6 +319,30 @@ func testInheritedCopyVar(_ arg: [Int] ) {
   parse(result) // ✅ Safe: within lifetime of 'a'
 }
 
+@_lifetime(copy span)
+public func testBorrowInheritedArg<T>(_ span: Span<T>) -> Span<T> {
+  reborrowSpan(span) // expected-error {{lifetime-dependent value escapes its scope}}
+  // expected-note @-2{{it depends on the lifetime of argument 'span'}}
+} // expected-note {{this use causes the lifetime-dependent value to escape}}
+
+@_lifetime(copy t)
+public func testBorrowInheritedInoutArg<T: ~Escapable>(_ t: inout T) -> T {
+  // expected-error @-1{{lifetime-dependent variable 't' escapes its scope}}
+  // expected-note @-2{{it depends on the lifetime of argument 't'}}
+  reborrowGenericInout(&t)
+  // expected-note @-1{{this use causes the lifetime-dependent value to escape}}
+}
+
+@_lifetime(copy span)
+public func testCopyInheritedArg<T>(_ span: Span<T>) -> Span<T> {
+  inheritSpan(span)
+}
+
+@_lifetime(copy t)
+public func testCopyInheritedGenericArg<T: ~Escapable>(_ t: consuming T) -> T {
+  inheritGeneric(t)
+}
+
 // =============================================================================
 // Scoped dependence on inherited dependence
 // =============================================================================
@@ -364,11 +367,28 @@ func testScopedOfInheritedWithLet(_ arg: [Int] ) {
   _ = result
 } // expected-note {{this use of the lifetime-dependent value is out of scope}}
 
+// Test a scoped dependence on an inherited inout argument.
+//
+// If testScopedOfInheritedWithLet is not an error, then its result can outlive its borrowed value:
+//  let ne1 = NE()
+//  var ne2 = ne1
+//  let dep = foo(ne: &ne2)
+//  _ = consume ne2
+//  _ = dep
+//
+@_lifetime(copy ne)
+public func testScopedOfInheritedInout<T: ~Escapable>(ne: inout T) -> T {
+  // expected-error @-1{{lifetime-dependent variable 'ne' escapes its scope}}
+  // expected-note  @-2{{it depends on the lifetime of argument 'ne'}}
+  borrowNE(ne: &ne)
+  // expected-note  @-1{{this use causes the lifetime-dependent value to escape}}
+}
+
 // =============================================================================
 // Scoped dependence on trivial values
 // =============================================================================
 
-@lifetime(borrow a)
+@_lifetime(borrow a)
 func testTrivialScope<T>(a: Array<T>) -> Span<T> {
   let p = a.withUnsafeBufferPointer { $0.baseAddress! }
   return Span(base: p, count: 1)
@@ -392,7 +412,7 @@ public func testTrivialLocalDeadEnd(p: UnsafePointer<Int>) {
 
 // Test dependence on a borrow of a trivial inout. The access scope can be ignored since we don't care about the
 // in-memory value.
-@lifetime(borrow p)
+@_lifetime(&p)
 public func testTrivialInoutBorrow(p: inout UnsafePointer<Int>) -> Span<Int> {
   return Span(base: p, count: 1)
 }
@@ -403,27 +423,27 @@ public func testTrivialInoutBorrow(p: inout UnsafePointer<Int>) -> Span<Int> {
 
 private let immortalInt = 0
 
-private let immortalString = ""
+private let immortalStrings: [String] = []
 
-@lifetime(immortal)
+@_lifetime(immortal)
 func testImmortalInt() -> Span<Int> {
   let nilBasedBuffer = UnsafeBufferPointer<Int>(start: nil, count: 0)
   let span = Span(base: nilBasedBuffer.baseAddress, count: nilBasedBuffer.count)
   return _overrideLifetime(span, borrowing: immortalInt)
 }
 
-@lifetime(immortal)
-func testImmortalString() -> Span<String> {
-  let nilBasedBuffer = UnsafeBufferPointer<String>(start: nil, count: 0)
+@_lifetime(immortal)
+func testImmortalStrings() -> Span<[String]> {
+  let nilBasedBuffer = UnsafeBufferPointer<[String]>(start: nil, count: 0)
   let span = Span(base: nilBasedBuffer.baseAddress, count: nilBasedBuffer.count)
-  return _overrideLifetime(span, borrowing: immortalString)
+  return _overrideLifetime(span, borrowing: immortalStrings)
 }
 
 let ptr = UnsafePointer<Int>(bitPattern: 1)!
 let globalTrivial = InnerTrivial(p: ptr)
 
 // An immortal span can depend on a caller's local borrow scope even though the callee sees no such dependency.
-@lifetime(borrow local)
+@_lifetime(borrow local)
 func testGlobal(local: InnerTrivial) -> Span<Int> {
   globalTrivial.span()
 }
@@ -432,44 +452,63 @@ func testGlobal(local: InnerTrivial) -> Span<Int> {
 // Scoped dependence on mutable values
 // =============================================================================
 
-@lifetime(borrow a)
+@_lifetime(&a)
 func testInoutBorrow(a: inout [Int]) -> Span<Int> {
-  a.span() // expected-error {{lifetime-dependent value escapes its scope}}
-  // expected-note @-1{{it depends on this scoped access to variable 'a'}}
-} // expected-note {{this use causes the lifetime-dependent value to escape}}
+  a.span() // OK
+}
 
-@lifetime(borrow a)
+@_lifetime(&a)
 func testInoutMutableBorrow(a: inout [Int]) -> MutableSpan<Int> {
   a.mutableSpan()
 }
 
+@_lifetime(&h)
+func testTrivialWriteConflict(h: inout TrivialHolder) -> MutableSpan<Int> {
+  let span = h.mutableSpan() // expected-error{{overlapping accesses to 'h', but modification requires exclusive access; consider copying to a local variable}}
+  h.modify() // expected-note{{conflicting access is here}}
+  return span
+}
+
+func makeMutableSpan(_ p: inout UnsafeMutablePointer<UInt8>) -> MutableSpan<UInt8> {
+  MutableSpan(base: p, count: 1)
+}
+
+struct TestInoutUnsafePointerExclusivity {
+  var pointer: UnsafeMutablePointer<UInt8>
+
+  @_lifetime(&self)
+  mutating func testInoutUnsafePointerExclusivity() -> MutableSpan<UInt8> {
+    let span1 = makeMutableSpan(&self.pointer) // expected-error{{overlapping accesses to 'self.pointer', but modification requires exclusive access; consider copying to a local variable}}
+    _ = makeMutableSpan(&self.pointer) // expected-note{{conflicting access is here}}
+    return span1
+  }
+}
+
 // =============================================================================
 // Scoped dependence on property access
 // =============================================================================
 
 extension Container {
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   func span() -> Span<T> {
     // borrowing the 'pointer' member is allowed.
     Span(base: self.pointer, count: self.count) // OK
   }
 
-  @lifetime(borrow self)
+  @_lifetime(borrow self)
   func view() -> View {
     // borrowing the 'view' member is allowed.
     View(owner: self.owner) // OK
   }
 
-  @lifetime(borrow self)
+  @_lifetime(&self)
   mutating func mutableView() -> MutableView {
-    // Reading 'self.owner' creates a local borrow scope. This new MutableView
-    // depends on a the local borrow scope for 'self.owner', so it cannot be
-    // returned.
-    MutableView(owner: self.owner) // expected-error {{lifetime-dependent value escapes its scope}}
-    // expected-note @-1{{it depends on this scoped access to variable 'self'}}
-  } // expected-note    {{this use causes the lifetime-dependent value to escape}}
-
-  @lifetime(borrow self)
+    // Reading 'self.owner' creates a local borrow scope. The caller's exclusive access on 'self' is sufficient for the
+    // result.
+    MutableView(owner: self.owner) // OK
+  }
+
+  @_lifetime(&self)
   mutating func mutableViewModifiesOwner() -> MutableView {
     // Passing '&self.owner' inout creates a nested exclusive access that must extend to all uses of the new
     // MutableView. This is allowed because the nested access is logically extended to the end of the function (without
@@ -477,7 +516,7 @@ extension Container {
     MutableView(mutableOwner: &self.owner)
   }
 
-  @lifetime(borrow self)
+  @_lifetime(&self)
   mutating func mutableSpan() -> MutableSpan<T> {
     // Reading 'self.pointer' creates a local borrow scope. The local borrow
     // scope is ignored because 'pointer' is a trivial value. Instead, the new
@@ -486,22 +525,22 @@ extension Container {
   }
 }
 
-@lifetime(borrow outer)
+@_lifetime(borrow outer)
 func testBorrowStoredTrivial(outer: Outer) -> Span<Int> {
   outer._innerTrivial.span()
 }
 
-@lifetime(borrow outer)
+@_lifetime(borrow outer)
 func testBorrowStoredObject(outer: Outer) -> Span<Int> {
   outer._innerObject.span()
 }
 
-@lifetime(borrow outer)
+@_lifetime(borrow outer)
 func testBorrowTrivialAddressProjection(outer: Outer) -> Span<Int> {
   outer.innerTrivialAddress.span()
 }
 
-@lifetime(borrow outer)
+@_lifetime(borrow outer)
 func testBorrowObjectAddressProjection(outer: Outer) -> Span<Int> {
   outer.innerObjectAddress.span()
 }
@@ -512,9 +551,6 @@ func testExprExtendTrivialTemp(outer: Outer) {
 
 func testExprExtendObjectTemp(outer: Outer) {
   parse(outer.innerObjectTemp.span())
-  // expected-error @-1{{lifetime-dependent value escapes its scope}}
-  // expected-note  @-2{{it depends on the lifetime of this parent value}}
-  // expected-note  @-3{{this use of the lifetime-dependent value is out of scope}}
 }
 
 func testLocalExtendTrivialTemp(outer: Outer) {
@@ -524,19 +560,17 @@ func testLocalExtendTrivialTemp(outer: Outer) {
 
 func testLocalExtendObjectTemp(outer: Outer) {
   let span = outer.innerObjectTemp.span()
-  // expected-error @-1{{lifetime-dependent variable 'span' escapes its scope}}
-  // expected-note  @-2{{it depends on the lifetime of this parent value}}
-  parse(span) // expected-note {{this use of the lifetime-dependent value is out of scope}}
+  parse(span)
 }
 
-@lifetime(borrow outer)
+@_lifetime(borrow outer)
 func testReturnTrivialTemp(outer: Outer) -> Span<Int> {
   outer.innerTrivialTemp.span()
   // expected-error @-1{{lifetime-dependent value escapes its scope}}
   // expected-note  @-2{{it depends on the lifetime of this parent value}}
 } // expected-note {{this use causes the lifetime-dependent value to escape}}
 
-@lifetime(borrow outer)
+@_lifetime(borrow outer)
 func testReturnObjectTemp(outer: Outer) -> Span<Int> {
   outer.innerObjectTemp.span()
   // expected-error @-1{{lifetime-dependent value escapes its scope}}
@@ -548,56 +582,51 @@ func testReturnObjectTemp(outer: Outer) -> Span<Int> {
 // =============================================================================
 
 // @_addressableForDependencies supports returning a Span.
-@lifetime(borrow arg)
+@_lifetime(borrow arg)
 func testAddressableInt(arg: AddressableInt) -> Span<Int> {
   arg.span()
 }
 
 // @_addressableForDependencies supports returning a Span.
-@lifetime(borrow arg)
+@_lifetime(borrow arg)
 func testAddressableObject(arg: AddressableObject) -> Span<AnyObject> {
   arg.span()
 }
 
 // Helper: create a dependence on the argument's address.
-@lifetime(borrow arg)
+@_lifetime(borrow arg)
 func dependsOnTrivialAddressHelper(arg: @_addressable TrivialHolder) -> Span<Int> {
   arg.span()
 }
 
 // Helper: create a dependence on the argument's address.
-@lifetime(borrow arg)
+@_lifetime(borrow arg)
 func dependsOnAddressHelper(arg: @_addressable Holder) -> Span<Int> {
   arg.span()
 }
 
-/* TODO: requires -enable-address-dependencies
-
 // Non-addressable error returning a Span.
-@lifetime(borrow arg)
+@_lifetime(borrow arg)
 func testTrivialNonAddressable(arg: TrivialHolder) -> Span<Int> {
   dependsOnTrivialAddressHelper(arg: arg)
-  // todo-error @-1{{lifetime-dependent value escapes its scope}
-  // todo-note  @-3{{it depends on the lifetime of variable 'arg'}}
-} // todo-note  {{this use causes the lifetime-dependent value to escape}}
+  // expected-error @-1{{lifetime-dependent value escapes its scope}}
+  // expected-note  @-3{{it depends on the lifetime of argument 'arg'}}
+} // expected-note  {{this use causes the lifetime-dependent value to escape}}
 
 // Non-addressable error returning a Span.
-@lifetime(borrow arg)
+@_lifetime(borrow arg)
 func testNonAddressable(arg: Holder) -> Span<Int> {
   dependsOnAddressHelper(arg: arg)
-  // todo-error @-1{{lifetime-dependent value escapes its scope}
-  // todo-note  @-3{{it depends on the lifetime of variable 'arg'}}
-} // todo-note  {{this use causes the lifetime-dependent value to escape}}
-*/
+  // expected-error @-1{{lifetime-dependent value escapes its scope}}
+  // expected-note  @-3{{it depends on the lifetime of argument 'arg'}}
+} // expected-note  {{this use causes the lifetime-dependent value to escape}}
 
-/* TODO: rdar://145872854 (SILGen: @addressable inout arguments are copied)
-@lifetime(borrow arg)
+@_lifetime(&arg)
 func test(arg: inout AddressableInt) -> Span<Int> {
   arg.span()
 }
 
 // unsafeAddress generates an addressable value with a local scope.
-@lifetime(borrow arg)
 func testBorrowedAddressableInt(arg: Holder) -> Int {
   let span = arg.addressableInt.span()
   return span[0]
@@ -605,11 +634,9 @@ func testBorrowedAddressableInt(arg: Holder) -> Int {
 
 // unsafeAddress generates an addressable value.
 // Error returning a dependence on its local scope.
-@lifetime(borrow arg)
+@_lifetime(borrow arg)
 func testBorrowedAddressableIntReturn(arg: Holder) -> Span<Int> {
   arg.addressableInt.span()
-  // todo-error @-1{{lifetime-dependent value escapes its scope}
-  // todo-note  @-2{{it depends on the lifetime of this parent value}}
-} // todo-note  {{this use causes the lifetime-dependent value to escape}}
-
-*/
+  // expected-error @-1{{lifetime-dependent value escapes its scope}}
+  // expected-note  @-2{{it depends on the lifetime of this parent value}}
+} // expected-note  {{this use causes the lifetime-dependent value to escape}}
diff --git a/test/SILOptimizer/lifetime_dependence/specialize.sil b/test/SILOptimizer/lifetime_dependence/specialize.sil
new file mode 100644
index 0000000000000..16374f39d06f8
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/specialize.sil
@@ -0,0 +1,56 @@
+// RUN: %target-sil-opt \
+// RUN:   -generic-specializer \
+// RUN:   -sil-verify-all \
+// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature AddressableParameters \
+// RUN:   -enable-experimental-feature AddressableTypes \
+// RUN:   %s | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_AddressableParameters
+// REQUIRES: swift_feature_AddressableTypes
+
+// REQUIRES: PTRSIZE=64
+
+// Test the SIL representation for lifetime dependence scope fixup.
+
+sil_stage raw
+
+import Builtin
+import Swift
+
+sil @makeSpan : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafePointer<τ_0_0>, Int, @thin Span<τ_0_0>.Type) -> @lifetime(borrow 0) @owned Span<τ_0_0>
+
+// Ensure that the addressable argument is not deleted.
+//
+// CHECK-LABEL: sil shared [ossa] @$s12getSpanOfOneSi_Tg5 : $@convention(thin) (@in_guaranteed CollectionOfOne<Int>) -> @lifetime(borrow address_for_deps 0) @owned Span<Int> {
+sil shared [ossa] @getSpanOfOne : $@convention(thin) <Element> (@in_guaranteed CollectionOfOne<Element>) -> @lifetime(borrow address_for_deps 0) @owned Span<Element> {
+[global: ]
+bb0(%0 : $*CollectionOfOne<Element>):
+  %1 = address_to_pointer [stack_protection] %0 : $*CollectionOfOne<Element> to $Builtin.RawPointer
+  %2 = struct $UnsafePointer<Element> (%1 : $Builtin.RawPointer)
+  %3 = metatype $@thin Span<Element>.Type
+  %4 = integer_literal $Builtin.Int64, 1
+  %5 = struct $Int (%4 : $Builtin.Int64)
+  %6 = function_ref @makeSpan : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafePointer<τ_0_0>, Int, @thin Span<τ_0_0>.Type) -> @lifetime(borrow 0) @owned Span<τ_0_0>
+  %7 = apply %6<Element>(%2, %5, %3) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (UnsafePointer<τ_0_0>, Int, @thin Span<τ_0_0>.Type) -> @lifetime(borrow 0) @owned Span<τ_0_0>
+  return %7 : $Span<Element>
+}
+
+sil hidden [ossa] @testGetSpanOfOne : $@convention(thin) (@in_guaranteed CollectionOfOne<Int>) -> () {
+bb0(%0 : $*CollectionOfOne<Int>):
+  %temp = alloc_stack $CollectionOfOne<Int>
+  %load = load [trivial] %0 : $*CollectionOfOne<Int>
+  %borrow = store_borrow %load to %temp : $*CollectionOfOne<Int>
+
+  %fget = function_ref @getSpanOfOne : $@convention(thin) <Element> (@in_guaranteed CollectionOfOne<Element>) -> @lifetime(borrow address_for_deps 0) @owned Span<Element>
+  %span = apply %fget<Int>(%borrow) : $@convention(thin) <τ_0_0> (@in_guaranteed CollectionOfOne<τ_0_0>) -> @lifetime(borrow address_for_deps 0) @owned Span<τ_0_0>
+
+  destroy_value %span : $Span<Int>
+  end_borrow %borrow : $*CollectionOfOne<Int>
+  dealloc_stack %temp : $*CollectionOfOne<Int>
+
+  %99 = tuple ()
+  return %99 : $()
+}
diff --git a/test/SILOptimizer/lifetime_dependence/stdlib_span.swift b/test/SILOptimizer/lifetime_dependence/stdlib_span.swift
index bbf61c5862e6f..04e88bae63ca8 100644
--- a/test/SILOptimizer/lifetime_dependence/stdlib_span.swift
+++ b/test/SILOptimizer/lifetime_dependence/stdlib_span.swift
@@ -4,10 +4,10 @@
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
 // RUN:   -disable-access-control \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // Test dependencies on the standard library Span APIs.
 
@@ -18,7 +18,7 @@
 extension UnsafeRawBufferPointer {
   @available(SwiftStdlib 6.2, *)
   public var storage: RawSpan {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     get {
       let span = RawSpan(_unsafeBytes: self)
       return _overrideLifetime(span, borrowing: self)
@@ -37,14 +37,14 @@ func testUBPStorage(ubp: UnsafeRawBufferPointer) {
 }
 
 @available(SwiftStdlib 6.2, *)
-@lifetime(borrow ubp)
+@_lifetime(borrow ubp)
 func testUBPStorageReturn(ubp: UnsafeRawBufferPointer) -> RawSpan {
   // 'storage' can be returned since the function's return value also has a dependence on 'ubp'.
   return ubp.storage
 }
 
 @available(SwiftStdlib 6.2, *)
-@lifetime(borrow ubp)
+@_lifetime(borrow ubp)
 func testUBPStorageCopy(ubp: UnsafeRawBufferPointer) -> RawSpan {
   let localBuffer = ubp
   return localBuffer.storage // expected-error {{lifetime-dependent value escapes its scope}}
diff --git a/test/SILOptimizer/lifetime_dependence/verify_diagnostics.sil b/test/SILOptimizer/lifetime_dependence/verify_diagnostics.sil
index 230944440a6cb..eeb8e0317f482 100644
--- a/test/SILOptimizer/lifetime_dependence/verify_diagnostics.sil
+++ b/test/SILOptimizer/lifetime_dependence/verify_diagnostics.sil
@@ -2,21 +2,21 @@
 // RUN:   --lifetime-dependence-diagnostics \
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
-// RUN:   -module-name Swift \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
+// RUN:   -enable-experimental-feature AddressableTypes \
 // RUN:   -o /dev/null
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_AddressableTypes
 
 // Verify diagnostics from the LifetimeDependenceDiagnostics pass.
 
 sil_stage raw
 
 import Builtin
-
-@_marker protocol Copyable: ~Escapable {}
-@_marker protocol Escapable: ~Copyable {}
+import Swift
+import SwiftShims
 
 class C {}
 
@@ -25,7 +25,7 @@ struct NE : ~Escapable {}
 struct NEObject : ~Escapable {
   var c: C
 
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init()
 }
 
@@ -33,9 +33,46 @@ public struct Holder {
   var c: C
 }
 
+public struct TrivialHolder {
+  var p: Builtin.RawPointer
+}
+
+struct A {}
+
+struct NCWrapper : ~Copyable, ~Escapable {
+  @_hasStorage let a: NE { get }
+  deinit
+}
+
+sil @getNEPointer : $@convention(thin) (@guaranteed NE) -> Builtin.RawPointer
+sil @useA : $@convention(thin) (A) -> ()
 sil @makeNE : $@convention(thin) () -> @lifetime(immortal) @owned NE
 sil @makeNEObject : $@convention(thin) () -> @lifetime(immortal) @owned NEObject
-sil @useNE : $@convention(thin) (NE) -> ()
+sil @useNE : $@convention(thin) (@guaranteed NE) -> ()
+sil @reborrowNE : $@convention(thin) (@guaranteed NE) -> @lifetime(borrow 0) @owned NE
+
+sil @initHolder : $@convention(thin) () -> @out Holder
+sil @getNE : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address_for_deps 0) @owned NE
+sil @getNEIndirect : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address_for_deps 0) @out NE
+
+sil @initTrivialHolder : $@convention(thin) () -> @out TrivialHolder
+sil @getTrivialNE : $@convention(thin) (@in_guaranteed TrivialHolder) -> @lifetime(borrow address_for_deps 0) @owned NE
+
+sil @makeHolder: $@convention(method) (@thin Holder.Type) -> @owned Holder // user: %6
+sil @getGeneric : $@convention(thin) <τ_0_0 where τ_0_0 : ~Escapable> (@guaranteed Holder, @thick τ_0_0.Type) -> @lifetime(borrow 0) @out τ_0_0 // user: %12
+
+@_addressableForDependencies
+public struct InlineInt {
+  var i: Int
+}
+sil @globalAddress : $@convention(thin) () -> Builtin.RawPointer
+sil @addressInt : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address_for_deps 0) @owned Span<Int>
+sil @addressOfInt : $@convention(thin) (@in_guaranteed Int) -> @lifetime(borrow address 0) @owned Span<Int>
+sil @noAddressInt : $@convention(thin) (@in_guaranteed Int) -> @lifetime(borrow 0) @owned Span<Int>
+sil @useSpan : $@convention(thin) (@guaranteed Span<Int>) -> ()
+sil @useRawSpan : $@convention(thin) (@guaranteed RawSpan) -> @error any Error
+
+sil @getInlineSpan : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address 0) @owned RawSpan
 
 // Test returning a owned dependence on a trivial value
 sil [ossa] @return_trivial_dependence : $@convention(thin) (@guaranteed C) -> @lifetime(borrow 0) @owned NE {
@@ -71,8 +108,8 @@ bb0(%0 : @owned $Holder):
   %c1 = apply %f1() : $@convention(thin) () -> @lifetime(immortal) @owned NE
   %md = mark_dependence [unresolved] %c1 on %sb
   %mv = move_value [var_decl] %md
-  %f2 = function_ref @useNE : $@convention(thin) (NE) -> ()
-  %c2 = apply %f2(%mv) : $@convention(thin) (NE) -> ()
+  %f2 = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %c2 = apply %f2(%mv) : $@convention(thin) (@guaranteed NE) -> ()
   destroy_value %mv
   end_borrow %sb
   dealloc_stack %stk
@@ -80,3 +117,306 @@ bb0(%0 : @owned $Holder):
   %99 = tuple ()
   return %99
 }
+
+// Test that local variable analysis can handle an address-type mark_dependence on an address base. The drop_deinit
+// also creates an an unknown address scope, preventing diagnostics from promoting the mark_dependence to noescape.
+sil [ossa] @testMarkDepAddressProjection : $@convention(thin) (@owned NCWrapper) -> () {
+bb0(%0 : @owned $NCWrapper):
+  %1 = alloc_stack $NCWrapper, let, name "self", argno 1
+  store %0 to [init] %1
+  %3 = drop_deinit %1
+  %4 = struct_element_addr %3, #NCWrapper.a
+  %5 = load_borrow %4
+
+  %6 = function_ref @getNEPointer : $@convention(thin) (@guaranteed NE) -> Builtin.RawPointer
+  %7 = apply %6(%5) : $@convention(thin) (@guaranteed NE) -> Builtin.RawPointer
+  %8 = pointer_to_address %7 to [strict] $*A
+  %9 = mark_dependence [unresolved] %8 on %4
+  %10 = begin_access [read] [unsafe] %9
+  %11 = load [trivial] %10
+  end_access %10
+
+  %13 = function_ref @useA : $@convention(thin) (A) -> ()
+  %14 = apply %13(%11) : $@convention(thin) (A) -> ()
+  end_borrow %5
+  dealloc_stack %1
+  %17 = tuple ()
+  return %17
+}
+
+// Test that LifetimeDependence.Scope recognizes a singly-initialized alloc_stack.
+sil [ossa] @testStackInit : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_stack [lexical] [var_decl] $Holder, let, name "v"
+  %1 = function_ref @initHolder : $@convention(thin) () -> @out Holder
+  %2 = apply %1(%0) : $@convention(thin) () -> @out Holder
+  %3 = function_ref @getNE : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address_for_deps 0) @owned NE
+  %4 = apply %3(%0) : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address_for_deps 0) @owned NE
+  %5 = mark_dependence [unresolved] %4 on %0
+  %6 = move_value [var_decl] %5
+  %7 = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %8 = apply %7(%6) : $@convention(thin) (@guaranteed NE) -> ()
+  destroy_value %6
+  destroy_addr %0
+  dealloc_stack %0
+  %12 = tuple ()
+  return %12
+}
+
+// Test that LifetimeDependence.Scope.computeRange handles a singly-initialized alloc_stack of trivial type by treating
+// it as available for the entire function
+sil [ossa] @testTrivialStackInit : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_stack [lexical] [var_decl] $TrivialHolder, let, name "v"
+  %1 = function_ref @initTrivialHolder : $@convention(thin) () -> @out TrivialHolder
+  %2 = apply %1(%0) : $@convention(thin) () -> @out TrivialHolder
+  %3 = function_ref @getTrivialNE : $@convention(thin) (@in_guaranteed TrivialHolder) -> @lifetime(borrow 0) @owned NE
+  %4 = apply %3(%0) : $@convention(thin) (@in_guaranteed TrivialHolder) -> @lifetime(borrow 0) @owned NE
+  %5 = mark_dependence [unresolved] %4 on %0
+  dealloc_stack %0
+  %6 = move_value [var_decl] %5
+  %7 = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %8 = apply %7(%6) : $@convention(thin) (@guaranteed NE) -> ()
+  destroy_value %6
+  %12 = tuple ()
+  return %12
+}
+
+// Test that a borrowed dependency cannot inherit a copied dependency.
+sil [ossa] @testReborrow : $@convention(thin) (@guaranteed NE) -> @lifetime(copy 0) @owned NE {
+bb0(%0 : @guaranteed $NE):
+  debug_value %0, let, name "ne", argno 1
+  %2 = function_ref @reborrowNE : $@convention(thin) (@guaranteed NE) -> @lifetime(borrow 0) @owned NE
+  %3 = apply %2(%0) : $@convention(thin) (@guaranteed NE) -> @lifetime(borrow 0) @owned NE
+  // expected-error @-1{{lifetime-dependent value escapes its scope}}
+  // expected-note @-6{{it depends on the lifetime of an argument of 'testReborrow'}}
+  %4 = mark_dependence [unresolved] %3 on %0
+  return %4 // expected-note {{this use causes the lifetime-dependent value to escape}}
+}
+
+sil [ossa] @testBorrowValue : $@convention(thin) (@guaranteed NE) -> @lifetime(copy 0) @owned NE {
+bb0(%0 : @guaranteed $NE):
+  %2 = function_ref @reborrowNE : $@convention(thin) (@guaranteed NE) -> @lifetime(borrow 0) @owned NE
+  %3 = apply %2(%0) : $@convention(thin) (@guaranteed NE) -> @lifetime(borrow 0) @owned NE
+  // expected-error @-1{{lifetime-dependent value escapes its scope}}
+  // expected-note @-5{{it depends on the lifetime of an argument of 'testBorrowValue'}}
+  %4 = mark_dependence [unresolved] %3 on %0
+  return %4 // expected-note {{this use causes the lifetime-dependent value to escape}}
+}
+
+// Test a borrowed dependency on an address
+sil [ossa] @testBorrowAddress : $@convention(thin) <T where T : ~Escapable> (@thick T.Type) -> @lifetime(immortal) @out T {
+bb0(%0 : $*T, %1 : $@thick T.Type):
+  debug_value %1, let, name "type", argno 1
+  %3 = alloc_stack [lexical] [var_decl] $Holder, var, name "holder", type $Holder
+  %4 = metatype $@thin Holder.Type
+
+  %5 = function_ref @makeHolder : $@convention(method) (@thin Holder.Type) -> @owned Holder
+  %6 = apply %5(%4) : $@convention(method) (@thin Holder.Type) -> @owned Holder
+  store %6 to [init] %3
+  %8 = alloc_stack [lexical] [var_decl] $T, let, name "result"
+  // expected-error @-1{{lifetime-dependent value escapes its scope}}
+  %9 = begin_access [read] [static] %3
+  // expected-note  @-1{{it depends on this scoped access to variable}}
+  %10 = load [copy] %9
+
+  %11 = function_ref @getGeneric : $@convention(thin) <τ_0_0 where τ_0_0 : ~Escapable> (@guaranteed Holder, @thick τ_0_0.Type) -> @lifetime(borrow 0) @out τ_0_0
+  %12 = apply %11<T>(%8, %10, %1) : $@convention(thin) <τ_0_0 where τ_0_0 : ~Escapable> (@guaranteed Holder, @thick τ_0_0.Type) -> @lifetime(borrow 0) @out τ_0_0
+  mark_dependence_addr [unresolved] %8 on %9
+  destroy_value %10
+  copy_addr %8 to [init] %0
+  // expected-note @-1{{this use causes the lifetime-dependent value to escape}}
+  end_access %9
+  destroy_addr %8
+  dealloc_stack %8
+  destroy_addr %3
+  dealloc_stack %3
+  %21 = tuple ()
+  return %21
+}
+
+// Test VariableDefUseWalker: initialization with copy_addr.
+sil shared [thunk] [ossa] @testCopyInit : $@convention(thin) (@in_guaranteed Holder) -> @out NE {
+bb0(%0 : $*NE, %1 : $*Holder):
+  %2 = alloc_stack $Holder
+  copy_addr %1 to [init] %2
+  %4 = load [take] %2
+  %5 = alloc_stack $Holder
+  %6 = store_borrow %4 to %5
+  %7 = alloc_stack $NE // expected-error {{lifetime-dependent value escapes its scope}}
+  // expected-note @-8{{it depends on the lifetime of an argument of 'testCopyInit'}}
+
+  %8 = function_ref @getNEIndirect : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address_for_deps 0) @out NE
+  %9 = apply %8(%7, %6) : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address_for_deps 0) @out NE
+  mark_dependence_addr [unresolved] %7 on %6
+  %11 = load [take] %7
+  store %11 to [init] %0 // expected-note {{this use causes the lifetime-dependent value to escape}}
+  end_borrow %6
+  dealloc_stack %7
+  dealloc_stack %5
+  destroy_value %4
+  dealloc_stack %2
+  %18 = tuple ()
+  return %18
+}
+
+// Test a address dependency on a trivial value temporarily copied to the stack. The value's addressable range only
+// extends to the dealloc_stack.
+//
+// SILGen should never generate temporary stack copies for addressable dependencies, but we need to diagnose them anyway
+// so that a SILGen bug does not become a miscompile. Furthermore, LifetimeDependenceScopeFixup now automatically
+// extends such local allocations, so this diagnostic only fires on source-level tests when scope extension is
+// impossible.
+//
+// rdar://159680262 ([nonescapable] diagnose dependence on a temporary copy of a global array)
+sil hidden [noinline] [ossa] @testTempTrivialStackCopy : $@convention(thin) () -> () {
+bb0:
+  %0 = function_ref @globalAddress : $@convention(thin) () -> Builtin.RawPointer
+  %1 = apply %0() : $@convention(thin) () -> Builtin.RawPointer
+  %2 = pointer_to_address %1 to [strict] $*InlineInt
+  %3 = begin_access [read] [dynamic] %2 // expected-note{{it depends on this scoped access to variable ''}}
+  %4 = load [trivial] %3
+  end_access %3
+  %6 = alloc_stack $InlineInt
+  store %4 to [trivial] %6
+
+  %8 = function_ref @addressInt : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address_for_deps 0) @owned Span<Int>
+  %9 = apply %8(%6) : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address_for_deps 0) @owned Span<Int>
+  %10 = mark_dependence [unresolved] %9 on %6
+  %11 = move_value [var_decl] %10 // expected-error{{lifetime-dependent value escapes its scope}}
+  dealloc_stack %6
+  %13 = begin_borrow %11
+
+  %14 = function_ref @useSpan : $@convention(thin) (@guaranteed Span<Int>) -> ()
+  %15 = apply %14(%13) : $@convention(thin) (@guaranteed Span<Int>) -> ()
+  end_borrow %13
+  destroy_value %11 // expected-note{{this use of the lifetime-dependent value is out of scope}}
+  %18 = tuple ()
+  return %18
+}
+
+// Test an address dependency on a trivial value temporarily copied to the stack. The value's addressable range only
+// extends to the dealloc_stack. This represents the SIL from @testTempTrivialStackCopy after
+// LifetimeDependenceScopeFixup has extended the local allocation.
+sil hidden [noinline] [ossa] @testExtendedTrivialStackCopy : $@convention(thin) () -> () {
+bb0:
+  %0 = function_ref @globalAddress : $@convention(thin) () -> Builtin.RawPointer
+  %1 = apply %0() : $@convention(thin) () -> Builtin.RawPointer
+  %2 = pointer_to_address %1 to [strict] $*InlineInt
+  %3 = begin_access [read] [dynamic] %2
+  %4 = load [trivial] %3
+  end_access %3
+  %6 = alloc_stack $InlineInt
+  store %4 to [trivial] %6
+
+  %8 = function_ref @addressInt : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address_for_deps 0) @owned Span<Int>
+  %9 = apply %8(%6) : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address_for_deps 0) @owned Span<Int>
+  %10 = mark_dependence [unresolved] %9 on %6
+  %11 = move_value [var_decl] %10
+  %13 = begin_borrow %11
+
+  %14 = function_ref @useSpan : $@convention(thin) (@guaranteed Span<Int>) -> ()
+  %15 = apply %14(%13) : $@convention(thin) (@guaranteed Span<Int>) -> ()
+  end_borrow %13
+  destroy_value %11
+  dealloc_stack %6
+  %18 = tuple ()
+  return %18
+}
+
+// Test two address dependencies on the same temporay. The first dependency is addressable; it's uses are covered by the
+// stack allocation. The second dependency is non-addressable; it's uses are not covered by the stack allocation. So,
+// this is correct SIL but is falsely diagnosed as a lifetime error. This conservative error is fine because SILGen
+// never reuses a temporary allocaiton for both an addressable and non-addressable dependency.
+sil hidden [noinline] [ossa] @testFalseTempTrivialStackCopy : $@convention(thin) (Int) -> () {
+bb0(%0: $Int):
+  %1 = alloc_stack $Int
+  store %0 to [trivial] %1
+
+  %3 = function_ref @addressOfInt : $@convention(thin) (@in_guaranteed Int) -> @lifetime(borrow address 0) @owned Span<Int>
+  %4 = apply %3(%1) : $@convention(thin) (@in_guaranteed Int) -> @lifetime(borrow address 0) @owned Span<Int>
+  %5 = mark_dependence [unresolved] %4 on %1
+  %6 = move_value [var_decl] %5
+  destroy_value %6
+
+  %8 = function_ref @noAddressInt : $@convention(thin) (@in_guaranteed Int) -> @lifetime(borrow 0) @owned Span<Int>
+  %9 = apply %8(%1) : $@convention(thin) (@in_guaranteed Int) -> @lifetime(borrow 0) @owned Span<Int>
+  %10 = mark_dependence [unresolved] %9 on %1
+  %11 = move_value [var_decl] %10 // expected-error{{lifetime-dependent value escapes its scope}}
+  // expected-note@-15{{it depends on the lifetime of an argument of 'testFalseTempTrivialStackCopy'}}
+
+  dealloc_stack %1
+
+  %13 = begin_borrow %11
+  %14 = function_ref @useSpan : $@convention(thin) (@guaranteed Span<Int>) -> ()
+  %15 = apply %14(%13) : $@convention(thin) (@guaranteed Span<Int>) -> ()
+  end_borrow %13
+  destroy_value %11 // expected-note{{this use of the lifetime-dependent value is out of scope}}
+  %18 = tuple ()
+  return %18
+}
+
+// Test dependence on the temporary stack address of a trivial value. computeAddressableRange must extend the lifetime
+// of %tempAddr into the unreachable.
+sil hidden [ossa] @testTempAddressUnreachable : $@convention(thin) (@in_guaranteed InlineInt) -> () {
+bb0(%0 : $*InlineInt):
+  %loadArg = load [trivial] %0
+  %tempAddr = alloc_stack $InlineInt
+  store %loadArg to [trivial] %tempAddr
+
+  %f1 = function_ref @getInlineSpan : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address 0) @owned RawSpan
+  %call = apply %f1(%tempAddr) : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address 0) @owned RawSpan
+  %md = mark_dependence [unresolved] %call on %tempAddr
+
+  %f2 = function_ref @useRawSpan : $@convention(thin) (@guaranteed RawSpan) -> @error any Error
+  try_apply %f2(%md) : $@convention(thin) (@guaranteed RawSpan) -> @error any Error, normal bb1, error bb2
+
+bb1(%void : $()):
+  destroy_value %md
+  dealloc_stack %tempAddr
+  %99 = tuple ()
+  return %99
+
+bb2(%error : @owned $any Error):
+  destroy_value [dead_end] %md
+  unreachable
+}
+
+// Test dependence on the temporary stack address of a trivial value. computeAddressableRange must extend the lifetime
+// of %tempAddr into the unreachable.
+//
+// Note that the computed instruction range is marked Invalid because it does not have a single dominating
+// block. Nonetheless, the range still include all blocks in which the stack allocation is live, which is all we care
+// about.
+sil hidden [ossa] @testTempAddressNondominatedUnreachable : $@convention(thin) (@in_guaranteed InlineInt) -> () {
+bb0(%0 : $*InlineInt):
+  cond_br undef, bb1, bb2
+
+bb1:
+  br bb5
+
+bb2:
+  %loadArg = load [trivial] %0
+  %tempAddr = alloc_stack $InlineInt
+  store %loadArg to [trivial] %tempAddr
+
+  %f1 = function_ref @getInlineSpan : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address 0) @owned RawSpan
+  %call = apply %f1(%tempAddr) : $@convention(thin) (@in_guaranteed InlineInt) -> @lifetime(borrow address 0) @owned RawSpan
+  %md = mark_dependence [unresolved] %call on %tempAddr
+
+  %f2 = function_ref @useRawSpan : $@convention(thin) (@guaranteed RawSpan) -> @error any Error
+  try_apply %f2(%md) : $@convention(thin) (@guaranteed RawSpan) -> @error any Error, normal bb3, error bb4
+
+bb3(%void : $()):
+  destroy_value %md
+  dealloc_stack %tempAddr
+  %99 = tuple ()
+  return %99
+
+bb4(%error : @owned $any Error):
+  destroy_value [dead_end] %md
+  br bb5
+
+bb5:
+  unreachable
+}
diff --git a/test/SILOptimizer/lifetime_dependence/verify_diagnostics.swift b/test/SILOptimizer/lifetime_dependence/verify_diagnostics.swift
new file mode 100644
index 0000000000000..2177a91345ec7
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/verify_diagnostics.swift
@@ -0,0 +1,411 @@
+// RUN: %target-swift-frontend -primary-file %s -parse-as-library -emit-sil \
+// RUN:   -o /dev/null \
+// RUN:   -verify \
+// RUN:   -sil-verify-all \
+// RUN:   -enable-builtin-module \
+// RUN:   -module-name test \
+// RUN:   -define-availability "Span 0.1:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999" \
+// RUN:   -enable-experimental-feature Lifetimes \
+// RUN:   -enable-experimental-feature AddressableParameters
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_AddressableParameters
+
+// Test diagnostic output for interesting corner cases. Similar to semantics.swift, but this tests corner cases in the
+// implementation as opposed to basic language rules.
+
+import Builtin
+
+struct Borrow<T: ~Copyable>: Copyable, ~Escapable {
+  let pointer: UnsafePointer<T>
+
+  @_lifetime(borrow value)
+  init(_ value: borrowing @_addressable T) {
+    pointer = UnsafePointer(Builtin.unprotectedAddressOfBorrow(value))
+  }
+
+  subscript() -> T {
+    unsafeAddress {
+      pointer
+    }
+  }
+}
+
+struct A {}
+
+func useA(_:A){}
+
+public struct NE : ~Escapable {}
+
+public struct NEImmortal: ~Escapable {
+  @_lifetime(immortal)
+  public init() {}
+}
+
+class C {}
+
+struct Holder {
+  var c: C? = nil
+}
+
+// Generic non-Escapable for indirect values.
+struct GNE<T> : ~Escapable {
+  let t: T
+  @_lifetime(borrow t)
+  init(t: borrowing T) { self.t = copy t }
+}  
+
+@_silgen_name("forward")
+@_lifetime(copy arg)
+func forward<T>(_ arg: GNE<T>) -> GNE<T>
+
+@_silgen_name("getGeneric")
+@_lifetime(borrow holder)
+func getGeneric<T: ~Escapable>(_ holder: borrowing Holder, _: T.Type) -> T
+
+func mutate(_: inout Holder) {}
+
+// Test that conditionally returning an Optional succeeds.
+//
+// See scope_fixup.sil: testReturnPhi.
+@available(Span 0.1, *)
+extension Array {
+  @_lifetime(&self)
+  mutating func getOptionalMutableSpan() -> MutableSpan<Element>? {
+    if count == 0 {
+      return nil
+    }
+    return mutableSpan
+  }
+}
+
+// Test that returning an immutable Span from an inout Array.
+//
+// See scope_fixup.sil: testNestedModRead.
+@available(Span 0.1, *)
+@inline(never)
+@_lifetime(&array)
+func getImmutableSpan(_ array: inout [Int]) -> Span<Int> {
+ return array.span
+}
+
+struct NCInt: ~Copyable {
+  var i: Int
+
+  @_lifetime(borrow self)
+  func getNE() -> NEInt {
+    NEInt(owner: self)
+  }
+}
+
+public struct NEInt: ~Escapable {
+  var i: Int
+
+  @_lifetime(borrow owner)
+  init(owner: borrowing NCInt) {
+    self.i = owner.i
+  }
+
+  @_lifetime(immortal)
+  init(immortal i: Int) {
+    self.i = i
+  }
+}
+
+struct TestDeinitCallsAddressor: ~Copyable, ~Escapable {
+  let a: Borrow<A>
+
+  deinit {
+    useA(a[])
+  }
+}
+
+struct NCBuffer: ~Copyable {
+  fileprivate let buffer: UnsafeMutableRawBufferPointer
+
+  public init() {
+    let ptr = UnsafeMutableRawPointer.init(bitPattern: 0)
+    self.buffer = UnsafeMutableRawBufferPointer(start: ptr, count: 0)
+  }
+
+  public var bytes: Span<UInt8> {
+    @_lifetime(borrow self)
+    borrowing get {
+      let span: Span<UInt8> = Span(_bytes: self.buffer.bytes)
+      return span
+    }
+  }
+}
+
+// Test a borrowed dependency on an address
+@_lifetime(immortal)
+public func testGenericDep<T: ~Escapable>(type: T.Type) -> T {
+  let holder = Holder()
+  let result = getGeneric(holder, type)
+  // expected-error @-1{{lifetime-dependent variable 'result' escapes its scope}}
+  // expected-note  @-3{{it depends on the lifetime of variable 'holder'}}
+  return result
+  // expected-note @-1{{this use causes the lifetime-dependent value to escape}}
+}
+
+// Test diagnostics on implicit accessors.
+public struct ImplicitAccessors {
+  let c: C
+
+  public var neComputed: NEImmortal {
+    get {
+      NEImmortal()
+    }
+    set {
+    }
+  }
+}
+
+public struct NoncopyableImplicitAccessors : ~Copyable & ~Escapable {
+  public var ne: NE
+
+  public var neComputedBorrow: NE {
+    @_lifetime(borrow self)
+    get { ne }
+
+    @_lifetime(self: copy newValue)
+    set {
+      ne = newValue
+    }
+  }
+}
+
+struct HasMethods {
+  @_lifetime(borrow self)
+  func data(index: Int) -> NEImmortal {
+    NEImmortal()
+  }
+}
+
+func testClosureCapture1(_ a: HasMethods) {
+  let fn = a.data
+  // expected-error @-1{{lifetime-dependent value escapes its scope}}
+  // expected-note  @-2{{it depends on a closure capture; this is not yet supported}}
+  // expected-note  @-3{{this use causes the lifetime-dependent value to escape}}
+  _ = consume fn
+
+  let fn2 = a.data(index:)
+  // expected-error @-1{{lifetime-dependent value escapes its scope}}
+  // expected-note  @-2{{it depends on a closure capture; this is not yet supported}}
+  // expected-note  @-3{{this use causes the lifetime-dependent value to escape}}
+  _ = consume fn2
+
+  // FIXME: rdar://150073405 ([SILGen] support synthesized _modify on top of borrowed getters with library evolution)
+  //
+  // withUnsafePointer is disabled because it generates a reabstraction thunk, which is impossible to diagenose.
+  /*
+  withUnsafePointer(to: a.data) { fptr in
+    // future-error @-1{{lifetime-dependent value escapes its scope}}
+    // future-note  @-2{{it depends on a closure capture; this is not yet supported}}
+    // future-note  @-3{{this use causes the lifetime-dependent value to escape}}
+    }
+   */
+}
+
+public struct InlineInt: BitwiseCopyable {
+  var val: UInt64
+
+  var span: RawSpan {
+    @_addressableSelf
+    @_lifetime(borrow self) borrowing get {
+      let buf = UnsafeRawBufferPointer(start: UnsafeRawPointer(Builtin.addressOfBorrow(val)), count: 1)
+      let span = RawSpan(_unsafeBytes: buf)
+      return unsafe _overrideLifetime(span, borrowing: val)
+    }
+  }
+}
+
+// =============================================================================
+// Indirect ~Escapable results
+// =============================================================================
+
+@_lifetime(copy arg1)
+func testIndirectForwardedResult<T>(arg1: GNE<T>) -> GNE<T> {
+  forward(arg1)
+}
+
+@_lifetime(copy arg1)
+func testIndirectNonForwardedResult<T>(arg1: GNE<T>, arg2: GNE<T>) -> GNE<T> {
+  // expected-error @-1{{lifetime-dependent variable 'arg2' escapes its scope}}
+  // expected-note  @-2{{it depends on the lifetime of argument 'arg2'}}
+  forward(arg2) // expected-note {{this use causes the lifetime-dependent value to escape}}
+}
+
+func testIndirectClosureResult<T>(f: () -> GNE<T>) -> GNE<T> {
+  f()
+  // expected-error @-1{{lifetime-dependent variable '$return_value' escapes its scope}}
+  // expected-note  @-3{{it depends on the lifetime of argument '$return_value'}}
+  // expected-note  @-3{{this use causes the lifetime-dependent value to escape}}
+}
+
+// =============================================================================
+// Coroutines
+// =============================================================================
+
+// Test _read of a noncopyable type with a dead-end (end_borrow)
+//
+// rdar://153479358 (Compiler crash when force-unwrapping optional ~Copyable type)
+class ClassStorage {
+  private var nc: NCInt?
+
+  init(nc: consuming NCInt?) {
+    self.nc = nc
+  }
+
+  func readNoncopyable() {
+    let ne = self.nc!.getNE()
+    _ = ne
+  }
+}
+
+// =============================================================================
+// Immortal
+// =============================================================================
+
+@_lifetime(immortal)
+func testVoid() -> NEInt {
+  let ne = NEInt(immortal: 3)
+  return _overrideLifetime(ne, borrowing: ())
+}
+
+// =============================================================================
+// Optional
+// =============================================================================
+
+// A view that contains some arbitrary opaque type, making it address-only, but also depends on an unsafe pointer.
+public struct AddressOnlyMutableView<T> : ~Copyable, ~Escapable {
+  let t: T
+
+  // placeholder
+  @_lifetime(borrow holder)
+  init(holder: borrowing Holder, t: T) { self.t = t }
+
+  mutating func modify() {}
+}
+
+// Return an address-only optional view (requiring switch_enum_addr).
+@_silgen_name("addressOnlyMutableView")
+@_lifetime(&holder)
+func addressOnlyMutableView<T>(holder: inout Holder, with t: T) -> AddressOnlyMutableView<T>?
+
+// rdar://151231236 ([~Escapable] Missing 'overlapping acceses' error when called from client code, but exact same code
+// produces error in same module)
+//
+// Extend the access scope for &holder across the switch_enum_addr required to unwrap Optional<AddressOnlyMutableView>.
+func testSwitchAddr<T>(holder: inout Holder, t: T) {
+  // mutableView must be a 'var' to require local variable data flow.
+  var mutableView = addressOnlyMutableView(holder: &holder, with: t)! // expected-error {{overlapping accesses to 'holder', but modification requires exclusive access; consider copying to a local variable}}
+  mutate(&holder) // expected-note {{conflicting access is here}}
+  mutableView.modify()
+}
+
+// =============================================================================
+// Throwing
+// =============================================================================
+
+@available(Span 0.1, *)
+func mutableSpanMayThrow(_: borrowing MutableSpan<Int>) throws {}
+
+@available(Span 0.1, *)
+func testSpanMayThrow(buffer: inout [Int]) {
+  let bufferSpan = buffer.mutableSpan
+  try! mutableSpanMayThrow(bufferSpan)
+}
+
+// =============================================================================
+// inout
+// =============================================================================
+
+@available(Span 0.1, *)
+func inoutToImmortal(_ s: inout RawSpan) {
+  let tmp = RawSpan(_unsafeBytes: UnsafeRawBufferPointer(start: nil, count: 0))
+  s = _overrideLifetime(tmp, borrowing: ())
+}
+
+// =============================================================================
+// addressable dependencies
+// =============================================================================
+
+@available(Span 0.1, *)
+var values: InlineArray<_, Int> = [0, 1, 2]
+
+@available(Span 0.1, *)
+func getValues() -> InlineArray<3, Int> { values }
+
+// Test a trivial global variable used by addressableForDependencies (InlineArray.span). This either requires a direct address
+// to the global or it requires extension of the local stack allocation by LifetimeDependenceScopeFixup.
+//
+// rdar://159680262 ([nonescapable] diagnose dependence on a temporary copy of a global array)
+@available(Span 0.1, *)
+func readGlobalSpan() -> Int {
+  let span = values.span
+  return span[3]
+}
+
+// Test a trivial global variable used by addressableForDependencies (InlineArray.span).
+//
+// TODO: This will no longer be an error when SILGen passes a direct address to the global instead of a temporary stack
+// allocation: rdar://151320168 ([nonescapable] support immortal span over global array)
+@available(Span 0.1, *)
+@_lifetime(immortal)
+func returnGlobalSpan() -> Span<Int> {
+  let span = values.span // expected-error{{lifetime-dependent variable 'span' escapes its scope}}
+  // expected-note@-1{{it depends on this scoped access to variable 'values'}}
+  return span // expected-note{{this use causes the lifetime-dependent value to escape}}
+}
+
+// Test a trivial temporary stack allocation used by addressableForDependencies
+// (InlineArray.span). LifetimeDependenceScopeFixup needs to extend the local stack allocation.
+@available(Span 0.1, *)
+func readTempSpan() -> Int {
+  let span = getValues().span
+  return span[3]
+}
+
+// Test a trivial temporary stack allocation used by addressableForDependencies (InlineArray.span). This illegally
+// returns an address into a temporary.
+@available(Span 0.1, *)
+@_lifetime(immortal)
+func returnTempSpan() -> Span<Int> {
+  let span = getValues().span // expected-error{{lifetime-dependent variable 'span' escapes its scope}}
+  // expected-note@-1{{it depends on the lifetime of this parent value}}
+  return span // expected-note{{this use causes the lifetime-dependent value to escape}}
+}
+
+// Test a trivial temporary stack allocation used by an addressable parameter
+// (Borrow.init). LifetimeDependenceScopeFixup needs to extend the local stack allocation.
+@available(Span 0.1, *)
+func readTempBorrow() -> Int {
+  let borrow = Borrow(3)
+  return borrow[]
+}
+
+// Test a trivial temporary stack allocation used by an addressable parameter (Borrow.init). This illegally returns an
+// address into a temporary.
+@available(Span 0.1, *)
+@_lifetime(immortal)
+func returnTempBorrow() -> Borrow<Int> {
+  let span = Borrow(3) // expected-error{{lifetime-dependent variable 'span' escapes its scope}}
+  // expected-note@-1{{it depends on the lifetime of this parent value}}
+  return span // expected-note{{this use causes the lifetime-dependent value to escape}}
+}
+
+// Test dependence on the temporary stack address of a trivial value. computeAddressableRange must extend the lifetime
+// of 'inline' into the unreachable.
+//
+// This test requires InlineInt to be a trivial value defined in this module so that inline.span generates:
+//
+//     %temp = alloc_stack
+//     store %arg to [trivial] temp
+//     apply %get_span(%temp)
+//
+// If we use InlineArray instead, we get a store_borrow, which is a completely different situation.
+func test(inline: InlineInt) {
+  inline.span.withUnsafeBytes { _ = $0 }
+}
diff --git a/test/SILOptimizer/lifetime_dependence/verify_library_diagnostics.swift b/test/SILOptimizer/lifetime_dependence/verify_library_diagnostics.swift
new file mode 100644
index 0000000000000..15d39a5f37633
--- /dev/null
+++ b/test/SILOptimizer/lifetime_dependence/verify_library_diagnostics.swift
@@ -0,0 +1,58 @@
+// RUN: %target-swift-frontend %s -emit-module -emit-module-interface-path %t/test.swiftmodule \
+// RUN:   -swift-version 5 \
+// RUN:   -o /dev/null \
+// RUN:   -enable-library-evolution \
+// RUN:   -verify \
+// RUN:   -sil-verify-all \
+// RUN:   -enable-builtin-module \
+// RUN:   -module-name test \
+// RUN:   -define-availability "Span 0.1:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999" \
+// RUN:   -enable-experimental-feature Lifetimes \
+// RUN:   -enable-experimental-feature AddressableParameters
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_AddressableParameters
+
+// Test diagnostic output for interesting corner cases. Similar to semantics.swift, but this tests corner cases in the
+// implementation as opposed to basic language rules.
+
+import Builtin
+
+public struct NE : ~Escapable {
+}
+
+public struct NEImmortal: ~Escapable {
+  @_lifetime(immortal)
+  public init() {}
+}
+
+class C {}
+
+// Test that we don't implicitly try to create a keypath getter, since
+// ~Escapable types are not yet supported by keypaths.
+public struct ImplicitAccessors {
+  let c: C
+
+  public var neComputed: NEImmortal {
+    get {
+      NEImmortal()
+    }
+    set {
+    }
+  }
+}
+
+public struct NoncopyableImplicitAccessors : ~Copyable & ~Escapable {
+  public var ne: NE
+
+  public var neComputedBorrow: NE {
+    @_lifetime(borrow self)
+    get { ne }
+
+    @_lifetime(self: copy newValue)
+    set {
+      ne = newValue
+    }
+  }
+}
diff --git a/test/SILOptimizer/liveness_unit.sil b/test/SILOptimizer/liveness_unit.sil
index 472b8fe8bb4eb..f59659aeff7f0 100644
--- a/test/SILOptimizer/liveness_unit.sil
+++ b/test/SILOptimizer/liveness_unit.sil
@@ -231,7 +231,7 @@ bb4(%phi : @owned $C):
 // CHECK-NEXT: bb2: LiveOut
 // CHECK-NEXT: bb1: LiveOut
 // CHECK: ref_element_addr %7 : $D, #D.object
-// CHECK-NEXT-LABEL: end running test 1 of 1 on testSSADeadRefElementAddr: ssa_liveness
+// CHECK: end running test 1 of 1 on testSSADeadRefElementAddr: ssa_liveness
 sil [ossa] @testSSADeadRefElementAddr : $@convention(thin) (@guaranteed C) -> () {
 bb0(%0 : @guaranteed $C):
   specify_test "ssa_liveness @argument[0]"
diff --git a/test/SILOptimizer/lower_hop_to_actor.sil b/test/SILOptimizer/lower_hop_to_actor.sil
index c24e5888ee7f6..c594b5b142dc8 100644
--- a/test/SILOptimizer/lower_hop_to_actor.sil
+++ b/test/SILOptimizer/lower_hop_to_actor.sil
@@ -307,3 +307,17 @@ bb0(%0 : @guaranteed $Optional<any Actor>):
   return %r
 }
 
+// CHECK-LABEL: sil [ossa] @optional_none :
+// CHECK:         %0 = enum
+// CHECK-NEXT:    %1 = begin_borrow %0
+// CHECK-NEXT:    switch_enum %1
+// CHECK:         mark_dependence
+// CHECK-NEXT:    end_borrow %1
+// CHECKL:      } // end sil function '@optional_none'
+sil [ossa] @optional_none : $@convention(thin) @async () -> () {
+bb0:
+  %0 = enum $Optional<any Actor>, #Optional.none!enumelt
+  hop_to_executor %0
+  %r = tuple ()
+  return %r
+}
diff --git a/test/SILOptimizer/mandatory_inlining_circular_inline_always.sil b/test/SILOptimizer/mandatory_inlining_circular_inline_always.sil
new file mode 100644
index 0000000000000..a2f7f9d0ef950
--- /dev/null
+++ b/test/SILOptimizer/mandatory_inlining_circular_inline_always.sil
@@ -0,0 +1,26 @@
+// RUN: %target-sil-opt -enable-sil-verify-all %s -inline-always-inlining -verify
+
+import Builtin
+import Swift
+
+sil [always_inline] @test_circular_foo : $@convention(thin) (Float32) -> Float32 {
+bb0(%0 : $Float32):
+  %3 = function_ref @test_circular_bar : $@convention(thin) (Float32) -> Float32
+  %5 = apply %3(%0) : $@convention(thin) (Float32) -> Float32 // expected-error {{inlining '@inline(always)' functions forms circular loop}} expected-note 2 {{while inlining here}}
+  return %5 : $Float32
+}
+
+sil [always_inline] @test_circular_bar : $@convention(thin) (Float32) -> Float32 {
+bb0(%0 : $Float32):
+  %3 = function_ref @test_circular_baz : $@convention(thin) (Float32) -> Float32
+  %5 = apply %3(%0) : $@convention(thin) (Float32) -> Float32 // expected-error {{inlining '@inline(always)' functions forms circular loop}} expected-note 2 {{while inlining here}}
+  return %5 : $Float32
+}
+
+sil [always_inline] @test_circular_baz : $@convention(thin) (Float32) -> Float32 {
+bb0(%0 : $Float32):
+  %3 = function_ref @test_circular_foo : $@convention(thin) (Float32) -> Float32
+  %5 = apply %3(%0) : $@convention(thin) (Float32) -> Float32 // expected-error {{inlining '@inline(always)' functions forms circular loop}} expected-note 2 {{while inlining here}}
+  return %5 : $Float32
+}
+
diff --git a/test/SILOptimizer/mandatory_inlining_circular_inline_always.swift b/test/SILOptimizer/mandatory_inlining_circular_inline_always.swift
new file mode 100644
index 0000000000000..c0f4eb6caeeec
--- /dev/null
+++ b/test/SILOptimizer/mandatory_inlining_circular_inline_always.swift
@@ -0,0 +1,12 @@
+// RUN: %target-swift-frontend -enable-experimental-feature InlineAlways -sil-verify-all -emit-sil %s -o /dev/null -verify
+
+// REQUIRES: swift_feature_InlineAlways
+
+@inline(always) func mutally(_ x: Double) -> Double {
+  return recursive(x); // expected-error {{inlining '@inline(always)' functions forms circular loop}} expected-note 1 {{while inlining here}}
+}
+
+@inline(always) func recursive(_ x: Double) -> Double {
+  return mutally(x); // expected-error {{inlining '@inline(always)' functions forms circular loop}} expected-note 1 {{while inlining here}}
+}
+
diff --git a/test/SILOptimizer/mandatory_inlining_inline_always.sil b/test/SILOptimizer/mandatory_inlining_inline_always.sil
new file mode 100644
index 0000000000000..c8db0df8a42ed
--- /dev/null
+++ b/test/SILOptimizer/mandatory_inlining_inline_always.sil
@@ -0,0 +1,153 @@
+// RUN: env DYLD_INSERT_LIBRARIES=/usr/lib/libgmalloc.dylib %target-sil-opt -sil-print-types -enable-objc-interop -module-name A -enable-sil-verify-all %s -inline-always-inlining | %FileCheck %s
+
+// guardmalloc is incompatible with ASAN
+// REQUIRES: no_asan
+
+import Builtin
+import Swift
+
+sil @plus : $@convention(thin) (Int64, Int64) -> Int64
+sil @fromLiteral : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+
+
+// CHECK-LABEL: sil [always_inline] @test_add : $@convention(thin) (Int64) -> Int64 {
+sil [always_inline] @test_add : $@convention(thin) (Int64) -> Int64 {
+bb0(%0 : $Int64):
+  %1 = alloc_box ${ var Int64 }
+  %1a = project_box %1 : ${ var Int64 }, 0
+  store %0 to %1a : $*Int64
+  %3 = function_ref @plus : $@convention(thin) (Int64, Int64) -> Int64
+  %4 = load %1a : $*Int64
+  %5 = function_ref @fromLiteral : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %6 = metatype $@thin Int64.Type
+  %7 = integer_literal $Builtin.Int128, 20
+  %8 = apply %5(%7, %6) : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %9 = apply %3(%4, %8) : $@convention(thin) (Int64, Int64) -> Int64
+  strong_release %1 : ${ var Int64 }
+  return %9 : $Int64
+}
+
+// CHECK-LABEL: sil @inline_test_add : $@convention(thin) (Int64) -> Int64 {
+sil @inline_test_add : $@convention(thin) (Int64) -> Int64 {
+// CHECK: [[BB0:.*]]([[VAL0:%.*]] : $Int64):
+  // CHECK: [[VAL1:%.*]] = alloc_box ${ var Int64 }
+  // CHECK: [[PB1:%.*]] = project_box [[VAL1]]
+  // CHECK: store [[VAL0]] to [[PB1]]
+  // CHECK: [[VAL3:%.*]] = function_ref @plus
+  // CHECK: [[VAL4:%.*]] = function_ref @plus
+  // CHECK: [[VAL5:%.*]] = load [[PB1]]
+  // CHECK: [[VAL6:%.*]] = function_ref @fromLiteral
+  // CHECK: [[VAL7:%.*]] = metatype $@thin Int64.Type
+  // CHECK: [[VAL8:%.*]] = integer_literal $Builtin.Int128, 10
+  // CHECK: [[VAL9:%.*]] = apply [[VAL6]]([[VAL8]], [[VAL7]])
+  // CHECK: [[VAL10:%.*]] = apply [[VAL4]]([[VAL5]], [[VAL9]])
+  // CHECK: [[VAL11:%.*]] = alloc_box ${ var Int64 }
+  // CHECK: [[PB11:%.*]] = project_box [[VAL11]]
+  // CHECK: store [[VAL10]] to [[PB11]]
+  // CHECK: [[VAL13:%.*]] = function_ref @plus
+  // CHECK: [[VAL14:%.*]] = load [[PB11]]
+  // CHECK: [[VAL15:%.*]] = function_ref @fromLiteral
+  // CHECK: [[VAL16:%.*]] = metatype $@thin Int64.Type
+  // CHECK: [[VAL17:%.*]] = integer_literal $Builtin.Int128, 20
+  // CHECK: [[VAL18:%.*]] = apply [[VAL15]]([[VAL17]], [[VAL16]])
+  // CHECK: [[VAL19:%.*]] = apply [[VAL13]]([[VAL14]], [[VAL18]])
+  // CHECK: strong_release [[VAL11]]
+  // CHECK: [[VAL21:%.*]] = function_ref @fromLiteral
+  // CHECK: [[VAL22:%.*]] = metatype $@thin Int64.Type
+  // CHECK: [[VAL23:%.*]] = integer_literal $Builtin.Int128, 30
+  // CHECK: [[VAL24:%.*]] = apply [[VAL21]]([[VAL23]], [[VAL22]])
+  // CHECK: [[VAL25:%.*]] = apply [[VAL3]]([[VAL19]], [[VAL24]])
+  // CHECK: strong_release [[VAL1]]
+  // CHECK: return [[VAL25]]
+
+bb0(%0 : $Int64):
+  %1 = alloc_box ${ var Int64 }
+  %1a = project_box %1 : ${ var Int64 }, 0
+  store %0 to %1a : $*Int64
+  %3 = function_ref @plus : $@convention(thin) (Int64, Int64) -> Int64
+  %4 = function_ref @test_add : $@convention(thin) (Int64) -> Int64
+  %5 = function_ref @plus : $@convention(thin) (Int64, Int64) -> Int64
+  %6 = load %1a : $*Int64
+  %7 = function_ref @fromLiteral : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %8 = metatype $@thin Int64.Type
+  %9 = integer_literal $Builtin.Int128, 10
+  %10 = apply %7(%9, %8) : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %11 = apply %5(%6, %10) : $@convention(thin) (Int64, Int64) -> Int64
+  %12 = apply %4(%11) : $@convention(thin) (Int64) -> Int64
+  %13 = function_ref @fromLiteral : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %14 = metatype $@thin Int64.Type
+  %15 = integer_literal $Builtin.Int128, 30
+  %16 = apply %13(%15, %14) : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %17 = apply %3(%12, %16) : $@convention(thin) (Int64, Int64) -> Int64
+  strong_release %1 : ${ var Int64 }
+  return %17 : $Int64
+}
+
+// CHECK-LABEL: sil @inline_twice_test_add : $@convention(thin) (Int64) -> Int64 {
+sil @inline_twice_test_add : $@convention(thin) (Int64) -> Int64 {
+// CHECK: [[BB0:.*]]([[VAL0:%.*]] : $Int64):
+  // CHECK: [[VAL1:%.*]] = alloc_box ${ var Int64 }
+  // CHECK: [[PB1:%.*]] = project_box [[VAL1]]
+  // CHECK: store [[VAL0]] to [[PB1]]
+  // CHECK: [[VAL3:%.*]] = function_ref @plus
+  // CHECK: [[VAL4:%.*]] = function_ref @plus
+  // CHECK: [[VAL5:%.*]] = load [[PB1]]
+  // CHECK: [[VAL6:%.*]] = function_ref @fromLiteral
+  // CHECK: [[VAL7:%.*]] = metatype $@thin Int64.Type
+  // CHECK: [[VAL8:%.*]] = integer_literal $Builtin.Int128, 10
+  // CHECK: [[VAL9:%.*]] = apply [[VAL6]]([[VAL8]], [[VAL7]])
+  // CHECK: [[VAL10:%.*]] = apply [[VAL4]]([[VAL5]], [[VAL9]])
+  // CHECK: [[VAL11:%.*]] = alloc_box ${ var Int64 }
+  // CHECK: [[PB11:%.*]] = project_box [[VAL11]]
+  // CHECK: store [[VAL10]] to [[PB11]]
+  // CHECK: [[VAL13:%.*]] = function_ref @plus
+  // CHECK: [[VAL14:%.*]] = load [[PB11]]
+  // CHECK: [[VAL15:%.*]] = function_ref @fromLiteral
+  // CHECK: [[VAL16:%.*]] = metatype $@thin Int64.Type
+  // CHECK: [[VAL17:%.*]] = integer_literal $Builtin.Int128, 20
+  // CHECK: [[VAL18:%.*]] = apply [[VAL15]]([[VAL17]], [[VAL16]])
+  // CHECK: [[VAL19:%.*]] = apply [[VAL13]]([[VAL14]], [[VAL18]])
+  // CHECK: strong_release [[VAL11]]
+  // CHECK: [[VAL21:%.*]] = alloc_box ${ var Int64 }
+  // CHECK: [[PB21:%.*]] = project_box [[VAL21]]
+  // CHECK: store [[VAL19]] to [[PB21]]
+  // CHECK: [[VAL23:%.*]] = function_ref @plus
+  // CHECK: [[VAL24:%.*]] = load [[PB21]]
+  // CHECK: [[VAL25:%.*]] = function_ref @fromLiteral
+  // CHECK: [[VAL26:%.*]] = metatype $@thin Int64.Type
+  // CHECK: [[VAL27:%.*]] = integer_literal $Builtin.Int128, 20
+  // CHECK: [[VAL28:%.*]] = apply [[VAL25]]([[VAL27]], [[VAL26]])
+  // CHECK: [[VAL29:%.*]] = apply [[VAL23]]([[VAL24]], [[VAL28]])
+  // CHECK: strong_release [[VAL21]]
+  // CHECK: [[VAL31:%.*]] = function_ref @fromLiteral
+  // CHECK: [[VAL32:%.*]] = metatype $@thin Int64.Type
+  // CHECK: [[VAL33:%.*]] = integer_literal $Builtin.Int128, 30
+  // CHECK: [[VAL34:%.*]] = apply [[VAL31]]([[VAL33]], [[VAL32]])
+  // CHECK: [[VAL35:%.*]] = apply [[VAL3]]([[VAL29]], [[VAL34]])
+  // CHECK: strong_release [[VAL1]]
+  // CHECK: return [[VAL35]]
+
+bb0(%0 : $Int64):
+  %1 = alloc_box ${ var Int64 }
+  %1a = project_box %1 : ${ var Int64 }, 0
+  store %0 to %1a : $*Int64
+  %3 = function_ref @plus : $@convention(thin) (Int64, Int64) -> Int64
+  %4 = function_ref @test_add : $@convention(thin) (Int64) -> Int64
+  %5 = function_ref @test_add : $@convention(thin) (Int64) -> Int64
+  %6 = function_ref @plus : $@convention(thin) (Int64, Int64) -> Int64
+  %7 = load %1a : $*Int64
+  %8 = function_ref @fromLiteral : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %9 = metatype $@thin Int64.Type
+  %10 = integer_literal $Builtin.Int128, 10
+  %11 = apply %8(%10, %9) : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %12 = apply %6(%7, %11) : $@convention(thin) (Int64, Int64) -> Int64
+  %13 = apply %5(%12) : $@convention(thin) (Int64) -> Int64
+  %14 = apply %4(%13) : $@convention(thin) (Int64) -> Int64
+  %15 = function_ref @fromLiteral : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %16 = metatype $@thin Int64.Type
+  %17 = integer_literal $Builtin.Int128, 30
+  %18 = apply %15(%17, %16) : $@convention(thin) (Builtin.Int128, @thin Int64.Type) -> Int64
+  %19 = apply %3(%14, %18) : $@convention(thin) (Int64, Int64) -> Int64
+  strong_release %1 : ${ var Int64 }
+  return %19 : $Int64
+}
diff --git a/test/SILOptimizer/mandatory_inlining_open_existential.swift b/test/SILOptimizer/mandatory_inlining_open_existential.swift
index 2d558c00084ea..3b00b54a558d4 100644
--- a/test/SILOptimizer/mandatory_inlining_open_existential.swift
+++ b/test/SILOptimizer/mandatory_inlining_open_existential.swift
@@ -9,10 +9,10 @@ protocol P {
   func f() -> Self.Assoc
 }
 
-// CHECK-LABEL: sil hidden [always_inline] @$s35mandatory_inlining_open_existential6callee1pAA1P_pAaD_p_tF
+// CHECK-LABEL: sil hidden [heuristic_always_inline] @$s35mandatory_inlining_open_existential6callee1pAA1P_pAaD_p_tF
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access {{%[0-9]+}} : $*any P to $*[[OPENED_TY:@opened\("[-A-F0-9]+", any P\) Self]]
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $[[OPENED_TY]], #P.f : <Self where Self : P> (Self) -> () -> Self.Assoc
-// CHECK: [[RESULT:%[0-9]+]] = init_existential_addr {{%[0-9]+}} : $*any P, $[[OPENED_TY]].Assoc
+// CHECK: [[RESULT:%[0-9]+]] = init_existential_addr {{%[0-9]+}} : $*any P, $([[OPENED_TY]]).Assoc
 // CHECK: apply [[WITNESS]]<[[OPENED_TY]]>([[RESULT]], [[OPENED]])
 // CHECK: }
 @inline(__always)
@@ -23,7 +23,7 @@ func callee(p: any P) -> any P {
 // CHECK-LABEL: sil hidden @$s35mandatory_inlining_open_existential6caller1pAA1P_pAaD_p_tF
 // CHECK: [[OPENED:%[0-9]+]] = open_existential_addr immutable_access {{%[0-9]+}} : $*any P to $*[[OPENED_TY:@opened\("[-A-F0-9]+", any P\) Self]]
 // CHECK: [[WITNESS:%[0-9]+]] = witness_method $[[OPENED_TY]], #P.f : <Self where Self : P> (Self) -> () -> Self.Assoc
-// CHECK: [[RESULT:%[0-9]+]] = init_existential_addr {{%[0-9]+}} : $*any P, $[[OPENED_TY]].Assoc
+// CHECK: [[RESULT:%[0-9]+]] = init_existential_addr {{%[0-9]+}} : $*any P, $([[OPENED_TY]]).Assoc
 // CHECK: apply [[WITNESS]]<[[OPENED_TY]]>([[RESULT]], [[OPENED]])
 // CHECK: }
 func caller(p: any P) -> any P {
diff --git a/test/SILOptimizer/mandatory_inlining_ownership.sil b/test/SILOptimizer/mandatory_inlining_ownership.sil
index d71f14c598722..73adf0d336f1b 100644
--- a/test/SILOptimizer/mandatory_inlining_ownership.sil
+++ b/test/SILOptimizer/mandatory_inlining_ownership.sil
@@ -619,6 +619,41 @@ bb3:
   return %9999 : $()
 }
 
+sil [transparent] [ossa] @deinit_barrier : $@convention(thin) (@in_guaranteed Int) -> () {
+[global: deinit_barrier]
+bb0(%0 : $*Int):
+  %1 = tuple ()
+  return %1
+}
+
+sil [transparent] [ossa] @no_deinit_barrier : $@convention(thin) (@in_guaranteed Int) -> () {
+[global: ]
+bb0(%0 : $*Int):
+  %1 = tuple ()
+  return %1
+}
+
+// CHECK-LABEL: sil [ossa] @inline_deinit_barrier :
+// CHECK:         alloc_stack [lexical] $Int
+// CHECK:         alloc_stack $Int
+// CHECK:       } // end sil function 'inline_deinit_barrier'
+sil [ossa] @inline_deinit_barrier : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = alloc_stack $Int
+  store %0 to [trivial] %1
+  %2 = function_ref @deinit_barrier : $@convention(thin) (@in_guaranteed Int) -> ()
+  apply %2(%1) : $@convention(thin) (@in_guaranteed Int) -> ()
+  dealloc_stack %1
+
+  %10 = alloc_stack $Int
+  store %0 to [trivial] %10
+  %12 = function_ref @no_deinit_barrier : $@convention(thin) (@in_guaranteed Int) -> ()
+  apply %12(%10) : $@convention(thin) (@in_guaranteed Int) -> ()
+  dealloc_stack %10
+
+  %r = tuple ()
+  return %r
+}
 
 sil_vtable C2 {
   #C2.i!modify: (C2) -> () -> () : @devirt_callee
diff --git a/test/SILOptimizer/mandatory_perfopt_multimodule.swift b/test/SILOptimizer/mandatory_perfopt_multimodule.swift
new file mode 100644
index 0000000000000..eca029d0a6cd3
--- /dev/null
+++ b/test/SILOptimizer/mandatory_perfopt_multimodule.swift
@@ -0,0 +1,24 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -emit-module -parse-as-library -enable-library-evolution %t/module.swift -emit-module-path=%t/Module.swiftmodule -module-name=Module
+// RUN: %target-swift-frontend -emit-sil -o /dev/null -parse-as-library %t/main.swift -I%t -enable-experimental-feature SymbolLinkageMarkers
+
+// REQUIRES: swift_feature_SymbolLinkageMarkers
+
+// Check that this compiles successfully
+
+//--- module.swift
+
+public struct X: ~Copyable {
+  public init() {}
+  deinit {
+    print("deinit")
+  }
+}
+
+//--- main.swift
+
+import Module
+
+@_section("__TEXT,__mysection")
+var g: () -> () = { _ = X() }
diff --git a/test/SILOptimizer/mandatory_performance_optimizations.sil b/test/SILOptimizer/mandatory_performance_optimizations.sil
index 9298c1f2d45a2..2fc3d0d4334f3 100644
--- a/test/SILOptimizer/mandatory_performance_optimizations.sil
+++ b/test/SILOptimizer/mandatory_performance_optimizations.sil
@@ -1,6 +1,7 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -mandatory-performance-optimizations | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -mandatory-performance-optimizations -enable-experimental-feature Lifetimes | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
 
 sil_stage canonical
 
@@ -8,6 +9,10 @@ import Builtin
 import Swift
 import SwiftShims
 
+struct NonTrivialStruct {
+  var s: String
+}
+
 sil_global [let] @g1 : $Int32
 sil_global [let] @g2 : $Int32
 
@@ -202,8 +207,29 @@ bb3:
   return %1 : $Int32
 }
 
+sil @createNonTrivialStruct : $@convention(thin) (Int) -> @owned NonTrivialStruct
+
+// CHECK-LABEL: sil [no_allocation] [perf_constraint] [ossa] @test_dead_alloc_elimination_with_mark_dependence :
+// CHECK-NOT:     alloc_stack
+// CHECK:       } // end sil function 'test_dead_alloc_elimination_with_mark_dependence'
+sil [ossa] [no_allocation] @test_dead_alloc_elimination_with_mark_dependence : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = alloc_stack [lexical] $Int
+  store %0 to [trivial] %1
+  %4 = load [trivial] %1
+  %5 = function_ref @createNonTrivialStruct : $@convention(thin) (Int) -> @owned NonTrivialStruct
+  %6 = apply %5(%4) : $@convention(thin) (Int) -> @owned NonTrivialStruct
+  %7 = mark_dependence [nonescaping] %6 on %1
+  %9 = mark_dependence [nonescaping] %7 on %1
+  %10 = destructure_struct %9
+  destroy_value %10
+  %12 = tuple ()
+  dealloc_stack %1
+  return %12
+}
+
 // CHECK-LABEL: sil [no_locks] [perf_constraint] [ossa] @remove_metatype_arg :
-// CHECK:         [[F:%.*]] = function_ref @$s12metatype_argTf4dnn_n : $@convention(thin) (Int, @owned Builtin.NativeObject) -> @owned Builtin.NativeObject
+// CHECK:         [[F:%.*]] = function_ref @$s12metatype_argTf4ndn_n : $@convention(thin) (Int, @owned Builtin.NativeObject) -> @owned Builtin.NativeObject
 // CHECK:         [[A:%.*]] = apply [[F]](%0, %1) : $@convention(thin) (Int, @owned Builtin.NativeObject) -> @owned Builtin.NativeObject
 // CHECK:         return [[A]]
 // CHECK:       } // end sil function 'remove_metatype_arg'
@@ -222,8 +248,80 @@ bb0(%0 : $Int, %1 : $@thick Int.Type, %2 : @owned $Builtin.NativeObject):
   return %2 : $Builtin.NativeObject
 }
 
+sil [no_locks] [perf_constraint] [ossa] @dont_remove_metatype_arg_lifetime : $@convention(thin) (Int, UnsafeRawPointer) -> @lifetime(borrow 1) Span<Int> {
+bb0(%0 : $Int, %1 : $UnsafeRawPointer):
+  %3 = metatype $@thick Int.Type
+  %7 = function_ref @metatype_arg_lifetime : $@convention(thin) (Int, @thick Int.Type, UnsafeRawPointer) -> @lifetime(borrow 2) Span<Int>
+  %8 = apply %7(%0, %3, %1) : $@convention(thin) (Int, @thick Int.Type, UnsafeRawPointer) -> @lifetime(borrow 2) Span<Int>
+  return %8
+}
+
+sil [ossa] @get_span : $@convention(thin) (UnsafeRawPointer) -> @lifetime(borrow 0) Span<Int>
+
+// CHECK-NOT: sil [signature_optimized_thunk] [ossa] @metatype_arg_lifetime :
+sil [ossa] @metatype_arg_lifetime : $@convention(thin) (Int, @thick Int.Type, UnsafeRawPointer) -> @lifetime(borrow 2) Span<Int> {
+bb0(%0 : $Int, %1 : $@thick Int.Type, %2 : $UnsafeRawPointer):
+  fix_lifetime %1 : $@thick Int.Type
+  %3 = function_ref @get_span : $@convention(thin) (UnsafeRawPointer) -> @lifetime(borrow 0) Span<Int>
+  %4 = apply %3(%2) : $@convention(thin) (UnsafeRawPointer) -> @lifetime(borrow 0) Span<Int>
+  return %4
+}
+
+sil [no_locks] [perf_constraint] [ossa] @can_remove_metatype_arg_lifetime : $@convention(thin) (Int, UnsafeRawPointer) -> @lifetime(borrow 1) Span<Int> {
+bb0(%0 : $Int, %1 : $UnsafeRawPointer):
+  %3 = metatype $@thick Int.Type
+  %7 = function_ref @metatype_arg_lifetime_opt : $@convention(thin) (UnsafeRawPointer, Int, @thick Int.Type) -> @lifetime(borrow 0) Span<Int>
+  %8 = apply %7(%1, %0, %3) : $@convention(thin) (UnsafeRawPointer, Int, @thick Int.Type) -> @lifetime(borrow 0) Span<Int>
+  return %8
+}
+
+// CHECK: sil [signature_optimized_thunk] [ossa] @metatype_arg_lifetime_opt :
+sil [ossa] @metatype_arg_lifetime_opt : $@convention(thin) (UnsafeRawPointer, Int, @thick Int.Type) -> @lifetime(borrow 0) Span<Int> {
+bb0(%2 : $UnsafeRawPointer, %0 : $Int, %1 : $@thick Int.Type):
+  fix_lifetime %1 : $@thick Int.Type
+  %3 = function_ref @get_span : $@convention(thin) (UnsafeRawPointer) -> @lifetime(borrow 0) Span<Int>
+  %4 = apply %3(%2) : $@convention(thin) (UnsafeRawPointer) -> @lifetime(borrow 0) Span<Int>
+  return %4
+}
+
+sil [no_locks] [perf_constraint] [ossa] @dont_remove_metatype_arg_lifetime_inout : $@convention(thin) (Int, @lifetime(copy 2) @inout MutableSpan<Int>, @owned MutableSpan<Int>) -> () {
+bb0(%0 : $Int, %1 : $*MutableSpan<Int>, %2 : @owned $MutableSpan<Int>):
+  %3 = metatype $@thick Int.Type
+  %7 = function_ref @metatype_arg_lifetime_inout : $@convention(thin) (Int, @thick Int.Type, @lifetime(copy 3) @inout MutableSpan<Int>, @owned MutableSpan<Int>) -> ()
+  %8 = apply %7(%0, %3, %1, %2) : $@convention(thin) (Int, @thick Int.Type, @lifetime(copy 3) @inout MutableSpan<Int>, @owned MutableSpan<Int>) -> ()
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-NOT: sil [signature_optimized_thunk] [ossa] @metatype_arg_lifetime_inout :
+sil [ossa] @metatype_arg_lifetime_inout : $@convention(thin) (Int, @thick Int.Type, @lifetime(copy 3) @inout MutableSpan<Int>, @owned MutableSpan<Int>) -> () {
+bb0(%0 : $Int, %1 : $@thick Int.Type, %2 : $*MutableSpan<Int>, %3 : @owned $MutableSpan<Int>):
+  fix_lifetime %1 : $@thick Int.Type
+  destroy_value %3
+  %r = tuple ()
+  return %r
+}
+
+sil [no_locks] [perf_constraint] [ossa] @dont_remove_metatype_arg_lifetime_inout_source : $@convention(thin) (Int, @lifetime(copy 2) @inout MutableSpan<Int>, @owned MutableSpan<Int>) -> () {
+bb0(%0 : $Int, %1 : $*MutableSpan<Int>, %2 : @owned $MutableSpan<Int>):
+  %3 = metatype $@thick Int.Type
+  %7 = function_ref @metatype_arg_lifetime_inout_source : $@convention(thin) (@lifetime(copy 3) @inout MutableSpan<Int>, Int, @thick Int.Type, @owned MutableSpan<Int>) -> ()
+  %8 = apply %7(%1, %0, %3, %2) : $@convention(thin) (@lifetime(copy 3) @inout MutableSpan<Int>, Int, @thick Int.Type, @owned MutableSpan<Int>) -> ()
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-NOT: sil [signature_optimized_thunk] [ossa] @metatype_arg_lifetime_inout_source :
+sil [ossa] @metatype_arg_lifetime_inout_source : $@convention(thin) (@lifetime(copy 3) @inout MutableSpan<Int>, Int, @thick Int.Type, @owned MutableSpan<Int>) -> () {
+bb0(%2 : $*MutableSpan<Int>, %0 : $Int, %1 : $@thick Int.Type, %3 : @owned $MutableSpan<Int>):
+  fix_lifetime %1 : $@thick Int.Type
+  destroy_value %3
+  %r = tuple ()
+  return %r
+}
+
 // CHECK-LABEL: sil [no_locks] [perf_constraint] [ossa] @remove_metatype_arg_throws :
-// CHECK:         [[F:%.*]] = function_ref @$s19metatype_arg_throwsTf4dnn_n : $@convention(thin) (Int, @owned Builtin.NativeObject) -> (@owned Builtin.NativeObject, @error any Error)
+// CHECK:         [[F:%.*]] = function_ref @$s19metatype_arg_throwsTf4ndn_n : $@convention(thin) (Int, @owned Builtin.NativeObject) -> (@owned Builtin.NativeObject, @error any Error)
 // CHECK:         try_apply [[F]](%0, %1) : $@convention(thin) (Int, @owned Builtin.NativeObject) -> (@owned Builtin.NativeObject, @error any Error), normal bb1, error bb2
 // CHECK:       bb1([[R:%.*]] : @owned $Builtin.NativeObject):
 // CHECK:         return [[R]]
@@ -250,16 +348,17 @@ bb0(%0 : $Int, %1 : $@thick Int.Type, %2 : @owned $Builtin.NativeObject):
   return %2 : $Builtin.NativeObject
 }
 
-// CHECK-LABEL: sil [perf_constraint] [ossa] @$s12metatype_argTf4dnn_n : $@convention(thin) (Int, @owned Builtin.NativeObject) -> @owned Builtin.NativeObject {
+// CHECK-LABEL: sil [perf_constraint] [ossa] @$s19metatype_arg_throwsTf4ndn_n : $@convention(thin) (Int, @owned Builtin.NativeObject) -> (@owned Builtin.NativeObject, @error any Error) {
 // CHECK:       bb0(%0 : $Int, %1 : @owned $Builtin.NativeObject):
 // CHECK:         %2 = metatype $@thick Int.Type
 // CHECK:         fix_lifetime %2 : $@thick Int.Type
 // CHECK:         return %1 : $Builtin.NativeObject
-// CHECK:       } // end sil function '$s12metatype_argTf4dnn_n'
+// CHECK:       } // end sil function '$s19metatype_arg_throwsTf4ndn_n'
 
-// CHECK-LABEL: sil [perf_constraint] [ossa] @$s19metatype_arg_throwsTf4dnn_n : $@convention(thin) (Int, @owned Builtin.NativeObject) -> (@owned Builtin.NativeObject, @error any Error) {
+// CHECK-LABEL: sil [perf_constraint] [ossa] @$s12metatype_argTf4ndn_n : $@convention(thin) (Int, @owned Builtin.NativeObject) -> @owned Builtin.NativeObject {
 // CHECK:       bb0(%0 : $Int, %1 : @owned $Builtin.NativeObject):
 // CHECK:         %2 = metatype $@thick Int.Type
 // CHECK:         fix_lifetime %2 : $@thick Int.Type
 // CHECK:         return %1 : $Builtin.NativeObject
-// CHECK:       } // end sil function '$s19metatype_arg_throwsTf4dnn_n'
+// CHECK:       } // end sil function '$s12metatype_argTf4ndn_n'
+
diff --git a/test/SILOptimizer/mem-behavior-cache-bug.sil b/test/SILOptimizer/mem-behavior-cache-bug.sil
index caeff7e6e62a2..a532709834568 100644
--- a/test/SILOptimizer/mem-behavior-cache-bug.sil
+++ b/test/SILOptimizer/mem-behavior-cache-bug.sil
@@ -1,4 +1,4 @@
-// RUN: %sil-opt -temp-rvalue-opt %s -o /dev/null 
+// RUN: %sil-opt -temp-rvalue-elimination %s -o /dev/null 
 
 // This test exposes a bug in the MemBehavior cache invalidation mechanism.
 // With this bug, the optimizer aborts with a SIL memory lifetime failure
diff --git a/test/SILOptimizer/mem-behavior.sil b/test/SILOptimizer/mem-behavior.sil
index 1108217514454..82c5c92f1c31b 100644
--- a/test/SILOptimizer/mem-behavior.sil
+++ b/test/SILOptimizer/mem-behavior.sil
@@ -1250,11 +1250,16 @@ bb0(%0 : $Builtin.RawPointer):
 // CHECK-NEXT:      debug_value %0 : $*Int, let, name "x"
 // CHECK-NEXT:      %1 = alloc_stack $Int
 // CHECK-NEXT:    r=0,w=0
+// CHECK:       PAIR #2.
+// CHECK-NEXT:      debug_value undef : $*Int, let, name "y"
+// CHECK-NEXT:      %0 = alloc_stack $Int
+// CHECK-NEXT:    r=0,w=0
 sil @test_debug_value : $@convention(thin) () -> () {
 bb0:
   %0 = alloc_stack $Int
   %1 = alloc_stack $Int
   debug_value %0 : $*Int, let, name "x"
+  debug_value undef : $*Int, let, name "y"
   dealloc_stack %1 : $*Int
   dealloc_stack %0 : $*Int
   %r = tuple ()
@@ -1435,6 +1440,34 @@ bb0:
   return %5 : $()
 }
 
+// CHECK-LABEL: @builtin_initializer_and_class
+// CHECK:       PAIR #0.
+// CHECK-NEXT:      %3 = builtin "zeroInitializer"(%2 : $*Int32) : $()
+// CHECK-NEXT:      %1 = ref_element_addr %0 : $C, #C.prop
+// CHECK-NEXT:    r=0,w=0
+// CHECK:       PAIR #1.
+// CHECK-NEXT:      %3 = builtin "zeroInitializer"(%2 : $*Int32) : $()
+// CHECK-NEXT:      %2 = alloc_stack $Int32
+// CHECK-NEXT:    r=0,w=1
+// CHECK:       PAIR #2.
+// CHECK-NEXT:      %4 = builtin "prepareInitialization"(%2 : $*Int32) : $()
+// CHECK-NEXT:      %1 = ref_element_addr %0 : $C, #C.prop
+// CHECK-NEXT:    r=0,w=0
+// CHECK:       PAIR #3.
+// CHECK-NEXT:      %4 = builtin "prepareInitialization"(%2 : $*Int32) : $()
+// CHECK-NEXT:      %2 = alloc_stack $Int32
+// CHECK-NEXT:    r=0,w=1
+sil @builtin_initializer_and_class : $@convention(thin) (@guaranteed C) -> () {
+bb0(%0 : $C):
+  %1 = ref_element_addr %0, #C.prop
+  %2 = alloc_stack $Int32
+  %3 = builtin "zeroInitializer"(%2 : $*Int32) : $()
+  %4 = builtin "prepareInitialization"(%2 : $*Int32) : $()
+  dealloc_stack %2
+  %6 = tuple ()
+  return %6
+}
+
 // CHECK-LABEL: @test_stored_pointer
 // CHECK:       PAIR #2.
 // CHECK-NEXT:      %5 = apply %4(%2) : $@convention(thin) (@in Builtin.RawPointer) -> ()
@@ -1925,7 +1958,7 @@ bb0(%0 : $*C, %1 : $*C, %2 : @owned $C):
 // CHECK:      PAIR #1.
 // CHECK-NEXT:   mark_dependence_addr %1 : $*C on %2 : $C
 // CHECK-NEXT:   %1 = argument of bb0 : $*C
-// CHECK-NEXT:   r=0,w=0
+// CHECK-NEXT:   r=1,w=1
 // CHECK:      PAIR #2.
 // CHECK-NEXT:     mark_dependence_addr %1 : $*C on %0 : $*C
 // CHECK-NEXT:   %0 = argument of bb0 : $*C
@@ -1933,11 +1966,27 @@ bb0(%0 : $*C, %1 : $*C, %2 : @owned $C):
 // CHECK:      PAIR #3.
 // CHECK-NEXT:    mark_dependence_addr %1 : $*C on %0 : $*C
 // CHECK-NEXT:  %1 = argument of bb0 : $*C
-// CHECK-NEXT:  r=0,w=0
-sil [ossa] @test_mark_dependence_addr : $@convention(thin) (@in_guaranteed C, @in_guaranteed C, @guaranteed C) -> () {
+// CHECK-NEXT:  r=1,w=1
+sil [ossa] @test_mark_dependence_addr : $@convention(thin) (@in_guaranteed C, @inout C, @guaranteed C) -> () {
 bb0(%0 : $*C, %1 : $*C, %2 : @guaranteed $C):
   mark_dependence_addr %1 on %2
   mark_dependence_addr %1 on %0
   %99 = tuple ()
   return %99 : $()
 }
+
+sil @returns_tuple : $@convention(thin) () -> (Int64, @out UInt64)
+
+// CHECK-LABEL: @aliasing_apply_with_direct_and_indirect_result
+// CHECK:       PAIR #0.
+// CHECK-NEXT:     %2 = apply %1(%0) : $@convention(thin) () -> (Int64, @out UInt64)
+// CHECK-NEXT:     %0 = argument of bb0 : $*UInt64
+// CHECK-NEXT:     r=0,w=1
+sil [ossa] @aliasing_apply_with_direct_and_indirect_result : $@convention(thin) () -> @out UInt64 {
+bb0(%0 : $*UInt64):
+  %1 = function_ref @returns_tuple : $@convention(thin) () -> (Int64, @out UInt64)
+  %2 = apply %1(%0) : $@convention(thin) () -> (Int64, @out UInt64)
+  %99 = tuple ()
+  return %99 : $()
+}
+
diff --git a/test/SILOptimizer/mem2reg.sil b/test/SILOptimizer/mem2reg.sil
index 79d8a41a13b67..4284c0cd608eb 100644
--- a/test/SILOptimizer/mem2reg.sil
+++ b/test/SILOptimizer/mem2reg.sil
@@ -29,6 +29,24 @@ struct Pair<T, U> {
   var u: U
 }
 
+class C {}
+
+struct J {
+  var c: C
+}
+
+struct I {
+  var j: J
+}
+
+struct S1 {
+  var i: I
+}
+
+struct S2 {
+  var t: (J, J)
+}
+
 ///////////
 // Tests //
 ///////////
@@ -578,3 +596,60 @@ bb0:
   dealloc_stack %11 : $*Pair<T, ()>
   return undef : $()
 }
+
+// CHECK-LABEL: sil @promo_proj_uac_1 : {{.*}} {
+// CHECK-NOT:     alloc_stack
+// CHECK-LABEL: } // end sil function 'promo_proj_uac_1'
+sil @promo_proj_uac_1 : $@convention(thin) () -> () {
+bb0:
+  %s = apply undef() : $@convention(thin) () -> (@owned S1)
+  %addr = alloc_stack $S1
+  store %s to %addr
+  %i_addr = unchecked_addr_cast %addr to $*I
+  %j_addr = struct_element_addr %i_addr, #I.j
+  %j = load %j_addr
+  retain_value %j
+  destroy_addr %addr
+  dealloc_stack %addr
+  apply undef(%j) : $@convention(thin) (@owned J) -> ()
+  %retval = tuple ()
+  return %retval
+}
+
+// CHECK-LABEL: sil @promo_proj_uac_2 : {{.*}} {
+// CHECK-NOT:     alloc_stack
+// CHECK-LABEL: } // end sil function 'promo_proj_uac_2'
+sil @promo_proj_uac_2 : $@convention(thin) () -> () {
+bb0:
+  %s = apply undef() : $@convention(thin) () -> (@owned S2)
+  %addr = alloc_stack $S2
+  store %s to %addr
+  %t_addr = unchecked_addr_cast %addr to $*(J, J)
+  %j_addr = tuple_element_addr %t_addr, 0
+  %j = load %j_addr
+  retain_value %j
+  destroy_addr %addr
+  dealloc_stack %addr
+  apply undef(%j) : $@convention(thin) (@owned J) -> ()
+  %retval = tuple ()
+  return %retval
+}
+
+// CHECK-LABEL: sil @promo_proj_uac_3 : {{.*}} {
+// CHECK-NOT:     alloc_stack
+// CHECK-LABEL: } // end sil function 'promo_proj_uac_3'
+sil @promo_proj_uac_3 : $@convention(thin) () -> () {
+bb0:
+  %s = apply undef() : $@convention(thin) () -> (@owned S1)
+  %addr = alloc_stack $S1
+  store %s to %addr
+  %i_addr = unchecked_addr_cast %addr to $*I
+  %j_addr = unchecked_addr_cast %i_addr to $*J
+  %j = load %j_addr
+  retain_value %j
+  destroy_addr %addr
+  dealloc_stack %addr
+  apply undef(%j) : $@convention(thin) (@owned J) -> ()
+  %retval = tuple ()
+  return %retval
+}
diff --git a/test/SILOptimizer/mem2reg_ossa.sil b/test/SILOptimizer/mem2reg_ossa.sil
index 9104ac4375493..c762d9334857f 100644
--- a/test/SILOptimizer/mem2reg_ossa.sil
+++ b/test/SILOptimizer/mem2reg_ossa.sil
@@ -46,6 +46,22 @@ struct S {
   var field: C
 }
 
+struct J {
+  var c: C
+}
+
+struct I {
+  var j: J
+}
+
+struct S1 {
+  var i: I
+}
+
+struct S2 {
+  var t: (J, J)
+}
+
 ///////////
 // Tests //
 ///////////
@@ -761,3 +777,57 @@ entry(%instance : @owned $C):
   %retval = tuple ()
   return %retval : $()
 }
+
+// CHECK-LABEL: sil [ossa] @no_promo_proj_uac_1 : {{.*}} {
+// CHECK:         alloc_stack
+// CHECK-LABEL: } // end sil function 'no_promo_proj_uac_1'
+sil [ossa] @no_promo_proj_uac_1 : $@convention(thin) () -> () {
+bb0:
+  %s = apply undef() : $@convention(thin) () -> (@owned S1)
+  %addr = alloc_stack $S1
+  store %s to [init] %addr
+  %i_addr = unchecked_addr_cast %addr to $*I
+  %j_addr = struct_element_addr %i_addr, #I.j
+  %j = load [copy] %j_addr
+  destroy_addr %addr
+  dealloc_stack %addr
+  apply undef(%j) : $@convention(thin) (@owned J) -> ()
+  %retval = tuple ()
+  return %retval
+}
+
+// CHECK-LABEL: sil [ossa] @no_promo_proj_uac_2 : {{.*}} {
+// CHECK:         alloc_stack
+// CHECK-LABEL: } // end sil function 'no_promo_proj_uac_2'
+sil [ossa] @no_promo_proj_uac_2 : $@convention(thin) () -> () {
+bb0:
+  %s = apply undef() : $@convention(thin) () -> (@owned S2)
+  %addr = alloc_stack $S2
+  store %s to [init] %addr
+  %t_addr = unchecked_addr_cast %addr to $*(J, J)
+  %j_addr = tuple_element_addr %t_addr, 0
+  %j = load [copy] %j_addr
+  destroy_addr %addr
+  dealloc_stack %addr
+  apply undef(%j) : $@convention(thin) (@owned J) -> ()
+  %retval = tuple ()
+  return %retval
+}
+
+// CHECK-LABEL: sil [ossa] @promo_uac_uac : {{.*}} {
+// CHECK-NOT:     alloc_stack
+// CHECK-LABEL: } // end sil function 'promo_uac_uac'
+sil [ossa] @promo_uac_uac : $@convention(thin) () -> () {
+bb0:
+  %s = apply undef() : $@convention(thin) () -> (@owned S1)
+  %addr = alloc_stack $S1
+  store %s to [init] %addr
+  %i_addr = unchecked_addr_cast %addr to $*I
+  %j_addr = unchecked_addr_cast %i_addr to $*J
+  %j = load [copy] %j_addr
+  destroy_addr %addr
+  dealloc_stack %addr
+  apply undef(%j) : $@convention(thin) (@owned J) -> ()
+  %retval = tuple ()
+  return %retval
+}
diff --git a/test/SILOptimizer/mem2reg_ossa_nontrivial.sil b/test/SILOptimizer/mem2reg_ossa_nontrivial.sil
index 112d1e77e6114..586ffb64c160c 100644
--- a/test/SILOptimizer/mem2reg_ossa_nontrivial.sil
+++ b/test/SILOptimizer/mem2reg_ossa_nontrivial.sil
@@ -58,6 +58,11 @@ enum KlassOptional {
   case none
 }
 
+enum Result<S, F> {
+  case success(S)
+  case failure(F)
+}
+
 sil [ossa] @get_nontrivialstruct : $@convention(thin) () -> @owned NonTrivialStruct
 sil [ossa] @get_nontrivialenum : $@convention(thin) () -> @owned NonTrivialEnum
 sil [ossa] @get_optionalnontrivialstruct : $@convention(thin) () -> @owned FakeOptional<NonTrivialStruct>
@@ -1549,3 +1554,160 @@ bb9:
   dealloc_stack %5
   br bb3
 }
+
+// CHECK-LABEL: sil [ossa] @test_end_lifetime_of_trivial_enum_case :
+// CHECK-NOT:     alloc_stack
+// CHECK:       bb2(%{{[0-9]+}} : $Int): 
+// CHECK:         fix_lifetime
+// CHECK:         end_borrow
+// CHECK:         end_lifetime %1
+// CHECK:       bb3:
+// CHECK-LABEL: } // end sil function 'test_end_lifetime_of_trivial_enum_case'
+sil [ossa] @test_end_lifetime_of_trivial_enum_case : $@convention(thin) (@inout X, @owned Result<X, Int>) -> () {
+bb0(%0 : $*X, %1 : @owned $Result<X, Int>):
+  %2 = alloc_stack $Result<X, Int>
+  store %1 to [init] %2
+  %3 = load_borrow %2
+  switch_enum %3, case #Result.success!enumelt: bb1, case #Result.failure!enumelt: bb2
+
+bb1(%10 : @guaranteed $X):
+  end_borrow %3
+  %12 = load [take] %2
+  %13 = unchecked_enum_data %12 : $Result<X, Int>, #Result.success!enumelt
+  store %13 to [assign] %0
+  br bb3
+
+bb2(%20 : $Int):
+  end_borrow %3
+  %22 = load_borrow %2
+  %23 = unchecked_enum_data %22, #Result.failure!enumelt
+  fix_lifetime %23
+  end_borrow %22
+  br bb3
+
+bb3:
+  dealloc_stack %2
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil [ossa] @end_lifetime_at_trivial_case_dealloc_stack : {{.*}} {
+// CHECK-NOT:     alloc_stack
+// CHECK:         [[IN:%[^,]+]] = load [copy]
+// CHECK:         [[IN_BORROW:%[^,]+]] = begin_borrow [[IN]]
+// CHECK:         switch_enum [[IN_BORROW]]
+// CHECK-SAME:        case #Result.success!enumelt: [[INT:bb[0-9]+]]
+// CHECK:       [[INT]]({{%[^,]+}} : $Int):
+// CHECK:         end_borrow [[IN_BORROW]]
+// CHECK:         end_lifetime [[IN]]
+// CHECK-LABEL: } // end sil function 'end_lifetime_at_trivial_case_dealloc_stack'
+sil [ossa] @end_lifetime_at_trivial_case_dealloc_stack : $@convention(thin) (@in_guaranteed Result<Int, X>) -> () {
+entry(%in_addr : $*Result<Int, X>):
+  %main_addr = alloc_stack $Result<Int, X>
+  %in = load [copy] %in_addr
+  store %in to [init] %main_addr
+  %in_borrow = load_borrow %main_addr
+  switch_enum %in_borrow,
+      case #Result.success!enumelt: int,
+      case #Result.failure!enumelt: full
+
+int(%6 : $Int):
+  end_borrow %in_borrow
+  %temp = alloc_stack $Result<Int, X>
+  %in_copy = load [copy] %main_addr
+  store %in_copy to [init] %temp
+  br int2
+
+int2:
+  dealloc_stack %temp
+  br exit
+
+full(%13 : @guaranteed $X):
+  end_borrow %in_borrow
+  br exit
+
+exit:
+  destroy_addr %main_addr
+  dealloc_stack %main_addr
+  %18 = tuple ()
+  return %18
+}
+
+// CHECK-LABEL: sil [ossa] @end_lifetime_at_trivial_case_dealloc_stack_2 : {{.*}} {
+// CHECK:       bb0([[IN_ADDR:%[^,]+]] :
+// CHECK:         [[IN_COPY:%[^,]+]] = load [copy] [[IN_ADDR]]
+// CHECK:         [[IN_BORROW:%[^,]+]] = begin_borrow [[IN_COPY]]
+// CHECK:         switch_enum [[IN_BORROW]]
+// CHECK:             case #Result.success!enumelt: [[INT:bb[0-9]+]]
+// CHECK:       [[INT]]
+// CHECK:         end_borrow [[IN_BORROW]]
+// CHECK:         end_lifetime [[IN_COPY]]
+// CHECK-LABEL: } // end sil function 'end_lifetime_at_trivial_case_dealloc_stack_2'
+sil [ossa] @end_lifetime_at_trivial_case_dealloc_stack_2 : $@convention(thin) (@in_guaranteed Result<Int, X>) -> () {
+entry(%in_addr : $*Result<Int, X>):
+  %main_addr = alloc_stack $Result<Int, X>
+  %temp = alloc_stack $Result<Int, X>
+  %in = load [copy] %in_addr
+  store %in to [init] %main_addr
+  %in_borrow = load_borrow %main_addr
+  switch_enum %in_borrow,
+      case #Result.success!enumelt: int,
+      case #Result.failure!enumelt: x
+
+int(%int : $Int):
+  end_borrow %in_borrow
+  %in_copy = load [copy] %main_addr
+  store %in_copy to [init] %temp
+  br int2
+
+int2:
+  br exit
+
+x(%13 : @guaranteed $X):
+  end_borrow %in_borrow
+  br exit
+
+exit:
+  destroy_addr %main_addr
+  dealloc_stack %temp
+  dealloc_stack %main_addr
+  %retval = tuple ()
+  return %retval
+}
+
+// CHECK-LABEL: sil [ossa] @end_lifetime_at_trivial_case_dealloc_stack_3 : {{.*}} {
+// CHECK:       bb0([[IN_ADDR:%[^,]+]] :
+// CHECK:         [[IN_BORROW:%[^,]+]] = load_borrow [[IN_ADDR]]
+// CHECK:         switch_enum [[IN_BORROW]]
+// CHECK:             case #Result.success!enumelt: [[INT:bb[0-9]+]]
+// CHECK:       [[INT]]
+// CHECK:         end_borrow [[IN_BORROW]]
+// CHECK:         [[IN_COPY:%[^,]+]] = load [copy] [[IN_ADDR]]
+// CHECK:         end_lifetime [[IN_COPY]]
+// CHECK-LABEL: } // end sil function 'end_lifetime_at_trivial_case_dealloc_stack_3'
+sil [ossa] @end_lifetime_at_trivial_case_dealloc_stack_3 : $@convention(thin) (@in_guaranteed Result<Int, X>) -> () {
+entry(%in_addr : $*Result<Int, X>):
+  %in_borrow = load_borrow %in_addr
+  switch_enum %in_borrow,
+      case #Result.success!enumelt: int,
+      case #Result.failure!enumelt: x
+
+int(%int : $Int):
+  end_borrow %in_borrow
+  %temp = alloc_stack $Result<Int, X>
+  %in_copy = load [copy] %in_addr
+  store %in_copy to [init] %temp
+  dealloc_stack %temp
+  br int2
+
+int2:
+  br exit
+
+x(%13 : @guaranteed $X):
+  end_borrow %in_borrow
+  br exit
+
+exit:
+  %retval = tuple ()
+  return %retval
+}
diff --git a/test/SILOptimizer/moveonly_addresschecker.swift b/test/SILOptimizer/moveonly_addresschecker.swift
index f3331c0f84da9..4543a24ab9eae 100644
--- a/test/SILOptimizer/moveonly_addresschecker.swift
+++ b/test/SILOptimizer/moveonly_addresschecker.swift
@@ -1,23 +1,28 @@
 // RUN: %target-swift-emit-sil -sil-verify-all -verify \
 // RUN: -enable-experimental-feature NoImplicitCopy \
 // RUN: -enable-experimental-feature MoveOnlyClasses \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
+// RUN: -enable-experimental-feature BuiltinModule \
 // RUN: -Xllvm -sil-print-final-ossa-module %s | %FileCheck %s
 
 // RUN: %target-swift-emit-sil -O -sil-verify-all -verify \
 // RUN: -enable-experimental-feature NoImplicitCopy \
 // RUN: -enable-experimental-feature MoveOnlyClasses \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
+// RUN: -enable-experimental-feature BuiltinModule \
 // RUN: %s
 
 // REQUIRES: swift_feature_MoveOnlyClasses
 // REQUIRES: swift_feature_NoImplicitCopy
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_BuiltinModule
 
 // This file contains tests that used to crash due to verifier errors. It must
 // be separate from moveonly_addresschecker_diagnostics since when we fail on
 // the diagnostics in that file, we do not actually run the verifier.
 
+import Builtin
+
 struct TestTrivialReturnValue : ~Copyable {
     var i: Int = 5
 
@@ -64,15 +69,22 @@ struct TestCoroAccessorOfCoroAccessor<T : ~Escapable> : ~Copyable & ~Escapable {
   var t: T
 
   var inner: TestCoroAccessorOfCoroAccessor<T> {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       fatalError()
     }
   }
   var outer: TestCoroAccessorOfCoroAccessor<T> {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield inner
     }
   }
 }
+
+@usableFromInline
+internal func unsafeBitCast<T: ~Escapable & ~Copyable, U>(
+   _ x: consuming T, to type: U.Type
+) -> U {
+   Builtin.reinterpretCast(x)
+}
diff --git a/test/SILOptimizer/moveonly_addresschecker_diagnostics_partial_consume_ufi.swift b/test/SILOptimizer/moveonly_addresschecker_diagnostics_partial_consume_ufi.swift
index 6ea9a06008120..81c4e7c853b7a 100644
--- a/test/SILOptimizer/moveonly_addresschecker_diagnostics_partial_consume_ufi.swift
+++ b/test/SILOptimizer/moveonly_addresschecker_diagnostics_partial_consume_ufi.swift
@@ -34,10 +34,10 @@ internal struct Agg_Internal_UFI : ~Copyable {
 
 @_alwaysEmitIntoClient
 func piecewise_Agg_Internal_UFI(_ a: consuming Agg_Internal_UFI) {
-  take(a.u1) // expected-fragile-error{{cannot partially consume 'a' of non-frozen usableFromInline type 'Agg_Internal_UFI' within a function annotated @_alwaysEmitIntoClient}}
+  take(a.u1) // expected-fragile-error{{cannot partially consume 'a' of non-frozen usableFromInline type 'Agg_Internal_UFI' within a function annotated '@_alwaysEmitIntoClient'}}
              // expected-resilient-error@-1{{field 'a.u1' was consumed but not reinitialized; the field must be reinitialized during the access}}
              // expected-resilient-note@-2{{consumed here}}
-  take(a.u2) // expected-fragile-error{{cannot partially consume 'a' of non-frozen usableFromInline type 'Agg_Internal_UFI' within a function annotated @_alwaysEmitIntoClient}}
+  take(a.u2) // expected-fragile-error{{cannot partially consume 'a' of non-frozen usableFromInline type 'Agg_Internal_UFI' within a function annotated '@_alwaysEmitIntoClient'}}
              // expected-resilient-error@-1{{field 'a.u2' was consumed but not reinitialized; the field must be reinitialized during the access}}
              // expected-resilient-note@-2{{consumed here}}
 }
diff --git a/test/SILOptimizer/moveonly_addressors.swift b/test/SILOptimizer/moveonly_addressors.swift
index 561732f8775da..12ae19ce92272 100644
--- a/test/SILOptimizer/moveonly_addressors.swift
+++ b/test/SILOptimizer/moveonly_addressors.swift
@@ -1,9 +1,10 @@
-// RUN: %target-swift-frontend  -enable-experimental-feature BuiltinModule -parse-stdlib -module-name Swift -DADDRESS_ONLY -emit-sil -verify %s
-// RUN: %target-swift-frontend  -enable-experimental-feature BuiltinModule -parse-stdlib -module-name Swift -DLOADABLE -emit-sil -verify %s
-// RUN: %target-swift-frontend  -enable-experimental-feature BuiltinModule -parse-stdlib -module-name Swift -DTRIVIAL -emit-sil -verify %s
-// RUN: %target-swift-frontend  -enable-experimental-feature BuiltinModule -parse-stdlib -module-name Swift -DEMPTY -emit-sil -verify %s
+// RUN: %target-swift-frontend  -enable-experimental-feature BuiltinModule -enable-experimental-feature AddressableParameters -parse-stdlib -module-name Swift -DADDRESS_ONLY -emit-sil -verify %s
+// RUN: %target-swift-frontend  -enable-experimental-feature BuiltinModule -enable-experimental-feature AddressableParameters -parse-stdlib -module-name Swift -DLOADABLE -emit-sil -verify %s
+// RUN: %target-swift-frontend  -enable-experimental-feature BuiltinModule -enable-experimental-feature AddressableParameters -parse-stdlib -module-name Swift -DTRIVIAL -emit-sil -verify %s
+// RUN: %target-swift-frontend  -enable-experimental-feature BuiltinModule -enable-experimental-feature AddressableParameters -parse-stdlib -module-name Swift -DEMPTY -emit-sil -verify %s
 
 // REQUIRES: swift_feature_BuiltinModule
+// REQUIRES: swift_feature_AddressableParameters
 
 // TODO: Use the real stdlib types once `UnsafePointer` supports noncopyable
 // types.
@@ -54,6 +55,13 @@ struct S {
     unsafeAddress { return makeUpAPointer() }
     unsafeMutableAddress { return makeUpAPointer() }
   }
+
+  var pointer: Builtin.RawPointer {
+    @_addressableSelf
+    get {
+      Builtin.addressOfBorrow(self)
+    }
+  }
 }
 
 struct SNC: ~Copyable {
@@ -122,3 +130,10 @@ func test(mut_snc snc: inout SNC) {
   mod(&snc.mutableData)
   take(snc.mutableData) // expected-error{{missing reinitialization of inout parameter 'snc.mutableData' after consume}} expected-note{{consumed here}}
 }
+
+// Test calling passing a no-implicit-copy value as an indirect funtion argument. This requires the
+// MoveOnlyWrappedTypeEliminator to handle a store_borrow with multiple move-only operands without crashing in the
+// verifier with invalid operand ownership.
+func testAddressableNoImplicitCopy(s: consuming S) -> Builtin.RawPointer {
+  s.pointer
+}
diff --git a/test/SILOptimizer/moveonly_borrow_accessors.swift b/test/SILOptimizer/moveonly_borrow_accessors.swift
new file mode 100644
index 0000000000000..77cdd7e1c5eb8
--- /dev/null
+++ b/test/SILOptimizer/moveonly_borrow_accessors.swift
@@ -0,0 +1,144 @@
+// RUN: %target-swift-frontend -sil-verify-all -verify -emit-sil  -enable-experimental-feature BorrowAndMutateAccessors %s
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+
+public struct NC : ~Copyable {}
+
+func use<T : ~Copyable>(_ t: borrowing T) {}
+func consume<T : ~Copyable>(_ t: consuming T) {}
+
+public struct GenSimpleNCWrapper<T : ~Copyable> : ~Copyable {
+  var _prop: T
+
+  var prop: T {
+    borrow {
+      return _prop
+    }
+  }
+}
+
+public struct GenNCWrapper<T : ~Copyable> : ~Copyable {
+  var _prop: T
+  var _w: GenSimpleNCWrapper<T>
+
+  public var prop: T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var nested1: T {
+    borrow {
+      return _w.prop
+    }
+  }
+
+  var nested2: T {
+    borrow {
+      return prop
+    }
+  }
+
+  subscript(index: Int) -> T {
+    borrow {
+      return _prop
+    }
+  }
+
+  var nested_subscript: T {
+    borrow {
+      return self[0]
+    }
+  }
+
+  var literal: Int {
+    borrow {
+      return 0
+    }
+  }
+}
+
+public struct SimpleNCWrapper: ~Copyable {
+  var _nc: NC
+
+  var nc: NC {
+    borrow {
+      return _nc
+    }
+  }
+}
+
+public struct NCWrapper: ~Copyable {
+  var _nc: NC
+  var _s: SimpleNCWrapper
+
+  var nc: NC {
+    borrow {
+      return _nc
+    }
+  }
+
+  var nested1: NC {
+    borrow {
+      return _s.nc
+    }
+  }
+
+  var nested2: NC {
+    borrow {
+      return nc
+    }
+  }
+
+  subscript(index: Int) -> NC {
+    borrow {
+      return _nc
+    }
+  }
+
+  var nested_subscript: NC {
+    borrow {
+      return self[0]
+    }
+  }
+
+  var literal: Int {
+    borrow {
+      return 0
+    }
+  }
+}
+
+func nctest() {
+  let w1 = GenNCWrapper(_prop: NC(), _w: GenSimpleNCWrapper(_prop: NC()))
+  use(w1.prop)
+  use(w1.nested1)
+  use(w1.nested2)
+  use(w1._w.prop)
+  consume(w1.prop) //expected-error{{'w1.prop' is borrowed and cannot be consumed}} expected-note{{consumed here}}
+
+  let w2 = GenNCWrapper(_prop: NC(), _w: GenSimpleNCWrapper(_prop: NC()))
+  var k1 = w2.prop //expected-error{{'w2.prop' is borrowed and cannot be consumed}} expected-note{{consumed here}}
+
+  use(k1)
+  k1 = NC()
+  use(k1)
+
+  let w3 = GenNCWrapper(_prop: NC(), _w: GenSimpleNCWrapper(_prop: NC())) //expected-error{{'w3' used after consume}}
+  consume(w3) // expected-note{{consumed here}}
+  use(w3.prop) // expected-note{{used here}}
+
+  let w4 = NCWrapper(_nc: NC(), _s: SimpleNCWrapper(_nc: NC()))
+  use(w4.nc)
+  use(w4.nested1)
+  use(w4.nested2)
+  use(w4._s.nc)
+  consume(w4.nc) // expected-error{{'w4.nc' is borrowed and cannot be consumed}} expected-note{{consumed here}}
+
+
+  let w5 = NCWrapper(_nc: NC(), _s: SimpleNCWrapper(_nc: NC()))
+  var k2 = w5.nc // expected-error{{'w5.nc' is borrowed and cannot be consumed}} expected-note{{consumed here}}
+  use(k2)
+  k2 = NC()
+  use(k2)
+}
diff --git a/test/SILOptimizer/moveonly_builtins.swift b/test/SILOptimizer/moveonly_builtins.swift
index 12bdd86bcfe7f..5ba65aada7e07 100644
--- a/test/SILOptimizer/moveonly_builtins.swift
+++ b/test/SILOptimizer/moveonly_builtins.swift
@@ -1,8 +1,8 @@
-// RUN: %target-swift-frontend-typecheck -verify %s -DILLEGAL \
+// RUN: %target-swift-frontend-typecheck -verify -verify-ignore-unrelated %s -DILLEGAL \
 // RUN:   -enable-builtin-module \
 // RUN:   -verify-additional-prefix illegal-
 
-// RUN: %target-swift-frontend -emit-sil -sil-verify-all -verify %s \
+// RUN: %target-swift-frontend -emit-sil -sil-verify-all -verify -verify-ignore-unrelated %s \
 // RUN:   -enable-builtin-module
 
 import Builtin
diff --git a/test/SILOptimizer/moveonly_checker_addressonly_fail.swift b/test/SILOptimizer/moveonly_checker_addressonly_fail.swift
index f9f32a278debd..4fb68356ce273 100644
--- a/test/SILOptimizer/moveonly_checker_addressonly_fail.swift
+++ b/test/SILOptimizer/moveonly_checker_addressonly_fail.swift
@@ -8,7 +8,7 @@ struct GenericAggregate<T> {
 }
 
 func test1<T>(_ x: T) {
-    @_noImplicitCopy let x2 = x // expected-error {{@_noImplicitCopy can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
+    @_noImplicitCopy let x2 = x // expected-error {{'@_noImplicitCopy' can not be used on a generic or existential typed binding or a nominal type containing such typed things}}
 
     // These fail b/c we use an unchecked_addr_cast to convert addresses from
     // @moveOnly to non-@moveOnly. We should change moveonly_to_copyable to
diff --git a/test/SILOptimizer/moveonly_objectchecker.sil b/test/SILOptimizer/moveonly_objectchecker.sil
index ffd53ae36da11..720be5a0f2db5 100644
--- a/test/SILOptimizer/moveonly_objectchecker.sil
+++ b/test/SILOptimizer/moveonly_objectchecker.sil
@@ -1,6 +1,7 @@
-// RUN: %target-sil-opt -sil-move-only-object-checker -enable-experimental-feature MoveOnlyClasses -enable-sil-verify-all -move-only-diagnostics-silently-emit-diagnostics %s | %FileCheck %s
+// RUN: %target-sil-opt -sil-move-only-object-checker -enable-experimental-feature MoveOnlyClasses -enable-experimental-feature Lifetimes -enable-sil-verify-all -move-only-diagnostics-silently-emit-diagnostics %s | %FileCheck %s
 
 // REQUIRES: swift_feature_MoveOnlyClasses
+// REQUIRES: swift_feature_Lifetimes
 
 sil_stage raw
 
@@ -8,14 +9,26 @@ import Swift
 
 class Klass: ~Copyable {}
 
+struct NCNE : ~Copyable, ~Escapable {}
+
+struct NCNEHolder : ~Copyable, ~Escapable {
+  var ncne: NCNE {
+    @_lifetime(borrow self)
+    get
+  }
+}
+
 sil @classUseMoveOnlyWithoutEscaping : $@convention(thin) (@guaranteed Klass) -> ()
 
+sil @read_ncne : $@yield_once @convention(method) (@guaranteed NCNEHolder) -> @lifetime(borrow 0) @yields @guaranteed NCNE
+sil @use_ncne : $@convention(thin) (@guaranteed NCNE) -> ()
+
 // CHECK-LABEL: sil [ossa] @chainErrorTest : $@convention(thin) (@guaranteed Klass) -> () {
 // CHECK-NOT: copy_value
 // CHECK: explicit_copy_value
 // CHECK-NOT: copy_value
 // CHECK: explicit_copy_value
-// CHECK-NOT: copy_value
+// CHECK-NOT: copy_valuea
 // CHECK: } // end sil function 'chainErrorTest'
 sil [ossa] @chainErrorTest : $@convention(thin) (@guaranteed Klass) -> () {
 bb0(%0 : @guaranteed $Klass):
@@ -51,3 +64,27 @@ bb0(%0 : @guaranteed $Klass):
   %30 = tuple ()
   return %30 : $()
 }
+
+// CHECK-LABEL: sil [ossa] @testCopyOfMarkDep : $@convention(thin) (@guaranteed NCNEHolder) -> () {
+// CHECK-NOT: explicit_copy_value
+// CHECK-NOT: copy_value
+// CHECK-LABEL: } // end sil function 'testCopyOfMarkDep'
+sil [ossa] @testCopyOfMarkDep : $@convention(thin) (@guaranteed NCNEHolder) -> () {
+bb0(%0 : @guaranteed $NCNEHolder):
+  %1 = copy_value %0
+  %2 = mark_unresolved_non_copyable_value [no_consume_or_assign] %1
+  debug_value %2, let, name "h", argno 1
+  %4 = function_ref @read_ncne : $@yield_once @convention(method) (@guaranteed NCNEHolder) -> @lifetime(borrow 0) @yields @guaranteed NCNE
+  (%5, %6) = begin_apply %4(%2) : $@yield_once @convention(method) (@guaranteed NCNEHolder) -> @lifetime(borrow 0) @yields @guaranteed NCNE
+  %7 = mark_dependence [unresolved] %5 on %6
+  %8 = mark_dependence [unresolved] %7 on %2
+  %9 = copy_value %8
+  %10 = mark_unresolved_non_copyable_value [no_consume_or_assign] %9
+  %11 = function_ref @use_ncne : $@convention(thin) (@guaranteed NCNE) -> ()
+  %12 = apply %11(%10) : $@convention(thin) (@guaranteed NCNE) -> ()
+  destroy_value %10
+  %14 = end_apply %6 as $()
+  destroy_value %2
+  %16 = tuple ()
+  return %16
+}
diff --git a/test/SILOptimizer/moveonly_raw_layout.swift b/test/SILOptimizer/moveonly_raw_layout.swift
index 38cfcf5b70582..084971b7d9b22 100644
--- a/test/SILOptimizer/moveonly_raw_layout.swift
+++ b/test/SILOptimizer/moveonly_raw_layout.swift
@@ -20,7 +20,7 @@ struct Lock: ~Copyable {
     // CHECK-NEXT: sil{{.*}} @[[INIT:\$.*4LockV.*fC]] :
     init() {
         // CHECK-NOT: destroy_addr
-        // CHECK: builtin "zeroInitializer"({{%.*}} : $*Lock)
+        // CHECK: builtin "prepareInitialization"({{%.*}} : $*Lock)
         // CHECK-NOT: destroy_addr
         // CHECK: [[F:%.*]] = function_ref @init_lock
         // CHECK: apply [[F]](
diff --git a/test/SILOptimizer/moveonly_read_coroutine.swift b/test/SILOptimizer/moveonly_read_coroutine.swift
index 15d044352864f..5e4a445e07b52 100644
--- a/test/SILOptimizer/moveonly_read_coroutine.swift
+++ b/test/SILOptimizer/moveonly_read_coroutine.swift
@@ -6,6 +6,16 @@
 class X {}
 
 struct NC: ~Copyable {
+  var field: Int = 0
+  var consumingGetter: Int {
+    consuming get { return 0 }
+  }
+  var readCoroutine: Int {
+    _read { yield field }
+  }
+  consuming func consumingFunc() -> Int { return 0 }
+  borrowing func borrowingFunc() -> Int { return 0 }
+
 #if EMPTY
 #elseif TRIVIAL
   var x: Int = 0
@@ -23,6 +33,10 @@ struct S {
   var data: NC {
     _read { yield NC() }
   }
+
+  subscript(index: Int) -> NC {
+    _read { yield NC() }
+  }
 }
 
 struct SNC: ~Copyable {
@@ -31,6 +45,10 @@ struct SNC: ~Copyable {
   var data: NC {
     _read { yield _data }
   }
+
+  subscript(index: Int) -> NC {
+    _read { yield _data }
+  }
 }
 
 class C {
@@ -39,35 +57,84 @@ class C {
   var data: NC {
     _read { yield _data }
   }
+
+  subscript(index: Int) -> NC {
+    _read { yield _data }
+  }
 }
 
 protocol P {
   @_borrowed
   var data: NC { get }
+
+  @_borrowed
+  subscript(index: Int) -> NC { get }
 }
 
 func borrow(_ nc: borrowing NC) {}
 func take(_ nc: consuming NC) {}
 
+func assume(_ b: Bool) { precondition(b, "uh oh") }
+
 func test(c: C) {
   borrow(c.data)
   take(c.data) // expected-error{{'c.data' is borrowed and cannot be consumed}} expected-note{{consumed here}}
+
+  borrow(c[0])
+  assume(c[0].field == 0)
+  assume(c[0].borrowingFunc() == 0)
+  assume(c[0].readCoroutine == 0)
+  // take(c[0]) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
+  assume(c[0].consumingGetter == 0) // expected-error {{'c.subscript' is borrowed and cannot be consumed}} expected-note {{consumed here}}
+  // assume(c[0].consumingFunc() == 0) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
 }
 func test(s: S) {
   borrow(s.data)
   take(s.data) // expected-error{{'s.data' is borrowed and cannot be consumed}} expected-note{{consumed here}}
+
+  borrow(s[0])
+  assume(s[0].field == 0)
+  assume(s[0].borrowingFunc() == 0)
+  assume(s[0].readCoroutine == 0)
+  // take(s[0]) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
+  assume(s[0].consumingGetter == 0) // expected-error {{'s.subscript' is borrowed and cannot be consumed}} expected-note {{consumed here}}
+  // assume(s[0].consumingFunc() == 0) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
 }
 func test(snc: borrowing SNC) {
   borrow(snc.data)
   take(snc.data) // expected-error{{'snc.data' is borrowed and cannot be consumed}} expected-note{{consumed here}}
+
+  borrow(snc[0])
+  assume(snc[0].field == 0)
+  assume(snc[0].borrowingFunc() == 0)
+  assume(snc[0].readCoroutine == 0)
+  // take(snc[0]) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
+  assume(snc[0].consumingGetter == 0) // expected-error {{'snc.subscript' is borrowed and cannot be consumed}} expected-note {{consumed here}}
+  // assume(snc[0].consumingFunc() == 0) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
 }
 
 func test<T: P>(t: T) {
   borrow(t.data)
   take(t.data) // expected-error{{'t.data' is borrowed and cannot be consumed}} expected-note{{consumed here}}
+
+  borrow(t[0])
+  assume(t[0].field == 0)
+  assume(t[0].borrowingFunc() == 0)
+  assume(t[0].readCoroutine == 0)
+  // take(t[0]) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
+  assume(t[0].consumingGetter == 0) // expected-error {{'t.subscript' is borrowed and cannot be consumed}} expected-note {{consumed here}}
+  // assume(t[0].consumingFunc() == 0) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
 }
 func test(p: P) {
   borrow(p.data)
   take(p.data) // expected-error{{'p.data' is borrowed and cannot be consumed}} expected-note{{consumed here}}
+
+  borrow(p[0])
+  assume(p[0].field == 0)
+  assume(p[0].borrowingFunc() == 0)
+  assume(p[0].readCoroutine == 0)
+  // take(p[0]) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
+  assume(p[0].consumingGetter == 0) // expected-error {{'p.subscript' is borrowed and cannot be consumed}} expected-note {{consumed here}}
+  // assume(p[0].consumingFunc() == 0) // FIXME: the move-checker's diagnostics produced for this code are non-deterministic?
 }
 
diff --git a/test/SILOptimizer/moveonly_type_eliminator.sil b/test/SILOptimizer/moveonly_type_eliminator.sil
index 05297a652d4c9..6c9187cb5f86a 100644
--- a/test/SILOptimizer/moveonly_type_eliminator.sil
+++ b/test/SILOptimizer/moveonly_type_eliminator.sil
@@ -26,6 +26,8 @@ struct TrivialPair {
 
 sil @use_trivial : $@convention(thin) (Trivial) -> ()
 
+sil @readIndirectTrivial : $@convention(method) (@in_guaranteed Trivial) -> ()
+
 class Klass {
   func foo()
 }
@@ -674,3 +676,38 @@ bb0(%0 : $@thin Trivial.Type):
   %13 = tuple ()
   return %13 : $()
 }
+
+// Test deferred visitation of a store_borrow until both operands have been visited.
+//
+// CHECK-LABEL: sil hidden [ossa] @testLoadStoreBorrow : $@convention(thin) (Trivial) -> () {
+// CHECK: bb0(%0 : @noImplicitCopy @_eagerMove $Trivial):
+// CHECK: [[VAR:%[0-9]+]] = alloc_stack [var_decl] [moveable_value_debuginfo] $Trivial, var, name "c"
+// CHECK: store %0 to [trivial] [[VAR]] : $*Trivial
+// CHECK: [[ACCESS:%[0-9]+]] = begin_access [read] [static] [[VAR]] : $*Trivial
+// CHECK: [[LD:%[0-9]+]] = load [trivial] [[ACCESS]] : $*Trivial
+// CHECK: [[ARG:%[0-9]+]] = alloc_stack [moveable_value_debuginfo] $Trivial
+// CHECK: store [[LD]] to [trivial] [[ARG]] : $*Trivial
+// CHECK-NOT: borrow
+// CHECK-LABEL: } // end sil function 'testLoadStoreBorrow'
+sil hidden [ossa] @testLoadStoreBorrow : $@convention(thin) (Trivial) -> () {
+bb0(%0 : @noImplicitCopy @_eagerMove $Trivial):
+  %1 = alloc_stack [var_decl] $@moveOnly Trivial, var, name "c", type $@moveOnly Trivial
+  %2 = moveonlywrapper_to_copyable_addr %1
+  store %0 to [trivial] %2
+  %4 = begin_access [read] [static] %1
+  %5 = load_borrow %4
+  %6 = alloc_stack $@moveOnly Trivial
+  // This store_borrow has two move-only operands.
+  %7 = store_borrow %5 to %6
+  %8 = function_ref @readIndirectTrivial : $@convention(method) (@in_guaranteed Trivial) -> ()
+  %9 = moveonlywrapper_to_copyable_addr %7
+  %10 = apply %8(%9) : $@convention(method) (@in_guaranteed Trivial) -> ()
+  end_borrow %7
+  end_borrow %5
+  end_access %4
+  dealloc_stack %6
+  destroy_addr %1
+  dealloc_stack %1
+  %99 = tuple ()
+  return %99 : $()
+}
diff --git a/test/SILOptimizer/moveonly_unchecked_exclusivity.swift b/test/SILOptimizer/moveonly_unchecked_exclusivity.swift
new file mode 100644
index 0000000000000..01115806fba52
--- /dev/null
+++ b/test/SILOptimizer/moveonly_unchecked_exclusivity.swift
@@ -0,0 +1,25 @@
+// RUN: %target-swift-frontend -enforce-exclusivity=unchecked -emit-sil %s | %FileCheck %s
+
+struct Foo: ~Copyable {
+    var x: Any
+}
+
+final class Bar {
+    init() { fatalError() }
+
+    // Ensure that noncopyable bindings still get [unsafe] exclusivity markers
+    // and get checked properly by the move-only checker.
+
+    // Bar.foo.setter:
+    // CHECK-LABEL: sil {{.*}} @$s{{.*}}3BarC3foo{{.*}}vs
+    // CHECK:         [[FIELD:%.*]] = ref_element_addr {{.*}}, #Bar.foo
+    // CHECK:         [[FIELD_ACCESS:%.*]] = begin_access [modify] [unsafe] [[FIELD]]
+    // CHECK-NEXT:    destroy_addr [[FIELD_ACCESS]]
+    // CHECK-NEXT:    copy_addr [take] {{.*}} to [init] [[FIELD_ACCESS]]
+    // CHECK-NEXT:    end_access [[FIELD_ACCESS]]
+    // CHECK-NOT:     [[FIELD]]
+    // CHECK-NOT:     [[FIELD_ACCESS]]
+    // CHECK: } // end sil {{.*}} '$s{{.*}}3BarC3foo{{.*}}vs'
+
+    var foo: Foo
+}
diff --git a/test/SILOptimizer/mutable_span_bounds_check_tests.swift b/test/SILOptimizer/mutable_span_bounds_check_tests.swift
index db1de2c39c006..5b6544b2b69da 100644
--- a/test/SILOptimizer/mutable_span_bounds_check_tests.swift
+++ b/test/SILOptimizer/mutable_span_bounds_check_tests.swift
@@ -1,10 +1,10 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module-path %t/SpanExtras.swiftmodule %S/Inputs/SpanExtras.swift -enable-builtin-module  -enable-experimental-feature LifetimeDependence -O
-// RUN: %target-swift-frontend -I %t -O -emit-sil %s -enable-experimental-feature LifetimeDependence -disable-availability-checking | %FileCheck %s --check-prefix=CHECK-SIL 
-// RUN: %target-swift-frontend -I %t -O -emit-ir %s -enable-experimental-feature LifetimeDependence -disable-availability-checking | %FileCheck %s --check-prefix=CHECK-IR
+// RUN: %target-swift-frontend -emit-module-path %t/SpanExtras.swiftmodule %S/Inputs/SpanExtras.swift -enable-builtin-module  -enable-experimental-feature Lifetimes -O
+// RUN: %target-swift-frontend -I %t -O -emit-sil %s -enable-experimental-feature Lifetimes -disable-availability-checking | %FileCheck %s --check-prefix=CHECK-SIL 
+// RUN: %target-swift-frontend -I %t -O -emit-ir %s -enable-experimental-feature Lifetimes -disable-availability-checking | %FileCheck %s --check-prefix=CHECK-IR
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // REQUIRES: swift_stdlib_no_asserts, optimized_stdlib
 
@@ -44,7 +44,7 @@ public func span_zero_init(_ output: inout MutableSpan<Int>) {
 // CHECK-IR: define {{.*}} void @"$s31mutable_span_bounds_check_tests0B14_copy_elemwiseyy10SpanExtras07MutableH0VySiGz_s0H0VySiGtF"
 // CHECK-IR: vector.body
 // CHECK-IR: store <{{.*}}>
-@lifetime(output: copy output, copy input)
+@_lifetime(output: copy output, copy input)
 public func span_copy_elemwise(_ output: inout MutableSpan<Int>, _ input: Span<Int>) {
   precondition(output.count >= input.count)
   for i in input.indices {
@@ -66,7 +66,7 @@ public func span_copy_elemwise(_ output: inout MutableSpan<Int>, _ input: Span<I
 // CHECK-IR: define {{.*}} void @"$s31mutable_span_bounds_check_tests0B16_append_elemwiseyy10SpanExtras06OutputH0VySiGz_s0H0VySiGtF"
 // CHECK-IR: vector.body
 // CHECK-IR: store <{{.*}}>
-@lifetime(output: copy output, copy input)
+@_lifetime(output: copy output, copy input)
 public func span_append_elemwise(_ output: inout OutputSpan<Int>, _ input: Span<Int>) {
   for i in input.indices {
     output.append(input[i])
@@ -85,7 +85,7 @@ public func span_append_elemwise(_ output: inout OutputSpan<Int>, _ input: Span<
 // CHECK-IR: define {{.*}} void @"$s31mutable_span_bounds_check_tests0B12_sum_wo_trapyy10SpanExtras07MutableI0VySiGz_s0I0VySiGAItF"
 // CHECK-IR: vector.body
 // CHECK-IR: store <{{.*}}>
-@lifetime(output: copy output, copy input1, copy input2)
+@_lifetime(output: copy output, copy input1, copy input2)
 public func span_sum_wo_trap(_ output: inout MutableSpan<Int>, _ input1: Span<Int>, _ input2: Span<Int>) {
   precondition(input1.count == input2.count)
   precondition(output.count == input1.count)
@@ -100,7 +100,7 @@ public func span_sum_wo_trap(_ output: inout MutableSpan<Int>, _ input1: Span<In
 // CHECK-SIL-NOT: cond_fail {{.*}}, "precondition failure"
 // CHECK-SIL: cond_br
 // CHECK-SIL-LABEL: } // end sil function '$s31mutable_span_bounds_check_tests0B14_sum_with_trapyy10SpanExtras07MutableI0VySiGz_s0I0VySiGAItF'
-@lifetime(output: copy input1, copy input2)
+@_lifetime(output: copy input1, copy input2)
 public func span_sum_with_trap(_ output: inout MutableSpan<Int>, _ input1: Span<Int>, _ input2: Span<Int>) {
   precondition(input1.count == input2.count)
   precondition(output.count == input1.count)
diff --git a/test/SILOptimizer/ome_non_transparent.sil b/test/SILOptimizer/ome_non_transparent.sil
deleted file mode 100644
index 7a01cd2caa096..0000000000000
--- a/test/SILOptimizer/ome_non_transparent.sil
+++ /dev/null
@@ -1,19 +0,0 @@
-// RUN: %target-sil-opt -non-transparent-func-ownership-model-eliminator %s | %FileCheck %s
-
-sil_stage raw
-
-import Builtin
-
-// CHECK-LABEL: sil [transparent] [ossa] @foo : $@convention(thin) () -> () {
-sil [transparent] [ossa] @foo : $@convention(thin) () -> () {
-bb0:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil @bar : $@convention(thin) () -> () {
-sil [ossa] @bar : $@convention(thin) () -> () {
-bb0:
-  %9999 = tuple()
-  return %9999 : $()
-}
diff --git a/test/SILOptimizer/ome_strip_deserialize.sil b/test/SILOptimizer/ome_strip_deserialize.sil
index 195628852609f..2a042e611bb11 100644
--- a/test/SILOptimizer/ome_strip_deserialize.sil
+++ b/test/SILOptimizer/ome_strip_deserialize.sil
@@ -1,7 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -parse-sil -module-name OMEStripDeserializationInput %S/Inputs/ome_strip_deserialize_input.sil -emit-module -o %t/OMEStripDeserializationInput.swiftmodule
-// RUN: %target-sil-opt -non-transparent-func-ownership-model-eliminator -performance-linker -I %t %s | %FileCheck %s
-// RUN: %target-sil-opt -ownership-model-eliminator -performance-linker -I %t %s | %FileCheck --check-prefix=CHECK-STRIP-ALL %s
+// RUN: %target-sil-opt -ownership-model-eliminator -performance-linker -I %t %s | %FileCheck %s
 
 sil_stage canonical
 
@@ -11,22 +10,14 @@ import OMEStripDeserializationInput
 // ownership SIL.
 
 // CHECK-LABEL: sil public_external [serialized] @bar : $@convention(thin) () -> ()
-// CHECK: } // end sil function 'bar'
-
-// CHECK-STRIP-ALL-LABEL: sil public_external [serialized] @bar : $@convention(thin) () -> ()
-// CHECK-STRIP-ALL: } // end sil function 'bar'
+// CHECK:       } // end sil function 'bar'
 sil [ossa] @bar : $@convention(thin) () -> ()
 
-// CHECK-LABEL: sil public_external [transparent] [serialized] [ossa] @transparent_bar : $@convention(thin) () -> ()
-// CHECK: } // end sil function 'transparent_bar'
-
-// CHECK-STRIP-ALL-LABEL: sil public_external [transparent] [serialized] @transparent_bar : $@convention(thin) () -> ()
-// CHECK-STRIP-ALL: } // end sil function 'transparent_bar'
+// CHECK-LABEL: sil public_external [transparent] [serialized] @transparent_bar : $@convention(thin) () -> ()
+// CHECK:       } // end sil function 'transparent_bar'
 
 sil [transparent] [ossa] @transparent_bar : $@convention(thin) () -> ()
 
-// CHECK-LABEL: sil @foo : $@convention(thin) () -> () {
-// CHECK: } // end sil function 'foo'
 sil [ossa] @foo : $@convention(thin) () -> () {
 bb0:
   %0 = function_ref @bar : $@convention(thin) () -> ()
diff --git a/test/SILOptimizer/opaque_values_mandatory.sil b/test/SILOptimizer/opaque_values_mandatory.sil
index 7a5128afc550f..f30aec82a88cc 100644
--- a/test/SILOptimizer/opaque_values_mandatory.sil
+++ b/test/SILOptimizer/opaque_values_mandatory.sil
@@ -1,7 +1,7 @@
 // RUN: %target-sil-opt -diagnostics -enable-sil-opaque-values %s | \
 // RUN:     %target-sil-opt -Onone-performance -enable-sil-verify-all \
 // RUN:                     -enable-sil-opaque-values -emit-sorted-sil \
-// RUN:                     -enable-ossa-modules -enable-copy-propagation \
+// RUN:                     -enable-copy-propagation \
 // RUN:                     -enable-lexical-borrow-scopes | \
 // RUN:     %FileCheck %s
 //
diff --git a/test/SILOptimizer/opened_archetype_operands_tracking.sil b/test/SILOptimizer/opened_archetype_operands_tracking.sil
index 98ba22beddf5d..1ef870a3d097b 100644
--- a/test/SILOptimizer/opened_archetype_operands_tracking.sil
+++ b/test/SILOptimizer/opened_archetype_operands_tracking.sil
@@ -177,7 +177,7 @@ bb0(%0 : $*T, %1 : $Foo<T>):
 } // end sil function 'Foo_init'
 
 // P.foo()
-sil [always_inline] @P_foo : $@convention(method) <Self where Self : P> (@in_guaranteed Self) -> () {
+sil [heuristic_always_inline] @P_foo : $@convention(method) <Self where Self : P> (@in_guaranteed Self) -> () {
 bb0(%0 : $*Self):
   // function_ref Foo.__allocating_init(_:)
   %2 = function_ref @Foo_alloc_init : $@convention(method) <τ_0_0 where τ_0_0 : P> (@in τ_0_0, @thick Foo<τ_0_0>.Type) -> @owned Foo<τ_0_0>
diff --git a/test/SILOptimizer/optimal_arc.swift b/test/SILOptimizer/optimal_arc.swift
index dd82de7977705..579bbf648b0b6 100644
--- a/test/SILOptimizer/optimal_arc.swift
+++ b/test/SILOptimizer/optimal_arc.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -module-name test -O -emit-sil -O -primary-file %s | %FileCheck %s
+// RUN: %target-swift-frontend -module-name test -O -emit-sil -primary-file %s | %FileCheck %s
 
 // REQUIRES: optimized_stdlib,swift_stdlib_no_asserts
 
@@ -50,5 +50,25 @@ struct TestCollection: RandomAccessCollection, RangeReplaceableCollection {
   }
 }
 
+class C {
+  func foo() {}
+}
+
+struct S: ~Copyable {
+  var c: C
+
+  // Check that there is only a single release in the deinit.
+
+  // CHECK-LABEL: sil hidden @$s4test1SVfD :
+  // CHECK-NOT:     retain
+  // CHECK-NOT:     release
+  // CHECK:         apply
+  // CHECK:         release
+  // CHECK-NOT:     release
+  // CHECK:       } // end sil function '$s4test1SVfD'
+  deinit {
+    c.foo()
+  }
+}
 
 
diff --git a/test/SILOptimizer/optimize_copy_block.swift b/test/SILOptimizer/optimize_copy_block.swift
new file mode 100644
index 0000000000000..b8c973d660aa7
--- /dev/null
+++ b/test/SILOptimizer/optimize_copy_block.swift
@@ -0,0 +1,62 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -I %t %t/test.swift -O -emit-sil | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+//--- module.modulemap
+
+module CModule {
+  header "c-header.h"
+  export *
+}
+
+
+//--- c-header.h
+
+@import Foundation;
+
+@interface TestClass : NSObject
+- (void)callHandler1: (NS_NOESCAPE _Nonnull dispatch_block_t)block;
+- (void)callHandler2: (NS_NOESCAPE _Nonnull dispatch_block_t)block;
+- (void)callHandler3: (NS_NOESCAPE _Nonnull dispatch_block_t)block;
+@end
+
+
+//--- test.swift
+
+import CModule
+
+@objc @implementation
+extension TestClass {
+  // CHECK-LABEL: sil private [thunk] @$sSo9TestClassC4testE12callHandler1yyyyXEFTo :
+  // CHECK-NOT:     copy_block
+  // CHECK:         apply %0
+  // CHECK-NOT:     destroy_value
+  // CHECK:       } // end sil function '$sSo9TestClassC4testE12callHandler1yyyyXEFTo'
+  func callHandler1(_ handler: () -> Void) {
+    handler()
+  }
+
+  // CHECK-LABEL: sil private [thunk] @$sSo9TestClassC4testE12callHandler2yyyyXEFTo :
+  // CHECK-NOT:     copy_block
+  // CHECK:       } // end sil function '$sSo9TestClassC4testE12callHandler2yyyyXEFTo' 
+  func callHandler2(_ handler: () -> Void) {
+    callee(handler)
+  }
+
+  // CHECK-LABEL: sil private [thunk] @$sSo9TestClassC4testE12callHandler3yyyyXEFTo :
+  // CHECK-NOT:     copy_block
+  // CHECK:       } // end sil function '$sSo9TestClassC4testE12callHandler3yyyyXEFTo' 
+  func callHandler3(_ handler: () -> Void) {
+    callClosure {
+      handler()
+    }
+  }
+}
+
+@_silgen_name("callee")
+func callee(_ handler: () -> Void)
+
+@_silgen_name("callClosure")
+func callClosure(_ closure: () -> ())
diff --git a/test/SILOptimizer/optimize_hop_to_executor.sil b/test/SILOptimizer/optimize_hop_to_executor.sil
index 6f5991055b8e5..10620d4238b1f 100644
--- a/test/SILOptimizer/optimize_hop_to_executor.sil
+++ b/test/SILOptimizer/optimize_hop_to_executor.sil
@@ -1,6 +1,7 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -optimize-hop-to-executor  | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-function-isolation-info -enable-sil-verify-all %s -optimize-hop-to-executor  | %FileCheck %s
 
 // REQUIRES: concurrency
+// REQUIRES: asserts
 
 sil_stage canonical
 
@@ -13,6 +14,7 @@ actor MyActor {
 
 sil [ossa] @requiredToRunOnActor : $@convention(method) (@guaranteed MyActor) -> ()
 sil [ossa] @anotherAsyncFunction : $@convention(thin) @async () -> ()
+sil [ossa] @syncFunction : $@convention(thin) () -> ()
 
 // CHECK-LABEL: sil [ossa] @simpleRedundantActor : $@convention(method) @async (@guaranteed MyActor) -> () {
 // CHECK:       bb0(%0 : @guaranteed $MyActor):
@@ -302,3 +304,136 @@ bb0(%0 : @guaranteed $MyActor):
   %r = tuple ()
   return %r : $()
 }
+
+// CHECK-LABEL: sil [ossa] @simpleDCEAsync : $@convention(thin) @async (@guaranteed MyActor) -> () {
+// CHECK-NOT: hop_to_executor
+// CHECK: } // end sil function 'simpleDCEAsync'
+sil [ossa] @simpleDCEAsync : $@convention(thin) @async (@guaranteed MyActor) -> () {
+bb0(%0 : @guaranteed $MyActor):
+  hop_to_executor %0
+  %f = function_ref @anotherAsyncFunction : $@convention(thin) @async () -> ()
+  apply %f() : $@convention(thin) @async () -> ()
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @simpleCallerIsolationInheritingStopsDCE : $@convention(thin) @async (@guaranteed MyActor) -> () {
+// CHECK: hop_to_executor
+// CHECK: } // end sil function 'simpleCallerIsolationInheritingStopsDCE'
+sil [ossa] @simpleCallerIsolationInheritingStopsDCE : $@convention(thin) @async (@guaranteed MyActor) -> () {
+bb0(%0 : @guaranteed $MyActor):
+  hop_to_executor %0
+  %f = function_ref @anotherAsyncFunction : $@convention(thin) @async () -> ()
+  apply [callee_isolation=caller_isolation_inheriting] [caller_isolation=caller_isolation_inheriting] %f() : $@convention(thin) @async () -> ()
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// We should eliminate none of the hop_to_executor here since
+// caller_isolation_inheriting @async apply sites do not cross isolation
+// boundaries.
+//
+// CHECK-LABEL: sil [ossa] @simpleCallerIsolationInheritingStopsDCE2 : $@convention(thin) @async (@guaranteed MyActor, @guaranteed MyActor, @guaranteed MyActor) -> () {
+// CHECK: hop_to_executor
+// CHECK: hop_to_executor
+// CHECK: hop_to_executor
+// CHECK: } // end sil function 'simpleCallerIsolationInheritingStopsDCE2'
+sil [ossa] @simpleCallerIsolationInheritingStopsDCE2 : $@convention(thin) @async (@guaranteed MyActor, @guaranteed MyActor, @guaranteed MyActor) -> () {
+bb0(%0 : @guaranteed $MyActor, %1 : @guaranteed $MyActor, %2 : @guaranteed $MyActor):
+  hop_to_executor %0
+  %f = function_ref @anotherAsyncFunction : $@convention(thin) @async () -> ()
+  apply [callee_isolation=caller_isolation_inheriting] [caller_isolation=caller_isolation_inheriting] %f() : $@convention(thin) @async () -> ()
+  hop_to_executor %1
+  %f2 = function_ref @syncFunction : $@convention(thin) () -> ()
+  apply %f2() : $@convention(thin) () -> ()
+  apply [callee_isolation=caller_isolation_inheriting] [caller_isolation=caller_isolation_inheriting] %f() : $@convention(thin) @async () -> ()
+  hop_to_executor %2
+  apply %f2() : $@convention(thin) () -> () 
+  apply [callee_isolation=caller_isolation_inheriting] [caller_isolation=caller_isolation_inheriting] %f() : $@convention(thin) @async () -> ()
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @simpleWithoutCallerIsolationInheritingHaveDCE : $@convention(thin) @async (@guaranteed MyActor, @guaranteed MyActor, @guaranteed MyActor) -> () {
+// CHECK: bb0([[ARG1:%.*]] : @guaranteed $MyActor, [[ARG2:%.*]] : @guaranteed $MyActor, [[ARG3:%.*]] : @guaranteed $MyActor):
+// CHECK-NEXT:  // function_ref anotherAsyncFunction
+// CHECK-NEXT:  [[FUNC:%.*]] = function_ref @anotherAsyncFunction : $@convention(thin) @async () -> ()
+// CHECK-NEXT:  apply [[FUNC]]() : $@convention(thin) @async () -> ()
+// CHECK-NEXT:  hop_to_executor [[ARG2]]
+// CHECK-NEXT:  // function_ref syncFunction
+// CHECK-NEXT:  [[FUNC2:%.*]] = function_ref @syncFunction : $@convention(thin) () -> ()
+// CHECK-NEXT:  apply [[FUNC2]]() : $@convention(thin) () -> ()
+// CHECK-NEXT:  apply [[FUNC]]() : $@convention(thin) @async () -> ()
+// CHECK-NEXT:  hop_to_executor [[ARG3]]
+// CHECK-NEXT:  apply [[FUNC2]]() : $@convention(thin) () -> () 
+// CHECK-NEXT:  apply [[FUNC]]() : $@convention(thin) @async () -> ()
+// CHECK-NEXT:  apply [[FUNC]]() : $@convention(thin) @async () -> ()
+// CHECK: } // end sil function 'simpleWithoutCallerIsolationInheritingHaveDCE'
+sil [ossa] @simpleWithoutCallerIsolationInheritingHaveDCE : $@convention(thin) @async (@guaranteed MyActor, @guaranteed MyActor, @guaranteed MyActor) -> () {
+bb0(%0 : @guaranteed $MyActor, %1 : @guaranteed $MyActor, %2 : @guaranteed $MyActor):
+  hop_to_executor %0
+  %f = function_ref @anotherAsyncFunction : $@convention(thin) @async () -> ()
+  apply %f() : $@convention(thin) @async () -> ()
+  hop_to_executor %1
+  %f2 = function_ref @syncFunction : $@convention(thin) () -> ()
+  apply %f2() : $@convention(thin) () -> ()
+  apply %f() : $@convention(thin) @async () -> ()
+  hop_to_executor %2
+  apply %f2() : $@convention(thin) () -> ()
+  apply %f() : $@convention(thin) @async () -> ()
+  hop_to_executor %2
+  apply %f() : $@convention(thin) @async () -> ()
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// We do not allow for these to be propagated yet through caller isolation
+// inheriting, so we should have all of the hop_to_executor.
+//
+// CHECK-LABEL: sil [ossa] @callerIsolationInheritingStopsAllowsPropagating : $@convention(thin) @async (@guaranteed MyActor, @guaranteed MyActor, @guaranteed MyActor) -> () {
+// CHECK: bb0(
+// CHECK: hop_to_executor
+// CHECK-NOT: hop_to_executor
+// CHECK: } // end sil function 'callerIsolationInheritingStopsAllowsPropagating'
+sil [ossa] @callerIsolationInheritingStopsAllowsPropagating : $@convention(thin) @async (@guaranteed MyActor, @guaranteed MyActor, @guaranteed MyActor) -> () {
+bb0(%0 : @guaranteed $MyActor, %1 : @guaranteed $MyActor, %2 : @guaranteed $MyActor):
+  hop_to_executor %0
+  %f = function_ref @anotherAsyncFunction : $@convention(thin) @async () -> ()
+  apply [callee_isolation=caller_isolation_inheriting] [caller_isolation=caller_isolation_inheriting] %f() : $@convention(thin) @async () -> ()
+  hop_to_executor %0
+  %f2 = function_ref @syncFunction : $@convention(thin) () -> ()
+  apply %f2() : $@convention(thin) () -> ()
+  apply [callee_isolation=caller_isolation_inheriting] [caller_isolation=caller_isolation_inheriting] %f() : $@convention(thin) @async () -> ()
+  hop_to_executor %0
+  apply %f2() : $@convention(thin) () -> () 
+  apply [callee_isolation=caller_isolation_inheriting] [caller_isolation=caller_isolation_inheriting] %f() : $@convention(thin) @async () -> ()
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// Since we are caller isolation inheriting, make sure that we leave around the
+// hop_to_executor due to ehre elase. We do eliminate one of the hop_to_executor
+// though.
+//
+// CHECK: sil [isolation "caller_isolation_inheriting"] [ossa] @callerIsolationInheritingStopsReturnDeadEnd : $@convention(thin) @async (@sil_isolated @guaranteed MyActor) -> () {
+// CHECK: bb0(
+// CHECK-NEXT: tuple
+// CHECK-NEXT: return
+// CHECK: } // end sil function 'callerIsolationInheritingStopsReturnDeadEnd'
+sil [isolation "caller_isolation_inheriting"] [ossa] @callerIsolationInheritingStopsReturnDeadEnd : $@convention(thin) @async (@sil_isolated @guaranteed MyActor) -> () {
+bb0(%0 : @guaranteed $MyActor):
+  hop_to_executor %0
+  hop_to_executor %0
+  %9999 = tuple ()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @noIsolationStillRemoves : $@convention(thin) @async (@guaranteed MyActor, @guaranteed MyActor, @guaranteed MyActor) -> () {
+// CHECK-NOT: hop_to_executor
+// CHECK: } // end sil function 'noIsolationStillRemoves'
+sil [ossa] @noIsolationStillRemoves : $@convention(thin) @async (@guaranteed MyActor, @guaranteed MyActor, @guaranteed MyActor) -> () {
+bb0(%0 : @guaranteed $MyActor, %1 : @guaranteed $MyActor, %2 : @guaranteed $MyActor):
+  hop_to_executor %0
+  %9999 = tuple ()
+  return %9999 : $()
+}
diff --git a/test/SILOptimizer/optimize_keypath.swift b/test/SILOptimizer/optimize_keypath.swift
index db7acd3c8a4a9..6af9bd93cc538 100644
--- a/test/SILOptimizer/optimize_keypath.swift
+++ b/test/SILOptimizer/optimize_keypath.swift
@@ -3,8 +3,16 @@
 // RUN: %FileCheck %s < %t/output.sil
 // RUN: %FileCheck -check-prefix=CHECK-ALL %s < %t/output.sil
 
+// RUN: %target-swift-frontend -primary-file %s -O -sil-verify-all -swift-version 6 -Xllvm -sil-print-types -emit-sil >%t/output6.sil
+// RUN: %FileCheck %s < %t/output6.sil
+// RUN: %FileCheck -check-prefix=CHECK-ALL %s < %t/output6.sil
+
 // RUN: %target-build-swift -O %s -o %t/a.out
-// RUN: %target-run %t/a.out | %FileCheck %s -check-prefix=CHECK-OUTPUT
+// RUN: %target-run %t/a.out | %FileCheck %s -check-prefix=CHECK-OUTPUT -check-prefix=CHECK5-OUTPUT
+
+// RUN: %target-build-swift -swift-version 6 -O %s -o %t/a6.out
+// RUN: %target-run %t/a6.out | %FileCheck %s -check-prefix=CHECK-OUTPUT
+
 // REQUIRES: executable_test,optimized_stdlib
 // REQUIRES: CPU=arm64 || CPU=x86_64
 
@@ -28,7 +36,9 @@ struct GenStruct<T : P> : P {
   }
 }
 
+#if !swift(>=6)
 var numGenClassObjs = 0
+#endif
 
 final class GenClass<T : P> : P {
   var ct: T
@@ -39,11 +49,15 @@ final class GenClass<T : P> : P {
   init(_ ct: T) {
     self.ct = ct
     self.gs = .init(ct)
+#if !swift(>=6)
     numGenClassObjs += 1
+#endif
   }
 
   deinit {
+#if !swift(>=6)
     numGenClassObjs -= 1
+#endif
   }
 
   func modifyIt() {
@@ -63,7 +77,9 @@ final class DerivedClass2 : DerivedClass<Int> {
 
 final class SimpleClass : P {
   var i: Int
+#if !swift(>=6)
   static var numObjs = 0
+#endif
   
   var tuple = (0, 1)
   
@@ -78,11 +94,15 @@ final class SimpleClass : P {
   init(_ i: Int, nested: Int? = nil) {
     self.i = i
     self.opt = nested.map { Nested(i: $0) }
+#if !swift(>=6)
     Self.numObjs += 1
+#endif
   }
 
   deinit {
+#if !swift(>=6)
     Self.numObjs -= 1
+#endif
   }
 
   func modifyIt() {
@@ -422,7 +442,7 @@ func testModifyOptionalForceClass(_ s: inout SimpleClass) {
 //
 //     Check if value is null
 // CHECK: switch_enum [[O:%[0-9]+]]
-// CHECK: {{bb.}}:
+// CHECK: bb{{.*}}:
 //         Unwrap value
 //     CHECK: [[A1:%[0-9]+]] = alloc_stack
 //     CHECK: store [[O]] to [[A1]]
@@ -453,7 +473,7 @@ func testOptionalChain(_ s: SimpleStruct) -> Int? {
 // CHECK: [[E2:%[0-9]+]] = begin_access [read] [dynamic] [no_nested_conflict] [[E1]]
 //     Check if value is null
 // CHECK: switch_enum [[O:%[0-9]+]]
-// CHECK: {{bb.}}:
+// CHECK: bb{{.*}}:
 //         Unwrap value
 //     CHECK: [[A1:%[0-9]+]] = alloc_stack
 //     CHECK: store [[O]] to [[A1]]
@@ -483,7 +503,7 @@ func testOptionalChainClass(_ s: SimpleClass) -> Int? {
 //
 //     Check if value is null
 // CHECK: switch_enum [[O:%[0-9]+]]
-// CHECK: {{bb.}}:
+// CHECK: bb{{.*}}:
 //         Unwrap value
 //     CHECK: [[A1:%[0-9]+]] = alloc_stack
 //     CHECK: store [[O]] to [[A1]]
@@ -491,7 +511,7 @@ func testOptionalChainClass(_ s: SimpleClass) -> Int? {
 //
 //         Unwrap nested optional
 //     CHECK: switch_enum [[O2:%[0-9]+]]
-//     CHECK: {{bb.}}:
+//     CHECK: bb{{.*}}:
 //         CHECK: [[A2:%[0-9]+]] = alloc_stack
 //         CHECK: store [[O2]] to [[A2]]
 //         CHECK: [[U2:%[0-9]+]] = unchecked_take_enum_data_addr [[A2]]
@@ -705,9 +725,11 @@ func testit() {
 
 testit()
 
-// CHECK-OUTPUT: SimpleClass obj count: 0
+#if !swift(>=6)
+// CHECK5-OUTPUT: SimpleClass obj count: 0
 print("SimpleClass obj count: \(SimpleClass.numObjs)")
-// CHECK-OUTPUT: GenClass obj count: 0
+// CHECK5-OUTPUT: GenClass obj count: 0
 print("GenClass obj count: \(numGenClassObjs)")
+#endif
 
 
diff --git a/test/SILOptimizer/optimize_keypath_bug.swift b/test/SILOptimizer/optimize_keypath_bug.swift
index 0ce95478c83bd..e4a23fe066320 100644
--- a/test/SILOptimizer/optimize_keypath_bug.swift
+++ b/test/SILOptimizer/optimize_keypath_bug.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-sil -O  -enable-ossa-modules -sil-verify-all %s
+// RUN: %target-swift-frontend -emit-sil -O -sil-verify-all %s
 // REQUIRES: OS=macosx
 
 import Foundation
diff --git a/test/SILOptimizer/optionset.swift b/test/SILOptimizer/optionset.swift
index 91b7204633be0..d0d790ab11df2 100644
--- a/test/SILOptimizer/optionset.swift
+++ b/test/SILOptimizer/optionset.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend  -parse-as-library -primary-file %s -O -sil-verify-all -module-name=test -Xllvm -sil-print-types -emit-sil | grep -v debug_value | %FileCheck %s
-// RUN: %target-swift-frontend  -parse-as-library -primary-file %s -Osize -sil-verify-all -module-name=test -Xllvm -sil-print-types -emit-sil | grep -v debug_value | %FileCheck %s
+// RUN: %target-swift-frontend  -parse-as-library -primary-file %s -O -sil-verify-all -module-name=test -emit-sil | grep -v debug_value | %FileCheck %s
+// RUN: %target-swift-frontend  -parse-as-library -primary-file %s -Osize -sil-verify-all -module-name=test -emit-sil | grep -v debug_value | %FileCheck %s
 // REQUIRES: swift_stdlib_no_asserts,optimized_stdlib
 // REQUIRES: swift_in_compiler
 
@@ -15,8 +15,8 @@ public struct TestOptions: OptionSet {
 
 // CHECK-LABEL: sil_global hidden [let] @$s4test17globalTestOptionsAA0cD0Vvp : $TestOptions = {
 // CHECK:   [[CONST:%.*]] = integer_literal $Builtin.Int{{32|64}}, 15
-// CHECK:   [[INT:%.*]] = struct $Int (%0 : $Builtin.Int{{32|64}})
-// CHECK:   %initval = struct $TestOptions ([[INT]] : $Int)
+// CHECK:   [[INT:%.*]] = struct $Int (%0)
+// CHECK:   %initval = struct $TestOptions ([[INT]])
 let globalTestOptions: TestOptions = [.first, .second, .third, .fourth]
 
 // CHECK-LABEL: sil @$s4test17returnTestOptionsAA0cD0VyF
@@ -33,12 +33,22 @@ public func returnTestOptions() -> TestOptions {
 
 // CHECK-LABEL: sil @$s4test22returnEmptyTestOptionsAA0dE0VyF
 // CHECK:      bb0:
-// CHECK-NEXT:   integer_literal {{.*}}, 0
-// CHECK-NEXT:   struct $Int
-// CHECK:        builtin "onFastPath"() : $()
-// CHECK-NEXT:   struct $TestOptions
-// CHECK-NEXT:   return
+// CHECK-NEXT:   [[ZERO:%.*]] = integer_literal {{.*}}, 0
+// CHECK:        [[I:%.*]] = struct $Int ([[ZERO]]
+// CHECK:        [[T:%.*]] = struct $TestOptions
+// CHECK:        return [[T]]
 // CHECK:      } // end sil function '$s4test22returnEmptyTestOptionsAA0dE0VyF'
 public func returnEmptyTestOptions() -> TestOptions {
     return []
 }
+
+extension TestOptions {
+    // CHECK-LABEL: sil @$s4test11TestOptionsV12insertSecondyyF :
+    // CHECK-NOT:   bb1
+    // CHECK:         builtin "or
+    // CHECK-NOT:   bb1
+    // CHECK:       } // end sil function '$s4test11TestOptionsV12insertSecondyyF'
+    public mutating func insertSecond() {
+        insert(.second)
+    }
+}
diff --git a/test/SILOptimizer/ossa_lifetime_completion.sil b/test/SILOptimizer/ossa_lifetime_completion.sil
index 6a641adf2c065..47a7c26340f73 100644
--- a/test/SILOptimizer/ossa_lifetime_completion.sil
+++ b/test/SILOptimizer/ossa_lifetime_completion.sil
@@ -17,6 +17,12 @@ public enum FakeOptional<T> {
   case some(T)
 }
 
+public enum E<T> {
+  case a(T)
+  case b(T)
+  case c
+}
+
 sil @swift_asyncLet_finish : $@convention(thin) @async (Builtin.RawPointer, Builtin.RawPointer) -> ()
 sil @swift_asyncLet_get : $@convention(thin) @async (Builtin.RawPointer, Builtin.RawPointer) -> ()
 sil @getC : $@convention(thin) () -> (@owned C)
@@ -32,15 +38,15 @@ typealias AnyObject = Builtin.AnyObject
 
 protocol P : AnyObject {}
 
-// CHECK-LABEL: begin running test 1 of 1 on eagerConsumeOwnedArg: ossa_lifetime_completion with: @argument
+// CHECK-LABEL: begin running test 1 of 1 on eagerConsumeOwnedArg: ossa_complete_lifetime with: @argument
 // CHECK-LABEL: OSSA lifetime completion on liveness boundary: %0 = argument of bb0 : $C
 // CHECK: sil [ossa] @eagerConsumeOwnedArg : $@convention(thin) (@owned C) -> () {
 // CHECK: bb0(%0 : @_eagerMove @owned $C):
 // CHECK-NEXT:   destroy_value %0 : $C
-// CHECK-LABEL: end running test 1 of 1 on eagerConsumeOwnedArg: ossa_lifetime_completion with: @argument
+// CHECK-LABEL: end running test 1 of 1 on eagerConsumeOwnedArg: ossa_complete_lifetime with: @argument
 sil [ossa] @eagerConsumeOwnedArg : $@convention(thin) (@owned C) -> () {
 entry(%0 : @_eagerMove @owned $C):
-  specify_test "ossa_lifetime_completion @argument liveness"
+  specify_test "ossa_complete_lifetime @argument liveness"
   br exit
 
 exit:
@@ -48,7 +54,7 @@ exit:
   return %retval : $()
 }
 
-// CHECK-LABEL: begin running test 1 of 1 on lexicalOwnedArg: ossa_lifetime_completion with: @argument
+// CHECK-LABEL: begin running test 1 of 1 on lexicalOwnedArg: ossa_complete_lifetime with: @argument
 // CHECK: OSSA lifetime completion on availability boundary: %0 = argument of bb0 : $C                         // user: %4
 // CHECK: sil [ossa] @lexicalOwnedArg : $@convention(thin) (@owned C) -> () {
 // CHECK: bb0(%0 : @owned $C):
@@ -57,10 +63,10 @@ exit:
 // CHECK-NEXT:   destroy_value [dead_end] %0 : $C
 // CHECK-NEXT:   unreachable
 // CHECK: } // end sil function 'lexicalOwnedArg'
-// CHECK-LABEL: end running test 1 of 1 on lexicalOwnedArg: ossa_lifetime_completion with: @argument
+// CHECK-LABEL: end running test 1 of 1 on lexicalOwnedArg: ossa_complete_lifetime with: @argument
 sil [ossa] @lexicalOwnedArg : $@convention(thin) (@owned C) -> () {
 bb0(%0 : @owned $C):
-  specify_test "ossa_lifetime_completion @argument availability"
+  specify_test "ossa_complete_lifetime @argument availability"
   cond_br undef, bb1, bb2
 bb1:
   br bb3
@@ -79,7 +85,7 @@ bb3:
 // CHECK-LABEL: } // end sil function 'borrowTest'
 sil [ossa] @borrowTest : $@convention(method) (@owned C) -> () {
 bb0(%0 : @owned $C):
-  specify_test "ossa_lifetime_completion @instruction[0] availability"
+  specify_test "ossa_complete_lifetime @instruction[0] availability"
   %borrow = begin_borrow %0 : $C
   cond_br undef, bb1, bb2
 
@@ -104,7 +110,7 @@ bb3:
 // CHECK-LABEL: } // end sil function 'enumTest'
 sil [ossa] @enumTest : $@convention(method) (@guaranteed FakeOptional<C>) -> () {
 bb0(%0 : @guaranteed $FakeOptional<C>):
-  specify_test "ossa_lifetime_completion @instruction[0] liveness"
+  specify_test "ossa_complete_lifetime @instruction[0] liveness"
   %copy = copy_value %0 : $FakeOptional<C>
   %borrow = begin_borrow %copy : $FakeOptional<C>
   switch_enum %borrow : $FakeOptional<C>, case #FakeOptional.some!enumelt: bb1, case #FakeOptional.none!enumelt: bb2
@@ -123,11 +129,43 @@ bb3:
   return %r : $()
 }
 
+// CHECK-LABEL: sil [ossa] @enumTest_no_destroy : $@convention(method) (@guaranteed E<C>) -> () {
+// CHECK:       bb2(%{{[0-9]+}} : @guaranteed $C):
+// CHECK:         destroy_value [dead_end]
+// CHECK-NEXT:    unreachable
+// CHECK:       bb3:
+// CHECK:         end_lifetime
+// CHECK-NEXT:    br bb4
+// CHECK-LABEL: } // end sil function 'enumTest_no_destroy'
+sil [ossa] @enumTest_no_destroy : $@convention(method) (@guaranteed E<C>) -> () {
+bb0(%0 : @guaranteed $E<C>):
+  specify_test "ossa_complete_lifetime @instruction[0] liveness_no_destroy"
+  %copy = copy_value %0 : $E<C>
+  %borrow = begin_borrow %copy : $E<C>
+  switch_enum %borrow : $E<C>, case #E.a!enumelt: bb1, case #E.b!enumelt: bb2, case #E.c!enumelt: bb3
+
+bb1(%10 : @guaranteed $C):
+  end_borrow %borrow : $E<C>
+  destroy_value %copy : $E<C>
+  br bb4
+
+bb2(%15 : @guaranteed $C):
+  unreachable
+
+bb3:
+  end_borrow %borrow : $E<C>
+  br bb4
+
+bb4:
+  %r = tuple ()
+  return %r : $()
+}
+
 sil @use_guaranteed : $@convention(thin) (@guaranteed C) -> ()
 
 sil [ossa] @argTest : $@convention(method) (@owned C) -> () {
 bb0(%0 : @owned $C):
-  specify_test "ossa_lifetime_completion @argument availability"
+  specify_test "ossa_complete_lifetime @argument availability"
   debug_value %0 : $C
   cond_br undef, bb1, bb2
 
@@ -151,7 +189,7 @@ bb4:
 // Ensure no assert fires while inserting dead end blocks to the worklist
 sil [ossa] @testLexicalLifetimeCompletion : $@convention(thin) (@owned C) -> () {
 bb0(%0 : @owned $C):
-  specify_test "ossa_lifetime_completion @argument availability"
+  specify_test "ossa_complete_lifetime @argument availability"
   debug_value %0 : $C, let, name "newElements", argno 1
   cond_br undef, bb1, bb2
 
@@ -194,7 +232,7 @@ sil @foo : $@convention(thin) (@guaranteed C) -> ()
 // Ensure no assert fires while handling lifetime end of partial_apply
 sil [ossa] @testPartialApplyStack1 : $@convention(thin) (@guaranteed C) -> () {
 bb0(%0 : @guaranteed $C):
-  specify_test "ossa_lifetime_completion @instruction[0] availability"
+  specify_test "ossa_complete_lifetime @instruction[0] availability"
   %8 = copy_value %0 : $C
   %9 = begin_borrow %8 : $C
   %80 = function_ref @foo : $@convention(thin) (@guaranteed C) -> ()
@@ -218,7 +256,7 @@ bb3:
 // Ensure no assert fires while handling lifetime end of partial_apply
 sil [ossa] @testPartialApplyStack2 : $@convention(thin) (@owned C) -> () {
 bb0(%0 : @owned $C):
-  specify_test "ossa_lifetime_completion @instruction[1] availability"
+  specify_test "ossa_complete_lifetime @instruction[1] availability"
   %2 = alloc_stack $C
   %3 = copy_value %0 : $C
   store %0 to [init] %2
@@ -260,7 +298,7 @@ sil [ossa] @availability_boundary_1 : $@convention(thin) () -> () {
 entry:
   %value = apply undef() : $@convention(thin) () -> @owned C
   %lexical = move_value [lexical] %value : $C // required (for lexicality)
-  specify_test "ossa_lifetime_completion %lexical availability"
+  specify_test "ossa_complete_lifetime %lexical availability"
   br condition_1
 
 condition_1:
@@ -317,7 +355,7 @@ sil [ossa] @availability_boundary_2_after_loop : $@convention(thin) () -> () {
 entry:
   %value = apply undef() : $@convention(thin) () -> @owned C
   %lexical = move_value [lexical] %value : $C // required (for lexicality)
-  specify_test "ossa_lifetime_completion %lexical availability"
+  specify_test "ossa_complete_lifetime %lexical availability"
   br condition_1
 
 condition_1:
@@ -382,7 +420,7 @@ sil [ossa] @availability_boundary_3_after_loop : $@convention(thin) () -> () {
 entry:
   %value = apply undef() : $@convention(thin) () -> @owned C
   %lexical = move_value [lexical] %value : $C // required (for lexicality)
-  specify_test "ossa_lifetime_completion %lexical availability"
+  specify_test "ossa_complete_lifetime %lexical availability"
   br condition_1
 
 condition_1:
@@ -432,7 +470,7 @@ sil [ossa] @project_box_deadend : $@convention(thin) (@owned C) -> () {
 bb0(%0 : @owned $C):
   %2 = alloc_box ${ var C }
   %3 = begin_borrow %2 : ${ var C }
-  specify_test "ossa_lifetime_completion %3 availability"
+  specify_test "ossa_complete_lifetime %3 availability"
   %4 = project_box %3 : ${ var C }, 0
   store %0 to [init] %4 : $*C
   unreachable
@@ -460,7 +498,7 @@ entry(%ie : @owned $IndirectEnumNontrivialPayload):
   switch_enum %ie : $IndirectEnumNontrivialPayload, case #IndirectEnumNontrivialPayload.c!enumelt: one_case
 
 one_case(%box : @owned ${ var C }):
-  specify_test "ossa_lifetime_completion %box availability"
+  specify_test "ossa_complete_lifetime %box availability"
   %c_addr = project_box %box : ${ var C }, 0
   %c = load_borrow %c_addr : $*C
   cond_br undef, left, right
@@ -490,7 +528,7 @@ bb0:
   %callee_pa = partial_apply [callee_guaranteed] undef() : $@convention(thin) @async @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <()>
   %callee_noescape = convert_escape_to_noescape [not_guaranteed] %callee_pa : $@async @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <()> 
             to $@noescape @async @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <()>
-  specify_test "ossa_lifetime_completion %callee_noescape availability"
+  specify_test "ossa_complete_lifetime %callee_noescape availability"
   %async_let = builtin "startAsyncLetWithLocalBuffer"<()>(
             %task_options : $Optional<Builtin.RawPointer>, 
             %callee_noescape : $@noescape @async @callee_guaranteed @substituted <τ_0_0> () -> (@out τ_0_0, @error any Error) for <()>, 
@@ -506,16 +544,16 @@ bb0:
   return %retval : $()
 }
 
-// CHECK-LABEL: begin running test {{.*}} on alloc_box: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on alloc_box: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @alloc_box : {{.*}} {
 // CHECK:         [[BOX:%[^,]+]] = alloc_box
 // CHECK:         dealloc_box [dead_end] [[BOX]]
 // CHECK-LABEL: } // end sil function 'alloc_box'
-// CHECK-LABEL: end running test {{.*}} on alloc_box: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on alloc_box: ossa_complete_lifetime
 sil [ossa] @alloc_box : $@convention(thin) (@owned C) -> () {
 entry(%instance : @owned $C):
   %box = alloc_box ${ var C }
-  specify_test "ossa_lifetime_completion %box availability"
+  specify_test "ossa_complete_lifetime %box availability"
   %addr = project_box %box : ${ var C }, 0
   store %instance to [init] %addr : $*C
   unreachable
@@ -533,7 +571,7 @@ entry(%instance : @owned $C):
 sil [ossa] @begin_apply : $@convention(thin) () -> () {
 entry:
   (%_, %token) = begin_apply undef() : $@yield_once @convention(thin) () -> (@yields @in_guaranteed ())
-  specify_test "ossa_lifetime_completion %token availability"
+  specify_test "ossa_complete_lifetime %token availability"
   cond_br undef, left, right
 
 left:
@@ -548,7 +586,7 @@ right:
 // CHECK-LABEL: begin running test {{.*}} on loopy: liveness_partial_boundary_outside_users with: %o
 // CHECK:       end_borrow
 // CHECK-LABEL: end running test {{.*}} on loopy: liveness_partial_boundary_outside_users with: %o
-// CHECK-LABEL: begin running test {{.*}} on loopy: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on loopy: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @loopy : {{.*}} {
 // CHECK:         [[O:%[^,]+]] = apply undef
 // CHECK:         [[B:%[^,]+]] = begin_borrow [[O]]
@@ -558,13 +596,13 @@ right:
 // CHECK:       bb1:
 // CHECK:         br bb1
 // CHECK-LABEL: } // end sil function 'loopy'
-// CHECK-LABEL: end running test {{.*}} on loopy: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on loopy: ossa_complete_lifetime
 // CHECK-LABEL: begin running test {{.*}} on loopy: liveness_partial_boundary_outside_users with: %o
 // CHECK-NEXT:  end running test {{.*}} on loopy: liveness_partial_boundary_outside_users with: %o
 sil [ossa] @loopy : $@convention(thin) () -> () {
   %o = apply undef() : $@convention(thin) () -> (@owned C)
   specify_test "liveness_partial_boundary_outside_users %o"
-  specify_test "ossa_lifetime_completion %o availability"
+  specify_test "ossa_complete_lifetime %o availability"
   specify_test "liveness_partial_boundary_outside_users %o"
   %b = begin_borrow %o : $C
   end_borrow %b : $C
@@ -576,7 +614,7 @@ loop:
 
 sil [ossa] @loopyComplete : $@convention(thin) () -> () {
   %o = apply undef() : $@convention(thin) () -> (@owned C)
-  specify_test "ossa_lifetime_completion %o availability"
+  specify_test "ossa_complete_lifetime %o availability"
   specify_test "liveness_partial_boundary_outside_users %o"
   %b = begin_borrow %o : $C
   end_borrow %b : $C
@@ -588,16 +626,16 @@ loop:
 }
 
 // When there are no users in the loop, do not extend the lifetime into it.
-// CHECK-LABEL: begin running test {{.*}} on loopy_sometimes: ossa_lifetime_completion with: %c, availability
+// CHECK-LABEL: begin running test {{.*}} on loopy_sometimes: ossa_complete_lifetime with: %c, availability
 // CHECK-LABEL: sil [ossa] @loopy_sometimes : {{.*}} {
 // CHECK-NOT:     extend_lifetime
 // CHECK-LABEL: } // end sil function 'loopy_sometimes'
-// CHECK-LABEL: end running test {{.*}} on loopy_sometimes: ossa_lifetime_completion with: %c, availability
+// CHECK-LABEL: end running test {{.*}} on loopy_sometimes: ossa_complete_lifetime with: %c, availability
 // CHECK-LABEL: begin running test {{.*}} on loopy_sometimes: liveness_partial_boundary_outside_users with: %c
 // CHECK-NEXT:  end running test {{.*}} on loopy_sometimes: liveness_partial_boundary_outside_users with: %c
 sil [ossa] @loopy_sometimes : $@convention(thin) (@owned C) -> () {
 entry(%c : @owned $C):
-  specify_test "ossa_lifetime_completion %c availability"
+  specify_test "ossa_complete_lifetime %c availability"
   specify_test "liveness_partial_boundary_outside_users %c"
   cond_br undef, header, exit
 
@@ -614,17 +652,17 @@ exit:
 }
 
 // When there are no users in the loop, do not extend the lifetime into it.
-// CHECK-LABEL: begin running test {{.*}} on loopy_sometimes_guaranteed: ossa_lifetime_completion with: %b, availability
+// CHECK-LABEL: begin running test {{.*}} on loopy_sometimes_guaranteed: ossa_complete_lifetime with: %b, availability
 // CHECK-LABEL: sil [ossa] @loopy_sometimes_guaranteed : {{.*}} {
 // CHECK-NOT:     extend_lifetime
 // CHECK-LABEL: } // end sil function 'loopy_sometimes_guaranteed'
-// CHECK-LABEL: end running test {{.*}} on loopy_sometimes_guaranteed: ossa_lifetime_completion with: %b, availability
+// CHECK-LABEL: end running test {{.*}} on loopy_sometimes_guaranteed: ossa_complete_lifetime with: %b, availability
 // CHECK-LABEL: begin running test {{.*}} on loopy_sometimes_guaranteed: liveness_partial_boundary_outside_users with: %b
 // CHECK-LABEL: end running test {{.*}} on loopy_sometimes_guaranteed: liveness_partial_boundary_outside_users with: %b
 sil [ossa] @loopy_sometimes_guaranteed : $@convention(thin) (@owned C) -> () {
 entry(%c : @owned $C):
   %b = begin_borrow %c : $C
-  specify_test "ossa_lifetime_completion %b availability"
+  specify_test "ossa_complete_lifetime %b availability"
   specify_test "liveness_partial_boundary_outside_users %b"
   cond_br undef, header, exit
 
@@ -641,7 +679,7 @@ exit:
   return %retval : $()
 }
 
-// CHECK-LABEL: begin running test {{.*}} on loopy_sometimes_2: ossa_lifetime_completion with: %c, availability
+// CHECK-LABEL: begin running test {{.*}} on loopy_sometimes_2: ossa_complete_lifetime with: %c, availability
 // CHECK-LABEL: sil [ossa] @loopy_sometimes_2 : {{.*}} {
 // CHECK:       bb0([[O:%[^,]+]] :
 // CHECK:         cond_br undef, [[HEADER:bb[0-9]+]], [[EXIT:bb[0-9]+]]
@@ -655,10 +693,10 @@ exit:
 // CHECK:       [[EXIT]]:
 // CHECK:         destroy_value [[O]]
 // CHECK-LABEL: } // end sil function 'loopy_sometimes_2'
-// CHECK-LABEL: end running test {{.*}} on loopy_sometimes_2: ossa_lifetime_completion with: %c, availability
+// CHECK-LABEL: end running test {{.*}} on loopy_sometimes_2: ossa_complete_lifetime with: %c, availability
 sil [ossa] @loopy_sometimes_2 : $@convention(thin) (@owned C) -> () {
 entry(%c : @owned $C):
-  specify_test "ossa_lifetime_completion %c availability"
+  specify_test "ossa_complete_lifetime %c availability"
   specify_test "liveness_partial_boundary_outside_users %c"
   cond_br undef, header, exit
 
@@ -676,7 +714,7 @@ exit:
   return %retval : $()
 }
 
-// CHECK-LABEL: begin running test {{.*}} on loopy_sometimes_2_guaranteed: ossa_lifetime_completion with: %c, availability
+// CHECK-LABEL: begin running test {{.*}} on loopy_sometimes_2_guaranteed: ossa_complete_lifetime with: %c, availability
 // CHECK-LABEL: sil [ossa] @loopy_sometimes_2_guaranteed : {{.*}} {
 // CHECK:       bb0([[C:%[^,]+]] :
 // CHECK:         [[B:%[^,]+]] = begin_borrow [[C]]
@@ -692,13 +730,13 @@ exit:
 // CHECK:         end_borrow [[B]]
 // CHECK:         destroy_value [[C]]
 // CHECK-LABEL: } // end sil function 'loopy_sometimes_2_guaranteed'
-// CHECK-LABEL: end running test {{.*}} on loopy_sometimes_2_guaranteed: ossa_lifetime_completion with: %c, availability
+// CHECK-LABEL: end running test {{.*}} on loopy_sometimes_2_guaranteed: ossa_complete_lifetime with: %c, availability
 // CHECK-LABEL: begin running test {{.*}} on loopy_sometimes_2_guaranteed: liveness_partial_boundary_outside_users with: %c
 // CHECK-NEXT:  end running test {{.*}} on loopy_sometimes_2_guaranteed: liveness_partial_boundary_outside_users with: %c
 sil [ossa] @loopy_sometimes_2_guaranteed : $@convention(thin) (@owned C) -> () {
 entry(%c : @owned $C):
   %b = begin_borrow %c : $C
-  specify_test "ossa_lifetime_completion %c availability"
+  specify_test "ossa_complete_lifetime %c availability"
   specify_test "liveness_partial_boundary_outside_users %c"
   cond_br undef, header, exit
 
@@ -728,7 +766,7 @@ bb0(%existential : @owned $any P):
   return %ref_existential : $AnyObject
 }
 
-// CHECK-LABEL: begin running test {{.*}} on root_of_reborrow: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on root_of_reborrow: ossa_complete_lifetime
 // Verify that no instructions were inserted after backedge2's terminator.  (In
 // fact, if they were, the test would crash.)
 // CHECK-LABEL: sil [ossa] @root_of_reborrow : {{.*}} {
@@ -738,7 +776,7 @@ bb0(%existential : @owned $any P):
 // CHECK-NEXT:    destroy_value [[C0]]
 // CHECK-NEXT:    br
 // CHECK-LABEL: } // end sil function 'root_of_reborrow'
-// CHECK-LABEL: end running test {{.*}} on root_of_reborrow: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on root_of_reborrow: ossa_complete_lifetime
 sil [ossa] @root_of_reborrow : $@convention(thin) () -> () {
 entry:
   %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
@@ -760,14 +798,14 @@ backedge:
   br backedge2(%c1 : $C, %b1 : $C)
 backedge2(%c2 : @owned $C, %b2 : @reborrow $C):
   %b2f = borrowed %b2 : $C from (%c2 : $C)
-  specify_test "ossa_lifetime_completion %c2 availability"
+  specify_test "ossa_complete_lifetime %c2 availability"
   br header(%c2 : $C, %b2f : $C)
 exit:
   unreachable
 }
 
 
-// CHECK-LABEL: begin running test {{.*}} on test_borrowed_from: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on test_borrowed_from: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @test_borrowed_from : {{.*}} {
 // CHECK:       bb1([[A:%.*]] : @reborrow $C):
 // CHECK:         [[BF:%.*]] = borrowed [[A]] : $C from (%0 : $C)
@@ -775,7 +813,7 @@ exit:
 // CHECK-NEXT:    end_borrow [[BF]] : $C
 // CHECK-NEXT:    unreachable
 // CHECK-LABEL: } // end sil function 'test_borrowed_from'
-// CHECK-LABEL: end running test {{.*}} on test_borrowed_from: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on test_borrowed_from: ossa_complete_lifetime
 sil [ossa] @test_borrowed_from : $@convention(thin) (@owned C) -> @owned C {
 bb0(%0 : @owned $C):
   %1 = begin_borrow %0 : $C
@@ -783,7 +821,7 @@ bb0(%0 : @owned $C):
 
 bb1(%3 : @reborrow $C):
   %4 = borrowed %3 : $C from (%0 : $C)
-  specify_test "ossa_lifetime_completion %3 availability"
+  specify_test "ossa_complete_lifetime %3 availability"
   cond_br undef, bb2, bb3
 
 bb2:
@@ -794,7 +832,7 @@ bb3:
   return %0 : $C
 }
 
-// CHECK-LABEL: begin running test {{.*}} on store_borrow: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on store_borrow: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @store_borrow : {{.*}} {
 // CHECK:         [[TOKEN:%[^,]+]] = store_borrow
 // CHECK:         cond_br undef, {{bb[0-9]+}}, [[DIE:bb[0-9]+]]
@@ -802,10 +840,10 @@ bb3:
 // CHECK-NEXT:    end_borrow [[TOKEN]]
 // CHECK-NEXT:    unreachable
 // CHECK-LABEL: } // end sil function 'store_borrow'
-// CHECK-LABEL: end running test {{.*}} on store_borrow: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on store_borrow: ossa_complete_lifetime
 sil [ossa] @store_borrow : $@convention(thin) (@guaranteed C) -> () {
 entry(%instance : @guaranteed $C):
-  specify_test "ossa_lifetime_completion %token availability"
+  specify_test "ossa_complete_lifetime %token availability"
   %addr = alloc_stack $C
   %token = store_borrow %instance to %addr : $*C
   cond_br undef, exit, die
@@ -819,7 +857,7 @@ die:
   unreachable
 }
 
-// CHECK-LABEL: begin running test {{.*}} on load_borrow_of_store_borrow_1: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on load_borrow_of_store_borrow_1: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @load_borrow_of_store_borrow_1 : {{.*}} {
 // CHECK:         [[TOKEN:%[^,]+]] = store_borrow
 // CHECK:         [[LOAD:%[^,]+]] = load_borrow [[TOKEN]]
@@ -831,10 +869,10 @@ die:
 // CHECK-NEXT:    end_borrow [[TOKEN]]
 // CHECK-NEXT:    unreachable
 // CHECK-LABEL: } // end sil function 'load_borrow_of_store_borrow_1'
-// CHECK-LABEL: end running test {{.*}} on load_borrow_of_store_borrow_1: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on load_borrow_of_store_borrow_1: ossa_complete_lifetime
 sil [ossa] @load_borrow_of_store_borrow_1 : $@convention(thin) (@guaranteed C) -> () {
 entry(%instance : @guaranteed $C):
-  specify_test "ossa_lifetime_completion %token availability"
+  specify_test "ossa_complete_lifetime %token availability"
   %addr = alloc_stack $C
   %token = store_borrow %instance to %addr
   %load = load_borrow %token
@@ -852,7 +890,7 @@ die:
   unreachable
 }
 
-// CHECK-LABEL: begin running test {{.*}} on load_borrow_of_store_borrow_2: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on load_borrow_of_store_borrow_2: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @load_borrow_of_store_borrow_2 : {{.*}} {
 // CHECK:         [[TOKEN:%[^,]+]] = store_borrow
 // CHECK:         [[LOAD:%[^,]+]] = load_borrow [[TOKEN]]
@@ -864,10 +902,10 @@ die:
 // CHECK-NEXT:    end_borrow [[TOKEN]]
 // CHECK-NEXT:    unreachable
 // CHECK-LABEL: } // end sil function 'load_borrow_of_store_borrow_2'
-// CHECK-LABEL: end running test {{.*}} on load_borrow_of_store_borrow_2: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on load_borrow_of_store_borrow_2: ossa_complete_lifetime
 sil [ossa] @load_borrow_of_store_borrow_2 : $@convention(thin) (@guaranteed C) -> () {
 entry(%instance : @guaranteed $C):
-  specify_test "ossa_lifetime_completion %token availability"
+  specify_test "ossa_complete_lifetime %token availability"
   %addr = alloc_stack $C
   %token = store_borrow %instance to %addr
   %load = load_borrow %token
@@ -889,7 +927,7 @@ die:
 
 sil [ossa] @load_borrow_1 : $@convention(thin) (@in_guaranteed C) -> () {
 entry(%addr : $*C):
-  specify_test "ossa_lifetime_completion %load availability"
+  specify_test "ossa_complete_lifetime %load availability"
   %load = load_borrow %addr
   %borrow = begin_borrow %load
   cond_br undef, exit, die
@@ -903,7 +941,7 @@ die:
   unreachable
 }
 
-// CHECK-LABEL: begin running test {{.*}} on begin_access: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on begin_access: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @begin_access : {{.*}} {
 // CHECK:         [[TOKEN:%[^,]+]] = begin_access
 // CHECK:         cond_br undef, {{bb[0-9]+}}, [[DIE:bb[0-9]+]]
@@ -911,10 +949,10 @@ die:
 // CHECK-NEXT:    end_access [[TOKEN]]
 // CHECK-NEXT:    unreachable
 // CHECK-LABEL: } // end sil function 'begin_access'
-// CHECK-LABEL: end running test {{.*}} on begin_access: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on begin_access: ossa_complete_lifetime
 sil [ossa] @begin_access : $@convention(thin) (@guaranteed C) -> () {
 entry(%instance : @guaranteed $C):
-  specify_test "ossa_lifetime_completion %access availability"
+  specify_test "ossa_complete_lifetime %access availability"
   %addr = alloc_stack $C
   %access = begin_access [static] [read] %addr : $*C
   cond_br undef, exit, die
@@ -928,7 +966,7 @@ die:
   unreachable
 }
 
-// CHECK-LABEL: begin running test {{.*}} on load_borrow_of_begin_access: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on load_borrow_of_begin_access: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @load_borrow_of_begin_access : {{.*}} {
 // CHECK:         [[ACCESS:%[^,]+]] = begin_access
 // CHECK:         [[LOAD:%[^,]+]] = load_borrow [[ACCESS]]
@@ -940,10 +978,10 @@ die:
 // CHECK-NEXT:    end_access [[ACCESS]]
 // CHECK-NEXT:    unreachable
 // CHECK-LABEL: } // end sil function 'load_borrow_of_begin_access'
-// CHECK-LABEL: end running test {{.*}} on load_borrow_of_begin_access: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on load_borrow_of_begin_access: ossa_complete_lifetime
 sil [ossa] @load_borrow_of_begin_access : $@convention(thin) (@in_guaranteed C) -> () {
 entry(%addr : $*C):
-  specify_test "ossa_lifetime_completion %access availability"
+  specify_test "ossa_complete_lifetime %access availability"
   %access = begin_access [static] [read] %addr : $*C
   %load = load_borrow %access
   %borrow = begin_borrow %load
@@ -965,33 +1003,82 @@ struct Wrapper {
   var c: Klass
 }
 
-// CHECK-LABEL: begin running test {{.*}} on testInteriorMarkDepNonEscAddressValue: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on testInteriorMarkDepNonEscAddressValue: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @testInteriorMarkDepNonEscAddressValue : {{.*}} {
 // CHECK: mark_dependence [nonescaping]
 // CHECK: end_borrow
 // CHECK-LABEL: } // end sil function 'testInteriorMarkDepNonEscAddressValue'
-// CHECK-LABEL: end running test {{.*}} on testInteriorMarkDepNonEscAddressValue: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on testInteriorMarkDepNonEscAddressValue: ossa_complete_lifetime
 sil [ossa] @testInteriorMarkDepNonEscAddressValue : $@convention(thin) (@owned Wrapper, @inout Klass) -> () {
 bb0(%0 : @owned $Wrapper, %1 : $*Klass):
-  specify_test "ossa_lifetime_completion %2 liveness"
+  specify_test "ossa_complete_lifetime %2 liveness"
   %2 = begin_borrow %0 : $Wrapper
   %3 = struct_extract %2 : $Wrapper, #Wrapper.c
   %4 = mark_dependence [nonescaping] %1 : $*Klass on %3 : $Klass
   unreachable
 }
 
-// CHECK-LABEL: begin running test {{.*}} on testOwnedMarkDepNonEscAddressValue: ossa_lifetime_completion
+// CHECK-LABEL: begin running test {{.*}} on testOwnedMarkDepNonEscAddressValue: ossa_complete_lifetime
 // CHECK-LABEL: sil [ossa] @testOwnedMarkDepNonEscAddressValue : {{.*}} {
 // CHECK: end_borrow
 // CHECK: mark_dependence [nonescaping]
 // CHECK: destroy_value [dead_end] %0
 // CHECK-LABEL: } // end sil function 'testOwnedMarkDepNonEscAddressValue'
-// CHECK-LABEL: end running test {{.*}} on testOwnedMarkDepNonEscAddressValue: ossa_lifetime_completion
+// CHECK-LABEL: end running test {{.*}} on testOwnedMarkDepNonEscAddressValue: ossa_complete_lifetime
 sil [ossa] @testOwnedMarkDepNonEscAddressValue : $@convention(thin) (@owned Wrapper, @inout Klass) -> () {
 bb0(%0 : @owned $Wrapper, %1 : $*Klass):
-  specify_test "ossa_lifetime_completion %0 liveness"
+  specify_test "ossa_complete_lifetime %0 liveness"
   %2 = begin_borrow %0 : $Wrapper
   %3 = struct_extract %2 : $Wrapper, #Wrapper.c
   %4 = mark_dependence [nonescaping] %1 : $*Klass on %0 : $Wrapper
   unreachable
 }
+
+sil @get_wrapper : $@convention(thin) () -> @owned Wrapper
+sil @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+
+sil [ossa] [noinline] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+bb0(%0 : @guaranteed $Wrapper):
+  %2 = struct_extract %0, #Wrapper.c
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @test_borrow_accessor1 :
+// CHECK:  [[F:%.*]] = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:  [[A:%.*]] = apply [[F]]({{.*}}) : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:  end_borrow {{.*}}
+// CHECK:  destroy_value {{.*}}
+// CHECK:  unreachable
+// CHECK-LABEL: } // end sil function 'test_borrow_accessor1'
+sil [ossa] @test_borrow_accessor1 : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  specify_test "ossa_complete_lifetime @instruction[0] liveness"
+  %copy = copy_value %0
+  %1 = begin_borrow %copy
+  %2 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %3 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %4 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %5 = apply %4(%3) : $@convention(thin) (@guaranteed Klass) -> ()
+  unreachable
+}
+
+// CHECK-LABEL: sil [ossa] @test_borrow_accessor2 :
+// CHECK:  [[F:%.*]] = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:  [[A:%.*]] = apply [[F]]({{.*}}) : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:  end_borrow {{.*}}
+// CHECK:  destroy_value {{.*}}
+// CHECK:  unreachable
+// CHECK-LABEL: } // end sil function 'test_borrow_accessor2'
+sil [ossa] @test_borrow_accessor2 : $@convention(thin) () -> () {
+bb0:
+  specify_test "ossa_complete_lifetime @instruction[1] liveness"
+  %1 = function_ref @get_wrapper : $@convention(thin) () -> @owned Wrapper
+  %2 = apply %1() : $@convention(thin) () -> @owned Wrapper
+  %3 = begin_borrow %2
+  %4 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %5 = apply %4(%3) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %6 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %7 = apply %6(%5) : $@convention(thin) (@guaranteed Klass) -> ()
+  unreachable
+}
+
diff --git a/test/SILOptimizer/ossa_rauw_tests.sil b/test/SILOptimizer/ossa_rauw_tests.sil
index 0a24c7af567e3..d6bf4638b8660 100644
--- a/test/SILOptimizer/ossa_rauw_tests.sil
+++ b/test/SILOptimizer/ossa_rauw_tests.sil
@@ -302,52 +302,57 @@ bbExitBlock(%result : @owned $FakeOptional<Klass>):
   return %result : $FakeOptional<Klass>
 }
 
-// CHECK-LABEL: sil [ossa] @unowned_to_guaranteed_rauw_2 : $@convention(thin) (@guaranteed Klass) -> (Klass, Klass) {
+// CHECK-LABEL: sil [ossa] @owned_to_guaranteed_rauw_2 : $@convention(thin) (@guaranteed Klass) -> @owned (Klass, Klass) {
 // CHECK: bb0(
 // CHECK-NEXT: tuple
+// CHECK-NEXT: copy_value
 // CHECK-NEXT: return
-// CHECK: } // end sil function 'unowned_to_guaranteed_rauw_2'
-sil [ossa] @unowned_to_guaranteed_rauw_2 : $@convention(thin) (@guaranteed Klass) -> (Klass, Klass) {
+// CHECK: } // end sil function 'owned_to_guaranteed_rauw_2'
+sil [ossa] @owned_to_guaranteed_rauw_2 : $@convention(thin) (@guaranteed Klass) -> @owned (Klass, Klass) {
 bb0(%0 : @guaranteed $Klass):
   %1 = unchecked_bitwise_cast %0 : $Klass to $SubKlass
   %2 = unchecked_bitwise_cast %1 : $SubKlass to $Klass
   %3 = tuple(%2 : $Klass, %2 : $Klass)
-  return %3 : $(Klass, Klass)
+  %4 = copy_value %3
+  return %4 : $(Klass, Klass)
 }
 
-// CHECK-LABEL: sil [ossa] @unowned_to_guaranteed_rauw_2a : $@convention(thin) (@guaranteed Builtin.NativeObject) -> (Klass, Klass) {
+// CHECK-LABEL: sil [ossa] @owned_to_guaranteed_rauw_2a : $@convention(thin) (@guaranteed Builtin.NativeObject) -> @owned (Klass, Klass) {
 // CHECK: bb0(
 // CHECK-NEXT: unchecked_ref_cast
 // CHECK-NEXT: tuple
+// CHECK-NEXT: copy_value
 // CHECK-NEXT: return
-// CHECK: } // end sil function 'unowned_to_guaranteed_rauw_2a'
-sil [ossa] @unowned_to_guaranteed_rauw_2a : $@convention(thin) (@guaranteed Builtin.NativeObject) -> (Klass, Klass) {
+// CHECK: } // end sil function 'owned_to_guaranteed_rauw_2a'
+sil [ossa] @owned_to_guaranteed_rauw_2a : $@convention(thin) (@guaranteed Builtin.NativeObject) -> @owned (Klass, Klass) {
 bb0(%0 : @guaranteed $Builtin.NativeObject):
   %0a = unchecked_ref_cast %0 : $Builtin.NativeObject to $Klass
   %1 = unchecked_bitwise_cast %0a : $Klass to $SubKlass
   %2 = unchecked_bitwise_cast %1 : $SubKlass to $Klass
   %3 = tuple(%2 : $Klass, %2 : $Klass)
-  return %3 : $(Klass, Klass)
+  %4 = copy_value %3
+  return %4 : $(Klass, Klass)
 }
 
 // We need the unchecked_ownership_conversion since our base value is
 // guaranteed, not a function argument, and our user is a function exiting
 // terminator.
 //
-// CHECK-LABEL: sil [ossa] @unowned_to_guaranteed_rauw_2b : $@convention(thin) (@guaranteed Builtin.NativeObject) -> Klass {
+// CHECK-LABEL: sil [ossa] @owned_to_guaranteed_rauw_2b : $@convention(thin) (@guaranteed Builtin.NativeObject) -> @owned Klass {
 // CHECK: bb0(
 // CHECK-NEXT: unchecked_ref_cast
+// CHECK-NEXT: copy_value
 // CHECK-NEXT: return
-// CHECK: } // end sil function 'unowned_to_guaranteed_rauw_2b'
-sil [ossa] @unowned_to_guaranteed_rauw_2b : $@convention(thin) (@guaranteed Builtin.NativeObject) -> Klass {
+// CHECK: } // end sil function 'owned_to_guaranteed_rauw_2b'
+sil [ossa] @owned_to_guaranteed_rauw_2b : $@convention(thin) (@guaranteed Builtin.NativeObject) -> @owned Klass {
 bb0(%0 : @guaranteed $Builtin.NativeObject):
   %0a = unchecked_ref_cast %0 : $Builtin.NativeObject to $Klass
   %1 = unchecked_bitwise_cast %0a : $Klass to $SubKlass
   %2 = unchecked_bitwise_cast %1 : $SubKlass to $Klass
-  return %2 : $Klass
+  %3 = copy_value %2
+  return %3 : $Klass
 }
 
-
 // CHECK-LABEL: sil [ossa] @unowned_to_guaranteed_rauw_2_loop : $@convention(thin) (@guaranteed Klass) -> @owned FakeOptional<(Klass, Klass)> {
 // CHECK: bb0([[ARG:%.*]] : @guaranteed $Klass):
 // CHECK-NOT: unchecked_bitwise_cast
@@ -404,15 +409,17 @@ bbExitBlock(%result : @owned $FakeOptional<(Klass, Klass)>):
   return %result : $FakeOptional<(Klass, Klass)>
 }
 
-// CHECK-LABEL: sil [ossa] @unowned_to_guaranteed_rauw_3 : $@convention(thin) (@guaranteed Klass) -> Klass {
+// CHECK-LABEL: sil [ossa] @owned_to_guaranteed_rauw_3 : $@convention(thin) (@guaranteed Klass) -> @owned Klass {
 // CHECK: bb0(
+// CHECK-NEXT: copy_value
 // CHECK-NEXT: return
-// CHECK: } // end sil function 'unowned_to_guaranteed_rauw_3'
-sil [ossa] @unowned_to_guaranteed_rauw_3 : $@convention(thin) (@guaranteed Klass) -> Klass {
+// CHECK: } // end sil function 'owned_to_guaranteed_rauw_3'
+sil [ossa] @owned_to_guaranteed_rauw_3 : $@convention(thin) (@guaranteed Klass) -> @owned Klass {
 bb0(%0 : @guaranteed $Klass):
   %1 = unchecked_bitwise_cast %0 : $Klass to $SubKlass
   %2 = unchecked_bitwise_cast %1 : $SubKlass to $Klass
-  return %2 : $Klass
+  %3 = copy_value %2
+  return %3 : $Klass
 }
 
 //===---
diff --git a/test/SILOptimizer/outliner.swift b/test/SILOptimizer/outliner.swift
index 184f932f5eaa3..ccfdeebe099f0 100644
--- a/test/SILOptimizer/outliner.swift
+++ b/test/SILOptimizer/outliner.swift
@@ -1,8 +1,6 @@
 // RUN: %target-swift-frontend -Osize -import-objc-header %S/Inputs/Outliner.h %s -Xllvm -sil-print-types -emit-sil -enforce-exclusivity=unchecked -enable-copy-propagation | %FileCheck %s
 // RUN: %target-swift-frontend -Osize -g -import-objc-header %S/Inputs/Outliner.h %s -Xllvm -sil-print-types -emit-sil -enforce-exclusivity=unchecked -enable-copy-propagation | %FileCheck %s
 
-// RUN: %target-swift-frontend -Osize -import-objc-header %S/Inputs/Outliner.h %s -Xllvm -sil-print-types -emit-sil -enforce-exclusivity=unchecked -enable-copy-propagation -enable-ossa-modules | %FileCheck %s
-// RUN: %target-swift-frontend -Osize -g -import-objc-header %S/Inputs/Outliner.h %s -Xllvm -sil-print-types -emit-sil -enforce-exclusivity=unchecked -enable-copy-propagation -enable-ossa-modules | %FileCheck %s
 // REQUIRES: objc_interop
 // REQUIRES: optimized_stdlib
 // REQUIRES: swift_in_compiler
diff --git a/test/SILOptimizer/ownership_liveness_unit.sil b/test/SILOptimizer/ownership_liveness_unit.sil
index ea968358d8050..619c80f52f62b 100644
--- a/test/SILOptimizer/ownership_liveness_unit.sil
+++ b/test/SILOptimizer/ownership_liveness_unit.sil
@@ -1,5 +1,5 @@
 // RUN: %target-sil-opt -sil-print-types -update-borrowed-from -test-runner \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: %s -o /dev/null 2>&1 | %FileCheck %s
 //
 // TODO: when complete lifetime verification become the default for SIL verification,
@@ -7,7 +7,7 @@
 // -disable-ownership-verification
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 sil_stage canonical
 
@@ -39,13 +39,12 @@ sil @getC : $@convention(thin) () -> @owned C
 struct NE: ~Escapable {
   var object: C
 
-  @lifetime(borrow object)
+  @_lifetime(borrow object)
   init(object: borrowing C) { self.object = copy object }
 }
 
 sil [ossa] @useCAddress : $@convention(thin) (@inout_aliasable C) -> ()
 
-
 // =============================================================================
 // LinearLiveness
 // =============================================================================
@@ -2139,3 +2138,96 @@ exit:
   %retval = tuple ()
   return %retval : $()
 }
+
+class Klass {
+}
+
+public struct Wrapper {
+  var _k: Klass
+  var i: Int
+}
+
+sil @get_wrapper : $@convention(thin) () -> @owned Wrapper
+sil @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+
+sil [ossa] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+bb0(%0 : @guaranteed $Wrapper):
+  %2 = struct_extract %0, #Wrapper._k
+  return %2
+}
+
+// CHECK: begin running test 1 of 2 on test_borrow_accessor1: interior_liveness with: %1
+// CHECK: sil [ossa] @test_borrow_accessor1 : $@convention(thin) (@owned Wrapper) -> () {
+// CHECK: bb0(%0 : @owned $Wrapper):
+// CHECK:   %1 = copy_value %0 : $Wrapper
+// CHECK:   %2 = begin_borrow %1 : $Wrapper
+// CHECK:   %3 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   %4 = apply %3(%2) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   %5 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:   %6 = apply %5(%4) : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:   unreachable
+// CHECK: }
+// CHECK: Interior liveness:   %2 = begin_borrow %1 : $Wrapper
+// CHECK: bb0: LiveWithin
+// CHECK: regular user:   %4 = apply %3(%2) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK: regular user:   %6 = apply %5(%4) : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK: Complete liveness
+// CHECK: last user:   %6 = apply %5(%4) : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK: end running test 1 of 2 on test_borrow_accessor1: interior_liveness with: %1
+sil [ossa] @test_borrow_accessor1 : $@convention(thin) (@owned Wrapper) -> () {
+bb0(%0 : @owned $Wrapper):
+  specify_test "interior_liveness %1"
+  specify_test "interior_liveness_swift %1"
+  %copy = copy_value %0
+  %1 = begin_borrow %copy
+  %2 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %3 = apply %2(%1) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %4 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %5 = apply %4(%3) : $@convention(thin) (@guaranteed Klass) -> ()
+  unreachable
+}
+
+// CHECK: begin running test 1 of 2 on test_borrow_accessor2: interior_liveness with: %3
+// CHECK: sil [ossa] @test_borrow_accessor2 : $@convention(thin) () -> () {
+// CHECK: bb0:
+// CHECK:   %0 = function_ref @get_wrapper : $@convention(thin) () -> @owned Wrapper
+// CHECK:   %1 = apply %0() : $@convention(thin) () -> @owned Wrapper
+// CHECK:   %2 = begin_borrow %1 : $Wrapper
+// CHECK:   %3 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   %4 = apply %3(%2) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK:   %5 = copy_value %4 : $Klass
+// CHECK:   %6 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:   %7 = apply %6(%5) : $@convention(thin) (@guaranteed Klass) -> ()
+// CHECK:   unreachable
+// CHECK: }
+// CHECK: Interior liveness:   %2 = begin_borrow %1 : $Wrapper
+// CHECK: bb0: LiveWithin
+// CHECK: regular user:   %4 = apply %3(%2) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK: regular user:   %5 = copy_value %4 : $Klass
+// CHECK: Complete liveness
+// CHECK: last user:   %5 = copy_value %4 : $Klass
+// CHECK: end running test 1 of 2 on test_borrow_accessor2: interior_liveness with: %3
+// CHECK: begin running test 2 of 2 on test_borrow_accessor2: interior_liveness_swift with: %3
+// CHECK: Interior liveness:   %2 = begin_borrow %1 : $Wrapper
+// CHECK: begin:      %2 = begin_borrow %1 : $Wrapper
+// CHECK: ends:       %5 = copy_value %4 : $Klass
+// CHECK: exits:
+// CHECK: interiors:  %4 = apply %3(%2) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+// CHECK: last user:   %5 = copy_value %4 : $Klass
+// CHECK: end running test 2 of 2 on test_borrow_accessor2: interior_liveness_swift with: %3
+
+sil [ossa] @test_borrow_accessor2 : $@convention(thin) () -> () {
+bb0:
+  specify_test "interior_liveness %3"
+  specify_test "interior_liveness_swift %3"
+  %1 = function_ref @get_wrapper : $@convention(thin) () -> @owned Wrapper
+  %2 = apply %1() : $@convention(thin) () -> @owned Wrapper
+  %3 = begin_borrow %2
+  %4 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %5 = apply %4(%3) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %copy = copy_value %5
+  %6 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %7 = apply %6(%copy) : $@convention(thin) (@guaranteed Klass) -> ()
+  unreachable
+}
+
diff --git a/test/SILOptimizer/ownership_utils/address_ownership_live_range.sil b/test/SILOptimizer/ownership_utils/address_ownership_live_range.sil
index 78b56ec3e6f9c..bc9c3d4ed06bb 100644
--- a/test/SILOptimizer/ownership_utils/address_ownership_live_range.sil
+++ b/test/SILOptimizer/ownership_utils/address_ownership_live_range.sil
@@ -1,20 +1,33 @@
-// RUN: %target-sil-opt -test-runner %s -o /dev/null 2>&1 | %FileCheck %s
+// RUN: %target-sil-opt -test-runner \
+// RUN: -enable-experimental-feature Lifetimes \
+// RUN: %s -o /dev/null 2>&1 | %FileCheck %s
 
-sil_stage canonical
+// REQUIRES: swift_feature_Lifetimes
+
+sil_stage raw
 
 import Builtin
+import Swift
 
 class C {}
 class D {
   var object: C
 }
 
+struct S {
+  let c: C
+}
+
+struct MutNE: ~Copyable & ~Escapable {}
+
+sil @getMutNE : $@convention(thin) (@inout S) -> @lifetime(borrow 0) @owned MutNE
+
 // An address live range can be extended by a dependent value.
 //
 // CHECK-LABEL: testMarkDepAddressBase: address_ownership_live_range with: %f0
 // CHECK-NEXT: Address:   [[F0:%.*]] = ref_element_addr %0 : $D, #D.object
 // CHECK-NEXT: Base: class  -   [[F0]] = ref_element_addr %0 : $D, #D.object
-// CHECK-NEXT: borrow: functionArgument(%0 = argument of bb0 : $D
+// CHECK:      borrow: functionArgument(%0 = argument of bb0 : $D
 // CHECK-NEXT: begin:      [[F0]] = ref_element_addr %0 : $D, #D.object
 // CHECK-NEXT: ends:       end_borrow %{{.*}} : $C
 // CHECK-NEXT: exits:
@@ -26,10 +39,50 @@ sil [ossa] @testMarkDepAddressBase : $@convention(thin) (@guaranteed D, @guarant
 bb0(%0 : @guaranteed $D, %1 : @guaranteed $D):
   %f0 = ref_element_addr %0 : $D, #D.object
   %f1 = ref_element_addr %1 : $D, #D.object
-  specify_test "address_ownership_live_range %f0"
+  specify_test "address_ownership_live_range %f0 %f0"
   %dependence = mark_dependence %f1 on %f0
   %load = load_borrow %dependence
   end_borrow %load
   %99 = tuple()
   return %99 : $()
 }
+
+// CHECK-LABEL: testInoutAtModify: address_ownership_live_range
+// CHECK: Address: %0 = argument of bb0 : $*S
+// CHECK: Begin:   [[ACCESS:%[0-9]+]] = begin_access [modify] [unknown] %0 : $*S
+// CHECK: local:   %0 = argument of bb0 : $*S
+// CHECK: begin:   %{{.*}} = alloc_box ${ let MutNE }, let, name "ne"
+// CHECK: ends:    unreachable
+// CHECK:          return
+// CHECK: exits:
+// CHECK: interiors:  end_access
+// CHECK-LABEL: testInoutAtModify: address_ownership_live_range
+sil hidden [ossa] @testInoutAtModify : $@convention(thin) (@inout S) -> () {
+bb0(%0 : $*S):
+  %1 = alloc_box ${ let MutNE }, let, name "ne"
+  %2 = begin_borrow [lexical] [var_decl] %1
+  %3 = project_box %2, 0
+  %4 = begin_access [modify] [unknown] %0
+  specify_test "address_ownership_live_range %0 %4"
+
+  %6 = function_ref @getMutNE : $@convention(thin) (@inout S) -> @lifetime(borrow 0) @owned MutNE
+  %7 = apply %6(%4) : $@convention(thin) (@inout S) -> @lifetime(borrow 0) @owned MutNE
+  store %7 to [init] %3
+  end_access %4
+  %10 = mark_unresolved_non_copyable_value [no_consume_or_assign] %3
+  %11 = load_borrow %10
+  cond_br undef, bb1, bb2
+
+bb1:
+  end_borrow %11
+  end_borrow %2
+  destroy_value %1
+  %15 = tuple ()
+  return %15
+
+bb2:
+  end_borrow %11
+  end_borrow %2
+  dealloc_box [dead_end] %1
+  unreachable
+}
diff --git a/test/SILOptimizer/package-cmo-inlining-pass.swift b/test/SILOptimizer/package-cmo-inlining-pass.swift
index bd73a456ce051..c8221c7ab289f 100644
--- a/test/SILOptimizer/package-cmo-inlining-pass.swift
+++ b/test/SILOptimizer/package-cmo-inlining-pass.swift
@@ -40,13 +40,10 @@ package struct PkgStruct {
 // CHECK: *** SIL function after {{.*}} EarlyPerfInliner (early-inline)
 // CHECK: sil package [ossa] @$s3Lib3fooyS2iF : $@convention(thin) (Int) -> Int {
 // CHECK:   [[PKG_ALLOC:%.*]] = alloc_stack $PkgStruct
-// CHECK:   [[PKG_INIT:%.*]] = alloc_stack [var_decl] $PkgStruct, var, name "self"
-// CHECK:   [[FIELD1_IVAR:%.*]] = struct_element_addr [[PKG_INIT]] : $*PkgStruct, #PkgStruct.field1
+// CHECK:   [[FIELD1_IVAR:%.*]] = struct_element_addr [[PKG_ALLOC]] : $*PkgStruct, #PkgStruct.field1
 // CHECK:   store {{.*}} to [trivial] [[FIELD1_IVAR]] : $*Int
-// CHECK:   [[FIELD2_IVAR:%.*]] = struct_element_addr [[PKG_INIT]] : $*PkgStruct, #PkgStruct.field2
+// CHECK:   [[FIELD2_IVAR:%.*]] = struct_element_addr [[PKG_ALLOC]] : $*PkgStruct, #PkgStruct.field2
 // CHECK:   store {{.*}} to [trivial] [[FIELD2_IVAR]] : $*Int
-// CHECK:   [[PKG_STR:%.*]] = load [trivial] [[PKG_INIT]]
-// CHECK:   store [[PKG_STR]] to [trivial] [[PKG_ALLOC]] : $*PkgStruct
 // CHECK:   [[FIELD1:%.*]] = struct_element_addr [[PKG_ALLOC]] : $*PkgStruct, #PkgStruct.field1
 // CHECK:   load [trivial] [[FIELD1]] : $*Int
 // CHECK:   [[FIELD2:%.*]] = struct_element_addr [[PKG_ALLOC]] : $*PkgStruct, #PkgStruct.field2
diff --git a/test/SILOptimizer/package-cmo-serialize-tables.swift b/test/SILOptimizer/package-cmo-serialize-tables.swift
index 47bc903d013f2..f54e02010d4b9 100644
--- a/test/SILOptimizer/package-cmo-serialize-tables.swift
+++ b/test/SILOptimizer/package-cmo-serialize-tables.swift
@@ -16,10 +16,11 @@
 // RUN: %FileCheck %s --check-prefix=CHECK-MAIN < %t/Main.sil
 
 // REQUIRES: swift_in_compiler
+// REQUIRES: swift_stdlib_no_asserts,optimized_stdlib
 
 // Temporarily disabling on watchOS (both arm64_32 & armv7k):
 // rdar://140330692 (🟠 OSS Swift CI: oss-swift_tools-RA_stdlib-DA_test-device-non_executable failed...
-// UNSUPPORTED: OS=watchos
+// UNSUPPORTED: OS=watchos, OS=linux-androideabi
 
 //--- main.swift
 
@@ -275,7 +276,7 @@ public struct PubStruct: PubProto {
   // protocol witness for static PubProto.root.getter in conformance PubStruct
   // CHECK-DAG: sil shared [transparent] [serialized] [thunk] [canonical] [ossa] @$s3Lib9PubStructVAA0B5ProtoA2aDP4roots6UInt16VvgZTW : $@convention(witness_method: PubProto) (@thick PubStruct.Type) -> UInt16 {
   // CHECK-DAG: function_ref @$s3Lib9PubStructV4roots6UInt16VvgZ : $@convention(method) (@thin PubStruct.Type) -> UInt16
-  // CHECK-DAG: sil [canonical] @$s3Lib9PubStructV4roots6UInt16VvgZ : $@convention(method) (@thin PubStruct.Type) -> UInt16
+  // CHECK-DAG: sil [serialized_for_package] [canonical] [ossa] @$s3Lib9PubStructV4roots6UInt16VvgZ : $@convention(method) (@thin PubStruct.Type) -> UInt16
   public static let root: UInt16 = 1 << 0
 
   // CHECK-DAG: sil shared [transparent] [serialized] [thunk] [canonical] [ossa] @$s3Lib9PubStructVAA0B5ProtoA2aDP3envs6UInt16VvgTW : $@convention(witness_method: PubProto) (@in_guaranteed PubStruct) -> UInt16 {
@@ -365,7 +366,7 @@ package class PkgKlassZ: PkgProto {
   // protocol witness for static PkgProto.root.getter in conformance PkgKlassZ
   // CHECK-DAG: sil shared [transparent] [serialized] [thunk] [canonical] [ossa] @$s3Lib9PkgKlassZCAA0B5ProtoA2aDP4roots6UInt16VvgZTW : $@convention(witness_method: PkgProto) (@thick PkgKlassZ.Type) -> UInt16 {
   // CHECK-DAG: function_ref @$s3Lib9PkgKlassZC4roots6UInt16VvgZ : $@convention(method) (@thick PkgKlassZ.Type) -> UInt16
-  // CHECK-DAG: sil package_external [canonical] @$s3Lib9PkgKlassZC4roots6UInt16VvgZ : $@convention(method) (@thick PkgKlassZ.Type) -> UInt16
+  // CHECK-DAG: sil package [serialized_for_package] [canonical] [ossa] @$s3Lib9PkgKlassZC4roots6UInt16VvgZ : $@convention(method) (@thick PkgKlassZ.Type) -> UInt16
   package static let root: UInt16 = 1 << 0
 
   // CHECK-DAG: sil shared [transparent] [serialized] [thunk] [canonical] [ossa] @$s3Lib9PkgKlassZCAA0B5ProtoA2aDP3envs6UInt16VvgTW : $@convention(witness_method: PkgProto) (@in_guaranteed PkgKlassZ) -> UInt16 {
@@ -396,7 +397,7 @@ package struct PkgStruct: PkgProto { /// NOTE: witness thunks get `shared` linka
   // CHECK-DAG: sil shared [transparent] [serialized] [thunk] [canonical] [ossa] @$s3Lib9PkgStructVAA0B5ProtoA2aDP4roots6UInt16VvgZTW : $@convention(witness_method: PkgProto) (@thick PkgStruct.Type) -> UInt16 {
   // CHECK-DAG: function_ref @$s3Lib9PkgStructV4roots6UInt16VvgZ : $@convention(method) (@thin PkgStruct.Type)
   // static PkgStruct.root.getter
-  // CHECK-DAG: sil package_external [canonical] @$s3Lib9PkgStructV4roots6UInt16VvgZ : $@convention(method) (@thin PkgStruct.Type) -> UInt16
+  // CHECK-DAG: sil package [serialized_for_package] [canonical] [ossa] @$s3Lib9PkgStructV4roots6UInt16VvgZ : $@convention(method) (@thin PkgStruct.Type) -> UInt16
   package static let root: UInt16 = 1 << 0
 
   // CHECK-DAG: sil shared [transparent] [serialized] [thunk] [canonical] [ossa] @$s3Lib9PkgStructVAA0B5ProtoA2aDP3envs6UInt16VvsTW : $@convention(witness_method: PkgProto) (UInt16, @inout PkgStruct) -> () {
diff --git a/test/SILOptimizer/performance-annotations.swift b/test/SILOptimizer/performance-annotations.swift
index e879f1e9ee996..28cd72fced322 100644
--- a/test/SILOptimizer/performance-annotations.swift
+++ b/test/SILOptimizer/performance-annotations.swift
@@ -485,7 +485,7 @@ func dynamicCastNoExistential(_ a: AnyObject) -> Cl? {
 
 @_noExistentials
 func useOfExistential() -> P {
-  Str(x: 1) // expected-error {{cannot use a value of protocol type 'any P' in @_noExistential function}}
+  Str(x: 1) // expected-error {{cannot use a value of protocol type 'any P' in '@_noExistential' function}}
 }
 
 @_noExistentials
diff --git a/test/SILOptimizer/performance_inliner.sil b/test/SILOptimizer/performance_inliner.sil
index 5b3af62713d91..2e3b46daa93ed 100644
--- a/test/SILOptimizer/performance_inliner.sil
+++ b/test/SILOptimizer/performance_inliner.sil
@@ -962,7 +962,7 @@ bb0(%1 : $@thick Self.Type):
   return %8 : $()
 }
 
-sil [always_inline] @has_self_metadata : $@convention(method) (@thick X.Type) -> @owned X {
+sil [heuristic_always_inline] @has_self_metadata : $@convention(method) (@thick X.Type) -> @owned X {
 bb0(%1 : $@thick X.Type):
   %3 = unchecked_trivial_bit_cast %1 : $@thick X.Type to $@thick @dynamic_self X.Type
   %27 = upcast %3 : $@thick @dynamic_self X.Type to $@thick X.Type
diff --git a/test/SILOptimizer/pre_specialize_layouts.swift b/test/SILOptimizer/pre_specialize_layouts.swift
index 66839d524e054..97c91b41f3b6b 100644
--- a/test/SILOptimizer/pre_specialize_layouts.swift
+++ b/test/SILOptimizer/pre_specialize_layouts.swift
@@ -1,22 +1,20 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutPrespecialization -emit-module-path %t/pre_specialized_module_layouts.swiftmodule %S/Inputs/pre_specialized_module_layouts.swift
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutPrespecialization -I %t -O -Xllvm -sil-disable-pass=function-signature-opts -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=OPT -check-prefix=OPT-%target-os
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutPrespecialization -I %t -Onone -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=NONE -check-prefix=NONE-%target-os
+// RUN: %target-swift-frontend -emit-module-path %t/pre_specialized_module_layouts.swiftmodule %S/Inputs/pre_specialized_module_layouts.swift
+// RUN: %target-swift-frontend -I %t -O -Xllvm -sil-disable-pass=function-signature-opts -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=OPT -check-prefix=OPT-%target-os
+// RUN: %target-swift-frontend -I %t -Onone -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=NONE -check-prefix=NONE-%target-os
 
 
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutPrespecialization -O -emit-module-path %t/pre_specialized_module_layouts.swiftmodule %S/Inputs/pre_specialized_module_layouts.swift
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutPrespecialization -I %t -O -Xllvm -sil-disable-pass=function-signature-opts -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=OPT
+// RUN: %target-swift-frontend -O -emit-module-path %t/pre_specialized_module_layouts.swiftmodule %S/Inputs/pre_specialized_module_layouts.swift
+// RUN: %target-swift-frontend -I %t -O -Xllvm -sil-disable-pass=function-signature-opts -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=OPT
 
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutPrespecialization -O -enable-library-evolution -emit-module-path %t/pre_specialized_module_layouts.swiftmodule %S/Inputs/pre_specialized_module_layouts.swift
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutPrespecialization -I %t -O -Xllvm -sil-disable-pass=function-signature-opts -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=OPT
+// RUN: %target-swift-frontend -O -enable-library-evolution -emit-module-path %t/pre_specialized_module_layouts.swiftmodule %S/Inputs/pre_specialized_module_layouts.swift
+// RUN: %target-swift-frontend -I %t -O -Xllvm -sil-disable-pass=function-signature-opts -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=OPT
 
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutPrespecialization -O -swift-version 5 -enable-library-evolution -emit-module -o /dev/null -emit-module-interface-path %t/pre_specialized_module_layouts.swiftinterface %S/Inputs/pre_specialized_module_layouts.swift -module-name pre_specialized_module_layouts
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutPrespecialization -I %t -O -Xllvm -sil-disable-pass=function-signature-opts -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=OPT
-
-// REQUIRES: swift_feature_LayoutPrespecialization
+// RUN: %target-swift-frontend -O -swift-version 5 -enable-library-evolution -emit-module -o /dev/null -emit-module-interface-path %t/pre_specialized_module_layouts.swiftinterface %S/Inputs/pre_specialized_module_layouts.swift -module-name pre_specialized_module_layouts
+// RUN: %target-swift-frontend -I %t -O -Xllvm -sil-disable-pass=function-signature-opts -Xllvm -sil-print-types -emit-sil %s | %FileCheck %s --check-prefix=OPT
 
 import pre_specialized_module_layouts
 
@@ -189,7 +187,6 @@ public func usePrespecializedEntryPoints(wrapperStruct: ReferenceWrapperStruct,
 // OPT:   [[A1:%.*]] = unchecked_ref_cast [[P1]] : $SomeClass to $AnyObject
 // OPT:   [[R3:%.*]] = apply [[F1]]([[A1]]) : $@convention(thin) (@guaranteed AnyObject) -> @owned AnyObject
 // OPT:   store [[R3]] to [[R2]] : $*AnyObject
-// OPT:   [[A2:%.*]] = load [[R1]] : $*SomeClass
 // OPT:   [[F2:%.*]] = function_ref @$s22pre_specialize_layouts7consumeyyxlF0a20_specialized_module_C09SomeClassC_Ttg5 : $@convention(thin) () -> ()
 // OPT:   apply [[F2]]() : $@convention(thin) () -> ()
 // OPT:   dealloc_stack [[R1]] : $*SomeClass
diff --git a/test/SILOptimizer/prespecialize_public.swift b/test/SILOptimizer/prespecialize_public.swift
new file mode 100644
index 0000000000000..2243dca0ee5ec
--- /dev/null
+++ b/test/SILOptimizer/prespecialize_public.swift
@@ -0,0 +1,30 @@
+// RUN: %target-swift-frontend  %s -O -emit-sil | %FileCheck %s
+
+// REQUIRES: optimized_stdlib
+
+extension Sequence where Element: BinaryInteger {
+
+  @specialized(where Self == [Int])
+  public func sum() -> Double {
+    reduce(0) { $0 + Double($1) }
+  }
+// CHECK: sil @$sST20prespecialize_publicSz7ElementRpzrlE3sumSdyF : $@convention(method) <Self where Self : Sequence, Self.Element : BinaryInteger> (@in_guaranteed Self) -> Double {
+// CHECK: bb0(%0 : $*Self):
+// CHECK:   [[T1:%.*]] = metatype $@thick Self.Type
+// CHECK:   [[T2:%.*]] = metatype $@thick Array<Int>.Type
+// CHECK:   [[T3:%.*]] = unchecked_trivial_bit_cast [[T1]] to $Builtin.Word
+// CHECK:   [[T4:%.*]] = unchecked_trivial_bit_cast [[T2]] to $Builtin.Word
+// CHECK:   [[T5:%.*]] = builtin "cmp_eq_Word"([[T3]], [[T4]]) : $Builtin.Int1
+// CHECK:   cond_br [[T5]], bb3, bb1
+
+// CHECK: bb1:
+// CHECK:   [[T6:%.*]] = function_ref @$sSTsE6reduceyqd__qd___qd__qd___7ElementQztKXEtKlF
+// CHECK:   apply {{.*}} [[T6]]<Self, Double>(
+// CHECK:   br bb2(
+
+// CHECK: bb2({{.*}} : $Double):
+// CHECK:   return
+
+// CHECK: bb3:
+// CHECK:   %25 = unchecked_addr_cast %0 to $*Array<Int>
+}
diff --git a/test/SILOptimizer/propagate_opaque_return_type.swift b/test/SILOptimizer/propagate_opaque_return_type.swift
index eac6119c86107..d152b27bb1595 100644
--- a/test/SILOptimizer/propagate_opaque_return_type.swift
+++ b/test/SILOptimizer/propagate_opaque_return_type.swift
@@ -2,6 +2,8 @@
 
 // REQUIRES: executable_test
 
+// UNSUPPORTED: back_deployment_runtime
+
 protocol P {}
 extension P {
   func foo() -> some Sequence<Int> {
diff --git a/test/SILOptimizer/range_unit.sil b/test/SILOptimizer/range_unit.sil
new file mode 100644
index 0000000000000..69067622a18cc
--- /dev/null
+++ b/test/SILOptimizer/range_unit.sil
@@ -0,0 +1,420 @@
+// RUN: %target-sil-opt -test-runner %s -o /dev/null 2>&1 | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+
+sil_stage canonical
+
+class C {}
+
+// CHECK-LABEL: testIdentity: range_overlaps_path
+// CHECK: Overlap kind: containsBegin
+sil [ossa] @testIdentity : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %range"
+  %range = begin_borrow %0
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsPath1: range_overlaps_path
+// CHECK: Overlap kind: containsPath
+sil [ossa] @testContainsPath1 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  %path = begin_borrow %0
+  end_borrow %path
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsPath2: range_overlaps_path
+// CHECK: Overlap kind: containsPath
+sil [ossa] @testContainsPath2 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  br bb1
+bb1:
+  %path = begin_borrow %0
+  end_borrow %path
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsPath3: range_overlaps_path
+// CHECK: Overlap kind: containsPath
+sil [ossa] @testContainsPath3 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  br bb1
+bb1:
+  %path = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %path
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsPath4: range_overlaps_path
+// CHECK: Overlap kind: containsPath
+sil [ossa] @testContainsPath4 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  br bb1
+bb1:
+  %path = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %path
+  br bb3
+bb3:
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsBegin1: range_overlaps_path
+// CHECK: Overlap kind: containsBegin
+sil [ossa] @testContainsBegin1 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  %path = begin_borrow %0
+  end_borrow %range
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsBegin2: range_overlaps_path
+// CHECK: Overlap kind: containsBegin
+sil [ossa] @testContainsBegin2 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  br bb1
+bb1:
+  %path = begin_borrow %0
+  end_borrow %range
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsBegin3: range_overlaps_path
+// CHECK: Overlap kind: containsBegin
+sil [ossa] @testContainsBegin3 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  br bb1
+bb1:
+  %path = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %range
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsBegin4: range_overlaps_path
+// CHECK: Overlap kind: containsBegin
+sil [ossa] @testContainsBegin4 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  br bb1
+bb1:
+  %path = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %range
+  br bb3
+bb3:
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsEnd1: range_overlaps_path
+// CHECK: Overlap kind: containsEnd
+sil [ossa] @testContainsEnd1 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  %range = begin_borrow %0
+  end_borrow %path
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsEnd2: range_overlaps_path
+// CHECK: Overlap kind: containsEnd
+sil [ossa] @testContainsEnd2 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  %range = begin_borrow %0
+  end_borrow %path
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsEnd3: range_overlaps_path
+// CHECK: Overlap kind: containsEnd
+sil [ossa] @testContainsEnd3 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  %range = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %path
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testContainsEnd4: range_overlaps_path
+// CHECK: Overlap kind: containsEnd
+sil [ossa] @testContainsEnd4 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  %range = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %path
+  br bb3
+bb3:
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testOverlappedByPath1: range_overlaps_path
+// CHECK: Overlap kind: overlappedByPath
+sil [ossa] @testOverlappedByPath1 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  %range = begin_borrow %0
+  end_borrow %range
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testOverlappedByPath2: range_overlaps_path
+// CHECK: Overlap kind: overlappedByPath
+sil [ossa] @testOverlappedByPath2 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  %range = begin_borrow %0
+  end_borrow %range
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testOverlappedByPath3: range_overlaps_path
+// CHECK: Overlap kind: overlappedByPath
+sil [ossa] @testOverlappedByPath3 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  %range = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %range
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testOverlappedByPath4: range_overlaps_path
+// CHECK: Overlap kind: overlappedByPath
+sil [ossa] @testOverlappedByPath4 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  %range = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %range
+  br bb3
+bb3:
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testOverlappedByPath5: range_overlaps_path
+// CHECK: Overlap kind: overlappedByPath
+sil [ossa] @testOverlappedByPath5 : $@convention(thin) (@owned C, @owned C) -> () {
+entry(%0 : @owned $C, %1 : @owned $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = move_value %0
+  %range = move_value %1
+  %tuple = tuple (%path, %range)
+  destroy_value %tuple
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testDisjoint1: range_overlaps_path
+// CHECK: Overlap kind: disjoint
+sil [ossa] @testDisjoint1 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  end_borrow %path
+  %range = begin_borrow %0
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testDisjoint2: range_overlaps_path
+// CHECK: Overlap kind: disjoint
+sil [ossa] @testDisjoint2 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  end_borrow %range
+  %path = begin_borrow %0
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testDisjoint3: range_overlaps_path
+// CHECK: Overlap kind: disjoint
+sil [ossa] @testDisjoint3 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  end_borrow %range
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testDisjoint4: range_overlaps_path
+// CHECK: Overlap kind: disjoint
+sil [ossa] @testDisjoint4 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  end_borrow %path
+  %range = begin_borrow %0
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testDisjoint5: range_overlaps_path
+// CHECK: Overlap kind: disjoint
+sil [ossa] @testDisjoint5 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = begin_borrow %0
+  br bb1
+bb1:
+  end_borrow %range
+  %path = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %path
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testDisjoint6: range_overlaps_path
+// CHECK: Overlap kind: disjoint
+sil [ossa] @testDisjoint6 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  end_borrow %path
+  %range = begin_borrow %0
+  br bb2
+bb2:
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testDisjoint7: range_overlaps_path
+// CHECK: Overlap kind: disjoint
+sil [ossa] @testDisjoint7 : $@convention(thin) (@guaranteed C) -> () {
+entry(%0 : @guaranteed $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = begin_borrow %0
+  br bb1
+bb1:
+  end_borrow %path
+  br bb2
+bb2:
+  %range = begin_borrow %0
+  br bb3
+bb3:
+  end_borrow %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testDisjoint8: range_overlaps_path
+// CHECK: Overlap kind: disjoint
+sil [ossa] @testDisjoint8 : $@convention(thin) (@owned C) -> () {
+entry(%0 : @owned $C):
+  specify_test "range_overlaps_path %range %path"
+  %path = move_value %0
+  %range = move_value %path
+  destroy_value %range
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: testDisjoint9: range_overlaps_path
+// CHECK: Overlap kind: disjoint
+sil [ossa] @testDisjoint9 : $@convention(thin) (@owned C) -> () {
+entry(%0 : @owned $C):
+  specify_test "range_overlaps_path %range %path"
+  %range = move_value %0
+  %path = move_value %range
+  destroy_value %path
+  %retval = tuple ()
+  return %retval : $()
+}
diff --git a/test/SILOptimizer/raw_sil_inst_lowering.sil b/test/SILOptimizer/raw_sil_inst_lowering.sil
index 04818feebabf2..4c249b88d13d5 100644
--- a/test/SILOptimizer/raw_sil_inst_lowering.sil
+++ b/test/SILOptimizer/raw_sil_inst_lowering.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -raw-sil-inst-lowering | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all -definite-init -raw-sil-inst-lowering %s | %FileCheck %s
 
 sil_stage raw
 
@@ -79,139 +79,303 @@ bb0(%0 : $*SomeClass, %1 : @owned $SomeClass):
 }
 
 @propertyWrapper struct Wrapper<T> {
-  @_hasStorage var wrappedValue: T
+  @_hasStorage var wrappedValue: T { get set }
   init(wrappedValue initialValue: T)
 }
 
 struct RefStruct {
-  @_hasStorage var _wrapped: Wrapper<SomeClass>
+  @_hasStorage var _wrapped: Wrapper<SomeClass> { get set }
+  var wrapped: SomeClass {
+    @storageRestrictions(initializes: _wrapped) init
+    get
+    set
+  }
+  init(inputVal: SomeClass)
 }
 
-
-sil @init_closure : $@convention(thin) (@owned SomeClass) -> @owned Wrapper<SomeClass>
-sil @init_closure_indirect : $@convention(thin) (@owned SomeClass) -> @out Wrapper<SomeClass>
-sil @set_closure : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-
-// CHECK-LABEL: sil [ossa] @assign_by_wrapper_initialization_direct
-// CHECK:   [[E:%[0-9]+]] = struct_element_addr
-// CHECK:   [[C:%[0-9]+]] = function_ref @init_closure
-// CHECK:   [[P:%[0-9]+]] = partial_apply [callee_guaranteed] [[C]]()
-// CHECK-NOT: partial_apply
-// CHECK:   [[R:%[0-9]+]] = apply [[P]](%0)
-// CHECK:   store [[R]] to [init] [[E]]
-// CHECK: } // end sil function 'assign_by_wrapper_initialization_direct'
-sil [ossa] @assign_by_wrapper_initialization_direct : $@convention(method) (@owned SomeClass) -> @owned RefStruct {
-bb0(%0 : @owned $SomeClass):
-  %1 = alloc_stack $RefStruct
-  %7 = struct_element_addr %1 : $*RefStruct, #RefStruct._wrapped
-  %8 = function_ref @init_closure : $@convention(thin) (@owned SomeClass) -> @owned Wrapper<SomeClass>
-  %9 = partial_apply [callee_guaranteed] %8() : $@convention(thin) (@owned SomeClass) -> @owned Wrapper<SomeClass>
-  %10 = function_ref @set_closure : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  %11 = partial_apply [callee_guaranteed] %10(%1) : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  assign_by_wrapper %0 : $SomeClass to [init] %7 : $*Wrapper<SomeClass>, init %9 : $@callee_guaranteed (@owned SomeClass) -> @owned Wrapper<SomeClass>, set %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %9 : $@callee_guaranteed (@owned SomeClass) -> @owned Wrapper<SomeClass>
-  %16 = load [take] %1 : $*RefStruct
-  dealloc_stack %1 : $*RefStruct
-  return %16 : $RefStruct
+// Wrapper.init(wrappedValue:)
+sil hidden [ossa] @$s4main7WrapperV12wrappedValueACyxGx_tcfC : $@convention(method) <T> (@in T, @thin Wrapper<T>.Type) -> @out Wrapper<T> {
+bb0(%0 : $*Wrapper<T>, %1 : $*T, %2 : $@thin Wrapper<T>.Type):
+  %3 = alloc_box $<τ_0_0> { var Wrapper<τ_0_0> } <T>, var, name "self" 
+  %4 = mark_uninitialized [rootself] %3 : $<τ_0_0> { var Wrapper<τ_0_0> } <T> 
+  %5 = begin_borrow [lexical] [var_decl] %4 : $<τ_0_0> { var Wrapper<τ_0_0> } <T> 
+  %6 = project_box %5 : $<τ_0_0> { var Wrapper<τ_0_0> } <T>, 0 
+  debug_value %1 : $*T, let, name "initialValue", argno 1, expr op_deref 
+  %8 = alloc_stack $T                             
+  copy_addr %1 to [init] %8 : $*T                 
+  %10 = begin_access [modify] [unknown] %6 : $*Wrapper<T> 
+  %11 = struct_element_addr %10 : $*Wrapper<T>, #Wrapper.wrappedValue 
+  copy_addr [take] %8 to %11 : $*T                
+  end_access %10 : $*Wrapper<T>                   
+  dealloc_stack %8 : $*T                          
+  copy_addr %6 to [init] %0 : $*Wrapper<T>        
+  destroy_addr %1 : $*T                           
+  end_borrow %5 : $<τ_0_0> { var Wrapper<τ_0_0> } <T> 
+  destroy_value %4 : $<τ_0_0> { var Wrapper<τ_0_0> } <T> 
+  %19 = tuple ()                                  
+  return %19 : $()                                
 }
 
-// CHECK-LABEL: sil [ossa] @assign_by_wrapper_initialization_indirect
-// CHECK:   [[E:%[0-9]+]] = struct_element_addr
-// CHECK:   [[C:%[0-9]+]] = function_ref @init_closure_indirect
-// CHECK:   [[P:%[0-9]+]] = partial_apply [callee_guaranteed] [[C]]()
-// CHECK-NOT: partial_apply
-// CHECK-NOT: destroy_addr
-// CHECK:   [[R:%[0-9]+]] = apply [[P]]([[E]], %0)
-// CHECK: } // end sil function 'assign_by_wrapper_initialization_indirect'
-sil [ossa] @assign_by_wrapper_initialization_indirect : $@convention(method) (@owned SomeClass) -> @owned RefStruct {
-bb0(%0 : @owned $SomeClass):
-  %1 = alloc_stack $RefStruct
-  %7 = struct_element_addr %1 : $*RefStruct, #RefStruct._wrapped
-  %8 = function_ref @init_closure_indirect : $@convention(thin) (@owned SomeClass) -> @out Wrapper<SomeClass>
-  %9 = partial_apply [callee_guaranteed] %8() : $@convention(thin) (@owned SomeClass) -> @out Wrapper<SomeClass>
-  %10 = function_ref @set_closure : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  %11 = partial_apply [callee_guaranteed] %10(%1) : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  assign_by_wrapper %0 : $SomeClass to [init] %7 : $*Wrapper<SomeClass>, init %9 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>, set %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %9 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>
-  %16 = load [take] %1 : $*RefStruct
-  dealloc_stack %1 : $*RefStruct
-  return %16 : $RefStruct
+// property wrapped field init accessor of RefStruct.wrapped
+sil hidden [ossa] @$s4main9RefStructV7wrappedAA9SomeClassCvpfF : $@convention(thin) (@owned SomeClass, @thin RefStruct.Type) -> @out Wrapper<SomeClass> {
+bb0(%0 : $*Wrapper<SomeClass>, %1 : @owned $SomeClass, %2 : $@thin RefStruct.Type):
+  %3 = mark_uninitialized [out] %0 : $*Wrapper<SomeClass> 
+  debug_value %1 : $SomeClass, let, name "$input_value", argno 1 
+  %5 = metatype $@thin Wrapper<SomeClass>.Type    
+  %6 = copy_value %1 : $SomeClass                 
+  %7 = alloc_stack $SomeClass                     
+  store %6 to [init] %7 : $*SomeClass             
+  %9 = function_ref @$s4main7WrapperV12wrappedValueACyxGx_tcfC : $@convention(method) <τ_0_0> (@in τ_0_0, @thin Wrapper<τ_0_0>.Type) -> @out Wrapper<τ_0_0> // user: %10
+  %10 = apply %9<SomeClass>(%3, %7, %5) : $@convention(method) <τ_0_0> (@in τ_0_0, @thin Wrapper<τ_0_0>.Type) -> @out Wrapper<τ_0_0>
+  dealloc_stack %7 : $*SomeClass                  
+  destroy_value %1 : $SomeClass                   
+  %13 = tuple ()                                  
+  return %13 : $()                                
+} 
+
+// RefStruct.wrapped.setter
+sil hidden [ossa] @$s4main9RefStructV7wrappedAA9SomeClassCvs : $@convention(method) (@owned SomeClass, @inout RefStruct) -> () {
+bb0(%0 : @owned $SomeClass, %1 : $*RefStruct):
+  debug_value %0 : $SomeClass, let, name "value", argno 1 
+  debug_value %1 : $*RefStruct, var, name "self", argno 2, expr op_deref
+  %4 = begin_borrow %0 : $SomeClass               
+  %5 = copy_value %4 : $SomeClass                 
+  %6 = begin_access [modify] [unknown] %1 : $*RefStruct
+  %7 = struct_element_addr %6 : $*RefStruct, #RefStruct._wrapped
+  %8 = struct_element_addr %7 : $*Wrapper<SomeClass>, #Wrapper.wrappedValue
+  assign %5 to %8 : $*SomeClass                   
+  end_access %6 : $*RefStruct                     
+  end_borrow %4 : $SomeClass                      
+  destroy_value %0 : $SomeClass                   
+  %13 = tuple ()                                  
+  return %13 : $()                                
+} 
+
+// property wrapped field init accessor of GenericRefStruct.wrapped
+// Isolation: unspecified
+sil hidden [ossa] @$s4main16GenericRefStructV7wrappedxvpfF : $@convention(thin) <T> (@in T, @thin GenericRefStruct<T>.Type) -> @out Wrapper<T> {
+bb0(%0 : $*Wrapper<T>, %1 : $*T, %2 : $@thin GenericRefStruct<T>.Type):
+  %3 = mark_uninitialized [out] %0 : $*Wrapper<T> // user: %9
+  debug_value %1 : $*T, let, name "$input_value", argno 1, expr op_deref // id: %4
+  %5 = metatype $@thin Wrapper<T>.Type            // user: %9
+  %6 = alloc_stack $T                             // users: %10, %9, %7
+  copy_addr %1 to [init] %6 : $*T                 // id: %7
+  // function_ref Wrapper.init(wrappedValue:)
+  %8 = function_ref @$s4main7WrapperV12wrappedValueACyxGx_tcfC : $@convention(method) <τ_0_0> (@in τ_0_0, @thin Wrapper<τ_0_0>.Type) -> @out Wrapper<τ_0_0> // user: %9
+  %9 = apply %8<T>(%3, %6, %5) : $@convention(method) <τ_0_0> (@in τ_0_0, @thin Wrapper<τ_0_0>.Type) -> @out Wrapper<τ_0_0>
+  dealloc_stack %6 : $*T                          // id: %10
+  destroy_addr %1 : $*T                           // id: %11
+  %12 = tuple ()                                  // user: %13
+  return %12 : $()                                // id: %13
+} // end sil function '$s4main16GenericRefStructV7wrappedxvpfF'
+
+// GenericRefStruct.wrapped.setter
+// Isolation: unspecified
+sil hidden [ossa] @$s4main16GenericRefStructV7wrappedxvs : $@convention(method) <T> (@in T, @inout GenericRefStruct<T>) -> () {
+// %0 "value"                                     // users: %12, %5, %2
+// %1 "self"                                      // users: %6, %3
+bb0(%0 : $*T, %1 : $*GenericRefStruct<T>):
+  debug_value %0 : $*T, let, name "value", argno 1, expr op_deref // id: %2
+  debug_value %1 : $*GenericRefStruct<T>, var, name "self", argno 2, expr op_deref // id: %3
+  %4 = alloc_stack $T                             // users: %11, %9, %5
+  copy_addr %0 to [init] %4 : $*T                 // id: %5
+  %6 = begin_access [modify] [unknown] %1 : $*GenericRefStruct<T> // users: %10, %7
+  %7 = struct_element_addr %6 : $*GenericRefStruct<T>, #GenericRefStruct._wrapped // user: %8
+  %8 = struct_element_addr %7 : $*Wrapper<T>, #Wrapper.wrappedValue // user: %9
+  copy_addr [take] %4 to %8 : $*T                 // id: %9
+  end_access %6 : $*GenericRefStruct<T>           // id: %10
+  dealloc_stack %4 : $*T                          // id: %11
+  destroy_addr %0 : $*T                           // id: %12
+  %13 = tuple ()                                  // user: %14
+  return %13 : $()                                // id: %14
 }
 
-// CHECK-LABEL: sil [ossa] @assign_by_wrapper_assign_direct
-// CHECK:   [[E:%[0-9]+]] = struct_element_addr
-// CHECK:   [[C:%[0-9]+]] = function_ref @init_closure
-// CHECK:   [[P:%[0-9]+]] = partial_apply [callee_guaranteed] [[C]]()
-// CHECK-NOT: partial_apply
-// CHECK:   [[R:%[0-9]+]] = apply [[P]](%0)
-// CHECK:   store [[R]] to [assign] [[E]]
-// CHECK: } // end sil function 'assign_by_wrapper_assign_direct'
-sil [ossa] @assign_by_wrapper_assign_direct : $@convention(method) (@owned SomeClass, @owned Wrapper<SomeClass>) -> @owned RefStruct {
-bb0(%0 : @owned $SomeClass, %1 : @owned $Wrapper<SomeClass>):
-  %2 = alloc_stack $RefStruct
-  %7 = struct_element_addr %2 : $*RefStruct, #RefStruct._wrapped
-  store %1 to [init] %7 : $*Wrapper<SomeClass>
-  %8 = function_ref @init_closure : $@convention(thin) (@owned SomeClass) -> @owned Wrapper<SomeClass>
-  %9 = partial_apply [callee_guaranteed] %8() : $@convention(thin) (@owned SomeClass) -> @owned Wrapper<SomeClass>
-  %10 = function_ref @set_closure : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  %11 = partial_apply [callee_guaranteed] %10(%2) : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  assign_by_wrapper %0 : $SomeClass to [assign] %7 : $*Wrapper<SomeClass>, init %9 : $@callee_guaranteed (@owned SomeClass) -> @owned Wrapper<SomeClass>, set %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %9 : $@callee_guaranteed (@owned SomeClass) -> @owned Wrapper<SomeClass>
-  %16 = load [take] %2 : $*RefStruct
-  dealloc_stack %2 : $*RefStruct
-  return %16 : $RefStruct
+// ====== CASE 01 - Init Indirect =========
+// [Init] mode chosen because backing storage ._wrapped is uninitialized
+// The initializer closure (an init accessor thunk) has an indirect return type
+// Therefore, ._wrapped gets initialized indirectly
+
+// RefStruct.init(inputVal:)
+// CHECK-LABEL: sil hidden [ossa] @$assign_or_init_init_indirect
+// CHECK: [[INITIAL_VAL:%.*]] = copy_value {{%.*}} : $SomeClass 
+// CHECK: [[SELF_REF:%.*]] = begin_access [modify] [unknown] {{%.*}} : $*RefStruct
+// CHECK: [[INIT_REF:%.*]] = function_ref @$s4main9RefStructV7wrappedAA9SomeClassCvpfF : $@convention(thin) (@owned SomeClass, @thin RefStruct.Type) -> @out Wrapper<SomeClass>
+// CHECK: [[INIT_PAI:%.*]] = partial_apply [callee_guaranteed] [[INIT_REF]]({{%.*}})
+// CHECK: [[FIELD_REF:%.*]] = struct_element_addr [[SELF_REF]] : $*RefStruct, #RefStruct._wrapped
+// CHECK-NEXT: {{%.*}} = apply [[INIT_PAI]]([[FIELD_REF]], [[INITIAL_VAL]]) : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>
+sil hidden [ossa] @$assign_or_init_init_indirect : $@convention(method) (@owned SomeClass, @thin RefStruct.Type) -> @owned RefStruct {
+bb0(%0 : @owned $SomeClass, %1 : $@thin RefStruct.Type):
+  %2 = alloc_box ${ var RefStruct }, var, name "self" 
+  %3 = mark_uninitialized [rootself] %2 : ${ var RefStruct } 
+  %4 = begin_borrow [lexical] [var_decl] %3 : ${ var RefStruct } 
+  %5 = project_box %4 : ${ var RefStruct }, 0     
+  debug_value %0 : $SomeClass, let, name "inputVal", argno 1 
+  %7 = begin_borrow %0 : $SomeClass               
+  %8 = copy_value %7 : $SomeClass                 
+  %9 = begin_access [modify] [unknown] %5 : $*RefStruct 
+  %10 = function_ref @$s4main9RefStructV7wrappedAA9SomeClassCvpfF : $@convention(thin) (@owned SomeClass, @thin RefStruct.Type) -> @out Wrapper<SomeClass> // user: %12
+  %11 = metatype $@thin RefStruct.Type            
+  %12 = partial_apply [callee_guaranteed] %10(%11) : $@convention(thin) (@owned SomeClass, @thin RefStruct.Type) -> @out Wrapper<SomeClass> // users: %18, %15
+  %13 = function_ref @$s4main9RefStructV7wrappedAA9SomeClassCvs : $@convention(method) (@owned SomeClass, @inout RefStruct) -> () // user: %14
+  %14 = partial_apply [callee_guaranteed] [on_stack] %13(%9) : $@convention(method) (@owned SomeClass, @inout RefStruct) -> () // users: %17, %15
+  assign_or_init #RefStruct.wrapped, 
+                 self %9 : $*RefStruct, 
+                 value %8 : $SomeClass, 
+                 init %12 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>, 
+                 set %14 : $@noescape @callee_guaranteed (@owned SomeClass) -> () // id: %15
+  end_access %9 : $*RefStruct                     
+  destroy_value %14 : $@noescape @callee_guaranteed (@owned SomeClass) -> () 
+  destroy_value %12 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>
+  end_borrow %7 : $SomeClass                      
+  %20 = load [copy] %5 : $*RefStruct              
+  destroy_value %0 : $SomeClass                   
+  end_borrow %4 : ${ var RefStruct }              
+  destroy_value %3 : ${ var RefStruct }           
+  return %20 : $RefStruct                         
 }
 
-// CHECK-LABEL: sil [ossa] @assign_by_wrapper_assign_indirect
-// CHECK:   [[E:%[0-9]+]] = struct_element_addr
-// CHECK:   [[C:%[0-9]+]] = function_ref @init_closure_indirect
-// CHECK:   [[P:%[0-9]+]] = partial_apply [callee_guaranteed] [[C]]()
-// CHECK-NOT: partial_apply
-// CHECK:   destroy_addr [[E]]
-// CHECK:   [[R:%[0-9]+]] = apply [[P]]([[E]], %0)
-// CHECK: } // end sil function 'assign_by_wrapper_assign_indirect'
-sil [ossa] @assign_by_wrapper_assign_indirect : $@convention(method) (@owned SomeClass, @owned Wrapper<SomeClass>) -> @owned RefStruct {
-bb0(%0 : @owned $SomeClass, %1 : @owned $Wrapper<SomeClass>):
-  %2 = alloc_stack $RefStruct
-  %7 = struct_element_addr %2 : $*RefStruct, #RefStruct._wrapped
-  store %1 to [init] %7 : $*Wrapper<SomeClass>
-  %8 = function_ref @init_closure_indirect : $@convention(thin) (@owned SomeClass) -> @out Wrapper<SomeClass>
-  %9 = partial_apply [callee_guaranteed] %8() : $@convention(thin) (@owned SomeClass) -> @out Wrapper<SomeClass>
-  %10 = function_ref @set_closure : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  %11 = partial_apply [callee_guaranteed] %10(%2) : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  assign_by_wrapper %0 : $SomeClass to [assign] %7 : $*Wrapper<SomeClass>, init %9 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>, set %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %9 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>
-  %16 = load [take] %2 : $*RefStruct
-  dealloc_stack %2 : $*RefStruct
-  return %16 : $RefStruct
+// ====== CASE 02 - Assign Direct ============ 
+// RefStruct is already initialized, so DI selects [assign] mode
+// Because the property type (SomeClass) is loadable, the setter can consume the value directly
+// This test verifies that the setter path is taken
+
+// RefStruct.init(inputVal:)
+// CHECK-LABEL: sil hidden [ossa] @$assign_or_init_assign_direct
+// CHECK: [[FIELD_REF:%.*]] = struct_element_addr {{.*}} : $*RefStruct, #RefStruct._wrapped
+// CHECK-NEXT: {{.*}} = apply [[INIT_PAI]]([[FIELD_REF]], [[INITIAL_VAL]]) : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>
+// CHECK: [[INITIAL_VAL2:%.*]] = copy_value {{%.*}} : $SomeClass
+// CHECK: [[SELF_REF:%.*]] = begin_access [modify] [unknown] {{%.*}} : $*RefStruct
+// CHECK: [[SETTER_REF:%.*]] = function_ref @$s4main9RefStructV7wrappedAA9SomeClassCvs : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
+// CHECK-NEXT: [[SETTER_PAI:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[SETTER_REF]]([[SELF_REF]]) : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
+// CHECK-NEXT: {{.*}} = apply [[SETTER_PAI]]([[INITIAL_VAL2]]) : $@noescape @callee_guaranteed (@owned SomeClass) -> () 
+sil hidden [ossa] @$assign_or_init_assign_direct : $@convention(method) (@owned SomeClass, @thin RefStruct.Type) -> @owned RefStruct {
+bb0(%0 : @owned $SomeClass, %1 : $@thin RefStruct.Type):
+  %2 = alloc_box ${ var RefStruct }, var, name "self" // user: %3
+  %3 = mark_uninitialized [rootself] %2 : ${ var RefStruct } // users: %36, %4
+  %4 = begin_borrow [lexical] [var_decl] %3 : ${ var RefStruct } // users: %35, %5
+  %5 = project_box %4 : ${ var RefStruct }, 0     // users: %33, %22, %9
+  debug_value %0 : $SomeClass, let, name "inputVal", argno 1 // id: %6
+  %7 = begin_borrow %0 : $SomeClass               // users: %19, %8
+  %8 = copy_value %7 : $SomeClass                 // user: %15
+  %9 = begin_access [modify] [unknown] %5 : $*RefStruct // users: %16, %15, %14
+  
+  // Initialization
+  %10 = function_ref @$s4main9RefStructV7wrappedAA9SomeClassCvpfF : $@convention(thin) (@owned SomeClass, @thin RefStruct.Type) -> @out Wrapper<SomeClass> // user: %12
+  %11 = metatype $@thin RefStruct.Type            // user: %12
+  %12 = partial_apply [callee_guaranteed] %10(%11) : $@convention(thin) (@owned SomeClass, @thin RefStruct.Type) -> @out Wrapper<SomeClass> // users: %18, %15
+  %13 = function_ref @$s4main9RefStructV7wrappedAA9SomeClassCvs : $@convention(method) (@owned SomeClass, @inout RefStruct) -> () // user: %14
+  %14 = partial_apply [callee_guaranteed] [on_stack] %13(%9) : $@convention(method) (@owned SomeClass, @inout RefStruct) -> () // users: %17, %15
+  assign_or_init #RefStruct.wrapped, 
+                 self %9 : $*RefStruct, 
+                 value %8 : $SomeClass, 
+                 init %12 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>, 
+                 set %14 : $@noescape @callee_guaranteed (@owned SomeClass) -> () // id: %15
+  end_access %9 : $*RefStruct                     // id: %16
+  destroy_value %14 : $@noescape @callee_guaranteed (@owned SomeClass) -> () // id: %17
+  destroy_value %12 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass> // id: %18
+  end_borrow %7 : $SomeClass                      // id: %19
+  %20 = begin_borrow %0 : $SomeClass              // users: %32, %21
+  %21 = copy_value %20 : $SomeClass               // user: %28
+  %22 = begin_access [modify] [unknown] %5 : $*RefStruct // users: %29, %28, %27
+  
+  // Assignment
+  %23 = function_ref @$s4main9RefStructV7wrappedAA9SomeClassCvpfF : $@convention(thin) (@owned SomeClass, @thin RefStruct.Type) -> @out Wrapper<SomeClass> // user: %25
+  %24 = metatype $@thin RefStruct.Type            // user: %25
+  %25 = partial_apply [callee_guaranteed] %23(%24) : $@convention(thin) (@owned SomeClass, @thin RefStruct.Type) -> @out Wrapper<SomeClass> // users: %31, %28
+  %26 = function_ref @$s4main9RefStructV7wrappedAA9SomeClassCvs : $@convention(method) (@owned SomeClass, @inout RefStruct) -> () // user: %27
+  %27 = partial_apply [callee_guaranteed] [on_stack] %26(%22) : $@convention(method) (@owned SomeClass, @inout RefStruct) -> () // users: %30, %28
+  assign_or_init #RefStruct.wrapped, 
+                 self %22 : $*RefStruct, 
+                 value %21 : $SomeClass, 
+                 init %25 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass>, 
+                 set %27 : $@noescape @callee_guaranteed (@owned SomeClass) -> ()
+  end_access %22 : $*RefStruct                    // id: %29
+  destroy_value %27 : $@noescape @callee_guaranteed (@owned SomeClass) -> () 
+  destroy_value %25 : $@callee_guaranteed (@owned SomeClass) -> @out Wrapper<SomeClass> 
+  end_borrow %20 : $SomeClass                     
+  %33 = load [copy] %5 : $*RefStruct              
+  destroy_value %0 : $SomeClass                   
+  end_borrow %4 : ${ var RefStruct }              
+  destroy_value %3 : ${ var RefStruct }           
+  return %33 : $RefStruct                         
 }
 
-// CHECK-LABEL: sil [ossa] @assign_by_wrapper_assign_wrapped_value
-// CHECK:   [[A:%[0-9]+]] = alloc_stack $RefStruct
-// CHECK:   [[E:%[0-9]+]] = struct_element_addr
-// CHECK-NOT: partial_apply
-// CHECK:   [[C:%[0-9]+]] = function_ref @set_closure
-// CHECK:   [[P:%[0-9]+]] = partial_apply [callee_guaranteed] [[C]]([[A]])
-// CHECK:   apply [[P]](%0)
-// CHECK: } // end sil function 'assign_by_wrapper_assign_wrapped_value'
-sil [ossa] @assign_by_wrapper_assign_wrapped_value : $@convention(method) (@owned SomeClass, @owned RefStruct) -> @owned RefStruct {
-bb0(%0 : @owned $SomeClass, %1 : @owned $RefStruct):
-  %2 = alloc_stack $RefStruct
-  store %1 to [init] %2 : $*RefStruct
-  %7 = struct_element_addr %2 : $*RefStruct, #RefStruct._wrapped
-  %8 = function_ref @init_closure : $@convention(thin) (@owned SomeClass) -> @owned Wrapper<SomeClass>
-  %9 = partial_apply [callee_guaranteed] %8() : $@convention(thin) (@owned SomeClass) -> @owned Wrapper<SomeClass>
-  %10 = function_ref @set_closure : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  %11 = partial_apply [callee_guaranteed] %10(%2) : $@convention(method) (@owned SomeClass, @inout RefStruct) -> ()
-  assign_by_wrapper %0 : $SomeClass to [assign_wrapped_value] %7 : $*Wrapper<SomeClass>, init %9 : $@callee_guaranteed (@owned SomeClass) -> @owned Wrapper<SomeClass>, set %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %11 : $@callee_guaranteed (@owned SomeClass) -> ()
-  destroy_value %9 : $@callee_guaranteed (@owned SomeClass) -> @owned Wrapper<SomeClass>
-  %16 = load [take] %2 : $*RefStruct
-  dealloc_stack %2 : $*RefStruct
-  return %16 : $RefStruct
+// ====== CASE 03 - Assign Indirect ==========
+// RefStruct is already initialized, so DI selects [assign] mode
+// The wrapped property type is address-only (e.g. a generic T), so values
+// are passed indirectly instead of by value
+// This test verifies that the setter uses the indirect assignment path
+
+struct GenericRefStruct<T> {
+  @_hasStorage var _wrapped: Wrapper<T> { get set }
+  var wrapped: T {
+    @storageRestrictions(initializes: _wrapped) init
+    get
+    set
+  }
+  init(inputVal: T)
 }
 
+// GenericRefStruct.init(inputVal:)
+// CHECK-LABEL: sil hidden [ossa] @$assign_or_init_assign_indirect
+// CHECK: [[TADDR1:%.*]] = alloc_stack $T
+// CHECK: copy_addr {{%.*}} to [init] [[TADDR1]] : $*T
+// CHECK: [[INIT_REF:%.*]] = function_ref @$s4main16GenericRefStructV7wrappedxvpfF : $@convention(thin) <{{.*}}> (@in {{.*}}, @thin GenericRefStruct<{{.*}}>.Type) -> @out Wrapper<{{.*}}>
+// CHECK: [[META1:%.*]] = metatype $@thin GenericRefStruct<{{.*}}>.Type
+// CHECK: [[INIT_PAI:%.*]] = partial_apply [callee_guaranteed] [[INIT_REF]]<{{.*}}>([[META1]])
+// CHECK: {{%.*}} = struct_element_addr %{{.*}} : $*GenericRefStruct<{{.*}}>, #GenericRefStruct._wrapped
+// CHECK-NEXT: {{%.*}} = apply [[INIT_PAI]](%{{.*}}, [[TADDR1]]) : $@callee_guaranteed (@in {{.*}}) -> @out Wrapper<{{.*}}>
+// CHECK: [[TADDR2:%.*]] = alloc_stack $T
+// CHECK: copy_addr {{%.*}} to [init] [[TADDR2]] : $*T
+// CHECK: [[SELF2:%.*]] = begin_access [modify] {{\[.*\]}} %{{.*}} : $*GenericRefStruct<{{.*}}>
+// CHECK: [[SET_REF:%.*]] = function_ref @$s4main16GenericRefStructV7wrappedxvs : $@convention(method) <{{.*}}> (@in {{.*}}, @inout GenericRefStruct<{{.*}}>) -> ()
+// CHECK: [[SET_PAI:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[SET_REF]]<{{.*}}>([[SELF2]])
+// CHECK-NEXT: {{%.*}} = apply [[SET_PAI]]([[TADDR2]]) : $@noescape @callee_guaranteed (@in {{.*}}) -> ()
+sil hidden [ossa] @$assign_or_init_assign_indirect : $@convention(method) <T> (@in T, @thin GenericRefStruct<T>.Type) -> @out GenericRefStruct<T> {
+bb0(%0 : $*GenericRefStruct<T>, %1 : $*T, %2 : $@thin GenericRefStruct<T>.Type):
+  %3 = alloc_box $<τ_0_0> { var GenericRefStruct<τ_0_0> } <T>, var, name "self" // user: %4
+  %4 = mark_uninitialized [rootself] %3 : $<τ_0_0> { var GenericRefStruct<τ_0_0> } <T> // users: %37, %5
+  %5 = begin_borrow [lexical] [var_decl] %4 : $<τ_0_0> { var GenericRefStruct<τ_0_0> } <T> // users: %36, %6
+  %6 = project_box %5 : $<τ_0_0> { var GenericRefStruct<τ_0_0> } <T>, 0 // users: %34, %23, %10
+  debug_value %1 : $*T, let, name "inputVal", argno 1, expr op_deref // id: %7
+  %8 = alloc_stack $T                             // users: %20, %16, %9
+  copy_addr %1 to [init] %8 : $*T                 // id: %9
+  %10 = begin_access [modify] [unknown] %6 : $*GenericRefStruct<T> // users: %17, %16, %15
+  
+  // Initialization
+  %11 = function_ref @$s4main16GenericRefStructV7wrappedxvpfF : $@convention(thin) <τ_0_0> (@in τ_0_0, @thin GenericRefStruct<τ_0_0>.Type) -> @out Wrapper<τ_0_0> // user: %13
+  %12 = metatype $@thin GenericRefStruct<T>.Type  // user: %13
+  %13 = partial_apply [callee_guaranteed] %11<T>(%12) : $@convention(thin) <τ_0_0> (@in τ_0_0, @thin GenericRefStruct<τ_0_0>.Type) -> @out Wrapper<τ_0_0> // users: %19, %16
+  %14 = function_ref @$s4main16GenericRefStructV7wrappedxvs : $@convention(method) <τ_0_0> (@in τ_0_0, @inout GenericRefStruct<τ_0_0>) -> () // user: %15
+  %15 = partial_apply [callee_guaranteed] [on_stack] %14<T>(%10) : $@convention(method) <τ_0_0> (@in τ_0_0, @inout GenericRefStruct<τ_0_0>) -> () // users: %18, %16
+  assign_or_init #GenericRefStruct.wrapped, 
+                 self %10 : $*GenericRefStruct<T>, 
+                 value %8 : $*T, 
+                 init %13 : $@callee_guaranteed (@in T) -> @out Wrapper<T>, 
+                 set %15 : $@noescape @callee_guaranteed (@in T) -> ()
+  end_access %10 : $*GenericRefStruct<T>          // id: %17
+  destroy_value %15 : $@noescape @callee_guaranteed (@in T) -> () // id: %18
+  destroy_value %13 : $@callee_guaranteed (@in T) -> @out Wrapper<T> // id: %19
+  dealloc_stack %8 : $*T                          // id: %20
+  %21 = alloc_stack $T                            // users: %33, %29, %22
+  copy_addr %1 to [init] %21 : $*T                // id: %22
+  %23 = begin_access [modify] [unknown] %6 : $*GenericRefStruct<T> // users: %30, %29, %28
+  
+  // Assignment
+  %24 = function_ref @$s4main16GenericRefStructV7wrappedxvpfF : $@convention(thin) <τ_0_0> (@in τ_0_0, @thin GenericRefStruct<τ_0_0>.Type) -> @out Wrapper<τ_0_0> // user: %26
+  %25 = metatype $@thin GenericRefStruct<T>.Type  // user: %26
+  %26 = partial_apply [callee_guaranteed] %24<T>(%25) : $@convention(thin) <τ_0_0> (@in τ_0_0, @thin GenericRefStruct<τ_0_0>.Type) -> @out Wrapper<τ_0_0> // users: %32, %29
+  %27 = function_ref @$s4main16GenericRefStructV7wrappedxvs : $@convention(method) <τ_0_0> (@in τ_0_0, @inout GenericRefStruct<τ_0_0>) -> () // user: %28
+  %28 = partial_apply [callee_guaranteed] [on_stack] %27<T>(%23) : $@convention(method) <τ_0_0> (@in τ_0_0, @inout GenericRefStruct<τ_0_0>) -> () // users: %31, %29
+  assign_or_init #GenericRefStruct.wrapped, self %23 : $*GenericRefStruct<T>, value %21 : $*T, init %26 : $@callee_guaranteed (@in T) -> @out Wrapper<T>, set %28 : $@noescape @callee_guaranteed (@in T) -> () // id: %29
+  end_access %23 : $*GenericRefStruct<T>          // id: %30
+  destroy_value %28 : $@noescape @callee_guaranteed (@in T) -> () // id: %31
+  destroy_value %26 : $@callee_guaranteed (@in T) -> @out Wrapper<T> // id: %32
+  dealloc_stack %21 : $*T                         // id: %33
+  copy_addr %6 to [init] %0 : $*GenericRefStruct<T> // id: %34
+  destroy_addr %1 : $*T                           // id: %35
+  end_borrow %5 : $<τ_0_0> { var GenericRefStruct<τ_0_0> } <T> // id: %36
+  destroy_value %4 : $<τ_0_0> { var GenericRefStruct<τ_0_0> } <T> // id: %37
+  %38 = tuple ()                                  // user: %39
+  return %38 : $()                                // id: %39
+}
diff --git a/test/SILOptimizer/rcidentity_opaque.sil b/test/SILOptimizer/rcidentity_opaque.sil
index 9763b6055ef6f..ec53f9f23597e 100644
--- a/test/SILOptimizer/rcidentity_opaque.sil
+++ b/test/SILOptimizer/rcidentity_opaque.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -rc-id-dumper -enable-sil-opaque-values -module-name Swift %s -o /dev/null | %FileCheck %s
+// RUN: %target-sil-opt -rc-id-dumper -enable-sil-opaque-values -disable-objc-interop -module-name Swift %s -o /dev/null | %FileCheck %s
 
 import Builtin
 
@@ -295,7 +295,7 @@ bb0(%0 : @owned $T):
 //
 // CHECK-LABEL: @testClassToClassArchetypeIsBridged
 // CHECK: RESULT #0: 0 = 0
-// CHECK: RESULT #1: 1 = 1
+// CHECK: RESULT #1: 1 = 0
 sil [ossa] @testClassToClassArchetypeIsBridged : $@convention(thin) <U : AnyObject>(@owned Base) -> @owned U {
 bb0(%0 : @owned $Base):
   %1 = unconditional_checked_cast %0 : $Base to U
diff --git a/test/SILOptimizer/redundant_load_elim.sil b/test/SILOptimizer/redundant_load_elim.sil
index df3b635ea51a4..2f5b96a9321bc 100644
--- a/test/SILOptimizer/redundant_load_elim.sil
+++ b/test/SILOptimizer/redundant_load_elim.sil
@@ -1386,3 +1386,45 @@ bb0(%0 : $*B, %1 : $*B):
   return %3
 }
 
+// CHECK-LABEL: sil @copyaddr_after_store :
+// CHECK:         [[S:%.*]] = alloc_stack $B
+// CHECK:         store %1 to [[S]]
+// CHECK:         store %1 to %0
+// CHECK-LABEL: } // end sil function 'copyaddr_after_store'
+sil @copyaddr_after_store : $@convention(thin) (@owned B) -> @out B {
+bb0(%0 : $*B, %1 : $B):
+  %2 = alloc_stack $B
+  store %1 to %2
+  copy_addr [take] %2 to [init] %0
+  dealloc_stack %2
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil @dont_remove_copying_copyaddr :
+// CHECK:         copy_addr
+// CHECK-LABEL: } // end sil function 'dont_remove_copying_copyaddr'
+sil @dont_remove_copying_copyaddr : $@convention(thin) (@owned B) -> @out B {
+bb0(%0 : $*B, %1 : $B):
+  %2 = alloc_stack $B
+  store %1 to %2
+  copy_addr %2 to [init] %0
+  destroy_addr %2
+  dealloc_stack %2
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil @dont_remove_assigning_copyaddr :
+// CHECK:         copy_addr
+// CHECK-LABEL: } // end sil function 'dont_remove_assigning_copyaddr'
+sil @dont_remove_assigning_copyaddr : $@convention(thin) (@inout B, @owned B) -> () {
+bb0(%0 : $*B, %1 : $B):
+  %2 = alloc_stack $B
+  store %1 to %2
+  copy_addr [take] %2 to %0
+  dealloc_stack %2
+  %r = tuple ()
+  return %r
+}
+
diff --git a/test/SILOptimizer/redundant_load_elim_nontrivial_ossa.sil b/test/SILOptimizer/redundant_load_elim_nontrivial_ossa.sil
index da46259fadd93..4d3de14be08b5 100644
--- a/test/SILOptimizer/redundant_load_elim_nontrivial_ossa.sil
+++ b/test/SILOptimizer/redundant_load_elim_nontrivial_ossa.sil
@@ -1233,7 +1233,7 @@ bb0(%0 : $*MyArray<MyStruct>):
 
 // CHECK-LABEL: @load_trivial_from_store :
 // CHECK:         [[B:%.*]] = begin_borrow %0
-// CHECK:         [[I:%.*]] = struct_extract %2 : $Agg3, #Agg3.i
+// CHECK:         [[I:%.*]] = struct_extract [[B]] : $Agg3, #Agg3.i
 // CHECK:         end_borrow [[B]]
 // CHECK:         store %0 to [assign] %1
 // CHECK:         return [[I]]
@@ -1248,7 +1248,7 @@ bb0(%0 : @owned $Agg3, %1 : $*Agg3):
 
 // CHECK-LABEL: @load_copy_from_store :
 // CHECK:         [[B:%.*]] = begin_borrow %0
-// CHECK:         [[K:%.*]] = struct_extract %2 : $Agg3, #Agg3.k
+// CHECK:         [[K:%.*]] = struct_extract [[B]] : $Agg3, #Agg3.k
 // CHECK:         [[C:%.*]] = copy_value [[K]]
 // CHECK:         end_borrow [[B]]
 // CHECK:         store %0 to [assign] %1
@@ -1261,6 +1261,65 @@ bb0(%0 : @owned $Agg3, %1 : $*Agg3):
   %4 = load [copy] %3 : $*Klass
   return %4 : $Klass
 }
+
+// CHECK-LABEL: @copyaddr_trivial_from_store :
+// CHECK:         [[B:%.*]] = begin_borrow %1
+// CHECK:         [[I:%.*]] = struct_extract [[B]] : $Agg3, #Agg3.i
+// CHECK:         end_borrow [[B]]
+// CHECK:         store %1 to [assign] %2
+// CHECK:         store [[I]] to [trivial] %0
+// CHECK:       } // end sil function 'copyaddr_trivial_from_store'
+sil [ossa] @copyaddr_trivial_from_store : $@convention(thin) (@owned Agg3, @inout Agg3) -> @out Int {
+bb0(%0 : $*Int, %1 : @owned $Agg3, %2 : $*Agg3):
+  store %1 to [assign] %2
+  %3 = struct_element_addr %2, #Agg3.i
+  copy_addr %3 to %0
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: @copyaddr_copy_from_store :
+// CHECK:         [[B:%.*]] = begin_borrow %1
+// CHECK:         [[K:%.*]] = struct_extract [[B]] : $Agg3, #Agg3.k
+// CHECK:         [[C:%.*]] = copy_value [[K]]
+// CHECK:         end_borrow [[B]]
+// CHECK:         store %1 to [assign] %2
+// CHECK:         store [[C]] to [init] %0
+// CHECK:       } // end sil function 'copyaddr_copy_from_store'
+sil [ossa] @copyaddr_copy_from_store : $@convention(thin) (@owned Agg3, @inout Agg3) -> @out Klass {
+bb0(%0 : $*Klass, %1 : @owned $Agg3, %2 : $*Agg3):
+  store %1 to [assign] %2
+  %3 = struct_element_addr %2, #Agg3.k
+  copy_addr %3 to [init] %0
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil [ossa] @split_copyaddr :
+// CHECK:         [[A:%.*]] = tuple_element_addr %0 : $*(Agg3, Klass), 0
+// CHECK:         [[KA:%.*]] = struct_element_addr %11 : $*Agg3, #Agg3.k
+// CHECK:         store %1 to [init] [[KA]] : $*Klass
+// CHECK:         [[KI:%.*]] = struct_element_addr %11 : $*Agg3, #Agg3.i
+// CHECK:         store %2 to [trivial] [[KI]] : $*Int
+// CHECK:         [[I:%.*]] = tuple_element_addr %0 : $*(Agg3, Klass), 1
+// CHECK:         store %3 to [init] [[I]] : $*Klass
+// CHECK:       } // end sil function 'split_copyaddr'
+sil [ossa] @split_copyaddr : $@convention(thin) (@owned Klass, Int, @owned Klass) -> @out (Agg3, Klass) {
+bb0(%0 : $*(Agg3, Klass), %1 : @owned $Klass, %2 : $Int, %3 : @owned $Klass):
+  %4 = alloc_stack $(Agg3, Klass)
+  %5 = tuple_element_addr %4, 0
+  %6 = tuple_element_addr %4, 1
+  %7 = struct_element_addr %5, #Agg3.k
+  %8 = struct_element_addr %5, #Agg3.i
+  store %1 to [init] %7
+  store %2 to [trivial] %8
+  store %3 to [init] %6
+  copy_addr [take] %4 to [init] %0
+  dealloc_stack %4
+  %r = tuple ()
+  return %r
+}
+
 // CHECK-LABEL: @load_take_from_store_assign :
 // CHECK:         [[DS:%.*]] = destructure_struct %0
 // CHECK:         [[TADDR:%.*]] =  struct_element_addr %1 : $*Agg2, #Agg2.t
@@ -1281,6 +1340,26 @@ bb0(%0 : @owned $Agg2, %1 : $*Agg2, %2 : @owned $Klass):
   return %6 : $Klass
 }
 
+// CHECK-LABEL: @copyaddr_take_from_store_assign :
+// CHECK:         [[DS:%.*]] = destructure_struct %1
+// CHECK:         [[TADDR:%.*]] =  struct_element_addr %2 : $*Agg2, #Agg2.t
+// CHECK:         ([[T0:%.*]], [[T1:%.*]]) = destructure_tuple [[DS]]
+// CHECK:         [[TA0:%.*]] = tuple_element_addr [[TADDR]] : $*(Klass, Klass), 0
+// CHECK:         destroy_addr [[TA0]]
+// CHECK:         [[TA1:%.*]] = tuple_element_addr [[TADDR]] : $*(Klass, Klass), 1
+// CHECK:         store [[T0]] to [init] %0
+// CHECK:       } // end sil function 'copyaddr_take_from_store_assign'
+sil [ossa] @copyaddr_take_from_store_assign : $@convention(thin) (@owned Agg2, @inout Agg2, @owned Klass) -> @out Klass {
+bb0(%0: $*Klass, %1 : @owned $Agg2, %2 : $*Agg2, %3 : @owned $Klass):
+  store %1 to [assign] %2
+  %4 = struct_element_addr %2, #Agg2.t
+  %5 = tuple_element_addr %4, 0
+  copy_addr [take] %5 to [init] %0
+  store %3 to [init] %5
+  %r = tuple ()
+  return %r
+}
+
 // CHECK-LABEL: @load_take_from_store_init :
 // CHECK:         [[DS:%.*]] = destructure_struct %0
 // CHECK:         [[TADDR:%.*]] = struct_element_addr %1 : $*Agg2, #Agg2.t
diff --git a/test/SILOptimizer/redundant_load_elim_ossa.sil b/test/SILOptimizer/redundant_load_elim_ossa.sil
index 2084ba1154ff9..31f4fa7f2c1df 100644
--- a/test/SILOptimizer/redundant_load_elim_ossa.sil
+++ b/test/SILOptimizer/redundant_load_elim_ossa.sil
@@ -1708,6 +1708,24 @@ bb0(%0 : $*ExistentialIntPair, %1 : $*ExistentialIntPair):
   return %4
 }
 
+sil @returns_tuple : $@convention(thin) () -> (Int64, @out UInt64)
+
+// CHECK-LABEL: sil [ossa] @aliasing_apply_with_direct_and_indirect_result :
+// CHECK:         apply
+// CHECK:         [[L:%.*]] = load
+// CHECK:         return [[L]]
+// CHECK-LABEL: } // end sil function 'aliasing_apply_with_direct_and_indirect_result'
+sil [ossa] @aliasing_apply_with_direct_and_indirect_result : $@convention(thin) (UInt64) -> UInt64 {
+bb0(%0 : $UInt64):
+  %4 = alloc_stack $UInt64
+  store %0 to [trivial] %4
+  %11 = function_ref @returns_tuple : $@convention(thin) () -> (Int64, @out UInt64)
+  %12 = apply %11(%4) : $@convention(thin) () -> (Int64, @out UInt64)
+  %13 = load [trivial] %4
+  dealloc_stack %4
+  return %13
+}
+
 // CHECK-LABEL: sil [ossa] @struct_of_optional_none :
 // CHECK:         [[E:%.*]] = enum
 // CHECK:         [[S:%.*]] = struct $S ([[E]] : $Optional<String>)
@@ -1743,3 +1761,39 @@ bb0(%0 : $Int):
   dealloc_stack %3
   return %6
 }
+
+// CHECK-LABEL: sil [ossa] @vector :
+// CHECK:         return %1
+// CHECK-LABEL: } // end sil function 'vector'
+sil [ossa] @vector : $@convention(thin) (@inout Builtin.FixedArray<10, Int>, Int, Int) -> Int {
+bb0(%0 : $*Builtin.FixedArray<10, Int>, %1 : $Int, %2 : $Int):
+  %3 = vector_base_addr %0
+  %4 = integer_literal $Builtin.Word, 1
+  %5 = index_addr %3, %4
+  store %1 to [trivial] %5
+  store %2 to [trivial] %3
+  %6 = load [trivial] %5
+  return %6
+}
+
+sil @forwardPtr : $@convention(thin) (Builtin.RawPointer) -> UnsafeMutableRawBufferPointer {
+[global: read]
+}
+
+// CHECK-LABEL: sil [ossa] @escaping_pointer_through_function :
+// CHECK:         [[LD:%.*]] = load [trivial] %1
+// CHECK:         return [[LD]]
+// CHECK-LABEL: } // end sil function 'escaping_pointer_through_function'
+sil [ossa] @escaping_pointer_through_function : $@convention(thin) (Int) -> Int {
+bb0(%0 : $Int):
+  %1 = alloc_stack $Int
+  store %0 to [trivial] %1
+  %3 = address_to_pointer %1 to $Builtin.RawPointer
+  %4 = function_ref @forwardPtr : $@convention(thin) (Builtin.RawPointer) -> UnsafeMutableRawBufferPointer
+  %5 = apply %4(%3) : $@convention(thin) (Builtin.RawPointer) -> UnsafeMutableRawBufferPointer
+  %6 = apply undef(%5) : $@convention(thin) (UnsafeMutableRawBufferPointer) -> ()
+  %7 = load [trivial] %1
+  dealloc_stack %1
+  return %7
+}
+
diff --git a/test/SILOptimizer/retain_release_code_motion.sil b/test/SILOptimizer/retain_release_code_motion.sil
index d5a26d8c5edcf..97f1208b97064 100644
--- a/test/SILOptimizer/retain_release_code_motion.sil
+++ b/test/SILOptimizer/retain_release_code_motion.sil
@@ -1138,3 +1138,35 @@ bb0(%0 : $B, %1: $B):
   return %5 : $()
 }
 
+enum NCEnum : ~Copyable {
+  case some([Int])
+  case none
+}
+
+sil @use_ncenum : $@convention(thin) (@guaranteed Array<Int>) -> ()
+
+// CHECK-LABEL: sil hidden @testNoncopyable : $@convention(thin) (@guaranteed NCEnum) -> () {
+// CHECK-NOT: retain_value %0
+// CHECK: retain_value
+// CHECK-LABEL: } // end sil function 'testNoncopyable'
+sil hidden @testNoncopyable : $@convention(thin) (@guaranteed NCEnum) -> () {
+bb0(%0 : $NCEnum):
+  switch_enum %0, case #NCEnum.none!enumelt: bb1, case #NCEnum.some!enumelt: bb2
+
+bb1:
+  br bb3
+
+bb2(%4 : $Array<Int>):
+  %5 = alloc_stack [var_decl] $Array<Int>, var, name "array"
+  retain_value %4
+  store %4 to %5
+  %11 = function_ref @use_ncenum : $@convention(thin) (@guaranteed Array<Int>) -> ()
+  %12 = apply %11(%4) : $@convention(thin) (@guaranteed Array<Int>) -> ()
+  destroy_addr %5
+  dealloc_stack %5
+  br bb3
+bb3:
+  %16 = tuple ()
+  return %16
+}
+
diff --git a/test/SILOptimizer/semantic-arc-opt-unchecked-ownership-conversion.sil b/test/SILOptimizer/semantic-arc-opt-unchecked-ownership-conversion.sil
index 19d92224d3f46..476cb7c92a14c 100644
--- a/test/SILOptimizer/semantic-arc-opt-unchecked-ownership-conversion.sil
+++ b/test/SILOptimizer/semantic-arc-opt-unchecked-ownership-conversion.sil
@@ -1,7 +1,5 @@
 // RUN: %target-sil-opt -module-name Swift -enable-sil-verify-all -semantic-arc-opts -sil-semantic-arc-peepholes-ownership-conversion-elim -sil-semantic-arc-peepholes-lifetime-joining %s | %FileCheck %s
 
-// REQUIRES: asserts
-
 sil_stage canonical
 
 import Builtin
diff --git a/test/SILOptimizer/semantic-arc-opts-lifetime-joining.sil b/test/SILOptimizer/semantic-arc-opts-lifetime-joining.sil
index adaf353d302ad..1e1a7c0c55b4a 100644
--- a/test/SILOptimizer/semantic-arc-opts-lifetime-joining.sil
+++ b/test/SILOptimizer/semantic-arc-opts-lifetime-joining.sil
@@ -1,7 +1,4 @@
 // RUN: %target-sil-opt -sil-print-types -module-name Swift -enable-sil-verify-all -semantic-arc-opts -sil-semantic-arc-peepholes-lifetime-joining %s | %FileCheck %s
-//
-// Enabling specific ARC opts requires an asserts build.
-// REQUIRES: asserts
 
 // NOTE: Some of our tests here depend on borrow elimination /not/ running!
 // Please do not add it to clean up the IR like we did in
@@ -978,3 +975,42 @@ bb0:
   return %r : $()
 }
 
+sil @consume_and_borrow : $@convention(thin) (@owned Klass, @guaranteed Klass) -> ()
+sil @borrow : $@convention(thin) (@guaranteed Klass) -> ()
+sil @consume : $@convention(thin) (@owned Klass) -> ()
+sil @get_klass : $@convention(thin) () -> @owned Klass
+
+// CHECK-LABEL: sil hidden [ossa] @borrow_and_consume_copyable_test1 :
+// CHECK-NOT: copy_value
+// CHECK-LABEL: } // end sil function 'borrow_and_consume_copyable_test1'
+sil hidden [ossa] @borrow_and_consume_copyable_test1 : $@convention(thin) () -> () {
+bb0:
+  %0 = function_ref @get_klass : $@convention(thin) () -> @owned Klass
+  %1 = apply %0() : $@convention(thin) () -> @owned Klass
+  %2 = move_value [var_decl] %1
+  %3 = copy_value %2
+  %4 = function_ref @borrow : $@convention(thin) (@guaranteed Klass) -> ()
+  %5 = apply %4(%2) : $@convention(thin) (@guaranteed Klass) -> ()
+  %6 = function_ref @consume : $@convention(thin) (@owned Klass) -> ()
+  %7 = apply %6(%3) : $@convention(thin) (@owned Klass) -> ()
+  destroy_value %2
+  %9 = tuple ()
+  return %9
+}
+
+// CHECK-LABEL: sil hidden [ossa] @borrow_and_consume_copyable_test2 : 
+// CHECK: copy_value
+// CHECK-LABEL: } // end sil function 'borrow_and_consume_copyable_test2'
+sil hidden [ossa] @borrow_and_consume_copyable_test2 : $@convention(thin) () -> () {
+bb0:
+  %0 = function_ref @get_klass : $@convention(thin) () -> @owned Klass
+  %1 = apply %0() : $@convention(thin) () -> @owned Klass
+  %2 = move_value [var_decl] %1
+  %3 = copy_value %2
+  %4 = function_ref @consume_and_borrow : $@convention(thin) (@owned Klass, @guaranteed Klass) -> ()
+  %5 = apply %4(%3, %2) : $@convention(thin) (@owned Klass, @guaranteed Klass) -> ()
+  destroy_value %2
+  %7 = tuple ()
+  return %7
+}
+
diff --git a/test/SILOptimizer/semantic-arc-opts-redundantcopyopts.sil b/test/SILOptimizer/semantic-arc-opts-redundantcopyopts.sil
index 275aecb8599a9..150c05953bcd5 100644
--- a/test/SILOptimizer/semantic-arc-opts-redundantcopyopts.sil
+++ b/test/SILOptimizer/semantic-arc-opts-redundantcopyopts.sil
@@ -1,5 +1,4 @@
 // RUN: %target-sil-opt -module-name Swift -enable-sil-verify-all -semantic-arc-opts -sil-semantic-arc-peepholes-redundant-copyvalue-elim %s | %FileCheck %s
-// REQUIRES: swift_stdlib_asserts
 
 // NOTE: Some of our tests here depend on borrow elimination /not/ running!
 // Please do not add it to clean up the IR like we did in
@@ -59,6 +58,11 @@ extension Klass : MyFakeAnyObject {
 sil [ossa] @guaranteed_klass_user : $@convention(thin) (@guaranteed Klass) -> ()
 sil [ossa] @guaranteed_fakeoptional_klass_user : $@convention(thin) (@guaranteed FakeOptional<Klass>) -> ()
 sil [ossa] @guaranteed_fakeoptional_classlet_user : $@convention(thin) (@guaranteed FakeOptional<ClassLet>) -> ()
+sil [ossa] @create_klass : $@convention(thin) () -> @owned Klass
+
+struct ContainsKlass {
+  var x: Klass
+}
 
 struct MyInt {
   var value: Builtin.Int32
@@ -186,3 +190,51 @@ bb3:
   return %9999 : $()
 }
 
+// CHECK-LABEL: sil [ossa] @copy_in_deadend_block :
+// CHECK:         copy_value
+// CHECK:       } // end sil function 'copy_in_deadend_block'
+sil [ossa] @copy_in_deadend_block : $@convention(thin) (@inout ContainsKlass) -> () {
+bb0(%1 : $*ContainsKlass):
+  %129 = function_ref @create_klass : $@convention(thin) () -> @owned Klass
+  %130 = apply %129() : $@convention(thin) () -> @owned Klass
+  %131 = copy_value %130
+  %133 = struct $ContainsKlass (%130)
+  store %133 to [assign] %1
+  fix_lifetime %131
+  destroy_value %131
+  unreachable
+}
+
+public struct Wrapper {
+  var _k: Klass
+}
+
+sil @get_wrapper : $@convention(thin) () -> @owned Wrapper
+sil @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+
+sil [ossa] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+bb0(%0 : @guaranteed $Wrapper):
+  %2 = struct_extract %0, #Wrapper._k
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @test_borrow_accessor_opt :
+// CHECK-NOT: copy_value
+// CHECK-LABEL: } // end sil function 'test_borrow_accessor_opt'
+sil [ossa] @test_borrow_accessor_opt : $@convention(thin) () -> () {
+bb0:
+  %1 = function_ref @get_wrapper : $@convention(thin) () -> @owned Wrapper
+  %2 = apply %1() : $@convention(thin) () -> @owned Wrapper
+  %3 = begin_borrow %2
+  %4 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %5 = apply %4(%3) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %copy = copy_value %5
+  %6 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %7 = apply %6(%copy) : $@convention(thin) (@guaranteed Klass) -> ()
+  destroy_value %copy
+  end_borrow %3
+  destroy_value %2
+  %10 = tuple ()
+  return %10
+}
+
diff --git a/test/SILOptimizer/semantic-arc-opts-unit.sil b/test/SILOptimizer/semantic-arc-opts-unit.sil
new file mode 100644
index 0000000000000..2c957c0bcef90
--- /dev/null
+++ b/test/SILOptimizer/semantic-arc-opts-unit.sil
@@ -0,0 +1,41 @@
+// RUN: %target-sil-opt -test-runner %s -o /dev/null 2>&1 | %FileCheck %s
+
+sil_stage canonical
+
+import Builtin
+import Swift
+
+struct Inner {
+  var o: Builtin.NativeObject
+}
+struct Outer {
+  var inner: Inner
+}
+
+// CHECK-LABEL: sil [ossa] @check_keep_copy_required_to_destroy_at_unreachable : {{.*}} {
+// CHECK:         copy_value
+// CHECK-LABEL: } // end sil function 'check_keep_copy_required_to_destroy_at_unreachable'
+sil [ossa] @check_keep_copy_required_to_destroy_at_unreachable : $@convention(thin) (@in_guaranteed Outer) -> () {
+entry(%o_addr : $*Outer):
+  %o_copy = load [copy] %o_addr : $*Outer
+  %o_borrow = begin_borrow %o_copy : $Outer
+  %i = struct_extract %o_borrow : $Outer, #Outer.inner
+  %i_copy = copy_value %i : $Inner
+  specify_test "semantic_arc_opts__copy_value_opts__guaranteed_value_opt %i_copy"
+  (%o2_addr, %token) = begin_apply undef(%i_copy) : $@yield_once @convention(thin) (@guaranteed Inner) -> @yields @inout Outer
+  try_apply undef(%o2_addr) : $@convention(thin) (@inout Outer) -> @error any Error, normal success, error failure
+
+success(%empty : $()):
+  end_apply %token as $()
+  destroy_value %i_copy : $Inner
+  end_borrow %o_borrow : $Outer
+  destroy_value %o_copy : $Outer
+  return undef : $()
+
+failure(%error : @owned $any Error):
+  end_borrow %o_borrow : $Outer
+  destroy_value %error : $any Error
+  end_apply %token as $()
+  destroy_value [dead_end] %o_copy : $Outer
+  unreachable
+}
diff --git a/test/SILOptimizer/shrink_borrow_scope.swift b/test/SILOptimizer/shrink_borrow_scope.swift
index 6cfb9aeb935e1..f7d28621e66b0 100644
--- a/test/SILOptimizer/shrink_borrow_scope.swift
+++ b/test/SILOptimizer/shrink_borrow_scope.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -c -O -enable-copy-propagation=true -enable-lexical-lifetimes=true -sil-verify-all -Xllvm -sil-print-final-ossa-module %s | %FileCheck %s
+// RUN: %target-swift-frontend -c -O -enable-copy-propagation=optimizing -enable-lexical-lifetimes=true -sil-verify-all -Xllvm -sil-print-final-ossa-module %s | %FileCheck %s
 
 // =============================================================================
 // = DECLARATIONS                                                             {{
diff --git a/test/SILOptimizer/shrink_borrow_scope.unit.sil b/test/SILOptimizer/shrink_borrow_scope.unit.sil
index f3544ada8cdbb..3b875519d91ee 100644
--- a/test/SILOptimizer/shrink_borrow_scope.unit.sil
+++ b/test/SILOptimizer/shrink_borrow_scope.unit.sil
@@ -67,3 +67,37 @@ exit:
   %retval = tuple ()
   return %retval : $()
 }
+
+class Klass {}
+
+public struct Wrapper {
+  var _k: Klass
+}
+
+sil @get_wrapper : $@convention(thin) () -> @owned Wrapper
+sil @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+
+sil [ossa] @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass {
+bb0(%0 : @guaranteed $Wrapper):
+  %2 = struct_extract %0, #Wrapper._k
+  return %2
+}
+
+// CHECK-LABEL: begin running test {{.*}} on test_borrow_accessor_noopt
+// CHECK:       Result: did not shrink
+// CHECK-LABEL: end running test {{.*}} on test_borrow_accessor_noopt
+sil [ossa] @test_borrow_accessor_noopt : $@convention(thin) () -> () {
+bb0:
+  %1 = function_ref @get_wrapper : $@convention(thin) () -> @owned Wrapper
+  %2 = apply %1() : $@convention(thin) () -> @owned Wrapper
+  %3 = begin_borrow %2
+  specify_test "shrink_borrow_scope %3"
+  %4 = function_ref @borrow_loadable_prop : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %5 = apply %4(%3) : $@convention(method) (@guaranteed Wrapper) -> @guaranteed Klass
+  %6 = function_ref @use_klass : $@convention(thin) (@guaranteed Klass) -> ()
+  %7 = apply %6(%5) : $@convention(thin) (@guaranteed Klass) -> ()
+  end_borrow %3
+  destroy_value %2
+  %10 = tuple ()
+  return %10
+}
diff --git a/test/SILOptimizer/side_effects.sil b/test/SILOptimizer/side_effects.sil
index 080cb90b3f7a7..c30843b270432 100644
--- a/test/SILOptimizer/side_effects.sil
+++ b/test/SILOptimizer/side_effects.sil
@@ -680,6 +680,13 @@ bb0(%0 : $*X):
   return %r : $()
 }
 
+sil [_semantics "programtermination_point"] @exitfunc_defined : $@convention(thin) () -> Never {
+bb0:
+  %u = function_ref @unknown_func : $@convention(thin) () -> ()
+  %a = apply %u() : $@convention(thin) () -> ()
+  unreachable
+}
+
 // CHECK-LABEL: sil @call_noreturn
 // CHECK-NEXT:  [global: read]
 // CHECK-NEXT:  {{^[^[]}}
@@ -697,6 +704,23 @@ bb2:
   return %r : $()
 }
 
+// CHECK-LABEL: sil @call_defined_noreturn
+// CHECK-NEXT:  [global: read]
+// CHECK-NEXT:  {{^[^[]}}
+sil @call_defined_noreturn : $@convention(thin) () -> () {
+bb0:
+  cond_br undef, bb1, bb2
+
+bb1:
+  %u = function_ref @exitfunc_defined : $@convention(thin) () -> Never
+  %a = apply %u() : $@convention(thin) () -> Never
+  unreachable
+
+bb2:
+  %r = tuple ()
+  return %r : $()
+}
+
 // CHECK-LABEL: sil @call_readnone
 // CHECK-NEXT:  [global: copy,deinit_barrier]
 // CHECK-NEXT:  {{^[^[]}}
@@ -1257,3 +1281,119 @@ bb0(%0: $any Error):
   %r = tuple ()
   return %r : $()
 }
+
+// Base case: @destroy_not_escaped_closure_test. It has every global and argument effect, so we can see which are removed.
+// CHECK-LABEL: sil [readnone] @test_effect_attribute_readnone
+// CHECK-NEXT:  [global: copy,deinit_barrier]
+// CHECK-NEXT:  {{^[^[]}}
+// CHECK-LABEL: } // end sil function 'test_effect_attribute_readnone'
+sil [readnone] @test_effect_attribute_readnone : $@convention(thin)(@owned @callee_guaranteed () -> ()) -> Builtin.Int1 {
+bb0(%0 : $@callee_guaranteed () -> ()):
+  %1 = destroy_not_escaped_closure %0: $@callee_guaranteed () -> ()
+  return %1 : $Builtin.Int1
+}
+
+// CHECK-LABEL: sil [readonly] @test_effect_attribute_readonly
+// CHECK-NEXT:  [%0: read v**.c*.v**, copy v**.c*.v**]
+// CHECK-NEXT:  [global: read,copy,deinit_barrier]
+// CHECK-NEXT:  {{^[^[]}}
+// CHECK-LABEL: } // end sil function 'test_effect_attribute_readonly'
+sil [readonly] @test_effect_attribute_readonly : $@convention(thin)(@owned @callee_guaranteed () -> ()) -> Builtin.Int1 {
+bb0(%0 : $@callee_guaranteed () -> ()):
+  %1 = destroy_not_escaped_closure %0: $@callee_guaranteed () -> ()
+  return %1 : $Builtin.Int1
+}
+
+// CHECK-LABEL: sil [releasenone] @test_effect_attribute_releasenone
+// CHECK-NEXT:  [%0: read v**.c*.v**, write v**.c*.v**, copy v**.c*.v**]
+// CHECK-NEXT:  [global: read,write,copy,allocate,deinit_barrier]
+// CHECK-NEXT:  {{^[^[]}}
+// CHECK-LABEL: } // end sil function 'test_effect_attribute_releasenone'
+sil [releasenone] @test_effect_attribute_releasenone : $@convention(thin)(@owned @callee_guaranteed () -> ()) -> Builtin.Int1 {
+bb0(%0 : $@callee_guaranteed () -> ()):
+  %1 = destroy_not_escaped_closure %0: $@callee_guaranteed () -> ()
+  return %1 : $Builtin.Int1
+}
+
+// These tests are adapted from the test case in rdar://155870190
+sil @test_effect_attribute_no_barrier : $@convention(thin) () -> () {
+  [global: ]
+}
+
+sil @test_effect_attribute_barrier : $@convention(thin) () -> () {
+  [global: deinit_barrier]
+}
+// CHECK-LABEL: sil [readnone] @test_effect_attribute_call_no_barrier
+// CHECK-NEXT:  [global: ]
+// CHECK-NEXT:  {{^[^[]}}
+// CHECK-LABEL: } // end sil function 'test_effect_attribute_call_no_barrier'
+sil [readnone] @test_effect_attribute_call_no_barrier : $@convention(thin) () -> @out Any {
+bb0(%0 : $*Any):
+  %2 = function_ref @test_effect_attribute_no_barrier : $@convention(thin) () -> ()
+  apply %2() : $@convention(thin) () -> ()
+  %4 = tuple ()
+  return %4
+}
+
+// CHECK-LABEL: sil [readnone] @test_effect_attribute_call_barrier
+// CHECK-NEXT:  [global: deinit_barrier]
+// CHECK-NEXT:  {{^[^[]}}
+// CHECK-LABEL: } // end sil function 'test_effect_attribute_call_barrier'
+sil [readnone] @test_effect_attribute_call_barrier : $@convention(thin) () -> @out Any {
+bb0(%0 : $*Any):
+  %2 = function_ref @test_effect_attribute_barrier : $@convention(thin) () -> ()
+  apply %2() : $@convention(thin) () -> ()
+  %4 = tuple ()
+  return %4
+}
+
+// The readnone attribute can not rule out reads from indirect arguments.
+// CHECK-LABEL: sil [readnone] @test_effect_attribute_readnone_direct_argument
+// CHECK-NEXT:  [global: ]
+// CHECK-NEXT:  {{^[^[]}}
+// CHECK-LABEL: } // end sil function 'test_effect_attribute_readnone_direct_argument'
+sil [readnone] @test_effect_attribute_readnone_direct_argument : $@convention(thin) (Int) -> Int {
+bb0(%0 : $Int):
+  return %0
+}
+
+// CHECK-LABEL: sil [readnone] @test_effect_attribute_readnone_indirect_argument
+// CHECK-NEXT:  [%0: read v**]
+// CHECK-NEXT:  [global: ]
+// CHECK-NEXT:  {{^[^[]}}
+// CHECK-LABEL: } // end sil function 'test_effect_attribute_readnone_indirect_argument'
+sil [readnone] @test_effect_attribute_readnone_indirect_argument : $@convention(thin) (@in Int) -> Int {
+bb0(%0 : $*Int):
+  %1 = load %0
+  return %1
+}
+
+// Base case: @retain_and_store. The indirect result has a write effect, which readnone & readonly can't rule out.
+// CHECK-LABEL: sil [readnone] @test_effect_attribute_readnone_indirect_result
+// CHECK-NEXT:  [%0: write v**]
+// CHECK-NEXT:  [global: ]
+// CHECK-NEXT:  {{^[^[]}}
+// CHECK-LABEL: } // end sil function 'test_effect_attribute_readnone_indirect_result'
+sil [readnone] @test_effect_attribute_readnone_indirect_result : $@convention(thin) (@guaranteed X) -> @out X {
+bb0(%0 : $*X, %1 : $X):
+  strong_retain %1 : $X
+  store %1 to %0  : $*X
+
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [readonly] @test_effect_attribute_readonly_indirect_result
+// CHECK-NEXT:  [%0: write v**]
+// CHECK-NEXT:  [%1: copy v**]
+// CHECK-NEXT:  [global: ]
+// CHECK-NEXT:  {{^[^[]}}
+// CHECK-LABEL: } // end sil function 'test_effect_attribute_readonly_indirect_result'
+sil [readonly] @test_effect_attribute_readonly_indirect_result : $@convention(thin) (@guaranteed X) -> @out X {
+bb0(%0 : $*X, %1 : $X):
+  strong_retain %1 : $X
+  store %1 to %0  : $*X
+
+  %r = tuple ()
+  return %r : $()
+}
diff --git a/test/SILOptimizer/sil_cloner_no_substitution_map.sil b/test/SILOptimizer/sil_cloner_no_substitution_map.sil
new file mode 100644
index 0000000000000..dc0dc95e9d44a
--- /dev/null
+++ b/test/SILOptimizer/sil_cloner_no_substitution_map.sil
@@ -0,0 +1,44 @@
+// RUN: %target-sil-opt %s -mandatory-allocbox-to-stack
+
+// This tickled a bug in the SILCloner that was caught by the verifier.
+
+sil_stage raw
+
+import Builtin
+import Swift
+import SwiftShims
+
+protocol P {
+    associatedtype A
+}
+
+protocol Q: AnyObject {
+}
+
+struct S: P {
+  typealias A = Int
+}
+
+sil [ossa] @testit : $@convention(thin) (Int, @guaranteed any Q, @in_guaranteed Int, @in_guaranteed S) -> () {
+bb0(%0 : $Int, %3 : @guaranteed $any Q, %4 : $*Int, %5 : $*S):
+  %6 = alloc_box ${ var Int }, var, name "duration"
+  %7 = begin_borrow [var_decl] %6
+  %8 = project_box %7, 0
+  store %0 to [trivial] %8
+  %66 = function_ref @closure : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == τ_0_1.A, τ_0_1 : P> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_1, @guaranteed { var Int }, @guaranteed any Q) -> ()
+  %67 = apply %66<Int, S>(%4, %5, %7, %3) : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == τ_0_1.A, τ_0_1 : P> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_1, @guaranteed { var Int }, @guaranteed any Q) -> ()
+  end_borrow %7
+  destroy_value %6
+  %75 = tuple ()
+  return %75
+}
+
+sil private [ossa] @closure : $@convention(thin) <T, V where T == V.A, V : P> (@in_guaranteed T, @in_guaranteed V, @guaranteed { var Int }, @guaranteed any Q) -> () {
+bb0(%0 : $*T, %1 : $*V, %2 : @closureCapture @guaranteed ${ var Int }, %3 : @closureCapture @guaranteed $any Q):
+  %13 = open_existential_ref %3 to $@opened("891BD9C8-56A2-11F0-A4DF-0EA13E3AABAF", any Q) Self
+  %17 = apply undef<@opened("891BD9C8-56A2-11F0-A4DF-0EA13E3AABAF", any Q) Self, V>(%0, %1) : $@convention(thin) <τ_0_0><τ_1_0 where τ_1_0 : P> (@in_guaranteed τ_1_0.A, @in_guaranteed τ_1_0) -> ()
+  %20 = tuple ()
+  return %20
+}
+
+
diff --git a/test/SILOptimizer/sil_combine.sil b/test/SILOptimizer/sil_combine.sil
index 8eeee3e39c2ce..d2eb895253f7a 100644
--- a/test/SILOptimizer/sil_combine.sil
+++ b/test/SILOptimizer/sil_combine.sil
@@ -2453,7 +2453,6 @@ bb0(%0 : $Builtin.Int1):
 }
 
 // CHECK-LABEL: sil @builtin_array_opt_index_raw_pointer_to_index_addr
-// CHECK:  [[MT:%.*]] = metatype $@thick Int32.Type
 // CHECK:  [[ONE:%.*]] = integer_literal $Builtin.Word, 1
 // CHECK:  [[PTA1:%.*]] = pointer_to_address %1 : $Builtin.RawPointer to [strict] $*Int32
 // CHECK:  [[CAST1:%.*]] = builtin "truncOrBitCast_Int64_Word"(%0 : $Builtin.Int64)
@@ -2463,7 +2462,8 @@ bb0(%0 : $Builtin.Int1):
 // CHECK:  [[CAST2:%.*]] = builtin "truncOrBitCast_Int64_Word"(%0 : $Builtin.Int64)
 // CHECK:  [[IAD2:%.*]] = index_addr [[PTA2]] : $*Int32, [[CAST2]] : $Builtin.Word
 // CHECK:  [[ATP2:%.*]] = address_to_pointer [[IAD2]] : $*Int32 to $Builtin.RawPointer
-// CHECK:  builtin "takeArrayFrontToBack"<Int32>([[MT]] : $@thick Int32.Type, [[ATP1]] : $Builtin.RawPointer, [[ATP2]] : $Builtin.RawPointer, [[ONE]] : $Builtin.Word) : $()
+// CHECK:  [[MT:%.*]] = metatype $@thin Int32.Type
+// CHECK:  builtin "takeArrayFrontToBack"<Int32>([[MT]] : $@thin Int32.Type, [[ATP1]] : $Builtin.RawPointer, [[ATP2]] : $Builtin.RawPointer, [[ONE]] : $Builtin.Word) : $()
 // CHECK: return
 
 sil @builtin_array_opt_index_raw_pointer_to_index_addr : $@convention(thin) (Builtin.Int64, Builtin.RawPointer, Builtin.RawPointer) -> () {
@@ -2870,11 +2870,9 @@ bb0(%0 : $Builtin.NativeObject):
 
 // CHECK-LABEL: sil @test_cmp_xor_canonicalization
 // CHECK:bb0([[ARG:%.*]] : $Builtin.Int1
-// CHECK:  [[TRUE:%.*]] = integer_literal $Builtin.Int1, -1
 // CHECK:  [[FALSE:%.*]] = integer_literal $Builtin.Int1, 0
-// CHECK:  [[EQ:%.*]] = builtin "cmp_eq_Int1"([[ARG]] : $Builtin.Int1, [[FALSE]]
-// CHECK:  [[NOT:%.*]] = builtin "xor_Int1"([[EQ]] : $Builtin.Int1, [[TRUE]] : $Builtin.Int1)
-// CHECK:  return [[NOT]]
+// CHECK:  [[NE:%.*]] = builtin "cmp_ne_Int1"([[ARG]] : $Builtin.Int1, [[FALSE]]
+// CHECK:  return [[NE]]
 
 sil @test_cmp_xor_canonicalization : $@convention(thin) (Builtin.Int1) -> Builtin.Int1 {
 bb0(%0 : $Builtin.Int1):
@@ -3759,12 +3757,9 @@ bb2(%5 : $MyErrorType):
 }
 
 // CHECK-LABEL: sil @mark_dependence_base
-// CHECK: bb0(
-// CHECK-NOT: init_existential_ref
-// CHECK-NOT: enum
-// CHECK-NEXT: mark_dependence
-// CHECK-NEXT: load
-// CHECK: return
+// CHECK:        [[MD:%.*]] = mark_dependence %0 : $*Builtin.Int64 on %1 : $B
+// CHECK-NEXT:   load [[MD]]
+// CHECK:       } // end sil function 'mark_dependence_base'
 sil @mark_dependence_base : $@convention(thin) (@inout Builtin.Int64, @owned B) -> Builtin.Int64 {
 bb0(%0 : $*Builtin.Int64, %1 : $B):
   %x = init_existential_ref %1 : $B : $B, $AnyObject
@@ -3788,10 +3783,8 @@ bb0(%0 : $B):
 }
 
 // CHECK-LABEL: sil @mark_dependence_trivial_address_base :
-// CHECK: bb0(
-// CHECK-NEXT: strong_retain
-// CHECK-NEXT: return
-// CHECK: } // end sil function 'mark_dependence_trivial_address_base'
+// CHECK:         mark_dependence
+// CHECK:       } // end sil function 'mark_dependence_trivial_address_base'
 sil @mark_dependence_trivial_address_base : $@convention(thin) (@guaranteed B) -> @owned B {
 bb0(%0 : $B):
   strong_retain %0 : $B
@@ -3804,12 +3797,9 @@ bb0(%0 : $B):
 protocol _NSArrayCore {}
 
 // CHECK-LABEL: sil @mark_dependence_base2
-// CHECK: bb0(
-// CHECK-NOT: open_existential_ref
-// CHECK-NOT: enum
-// CHECK-NEXT: mark_dependence
-// CHECK-NEXT: load
-// CHECK: return
+// CHECK:        [[MD:%.*]] = mark_dependence %0 : $*Builtin.Int64 on %1 : $B
+// CHECK-NEXT:   load [[MD]]
+// CHECK:       } // end sil function 'mark_dependence_base2'
 sil @mark_dependence_base2 : $@convention(thin) (@inout Builtin.Int64, @owned B) -> Builtin.Int64 {
 bb0(%0 : $*Builtin.Int64, %1 : $B):
   %2 = init_existential_ref %1 : $B : $B, $AnyObject
diff --git a/test/SILOptimizer/sil_combine1.swift b/test/SILOptimizer/sil_combine1.swift
index 6297ac850ef66..aad1d654fa4e6 100644
--- a/test/SILOptimizer/sil_combine1.swift
+++ b/test/SILOptimizer/sil_combine1.swift
@@ -1,5 +1,4 @@
 // RUN: %target-swift-frontend %s -O -Xllvm -sil-print-types -emit-sil | %FileCheck %s
-// RUN: %target-swift-frontend %s -O -Xllvm -sil-print-types -enable-ossa-modules -emit-sil | %FileCheck %s
 
 func curry<T1, T2, T3, T4>(_ f: @escaping (T1, T2, T3) -> T4) -> (T1) -> (T2) -> (T3) -> T4 {
   return { x in { y in { z in f(x, y, z) } } }
@@ -36,3 +35,9 @@ public func test_compose_closure() -> Int32 {
   return gs
 }
 
+// CHECK-LABEL: sil @$s12sil_combine122remove_partial_applies_3key5valueySDySSSiGSgz_SSSitF :
+// CHECK-NOT:     partial_apply
+// CHECK:       } // end sil function '$s12sil_combine122remove_partial_applies_3key5valueySDySSSiGSgz_SSSitF'
+public func remove_partial_applies(_ dict: inout [String: Int]?, key: String, value: Int) {
+  dict?[key, default: value] = value 
+}
diff --git a/test/SILOptimizer/sil_combine_apply.sil b/test/SILOptimizer/sil_combine_apply.sil
index 6b40315f21eb2..b57aa9cad8a44 100644
--- a/test/SILOptimizer/sil_combine_apply.sil
+++ b/test/SILOptimizer/sil_combine_apply.sil
@@ -570,6 +570,24 @@ bb0:
   return %return : $()
 }
 
+class GenC<T> {
+}
+
+sil @takeGenC : $@convention(thin) <τ_0_0> (@owned GenC<τ_0_0>) -> ()
+
+// CHECK-LABEL: sil [ossa] @convert_function_with_generic_arg :
+// CHECK:         [[C:%.*]] = convert_function
+// CHECK:         apply [[C]]
+// CHECK:       } // end sil function 'convert_function_with_generic_arg'
+sil [ossa] @convert_function_with_generic_arg : $@convention(thin) (@owned AnyObject) -> () {
+bb0(%0 : @owned $AnyObject):
+  %2 = function_ref @takeGenC : $@convention(thin) <τ_0_0> (@owned GenC<τ_0_0>) -> ()
+  %9 = convert_function %2 to $@convention(thin) (@owned AnyObject) -> ()
+  %30 = apply %9(%0) : $@convention(thin) (@owned AnyObject) -> ()
+  %r = tuple ()
+  return %r
+}
+
 sil shared [transparent] [thunk] @genericClosure : $@convention(thin) <T> (@in T) -> @out T {
 bb0(%0 : $*T, %1 : $*T):
   %12 = tuple ()
diff --git a/test/SILOptimizer/sil_combine_apply_ossa.sil b/test/SILOptimizer/sil_combine_apply_ossa.sil
index 0ac3f63a5fd79..dbaca018691f0 100644
--- a/test/SILOptimizer/sil_combine_apply_ossa.sil
+++ b/test/SILOptimizer/sil_combine_apply_ossa.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enable-ossa-modules -enable-copy-propagation -enable-lexical-lifetimes=false -enable-sil-verify-all %s -sil-combine -sil-combine-disable-alloc-stack-opts | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-copy-propagation -enable-lexical-lifetimes=false -enable-sil-verify-all %s -sil-combine -sil-combine-disable-alloc-stack-opts | %FileCheck %s
 
 import Swift
 import Builtin
@@ -1172,6 +1172,37 @@ bb0(%0 : $Int):
   return %r : $()
 }
 
+// CHECK-LABEL: sil [ossa] @test_mark_dependence_of_closure :
+// CHECK-NOT:     partial_apply
+// CHECK-LABEL: } // end sil function 'test_mark_dependence_of_closure'
+sil [ossa] @test_mark_dependence_of_closure : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %3 = function_ref @closure2 : $@convention(thin) (Int) -> ()
+  %4 = partial_apply %3(%0) : $@convention(thin) (Int) -> ()
+  %5 = convert_function %4 to $@callee_owned () -> ()
+  %6 = convert_escape_to_noescape %5 to $@noescape @callee_owned () -> ()
+  %7 = mark_dependence %6 on %5
+  apply %7() : $@noescape @callee_owned () -> ()
+  destroy_value %5
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [ossa] @test_dead_closure_with_mark_dependence :
+// CHECK-NOT:     partial_apply
+// CHECK-LABEL: } // end sil function 'test_dead_closure_with_mark_dependence'
+sil [ossa] @test_dead_closure_with_mark_dependence : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %3 = function_ref @closure2 : $@convention(thin) (Int) -> ()
+  %4 = partial_apply %3(%0) : $@convention(thin) (Int) -> ()
+  %6 = convert_escape_to_noescape %4 to $@noescape @callee_owned () -> ()
+  %7 = mark_dependence %6 on %4
+  destroy_value %4
+  destroy_value %7
+  %r = tuple ()
+  return %r : $()
+}
+
 sil [ossa] @closure2 : $@convention(thin) (Int) -> ()
 
 sil [ossa] @yield1 : $@yield_once(Float) -> (@yields Float) {
diff --git a/test/SILOptimizer/sil_combine_concrete_existential_noncopyable.swift b/test/SILOptimizer/sil_combine_concrete_existential_noncopyable.swift
index fc3fb239638ef..998349137d58f 100644
--- a/test/SILOptimizer/sil_combine_concrete_existential_noncopyable.swift
+++ b/test/SILOptimizer/sil_combine_concrete_existential_noncopyable.swift
@@ -11,7 +11,7 @@ public struct S: P {
 }
 
 // CHECK-LABEL: sil @$s44sil_combine_concrete_existential_noncopyable1gyyF : $@convention(thin) () -> () {
-// CHECK: [[S_ADDR:%.*]] =  alloc_stack [var_decl] $S
+// CHECK: [[S_ADDR:%.*]] =  alloc_stack [lexical] [var_decl] $S
 // CHECK: [[INIT_FN:%.*]] = function_ref @$s44sil_combine_concrete_existential_noncopyable1SVACycfC : $@convention(method) (@thin S.Type) -> S
 // CHECK: [[S:%.*]] = apply [[INIT_FN]]({{%.*}}) : $@convention(method) (@thin S.Type) -> S
 // CHECK: store [[S]] to [[S_ADDR]]
diff --git a/test/SILOptimizer/sil_combine_concrete_existential_ossa.swift b/test/SILOptimizer/sil_combine_concrete_existential_ossa.swift
index d42cee1a6f004..8b55f020e081e 100644
--- a/test/SILOptimizer/sil_combine_concrete_existential_ossa.swift
+++ b/test/SILOptimizer/sil_combine_concrete_existential_ossa.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -O -enable-ossa-modules -Xllvm -sil-print-types -emit-sil -sil-verify-all -Xllvm -sil-disable-pass=function-signature-opts %s | %FileCheck %s
-// RUN: %target-swift-frontend -O -enable-ossa-modules -Xllvm -sil-print-types -emit-sil -Xllvm -sil-verify-force-analysis-around-pass=devirtualizer -Xllvm -sil-disable-pass=function-signature-opts %s | %FileCheck %s
+// RUN: %target-swift-frontend -O -Xllvm -sil-print-types -emit-sil -sil-verify-all -Xllvm -sil-disable-pass=function-signature-opts %s | %FileCheck %s
+// RUN: %target-swift-frontend -O -Xllvm -sil-print-types -emit-sil -Xllvm -sil-verify-force-analysis-around-pass=devirtualizer -Xllvm -sil-disable-pass=function-signature-opts %s | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 
@@ -165,8 +165,8 @@ public struct SomeStruct: ProtoB {
 // CHECK-LABEL: sil @$s37sil_combine_concrete_existential_ossa16createSomeStructAA0gH0VSgyF :
 // CHECK:         [[L:%.*]] = integer_literal $Builtin.Int64, 27
 // CHECK-NEXT:    [[I:%.*]] = struct $Int64 ([[L]] : $Builtin.Int64)
-// CHECK-NEXT:    [[S:%.*]] = struct $SomeStruct ([[I]] : $Int64)
-// CHECK-NEXT:    [[O:%.*]] = enum $Optional<SomeStruct>, #Optional.some!enumelt, [[S]] : $SomeStruct
+// CHECK:         [[S:%.*]] = struct $SomeStruct ([[I]] : $Int64)
+// CHECK:         [[O:%.*]] = enum $Optional<SomeStruct>, #Optional.some!enumelt, [[S]] : $SomeStruct
 // CHECK-NEXT:    return [[O]] : $Optional<SomeStruct>
 // CHECK:       } // end sil function '$s37sil_combine_concrete_existential_ossa16createSomeStructAA0gH0VSgyF'
 public func createSomeStruct() -> SomeStruct? {
diff --git a/test/SILOptimizer/sil_combine_global_addr.sil b/test/SILOptimizer/sil_combine_global_addr.sil
index eca3dee75f871..de19174c212da 100644
--- a/test/SILOptimizer/sil_combine_global_addr.sil
+++ b/test/SILOptimizer/sil_combine_global_addr.sil
@@ -16,7 +16,7 @@ class SomeClass  : SomeProtocol {
   func foo() -> Int
 }
 
-sil hidden [thunk] [always_inline] @foo_ : $@convention(witness_method:SomeProtocol) (@in_guaranteed SomeClass) -> Int {
+sil hidden [thunk] [heuristic_always_inline] @foo_ : $@convention(witness_method:SomeProtocol) (@in_guaranteed SomeClass) -> Int {
 bb0(%0 : $*SomeClass):
   %1 = load %0 : $*SomeClass
   %2 = class_method %1 : $SomeClass, #SomeClass.foo : (SomeClass) -> () -> Int, $@convention(method) (@guaranteed SomeClass) -> Int
diff --git a/test/SILOptimizer/sil_combine_global_addr_ossa.sil b/test/SILOptimizer/sil_combine_global_addr_ossa.sil
index c07077c7735b6..a59aba37fbad8 100644
--- a/test/SILOptimizer/sil_combine_global_addr_ossa.sil
+++ b/test/SILOptimizer/sil_combine_global_addr_ossa.sil
@@ -16,7 +16,7 @@ class SomeClass  : SomeProtocol {
   func foo() -> Int
 }
 
-sil hidden [thunk] [always_inline] [ossa] @foo_ : $@convention(witness_method:SomeProtocol) (@in_guaranteed SomeClass) -> Int {
+sil hidden [thunk] [heuristic_always_inline] [ossa] @foo_ : $@convention(witness_method:SomeProtocol) (@in_guaranteed SomeClass) -> Int {
 bb0(%0 : $*SomeClass):
   %1 = load_borrow %0 : $*SomeClass
   %2 = class_method %1 : $SomeClass, #SomeClass.foo : (SomeClass) -> () -> Int, $@convention(method) (@guaranteed SomeClass) -> Int
diff --git a/test/SILOptimizer/sil_combine_moveonly.sil b/test/SILOptimizer/sil_combine_moveonly.sil
index cdba9df1a353c..df42158c3c1d5 100644
--- a/test/SILOptimizer/sil_combine_moveonly.sil
+++ b/test/SILOptimizer/sil_combine_moveonly.sil
@@ -11,6 +11,11 @@ struct S : ~Copyable {
   deinit {}
 }
 
+struct S2 : ~Copyable {
+  @_hasStorage var a: Int { get set }
+  @_hasStorage var b: Int { get set }
+}
+
 struct FileDescriptor: ~Copyable {
   var fd: Builtin.Int64
 
@@ -31,6 +36,17 @@ struct Wrapper<T>: ~Copyable {
   var t: T
 }
 
+struct NonCopyableForwardingStruct : ~Copyable {
+  var some: Int
+  deinit
+}
+
+enum NonCopyableForwardingEnum : ~Copyable {
+  case some(Int)
+  case nothing
+  deinit
+}
+
 sil @getWrappedValue : $@convention(thin) <T> (@in_guaranteed Wrapper<T>) -> @out T
 
 // Test that a release_value is not removed for a struct-with-deinit.
@@ -110,3 +126,62 @@ bb0(%0 : @owned $S):
   %64 = tuple ()
   return %64 : $()
 }
+
+// Test a "dead" non-Copyable struct-with-deinit that forwards a
+// single trivial value. The destroy_value cannot be eliminated
+// without first devirtualizing the deinit.
+//
+// CHECK-LABEL: sil [ossa] @testNonCopyableForwardingStructDeinit : $@convention(thin) (Int) -> () {
+// CHECK: [[STRUCT:%[0-9]+]] = struct $NonCopyableForwardingStruct (%0 : $Int)
+// CHECK: destroy_value [[STRUCT]]
+// CHECK-LABEL: } // end sil function 'testNonCopyableForwardingStructDeinit'
+sil [ossa] @testNonCopyableForwardingStructDeinit : $@convention(thin) (Int) -> () {
+bb0(%0: $Int):
+  %1 = struct $NonCopyableForwardingStruct(%0 : $Int)
+  destroy_value %1
+  %13 = tuple ()
+  return %13
+}
+
+// Test a "dead" non-Copyable enum-with-deinit that forwards a single
+// trivial value. The destroy_value cannot be eliminated without first
+// devirtualizing the deinit.
+//
+// CHECK-LABEL: sil [ossa] @testNonCopyableForwardingEnumDeinit : $@convention(thin) (Int) -> () {
+// CHECK:   [[ENUM:%[0-9]+]] = enum $NonCopyableForwardingEnum, #NonCopyableForwardingEnum.some!enumelt, %0
+// CHECK:   destroy_value [[ENUM]]
+// CHECK-LABEL: } // end sil function 'testNonCopyableForwardingEnumDeinit'
+sil [ossa] @testNonCopyableForwardingEnumDeinit : $@convention(thin) (Int) -> () {
+bb0(%0 : $Int):
+  %1 = enum $NonCopyableForwardingEnum, #NonCopyableForwardingEnum.some!enumelt, %0
+  destroy_value %1
+  %13 = tuple ()
+  return %13
+}
+
+// Test a "dead" non-Copyable enum-with-deinit and an empty case. The
+// destroy_value cannot be eliminated without first devirtualizing the
+// deinit.
+//
+// CHECK-LABEL: sil [ossa] @testNonCopyableEmptyEnumDeinit : $@convention(thin) () -> () {
+// CHECK:   [[ENUM:%[0-9]+]] = enum $NonCopyableForwardingEnum, #NonCopyableForwardingEnum.nothing
+// CHECK:   destroy_value [[ENUM]]
+// CHECK-LABEL: } // end sil function 'testNonCopyableEmptyEnumDeinit'
+sil [ossa] @testNonCopyableEmptyEnumDeinit : $@convention(thin) () -> () {
+bb0:
+  %0 = enum $NonCopyableForwardingEnum, #NonCopyableForwardingEnum.nothing
+  destroy_value %0
+  %13 = tuple ()
+  return %13
+}
+
+// CHECK-LABEL: sil [ossa] @dont_remove_destructure_struct_of_non_copyable :
+// CHECK:         destructure_struct
+// CHECK-LABEL: } // end sil function 'dont_remove_destructure_struct_of_non_copyable'
+sil [ossa] @dont_remove_destructure_struct_of_non_copyable : $@convention(method) (@owned S2) -> () {
+bb0(%0 : @owned $S2):
+  (%1, %2) = destructure_struct %0
+  %r = tuple ()
+  return %r
+}
+
diff --git a/test/SILOptimizer/sil_combine_ossa.sil b/test/SILOptimizer/sil_combine_ossa.sil
index 036019da99326..4ff822fef292b 100644
--- a/test/SILOptimizer/sil_combine_ossa.sil
+++ b/test/SILOptimizer/sil_combine_ossa.sil
@@ -102,6 +102,14 @@ struct MoveOnlyStruct: ~Copyable {
   var value: MyInt
 }
 
+enum NoncopyableEnum : ~Copyable {
+case i(CopyableStruct)
+}
+
+struct CopyableStruct {
+  var guts: AnyObject
+}
+
 //////////////////////
 // Simple DCE Tests //
 //////////////////////
@@ -1596,18 +1604,6 @@ bb0(%0 : @guaranteed $B):
   return %3 : $F
 }
 
-// CHECK-LABEL: sil [ossa] @unchecked_ref_cast_formation_unowned : $@convention(thin) (B) -> F {
-// CHECK: bb0([[INPUT_REF:%[0-9]+]] :
-// CHECK: ref_to_raw_pointer
-// CHECK: raw_pointer_to_ref
-// CHECK: } // end sil function 'unchecked_ref_cast_formation_unowned'
-sil [ossa] @unchecked_ref_cast_formation_unowned : $@convention(thin) (B) -> F {
-bb0(%0 : @unowned $B):
-  %1 = ref_to_raw_pointer %0 : $B to $Builtin.RawPointer
-  %2 = raw_pointer_to_ref %1 : $Builtin.RawPointer to $F
-  return %2 : $F
-}
-
 // CHECK-LABEL: sil [ossa] @upcast_unchecked_ref_cast_roundtrip : $@convention(thin) (@owned B) -> @owned B {
 // CHECK-NOT: unchecked_ref_cast
 // CHECK-NOT: upcast
@@ -2737,27 +2733,6 @@ class XXImpl : XX {
   init()
 }
 
-// CHECK-LABEL: sil [ossa] @unowned_round_trips : $@convention(thin) (@guaranteed B, @guaranteed @sil_unowned B, @guaranteed AnyObject, @sil_unmanaged AnyObject) -> (B, @sil_unowned B, AnyObject, @sil_unmanaged AnyObject) {
-// CHECK: bb0(
-// CHECK-NEXT: tuple
-// CHECK-NEXT: return
-// CHECK: } // end sil function 'unowned_round_trips'
-sil [ossa] @unowned_round_trips : $@convention(thin) (@guaranteed B, @guaranteed @sil_unowned B, @guaranteed AnyObject, @sil_unmanaged AnyObject) -> (B, @sil_unowned B, AnyObject, @sil_unmanaged AnyObject) {
-bb0(%0 : @guaranteed $B, %1 : @guaranteed $@sil_unowned B, %2 : @guaranteed $AnyObject, %3 : $@sil_unmanaged AnyObject):
-  %4 = ref_to_unowned %0 : $B to $@sil_unowned B
-  %5 = unowned_to_ref %4 : $@sil_unowned B to $B
-  %6 = unowned_to_ref %1 : $@sil_unowned B to $B
-  %7 = ref_to_unowned %6 : $B to $@sil_unowned B
-
-  %8 = ref_to_unmanaged %2 : $AnyObject to $@sil_unmanaged AnyObject
-  %9 = unmanaged_to_ref %8 : $@sil_unmanaged AnyObject to $AnyObject
-  %10 = unmanaged_to_ref %3 : $@sil_unmanaged AnyObject to $AnyObject
-  %11 = ref_to_unmanaged %10 : $AnyObject to $@sil_unmanaged AnyObject
-
-  %9999 = tuple(%5 : $B, %7 : $@sil_unowned B, %9 : $AnyObject, %11 : $@sil_unmanaged AnyObject)
-  return %9999 : $(B, @sil_unowned B, AnyObject, @sil_unmanaged AnyObject)
-}
-
 // CHECK-LABEL: sil [ossa] @collapse_existential_pack_unpack_unchecked_ref_cast :
 // CHECK:       bb0([[Ref:%.*]] : @guaranteed $MyClass):
 // CHECK-NOT:     init_existential_ref
@@ -2959,7 +2934,6 @@ bb0(%0 : $Builtin.Int1):
 }
 
 // CHECK-LABEL: sil [ossa] @builtin_array_opt_index_raw_pointer_to_index_addr :
-// CHECK:  [[MT:%.*]] = metatype $@thick Int32.Type
 // CHECK:  [[ONE:%.*]] = integer_literal $Builtin.Word, 1
 // CHECK:  [[PTA1:%.*]] = pointer_to_address %1 : $Builtin.RawPointer to [strict] $*Int32
 // CHECK:  [[CAST1:%.*]] = builtin "truncOrBitCast_Int64_Word"(%0 : $Builtin.Int64)
@@ -2969,7 +2943,8 @@ bb0(%0 : $Builtin.Int1):
 // CHECK:  [[CAST2:%.*]] = builtin "truncOrBitCast_Int64_Word"(%0 : $Builtin.Int64)
 // CHECK:  [[IAD2:%.*]] = index_addr [[PTA2]] : $*Int32, [[CAST2]] : $Builtin.Word
 // CHECK:  [[ATP2:%.*]] = address_to_pointer [[IAD2]] : $*Int32 to $Builtin.RawPointer
-// CHECK:  builtin "takeArrayFrontToBack"<Int32>([[MT]] : $@thick Int32.Type, [[ATP1]] : $Builtin.RawPointer, [[ATP2]] : $Builtin.RawPointer, [[ONE]] : $Builtin.Word) : $()
+// CHECK:  [[MT:%.*]] = metatype $@thin Int32.Type
+// CHECK:  builtin "takeArrayFrontToBack"<Int32>([[MT]] : $@thin Int32.Type, [[ATP1]] : $Builtin.RawPointer, [[ATP2]] : $Builtin.RawPointer, [[ONE]] : $Builtin.Word) : $()
 // CHECK: return
 // CHECK: } // end sil function 'builtin_array_opt_index_raw_pointer_to_index_addr'
 
@@ -3337,11 +3312,9 @@ bb0(%0 : @owned $Builtin.NativeObject):
 
 // CHECK-LABEL: sil [ossa] @test_cmp_xor_canonicalization :
 // CHECK:bb0([[ARG:%.*]] : $Builtin.Int1
-// CHECK:  [[TRUE:%.*]] = integer_literal $Builtin.Int1, -1
 // CHECK:  [[FALSE:%.*]] = integer_literal $Builtin.Int1, 0
-// CHECK:  [[EQ:%.*]] = builtin "cmp_eq_Int1"([[ARG]] : $Builtin.Int1, [[FALSE]]
-// CHECK:  [[NOT:%.*]] = builtin "xor_Int1"([[EQ]] : $Builtin.Int1, [[TRUE]] : $Builtin.Int1)
-// CHECK:  return [[NOT]]
+// CHECK:  [[NE:%.*]] = builtin "cmp_ne_Int1"([[ARG]] : $Builtin.Int1, [[FALSE]]
+// CHECK:  return [[NE]]
 // CHECK: } // end sil function 'test_cmp_xor_canonicalization'
 sil [ossa] @test_cmp_xor_canonicalization : $@convention(thin) (Builtin.Int1) -> Builtin.Int1 {
 bb0(%0 : $Builtin.Int1):
@@ -5411,6 +5384,16 @@ bb1(%10 : @owned $Optional<@callee_guaranteed () -> ()>, %11 : @guaranteed $Opti
   return %12 : $()
 }
 
+// CHECK-LABEL: sil [ossa] @not_dead_mark_dependence_addr :
+// CHECK:         mark_dependence_addr %0 : $*B on %1
+// CHECK-LABEL: } // end sil function 'not_dead_mark_dependence_addr'
+sil [ossa] @not_dead_mark_dependence_addr : $@convention(thin) (@inout B, @in_guaranteed B) -> @owned B {
+bb0(%0 : $*B, %1 : $*B):
+  mark_dependence_addr %0 on %1
+  %3 = load [copy] %0
+  return %3
+}
+
 // CHECK-LABEL: sil [ossa] @remove_borrow_of_thin_function :
 // CHECK:         [[F:%.*]] = function_ref @unknown
 // CHECK:         [[T:%.*]] = thin_to_thick_function [[F]]
@@ -5498,3 +5481,66 @@ bb0(%1 : @owned $Cr):
   return %49
 }
 
+enum NT {
+  case inline(InlineArray<1, Int>)
+  case klass(Klass)
+}
+
+sil @get_inlinearray : $@convention(thin) () -> @out InlineArray<1, Int>
+
+// CHECK-LABEL: sil shared [ossa] @testTrivialPayloadInNonTrivialEnum :
+// CHECK-NOT: inject_enum_addr
+// CHECK-LABEL: } // end sil function 'testTrivialPayloadInNonTrivialEnum'
+sil shared [ossa] @testTrivialPayloadInNonTrivialEnum : $@convention(thin) () -> @owned NT {
+bb0:
+  %0 = alloc_stack $NT
+  %1 = init_enum_data_addr %0, #NT.inline!enumelt
+  %3 = function_ref @get_inlinearray : $@convention(thin) () -> @out InlineArray<1, Int>
+  %4 = apply %3(%1) : $@convention(thin) () -> @out InlineArray<1, Int>
+  inject_enum_addr %0, #NT.inline!enumelt
+  %6 = load [take] %0
+  dealloc_stack %0
+  return %6
+}
+
+// unchecked_take_enum_data_addr of a noncopyable base must not be combined if
+// there are any load [copy] users.
+// CHECK-LABEL: sil [ossa] @no_combine_uteda_load_copy_noncopyable {{.*}} {
+// CHECK:         unchecked_take_enum_data_addr
+// CHECK-LABEL: } // end sil function 'no_combine_uteda_load_copy_noncopyable'
+sil [ossa] @no_combine_uteda_load_copy_noncopyable : $@convention(thin) (@in NoncopyableEnum) -> () {
+entry(%e_addr : $*NoncopyableEnum):
+  %i_addr = unchecked_take_enum_data_addr %e_addr : $*NoncopyableEnum, #NoncopyableEnum.i!enumelt
+  %i_copy = load [copy] %i_addr : $*CopyableStruct
+  apply undef(%i_copy) : $@convention(thin) (@owned CopyableStruct) -> ()
+  %i = load [take] %i_addr : $*CopyableStruct
+  apply undef(%i) : $@convention(thin) (@owned CopyableStruct) -> ()
+  return undef : $()
+}
+
+// unchecked_take_enum_data_addr of a noncopyable base should be combined if
+// there are only load [take] users.
+// CHECK-LABEL: sil [ossa] @combine_uteda_load_take_noncopyable {{.*}} {
+// CHECK-NOT:     unchecked_take_enum_data_addr
+// CHECK-LABEL: } // end sil function 'combine_uteda_load_take_noncopyable'
+sil [ossa] @combine_uteda_load_take_noncopyable : $@convention(thin) (@in NoncopyableEnum) -> () {
+entry(%e_addr : $*NoncopyableEnum):
+  %i_addr = unchecked_take_enum_data_addr %e_addr : $*NoncopyableEnum, #NoncopyableEnum.i!enumelt
+  %i = load [take] %i_addr : $*CopyableStruct
+  apply undef(%i) : $@convention(thin) (@owned CopyableStruct) -> ()
+  return undef : $()
+}
+
+// unchecked_take_enum_data_addr of a noncopyable base should be combined if
+// there are only load_borrow users.
+// CHECK-LABEL: sil [ossa] @combine_uteda_load_borrow_noncopyable {{.*}} {
+// CHECK-NOT:     unchecked_take_enum_data_addr
+// CHECK-LABEL: } // end sil function 'combine_uteda_load_borrow_noncopyable'
+sil [ossa] @combine_uteda_load_borrow_noncopyable : $@convention(thin) (@in_guaranteed NoncopyableEnum) -> () {
+entry(%e_addr : $*NoncopyableEnum):
+  %i_addr = unchecked_take_enum_data_addr %e_addr : $*NoncopyableEnum, #NoncopyableEnum.i!enumelt
+  %i = load_borrow %i_addr : $*CopyableStruct
+  apply undef(%i) : $@convention(thin) (@guaranteed CopyableStruct) -> ()
+  end_borrow %i : $CopyableStruct
+  return undef : $()
+}
diff --git a/test/SILOptimizer/sil_combiner_concrete_prop_all_args.sil b/test/SILOptimizer/sil_combiner_concrete_prop_all_args.sil
index 5a8cb882e7b45..878d1e4795b14 100644
--- a/test/SILOptimizer/sil_combiner_concrete_prop_all_args.sil
+++ b/test/SILOptimizer/sil_combiner_concrete_prop_all_args.sil
@@ -128,7 +128,7 @@ bb0(%0 : $SomeClass):
   return %2 : $Int32                              
 } // end sil function '$s21existential_transform9SomeClassCAA0C8ProtocolA2aDP3foos5Int32VyFTW'
 
-sil hidden [signature_optimized_thunk] [always_inline] @$s21existential_transform11wrap_foo_cp1as5Int32VAA12SomeProtocol_p_tF : $@convention(thin) (@guaranteed SomeProtocol) -> Int32 {
+sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s21existential_transform11wrap_foo_cp1as5Int32VAA12SomeProtocol_p_tF : $@convention(thin) (@guaranteed SomeProtocol) -> Int32 {
 bb0(%0 : $SomeProtocol):
   %1 = function_ref @$s21existential_transform11wrap_foo_cp1as5Int32VAA12SomeProtocol_p_tFTf4e_n : $@convention(thin) <τ_0_0 where τ_0_0 : SomeProtocol> (@guaranteed τ_0_0) -> Int32 
   %2 = open_existential_ref %0 : $SomeProtocol to $@opened("CC97E160-AC7C-11E8-B742-D0817AD4059B", SomeProtocol) Self 
@@ -175,7 +175,7 @@ bb0(%0 : $*SomeNoClass):
   return %3 : $Int32                              
 } // end sil function '$s21existential_transform11SomeNoClassCAA0cdE8ProtocolA2aDP3foos5Int32VyFTW'
 
-sil hidden [signature_optimized_thunk] [always_inline] @$s21existential_transform12wrap_foo_ncp1as5Int32VAA19SomeNoClassProtocol_p_tF : $@convention(thin) (@in_guaranteed SomeNoClassProtocol) -> Int32 {
+sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s21existential_transform12wrap_foo_ncp1as5Int32VAA19SomeNoClassProtocol_p_tF : $@convention(thin) (@in_guaranteed SomeNoClassProtocol) -> Int32 {
 bb0(%0 : $*SomeNoClassProtocol):
   %1 = function_ref @$s21existential_transform12wrap_foo_ncp1as5Int32VAA19SomeNoClassProtocol_p_tFTf4e_n : $@convention(thin) <τ_0_0 where τ_0_0 : SomeNoClassProtocol> (@in_guaranteed τ_0_0) -> Int32 
   %2 = open_existential_addr immutable_access %0 : $*SomeNoClassProtocol to $*@opened("CC97FCD6-AC7C-11E8-B742-D0817AD4059B", SomeNoClassProtocol) Self 
@@ -237,7 +237,7 @@ bb0(%0 : $SomeClassComp):
   return %2 : $Int32                              
 } // end sil function '$s21existential_transform13SomeClassCompCAA0c5Otherd8ProtocolE0A2aDP3bars5Int32VyFTW'
 
-sil hidden [signature_optimized_thunk] [always_inline] @$s21existential_transform16wrap_foo_bar_cpc1as5Int32VAA21SomeClassProtocolComp_AA0h5OtherijK0p_tF : $@convention(thin) (@guaranteed SomeClassProtocolComp & SomeOtherClassProtocolComp) -> Int32 {
+sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s21existential_transform16wrap_foo_bar_cpc1as5Int32VAA21SomeClassProtocolComp_AA0h5OtherijK0p_tF : $@convention(thin) (@guaranteed SomeClassProtocolComp & SomeOtherClassProtocolComp) -> Int32 {
 bb0(%0 : $SomeClassProtocolComp & SomeOtherClassProtocolComp):
   %1 = function_ref @$s21existential_transform16wrap_foo_bar_cpc1as5Int32VAA21SomeClassProtocolComp_AA0h5OtherijK0p_tFTf4e_n : $@convention(thin) <τ_0_0 where τ_0_0 : SomeClassProtocolComp, τ_0_0 : SomeOtherClassProtocolComp> (@guaranteed τ_0_0) -> Int32 
   %2 = open_existential_ref %0 : $SomeClassProtocolComp & SomeOtherClassProtocolComp to $@opened("CC981856-AC7C-11E8-B742-D0817AD4059B", SomeClassProtocolComp & SomeOtherClassProtocolComp) Self
@@ -299,7 +299,7 @@ bb0(%0 : $*SomeNoClassComp):
   return %3 : $Int32                              
 } // end sil function '$s21existential_transform15SomeNoClassCompCAA0c5Otherde8ProtocolF0A2aDP3bars5Int32VyFTW'
 
-sil hidden [signature_optimized_thunk] [always_inline] @$s21existential_transform25wrap_no_foo_bar_comp_ncpc1as5Int32VAA23SomeNoClassProtocolComp_AA0j5OtherklmN0p_tF : $@convention(thin) (@in_guaranteed SomeNoClassProtocolComp & SomeOtherNoClassProtocolComp) -> Int32 {
+sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s21existential_transform25wrap_no_foo_bar_comp_ncpc1as5Int32VAA23SomeNoClassProtocolComp_AA0j5OtherklmN0p_tF : $@convention(thin) (@in_guaranteed SomeNoClassProtocolComp & SomeOtherNoClassProtocolComp) -> Int32 {
 bb0(%0 : $*SomeNoClassProtocolComp & SomeOtherNoClassProtocolComp):
   %1 = function_ref @$s21existential_transform25wrap_no_foo_bar_comp_ncpc1as5Int32VAA23SomeNoClassProtocolComp_AA0j5OtherklmN0p_tFTf4e_n : $@convention(thin) <τ_0_0 where τ_0_0 : SomeNoClassProtocolComp, τ_0_0 : SomeOtherNoClassProtocolComp> (@in_guaranteed τ_0_0) -> Int32 
   %2 = open_existential_addr immutable_access %0 : $*SomeNoClassProtocolComp & SomeOtherNoClassProtocolComp to $*@opened("CC983642-AC7C-11E8-B742-D0817AD4059B", SomeNoClassProtocolComp & SomeOtherNoClassProtocolComp) Self 
@@ -437,7 +437,7 @@ bb0(%0 : $*KKK):
   return %3 : $Int32                              
 } // end sil function '$s21existential_transform3KKKCAA3PPPA2aDP3foos5Int32VyFTW'
 
-sil hidden [signature_optimized_thunk] [always_inline] @$s21existential_transform14wrap_inout_ncp1as5Int32VAA3PPP_pz_tF : $@convention(thin) (@inout PPP) -> Int32 {
+sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s21existential_transform14wrap_inout_ncp1as5Int32VAA3PPP_pz_tF : $@convention(thin) (@inout PPP) -> Int32 {
 bb0(%0 : $*PPP):
   %1 = function_ref @$s21existential_transform14wrap_inout_ncp1as5Int32VAA3PPP_pz_tFTf4e_n : $@convention(thin) <τ_0_0 where τ_0_0 : PPP> (@inout τ_0_0) -> Int32 
   %2 = open_existential_addr mutable_access %0 : $*PPP to $*@opened("CC986BDA-AC7C-11E8-B742-D0817AD4059B", PPP) Self 
@@ -487,7 +487,7 @@ bb0(%0 : $*SSSS):
   return %2 : $Int32                              
 } // end sil function '$s21existential_transform4SSSSVAA4PPPPA2aDP3foos5Int32VyFTW'
 
-sil hidden [signature_optimized_thunk] [always_inline] @$s21existential_transform21wrap_struct_inout_ncp1as5Int32VAA4PPPP_pz_tF : $@convention(thin) (@inout PPPP) -> Int32 {
+sil hidden [signature_optimized_thunk] [heuristic_always_inline] @$s21existential_transform21wrap_struct_inout_ncp1as5Int32VAA4PPPP_pz_tF : $@convention(thin) (@inout PPPP) -> Int32 {
 bb0(%0 : $*PPPP):
   %1 = function_ref @$s21existential_transform21wrap_struct_inout_ncp1as5Int32VAA4PPPP_pz_tFTf4e_n : $@convention(thin) <τ_0_0 where τ_0_0 : PPPP> (@inout τ_0_0) -> Int32 
   %2 = open_existential_addr mutable_access %0 : $*PPPP to $*@opened("CC98A1E0-AC7C-11E8-B742-D0817AD4059B", PPPP) Self 
@@ -552,15 +552,9 @@ bb0(%0 : $*τ_0_0):
 
 // CHECK-LABEL: sil shared [noinline] @$s21existential_transform16wrap_foo_bar_cpc1as5Int32VAA21SomeClassProtocolComp_AA0h5OtherijK0p_tFTf4e_n4main0hiK0C_Tg5 : $@convention(thin) (@guaranteed SomeClassComp) -> Int32 {
 // CHECK: bb0(%0 : $SomeClassComp):
-// CHECK:  %1 = integer_literal $Builtin.Int32, 10         
-// CHECK:  %2 = integer_literal $Builtin.Int32, 20         
-// CHECK:  %3 = integer_literal $Builtin.Int1, -1          
-// CHECK:  %4 = builtin "sadd_with_overflow_Int32"(%1 : $Builtin.Int32, %2 : $Builtin.Int32, %3 : $Builtin.Int1) : $(Builtin.Int32, Builtin.Int1) 
-// CHECK:  %5 = tuple_extract %4 : $(Builtin.Int32, Builtin.Int1), 0 
-// CHECK:  %6 = tuple_extract %4 : $(Builtin.Int32, Builtin.Int1), 1 
-// CHECK:  cond_fail %6 : $Builtin.Int1                    
-// CHECK:  %8 = struct $Int32 (%5 : $Builtin.Int32)        
-// CHECK:  return %8 : $Int32                              
+// CHECK:  %1 = integer_literal $Builtin.Int32, 30         
+// CHECK:  %2 = struct $Int32 (%1 : $Builtin.Int32)        
+// CHECK:  return %2 : $Int32                              
 // CHECK: } // end sil function '$s21existential_transform16wrap_foo_bar_cpc1as5Int32VAA21SomeClassProtocolComp_AA0h5OtherijK0p_tFTf4e_n4main0hiK0C_Tg5'
 sil shared [noinline] @$s21existential_transform16wrap_foo_bar_cpc1as5Int32VAA21SomeClassProtocolComp_AA0h5OtherijK0p_tFTf4e_n : $@convention(thin) <τ_0_0 where τ_0_0 : SomeClassProtocolComp, τ_0_0 : SomeOtherClassProtocolComp> (@guaranteed τ_0_0) -> Int32 {
 bb0(%0 : $τ_0_0):
@@ -581,15 +575,9 @@ bb0(%0 : $τ_0_0):
 
 // CHECK-LABEL: sil shared [noinline] @$s21existential_transform25wrap_no_foo_bar_comp_ncpc1as5Int32VAA23SomeNoClassProtocolComp_AA0j5OtherklmN0p_tFTf4e_n4main0jklN0C_Tg5 : $@convention(thin) (@guaranteed SomeNoClassComp) -> Int32 {
 // CHECK: bb0(%0 : $SomeNoClassComp):
-// CHECK:   %1 = integer_literal $Builtin.Int32, 10         
-// CHECK:   %2 = integer_literal $Builtin.Int32, 20         
-// CHECK:   %3 = integer_literal $Builtin.Int1, -1          
-// CHECK:   %4 = builtin "sadd_with_overflow_Int32"(%1 : $Builtin.Int32, %2 : $Builtin.Int32, %3 : $Builtin.Int1) : $(Builtin.Int32, Builtin.Int1) 
-// CHECK:   %5 = tuple_extract %4 : $(Builtin.Int32, Builtin.Int1), 0 
-// CHECK:   %6 = tuple_extract %4 : $(Builtin.Int32, Builtin.Int1), 1 
-// CHECK:   cond_fail %6 : $Builtin.Int1                    
-// CHECK:   %8 = struct $Int32 (%5 : $Builtin.Int32)        
-// CHECK:   return %8 : $Int32                              
+// CHECK:   %1 = integer_literal $Builtin.Int32, 30
+// CHECK:   %2 = struct $Int32 (%1 : $Builtin.Int32)
+// CHECK:   return %2 : $Int32
 // CHECK-LABEL: } // end sil function '$s21existential_transform25wrap_no_foo_bar_comp_ncpc1as5Int32VAA23SomeNoClassProtocolComp_AA0j5OtherklmN0p_tFTf4e_n4main0jklN0C_Tg5'
 sil shared [noinline] @$s21existential_transform25wrap_no_foo_bar_comp_ncpc1as5Int32VAA23SomeNoClassProtocolComp_AA0j5OtherklmN0p_tFTf4e_n : $@convention(thin) <τ_0_0 where τ_0_0 : SomeNoClassProtocolComp, τ_0_0 : SomeOtherNoClassProtocolComp> (@in_guaranteed τ_0_0) -> Int32 {
 bb0(%0 : $*τ_0_0):
diff --git a/test/SILOptimizer/sil_verify_all_triggers_verifier_without_asserts.sil b/test/SILOptimizer/sil_verify_all_triggers_verifier_without_asserts.sil
index b57416ed0fce0..9219a75e49e2a 100644
--- a/test/SILOptimizer/sil_verify_all_triggers_verifier_without_asserts.sil
+++ b/test/SILOptimizer/sil_verify_all_triggers_verifier_without_asserts.sil
@@ -5,8 +5,6 @@
 
 // UNSUPPORTED: asserts
 
-// REQUIRES: rdar135847553
-
 class Klass {}
 
 sil [ossa] @leaky_code : $@convention(thin) () -> () {
diff --git a/test/SILOptimizer/simplify_alloc_stack.sil b/test/SILOptimizer/simplify_alloc_stack.sil
index 514f0f412d097..d1623d23cef60 100644
--- a/test/SILOptimizer/simplify_alloc_stack.sil
+++ b/test/SILOptimizer/simplify_alloc_stack.sil
@@ -10,11 +10,27 @@ public struct S {}
 protocol P {
 }
 
+protocol Q {
+  associatedtype A
+}
+
 public class C2: P {}
 
 public struct T: P {
   let c: C
   let s: S
+
+  struct A {
+    var y: String
+  }
+}
+
+public struct U: Q {
+  let s: String
+
+  struct A {
+    var y: String
+  }
 }
 
 public struct T1: P {
@@ -41,7 +57,7 @@ sil [ossa] @use_mp : $@convention(thin) (@in_guaranteed MP) -> ()
 sil [ossa] @use_c2 : $@convention(thin) (@in_guaranteed C2) -> ()
 
 // CHECK-LABEL: sil [ossa] @expand_alloc_stack_of_enum1 :
-// CHECK:        [[A:%[0-9]+]] = alloc_stack $S
+// CHECK:        [[A:%[0-9]+]] = alloc_stack [lexical] $S
 // CHECK:      bb1:
 // CHECK-NEXT:   store %0 to [trivial] [[A]]
 // CHECK:      bb2:
@@ -51,7 +67,7 @@ sil [ossa] @use_c2 : $@convention(thin) (@in_guaranteed C2) -> ()
 // CHECK:      } // end sil function 'expand_alloc_stack_of_enum1'
 sil [ossa] @expand_alloc_stack_of_enum1 : $@convention(method) (S) -> () {
 bb0(%0 : $S):
-  %1 = alloc_stack $MP
+  %1 = alloc_stack [lexical] $MP
   cond_br undef, bb1, bb2
 
 bb1:
@@ -215,7 +231,7 @@ bb0(%0 : $S):
 }
 
 // CHECK-LABEL: sil [ossa] @replace_archetype :
-// CHECK:         [[S:%.*]] = alloc_stack $T
+// CHECK:         [[S:%.*]] = alloc_stack [lexical] $T
 // CHECK:         debug_value [[S]]
 // CHECK:         unchecked_addr_cast [[S]]
 // CHECK:         destroy_addr [[S]]
@@ -225,7 +241,7 @@ bb0(%0 : @owned $T):
   %1 = metatype $@thick T.Type
   %2 = init_existential_metatype %1, $@thick P.Type
   %3 = open_existential_metatype %2 to $@thick (@opened("82105EE0-DCB0-11E5-865D-C8E0EB309913", P) Self).Type
-  %4 = alloc_stack $@opened("82105EE0-DCB0-11E5-865D-C8E0EB309913", P) Self
+  %4 = alloc_stack [lexical] $@opened("82105EE0-DCB0-11E5-865D-C8E0EB309913", P) Self
   debug_value %4, var, name "x"
   %5 = unchecked_addr_cast %4 to $*T
   store %0 to [init] %5
@@ -235,6 +251,24 @@ bb0(%0 : @owned $T):
   return %r
 }
 
+// TODO: we don't support dependent existential archetypes, yet. Once we do, change this test case.
+// CHECK-LABEL: sil [ossa] @dont_replace_dependent_archetype :
+// CHECK:         alloc_stack {{.*}}@opened
+// CHECK:       } // end sil function 'dont_replace_dependent_archetype'
+sil [ossa] @dont_replace_dependent_archetype : $@convention(thin) (@owned U.A) -> () {
+bb0(%0 : @owned $U.A):
+  %1 = metatype $@thick U.Type
+  %2 = init_existential_metatype %1, $@thick Q.Type
+  %3 = open_existential_metatype %2 to $@thick (@opened("82105EE0-DCB0-11E5-865D-C8E0EB309914", Q) Self).Type
+  %4 = alloc_stack $(@opened("82105EE0-DCB0-11E5-865D-C8E0EB309914", Q) Self).A
+  %5 = unchecked_addr_cast %4 to $*U.A
+  store %0 to [init] %5
+  destroy_addr %4
+  dealloc_stack %4
+  %r = tuple ()
+  return %r
+}
+
 // CHECK-LABEL: sil [ossa] @replace_existential_with_concrete_type1 :
 // CHECK:         [[S:%.*]] = alloc_stack $T
 // CHECK-NOT:     init_existential_addr
@@ -365,3 +399,19 @@ bb0(%0 : @owned $C2):
   dealloc_stack %1
   return %5
 }
+
+// CHECK-LABEL: sil [ossa] @dont_replace_existential_with_escaping_addr :
+// CHECK:         alloc_stack $any P
+// CHECK:       } // end sil function 'dont_replace_existential_with_escaping_addr'
+sil [ossa] @dont_replace_existential_with_escaping_addr : $@convention(thin) <V> (@thick V.Type, @owned C2) -> @out V {
+bb0(%0 : $*V, %1 : $@thick V.Type, %2 : @owned $C2):
+  %114 = alloc_stack $any P
+  %117 = init_existential_addr %114, $C2
+  store %2 to [init] %117
+  %129 = unchecked_addr_cast %114 to $*V
+  copy_addr %129 to [init] %0
+  destroy_addr %114
+  dealloc_stack %114
+  %137 = tuple ()
+  return %137
+}
diff --git a/test/SILOptimizer/simplify_apply.sil b/test/SILOptimizer/simplify_apply.sil
index 0e4614ee83a0a..fb123080fc4ec 100644
--- a/test/SILOptimizer/simplify_apply.sil
+++ b/test/SILOptimizer/simplify_apply.sil
@@ -26,6 +26,25 @@ struct GenS<T> {
   var x: Int
 }
 
+enum E: String {
+  case a, b, c, d, e
+}
+
+protocol P2 {
+  associatedtype A: Q
+}
+
+protocol Q {
+}
+
+public struct S2: P2 {
+  var x: String
+  struct A: Q {
+    var y: String
+  }
+}
+
+
 sil @cl : $@convention(thin) () -> Int
 
 // CHECK-LABEL: sil [ossa] @thick_to_thin :
@@ -60,6 +79,7 @@ sil_vtable Bar {
 }
 
 sil @createit : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@thick τ_0_0.Type, Int) -> @out τ_0_0
+sil @create2 : $@convention(thin) <τ_0_0 where τ_0_0 : Q> (Int) -> @out τ_0_0
 sil @useGenS : $@convention(thin) <τ_0_0 where τ_0_0 : P> (GenS<τ_0_0>) -> ()
 sil @returnGenS : $@convention(thin) <τ_0_0 where τ_0_0 : P> (@thick τ_0_0.Type) -> GenS<τ_0_0>
 
@@ -124,6 +144,22 @@ bb0(%0 : $Int):
   return %11
 }
 
+// TODO: we don't support dependent existential archetypes, yet. Once we do, change this test case.
+// CHECK-LABEL: sil [ossa] @dont_replace_dependent_archetype :
+// CHECK:         apply %{{[0-9]+}}<(@opened
+// CHECK:       } // end sil function 'dont_replace_dependent_archetype'
+sil [ossa] @dont_replace_dependent_archetype : $@convention(thin) (Int) -> @out any Q {
+bb0(%0 : $*any Q, %1 : $Int):
+  %2 = metatype $@thick S2.Type
+  %3 = init_existential_metatype %2, $@thick any P2.Type
+  %4 = open_existential_metatype %3 to $@thick (@opened("0FC03D78-E9DB-11EF-B47C-0EA13E3AABB4", any P2) Self).Type
+  %6 = function_ref @create2 : $@convention(thin) <τ_0_0 where τ_0_0 : Q> (Int) -> @out τ_0_0
+  %7 = init_existential_addr %0, $(@opened("0FC03D78-E9DB-11EF-B47C-0EA13E3AABB4", any P2) Self).A
+  %8 = apply %6<(@opened("0FC03D78-E9DB-11EF-B47C-0EA13E3AABB4", any P2) Self).A>(%7, %1) : $@convention(thin) <τ_0_0 where τ_0_0 : Q> (Int) -> @out τ_0_0
+  %11 = tuple ()
+  return %11
+}
+
 // CHECK-LABEL: sil [ossa] @dont_replace_returned_embedded_archetype :
 // CHECK:         apply %{{[0-9]+}}<@opened
 // CHECK:       } // end sil function 'dont_replace_returned_embedded_archetype'
@@ -165,3 +201,31 @@ bb0(%0 : @guaranteed $Array<Any>):
   return %2
 }
 
+sil [_semantics "rawrepresentable.is_equal"] @rawrepresentable_is_equal : $@convention(thin) <T where T : RawRepresentable, T.RawValue : Equatable> (@in_guaranteed T, @in_guaranteed T) -> Bool
+sil [_semantics "rawrepresentable.is_equal"] @rawrepresentable_is_equal_wrong_convention : $@convention(thin) (E, E) -> Bool
+
+// CHECK-LABEL: sil [ossa] @string_enum_is_equal :
+// CHECK:         %2 = builtin "getEnumTag"<E>(%0) : $Builtin.Int32
+// CHECK:         %3 = builtin "getEnumTag"<E>(%1) : $Builtin.Int32
+// CHECK:         %4 = builtin "cmp_eq_Int32"(%2, %3) : $Builtin.Int1
+// CHECK:         %5 = struct $Bool (%4)
+// CHECK:         return %5
+// CHECK:       } // end sil function 'string_enum_is_equal'
+sil [ossa] @string_enum_is_equal : $@convention(thin) (@in_guaranteed E, @in_guaranteed E) -> Bool {
+bb0(%0 : $*E, %1 : $*E):
+  %2 = function_ref @rawrepresentable_is_equal : $@convention(thin) <T where T : RawRepresentable, T.RawValue : Equatable> (@in_guaranteed T, @in_guaranteed T) -> Bool
+  %3 = apply %2<E>(%0, %1) : $@convention(thin) <τ_0_0 where τ_0_0 : RawRepresentable, τ_0_0.RawValue : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0) -> Bool
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @string_enum_is_equal_wrong_convention :
+// CHECK:         function_ref
+// CHECK:         apply
+// CHECK:       } // end sil function 'string_enum_is_equal_wrong_convention'
+sil [ossa] @string_enum_is_equal_wrong_convention : $@convention(thin) (E, E) -> Bool {
+bb0(%0 : $E, %1 : $E):
+  %2 = function_ref @rawrepresentable_is_equal_wrong_convention : $@convention(thin) (E, E) -> Bool
+  %3 = apply %2(%0, %1) : $@convention(thin) (E, E) -> Bool
+  return %3
+}
+
diff --git a/test/SILOptimizer/simplify_builtin.sil b/test/SILOptimizer/simplify_builtin.sil
index c14f349629cef..5aa7398f302b6 100644
--- a/test/SILOptimizer/simplify_builtin.sil
+++ b/test/SILOptimizer/simplify_builtin.sil
@@ -694,3 +694,166 @@ bb0:
   return %0
 }
 
+// CHECK-LABEL: sil @invert_comparison_eq :
+// CHECK:         %2 = builtin "cmp_ne_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_eq'
+sil @invert_comparison_eq : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_eq_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @invert_comparison_ne :
+// CHECK:         %2 = builtin "cmp_eq_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_ne'
+sil @invert_comparison_ne : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_ne_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @invert_comparison_sle :
+// CHECK:         %2 = builtin "cmp_sgt_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_sle'
+sil @invert_comparison_sle : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_sle_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @invert_comparison_slt :
+// CHECK:         %2 = builtin "cmp_sge_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_slt'
+sil @invert_comparison_slt : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_slt_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @invert_comparison_sge :
+// CHECK:         %2 = builtin "cmp_slt_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_sge'
+sil @invert_comparison_sge : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_sge_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @invert_comparison_sgt :
+// CHECK:         %2 = builtin "cmp_sle_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_sgt'
+sil @invert_comparison_sgt : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_sgt_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @invert_comparison_ule :
+// CHECK:         %2 = builtin "cmp_ugt_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_ule'
+sil @invert_comparison_ule : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_ule_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @invert_comparison_ult :
+// CHECK:         %2 = builtin "cmp_uge_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_ult'
+sil @invert_comparison_ult : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_ult_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @invert_comparison_uge :
+// CHECK:         %2 = builtin "cmp_ult_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_uge'
+sil @invert_comparison_uge : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_uge_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @invert_comparison_ugt :
+// CHECK:         %2 = builtin "cmp_ule_Int64"(%0 : $Builtin.Int64, %1 : $Builtin.Int64)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'invert_comparison_ugt'
+sil @invert_comparison_ugt : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_ugt_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @no_invert_wrong_literal :
+// CHECK:         builtin "cmp_ugt_Int64"
+// CHECK:       } // end sil function 'no_invert_wrong_literal'
+sil @no_invert_wrong_literal : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64):
+  %2 = builtin "cmp_ugt_Int64"(%0, %1) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, 0
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @no_invert_unknown_rhs :
+// CHECK:         builtin "cmp_ugt_Int64"
+// CHECK:       } // end sil function 'no_invert_unknown_rhs'
+sil @no_invert_unknown_rhs : $@convention(thin) (Builtin.Int64, Builtin.Int64, Builtin.Int1) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int64, %1 : $Builtin.Int64, %2 : $Builtin.Int1):
+  %3 = builtin "cmp_ugt_Int64"(%0, %1) : $Builtin.Int1
+  %4 = builtin "xor_Int1"(%3, %2) : $Builtin.Int1
+  return %4
+}
+
+// CHECK-LABEL: sil @no_invert_no_comparison :
+// CHECK:         %2 = builtin "xor_Int1"
+// CHECK:         return %2
+// CHECK:       } // end sil function 'no_invert_no_comparison'
+sil @no_invert_no_comparison : $@convention(thin) (Builtin.Int1) -> Builtin.Int1 {
+bb0(%0 : $Builtin.Int1):
+  %1 = integer_literal $Builtin.Int1, -1
+  %2 = builtin "xor_Int1"(%0, %1) : $Builtin.Int1
+  return %2
+}
+
+// CHECK-LABEL: sil @no_invert_wrong_comparison :
+// CHECK:         builtin "fcmp_ord_FPIEEE32"
+// CHECK:       } // end sil function 'no_invert_wrong_comparison'
+sil @no_invert_wrong_comparison : $@convention(thin) (Builtin.FPIEEE32, Builtin.FPIEEE32) -> Builtin.Int1 {
+bb0(%0 : $Builtin.FPIEEE32, %1 : $Builtin.FPIEEE32):
+  %2 = builtin "fcmp_ord_FPIEEE32"(%0 : $Builtin.FPIEEE32, %1 : $Builtin.FPIEEE32) : $Builtin.Int1
+  %3 = integer_literal $Builtin.Int1, -1
+  %4 = builtin "xor_Int1"(%2, %3) : $Builtin.Int1
+  return %4
+}
+
diff --git a/test/SILOptimizer/simplify_cfg_checkcast.sil b/test/SILOptimizer/simplify_cfg_checkcast.sil
index 35894aeb33931..24c226755c9e0 100644
--- a/test/SILOptimizer/simplify_cfg_checkcast.sil
+++ b/test/SILOptimizer/simplify_cfg_checkcast.sil
@@ -539,7 +539,7 @@ bb7:
 // Simplify down to a single diamond.
 //
 // TODO: Simplify some of the obviously dead copy/destroy/borrows
-// on-the-fly after each simplify-cfg. Possible using CanonicalizeOSSALifetime.
+// on-the-fly after each simplify-cfg. Possible using OSSACanonicalizeOwned.
 //
 // TODO-CHECK-LABEL: sil [ossa] @redundant_checked_cast_br_rauw_guaranteed_to_owned_merge : $@convention(method) (@owned Base) -> () {
 // TODO-CHECK: bb0(%0 : @owned $Base):
diff --git a/test/SILOptimizer/simplify_cfg_crash.swift b/test/SILOptimizer/simplify_cfg_crash.swift
index 5410b986f620d..8deab7259639e 100644
--- a/test/SILOptimizer/simplify_cfg_crash.swift
+++ b/test/SILOptimizer/simplify_cfg_crash.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -O %s -enable-ossa-modules -emit-sil -o /dev/null
+// RUN: %target-swift-frontend -O %s -emit-sil -o /dev/null
 
 public class X {}
 
diff --git a/test/SILOptimizer/simplify_copy_block.sil b/test/SILOptimizer/simplify_copy_block.sil
new file mode 100644
index 0000000000000..ee686659af87f
--- /dev/null
+++ b/test/SILOptimizer/simplify_copy_block.sil
@@ -0,0 +1,172 @@
+// RUN: %target-sil-opt %s -simplification -simplify-instruction=copy_block | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+sil_stage canonical
+
+import Swift
+import SwiftShims
+import Builtin
+
+// CHECK-LABEL: sil [ossa] @remove_copy_block :
+// CHECK-NOT:     copy_block
+// CHECK:         apply %0
+// CHECK-NOT:     destroy_value
+// CHECK:       } // end sil function 'remove_copy_block'
+sil [ossa] @remove_copy_block : $@convention(thin) (@convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @unowned $@convention(block) @noescape () -> ()):
+  %2 = copy_block %0
+  %3 = begin_borrow [lexical] %2
+  %4 = apply %3() : $@convention(block) @noescape () -> ()
+  end_borrow %3
+  destroy_value %2
+  %7 = tuple ()
+  return %7
+}
+
+// CHECK-LABEL: sil [ossa] @remove_copy_block_with_partial_apply :
+// CHECK-NOT:     copy_block
+// CHECK:         [[B:%.*]] = unchecked_ownership_conversion %0, @unowned to @guaranteed
+// CHECK:         [[PA:%.*]] = partial_apply [callee_guaranteed] [on_stack] {{%[0-9]+}}([[B]])
+// CHECK:         destroy_value [[PA]]
+// CHECK-NOT:     destroy_value
+// CHECK:       } // end sil function 'remove_copy_block_with_partial_apply'
+sil [ossa] @remove_copy_block_with_partial_apply : $@convention(thin) (@convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @unowned $@convention(block) @noescape () -> ()):
+  %2 = copy_block %0
+  %3 = function_ref @thunk : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  %4 = partial_apply [callee_guaranteed] [on_stack] %3(%2) : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  destroy_value %4
+  destroy_value %2
+  %7 = tuple ()
+  return %7
+}
+
+// CHECK-LABEL: sil [ossa] @remove_copy_block_with_partial_apply_guaranteed :
+// CHECK-NOT:     copy_block
+// CHECK:         [[PA:%.*]] = partial_apply [callee_guaranteed] [on_stack] {{%[0-9]+}}(%0)
+// CHECK:         destroy_value [[PA]]
+// CHECK-NOT:     destroy_value
+// CHECK:       } // end sil function 'remove_copy_block_with_partial_apply_guaranteed'
+sil [ossa] @remove_copy_block_with_partial_apply_guaranteed : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @guaranteed $@convention(block) @noescape () -> ()):
+  %2 = copy_block %0
+  %3 = function_ref @thunk : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  %4 = partial_apply [callee_guaranteed] [on_stack] %3(%2) : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  destroy_value %4
+  destroy_value %2
+  %7 = tuple ()
+  return %7
+}
+
+// CHECK-LABEL: sil [ossa] @remove_copy_block_with_partial_apply_owned :
+// CHECK-NOT:     copy_block
+// CHECK:         [[PA:%.*]] = partial_apply [callee_guaranteed] [on_stack] {{%[0-9]+}}(%0)
+// CHECK:       } // end sil function 'remove_copy_block_with_partial_apply_owned'
+sil [ossa] @remove_copy_block_with_partial_apply_owned : $@convention(thin) (@owned @convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @owned $@convention(block) @noescape () -> ()):
+  %2 = copy_block %0
+  %3 = function_ref @thunk : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  %4 = partial_apply [callee_guaranteed] [on_stack] %3(%2) : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  destroy_value %4
+  destroy_value %2
+  destroy_value %0
+  %7 = tuple ()
+  return %7
+}
+
+sil [ossa] @thunk : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @guaranteed $@convention(block) @noescape () -> ()):
+  %1 = apply %0() : $@convention(block) @noescape () -> ()
+  %2 = tuple ()
+  return %2
+}
+
+sil @use_closure : $@convention(thin) (@guaranteed @callee_guaranteed () -> ()) -> ()
+
+// CHECK-LABEL: sil [ossa] @dont_remove_copy_block_with_escaping_partial_apply :
+// CHECK:         copy_block
+// CHECK:       } // end sil function 'dont_remove_copy_block_with_escaping_partial_apply'
+sil [ossa] @dont_remove_copy_block_with_escaping_partial_apply : $@convention(thin) (@convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @unowned $@convention(block) @noescape () -> ()):
+  %2 = copy_block %0
+  %3 = function_ref @thunk : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  %4 = partial_apply [callee_guaranteed] %3(%2) : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  %5 = function_ref @use_closure : $@convention(thin) (@guaranteed @callee_guaranteed () -> ()) -> ()
+  apply %5(%4) : $@convention(thin) (@guaranteed @callee_guaranteed () -> ()) -> ()
+  destroy_value %4
+  %7 = tuple ()
+  return %7
+}
+
+sil [ossa] @unknown_thunk : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+
+// CHECK-LABEL: sil [ossa] @dont_remove_copy_block_with_unknown_partial_apply :
+// CHECK:         copy_block
+// CHECK:       } // end sil function 'dont_remove_copy_block_with_unknown_partial_apply'
+sil [ossa] @dont_remove_copy_block_with_unknown_partial_apply : $@convention(thin) (@convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @unowned $@convention(block) @noescape () -> ()):
+  %2 = copy_block %0
+  %3 = function_ref @unknown_thunk : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  %4 = partial_apply [callee_guaranteed] [on_stack] %3(%2) : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  destroy_value %4
+  destroy_value %2
+  %7 = tuple ()
+  return %7
+}
+
+// CHECK-LABEL: sil [ossa] @dont_remove_copy_block_with_partial_apply_escaping :
+// CHECK:         copy_block
+// CHECK:       } // end sil function 'dont_remove_copy_block_with_partial_apply_escaping'
+sil [ossa] @dont_remove_copy_block_with_partial_apply_escaping : $@convention(thin) (@convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @unowned $@convention(block) @noescape () -> ()):
+  %2 = copy_block %0
+  %3 = function_ref @thunk_escaping : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  %4 = partial_apply [callee_guaranteed] [on_stack] %3(%2) : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> ()
+  destroy_value %4
+  destroy_value %2
+  %7 = tuple ()
+  return %7
+}
+
+sil [ossa] @thunk_escaping : $@convention(thin) (@guaranteed @convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @guaranteed $@convention(block) @noescape () -> ()):
+  %1 = function_ref @use_block : $@convention(thin) (@convention(block) @noescape () -> ()) -> ()
+  %2 = apply %1(%0) : $@convention(thin) (@convention(block) @noescape () -> ()) -> ()
+  %3 = tuple ()
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @dont_remove_copied_block :
+// CHECK:         copy_block
+// CHECK:       } // end sil function 'dont_remove_copied_block'
+sil [ossa] @dont_remove_copied_block : $@convention(thin) (@convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @unowned $@convention(block) @noescape () -> ()):
+  %2 = copy_block %0
+  %3 = begin_borrow [lexical] %2
+  %4 = apply %3() : $@convention(block) @noescape () -> ()
+  %5 = copy_value %3
+  fix_lifetime %5
+  destroy_value %5
+  end_borrow %3
+  destroy_value %2
+  %7 = tuple ()
+  return %7
+}
+
+sil [ossa] @use_block : $@convention(thin) (@convention(block) @noescape () -> ()) -> ()
+
+// CHECK-LABEL: sil [ossa] @dont_remove_escaping_block :
+// CHECK:         copy_block
+// CHECK:       } // end sil function 'dont_remove_escaping_block'
+sil [ossa] @dont_remove_escaping_block : $@convention(thin) (@convention(block) @noescape () -> ()) -> () {
+bb0(%0 : @unowned $@convention(block) @noescape () -> ()):
+  %2 = copy_block %0
+  %3 = begin_borrow [lexical] %2
+  %4 = function_ref @use_block : $@convention(thin) (@convention(block) @noescape () -> ()) -> ()
+  %5 = apply %4(%3) : $@convention(thin) (@convention(block) @noescape () -> ()) -> ()
+  end_borrow %3
+  destroy_value %2
+  %7 = tuple ()
+  return %7
+}
diff --git a/test/SILOptimizer/simplify_end_cow_mutation_addr.sil b/test/SILOptimizer/simplify_end_cow_mutation_addr.sil
new file mode 100644
index 0000000000000..6b0f8a88a7e6b
--- /dev/null
+++ b/test/SILOptimizer/simplify_end_cow_mutation_addr.sil
@@ -0,0 +1,45 @@
+// RUN: %target-sil-opt %s -onone-simplification -simplify-instruction=end_cow_mutation_addr -enable-experimental-feature Lifetimes | %FileCheck %s
+
+// REQUIRES: swift_feature_Lifetimes
+
+import Swift
+import Builtin
+
+protocol P {
+  mutating func getMutableSpan() -> MutableSpan<Int>
+}
+
+struct C : P {
+  @_hasStorage var array: [Int] { get set }
+  mutating func getMutableSpan() -> MutableSpan<Int>
+  init(array: [Int])
+}
+
+extension Array : P where Element == Int {
+  mutating func getMutableSpan() -> MutableSpan<Int>
+}
+
+sil @getMutableSpan : $@convention(method) (@inout Array<Int>) -> @lifetime(borrow 0) @owned MutableSpan<Int>
+sil @write : $@convention(thin) (@lifetime(copy 0) @inout MutableSpan<Int>) -> ()
+
+// CHECK-LABEL: sil hidden @test_end_cow_mutation_addr :
+// CHECK-NOT: end_cow_mutation_addr
+// CHECK: end_cow_mutation
+// CHECK:       } // end sil function 'test_end_cow_mutation_addr'
+sil hidden @test_end_cow_mutation_addr : $@convention(thin) (@inout C) -> () {
+bb0(%0 : $*C):
+  %3 = alloc_stack [lexical] [var_decl] $MutableSpan<Int>, var, name "span"
+  %5 = struct_element_addr %0, #C.array
+  %6 = function_ref @getMutableSpan : $@convention(method) (@inout Array<Int>) -> @lifetime(borrow 0) @owned MutableSpan<Int>
+  %7 = apply %6(%5) : $@convention(method) (@inout Array<Int>) -> @lifetime(borrow 0) @owned MutableSpan<Int>
+  %8 = mark_dependence [nonescaping] %7 on %0
+  %9 = mark_dependence [nonescaping] %8 on %0
+  %10 = mark_dependence [nonescaping] %9 on %0
+  store %10 to %3
+  %12 = function_ref @write : $@convention(thin) (@lifetime(copy 0) @inout MutableSpan<Int>) -> ()
+  %13 = apply %12(%3) : $@convention(thin) (@lifetime(copy 0) @inout MutableSpan<Int>) -> ()
+  end_cow_mutation_addr %0
+  dealloc_stack %3
+  %17 = tuple ()
+  return %17
+}
diff --git a/test/SILOptimizer/simplify_explicit_copy_addr.sil b/test/SILOptimizer/simplify_explicit_copy_addr.sil
new file mode 100644
index 0000000000000..af80a70ab455a
--- /dev/null
+++ b/test/SILOptimizer/simplify_explicit_copy_addr.sil
@@ -0,0 +1,38 @@
+// RUN: %target-sil-opt -enable-sil-verify-all %s -onone-simplification -simplify-instruction=explicit_copy_addr | %FileCheck %s --check-prefix=CHECK-ONONE --check-prefix=CHECK
+// RUN: %target-sil-opt -enable-sil-verify-all %s -simplification -simplify-instruction=explicit_copy_addr | %FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK
+
+// REQUIRES: swift_in_compiler
+
+sil_stage canonical
+
+import Swift
+import Builtin
+
+// CHECK-LABEL:      sil [ossa] @simplify_copy_take_init :
+// CHECK:            bb0(%0 : $*String, %1 : $*String):
+// CHECK-O-NEXT:       {{ }}copy_addr [take] %1 to [init] %0
+// CHECK-ONONE-NEXT:   explicit_copy_addr [take] %1 to [init] %0
+// CHECK-NEXT:         %3 = tuple ()
+// CHECK:            } // end sil function 'simplify_copy_take_init'
+sil [ossa] @simplify_copy_take_init : $@convention(thin) (@in String) -> @out String {
+bb0(%0 : $*String, %1 : $*String):
+  explicit_copy_addr [take] %1 to [init] %0
+  %3 = tuple ()
+  return %3
+}
+
+// CHECK-LABEL:      sil [ossa] @simplify_copy_assign :
+// CHECK:            bb0(%0 : $*String, %1 : $*String):
+// CHECK-O-NEXT:       {{ }}copy_addr %1 to %0
+// CHECK-ONONE-NEXT:   explicit_copy_addr %1 to %0
+// CHECK-NEXT:         %3 = tuple ()
+// CHECK:            } // end sil function 'simplify_copy_assign'
+sil [ossa] @simplify_copy_assign : $@convention(thin) (@inout String, @inout String) -> () {
+bb0(%0 : $*String, %1 : $*String):
+  explicit_copy_addr %1 to %0
+  %3 = tuple ()
+  return %3
+}
+
+
+
diff --git a/test/SILOptimizer/simplify_explicit_copy_value.sil b/test/SILOptimizer/simplify_explicit_copy_value.sil
new file mode 100644
index 0000000000000..e8edea597093d
--- /dev/null
+++ b/test/SILOptimizer/simplify_explicit_copy_value.sil
@@ -0,0 +1,21 @@
+// RUN: %target-sil-opt -enable-sil-verify-all %s -onone-simplification -simplify-instruction=explicit_copy_value | %FileCheck %s --check-prefix=CHECK-ONONE --check-prefix=CHECK
+// RUN: %target-sil-opt -enable-sil-verify-all %s -simplification -simplify-instruction=explicit_copy_value | %FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK
+
+// REQUIRES: swift_in_compiler
+
+sil_stage canonical
+
+import Swift
+import Builtin
+
+// CHECK-LABEL: sil [ossa] @simplify_explicit_copy_value :
+// CHECK-O:       %1 = copy_value %0
+// CHECK-ONONE:   %1 = explicit_copy_value %0
+// CHECK-NEXT:    return %1
+// CHECK:       } // end sil function 'simplify_explicit_copy_value'
+sil [ossa] @simplify_explicit_copy_value : $@convention(thin) (@guaranteed String) -> @owned String {
+bb0(%0 : @guaranteed $String):
+  %1 = explicit_copy_value %0
+  return %1
+}
+
diff --git a/test/SILOptimizer/simplify_load_borrow.sil b/test/SILOptimizer/simplify_load_borrow.sil
index ee979fc70ad5c..abb80f3cc8445 100644
--- a/test/SILOptimizer/simplify_load_borrow.sil
+++ b/test/SILOptimizer/simplify_load_borrow.sil
@@ -17,7 +17,7 @@ class E : B {
 // CHECK:         end_borrow %2
 // CHECK:         destroy_value %1 
 // CHECK:         return %4
-// CHEKCK       } // end sil function '@load_borrow_and_copy'
+// CHECK:       } // end sil function 'load_borrow_and_copy'
 sil [ossa] @load_borrow_and_copy : $@convention(thin) (@inout E) -> Int {
 bb0(%0 : $*E):
   %1 = load_borrow %0
@@ -40,7 +40,7 @@ bb0(%0 : $*E):
 // CHECK:         end_borrow %3
 // CHECK:         destroy_value %2 
 // CHECK:         return %5
-// CHEKCK       } // end sil function '@load_borrow_and_copy_forwarding'
+// CHECK:       } // end sil function 'load_borrow_and_copy_forwarding'
 sil [ossa] @load_borrow_and_copy_forwarding : $@convention(thin) (@inout B) -> Int {
 bb0(%0 : $*B):
   %1 = load_borrow %0
@@ -58,7 +58,7 @@ bb0(%0 : $*B):
 // CHECK-LABEL: sil [ossa] @load_borrow_and_copy_different_block :
 // CHECK:         %1 = load_borrow %0
 // CHECK:         %3 = copy_value %1
-// CHEKCK       } // end sil function '@load_borrow_and_copy_different_block'
+// CHECK:       } // end sil function 'load_borrow_and_copy_different_block'
 sil [ossa] @load_borrow_and_copy_different_block : $@convention(thin) (@inout E) -> () {
 bb0(%0 : $*E):
   %1 = load_borrow %0
@@ -84,7 +84,7 @@ bb3:
 // CHECK-NOT:     load_borrow
 // CHECK:         %1 = tuple ()
 // CHECK:         return %1
-// CHEKCK       } // end sil function '@dead_load_borrow'
+// CHECK:       } // end sil function 'dead_load_borrow'
 sil [ossa] @dead_load_borrow : $@convention(thin) (@inout B) -> () {
 bb0(%0 : $*B):
   %1 = load_borrow %0
diff --git a/test/SILOptimizer/simplify_mark_dependence.sil b/test/SILOptimizer/simplify_mark_dependence.sil
new file mode 100644
index 0000000000000..474a9f16474f6
--- /dev/null
+++ b/test/SILOptimizer/simplify_mark_dependence.sil
@@ -0,0 +1,190 @@
+// RUN: %target-sil-opt %s -onone-simplification -simplify-instruction=mark_dependence -enable-experimental-feature Lifetimes | %FileCheck %s
+
+// REQUIRES: swift_feature_Lifetimes
+
+import Swift
+import Builtin
+
+class B {}
+
+struct S {
+  var a: B
+  var b: B
+}
+
+struct NE: ~Escapable {}
+
+struct NEHolder : ~Escapable {
+  var ne: NE {
+    @_lifetime(borrow self)
+    get
+  }
+}
+
+struct S2: ~Escapable {
+  var a: NE
+}
+
+sil @read_ne : $@yield_once @convention(method) (@guaranteed NEHolder) -> @lifetime(borrow 0) @yields @guaranteed NE
+sil @use_ne : $@convention(thin) (@guaranteed NE) -> ()
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_trivial_base :
+// CHECK:         %2 = copy_value %0
+// CHECK-NEXT:    return %2
+// CHECK:       } // end sil function 'mark_dependence_trivial_base'
+sil [ossa] @mark_dependence_trivial_base : $@convention(thin) (@guaranteed B, Int) -> @owned B {
+bb0(%0 : @guaranteed $B, %1 : $Int):
+  %2 = copy_value %0
+  %3 = mark_dependence %2 on %1
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_trivial_base_addr :
+// CHECK:         %3 = mark_dependence %2 on %1
+// CHECK:       } // end sil function 'mark_dependence_trivial_base_addr'
+sil [ossa] @mark_dependence_trivial_base_addr : $@convention(thin) (@guaranteed B, @in_guaranteed Int) -> @owned B {
+bb0(%0 : @guaranteed $B, %1 : $*Int):
+  %2 = copy_value %0
+  %3 = mark_dependence %2 on %1
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_non_trivial_base :
+// CHECK:         %2 = copy_value %0
+// CHECK-NEXT:    %3 = mark_dependence %2 on %1
+// CHECK-NEXT:    return %3
+// CHECK:       } // end sil function 'mark_dependence_non_trivial_base'
+sil [ossa] @mark_dependence_non_trivial_base : $@convention(thin) (@guaranteed B, @guaranteed B) -> @owned B {
+bb0(%0 : @guaranteed $B, %1 : @guaranteed $B):
+  %2 = copy_value %0
+  %3 = mark_dependence %2 on %1
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_projection :
+// CHECK:         %1 = struct_element_addr %0, #S.a
+// CHECK:         %2 = load [copy] %1
+// CHECK-NEXT:    return %2
+// CHECK:       } // end sil function 'mark_dependence_projection'
+sil [ossa] @mark_dependence_projection : $@convention(thin) (@in_guaranteed S) -> @owned B {
+bb0(%0 : $*S):
+  %1 = struct_element_addr %0, #S.a
+  %2 = mark_dependence %1 on %0
+  %3 = load [copy] %2
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_wrong_projection :
+// CHECK:         %2 = mark_dependence %0 on %1
+// CHECK:       } // end sil function 'mark_dependence_wrong_projection'
+sil [ossa] @mark_dependence_wrong_projection : $@convention(thin) (@in_guaranteed S) -> @owned S {
+bb0(%0 : $*S):
+  %1 = struct_element_addr %0, #S.a
+  %2 = mark_dependence %0 on %1
+  %3 = load [copy] %2
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_wrong_projection2 :
+// CHECK:         %3 = mark_dependence %1 on %2
+// CHECK:       } // end sil function 'mark_dependence_wrong_projection2'
+sil [ossa] @mark_dependence_wrong_projection2 : $@convention(thin) (@in_guaranteed S) -> @owned B {
+bb0(%0 : $*S):
+  %1 = struct_element_addr %0, #S.a
+  %2 = struct_element_addr %0, #S.b
+  %3 = mark_dependence %1 on %2
+  %4 = load [copy] %3
+  return %4
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_non_escapable_projection :
+// CHECK:         %2 = mark_dependence %1 on %0
+// CHECK:       } // end sil function 'mark_dependence_non_escapable_projection'
+sil [ossa] @mark_dependence_non_escapable_projection : $@convention(thin) (@in_guaranteed S2) -> @owned NE {
+bb0(%0 : $*S2):
+  %1 = struct_element_addr %0, #S2.a
+  %2 = mark_dependence %1 on %0
+  %3 = load [copy] %2
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_string_literal :
+// CHECK:         %1 = string_literal utf8 "a"
+// CHECK:         %2 = struct $UnsafePointer<Int8> (%1)
+// CHECK:         return %2
+// CHECK:       } // end sil function 'mark_dependence_string_literal'
+sil [ossa] @mark_dependence_string_literal : $@convention(thin) (@guaranteed Builtin.NativeObject) -> UnsafePointer<Int8> {
+bb0(%0 : @guaranteed $Builtin.NativeObject):
+  %1 = string_literal utf8 "a"
+  %2 = struct $UnsafePointer<Int8> (%1)
+  %3 = mark_dependence %2 on %0
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_non_literal :
+// CHECK:         %2 = struct
+// CHECK-NEXT:    %3 = mark_dependence %2 on %1
+// CHECK-NEXT:    return %3
+// CHECK:       } // end sil function 'mark_dependence_non_literal'
+sil [ossa] @mark_dependence_non_literal : $@convention(thin) (Builtin.RawPointer, @guaranteed Builtin.NativeObject) -> UnsafePointer<Int8> {
+bb0(%0 : $Builtin.RawPointer, %1 : @guaranteed $Builtin.NativeObject):
+  %2 = struct $UnsafePointer<Int8> (%0)
+  %3 = mark_dependence %2 on %1
+  return %3
+}
+
+// CHECK-LABEL: sil @mark_dependence_base :
+// CHECK-NOT:     init_existential_ref
+// CHECK-NOT:     enum
+// CHECK:         %2 = mark_dependence %0 on %1
+// CHECK-NEXT:    %3 = load %2
+// CHECK-NEXT:    return %3
+// CHECK:       } // end sil function 'mark_dependence_base'
+sil @mark_dependence_base : $@convention(thin) (@inout Builtin.Int64, @owned B) -> Builtin.Int64 {
+bb0(%0 : $*Builtin.Int64, %1 : $B):
+  %2 = init_existential_ref %1 : $B : $B, $AnyObject
+  %3 = enum $Optional<AnyObject>, #Optional.some!enumelt, %2
+  %4 = mark_dependence %0 on %3
+  %5 = load %4
+  return %5
+}
+
+// CHECK-LABEL: sil @mark_dependence_base2 :
+// CHECK-NOT:     init_existential_ref
+// CHECK-NOT:     open_existential_ref
+// CHECK:         %2 = mark_dependence %0 on %1
+// CHECK-NEXT:    %3 = load %2
+// CHECK-NEXT:    return %3
+// CHECK:       } // end sil function 'mark_dependence_base2'
+sil @mark_dependence_base2 : $@convention(thin) (@inout Builtin.Int64, @owned B) -> Builtin.Int64 {
+bb0(%0 : $*Builtin.Int64, %1 : $B):
+  %2 = init_existential_ref %1 : $B : $B, $AnyObject
+  %3 = open_existential_ref %2 to $@opened("B674783A-EF08-11E7-97D6-8C85900CB088", AnyObject) Self
+  %4 = mark_dependence %0 on %3
+  %5 = load %4
+  return %5
+}
+
+// CHECK-LABEL: sil hidden [ossa] @testChainedDependence : $@convention(thin) (@guaranteed NEHolder) -> () {
+// CHECK: bb0(%0 : @noImplicitCopy @guaranteed $NEHolder):
+// CHECK:   ([[YIELD:%[0-9]+]], [[TOKEN:%[0-9]+]]) = begin_apply %{{.*}}(%{{.*}}) : $@yield_once @convention(method) (@guaranteed NEHolder) -> @lifetime(borrow 0) @yields @guaranteed NE
+// CHECK:   [[MD1:%[0-9]+]] = mark_dependence [nonescaping] [[YIELD]] on [[TOKEN]]
+// CHECK:   mark_dependence [nonescaping] [[MD1]] on
+// CHECK-LABEL: } // end sil function 'testChainedDependence'
+sil hidden [ossa] @testChainedDependence : $@convention(thin) (@guaranteed NEHolder) -> () {
+bb0(%0 : @noImplicitCopy @guaranteed $NEHolder):
+  %2 = begin_borrow %0
+  %3 = function_ref @read_ne : $@yield_once @convention(method) (@guaranteed NEHolder) -> @lifetime(borrow 0) @yields @guaranteed NE
+  (%4, %5) = begin_apply %3(%2) : $@yield_once @convention(method) (@guaranteed NEHolder) -> @lifetime(borrow 0) @yields @guaranteed NE
+  %6 = mark_dependence [nonescaping] %4 on %5
+  %7 = mark_dependence [nonescaping] %6 on %2
+  %8 = copy_value %7
+  %9 = move_value [var_decl] %8
+  %11 = function_ref @use_ne : $@convention(thin) (@guaranteed NE) -> ()
+  %12 = apply %11(%9) : $@convention(thin) (@guaranteed NE) -> ()
+  destroy_value %9
+  %14 = end_apply %5 as $()
+  end_borrow %2
+  %16 = tuple ()
+  return %16
+}
diff --git a/test/SILOptimizer/simplify_mark_dependence_addr.sil b/test/SILOptimizer/simplify_mark_dependence_addr.sil
new file mode 100644
index 0000000000000..c5bd724dbe494
--- /dev/null
+++ b/test/SILOptimizer/simplify_mark_dependence_addr.sil
@@ -0,0 +1,124 @@
+// RUN: %target-sil-opt %s -onone-simplification -simplify-instruction=mark_dependence_addr -enable-experimental-feature LifetimeDependence | %FileCheck %s
+
+// REQUIRES: swift_feature_LifetimeDependence
+
+import Swift
+import Builtin
+
+class B {}
+
+struct S {
+  var a: B
+  var b: B
+}
+
+struct NE: ~Escapable {}
+
+struct S2: ~Escapable {
+  var a: NE
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_trivial_base :
+// CHECK-NOT:     mark_dependence_addr
+// CHECK:       } // end sil function 'mark_dependence_trivial_base'
+sil [ossa] @mark_dependence_trivial_base : $@convention(thin) (@in_guaranteed B, Int) -> () {
+bb0(%0 : $*B, %1 : $Int):
+  mark_dependence_addr %0 on %1
+  %3 = tuple ()
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_trivial_base_addr :
+// CHECK:         mark_dependence_addr %0 on %1
+// CHECK:       } // end sil function 'mark_dependence_trivial_base_addr'
+sil [ossa] @mark_dependence_trivial_base_addr : $@convention(thin) (@in_guaranteed B, @in_guaranteed Int) -> () {
+bb0(%0 : $*B, %1 : $*Int):
+  mark_dependence_addr %0 on %1
+  %3 = tuple ()
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_non_trivial_base :
+// CHECK:         mark_dependence_addr %0 on %1
+// CHECK:       } // end sil function 'mark_dependence_non_trivial_base'
+sil [ossa] @mark_dependence_non_trivial_base : $@convention(thin) (@in_guaranteed B, @guaranteed B) -> () {
+bb0(%0 : $*B, %1 : @guaranteed $B):
+  mark_dependence_addr %0 on %1
+  %3 = tuple ()
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_projection :
+// CHECK-NOT:     mark_dependence_addr
+// CHECK:       } // end sil function 'mark_dependence_projection'
+sil [ossa] @mark_dependence_projection : $@convention(thin) (@in_guaranteed S) -> () {
+bb0(%0 : $*S):
+  %1 = struct_element_addr %0, #S.a
+  mark_dependence_addr %1 on %0
+  %3 = tuple ()
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_wrong_projection :
+// CHECK:         mark_dependence_addr %0 on %1
+// CHECK:       } // end sil function 'mark_dependence_wrong_projection'
+sil [ossa] @mark_dependence_wrong_projection : $@convention(thin) (@in_guaranteed S) -> () {
+bb0(%0 : $*S):
+  %1 = struct_element_addr %0, #S.a
+  mark_dependence_addr %0 on %1
+  %3 = tuple ()
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_wrong_projection2 :
+// CHECK:         mark_dependence_addr %1 on %2
+// CHECK:       } // end sil function 'mark_dependence_wrong_projection2'
+sil [ossa] @mark_dependence_wrong_projection2 : $@convention(thin) (@in_guaranteed S) -> () {
+bb0(%0 : $*S):
+  %1 = struct_element_addr %0, #S.a
+  %2 = struct_element_addr %0, #S.b
+  mark_dependence_addr %1 on %2
+  %4 = tuple ()
+  return %4
+}
+
+// CHECK-LABEL: sil [ossa] @mark_dependence_non_escapable_projection :
+// CHECK:         mark_dependence_addr %1 on %0
+// CHECK:       } // end sil function 'mark_dependence_non_escapable_projection'
+sil [ossa] @mark_dependence_non_escapable_projection : $@convention(thin) (@in_guaranteed S2) -> () {
+bb0(%0 : $*S2):
+  %1 = struct_element_addr %0, #S2.a
+  mark_dependence_addr %1 on %0
+  %4 = tuple ()
+  return %4
+}
+
+// CHECK-LABEL: sil @mark_dependence_base :
+// CHECK-NOT:     init_existential_ref
+// CHECK-NOT:     enum
+// CHECK:         mark_dependence_addr %0 on %1
+// CHECK:       } // end sil function 'mark_dependence_base'
+sil @mark_dependence_base : $@convention(thin) (@inout Builtin.Int64, @owned B) -> () {
+bb0(%0 : $*Builtin.Int64, %1 : $B):
+  %2 = init_existential_ref %1 : $B : $B, $AnyObject
+  %3 = enum $Optional<AnyObject>, #Optional.some!enumelt, %2
+  mark_dependence_addr %0 on %3
+  %5 = tuple ()
+  return %5
+}
+
+// CHECK-LABEL: sil @mark_dependence_base2 :
+// CHECK-NOT:     init_existential_ref
+// CHECK-NOT:     open_existential_ref
+// CHECK:         mark_dependence_addr %0 on %1
+// CHECK:       } // end sil function 'mark_dependence_base2'
+sil @mark_dependence_base2 : $@convention(thin) (@inout Builtin.Int64, @owned B) -> () {
+bb0(%0 : $*Builtin.Int64, %1 : $B):
+  %2 = init_existential_ref %1 : $B : $B, $AnyObject
+  %3 = open_existential_ref %2 to $@opened("B674783A-EF08-11E7-97D6-8C85900CB088", AnyObject) Self
+  mark_dependence_addr %0 on %3
+  %5 = tuple ()
+  return %5
+}
+
+
diff --git a/test/SILOptimizer/simplify_struct.sil b/test/SILOptimizer/simplify_struct.sil
new file mode 100644
index 0000000000000..856986a3416bb
--- /dev/null
+++ b/test/SILOptimizer/simplify_struct.sil
@@ -0,0 +1,201 @@
+// RUN: %target-sil-opt %s -simplification -simplify-instruction=struct | %FileCheck %s
+
+import Swift
+import Builtin
+
+struct S {
+  let a: String
+  let b: Int
+}
+
+struct Outer {
+  let s: S
+}
+
+// CHECK-LABEL: sil [ossa] @simple_delay_struct :
+// CHECK:       bb0
+// CHECK-NEXT:    [[B:%.*]] = begin_borrow %0
+// CHECK-NEXT:    fix_lifetime [[B]]
+// CHECK-NEXT:    fix_lifetime %1
+// CHECK-NEXT:    end_borrow [[B]]
+// CHECK-NEXT:    [[S:%.*]] = struct $S (%0, %1)
+// CHECK-NEXT:    destroy_value [[S]]
+// CHECK:       } // end sil function 'simple_delay_struct'
+sil [ossa] @simple_delay_struct : $@convention(thin) (@owned String, Int) -> () {
+bb0(%0 : @owned $String, %1 : $Int):
+  %2 = struct $S (%0, %1)
+  debug_value %2, name "x"
+  %3 = begin_borrow %2
+  debug_value %3, name "x"
+  %4 = struct_extract %3, #S.a
+  %5 = struct_extract %3, #S.b
+  fix_lifetime %4
+  fix_lifetime %5
+  end_borrow %3
+  destroy_value %2
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [ossa] @test_nested :
+// CHECK:       bb0
+// CHECK-NEXT:    [[B:%.*]] = begin_borrow %0
+// CHECK-NEXT:    fix_lifetime [[B]]
+// CHECK-NEXT:    fix_lifetime %1
+// CHECK-NEXT:    end_borrow [[B]]
+// CHECK-NEXT:    [[S:%.*]] = struct $S (%0, %1)
+// CHECK-NEXT:    [[OUTER:%.*]] = struct $Outer ([[S]])
+// CHECK-NEXT:    destroy_value [[OUTER]]
+// CHECK:       } // end sil function 'test_nested'
+sil [ossa] @test_nested : $@convention(thin) (@owned String, Int) -> () {
+bb0(%0 : @owned $String, %1 : $Int):
+  %2 = struct $S (%0, %1)
+  %3 = struct $Outer (%2)
+  %4 = begin_borrow %3
+  %5 = struct_extract %4, #Outer.s
+  %6 = struct_extract %5, #S.a
+  %7 = struct_extract %5, #S.b
+  fix_lifetime %6
+  fix_lifetime %7
+  end_borrow %4
+  destroy_value %3
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [ossa] @multi_lifetime_ends :
+// CHECK:       bb0
+// CHECK-NEXT:    [[B:%.*]] = begin_borrow %0
+// CHECK-NEXT:    fix_lifetime [[B]]
+// CHECK-NEXT:    fix_lifetime %1
+// CHECK-NEXT:    end_borrow [[B]]
+// CHECK:       bb1:
+// CHECK-NEXT:    [[S1:%.*]] = struct $S (%0, %1)
+// CHECK-NEXT:    destroy_value [[S1]]
+// CHECK:       bb2:
+// CHECK-NEXT:    [[S2:%.*]] = struct $S (%0, %1)
+// CHECK-NEXT:    destroy_value [[S2]]
+// CHECK:       } // end sil function 'multi_lifetime_ends'
+sil [ossa] @multi_lifetime_ends : $@convention(thin) (@owned String, Int) -> () {
+bb0(%0 : @owned $String, %1 : $Int):
+  %2 = struct $S (%0, %1)
+  %3 = begin_borrow %2
+  %4 = struct_extract %3, #S.a
+  %5 = struct_extract %3, #S.b
+  fix_lifetime %4
+  fix_lifetime %5
+  end_borrow %3
+  cond_br undef, bb1, bb2
+bb1:
+  destroy_value %2
+  br bb3
+bb2:
+  destroy_value %2
+  br bb3
+bb3:
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [ossa] @multi_borrows :
+// CHECK:       bb1:
+// CHECK-NEXT:    [[B:%.*]] = begin_borrow %0
+// CHECK-NEXT:    fix_lifetime [[B]]
+// CHECK-NEXT:    end_borrow [[B]]
+// CHECK:       bb2:
+// CHECK-NEXT:    fix_lifetime %1
+// CHECK:       bb3:
+// CHECK-NEXT:    [[S:%.*]] = struct $S (%0, %1)
+// CHECK-NEXT:    destroy_value [[S]]
+// CHECK:       } // end sil function 'multi_borrows'
+sil [ossa] @multi_borrows : $@convention(thin) (@owned String, Int) -> () {
+bb0(%0 : @owned $String, %1 : $Int):
+  %2 = struct $S (%0, %1)
+  cond_br undef, bb1, bb2
+bb1:
+  %3 = begin_borrow %2
+  %4 = struct_extract %3, #S.a
+  fix_lifetime %4
+  end_borrow %3
+  br bb3
+bb2:
+  %7 = begin_borrow %2
+  %8 = struct_extract %7, #S.b
+  fix_lifetime %8
+  end_borrow %7
+  br bb3
+bb3:
+  destroy_value %2
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [ossa] @unknown_struct_use :
+// CHECK:         struct_extract
+// CHECK:         struct_extract
+// CHECK:       } // end sil function 'unknown_struct_use'
+sil [ossa] @unknown_struct_use : $@convention(thin) (@owned String, Int) -> () {
+bb0(%0 : @owned $String, %1 : $Int):
+  %2 = struct $S (%0, %1)
+  fix_lifetime %2
+  %3 = begin_borrow %2
+  %4 = struct_extract %3, #S.a
+  %5 = struct_extract %3, #S.b
+  fix_lifetime %4
+  fix_lifetime %5
+  end_borrow %3
+  destroy_value %2
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [ossa] @unknown_borrow_use :
+// CHECK:         struct_extract
+// CHECK:         struct_extract
+// CHECK:       } // end sil function 'unknown_borrow_use'
+sil [ossa] @unknown_borrow_use : $@convention(thin) (@owned String, Int) -> () {
+bb0(%0 : @owned $String, %1 : $Int):
+  %2 = struct $S (%0, %1)
+  %3 = begin_borrow %2
+  fix_lifetime %3
+  %4 = struct_extract %3, #S.a
+  %5 = struct_extract %3, #S.b
+  fix_lifetime %4
+  fix_lifetime %5
+  end_borrow %3
+  destroy_value %2
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [ossa] @no_borrows :
+// CHECK:         %2 = struct
+// CHECK:         destroy_value %2
+// CHECK:       } // end sil function 'no_borrows'
+sil [ossa] @no_borrows : $@convention(thin) (@owned String, Int) -> () {
+bb0(%0 : @owned $String, %1 : $Int):
+  %2 = struct $S (%0, %1)
+  destroy_value %2
+  %r = tuple ()
+  return %r : $()
+}
+
+// TODO: remove this test once we require complete OSSA lifetimes
+// CHECK-LABEL: sil [ossa] @incomplete_lifetimes :
+// CHECK:       bb0
+// CHECK-NEXT:    [[B:%.*]] = begin_borrow %0
+// CHECK-NEXT:    fix_lifetime [[B]]
+// CHECK-NEXT:    fix_lifetime %1
+// CHECK-NEXT:    unreachable
+// CHECK:       } // end sil function 'incomplete_lifetimes'
+sil [ossa] @incomplete_lifetimes : $@convention(thin) (@owned String, Int) -> () {
+bb0(%0 : @owned $String, %1 : $Int):
+  %2 = struct $S (%0, %1)
+  %3 = begin_borrow %2
+  %4 = struct_extract %3, #S.a
+  %5 = struct_extract %3, #S.b
+  fix_lifetime %4
+  fix_lifetime %5
+  unreachable
+}
+
diff --git a/test/SILOptimizer/simplify_unchecked_addr_cast.sil b/test/SILOptimizer/simplify_unchecked_addr_cast.sil
new file mode 100644
index 0000000000000..43a83f0f7dd13
--- /dev/null
+++ b/test/SILOptimizer/simplify_unchecked_addr_cast.sil
@@ -0,0 +1,73 @@
+// RUN: %target-sil-opt %s -onone-simplification -simplify-instruction=unchecked_addr_cast | %FileCheck %s
+// RUN: %target-sil-opt %s -simplification -simplify-instruction=unchecked_addr_cast | %FileCheck %s
+
+import Swift
+import Builtin
+
+// CHECK-LABEL: sil [ossa] @same_type :
+// CHECK-NOT:     unchecked_addr_cast
+// CHECK:         %1 = load [trivial] %0
+// CHECK:      } // end sil function 'same_type'
+sil [ossa] @same_type : $@convention(thin) (@inout Int) -> Int {
+bb0(%0 : $*Int):
+  %1 = unchecked_addr_cast %0 to $*Int
+  %2 = load [trivial] %1
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @not_same_type :
+// CHECK:         %1 = unchecked_addr_cast %0 to $*Float
+// CHECK:         %2 = load [trivial] %1
+// CHECK:      } // end sil function 'not_same_type'
+sil [ossa] @not_same_type : $@convention(thin) (@inout Int) -> Float {
+bb0(%0 : $*Int):
+  %1 = unchecked_addr_cast %0 to $*Float
+  %2 = load [trivial] %1
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @double_cast :
+// CHECK:         %1 = unchecked_addr_cast %0 to $*Bool
+// CHECK:         %2 = load [trivial] %1
+// CHECK:      } // end sil function 'double_cast'
+sil [ossa] @double_cast : $@convention(thin) (@inout Int) -> Bool {
+bb0(%0 : $*Int):
+  %1 = unchecked_addr_cast %0 to $*Float
+  %2 = unchecked_addr_cast %1 to $*Bool
+  %3 = load [trivial] %2
+  return %3
+}
+
+// CHECK-LABEL: sil [ossa] @vector_base :
+// CHECK:         %1 = vector_base_addr %0
+// CHECK:         %2 = load [trivial] %1
+// CHECK:      } // end sil function 'vector_base'
+sil [ossa] @vector_base : $@convention(thin) (@inout Builtin.FixedArray<10, Int>) -> Int {
+bb0(%0 : $*Builtin.FixedArray<10, Int>):
+  %1 = unchecked_addr_cast %0 to $*Int
+  %2 = load [trivial] %1
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @vector_base_wrong_type :
+// CHECK:         %1 = unchecked_addr_cast %0 to $*Bool
+// CHECK:         %2 = load [trivial] %1
+// CHECK:      } // end sil function 'vector_base_wrong_type'
+sil [ossa] @vector_base_wrong_type : $@convention(thin) (@inout Builtin.FixedArray<10, Int>) -> Bool {
+bb0(%0 : $*Builtin.FixedArray<10, Int>):
+  %1 = unchecked_addr_cast %0 to $*Bool
+  %2 = load [trivial] %1
+  return %2
+}
+
+// CHECK-LABEL: sil [ossa] @vector_base_function_type :
+// CHECK:         %1 = vector_base_addr %0
+// CHECK:         %2 = load [copy] %1
+// CHECK:      } // end sil function 'vector_base_function_type'
+sil [ossa] @vector_base_function_type : $@convention(thin) (@inout Builtin.FixedArray<10, ()->()>) -> @owned @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <()> {
+bb0(%0 : $*Builtin.FixedArray<10, ()->()>):
+  %1 = unchecked_addr_cast %0 to $*@callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <()>
+  %2 = load [copy] %1
+  return %2
+}
+
diff --git a/test/SILOptimizer/simplify_unconditional_check_cast.sil b/test/SILOptimizer/simplify_unconditional_check_cast.sil
index 47e8c4ccb1eec..eaa17e98451df 100644
--- a/test/SILOptimizer/simplify_unconditional_check_cast.sil
+++ b/test/SILOptimizer/simplify_unconditional_check_cast.sil
@@ -1,7 +1,10 @@
 // RUN: %target-sil-opt -enable-sil-verify-all %s -simplification -simplify-instruction=unconditional_checked_cast | %FileCheck %s
 
+// REQUIRES: concurrency
+
 import Swift
 import Builtin
+import _Concurrency
 
 protocol P {}
 protocol PC: AnyObject {}
@@ -12,6 +15,8 @@ struct T {}
 
 class C {}
 
+struct X : @MainActor P {}
+
 // CHECK-LABEL: sil [ossa] @test_conforming_struct :
 // CHECK:         %1 = init_existential_metatype %0, $@thick any P.Type
 // CHECK-NEXT:    return %1
@@ -32,15 +37,16 @@ bb0(%0 : $@thick T.Type):
   return %1
 }
 
-
 // CHECK-LABEL: sil [ossa] @test_non_metatype :
 // CHECK:         %1 = unconditional_checked_cast %0
-// CHECK-NEXT:    return %1
+// CHECK-NEXT:    %2 = copy_value %1
+// CHECK-NEXT:    return %2
 // CHECK:       } // end sil function 'test_non_metatype'
-sil [ossa] @test_non_metatype : $@convention(thin) (@guaranteed C) -> any PC {
+sil [ossa] @test_non_metatype : $@convention(thin) (@guaranteed C) -> @owned any PC {
 bb0(%0 : @guaranteed $C):
   %1 = unconditional_checked_cast %0 to any PC
-  return %1
+  %2 = copy_value %1
+  return %2
 }
 
 // CHECK-LABEL: sil [ossa] @test_non_existential_target :
@@ -52,3 +58,14 @@ bb0(%0 : $@thick S.Type):
   %1 = unconditional_checked_cast %0 to Int.Type
   return %1
 }
+
+// CHECK-LABEL: sil [ossa] @test_isolated_conformance :
+// CHECK:         %1 = unconditional_checked_cast %0
+// CHECK-NEXT:    return %1
+// CHECK:       } // end sil function 'test_isolated_conformance'
+sil [ossa] @test_isolated_conformance : $@convention(thin) (@thick X.Type) -> @thick any P.Type {
+bb0(%0 : $@thick X.Type):
+  %1 = unconditional_checked_cast %0 to any P.Type
+  return %1
+}
+
diff --git a/test/SILOptimizer/simplify_value_to_bridge_object.sil b/test/SILOptimizer/simplify_value_to_bridge_object.sil
index e83df68070631..848ed70e82a0a 100644
--- a/test/SILOptimizer/simplify_value_to_bridge_object.sil
+++ b/test/SILOptimizer/simplify_value_to_bridge_object.sil
@@ -22,15 +22,16 @@ bb0(%0 : $Builtin.Int64):
 // CHECK:         %1 = value_to_bridge_object %0
 // CHECK:         %2 = value_to_bridge_object %0
 // CHECK:         %3 = tuple (%1 : $Builtin.BridgeObject, %2 : $Builtin.BridgeObject)
-// CHECK:         return %3
+// CHECK:         %4 = copy_value %3
+// CHECK:         return %4
 // CHECK:       } // end sil function 'keep_both_vtbo_instructions'
-sil [ossa] @keep_both_vtbo_instructions : $@convention(thin) (Builtin.Int64) -> (Builtin.BridgeObject, Builtin.BridgeObject) {
+sil [ossa] @keep_both_vtbo_instructions : $@convention(thin) (Builtin.Int64) -> @owned (Builtin.BridgeObject, Builtin.BridgeObject) {
 bb0(%0 : $Builtin.Int64):
   %1 = value_to_bridge_object %0 : $Builtin.Int64
   %2 = unchecked_trivial_bit_cast %1 : $Builtin.BridgeObject to $UInt64
   %3 = struct_extract %2 : $UInt64, #UInt64._value
   %4 = value_to_bridge_object %3 : $Builtin.Int64
   %5 = tuple (%1 : $Builtin.BridgeObject, %4 : $Builtin.BridgeObject)
-  return %5 : $(Builtin.BridgeObject, Builtin.BridgeObject)
+  %6 = copy_value %5
+  return %6
 }
-
diff --git a/test/SILOptimizer/small_projection_path_unit.sil b/test/SILOptimizer/small_projection_path_unit.sil
new file mode 100644
index 0000000000000..6cf3cdabd0994
--- /dev/null
+++ b/test/SILOptimizer/small_projection_path_unit.sil
@@ -0,0 +1,9 @@
+// RUN: %target-sil-opt -test-runner -sil-disable-input-verify %s -o /dev/null
+
+sil_stage raw
+
+sil @small_projection_path_unit_tests : $@convention(thin) () -> () {
+bb0:
+  specify_test "small_projection_path"
+  unreachable
+}
diff --git a/test/SILOptimizer/span.swift b/test/SILOptimizer/span.swift
new file mode 100644
index 0000000000000..1775e9cc266dd
--- /dev/null
+++ b/test/SILOptimizer/span.swift
@@ -0,0 +1,8 @@
+// RUN: %target-swift-frontend %s -parse-as-library -disable-availability-checking -emit-ir -o /dev/null
+
+// Check that the MoveOnlyWrappedTypeEliminator doesn't crash
+func consumingArray(_ arr: consuming [Int]) {
+  let s = arr.mutableSpan;
+  _ = consume s
+}
+
diff --git a/test/SILOptimizer/span_bounds_check_tests.swift b/test/SILOptimizer/span_bounds_check_tests.swift
index 0f0f9c0b356ae..2343a6ecb8fc9 100644
--- a/test/SILOptimizer/span_bounds_check_tests.swift
+++ b/test/SILOptimizer/span_bounds_check_tests.swift
@@ -1,15 +1,15 @@
 // RUN: %target-swift-frontend %s -emit-sil -O \
 // RUN:   -disable-availability-checking \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   | %FileCheck %s --check-prefix=CHECK-SIL
 
 // RUN: %target-swift-frontend %s -emit-ir -O \
 // RUN:   -disable-availability-checking \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   | %FileCheck %s  --check-prefix=CHECK-IR
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_stdlib_no_asserts, optimized_stdlib
 
 // Bounds check should be eliminated
@@ -28,7 +28,7 @@ public func span_sum_iterate_to_count_wo_trap(_ v: Span<Int>) -> Int {
   for i in 0..<v.count {
     sum &+= v[i]
   }
-  return sum
+  return sum &+ 1 // adding 1 to avoid LLVM function merging
 }
 
 // Bounds check should be eliminated
@@ -175,15 +175,10 @@ public func span_sum_iterate_to_deducible_count2_with_trap(_ v: Span<Int>, _ n:
 }
 
 // Bounds check should be eliminated
-// SIL optimizer hoists bounds checks from the loop
+// TODO: there should not be any cond_fail in this function
 
 // CHECK-SIL-LABEL: sil @$s23span_bounds_check_tests0A29_iterate_over_indices_wo_trapySis4SpanVySiGF :
-// CHECK-SIL: bb1
-// CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
-// CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
-// CHECK-SIL: bb3
 // CHECK-SIL-NOT: cond_fail {{.*}}, "Index out of bounds"
-// CHECK-SIL: cond_br
 // CHECK-SIL-LABEL: } // end sil function '$s23span_bounds_check_tests0A29_iterate_over_indices_wo_trapySis4SpanVySiGF'
 
 // CHECK-IR: define {{.*}} @"$s23span_bounds_check_tests0A29_iterate_over_indices_wo_trapySis4SpanVySiGF"
@@ -200,12 +195,7 @@ public func span_iterate_over_indices_wo_trap(_ v: Span<Int>) -> Int {
 // SIL optimizer hoists bounds checks from the loop
 
 // CHECK-SIL-LABEL: sil @$s23span_bounds_check_tests0A31_iterate_over_indices_with_trapySis4SpanVySiGF :
-// CHECK-SIL: bb1
-// CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
-// CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
-// CHECK-SIL: bb3
 // CHECK-SIL-NOT: cond_fail {{.*}}, "Index out of bounds"
-// CHECK-SIL: cond_br
 // CHECK-SIL-LABEL: } // end sil function '$s23span_bounds_check_tests0A31_iterate_over_indices_with_trapySis4SpanVySiGF'
 public func span_iterate_over_indices_with_trap(_ v: Span<Int>) -> Int {
   var sum = 0
@@ -254,12 +244,11 @@ public func span_search<T : Equatable>(_ v: Span<T>, _ elem: T) -> Int? {
   return nil
 }
 
-// Bounds check should be eliminated
+// TODO: Bounds check should be eliminated
 
 // CHECK-SIL-LABEL: sil @$s23span_bounds_check_tests0A11_search_splySiSgs4SpanVySiG_SitF :
 // CHECK-SIL: bb3:
 // CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
-// CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_br
 // CHECK-SIL-LABEL: } // end sil function '$s23span_bounds_check_tests0A11_search_splySiSgs4SpanVySiG_SitF'
 public func span_search_spl(_ v: Span<Int>, _ elem: Int) -> Int? {
@@ -328,7 +317,7 @@ public func mutate_span(_ v: inout Span<Int>) { }
 // CHECK-SIL-NOT: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_br
 // CHECK-SIL-LABEL: } // end sil function '$s23span_bounds_check_tests06inout_A33_sum_iterate_to_unknown_with_trapySis4SpanVySiGz_SitF'
-@lifetime(v: copy v)
+@_lifetime(v: copy v)
 public func inout_span_sum_iterate_to_unknown_with_trap(_ v: inout Span<Int>, _ n: Int) -> Int {
   var sum = 0
   for i in 0...n {
@@ -343,7 +332,7 @@ public func inout_span_sum_iterate_to_unknown_with_trap(_ v: inout Span<Int>, _
 // CHECK-SIL: cond_fail {{.*}}, "Index out of bounds"
 // CHECK-SIL: cond_br
 // CHECK-SIL-LABEL: } // end sil function '$s23span_bounds_check_tests06inout_A41_sum_iterate_to_unknown_with_trap_dontoptySis4SpanVySiGz_SitF'
-@lifetime(v: copy v)
+@_lifetime(v: copy v)
 public func inout_span_sum_iterate_to_unknown_with_trap_dontopt(_ v: inout Span<Int>, _ n: Int) -> Int {
   var sum = 0
   for i in 0...n {
diff --git a/test/SILOptimizer/span_bounds_check_tests2.swift b/test/SILOptimizer/span_bounds_check_tests2.swift
new file mode 100644
index 0000000000000..d19da62419fdc
--- /dev/null
+++ b/test/SILOptimizer/span_bounds_check_tests2.swift
@@ -0,0 +1,21 @@
+// RUN: %target-swift-frontend %s -emit-ir -O -disable-availability-checking -enable-experimental-feature Lifetimes | %FileCheck %s  --check-prefix=CHECK-IR
+
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_stdlib_no_asserts, optimized_stdlib
+// REQUIRES: CPU=arm64 || CPU=arm64e
+
+// Check that the loop is fully optimized, including bounds check elimination and vectorization.
+
+// CHECK-IR-LABEL: define {{.*}} @"$s24span_bounds_check_tests24loop4over5usingSis4SpanVys5UInt8VG_AFySiGtF"
+// CHECK-IR:       vector.body:
+// CHECK-IR:       ret
+public func loop(over a: borrowing Span<UInt8>, using b: borrowing Span<Int>) -> Int {
+  var result = 0
+  precondition(UInt8.max < b.count)
+  for i in a.indices {
+    let idx = Int(a[i])
+    result &+= b[idx]
+  }
+  return result
+}
+
diff --git a/test/SILOptimizer/specialize_casts.sil b/test/SILOptimizer/specialize_casts.sil
new file mode 100644
index 0000000000000..143049b780b57
--- /dev/null
+++ b/test/SILOptimizer/specialize_casts.sil
@@ -0,0 +1,62 @@
+// RUN: %target-sil-opt -enable-sil-verify-all -generic-specializer %s | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+sil_stage canonical
+
+import Builtin
+import Swift
+import SwiftShims
+
+import Foundation
+
+public enum ResultType : Equatable {
+  case object(NSObject)
+  case undefined
+  internal init<T>(metatypeOf value: T)
+}
+
+// CHECK-LABEL: // specialized callee_anyobject
+// CHECK-LABEL: sil shared [ossa] @$s16callee_anyobjectyXl_Tt0g5 :
+// CHECK: checked_cast_addr_br 
+// CHECK-LABEL: } // end sil function '$s16callee_anyobjectyXl_Tt0g5'
+sil hidden [ossa] @callee_anyobject : $@convention(method) <T> (@in T, @thin ResultType.Type) -> @owned ResultType {
+bb0(%0 : $*T, %1 : $@thin ResultType.Type):
+  %3 = alloc_stack $T
+  copy_addr %0 to [init] %3
+  %5 = alloc_stack $NSObject
+  checked_cast_addr_br copy_on_success T in %3 to NSObject in %5, bb1, bb2
+
+bb1:
+  destroy_addr %0
+  %8 = enum $ResultType, #ResultType.undefined!enumelt
+  destroy_addr %5
+  dealloc_stack %5
+  br bb5(%8)
+
+bb2:
+  destroy_addr %0
+  dealloc_stack %5
+  %28 = enum $ResultType, #ResultType.undefined!enumelt
+  br bb5(%28)
+
+bb5(%30 : @owned $ResultType):
+  destroy_addr %3
+  dealloc_stack %3
+  %34 = move_value [lexical] %30
+  return %34
+}
+
+sil hidden [ossa] @caller_anyobject : $@convention(thin) (@owned AnyObject) -> () {
+bb0(%0 : @owned $AnyObject):
+  %1 = metatype $@thin ResultType.Type
+  %2 = alloc_stack $AnyObject
+  store %0 to [init] %2
+  %4 = function_ref @callee_anyobject : $@convention(method) <τ_0_0> (@in τ_0_0, @thin ResultType.Type) -> @owned ResultType
+  %5 = apply %4<AnyObject>(%2, %1) : $@convention(method) <τ_0_0> (@in τ_0_0, @thin ResultType.Type) -> @owned ResultType
+  dealloc_stack %2
+  destroy_value %5
+  %8 = tuple ()
+  return %8
+}
+
diff --git a/test/SILOptimizer/specialize_move_only_wrapped_type.swift b/test/SILOptimizer/specialize_move_only_wrapped_type.swift
new file mode 100644
index 0000000000000..d6c36f4fd47f0
--- /dev/null
+++ b/test/SILOptimizer/specialize_move_only_wrapped_type.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend -emit-sil -O %s
+
+public struct Mutex<T> {
+  public init(_: T) {}
+}
+
+public struct Locked<T> {
+  public let mutex: Mutex<T>
+
+  public init(_ rawValue: consuming T) {
+    mutex = Mutex(rawValue)
+  }
+}
+
+_ = Locked { }
diff --git a/test/SILOptimizer/specialize_opaque.sil b/test/SILOptimizer/specialize_opaque.sil
index 934972b39cac6..3035e9f6dcc17 100644
--- a/test/SILOptimizer/specialize_opaque.sil
+++ b/test/SILOptimizer/specialize_opaque.sil
@@ -12,6 +12,8 @@ import Builtin
 // CHECK:   %{{.*}} = apply [[F]](%0, %1) : $@convention(thin) (Builtin.Int64, Builtin.Int64) -> ()
 // CHECK-NOT: copy_value
 // CHECK-NOT: destroy_value
+// CHECK-NOT: extend_lifetime
+// CHECK-NOT: end_lifetime
 // CHECK:   return %{{.*}} : $()
 // CHECK-LABEL: } // end sil function '$s3fooBi64__Tg5'
 sil hidden [ossa] @foo : $@convention(thin) <T> (@in T, @in T) -> () {
@@ -19,9 +21,11 @@ bb0(%0 : @owned $T, %1 : @owned $T):
   %f = function_ref @foo : $@convention(thin) <τ_0_0> (@in τ_0_0, @in τ_0_0) -> ()
   %cp0 = copy_value %0 : $T
   %cp1 = copy_value %1 : $T
+  %cp3 = explicit_copy_value %1 : $T
   %call = apply %f<T>(%cp0, %cp1) : $@convention(thin) <τ_0_0> (@in τ_0_0, @in τ_0_0) -> ()
   destroy_value %1 : $T
-  destroy_value %0 : $T
+  end_lifetime %0 : $T
+  extend_lifetime %cp3 : $T
   %10 = tuple ()
   return %10 : $()
 }
diff --git a/test/SILOptimizer/specialize_opaque_type_archetypes.swift b/test/SILOptimizer/specialize_opaque_type_archetypes.swift
index dfb75b3f02beb..bd64c80c5f2db 100644
--- a/test/SILOptimizer/specialize_opaque_type_archetypes.swift
+++ b/test/SILOptimizer/specialize_opaque_type_archetypes.swift
@@ -421,12 +421,12 @@ struct PAEM : P4EM {
 // CHECK:   apply [[F]]([[V]])
 
 // CHECK-64-LABEL: sil hidden @$s1A2PAV4testyyF : $@convention(method) (PA) -> ()
-// CHECK-64:   [[V:%.*]] = integer_literal $Builtin.Int64, 5
-// CHECK-64:   [[I:%.*]] = struct $Int64 ([[V]] : $Builtin.Int64)
-// CHECK-64:   [[F:%.*]] = function_ref @$s1A4usePyyxAA1PRzlFs5Int64V_Tg5
-// CHECK-64:   apply [[F]]([[I]]) : $@convention(thin) (Int64) -> ()
-// CHECK-64:   apply [[F]]([[I]]) : $@convention(thin) (Int64) -> ()
-
+// CHECK-64:         [[V:%.*]] = integer_literal $Builtin.Int64, 5
+// CHECK-64-DAG:     [[I:%.*]] = struct $Int64 ([[V]] : $Builtin.Int64)
+// CHECK-64-DAG:     [[F:%.*]] = function_ref @$s1A4usePyyxAA1PRzlFs5Int64V_Tg5
+// CHECK-64:         apply [[F]]([[I]]) : $@convention(thin) (Int64) -> ()
+// CHECK-64:         apply [[F]]([[I]]) : $@convention(thin) (Int64) -> ()
+// CHECK-64:       } // end sil function '$s1A2PAV4testyyF'
 @inline(never)
 func testIt<T>(cl: (Int64) throws -> T) {
  do {
diff --git a/test/SILOptimizer/specialize_ossa.sil b/test/SILOptimizer/specialize_ossa.sil
index 72de52e5b8661..3a15dac511c06 100644
--- a/test/SILOptimizer/specialize_ossa.sil
+++ b/test/SILOptimizer/specialize_ossa.sil
@@ -1665,3 +1665,22 @@ bb0(%0 : $Int):
   dealloc_stack %1
   return %11
 }
+
+
+sil hidden [ossa] @$s_custom_not_demangable_name : $@convention(thin) <T> (@thick T.Type) -> () {
+bb0(%0 : $@thick T.Type):
+  %8 = tuple ()
+  return %8 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @call_custom_name :
+// CHECK:         function_ref @$s29$s_custom_not_demangable_nameSi_Ttg5 : $@convention(thin) () -> ()
+// CHECK:       } // end sil function 'call_custom_name'
+sil [ossa] @call_custom_name : $@convention(thin) () -> () {
+bb0:
+  %2 = function_ref @$s_custom_not_demangable_name : $@convention(thin) <τ_0_0> (@thick τ_0_0.Type) -> ()
+  %3 = metatype $@thick Int.Type
+  %4 = apply %2<Int>(%3) : $@convention(thin) <τ_0_0> (@thick τ_0_0.Type) -> ()
+  %5 = tuple ()
+  return %5 : $()
+}
diff --git a/test/SILOptimizer/specialize_output_generic_signature.swift b/test/SILOptimizer/specialize_output_generic_signature.swift
new file mode 100644
index 0000000000000..748d229657295
--- /dev/null
+++ b/test/SILOptimizer/specialize_output_generic_signature.swift
@@ -0,0 +1,17 @@
+// RUN: %target-swift-frontend -emit-sil -O %s
+
+extension Array: Comparable where Element: Comparable {
+  public static func < (lhs: Array<Element>, rhs: Array<Element>) -> Bool {
+    // Contents do not matter
+    for (l, r) in zip(lhs, rhs) { if l != r { return l < r } }
+    return lhs.count < rhs.count
+  }
+}
+
+public struct Wrapper<Symbol: Hashable & Comparable>: Hashable {
+  public var partitions: PartitionSet<Array<Symbol>>
+}
+
+public struct PartitionSet<Symbol: Hashable & Comparable>: Equatable, Hashable {
+  public var partitions: Set<Set<Symbol>>
+}
diff --git a/test/SILOptimizer/specialize_self_conforming.swift b/test/SILOptimizer/specialize_self_conforming.swift
index 40aea0ce9bbb3..50421f0623530 100644
--- a/test/SILOptimizer/specialize_self_conforming.swift
+++ b/test/SILOptimizer/specialize_self_conforming.swift
@@ -5,14 +5,26 @@
 
 import Foundation
 
-@objc protocol P {}
+@objc protocol P: Q {
+  func foo()
+}
+
+@objc protocol Q {
+  func bar()
+}
+
+@_optimize(none)
+func takesP<T : P>(_ t: T) {}
 
 @_optimize(none)
-func takesP<T : P>(_: T) {}
+func takesQ<T : Q>(_ t: T) {}
 
 @inline(__always)
 func callsTakesP<T : P>(_ t: T) {
   takesP(t)
+  takesQ(t)
+  t.foo()
+  t.bar()
 }
 
 // CHECK-LABEL: sil hidden @$s26specialize_self_conforming16callsTakesPWithPyyAA1P_pF : $@convention(thin) (@guaranteed any P) -> () {
diff --git a/test/SILOptimizer/static_atomics.swift b/test/SILOptimizer/static_atomics.swift
new file mode 100644
index 0000000000000..9ee6d23c9893e
--- /dev/null
+++ b/test/SILOptimizer/static_atomics.swift
@@ -0,0 +1,65 @@
+// RUN: %target-build-swift -parse-as-library -Xfrontend -disable-availability-checking -O %s -module-name=test -emit-sil | %FileCheck %s
+
+// RUN: %empty-directory(%t) 
+// RUN: %target-build-swift -parse-as-library -Xfrontend -disable-availability-checking -O -module-name=test %s -o %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s -check-prefix=CHECK-OUTPUT
+
+// REQUIRES: executable_test,swift_stdlib_no_asserts,optimized_stdlib
+// REQUIRES: synchronization
+// UNSUPPORTED: back_deployment_runtime
+
+import Synchronization
+
+
+struct TwoAtomics: ~Copyable {
+  let a: Atomic<UInt8>
+  let b: Atomic<UInt8>
+}
+
+// CHECK-LABEL: sil_global hidden @$s4test7atomic1AA10TwoAtomicsVSgvp : $Optional<TwoAtomics> = {
+var atomic1: TwoAtomics? = nil
+
+// CHECK-LABEL: sil_global hidden @$s4test7atomic2AA10TwoAtomicsVvp : $TwoAtomics = {
+let atomic2: TwoAtomics = TwoAtomics(a: Atomic(29), b: Atomic(30))
+
+// TODO: this is not initialized statically, because missing IRGen support
+var atomic3: TwoAtomics? = TwoAtomics(a: Atomic(27), b: Atomic(28))
+
+// CHECK-LABEL: sil_global hidden @$s4test5mutex15Synchronization5MutexVySiGvp : $Mutex<Int> = {
+let mutex = Mutex<Int>(123)
+
+@main
+struct Main {
+  static func main() {
+
+    precondition(atomic1 == nil)
+
+    // CHECK-OUTPUT: atomic2: 29 30
+    print("atomic2:", atomic2.a.load(ordering: .relaxed), atomic2.b.load(ordering: .relaxed))
+
+    // CHECK-OUTPUT: atomic3: 27 28
+    switch atomic3 {
+    case .some(let a):
+      print("atomic3:", a.a.load(ordering: .relaxed), a.b.load(ordering: .relaxed))
+    case .none:
+      break
+    }
+
+    atomic1 = TwoAtomics(a: Atomic(1), b: Atomic(2))
+
+    // CHECK-OUTPUT: atomic2: 29 30
+    print("atomic2:", atomic2.a.load(ordering: .relaxed), atomic2.b.load(ordering: .relaxed))
+
+
+    mutex.withLock {
+      $0 = $0 + 1
+    }
+
+    // CHECK-OUTPUT: mutex: 124
+    mutex.withLock {
+      print("mutex:", $0)
+    }
+  }
+}
+
+
diff --git a/test/SILOptimizer/static_init_globals.swift b/test/SILOptimizer/static_init_globals.swift
new file mode 100644
index 0000000000000..3d91ee07f66e6
--- /dev/null
+++ b/test/SILOptimizer/static_init_globals.swift
@@ -0,0 +1,32 @@
+// RUN: %target-swift-frontend %s -module-name=test -emit-sil | %FileCheck %s
+// RUN: %target-swift-frontend %s -O -module-name=test -emit-sil | %FileCheck %s --check-prefix=CHECK --check-prefix=OPT
+
+// REQUIRES: swift_stdlib_no_asserts,optimized_stdlib
+
+public struct GenS<T> {
+  var a: T
+  var b: T
+  var c: T
+  var d: T
+  var e: T
+  var f: T
+  var g: T
+  var h: T
+}
+
+public struct MyStruct {
+  // CHECK-LABEL: sil_global [let] @$s4test8MyStructV1rSnySiGvpZ : $Range<Int> = {
+  // CHECK-NEXT:    %0 = integer_literal $Builtin.Int{{[0-9]+}}, 1
+  // CHECK-NEXT:    %1 = struct $Int (%0)
+  // CHECK-NEXT:    %2 = integer_literal $Builtin.Int{{[0-9]+}}, 3
+  // CHECK-NEXT:    %3 = struct $Int (%2)
+  // CHECK-NEXT:    %initval = struct $Range<Int> (%1, %3)
+  // CHECK-NEXT:  }
+  public static let r: Range<Int> = 1 ..< 3
+
+  // OPT-LABEL: sil_global [let] @$s4test8MyStructV07genericC0AA4GenSVySiGvpZ : $GenS<Int> = {
+  // OPT:         %initval = struct $GenS
+  // OPT-NEXT:  }
+  public static let genericStruct = GenS(a: 1, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7, h: 8)
+}
+
diff --git a/test/SILOptimizer/static_inline_arrays.swift b/test/SILOptimizer/static_inline_arrays.swift
index 9009913c87c60..cdac4c4d07f66 100644
--- a/test/SILOptimizer/static_inline_arrays.swift
+++ b/test/SILOptimizer/static_inline_arrays.swift
@@ -7,6 +7,7 @@
 // RUN: %target-run %t/a.out | %FileCheck %s -check-prefix=CHECK-OUTPUT
 
 // REQUIRES: executable_test,optimized_stdlib
+// REQUIRES: OS=macosx || OS=linux-gnu || OS=windows-msvc
 // UNSUPPORTED: back_deployment_runtime
 
 extension InlineArray: Collection {
@@ -18,6 +19,16 @@ struct IntByte {
   let b: Int8
 }
 
+public struct ByteAndLargeArray {
+  let a: Int
+  let b: InlineArray<128, Int>
+}
+
+public struct ByteAndSmallArray {
+  let a: Int
+  let b: InlineArray<3, Int>
+}
+
 struct IntByteAndByte {
   let a: InlineArray<3, IntByte>
   let x: Int8
@@ -25,18 +36,21 @@ struct IntByteAndByte {
 
 struct S {
   // CHECK-LABEL: sil_global hidden [let] @$s4test1SV6simples11InlineArrayVy$2_SiGvpZ : $InlineArray<3, Int> = {
-  // CHECK:         %initval = vector
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         %initval = struct $InlineArray<3, Int> ([[V]])
   // CHECK:       }
   static let simple: InlineArray = [1, 2, 3]
 
   // CHECK-LABEL: sil_global hidden [let] @$s4test1SV12optionalIntss11InlineArrayVy$2_SiSgGvpZ : $InlineArray<3, Optional<Int>> = {
-  // CHECK:         %initval = vector
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         %initval = struct $InlineArray<3, Optional<Int>> ([[V]])
   // CHECK:       }
   static let optionalInts: InlineArray<_, Int?> = [10, 20, 30]
 
   // CHECK-LABEL: sil_global hidden [let] @$s4test1SV13optionalArrays06InlineC0Vy$2_SiGSgvpZ : $Optional<InlineArray<3, Int>> = {
   // CHECK:         [[V:%.*]] = vector
-  // CHECK:         %initval = enum $Optional<InlineArray<3, Int>>, #Optional.some!enumelt, [[V]]
+  // CHECK:         [[A:%.*]] = struct $InlineArray<3, Int> ([[V]])
+  // CHECK:         %initval = enum $Optional<InlineArray<3, Int>>, #Optional.some!enumelt, [[A]]
   // CHECK:       }
   static let optionalArray: InlineArray? = [1, 2, 3]
 
@@ -44,13 +58,15 @@ struct S {
   // CHECK:         [[S0:%.*]] = struct $IntByte
   // CHECK:         [[S1:%.*]] = struct $IntByte
   // CHECK:         [[S2:%.*]] = struct $IntByte
-  // CHECK:         %initval = vector ([[S0]], [[S1]], [[S2]])
+  // CHECK:         [[V:%.*]] = vector ([[S0]], [[S1]], [[S2]])
+  // CHECK:         %initval = struct $InlineArray<3, IntByte> ([[V]])
   // CHECK:       }
   static let intBytePairs: InlineArray<_, IntByte> = [IntByte(i: 1, b: 2), IntByte(i: 3, b: 4), IntByte(i: 5, b: 6)]
 
   // CHECK-LABEL: sil_global hidden [let] @$s4test1SV26optionalInlineArrayOfPairss0cD0Vy$2_AA7IntByteVGSgvpZ : $Optional<InlineArray<3, IntByte>> = {
   // CHECK:         [[V:%.*]] = vector
-  // CHECK:         %initval = enum $Optional<InlineArray<3, IntByte>>, #Optional.some!enumelt, [[V]]
+  // CHECK:         [[A:%.*]] = struct $InlineArray<3, IntByte> ([[V]])
+  // CHECK:         %initval = enum $Optional<InlineArray<3, IntByte>>, #Optional.some!enumelt, [[A]]
   // CHECK:       }
   static let optionalInlineArrayOfPairs: InlineArray<_, IntByte>? = [IntByte(i: 11, b: 12), IntByte(i: 13, b: 14), IntByte(i: 15, b: 16)]
 
@@ -58,23 +74,88 @@ struct S {
   // CHECK:         [[T0:%.*]] = tuple
   // CHECK:         [[T1:%.*]] = tuple
   // CHECK:         [[T2:%.*]] = tuple
-  // CHECK:         %initval = vector ([[T0]], [[T1]], [[T2]])
+  // CHECK:         [[V:%.*]] = vector ([[T0]], [[T1]], [[T2]])
+  // CHECK:         %initval = struct $InlineArray<3, (Int, Int)> ([[V]])
   // CHECK:       }
   static let tuples: InlineArray = [(10, 20), (30, 40), (50, 60)]
 
   // CHECK-LABEL: sil_global hidden [let] @$s4test1SV6nesteds11InlineArrayVy$2_AFy$1_SiGGvpZ : $InlineArray<3, InlineArray<2, Int>> = {
   // CHECK:         [[V0:%.*]] = vector
+  // CHECK:         [[A0:%.*]] = struct $InlineArray<2, Int> ([[V0]])
   // CHECK:         [[V1:%.*]] = vector
+  // CHECK:         [[A1:%.*]] = struct $InlineArray<2, Int> ([[V1]])
   // CHECK:         [[V2:%.*]] = vector
-  // CHECK:         %initval = vector ([[V0]], [[V1]], [[V2]])
+  // CHECK:         [[A2:%.*]] = struct $InlineArray<2, Int> ([[V2]])
+  // CHECK:         [[V:%.*]] = vector ([[A0]], [[A1]], [[A2]])
+  // CHECK:         %initval = struct $InlineArray<3, InlineArray<2, Int>> ([[V]])
   // CHECK:       }
   static let nested: InlineArray<3, InlineArray<2, Int>> = [[100, 200], [300, 400], [500, 600]]
 
   // CHECK-LABEL: sil_global hidden [let] @$s4test1SV010intByteAndC0AA03IntcdC0VvpZ : $IntByteAndByte = {
   // CHECK:         [[V:%.*]] = vector
-  // CHECK:         %initval = struct $IntByteAndByte ([[V]],
+  // CHECK:         [[A:%.*]] = struct $InlineArray<3, IntByte> ([[V]])
+  // CHECK:         %initval = struct $IntByteAndByte ([[A]],
   // CHECK:       }
   static let intByteAndByte = IntByteAndByte(a: [IntByte(i: 1, b: 2), IntByte(i: 3, b: 4), IntByte(i: 5, b: 6)], x: 27)
+
+  // CHECK-LABEL: sil_global hidden [let] @$s4test1SV14smallRepeatings11InlineArrayVy$4_SiGvpZ : $InlineArray<5, Int> = {
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         %initval = struct $InlineArray<5, Int> ([[V]])
+  // CHECK:       }
+  static let smallRepeating: InlineArray<5, Int> = .init(repeating: 26)
+
+  // CHECK-LABEL: sil_global hidden [let] @$s4test1SV14largeRepeatings11InlineArrayVy$127_SiGvpZ : $InlineArray<128, Int> = {
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         %initval = struct $InlineArray<128, Int> ([[V]])
+  // CHECK:       }
+  static let largeRepeating: InlineArray<128, Int> = .init(repeating: 28)
+
+  // CHECK-LABEL: sil_global hidden [let] @$s4test1SV20mediumRepeatingTuples11InlineArrayVy$31_Si_SbtGvpZ : $InlineArray<32, (Int, Bool)> = {
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         %initval = struct $InlineArray<32, (Int, Bool)> ([[V]])
+  // CHECK:       }
+  static let mediumRepeatingTuple: InlineArray<32, (Int, Bool)> = .init(repeating: (29, true))
+
+  // CHECK-LABEL: sil_global hidden [let] @$s4test1SV22inStructRepeatingSmallAA07ByteAndE5ArrayVvpZ : $ByteAndSmallArray = {
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         [[A:%.*]] = struct $InlineArray<3, Int> ([[V]])
+  // CHECK:         %initval = struct $ByteAndSmallArray ({{%[0-9]+}}, [[A]])
+  // CHECK:       }
+  static let inStructRepeatingSmall = ByteAndSmallArray(a: 31, b: [1, 2, 3])
+
+  // CHECK-LABEL: sil_global hidden [let] @$s4test1SV22inStructRepeatingLargeAA07ByteAndE5ArrayVvpZ : $ByteAndLargeArray = {
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         [[A:%.*]] = struct $InlineArray<128, Int> ([[V]])
+  // CHECK:         %initval = struct $ByteAndLargeArray ({{%[0-9]+}}, [[A]])
+  // CHECK:       }
+  static let inStructRepeatingLarge = ByteAndLargeArray(a: 32, b: InlineArray(repeating: 35))
+
+  // CHECK-LABEL: sil_global hidden [let] @$s4test1SV15nestedRepeatings11InlineArrayVy$1_AFy$2_SiGGvpZ : $InlineArray<2, InlineArray<3, Int>> = {
+  // CHECK:         vector
+  // CHECK:         vector
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         %initval = struct $InlineArray<2, InlineArray<3, Int>> ([[V]])
+  // CHECK:       }
+  static let nestedRepeating: InlineArray<2, InlineArray<3, Int>> = .init(repeating: .init(repeating: 33))
+
+  // CHECK-LABEL: sil_global hidden [let] @$s4test1SV20nestedLargeRepeatings11InlineArrayVy$39_AFy$49_SiGGvpZ : $InlineArray<40, InlineArray<50, Int>> = {
+  // CHECK:         %initval = struct $InlineArray<40, InlineArray<50, Int>>
+  // CHECK:       }
+  static let nestedLargeRepeating: InlineArray<40, InlineArray<50, Int>> = .init(repeating: .init(repeating: 34))
+
+  // CHECK-LABEL: sil_global hidden [let] @$s4test1SV22optionalRepeatingSmalls11InlineArrayVy$4_SiGSgvpZ : $Optional<InlineArray<5, Int>> = {
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         [[A:%.*]] = struct $InlineArray<5, Int> ([[V]])
+  // CHECK:         %initval = enum $Optional<InlineArray<5, Int>>, #Optional.some!enumelt, [[A]]
+  // CHECK:       }
+  static let optionalRepeatingSmall: InlineArray<5, Int>? = .init(repeating: 36)
+
+  // CHECK-LABEL: sil_global hidden [let] @$s4test1SV22optionalRepeatingLarges11InlineArrayVy$63_SiGSgvpZ : $Optional<InlineArray<64, Int>> = {
+  // CHECK:         [[V:%.*]] = vector
+  // CHECK:         [[A:%.*]] = struct $InlineArray<64, Int> ([[V]])
+  // CHECK:         %initval = enum $Optional<InlineArray<64, Int>>, #Optional.some!enumelt, [[A]]
+  // CHECK:       }
+  static let optionalRepeatingLarge: InlineArray<64, Int>? = .init(repeating: 37)
 }
 
 @main
@@ -103,6 +184,33 @@ struct Main {
 
     // CHECK-OUTPUT: intByteAndByte: a: [test.IntByte(i: 1, b: 2), test.IntByte(i: 3, b: 4), test.IntByte(i: 5, b: 6)], x: 27
     print("intByteAndByte: a: \(S.intByteAndByte.a.asArray), x: \(S.intByteAndByte.x)")
+
+    // CHECK-OUTPUT: smallRepeating: [26, 26, 26, 26, 26]
+    print("smallRepeating: \(S.smallRepeating.asArray)")
+
+    // CHECK-OUTPUT: largeRepeating: [{{(28, ){127}28}}]
+    print("largeRepeating: \(S.largeRepeating.asArray)")
+
+    // CHECK-OUTPUT: mediumRepeatingTuple: [{{(\(29, true\), ){31}\(29, true\)}}]
+    print("mediumRepeatingTuple: \(S.mediumRepeatingTuple.asArray)")
+
+    // CHECK-OUTPUT: inStructRepeatingSmall:  a: 31, b: [1, 2, 3]
+    print("inStructRepeatingSmall:  a: \(S.inStructRepeatingSmall.a), b: \(S.inStructRepeatingSmall.b.asArray)")
+
+    // CHECK-OUTPUT: inStructRepeatingLarge: a: 32, b: [{{(35, ){127}35}}]
+    print("inStructRepeatingLarge: a: \(S.inStructRepeatingLarge.a), b: \(S.inStructRepeatingLarge.b.asArray)")
+
+    // CHECK-OUTPUT: nestedRepeating: {{\[\[}}33, 33, 33], [33, 33, 33{{\]\]}}
+    print("nestedRepeating: \(S.nestedRepeating.map { $0.asArray })")
+
+    // CHECK-OUTPUT: nestedLargeRepeating: [{{(\[(34, ){49}34\], ){39}\[(34, ){49}34\]}}]
+    print("nestedLargeRepeating: \(S.nestedLargeRepeating.map { $0.asArray })")
+
+    // CHECK-OUTPUT: optionalRepeatingSmall: [36, 36, 36, 36, 36]
+    print("optionalRepeatingSmall: \(S.optionalRepeatingSmall!.asArray)")
+
+    // CHECK-OUTPUT: optionalRepeatingLarge: [{{(37, ){63}37}}]
+    print("optionalRepeatingLarge: \(S.optionalRepeatingLarge!.asArray)")
   }
 }
 
diff --git a/test/SILOptimizer/stdlib/Atomics.swift b/test/SILOptimizer/stdlib/Atomics.swift
index e20723abf9e67..43e3effecb212 100644
--- a/test/SILOptimizer/stdlib/Atomics.swift
+++ b/test/SILOptimizer/stdlib/Atomics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -O -Xllvm -sil-print-types -emit-sil -disable-availability-checking -enable-ossa-modules %s | %IRGenFileCheck %s
+// RUN: %target-swift-frontend -O -Xllvm -sil-print-types -emit-sil -disable-availability-checking %s | %IRGenFileCheck %s
 
 // REQUIRES: synchronization
 
@@ -13,7 +13,7 @@ func testInt(_: Int)
 
 // CHECK-LABEL: sil {{.*}} @localLoad {{.*}} {
 // CHECK:         [[ATOMIC:%.*]] = alloc_stack [lexical] [var_decl] $Atomic<Int>
-// CHECK:         [[ATOMIC_PTR:%.*]] = address_to_pointer [[ATOMIC]]
+// CHECK:         [[ATOMIC_PTR:%.*]] = builtin "addressOfRawLayout"<Atomic<Int>>([[ATOMIC]] : $*Atomic<Int>)
 // CHECK:         builtin "atomicload_monotonic_Int[[PTR_SIZE]]"([[ATOMIC_PTR]] : $Builtin.RawPointer)
 // CHECK:         dealloc_stack [[ATOMIC]] : $*Atomic<Int>
 // CHECK-LABEL: } // end sil function 'localLoad'
@@ -25,7 +25,7 @@ func localLoad() -> Int {
 
 // CHECK-LABEL: sil {{.*}} @localStore {{.*}} {
 // CHECK:         [[ATOMIC:%.*]] = alloc_stack [lexical] [var_decl] $Atomic<Int>
-// CHECK:         [[ATOMIC_PTR:%.*]] = address_to_pointer [[ATOMIC]]
+// CHECK:         [[ATOMIC_PTR:%.*]] = builtin "addressOfRawLayout"<Atomic<Int>>([[ATOMIC]] : $*Atomic<Int>)
 // CHECK:         builtin "atomicstore_release_Int[[PTR_SIZE]]"([[ATOMIC_PTR]] : $Builtin.RawPointer
 // CHECK:         dealloc_stack [[ATOMIC]] : $*Atomic<Int>
 // CHECK-LABEL: } // end sil function 'localStore'
@@ -37,7 +37,7 @@ func localStore() {
 
 // CHECK-LABEL: sil {{.*}} @localExchange {{.*}} {
 // CHECK:         [[ATOMIC:%.*]] = alloc_stack [lexical] [var_decl] $Atomic<Int>
-// CHECK:         [[ATOMIC_PTR:%.*]] = address_to_pointer [[ATOMIC]]
+// CHECK:         [[ATOMIC_PTR:%.*]] = builtin "addressOfRawLayout"<Atomic<Int>>([[ATOMIC]] : $*Atomic<Int>)
 // CHECK:         builtin "atomicrmw_xchg_acquire_Int[[PTR_SIZE]]"([[ATOMIC_PTR]] : $Builtin.RawPointer
 // CHECK:         dealloc_stack [[ATOMIC]] : $*Atomic<Int>
 // CHECK-LABEL: } // end sil function 'localExchange'
@@ -49,7 +49,7 @@ func localExchange() -> Int {
 
 // CHECK-LABEL: sil {{.*}} @localCompareExchange {{.*}} {
 // CHECK:         [[ATOMIC:%.*]] = alloc_stack [lexical] [var_decl] $Atomic<Int>
-// CHECK:         [[ATOMIC_PTR:%.*]] = address_to_pointer [[ATOMIC]]
+// CHECK:         [[ATOMIC_PTR:%.*]] = builtin "addressOfRawLayout"<Atomic<Int>>([[ATOMIC]] : $*Atomic<Int>)
 // CHECK:         builtin "cmpxchg_seqcst_seqcst_Int[[PTR_SIZE]]"([[ATOMIC_PTR]] : $Builtin.RawPointer
 // CHECK:         dealloc_stack [[ATOMIC]] : $*Atomic<Int>
 // CHECK-LABEL: } // end sil function 'localCompareExchange'
diff --git a/test/SILOptimizer/stdlib/Cell.swift b/test/SILOptimizer/stdlib/Cell.swift
index fefc37fc93d88..0b9ac2ecc422f 100644
--- a/test/SILOptimizer/stdlib/Cell.swift
+++ b/test/SILOptimizer/stdlib/Cell.swift
@@ -20,7 +20,7 @@ public struct Cell<T: ~Copyable>: ~Copyable {
 
   // CHECK-LABEL: sil {{.*}} @$s4CellAAVAARi_zrlEyAByxGxcfC : $@convention(method) <T where T : ~Copyable> (@in T, @thin Cell<T>.Type) -> @out Cell<T> {
   // CHECK:       bb0({{%.*}} : $*Cell<T>, [[VALUE:%.*]] : $*T, {{%.*}} : $@thin Cell<T>.Type):
-  // CHECK:         {{%.*}} = builtin "zeroInitializer"([[SELF:%.*]] : $*Cell<T>) : $()
+  // CHECK:         {{%.*}} = builtin "prepareInitialization"([[SELF:%.*]] : $*Cell<T>) : $()
   // CHECK-NEXT:    [[RAW_LAYOUT_ADDR:%.*]] = builtin "addressOfRawLayout"<Cell<T>>([[SELF]] : $*Cell<T>) : $Builtin.RawPointer
   // CHECK-NEXT:    [[POINTER:%.*]] = struct $UnsafeMutablePointer<T> ([[RAW_LAYOUT_ADDR]] : $Builtin.RawPointer)
   //                Calling 'UnsafeMutablePointer<T>.initialize(to:)'
diff --git a/test/SILOptimizer/string_optimization.swift b/test/SILOptimizer/string_optimization.swift
index e20a2370e9c40..410161abd79ce 100644
--- a/test/SILOptimizer/string_optimization.swift
+++ b/test/SILOptimizer/string_optimization.swift
@@ -1,5 +1,4 @@
 // RUN: %target-build-swift -O %s -module-name=test -Xfrontend -sil-verify-all -emit-sil | %FileCheck %s
-// RUN: %target-build-swift -O %s -module-name=test -Xfrontend -sil-verify-all -emit-sil -Xfrontend -enable-ossa-modules | %FileCheck %s
 
 // RUN: %empty-directory(%t) 
 // RUN: %target-build-swift -O -module-name=test %s -o %t/a.out
@@ -7,9 +6,6 @@
 
 // REQUIRES: executable_test,swift_stdlib_no_asserts
 // REQUIRES: swift_in_compiler
-// Test needs to be updated for 32bit.
-// rdar://74810823
-// UNSUPPORTED: PTRSIZE=32
 
 #if _runtime(_ObjC)
 import Foundation
diff --git a/test/SILOptimizer/swift-unit-tests.sil b/test/SILOptimizer/swift-unit-tests.sil
deleted file mode 100644
index 9be5265eee382..0000000000000
--- a/test/SILOptimizer/swift-unit-tests.sil
+++ /dev/null
@@ -1,4 +0,0 @@
-// RUN: %target-sil-opt %s -run-unit-tests -o /dev/null
-
-// REQUIRES: swift_in_compiler
-
diff --git a/test/SILOptimizer/temp_rvalue_opt.sil b/test/SILOptimizer/temp_rvalue_opt.sil
index 5f994a1e54283..c7924fa07b6b1 100644
--- a/test/SILOptimizer/temp_rvalue_opt.sil
+++ b/test/SILOptimizer/temp_rvalue_opt.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -temp-rvalue-opt | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -temp-rvalue-elimination | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 
@@ -827,3 +827,18 @@ bb0:
   return %12
 }
 
+// CHECK-LABEL: sil @store_to_temp :
+// CHECK:         %1 = load %0
+// CHECK-NEXT:    return %1
+// CHECK-LABEL: } // end sil function 'store_to_temp'
+sil @store_to_temp : $@convention(thin) (@in_guaranteed Klass) -> @owned Klass {
+bb0(%0 : $*Klass):
+  %1 = load %0
+  %2 = alloc_stack $Klass
+  store %1 to %2
+  %4 = load %2
+  destroy_addr %2
+  dealloc_stack %2
+  return %4
+}
+
diff --git a/test/SILOptimizer/temp_rvalue_opt_ossa.sil b/test/SILOptimizer/temp_rvalue_opt_ossa.sil
index 720753726f7d3..3dc34339b59d2 100644
--- a/test/SILOptimizer/temp_rvalue_opt_ossa.sil
+++ b/test/SILOptimizer/temp_rvalue_opt_ossa.sil
@@ -1,4 +1,5 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -update-borrowed-from -temp-rvalue-opt | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -update-borrowed-from -temp-rvalue-elimination | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-OPT
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -update-borrowed-from -mandatory-temp-rvalue-elimination | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-ONONE
 
 // REQUIRES: swift_in_compiler
 
@@ -108,8 +109,33 @@ bb0(%0 : $*GS<B>, %1 : $*GS<B>):
   return %9999 : $()
 }
 
+// CHECK-LABEL: sil [ossa] @multi_block :
+// CHECK-NOT:     alloc_stack
+// CHECK-LABEL: } // end sil function 'multi_block'
+sil [ossa] @multi_block : $@convention(thin) <B> (@in_guaranteed GS<B>, @inout GS<B>) -> () {
+bb0(%0 : $*GS<B>, %1 : $*GS<B>):
+  %2 = struct_element_addr %0 : $*GS<B>, #GS._value
+  %3 = load [trivial] %2 : $*Builtin.Int64
+  %4 = alloc_stack $GS<B>
+  br bb1
+
+bb1:
+  copy_addr %1 to [init] %4 : $*GS<B>
+  %6 = struct_element_addr %4 : $*GS<B>, #GS._value
+  %7 = load [trivial] %6 : $*Builtin.Int64
+  %8 = builtin "cmp_slt_Int64"(%3 : $Builtin.Int64, %7 : $Builtin.Int64) : $Builtin.Int1
+  br bb2
+
+bb2:
+  destroy_addr %4 : $*GS<B>
+  dealloc_stack %4 : $*GS<B>
+  %9999 = tuple()
+  return %9999 : $()
+}
+
 // CHECK-LABEL: sil [ossa] @copy_from_temp
 // CHECK:      bb0(%0 : $*GS<B>, %1 : $*GS<B>, %2 : $Builtin.Int64):
+// CHECK-ONONE-NEXT:   debug_step
 // CHECK-NEXT:   builtin
 // CHECK-NEXT:   copy_addr %1 to [init] %0 : $*GS<B>
 // CHECK-NEXT:   tuple
@@ -128,6 +154,7 @@ bb0(%0 : $*GS<B>, %1 : $*GS<B>, %2 : $Builtin.Int64):
 
 // CHECK-LABEL: sil [ossa] @copy_back_to_src
 // CHECK:      bb0(%0 : $*GS<B>, %1 : $*GS<B>):
+// CHECK-ONONE-NEXT:   debug_step
 // CHECK-NEXT:   struct_element_addr %1
 // CHECK-NEXT:   load
 // CHECK-NEXT:   builtin
@@ -186,6 +213,7 @@ bb0(%0 : $*Builtin.NativeObject, %1 : @owned $Builtin.NativeObject):
 
 // CHECK-LABEL: sil [ossa] @copy_with_take_and_copy_from_src
 // CHECK:       bb0({{.*}}):
+// CHECK-ONONE-NEXT:   debug_step
 // CHECK-NEXT:    destroy_addr %0
 // CHECK-NEXT:    copy_addr [take] %1 to [init] %0
 // CHECK-NEXT:    tuple
@@ -315,6 +343,7 @@ bb1:
 // CHECK-LABEL: sil [ossa] @store_after_load
 // CHECK:      bb0(%0 : $*GS<B>, %1 : $*GS<B>, %2 : $Builtin.Int64):
 // CHECK-NEXT:   [[A1:%.*]] = struct_element_addr %1
+// CHECK-ONONE-NEXT:   debug_step
 // CHECK-NEXT:   [[A2:%.*]] = struct_element_addr %1
 // CHECK-NEXT:   load [trivial] [[A2]]
 // CHECK-NEXT:   store %2 to [trivial] [[A1]]
@@ -339,6 +368,7 @@ bb0(%0 : $*GS<B>, %1 : $*GS<B>, %2 : $Builtin.Int64):
 // CHECK-LABEL: sil [ossa] @store_after_two_loads
 // CHECK:      bb0(%0 : $*GS<B>, %1 : $*GS<B>, %2 : $Builtin.Int64):
 // CHECK-NEXT:   [[A1:%.*]] = struct_element_addr %1
+// CHECK-ONONE-NEXT:   debug_step
 // CHECK-NEXT:   [[A2:%.*]] = struct_element_addr %1
 // CHECK-NEXT:   load [trivial] [[A2]]
 // CHECK-NEXT:   load [trivial] [[A2]]
@@ -452,6 +482,7 @@ bb0(%0 : $*GS<B>, %1 : $*GS<B>, %2 : $Builtin.Int64):
 // Test temp RValue elimination on switches.
 // CHECK-LABEL: sil [ossa] @rvalueSwitch
 // CHECK:      bb1:
+// CHECK-ONONE-NEXT:   debug_step
 // CHECK-NEXT:   struct_element_addr %1
 // CHECK-NEXT:   load
 // CHECK-NOT: alloc_stack $UnfoldSequence
@@ -583,6 +614,8 @@ bb0(%0 : $*Klass):
 // CHECK-LABEL: sil [ossa] @non_overlapping_lifetime : $@convention(thin) (@in Klass) -> () {
 // CHECK:      bb0([[ARG:%.*]] : $*Klass):
 // CHECK-NEXT:   [[TMP:%.*]] = alloc_stack $Klass
+// CHECK-ONONE-NEXT:   debug_step
+// CHECK-ONONE-NEXT:   debug_step
 // CHECK-NEXT:   copy_addr [[ARG]] to [init] [[TMP]]
 // CHECK-NEXT:   destroy_addr [[ARG]]
 // CHECK:        apply %{{[0-9]*}}([[TMP]])
@@ -810,24 +843,6 @@ bb0(%0 : $*GS<Builtin.NativeObject>):
   return %v : $()
 }
 
-// Make sure that when we convert the load [take] to a load [copy], we hoist the
-// load of src /before/ the destroy of %0.
-// CHECK-LABEL: sil [ossa] @hoist_load_copy_to_src_copy_addr_site : $@convention(thin) (@owned GS<Builtin.NativeObject>) -> @owned GS<Builtin.NativeObject> {
-// CHECK: bb0([[ARG:%.*]] : @owned
-// CHECK:   apply {{%.*}}([[ARG]])
-// CHECK:   return [[ARG]]
-// CHECK: } // end sil function 'hoist_load_copy_to_src_copy_addr_site'
-sil [ossa] @hoist_load_copy_to_src_copy_addr_site : $@convention(thin) (@owned GS<Builtin.NativeObject>) -> @owned GS<Builtin.NativeObject> {
-bb0(%0 : @owned $GS<Builtin.NativeObject>):
-  %f = function_ref @use_gsbase_builtinnativeobject : $@convention(thin) (@guaranteed GS<Builtin.NativeObject>) -> ()
-  %stk = alloc_stack $GS<Builtin.NativeObject>
-  store %0 to [init] %stk : $*GS<Builtin.NativeObject>
-  %obj = load [take] %stk : $*GS<Builtin.NativeObject>
-  dealloc_stack %stk : $*GS<Builtin.NativeObject>
-  apply %f(%obj) : $@convention(thin) (@guaranteed GS<Builtin.NativeObject>) -> ()
-  return %obj : $GS<Builtin.NativeObject>
-}
-
 // CHECK-LABEL: sil [ossa] @dont_optimize_with_load_in_different_block
 // CHECK:   [[STK:%[0-9]+]] = alloc_stack
 // CHECK:   copy_addr %0 to [init] [[STK]]
@@ -1026,394 +1041,6 @@ bb3:
 // Store Tests //
 /////////////////
 
-// We do not support this today while we are bringing up store support.
-//
-// CHECK-LABEL: sil [ossa] @store_rvalue_simple
-// CHECK: alloc_stack
-// CHECK-LABEL: } // end sil function 'store_rvalue_simple'
-sil [ossa] @store_rvalue_simple : $@convention(thin) (@in_guaranteed GS<Klass>, @owned GS<Klass>) -> () {
-bb0(%0 : $*GS<Klass>, %1 : @owned $GS<Klass>):
-  %2 = struct_element_addr %0 : $*GS<Klass>, #GS._value
-  %3 = load [trivial] %2 : $*Builtin.Int64
-  %4 = alloc_stack $GS<Klass>
-  store %1 to [init] %4 : $*GS<Klass>
-  %6 = struct_element_addr %4 : $*GS<Klass>, #GS._value
-  %7 = load [trivial] %6 : $*Builtin.Int64
-  %8 = builtin "cmp_slt_Int64"(%3 : $Builtin.Int64, %7 : $Builtin.Int64) : $Builtin.Int1
-  destroy_addr %4 : $*GS<Klass>
-  dealloc_stack %4 : $*GS<Klass>
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil [ossa] @store_copy_from_temp :
-// CHECK:       bb0([[RESULT:%.*]] : $*GS<Klass>, [[ARG0:%.*]] : @owned $GS<Klass>,
-// CHECK:          builtin
-// CHECK:          [[ARG0_COPY:%.*]] = copy_value [[ARG0]]
-// CHECK:          store [[ARG0_COPY]] to [init] [[RESULT]]
-// CHECK:          destroy_value [[ARG0]]
-// CHECK: } // end sil function 'store_copy_from_temp'
-sil [ossa] @store_copy_from_temp : $@convention(thin) (@owned GS<Klass>, Builtin.Int64) -> @out GS<Klass> {
-bb0(%0 : $*GS<Klass>, %1 : @owned $GS<Klass>, %2 : $Builtin.Int64):
-  %4 = alloc_stack $GS<Klass>
-  store %1 to [init] %4 : $*GS<Klass>
-  %8 = builtin "cmp_slt_Int64"(%2 : $Builtin.Int64, %2 : $Builtin.Int64) : $Builtin.Int1
-  copy_addr %4 to [init] %0 : $*GS<Klass>
-  destroy_addr %4 : $*GS<Klass>
-  dealloc_stack %4 : $*GS<Klass>
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// We do not support this today.
-//
-// CHECK-LABEL: sil [ossa] @store_take_from_temp :
-// CHECK: alloc_stack
-// CHECK: } // end sil function 'store_take_from_temp'
-sil [ossa] @store_take_from_temp : $@convention(thin) (@inout Klass, @owned GS<Klass>) -> () {
-bb0(%0 : $*Klass, %1 : @owned $GS<Klass>):
-  %4 = alloc_stack $GS<Klass>
-  store %1 to [init] %4 : $*GS<Klass>
-  %7 = struct_element_addr %4 : $*GS<Klass>, #GS._base
-  copy_addr [take] %7 to %0 : $*Klass
-  dealloc_stack %4 : $*GS<Klass>
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil [ossa] @store_load_in_wrong_block :
-// CHECK:   alloc_stack
-// CHECK: } // end sil function 'store_load_in_wrong_block'
-sil [ossa] @store_load_in_wrong_block : $@convention(thin) (@guaranteed GS<Klass>) -> () {
-bb0(%0 : @guaranteed $GS<Klass>):
-  %4 = alloc_stack $GS<Klass>
-  %1 = copy_value %0 : $GS<Klass>
-  store %1 to [init] %4 : $*GS<Klass>
-  %6 = struct_element_addr %4 : $*GS<Klass>, #GS._value
-  br bb1
-
-bb1:
-  %7 = load [trivial] %6 : $*Builtin.Int64
-  %8 = builtin "cmp_slt_Int64"(%7 : $Builtin.Int64, %7 : $Builtin.Int64) : $Builtin.Int1
-  destroy_addr %4 : $*GS<Klass>
-  dealloc_stack %4 : $*GS<Klass>
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil [ossa] @store_projection_in_wrong_block :
-// CHECK:       bb0(%0 : @guaranteed $GS<Klass>):
-// CHECK:         alloc_stack
-// CHECK:       } // end sil function 'store_projection_in_wrong_block'
-sil [ossa] @store_projection_in_wrong_block : $@convention(thin) (@guaranteed GS<Klass>) -> () {
-bb0(%0 : @guaranteed $GS<Klass>):
-  %4 = alloc_stack $GS<Klass>
-  %0a = copy_value %0 : $GS<Klass>
-  store %0a to [init] %4 : $*GS<Klass>
-  br bb1
-
-bb1:
-  %6 = struct_element_addr %4 : $*GS<Klass>, #GS._value
-  %7 = load [trivial] %6 : $*Builtin.Int64
-  %8 = builtin "cmp_slt_Int64"(%7 : $Builtin.Int64, %7 : $Builtin.Int64) : $Builtin.Int1
-  destroy_addr %4 : $*GS<Klass>
-  dealloc_stack %4 : $*GS<Klass>
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: sil [ossa] @store_store_after_load :
-// CHECK: alloc_stack
-// CHECK: } // end sil function 'store_store_after_load'
-sil [ossa] @store_store_after_load : $@convention(thin) (@guaranteed GS<Klass>, Builtin.Int64) -> () {
-bb0(%1 : @guaranteed $GS<Klass>, %2 : $Builtin.Int64):
-  %3 = struct_extract %1 : $GS<Klass>, #GS._value
-  %4 = alloc_stack $GS<Klass>
-  %1a = copy_value %1 : $GS<Klass>
-  store %1a to [init] %4 : $*GS<Klass>
-  %6 = struct_element_addr %4 : $*GS<Klass>, #GS._value
-  %7 = load [trivial] %6 : $*Builtin.Int64
-  %8 = builtin "cmp_slt_Int64"(%7 : $Builtin.Int64, %7 : $Builtin.Int64) : $Builtin.Int1
-  destroy_addr %4 : $*GS<Klass>
-  dealloc_stack %4 : $*GS<Klass>
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// TODO: We do not support this today due to the in_guaranteed parameter. Maybe
-// instead we use store_borrow just around the call site?
-//
-// Make sure that we can eliminate temporaries passed via a temporary rvalue to
-// an @guaranteed function.
-//
-// CHECK-LABEL: sil [ossa] @store_inguaranteed_no_result : $@convention(thin) (@guaranteed Klass) -> () {
-// CHECK: bb0([[ARG:%.*]] : @guaranteed $Klass):
-// CHECK: alloc_stack
-// CHECK: } // end sil function 'store_inguaranteed_no_result'
-sil [ossa] @store_inguaranteed_no_result : $@convention(thin) (@guaranteed Klass) -> () {
-bb0(%0 : @guaranteed $Klass):
-  %1 = alloc_stack $Klass
-  %0a = copy_value %0 : $Klass
-  store %0a to [init] %1 : $*Klass
-  %5 = function_ref @inguaranteed_user_without_result : $@convention(thin) (@in_guaranteed Klass) -> ()
-  %6 = apply %5(%1) : $@convention(thin) (@in_guaranteed Klass) -> ()
-  destroy_addr %1 : $*Klass
-  dealloc_stack %1 : $*Klass
-  %9 = tuple ()
-  return %9 : $()
-}
-
-// We do not support this today since we need to make it so that we can use
-// store_borrow to pass to the in_guaranteed function.
-//
-// CHECK-LABEL: sil [ossa] @store_try_apply_argument : $@convention(thin) (@guaranteed Klass) -> () {
-// CHECK: alloc_stack
-// CHECK: } // end sil function 'store_try_apply_argument'
-sil [ossa] @store_try_apply_argument : $@convention(thin) (@guaranteed Klass) -> () {
-bb0(%0 : @guaranteed $Klass):
-  %1 = alloc_stack $Klass
-  %0copy = copy_value %0 : $Klass
-  store %0copy to [init] %1 : $*Klass
-  %5 = function_ref @throwing_function : $@convention(thin) (@in_guaranteed Klass) -> ((), @error Error)
-  try_apply %5(%1) : $@convention(thin) (@in_guaranteed Klass) -> ((), @error Error), normal bb1, error bb2
-
-bb1(%r : $()):
-  br bb3
-
-bb2(%e : $Error):
-  br bb3
-
-bb3:
-  destroy_addr %1 : $*Klass
-  dealloc_stack %1 : $*Klass
-  %9 = tuple ()
-  return %9 : $()
-}
-
-// TODO: We need to support using store_borrow to shrink the lifetime here.
-//
-// Make sure that we can eliminate temporaries passed via a temporary rvalue to
-// an @guaranteed function.
-//
-// CHECK-LABEL: sil [ossa] @store_inguaranteed_with_result : $@convention(thin) (@owned Klass) -> () {
-// CHECK: bb0([[ARG:%.*]] : @owned $Klass):
-// CHECK: alloc_stack
-// CHECK: alloc_stack
-// CHECK: } // end sil function 'store_inguaranteed_with_result'
-sil [ossa] @store_inguaranteed_with_result : $@convention(thin) (@owned Klass) -> () {
-bb0(%0 : @owned $Klass):
-  %1 = alloc_stack $Klass
-  %1a = alloc_stack $Klass
-  store %0 to [init] %1 : $*Klass
-  %5 = function_ref @inguaranteed_user_with_result : $@convention(thin) (@in_guaranteed Klass) -> @out Klass
-  %6 = apply %5(%1a, %1) : $@convention(thin) (@in_guaranteed Klass) -> @out Klass
-  destroy_addr %1a : $*Klass
-  destroy_addr %1 : $*Klass
-  dealloc_stack %1a : $*Klass
-  dealloc_stack %1 : $*Klass
-  %9 = tuple ()
-  return %9 : $()
-}
-
-// TODO: Once we are able to use store_borrow to shrink lifetimes, we will have
-// no alloc_stack in this function.
-//
-// CHECK-LABEL: sil [ossa] @store_non_overlapping_lifetime : $@convention(thin) (@owned Klass) -> () {
-// CHECK: = alloc_stack
-// CHECK-NOT: = alloc_stack
-// CHECK: } // end sil function 'store_non_overlapping_lifetime'
-sil [ossa] @store_non_overlapping_lifetime : $@convention(thin) (@owned Klass) -> () {
-bb0(%0 : @owned $Klass):
-  %1a = alloc_stack $Klass
-
-  %1 = alloc_stack $Klass
-  %2 = alloc_stack $Klass
-  %0a = copy_value %0 : $Klass
-  store %0a to [init] %2 : $*Klass
-  copy_addr [take] %2 to [init] %1 : $*Klass
-  dealloc_stack %2 : $*Klass
-  copy_addr %1 to [init] %1a : $*Klass
-  destroy_value %0 : $Klass
-  destroy_addr %1 : $*Klass
-  dealloc_stack %1 : $*Klass
-
-  %3 = function_ref @inguaranteed_user_without_result : $@convention(thin) (@in_guaranteed Klass) -> ()
-  apply %3(%1a) : $@convention(thin) (@in_guaranteed Klass) -> ()
-  destroy_addr %1a : $*Klass
-  dealloc_stack %1a : $*Klass
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-sil [ossa] @store_$createKlass : $@convention(thin) () -> @out Klass
-sil [ossa] @store_$appendKlass : $@convention(method) (@guaranteed Klass, @inout Klass) -> ()
-
-// TODO: With time we should be able to shrink the lifetime of the first
-// argument here with time.
-//
-// CHECK-LABEL: sil [ossa] @store_overlapping_lifetime_in_function_all : $@convention(thin) () -> @out Klass {
-// CHECK: [[S1:%.*]] = alloc_stack $Klass
-// CHECK: [[S2:%.*]] = alloc_stack $Klass
-// CHECK: [[S1_LOADED:%.*]] = load [copy] [[S1]]
-// CHECK: store [[S1_LOADED]] to [init] [[S2]]
-// CHECK: apply {{%.*}}([[S2]], [[S1]])
-// CHECK: } // end sil function 'store_overlapping_lifetime_in_function_all'
-sil [ossa] @store_overlapping_lifetime_in_function_all : $@convention(thin) () -> @out Klass {
-bb0(%0 : $*Klass):
-  %1 = alloc_stack $Klass
-  %2 = function_ref @$createKlass : $@convention(thin) () -> @out Klass
-  %3 = apply %2(%1) : $@convention(thin) () -> @out Klass
-  %4 = alloc_stack $Klass
-  %2a = load [copy] %1 : $*Klass
-  store %2a to [init] %4 : $*Klass
-  %6 = function_ref @$appendKlass : $@convention(method) (@in_guaranteed Klass, @inout Klass) -> ()
-  %7 = apply %6(%4, %1) : $@convention(method) (@in_guaranteed Klass, @inout Klass) -> ()
-  destroy_addr %4 : $*Klass
-  dealloc_stack %4 : $*Klass
-  copy_addr [take] %1 to [init] %0 : $*Klass
-  dealloc_stack %1 : $*Klass
-  %12 = tuple ()
-  return %12 : $()
-}
-
-sil [ossa] @store_getP : $@convention(thin) () -> @out Optional<P>
-sil [ossa] @store_takeGuaranteedObj : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
-
-// Now that we support ossa, eliminate the alloc_stack and change the load
-// [take] to a load [copy] in the process.
-//
-// CHECK-LABEL: sil [ossa] @store_copyWithLoadRelease : $@convention(thin) (@guaranteed Builtin.NativeObject) -> () {
-// CHECK: bb0(%0 : @guaranteed $Builtin.NativeObject):
-// CHECK-NOT: alloc_stack
-// CHECK-LABEL: } // end sil function 'store_copyWithLoadRelease'
-sil [ossa] @store_copyWithLoadRelease : $@convention(thin) (@guaranteed Builtin.NativeObject) -> () {
-bb0(%0 : @guaranteed $Builtin.NativeObject):
-  %stk = alloc_stack $Builtin.NativeObject
-  %0copy = copy_value %0 : $Builtin.NativeObject
-  store %0copy to [init] %stk : $*Builtin.NativeObject
-  %obj = load [take] %stk : $*Builtin.NativeObject
-  %f = function_ref @takeGuaranteedObj : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
-  %call = apply %f(%obj) : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
-  destroy_value %obj : $Builtin.NativeObject
-  dealloc_stack %stk : $*Builtin.NativeObject
-  %v = tuple ()
-  return %v : $()
-}
-
-// Remove a copy that is released via a load. Leave the load [take] alone since
-// our copy_addr is taking from source.
-//
-// CHECK-LABEL: sil [ossa] @store_takeWithLoadRelease : $@convention(thin) (@owned Builtin.NativeObject) -> () {
-// CHECK-NOT: alloc_stack
-// CHECK-LABEL: } // end sil function 'store_takeWithLoadRelease'
-sil [ossa] @store_takeWithLoadRelease : $@convention(thin) (@owned Builtin.NativeObject) -> () {
-bb0(%0 : @owned $Builtin.NativeObject):
-  %stk = alloc_stack $Builtin.NativeObject
-  store %0 to [init] %stk : $*Builtin.NativeObject
-  %obj = load [take] %stk : $*Builtin.NativeObject
-  %f = function_ref @takeGuaranteedObj : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
-  %call = apply %f(%obj) : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
-  destroy_value %obj : $Builtin.NativeObject
-  dealloc_stack %stk : $*Builtin.NativeObject
-  %v = tuple ()
-  return %v : $()
-}
-
-// Do not remove a copy that is released via a load of a projection. This is not
-// the pattern from SILGen that we are targeting, so we reduce the state space by banning the pattern.
-//
-// CHECK-LABEL: sil [ossa] @store_takeWithLoadReleaseOfProjection : $@convention(thin) (@owned GS<Builtin.NativeObject>) -> () {
-// CHECK: alloc_stack
-// CHECK: } // end sil function 'store_takeWithLoadReleaseOfProjection'
-sil [ossa] @store_takeWithLoadReleaseOfProjection : $@convention(thin) (@owned GS<Builtin.NativeObject>) -> () {
-bb0(%0 : @owned $GS<Builtin.NativeObject>):
-  %stk = alloc_stack $GS<Builtin.NativeObject>
-  store %0 to [init] %stk : $*GS<Builtin.NativeObject>
-  %proj = struct_element_addr %stk : $*GS<Builtin.NativeObject>, #GS._base
-  %obj = load [take] %proj : $*Builtin.NativeObject
-  %f = function_ref @takeGuaranteedObj : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
-  %call = apply %f(%obj) : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
-  destroy_value %obj : $Builtin.NativeObject
-  dealloc_stack %stk : $*GS<Builtin.NativeObject>
-  %v = tuple ()
-  return %v : $()
-}
-
-// CHECK-LABEL: sil [ossa] @test_optimize_store_of_enum1
-// CHECK-NOT:      alloc_stack
-// CHECK:       } // end sil function 'test_optimize_store_of_enum1'
-sil [ossa] @test_optimize_store_of_enum1 : $@convention(method) <Element> (@guaranteed Optional<Klass>) -> () {
-bb0(%0 : @guaranteed $Optional<Klass>):
-  %1 = copy_value %0 : $Optional<Klass>
-  %32 = alloc_stack $Optional<Klass>
-  store %1 to [init] %32 : $*Optional<Klass>
-  switch_enum %0 : $Optional<Klass>, case #Optional.some!enumelt: bb6, case #Optional.none!enumelt: bb5
-
-bb5:
-  dealloc_stack %32 : $*Optional<Klass>
-  br bb7
-
-bb6(%50 : @guaranteed $Klass):
-  %53 = load [take] %32 : $*Optional<Klass>
-  destroy_value %53 : $Optional<Klass>
-  dealloc_stack %32 : $*Optional<Klass>
-  br bb7
-
-bb7:
-  %r = tuple ()
-  return %r : $()
-}
-
-// CHECK-LABEL: sil [ossa] @test_optimize_store_of_enum2
-// CHECK-NOT:      alloc_stack
-// CHECK:       } // end sil function 'test_optimize_store_of_enum2'
-sil [ossa] @test_optimize_store_of_enum2 : $@convention(method) <Element> (@owned Optional<Klass>) -> () {
-bb0(%0 : @owned $Optional<Klass>):
-  %1 = copy_value %0 : $Optional<Klass>
-  %32 = alloc_stack $Optional<Klass>
-  store %0 to [init] %32 : $*Optional<Klass>
-  switch_enum %1 : $Optional<Klass>, case #Optional.some!enumelt: bb6, case #Optional.none!enumelt: bb5
-
-bb5:
-  dealloc_stack %32 : $*Optional<Klass>
-  br bb7
-
-bb6(%50 : @owned $Klass):
-  %53 = load [take] %32 : $*Optional<Klass>
-  destroy_value %53 : $Optional<Klass>
-  destroy_value %50 : $Klass
-  dealloc_stack %32 : $*Optional<Klass>
-  br bb7
-
-bb7:
-  %r = tuple ()
-  return %r : $()
-}
-
-// CHECK-LABEL: sil [ossa] @store_of_enum_must_be_in_same_block
-// CHECK-NOT:     alloc_stack
-// CHECK:       } // end sil function 'store_of_enum_must_be_in_same_block'
-sil [ossa] @store_of_enum_must_be_in_same_block : $@convention(method) <Element> (@guaranteed Optional<Klass>) -> () {
-bb0(%0 : @guaranteed $Optional<Klass>):
-  %32 = alloc_stack $Optional<Klass>
-  switch_enum %0 : $Optional<Klass>, case #Optional.some!enumelt: bb6, case #Optional.none!enumelt: bb5
-
-bb5:
-  dealloc_stack %32 : $*Optional<Klass>
-  br bb7
-
-bb6(%50 : @guaranteed $Klass):
-  %1 = copy_value %0 : $Optional<Klass>
-  store %1 to [init] %32 : $*Optional<Klass>
-  %53 = load [take] %32 : $*Optional<Klass>
-  destroy_value %53 : $Optional<Klass>
-  dealloc_stack %32 : $*Optional<Klass>
-  br bb7
-
-bb7:
-  %r = tuple ()
-  return %r : $()
-}
 ////////////////////////////////////////
 // Unchecked Take Enum Data Addr Inst //
 ////////////////////////////////////////
@@ -1479,43 +1106,6 @@ bb0(%0 : $*Klass):
   return %9999 : $()
 }
 
-// CHECK-LABEL: sil [ossa] @eliminate_fix_lifetime_on_dest_store : $@convention(thin) (@inout Klass) -> () {
-// CHECK-NOT: alloc_stack
-// CHECK:  [[VALUE:%.*]] = load [copy] %0
-// CHECK-NEXT: fix_lifetime [[VALUE]]
-// CHECK-NEXT: destroy_value [[VALUE]]
-// CHECK-NOT: alloc_stack
-// CHECK: } // end sil function 'eliminate_fix_lifetime_on_dest_store'
-sil [ossa] @eliminate_fix_lifetime_on_dest_store : $@convention(thin) (@inout Klass) -> () {
-bb0(%0 : $*Klass):
-  %2 = load [copy] %0 : $*Klass
-  %3 = alloc_stack $Klass
-  store %2 to [init] %3 : $*Klass
-  fix_lifetime %3 : $*Klass
-  destroy_addr %3 : $*Klass
-  dealloc_stack %3 : $*Klass
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// Check that we don't crash with this.
-// CHECK-LABEL: sil [ossa] @unhandled_user : $@convention(thin) (@owned Klass) -> @owned Klass {
-// CHECK:   alloc_stack
-// CHECK:   store
-// CHECK:   begin_access
-// CHECK:   load
-// CHECK: } // end sil function 'unhandled_user'
-sil [ossa] @unhandled_user : $@convention(thin) (@owned Klass) -> @owned Klass {
-bb0(%0 : @owned $Klass):
-  %5 = alloc_stack $Klass
-  store %0 to [init] %5 : $*Klass
-  %104 = begin_access [read] [static] %5 : $*Klass
-  %105 = load [take] %104 : $*Klass
-  end_access %104 : $*Klass
-  dealloc_stack %5 : $*Klass
-  return %105 : $Klass
-}
-
 // CHECK-LABEL: sil [ossa] @test_yield
 // CHECK:   [[TA:%[0-9]+]] = ref_tail_addr
 // CHECK-NOT: copy_addr
@@ -1789,9 +1379,10 @@ bb1(%6 : @guaranteed $Klass):
 // Lexical alloc_stacks can still be eliminated if their sources are guaranteed
 // function arguments (because those are lexical and have a live range that
 // contains the live range of the value stored into the alloc stack).
-// CHECK-LABEL: sil [ossa] @copy_addr__lexical_alloc_stack_temporary__guaranteed_function_arg : {{.*}} {
-// CHECK-NOT:     alloc_stack
-// CHECK-LABEL: } // end sil function 'copy_addr__lexical_alloc_stack_temporary__guaranteed_function_arg'
+// CHECK-LABEL:   sil [ossa] @copy_addr__lexical_alloc_stack_temporary__guaranteed_function_arg : {{.*}} {
+// CHECK-OPT-NOT:   alloc_stack
+// CHECK-ONONE:     alloc_stack
+// CHECK-LABEL:   } // end sil function 'copy_addr__lexical_alloc_stack_temporary__guaranteed_function_arg'
 sil [ossa] @copy_addr__lexical_alloc_stack_temporary__guaranteed_function_arg : $@convention(thin) (@guaranteed OtherClass) -> () {
 entry(%instance : @guaranteed $OtherClass):
   %field_ptr = ref_element_addr %instance : $OtherClass, #OtherClass.klass
@@ -1803,9 +1394,10 @@ entry(%instance : @guaranteed $OtherClass):
   return %retval : $()
 }
 
-// CHECK-LABEL: sil [ossa] @copy_addr__lexical_alloc_stack_temporary_in_guaranteed_function_arg : {{.*}} {
-// CHECK-NOT:     alloc_stack
-// CHECK-LABEL: } // end sil function 'copy_addr__lexical_alloc_stack_temporary_in_guaranteed_function_arg'
+// CHECK-LABEL:   sil [ossa] @copy_addr__lexical_alloc_stack_temporary_in_guaranteed_function_arg : {{.*}} {
+// CHECK-OPT-NOT:   alloc_stack
+// CHECK-ONONE:     alloc_stack
+// CHECK-LABEL:   } // end sil function 'copy_addr__lexical_alloc_stack_temporary_in_guaranteed_function_arg'
 sil [ossa] @copy_addr__lexical_alloc_stack_temporary_in_guaranteed_function_arg : $@convention(thin) (@in_guaranteed Klass) -> () {
 entry(%instance : $*Klass):
   %addr = alloc_stack [lexical] $Klass
@@ -1816,11 +1408,24 @@ entry(%instance : $*Klass):
   return %retval : $()
 }
 
-// Lexical alloc_stacks can't be eliminated even if their source is a function
-// argument if that function argument is inout.
-// CHECK-LABEL: sil [ossa] @copy_addr__lexical_alloc_stack_temporary__inout_function_arg : {{.*}} {
-// CHECK:         alloc_stack [lexical]
-// CHECK-LABEL: } // end sil function 'copy_addr__lexical_alloc_stack_temporary__inout_function_arg'
+// CHECK-LABEL:   sil [ossa] @copy_addr__vardecl_alloc_stack_temporary_in_guaranteed_function_arg : {{.*}} {
+// CHECK-OPT-NOT:   alloc_stack
+// CHECK-ONONE:     alloc_stack
+// CHECK-LABEL:   } // end sil function 'copy_addr__vardecl_alloc_stack_temporary_in_guaranteed_function_arg'
+sil [ossa] @copy_addr__vardecl_alloc_stack_temporary_in_guaranteed_function_arg : $@convention(thin) (@in_guaranteed Klass) -> () {
+entry(%instance : $*Klass):
+  %addr = alloc_stack [var_decl] $Klass
+  copy_addr %instance to [init] %addr : $*Klass
+  destroy_addr %addr : $*Klass
+  dealloc_stack %addr : $*Klass
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL:   sil [ossa] @copy_addr__lexical_alloc_stack_temporary__inout_function_arg : {{.*}} {
+// CHECK-OPT-NOT:   alloc_stack
+// CHECK-ONONE:     alloc_stack
+// CHECK-LABEL:   } // end sil function 'copy_addr__lexical_alloc_stack_temporary__inout_function_arg'
 sil [ossa] @copy_addr__lexical_alloc_stack_temporary__inout_function_arg : $@convention(thin) (@inout NonTrivialStruct) -> () {
 entry(%instance : $*NonTrivialStruct):
   %field_ptr = struct_element_addr %instance : $*NonTrivialStruct, #NonTrivialStruct.val
@@ -1893,3 +1498,125 @@ bb0(%0 : $*P):
   %15 = tuple ()
   return %15
 }
+
+// CHECK-LABEL: sil [ossa] @store_to_temp :
+// CHECK:       bb0(%0 : $*Klass):
+// CHECK-ONONE-NEXT:   debug_step
+// CHECK-NEXT:    [[L:%.*]] = load [copy] %0
+// CHECK-NEXT:    return [[L]]
+// CHECK-LABEL: } // end sil function 'store_to_temp'
+sil [ossa] @store_to_temp : $@convention(thin) (@in_guaranteed Klass) -> @owned Klass {
+bb0(%0 : $*Klass):
+  %1 = load [copy] %0
+  %2 = alloc_stack $Klass
+  store %1 to [init] %2
+  %4 = load [copy] %2
+  destroy_addr %2
+  dealloc_stack %2
+  return %4
+}
+
+// CHECK-LABEL: sil [ossa] @store_to_temp_take :
+// CHECK:       bb0(%0 : $*Klass):
+// CHECK-ONONE-NEXT:   debug_step
+// CHECK-NEXT:    [[L:%.*]] = load [copy] %0
+// CHECK-NEXT:    destroy_addr %0
+// CHECK-NEXT:    return [[L]]
+// CHECK-LABEL: } // end sil function 'store_to_temp_take'
+sil [ossa] @store_to_temp_take : $@convention(thin) (@in Klass) -> @owned Klass {
+bb0(%0 : $*Klass):
+  %1 = load [take] %0
+  %2 = alloc_stack $Klass
+  store %1 to [init] %2
+  %4 = load [copy] %2
+  destroy_addr %2
+  dealloc_stack %2
+  return %4
+}
+
+// CHECK-LABEL: sil [ossa] @store_to_temp_trivial :
+// CHECK:       bb0(%0 : $*Int):
+// CHECK-ONONE-NEXT:   debug_step
+// CHECK-NEXT:    [[L:%.*]] = load [trivial] %0
+// CHECK-NEXT:    return [[L]]
+// CHECK-LABEL: } // end sil function 'store_to_temp_trivial'
+sil [ossa] @store_to_temp_trivial : $@convention(thin) (@in_guaranteed Int) -> @owned Int {
+bb0(%0 : $*Int):
+  %1 = load [trivial] %0
+  %2 = alloc_stack $Int
+  store %1 to [trivial] %2
+  %4 = load [trivial] %2
+  destroy_addr %2
+  dealloc_stack %2
+  return %4
+}
+
+// CHECK-LABEL: sil [ossa] @store_with_early_destroy_of_src :
+// CHECK:         alloc_stack
+// CHECK-NEXT:    store %1
+// CHECK-LABEL: } // end sil function 'store_with_early_destroy_of_src'
+sil [ossa] @store_with_early_destroy_of_src : $@convention(thin) (@in Klass) -> @owned Klass {
+bb0(%0 : $*Klass):
+  %1 = load [copy] %0
+  fix_lifetime %0
+  destroy_addr %0
+  %2 = alloc_stack $Klass
+  store %1 to [init] %2
+  %4 = load [copy] %2
+  destroy_addr %2
+  dealloc_stack %2
+  return %4
+}
+
+// CHECK-LABEL: sil [ossa] @store_with_load_in_different_block :
+// CHECK:         alloc_stack
+// CHECK-NEXT:    store %1
+// CHECK-LABEL: } // end sil function 'store_with_load_in_different_block'
+sil [ossa] @store_with_load_in_different_block : $@convention(thin) (@in Klass) -> @owned Klass {
+bb0(%0 : $*Klass):
+  %1 = load [copy] %0
+  br bb1
+bb1:
+  fix_lifetime %0
+  destroy_addr %0
+  br bb2
+bb2:
+  %2 = alloc_stack $Klass
+  store %1 to [init] %2
+  %4 = load [copy] %2
+  destroy_addr %2
+  dealloc_stack %2
+  return %4
+}
+
+// CHECK-LABEL: sil [ossa] @store_with_load_with_multiple_uses :
+// CHECK:         fix_lifetime
+// CHECK:         alloc_stack
+// CHECK-NEXT:    store %1
+// CHECK-LABEL: } // end sil function 'store_with_load_with_multiple_uses'
+sil [ossa] @store_with_load_with_multiple_uses : $@convention(thin) (@in_guaranteed Klass) -> @owned Klass {
+bb0(%0 : $*Klass):
+  %1 = load [copy] %0
+  fix_lifetime %1
+  %2 = alloc_stack $Klass
+  store %1 to [init] %2
+  %4 = load [copy] %2
+  destroy_addr %2
+  dealloc_stack %2
+  return %4
+}
+
+// CHECK-LABEL: sil [ossa] @store_without_load :
+// CHECK:         alloc_stack
+// CHECK-NEXT:    store %0
+// CHECK-LABEL: } // end sil function 'store_without_load'
+sil [ossa] @store_without_load : $@convention(thin) (@owned Klass) -> @owned Klass {
+bb0(%0 : @owned $Klass):
+  %2 = alloc_stack $Klass
+  store %0 to [init] %2
+  %4 = load [copy] %2
+  destroy_addr %2
+  dealloc_stack %2
+  return %4
+}
+
diff --git a/test/SILOptimizer/temp_rvalue_rle.sil b/test/SILOptimizer/temp_rvalue_rle.sil
new file mode 100644
index 0000000000000..7566115ec4809
--- /dev/null
+++ b/test/SILOptimizer/temp_rvalue_rle.sil
@@ -0,0 +1,508 @@
+// RUN: %target-sil-opt %s -redundant-load-elimination -deadobject-elim | %FileCheck %s
+
+sil_stage canonical
+
+import Builtin
+import Swift
+
+//===----------------------------------------------------------------------===//
+//      Tests eliminating stores to temporary "r-values", which were
+//      originally handled by TempRValueOpt.
+//===----------------------------------------------------------------------===//
+
+struct GS<Base> {
+  var _base: Base
+  var _value: Builtin.Int64
+}
+
+class Klass {
+  @_hasStorage var i: Int
+  init()
+}
+
+class OtherClass {
+  var klass: Klass
+}
+
+struct Two {
+  var a: Klass
+  var b: Klass
+}
+
+struct NonTrivialStruct {
+  var val:Klass
+}
+
+public enum FakeOptional<T> {
+  case none
+  case some(T)
+}
+
+struct MOS: ~Copyable {}
+
+protocol P {
+  func foo()
+}
+
+sil [ossa] @getKlass : $@convention(thin) () -> @owned Klass
+sil [ossa] @getNonTrivialStruct : $@convention(thin) () -> @owned NonTrivialStruct
+sil [ossa] @getMOS : $@convention(thin) () -> @owned MOS
+
+sil @unknown : $@convention(thin) () -> ()
+sil [readonly] [ossa] @read_only_coroutine : $@yield_once @convention(thin) () -> @yields @in_guaranteed P
+
+sil [ossa] @guaranteed_user : $@convention(thin) (@guaranteed Klass) -> ()
+sil [ossa] @guaranteed_user_with_result : $@convention(thin) (@guaranteed Klass) -> @out Klass
+sil [ossa] @inguaranteed_user_without_result_NTS : $@convention(thin) (@in_guaranteed NonTrivialStruct) -> ()
+sil [ossa] @inguaranteed_user_without_result_MOS : $@convention(thin) (@in_guaranteed MOS) -> ()
+
+sil @use_gsbase_builtinnativeobject : $@convention(thin) (@guaranteed GS<Builtin.NativeObject>) -> ()
+sil @inguaranteed_user_without_result : $@convention(thin) (@in_guaranteed Klass) -> ()
+sil @throwing_function : $@convention(thin) (@in_guaranteed Klass) -> ((), @error Error)
+sil @inguaranteed_user_with_result : $@convention(thin) (@in_guaranteed Klass) -> @out Klass
+sil @$createKlass : $@convention(thin) () -> @out Klass
+sil @$appendKlass : $@convention(method) (@in_guaranteed Klass, @inout Klass) -> ()
+sil @takeGuaranteedObj : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+
+// Make sure that when we convert the load [take] to a load [copy], we hoist the
+// load of src /before/ the destroy of %0.
+// CHECK-LABEL: sil [ossa] @hoist_load_copy_to_src_copy_addr_site : $@convention(thin) (@owned GS<Builtin.NativeObject>) -> @owned GS<Builtin.NativeObject> {
+// CHECK: bb0([[ARG:%.*]] : @owned
+// CHECK:   apply {{%.*}}([[ARG]])
+// CHECK:   return [[ARG]]
+// CHECK: } // end sil function 'hoist_load_copy_to_src_copy_addr_site'
+sil [ossa] @hoist_load_copy_to_src_copy_addr_site : $@convention(thin) (@owned GS<Builtin.NativeObject>) -> @owned GS<Builtin.NativeObject> {
+bb0(%0 : @owned $GS<Builtin.NativeObject>):
+  %f = function_ref @use_gsbase_builtinnativeobject : $@convention(thin) (@guaranteed GS<Builtin.NativeObject>) -> ()
+  %stk = alloc_stack $GS<Builtin.NativeObject>
+  store %0 to [init] %stk : $*GS<Builtin.NativeObject>
+  %obj = load [take] %stk : $*GS<Builtin.NativeObject>
+  dealloc_stack %stk : $*GS<Builtin.NativeObject>
+  apply %f(%obj) : $@convention(thin) (@guaranteed GS<Builtin.NativeObject>) -> ()
+  return %obj : $GS<Builtin.NativeObject>
+}
+
+// We do not support this today while we are bringing up store support.
+//
+// CHECK-LABEL: sil [ossa] @store_rvalue_simple
+// CHECK: alloc_stack
+// CHECK-LABEL: } // end sil function 'store_rvalue_simple'
+sil [ossa] @store_rvalue_simple : $@convention(thin) (@in_guaranteed GS<Klass>, @owned GS<Klass>) -> () {
+bb0(%0 : $*GS<Klass>, %1 : @owned $GS<Klass>):
+  %2 = struct_element_addr %0 : $*GS<Klass>, #GS._value
+  %3 = load [trivial] %2 : $*Builtin.Int64
+  %4 = alloc_stack $GS<Klass>
+  store %1 to [init] %4 : $*GS<Klass>
+  %6 = struct_element_addr %4 : $*GS<Klass>, #GS._value
+  %7 = load [trivial] %6 : $*Builtin.Int64
+  %8 = builtin "cmp_slt_Int64"(%3 : $Builtin.Int64, %7 : $Builtin.Int64) : $Builtin.Int1
+  destroy_addr %4 : $*GS<Klass>
+  dealloc_stack %4 : $*GS<Klass>
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @store_copy_from_temp :
+// CHECK:       bb0([[RESULT:%.*]] : $*GS<Klass>, [[ARG0:%.*]] : @owned $GS<Klass>,
+// CHECK:          [[ARG0_COPY:%.*]] = copy_value [[ARG0]]
+// CHECK:          builtin
+// CHECK:          store [[ARG0_COPY]] to [init] [[RESULT]]
+// CHECK: } // end sil function 'store_copy_from_temp'
+sil [ossa] @store_copy_from_temp : $@convention(thin) (@owned GS<Klass>, Builtin.Int64) -> @out GS<Klass> {
+bb0(%0 : $*GS<Klass>, %1 : @owned $GS<Klass>, %2 : $Builtin.Int64):
+  %4 = alloc_stack $GS<Klass>
+  store %1 to [init] %4 : $*GS<Klass>
+  %8 = builtin "cmp_slt_Int64"(%2 : $Builtin.Int64, %2 : $Builtin.Int64) : $Builtin.Int1
+  copy_addr %4 to [init] %0 : $*GS<Klass>
+  destroy_addr %4 : $*GS<Klass>
+  dealloc_stack %4 : $*GS<Klass>
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @store_take_from_temp :
+// CHECK:         ([[S1:%.*]], [[S2:%.*]]) = destructure_struct %1
+// CHECK:         store [[S1]] to [assign] %0
+// CHECK:       } // end sil function 'store_take_from_temp'
+sil [ossa] @store_take_from_temp : $@convention(thin) (@inout Klass, @owned GS<Klass>) -> () {
+bb0(%0 : $*Klass, %1 : @owned $GS<Klass>):
+  %4 = alloc_stack $GS<Klass>
+  store %1 to [init] %4 : $*GS<Klass>
+  %7 = struct_element_addr %4 : $*GS<Klass>, #GS._base
+  copy_addr [take] %7 to %0 : $*Klass
+  dealloc_stack %4 : $*GS<Klass>
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @store_load_in_differnt_block :
+// CHECK-NOT:     alloc_stack
+// CHECK: } // end sil function 'store_load_in_differnt_block'
+sil [ossa] @store_load_in_differnt_block : $@convention(thin) (@guaranteed GS<Klass>) -> () {
+bb0(%0 : @guaranteed $GS<Klass>):
+  %4 = alloc_stack $GS<Klass>
+  %1 = copy_value %0 : $GS<Klass>
+  store %1 to [init] %4 : $*GS<Klass>
+  %6 = struct_element_addr %4 : $*GS<Klass>, #GS._value
+  br bb1
+
+bb1:
+  %7 = load [trivial] %6 : $*Builtin.Int64
+  %8 = builtin "cmp_slt_Int64"(%7 : $Builtin.Int64, %7 : $Builtin.Int64) : $Builtin.Int1
+  destroy_addr %4 : $*GS<Klass>
+  dealloc_stack %4 : $*GS<Klass>
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @store_projection_in_different_block :
+// CHECK:       bb0(%0 : @guaranteed $GS<Klass>):
+// CHECK-NOT:     alloc_stack
+// CHECK:       } // end sil function 'store_projection_in_different_block'
+sil [ossa] @store_projection_in_different_block : $@convention(thin) (@guaranteed GS<Klass>) -> () {
+bb0(%0 : @guaranteed $GS<Klass>):
+  %4 = alloc_stack $GS<Klass>
+  %0a = copy_value %0 : $GS<Klass>
+  store %0a to [init] %4 : $*GS<Klass>
+  br bb1
+
+bb1:
+  %6 = struct_element_addr %4 : $*GS<Klass>, #GS._value
+  %7 = load [trivial] %6 : $*Builtin.Int64
+  %8 = builtin "cmp_slt_Int64"(%7 : $Builtin.Int64, %7 : $Builtin.Int64) : $Builtin.Int1
+  destroy_addr %4 : $*GS<Klass>
+  dealloc_stack %4 : $*GS<Klass>
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @store_store_after_load :
+// CHECK-NOT:     alloc_stack
+// CHECK:       } // end sil function 'store_store_after_load'
+sil [ossa] @store_store_after_load : $@convention(thin) (@guaranteed GS<Klass>, Builtin.Int64) -> () {
+bb0(%1 : @guaranteed $GS<Klass>, %2 : $Builtin.Int64):
+  %3 = struct_extract %1 : $GS<Klass>, #GS._value
+  %4 = alloc_stack $GS<Klass>
+  %1a = copy_value %1 : $GS<Klass>
+  store %1a to [init] %4 : $*GS<Klass>
+  %6 = struct_element_addr %4 : $*GS<Klass>, #GS._value
+  %7 = load [trivial] %6 : $*Builtin.Int64
+  %8 = builtin "cmp_slt_Int64"(%7 : $Builtin.Int64, %7 : $Builtin.Int64) : $Builtin.Int1
+  destroy_addr %4 : $*GS<Klass>
+  dealloc_stack %4 : $*GS<Klass>
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// TODO: We do not support this today due to the in_guaranteed parameter. Maybe
+// instead we use store_borrow just around the call site?
+//
+// Make sure that we can eliminate temporaries passed via a temporary rvalue to
+// an @guaranteed function.
+//
+// CHECK-LABEL: sil [ossa] @store_inguaranteed_no_result : $@convention(thin) (@guaranteed Klass) -> () {
+// CHECK: bb0([[ARG:%.*]] : @guaranteed $Klass):
+// CHECK: alloc_stack
+// CHECK: } // end sil function 'store_inguaranteed_no_result'
+sil [ossa] @store_inguaranteed_no_result : $@convention(thin) (@guaranteed Klass) -> () {
+bb0(%0 : @guaranteed $Klass):
+  %1 = alloc_stack $Klass
+  %0a = copy_value %0 : $Klass
+  store %0a to [init] %1 : $*Klass
+  %5 = function_ref @inguaranteed_user_without_result : $@convention(thin) (@in_guaranteed Klass) -> ()
+  %6 = apply %5(%1) : $@convention(thin) (@in_guaranteed Klass) -> ()
+  destroy_addr %1 : $*Klass
+  dealloc_stack %1 : $*Klass
+  %9 = tuple ()
+  return %9 : $()
+}
+
+// We do not support this today since we need to make it so that we can use
+// store_borrow to pass to the in_guaranteed function.
+//
+// CHECK-LABEL: sil [ossa] @store_try_apply_argument : $@convention(thin) (@guaranteed Klass) -> () {
+// CHECK: alloc_stack
+// CHECK: } // end sil function 'store_try_apply_argument'
+sil [ossa] @store_try_apply_argument : $@convention(thin) (@guaranteed Klass) -> () {
+bb0(%0 : @guaranteed $Klass):
+  %1 = alloc_stack $Klass
+  %0copy = copy_value %0 : $Klass
+  store %0copy to [init] %1 : $*Klass
+  %5 = function_ref @throwing_function : $@convention(thin) (@in_guaranteed Klass) -> ((), @error Error)
+  try_apply %5(%1) : $@convention(thin) (@in_guaranteed Klass) -> ((), @error Error), normal bb1, error bb2
+
+bb1(%r : $()):
+  br bb3
+
+bb2(%e : $Error):
+  br bb3
+
+bb3:
+  destroy_addr %1 : $*Klass
+  dealloc_stack %1 : $*Klass
+  %9 = tuple ()
+  return %9 : $()
+}
+
+// TODO: We need to support using store_borrow to shrink the lifetime here.
+//
+// Make sure that we can eliminate temporaries passed via a temporary rvalue to
+// an @guaranteed function.
+//
+// CHECK-LABEL: sil [ossa] @store_inguaranteed_with_result : $@convention(thin) (@owned Klass) -> () {
+// CHECK: bb0([[ARG:%.*]] : @owned $Klass):
+// CHECK: alloc_stack
+// CHECK: alloc_stack
+// CHECK: } // end sil function 'store_inguaranteed_with_result'
+sil [ossa] @store_inguaranteed_with_result : $@convention(thin) (@owned Klass) -> () {
+bb0(%0 : @owned $Klass):
+  %1 = alloc_stack $Klass
+  %1a = alloc_stack $Klass
+  store %0 to [init] %1 : $*Klass
+  %5 = function_ref @inguaranteed_user_with_result : $@convention(thin) (@in_guaranteed Klass) -> @out Klass
+  %6 = apply %5(%1a, %1) : $@convention(thin) (@in_guaranteed Klass) -> @out Klass
+  destroy_addr %1a : $*Klass
+  destroy_addr %1 : $*Klass
+  dealloc_stack %1a : $*Klass
+  dealloc_stack %1 : $*Klass
+  %9 = tuple ()
+  return %9 : $()
+}
+
+// TODO: Once we are able to use store_borrow to shrink lifetimes, we will have
+// no alloc_stack in this function.
+//
+// CHECK-LABEL: sil [ossa] @store_non_overlapping_lifetime : $@convention(thin) (@owned Klass) -> () {
+// CHECK:         [[S:%.*]] = alloc_stack
+// CHECK:         [[C1:%.*]] = copy_value %0
+// CHECK:         [[C2:%.*]] = copy_value [[C1]]
+// CHECK:         store [[C2]] to [init] [[S]]
+// CHECK: } // end sil function 'store_non_overlapping_lifetime'
+sil [ossa] @store_non_overlapping_lifetime : $@convention(thin) (@owned Klass) -> () {
+bb0(%0 : @owned $Klass):
+  %1a = alloc_stack $Klass
+
+  %1 = alloc_stack $Klass
+  %2 = alloc_stack $Klass
+  %0a = copy_value %0 : $Klass
+  store %0a to [init] %2 : $*Klass
+  copy_addr [take] %2 to [init] %1 : $*Klass
+  dealloc_stack %2 : $*Klass
+  copy_addr %1 to [init] %1a : $*Klass
+  destroy_value %0 : $Klass
+  destroy_addr %1 : $*Klass
+  dealloc_stack %1 : $*Klass
+
+  %3 = function_ref @inguaranteed_user_without_result : $@convention(thin) (@in_guaranteed Klass) -> ()
+  apply %3(%1a) : $@convention(thin) (@in_guaranteed Klass) -> ()
+  destroy_addr %1a : $*Klass
+  dealloc_stack %1a : $*Klass
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+sil [ossa] @store_$createKlass : $@convention(thin) () -> @out Klass
+sil [ossa] @store_$appendKlass : $@convention(method) (@guaranteed Klass, @inout Klass) -> ()
+
+// TODO: With time we should be able to shrink the lifetime of the first
+// argument here with time.
+//
+// CHECK-LABEL: sil [ossa] @store_overlapping_lifetime_in_function_all : $@convention(thin) () -> @out Klass {
+// CHECK: [[S1:%.*]] = alloc_stack $Klass
+// CHECK: [[S2:%.*]] = alloc_stack $Klass
+// CHECK: [[S1_LOADED:%.*]] = load [copy] [[S1]]
+// CHECK: store [[S1_LOADED]] to [init] [[S2]]
+// CHECK: apply {{%.*}}([[S2]], [[S1]])
+// CHECK: } // end sil function 'store_overlapping_lifetime_in_function_all'
+sil [ossa] @store_overlapping_lifetime_in_function_all : $@convention(thin) () -> @out Klass {
+bb0(%0 : $*Klass):
+  %1 = alloc_stack $Klass
+  %2 = function_ref @$createKlass : $@convention(thin) () -> @out Klass
+  %3 = apply %2(%1) : $@convention(thin) () -> @out Klass
+  %4 = alloc_stack $Klass
+  %2a = load [copy] %1 : $*Klass
+  store %2a to [init] %4 : $*Klass
+  %6 = function_ref @$appendKlass : $@convention(method) (@in_guaranteed Klass, @inout Klass) -> ()
+  %7 = apply %6(%4, %1) : $@convention(method) (@in_guaranteed Klass, @inout Klass) -> ()
+  destroy_addr %4 : $*Klass
+  dealloc_stack %4 : $*Klass
+  copy_addr [take] %1 to [init] %0 : $*Klass
+  dealloc_stack %1 : $*Klass
+  %12 = tuple ()
+  return %12 : $()
+}
+
+sil [ossa] @store_getP : $@convention(thin) () -> @out Optional<P>
+sil [ossa] @store_takeGuaranteedObj : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+
+// Now that we support ossa, eliminate the alloc_stack and change the load
+// [take] to a load [copy] in the process.
+//
+// CHECK-LABEL: sil [ossa] @store_copyWithLoadRelease : $@convention(thin) (@guaranteed Builtin.NativeObject) -> () {
+// CHECK: bb0(%0 : @guaranteed $Builtin.NativeObject):
+// CHECK-NOT: alloc_stack
+// CHECK-LABEL: } // end sil function 'store_copyWithLoadRelease'
+sil [ossa] @store_copyWithLoadRelease : $@convention(thin) (@guaranteed Builtin.NativeObject) -> () {
+bb0(%0 : @guaranteed $Builtin.NativeObject):
+  %stk = alloc_stack $Builtin.NativeObject
+  %0copy = copy_value %0 : $Builtin.NativeObject
+  store %0copy to [init] %stk : $*Builtin.NativeObject
+  %obj = load [take] %stk : $*Builtin.NativeObject
+  %f = function_ref @takeGuaranteedObj : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+  %call = apply %f(%obj) : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+  destroy_value %obj : $Builtin.NativeObject
+  dealloc_stack %stk : $*Builtin.NativeObject
+  %v = tuple ()
+  return %v : $()
+}
+
+// Remove a copy that is released via a load. Leave the load [take] alone since
+// our copy_addr is taking from source.
+//
+// CHECK-LABEL: sil [ossa] @store_takeWithLoadRelease : $@convention(thin) (@owned Builtin.NativeObject) -> () {
+// CHECK-NOT: alloc_stack
+// CHECK-LABEL: } // end sil function 'store_takeWithLoadRelease'
+sil [ossa] @store_takeWithLoadRelease : $@convention(thin) (@owned Builtin.NativeObject) -> () {
+bb0(%0 : @owned $Builtin.NativeObject):
+  %stk = alloc_stack $Builtin.NativeObject
+  store %0 to [init] %stk : $*Builtin.NativeObject
+  %obj = load [take] %stk : $*Builtin.NativeObject
+  %f = function_ref @takeGuaranteedObj : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+  %call = apply %f(%obj) : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+  destroy_value %obj : $Builtin.NativeObject
+  dealloc_stack %stk : $*Builtin.NativeObject
+  %v = tuple ()
+  return %v : $()
+}
+
+// CHECK-LABEL: sil [ossa] @store_takeWithLoadReleaseOfProjection : $@convention(thin) (@owned GS<Builtin.NativeObject>) -> () {
+// CHECK:         ([[S1:%.*]], [[S2:%.*]]) = destructure_struct %0
+// CHECK:         apply %{{[0-9]+}}([[S1]])
+// CHECK: } // end sil function 'store_takeWithLoadReleaseOfProjection'
+sil [ossa] @store_takeWithLoadReleaseOfProjection : $@convention(thin) (@owned GS<Builtin.NativeObject>) -> () {
+bb0(%0 : @owned $GS<Builtin.NativeObject>):
+  %stk = alloc_stack $GS<Builtin.NativeObject>
+  store %0 to [init] %stk : $*GS<Builtin.NativeObject>
+  %proj = struct_element_addr %stk : $*GS<Builtin.NativeObject>, #GS._base
+  %obj = load [take] %proj : $*Builtin.NativeObject
+  %f = function_ref @takeGuaranteedObj : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+  %call = apply %f(%obj) : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+  destroy_value %obj : $Builtin.NativeObject
+  dealloc_stack %stk : $*GS<Builtin.NativeObject>
+  %v = tuple ()
+  return %v : $()
+}
+
+// We don't support liferange exits currently
+//
+// CHECK-LABEL: sil [ossa] @test_optimize_store_of_enum1
+// CHECK:      alloc_stack
+// CHECK:       } // end sil function 'test_optimize_store_of_enum1'
+sil [ossa] @test_optimize_store_of_enum1 : $@convention(method) <Element> (@guaranteed Optional<Klass>) -> () {
+bb0(%0 : @guaranteed $Optional<Klass>):
+  %1 = copy_value %0 : $Optional<Klass>
+  %32 = alloc_stack $Optional<Klass>
+  store %1 to [init] %32 : $*Optional<Klass>
+  switch_enum %0 : $Optional<Klass>, case #Optional.some!enumelt: bb6, case #Optional.none!enumelt: bb5
+
+bb5:
+  dealloc_stack %32 : $*Optional<Klass>
+  br bb7
+
+bb6(%50 : @guaranteed $Klass):
+  %53 = load [take] %32 : $*Optional<Klass>
+  destroy_value %53 : $Optional<Klass>
+  dealloc_stack %32 : $*Optional<Klass>
+  br bb7
+
+bb7:
+  %r = tuple ()
+  return %r : $()
+}
+
+// We don't support liferange exits currently
+//
+// CHECK-LABEL: sil [ossa] @test_optimize_store_of_enum2
+// CHECK:         alloc_stack
+// CHECK:       } // end sil function 'test_optimize_store_of_enum2'
+sil [ossa] @test_optimize_store_of_enum2 : $@convention(method) <Element> (@owned Optional<Klass>) -> () {
+bb0(%0 : @owned $Optional<Klass>):
+  %1 = copy_value %0 : $Optional<Klass>
+  %32 = alloc_stack $Optional<Klass>
+  store %0 to [init] %32 : $*Optional<Klass>
+  switch_enum %1 : $Optional<Klass>, case #Optional.some!enumelt: bb6, case #Optional.none!enumelt: bb5
+
+bb5:
+  dealloc_stack %32 : $*Optional<Klass>
+  br bb7
+
+bb6(%50 : @owned $Klass):
+  %53 = load [take] %32 : $*Optional<Klass>
+  destroy_value %53 : $Optional<Klass>
+  destroy_value %50 : $Klass
+  dealloc_stack %32 : $*Optional<Klass>
+  br bb7
+
+bb7:
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [ossa] @store_of_enum_must_be_in_same_block
+// CHECK-NOT:     alloc_stack
+// CHECK:       } // end sil function 'store_of_enum_must_be_in_same_block'
+sil [ossa] @store_of_enum_must_be_in_same_block : $@convention(method) <Element> (@guaranteed Optional<Klass>) -> () {
+bb0(%0 : @guaranteed $Optional<Klass>):
+  %32 = alloc_stack $Optional<Klass>
+  switch_enum %0 : $Optional<Klass>, case #Optional.some!enumelt: bb6, case #Optional.none!enumelt: bb5
+
+bb5:
+  dealloc_stack %32 : $*Optional<Klass>
+  br bb7
+
+bb6(%50 : @guaranteed $Klass):
+  %1 = copy_value %0 : $Optional<Klass>
+  store %1 to [init] %32 : $*Optional<Klass>
+  %53 = load [take] %32 : $*Optional<Klass>
+  destroy_value %53 : $Optional<Klass>
+  dealloc_stack %32 : $*Optional<Klass>
+  br bb7
+
+bb7:
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil [ossa] @eliminate_fix_lifetime_on_dest_store : $@convention(thin) (@inout Klass) -> () {
+// CHECK-NOT: alloc_stack
+// CHECK: } // end sil function 'eliminate_fix_lifetime_on_dest_store'
+sil [ossa] @eliminate_fix_lifetime_on_dest_store : $@convention(thin) (@inout Klass) -> () {
+bb0(%0 : $*Klass):
+  %2 = load [copy] %0 : $*Klass
+  %3 = alloc_stack $Klass
+  store %2 to [init] %3 : $*Klass
+  fix_lifetime %3 : $*Klass
+  destroy_addr %3 : $*Klass
+  dealloc_stack %3 : $*Klass
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// Check that we don't crash with this.
+// CHECK-LABEL: sil [ossa] @unhandled_user : $@convention(thin) (@owned Klass) -> @owned Klass {
+// CHECK:   alloc_stack
+// CHECK:   store
+// CHECK:   begin_access
+// CHECK:   load
+// CHECK: } // end sil function 'unhandled_user'
+sil [ossa] @unhandled_user : $@convention(thin) (@owned Klass) -> @owned Klass {
+bb0(%0 : @owned $Klass):
+  %5 = alloc_stack $Klass
+  store %0 to [init] %5 : $*Klass
+  %104 = begin_access [read] [static] %5 : $*Klass
+  %105 = load [take] %104 : $*Klass
+  end_access %104 : $*Klass
+  dealloc_stack %5 : $*Klass
+  return %105 : $Klass
+}
+
diff --git a/test/SILOptimizer/templvalueopt.sil b/test/SILOptimizer/templvalueopt.sil
index fd4c42fde5e9c..d767bca5d6ab9 100644
--- a/test/SILOptimizer/templvalueopt.sil
+++ b/test/SILOptimizer/templvalueopt.sil
@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -temp-lvalue-opt | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -temp-lvalue-elimination | %FileCheck %s
 
 import Swift
 import Builtin
@@ -84,14 +84,14 @@ struct AddressOnlyPayload {
 //
 // CHECK-LABEL: sil @test_initialize_struct :
 // CHECK:      bb0(%0 : $*TestStruct, %1 : $*Any, %2 : $Int):
-// HECK-NEXT:   [[E:%[0-9]+]] = struct_element_addr %0
-// HECK-NEXT:   [[LEFT:%[0-9]+]] = init_enum_data_addr [[E]]
-// HECK-NEXT:   [[A:%[0-9]+]] = struct_element_addr [[LEFT]]
-// HECK-NEXT:   copy_addr %1 to [init] [[A]]
-// HECK-NEXT:   [[I:%[0-9]+]] = struct_element_addr [[LEFT]]
-// HECK-NEXT:   store %2 to [[I]]
-// HECK-NEXT:   inject_enum_addr [[E]]
-// HECK-NOT:    copy_addr
+// CHECK-NEXT:   [[E:%[0-9]+]] = struct_element_addr %0
+// CHECK-NEXT:   [[LEFT:%[0-9]+]] = init_enum_data_addr [[E]]
+// CHECK-NEXT:   [[A:%[0-9]+]] = struct_element_addr [[LEFT]]
+// CHECK-NEXT:   copy_addr %1 to [init] [[A]]
+// CHECK-NEXT:   [[I:%[0-9]+]] = struct_element_addr [[LEFT]]
+// CHECK-NEXT:   store %2 to [[I]]
+// CHECK-NEXT:   inject_enum_addr [[E]]
+// CHECK-NOT:    copy_addr
 // CHECK: } // end sil function 'test_initialize_struct'
 sil @test_initialize_struct : $@convention(method) (@in Any, Int) -> @out TestStruct {
 bb0(%0 : $*TestStruct, %1 : $*Any, %2 : $Int):
@@ -165,14 +165,14 @@ struct StructWithEnum : Proto {
 
 // CHECK-LABEL: sil @move_projections :
 // CHECK:      bb0(%0 : $*any Proto, %1 : $*Any):
-// HECK-NEXT:   [[S:%[0-9]+]] = init_existential_addr %0 : $*any Proto, $StructWithEnum
-// HECK-NEXT:   [[E:%[0-9]+]] = struct_element_addr [[S]] : $*StructWithEnum, #StructWithEnum.e
-// HECK-NEXT:   [[ENUMA:%[0-9]+]] = init_enum_data_addr [[E]] : $*Enum, #Enum.A!enumelt
-// HECK-NEXT:   [[OPTIONAL:%[0-9]+]] = init_enum_data_addr [[ENUMA]] : $*Optional<Any>, #Optional.some!enumelt
-// HECK-NEXT:   copy_addr [take] %1 to [init] [[OPTIONAL]] : $*Any
-// HECK-NEXT:   inject_enum_addr [[ENUMA]] : $*Optional<Any>, #Optional.some!enumelt
-// HECK-NEXT:   inject_enum_addr [[E]] : $*Enum, #Enum.A!enumelt
-// HECK-NOT:    copy_addr
+// CHECK-NEXT:   [[S:%[0-9]+]] = init_existential_addr %0 : $*any Proto, $StructWithEnum
+// CHECK-NEXT:   [[E:%[0-9]+]] = struct_element_addr [[S]] : $*StructWithEnum, #StructWithEnum.e
+// CHECK-NEXT:   [[ENUMA:%[0-9]+]] = init_enum_data_addr [[E]] : $*Enum, #Enum.A!enumelt
+// CHECK-NEXT:   [[OPTIONAL:%[0-9]+]] = init_enum_data_addr [[ENUMA]] : $*Optional<Any>, #Optional.some!enumelt
+// CHECK-NEXT:   copy_addr [take] %1 to [init] [[OPTIONAL]] : $*Any
+// CHECK-NEXT:   inject_enum_addr [[ENUMA]] : $*Optional<Any>, #Optional.some!enumelt
+// CHECK-NEXT:   inject_enum_addr [[E]] : $*Enum, #Enum.A!enumelt
+// CHECK-NOT:    copy_addr
 // CHECK: } // end sil function 'move_projections'
 sil @move_projections : $@convention(thin) (@in Any) -> @out Proto {
 bb0(%0 : $*Proto, %1 : $*Any):
@@ -290,8 +290,9 @@ enum FakeOptional {
 sil @initfn : $@convention(thin) () -> @out Klass
 
 // CHECK-LABEL: sil @test_enum
-// CHECK: alloc_stack
-// CHECK: alloc_stack
+// CHECK:         [[I:%.*]] = init_enum_data_addr %0
+// CHECK:         [[S:%.*]] = alloc_stack $Klass
+// CHECK:         copy_addr [take] [[S]] to [init] [[I]]
 // CHECK-LABEL: } // end sil function 'test_enum'
 sil @test_enum : $@convention(thin) () -> @out FakeOptional {
 bb0(%0 : $*FakeOptional):
diff --git a/test/SILOptimizer/templvalueopt.swift b/test/SILOptimizer/templvalueopt.swift
index 6c3a7c86a4097..944b792f0473d 100644
--- a/test/SILOptimizer/templvalueopt.swift
+++ b/test/SILOptimizer/templvalueopt.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -module-name=test -O -enable-ossa-modules -Xllvm -sil-print-types -emit-sil  %s | %FileCheck %s
+// RUN: %target-swift-frontend -module-name=test -O -Xllvm -sil-print-types -emit-sil  %s | %FileCheck %s
 
 // RUN: %empty-directory(%t) 
 // RUN: %target-build-swift -O -module-name=test %s -o %t/a.out
diff --git a/test/SILOptimizer/templvalueopt_and_exclusivity.swift b/test/SILOptimizer/templvalueopt_and_exclusivity.swift
new file mode 100644
index 0000000000000..d3847a512f569
--- /dev/null
+++ b/test/SILOptimizer/templvalueopt_and_exclusivity.swift
@@ -0,0 +1,68 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-build-swift %t/module.swift -parse-as-library -O -enable-library-evolution -module-name=Module -emit-module -emit-module-path %t/Module.swiftmodule
+// RUN: %target-build-swift %t/module.swift -parse-as-library -O -enable-library-evolution -module-name=Module -c -o %t/module.o
+// RUN: %target-build-swift -parse-as-library -O %t/main.swift -I%t %t/module.o -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: executable_test
+
+
+// Check that TempLValueElimination does not cause an exclusivity violation at runtime.
+
+//--- module.swift
+
+public struct ResilientStruct {
+  public init() {}
+}
+
+//--- main.swift
+
+import Module
+
+struct MyState {
+  var _prop: String
+  var prop: String
+  {
+    @storageRestrictions(initializes: _prop)
+    init(initialValue) {
+      _prop = initialValue
+    }
+    get {
+      return _prop
+    }
+  }
+
+  let resilient = ResilientStruct()
+
+  init(prop: String) {
+    self.prop = prop
+  }
+}
+
+class Node {
+  var state = MyState(prop: "initial value")
+
+  func update(_ body: (inout MyState) -> Void) {
+    body(&state)
+  }
+}
+
+@inline(never)
+func test_exclusivity() {
+  let node = Node()
+  node.update { state in
+    state = MyState(prop: "new value")
+  }
+}
+
+@main
+enum App {
+  static func main() {
+    test_exclusivity()
+    // CHECK: success
+    print("success")
+  }
+}
diff --git a/test/SILOptimizer/templvalueopt_ossa.sil b/test/SILOptimizer/templvalueopt_ossa.sil
index e245ef8cd876f..17474d3aeb877 100644
--- a/test/SILOptimizer/templvalueopt_ossa.sil
+++ b/test/SILOptimizer/templvalueopt_ossa.sil
@@ -1,9 +1,10 @@
-// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -temp-lvalue-opt | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -temp-lvalue-elimination | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 
 import Swift
 import Builtin
+import SwiftShims
 
 // CHECK-LABEL: sil [ossa] @test_enum_with_initialize :
 // CHECK:      bb0(%0 : $*Optional<Any>, %1 : $*Any):
@@ -84,14 +85,14 @@ struct AddressOnlyPayload {
 //
 // CHECK-LABEL: sil [ossa] @test_initialize_struct :
 // CHECK:      bb0(%0 : $*TestStruct, %1 : $*Any, %2 : $Int):
-// HECK-NEXT:   [[E:%[0-9]+]] = struct_element_addr %0
-// HECK-NEXT:   [[LEFT:%[0-9]+]] = init_enum_data_addr [[E]]
-// HECK-NEXT:   [[A:%[0-9]+]] = struct_element_addr [[LEFT]]
-// HECK-NEXT:   copy_addr [take] %1 to [init] [[A]]
-// HECK-NEXT:   [[I:%[0-9]+]] = struct_element_addr [[LEFT]]
-// HECK-NEXT:   store %2 to [trivial] [[I]]
-// HECK-NEXT:   inject_enum_addr [[E]]
-// HECK-NOT:    copy_addr
+// CHECK-NEXT:   [[E:%[0-9]+]] = struct_element_addr %0
+// CHECK-NEXT:   [[LEFT:%[0-9]+]] = init_enum_data_addr [[E]]
+// CHECK-NEXT:   [[A:%[0-9]+]] = struct_element_addr [[LEFT]]
+// CHECK-NEXT:   copy_addr [take] %1 to [init] [[A]]
+// CHECK-NEXT:   [[I:%[0-9]+]] = struct_element_addr [[LEFT]]
+// CHECK-NEXT:   store %2 to [trivial] [[I]]
+// CHECK-NEXT:   inject_enum_addr [[E]]
+// CHECK-NOT:    copy_addr
 // CHECK: } // end sil function 'test_initialize_struct'
 sil [ossa] @test_initialize_struct : $@convention(method) (@in Any, Int) -> @out TestStruct {
 bb0(%0 : $*TestStruct, %1 : $*Any, %2 : $Int):
@@ -165,14 +166,14 @@ struct StructWithEnum : Proto {
 
 // CHECK-LABEL: sil [ossa] @move_projections :
 // CHECK:      bb0(%0 : $*any Proto, %1 : $*Any):
-// HECK-NEXT:   [[S:%[0-9]+]] = init_existential_addr %0 : $*any Proto, $StructWithEnum
-// HECK-NEXT:   [[E:%[0-9]+]] = struct_element_addr [[S]] : $*StructWithEnum, #StructWithEnum.e
-// HECK-NEXT:   [[ENUMA:%[0-9]+]] = init_enum_data_addr [[E]] : $*Enum, #Enum.A!enumelt
-// HECK-NEXT:   [[OPTIONAL:%[0-9]+]] = init_enum_data_addr [[ENUMA]] : $*Optional<Any>, #Optional.some!enumelt
-// HECK-NEXT:   copy_addr [take] %1 to [init] [[OPTIONAL]] : $*Any
-// HECK-NEXT:   inject_enum_addr [[ENUMA]] : $*Optional<Any>, #Optional.some!enumelt
-// HECK-NEXT:   inject_enum_addr [[E]] : $*Enum, #Enum.A!enumelt
-// HECK-NOT:    copy_addr
+// CHECK-NEXT:   [[S:%[0-9]+]] = init_existential_addr %0 : $*any Proto, $StructWithEnum
+// CHECK-NEXT:   [[E:%[0-9]+]] = struct_element_addr [[S]] : $*StructWithEnum, #StructWithEnum.e
+// CHECK-NEXT:   [[ENUMA:%[0-9]+]] = init_enum_data_addr [[E]] : $*Enum, #Enum.A!enumelt
+// CHECK-NEXT:   [[OPTIONAL:%[0-9]+]] = init_enum_data_addr [[ENUMA]] : $*Optional<Any>, #Optional.some!enumelt
+// CHECK-NEXT:   copy_addr [take] %1 to [init] [[OPTIONAL]] : $*Any
+// CHECK-NEXT:   inject_enum_addr [[ENUMA]] : $*Optional<Any>, #Optional.some!enumelt
+// CHECK-NEXT:   inject_enum_addr [[E]] : $*Enum, #Enum.A!enumelt
+// CHECK-NOT:    copy_addr
 // CHECK: } // end sil function 'move_projections'
 sil [ossa] @move_projections : $@convention(thin) (@in Any) -> @out Proto {
 bb0(%0 : $*Proto, %1 : $*Any):
@@ -335,6 +336,39 @@ bb0(%0 : @guaranteed $Any, %1 : $*Any):
   return %11 : $()
 }
 
+sil [readnone] @createAny_effects : $@convention(thin) () -> @out Any
+sil [readnone] @createAny_no_barrier_effects : $@convention(thin) () -> @out Any {
+ [global:]
+}
+
+// CHECK-LABEL: sil [ossa] @test_deinit_barrier_effects :
+// CHECK:         copy_addr [take]
+// CHECK-LABEL: } // end sil function 'test_deinit_barrier_effects'
+sil [ossa] @test_deinit_barrier_effects : $@convention(thin) (@guaranteed Any, @inout Any) -> () {
+bb0(%0 : @guaranteed $Any, %1 : $*Any):
+  %2 = alloc_stack $Any
+  %4 = function_ref @createAny_effects : $@convention(thin) () -> @out Any
+  %5 = apply %4(%2) : $@convention(thin) () -> @out Any
+  copy_addr [take] %2 to %1 : $*Any
+  dealloc_stack %2 : $*Any
+  %11 = tuple ()
+  return %11 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @test_no_deinit_barrier_effects :
+// CHECK-NOT:     copy_addr
+// CHECK-LABEL: } // end sil function 'test_no_deinit_barrier_effects'
+sil [ossa] @test_no_deinit_barrier_effects : $@convention(thin) (@guaranteed Any, @inout Any) -> () {
+bb0(%0 : @guaranteed $Any, %1 : $*Any):
+  %2 = alloc_stack $Any
+  %4 = function_ref @createAny_no_barrier_effects : $@convention(thin) () -> @out Any
+  %5 = apply %4(%2) : $@convention(thin) () -> @out Any
+  copy_addr [take] %2 to %1 : $*Any
+  dealloc_stack %2 : $*Any
+  %11 = tuple ()
+  return %11 : $()
+}
+
 struct TwoFields {
   var a: Child
   var b: Child
@@ -403,3 +437,268 @@ bb0(%0 : $*TwoFields, %1 : @owned $Child):
   return %8
 }
 
+// CHECK-LABEL: sil [ossa] @multi_block :
+// CHECK:       bb0({{.*}}):
+// CHECK-NEXT:    [[SA:%.*]] = struct_element_addr %0
+// CHECK-NEXT:    destroy_addr [[SA]]
+// CHECK-NEXT:    cond_br
+// CHECK:       bb1:
+// CHECK:         store {{.*}} to [init] [[SA]]
+// CHECK:       bb2:
+// CHECK:         store {{.*}} to [init] [[SA]]
+// CHECK:       bb3:
+// CHECK-NEXT:    tuple
+// CHECK-NEXT:    return
+// CHECK-LABEL: } // end sil function 'multi_block'
+sil [ossa] @multi_block : $@convention(thin) (@inout TwoFields, @guaranteed Child, @guaranteed Child) -> () {
+bb0(%0 : $*TwoFields, %1 : @guaranteed $Child, %2 : @guaranteed $Child):
+  %3 = alloc_stack $Child
+  cond_br undef, bb1, bb2
+
+bb1:
+  %5 = copy_value %1
+  store %5 to [init] %3
+  br bb3
+
+bb2:
+  %8 = copy_value %2
+  store %8 to [init] %3
+  br bb3
+
+bb3:
+  %11 = struct_element_addr %0, #TwoFields.a
+  copy_addr [take] %3 to %11
+  dealloc_stack %3
+  %14 = tuple ()
+  return %14
+}
+
+// CHECK-LABEL: sil [ossa] @multi_block_with_mutation :
+// CHECK:       bb0({{.*}}):
+// CHECK-NEXT:    alloc_stack
+// CHECK-LABEL: } // end sil function 'multi_block_with_mutation'
+sil [ossa] @multi_block_with_mutation : $@convention(thin) (@inout TwoFields, @guaranteed Child, @guaranteed Child) -> () {
+bb0(%0 : $*TwoFields, %1 : @guaranteed $Child, %2 : @guaranteed $Child):
+  %3 = alloc_stack $Child
+  %4 = struct_element_addr %0, #TwoFields.a
+  cond_br undef, bb1, bb2
+
+bb1:
+  %5 = copy_value %1
+  store %5 to [init] %3
+  br bb3
+
+bb2:
+  %8 = copy_value %2
+  store %8 to [init] %3
+  %10 = copy_value %2
+  store %10 to [assign] %4
+  br bb3
+
+bb3:
+  copy_addr [take] %3 to %4
+  dealloc_stack %3
+  %14 = tuple ()
+  return %14
+}
+
+// CHECK-LABEL: sil [ossa] @multi_block_with_multiple_deallocs :
+// CHECK:       bb0({{.*}}):
+// CHECK-NEXT:    alloc_stack
+// CHECK-LABEL: } // end sil function 'multi_block_with_multiple_deallocs'
+sil [ossa] @multi_block_with_multiple_deallocs : $@convention(thin) (@inout TwoFields, @guaranteed Child, @guaranteed Child) -> () {
+bb0(%0 : $*TwoFields, %1 : @guaranteed $Child, %2 : @guaranteed $Child):
+  %3 = alloc_stack $Child
+  %4 = struct_element_addr %0, #TwoFields.a
+  %5 = struct_element_addr %0, #TwoFields.b
+  cond_br undef, bb1, bb2
+
+bb1:
+  %6 = copy_value %1
+  store %6 to [init] %3
+  copy_addr [take] %3 to %4
+  dealloc_stack %3
+  br bb3
+
+bb2:
+  %8 = copy_value %2
+  store %8 to [init] %3
+  copy_addr [take] %3 to %5
+  dealloc_stack %3
+  br bb3
+
+bb3:
+  %14 = tuple ()
+  return %14
+}
+
+// CHECK-LABEL: sil [ossa] @copy_addr_not_in_dealloc_block :
+// CHECK:       bb0({{.*}}):
+// CHECK-NEXT:    alloc_stack
+// CHECK-LABEL: } // end sil function 'copy_addr_not_in_dealloc_block'
+sil [ossa] @copy_addr_not_in_dealloc_block : $@convention(thin) (@inout TwoFields, @guaranteed Child, @guaranteed Child) -> () {
+bb0(%0 : $*TwoFields, %1 : @guaranteed $Child, %2 : @guaranteed $Child):
+  %3 = alloc_stack $Child
+  %4 = struct_element_addr %0, #TwoFields.a
+  %5 = struct_element_addr %0, #TwoFields.b
+  cond_br undef, bb1, bb2
+
+bb1:
+  %6 = copy_value %1
+  store %6 to [init] %3
+  copy_addr [take] %3 to %4
+  br bb3
+
+bb2:
+  %8 = copy_value %2
+  store %8 to [init] %3
+  copy_addr [take] %3 to %5
+  br bb3
+
+bb3:
+  dealloc_stack %3
+  %14 = tuple ()
+  return %14
+}
+
+// CHECK-LABEL: sil [ossa] @empty :
+// CHECK:       bb0({{.*}}):
+// CHECK-NEXT:    alloc_stack
+// CHECK-LABEL: } // end sil function 'empty'
+sil [ossa] @empty : $@convention(thin) () -> @out () {
+bb0(%0 : $*()):
+  %1 = alloc_stack $()
+  copy_addr [take] %1 to %0
+  dealloc_stack %1
+  %4 = tuple ()
+  return %4
+}
+
+// CHECK-LABEL: sil [ossa] @load_store :
+// CHECK:       bb0({{.*}}):
+// CHECK-NEXT:    [[A:%.*]] = struct_element_addr %0 : $*TwoFields, #TwoFields.a
+// CHECK-NEXT:    destroy_addr [[A]]
+// CHECK-NEXT:    store %1 to [init] [[A]]
+// CHECK-NEXT:    tuple
+// CHECK-NEXT:    return
+// CHECK-LABEL: } // end sil function 'load_store'
+sil [ossa] @load_store : $@convention(thin) (@inout TwoFields, @owned Child) -> () {
+bb0(%0 : $*TwoFields, %1 : @owned $Child):
+  %2 = alloc_stack $Child
+  store %1 to [init] %2
+  %4 = load [take] %2
+  dealloc_stack %2
+  %6 = struct_element_addr %0, #TwoFields.a
+  store %4 to [assign] %6
+  %8 = tuple ()
+  return %8
+}
+
+// CHECK-LABEL: sil [ossa] @load_store_with_mutation :
+// CHECK:         alloc_stack
+// CHECK-LABEL: } // end sil function 'load_store_with_mutation'
+sil [ossa] @load_store_with_mutation : $@convention(thin) (@inout TwoFields, @owned Child, @owned TwoFields) -> () {
+bb0(%0 : $*TwoFields, %1 : @owned $Child, %2 : @owned $TwoFields):
+  %3 = alloc_stack $Child
+  store %1 to [init] %3
+  %4 = load [take] %3
+  dealloc_stack %3
+  %6 = struct_element_addr %0, #TwoFields.a
+  store %2 to [assign] %0
+  store %4 to [assign] %6
+  %8 = tuple ()
+  return %8
+}
+
+// CHECK-LABEL: sil [ossa] @load_store_trivial :
+// CHECK:       bb0({{.*}}):
+// CHECK-NEXT:    store %1 to [trivial] %0
+// CHECK-NEXT:    tuple
+// CHECK-NEXT:    return
+// CHECK-LABEL: } // end sil function 'load_store_trivial'
+sil [ossa] @load_store_trivial : $@convention(thin) (@inout Int, Int) -> () {
+bb0(%0 : $*Int, %1 : $Int):
+  %2 = alloc_stack $Int
+  store %1 to [trivial] %2
+  %4 = load [trivial] %2
+  dealloc_stack %2
+  store %4 to [trivial] %0
+  %8 = tuple ()
+  return %8
+}
+
+// CHECK-LABEL: sil [ossa] @copy_addr_trivial :
+// CHECK:       bb0({{.*}}):
+// CHECK-NEXT:    store %1 to [trivial] %0
+// CHECK-NEXT:    tuple
+// CHECK-NEXT:    return
+// CHECK-LABEL: } // end sil function 'copy_addr_trivial'
+sil [ossa] @copy_addr_trivial : $@convention(thin) (@inout Int, Int) -> () {
+bb0(%0 : $*Int, %1 : $Int):
+  %2 = alloc_stack $Int
+  store %1 to [trivial] %2
+  copy_addr %2 to %0
+  dealloc_stack %2
+  %8 = tuple ()
+  return %8
+}
+
+// CHECK-LABEL: sil [ossa] @projections_outside_liverange :
+// CHECK-NOT:     alloc_stack
+// CHECK-LABEL: } // end sil function 'projections_outside_liverange'
+sil [ossa] @projections_outside_liverange : $@convention(thin) (@guaranteed __ContiguousArrayStorageBase) -> () {
+bb0(%0 : @guaranteed $__ContiguousArrayStorageBase):
+  %1 = alloc_stack $Int
+  %2 = ref_element_addr %0, #__ContiguousArrayStorageBase.countAndCapacity
+  %3 = struct_element_addr %2, #_ArrayBody._storage
+  %4 = struct_element_addr %3, #_SwiftArrayBodyStorage.count
+  %5 = struct_element_addr %4, #Int._value
+  %6 = load [trivial] %5
+  %7 = struct $Int (%6)
+  store %7 to [trivial] %1
+  %9 = load [trivial] %1
+  store %9 to [trivial] %4
+  dealloc_stack %1
+  %12 = tuple ()
+  return %12
+}
+
+// CHECK-LABEL: sil [ossa] @destroy_before_copy :
+// CHECK:       bb1:
+// CHECK-NEXT:    destroy_addr
+// CHECK-LABEL: } // end sil function 'destroy_before_copy'
+sil [ossa] @destroy_before_copy : $@convention(thin) (@in_guaranteed Child) -> @out Child {
+bb0(%0 : $*Child, %1 : $*Child):
+  %2 = alloc_stack $Child
+  copy_addr %1 to [init] %2
+  br bb1
+
+bb1:
+  destroy_addr %2
+  copy_addr %1 to [init] %2
+  copy_addr %2 to [init] %0
+  br bb2
+
+bb2:
+  copy_addr [take] %2 to %0
+  dealloc_stack %2
+  %r = tuple ()
+  return %r
+}
+
+// CHECK-LABEL: sil [ossa] @dont_propagate_with_access_scope :
+// CHECK:         alloc_stack
+// CHECK:         copy_addr
+// CHECK-LABEL: } // end sil function 'dont_propagate_with_access_scope'
+sil [ossa] @dont_propagate_with_access_scope : $@convention(thin) (@inout Int, Int) -> () {
+bb0(%0 : $*Int, %1 : $Int):
+  %2 = alloc_stack $Int
+  %3 = begin_access [modify] [dynamic] %2
+  store %1 to [trivial] %3
+  end_access %3
+  copy_addr %2 to %0
+  dealloc_stack %2
+  %8 = tuple ()
+  return %8
+}
+
diff --git a/test/SILOptimizer/testflag_disable_pass_only.swift b/test/SILOptimizer/testflag_disable_pass_only.swift
index dc295cb11728f..14fb1b4e97673 100644
--- a/test/SILOptimizer/testflag_disable_pass_only.swift
+++ b/test/SILOptimizer/testflag_disable_pass_only.swift
@@ -1,25 +1,25 @@
-// RUN: %target-swift-frontend -emit-sil %s -Xllvm -sil-disable-pass=AllocBoxToStack -Xllvm -sil-disable-pass-only-function='$s26testflag_disable_pass_only4foo1yyF' | %FileCheck %s
+// RUN: %target-swift-frontend -emit-sil %s -Xllvm -sil-disable-pass=DiagnosticConstantPropagation,OnoneSimplification -Xllvm -sil-disable-pass-only-function='$s26testflag_disable_pass_only4foo1SiyF' | %FileCheck %s
 
-// CHECK-LABEL: sil hidden [noinline] @$s26testflag_disable_pass_only4foo1yyF :
-// CHECK: alloc_box 
-// CHECK-LABEL: } // end sil function '$s26testflag_disable_pass_only4foo1yyF'
+// CHECK-LABEL: sil hidden [noinline] @$s26testflag_disable_pass_only4foo1SiyF :
+// CHECK:         cond_br
+// CHECK-LABEL: } // end sil function '$s26testflag_disable_pass_only4foo1SiyF'
 @inline(never)
-func foo1() {
-  var a = 100
-  @inline(never)
-  func bar() {
-    print(a)
+func foo1() -> Int {
+  let a = 100
+  if a < 10 {
+    return 0
   }
+  return 10
 }
 
-// CHECK-LABEL: sil hidden [noinline] @$s26testflag_disable_pass_only4foo2yyF :
-// CHECK-NOT: alloc_box 
-// CHECK-LABEL: } // end sil function '$s26testflag_disable_pass_only4foo2yyF'
+// CHECK-LABEL: sil hidden [noinline] @$s26testflag_disable_pass_only4foo2SiyF :
+// CHECK-NOT:     bb1
+// CHECK-LABEL: } // end sil function '$s26testflag_disable_pass_only4foo2SiyF'
 @inline(never)
-func foo2() {
-  var a = 100
-  @inline(never)
-  func bar() {
-    print(a)
+func foo2() -> Int {
+  let a = 100
+  if a < 10 {
+    return 0
   }
+  return 10
 }
diff --git a/test/SILOptimizer/throws_prediction.swift b/test/SILOptimizer/throws_prediction.swift
index f7f2664b2de3d..01d36e127c67f 100644
--- a/test/SILOptimizer/throws_prediction.swift
+++ b/test/SILOptimizer/throws_prediction.swift
@@ -16,7 +16,7 @@
 // RUN:   -sil-verify-all -module-name=test -emit-sil \
 // RUN:       | %FileCheck --check-prefix CHECK-DISABLED %s
 
-// UNSUPPORTED: CPU=armv7k || CPU=arm64_32
+// UNSUPPORTED: CPU=armv7k, CPU=arm64_32, CPU=armv7
 
 // CHECK-DISABLED-NOT: normal_count
 
diff --git a/test/SILOptimizer/unavailable_enum_element_mandatory_custom_domain.swift b/test/SILOptimizer/unavailable_enum_element_mandatory_custom_domain.swift
new file mode 100644
index 0000000000000..30c4bd5b5d26d
--- /dev/null
+++ b/test/SILOptimizer/unavailable_enum_element_mandatory_custom_domain.swift
@@ -0,0 +1,63 @@
+// RUN: %target-swift-emit-sil -module-name Test %s -verify -parse-as-library \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -define-enabled-availability-domain EnabledDomain \
+// RUN:   -define-always-enabled-availability-domain AlwaysEnabledDomain \
+// RUN:   -define-disabled-availability-domain DisabledDomain \
+// RUN:   -define-dynamic-availability-domain DynamicDomain \
+// RUN:   -Onone \
+// RUN:   | %FileCheck %s --check-prefixes=CHECK,CHECK-NOOPT
+
+// REQUIRES: swift_feature_CustomAvailability
+
+public enum Enum {
+  case alwaysAvailable
+
+  @available(*, unavailable)
+  case alwaysUnavailable
+
+  @available(EnabledDomain)
+  case enabled
+
+  @available(EnabledDomain, unavailable)
+  case enabledUnavailable
+
+  @available(AlwaysEnabledDomain)
+  case alwaysEnabled
+
+  @available(AlwaysEnabledDomain, unavailable)
+  case alwaysEnabledUnavailable
+
+  @available(DisabledDomain)
+  case disabled
+
+  @available(DisabledDomain, unavailable)
+  case disabledUnavailable
+
+  @available(DynamicDomain)
+  case dynamic
+
+  @available(DynamicDomain, unavailable)
+  case dynamicUnavailable
+}
+
+// CHECK-LABEL: sil @$s4Test22testFullyCoveredSwitchyyAA4EnumOF : $@convention(thin) (Enum) -> () {
+// CHECK:         switch_enum %0, case #Enum.alwaysAvailable!enumelt: {{bb[0-9]+}}, case #Enum.alwaysUnavailable!enumelt: {{bb[0-9]+}}, case #Enum.enabled!enumelt: {{bb[0-9]+}}, case #Enum.alwaysEnabled!enumelt: {{bb[0-9]+}}, case #Enum.disabledUnavailable!enumelt: {{bb[0-9]+}}, case #Enum.dynamic!enumelt: {{bb[0-9]+}}, case #Enum.dynamicUnavailable!enumelt: {{bb[0-9]+}}, default [[DEFAULTBB:bb[0-9]+]]
+// CHECK:       [[DEFAULTBB]]:
+// CHECK-NEXT:    integer_literal $Builtin.Int1, -1
+// CHECK-NEXT:    cond_fail {{%.*}}, "unexpected enum value"
+// CHECK-NEXT:    unreachable
+// CHECK:       } // end sil function '$s4Test22testFullyCoveredSwitchyyAA4EnumOF'
+public func testFullyCoveredSwitch(_ e: Enum) {
+  switch e {
+  case .alwaysAvailable: ()
+  case .alwaysUnavailable: ()
+  case .enabled: ()
+  case .enabledUnavailable: ()
+  case .alwaysEnabled: ()
+  case .alwaysEnabledUnavailable: ()
+  case .disabled: ()
+  case .disabledUnavailable: ()
+  case .dynamic: ()
+  case .dynamicUnavailable: ()
+  }
+}
diff --git a/test/SILOptimizer/unsafeAddress.swift b/test/SILOptimizer/unsafeAddress.swift
index 2d0dac1e47e45..393abc4fabaa1 100644
--- a/test/SILOptimizer/unsafeAddress.swift
+++ b/test/SILOptimizer/unsafeAddress.swift
@@ -15,6 +15,8 @@ struct NC: ~Copyable {
 }
 
 struct S {
+  var s: String
+
   var data: NC {
     unsafeAddress { return makeUpAPointer() }
   }
@@ -72,7 +74,7 @@ func testCMod(c: C) {
   mod(&c.mutableData)
 }
 
-// CHECK-LABEL: sil hidden @$s4main11testSBorrow1syAA1SV_tF : $@convention(thin) (S) -> () {
+// CHECK-LABEL: sil hidden @$s4main11testSBorrow1syAA1SV_tF : $@convention(thin) (@guaranteed S) -> () {
 // CHECK: [[ADR:%.*]] = pointer_to_address %{{.*}} to [strict] $*NC
 // CHECK: [[MD:%.*]] = mark_dependence [nonescaping] [[ADR]] on %0
 // CHECK: begin_access [read] [unsafe] [[MD]]
@@ -114,7 +116,7 @@ func testSInoutBorrow(mut_s s: inout S) {
 // CHECK: [[ACCESS:%.*]] = begin_access [read] [static] %0
 // CHECK: [[LD:%.*]] = load [[ACCESS]]
 // CHECK: [[ADR:%.*]] = pointer_to_address %{{.*}} to [strict] $*NC
-// CHECK: [[MD:%.*]] = mark_dependence [nonescaping] [[ADR]] on [[LD]]
+// CHECK: [[MD:%.*]] = mark_dependence [nonescaping] [[ADR]] on [[ACCESS]]
 // CHECK: begin_access [read] [unsafe] [[MD]]
 // CHECK: apply
 // CHECK: end_access
diff --git a/test/SILOptimizer/unsafebufferpointer.swift b/test/SILOptimizer/unsafebufferpointer.swift
index 24b170c0a7236..85785f21324fc 100644
--- a/test/SILOptimizer/unsafebufferpointer.swift
+++ b/test/SILOptimizer/unsafebufferpointer.swift
@@ -5,6 +5,9 @@
 // This is an end-to-end test to ensure that the optimizer generates
 // optimal code for UnsafeBufferPointer.
 
+// TODO: for some reason code generation for armv7 is not optimal in some cases
+// REQUIRES: PTRSIZE=64
+
 // CHECK-LABEL: define {{.*}}testIteration
 
 // Check if the code contains no traps at all.
diff --git a/test/SILOptimizer/variadic_generics.sil b/test/SILOptimizer/variadic_generics.sil
index 4b37f59207be9..c4272e270edc4 100644
--- a/test/SILOptimizer/variadic_generics.sil
+++ b/test/SILOptimizer/variadic_generics.sil
@@ -3,7 +3,7 @@
 import Swift
 import Builtin
 
-sil [ossa] [always_inline] @scalar_pack_index : $<each T> () -> () {
+sil [ossa] [heuristic_always_inline] @scalar_pack_index : $<each T> () -> () {
 bb0:
   %0 = scalar_pack_index 0 of $Pack{Int, repeat each T}
   %1 = scalar_pack_index 1 of $Pack{repeat each T, Int}
@@ -33,7 +33,7 @@ bb0:
   return %ret : $()
 }
 
-sil [ossa] [always_inline] @pack_pack_index : $<each T> (Builtin.Word) -> () {
+sil [ossa] [heuristic_always_inline] @pack_pack_index : $<each T> (Builtin.Word) -> () {
 bb0(%i: $Builtin.Word):
   %index = dynamic_pack_index %i of $Pack{repeat each T}
   %0 = pack_pack_index 1, %index of $Pack{Int, repeat each T}
@@ -69,7 +69,7 @@ bb0(%i: $Builtin.Word):
   return %ret : $()
 }
 
-sil [ossa] [always_inline] @tuple_pack_element : $<each T> (Builtin.Word, @inout (repeat each T)) -> () {
+sil [ossa] [heuristic_always_inline] @tuple_pack_element : $<each T> (Builtin.Word, @inout (repeat each T)) -> () {
 bb0(%i: $Builtin.Word, %tuple : $*(repeat each T)):
   %index = dynamic_pack_index %i of $Pack{repeat each T}
   %tok = open_pack_element %index of <each Z> at <Pack{repeat each T}>, shape $Z, uuid "01234567-89AB-CDEF-0123-000000000000"
diff --git a/test/SPI/client_reuse_spi.swift b/test/SPI/client_reuse_spi.swift
index b23a64102f92d..e5c7048641f8a 100644
--- a/test/SPI/client_reuse_spi.swift
+++ b/test/SPI/client_reuse_spi.swift
@@ -4,7 +4,7 @@
 // RUN: split-file %s %t
 // RUN: %target-swift-frontend -emit-module %t/A.swift -module-name A -emit-module-path %t/A.swiftmodule
 // RUN: %target-swift-frontend -emit-module %t/B.swift -module-name B -emit-module-path %t/B.swiftmodule -I %t
-// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unknown %t/C.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -verify-ignore-unknown %t/C.swift -I %t
 
 //--- A.swift
 @_spi(A) public struct SecretStruct {
diff --git a/test/SPI/implementation_only_spi_import.swift b/test/SPI/implementation_only_spi_import.swift
index 58721566c5de4..a9865a0ad5974 100644
--- a/test/SPI/implementation_only_spi_import.swift
+++ b/test/SPI/implementation_only_spi_import.swift
@@ -4,7 +4,7 @@
 // RUN: %target-swift-frontend -emit-module -DLIB_A %s -module-name A -emit-module-path %t/A.swiftmodule
 // RUN: %target-swift-frontend -emit-module -DLIB_B %s -module-name B -emit-module-path %t/B.swiftmodule -I %t
 // RUN: rm %t/A.swiftmodule
-// RUN: %target-swift-frontend -typecheck -verify -DLIB_C %s -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -DLIB_C %s -I %t
 
 #if LIB_A
 
diff --git a/test/SPI/implementation_only_spi_import_exposability.swift b/test/SPI/implementation_only_spi_import_exposability.swift
index de3354d7303da..b62354a15e1af 100644
--- a/test/SPI/implementation_only_spi_import_exposability.swift
+++ b/test/SPI/implementation_only_spi_import_exposability.swift
@@ -3,7 +3,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -DLIB %s -module-name Lib -emit-module-path %t/Lib.swiftmodule \
 // RUN:   -swift-version 5 -enable-library-evolution
-// RUN: %target-typecheck-verify-swift -DCLIENT -I %t \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -DCLIENT -I %t \
 // RUN:   -swift-version 5 -enable-library-evolution
 
 #if LIB
diff --git a/test/SPI/implicit_spi_import.swift b/test/SPI/implicit_spi_import.swift
index 21a504313f3e5..93f77aa59cb26 100644
--- a/test/SPI/implicit_spi_import.swift
+++ b/test/SPI/implicit_spi_import.swift
@@ -8,14 +8,14 @@
 // RUN:   -emit-module-interface-path %t/Lib.swiftinterface \
 // RUN:   -emit-private-module-interface-path %t/Lib.private.swiftinterface
 
-// RUN: %target-swift-frontend -typecheck -verify %t/ClientA.swift -I %t
-// RUN: %target-swift-frontend -typecheck -verify %t/ClientB.swift -I %t
-// RUN: %target-swift-frontend -typecheck -verify %t/ClientC.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/ClientA.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/ClientB.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/ClientC.swift -I %t
 
 // RUN: rm %t/Lib.swiftmodule
-// RUN: %target-swift-frontend -typecheck -verify %t/ClientA.swift -I %t
-// RUN: %target-swift-frontend -typecheck -verify %t/ClientB.swift -I %t
-// RUN: %target-swift-frontend -typecheck -verify %t/ClientC.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/ClientA.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/ClientB.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/ClientC.swift -I %t
 
 // RUN: %target-swift-frontend -emit-module %t/ClientA.swift \
 // RUN:   -module-name ClientA -swift-version 5 -I %t \
@@ -95,7 +95,9 @@ import Lib
 public func useImplicit() -> _Klass { return _Klass() } // expected-error{{cannot use class '_Klass' here; it is an SPI imported from 'Lib'}}
 
 @_spi(core)
-public func useSPICore() -> CoreStruct { return CoreStruct() } // expected-error{{cannot find type 'CoreStruct' in scope}}
+public func useSPICore() -> CoreStruct { return CoreStruct() }
+// expected-error@-1 {{cannot find type 'CoreStruct' in scope}}
+// expected-error@-2 {{cannot find 'CoreStruct' in scope}}
 
 public func useMain() -> APIProtocol? { return nil }
 
diff --git a/test/SPI/private-import-access-spi.swift b/test/SPI/private-import-access-spi.swift
index 763822c3b2224..ad6d7d68e9243 100644
--- a/test/SPI/private-import-access-spi.swift
+++ b/test/SPI/private-import-access-spi.swift
@@ -11,10 +11,10 @@
 // RUN:   -enable-private-imports
 
 /// Typecheck a @_private client.
-// RUN: %target-swift-frontend -typecheck -verify -I %t %t/PrivateClient.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t %t/PrivateClient.swift
 
 /// Typecheck a regular client building against the same Lib with private imports enabled.
-// RUN: %target-swift-frontend -typecheck -verify -I %t %t/RegularClient.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t %t/RegularClient.swift
 
 //--- Lib_FileA.swift
 @_spi(S) public func spiFuncA() {}
diff --git a/test/SPI/public_client.swift b/test/SPI/public_client.swift
index 20bb56a12cbf9..7c59617e4c02e 100644
--- a/test/SPI/public_client.swift
+++ b/test/SPI/public_client.swift
@@ -6,11 +6,11 @@
 // RUN: %target-swift-frontend -emit-module %S/Inputs/spi_helper.swift -module-name SPIHelper -emit-module-path %t/SPIHelper.swiftmodule -emit-module-interface-path %t/SPIHelper.swiftinterface -emit-private-module-interface-path %t/SPIHelper.private.swiftinterface -enable-library-evolution -swift-version 5 -parse-as-library
 
 /// Reading from swiftmodule
-// RUN: %target-typecheck-verify-swift -I %t -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t -verify-ignore-unknown
 
 /// Reading from .private.swiftinterface
 // RUN: rm %t/SPIHelper.swiftmodule
-// RUN: %target-typecheck-verify-swift -I %t -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t -verify-ignore-unknown
 
 /// Reading from the public .swiftinterface should raise errors on missing
 /// declarations.
diff --git a/test/SPI/reexported-spi-groups.swift b/test/SPI/reexported-spi-groups.swift
index 8b14766ee2fe0..665a07502069a 100644
--- a/test/SPI/reexported-spi-groups.swift
+++ b/test/SPI/reexported-spi-groups.swift
@@ -53,30 +53,30 @@
 /// Test diagnostics of a multifile client
 // RUN: %target-swift-frontend -typecheck \
 // RUN:   %t/Client_FileA.swift %t/Client_FileB.swift\
-// RUN:   -swift-version 5 -I %t -verify
+// RUN:   -swift-version 5 -I %t -verify -verify-ignore-unrelated
 
 /// SPIs are now reexported by any `@_exported` from Swift modules, no matter
 /// if `export_as` is present or not.
 // RUN: %target-swift-frontend -typecheck \
 // RUN:   %t/NonExportedAsClient.swift \
-// RUN:   -swift-version 5 -I %t -verify
+// RUN:   -swift-version 5 -I %t -verify -verify-ignore-unrelated
 
 /// Test that SPIs don't leak when not reexported
 // RUN: %target-swift-frontend -typecheck \
 // RUN:   %t/NonExporterClient.swift \
-// RUN:   -swift-version 5 -I %t -verify
+// RUN:   -swift-version 5 -I %t -verify -verify-ignore-unrelated
 
 /// Test diagnostics against private swiftinterfaces
 // RUN: rm %t/Exported.swiftmodule %t/Exporter.swiftmodule
 // RUN: %target-swift-frontend -typecheck \
 // RUN:   %t/Client_FileA.swift %t/Client_FileB.swift\
-// RUN:   -swift-version 5 -I %t -verify
+// RUN:   -swift-version 5 -I %t -verify -verify-ignore-unrelated
 
 /// Test diagnostics against public swiftinterfaces
 // RUN: rm %t/Exported.private.swiftinterface %t/Exporter.private.swiftinterface
 // RUN: %target-swift-frontend -typecheck \
 // RUN:   %t/PublicClient.swift \
-// RUN:   -swift-version 5 -I %t -verify
+// RUN:   -swift-version 5 -I %t -verify -verify-ignore-unrelated
 
 //--- module.modulemap
 module Exported {
diff --git a/test/SPI/report-ioi-in-spi.swift b/test/SPI/report-ioi-in-spi.swift
index 9f562d9845e50..b858382b6d4cf 100644
--- a/test/SPI/report-ioi-in-spi.swift
+++ b/test/SPI/report-ioi-in-spi.swift
@@ -9,13 +9,13 @@
 /// Use of IOI types in SPI signatures is an error with -experimental-spi-only-imports
 // RUN: %target-swift-frontend -emit-module %t/ClientSPIOnlyMode.swift -I %t \
 // RUN:   -enable-library-evolution \
-// RUN:   -swift-version 5 -verify \
+// RUN:   -swift-version 5 -verify -verify-ignore-unrelated \
 // RUN:   -experimental-spi-only-imports
 
 /// Use of IOI types in SPI signatures is a warning without -experimental-spi-only-imports
 // RUN: %target-swift-frontend -emit-module %t/ClientDefaultMode.swift -I %t \
 // RUN:   -enable-library-evolution \
-// RUN:   -swift-version 5 -verify
+// RUN:   -swift-version 5 -verify -verify-ignore-unrelated
 
 //--- Lib.swift
 
diff --git a/test/SPI/spi-only-and-library-level.swift b/test/SPI/spi-only-and-library-level.swift
index be904e2d65c6e..e9f02c4e027d2 100644
--- a/test/SPI/spi-only-and-library-level.swift
+++ b/test/SPI/spi-only-and-library-level.swift
@@ -5,16 +5,16 @@
 // RUN:   -module-name Lib -emit-module-path %t/Lib.swiftmodule \
 // RUN:   -swift-version 5
 // RUN: %target-swift-frontend -emit-module %t/APILib.swift -I %t \
-// RUN:   -swift-version 5 -verify \
+// RUN:   -swift-version 5 -verify -verify-ignore-unrelated \
 // RUN:   -experimental-spi-only-imports \
 // RUN:   -library-level api \
 // RUN:   -require-explicit-availability=ignore
 // RUN: %target-swift-frontend -emit-module %t/SPILib.swift -I %t \
-// RUN:   -swift-version 5 -verify \
+// RUN:   -swift-version 5 -verify -verify-ignore-unrelated \
 // RUN:   -experimental-spi-only-imports \
 // RUN:   -library-level spi
 // RUN: %target-swift-frontend -emit-module %t/OtherLib.swift -I %t \
-// RUN:   -swift-version 5 -verify \
+// RUN:   -swift-version 5 -verify -verify-ignore-unrelated \
 // RUN:   -experimental-spi-only-imports
 
 //--- Lib.swift
diff --git a/test/SPI/spi-only-import-exportability.swift b/test/SPI/spi-only-import-exportability.swift
index d2ef28d3b4a57..27a285e781bb2 100644
--- a/test/SPI/spi-only-import-exportability.swift
+++ b/test/SPI/spi-only-import-exportability.swift
@@ -13,9 +13,9 @@
 // RUN:   -swift-version 5 -enable-library-evolution -I %t
 
 /// Test the client.
-// RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t -verify \
+// RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t -verify -verify-ignore-unrelated \
 // RUN:   -experimental-spi-only-imports
-// RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t -verify \
+// RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t -verify -verify-ignore-unrelated \
 // RUN:   -experimental-spi-only-imports \
 // RUN:   -enable-library-evolution
 
diff --git a/test/SPI/spi_and_spi_available.swift b/test/SPI/spi_and_spi_available.swift
new file mode 100644
index 0000000000000..72c05e70bdd80
--- /dev/null
+++ b/test/SPI/spi_and_spi_available.swift
@@ -0,0 +1,60 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-typecheck-verify-swift \
+// RUN:   -enable-library-evolution -swift-version 5 \
+// RUN:   -library-level=api -require-explicit-availability=ignore
+
+// REQUIRES: OS=macosx
+
+@_spi_available(macOS, introduced: 12.0) @available(iOS 12.0, *)
+public struct SPIAvailableType { // expected-note {{struct declared here}}
+    public init() {}
+}
+
+@_spi(S)
+public struct NormalSPIType {
+    public init() {}
+}
+
+// SPI available in SPI available should be accepted.
+
+@_spi_available(macOS, introduced: 12.0) @available(iOS 12.0, *)
+public struct OtherSPIAvailableType {
+    public func foo(s: SPIAvailableType) {}
+}
+
+extension OtherSPIAvailableType {
+    public func bar(s: SPIAvailableType) {} // expected-error {{cannot use struct 'SPIAvailableType' here; it is SPI}} // FIXME We should allow this.
+}
+
+// Normal SPI in normal SPI should be accepted.
+
+@_spi(S)
+public struct OtherNormalSPIType {
+    public func foo(s: SPIAvailableType) {}
+}
+
+extension OtherNormalSPIType {
+    public func bar2(s: SPIAvailableType) {}
+}
+
+// Normal SPI in SPI available should be rejected.
+
+@_spi_available(macOS, introduced: 12.0) @available(iOS 12.0, *)
+public func SPIAvailableToSPI(s: NormalSPIType) {} // FIXME This should be an error
+
+@inlinable
+@_spi_available(macOS, introduced: 12.0) @available(iOS 12.0, *)
+public func inlinableSPIAvailable() {
+ let _: NormalSPIType = NormalSPIType() // FIXME There should be many errors here
+}
+
+// SPI available in normal SPI is currently accepted.
+
+@_spi(S)
+public func SPIToSPIAvailable(s: NormalSPIType) {}
+
+@inlinable
+@_spi(S)
+public func inlinableSPI() {
+ let _: SPIAvailableType = SPIAvailableType()
+}
diff --git a/test/SPI/spi_client.swift b/test/SPI/spi_client.swift
index f8f47c6187b79..574ff2569251f 100644
--- a/test/SPI/spi_client.swift
+++ b/test/SPI/spi_client.swift
@@ -6,11 +6,11 @@
 // RUN: %target-swift-frontend -emit-module %S/Inputs/spi_helper.swift -module-name SPIHelper -emit-module-path %t/SPIHelper.swiftmodule -emit-module-interface-path %t/SPIHelper.swiftinterface -emit-private-module-interface-path %t/SPIHelper.private.swiftinterface -enable-library-evolution -swift-version 5 -parse-as-library
 
 /// Reading from swiftmodule
-// RUN: %target-typecheck-verify-swift -I %t -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t -verify-ignore-unknown
 
 /// Reading from .private.swiftinterface
 // RUN: rm %t/SPIHelper.swiftmodule
-// RUN: %target-typecheck-verify-swift -I %t -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t -verify-ignore-unknown
 
 //// Reading from .swiftinterface should fail as it won't find the decls
 // RUN: rm %t/SPIHelper.private.swiftinterface
diff --git a/test/Sanitizers/asan/asan.swift b/test/Sanitizers/asan/asan.swift
index b6e38598a4636..d5636c0c5140c 100644
--- a/test/Sanitizers/asan/asan.swift
+++ b/test/Sanitizers/asan/asan.swift
@@ -1,5 +1,10 @@
 // XFAIL: OS=windows-msvc
 
+// This test hangs on aarch64 FreeBSD
+// XFAIL will try to run the test and the verify that the test fails, which
+// still hits the hang.
+// UNSUPPORTED: OS=freebsd && CPU=aarch64
+
 // RUN: %target-swiftc_driver %s -g -sanitize=address -o %t_asan-binary
 // RUN: %target-codesign %t_asan-binary
 // RUN: env %env-ASAN_OPTIONS=abort_on_error=0 not %target-run %t_asan-binary 2>&1 | %FileCheck %s
diff --git a/test/Sanitizers/tsan/async_taskgroup_next.swift b/test/Sanitizers/tsan/async_taskgroup_next.swift
index 5d1999f7b2814..bd776f742b887 100644
--- a/test/Sanitizers/tsan/async_taskgroup_next.swift
+++ b/test/Sanitizers/tsan/async_taskgroup_next.swift
@@ -6,6 +6,15 @@
 // REQUIRES: tsan_runtime
 // UNSUPPORTED: use_os_stdlib
 
+// Bug in TSan on FreeBSD
+// Thread destruction interceptor marks the thread ignored and then checks that
+// the thread isn't being ignored.
+// rdar://158450231
+// TSan is also occasionally detecting race conditions in the concurrency
+// runtime on FreeBSD.
+// rdar://158355890
+// XFAIL: OS=freebsd
+
 var scratchBuffer: UnsafeMutableBufferPointer<Int> = .allocate(capacity: 1000)
 
 @available(SwiftStdlib 5.1, *)
diff --git a/test/Sanitizers/tsan/basic_future.swift b/test/Sanitizers/tsan/basic_future.swift
index d14dbdd89bb3e..26b30d8dad73b 100644
--- a/test/Sanitizers/tsan/basic_future.swift
+++ b/test/Sanitizers/tsan/basic_future.swift
@@ -6,6 +6,12 @@
 // REQUIRES: tsan_runtime
 // UNSUPPORTED: use_os_stdlib
 
+// Bug in TSan on FreeBSD
+// Thread destruction interceptor marks the thread ignored and then checks that
+// the thread isn't being ignored.
+// rdar://158450231
+// XFAIL: OS=freebsd
+
 import Dispatch
 
 #if canImport(Darwin)
diff --git a/test/Sanitizers/tsan/mainactor.swift b/test/Sanitizers/tsan/mainactor.swift
index 3688a94f4c6d3..403467d2ed71f 100644
--- a/test/Sanitizers/tsan/mainactor.swift
+++ b/test/Sanitizers/tsan/mainactor.swift
@@ -7,6 +7,12 @@
 // UNSUPPORTED: use_os_stdlib
 // UNSUPPORTED: threading_none
 
+// Bug in TSan on FreeBSD
+// Thread destruction interceptor marks the thread ignored and then checks that
+// the thread isn't being ignored.
+// rdar://158450231
+// XFAIL: OS=freebsd
+
 import Dispatch
 
 /// @returns true iff the expected answer is actually the case, i.e., correct.
diff --git a/test/Sanitizers/tsan/norace-task-group-cancellation.swift b/test/Sanitizers/tsan/norace-task-group-cancellation.swift
index d467465d75996..7aecc6a751d25 100644
--- a/test/Sanitizers/tsan/norace-task-group-cancellation.swift
+++ b/test/Sanitizers/tsan/norace-task-group-cancellation.swift
@@ -7,6 +7,12 @@
 // UNSUPPORTED: back_deployment_runtime
 // UNSUPPORTED: use_os_stdlib
 
+// Bug in TSan on FreeBSD
+// Thread destruction interceptor marks the thread ignored and then checks that
+// the thread isn't being ignored.
+// rdar://158450231
+// XFAIL: OS=freebsd
+
 @main
 public struct TSANDataRaceOnCancel {
   public static func main() async throws {
diff --git a/test/Sanitizers/tsan/once.swift b/test/Sanitizers/tsan/once.swift
index c8816f1eedd79..514e3212ed12b 100644
--- a/test/Sanitizers/tsan/once.swift
+++ b/test/Sanitizers/tsan/once.swift
@@ -17,6 +17,12 @@
 // on some platforms TSan wasn't seeing the synchronization, so would report
 // a false positive.
 
+// TSan is detecting race conditions in the concurrency runtime.
+// This might be an issue in how it is hooked into the underlying threading
+// model on FreeBSD.
+// rdar://158355890
+// XFAIL: OS=freebsd
+
 import Dispatch
 
 var count = 0
diff --git a/test/Sanitizers/tsan/tsan.swift b/test/Sanitizers/tsan/tsan.swift
index 45894a33970af..8b2e242222b43 100644
--- a/test/Sanitizers/tsan/tsan.swift
+++ b/test/Sanitizers/tsan/tsan.swift
@@ -14,6 +14,12 @@
 // don't support TSan.
 // UNSUPPORTED: remote_run
 
+// TSan is detecting race conditions in the concurrency runtime.
+// This might be an issue in how it is hooked into the underlying threading
+// model on FreeBSD.
+// rdar://158355890
+// XFAIL: OS=freebsd
+
 #if canImport(Darwin)
   import Darwin
 #elseif canImport(Glibc)
@@ -50,7 +56,7 @@ var racey_x: Int;
 
 // TSan %deflake as part of the test.
 for _ in 1...5 {
-#if os(macOS) || os(iOS)
+#if os(macOS) || os(iOS) || os(FreeBSD)
   var t : pthread_t?
 #else
   var t : pthread_t = 0
@@ -61,7 +67,7 @@ for _ in 1...5 {
 
     return nil
   }, nil)
-#if os(macOS) || os(iOS)
+#if os(macOS) || os(iOS) || os(FreeBSD)
   threads.append(t!)
 #else
   threads.append(t)
diff --git a/test/ScanDependencies/Incremental/system_search_path_invalidate.swift b/test/ScanDependencies/Incremental/system_search_path_invalidate.swift
new file mode 100644
index 0000000000000..7e003ac018087
--- /dev/null
+++ b/test/ScanDependencies/Incremental/system_search_path_invalidate.swift
@@ -0,0 +1,17 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/Frameworks)
+
+// RUN: %target-swift-frontend -scan-dependencies -scanner-module-validation -module-load-mode prefer-interface -Rdependency-scan-cache -load-dependency-scan-cache -serialize-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache -module-cache-path %t/module-cache %s -o %t/deps.json -I %t/ExtraCModules -I %S/../Inputs/CHeaders -F %t/Frameworks &> %t/first_scan_output.txt
+// RUN: cat %t/first_scan_output.txt | %FileCheck %s
+
+// RUN: %target-swift-frontend -scan-dependencies -scanner-module-validation -module-load-mode prefer-interface -Rdependency-scan-cache -load-dependency-scan-cache -serialize-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache -module-cache-path %t/module-cache %s -o %t/deps.json -I %t/ExtraCModules -I %S/../Inputs/CHeaders -F %t/Frameworks &> %t/second_scan_output.txt
+// RUN: cat %t/second_scan_output.txt | %FileCheck %s -check-prefix=INCREMENTAL-CHECK
+
+// Change an '-F' to a '-Fsystem' and ensure that the serialized cache does not get reused
+// RUN: %target-swift-frontend -scan-dependencies -scanner-module-validation -module-load-mode prefer-interface -Rdependency-scan-cache -load-dependency-scan-cache -serialize-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache -module-cache-path %t/module-cache %s -o %t/deps.json -I %t/ExtraCModules -I %S/../Inputs/CHeaders -Fsystem %t/Frameworks &> %t/second_system_scan_output.txt
+// RUN: cat %t/second_system_scan_output.txt | %FileCheck %s
+
+// CHECK: remark: Incremental module scan: Failed to load module scanning dependency cache from:
+// INCREMENTAL-CHECK-NOT: remark: Incremental module scan: Failed to load module scanning dependency cache from:
+
diff --git a/test/ScanDependencies/Inputs/ModuleDependencyGraph.swift b/test/ScanDependencies/Inputs/ModuleDependencyGraph.swift
index 6037a5d954092..0fedfdb7b4475 100644
--- a/test/ScanDependencies/Inputs/ModuleDependencyGraph.swift
+++ b/test/ScanDependencies/Inputs/ModuleDependencyGraph.swift
@@ -13,14 +13,12 @@ import Foundation
 
 enum ModuleDependencyId: Hashable {
   case swift(String)
-  case swiftPlaceholder(String)
   case swiftPrebuiltExternal(String)
   case clang(String)
 
   var moduleName: String {
     switch self {
     case .swift(let name): return name
-    case .swiftPlaceholder(let name): return name
     case .swiftPrebuiltExternal(let name): return name
     case .clang(let name): return name
     }
@@ -30,7 +28,6 @@ enum ModuleDependencyId: Hashable {
 extension ModuleDependencyId: Codable {
   enum CodingKeys: CodingKey {
     case swift
-    case swiftPlaceholder
     case swiftPrebuiltExternal
     case clang
   }
@@ -42,16 +39,11 @@ extension ModuleDependencyId: Codable {
       self = .swift(moduleName)
     } catch {
       do {
-        let moduleName =  try container.decode(String.self, forKey: .swiftPlaceholder)
-        self = .swiftPlaceholder(moduleName)
+        let moduleName =  try container.decode(String.self, forKey: .swiftPrebuiltExternal)
+        self = .swiftPrebuiltExternal(moduleName)
       } catch {
-        do {
-          let moduleName =  try container.decode(String.self, forKey: .swiftPrebuiltExternal)
-          self = .swiftPrebuiltExternal(moduleName)
-        } catch {
-          let moduleName =  try container.decode(String.self, forKey: .clang)
-          self = .clang(moduleName)
-        }
+        let moduleName =  try container.decode(String.self, forKey: .clang)
+        self = .clang(moduleName)
       }
     }
   }
@@ -61,8 +53,6 @@ extension ModuleDependencyId: Codable {
     switch self {
       case .swift(let moduleName):
         try container.encode(moduleName, forKey: .swift)
-      case .swiftPlaceholder(let moduleName):
-        try container.encode(moduleName, forKey: .swiftPlaceholder)
       case .swiftPrebuiltExternal(let moduleName):
         try container.encode(moduleName, forKey: .swiftPrebuiltExternal)
       case .clang(let moduleName):
@@ -99,15 +89,6 @@ struct SwiftModuleDetails: Codable {
   var swiftOverlayDependencies: [ModuleDependencyId]?
 }
 
-/// Details specific to Swift placeholder dependencies.
-struct SwiftPlaceholderModuleDetails: Codable {
-  /// The path to the .swiftModuleDoc file.
-  var moduleDocPath: String?
-
-  /// The path to the .swiftSourceInfo file.
-  var moduleSourceInfoPath: String?
-}
-
 /// Details specific to Swift externally-pre-built modules.
 struct SwiftPrebuiltExternalModuleDetails: Codable {
   /// The path to the already-compiled module that must be used instead of
@@ -152,10 +133,6 @@ struct ModuleInfo: Codable {
     /// a bridging header.
     case swift(SwiftModuleDetails)
 
-    /// Swift placeholder modules carry additional details that specify their
-    /// module doc path and source info paths.
-    case swiftPlaceholder(SwiftPlaceholderModuleDetails)
-
     /// Swift externally-prebuilt modules must communicate the path to pre-built binary artifacts
     case swiftPrebuiltExternal(SwiftPrebuiltExternalModuleDetails)
 
@@ -167,7 +144,6 @@ struct ModuleInfo: Codable {
 extension ModuleInfo.Details: Codable {
   enum CodingKeys: CodingKey {
     case swift
-    case swiftPlaceholder
     case swiftPrebuiltExternal
     case clang
   }
@@ -179,18 +155,12 @@ extension ModuleInfo.Details: Codable {
       self = .swift(details)
     } catch {
       do {
-        let details = try container.decode(SwiftPlaceholderModuleDetails.self,
-                                           forKey: .swiftPlaceholder)
-        self = .swiftPlaceholder(details)
+        let details = try container.decode(SwiftPrebuiltExternalModuleDetails.self,
+                                           forKey: .swiftPrebuiltExternal)
+        self = .swiftPrebuiltExternal(details)
       } catch {
-        do {
-          let details = try container.decode(SwiftPrebuiltExternalModuleDetails.self,
-                                             forKey: .swiftPrebuiltExternal)
-          self = .swiftPrebuiltExternal(details)
-        } catch {
-          let details = try container.decode(ClangModuleDetails.self, forKey: .clang)
-          self = .clang(details)
-        }
+        let details = try container.decode(ClangModuleDetails.self, forKey: .clang)
+        self = .clang(details)
       }
     }
   }
@@ -200,8 +170,6 @@ extension ModuleInfo.Details: Codable {
     switch self {
       case .swift(let details):
         try container.encode(details, forKey: .swift)
-      case .swiftPlaceholder(let details):
-        try container.encode(details, forKey: .swiftPlaceholder)
       case .swiftPrebuiltExternal(let details):
         try container.encode(details, forKey: .swiftPrebuiltExternal)
       case .clang(let details):
diff --git a/test/ScanDependencies/binary_framework_dependency.swift b/test/ScanDependencies/binary_framework_dependency.swift
index 23d888653372f..fc759da45342f 100644
--- a/test/ScanDependencies/binary_framework_dependency.swift
+++ b/test/ScanDependencies/binary_framework_dependency.swift
@@ -15,8 +15,15 @@
 
 import Foo
 
+// Appears as a dependency of the main module
 // CHECK: "swiftPrebuiltExternal": "Foo"
+
+// Appears as, specifically, a source-imported dependency of the main module
+// CHECK:      "swiftPrebuiltExternal": "Foo"
+
+// Actual node in the dependency graph for module 'Foo'
 // CHECK:      "swiftPrebuiltExternal": "Foo"
+
 // CHECK-NEXT:    },
 // CHECK-NEXT:    {
 // CHECK-NEXT:      "modulePath": 
diff --git a/test/ScanDependencies/bridging-header-autochaining.swift b/test/ScanDependencies/bridging-header-autochaining.swift
index 9a1169ef5f7fb..57839b7493cba 100644
--- a/test/ScanDependencies/bridging-header-autochaining.swift
+++ b/test/ScanDependencies/bridging-header-autochaining.swift
@@ -2,8 +2,8 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
-// RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
-// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O -module-load-mode prefer-serialized \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -scanner-module-validation \
 // RUN:   %t/test.swift -o %t/deps.json -auto-bridging-header-chaining -scanner-output-dir %t -scanner-debug-write-output \
 // RUN:   -Xcc -fmodule-map-file=%t/a.modulemap -Xcc -fmodule-map-file=%t/b.modulemap -import-objc-header %t/Bridging.h
 
@@ -17,8 +17,6 @@
 
 // RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
 // RUN: %swift_frontend_plain @%t/shim.cmd
-// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json Swift > %t/swift.cmd
-// RUN: %swift_frontend_plain @%t/swift.cmd
 // RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:B > %t/B.cmd
 // RUN: %swift_frontend_plain @%t/B.cmd
 // RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:A > %t/A.cmd
@@ -27,7 +25,7 @@
 // RUN: %{python} %S/../CAS/Inputs/GenerateExplicitModuleMap.py %t/deps.json > %t/map.json
 
 // RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json bridgingHeader > %t/header.cmd
-// RUN: %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules -O -o %t/bridging.pch
+// RUN: %target-swift-frontend @%t/header.cmd %t/Bridging.h -disable-implicit-swift-modules -O -o %t/bridging.pch
 
 // RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json Test > %t/MyApp.cmd
 // RUN: echo "\"-disable-implicit-string-processing-module-import\"" >> %t/MyApp.cmd
@@ -51,8 +49,8 @@
 // RUN:   -I %t %t/user2.swift -import-objc-header %t/Bridging2.h
 
 /// Importing binary module with bridging header from a module that has no bridging header.
-// RUN: %target-swift-frontend -scan-dependencies -module-name User -module-cache-path %t/clang-module-cache -O \
-// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN: %target-swift-frontend -scan-dependencies -module-name User -module-cache-path %t/clang-module-cache -O -module-load-mode prefer-serialized \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -scanner-module-validation \
 // RUN:   %t/user.swift -o %t/deps2.json -auto-bridging-header-chaining -scanner-output-dir %t -scanner-debug-write-output \
 // RUN:   -Xcc -fmodule-map-file=%t/a.modulemap -Xcc -fmodule-map-file=%t/b.modulemap -I %t -enable-library-evolution
 
@@ -83,8 +81,8 @@
 // NO-OBJC-LEAKING-NOT: import __ObjC
 
 /// Importing binary module with bridging header from a module with bridging header using explicit build method with header chaining.
-// RUN: %target-swift-frontend -scan-dependencies -module-name User -O \
-// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN: %target-swift-frontend -scan-dependencies -module-name User -O -module-load-mode prefer-serialized \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -scanner-module-validation \
 // RUN:   -Xcc -fmodule-map-file=%t/a.modulemap -Xcc -fmodule-map-file=%t/b.modulemap \
 // RUN:   -I %t %t/user2.swift -import-objc-header %t/Bridging2.h -auto-bridging-header-chaining -scanner-output-dir %t -scanner-debug-write-output \
 // RUN:   -o %t/deps3.json
@@ -96,14 +94,21 @@
 // RUN:   -Xcc -fmodule-map-file=%t/a.modulemap -Xcc -fmodule-map-file=%t/b.modulemap -I %t > %t/header2.h
 // RUN:   %FileCheck %s --check-prefix=HEADER2 --input-file=%t/header2.h
 // HEADER2: #include
-// HEADER2-SAME: Bridging2.h
-// HEADER2: #include
 // HEADER2-SAME: Bridging.h
+// HEADER2: #include
+// HEADER2-SAME: Bridging2.h
+
+// RUN: %FileCheck %s --check-prefix DEPS_JSON --input-file=%t/deps3.json
+// DEPS_JSON: "chainedBridgingHeaderPath":
+// DEPS_JSON-SAME: -ChainedBridgingHeader.h
+// DEPS_JSON: "bridgingHeader":
+// DEPS_JSON-NEXT: "path":
+// DEPS_JSON-SAME: Bridging2.h
+// DEPS_JSON-NEXT: "sourceFiles":
+// DEPS_JSON-NEXT: Bridging2.h
 
 // RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps3.json clang:SwiftShims > %t/shim2.cmd
 // RUN: %swift_frontend_plain @%t/shim2.cmd
-// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps3.json Swift > %t/swift2.cmd
-// RUN: %swift_frontend_plain @%t/swift2.cmd
 // RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps3.json clang:B > %t/B2.cmd
 // RUN: %swift_frontend_plain @%t/B2.cmd
 // RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps3.json clang:A > %t/A2.cmd
@@ -131,15 +136,24 @@
 // OBJC-HEADER-SAME: Bridging2.h
 // OBJC-HEADER-NOT: ChainedBridgingHeader.h
 
-// RUN: %target-swift-frontend -scan-dependencies -module-name User -O \
-// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN: %target-swift-frontend -scan-dependencies -module-name User -O -module-load-mode prefer-serialized \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -scanner-module-validation \
 // RUN:   -Xcc -fmodule-map-file=%t/a.modulemap -Xcc -fmodule-map-file=%t/b.modulemap \
 // RUN:   -I %t %t/user2.swift -import-objc-header %t/Bridging3.h -auto-bridging-header-chaining -scanner-output-dir %t -scanner-debug-write-output \
 // RUN:   -o %t/deps4.json -Rdependency-scan-cache -serialize-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache
 
+// RUN: %FileCheck %s --check-prefix DEPS_JSON2 --input-file=%t/deps4.json
+// DEPS_JSON2: "chainedBridgingHeaderPath":
+// DEPS_JSON2-SAME: -ChainedBridgingHeader.h
+// DEPS_JSON2: "bridgingHeader":
+// DEPS_JSON2-NEXT: "path":
+// DEPS_JSON2-SAME: Bridging3.h
+// DEPS_JSON2-NEXT: "sourceFiles":
+// DEPS_JSON2-NEXT: Bridging3.h
+
 /// Make sure the cache is correct.
-// RUN: %target-swift-frontend -scan-dependencies -module-name User -O \
-// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN: %target-swift-frontend -scan-dependencies -module-name User -O -module-load-mode prefer-serialized \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -scanner-module-validation \
 // RUN:   -Xcc -fmodule-map-file=%t/a.modulemap -Xcc -fmodule-map-file=%t/b.modulemap \
 // RUN:   -I %t %t/user2.swift -import-objc-header %t/Bridging3.h -auto-bridging-header-chaining -scanner-output-dir %t -scanner-debug-write-output \
 // RUN:   -o %t/deps4.json -Rdependency-scan-cache -load-dependency-scan-cache -serialize-dependency-scan-cache \
@@ -188,6 +202,8 @@ extension A {
     public func testA() {}
 }
 
+public class AB : B {}
+
 //--- user2.swift
 import Test
 
diff --git a/test/ScanDependencies/bridging_header_error.swift b/test/ScanDependencies/bridging_header_error.swift
new file mode 100644
index 0000000000000..8a948e239a60c
--- /dev/null
+++ b/test/ScanDependencies/bridging_header_error.swift
@@ -0,0 +1,7 @@
+// REQUIRES: objc_interop
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/module-cache %s -o %t/deps.json -import-objc-header %t/does-this-header-even-exist.h &> %t/diagnostic_output.txt
+// RUN: cat %t/diagnostic_output.txt | %FileCheck %s
+// CHECK: error: bridging header dependency scanning failure: error: no such file or directory: '{{.*}}does-this-header-even-exist.h'
diff --git a/test/ScanDependencies/cached-missing-module-found-in-serialized-paths.swift b/test/ScanDependencies/cached-missing-module-found-in-serialized-paths.swift
new file mode 100644
index 0000000000000..c078691e1ecd2
--- /dev/null
+++ b/test/ScanDependencies/cached-missing-module-found-in-serialized-paths.swift
@@ -0,0 +1,44 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/deps)
+// RUN: %empty-directory(%t/moreDeps)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/deps/B.swiftmodule -module-cache-path %t/module-cache %t/B.swift -module-name B -I %t/moreDeps
+
+// Put the dependency module into a location discoverable by the first scan which will succeed and serialize scanner state
+// RUN: cp %t/moreDeps/C.swiftinterface %t/deps/C.swiftinterface
+
+// RUN: %target-swift-frontend -scan-dependencies -o %t/deps.json %t/client.swift -I %t/deps -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -Rdependency-scan-cache -serialize-dependency-scan-cache -load-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache &> %t/initial_output.txt
+
+// Remove the 'C' dependency module into a location not discoverable by the second scan in order to trigger a failure and use serialized scanner state
+// to emit the diagnostic
+// RUN: rm %t/deps/C.swiftinterface
+
+// RUN: %target-swift-frontend -scan-dependencies -o %t/deps.json %t/client.swift -I %t/deps -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -Rdependency-scan-cache -load-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache -validate-prior-dependency-scan-cache &> %t/output.txt
+// RUN: cat %t/output.txt | %FileCheck %s
+
+// CHECK: remark: Incremental module scan: Re-using serialized module scanning dependency cache from: '{{.*}}cache.moddepcache'.
+// CHECK: remark: Incremental module scan: Dependency info for module 'C' invalidated due to a modified input since last scan: '{{.*}}deps{{/|\\}}C.swiftinterface'.
+// CHECK: remark: Incremental module scan: Dependency info for module 'deps' invalidated due to an out-of-date dependency.
+// CHECK: error: compilation search paths unable to resolve module dependency: 'C'
+// CHECK: note: 'C' can be found using a search path that was specified when building module 'B' ('{{.*}}moreDeps'). This search path was not explicitly specified on the current compilation
+// CHECK: note: a dependency of main module 'deps'
+
+//--- moreDeps/C.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name C -enable-library-evolution
+public struct structC {}
+
+//--- deps/A.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name A -enable-library-evolution
+public func funcA() {}
+
+//--- B.swift
+public func funcB() {}
+
+//--- client.swift
+import A
+import B
+import C
diff --git a/test/ScanDependencies/can_import_placeholder.swift b/test/ScanDependencies/can_import_placeholder.swift
deleted file mode 100644
index 9a42e2b9a04a2..0000000000000
--- a/test/ScanDependencies/can_import_placeholder.swift
+++ /dev/null
@@ -1,42 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: mkdir -p %t/clang-module-cache
-// RUN: mkdir -p %t/inputs
-
-// RUN: echo "[{" > %/t/inputs/map.json
-// RUN: echo "\"moduleName\": \"SomeExternalModule\"," >> %/t/inputs/map.json
-// RUN: echo "\"modulePath\": \"%/t/inputs/SomeExternalModule.swiftmodule\"," >> %/t/inputs/map.json
-// RUN: echo "\"docPath\": \"%/t/inputs/SomeExternalModule.swiftdoc\"," >> %/t/inputs/map.json
-// RUN: echo "\"sourceInfoPath\": \"%/t/inputs/SomeExternalModule.swiftsourceinfo\"," >> %/t/inputs/map.json
-// RUN: echo "\"isFramework\": false" >> %/t/inputs/map.json
-// RUN: echo "}]" >> %/t/inputs/map.json
-
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -module-cache-path %t/clang-module-cache %s -placeholder-dependency-module-map-file %t/inputs/map.json -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/Inputs/CHeaders/Bridging.h -swift-version 4
-// RUN: %validate-json %t/deps.json | %FileCheck %s
-
-// Ensure that round-trip serialization does not affect result
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -test-dependency-scan-cache-serialization -module-cache-path %t/clang-module-cache %s -placeholder-dependency-module-map-file %t/inputs/map.json -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/Inputs/CHeaders/Bridging.h -swift-version 4
-// RUN: %validate-json %t/deps.json | %FileCheck %s
-
-// REQUIRES: executable_test
-// REQUIRES: objc_interop
-#if canImport(SomeExternalModule)
-import SomeExternalModule
-#endif
-
-// CHECK: "mainModuleName": "deps"
-
-/// --------Main module
-// CHECK-LABEL: "modulePath": "deps.swiftmodule",
-// CHECK-NEXT: sourceFiles
-// CHECK-NEXT: can_import_placeholder.swift
-
-// CHECK: directDependencies
-// CHECK-NEXT: {
-// CHECK-DAG: "swift": "F"
-// CHECK-DAG: "swiftPlaceholder": "SomeExternalModule"
-// CHECK-DAG: "swift": "Swift"
-// CHECK-DAG: "swift": "SwiftOnoneSupport"
-// CHECK-DAG: "swift": "_Concurrency"
-// CHECK-DAG: "swift": "_StringProcessing"
-// CHECK-DAG: "clang": "_SwiftConcurrencyShims"
-// CHECK: ],
diff --git a/test/ScanDependencies/candidate_binary_module_diagnostics.swift b/test/ScanDependencies/candidate_binary_module_diagnostics.swift
new file mode 100644
index 0000000000000..59c5a6fdf1026
--- /dev/null
+++ b/test/ScanDependencies/candidate_binary_module_diagnostics.swift
@@ -0,0 +1,22 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/moduleInputs)
+// RUN: %empty-directory(%t/moduleInputs2)
+// RUN: split-file %s %t
+
+// RUN: echo "Not Really a module" >> %t/moduleInputs/FooBar.swiftmodule
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %t/main.swift -o %t/deps.json -I %t/moduleInputs -diagnostic-style llvm -scanner-module-validation 2>&1 | %FileCheck %s -check-prefix=ERROR
+
+// ERROR: error: unable to resolve Swift module dependency to a compatible module: 'FooBar'
+// ERROR: note: found incompatible module '{{.*}}{{/|\\}}moduleInputs{{/|\\}}FooBar.swiftmodule': malformed
+
+// RUN: %target-swift-frontend -emit-module %t/FooBar.swift -emit-module-path %t/moduleInputs2/FooBar.swiftmodule -module-name FooBar
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %t/main.swift -o %t/deps.json -I %t/moduleInputs -I %t/moduleInputs2 -diagnostic-style llvm -scanner-module-validation 2>&1 | %FileCheck %s -check-prefix=WARNING
+
+// WARNING: warning: module file '{{.*}}{{/|\\}}moduleInputs{{/|\\}}FooBar.swiftmodule' is incompatible with this Swift compiler: malformed
+
+//--- main.swift
+import FooBar
+
+//--- FooBar.swift
+public func fooBar() {}
diff --git a/test/ScanDependencies/clang_scan_error.swift b/test/ScanDependencies/clang_scan_error.swift
index 515ca91064176..f26f4150e5b9b 100644
--- a/test/ScanDependencies/clang_scan_error.swift
+++ b/test/ScanDependencies/clang_scan_error.swift
@@ -6,7 +6,7 @@
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
 // RUN:   -o %t/deps.json -I %t -swift-version 5 2>&1 | %FileCheck %s
 
-// CHECK: error: Clang dependency scanner failure: failed to scan bridging header dependencies
+// CHECK: error: bridging header dependency scanning failure: {{.*}}bridging.h:1:10: fatal error: 'do-not-exist.h' file not found
 
 //--- bridging.h
 #include "do-not-exist.h"
diff --git a/test/ScanDependencies/cxx-overlay-source-lookup.swift b/test/ScanDependencies/cxx-overlay-source-lookup.swift
new file mode 100644
index 0000000000000..bcc978d3931e3
--- /dev/null
+++ b/test/ScanDependencies/cxx-overlay-source-lookup.swift
@@ -0,0 +1,41 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/deps)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -o %t/deps.json %t/client.swift -I %t/deps -cxx-interoperability-mode=default -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import
+// RUN: cat %t/deps.json | %FileCheck %s
+
+/// --------Main module
+// CHECK-LABEL: "modulePath": "deps.swiftmodule",
+// CHECK-NEXT: "sourceFiles": [
+// CHECK-NEXT: cxx-overlay-source-lookup.swift
+// CHECK-NEXT: ],
+// CHECK: "directDependencies": [
+// CHECK-DAG: "swift": "Swift"
+// CHECK-DAG: "swift": "SwiftOnoneSupport"
+// CHECK-DAG: "swift": "Cxx"
+// CHECK-DAG: "swift": "CxxStdlib"
+// CHECK-DAG: "clang": "CxxShim"
+// CHECK-DAG: "clang": "Foo"
+// CHECK: ],
+
+//--- deps/bar.h
+void bar(void);
+
+//--- deps/foo.h
+#include "bar.h"
+void foo(void);
+
+//--- deps/module.modulemap
+module std_Bar [system] {
+  header "bar.h"
+  export *
+}
+
+module Foo {
+  header "foo.h"
+  export *
+}
+
+//--- client.swift
+import Foo
diff --git a/test/ScanDependencies/cxx-overlay-underlying-module-lookup.swift b/test/ScanDependencies/cxx-overlay-underlying-module-lookup.swift
new file mode 100644
index 0000000000000..d509ab559c355
--- /dev/null
+++ b/test/ScanDependencies/cxx-overlay-underlying-module-lookup.swift
@@ -0,0 +1,32 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend -scan-dependencies -o %t/deps.json %s -cxx-interoperability-mode=default -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import
+// RUN: %validate-json %t/deps.json | %FileCheck %s
+
+import CxxStdlib
+
+// CHECK: "mainModuleName": "deps"
+
+/// --------Main module
+// CHECK-LABEL: "modulePath": "deps.swiftmodule",
+// CHECK-NEXT: "sourceFiles": [
+// CHECK-NEXT: cxx-overlay-underlying-module-lookup.swift
+// CHECK-NEXT: ],
+
+// CHECK-NEXT: "directDependencies": [
+// CHECK-DAG:     "clang": "CxxShim"
+// CHECK-DAG:     "swift": "CxxStdlib"
+// CHECK-DAG:     "swift": "Cxx"
+// CHECK-DAG:     "swift": "Swift"
+// CHECK-DAG:     "swift": "SwiftOnoneSupport"
+// CHECK: ],
+
+/// ----------
+// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}CxxStdlib-{{.*}}.swiftmodule"
+// CHECK-NEXT: "sourceFiles": []
+// CHECK-NEXT: "directDependencies": [
+// CHECK-DAG:     "swift": "Cxx"
+// CHECK-DAG:     "swift": "Swift"
+// CHECK-DAG:     "clang": "std"
+// CHECK-DAG:     "clang": "CxxStdlibShim"
+// CHECK: ],
diff --git a/test/ScanDependencies/diagnose-missing-module-found-in-serialized-paths.swift b/test/ScanDependencies/diagnose-missing-module-found-in-serialized-paths.swift
new file mode 100644
index 0000000000000..f08ce6f5bb6c2
--- /dev/null
+++ b/test/ScanDependencies/diagnose-missing-module-found-in-serialized-paths.swift
@@ -0,0 +1,34 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/deps)
+// RUN: %empty-directory(%t/moreDeps)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/deps/B.swiftmodule -module-cache-path %t/module-cache %t/B.swift -module-name B -I %t/moreDeps
+
+// RUN: %target-swift-frontend -scan-dependencies -o %t/deps.json %t/client.swift -I %t/deps -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import &> %t/output.txt
+// RUN: cat %t/output.txt | %FileCheck %s
+
+// CHECK: error: compilation search paths unable to resolve module dependency: 'C'
+// CHECK: note: 'C' can be found using a search path that was specified when building module 'B' ('{{.*}}moreDeps'). This search path was not explicitly specified on the current compilation
+// CHECK: note: a dependency of Swift module 'B': '{{.*}}B.swiftmodule'
+// CHECK: note: a dependency of main module 'deps'
+
+//--- moreDeps/C.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name C -enable-library-evolution
+public struct structC {}
+
+//--- deps/A.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name A -enable-library-evolution
+public func funcA() {}
+
+//--- B.swift
+public import C
+public func funcB(_ input: structC) {}
+
+//--- client.swift
+import A
+import B
+
diff --git a/test/ScanDependencies/diagnose_dependency_cycle_overlay_source_target.swift b/test/ScanDependencies/diagnose_dependency_cycle_overlay_source_target.swift
new file mode 100644
index 0000000000000..e9120233ad302
--- /dev/null
+++ b/test/ScanDependencies/diagnose_dependency_cycle_overlay_source_target.swift
@@ -0,0 +1,52 @@
+// REQUIRES: objc_interop
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/inputs)
+// RUN: split-file %s %t
+// RUN: not %target-swift-frontend -scan-dependencies -module-cache-path %t/module-cache %t/test.swift -o %t/deps.json -I %t/inputs -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -module-name CycleKit  &> %t/out.txt
+// RUN: %FileCheck %s < %t/out.txt
+
+// CHECK: error: module dependency cycle: 'CycleKit (Source Target) -> A.swiftinterface -> CycleKit.swiftinterface'
+// CHECK: note: Swift Overlay dependency of 'A' on 'CycleKit' via Clang module dependency: 'A.swiftinterface -> A.pcm -> B.pcm -> CycleKit.pcm'
+
+//--- test.swift
+import A
+
+//--- inputs/CycleKit.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name CycleKit -enable-library-evolution
+
+public func CycleKitFunc() {}
+
+//--- inputs/A.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name A -enable-library-evolution
+@_exported import A
+public func AFunc() {}
+
+//--- inputs/A.h
+#import <B.h>
+void funcA(void);
+
+//--- inputs/B.h
+#import <CycleKit.h>
+void funcA(void);
+
+//--- inputs/CycleKit.h
+void funcCycleKit(void);
+
+//--- inputs/module.modulemap
+module A {
+  header "A.h"
+  export *
+}
+
+module B {
+  header "B.h"
+  export *
+}
+
+module CycleKit {
+  header "CycleKit.h"
+  export *
+}
diff --git a/test/ScanDependencies/diagnose_dependency_cycle_shadow.swift b/test/ScanDependencies/diagnose_dependency_cycle_shadow.swift
new file mode 100644
index 0000000000000..172a83ca741fd
--- /dev/null
+++ b/test/ScanDependencies/diagnose_dependency_cycle_shadow.swift
@@ -0,0 +1,80 @@
+// REQUIRES: objc_interop
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/inputs)
+
+// RUN: %empty-directory(%t/mock.sdk/System/Library/Frameworks/A.framework/Modules/A.swiftmodule)
+// RUN: %empty-directory(%t/mock.sdk/System/Library/Frameworks/A.framework/Headers)
+// RUN: %empty-directory(%t/mock.sdk/System/Library/Frameworks/CycleKit.framework/Modules/CycleKit.swiftmodule)
+// RUN: %empty-directory(%t/mock.sdk/System/Library/Frameworks/CycleKit.framework/Headers)
+
+// RUN: split-file %s %t
+
+// RUN: cp %t/inputs/A.swiftinterface %t/mock.sdk/System/Library/Frameworks/A.framework/Modules/A.swiftmodule/%target-swiftinterface-name
+// RUN: cp %t/inputs/framework_A.modulemap %t/mock.sdk/System/Library/Frameworks/A.framework/Modules/module.modulemap
+// RUN: cp %t/inputs/A-framework.h %t/mock.sdk/System/Library/Frameworks/A.framework/Headers/A.h
+
+// RUN: cp %t/inputs/CycleKit.swiftinterface %t/mock.sdk/System/Library/Frameworks/CycleKit.framework/Modules/CycleKit.swiftmodule/%target-swiftinterface-name
+// RUN: cp %t/inputs/framework_CycleKit.modulemap %t/mock.sdk/System/Library/Frameworks/CycleKit.framework/Modules/module.modulemap
+// RUN: cp %t/inputs/CycleKit.h %t/mock.sdk/System/Library/Frameworks/CycleKit.framework/Headers/CycleKit.h
+
+// Non-SDK dependency shadowing
+// RUN: not %target-swift-frontend -scan-dependencies -module-cache-path %t/module-cache %t/test.swift -o %t/deps.json -I %t/inputs -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -module-name CycleKit  &> %t/out.txt
+// RUN: %FileCheck --check-prefix=CHECK-NONSDK %s < %t/out.txt
+
+// CHECK-NONSDK: note: source target 'CycleKit' shadowing a Swift module with the same name at: '{{.*}}{{/|\\}}diagnose_dependency_cycle_shadow.swift.tmp{{/|\\}}inputs'
+
+// SDK dependency shadowing
+// RUN: not %target-swift-frontend -scan-dependencies -module-cache-path %t/module-cache %t/test.swift -o %t/deps.json -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -module-name CycleKit -sdk %t/mock.sdk &> %t/out-sdk.txt
+// RUN: %FileCheck --check-prefix=CHECK-SDK %s < %t/out-sdk.txt
+
+// CHECK-SDK: note: source target 'CycleKit' shadowing an SDK Swift module with the same name at: '{{.*}}{{/|\\}}mock.sdk{{/|\\}}System{{/|\\}}Library{{/|\\}}Frameworks{{/|\\}}CycleKit.framework{{/|\\}}Modules{{/|\\}}CycleKit.swiftmodule'
+
+//--- test.swift
+import A
+
+//--- inputs/CycleKit.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name CycleKit -enable-library-evolution
+
+public func CycleKitFunc() {}
+
+//--- inputs/A.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name A -enable-library-evolution
+@_exported import A
+public func AFunc() {}
+
+//--- inputs/A.h
+#import <CycleKit.h>
+void funcA(void);
+
+//--- inputs/A-framework.h
+#import <CycleKit/CycleKit.h>
+void funcA(void);
+
+//--- inputs/CycleKit.h
+void funcCycleKit(void);
+
+//--- inputs/module.modulemap
+module A {
+    header "A.h"
+    export *
+}
+
+module CycleKit {
+    header "CycleKit.h"
+    export *
+}
+
+//--- inputs/framework_A.modulemap
+framework module A {
+    header "A.h"
+    export *
+}
+
+//--- inputs/framework_CycleKit.modulemap
+framework module CycleKit {
+    header "CycleKit.h"
+    export *
+}
diff --git a/test/ScanDependencies/eliminate_unused_vfs.swift b/test/ScanDependencies/eliminate_unused_vfs.swift
index 854d6d290139e..d59fb245b28d5 100644
--- a/test/ScanDependencies/eliminate_unused_vfs.swift
+++ b/test/ScanDependencies/eliminate_unused_vfs.swift
@@ -75,7 +75,8 @@ import F
 /// Check that the dependency swift module hashes are identical when the vfs overlays are ignored.
 // MOD-HASH: "mainModuleName": "deps",
 // MOD-HASH: "linkLibraries": [],
-// MOD-HASH-NEXT: "details": {
+// MOD-HASH: "imports": [
+// MOD-HASH: "details": {
 // MOD-HASH-NEXT:   "swift": {
 // MOD-HASH-NEXT:   "moduleInterfacePath": "{{.*}}{{/|\\}}F.swiftinterface",
 // MOD-HASH:   "commandLine": [
@@ -86,6 +87,7 @@ import F
 // MOD-HASH:     ],
 // MOD-HASH: "mainModuleName": "deps1",
 // MOD-HASH: "linkLibraries": [],
+// MOD-HASH: "imports": [
 // MOD-HASH: "details": {
 // MOD-HASH-NEXT:   "swift": {
 // MOD-HASH-NEXT:   "moduleInterfacePath": "{{.*}}{{/|\\}}F.swiftinterface",
@@ -97,6 +99,7 @@ import F
 // MOD-HASH:     ],
 // MOD-HASH: "mainModuleName": "deps2",
 // MOD-HASH: "linkLibraries": [],
+// MOD-HASH: "imports": [
 // MOD-HASH: "details": {
 // MOD-HASH-NEXT:   "swift": {
 // MOD-HASH-NEXT:   "moduleInterfacePath": "{{.*}}{{/|\\}}F.swiftinterface",
diff --git a/test/ScanDependencies/embedded_no_textual.swift b/test/ScanDependencies/embedded_no_textual.swift
new file mode 100644
index 0000000000000..c221f2077ad4d
--- /dev/null
+++ b/test/ScanDependencies/embedded_no_textual.swift
@@ -0,0 +1,18 @@
+// REQUIRES: swift_feature_Embedded
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module %t/Foo.swift -emit-module-path %t/Foo.swiftmodule/%target-swiftmodule-name -module-name Foo -emit-module-interface-path %t/Foo.swiftmodule/%target-swiftinterface-name -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib -enable-library-evolution
+
+// RUN: %target-swift-frontend -scan-dependencies \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
+// RUN:   %t/main.swift -I %t -enable-experimental-feature Embedded -o - | %FileCheck %s --check-prefix=SERIALIZED
+
+// SERIALIZED: "swiftPrebuiltExternal": "Foo"
+
+//--- main.swift
+import Foo
+
+//--- Foo.swift
+public func foo() {}
+
diff --git a/test/ScanDependencies/enable-ossa-modules-pass-down.swift b/test/ScanDependencies/enable-ossa-modules-pass-down.swift
deleted file mode 100644
index 030d2d17d8484..0000000000000
--- a/test/ScanDependencies/enable-ossa-modules-pass-down.swift
+++ /dev/null
@@ -1,21 +0,0 @@
-// REQUIRES: objc_interop
-// RUN: %empty-directory(%t)
-// RUN: mkdir -p %t/clang-module-cache
-// RUN: mkdir -p %t/Frameworks
-// RUN: mkdir -p %t/Frameworks/E.framework/
-// RUN: mkdir -p %t/Frameworks/E.framework/Modules
-// RUN: mkdir -p %t/Frameworks/E.framework/Modules/E.swiftmodule
-
-// Copy over the interface
-// RUN: cp %S/Inputs/Swift/E.swiftinterface %t/Frameworks/E.framework/Modules/E.swiftmodule/%module-target-triple.swiftinterface
-
-// Run the scan
-// RUN: %target-swift-frontend -scan-dependencies -enable-ossa-modules -disable-implicit-swift-modules -module-load-mode prefer-interface %s -o %t/deps.json -F %t/Frameworks/ -sdk %t
-// RUN: %validate-json %t/deps.json | %FileCheck %s
-
-import E
-
-// CHECK: E.swiftmodule/{{.*}}.swiftinterface
-// CHECK: "commandLine": [
-// CHECK: "-enable-ossa-modules"
-// CHECK: ]
diff --git a/test/ScanDependencies/error_path.swift b/test/ScanDependencies/error_path.swift
index 0e128e2cea40b..6a659d5c6af56 100644
--- a/test/ScanDependencies/error_path.swift
+++ b/test/ScanDependencies/error_path.swift
@@ -5,11 +5,11 @@
 
 import P
 
-// CHECK:      {{.*}}{{/|\\}}Z.swiftinterface:3:8: error: Unable to find module dependency: 'missing_module'
+// CHECK:      {{.*}}{{/|\\}}Z.swiftinterface:3:8: error: unable to resolve module dependency: 'missing_module'
 // CHECK-NEXT: 1 | // swift-interface-format-version: 1.0
 // CHECK-NEXT: 2 | // swift-module-flags: -module-name Z
 // CHECK-NEXT: 3 | import missing_module
-// CHECK-NEXT:   |        |- error: Unable to find module dependency: 'missing_module'
+// CHECK-NEXT:   |        |- error: unable to resolve module dependency: 'missing_module'
 // CHECK-NEXT:   |        |- note: a dependency of Swift module 'Z': '{{.*}}{{/|\\}}Z.swiftinterface'
 // CHECK-NEXT:   |        |- note: a dependency of Swift module 'Y': '{{.*}}{{/|\\}}Y.swiftinterface'
 // CHECK-NEXT:   |        |- note: a dependency of Swift module 'P': '{{.*}}{{/|\\}}P.swiftinterface'
diff --git a/test/ScanDependencies/error_source_locations.swift b/test/ScanDependencies/error_source_locations.swift
index 599864ae4bb2c..2a57a2e51bba6 100644
--- a/test/ScanDependencies/error_source_locations.swift
+++ b/test/ScanDependencies/error_source_locations.swift
@@ -7,20 +7,20 @@ import P
 import FooBar
 
 
-// CHECK:      {{.*}}{{/|\\}}error_source_locations.swift:7:8: error: Unable to find module dependency: 'FooBar'
+// CHECK:      {{.*}}{{/|\\}}error_source_locations.swift:7:8: error: unable to resolve module dependency: 'FooBar'
 // CHECK-NEXT: 5 |
 // CHECK-NEXT: 6 | import P
 // CHECK-NEXT: 7 | import FooBar
-// CHECK-NEXT:   |        |- error: Unable to find module dependency: 'FooBar'
+// CHECK-NEXT:   |        |- error: unable to resolve module dependency: 'FooBar'
 // CHECK-NEXT:   |        `- note: a dependency of main module 'deps'
 // CHECK-NEXT: 8 |
 // CHECK-NEXT: 9 |
 
-// CHECK:      {{.*}}{{/|\\}}Z.swiftinterface:3:8: error: Unable to find module dependency: 'missing_module'
+// CHECK:      {{.*}}{{/|\\}}Z.swiftinterface:3:8: error: unable to resolve module dependency: 'missing_module'
 // CHECK-NEXT: 1 | // swift-interface-format-version: 1.0
 // CHECK-NEXT: 2 | // swift-module-flags: -module-name Z
 // CHECK-NEXT: 3 | import missing_module
-// CHECK-NEXT:   |        |- error: Unable to find module dependency: 'missing_module'
+// CHECK-NEXT:   |        |- error: unable to resolve module dependency: 'missing_module'
 // CHECK-NEXT:   |        |- note: a dependency of Swift module 'Z': '{{.*}}{{/|\\}}Z.swiftinterface'
 // CHECK-NEXT:   |        |- note: a dependency of Swift module 'Y': '{{.*}}{{/|\\}}Y.swiftinterface'
 // CHECK-NEXT:   |        |- note: a dependency of Swift module 'P': '{{.*}}{{/|\\}}P.swiftinterface'
diff --git a/test/ScanDependencies/explicit-scanner-input-can-import.swift b/test/ScanDependencies/explicit-scanner-input-can-import.swift
new file mode 100644
index 0000000000000..311611f83a0f4
--- /dev/null
+++ b/test/ScanDependencies/explicit-scanner-input-can-import.swift
@@ -0,0 +1,31 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/Inputs/Foo.swiftmodule)
+// RUN: split-file %s %t
+
+// Step 1: build swift interface and swift module side by side
+// RUN: %target-swift-frontend -emit-module %t/Foo.swift -emit-module-path %t/Inputs/Foo.swiftmodule/%target-swiftmodule-name -module-name Foo -user-module-version 22
+
+// Step 2: scan dependency should give us the binary module we specify with 'swift-module-file'
+// RUN: %target-swift-frontend -scan-dependencies %t/test.swift -o %t/deps.json -scanner-module-validation -swift-module-file=Foo=%t/Inputs/Foo.swiftmodule/%target-swiftmodule-name
+// RUN: %validate-json %t/deps.json | %FileCheck %s -check-prefix=CHECK-INPUT
+
+// Step 3: ensure that versioned canImport still applies with direct -swift-module-file
+// RUN: %target-swift-frontend -scan-dependencies %t/test_too_new.swift -o %t/deps.json -scanner-module-validation -swift-module-file=Foo=%t/Inputs/Foo.swiftmodule/%target-swiftmodule-name
+// RUN: %validate-json %t/deps.json | %FileCheck %s -check-prefix=CHECK-MISSING
+
+// CHECK-INPUT: "swiftPrebuiltExternal": "Foo"
+// CHECK-MISSING-NOT: "swiftPrebuiltExternal": "Foo"
+
+//--- Foo.swift
+public func foo() {}
+
+//--- test.swift
+#if canImport(Foo)
+import Foo
+#endif
+
+//--- test_too_new.swift
+#if canImport(Foo, _version: 23)
+import Foo
+#endif
diff --git a/test/ScanDependencies/explicit-scanner-input.swift b/test/ScanDependencies/explicit-scanner-input.swift
new file mode 100644
index 0000000000000..d7bbbc0e701f0
--- /dev/null
+++ b/test/ScanDependencies/explicit-scanner-input.swift
@@ -0,0 +1,33 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/Inputs/Foo.swiftmodule)
+// RUN: split-file %s %t
+
+// Step 1: build swift interface and swift module side by side
+// RUN: %target-swift-frontend -emit-module %t/Foo.swift -emit-module-path %t/Inputs/Foo.swiftmodule/%target-swiftmodule-name -module-name Foo
+
+// Step 2: scan dependency should give us the binary module we specify with 'swift-module-file'
+// RUN: %target-swift-frontend -scan-dependencies %t/test.swift -o %t/deps.json -scanner-module-validation -swift-module-file=Foo=%t/Inputs/Foo.swiftmodule/%target-swiftmodule-name
+// RUN: %validate-json %t/deps.json | %FileCheck %s -check-prefix=CHECK-INPUT
+
+// Step 3: ensure that if multiple inputs for the same module are specified then a warning is emitted and the latter is preferred
+// RUN: echo "Gibberish" > %t/Inputs/Foo.swiftmodule/NotAModule.swiftmodule
+// RUN: %target-swift-frontend -scan-dependencies %t/test.swift -o %t/deps.json -scanner-module-validation -swift-module-file=Foo=%t/Inputs/Foo.swiftmodule/NotAModule.swiftmodule -swift-module-file=Foo=%t/Inputs/Foo.swiftmodule/%target-swiftmodule-name -diagnostic-style llvm 2>&1 | %FileCheck %s -check-prefix=CHECK-WARN-MULTIPLE
+// RUN: %validate-json %t/deps.json | %FileCheck %s -check-prefix=CHECK-INPUT
+
+// Step 4: verify that the usual invalid module candidate diagnostics apply
+// RUN: echo "Not Really a module" > %t/Inputs/Foo.swiftmodule/%target-swiftmodule-name
+// RUN: %target-swift-frontend -scan-dependencies %t/test.swift -o %t/deps.json  -scanner-module-validation -swift-module-file=Foo=%t/Inputs/Foo.swiftmodule/%target-swiftmodule-name -diagnostic-style llvm 2>&1 | %FileCheck %s -check-prefix=CHECK-INVALID-MODULE-DIAG
+
+// CHECK-INPUT: "swiftPrebuiltExternal": "Foo"
+// CHECK-WARN-MULTIPLE: warning: multiple Swift module file inputs with identifier "Foo": replacing '{{.*}}NotAModule.swiftmodule'
+// CHECK-INVALID-MODULE-DIAG: error: unable to resolve Swift module dependency to a compatible module: 'Foo'
+// CHECK-INVALID-MODULE-DIAG: note: found incompatible module '{{.*}}': malformed
+
+//--- Foo.swift
+public func foo() {}
+
+//--- test.swift
+#if canImport(Foo)
+import Foo
+#endif
diff --git a/test/ScanDependencies/import_infos.swift b/test/ScanDependencies/import_infos.swift
new file mode 100644
index 0000000000000..021fd84783943
--- /dev/null
+++ b/test/ScanDependencies/import_infos.swift
@@ -0,0 +1,72 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/module-cache %s -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import
+// RUN: %validate-json %t/deps.json | %FileCheck %s
+
+// CHECK: "mainModuleName": "deps"
+// CHECK: "swift": "deps"
+// CHECK: "modulePath": "deps.swiftmodule"
+
+// CHECK: "imports": [
+// CHECK-NEXT:        {
+// CHECK-NEXT:          "identifier": "Swift"
+// CHECK-NEXT:          "accessLevel": "public"
+// CHECK-NEXT:        }
+// CHECK-NEXT:        {
+// CHECK-NEXT:          "identifier": "SwiftOnoneSupport"
+// CHECK-NEXT:          "accessLevel": "public"
+// CHECK-NEXT:        }
+// CHECK-NEXT:        {
+// CHECK-NEXT:          "identifier": "C"
+// CHECK-NEXT:          "accessLevel": "internal"
+// CHECK-NEXT:          "importLocations": [
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "bufferIdentifier": "{{.*}}import_infos.swift"
+// CHECK-NEXT:              "linuNumber": 65
+// CHECK-NEXT:              "columnNumber": 17
+// CHECK-NEXT:            }
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "bufferIdentifier": "{{.*}}import_infos.swift"
+// CHECK-NEXT:              "linuNumber": 72
+// CHECK-NEXT:              "columnNumber": 16
+// CHECK-NEXT:            }
+// CHECK-NEXT:          ]
+// CHECK-NEXT:        }
+// CHECK-NEXT:        {
+// CHECK-NEXT:          "identifier": "E"
+// CHECK-NEXT:          "accessLevel": "public"
+// CHECK-NEXT:          "importLocations": [
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "bufferIdentifier": "{{.*}}import_infos.swift"
+// CHECK-NEXT:              "linuNumber": 67
+// CHECK-NEXT:              "columnNumber": 15
+// CHECK-NEXT:            }
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "bufferIdentifier": "{{.*}}import_infos.swift"
+// CHECK-NEXT:              "linuNumber": 68
+// CHECK-NEXT:              "columnNumber": 8
+// CHECK-NEXT:            }
+// CHECK-NEXT:          ]
+// CHECK-NEXT:        }
+// CHECK-NEXT:        {
+// CHECK-NEXT:          "identifier": "G"
+// CHECK-NEXT:          "accessLevel": "fileprivate"
+// CHECK-NEXT:          "importLocations": [
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "bufferIdentifier": "{{.*}}import_infos.swift"
+// CHECK-NEXT:              "linuNumber": 70
+// CHECK-NEXT:              "columnNumber": 20
+// CHECK-NEXT:            }
+// CHECK-NEXT:          ]
+// CHECK-NEXT:        }
+// CHECK-NEXT:      ]
+
+internal import C
+
+public import E
+import E
+
+fileprivate import G
+
+private import C
diff --git a/test/ScanDependencies/incompatible-arch.swift b/test/ScanDependencies/incompatible-arch.swift
new file mode 100644
index 0000000000000..58cc7ec916fa4
--- /dev/null
+++ b/test/ScanDependencies/incompatible-arch.swift
@@ -0,0 +1,12 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/inputs/Foo.swiftmodule)
+// RUN: touch %t/inputs/Foo.swiftmodule/i387.swiftmodule
+// RUN: touch %t/inputs/Foo.swiftmodule/ppc65.swiftmodule
+
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/module-cache %s -o %t/deps.json -I %t/inputs -diagnostic-style llvm -scanner-module-validation 2>&1 | %FileCheck %s
+
+// CHECK: error: unable to resolve Swift module dependency to a compatible module: 'Foo'
+// CHECK-DAG: note: found incompatible module '{{.*}}Foo.swiftmodule{{/|\\}}ppc65.swiftmodule': invalid architecture
+// CHECK-DAG: note: found incompatible module '{{.*}}Foo.swiftmodule{{/|\\}}i387.swiftmodule': invalid architecture
+import Foo
diff --git a/test/ScanDependencies/invalid_binary_module_only.swift b/test/ScanDependencies/invalid_binary_module_only.swift
index a53a7c164d77c..f96d1c7e7bba5 100644
--- a/test/ScanDependencies/invalid_binary_module_only.swift
+++ b/test/ScanDependencies/invalid_binary_module_only.swift
@@ -8,6 +8,5 @@
 
 import FooBar
 
-// CHECK: warning: module file '{{.*}}{{/|\\}}moduleInputs{{/|\\}}FooBar.swiftmodule' is incompatible with this Swift compiler: malformed
-// CHECK: error: Unable to find module dependency: 'FooBar'
-
+// CHECK: error: unable to resolve Swift module dependency to a compatible module: 'FooBar'
+// CHECK: note: found incompatible module '{{.*}}{{/|\\}}moduleInputs{{/|\\}}FooBar.swiftmodule': malformed
diff --git a/test/ScanDependencies/module_deps_cache_reuse.swift b/test/ScanDependencies/module_deps_cache_reuse.swift
index fc11cfadb2660..2d2d8eba9a45a 100644
--- a/test/ScanDependencies/module_deps_cache_reuse.swift
+++ b/test/ScanDependencies/module_deps_cache_reuse.swift
@@ -128,7 +128,7 @@ import SubE
 // CHECK: ],
 // CHECK-NEXT: "linkLibraries": [
 // CHECK-NEXT: ],
-// CHECK-NEXT: "details": {
+// CHECK: "details": {
 
 // CHECK: "commandLine": [
 // CHECK: "-compile-module-from-interface"
diff --git a/test/ScanDependencies/module_deps_different_paths_no_reuse.swift b/test/ScanDependencies/module_deps_different_paths_no_reuse.swift
index f0d76411b46d0..a535a68619e47 100644
--- a/test/ScanDependencies/module_deps_different_paths_no_reuse.swift
+++ b/test/ScanDependencies/module_deps_different_paths_no_reuse.swift
@@ -29,7 +29,7 @@ import A
 // CHECK-INITIAL-SCAN:      ],
 // CHECK-INITIAL-SCAN-NEXT:      "linkLibraries": [
 // CHECK-INITIAL-SCAN-NEXT:      ],
-// CHECK-INITIAL-SCAN-NEXT:      "details": {
+// CHECK-INITIAL-SCAN:      "details": {
 // CHECK-INITIAL-SCAN-NEXT:        "swift": {
 // CHECK-INITIAL-SCAN-NEXT:          "moduleInterfacePath": "{{.*}}/Swift/A.swiftinterface",
 
@@ -43,6 +43,6 @@ import A
 // CHECK-DIFFERENT:      ],
 // CHECK-DIFFERENT-NEXT:      "linkLibraries": [
 // CHECK-DIFFERENT-NEXT:      ],
-// CHECK-DIFFERENT-NEXT:      "details": {
+// CHECK-DIFFERENT:      "details": {
 // CHECK-DIFFERENT-NEXT:        "swift": {
 // CHECK-DIFFERENT-NEXT:          "moduleInterfacePath": "{{.*}}/SwiftDifferent/A.swiftinterface",
diff --git a/test/ScanDependencies/module_deps_external.swift b/test/ScanDependencies/module_deps_external.swift
deleted file mode 100644
index 80d0f4bbba3d4..0000000000000
--- a/test/ScanDependencies/module_deps_external.swift
+++ /dev/null
@@ -1,96 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: mkdir -p %t/clang-module-cache
-// RUN: mkdir -p %t/inputs
-
-// RUN: echo "[{" > %/t/inputs/map.json
-// RUN: echo "\"moduleName\": \"SomeExternalModule\"," >> %/t/inputs/map.json
-// RUN: echo "\"modulePath\": \"%/t/inputs/SomeExternalModule.swiftmodule\"," >> %/t/inputs/map.json
-// RUN: echo "\"docPath\": \"%/t/inputs/SomeExternalModule.swiftdoc\"," >> %/t/inputs/map.json
-// RUN: echo "\"sourceInfoPath\": \"%/t/inputs/SomeExternalModule.swiftsourceinfo\"," >> %/t/inputs/map.json
-// RUN: echo "\"isFramework\": false" >> %/t/inputs/map.json
-// RUN: echo "}]" >> %/t/inputs/map.json
-
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -module-cache-path %t/clang-module-cache %s -placeholder-dependency-module-map-file %t/inputs/map.json -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/Inputs/CHeaders/Bridging.h -swift-version 4
-
-// Check the contents of the JSON output
-// RUN: %validate-json %t/deps.json | %FileCheck %s
-
-// Check the make-style dependencies file
-// RUN: %FileCheck %s -check-prefix CHECK-MAKE-DEPS < %t/deps.d
-
-// Check that the JSON parses correctly into the canonical Swift data
-// structures.
-
-// RUN: mkdir -p %t/PrintGraph
-// RUN: cp %S/Inputs/PrintGraph.swift %t/main.swift
-// RUN: %target-build-swift %S/Inputs/ModuleDependencyGraph.swift %t/main.swift -o %t/main
-// RUN: %target-codesign %t/main
-// RUN: %target-run %t/main %t/deps.json
-
-// Ensure that round-trip serialization does not affect result
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -test-dependency-scan-cache-serialization -module-cache-path %t/clang-module-cache %s -placeholder-dependency-module-map-file %t/inputs/map.json -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -import-objc-header %S/Inputs/CHeaders/Bridging.h -swift-version 4
-// RUN: %validate-json %t/deps.json | %FileCheck %s
-
-// REQUIRES: executable_test
-// REQUIRES: objc_interop
-import SomeExternalModule
-
-// CHECK: "mainModuleName": "deps"
-
-/// --------Main module
-// CHECK-LABEL: "modulePath": "deps.swiftmodule",
-// CHECK-NEXT: sourceFiles
-// CHECK-NEXT: module_deps_external.swift
-
-// CHECK: directDependencies
-// CHECK-NEXT: {
-// CHECK-DAG: "clang": "F"
-// CHECK-DAG: "swiftPlaceholder": "SomeExternalModule"
-// CHECK-DAG: "swift": "Swift"
-// CHECK-DAG: "swift": "SwiftOnoneSupport"
-// CHECK-DAG: "swift": "_Concurrency"
-// CHECK-DAG: "swift": "_StringProcessing"
-// CHECK-DAG: "clang": "_SwiftConcurrencyShims"
-// CHECK: ],
-
-// CHECK: "bridgingHeader":
-// CHECK-NEXT: "path":
-// CHECK-SAME: Bridging.h
-
-// CHECK-NEXT: "sourceFiles":
-// CHECK-NEXT: Bridging.h
-// CHECK-NEXT: BridgingOther.h
-
-// CHECK:       "moduleDependencies": [
-// CHECK-NEXT:     "F"
-// CHECK-NEXT:  ],
-
-// CHECK:       "swiftOverlayDependencies": [
-// CHECK-NEXT:    {
-// CHECK-NEXT:      "swift": "F"
-// CHECK-NEXT:    }
-// CHECK-NEXT:  ]
-
-/// --------Swift external module SomeExternalModule
-// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}SomeExternalModule.swiftmodule",
-// CHECK-NEXT: "details": {
-// CHECK-NEXT: "swiftPlaceholder": {
-// CHECK-NEXT: "moduleDocPath": "BUILD_DIR/{{.*}}/ScanDependencies/Output/module_deps_external.swift.tmp/inputs/SomeExternalModule.swiftdoc",
-// CHECK-NEXT: "moduleSourceInfoPath": "BUILD_DIR/{{.*}}/ScanDependencies/Output/module_deps_external.swift.tmp/inputs/SomeExternalModule.swiftsourceinfo"
-
-/// --------Swift module Swift
-// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}Swift-{{.*}}.swiftmodule",
-
-// CHECK: directDependencies
-// CHECK-NEXT: {
-// CHECK-NEXT: "clang": "SwiftShims"
-
-/// --------Clang module SwiftShims
-// CHECK-LABEL: "modulePath": "{{.*}}/SwiftShims-{{.*}}.pcm",
-
-// Check make-style dependencies
-// CHECK-MAKE-DEPS: module_deps_external.swift
-// CHECK-MAKE-DEPS-SAME: Bridging.h
-// CHECK-MAKE-DEPS-SAME: BridgingOther.h
-// CHECK-MAKE-DEPS-SAME: module.modulemap
-
diff --git a/test/ScanDependencies/module_deps_swift_overlay_only_visible.swift b/test/ScanDependencies/module_deps_swift_overlay_only_visible.swift
new file mode 100644
index 0000000000000..eff4edf747f5a
--- /dev/null
+++ b/test/ScanDependencies/module_deps_swift_overlay_only_visible.swift
@@ -0,0 +1,72 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/clang-module-cache)
+// RUN: %empty-directory(%t/swiftDeps)
+// RUN: %empty-directory(%t/clangDeps)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %t/client.swift -o %t/deps.json -I %t/swiftDeps -I %t/clangDeps
+// RUN: %validate-json %t/deps.json | %FileCheck %s
+
+// Ensure Swift module 'E' has a Swift overlay dependency on
+// 'G', because Clang module 'G' is a visible dependency of Clang module 'E'
+//
+// CHECK-LABEL:        "modulePath": "{{.*}}E-{{.*}}.swiftmodule"
+// CHECK:              "swiftOverlayDependencies": [
+// CHECK-NEXT:            {
+// CHECK-NEXT:              "swift": "G"
+// CHECK-NEXT:            }
+// CHECK-NEXT:          ]
+
+// Ensure Swift module 'A' does not have a Swift overlay dependency on
+// 'G', because although 'A' depends on Clang module 'G', it does not export it
+// and therefore it is not visible
+//
+// CHECK:        "modulePath": "{{.*}}A-{{.*}}.swiftmodule"
+// CHECK-NOT:              "swiftOverlayDependencies": [
+
+//--- swiftDeps/A.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name A -enable-library-evolution
+@_exported import A
+public func overlayFuncA() {}
+
+//--- swiftDeps/E.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name E -enable-library-evolution
+@_exported import E
+public func overlayFuncE() {}
+
+//--- swiftDeps/G.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name G -enable-library-evolution
+@_exported import G
+public func overlayFuncG() {}
+
+//--- clangDeps/module.modulemap
+module A {
+  header "A.h"
+  // No export *
+}
+module E {
+  header "E.h"
+  export *
+}
+module G {
+  header "G.h"
+  export *
+}
+
+//--- clangDeps/A.h
+#include "G.h"
+void funcA(void);
+
+//--- clangDeps/E.h
+#include "G.h"
+void funcE(void);
+
+//--- clangDeps/G.h
+void funcG(void);
+
+//--- client.swift
+import A
+import E
diff --git a/test/ScanDependencies/module_deps_swift_overlay_only_visible_cached.swift b/test/ScanDependencies/module_deps_swift_overlay_only_visible_cached.swift
new file mode 100644
index 0000000000000..aefe39de769f0
--- /dev/null
+++ b/test/ScanDependencies/module_deps_swift_overlay_only_visible_cached.swift
@@ -0,0 +1,78 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/clang-module-cache)
+// RUN: %empty-directory(%t/swiftDeps)
+// RUN: %empty-directory(%t/clangDeps)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %t/client.swift -o %t/deps.json -I %t/swiftDeps -I %t/clangDeps
+// RUN: %validate-json %t/deps.json | %FileCheck %s
+
+// Ensure Swift module 'E' has a Swift overlay dependency on
+// 'G', because Clang module 'G' is a visible dependency of Clang module 'E'
+//
+// CHECK-LABEL:        "modulePath": "{{.*}}E-{{.*}}.swiftmodule"
+// CHECK:              "swiftOverlayDependencies": [
+// CHECK-NEXT:            {
+// CHECK-DAG:               "swift": "G"
+// CHECK-DAG:               "swift": "Y"
+// CHECK:                 }
+
+// Ensure Swift module 'G' has a Swift overlay dependency on
+// 'Y', because Clang module 'Y' is a visible dependency of Clang module 'X'
+//
+// CHECK-LABEL:        "modulePath": "{{.*}}G-{{.*}}.swiftmodule"
+
+//--- swiftDeps/E.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name E -enable-library-evolution
+@_exported import E
+public func overlayFuncE() {}
+
+//--- swiftDeps/G.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name G -enable-library-evolution
+@_exported import G
+import X
+public func overlayFuncG() {}
+
+//--- swiftDeps/Y.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name Y -enable-library-evolution
+@_exported import Y
+public func overlayFuncX() {}
+
+//--- clangDeps/module.modulemap
+module E {
+  header "E.h"
+  export *
+}
+module G {
+  header "G.h"
+  export *
+}
+module X {
+  header "X.h"
+  export *
+}
+module Y {
+  header "Y.h"
+  export *
+}
+
+//--- clangDeps/E.h
+#include "G.h";
+#include "X.h";
+void funcE(void);
+
+//--- clangDeps/G.h
+void funcG(void);
+
+//--- clangDeps/X.h
+#include "Y.h";
+void funcX(void);
+
+//--- clangDeps/Y.h
+void funcY(void);
+
+//--- client.swift
+import E
diff --git a/test/ScanDependencies/no-cxx-overlay-for-non-interop-interface.swift b/test/ScanDependencies/no-cxx-overlay-for-non-interop-interface.swift
new file mode 100644
index 0000000000000..ce9c29fbde6c5
--- /dev/null
+++ b/test/ScanDependencies/no-cxx-overlay-for-non-interop-interface.swift
@@ -0,0 +1,131 @@
+
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/deps)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -o %t/deps.json %t/clientWithInteropDep.swift -I %t/deps -cxx-interoperability-mode=default -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -verify
+// RUN: cat %t/deps.json | %FileCheck %s -check-prefix=ENABLE-CHECK
+
+// RUN: %target-swift-frontend -scan-dependencies -o %t/deps_no_interop_dep.json %t/clientNoInteropDep.swift -I %t/deps -cxx-interoperability-mode=default -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -verify
+// RUN: cat %t/deps_no_interop_dep.json | %FileCheck %s -check-prefix=DISABLE-CHECK
+
+// RUN: %target-swift-frontend -emit-module %t/BinaryDepNoInterop.swift -emit-module-path %t/deps/BinaryDepNoInterop.swiftmodule -module-name BinaryDepNoInterop -I %t/deps -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import
+// RUN: %target-swift-frontend -scan-dependencies -o %t/deps_no_interop_binary_dep.json %t/clientNoInteropBinaryDep.swift -I %t/deps -cxx-interoperability-mode=default -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -verify
+// RUN: cat %t/deps_no_interop_binary_dep.json | %FileCheck %s -check-prefix=DISABLE-BINARY-CHECK
+
+// RUN: %target-swift-frontend -scan-dependencies -o %t/deps_darwin_dep.json %t/clientDarwin.swift -I %t/deps -cxx-interoperability-mode=default -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -verify
+// RUN: cat %t/deps_darwin_dep.json | %FileCheck %s -check-prefix=DARWIN-CHECK
+
+//--- deps/bar.h
+void bar(void);
+
+//--- deps/baz.h
+#include "bar.h"
+void baz(void);
+
+//--- deps/module.modulemap
+module std_Bar [system] {
+  header "bar.h"
+  export *
+}
+module normal {
+  header "baz.h"
+  export *
+}
+
+//--- deps/Foo.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name Foo -enable-library-evolution
+import std_Bar
+public struct Foo1 {}
+
+//--- deps/FooNoInterop.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name FooNoInterop -enable-library-evolution
+// swift-module-flags-ignorable: -formal-cxx-interoperability-mode=off
+import std_Bar
+public struct Foo2 {}
+
+//--- deps/Darwin.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name Darwin -enable-library-evolution
+import std_Bar
+public struct Foo3 {}
+
+//--- BinaryDepNoInterop.swift
+import normal
+public struct Foo6 {}
+
+//--- clientWithInteropDep.swift
+import Foo
+
+//--- clientNoInteropDep.swift
+import FooNoInterop
+
+//--- clientNoInteropBinaryDep.swift
+import BinaryDepNoInterop
+
+//--- clientDarwin.swift
+import Darwin
+
+// Ensure that when the 'Foo' dependency was built with C++ interop enabled,
+// it gets the C++ standard library overlay for its 'std_*' dependency
+//
+// 'Foo' as it appears in direct deps
+// ENABLE-CHECK: "swift": "Foo"
+// 'Foo' as it appears in source-import deps
+// ENABLE-CHECK: "swift": "Foo"
+// Actual dependency info node
+// ENABLE-CHECK: "swift": "Foo"
+// ENABLE-CHECK:      "directDependencies": [
+// ENABLE-CHECK:        {
+// ENABLE-CHECK:          "swift": "SwiftOnoneSupport"
+// ENABLE-CHECK:        },
+// ENABLE-CHECK:        {
+// ENABLE-CHECK:          "swift": "CxxStdlib"
+// ENABLE-CHECK:        },
+// ENABLE-CHECK:        {
+// ENABLE-CHECK:          "clang": "std_Bar"
+// ENABLE-CHECK:        }
+// ENABLE-CHECK:      ],
+
+// Ensure that when the 'Foo' dependency was *not* built with C++ interop enabled,
+// it does not get the C++ standard library overlay for its 'std_*' dependency
+//
+// 'Foo' as it appears in direct deps
+// DISABLE-CHECK: "swift": "FooNoInterop"
+// 'Foo' as it appears in source-import deps
+// DISABLE-CHECK: "swift": "FooNoInterop"
+// Actual dependency info node
+// DISABLE-CHECK: "swift": "FooNoInterop"
+// DISABLE-CHECK:      "directDependencies": [
+// DISABLE-CHECK:        {
+// DISABLE-CHECK:          "swift": "SwiftOnoneSupport"
+// DISABLE-CHECK:        },
+// DISABLE-CHECK:        {
+// DISABLE-CHECK:          "clang": "std_Bar"
+// DISABLE-CHECK:        }
+// DISABLE-CHECK:      ],
+
+// DISABLE-BINARY-CHECK: "modulePath": "{{.*}}{{/|\\}}BinaryDepNoInterop.swiftmodule"
+// DISABLE-BINARY-CHECK:      "directDependencies": [
+// DISABLE-BINARY-CHECK-NEXT:        {
+// DISABLE-BINARY-CHECK-NEXT:          "swift": "Swift"
+// DISABLE-BINARY-CHECK-NEXT:        },
+// DISABLE-BINARY-CHECK-NEXT:        {
+// DISABLE-BINARY-CHECK-NEXT:          "swift": "SwiftOnoneSupport"
+// DISABLE-BINARY-CHECK-NEXT:        },
+// DISABLE-BINARY-CHECK-NEXT:        {
+// DISABLE-BINARY-CHECK-NEXT:          "clang": "normal"
+// DISABLE-BINARY-CHECK-NEXT:        }
+// DISABLE-BINARY-CHECK-NEXT:      ],
+
+// DARWIN-CHECK: "modulePath": "{{.*}}{{/|\\}}Darwin-{{.*}}.swiftmodule"
+// DARWIN-CHECK:      "directDependencies": [
+// DARWIN-CHECK-NEXT:        {
+// DARWIN-CHECK-NEXT:          "swift": "SwiftOnoneSupport"
+// DARWIN-CHECK-NEXT:        },
+// DARWIN-CHECK-NEXT:        {
+// DARWIN-CHECK-NEXT:          "clang": "std_Bar"
+// DARWIN-CHECK-NEXT:        }
+// DARWIN-CHECK-NEXT:      ],
diff --git a/test/ScanDependencies/placholder_overlay_deps.swift b/test/ScanDependencies/placholder_overlay_deps.swift
deleted file mode 100644
index 16fa8106d0ccc..0000000000000
--- a/test/ScanDependencies/placholder_overlay_deps.swift
+++ /dev/null
@@ -1,31 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: mkdir -p %t/clang-module-cache
-// RUN: mkdir -p %t/inputs
-
-// RUN: echo "[{" > %/t/inputs/map.json
-// RUN: echo "\"moduleName\": \"Darwin\"," >> %/t/inputs/map.json
-// RUN: echo "\"modulePath\": \"%/t/inputs/Darwin.swiftmodule\"," >> %/t/inputs/map.json
-// RUN: echo "\"docPath\": \"%/t/inputs/Darwin.swiftdoc\"," >> %/t/inputs/map.json
-// RUN: echo "\"sourceInfoPath\": \"%/t/inputs/Darwin.swiftsourceinfo\"," >> %/t/inputs/map.json
-// RUN: echo "\"isFramework\": false," >> %/t/inputs/map.json
-// RUN: echo "\"isSystem\": true" >> %/t/inputs/map.json
-// RUN: echo "}]" >> %/t/inputs/map.json
-
-// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -placeholder-dependency-module-map-file %t/inputs/map.json -o %t/deps.json
-
-// Check the contents of the JSON output
-// RUN: %validate-json %t/deps.json > %t/validated_deps.json
-// RUN: %FileCheck %s < %t/validated_deps.json
-
-// REQUIRES: executable_test
-// REQUIRES: objc_interop
-// REQUIRES: OS=macosx
-import Metal
-
-// Ensure the dependency on Darwin is captured even though it is a placeholder
-
-// CHECK:   "modulePath": "{{.*}}{{/|\\}}Metal-{{.*}}.swiftmodule",
-// CHECK:   "directDependencies": [
-// CHECK:     {
-// CHECK:       "swiftPlaceholder": "Darwin"
-// CHECK:     },
diff --git a/test/ScanDependencies/preserve_used_vfs.swift b/test/ScanDependencies/preserve_used_vfs.swift
index 4aef2c36d45b9..54f3c92fc0492 100644
--- a/test/ScanDependencies/preserve_used_vfs.swift
+++ b/test/ScanDependencies/preserve_used_vfs.swift
@@ -1,17 +1,63 @@
 // REQUIRES: objc_interop
 // RUN: %empty-directory(%t)
 // RUN: %empty-directory(%t/module-cache)
-// RUN: %empty-directory(%t/redirects)
+// RUN: %empty-directory(%t/inputs)
+// RUN: %empty-directory(%t/inputs-2)
 // RUN: split-file %s %t
 
-// RUN: sed -e "s|OUT_DIR|%t/redirects|g"  -e "s|IN_DIR|%S/Inputs/CHeaders|g" %t/overlay_template.yaml > %t/overlay.yaml
+// RUN: sed -e "s|OUT_DIR|%t/redirects|g"  -e "s|IN_DIR|%t/inputs|g" %t/overlay_template.yaml > %t/overlay.yaml
+// RUN: sed -e "s|OUT_DIR|%t/redirects-2|g"  -e "s|IN_DIR|%t/inputs-2|g" %t/overlay_template_2.yaml > %t/overlay-2.yaml
 
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -module-cache-path %t/module-cache %t/test.swift -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -Xcc -ivfsoverlay -Xcc %t/overlay.yaml
+/// Put some files in RealFileSystem that need to be over shadow by VFS.
+// RUN: touch %t/inputs/module.modulemap
+// RUN: touch %t/inputs-2/module.modulemap
+
+// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-serialized -module-cache-path %t/module-cache %t/test.swift -o %t/deps.json -I %t/inputs -I %t/inputs-2 -I %S/Inputs/Swift -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -Xcc -ivfsoverlay -Xcc %t/overlay.yaml -Xcc -ivfsoverlay -Xcc %t/overlay-2.yaml
 // RUN: %validate-json %t/deps.json | %FileCheck %s
 
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json Swift > %t/swift.cmd
+// RUN: %swift_frontend_plain @%t/swift.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json SwiftOnoneSupport > %t/onone.cmd
+// RUN: %swift_frontend_plain @%t/onone.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:Indirect > %t/Indirect.cmd
+// RUN: %swift_frontend_plain @%t/Indirect.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:F > %t/F.cmd
+// RUN: %swift_frontend_plain @%t/F.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json F > %t/SwiftF.cmd
+// RUN: %swift_frontend_plain @%t/SwiftF.cmd
+
+// RUN: %{python} %S/../CAS/Inputs/GenerateExplicitModuleMap.py %t/deps.json > %t/map.json
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json Test > %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-string-processing-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-concurrency-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-swift-modules\"" >> %t/MyApp.cmd
+// RUN: echo "\"-explicit-swift-module-map-file\"" >> %t/MyApp.cmd
+// RUN: echo "\"%t/map.json\"" >> %t/MyApp.cmd
+
+// RUN: %target-swift-frontend @%t/MyApp.cmd %t/test.swift -Xcc -ivfsoverlay -Xcc %t/overlay.yaml -Xcc -ivfsoverlay -Xcc %t/overlay-2.yaml \
+// RUN:   -emit-module -o %t/Test.swiftmodule
+
 //--- redirects/RedirectedF.h
+#include "Indirect_2.h"
 void funcRedirectedF(void);
 
+//--- redirects/modulemap
+module F {
+  header "F_2.h"
+  export *
+}
+
+//--- redirects-2/RedirectedIndirect.h
+void funcRedirectedIndirect(void);
+
+//--- redirects-2/modulemap
+module Indirect {
+  header "Indirect_2.h"
+  export *
+}
+
 //--- overlay_template.yaml
 {
   'version': 0,
@@ -20,8 +66,30 @@ void funcRedirectedF(void);
     {
       'name': 'IN_DIR', 'type': 'directory',
       'contents': [
-        { 'name': 'F.h', 'type': 'file',
+        { 'name': 'F_2.h', 'type': 'file',
           'external-contents': 'OUT_DIR/RedirectedF.h'
+        },
+        { 'name': 'module.modulemap', 'type': 'file',
+          'external-contents': 'OUT_DIR/modulemap'
+        }
+      ]
+    },
+  ]
+}
+
+//--- overlay_template_2.yaml
+{
+  'version': 0,
+  'use-external-names': false,
+  'roots': [
+    {
+      'name': 'IN_DIR', 'type': 'directory',
+      'contents': [
+        { 'name': 'Indirect_2.h', 'type': 'file',
+          'external-contents': 'OUT_DIR/RedirectedIndirect.h'
+        },
+        { 'name': 'module.modulemap', 'type': 'file',
+          'external-contents': 'OUT_DIR/modulemap'
         }
       ]
     },
@@ -31,6 +99,9 @@ void funcRedirectedF(void);
 //--- test.swift
 import F
 
+func testF() { funcRedirectedF() }
+func testIndirect() { funcRedirectedIndirect() }
+
 // CHECK: "mainModuleName": "deps"
 /// --------Main module
 // CHECK-LABEL: "modulePath": "deps.swiftmodule",
@@ -61,6 +132,10 @@ import F
 // CHECK: "-ivfsoverlay",
 // CHECK-NEXT: "-Xcc",
 // CHECK-NEXT: "{{.*}}{{/|\\}}preserve_used_vfs.swift.tmp{{/|\\}}overlay.yaml",
+// CHECK-NEXT: "-Xcc",
+// CHECK-NEXT: "-ivfsoverlay",
+// CHECK-NEXT: "-Xcc",
+// CHECK-NEXT: "{{.*}}{{/|\\}}preserve_used_vfs.swift.tmp{{/|\\}}overlay-2.yaml",
 // CHECK: ],
 
 /// --------Clang module F
@@ -68,7 +143,22 @@ import F
 // CHECK: "commandLine": [
 // CHECK: "-vfsoverlay",
 // CHECK-NEXT: "{{.*}}{{/|\\}}preserve_used_vfs.swift.tmp{{/|\\}}overlay.yaml",
+// CHECK-NEXT: "-vfsoverlay",
+// CHECK-NEXT: "{{.*}}{{/|\\}}preserve_used_vfs.swift.tmp{{/|\\}}overlay-2.yaml",
 // CHECK: "-ivfsoverlay",
 // CHECK-NEXT: "-Xcc",
 // CHECK-NEXT: "{{.*}}{{/|\\}}preserve_used_vfs.swift.tmp{{/|\\}}overlay.yaml",
-// CHECK: ],
+// CHECK-NEXT: "-Xcc",
+// CHECK-NEXT: "-ivfsoverlay",
+// CHECK-NEXT: "-Xcc",
+// CHECK-NEXT: "{{.*}}{{/|\\}}preserve_used_vfs.swift.tmp{{/|\\}}overlay-2.yaml",
+// CHECK: ]
+
+/// --------Clang module Indirect
+// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}Indirect-{{.*}}.pcm",
+// CHECK-NOT: overlay.yaml
+// CHECK: "-vfsoverlay",
+// CHECK-NEXT: "{{.*}}{{/|\\}}preserve_used_vfs.swift.tmp{{/|\\}}overlay-2.yaml",
+// CHECK: "-ivfsoverlay",
+// CHECK-NEXT: "-Xcc",
+// CHECK-NEXT: "{{.*}}{{/|\\}}preserve_used_vfs.swift.tmp{{/|\\}}overlay-2.yaml",
diff --git a/test/ScanDependencies/serialized_imports.swift b/test/ScanDependencies/serialized_imports.swift
new file mode 100644
index 0000000000000..41b3945a715f3
--- /dev/null
+++ b/test/ScanDependencies/serialized_imports.swift
@@ -0,0 +1,55 @@
+// REQUIRES: objc_interop
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+
+// Run the scanner once, emitting the serialized scanner cache
+// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -Rdependency-scan-cache -serialize-dependency-scan-cache -load-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache -module-cache-path %t/module-cache %s -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -enable-cross-import-overlays -module-name deps 2>&1 | %FileCheck %s -check-prefix CHECK-REMARK-SAVE
+// RUN: llvm-bcanalyzer --dump %t/cache.moddepcache > %t/cache.moddepcache.initial.dump.txt
+// RUN: %validate-json %t/deps.json | %FileCheck %s -check-prefix CHECK-IMPORTS
+
+// Run the scanner again, but now re-using previously-serialized cache
+// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -Rdependency-scan-cache -serialize-dependency-scan-cache -load-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache -module-cache-path %t/module-cache %s -o %t/deps_incremental.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -enable-cross-import-overlays -module-name deps 2>&1 | %FileCheck %s -check-prefix CHECK-REMARK-LOAD
+// RUN: llvm-bcanalyzer --dump %t/cache.moddepcache > %t/cache.moddepcache.dump.txt
+// RUN: %validate-json %t/deps_incremental.json | %FileCheck %s -check-prefix CHECK-IMPORTS
+
+// Ensure that the initial scan, and the secondary scan which just re-used the initial scan's results report
+// the same number of import statement nodes, ensuring that serialization-deserialization did not affect
+// the import sets
+//
+// RUN: grep "IMPORT_STATEMENT_NODE" %t/cache.moddepcache.initial.dump.txt | wc -l > %t/initial_scan_import_count.txt
+// RUN: grep "IMPORT_STATEMENT_NODE" %t/cache.moddepcache.dump.txt | wc -l > %t/secondary_scan_import_count.txt
+// RUN: diff %t/initial_scan_import_count.txt %t/secondary_scan_import_count.txt
+
+// CHECK-REMARK-SAVE: remark: Incremental module scan: Failed to load module scanning dependency cache from:
+// CHECK-REMARK-SAVE: remark: Incremental module scan: Serializing module scanning dependency cache to:
+// CHECK-REMARK-LOAD: remark: Incremental module scan: Re-using serialized module scanning dependency cache from:
+
+// CHECK-IMPORTS:      "modulePath": "deps.swiftmodule",
+// CHECK-IMPORTS:      "imports": [
+// CHECK-IMPORTS-NEXT:        {
+// CHECK-IMPORTS-NEXT:          "identifier": "Swift",
+// CHECK-IMPORTS-NEXT:          "accessLevel": "public"
+// CHECK-IMPORTS-NEXT:        },
+// CHECK-IMPORTS-NEXT:        {
+// CHECK-IMPORTS-NEXT:          "identifier": "SwiftOnoneSupport",
+// CHECK-IMPORTS-NEXT:          "accessLevel": "public"
+// CHECK-IMPORTS-NEXT:        },
+// CHECK-IMPORTS-NEXT:        {
+// CHECK-IMPORTS-NEXT:          "identifier": "E",
+// CHECK-IMPORTS-NEXT:          "accessLevel": "public",
+// CHECK-IMPORTS-NEXT:          "importLocations": [
+// CHECK-IMPORTS-NEXT:            {
+// CHECK-IMPORTS-NEXT:              "bufferIdentifier": "{{.*}}serialized_imports.swift",
+// CHECK-IMPORTS-NEXT:              "linuNumber": 54,
+// CHECK-IMPORTS-NEXT:              "columnNumber": 8
+// CHECK-IMPORTS-NEXT:            }
+
+// CHECK-IMPORTS:          "optionalImports": [
+// CHECK-IMPORTS-NEXT:        {
+// CHECK-IMPORTS-NEXT:          "identifier": "E_Private",
+// CHECK-IMPORTS-NEXT:          "accessLevel": "public"
+// CHECK-IMPORTS-NEXT:        }
+// CHECK-IMPORTS-NEXT:      ],
+
+import E
+import E.Private
diff --git a/test/ScanDependencies/source_imports_only.swift b/test/ScanDependencies/source_imports_only.swift
new file mode 100644
index 0000000000000..97fbf29c76348
--- /dev/null
+++ b/test/ScanDependencies/source_imports_only.swift
@@ -0,0 +1,28 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/module-cache %s -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import
+// Check the contents of the JSON output
+// RUN: %validate-json %t/deps.json | %FileCheck %s
+
+// Ensure that round-trip serialization does not affect result
+// RUN: %target-swift-frontend -scan-dependencies -test-dependency-scan-cache-serialization -module-cache-path %t/module-cache %s -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import
+// RUN: %validate-json %t/deps.json | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: objc_interop
+
+import C
+
+// CHECK:          "sourceImportedDependencies": [
+// CHECK-NEXT:      {
+// CHECK-DAG:          "swift": "Swift"
+// CHECK-DAG:          "swift": "SwiftOnoneSupport"
+// CHECK-DAG:          "clang": "C"
+// CHECK-NEXT:      }
+// CHECK-NEXT:    ]
+
+// CHECK:         "swiftOverlayDependencies": [
+// CHECK-NEXT:      {
+// CHECK-NEXT:        "swift": "A"
+// CHECK-NEXT:      }
+// CHECK-NEXT:    ]
diff --git a/test/ScanDependencies/testable-dependencies.swift b/test/ScanDependencies/testable-dependencies.swift
index b43f2c8ac9359..d575287da8793 100644
--- a/test/ScanDependencies/testable-dependencies.swift
+++ b/test/ScanDependencies/testable-dependencies.swift
@@ -50,13 +50,14 @@
 // TEST4:  "swiftPrebuiltExternal": "A"
 // RUN: %{python} %S/../CAS/Inputs/SwiftDepsExtractor.py %t/deps4.json swiftPrebuiltExternal:A directDependencies | %FileCheck %s --check-prefix TEST4-A
 // TEST4-A:  "swift": "B"
+// WARN: warning: module file '{{.*}}{{/|\\}}A.swiftmodule' is incompatible with this Swift compiler: module built without '-enable-testing'
 
 /// Testable import non-testable build enable testing, warning about the finding then error out.
 // RUN: %target-swift-frontend -scan-dependencies -scanner-module-validation -module-load-mode prefer-interface -module-name Test %t/testable.swift \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib -enable-testing \
-// RUN:   -o %t/deps5.json -I %t/regular -swift-version 5 -Rmodule-loading 2>&1 | %FileCheck %s --check-prefix WARN --check-prefix ERROR
-// WARN: warning: ignore swiftmodule built without '-enable-testing'
-// ERROR: error: Unable to find module dependency: 'A'
+// RUN:   -o %t/deps5.json -I %t/regular -swift-version 5 -Rmodule-loading 2>&1 | %FileCheck %s --check-prefix ERROR
+// ERROR: error: unable to resolve Swift module dependency to a compatible module: 'A'
+// ERROR: note: found incompatible module '{{.*}}{{/|\\}}A.swiftmodule': module built without '-enable-testing'
 
 /// Regular import a testable module with no interface, don't load optional dependencies.
 // RUN: rm %t/testable/A.swiftinterface
diff --git a/test/ScanDependencies/wrong_target_candidate_diagnostic.swift b/test/ScanDependencies/wrong_target_candidate_diagnostic.swift
new file mode 100644
index 0000000000000..edcbb4048d658
--- /dev/null
+++ b/test/ScanDependencies/wrong_target_candidate_diagnostic.swift
@@ -0,0 +1,17 @@
+// REQUIRES: OS=macosx
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/moduleInputs)
+// RUN: split-file %s %t
+
+// ERROR: error: unable to resolve Swift module dependency to a compatible module: 'FooBar'
+// ERROR: note: found incompatible module '{{.*}}{{/|\\}}moduleInputs{{/|\\}}FooBar.swiftmodule': compiled for a different target platform
+
+// RUN: %target-swift-frontend -emit-module %t/FooBar.swift -emit-module-path %t/moduleInputs/FooBar.swiftmodule -module-name FooBar -target x86_64-unknown-linux-gnu -parse-stdlib
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %t/main.swift -o %t/deps.json -I %t/moduleInputs -I %t/moduleInputs2 -diagnostic-style llvm -scanner-module-validation -target arm64e-apple-macosx11.0 2>&1 | %FileCheck %s -check-prefix=ERROR
+
+//--- main.swift
+import FooBar
+
+//--- FooBar.swift
+public func fooBar() {}
diff --git a/test/Sema/Inputs/conformance_availability_implied_other.swift b/test/Sema/Inputs/conformance_availability_implied_other.swift
new file mode 100644
index 0000000000000..7e045ec5cbea0
--- /dev/null
+++ b/test/Sema/Inputs/conformance_availability_implied_other.swift
@@ -0,0 +1,8 @@
+
+@available(macOS 200, *)
+extension Conformer1: Derived2 {}
+
+@available(macOS 100, *)
+extension Conformer2: Derived1 {}
+// expected-error@-1 {{conformance of 'Conformer2' to 'Base' is only available in macOS 200 or newer}}
+
diff --git a/test/Sema/Inputs/lifetime_depend_infer.swiftinterface b/test/Sema/Inputs/lifetime_depend_infer.swiftinterface
index d4776fcf1106e..2ae5b414f7b66 100644
--- a/test/Sema/Inputs/lifetime_depend_infer.swiftinterface
+++ b/test/Sema/Inputs/lifetime_depend_infer.swiftinterface
@@ -1,352 +1,289 @@
 // swift-interface-format-version: 1.0
-// swift-compiler-version: Swift version 6.2-dev effective-5.10 (LLVM 09f3cd831902283, Swift 889522485775a5d)
-// swift-module-flags: -module-name lifetime_depend_infer -enable-experimental-feature LifetimeDependence -swift-version 5 -enable-library-evolution
-// swift-module-flags-ignorable:  -formal-cxx-interoperability-mode=off -interface-compiler-version 6.2
+// swift-module-flags: -module-name lifetime_depend_infer -enable-experimental-feature Lifetimes -swift-version 5 -enable-library-evolution
 import Swift
 import _Concurrency
 import _StringProcessing
 import _SwiftConcurrencyShims
+
 @_hasMissingDesignatedInitializers public class C {}
+
+#if $LifetimeDependence
 public struct NE : ~Swift.Escapable {
 }
 public struct NEImmortal : ~Swift.Escapable {
-  #if $LifetimeDependence
-  @lifetime(immortal)
+  @_lifetime(immortal)
   public init()
-  #endif
+
 }
+
 public struct NonEscapableSelf : ~Swift.Escapable {
-  #if $LifetimeDependence
   public func methodNoParam() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public func methodNoParamLifetime() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(copy self)
+  
+  @_lifetime(copy self)
   public func methodNoParamCopy() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(borrow self)
   public func methodNoParamBorrow() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public mutating func mutatingMethodNoParamLifetime() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(copy self)
+  
+  @_lifetime(copy self)
   public mutating func mutatingMethodNoParamCopy() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(&self)
   public mutating func mutatingMethodNoParamBorrow() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   public func methodOneParam(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public func methodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(copy self)
+  
+  @_lifetime(copy self)
   public func methodOneParamCopy(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(borrow self)
   public func methodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public mutating func mutatingMethodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(copy self)
+  
+  @_lifetime(copy self)
   public mutating func mutatingMethodOneParamCopy(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
-  @lifetime(borrow self)
-  public mutating func mutatingMethodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
+  
+  @_lifetime(&self)
+  public mutating func mutatingMethodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf 
+}
+
+public struct NoncopyableInoutMethods : ~Swift.Copyable & ~Swift.Escapable {
+  public mutating func mutatingMethodOneParamFunctionType<E, Result>(_ body: (Swift.Int) throws(E) -> Result) throws(E) -> Result where E : Swift.Error, Result : ~Swift.Copyable
+
+  public subscript(position: Swift.Int) -> Swift.Int {
+    unsafeAddress
+    unsafeMutableAddress
+  }
 }
+
 public struct EscapableTrivialSelf {
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(self)
+  @_lifetime(self)
   public func methodNoParamLifetime() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(borrow self)
   public func methodNoParamBorrow() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public mutating func mutatingMethodNoParamLifetime() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(&self)
   public mutating func mutatingMethodNoParamBorrow() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public func methodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(borrow self)
   public func methodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public mutating func mutatingMethodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(&self)
   public mutating func mutatingMethodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
+  
 }
 public struct EscapableNonTrivialSelf {
   public init(c: lifetime_depend_infer.C)
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
   public func methodNoParam() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public func methodNoParamLifetime() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(borrow self)
   public func methodNoParamBorrow() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   public func mutatingMethodNoParam() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public mutating func mutatingMethodNoParamLifetime() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(&self)
   public mutating func mutatingMethodNoParamBorrow() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   public func methodOneParam(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public func methodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(borrow self)
   public func methodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   public mutating func mutatingMethodOneParam(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(self)
+  
+  @_lifetime(self)
   public mutating func mutatingMethodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(&self)
   public mutating func mutatingMethodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
+  
 }
 public struct NonescapableInitializers : ~Swift.Escapable {
   public var c: lifetime_depend_infer.C
-  #if $LifetimeDependence
   public init(ne: lifetime_depend_infer.NE)
-  #endif
+  
 }
 public struct NonescapableConsumingInitializers : ~Swift.Escapable {
   public var c: lifetime_depend_infer.C
-  #if $LifetimeDependence
   public init(ne: consuming lifetime_depend_infer.NE)
-  #endif
+  
 }
 public struct NonescapableBorrowingInitializers : ~Swift.Escapable {
   public var c: lifetime_depend_infer.C
-  #if $LifetimeDependence
   public init(c: borrowing lifetime_depend_infer.C)
-  #endif
-  #if $LifetimeDependence
+  
   public init(c: borrowing lifetime_depend_infer.C, _: Swift.Int)
-  #endif
-  #if $LifetimeDependence
+  
   public init(ne: borrowing lifetime_depend_infer.NE)
-  #endif
+  
 }
 public struct NonescapableInoutInitializers : ~Swift.Escapable {
   public var c: lifetime_depend_infer.C
-  #if $LifetimeDependence
   public init(c: inout lifetime_depend_infer.C)
-  #endif
+  
 }
-#if $LifetimeDependence
-@lifetime(immortal)
+@_lifetime(immortal)
 public func noParamImmortal() -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
-@lifetime(c)
+
+@_lifetime(c)
 public func oneParamLifetime(c: lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 public func oneParamBorrow(c: borrowing lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
-@lifetime(c)
+
+@_lifetime(c)
 public func oneParamBorrowLifetime(c: borrowing lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 public func oneParamInout(c: inout lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
-@lifetime(c)
+
+@_lifetime(c)
 public func oneParamInoutLifetime(c: inout lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
-@lifetime(c)
+
+@_lifetime(c)
 public func twoParamsLifetime(c: lifetime_depend_infer.C, _: Swift.Int) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 public func twoParamsBorrow(c: borrowing lifetime_depend_infer.C, _: Swift.Int) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 public func neParam(ne: lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
-@lifetime(ne)
+
+@_lifetime(ne)
 public func neParamLifetime(ne: lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
+
 public func neParamBorrow(ne: borrowing lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
-@lifetime(ne)
+
+@_lifetime(ne)
 public func neParamBorrowLifetime(ne: borrowing lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
+
 public func neParamConsume(ne: consuming lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
-@lifetime(ne)
+
+@_lifetime(ne)
 public func neParamConsumeLifetime(ne: consuming lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
+
 public func neTwoParam(ne: lifetime_depend_infer.NE, _: Swift.Int) -> lifetime_depend_infer.NE
-#endif
+
 public struct Accessors {
-  #if $LifetimeDependence
   public var neYielded: lifetime_depend_infer.NEImmortal {
     _read
     _modify
   }
-  #endif
+  
 }
 public struct NonescapableSelfAccessors : ~Swift.Escapable {
   public var ne: lifetime_depend_infer.NE
-  #if $LifetimeDependence
   public init(ne: lifetime_depend_infer.NE)
-  #endif
-  #if $LifetimeDependence
+  
   public var neComputed: lifetime_depend_infer.NE {
     get
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYielded: lifetime_depend_infer.NE {
     _read
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify
   }
-  #endif
+  
 }
 public struct NoncopyableSelfAccessors : ~Copyable & ~Escapable {
   public var ne: lifetime_depend_infer.NE
-  #if $LifetimeDependence
   public var neComputed: lifetime_depend_infer.NE {
     get
     set
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYielded: lifetime_depend_infer.NE {
     _read
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neComputedLifetime: lifetime_depend_infer.NE {
-    @lifetime(self)
+    @_lifetime(self)
     get
-    @lifetime(self)
+    @_lifetime(self)
     set
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYieldedLifetime: lifetime_depend_infer.NE {
-    @lifetime(self)
+    @_lifetime(self)
     _read
-    @lifetime(self)
+    @_lifetime(self)
     _modify
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neComputedCopy: lifetime_depend_infer.NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     get
-    @lifetime(copy self)
+    @_lifetime(copy self)
     set
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYieldedCopy: lifetime_depend_infer.NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _modify
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neComputedBorrow: lifetime_depend_infer.NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     get
-    @lifetime(borrow self)
+    @_lifetime(&self)
     set
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYieldedBorrow: lifetime_depend_infer.NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     _read
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify
   }
-  #endif
 }
+
 public struct NonEscapableMutableSelf : ~Swift.Escapable {
-  #if $LifetimeDependence
   public mutating func mutatingMethodNoParam()
-  #endif
-  #if $LifetimeDependence
-  @lifetime(self: self)
+  
+  @_lifetime(self: self)
   public mutating func mutatingMethodNoParamLifetime()
-  #endif
-  #if $LifetimeDependence
-  @lifetime(self: copy self)
+  
+  @_lifetime(self: copy self)
   public mutating func mutatingMethodNoParamCopy()
-  #endif
-  #if $LifetimeDependence
-  @lifetime(self: self)
+  
+  @_lifetime(self: self)
   public mutating func mutatingMethodOneParamLifetime(_: lifetime_depend_infer.NE)
-  #endif
-  #if $LifetimeDependence
-  @lifetime(copy self)
+  
+  @_lifetime(copy self)
   public mutating func mutatingMethodOneParamCopy(_: lifetime_depend_infer.NE)
-  #endif
-  #if $LifetimeDependence
-  @lifetime(borrow self)
+  
+  @_lifetime(&self)
   public mutating func mutatingMethodOneParamBorrow(_: lifetime_depend_infer.NE)
-  #endif
 }
+#endif
diff --git a/test/Sema/access-level-and-non-resilient-import.swift b/test/Sema/access-level-and-non-resilient-import.swift
index 8036c12957b99..b0d5d13599605 100644
--- a/test/Sema/access-level-and-non-resilient-import.swift
+++ b/test/Sema/access-level-and-non-resilient-import.swift
@@ -13,24 +13,25 @@
 // RUN: %target-swift-frontend -emit-module %t/PrivateLib.swift -o %t
 
 /// A resilient client will error on public imports.
-/// Keep AccessLevelOnImport to get the error from Swift 6 in Swift 5.
+/// Use AccessLevelOnImport or InternalImportsByDefault to get the error
+/// from Swift 7 in Swift 5.
 // RUN: %target-swift-frontend -typecheck %t/Client_Swift5.swift -I %t \
 // RUN:   -enable-library-evolution -swift-version 5 \
 // RUN:   -enable-experimental-feature AccessLevelOnImport -verify \
-// RUN:   -package-name pkg
-// RUN: %target-swift-frontend -typecheck %t/Client_Swift6.swift -I %t \
+// RUN:   -package-name pkg -library-level api
+// RUN: %target-swift-frontend -typecheck %t/Client_Swift7.swift -I %t \
 // RUN:   -enable-library-evolution \
 // RUN:   -enable-upcoming-feature InternalImportsByDefault \
-// RUN:   -verify -package-name pkg
+// RUN:   -verify -package-name pkg -library-level api
 
 /// A non-resilient client doesn't complain.
 // RUN: %target-swift-frontend -typecheck %t/Client_Swift5.swift -I %t \
 // RUN:   -swift-version 5 \
 // RUN:   -enable-experimental-feature AccessLevelOnImport \
-// RUN:   -package-name pkg
-// RUN: %target-swift-frontend -typecheck %t/Client_Swift6.swift -I %t \
+// RUN:   -package-name pkg -library-level api
+// RUN: %target-swift-frontend -typecheck %t/Client_Swift7.swift -I %t \
 // RUN:   -enable-upcoming-feature InternalImportsByDefault \
-// RUN:   -package-name pkg
+// RUN:   -package-name pkg -library-level api
 
 // REQUIRES: swift_feature_AccessLevelOnImport
 // REQUIRES: swift_feature_InternalImportsByDefault
@@ -53,10 +54,10 @@ internal import InternalLib
 fileprivate import FileprivateLib
 private import PrivateLib
 
-//--- Client_Swift6.swift
+//--- Client_Swift7.swift
 
 import DefaultLib
-public import PublicLib // expected-error {{module 'PublicLib' was not compiled with library evolution support; using it means binary compatibility for 'Client_Swift6' can't be guaranteed}} {{1-8=}}
+public import PublicLib // expected-error {{module 'PublicLib' was not compiled with library evolution support; using it means binary compatibility for 'Client_Swift7' can't be guaranteed}} {{1-8=}}
 // expected-warning @-1 {{public import of 'PublicLib' was not used in public declarations or inlinable code}}
 package import PackageLib
 // expected-warning @-1 {{package import of 'PackageLib' was not used in package declarations}}
diff --git a/test/Sema/access-level-import-classic-exportability.swift b/test/Sema/access-level-import-classic-exportability.swift
index 4720bc8f6f9bf..c59424187f4ab 100644
--- a/test/Sema/access-level-import-classic-exportability.swift
+++ b/test/Sema/access-level-import-classic-exportability.swift
@@ -16,13 +16,13 @@
 /// Check diagnostics.
 // RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
 // RUN:   -package-name TestPackage -swift-version 5 \
-// RUN:   -enable-experimental-feature AccessLevelOnImport -verify
+// RUN:   -enable-experimental-feature AccessLevelOnImport -verify -verify-ignore-unrelated
 
 /// Check diagnostics with library-evolution.
 // RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
 // RUN:   -package-name TestPackage -swift-version 5 \
 // RUN:   -enable-library-evolution \
-// RUN:   -enable-experimental-feature AccessLevelOnImport -verify
+// RUN:   -enable-experimental-feature AccessLevelOnImport -verify -verify-ignore-unrelated
 
 // REQUIRES: swift_feature_AccessLevelOnImport
 
diff --git a/test/Sema/access-level-import-conforming-types.swift b/test/Sema/access-level-import-conforming-types.swift
index ca417cc06426e..b19e298b30324 100644
--- a/test/Sema/access-level-import-conforming-types.swift
+++ b/test/Sema/access-level-import-conforming-types.swift
@@ -8,9 +8,9 @@
 // RUN:  %S/Inputs/implementation-only-import-in-decls-helper.swift -I %t \
 // RUN:  -enable-library-evolution -swift-version 5
 
-// RUN: %target-typecheck-verify-swift -I %t \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t \
 // RUN:  -swift-version 5 -package-name pkg -enable-library-evolution
-// RUN: %target-typecheck-verify-swift -I %t \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t \
 // RUN:  -swift-version 5 -package-name pkg
 
 internal import BADLibrary // expected-note 9 {{protocol 'BadProto' imported as 'internal' from 'BADLibrary' here}}
diff --git a/test/Sema/access-level-import-diag-priority.swift b/test/Sema/access-level-import-diag-priority.swift
index fe127f3b351d5..39c88631612bb 100644
--- a/test/Sema/access-level-import-diag-priority.swift
+++ b/test/Sema/access-level-import-diag-priority.swift
@@ -14,11 +14,11 @@
 
 /// Check diagnostics.
 // RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
-// RUN:   -package-name pkg -verify
+// RUN:   -package-name pkg -verify -verify-ignore-unrelated
 // RUN: %target-swift-frontend -typecheck %t/PackageTypeImportedAsPackageClient.swift -I %t \
-// RUN:   -package-name pkg -verify
+// RUN:   -package-name pkg -verify -verify-ignore-unrelated
 // RUN: %target-swift-frontend -typecheck %t/LocalVsImportClient.swift -I %t \
-// RUN:   -package-name pkg -verify
+// RUN:   -package-name pkg -verify -verify-ignore-unrelated
 
 //--- PublicLib.swift
 public struct PublicImportType {}
diff --git a/test/Sema/access-level-import-exportability.swift b/test/Sema/access-level-import-exportability.swift
index 68f0dc2116cf1..d40af48a650ac 100644
--- a/test/Sema/access-level-import-exportability.swift
+++ b/test/Sema/access-level-import-exportability.swift
@@ -15,17 +15,17 @@
 
 /// Check diagnostics.
 // RUN: %target-swift-frontend -typecheck %t/MinimalClient.swift -I %t \
-// RUN:   -package-name TestPackage -swift-version 5 -verify
+// RUN:   -package-name TestPackage -swift-version 5 -verify -verify-ignore-unrelated
 // RUN: %target-swift-frontend -typecheck %t/CompletenessClient.swift -I %t \
-// RUN:   -package-name TestPackage -swift-version 5 -verify
+// RUN:   -package-name TestPackage -swift-version 5 -verify -verify-ignore-unrelated
 
 /// Check diagnostics with library-evolution.
 // RUN: %target-swift-frontend -typecheck %t/MinimalClient.swift -I %t \
 // RUN:   -package-name TestPackage -swift-version 5 \
-// RUN:   -enable-library-evolution -verify
+// RUN:   -enable-library-evolution -verify -verify-ignore-unrelated
 // RUN: %target-swift-frontend -typecheck %t/CompletenessClient.swift -I %t \
 // RUN:   -package-name TestPackage -swift-version 5 \
-// RUN:   -enable-library-evolution -verify
+// RUN:   -enable-library-evolution -verify -verify-ignore-unrelated
 
 //--- PublicLib.swift
 public protocol PublicImportProto {
diff --git a/test/Sema/access-level-import-inconsistencies.swift b/test/Sema/access-level-import-inconsistencies.swift
index a9b642f70f5ef..581389612da67 100644
--- a/test/Sema/access-level-import-inconsistencies.swift
+++ b/test/Sema/access-level-import-inconsistencies.swift
@@ -78,10 +78,10 @@ public import Lib // expected-warning {{public import of 'Lib' was not used in p
 
 /// Don't report inconsistencies from a file generated by Xcode.
 // RUN: %target-swift-frontend -typecheck -I %t \
-// RUN    -primary-file %t/GeneratedAssetSymbols.swift \
+// RUN:    -primary-file %t/GeneratedAssetSymbols.swift \
 // RUN:   %t/UserWrittenFile.swift -verify
 // RUN: %target-swift-frontend -typecheck -I %t \
-// RUN    %t/GeneratedAssetSymbols.swift \
+// RUN:    %t/GeneratedAssetSymbols.swift \
 // RUN:   -primary-file %t/UserWrittenFile.swift -verify
 
 // REQUIRES: swift_feature_InternalImportsByDefault
diff --git a/test/Sema/access-level-import-inlinable.swift b/test/Sema/access-level-import-inlinable.swift
index 78fed01e4ad73..c54abd6f68d37 100644
--- a/test/Sema/access-level-import-inlinable.swift
+++ b/test/Sema/access-level-import-inlinable.swift
@@ -18,7 +18,7 @@
 
 /// Check diagnostics.
 // RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
-// RUN:   -enable-library-evolution -swift-version 5 -verify \
+// RUN:   -enable-library-evolution -swift-version 5 -verify -verify-ignore-unrelated \
 // RUN:   -package-name package
 
 //--- PublicLib.swift
diff --git a/test/Sema/access-level-import-typealias.swift b/test/Sema/access-level-import-typealias.swift
index d13f0b50f46ef..064464f128fcf 100644
--- a/test/Sema/access-level-import-typealias.swift
+++ b/test/Sema/access-level-import-typealias.swift
@@ -7,9 +7,9 @@
 // RUN: %target-swift-emit-module-interface(%t/Aliases.swiftinterface) %t/Aliases.swift -I %t
 // RUN: %target-swift-typecheck-module-from-interface(%t/Aliases.swiftinterface) -I %t
 
-// RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesNoImport.swift -I %t \
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/UsesAliasesNoImport.swift -I %t \
 // RUN:   -swift-version 5 -enable-library-evolution
-// RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesNoImport.swift -I %t \
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/UsesAliasesNoImport.swift -I %t \
 // RUN:   -swift-version 5 -enable-library-evolution \
 // RUN:   -enable-upcoming-feature InternalImportsByDefault
 
diff --git a/test/Sema/access-notes-invalid.swift b/test/Sema/access-notes-invalid.swift
index e722e244c002c..a4b0bd497d3bd 100644
--- a/test/Sema/access-notes-invalid.swift
+++ b/test/Sema/access-notes-invalid.swift
@@ -21,10 +21,10 @@ class Extant {
   // GOOD-REMARK-DAG: note: add '@objc' explicitly to silence this warning
 
   func bad(_: Int?) {} // expected-remark * {{}}
-  // BAD-IGNORE-NOT: access-notes-invalid.swift:[[@LINE-1]]:{{[0-9]+}}: remark: ignored access note: method cannot be marked @objc by an access note because the type of the parameter cannot be represented in Objective-C; did not implicitly add '@objc' to this instance method, even though it was specified by access note for Access notes containing future, unknown syntax
-  // BAD-IGNORE-NOT: access-notes-invalid.swift:[[@LINE-2]]:{{[0-9]+}}: error: ignored access note: method cannot be marked @objc by an access note because the type of the parameter cannot be represented in Objective-C; did not implicitly add '@objc' to this instance method, even though it was specified by access note for Access notes containing future, unknown syntax
-  // BAD-REMARK-DAG: access-notes-invalid.swift:[[@LINE-3]]:{{[0-9]+}}: remark: ignored access note: method cannot be marked @objc by an access note because the type of the parameter cannot be represented in Objective-C; did not implicitly add '@objc' to this instance method, even though it was specified by access note for Access notes containing future, unknown syntax
-  // BAD-ERROR-DAG: access-notes-invalid.swift:[[@LINE-4]]:{{[0-9]+}}: error: ignored access note: method cannot be marked @objc by an access note because the type of the parameter cannot be represented in Objective-C; did not implicitly add '@objc' to this instance method, even though it was specified by access note for Access notes containing future, unknown syntax
+  // BAD-IGNORE-NOT: access-notes-invalid.swift:[[@LINE-1]]:{{[0-9]+}}: remark: ignored access note: instance method cannot be marked '@objc' by an access note because the type of the parameter cannot be represented in Objective-C; did not implicitly add '@objc' to this instance method, even though it was specified by access note for Access notes containing future, unknown syntax
+  // BAD-IGNORE-NOT: access-notes-invalid.swift:[[@LINE-2]]:{{[0-9]+}}: error: ignored access note: instance method cannot be marked '@objc' by an access note because the type of the parameter cannot be represented in Objective-C; did not implicitly add '@objc' to this instance method, even though it was specified by access note for Access notes containing future, unknown syntax
+  // BAD-REMARK-DAG: access-notes-invalid.swift:[[@LINE-3]]:{{[0-9]+}}: remark: ignored access note: instance method cannot be marked '@objc' by an access note because the type of the parameter cannot be represented in Objective-C; did not implicitly add '@objc' to this instance method, even though it was specified by access note for Access notes containing future, unknown syntax
+  // BAD-ERROR-DAG: access-notes-invalid.swift:[[@LINE-4]]:{{[0-9]+}}: error: ignored access note: instance method cannot be marked '@objc' by an access note because the type of the parameter cannot be represented in Objective-C; did not implicitly add '@objc' to this instance method, even though it was specified by access note for Access notes containing future, unknown syntax
 }
 
 // FIXME: Should diagnose multiple access notes for the same decl
diff --git a/test/Sema/accessibility.swift b/test/Sema/accessibility.swift
index a766532be8c1b..49d28c12edbdc 100644
--- a/test/Sema/accessibility.swift
+++ b/test/Sema/accessibility.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-objc-interop -disable-objc-attr-requires-foundation-module -swift-version 5 -package-name mylib
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-objc-interop -disable-objc-attr-requires-foundation-module -swift-version 5 -package-name mylib
 
 /// Test structs with protocols and extensions
 public protocol PublicProto {
diff --git a/test/Sema/accessibility_multi_module.swift b/test/Sema/accessibility_multi_module.swift
index 610da6b7043b1..75cd815dfbfb5 100644
--- a/test/Sema/accessibility_multi_module.swift
+++ b/test/Sema/accessibility_multi_module.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -primary-file %S/Inputs/accessibility_multi_other_module.swift -emit-module-path %t/accessibility_multi_other_module.swiftmodule
-// RUN: %target-swift-frontend -typecheck -I %t -primary-file %s -verify -verify-ignore-unknown
+// RUN: %target-swift-frontend -typecheck -I %t -primary-file %s -verify -verify-ignore-unrelated -verify-ignore-unknown
 
 import accessibility_multi_other_module
 
diff --git a/test/Sema/accessibility_package.swift b/test/Sema/accessibility_package.swift
index b3254d3fda15a..13234b392b3ff 100644
--- a/test/Sema/accessibility_package.swift
+++ b/test/Sema/accessibility_package.swift
@@ -1,16 +1,16 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
-// RUN: %target-swift-frontend -verify -module-name Utils %t/Utils.swift -emit-module -emit-module-path %t/Utils.swiftmodule -package-name myLib
+// RUN: %target-swift-frontend -verify -verify-ignore-unrelated -module-name Utils %t/Utils.swift -emit-module -emit-module-path %t/Utils.swiftmodule -package-name myLib
 // RUN: test -f %t/Utils.swiftmodule
 
-// RUN: %target-swift-frontend -verify -module-name LibGood %t/LibGood.swift -emit-module -emit-module-path %t/LibGood.swiftmodule -package-name myLib -I %t
+// RUN: %target-swift-frontend -verify -verify-ignore-unrelated -module-name LibGood %t/LibGood.swift -emit-module -emit-module-path %t/LibGood.swiftmodule -package-name myLib -I %t
 // RUN: test -f %t/LibGood.swiftmodule
 
-// RUN: %target-swift-frontend -verify -module-name Client %t/Client.swift -emit-module -emit-module-path %t/Client.swiftmodule -package-name client -I %t
+// RUN: %target-swift-frontend -verify -verify-ignore-unrelated -module-name Client %t/Client.swift -emit-module -emit-module-path %t/Client.swiftmodule -package-name client -I %t
 
-// RUN: %target-swift-frontend -typecheck -verify %t/LibSamePackage.swift -package-name myLib -I %t
-// RUN: %target-swift-frontend -typecheck -verify %t/LibOtherPackage.swift -package-name "otherLib" -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/LibSamePackage.swift -package-name myLib -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/LibOtherPackage.swift -package-name "otherLib" -I %t
 
 //--- Utils.swift
 package protocol PackageProto {
diff --git a/test/Sema/accessibility_package_import_interface.swift b/test/Sema/accessibility_package_import_interface.swift
index 58def57073665..01d5065c09af0 100644
--- a/test/Sema/accessibility_package_import_interface.swift
+++ b/test/Sema/accessibility_package_import_interface.swift
@@ -44,7 +44,7 @@
 // CHECK-DEP-INTER-BC: <MODULE_PACKAGE_NAME abbrevid=7/> blob data = 'myPkg'
 
 // TEST Lib should error on loading Dep built from interface and accessing package symbols (unless usableFromInline or inlinable)
-// RUN: %target-swift-frontend -typecheck %t/Lib.swift -package-name myPkg -I %t -verify
+// RUN: %target-swift-frontend -typecheck %t/Lib.swift -package-name myPkg -I %t -verify -verify-ignore-unrelated
 
 // TEST Remove and rebuild Dep from source
 // RUN: rm %t/Dep.swiftmodule
@@ -64,7 +64,7 @@
 // RUN:   -emit-private-module-interface-path %t/LibPass.private.swiftinterface
 
 // TEST Loading LibPass and accessing lib func should pass
-// RUN: %target-swift-frontend -typecheck %t/Client.swift -package-name myPkg -I %t -verify
+// RUN: %target-swift-frontend -typecheck %t/Client.swift -package-name myPkg -I %t -verify -verify-ignore-unrelated
 
 // TEST Building LibPass from interface with Dep (built from interface) should succeed with or without package name
 // Without package name
diff --git a/test/Sema/accessibility_private.swift b/test/Sema/accessibility_private.swift
index 2d3f5c80b1463..df6e7ac3fb00f 100644
--- a/test/Sema/accessibility_private.swift
+++ b/test/Sema/accessibility_private.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 4
 
 class Container {
   private func foo() {} // expected-note * {{declared here}}
diff --git a/test/Sema/atomic-diagnose-var.swift b/test/Sema/atomic-diagnose-var.swift
index ad70124221e51..4e68d947c7211 100644
--- a/test/Sema/atomic-diagnose-var.swift
+++ b/test/Sema/atomic-diagnose-var.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-availability-checking
 // REQUIRES: synchronization
 
 import Synchronization
diff --git a/test/Sema/availability.swift b/test/Sema/availability.swift
deleted file mode 100644
index 0935579ff6ae0..0000000000000
--- a/test/Sema/availability.swift
+++ /dev/null
@@ -1,88 +0,0 @@
-// RUN: %target-typecheck-verify-swift -parse-as-library -module-name MyModule
-
-@available(*, unavailable)
-func unavailable_foo() {} // expected-note {{'unavailable_foo()' has been explicitly marked unavailable here}}
-
-@_unavailableInEmbedded // no-op without -enable-experimental-feature Embedded
-public func unavailable_in_embedded() { }
-
-func test() {
-  unavailable_foo() // expected-error {{'unavailable_foo()' is unavailable}}
-  unavailable_in_embedded() // ok
-}
-
-@available(*,unavailable,message: "use 'Int' instead")
-struct NSUInteger {} // expected-note 3 {{explicitly marked unavailable here}}
-
-struct Outer {
-  @available(*,unavailable,message: "use 'UInt' instead")
-  struct NSUInteger {} // expected-note 2 {{explicitly marked unavailable here}}
-}
-
-func foo(x : NSUInteger) { // expected-error {{'NSUInteger' is unavailable: use 'Int' instead}}
-     let y : NSUInteger = 42 // expected-error {{'NSUInteger' is unavailable: use 'Int' instead}}
-     // expected-error@-1 {{cannot convert value of type 'Int' to specified type 'NSUInteger'}}
-
-  let z : MyModule.NSUInteger = 42 // expected-error {{'NSUInteger' is unavailable: use 'Int' instead}}
-  // expected-error@-1 {{cannot convert value of type 'Int' to specified type 'NSUInteger'}}
-
-  let z2 : Outer.NSUInteger = 42 // expected-error {{'NSUInteger' is unavailable: use 'UInt' instead}}
-  // expected-error@-1 {{cannot convert value of type 'Int' to specified type 'Outer.NSUInteger'}}
-
-  let z3 : MyModule.Outer.NSUInteger = 42 // expected-error {{'NSUInteger' is unavailable: use 'UInt' instead}}
-  // expected-error@-1 {{cannot convert value of type 'Int' to specified type 'Outer.NSUInteger'}}
-}
-
-struct VarToFunc {
-  @available(*, unavailable, renamed: "function()")
-  var variable: Int { // expected-note 2 {{explicitly marked unavailable here}}
-    get { 0 }
-    set {}
-  }
-
-  @available(*, unavailable, renamed: "function()")
-  func oldFunction() -> Int { return 42 } // expected-note 2 {{explicitly marked unavailable here}}
-
-  func function() -> Int {
-    _ = variable // expected-error{{'variable' has been renamed to 'function()'}}{{9-17=function()}}
-    _ = oldFunction() //expected-error{{'oldFunction()' has been renamed to 'function()'}}{{9-20=function}}
-    _ = oldFunction // expected-error{{'oldFunction()' has been renamed to 'function()'}} {{9-20=function}}
-
-    return 42
-  }
-
-  mutating func testAssignment() {
-    // This is nonsense, but someone shouldn't be using 'renamed' for this
-    // anyway. Just make sure we don't crash or anything.
-    variable = 2 // expected-error {{'variable' has been renamed to 'function()'}} {{5-13=function()}}
-  }
-}
-
-struct DeferBody {
-  func foo() {
-    enum No: Error {
-      case no
-    }
-
-    defer {
-      do {
-        throw No.no
-      } catch No.no {
-      } catch {
-      }
-    }
-    _ = ()
-  }
-
-  func bar() {
-    @available(*, unavailable)
-    enum No: Error { // expected-note 2 {{'No' has been explicitly marked unavailable here}}
-      case no
-    }
-    do {
-      throw No.no
-      // expected-error@-1 {{'No' is unavailable}}
-    } catch No.no {} catch _ {}
-    // expected-error@-1 {{'No' is unavailable}}
-  }
-}
diff --git a/test/Sema/availability_custom_domains.swift b/test/Sema/availability_custom_domains.swift
deleted file mode 100644
index 4caac2ec87824..0000000000000
--- a/test/Sema/availability_custom_domains.swift
+++ /dev/null
@@ -1,195 +0,0 @@
-// RUN: %target-typecheck-verify-swift \
-// RUN:  -enable-experimental-feature CustomAvailability \
-// RUN:  -define-enabled-availability-domain EnabledDomain \
-// RUN:  -define-disabled-availability-domain DisabledDomain \
-// RUN:  -define-dynamic-availability-domain DynamicDomain
-
-// REQUIRES: swift_feature_CustomAvailability
-
-func alwaysAvailable() { }
-
-@available(EnabledDomain)
-func availableInEnabledDomain() { }
-
-@available(EnabledDomain, unavailable)
-func unavailableInEnabledDomain() { } // expected-note * {{'unavailableInEnabledDomain()' has been explicitly marked unavailable here}}
-
-@available(DisabledDomain, unavailable)
-func unavailableInDisabledDomain() { } // expected-note * {{'unavailableInDisabledDomain()' has been explicitly marked unavailable here}}
-
-@available(DynamicDomain)
-func availableInDynamicDomain() { }
-
-@available(DynamicDomain, deprecated, message: "Use something else")
-func deprecatedInDynamicDomain() { }
-
-@available(DynamicDomain, unavailable)
-func unavailableInDynamicDomain() { } // expected-note * {{'unavailableInDynamicDomain()' has been explicitly marked unavailable here}}
-
-@available(UnknownDomain) // expected-warning {{unrecognized platform name 'UnknownDomain'}}
-func availableInUnknownDomain() { }
-
-func testDeployment() {
-  alwaysAvailable()
-  availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
-  unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-  unavailableInDisabledDomain() // expected-error {{'unavailableInDisabledDomain()' is unavailable}}
-  deprecatedInDynamicDomain() // expected-warning {{'deprecatedInDynamicDomain()' is deprecated: Use something else}}
-  unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
-  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-  availableInUnknownDomain()
-}
-
-func testIfAvailable(_ truthy: Bool) {
-  if #available(EnabledDomain) {
-    availableInEnabledDomain()
-    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-    availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-    unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
-
-    if #available(DynamicDomain) {
-      availableInEnabledDomain()
-      unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-      availableInDynamicDomain()
-      unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
-    } else {
-      availableInEnabledDomain()
-      unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-      availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-      unavailableInDynamicDomain()
-    }
-
-    if #unavailable(EnabledDomain) {
-      // Unreachable.
-      availableInEnabledDomain()
-      unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-      availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-      unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
-    }
-  } else {
-    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
-    unavailableInEnabledDomain()
-    availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-    unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
-  }
-
-  if #available(EnabledDomain), #available(DynamicDomain) {
-    availableInEnabledDomain()
-    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-    availableInDynamicDomain()
-    unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
-  } else {
-    // In this branch, we only know that one of the domains is unavailable,
-    // but we don't know which.
-    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
-    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-    availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-    unavailableInDynamicDomain() // expected-error {{'unavailableInDynamicDomain()' is unavailable}}
-  }
-
-  if #available(EnabledDomain), truthy {
-    availableInEnabledDomain()
-    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-  } else {
-    // In this branch, the state of EnabledDomain remains unknown since
-    // execution will reach here if "truthy" is false.
-    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
-    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-  }
-
-  if #unavailable(EnabledDomain) {
-    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
-    unavailableInEnabledDomain()
-  } else {
-    availableInEnabledDomain()
-    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-  }
-
-  // FIXME: [availability] Support mixed #available and #unavailable.
-  if #unavailable(EnabledDomain), #available(DynamicDomain) {
-    // expected-error@-1 {{#available and #unavailable cannot be in the same statement}}
-  }
-}
-
-func testWhileAvailable() {
-  while #available(EnabledDomain) {
-    availableInEnabledDomain()
-    unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-  }
-
-  while #unavailable(EnabledDomain) {
-    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
-    unavailableInEnabledDomain()
-  }
-}
-
-func testGuardAvailable() {
-  guard #available(EnabledDomain) else {
-    availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
-    unavailableInEnabledDomain()
-    availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-
-    return
-  }
-
-  availableInEnabledDomain()
-  unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-}
-
-@available(EnabledDomain)
-func testEnabledDomainAvailable() {
-  availableInEnabledDomain()
-  unavailableInEnabledDomain() // expected-error {{'unavailableInEnabledDomain()' is unavailable}}
-
-  if #available(EnabledDomain) {} // FIXME: [availability] Diagnose as redundant
-  if #unavailable(EnabledDomain) {} // FIXME: [availability] Diagnose as unreachable
-
-  alwaysAvailable()
-  unavailableInDisabledDomain() // expected-error {{'unavailableInDisabledDomain()' is unavailable}}
-  deprecatedInDynamicDomain() // expected-warning {{'deprecatedInDynamicDomain()' is deprecated: Use something else}}
-  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-  availableInUnknownDomain()
-}
-
-@available(EnabledDomain, unavailable)
-func testEnabledDomainUnavailable() {
-  availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
-  unavailableInEnabledDomain()
-
-  if #available(EnabledDomain) {} // FIXME: [availability] Diagnose as unreachable
-  if #unavailable(EnabledDomain) {} // FIXME: [availability] Diagnose as redundant
-
-  alwaysAvailable()
-  unavailableInDisabledDomain() // expected-error {{'unavailableInDisabledDomain()' is unavailable}}
-  deprecatedInDynamicDomain() // expected-warning {{'deprecatedInDynamicDomain()' is deprecated: Use something else}}
-  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-  availableInUnknownDomain()
-}
-
-@available(*, unavailable)
-func testUniversallyUnavailable() {
-  alwaysAvailable()
-  // FIXME: [availability] Diagnostic consistency: potentially unavailable declaration shouldn't be diagnosed
-  // in contexts that are unavailable to broader domains
-  availableInEnabledDomain() // expected-error {{'availableInEnabledDomain()' is only available in EnabledDomain}}
-  unavailableInDisabledDomain()
-  deprecatedInDynamicDomain() // expected-warning {{'deprecatedInDynamicDomain()' is deprecated: Use something else}}
-  availableInDynamicDomain() // expected-error {{'availableInDynamicDomain()' is only available in DynamicDomain}}
-  availableInUnknownDomain()
-
-  if #available(EnabledDomain) {} // FIXME: [availability] Diagnose?
-  if #unavailable(EnabledDomain) {} // FIXME: [availability] Diagnose?
-}
-
-@available(EnabledDomain)
-struct EnabledDomainAvailable {
-  @available(DynamicDomain)
-  func dynamicDomainAvailableMethod() {
-    availableInEnabledDomain()
-    availableInDynamicDomain()
-
-    alwaysAvailable()
-    unavailableInDisabledDomain() // expected-error {{'unavailableInDisabledDomain()' is unavailable}}
-  }
-}
diff --git a/test/Sema/availability_isolated_any.swift b/test/Sema/availability_isolated_any.swift
deleted file mode 100644
index e2103145f88bd..0000000000000
--- a/test/Sema/availability_isolated_any.swift
+++ /dev/null
@@ -1,43 +0,0 @@
-// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx10.50
-
-// REQUIRES: OS=macosx
-
-// Concrete uses of @isolated(any) are fine.
-func expectIsolatedAny(fn: @isolated(any) () -> ()) {}
-
-func testConcrete1(fn: @isolated(any) () -> ()) {
-  expectIsolatedAny(fn: fn)
-}
-func testConcrete2(fn: @isolated(any) () -> ()) {
-  expectIsolatedAny {}
-}
-func testConcrete3(fn: @MainActor () -> ()) {
-  expectIsolatedAny {}
-}
-
-func testErasure(fn: @escaping @isolated(any) () -> ()) -> Any {
-  return fn // expected-error {{runtime support for @isolated(any) function types is only available in}}
-  // expected-note @-2 {{add @available attribute to enclosing global function}}
-  // expected-note @-2 {{add 'if #available' version check}}
-}
-
-func testCovariantErasure(fn: @escaping () -> @isolated(any) () -> Void) -> (() -> Any) {
-  return fn // expected-error {{runtime support for @isolated(any) function types is only available in}}
-  // expected-note @-2 {{add @available attribute to enclosing global function}}
-  // expected-note @-2 {{add 'if #available' version check}}
-}
-
-func testContravariantErasure(fn: @escaping (Any) -> Void) -> ((@escaping @isolated(any) () -> Void) -> Void) {
-  return fn // expected-error {{runtime support for @isolated(any) function types is only available in}}
-  // expected-note @-2 {{add @available attribute to enclosing global function}}
-  // expected-note @-2 {{add 'if #available' version check}}
-}
-
-protocol P {
-  associatedtype A
-}
-
-struct S: P { // expected-note {{add @available attribute to enclosing struct}}
-  typealias A = @isolated(any) () -> () // expected-error {{runtime support for @isolated(any) function types is only available in}}
-  // expected-note @-1 {{add @available attribute to enclosing type alias}}
-}
diff --git a/test/Sema/availability_versions_canonical_macos.swift b/test/Sema/availability_versions_canonical_macos.swift
deleted file mode 100644
index fb18d412aa22f..0000000000000
--- a/test/Sema/availability_versions_canonical_macos.swift
+++ /dev/null
@@ -1,14 +0,0 @@
-// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx10.15 -disable-objc-attr-requires-foundation-module
-
-// REQUIRES: OS=macosx
-
-func markUsed<T>(_ t: T) {}
-
-@available(OSX 10.16, *)
-func introducedOn10_16() { }
-
-func useUnderPoundAvailable() {
-  if #available(OSX 10.16, *) {
-    introducedOn10_16() // no-error
-  }
-}
diff --git a/test/Sema/availability_with_overloading.swift b/test/Sema/availability_with_overloading.swift
deleted file mode 100644
index 3f473a0553254..0000000000000
--- a/test/Sema/availability_with_overloading.swift
+++ /dev/null
@@ -1,40 +0,0 @@
-// RUN: %target-swift-frontend -emit-sil -verify %s | %FileCheck %s
-
-// REQUIRES: OS=macosx
-
-protocol View {}
-
-extension View {
-  @_disfavoredOverload
-  func frame(width: Double?, height: Double? = nil) {
-  }
-}
-
-@available(macOS 999, *)
-extension View {
-  func frame(width: Double?) {
-  }
-}
-
-func test_disfavored_vs_unavailable(_ view: View) {
-  view.frame(width: 100) // Ok
-  // CHECK: function_ref @$s29availability_with_overloading4ViewPAAE5frame5width6heightySdSg_AGtF
-}
-
-struct S {
-  func foo<T: StringProtocol>(_: T) {}
-  func bar(_: Int, _: Int = 0) {}
-}
-
-@available(macOS 999, *)
-extension S {
-  func foo(_: String) {}
-  func bar(_: Int) {}
-}
-
-func test_generic_vs_unavailable(_ s: S) {
-  s.foo("") // Ok (picks available generic overload)
-  // CHECK: function_ref @$s29availability_with_overloading1SV3fooyyxSyRzlF
-  s.bar(42) // Ok (picks overload with defaulted argument)
-  // CHECK: function_ref @$s29availability_with_overloading1SV3baryySi_SitF
-}
diff --git a/test/Sema/bitwise_copyable.swift b/test/Sema/bitwise_copyable.swift
index 80c1f20290f0d..4ef9b6712a53b 100644
--- a/test/Sema/bitwise_copyable.swift
+++ b/test/Sema/bitwise_copyable.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift                       \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated                       \
 // RUN:     -disable-availability-checking                   \
 // RUN:     -enable-experimental-feature Sensitive           \
 // RUN:     -enable-experimental-feature LifetimeDependence  \
@@ -97,7 +97,7 @@ struct S_Explicit_With_Metatype_Optional_AnyObject : BitwiseCopyable {
 }
 
 @sensitive
-struct S_Explicit_Sensitive : BitwiseCopyable { // expected-error {{a @sensitive type cannot conform to 'BitwiseCopyable'}}
+struct S_Explicit_Sensitive : BitwiseCopyable { // expected-error {{a '@sensitive' type cannot conform to 'BitwiseCopyable'}}
 }
 
 @sensitive
diff --git a/test/Sema/bitwise_copyable_2.swift b/test/Sema/bitwise_copyable_2.swift
index b380bc84ea8cb..5a8e3eb041f89 100644
--- a/test/Sema/bitwise_copyable_2.swift
+++ b/test/Sema/bitwise_copyable_2.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift                          \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated                          \
 // RUN:     -enable-builtin-module                              \
 // RUN:     -enable-experimental-feature LifetimeDependence     \
 // RUN:     -debug-diagnostic-names
diff --git a/test/Sema/bitwise_copyable_nonresilient.swift b/test/Sema/bitwise_copyable_nonresilient.swift
index 58cfcafa14e2e..db39a49a64e85 100644
--- a/test/Sema/bitwise_copyable_nonresilient.swift
+++ b/test/Sema/bitwise_copyable_nonresilient.swift
@@ -9,7 +9,7 @@
 
 // RUN: %target-swift-frontend                           \
 // RUN:     %t/Downstream.swift                          \
-// RUN:     -typecheck -verify                           \
+// RUN:     -typecheck -verify -verify-ignore-unrelated                           \
 // RUN:     -debug-diagnostic-names                      \
 // RUN:     -I %t
 
diff --git a/test/Sema/bitwise_copyable_resilience.swift b/test/Sema/bitwise_copyable_resilience.swift
index f8777dc6953b6..4f023350dd795 100644
--- a/test/Sema/bitwise_copyable_resilience.swift
+++ b/test/Sema/bitwise_copyable_resilience.swift
@@ -10,7 +10,7 @@
 
 // RUN: %target-swift-frontend                           \
 // RUN:     %t/Downstream.swift                          \
-// RUN:     -typecheck -verify                           \
+// RUN:     -typecheck -verify -verify-ignore-unrelated                           \
 // RUN:     -debug-diagnostic-names                      \
 // RUN:     -I %t
 
diff --git a/test/Sema/borrow_and_mutate_accessors.swift b/test/Sema/borrow_and_mutate_accessors.swift
new file mode 100644
index 0000000000000..2e22978fc22ce
--- /dev/null
+++ b/test/Sema/borrow_and_mutate_accessors.swift
@@ -0,0 +1,41 @@
+// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature BorrowAndMutateAccessors -enable-experimental-feature CoroutineAccessors
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+// REQUIRES: swift_feature_CoroutineAccessors
+
+class Klass {
+  var _i: Int = 0
+}
+
+struct Struct {
+  var _i: Int = 0
+}
+
+extension Klass {
+  var i: Int {
+    borrow { // expected-error{{a borrow accessor is supported only on a struct or enum}}
+      return 0
+    }
+    mutate { // expected-error{{a mutate accessor is supported only on a struct or enum}}
+      return &_i
+    }
+  }
+}
+
+extension Struct {
+  var i: Int {
+    borrow {
+      return 0
+    }
+    mutate {
+      return &_i
+    }
+  }
+}
+
+// TODO: borrow and mutate protocol requirements
+protocol P {
+  var name: String { borrow } // expected-error{{property in protocol must have explicit { get } or { get set } specifier}} // expected-error{{expected get, read, or set in a protocol property}}
+  var phone: String { mutate } // expected-error{{property in protocol must have explicit { get } or { get set } specifier}} // expected-error{{expected get, read, or set in a protocol property}}
+}
+
diff --git a/test/Sema/clang_fn_type_mismatch.swift b/test/Sema/clang_fn_type_mismatch.swift
index 4f5f3fd0c4883..796fc17f1bef5 100644
--- a/test/Sema/clang_fn_type_mismatch.swift
+++ b/test/Sema/clang_fn_type_mismatch.swift
@@ -12,10 +12,12 @@ let _ : @convention(c) (Int) -> Int = f1!
 // expected-error@-1{{cannot convert value of type '@convention(c, cType: "size_t (*)(size_t)") (Int) -> Int' to specified type '@convention(c) (Int) -> Int'}}
 
 let _ : (@convention(c) (Int) -> Int)? = f1
-// expected-error@-1{{cannot convert value of type '(@convention(c, cType: "size_t (*)(size_t)") (Int) -> Int)?' to specified type '(@convention(c) (Int) -> Int)?'}}
+// expected-error@-1{{cannot assign value of type '(@convention(c, cType: "size_t (*)(size_t)") (Int) -> Int)?' to type '(@convention(c) (Int) -> Int)?'}}
+// expected-note@-2 {{arguments to generic parameter 'Wrapped' ('@convention(c, cType: "size_t (*)(size_t)") (Int) -> Int' and '@convention(c) (Int) -> Int') are expected to be equal}}
 
 let _ : (@convention(c, cType: "void *(*)(void *)") (Int) -> Int)? = f1
-// expected-error@-1{{cannot convert value of type '(@convention(c, cType: "size_t (*)(size_t)") (Int) -> Int)?' to specified type '(@convention(c, cType: "void *(*)(void *)") (Int) -> Int)?'}}
+// expected-error@-1{{cannot assign value of type '(@convention(c, cType: "size_t (*)(size_t)") (Int) -> Int)?' to type '(@convention(c, cType: "void *(*)(void *)") (Int) -> Int)?'}}
+// expected-note@-2 {{arguments to generic parameter 'Wrapped' ('@convention(c, cType: "size_t (*)(size_t)") (Int) -> Int' and '@convention(c, cType: "void *(*)(void *)") (Int) -> Int') are expected to be equal}}
 
 
 // Converting from @convention(c) -> @convention(swift) works
diff --git a/test/Sema/classes_equatable_hashable.swift b/test/Sema/classes_equatable_hashable.swift
index 37de0c7691b01..17005e704bb3e 100644
--- a/test/Sema/classes_equatable_hashable.swift
+++ b/test/Sema/classes_equatable_hashable.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -primary-file %s
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -primary-file %s
 
 class Foo: Equatable {} 
 // expected-error@-1 {{type 'Foo' does not conform to protocol 'Equatable'}} 
diff --git a/test/Sema/conformance_availability_implied.swift b/test/Sema/conformance_availability_implied.swift
new file mode 100644
index 0000000000000..789f5b785d131
--- /dev/null
+++ b/test/Sema/conformance_availability_implied.swift
@@ -0,0 +1,68 @@
+// RUN: %target-typecheck-verify-swift -swift-version 6
+// REQUIRES: OS=macosx
+
+// Protocols:
+
+protocol Base {
+  func f() // expected-note {{protocol requirement here}}
+}
+
+func takesBase<T: Base>(_: T.Type) {}
+
+protocol Derived1: Base {}
+protocol Derived2: Base {}
+
+@_marker protocol MarkerBase {}
+
+func takesMarkerBase<T: MarkerBase>(_: T.Type) {}
+
+protocol MarkerDerived1: MarkerBase {}
+protocol MarkerDerived2: MarkerBase {}
+
+// Verify that the implied conformance is macOS 100:
+struct Conformer1 {}
+
+@available(macOS 100, *)
+extension Conformer1: Derived1 {
+  func f() {}  // okay!
+}
+
+@available(macOS 200, *)
+extension Conformer1: Derived2 {}
+
+takesBase(Conformer1.self)
+// expected-error@-1 {{conformance of 'Conformer1' to 'Base' is only available in macOS 100 or newer}}
+// expected-note@-2 {{add 'if #available' version check}}
+
+// No warning about redundant MarkerBase conformance (rdar://142873265):
+@available(macOS 100, *)
+extension Conformer1: MarkerDerived1 {}
+
+@available(macOS 200, *)
+extension Conformer1: MarkerDerived2 {}
+
+takesMarkerBase(Conformer1.self)
+// expected-error@-1 {{conformance of 'Conformer1' to 'MarkerBase' is only available in macOS 100 or newer}}
+// expected-note@-2 {{add 'if #available' version check}}
+
+// Bad availability on the Base.f() witness:
+struct Conformer2 {}
+
+@available(macOS 100, *)
+extension Conformer2: Derived1 {
+// expected-error@-1 {{protocol 'Base' requires 'f()' to be available in macOS 100 and newer}}
+}
+
+@available(macOS 200, *)
+extension Conformer2: Derived2 {
+  func f() {} // expected-note {{'f()' declared here}}
+}
+
+protocol P: MarkerBase {}
+
+struct Conformer3: P {}
+
+@available(*, unavailable)
+extension Conformer3: MarkerDerived1 {}
+
+takesMarkerBase(Conformer3.self)
diff --git a/test/Sema/conformance_availability_implied_multifile.swift b/test/Sema/conformance_availability_implied_multifile.swift
new file mode 100644
index 0000000000000..fccb6a9f94834
--- /dev/null
+++ b/test/Sema/conformance_availability_implied_multifile.swift
@@ -0,0 +1,48 @@
+// RUN: %target-swift-frontend -typecheck -verify %s %S/Inputs/conformance_availability_implied_other.swift -swift-version 6
+// RUN: %target-swift-frontend -typecheck -verify %S/Inputs/conformance_availability_implied_other.swift %s -swift-version 6
+// REQUIRES: OS=macosx
+
+protocol Base {
+  func f()
+}
+
+func takesBase<T: Base>(_: T.Type) {}
+
+protocol Derived1: Base {}
+protocol Derived2: Base {}
+
+// Verify that the implied conformance is macOS 100:
+struct Conformer1 {}
+
+@available(macOS 100, *)
+extension Conformer1: Derived1 {
+  func f() {}  // okay!
+}
+
+// Note that Conformer1: Derived2 is in the other file
+
+func check1() {
+// expected-note@-1 {{add '@available' attribute to enclosing global function}}
+  takesBase(Conformer1.self)
+  // expected-error@-1 {{conformance of 'Conformer1' to 'Base' is only available in macOS 100 or newer}}
+  // expected-note@-2 {{add 'if #available' version check}}
+}
+
+// Verify that the implied conformance is macOS 200:
+// FIXME: This appears to be unsound!
+struct Conformer2 {}
+
+@available(macOS 200, *)
+extension Conformer2: Derived2 {
+  func f() {}
+}
+
+// Note that Conformer2: Derived1 is in the other file
+
+func check2() {
+// expected-note@-1 {{add '@available' attribute to enclosing global function}}
+  takesBase(Conformer2.self)
+  // expected-error@-1 {{conformance of 'Conformer2' to 'Base' is only available in macOS 200 or newer}}
+  // expected-note@-2 {{add 'if #available' version check}}
+}
+
diff --git a/test/Sema/copyable_constraint_defaulting_with_same_type_constraints.swift b/test/Sema/copyable_constraint_defaulting_with_same_type_constraints.swift
new file mode 100644
index 0000000000000..70500917b2469
--- /dev/null
+++ b/test/Sema/copyable_constraint_defaulting_with_same_type_constraints.swift
@@ -0,0 +1,77 @@
+// RUN: %target-swift-frontend -typecheck -verify %s
+
+struct Bar: ~Copyable {}
+
+struct Foo<T: ~Copyable> {
+    func foo() -> T { fatalError() }
+}
+
+extension Foo where T == Bar {
+    func bar() -> Bar {
+        return foo()
+    }
+}
+
+struct Foo2<T: ~Copyable, U: ~Copyable> {
+    func foo1() -> T { fatalError() }
+    func foo2() -> U { fatalError() }
+}
+
+extension Foo2 where T == Bar, U == Bar {
+    func bar1_1() -> Bar {
+        return foo1()
+    }
+    func bar1_2() -> Bar {
+        return foo2()
+    }
+}
+
+extension Foo2 where T == U, U == Bar {
+    func bar2_1() -> Bar {
+        return foo1()
+    }
+    func bar2_2() -> Bar {
+        return foo2()
+    }
+}
+
+extension Foo2 where T == Bar, U == T {
+    func bar3_1() -> Bar {
+        return foo1()
+    }
+    func bar3_2() -> Bar {
+        return foo2()
+    }
+}
+
+func needsCopyable<T>(_: T) {}
+
+// T and U are still Copyable by default here, since the equivalence class of
+// the same-type-constrained parameters is entirely within the scope of the
+// extension, and there is no explicit suppression of the default.
+extension Foo2 where T == U {
+    func test(_ x: T) {
+        needsCopyable(x)
+    }
+}
+
+// Explicitly suppressing Copyable on one type parameter also prevents the other
+// parameters in the equivalence class from defaulting to Copyable.
+extension Foo2 where T == U, T: ~Copyable {
+    func bar4_1() -> T {
+        return foo1()
+    }
+    func bar4_2() -> T {
+        return foo2()
+    }
+}
+
+extension Foo2 where T == U, U: ~Copyable {
+    func bar5_1() -> T {
+        return foo1()
+    }
+    func bar5_2() -> T {
+        return foo2()
+    }
+}
+
diff --git a/test/Sema/diag_constantness_check_os_log.swift b/test/Sema/diag_constantness_check_os_log.swift
index 72594c3c13a8e..ca3db089a89a5 100644
--- a/test/Sema/diag_constantness_check_os_log.swift
+++ b/test/Sema/diag_constantness_check_os_log.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 5
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5
 
 // REQUIRES: VENDOR=apple
 
diff --git a/test/Sema/diag_constantness_check_os_log_swift6.swift b/test/Sema/diag_constantness_check_os_log_swift6.swift
new file mode 100644
index 0000000000000..bfff81526f33f
--- /dev/null
+++ b/test/Sema/diag_constantness_check_os_log_swift6.swift
@@ -0,0 +1,33 @@
+// RUN: %target-typecheck-verify-swift -swift-version 6
+
+// REQUIRES: VENDOR=apple
+// REQUIRES: concurrency
+
+import OSLogTestHelper
+
+class Log {
+  @_semantics("oslog.requires_constant_arguments")
+  func debug(_: OSLogMessage) {}
+}
+
+@_semantics("constant_evaluable")
+@_transparent
+public func __outputFormatter(_ key: String, fallback: OSLogMessage) -> OSLogMessage {
+    fallback
+}
+
+@MainActor
+@_semantics("constant_evaluable")
+@_transparent
+public func __isolatedOutputFormatter(_ key: String, fallback: OSLogMessage) -> OSLogMessage {
+    fallback
+}
+
+func test(log: Log) {
+  log.debug(__outputFormatter("1", fallback: "msg")) // Ok
+}
+
+@MainActor
+func isolatedTest(log: Log) {
+  log.debug(__isolatedOutputFormatter("1", fallback: "msg")) // Ok
+}
diff --git a/test/Sema/diag_erroneous_iuo.swift b/test/Sema/diag_erroneous_iuo.swift
index a1e44f17e4cde..5a066e0185a2f 100644
--- a/test/Sema/diag_erroneous_iuo.swift
+++ b/test/Sema/diag_erroneous_iuo.swift
@@ -1,5 +1,5 @@
-// RUN: %target-typecheck-verify-swift -swift-version 5 -verify-additional-prefix swift5-
-// RUN: %target-typecheck-verify-swift -swift-version 4 -verify-additional-prefix swift4-
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5 -verify-additional-prefix swift5-
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 4 -verify-additional-prefix swift4-
 
 // These are all legal uses of '!'.
 struct Fine {
diff --git a/test/Sema/diag_non_ephemeral.swift b/test/Sema/diag_non_ephemeral.swift
index 6b0ba868f73b0..addd8fa591c7b 100644
--- a/test/Sema/diag_non_ephemeral.swift
+++ b/test/Sema/diag_non_ephemeral.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend -emit-module -enable-library-evolution -parse-as-library -o %t -module-name=ModuleA %S/Inputs/diag_non_ephemeral_module1.swift
 // RUN: %target-swift-frontend -emit-module -enable-library-evolution -parse-as-library -o %t -module-name=ModuleB %S/Inputs/diag_non_ephemeral_module2.swift
 // RUN: cp %s %t/main.swift
-// RUN: %target-swift-frontend -typecheck -verify -enable-invalid-ephemeralness-as-error -I %t %t/main.swift %S/Inputs/diag_non_ephemeral_globals.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -enable-invalid-ephemeralness-as-error -I %t %t/main.swift %S/Inputs/diag_non_ephemeral_globals.swift
 
 import ModuleA
 import ModuleB
diff --git a/test/Sema/diag_non_ephemeral_warning.swift b/test/Sema/diag_non_ephemeral_warning.swift
index 1b426796ed538..6f79831722775 100644
--- a/test/Sema/diag_non_ephemeral_warning.swift
+++ b/test/Sema/diag_non_ephemeral_warning.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend -emit-module -enable-library-evolution -parse-as-library -o %t -module-name=ModuleA %S/Inputs/diag_non_ephemeral_module1.swift
 // RUN: %target-swift-frontend -emit-module -enable-library-evolution -parse-as-library -o %t -module-name=ModuleB %S/Inputs/diag_non_ephemeral_module2.swift
 // RUN: cp %s %t/main.swift
-// RUN: %target-swift-frontend -typecheck -verify -I %t %t/main.swift %S/Inputs/diag_non_ephemeral_globals.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t %t/main.swift %S/Inputs/diag_non_ephemeral_globals.swift
 
 import ModuleA
 import ModuleB
diff --git a/test/Sema/diag_typealias.swift b/test/Sema/diag_typealias.swift
index 0d966d51c3eb9..2d6b6c92d9727 100644
--- a/test/Sema/diag_typealias.swift
+++ b/test/Sema/diag_typealias.swift
@@ -2,4 +2,4 @@
 
 struct S {}
 
-typealias S = S // expected-error {{type alias 'S' references itself}} expected-note {{while resolving type 'S'}} expected-note {{through reference here}}
+typealias S = S // expected-error {{type alias 'S' references itself}} expected-note {{while resolving type 'S'}}
diff --git a/test/Sema/diag_unintended_optional_behavior.swift b/test/Sema/diag_unintended_optional_behavior.swift
index 36a84226064fd..79c8a71ecec98 100644
--- a/test/Sema/diag_unintended_optional_behavior.swift
+++ b/test/Sema/diag_unintended_optional_behavior.swift
@@ -196,21 +196,35 @@ extension DefaultStringInterpolation {
   }
 }
 
+/// A type that provides a custom `StringInterpolation` type.
+struct CustomInterpolation: ExpressibleByStringInterpolation {
+    struct StringInterpolation: StringInterpolationProtocol {
+        init(literalCapacity: Int, interpolationCount: Int) {}
+        mutating func appendLiteral(_ literal: String) {}
+        mutating func appendInterpolation<T>(_ interp: T) {}
+    }
+    init(stringInterpolation: StringInterpolation) {}
+    init(stringLiteral: String) {}
+}
+
 func warnOptionalInStringInterpolationSegment(_ o : Int?) {
   print("Always some, Always some, Always some: \(o)")
   // expected-warning@-1 {{string interpolation produces a debug description for an optional value; did you mean to make this explicit?}}
-  // expected-note@-2 {{use 'String(describing:)' to silence this warning}} {{51-51=String(describing: }} {{52-52=)}} 
+  // expected-note@-2 {{use a default value parameter to avoid this warning}} {{52-52=, default: <#default value#>}}
   // expected-note@-3 {{provide a default value to avoid this warning}} {{52-52= ?? <#default value#>}}
+  // expected-note@-4 {{use 'String(describing:)' to silence this warning}} {{51-51=String(describing: }} {{52-52=)}}
   var i: Int? = o
   print("Always some, Always some, Always some: \(i)")
   // expected-warning@-1 {{string interpolation produces a debug description for an optional value; did you mean to make this explicit?}}
-  // expected-note@-2 {{use 'String(describing:)' to silence this warning}} {{51-51=String(describing: }} {{52-52=)}}
+  // expected-note@-2 {{use a default value parameter to avoid this warning}} {{52-52=, default: <#default value#>}}
   // expected-note@-3 {{provide a default value to avoid this warning}} {{52-52= ?? <#default value#>}}
+  // expected-note@-4 {{use 'String(describing:)' to silence this warning}} {{51-51=String(describing: }} {{52-52=)}}
   i = nil
   print("Always some, Always some, Always some: \(o.map { $0 + 1 })")
   // expected-warning@-1 {{string interpolation produces a debug description for an optional value; did you mean to make this explicit?}}
-  // expected-note@-2 {{use 'String(describing:)' to silence this warning}} {{51-51=String(describing: }} {{67-67=)}} 
+  // expected-note@-2 {{use a default value parameter to avoid this warning}} {{67-67=, default: <#default value#>}}
   // expected-note@-3 {{provide a default value to avoid this warning}} {{67-67= ?? <#default value#>}}
+  // expected-note@-4 {{use 'String(describing:)' to silence this warning}} {{51-51=String(describing: }} {{67-67=)}}
 
   print("Always some, Always some, Always some: \(o as Int?)") // No warning
   print("Always some, Always some, Always some: \(o.debugDescription)") // No warning.
@@ -221,8 +235,24 @@ func warnOptionalInStringInterpolationSegment(_ o : Int?) {
   
   print("Always some, Always some, Always some: \(ooST)")
   // expected-warning@-1 {{string interpolation produces a debug description for an optional value; did you mean to make this explicit?}}
-  // expected-note@-2 {{use 'String(describing:)' to silence this warning}} {{51-51=String(describing: }} {{55-55=)}} 
-  // expected-note@-3 {{provide a default value to avoid this warning}} {{55-55= ?? <#default value#>}}  
+  // expected-note@-2 {{use a default value parameter to avoid this warning}} {{55-55=, default: <#default value#>}}
+  // expected-note@-3 {{provide a default value to avoid this warning}} {{55-55= ?? <#default value#>}}
+  // expected-note@-4 {{use 'String(describing:)' to silence this warning}} {{51-51=String(describing: }} {{55-55=)}}
+
+  // Don't provide a `\(_:default:)` fix-it for optional strings; the `??`
+  // operator is the recommended warning resolution.
+  let s: String? = o.map(String.init)
+  print("Always some, Always some, Always some: \(s)")
+  // expected-warning@-1 {{string interpolation produces a debug description for an optional value; did you mean to make this explicit?}}
+  // expected-note@-2 {{provide a default value to avoid this warning}} {{52-52= ?? <#default value#>}}
+  // expected-note@-3 {{use 'String(describing:)' to silence this warning}} {{51-51=String(describing: }} {{52-52=)}}
+  
+  // Don't provide a `\(_:default:)` fix-it for interpolations that don't resolve
+  // to strings.
+  let _: CustomInterpolation = "Always some, Always some, Always some: \(o)"
+  // expected-warning@-1 {{string interpolation produces a debug description for an optional value; did you mean to make this explicit?}}
+  // expected-note@-2 {{provide a default value to avoid this warning}} {{75-75= ?? <#default value#>}}
+  // expected-note@-3 {{use 'String(describing:)' to silence this warning}} {{74-74=String(describing: }} {{75-75=)}}
 }
 
 // Make sure we don't double diagnose
diff --git a/test/Sema/diag_unowned_immediate_deallocation.swift b/test/Sema/diag_unowned_immediate_deallocation.swift
index d0770630f5472..315a23c9e989c 100644
--- a/test/Sema/diag_unowned_immediate_deallocation.swift
+++ b/test/Sema/diag_unowned_immediate_deallocation.swift
@@ -1,4 +1,6 @@
-// RUN: %target-typecheck-verify-swift -module-name ModuleName
+// RUN: %target-typecheck-verify-swift -module-name ModuleName -enable-upcoming-feature ImmutableWeakCaptures
+
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 protocol ClassProtocol : class {
   init()
@@ -271,7 +273,7 @@ func testUnownedVariableBindingDiag() throws {
 }
 
 func testMultipleBindingDiag() {
-  weak var c1 = C(), c2: C? = C(), c3: C? = D()
+  weak let c1 = C(), c2: C? = C(), c3: C? = D()
   // expected-warning@-1 {{instance will be immediately deallocated because variable 'c1' is 'weak'}}
   // expected-note@-2 {{a strong reference is required to prevent the instance from being deallocated}}
   // expected-note@-3 {{'c1' declared here}}
@@ -297,7 +299,7 @@ func testMultipleBindingDiag() {
 }
 
 func testTupleAndParenBinding() throws {
-  weak var ((c1), c2, c3): (C?, C?, C?) = (C() as C, (D()), try D(throwing: ()))
+  weak let ((c1), c2, c3): (C?, C?, C?) = (C() as C, (D()), try D(throwing: ()))
   // expected-warning@-1 {{instance will be immediately deallocated because variable 'c1' is 'weak'}}
   // expected-note@-2 {{a strong reference is required to prevent the instance from being deallocated}}
   // expected-note@-3 {{'c1' declared here}}
@@ -323,11 +325,11 @@ func testTupleAndParenBinding() throws {
 }
 
 func testInitializationThroughClassArchetypeDiag<T : ClassProtocol>(_ t: T, _ p: ClassProtocol) throws {
-  weak var t1: T? = T() // expected-warning {{instance will be immediately deallocated because variable 't1' is 'weak'}}
+  weak let t1: T? = T() // expected-warning {{instance will be immediately deallocated because variable 't1' is 'weak'}}
   // expected-note@-1 {{a strong reference is required to prevent the instance from being deallocated}}
   // expected-note@-2 {{'t1' declared here}}
 
-  weak var t2: ClassProtocol? = T(failable: ()) // expected-warning {{instance will be immediately deallocated because variable 't2' is 'weak'}}
+  weak let t2: ClassProtocol? = T(failable: ()) // expected-warning {{instance will be immediately deallocated because variable 't2' is 'weak'}}
   // expected-note@-1 {{a strong reference is required to prevent the instance from being deallocated}}
   // expected-note@-2 {{'t2' declared here}}
 
@@ -342,7 +344,7 @@ func testInitializationThroughClassArchetypeDiag<T : ClassProtocol>(_ t: T, _ p:
   let optionalTType: T.Type? = T.self
   let optionalPType: ClassProtocol.Type? = type(of: p)
 
-  weak var t5 = optionalTType?.init(failable: ()) // expected-warning {{instance will be immediately deallocated because variable 't5' is 'weak'}}
+  weak let t5 = optionalTType?.init(failable: ()) // expected-warning {{instance will be immediately deallocated because variable 't5' is 'weak'}}
   // expected-note@-1 {{a strong reference is required to prevent the instance from being deallocated}}
   // expected-note@-2 {{'t5' declared here}}
 
@@ -404,12 +406,12 @@ class C1 {
 }
 
 func testInitializationThroughMetaclassDiag(_ t: C.Type) {
-  weak var c1: C? = t.init() // expected-warning {{instance will be immediately deallocated because variable 'c1' is 'weak'}}
+  weak let c1: C? = t.init() // expected-warning {{instance will be immediately deallocated because variable 'c1' is 'weak'}}
   // expected-note@-1 {{a strong reference is required to prevent the instance from being deallocated}}
   // expected-note@-2 {{'c1' declared here}}
 
   let optionalCType: C.Type? = t
-  weak var c2 = optionalCType?.init(failable: ()) // expected-warning {{instance will be immediately deallocated because variable 'c2' is 'weak'}}
+  weak let c2 = optionalCType?.init(failable: ()) // expected-warning {{instance will be immediately deallocated because variable 'c2' is 'weak'}}
   // expected-note@-1 {{a strong reference is required to prevent the instance from being deallocated}}
   // expected-note@-2 {{'c2' declared here}}
 
@@ -439,7 +441,7 @@ func testInitializationThroughTupleElementDiag() {
 class E<T> {}
 
 func testGenericWeakClassDiag() {
-  weak var e = E<String>()
+  weak let e = E<String>()
   // expected-warning@-1 {{instance will be immediately deallocated because variable 'e' is 'weak'}}
   // expected-note@-2 {{a strong reference is required to prevent the instance from being deallocated}}
   // expected-note@-3 {{'e' declared here}}
@@ -465,7 +467,7 @@ extension Optional {
 }
 
 func testDontDiagnoseOnUnrelatedInitializer() {
-  weak var c = C?(dontDiagnoseOnThis: ())
+  weak let c = C?(dontDiagnoseOnThis: ())
   unowned let c1 = C?(dontDiagnoseOnThis: ())!
   _ = c; _ = c1
 }
@@ -476,8 +478,8 @@ class F {
 }
 
 func testDontDiagnoseThroughMembers() {
-  weak var c1 = F().c
-  weak var c2 = F().makeC()
+  weak let c1 = F().c
+  weak let c2 = F().makeC()
   _ = c1; _ = c2
 }
 
@@ -488,7 +490,7 @@ func testDontDiagnoseOnStrongVariable() {
 }
 
 func testDontDiagnoseThroughImmediatelyEvaluatedClosure() {
-  weak var c1 = { C() }()
+  weak let c1 = { C() }()
   unowned let c2 = { C() }()
   _ = c1; _ = c2
 }
diff --git a/test/Sema/discard.swift b/test/Sema/discard.swift
index 62cc50ce9db53..6896b8732a09b 100644
--- a/test/Sema/discard.swift
+++ b/test/Sema/discard.swift
@@ -99,7 +99,7 @@ struct File: ~Copyable {
     discard (self) // expected-error {{cannot convert value of type 'File' to expected argument type 'Int'}}
 
     // FIXME: we should get an error about it being illegal to discard in a closure.
-    let _ = { // expected-error {{type of expression is ambiguous without a type annotation}}
+    let _ = { // expected-error {{failed to produce diagnostic for expression}}
       discard self
       return 0
     }()
diff --git a/test/Sema/editor_placeholders.swift b/test/Sema/editor_placeholders.swift
index cf14d23b74fd2..0ff89e8617620 100644
--- a/test/Sema/editor_placeholders.swift
+++ b/test/Sema/editor_placeholders.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 func foo(_ x: Int) -> Int {}
 func foo(_ x: Float) -> Float {}
@@ -27,6 +27,12 @@ f(<#T#> + 1) // expected-error{{editor placeholder in source file}}
 f(<#T##Int#>) // expected-error{{editor placeholder in source file}}
 f(<#T##String#>) // expected-error{{editor placeholder in source file}} expected-error{{cannot convert value of type 'String' to expected argument type 'Int'}}
 
+<#foo#>(x:)<Int>; // expected-error {{editor placeholder in source file}}
+
+// These are actually raw identifiers
+`<#foo#>` // expected-error {{cannot find '<#foo#>' in scope}}
+`<#foo#>`(x:)<Int>; // expected-error {{cannot find '<#foo#>(x:)' in scope}}
+
 for x in <#T#> { // expected-error{{editor placeholder in source file}} expected-error{{for-in loop requires '()' to conform to 'Sequence'}}
 
 }
diff --git a/test/Sema/enum_conformance_synthesis.swift b/test/Sema/enum_conformance_synthesis.swift
index 20f299fd62454..5bd2d939f1af4 100644
--- a/test/Sema/enum_conformance_synthesis.swift
+++ b/test/Sema/enum_conformance_synthesis.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -primary-file %s %S/Inputs/enum_conformance_synthesis_other.swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -primary-file %s %S/Inputs/enum_conformance_synthesis_other.swift -verify-ignore-unknown -swift-version 4
 
 var hasher = Hasher()
 
diff --git a/test/Sema/enum_equatable_conditional.swift b/test/Sema/enum_equatable_conditional.swift
index e562924498c55..8f91f2d26feb2 100644
--- a/test/Sema/enum_equatable_conditional.swift
+++ b/test/Sema/enum_equatable_conditional.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 4
 
 struct NotEquatable { }
 
diff --git a/test/Sema/enum_post_hoc_raw_representable_with_raw_type.swift b/test/Sema/enum_post_hoc_raw_representable_with_raw_type.swift
index f80ba947f7079..00bd708d42b18 100644
--- a/test/Sema/enum_post_hoc_raw_representable_with_raw_type.swift
+++ b/test/Sema/enum_post_hoc_raw_representable_with_raw_type.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -o %t/enum_with_raw_type.swiftmodule %S/Inputs/enum_with_raw_type.swift
-// RUN: %target-swift-frontend -I %t -typecheck -verify %s
+// RUN: %target-swift-frontend -I %t -typecheck -verify -verify-ignore-unrelated %s
 
 import enum_with_raw_type
 
diff --git a/test/Sema/enum_raw_representable.swift b/test/Sema/enum_raw_representable.swift
index 0250405fdb0f6..bf5d0b62a12e2 100644
--- a/test/Sema/enum_raw_representable.swift
+++ b/test/Sema/enum_raw_representable.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 enum Foo : Int {
   case a, b, c
diff --git a/test/Sema/enum_raw_representable_object_literals.swift b/test/Sema/enum_raw_representable_object_literals.swift
index f70bbcea068ce..88fd2c14bd878 100644
--- a/test/Sema/enum_raw_representable_object_literals.swift
+++ b/test/Sema/enum_raw_representable_object_literals.swift
@@ -13,7 +13,7 @@ enum Foo: FooLiteral { // expected-error {{raw type 'FooLiteral' is not expressi
   typealias RawValue = Never
   var rawValue: Never { fatalError() }
   init(rawValue: Never) { fatalError() }
-  case bar1 = #colorLiteral(red: 1, green: 0, blue: 0, alpha: 1)
-  case bar2 = #imageLiteral(resourceName: "hello.png")
-  case bar3 = #fileLiteral(resourceName: "what.txt")
+  case bar1 = #colorLiteral(red: 1, green: 0, blue: 0, alpha: 1) // expected-error {{raw value for enum case must be a literal}}
+  case bar2 = #imageLiteral(resourceName: "hello.png") // expected-error {{raw value for enum case must be a literal}}
+  case bar3 = #fileLiteral(resourceName: "what.txt") // expected-error {{raw value for enum case must be a literal}}
 }
diff --git a/test/Sema/escapable_substitution_lifetime_dependency.swift b/test/Sema/escapable_substitution_lifetime_dependency.swift
index a97cbe578ef8e..988fa4ba94a4b 100644
--- a/test/Sema/escapable_substitution_lifetime_dependency.swift
+++ b/test/Sema/escapable_substitution_lifetime_dependency.swift
@@ -1,8 +1,8 @@
-// RUN: %target-swift-frontend -enable-experimental-feature LifetimeDependence -emit-sil -verify %s
+// RUN: %target-swift-frontend -enable-experimental-feature Lifetimes -emit-sil -verify %s
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
-@lifetime(copy x)
+@_lifetime(copy x)
 func id<T: ~Escapable>(_ x: T) -> T {
     return x
 }
@@ -25,7 +25,7 @@ func doubleidGeneric<U>(_: U.Type) -> (U) -> U {
     return double(id)
 }
 
-@lifetime(x: copy y)
+@_lifetime(x: copy y)
 func overwrite<T: ~Escapable>(_ x: inout T, _ y: T) {
     x = y
 }
diff --git a/test/Sema/extension_retroactive_conformances.swift b/test/Sema/extension_retroactive_conformances.swift
index 4645cb8b734dd..cd2f3af72d977 100644
--- a/test/Sema/extension_retroactive_conformances.swift
+++ b/test/Sema/extension_retroactive_conformances.swift
@@ -9,6 +9,10 @@ public protocol SampleProtocol2 {}
 public protocol SampleProtocol1a: SampleProtocol1 {}
 public protocol SampleProtocol1b: SampleProtocol1 {}
 
+public protocol SampleProtocol3<A> {
+  associatedtype A
+}
+
 public struct Sample1 {}
 public struct Sample2 {}
 public struct Sample2a {}
@@ -20,11 +24,16 @@ public struct Sample3 {}
 public struct Sample4 {}
 public struct Sample5 {}
 public struct Sample6 {}
+public struct Sample7 {}
+public struct Sample8 {}
 
 public struct SampleAlreadyConforms: SampleProtocol1 {}
 
 public struct GenericSample1<T> {}
 
+public struct Sample9 {}
+public struct Sample10 {}
+
 #else
 
 import Library
@@ -83,15 +92,15 @@ protocol ClientProtocol {}
 // ok, conforming a type from another module to a protocol within this module is totally fine
 extension Sample1: ClientProtocol {}
 
-struct Sample7: @retroactive SampleProtocol1 {} // expected-error {{'retroactive' attribute only applies in inheritance clauses in extensions}}{{17-30=}}
+struct MySample7: @retroactive SampleProtocol1 {} // expected-error {{'@retroactive' only applies in inheritance clauses in extensions}}{{19-32=}}
 
-extension Sample7: @retroactive ClientProtocol {} // expected-warning {{'retroactive' attribute does not apply; 'Sample7' is declared in this module}}{{20-33=}}
+extension MySample7: @retroactive ClientProtocol {} // expected-warning {{'retroactive' attribute does not apply; 'MySample7' is declared in this module}}{{22-35=}}
 
 extension Int: @retroactive ClientProtocol {} // expected-warning {{'retroactive' attribute does not apply; 'ClientProtocol' is declared in this module}}{{16-29=}}
 
-func f(_ x: @retroactive Int) {} // expected-error {{'retroactive' attribute only applies in inheritance clauses in extensions}}
+func f(_ x: @retroactive Int) {} // expected-error {{'@retroactive' only applies in inheritance clauses in extensions}}
 
-var x: @retroactive Int { 0 } // expected-error {{'retroactive' attribute only applies in inheritance clauses in extensions}}
+var x: @retroactive Int { 0 } // expected-error {{'@retroactive' only applies in inheritance clauses in extensions}}
 
 #if os(macOS)
 
@@ -109,4 +118,17 @@ extension GenericSample1: SampleProtocol1 where T: SampleProtocol1 {}
 // expected-warning@-1 {{extension declares a conformance of imported type 'GenericSample1' to imported protocol 'SampleProtocol1'; this will not behave correctly if the owners of 'Library' introduce this conformance in the future}}
 // expected-note@-2 {{add '@retroactive' to silence this warning}}
 
-#endif
+// Don't forget about protocol compositions
+extension Sample7: SampleProtocol1 & SampleProtocol2 {}
+// expected-warning@-1 {{extension declares a conformance of imported type 'Sample7' to imported protocols 'SampleProtocol1', 'SampleProtocol2'; this will not behave correctly if the owners of 'Library' introduce this conformance in the future}}
+// expected-note@-2 {{add '@retroactive' to silence this warning}}
+
+extension Sample8: @retroactive SampleProtocol1 & SampleProtocol2 {}  // ok
+
+extension Sample9: SampleProtocol3<Int> {}
+// expected-warning@-1 {{extension declares a conformance of imported type 'Sample9' to imported protocol 'SampleProtocol3'; this will not behave correctly if the owners of 'Library' introduce this conformance in the future}}
+// expected-note@-2 {{add '@retroactive' to silence this warning}}
+
+extension Sample10: @retroactive SampleProtocol3<Int> {}
+
+#endif
\ No newline at end of file
diff --git a/test/Sema/fixits-derived-conformances.swift b/test/Sema/fixits-derived-conformances.swift
index 1a748b2949c55..5145287fddd68 100644
--- a/test/Sema/fixits-derived-conformances.swift
+++ b/test/Sema/fixits-derived-conformances.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -emit-module -emit-library -module-name Types %S/Inputs/fixits-derived-conformances-multifile.swift -o %t/%target-library-name(Types)
-// RUN: %target-typecheck-verify-swift %s -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated %s -I %t
 
 import Types
 
@@ -17,5 +17,5 @@ extension GenericStruct: @retroactive Equatable { }
 
 extension Enum: @retroactive CaseIterable { }
 // expected-error@-1 {{extension outside of file declaring enum 'Enum' prevents automatic synthesis of 'allCases' for protocol 'CaseIterable'}}
-// expected-note@-2 {{add stubs for conformance}}{{44-44=\n    public static var allCases: [Enum]\n}}
+// expected-note@-2 {{add stubs for conformance}}{{44-44=\n    public static let allCases: [Enum]\n}}
 
diff --git a/test/Sema/generic_specialization.swift b/test/Sema/generic_specialization.swift
index f62873aca5193..a58dc4cbcd281 100644
--- a/test/Sema/generic_specialization.swift
+++ b/test/Sema/generic_specialization.swift
@@ -71,3 +71,17 @@ do {
   // expected-swift5-warning@-1 {{cannot explicitly specialize initializer 'init(_:)'}}
   // expected-swift6-error@-2 {{cannot explicitly specialize initializer 'init(_:)'}}
 }
+
+do {
+  // expected-error@+1:13 {{cannot specialize non-generic type 'module<Swift>'}}{{none}}
+  func f(_: Swift<Int>) {}
+}
+
+func overloadedGenericFn<T, U>(_ x: T, _ y: U) {} // expected-note {{found this candidate}}
+func overloadedGenericFn<T, U>(_ x: T, _ y: U, z: Int = 0) {} // expected-note {{found this candidate}}
+
+// Make sure we don't crash.
+func testSpecializedOverloaded() {
+  struct S<T> {}
+  _ = overloadedGenericFn<S, S> // expected-error {{no exact matches}}
+}
diff --git a/test/Sema/has_symbol.swift b/test/Sema/has_symbol.swift
index 39f55b42f9907..5ba90e46409de 100644
--- a/test/Sema/has_symbol.swift
+++ b/test/Sema/has_symbol.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/has_symbol_helper.swiftmodule -parse-as-library %S/Inputs/has_symbol/has_symbol_helper.swift -enable-library-evolution
-// RUN: %target-typecheck-verify-swift -disable-availability-checking -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-availability-checking -I %t
 
 // UNSUPPORTED: OS=windows-msvc
 
diff --git a/test/Sema/immutability.swift b/test/Sema/immutability.swift
index e1125efb7dd93..bd01cb8889dc6 100644
--- a/test/Sema/immutability.swift
+++ b/test/Sema/immutability.swift
@@ -45,7 +45,13 @@ func passClosure() {
   }
 }
 
-
+// FIXME: No 'var x = x' fix-it.
+do {
+  func f(x: Int) {
+    x = 3 // expected-error@:5 {{cannot assign to value: 'x' is a 'let' constant}}{{none}}
+    x += 3 // expected-error@:7 {{left side of mutating operator isn't mutable: 'x' is a 'let' constant}}{{none}}
+  }
+}
 
 class FooClass {
   class let type_let = 5 // expected-error {{class stored properties not supported in classes}}
diff --git a/test/Sema/immutability_overload_async.swift b/test/Sema/immutability_overload_async.swift
index 959156ec13697..50093bbf363b5 100644
--- a/test/Sema/immutability_overload_async.swift
+++ b/test/Sema/immutability_overload_async.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend  -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify
 // RUN: %target-swift-frontend  -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=targeted
 // RUN: %target-swift-frontend  -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
-// RUN: %target-swift-frontend  -target %target-swift-5.1-abi-triple %s -emit-sil -o /dev/null -verify -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 protocol Iterator {
   associatedtype Failure: Error
diff --git a/test/Sema/impl_throw_objc.swift b/test/Sema/impl_throw_objc.swift
index 8297ca804c677..d730526a162ae 100644
--- a/test/Sema/impl_throw_objc.swift
+++ b/test/Sema/impl_throw_objc.swift
@@ -7,5 +7,5 @@ import Foundation
 }
 
 class ApplicationTracker: NSObject, Tracker {
-    func track(event: String) {} // expected-error {{satisfying a throwing @objc method with a non-throwing method is not supported}}
+    func track(event: String) {} // expected-error {{satisfying a throwing '@objc' method with a non-throwing method is not supported}}
 }
diff --git a/test/Sema/implementation-only-deprecated.swift b/test/Sema/implementation-only-deprecated.swift
index e60d58c3eef8f..6fe92f81f1387 100644
--- a/test/Sema/implementation-only-deprecated.swift
+++ b/test/Sema/implementation-only-deprecated.swift
@@ -11,6 +11,12 @@
 // RUN:   -enable-library-evolution -swift-version 5 \
 // RUN:   -enable-upcoming-feature InternalImportsByDefault \
 // RUN:   -verify
+// RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
+// RUN:   -enable-library-evolution -swift-version 5 \
+// RUN:   -enable-upcoming-feature InternalImportsByDefault \
+// RUN:   -warnings-as-errors -Wwarning ImplementationOnlyDeprecated \
+// RUN:   -verify
+
 
 // REQUIRES: swift_feature_InternalImportsByDefault
 
diff --git a/test/Sema/implementation-only-import-from-non-resilient.swift b/test/Sema/implementation-only-import-from-non-resilient.swift
index e8561c6097592..9962eaa61be1d 100644
--- a/test/Sema/implementation-only-import-from-non-resilient.swift
+++ b/test/Sema/implementation-only-import-from-non-resilient.swift
@@ -9,6 +9,8 @@
 
 /// Build a client with and without library-evolution.
 // RUN: %target-swift-frontend -typecheck %t/client-non-resilient.swift -I %t -verify
+// RUN: %target-swift-frontend -typecheck %t/client-non-resilient.swift -I %t -verify \
+// RUN:   -warnings-as-errors -Wwarning ImplementationOnlyDeprecated
 // RUN: %target-swift-frontend -typecheck %t/client-resilient.swift -I %t -verify \
 // RUN:   -enable-library-evolution -swift-version 5
 
diff --git a/test/Sema/implementation-only-import-in-decls.swift b/test/Sema/implementation-only-import-in-decls.swift
index 03c62853fcac2..bc5508157311c 100644
--- a/test/Sema/implementation-only-import-in-decls.swift
+++ b/test/Sema/implementation-only-import-in-decls.swift
@@ -4,7 +4,7 @@
 // RUN: %target-swift-frontend -emit-module -o %t/BADLibrary.swiftmodule %S/Inputs/implementation-only-import-in-decls-helper.swift -I %t \
 // RUN:  -enable-library-evolution -swift-version 5
 
-// RUN: %target-typecheck-verify-swift -I %t \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t \
 // RUN:  -enable-library-evolution -swift-version 5
 
 import NormalLibrary
diff --git a/test/Sema/implementation-only-import-library-evolution.swift b/test/Sema/implementation-only-import-library-evolution.swift
index beca00620848f..24f63845f2f88 100644
--- a/test/Sema/implementation-only-import-library-evolution.swift
+++ b/test/Sema/implementation-only-import-library-evolution.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend -emit-module -o %t/NormalLibrary.swiftmodule %S/Inputs/implementation-only-import-in-decls-public-helper.swift
 // RUN: %target-swift-frontend -emit-module -o %t/BADLibrary.swiftmodule %S/Inputs/implementation-only-import-in-decls-helper.swift -I %t
 
-// RUN: %target-typecheck-verify-swift -I %t -enable-library-evolution
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t -enable-library-evolution
 
 @_implementationOnly import BADLibrary
 // expected-warning @-1 {{'@_implementationOnly' is deprecated, use 'internal import' instead}}
diff --git a/test/Sema/implementation-only-override.swift b/test/Sema/implementation-only-override.swift
index 7a32fb339b678..c74d66e0b46fd 100644
--- a/test/Sema/implementation-only-override.swift
+++ b/test/Sema/implementation-only-override.swift
@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-typecheck-verify-swift -I %S/Inputs/implementation-only-override -DERRORS -enable-library-evolution -enable-objc-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %S/Inputs/implementation-only-override -DERRORS -enable-library-evolution -enable-objc-interop
 
 // RUN: %target-swift-emit-module-interface(%t/Library.swiftinterface) %s -I %S/Inputs/implementation-only-override -enable-objc-interop
 // RUN: %target-swift-typecheck-module-from-interface(%t/Library.swiftinterface) -I %S/Inputs/implementation-only-override
diff --git a/test/Sema/implicit_lifetime_dependence.swift b/test/Sema/implicit_lifetime_dependence.swift
index 6b3617a1f724f..710fe47c312f0 100644
--- a/test/Sema/implicit_lifetime_dependence.swift
+++ b/test/Sema/implicit_lifetime_dependence.swift
@@ -1,11 +1,11 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature LifetimeDependence
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature Lifetimes
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct BufferView : ~Escapable, ~Copyable {
   let ptr: UnsafeRawBufferPointer?
   let c: Int
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   init(_ ptr: UnsafeRawBufferPointer?, _ c: Int) {
     self.ptr = ptr
     self.c = c
@@ -26,7 +26,7 @@ struct ImplicitInit3 : ~Escapable, ~Copyable {
 }
 
 func foo1() -> BufferView { // expected-error{{a function with a ~Escapable result needs a parameter to depend on}}
-  // expected-note@-1{{'@lifetime(immortal)' can be used to indicate that values produced by this initializer have no lifetime dependencies}}
+  // expected-note@-1{{'@_lifetime(immortal)' can be used to indicate that values produced by this initializer have no lifetime dependencies}}
   return BufferView(nil, 0)
 }
 
diff --git a/test/Sema/inline_always.swift b/test/Sema/inline_always.swift
new file mode 100644
index 0000000000000..bdda49b31f89e
--- /dev/null
+++ b/test/Sema/inline_always.swift
@@ -0,0 +1,132 @@
+// RUN: %target-typecheck-verify-swift -package-name pkg -enable-experimental-feature InlineAlways
+
+// REQUIRES: swift_feature_InlineAlways
+
+@inline(always) // okay
+@inlinable
+public func publicInlinableFunc() {}
+
+@inline(always) // okay
+@_alwaysEmitIntoClient
+public func publicInlinableFunc2() {}
+
+@inline(always) // okay
+@inlinable
+package func packageInlinableFunc() {}
+
+@inline(always) // okay
+internal func internalFunc() {}
+
+@usableFromInline
+internal func internalFuncUFI() {}
+
+@inline(always) // okay
+@inlinable
+func internalInlinable() {}
+
+@inline(always) // okay
+private func privateFunc() {}
+
+@inline(always) // okay
+fileprivate func filePrivateFunc() {}
+
+@inline(always) // okay, implies @inlinable
+public func publicFunc() {
+  internalFuncUFI() // okay because useableFromInline
+}
+
+func internalFunc2() {} //expected-note{{global function 'internalFunc2()' is not '@usableFromInline' or public}}
+
+@inline(always) // implies @inlinable
+public func publicFuncUsingInternal() {
+  internalFunc2() //expected-error{{global function 'internalFunc2()' is internal and cannot be referenced from an '@inlinable' function}}
+}
+
+func internalFunc3() {} //expected-note{{global function 'internalFunc3()' is not '@usableFromInline' or public}}
+
+@inline(always) // implies @inlinable
+package func packageFuncUsingInternal() {
+  internalFunc3() //expected-error{{global function 'internalFunc3()' is internal and cannot be referenced from an '@inlinable' function}}
+}
+
+@inline(always)
+func internalUsingInternal() {
+  internalFunc2()
+}
+
+@inline(always) // okay
+package func packageFunc() {}
+
+@inline(always) // expected-error{{cannot use '@inline(always)' together with '@usableFromInline'}}
+@usableFromInline
+func internalUFI() {}
+
+func internalFunc4() {} //expected-note{{global function 'internalFunc4()' is not '@usableFromInline' or public}}
+
+@inline(always)
+public var x: Int {
+   get {
+       internalFunc4() // expected-error{{global function 'internalFunc4()' is internal and cannot be referenced from an '@inlinable' function}}
+       return 1
+   }
+}
+
+class C {
+  static func staticMethodInA() {} // okay
+
+  @inline(always)
+  final func myMethod() {} // okay
+
+  @inline(always) // expected-error {{'@inline(always)' on class methods requires 'myMethod2()' to be marked 'final'}}
+  func myMethod2() {}
+
+  @inline(always)
+  final var myVarFinal : Int { // okay
+    return 0
+  }
+
+  @inline(always) // expected-error {{'@inline(always)' on class vars requires 'myVar' to be marked 'final'}}
+  var myVar : Int {
+    return 0
+  }
+
+  @inline(always)
+  final var myVar2Final: Int { // okay
+    get {
+      return 1
+    }
+  }
+
+  @inline(always) // expected-error {{'@inline(always)' on class vars requires 'myVar2' to be marked 'final'}}
+  var myVar2: Int {
+    get {
+      return 1
+    }
+  }
+
+  final var myVar3Final : Int { // okay
+    @inline(always)
+    get {
+      return 1
+    }
+  }
+
+
+  var myVar3: Int {
+    @inline(always) // expected-error {{'@inline(always)' on class variable accessors whose variable declaration is not final are not allowed}}
+    get {
+      return 1
+    }
+  }
+
+  @inline(always)
+  static func myMethod3() {} // okay
+}
+
+extension C {
+  @inline(always)
+  final func myMethod10() {} // okay
+
+  @inline(always)
+  func myMethod11() {} // okay
+}
diff --git a/test/Sema/inline_array_availability.swift b/test/Sema/inline_array_availability.swift
deleted file mode 100644
index 5ab09c4a6e97a..0000000000000
--- a/test/Sema/inline_array_availability.swift
+++ /dev/null
@@ -1,18 +0,0 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature InlineArrayTypeSugar -target %target-cpu-apple-macosx15.0
-
-// REQUIRES: swift_feature_InlineArrayTypeSugar
-// REQUIRES: OS=macosx
-
-func foo(x: InlineArray<3, Int>) {}
-// expected-error@-1 {{'InlineArray' is only available in}}
-// expected-note@-2 {{add @available attribute to enclosing global function}}
-
-func bar(x: [3 x Int]) {}
-// expected-error@-1 {{'InlineArray' is only available in}}
-// expected-note@-2 {{add @available attribute to enclosing global function}}
-
-@available(SwiftStdlib 9999, *)
-func baz(x: InlineArray<3, Int>) {}
-
-@available(SwiftStdlib 9999, *)
-func qux(x: [3 x Int]) {}
diff --git a/test/Sema/inlinearray.swift b/test/Sema/inlinearray.swift
index 19d766440224a..155cbc484c2eb 100644
--- a/test/Sema/inlinearray.swift
+++ b/test/Sema/inlinearray.swift
@@ -1,6 +1,4 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature InlineArrayTypeSugar
-
-// REQUIRES: swift_feature_InlineArrayTypeSugar
+// RUN: %target-typecheck-verify-swift -disable-availability-checking
 
 let a: InlineArray = [1, 2, 3] // Ok, InlineArray<3, Int>
 let b: InlineArray<_, Int> = [1, 2, 3] // Ok, InlineArray<3, Int>
@@ -13,26 +11,26 @@ let f: InlineArray<_, Int> = ["hello"] // expected-error {{cannot convert value
 
 let g: InlineArray<1, 1> // expected-error {{cannot use value type '1' for generic argument 'Element'}}
 
-let _: [3 x Int] = [1, 2, 3]  // Ok, InlineArray<3, Int>
-let _: [_ x Int] = [1, 2, 3]  // Ok, InlineArray<3, Int>
-let _: [3 x _] = [1, 2, 3]    // Ok, InlineArray<3, Int>
-let _: [_ x _] = ["", "", ""] // Ok, InlineArray<3, String>
+let _: [3 of Int] = [1, 2, 3]  // Ok, InlineArray<3, Int>
+let _: [_ of Int] = [1, 2, 3]  // Ok, InlineArray<3, Int>
+let _: [3 of _] = [1, 2, 3]    // Ok, InlineArray<3, Int>
+let _: [_ of _] = ["", "", ""] // Ok, InlineArray<3, String>
 
-let _: [3 x [3 x Int]] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
-let _: [3 x [3 x Int]] = [[1, 2], [3, 4, 5, 6]]
+let _: [3 of [3 of Int]] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
+let _: [3 of [3 of Int]] = [[1, 2], [3, 4, 5, 6]]
 // expected-error@-1 {{'3' elements in inline array literal, but got '2'}}
-// expected-error@-2 2{{cannot convert value of type '[Int]' to expected element type '[3 x Int]'}}
+// expected-error@-2 2{{cannot convert value of type '[Int]' to expected element type '[3 of Int]'}}
 
-let _ = [3 x [3 x Int]](repeating: [1, 2]) // expected-error {{expected '3' elements in inline array literal, but got '2'}}
-let _ = [3 x [_ x Int]](repeating: [1, 2])
+let _ = [3 of [3 of Int]](repeating: [1, 2]) // expected-error {{expected '3' elements in inline array literal, but got '2'}}
+let _ = [3 of [_ of Int]](repeating: [1, 2])
 
-let _: [Int x 10] = [1, 2] // expected-error {{element count must precede inline array element type}} {{15-17=Int}} {{9-12=10}}
+let _: [Int of 10] = [1, 2] // expected-error {{element count must precede inline array element type}} {{16-18=Int}} {{9-12=10}}
 // expected-error@-1 {{expected '10' elements in inline array literal, but got '2'}}
 
-let _: [4 x _] = [1, 2, 3]   // expected-error {{expected '4' elements in inline array literal, but got '3'}}
-let _: [3 x Int] = [1, 2, 3, 4] // expected-error {{expected '3' elements in inline array literal, but got '4'}}
-let _: [3 x String] = [1, 2, 3] // expected-error 3{{cannot convert value of type 'Int' to expected element type 'String'}}
-let _: [3 x String] = [1] // expected-error {{cannot convert value of type 'Int' to expected element type 'String'}}
+let _: [4 of _] = [1, 2, 3]   // expected-error {{expected '4' elements in inline array literal, but got '3'}}
+let _: [3 of Int] = [1, 2, 3, 4] // expected-error {{expected '3' elements in inline array literal, but got '4'}}
+let _: [3 of String] = [1, 2, 3] // expected-error 3{{cannot convert value of type 'Int' to expected element type 'String'}}
+let _: [3 of String] = [1] // expected-error {{cannot convert value of type 'Int' to expected element type 'String'}}
 // expected-error@-1 {{expected '3' elements in inline array literal, but got '1'}}
 
 func takeVectorOf2<T>(_: InlineArray<2, T>) {}
@@ -63,10 +61,10 @@ takeVectorOf2Int(["hello", "world"]) // expected-error {{cannot convert value of
 
 takeVectorOf2Int(["hello", "world", "!"]) // expected-error {{cannot convert value of type '[String]' to expected argument type 'InlineArray<2, Int>'}}
 
-func takeSugarVectorOf2<T>(_: [2 x T], ty: T.Type = T.self) {}
+func takeSugarVectorOf2<T>(_: [2 of T], ty: T.Type = T.self) {}
 takeSugarVectorOf2([1, 2])
 takeSugarVectorOf2(["hello"]) // expected-error {{expected '2' elements in inline array literal, but got '1'}}
-takeSugarVectorOf2(["hello"], ty: Int.self) // expected-error {{cannot convert value of type '[String]' to expected argument type '[2 x Int]'}}
+takeSugarVectorOf2(["hello"], ty: Int.self) // expected-error {{cannot convert value of type '[String]' to expected argument type '[2 of Int]'}}
 takeSugarVectorOf2(["hello", "hi"], ty: Int.self) // expected-error 2{{cannot convert value of type 'String' to expected element type 'Int'}}
 
 
@@ -112,15 +110,15 @@ extension InlineArray where Element: ~Copyable {
   }
 }
 
-extension [3 x Int] { // expected-note 2{{where 'count' = '2'}} expected-note {{where 'Element' = 'String'}}
+extension [3 of Int] { // expected-note 2{{where 'count' = '2'}} expected-note {{where 'Element' = 'String'}}
   func methodOnSugar() {}
 }
 
 func testExtension(
-  _ a: [3 x Int],
+  _ a: [3 of Int],
   _ b: InlineArray<3, Int>,
-  _ c: [2 x Int],
-  _ d: [2 x String]
+  _ c: [2 of Int],
+  _ d: [2 of String]
 ) {
   a.enumerated { _, _ in }
   a.methodOnSugar()
@@ -133,23 +131,31 @@ func testExtension(
 }
 
 func redecl(_ x: InlineArray<2, Int>) {} // expected-note {{'redecl' previously declared here}}
-func redecl(_ x: [2 x Int]) {} // expected-error {{invalid redeclaration of 'redecl'}}
+func redecl(_ x: [2 of Int]) {} // expected-error {{invalid redeclaration of 'redecl'}}
 
 func noRedecl(_ x: InlineArray<2, Int>) {}
-func noRedecl(_ x: [3 x Int]) {}
-func noRedecl(_ x: [2 x String]) {}
-func noRedecl(_ x: [3 x String]) {}
+func noRedecl(_ x: [3 of Int]) {}
+func noRedecl(_ x: [2 of String]) {}
+func noRedecl(_ x: [3 of String]) {}
 
-func testMismatches(_ x: [3 x Int], _ y: InlineArray<3, Int>) {
+func testMismatches(_ x: [3 of Int], _ y: InlineArray<3, Int>) {
   let _: InlineArray<3, Int> = x
-  let _: InlineArray<4, Int> = x // expected-error {{cannot assign value of type '[3 x Int]' to type 'InlineArray<4, Int>'}}
+  let _: InlineArray<4, Int> = x // expected-error {{cannot assign value of type '[3 of Int]' to type 'InlineArray<4, Int>'}}
   // expected-note@-1 {{arguments to generic parameter 'count' ('3' and '4') are expected to be equal}}
-  let _: InlineArray<3, String> = x  // expected-error {{cannot assign value of type '[3 x Int]' to type 'InlineArray<3, String>'}}
+  let _: InlineArray<3, String> = x  // expected-error {{cannot assign value of type '[3 of Int]' to type 'InlineArray<3, String>'}}
   // expected-note@-1 {{arguments to generic parameter 'Element' ('Int' and 'String') are expected to be equal}}
 
-  let _: [3 x Int] = y
-  let _: [4 x Int] = y // expected-error {{cannot assign value of type 'InlineArray<3, Int>' to type '[4 x Int]'}}
+  let _: [3 of Int] = y
+  let _: [4 of Int] = y // expected-error {{cannot assign value of type 'InlineArray<3, Int>' to type '[4 of Int]'}}
   // expected-note@-1 {{arguments to generic parameter 'count' ('3' and '4') are expected to be equal}}
-  let _: [3 x String] = y  // expected-error {{cannot assign value of type 'InlineArray<3, Int>' to type '[3 x String]'}}
+  let _: [3 of String] = y  // expected-error {{cannot assign value of type 'InlineArray<3, Int>' to type '[3 of String]'}}
   // expected-note@-1 {{arguments to generic parameter 'Element' ('Int' and 'String') are expected to be equal}}
 }
+
+func testPointerConversion() {
+  var inlineArray = InlineArray<1, Int>(repeating: 0)
+  acceptPointer(&inlineArray) // expected-error {{cannot convert value of type 'UnsafeMutablePointer<InlineArray<1, Int>>' to expected argument type 'UnsafeMutablePointer<Int>'}}
+                              // expected-note@-1 {{arguments to generic parameter 'Pointee' ('InlineArray<1, Int>' and 'Int') are expected to be equal}}
+}
+
+func acceptPointer(_ pointer: UnsafeMutablePointer<Int>) {}
diff --git a/test/Sema/integer_generics_spelling.swift b/test/Sema/integer_generics_spelling.swift
new file mode 100644
index 0000000000000..1379f0d2135dc
--- /dev/null
+++ b/test/Sema/integer_generics_spelling.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend -disable-availability-checking -typecheck -verify %s
+
+struct Foo<let n: Int> {}
+
+func foo(x: Foo<256>) {}
+
+func bar(x: Foo<0x100>) {
+    foo(x: x)
+}
+
+func oof(x: Foo<-256>) {}
+
+func rab(x: Foo<-0x100>) {
+    oof(x: x)
+}
diff --git a/test/Sema/issue-74858.swift b/test/Sema/issue-74858.swift
index 2c202b35ca1e1..1af06195f9c4b 100644
--- a/test/Sema/issue-74858.swift
+++ b/test/Sema/issue-74858.swift
@@ -4,6 +4,6 @@ typealias Alias<T> = Int
 
 func invalidSpecializeExpr(_ x: Alias<Int>.Type) {
   let y = x<Int>.self
-  // expected-error@-1 {{type of expression is ambiguous without a type annotation}}
+  // expected-error@-1 {{failed to produce diagnostic for expression}}
   // FIXME: Bad diagnostic
 }
diff --git a/test/Sema/keypaths_noncopyable.swift b/test/Sema/keypaths_noncopyable.swift
index 104bf1dbc23e2..82c802e562a6c 100644
--- a/test/Sema/keypaths_noncopyable.swift
+++ b/test/Sema/keypaths_noncopyable.swift
@@ -53,9 +53,9 @@ public func testKeypath<V: ~Copyable>(m: consuming M<V>) {
   // expected-error@-1 {{key path cannot refer to noncopyable type 'M<V>'}}
 
   let b = Box(NC())
-  _ = b.with(\.data)
-  _ = b.with(\.next)
-  _ = b.with(\.next?.wrapped) // expected-error {{key path cannot refer to noncopyable type 'NC'}}
+  _ = b.with(\.data) // expected-error {{key path cannot refer to noncopyable type 'NC'}}
+  _ = b.with(\.next) // expected-error {{key path cannot refer to noncopyable type 'NC'}}
+  _ = b.with(\.next?.wrapped) // expected-error 2 {{key path cannot refer to noncopyable type 'NC'}}
   _ = b.with(\.next!.wrapped.data) // expected-error {{key path cannot refer to noncopyable type 'NC'}}
 }
 
@@ -68,3 +68,16 @@ func testAsFunc(_ someA: A) -> Int {
   let fn: (A) -> Int = \A.b.c.d // expected-error {{key path cannot refer to noncopyable type 'B'}}
   return fn(someA)
 }
+
+// https://github.com/swiftlang/swift/issues/84150
+func testKeyPathToFunctionConversion() {
+  struct HasID: ~Copyable {
+    let id: Int
+  }
+
+  func map(_ operation: (consuming HasID) -> Int) {}
+
+  map(\.id) // expected-error {{key path cannot refer to noncopyable type 'HasID'}}
+
+  let _: (consuming HasID) -> Int = \.id // expected-error {{key path cannot refer to noncopyable type 'HasID'}}
+}
diff --git a/test/Sema/lifetime_attr.swift b/test/Sema/lifetime_attr.swift
index 4c31c7f6ec784..d0212792f106a 100644
--- a/test/Sema/lifetime_attr.swift
+++ b/test/Sema/lifetime_attr.swift
@@ -1,52 +1,87 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature LifetimeDependence
+// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature Lifetimes
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct NE : ~Escapable {
-  @lifetime(copy self) // expected-error{{invalid lifetime dependence specifier on non-existent self}}
+  @_lifetime(copy self) // expected-error{{invalid lifetime dependence specifier on non-existent self}}
   init() {}
 }
 
-@lifetime(copy nonexisting) // expected-error{{invalid parameter name specified 'nonexisting'}}
+@_lifetime(copy nonexisting) // expected-error{{invalid parameter name specified 'nonexisting'}}
 func invalidAttrOnNonExistingParam(_ ne: NE) -> NE {
   ne
 }
 
-@lifetime(copy self) // expected-error{{invalid lifetime dependence specifier on non-existent self}}
+@_lifetime(copy self) // expected-error{{invalid lifetime dependence specifier on non-existent self}}
 func invalidAttrOnNonExistingSelf(_ ne: NE) -> NE {
   ne
 }
 
-@lifetime(2) // expected-error{{invalid parameter index specified '2'}}
+@_lifetime(2) // expected-error{{invalid parameter index specified '2'}}
 func invalidAttrOnNonExistingParamIndex(_ ne: NE) -> NE {
   ne
 }
 
-@lifetime(copy ne, borrow ne) // expected-error{{duplicate lifetime dependence specifier}}
+@_lifetime(copy ne, borrow ne) // expected-error{{duplicate lifetime dependence specifier}}
 func invalidDuplicateLifetimeDependence1(_ ne: borrowing NE) -> NE {
   ne
 }
 
 class Klass {}
 
-@lifetime(borrow x) // expected-error{{invalid use of borrow dependence with consuming ownership}}
-func invalidDependence(_ x: consuming Klass) -> NE {
+@_lifetime(borrow x) // expected-error{{invalid use of borrow dependence with consuming ownership}}
+func invalidDependenceConsumeKlass(_ x: consuming Klass) -> NE {
   NE()
 }
 
-@lifetime(result: copy source) 
-@lifetime(result: borrow source) // TODO: display error here
-func invalidTarget(_ result: inout NE, _ source: consuming NE) { // expected-error{{invalid duplicate target lifetime dependencies on function}}
+@_lifetime(&x) // expected-error{{invalid use of & dependence with borrowing ownership}}
+               // expected-note @-1{{use '@_lifetime(borrow x)' instead}}
+func invalidDependenceBorrowKlass(_ x: borrowing Klass) -> NE {
+  NE()
+}
+
+@_lifetime(borrow x) // expected-error{{invalid use of borrow dependence with inout ownership}}
+                     // expected-note @-1{{use '@_lifetime(&x)' instead}}
+func invalidDependenceInoutKlass(_ x: inout Klass) -> NE {
+  NE()
+}
+
+@_lifetime(borrow x) // OK
+func invalidDependenceConsumeInt(_ x: consuming Int) -> NE {
+  NE()
+}
+
+@_lifetime(&x) // expected-error{{invalid use of & dependence with borrowing ownership}}
+               // expected-note @-1{{use '@_lifetime(borrow x)' instead}}
+func invalidDependenceBorrowInt(_ x: borrowing Int) -> NE {
+  NE()
+}
+
+@_lifetime(borrow x) // expected-error{{invalid use of borrow dependence with inout ownership}}
+                     // expected-note @-1{{use '@_lifetime(&x)' instead}}
+func invalidDependenceInoutInt(_ x: inout Int) -> NE {
+  NE()
+}
+
+@_lifetime(result: copy source1) // expected-error{{invalid duplicate target lifetime dependencies on function}}
+@_lifetime(result: copy source2)
+func invalidTarget(_ result: inout NE, _ source1: consuming NE, _ source2: consuming NE) {
+  result = source1
+}
+
+@_lifetime(result: copy source)   // expected-error{{invalid duplicate target lifetime dependencies on function}}
+@_lifetime(result: borrow source)
+func invalidSource(_ result: inout NE, _ source: consuming NE) {
   result = source
 }
 
-@lifetime(immortal)
+@_lifetime(immortal)
 func immortalConflict(_ immortal: Int) -> NE { // expected-error{{conflict between the parameter name and 'immortal' contextual keyword}}
   NE()
 }
 
 do {
-  struct Test: ~Escapable {
+  struct Test: ~Escapable { // expected-error{{cannot infer implicit initialization lifetime. Add an initializer with '@_lifetime(...)' for each parameter the result depends on}}
     var v1: Int
     var v2: NE
   }
@@ -61,5 +96,86 @@ do {
 }
 
 // rdar://146401190 ([nonescapable] implement non-inout parameter dependencies)
-@lifetime(span: borrow holder)
-func testParameterDep(holder: AnyObject, span: Span<Int>) {}  // expected-error{{lifetime-dependent parameter must be 'inout'}}
+@_lifetime(span: borrow holder)
+func testParameterDep(holder: AnyObject, span: Span<Int>) {}  // expected-error{{lifetime-dependent parameter 'span' must be 'inout'}}
+
+@_lifetime(&ne)
+func inoutLifetimeDependence(_ ne: inout NE) -> NE {
+  ne
+}
+
+@_lifetime(copy k) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(&k)' instead}}
+func dependOnEscapable(_ k: inout Klass) -> NE {
+  NE()
+}
+
+@_lifetime(copy k) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(borrow k)' instead}}
+func dependOnEscapable(_ k: borrowing Klass) -> NE { 
+  NE()
+}
+
+@_lifetime(copy k) // expected-error{{invalid lifetime dependence on an Escapable value with consuming ownership}}
+func dependOnEscapable(_ k: consuming Klass) -> NE { 
+  NE()
+}
+
+struct Wrapper : ~Escapable {
+  var _ne: NE
+
+  var ne: NE {
+    @_lifetime(copy self)
+    get {
+      _ne
+    }
+    @_lifetime(self: &self)
+    nonmutating _modify {// expected-error{{lifetime-dependent parameter 'self' must be 'inout'}}
+      // expected-error@-1{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
+    }
+  }
+
+  var otherNE: NE {
+    @_lifetime(copy self)
+    get {
+      _ne
+    }
+    @_lifetime(self: borrow newValue)
+    set {
+      self._ne = newValue
+    }
+    @_lifetime(&self)
+    _modify {
+      yield &self._ne
+    }
+  }
+}
+
+@_lifetime(inValue) // expected-error{{invalid lifetime dependence on an Escapable result}}
+func getInt(_ inValue: Int) -> Int {
+  return inValue
+}
+
+@_lifetime(_outValue: borrow inValue) // expected-error{{invalid lifetime dependence on an Escapable target}}
+func getInt(_outValue: inout Int, _ inValue: Int)  {
+  _outValue = inValue
+}
+
+@_lifetime(inValue) // expected-error{{invalid lifetime dependence on an Escapable result}}
+func getGeneric<T>(_ inValue: T) -> T {
+  return inValue
+}
+
+@_lifetime(_outValue: borrow inValue) // expected-error{{invalid lifetime dependence on an Escapable target}}
+func getGeneric<T>(_outValue: inout T, _ inValue: T)  {
+  _outValue = inValue
+}
+
+@_lifetime(borrow inValue)
+func getGeneric<T : ~Escapable>(_ inValue: T) -> T {
+  return inValue
+}
+
+@_lifetime(_outValue: borrow inValue)
+func getGeneric<T : ~Escapable>(_outValue: inout T, _ inValue: T)  {
+  _outValue = inValue
+}
+
diff --git a/test/Sema/lifetime_attr_nofeature.swift b/test/Sema/lifetime_attr_nofeature.swift
index 65834cb459675..a86d46ec238b5 100644
--- a/test/Sema/lifetime_attr_nofeature.swift
+++ b/test/Sema/lifetime_attr_nofeature.swift
@@ -1,10 +1,15 @@
 // RUN: %target-typecheck-verify-swift -disable-availability-checking
 // REQUIRES: asserts
 
-struct NE : ~Escapable { // expected-error{{an implicit initializer with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'}}
+struct NE : ~Escapable { // expected-error{{an implicit initializer cannot return a ~Escapable result}}
 }
 
-@lifetime(copy ne) // expected-error{{'@lifetime' attribute is only valid when experimental feature LifetimeDependence is enabled}} expected-error{{expected declaration}}
-func derive(_ ne: NE) -> NE { // expected-error{{a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'}}
+@_lifetime(copy ne) // expected-error{{'@_lifetime' attribute is only valid when experimental feature Lifetimes is enabled}}
+func derive(_ ne: NE) -> NE { // expected-error{{a function cannot return a ~Escapable result}}
   ne
 }
+
+func f_inout_infer(a: inout MutableRawSpan) {} // DEFAULT OK
+
+func f_inout_no_infer(a: inout MutableRawSpan, b: RawSpan) {} // DEFAULT OK
+
diff --git a/test/Sema/lifetime_depend_infer.swift b/test/Sema/lifetime_depend_infer.swift
index 631242a0685e7..5b0865bbd2c9b 100644
--- a/test/Sema/lifetime_depend_infer.swift
+++ b/test/Sema/lifetime_depend_infer.swift
@@ -1,184 +1,356 @@
 // RUN: %target-typecheck-verify-swift \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
-// Coverage testing for LifetimeDependence inferrence logic. The tests are grouped according to the design of
-// LifetimeDependenceChecker.
+// Coverage testing for LifetimeDependence inferrence logic. The tests are sorted and grouped according to
+// docs/ReferenceGuides/LifetimeAnnotation.md. To find the cases that cover the default lifetime
+// rules described in the documentation, search for DEFAULT.
+//
+// Each default case is also defined in Sema/lifetime_depend_infer_defaults.swift to check that the function type has
+// the correct dependencies.
 
 class C {}
 
 struct NE: ~Escapable {}
 
 struct NEImmortal: ~Escapable {
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init() {}
 }
 
+struct MutNE: ~Copyable & ~Escapable {}
+
 // =============================================================================
-// Handle non-Escapable results with 'self'
+// Single parameter default rule for functions
 // =============================================================================
 
-struct NonEscapableSelf: ~Escapable {
-  func methodNoParam() -> NonEscapableSelf { self } // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+func noParam_NEResult() -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result needs a parameter to depend on}}
+// expected-note@-1{{'@_lifetime(immortal)' can be used to indicate that values produced by this initializer have no lifetime dependencies}}
+
+@_lifetime(immortal)
+func noParamImmortal_NEResult() -> NEImmortal { NEImmortal() } // OK
+
+/* DEFAULT: @_lifetime(borrow i) */
+func oneTrivialParam_NEResult(i: Int) -> NEImmortal { NEImmortal() }
+
+/* DEFAULT: @_lifetime(borrow c) */
+func oneParam_NEResult(c: C) -> NEImmortal { NEImmortal() }
+
+/* DEFAULT: @_lifetime(borrow c) */
+@_lifetime(c)
+func oneParamLifetime_NEResult(c: C) -> NEImmortal { NEImmortal() }
+
+/* DEFAULT: @_lifetime(borrow c) */
+func oneParamBorrow_NEResult(c: borrowing C) -> NEImmortal { NEImmortal() } // OK
+
+/* DEFAULT: @_lifetime(borrow c) */
+@_lifetime(c)
+func oneParamBorrowLifetime_NEResult(c: borrowing C) -> NEImmortal { NEImmortal() } // OK
+
+func oneParamConsume_NEResult(c: consuming C) -> NEImmortal { NEImmortal() } // expected-error{{cannot borrow the lifetime of 'c', which has consuming ownership on a function}}
+
+@_lifetime(c) // expected-error{{invalid lifetime dependence on an Escapable value with consuming ownership}}
+func oneParamConsumeLifetime_NEResult(c: consuming C) -> NEImmortal { NEImmortal() }
+
+/* DEFAULT: @_lifetime(&c) */
+func oneInoutParam_NEResult(c: inout C) -> NEImmortal { NEImmortal() } // OK
+
+/* DEFAULT: @_lifetime(&c) */
+@_lifetime(c)
+func oneParamInoutLifetime_NEResult(c: inout C) -> NEImmortal { NEImmortal() } // OK
+
+func twoParams_NEResult(c: C, _: Int) -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result requires '@_lifetime(...)'}}
+
+@_lifetime(c)
+func twoParamsLifetime_NEResult(c: C, _: Int) -> NEImmortal { NEImmortal() }
+
+func twoParamsConsume_NEResult(c: consuming C, _: Int) -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result requires '@_lifetime(...)'}}
+
+func twoParamsBorrow_NEResult(c: borrowing C, _: Int) -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result requires '@_lifetime(...)'}}
+
+func twoParamsInout_NEResult(c: inout C, _: Int) -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result requires '@_lifetime(...)'}}
+
+func neParam_NEResult(ne: NE) -> NE { ne } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
 
-  @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
-  func methodNoParamLifetime() -> NonEscapableSelf { self }
+@_lifetime(ne) // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
+func neParamLifetime_NEResult(ne: NE) -> NE { ne }
 
-  @lifetime(copy self) // OK
-  func methodNoParamCopy() -> NonEscapableSelf { self }
+func neParamBorrow_NEResult(ne: borrowing NE) -> NE { ne } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
 
-  @lifetime(borrow self) // OK
-  func methodNoParamBorrow() -> NonEscapableSelf { self }
+@_lifetime(ne) // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
+func neParamBorrowLifetime_NEResult(ne: borrowing NE) -> NE { ne }
 
-  mutating func mutatingMethodNoParam() -> NonEscapableSelf { self } // expected-error{{a mutating method with a ~Escapable result requires '@lifetime(...)'}}
- // expected-error@-1{{a mutating method with a ~Escapable 'self' requires '@lifetime(self: ...)'}}
+func neParamConsume_NEResult(ne: consuming NE) -> NE { ne } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
 
-  @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
-  mutating func mutatingMethodNoParamLifetime() -> NonEscapableSelf { self }
+@_lifetime(ne) // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
+func neParamConsumeLifetime_NEResult(ne: consuming NE) -> NE { ne }
 
-  @lifetime(copy self) // OK
-  mutating func mutatingMethodNoParamCopy() -> NonEscapableSelf { self }
+func neParam_IntParam_NEResult(ne: NE, _:Int) -> NE { ne } // expected-error{{a function with a ~Escapable result requires '@_lifetime(...)'}}
 
-  @lifetime(borrow self) // OK
-  mutating func mutatingMethodNoParamBorrow() -> NonEscapableSelf { self }
+func inoutParam_inoutParam_NEResult(a: inout C, b: inout C) -> NEImmortal { NEImmortal() }
+// expected-error@-1{{a function with a ~Escapable result requires '@_lifetime(...)'}}
 
-  func methodOneParam(_: Int) -> NonEscapableSelf { self } // expected-error{{a method with a ~Escapable result requires '@lifetime(...)'}}
 
-  @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
-  func methodOneParamLifetime(_: Int) -> NonEscapableSelf { self }
+// =============================================================================
+// Single parameter default rule for methods
+// =============================================================================
+
+struct EscapableNonTrivialSelf {
+  let c: C
+
+  init(c: C) { self.c = c }
+
+  /* DEFAULT: @_lifetime(borrow self) */
+  func noParam_NEResult() -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(borrow self) */
+  @_lifetime(self)
+  func noParamLifetime_NEResult() -> NEImmortal { NEImmortal() }
+
+  @_lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(borrow self)' instead}}
+  func noParamCopy_NEResult() -> NEImmortal { NEImmortal() }
 
-  @lifetime(copy self) // OK
-  func methodOneParamCopy(_: Int) -> NonEscapableSelf { self }
+  @_lifetime(borrow self)
+  func noParamBorrow_NEResult() -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self) // OK
-  func methodOneParamBorrow(_: Int) -> NonEscapableSelf { self }
+  /* DEFAULT: @_lifetime(&self) */
+  mutating func mutating_noParam_NEResult() -> NEImmortal { NEImmortal() }
 
-  mutating func mutatingMethodOneParam(_: Int) -> NonEscapableSelf { self } // expected-error{{a mutating method with a ~Escapable result requires '@lifetime(...)'}}
-  // expected-error@-1{{a mutating method with a ~Escapable 'self' requires '@lifetime(self: ...)'}}
+  /* DEFAULT: @_lifetime(&self) */
+  @_lifetime(self)
+  mutating func mutating_noParamLifetime_NEResult() -> NEImmortal { NEImmortal() }
 
-  @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
-  mutating func mutatingMethodOneParamLifetime(_: Int) -> NonEscapableSelf { self }
+  @_lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(&self)' instead}}
+  mutating func mutating_noParamCopy_NEResult() -> NEImmortal { NEImmortal() }
 
-  @lifetime(copy self) // OK
-  mutating func mutatingMethodOneParamCopy(_: Int) -> NonEscapableSelf { self }
+  @_lifetime(&self)
+  mutating func mutating_noParamBorrow_NEResult() -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self) // OK
-  mutating func mutatingMethodOneParamBorrow(_: Int) -> NonEscapableSelf { self }
+  func oneParam_NEResult(_: Int) -> NEImmortal { NEImmortal() } // expected-error{{a method with a ~Escapable result requires '@_lifetime(...)'}}
+
+  @_lifetime(self)
+  func oneParamLifetime_NEResult(_: Int) -> NEImmortal { NEImmortal() }
+
+  @_lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(borrow self)' instead}}
+  func oneParamCopy_NEResult(_: Int) -> NEImmortal { NEImmortal() }
+
+  @_lifetime(borrow self)
+  func oneParamBorrow_NEResult(_: Int) -> NEImmortal { NEImmortal() }
+
+  mutating func mutating_oneParam_NEResult(_: Int) -> NEImmortal { NEImmortal() } // expected-error{{a mutating method with a ~Escapable result requires '@_lifetime(...)'}}
+
+  /* DEFAULT: @_lifetime(borrow self) */
+  @_lifetime(self)
+  mutating func mutating_oneParamLifetime_NEResult(_: Int) -> NEImmortal { NEImmortal() }
+
+  @_lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(&self)' instead}}
+  mutating func mutating_oneParamCopy_NEResult(_: Int) -> NEImmortal { NEImmortal() }
+
+  @_lifetime(&self)
+  mutating func mutating_oneParamBorrow_NEResult(_: Int) -> NEImmortal { NEImmortal() }
 }
 
 struct EscapableTrivialSelf {
-  func methodNoParam() -> NEImmortal { NEImmortal() } // expected-error{{cannot infer lifetime dependence on a method because 'self' is BitwiseCopyable}}
+  func noParam_NEResult() -> NEImmortal { NEImmortal() } // expected-error{{cannot infer lifetime dependence on a method because 'self' is BitwiseCopyable}}
 
-  @lifetime(self) // OK
-  func methodNoParamLifetime() -> NEImmortal { NEImmortal() }
+  /* DEFAULT: @_lifetime(borrow self) */
+  @_lifetime(self) // OK
+  func noParamLifetime_NEResult() -> NEImmortal { NEImmortal() }
 
-  @lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@lifetime(borrow self)' instead}}
-  func methodNoParamCopy() -> NEImmortal { NEImmortal() }
+  @_lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(borrow self)' instead}}
+  func noParamCopy_NEResult() -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self) // OK
-  func methodNoParamBorrow() -> NEImmortal { NEImmortal() }
+  @_lifetime(borrow self) // OK
+  func noParamBorrow_NEResult() -> NEImmortal { NEImmortal() }
 
-  func mutatingMethodNoParam() -> NEImmortal { NEImmortal() } // expected-error{{cannot infer lifetime dependence on a method because 'self' is BitwiseCopyable}}
+  func mutatingMethodNoParam_NEResult() -> NEImmortal { NEImmortal() } // expected-error{{cannot infer lifetime dependence on a method because 'self' is BitwiseCopyable}}
 
-  @lifetime(self) // OK
-  mutating func mutatingMethodNoParamLifetime() -> NEImmortal { NEImmortal() }
+  /* DEFAULT: @_lifetime(borrow self) */
+  @_lifetime(self) // OK
+  mutating func mutatingMethodNoParamLifetime_NEResult() -> NEImmortal { NEImmortal() }
 
-  @lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@lifetime(borrow self)' instead}}
-  mutating func mutatingMethodNoParamCopy() -> NEImmortal { NEImmortal() }
+  @_lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(&self)' instead}}
+  mutating func mutatingMethodNoParamCopy_NEResult() -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self)
-  mutating func mutatingMethodNoParamBorrow() -> NEImmortal { NEImmortal() }
+  @_lifetime(&self)
+  mutating func mutatingMethodNoParamBorrow_NEResult() -> NEImmortal { NEImmortal() }
 
-  func methodOneParam(_: Int) -> NEImmortal { NEImmortal() } // expected-error{{a method with a ~Escapable result requires '@lifetime(...)'}}
+  func oneParam_NEResult_NEResult(_: Int) -> NEImmortal { NEImmortal() } // expected-error{{a method with a ~Escapable result requires '@_lifetime(...)'}}
 
-  @lifetime(self)
-  func methodOneParamLifetime(_: Int) -> NEImmortal { NEImmortal() }
+  /* DEFAULT: @_lifetime(borrow self) */
+  @_lifetime(self)
+  func oneParamLifetime_NEResult(_: Int) -> NEImmortal { NEImmortal() }
 
-  @lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@lifetime(borrow self)' instead}}
-  func methodOneParamCopy(_: Int) -> NEImmortal { NEImmortal() }
+  @_lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(borrow self)' instead}}
+  func oneParamCopy_NEResult(_: Int) -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self)
-  func methodOneParamBorrow(_: Int) -> NEImmortal { NEImmortal() }
+  @_lifetime(borrow self)
+  func oneParamBorrow_NEResult(_: Int) -> NEImmortal { NEImmortal() }
 
-  mutating func mutatingMethodOneParam(_: Int) -> NEImmortal { NEImmortal() } // expected-error{{a mutating method with a ~Escapable result requires '@lifetime(...)'}}
+  mutating func mutating_oneParam_NEResult(_: Int) -> NEImmortal { NEImmortal() } // expected-error{{a mutating method with a ~Escapable result requires '@_lifetime(...)'}}
 
-  @lifetime(self)
-  mutating func mutatingMethodOneParamLifetime(_: Int) -> NEImmortal { NEImmortal() }
+  /* DEFAULT: @_lifetime(borrow self) */
+  @_lifetime(self)
+  mutating func mutating_oneParamLifetime_NEResult(_: Int) -> NEImmortal { NEImmortal() }
 
-  @lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@lifetime(borrow self)' instead}}
-  mutating func mutatingMethodOneParamCopy(_: Int) -> NEImmortal { NEImmortal() }
+  @_lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@_lifetime(&self)' instead}}
+  mutating func mutating_oneParamCopy_NEResult(_: Int) -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self)
-  mutating func mutatingMethodOneParamBorrow(_: Int) -> NEImmortal { NEImmortal() }
+  @_lifetime(&self)
+  mutating func mutating_oneParamBorrow_NEResult(_: Int) -> NEImmortal { NEImmortal() }
 }
 
-struct EscapableNonTrivialSelf {
-  let c: C
+struct NonEscapableSelf: ~Escapable {
+  func noParam_NEResult() -> NonEscapableSelf { self } // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
 
-  init(c: C) { self.c = c }
+  @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
+  func noParamLifetime_NEResult() -> NonEscapableSelf { self }
+
+  @_lifetime(copy self) // OK
+  func noParamCopy_NEResult_NEResult() -> NonEscapableSelf { self }
+
+  @_lifetime(borrow self) // OK
+  func noParamBorrow_NEResult() -> NonEscapableSelf { self }
+
+  mutating func mutating_noParam_NEResult() -> NonEscapableSelf { self } // expected-error{{a mutating method with a ~Escapable result requires '@_lifetime(...)'}}
 
-  func methodNoParam() -> NEImmortal { NEImmortal() }
+  @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
+  mutating func mutating_noParamLifetime_NEResult() -> NonEscapableSelf { self }
 
-  @lifetime(self)
-  func methodNoParamLifetime() -> NEImmortal { NEImmortal() }
+  @_lifetime(copy self) // OK
+  mutating func mutating_noParamCopy_NEResult() -> NonEscapableSelf { self }
 
-  @lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@lifetime(borrow self)' instead}}
-  func methodNoParamCopy() -> NEImmortal { NEImmortal() }
+  @_lifetime(&self) // OK
+  mutating func mutating_noParamBorrow_NEResult() -> NonEscapableSelf { self }
 
-  @lifetime(borrow self)
-  func methodNoParamBorrow() -> NEImmortal { NEImmortal() }
+  func oneParam_NEResult(_: Int) -> NonEscapableSelf { self } // expected-error{{a method with a ~Escapable result requires '@_lifetime(...)'}}
 
-  func mutatingMethodNoParam() -> NEImmortal { NEImmortal() }
+  @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
+  func oneParamLifetime_NEResult(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(self)
-  mutating func mutatingMethodNoParamLifetime() -> NEImmortal { NEImmortal() }
+  @_lifetime(copy self) // OK
+  func oneParamCopy_NEResult(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@lifetime(borrow self)' instead}}
-  mutating func mutatingMethodNoParamCopy() -> NEImmortal { NEImmortal() }
+  @_lifetime(borrow self) // OK
+  func oneParamBorrow_NEResult(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(borrow self)
-  mutating func mutatingMethodNoParamBorrow() -> NEImmortal { NEImmortal() }
+  mutating func mutating_oneParam_NEResult(_: Int) -> NonEscapableSelf { self } // expected-error{{a mutating method with a ~Escapable result requires '@_lifetime(...)'}}
 
-  func methodOneParam(_: Int) -> NEImmortal { NEImmortal() } // expected-error{{a method with a ~Escapable result requires '@lifetime(...)'}}
+  @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
+  mutating func mutating_oneParamLifetime_NEResult(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(self)
-  func methodOneParamLifetime(_: Int) -> NEImmortal { NEImmortal() }
+  @_lifetime(copy self) // OK
+  mutating func mutating_oneParamCopy_NEResult(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@lifetime(borrow self)' instead}}
-  func methodOneParamCopy(_: Int) -> NEImmortal { NEImmortal() }
+  @_lifetime(&self) // OK
+  mutating func mutating_oneParamBorrow_NEResult(_: Int) -> NonEscapableSelf { self }
+
+  mutating func mutating_inoutParam_NEResult(a: inout NE) -> NEImmortal { NEImmortal() } // expected-error{{a mutating method with a ~Escapable result requires '@_lifetime(...)'}}
+}
+
+// =============================================================================
+// inout parameter default rule for functions
+// =============================================================================
 
-  @lifetime(borrow self)
-  func methodOneParamBorrow(_: Int) -> NEImmortal { NEImmortal() }
+/* DEFAULT: @_lifetime(ne: copy ne) */
+func inoutNEParam_void(ne: inout NE) {} // OK
 
-  mutating func mutatingMethodOneParam(_: Int) -> NEImmortal { NEImmortal() } // expected-error{{a mutating method with a ~Escapable result requires '@lifetime(...)'}}
+/* DEFAULT: @_lifetime(0: copy 0) */
+func inoutNEParam_NEParam_void(_: inout NE, _: NE) {} // OK
 
-  @lifetime(self)
-  mutating func mutatingMethodOneParamLifetime(_: Int) -> NEImmortal { NEImmortal() }
+/* DEFAULT: @_lifetime(0: copy 0) */
+/* DEFAULT: @_lifetime(1: copy 1) */
+func inoutParam_inoutNEParam_void(_: inout NE, _: inout NE) {} // OK
 
-  @lifetime(copy self) // expected-error{{cannot copy the lifetime of an Escapable type, use '@lifetime(borrow self)' instead}}
-  mutating func mutatingMethodOneParamCopy(_: Int) -> NEImmortal { NEImmortal() }
+func inoutNEParam_NEResult(ne: inout NE) -> NE { ne } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
 
-  @lifetime(borrow self)
-  mutating func mutatingMethodOneParamBorrow(_: Int) -> NEImmortal { NEImmortal() }
+/* DEFAULT: @_lifetime(ne: copy ne) */
+@_lifetime(&ne)
+func inoutNEParam_NEResult_Lifetime(ne: inout NE) -> NE { ne }
+
+// =============================================================================
+// inout parameter default rule for methods
+// =============================================================================
+
+extension EscapableNonTrivialSelf {
+  /* DEFAULT: @_lifetime(ne: copy ne) */
+  func inoutNEParam_void(ne: inout NE) {}
+
+  /* DEFAULT: @_lifetime(ne: copy ne) */
+  mutating func mutating_inoutNEParam_void(ne: inout NE) {}
+
+  /* DEFAULT: @_lifetime(ne: copy NE) */
+  @_lifetime(&ne)
+  func inoutNEParam_NEResult_Lifetime(ne: inout NE) -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(ne: copy NE) */
+  @_lifetime(self)
+  func inoutNEParam_NEResult_LifetimeSelf(ne: inout NE) -> NEImmortal { NEImmortal() }
+}
+
+struct NonEscapableMutableSelf: ~Escapable {
+  // This is unambiguous: inout 'self' needs a dependency, and it can't be a borrow dependency because the original
+  // value is consumed.
+  /* DEFAULT: @_lifetime(self: copy self) */
+  mutating func mutating_noParam_void() {} // OK
+
+  @_lifetime(self: self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
+  mutating func mutating_lifetime_noParam_void() {}
+
+  @_lifetime(self: copy self) // OK
+  mutating func mutating_copyLifetime_noParam_void() {}
+
+  @_lifetime(self: &self) // expected-error{{invalid use of inout dependence on the same inout parameter}}
+                          // expected-note @-1{{use '@_lifetime(self: copy self) to forward the inout dependency}}
+  mutating func mutating_inoutLifetime_noParam_void() {}
+
+  /* DEFAULT: @_lifetime(self: copy self) */
+  mutating func mutating_oneParam_void(_: NE) {}
+
+  @_lifetime(self: self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
+  mutating func mutating_lifetime_oneParam(_: NE) {}
+
+  @_lifetime(self: copy self) // OK
+  mutating func mutating_copyLifetime_oneParam(_: NE) {}
+
+  /* DEFAULT: @_lifetime(self: copy self) */
+  /* DEFAULT: @_lifetime(a: copy a) */
+  mutating func mutating_inoutParam_void(ne: inout NE) {}
+
+  mutating func mutating_noParam_NEResult_noLifetime() -> NEImmortal { NEImmortal() } // expected-error{{a mutating method with a ~Escapable result requires '@_lifetime(...)}}
+
+  /* DEFAULT: @_lifetime(self: copy Self) */
+  @_lifetime(&self)
+  mutating func mutating_noParam_NEResult() -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(self: copy Self) */
+  /* DEFAULT: @_lifetime(ne: copy NE) */
+  @_lifetime(&self)
+  mutating func mutating_inoutNEParam_NEResult(ne: inout NE) -> NEImmortal { NEImmortal() }
 }
 
 // =============================================================================
-// Handle non-Escapable results which must depend on a parameter
-// (for initializers and stand-alone functions)
+// non-Escapable Initialization
 // =============================================================================
 
+// An implicit initializer illegally consumes its nontrivial parameter.
+public struct NonescapableImplicitInitializer: ~Escapable {
+  // expected-error @-1{{cannot borrow the lifetime of 'c', which has consuming ownership on an implicit initializer}}
+  var c: C
+}
+
 struct NonescapableInitializers: ~Escapable {
   var c: C
 
   init() { c = C() } // expected-error{{an initializer with a ~Escapable result needs a parameter to depend on}}
-  // expected-note@-1{{'@lifetime(immortal)' can be used to indicate that values produced by this initializer have no lifetime dependencies}}
+  // expected-note@-1{{'@_lifetime(immortal)' can be used to indicate that values produced by this initializer have no lifetime dependencies}}
  
   init(c: C) { self.c = c } // expected-error{{cannot borrow the lifetime of 'c', which has consuming ownership on an initializer}}
 
-  init(c: C, _: Int) { self.c = c } // expected-error{{an initializer with a ~Escapable result requires '@lifetime(...)'}}
+  init(c: C, _: Int) { self.c = c } // expected-error{{an initializer with a ~Escapable result requires '@_lifetime(...)'}}
 
-  init(ne: NE) { c = C() } // expected-error{{cannot infer the lifetime dependence scope on an initializer with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+  init(ne: NE) { c = C() } // expected-error{{cannot infer the lifetime dependence scope on an initializer with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
 }
 
 struct NonescapableConsumingInitializers: ~Escapable {
@@ -186,9 +358,9 @@ struct NonescapableConsumingInitializers: ~Escapable {
 
   init(c: consuming C) { self.c = c } // expected-error{{cannot borrow the lifetime of 'c', which has consuming ownership on an initializer}}
 
-  init(c: consuming C, _: Int) { self.c = c } // expected-error{{an initializer with a ~Escapable result requires '@lifetime(...)'}}
+  init(c: consuming C, _: Int) { self.c = c } // expected-error{{an initializer with a ~Escapable result requires '@_lifetime(...)'}}
 
-  init(ne: consuming NE) { c = C() } // expected-error{{cannot infer the lifetime dependence scope on an initializer with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+  init(ne: consuming NE) { c = C() } // expected-error{{cannot infer the lifetime dependence scope on an initializer with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
 }
 
 struct NonescapableBorrowingInitializers: ~Escapable {
@@ -196,9 +368,9 @@ struct NonescapableBorrowingInitializers: ~Escapable {
 
   init(c: borrowing C) { self.c = c } // OK
 
-  init(c: borrowing C, _: Int) { self.c = c } // expected-error{{an initializer with a ~Escapable result requires '@lifetime(...)'}}
+  init(c: borrowing C, _: Int) { self.c = c } // expected-error{{an initializer with a ~Escapable result requires '@_lifetime(...)'}}
 
-  init(ne: borrowing NE) { c = C() } // expected-error{{cannot infer the lifetime dependence scope on an initializer with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+  init(ne: borrowing NE) { c = C() } // expected-error{{cannot infer the lifetime dependence scope on an initializer with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
 }
 
 struct NonescapableInoutInitializers: ~Escapable {
@@ -206,72 +378,61 @@ struct NonescapableInoutInitializers: ~Escapable {
 
   init(c: inout C) { self.c = c } // OK
 
-  init(c: inout C, _: Int) { self.c = c } // expected-error{{an initializer with a ~Escapable result requires '@lifetime(...)'}}
+  init(c: inout C, _: Int) { self.c = c } // expected-error{{an initializer with a ~Escapable result requires '@_lifetime(...)'}}
 
-  init(ne: inout NE) { c = C() } // expected-error{{cannot infer the lifetime dependence scope on an initializer with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+  init(ne: inout NE) { c = C() } // expected-error{{cannot infer the lifetime dependence scope on an initializer with a ~Escapable parameter, specify '@_lifetime(borrow ne)' or '@_lifetime(copy ne)'}}
 }
 
-func noParam() -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result needs a parameter to depend on}}
-// expected-note@-1{{'@lifetime(immortal)' can be used to indicate that values produced by this initializer have no lifetime dependencies}}
-
-@lifetime(immortal)
-func noParamImmortal() -> NEImmortal { NEImmortal() } // OK
-
-func oneParam(c: C) -> NEImmortal { NEImmortal() }
-
-@lifetime(c)
-func oneParamLifetime(c: C) -> NEImmortal { NEImmortal() }
-
-func oneParamConsume(c: consuming C) -> NEImmortal { NEImmortal() } // expected-error{{cannot borrow the lifetime of 'c', which has consuming ownership on a function}}
-
-@lifetime(c) // expected-error{{invalid use of borrow dependence with consuming ownership}}
-func oneParamConsumeLifetime(c: consuming C) -> NEImmortal { NEImmortal() }
-
-func oneParamBorrow(c: borrowing C) -> NEImmortal { NEImmortal() } // OK
-
-@lifetime(c)
-func oneParamBorrowLifetime(c: borrowing C) -> NEImmortal { NEImmortal() } // OK
-
-func oneParamInout(c: inout C) -> NEImmortal { NEImmortal() } // OK
-
-@lifetime(c)
-func oneParamInoutLifetime(c: inout C) -> NEImmortal { NEImmortal() } // OK
-
-func twoParams(c: C, _: Int) -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result requires '@lifetime(...)'}}
-
-@lifetime(c)
-func twoParamsLifetime(c: C, _: Int) -> NEImmortal { NEImmortal() }
-
-func twoParamsConsume(c: consuming C, _: Int) -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result requires '@lifetime(...)'}}
-
-func twoParamsBorrow(c: borrowing C, _: Int) -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result requires '@lifetime(...)'}}
-
-func twoParamsInout(c: inout C, _: Int) -> NEImmortal { NEImmortal() } // expected-error{{a function with a ~Escapable result requires '@lifetime(...)'}}
-
-func neParam(ne: NE) -> NE { ne } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+// =============================================================================
+// Aggregate initialization
+// =============================================================================
 
-@lifetime(ne) // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
-func neParamLifetime(ne: NE) -> NE { ne }
+// Motivation: Non-escapable struct definitions often have inicidental integer fields that are unrelated to lifetime.
+// Without an explicit initializer, the compiler would infer these fields to be borrowed by the implicit intializer.
+// This inevitabely results in lifetime diagnostic errors elsewhere in the code that can't be tracked down at the use
+// site:
+//
+//     let span = CountedSpan(span: span, i: 3) // ERROR: span depends on the lifetime of this value
+//
+struct CountedSpan: ~Escapable { // expected-error{{cannot infer implicit initialization lifetime. Add an initializer with '@_lifetime(...)' for each parameter the result depends on}}
+  let span: Span<Int>
+  let i: Int
+}
 
-func neParamBorrow(ne: borrowing NE) -> NE { ne } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+struct NE_Int: ~Escapable {
+  let i: Int
+}
 
-@lifetime(ne) // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
-func neParamBorrowLifetime(ne: borrowing NE) -> NE { ne }
+struct NE_C: ~Escapable { // expected-error{{cannot borrow the lifetime of 'c', which has consuming ownership on an implicit initializer}}
+  let c: C
+}
 
-func neParamConsume(ne: consuming NE) -> NE { ne } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+struct NE_C_Int: ~Escapable { // expected-error{{cannot infer implicit initialization lifetime. Add an initializer with '@_lifetime(...)' for each parameter the result depends on}}
+  let c: C
+  let i: Int
+}
 
-@lifetime(ne) // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
-func neParamConsumeLifetime(ne: consuming NE) -> NE { ne }
+struct NE_Int_Int: ~Escapable { // expected-error{{cannot infer implicit initialization lifetime. Add an initializer with '@_lifetime(...)' for each parameter the result depends on}}
+  let i: Int
+  let j: Int
+}
 
-func neParamInout(ne: inout NE) -> NE { ne } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
+struct NE_NE: ~Escapable {
+  let ne: NE
+}
 
-@lifetime(ne) // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow ne)' or '@lifetime(copy ne)'}}
-func neParamInoutLifetime(ne: inout NE) -> NE { ne }
+struct NE_NE_Int: ~Escapable { // expected-error{{cannot infer implicit initialization lifetime. Add an initializer with '@_lifetime(...)' for each parameter the result depends on}}
+  let ne: NE
+  let i: Int
+}
 
-func neTwoParam(ne: NE, _:Int) -> NE { ne } // expected-error{{a function with a ~Escapable result requires '@lifetime(...)'}}
+struct NE_NE_C: ~Escapable { // expected-error{{cannot infer implicit initialization lifetime. Add an initializer with '@_lifetime(...)' for each parameter the result depends on}}
+  let ne: NE
+  let c: C
+}
 
 // =============================================================================
-// Handle Accessors:
+// Accessors:
 //
 // 'get', '_read', and '_modify' are inferred as methods that return ~Escpable results dependent on 'self'
 //
@@ -284,6 +445,47 @@ struct Accessors {
   let c: C
 
   var neComputed: NEImmortal {
+    /* DEFAULT: @_lifetime(borrow self) */
+    get { // OK
+      NEImmortal()
+    }
+
+    set { // OK (no dependency)
+    }
+  }
+
+  var neYielded: NEImmortal {
+    /* DEFAULT: @_lifetime(borrow self) */
+    _read { // OK
+      yield NEImmortal()
+    }
+
+    /* DEFAULT: @_lifetime(borrow self) */
+    _modify { // OK
+      var ne = NEImmortal()
+      yield &ne
+    }
+  }
+
+  // Synthesized _modify...
+  subscript(_ index: Int) -> NEImmortal {
+    /* DEFAULT: @_lifetime(borrow self) */
+    get { // OK
+      NEImmortal()
+    }
+
+    set { // OK (no dependency)
+    }
+  }
+}
+
+struct TrivialAccessors {
+  let p: UnsafeRawPointer
+
+  // The implicit _read/_modify accessors must be inferred. They cannot be written explicitly because a getter is
+  // already defined.
+  var neComputed: NEImmortal {
+    @_lifetime(borrow self)
     get { // OK
       NEImmortal()
     }
@@ -293,10 +495,12 @@ struct Accessors {
   }
 
   var neYielded: NEImmortal {
+    @_lifetime(borrow self)
     _read { // OK
       yield NEImmortal()
     }
 
+    @_lifetime(&self)
     _modify { // OK
       var ne = NEImmortal()
       yield &ne
@@ -307,99 +511,100 @@ struct Accessors {
 struct NonescapableSelfAccessors: ~Escapable {
   var ne: NE
 
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init() {
     ne = NE()
   }
 
   var neComputed: NE {
-    get { // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    get { // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
       ne
     }
 
-    set { // expected-error{{a mutating method with a ~Escapable 'self' requires '@lifetime(self: ...)'}}
+    // DEFAULT: '@_lifetime(self: copy self, copy newValue)
+    set {
       ne = newValue
     }
   }
 
   var neYielded: NE {
-    _read { // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    _read { // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
       yield ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &ne
     }
   }
 
   var neComputedLifetime: NE {
-    @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
     get {
       ne
     }
 
-    @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    @_lifetime(self: newValue) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@_lifetime(borrow newValue)' or '@_lifetime(copy newValue)'}}
     set {
       ne = newValue
     }
   }
 
   var neYieldedLifetime: NE {
-    @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
     _read {
       yield ne
     }
 
-    @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
     _modify {
       yield &ne
     }
   }
 
   var neComputedCopy: NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     get {
       ne
     }
 
-    @lifetime(copy self)
+    @_lifetime(self: copy newValue)
     set {
       ne = newValue
     }
   }
 
   var neYieldedCopy: NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield ne
     }
 
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _modify {
       yield &ne
     }
   }
 
   var neComputedBorrow: NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     get {
       ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(self: borrow newValue)
     set {
       ne = newValue
     }
   }
 
   var neYieldedBorrow: NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     _read {
       yield ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &ne
     }
@@ -410,126 +615,111 @@ struct NoncopyableSelfAccessors: ~Copyable & ~Escapable {
   var ne: NE
 
   var neComputed: NE {
-    get { // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    get { // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
       ne
     }
 
-    set { // expected-error{{a mutating method with a ~Escapable 'self' requires '@lifetime(self: ...)'}}
+    // DEFAULT: '@_lifetime(self: copy self, copy newValue)
+    set {
       ne = newValue
     }
   }
 
   var neYielded: NE {
-    _read { // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    _read { // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
       yield ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &ne
     }
   }
 
   var neComputedLifetime: NE {
-    @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
     get {
       ne
     }
 
-    @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    @_lifetime(self: newValue) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@_lifetime(borrow newValue)' or '@_lifetime(copy newValue)'}}
     set {
       ne = newValue
     }
   }
 
   var neYieldedLifetime: NE {
-    @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
     _read {
       yield ne
     }
 
-    @lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
+    @_lifetime(self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@_lifetime(borrow self)' or '@_lifetime(copy self)'}}
     _modify {
       yield &ne
     }
   }
 
   var neComputedCopy: NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     get {
       ne
     }
 
-    @lifetime(copy self)
+    @_lifetime(self: copy newValue)
     set {
       ne = newValue
     }
   }
 
   var neYieldedCopy: NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield ne
     }
 
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _modify {
       yield &ne
     }
   }
 
   var neComputedBorrow: NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     get {
       ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(self: copy newValue)
     set {
       ne = newValue
     }
   }
 
   var neYieldedBorrow: NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     _read {
       yield ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &ne
     }
   }
 }
 
-// =============================================================================
-// Handle mutating methods with no return value
-// =============================================================================
-
-struct NonEscapableMutableSelf: ~Escapable {
-  // This is unambiguous: inout 'self' needs a dependency, and it can't be a borrow dependency because the original
-  // value is consumed.
-  /* @lifetime(self: copy self) */
-  mutating func mutatingMethodNoParam() {} // OK
-
-  @lifetime(self: self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
-  mutating func mutatingMethodNoParamLifetime() {}
-
-  @lifetime(self: copy self) // OK
-  mutating func mutatingMethodNoParamCopy() {}
-
-  @lifetime(self: borrow self) // expected-error{{invalid use of borrow dependence on the same inout parameter}}
-  mutating func mutatingMethodNoParamBorrow() {}
-
-  mutating func mutatingMethodOneParam(_: NE) {} // expected-error{{a mutating method with a ~Escapable 'self' requires '@lifetime(self: ...)'}}
+// ==================================================================================
+// Common mistakes with inout parameter annotations requiring custom diagnostics...
+// ==================================================================================
 
-  @lifetime(self: self) // expected-error{{cannot infer the lifetime dependence scope on a mutating method with a ~Escapable parameter, specify '@lifetime(borrow self)' or '@lifetime(copy self)'}}
-  mutating func mutatingMethodOneParamLifetime(_: NE) {}
-
-  @lifetime(copy self) // OK
-  mutating func mutatingMethodOneParamCopy(_: NE) {}
+// Invalid keyword for the dependence kind.
+//
+@_lifetime(a: inout a) // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier, index or 'self' in lifetime dependence specifier}}
+func f_inout_bad_keyword(a: inout MutableRawSpan) {}
 
-  @lifetime(borrow self)
-  mutating func mutatingMethodOneParamBorrow(_: NE) {}
-}
+// Don't allow a useless borrow dependency on an inout param--it is misleading.
+//
+@_lifetime(a: &a) // expected-error{{invalid use of inout dependence on the same inout parameter}}
+                  // expected-note @-1{{use '@_lifetime(a: copy a) to forward the inout dependency}}
+func f_inout_useless(a: inout MutableRawSpan) {}
diff --git a/test/Sema/lifetime_depend_infer_defaults.swift b/test/Sema/lifetime_depend_infer_defaults.swift
new file mode 100644
index 0000000000000..e69e351c2debd
--- /dev/null
+++ b/test/Sema/lifetime_depend_infer_defaults.swift
@@ -0,0 +1,299 @@
+// RUN: %target-swift-emit-silgen -enable-experimental-feature Lifetimes -primary-file %s | %FileCheck %s
+//
+// -primary-file is required to synthesize accessors.
+
+// REQUIRES: swift_feature_Lifetimes
+
+// Check that all the DEFAULT cases in Sema/lifetime_depend_infer_defaults.swift generate the correct function
+// signature. Checking the SILGen output seems like the easiest way.
+
+class C {}
+
+struct NE: ~Escapable {}
+
+struct NEImmortal: ~Escapable {
+  @_lifetime(immortal)
+  init() {}
+}
+
+struct MutNE: ~Copyable & ~Escapable {}
+
+// =============================================================================
+// Single parameter default rule for functions
+// =============================================================================
+
+/* DEFAULT: @_lifetime(borrow i) */
+// CHECK: @$s30lifetime_depend_infer_defaults24oneTrivialParam_NEResult1iAA10NEImmortalVSi_tF : $@convention(thin) (Int) -> @lifetime(borrow 0) @owned NEImmortal
+func oneTrivialParam_NEResult(i: Int) -> NEImmortal { NEImmortal() }
+
+/* DEFAULT: @_lifetime(borrow c) */
+// CHECK: @$s30lifetime_depend_infer_defaults17oneParam_NEResult1cAA10NEImmortalVAA1CC_tF : $@convention(thin) (@guaranteed C) -> @lifetime(borrow 0) @owned NEImmortal
+func oneParam_NEResult(c: C) -> NEImmortal { NEImmortal() }
+
+/* DEFAULT: @_lifetime(borrow c) */
+// CHECK: @$s30lifetime_depend_infer_defaults25oneParamLifetime_NEResult1cAA10NEImmortalVAA1CC_tF : $@convention(thin) (@guaranteed C) -> @lifetime(borrow 0) @owned NEImmortal
+@_lifetime(c)
+func oneParamLifetime_NEResult(c: C) -> NEImmortal { NEImmortal() }
+
+/* DEFAULT: @_lifetime(borrow c) */
+// CHECK: @$s30lifetime_depend_infer_defaults23oneParamBorrow_NEResult1cAA10NEImmortalVAA1CC_tF : $@convention(thin) (@guaranteed C) -> @lifetime(borrow 0) @owned NEImmortal
+func oneParamBorrow_NEResult(c: borrowing C) -> NEImmortal { NEImmortal() } // OK
+
+/* DEFAULT: @_lifetime(borrow c) */
+// CHECK: @$s30lifetime_depend_infer_defaults31oneParamBorrowLifetime_NEResult1cAA10NEImmortalVAA1CC_tF : $@convention(thin) (@guaranteed C) -> @lifetime(borrow 0) @owned NEImmortal
+@_lifetime(c)
+func oneParamBorrowLifetime_NEResult(c: borrowing C) -> NEImmortal { NEImmortal() } // OK
+
+/* DEFAULT: @_lifetime(&c) */
+// CHECK: @$s30lifetime_depend_infer_defaults22oneInoutParam_NEResult1cAA10NEImmortalVAA1CCz_tF : $@convention(thin) (@inout C) -> @lifetime(borrow 0) @owned NEImmortal
+func oneInoutParam_NEResult(c: inout C) -> NEImmortal { NEImmortal() } // OK
+
+/* DEFAULT: @_lifetime(&c) */
+// CHECK: @$s30lifetime_depend_infer_defaults30oneParamInoutLifetime_NEResult1cAA10NEImmortalVAA1CCz_tF : $@convention(thin) (@inout C) -> @lifetime(borrow 0) @owned NEImmortal
+@_lifetime(c)
+func oneParamInoutLifetime_NEResult(c: inout C) -> NEImmortal { NEImmortal() } // OK
+
+// =============================================================================
+// Single parameter default rule for methods
+// =============================================================================
+
+struct EscapableNonTrivialSelf {
+  let c: C
+
+  init(c: C) { self.c = c }
+
+  /* DEFAULT: @_lifetime(borrow self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23EscapableNonTrivialSelfV16noParam_NEResultAA10NEImmortalVyF : $@convention(method) (@guaranteed EscapableNonTrivialSelf) -> @lifetime(borrow 0) @owned NEImmortal
+  func noParam_NEResult() -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(borrow self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23EscapableNonTrivialSelfV24noParamLifetime_NEResultAA10NEImmortalVyF : $@convention(method) (@guaranteed EscapableNonTrivialSelf) -> @lifetime(borrow 0) @owned NEImmortal
+  @_lifetime(self)
+  func noParamLifetime_NEResult() -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(&self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23EscapableNonTrivialSelfV25mutating_noParam_NEResultAA10NEImmortalVyF : $@convention(method) (@inout EscapableNonTrivialSelf) -> @lifetime(borrow 0) @owned NEImmortal
+  mutating func mutating_noParam_NEResult() -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(&self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23EscapableNonTrivialSelfV33mutating_noParamLifetime_NEResultAA10NEImmortalVyF : $@convention(method) (@inout EscapableNonTrivialSelf) -> @lifetime(borrow 0) @owned NEImmortal
+  @_lifetime(self)
+  mutating func mutating_noParamLifetime_NEResult() -> NEImmortal { NEImmortal() }
+}
+
+struct EscapableTrivialSelf {
+  /* DEFAULT: @_lifetime(borrow self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults20EscapableTrivialSelfV24noParamLifetime_NEResultAA10NEImmortalVyF : $@convention(method) (EscapableTrivialSelf) -> @lifetime(borrow 0) @owned NEImmortal
+  @_lifetime(self) // OK
+  func noParamLifetime_NEResult() -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(borrow self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults20EscapableTrivialSelfV38mutatingMethodNoParamLifetime_NEResultAA10NEImmortalVyF : $@convention(method) (@inout EscapableTrivialSelf) -> @lifetime(borrow 0) @owned NEImmortal
+  @_lifetime(self) // OK
+  mutating func mutatingMethodNoParamLifetime_NEResult() -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(borrow self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults20EscapableTrivialSelfV25oneParamLifetime_NEResultyAA10NEImmortalVSiF : $@convention(method) (Int, EscapableTrivialSelf) -> @lifetime(borrow 1) @owned NEImmortal
+  @_lifetime(self)
+  func oneParamLifetime_NEResult(_: Int) -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(borrow self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults20EscapableTrivialSelfV34mutating_oneParamLifetime_NEResultyAA10NEImmortalVSiF : $@convention(method) (Int, @inout EscapableTrivialSelf) -> @lifetime(borrow 1) @owned NEImmortal
+  @_lifetime(self)
+  mutating func mutating_oneParamLifetime_NEResult(_: Int) -> NEImmortal { NEImmortal() }
+}
+
+// =============================================================================
+// inout parameter default rule for functions
+// =============================================================================
+
+/* DEFAULT: @_lifetime(ne: copy ne) */
+// CHECK: @$s30lifetime_depend_infer_defaults17inoutNEParam_void2neyAA2NEVz_tF : $@convention(thin) (@lifetime(copy 0) @inout NE) -> ()
+func inoutNEParam_void(ne: inout NE) {} // OK
+
+/* DEFAULT: @_lifetime(0: copy 0) */
+// CHECK: @$s30lifetime_depend_infer_defaults013inoutNEParam_F5_voidyyAA2NEVz_ADtF : $@convention(thin) (@lifetime(copy 0) @inout NE, @guaranteed NE) -> ()
+func inoutNEParam_NEParam_void(_: inout NE, _: NE) {} // OK
+
+/* DEFAULT: @_lifetime(0: copy 0) */
+/* DEFAULT: @_lifetime(1: copy 1) */
+// CHECK: @$s30lifetime_depend_infer_defaults011inoutParam_E12NEParam_voidyyAA2NEVz_ADztF : $@convention(thin) (@lifetime(copy 0) @inout NE, @lifetime(copy 1) @inout NE) -> ()
+func inoutParam_inoutNEParam_void(_: inout NE, _: inout NE) {} // OK
+
+/* DEFAULT: @_lifetime(ne: copy ne) */
+// CHECK: @$s30lifetime_depend_infer_defaults30inoutNEParam_NEResult_Lifetime2neAA2NEVAEz_tF : $@convention(thin) (@lifetime(copy 0) @inout NE) -> @lifetime(borrow 0) @owned NE
+@_lifetime(&ne)
+func inoutNEParam_NEResult_Lifetime(ne: inout NE) -> NE { ne }
+
+// =============================================================================
+// inout parameter default rule for methods
+// =============================================================================
+
+extension EscapableNonTrivialSelf {
+  /* DEFAULT: @_lifetime(ne: copy ne) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23EscapableNonTrivialSelfV17inoutNEParam_void2neyAA2NEVz_tF : $@convention(method) (@lifetime(copy 0) @inout NE, @guaranteed EscapableNonTrivialSelf) -> ()
+  func inoutNEParam_void(ne: inout NE) {}
+
+  /* DEFAULT: @_lifetime(ne: copy ne) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23EscapableNonTrivialSelfV26mutating_inoutNEParam_void2neyAA2NEVz_tF : $@convention(method) (@lifetime(copy 0) @inout NE, @inout EscapableNonTrivialSelf) -> ()
+  mutating func mutating_inoutNEParam_void(ne: inout NE) {}
+
+  /* DEFAULT: @_lifetime(ne: copy NE) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23EscapableNonTrivialSelfV30inoutNEParam_NEResult_Lifetime2neAA10NEImmortalVAA2NEVz_tF : $@convention(method) (@lifetime(copy 0) @inout NE, @guaranteed EscapableNonTrivialSelf) -> @lifetime(borrow 0) @owned NEImmortal
+  @_lifetime(&ne)
+  func inoutNEParam_NEResult_Lifetime(ne: inout NE) -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(ne: copy NE) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23EscapableNonTrivialSelfV030inoutNEParam_NEResult_LifetimeH02neAA10NEImmortalVAA2NEVz_tF : $@convention(method) (@lifetime(copy 0) @inout NE, @guaranteed EscapableNonTrivialSelf) -> @lifetime(borrow 1) @owned NEImmortal
+  @_lifetime(self)
+  func inoutNEParam_NEResult_LifetimeSelf(ne: inout NE) -> NEImmortal { NEImmortal() }
+}
+
+struct NonEscapableMutableSelf: ~Escapable {
+  // This is unambiguous: inout 'self' needs a dependency, and it can't be a borrow dependency because the original
+  // value is consumed.
+  /* DEFAULT: @_lifetime(self: copy self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23NonEscapableMutableSelfV21mutating_noParam_voidyyF : $@convention(method) (@lifetime(copy 0) @inout NonEscapableMutableSelf) -> ()
+  mutating func mutating_noParam_void() {} // OK
+
+  /* DEFAULT: @_lifetime(self: copy self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23NonEscapableMutableSelfV22mutating_oneParam_voidyyAA2NEVF : $@convention(method) (@guaranteed NE, @lifetime(copy 1) @inout NonEscapableMutableSelf) -> ()
+  mutating func mutating_oneParam_void(_: NE) {}
+
+  /* DEFAULT: @_lifetime(self: copy self) */
+  /* DEFAULT: @_lifetime(a: copy a) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23NonEscapableMutableSelfV24mutating_inoutParam_void2neyAA2NEVz_tF : $@convention(method) (@lifetime(copy 0) @inout NE, @lifetime(copy 1) @inout NonEscapableMutableSelf) -> ()
+  mutating func mutating_inoutParam_void(ne: inout NE) {}
+
+  /* DEFAULT: @_lifetime(self: copy Self) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23NonEscapableMutableSelfV25mutating_noParam_NEResultAA10NEImmortalVyF : $@convention(method) (@lifetime(copy 0) @inout NonEscapableMutableSelf) -> @lifetime(borrow 0) @owned NEImmortal
+  @_lifetime(&self)
+  mutating func mutating_noParam_NEResult() -> NEImmortal { NEImmortal() }
+
+  /* DEFAULT: @_lifetime(self: copy Self) */
+  /* DEFAULT: @_lifetime(ne: copy NE) */
+  // CHECK: @$s30lifetime_depend_infer_defaults23NonEscapableMutableSelfV30mutating_inoutNEParam_NEResult2neAA10NEImmortalVAA2NEVz_tF : $@convention(method) (@lifetime(copy 0) @inout NE, @lifetime(copy 1) @inout NonEscapableMutableSelf) -> @lifetime(borrow 1) @owned NEImmortal
+  @_lifetime(&self)
+  mutating func mutating_inoutNEParam_NEResult(ne: inout NE) -> NEImmortal { NEImmortal() }
+}
+
+// =============================================================================
+// Accessors:
+//
+// 'get', '_read', and '_modify' are inferred as methods that return ~Escpable results dependent on 'self'
+//
+// 'set' is only inferred when implicit. This allows for the declaration of non-Escapable stored properties. Knowing
+// that the implicit setter assigns a stored property is sufficient for the compiler to assume Inherit dependency on
+// both 'self' and 'newValue'. A full assignment would not need the 'self' dependency.
+// =============================================================================
+
+struct Accessors {
+  let c: C
+
+  var neComputed: NEImmortal {
+    /* DEFAULT: @_lifetime(borrow self) */
+    // CHECK: @$s30lifetime_depend_infer_defaults9AccessorsV10neComputedAA10NEImmortalVvg : $@convention(method) (@guaranteed Accessors) -> @lifetime(borrow 0) @owned NEImmortal
+    get { // OK
+      NEImmortal()
+    }
+
+    // CHECK: @$s30lifetime_depend_infer_defaults9AccessorsV10neComputedAA10NEImmortalVvs : $@convention(method) (@owned NEImmortal, @inout Accessors) -> ()
+    set { // OK (no dependency)
+    }
+  }
+
+  var neYielded: NEImmortal {
+    /* DEFAULT: @_lifetime(borrow self) */
+    // CHECK: @$s30lifetime_depend_infer_defaults9AccessorsV9neYieldedAA10NEImmortalVvr : $@yield_once @convention(method) (@guaranteed Accessors) -> @lifetime(borrow 0) @yields @guaranteed NEImmortal
+    _read { // OK
+      yield NEImmortal()
+    }
+
+    /* DEFAULT: @_lifetime(borrow self) */
+    // CHECK: @$s30lifetime_depend_infer_defaults9AccessorsV9neYieldedAA10NEImmortalVvM : $@yield_once @convention(method) (@inout Accessors) -> @lifetime(borrow 0) @yields @inout NEImmortal
+    _modify { // OK
+      var ne = NEImmortal()
+      yield &ne
+    }
+  }
+
+  subscript(_ index: Int) -> NEImmortal {
+    /* DEFAULT: @_lifetime(borrow self) */
+    // CHECK: @$s30lifetime_depend_infer_defaults9AccessorsVyAA10NEImmortalVSicig : $@convention(method) (Int, @guaranteed Accessors) -> @lifetime(borrow 1) @owned NEImmortal
+    get { // OK
+      NEImmortal()
+    }
+
+    // CHECK: @$s30lifetime_depend_infer_defaults9AccessorsVyAA10NEImmortalVSicis : $@convention(method) (@owned NEImmortal, Int, @inout Accessors) -> ()
+    set { // OK (no dependency)
+    }
+
+    // Synthesized modify...
+    /* DEFAULT: @_lifetime(borrow self) */
+    // CHECK: @$s30lifetime_depend_infer_defaults9AccessorsVyAA10NEImmortalVSiciM : $@yield_once @convention(method) (Int, @inout Accessors) -> @lifetime(borrow 1) @yields @inout NEImmortal
+  }
+}
+
+struct TrivialAccessors {
+  let p: UnsafeRawPointer
+
+  // The implicit _read/_modify accessors must be inferred. They cannot be written explicitly because a getter is
+  // already defined.
+  var neComputed: NEImmortal {
+    @_lifetime(borrow self)
+    get { // OK
+      NEImmortal()
+    }
+
+    // CHECK: @$s30lifetime_depend_infer_defaults16TrivialAccessorsV10neComputedAA10NEImmortalVvs : $@convention(method) (@owned NEImmortal, @inout TrivialAccessors) -> ()
+    set { // OK (no dependency)
+    }
+
+    // synthesized modify
+    // CHECK: @$s30lifetime_depend_infer_defaults16TrivialAccessorsV10neComputedAA10NEImmortalVvM : $@yield_once @convention(method) (@inout TrivialAccessors) -> @lifetime(borrow 0) @yields @inout NEImmortal
+  }
+}
+
+struct NonescapableSelfAccessors: ~Escapable {
+  var ne: NE
+
+  @_lifetime(immortal)
+  init() {
+    ne = NE()
+  }
+
+  var neComputed: NE {
+    @_lifetime(copy self)
+    get {
+      ne
+    }
+    // DEFAULT: '@_lifetime(self: copy self, copy newValue)
+    // CHECK: @$s30lifetime_depend_infer_defaults25NonescapableSelfAccessorsV10neComputedAA2NEVvs : $@convention(method) (@owned NE, @lifetime(copy 0, copy 1) @inout NonescapableSelfAccessors) -> ()
+    set {
+      ne = newValue
+    }
+
+    // synthesized modify.
+    // CHECK: @$s30lifetime_depend_infer_defaults25NonescapableSelfAccessorsV10neComputedAA2NEVvM : $@yield_once @convention(method) (@lifetime(copy 0) @inout NonescapableSelfAccessors) -> @lifetime(copy 0) @yields @inout NE
+  }
+}
+
+struct NoncopyableSelfAccessors: ~Copyable & ~Escapable {
+  var ne: NE
+
+  var neComputed: NE {
+    @_lifetime(copy self)
+    get {
+      ne
+    }
+    // DEFAULT: '@_lifetime(self: copy self, copy newValue)
+    // CHECK: @$s30lifetime_depend_infer_defaults24NoncopyableSelfAccessorsV10neComputedAA2NEVvs : $@convention(method) (@owned NE, @lifetime(copy 0, copy 1) @inout NoncopyableSelfAccessors) -> ()
+    set {
+      ne = newValue
+    }
+
+    // synthesized modify.
+    // CHECK: @$s30lifetime_depend_infer_defaults24NoncopyableSelfAccessorsV10neComputedAA2NEVvM : $@yield_once @convention(method) (@lifetime(copy 0) @inout NoncopyableSelfAccessors) -> @lifetime(copy 0) @yields @inout NE
+  }
+
+}
diff --git a/test/Sema/lifetime_depend_infer_interface.swift b/test/Sema/lifetime_depend_infer_interface.swift
index 217e4d9602936..487ba383ad6b8 100644
--- a/test/Sema/lifetime_depend_infer_interface.swift
+++ b/test/Sema/lifetime_depend_infer_interface.swift
@@ -7,6 +7,6 @@
 
 // Test that type checking continues to handle inference of lifetime
 // dependencies that may be required in older (early
-// 2025) .swiftinterface files. Source-level type checking is more strict.
+// 2025) .swiftinterface files. Source-level type checking is stricter.
 
 import lifetime_depend_infer
diff --git a/test/Sema/lifetime_depend_infer_lazy.swift b/test/Sema/lifetime_depend_infer_lazy.swift
index 12b92d69f19c2..0868a8aaa2951 100644
--- a/test/Sema/lifetime_depend_infer_lazy.swift
+++ b/test/Sema/lifetime_depend_infer_lazy.swift
@@ -1,8 +1,8 @@
 // RUN: %target-typecheck-verify-swift \
-// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN:   -enable-experimental-feature Lifetimes \
 // RUN:   -enable-experimental-lifetime-dependence-inference
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // Coverage testing for LifetimeDependence inferrence logic. The tests are grouped according to the design of
 // LifetimeDependenceChecker.
@@ -12,7 +12,7 @@ class C {}
 struct NE: ~Escapable {}
 
 struct NEImmortal: ~Escapable {
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init() {}
 }
 
@@ -23,68 +23,68 @@ struct NEImmortal: ~Escapable {
 struct NonEscapableSelf: ~Escapable {
   func methodNoParam() -> NonEscapableSelf { self } // OK
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   func methodNoParamLifetime() -> NonEscapableSelf { self }
 
-  @lifetime(copy self) // OK
+  @_lifetime(copy self) // OK
   func methodNoParamCopy() -> NonEscapableSelf { self }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(borrow self) // OK
   func methodNoParamBorrow() -> NonEscapableSelf { self }
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   mutating func mutatingMethodNoParamLifetime() -> NonEscapableSelf { self }
 
-  @lifetime(copy self) // OK
+  @_lifetime(copy self) // OK
   mutating func mutatingMethodNoParamCopy() -> NonEscapableSelf { self }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(&self) // OK
   mutating func mutatingMethodNoParamBorrow() -> NonEscapableSelf { self }
 
   func methodOneParam(_: Int) -> NonEscapableSelf { self } // OK
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   func methodOneParamLifetime(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(copy self) // OK
+  @_lifetime(copy self) // OK
   func methodOneParamCopy(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(borrow self) // OK
   func methodOneParamBorrow(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   mutating func mutatingMethodOneParamLifetime(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(copy self) // OK
+  @_lifetime(copy self) // OK
   mutating func mutatingMethodOneParamCopy(_: Int) -> NonEscapableSelf { self }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(&self) // OK
   mutating func mutatingMethodOneParamBorrow(_: Int) -> NonEscapableSelf { self }
 }
 
 struct EscapableTrivialSelf {
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   func methodNoParamLifetime() -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(borrow self) // OK
   func methodNoParamBorrow() -> NEImmortal { NEImmortal() }
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   mutating func mutatingMethodNoParamLifetime() -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(&self) // OK
   mutating func mutatingMethodNoParamBorrow() -> NEImmortal { NEImmortal() }
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   func methodOneParamLifetime(_: Int) -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(borrow self) // OK
   func methodOneParamBorrow(_: Int) -> NEImmortal { NEImmortal() }
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   mutating func mutatingMethodOneParamLifetime(_: Int) -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self)
+  @_lifetime(&self)
   mutating func mutatingMethodOneParamBorrow(_: Int) -> NEImmortal { NEImmortal() }
 }
 
@@ -95,34 +95,34 @@ struct EscapableNonTrivialSelf {
 
   func methodNoParam() -> NEImmortal { NEImmortal() } // OK
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   func methodNoParamLifetime() -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(borrow self) // OK
   func methodNoParamBorrow() -> NEImmortal { NEImmortal() }
 
   func mutatingMethodNoParam() -> NEImmortal { NEImmortal() } // OK
 
-  @lifetime(self)
+  @_lifetime(self)
   mutating func mutatingMethodNoParamLifetime() -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self)
+  @_lifetime(&self)
   mutating func mutatingMethodNoParamBorrow() -> NEImmortal { NEImmortal() }
 
   func methodOneParam(_: Int) -> NEImmortal { NEImmortal() } // OK
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   func methodOneParamLifetime(_: Int) -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(borrow self) // OK
   func methodOneParamBorrow(_: Int) -> NEImmortal { NEImmortal() }
 
   mutating func mutatingMethodOneParam(_: Int) -> NEImmortal { NEImmortal() } // OK
 
-  @lifetime(self) // OK
+  @_lifetime(self) // OK
   mutating func mutatingMethodOneParamLifetime(_: Int) -> NEImmortal { NEImmortal() }
 
-  @lifetime(borrow self) // OK
+  @_lifetime(&self) // OK
   mutating func mutatingMethodOneParamBorrow(_: Int) -> NEImmortal { NEImmortal() }
 }
 
@@ -159,40 +159,40 @@ struct NonescapableInoutInitializers: ~Escapable {
   init(c: inout C) { self.c = copy c } // OK
 }
 
-@lifetime(immortal)
+@_lifetime(immortal)
 func noParamImmortal() -> NEImmortal { NEImmortal() } // OK
 
-@lifetime(c)
+@_lifetime(c)
 func oneParamLifetime(c: C) -> NEImmortal { NEImmortal() }
 
 func oneParamBorrow(c: borrowing C) -> NEImmortal { NEImmortal() } // OK
 
-@lifetime(c)
+@_lifetime(c)
 func oneParamBorrowLifetime(c: borrowing C) -> NEImmortal { NEImmortal() } // OK
 
 func oneParamInout(c: inout C) -> NEImmortal { NEImmortal() } // OK
 
-@lifetime(c)
+@_lifetime(c)
 func oneParamInoutLifetime(c: inout C) -> NEImmortal { NEImmortal() } // OK
 
-@lifetime(c)
+@_lifetime(c)
 func twoParamsLifetime(c: C, _: Int) -> NEImmortal { NEImmortal() }
 
 func twoParamsBorrow(c: borrowing C, _: Int) -> NEImmortal { NEImmortal() } // OK
 
 func neParam(ne: NE) -> NE { ne } // OK
 
-@lifetime(ne) // OK
+@_lifetime(ne) // OK
 func neParamLifetime(ne: NE) -> NE { ne }
 
 func neParamBorrow(ne: borrowing NE) -> NE { copy ne } // OK
 
-@lifetime(ne) // OK
+@_lifetime(ne) // OK
 func neParamBorrowLifetime(ne: borrowing NE) -> NE { copy ne }
 
 func neParamConsume(ne: consuming NE) -> NE { ne } // OK
 
-@lifetime(ne) // OK
+@_lifetime(ne) // OK
 func neParamConsumeLifetime(ne: consuming NE) -> NE { ne }
 
 func neTwoParam(ne: NE, _:Int) -> NE { ne } // OK
@@ -234,7 +234,7 @@ struct Accessors {
 struct NonescapableSelfAccessors: ~Escapable {
   var ne: NE
 
-  @lifetime(immortal)
+  @_lifetime(immortal)
   init() {
     ne = NE()
   }
@@ -254,79 +254,79 @@ struct NonescapableSelfAccessors: ~Escapable {
       yield ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &ne
     }
   }
 
   var neComputedLifetime: NE {
-    @lifetime(self) // OK
+    @_lifetime(self) // OK
     get {
       ne
     }
 
-    @lifetime(self) // OK
+    @_lifetime(self: newValue) // OK
     set {
       ne = newValue
     }
   }
 
   var neYieldedLifetime: NE {
-    @lifetime(self) // OK
+    @_lifetime(self) // OK
     _read {
       yield ne
     }
 
-    @lifetime(self) // OK
+    @_lifetime(self) // OK
     _modify {
       yield &ne
     }
   }
 
   var neComputedCopy: NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     get {
       ne
     }
 
-    @lifetime(copy self)
+    @_lifetime(self: copy newValue)
     set {
       ne = newValue
     }
   }
 
   var neYieldedCopy: NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield ne
     }
 
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _modify {
       yield &ne
     }
   }
 
   var neComputedBorrow: NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     get {
       ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(self: borrow newValue)
     set {
       ne = newValue
     }
   }
 
   var neYieldedBorrow: NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     _read {
       yield ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &ne
     }
@@ -351,79 +351,79 @@ struct NoncopyableSelfAccessors: ~Copyable & ~Escapable {
       yield ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &ne
     }
   }
 
   var neComputedLifetime: NE {
-    @lifetime(self) // OK
+    @_lifetime(self) // OK
     get {
       ne
     }
 
-    @lifetime(self) // OK
+    @_lifetime(self: newValue) // OK
     set {
       ne = newValue
     }
   }
 
   var neYieldedLifetime: NE {
-    @lifetime(self) // OK
+    @_lifetime(self) // OK
     _read {
       yield ne
     }
 
-    @lifetime(self) // OK
+    @_lifetime(self) // OK
     _modify {
       yield &ne
     }
   }
 
   var neComputedCopy: NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     get {
       ne
     }
 
-    @lifetime(copy self)
+    @_lifetime(self: copy self)
     set {
       ne = newValue
     }
   }
 
   var neYieldedCopy: NE {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield ne
     }
 
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _modify {
       yield &ne
     }
   }
 
   var neComputedBorrow: NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     get {
       ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(self: borrow newValue)
     set {
       ne = newValue
     }
   }
 
   var neYieldedBorrow: NE {
-    @lifetime(borrow self)
+    @_lifetime(borrow self)
     _read {
       yield ne
     }
 
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &ne
     }
@@ -437,18 +437,18 @@ struct NoncopyableSelfAccessors: ~Copyable & ~Escapable {
 struct NonEscapableMutableSelf: ~Escapable {
   mutating func mutatingMethodNoParam() {} // OK
 
-  @lifetime(self: self) // OK
+  @_lifetime(self: self) // OK
   mutating func mutatingMethodNoParamLifetime() {}
 
-  @lifetime(self: copy self) // OK
+  @_lifetime(self: copy self) // OK
   mutating func mutatingMethodNoParamCopy() {}
 
-  @lifetime(self: self) // OK
+  @_lifetime(self: self) // OK
   mutating func mutatingMethodOneParamLifetime(_: NE) {}
 
-  @lifetime(copy self) // OK
+  @_lifetime(self: copy self) // OK
   mutating func mutatingMethodOneParamCopy(_: NE) {}
 
-  @lifetime(borrow self)
+  @_lifetime(self: copy self) // OK
   mutating func mutatingMethodOneParamBorrow(_: NE) {}
 }
diff --git a/test/Sema/lifetime_depend_noattr.swift b/test/Sema/lifetime_depend_noattr.swift
index 72442716c5f9a..c7e6f9de05a68 100644
--- a/test/Sema/lifetime_depend_noattr.swift
+++ b/test/Sema/lifetime_depend_noattr.swift
@@ -1,8 +1,8 @@
 // RUN: %target-typecheck-verify-swift \
 // RUN:   -disable-availability-checking \
-// RUN:   -enable-experimental-feature LifetimeDependence
+// RUN:   -enable-experimental-feature Lifetimes
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 // These tests complement lifetime_depend_nofeature.swift. If you add a test here, add one there.
  
@@ -13,18 +13,18 @@
 struct EmptyNonEscapable: ~Escapable {} // OK - no dependence
 
 // Don't allow non-Escapable return values.
-func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@lifetime(borrow span)' or '@lifetime(copy span)'}}
+func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{cannot infer the lifetime dependence scope on a function with a ~Escapable parameter, specify '@_lifetime(borrow span)' or '@_lifetime(copy span)'}}
 
 func neInout(span: inout RawSpan) {} // OK - inferred
 
 struct S {
-  func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a method with a ~Escapable result requires '@lifetime(...)}}
+  func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a method with a ~Escapable result requires '@_lifetime(...)}}
 
   func neInout(span: inout RawSpan) {} // OK - inferred
 }
 
 class C {
-  func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a method with a ~Escapable result requires '@lifetime(...)'}}
+  func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a method with a ~Escapable result requires '@_lifetime(...)'}}
 
   func neInout(span: inout RawSpan) {} // OK - inferred
 }
diff --git a/test/Sema/lifetime_depend_nofeature.swift b/test/Sema/lifetime_depend_nofeature.swift
index 0b188d0b37e94..8ee667a8f1dbd 100644
--- a/test/Sema/lifetime_depend_nofeature.swift
+++ b/test/Sema/lifetime_depend_nofeature.swift
@@ -6,21 +6,45 @@
 // Check that functions that require lifetime dependence are prohibited without the flag.
 
 // Don't allow empty initialization.
-struct EmptyNonEscapable: ~Escapable {} // expected-error{{an implicit initializer with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'}}
+struct EmptyNonEscapable: ~Escapable {} // expected-error{{an implicit initializer cannot return a ~Escapable result}}
 
 // Don't allow non-Escapable return values.
-func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a function with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'}}
+func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a function cannot return a ~Escapable result}}
 
-func neInout(span: inout RawSpan) {} // expected-error{{a function with a ~Escapable 'inout' parameter requires '-enable-experimental-feature LifetimeDependence'}}
+func neInout(span: inout RawSpan) {} // DEFAULT OK
+
+func neInoutNEParam(span: inout RawSpan, _: RawSpan) {} // DEFAULT OK
 
 struct S {
-  func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a method with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'}}
+  func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a method cannot return a ~Escapable result}}
+
+  func neInout(span: inout RawSpan) {} // OK
+
+  func neInoutNEParam(span: inout RawSpan, _: RawSpan) {} // DEFAULT OK
 
-  func neInout(span: inout RawSpan) {} // expected-error{{a method with a ~Escapable 'inout' parameter requires '-enable-experimental-feature LifetimeDependence'}}
+  mutating func mutatingNEInout(span: inout RawSpan) {} // OK
+
+  mutating func mutatingNEInoutParam(span: inout RawSpan, _: RawSpan) {} // DEFAULT OK
 }
 
 class C {
-  func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a method with a ~Escapable result requires '-enable-experimental-feature LifetimeDependence'}}
+  func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a method cannot return a ~Escapable result}}
+
+  func neInout(span: inout RawSpan) {} // OK
+}
+
+extension MutableSpan {
+  func method() {} // OK
+
+  mutating func mutatingMethod() {} // DEFAULT OK
+
+  func neReturn(span: RawSpan) -> RawSpan { span } // expected-error{{a method cannot return a ~Escapable result}}
+
+  func neInout(span: inout RawSpan) {} // DEFAULT OK
+
+  mutating func mutatingNEInout(span: inout RawSpan) {} // DEFAULT OK
+}
 
-  func neInout(span: inout RawSpan) {} // expected-error{{a method with a ~Escapable 'inout' parameter requires '-enable-experimental-feature LifetimeDependence'}}
+extension Span {
+  mutating func mutate() {} // DEFAULT OK
 }
diff --git a/test/Sema/lifetime_dependence_functype.swift b/test/Sema/lifetime_dependence_functype.swift
index 4e0f2a70fd6b1..ee704ac9292ab 100644
--- a/test/Sema/lifetime_dependence_functype.swift
+++ b/test/Sema/lifetime_dependence_functype.swift
@@ -1,6 +1,6 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature LifetimeDependence
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature Lifetimes
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 struct NC: ~Copyable {
   var ne: NE {
@@ -13,23 +13,23 @@ struct NE: ~Escapable {
   init() {}
 }
 
-@lifetime(copy ne)
+@_lifetime(copy ne)
 func transfer(_ ne: NE) -> NE {
   ne
 }
 
-@lifetime(copy ne)
-func applyAnnotatedTransfer(ne: NE, @lifetime(0) transfer: (NE) -> NE) -> NE { // expected-error{{'@lifetime' attribute cannot be applied to this declaration}}
+@_lifetime(copy ne)
+func applyAnnotatedTransfer(ne: NE, @_lifetime(0) transfer: (NE) -> NE) -> NE { // expected-error{{'@_lifetime' attribute cannot be applied to this declaration}}
   transfer(ne)
 }
 
-@lifetime(copy ne)
+@_lifetime(copy ne)
 func applyTransfer(ne: NE, transfer: (NE) ->  NE) -> NE {
   transfer(ne)
 }
 
 func testTransfer(nc: consuming NC) {
-  let transferred = applyTransfer(ne: nc.ne, transfer: transfer) // expected-error{{does not conform to expected type 'Escapable'}} e/xpected-error{{cannot convert value of type '(NE) -> @lifetime(copy 0) NE' to expected argument type '(NE) -> NE'}}
+  let transferred = applyTransfer(ne: nc.ne, transfer: transfer) // expected-error{{does not conform to expected type 'Escapable'}} e/xpected-error{{cannot convert value of type '(NE) -> @_lifetime(copy 0) NE' to expected argument type '(NE) -> NE'}}
 
   _ = consume nc
   _ = transfer(transferred)
@@ -39,13 +39,13 @@ func borrow(_ nc: borrowing NC) -> NE {
   nc.ne
 }
 
-@lifetime(borrow nc)
+@_lifetime(borrow nc)
 func applyBorrow(nc: borrowing NC, borrow: (borrowing NC) -> NE) -> NE {
   borrow(nc)
 }
 
 func testBorrow(nc: consuming NC) {
-  let borrowed = applyBorrow(nc: nc, borrow: borrow) // expected-error{{does not conform to expected type 'Escapable'}} ex/pected-error{{cannot convert value of type '(borrowing NC) -> @lifetime(borrow 0) NE' to expected argument type '(borrowing NC) -> NE}}
+  let borrowed = applyBorrow(nc: nc, borrow: borrow) // expected-error{{does not conform to expected type 'Escapable'}} ex/pected-error{{cannot convert value of type '(borrowing NC) -> @_lifetime(borrow 0) NE' to expected argument type '(borrowing NC) -> NE}}
   _ = consume nc
   _ = transfer(borrowed)
 }
diff --git a/test/Sema/manualownership_attr.swift b/test/Sema/manualownership_attr.swift
new file mode 100644
index 0000000000000..be99aeb1ccd09
--- /dev/null
+++ b/test/Sema/manualownership_attr.swift
@@ -0,0 +1,14 @@
+// RUN: %target-typecheck-verify-swift \
+// RUN:    -enable-experimental-feature NoImplicitCopy \
+// RUN:    -enable-experimental-feature ManualOwnership
+
+// REQUIRES: swift_feature_ManualOwnership
+// REQUIRES: swift_feature_NoImplicitCopy
+
+class C {}
+
+@_manualOwnership
+func hello() -> (C, C) {
+  @_noImplicitCopy let x = C() // expected-error {{'@_noImplicitCopy' cannot be used with ManualOwnership}}
+  return (x, x)
+}
diff --git a/test/Sema/missing-import-typealias-swift6.swift b/test/Sema/missing-import-typealias-swift6.swift
index 5061d2f106300..9cc55582e756d 100644
--- a/test/Sema/missing-import-typealias-swift6.swift
+++ b/test/Sema/missing-import-typealias-swift6.swift
@@ -7,7 +7,7 @@
 // RUN: %target-swift-emit-module-interface(%t/Aliases.swiftinterface) %t/Aliases.swift -I %t
 // RUN: %target-swift-typecheck-module-from-interface(%t/Aliases.swiftinterface) -I %t
 
-// RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesNoImport.swift -enable-library-evolution -I %t -swift-version 6
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/UsesAliasesNoImport.swift -enable-library-evolution -I %t -swift-version 6
 
 // This test is a simplified version of missing-import-typealias.swift that
 // verifies errors are emitted instead of warnings in Swift 6.
diff --git a/test/Sema/missing-import-typealias.swift b/test/Sema/missing-import-typealias.swift
index 2860156817f80..bc55f2ec4230b 100644
--- a/test/Sema/missing-import-typealias.swift
+++ b/test/Sema/missing-import-typealias.swift
@@ -7,10 +7,10 @@
 // RUN: %target-swift-emit-module-interface(%t/Aliases.swiftinterface) %t/Aliases.swift -I %t
 // RUN: %target-swift-typecheck-module-from-interface(%t/Aliases.swiftinterface) -I %t
 
-// RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesNoImport.swift -enable-library-evolution -I %t
-// RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesImplementationOnlyImport.swift -enable-library-evolution -I %t
-// RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesSPIOnlyImport.swift -enable-library-evolution -I %t -experimental-spi-only-imports
-// RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesWithImport.swift -enable-library-evolution -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/UsesAliasesNoImport.swift -enable-library-evolution -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/UsesAliasesImplementationOnlyImport.swift -enable-library-evolution -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/UsesAliasesSPIOnlyImport.swift -enable-library-evolution -I %t -experimental-spi-only-imports
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/UsesAliasesWithImport.swift -enable-library-evolution -I %t
 
 /// With library evolution disabled UsesAliasesNoImport.swift should compile without diagnostics.
 // RUN: %target-swift-frontend -typecheck %t/UsesAliasesNoImport.swift -I %t | %FileCheck %t/UsesAliasesNoImport.swift --check-prefix=CHECK-NON-RESILIENT --allow-empty
diff --git a/test/Sema/moveonly_sendable.swift b/test/Sema/moveonly_sendable.swift
index 0ea0334be56c9..f3ec4ace7caf7 100644
--- a/test/Sema/moveonly_sendable.swift
+++ b/test/Sema/moveonly_sendable.swift
@@ -65,12 +65,12 @@ func caller() async {
 // now make sure you can't form a Sendable existential from a move-only type.
 
 struct RefPair: Sendable, ~Copyable {
-  var left: Ref // expected-warning {{stored property 'left' of 'Sendable'-conforming struct 'RefPair' has non-sendable type 'Ref'}}
-  var right: Ref  // expected-warning {{stored property 'right' of 'Sendable'-conforming struct 'RefPair' has non-sendable type 'Ref'}}
+  var left: Ref // expected-warning {{stored property 'left' of 'Sendable'-conforming struct 'RefPair' has non-Sendable type 'Ref'}}
+  var right: Ref  // expected-warning {{stored property 'right' of 'Sendable'-conforming struct 'RefPair' has non-Sendable type 'Ref'}}
 }
 
 enum MaybeRef: Sendable, ~Copyable {
-  case ref(Ref) // expected-warning {{associated value 'ref' of 'Sendable'-conforming enum 'MaybeRef' has non-sendable type 'Ref'}}
+  case ref(Ref) // expected-warning {{associated value 'ref' of 'Sendable'-conforming enum 'MaybeRef' has non-Sendable type 'Ref'}}
   case null
 }
 
@@ -80,7 +80,7 @@ enum OK_NoncopyableOption<T: Sendable> : Sendable, ~Copyable {
 }
 
 enum Wrong_NoncopyableOption<T> : Sendable, ~Copyable { // expected-note {{consider making generic parameter 'T' conform to the 'Sendable' protocol}}
-  case some(T) // expected-warning {{associated value 'some' of 'Sendable'-conforming generic enum 'Wrong_NoncopyableOption' has non-sendable type 'T'}}
+  case some(T) // expected-warning {{associated value 'some' of 'Sendable'-conforming generic enum 'Wrong_NoncopyableOption' has non-Sendable type 'T'}}
   case none
 }
 
diff --git a/test/Sema/objc_attr_fixit_nsobject.swift b/test/Sema/objc_attr_fixit_nsobject.swift
index 55342de798b03..c0735d6078826 100644
--- a/test/Sema/objc_attr_fixit_nsobject.swift
+++ b/test/Sema/objc_attr_fixit_nsobject.swift
@@ -8,10 +8,10 @@ import Foundation
 class NonObjCBase {}
 protocol NonObjCProto {}
 
-@objc class AddSuper {} // expected-error {{only classes that inherit from NSObject can be declared @objc}} {{1-7=}}
+@objc class AddSuper {} // expected-error {{only classes that inherit from NSObject can be declared '@objc'}} {{1-7=}}
 // expected-note@-1 {{inherit from 'NSObject' to silence this error}} {{21-21=: NSObject}}
 
-@objc class InsertSuper: NonObjCProto {} // expected-error {{only classes that inherit from NSObject can be declared @objc}} {{1-7=}}
+@objc class InsertSuper: NonObjCProto {} // expected-error {{only classes that inherit from NSObject can be declared '@objc'}} {{1-7=}}
 // expected-note@-1 {{inherit from 'NSObject' to silence this error}} {{26-26=NSObject, }}
 
-@objc class NoNote: NonObjCBase {} // expected-error {{only classes that inherit from NSObject can be declared @objc}} {{1-7=}}
+@objc class NoNote: NonObjCBase {} // expected-error {{only classes that inherit from NSObject can be declared '@objc'}} {{1-7=}}
diff --git a/test/Sema/objc_attr_requires_module_1.swift b/test/Sema/objc_attr_requires_module_1.swift
index 586b7a267ff48..1eefa56072ae6 100644
--- a/test/Sema/objc_attr_requires_module_1.swift
+++ b/test/Sema/objc_attr_requires_module_1.swift
@@ -5,7 +5,7 @@
 // appeared before any top-level expressions. The _1 and _2 variants of
 // this test cover both cases.
 
-@objc class Foo {} // expected-error {{@objc attribute used without importing module 'Foundation'}} expected-error {{only classes that inherit from NSObject can be declared @objc}} {{1-7=}}
+@objc class Foo {} // expected-error {{@objc attribute used without importing module 'Foundation'}} expected-error {{only classes that inherit from NSObject can be declared '@objc'}} {{1-7=}}
 // expected-note@-1 {{inherit from 'NSObject' to silence this error}} {{16-16=: NSObject}}
 
 #if false
diff --git a/test/Sema/objc_attr_requires_module_2.swift b/test/Sema/objc_attr_requires_module_2.swift
index c76fc5e5eae51..a944a5c0591a5 100644
--- a/test/Sema/objc_attr_requires_module_2.swift
+++ b/test/Sema/objc_attr_requires_module_2.swift
@@ -3,5 +3,5 @@
 class Foo {}
 _ = Foo()
 
-@objc class NSFoo {} // expected-error {{@objc attribute used without importing module 'Foundation'}} expected-error {{only classes that inherit from NSObject can be declared @objc}} {{1-7=}}
+@objc class NSFoo {} // expected-error {{@objc attribute used without importing module 'Foundation'}} expected-error {{only classes that inherit from NSObject can be declared '@objc'}} {{1-7=}}
 // expected-note@-1 {{inherit from 'NSObject' to silence this error}} {{18-18=: NSObject}}
diff --git a/test/Sema/objc_property_wrappers.swift b/test/Sema/objc_property_wrappers.swift
index 7bb0c5b4df4f1..480637cccf8ee 100644
--- a/test/Sema/objc_property_wrappers.swift
+++ b/test/Sema/objc_property_wrappers.swift
@@ -28,8 +28,8 @@ public class WrapperObjcClass: NSObject {
 
 class GenericClassCase {
     @objc
-    func foo(@WrapperGenericClass _ ref: Int) throws {} // expected-error {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
-    // expected-note@-1 {{classes not annotated with @objc cannot be represented in Objective-C}}
+    func foo(@WrapperGenericClass _ ref: Int) throws {} // expected-error {{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
+    // expected-note@-1 {{classes not annotated with '@objc' cannot be represented in Objective-C}}
 }
 
 @propertyWrapper
@@ -51,7 +51,7 @@ public class WrapperGenericClass<Element> {
 
 class StructCase {
     @objc
-    func foo(@WrapperStruct _ ref: Int) throws {} // expected-error {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+    func foo(@WrapperStruct _ ref: Int) throws {} // expected-error {{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
     // expected-note@-1 {{Swift structs cannot be represented in Objective-C}}
 }
 
@@ -74,7 +74,7 @@ public struct WrapperStruct {
 
 class EnumCase {
     @objc
-    func foo(@WrapperEnum _ ref: Int) throws {} // expected-error {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+    func foo(@WrapperEnum _ ref: Int) throws {} // expected-error {{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
     // expected-note@-1 {{non-'@objc' enums cannot be represented in Objective-C}}
 }
 
diff --git a/test/Sema/package-import-conforming-types.swift b/test/Sema/package-import-conforming-types.swift
index 9ae7fd2879c30..d7b6ed0c6201c 100644
--- a/test/Sema/package-import-conforming-types.swift
+++ b/test/Sema/package-import-conforming-types.swift
@@ -8,9 +8,9 @@
 // RUN:  %S/Inputs/implementation-only-import-in-decls-helper.swift -I %t \
 // RUN:  -enable-library-evolution -swift-version 5
 
-// RUN: %target-typecheck-verify-swift -I %t \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t \
 // RUN:  -swift-version 5 -package-name pkg -enable-library-evolution
-// RUN: %target-typecheck-verify-swift -I %t \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t \
 // RUN:  -swift-version 5 -package-name pkg
 
 package import BADLibrary // expected-note 8 {{protocol 'BadProto' imported as 'package' from 'BADLibrary' here}}
diff --git a/test/Sema/placeholder_type.swift b/test/Sema/placeholder_type.swift
index eae6511cb31fa..99fc6930f87a8 100644
--- a/test/Sema/placeholder_type.swift
+++ b/test/Sema/placeholder_type.swift
@@ -10,11 +10,10 @@ let dict2: [Character: _] = ["h": 0]
 
 let arr = [_](repeating: "hi", count: 3)
 
-func foo(_ arr: [_] = [0]) {} // expected-error {{type placeholder may not appear in top-level parameter}}
-// expected-note@-1 {{replace the placeholder with the inferred type 'Int'}}
+func foo(_ arr: [_] = [0]) {} // expected-error {{type placeholder not allowed here}}
 
 let foo = _.foo // expected-error {{type placeholder not allowed here}}
-let zero: _ = .zero // expected-error {{cannot infer contextual base in reference to member 'zero'}}
+let zero: _ = .zero // expected-error {{reference to member 'zero' cannot be resolved without a contextual type}}
 
 struct S<T> {
     var x: T
@@ -54,7 +53,7 @@ let _: [String: _] = dictionary(ofType: [_: Int].self)
 let _: [_: _] = dictionary(ofType: [String: Int].self)
 let _: [String: Int] = dictionary(ofType: _.self) // expected-error {{type placeholder not allowed here}}
 
-let _: @convention(c) _ = { 0 } // expected-error {{@convention attribute only applies to function types}}
+let _: @convention(c) _ = { 0 } // expected-error {{'@convention' only applies to function types}}
 let _: @convention(c) (_) -> _ = { (x: Double) in 0 }
 let _: @convention(c) (_) -> Int = { (x: Double) in 0 }
 
@@ -78,33 +77,25 @@ where T: ExpressibleByIntegerLiteral, U: ExpressibleByIntegerLiteral {
 }
 
 extension Bar {
-  func frobnicate2() -> Bar<_, _> { // expected-error {{type placeholder may not appear in function return type}}
-    // expected-note@-1 {{replace the placeholder with the inferred type 'T'}}
-    // expected-note@-2 {{replace the placeholder with the inferred type 'U'}}
+  func frobnicate2() -> Bar<_, _> { // expected-error {{type placeholder not allowed here}}
     return Bar(t: 42, u: 42)
   }
   func frobnicate3() -> Bar {
     return Bar<_, _>(t: 42, u: 42)
   }
-  func frobnicate4() -> Bar<_, _> { // expected-error {{type placeholder may not appear in function return type}}
-    // expected-note@-1 {{replace the placeholder with the inferred type 'Int'}}
-    // expected-note@-2 {{replace the placeholder with the inferred type 'Int'}}
+  func frobnicate4() -> Bar<_, _> { // expected-error {{type placeholder not allowed here}}
     return Bar<_, _>(t: 42, u: 42)
   }
-  func frobnicate5() -> Bar<_, U> { // expected-error {{type placeholder may not appear in function return type}}
-    // expected-note@-1 {{replace the placeholder with the inferred type 'T'}}
+  func frobnicate5() -> Bar<_, U> { // expected-error {{type placeholder not allowed here}}
     return Bar(t: 42, u: 42)
   }
   func frobnicate6() -> Bar {
     return Bar<_, U>(t: 42, u: 42)
   }
-  func frobnicate7() -> Bar<_, _> { // expected-error {{type placeholder may not appear in function return type}}
-    // expected-note@-1 {{replace the placeholder with the inferred type 'Int'}}
-    // expected-note@-2 {{replace the placeholder with the inferred type 'U'}}
+  func frobnicate7() -> Bar<_, _> { // expected-error {{type placeholder not allowed here}}
     return Bar<_, U>(t: 42, u: 42)
   }
-  func frobnicate8() -> Bar<_, U> { // expected-error {{type placeholder may not appear in function return type}}
-    // expected-note@-1 {{replace the placeholder with the inferred type 'Int'}}
+  func frobnicate8() -> Bar<_, U> { // expected-error {{type placeholder not allowed here}}
     return Bar<_, _>(t: 42, u: 42)
   }
 }
@@ -244,11 +235,11 @@ let _: SetFailureType<Int, String> = Just<Int>().setFailureType(to: _.self).setF
 // diagnostic.
 func mismatchedDefault<T>(_ x: [_] = [String: T]()) {} // expected-error {{type placeholder not allowed here}}
 
-func mismatchedReturnTypes() -> _ { // expected-error {{type placeholder may not appear in function return type}}
+func mismatchedReturnTypes() -> _ { // expected-error {{type placeholder not allowed here}}
   if true {
-    return "" // expected-note@-2 {{replace the placeholder with the inferred type 'String'}}
+    return ""
   } else {
-    return 0.5 // expected-note@-4 {{replace the placeholder with the inferred type 'Double'}}
+    return 0.5
   }
 }
 
@@ -257,12 +248,12 @@ func mismatchedReturnTypes() -> _ { // expected-error {{type placeholder may not
 @available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
 func opaque() -> some _ { // expected-error {{type placeholder not allowed here}}
   return Just<Int>().setFailureType(to: _.self)
+  // expected-error@-1 {{type placeholder not allowed here}}
 }
 
 enum EnumWithPlaceholders {
-  case topLevelPlaceholder(x: _) // expected-error {{type placeholder may not appear in top-level parameter}}
-  case placeholderWithDefault(x: _ = 5) // expected-error {{type placeholder may not appear in top-level parameter}}
-  // expected-note@-1 {{replace the placeholder with the inferred type 'Int'}}
+  case topLevelPlaceholder(x: _) // expected-error {{type placeholder not allowed here}}
+  case placeholderWithDefault(x: _ = 5) // expected-error {{type placeholder not allowed here}}
 }
 
 func deferredInit(_ c: Bool) {
@@ -290,3 +281,70 @@ do {
     _ = X(content: <#T##() -> _#>) // expected-error {{editor placeholder in source file}}
   }
 }
+
+// Make sure we reject placeholders here.
+protocol TestPlaceholderRequirement {
+  func foo(_:_) // expected-error {{type placeholder not allowed here}}
+  func bar() -> _ // expected-error {{type placeholder not allowed here}}
+  func baz() -> [_] // expected-error {{type placeholder not allowed here}}
+  func qux(_: [_]) // expected-error {{type placeholder not allowed here}}
+
+  subscript(_: _) -> Void { get } // expected-error {{type placeholder not allowed here}}
+  subscript() -> _ { get } // expected-error {{type placeholder not allowed here}}
+}
+
+func testPlaceholderFn1(_:_) {} // expected-error {{type placeholder not allowed here}}
+func testPlaceholderFn2() -> _ {} // expected-error {{type placeholder not allowed here}}
+
+var testPlaceholderComputed1: _ { 0 } // expected-error {{type placeholder not allowed here}}
+var testPlaceholderComputed2: [_] { [0] } // expected-error {{type placeholder not allowed here}}
+
+struct TestPlaceholderSubscript {
+  subscript(_: _) -> Void { () } // expected-error {{type placeholder not allowed here}}
+  subscript(_: [_]) -> Void { () } // expected-error {{type placeholder not allowed here}}
+  subscript() -> _ { () } // expected-error {{type placeholder not allowed here}}
+  subscript() -> [_] { [0] } // expected-error {{type placeholder not allowed here}}
+}
+
+enum TestPlaceholderInEnumElement {
+  case a(_) // expected-error {{type placeholder not allowed here}}
+  case b([_]) // expected-error {{type placeholder not allowed here}}
+}
+
+@freestanding(expression) macro testPlaceholderMacro(_ x: _) -> String = #file
+// expected-error@-1 {{type placeholder not allowed here}}
+
+@freestanding(expression) macro testPlaceholderMacro(_ x: [_]) -> String = #file
+// expected-error@-1 {{type placeholder not allowed here}}
+
+@freestanding(expression) macro testPlaceholderMacro() -> _ = #file
+// expected-error@-1 {{type placeholder not allowed here}}
+
+// Make sure we can use decls with placeholders in their interface type.
+func usePlaceholderDecls(
+  _ fromProto: some TestPlaceholderRequirement, _ hasSubscript: TestPlaceholderSubscript
+) {
+  _ = optInt
+
+  _ = testPlaceholderComputed1
+  _ = testPlaceholderComputed2
+
+  fromProto.foo(0)
+  _ = fromProto.bar()
+  _ = fromProto.baz()
+  fromProto.qux([])
+  fromProto[0]
+
+  _ = hasSubscript[0]
+
+  _ = TestPlaceholderInEnumElement.a(0)
+  _ = TestPlaceholderInEnumElement.b([])
+
+  // There are marked invalid so get removed from the overload set.
+  // FIXME: We ought to turn them into holes instead
+  _ = #testPlaceholderMacro(0) // expected-error {{no macro named 'testPlaceholderMacro'}}
+  _ = #testPlaceholderMacro([]) // expected-error {{no macro named 'testPlaceholderMacro'}}
+
+  _ = testPlaceholderFn1(0)
+  _ = testPlaceholderFn2()
+}
diff --git a/test/Sema/pound_diagnostics.swift b/test/Sema/pound_diagnostics.swift
index c4cf8d435bc3c..bf1462d608292 100644
--- a/test/Sema/pound_diagnostics.swift
+++ b/test/Sema/pound_diagnostics.swift
@@ -82,3 +82,6 @@ protocol MyProtocol {
          """) // expected-warning @-2 {{warnings support multi-line string literals}}
 
 #warning(#"warnings support \(custom string delimiters)"#) // expected-warning {{warnings support \\(custom string delimiters)}}
+
+#warning // expected-error {{#warning directive requires parentheses}} {{9-9=("<#message#>")}}
+("message") // expected-warning {{string literal is unused}}
diff --git a/test/Sema/public-module-name.swift b/test/Sema/public-module-name.swift
index 9021123f933ff..1545c99cb0d21 100644
--- a/test/Sema/public-module-name.swift
+++ b/test/Sema/public-module-name.swift
@@ -30,13 +30,13 @@
 // RUN: cat %t/LibCore.swiftinterface | %FileCheck --check-prefix=CHECK-FLAG %s
 // RUN: cat %t/LibMiddle.swiftinterface | %FileCheck --check-prefix=CHECK-FLAG %s
 // CHECK-FLAG: swift-module-flags-ignorable:
-// CHECK-SAME-FLAG: -public-module-name Lib
+// CHECK-FLAG-SAME: -public-module-name Lib
 
 /// Build clients against binary swiftmodules.
 /// First errors in files, then diagnostics in other files.
 // RUN: %target-swift-frontend -typecheck %t/ClientPublic.swift -o %t -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
-// RUN:   -verify
+// RUN:   -verify -verify-ignore-unrelated
 // RUN: not %target-swift-frontend -typecheck %t/ClientPublic.swift -o %t -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
 // RUN:   -diagnostic-style llvm \
@@ -44,7 +44,7 @@
 
 // RUN: %target-swift-frontend -typecheck %t/ClientMiddle.swift -o %t -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
-// RUN:   -verify
+// RUN:   -verify -verify-ignore-unrelated
 // RUN: not %target-swift-frontend -typecheck %t/ClientMiddle.swift -o %t -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
 // RUN:   -diagnostic-style llvm \
@@ -53,13 +53,13 @@
 /// Test more diagnostics referencing modules.
 // RUN: %target-swift-frontend -typecheck %t/ClientAccessLevelOnImports.swift -o %t -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
-// RUN:   -verify
+// RUN:   -verify -verify-ignore-unrelated
 
 /// Build client against textual swiftinterfaces.
 // RUN: rm %t/LibCore.swiftmodule %t/LibMiddle.swiftmodule %t/Lib.swiftmodule
 // RUN: %target-swift-frontend -typecheck %t/ClientPublic.swift -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
-// RUN:   -verify
+// RUN:   -verify -verify-ignore-unrelated
 // RUN: not %target-swift-frontend -typecheck %t/ClientPublic.swift -o %t -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
 // RUN:   -diagnostic-style llvm \
@@ -67,7 +67,7 @@
 
 // RUN: %target-swift-frontend -typecheck %t/ClientMiddle.swift -o %t -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
-// RUN:   -verify
+// RUN:   -verify -verify-ignore-unrelated
 // RUN: not %target-swift-frontend -typecheck %t/ClientMiddle.swift -o %t -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
 // RUN:   -diagnostic-style llvm \
@@ -75,7 +75,7 @@
 
 // RUN: %target-swift-frontend -typecheck %t/ClientAccessLevelOnImports.swift -o %t -I %t \
 // RUN:   -enable-library-evolution -swift-version 6 \
-// RUN:   -verify
+// RUN:   -verify -verify-ignore-unrelated
 
 //--- LibCore.swift
 public func ambiguous() {}
diff --git a/test/Sema/raw_layout.swift b/test/Sema/raw_layout.swift
index a0a4f5a1334ee..830e4611ef9b7 100644
--- a/test/Sema/raw_layout.swift
+++ b/test/Sema/raw_layout.swift
@@ -2,19 +2,19 @@
 
 // REQUIRES: swift_feature_RawLayout
 
-@_rawLayout(size: 4, alignment: 4) // expected-error{{type with @_rawLayout cannot be copied and must be declared ~Copyable}}
+@_rawLayout(size: 4, alignment: 4) // expected-error{{type with '@_rawLayout' cannot be copied and must be declared ~Copyable}}
 struct ImproperlyCopyable {}
 
 @_rawLayout(size: 4, alignment: 3) // expected-error{{alignment value must be a power of two}}
 struct InvalidAlignment: ~Copyable {}
 
-@_rawLayout(size: 4, alignment: 4) // expected-error{{type with @_rawLayout cannot have stored properties}}
+@_rawLayout(size: 4, alignment: 4) // expected-error{{type with '@_rawLayout' cannot have stored properties}}
 struct HasStoredProperty: ~Copyable { var x: Int }
 
-@_rawLayout(size: 4, alignment: 4) // expected-error{{type with @_rawLayout cannot have stored properties}}
+@_rawLayout(size: 4, alignment: 4) // expected-error{{type with '@_rawLayout' cannot have stored properties}}
 struct HasLazyStoredProperty: ~Copyable { lazy var x: Int = 42 }
 
-@_rawLayout(size: 4, alignment: 4) // expected-error{{type with @_rawLayout cannot have stored properties}}
+@_rawLayout(size: 4, alignment: 4) // expected-error{{type with '@_rawLayout' cannot have stored properties}}
 struct HasObservedStoredProperty: ~Copyable { var x: Int { didSet { } } }
 
 @propertyWrapper
@@ -22,7 +22,7 @@ struct Wrapper<T> {
     var wrappedValue: T { fatalError() }
 }
 
-@_rawLayout(size: 4, alignment: 4) // expected-error{{type with @_rawLayout cannot have stored properties}}
+@_rawLayout(size: 4, alignment: 4) // expected-error{{type with '@_rawLayout' cannot have stored properties}}
 struct HasWrappedStoredProperty: ~Copyable { @Wrapper var x: Int }
 
 @_rawLayout(like: T) // expected-error{{cannot find type 'T' in scope}}
@@ -45,5 +45,5 @@ struct Butt {
     var propertyWithStoredLayout: ()
 }
 
-@_rawLayout(size: 4, alignment: 4) @_alignment(16) // expected-error{{type with @_rawLayout cannot also have an @_alignment attribute}}
+@_rawLayout(size: 4, alignment: 4) @_alignment(16) // expected-error{{type with '@_rawLayout' cannot also have an '@_alignment' attribute}}
 struct RawLayoutAndAlignment: ~Copyable {}
diff --git a/test/Sema/raw_layout_parse.swift b/test/Sema/raw_layout_parse.swift
index a604b5ad47a62..7d7ce82d5283a 100644
--- a/test/Sema/raw_layout_parse.swift
+++ b/test/Sema/raw_layout_parse.swift
@@ -20,12 +20,12 @@ struct SmallVectorBuf<T>: ~Copyable {}
 @_rawLayout // expected-error{{expected '('}}
 struct NoLayoutSpecified: ~Copyable {}
 
-@_rawLayout() // expected-error{{expected 'size', 'like', or 'likeArrayOf' argument to @_rawLayout attribute}}
+@_rawLayout() // expected-error{{expected 'size', 'like', or 'likeArrayOf' argument to '@_rawLayout'}}
 struct NoParamsSpecified: ~Copyable {}
 
-@_rawLayout(size: 4) // expected-error{{expected alignment argument after size argument in @_rawLayout attribute}}
+@_rawLayout(size: 4) // expected-error{{expected alignment argument after size argument in '@_rawLayout'}}
 struct SizeWithoutAlignment: ~Copyable {}
 
-@_rawLayout(likeArrayOf: Optional<Int>) // expected-error{{expected count argument after likeArrayOf argument in @_rawLayout attribute}}
+@_rawLayout(likeArrayOf: Optional<Int>) // expected-error{{expected count argument after likeArrayOf argument in '@_rawLayout'}}
 struct ArrayWithoutSize: ~Copyable {}
 
diff --git a/test/Sema/raw_layout_sendable.swift b/test/Sema/raw_layout_sendable.swift
index b596111e09c43..0eaba40389451 100644
--- a/test/Sema/raw_layout_sendable.swift
+++ b/test/Sema/raw_layout_sendable.swift
@@ -14,11 +14,11 @@ struct NotAutomaticallySendable: ~Copyable {} // expected-note{{}}
 func testNotAutomaticallySendable() {
     let s = NotAutomaticallySendable()
 
-    checkSendable { _ = s } // expected-warning{{capture of 's' with non-sendable type 'NotAutomaticallySendable'}}
+    checkSendable { _ = s } // expected-warning{{capture of 's' with non-Sendable type 'NotAutomaticallySendable'}}
 }
 
 @_rawLayout(size: 4, alignment: 4)
-struct UnuncheckedSendable: ~Copyable, Sendable {} // expected-warning{{@_rawLayout does not conform to the 'Sendable' protocol}}
+struct UnuncheckedSendable: ~Copyable, Sendable {} // expected-warning{{'@_rawLayout' does not conform to the 'Sendable' protocol}}
 
 func testUnuncheckedSendable() {
     let s = UnuncheckedSendable()
diff --git a/test/Sema/rdar153096639.swift b/test/Sema/rdar153096639.swift
new file mode 100644
index 0000000000000..a5960ccb544c5
--- /dev/null
+++ b/test/Sema/rdar153096639.swift
@@ -0,0 +1,18 @@
+// RUN: %target-typecheck-verify-swift
+
+// Make sure we don't run into a request cycle for the below use of 'CodingKeys'
+// in an `init(from:)` signature.
+
+protocol P {
+  associatedtype X
+}
+
+struct S: Codable {
+  var foo: String?
+
+  enum CodingKeys: CodingKey {
+    case foo
+  }
+
+  init<T: P>(from: T) where T.X == CodingKeys {}
+}
diff --git a/test/Sema/restricted-imports-priorities.swift b/test/Sema/restricted-imports-priorities.swift
index f24a41690503a..d89360d48121b 100644
--- a/test/Sema/restricted-imports-priorities.swift
+++ b/test/Sema/restricted-imports-priorities.swift
@@ -15,22 +15,22 @@
 // RUN:   -module-name LibC -emit-module-path %t/LibC.swiftmodule \
 // RUN:   -swift-version 5 -enable-library-evolution -I %t
 
-// RUN: %target-swift-frontend -typecheck %t/TwoIOI.swift -I %t -verify \
+// RUN: %target-swift-frontend -typecheck %t/TwoIOI.swift -I %t -verify -verify-ignore-unrelated \
 // RUN:   -swift-version 5 -enable-library-evolution \
 // RUN:   -experimental-spi-only-imports -verify
-// RUN: %target-swift-frontend -typecheck %t/SPIOnlyAndIOI1.swift -I %t -verify \
+// RUN: %target-swift-frontend -typecheck %t/SPIOnlyAndIOI1.swift -I %t -verify -verify-ignore-unrelated \
 // RUN:   -swift-version 5 -enable-library-evolution \
 // RUN:   -experimental-spi-only-imports -verify
-// RUN: %target-swift-frontend -typecheck %t/SPIOnlyAndIOI2.swift -I %t -verify \
+// RUN: %target-swift-frontend -typecheck %t/SPIOnlyAndIOI2.swift -I %t -verify -verify-ignore-unrelated \
 // RUN:   -swift-version 5 -enable-library-evolution \
 // RUN:   -experimental-spi-only-imports -verify
-// RUN: %target-swift-frontend -typecheck %t/TwoSPIOnly.swift -I %t -verify \
+// RUN: %target-swift-frontend -typecheck %t/TwoSPIOnly.swift -I %t -verify -verify-ignore-unrelated \
 // RUN:   -swift-version 5 -enable-library-evolution \
 // RUN:   -experimental-spi-only-imports -verify
-// RUN: %target-swift-frontend -typecheck %t/OneSPIOnly1.swift -I %t -verify \
+// RUN: %target-swift-frontend -typecheck %t/OneSPIOnly1.swift -I %t -verify -verify-ignore-unrelated \
 // RUN:   -swift-version 5 -enable-library-evolution \
 // RUN:   -experimental-spi-only-imports -verify
-// RUN: %target-swift-frontend -typecheck %t/OneSPIOnly2.swift -I %t -verify \
+// RUN: %target-swift-frontend -typecheck %t/OneSPIOnly2.swift -I %t -verify -verify-ignore-unrelated \
 // RUN:   -swift-version 5 -enable-library-evolution \
 // RUN:   -experimental-spi-only-imports -verify
 
diff --git a/test/Sema/sending.swift b/test/Sema/sending.swift
index a9718e6373487..8887f23f110ab 100644
--- a/test/Sema/sending.swift
+++ b/test/Sema/sending.swift
@@ -1,7 +1,6 @@
-// RUN: %target-typecheck-verify-swift -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation -enable-experimental-feature SendingArgsAndResults
+// RUN: %target-typecheck-verify-swift -strict-concurrency=complete -enable-experimental-feature SendingArgsAndResults
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_RegionBasedIsolation
 // REQUIRES: swift_feature_SendingArgsAndResults
 
 // README: This test makes sure that we error when sending is placed in the
diff --git a/test/Sema/struct_equatable_hashable.swift b/test/Sema/struct_equatable_hashable.swift
index bb6f82c5ea28f..ae48bc536048c 100644
--- a/test/Sema/struct_equatable_hashable.swift
+++ b/test/Sema/struct_equatable_hashable.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -primary-file %s %S/Inputs/struct_equatable_hashable_other.swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -primary-file %s %S/Inputs/struct_equatable_hashable_other.swift -verify-ignore-unknown -swift-version 4
 
 var hasher = Hasher()
 
diff --git a/test/Sema/swiftsettings.swift b/test/Sema/swiftsettings.swift
deleted file mode 100644
index fa230432358a0..0000000000000
--- a/test/Sema/swiftsettings.swift
+++ /dev/null
@@ -1,20 +0,0 @@
-// RUN: %target-swift-frontend -enable-experimental-feature SwiftSettings -enable-experimental-feature Macros -c -swift-version 6 -disable-availability-checking -verify -Xllvm -swift-settings-allow-duplicates %s
-
-// REQUIRES: asserts
-// REQUIRES: concurrency
-// REQUIRES: swift_feature_Macros
-// REQUIRES: swift_feature_SwiftSettings
-
-actor MyActor {}
-
-#SwiftSettings(.defaultIsolation(MainActor.self))
-#SwiftSettings(.defaultIsolation(nil))
-#SwiftSettings(.defaultIsolation(MyActor.self)) // expected-error {{Unrecognized setting passed to #SwiftSettings}}
-#SwiftSettings(.defaultIsolation(1)) // expected-error {{Unrecognized setting passed to #SwiftSettings}}
-// expected-error @-1 {{cannot convert value of type 'Int' to expected argument type 'any Actor.Type'}}
-#SwiftSettings(2) // expected-error {{Unrecognized setting passed to #SwiftSettings}}
-// expected-error @-1 {{cannot convert value of type 'Int' to expected argument type 'SwiftSetting'}}
-
-#SwiftSettings(.defaultIsolation(MainActor.self),
-               .defaultIsolation(nil))
-
diff --git a/test/Sema/swiftsettings_duplicates.swift b/test/Sema/swiftsettings_duplicates.swift
deleted file mode 100644
index d55d251564905..0000000000000
--- a/test/Sema/swiftsettings_duplicates.swift
+++ /dev/null
@@ -1,24 +0,0 @@
-// RUN: %target-swift-frontend -enable-experimental-feature SwiftSettings -enable-experimental-feature Macros -c -swift-version 6 -disable-availability-checking -verify %s
-
-// REQUIRES: asserts
-// REQUIRES: concurrency
-// REQUIRES: swift_feature_Macros
-// REQUIRES: swift_feature_SwiftSettings
-
-// This test specifically tests the behavior of #SwiftSettings when we find
-// multiple instances of the same setting.
-
-actor MyActor {}
-
-#SwiftSettings(.defaultIsolation(MainActor.self), // expected-note 6 {{setting originally passed here}}
-               .defaultIsolation(nil)) // expected-error {{duplicate setting passed to #SwiftSettings}}
-#SwiftSettings(.defaultIsolation(nil)) // expected-error {{duplicate setting passed to #SwiftSettings}}
-#SwiftSettings(.defaultIsolation(MyActor.self)) // expected-error {{duplicate setting passed to #SwiftSettings}}
-#SwiftSettings(.defaultIsolation(1)) // expected-error {{duplicate setting passed to #SwiftSettings}}
-// expected-error @-1 {{cannot convert value of type 'Int' to expected argument type 'any Actor.Type'}}
-#SwiftSettings(2) // expected-error {{Unrecognized setting passed to #SwiftSettings}}
-// expected-error @-1 {{cannot convert value of type 'Int' to expected argument type 'SwiftSetting'}}
-
-#SwiftSettings(.defaultIsolation(MainActor.self), // expected-error {{duplicate setting passed to #SwiftSettings}}
-               .defaultIsolation(nil)) // expected-error {{duplicate setting passed to #SwiftSettings}}
-
diff --git a/test/Sema/typo_correction_limit.swift b/test/Sema/typo_correction_limit.swift
index e85c7d308d380..64567106f61ed 100644
--- a/test/Sema/typo_correction_limit.swift
+++ b/test/Sema/typo_correction_limit.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -typo-correction-limit 5
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -typo-correction-limit 5
 
 // This is close enough to get typo-correction.
 func test_short_and_close() {
diff --git a/test/Sema/value_generics.swift b/test/Sema/value_generics.swift
index 0f5d38b9dce15..81904712f67db 100644
--- a/test/Sema/value_generics.swift
+++ b/test/Sema/value_generics.swift
@@ -1,9 +1,13 @@
 // RUN: %target-typecheck-verify-swift -disable-availability-checking
 
 protocol P {}
+protocol Q {}
+class Class {}
 
-func invalid<let N>() {} // expected-error {{value generic 'N' must have an explicit value type declared}}
-                         // expected-error@-1 {{generic parameter 'N' is not used in function signature}}
+func invalid<let N>() { // expected-error {{value generic 'N' must have an explicit value type declared}}
+                        // expected-error@-1 {{generic parameter 'N' is not used in function signature}}
+  let x: String = N // Fine, we bind to a hole.
+}
 func invalid<let N>(_: A<N>) {} // expected-error {{value generic 'N' must have an explicit value type declared}}
 
 struct A<let N: Int> {
@@ -36,8 +40,6 @@ struct A<let N: Int> {
   }
 }
 
-extension A where N: P {} // expected-error {{value generic type 'N' cannot conform to protocol 'P'}}
-
 extension A where N == Int {} // expected-error {{cannot constrain value parameter 'N' to be type 'Int'}}
 
 extension A where N == 123 {
@@ -51,6 +53,8 @@ func c<let M: Int>(with a: A<M>) {} // OK
 func d<T>(with a: A<T>) {} // expected-error {{cannot pass type 'T' as a value for generic value 'N'}}
 func e(with a: A<Int>) {} // expected-error {{cannot pass type 'Int' as a value for generic value 'N'}}
 
+func *<let X: Int, let Y: Int>(l: A<X>, r: A<Y>) -> Int { l.int * r.int }
+
 struct Generic<T: ~Copyable & ~Escapable> {}
 struct GenericWithIntParam<T: ~Copyable & ~Escapable, let N: Int> {}
 
@@ -73,7 +77,38 @@ func m(_: GenericWithIntParam<Int, 123>) {} // OK
 
 typealias One = 1 // expected-error {{expected type in type alias declaration}}
 
-struct B<let N: UInt8> {} // expected-error {{'UInt8' is not a supported value type for 'N'}}
+// Unsupported type in value type parameter definition.
+do {
+  struct S1<let N: UInt8> {}
+  // expected-error@-1:20 {{'UInt8' is not a supported value type for 'N'}}
+  struct S2<let N: Any> {}
+  // expected-error@-1:20 {{'Any' is not a supported value type for 'N'}}
+  struct S3<let N: AnyObject> {}
+  // expected-error@-1:20 {{'AnyObject' is not a supported value type for 'N'}}
+  struct S4<let N: Class> {}
+  // expected-error@-1:20 {{'Class' is not a supported value type for 'N'}}
+  struct S5<let N: P> {}
+  // expected-error@-1:20 {{'P' is not a supported value type for 'N'}}
+  struct S6<let N: P & Q> {}
+  // expected-error@-1:20 {{'P & Q' is not a supported value type for 'N'}}
+  struct S7<let N: ~Copyable> {}
+  // expected-error@-1:20 {{'~Copyable' is not a supported value type for 'N'}}
+}
+
+// Subtype constraint on value type parameter.
+
+struct S1<let x: Int> where x: Class, x: P, x: P & Q, x: Int, x: ~Copyable {}
+// expected-error@-1:30 {{cannot use type constraint with generic value parameter 'x'}}
+// expected-error@-2:40 {{cannot use type constraint with generic value parameter 'x'}}
+// expected-error@-3:46 {{cannot use type constraint with generic value parameter 'x'}}
+// expected-error@-4:56 {{cannot use type constraint with generic value parameter 'x'}}
+// expected-error@-5:64 {{cannot use type constraint with generic value parameter 'x'}}
+extension S1 where x: Class, x: P, x: P & Q, x: Int, x: ~Copyable {}
+// expected-error@-1:21 {{cannot use type constraint with generic value parameter 'x'}}
+// expected-error@-2:31 {{cannot use type constraint with generic value parameter 'x'}}
+// expected-error@-3:37 {{cannot use type constraint with generic value parameter 'x'}}
+// expected-error@-4:47 {{cannot use type constraint with generic value parameter 'x'}}
+// expected-error@-5:55 {{cannot use type constraint with generic value parameter 'x'}}
 
 struct C<let N: Int, let M: Int> {}
 
@@ -119,3 +154,71 @@ func testC4<let T: Int>(with c: C<T, T>) {
 }
 
 struct D<let N: Int & P> {} // expected-error {{non-protocol, non-class type 'Int' cannot be used within a protocol-constrained type}}
+
+struct E<A, let b: Int> { // expected-note {{'b' previously declared here}}
+  static var b: Int { // expected-warning {{redeclaration of 'b' is deprecated and will be an error in Swift 5}}
+                      // expected-note@-1 {{'b' declared here}}
+    123
+  }
+
+  let b: String // expected-note {{'b' previously declared here}}
+                // expected-note@-1 {{'b' declared here}}
+
+  func b() {} // expected-error {{invalid redeclaration of 'b()'}}
+              // expected-note@-1 {{'b' declared here}}
+
+  func dumb() -> Int {
+    Self.b // OK
+  }
+
+  static func dumb2() -> Int {
+    Self.b // OK
+  }
+}
+
+func testE1() -> Int {
+  E<Int, 123>.b // OK
+}
+
+func testE2() -> Int {
+  E<Int, 123>.A // expected-error {{type 'E<Int, 123>' has no member 'A'}}
+}
+
+func testE3<let c: Int>(_: E<Int, c>.Type) -> Int {
+  E<Int, c>.b // OK
+}
+
+func testShadowing<let a: Int>(_: A<a>) {
+  var a: String {
+    "123"
+  }
+
+  let x: String = a // OK
+  let y: Int = a // expected-error {{cannot convert value of type 'String' to specified type 'Int'}}
+
+  print(a) // OK
+  print(a.self) // OK
+}
+
+class F<let n: Int> {}
+class G: F<3> {}
+
+func hello() -> Int {
+  G.n // OK
+}
+
+func testTypeOf() -> Int {
+  let x = E<Int, 123>(b: "")
+  return type(of: x).b // OK
+}
+
+func testTypeOf2<let c: Int>(_: E<Int, c>.Type) -> Int {
+  let x = E<Int, c>(b: "")
+  return type(of: x).b // OK
+}
+
+struct H<let I: Int> { // expected-note {{'I' previously declared here}}
+  struct I {} // expected-warning {{redeclaration of 'I' is deprecated and will be an error in Swift 5}}
+}
+
+typealias J = E<Int, 123>.b // expected-error {{static property 'b' is not a member type of 'E<Int, 123>'}}
diff --git a/test/Sema/value_generics_availability.swift b/test/Sema/value_generics_availability.swift
deleted file mode 100644
index e49b11823f76e..0000000000000
--- a/test/Sema/value_generics_availability.swift
+++ /dev/null
@@ -1,14 +0,0 @@
-// RUN: %target-typecheck-verify-swift
-
-// REQUIRES: OS=macosx
-
-struct A<let N: Int> {} // expected-error {{values in generic types are only available in macOS 99.99.0 or newer}}
-                        // expected-note@-1 {{add @available attribute to enclosing generic struct}}
-
-class B<let N: Int> {} // expected-error {{values in generic types are only available in macOS 99.99.0 or newer}}
-                       // expected-note@-1 {{add @available attribute to enclosing generic class}}
-
-enum C<let N: Int> {} // expected-error {{values in generic types are only available in macOS 99.99.0 or newer}}
-                      // expected-note@-1 {{add @available attribute to enclosing generic enum}}
-
-func something<let N: Int>(_: A<N>) {} // OK, because A can't reference value generics.
diff --git a/test/Sema/where_clause_across_module_boundaries.swift b/test/Sema/where_clause_across_module_boundaries.swift
index d01e4110ee773..311ca6c6859e7 100644
--- a/test/Sema/where_clause_across_module_boundaries.swift
+++ b/test/Sema/where_clause_across_module_boundaries.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -o %t/ModuleA.swiftmodule %S/Inputs/where_clause_across_module_boundaries_module.swift
-// RUN: %target-typecheck-verify-swift -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t
 
 // https://github.com/apple/swift/issues/58084
 // Associated Type Inference fails across module boundaries
diff --git a/test/Serialization/AllowErrors/invalid-operator.swift b/test/Serialization/AllowErrors/invalid-operator.swift
index 00ffc99b89584..61a1f64b5d2df 100644
--- a/test/Serialization/AllowErrors/invalid-operator.swift
+++ b/test/Serialization/AllowErrors/invalid-operator.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend -verify -emit-module -experimental-allow-module-with-compiler-errors %s -o %t/foo.swiftmodule
-// RUN: %target-swift-frontend -verify -emit-module -module-name foo %t/foo.swiftmodule
+// RUN: %target-swift-frontend -verify -verify-ignore-unrelated -emit-module -experimental-allow-module-with-compiler-errors %s -o %t/foo.swiftmodule
+// RUN: %target-swift-frontend -verify -verify-ignore-unrelated -emit-module -module-name foo %t/foo.swiftmodule
 
 // rdar://97267326 – Make sure we can handle an operator function without its declaration.
 struct S {
diff --git a/test/Serialization/AllowErrors/invalid-top.swift b/test/Serialization/AllowErrors/invalid-top.swift
index 07ba3cc70a601..83af2f8ad52cf 100644
--- a/test/Serialization/AllowErrors/invalid-top.swift
+++ b/test/Serialization/AllowErrors/invalid-top.swift
@@ -5,7 +5,7 @@
 // RUN: %{python} %utils/split_file.py -o %t %s
 
 // Errors often only occur during merging, hence creating an empty module here
-// RUN: %target-swift-frontend -verify -module-name errors -emit-module -o %t/mods/errorsmain.partial.swiftmodule -experimental-allow-module-with-compiler-errors %t/errors.swift
+// RUN: %target-swift-frontend -verify -verify-ignore-unrelated -module-name errors -emit-module -o %t/mods/errorsmain.partial.swiftmodule -experimental-allow-module-with-compiler-errors %t/errors.swift
 // RUN: %target-swift-frontend -module-name errors -emit-module -o %t/mods/errorsempty.partial.swiftmodule %t/empty.swift
 // RUN: %target-swift-frontend -module-name errors -emit-module -o %t/mods/errors.swiftmodule -experimental-allow-module-with-compiler-errors %t/mods/errorsmain.partial.swiftmodule %t/mods/errorsempty.partial.swiftmodule
 
diff --git a/test/Serialization/Inputs/borrow_accessor_container.swift b/test/Serialization/Inputs/borrow_accessor_container.swift
new file mode 100644
index 0000000000000..e62aa2855ae39
--- /dev/null
+++ b/test/Serialization/Inputs/borrow_accessor_container.swift
@@ -0,0 +1,40 @@
+public struct Container<Element: ~Copyable >: ~Copyable {
+  var _storage: UnsafeMutableBufferPointer<Element>
+  public let _count: Int
+
+  public init(_ storage: UnsafeMutableBufferPointer<Element>, _ count: Int) {
+    self._storage = storage
+    self._count = count
+  }
+
+  public var count: Int {
+    return _count
+  }
+
+  public var first: Element {
+    @_unsafeSelfDependentResult
+    borrow {
+      return _storage.baseAddress.unsafelyUnwrapped.pointee
+    }
+    @_unsafeSelfDependentResult
+    mutate {
+      return &_storage.baseAddress.unsafelyUnwrapped.pointee
+    }
+  }
+
+  public subscript(index: Int) -> Element {
+    @_unsafeSelfDependentResult
+    borrow {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return _storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee
+    }
+    @_unsafeSelfDependentResult
+    mutate {
+      precondition(index >= 0 && index < _count, "Index out of bounds")
+      return &_storage.baseAddress.unsafelyUnwrapped.advanced(by: index).pointee
+    }
+  }
+}
+
+extension Container: Copyable where Element: Copyable {}
+
diff --git a/test/Serialization/Inputs/caller_inheriting_isolation.swift b/test/Serialization/Inputs/caller_inheriting_isolation.swift
index cd2bd31fc9235..b249da80dbc88 100644
--- a/test/Serialization/Inputs/caller_inheriting_isolation.swift
+++ b/test/Serialization/Inputs/caller_inheriting_isolation.swift
@@ -2,22 +2,22 @@
 public func unspecifiedAsync<T>(_ t: T) async {
 }
 
-@execution(caller)
+nonisolated(nonsending)
 public func unspecifiedAsyncCaller<T>(_ t: T) async {
 }
 
-@execution(concurrent)
+@concurrent
 public func unspecifiedAsyncConcurrent<T>(_ t: T) async {
 }
 
 nonisolated public func nonisolatedAsync<T>(_ t: T) async {
 }
 
-@execution(caller)
-nonisolated public func nonisolatedAsyncCaller<T>(_ t: T) async {
+nonisolated(nonsending)
+public func nonisolatedAsyncCaller<T>(_ t: T) async {
 }
 
-@execution(concurrent)
+@concurrent
 nonisolated public func nonisolatedAsyncConcurrent<T>(_ t: T) async {
 }
 
@@ -26,22 +26,22 @@ public struct S {
   public func unspecifiedAsync<T>(_ t: T) async {
   }
 
-  @execution(caller)
+  nonisolated(nonsending)
   public func unspecifiedAsyncCaller<T>(_ t: T) async {
   }
 
-  @execution(concurrent)
+  @concurrent
   public func unspecifiedAsyncConcurrent<T>(_ t: T) async {
   }
 
   nonisolated public func nonisolatedAsync<T>(_ t: T) async {
   }
 
-  @execution(caller)
-  nonisolated public func nonisolatedAsyncCaller<T>(_ t: T) async {
+  nonisolated(nonsending)
+  public func nonisolatedAsyncCaller<T>(_ t: T) async {
   }
 
-  @execution(concurrent)
+  @concurrent
   nonisolated public func nonisolatedAsyncConcurrent<T>(_ t: T) async {
   }
 }
diff --git a/test/Serialization/Inputs/convention_c_function.swift b/test/Serialization/Inputs/convention_c_function.swift
new file mode 100644
index 0000000000000..5ae74013b29ec
--- /dev/null
+++ b/test/Serialization/Inputs/convention_c_function.swift
@@ -0,0 +1,3 @@
+public func foo(fn: @convention(c) () -> ()) -> () {
+  fn()
+}
diff --git a/test/Serialization/Inputs/def_always_inline.swift b/test/Serialization/Inputs/def_always_inline.swift
index 79709ff9ed70d..e65c470389896 100644
--- a/test/Serialization/Inputs/def_always_inline.swift
+++ b/test/Serialization/Inputs/def_always_inline.swift
@@ -2,6 +2,10 @@
   return x
 }
 
+@inline(always) @inlinable public func testAlwaysInlineGuaranteed(x: Bool) -> Bool {
+  return x
+}
+
 @frozen
 public struct AlwaysInlineInitStruct {
   @usableFromInline
diff --git a/test/Serialization/Inputs/def_basic.sil b/test/Serialization/Inputs/def_basic.sil
index bc78012a84e3b..eb27d1f8eea0b 100644
--- a/test/Serialization/Inputs/def_basic.sil
+++ b/test/Serialization/Inputs/def_basic.sil
@@ -120,6 +120,16 @@ bb0(%0 : $Int):                          // CHECK: bb0(%0 : $Int):
   return %3 : $Int                       // CHECK: return {{.*}} : $Int
 }
 
+// CHECK-LABEL: sil public_external @vector_base_addr :
+// CHECK:         %1 = vector_base_addr %0 : $*Builtin.FixedArray<10, Int>
+// CHECK-LABEL: } // end sil function 'vector_base_addr'
+sil [serialized] @vector_base_addr : $@convention(thin) (@inout Builtin.FixedArray<10, Int>) -> Int {
+bb0(%0 : $*Builtin.FixedArray<10, Int>):
+  %1 = vector_base_addr %0
+  %2 = load %1
+  return %2
+}
+
 // CHECK-LABEL: @call_fn_pointer : $@convention(thin) (() -> Int) -> Int {
 sil [transparent] [serialized] @call_fn_pointer : $@convention(thin) (() -> Int) -> Int {
 bb0(%0 : $() -> Int):
@@ -960,8 +970,17 @@ bb0:
   %3 = apply %0(%2, %1) : $@convention(thin) (Builtin.IntLiteral, @thin Int.Type) -> Int
   return %3 : $Int
 }
-// CHECK-LABEL: [always_inline] @always_inline_callee
-sil [transparent] [serialized] [always_inline] @always_inline_callee : $@convention(thin) () -> Int {
+// CHECK-LABEL: [heuristic_always_inline] @always_inline_callee
+sil [transparent] [serialized] [heuristic_always_inline] @always_inline_callee : $@convention(thin) () -> Int {
+bb0:
+  %0 = function_ref @$sSi33_convertFromBuiltinIntegerLiteralySiBI_cSimF : $@convention(thin) (Builtin.IntLiteral, @thin Int.Type) -> Int
+  %1 = metatype $@thin Int.Type
+  %2 = integer_literal $Builtin.IntLiteral, 0
+  %3 = apply %0(%2, %1) : $@convention(thin) (Builtin.IntLiteral, @thin Int.Type) -> Int
+  return %3 : $Int
+}
+// CHECK-LABEL: [always_inline] @always_inline_callee2
+sil [transparent] [serialized] [always_inline] @always_inline_callee2 : $@convention(thin) () -> Int {
 bb0:
   %0 = function_ref @$sSi33_convertFromBuiltinIntegerLiteralySiBI_cSimF : $@convention(thin) (Builtin.IntLiteral, @thin Int.Type) -> Int
   %1 = metatype $@thin Int.Type
@@ -1479,7 +1498,7 @@ bb0(%0 : $ConformingAssoc):
   return %2 : $()
 }
 
-sil [transparent] [serialized] @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_ : $@convention(witness_method: AssocReqt) (@inout ConformingAssoc) -> () {
+sil [transparent] [serialized] @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_ : $@convention(witness_method: AssocReqt) (@in_guaranteed ConformingAssoc) -> () {
 bb0(%0 : $*ConformingAssoc):
   %1 = load %0 : $*ConformingAssoc
   %2 = function_ref @$s14witness_tables15ConformingAssocV14requiredMethodyyycACF : $@convention(method) (@guaranteed ConformingAssoc) -> ()
@@ -1528,6 +1547,7 @@ bb0:
   %4 = function_ref @test2 : $@convention(thin) (Int) -> ()
   %6 = function_ref @named_tuple : $@convention(thin) () -> (Builtin.Word, Builtin.Word)
   %9 = function_ref @return_int : $@convention(thin) (Int) -> Int
+  %10 = function_ref @vector_base_addr : $@convention(thin) (@inout Builtin.FixedArray<10, Int>) -> Int
   %11 = function_ref @call_fn_pointer : $@convention(thin) (() -> Int) -> Int
   %13 = function_ref @return_constant : $@convention(thin) () -> Int
   %23 = function_ref @existentials : $@convention(thin) (@in P) -> ()
@@ -1582,6 +1602,7 @@ bb0:
   %110 = function_ref @test_thunk : $@convention(thin) () -> ()
   %130 = function_ref @noinline_callee : $@convention(thin) () -> Int
   %132 = function_ref @always_inline_callee : $@convention(thin) () -> Int
+  %161 = function_ref @always_inline_callee2 : $@convention(thin) () -> Int
   %131 = function_ref @test_semantics : $@convention(thin) () -> ()
   %136 = function_ref @test_onone : $@convention(thin) () -> ()
   %137 = function_ref @test_ospeed : $@convention(thin) () -> ()
diff --git a/test/Serialization/Inputs/def_explicit_lifetime_dependence.swift b/test/Serialization/Inputs/def_explicit_lifetime_dependence.swift
index 05094ef6e9689..d1b78680a4bc9 100644
--- a/test/Serialization/Inputs/def_explicit_lifetime_dependence.swift
+++ b/test/Serialization/Inputs/def_explicit_lifetime_dependence.swift
@@ -1,6 +1,6 @@
 public struct AnotherView : ~Escapable {
   let ptr: UnsafeRawBufferPointer
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   public init(_ ptr: UnsafeRawBufferPointer) {
     self.ptr = ptr
   }
@@ -9,19 +9,19 @@ public struct AnotherView : ~Escapable {
 public struct BufferView : ~Escapable {
   public let ptr: UnsafeRawBufferPointer
   @inlinable
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   public init(_ ptr: UnsafeRawBufferPointer) {
     self.ptr = ptr
   }
-  @lifetime(borrow a)
+  @_lifetime(borrow a)
   public init(_ ptr: UnsafeRawBufferPointer, _ a: borrowing Array<Int>) {
     self.ptr = ptr
   }
-  @lifetime(copy a)
+  @_lifetime(copy a)
   public init(_ ptr: UnsafeRawBufferPointer, _ a: consuming AnotherView) {
     self.ptr = ptr
   }
-  @lifetime(copy a, borrow b)
+  @_lifetime(copy a, borrow b)
   public init(_ ptr: UnsafeRawBufferPointer, _ a: consuming AnotherView, _ b: borrowing Array<Int>) {
     self.ptr = ptr
   }
@@ -29,31 +29,31 @@ public struct BufferView : ~Escapable {
 
 public struct MutableBufferView : ~Escapable, ~Copyable {
   let ptr: UnsafeMutableRawBufferPointer
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   public init(_ ptr: UnsafeMutableRawBufferPointer) {
     self.ptr = ptr
   }
 }
 
 @inlinable
-@lifetime(borrow x)
+@_lifetime(borrow x)
 public func derive(_ x: borrowing BufferView) -> BufferView {
   return BufferView(x.ptr)
 }
 
 public func use(_ x: borrowing BufferView) {}
 
-@lifetime(borrow view)
+@_lifetime(borrow view)
 public func borrowAndCreate(_ view: borrowing BufferView) -> BufferView {
   return BufferView(view.ptr)
 }
 
-@lifetime(copy view)
+@_lifetime(copy view)
 public func consumeAndCreate(_ view: consuming BufferView) -> BufferView {
   return BufferView(view.ptr)
 }
 
-@lifetime(borrow this, copy that)
+@_lifetime(borrow this, copy that)
 public func deriveThisOrThat(_ this: borrowing BufferView, _ that: borrowing BufferView) -> BufferView {
   if (Int.random(in: 1..<100) == 0) {
     return BufferView(this.ptr)
@@ -63,16 +63,16 @@ public func deriveThisOrThat(_ this: borrowing BufferView, _ that: borrowing Buf
 
 public struct Wrapper : ~Escapable {
   var _view: BufferView
-  @lifetime(copy view)
+  @_lifetime(copy view)
   public init(_ view: consuming BufferView) {
     self._view = view
   }
   public var view: BufferView {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield _view
     }
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &_view
     }
@@ -86,7 +86,7 @@ public enum FakeOptional<Wrapped: ~Escapable>: ~Escapable {
 extension FakeOptional: Escapable where Wrapped: Escapable {}
 
 extension FakeOptional where Wrapped: ~Escapable {
-  @lifetime(immortal)
+  @_lifetime(immortal)
   public init(_ nilLiteral: ()) {
     self = .none
   }
diff --git a/test/Serialization/Inputs/def_implicit_lifetime_dependence.swift b/test/Serialization/Inputs/def_implicit_lifetime_dependence.swift
index 8a327ce4fdbdf..acf05997061e7 100644
--- a/test/Serialization/Inputs/def_implicit_lifetime_dependence.swift
+++ b/test/Serialization/Inputs/def_implicit_lifetime_dependence.swift
@@ -1,13 +1,13 @@
 public struct BufferView : ~Escapable {
   public let ptr: UnsafeRawBufferPointer
   public let c: Int
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   public init(_ ptr: UnsafeRawBufferPointer, _ c: Int) {
     self.ptr = ptr
     self.c = c
   }
   @inlinable
-  @lifetime(copy otherBV)
+  @_lifetime(copy otherBV)
   public init(_ otherBV: borrowing BufferView) {
     self.ptr = otherBV.ptr
     self.c = otherBV.c
@@ -17,7 +17,7 @@ public struct BufferView : ~Escapable {
 public struct MutableBufferView : ~Escapable, ~Copyable {
   let ptr: UnsafeMutableRawBufferPointer
   let c: Int
-  @lifetime(borrow ptr)
+  @_lifetime(borrow ptr)
   public init(_ ptr: UnsafeMutableRawBufferPointer, _ c: Int) {
     self.ptr = ptr
     self.c = c
@@ -25,17 +25,17 @@ public struct MutableBufferView : ~Escapable, ~Copyable {
 }
 
 @inlinable
-@lifetime(copy x)
+@_lifetime(copy x)
 public func derive(_ x: borrowing BufferView) -> BufferView {
   return BufferView(x.ptr, x.c)
 }
 
-@lifetime(copy view)
+@_lifetime(copy view)
 public func borrowAndCreate(_ view: borrowing BufferView) -> BufferView {
   return BufferView(view.ptr, view.c )
 }
 
-@lifetime(copy view)
+@_lifetime(copy view)
 public func consumeAndCreate(_ view: consuming BufferView) -> BufferView {
   return BufferView(view.ptr, view.c)
 }
@@ -58,16 +58,16 @@ public struct Container : ~Copyable {
 public struct Wrapper : ~Escapable {
   var _view: BufferView
   public var view: BufferView {
-    @lifetime(copy self)
+    @_lifetime(copy self)
     _read {
       yield _view
     }
-    @lifetime(borrow self)
+    @_lifetime(&self)
     _modify {
       yield &_view
     }
   }
-  @lifetime(copy view)
+  @_lifetime(copy view)
   public init(_ view: consuming BufferView) {
     self._view = view
   }
diff --git a/test/Serialization/Inputs/def_isolated_conformance.swift b/test/Serialization/Inputs/def_isolated_conformance.swift
index a339a12a77764..f908f1eac1648 100644
--- a/test/Serialization/Inputs/def_isolated_conformance.swift
+++ b/test/Serialization/Inputs/def_isolated_conformance.swift
@@ -8,3 +8,8 @@ public class MyClass { }
 extension MyClass: @MainActor MyProtocol {
   @MainActor public func f() { }
 }
+
+public protocol OtherProtocol {
+}
+
+extension MyClass: OtherProtocol { }
diff --git a/test/Serialization/Inputs/def_lifetime_dependence_enums.swift b/test/Serialization/Inputs/def_lifetime_dependence_enums.swift
new file mode 100644
index 0000000000000..1ddaa8c117390
--- /dev/null
+++ b/test/Serialization/Inputs/def_lifetime_dependence_enums.swift
@@ -0,0 +1,29 @@
+public protocol OptionalType<Wrapped> {
+  associatedtype Wrapped
+
+  static func some(_ wrapped: Wrapped) -> Self
+  static func somePair(_ wrapped1: Wrapped, _ wrapped2: Wrapped) -> Self
+  static func esc(_ e: E) -> Self
+}
+
+public struct E {}
+
+public enum FakeOptional<Wrapped : ~Escapable & ~Copyable> : ~Escapable & ~Copyable {
+  case none
+  case some(Wrapped)
+  case somePair(Wrapped, Wrapped)
+  case esc(E)
+}
+
+extension FakeOptional: Copyable where Wrapped: Copyable & ~Escapable {}
+
+extension FakeOptional: Escapable where Wrapped: Escapable & ~Copyable {}
+
+extension FakeOptional : OptionalType {}
+
+// CHECK-LABEL: sil shared [transparent] @$s25lifetime_dependence_enums12FakeOptionalO4someyACyxGxcAEmlF : $@convention(method) <Wrapped where Wrapped : ~Copyable, Wrapped : ~Escapable> (@in Wrapped, @thin FakeOptional<Wrapped>.Type) -> @lifetime(copy 0) @out FakeOptional<Wrapped> {
+
+// CHECK-LABEL: sil shared [transparent] @$s25lifetime_dependence_enums12FakeOptionalO8somePairyACyxGx_xtcAEmlF : $@convention(method) <Wrapped where Wrapped : ~Copyable, Wrapped : ~Escapable> (@in Wrapped, @in Wrapped, @thin FakeOptional<Wrapped>.Type) -> @lifetime(copy 0, copy 1) @out FakeOptional<Wrapped> {
+
+// CHECK-LABEL: sil shared [transparent] @$s25lifetime_dependence_enums12FakeOptionalO3escyACyxGAA1EVcAEmlF : $@convention(method) <Wrapped where Wrapped : ~Copyable, Wrapped : ~Escapable> (E, @thin FakeOptional<Wrapped>.Type) -> @out FakeOptional<Wrapped> {
+
diff --git a/test/Serialization/Inputs/lifetime_dependence.swift b/test/Serialization/Inputs/lifetime_dependence.swift
new file mode 100644
index 0000000000000..6d547e070d8da
--- /dev/null
+++ b/test/Serialization/Inputs/lifetime_dependence.swift
@@ -0,0 +1,23 @@
+import Builtin
+
+@frozen
+@safe
+public struct Ref<T: ~Copyable>: Copyable, ~Escapable {
+  @usableFromInline
+  let _pointer: UnsafePointer<T>
+
+  @_lifetime(borrow value)
+  @_alwaysEmitIntoClient
+  @_transparent
+  public init(_ value: borrowing @_addressable T) {
+    unsafe _pointer = UnsafePointer(Builtin.unprotectedAddressOfBorrow(value))
+  }
+
+  @_alwaysEmitIntoClient
+  public subscript() -> T {
+    @_transparent
+    unsafeAddress {
+      unsafe _pointer
+    }
+  }
+}
diff --git a/test/Serialization/Inputs/ne_types.swift b/test/Serialization/Inputs/ne_types.swift
new file mode 100644
index 0000000000000..1e2dc638c1d40
--- /dev/null
+++ b/test/Serialization/Inputs/ne_types.swift
@@ -0,0 +1,98 @@
+@_addressableForDependencies
+public struct Something {
+  public struct View<T: BitwiseCopyable> : ~Copyable, ~Escapable {
+    var ptr: UnsafeBufferPointer<T>
+    
+    @_lifetime(borrow ptr)
+    public init(ptr: borrowing UnsafeBufferPointer<T>) {
+      self.ptr = copy ptr
+    }
+    
+    public var span: Span<T> {
+      @_lifetime(borrow self)
+      borrowing get {
+        Span(_unsafeElements: ptr)
+      }
+    }
+  }
+  
+  public struct MutableView<T: BitwiseCopyable> : ~Copyable, ~Escapable {
+    var ptr: UnsafeMutableBufferPointer<T>
+    
+    @_lifetime(borrow ptr)
+    public init(ptr: borrowing UnsafeMutableBufferPointer<T>) {
+      self.ptr = copy ptr
+    }
+    
+    public var mutableSpan: MutableSpan<T> {
+      @_lifetime(&self)
+      mutating get {
+        MutableSpan(_unsafeElements: ptr)
+      }
+    }
+  }
+  
+  var ptr: UnsafeMutableRawBufferPointer
+  public init(ptr: UnsafeMutableRawBufferPointer) {
+    self.ptr = ptr
+  }
+  
+  @_lifetime(borrow self)
+  public func view<T>(of type: T.Type = T.self) -> View<T> {
+    let tp = ptr.assumingMemoryBound(to: T.self)
+    return __overrideLifetime(View(ptr: .init(tp)), borrowing: self)
+  }
+  
+  @_lifetime(&self)
+  public mutating func mutableView<T>(of type: T.Type = T.self) -> MutableView<T> {
+    let tp = ptr.assumingMemoryBound(to: T.self)
+    return __overrideLifetime(MutableView(ptr: tp), mutating: &self)
+  }
+}
+
+@unsafe
+@_unsafeNonescapableResult
+@_alwaysEmitIntoClient
+@_transparent
+@_lifetime(borrow source)
+public func __overrideLifetime<
+  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
+>(
+  _ dependent: consuming T, borrowing source: borrowing U
+) -> T {
+  dependent
+}
+
+/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
+/// a value identical to `dependent` that inherits all lifetime dependencies from
+/// the `source` argument.
+@unsafe
+@_unsafeNonescapableResult
+@_alwaysEmitIntoClient
+@_transparent
+@_lifetime(copy source)
+public func __overrideLifetime<
+  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
+>(
+  _ dependent: consuming T, copying source: borrowing U
+) -> T {
+  dependent
+}
+
+/// Unsafely discard any lifetime dependency on the `dependent` argument.
+/// Return a value identical to `dependent` with a lifetime dependency
+/// on the caller's exclusive borrow scope of the `source` argument.
+@unsafe
+@_unsafeNonescapableResult
+@_alwaysEmitIntoClient
+@_transparent
+@_lifetime(&source)
+public func __overrideLifetime<
+  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
+>(
+  _ dependent: consuming T,
+  mutating source: inout U
+) -> T {
+  dependent
+}
+
diff --git a/test/Serialization/Recovery/conformance-xref.swift b/test/Serialization/Recovery/conformance-xref.swift
index 949e26f5553ac..f27fe2fe6476c 100644
--- a/test/Serialization/Recovery/conformance-xref.swift
+++ b/test/Serialization/Recovery/conformance-xref.swift
@@ -20,7 +20,7 @@
 
 /// No errors when extended recovery is enabled.
 // RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
-// RUN:   -experimental-allow-module-with-compiler-errors -verify
+// RUN:   -experimental-allow-module-with-compiler-errors -verify -verify-ignore-unrelated
 
 /// Case 2: Remove a requirement from one lib, leave the other as stale and
 /// rebuild client. Error on the mismatch.
@@ -34,7 +34,7 @@
 
 /// No errors when extended recovery is enabled.
 // RUN: %target-swift-frontend -typecheck %t/Client.swift -I %t \
-// RUN:   -experimental-allow-module-with-compiler-errors -verify
+// RUN:   -experimental-allow-module-with-compiler-errors -verify -verify-ignore-unrelated
 
 /// Combined case: Remove both the conformance and the requirement.
 /// Fail on the removed conformance only as it was first.
@@ -68,7 +68,7 @@ public protocol ProtoUser {
 // CHECK-REMARK-REQUIREMENT: Conformances:
 // Skipping implicits.
 // CHECK-REMARK-REQUIREMENT: (specialized_conformance type="OneToAThousand.Impl" protocol="SimpleProto"
-// CHECK-REMARK-REQUIREMENT:   (normal_conformance type="Counter<T>" protocol="SimpleProto" lazy))
+// CHECK-REMARK-REQUIREMENT:   (normal_conformance type="Counter<T>" protocol="SimpleProto"{{.*}} lazy))
   associatedtype Impl
 #else
   associatedtype Impl: SimpleProto
diff --git a/test/Serialization/Recovery/crash-recovery.swift b/test/Serialization/Recovery/crash-recovery.swift
index d3543bca6669c..9397b2795f0c8 100644
--- a/test/Serialization/Recovery/crash-recovery.swift
+++ b/test/Serialization/Recovery/crash-recovery.swift
@@ -16,7 +16,7 @@ public class Sub: Base {
 // CHECK-CRASH: error: fatal error encountered while reading from module 'Lib'; please submit a bug report (https://swift.org/contributing/#reporting-bugs){{$}}
 // CHECK-CRASH-4: Compiling with effective version 4.1.50
 // CHECK-CRASH-4_2: Compiling with effective version 4.2
-// CHECK-CRASH: While loading members for 'Sub' (in module 'Lib')
+// CHECK-CRASH-LABEL: While loading members for 'Sub' (in module 'Lib')
 // CHECK-CRASH-LABEL: *** DESERIALIZATION FAILURE ***
 // CHECK-CRASH-LABEL: *** If any module named here was modified in the SDK, please delete the ***
 // CHECK-CRASH-LABEL: *** new swiftmodule files from the SDK and keep only swiftinterfaces.   ***
diff --git a/test/Serialization/Recovery/typedefs-in-enums.swift b/test/Serialization/Recovery/typedefs-in-enums.swift
index 1f935a581a1b2..cbdfb694abb96 100644
--- a/test/Serialization/Recovery/typedefs-in-enums.swift
+++ b/test/Serialization/Recovery/typedefs-in-enums.swift
@@ -5,7 +5,7 @@
 
 // RUN: %target-swift-ide-test -source-filename=x -print-module -module-to-print Lib -I %t -I %S/Inputs/custom-modules -Xcc -DBAD | %FileCheck -check-prefix CHECK-RECOVERY %s
 
-// RUN: %target-swift-frontend -typecheck -I %t -I %S/Inputs/custom-modules -Xcc -DBAD -DTEST %s -verify
+// RUN: %target-swift-frontend -typecheck -I %t -I %S/Inputs/custom-modules -Xcc -DBAD -DTEST %s -verify -verify-ignore-unrelated
 
 #if TEST
 
diff --git a/test/Serialization/Recovery/typedefs.swift b/test/Serialization/Recovery/typedefs.swift
index 15715a967736c..569686728b528 100644
--- a/test/Serialization/Recovery/typedefs.swift
+++ b/test/Serialization/Recovery/typedefs.swift
@@ -10,13 +10,13 @@
 // RUN: %FileCheck -check-prefix CHECK-RECOVERY %s < %t.txt
 // RUN: %FileCheck -check-prefix CHECK-RECOVERY-NEGATIVE %s < %t.txt
 
-// RUN: %target-swift-frontend -typecheck -I %t -I %S/Inputs/custom-modules -Xcc -DBAD -DTEST -DVERIFY %s -verify
+// RUN: %target-swift-frontend -typecheck -I %t -I %S/Inputs/custom-modules -Xcc -DBAD -DTEST -DVERIFY %s -verify -verify-ignore-unrelated
 // RUN: %target-swift-frontend -emit-silgen -I %t -I %S/Inputs/custom-modules -Xcc -DBAD -DTEST %s | %FileCheck -check-prefix CHECK-SIL %s
 
 // RUN: %target-swift-frontend -emit-ir -I %t -I %S/Inputs/custom-modules -DTEST %s | %FileCheck --check-prefixes=CHECK-IR,CHECK-IR-%target-runtime %s
 // RUN: %target-swift-frontend -emit-ir -I %t -I %S/Inputs/custom-modules -Xcc -DBAD -DTEST %s | %FileCheck --check-prefixes=CHECK-IR,CHECK-IR-%target-runtime %s
 
-// RUN: %target-swift-frontend -typecheck -I %t -I %S/Inputs/custom-modules -Xcc -DBAD %S/Inputs/typedefs-helper.swift -verify
+// RUN: %target-swift-frontend -typecheck -I %t -I %S/Inputs/custom-modules -Xcc -DBAD %S/Inputs/typedefs-helper.swift -verify -verify-ignore-unrelated
 
 #if TEST
 
@@ -45,11 +45,13 @@ public func testVTableBuilding(user: User) {
 
 #if VERIFY
 let _: String = useAssoc(ImportedType.self) // expected-error {{cannot convert value of type 'Int32?' to specified type 'String'}}
-let _: Bool? = useAssoc(ImportedType.self) // expected-error {{cannot convert value of type 'Int32?' to specified type 'Bool?'}}
+let _: Bool? = useAssoc(ImportedType.self) // expected-error {{cannot assign value of type 'Int32?' to type 'Bool?'}}
+// expected-note@-1 {{arguments to generic parameter 'Wrapped' ('Int32' and 'Bool') are expected to be equal}}
 let _: Int32? = useAssoc(ImportedType.self)
 
 let _: String = useAssoc(AnotherType.self) // expected-error {{cannot convert value of type 'AnotherType.Assoc?' (aka 'Optional<Int32>') to specified type 'String'}}
-let _: Bool? = useAssoc(AnotherType.self) // expected-error {{cannot convert value of type 'AnotherType.Assoc?' (aka 'Optional<Int32>') to specified type 'Bool?'}}
+let _: Bool? = useAssoc(AnotherType.self) // expected-error {{cannot assign value of type 'AnotherType.Assoc?' (aka 'Optional<Int32>') to type 'Bool?'}}
+// expected-note@-1 {{arguments to generic parameter 'Wrapped' ('AnotherType.Assoc' (aka 'Int32') and 'Bool') are expected to be equal}}
 let _: Int32? = useAssoc(AnotherType.self)
 
 let _ = wrapped // expected-error {{cannot find 'wrapped' in scope}}
diff --git a/test/Serialization/Recovery/types-4-to-5.swift b/test/Serialization/Recovery/types-4-to-5.swift
index 510942e5f471d..4a0cde5851416 100644
--- a/test/Serialization/Recovery/types-4-to-5.swift
+++ b/test/Serialization/Recovery/types-4-to-5.swift
@@ -5,7 +5,7 @@
 
 // RUN: %target-swift-ide-test -source-filename=x -print-module -module-to-print Lib -I %t -I %S/Inputs/custom-modules -swift-version 5 | %FileCheck -check-prefix=CHECK-5 %s
 
-// RUN: %target-swift-frontend -typecheck %s -I %t -I %S/Inputs/custom-modules  -swift-version 5 -D TEST -verify
+// RUN: %target-swift-frontend -typecheck %s -I %t -I %S/Inputs/custom-modules  -swift-version 5 -D TEST -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/Serialization/always_inline.swift b/test/Serialization/always_inline.swift
index 933c33887fdca..347ef280a528d 100644
--- a/test/Serialization/always_inline.swift
+++ b/test/Serialization/always_inline.swift
@@ -1,24 +1,34 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/def_always_inline.swift
+// RUN: %target-swift-frontend -enable-experimental-feature InlineAlways -emit-module -o %t %S/Inputs/def_always_inline.swift
 // RUN: llvm-bcanalyzer %t/def_always_inline.swiftmodule | %FileCheck %s
 // RUN: %target-swift-frontend -emit-sib -I %t %s -o %t/always_inline.sib
 // RUN: %target-sil-opt -sil-print-types -performance-linker %t/always_inline.sib -I %t -emit-sorted-sil | %FileCheck %s -check-prefix=SIL
 
+// REQUIRES: swift_feature_InlineAlways
+
 // CHECK-NOT: UnknownCode
 
 import def_always_inline
 
-// SIL-LABEL: sil public_external [serialized] [always_inline] [canonical] [ossa] @$s17def_always_inline16testAlwaysInline1xS2b_tF : $@convention(thin) (Bool) -> Bool {
+// SIL-LABEL: sil public_external [serialized] [heuristic_always_inline] [canonical] [ossa] @$s17def_always_inline16testAlwaysInline1xS2b_tF : $@convention(thin) (Bool) -> Bool {
 
-// SIL-LABEL: sil public_external [serialized] [always_inline] [canonical] [ossa] @$s17def_always_inline22AlwaysInlineInitStructV1xACSb_tcfC : $@convention(method) (Bool, @thin AlwaysInlineInitStruct.Type) -> AlwaysInlineInitStruct {
+// SIL-LABEL: sil public_external [serialized] [heuristic_always_inline] [canonical] [ossa] @$s17def_always_inline22AlwaysInlineInitStructV1xACSb_tcfC : $@convention(method) (Bool, @thin AlwaysInlineInitStruct.Type) -> AlwaysInlineInitStruct {
 
 // SIL-LABEL: sil [ossa] @main
 // SIL: [[RAW:%.+]] = global_addr @$s13always_inline3rawSbvp : $*Bool
 // SIL: [[FUNC:%.+]] = function_ref @$s17def_always_inline16testAlwaysInline1xS2b_tF : $@convention(thin) (Bool) -> Bool
 // SIL: [[RESULT:%.+]] = apply [[FUNC]]({{%.+}}) : $@convention(thin) (Bool) -> Bool
 // SIL: store [[RESULT]] to [trivial] [[RAW]] : $*Bool
+//   inlined  testAlwaysInlineGuaranteed
+// SIL: [[RAW2:%.*]] = global_addr @$s13always_inline4raw2Sbvp
+// SIL: [[FALSE:%.*]] = integer_literal $Builtin.Int1, 0
+// SIL: [[FALSE2:%.*]] = struct $Bool ([[FALSE]] : $Builtin.Int1)
+// SIL: store [[FALSE2]] to [trivial] [[RAW2]] : $*Bool
+
 var raw = testAlwaysInline(x: false)
 
+var raw2 = testAlwaysInlineGuaranteed(x: false)
+
 // SIL: [[FUNC2:%.+]] = function_ref @$s17def_always_inline22AlwaysInlineInitStructV1xACSb_tcfC : $@convention(method) (Bool, @thin AlwaysInlineInitStruct.Type) -> AlwaysInlineInitStruct
 // SIL: apply [[FUNC2]]({{%.+}}, {{%.+}}) : $@convention(method) (Bool, @thin AlwaysInlineInitStruct.Type) -> AlwaysInlineInitStruct
 var a = AlwaysInlineInitStruct(x: false)
diff --git a/test/Serialization/attr-expose.swift b/test/Serialization/attr-expose.swift
new file mode 100644
index 0000000000000..b57b6f5f87cb8
--- /dev/null
+++ b/test/Serialization/attr-expose.swift
@@ -0,0 +1,31 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend  -module-name attr_expose -emit-module -parse-as-library -o %t %s
+// RUN: %target-sil-opt -enable-sil-verify-all %t/attr_expose.swiftmodule | %FileCheck %s
+
+// @_expose
+// -----------------------------------------------------------------------------
+
+// CHECK:      @_expose(Cxx)
+// CHECK-NEXT: func exposeToCxx()
+@_expose(Cxx)
+func exposeToCxx() -> Int { return 42 }
+
+// CHECK:      @_expose(Cxx, "custom_name")
+// CHECK-NEXT: func exposeToCxxWithName()
+@_expose(Cxx, "custom_name")
+func exposeToCxxWithName() -> Int { return 24 }
+
+// CHECK:      @_expose(!Cxx)
+// CHECK-NEXT: func dontExposeToCxx()
+@_expose(!Cxx)
+func dontExposeToCxx() -> Int { return 13 }
+
+// CHECK:      @_expose(wasm)
+// CHECK-NEXT: func exposeToWasm()
+@_expose(wasm)
+func exposeToWasm() -> Int { return 99 }
+
+// CHECK:     @_expose(wasm, "wasm_custom")
+// CHECK-NEXT func exposeToWasmWithName()
+@_expose(wasm, "wasm_custom")
+func exposeToWasmWithName() -> Int { return 88 }
diff --git a/test/Serialization/attr-inline-always.swift b/test/Serialization/attr-inline-always.swift
new file mode 100644
index 0000000000000..740f9001fae86
--- /dev/null
+++ b/test/Serialization/attr-inline-always.swift
@@ -0,0 +1,13 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -enable-experimental-feature InlineAlways -emit-module-path %t/a.swiftmodule -module-name a %s
+// RUN: llvm-bcanalyzer -dump %t/a.swiftmodule | %FileCheck --check-prefix BC-CHECK --implicit-check-not UnknownCode %s
+// RUN: %target-swift-ide-test -print-module -module-to-print a -source-filename x -I %t | %FileCheck --check-prefix MODULE-CHECK %s
+
+// REQUIRES: swift_feature_InlineAlways
+
+// BC-CHECK: <Inline_DECL_ATTR
+
+// MODULE-CHECK: @inline(always) func inlineAlwaysFunc()
+
+@inline(always)
+public func inlineAlwaysFunc() {}
diff --git a/test/Serialization/availability_custom_domains.swift b/test/Serialization/availability_custom_domains.swift
new file mode 100644
index 0000000000000..5500c214d9a8d
--- /dev/null
+++ b/test/Serialization/availability_custom_domains.swift
@@ -0,0 +1,38 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/modules)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %t/lib.swift \
+// RUN:   -emit-module-path %t/modules/lib.swiftmodule -module-name lib \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -enable-experimental-feature CustomAvailability
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %t/client.swift \
+// RUN:   -typecheck -verify -verify-ignore-unrelated \
+// RUN:   -I %S/../Inputs/custom-modules/availability-domains \
+// RUN:   -I %t/modules -enable-experimental-feature CustomAvailability
+
+// REQUIRES: swift_feature_CustomAvailability
+
+// https://github.com/swiftlang/swift/issues/80058
+// UNSUPPORTED: OS=linux-android
+
+//--- lib.swift
+
+import Oceans // re-exports Rivers
+
+@available(Pacific)
+public func availableInPacific() { }
+
+@available(Colorado, unavailable)
+public func unavailableInColorado() { }
+
+//--- client.swift
+
+import lib
+
+func test() { // expected-note {{add '@available' attribute to enclosing global function}}
+  availableInPacific() // expected-error {{'availableInPacific()' is only available in Pacific}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  unavailableInColorado() // expected-error {{'unavailableInColorado()' is unavailable}}
+}
diff --git a/test/Serialization/borrow_accessor_client.swift b/test/Serialization/borrow_accessor_client.swift
new file mode 100644
index 0000000000000..aa39c8806d837
--- /dev/null
+++ b/test/Serialization/borrow_accessor_client.swift
@@ -0,0 +1,38 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -module-name borrow_accessor_container -enable-experimental-feature BorrowAndMutateAccessors -o %t %S/Inputs/borrow_accessor_container.swift
+// RUN: %target-swift-frontend -I %t -emit-sil %s -verify | %FileCheck %s
+
+// REQUIRES: swift_feature_BorrowAndMutateAccessors
+
+import borrow_accessor_container
+
+func test() {
+  let n = 10_000
+  var arr = Array(0...n)
+  let count = arr.count
+  let sum = arr.withUnsafeMutableBufferPointer { ubpointer in
+    let container = Container(ubpointer, count)
+    var sum = 0
+    for i in 0..<container._count {
+      sum &+= container[i]
+    }
+    return sum
+  }
+  let expectedSum = n * (n + 1) / 2
+  assert(sum == expectedSum)
+  let mutated_sum = arr.withUnsafeMutableBufferPointer { ubpointer in
+    var container = Container(ubpointer, count)
+    var sum = 0
+    for i in 0..<container._count {
+      container[i] &+= 1
+      sum += container[i]
+    }
+    return sum
+  }
+  let mutatedExpectedSum = (n + 1) * (n + 2) / 2
+  assert(mutated_sum == mutatedExpectedSum)
+}
+
+// CHECK: sil @$s25borrow_accessor_container9ContainerVAARi_zrlEyxSicib : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (Int, @guaranteed Container<τ_0_0>) -> @guaranteed_addr τ_0_0
+// CHECK: sil @$s25borrow_accessor_container9ContainerVAARi_zrlEyxSiciz : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable> (Int, @inout Container<τ_0_0>) -> @guaranteed_addr τ_0_0
+
diff --git a/test/Serialization/builtin.swift b/test/Serialization/builtin.swift
index cce143203088b..18b83685b72c3 100644
--- a/test/Serialization/builtin.swift
+++ b/test/Serialization/builtin.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -parse-stdlib -o %t %S/Inputs/alias_builtin.swift
 // RUN: llvm-bcanalyzer %t/alias_builtin.swiftmodule | %FileCheck %s
-// RUN: %target-swift-frontend -I %t -typecheck %s -verify
+// RUN: %target-swift-frontend -I %t -typecheck %s -verify -verify-ignore-unrelated
 
 // CHECK-NOT: UnknownCode
 
diff --git a/test/Serialization/caller_isolation_inherit.swift b/test/Serialization/caller_isolation_inherit.swift
index d58f749dd0b62..632d746f549ae 100644
--- a/test/Serialization/caller_isolation_inherit.swift
+++ b/test/Serialization/caller_isolation_inherit.swift
@@ -1,14 +1,13 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-experimental-feature ExecutionAttribute -enable-experimental-feature AsyncCallerExecution -emit-module-path %t/WithFeature.swiftmodule -module-name WithFeature %S/Inputs/caller_inheriting_isolation.swift -swift-version 6
-// RUN: %target-swift-frontend -enable-experimental-feature ExecutionAttribute -emit-module-path %t/WithoutFeature.swiftmodule -module-name WithoutFeature %S/Inputs/caller_inheriting_isolation.swift -swift-version 6
+// RUN: %target-swift-frontend -enable-upcoming-feature NonisolatedNonsendingByDefault -emit-module-path %t/WithFeature.swiftmodule -module-name WithFeature %S/Inputs/caller_inheriting_isolation.swift -swift-version 6
+// RUN: %target-swift-frontend -emit-module-path %t/WithoutFeature.swiftmodule -module-name WithoutFeature %S/Inputs/caller_inheriting_isolation.swift -swift-version 6
 
 // RUN: %target-swift-frontend -module-name main -I %t %s -emit-sil -o - | %FileCheck %s
 
-// RUN: %target-swift-frontend -enable-experimental-feature ExecutionAttribute -enable-experimental-feature AsyncCallerExecution -module-name main -I %t %s -emit-sil -verify -swift-version 6
+// RUN: %target-swift-frontend -enable-upcoming-feature NonisolatedNonsendingByDefault -module-name main -I %t %s -emit-sil -verify -swift-version 6
 
 // REQUIRES: asserts
-// REQUIRES: swift_feature_ExecutionAttribute
-// REQUIRES: swift_feature_AsyncCallerExecution
+// REQUIRES: swift_feature_NonisolatedNonsendingByDefault
 
 import WithFeature
 import WithoutFeature
@@ -33,7 +32,7 @@ actor A {
   func test1a() async {
     await WithFeature.unspecifiedAsyncConcurrent(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated global function 'unspecifiedAsyncConcurrent' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent global function 'unspecifiedAsyncConcurrent' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // unspecifiedAsyncCaller<A>(_:)
@@ -49,7 +48,7 @@ actor A {
   func test2() async {
     await WithoutFeature.unspecifiedAsync(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated global function 'unspecifiedAsync' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent global function 'unspecifiedAsync' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // unspecifiedAsyncConcurrent<A>(_:)
@@ -60,7 +59,7 @@ actor A {
     // an error.
     await WithoutFeature.unspecifiedAsyncConcurrent(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated global function 'unspecifiedAsyncConcurrent' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent global function 'unspecifiedAsyncConcurrent' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // unspecifiedAsyncCaller<A>(_:)
@@ -83,7 +82,7 @@ actor A {
   func test3a() async {
     await WithFeature.nonisolatedAsyncConcurrent(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated global function 'nonisolatedAsyncConcurrent' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent global function 'nonisolatedAsyncConcurrent' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // nonisolatedAsyncCaller<A>(_:)
@@ -99,7 +98,7 @@ actor A {
   func test4() async {
     await WithoutFeature.nonisolatedAsync(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated global function 'nonisolatedAsync' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent global function 'nonisolatedAsync' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // nonisolatedAsyncConcurrent<A>(_:)
@@ -108,7 +107,7 @@ actor A {
   func test4a() async {
     await WithoutFeature.nonisolatedAsyncConcurrent(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated global function 'nonisolatedAsyncConcurrent' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent global function 'nonisolatedAsyncConcurrent' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // nonisolatedAsyncCaller<A>(_:)
@@ -133,7 +132,7 @@ actor A {
     let s = WithFeature.S()
     await s.unspecifiedAsyncConcurrent(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated instance method 'unspecifiedAsyncConcurrent' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent instance method 'unspecifiedAsyncConcurrent' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // S.unspecifiedAsyncCaller<A>(_:)
@@ -159,7 +158,7 @@ actor A {
     let s = WithFeature.S()
     await s.nonisolatedAsyncConcurrent(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated instance method 'nonisolatedAsyncConcurrent' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent instance method 'nonisolatedAsyncConcurrent' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // S.nonisolatedAsyncCaller<A>(_:)
@@ -177,7 +176,7 @@ actor A {
     let s = WithoutFeature.S()
     await s.unspecifiedAsync(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated instance method 'unspecifiedAsync' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent instance method 'unspecifiedAsync' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // S.unspecifiedAsyncConcurrent<A>(_:)
@@ -187,7 +186,7 @@ actor A {
     let s = WithoutFeature.S()
     await s.unspecifiedAsyncConcurrent(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated instance method 'unspecifiedAsyncConcurrent' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent instance method 'unspecifiedAsyncConcurrent' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // S.unspecifiedAsyncCaller<A>(_:)
@@ -205,7 +204,7 @@ actor A {
     let s = WithoutFeature.S()
     await s.nonisolatedAsync(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated instance method 'nonisolatedAsync' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent instance method 'nonisolatedAsync' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // S.nonisolatedAsyncConcurrent<A>(_:)
@@ -215,7 +214,7 @@ actor A {
     let s = WithoutFeature.S()
     await s.nonisolatedAsyncConcurrent(ns)
     // expected-error @-1 {{sending 'self.ns' risks causing data races}}
-    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to nonisolated instance method 'nonisolatedAsyncConcurrent' risks causing data races between nonisolated and 'self'-isolated uses}}
+    // expected-note @-2 {{sending 'self'-isolated 'self.ns' to @concurrent instance method 'nonisolatedAsyncConcurrent' risks causing data races between @concurrent and 'self'-isolated uses}}
   }
 
   // CHECK-LABEL: // S.nonisolatedAsyncCaller<A>(_:)
diff --git a/test/Serialization/can-import-invalid-arch.swift b/test/Serialization/can-import-invalid-arch.swift
new file mode 100644
index 0000000000000..2d4e7bf45babf
--- /dev/null
+++ b/test/Serialization/can-import-invalid-arch.swift
@@ -0,0 +1,13 @@
+// RUN: %empty-directory(%t)
+// RUN: mkdir %t/Foo.swiftmodule
+// RUN: touch %t/Foo.swiftmodule/i387.swiftmodule
+// RUN: touch %t/Foo.swiftmodule/ppc65.swiftmodule
+// RUN: touch %t/Foo.swiftmodule/i387.swiftdoc
+// RUN: touch %t/Foo.swiftmodule/ppc65.swiftdoc
+// RUN: %target-swift-frontend %s -typecheck -I %t 2>&1 | %FileCheck %s -DTARGET_ARCHITECTURE=%module-target-triple
+
+// CHECK: {{.*}} warning: could not find module 'Foo' for target '[[TARGET_ARCHITECTURE]]'; found: {{ppc65, i387|i387, ppc65}}, at: {{.*}}Foo.swiftmodule
+
+#if canImport(Foo)
+  import Foo
+#endif
diff --git a/test/Serialization/clang-function-types-convention-c.swift b/test/Serialization/clang-function-types-convention-c.swift
new file mode 100644
index 0000000000000..0e1a9b2e9710a
--- /dev/null
+++ b/test/Serialization/clang-function-types-convention-c.swift
@@ -0,0 +1,21 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-module -o %t %S/Inputs/convention_c_function.swift
+// RUN: llvm-bcanalyzer %t/convention_c_function.swiftmodule | %FileCheck -check-prefix=CHECK-BCANALYZER %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-silgen -I %t %s | %FileCheck %s
+
+import convention_c_function
+
+// CHECK-BCANALYZER-LABEL: (INDEX_BLOCK):
+// CHECK-BCANALYZER: CLANG_TYPE_OFFSETS
+
+// Test that the assertion in SILDeclRef doesn't fail.
+
+// CHECK-LABEL: sil [ossa] @$s4main3baryyF : $@convention(thin) () -> () {
+// CHECK: %[[V0:.*]] = function_ref @$s4main3baryyFyycfU_To : $@convention(c) () -> ()
+// CHECK: %[[V1:.*]] = function_ref @$s21convention_c_function3foo2fnyyyXC_tF : $@convention(thin) (@convention(c) () -> ()) -> ()
+// CHECK: apply %[[V1]](%[[V0]]) : $@convention(thin) (@convention(c) () -> ()) -> ()
+
+public func bar() {
+  foo(fn : {})
+}
+
diff --git a/test/Serialization/clang-function-types.swift b/test/Serialization/clang-function-types.swift
index 61d0ff0a628be..01016e4ccc71d 100644
--- a/test/Serialization/clang-function-types.swift
+++ b/test/Serialization/clang-function-types.swift
@@ -25,5 +25,5 @@ func test2() {
 // CHECK-LABEL: sil public_external [canonical] @$s24def_clang_function_types17use_fp_internallyyyF
 // CHECK:         enum $Optional<@convention(c, cType: "struct ForwardInTypedefForFP2 *(*)(void)") () -> Optional<OpaquePointer>>, #Optional.none!enumelt
 // CHECK:         [[FN:%.*]] = function_ref @$s24def_clang_function_types9use_inout3argyxz_tlF : $@convention(thin) <τ_0_0> (@inout τ_0_0) -> ()
-// CHECK:         apply [[FN]]<(@convention(c, cType: "OpaqueTypedefForFP2 (*)(void)") () -> OpaquePointer?)?>
+// CHECK:         apply [[FN]]<Optional<@convention(c, cType: "struct ForwardInTypedefForFP2 *(*)(void)") () -> Optional<OpaquePointer>>>
 // CHECK-LABEL: } // end sil function '$s24def_clang_function_types17use_fp_internallyyyF'
diff --git a/test/Serialization/debug-scope.swift b/test/Serialization/debug-scope.swift
index cb0794ec1d425..48484d0a9fd6f 100644
--- a/test/Serialization/debug-scope.swift
+++ b/test/Serialization/debug-scope.swift
@@ -18,8 +18,8 @@ var funcReferringInlinedGeneric = specializedGenericInlined()
 
 // _alwaysEmitIntoClient with Onone
 // NOOPT: sil_scope [[SCOPE_ONE:[0-9]+]] { loc "{{.*}}def_debug.swift":21:13 parent @$s9def_debug10barGeneric_3sumxSayxG_xtSjRzlF : $@convention(thin) <τ_0_0 where τ_0_0 : Numeric> (@guaranteed Array<τ_0_0>, @in_guaranteed τ_0_0) -> @out τ_0_0 }
-// NOOPT: sil_scope [[SCOPE_TWO:[0-9]+]] { loc "{{.*}}def_debug.swift":22:9 parent [[SCOPE_ONE]] }
-// NOOPT: sil_scope {{[0-9]+}} { loc "{{.*}}def_debug.swift":22:16 parent [[SCOPE_ONE]] }
+// NOOPT-DAG: sil_scope [[SCOPE_TWO:[0-9]+]] { loc "{{.*}}def_debug.swift":22:9 parent [[SCOPE_ONE]] }
+// NOOPT-DAG: sil_scope {{[0-9]+}} { loc "{{.*}}def_debug.swift":22:16 parent [[SCOPE_ONE]] }
 // NOOPT: sil_scope [[SCOPE_THREE:[0-9]+]] { loc "{{.*}}def_debug.swift":23:5 parent [[SCOPE_TWO]] }
 // NOOPT: sil_scope {{[0-9]+}} { loc "{{.*}}def_debug.swift":23:14 parent [[SCOPE_THREE]] }
 let x = barGeneric([1,2], sum: 0)
diff --git a/test/Serialization/early-serialization.swift b/test/Serialization/early-serialization.swift
index b8bb3d41d1f80..d67ac94619640 100644
--- a/test/Serialization/early-serialization.swift
+++ b/test/Serialization/early-serialization.swift
@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -O -module-name Swift -module-link-name swiftCore -parse-as-library -parse-stdlib -emit-module %s -o %t/Swift.swiftmodule -enable-ossa-modules
+// RUN: %target-swift-frontend -emit-module -O -module-name Swift -module-link-name swiftCore -parse-as-library -parse-stdlib -emit-module %s -o %t/Swift.swiftmodule
 // RUN: %target-sil-opt -enable-sil-verify-all %t/Swift.swiftmodule -emit-sorted-sil -o - | %FileCheck %s
 
 // Test that early serialization works as expected:
diff --git a/test/Serialization/explicit_lifetime_dependence.swift b/test/Serialization/explicit_lifetime_dependence.swift
index 9232ef77523a9..f631a1f73815b 100644
--- a/test/Serialization/explicit_lifetime_dependence.swift
+++ b/test/Serialization/explicit_lifetime_dependence.swift
@@ -1,15 +1,15 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -o %t  %S/Inputs/def_explicit_lifetime_dependence.swift \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: -disable-lifetime-dependence-diagnostics
 
 // RUN: llvm-bcanalyzer %t/def_explicit_lifetime_dependence.swiftmodule 
 
 // RUN: %target-swift-frontend -module-name lifetime-dependence -emit-sil -I %t %s \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: | %FileCheck %s
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 import def_explicit_lifetime_dependence
 func testBasic() {
diff --git a/test/Serialization/extension-of-typealias.swift b/test/Serialization/extension-of-typealias.swift
index 7aa7d81197ffb..e440630c9265e 100644
--- a/test/Serialization/extension-of-typealias.swift
+++ b/test/Serialization/extension-of-typealias.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -module-name Library -o %t -D LIBRARY %s
 // RUN: %target-swift-ide-test -print-module -module-to-print=Library -I %t -source-filename=%s | %FileCheck %s
-// RUN: %target-swift-frontend -typecheck -I %t %s -verify
+// RUN: %target-swift-frontend -typecheck -I %t %s -verify -verify-ignore-unrelated
 
 // Check that base types of extensions are desugared. This isn't necessarily
 // the behavior we want long-term, but it's the behavior we need right now.
diff --git a/test/Serialization/failed-clang-module.swift b/test/Serialization/failed-clang-module.swift
index 09438bfdbe81f..59ecc07b7c354 100644
--- a/test/Serialization/failed-clang-module.swift
+++ b/test/Serialization/failed-clang-module.swift
@@ -13,7 +13,7 @@
 // RUN: %target-swift-frontend -emit-module %S/Inputs/SwiftModB.swift -module-name SwiftModB -F %t -o %t -module-cache-path %t/mcp
 
 // RUN: %target-swift-frontend -typecheck %s -I %t -module-cache-path %t/mcp
-// RUN: %target-swift-frontend -typecheck %s -Xcc -DFAIL -I %t -module-cache-path %t/mcp -show-diagnostics-after-fatal -verify -verify-ignore-unknown
+// RUN: %target-swift-frontend -typecheck %s -Xcc -DFAIL -I %t -module-cache-path %t/mcp -show-diagnostics-after-fatal -verify -verify-ignore-unrelated -verify-ignore-unknown
 
 import SwiftModB // expected-error {{missing required module}}
 _ = TyB() // expected-error {{cannot find 'TyB' in scope}}
diff --git a/test/Serialization/implicit_lifetime_dependence.swift b/test/Serialization/implicit_lifetime_dependence.swift
index aa08f650b1a10..7a36f50d883b6 100644
--- a/test/Serialization/implicit_lifetime_dependence.swift
+++ b/test/Serialization/implicit_lifetime_dependence.swift
@@ -1,15 +1,15 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -o %t  %S/Inputs/def_implicit_lifetime_dependence.swift \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: -disable-lifetime-dependence-diagnostics
 
 // RUN: llvm-bcanalyzer %t/def_implicit_lifetime_dependence.swiftmodule 
 
 // RUN: %target-swift-frontend -module-name lifetime-dependence -emit-sil -I %t %s \
-// RUN: -enable-experimental-feature LifetimeDependence \
+// RUN: -enable-experimental-feature Lifetimes \
 // RUN: | %FileCheck %s
 
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 import def_implicit_lifetime_dependence
 
diff --git a/test/Serialization/incremental-imports.swift b/test/Serialization/incremental-imports.swift
index 054d5d0690a52..9ee93576988f3 100644
--- a/test/Serialization/incremental-imports.swift
+++ b/test/Serialization/incremental-imports.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: cp %S/Inputs/incremental-imports/* %t
-// RUN: cp %t/A{-before,}.swift
+// RUN: cp %t/A-before.swift %t/A.swift
 
 
 // RUN: %target-swift-frontend -emit-module -module-name IncrementalImports -o %t/IncrementalImports~A.swiftmodule -primary-file %t/A.swift
@@ -17,7 +17,7 @@
 
 // RUN: %empty-directory(%t)
 // RUN: cp %S/Inputs/incremental-imports/* %t
-// RUN: cp %t/A{-after,}.swift
+// RUN: cp %t/A-after.swift %t/A.swift
 // RUN: %target-swift-frontend -emit-module -module-name IncrementalImports -o %t/IncrementalImports~A.swiftmodule -primary-file %t/A.swift
 // RUN: %target-swift-frontend -merge-modules -emit-module -module-name IncrementalImports -o %t/IncrementalImports.swiftmodule %t/IncrementalImports~A.swiftmodule
 
diff --git a/test/Serialization/isolated-params.swift b/test/Serialization/isolated-params.swift
index e13490ef3a2bb..0ddc325686192 100644
--- a/test/Serialization/isolated-params.swift
+++ b/test/Serialization/isolated-params.swift
@@ -10,8 +10,7 @@ import def_isolated
 
 func test(a: A, a2: isolated A, s: S) async {
   await s.f(a: a)
-  s.f(a: a) // expected-error{{expression is 'async' but is not marked with 'await'}}
-  // expected-note@-1{{calls to instance method 'f(a:)' from outside of its actor context are implicitly asynchronous}}
+  s.f(a: a) // expected-error{{actor-isolated instance method 'f(a:)' cannot be called from outside of the actor}} {{3-3=await }}
 
   s.f(a: a2)
 }
diff --git a/test/Serialization/isolated_conformance.swift b/test/Serialization/isolated_conformance.swift
index beeb48aa1068a..d7e7701313c78 100644
--- a/test/Serialization/isolated_conformance.swift
+++ b/test/Serialization/isolated_conformance.swift
@@ -1,16 +1,18 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -target %target-swift-5.1-abi-triple -swift-version 6 -enable-experimental-feature IsolatedConformances -o %t/def_isolated_conformance.swiftmodule %S/Inputs/def_isolated_conformance.swift
+// RUN: %target-swift-frontend -emit-module -target %target-swift-5.1-abi-triple -swift-version 6 -o %t/def_isolated_conformance.swiftmodule %S/Inputs/def_isolated_conformance.swift -default-isolation=MainActor
 
-// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 6 -enable-experimental-feature IsolatedConformances %s -I %t
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.1-abi-triple -swift-version 6 %s -I %t
 
-// REQUIRES: swift_feature_IsolatedConformances
 // REQUIRES: concurrency
 
 import def_isolated_conformance
 
 func acceptMyProtocol(_: some MyProtocol) { }
+func acceptOtherProtocol(_: some MyProtocol) { }
 
 nonisolated func f(mc: MyClass) {
   acceptMyProtocol(mc)
   // expected-error@-1{{main actor-isolated conformance of 'MyClass' to 'MyProtocol' cannot be used in nonisolated context}}
+  acceptOtherProtocol(mc)
+  // expected-error@-1{{main actor-isolated conformance of 'MyClass' to 'MyProtocol' cannot be used in nonisolated context}}
 }
diff --git a/test/Serialization/lazy-typecheck.swift b/test/Serialization/lazy-typecheck.swift
index 9a219e7ced3c9..b07f42d263f6c 100644
--- a/test/Serialization/lazy-typecheck.swift
+++ b/test/Serialization/lazy-typecheck.swift
@@ -4,19 +4,19 @@
 
 // (1) Build the module normally and verify that a client can deserialize it and use its public declarations.
 // RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -enable-library-evolution -parse-as-library -package-name Package -DFLAG -emit-module -emit-module-path %t/baseline/lazy_typecheck.swiftmodule
-// RUN: %target-swift-frontend -package-name Package -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -DFLAG -I %t/baseline
+// RUN: %target-swift-frontend -package-name Package -typecheck -verify -verify-ignore-unrelated %S/../Inputs/lazy_typecheck_client.swift -DFLAG -I %t/baseline
 
 // (2) Verify that a module built with -experimental-lazy-typecheck, -experimental-skip-all-function-bodies,
 //     and -experimental-skip-non-exportable-decls can be used by the same client as in (1).
 // RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -enable-library-evolution -parse-as-library -package-name Package -DFLAG -emit-module -emit-module-path %t/lazy-skip-all/lazy_typecheck.swiftmodule -debug-forbid-typecheck-prefix NoTypecheck -experimental-lazy-typecheck -experimental-skip-all-function-bodies -experimental-skip-non-exportable-decls
-// RUN: %target-swift-frontend -package-name Package -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -DFLAG -I %t/lazy-skip-all
+// RUN: %target-swift-frontend -package-name Package -typecheck -verify -verify-ignore-unrelated %S/../Inputs/lazy_typecheck_client.swift -DFLAG -I %t/lazy-skip-all
 
 // (2a) Verify that -experimental-lazy-typecheck and -experimental-skip-non-exportable-decls do not require
 // -enable-library-evolution if -experimental-skip-all-function-bodies is specified.
 // RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -parse-as-library -package-name Package -DFLAG -emit-module -emit-module-path %t/lazy-skip-all-non-resilient/lazy_typecheck.swiftmodule -debug-forbid-typecheck-prefix NoTypecheck -experimental-lazy-typecheck -experimental-skip-all-function-bodies -experimental-skip-non-exportable-decls
-// RUN: %target-swift-frontend -package-name Package -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -DFLAG -I %t/lazy-skip-all-non-resilient
+// RUN: %target-swift-frontend -package-name Package -typecheck -verify -verify-ignore-unrelated %S/../Inputs/lazy_typecheck_client.swift -DFLAG -I %t/lazy-skip-all-non-resilient
 
 // (3) Verify that a module built with -experimental-lazy-typecheck, -experimental-skip-non-inlinable-function-bodies,
 //     and -experimental-skip-non-exportable-decls can be used by the same client as in (1).
 // RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -enable-library-evolution -parse-as-library -package-name Package -DFLAG -emit-module -emit-module-path %t/lazy-skip-non-inlinable/lazy_typecheck.swiftmodule -debug-forbid-typecheck-prefix NoTypecheck -experimental-lazy-typecheck -experimental-skip-non-inlinable-function-bodies -experimental-skip-non-exportable-decls
-// RUN: %target-swift-frontend -package-name Package -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -DFLAG -I %t/lazy-skip-non-inlinable
+// RUN: %target-swift-frontend -package-name Package -typecheck -verify -verify-ignore-unrelated %S/../Inputs/lazy_typecheck_client.swift -DFLAG -I %t/lazy-skip-non-inlinable
diff --git a/test/Serialization/lifetime_dependence.swift b/test/Serialization/lifetime_dependence.swift
new file mode 100644
index 0000000000000..1240e3328c3c8
--- /dev/null
+++ b/test/Serialization/lifetime_dependence.swift
@@ -0,0 +1,17 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -enable-builtin-module -enable-experimental-feature Lifetimes -enable-experimental-feature AddressableTypes -enable-experimental-feature AddressableParameters -module-name lifetime_dependence_ref -o %t %S/Inputs/lifetime_dependence.swift
+// RUN: %target-swift-frontend -I %t -emit-ir %s -verify | %FileCheck %s
+
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_AddressableTypes
+// REQUIRES: swift_feature_AddressableParameters
+
+import lifetime_dependence_ref
+
+public func foo() {
+  let x = 123
+  let y = Ref(x)
+
+  // CHECK: print
+  print(y[])
+}
diff --git a/test/Serialization/lifetime_dependence_enums.swift b/test/Serialization/lifetime_dependence_enums.swift
new file mode 100644
index 0000000000000..505ff8f4a1568
--- /dev/null
+++ b/test/Serialization/lifetime_dependence_enums.swift
@@ -0,0 +1,42 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -o %t  %S/Inputs/def_lifetime_dependence_enums.swift 
+
+// RUN: llvm-bcanalyzer %t/def_lifetime_dependence_enums.swiftmodule 
+
+// RUN: %target-swift-frontend -c -module-name lifetime-dependence-enums -Xllvm -sil-print-after=EarlyPerfInliner -O -I %t %s \
+// RUN: -enable-experimental-feature Lifetimes -o /dev/null 2>&1 | %FileCheck %s
+
+// REQUIRES: swift_feature_Lifetimes
+
+import def_lifetime_dependence_enums 
+
+@inline(__always)
+public func testSome<T : OptionalType>(_ t: T, _ w: T.Wrapped) -> T {
+  return T.self.some(w)
+}
+
+@inline(__always)
+public func testSomePair<T : OptionalType>(_ t: T, _ w: T.Wrapped) -> T {
+  return T.self.somePair(w, w)
+}
+
+// CHECK-LABEL: sil [ossa] @$s4main5test1yQr29def_lifetime_dependence_enums12FakeOptionalOyxG_xtlF : 
+// Match the second instance of EarlyPerfInliner
+// CHECK-LABEL: sil [ossa] @$s4main5test1yQr29def_lifetime_dependence_enums12FakeOptionalOyxG_xtlF : 
+// CHECK: [[FUNC:%.*]] = function_ref @$s29def_lifetime_dependence_enums12FakeOptionalO4someyACyxGxcAEmlF : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable, τ_0_0 : ~Escapable> (@in τ_0_0, @thin FakeOptional<τ_0_0>.Type) -> @lifetime(copy 0) @out FakeOptional<τ_0_0>
+// CHECK: apply [[FUNC]]<W>({{.*}}) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable, τ_0_0 : ~Escapable> (@in τ_0_0, @thin FakeOptional<τ_0_0>.Type) -> @lifetime(copy 0) @out FakeOptional<τ_0_0>
+// CHECK-LABEL: } // end sil function '$s4main5test1yQr29def_lifetime_dependence_enums12FakeOptionalOyxG_xtlF'
+public func test1<W>(_ f: FakeOptional<W>, _ w: FakeOptional<W>.Wrapped) -> some OptionalType {
+  return testSome(f, w)
+}
+
+// CHECK-LABEL: sil [ossa] @$s4main5test2yQr29def_lifetime_dependence_enums12FakeOptionalOyxG_xtlF : 
+// Match the second instance of EarlyPerfInliner
+// CHECK-LABEL: sil [ossa] @$s4main5test2yQr29def_lifetime_dependence_enums12FakeOptionalOyxG_xtlF : 
+// CHECK:   [[FUNC:%.*]] = function_ref @$s29def_lifetime_dependence_enums12FakeOptionalO8somePairyACyxGx_xtcAEmlF : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable, τ_0_0 : ~Escapable> (@in τ_0_0, @in τ_0_0, @thin FakeOptional<τ_0_0>.Type) -> @lifetime(copy 0, copy 1) @out FakeOptional<τ_0_0> // user: %13
+// CHECK:   apply [[FUNC]]<W>({{.*}}) : $@convention(method) <τ_0_0 where τ_0_0 : ~Copyable, τ_0_0 : ~Escapable> (@in τ_0_0, @in τ_0_0, @thin FakeOptional<τ_0_0>.Type) -> @lifetime(copy 0, copy 1) @out FakeOptional<τ_0_0>
+// CHECK-LABEL: } // end sil function '$s4main5test2yQr29def_lifetime_dependence_enums12FakeOptionalOyxG_xtlF'
+public func test2<W>(_ f: FakeOptional<W>, _ w: FakeOptional<W>.Wrapped) -> some OptionalType {
+  return testSomePair(f, w)
+}
+
diff --git a/test/Serialization/non_escapable_subst_test.swift b/test/Serialization/non_escapable_subst_test.swift
new file mode 100644
index 0000000000000..f69ea90b0e3e8
--- /dev/null
+++ b/test/Serialization/non_escapable_subst_test.swift
@@ -0,0 +1,26 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -o %t  %S/Inputs/ne_types.swift \
+// RUN: -enable-experimental-feature Lifetimes \
+// RUN: -enable-experimental-feature AddressableTypes \
+// RUN: -enable-library-evolution \
+// RUN: -emit-module-path %t/ne_types.swiftmodule 
+
+// RUN: %target-swift-frontend -emit-silgen -I %t %s \
+// RUN: -enable-experimental-feature Lifetimes
+
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_AddressableTypes
+
+import ne_types
+
+// Ensure no memory crashes during SILGen
+
+struct NonEscapableFrameworkThingTests {
+  func example() async throws {
+    let ptr = UnsafeMutableRawBufferPointer.allocate(byteCount: 40, alignment: 1)
+    defer { ptr.deallocate() }
+    var something = Something(ptr: ptr)
+    var mutableView = something.mutableView(of: Float32.self)
+    var mutableSpan = mutableView.mutableSpan
+  }
+}
diff --git a/test/Serialization/objc_method_table.swift b/test/Serialization/objc_method_table.swift
index e81fede4183fc..87f445bd0506b 100644
--- a/test/Serialization/objc_method_table.swift
+++ b/test/Serialization/objc_method_table.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -disable-objc-attr-requires-foundation-module -o %t %S/Inputs/objc_method_decls.swift
 // RUN: llvm-bcanalyzer %t/objc_method_decls.swiftmodule | %FileCheck %s
-// RUN: %target-swift-frontend -typecheck -disable-objc-attr-requires-foundation-module -I %t %s -verify
+// RUN: %target-swift-frontend -typecheck -disable-objc-attr-requires-foundation-module -I %t %s -verify -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/Serialization/plugin_search_option_prefixing.swift b/test/Serialization/plugin_search_option_prefixing.swift
new file mode 100644
index 0000000000000..11df53ab13e2f
--- /dev/null
+++ b/test/Serialization/plugin_search_option_prefixing.swift
@@ -0,0 +1,63 @@
+// REQUIRES: swift_swift_parser
+
+/// Test loading dependencies that has macros.
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+/// Build macros.
+// RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroOne) -module-name=MacroOne %t/macro-1.swift
+// RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroTwo) -module-name=MacroTwo %t/macro-2.swift
+
+// RUN: %target-swift-frontend -emit-module %t/test.swift -module-name Test -o %t/Test.swiftmodule \
+// RUN:   -swift-version 5 -external-plugin-path %t#%swift-plugin-server -package-name Test \
+// RUN:   -plugin-path %swift-plugin-dir -prefix-serialized-debugging-options \
+// RUN:   -load-plugin-library %t/%target-library-name(MacroOne) \
+// RUN:   -debug-prefix-map %t=/externalsearchpath \
+// RUN:   -debug-prefix-map %swift-plugin-server=/externalserverpath \
+// RUN:   -debug-prefix-map %swift-plugin-dir=/plugindir
+// RUN: llvm-bcanalyzer -dump %t/Test.swiftmodule | %FileCheck %s
+
+// CHECK: <PLUGIN_SEARCH_OPTION abbrevid=8 op0=1/> blob data = '/externalsearchpath#/externalserverpath'
+// CHECK: <PLUGIN_SEARCH_OPTION abbrevid=8 op0=0/> blob data = '/plugindir'
+// CHECK: <PLUGIN_SEARCH_OPTION abbrevid=8 op0=2/> blob data = '/externalsearchpath/{{(lib)?}}MacroOne
+
+//--- macro-1.swift
+import SwiftSyntax
+@_spi(ExperimentalLanguageFeature) import SwiftSyntaxMacros
+
+public struct AssertMacro: ExpressionMacro {
+  public static func expansion(
+    of macro: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) -> ExprSyntax {
+    guard let argument = macro.arguments.first?.expression else {
+      fatalError("boom")
+    }
+
+    return "assert(\(argument))"
+  }
+}
+
+//--- macro-2.swift
+import SwiftSyntax
+@_spi(ExperimentalLanguageFeature) import SwiftSyntaxMacros
+
+public struct StringifyMacro: ExpressionMacro {
+  public static func expansion(
+    of macro: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) -> ExprSyntax {
+    guard let argument = macro.arguments.first?.expression else {
+      fatalError("boom")
+    }
+
+    return "(\(argument), \(StringLiteralExprSyntax(content: argument.description)))"
+  }
+}
+
+//--- test.swift
+import Swift
+@freestanding(expression) public macro assert(_: Bool) = #externalMacro(module: "MacroOne", type: "AssertMacro")
+@freestanding(expression) public macro assert_2(_: Bool) = #externalMacro(module: "MacroOne", type: "AssertMacro")
+@freestanding(expression) public macro stringify<T>(_ value: T) -> (T, String) = #externalMacro(module: "MacroTwo", type: "StringifyMacro")
+@freestanding(expression) public macro stringify_2<T>(_ value: T) -> (T, String) = #externalMacro(module: "MacroTwo", type: "StringifyMacro")
diff --git a/test/Serialization/property_wrappers.swift b/test/Serialization/property_wrappers.swift
index 3ea9f8fcaad2e..877009b78bbf3 100644
--- a/test/Serialization/property_wrappers.swift
+++ b/test/Serialization/property_wrappers.swift
@@ -2,7 +2,7 @@
 // RUN: %empty-directory(%t-scratch)
 // RUN: %target-swift-frontend -emit-module -o %t-scratch/def_property_wrappers~partial.swiftmodule -primary-file %S/Inputs/def_property_wrappers.swift -module-name def_property_wrappers -enable-testing
 // RUN: %target-swift-frontend -merge-modules -emit-module -parse-as-library -enable-testing %t-scratch/def_property_wrappers~partial.swiftmodule -module-name def_property_wrappers -o %t/def_property_wrappers.swiftmodule
-// RUN: %target-swift-frontend -typecheck -I%t -verify %s -verify-ignore-unknown
+// RUN: %target-swift-frontend -typecheck -I%t -verify -verify-ignore-unrelated %s -verify-ignore-unknown
 
 @testable import def_property_wrappers
 
diff --git a/test/Serialization/raw_layout.swift b/test/Serialization/raw_layout.swift
index 065bdde602768..5ec4d97fc614c 100644
--- a/test/Serialization/raw_layout.swift
+++ b/test/Serialization/raw_layout.swift
@@ -18,8 +18,8 @@ import RawLayoutCXX
 // CHECK-SAME:  , {{i64|i32}} 1
 // stride
 // CHECK-SAME:  , {{i64|i32}} 1
-// flags: not copyable, not bitwise takable, not pod, not inline
-// CHECK-SAME:  , i32 9633792
+// flags: addressable for dependencies, not copyable, not bitwise takable, not pod, not inline
+// CHECK-SAME:  , i32 43188224
 struct WeirdCXXTypeCell: ~Copyable {
   let cell: CellThatMovesLike<NonBitwiseTakableCXXType>
 }
diff --git a/test/Serialization/search-paths.swift b/test/Serialization/search-paths.swift
index 54b61e50bc0e8..3f3cd9ce90a72 100644
--- a/test/Serialization/search-paths.swift
+++ b/test/Serialization/search-paths.swift
@@ -5,7 +5,7 @@
 // RUN: %target-swift-frontend -emit-module -o %t/Frameworks/has_alias.framework/Modules/has_alias.swiftmodule/%target-swiftmodule-name %S/Inputs/alias.swift -module-name has_alias
 
 // RUN: %target-swift-frontend -emit-module -o %t -I %t/secret -F %t/Frameworks -Fsystem %t/SystemFrameworks -parse-as-library %S/Inputs/has_xref.swift
-// RUN: %target-swift-frontend %s -typecheck -I %t -verify -show-diagnostics-after-fatal
+// RUN: %target-swift-frontend %s -typecheck -I %t -verify -verify-ignore-unrelated -show-diagnostics-after-fatal
 
 // Try again, treating has_xref as a main file to force serialization to occur.
 // RUN: %target-swift-frontend -emit-module -o %t -I %t/secret -F %t/Frameworks -Fsystem %t/SystemFrameworks %S/Inputs/has_xref.swift
@@ -19,7 +19,7 @@
 
 // Make sure -no-serialize-debugging-options has the desired effect.
 // RUN: %target-swift-frontend -emit-module -o %t -I %t/secret -F %t/Frameworks -Fsystem %t/SystemFrameworks -parse-as-library %S/Inputs/has_xref.swift -application-extension -no-serialize-debugging-options
-// RUN: %target-swift-frontend %s -typecheck -I %t -verify -show-diagnostics-after-fatal
+// RUN: %target-swift-frontend %s -typecheck -I %t -verify -verify-ignore-unrelated -show-diagnostics-after-fatal
 
 // Make sure we don't end up with duplicate search paths.
 // RUN: %target-swiftc_driver -emit-module -o %t/has_xref.swiftmodule -I %t/secret -F %t/Frameworks -Fsystem %t/SystemFrameworks -parse-as-library %S/Inputs/has_xref.swift %S/../Inputs/empty.swift -Xfrontend -serialize-debugging-options
diff --git a/test/Serialization/shadowed-class-vs-protocol.swift b/test/Serialization/shadowed-class-vs-protocol.swift
new file mode 100644
index 0000000000000..04d3004233ae8
--- /dev/null
+++ b/test/Serialization/shadowed-class-vs-protocol.swift
@@ -0,0 +1,50 @@
+/// Ensure cross references to shadowed decls take into account the shadowing
+/// after the custom deserialization filtering.
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// REQUIRES: objc_interop
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   %t/SwiftLib.swift -I %t -emit-module-path %t/SwiftLib.swiftmodule
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) \
+// RUN:   -typecheck %t/Client.swift -I %t
+
+//--- module.modulemap
+module RootLib {
+  header "RootLib.h"
+}
+
+module MiddleLib {
+  header "MiddleLib.h"
+  export *
+}
+
+//--- RootLib.h
+__attribute__((swift_name("ShadowedProtocol")))
+@protocol Shadowed
+@end
+
+//--- MiddleLib.h
+@import Foundation;
+#include "RootLib.h"
+
+@interface Shadowed: NSObject <Shadowed>
+@end
+
+//--- SwiftLib.swift
+import MiddleLib
+
+public func funcRef() -> Shadowed { fatalError() }
+
+extension Shadowed {
+    public func method() -> Shadowed { fatalError() }
+}
+
+//--- Client.swift
+import SwiftLib
+
+@inlinable
+public func bar() {
+    let _ = funcRef().method()
+}
diff --git a/test/Serialization/transitive_conformances_and_cgfloat_double.swift b/test/Serialization/transitive_conformances_and_cgfloat_double.swift
new file mode 100644
index 0000000000000..c91fcb5661544
--- /dev/null
+++ b/test/Serialization/transitive_conformances_and_cgfloat_double.swift
@@ -0,0 +1,32 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-module %s -o %t
+
+// REQUIRES: objc_interop
+
+// rdar://153461854
+
+import CoreGraphics
+
+@resultBuilder
+public struct Builder {
+  public static func buildBlock<T1>(_ t1: T1) -> (T1) {
+    return (t1)
+  }
+}
+
+protocol P {
+}
+
+struct Proxy: P {
+  let to: (CGFloat?) -> Void
+}
+
+struct Test {
+  @Builder var proxy: some P {
+    Proxy { point in
+      if let point {
+        let _: SIMD2<Double>? = SIMD2(point, point)
+      }
+    }
+  }
+}
+
diff --git a/test/Serialization/using.swift b/test/Serialization/using.swift
new file mode 100644
index 0000000000000..634337f30d886
--- /dev/null
+++ b/test/Serialization/using.swift
@@ -0,0 +1,9 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -o %t %s -module-name Using -enable-experimental-feature DefaultIsolationPerFile
+// RUN: %target-swift-frontend -typecheck -I %t %s -module-name main -DMAIN -verify -enable-experimental-feature DefaultIsolationPerFile
+
+// REQUIRES: swift_feature_DefaultIsolationPerFile
+
+using @MainActor
+
+public func test() {}
diff --git a/test/Serialization/value_generics.swift b/test/Serialization/value_generics.swift
index 3a2cfbc96c000..72f036e38feb1 100644
--- a/test/Serialization/value_generics.swift
+++ b/test/Serialization/value_generics.swift
@@ -1,9 +1,8 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend %s -emit-module -enable-experimental-feature RawLayout -enable-experimental-feature InlineArrayTypeSugar -disable-availability-checking -parse-as-library -o %t
+// RUN: %target-swift-frontend %s -emit-module -enable-experimental-feature RawLayout -disable-availability-checking -parse-as-library -o %t
 // RUN: %target-sil-opt -enable-sil-verify-all %t/value_generics.swiftmodule -o - | %FileCheck %s
 
 // REQUIRES: swift_feature_RawLayout
-// REQUIRES: swift_feature_InlineArrayTypeSugar
 
 // CHECK: @_rawLayout(likeArrayOf: Element, count: Count) struct Vector<Element, let Count : Int> : ~Copyable where Element : ~Copyable {
 @_rawLayout(likeArrayOf: Element, count: Count)
@@ -22,5 +21,5 @@ extension Vector where Count == 2 {
 // CHECK: func something<let N : Int>(_: borrowing Vector<Int, N>)
 func something<let N: Int>(_: borrowing Vector<Int, N>) {}
 
-// CHECK: func hello(_: [4 x Int])
-func hello(_: [4 x Int]) {}
+// CHECK: func hello(_: [4 of Int])
+func hello(_: [4 of Int]) {}
diff --git a/test/SourceKit/CodeComplete/complete_checkdeps_swiftmodule.swift b/test/SourceKit/CodeComplete/complete_checkdeps_swiftmodule.swift
index b28194ea22950..048fc5d9cdba9 100644
--- a/test/SourceKit/CodeComplete/complete_checkdeps_swiftmodule.swift
+++ b/test/SourceKit/CodeComplete/complete_checkdeps_swiftmodule.swift
@@ -37,7 +37,7 @@ func foo() {
 
 // RUN:   -shell -- echo '### Modify framework (s)' == \
 // RUN:   -shell --  %target-swift-frontend -emit-module -module-name SwiftFW -o %t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule/%target-swiftmodule-name $INPUT_DIR/SwiftFW_src_mod/Funcs.swift == \
-// RUN    -shell -- touch -t 210001010101 %t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule/%target-swiftmodule-name == \
+// RUN:    -shell -- touch -t 210001010101 %t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule/%target-swiftmodule-name == \
 // RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} == \
 
 // RUN:   -shell -- echo '### Fast completion' == \
diff --git a/test/SourceKit/CodeComplete/complete_filter_rules.swift b/test/SourceKit/CodeComplete/complete_filter_rules.swift
index 437ac7079b195..beb965ba5343d 100644
--- a/test/SourceKit/CodeComplete/complete_filter_rules.swift
+++ b/test/SourceKit/CodeComplete/complete_filter_rules.swift
@@ -216,7 +216,7 @@ func testHideDesc2() {
 
 // RUN: %complete-test -filter-rules=%S/Inputs/filter-rules/showDesc.json -tok=SHOW_DESC_2 %s -- -F %S/../Inputs/libIDE-mock-sdk | %FileCheck %s -check-prefix=SHOW_DESC_2
 // RUN: %complete-test -filter-rules=%S/Inputs/filter-rules/showDesc.json -tok=SHOW_DESC_3 %s -- -F %S/../Inputs/libIDE-mock-sdk | %FileCheck %s -check-prefix=SHOW_DESC_2
-func testHideDesc2() {
+func testShowDesc2() {
   struct Local {
     subscript(_: Int) -> Int { return 0 }
     subscript(_: Float) -> Float { return 0.0 }
diff --git a/test/SourceKit/CodeComplete/complete_fuzzy.swift b/test/SourceKit/CodeComplete/complete_fuzzy.swift
index 6f9c03f84f615..5b9dc8ad83c63 100644
--- a/test/SourceKit/CodeComplete/complete_fuzzy.swift
+++ b/test/SourceKit/CodeComplete/complete_fuzzy.swift
@@ -48,7 +48,7 @@ func test3() {
 
 // RUN: %complete-test %s -group=stems -no-fuzz -tok=S1_QUAL_1 | %FileCheck %s -check-prefix=S1_QUAL_1_PREFIX
 // RUN: %complete-test %s -group=stems -fuzz -tok=S1_QUAL_1 | %FileCheck %s -check-prefix=S1_QUAL_1_FUZZ
-func test3() {
+func test4() {
   #^S1_QUAL_1,foo,bar,tast,footast^#
 // S1_QUAL_1_PREFIX-LABEL: Results for filterText: foo [
 // S1_QUAL_1_PREFIX-NEXT:    fooBar:
diff --git a/test/SourceKit/CodeComplete/complete_optionalmethod.swift.response b/test/SourceKit/CodeComplete/complete_optionalmethod.swift.response
index 444b43b8fcfe6..7aa522f70c69b 100644
--- a/test/SourceKit/CodeComplete/complete_optionalmethod.swift.response
+++ b/test/SourceKit/CodeComplete/complete_optionalmethod.swift.response
@@ -16,7 +16,7 @@
       key.kind: source.lang.swift.keyword,
       key.name: "self",
       key.description: "self",
-      key.typename: "T",
+      key.typename: "Proto",
       key.context: source.codecompletion.context.thisclass,
       key.typerelation: source.codecompletion.typerelation.unknown,
       key.num_bytes_to_erase: 0,
diff --git a/test/SourceKit/CodeComplete/complete_sort_order.swift b/test/SourceKit/CodeComplete/complete_sort_order.swift
index 90adec76d01ef..0c79938cb7e31 100644
--- a/test/SourceKit/CodeComplete/complete_sort_order.swift
+++ b/test/SourceKit/CodeComplete/complete_sort_order.swift
@@ -156,7 +156,7 @@ func test4(x: Int) {
 
 // Top 3 with type matching
 // RUN: %complete-test -top=3 -tok=EXPR_3 %s | %FileCheck %s -check-prefix=EXPR_TOP_3_TYPE_MATCH
-func test4(x: Int) {
+func test4b(x: Int) {
   let y: String = ""
   let z: String = y
   let zzz = x
diff --git a/test/SourceKit/CodeComplete/issue-80985.swift b/test/SourceKit/CodeComplete/issue-80985.swift
new file mode 100644
index 0000000000000..de7002fe44519
--- /dev/null
+++ b/test/SourceKit/CodeComplete/issue-80985.swift
@@ -0,0 +1,13 @@
+// https://github.com/swiftlang/swift/issues/80985
+struct S<T> {
+  func foo<U>(_ fn: (T) -> U) -> S<U> { fatalError() }
+}
+
+func foo(xs: S<(Int, Int)>) {
+  _ = {
+    let y = xs
+      .foo{ $1 }
+      .foo{ $0 }
+    // RUN: %sourcekitd-test -req=complete -pos=%(line-1):11 %s -- %s
+  }
+}
diff --git a/test/SourceKit/CodeComplete/pr83662.swift b/test/SourceKit/CodeComplete/pr83662.swift
new file mode 100644
index 0000000000000..999c9686a92d6
--- /dev/null
+++ b/test/SourceKit/CodeComplete/pr83662.swift
@@ -0,0 +1,7 @@
+// Make sure we don't crash
+struct S {
+  init?() {
+    return nil
+    // RUN: %sourcekitd-test -req=complete.open -pos=%(line-1):12 %s -- %s
+  }
+}
diff --git a/test/SourceKit/CodeExpand/code-expand.swift b/test/SourceKit/CodeExpand/code-expand.swift
index 61a40870d8f73..14d3f33ea0817 100644
--- a/test/SourceKit/CodeExpand/code-expand.swift
+++ b/test/SourceKit/CodeExpand/code-expand.swift
@@ -25,6 +25,10 @@ await foo(x: <#T##() -> Void#>)
 // CHECK-NEXT: <#code#>
 // CHECK-NEXT: }
 
+foo(bar(<#T##() -> Void#>))
+// CHECK:      foo(bar({
+// CHECK-NEXT: <#code#>
+// CHECK-NEXT: }))
 
 anArr.indexOfObjectPassingTest(<#T##predicate: ((AnyObject!, Int, UnsafePointer<ObjCBool>) -> Bool)?##((AnyObject!, Int, UnsafePointer<ObjCBool>) -> Bool)?#>)
 // CHECK:      anArr.indexOfObjectPassingTest { <#AnyObject!#>, <#Int#>, <#UnsafePointer<ObjCBool>#> in
@@ -273,3 +277,61 @@ expandClosureWithInternalParameterNames {
 // CHECK: withtrail { a, b in
 // CHECK-NEXT: <#code#>
 }
+
+// CHECK-LABEL: func expandMacro()
+func expandMacro() {
+  #foo(<#T##() -> Int#>)
+  // CHECK:      #foo {
+  // CHECK-NEXT:   <#code#>
+  // CHECK-NEXT: }
+
+  #foo(bar: <#T##() -> ()#>)
+  // CHECK:      #foo {
+  // CHECK-NEXT:   <#code#>
+  // CHECK-NEXT: }
+
+  #foo(bar: <#T##() -> Int#>, baz: <#T##() -> ()#>)
+  // CHECK:      #foo {
+  // CHECK-NEXT:   <#code#>
+  // CHECK-NEXT: } baz: {
+  // CHECK-NEXT:   <#code#>
+  // CHECK-NEXT: }
+}
+
+// CHECK-LABEL: struct ExpandDeclMacro
+struct ExpandDeclMacro {
+  #foo(<#T##() -> ()#>)
+  // CHECK:      #foo {
+  // CHECK-NEXT:   <#code#>
+  // CHECK-NEXT: }
+
+  #foo(bar(<#T##() -> ()#>))
+  // CHECK:      #foo(bar({
+  // CHECK-NEXT:   <#code#>
+  // CHECK-NEXT: }))
+
+  #foo(#bar(<#T##() -> ()#>))
+  // CHECK:      #foo(#bar({
+  // CHECK-NEXT:   <#code#>
+  // CHECK-NEXT: }))
+}
+
+@Foo(<#Int#>)
+func testDeclAttr1() {}
+// CHECK: @Foo(<#Int#>)
+// CHECK-NEXT: func testDeclAttr1() {}
+
+@Foo(<#T##() -> ()#>)
+func testDeclAttr2() {}
+// CHECK:      @Foo({
+// CHECK-NEXT:   <#code#>
+// CHECK-NEXT: })
+// CHECK-NEXT: func testDeclAttr2() {}
+
+func testTypeAttr1(x: @Foo(<#Int#>) String) {}
+// CHECK: func testTypeAttr1(x: @Foo(<#Int#>) String) {}
+
+func testTypeAttr2(x: @Foo(<#T##() -> ()#>) Int) {}
+// CHECK: func testTypeAttr2(x: @Foo({
+// CHECK-NEXT:   <#code#>
+// CHECK-NEXT: }) Int) {}
diff --git a/test/SourceKit/CursorInfo/cursor_doc_comment_from_clang_safe_wrapper.swift b/test/SourceKit/CursorInfo/cursor_doc_comment_from_clang_safe_wrapper.swift
new file mode 100644
index 0000000000000..078d8a16583f1
--- /dev/null
+++ b/test/SourceKit/CursorInfo/cursor_doc_comment_from_clang_safe_wrapper.swift
@@ -0,0 +1,105 @@
+// REQUIRES: swift_feature_SafeInteropWrappers
+
+// RUN: %empty-directory(%t)
+// RUN: split-file --leading-lines %s %t
+
+//--- header.h
+
+/** This comment contains `markup`.
+ *
+ * - And a list
+ */
+void testCDecl(const int * __attribute__((__counted_by__(len))) __attribute__((noescape)) p, int len);
+
+//--- module.modulemap
+
+module MyClangModule { header "header.h" }
+
+//--- test.swift
+
+import MyClangModule
+
+func test(_ s: Span<CInt>) {
+  // RUN: %sourcekitd-test -req=cursor -pos=%(line + 1):4 -req-opts=retrieve_symbol_graph=1 %s -- %s -I %t -enable-experimental-feature SafeInteropWrappers | %FileCheck %s
+  testCDecl(s)
+}
+
+// CHECK-LABEL: DOC COMMENT
+// CHECK: This comment contains `markup`.
+// CHECK: - And a list
+// CHECK-LABEL: DOC COMMENT XML
+// CHECK: <Function file="@__swiftmacro_So9testCDecl15_SwiftifyImportfMp_.swift" line="6" column="134"><Name>testCDecl(_:)</Name><USR>s:SC9testCDeclyys4SpanVys5Int32VGF</USR><Declaration>@available(visionOS 1.0, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+// CHECK-NEXT: public func testCDecl(_ p: Span&lt;Int32&gt;)</Declaration><CommentParts><Abstract><Para>This comment contains <codeVoice>markup</codeVoice>. *</Para></Abstract><Discussion><List-Bullet><Item><List-Bullet><Item><Para>And a list</Para></Item></List-Bullet></Item></List-Bullet><Para>This is an auto-generated wrapper for safer interop</Para></Discussion></CommentParts></Function>
+
+// CHECK-LABEL: SYMBOL GRAPH BEGIN
+// CHECK:      "docComment": {
+// CHECK-NEXT:   "lines": [
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "range": {
+// CHECK-NEXT:         "end": {
+// CHECK-NEXT:           "character": 35,
+// CHECK-NEXT:           "line": 0
+// CHECK-NEXT:         },
+// CHECK-NEXT:         "start": {
+// CHECK-NEXT:           "character": 4,
+// CHECK-NEXT:           "line": 0
+// CHECK-NEXT:         }
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "text": "This comment contains `markup`."
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "range": {
+// CHECK-NEXT:         "end": {
+// CHECK-NEXT:           "character": 2,
+// CHECK-NEXT:           "line": 1
+// CHECK-NEXT:         },
+// CHECK-NEXT:         "start": {
+// CHECK-NEXT:           "character": 1,
+// CHECK-NEXT:           "line": 1
+// CHECK-NEXT:         }
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "text": "*"
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "range": {
+// CHECK-NEXT:         "end": {
+// CHECK-NEXT:           "character": 15,
+// CHECK-NEXT:           "line": 2
+// CHECK-NEXT:         },
+// CHECK-NEXT:         "start": {
+// CHECK-NEXT:           "character": 1,
+// CHECK-NEXT:           "line": 2
+// CHECK-NEXT:         }
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "text": "* - And a list"
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "range": {
+// CHECK-NEXT:         "end": {
+// CHECK-NEXT:           "character": 1,
+// CHECK-NEXT:           "line": 3
+// CHECK-NEXT:         },
+// CHECK-NEXT:         "start": {
+// CHECK-NEXT:           "character": 1,
+// CHECK-NEXT:           "line": 3
+// CHECK-NEXT:         }
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "text": ""
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "range": {
+// CHECK-NEXT:         "end": {
+// CHECK-NEXT:           "character": 55,
+// CHECK-NEXT:           "line": 4
+// CHECK-NEXT:         },
+// CHECK-NEXT:         "start": {
+// CHECK-NEXT:           "character": 4,
+// CHECK-NEXT:           "line": 4
+// CHECK-NEXT:         }
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "text": "This is an auto-generated wrapper for safer interop"
+// CHECK-NEXT:     }
+// CHECK-NEXT:   ],
+// CHECK-NEXT:   "module": "MyClangModule",
+// CHECK-NEXT:   "uri": "file://@__swiftmacro_So9testCDecl15_SwiftifyImportfMp_.swift"
+// CHECK-NEXT: }
diff --git a/test/SourceKit/CursorInfo/cursor_generated_interface.swift b/test/SourceKit/CursorInfo/cursor_generated_interface.swift
index 9534fd96c3adc..5795412702e4e 100644
--- a/test/SourceKit/CursorInfo/cursor_generated_interface.swift
+++ b/test/SourceKit/CursorInfo/cursor_generated_interface.swift
@@ -41,7 +41,7 @@ public class ASwiftType {
 }
 
 // LibA is a mixed framework with no source info and a submodule
-// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=12:36 -print-raw-response | %FileCheck %s --check-prefix=CHECKA
+// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=11:36 -print-raw-response | %FileCheck %s --check-prefix=CHECKA
 // CHECKA: key.name: "ASwiftType"
 // CHECKA: key.modulename: "LibA"
 // CHECKA: key.decl_lang: source.lang.swift
@@ -60,7 +60,7 @@ framework module LibA {
 @interface AObjcType
 @end
 
-// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=12:54 -print-raw-response | %FileCheck %s --check-prefix=CHECKAOBJ
+// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=11:54 -print-raw-response | %FileCheck %s --check-prefix=CHECKAOBJ
 // CHECKAOBJ: key.name: "AObjcType"
 // CHECKAOBJ: key.line: [[@LINE-5]]
 // CHECKAOBJ: key.column: 12
@@ -72,7 +72,7 @@ framework module LibA {
 @interface ASubType
 @end
 
-// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=12:70 -print-raw-response | %FileCheck %s --check-prefix=CHECKASUB
+// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=11:70 -print-raw-response | %FileCheck %s --check-prefix=CHECKASUB
 // CHECKASUB: key.name: "ASubType"
 // CHECKASUB: key.line: [[@LINE-5]]
 // CHECKASUB: key.column: 12
@@ -84,7 +84,7 @@ framework module LibA {
 public class BType {}
 
 // LibB has source info
-// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=14:32 -print-raw-response | %FileCheck %s --check-prefix=CHECKB
+// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=13:32 -print-raw-response | %FileCheck %s --check-prefix=CHECKB
 // CHECKB: key.name: "BType"
 // CHECKB: key.line: [[@LINE-5]]
 // CHECKB: key.column: 14
@@ -96,7 +96,7 @@ public class BType {}
 public class CType {}
 
 // LibC has no source info
-// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=14:47 -print-raw-response | %FileCheck %s --check-prefix=CHECKC
+// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=13:47 -print-raw-response | %FileCheck %s --check-prefix=CHECKC
 // CHECKC: key.name: "CType"
 // CHECKC: key.modulename: "LibC"
 // CHECKC: key.decl_lang: source.lang.swift
@@ -105,7 +105,7 @@ public class CType {}
 @interface DType
 @end
 
-// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=14:57 -print-raw-response | %FileCheck %s --check-prefix=CHECKD
+// RUN: %sourcekitd-test -req=interface-gen-open -module LibA -- -F %t/frameworks -target %target-triple == -req=cursor -pos=13:57 -print-raw-response | %FileCheck %s --check-prefix=CHECKD
 // CHECKD: key.name: "DType"
 // CHECKD: key.line: [[@LINE-5]]
 // CHECKD: key.column: 12
diff --git a/test/SourceKit/CursorInfo/cursor_generics.swift b/test/SourceKit/CursorInfo/cursor_generics.swift
index 86d9d3340a893..640b173f3d41e 100644
--- a/test/SourceKit/CursorInfo/cursor_generics.swift
+++ b/test/SourceKit/CursorInfo/cursor_generics.swift
@@ -34,6 +34,12 @@ public protocol Proto<Assoc> {
   associatedtype Assoc
 }
 
+struct HasValueGenericParam<let Param: Int> {
+  func foo() {
+    _ = Param
+  }
+}
+
 // RUN: %sourcekitd-test -req=cursor -pos=1:10 %s -- %s | %FileCheck -check-prefix=CHECK1 %s
 // CHECK1: <Declaration>func testGenerics&lt;T&gt;(x: <Type usr="s:15cursor_generics12testGenerics1xyx_tlF1TL_xmfp">T</Type>)</Declaration>
 
@@ -69,3 +75,7 @@ public protocol Proto<Assoc> {
 // CHECK_ASSOC_COMMON-NEXT: source.refactoring.kind.rename.global
 // CHECK_ASSOC_COMMON-NEXT: Global Rename
 // CHECK_ASSOC_COMMON-NEXT: ACTIONS END
+
+// RUN: %sourcekitd-test -req=cursor -pos=39:9 %s -- %s | %FileCheck -check-prefix=CHECK_VALUE_GENERIC %s
+// CHECK_VALUE_GENERIC: source.lang.swift.ref.generic_type_param (37:33-37:38)
+// CHECK_VALUE_GENERIC: <Declaration>let Param : <Type usr="s:Si">Int</Type></Declaration>
diff --git a/test/SourceKit/CursorInfo/cursor_infer_nonmutating_from_property_wrapper.swift b/test/SourceKit/CursorInfo/cursor_infer_nonmutating_from_property_wrapper.swift
index bb8d38f4072d0..46882fdd36f97 100644
--- a/test/SourceKit/CursorInfo/cursor_infer_nonmutating_from_property_wrapper.swift
+++ b/test/SourceKit/CursorInfo/cursor_infer_nonmutating_from_property_wrapper.swift
@@ -14,4 +14,4 @@ func test() {
     }
 }
 
-// CHECK: <Declaration>@<Type usr="s:46cursor_infer_nonmutating_from_property_wrapper5StateV">State</Type> var myState: &lt;&lt;error type&gt;&gt; { get nonmutating set }</Declaration>
+// CHECK: <Declaration>@<Type usr="s:46cursor_infer_nonmutating_from_property_wrapper5StateV">State</Type> var myState: _ { get nonmutating set }</Declaration>
diff --git a/test/SourceKit/CursorInfo/rdar130771574.swift b/test/SourceKit/CursorInfo/rdar130771574.swift
new file mode 100644
index 0000000000000..5e890b6f5d104
--- /dev/null
+++ b/test/SourceKit/CursorInfo/rdar130771574.swift
@@ -0,0 +1,10 @@
+struct S {
+  var x: Int
+}
+
+// Make sure we can still resolve 'x' even with the trailing dot.
+func foo(_ s: S) {
+  s.x.
+  // RUN: %sourcekitd-test -req=cursor -pos=%(line-1):5 %s -- %s -module-name main | %FileCheck %s
+}
+// CHECK: s:4main1SV1xSivp
diff --git a/test/SourceKit/Diagnostics/embedded_non_wmo.swift b/test/SourceKit/Diagnostics/embedded_non_wmo.swift
index 7e8c57ee3d752..5dd9987c71ae4 100644
--- a/test/SourceKit/Diagnostics/embedded_non_wmo.swift
+++ b/test/SourceKit/Diagnostics/embedded_non_wmo.swift
@@ -16,6 +16,11 @@ func foo() {
     bar(Int.self)
 }
 
+func testNonCopyable() {
+  let nc = NonCopyable()
+  nc.doSomething()
+}
+
 @main
 struct Main {
     var someClass = SomeClass()
@@ -31,6 +36,11 @@ final class SomeClass {}
 
 func bar<T>(_ T: T.Type) {}
 
+struct NonCopyable : ~Copyable {
+  func doSomething() {}
+  deinit {}
+}
+
 // CHECK:      {
 // CHECK-NEXT:   key.diagnostics: [
 // CHECK-NEXT:   ]
diff --git a/test/SourceKit/Diagnostics/remarks.swift b/test/SourceKit/Diagnostics/remarks.swift
new file mode 100644
index 0000000000000..f4febb0dd772a
--- /dev/null
+++ b/test/SourceKit/Diagnostics/remarks.swift
@@ -0,0 +1,15 @@
+// RUN: env %sourcekitd-test -req=diags %s -- %s -Xfrontend -Rmodule-api-import | %FileCheck %s
+public typealias Foo = String
+
+// CHECK:      {
+// CHECK-NEXT:   key.diagnostics: [
+// CHECK-NEXT:   {
+// CHECK-NEXT:       key.line: 2,
+// CHECK-NEXT:       key.column: 24,
+// CHECK-NEXT:       key.filepath: "{{.*}}",
+// CHECK-NEXT:       key.severity: source.diagnostic.severity.remark,
+// CHECK-NEXT:       key.id: "module_api_import",
+// CHECK-NEXT:       key.description: "struct 'String' is imported via 'Swift'"
+// CHECK-NEXT:   }
+// CHECK-NEXT:   ]
+// CHECK-NEXT: }
diff --git a/test/SourceKit/DocSupport/doc_clang_module.swift.response b/test/SourceKit/DocSupport/doc_clang_module.swift.response
index 2b018fe0704bd..a50473bbadb07 100644
--- a/test/SourceKit/DocSupport/doc_clang_module.swift.response
+++ b/test/SourceKit/DocSupport/doc_clang_module.swift.response
@@ -81,28 +81,10 @@ struct FooRuncingOptions : OptionSet {
 
     static func != (_ lhs: FooRuncingOptions, _ rhs: FooRuncingOptions) -> Bool
 
-    @inlinable init(arrayLiteral arrayLiteral: FooRuncingOptions...)
-}
-
-extension FooRuncingOptions {
-
-    @inlinable init<S>(_ sequence: S) where S : Sequence, FooRuncingOptions == S.Element
-
-    @inlinable mutating func subtract(_ other: FooRuncingOptions)
-
-    @inlinable func isSubset(of other: FooRuncingOptions) -> Bool
-
-    @inlinable func isSuperset(of other: FooRuncingOptions) -> Bool
-
-    @inlinable func isDisjoint(with other: FooRuncingOptions) -> Bool
-
-    @inlinable func subtracting(_ other: FooRuncingOptions) -> FooRuncingOptions
-
-    @inlinable var isEmpty: Bool { get }
-
-    @inlinable func isStrictSuperset(of other: FooRuncingOptions) -> Bool
+    @discardableResult
+    mutating func insert(_ newMember: FooRuncingOptions) -> (inserted: Bool, memberAfterInsert: FooRuncingOptions)
 
-    @inlinable func isStrictSubset(of other: FooRuncingOptions) -> Bool
+    @inlinable init(arrayLiteral arrayLiteral: FooRuncingOptions...)
 }
 
 extension FooRuncingOptions {
@@ -139,6 +121,27 @@ extension FooRuncingOptions {
     @inlinable mutating func formSymmetricDifference(_ other: FooRuncingOptions)
 }
 
+extension FooRuncingOptions {
+
+    @inlinable init<S>(_ sequence: S) where S : Sequence, FooRuncingOptions == S.Element
+
+    @inlinable mutating func subtract(_ other: FooRuncingOptions)
+
+    @inlinable func isSubset(of other: FooRuncingOptions) -> Bool
+
+    @inlinable func isSuperset(of other: FooRuncingOptions) -> Bool
+
+    @inlinable func isDisjoint(with other: FooRuncingOptions) -> Bool
+
+    @inlinable func subtracting(_ other: FooRuncingOptions) -> FooRuncingOptions
+
+    @inlinable var isEmpty: Bool { get }
+
+    @inlinable func isStrictSuperset(of other: FooRuncingOptions) -> Bool
+
+    @inlinable func isStrictSubset(of other: FooRuncingOptions) -> Bool
+}
+
 struct FooStruct1 {
 
     init()
@@ -1534,3489 +1537,3550 @@ var FooSubUnnamedEnumeratorA1: Int { get }
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
     key.offset: 1717,
-    key.length: 10
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 1728,
-    key.length: 4
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 1733,
-    key.length: 12
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 1746,
-    key.length: 12
-  },
-  {
-    key.kind: source.lang.swift.ref.struct,
-    key.name: "FooRuncingOptions",
-    key.usr: "c:@E@FooRuncingOptions",
-    key.offset: 1760,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 1785,
-    key.length: 9
-  },
-  {
-    key.kind: source.lang.swift.ref.struct,
-    key.name: "FooRuncingOptions",
-    key.usr: "c:@E@FooRuncingOptions",
-    key.offset: 1795,
-    key.length: 17
+    key.length: 18
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 1820,
-    key.length: 10
+    key.offset: 1740,
+    key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 1831,
+    key.offset: 1749,
     key.length: 4
   },
   {
-    key.kind: source.lang.swift.ref.generic_type_param,
-    key.name: "S",
-    key.usr: "s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc1SL_qd__mfp",
-    key.offset: 1836,
-    key.length: 1
+    key.kind: source.lang.swift.syntaxtype.identifier,
+    key.offset: 1754,
+    key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 1839,
+    key.offset: 1761,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 1841,
-    key.length: 8
-  },
-  {
-    key.kind: source.lang.swift.ref.generic_type_param,
-    key.name: "S",
-    key.usr: "s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc1SL_qd__mfp",
-    key.offset: 1851,
-    key.length: 1
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 1854,
-    key.length: 5
-  },
-  {
-    key.kind: source.lang.swift.ref.generic_type_param,
-    key.name: "S",
-    key.usr: "s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc1SL_qd__mfp",
-    key.offset: 1860,
-    key.length: 1
-  },
-  {
-    key.kind: source.lang.swift.ref.protocol,
-    key.name: "Sequence",
-    key.usr: "s:ST",
-    key.offset: 1864,
-    key.length: 8
+    key.offset: 1763,
+    key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "FooRuncingOptions",
     key.usr: "c:@E@FooRuncingOptions",
-    key.offset: 1874,
+    key.offset: 1774,
     key.length: 17
   },
   {
-    key.kind: source.lang.swift.syntaxtype.operator,
-    key.offset: 1892,
-    key.length: 2
-  },
-  {
-    key.kind: source.lang.swift.ref.generic_type_param,
-    key.name: "S",
-    key.usr: "s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc1SL_qd__mfp",
-    key.offset: 1895,
-    key.length: 1
-  },
-  {
-    key.kind: source.lang.swift.ref.associatedtype,
-    key.name: "Element",
-    key.usr: "s:ST7ElementQa",
-    key.offset: 1897,
-    key.length: 7
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 1910,
-    key.length: 10
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 1921,
+    key.kind: source.lang.swift.syntaxtype.identifier,
+    key.offset: 1797,
     key.length: 8
   },
   {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 1930,
+    key.kind: source.lang.swift.ref.struct,
+    key.name: "Bool",
+    key.usr: "s:Sb",
+    key.offset: 1807,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 1935,
-    key.length: 8
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 1944,
-    key.length: 1
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 1946,
-    key.length: 5
+    key.offset: 1813,
+    key.length: 17
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "FooRuncingOptions",
     key.usr: "c:@E@FooRuncingOptions",
-    key.offset: 1953,
+    key.offset: 1832,
     key.length: 17
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 1977,
+    key.offset: 1856,
     key.length: 10
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 1988,
+    key.offset: 1867,
     key.length: 4
   },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 1993,
-    key.length: 8
-  },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 2002,
-    key.length: 2
+    key.offset: 1872,
+    key.length: 12
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 2005,
-    key.length: 5
+    key.offset: 1885,
+    key.length: 12
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "FooRuncingOptions",
     key.usr: "c:@E@FooRuncingOptions",
-    key.offset: 2012,
+    key.offset: 1899,
     key.length: 17
   },
+  {
+    key.kind: source.lang.swift.syntaxtype.keyword,
+    key.offset: 1924,
+    key.length: 9
+  },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.name: "Bool",
-    key.usr: "s:Sb",
-    key.offset: 2034,
-    key.length: 4
+    key.name: "FooRuncingOptions",
+    key.usr: "c:@E@FooRuncingOptions",
+    key.offset: 1934,
+    key.length: 17
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 2044,
+    key.offset: 1959,
     key.length: 10
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 2055,
+    key.offset: 1970,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 2060,
-    key.length: 10
+    key.offset: 1975,
+    key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 2071,
-    key.length: 2
+    key.offset: 1981,
+    key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 2074,
+    key.offset: 1983,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "FooRuncingOptions",
     key.usr: "c:@E@FooRuncingOptions",
-    key.offset: 2081,
+    key.offset: 1990,
     key.length: 17
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.name: "Bool",
-    key.usr: "s:Sb",
-    key.offset: 2103,
-    key.length: 4
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@@ -5530,7 +5594,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.usr: "c:@E@FooRuncingOptions",
     key.doc.full_as_xml: "<Enum line=\"1\" column=\"1\"><Name>FooRuncingOptions</Name><USR>c:@E@FooRuncingOptions</USR><Declaration>struct FooRuncingOptions : OptionSet</Declaration><Abstract><Para> Aaa.  FooRuncingOptions.  Bbb.</Para></Abstract></Enum>",
     key.offset: 1447,
-    key.length: 336,
+    key.length: 475,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>FooRuncingOptions</decl.name> : <ref.protocol usr=\"s:s9OptionSetP\">OptionSet</ref.protocol></decl.struct>",
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       {
@@ -5579,231 +5643,60 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::c:@E@FooRuncingOptions",
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-        key.fully_annotated_decl: "<decl.var.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>isEmpty</decl.name>: <decl.var.type><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
-      },
       {
         key.kind: source.lang.swift.decl.function.method.instance,
-        key.name: "isStrictSuperset(of:)",
-        key.usr: "s:s10SetAlgebraPsE16isStrictSuperset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions",
-        key.original_usr: "s:s10SetAlgebraPsE16isStrictSuperset2ofSbx_tF",
-        key.doc.full_as_xml: "<Function><Name>isStrictSuperset(of:)</Name><USR>s:s10SetAlgebraPsE16isStrictSuperset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func isStrictSuperset(of other: FooRuncingOptions) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value that indicates whether this set is a strict superset of the given set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A set of the same type as the current set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para><codeVoice>true</codeVoice> if the set is a strict superset of <codeVoice>other</codeVoice>; otherwise, <codeVoice>false</codeVoice>.</Para></ResultDiscussion><Discussion><Para>Set <emphasis>A</emphasis> is a strict superset of another set <emphasis>B</emphasis> if every member of <emphasis>B</emphasis> is also a member of <emphasis>A</emphasis> and <emphasis>A</emphasis> contains at least one element that is <emphasis>not</emphasis> a member of <emphasis>B</emphasis>.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let employees: Set = [\"Alicia\", \"Bethany\", \"Chris\", \"Diana\", \"Eric\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let attendees: Set = [\"Alicia\", \"Bethany\", \"Diana\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(employees.isStrictSuperset(of: attendees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// A set is never a strict superset of itself:]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(employees.isStrictSuperset(of: employees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"false\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
-        key.offset: 2308,
-        key.length: 69,
-        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>isStrictSuperset</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>of</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.method.instance>",
+        key.name: "insert(_:)",
+        key.usr: "s:s9OptionSetPs7ElementQzRszs17FixedWidthInteger8RawValueRpzrlE6insertySb8inserted_x17memberAfterInserttxF::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s9OptionSetPs7ElementQzRszs17FixedWidthInteger8RawValueRpzrlE6insertySb8inserted_x17memberAfterInserttxF",
+        key.offset: 1717,
+        key.length: 133,
+        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@discardableResult</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.attribute.builtin><syntaxtype.attribute.name>@_alwaysEmitIntoClient</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>mutating</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>insert</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>newMember</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><tuple>(<tuple.element><tuple.element.argument_label>inserted</tuple.element.argument_label>: <tuple.element.type><ref.struct usr=\"s:Sb\">Bool</ref.struct></tuple.element.type></tuple.element>, <tuple.element><tuple.element.argument_label>memberAfterInsert</tuple.element.argument_label>: <tuple.element.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></tuple.element.type></tuple.element>)</tuple></decl.function.returntype></decl.function.method.instance>",
         key.entities: [
           {
             key.kind: source.lang.swift.decl.var.local,
-            key.keyword: "of",
-            key.name: "other",
-            key.offset: 2351,
+            key.keyword: "_",
+            key.name: "newMember",
+            key.offset: 1774,
             key.length: 17
           }
         ]
       },
       {
-        key.kind: source.lang.swift.decl.function.method.instance,
-        key.name: "isStrictSubset(of:)",
-        key.usr: "s:s10SetAlgebraPsE14isStrictSubset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions",
-        key.original_usr: "s:s10SetAlgebraPsE14isStrictSubset2ofSbx_tF",
-        key.doc.full_as_xml: "<Function><Name>isStrictSubset(of:)</Name><USR>s:s10SetAlgebraPsE14isStrictSubset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func isStrictSubset(of other: FooRuncingOptions) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value that indicates whether this set is a strict subset of the given set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A set of the same type as the current set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para><codeVoice>true</codeVoice> if the set is a strict subset of <codeVoice>other</codeVoice>; otherwise, <codeVoice>false</codeVoice>.</Para></ResultDiscussion><Discussion><Para>Set <emphasis>A</emphasis> is a strict subset of another set <emphasis>B</emphasis> if every member of <emphasis>A</emphasis> is also a member of <emphasis>B</emphasis> and <emphasis>B</emphasis> contains at least one element that is not a member of <emphasis>A</emphasis>.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let employees: Set = [\"Alicia\", \"Bethany\", \"Chris\", \"Diana\", \"Eric\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let attendees: Set = [\"Alicia\", \"Bethany\", \"Diana\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(attendees.isStrictSubset(of: employees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// A set is never a strict subset of itself:]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(attendees.isStrictSubset(of: attendees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"false\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
-        key.offset: 2383,
-        key.length: 67,
-        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>isStrictSubset</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>of</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.method.instance>",
+        key.kind: source.lang.swift.decl.function.constructor,
+        key.name: "init(arrayLiteral:)",
+        key.usr: "s:s10SetAlgebraPs7ElementQz012ArrayLiteralC0RtzrlE05arrayE0xAFd_tcfc::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPs7ElementQz012ArrayLiteralC0RtzrlE05arrayE0xAFd_tcfc",
+        key.doc.full_as_xml: "<Function><Name>init(arrayLiteral:)</Name><USR>s:s10SetAlgebraPs7ElementQz012ArrayLiteralC0RtzrlE05arrayE0xAFd_tcfc::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable init(arrayLiteral: FooRuncingOptions...)</Declaration><CommentParts><Abstract><Para>Creates a set containing the elements of the given array literal.</Para></Abstract><Parameters><Parameter><Name>arrayLiteral</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A list of elements of the new set.</Para></Discussion></Parameter></Parameters><Discussion><Para>Do not call this initializer directly. It is used by the compiler when you use an array literal. Instead, create a new set using an array literal as its value by enclosing a comma-separated list of values in square brackets. You can use an array literal anywhere a set is expected by the type context.</Para><Para>Here, a set of strings is created from an array literal holding only strings:</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let ingredients: Set = [\"cocoa beans\", \"sugar\", \"cocoa butter\", \"salt\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[if ingredients.isSuperset(of: [\"sugar\", \"salt\"]) {]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[    print(\"Whatever it is, it's bound to be delicious!\")]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[}]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"Whatever it is, it's bound to be delicious!\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
+        key.offset: 1856,
+        key.length: 64,
+        key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>arrayLiteral</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct>...</decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
           {
             key.kind: source.lang.swift.decl.var.local,
-            key.keyword: "of",
-            key.name: "other",
-            key.offset: 2424,
-            key.length: 17
+            key.keyword: "arrayLiteral",
+            key.name: "arrayLiteral",
+            key.offset: 1899,
+            key.length: 20
           }
         ]
       }
@@ -5812,7 +5705,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
   {
     key.kind: source.lang.swift.decl.extension.struct,
     key.doc.full_as_xml: "<Other><Name></Name><Declaration>extension FooRuncingOptions</Declaration><CommentParts><Abstract><Para><codeVoice>OptionSet</codeVoice> requirements for which default implementations are supplied.</Para></Abstract><Discussion><Note><Para>A type conforming to <codeVoice>OptionSet</codeVoice> can implement any of these initializers or methods, and those implementations will be used in lieu of these defaults.</Para></Note></Discussion></CommentParts></Other>",
-    key.offset: 2454,
+    key.offset: 1924,
     key.length: 280,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct>",
     key.extends: {
@@ -5827,7 +5720,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPsE5unionyxxF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPsE5unionyxxF",
         key.doc.full_as_xml: "<Function><Name>union(_:)</Name><USR>s:s9OptionSetPsE5unionyxxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func union(_ other: FooRuncingOptions) -&gt; FooRuncingOptions</Declaration><CommentParts><Abstract><Para>Returns a new option set of the elements contained in this set, in the given set, or in both.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>An option set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para>A new option set made up of the elements contained in this set, in <codeVoice>other</codeVoice>, or in both.</Para></ResultDiscussion><Discussion><Para>This example uses the <codeVoice>union(_:)</codeVoice> method to add two more shipping options to the default set.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let defaultShipping = ShippingOptions.standard]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let memberShipping = defaultShipping.union([.secondDay, .priority])]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(memberShipping.contains(.priority))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
-        key.offset: 2489,
+        key.offset: 1959,
         key.length: 70,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>union</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.function.returntype></decl.function.method.instance>",
         key.entities: [
@@ -5835,7 +5728,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "other",
-            key.offset: 2520,
+            key.offset: 1990,
             key.length: 17
           }
         ]
@@ -5846,7 +5739,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPsE12intersectionyxxF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPsE12intersectionyxxF",
         key.doc.full_as_xml: "<Function><Name>intersection(_:)</Name><USR>s:s9OptionSetPsE12intersectionyxxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func intersection(_ other: FooRuncingOptions) -&gt; FooRuncingOptions</Declaration><CommentParts><Abstract><Para>Returns a new option set with only the elements contained in both this set and the given set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>An option set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para>A new option set with only the elements contained in both this set and <codeVoice>other</codeVoice>.</Para></ResultDiscussion><Discussion><Para>This example uses the <codeVoice>intersection(_:)</codeVoice> method to limit the available shipping options to what can be used with a PO Box destination.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[// Can only ship standard or priority to PO Boxes]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let poboxShipping: ShippingOptions = [.standard, .priority]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let memberShipping: ShippingOptions =]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[        [.standard, .priority, .secondDay]]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let availableOptions = memberShipping.intersection(poboxShipping)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(availableOptions.contains(.priority))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(availableOptions.contains(.secondDay))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"false\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
-        key.offset: 2565,
+        key.offset: 2035,
         key.length: 77,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>intersection</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.function.returntype></decl.function.method.instance>",
         key.entities: [
@@ -5854,7 +5747,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "other",
-            key.offset: 2603,
+            key.offset: 2073,
             key.length: 17
           }
         ]
@@ -5865,7 +5758,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPsE19symmetricDifferenceyxxF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPsE19symmetricDifferenceyxxF",
         key.doc.full_as_xml: "<Function><Name>symmetricDifference(_:)</Name><USR>s:s9OptionSetPsE19symmetricDifferenceyxxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func symmetricDifference(_ other: FooRuncingOptions) -&gt; FooRuncingOptions</Declaration><CommentParts><Abstract><Para>Returns a new option set with the elements contained in this set or in the given set, but not in both.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>An option set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para>A new option set with only the elements contained in either this set or <codeVoice>other</codeVoice>, but not in both.</Para></ResultDiscussion></CommentParts></Function>",
-        key.offset: 2648,
+        key.offset: 2118,
         key.length: 84,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>symmetricDifference</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.function.returntype></decl.function.method.instance>",
         key.entities: [
@@ -5873,7 +5766,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "other",
-            key.offset: 2693,
+            key.offset: 2163,
             key.length: 17
           }
         ]
@@ -5883,7 +5776,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
   {
     key.kind: source.lang.swift.decl.extension.struct,
     key.doc.full_as_xml: "<Other><Name></Name><Declaration>extension FooRuncingOptions</Declaration><CommentParts><Abstract><Para><codeVoice>OptionSet</codeVoice> requirements for which default implementations are supplied when <codeVoice>Element == Self</codeVoice>, which is the default.</Para></Abstract><Discussion><Note><Para>A type conforming to <codeVoice>OptionSet</codeVoice> can implement any of these initializers or methods, and those implementations will be used in lieu of these defaults.</Para></Note></Discussion></CommentParts></Other>",
-    key.offset: 2736,
+    key.offset: 2206,
     key.length: 476,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct>",
     key.extends: {
@@ -5898,7 +5791,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPs7ElementQzRszrlE8containsySbxF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPs7ElementQzRszrlE8containsySbxF",
         key.doc.full_as_xml: "<Function><Name>contains(_:)</Name><USR>s:s9OptionSetPs7ElementQzRszrlE8containsySbxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func contains(_ member: FooRuncingOptions) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value that indicates whether a given element is a member of the option set.</Para></Abstract><Parameters><Parameter><Name>member</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>The element to look for in the option set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para><codeVoice>true</codeVoice> if the option set contains <codeVoice>member</codeVoice>; otherwise, <codeVoice>false</codeVoice>.</Para></ResultDiscussion><Discussion><Para>This example uses the <codeVoice>contains(_:)</codeVoice> method to check whether next-day shipping is in the <codeVoice>availableOptions</codeVoice> instance.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let availableOptions = ShippingOptions.express]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[if availableOptions.contains(.nextDay) {]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[    print(\"Next day shipping available\")]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[}]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"Next day shipping available\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
-        key.offset: 2771,
+        key.offset: 2241,
         key.length: 61,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>contains</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>member</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.method.instance>",
         key.entities: [
@@ -5906,7 +5799,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "member",
-            key.offset: 2806,
+            key.offset: 2276,
             key.length: 17
           }
         ]
@@ -5917,7 +5810,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPs7ElementQzRszrlE6insertySb8inserted_x17memberAfterInserttxF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPs7ElementQzRszrlE6insertySb8inserted_x17memberAfterInserttxF",
         key.doc.full_as_xml: "<Function><Name>insert(_:)</Name><USR>s:s9OptionSetPs7ElementQzRszrlE6insertySb8inserted_x17memberAfterInserttxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@discardableResult\n@inlinable mutating func insert(_ newMember: FooRuncingOptions) -&gt; (inserted: Bool, memberAfterInsert: FooRuncingOptions)</Declaration><CommentParts><Abstract><Para>Adds the given element to the option set if it is not already a member.</Para></Abstract><Parameters><Parameter><Name>newMember</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>The element to insert.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para><codeVoice>(true, newMember)</codeVoice> if <codeVoice>newMember</codeVoice> was not contained in <codeVoice>self</codeVoice>. Otherwise, returns <codeVoice>(false, oldMember)</codeVoice>, where <codeVoice>oldMember</codeVoice> is the member of the set equal to <codeVoice>newMember</codeVoice>.</Para></ResultDiscussion><Discussion><Para>In the following example, the <codeVoice>.secondDay</codeVoice> shipping option is added to the <codeVoice>freeOptions</codeVoice> option set if <codeVoice>purchasePrice</codeVoice> is greater than 50.0. For the <codeVoice>ShippingOptions</codeVoice> declaration, see the <codeVoice>OptionSet</codeVoice> protocol discussion.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let purchasePrice = 87.55]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered><zCodeLineNumbered><![CDATA[var freeOptions: ShippingOptions = [.standard, .priority]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[if purchasePrice > 50 {]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[    freeOptions.insert(.secondDay)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[}]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(freeOptions.contains(.secondDay))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
-        key.offset: 2838,
+        key.offset: 2308,
         key.length: 144,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@discardableResult</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>mutating</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>insert</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>newMember</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><tuple>(<tuple.element><tuple.element.argument_label>inserted</tuple.element.argument_label>: <tuple.element.type><ref.struct usr=\"s:Sb\">Bool</ref.struct></tuple.element.type></tuple.element>, <tuple.element><tuple.element.argument_label>memberAfterInsert</tuple.element.argument_label>: <tuple.element.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></tuple.element.type></tuple.element>)</tuple></decl.function.returntype></decl.function.method.instance>",
         key.entities: [
@@ -5925,7 +5818,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "newMember",
-            key.offset: 2906,
+            key.offset: 2376,
             key.length: 17
           }
         ]
@@ -5936,7 +5829,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPs7ElementQzRszrlE6removeyxSgxF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPs7ElementQzRszrlE6removeyxSgxF",
         key.doc.full_as_xml: "<Function><Name>remove(_:)</Name><USR>s:s9OptionSetPs7ElementQzRszrlE6removeyxSgxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@discardableResult\n@inlinable mutating func remove(_ member: FooRuncingOptions) -&gt; FooRuncingOptions?</Declaration><CommentParts><Abstract><Para>Removes the given element and all elements subsumed by it.</Para></Abstract><Parameters><Parameter><Name>member</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>The element of the set to remove.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para>The intersection of <codeVoice>[member]</codeVoice> and the set, if the intersection was nonempty; otherwise, <codeVoice>nil</codeVoice>.</Para></ResultDiscussion><Discussion><Para>In the following example, the <codeVoice>.priority</codeVoice> shipping option is removed from the <codeVoice>options</codeVoice> option set. Attempting to remove the same shipping option a second time results in <codeVoice>nil</codeVoice>, because <codeVoice>options</codeVoice> no longer contains <codeVoice>.priority</codeVoice> as a member.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[var options: ShippingOptions = [.secondDay, .priority]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let priorityOption = options.remove(.priority)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(priorityOption == .priority)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(options.remove(.priority))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"nil\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing><Para>In the next example, the <codeVoice>.express</codeVoice> element is passed to <codeVoice>remove(_:)</codeVoice>. Although <codeVoice>.express</codeVoice> is not a member of <codeVoice>options</codeVoice>, <codeVoice>.express</codeVoice> subsumes the remaining <codeVoice>.secondDay</codeVoice> element of the option set. Therefore, <codeVoice>options</codeVoice> is emptied and the intersection between <codeVoice>.express</codeVoice> and <codeVoice>options</codeVoice> is returned.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let expressOption = options.remove(.express)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(expressOption == .express)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"false\"]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(expressOption == .secondDay)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
-        key.offset: 2988,
+        key.offset: 2458,
         key.length: 105,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@discardableResult</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>mutating</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>remove</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>member</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct>?</decl.function.returntype></decl.function.method.instance>",
         key.entities: [
@@ -5944,7 +5837,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "member",
-            key.offset: 3053,
+            key.offset: 2523,
             key.length: 17
           }
         ]
@@ -5955,7 +5848,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPs7ElementQzRszrlE6update4withxSgx_tF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPs7ElementQzRszrlE6update4withxSgx_tF",
         key.doc.full_as_xml: "<Function><Name>update(with:)</Name><USR>s:s9OptionSetPs7ElementQzRszrlE6update4withxSgx_tF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@discardableResult\n@inlinable mutating func update(with newMember: FooRuncingOptions) -&gt; FooRuncingOptions?</Declaration><CommentParts><Abstract><Para>Inserts the given element into the set.</Para></Abstract><ResultDiscussion><Para>The intersection of <codeVoice>[newMember]</codeVoice> and the set if the intersection was nonempty; otherwise, <codeVoice>nil</codeVoice>.</Para></ResultDiscussion><Discussion><Para>If <codeVoice>newMember</codeVoice> is not contained in the set but subsumes current members of the set, the subsumed members are returned.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[var options: ShippingOptions = [.secondDay, .priority]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let replaced = options.update(with: .express)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(replaced == .secondDay)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
-        key.offset: 3099,
+        key.offset: 2569,
         key.length: 111,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@discardableResult</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>mutating</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>update</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>with</decl.var.parameter.argument_label> <decl.var.parameter.name>newMember</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct>?</decl.function.returntype></decl.function.method.instance>",
         key.entities: [
@@ -5963,7 +5856,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "with",
             key.name: "newMember",
-            key.offset: 3170,
+            key.offset: 2640,
             key.length: 17
           }
         ]
@@ -5973,7 +5866,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
   {
     key.kind: source.lang.swift.decl.extension.struct,
     key.doc.full_as_xml: "<Other><Name></Name><Declaration>extension FooRuncingOptions</Declaration><CommentParts><Abstract><Para><codeVoice>OptionSet</codeVoice> requirements for which default implementations are supplied when <codeVoice>RawValue</codeVoice> conforms to <codeVoice>FixedWidthInteger</codeVoice>, which is the usual case.  Each distinct bit of an option set’s <codeVoice>.rawValue</codeVoice> corresponds to a disjoint value of the <codeVoice>OptionSet</codeVoice>.</Para></Abstract><Discussion><Note><Para>A type conforming to <codeVoice>OptionSet</codeVoice> can implement any of these initializers or methods, and those implementations will be used in lieu of these defaults.</Para></Note><List-Bullet><Item><Para><codeVoice>union</codeVoice> is implemented as a bitwise “or” (<codeVoice>|</codeVoice>) of <codeVoice>rawValue</codeVoice>s</Para></Item><Item><Para><codeVoice>intersection</codeVoice> is implemented as a bitwise “and” (<codeVoice>&amp;</codeVoice>) of <codeVoice>rawValue</codeVoice>s</Para></Item><Item><Para><codeVoice>symmetricDifference</codeVoice> is implemented as a bitwise “exclusive or” (<codeVoice>^</codeVoice>) of <codeVoice>rawValue</codeVoice>s</Para></Item></List-Bullet></Discussion></CommentParts></Other>",
-    key.offset: 3214,
+    key.offset: 2684,
     key.length: 279,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct>",
     key.extends: {
@@ -5988,7 +5881,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlExycfc::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlExycfc",
         key.doc.full_as_xml: "<Function><Name>init()</Name><USR>s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlExycfc::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable init()</Declaration><CommentParts><Abstract><Para>Creates an empty option set.</Para></Abstract><Discussion><Para>This initializer creates an option set with a raw value of zero.</Para></Discussion></CommentParts></Function>",
-        key.offset: 3249,
+        key.offset: 2719,
         key.length: 17,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>init</syntaxtype.keyword>()</decl.function.constructor>"
       },
@@ -5998,7 +5891,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlE9formUnionyyxF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlE9formUnionyyxF",
         key.doc.full_as_xml: "<Function><Name>formUnion(_:)</Name><USR>s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlE9formUnionyyxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable mutating func formUnion(_ other: FooRuncingOptions)</Declaration><CommentParts><Abstract><Para>Inserts the elements of another set into this option set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>An option set.</Para></Discussion></Parameter></Parameters><Discussion><Para>This method is implemented as a <codeVoice>|</codeVoice> (bitwise OR) operation on the two sets’ raw values.</Para></Discussion></CommentParts></Function>",
-        key.offset: 3272,
+        key.offset: 2742,
         key.length: 62,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>mutating</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>formUnion</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -6006,7 +5899,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "other",
-            key.offset: 3316,
+            key.offset: 2786,
             key.length: 17
           }
         ]
@@ -6017,7 +5910,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlE16formIntersectionyyxF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlE16formIntersectionyyxF",
         key.doc.full_as_xml: "<Function><Name>formIntersection(_:)</Name><USR>s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlE16formIntersectionyyxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable mutating func formIntersection(_ other: FooRuncingOptions)</Declaration><CommentParts><Abstract><Para>Removes all elements of this option set that are not also present in the given set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>An option set.</Para></Discussion></Parameter></Parameters><Discussion><Para>This method is implemented as a <codeVoice>&amp;</codeVoice> (bitwise AND) operation on the two sets’ raw values.</Para></Discussion></CommentParts></Function>",
-        key.offset: 3340,
+        key.offset: 2810,
         key.length: 69,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>mutating</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>formIntersection</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -6025,7 +5918,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "other",
-            key.offset: 3391,
+            key.offset: 2861,
             key.length: 17
           }
         ]
@@ -6036,7 +5929,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlE23formSymmetricDifferenceyyxF::SYNTHESIZED::c:@E@FooRuncingOptions",
         key.original_usr: "s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlE23formSymmetricDifferenceyyxF",
         key.doc.full_as_xml: "<Function><Name>formSymmetricDifference(_:)</Name><USR>s:s9OptionSetPss17FixedWidthInteger8RawValueRpzrlE23formSymmetricDifferenceyyxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable mutating func formSymmetricDifference(_ other: FooRuncingOptions)</Declaration><CommentParts><Abstract><Para>Replaces this set with a new set containing all elements contained in either this set or the given set, but not in both.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>An option set.</Para></Discussion></Parameter></Parameters><Discussion><Para>This method is implemented as a <codeVoice>^</codeVoice> (bitwise XOR) operation on the two sets’ raw values.</Para></Discussion></CommentParts></Function>",
-        key.offset: 3415,
+        key.offset: 2885,
         key.length: 76,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>mutating</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>formSymmetricDifference</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -6044,7 +5937,196 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "other",
-            key.offset: 3473,
+            key.offset: 2943,
+            key.length: 17
+          }
+        ]
+      }
+    ]
+  },
+  {
+    key.kind: source.lang.swift.decl.extension.struct,
+    key.doc.full_as_xml: "<Other><Name></Name><Declaration>extension FooRuncingOptions</Declaration><CommentParts><Abstract><Para><codeVoice>SetAlgebra</codeVoice> requirements for which default implementations are supplied.</Para></Abstract><Discussion><Note><Para>A type conforming to <codeVoice>SetAlgebra</codeVoice> can implement any of these initializers or methods, and those implementations will be used in lieu of these defaults.</Para></Note></Discussion></CommentParts></Other>",
+    key.offset: 2965,
+    key.length: 667,
+    key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct>",
+    key.extends: {
+      key.kind: source.lang.swift.ref.struct,
+      key.name: "FooRuncingOptions",
+      key.usr: "c:@E@FooRuncingOptions"
+    },
+    key.entities: [
+      {
+        key.kind: source.lang.swift.decl.function.constructor,
+        key.name: "init(_:)",
+        key.usr: "s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc",
+        key.generic_params: [
+          {
+            key.name: "S"
+          }
+        ],
+        key.generic_requirements: [
+          {
+            key.description: "S : Sequence"
+          },
+          {
+            key.description: "FooRuncingOptions == S.Element"
+          }
+        ],
+        key.doc.full_as_xml: "<Function><Name>init(_:)</Name><USR>s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable init&lt;S&gt;(_ sequence: S) where S : Sequence, FooRuncingOptions == S.Element</Declaration><CommentParts><Abstract><Para>Creates a new set from a finite sequence of items.</Para></Abstract><Parameters><Parameter><Name>sequence</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>The elements to use as members of the new set.</Para></Discussion></Parameter></Parameters><Discussion><Para>Use this initializer to create a new set from an existing sequence, like an array or a range:</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let validIndices = Set(0..<7).subtracting([2, 4, 5])]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(validIndices)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"[6, 0, 1, 3]\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
+        key.offset: 3000,
+        key.length: 84,
+        key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>init</syntaxtype.keyword>&lt;<ref.generic_type_param usr=\"s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc1SL_qd__mfp\">S</ref.generic_type_param>&gt;(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>sequence</decl.var.parameter.name>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc1SL_qd__mfp\">S</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>) <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc1SL_qd__mfp\">S</ref.generic_type_param> : <ref.protocol usr=\"s:ST\">Sequence</ref.protocol></decl.generic_type_requirement>, <decl.generic_type_requirement><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct> == <ref.generic_type_param usr=\"s:s10SetAlgebraPsEyxqd__ncSTRd__7ElementQyd__ACRtzlufc1SL_qd__mfp\">S</ref.generic_type_param>.<ref.associatedtype usr=\"s:ST7ElementQa\">Element</ref.associatedtype></decl.generic_type_requirement></decl.function.constructor>",
+        key.entities: [
+          {
+            key.kind: source.lang.swift.decl.var.local,
+            key.keyword: "_",
+            key.name: "sequence",
+            key.offset: 3031,
+            key.length: 1
+          }
+        ]
+      },
+      {
+        key.kind: source.lang.swift.decl.function.method.instance,
+        key.name: "subtract(_:)",
+        key.usr: "s:s10SetAlgebraPsE8subtractyyxF::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPsE8subtractyyxF",
+        key.doc.full_as_xml: "<Function><Name>subtract(_:)</Name><USR>s:s10SetAlgebraPsE8subtractyyxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable mutating func subtract(_ other: FooRuncingOptions)</Declaration><CommentParts><Abstract><Para>Removes the elements of the given set from this set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A set of the same type as the current set.</Para></Discussion></Parameter></Parameters><Discussion><Para>In the following example, the elements of the <codeVoice>employees</codeVoice> set that are also members of the <codeVoice>neighbors</codeVoice> set are removed. In particular, the names <codeVoice>&quot;Bethany&quot;</codeVoice> and <codeVoice>&quot;Eric&quot;</codeVoice> are removed from <codeVoice>employees</codeVoice>.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[var employees: Set = [\"Alicia\", \"Bethany\", \"Chris\", \"Diana\", \"Eric\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let neighbors: Set = [\"Bethany\", \"Eric\", \"Forlani\", \"Greta\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[employees.subtract(neighbors)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(employees)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"[\"Diana\", \"Chris\", \"Alicia\"]\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
+        key.offset: 3090,
+        key.length: 61,
+        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>mutating</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>subtract</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
+        key.entities: [
+          {
+            key.kind: source.lang.swift.decl.var.local,
+            key.keyword: "_",
+            key.name: "other",
+            key.offset: 3133,
+            key.length: 17
+          }
+        ]
+      },
+      {
+        key.kind: source.lang.swift.decl.function.method.instance,
+        key.name: "isSubset(of:)",
+        key.usr: "s:s10SetAlgebraPsE8isSubset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPsE8isSubset2ofSbx_tF",
+        key.doc.full_as_xml: "<Function><Name>isSubset(of:)</Name><USR>s:s10SetAlgebraPsE8isSubset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func isSubset(of other: FooRuncingOptions) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value that indicates whether the set is a subset of another set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A set of the same type as the current set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para><codeVoice>true</codeVoice> if the set is a subset of <codeVoice>other</codeVoice>; otherwise, <codeVoice>false</codeVoice>.</Para></ResultDiscussion><Discussion><Para>Set <emphasis>A</emphasis> is a subset of another set <emphasis>B</emphasis> if every member of <emphasis>A</emphasis> is also a member of <emphasis>B</emphasis>.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let employees: Set = [\"Alicia\", \"Bethany\", \"Chris\", \"Diana\", \"Eric\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let attendees: Set = [\"Alicia\", \"Bethany\", \"Diana\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(attendees.isSubset(of: employees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
+        key.offset: 3157,
+        key.length: 61,
+        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>isSubset</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>of</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.method.instance>",
+        key.entities: [
+          {
+            key.kind: source.lang.swift.decl.var.local,
+            key.keyword: "of",
+            key.name: "other",
+            key.offset: 3192,
+            key.length: 17
+          }
+        ]
+      },
+      {
+        key.kind: source.lang.swift.decl.function.method.instance,
+        key.name: "isSuperset(of:)",
+        key.usr: "s:s10SetAlgebraPsE10isSuperset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPsE10isSuperset2ofSbx_tF",
+        key.doc.full_as_xml: "<Function><Name>isSuperset(of:)</Name><USR>s:s10SetAlgebraPsE10isSuperset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func isSuperset(of other: FooRuncingOptions) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value that indicates whether the set is a superset of the given set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A set of the same type as the current set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para><codeVoice>true</codeVoice> if the set is a superset of <codeVoice>other</codeVoice>; otherwise, <codeVoice>false</codeVoice>.</Para></ResultDiscussion><Discussion><Para>Set <emphasis>A</emphasis> is a superset of another set <emphasis>B</emphasis> if every member of <emphasis>B</emphasis> is also a member of <emphasis>A</emphasis>.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let employees: Set = [\"Alicia\", \"Bethany\", \"Chris\", \"Diana\", \"Eric\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let attendees: Set = [\"Alicia\", \"Bethany\", \"Diana\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(employees.isSuperset(of: attendees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
+        key.offset: 3224,
+        key.length: 63,
+        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>isSuperset</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>of</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.method.instance>",
+        key.entities: [
+          {
+            key.kind: source.lang.swift.decl.var.local,
+            key.keyword: "of",
+            key.name: "other",
+            key.offset: 3261,
+            key.length: 17
+          }
+        ]
+      },
+      {
+        key.kind: source.lang.swift.decl.function.method.instance,
+        key.name: "isDisjoint(with:)",
+        key.usr: "s:s10SetAlgebraPsE10isDisjoint4withSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPsE10isDisjoint4withSbx_tF",
+        key.doc.full_as_xml: "<Function><Name>isDisjoint(with:)</Name><USR>s:s10SetAlgebraPsE10isDisjoint4withSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func isDisjoint(with other: FooRuncingOptions) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value that indicates whether the set has no members in common with the given set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A set of the same type as the current set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para><codeVoice>true</codeVoice> if the set has no elements in common with <codeVoice>other</codeVoice>; otherwise, <codeVoice>false</codeVoice>.</Para></ResultDiscussion><Discussion><Para>In the following example, the <codeVoice>employees</codeVoice> set is disjoint with the <codeVoice>visitors</codeVoice> set because no name appears in both sets.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let employees: Set = [\"Alicia\", \"Bethany\", \"Chris\", \"Diana\", \"Eric\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let visitors: Set = [\"Marcia\", \"Nathaniel\", \"Olivia\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(employees.isDisjoint(with: visitors))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
+        key.offset: 3293,
+        key.length: 65,
+        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>isDisjoint</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>with</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.method.instance>",
+        key.entities: [
+          {
+            key.kind: source.lang.swift.decl.var.local,
+            key.keyword: "with",
+            key.name: "other",
+            key.offset: 3332,
+            key.length: 17
+          }
+        ]
+      },
+      {
+        key.kind: source.lang.swift.decl.function.method.instance,
+        key.name: "subtracting(_:)",
+        key.usr: "s:s10SetAlgebraPsE11subtractingyxxF::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPsE11subtractingyxxF",
+        key.doc.full_as_xml: "<Function><Name>subtracting(_:)</Name><USR>s:s10SetAlgebraPsE11subtractingyxxF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func subtracting(_ other: FooRuncingOptions) -&gt; FooRuncingOptions</Declaration><CommentParts><Abstract><Para>Returns a new set containing the elements of this set that do not occur in the given set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A set of the same type as the current set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para>A new set.</Para></ResultDiscussion><Discussion><Para>In the following example, the <codeVoice>nonNeighbors</codeVoice> set is made up of the elements of the <codeVoice>employees</codeVoice> set that are not elements of <codeVoice>neighbors</codeVoice>:</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let employees: Set = [\"Alicia\", \"Bethany\", \"Chris\", \"Diana\", \"Eric\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let neighbors: Set = [\"Bethany\", \"Eric\", \"Forlani\", \"Greta\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let nonNeighbors = employees.subtracting(neighbors)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(nonNeighbors)]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"[\"Diana\", \"Chris\", \"Alicia\"]\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
+        key.offset: 3364,
+        key.length: 76,
+        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>subtracting</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.function.returntype></decl.function.method.instance>",
+        key.entities: [
+          {
+            key.kind: source.lang.swift.decl.var.local,
+            key.keyword: "_",
+            key.name: "other",
+            key.offset: 3401,
+            key.length: 17
+          }
+        ]
+      },
+      {
+        key.kind: source.lang.swift.decl.var.instance,
+        key.name: "isEmpty",
+        key.usr: "s:s10SetAlgebraPsE7isEmptySbvp::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPsE7isEmptySbvp",
+        key.doc.full_as_xml: "<Other><Name>isEmpty</Name><USR>s:s10SetAlgebraPsE7isEmptySbvp::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable var isEmpty: Bool { get }</Declaration><CommentParts><Abstract><Para>A Boolean value that indicates whether the set has no elements.</Para></Abstract></CommentParts></Other>",
+        key.offset: 3446,
+        key.length: 36,
+        key.fully_annotated_decl: "<decl.var.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>isEmpty</decl.name>: <decl.var.type><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
+      },
+      {
+        key.kind: source.lang.swift.decl.function.method.instance,
+        key.name: "isStrictSuperset(of:)",
+        key.usr: "s:s10SetAlgebraPsE16isStrictSuperset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPsE16isStrictSuperset2ofSbx_tF",
+        key.doc.full_as_xml: "<Function><Name>isStrictSuperset(of:)</Name><USR>s:s10SetAlgebraPsE16isStrictSuperset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func isStrictSuperset(of other: FooRuncingOptions) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value that indicates whether this set is a strict superset of the given set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A set of the same type as the current set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para><codeVoice>true</codeVoice> if the set is a strict superset of <codeVoice>other</codeVoice>; otherwise, <codeVoice>false</codeVoice>.</Para></ResultDiscussion><Discussion><Para>Set <emphasis>A</emphasis> is a strict superset of another set <emphasis>B</emphasis> if every member of <emphasis>B</emphasis> is also a member of <emphasis>A</emphasis> and <emphasis>A</emphasis> contains at least one element that is <emphasis>not</emphasis> a member of <emphasis>B</emphasis>.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let employees: Set = [\"Alicia\", \"Bethany\", \"Chris\", \"Diana\", \"Eric\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let attendees: Set = [\"Alicia\", \"Bethany\", \"Diana\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(employees.isStrictSuperset(of: attendees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// A set is never a strict superset of itself:]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(employees.isStrictSuperset(of: employees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"false\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
+        key.offset: 3488,
+        key.length: 69,
+        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>isStrictSuperset</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>of</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.method.instance>",
+        key.entities: [
+          {
+            key.kind: source.lang.swift.decl.var.local,
+            key.keyword: "of",
+            key.name: "other",
+            key.offset: 3531,
+            key.length: 17
+          }
+        ]
+      },
+      {
+        key.kind: source.lang.swift.decl.function.method.instance,
+        key.name: "isStrictSubset(of:)",
+        key.usr: "s:s10SetAlgebraPsE14isStrictSubset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions",
+        key.original_usr: "s:s10SetAlgebraPsE14isStrictSubset2ofSbx_tF",
+        key.doc.full_as_xml: "<Function><Name>isStrictSubset(of:)</Name><USR>s:s10SetAlgebraPsE14isStrictSubset2ofSbx_tF::SYNTHESIZED::c:@E@FooRuncingOptions</USR><Declaration>@inlinable func isStrictSubset(of other: FooRuncingOptions) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value that indicates whether this set is a strict subset of the given set.</Para></Abstract><Parameters><Parameter><Name>other</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A set of the same type as the current set.</Para></Discussion></Parameter></Parameters><ResultDiscussion><Para><codeVoice>true</codeVoice> if the set is a strict subset of <codeVoice>other</codeVoice>; otherwise, <codeVoice>false</codeVoice>.</Para></ResultDiscussion><Discussion><Para>Set <emphasis>A</emphasis> is a strict subset of another set <emphasis>B</emphasis> if every member of <emphasis>A</emphasis> is also a member of <emphasis>B</emphasis> and <emphasis>B</emphasis> contains at least one element that is not a member of <emphasis>A</emphasis>.</Para><CodeListing language=\"swift\"><zCodeLineNumbered><![CDATA[let employees: Set = [\"Alicia\", \"Bethany\", \"Chris\", \"Diana\", \"Eric\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[let attendees: Set = [\"Alicia\", \"Bethany\", \"Diana\"]]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(attendees.isStrictSubset(of: employees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"true\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// A set is never a strict subset of itself:]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[print(attendees.isStrictSubset(of: attendees))]]></zCodeLineNumbered><zCodeLineNumbered><![CDATA[// Prints \"false\"]]></zCodeLineNumbered><zCodeLineNumbered></zCodeLineNumbered></CodeListing></Discussion></CommentParts></Function>",
+        key.offset: 3563,
+        key.length: 67,
+        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>isStrictSubset</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>of</decl.var.parameter.argument_label> <decl.var.parameter.name>other</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooRuncingOptions\">FooRuncingOptions</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.method.instance>",
+        key.entities: [
+          {
+            key.kind: source.lang.swift.decl.var.local,
+            key.keyword: "of",
+            key.name: "other",
+            key.offset: 3604,
             key.length: 17
           }
         ]
@@ -6055,7 +6137,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.struct,
     key.name: "FooStruct1",
     key.usr: "c:@S@FooStruct1",
-    key.offset: 3495,
+    key.offset: 3634,
     key.length: 105,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>FooStruct1</decl.name></decl.struct>",
     key.entities: [
@@ -6063,7 +6145,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init()",
         key.usr: "s:So10FooStruct1VABycfc",
-        key.offset: 3520,
+        key.offset: 3659,
         key.length: 6,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>()</decl.function.constructor>"
       },
@@ -6071,7 +6153,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(x:y:)",
         key.usr: "s:So10FooStruct1V1x1yABs5Int32V_Sdtcfc",
-        key.offset: 3532,
+        key.offset: 3671,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>y</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Sd\">Double</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -6079,14 +6161,14 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "x",
             key.name: "x",
-            key.offset: 3542,
+            key.offset: 3681,
             key.length: 5
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "y",
             key.name: "y",
-            key.offset: 3554,
+            key.offset: 3693,
             key.length: 6
           }
         ]
@@ -6095,7 +6177,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "x",
         key.usr: "c:@S@FooStruct1@FI@x",
-        key.offset: 3567,
+        key.offset: 3706,
         key.length: 12,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>x</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type></decl.var.instance>"
       },
@@ -6103,7 +6185,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "y",
         key.usr: "c:@S@FooStruct1@FI@y",
-        key.offset: 3585,
+        key.offset: 3724,
         key.length: 13,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>y</decl.name>: <decl.var.type><ref.struct usr=\"s:Sd\">Double</ref.struct></decl.var.type></decl.var.instance>"
       }
@@ -6113,7 +6195,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.typealias,
     key.name: "FooStruct1Pointer",
     key.usr: "c:Foo.h@T@FooStruct1Pointer",
-    key.offset: 3602,
+    key.offset: 3741,
     key.length: 62,
     key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <decl.name>FooStruct1Pointer</decl.name> = <ref.struct usr=\"s:Sp\">UnsafeMutablePointer</ref.struct>&lt;<ref.struct usr=\"c:@S@FooStruct1\">FooStruct1</ref.struct>&gt;</decl.typealias>",
     key.conforms: [
@@ -6128,7 +6210,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.struct,
     key.name: "FooStruct2",
     key.usr: "c:@S@FooStruct2",
-    key.offset: 3666,
+    key.offset: 3805,
     key.length: 105,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>FooStruct2</decl.name></decl.struct>",
     key.entities: [
@@ -6136,7 +6218,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init()",
         key.usr: "s:So10FooStruct2VABycfc",
-        key.offset: 3691,
+        key.offset: 3830,
         key.length: 6,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>()</decl.function.constructor>"
       },
@@ -6144,7 +6226,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(x:y:)",
         key.usr: "s:So10FooStruct2V1x1yABs5Int32V_Sdtcfc",
-        key.offset: 3703,
+        key.offset: 3842,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>y</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Sd\">Double</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -6152,14 +6234,14 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "x",
             key.name: "x",
-            key.offset: 3713,
+            key.offset: 3852,
             key.length: 5
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "y",
             key.name: "y",
-            key.offset: 3725,
+            key.offset: 3864,
             key.length: 6
           }
         ]
@@ -6168,7 +6250,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "x",
         key.usr: "c:@S@FooStruct2@FI@x",
-        key.offset: 3738,
+        key.offset: 3877,
         key.length: 12,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>x</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type></decl.var.instance>"
       },
@@ -6176,7 +6258,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "y",
         key.usr: "c:@S@FooStruct2@FI@y",
-        key.offset: 3756,
+        key.offset: 3895,
         key.length: 13,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>y</decl.name>: <decl.var.type><ref.struct usr=\"s:Sd\">Double</ref.struct></decl.var.type></decl.var.instance>"
       }
@@ -6186,7 +6268,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.typealias,
     key.name: "FooStructTypedef1",
     key.usr: "c:Foo.h@T@FooStructTypedef1",
-    key.offset: 3773,
+    key.offset: 3912,
     key.length: 40,
     key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <decl.name>FooStructTypedef1</decl.name> = <ref.struct usr=\"c:@S@FooStruct2\">FooStruct2</ref.struct></decl.typealias>"
   },
@@ -6194,7 +6276,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.struct,
     key.name: "FooStructTypedef2",
     key.usr: "c:@SA@FooStructTypedef2",
-    key.offset: 3815,
+    key.offset: 3954,
     key.length: 112,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>FooStructTypedef2</decl.name></decl.struct>",
     key.entities: [
@@ -6202,7 +6284,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init()",
         key.usr: "s:So17FooStructTypedef2aABycfc",
-        key.offset: 3847,
+        key.offset: 3986,
         key.length: 6,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>()</decl.function.constructor>"
       },
@@ -6210,7 +6292,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(x:y:)",
         key.usr: "s:So17FooStructTypedef2a1x1yABs5Int32V_Sdtcfc",
-        key.offset: 3859,
+        key.offset: 3998,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>y</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Sd\">Double</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -6218,14 +6300,14 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "x",
             key.name: "x",
-            key.offset: 3869,
+            key.offset: 4008,
             key.length: 5
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "y",
             key.name: "y",
-            key.offset: 3881,
+            key.offset: 4020,
             key.length: 6
           }
         ]
@@ -6234,7 +6316,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "x",
         key.usr: "c:@SA@FooStructTypedef2@FI@x",
-        key.offset: 3894,
+        key.offset: 4033,
         key.length: 12,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>x</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type></decl.var.instance>"
       },
@@ -6242,7 +6324,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "y",
         key.usr: "c:@SA@FooStructTypedef2@FI@y",
-        key.offset: 3912,
+        key.offset: 4051,
         key.length: 13,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>y</decl.name>: <decl.var.type><ref.struct usr=\"s:Sd\">Double</ref.struct></decl.var.type></decl.var.instance>"
       }
@@ -6253,7 +6335,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "FooTypedef1",
     key.usr: "c:Foo.h@T@FooTypedef1",
     key.doc.full_as_xml: "<Typedef file=Foo.h line=\"60\" column=\"13\"><Name>FooTypedef1</Name><USR>c:Foo.h@T@FooTypedef1</USR><Declaration>typealias FooTypedef1 = Int32</Declaration><Abstract><Para> Aaa.  FooTypedef1.  Bbb.</Para></Abstract></Typedef>",
-    key.offset: 3929,
+    key.offset: 4068,
     key.length: 29,
     key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <decl.name>FooTypedef1</decl.name> = <ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.typealias>",
     key.conforms: [
@@ -6279,7 +6361,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "fooIntVar",
     key.usr: "c:@fooIntVar",
     key.doc.full_as_xml: "<Variable file=Foo.h line=\"63\" column=\"12\"><Name>fooIntVar</Name><USR>c:@fooIntVar</USR><Declaration>var fooIntVar: Int32</Declaration><Abstract><Para> Aaa.  fooIntVar.  Bbb.</Para></Abstract></Variable>",
-    key.offset: 3960,
+    key.offset: 4099,
     key.length: 20,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>fooIntVar</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type></decl.var.global>"
   },
@@ -6288,7 +6370,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "fooFunc1(_:)",
     key.usr: "c:@F@fooFunc1",
     key.doc.full_as_xml: "<Function file=Foo.h line=\"66\" column=\"5\"><Name>fooFunc1</Name><USR>c:@F@fooFunc1</USR><Declaration>func fooFunc1(_ a: Int32) -&gt; Int32</Declaration><Abstract><Para> Aaa.  fooFunc1.  Bbb.</Para></Abstract></Function>",
-    key.offset: 3982,
+    key.offset: 4121,
     key.length: 34,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFunc1</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>a</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.function.returntype></decl.function.free>",
     key.entities: [
@@ -6296,7 +6378,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "a",
-        key.offset: 4001,
+        key.offset: 4140,
         key.length: 5
       }
     ]
@@ -6305,14 +6387,14 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fooFunc1AnonymousParam(_:)",
     key.usr: "c:@F@fooFunc1AnonymousParam",
-    key.offset: 4018,
+    key.offset: 4157,
     key.length: 48,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFunc1AnonymousParam</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.function.returntype></decl.function.free>",
     key.entities: [
       {
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
-        key.offset: 4051,
+        key.offset: 4190,
         key.length: 5
       }
     ]
@@ -6321,7 +6403,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fooFunc3(_:_:_:_:)",
     key.usr: "c:@F@fooFunc3",
-    key.offset: 4068,
+    key.offset: 4207,
     key.length: 94,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFunc3</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>a</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>b</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Sf\">Float</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>c</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Sd\">Double</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>d</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Sp\">UnsafeMutablePointer</ref.struct>&lt;<ref.struct usr=\"s:s5Int32V\">Int32</ref.struct>&gt;!</decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.function.returntype></decl.function.free>",
     key.entities: [
@@ -6329,28 +6411,28 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "a",
-        key.offset: 4087,
+        key.offset: 4226,
         key.length: 5
       },
       {
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "b",
-        key.offset: 4099,
+        key.offset: 4238,
         key.length: 5
       },
       {
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "c",
-        key.offset: 4111,
+        key.offset: 4250,
         key.length: 6
       },
       {
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "d",
-        key.offset: 4124,
+        key.offset: 4263,
         key.length: 28
       }
     ]
@@ -6359,7 +6441,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fooFuncWithBlock(_:)",
     key.usr: "c:@F@fooFuncWithBlock",
-    key.offset: 4164,
+    key.offset: 4303,
     key.length: 49,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFuncWithBlock</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>blk</decl.var.parameter.name>: <decl.var.parameter.type>((<decl.var.parameter><decl.var.parameter.type><ref.struct usr=\"s:Sf\">Float</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.function.returntype>)!</decl.var.parameter.type></decl.var.parameter>)</decl.function.free>",
     key.entities: [
@@ -6367,7 +6449,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "blk",
-        key.offset: 4193,
+        key.offset: 4332,
         key.length: 19
       }
     ]
@@ -6376,7 +6458,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fooFuncWithFunctionPointer(_:)",
     key.usr: "c:@F@fooFuncWithFunctionPointer",
-    key.offset: 4215,
+    key.offset: 4354,
     key.length: 60,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFuncWithFunctionPointer</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>fptr</decl.var.parameter.name>: <decl.var.parameter.type>((<decl.var.parameter><decl.var.parameter.type><ref.struct usr=\"s:Sf\">Float</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.function.returntype>)!</decl.var.parameter.type></decl.var.parameter>)</decl.function.free>",
     key.entities: [
@@ -6384,7 +6466,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "fptr",
-        key.offset: 4255,
+        key.offset: 4394,
         key.length: 19
       }
     ]
@@ -6393,7 +6475,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fooFuncNoreturn1()",
     key.usr: "c:@F@fooFuncNoreturn1",
-    key.offset: 4277,
+    key.offset: 4416,
     key.length: 32,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFuncNoreturn1</decl.name>() -&gt; <decl.function.returntype><ref.enum usr=\"s:s5NeverO\">Never</ref.enum></decl.function.returntype></decl.function.free>"
   },
@@ -6401,7 +6483,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fooFuncNoreturn2()",
     key.usr: "c:@F@fooFuncNoreturn2",
-    key.offset: 4311,
+    key.offset: 4450,
     key.length: 32,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFuncNoreturn2</decl.name>() -&gt; <decl.function.returntype><ref.enum usr=\"s:s5NeverO\">Never</ref.enum></decl.function.returntype></decl.function.free>"
   },
@@ -6410,7 +6492,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "fooFuncWithComment1()",
     key.usr: "c:@F@fooFuncWithComment1",
     key.doc.full_as_xml: "<Function file=Foo.h line=\"89\" column=\"6\"><Name>fooFuncWithComment1</Name><USR>c:@F@fooFuncWithComment1</USR><Declaration>func fooFuncWithComment1()</Declaration><Abstract><Para> Aaa.  fooFuncWithComment1.  Bbb. Ccc.</Para></Abstract><Discussion><Para> Ddd.</Para></Discussion></Function>",
-    key.offset: 4345,
+    key.offset: 4484,
     key.length: 26,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFuncWithComment1</decl.name>()</decl.function.free>"
   },
@@ -6419,7 +6501,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "fooFuncWithComment2()",
     key.usr: "c:@F@fooFuncWithComment2",
     key.doc.full_as_xml: "<Function file=Foo.h line=\"94\" column=\"6\"><Name>fooFuncWithComment2</Name><USR>c:@F@fooFuncWithComment2</USR><Declaration>func fooFuncWithComment2()</Declaration><Abstract><Para>  Aaa.  fooFuncWithComment2.  Bbb.</Para></Abstract></Function>",
-    key.offset: 4373,
+    key.offset: 4512,
     key.length: 26,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFuncWithComment2</decl.name>()</decl.function.free>"
   },
@@ -6428,7 +6510,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "fooFuncWithComment3()",
     key.usr: "c:@F@fooFuncWithComment3",
     key.doc.full_as_xml: "<Function file=Foo.h line=\"102\" column=\"6\"><Name>fooFuncWithComment3</Name><USR>c:@F@fooFuncWithComment3</USR><Declaration>func fooFuncWithComment3()</Declaration><Abstract><Para> Aaa.  fooFuncWithComment3.  Bbb.</Para></Abstract><Discussion><Para> Ccc.</Para></Discussion></Function>",
-    key.offset: 4401,
+    key.offset: 4540,
     key.length: 26,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFuncWithComment3</decl.name>()</decl.function.free>"
   },
@@ -6437,7 +6519,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "fooFuncWithComment4()",
     key.usr: "c:@F@fooFuncWithComment4",
     key.doc.full_as_xml: "<Function file=Foo.h line=\"108\" column=\"6\"><Name>fooFuncWithComment4</Name><USR>c:@F@fooFuncWithComment4</USR><Declaration>func fooFuncWithComment4()</Declaration><Abstract><Para> Aaa.  fooFuncWithComment4.  Bbb.</Para></Abstract><Discussion><Para> Ddd.</Para></Discussion></Function>",
-    key.offset: 4429,
+    key.offset: 4568,
     key.length: 26,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFuncWithComment4</decl.name>()</decl.function.free>"
   },
@@ -6446,7 +6528,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "fooFuncWithComment5()",
     key.usr: "c:@F@fooFuncWithComment5",
     key.doc.full_as_xml: "<Function file=Foo.h line=\"114\" column=\"6\"><Name>fooFuncWithComment5</Name><USR>c:@F@fooFuncWithComment5</USR><Declaration>func fooFuncWithComment5()</Declaration><Abstract><Para> Aaa.  fooFuncWithComment5.  Bbb. Ccc.</Para></Abstract><Discussion><Para> Ddd.</Para></Discussion></Function>",
-    key.offset: 4457,
+    key.offset: 4596,
     key.length: 26,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooFuncWithComment5</decl.name>()</decl.function.free>"
   },
@@ -6455,7 +6537,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "redeclaredInMultipleModulesFunc1(_:)",
     key.usr: "c:@F@redeclaredInMultipleModulesFunc1",
     key.doc.full_as_xml: "<Function file=Foo.h line=\"118\" column=\"5\"><Name>redeclaredInMultipleModulesFunc1</Name><USR>c:@F@redeclaredInMultipleModulesFunc1</USR><Declaration>func redeclaredInMultipleModulesFunc1(_ a: Int32) -&gt; Int32</Declaration><Abstract><Para> Aaa.  redeclaredInMultipleModulesFunc1.  Bbb.</Para></Abstract></Function>",
-    key.offset: 4485,
+    key.offset: 4624,
     key.length: 58,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>redeclaredInMultipleModulesFunc1</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>a</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.function.returntype></decl.function.free>",
     key.entities: [
@@ -6463,7 +6545,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "a",
-        key.offset: 4528,
+        key.offset: 4667,
         key.length: 5
       }
     ]
@@ -6473,7 +6555,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "FooProtocolBase",
     key.usr: "c:objc(pl)FooProtocolBase",
     key.doc.full_as_xml: "<Other file=Foo.h line=\"121\" column=\"11\"><Name>FooProtocolBase</Name><USR>c:objc(pl)FooProtocolBase</USR><Declaration>protocol FooProtocolBase</Declaration><Abstract><Para> Aaa.  FooProtocolBase.  Bbb.</Para></Abstract></Other>",
-    key.offset: 4545,
+    key.offset: 4684,
     key.length: 301,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>FooProtocolBase</decl.name></decl.protocol>",
     key.entities: [
@@ -6482,7 +6564,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.name: "fooProtoFunc()",
         key.usr: "c:objc(pl)FooProtocolBase(im)fooProtoFunc",
         key.doc.full_as_xml: "<Function isInstanceMethod=\"1\" file=Foo.h line=\"125\" column=\"1\"><Name>fooProtoFunc</Name><USR>c:objc(pl)FooProtocolBase(im)fooProtoFunc</USR><Declaration>func fooProtoFunc()</Declaration><Abstract><Para> Aaa.  fooProtoFunc.  Bbb. Ccc.</Para></Abstract></Function>",
-        key.offset: 4577,
+        key.offset: 4716,
         key.length: 19,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooProtoFunc</decl.name>()</decl.function.method.instance>"
       },
@@ -6491,7 +6573,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.name: "fooProtoFuncWithExtraIndentation1()",
         key.usr: "c:objc(pl)FooProtocolBase(im)fooProtoFuncWithExtraIndentation1",
         key.doc.full_as_xml: "<Function isInstanceMethod=\"1\" file=Foo.h line=\"129\" column=\"3\"><Name>fooProtoFuncWithExtraIndentation1</Name><USR>c:objc(pl)FooProtocolBase(im)fooProtoFuncWithExtraIndentation1</USR><Declaration>func fooProtoFuncWithExtraIndentation1()</Declaration><Abstract><Para> Aaa.  fooProtoFuncWithExtraIndentation1.  Bbb. Ccc.</Para></Abstract></Function>",
-        key.offset: 4602,
+        key.offset: 4741,
         key.length: 40,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooProtoFuncWithExtraIndentation1</decl.name>()</decl.function.method.instance>"
       },
@@ -6500,7 +6582,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.name: "fooProtoFuncWithExtraIndentation2()",
         key.usr: "c:objc(pl)FooProtocolBase(im)fooProtoFuncWithExtraIndentation2",
         key.doc.full_as_xml: "<Function isInstanceMethod=\"1\" file=Foo.h line=\"135\" column=\"3\"><Name>fooProtoFuncWithExtraIndentation2</Name><USR>c:objc(pl)FooProtocolBase(im)fooProtoFuncWithExtraIndentation2</USR><Declaration>func fooProtoFuncWithExtraIndentation2()</Declaration><Abstract><Para> Aaa.  fooProtoFuncWithExtraIndentation2.  Bbb. Ccc.</Para></Abstract></Function>",
-        key.offset: 4648,
+        key.offset: 4787,
         key.length: 40,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooProtoFuncWithExtraIndentation2</decl.name>()</decl.function.method.instance>"
       },
@@ -6508,7 +6590,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.static,
         key.name: "fooProtoClassFunc()",
         key.usr: "c:objc(pl)FooProtocolBase(cm)fooProtoClassFunc",
-        key.offset: 4694,
+        key.offset: 4833,
         key.length: 31,
         key.fully_annotated_decl: "<decl.function.method.static><syntaxtype.keyword>static</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooProtoClassFunc</decl.name>()</decl.function.method.static>"
       },
@@ -6516,7 +6598,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "fooProperty1",
         key.usr: "c:objc(pl)FooProtocolBase(py)fooProperty1",
-        key.offset: 4731,
+        key.offset: 4870,
         key.length: 35,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>fooProperty1</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -6524,7 +6606,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "fooProperty2",
         key.usr: "c:objc(pl)FooProtocolBase(py)fooProperty2",
-        key.offset: 4772,
+        key.offset: 4911,
         key.length: 35,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>fooProperty2</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -6532,7 +6614,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "fooProperty3",
         key.usr: "c:objc(pl)FooProtocolBase(py)fooProperty3",
-        key.offset: 4813,
+        key.offset: 4952,
         key.length: 31,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>fooProperty3</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       }
@@ -6542,7 +6624,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.protocol,
     key.name: "FooProtocolDerived",
     key.usr: "c:objc(pl)FooProtocolDerived",
-    key.offset: 4848,
+    key.offset: 4987,
     key.length: 49,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>FooProtocolDerived</decl.name> : <ref.protocol usr=\"c:objc(pl)FooProtocolBase\">FooProtocolBase</ref.protocol></decl.protocol>",
     key.conforms: [
@@ -6557,7 +6639,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.class,
     key.name: "FooClassBase",
     key.usr: "c:objc(cs)FooClassBase",
-    key.offset: 4899,
+    key.offset: 5038,
     key.length: 392,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>FooClassBase</decl.name></decl.class>",
     key.entities: [
@@ -6565,7 +6647,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fooBaseInstanceFunc0()",
         key.usr: "c:objc(cs)FooClassBase(im)fooBaseInstanceFunc0",
-        key.offset: 4925,
+        key.offset: 5064,
         key.length: 27,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooBaseInstanceFunc0</decl.name>()</decl.function.method.instance>"
       },
@@ -6573,7 +6655,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fooBaseInstanceFunc1(_:)",
         key.usr: "c:objc(cs)FooClassBase(im)fooBaseInstanceFunc1:",
-        key.offset: 4958,
+        key.offset: 5097,
         key.length: 60,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooBaseInstanceFunc1</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>anObject</decl.var.parameter.name>: <decl.var.parameter.type><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.class usr=\"c:objc(cs)FooClassBase\">FooClassBase</ref.class>!</decl.function.returntype></decl.function.method.instance>",
         key.entities: [
@@ -6581,7 +6663,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "anObject",
-            key.offset: 4996,
+            key.offset: 5135,
             key.length: 4
           }
         ]
@@ -6590,7 +6672,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init()",
         key.usr: "c:objc(cs)FooClassBase(im)init",
-        key.offset: 5024,
+        key.offset: 5163,
         key.length: 7,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>!()</decl.function.constructor>"
       },
@@ -6598,7 +6680,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(float:)",
         key.usr: "c:objc(cs)FooClassBase(im)initWithFloat:",
-        key.offset: 5037,
+        key.offset: 5176,
         key.length: 33,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>convenience</syntaxtype.keyword> <syntaxtype.keyword>init</syntaxtype.keyword>!(<decl.var.parameter><decl.var.parameter.argument_label>float</decl.var.parameter.argument_label> <decl.var.parameter.name>f</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Sf\">Float</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -6606,7 +6688,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "float",
             key.name: "f",
-            key.offset: 5064,
+            key.offset: 5203,
             key.length: 5
           }
         ]
@@ -6615,7 +6697,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fooBaseInstanceFuncOverridden()",
         key.usr: "c:objc(cs)FooClassBase(im)fooBaseInstanceFuncOverridden",
-        key.offset: 5076,
+        key.offset: 5215,
         key.length: 36,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooBaseInstanceFuncOverridden</decl.name>()</decl.function.method.instance>"
       },
@@ -6623,7 +6705,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.class,
         key.name: "fooBaseClassFunc0()",
         key.usr: "c:objc(cs)FooClassBase(cm)fooBaseClassFunc0",
-        key.offset: 5118,
+        key.offset: 5257,
         key.length: 30,
         key.fully_annotated_decl: "<decl.function.method.class><syntaxtype.keyword>class</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooBaseClassFunc0</decl.name>()</decl.function.method.class>"
       },
@@ -6631,7 +6713,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "_internalMeth1()",
         key.usr: "c:objc(cs)FooClassBase(im)_internalMeth1",
-        key.offset: 5154,
+        key.offset: 5293,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>_internalMeth1</decl.name>() -&gt; <decl.function.returntype><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.function.returntype></decl.function.method.instance>"
       },
@@ -6639,7 +6721,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "_internalMeth2()",
         key.usr: "c:objc(cs)FooClassBase(im)_internalMeth2",
-        key.offset: 5189,
+        key.offset: 5328,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>_internalMeth2</decl.name>() -&gt; <decl.function.returntype><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.function.returntype></decl.function.method.instance>"
       },
@@ -6647,7 +6729,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "nonInternalMeth()",
         key.usr: "c:objc(cs)FooClassBase(im)nonInternalMeth",
-        key.offset: 5224,
+        key.offset: 5363,
         key.length: 30,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>nonInternalMeth</decl.name>() -&gt; <decl.function.returntype><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.function.returntype></decl.function.method.instance>"
       },
@@ -6655,7 +6737,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "_internalMeth3()",
         key.usr: "c:objc(cs)FooClassBase(im)_internalMeth3",
-        key.offset: 5260,
+        key.offset: 5399,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>_internalMeth3</decl.name>() -&gt; <decl.function.returntype><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.function.returntype></decl.function.method.instance>"
       }
@@ -6666,7 +6748,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.name: "FooClassDerived",
     key.usr: "c:objc(cs)FooClassDerived",
     key.doc.full_as_xml: "<Other file=Foo.h line=\"158\" column=\"12\"><Name>FooClassDerived</Name><USR>c:objc(cs)FooClassDerived</USR><Declaration>class FooClassDerived : FooClassBase, FooProtocolDerived</Declaration><Abstract><Para> Aaa.  FooClassDerived.  Bbb.</Para></Abstract></Other>",
-    key.offset: 5293,
+    key.offset: 5432,
     key.length: 352,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>FooClassDerived</decl.name> : <ref.class usr=\"c:objc(cs)FooClassBase\">FooClassBase</ref.class>, <ref.protocol usr=\"c:objc(pl)FooProtocolDerived\">FooProtocolDerived</ref.protocol></decl.class>",
     key.inherits: [
@@ -6688,7 +6770,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "fooProperty1",
         key.usr: "c:objc(cs)FooClassDerived(py)fooProperty1",
-        key.offset: 5357,
+        key.offset: 5496,
         key.length: 23,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>fooProperty1</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -6696,7 +6778,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "fooProperty2",
         key.usr: "c:objc(cs)FooClassDerived(py)fooProperty2",
-        key.offset: 5386,
+        key.offset: 5525,
         key.length: 23,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>fooProperty2</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -6704,7 +6786,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "fooProperty3",
         key.usr: "c:objc(cs)FooClassDerived(py)fooProperty3",
-        key.offset: 5415,
+        key.offset: 5554,
         key.length: 31,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>fooProperty3</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -6712,7 +6794,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fooInstanceFunc0()",
         key.usr: "c:objc(cs)FooClassDerived(im)fooInstanceFunc0",
-        key.offset: 5452,
+        key.offset: 5591,
         key.length: 23,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooInstanceFunc0</decl.name>()</decl.function.method.instance>"
       },
@@ -6720,7 +6802,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fooInstanceFunc1(_:)",
         key.usr: "c:objc(cs)FooClassDerived(im)fooInstanceFunc1:",
-        key.offset: 5481,
+        key.offset: 5620,
         key.length: 33,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooInstanceFunc1</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>a</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -6728,7 +6810,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "a",
-            key.offset: 5508,
+            key.offset: 5647,
             key.length: 5
           }
         ]
@@ -6737,7 +6819,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fooInstanceFunc2(_:withB:)",
         key.usr: "c:objc(cs)FooClassDerived(im)fooInstanceFunc2:withB:",
-        key.offset: 5520,
+        key.offset: 5659,
         key.length: 49,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooInstanceFunc2</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>a</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>withB</decl.var.parameter.argument_label> <decl.var.parameter.name>b</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -6745,14 +6827,14 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "a",
-            key.offset: 5547,
+            key.offset: 5686,
             key.length: 5
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "withB",
             key.name: "b",
-            key.offset: 5563,
+            key.offset: 5702,
             key.length: 5
           }
         ]
@@ -6761,7 +6843,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fooBaseInstanceFuncOverridden()",
         key.usr: "c:objc(cs)FooClassDerived(im)fooBaseInstanceFuncOverridden",
-        key.offset: 5575,
+        key.offset: 5714,
         key.length: 36,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooBaseInstanceFuncOverridden</decl.name>()</decl.function.method.instance>",
         key.inherits: [
@@ -6776,7 +6858,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.class,
         key.name: "fooClassFunc0()",
         key.usr: "c:objc(cs)FooClassDerived(cm)fooClassFunc0",
-        key.offset: 5617,
+        key.offset: 5756,
         key.length: 26,
         key.fully_annotated_decl: "<decl.function.method.class><syntaxtype.keyword>class</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooClassFunc0</decl.name>()</decl.function.method.class>"
       }
@@ -6786,7 +6868,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.typealias,
     key.name: "typedef_int_t",
     key.usr: "c:Foo.h@T@typedef_int_t",
-    key.offset: 5647,
+    key.offset: 5786,
     key.length: 31,
     key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <decl.name>typedef_int_t</decl.name> = <ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.typealias>",
     key.conforms: [
@@ -6811,7 +6893,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_1",
     key.usr: "c:Foo.h@3836@macro@FOO_MACRO_1",
-    key.offset: 5680,
+    key.offset: 5819,
     key.length: 30,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_1</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6819,7 +6901,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_2",
     key.usr: "c:Foo.h@3858@macro@FOO_MACRO_2",
-    key.offset: 5712,
+    key.offset: 5851,
     key.length: 30,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_2</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6827,7 +6909,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_3",
     key.usr: "c:Foo.h@3880@macro@FOO_MACRO_3",
-    key.offset: 5744,
+    key.offset: 5883,
     key.length: 30,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_3</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6835,7 +6917,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_4",
     key.usr: "c:Foo.h@3944@macro@FOO_MACRO_4",
-    key.offset: 5776,
+    key.offset: 5915,
     key.length: 31,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_4</decl.name>: <decl.var.type><ref.struct usr=\"s:s6UInt32V\">UInt32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6843,7 +6925,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_5",
     key.usr: "c:Foo.h@3976@macro@FOO_MACRO_5",
-    key.offset: 5809,
+    key.offset: 5948,
     key.length: 31,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_5</decl.name>: <decl.var.type><ref.struct usr=\"s:s6UInt64V\">UInt64</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6851,7 +6933,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_6",
     key.usr: "c:Foo.h@4018@macro@FOO_MACRO_6",
-    key.offset: 5842,
+    key.offset: 5981,
     key.length: 38,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_6</decl.name>: <decl.var.type><ref.typealias usr=\"c:Foo.h@T@typedef_int_t\">typedef_int_t</ref.typealias></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6859,7 +6941,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_7",
     key.usr: "c:Foo.h@4059@macro@FOO_MACRO_7",
-    key.offset: 5882,
+    key.offset: 6021,
     key.length: 38,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_7</decl.name>: <decl.var.type><ref.typealias usr=\"c:Foo.h@T@typedef_int_t\">typedef_int_t</ref.typealias></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6867,7 +6949,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_8",
     key.usr: "c:Foo.h@4100@macro@FOO_MACRO_8",
-    key.offset: 5922,
+    key.offset: 6061,
     key.length: 30,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_8</decl.name>: <decl.var.type><ref.typealias usr=\"s:s5CChara\">CChar</ref.typealias></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6875,7 +6957,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_9",
     key.usr: "c:Foo.h@4131@macro@FOO_MACRO_9",
-    key.offset: 5954,
+    key.offset: 6093,
     key.length: 30,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_9</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6883,7 +6965,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_10",
     key.usr: "c:Foo.h@4161@macro@FOO_MACRO_10",
-    key.offset: 5986,
+    key.offset: 6125,
     key.length: 31,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_10</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int16V\">Int16</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6891,7 +6973,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_11",
     key.usr: "c:Foo.h@4195@macro@FOO_MACRO_11",
-    key.offset: 6019,
+    key.offset: 6158,
     key.length: 29,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_11</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6899,7 +6981,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_OR",
     key.usr: "c:Foo.h@4228@macro@FOO_MACRO_OR",
-    key.offset: 6050,
+    key.offset: 6189,
     key.length: 31,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_OR</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6907,7 +6989,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_AND",
     key.usr: "c:Foo.h@4277@macro@FOO_MACRO_AND",
-    key.offset: 6083,
+    key.offset: 6222,
     key.length: 32,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_AND</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6915,7 +6997,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_BITWIDTH",
     key.usr: "c:Foo.h@4327@macro@FOO_MACRO_BITWIDTH",
-    key.offset: 6117,
+    key.offset: 6256,
     key.length: 38,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_BITWIDTH</decl.name>: <decl.var.type><ref.struct usr=\"s:s6UInt64V\">UInt64</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6923,7 +7005,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_SIGNED",
     key.usr: "c:Foo.h@4382@macro@FOO_MACRO_SIGNED",
-    key.offset: 6157,
+    key.offset: 6296,
     key.length: 36,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_SIGNED</decl.name>: <decl.var.type><ref.struct usr=\"s:s6UInt32V\">UInt32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6931,7 +7013,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_REDEF_1",
     key.usr: "c:Foo.h@4593@macro@FOO_MACRO_REDEF_1",
-    key.offset: 6195,
+    key.offset: 6334,
     key.length: 36,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_REDEF_1</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6939,7 +7021,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_MACRO_REDEF_2",
     key.usr: "c:Foo.h@4650@macro@FOO_MACRO_REDEF_2",
-    key.offset: 6233,
+    key.offset: 6372,
     key.length: 36,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_MACRO_REDEF_2</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>"
   },
@@ -6947,7 +7029,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "theLastDeclInFoo()",
     key.usr: "c:@F@theLastDeclInFoo",
-    key.offset: 6271,
+    key.offset: 6410,
     key.length: 23,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>theLastDeclInFoo</decl.name>()</decl.function.free>"
   },
@@ -6955,7 +7037,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "_internalTopLevelFunc()",
     key.usr: "c:@F@_internalTopLevelFunc",
-    key.offset: 6296,
+    key.offset: 6435,
     key.length: 28,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>_internalTopLevelFunc</decl.name>()</decl.function.free>"
   },
@@ -6963,7 +7045,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.struct,
     key.name: "_InternalStruct",
     key.usr: "c:@S@_InternalStruct",
-    key.offset: 6326,
+    key.offset: 6465,
     key.length: 78,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>_InternalStruct</decl.name></decl.struct>",
     key.entities: [
@@ -6971,7 +7053,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init()",
         key.usr: "s:So15_InternalStructVABycfc",
-        key.offset: 6356,
+        key.offset: 6495,
         key.length: 6,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>()</decl.function.constructor>"
       },
@@ -6979,7 +7061,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(x:)",
         key.usr: "s:So15_InternalStructV1xABs5Int32V_tcfc",
-        key.offset: 6368,
+        key.offset: 6507,
         key.length: 16,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -6987,7 +7069,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "x",
             key.name: "x",
-            key.offset: 6378,
+            key.offset: 6517,
             key.length: 5
           }
         ]
@@ -6996,7 +7078,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "x",
         key.usr: "c:@S@_InternalStruct@FI@x",
-        key.offset: 6390,
+        key.offset: 6529,
         key.length: 12,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>x</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type></decl.var.instance>"
       }
@@ -7004,7 +7086,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
   },
   {
     key.kind: source.lang.swift.decl.extension.class,
-    key.offset: 6406,
+    key.offset: 6545,
     key.length: 61,
     key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"c:objc(cs)FooClassBase\">FooClassBase</ref.class></decl.name></decl.extension.class>",
     key.extends: {
@@ -7017,7 +7099,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "_internalMeth1()",
         key.usr: "c:objc(cs)FooClassBase(im)_internalMeth1",
-        key.offset: 6436,
+        key.offset: 6575,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>_internalMeth1</decl.name>() -&gt; <decl.function.returntype><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.function.returntype></decl.function.method.instance>"
       }
@@ -7025,7 +7107,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
   },
   {
     key.kind: source.lang.swift.decl.extension.class,
-    key.offset: 6469,
+    key.offset: 6608,
     key.length: 97,
     key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"c:objc(cs)FooClassBase\">FooClassBase</ref.class></decl.name></decl.extension.class>",
     key.extends: {
@@ -7038,7 +7120,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "_internalMeth2()",
         key.usr: "c:objc(cs)FooClassBase(im)_internalMeth2",
-        key.offset: 6499,
+        key.offset: 6638,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>_internalMeth2</decl.name>() -&gt; <decl.function.returntype><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.function.returntype></decl.function.method.instance>"
       },
@@ -7046,7 +7128,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "nonInternalMeth()",
         key.usr: "c:objc(cs)FooClassBase(im)nonInternalMeth",
-        key.offset: 6534,
+        key.offset: 6673,
         key.length: 30,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>nonInternalMeth</decl.name>() -&gt; <decl.function.returntype><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.function.returntype></decl.function.method.instance>"
       }
@@ -7054,7 +7136,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
   },
   {
     key.kind: source.lang.swift.decl.extension.class,
-    key.offset: 6568,
+    key.offset: 6707,
     key.length: 61,
     key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"c:objc(cs)FooClassBase\">FooClassBase</ref.class></decl.name></decl.extension.class>",
     key.extends: {
@@ -7067,7 +7149,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "_internalMeth3()",
         key.usr: "c:objc(cs)FooClassBase(im)_internalMeth3",
-        key.offset: 6598,
+        key.offset: 6737,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>_internalMeth3</decl.name>() -&gt; <decl.function.returntype><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.function.returntype></decl.function.method.instance>"
       }
@@ -7077,7 +7159,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.protocol,
     key.name: "_InternalProt",
     key.usr: "c:objc(pl)_InternalProt",
-    key.offset: 6631,
+    key.offset: 6770,
     key.length: 26,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>_InternalProt</decl.name></decl.protocol>"
   },
@@ -7085,7 +7167,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.class,
     key.name: "ClassWithInternalProt",
     key.usr: "c:objc(cs)ClassWithInternalProt",
-    key.offset: 6659,
+    key.offset: 6798,
     key.length: 47,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>ClassWithInternalProt</decl.name> : <ref.protocol usr=\"c:objc(pl)_InternalProt\">_InternalProt</ref.protocol></decl.class>",
     key.conforms: [
@@ -7100,7 +7182,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.class,
     key.name: "FooClassPropertyOwnership",
     key.usr: "c:objc(cs)FooClassPropertyOwnership",
-    key.offset: 6708,
+    key.offset: 6847,
     key.length: 284,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>FooClassPropertyOwnership</decl.name> : <ref.class usr=\"c:objc(cs)FooClassBase\">FooClassBase</ref.class></decl.class>",
     key.inherits: [
@@ -7115,7 +7197,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "assignable",
         key.usr: "c:objc(cs)FooClassPropertyOwnership(py)assignable",
-        key.offset: 6762,
+        key.offset: 6901,
         key.length: 42,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>unowned(unsafe)</syntaxtype.keyword> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>assignable</decl.name>: <decl.var.type>AnyObject!</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -7123,7 +7205,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "unsafeAssignable",
         key.usr: "c:objc(cs)FooClassPropertyOwnership(py)unsafeAssignable",
-        key.offset: 6810,
+        key.offset: 6949,
         key.length: 48,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>unowned(unsafe)</syntaxtype.keyword> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>unsafeAssignable</decl.name>: <decl.var.type>AnyObject!</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -7131,7 +7213,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "retainable",
         key.usr: "c:objc(cs)FooClassPropertyOwnership(py)retainable",
-        key.offset: 6864,
+        key.offset: 7003,
         key.length: 20,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>retainable</decl.name>: <decl.var.type><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -7139,7 +7221,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "strongRef",
         key.usr: "c:objc(cs)FooClassPropertyOwnership(py)strongRef",
-        key.offset: 6890,
+        key.offset: 7029,
         key.length: 19,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>strongRef</decl.name>: <decl.var.type><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -7147,7 +7229,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "copyable",
         key.usr: "c:objc(cs)FooClassPropertyOwnership(py)copyable",
-        key.offset: 6915,
+        key.offset: 7054,
         key.length: 18,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>copyable</decl.name>: <decl.var.type><syntaxtype.keyword>Any</syntaxtype.keyword>!</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -7155,7 +7237,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "weakRef",
         key.usr: "c:objc(cs)FooClassPropertyOwnership(py)weakRef",
-        key.offset: 6939,
+        key.offset: 7078,
         key.length: 28,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>weak</syntaxtype.keyword> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>weakRef</decl.name>: <decl.var.type>AnyObject!</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -7163,7 +7245,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "scalar",
         key.usr: "c:objc(cs)FooClassPropertyOwnership(py)scalar",
-        key.offset: 6973,
+        key.offset: 7112,
         key.length: 17,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>scalar</decl.name>: <decl.var.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       }
@@ -7173,7 +7255,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FOO_NIL",
     key.usr: "c:Foo.h@5439@macro@FOO_NIL",
-    key.offset: 6994,
+    key.offset: 7133,
     key.length: 15,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FOO_NIL</decl.name>: <decl.var.type><tuple>()</tuple></decl.var.type></decl.var.global>",
     key.attributes: [
@@ -7189,7 +7271,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.class,
     key.name: "FooUnavailableMembers",
     key.usr: "c:objc(cs)FooUnavailableMembers",
-    key.offset: 7011,
+    key.offset: 7150,
     key.length: 451,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>FooUnavailableMembers</decl.name> : <ref.class usr=\"c:objc(cs)FooClassBase\">FooClassBase</ref.class></decl.class>",
     key.inherits: [
@@ -7204,7 +7286,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(int:)",
         key.usr: "c:objc(cs)FooUnavailableMembers(cm)unavailableMembersWithInt:",
-        key.offset: 7061,
+        key.offset: 7200,
         key.length: 31,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>convenience</syntaxtype.keyword> <syntaxtype.keyword>init</syntaxtype.keyword>!(<decl.var.parameter><decl.var.parameter.argument_label>int</decl.var.parameter.argument_label> <decl.var.parameter.name>i</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -7212,7 +7294,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "int",
             key.name: "i",
-            key.offset: 7086,
+            key.offset: 7225,
             key.length: 5
           }
         ]
@@ -7221,7 +7303,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "unavailable()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)unavailable",
-        key.offset: 7098,
+        key.offset: 7237,
         key.length: 18,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>unavailable</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7237,7 +7319,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "swiftUnavailable()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)swiftUnavailable",
-        key.offset: 7122,
+        key.offset: 7261,
         key.length: 23,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>swiftUnavailable</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7252,7 +7334,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "deprecated()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)deprecated",
-        key.offset: 7151,
+        key.offset: 7290,
         key.length: 17,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>deprecated</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7268,7 +7350,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "availabilityIntroduced()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)availabilityIntroduced",
-        key.offset: 7174,
+        key.offset: 7313,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>availabilityIntroduced</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7283,7 +7365,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "availabilityDeprecated()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)availabilityDeprecated",
-        key.offset: 7209,
+        key.offset: 7348,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>availabilityDeprecated</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7302,7 +7384,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "availabilityObsoleted()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)availabilityObsoleted",
-        key.offset: 7244,
+        key.offset: 7383,
         key.length: 28,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>availabilityObsoleted</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7318,7 +7400,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "availabilityUnavailable()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)availabilityUnavailable",
-        key.offset: 7278,
+        key.offset: 7417,
         key.length: 30,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>availabilityUnavailable</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7334,7 +7416,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "availabilityIntroducedMsg()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)availabilityIntroducedMsg",
-        key.offset: 7314,
+        key.offset: 7453,
         key.length: 32,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>availabilityIntroducedMsg</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7350,7 +7432,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "availabilityDeprecatedMsg()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)availabilityDeprecatedMsg",
-        key.offset: 7352,
+        key.offset: 7491,
         key.length: 32,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>availabilityDeprecatedMsg</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7369,7 +7451,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "availabilityObsoletedMsg()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)availabilityObsoletedMsg",
-        key.offset: 7390,
+        key.offset: 7529,
         key.length: 31,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>availabilityObsoletedMsg</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7386,7 +7468,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "availabilityUnavailableMsg()",
         key.usr: "c:objc(cs)FooUnavailableMembers(im)availabilityUnavailableMsg",
-        key.offset: 7427,
+        key.offset: 7566,
         key.length: 33,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>availabilityUnavailableMsg</decl.name>()</decl.function.method.instance>",
         key.attributes: [
@@ -7405,7 +7487,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.class,
     key.name: "FooCFType",
     key.usr: "c:Foo.h@T@FooCFTypeRef",
-    key.offset: 7464,
+    key.offset: 7603,
     key.length: 19,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>FooCFType</decl.name></decl.class>"
   },
@@ -7413,14 +7495,14 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "FooCFTypeRelease(_:)",
     key.usr: "c:@F@FooCFTypeRelease",
-    key.offset: 7485,
+    key.offset: 7624,
     key.length: 38,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>FooCFTypeRelease</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.class usr=\"c:Foo.h@T@FooCFTypeRef\">FooCFType</ref.class>!</decl.var.parameter.type></decl.var.parameter>)</decl.function.free>",
     key.entities: [
       {
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
-        key.offset: 7512,
+        key.offset: 7651,
         key.length: 10
       }
     ],
@@ -7437,7 +7519,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.enum,
     key.name: "ABAuthorizationStatus",
     key.usr: "c:@E@ABAuthorizationStatus",
-    key.offset: 7525,
+    key.offset: 7664,
     key.length: 274,
     key.fully_annotated_decl: "<decl.enum><syntaxtype.keyword>enum</syntaxtype.keyword> <decl.name>ABAuthorizationStatus</decl.name> : <ref.struct usr=\"s:Si\">Int</ref.struct></decl.enum>",
     key.inherits: [
@@ -7452,7 +7534,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.enumelement,
         key.name: "notDetermined",
         key.usr: "c:@E@ABAuthorizationStatus@kABAuthorizationStatusNotDetermined",
-        key.offset: 7565,
+        key.offset: 7704,
         key.length: 22,
         key.fully_annotated_decl: "<decl.enumelement><syntaxtype.keyword>case</syntaxtype.keyword> <decl.name>notDetermined</decl.name> = <syntaxtype.number>0</syntaxtype.number></decl.enumelement>",
         key.attributes: [
@@ -7467,7 +7549,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.enumelement,
         key.name: "restricted",
         key.usr: "c:@E@ABAuthorizationStatus@kABAuthorizationStatusRestricted",
-        key.offset: 7593,
+        key.offset: 7732,
         key.length: 19,
         key.fully_annotated_decl: "<decl.enumelement><syntaxtype.keyword>case</syntaxtype.keyword> <decl.name>restricted</decl.name> = <syntaxtype.number>1</syntaxtype.number></decl.enumelement>",
         key.attributes: [
@@ -7483,7 +7565,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.name: "hashValue",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp::SYNTHESIZED::c:@E@ABAuthorizationStatus",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp",
-        key.offset: 7618,
+        key.offset: 7757,
         key.length: 37,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>hashValue</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -7492,7 +7574,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.name: "hash(into:)",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF::SYNTHESIZED::c:@E@ABAuthorizationStatus",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF",
-        key.offset: 7661,
+        key.offset: 7800,
         key.length: 47,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>hash</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>into</decl.var.parameter.argument_label> <decl.var.parameter.name>hasher</decl.var.parameter.name>: <syntaxtype.keyword>inout</syntaxtype.keyword> <decl.var.parameter.type><ref.struct usr=\"s:s6HasherV\">Hasher</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -7500,7 +7582,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "into",
             key.name: "hasher",
-            key.offset: 7701,
+            key.offset: 7840,
             key.length: 6
           }
         ]
@@ -7511,7 +7593,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::c:@E@ABAuthorizationStatus",
         key.original_usr: "s:SQsE2neoiySbx_xtFZ",
         key.doc.full_as_xml: "<Function><Name>!=(_:_:)</Name><USR>s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::c:@E@ABAuthorizationStatus</USR><Declaration>static func != (lhs: ABAuthorizationStatus, rhs: ABAuthorizationStatus) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value indicating whether two values are not equal.</Para></Abstract><Parameters><Parameter><Name>lhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A value to compare.</Para></Discussion></Parameter><Parameter><Name>rhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>Another value to compare.</Para></Discussion></Parameter></Parameters><Discussion><Para>Inequality is the inverse of equality. For any values <codeVoice>a</codeVoice> and <codeVoice>b</codeVoice>, <codeVoice>a != b</codeVoice> implies that <codeVoice>a == b</codeVoice> is <codeVoice>false</codeVoice>.</Para><Para>This is the default implementation of the not-equal-to operator (<codeVoice>!=</codeVoice>) for any type that conforms to <codeVoice>Equatable</codeVoice>.</Para></Discussion></CommentParts></Function>",
-        key.offset: 7714,
+        key.offset: 7853,
         key.length: 83,
         key.fully_annotated_decl: "<decl.function.operator.infix><syntaxtype.keyword>static</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>!= </decl.name>(<decl.var.parameter><decl.var.parameter.name>lhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.enum usr=\"c:@E@ABAuthorizationStatus\">ABAuthorizationStatus</ref.enum></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.name>rhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.enum usr=\"c:@E@ABAuthorizationStatus\">ABAuthorizationStatus</ref.enum></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.operator.infix>",
         key.entities: [
@@ -7519,14 +7601,14 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "lhs",
-            key.offset: 7737,
+            key.offset: 7876,
             key.length: 21
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "rhs",
-            key.offset: 7767,
+            key.offset: 7906,
             key.length: 21
           }
         ]
@@ -7545,7 +7627,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fooSubFunc1(_:)",
     key.usr: "c:@F@fooSubFunc1",
-    key.offset: 7801,
+    key.offset: 7940,
     key.length: 37,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooSubFunc1</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>a</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.function.returntype></decl.function.free>",
     key.entities: [
@@ -7553,7 +7635,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "a",
-        key.offset: 7823,
+        key.offset: 7962,
         key.length: 5
       }
     ],
@@ -7563,7 +7645,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.struct,
     key.name: "FooSubEnum1",
     key.usr: "c:@E@FooSubEnum1",
-    key.offset: 7840,
+    key.offset: 7979,
     key.length: 320,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>FooSubEnum1</decl.name> : <ref.protocol usr=\"s:SH\">Hashable</ref.protocol>, <ref.protocol usr=\"s:SQ\">Equatable</ref.protocol>, <ref.protocol usr=\"s:SY\">RawRepresentable</ref.protocol></decl.struct>",
     key.conforms: [
@@ -7588,7 +7670,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(_:)",
         key.usr: "s:So11FooSubEnum1VyABs6UInt32Vcfc",
-        key.offset: 7906,
+        key.offset: 8045,
         key.length: 24,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>rawValue</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s6UInt32V\">UInt32</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -7596,7 +7678,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "rawValue",
-            key.offset: 7923,
+            key.offset: 8062,
             key.length: 6
           }
         ]
@@ -7605,7 +7687,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(rawValue:)",
         key.usr: "s:So11FooSubEnum1V8rawValueABs6UInt32V_tcfc",
-        key.offset: 7936,
+        key.offset: 8075,
         key.length: 31,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>rawValue</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:s6UInt32V\">UInt32</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -7613,7 +7695,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "rawValue",
             key.name: "rawValue",
-            key.offset: 7960,
+            key.offset: 8099,
             key.length: 6
           }
         ]
@@ -7622,7 +7704,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "rawValue",
         key.usr: "s:So11FooSubEnum1V8rawValues6UInt32Vvp",
-        key.offset: 7973,
+        key.offset: 8112,
         key.length: 20,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>rawValue</decl.name>: <decl.var.type><ref.struct usr=\"s:s6UInt32V\">UInt32</ref.struct></decl.var.type></decl.var.instance>"
       },
@@ -7631,7 +7713,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.name: "hashValue",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp::SYNTHESIZED::c:@E@FooSubEnum1",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp",
-        key.offset: 7999,
+        key.offset: 8138,
         key.length: 37,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>hashValue</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -7640,7 +7722,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.name: "hash(into:)",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF::SYNTHESIZED::c:@E@FooSubEnum1",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF",
-        key.offset: 8042,
+        key.offset: 8181,
         key.length: 47,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>hash</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>into</decl.var.parameter.argument_label> <decl.var.parameter.name>hasher</decl.var.parameter.name>: <syntaxtype.keyword>inout</syntaxtype.keyword> <decl.var.parameter.type><ref.struct usr=\"s:s6HasherV\">Hasher</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -7648,7 +7730,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "into",
             key.name: "hasher",
-            key.offset: 8082,
+            key.offset: 8221,
             key.length: 6
           }
         ]
@@ -7659,7 +7741,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::c:@E@FooSubEnum1",
         key.original_usr: "s:SQsE2neoiySbx_xtFZ",
         key.doc.full_as_xml: "<Function><Name>!=(_:_:)</Name><USR>s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::c:@E@FooSubEnum1</USR><Declaration>static func != (lhs: FooSubEnum1, rhs: FooSubEnum1) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value indicating whether two values are not equal.</Para></Abstract><Parameters><Parameter><Name>lhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A value to compare.</Para></Discussion></Parameter><Parameter><Name>rhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>Another value to compare.</Para></Discussion></Parameter></Parameters><Discussion><Para>Inequality is the inverse of equality. For any values <codeVoice>a</codeVoice> and <codeVoice>b</codeVoice>, <codeVoice>a != b</codeVoice> implies that <codeVoice>a == b</codeVoice> is <codeVoice>false</codeVoice>.</Para><Para>This is the default implementation of the not-equal-to operator (<codeVoice>!=</codeVoice>) for any type that conforms to <codeVoice>Equatable</codeVoice>.</Para></Discussion></CommentParts></Function>",
-        key.offset: 8095,
+        key.offset: 8234,
         key.length: 63,
         key.fully_annotated_decl: "<decl.function.operator.infix><syntaxtype.keyword>static</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>!= </decl.name>(<decl.var.parameter><decl.var.parameter.name>lhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooSubEnum1\">FooSubEnum1</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.name>rhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooSubEnum1\">FooSubEnum1</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.operator.infix>",
         key.entities: [
@@ -7667,14 +7749,14 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "lhs",
-            key.offset: 8118,
+            key.offset: 8257,
             key.length: 11
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "rhs",
-            key.offset: 8138,
+            key.offset: 8277,
             key.length: 11
           }
         ]
@@ -7686,7 +7768,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FooSubEnum1X",
     key.usr: "c:@E@FooSubEnum1@FooSubEnum1X",
-    key.offset: 8162,
+    key.offset: 8301,
     key.length: 37,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FooSubEnum1X</decl.name>: <decl.var.type><ref.struct usr=\"c:@E@FooSubEnum1\">FooSubEnum1</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>",
     key.modulename: "Foo.FooSub"
@@ -7695,7 +7777,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FooSubEnum1Y",
     key.usr: "c:@E@FooSubEnum1@FooSubEnum1Y",
-    key.offset: 8201,
+    key.offset: 8340,
     key.length: 37,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FooSubEnum1Y</decl.name>: <decl.var.type><ref.struct usr=\"c:@E@FooSubEnum1\">FooSubEnum1</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>",
     key.modulename: "Foo.FooSub"
@@ -7704,7 +7786,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FooSubUnnamedEnumeratorA1",
     key.usr: "c:@Ea@FooSubUnnamedEnumeratorA1@FooSubUnnamedEnumeratorA1",
-    key.offset: 8240,
+    key.offset: 8379,
     key.length: 42,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FooSubUnnamedEnumeratorA1</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>",
     key.modulename: "Foo.FooSub"
diff --git a/test/SourceKit/DocSupport/doc_clang_module.swift.sub.response b/test/SourceKit/DocSupport/doc_clang_module.swift.sub.response
index 23fb8f8a03c47..daaadda51cf4d 100644
--- a/test/SourceKit/DocSupport/doc_clang_module.swift.sub.response
+++ b/test/SourceKit/DocSupport/doc_clang_module.swift.sub.response
@@ -1,4 +1,3 @@
-
 func fooSubFunc1(_ a: Int32) -> Int32
 
 struct FooSubEnum1 : Hashable, Equatable, RawRepresentable {
@@ -26,314 +25,314 @@ var FooSubUnnamedEnumeratorA1: Int { get }
 [
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 1,
+    key.offset: 0,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 6,
+    key.offset: 5,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 18,
+    key.offset: 17,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 20,
+    key.offset: 19,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int32",
     key.usr: "s:s5Int32V",
-    key.offset: 23,
+    key.offset: 22,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int32",
     key.usr: "s:s5Int32V",
-    key.offset: 33,
+    key.offset: 32,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 40,
+    key.offset: 39,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 47,
+    key.offset: 46,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "Hashable",
     key.usr: "s:SH",
-    key.offset: 61,
+    key.offset: 60,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "Equatable",
     key.usr: "s:SQ",
-    key.offset: 71,
+    key.offset: 70,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "RawRepresentable",
     key.usr: "s:SY",
-    key.offset: 82,
+    key.offset: 81,
     key.length: 16
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 106,
+    key.offset: 105,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 111,
+    key.offset: 110,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 113,
+    key.offset: 112,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "UInt32",
     key.usr: "s:s6UInt32V",
-    key.offset: 123,
+    key.offset: 122,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 136,
+    key.offset: 135,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 141,
+    key.offset: 140,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 150,
+    key.offset: 149,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "UInt32",
     key.usr: "s:s6UInt32V",
-    key.offset: 160,
+    key.offset: 159,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 173,
+    key.offset: 172,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 177,
+    key.offset: 176,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "UInt32",
     key.usr: "s:s6UInt32V",
-    key.offset: 187,
+    key.offset: 186,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 199,
+    key.offset: 198,
     key.length: 10
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 210,
+    key.offset: 209,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 214,
+    key.offset: 213,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 225,
+    key.offset: 224,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 231,
+    key.offset: 230,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 242,
+    key.offset: 241,
     key.length: 10
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 253,
+    key.offset: 252,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 258,
+    key.offset: 257,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 263,
+    key.offset: 262,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 268,
+    key.offset: 267,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 276,
+    key.offset: 275,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Hasher",
     key.usr: "s:s6HasherV",
-    key.offset: 282,
+    key.offset: 281,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 295,
+    key.offset: 294,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 302,
+    key.offset: 301,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.operator,
-    key.offset: 307,
+    key.offset: 306,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 311,
+    key.offset: 310,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 313,
+    key.offset: 312,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "FooSubEnum1",
     key.usr: "c:@E@FooSubEnum1",
-    key.offset: 318,
+    key.offset: 317,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 331,
+    key.offset: 330,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 333,
+    key.offset: 332,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "FooSubEnum1",
     key.usr: "c:@E@FooSubEnum1",
-    key.offset: 338,
+    key.offset: 337,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Bool",
     key.usr: "s:Sb",
-    key.offset: 354,
+    key.offset: 353,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 362,
+    key.offset: 361,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 366,
+    key.offset: 365,
     key.length: 12
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "FooSubEnum1",
     key.usr: "c:@E@FooSubEnum1",
-    key.offset: 380,
+    key.offset: 379,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 394,
+    key.offset: 393,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 401,
+    key.offset: 400,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 405,
+    key.offset: 404,
     key.length: 12
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "FooSubEnum1",
     key.usr: "c:@E@FooSubEnum1",
-    key.offset: 419,
+    key.offset: 418,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 433,
+    key.offset: 432,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 440,
+    key.offset: 439,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 444,
+    key.offset: 443,
     key.length: 25
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 471,
+    key.offset: 470,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 477,
+    key.offset: 476,
     key.length: 3
   }
 ]
@@ -342,7 +341,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fooSubFunc1(_:)",
     key.usr: "c:@F@fooSubFunc1",
-    key.offset: 1,
+    key.offset: 0,
     key.length: 37,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooSubFunc1</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>a</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:s5Int32V\">Int32</ref.struct></decl.function.returntype></decl.function.free>",
     key.entities: [
@@ -350,7 +349,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "a",
-        key.offset: 23,
+        key.offset: 22,
         key.length: 5
       }
     ],
@@ -360,7 +359,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.struct,
     key.name: "FooSubEnum1",
     key.usr: "c:@E@FooSubEnum1",
-    key.offset: 40,
+    key.offset: 39,
     key.length: 320,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>FooSubEnum1</decl.name> : <ref.protocol usr=\"s:SH\">Hashable</ref.protocol>, <ref.protocol usr=\"s:SQ\">Equatable</ref.protocol>, <ref.protocol usr=\"s:SY\">RawRepresentable</ref.protocol></decl.struct>",
     key.conforms: [
@@ -385,7 +384,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(_:)",
         key.usr: "s:So11FooSubEnum1VyABs6UInt32Vcfc",
-        key.offset: 106,
+        key.offset: 105,
         key.length: 24,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>rawValue</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:s6UInt32V\">UInt32</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -393,7 +392,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "rawValue",
-            key.offset: 123,
+            key.offset: 122,
             key.length: 6
           }
         ]
@@ -402,7 +401,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(rawValue:)",
         key.usr: "s:So11FooSubEnum1V8rawValueABs6UInt32V_tcfc",
-        key.offset: 136,
+        key.offset: 135,
         key.length: 31,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>rawValue</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:s6UInt32V\">UInt32</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -410,7 +409,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "rawValue",
             key.name: "rawValue",
-            key.offset: 160,
+            key.offset: 159,
             key.length: 6
           }
         ]
@@ -419,7 +418,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "rawValue",
         key.usr: "s:So11FooSubEnum1V8rawValues6UInt32Vvp",
-        key.offset: 173,
+        key.offset: 172,
         key.length: 20,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>rawValue</decl.name>: <decl.var.type><ref.struct usr=\"s:s6UInt32V\">UInt32</ref.struct></decl.var.type></decl.var.instance>"
       },
@@ -428,7 +427,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.name: "hashValue",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp::SYNTHESIZED::c:@E@FooSubEnum1",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp",
-        key.offset: 199,
+        key.offset: 198,
         key.length: 37,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>hashValue</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -437,7 +436,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.name: "hash(into:)",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF::SYNTHESIZED::c:@E@FooSubEnum1",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF",
-        key.offset: 242,
+        key.offset: 241,
         key.length: 47,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>hash</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>into</decl.var.parameter.argument_label> <decl.var.parameter.name>hasher</decl.var.parameter.name>: <syntaxtype.keyword>inout</syntaxtype.keyword> <decl.var.parameter.type><ref.struct usr=\"s:s6HasherV\">Hasher</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -445,7 +444,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "into",
             key.name: "hasher",
-            key.offset: 282,
+            key.offset: 281,
             key.length: 6
           }
         ]
@@ -456,7 +455,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.usr: "s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::c:@E@FooSubEnum1",
         key.original_usr: "s:SQsE2neoiySbx_xtFZ",
         key.doc.full_as_xml: "<Function><Name>!=(_:_:)</Name><USR>s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::c:@E@FooSubEnum1</USR><Declaration>static func != (lhs: FooSubEnum1, rhs: FooSubEnum1) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value indicating whether two values are not equal.</Para></Abstract><Parameters><Parameter><Name>lhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A value to compare.</Para></Discussion></Parameter><Parameter><Name>rhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>Another value to compare.</Para></Discussion></Parameter></Parameters><Discussion><Para>Inequality is the inverse of equality. For any values <codeVoice>a</codeVoice> and <codeVoice>b</codeVoice>, <codeVoice>a != b</codeVoice> implies that <codeVoice>a == b</codeVoice> is <codeVoice>false</codeVoice>.</Para><Para>This is the default implementation of the not-equal-to operator (<codeVoice>!=</codeVoice>) for any type that conforms to <codeVoice>Equatable</codeVoice>.</Para></Discussion></CommentParts></Function>",
-        key.offset: 295,
+        key.offset: 294,
         key.length: 63,
         key.fully_annotated_decl: "<decl.function.operator.infix><syntaxtype.keyword>static</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>!= </decl.name>(<decl.var.parameter><decl.var.parameter.name>lhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooSubEnum1\">FooSubEnum1</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.name>rhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"c:@E@FooSubEnum1\">FooSubEnum1</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.operator.infix>",
         key.entities: [
@@ -464,14 +463,14 @@ var FooSubUnnamedEnumeratorA1: Int { get }
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "lhs",
-            key.offset: 318,
+            key.offset: 317,
             key.length: 11
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "rhs",
-            key.offset: 338,
+            key.offset: 337,
             key.length: 11
           }
         ]
@@ -483,7 +482,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FooSubEnum1X",
     key.usr: "c:@E@FooSubEnum1@FooSubEnum1X",
-    key.offset: 362,
+    key.offset: 361,
     key.length: 37,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FooSubEnum1X</decl.name>: <decl.var.type><ref.struct usr=\"c:@E@FooSubEnum1\">FooSubEnum1</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>",
     key.modulename: "Foo.FooSub"
@@ -492,7 +491,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FooSubEnum1Y",
     key.usr: "c:@E@FooSubEnum1@FooSubEnum1Y",
-    key.offset: 401,
+    key.offset: 400,
     key.length: 37,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FooSubEnum1Y</decl.name>: <decl.var.type><ref.struct usr=\"c:@E@FooSubEnum1\">FooSubEnum1</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>",
     key.modulename: "Foo.FooSub"
@@ -501,7 +500,7 @@ var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.name: "FooSubUnnamedEnumeratorA1",
     key.usr: "c:@Ea@FooSubUnnamedEnumeratorA1@FooSubUnnamedEnumeratorA1",
-    key.offset: 440,
+    key.offset: 439,
     key.length: 42,
     key.fully_annotated_decl: "<decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>FooSubUnnamedEnumeratorA1</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.global>",
     key.modulename: "Foo.FooSub"
diff --git a/test/SourceKit/DocSupport/doc_cross_import_common.swift.ClangFramework.response b/test/SourceKit/DocSupport/doc_cross_import_common.swift.ClangFramework.response
index 1a2790da5b052..79a38e1886aaa 100644
--- a/test/SourceKit/DocSupport/doc_cross_import_common.swift.ClangFramework.response
+++ b/test/SourceKit/DocSupport/doc_cross_import_common.swift.ClangFramework.response
@@ -1,11 +1,8 @@
-
 func fromClangFramework()
 
 
 // MARK: - BystandingLibrary Additions
 
-import SwiftOnoneSupport
-
 // Available when BystandingLibrary is imported with ClangFramework
 func fromClangFrameworkCrossImport()
 
@@ -13,47 +10,37 @@ func fromClangFrameworkCrossImport()
 [
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 1,
+    key.offset: 0,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 6,
+    key.offset: 5,
     key.length: 18
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 29,
+    key.offset: 28,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 32,
+    key.offset: 31,
     key.length: 35
   },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 69,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 76,
-    key.length: 17
-  },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 95,
+    key.offset: 68,
     key.length: 68
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 163,
+    key.offset: 136,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 168,
+    key.offset: 141,
     key.length: 29
   }
 ]
@@ -62,7 +49,7 @@ func fromClangFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fromClangFramework()",
     key.usr: "c:@F@fromClangFramework",
-    key.offset: 1,
+    key.offset: 0,
     key.length: 25,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromClangFramework</decl.name>()</decl.function.free>"
   },
@@ -70,7 +57,7 @@ func fromClangFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fromClangFrameworkCrossImport()",
     key.usr: "s:33_ClangFramework_BystandingLibrary04fromaB11CrossImportyyF",
-    key.offset: 163,
+    key.offset: 136,
     key.length: 36,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromClangFrameworkCrossImport</decl.name>()</decl.function.free>",
     key.required_bystanders: [
diff --git a/test/SourceKit/DocSupport/doc_cross_import_common.swift.OverlaidClangFramework.response b/test/SourceKit/DocSupport/doc_cross_import_common.swift.OverlaidClangFramework.response
index 2bae79e916ff1..32af4c70cb66e 100644
--- a/test/SourceKit/DocSupport/doc_cross_import_common.swift.OverlaidClangFramework.response
+++ b/test/SourceKit/DocSupport/doc_cross_import_common.swift.OverlaidClangFramework.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 func fromOverlaidClangFramework()
 
 func fromOverlaidClangFrameworkOverlay()
@@ -15,56 +13,46 @@ func fromOverlaidClangFrameworkCrossImport()
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
     key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 26,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 31,
+    key.offset: 5,
     key.length: 26
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 61,
+    key.offset: 35,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 66,
+    key.offset: 40,
     key.length: 33
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 104,
+    key.offset: 78,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 107,
+    key.offset: 81,
     key.length: 35
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 144,
+    key.offset: 118,
     key.length: 76
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 220,
+    key.offset: 194,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 225,
+    key.offset: 199,
     key.length: 37
   }
 ]
@@ -73,7 +61,7 @@ func fromOverlaidClangFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fromOverlaidClangFramework()",
     key.usr: "c:@F@fromOverlaidClangFramework",
-    key.offset: 26,
+    key.offset: 0,
     key.length: 33,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromOverlaidClangFramework</decl.name>()</decl.function.free>"
   },
@@ -81,7 +69,7 @@ func fromOverlaidClangFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fromOverlaidClangFrameworkOverlay()",
     key.usr: "s:22OverlaidClangFramework04fromabC7OverlayyyF",
-    key.offset: 61,
+    key.offset: 35,
     key.length: 40,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromOverlaidClangFrameworkOverlay</decl.name>()</decl.function.free>"
   },
@@ -89,7 +77,7 @@ func fromOverlaidClangFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fromOverlaidClangFrameworkCrossImport()",
     key.usr: "s:41_OverlaidClangFramework_BystandingLibrary04fromabC11CrossImportyyF",
-    key.offset: 220,
+    key.offset: 194,
     key.length: 44,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromOverlaidClangFrameworkCrossImport</decl.name>()</decl.function.free>",
     key.required_bystanders: [
diff --git a/test/SourceKit/DocSupport/doc_cross_import_common.swift.SwiftFramework.response b/test/SourceKit/DocSupport/doc_cross_import_common.swift.SwiftFramework.response
index c6cc47cc7d01f..f5bd69c639d96 100644
--- a/test/SourceKit/DocSupport/doc_cross_import_common.swift.SwiftFramework.response
+++ b/test/SourceKit/DocSupport/doc_cross_import_common.swift.SwiftFramework.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 func fromSwiftFramework()
 
 
@@ -13,46 +11,36 @@ func fromSwiftFrameworkCrossImport()
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
     key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 26,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 31,
+    key.offset: 5,
     key.length: 18
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 54,
+    key.offset: 28,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 57,
+    key.offset: 31,
     key.length: 35
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 94,
+    key.offset: 68,
     key.length: 68
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 162,
+    key.offset: 136,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 167,
+    key.offset: 141,
     key.length: 29
   }
 ]
@@ -61,7 +49,7 @@ func fromSwiftFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fromSwiftFramework()",
     key.usr: "s:14SwiftFramework04fromaB0yyF",
-    key.offset: 26,
+    key.offset: 0,
     key.length: 25,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromSwiftFramework</decl.name>()</decl.function.free>"
   },
@@ -69,7 +57,7 @@ func fromSwiftFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fromSwiftFrameworkCrossImport()",
     key.usr: "s:33_SwiftFramework_BystandingLibrary04fromaB11CrossImportyyF",
-    key.offset: 162,
+    key.offset: 136,
     key.length: 36,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromSwiftFrameworkCrossImport</decl.name>()</decl.function.free>",
     key.required_bystanders: [
diff --git a/test/SourceKit/DocSupport/doc_internal_closure_label.swift.response b/test/SourceKit/DocSupport/doc_internal_closure_label.swift.response
index 9366c16616d73..72056cfa9a4c1 100644
--- a/test/SourceKit/DocSupport/doc_internal_closure_label.swift.response
+++ b/test/SourceKit/DocSupport/doc_internal_closure_label.swift.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 func foo(_ callback: (_ myInternalParam: Int) -> Void)
 
 
@@ -7,55 +5,45 @@ func foo(_ callback: (_ myInternalParam: Int) -> Void)
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
     key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 26,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 31,
+    key.offset: 5,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 35,
+    key.offset: 9,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 37,
+    key.offset: 11,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 48,
+    key.offset: 22,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 50,
+    key.offset: 24,
     key.length: 15
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 67,
+    key.offset: 41,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.ref.typealias,
     key.name: "Void",
     key.usr: "s:s4Voida",
-    key.offset: 75,
+    key.offset: 49,
     key.length: 4
   }
 ]
@@ -64,7 +52,7 @@ func foo(_ callback: (_ myInternalParam: Int) -> Void)
     key.kind: source.lang.swift.decl.function.free,
     key.name: "foo(_:)",
     key.usr: "s:5label3fooyyySiXEF",
-    key.offset: 26,
+    key.offset: 0,
     key.length: 54,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>_</decl.var.parameter.argument_label> <decl.var.parameter.name>callback</decl.var.parameter.name>: <decl.var.parameter.type>(<decl.var.parameter>_ <decl.var.parameter.name>myInternalParam</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.typealias usr=\"s:s4Voida\">Void</ref.typealias></decl.function.returntype></decl.var.parameter.type></decl.var.parameter>)</decl.function.free>",
     key.entities: [
@@ -72,7 +60,7 @@ func foo(_ callback: (_ myInternalParam: Int) -> Void)
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "_",
         key.name: "callback",
-        key.offset: 47,
+        key.offset: 21,
         key.length: 32
       }
     ]
diff --git a/test/SourceKit/DocSupport/doc_swift_module.swift.response b/test/SourceKit/DocSupport/doc_swift_module.swift.response
index e598769642a2a..72de18f4ffced 100644
--- a/test/SourceKit/DocSupport/doc_swift_module.swift.response
+++ b/test/SourceKit/DocSupport/doc_swift_module.swift.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 struct Box<Wrapped> {
 
     func boxes() -> [cake.Box<Wrapped.Element>] where Wrapped : Sequence
@@ -183,1688 +181,1678 @@ func shouldPrintAnyAsKeyword(x x: Any)
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
     key.offset: 7,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 26,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 33,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 37,
+    key.offset: 11,
     key.length: 7
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 53,
+    key.offset: 27,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 58,
+    key.offset: 32,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 70,
+    key.offset: 44,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Box",
     key.usr: "s:4cake3BoxV",
-    key.offset: 75,
+    key.offset: 49,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "Wrapped",
     key.usr: "s:4cake3BoxV7Wrappedxmfp",
-    key.offset: 79,
+    key.offset: 53,
     key.length: 7
   },
   {
     key.kind: source.lang.swift.ref.associatedtype,
     key.name: "Element",
     key.usr: "s:ST7ElementQa",
-    key.offset: 87,
+    key.offset: 61,
     key.length: 7
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 97,
+    key.offset: 71,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "Wrapped",
     key.usr: "s:4cake3BoxV7Wrappedxmfp",
-    key.offset: 103,
+    key.offset: 77,
     key.length: 7
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "Sequence",
     key.usr: "s:ST",
-    key.offset: 113,
+    key.offset: 87,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 125,
+    key.offset: 99,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 131,
+    key.offset: 105,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 136,
+    key.offset: 110,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "Prot",
     key.usr: "s:4cake4ProtP",
-    key.offset: 141,
+    key.offset: 115,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 153,
+    key.offset: 127,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 163,
+    key.offset: 137,
     key.length: 7
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 173,
+    key.offset: 147,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 182,
+    key.offset: 156,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 186,
+    key.offset: 160,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 189,
+    key.offset: 163,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 198,
+    key.offset: 172,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 203,
+    key.offset: 177,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 214,
+    key.offset: 188,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 219,
+    key.offset: 193,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 224,
+    key.offset: 198,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 227,
+    key.offset: 201,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 231,
+    key.offset: 205,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 236,
+    key.offset: 210,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 239,
+    key.offset: 213,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 243,
+    key.offset: 217,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 253,
+    key.offset: 227,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 263,
+    key.offset: 237,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 265,
+    key.offset: 239,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 272,
+    key.offset: 246,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 280,
+    key.offset: 254,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 286,
+    key.offset: 260,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 297,
+    key.offset: 271,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 307,
+    key.offset: 281,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 313,
+    key.offset: 287,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Float",
     key.usr: "s:Sf",
-    key.offset: 316,
+    key.offset: 290,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 326,
+    key.offset: 300,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 332,
+    key.offset: 306,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 343,
+    key.offset: 317,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
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     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 2237,
+    key.offset: 2211,
     key.length: 3
   }
 ]
@@ -1878,7 +1866,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "Wrapped"
       }
     ],
-    key.offset: 26,
+    key.offset: 0,
     key.length: 97,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>Box</decl.name>&lt;<decl.generic_type_param usr=\"s:4cake3BoxV7Wrappedxmfp\"><decl.generic_type_param.name>Wrapped</decl.generic_type_param.name></decl.generic_type_param>&gt;</decl.struct>",
     key.entities: [
@@ -1891,7 +1879,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.description: "Wrapped : Sequence"
           }
         ],
-        key.offset: 53,
+        key.offset: 27,
         key.length: 68,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>boxes</decl.name>() -&gt; <decl.function.returntype>[<ref.struct usr=\"s:4cake3BoxV\">Box</ref.struct>&lt;<ref.generic_type_param usr=\"s:4cake3BoxV7Wrappedxmfp\">Wrapped</ref.generic_type_param>.<ref.associatedtype usr=\"s:ST7ElementQa\">Element</ref.associatedtype>&gt;]</decl.function.returntype> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake3BoxV7Wrappedxmfp\">Wrapped</ref.generic_type_param> : <ref.protocol usr=\"s:ST\">Sequence</ref.protocol></decl.generic_type_requirement></decl.function.method.instance>"
       }
@@ -1901,7 +1889,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.class,
     key.name: "C1",
     key.usr: "s:4cake2C1C",
-    key.offset: 125,
+    key.offset: 99,
     key.length: 346,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>C1</decl.name> : <ref.protocol usr=\"s:4cake4ProtP\">Prot</ref.protocol></decl.class>",
     key.conforms: [
@@ -1916,7 +1904,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.typealias,
         key.name: "Element",
         key.usr: "s:4cake2C1C7Elementa",
-        key.offset: 153,
+        key.offset: 127,
         key.length: 23,
         key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <ref.class usr=\"s:4cake2C1C\">C1</ref.class>.<decl.name>Element</decl.name> = <ref.struct usr=\"s:Si\">Int</ref.struct></decl.typealias>",
         key.conforms: [
@@ -1941,7 +1929,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "p",
         key.usr: "s:4cake2C1C1pSivp",
-        key.offset: 182,
+        key.offset: 156,
         key.length: 10,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>p</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type></decl.var.instance>",
         key.conforms: [
@@ -1956,7 +1944,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo()",
         key.usr: "s:4cake2C1C3fooyyF",
-        key.offset: 198,
+        key.offset: 172,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo</decl.name>()</decl.function.method.instance>",
         key.conforms: [
@@ -1971,7 +1959,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo1(i0:i1:)",
         key.usr: "s:4cake2C1C4foo12i02i1ySin_SihtF",
-        key.offset: 214,
+        key.offset: 188,
         key.length: 33,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo1</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>i0</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>i1</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1979,14 +1967,14 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "i0",
             key.name: "i0",
-            key.offset: 231,
+            key.offset: 205,
             key.length: 3
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "i1",
             key.name: "i1",
-            key.offset: 243,
+            key.offset: 217,
             key.length: 3
           }
         ]
@@ -1995,7 +1983,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.subscript,
         key.name: "subscript(_:)",
         key.usr: "s:4cake2C1CyS2icip",
-        key.offset: 253,
+        key.offset: 227,
         key.length: 38,
         key.fully_annotated_decl: "<decl.function.subscript><syntaxtype.keyword>subscript</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.name>index</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Si\">Int</ref.struct></decl.function.returntype> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.function.subscript>",
         key.entities: [
@@ -2003,7 +1991,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "index",
-            key.offset: 272,
+            key.offset: 246,
             key.length: 3
           }
         ]
@@ -2012,7 +2000,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.subscript,
         key.name: "subscript(index:)",
         key.usr: "s:4cake2C1C5indexSiSf_tcip",
-        key.offset: 297,
+        key.offset: 271,
         key.length: 40,
         key.fully_annotated_decl: "<decl.function.subscript><syntaxtype.keyword>subscript</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>index</decl.var.parameter.argument_label> <decl.var.parameter.name>i</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Sf\">Float</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Si\">Int</ref.struct></decl.function.returntype> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.function.subscript>",
         key.entities: [
@@ -2020,7 +2008,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "index",
             key.name: "i",
-            key.offset: 316,
+            key.offset: 290,
             key.length: 5
           }
         ]
@@ -2029,7 +2017,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.enum,
         key.name: "C1Cases",
         key.usr: "s:4cake2C1C0B5CasesO",
-        key.offset: 343,
+        key.offset: 317,
         key.length: 46,
         key.fully_annotated_decl: "<decl.enum><syntaxtype.keyword>enum</syntaxtype.keyword> <decl.name>C1Cases</decl.name> : <ref.struct usr=\"s:Si\">Int</ref.struct></decl.enum>",
         key.inherits: [
@@ -2044,7 +2032,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.enumelement,
             key.name: "case1",
             key.usr: "s:4cake2C1C0B5CasesO5case1yA2EmF",
-            key.offset: 373,
+            key.offset: 347,
             key.length: 10,
             key.fully_annotated_decl: "<decl.enumelement><syntaxtype.keyword>case</syntaxtype.keyword> <decl.name>case1</decl.name></decl.enumelement>"
           }
@@ -2055,7 +2043,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "extfoo()",
         key.usr: "s:4cake4ProtPAASi7ElementRtzrlE6extfooyyF::SYNTHESIZED::s:4cake2C1C",
         key.original_usr: "s:4cake4ProtPAASi7ElementRtzrlE6extfooyyF",
-        key.offset: 395,
+        key.offset: 369,
         key.length: 13,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>extfoo</decl.name>()</decl.function.method.instance>"
       },
@@ -2064,7 +2052,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "foo1()",
         key.usr: "s:4cake4ProtPAAE4foo1yyF::SYNTHESIZED::s:4cake2C1C",
         key.original_usr: "s:4cake4ProtPAAE4foo1yyF",
-        key.offset: 414,
+        key.offset: 388,
         key.length: 11,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo1</decl.name>()</decl.function.method.instance>"
       },
@@ -2073,7 +2061,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "subscript(_:)",
         key.usr: "s:4cake4ProtPAAEyS2icip::SYNTHESIZED::s:4cake2C1C",
         key.original_usr: "s:4cake4ProtPAAEyS2icip",
-        key.offset: 431,
+        key.offset: 405,
         key.length: 38,
         key.fully_annotated_decl: "<decl.function.subscript><syntaxtype.keyword>subscript</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.name>index</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Si\">Int</ref.struct></decl.function.returntype> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.function.subscript>",
         key.entities: [
@@ -2081,7 +2069,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "index",
-            key.offset: 450,
+            key.offset: 424,
             key.length: 3
           }
         ]
@@ -2091,7 +2079,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
   {
     key.kind: source.lang.swift.decl.extension.class,
     key.doc.full_as_xml: "<Other><Name></Name><Declaration>@available(macOS 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)\nextension C1</Declaration><CommentParts><Abstract><Para>some comments</Para></Abstract></CommentParts></Other>",
-    key.offset: 473,
+    key.offset: 447,
     key.length: 37,
     key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"s:4cake2C1C\">C1</ref.class></decl.name></decl.extension.class>",
     key.extends: {
@@ -2104,7 +2092,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "addition()",
         key.usr: "s:4cake2C1C8additionyyF",
-        key.offset: 493,
+        key.offset: 467,
         key.length: 15,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>addition</decl.name>()</decl.function.method.instance>"
       }
@@ -2134,7 +2122,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
   },
   {
     key.kind: source.lang.swift.decl.extension.class,
-    key.offset: 512,
+    key.offset: 486,
     key.length: 109,
     key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"s:4cake2C1C\">C1</ref.class></decl.name> : <ref.protocol usr=\"s:4cake2P4P\">P4</ref.protocol></decl.extension.class>",
     key.conforms: [
@@ -2154,7 +2142,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "C1foo()",
         key.usr: "s:4cake2C1C5C1fooyyF",
-        key.offset: 542,
+        key.offset: 516,
         key.length: 12,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>C1foo</decl.name>()</decl.function.method.instance>"
       },
@@ -2162,7 +2150,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.struct,
         key.name: "C1S1",
         key.usr: "s:4cake2C1C0B2S1V",
-        key.offset: 560,
+        key.offset: 534,
         key.length: 59,
         key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>C1S1</decl.name></decl.struct>",
         key.entities: [
@@ -2170,7 +2158,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.function.method.instance,
             key.name: "C1S1foo(a:)",
             key.usr: "s:4cake2C1C0B2S1V0B5S1foo1ayAA2P4_p_tF",
-            key.offset: 583,
+            key.offset: 557,
             key.length: 30,
             key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>C1S1foo</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>a</decl.var.parameter.argument_label>: <decl.var.parameter.type>any <ref.protocol usr=\"s:4cake2P4P\">P4</ref.protocol></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
             key.entities: [
@@ -2178,7 +2166,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
                 key.kind: source.lang.swift.decl.var.local,
                 key.keyword: "a",
                 key.name: "a",
-                key.offset: 601,
+                key.offset: 575,
                 key.length: 11
               }
             ]
@@ -2189,7 +2177,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
   },
   {
     key.kind: source.lang.swift.decl.extension.enum,
-    key.offset: 623,
+    key.offset: 597,
     key.length: 197,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.class usr=\"s:4cake2C1C\">C1</ref.class>.<ref.enum usr=\"s:4cake2C1C0B5CasesO\">C1Cases</ref.enum>",
     key.extends: {
@@ -2203,7 +2191,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "hashValue",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp::SYNTHESIZED::s:4cake2C1C0B5CasesO",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp",
-        key.offset: 651,
+        key.offset: 625,
         key.length: 37,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>hashValue</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -2212,7 +2200,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "hash(into:)",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF::SYNTHESIZED::s:4cake2C1C0B5CasesO",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF",
-        key.offset: 694,
+        key.offset: 668,
         key.length: 47,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>hash</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>into</decl.var.parameter.argument_label> <decl.var.parameter.name>hasher</decl.var.parameter.name>: <syntaxtype.keyword>inout</syntaxtype.keyword> <decl.var.parameter.type><ref.struct usr=\"s:s6HasherV\">Hasher</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -2220,7 +2208,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "into",
             key.name: "hasher",
-            key.offset: 734,
+            key.offset: 708,
             key.length: 6
           }
         ]
@@ -2231,7 +2219,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.usr: "s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::s:4cake2C1C0B5CasesO",
         key.original_usr: "s:SQsE2neoiySbx_xtFZ",
         key.doc.full_as_xml: "<Function><Name>!=(_:_:)</Name><USR>s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::s:4cake2C1C0B5CasesO</USR><Declaration>static func != (lhs: cake.C1.C1Cases, rhs: cake.C1.C1Cases) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value indicating whether two values are not equal.</Para></Abstract><Parameters><Parameter><Name>lhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A value to compare.</Para></Discussion></Parameter><Parameter><Name>rhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>Another value to compare.</Para></Discussion></Parameter></Parameters><Discussion><Para>Inequality is the inverse of equality. For any values <codeVoice>a</codeVoice> and <codeVoice>b</codeVoice>, <codeVoice>a != b</codeVoice> implies that <codeVoice>a == b</codeVoice> is <codeVoice>false</codeVoice>.</Para><Para>This is the default implementation of the not-equal-to operator (<codeVoice>!=</codeVoice>) for any type that conforms to <codeVoice>Equatable</codeVoice>.</Para></Discussion></CommentParts></Function>",
-        key.offset: 747,
+        key.offset: 721,
         key.length: 71,
         key.fully_annotated_decl: "<decl.function.operator.infix><syntaxtype.keyword>static</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>!= </decl.name>(<decl.var.parameter><decl.var.parameter.name>lhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.class usr=\"s:4cake2C1C\">C1</ref.class>.<ref.enum usr=\"s:4cake2C1C0B5CasesO\">C1Cases</ref.enum></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.name>rhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.class usr=\"s:4cake2C1C\">C1</ref.class>.<ref.enum usr=\"s:4cake2C1C0B5CasesO\">C1Cases</ref.enum></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.operator.infix>",
         key.entities: [
@@ -2239,14 +2227,14 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "lhs",
-            key.offset: 770,
+            key.offset: 744,
             key.length: 15
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "rhs",
-            key.offset: 794,
+            key.offset: 768,
             key.length: 15
           }
         ]
@@ -2257,7 +2245,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.class,
     key.name: "C2",
     key.usr: "s:4cake2C2C",
-    key.offset: 822,
+    key.offset: 796,
     key.length: 40,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>C2</decl.name> : <ref.class usr=\"s:4cake2C1C\">C1</ref.class></decl.class>",
     key.inherits: [
@@ -2272,7 +2260,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "C2foo()",
         key.usr: "s:4cake2C2C5C2fooyyF",
-        key.offset: 848,
+        key.offset: 822,
         key.length: 12,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>C2foo</decl.name>()</decl.function.method.instance>"
       }
@@ -2282,7 +2270,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.enum,
     key.name: "MyEnum",
     key.usr: "s:4cake6MyEnumO",
-    key.offset: 864,
+    key.offset: 838,
     key.length: 201,
     key.fully_annotated_decl: "<decl.enum><syntaxtype.keyword>enum</syntaxtype.keyword> <decl.name>MyEnum</decl.name> : <ref.struct usr=\"s:Si\">Int</ref.struct></decl.enum>",
     key.inherits: [
@@ -2297,7 +2285,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.enumelement,
         key.name: "Blah",
         key.usr: "s:4cake6MyEnumO4BlahyA2CmF",
-        key.offset: 889,
+        key.offset: 863,
         key.length: 9,
         key.fully_annotated_decl: "<decl.enumelement><syntaxtype.keyword>case</syntaxtype.keyword> <decl.name>Blah</decl.name></decl.enumelement>"
       },
@@ -2306,7 +2294,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "hashValue",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp::SYNTHESIZED::s:4cake6MyEnumO",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE04hashB0Sivp",
-        key.offset: 904,
+        key.offset: 878,
         key.length: 37,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>hashValue</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -2315,7 +2303,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "hash(into:)",
         key.usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF::SYNTHESIZED::s:4cake6MyEnumO",
         key.original_usr: "s:SYsSHRzSH8RawValueSYRpzrlE4hash4intoys6HasherVz_tF",
-        key.offset: 947,
+        key.offset: 921,
         key.length: 47,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@inlinable</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>hash</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>into</decl.var.parameter.argument_label> <decl.var.parameter.name>hasher</decl.var.parameter.name>: <syntaxtype.keyword>inout</syntaxtype.keyword> <decl.var.parameter.type><ref.struct usr=\"s:s6HasherV\">Hasher</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -2323,7 +2311,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "into",
             key.name: "hasher",
-            key.offset: 987,
+            key.offset: 961,
             key.length: 6
           }
         ]
@@ -2334,7 +2322,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.usr: "s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::s:4cake6MyEnumO",
         key.original_usr: "s:SQsE2neoiySbx_xtFZ",
         key.doc.full_as_xml: "<Function><Name>!=(_:_:)</Name><USR>s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::s:4cake6MyEnumO</USR><Declaration>static func != (lhs: cake.MyEnum, rhs: cake.MyEnum) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value indicating whether two values are not equal.</Para></Abstract><Parameters><Parameter><Name>lhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A value to compare.</Para></Discussion></Parameter><Parameter><Name>rhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>Another value to compare.</Para></Discussion></Parameter></Parameters><Discussion><Para>Inequality is the inverse of equality. For any values <codeVoice>a</codeVoice> and <codeVoice>b</codeVoice>, <codeVoice>a != b</codeVoice> implies that <codeVoice>a == b</codeVoice> is <codeVoice>false</codeVoice>.</Para><Para>This is the default implementation of the not-equal-to operator (<codeVoice>!=</codeVoice>) for any type that conforms to <codeVoice>Equatable</codeVoice>.</Para></Discussion></CommentParts></Function>",
-        key.offset: 1000,
+        key.offset: 974,
         key.length: 63,
         key.fully_annotated_decl: "<decl.function.operator.infix><syntaxtype.keyword>static</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>!= </decl.name>(<decl.var.parameter><decl.var.parameter.name>lhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.enum usr=\"s:4cake6MyEnumO\">MyEnum</ref.enum></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.name>rhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.enum usr=\"s:4cake6MyEnumO\">MyEnum</ref.enum></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.operator.infix>",
         key.entities: [
@@ -2342,14 +2330,14 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "lhs",
-            key.offset: 1023,
+            key.offset: 997,
             key.length: 11
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "rhs",
-            key.offset: 1043,
+            key.offset: 1017,
             key.length: 11
           }
         ]
@@ -2360,7 +2348,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P",
     key.usr: "s:4cake1PP",
-    key.offset: 1067,
+    key.offset: 1041,
     key.length: 30,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P</decl.name></decl.protocol>",
     key.entities: [
@@ -2368,7 +2356,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo()",
         key.usr: "s:4cake1PP3fooyyF",
-        key.offset: 1085,
+        key.offset: 1059,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo</decl.name>()</decl.function.method.instance>"
       }
@@ -2376,7 +2364,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
   },
   {
     key.kind: source.lang.swift.decl.extension.protocol,
-    key.offset: 1099,
+    key.offset: 1073,
     key.length: 54,
     key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:4cake1PP\">P</ref.protocol></decl.name></decl.extension.protocol>",
     key.extends: {
@@ -2394,7 +2382,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.description: "Self : Equatable"
           }
         ],
-        key.offset: 1118,
+        key.offset: 1092,
         key.length: 33,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>bar</decl.name>() <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake1PP4Selfxmfp\">Self</ref.generic_type_param> : <ref.protocol usr=\"s:SQ\">Equatable</ref.protocol></decl.generic_type_requirement></decl.function.method.instance>"
       }
@@ -2404,7 +2392,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P2",
     key.usr: "c:@M@cake@objc(pl)P2",
-    key.offset: 1155,
+    key.offset: 1129,
     key.length: 53,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@objc</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P2</decl.name></decl.protocol>",
     key.entities: [
@@ -2412,7 +2400,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo1()",
         key.usr: "c:@M@cake@objc(pl)P2(im)foo1",
-        key.offset: 1180,
+        key.offset: 1154,
         key.length: 26,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.attribute.builtin><syntaxtype.attribute.name>@objc</syntaxtype.attribute.name></syntaxtype.attribute.builtin> <syntaxtype.keyword>optional</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo1</decl.name>()</decl.function.method.instance>",
         key.is_optional: 1
@@ -2423,7 +2411,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P3",
     key.usr: "s:4cake2P3P",
-    key.offset: 1210,
+    key.offset: 1184,
     key.length: 37,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P3</decl.name></decl.protocol>",
     key.entities: [
@@ -2431,7 +2419,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.associatedtype,
         key.name: "T",
         key.usr: "s:4cake2P3P1TQa",
-        key.offset: 1229,
+        key.offset: 1203,
         key.length: 16,
         key.fully_annotated_decl: "<decl.associatedtype><syntaxtype.keyword>associatedtype</syntaxtype.keyword> <decl.name>T</decl.name></decl.associatedtype>"
       }
@@ -2441,7 +2429,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P4",
     key.usr: "s:4cake2P4P",
-    key.offset: 1249,
+    key.offset: 1223,
     key.length: 15,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P4</decl.name></decl.protocol>"
   },
@@ -2449,7 +2437,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P5",
     key.usr: "s:4cake2P5P",
-    key.offset: 1266,
+    key.offset: 1240,
     key.length: 43,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P5</decl.name></decl.protocol>",
     key.entities: [
@@ -2457,7 +2445,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.associatedtype,
         key.name: "Element",
         key.usr: "s:4cake2P5P7ElementQa",
-        key.offset: 1285,
+        key.offset: 1259,
         key.length: 22,
         key.fully_annotated_decl: "<decl.associatedtype><syntaxtype.keyword>associatedtype</syntaxtype.keyword> <decl.name>Element</decl.name></decl.associatedtype>"
       }
@@ -2467,7 +2455,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P6",
     key.usr: "s:4cake2P6P",
-    key.offset: 1311,
+    key.offset: 1285,
     key.length: 25,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P6</decl.name> : <ref.protocol usr=\"s:4cake2P5P\">P5</ref.protocol></decl.protocol>",
     key.conforms: [
@@ -2480,7 +2468,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
   },
   {
     key.kind: source.lang.swift.decl.extension.protocol,
-    key.offset: 1338,
+    key.offset: 1312,
     key.length: 53,
     key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:4cake2P6P\">P6</ref.protocol></decl.name></decl.extension.protocol>",
     key.extends: {
@@ -2493,7 +2481,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "null",
         key.usr: "s:4cake2P6PAAE4null7ElementQzSgvp",
-        key.offset: 1358,
+        key.offset: 1332,
         key.length: 31,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>null</decl.name>: <decl.var.type><ref.generic_type_param usr=\"s:4cake2P6P4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:4cake2P5P7ElementQa\">Element</ref.associatedtype>?</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       }
@@ -2503,7 +2491,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.protocol,
     key.name: "Prot",
     key.usr: "s:4cake4ProtP",
-    key.offset: 1393,
+    key.offset: 1367,
     key.length: 102,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>Prot</decl.name></decl.protocol>",
     key.entities: [
@@ -2511,7 +2499,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.associatedtype,
         key.name: "Element",
         key.usr: "s:4cake4ProtP7ElementQa",
-        key.offset: 1414,
+        key.offset: 1388,
         key.length: 22,
         key.fully_annotated_decl: "<decl.associatedtype><syntaxtype.keyword>associatedtype</syntaxtype.keyword> <decl.name>Element</decl.name></decl.associatedtype>"
       },
@@ -2519,7 +2507,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "p",
         key.usr: "s:4cake4ProtP1pSivp",
-        key.offset: 1442,
+        key.offset: 1416,
         key.length: 18,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>p</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -2527,7 +2515,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo()",
         key.usr: "s:4cake4ProtP3fooyyF",
-        key.offset: 1466,
+        key.offset: 1440,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo</decl.name>()</decl.function.method.instance>"
       },
@@ -2535,7 +2523,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo1()",
         key.usr: "s:4cake4ProtP4foo1yyF",
-        key.offset: 1482,
+        key.offset: 1456,
         key.length: 11,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo1</decl.name>()</decl.function.method.instance>"
       }
@@ -2543,7 +2531,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
   },
   {
     key.kind: source.lang.swift.decl.extension.protocol,
-    key.offset: 1497,
+    key.offset: 1471,
     key.length: 79,
     key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:4cake4ProtP\">Prot</ref.protocol></decl.name></decl.extension.protocol>",
     key.extends: {
@@ -2557,7 +2545,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "foo1()",
         key.usr: "s:4cake4ProtPAAE4foo1yyF",
         key.default_implementation_of: "s:4cake4ProtP4foo1yyF",
-        key.offset: 1519,
+        key.offset: 1493,
         key.length: 11,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo1</decl.name>()</decl.function.method.instance>"
       },
@@ -2565,7 +2553,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.subscript,
         key.name: "subscript(_:)",
         key.usr: "s:4cake4ProtPAAEyS2icip",
-        key.offset: 1536,
+        key.offset: 1510,
         key.length: 38,
         key.fully_annotated_decl: "<decl.function.subscript><syntaxtype.keyword>subscript</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.name>index</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Si\">Int</ref.struct></decl.function.returntype> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.function.subscript>",
         key.entities: [
@@ -2573,7 +2561,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "index",
-            key.offset: 1555,
+            key.offset: 1529,
             key.length: 3
           }
         ]
@@ -2587,7 +2575,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.description: "Self.Element == Int"
       }
     ],
-    key.offset: 1578,
+    key.offset: 1552,
     key.length: 63,
     key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:4cake4ProtP\">Prot</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake4ProtP4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:4cake4ProtP7ElementQa\">Element</ref.associatedtype> == <ref.struct usr=\"s:Si\">Int</ref.struct></decl.generic_type_requirement></decl.extension.protocol>",
     key.extends: {
@@ -2600,7 +2588,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "extfoo()",
         key.usr: "s:4cake4ProtPAASi7ElementRtzrlE6extfooyyF",
-        key.offset: 1626,
+        key.offset: 1600,
         key.length: 13,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>extfoo</decl.name>()</decl.function.method.instance>"
       }
@@ -2610,7 +2598,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.struct,
     key.name: "S1",
     key.usr: "s:4cake2S1V",
-    key.offset: 1643,
+    key.offset: 1617,
     key.length: 142,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>S1</decl.name></decl.struct>",
     key.entities: [
@@ -2618,7 +2606,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.enum,
         key.name: "SE",
         key.usr: "s:4cake2S1V2SEO",
-        key.offset: 1660,
+        key.offset: 1634,
         key.length: 63,
         key.fully_annotated_decl: "<decl.enum><syntaxtype.keyword>enum</syntaxtype.keyword> <ref.struct usr=\"s:4cake2S1V\">S1</ref.struct>.<decl.name>SE</decl.name></decl.enum>",
         key.entities: [
@@ -2626,7 +2614,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.enumelement,
             key.name: "a",
             key.usr: "s:4cake2S1V2SEO1ayA2EmF",
-            key.offset: 1679,
+            key.offset: 1653,
             key.length: 6,
             key.fully_annotated_decl: "<decl.enumelement><syntaxtype.keyword>case</syntaxtype.keyword> <decl.name>a</decl.name></decl.enumelement>"
           },
@@ -2634,7 +2622,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.enumelement,
             key.name: "b",
             key.usr: "s:4cake2S1V2SEO1byA2EmF",
-            key.offset: 1695,
+            key.offset: 1669,
             key.length: 6,
             key.fully_annotated_decl: "<decl.enumelement><syntaxtype.keyword>case</syntaxtype.keyword> <decl.name>b</decl.name></decl.enumelement>"
           },
@@ -2642,7 +2630,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.enumelement,
             key.name: "c",
             key.usr: "s:4cake2S1V2SEO1cyA2EmF",
-            key.offset: 1711,
+            key.offset: 1685,
             key.length: 6,
             key.fully_annotated_decl: "<decl.enumelement><syntaxtype.keyword>case</syntaxtype.keyword> <decl.name>c</decl.name></decl.enumelement>"
           }
@@ -2652,7 +2640,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo1()",
         key.usr: "s:4cake2S1V4foo1yyF",
-        key.offset: 1729,
+        key.offset: 1703,
         key.length: 11,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo1</decl.name>()</decl.function.method.instance>"
       },
@@ -2660,7 +2648,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.struct,
         key.name: "S2",
         key.usr: "s:4cake2S1V2S2V",
-        key.offset: 1746,
+        key.offset: 1720,
         key.length: 37,
         key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>S2</decl.name></decl.struct>",
         key.entities: [
@@ -2668,7 +2656,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.instance,
             key.name: "b",
             key.usr: "s:4cake2S1V2S2V1bSivp",
-            key.offset: 1767,
+            key.offset: 1741,
             key.length: 10,
             key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>let</syntaxtype.keyword> <decl.name>b</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type></decl.var.instance>"
           }
@@ -2678,7 +2666,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
   },
   {
     key.kind: source.lang.swift.decl.extension.enum,
-    key.offset: 1787,
+    key.offset: 1761,
     key.length: 86,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"s:4cake2S1V\">S1</ref.struct>.<ref.enum usr=\"s:4cake2S1V2SEO\">SE</ref.enum>",
     key.extends: {
@@ -2693,7 +2681,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.usr: "s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::s:4cake2S1V2SEO",
         key.original_usr: "s:SQsE2neoiySbx_xtFZ",
         key.doc.full_as_xml: "<Function><Name>!=(_:_:)</Name><USR>s:SQsE2neoiySbx_xtFZ::SYNTHESIZED::s:4cake2S1V2SEO</USR><Declaration>static func != (lhs: cake.S1.SE, rhs: cake.S1.SE) -&gt; Bool</Declaration><CommentParts><Abstract><Para>Returns a Boolean value indicating whether two values are not equal.</Para></Abstract><Parameters><Parameter><Name>lhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>A value to compare.</Para></Discussion></Parameter><Parameter><Name>rhs</Name><Direction isExplicit=\"0\">in</Direction><Discussion><Para>Another value to compare.</Para></Discussion></Parameter></Parameters><Discussion><Para>Inequality is the inverse of equality. For any values <codeVoice>a</codeVoice> and <codeVoice>b</codeVoice>, <codeVoice>a != b</codeVoice> implies that <codeVoice>a == b</codeVoice> is <codeVoice>false</codeVoice>.</Para><Para>This is the default implementation of the not-equal-to operator (<codeVoice>!=</codeVoice>) for any type that conforms to <codeVoice>Equatable</codeVoice>.</Para></Discussion></CommentParts></Function>",
-        key.offset: 1810,
+        key.offset: 1784,
         key.length: 61,
         key.fully_annotated_decl: "<decl.function.operator.infix><syntaxtype.keyword>static</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>!= </decl.name>(<decl.var.parameter><decl.var.parameter.name>lhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:4cake2S1V\">S1</ref.struct>.<ref.enum usr=\"s:4cake2S1V2SEO\">SE</ref.enum></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.name>rhs</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:4cake2S1V\">S1</ref.struct>.<ref.enum usr=\"s:4cake2S1V2SEO\">SE</ref.enum></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Sb\">Bool</ref.struct></decl.function.returntype></decl.function.operator.infix>",
         key.entities: [
@@ -2701,14 +2689,14 @@ func shouldPrintAnyAsKeyword(x x: Any)
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "lhs",
-            key.offset: 1833,
+            key.offset: 1807,
             key.length: 10
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "rhs",
-            key.offset: 1852,
+            key.offset: 1826,
             key.length: 10
           }
         ]
@@ -2719,7 +2707,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.struct,
     key.name: "S2",
     key.usr: "s:4cake2S2V",
-    key.offset: 1875,
+    key.offset: 1849,
     key.length: 50,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>S2</decl.name> : <ref.protocol usr=\"s:4cake2P3P\">P3</ref.protocol></decl.struct>",
     key.conforms: [
@@ -2734,7 +2722,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.typealias,
         key.name: "T",
         key.usr: "s:4cake2S2V1Ta",
-        key.offset: 1902,
+        key.offset: 1876,
         key.length: 21,
         key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <ref.struct usr=\"s:4cake2S2V\">S2</ref.struct>.<decl.name>T</decl.name> = <ref.struct usr=\"s:4cake2S2V\">S2</ref.struct></decl.typealias>",
         key.conforms: [
@@ -2761,7 +2749,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.description: "Wrapped : P5"
       }
     ],
-    key.offset: 1927,
+    key.offset: 1901,
     key.length: 97,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>S3</decl.name>&lt;<decl.generic_type_param usr=\"s:4cake2S3V7Wrappedxmfp\"><decl.generic_type_param.name>Wrapped</decl.generic_type_param.name></decl.generic_type_param>&gt; : <ref.protocol usr=\"s:4cake2P5P\">P5</ref.protocol> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake2S3V7Wrappedxmfp\">Wrapped</ref.generic_type_param> : <ref.protocol usr=\"s:4cake2P5P\">P5</ref.protocol></decl.generic_type_requirement></decl.struct>",
     key.conforms: [
@@ -2776,7 +2764,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.typealias,
         key.name: "Element",
         key.usr: "s:4cake2S3V7Elementa",
-        key.offset: 1987,
+        key.offset: 1961,
         key.length: 35,
         key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <ref.struct usr=\"s:4cake2S3V\">S3</ref.struct>&lt;<ref.generic_type_param usr=\"s:4cake2S3V7Wrappedxmfp\">Wrapped</ref.generic_type_param>&gt;.<decl.name>Element</decl.name> = <ref.generic_type_param usr=\"s:4cake2S3V7Wrappedxmfp\">Wrapped</ref.generic_type_param>.<ref.associatedtype usr=\"s:4cake2P5P7ElementQa\">Element</ref.associatedtype></decl.typealias>",
         key.conforms: [
@@ -2801,7 +2789,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.description: "Wrapped : P6"
       }
     ],
-    key.offset: 2026,
+    key.offset: 2000,
     key.length: 80,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"s:4cake2S3V\">S3</ref.struct> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake2S3V7Wrappedxmfp\">Wrapped</ref.generic_type_param> : <ref.protocol usr=\"s:4cake2P6P\">P6</ref.protocol></decl.generic_type_requirement>",
     key.extends: {
@@ -2815,7 +2803,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.name: "null",
         key.usr: "s:4cake2P6PAAE4null7ElementQzSgvp::SYNTHESIZED::s:4cake2S3V",
         key.original_usr: "s:4cake2P6PAAE4null7ElementQzSgvp",
-        key.offset: 2070,
+        key.offset: 2044,
         key.length: 34,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>null</decl.name>: <decl.var.type><ref.generic_type_param usr=\"s:4cake2S3V7Wrappedxmfp\">Wrapped</ref.generic_type_param>.<ref.associatedtype usr=\"s:4cake2P5P7ElementQa\">Element</ref.associatedtype>?</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       }
@@ -2844,7 +2832,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.description: "T1.Element == Int"
       }
     ],
-    key.offset: 2108,
+    key.offset: 2082,
     key.length: 93,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>genfoo</decl.name>&lt;<decl.generic_type_param usr=\"s:4cake6genfoo1x1yyx_q_tAA4ProtRzAA2C1CRb_Si7ElementRtzr0_lF2T1L_xmfp\"><decl.generic_type_param.name>T1</decl.generic_type_param.name></decl.generic_type_param>, <decl.generic_type_param usr=\"s:4cake6genfoo1x1yyx_q_tAA4ProtRzAA2C1CRb_Si7ElementRtzr0_lF2T2L_q_mfp\"><decl.generic_type_param.name>T2</decl.generic_type_param.name></decl.generic_type_param>&gt;(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label> <decl.var.parameter.name>ix</decl.var.parameter.name>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:4cake6genfoo1x1yyx_q_tAA4ProtRzAA2C1CRb_Si7ElementRtzr0_lF2T1L_xmfp\">T1</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>y</decl.var.parameter.argument_label> <decl.var.parameter.name>iy</decl.var.parameter.name>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:4cake6genfoo1x1yyx_q_tAA4ProtRzAA2C1CRb_Si7ElementRtzr0_lF2T2L_q_mfp\">T2</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>) <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake6genfoo1x1yyx_q_tAA4ProtRzAA2C1CRb_Si7ElementRtzr0_lF2T1L_xmfp\">T1</ref.generic_type_param> : <ref.protocol usr=\"s:4cake4ProtP\">Prot</ref.protocol></decl.generic_type_requirement>, <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake6genfoo1x1yyx_q_tAA4ProtRzAA2C1CRb_Si7ElementRtzr0_lF2T2L_q_mfp\">T2</ref.generic_type_param> : <ref.class usr=\"s:4cake2C1C\">C1</ref.class></decl.generic_type_requirement>, <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake6genfoo1x1yyx_q_tAA4ProtRzAA2C1CRb_Si7ElementRtzr0_lF2T1L_xmfp\">T1</ref.generic_type_param>.<ref.associatedtype usr=\"s:4cake4ProtP7ElementQa\">Element</ref.associatedtype> == <ref.struct usr=\"s:Si\">Int</ref.struct></decl.generic_type_requirement></decl.function.free>",
     key.entities: [
@@ -2852,14 +2840,14 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "x",
         key.name: "ix",
-        key.offset: 2134,
+        key.offset: 2108,
         key.length: 2
       },
       {
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "y",
         key.name: "iy",
-        key.offset: 2144,
+        key.offset: 2118,
         key.length: 2
       }
     ]
@@ -2868,7 +2856,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
     key.kind: source.lang.swift.decl.function.free,
     key.name: "shouldPrintAnyAsKeyword(x:)",
     key.usr: "s:4cake23shouldPrintAnyAsKeyword1xyyp_tF",
-    key.offset: 2203,
+    key.offset: 2177,
     key.length: 38,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>shouldPrintAnyAsKeyword</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><syntaxtype.keyword>Any</syntaxtype.keyword></decl.var.parameter.type></decl.var.parameter>)</decl.function.free>",
     key.entities: [
@@ -2876,7 +2864,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "x",
         key.name: "x",
-        key.offset: 2237,
+        key.offset: 2211,
         key.length: 3
       }
     ]
diff --git a/test/SourceKit/DocSupport/doc_swift_module1.swift.response b/test/SourceKit/DocSupport/doc_swift_module1.swift.response
index 0725bd006d587..b625b63f45370 100644
--- a/test/SourceKit/DocSupport/doc_swift_module1.swift.response
+++ b/test/SourceKit/DocSupport/doc_swift_module1.swift.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 class InitClassImpl : cake1.InitProto {
 
     required init(x x: Int)
@@ -80,610 +78,600 @@ extension Dictionary.Keys where Key : cake1.P1 {
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
     key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 26,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 32,
+    key.offset: 6,
     key.length: 13
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 48,
+    key.offset: 22,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "InitProto",
     key.usr: "s:5cake19InitProtoP",
-    key.offset: 54,
+    key.offset: 28,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 71,
+    key.offset: 45,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 80,
+    key.offset: 54,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 85,
+    key.offset: 59,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 87,
+    key.offset: 61,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 90,
+    key.offset: 64,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 100,
+    key.offset: 74,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 112,
+    key.offset: 86,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 122,
+    key.offset: 96,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 131,
+    key.offset: 105,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 148,
+    key.offset: 122,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 153,
+    key.offset: 127,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 155,
+    key.offset: 129,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 158,
+    key.offset: 132,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 166,
+    key.offset: 140,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "InitProto",
     key.usr: "s:5cake19InitProtoP",
-    key.offset: 176,
+    key.offset: 150,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 193,
+    key.offset: 167,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 203,
+    key.offset: 177,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 210,
+    key.offset: 184,
     key.length: 14
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 227,
+    key.offset: 201,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "InitProto",
     key.usr: "s:5cake19InitProtoP",
-    key.offset: 233,
+    key.offset: 207,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 250,
+    key.offset: 224,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 255,
+    key.offset: 229,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 257,
+    key.offset: 231,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 260,
+    key.offset: 234,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 270,
+    key.offset: 244,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 280,
+    key.offset: 254,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 289,
+    key.offset: 263,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 299,
+    key.offset: 273,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 304,
+    key.offset: 278,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 316,
+    key.offset: 290,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 320,
+    key.offset: 294,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 325,
+    key.offset: 299,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 331,
+    key.offset: 305,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 335,
+    key.offset: 309,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 346,
+    key.offset: 320,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 351,
+    key.offset: 325,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 356,
+    key.offset: 330,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 358,
+    key.offset: 332,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 361,
+    key.offset: 335,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 366,
+    key.offset: 340,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 368,
+    key.offset: 342,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 371,
+    key.offset: 345,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 381,
+    key.offset: 355,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 391,
+    key.offset: 365,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 393,
+    key.offset: 367,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 396,
+    key.offset: 370,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 404,
+    key.offset: 378,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 410,
+    key.offset: 384,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 414,
+    key.offset: 388,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 425,
+    key.offset: 399,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 430,
+    key.offset: 404,
     key.length: 13
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 449,
+    key.offset: 423,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 458,
+    key.offset: 432,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 463,
+    key.offset: 437,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "P1",
     key.usr: "s:5cake12P1P",
-    key.offset: 469,
+    key.offset: 443,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 479,
+    key.offset: 453,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 484,
+    key.offset: 458,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 496,
+    key.offset: 470,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 501,
+    key.offset: 475,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 511,
+    key.offset: 485,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "P2",
     key.usr: "s:5cake12P2P",
-    key.offset: 521,
+    key.offset: 495,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 531,
+    key.offset: 505,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 536,
+    key.offset: 510,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 548,
+    key.offset: 522,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 552,
+    key.offset: 526,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 557,
+    key.offset: 531,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 566,
+    key.offset: 540,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 571,
+    key.offset: 545,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 576,
+    key.offset: 550,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 578,
+    key.offset: 552,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 581,
+    key.offset: 555,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 586,
+    key.offset: 560,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 588,
+    key.offset: 562,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 591,
+    key.offset: 565,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 601,
+    key.offset: 575,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 611,
+    key.offset: 585,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 613,
+    key.offset: 587,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 616,
+    key.offset: 590,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
-    key.offset: 624,
+    key.offset: 598,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 631,
+    key.offset: 605,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "P2",
     key.usr: "s:5cake12P2P",
-    key.offset: 641,
+    key.offset: 615,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 644,
+    key.offset: 618,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "Self",
     key.usr: "s:5cake12P2P4Selfxmfp",
-    key.offset: 650,
+    key.offset: 624,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 657,
+    key.offset: 631,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "P3",
     key.usr: "s:5cake12P3P",
-    key.offset: 663,
+    key.offset: 637,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 673,
+    key.offset: 647,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 678,
+    key.offset: 652,
     key.length: 13
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 697,
+    key.offset: 671,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 706,
+    key.offset: 680,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 716,
+    key.offset: 690,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 721,
+    key.offset: 695,
     key.length: 10
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 737,
+    key.offset: 711,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Dictionary",
     key.usr: "s:SD",
-    key.offset: 747,
+    key.offset: 721,
     key.length: 10
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Keys",
     key.usr: "s:SD4KeysV",
-    key.offset: 758,
+    key.offset: 732,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 770,
+    key.offset: 744,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 775,
+    key.offset: 749,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 784,
+    key.offset: 758,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Dictionary",
     key.usr: "s:SD",
-    key.offset: 794,
+    key.offset: 768,
     key.length: 10
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Keys",
     key.usr: "s:SD4KeysV",
-    key.offset: 805,
+    key.offset: 779,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 810,
+    key.offset: 784,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "Key",
     key.usr: "s:SD3Keyxmfp",
-    key.offset: 816,
+    key.offset: 790,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 822,
+    key.offset: 796,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "P1",
     key.usr: "s:5cake12P1P",
-    key.offset: 828,
+    key.offset: 802,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 838,
+    key.offset: 812,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 843,
+    key.offset: 817,
     key.length: 3
   }
 ]
@@ -692,7 +680,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
     key.kind: source.lang.swift.decl.class,
     key.name: "InitClassImpl",
     key.usr: "s:5cake113InitClassImplC",
-    key.offset: 26,
+    key.offset: 0,
     key.length: 94,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>InitClassImpl</decl.name> : <ref.protocol usr=\"s:5cake19InitProtoP\">InitProto</ref.protocol></decl.class>",
     key.conforms: [
@@ -707,7 +695,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(x:)",
         key.usr: "s:5cake113InitClassImplC1xACSi_tcfc",
-        key.offset: 71,
+        key.offset: 45,
         key.length: 23,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>required</syntaxtype.keyword> <syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.conforms: [
@@ -722,7 +710,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "x",
             key.name: "x",
-            key.offset: 90,
+            key.offset: 64,
             key.length: 3
           }
         ]
@@ -732,7 +720,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.name: "init()",
         key.usr: "s:5cake19InitProtoPAAExycfc::SYNTHESIZED::s:5cake113InitClassImplC",
         key.original_usr: "s:5cake19InitProtoPAAExycfc",
-        key.offset: 100,
+        key.offset: 74,
         key.length: 18,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>convenience</syntaxtype.keyword> <syntaxtype.keyword>init</syntaxtype.keyword>()</decl.function.constructor>"
       }
@@ -742,7 +730,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
     key.kind: source.lang.swift.decl.protocol,
     key.name: "InitProto",
     key.usr: "s:5cake19InitProtoP",
-    key.offset: 122,
+    key.offset: 96,
     key.length: 42,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>InitProto</decl.name></decl.protocol>",
     key.entities: [
@@ -750,7 +738,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(x:)",
         key.usr: "s:5cake19InitProtoP1xxSi_tcfc",
-        key.offset: 148,
+        key.offset: 122,
         key.length: 14,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.entities: [
@@ -758,7 +746,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "x",
             key.name: "x",
-            key.offset: 158,
+            key.offset: 132,
             key.length: 3
           }
         ]
@@ -767,7 +755,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
   },
   {
     key.kind: source.lang.swift.decl.extension.protocol,
-    key.offset: 166,
+    key.offset: 140,
     key.length: 35,
     key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:5cake19InitProtoP\">InitProto</ref.protocol></decl.name></decl.extension.protocol>",
     key.extends: {
@@ -780,7 +768,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init()",
         key.usr: "s:5cake19InitProtoPAAExycfc",
-        key.offset: 193,
+        key.offset: 167,
         key.length: 6,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>()</decl.function.constructor>"
       }
@@ -790,7 +778,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
     key.kind: source.lang.swift.decl.struct,
     key.name: "InitStructImpl",
     key.usr: "s:5cake114InitStructImplV",
-    key.offset: 203,
+    key.offset: 177,
     key.length: 75,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>InitStructImpl</decl.name> : <ref.protocol usr=\"s:5cake19InitProtoP\">InitProto</ref.protocol></decl.struct>",
     key.conforms: [
@@ -805,7 +793,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.constructor,
         key.name: "init(x:)",
         key.usr: "s:5cake114InitStructImplV1xACSi_tcfc",
-        key.offset: 250,
+        key.offset: 224,
         key.length: 14,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.constructor>",
         key.conforms: [
@@ -820,7 +808,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "x",
             key.name: "x",
-            key.offset: 260,
+            key.offset: 234,
             key.length: 3
           }
         ]
@@ -830,7 +818,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.name: "init()",
         key.usr: "s:5cake19InitProtoPAAExycfc::SYNTHESIZED::s:5cake114InitStructImplV",
         key.original_usr: "s:5cake19InitProtoPAAExycfc",
-        key.offset: 270,
+        key.offset: 244,
         key.length: 6,
         key.fully_annotated_decl: "<decl.function.constructor><syntaxtype.keyword>init</syntaxtype.keyword>()</decl.function.constructor>"
       }
@@ -840,7 +828,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P1",
     key.usr: "s:5cake12P1P",
-    key.offset: 280,
+    key.offset: 254,
     key.length: 167,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P1</decl.name></decl.protocol>",
     key.entities: [
@@ -848,7 +836,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo1()",
         key.usr: "s:5cake12P1P4foo1yyF",
-        key.offset: 299,
+        key.offset: 273,
         key.length: 11,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo1</decl.name>()</decl.function.method.instance>"
       },
@@ -856,7 +844,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.var.instance,
         key.name: "Ins",
         key.usr: "s:5cake12P1P3InsSivp",
-        key.offset: 316,
+        key.offset: 290,
         key.length: 24,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>Ins</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -864,7 +852,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo2(a:b:)",
         key.usr: "s:5cake12P1P4foo21a1bySi_SitF",
-        key.offset: 346,
+        key.offset: 320,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo2</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>a</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>b</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -872,14 +860,14 @@ extension Dictionary.Keys where Key : cake1.P1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "a",
             key.name: "a",
-            key.offset: 361,
+            key.offset: 335,
             key.length: 3
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "b",
             key.name: "b",
-            key.offset: 371,
+            key.offset: 345,
             key.length: 3
           }
         ]
@@ -888,7 +876,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.subscript,
         key.name: "subscript(_:)",
         key.usr: "s:5cake12P1PyS2icip",
-        key.offset: 381,
+        key.offset: 355,
         key.length: 38,
         key.fully_annotated_decl: "<decl.function.subscript><syntaxtype.keyword>subscript</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.name>a</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Si\">Int</ref.struct></decl.function.returntype> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.function.subscript>",
         key.entities: [
@@ -896,7 +884,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "a",
-            key.offset: 396,
+            key.offset: 370,
             key.length: 3
           }
         ]
@@ -905,7 +893,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fooConstraint()",
         key.usr: "s:5cake12P1P13fooConstraintyyF",
-        key.offset: 425,
+        key.offset: 399,
         key.length: 20,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooConstraint</decl.name>()</decl.function.method.instance>"
       }
@@ -915,7 +903,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P2",
     key.usr: "s:5cake12P2P",
-    key.offset: 449,
+    key.offset: 423,
     key.length: 60,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P2</decl.name> : <ref.protocol usr=\"s:5cake12P1P\">P1</ref.protocol></decl.protocol>",
     key.conforms: [
@@ -930,7 +918,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "bar1()",
         key.usr: "s:5cake12P2P4bar1yyF",
-        key.offset: 479,
+        key.offset: 453,
         key.length: 11,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>bar1</decl.name>()</decl.function.method.instance>"
       },
@@ -938,7 +926,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "bar2()",
         key.usr: "s:5cake12P2P4bar2yyF",
-        key.offset: 496,
+        key.offset: 470,
         key.length: 11,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>bar2</decl.name>()</decl.function.method.instance>"
       }
@@ -946,7 +934,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
   },
   {
     key.kind: source.lang.swift.decl.extension.protocol,
-    key.offset: 511,
+    key.offset: 485,
     key.length: 118,
     key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:5cake12P2P\">P2</ref.protocol></decl.name></decl.extension.protocol>",
     key.extends: {
@@ -960,7 +948,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.name: "foo1()",
         key.usr: "s:5cake12P2PAAE4foo1yyF",
         key.default_implementation_of: "s:5cake12P1P4foo1yyF",
-        key.offset: 531,
+        key.offset: 505,
         key.length: 11,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo1</decl.name>()</decl.function.method.instance>"
       },
@@ -969,7 +957,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.name: "Ins",
         key.usr: "s:5cake12P2PAAE3InsSivp",
         key.default_implementation_of: "s:5cake12P1P3InsSivp",
-        key.offset: 548,
+        key.offset: 522,
         key.length: 12,
         key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>Ins</decl.name>: <decl.var.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.var.instance>"
       },
@@ -978,7 +966,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.name: "foo2(a:b:)",
         key.usr: "s:5cake12P2PAAE4foo21a1bySi_SitF",
         key.default_implementation_of: "s:5cake12P1P4foo21a1bySi_SitF",
-        key.offset: 566,
+        key.offset: 540,
         key.length: 29,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo2</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>a</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>b</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -986,14 +974,14 @@ extension Dictionary.Keys where Key : cake1.P1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "a",
             key.name: "a",
-            key.offset: 581,
+            key.offset: 555,
             key.length: 3
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "b",
             key.name: "b",
-            key.offset: 591,
+            key.offset: 565,
             key.length: 3
           }
         ]
@@ -1003,7 +991,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.name: "subscript(_:)",
         key.usr: "s:5cake12P2PAAEyS2icip",
         key.default_implementation_of: "s:5cake12P1PyS2icip",
-        key.offset: 601,
+        key.offset: 575,
         key.length: 26,
         key.fully_annotated_decl: "<decl.function.subscript><syntaxtype.keyword>subscript</syntaxtype.keyword>(<decl.var.parameter><decl.var.parameter.name>a</decl.var.parameter.name>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr=\"s:Si\">Int</ref.struct></decl.function.returntype> { <syntaxtype.keyword>get</syntaxtype.keyword> <syntaxtype.keyword>set</syntaxtype.keyword> }</decl.function.subscript>",
         key.entities: [
@@ -1011,7 +999,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "_",
             key.name: "a",
-            key.offset: 616,
+            key.offset: 590,
             key.length: 3
           }
         ]
@@ -1025,7 +1013,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.description: "Self : P3"
       }
     ],
-    key.offset: 631,
+    key.offset: 605,
     key.length: 64,
     key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:5cake12P2P\">P2</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:5cake12P2P4Selfxmfp\">Self</ref.generic_type_param> : <ref.protocol usr=\"s:5cake12P3P\">P3</ref.protocol></decl.generic_type_requirement></decl.extension.protocol>",
     key.extends: {
@@ -1039,7 +1027,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.name: "fooConstraint()",
         key.usr: "s:5cake12P2PA2A2P3RzrlE13fooConstraintyyF",
         key.default_implementation_of: "s:5cake12P1P13fooConstraintyyF",
-        key.offset: 673,
+        key.offset: 647,
         key.length: 20,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooConstraint</decl.name>()</decl.function.method.instance>"
       }
@@ -1049,7 +1037,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P3",
     key.usr: "s:5cake12P3P",
-    key.offset: 697,
+    key.offset: 671,
     key.length: 38,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P3</decl.name></decl.protocol>",
     key.entities: [
@@ -1057,7 +1045,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "p3Required()",
         key.usr: "s:5cake12P3P10p3RequiredyyF",
-        key.offset: 716,
+        key.offset: 690,
         key.length: 17,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>p3Required</decl.name>()</decl.function.method.instance>"
       }
@@ -1078,7 +1066,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.description: "Key : Hashable"
       }
     ],
-    key.offset: 737,
+    key.offset: 711,
     key.length: 45,
     key.fully_annotated_decl: "<decl.extension.struct><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.struct usr=\"s:SD\">Dictionary</ref.struct>.<ref.struct usr=\"s:SD4KeysV\">Keys</ref.struct></decl.name></decl.extension.struct>",
     key.extends: {
@@ -1091,7 +1079,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo()",
         key.usr: "s:SD4KeysV5cake1E3fooyyF",
-        key.offset: 770,
+        key.offset: 744,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo</decl.name>()</decl.function.method.instance>"
       }
@@ -1115,7 +1103,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.description: "Key : P1"
       }
     ],
-    key.offset: 784,
+    key.offset: 758,
     key.length: 66,
     key.fully_annotated_decl: "<decl.extension.struct><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.struct usr=\"s:SD\">Dictionary</ref.struct>.<ref.struct usr=\"s:SD4KeysV\">Keys</ref.struct></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:SD3Keyxmfp\">Key</ref.generic_type_param> : <ref.protocol usr=\"s:5cake12P1P\">P1</ref.protocol></decl.generic_type_requirement></decl.extension.struct>",
     key.extends: {
@@ -1128,7 +1116,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "bar()",
         key.usr: "s:SD4KeysV5cake1AC2P1RzrlE3baryyF",
-        key.offset: 838,
+        key.offset: 812,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>bar</decl.name>()</decl.function.method.instance>"
       }
diff --git a/test/SourceKit/DocSupport/doc_swift_module_availability_maccatalyst_is_deprecated.swift b/test/SourceKit/DocSupport/doc_swift_module_availability_maccatalyst_is_deprecated.swift
index 244a47dda87c0..bc632b8104751 100644
--- a/test/SourceKit/DocSupport/doc_swift_module_availability_maccatalyst_is_deprecated.swift
+++ b/test/SourceKit/DocSupport/doc_swift_module_availability_maccatalyst_is_deprecated.swift
@@ -4,7 +4,7 @@
 // RUN: %swift -emit-module -target %target-cpu-apple-ios13.1-macabi -o %t.mod/availability.swiftmodule %s -parse-as-library -emit-module-doc-path %t.mod/availability.swiftdoc
 // RUN: %sourcekitd-test -req=doc-info -module availability -- -target %target-cpu-apple-ios13.1-macabi -I %t.mod | %FileCheck %s
 
-@available(macCatalyst, deprecated: 20.0)
+@available(macCatalyst, deprecated: 50.0)
 public func deprecatedInFutureVersion_catalyst() {}
 // CHECK-LABEL: key.name: "deprecatedInFutureVersion_catalyst()"
 // CHECK-NOT: {
@@ -12,12 +12,12 @@ public func deprecatedInFutureVersion_catalyst() {}
 // CHECK-NEXT:     {
 // CHECK-NEXT:       key.kind: source.lang.swift.attribute.availability,
 // CHECK-NEXT:       key.platform: source.availability.platform.maccatalyst,
-// CHECK-NEXT:       key.deprecated: "20.0"
+// CHECK-NEXT:       key.deprecated: "50.0"
 // CHECK-NEXT:     }
 // CHECK-NEXT:   ]
 // CHECK-NEXT: }
 
-@available(iOS, deprecated: 20.0)
+@available(iOS, deprecated: 50.0)
 public func deprecatedInFutureVersion_iOS() {}
 // CHECK-LABEL: key.name: "deprecatedInFutureVersion_iOS()"
 // CHECK-NOT: {
@@ -25,7 +25,7 @@ public func deprecatedInFutureVersion_iOS() {}
 // CHECK-NEXT:     {
 // CHECK-NEXT:       key.kind: source.lang.swift.attribute.availability,
 // CHECK-NEXT:       key.platform: source.availability.platform.ios,
-// CHECK-NEXT:       key.deprecated: "20.0"
+// CHECK-NEXT:       key.deprecated: "50.0"
 // CHECK-NEXT:     }
 // CHECK-NEXT:   ]
 // CHECK-NEXT: }
diff --git a/test/SourceKit/DocSupport/doc_swift_module_class_extension.swift.response b/test/SourceKit/DocSupport/doc_swift_module_class_extension.swift.response
index add34c8e2d52e..b7e0a30aa9daf 100644
--- a/test/SourceKit/DocSupport/doc_swift_module_class_extension.swift.response
+++ b/test/SourceKit/DocSupport/doc_swift_module_class_extension.swift.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 class C<T> {
 }
 
@@ -52,371 +50,361 @@ extension P8 where Self.T : module_with_class_extension.E {
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
     key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 26,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 32,
+    key.offset: 6,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 34,
+    key.offset: 8,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 42,
+    key.offset: 16,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.class,
     key.name: "C",
     key.usr: "s:27module_with_class_extension1CC",
-    key.offset: 52,
+    key.offset: 26,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 56,
+    key.offset: 30,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "P8",
     key.usr: "s:27module_with_class_extension2P8P",
-    key.offset: 84,
+    key.offset: 58,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 92,
+    key.offset: 66,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.class,
     key.name: "C",
     key.usr: "s:27module_with_class_extension1CC",
-    key.offset: 102,
+    key.offset: 76,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 104,
+    key.offset: 78,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "T",
     key.usr: "s:27module_with_class_extension1CC1Txmfp",
-    key.offset: 110,
+    key.offset: 84,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 114,
+    key.offset: 88,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.ref.class,
     key.name: "D",
     key.usr: "s:27module_with_class_extension1DC",
-    key.offset: 142,
+    key.offset: 116,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 151,
+    key.offset: 125,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 156,
+    key.offset: 130,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 167,
+    key.offset: 141,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 172,
+    key.offset: 146,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 181,
+    key.offset: 155,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.class,
     key.name: "C",
     key.usr: "s:27module_with_class_extension1CC",
-    key.offset: 191,
+    key.offset: 165,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 193,
+    key.offset: 167,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "T",
     key.usr: "s:27module_with_class_extension1CC1Txmfp",
-    key.offset: 199,
+    key.offset: 173,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 203,
+    key.offset: 177,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.ref.class,
     key.name: "E",
     key.usr: "s:27module_with_class_extension1EC",
-    key.offset: 231,
+    key.offset: 205,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 240,
+    key.offset: 214,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 245,
+    key.offset: 219,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 254,
+    key.offset: 228,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 260,
+    key.offset: 234,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 267,
+    key.offset: 241,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 273,
+    key.offset: 247,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 280,
+    key.offset: 254,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 286,
+    key.offset: 260,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 288,
+    key.offset: 262,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 291,
+    key.offset: 265,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "T",
     key.usr: "s:27module_with_class_extension1FC1Txmfp",
-    key.offset: 297,
+    key.offset: 271,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 301,
+    key.offset: 275,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.ref.class,
     key.name: "D",
     key.usr: "s:27module_with_class_extension1DC",
-    key.offset: 329,
+    key.offset: 303,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 338,
+    key.offset: 312,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 343,
+    key.offset: 317,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 352,
+    key.offset: 326,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.class,
     key.name: "F",
     key.usr: "s:27module_with_class_extension1FC",
-    key.offset: 362,
+    key.offset: 336,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 366,
+    key.offset: 340,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "P8",
     key.usr: "s:27module_with_class_extension2P8P",
-    key.offset: 394,
+    key.offset: 368,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 402,
+    key.offset: 376,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 411,
+    key.offset: 385,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 421,
+    key.offset: 395,
     key.length: 14
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 436,
+    key.offset: 410,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 441,
+    key.offset: 415,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "P8",
     key.usr: "s:27module_with_class_extension2P8P",
-    key.offset: 451,
+    key.offset: 425,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 454,
+    key.offset: 428,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "Self",
     key.usr: "s:27module_with_class_extension2P8P4Selfxmfp",
-    key.offset: 460,
+    key.offset: 434,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.ref.associatedtype,
     key.name: "T",
     key.usr: "s:27module_with_class_extension2P8P1TQa",
-    key.offset: 465,
+    key.offset: 439,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 469,
+    key.offset: 443,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.ref.class,
     key.name: "D",
     key.usr: "s:27module_with_class_extension1DC",
-    key.offset: 497,
+    key.offset: 471,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 506,
+    key.offset: 480,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 511,
+    key.offset: 485,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 520,
+    key.offset: 494,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.protocol,
     key.name: "P8",
     key.usr: "s:27module_with_class_extension2P8P",
-    key.offset: 530,
+    key.offset: 504,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 533,
+    key.offset: 507,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "Self",
     key.usr: "s:27module_with_class_extension2P8P4Selfxmfp",
-    key.offset: 539,
+    key.offset: 513,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.ref.associatedtype,
     key.name: "T",
     key.usr: "s:27module_with_class_extension2P8P1TQa",
-    key.offset: 544,
+    key.offset: 518,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 548,
+    key.offset: 522,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.ref.class,
     key.name: "E",
     key.usr: "s:27module_with_class_extension1EC",
-    key.offset: 576,
+    key.offset: 550,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 585,
+    key.offset: 559,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 590,
+    key.offset: 564,
     key.length: 3
   }
 ]
@@ -430,7 +418,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.name: "T"
       }
     ],
-    key.offset: 26,
+    key.offset: 0,
     key.length: 14,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>C</decl.name>&lt;<decl.generic_type_param usr=\"s:27module_with_class_extension1CC1Txmfp\"><decl.generic_type_param.name>T</decl.generic_type_param.name></decl.generic_type_param>&gt;</decl.class>"
   },
@@ -441,7 +429,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.name: "T"
       }
     ],
-    key.offset: 42,
+    key.offset: 16,
     key.length: 48,
     key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"s:27module_with_class_extension1CC\">C</ref.class></decl.name> : <ref.protocol usr=\"s:27module_with_class_extension2P8P\">P8</ref.protocol></decl.extension.class>",
     key.conforms: [
@@ -469,7 +457,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.description: "T : D"
       }
     ],
-    key.offset: 92,
+    key.offset: 66,
     key.length: 87,
     key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"s:27module_with_class_extension1CC\">C</ref.class></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension1CC1Txmfp\">T</ref.generic_type_param> : <ref.class usr=\"s:27module_with_class_extension1DC\">D</ref.class></decl.generic_type_requirement></decl.extension.class>",
     key.extends: {
@@ -482,7 +470,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "foo()",
         key.usr: "s:27module_with_class_extension1CCA2A1DCRbzlE3fooyyF",
-        key.offset: 151,
+        key.offset: 125,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo</decl.name>()</decl.function.method.instance>"
       },
@@ -491,7 +479,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.name: "bar()",
         key.usr: "s:27module_with_class_extension2P8PA2A1DC1TRczrlE3baryyF::SYNTHESIZED::s:27module_with_class_extension1CC",
         key.original_usr: "s:27module_with_class_extension2P8PA2A1DC1TRczrlE3baryyF",
-        key.offset: 167,
+        key.offset: 141,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>bar</decl.name>()</decl.function.method.instance>"
       }
@@ -504,7 +492,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.description: "T : E"
       }
     ],
-    key.offset: 181,
+    key.offset: 155,
     key.length: 71,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.class usr=\"s:27module_with_class_extension1CC\">C</ref.class> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension1CC1Txmfp\">T</ref.generic_type_param> : <ref.class usr=\"s:27module_with_class_extension1EC\">E</ref.class></decl.generic_type_requirement>",
     key.extends: {
@@ -518,7 +506,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.name: "baz()",
         key.usr: "s:27module_with_class_extension2P8PA2A1EC1TRczrlE3bazyyF::SYNTHESIZED::s:27module_with_class_extension1CC",
         key.original_usr: "s:27module_with_class_extension2P8PA2A1EC1TRczrlE3bazyyF",
-        key.offset: 240,
+        key.offset: 214,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>baz</decl.name>()</decl.function.method.instance>"
       }
@@ -528,7 +516,7 @@ extension P8 where Self.T : module_with_class_extension.E {
     key.kind: source.lang.swift.decl.class,
     key.name: "D",
     key.usr: "s:27module_with_class_extension1DC",
-    key.offset: 254,
+    key.offset: 228,
     key.length: 11,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>D</decl.name></decl.class>"
   },
@@ -536,7 +524,7 @@ extension P8 where Self.T : module_with_class_extension.E {
     key.kind: source.lang.swift.decl.class,
     key.name: "E",
     key.usr: "s:27module_with_class_extension1EC",
-    key.offset: 267,
+    key.offset: 241,
     key.length: 11,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>E</decl.name></decl.class>"
   },
@@ -554,7 +542,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.description: "T : D"
       }
     ],
-    key.offset: 280,
+    key.offset: 254,
     key.length: 70,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>F</decl.name>&lt;<decl.generic_type_param usr=\"s:27module_with_class_extension1FC1Txmfp\"><decl.generic_type_param.name>T</decl.generic_type_param.name></decl.generic_type_param>&gt; <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension1FC1Txmfp\">T</ref.generic_type_param> : <ref.class usr=\"s:27module_with_class_extension1DC\">D</ref.class></decl.generic_type_requirement></decl.class>",
     key.entities: [
@@ -563,7 +551,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.name: "bar()",
         key.usr: "s:27module_with_class_extension2P8PA2A1DC1TRczrlE3baryyF::SYNTHESIZED::s:27module_with_class_extension1FC",
         key.original_usr: "s:27module_with_class_extension2P8PA2A1DC1TRczrlE3baryyF",
-        key.offset: 338,
+        key.offset: 312,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>bar</decl.name>()</decl.function.method.instance>"
       }
@@ -581,7 +569,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.description: "T : D"
       }
     ],
-    key.offset: 352,
+    key.offset: 326,
     key.length: 48,
     key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"s:27module_with_class_extension1FC\">F</ref.class></decl.name> : <ref.protocol usr=\"s:27module_with_class_extension2P8P\">P8</ref.protocol></decl.extension.class>",
     key.conforms: [
@@ -601,7 +589,7 @@ extension P8 where Self.T : module_with_class_extension.E {
     key.kind: source.lang.swift.decl.protocol,
     key.name: "P8",
     key.usr: "s:27module_with_class_extension2P8P",
-    key.offset: 402,
+    key.offset: 376,
     key.length: 37,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>P8</decl.name></decl.protocol>",
     key.entities: [
@@ -609,7 +597,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.kind: source.lang.swift.decl.associatedtype,
         key.name: "T",
         key.usr: "s:27module_with_class_extension2P8P1TQa",
-        key.offset: 421,
+        key.offset: 395,
         key.length: 16,
         key.fully_annotated_decl: "<decl.associatedtype><syntaxtype.keyword>associatedtype</syntaxtype.keyword> <decl.name>T</decl.name></decl.associatedtype>"
       }
@@ -622,7 +610,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.description: "Self.T : D"
       }
     ],
-    key.offset: 441,
+    key.offset: 415,
     key.length: 77,
     key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:27module_with_class_extension2P8P\">P8</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension2P8P4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:27module_with_class_extension2P8P1TQa\">T</ref.associatedtype> : <ref.class usr=\"s:27module_with_class_extension1DC\">D</ref.class></decl.generic_type_requirement></decl.extension.protocol>",
     key.extends: {
@@ -635,7 +623,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "bar()",
         key.usr: "s:27module_with_class_extension2P8PA2A1DC1TRczrlE3baryyF",
-        key.offset: 506,
+        key.offset: 480,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>bar</decl.name>()</decl.function.method.instance>"
       }
@@ -648,7 +636,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.description: "Self.T : E"
       }
     ],
-    key.offset: 520,
+    key.offset: 494,
     key.length: 77,
     key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:27module_with_class_extension2P8P\">P8</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension2P8P4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:27module_with_class_extension2P8P1TQa\">T</ref.associatedtype> : <ref.class usr=\"s:27module_with_class_extension1EC\">E</ref.class></decl.generic_type_requirement></decl.extension.protocol>",
     key.extends: {
@@ -661,7 +649,7 @@ extension P8 where Self.T : module_with_class_extension.E {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "baz()",
         key.usr: "s:27module_with_class_extension2P8PA2A1EC1TRczrlE3bazyyF",
-        key.offset: 585,
+        key.offset: 559,
         key.length: 10,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>baz</decl.name>()</decl.function.method.instance>"
       }
diff --git a/test/SourceKit/DocSupport/doc_swift_module_cross_import.swift.A.response b/test/SourceKit/DocSupport/doc_swift_module_cross_import.swift.A.response
index 7e9d1ec0efb5c..3be4f1b146ff2 100644
--- a/test/SourceKit/DocSupport/doc_swift_module_cross_import.swift.A.response
+++ b/test/SourceKit/DocSupport/doc_swift_module_cross_import.swift.A.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 func fromA()
 
 
@@ -30,143 +28,133 @@ func other(x x: A.From_ABAdditionsType)
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
     key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 26,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 31,
+    key.offset: 5,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 41,
+    key.offset: 15,
     key.length: 23
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 44,
+    key.offset: 18,
     key.length: 19
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 65,
+    key.offset: 39,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 72,
+    key.offset: 46,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 75,
+    key.offset: 49,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 114,
+    key.offset: 88,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 121,
+    key.offset: 95,
     key.length: 20
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 147,
+    key.offset: 121,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 186,
+    key.offset: 160,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 191,
+    key.offset: 165,
     key.length: 16
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 212,
+    key.offset: 186,
     key.length: 29
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 215,
+    key.offset: 189,
     key.length: 25
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 242,
+    key.offset: 216,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 249,
+    key.offset: 223,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 252,
+    key.offset: 226,
     key.length: 46
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 298,
+    key.offset: 272,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 303,
+    key.offset: 277,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 334,
+    key.offset: 308,
     key.length: 46
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 380,
+    key.offset: 354,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 385,
+    key.offset: 359,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 391,
+    key.offset: 365,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 393,
+    key.offset: 367,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 396,
+    key.offset: 370,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "From_ABAdditionsType",
     key.usr: "s:12_ABAdditions05From_A4TypeV",
-    key.offset: 398,
+    key.offset: 372,
     key.length: 20
   }
 ]
@@ -175,7 +163,7 @@ func other(x x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fromA()",
     key.usr: "s:1A5fromAyyF",
-    key.offset: 26,
+    key.offset: 0,
     key.length: 12,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromA</decl.name>()</decl.function.free>"
   },
@@ -183,7 +171,7 @@ func other(x x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.struct,
     key.name: "From_ABAdditionsType",
     key.usr: "s:12_ABAdditions05From_A4TypeV",
-    key.offset: 114,
+    key.offset: 88,
     key.length: 31,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>From_ABAdditionsType</decl.name></decl.struct>",
     key.required_bystanders: [
@@ -194,7 +182,7 @@ func other(x x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.function.free,
     key.name: "from_ABAdditions()",
     key.usr: "s:12_ABAdditions05from_A0yyF",
-    key.offset: 186,
+    key.offset: 160,
     key.length: 23,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>from_ABAdditions</decl.name>()</decl.function.free>",
     key.required_bystanders: [
@@ -205,7 +193,7 @@ func other(x x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.function.free,
     key.name: "from__ABAdditionsCAdditions()",
     key.usr: "s:23__ABAdditionsCAdditions06from__aB0yyF",
-    key.offset: 298,
+    key.offset: 272,
     key.length: 34,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>from__ABAdditionsCAdditions</decl.name>()</decl.function.free>",
     key.required_bystanders: [
@@ -217,7 +205,7 @@ func other(x x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.function.free,
     key.name: "other(x:)",
     key.usr: "s:23__ABAdditionsCAdditions5other1xy01_A005From_A4TypeV_tF",
-    key.offset: 380,
+    key.offset: 354,
     key.length: 39,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>other</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:12_ABAdditions05From_A4TypeV\">From_ABAdditionsType</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.free>",
     key.entities: [
@@ -225,7 +213,7 @@ func other(x x: A.From_ABAdditionsType)
         key.kind: source.lang.swift.decl.var.local,
         key.keyword: "x",
         key.name: "x",
-        key.offset: 396,
+        key.offset: 370,
         key.length: 22
       }
     ],
diff --git a/test/SourceKit/DocSupport/doc_swift_module_cross_import.swift.Other.response b/test/SourceKit/DocSupport/doc_swift_module_cross_import.swift.Other.response
index 7620ca1c322e0..5299b1ba6ca33 100644
--- a/test/SourceKit/DocSupport/doc_swift_module_cross_import.swift.Other.response
+++ b/test/SourceKit/DocSupport/doc_swift_module_cross_import.swift.Other.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 func fromOther()
 
 
@@ -7,7 +5,6 @@ func fromOther()
 
 import B
 import C
-import A
 
 // Available when C is imported with Other
 func filtered()
@@ -20,91 +17,71 @@ func from_OtherCAdditions()
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
     key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 26,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 31,
+    key.offset: 5,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 45,
+    key.offset: 19,
     key.length: 23
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 48,
+    key.offset: 22,
     key.length: 19
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 69,
+    key.offset: 43,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 76,
+    key.offset: 50,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 78,
+    key.offset: 52,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 85,
-    key.length: 1
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 87,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 94,
+    key.offset: 59,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 97,
+    key.offset: 62,
     key.length: 43
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 140,
+    key.offset: 105,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 145,
+    key.offset: 110,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 157,
+    key.offset: 122,
     key.length: 43
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 200,
+    key.offset: 165,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 205,
+    key.offset: 170,
     key.length: 20
   }
 ]
@@ -113,7 +90,7 @@ func from_OtherCAdditions()
     key.kind: source.lang.swift.decl.function.free,
     key.name: "fromOther()",
     key.usr: "s:5Other04fromA0yyF",
-    key.offset: 26,
+    key.offset: 0,
     key.length: 16,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromOther</decl.name>()</decl.function.free>"
   },
@@ -121,7 +98,7 @@ func from_OtherCAdditions()
     key.kind: source.lang.swift.decl.function.free,
     key.name: "filtered()",
     key.usr: "s:16_OtherCAdditions8filteredyyF",
-    key.offset: 140,
+    key.offset: 105,
     key.length: 15,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>filtered</decl.name>()</decl.function.free>",
     key.attributes: [
@@ -140,7 +117,7 @@ func from_OtherCAdditions()
     key.name: "from_OtherCAdditions()",
     key.usr: "s:16_OtherCAdditions05from_aB0yyF",
     key.doc.full_as_xml: "<Function><Name>from_OtherCAdditions()</Name><USR>s:16_OtherCAdditions05from_aB0yyF</USR><Declaration>func from_OtherCAdditions()</Declaration><CommentParts><Abstract><Para>This has some interesting documentation that shouldn’t be separated from the decl when we print the comment detailing its required bystanders in the generated interface of ‘Other’.</Para></Abstract></CommentParts></Function>",
-    key.offset: 200,
+    key.offset: 165,
     key.length: 27,
     key.fully_annotated_decl: "<decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>from_OtherCAdditions</decl.name>()</decl.function.free>",
     key.required_bystanders: [
diff --git a/test/SourceKit/DocSupport/doc_system_module_underscored.swift.response b/test/SourceKit/DocSupport/doc_system_module_underscored.swift.response
index 59246b35fda05..56f9041c160a8 100644
--- a/test/SourceKit/DocSupport/doc_system_module_underscored.swift.response
+++ b/test/SourceKit/DocSupport/doc_system_module_underscored.swift.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 struct A<T> {
 
     func fromA(takesT takesT: T)
@@ -96,872 +94,862 @@ protocol Other1 {
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
     key.offset: 7,
-    key.length: 17
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 26,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 33,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 35,
+    key.offset: 9,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 45,
+    key.offset: 19,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 50,
+    key.offset: 24,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 56,
+    key.offset: 30,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 63,
+    key.offset: 37,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "T",
     key.usr: "s:16UnderscoredProto1AV1Txmfp",
-    key.offset: 71,
+    key.offset: 45,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 79,
+    key.offset: 53,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 84,
+    key.offset: 58,
     key.length: 14
   },
   {
     key.kind: source.lang.swift.syntaxtype.argument,
-    key.offset: 99,
+    key.offset: 73,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.parameter,
-    key.offset: 106,
+    key.offset: 80,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "T",
     key.usr: "s:16UnderscoredProto1AV1Txmfp",
-    key.offset: 114,
+    key.offset: 88,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 122,
+    key.offset: 96,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 127,
+    key.offset: 101,
     key.length: 18
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 151,
+    key.offset: 125,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "A",
     key.usr: "s:16UnderscoredProto1AV",
-    key.offset: 161,
+    key.offset: 135,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 170,
+    key.offset: 144,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 175,
+    key.offset: 149,
     key.length: 28
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 209,
+    key.offset: 183,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "A",
     key.usr: "s:16UnderscoredProto1AV",
-    key.offset: 219,
+    key.offset: 193,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 221,
+    key.offset: 195,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "T",
     key.usr: "s:16UnderscoredProto1AV1Txmfp",
-    key.offset: 227,
+    key.offset: 201,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.operator,
-    key.offset: 229,
+    key.offset: 203,
     key.length: 2
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "String",
     key.usr: "s:SS",
-    key.offset: 232,
+    key.offset: 206,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 246,
+    key.offset: 220,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 256,
+    key.offset: 230,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.ref.struct,
     key.name: "Int",
     key.usr: "s:Si",
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     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 1600,
+    key.offset: 1574,
     key.length: 6
   }
 ]
@@ -975,7 +963,7 @@ protocol Other1 {
         key.name: "T"
       }
     ],
-    key.offset: 26,
+    key.offset: 0,
     key.length: 123,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>A</decl.name>&lt;<decl.generic_type_param usr=\"s:16UnderscoredProto1AV1Txmfp\"><decl.generic_type_param.name>T</decl.generic_type_param.name></decl.generic_type_param>&gt;</decl.struct>",
     key.entities: [
@@ -983,7 +971,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fromA(takesT:)",
         key.usr: "s:16UnderscoredProto1AV5fromA6takesTyx_tF",
-        key.offset: 45,
+        key.offset: 19,
         key.length: 28,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromA</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesT</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1AV1Txmfp\">T</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -991,7 +979,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesT",
             key.name: "takesT",
-            key.offset: 71,
+            key.offset: 45,
             key.length: 1
           }
         ]
@@ -1000,7 +988,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fromAExtension(takesT:)",
         key.usr: "s:16UnderscoredProto1AV14fromAExtension6takesTyx_tF",
-        key.offset: 79,
+        key.offset: 53,
         key.length: 37,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromAExtension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesT</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1AV1Txmfp\">T</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1008,7 +996,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesT",
             key.name: "takesT",
-            key.offset: 114,
+            key.offset: 88,
             key.length: 1
           }
         ]
@@ -1018,7 +1006,7 @@ protocol Other1 {
         key.name: "fromProtoExtension()",
         key.usr: "s:16UnderscoredProto01_aB0PAAE04fromB9ExtensionyyF::SYNTHESIZED::s:16UnderscoredProto1AV",
         key.original_usr: "s:16UnderscoredProto01_aB0PAAE04fromB9ExtensionyyF",
-        key.offset: 122,
+        key.offset: 96,
         key.length: 25,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromProtoExtension</decl.name>()</decl.function.method.instance>"
       }
@@ -1026,7 +1014,7 @@ protocol Other1 {
   },
   {
     key.kind: source.lang.swift.decl.extension.struct,
-    key.offset: 151,
+    key.offset: 125,
     key.length: 56,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"s:16UnderscoredProto1AV\">A</ref.struct>",
     key.extends: {
@@ -1040,7 +1028,7 @@ protocol Other1 {
         key.name: "fromDeprecatedProtoExtension()",
         key.usr: "s:16UnderscoredProto01_aB0PAAE014fromDeprecatedB9ExtensionyyF::SYNTHESIZED::s:16UnderscoredProto1AV",
         key.original_usr: "s:16UnderscoredProto01_aB0PAAE014fromDeprecatedB9ExtensionyyF",
-        key.offset: 170,
+        key.offset: 144,
         key.length: 35,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromDeprecatedProtoExtension</decl.name>()</decl.function.method.instance>"
       }
@@ -1065,7 +1053,7 @@ protocol Other1 {
         key.description: "T == String"
       }
     ],
-    key.offset: 209,
+    key.offset: 183,
     key.length: 185,
     key.fully_annotated_decl: "<decl.extension.struct><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.struct usr=\"s:16UnderscoredProto1AV\">A</ref.struct></decl.name> : <ref.protocol usr=\"s:16UnderscoredProto01_A6Proto2P\">_UnderscoredProto2</ref.protocol> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1AV1Txmfp\">T</ref.generic_type_param> == <ref.struct usr=\"s:SS\">String</ref.struct></decl.generic_type_requirement></decl.extension.struct>",
     key.conforms: [
@@ -1085,7 +1073,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.typealias,
         key.name: "Elem",
         key.usr: "s:16UnderscoredProto1AVAASSRszlE4Elema",
-        key.offset: 246,
+        key.offset: 220,
         key.length: 20,
         key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <decl.name>Elem</decl.name> = <ref.struct usr=\"s:Si\">Int</ref.struct></decl.typealias>",
         key.conforms: [
@@ -1110,7 +1098,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fromAConditionalExtension(takesTIfString:)",
         key.usr: "s:16UnderscoredProto1AVAASSRszlE25fromAConditionalExtension14takesTIfStringySS_tF",
-        key.offset: 272,
+        key.offset: 246,
         key.length: 64,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromAConditionalExtension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesTIfString</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1AVAASSRszlE1Txmfp\">T</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1118,7 +1106,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesTIfString",
             key.name: "takesTIfString",
-            key.offset: 334,
+            key.offset: 308,
             key.length: 1
           }
         ]
@@ -1128,7 +1116,7 @@ protocol Other1 {
         key.name: "fromProto2Extension(takesElem:)",
         key.usr: "s:16UnderscoredProto01_A6Proto2PAAE04fromC9Extension9takesElemy0G0Qz_tF::SYNTHESIZED::s:16UnderscoredProto1AV",
         key.original_usr: "s:16UnderscoredProto01_A6Proto2PAAE04fromC9Extension9takesElemy0G0Qz_tF",
-        key.offset: 342,
+        key.offset: 316,
         key.length: 50,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromProto2Extension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesElem</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1136,7 +1124,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesElem",
             key.name: "takesElem",
-            key.offset: 388,
+            key.offset: 362,
             key.length: 3
           }
         ]
@@ -1155,7 +1143,7 @@ protocol Other1 {
         key.description: "T == String"
       }
     ],
-    key.offset: 396,
+    key.offset: 370,
     key.length: 98,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"s:16UnderscoredProto1AV\">A</ref.struct>",
     key.extends: {
@@ -1169,7 +1157,7 @@ protocol Other1 {
         key.name: "fromDeprecatedConditionalProto2Extension(takesElemInt:)",
         key.usr: "s:16UnderscoredProto01_A6Proto2PAASi4ElemRtzrlE025fromDeprecatedConditionalC9Extension05takesD3IntySi_tF::SYNTHESIZED::s:16UnderscoredProto1AV",
         key.original_usr: "s:16UnderscoredProto01_A6Proto2PAASi4ElemRtzrlE025fromDeprecatedConditionalC9Extension05takesD3IntySi_tF",
-        key.offset: 415,
+        key.offset: 389,
         key.length: 77,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromDeprecatedConditionalProto2Extension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesElemInt</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:Si\">Int</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1177,7 +1165,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesElemInt",
             key.name: "takesElemInt",
-            key.offset: 488,
+            key.offset: 462,
             key.length: 3
           }
         ]
@@ -1200,7 +1188,7 @@ protocol Other1 {
         key.name: "T"
       }
     ],
-    key.offset: 496,
+    key.offset: 470,
     key.length: 253,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>B</decl.name>&lt;<decl.generic_type_param usr=\"s:16UnderscoredProto1BC1Txmfp\"><decl.generic_type_param.name>T</decl.generic_type_param.name></decl.generic_type_param>&gt; : <ref.protocol usr=\"s:16UnderscoredProto01_aB0P\">_UnderscoredProto</ref.protocol></decl.class>",
     key.conforms: [
@@ -1215,7 +1203,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fromB(takesT:)",
         key.usr: "s:16UnderscoredProto1BC5fromB6takesTyx_tF",
-        key.offset: 514,
+        key.offset: 488,
         key.length: 28,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromB</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesT</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1BC1Txmfp\">T</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1223,7 +1211,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesT",
             key.name: "takesT",
-            key.offset: 540,
+            key.offset: 514,
             key.length: 1
           }
         ]
@@ -1232,7 +1220,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.typealias,
         key.name: "Elem",
         key.usr: "s:16UnderscoredProto1BC4Elema",
-        key.offset: 548,
+        key.offset: 522,
         key.length: 23,
         key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <decl.name>Elem</decl.name> = <ref.struct usr=\"s:SS\">String</ref.struct></decl.typealias>"
       },
@@ -1241,7 +1229,7 @@ protocol Other1 {
         key.name: "fromProtoExtension()",
         key.usr: "s:16UnderscoredProto01_aB0PAAE04fromB9ExtensionyyF::SYNTHESIZED::s:16UnderscoredProto1BC",
         key.original_usr: "s:16UnderscoredProto01_aB0PAAE04fromB9ExtensionyyF",
-        key.offset: 577,
+        key.offset: 551,
         key.length: 25,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromProtoExtension</decl.name>()</decl.function.method.instance>"
       },
@@ -1250,7 +1238,7 @@ protocol Other1 {
         key.name: "fromProto2Extension(takesElem:)",
         key.usr: "s:16UnderscoredProto01_A6Proto2PAAE04fromC9Extension9takesElemy0G0Qz_tF::SYNTHESIZED::s:16UnderscoredProto1BC",
         key.original_usr: "s:16UnderscoredProto01_A6Proto2PAAE04fromC9Extension9takesElemy0G0Qz_tF",
-        key.offset: 608,
+        key.offset: 582,
         key.length: 53,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromProto2Extension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesElem</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:SS\">String</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1258,7 +1246,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesElem",
             key.name: "takesElem",
-            key.offset: 654,
+            key.offset: 628,
             key.length: 6
           }
         ]
@@ -1268,7 +1256,7 @@ protocol Other1 {
         key.name: "fromConditionalProto2Extension(takesElemIfString:)",
         key.usr: "s:16UnderscoredProto01_A6Proto2PAASS4ElemRtzrlE015fromConditionalC9Extension05takesD8IfStringySS_tF::SYNTHESIZED::s:16UnderscoredProto1BC",
         key.original_usr: "s:16UnderscoredProto01_A6Proto2PAASS4ElemRtzrlE015fromConditionalC9Extension05takesD8IfStringySS_tF",
-        key.offset: 667,
+        key.offset: 641,
         key.length: 80,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromConditionalProto2Extension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesElemIfString</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr=\"s:SS\">String</ref.struct></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1276,7 +1264,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesElemIfString",
             key.name: "takesElemIfString",
-            key.offset: 740,
+            key.offset: 714,
             key.length: 6
           }
         ]
@@ -1285,7 +1273,7 @@ protocol Other1 {
   },
   {
     key.kind: source.lang.swift.decl.extension.class,
-    key.offset: 751,
+    key.offset: 725,
     key.length: 56,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.class usr=\"s:16UnderscoredProto1BC\">B</ref.class>",
     key.extends: {
@@ -1299,7 +1287,7 @@ protocol Other1 {
         key.name: "fromDeprecatedProtoExtension()",
         key.usr: "s:16UnderscoredProto01_aB0PAAE014fromDeprecatedB9ExtensionyyF::SYNTHESIZED::s:16UnderscoredProto1BC",
         key.original_usr: "s:16UnderscoredProto01_aB0PAAE014fromDeprecatedB9ExtensionyyF",
-        key.offset: 770,
+        key.offset: 744,
         key.length: 35,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromDeprecatedProtoExtension</decl.name>()</decl.function.method.instance>"
       }
@@ -1329,7 +1317,7 @@ protocol Other1 {
         key.description: "U : Equatable"
       }
     ],
-    key.offset: 809,
+    key.offset: 783,
     key.length: 398,
     key.fully_annotated_decl: "<decl.class><syntaxtype.keyword>class</syntaxtype.keyword> <decl.name>C</decl.name>&lt;<decl.generic_type_param usr=\"s:16UnderscoredProto1CC1Uxmfp\"><decl.generic_type_param.name>U</decl.generic_type_param.name></decl.generic_type_param>, <decl.generic_type_param usr=\"s:16UnderscoredProto1CC1Vq_mfp\"><decl.generic_type_param.name>V</decl.generic_type_param.name></decl.generic_type_param>&gt; : <ref.class usr=\"s:16UnderscoredProto1BC\">B</ref.class>&lt;<ref.struct usr=\"s:SS\">String</ref.struct>&gt; <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Uxmfp\">U</ref.generic_type_param> : <ref.protocol usr=\"s:SQ\">Equatable</ref.protocol></decl.generic_type_requirement></decl.class>",
     key.inherits: [
@@ -1344,7 +1332,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fromC(takesUIfEquatable:)",
         key.usr: "s:16UnderscoredProto1CC5fromC17takesUIfEquatableyx_tF",
-        key.offset: 862,
+        key.offset: 836,
         key.length: 50,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromC</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesUIfEquatable</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Uxmfp\">U</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1352,7 +1340,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesUIfEquatable",
             key.name: "takesUIfEquatable",
-            key.offset: 910,
+            key.offset: 884,
             key.length: 1
           }
         ]
@@ -1361,7 +1349,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.typealias,
         key.name: "Elem1",
         key.usr: "s:16UnderscoredProto1CC5Elem1a",
-        key.offset: 918,
+        key.offset: 892,
         key.length: 19,
         key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <decl.name>Elem1</decl.name> = <ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Vq_mfp\">V</ref.generic_type_param></decl.typealias>",
         key.conforms: [
@@ -1376,7 +1364,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.typealias,
         key.name: "Elem2",
         key.usr: "s:16UnderscoredProto1CC5Elem2a",
-        key.offset: 943,
+        key.offset: 917,
         key.length: 19,
         key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <decl.name>Elem2</decl.name> = <ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Uxmfp\">U</ref.generic_type_param></decl.typealias>",
         key.conforms: [
@@ -1391,7 +1379,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fromCConditionlExtension(takesU:)",
         key.usr: "s:16UnderscoredProto1CC24fromCConditionlExtension6takesUyx_tF",
-        key.offset: 968,
+        key.offset: 942,
         key.length: 47,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromCConditionlExtension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesU</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Uxmfp\">U</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1399,7 +1387,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesU",
             key.name: "takesU",
-            key.offset: 1013,
+            key.offset: 987,
             key.length: 1
           }
         ]
@@ -1409,7 +1397,7 @@ protocol Other1 {
         key.name: "fromProto4Extension(takesElem2IfEquatable:)",
         key.usr: "s:16UnderscoredProto01_A6Proto4PAAE04fromC9Extension21takesElem2IfEquatabley0G0Qz_tF::SYNTHESIZED::s:16UnderscoredProto1CC",
         key.original_usr: "s:16UnderscoredProto01_A6Proto4PAAE04fromC9Extension21takesElem2IfEquatabley0G0Qz_tF",
-        key.offset: 1021,
+        key.offset: 995,
         key.length: 72,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromProto4Extension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesElem2IfEquatable</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Uxmfp\">U</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1417,7 +1405,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesElem2IfEquatable",
             key.name: "takesElem2IfEquatable",
-            key.offset: 1091,
+            key.offset: 1065,
             key.length: 1
           }
         ]
@@ -1427,7 +1415,7 @@ protocol Other1 {
         key.name: "fromProto3Extension(takesElem1:)",
         key.usr: "s:16UnderscoredProto01_A6Proto3PAAE04fromC9Extension10takesElem1y0G0Qz_tF::SYNTHESIZED::s:16UnderscoredProto1CC",
         key.original_usr: "s:16UnderscoredProto01_A6Proto3PAAE04fromC9Extension10takesElem1y0G0Qz_tF",
-        key.offset: 1099,
+        key.offset: 1073,
         key.length: 50,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromProto3Extension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesElem1</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Vq_mfp\">V</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1435,7 +1423,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesElem1",
             key.name: "takesElem1",
-            key.offset: 1147,
+            key.offset: 1121,
             key.length: 1
           }
         ]
@@ -1445,7 +1433,7 @@ protocol Other1 {
         key.name: "fromProto3Extension(takesElem2:)",
         key.usr: "s:16UnderscoredProto01_A6Proto3PAAE04fromC9Extension10takesElem2y0G0Qz_tF::SYNTHESIZED::s:16UnderscoredProto1CC",
         key.original_usr: "s:16UnderscoredProto01_A6Proto3PAAE04fromC9Extension10takesElem2y0G0Qz_tF",
-        key.offset: 1155,
+        key.offset: 1129,
         key.length: 50,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromProto3Extension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesElem2</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Uxmfp\">U</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1453,7 +1441,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesElem2",
             key.name: "takesElem2",
-            key.offset: 1203,
+            key.offset: 1177,
             key.length: 1
           }
         ]
@@ -1467,7 +1455,7 @@ protocol Other1 {
         key.description: "U : Hashable"
       }
     ],
-    key.offset: 1209,
+    key.offset: 1183,
     key.length: 110,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.class usr=\"s:16UnderscoredProto1CC\">C</ref.class> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Uxmfp\">U</ref.generic_type_param> : <ref.protocol usr=\"s:SH\">Hashable</ref.protocol></decl.generic_type_requirement>",
     key.extends: {
@@ -1481,7 +1469,7 @@ protocol Other1 {
         key.name: "fromProto4Extension(takesElem2IfHashable:)",
         key.usr: "s:16UnderscoredProto01_A6Proto4PAASH5Elem2RpzrlE04fromC9Extension05takesD10IfHashableyAE_tF::SYNTHESIZED::s:16UnderscoredProto1CC",
         key.original_usr: "s:16UnderscoredProto01_A6Proto4PAASH5Elem2RpzrlE04fromC9Extension05takesD10IfHashableyAE_tF",
-        key.offset: 1247,
+        key.offset: 1221,
         key.length: 70,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromProto4Extension</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesElem2IfHashable</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1CC1Uxmfp\">U</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1489,7 +1477,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesElem2IfHashable",
             key.name: "takesElem2IfHashable",
-            key.offset: 1315,
+            key.offset: 1289,
             key.length: 1
           }
         ]
@@ -1508,7 +1496,7 @@ protocol Other1 {
         key.name: "U"
       }
     ],
-    key.offset: 1321,
+    key.offset: 1295,
     key.length: 70,
     key.fully_annotated_decl: "<decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>D</decl.name>&lt;<decl.generic_type_param usr=\"s:16UnderscoredProto1DV1Txmfp\"><decl.generic_type_param.name>T</decl.generic_type_param.name></decl.generic_type_param>, <decl.generic_type_param usr=\"s:16UnderscoredProto1DV1Uq_mfp\"><decl.generic_type_param.name>U</decl.generic_type_param.name></decl.generic_type_param>&gt;</decl.struct>",
     key.entities: [
@@ -1516,7 +1504,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.name: "fromD(takesT:takesU:)",
         key.usr: "s:16UnderscoredProto1DV5fromD6takesT0D1Uyx_q_tF",
-        key.offset: 1343,
+        key.offset: 1317,
         key.length: 46,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromD</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesT</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1DV1Txmfp\">T</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>, <decl.var.parameter><decl.var.parameter.argument_label>takesU</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1DV1Uq_mfp\">U</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1524,14 +1512,14 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesT",
             key.name: "takesT",
-            key.offset: 1369,
+            key.offset: 1343,
             key.length: 1
           },
           {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesU",
             key.name: "takesU",
-            key.offset: 1387,
+            key.offset: 1361,
             key.length: 1
           }
         ]
@@ -1553,7 +1541,7 @@ protocol Other1 {
         key.description: "T : Equatable"
       }
     ],
-    key.offset: 1393,
+    key.offset: 1367,
     key.length: 59,
     key.fully_annotated_decl: "<decl.extension.struct><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.struct usr=\"s:16UnderscoredProto1DV\">D</ref.struct></decl.name> : <ref.protocol usr=\"s:16UnderscoredProto05_SomeB0P\">_SomeProto</ref.protocol> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1DV1Txmfp\">T</ref.generic_type_param> : <ref.protocol usr=\"s:SQ\">Equatable</ref.protocol></decl.generic_type_requirement></decl.extension.struct>",
     key.conforms: [
@@ -1573,7 +1561,7 @@ protocol Other1 {
         key.kind: source.lang.swift.decl.typealias,
         key.name: "Item",
         key.usr: "s:16UnderscoredProto1DVAASQRzrlE4Itema",
-        key.offset: 1432,
+        key.offset: 1406,
         key.length: 18,
         key.fully_annotated_decl: "<decl.typealias><syntaxtype.keyword>typealias</syntaxtype.keyword> <decl.name>Item</decl.name> = <ref.generic_type_param usr=\"s:16UnderscoredProto1DVAASQRzrlE1Txmfp\">T</ref.generic_type_param></decl.typealias>",
         key.conforms: [
@@ -1604,7 +1592,7 @@ protocol Other1 {
         key.description: "T : Equatable"
       }
     ],
-    key.offset: 1454,
+    key.offset: 1428,
     key.length: 135,
     key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"s:16UnderscoredProto1DV\">D</ref.struct> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1DV1Txmfp\">T</ref.generic_type_param> : <ref.protocol usr=\"s:16UnderscoredProto6Other1P\">Other1</ref.protocol></decl.generic_type_requirement>, <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1DV1Txmfp\">T</ref.generic_type_param> : <ref.protocol usr=\"s:SQ\">Equatable</ref.protocol></decl.generic_type_requirement>",
     key.extends: {
@@ -1618,7 +1606,7 @@ protocol Other1 {
         key.name: "fromSomeProtoExtensionSplitConditions(takesItemIfOther1:)",
         key.usr: "s:16UnderscoredProto05_SomeB0PA2A6Other14ItemRpzrlE04fromcB24ExtensionSplitConditions05takese2IfD0yAF_tF::SYNTHESIZED::s:16UnderscoredProto1DV",
         key.original_usr: "s:16UnderscoredProto05_SomeB0PA2A6Other14ItemRpzrlE04fromcB24ExtensionSplitConditions05takese2IfD0yAF_tF",
-        key.offset: 1505,
+        key.offset: 1479,
         key.length: 82,
         key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromSomeProtoExtensionSplitConditions</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesItemIfOther1</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1DV1Txmfp\">T</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
@@ -1626,7 +1614,7 @@ protocol Other1 {
             key.kind: source.lang.swift.decl.var.local,
             key.keyword: "takesItemIfOther1",
             key.name: "takesItemIfOther1",
-            key.offset: 1585,
+            key.offset: 1559,
             key.length: 1
           }
         ]
@@ -1637,7 +1625,7 @@ protocol Other1 {
     key.kind: source.lang.swift.decl.protocol,
     key.name: "Other1",
     key.usr: "s:16UnderscoredProto6Other1P",
-    key.offset: 1591,
+    key.offset: 1565,
     key.length: 19,
     key.fully_annotated_decl: "<decl.protocol><syntaxtype.keyword>protocol</syntaxtype.keyword> <decl.name>Other1</decl.name></decl.protocol>"
   }
diff --git a/test/SourceKit/DocumentStructure/Inputs/raw-identifiers.swift b/test/SourceKit/DocumentStructure/Inputs/raw-identifiers.swift
new file mode 100644
index 0000000000000..61b94981ce717
--- /dev/null
+++ b/test/SourceKit/DocumentStructure/Inputs/raw-identifiers.swift
@@ -0,0 +1,13 @@
+struct `A.B` {
+  func `foo bar`(`a b`: Int, c: Int, `$`: String) {}
+  func `3four`() {}
+  func `baz`(`x`: Int) {}
+}
+extension `A.B` {}
+
+struct Outer {
+  struct Inner {}
+}
+extension Outer.Inner {}
+
+func + (lhs: `A.B`, rhs: `A.B`) -> `A.B` { lhs }
diff --git a/test/SourceKit/DocumentStructure/structure.swift b/test/SourceKit/DocumentStructure/structure.swift
index 6ee2958265e01..5b840fe4e4f50 100644
--- a/test/SourceKit/DocumentStructure/structure.swift
+++ b/test/SourceKit/DocumentStructure/structure.swift
@@ -7,6 +7,9 @@
 // RUN: %sourcekitd-test -req=structure %S/../Inputs/placeholders.swift | %sed_clean > %t.placeholders.response
 // RUN: %diff -u %s.placeholders.response %t.placeholders.response
 
+// RUN: %sourcekitd-test -req=structure %S/Inputs/raw-identifiers.swift | %sed_clean > %t.raw-identifiers.swift.response
+// RUN: %diff -u %s.raw-identifiers.swift.response %t.raw-identifiers.swift.response
+
 // RUN: %sourcekitd-test -req=structure %S/Inputs/main.swift -name -foobar | %sed_clean > %t.foobar.response
 // RUN: %diff -u %s.foobar.response %t.foobar.response
 
diff --git a/test/SourceKit/DocumentStructure/structure.swift.empty.response b/test/SourceKit/DocumentStructure/structure.swift.empty.response
index f362c577bc8c2..b33850b7693cf 100644
--- a/test/SourceKit/DocumentStructure/structure.swift.empty.response
+++ b/test/SourceKit/DocumentStructure/structure.swift.empty.response
@@ -1113,7 +1113,7 @@
       key.kind: source.lang.swift.decl.var.global,
       key.accessibility: source.lang.swift.accessibility.internal,
       key.setter_accessibility: source.lang.swift.accessibility.internal,
-      key.name: "$",
+      key.name: "`$`",
       key.offset: 1982,
       key.length: 24,
       key.nameoffset: 1999,
diff --git a/test/SourceKit/DocumentStructure/structure.swift.foobar.response b/test/SourceKit/DocumentStructure/structure.swift.foobar.response
index 0279f3a4e24d7..e97d96ea110f6 100644
--- a/test/SourceKit/DocumentStructure/structure.swift.foobar.response
+++ b/test/SourceKit/DocumentStructure/structure.swift.foobar.response
@@ -1113,7 +1113,7 @@
       key.kind: source.lang.swift.decl.var.global,
       key.accessibility: source.lang.swift.accessibility.internal,
       key.setter_accessibility: source.lang.swift.accessibility.internal,
-      key.name: "$",
+      key.name: "`$`",
       key.offset: 1982,
       key.length: 24,
       key.nameoffset: 1999,
diff --git a/test/SourceKit/DocumentStructure/structure.swift.invalid.response b/test/SourceKit/DocumentStructure/structure.swift.invalid.response
index 612f5146fae7f..8bbd0ea196fba 100644
--- a/test/SourceKit/DocumentStructure/structure.swift.invalid.response
+++ b/test/SourceKit/DocumentStructure/structure.swift.invalid.response
@@ -60,7 +60,7 @@
     {
       key.kind: source.lang.swift.decl.class,
       key.accessibility: source.lang.swift.accessibility.internal,
-      key.name: "3",
+      key.name: "`3`",
       key.offset: 84,
       key.length: 10,
       key.nameoffset: 90,
diff --git a/test/SourceKit/DocumentStructure/structure.swift.placeholders.response b/test/SourceKit/DocumentStructure/structure.swift.placeholders.response
index 575b749ac5374..a271d4876db60 100644
--- a/test/SourceKit/DocumentStructure/structure.swift.placeholders.response
+++ b/test/SourceKit/DocumentStructure/structure.swift.placeholders.response
@@ -6,7 +6,7 @@
     {
       key.kind: source.lang.swift.decl.class,
       key.accessibility: source.lang.swift.accessibility.internal,
-      key.name: "<#MyCls#>",
+      key.name: "`<#MyCls#>`",
       key.offset: 0,
       key.length: 35,
       key.nameoffset: 6,
@@ -29,7 +29,7 @@
     {
       key.kind: source.lang.swift.decl.function.free,
       key.accessibility: source.lang.swift.accessibility.internal,
-      key.name: "<#test1#>()",
+      key.name: "`<#test1#>`()",
       key.offset: 37,
       key.length: 52,
       key.nameoffset: 42,
@@ -56,7 +56,7 @@
           key.substructure: [
             {
               key.kind: source.lang.swift.decl.var.local,
-              key.name: "<#name#>",
+              key.name: "`<#name#>`",
               key.offset: 63,
               key.length: 8,
               key.nameoffset: 63,
diff --git a/test/SourceKit/DocumentStructure/structure.swift.raw-identifiers.swift.response b/test/SourceKit/DocumentStructure/structure.swift.raw-identifiers.swift.response
new file mode 100644
index 0000000000000..44ac96cbe8469
--- /dev/null
+++ b/test/SourceKit/DocumentStructure/structure.swift.raw-identifiers.swift.response
@@ -0,0 +1,165 @@
+{
+  key.offset: 0,
+  key.length: 246,
+  key.diagnostic_stage: source.diagnostic.stage.swift.parse,
+  key.substructure: [
+    {
+      key.kind: source.lang.swift.decl.struct,
+      key.accessibility: source.lang.swift.accessibility.internal,
+      key.name: "`A.B`",
+      key.offset: 0,
+      key.length: 115,
+      key.nameoffset: 7,
+      key.namelength: 3,
+      key.bodyoffset: 14,
+      key.bodylength: 100,
+      key.substructure: [
+        {
+          key.kind: source.lang.swift.decl.function.method.instance,
+          key.accessibility: source.lang.swift.accessibility.internal,
+          key.name: "`foo bar`(`a b`:c:`$`:)",
+          key.offset: 17,
+          key.length: 50,
+          key.nameoffset: 22,
+          key.namelength: 42,
+          key.bodyoffset: 66,
+          key.bodylength: 0,
+          key.substructure: [
+            {
+              key.kind: source.lang.swift.decl.var.parameter,
+              key.name: "`a b`",
+              key.offset: 32,
+              key.length: 10,
+              key.typename: "Int",
+              key.nameoffset: 32,
+              key.namelength: 3
+            },
+            {
+              key.kind: source.lang.swift.decl.var.parameter,
+              key.name: "c",
+              key.offset: 44,
+              key.length: 6,
+              key.typename: "Int",
+              key.nameoffset: 44,
+              key.namelength: 1
+            },
+            {
+              key.kind: source.lang.swift.decl.var.parameter,
+              key.name: "`$`",
+              key.offset: 52,
+              key.length: 11,
+              key.typename: "String",
+              key.nameoffset: 52,
+              key.namelength: 1
+            }
+          ]
+        },
+        {
+          key.kind: source.lang.swift.decl.function.method.instance,
+          key.accessibility: source.lang.swift.accessibility.internal,
+          key.name: "`3four`()",
+          key.offset: 70,
+          key.length: 17,
+          key.nameoffset: 75,
+          key.namelength: 9,
+          key.bodyoffset: 86,
+          key.bodylength: 0
+        },
+        {
+          key.kind: source.lang.swift.decl.function.method.instance,
+          key.accessibility: source.lang.swift.accessibility.internal,
+          key.name: "baz(x:)",
+          key.offset: 90,
+          key.length: 23,
+          key.nameoffset: 95,
+          key.namelength: 15,
+          key.bodyoffset: 112,
+          key.bodylength: 0,
+          key.substructure: [
+            {
+              key.kind: source.lang.swift.decl.var.parameter,
+              key.name: "x",
+              key.offset: 101,
+              key.length: 8,
+              key.typename: "Int",
+              key.nameoffset: 101,
+              key.namelength: 1
+            }
+          ]
+        }
+      ]
+    },
+    {
+      key.kind: source.lang.swift.decl.extension,
+      key.name: "`A.B`",
+      key.offset: 116,
+      key.length: 18,
+      key.nameoffset: 126,
+      key.namelength: 5,
+      key.bodyoffset: 133,
+      key.bodylength: 0
+    },
+    {
+      key.kind: source.lang.swift.decl.struct,
+      key.accessibility: source.lang.swift.accessibility.internal,
+      key.name: "Outer",
+      key.offset: 136,
+      key.length: 34,
+      key.nameoffset: 143,
+      key.namelength: 5,
+      key.bodyoffset: 150,
+      key.bodylength: 19,
+      key.substructure: [
+        {
+          key.kind: source.lang.swift.decl.struct,
+          key.accessibility: source.lang.swift.accessibility.internal,
+          key.name: "Inner",
+          key.offset: 153,
+          key.length: 15,
+          key.nameoffset: 160,
+          key.namelength: 5,
+          key.bodyoffset: 167,
+          key.bodylength: 0
+        }
+      ]
+    },
+    {
+      key.kind: source.lang.swift.decl.extension,
+      key.name: "Outer.Inner",
+      key.offset: 171,
+      key.length: 24,
+      key.nameoffset: 181,
+      key.namelength: 11,
+      key.bodyoffset: 194,
+      key.bodylength: 0
+    },
+    {
+      key.kind: source.lang.swift.decl.function.free,
+      key.accessibility: source.lang.swift.accessibility.internal,
+      key.name: "+(_:_:)",
+      key.offset: 197,
+      key.length: 48,
+      key.typename: "`A.B`",
+      key.nameoffset: 202,
+      key.namelength: 26,
+      key.bodyoffset: 239,
+      key.bodylength: 5,
+      key.substructure: [
+        {
+          key.kind: source.lang.swift.decl.var.parameter,
+          key.name: "lhs",
+          key.offset: 205,
+          key.length: 10,
+          key.typename: "`A.B`"
+        },
+        {
+          key.kind: source.lang.swift.decl.var.parameter,
+          key.name: "rhs",
+          key.offset: 217,
+          key.length: 10,
+          key.typename: "`A.B`"
+        }
+      ]
+    }
+  ]
+}
diff --git a/test/SourceKit/DocumentStructure/structure.swift.response b/test/SourceKit/DocumentStructure/structure.swift.response
index 6c69cef5307e6..b001a5484be4d 100644
--- a/test/SourceKit/DocumentStructure/structure.swift.response
+++ b/test/SourceKit/DocumentStructure/structure.swift.response
@@ -1113,7 +1113,7 @@
       key.kind: source.lang.swift.decl.var.global,
       key.accessibility: source.lang.swift.accessibility.internal,
       key.setter_accessibility: source.lang.swift.accessibility.internal,
-      key.name: "$",
+      key.name: "`$`",
       key.offset: 1982,
       key.length: 24,
       key.nameoffset: 1999,
diff --git a/test/SourceKit/InterfaceGen/Inputs/module.modulemap b/test/SourceKit/InterfaceGen/Inputs/module.modulemap
new file mode 100644
index 0000000000000..2db9ba676aa7f
--- /dev/null
+++ b/test/SourceKit/InterfaceGen/Inputs/module.modulemap
@@ -0,0 +1,4 @@
+module UsesCXX20 {
+  header "uses-cxx20.h"
+  export *
+}
diff --git a/test/SourceKit/InterfaceGen/Inputs/uses-cxx20.h b/test/SourceKit/InterfaceGen/Inputs/uses-cxx20.h
new file mode 100644
index 0000000000000..9370c7270cc6c
--- /dev/null
+++ b/test/SourceKit/InterfaceGen/Inputs/uses-cxx20.h
@@ -0,0 +1,3 @@
+#include <span>
+
+using MySpanOfInt = std::span<int>;
diff --git a/test/SourceKit/InterfaceGen/gen_clang_cxx_module.swift b/test/SourceKit/InterfaceGen/gen_clang_cxx_module.swift
index 2bb9a31c2da0f..ee7f19af9a439 100644
--- a/test/SourceKit/InterfaceGen/gen_clang_cxx_module.swift
+++ b/test/SourceKit/InterfaceGen/gen_clang_cxx_module.swift
@@ -1,7 +1,10 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
-// RUN: %sourcekitd-test -req=interface-gen -module CxxModule -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -I %t/Inputs -target %target-triple %clang-importer-sdk-nosource | %FileCheck %s
+// The interface should fail to generate with C++ interop disabled:
+// RUN: not %sourcekitd-test -req=interface-gen -module CxxModule -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -I %t/Inputs -target %target-triple %clang-importer-sdk-nosource
+
+// With C++ interop enabled, it should succeed:
 // RUN: %sourcekitd-test -req=interface-gen -module CxxModule -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -cxx-interoperability-mode=default -I %t/Inputs -target %target-triple %clang-importer-sdk-nosource | %FileCheck %s
 
 
diff --git a/test/SourceKit/InterfaceGen/gen_clang_cxx_module_with_cxx20.swift b/test/SourceKit/InterfaceGen/gen_clang_cxx_module_with_cxx20.swift
new file mode 100644
index 0000000000000..dc0758966dfc0
--- /dev/null
+++ b/test/SourceKit/InterfaceGen/gen_clang_cxx_module_with_cxx20.swift
@@ -0,0 +1,10 @@
+// First, check that we error out for older C++ standards.
+// RUN: not %sourcekitd-test -req=interface-gen -module UsesCXX20 -- -cxx-interoperability-mode=default -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -I %S/Inputs -target %target-triple -sdk %sdk
+
+// Now make sure we emit the correct interface for std::span if C++20 is enabled.
+// RUN: %sourcekitd-test -req=interface-gen -module UsesCXX20 -- -cxx-interoperability-mode=default -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -I %S/Inputs -target %target-triple -sdk %sdk -Xcc -std=c++20 | %FileCheck %s
+
+// FIXME: older libstdc++ version on Swift CI does not support C++20
+// UNSUPPORTED: OS=linux-gnu
+
+// CHECK: public typealias MySpanOfInt = std.span<
diff --git a/test/SourceKit/InterfaceGen/gen_clang_libcxx_sdk_module.swift b/test/SourceKit/InterfaceGen/gen_clang_libcxx_sdk_module.swift
index ad0cf1478f2d3..52cbf8418763c 100644
--- a/test/SourceKit/InterfaceGen/gen_clang_libcxx_sdk_module.swift
+++ b/test/SourceKit/InterfaceGen/gen_clang_libcxx_sdk_module.swift
@@ -1,6 +1,19 @@
-// RUN: %sourcekitd-test -req=interface-gen -module CxxStdlib -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -cxx-interoperability-mode=default -target %target-triple -sdk %sdk | %FileCheck %s
+// RUN: %empty-directory(%t)
+// RUN: %target-clangxx %S/../../Interop/Cxx/stdlib/Inputs/check-libcxx-version.cpp -o %t/check-libcxx-version
+// RUN: %target-codesign %t/check-libcxx-version
+
+// Since this test runs check-libcxx-version, it requires execution.
+// REQUIRES: executable_test
+
+// RUN: %target-run %t/check-libcxx-version || %sourcekitd-test -req=interface-gen -module CxxStdlib -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -cxx-interoperability-mode=default -target %target-triple -sdk %sdk | %FileCheck %s --check-prefix CHECK-MONO
+// RUN: not %target-run %t/check-libcxx-version || %sourcekitd-test -req=interface-gen -module CxxStdlib -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -cxx-interoperability-mode=default -target %target-triple -sdk %sdk | %FileCheck %s --check-prefix CHECK-SPLIT
 
 // REQUIRES: OS=macosx
 
-// CHECK: import {{CxxStdlib.vector|std_vector}}
-// CHECK: extension std.basic_string<CChar, std.__1.char_traits<CChar>, std.__1.allocator<CChar>> {
+// CHECK-MONO-NOT: import CxxStdlib{{$}}
+// CHECK-MONO: import CxxStdlib.vector
+// CHECK-MONO: extension std.basic_string<CChar, std.__1.char_traits<CChar>, std.__1.allocator<CChar>> {
+
+// CHECK-SPLIT-NOT: import CxxStdlib{{$}}
+// CHECK-SPLIT: import std_vector
+// CHECK-SPLIT: extension std.basic_string<CChar, std.__1.char_traits<CChar>, std.__1.allocator<CChar>> {
diff --git a/test/SourceKit/InterfaceGen/gen_clang_mixed_lang_fmwk_cxx_module.swift b/test/SourceKit/InterfaceGen/gen_clang_mixed_lang_fmwk_cxx_module.swift
index 413dda8adb16f..07fd707fd3b83 100644
--- a/test/SourceKit/InterfaceGen/gen_clang_mixed_lang_fmwk_cxx_module.swift
+++ b/test/SourceKit/InterfaceGen/gen_clang_mixed_lang_fmwk_cxx_module.swift
@@ -3,7 +3,7 @@
 
 // RUN: %target-swift-frontend -emit-module %t/TestFmSwift.swift -module-name TestFm -enable-experimental-cxx-interop -F %t -o %t/TestFm.swiftmodule -import-underlying-module
 
-// RUN: %sourcekitd-test -req=interface-gen -module TestFm -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -I %t -target %target-triple %clang-importer-sdk-nosource | %FileCheck %s
+// RUN: %sourcekitd-test -req=interface-gen -module TestFm -- -cxx-interoperability-mode=default -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import -I %t -target %target-triple %clang-importer-sdk-nosource | %FileCheck %s
 
 //--- TestFm.framework/Headers/TestFm.h
 #pragma once
diff --git a/test/SourceKit/InterfaceGen/gen_clang_module.swift b/test/SourceKit/InterfaceGen/gen_clang_module.swift
index f7a0318fdf0fa..1d6239cf32e4b 100644
--- a/test/SourceKit/InterfaceGen/gen_clang_module.swift
+++ b/test/SourceKit/InterfaceGen/gen_clang_module.swift
@@ -31,7 +31,7 @@ var x: FooClassBase
 
 // RUN: %sourcekitd-test -req=interface-gen-open -module Foo -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import  -I %t.overlays -F %S/../Inputs/libIDE-mock-sdk \
 // RUN:         -target %target-triple %clang-importer-sdk-nosource -I %t \
-// RUN:      == -req=cursor -pos=191:67 | %FileCheck -check-prefix=CHECK1 %s
+// RUN:      == -req=cursor -pos=190:57 | %FileCheck -check-prefix=CHECK1 %s
 // The cursor points to 'FooClassBase' inside the list of base classes, see 'gen_clang_module.swift.response'
 
 // RUN: %sourcekitd-test -req=interface-gen-open -module Foo -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import  -I %t.overlays -F %S/../Inputs/libIDE-mock-sdk \
@@ -47,7 +47,7 @@ var x: FooClassBase
 
 // RUN: %sourcekitd-test -req=interface-gen-open -module Foo -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import  -I %t.overlays -F %S/../Inputs/libIDE-mock-sdk \
 // RUN:         -target %target-triple %clang-importer-sdk-nosource -I %t \
-// RUN:      == -req=cursor -pos=211:20 | %FileCheck -check-prefix=CHECK2 %s
+// RUN:      == -req=cursor -pos=210:15 | %FileCheck -check-prefix=CHECK2 %s
 // The cursor points inside the interface, see 'gen_clang_module.swift.response'
 
 // CHECK2: source.lang.swift.decl.function.method.instance ({{.*}}Foo.framework/Headers/Foo.h:170:10-170:27)
@@ -61,7 +61,7 @@ var x: FooClassBase
 // RUN:      == -req=find-usr -usr "c:objc(cs)FooClassDerived(im)fooInstanceFunc0" | %FileCheck -check-prefix=CHECK-USR %s
 // The returned line:col points inside the interface, see 'gen_clang_module.swift.response'
 
-// CHECK-USR: (211:15-211:33)
+// CHECK-USR: (210:15-210:33)
 
 // RUN: %sourcekitd-test -req=interface-gen-open -module Foo -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import  -I %t.overlays -F %S/../Inputs/libIDE-mock-sdk \
 // RUN:         -target %target-triple %clang-importer-sdk-nosource -I %t \
diff --git a/test/SourceKit/InterfaceGen/gen_clang_module.swift.helper.explicit.response b/test/SourceKit/InterfaceGen/gen_clang_module.swift.helper.explicit.response
index d08ec5d8ba3b2..db2e23f4732d6 100644
--- a/test/SourceKit/InterfaceGen/gen_clang_module.swift.helper.explicit.response
+++ b/test/SourceKit/InterfaceGen/gen_clang_module.swift.helper.explicit.response
@@ -1,54 +1,53 @@
-
 public func fooHelperExplicitFrameworkFunc1(_ a: Int32) -> Int32
 
 
 [
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 1,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 8,
+    key.offset: 7,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 13,
+    key.offset: 12,
     key.length: 31
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 45,
+    key.offset: 44,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 47,
+    key.offset: 46,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 50,
+    key.offset: 49,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 60,
+    key.offset: 59,
     key.length: 5
   }
 ]
 [
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 50,
+    key.offset: 49,
     key.length: 5,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 60,
+    key.offset: 59,
     key.length: 5,
     key.is_system: 1
   }
@@ -58,14 +57,14 @@ public func fooHelperExplicitFrameworkFunc1(_ a: Int32) -> Int32
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooHelperExplicitFrameworkFunc1(_:)",
-    key.offset: 8,
+    key.offset: 7,
     key.length: 57,
     key.typename: "Int32",
-    key.nameoffset: 13,
+    key.nameoffset: 12,
     key.namelength: 43,
     key.attributes: [
       {
-        key.offset: 1,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -74,7 +73,7 @@ public func fooHelperExplicitFrameworkFunc1(_ a: Int32) -> Int32
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "a",
-        key.offset: 45,
+        key.offset: 44,
         key.length: 10,
         key.typename: "Int32"
       }
diff --git a/test/SourceKit/InterfaceGen/gen_clang_module.swift.response b/test/SourceKit/InterfaceGen/gen_clang_module.swift.response
index 29c4977c71b2b..69adddd02b49b 100644
--- a/test/SourceKit/InterfaceGen/gen_clang_module.swift.response
+++ b/test/SourceKit/InterfaceGen/gen_clang_module.swift.response
@@ -1,6 +1,5 @@
 import Foo.FooSub
 import FooHelper
-import SwiftOnoneSupport
 
 /// Aaa.  FooEnum1.  Bbb.
 public struct FooEnum1 : Hashable, Equatable, RawRepresentable {
@@ -370,3164 +369,3154 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.offset: 25,
     key.length: 9
   },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 35,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 42,
-    key.length: 17
-  },
   {
     key.kind: source.lang.swift.syntaxtype.doccomment,
-    key.offset: 61,
+    key.offset: 36,
     key.length: 26
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 87,
+    key.offset: 62,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 94,
+    key.offset: 69,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 101,
+    key.offset: 76,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 112,
+    key.offset: 87,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 122,
+    key.offset: 97,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 133,
+    key.offset: 108,
     key.length: 16
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 157,
+    key.offset: 132,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 164,
+    key.offset: 139,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 169,
+    key.offset: 144,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 171,
+    key.offset: 146,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 181,
+    key.offset: 156,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 194,
+    key.offset: 169,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 201,
+    key.offset: 176,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 206,
+    key.offset: 181,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 216,
+    key.offset: 191,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 229,
+    key.offset: 204,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 236,
+    key.offset: 211,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 240,
+    key.offset: 215,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 250,
+    key.offset: 225,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.doccomment,
-    key.offset: 260,
+    key.offset: 235,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 287,
+    key.offset: 262,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 294,
+    key.offset: 269,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 298,
+    key.offset: 273,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 309,
+    key.offset: 284,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 320,
+    key.offset: 295,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 327,
+    key.offset: 302,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 334,
+    key.offset: 309,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 341,
+    key.offset: 316,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 352,
+    key.offset: 327,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 362,
+    key.offset: 337,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 373,
+    key.offset: 348,
     key.length: 16
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 397,
+    key.offset: 372,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 404,
+    key.offset: 379,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 409,
+    key.offset: 384,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 411,
+    key.offset: 386,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 421,
+    key.offset: 396,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 434,
+    key.offset: 409,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 441,
+    key.offset: 416,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 446,
+    key.offset: 421,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 456,
+    key.offset: 431,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 469,
+    key.offset: 444,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 476,
+    key.offset: 451,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 480,
+    key.offset: 455,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 490,
+    key.offset: 465,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 500,
+    key.offset: 475,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 507,
+    key.offset: 482,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 511,
+    key.offset: 486,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 522,
+    key.offset: 497,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 533,
+    key.offset: 508,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 540,
+    key.offset: 515,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 547,
+    key.offset: 522,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 551,
+    key.offset: 526,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 562,
+    key.offset: 537,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 573,
+    key.offset: 548,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 580,
+    key.offset: 555,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 587,
+    key.offset: 562,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 594,
+    key.offset: 569,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 605,
+    key.offset: 580,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 615,
+    key.offset: 590,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 626,
+    key.offset: 601,
     key.length: 16
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 650,
+    key.offset: 625,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 657,
+    key.offset: 632,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 662,
+    key.offset: 637,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 664,
+    key.offset: 639,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 674,
+    key.offset: 649,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 687,
+    key.offset: 662,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 694,
+    key.offset: 669,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 699,
+    key.offset: 674,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 709,
+    key.offset: 684,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 722,
+    key.offset: 697,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 729,
+    key.offset: 704,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 733,
+    key.offset: 708,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 743,
+    key.offset: 718,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 753,
+    key.offset: 728,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 760,
+    key.offset: 735,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 764,
+    key.offset: 739,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 775,
+    key.offset: 750,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 786,
+    key.offset: 761,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 793,
+    key.offset: 768,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 800,
+    key.offset: 775,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 804,
+    key.offset: 779,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 815,
+    key.offset: 790,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 826,
+    key.offset: 801,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.doccomment,
-    key.offset: 833,
+    key.offset: 808,
     key.length: 37
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 870,
+    key.offset: 845,
     key.length: 6
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     key.is_system: 1
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   {
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     key.is_system: 1
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   {
     key.kind: source.lang.swift.ref.module,
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   {
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-    key.offset: 6463,
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 ]
@@ -4184,13 +4167,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooEnum1",
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+    key.offset: 69,
     key.length: 164,
-    key.nameoffset: 101,
+    key.nameoffset: 76,
     key.namelength: 8,
-    key.bodyoffset: 151,
+    key.bodyoffset: 126,
     key.bodylength: 106,
-    key.docoffset: 61,
+    key.docoffset: 36,
     key.doclength: 26,
     key.inheritedtypes: [
       {
@@ -4205,7 +4188,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 87,
+        key.offset: 62,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4213,17 +4196,17 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 112,
+        key.offset: 87,
         key.length: 8
       },
       {
         key.kind: source.lang.swift.structure.elem.typeref,
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+        key.offset: 97,
         key.length: 9
       },
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 133,
+        key.offset: 108,
         key.length: 16
       }
     ],
@@ -4232,13 +4215,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(_:)",
-        key.offset: 164,
+        key.offset: 139,
         key.length: 24,
-        key.nameoffset: 164,
+        key.nameoffset: 139,
         key.namelength: 24,
         key.attributes: [
           {
-            key.offset: 157,
+            key.offset: 132,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4247,7 +4230,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "rawValue",
-            key.offset: 169,
+            key.offset: 144,
             key.length: 18,
             key.typename: "UInt32"
           }
@@ -4257,13 +4240,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(rawValue:)",
-        key.offset: 201,
+        key.offset: 176,
         key.length: 22,
-        key.nameoffset: 201,
+        key.nameoffset: 176,
         key.namelength: 22,
         key.attributes: [
           {
-            key.offset: 194,
+            key.offset: 169,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4272,10 +4255,10 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "rawValue",
-            key.offset: 206,
+            key.offset: 181,
             key.length: 16,
             key.typename: "UInt32",
-            key.nameoffset: 206,
+            key.nameoffset: 181,
             key.namelength: 8
           }
         ]
@@ -4285,14 +4268,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "rawValue",
-        key.offset: 236,
+        key.offset: 211,
         key.length: 20,
         key.typename: "UInt32",
-        key.nameoffset: 240,
+        key.nameoffset: 215,
         key.namelength: 8,
         key.attributes: [
           {
-            key.offset: 229,
+            key.offset: 204,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4304,18 +4287,18 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooEnum1X",
-    key.offset: 294,
+    key.offset: 269,
     key.length: 31,
     key.typename: "FooEnum1",
-    key.nameoffset: 298,
+    key.nameoffset: 273,
     key.namelength: 9,
-    key.bodyoffset: 319,
+    key.bodyoffset: 294,
     key.bodylength: 5,
-    key.docoffset: 260,
+    key.docoffset: 235,
     key.doclength: 27,
     key.attributes: [
       {
-        key.offset: 287,
+        key.offset: 262,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4325,11 +4308,11 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooEnum2",
-    key.offset: 334,
+    key.offset: 309,
     key.length: 164,
-    key.nameoffset: 341,
+    key.nameoffset: 316,
     key.namelength: 8,
-    key.bodyoffset: 391,
+    key.bodyoffset: 366,
     key.bodylength: 106,
     key.inheritedtypes: [
       {
@@ -4344,7 +4327,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 327,
+        key.offset: 302,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4352,17 +4335,17 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 352,
+        key.offset: 327,
         key.length: 8
       },
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 362,
+        key.offset: 337,
         key.length: 9
       },
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 373,
+        key.offset: 348,
         key.length: 16
       }
     ],
@@ -4371,13 +4354,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(_:)",
-        key.offset: 404,
+        key.offset: 379,
         key.length: 24,
-        key.nameoffset: 404,
+        key.nameoffset: 379,
         key.namelength: 24,
         key.attributes: [
           {
-            key.offset: 397,
+            key.offset: 372,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4386,7 +4369,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "rawValue",
-            key.offset: 409,
+            key.offset: 384,
             key.length: 18,
             key.typename: "UInt32"
           }
@@ -4396,13 +4379,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(rawValue:)",
-        key.offset: 441,
+        key.offset: 416,
         key.length: 22,
-        key.nameoffset: 441,
+        key.nameoffset: 416,
         key.namelength: 22,
         key.attributes: [
           {
-            key.offset: 434,
+            key.offset: 409,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4411,10 +4394,10 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "rawValue",
-            key.offset: 446,
+            key.offset: 421,
             key.length: 16,
             key.typename: "UInt32",
-            key.nameoffset: 446,
+            key.nameoffset: 421,
             key.namelength: 8
           }
         ]
@@ -4424,14 +4407,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "rawValue",
-        key.offset: 476,
+        key.offset: 451,
         key.length: 20,
         key.typename: "UInt32",
-        key.nameoffset: 480,
+        key.nameoffset: 455,
         key.namelength: 8,
         key.attributes: [
           {
-            key.offset: 469,
+            key.offset: 444,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4443,16 +4426,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooEnum2X",
-    key.offset: 507,
+    key.offset: 482,
     key.length: 31,
     key.typename: "FooEnum2",
-    key.nameoffset: 511,
+    key.nameoffset: 486,
     key.namelength: 9,
-    key.bodyoffset: 532,
+    key.bodyoffset: 507,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 500,
+        key.offset: 475,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4462,16 +4445,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooEnum2Y",
-    key.offset: 547,
+    key.offset: 522,
     key.length: 31,
     key.typename: "FooEnum2",
-    key.nameoffset: 551,
+    key.nameoffset: 526,
     key.namelength: 9,
-    key.bodyoffset: 572,
+    key.bodyoffset: 547,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 540,
+        key.offset: 515,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4481,11 +4464,11 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooEnum3",
-    key.offset: 587,
+    key.offset: 562,
     key.length: 164,
-    key.nameoffset: 594,
+    key.nameoffset: 569,
     key.namelength: 8,
-    key.bodyoffset: 644,
+    key.bodyoffset: 619,
     key.bodylength: 106,
     key.inheritedtypes: [
       {
@@ -4500,7 +4483,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 580,
+        key.offset: 555,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4508,17 +4491,17 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 605,
+        key.offset: 580,
         key.length: 8
       },
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 615,
+        key.offset: 590,
         key.length: 9
       },
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 626,
+        key.offset: 601,
         key.length: 16
       }
     ],
@@ -4527,13 +4510,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(_:)",
-        key.offset: 657,
+        key.offset: 632,
         key.length: 24,
-        key.nameoffset: 657,
+        key.nameoffset: 632,
         key.namelength: 24,
         key.attributes: [
           {
-            key.offset: 650,
+            key.offset: 625,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4542,7 +4525,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "rawValue",
-            key.offset: 662,
+            key.offset: 637,
             key.length: 18,
             key.typename: "UInt32"
           }
@@ -4552,13 +4535,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(rawValue:)",
-        key.offset: 694,
+        key.offset: 669,
         key.length: 22,
-        key.nameoffset: 694,
+        key.nameoffset: 669,
         key.namelength: 22,
         key.attributes: [
           {
-            key.offset: 687,
+            key.offset: 662,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4567,10 +4550,10 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "rawValue",
-            key.offset: 699,
+            key.offset: 674,
             key.length: 16,
             key.typename: "UInt32",
-            key.nameoffset: 699,
+            key.nameoffset: 674,
             key.namelength: 8
           }
         ]
@@ -4580,14 +4563,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "rawValue",
-        key.offset: 729,
+        key.offset: 704,
         key.length: 20,
         key.typename: "UInt32",
-        key.nameoffset: 733,
+        key.nameoffset: 708,
         key.namelength: 8,
         key.attributes: [
           {
-            key.offset: 722,
+            key.offset: 697,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4599,16 +4582,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooEnum3X",
-    key.offset: 760,
+    key.offset: 735,
     key.length: 31,
     key.typename: "FooEnum3",
-    key.nameoffset: 764,
+    key.nameoffset: 739,
     key.namelength: 9,
-    key.bodyoffset: 785,
+    key.bodyoffset: 760,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 753,
+        key.offset: 728,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4618,16 +4601,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooEnum3Y",
-    key.offset: 800,
+    key.offset: 775,
     key.length: 31,
     key.typename: "FooEnum3",
-    key.nameoffset: 804,
+    key.nameoffset: 779,
     key.namelength: 9,
-    key.bodyoffset: 825,
+    key.bodyoffset: 800,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 793,
+        key.offset: 768,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4637,13 +4620,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.enum,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooComparisonResult",
-    key.offset: 877,
+    key.offset: 852,
     key.length: 124,
-    key.nameoffset: 882,
+    key.nameoffset: 857,
     key.namelength: 19,
-    key.bodyoffset: 909,
+    key.bodyoffset: 884,
     key.bodylength: 91,
-    key.docoffset: 833,
+    key.docoffset: 808,
     key.doclength: 37,
     key.inheritedtypes: [
       {
@@ -4652,7 +4635,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 870,
+        key.offset: 845,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4660,28 +4643,28 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 904,
+        key.offset: 879,
         key.length: 3
       }
     ],
     key.substructure: [
       {
         key.kind: source.lang.swift.decl.enumcase,
-        key.offset: 915,
+        key.offset: 890,
         key.length: 26,
         key.substructure: [
           {
             key.kind: source.lang.swift.decl.enumelement,
             key.accessibility: source.lang.swift.accessibility.public,
             key.name: "orderedAscending",
-            key.offset: 920,
+            key.offset: 895,
             key.length: 21,
-            key.nameoffset: 920,
+            key.nameoffset: 895,
             key.namelength: 16,
             key.elements: [
               {
                 key.kind: source.lang.swift.structure.elem.init_expr,
-                key.offset: 939,
+                key.offset: 914,
                 key.length: 2
               }
             ]
@@ -4690,21 +4673,21 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
       },
       {
         key.kind: source.lang.swift.decl.enumcase,
-        key.offset: 947,
+        key.offset: 922,
         key.length: 20,
         key.substructure: [
           {
             key.kind: source.lang.swift.decl.enumelement,
             key.accessibility: source.lang.swift.accessibility.public,
             key.name: "orderedSame",
-            key.offset: 952,
+            key.offset: 927,
             key.length: 15,
-            key.nameoffset: 952,
+            key.nameoffset: 927,
             key.namelength: 11,
             key.elements: [
               {
                 key.kind: source.lang.swift.structure.elem.init_expr,
-                key.offset: 966,
+                key.offset: 941,
                 key.length: 1
               }
             ]
@@ -4713,21 +4696,21 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
       },
       {
         key.kind: source.lang.swift.decl.enumcase,
-        key.offset: 973,
+        key.offset: 948,
         key.length: 26,
         key.substructure: [
           {
             key.kind: source.lang.swift.decl.enumelement,
             key.accessibility: source.lang.swift.accessibility.public,
             key.name: "orderedDescending",
-            key.offset: 978,
+            key.offset: 953,
             key.length: 21,
-            key.nameoffset: 978,
+            key.nameoffset: 953,
             key.namelength: 17,
             key.elements: [
               {
                 key.kind: source.lang.swift.structure.elem.init_expr,
-                key.offset: 998,
+                key.offset: 973,
                 key.length: 1
               }
             ]
@@ -4740,13 +4723,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooRuncingOptions",
-    key.offset: 1045,
+    key.offset: 1020,
     key.length: 197,
-    key.nameoffset: 1052,
+    key.nameoffset: 1027,
     key.namelength: 17,
-    key.bodyoffset: 1083,
+    key.bodyoffset: 1058,
     key.bodylength: 158,
-    key.docoffset: 1003,
+    key.docoffset: 978,
     key.doclength: 35,
     key.inheritedtypes: [
       {
@@ -4755,7 +4738,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 1038,
+        key.offset: 1013,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4763,7 +4746,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 1072,
+        key.offset: 1047,
         key.length: 9
       }
     ],
@@ -4772,13 +4755,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(rawValue:)",
-        key.offset: 1096,
+        key.offset: 1071,
         key.length: 19,
-        key.nameoffset: 1096,
+        key.nameoffset: 1071,
         key.namelength: 19,
         key.attributes: [
           {
-            key.offset: 1089,
+            key.offset: 1064,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4787,10 +4770,10 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "rawValue",
-            key.offset: 1101,
+            key.offset: 1076,
             key.length: 13,
             key.typename: "Int",
-            key.nameoffset: 1101,
+            key.nameoffset: 1076,
             key.namelength: 8
           }
         ]
@@ -4799,16 +4782,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.var.static,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "enableMince",
-        key.offset: 1128,
+        key.offset: 1103,
         key.length: 49,
         key.typename: "FooRuncingOptions",
-        key.nameoffset: 1139,
+        key.nameoffset: 1114,
         key.namelength: 11,
-        key.bodyoffset: 1171,
+        key.bodyoffset: 1146,
         key.bodylength: 5,
         key.attributes: [
           {
-            key.offset: 1121,
+            key.offset: 1096,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4818,16 +4801,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.var.static,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "enableQuince",
-        key.offset: 1190,
+        key.offset: 1165,
         key.length: 50,
         key.typename: "FooRuncingOptions",
-        key.nameoffset: 1201,
+        key.nameoffset: 1176,
         key.namelength: 12,
-        key.bodyoffset: 1234,
+        key.bodyoffset: 1209,
         key.bodylength: 5,
         key.attributes: [
           {
-            key.offset: 1183,
+            key.offset: 1158,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4839,15 +4822,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooStruct1",
-    key.offset: 1251,
+    key.offset: 1226,
     key.length: 129,
-    key.nameoffset: 1258,
+    key.nameoffset: 1233,
     key.namelength: 10,
-    key.bodyoffset: 1270,
+    key.bodyoffset: 1245,
     key.bodylength: 109,
     key.attributes: [
       {
-        key.offset: 1244,
+        key.offset: 1219,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4857,13 +4840,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init()",
-        key.offset: 1283,
+        key.offset: 1258,
         key.length: 6,
-        key.nameoffset: 1283,
+        key.nameoffset: 1258,
         key.namelength: 6,
         key.attributes: [
           {
-            key.offset: 1276,
+            key.offset: 1251,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4873,13 +4856,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(x:y:)",
-        key.offset: 1302,
+        key.offset: 1277,
         key.length: 25,
-        key.nameoffset: 1302,
+        key.nameoffset: 1277,
         key.namelength: 25,
         key.attributes: [
           {
-            key.offset: 1295,
+            key.offset: 1270,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4888,19 +4871,19 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "x",
-            key.offset: 1307,
+            key.offset: 1282,
             key.length: 8,
             key.typename: "Int32",
-            key.nameoffset: 1307,
+            key.nameoffset: 1282,
             key.namelength: 1
           },
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "y",
-            key.offset: 1317,
+            key.offset: 1292,
             key.length: 9,
             key.typename: "Double",
-            key.nameoffset: 1317,
+            key.nameoffset: 1292,
             key.namelength: 1
           }
         ]
@@ -4910,14 +4893,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "x",
-        key.offset: 1340,
+        key.offset: 1315,
         key.length: 12,
         key.typename: "Int32",
-        key.nameoffset: 1344,
+        key.nameoffset: 1319,
         key.namelength: 1,
         key.attributes: [
           {
-            key.offset: 1333,
+            key.offset: 1308,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4928,14 +4911,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "y",
-        key.offset: 1365,
+        key.offset: 1340,
         key.length: 13,
         key.typename: "Double",
-        key.nameoffset: 1369,
+        key.nameoffset: 1344,
         key.namelength: 1,
         key.attributes: [
           {
-            key.offset: 1358,
+            key.offset: 1333,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4947,13 +4930,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.typealias,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooStruct1Pointer",
-    key.offset: 1389,
+    key.offset: 1364,
     key.length: 62,
-    key.nameoffset: 1399,
+    key.nameoffset: 1374,
     key.namelength: 17,
     key.attributes: [
       {
-        key.offset: 1382,
+        key.offset: 1357,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4963,15 +4946,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooStruct2",
-    key.offset: 1460,
+    key.offset: 1435,
     key.length: 129,
-    key.nameoffset: 1467,
+    key.nameoffset: 1442,
     key.namelength: 10,
-    key.bodyoffset: 1479,
+    key.bodyoffset: 1454,
     key.bodylength: 109,
     key.attributes: [
       {
-        key.offset: 1453,
+        key.offset: 1428,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -4981,13 +4964,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init()",
-        key.offset: 1492,
+        key.offset: 1467,
         key.length: 6,
-        key.nameoffset: 1492,
+        key.nameoffset: 1467,
         key.namelength: 6,
         key.attributes: [
           {
-            key.offset: 1485,
+            key.offset: 1460,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -4997,13 +4980,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(x:y:)",
-        key.offset: 1511,
+        key.offset: 1486,
         key.length: 25,
-        key.nameoffset: 1511,
+        key.nameoffset: 1486,
         key.namelength: 25,
         key.attributes: [
           {
-            key.offset: 1504,
+            key.offset: 1479,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -5012,19 +4995,19 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "x",
-            key.offset: 1516,
+            key.offset: 1491,
             key.length: 8,
             key.typename: "Int32",
-            key.nameoffset: 1516,
+            key.nameoffset: 1491,
             key.namelength: 1
           },
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "y",
-            key.offset: 1526,
+            key.offset: 1501,
             key.length: 9,
             key.typename: "Double",
-            key.nameoffset: 1526,
+            key.nameoffset: 1501,
             key.namelength: 1
           }
         ]
@@ -5034,14 +5017,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "x",
-        key.offset: 1549,
+        key.offset: 1524,
         key.length: 12,
         key.typename: "Int32",
-        key.nameoffset: 1553,
+        key.nameoffset: 1528,
         key.namelength: 1,
         key.attributes: [
           {
-            key.offset: 1542,
+            key.offset: 1517,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -5052,14 +5035,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "y",
-        key.offset: 1574,
+        key.offset: 1549,
         key.length: 13,
         key.typename: "Double",
-        key.nameoffset: 1578,
+        key.nameoffset: 1553,
         key.namelength: 1,
         key.attributes: [
           {
-            key.offset: 1567,
+            key.offset: 1542,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -5071,13 +5054,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.typealias,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooStructTypedef1",
-    key.offset: 1598,
+    key.offset: 1573,
     key.length: 40,
-    key.nameoffset: 1608,
+    key.nameoffset: 1583,
     key.namelength: 17,
     key.attributes: [
       {
-        key.offset: 1591,
+        key.offset: 1566,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5087,15 +5070,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooStructTypedef2",
-    key.offset: 1647,
+    key.offset: 1622,
     key.length: 136,
-    key.nameoffset: 1654,
+    key.nameoffset: 1629,
     key.namelength: 17,
-    key.bodyoffset: 1673,
+    key.bodyoffset: 1648,
     key.bodylength: 109,
     key.attributes: [
       {
-        key.offset: 1640,
+        key.offset: 1615,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5105,13 +5088,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init()",
-        key.offset: 1686,
+        key.offset: 1661,
         key.length: 6,
-        key.nameoffset: 1686,
+        key.nameoffset: 1661,
         key.namelength: 6,
         key.attributes: [
           {
-            key.offset: 1679,
+            key.offset: 1654,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -5121,13 +5104,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(x:y:)",
-        key.offset: 1705,
+        key.offset: 1680,
         key.length: 25,
-        key.nameoffset: 1705,
+        key.nameoffset: 1680,
         key.namelength: 25,
         key.attributes: [
           {
-            key.offset: 1698,
+            key.offset: 1673,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -5136,19 +5119,19 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "x",
-            key.offset: 1710,
+            key.offset: 1685,
             key.length: 8,
             key.typename: "Int32",
-            key.nameoffset: 1710,
+            key.nameoffset: 1685,
             key.namelength: 1
           },
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "y",
-            key.offset: 1720,
+            key.offset: 1695,
             key.length: 9,
             key.typename: "Double",
-            key.nameoffset: 1720,
+            key.nameoffset: 1695,
             key.namelength: 1
           }
         ]
@@ -5158,14 +5141,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "x",
-        key.offset: 1743,
+        key.offset: 1718,
         key.length: 12,
         key.typename: "Int32",
-        key.nameoffset: 1747,
+        key.nameoffset: 1722,
         key.namelength: 1,
         key.attributes: [
           {
-            key.offset: 1736,
+            key.offset: 1711,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -5176,14 +5159,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "y",
-        key.offset: 1768,
+        key.offset: 1743,
         key.length: 13,
         key.typename: "Double",
-        key.nameoffset: 1772,
+        key.nameoffset: 1747,
         key.namelength: 1,
         key.attributes: [
           {
-            key.offset: 1761,
+            key.offset: 1736,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -5195,15 +5178,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.typealias,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooTypedef1",
-    key.offset: 1821,
+    key.offset: 1796,
     key.length: 29,
-    key.nameoffset: 1831,
+    key.nameoffset: 1806,
     key.namelength: 11,
-    key.docoffset: 1785,
+    key.docoffset: 1760,
     key.doclength: 29,
     key.attributes: [
       {
-        key.offset: 1814,
+        key.offset: 1789,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5214,16 +5197,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.accessibility: source.lang.swift.accessibility.public,
     key.setter_accessibility: source.lang.swift.accessibility.public,
     key.name: "fooIntVar",
-    key.offset: 1886,
+    key.offset: 1861,
     key.length: 20,
     key.typename: "Int32",
-    key.nameoffset: 1890,
+    key.nameoffset: 1865,
     key.namelength: 9,
-    key.docoffset: 1852,
+    key.docoffset: 1827,
     key.doclength: 27,
     key.attributes: [
       {
-        key.offset: 1879,
+        key.offset: 1854,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5233,16 +5216,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFunc1(_:)",
-    key.offset: 1941,
+    key.offset: 1916,
     key.length: 34,
     key.typename: "Int32",
-    key.nameoffset: 1946,
+    key.nameoffset: 1921,
     key.namelength: 20,
-    key.docoffset: 1908,
+    key.docoffset: 1883,
     key.doclength: 26,
     key.attributes: [
       {
-        key.offset: 1934,
+        key.offset: 1909,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5251,7 +5234,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "a",
-        key.offset: 1955,
+        key.offset: 1930,
         key.length: 10,
         key.typename: "Int32"
       }
@@ -5261,14 +5244,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFunc1AnonymousParam(_:)",
-    key.offset: 1984,
+    key.offset: 1959,
     key.length: 46,
     key.typename: "Int32",
-    key.nameoffset: 1989,
+    key.nameoffset: 1964,
     key.namelength: 32,
     key.attributes: [
       {
-        key.offset: 1977,
+        key.offset: 1952,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5276,7 +5259,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.substructure: [
       {
         key.kind: source.lang.swift.decl.var.parameter,
-        key.offset: 2012,
+        key.offset: 1987,
         key.length: 8,
         key.typename: "Int32"
       }
@@ -5286,14 +5269,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFunc3(_:_:_:_:)",
-    key.offset: 2039,
+    key.offset: 2014,
     key.length: 94,
     key.typename: "Int32",
-    key.nameoffset: 2044,
+    key.nameoffset: 2019,
     key.namelength: 80,
     key.attributes: [
       {
-        key.offset: 2032,
+        key.offset: 2007,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5302,28 +5285,28 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "a",
-        key.offset: 2053,
+        key.offset: 2028,
         key.length: 10,
         key.typename: "Int32"
       },
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "b",
-        key.offset: 2065,
+        key.offset: 2040,
         key.length: 10,
         key.typename: "Float"
       },
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "c",
-        key.offset: 2077,
+        key.offset: 2052,
         key.length: 11,
         key.typename: "Double"
       },
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "d",
-        key.offset: 2090,
+        key.offset: 2065,
         key.length: 33,
         key.typename: "UnsafeMutablePointer<Int32>!"
       }
@@ -5333,13 +5316,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFuncWithBlock(_:)",
-    key.offset: 2142,
+    key.offset: 2117,
     key.length: 49,
-    key.nameoffset: 2147,
+    key.nameoffset: 2122,
     key.namelength: 44,
     key.attributes: [
       {
-        key.offset: 2135,
+        key.offset: 2110,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5348,7 +5331,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "blk",
-        key.offset: 2164,
+        key.offset: 2139,
         key.length: 26,
         key.typename: "((Float) -> Int32)!"
       }
@@ -5358,13 +5341,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFuncWithFunctionPointer(_:)",
-    key.offset: 2200,
+    key.offset: 2175,
     key.length: 75,
-    key.nameoffset: 2205,
+    key.nameoffset: 2180,
     key.namelength: 70,
     key.attributes: [
       {
-        key.offset: 2193,
+        key.offset: 2168,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5373,7 +5356,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "fptr",
-        key.offset: 2232,
+        key.offset: 2207,
         key.length: 42,
         key.typename: "(@convention(c) (Float) -> Int32)!"
       }
@@ -5383,14 +5366,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFuncNoreturn1()",
-    key.offset: 2284,
+    key.offset: 2259,
     key.length: 32,
     key.typename: "Never",
-    key.nameoffset: 2289,
+    key.nameoffset: 2264,
     key.namelength: 18,
     key.attributes: [
       {
-        key.offset: 2277,
+        key.offset: 2252,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5400,14 +5383,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFuncNoreturn2()",
-    key.offset: 2325,
+    key.offset: 2300,
     key.length: 32,
     key.typename: "Never",
-    key.nameoffset: 2330,
+    key.nameoffset: 2305,
     key.namelength: 18,
     key.attributes: [
       {
-        key.offset: 2318,
+        key.offset: 2293,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5417,15 +5400,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFuncWithComment1()",
-    key.offset: 2429,
+    key.offset: 2404,
     key.length: 26,
-    key.nameoffset: 2434,
+    key.nameoffset: 2409,
     key.namelength: 21,
-    key.docoffset: 2359,
+    key.docoffset: 2334,
     key.doclength: 62,
     key.attributes: [
       {
-        key.offset: 2422,
+        key.offset: 2397,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5435,15 +5418,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFuncWithComment2()",
-    key.offset: 2507,
+    key.offset: 2482,
     key.length: 26,
-    key.nameoffset: 2512,
+    key.nameoffset: 2487,
     key.namelength: 21,
-    key.docoffset: 2457,
+    key.docoffset: 2432,
     key.doclength: 42,
     key.attributes: [
       {
-        key.offset: 2500,
+        key.offset: 2475,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5453,15 +5436,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFuncWithComment3()",
-    key.offset: 2602,
+    key.offset: 2577,
     key.length: 26,
-    key.nameoffset: 2607,
+    key.nameoffset: 2582,
     key.namelength: 21,
-    key.docoffset: 2535,
+    key.docoffset: 2510,
     key.doclength: 59,
     key.attributes: [
       {
-        key.offset: 2595,
+        key.offset: 2570,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5471,15 +5454,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFuncWithComment4()",
-    key.offset: 2690,
+    key.offset: 2665,
     key.length: 26,
-    key.nameoffset: 2695,
+    key.nameoffset: 2670,
     key.namelength: 21,
-    key.docoffset: 2630,
+    key.docoffset: 2605,
     key.doclength: 53,
     key.attributes: [
       {
-        key.offset: 2683,
+        key.offset: 2658,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5489,15 +5472,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooFuncWithComment5()",
-    key.offset: 2784,
+    key.offset: 2759,
     key.length: 26,
-    key.nameoffset: 2789,
+    key.nameoffset: 2764,
     key.namelength: 21,
-    key.docoffset: 2718,
+    key.docoffset: 2693,
     key.doclength: 59,
     key.attributes: [
       {
-        key.offset: 2777,
+        key.offset: 2752,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5507,16 +5490,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "redeclaredInMultipleModulesFunc1(_:)",
-    key.offset: 2869,
+    key.offset: 2844,
     key.length: 58,
     key.typename: "Int32",
-    key.nameoffset: 2874,
+    key.nameoffset: 2849,
     key.namelength: 44,
-    key.docoffset: 2812,
+    key.docoffset: 2787,
     key.doclength: 50,
     key.attributes: [
       {
-        key.offset: 2862,
+        key.offset: 2837,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5525,7 +5508,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "a",
-        key.offset: 2907,
+        key.offset: 2882,
         key.length: 10,
         key.typename: "Int32"
       }
@@ -5535,17 +5518,17 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.protocol,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooProtocolBase",
-    key.offset: 2969,
+    key.offset: 2944,
     key.length: 498,
-    key.nameoffset: 2978,
+    key.nameoffset: 2953,
     key.namelength: 15,
-    key.bodyoffset: 2995,
+    key.bodyoffset: 2970,
     key.bodylength: 471,
-    key.docoffset: 2929,
+    key.docoffset: 2904,
     key.doclength: 33,
     key.attributes: [
       {
-        key.offset: 2962,
+        key.offset: 2937,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5555,42 +5538,42 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "fooProtoFunc()",
-        key.offset: 3048,
+        key.offset: 3023,
         key.length: 19,
-        key.nameoffset: 3053,
+        key.nameoffset: 3028,
         key.namelength: 14,
-        key.docoffset: 3001,
+        key.docoffset: 2976,
         key.doclength: 43
       },
       {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "fooProtoFuncWithExtraIndentation1()",
-        key.offset: 3141,
+        key.offset: 3116,
         key.length: 40,
-        key.nameoffset: 3146,
+        key.nameoffset: 3121,
         key.namelength: 35,
-        key.docoffset: 3073,
+        key.docoffset: 3048,
         key.doclength: 64
       },
       {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "fooProtoFuncWithExtraIndentation2()",
-        key.offset: 3269,
+        key.offset: 3244,
         key.length: 40,
-        key.nameoffset: 3274,
+        key.nameoffset: 3249,
         key.namelength: 35,
-        key.docoffset: 3187,
+        key.docoffset: 3162,
         key.doclength: 77
       },
       {
         key.kind: source.lang.swift.decl.function.method.static,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "fooProtoClassFunc()",
-        key.offset: 3315,
+        key.offset: 3290,
         key.length: 31,
-        key.nameoffset: 3327,
+        key.nameoffset: 3302,
         key.namelength: 19
       },
       {
@@ -5598,12 +5581,12 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "fooProperty1",
-        key.offset: 3352,
+        key.offset: 3327,
         key.length: 35,
         key.typename: "Int32",
-        key.nameoffset: 3356,
+        key.nameoffset: 3331,
         key.namelength: 12,
-        key.bodyoffset: 3377,
+        key.bodyoffset: 3352,
         key.bodylength: 9
       },
       {
@@ -5611,24 +5594,24 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "fooProperty2",
-        key.offset: 3393,
+        key.offset: 3368,
         key.length: 35,
         key.typename: "Int32",
-        key.nameoffset: 3397,
+        key.nameoffset: 3372,
         key.namelength: 12,
-        key.bodyoffset: 3418,
+        key.bodyoffset: 3393,
         key.bodylength: 9
       },
       {
         key.kind: source.lang.swift.decl.var.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "fooProperty3",
-        key.offset: 3434,
+        key.offset: 3409,
         key.length: 31,
         key.typename: "Int32",
-        key.nameoffset: 3438,
+        key.nameoffset: 3413,
         key.namelength: 12,
-        key.bodyoffset: 3459,
+        key.bodyoffset: 3434,
         key.bodylength: 5
       }
     ]
@@ -5637,11 +5620,11 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.protocol,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooProtocolDerived",
-    key.offset: 3476,
+    key.offset: 3451,
     key.length: 49,
-    key.nameoffset: 3485,
+    key.nameoffset: 3460,
     key.namelength: 18,
-    key.bodyoffset: 3523,
+    key.bodyoffset: 3498,
     key.bodylength: 1,
     key.inheritedtypes: [
       {
@@ -5650,7 +5633,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 3469,
+        key.offset: 3444,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -5658,7 +5641,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 3506,
+        key.offset: 3481,
         key.length: 15
       }
     ]
@@ -5667,15 +5650,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.open,
     key.name: "FooClassBase",
-    key.offset: 3532,
+    key.offset: 3507,
     key.length: 285,
-    key.nameoffset: 3538,
+    key.nameoffset: 3513,
     key.namelength: 12,
-    key.bodyoffset: 3552,
+    key.bodyoffset: 3527,
     key.bodylength: 264,
     key.attributes: [
       {
-        key.offset: 3527,
+        key.offset: 3502,
         key.length: 4,
         key.attribute: source.decl.attribute.open
       }
@@ -5685,13 +5668,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooBaseInstanceFunc0()",
-        key.offset: 3563,
+        key.offset: 3538,
         key.length: 27,
-        key.nameoffset: 3568,
+        key.nameoffset: 3543,
         key.namelength: 22,
         key.attributes: [
           {
-            key.offset: 3558,
+            key.offset: 3533,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5701,14 +5684,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooBaseInstanceFunc1(_:)",
-        key.offset: 3601,
+        key.offset: 3576,
         key.length: 60,
         key.typename: "FooClassBase!",
-        key.nameoffset: 3606,
+        key.nameoffset: 3581,
         key.namelength: 38,
         key.attributes: [
           {
-            key.offset: 3596,
+            key.offset: 3571,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5717,7 +5700,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "anObject",
-            key.offset: 3627,
+            key.offset: 3602,
             key.length: 16,
             key.typename: "Any!"
           }
@@ -5727,13 +5710,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init()",
-        key.offset: 3674,
+        key.offset: 3649,
         key.length: 7,
-        key.nameoffset: 3674,
+        key.nameoffset: 3649,
         key.namelength: 7,
         key.attributes: [
           {
-            key.offset: 3667,
+            key.offset: 3642,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -5743,18 +5726,18 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(float:)",
-        key.offset: 3706,
+        key.offset: 3681,
         key.length: 21,
-        key.nameoffset: 3706,
+        key.nameoffset: 3681,
         key.namelength: 21,
         key.attributes: [
           {
-            key.offset: 3694,
+            key.offset: 3669,
             key.length: 11,
             key.attribute: source.decl.attribute.convenience
           },
           {
-            key.offset: 3687,
+            key.offset: 3662,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -5763,10 +5746,10 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "f",
-            key.offset: 3712,
+            key.offset: 3687,
             key.length: 14,
             key.typename: "Float",
-            key.nameoffset: 3712,
+            key.nameoffset: 3687,
             key.namelength: 5
           }
         ]
@@ -5775,13 +5758,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooBaseInstanceFuncOverridden()",
-        key.offset: 3738,
+        key.offset: 3713,
         key.length: 36,
-        key.nameoffset: 3743,
+        key.nameoffset: 3718,
         key.namelength: 31,
         key.attributes: [
           {
-            key.offset: 3733,
+            key.offset: 3708,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5791,13 +5774,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.class,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooBaseClassFunc0()",
-        key.offset: 3785,
+        key.offset: 3760,
         key.length: 30,
-        key.nameoffset: 3796,
+        key.nameoffset: 3771,
         key.namelength: 19,
         key.attributes: [
           {
-            key.offset: 3780,
+            key.offset: 3755,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5809,13 +5792,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.open,
     key.name: "FooClassDerived",
-    key.offset: 3857,
+    key.offset: 3832,
     key.length: 392,
-    key.nameoffset: 3863,
+    key.nameoffset: 3838,
     key.namelength: 15,
-    key.bodyoffset: 3915,
+    key.bodyoffset: 3890,
     key.bodylength: 333,
-    key.docoffset: 3819,
+    key.docoffset: 3794,
     key.doclength: 33,
     key.inheritedtypes: [
       {
@@ -5827,7 +5810,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 3852,
+        key.offset: 3827,
         key.length: 4,
         key.attribute: source.decl.attribute.open
       }
@@ -5835,12 +5818,12 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 3881,
+        key.offset: 3856,
         key.length: 12
       },
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 3895,
+        key.offset: 3870,
         key.length: 18
       }
     ],
@@ -5850,14 +5833,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.open,
         key.setter_accessibility: source.lang.swift.accessibility.open,
         key.name: "fooProperty1",
-        key.offset: 3926,
+        key.offset: 3901,
         key.length: 23,
         key.typename: "Int32",
-        key.nameoffset: 3930,
+        key.nameoffset: 3905,
         key.namelength: 12,
         key.attributes: [
           {
-            key.offset: 3921,
+            key.offset: 3896,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5868,14 +5851,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.open,
         key.setter_accessibility: source.lang.swift.accessibility.open,
         key.name: "fooProperty2",
-        key.offset: 3960,
+        key.offset: 3935,
         key.length: 23,
         key.typename: "Int32",
-        key.nameoffset: 3964,
+        key.nameoffset: 3939,
         key.namelength: 12,
         key.attributes: [
           {
-            key.offset: 3955,
+            key.offset: 3930,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5885,16 +5868,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.var.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooProperty3",
-        key.offset: 3994,
+        key.offset: 3969,
         key.length: 31,
         key.typename: "Int32",
-        key.nameoffset: 3998,
+        key.nameoffset: 3973,
         key.namelength: 12,
-        key.bodyoffset: 4019,
+        key.bodyoffset: 3994,
         key.bodylength: 5,
         key.attributes: [
           {
-            key.offset: 3989,
+            key.offset: 3964,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5904,13 +5887,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooInstanceFunc0()",
-        key.offset: 4036,
+        key.offset: 4011,
         key.length: 23,
-        key.nameoffset: 4041,
+        key.nameoffset: 4016,
         key.namelength: 18,
         key.attributes: [
           {
-            key.offset: 4031,
+            key.offset: 4006,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5920,13 +5903,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooInstanceFunc1(_:)",
-        key.offset: 4070,
+        key.offset: 4045,
         key.length: 33,
-        key.nameoffset: 4075,
+        key.nameoffset: 4050,
         key.namelength: 28,
         key.attributes: [
           {
-            key.offset: 4065,
+            key.offset: 4040,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5935,7 +5918,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "a",
-            key.offset: 4092,
+            key.offset: 4067,
             key.length: 10,
             key.typename: "Int32"
           }
@@ -5945,13 +5928,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooInstanceFunc2(_:withB:)",
-        key.offset: 4114,
+        key.offset: 4089,
         key.length: 49,
-        key.nameoffset: 4119,
+        key.nameoffset: 4094,
         key.namelength: 44,
         key.attributes: [
           {
-            key.offset: 4109,
+            key.offset: 4084,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5960,17 +5943,17 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "a",
-            key.offset: 4136,
+            key.offset: 4111,
             key.length: 10,
             key.typename: "Int32"
           },
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "b",
-            key.offset: 4148,
+            key.offset: 4123,
             key.length: 14,
             key.typename: "Int32",
-            key.nameoffset: 4148,
+            key.nameoffset: 4123,
             key.namelength: 5
           }
         ]
@@ -5979,13 +5962,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooBaseInstanceFuncOverridden()",
-        key.offset: 4174,
+        key.offset: 4149,
         key.length: 36,
-        key.nameoffset: 4179,
+        key.nameoffset: 4154,
         key.namelength: 31,
         key.attributes: [
           {
-            key.offset: 4169,
+            key.offset: 4144,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -5995,13 +5978,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.class,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "fooClassFunc0()",
-        key.offset: 4221,
+        key.offset: 4196,
         key.length: 26,
-        key.nameoffset: 4232,
+        key.nameoffset: 4207,
         key.namelength: 15,
         key.attributes: [
           {
-            key.offset: 4216,
+            key.offset: 4191,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -6013,13 +5996,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.typealias,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "typedef_int_t",
-    key.offset: 4258,
+    key.offset: 4233,
     key.length: 31,
-    key.nameoffset: 4268,
+    key.nameoffset: 4243,
     key.namelength: 13,
     key.attributes: [
       {
-        key.offset: 4251,
+        key.offset: 4226,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6029,16 +6012,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_1",
-    key.offset: 4298,
+    key.offset: 4273,
     key.length: 30,
     key.typename: "Int32",
-    key.nameoffset: 4302,
+    key.nameoffset: 4277,
     key.namelength: 11,
-    key.bodyoffset: 4322,
+    key.bodyoffset: 4297,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4291,
+        key.offset: 4266,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6048,16 +6031,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_2",
-    key.offset: 4337,
+    key.offset: 4312,
     key.length: 30,
     key.typename: "Int32",
-    key.nameoffset: 4341,
+    key.nameoffset: 4316,
     key.namelength: 11,
-    key.bodyoffset: 4361,
+    key.bodyoffset: 4336,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4330,
+        key.offset: 4305,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6067,16 +6050,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_3",
-    key.offset: 4376,
+    key.offset: 4351,
     key.length: 30,
     key.typename: "Int32",
-    key.nameoffset: 4380,
+    key.nameoffset: 4355,
     key.namelength: 11,
-    key.bodyoffset: 4400,
+    key.bodyoffset: 4375,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4369,
+        key.offset: 4344,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6086,16 +6069,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_4",
-    key.offset: 4415,
+    key.offset: 4390,
     key.length: 31,
     key.typename: "UInt32",
-    key.nameoffset: 4419,
+    key.nameoffset: 4394,
     key.namelength: 11,
-    key.bodyoffset: 4440,
+    key.bodyoffset: 4415,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4408,
+        key.offset: 4383,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6105,16 +6088,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_5",
-    key.offset: 4455,
+    key.offset: 4430,
     key.length: 31,
     key.typename: "UInt64",
-    key.nameoffset: 4459,
+    key.nameoffset: 4434,
     key.namelength: 11,
-    key.bodyoffset: 4480,
+    key.bodyoffset: 4455,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4448,
+        key.offset: 4423,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6124,16 +6107,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_6",
-    key.offset: 4495,
+    key.offset: 4470,
     key.length: 38,
     key.typename: "typedef_int_t",
-    key.nameoffset: 4499,
+    key.nameoffset: 4474,
     key.namelength: 11,
-    key.bodyoffset: 4527,
+    key.bodyoffset: 4502,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4488,
+        key.offset: 4463,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6143,16 +6126,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_7",
-    key.offset: 4542,
+    key.offset: 4517,
     key.length: 38,
     key.typename: "typedef_int_t",
-    key.nameoffset: 4546,
+    key.nameoffset: 4521,
     key.namelength: 11,
-    key.bodyoffset: 4574,
+    key.bodyoffset: 4549,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4535,
+        key.offset: 4510,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6162,16 +6145,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_8",
-    key.offset: 4589,
+    key.offset: 4564,
     key.length: 30,
     key.typename: "CChar",
-    key.nameoffset: 4593,
+    key.nameoffset: 4568,
     key.namelength: 11,
-    key.bodyoffset: 4613,
+    key.bodyoffset: 4588,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4582,
+        key.offset: 4557,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6181,16 +6164,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_9",
-    key.offset: 4628,
+    key.offset: 4603,
     key.length: 30,
     key.typename: "Int32",
-    key.nameoffset: 4632,
+    key.nameoffset: 4607,
     key.namelength: 11,
-    key.bodyoffset: 4652,
+    key.bodyoffset: 4627,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4621,
+        key.offset: 4596,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6200,16 +6183,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_10",
-    key.offset: 4667,
+    key.offset: 4642,
     key.length: 31,
     key.typename: "Int16",
-    key.nameoffset: 4671,
+    key.nameoffset: 4646,
     key.namelength: 12,
-    key.bodyoffset: 4692,
+    key.bodyoffset: 4667,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4660,
+        key.offset: 4635,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6219,16 +6202,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_11",
-    key.offset: 4707,
+    key.offset: 4682,
     key.length: 29,
     key.typename: "Int",
-    key.nameoffset: 4711,
+    key.nameoffset: 4686,
     key.namelength: 12,
-    key.bodyoffset: 4730,
+    key.bodyoffset: 4705,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4700,
+        key.offset: 4675,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6238,16 +6221,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_OR",
-    key.offset: 4745,
+    key.offset: 4720,
     key.length: 31,
     key.typename: "Int32",
-    key.nameoffset: 4749,
+    key.nameoffset: 4724,
     key.namelength: 12,
-    key.bodyoffset: 4770,
+    key.bodyoffset: 4745,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4738,
+        key.offset: 4713,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6257,16 +6240,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_AND",
-    key.offset: 4785,
+    key.offset: 4760,
     key.length: 32,
     key.typename: "Int32",
-    key.nameoffset: 4789,
+    key.nameoffset: 4764,
     key.namelength: 13,
-    key.bodyoffset: 4811,
+    key.bodyoffset: 4786,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4778,
+        key.offset: 4753,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6276,16 +6259,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_BITWIDTH",
-    key.offset: 4826,
+    key.offset: 4801,
     key.length: 38,
     key.typename: "UInt64",
-    key.nameoffset: 4830,
+    key.nameoffset: 4805,
     key.namelength: 18,
-    key.bodyoffset: 4858,
+    key.bodyoffset: 4833,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4819,
+        key.offset: 4794,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6295,16 +6278,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_SIGNED",
-    key.offset: 4873,
+    key.offset: 4848,
     key.length: 36,
     key.typename: "UInt32",
-    key.nameoffset: 4877,
+    key.nameoffset: 4852,
     key.namelength: 16,
-    key.bodyoffset: 4903,
+    key.bodyoffset: 4878,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4866,
+        key.offset: 4841,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6314,16 +6297,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_REDEF_1",
-    key.offset: 4918,
+    key.offset: 4893,
     key.length: 36,
     key.typename: "Int32",
-    key.nameoffset: 4922,
+    key.nameoffset: 4897,
     key.namelength: 17,
-    key.bodyoffset: 4948,
+    key.bodyoffset: 4923,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4911,
+        key.offset: 4886,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6333,16 +6316,16 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FOO_MACRO_REDEF_2",
-    key.offset: 4963,
+    key.offset: 4938,
     key.length: 36,
     key.typename: "Int32",
-    key.nameoffset: 4967,
+    key.nameoffset: 4942,
     key.namelength: 17,
-    key.bodyoffset: 4993,
+    key.bodyoffset: 4968,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 4956,
+        key.offset: 4931,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6352,13 +6335,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "theLastDeclInFoo()",
-    key.offset: 5008,
+    key.offset: 4983,
     key.length: 23,
-    key.nameoffset: 5013,
+    key.nameoffset: 4988,
     key.namelength: 18,
     key.attributes: [
       {
-        key.offset: 5001,
+        key.offset: 4976,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6368,13 +6351,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "_internalTopLevelFunc()",
-    key.offset: 5040,
+    key.offset: 5015,
     key.length: 28,
-    key.nameoffset: 5045,
+    key.nameoffset: 5020,
     key.namelength: 23,
     key.attributes: [
       {
-        key.offset: 5033,
+        key.offset: 5008,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6384,15 +6367,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "_InternalStruct",
-    key.offset: 5077,
+    key.offset: 5052,
     key.length: 97,
-    key.nameoffset: 5084,
+    key.nameoffset: 5059,
     key.namelength: 15,
-    key.bodyoffset: 5101,
+    key.bodyoffset: 5076,
     key.bodylength: 72,
     key.attributes: [
       {
-        key.offset: 5070,
+        key.offset: 5045,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6402,13 +6385,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init()",
-        key.offset: 5114,
+        key.offset: 5089,
         key.length: 6,
-        key.nameoffset: 5114,
+        key.nameoffset: 5089,
         key.namelength: 6,
         key.attributes: [
           {
-            key.offset: 5107,
+            key.offset: 5082,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -6418,13 +6401,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(x:)",
-        key.offset: 5133,
+        key.offset: 5108,
         key.length: 14,
-        key.nameoffset: 5133,
+        key.nameoffset: 5108,
         key.namelength: 14,
         key.attributes: [
           {
-            key.offset: 5126,
+            key.offset: 5101,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -6433,10 +6416,10 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "x",
-            key.offset: 5138,
+            key.offset: 5113,
             key.length: 8,
             key.typename: "Int32",
-            key.nameoffset: 5138,
+            key.nameoffset: 5113,
             key.namelength: 1
           }
         ]
@@ -6446,14 +6429,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "x",
-        key.offset: 5160,
+        key.offset: 5135,
         key.length: 12,
         key.typename: "Int32",
-        key.nameoffset: 5164,
+        key.nameoffset: 5139,
         key.namelength: 1,
         key.attributes: [
           {
-            key.offset: 5153,
+            key.offset: 5128,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -6464,25 +6447,25 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
   {
     key.kind: source.lang.swift.decl.extension,
     key.name: "FooClassBase",
-    key.offset: 5176,
+    key.offset: 5151,
     key.length: 66,
-    key.nameoffset: 5186,
+    key.nameoffset: 5161,
     key.namelength: 12,
-    key.bodyoffset: 5200,
+    key.bodyoffset: 5175,
     key.bodylength: 41,
     key.substructure: [
       {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "_internalMeth1()",
-        key.offset: 5211,
+        key.offset: 5186,
         key.length: 29,
         key.typename: "Any!",
-        key.nameoffset: 5216,
+        key.nameoffset: 5191,
         key.namelength: 16,
         key.attributes: [
           {
-            key.offset: 5206,
+            key.offset: 5181,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -6493,25 +6476,25 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
   {
     key.kind: source.lang.swift.decl.extension,
     key.name: "FooClassBase",
-    key.offset: 5244,
+    key.offset: 5219,
     key.length: 107,
-    key.nameoffset: 5254,
+    key.nameoffset: 5229,
     key.namelength: 12,
-    key.bodyoffset: 5268,
+    key.bodyoffset: 5243,
     key.bodylength: 82,
     key.substructure: [
       {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "_internalMeth2()",
-        key.offset: 5279,
+        key.offset: 5254,
         key.length: 29,
         key.typename: "Any!",
-        key.nameoffset: 5284,
+        key.nameoffset: 5259,
         key.namelength: 16,
         key.attributes: [
           {
-            key.offset: 5274,
+            key.offset: 5249,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -6521,14 +6504,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "nonInternalMeth()",
-        key.offset: 5319,
+        key.offset: 5294,
         key.length: 30,
         key.typename: "Any!",
-        key.nameoffset: 5324,
+        key.nameoffset: 5299,
         key.namelength: 17,
         key.attributes: [
           {
-            key.offset: 5314,
+            key.offset: 5289,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -6539,25 +6522,25 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
   {
     key.kind: source.lang.swift.decl.extension,
     key.name: "FooClassBase",
-    key.offset: 5353,
+    key.offset: 5328,
     key.length: 66,
-    key.nameoffset: 5363,
+    key.nameoffset: 5338,
     key.namelength: 12,
-    key.bodyoffset: 5377,
+    key.bodyoffset: 5352,
     key.bodylength: 41,
     key.substructure: [
       {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "_internalMeth3()",
-        key.offset: 5388,
+        key.offset: 5363,
         key.length: 29,
         key.typename: "Any!",
-        key.nameoffset: 5393,
+        key.nameoffset: 5368,
         key.namelength: 16,
         key.attributes: [
           {
-            key.offset: 5383,
+            key.offset: 5358,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -6569,15 +6552,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.protocol,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "_InternalProt",
-    key.offset: 5428,
+    key.offset: 5403,
     key.length: 26,
-    key.nameoffset: 5437,
+    key.nameoffset: 5412,
     key.namelength: 13,
-    key.bodyoffset: 5452,
+    key.bodyoffset: 5427,
     key.bodylength: 1,
     key.attributes: [
       {
-        key.offset: 5421,
+        key.offset: 5396,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6587,11 +6570,11 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.open,
     key.name: "ClassWithInternalProt",
-    key.offset: 5461,
+    key.offset: 5436,
     key.length: 47,
-    key.nameoffset: 5467,
+    key.nameoffset: 5442,
     key.namelength: 21,
-    key.bodyoffset: 5506,
+    key.bodyoffset: 5481,
     key.bodylength: 1,
     key.inheritedtypes: [
       {
@@ -6600,7 +6583,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 5456,
+        key.offset: 5431,
         key.length: 4,
         key.attribute: source.decl.attribute.open
       }
@@ -6608,7 +6591,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 5491,
+        key.offset: 5466,
         key.length: 13
       }
     ]
@@ -6617,11 +6600,11 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.open,
     key.name: "FooClassPropertyOwnership",
-    key.offset: 5515,
+    key.offset: 5490,
     key.length: 319,
-    key.nameoffset: 5521,
+    key.nameoffset: 5496,
     key.namelength: 25,
-    key.bodyoffset: 5563,
+    key.bodyoffset: 5538,
     key.bodylength: 270,
     key.inheritedtypes: [
       {
@@ -6630,7 +6613,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 5510,
+        key.offset: 5485,
         key.length: 4,
         key.attribute: source.decl.attribute.open
       }
@@ -6638,7 +6621,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 5549,
+        key.offset: 5524,
         key.length: 12
       }
     ],
@@ -6648,19 +6631,19 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.open,
         key.setter_accessibility: source.lang.swift.accessibility.open,
         key.name: "assignable",
-        key.offset: 5590,
+        key.offset: 5565,
         key.length: 26,
         key.typename: "AnyObject!",
-        key.nameoffset: 5594,
+        key.nameoffset: 5569,
         key.namelength: 10,
         key.attributes: [
           {
-            key.offset: 5585,
+            key.offset: 5560,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           },
           {
-            key.offset: 5569,
+            key.offset: 5544,
             key.length: 15,
             key.attribute: source.decl.attribute.weak
           }
@@ -6671,19 +6654,19 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.open,
         key.setter_accessibility: source.lang.swift.accessibility.open,
         key.name: "unsafeAssignable",
-        key.offset: 5643,
+        key.offset: 5618,
         key.length: 32,
         key.typename: "AnyObject!",
-        key.nameoffset: 5647,
+        key.nameoffset: 5622,
         key.namelength: 16,
         key.attributes: [
           {
-            key.offset: 5638,
+            key.offset: 5613,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           },
           {
-            key.offset: 5622,
+            key.offset: 5597,
             key.length: 15,
             key.attribute: source.decl.attribute.weak
           }
@@ -6694,14 +6677,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.open,
         key.setter_accessibility: source.lang.swift.accessibility.open,
         key.name: "retainable",
-        key.offset: 5686,
+        key.offset: 5661,
         key.length: 20,
         key.typename: "Any!",
-        key.nameoffset: 5690,
+        key.nameoffset: 5665,
         key.namelength: 10,
         key.attributes: [
           {
-            key.offset: 5681,
+            key.offset: 5656,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -6712,14 +6695,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.open,
         key.setter_accessibility: source.lang.swift.accessibility.open,
         key.name: "strongRef",
-        key.offset: 5717,
+        key.offset: 5692,
         key.length: 19,
         key.typename: "Any!",
-        key.nameoffset: 5721,
+        key.nameoffset: 5696,
         key.namelength: 9,
         key.attributes: [
           {
-            key.offset: 5712,
+            key.offset: 5687,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -6730,14 +6713,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.open,
         key.setter_accessibility: source.lang.swift.accessibility.open,
         key.name: "copyable",
-        key.offset: 5747,
+        key.offset: 5722,
         key.length: 18,
         key.typename: "Any!",
-        key.nameoffset: 5751,
+        key.nameoffset: 5726,
         key.namelength: 8,
         key.attributes: [
           {
-            key.offset: 5742,
+            key.offset: 5717,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -6748,19 +6731,19 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.open,
         key.setter_accessibility: source.lang.swift.accessibility.open,
         key.name: "weakRef",
-        key.offset: 5781,
+        key.offset: 5756,
         key.length: 23,
         key.typename: "AnyObject!",
-        key.nameoffset: 5785,
+        key.nameoffset: 5760,
         key.namelength: 7,
         key.attributes: [
           {
-            key.offset: 5776,
+            key.offset: 5751,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           },
           {
-            key.offset: 5771,
+            key.offset: 5746,
             key.length: 4,
             key.attribute: source.decl.attribute.weak
           }
@@ -6771,14 +6754,14 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.accessibility: source.lang.swift.accessibility.open,
         key.setter_accessibility: source.lang.swift.accessibility.open,
         key.name: "scalar",
-        key.offset: 5815,
+        key.offset: 5790,
         key.length: 17,
         key.typename: "Int32",
-        key.nameoffset: 5819,
+        key.nameoffset: 5794,
         key.namelength: 6,
         key.attributes: [
           {
-            key.offset: 5810,
+            key.offset: 5785,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           }
@@ -6790,11 +6773,11 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.open,
     key.name: "FooUnavailableMembers",
-    key.offset: 5841,
+    key.offset: 5816,
     key.length: 329,
-    key.nameoffset: 5847,
+    key.nameoffset: 5822,
     key.namelength: 21,
-    key.bodyoffset: 5885,
+    key.bodyoffset: 5860,
     key.bodylength: 284,
     key.inheritedtypes: [
       {
@@ -6803,7 +6786,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 5836,
+        key.offset: 5811,
         key.length: 4,
         key.attribute: source.decl.attribute.open
       }
@@ -6811,7 +6794,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 5871,
+        key.offset: 5846,
         key.length: 12
       }
     ],
@@ -6820,18 +6803,18 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(int:)",
-        key.offset: 5910,
+        key.offset: 5885,
         key.length: 19,
-        key.nameoffset: 5910,
+        key.nameoffset: 5885,
         key.namelength: 19,
         key.attributes: [
           {
-            key.offset: 5898,
+            key.offset: 5873,
             key.length: 11,
             key.attribute: source.decl.attribute.convenience
           },
           {
-            key.offset: 5891,
+            key.offset: 5866,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -6840,10 +6823,10 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "i",
-            key.offset: 5916,
+            key.offset: 5891,
             key.length: 12,
             key.typename: "Int32",
-            key.nameoffset: 5916,
+            key.nameoffset: 5891,
             key.namelength: 3
           }
         ]
@@ -6852,18 +6835,18 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "deprecated()",
-        key.offset: 5984,
+        key.offset: 5959,
         key.length: 17,
-        key.nameoffset: 5989,
+        key.nameoffset: 5964,
         key.namelength: 12,
         key.attributes: [
           {
-            key.offset: 5979,
+            key.offset: 5954,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           },
           {
-            key.offset: 5935,
+            key.offset: 5910,
             key.length: 39,
             key.attribute: source.decl.attribute.available
           }
@@ -6873,18 +6856,18 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "availabilityIntroduced()",
-        key.offset: 6042,
+        key.offset: 6017,
         key.length: 29,
-        key.nameoffset: 6047,
+        key.nameoffset: 6022,
         key.namelength: 24,
         key.attributes: [
           {
-            key.offset: 6037,
+            key.offset: 6012,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           },
           {
-            key.offset: 6007,
+            key.offset: 5982,
             key.length: 25,
             key.attribute: source.decl.attribute.available
           }
@@ -6894,18 +6877,18 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.open,
         key.name: "availabilityIntroducedMsg()",
-        key.offset: 6136,
+        key.offset: 6111,
         key.length: 32,
-        key.nameoffset: 6141,
+        key.nameoffset: 6116,
         key.namelength: 27,
         key.attributes: [
           {
-            key.offset: 6131,
+            key.offset: 6106,
             key.length: 4,
             key.attribute: source.decl.attribute.open
           },
           {
-            key.offset: 6077,
+            key.offset: 6052,
             key.length: 49,
             key.attribute: source.decl.attribute.available
           }
@@ -6917,15 +6900,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooCFType",
-    key.offset: 6179,
+    key.offset: 6154,
     key.length: 19,
-    key.nameoffset: 6185,
+    key.nameoffset: 6160,
     key.namelength: 9,
-    key.bodyoffset: 6196,
+    key.bodyoffset: 6171,
     key.bodylength: 1,
     key.attributes: [
       {
-        key.offset: 6172,
+        key.offset: 6147,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -6935,11 +6918,11 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.enum,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "ABAuthorizationStatus",
-    key.offset: 6271,
+    key.offset: 6246,
     key.length: 89,
-    key.nameoffset: 6276,
+    key.nameoffset: 6251,
     key.namelength: 21,
-    key.bodyoffset: 6305,
+    key.bodyoffset: 6280,
     key.bodylength: 54,
     key.inheritedtypes: [
       {
@@ -6948,12 +6931,12 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 6264,
+        key.offset: 6239,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       },
       {
-        key.offset: 6200,
+        key.offset: 6175,
         key.length: 63,
         key.attribute: source.decl.attribute.available
       }
@@ -6961,28 +6944,28 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 6300,
+        key.offset: 6275,
         key.length: 3
       }
     ],
     key.substructure: [
       {
         key.kind: source.lang.swift.decl.enumcase,
-        key.offset: 6311,
+        key.offset: 6286,
         key.length: 22,
         key.substructure: [
           {
             key.kind: source.lang.swift.decl.enumelement,
             key.accessibility: source.lang.swift.accessibility.public,
             key.name: "notDetermined",
-            key.offset: 6316,
+            key.offset: 6291,
             key.length: 17,
-            key.nameoffset: 6316,
+            key.nameoffset: 6291,
             key.namelength: 13,
             key.elements: [
               {
                 key.kind: source.lang.swift.structure.elem.init_expr,
-                key.offset: 6332,
+                key.offset: 6307,
                 key.length: 1
               }
             ]
@@ -6991,21 +6974,21 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
       },
       {
         key.kind: source.lang.swift.decl.enumcase,
-        key.offset: 6339,
+        key.offset: 6314,
         key.length: 19,
         key.substructure: [
           {
             key.kind: source.lang.swift.decl.enumelement,
             key.accessibility: source.lang.swift.accessibility.public,
             key.name: "restricted",
-            key.offset: 6344,
+            key.offset: 6319,
             key.length: 14,
-            key.nameoffset: 6344,
+            key.nameoffset: 6319,
             key.namelength: 10,
             key.elements: [
               {
                 key.kind: source.lang.swift.structure.elem.init_expr,
-                key.offset: 6357,
+                key.offset: 6332,
                 key.length: 1
               }
             ]
@@ -7018,15 +7001,15 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooOverlayClassBase",
-    key.offset: 6369,
+    key.offset: 6344,
     key.length: 50,
-    key.nameoffset: 6375,
+    key.nameoffset: 6350,
     key.namelength: 19,
-    key.bodyoffset: 6396,
+    key.bodyoffset: 6371,
     key.bodylength: 22,
     key.attributes: [
       {
-        key.offset: 6362,
+        key.offset: 6337,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -7036,13 +7019,13 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "f()",
-        key.offset: 6409,
+        key.offset: 6384,
         key.length: 8,
-        key.nameoffset: 6414,
+        key.nameoffset: 6389,
         key.namelength: 3,
         key.attributes: [
           {
-            key.offset: 6402,
+            key.offset: 6377,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -7054,11 +7037,11 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooOverlayClassDerived",
-    key.offset: 6428,
+    key.offset: 6403,
     key.length: 88,
-    key.nameoffset: 6434,
+    key.nameoffset: 6409,
     key.namelength: 22,
-    key.bodyoffset: 6484,
+    key.bodyoffset: 6459,
     key.bodylength: 31,
     key.inheritedtypes: [
       {
@@ -7067,7 +7050,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     ],
     key.attributes: [
       {
-        key.offset: 6421,
+        key.offset: 6396,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -7075,7 +7058,7 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 6459,
+        key.offset: 6434,
         key.length: 23
       }
     ],
@@ -7084,18 +7067,18 @@ public class FooOverlayClassDerived : Foo.FooOverlayClassBase {
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "f()",
-        key.offset: 6506,
+        key.offset: 6481,
         key.length: 8,
-        key.nameoffset: 6511,
+        key.nameoffset: 6486,
         key.namelength: 3,
         key.attributes: [
           {
-            key.offset: 6499,
+            key.offset: 6474,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           },
           {
-            key.offset: 6490,
+            key.offset: 6465,
             key.length: 8,
             key.attribute: source.decl.attribute.override
           }
diff --git a/test/SourceKit/InterfaceGen/gen_clang_module.swift.sub.response b/test/SourceKit/InterfaceGen/gen_clang_module.swift.sub.response
index a96f020da080a..be6aad83e56ee 100644
--- a/test/SourceKit/InterfaceGen/gen_clang_module.swift.sub.response
+++ b/test/SourceKit/InterfaceGen/gen_clang_module.swift.sub.response
@@ -1,4 +1,3 @@
-
 public func fooSubFunc1(_ a: Int32) -> Int32
 
 public struct FooSubEnum1 : Hashable, Equatable, RawRepresentable {
@@ -20,272 +19,272 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
 [
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 1,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 8,
+    key.offset: 7,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 13,
+    key.offset: 12,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 25,
+    key.offset: 24,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 27,
+    key.offset: 26,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 30,
+    key.offset: 29,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 40,
+    key.offset: 39,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 47,
+    key.offset: 46,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 54,
+    key.offset: 53,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 61,
+    key.offset: 60,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 75,
+    key.offset: 74,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 85,
+    key.offset: 84,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 96,
+    key.offset: 95,
     key.length: 16
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 120,
+    key.offset: 119,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 127,
+    key.offset: 126,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 132,
+    key.offset: 131,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 134,
+    key.offset: 133,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 144,
+    key.offset: 143,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 157,
+    key.offset: 156,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 164,
+    key.offset: 163,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 169,
+    key.offset: 168,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 179,
+    key.offset: 178,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 192,
+    key.offset: 191,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 199,
+    key.offset: 198,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 203,
+    key.offset: 202,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 213,
+    key.offset: 212,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 223,
+    key.offset: 222,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 230,
+    key.offset: 229,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 234,
+    key.offset: 233,
     key.length: 12
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 248,
+    key.offset: 247,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 262,
+    key.offset: 261,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 269,
+    key.offset: 268,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 276,
+    key.offset: 275,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 280,
+    key.offset: 279,
     key.length: 12
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 294,
+    key.offset: 293,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 308,
+    key.offset: 307,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 315,
+    key.offset: 314,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 322,
+    key.offset: 321,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 326,
+    key.offset: 325,
     key.length: 25
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 353,
+    key.offset: 352,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 359,
+    key.offset: 358,
     key.length: 3
   }
 ]
 [
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 30,
+    key.offset: 29,
     key.length: 5,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 40,
+    key.offset: 39,
     key.length: 5,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.protocol,
-    key.offset: 75,
+    key.offset: 74,
     key.length: 8,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.protocol,
-    key.offset: 85,
+    key.offset: 84,
     key.length: 9,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.protocol,
-    key.offset: 96,
+    key.offset: 95,
     key.length: 16,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 144,
+    key.offset: 143,
     key.length: 6,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 179,
+    key.offset: 178,
     key.length: 6,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 213,
+    key.offset: 212,
     key.length: 6,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 248,
+    key.offset: 247,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 294,
+    key.offset: 293,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 353,
+    key.offset: 352,
     key.length: 3,
     key.is_system: 1
   }
@@ -295,14 +294,14 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fooSubFunc1(_:)",
-    key.offset: 8,
+    key.offset: 7,
     key.length: 37,
     key.typename: "Int32",
-    key.nameoffset: 13,
+    key.nameoffset: 12,
     key.namelength: 23,
     key.attributes: [
       {
-        key.offset: 1,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -311,7 +310,7 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "a",
-        key.offset: 25,
+        key.offset: 24,
         key.length: 10,
         key.typename: "Int32"
       }
@@ -321,11 +320,11 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooSubEnum1",
-    key.offset: 54,
+    key.offset: 53,
     key.length: 167,
-    key.nameoffset: 61,
+    key.nameoffset: 60,
     key.namelength: 11,
-    key.bodyoffset: 114,
+    key.bodyoffset: 113,
     key.bodylength: 106,
     key.inheritedtypes: [
       {
@@ -340,7 +339,7 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
     ],
     key.attributes: [
       {
-        key.offset: 47,
+        key.offset: 46,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -348,17 +347,17 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
     key.elements: [
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 75,
+        key.offset: 74,
         key.length: 8
       },
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 85,
+        key.offset: 84,
         key.length: 9
       },
       {
         key.kind: source.lang.swift.structure.elem.typeref,
-        key.offset: 96,
+        key.offset: 95,
         key.length: 16
       }
     ],
@@ -367,13 +366,13 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(_:)",
-        key.offset: 127,
+        key.offset: 126,
         key.length: 24,
-        key.nameoffset: 127,
+        key.nameoffset: 126,
         key.namelength: 24,
         key.attributes: [
           {
-            key.offset: 120,
+            key.offset: 119,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -382,7 +381,7 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "rawValue",
-            key.offset: 132,
+            key.offset: 131,
             key.length: 18,
             key.typename: "UInt32"
           }
@@ -392,13 +391,13 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(rawValue:)",
-        key.offset: 164,
+        key.offset: 163,
         key.length: 22,
-        key.nameoffset: 164,
+        key.nameoffset: 163,
         key.namelength: 22,
         key.attributes: [
           {
-            key.offset: 157,
+            key.offset: 156,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -407,10 +406,10 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "rawValue",
-            key.offset: 169,
+            key.offset: 168,
             key.length: 16,
             key.typename: "UInt32",
-            key.nameoffset: 169,
+            key.nameoffset: 168,
             key.namelength: 8
           }
         ]
@@ -420,14 +419,14 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
         key.accessibility: source.lang.swift.accessibility.public,
         key.setter_accessibility: source.lang.swift.accessibility.public,
         key.name: "rawValue",
-        key.offset: 199,
+        key.offset: 198,
         key.length: 20,
         key.typename: "UInt32",
-        key.nameoffset: 203,
+        key.nameoffset: 202,
         key.namelength: 8,
         key.attributes: [
           {
-            key.offset: 192,
+            key.offset: 191,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -439,16 +438,16 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooSubEnum1X",
-    key.offset: 230,
+    key.offset: 229,
     key.length: 37,
     key.typename: "FooSubEnum1",
-    key.nameoffset: 234,
+    key.nameoffset: 233,
     key.namelength: 12,
-    key.bodyoffset: 261,
+    key.bodyoffset: 260,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 223,
+        key.offset: 222,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -458,16 +457,16 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooSubEnum1Y",
-    key.offset: 276,
+    key.offset: 275,
     key.length: 37,
     key.typename: "FooSubEnum1",
-    key.nameoffset: 280,
+    key.nameoffset: 279,
     key.namelength: 12,
-    key.bodyoffset: 307,
+    key.bodyoffset: 306,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 269,
+        key.offset: 268,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -477,16 +476,16 @@ public var FooSubUnnamedEnumeratorA1: Int { get }
     key.kind: source.lang.swift.decl.var.global,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "FooSubUnnamedEnumeratorA1",
-    key.offset: 322,
+    key.offset: 321,
     key.length: 42,
     key.typename: "Int",
-    key.nameoffset: 326,
+    key.nameoffset: 325,
     key.namelength: 25,
-    key.bodyoffset: 358,
+    key.bodyoffset: 357,
     key.bodylength: 5,
     key.attributes: [
       {
-        key.offset: 315,
+        key.offset: 314,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
diff --git a/test/SourceKit/InterfaceGen/gen_public_module_name.swift b/test/SourceKit/InterfaceGen/gen_public_module_name.swift
new file mode 100644
index 0000000000000..13a3dac005775
--- /dev/null
+++ b/test/SourceKit/InterfaceGen/gen_public_module_name.swift
@@ -0,0 +1,97 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t --leading-lines
+
+// RUN: %target-swift-frontend %t/common.swift -sdk %t/sdk \
+// RUN:   -module-name Common \
+// RUN:   -emit-module-path %t/sdk/Common.swiftmodule \
+// RUN:   -emit-module-interface-path %t/sdk/Common.swiftinterface \
+// RUN:   -enable-library-evolution -swift-version 6
+
+// RUN: %target-swift-frontend %t/subimpl.swift -sdk %t/sdk -I %t/sdk \
+// RUN:   -module-name SubImpl \
+// RUN:   -emit-module-path %t/sdk/SubImpl.swiftmodule \
+// RUN:   -emit-module-interface-path %t/sdk/SubImpl.swiftinterface \
+// RUN:   -enable-library-evolution -swift-version 6
+//
+// RUN: %target-swift-frontend %t/modimpl.swift -sdk %t/sdk -I %t/sdk \
+// RUN:   -module-name ModImpl \
+// RUN:   -emit-module-path %t/sdk/ModImpl.swiftmodule \
+// RUN:   -emit-module-interface-path %t/sdk/ModImpl.swiftinterface \
+// RUN:   -enable-library-evolution -swift-version 6 \
+// RUN:   -public-module-name PubMod
+
+// RUN: %target-swift-frontend %t/mod.swift -sdk %t/sdk -I %t/sdk \
+// RUN:   -module-name PubMod \
+// RUN:   -emit-module-path %t/sdk/PubMod.swiftmodule \
+// RUN:   -emit-module-interface-path %t/sdk/PubMod.swiftinterface \
+// RUN:   -enable-library-evolution -swift-version 6
+
+// RUN: %sourcekitd-test -req=interface-gen -module PubMod -- -swift-version 6 -sdk %t/sdk -I %t/sdk -target %target-triple &> %t/PubMod.generatedinterface
+// RUN: %FileCheck -input-file=%t/PubMod.generatedinterface -check-prefix INTERFACE %s
+
+// Cursor info on the type of `ModTy.member2`, ie. `ImplTy` (see the generated `PubMod.generatedinterface`)
+// RUN: %sourcekitd-test -req=interface-gen-open -module PubMod -- -swift-version 6 -sdk %t/sdk -I %t/sdk -target %target-triple \
+// RUN:   == -req=cursor -pos=13:24 | %FileCheck %s --check-prefix=INTERFACE-DEF
+// INTERFACE-DEF: ImplTy
+// INTERFACE-DEF: PubMod
+
+
+//--- common.swift
+public struct CommonType {}
+
+
+//--- subimpl.swift
+public struct SubImplTy {}
+
+
+//--- modimpl.swift
+import struct Common.CommonType
+import SubImpl
+
+public struct ImplTy {
+  public let member: SubImplTy
+  public let member2: SubImpl.SubImplTy
+}
+
+public func fromModImpl(arg: ImplTy, arg2: ModImpl.ImplTy) {}
+
+
+//--- mod.swift
+@_exported import ModImpl
+import struct Common.CommonType
+
+public struct ModTy {
+  public let member: ImplTy
+  public let member2: ModImpl.ImplTy
+}
+
+public func fromMod(arg: ModTy, arg2: PubMod.ModTy) {}
+
+// INTERFACE-NOT: import ModImpl
+// INTERFACE: import struct Common.CommonType
+// INTERFACE: import SubImpl
+// INTERFACE-NOT: import
+// INTERFACE: struct ImplTy
+// INTERFACE:   let member: SubImplTy
+// INTERFACE:   let member2: SubImplTy
+// INTERFACE: struct ModTy
+// INTERFACE:   let member: ImplTy
+// INTERFACE:   let member2: ImplTy
+// INTERFACE: func fromMod(arg: ModTy, arg2: ModTy)
+// INTERFACE: func fromModImpl(arg: ImplTy, arg2: ImplTy)
+
+
+//--- use.swift
+import PubMod
+
+func test() {
+  // RUN: %sourcekitd-test -req=cursor -pos=%(line+1):3 %t/use.swift -- -swift-version 6 -sdk %t/sdk -I %t/sdk -target %target-triple %t/use.swift | %FileCheck -check-prefix=MOD %s
+  fromMod()
+  // MOD: fromMod
+  // MOD: PubMod
+
+  // RUN: %sourcekitd-test -req=cursor -pos=%(line+1):3 %t/use.swift -- -swift-version 6 -sdk %t/sdk -I %t/sdk -target %target-triple %t/use.swift | %FileCheck -check-prefix=MODIMPL %s
+  fromModImpl()
+  // MODIMPL: fromModImpl
+  // MODIMPL: PubMod
+}
diff --git a/test/SourceKit/InterfaceGen/gen_swift_module.swift.from_swiftinterface.response b/test/SourceKit/InterfaceGen/gen_swift_module.swift.from_swiftinterface.response
index d24a270fb3bdf..3ad040ac40bf0 100644
--- a/test/SourceKit/InterfaceGen/gen_swift_module.swift.from_swiftinterface.response
+++ b/test/SourceKit/InterfaceGen/gen_swift_module.swift.from_swiftinterface.response
@@ -1,4 +1,3 @@
-
 public class MyClass {
 
     public func pub_method()
@@ -18,104 +17,104 @@ public func pub_function() -> Int
 [
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 1,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 8,
+    key.offset: 7,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 14,
+    key.offset: 13,
     key.length: 7
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 29,
+    key.offset: 28,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 36,
+    key.offset: 35,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 41,
+    key.offset: 40,
     key.length: 10
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 59,
+    key.offset: 58,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 69,
+    key.offset: 68,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 76,
+    key.offset: 75,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 85,
+    key.offset: 84,
     key.length: 7
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 93,
+    key.offset: 92,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 107,
+    key.offset: 106,
     key.length: 14
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 122,
+    key.offset: 121,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 131,
+    key.offset: 130,
     key.length: 18
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 150,
+    key.offset: 149,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 157,
+    key.offset: 156,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 162,
+    key.offset: 161,
     key.length: 12
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 180,
+    key.offset: 179,
     key.length: 3
   }
 ]
 [
   {
     key.kind: source.lang.swift.ref.associatedtype,
-    key.offset: 93,
+    key.offset: 92,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 180,
+    key.offset: 179,
     key.length: 3,
     key.is_system: 1
   }
@@ -125,15 +124,15 @@ public func pub_function() -> Int
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "MyClass",
-    key.offset: 8,
+    key.offset: 7,
     key.length: 59,
-    key.nameoffset: 14,
+    key.nameoffset: 13,
     key.namelength: 7,
-    key.bodyoffset: 23,
+    key.bodyoffset: 22,
     key.bodylength: 43,
     key.attributes: [
       {
-        key.offset: 1,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -143,13 +142,13 @@ public func pub_function() -> Int
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "pub_method()",
-        key.offset: 36,
+        key.offset: 35,
         key.length: 17,
-        key.nameoffset: 41,
+        key.nameoffset: 40,
         key.namelength: 12,
         key.attributes: [
           {
-            key.offset: 29,
+            key.offset: 28,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -161,15 +160,15 @@ public func pub_function() -> Int
     key.kind: source.lang.swift.decl.protocol,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "MyProto",
-    key.offset: 76,
+    key.offset: 75,
     key.length: 53,
-    key.nameoffset: 85,
+    key.nameoffset: 84,
     key.namelength: 7,
-    key.bodyoffset: 101,
+    key.bodyoffset: 100,
     key.bodylength: 27,
     key.attributes: [
       {
-        key.offset: 69,
+        key.offset: 68,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -179,9 +178,9 @@ public func pub_function() -> Int
         key.kind: source.lang.swift.decl.associatedtype,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "Assoc",
-        key.offset: 107,
+        key.offset: 106,
         key.length: 20,
-        key.nameoffset: 122,
+        key.nameoffset: 121,
         key.namelength: 5
       }
     ]
@@ -190,19 +189,19 @@ public func pub_function() -> Int
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "pub_function()",
-    key.offset: 157,
+    key.offset: 156,
     key.length: 26,
     key.typename: "Int",
-    key.nameoffset: 162,
+    key.nameoffset: 161,
     key.namelength: 14,
     key.attributes: [
       {
-        key.offset: 150,
+        key.offset: 149,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       },
       {
-        key.offset: 131,
+        key.offset: 130,
         key.length: 18,
         key.attribute: source.decl.attribute.discardableResult
       }
diff --git a/test/SourceKit/InterfaceGen/gen_swift_module.swift.response b/test/SourceKit/InterfaceGen/gen_swift_module.swift.response
index a953422294b2d..f7e2815d72f0f 100644
--- a/test/SourceKit/InterfaceGen/gen_swift_module.swift.response
+++ b/test/SourceKit/InterfaceGen/gen_swift_module.swift.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 public class MyClass {
 
     public func pub_method()
@@ -15,117 +13,101 @@ public func pub_function() -> Int
 
 
 [
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 26,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 33,
+    key.offset: 7,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 39,
+    key.offset: 13,
     key.length: 7
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 54,
+    key.offset: 28,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 61,
+    key.offset: 35,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 66,
+    key.offset: 40,
     key.length: 10
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 82,
+    key.offset: 56,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 89,
+    key.offset: 63,
     key.length: 8
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 98,
+    key.offset: 72,
     key.length: 7
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 106,
+    key.offset: 80,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 120,
+    key.offset: 94,
     key.length: 14
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 135,
+    key.offset: 109,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 144,
+    key.offset: 118,
     key.length: 18
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 163,
+    key.offset: 137,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 170,
+    key.offset: 144,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 175,
+    key.offset: 149,
     key.length: 12
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 193,
+    key.offset: 167,
     key.length: 3
   }
 ]
 [
-  {
-    key.kind: source.lang.swift.ref.module,
-    key.offset: 7,
-    key.length: 17,
-    key.is_system: 1
-  },
   {
     key.kind: source.lang.swift.ref.associatedtype,
-    key.offset: 106,
+    key.offset: 80,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 193,
+    key.offset: 167,
     key.length: 3,
     key.is_system: 1
   }
@@ -135,15 +117,15 @@ public func pub_function() -> Int
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "MyClass",
-    key.offset: 33,
+    key.offset: 7,
     key.length: 47,
-    key.nameoffset: 39,
+    key.nameoffset: 13,
     key.namelength: 7,
-    key.bodyoffset: 48,
+    key.bodyoffset: 22,
     key.bodylength: 31,
     key.attributes: [
       {
-        key.offset: 26,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -153,13 +135,13 @@ public func pub_function() -> Int
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "pub_method()",
-        key.offset: 61,
+        key.offset: 35,
         key.length: 17,
-        key.nameoffset: 66,
+        key.nameoffset: 40,
         key.namelength: 12,
         key.attributes: [
           {
-            key.offset: 54,
+            key.offset: 28,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -171,15 +153,15 @@ public func pub_function() -> Int
     key.kind: source.lang.swift.decl.protocol,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "MyProto",
-    key.offset: 89,
+    key.offset: 63,
     key.length: 53,
-    key.nameoffset: 98,
+    key.nameoffset: 72,
     key.namelength: 7,
-    key.bodyoffset: 114,
+    key.bodyoffset: 88,
     key.bodylength: 27,
     key.attributes: [
       {
-        key.offset: 82,
+        key.offset: 56,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -189,9 +171,9 @@ public func pub_function() -> Int
         key.kind: source.lang.swift.decl.associatedtype,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "Assoc",
-        key.offset: 120,
+        key.offset: 94,
         key.length: 20,
-        key.nameoffset: 135,
+        key.nameoffset: 109,
         key.namelength: 5
       }
     ]
@@ -200,19 +182,19 @@ public func pub_function() -> Int
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "pub_function()",
-    key.offset: 170,
+    key.offset: 144,
     key.length: 26,
     key.typename: "Int",
-    key.nameoffset: 175,
+    key.nameoffset: 149,
     key.namelength: 14,
     key.attributes: [
       {
-        key.offset: 163,
+        key.offset: 137,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       },
       {
-        key.offset: 144,
+        key.offset: 118,
         key.length: 18,
         key.attribute: source.decl.attribute.discardableResult
       }
diff --git a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift
index cdda11c1ae6c5..6dd042ab36349 100644
--- a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift
+++ b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift
@@ -9,7 +9,7 @@
 // Make sure cursor info within the generated interface of A on one of the
 // decls originally from a cross-import decls shows 'A' as the parent module.
 //
-// RUN: %sourcekitd-test -req=interface-gen-open -module A -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import  -I %S/../Inputs/CrossImport -module-cache-path %t.mod/mcp == -req=cursor -print-raw-response -pos=11:15 -- -I %S/../Inputs/CrossImport -Xfrontend -enable-cross-import-overlays > %t.response
+// RUN: %sourcekitd-test -req=interface-gen-open -module A -- -Xfrontend -disable-implicit-concurrency-module-import -Xfrontend -disable-implicit-string-processing-module-import  -I %S/../Inputs/CrossImport -module-cache-path %t.mod/mcp == -req=cursor -print-raw-response -pos=9:15 -- -I %S/../Inputs/CrossImport -Xfrontend -enable-cross-import-overlays > %t.response
 // RUN: %FileCheck --input-file %t.response %s
 //
 // CHECK: key.name: "From_ABAdditionsType"
diff --git a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift.A.response b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift.A.response
index 47b8904897690..ab9b8051a7d00 100644
--- a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift.A.response
+++ b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift.A.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 public func fromA()
 
 
@@ -27,192 +25,176 @@ public func other(x: A.From_ABAdditionsType)
 
 
 [
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 26,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 33,
+    key.offset: 7,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 38,
+    key.offset: 12,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 48,
+    key.offset: 22,
     key.length: 23
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 51,
+    key.offset: 25,
     key.length: 19
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 72,
+    key.offset: 46,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 79,
+    key.offset: 53,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 82,
+    key.offset: 56,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 121,
+    key.offset: 95,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 128,
+    key.offset: 102,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 135,
+    key.offset: 109,
     key.length: 20
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 161,
+    key.offset: 135,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 200,
+    key.offset: 174,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 207,
+    key.offset: 181,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 212,
+    key.offset: 186,
     key.length: 16
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 233,
+    key.offset: 207,
     key.length: 29
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 236,
+    key.offset: 210,
     key.length: 25
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 263,
+    key.offset: 237,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 270,
+    key.offset: 244,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 273,
+    key.offset: 247,
     key.length: 46
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 319,
+    key.offset: 293,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 326,
+    key.offset: 300,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 331,
+    key.offset: 305,
     key.length: 27
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 362,
+    key.offset: 336,
     key.length: 46
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 408,
+    key.offset: 382,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 415,
+    key.offset: 389,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 420,
+    key.offset: 394,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 426,
+    key.offset: 400,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 429,
+    key.offset: 403,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 431,
+    key.offset: 405,
     key.length: 20
   }
 ]
 [
   {
     key.kind: source.lang.swift.ref.module,
-    key.offset: 7,
-    key.length: 17,
-    key.is_system: 1
-  },
-  {
-    key.kind: source.lang.swift.ref.module,
-    key.offset: 79,
+    key.offset: 53,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.module,
-    key.offset: 270,
+    key.offset: 244,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.module,
-    key.offset: 429,
+    key.offset: 403,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 431,
+    key.offset: 405,
     key.length: 20
   }
 ]
@@ -221,13 +203,13 @@ public func other(x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fromA()",
-    key.offset: 33,
+    key.offset: 7,
     key.length: 12,
-    key.nameoffset: 38,
+    key.nameoffset: 12,
     key.namelength: 7,
     key.attributes: [
       {
-        key.offset: 26,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -237,15 +219,15 @@ public func other(x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "From_ABAdditionsType",
-    key.offset: 128,
+    key.offset: 102,
     key.length: 31,
-    key.nameoffset: 135,
+    key.nameoffset: 109,
     key.namelength: 20,
-    key.bodyoffset: 157,
+    key.bodyoffset: 131,
     key.bodylength: 1,
     key.attributes: [
       {
-        key.offset: 121,
+        key.offset: 95,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -255,13 +237,13 @@ public func other(x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "from_ABAdditions()",
-    key.offset: 207,
+    key.offset: 181,
     key.length: 23,
-    key.nameoffset: 212,
+    key.nameoffset: 186,
     key.namelength: 18,
     key.attributes: [
       {
-        key.offset: 200,
+        key.offset: 174,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -271,13 +253,13 @@ public func other(x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "from__ABAdditionsCAdditions()",
-    key.offset: 326,
+    key.offset: 300,
     key.length: 34,
-    key.nameoffset: 331,
+    key.nameoffset: 305,
     key.namelength: 29,
     key.attributes: [
       {
-        key.offset: 319,
+        key.offset: 293,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -287,13 +269,13 @@ public func other(x: A.From_ABAdditionsType)
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "other(x:)",
-    key.offset: 415,
+    key.offset: 389,
     key.length: 37,
-    key.nameoffset: 420,
+    key.nameoffset: 394,
     key.namelength: 32,
     key.attributes: [
       {
-        key.offset: 408,
+        key.offset: 382,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -302,10 +284,10 @@ public func other(x: A.From_ABAdditionsType)
       {
         key.kind: source.lang.swift.decl.var.parameter,
         key.name: "x",
-        key.offset: 426,
+        key.offset: 400,
         key.length: 25,
         key.typename: "A.From_ABAdditionsType",
-        key.nameoffset: 426,
+        key.nameoffset: 400,
         key.namelength: 1
       }
     ]
diff --git a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift.Other.response b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift.Other.response
index 5e6bb1ecdad4e..d187e53272463 100644
--- a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift.Other.response
+++ b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import.swift.Other.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 public func fromOther()
 
 
@@ -7,7 +5,6 @@ public func fromOther()
 
 import B
 import C
-import A
 
 // Available when C is imported with Other
 /// This has some interesting documentation that shouldn't be separated from
@@ -17,127 +14,96 @@ public func from_OtherCAdditions()
 
 
 [
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 26,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 33,
+    key.offset: 7,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 38,
+    key.offset: 12,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 52,
+    key.offset: 26,
     key.length: 23
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 55,
+    key.offset: 29,
     key.length: 19
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 76,
+    key.offset: 50,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 83,
+    key.offset: 57,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 85,
+    key.offset: 59,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 92,
-    key.length: 1
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 94,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 101,
+    key.offset: 66,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 104,
+    key.offset: 69,
     key.length: 43
   },
   {
     key.kind: source.lang.swift.syntaxtype.doccomment,
-    key.offset: 147,
+    key.offset: 112,
     key.length: 77
   },
   {
     key.kind: source.lang.swift.syntaxtype.doccomment,
-    key.offset: 224,
+    key.offset: 189,
     key.length: 80
   },
   {
     key.kind: source.lang.swift.syntaxtype.doccomment,
-    key.offset: 304,
+    key.offset: 269,
     key.length: 36
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 340,
+    key.offset: 305,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 347,
+    key.offset: 312,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 352,
+    key.offset: 317,
     key.length: 20
   }
 ]
 [
   {
     key.kind: source.lang.swift.ref.module,
-    key.offset: 7,
-    key.length: 17,
-    key.is_system: 1
-  },
-  {
-    key.kind: source.lang.swift.ref.module,
-    key.offset: 83,
+    key.offset: 57,
     key.length: 1
   },
   {
     key.kind: source.lang.swift.ref.module,
-    key.offset: 92,
-    key.length: 1
-  },
-  {
-    key.kind: source.lang.swift.ref.module,
-    key.offset: 101,
+    key.offset: 66,
     key.length: 1
   }
 ]
@@ -146,13 +112,13 @@ public func from_OtherCAdditions()
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fromOther()",
-    key.offset: 33,
+    key.offset: 7,
     key.length: 16,
-    key.nameoffset: 38,
+    key.nameoffset: 12,
     key.namelength: 11,
     key.attributes: [
       {
-        key.offset: 26,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -162,15 +128,15 @@ public func from_OtherCAdditions()
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "from_OtherCAdditions()",
-    key.offset: 347,
+    key.offset: 312,
     key.length: 27,
-    key.nameoffset: 352,
+    key.nameoffset: 317,
     key.namelength: 22,
-    key.docoffset: 147,
+    key.docoffset: 112,
     key.doclength: 193,
     key.attributes: [
       {
-        key.offset: 340,
+        key.offset: 305,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
diff --git a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift
index 21ee8932fd1dd..8ec74eb2fe1cc 100644
--- a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift
+++ b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift
@@ -12,7 +12,7 @@
 // Make sure cursor info within the generated interface of SwiftFramework on one of the
 // decls originally from a cross-import decls shows 'SwiftFramework' as the parent module.
 //
-// RUN: %sourcekitd-test -req=interface-gen-open -module SwiftFramework -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -module-cache-path %t/mcp == -req=cursor -print-raw-response -pos=9:13 -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -Xfrontend -enable-cross-import-overlays > %t.response
+// RUN: %sourcekitd-test -req=interface-gen-open -module SwiftFramework -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -module-cache-path %t/mcp == -req=cursor -print-raw-response -pos=7:13 -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -Xfrontend -enable-cross-import-overlays > %t.response
 // RUN: %FileCheck --input-file %t.response --check-prefix=CHECKSWIFT %s
 //
 // CHECKSWIFT: key.name: "fromSwiftFrameworkCrossImport()"
@@ -27,7 +27,7 @@
 // Make sure cursor info within the generated interface of ClangFramework on one of the
 // decls originally from a cross-import decls shows 'ClangFramework' as the parent module.
 //
-// RUN: %sourcekitd-test -req=interface-gen-open -module ClangFramework -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -module-cache-path %t/mcp == -req=cursor -print-raw-response -pos=10:13 -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -Xfrontend -enable-cross-import-overlays > %t.response
+// RUN: %sourcekitd-test -req=interface-gen-open -module ClangFramework -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -module-cache-path %t/mcp == -req=cursor -print-raw-response -pos=7:13 -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -Xfrontend -enable-cross-import-overlays > %t.response
 // RUN: %FileCheck --input-file %t.response --check-prefix=CHECKCLANG %s
 //
 // CHECKCLANG: key.name: "fromClangFrameworkCrossImport()"
@@ -42,7 +42,7 @@
 // Make sure cursor info within the generated interface of OverlaidClangFramework on one of the
 // decls originally from a cross-import decls shows 'OverlaidClangFramework' as the parent module.
 //
-// RUN: %sourcekitd-test -req=interface-gen-open -module OverlaidClangFramework -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -module-cache-path %t/mcp == -req=cursor -print-raw-response -pos=11:13 -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -Xfrontend -enable-cross-import-overlays > %t.response
+// RUN: %sourcekitd-test -req=interface-gen-open -module OverlaidClangFramework -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -module-cache-path %t/mcp == -req=cursor -print-raw-response -pos=9:13 -- -target %target-triple -I %t/include -I %t/lib/swift -F %t/Frameworks -Xfrontend -enable-cross-import-overlays > %t.response
 // RUN: %FileCheck --input-file %t.response --check-prefix=CHECKOVERLAIDCLANG %s
 //
 // CHECKOVERLAIDCLANG: key.name: "fromOverlaidClangFrameworkCrossImport()"
diff --git a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.ClangFramework.response b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.ClangFramework.response
index 02277acde3047..e328a1534226e 100644
--- a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.ClangFramework.response
+++ b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.ClangFramework.response
@@ -1,11 +1,8 @@
-
 public func fromClangFramework()
 
 
 // MARK: - BystandingLibrary Additions
 
-import SwiftOnoneSupport
-
 // Available when BystandingLibrary is imported with ClangFramework
 public func fromClangFrameworkCrossImport()
 
@@ -13,80 +10,63 @@ public func fromClangFrameworkCrossImport()
 [
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 1,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 8,
+    key.offset: 7,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 13,
+    key.offset: 12,
     key.length: 18
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 36,
+    key.offset: 35,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 39,
+    key.offset: 38,
     key.length: 35
   },
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 76,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 83,
-    key.length: 17
-  },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 102,
+    key.offset: 75,
     key.length: 68
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 170,
+    key.offset: 143,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 177,
+    key.offset: 150,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 182,
+    key.offset: 155,
     key.length: 29
   }
 ]
-[
-  {
-    key.kind: source.lang.swift.ref.module,
-    key.offset: 83,
-    key.length: 17,
-    key.is_system: 1
-  }
-]
+<<NULL>>
 [
   {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fromClangFramework()",
-    key.offset: 8,
+    key.offset: 7,
     key.length: 25,
-    key.nameoffset: 13,
+    key.nameoffset: 12,
     key.namelength: 20,
     key.attributes: [
       {
-        key.offset: 1,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -96,13 +76,13 @@ public func fromClangFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fromClangFrameworkCrossImport()",
-    key.offset: 177,
+    key.offset: 150,
     key.length: 36,
-    key.nameoffset: 182,
+    key.nameoffset: 155,
     key.namelength: 31,
     key.attributes: [
       {
-        key.offset: 170,
+        key.offset: 143,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
diff --git a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.OverlaidClangFramework.response b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.OverlaidClangFramework.response
index c5264e258bec4..a7457cb95b9a5 100644
--- a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.OverlaidClangFramework.response
+++ b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.OverlaidClangFramework.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 public func fromOverlaidClangFramework()
 
 public func fromOverlaidClangFrameworkOverlay()
@@ -12,97 +10,80 @@ public func fromOverlaidClangFrameworkCrossImport()
 
 
 [
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 26,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 33,
+    key.offset: 7,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 38,
+    key.offset: 12,
     key.length: 26
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 68,
+    key.offset: 42,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 75,
+    key.offset: 49,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 80,
+    key.offset: 54,
     key.length: 33
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 118,
+    key.offset: 92,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 121,
+    key.offset: 95,
     key.length: 35
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 158,
+    key.offset: 132,
     key.length: 76
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 234,
+    key.offset: 208,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 241,
+    key.offset: 215,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 246,
+    key.offset: 220,
     key.length: 37
   }
 ]
-[
-  {
-    key.kind: source.lang.swift.ref.module,
-    key.offset: 7,
-    key.length: 17,
-    key.is_system: 1
-  }
-]
+<<NULL>>
 [
   {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fromOverlaidClangFramework()",
-    key.offset: 33,
+    key.offset: 7,
     key.length: 33,
-    key.nameoffset: 38,
+    key.nameoffset: 12,
     key.namelength: 28,
     key.attributes: [
       {
-        key.offset: 26,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -112,13 +93,13 @@ public func fromOverlaidClangFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fromOverlaidClangFrameworkOverlay()",
-    key.offset: 75,
+    key.offset: 49,
     key.length: 40,
-    key.nameoffset: 80,
+    key.nameoffset: 54,
     key.namelength: 35,
     key.attributes: [
       {
-        key.offset: 68,
+        key.offset: 42,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -128,13 +109,13 @@ public func fromOverlaidClangFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fromOverlaidClangFrameworkCrossImport()",
-    key.offset: 241,
+    key.offset: 215,
     key.length: 44,
-    key.nameoffset: 246,
+    key.nameoffset: 220,
     key.namelength: 39,
     key.attributes: [
       {
-        key.offset: 234,
+        key.offset: 208,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
diff --git a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.SwiftFramework.response b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.SwiftFramework.response
index 882119057c93d..9aef8083b4b47 100644
--- a/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.SwiftFramework.response
+++ b/test/SourceKit/InterfaceGen/gen_swift_module_cross_import_common.swift.SwiftFramework.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 public func fromSwiftFramework()
 
 
@@ -10,82 +8,65 @@ public func fromSwiftFrameworkCrossImport()
 
 
 [
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 26,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 33,
+    key.offset: 7,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 38,
+    key.offset: 12,
     key.length: 18
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 61,
+    key.offset: 35,
     key.length: 39
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment.mark,
-    key.offset: 64,
+    key.offset: 38,
     key.length: 35
   },
   {
     key.kind: source.lang.swift.syntaxtype.comment,
-    key.offset: 101,
+    key.offset: 75,
     key.length: 68
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 169,
+    key.offset: 143,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 176,
+    key.offset: 150,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 181,
+    key.offset: 155,
     key.length: 29
   }
 ]
-[
-  {
-    key.kind: source.lang.swift.ref.module,
-    key.offset: 7,
-    key.length: 17,
-    key.is_system: 1
-  }
-]
+<<NULL>>
 [
   {
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fromSwiftFramework()",
-    key.offset: 33,
+    key.offset: 7,
     key.length: 25,
-    key.nameoffset: 38,
+    key.nameoffset: 12,
     key.namelength: 20,
     key.attributes: [
       {
-        key.offset: 26,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -95,13 +76,13 @@ public func fromSwiftFrameworkCrossImport()
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "fromSwiftFrameworkCrossImport()",
-    key.offset: 176,
+    key.offset: 150,
     key.length: 36,
-    key.nameoffset: 181,
+    key.nameoffset: 155,
     key.namelength: 31,
     key.attributes: [
       {
-        key.offset: 169,
+        key.offset: 143,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
diff --git a/test/SourceKit/InterfaceGen/gen_swiftonly_systemmodule.swift.response b/test/SourceKit/InterfaceGen/gen_swiftonly_systemmodule.swift.response
index e254bb11f58a1..302e54eb71954 100644
--- a/test/SourceKit/InterfaceGen/gen_swiftonly_systemmodule.swift.response
+++ b/test/SourceKit/InterfaceGen/gen_swiftonly_systemmodule.swift.response
@@ -1,5 +1,3 @@
-import SwiftOnoneSupport
-
 public class PublicClass {
 }
 
@@ -16,149 +14,133 @@ public func publicFunc()
 
 
 [
-  {
-    key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 0,
-    key.length: 6
-  },
-  {
-    key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 7,
-    key.length: 17
-  },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 26,
+    key.offset: 0,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 33,
+    key.offset: 7,
     key.length: 5
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 39,
+    key.offset: 13,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 56,
+    key.offset: 30,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 63,
+    key.offset: 37,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 70,
+    key.offset: 44,
     key.length: 9
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 87,
+    key.offset: 61,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 94,
+    key.offset: 68,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 98,
+    key.offset: 72,
     key.length: 11
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 111,
+    key.offset: 85,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 117,
+    key.offset: 91,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 128,
+    key.offset: 102,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 135,
+    key.offset: 109,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 140,
+    key.offset: 114,
     key.length: 12
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 158,
+    key.offset: 132,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 167,
+    key.offset: 141,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 174,
+    key.offset: 148,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 179,
+    key.offset: 153,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.typeidentifier,
-    key.offset: 187,
+    key.offset: 161,
     key.length: 3
   },
   {
     key.kind: source.lang.swift.syntaxtype.attribute.builtin,
-    key.offset: 195,
+    key.offset: 169,
     key.length: 6
   },
   {
     key.kind: source.lang.swift.syntaxtype.keyword,
-    key.offset: 202,
+    key.offset: 176,
     key.length: 4
   },
   {
     key.kind: source.lang.swift.syntaxtype.identifier,
-    key.offset: 207,
+    key.offset: 181,
     key.length: 10
   }
 ]
 [
-  {
-    key.kind: source.lang.swift.ref.module,
-    key.offset: 7,
-    key.length: 17,
-    key.is_system: 1
-  },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 111,
+    key.offset: 85,
     key.length: 3,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 158,
+    key.offset: 132,
     key.length: 3,
     key.is_system: 1
   },
   {
     key.kind: source.lang.swift.ref.struct,
-    key.offset: 187,
+    key.offset: 161,
     key.length: 3,
     key.is_system: 1
   }
@@ -168,15 +150,15 @@ public func publicFunc()
     key.kind: source.lang.swift.decl.class,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "PublicClass",
-    key.offset: 33,
+    key.offset: 7,
     key.length: 21,
-    key.nameoffset: 39,
+    key.nameoffset: 13,
     key.namelength: 11,
-    key.bodyoffset: 52,
+    key.bodyoffset: 26,
     key.bodylength: 1,
     key.attributes: [
       {
-        key.offset: 26,
+        key.offset: 0,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -186,15 +168,15 @@ public func publicFunc()
     key.kind: source.lang.swift.decl.struct,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "SomeValue",
-    key.offset: 63,
+    key.offset: 37,
     key.length: 130,
-    key.nameoffset: 70,
+    key.nameoffset: 44,
     key.namelength: 9,
-    key.bodyoffset: 81,
+    key.bodyoffset: 55,
     key.bodylength: 111,
     key.attributes: [
       {
-        key.offset: 56,
+        key.offset: 30,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
@@ -204,16 +186,16 @@ public func publicFunc()
         key.kind: source.lang.swift.decl.var.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "publicValue",
-        key.offset: 94,
+        key.offset: 68,
         key.length: 28,
         key.typename: "Int",
-        key.nameoffset: 98,
+        key.nameoffset: 72,
         key.namelength: 11,
-        key.bodyoffset: 116,
+        key.bodyoffset: 90,
         key.bodylength: 5,
         key.attributes: [
           {
-            key.offset: 87,
+            key.offset: 61,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -223,14 +205,14 @@ public func publicFunc()
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "publicMethod()",
-        key.offset: 135,
+        key.offset: 109,
         key.length: 26,
         key.typename: "Int",
-        key.nameoffset: 140,
+        key.nameoffset: 114,
         key.namelength: 14,
         key.attributes: [
           {
-            key.offset: 128,
+            key.offset: 102,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -240,13 +222,13 @@ public func publicFunc()
         key.kind: source.lang.swift.decl.function.method.instance,
         key.accessibility: source.lang.swift.accessibility.public,
         key.name: "init(public:)",
-        key.offset: 174,
+        key.offset: 148,
         key.length: 17,
-        key.nameoffset: 174,
+        key.nameoffset: 148,
         key.namelength: 17,
         key.attributes: [
           {
-            key.offset: 167,
+            key.offset: 141,
             key.length: 6,
             key.attribute: source.decl.attribute.public
           }
@@ -255,10 +237,10 @@ public func publicFunc()
           {
             key.kind: source.lang.swift.decl.var.parameter,
             key.name: "public",
-            key.offset: 179,
+            key.offset: 153,
             key.length: 11,
             key.typename: "Int",
-            key.nameoffset: 179,
+            key.nameoffset: 153,
             key.namelength: 6
           }
         ]
@@ -269,13 +251,13 @@ public func publicFunc()
     key.kind: source.lang.swift.decl.function.free,
     key.accessibility: source.lang.swift.accessibility.public,
     key.name: "publicFunc()",
-    key.offset: 202,
+    key.offset: 176,
     key.length: 17,
-    key.nameoffset: 207,
+    key.nameoffset: 181,
     key.namelength: 12,
     key.attributes: [
       {
-        key.offset: 195,
+        key.offset: 169,
         key.length: 6,
         key.attribute: source.decl.attribute.public
       }
diff --git a/test/SourceKit/Macros/clang-overload-cursor-info.swift b/test/SourceKit/Macros/clang-overload-cursor-info.swift
new file mode 100644
index 0000000000000..a15687f8bc6a9
--- /dev/null
+++ b/test/SourceKit/Macros/clang-overload-cursor-info.swift
@@ -0,0 +1,61 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+//--- Main.swift
+import FromClang // NOTE: line offset = -4
+
+// REQUIRES: swift_feature_SafeInteropWrappers
+// REQUIRES: swift_feature_LifetimeDependence
+
+// The macro-generated interface we're looking up source info for
+// (this is more so for documentation than checking correctness)
+//
+// INTERFACE:      @_alwaysEmitIntoClient @_disfavoredOverload public func hasBufferOverload(_ p: UnsafeMutableBufferPointer<Int32>)
+// INTERFACE:      @{{_?}}lifetime(p: copy p)
+// INTERFACE-NEXT: @_alwaysEmitIntoClient @_disfavoredOverload public func hasSpanOverload(_ p: inout MutableSpan<Int32>)
+// RUN: %target-swift-ide-test \
+// RUN:   -print-module -module-to-print=FromClang -source-filename=x \
+// RUN:   -plugin-path %swift-plugin-dir -I %t/Inputs \
+// RUN:   -enable-experimental-feature SafeInteropWrappers \
+// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN: | %FileCheck %t/Main.swift --check-prefix INTERFACE
+
+@inlinable
+public func callWithBufferPtr(_ p: UnsafeMutableBufferPointer<CInt>) {
+  hasBufferOverload(p)
+// RUN: %sourcekitd-test -req=cursor -pos=%(line-4):3 %t/Main.swift -- -I %t/Inputs %t/Main.swift \
+// RUN:   -enable-experimental-feature SafeInteropWrappers \
+// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN: | %FileCheck %t/Inputs/from-clang.h --check-prefix BUFFER-OVERLOAD
+}
+
+@available(visionOS 1.1, tvOS 12.2, watchOS 5.2, iOS 12.2, macOS 10.14.4, *)
+@lifetime(p: copy p)
+@inlinable
+public func callReturnLifetimeBound(_ p: inout MutableSpan<CInt>) {
+  hasSpanOverload(p)
+// RUN: %sourcekitd-test -req=cursor -pos=%(line-4):3 %t/Main.swift -- -I %t/Inputs %t/Main.swift \
+// RUN:   -enable-experimental-feature SafeInteropWrappers \
+// RUN:   -enable-experimental-feature LifetimeDependence \
+// RUN: | %FileCheck %t/Inputs/from-clang.h --check-prefix SPAN-OVERLOAD
+}
+
+//--- Inputs/module.modulemap
+module FromClang {
+    header "from-clang.h"
+    export *
+}
+
+//--- Inputs/from-clang.h
+#pragma once
+
+#define __counted_by(x) __attribute__((__counted_by__(x)))
+#define __noescape __attribute__((noescape))
+#define __lifetimebound __attribute__((lifetimebound))
+
+void hasBufferOverload(int len, int * __counted_by(len) p);
+// BUFFER-OVERLOAD:      source.lang.swift.ref.function.free
+// BUFFER-OVERLOAD-SAME: from-clang.h:[[@LINE-2]]
+
+void hasSpanOverload(int len, int * __counted_by(len) __noescape p);
+// SPAN-OVERLOAD:      source.lang.swift.ref.function.free
+// SPAN-OVERLOAD-SAME: from-clang.h:[[@LINE-2]]
diff --git a/test/SourceKit/Macros/expansion_decl_cursor_info.swift b/test/SourceKit/Macros/expansion_decl_cursor_info.swift
new file mode 100644
index 0000000000000..e7399f47e6fb9
--- /dev/null
+++ b/test/SourceKit/Macros/expansion_decl_cursor_info.swift
@@ -0,0 +1,46 @@
+// RUN: %empty-directory(%t)
+// REQUIRES: swift_swift_parser
+
+// RUN: split-file --leading-lines %s %t
+
+// RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %t/MacroDefinition.swift -g -no-toolchain-stdlib-rpath
+
+//--- MacroDefinition.swift
+
+import SwiftSyntax
+import SwiftSyntaxMacros
+
+public struct AddFuncMacro: DeclarationMacro, PeerMacro {
+  public static func expansion(
+    of macro: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) -> [DeclSyntax] {
+    ["func foo(_ x: String) {}"]
+  }
+  public static func expansion(
+    of node: AttributeSyntax,
+    providingPeersOf declaration: some DeclSyntaxProtocol,
+    in context: some MacroExpansionContext
+  ) throws -> [DeclSyntax] {
+    ["func foo(_ x: Int) {}"]
+  }
+}
+
+//--- main.swift
+
+@attached(peer, names: named(foo))
+macro AddFuncPeer(x: Int) = #externalMacro(module: "MacroDefinition", type: "AddFuncMacro")
+
+@freestanding(declaration, names: named(foo))
+macro AddFunc(x: Int) = #externalMacro(module: "MacroDefinition", type: "AddFuncMacro")
+
+@AddFuncPeer(x: 0)
+#AddFunc(x: 0)
+
+foo(0)
+// RUN: %sourcekitd-test -req=cursor %t/main.swift -pos=%(line-1):1 -- %t/main.swift -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser | %FileCheck --check-prefix PEER %s
+// PEER: source.lang.swift.ref.function.free ([[@LINE-5]]:1-[[@LINE-5]]:19)
+
+foo("")
+// RUN: %sourcekitd-test -req=cursor %t/main.swift -pos=%(line-1):1 -- %t/main.swift -load-plugin-library %t/%target-library-name(MacroDefinition) -module-name MacroUser | %FileCheck --check-prefix FREESTANDING %s
+// FREESTANDING: source.lang.swift.ref.function.free ([[@LINE-8]]:1-[[@LINE-8]]:15)
diff --git a/test/SourceKit/Misc/compiler_version.swift b/test/SourceKit/Misc/compiler_version.swift
index 6b448a028a73d..3fa5184c4322e 100644
--- a/test/SourceKit/Misc/compiler_version.swift
+++ b/test/SourceKit/Misc/compiler_version.swift
@@ -1,5 +1,5 @@
 // RUN: %sourcekitd-test -req=compiler-version | %FileCheck %s
 
 // CHECK: key.version_major: 6
-// CHECK: key.version_minor: 2
+// CHECK: key.version_minor: 3
 // CHECK: key.version_patch: 0
diff --git a/test/SourceKit/Misc/load-module-with-errors.swift b/test/SourceKit/Misc/load-module-with-errors.swift
index 8eb9c7d17b5d5..350926fa40eb7 100644
--- a/test/SourceKit/Misc/load-module-with-errors.swift
+++ b/test/SourceKit/Misc/load-module-with-errors.swift
@@ -17,11 +17,11 @@ func testInvalidStructMemberCompletion() {
   let foo: InvalidStruct
   foo.#^INVALID-MEMBER^#
   // INVALID-MEMBER-DAG: Decl[InstanceVar]/CurrNominal:      memberA[#Int#];
-  // INVALID-MEMBER-DAG: Decl[InstanceVar]/CurrNominal:      memberB[#<<error type>>#];
-  // INVALID-MEMBER-DAG: Decl[InstanceVar]/CurrNominal:      memberC[#<<error type>>#];
-  // INVALID-MEMBER-DAG: Decl[InstanceVar]/CurrNominal:      memberD[#<<error type>>#];
-  // INVALID-MEMBER-DAG: Decl[InstanceVar]/CurrNominal:      memberE[#<<error type>>#];
-  // INVALID-MEMBER-DAG: Decl[InstanceMethod]/Super:         add({#<<error type>>#})[#Void#];
+  // INVALID-MEMBER-DAG: Decl[InstanceVar]/CurrNominal:      memberB[#_#];
+  // INVALID-MEMBER-DAG: Decl[InstanceVar]/CurrNominal:      memberC[#_#];
+  // INVALID-MEMBER-DAG: Decl[InstanceVar]/CurrNominal:      memberD[#_#];
+  // INVALID-MEMBER-DAG: Decl[InstanceVar]/CurrNominal:      memberE[#_#];
+  // INVALID-MEMBER-DAG: Decl[InstanceMethod]/Super:         add({#_#})[#Void#];
   // INVALID-MEMBER-DAG: Decl[InstanceMethod]/Super:         get()[#InvalidStruct.Item#];
   // INVALID-MEMBER-DAG: Decl[InstanceMethod]/Super:         set({#item: InvalidStruct.Item#})[#Void#];
 }
@@ -45,21 +45,21 @@ func testInvalidTopLevelCompletion() {
   // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidGenericFuncBody({#param: T#})[#T#];
   // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidPartialFunc()[#Void#];
   // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidFuncBody()[#Void#];
-  // INVALID-TOP-DAG: Decl[GlobalVar]/OtherModule[errors]: invalidGlobalClosureBody[#<<error type>>#];
+  // INVALID-TOP-DAG: Decl[GlobalVar]/OtherModule[errors]: invalidGlobalClosureBody[#_#];
   // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidFuncSignature()[#Void#];
   // INVALID-TOP-DAG: Decl[GlobalVar]/OtherModule[errors]: invalidGlobalMissingInit[#String#];
   // INVALID-TOP-DAG: Decl[Struct]/OtherModule[errors]:   InvalidGenericStruct[#InvalidGenericStruct<T, U>#];
   // INVALID-TOP-DAG: Decl[Struct]/OtherModule[errors]:   InvalidStruct[#InvalidStruct#];
-  // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: typeUsesFunc({#pe: InvalidEnum#}, {#pa: <<error type>>#}, {#pp: any InvalidProtocol#}, {#ps: InvalidStruct#}, {#pg: <<error type>>#}, {#pc: InvalidClass#})[#Int#];
+  // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: typeUsesFunc({#pe: InvalidEnum#}, {#pa: _#}, {#pp: any InvalidProtocol#}, {#ps: InvalidStruct#}, {#pg: _#}, {#pc: InvalidClass#})[#Int#];
   // INVALID-TOP-DAG: Decl[GlobalVar]/OtherModule[errors]: invalidGlobalKeypath[#InvalidStruct.Type#];
   // INVALID-TOP-DAG: Decl[TypeAlias]/OtherModule[errors]: InvalidAlias[#InvalidAlias#];
-  // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidGenericFuncType({#param: T#})[#<<error type>>#];
-  // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidFuncType()[#<<error type>>#];
+  // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidGenericFuncType({#param: T#})[#_#];
+  // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidFuncType()[#_#];
   // INVALID-TOP-DAG: Decl[GlobalVar]/OtherModule[errors]: invalidGlobalClosureType[#() -> ()#];
   // INVALID-TOP-DAG: Decl[Class]/OtherModule[errors]:    InvalidClassSub1[#InvalidClassSub1#];
   // INVALID-TOP-DAG: Decl[Class]/OtherModule[errors]:    InvalidClassSub2[#InvalidClassSub2#];
   // INVALID-TOP-DAG: Decl[Protocol]/OtherModule[errors]/Flair[RareType]: InvalidProtocol[#InvalidProtocol#];
-  // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidFuncThrows()[' throws'][#<<error type>>#];
+  // INVALID-TOP-DAG: Decl[FreeFunction]/OtherModule[errors]: invalidFuncThrows()[' throws'][#_#];
 }
 
 // RUN: %empty-directory(%t)
diff --git a/test/SourceKit/Misc/rdar148130166.swift b/test/SourceKit/Misc/rdar148130166.swift
new file mode 100644
index 0000000000000..1ac4e076f54e0
--- /dev/null
+++ b/test/SourceKit/Misc/rdar148130166.swift
@@ -0,0 +1,5 @@
+// RUN: env DYLD_INSERT_LIBRARIES=/usr/lib/libgmalloc.dylib %sourcekitd-test -req=active-regions %s -- %s -module-name B -module-alias A=B
+// Make sure we don't crash.
+
+// guardmalloc is incompatible with ASAN
+// REQUIRES: no_asan
diff --git a/test/SourceKit/Misc/rdar98880399.swift b/test/SourceKit/Misc/rdar98880399.swift
new file mode 100644
index 0000000000000..541bfe797797a
--- /dev/null
+++ b/test/SourceKit/Misc/rdar98880399.swift
@@ -0,0 +1,4 @@
+// Make sure we don't create any temporary files.
+// RUN: %empty-directory(%t)
+// RUN: env TMP=%t TMPDIR=%t %sourcekitd-test -req=open %s -- %s -driver-force-response-files
+// RUN: not ls %t/* >/dev/null 2>&1
diff --git a/test/SourceKit/Refactoring/rdar155549979.swift b/test/SourceKit/Refactoring/rdar155549979.swift
new file mode 100644
index 0000000000000..c5102d4e9b2b3
--- /dev/null
+++ b/test/SourceKit/Refactoring/rdar155549979.swift
@@ -0,0 +1,105 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %sourcekitd-test -req=find-rename-ranges -rename-spec %t/spec.json %t/main.swift | %FileCheck %s
+
+// REQUIRES: swift_swift_parser
+
+//--- main.swift
+func foo() {}
+
+// Make sure we don't crash on the unrelated comment refs:
+// foo()
+// foo(0)
+// foo(a: 0)
+// foo {}
+// foo {} a: {}
+
+// Nor when written in code:
+foo()
+foo(0)
+foo(a: 0)
+foo {}
+foo {} a: {}
+
+// CHECK:      source.edit.kind.active:
+// CHECK-NEXT:   1:6-1:9 source.refactoring.range.kind.basename
+// CHECK-NEXT: source.edit.kind.comment:
+// CHECK-NEXT:   4:4-4:7 source.refactoring.range.kind.basename
+// CHECK-NEXT: source.edit.kind.unknown:
+// CHECK-NEXT:   5:4-5:7 source.refactoring.range.kind.basename
+// CHECK-NEXT: source.edit.kind.unknown:
+// CHECK-NEXT:   6:4-6:7 source.refactoring.range.kind.basename
+// CHECK-NEXT: source.edit.kind.unknown:
+// CHECK-NEXT:   7:4-7:7 source.refactoring.range.kind.basename
+// CHECK-NEXT: source.edit.kind.unknown:
+// CHECK-NEXT:   8:4-8:7 source.refactoring.range.kind.basename
+// CHECK-NEXT: source.edit.kind.active:
+// CHECK-NEXT:   11:1-11:4 source.refactoring.range.kind.basename
+// CHECK-NEXT: source.edit.kind.mismatch:
+// CHECK-NEXT: source.edit.kind.mismatch:
+// CHECK-NEXT: source.edit.kind.mismatch:
+// CHECK-NEXT: source.edit.kind.mismatch:
+
+//--- spec.json
+[
+  {
+    "key.name": "foo()",
+    "key.locations": [
+      {
+        "key.line": 1,
+        "key.column": 6,
+        "key.nametype": source.syntacticrename.definition
+      },
+      {
+        "key.line": 4,
+        "key.column": 4,
+        "key.nametype": source.syntacticrename.unknown
+      },
+      {
+        "key.line": 5,
+        "key.column": 4,
+        "key.nametype": source.syntacticrename.unknown
+      },
+      {
+        "key.line": 6,
+        "key.column": 4,
+        "key.nametype": source.syntacticrename.unknown
+      },
+      {
+        "key.line": 7,
+        "key.column": 4,
+        "key.nametype": source.syntacticrename.unknown
+      },
+      {
+        "key.line": 8,
+        "key.column": 4,
+        "key.nametype": source.syntacticrename.unknown
+      },
+      {
+        "key.line": 11,
+        "key.column": 1,
+        "key.nametype": source.syntacticrename.call
+      },
+      {
+        "key.line": 12,
+        "key.column": 1,
+        "key.nametype": source.syntacticrename.call
+      },
+      {
+        "key.line": 13,
+        "key.column": 1,
+        "key.nametype": source.syntacticrename.call
+      },
+      {
+        "key.line": 14,
+        "key.column": 1,
+        "key.nametype": source.syntacticrename.call
+      },
+      {
+        "key.line": 15,
+        "key.column": 1,
+        "key.nametype": source.syntacticrename.call
+      },
+    ]
+  }
+]
diff --git a/test/SourceKit/Sema/educational_note_diags.swift b/test/SourceKit/Sema/educational_note_diags.swift
index baec66c00c2c9..25802360345fb 100644
--- a/test/SourceKit/Sema/educational_note_diags.swift
+++ b/test/SourceKit/Sema/educational_note_diags.swift
@@ -1,17 +1,17 @@
-typealias Crap = () -> ()
-extension Crap {}
+typealias Foo = () -> ()
+extension Foo {}
 
 // RUN: %sourcekitd-test -req=sema %s -- %s | %FileCheck %s -check-prefix=NO_OVERRIDE
 
 // NO_OVERRIDE:      key.description: "non-nominal type
 // NO_OVERRIDE:      key.educational_note_paths: [
-// NO_OVERRIDE-NEXT:   share{{[/\\]+}}doc{{[/\\]+}}swift{{[/\\]+}}diagnostics{{[/\\]+}}nominal-types.md"
+// NO_OVERRIDE-NEXT:   "https://docs.swift.org/compiler/documentation/diagnostics/nominal-types"
 // NO_OVERRIDE-NEXT: ]
 
 // RUN: %sourcekitd-test -req=sema %s -- -Xfrontend -diagnostic-documentation-path -Xfrontend /educational/notes/path/prefix %s | %FileCheck %s -check-prefix=OVERRIDE
 
 // OVERRIDE:      key.description: "non-nominal type
 // OVERRIDE:      key.educational_note_paths: [
-// OVERRIDE-NEXT:   "{{[/\\]+}}educational{{[/\\]+}}notes{{[/\\]+}}path{{[/\\]+}}prefix{{[/\\]+}}nominal-types.md"
+// OVERRIDE-NEXT:   "{{[/\\]+}}educational{{[/\\]+}}notes{{[/\\]+}}path{{[/\\]+}}prefix{{[/\\]+}}nominal-types"
 // OVERRIDE-NEXT: ]
 
diff --git a/test/SourceKit/SemanticTokens/raw_identifiers.swift b/test/SourceKit/SemanticTokens/raw_identifiers.swift
new file mode 100644
index 0000000000000..72a66e5ce2a9f
--- /dev/null
+++ b/test/SourceKit/SemanticTokens/raw_identifiers.swift
@@ -0,0 +1,33 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %sourcekitd-test -req=semantic-tokens %t/main.swift -- %t/main.swift > %t/result.json
+// RUN: diff -u %t/tokens.json %t/result.json
+
+//--- main.swift
+func `foo`(x: Int) {}
+`foo`(x: 0)
+
+func `foo bar baz`() {}
+`foo bar baz`()
+
+//--- tokens.json
+{
+  key.semantic_tokens: [
+    {
+      key.kind: source.lang.swift.ref.struct,
+      key.offset: 14,
+      key.length: 3,
+      key.is_system: 1
+    },
+    {
+      key.kind: source.lang.swift.ref.function.free,
+      key.offset: 22,
+      key.length: 5
+    },
+    {
+      key.kind: source.lang.swift.ref.function.free,
+      key.offset: 59,
+      key.length: 13
+    }
+  ]
+}
diff --git a/test/SourceKit/SignatureHelp/signature_help.swift b/test/SourceKit/SignatureHelp/signature_help.swift
new file mode 100644
index 0000000000000..e6bc51c1fb0a7
--- /dev/null
+++ b/test/SourceKit/SignatureHelp/signature_help.swift
@@ -0,0 +1,64 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %sourcekitd-test -req=signaturehelp -pos=18:10 %t/input.swift -- %t/input.swift > %t/actual.result
+// RUN: diff -u %t/expected.result %t/actual.result
+
+//--- input.swift
+struct Calculator {
+  /// Adds two numbers together.
+  ///
+  /// - Parameters:
+  ///   - x: The first number to add.
+  ///   - y: The second number to add.
+  /// - Returns: The sum of x and y.
+  func add(_ x: Int, to y: Int) -> Int {
+    return x + y
+  }
+  
+  func add(first: Double, second: Float) -> Double {
+    return first + Double(second)
+  }
+}
+
+let calc = Calculator()
+calc.add()
+
+//--- expected.result
+{
+  key.signatures: [
+    {
+      key.name: "add(_ x: Int, to: Int) -> Int",
+      key.doc_comment: "Adds two numbers together.\n\n- Parameters:\n  - x: The first number to add.\n  - y: The second number to add.\n- Returns: The sum of x and y.",
+      key.parameters: [
+        {
+          key.name: "x",
+          key.nameoffset: 4,
+          key.namelength: 8
+        },
+        {
+          key.name: "y",
+          key.nameoffset: 14,
+          key.namelength: 7
+        }
+      ],
+      key.active_parameter: 0
+    },
+    {
+      key.name: "add(first: Double, second: Float) -> Double",
+      key.parameters: [
+        {
+          key.name: "first",
+          key.nameoffset: 4,
+          key.namelength: 13
+        },
+        {
+          key.name: "second",
+          key.nameoffset: 19,
+          key.namelength: 13
+        }
+      ],
+      key.active_parameter: 0
+    }
+  ],
+  key.active_signature: 0
+}
diff --git a/test/StringProcessing/Parse/forward-slash-regex.swift b/test/StringProcessing/Parse/forward-slash-regex.swift
index ede49b43b176b..791eb8b3f61b8 100644
--- a/test/StringProcessing/Parse/forward-slash-regex.swift
+++ b/test/StringProcessing/Parse/forward-slash-regex.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-bare-slash-regex -disable-availability-checking -typo-correction-limit 0
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-bare-slash-regex -disable-availability-checking -typo-correction-limit 0
 // REQUIRES: swift_swift_parser
 // REQUIRES: concurrency
 
@@ -407,7 +407,6 @@ _ = /\()/
 // expected-error@-1 {{'/' is not a prefix unary operator}}
 // expected-error@-2 {{'/' is not a postfix unary operator}}
 // expected-error@-3 {{invalid component of Swift key path}}
-// expected-error@-4 {{type of expression is ambiguous without a type annotation}}
   
 do {
   let _: Regex = (/whatever\)/
@@ -446,6 +445,7 @@ _ = ^/"/"
 _ = ^/"[/"
 // expected-error@-1 {{'^' is not a prefix unary operator}}
 // expected-error@-2 {{unterminated string literal}}
+// expected-error@-3 {{cannot parse regular expression: expected custom character class members}}
 
 _ = (^/)("/")
 
diff --git a/test/StringProcessing/Sema/regex_builder_already_imported.swift b/test/StringProcessing/Sema/regex_builder_already_imported.swift
index bd200d784d5b9..e7f9b7a08a9b7 100644
--- a/test/StringProcessing/Sema/regex_builder_already_imported.swift
+++ b/test/StringProcessing/Sema/regex_builder_already_imported.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-bare-slash-regex -disable-availability-checking
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-bare-slash-regex -disable-availability-checking
 
 import RegexBuilder
 
diff --git a/test/SymbolGraph/ClangImporter/HeaderNameCollision.swift b/test/SymbolGraph/ClangImporter/HeaderNameCollision.swift
new file mode 100644
index 0000000000000..56ba173b7a263
--- /dev/null
+++ b/test/SymbolGraph/ClangImporter/HeaderNameCollision.swift
@@ -0,0 +1,53 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-symbolgraph-extract -sdk %clang-importer-sdk -module-name HeaderCollision -F %t -output-dir %t -pretty-print -v
+// RUN: %FileCheck %s --input-file %t/HeaderCollision.symbols.json --check-prefix MODULE
+// RUN: %FileCheck %s --input-file %t/HeaderCollision@Dependency.symbols.json --check-prefix EXTENSION
+
+// REQUIRES: objc_interop
+
+// Ensure that extensions to a dependency's types, declared in a header with the same name as the
+// dependency's type's header, correctly get sorted into an extension header rather than the module
+// itself.
+
+// MODULE: "symbols": []
+// EXTENSION: "precise": "c:objc(cs)DependencyClass(im)addNumber:to:"
+
+//--- Dependency.framework/Modules/module.modulemap
+framework module Dependency {
+    umbrella header "Dependency.h"
+    export *
+    module * { export * }
+}
+
+//--- Dependency.framework/Headers/Dependency.h
+#import <Dependency/DependencyClass.h>
+
+//--- Dependency.framework/Headers/DependencyClass.h
+@import Foundation;
+
+@class DependencyClass;
+
+@interface DependencyClass : NSObject
+
+@end
+
+//--- HeaderCollision.framework/Modules/module.modulemap
+framework module HeaderCollision {
+    umbrella header "HeaderCollision.h"
+    export *
+    module * { export * }
+}
+
+//--- HeaderCollision.framework/Headers/HeaderCollision.h
+#import <HeaderCollision/DependencyClass.h>
+
+//--- HeaderCollision.framework/Headers/DependencyClass.h
+#import <Dependency/DependencyClass.h>
+
+@interface DependencyClass (HeaderCollisionClassAdditions)
+
+- (NSInteger)addNumber:(NSInteger)x to:(NSInteger)y;
+
+@end
diff --git a/test/SymbolGraph/ClangImporter/ObjCInitializer.swift b/test/SymbolGraph/ClangImporter/ObjCInitializer.swift
new file mode 100644
index 0000000000000..77dce000ee320
--- /dev/null
+++ b/test/SymbolGraph/ClangImporter/ObjCInitializer.swift
@@ -0,0 +1,28 @@
+// REQUIRES: objc_interop
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-symbolgraph-extract -sdk %clang-importer-sdk -module-name ObjCInitializer -Fsystem %t -output-dir %t -pretty-print -v
+// RUN: %FileCheck %s --input-file %t/ObjCInitializer.symbols.json
+// RUN: %FileCheck %s --input-file %t/ObjCInitializer.symbols.json --check-prefix SYNTH
+
+//--- ObjCInitializer.framework/Modules/module.modulemap
+framework module ObjCInitializer [system] {
+    header "ObjCInitializer.h"
+}
+
+//--- ObjCInitializer.framework/Headers/ObjCInitializer.h
+@import Foundation;
+
+@interface NSScrubberLayoutAttributes : NSObject <NSCopying>
+
+// This initializer gets imported twice - once as `init(forItemAt:)` and once as
+// `init(forItemAtIndex:)`. Make sure one of them gets a synthesized USR
+// CHECK:     "precise": "c:objc(cs)NSScrubberLayoutAttributes(cm)layoutAttributesForItemAtIndex:"
+// CHECK-NOT: "precise": "c:objc(cs)NSScrubberLayoutAttributes(cm)layoutAttributesForItemAtIndex:"
+// SYNTH:     "precise": "c:objc(cs)NSScrubberLayoutAttributes(cm)layoutAttributesForItemAtIndex:::SYNTHESIZED::c:objc(cs)NSScrubberLayoutAttributes",
+// SYNTH-NOT: "precise": "c:objc(cs)NSScrubberLayoutAttributes(cm)layoutAttributesForItemAtIndex:::SYNTHESIZED::c:objc(cs)NSScrubberLayoutAttributes",
++ (instancetype)layoutAttributesForItemAtIndex:(NSInteger)index;
+
+@end
diff --git a/test/SymbolGraph/ClangImporter/ProtocolInitializer.swift b/test/SymbolGraph/ClangImporter/ProtocolInitializer.swift
new file mode 100644
index 0000000000000..c52423be030c5
--- /dev/null
+++ b/test/SymbolGraph/ClangImporter/ProtocolInitializer.swift
@@ -0,0 +1,32 @@
+// REQUIRES: objc_interop
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-symbolgraph-extract -sdk %clang-importer-sdk -module-name ProtocolInitializer -I %t/ProtocolInitializer -output-dir %t -pretty-print -v
+// RUN: %FileCheck %s --input-file %t/ProtocolInitializer.symbols.json
+
+// the initializer's base USR should only appear as the source of one relationship
+// CHECK: "source": "c:objc(pl)MyProtocol(im)initWithSomeNumber:"
+// CHECK-NOT: "source": "c:objc(pl)MyProtocol(im)initWithSomeNumber:"
+
+//--- ProtocolInitializer/module.modulemap
+module ProtocolInitializer {
+    header "ProtocolInitializer.h"
+}
+
+//--- ProtocolInitializer/ProtocolInitializer.h
+@import Foundation;
+
+@protocol MyProtocol <NSObject>
+
+@optional
+- (nullable id)initWithSomeNumber:(NSInteger)number;
+
+@end
+
+@interface MyClass : NSObject
+@end
+
+@interface MyClass () <MyProtocol>
+@end
diff --git a/test/SymbolGraph/Relationships/MemberOf/Basic.swift b/test/SymbolGraph/Relationships/MemberOf/Basic.swift
index cdfa1b2f81c32..43708496f4f37 100644
--- a/test/SymbolGraph/Relationships/MemberOf/Basic.swift
+++ b/test/SymbolGraph/Relationships/MemberOf/Basic.swift
@@ -1,7 +1,9 @@
 // RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/Output)
 // RUN: %target-build-swift %s -module-name Basic -emit-module -emit-module-path %t/
-// RUN: %target-swift-symbolgraph-extract -module-name Basic -I %t -pretty-print -output-dir %t
-// RUN: %FileCheck %s --input-file %t/Basic.symbols.json 
+// RUN: %target-swift-symbolgraph-extract -module-name Basic -I %t -pretty-print -output-dir %t/Output
+// RUN: %FileCheck %s --input-file %t/Output/Basic.symbols.json
+
 public struct S {
   public var x: Int
 }
diff --git a/test/SymbolGraph/Symbols/DocComment/SkipInherited.swift b/test/SymbolGraph/Symbols/DocComment/SkipInherited.swift
new file mode 100644
index 0000000000000..4a7b39725dd10
--- /dev/null
+++ b/test/SymbolGraph/Symbols/DocComment/SkipInherited.swift
@@ -0,0 +1,19 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -module-name SkipInheritedDocs -emit-module-path %t/SkipInheritedDocs.swiftmodule
+// RUN: %target-swift-symbolgraph-extract -module-name SkipInheritedDocs -I %t -pretty-print -skip-inherited-docs -output-dir %t
+// RUN: %FileCheck %s --input-file %t/SkipInheritedDocs.symbols.json
+
+/// Parent docs.
+public protocol P1 {
+  /// Parent func docs.
+  func p2()
+}
+
+/// Child docs
+public class C1: P1 {
+  public func p2() {}
+}
+
+// CHECK: "Parent func docs."
+// CHECK-NOT: "Parent func docs."
+
diff --git a/test/SymbolGraph/Symbols/Macro.swift b/test/SymbolGraph/Symbols/Macro.swift
index af377b6376bac..54456f9944195 100644
--- a/test/SymbolGraph/Symbols/Macro.swift
+++ b/test/SymbolGraph/Symbols/Macro.swift
@@ -1,4 +1,4 @@
-// REQUIRES: swift_swift_parser, executable_test
+// REQUIRES: swift_swift_parser, executable_test, string_processing
 
 // RUN: %empty-directory(%t)
 
diff --git a/test/SymbolGraph/Symbols/Mixins/Availability/AvailabilityFilter.swift b/test/SymbolGraph/Symbols/Mixins/Availability/AvailabilityFilter.swift
new file mode 100644
index 0000000000000..846c537185aba
--- /dev/null
+++ b/test/SymbolGraph/Symbols/Mixins/Availability/AvailabilityFilter.swift
@@ -0,0 +1,63 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -module-name AvailabilityFilter -emit-module -emit-module-path %t/AvailabilityFilter.swiftmodule -emit-symbol-graph -emit-symbol-graph-dir %t/
+// RUN: %FileCheck %s --input-file %t/AvailabilityFilter.symbols.json --check-prefix DEFAULT
+
+// RUN: %target-swift-symbolgraph-extract -module-name AvailabilityFilter -I %t -pretty-print -output-dir %t
+// RUN: %FileCheck %s --input-file %t/AvailabilityFilter.symbols.json --check-prefix DEFAULT
+
+// Now checking the allowlist behavior...
+
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -module-name AvailabilityFilter -emit-module -emit-module-path %t/AvailabilityFilter.swiftmodule -emit-symbol-graph -emit-symbol-graph-dir %t/ -symbol-graph-allow-availability-platforms macOS,iOS
+// RUN: %FileCheck %s --input-file %t/AvailabilityFilter.symbols.json --check-prefix ALLOWLIST
+
+// RUN: %target-swift-symbolgraph-extract -module-name AvailabilityFilter -I %t -pretty-print -output-dir %t -allow-availability-platforms macOS,iOS
+// RUN: %FileCheck %s --input-file %t/AvailabilityFilter.symbols.json --check-prefix ALLOWLIST
+
+// Now checking the blocklist behavior...
+
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -module-name AvailabilityFilter -emit-module -emit-module-path %t/AvailabilityFilter.swiftmodule -emit-symbol-graph -emit-symbol-graph-dir %t/ -symbol-graph-block-availability-platforms macOS,iOS
+// RUN: %FileCheck %s --input-file %t/AvailabilityFilter.symbols.json --check-prefix BLOCKLIST
+
+// RUN: %target-swift-symbolgraph-extract -module-name AvailabilityFilter -I %t -pretty-print -output-dir %t -block-availability-platforms macOS,iOS
+// RUN: %FileCheck %s --input-file %t/AvailabilityFilter.symbols.json --check-prefix BLOCKLIST
+
+// Now test to ensure an empty allow list filters out all availability...
+
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -module-name AvailabilityFilter -emit-module -emit-module-path %t/AvailabilityFilter.swiftmodule -emit-symbol-graph -emit-symbol-graph-dir %t/ -symbol-graph-allow-availability-platforms ""
+// RUN: %FileCheck %s --input-file %t/AvailabilityFilter.symbols.json --check-prefix EMPTY
+
+// RUN: %target-swift-symbolgraph-extract -module-name AvailabilityFilter -I %t -pretty-print -output-dir %t -allow-availability-platforms ""
+// RUN: %FileCheck %s --input-file %t/AvailabilityFilter.symbols.json --check-prefix EMPTY
+
+// REQUIRES: OS=macosx
+
+@available(macOS 11.0, iOS 15.0, watchOS 15.0, *)
+public struct S {}
+
+/// Ensure that regardless of platforms being removed, that universal availability info,
+/// like unconditional deprecation, still lands in the symbol graph.
+@available(*, deprecated)
+public class C {}
+
+// DEFAULT-DAG: "domain":{{ ?}}"macOS"
+// DEFAULT-DAG: "domain":{{ ?}}"iOS"
+// DEFAULT-DAG: "domain":{{ ?}}"watchOS"
+// DEFAULT-DAG: "isUnconditionallyDeprecated":{{ ?}}true
+
+// ALLOWLIST-NOT: "domain":{{ ?}}"watchOS"
+// ALLOWLIST-DAG: "domain":{{ ?}}"macOS"
+// ALLOWLIST-DAG: "domain":{{ ?}}"iOS"
+// ALLOWLIST-DAG: "isUnconditionallyDeprecated":{{ ?}}true
+
+// BLOCKLIST-NOT: "domain":{{ ?}}"macOS"
+// BLOCKLIST-NOT: "domain":{{ ?}}"iOS"
+// BLOCKLIST-DAG: "domain":{{ ?}}"watchOS"
+// BLOCKLIST-DAG: "isUnconditionallyDeprecated":{{ ?}}true
+
+// EMPTY-NOT: "domain":{{ ?}}"macOS"
+// EMPTY-NOT: "domain":{{ ?}}"iOS"
+// EMPTY-NOT: "domain":{{ ?}}"watchOS"
+// EMPTY-DAG: "isUnconditionallyDeprecated":{{ ?}}true
diff --git a/test/SymbolGraph/Symbols/Mixins/Availability/Basic.swift b/test/SymbolGraph/Symbols/Mixins/Availability/Basic.swift
index 6e3e294b249b7..00a1d53757620 100644
--- a/test/SymbolGraph/Symbols/Mixins/Availability/Basic.swift
+++ b/test/SymbolGraph/Symbols/Mixins/Availability/Basic.swift
@@ -5,7 +5,7 @@
 
 // REQUIRES: OS=macosx
 
-@available(macOS, introduced: 10.9, deprecated: 11.0, obsoleted: 18.1, message: "Everyone makes mistakes", renamed: "S2")
+@available(macOS, introduced: 10.9, deprecated: 11.0, obsoleted: 15.1, message: "Everyone makes mistakes", renamed: "S2")
 public struct S {}
 
 // CHECK: "domain": "macOS"
@@ -19,7 +19,7 @@ public struct S {}
 // CHECK-NEXT: "minor": 0
 
 // CHECK: obsoleted
-// CHECK-NEXT: "major": 18
+// CHECK-NEXT: "major": 15
 // CHECK-NEXT: "minor": 1
 
 // CHECK: "message": "Everyone makes mistakes"
diff --git a/test/SymbolGraph/Symbols/Mixins/Availability/Inherited/ObsoletedReplaced.swift b/test/SymbolGraph/Symbols/Mixins/Availability/Inherited/ObsoletedReplaced.swift
index c9f7c86039748..1dd9f5b92b259 100644
--- a/test/SymbolGraph/Symbols/Mixins/Availability/Inherited/ObsoletedReplaced.swift
+++ b/test/SymbolGraph/Symbols/Mixins/Availability/Inherited/ObsoletedReplaced.swift
@@ -10,19 +10,19 @@
 
 // REQUIRES: OS=macosx
 
-@available(macOS, obsoleted: 18.14)
+@available(macOS, obsoleted: 98.14)
 public struct S {
   // LESSTHAN-LABEL: "precise": "s:17ObsoletedReplaced1SV8lessThanyyF",
   // LESSTHAN: "availability": [
   // LESSTHAN-NEXT:   {
   // LESSTHAN-NEXT:     "domain": "macOS",
   // LESSTHAN-NEXT:     "obsoleted": {
-  // LESSTHAN-NEXT:       "major": 18,
+  // LESSTHAN-NEXT:       "major": 98,
   // LESSTHAN-NEXT:       "minor": 10
   // LESSTHAN-NEXT:     }
   // LESSTHAN-NEXT:   }
   // LESSTHAN-NEXT: ]
-  @available(macOS, obsoleted: 18.10)
+  @available(macOS, obsoleted: 98.10)
   public func lessThan() {}
 
   // GREATERTHAN-LABEL: "precise": "s:17ObsoletedReplaced1SV11greaterThanyyF",
@@ -30,12 +30,12 @@ public struct S {
   // GREATERTHAN-NEXT:   {
   // GREATERTHAN-NEXT:     "domain": "macOS",
   // GREATERTHAN-NEXT:     "obsoleted": {
-  // GREATERTHAN-NEXT:       "major": 18,
+  // GREATERTHAN-NEXT:       "major": 98,
   // GREATERTHAN-NEXT:       "minor": 14
   // GREATERTHAN-NEXT:     }
   // GREATERTHAN-NEXT:   }
   // GREATERTHAN-NEXT: ]
-  @available(macOS, obsoleted: 18.15)
+  @available(macOS, obsoleted: 98.15)
   public func greaterThan() {}
 
   // EQUAL-LABEL: "precise": "s:17ObsoletedReplaced1SV5equalyyF",
@@ -43,16 +43,16 @@ public struct S {
   // EQUAL-NEXT:   {
   // EQUAL-NEXT:     "domain": "macOS",
   // EQUAL-NEXT:     "obsoleted": {
-  // EQUAL-NEXT:       "major": 18,
+  // EQUAL-NEXT:       "major": 98,
   // EQUAL-NEXT:       "minor": 14
   // EQUAL-NEXT:     }
   // EQUAL-NEXT:   }
   // EQUAL-NEXT: ]
-  @available(macOS, obsoleted: 18.14)
+  @available(macOS, obsoleted: 98.14)
   public func equal() {}
 }
 
-@available(macOS, obsoleted: 18.14)
+@available(macOS, obsoleted: 98.14)
 public struct Outer {
   public struct Inner {
     // TRANSITIVELESSTHAN-LABEL: "precise": "s:17ObsoletedReplaced5OuterV5InnerV8lessThanyyF"
@@ -60,12 +60,12 @@ public struct Outer {
     // TRANSITIVELESSTHAN-NEXT:   {
     // TRANSITIVELESSTHAN-NEXT:     "domain": "macOS",
     // TRANSITIVELESSTHAN-NEXT:     "obsoleted": {
-    // TRANSITIVELESSTHAN-NEXT:       "major": 18,
+    // TRANSITIVELESSTHAN-NEXT:       "major": 98,
     // TRANSITIVELESSTHAN-NEXT:       "minor": 10
     // TRANSITIVELESSTHAN-NEXT:     }
     // TRANSITIVELESSTHAN-NEXT:   }
     // TRANSITIVELESSTHAN-NEXT: ]
-    @available(macOS, obsoleted: 18.10)
+    @available(macOS, obsoleted: 98.10)
     public func lessThan() {}
 
     // TRANSITIVEGREATERTHAN-LABEL:"precise": "s:17ObsoletedReplaced5OuterV5InnerV11greaterThanyyF"
@@ -73,12 +73,12 @@ public struct Outer {
     // TRANSITIVEGREATERTHAN-NEXT:   {
     // TRANSITIVEGREATERTHAN-NEXT:     "domain": "macOS",
     // TRANSITIVEGREATERTHAN-NEXT:     "obsoleted": {
-    // TRANSITIVEGREATERTHAN-NEXT:       "major": 18,
+    // TRANSITIVEGREATERTHAN-NEXT:       "major": 98,
     // TRANSITIVEGREATERTHAN-NEXT:       "minor": 14
     // TRANSITIVEGREATERTHAN-NEXT:     }
     // TRANSITIVEGREATERTHAN-NEXT:   }
     // TRANSITIVEGREATERTHAN-NEXT: ]
-    @available(macOS, obsoleted: 18.15)
+    @available(macOS, obsoleted: 98.15)
     public func greaterThan() {}
 
     // TRANSITIVEEQUAL-LABEL:"precise": "s:17ObsoletedReplaced5OuterV5InnerV5equalyyF"
@@ -86,12 +86,12 @@ public struct Outer {
     // TRANSITIVEEQUAL-NEXT:   {
     // TRANSITIVEEQUAL-NEXT:     "domain": "macOS",
     // TRANSITIVEEQUAL-NEXT:     "obsoleted": {
-    // TRANSITIVEEQUAL-NEXT:       "major": 18,
+    // TRANSITIVEEQUAL-NEXT:       "major": 98,
     // TRANSITIVEEQUAL-NEXT:       "minor": 14
     // TRANSITIVEEQUAL-NEXT:     }
     // TRANSITIVEEQUAL-NEXT:   }
     // TRANSITIVEEQUAL-NEXT: ]
-    @available(macOS, obsoleted: 18.14)
+    @available(macOS, obsoleted: 98.14)
     public func equal() {}
   }
 }
diff --git a/test/SymbolGraph/Symbols/Mixins/DeclarationFragments/Full/Function.swift b/test/SymbolGraph/Symbols/Mixins/DeclarationFragments/Full/Function.swift
index e8201b21f2830..2c6fdfcf6baa3 100644
--- a/test/SymbolGraph/Symbols/Mixins/DeclarationFragments/Full/Function.swift
+++ b/test/SymbolGraph/Symbols/Mixins/DeclarationFragments/Full/Function.swift
@@ -1,111 +1,200 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift %s -module-name Function -emit-module -emit-module-path %t/
 // RUN: %target-swift-symbolgraph-extract -module-name Function -I %t -pretty-print -output-dir %t
-// RUN: %FileCheck %s --input-file %t/Function.symbols.json --match-full-lines --strict-whitespace
+// RUN: %FileCheck %s --input-file %t/Function.symbols.json --match-full-lines --strict-whitespace --check-prefix=FOO
+// RUN: %FileCheck %s --input-file %t/Function.symbols.json --match-full-lines --strict-whitespace --check-prefix=BAR
 
 public func foo<S>(f: @escaping () -> (), ext int: Int = 2, s: S) where S: Sequence {}
 
-// CHECK-LABEL:{{^      }}"declarationFragments": [
-// CHECK:        {
-// CHECK-NEXT:          "kind": "keyword",
-// CHECK-NEXT:          "spelling": "func"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": " "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "identifier",
-// CHECK-NEXT:          "spelling": "foo"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": "<"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "genericParameter",
-// CHECK-NEXT:          "spelling": "S"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": ">("
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "externalParam",
-// CHECK-NEXT:          "spelling": "f"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": ": "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "keyword",
-// CHECK-NEXT:          "spelling": "@escaping"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": " () -> (), "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "externalParam",
-// CHECK-NEXT:          "spelling": "ext"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": " "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "internalParam",
-// CHECK-NEXT:          "spelling": "int"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": ": "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "typeIdentifier",
-// CHECK-NEXT:          "spelling": "Int",
-// CHECK-NEXT:          "preciseIdentifier": "s:Si"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": " = 2, "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "externalParam",
-// CHECK-NEXT:          "spelling": "s"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": ": "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "typeIdentifier",
-// CHECK-NEXT:          "spelling": "S"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": ") "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "keyword",
-// CHECK-NEXT:          "spelling": "where"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": " "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "typeIdentifier",
-// CHECK-NEXT:          "spelling": "S"
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "text",
-// CHECK-NEXT:          "spelling": " : "
-// CHECK-NEXT:        },
-// CHECK-NEXT:        {
-// CHECK-NEXT:          "kind": "typeIdentifier",
-// CHECK-NEXT:          "spelling": "Sequence",
-// CHECK-NEXT:          "preciseIdentifier": "s:ST"
-// CHECK-NEXT:        }
-// CHECK-NEXT:      ],
+// FOO-LABEL:        "precise": "s:8Function3foo1f3ext1syyyc_SixtSTRzlF",
+// FOO:{{^      }}"declarationFragments": [
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "keyword",
+// FOO-NEXT:          "spelling": "func"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": " "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "identifier",
+// FOO-NEXT:          "spelling": "foo"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": "<"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "genericParameter",
+// FOO-NEXT:          "spelling": "S"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": ">("
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "externalParam",
+// FOO-NEXT:          "spelling": "f"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": ": "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "attribute",
+// FOO-NEXT:          "spelling": "@escaping "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": "() -> (), "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "externalParam",
+// FOO-NEXT:          "spelling": "ext"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": " "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "internalParam",
+// FOO-NEXT:          "spelling": "int"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": ": "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "typeIdentifier",
+// FOO-NEXT:          "spelling": "Int",
+// FOO-NEXT:          "preciseIdentifier": "s:Si"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": " = 2, "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "externalParam",
+// FOO-NEXT:          "spelling": "s"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": ": "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "typeIdentifier",
+// FOO-NEXT:          "spelling": "S"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": ") "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "keyword",
+// FOO-NEXT:          "spelling": "where"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": " "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "typeIdentifier",
+// FOO-NEXT:          "spelling": "S"
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "text",
+// FOO-NEXT:          "spelling": " : "
+// FOO-NEXT:        },
+// FOO-NEXT:        {
+// FOO-NEXT:          "kind": "typeIdentifier",
+// FOO-NEXT:          "spelling": "Sequence",
+// FOO-NEXT:          "preciseIdentifier": "s:ST"
+// FOO-NEXT:        }
+// FOO-NEXT:      ],
+
+public func bar<T>(_ apply: () -> T, onChange: @autoclosure () -> @Sendable () -> Void) {}
+
+// BAR-LABEL:        "precise": "s:8Function3bar_8onChangeyxyXE_yyYbcyXKtlF",
+// BAR:      "declarationFragments": [
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "keyword",
+// BAR-NEXT:          "spelling": "func"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": " "
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "identifier",
+// BAR-NEXT:          "spelling": "bar"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": "<"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "genericParameter",
+// BAR-NEXT:          "spelling": "T"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": ">("
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "externalParam",
+// BAR-NEXT:          "spelling": "_"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": " "
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "internalParam",
+// BAR-NEXT:          "spelling": "apply"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": ": () -> "
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "typeIdentifier",
+// BAR-NEXT:          "spelling": "T"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": ", "
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "externalParam",
+// BAR-NEXT:          "spelling": "onChange"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": ": "
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "attribute",
+// BAR-NEXT:          "spelling": "@autoclosure "
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": "() -> "
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "attribute",
+// BAR-NEXT:          "spelling": "@Sendable"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": " () -> "
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "typeIdentifier",
+// BAR-NEXT:          "spelling": "Void",
+// BAR-NEXT:          "preciseIdentifier": "s:s4Voida"
+// BAR-NEXT:        },
+// BAR-NEXT:        {
+// BAR-NEXT:          "kind": "text",
+// BAR-NEXT:          "spelling": ")"
+// BAR-NEXT:        }
+// BAR-NEXT:      ],
diff --git a/test/SymbolGraph/Symbols/Mixins/DeclarationFragments/Subheading/NominalTypes.swift b/test/SymbolGraph/Symbols/Mixins/DeclarationFragments/Subheading/NominalTypes.swift
index e3df5c6f7b70f..96b944ea53e2f 100644
--- a/test/SymbolGraph/Symbols/Mixins/DeclarationFragments/Subheading/NominalTypes.swift
+++ b/test/SymbolGraph/Symbols/Mixins/DeclarationFragments/Subheading/NominalTypes.swift
@@ -9,18 +9,18 @@
 
 // STRUCT-LABEL: "precise": "s:12NominalTypes6StructV"
 // STRUCT: subHeading
-// STRUCT-NEXT {
-// STRUCT-NEXT   "kind": "keyword",
-// STRUCT-NEXT   "spelling": "struct"
-// STRUCT-NEXT }
-// STRUCT-NEXT {
-// STRUCT-NEXT   "kind": "text",
-// STRUCT-NEXT   "spelling": " "
-// STRUCT-NEXT }
-// STRUCT-NEXT {
-// STRUCT-NEXT   "kind": "identifier",
-// STRUCT-NEXT   "spelling": "Struct"
-// STRUCT-NEXT }
+// STRUCT-NEXT: {
+// STRUCT-NEXT:   "kind": "keyword",
+// STRUCT-NEXT:   "spelling": "struct"
+// STRUCT-NEXT: }
+// STRUCT-NEXT: {
+// STRUCT-NEXT:   "kind": "text",
+// STRUCT-NEXT:   "spelling": " "
+// STRUCT-NEXT: }
+// STRUCT-NEXT: {
+// STRUCT-NEXT:   "kind": "identifier",
+// STRUCT-NEXT:   "spelling": "Struct"
+// STRUCT-NEXT: }
 public struct Struct<T> where T: Sequence {}
 
 // ENUM-LABEL: "precise": "s:12NominalTypes4EnumO"
@@ -59,18 +59,18 @@ public protocol Protocol where T: Sequence {
 
 // CLASS-LABEL: "precise": "s:12NominalTypes5ClassC"
 // CLASS: subHeading
-// CLASS-NEXT {
-// CLASS-NEXT   "kind": "keyword",
-// CLASS-NEXT   "spelling": "class"
-// CLASS-NEXT },
-// CLASS-NEXT {
-// CLASS-NEXT   "kind": "text",
-// CLASS-NEXT   "spelling": " "
-// CLASS-NEXT },
-// CLASS-NEXT {
-// CLASS-NEXT   "kind": "identifier",
-// CLASS-NEXT   "spelling": "Class"
-// CLASS-NEXT }
+// CLASS-NEXT: {
+// CLASS-NEXT:   "kind": "keyword",
+// CLASS-NEXT:   "spelling": "class"
+// CLASS-NEXT: },
+// CLASS-NEXT: {
+// CLASS-NEXT:   "kind": "text",
+// CLASS-NEXT:   "spelling": " "
+// CLASS-NEXT: },
+// CLASS-NEXT: {
+// CLASS-NEXT:   "kind": "identifier",
+// CLASS-NEXT:   "spelling": "Class"
+// CLASS-NEXT: }
 public class Class<T> where T: Sequence {}
 
 // TYPEALIAS-LABEL: "precise": "s:12NominalTypes9TypeAliasa"
diff --git a/test/SymbolGraph/Symbols/OriginallyDefinedInExtension.swift b/test/SymbolGraph/Symbols/OriginallyDefinedInExtension.swift
new file mode 100644
index 0000000000000..e77c8eef9172f
--- /dev/null
+++ b/test/SymbolGraph/Symbols/OriginallyDefinedInExtension.swift
@@ -0,0 +1,22 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/macos)
+// RUN: %empty-directory(%t/ios)
+
+// RUN: %target-swift-frontend -target %target-cpu-apple-macos %s -module-name OriginallyDefinedInExtension -emit-module -emit-module-path %t/macos/OriginallyDefinedInExtension.swiftmodule -emit-symbol-graph -emit-symbol-graph-dir %t/macos/
+// RUN: %FileCheck %s --input-file %t/macos/OriginallyDefinedInExtension.symbols.json
+// RUN: %target-swift-frontend -target %target-cpu-apple-ios-simulator %s -module-name OriginallyDefinedInExtension -emit-module -emit-module-path %t/ios/OriginallyDefinedInExtension.swiftmodule -emit-symbol-graph -emit-symbol-graph-dir %t/ios/
+// RUN: %FileCheck %s --input-file %t/ios/OriginallyDefinedInExtension.symbols.json
+
+// CHECK:   "precise":"s:28OriginallyDefinedInExtension12SimpleStructV05InnerF0V"
+
+// REQUIRES: SWIFT_SDK=osx
+// REQUIRES: SWIFT_SDK=ios_simulator
+
+@available(macOS 10.8, *)
+@_originallyDefinedIn(module: "another", macOS 11.0)
+public struct SimpleStruct {}
+
+@available(macOS 12.0, iOS 13.0, *)
+public extension SimpleStruct {
+    struct InnerStruct {}
+}
diff --git a/test/SymbolGraph/Symbols/SkipsSynthesizedMembers.swift b/test/SymbolGraph/Symbols/SkipsSynthesizedMembers.swift
new file mode 100644
index 0000000000000..19e7933c8e5a0
--- /dev/null
+++ b/test/SymbolGraph/Symbols/SkipsSynthesizedMembers.swift
@@ -0,0 +1,10 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -module-name SkipsSynthesizedMembers -emit-module -emit-module-path %t/
+// RUN: %target-swift-symbolgraph-extract -module-name SkipsSynthesizedMembers -I %t -pretty-print -skip-synthesized-members -output-dir %t
+// RUN: %FileCheck %s --input-file %t/SkipsSynthesizedMembers.symbols.json
+
+// CHECK-NOT: ::SYNTHESIZED
+
+public struct ShouldAppear: Hashable {
+    public let foo: Int
+}
diff --git a/test/SymbolGraph/infer-target.swift b/test/SymbolGraph/infer-target.swift
new file mode 100644
index 0000000000000..eb28e6372fd23
--- /dev/null
+++ b/test/SymbolGraph/infer-target.swift
@@ -0,0 +1,19 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/Output)
+// RUN: %target-build-swift %s -module-name Basic -emit-module -emit-module-path %t/
+
+// Verify that -target can be inferred
+// RUN: %empty-directory(%t/Output)
+// RUN: %swift-symbolgraph-extract -module-name Basic -I %t -pretty-print -output-dir %t/Output
+// RUN: %FileCheck %s --input-file %t/Output/Basic.symbols.json
+
+// This test can only work for test configurations that aren't cross-compiling.
+// REQUIRES: target-same-as-host
+
+public struct S {
+  public var x: Int
+}
+
+// CHECK: "kind": "memberOf"
+// CHECK-NEXT: "source": "s:5Basic1SV1xSivp"
+// CHECK-NEXT: "target": "s:5Basic1SV"
diff --git a/test/SynthesizeInterfaceTool/synthesize-interface.swift b/test/SynthesizeInterfaceTool/synthesize-interface.swift
index 426094d5429a2..7090ca7c893ee 100644
--- a/test/SynthesizeInterfaceTool/synthesize-interface.swift
+++ b/test/SynthesizeInterfaceTool/synthesize-interface.swift
@@ -1,4 +1,5 @@
 // RUN: %target-swift-synthesize-interface -module-name m1 -I %S/Inputs -o - | %FileCheck %s
+// RUN: %swift-synthesize-interface -module-name m1 -I %S/Inputs -o - | %FileCheck %s
 
 // CHECK:     public struct MyStruct {
 // CHECK-DAG:     public init()
diff --git a/test/TBD/Inputs/linker-directive.swift b/test/TBD/Inputs/linker-directive.swift
index d031b9ad110dc..ec8e804f6fadd 100644
--- a/test/TBD/Inputs/linker-directive.swift
+++ b/test/TBD/Inputs/linker-directive.swift
@@ -8,4 +8,20 @@ public struct Vehicle {
   public func move() {}
   @available(macOS 10.15, iOS 13, *)
   public func originallyDefinedInCurrentModule() {}
-}
\ No newline at end of file
+}
+
+@available(macOS 10.8, iOS 10.2, *)
+@_originallyDefinedIn(module: "ToasterKit", macOS 15, iOS 18)
+public func movedPriorTo26() {}
+
+@available(macOS 10.8, iOS 10.2, *)
+@_originallyDefinedIn(module: "ToasterKit", macOS 16, iOS 19)
+public func movedInVersionsMappingTo26() {}
+
+@available(macOS 10.8, iOS 10.2, *)
+@_originallyDefinedIn(module: "ToasterKit", macOS 17, iOS 20)
+public func movedInVersionsMappingTo27() {}
+
+@available(macOS 10.8, iOS 10.2, *)
+@_originallyDefinedIn(module: "ToasterKit", macOS 26, iOS 26)
+public func movedInVersion26() {}
diff --git a/test/TBD/coroutine_accessors.swift b/test/TBD/coroutine_accessors.swift
index cc2270cc0c3ce..2f557b2adb888 100644
--- a/test/TBD/coroutine_accessors.swift
+++ b/test/TBD/coroutine_accessors.swift
@@ -1,5 +1,6 @@
 // RUN: %target-build-swift-dylib(%t/%target-library-name(thing)) \
 // RUN:     %s                                                    \
+// RUN:     -Xfrontend -enable-callee-allocated-coro-abi          \
 // RUN:     -emit-tbd                                             \
 // RUN:     -Xfrontend -validate-tbd-against-ir=all               \
 // RUN:     -enable-library-evolution                             \
diff --git a/test/TBD/distributed_library_evolution.swift b/test/TBD/distributed_library_evolution.swift
index 58c931a571446..6ef9631d128d7 100644
--- a/test/TBD/distributed_library_evolution.swift
+++ b/test/TBD/distributed_library_evolution.swift
@@ -9,6 +9,7 @@
 // RUN:     -enable-library-evolution                                          \
 // RUN:     -disable-availability-checking                                     \
 // RUN:     -emit-ir -o %t/test.ll -emit-tbd                                   \
+// RUN:     -validate-tbd-against-ir=all                                       \
 // RUN:     -emit-tbd-path %t/library.tbd -I %t -tbd-install_name protocol
 
 // RUN: %target-swift-frontend %t/library.swift                                \
@@ -18,20 +19,23 @@
 // RUN:     -package-name Package                                              \
 // RUN:     -module-name Library                                               \
 // RUN:     -emit-module-path %t/Library.swiftmodule                           \
+// RUN:     -validate-tbd-against-ir=all                                       \
 // RUN:     -emit-module-interface-path %t/Library.swiftinterface
 
-// RUN: %target-swift-frontend %t/actor.swift -enable-library-evolution \
+// RUN: %target-swift-frontend %t/actor.swift -enable-library-evolution     \
+// RUN:     -enable-library-evolution                                       \
 // RUN:     -disable-availability-checking -emit-ir -o %t/test.ll -emit-tbd \
 // RUN:     -emit-tbd-path %t/actor.tbd -I %t -tbd-install_name actor
 
-// RUN: %target-swift-frontend %t/actor.swift  \
-// RUN:     -I %t                   \
-// RUN:     -disable-availability-checking \
+// RUN: %target-swift-frontend %t/actor.swift                              \
+// RUN:     -I %t                                                          \
+// RUN:     -disable-availability-checking                                 \
 // RUN:     -emit-module                                                   \
 // RUN:     -package-name Package                                          \
 // RUN:     -enable-library-evolution                                      \
 // RUN:     -module-name Client                                            \
-// RUN:     -emit-module-path %t/Client.swiftmodule                       \
+// RUN:     -emit-module-path %t/Client.swiftmodule                        \
+// RUN:     -validate-tbd-against-ir=all                                   \
 // RUN:     -emit-module-interface-path %t/Client.swiftinterface
 
 
diff --git a/test/TBD/linker-directives-ld-previous-ios.swift b/test/TBD/linker-directives-ld-previous-ios.swift
index ee3858eef2bdd..abea6c976d0a5 100644
--- a/test/TBD/linker-directives-ld-previous-ios.swift
+++ b/test/TBD/linker-directives-ld-previous-ios.swift
@@ -12,9 +12,17 @@
 // CHECK-objc-simulator-false: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$2$10.2$13.0$_$s10ToasterKit7VehicleVMa$
 // CHECK-objc-simulator-false: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$2$10.2$13.0$_$s10ToasterKit7VehicleVMn$
 // CHECK-objc-simulator-false: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$2$10.2$13.0$_$s10ToasterKit7VehicleVN$
+// CHECK-objc-simulator-false: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$2$10.2$18.0$_$s10ToasterKit14movedPriorTo26yyF
+// CHECK-objc-simulator-false: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$2$10.2$26.0$_$s10ToasterKit16movedInVersion26yyF$
+// CHECK-objc-simulator-false: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$2$10.2$26.0$_$s10ToasterKit26movedInVersionsMappingTo26yyF$
+// CHECK-objc-simulator-false: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$2$10.2$27.0$_$s10ToasterKit26movedInVersionsMappingTo27yyF$
 
 // CHECK-objc-simulator-true: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$7$10.2$13.0$_$s10ToasterKit5toastyyF$
 // CHECK-objc-simulator-true: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$7$10.2$13.0$_$s10ToasterKit7VehicleV4moveyyF$
 // CHECK-objc-simulator-true: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$7$10.2$13.0$_$s10ToasterKit7VehicleVMa$
 // CHECK-objc-simulator-true: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$7$10.2$13.0$_$s10ToasterKit7VehicleVMn$
 // CHECK-objc-simulator-true: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$7$10.2$13.0$_$s10ToasterKit7VehicleVN$
+// CHECK-objc-simulator-true: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$7$10.2$18.0$_$s10ToasterKit14movedPriorTo26yyF
+// CHECK-objc-simulator-true: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$7$10.2$26.0$_$s10ToasterKit16movedInVersion26yyF$
+// CHECK-objc-simulator-true: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$7$10.2$26.0$_$s10ToasterKit26movedInVersionsMappingTo26yyF$
+// CHECK-objc-simulator-true: D $ld$previous$/System/Previous/iOS/ToasterKit.dylib$$7$10.2$27.0$_$s10ToasterKit26movedInVersionsMappingTo27yyF$
diff --git a/test/TBD/linker-directives-ld-previous-macos.swift b/test/TBD/linker-directives-ld-previous-macos.swift
index 3e75b2a7daca9..559155a3b4dc8 100644
--- a/test/TBD/linker-directives-ld-previous-macos.swift
+++ b/test/TBD/linker-directives-ld-previous-macos.swift
@@ -18,11 +18,19 @@
 // CHECK-MACCATALYST: D $ld$previous$/System/Previous/macCatalyst/ToasterKit.dylib$$6$10.2$13.0$_$s10ToasterKit7VehicleVMa$
 // CHECK-MACCATALYST: D $ld$previous$/System/Previous/macCatalyst/ToasterKit.dylib$$6$10.2$13.0$_$s10ToasterKit7VehicleVMn$
 // CHECK-MACCATALYST: D $ld$previous$/System/Previous/macCatalyst/ToasterKit.dylib$$6$10.2$13.0$_$s10ToasterKit7VehicleVN$
+// CHECK-MACCATALYST: D $ld$previous$/System/Previous/macCatalyst/ToasterKit.dylib$$6$10.2$18.0$_$s10ToasterKit14movedPriorTo26yyF
+// CHECK-MACCATALYST: D $ld$previous$/System/Previous/macCatalyst/ToasterKit.dylib$$6$10.2$26.0$_$s10ToasterKit16movedInVersion26yyF$
+// CHECK-MACCATALYST: D $ld$previous$/System/Previous/macCatalyst/ToasterKit.dylib$$6$10.2$26.0$_$s10ToasterKit26movedInVersionsMappingTo26yyF$
+// CHECK-MACCATALYST: D $ld$previous$/System/Previous/macCatalyst/ToasterKit.dylib$$6$10.2$27.0$_$s10ToasterKit26movedInVersionsMappingTo27yyF$
 
 // CHECK-MAC: D $ld$previous$/System/Previous/macOS/ToasterKit.dylib$$1$10.8$10.15$_$s10ToasterKit5toastyyF$
 // CHECK-MAC: D $ld$previous$/System/Previous/macOS/ToasterKit.dylib$$1$10.8$10.15$_$s10ToasterKit7VehicleV4moveyyF$
 // CHECK-MAC: D $ld$previous$/System/Previous/macOS/ToasterKit.dylib$$1$10.8$10.15$_$s10ToasterKit7VehicleVMa$
 // CHECK-MAC: D $ld$previous$/System/Previous/macOS/ToasterKit.dylib$$1$10.8$10.15$_$s10ToasterKit7VehicleVMn$
 // CHECK-MAC: D $ld$previous$/System/Previous/macOS/ToasterKit.dylib$$1$10.8$10.15$_$s10ToasterKit7VehicleVN$
+// CHECK-MAC: D $ld$previous$/System/Previous/macOS/ToasterKit.dylib$$1$10.8$15.0$_$s10ToasterKit14movedPriorTo26yyF$
+// CHECK-MAC: D $ld$previous$/System/Previous/macOS/ToasterKit.dylib$$1$10.8$26.0$_$s10ToasterKit16movedInVersion26yyF$
+// CHECK-MAC: D $ld$previous$/System/Previous/macOS/ToasterKit.dylib$$1$10.8$26.0$_$s10ToasterKit26movedInVersionsMappingTo26yyF$
+// CHECK-MAC: D $ld$previous$/System/Previous/macOS/ToasterKit.dylib$$1$10.8$27.0$_$s10ToasterKit26movedInVersionsMappingTo27yyF$
 
 // CHECK-NOT: $_$s10ToasterKit7VehicleV32originallyDefinedInCurrentModuleyyF
diff --git a/test/TBD/linker-directives.swift b/test/TBD/linker-directives.swift
index 841c9e15747c9..8ec1f10c23896 100644
--- a/test/TBD/linker-directives.swift
+++ b/test/TBD/linker-directives.swift
@@ -4,10 +4,12 @@
 // RUN: %empty-directory(%t)
 
 // RUN: %target-swift-frontend -typecheck %s -tbd-install_name directive_use -tbd-is-installapi -emit-tbd -emit-tbd-path %t/linker_directives.tbd
+// RUN: %llvm-nm %t/linker_directives.tbd | %FileCheck %s --check-prefix CHECK-HAS
+// RUN: %llvm-nm %t/linker_directives.tbd | %FileCheck %s --check-prefix CHECK-HAS-NOT
 
-// RUN: %llvm-nm %t/linker_directives.tbd | %FileCheck %s --check-prefix CHECK-HAS --check-prefix CHECK-HAS-NOT 
 // RUN: %target-swift-frontend -typecheck %s -tbd-install_name directive_use -emit-tbd -emit-tbd-path %t/linker_directives.tbd
-// RUN: %llvm-nm %t/linker_directives.tbd | %FileCheck %s --check-prefix CHECK-HAS --check-prefix CHECK-HAS-NOT 
+// RUN: %llvm-nm %t/linker_directives.tbd | %FileCheck %s --check-prefix CHECK-HAS
+// RUN: %llvm-nm %t/linker_directives.tbd | %FileCheck %s --check-prefix CHECK-HAS-NOT
 
 @available(OSX 10.8, *)
 @_originallyDefinedIn(module: "ToasterKit", macOS 10.15)
@@ -18,3 +20,25 @@ public func toast() {}
 
 // CHECK-HAS-NOT-NOT: $ld$hide$os10.15$_$s10ToasterKit5toastyyF
 // CHECK-HAS-NOT-NOT: $ld$hide$os10.7$_$s10ToasterKit5toastyyF
+
+@available(macOS 15, *)
+@_originallyDefinedIn(module: "ToasterKit", macOS 16)
+public func toastMovedInVersionMappingTo26() {}
+
+// CHECK-HAS: D $ld$hide$os15.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os15.1$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os15.10$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// FIXME: Symbols shouldn't be generated for non-existent intermediate OS versions.
+// CHECK-HAS: D $ld$hide$os16.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os17.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os18.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os19.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os20.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os21.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os22.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os23.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os24.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS: D $ld$hide$os25.0$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+
+// CHECK-HAS-NOT-NOT: $ld$hide$os14.{{.*}}$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
+// CHECK-HAS-NOT-NOT: $ld$hide$os26.{{.*}}$_$s10ToasterKit30toastMovedInVersionMappingTo26yyF
diff --git a/test/TBD/multi-file.swift b/test/TBD/multi-file.swift
index c0af407aaf754..a1671adf7e1ce 100644
--- a/test/TBD/multi-file.swift
+++ b/test/TBD/multi-file.swift
@@ -7,7 +7,7 @@
 
 // RUN: %target-build-swift -swift-version 4 -module-name multifile -Xfrontend -tbd-install_name -Xfrontend multifile -emit-tbd-path %t/TBD-wmo.tbd -emit-module-path %t/multifile.swiftmodule %s %S/Inputs/multi-file2.swift -wmo
 // RUN: %target-build-swift -swift-version 4 -module-name multifile -Xfrontend -tbd-install_name -Xfrontend multifile -emit-tbd-path %t/TBD-incremental.tbd -emit-module-path %t/multifile.swiftmodule %s %S/Inputs/multi-file2.swift
-// RUN: diff %t/TBD-wmo.tbd %t/TBD-incremental.tbd
+// RUN: %llvm-readtapi --compare %t/TBD-wmo.tbd %t/TBD-incremental.tbd
 
 // -O, non-resilient
 
@@ -16,7 +16,7 @@
 
 // RUN: %target-build-swift -swift-version 4 -module-name multifile -Xfrontend -tbd-install_name -Xfrontend multifile -emit-tbd-path %t/TBD-wmo.tbd -emit-module-path %t/multifile.swiftmodule %s %S/Inputs/multi-file2.swift -wmo -O
 // RUN: %target-build-swift -swift-version 4 -module-name multifile -Xfrontend -tbd-install_name -Xfrontend multifile -emit-tbd-path %t/TBD-incremental.tbd -emit-module-path %t/multifile.swiftmodule %s %S/Inputs/multi-file2.swift -O
-// RUN: diff %t/TBD-wmo.tbd %t/TBD-incremental.tbd
+// RUN: %llvm-readtapi --compare %t/TBD-wmo.tbd %t/TBD-incremental.tbd
 
 // -Onone, resilient
 
@@ -25,7 +25,7 @@
 
 // RUN: %target-build-swift -swift-version 4 -module-name multifile -Xfrontend -tbd-install_name -Xfrontend multifile -emit-tbd-path %t/TBD-wmo.tbd -emit-module-path %t/multifile.swiftmodule %s %S/Inputs/multi-file2.swift -wmo -enable-library-evolution
 // RUN: %target-build-swift -swift-version 4 -module-name multifile -Xfrontend -tbd-install_name -Xfrontend multifile -emit-tbd-path %t/TBD-incremental.tbd -emit-module-path %t/multifile.swiftmodule %s %S/Inputs/multi-file2.swift -enable-library-evolution
-// RUN: diff %t/TBD-wmo.tbd %t/TBD-incremental.tbd
+// RUN: %llvm-readtapi --compare %t/TBD-wmo.tbd %t/TBD-incremental.tbd
 
 // -O, resilient
 
@@ -34,7 +34,7 @@
 
 // RUN: %target-build-swift -swift-version 4 -module-name multifile -Xfrontend -tbd-install_name -Xfrontend multifile -emit-tbd-path %t/TBD-wmo.tbd -emit-module-path %t/multifile.swiftmodule %s %S/Inputs/multi-file2.swift -wmo -O -enable-library-evolution
 // RUN: %target-build-swift -swift-version 4 -module-name multifile -Xfrontend -tbd-install_name -Xfrontend multifile -emit-tbd-path %t/TBD-incremental.tbd -emit-module-path %t/multifile.swiftmodule %s %S/Inputs/multi-file2.swift -O -enable-library-evolution
-// RUN: diff %t/TBD-wmo.tbd %t/TBD-incremental.tbd
+// RUN: %llvm-readtapi --compare %t/TBD-wmo.tbd %t/TBD-incremental.tbd
 
 // REQUIRES: objc_interop
 
diff --git a/test/TBD/objc-entry-point.swift b/test/TBD/objc-entry-point.swift
index 4ad97124a08a3..1e9f305c262ed 100644
--- a/test/TBD/objc-entry-point.swift
+++ b/test/TBD/objc-entry-point.swift
@@ -14,6 +14,6 @@ import AppKit
 let globalConstantWithLazyInitializer: String = "hello, world"
 
 @NSApplicationMain // expected-deprecated-warning {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-1 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-1 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate: NSObject, NSApplicationDelegate {
 }
diff --git a/test/TypeCoercion/integer_literals.swift b/test/TypeCoercion/integer_literals.swift
index 6ec8c4c55bfa9..86c44578faf65 100644
--- a/test/TypeCoercion/integer_literals.swift
+++ b/test/TypeCoercion/integer_literals.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 typealias IntegerLiteralType = Int32
 
diff --git a/test/Unsafe/codable_synthesis.swift b/test/Unsafe/codable_synthesis.swift
new file mode 100644
index 0000000000000..282db90cd2c09
--- /dev/null
+++ b/test/Unsafe/codable_synthesis.swift
@@ -0,0 +1,26 @@
+// RUN: %target-typecheck-verify-swift -strict-memory-safety
+
+@unsafe public struct UnsafeStruct: Codable {
+  public var string: String
+}
+
+
+@unsafe public enum UnsafeEnum: Codable {
+case something(Int)
+}
+
+@safe public struct SafeStruct: Codable {
+  public var us: UnsafeStruct
+}
+
+@safe public enum SafeEnum: Codable {
+case something(UnsafeEnum)
+}
+
+@unsafe public class C1: Codable {
+  public var string: String = ""
+}
+
+@unsafe public class C2: C1 {
+  public var otherString: String = ""
+}
diff --git a/test/Unsafe/hashable_synthesis.swift b/test/Unsafe/hashable_synthesis.swift
new file mode 100644
index 0000000000000..188f433462aad
--- /dev/null
+++ b/test/Unsafe/hashable_synthesis.swift
@@ -0,0 +1,18 @@
+// RUN: %target-typecheck-verify-swift -strict-memory-safety
+
+@unsafe public struct UnsafeStruct: Hashable {
+  public var string: String
+}
+
+
+@unsafe public enum UnsafeEnum: Hashable {
+case something(Int)
+}
+
+@safe public struct SafeStruct: Hashable {
+  public var us: UnsafeStruct
+}
+
+@safe public enum SafeEnum: Hashable {
+case something(UnsafeEnum)
+}
diff --git a/test/Unsafe/interface_printing.swift b/test/Unsafe/interface_printing.swift
deleted file mode 100644
index 0fd0e8c4de578..0000000000000
--- a/test/Unsafe/interface_printing.swift
+++ /dev/null
@@ -1,10 +0,0 @@
-// RUN: %empty-directory(%t)
-
-// RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -module-name unsafe -emit-module -o %t/unsafe.swiftmodule -emit-module-interface-path - %s | %FileCheck %s
-
-// CHECK: #if compiler(>=5.3) && $MemorySafetyAttributes
-// CHECK: @unsafe public func testFunction()
-// CHECK: #else
-// CHECK: public func testFunction()
-// CHECK: #endif
-@unsafe public func testFunction() { }
diff --git a/test/Unsafe/migrate.swift b/test/Unsafe/migrate.swift
new file mode 100644
index 0000000000000..5e422999e6b92
--- /dev/null
+++ b/test/Unsafe/migrate.swift
@@ -0,0 +1,21 @@
+// RUN: %target-swift-frontend -typecheck -verify -swift-version 6 -strict-memory-safety:migrate %s
+
+// REQUIRES: concurrency
+
+@preconcurrency import _Concurrency
+
+@unsafe func f() { }
+
+func g() {
+  f() // expected-warning{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{3-3=unsafe }}
+  // expected-note@-1{{reference to unsafe global function 'f()'}}
+}
+
+protocol P {
+  func f()
+}
+
+struct Conforming: P {
+  // expected-warning@-1{{conformance of 'Conforming' to protocol 'P' involves unsafe code; use '@unsafe' to indicate that the conformance is not memory-safe}}{{20-20=@unsafe }}
+  @unsafe func f() { } // expected-note{{unsafe instance method 'f()' cannot satisfy safe requirement}}
+}
diff --git a/test/Unsafe/module-interface.swift b/test/Unsafe/module-interface.swift
index a3443391a529d..f96909fccba61 100644
--- a/test/Unsafe/module-interface.swift
+++ b/test/Unsafe/module-interface.swift
@@ -2,11 +2,7 @@
 // RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -module-name UserModule
 // RUN: %FileCheck %s < %t.swiftinterface
 
-// CHECK: #if compiler(>=5.3) && $MemorySafetyAttributes
 // CHECK: @unsafe public func getIntUnsafely() -> Swift.Int
-// CHECK: #else
-// CHECK: public func getIntUnsafely() -> Swift.Int
-// CHECK: #endif
 @unsafe public func getIntUnsafely() -> Int { 0 }
 
 public struct UnsafeIterator: @unsafe IteratorProtocol {
@@ -33,13 +29,8 @@ public protocol P {
   func f()
 }
 
-// CHECK:  #if compiler(>=5.3) && $MemorySafetyAttributes
 // CHECK: public struct X : @unsafe UserModule.P
 public struct X: @unsafe P {
 // CHECK:  @unsafe public func f()
-// CHECK:  #else
-// CHECK: public struct X : UserModule.P
-// CHECK:  public func f()
-// CHECK:  #endif
   @unsafe public func f() { }
 }
diff --git a/test/Unsafe/preconcurrency_silence.swift b/test/Unsafe/preconcurrency_silence.swift
new file mode 100644
index 0000000000000..26c48a2fc98f9
--- /dev/null
+++ b/test/Unsafe/preconcurrency_silence.swift
@@ -0,0 +1,9 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module-path %t/unsafe_swift_decls.swiftmodule %S/Inputs/unsafe_swift_decls.swift
+
+// RUN: %target-typecheck-verify-swift -strict-memory-safety -enable-experimental-feature StrictConcurrency -I %t
+
+// REQUIRES: concurrency
+// REQUIRES: swift_feature_StrictConcurrency
+
+@preconcurrency @unsafe import unsafe_swift_decls
diff --git a/test/Unsafe/safe.swift b/test/Unsafe/safe.swift
index 439788892ee93..d8e9cf6b79420 100644
--- a/test/Unsafe/safe.swift
+++ b/test/Unsafe/safe.swift
@@ -68,17 +68,17 @@ func acceptP(_: some P) { }
 
 func testConformance(i: Int) {
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
-  acceptP(i) // expected-note{{@unsafe conformance of 'Int' to protocol 'P' involves unsafe code}}
+  acceptP(i) // expected-note{{'@unsafe' conformance of 'Int' to protocol 'P' involves unsafe code}}
 }
 
 func returnsOpaqueP() -> some P {
   5 // expected-warning{{expression uses unsafe constructs but is not marked with 'unsafe'}}
-  // expected-note@-1{{@unsafe conformance of 'Int' to protocol 'P' involves unsafe code}}
+  // expected-note@-1{{'@unsafe' conformance of 'Int' to protocol 'P' involves unsafe code}}
 }
 
 func returnsExistentialP() -> any P {
   5 // expected-warning{{expression uses unsafe constructs but is not marked with 'unsafe'}}
-  // expected-note@-1{{@unsafe conformance of 'Int' to protocol 'P' involves unsafe code}}
+  // expected-note@-1{{'@unsafe' conformance of 'Int' to protocol 'P' involves unsafe code}}
 }
 
 // FIXME: Should work even if the IteratorProtocol conformance is safe
@@ -89,13 +89,17 @@ struct UnsafeAsSequence: @unsafe Sequence, @unsafe IteratorProtocol {
 func testUnsafeAsSequenceForEach() {
   let uas = UnsafeAsSequence()
 
+  // expected-note@+2{{reference to unsafe instance method 'next()'}}
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{12-12=unsafe }}
   for _ in uas { } // expected-note{{conformance}}
   // expected-warning@-1{{for-in loop uses unsafe constructs but is not marked with 'unsafe'}}{{documentation-file=strict-memory-safety}}{{7-7=unsafe }}
 
+  // expected-note@+1{{reference to unsafe instance method 'next()'}}
   for _ in unsafe uas { } // expected-warning{{for-in loop uses unsafe constructs but is not marked with 'unsafe'}}{{documentation-file=strict-memory-safety}}{{7-7=unsafe }}
 
   for unsafe _ in unsafe uas { } // okay
+
+  for unsafe _ in [1, 2, 3] { } // expected-warning{{no unsafe operations occur within 'unsafe' for-in loop}}
 }
 
 func testForInUnsafeAmbiguity(_ integers: [Int]) {
@@ -118,6 +122,7 @@ struct SequenceWithUnsafeIterator: Sequence {
 func testUnsafeIteratorForEach() {
   let swui = SequenceWithUnsafeIterator()
 
+  // expected-note@+1{{reference to unsafe instance method 'next()'}}
   for _ in swui { } // expected-warning{{for-in loop uses unsafe constructs but is not marked with 'unsafe'}}{{7-7=unsafe }}
   for unsafe _ in swui { } // okay, it's only the iterator that's unsafe
 }
@@ -142,7 +147,7 @@ func casting(value: Any, i: Int) {
   _ = unsafe value as! UnsafeType
 
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
-  _ = i as any P // expected-note{{@unsafe conformance of 'Int' to protocol 'P' involves unsafe code}}
+  _ = i as any P // expected-note{{'@unsafe' conformance of 'Int' to protocol 'P' involves unsafe code}}
 }
 
 func metatypes() {
@@ -200,6 +205,8 @@ func unsafeFun() {
   _ = color
 
   if unsafe { }
+
+  _ = unsafe ? 1 : 0
 }
 
 func moreUnsafeFunc(unsafe: [Int]) {
@@ -218,6 +225,13 @@ func yetMoreUnsafeFunc(unsafe: () -> Void) {
   // expected-warning@-1{{no unsafe operations occur within 'unsafe' expression}}
 }
 
+func yetMoreMoreUnsafeFunc(unsafe: Int?) {
+  _ = unsafe!
+  if let unsafe {
+    _ = unsafe + 1
+  }
+}
+
 // @safe suppresses unsafe-type-related diagnostics on an entity
 struct MyArray<Element> {
   @safe func withUnsafeBufferPointer<R, E>(
@@ -270,4 +284,111 @@ struct UnsafeWrapTest {
 }
 
 @safe @unsafe
-struct ConfusedStruct { } // expected-error{{struct 'ConfusedStruct' cannot be both @safe and @unsafe}}
+struct ConfusedStruct { } // expected-error{{struct 'ConfusedStruct' cannot be both '@safe' and '@unsafe'}}
+
+@unsafe
+struct UnsafeContainingUnspecified {
+  typealias A = Int
+
+  func getA() -> A { 0 }
+
+  @safe
+  struct Y {
+    var value: Int
+  }
+
+  func f() {
+    _ = Y(value: 5)
+  }
+}
+
+
+@unsafe func f(x: UnsafeContainingUnspecified) {
+  let a = unsafe x.getA()
+  _ = a
+}
+
+extension Slice {
+  // Make sure we aren't diagnosing the 'defer' as unsafe.
+  public func withContiguousMutableStorageIfAvailable<R, Element>(
+    _ body: (_ buffer: inout UnsafeMutableBufferPointer<Element>) throws -> R
+  ) rethrows -> R? where Base == UnsafeMutableBufferPointer<Element> {
+    try unsafe base.withContiguousStorageIfAvailable { buffer in
+      let start = unsafe base.baseAddress?.advanced(by: startIndex)
+      var slice = unsafe UnsafeMutableBufferPointer(start: start, count: count)
+      defer {
+      }
+      return try unsafe body(&slice)
+    }
+  }
+}
+
+@unsafe enum SomeEnum {
+  case first
+  case second
+}
+
+@unsafe var someEnumValue: SomeEnum = unsafe .first
+
+func testSwitch(se: SomeEnum) {
+  switch unsafe se {
+  case unsafe someEnumValue: break
+  default: break
+  }
+
+  switch unsafe se {
+  case someEnumValue: break
+    // expected-warning@-1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{8-8=unsafe }}
+    // expected-note@-2{{argument #0 in call to operator function '~=' has unsafe type 'SomeEnum'}}
+    // expected-note@-3{{argument #1 in call to operator function '~=' has unsafe type 'SomeEnum'}}
+    // expected-note@-4{{reference to unsafe type 'SomeEnum'}}
+    // expected-note@-5{{reference to unsafe var 'someEnumValue'}}
+    // expected-note@-6{{reference to let '$match' involves unsafe type 'SomeEnum'}}
+  default: break
+  }
+
+  // expected-note@+2{{reference to parameter 'se' involves unsafe type 'SomeEnum'}}
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{10-10=unsafe }}
+  switch se {
+  case unsafe someEnumValue: break
+  default: break
+  }
+
+  if case someEnumValue = unsafe se { }
+    // expected-warning@-1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{11-11=unsafe }}
+    // expected-note@-2{{argument #0 in call to operator function '~=' has unsafe type 'SomeEnum'}}
+    // expected-note@-3{{argument #1 in call to operator function '~=' has unsafe type 'SomeEnum'}}
+    // expected-note@-4{{reference to unsafe type 'SomeEnum'}}
+    // expected-note@-5{{reference to unsafe var 'someEnumValue'}}
+    // expected-note@-6{{reference to let '$match' involves unsafe type 'SomeEnum'}}
+
+  if case unsafe someEnumValue = unsafe se { }
+}
+
+@unsafe class SomeClass {}
+@unsafe class SomeClassWrapper { }
+
+protocol Associated {
+    associatedtype Associated
+}
+
+protocol CustomAssociated: Associated { }
+
+// expected-warning@+1{{conformance of 'SomeClass' to protocol 'Associated' involves unsafe code}}{{22-22=@unsafe }}
+extension SomeClass: CustomAssociated {
+  typealias Associated = SomeClassWrapper // expected-note{{unsafe type 'SomeClass.Associated' (aka 'SomeClassWrapper') cannot satisfy safe associated type 'Associated'}}
+}
+
+func testInterpolation(ptr: UnsafePointer<Int>) {
+  _ = "Hello \(unsafe ptr)" // expected-warning{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{7-7=unsafe }}
+  // expected-note@-1{{reference to unsafe type 'UnsafePointer<Int>'}}
+  // expected-note@-2{{argument #0 in call to instance method 'appendInterpolation' has unsafe type 'UnsafePointer<Int>'}}
+  // expected-note@-3{{reference to instance method 'appendInterpolation' involves unsafe type 'UnsafePointer<Int>'}}
+}
+
+func superDuperUnsafe(_ bytes: UnsafeRawBufferPointer) {
+  // expected-warning@+1{{no unsafe operations occur within 'unsafe' expression}}
+  let byte = unsafe unsafe bytes.first ?? 0
+  _ = byte
+  _ = unsafe bytes.first ?? 0
+}
diff --git a/test/Unsafe/safe_argument_suppression.swift b/test/Unsafe/safe_argument_suppression.swift
index be01e143532f9..c6924cd73e234 100644
--- a/test/Unsafe/safe_argument_suppression.swift
+++ b/test/Unsafe/safe_argument_suppression.swift
@@ -38,7 +38,7 @@ class NotSafeSubclass: NotSafe {
 
   ns.stillUnsafe() // expected-warning{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{documentation-file=strict-memory-safety}}
   // expected-note@-1{{reference to parameter 'ns' involves unsafe type 'NotSafe'}}
-  // expected-note@-2{{reference to instance method 'stillUnsafe()' involves unsafe type 'NotSafe'}}
+  // expected-note@-2{{argument 'self' in call to instance method 'stillUnsafe' has unsafe type 'NotSafe'}}
 }
 
 @safe func testImpliedSafetySubclass(ns: NotSafeSubclass) {
diff --git a/test/Unsafe/unsafe-suppression.swift b/test/Unsafe/unsafe-suppression.swift
index b88981f7de328..07af6f17597a6 100644
--- a/test/Unsafe/unsafe-suppression.swift
+++ b/test/Unsafe/unsafe-suppression.swift
@@ -11,7 +11,10 @@ func iAmImpliedUnsafe() -> UnsafeType? { nil }
 @unsafe
 func labeledUnsafe(_: UnsafeType) {
   unsafe iAmUnsafe()
-  let _ = unsafe iAmImpliedUnsafe()
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
+  let _ = iAmImpliedUnsafe() // expected-note{{reference to global function 'iAmImpliedUnsafe()' involves unsafe type 'UnsafeType'}}
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
+  let _ = iAmImpliedUnsafe // expected-note{{reference to global function 'iAmImpliedUnsafe()' involves unsafe type 'UnsafeType'}}
 }
 
 
@@ -19,7 +22,7 @@ class C {
   func method() { } // expected-note{{overridden declaration is here}}
 }
 
-class D1: C { // expected-note{{make class 'D1' @unsafe to allow unsafe overrides of safe superclass methods}}{{1-1=@unsafe }}
+class D1: C { // expected-note{{make class 'D1' '@unsafe' to allow unsafe overrides of safe superclass methods}}{{1-1=@unsafe }}
   @unsafe
   override func method() { } // expected-warning{{override of safe instance method with unsafe instance method}}{{documentation-file=strict-memory-safety}}
 }
@@ -142,9 +145,12 @@ struct UnsafeSequence: @unsafe IteratorProtocol, @unsafe Sequence {
 }
 
 func forEachLoop(us: UnsafeSequence) {
+  // expected-note@+1{{reference to unsafe instance method 'next()'}}
   for _ in us { } // expected-warning{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{documentation-file=strict-memory-safety}}{{12-12=unsafe }}
-  // expected-note@-1{{@unsafe conformance of 'UnsafeSequence' to protocol 'Sequence' involves unsafe code}}
+  // expected-note@-1{{'@unsafe' conformance of 'UnsafeSequence' to protocol 'Sequence' involves unsafe code}}
   // expected-warning@-2{{for-in loop uses unsafe constructs but is not marked with 'unsafe'}}{{documentation-file=strict-memory-safety}}
+
+  // expected-note@+1{{reference to unsafe instance method 'next()'}}
   for _ in unsafe us { }
   // expected-warning@-1{{for-in loop uses unsafe constructs but is not marked with 'unsafe'}}{{documentation-file=strict-memory-safety}}
 }
diff --git a/test/Unsafe/unsafe.swift b/test/Unsafe/unsafe.swift
index fdb3d745ceae9..390b2c132c86b 100644
--- a/test/Unsafe/unsafe.swift
+++ b/test/Unsafe/unsafe.swift
@@ -49,7 +49,49 @@ extension ConformsToMultiP: MultiP {
   // expected-note@-1{{unsafe type 'UnsafeSuper' cannot satisfy safe associated type 'Ptr'}}
   @unsafe func f() -> UnsafeSuper {
     .init() // expected-warning{{expression uses unsafe constructs but is not marked with 'unsafe'}}
-    // expected-note@-1{{reference to initializer 'init()' involves unsafe type 'UnsafeSuper'}}
+    // expected-note@-1{{argument 'self' in call to initializer 'init' has unsafe type 'UnsafeSuper.Type'}}
+    // expected-note@-2{{reference to initializer 'init()' involves unsafe type 'UnsafeSuper'}}
+  }
+}
+
+// Make sure we correctly apply the conformance attribute for more complex
+// inheritance entries.
+do {
+  protocol SafeP {}
+  struct Nested {
+    protocol P { func f() }
+    protocol Q { func f() }
+  }
+  do {
+    // expected-warning@+1 {{conformance of 'S' to protocol 'P' involves unsafe code; use '@unsafe' to indicate that the conformance is not memory-safe}}{{15-15=@unsafe }}
+    struct S: Nested.P {
+      @unsafe func f() {}
+      // expected-note@-1 {{unsafe instance method 'f()' cannot satisfy safe requirement}}
+    }
+  }
+  do {
+    // Attribute inserted *before* 'nonisolated'.
+    struct S: nonisolated Nested.P {
+    // expected-warning@-1 {{conformance of 'S' to protocol 'P' involves unsafe code; use '@unsafe' to indicate that the conformance is not memory-safe}}{{15-15=@unsafe }}
+      @unsafe func f() {}
+      // expected-note@-1 {{unsafe instance method 'f()' cannot satisfy safe requirement}}
+    }
+  }
+  do {
+    // expected-warning@+2 {{conformance of 'S' to protocol 'P' involves unsafe code; use '@unsafe' to indicate that the conformance is not memory-safe}}{{15-15=@unsafe }}
+    // expected-warning@+1 {{conformance of 'S' to protocol 'Q' involves unsafe code; use '@unsafe' to indicate that the conformance is not memory-safe}}{{15-15=@unsafe }}
+    struct S: Nested.P & Nested.Q {
+      @unsafe func f() {}
+      // expected-note@-1 2 {{unsafe instance method 'f()' cannot satisfy safe requirement}}
+    }
+  }
+  do {
+    // FIXME: We shouldn't be applying nonisolated to both protocols.
+    // expected-warning@+1 {{conformance of 'S' to protocol 'P' involves unsafe code; use '@unsafe' to indicate that the conformance is not memory-safe}}{{15-15=@unsafe }}
+    struct S: Nested.P & SafeP {
+      @unsafe func f() {}
+      // expected-note@-1 {{unsafe instance method 'f()' cannot satisfy safe requirement}}
+    }
   }
 }
 
@@ -73,7 +115,7 @@ class Super {
   @unsafe func g() { }
 }
 
-class Sub: Super { // expected-note{{make class 'Sub' @unsafe to allow unsafe overrides of safe superclass methods}}{{1-1=@unsafe }}
+class Sub: Super { // expected-note{{make class 'Sub' '@unsafe' to allow unsafe overrides of safe superclass methods}}{{1-1=@unsafe }}
   @unsafe override func f() { } // expected-warning{{override of safe instance method with unsafe instance method}}{{documentation-file=strict-memory-safety}}
   @unsafe override func g() { }  
 }
@@ -104,9 +146,9 @@ class ExclusivityChecking {
 
   func next() -> Int {
     // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{5-5=unsafe }}
-    value += 1 // expected-note{{reference to @exclusivity(unchecked) property 'value' is unsafe}}
+    value += 1 // expected-note{{reference to '@exclusivity(unchecked)' property 'value' is unsafe}}
     // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{12-12=unsafe }}
-    return value  // expected-note{{reference to @exclusivity(unchecked) property 'value' is unsafe}}
+    return value  // expected-note{{reference to '@exclusivity(unchecked)' property 'value' is unsafe}}
   }
 }
 
@@ -141,11 +183,13 @@ func testRHS(b: Bool, x: Int) {
 }
 
 // -----------------------------------------------------------------------
-// Declaration references
+// Calls and declaration references
 // -----------------------------------------------------------------------
 @unsafe func unsafeF() { }
 @unsafe var unsafeVar: Int = 0
 
+func acceptUnsafeArgument(_: UnsafePointer<Int>?) { }
+func acceptUnsafeNamedArgument(arg: UnsafePointer<Int>?) { }
 
 func testMe(
   _ pointer: PointerType,
@@ -156,11 +200,29 @@ func testMe(
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{7-7=unsafe }}
   _ = unsafeVar // expected-note{{reference to unsafe var 'unsafeVar'}}
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{3-3=unsafe }}
-  unsafeSuper.f() // expected-note{{reference to instance method 'f()' involves unsafe type 'UnsafeSuper'}}
+  unsafeSuper.f() // expected-note{{argument 'self' in call to instance method 'f' has unsafe type 'UnsafeSuper'}}
   // expected-note@-1{{reference to parameter 'unsafeSuper' involves unsafe type 'UnsafeSuper'}}
 
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{7-7=unsafe }}
   _ = getPointers() // expected-note{{reference to global function 'getPointers()' involves unsafe type 'PointerType'}}
+
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{7-7=unsafe }}
+  _ = getPointers // expected-note{{reference to global function 'getPointers()' involves unsafe type 'PointerType'}}
+
+  var i = 17
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
+  acceptUnsafeArgument(&i) // expected-note{{argument #0 in call to global function 'acceptUnsafeArgument' has unsafe type 'UnsafePointer<Int>?'}}
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
+  acceptUnsafeNamedArgument(arg: &i) // expected-note{{argument 'arg' in call to global function 'acceptUnsafeNamedArgument' has unsafe type 'UnsafePointer<Int>?'}}
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
+  let fn: (UnsafePointer<Int>?) -> Void = acceptUnsafeArgument // expected-note{{reference to global function 'acceptUnsafeArgument' involves unsafe type 'UnsafePointer<Int>'}}
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
+  fn(&i) // expected-note{{argument #0 in call has unsafe type 'UnsafePointer<Int>?'}}
+
+  // Nil isn't unsafe
+  acceptUnsafeArgument(nil)
+  acceptUnsafeNamedArgument(arg: nil)
+  fn(nil)
 }
 
 // -----------------------------------------------------------------------
diff --git a/test/Unsafe/unsafe_concurrency.swift b/test/Unsafe/unsafe_concurrency.swift
index 761cbb6ca2155..895c62cdd816f 100644
--- a/test/Unsafe/unsafe_concurrency.swift
+++ b/test/Unsafe/unsafe_concurrency.swift
@@ -6,7 +6,7 @@
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_StrictConcurrency
 
-@preconcurrency import unsafe_swift_decls // expected-warning{{@preconcurrency import is not memory-safe because it can silently introduce data races}}
+@preconcurrency import unsafe_swift_decls // expected-warning{{'@preconcurrency' import is not memory-safe because it can silently introduce data races}}
 
 class C: @unchecked Sendable {
   var counter: Int = 0
@@ -55,3 +55,10 @@ open class SyntaxVisitor {
 open class SyntaxAnyVisitor: SyntaxVisitor {
   override open func visit(_ token: TokenSyntax) { }
 }
+
+@available(SwiftStdlib 5.1, *)
+func testMemorySafetyWithForLoop() async {
+  let (stream, continuation) = AsyncStream<Int>.makeStream()
+  for await _ in stream {}
+  _ = continuation
+}
diff --git a/test/Unsafe/unsafe_imports.swift b/test/Unsafe/unsafe_imports.swift
index f02db8b56e505..c227713d56248 100644
--- a/test/Unsafe/unsafe_imports.swift
+++ b/test/Unsafe/unsafe_imports.swift
@@ -13,7 +13,10 @@ func testUnsafe(_ ut: UnsafeType) {
   var array: [CInt] = [1, 2, 3, 4, 5]
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{3-3=unsafe }}
   print_ints(&array, CInt(array.count))
-  // expected-note@-1{{reference to global function 'print_ints' involves unsafe type 'UnsafeMutablePointer<Int32>'}}
+  // expected-note@-1{{argument #0 in call to global function 'print_ints' has unsafe type 'UnsafeMutablePointer<Int32>?'}}
+
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{7-7=unsafe }}
+  _ = print_ints // expected-note{{reference to global function 'print_ints' involves unsafe type 'UnsafeMutablePointer<Int32>'}}
 }
 
 // Reference a typealias that isn't itself @unsafe, but refers to an unsafe
@@ -25,7 +28,7 @@ func testUnsafeThroughAlias(_ ut: UnsafeTypeAlias) {
 
 func callThroughAlias(ut: UnsafeTypeAlias) {
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}
-  testUnsafeThroughAlias(ut) // expected-note{{reference to global function 'testUnsafeThroughAlias' involves unsafe type 'UnsafeTypeAlias' (aka 'PointerType')}}
+  testUnsafeThroughAlias(ut) // expected-note{{argument #0 in call to global function 'testUnsafeThroughAlias' has unsafe type 'UnsafeTypeAlias' (aka 'PointerType')}}
   // expected-note@-1{{reference to parameter 'ut' involves unsafe type 'UnsafeTypeAlias' (aka 'PointerType')}}
 }
 
diff --git a/test/Unsafe/unsafe_nonstrict.swift b/test/Unsafe/unsafe_nonstrict.swift
index 3b91c22f000ee..8457a8999e8ac 100644
--- a/test/Unsafe/unsafe_nonstrict.swift
+++ b/test/Unsafe/unsafe_nonstrict.swift
@@ -14,5 +14,12 @@ func acceptP<T: P>(_: T) { }
 func testItAll(ut: UnsafeType, x: X, i: Int) {
   _ = unsafe ut
   unsafe acceptP(x)
-  _ = unsafe i
+  _ = unsafe i // expected-warning{{no unsafe operations occur within 'unsafe' expression}}
+}
+
+func superDuperUnsafe(_ bytes: UnsafeRawBufferPointer) {
+  // expected-warning@+1{{no unsafe operations occur within 'unsafe' expression}}
+  let byte = unsafe unsafe bytes.first ?? 0
+  _ = byte
+  _ = unsafe bytes.first ?? 0
 }
diff --git a/test/Unsafe/unsafe_stdlib.swift b/test/Unsafe/unsafe_stdlib.swift
index 08bd0e26f859e..e164a0d65c75c 100644
--- a/test/Unsafe/unsafe_stdlib.swift
+++ b/test/Unsafe/unsafe_stdlib.swift
@@ -8,7 +8,8 @@ func test(
   other: UnsafeMutablePointer<Int>
 ) {
   var array = [1, 2, 3]
-  // expected-warning@+2{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{3-3=unsafe }}
+  // expected-warning@+3{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{3-3=unsafe }}
+  // expected-note@+2{{argument #0 in call to instance method 'withUnsafeBufferPointer' has unsafe type '(UnsafeBufferPointer<Int>) -> ()'}}
   // expected-note@+1{{reference to instance method 'withUnsafeBufferPointer' involves unsafe type 'UnsafeBufferPointer<Int>'}}
   array.withUnsafeBufferPointer{ buffer in
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{5-5=unsafe }}
diff --git a/test/abi/Inputs/macOS/arm64/concurrency/baseline b/test/abi/Inputs/macOS/arm64/concurrency/baseline
index 557c626a2cada..9f91995fd1839 100644
--- a/test/abi/Inputs/macOS/arm64/concurrency/baseline
+++ b/test/abi/Inputs/macOS/arm64/concurrency/baseline
@@ -25,6 +25,8 @@ _$sScEN
 _$sScEs5ErrorsMc
 _$sScF14isMainExecutorSbvgTj
 _$sScF14isMainExecutorSbvgTq
+_$sScF20asSchedulingExecutors0bC0_pSgvgTj
+_$sScF20asSchedulingExecutors0bC0_pSgvgTq
 _$sScF7enqueueyyScJFTj
 _$sScF7enqueueyyScJFTq
 _$sScF7enqueueyys11ExecutorJobVnFTj
@@ -37,6 +39,8 @@ _$sScFsE14isMainExecutorSbvg
 _$sScFsE14isMainExecutorSbvpMV
 _$sScFsE18_isComplexEqualitySbvg
 _$sScFsE18_isComplexEqualitySbvpMV
+_$sScFsE20asSchedulingExecutors0bC0_pSgvg
+_$sScFsE20asSchedulingExecutors0bC0_pSgvpMV
 _$sScFsE7enqueueyyScJF
 _$sScFsE7enqueueyys11ExecutorJobVnF
 _$sScFsE7enqueueyys3JobVnF
@@ -164,12 +168,18 @@ _$sScS12ContinuationV15BufferingPolicyO15bufferingOldestyADyx__GSicAFmlFWC
 _$sScS12ContinuationV15BufferingPolicyO9unboundedyADyx__GAFmlFWC
 _$sScS12ContinuationV15BufferingPolicyOMa
 _$sScS12ContinuationV15BufferingPolicyOMn
+_$sScS12ContinuationV2eeoiySbAByx_G_ADtFZ
+_$sScS12ContinuationV4hash4intoys6HasherVz_tF
 _$sScS12ContinuationV5yield4withAB11YieldResultOyx__Gs0E0Oyxs5NeverOG_tF
 _$sScS12ContinuationV5yieldAB11YieldResultOyyt__GyytRszlF
 _$sScS12ContinuationV5yieldyAB11YieldResultOyx__GxnF
 _$sScS12ContinuationV6finishyyF
+_$sScS12ContinuationV9hashValueSivg
+_$sScS12ContinuationV9hashValueSivpMV
 _$sScS12ContinuationVMa
 _$sScS12ContinuationVMn
+_$sScS12ContinuationVyx_GSHsMc
+_$sScS12ContinuationVyx_GSQsMc
 _$sScS17makeAsyncIteratorScS0C0Vyx_GyF
 _$sScS8IteratorV4nextxSgyYaF
 _$sScS8IteratorV4nextxSgyYaFTu
@@ -213,8 +223,8 @@ _$sScTss5NeverORszABRs_rlE15defaultExecutorSch_pvpZMV
 _$sScTss5NeverORszABRs_rlE17checkCancellationyyKFZ
 _$sScTss5NeverORszABRs_rlE17preferredExecutorSch_pSgvgZ
 _$sScTss5NeverORszABRs_rlE17preferredExecutorSch_pSgvpZMV
-_$sScTss5NeverORszABRs_rlE26currentSchedulableExecutors0cD0_pSgvgZ
-_$sScTss5NeverORszABRs_rlE26currentSchedulableExecutors0cD0_pSgvpZMV
+_$sScTss5NeverORszABRs_rlE25currentSchedulingExecutors0cD0_pSgvgZ
+_$sScTss5NeverORszABRs_rlE25currentSchedulingExecutors0cD0_pSgvpZMV
 _$sScTss5NeverORszABRs_rlE5sleep11nanosecondsys6UInt64V_tYaKFZ
 _$sScTss5NeverORszABRs_rlE5sleep11nanosecondsys6UInt64V_tYaKFZTu
 _$sScTss5NeverORszABRs_rlE5sleep5until9tolerance5clocky7InstantQyd___8DurationQyd__Sgqd__tYaKs5ClockRd__lFZ
@@ -359,12 +369,18 @@ _$sScs12ContinuationV15BufferingPolicyO15bufferingOldestyADyxq___GSicAFms5ErrorR
 _$sScs12ContinuationV15BufferingPolicyO9unboundedyADyxq___GAFms5ErrorR_r0_lFWC
 _$sScs12ContinuationV15BufferingPolicyOMa
 _$sScs12ContinuationV15BufferingPolicyOMn
+_$sScs12ContinuationV2eeoiySbAByxq__G_ADtFZ
+_$sScs12ContinuationV4hash4intoys6HasherVz_tF
 _$sScs12ContinuationV5yield4withAB11YieldResultOyxs5Error_p__Gs0E0OyxsAG_pG_tsAG_pRs_rlF
 _$sScs12ContinuationV5yieldAB11YieldResultOyytq___GyytRszrlF
 _$sScs12ContinuationV5yieldyAB11YieldResultOyxq___GxnF
 _$sScs12ContinuationV6finish8throwingyq_Sgn_tF
+_$sScs12ContinuationV9hashValueSivg
+_$sScs12ContinuationV9hashValueSivpMV
 _$sScs12ContinuationVMa
 _$sScs12ContinuationVMn
+_$sScs12ContinuationVyxq__GSHsMc
+_$sScs12ContinuationVyxq__GSQsMc
 _$sScs17makeAsyncIteratorScs0C0Vyxq__GyF
 _$sScs8IteratorV4nextxSgyYaKF
 _$sScs8IteratorV4nextxSgyYaKFTu
@@ -393,23 +409,6 @@ _$sSctN
 _$sSctSHsMc
 _$sSctSQsMc
 _$ss039_checkIllegalTaskLocalBindingWithinWithC5Group4file4lineySS_SutF
-_$ss11ClockTraitsV10continuousABvgZ
-_$ss11ClockTraitsV10continuousABvpZMV
-_$ss11ClockTraitsV8rawValueABs6UInt32V_tcfC
-_$ss11ClockTraitsV8rawValues6UInt32Vvg
-_$ss11ClockTraitsV8rawValues6UInt32VvpMV
-_$ss11ClockTraitsV8wallTimeABvgZ
-_$ss11ClockTraitsV8wallTimeABvpZMV
-_$ss11ClockTraitsV9monotonicABvgZ
-_$ss11ClockTraitsV9monotonicABvpZMV
-_$ss11ClockTraitsVMa
-_$ss11ClockTraitsVMn
-_$ss11ClockTraitsVN
-_$ss11ClockTraitsVSQsMc
-_$ss11ClockTraitsVSYsMc
-_$ss11ClockTraitsVs10SetAlgebrasMc
-_$ss11ClockTraitsVs25ExpressibleByArrayLiteralsMc
-_$ss11ClockTraitsVs9OptionSetsMc
 _$ss11ExecutorJobV010withUnsafeA11PrivateData4bodyxxSwq_YKXE_tq_YKs5ErrorR_r0_lF
 _$ss11ExecutorJobV11descriptionSSvg
 _$ss11ExecutorJobV14LocalAllocatorV10deallocateyySpyxGlF
@@ -421,6 +420,7 @@ _$ss11ExecutorJobV14LocalAllocatorV8allocate8capacitySwSi_tF
 _$ss11ExecutorJobV14LocalAllocatorVMa
 _$ss11ExecutorJobV14LocalAllocatorVMn
 _$ss11ExecutorJobV14LocalAllocatorVN
+_$ss11ExecutorJobV16createTrampoline2toABx_tScFRzlF
 _$ss11ExecutorJobV4KindV13firstReservedADvgZ
 _$ss11ExecutorJobV4KindV13firstReservedADvpZMV
 _$ss11ExecutorJobV4KindV4taskADvgZ
@@ -459,6 +459,7 @@ _$ss11JobPriorityV2eeoiySbAB_ABtFZ
 _$ss11JobPriorityV2geoiySbAB_ABtFZ
 _$ss11JobPriorityV2leoiySbAB_ABtFZ
 _$ss11JobPriorityV2neoiySbAB_ABtFZ
+_$ss11JobPriorityV8rawValueABs5UInt8V_tcfC
 _$ss11JobPriorityV8rawValues5UInt8VvM
 _$ss11JobPriorityV8rawValues5UInt8Vvg
 _$ss11JobPriorityV8rawValues5UInt8VvpMV
@@ -468,6 +469,7 @@ _$ss11JobPriorityVMn
 _$ss11JobPriorityVN
 _$ss11JobPriorityVSLsMc
 _$ss11JobPriorityVSQsMc
+_$ss11JobPriorityVyABScPcfC
 _$ss12MainExecutorMp
 _$ss12MainExecutorPScfTb
 _$ss12MainExecutorPs07RunLoopB0Tb
@@ -475,35 +477,14 @@ _$ss12MainExecutorTL
 _$ss13_runAsyncMainyyyyYaKcF
 _$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lF
 _$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lFTu
-_$ss14CFMainExecutorC3runyyKF
-_$ss14CFMainExecutorC4stopyyF
-_$ss14CFMainExecutorCABycfC
-_$ss14CFMainExecutorCABycfc
-_$ss14CFMainExecutorCMa
-_$ss14CFMainExecutorCMm
-_$ss14CFMainExecutorCMn
-_$ss14CFMainExecutorCMo
-_$ss14CFMainExecutorCN
-_$ss14CFMainExecutorCfD
-_$ss14CFMainExecutorCfd
-_$ss14CFTaskExecutorCABycfC
-_$ss14CFTaskExecutorCABycfc
-_$ss14CFTaskExecutorCMa
-_$ss14CFTaskExecutorCMm
-_$ss14CFTaskExecutorCMn
-_$ss14CFTaskExecutorCMo
-_$ss14CFTaskExecutorCN
-_$ss14CFTaskExecutorCfD
-_$ss14CFTaskExecutorCfd
 _$ss15ContinuousClockV17minimumResolutions8DurationVvg
 _$ss15ContinuousClockV17minimumResolutions8DurationVvpMV
 _$ss15ContinuousClockV3nowAB7InstantVvg
 _$ss15ContinuousClockV3nowAB7InstantVvgZ
 _$ss15ContinuousClockV3nowAB7InstantVvpMV
+_$ss15ContinuousClockV3run_2at9toleranceys11ExecutorJobVn_AB7InstantVs8DurationVSgtF
 _$ss15ContinuousClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKF
 _$ss15ContinuousClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKFTu
-_$ss15ContinuousClockV6traitss0B6TraitsVvg
-_$ss15ContinuousClockV6traitss0B6TraitsVvpMV
 _$ss15ContinuousClockV7InstantV1loiySbAD_ADtFZ
 _$ss15ContinuousClockV7InstantV2eeoiySbAD_ADtFZ
 _$ss15ContinuousClockV7InstantV3nowADvgZ
@@ -523,6 +504,7 @@ _$ss15ContinuousClockV7InstantVSLsMc
 _$ss15ContinuousClockV7InstantVSQsMc
 _$ss15ContinuousClockV7InstantVSesMc
 _$ss15ContinuousClockV7InstantVs0C8ProtocolsMc
+_$ss15ContinuousClockV7enqueue_2on2at9toleranceys11ExecutorJobVn_xAB7InstantVs8DurationVSgtScFRzlF
 _$ss15ContinuousClockVABycfC
 _$ss15ContinuousClockVMa
 _$ss15ContinuousClockVMn
@@ -550,10 +532,9 @@ _$ss15SuspendingClockV17minimumResolutions8DurationVvpMV
 _$ss15SuspendingClockV3nowAB7InstantVvg
 _$ss15SuspendingClockV3nowAB7InstantVvgZ
 _$ss15SuspendingClockV3nowAB7InstantVvpMV
+_$ss15SuspendingClockV3run_2at9toleranceys11ExecutorJobVn_AB7InstantVs8DurationVSgtF
 _$ss15SuspendingClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKF
 _$ss15SuspendingClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKFTu
-_$ss15SuspendingClockV6traitss0B6TraitsVvg
-_$ss15SuspendingClockV6traitss0B6TraitsVvpMV
 _$ss15SuspendingClockV7InstantV1loiySbAD_ADtFZ
 _$ss15SuspendingClockV7InstantV1poiyA2D_s8DurationVtFZ
 _$ss15SuspendingClockV7InstantV1soiyA2D_s8DurationVtFZ
@@ -578,6 +559,7 @@ _$ss15SuspendingClockV7InstantVSLsMc
 _$ss15SuspendingClockV7InstantVSQsMc
 _$ss15SuspendingClockV7InstantVSesMc
 _$ss15SuspendingClockV7InstantVs0C8ProtocolsMc
+_$ss15SuspendingClockV7enqueue_2on2at9toleranceys11ExecutorJobVn_xAB7InstantVs8DurationVSgtScFRzlF
 _$ss15SuspendingClockVABycfC
 _$ss15SuspendingClockVMa
 _$ss15SuspendingClockVMn
@@ -605,51 +587,15 @@ _$ss16AsyncMapSequenceVMa
 _$ss16AsyncMapSequenceVMn
 _$ss16AsyncMapSequenceV_9transformAByxq_Gx_q_7ElementQzYactcfC
 _$ss16AsyncMapSequenceVyxq_GScisMc
-_$ss17DummyMainExecutorC02isbC0Sbvg
-_$ss17DummyMainExecutorC02isbC0SbvpMV
-_$ss17DummyMainExecutorC13checkIsolatedyyF
-_$ss17DummyMainExecutorC3runyyKF
-_$ss17DummyMainExecutorC4stopyyF
-_$ss17DummyMainExecutorC7enqueueyys0C3JobVnF
-_$ss17DummyMainExecutorCABycfC
-_$ss17DummyMainExecutorCABycfCTj
-_$ss17DummyMainExecutorCABycfCTq
-_$ss17DummyMainExecutorCABycfc
-_$ss17DummyMainExecutorCMa
-_$ss17DummyMainExecutorCMm
-_$ss17DummyMainExecutorCMn
-_$ss17DummyMainExecutorCMo
-_$ss17DummyMainExecutorCMu
-_$ss17DummyMainExecutorCN
-_$ss17DummyMainExecutorCScFsMc
-_$ss17DummyMainExecutorCScFsWP
-_$ss17DummyMainExecutorCScfsMc
-_$ss17DummyMainExecutorCScfsWP
-_$ss17DummyMainExecutorCfD
-_$ss17DummyMainExecutorCfd
-_$ss17DummyMainExecutorCs07RunLoopC0sMc
-_$ss17DummyMainExecutorCs07RunLoopC0sWP
-_$ss17DummyMainExecutorCs0bC0sMc
-_$ss17DummyMainExecutorCs0bC0sWP
-_$ss17DummyTaskExecutorC06isMainC0Sbvg
-_$ss17DummyTaskExecutorC06isMainC0SbvpMV
-_$ss17DummyTaskExecutorC7enqueueyys0C3JobVnF
-_$ss17DummyTaskExecutorCABycfC
-_$ss17DummyTaskExecutorCABycfCTj
-_$ss17DummyTaskExecutorCABycfCTq
-_$ss17DummyTaskExecutorCABycfc
-_$ss17DummyTaskExecutorCMa
-_$ss17DummyTaskExecutorCMm
-_$ss17DummyTaskExecutorCMn
-_$ss17DummyTaskExecutorCMo
-_$ss17DummyTaskExecutorCMu
-_$ss17DummyTaskExecutorCN
-_$ss17DummyTaskExecutorCScFsMc
-_$ss17DummyTaskExecutorCScFsWP
-_$ss17DummyTaskExecutorCSchsMc
-_$ss17DummyTaskExecutorCSchsWP
-_$ss17DummyTaskExecutorCfD
-_$ss17DummyTaskExecutorCfd
+_$ss18SchedulingExecutorMp
+_$ss18SchedulingExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTj
+_$ss18SchedulingExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTq
+_$ss18SchedulingExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTj
+_$ss18SchedulingExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTq
+_$ss18SchedulingExecutorPScFTb
+_$ss18SchedulingExecutorPsE7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lF
+_$ss18SchedulingExecutorPsE7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lF
+_$ss18SchedulingExecutorTL
 _$ss19AsyncFilterSequenceV04makeA8IteratorAB0E0Vyx_GyF
 _$ss19AsyncFilterSequenceV10isIncludedySb7ElementQzYacvg
 _$ss19AsyncFilterSequenceV10isIncludedySb7ElementQzYacvpMV
@@ -707,15 +653,6 @@ _$ss19DiscardingTaskGroupV9cancelAllyyF
 _$ss19DiscardingTaskGroupVMa
 _$ss19DiscardingTaskGroupVMn
 _$ss19DiscardingTaskGroupVN
-_$ss19SchedulableExecutorMp
-_$ss19SchedulableExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTj
-_$ss19SchedulableExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTq
-_$ss19SchedulableExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTj
-_$ss19SchedulableExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTq
-_$ss19SchedulableExecutorPScFTb
-_$ss19SchedulableExecutorPsE7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lF
-_$ss19SchedulableExecutorPsE7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lF
-_$ss19SchedulableExecutorTL
 _$ss19UnownedTaskExecutorV02asbC0Sch_pSgyF
 _$ss19UnownedTaskExecutorVyABxhcSchRzlufC
 _$ss20AsyncFlatMapSequenceV04makeA8IteratorAB0F0Vyxq__GyF
@@ -747,39 +684,6 @@ _$ss20AsyncFlatMapSequenceVMa
 _$ss20AsyncFlatMapSequenceVMn
 _$ss20AsyncFlatMapSequenceV_9transformAByxq_Gx_q_7ElementQzYactcfC
 _$ss20AsyncFlatMapSequenceVyxq_GScisMc
-_$ss20DispatchMainExecutorC02isbC0Sbvg
-_$ss20DispatchMainExecutorC02isbC0SbvpMV
-_$ss20DispatchMainExecutorC13asSchedulables0eC0_pSgvg
-_$ss20DispatchMainExecutorC13asSchedulables0eC0_pSgvpMV
-_$ss20DispatchMainExecutorC13checkIsolatedyyF
-_$ss20DispatchMainExecutorC3runyyKFTj
-_$ss20DispatchMainExecutorC3runyyKFTq
-_$ss20DispatchMainExecutorC4stopyyFTj
-_$ss20DispatchMainExecutorC4stopyyFTq
-_$ss20DispatchMainExecutorC7enqueue_2at9tolerance5clockys0C3JobVn_7InstantQz8DurationQzSgxts5ClockRzlF
-_$ss20DispatchMainExecutorC7enqueueyys0C3JobVnF
-_$ss20DispatchMainExecutorCABycfC
-_$ss20DispatchMainExecutorCABycfCTj
-_$ss20DispatchMainExecutorCABycfCTq
-_$ss20DispatchMainExecutorCABycfc
-_$ss20DispatchMainExecutorCMa
-_$ss20DispatchMainExecutorCMm
-_$ss20DispatchMainExecutorCMn
-_$ss20DispatchMainExecutorCMo
-_$ss20DispatchMainExecutorCMu
-_$ss20DispatchMainExecutorCN
-_$ss20DispatchMainExecutorCScFsMc
-_$ss20DispatchMainExecutorCScFsWP
-_$ss20DispatchMainExecutorCScfsMc
-_$ss20DispatchMainExecutorCScfsWP
-_$ss20DispatchMainExecutorCfD
-_$ss20DispatchMainExecutorCfd
-_$ss20DispatchMainExecutorCs011SchedulableC0sMc
-_$ss20DispatchMainExecutorCs011SchedulableC0sWP
-_$ss20DispatchMainExecutorCs07RunLoopC0sMc
-_$ss20DispatchMainExecutorCs07RunLoopC0sWP
-_$ss20DispatchMainExecutorCs0bC0sMc
-_$ss20DispatchMainExecutorCs0bC0sWP
 _$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lF
 _$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lFTu
 _$ss21withUnsafeCurrentTask4bodyxxSctSgKXE_tKlF
@@ -915,31 +819,51 @@ _$ss24AsyncThrowingMapSequenceVMa
 _$ss24AsyncThrowingMapSequenceVMn
 _$ss24AsyncThrowingMapSequenceV_9transformAByxq_Gx_q_7ElementQzYaKctcfC
 _$ss24AsyncThrowingMapSequenceVyxq_GScisMc
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvgTj
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvgTq
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvpMV
-_$ss26DispatchGlobalTaskExecutorC7enqueue_2at9tolerance5clockys0D3JobVn_7InstantQz8DurationQzSgxts5ClockRzlFTj
-_$ss26DispatchGlobalTaskExecutorC7enqueue_2at9tolerance5clockys0D3JobVn_7InstantQz8DurationQzSgxts5ClockRzlFTq
-_$ss26DispatchGlobalTaskExecutorC7enqueueyys0D3JobVnFTj
-_$ss26DispatchGlobalTaskExecutorC7enqueueyys0D3JobVnFTq
-_$ss26DispatchGlobalTaskExecutorCABycfC
-_$ss26DispatchGlobalTaskExecutorCABycfCTj
-_$ss26DispatchGlobalTaskExecutorCABycfCTq
-_$ss26DispatchGlobalTaskExecutorCABycfc
-_$ss26DispatchGlobalTaskExecutorCMa
-_$ss26DispatchGlobalTaskExecutorCMm
-_$ss26DispatchGlobalTaskExecutorCMn
-_$ss26DispatchGlobalTaskExecutorCMo
-_$ss26DispatchGlobalTaskExecutorCMu
-_$ss26DispatchGlobalTaskExecutorCN
-_$ss26DispatchGlobalTaskExecutorCScFsMc
-_$ss26DispatchGlobalTaskExecutorCScFsWP
-_$ss26DispatchGlobalTaskExecutorCSchsMc
-_$ss26DispatchGlobalTaskExecutorCSchsWP
-_$ss26DispatchGlobalTaskExecutorCfD
-_$ss26DispatchGlobalTaskExecutorCfd
-_$ss26DispatchGlobalTaskExecutorCs011SchedulableD0sMc
-_$ss26DispatchGlobalTaskExecutorCs011SchedulableD0sWP
+_$ss25UnimplementedMainExecutorC02isbC0Sbvg
+_$ss25UnimplementedMainExecutorC02isbC0SbvpMV
+_$ss25UnimplementedMainExecutorC13checkIsolatedyyF
+_$ss25UnimplementedMainExecutorC3runyyKF
+_$ss25UnimplementedMainExecutorC4stopyyF
+_$ss25UnimplementedMainExecutorC7enqueueyys0C3JobVnF
+_$ss25UnimplementedMainExecutorCABycfC
+_$ss25UnimplementedMainExecutorCABycfCTj
+_$ss25UnimplementedMainExecutorCABycfCTq
+_$ss25UnimplementedMainExecutorCABycfc
+_$ss25UnimplementedMainExecutorCMa
+_$ss25UnimplementedMainExecutorCMm
+_$ss25UnimplementedMainExecutorCMn
+_$ss25UnimplementedMainExecutorCMo
+_$ss25UnimplementedMainExecutorCMu
+_$ss25UnimplementedMainExecutorCN
+_$ss25UnimplementedMainExecutorCScFsMc
+_$ss25UnimplementedMainExecutorCScFsWP
+_$ss25UnimplementedMainExecutorCScfsMc
+_$ss25UnimplementedMainExecutorCScfsWP
+_$ss25UnimplementedMainExecutorCfD
+_$ss25UnimplementedMainExecutorCfd
+_$ss25UnimplementedMainExecutorCs07RunLoopC0sMc
+_$ss25UnimplementedMainExecutorCs07RunLoopC0sWP
+_$ss25UnimplementedMainExecutorCs0bC0sMc
+_$ss25UnimplementedMainExecutorCs0bC0sWP
+_$ss25UnimplementedTaskExecutorC06isMainC0Sbvg
+_$ss25UnimplementedTaskExecutorC06isMainC0SbvpMV
+_$ss25UnimplementedTaskExecutorC7enqueueyys0C3JobVnF
+_$ss25UnimplementedTaskExecutorCABycfC
+_$ss25UnimplementedTaskExecutorCABycfCTj
+_$ss25UnimplementedTaskExecutorCABycfCTq
+_$ss25UnimplementedTaskExecutorCABycfc
+_$ss25UnimplementedTaskExecutorCMa
+_$ss25UnimplementedTaskExecutorCMm
+_$ss25UnimplementedTaskExecutorCMn
+_$ss25UnimplementedTaskExecutorCMo
+_$ss25UnimplementedTaskExecutorCMu
+_$ss25UnimplementedTaskExecutorCN
+_$ss25UnimplementedTaskExecutorCScFsMc
+_$ss25UnimplementedTaskExecutorCScFsWP
+_$ss25UnimplementedTaskExecutorCSchsMc
+_$ss25UnimplementedTaskExecutorCSchsWP
+_$ss25UnimplementedTaskExecutorCfD
+_$ss25UnimplementedTaskExecutorCfd
 _$ss27AsyncThrowingFilterSequenceV04makeA8IteratorAB0F0Vyx_GyF
 _$ss27AsyncThrowingFilterSequenceV10isIncludedySb7ElementQzYaKcvg
 _$ss27AsyncThrowingFilterSequenceV10isIncludedySb7ElementQzYaKcvpMV
@@ -1104,29 +1028,21 @@ _$ss5ClockP17minimumResolution8DurationQzvgTj
 _$ss5ClockP17minimumResolution8DurationQzvgTq
 _$ss5ClockP3now7InstantQzvgTj
 _$ss5ClockP3now7InstantQzvgTq
+_$ss5ClockP3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtFTj
+_$ss5ClockP3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtFTq
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTj
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTjTu
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTq
-_$ss5ClockP6traitss0A6TraitsVvgTj
-_$ss5ClockP6traitss0A6TraitsVvgTq
 _$ss5ClockP7InstantAB_s0B8ProtocolTn
-_$ss5ClockP7convert4from8DurationQzSgsAEV_tFTj
-_$ss5ClockP7convert4from8DurationQzSgsAEV_tFTq
-_$ss5ClockP7convert4froms8DurationVSgAEQz_tFTj
-_$ss5ClockP7convert4froms8DurationVSgAEQz_tFTq
-_$ss5ClockP7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lFTj
-_$ss5ClockP7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lFTq
-_$ss5ClockPsE6traitss0A6TraitsVvg
-_$ss5ClockPsE6traitss0A6TraitsVvpMV
-_$ss5ClockPsE7convert4from8DurationQzSgsAEV_tF
-_$ss5ClockPsE7convert4froms8DurationVSgAEQz_tF
-_$ss5ClockPsE7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lF
+_$ss5ClockP7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lFTj
+_$ss5ClockP7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lFTq
+_$ss5ClockPsE3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtF
+_$ss5ClockPsE7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lF
 _$ss5ClockPsE7measurey8DurationQzyyKXEKF
 _$ss5ClockPsE7measurey8DurationQzyyYaKXEYaKF
 _$ss5ClockPsE7measurey8DurationQzyyYaKXEYaKFTu
 _$ss5ClockPss010ContinuousA0VRszrlE10continuousADvgZ
 _$ss5ClockPss010SuspendingA0VRszrlE10suspendingADvgZ
-_$ss5ClockPss8DurationVACRtzrlE7convert4fromADSgAD_tF
 _$ss5ClockTL
 _$ss6_first_5where7ElementQzSgx_SbADYaKXEtYaKSciRzlF
 _$ss6_first_5where7ElementQzSgx_SbADYaKXEtYaKSciRzlFTu
@@ -1160,6 +1076,7 @@ _$ss9TaskLocalCyxGs23CustomStringConvertiblesMc
 _$ss9_contains_5whereSbx_Sb7ElementQzYaKXEtYaKSciRzlF
 _$ss9_contains_5whereSbx_Sb7ElementQzYaKXEtYaKSciRzlFTu
 __swift_concurrency_debug_asyncTaskMetadata
+__swift_concurrency_debug_asyncTaskSize
 __swift_concurrency_debug_asyncTaskSlabMetadata
 __swift_concurrency_debug_future_adapter
 __swift_concurrency_debug_jobMetadata
@@ -1167,6 +1084,7 @@ __swift_concurrency_debug_non_future_adapter
 __swift_concurrency_debug_supportsPriorityEscalation
 __swift_concurrency_debug_task_future_wait_resume_adapter
 __swift_concurrency_debug_task_wait_throwing_resume_adapter
+__swift_createJobForTestingOnly
 _swift_asyncLet_begin
 _swift_asyncLet_consume
 _swift_asyncLet_consume_throwing
diff --git a/test/abi/Inputs/macOS/arm64/concurrency/baseline-asserts b/test/abi/Inputs/macOS/arm64/concurrency/baseline-asserts
index 557c626a2cada..9f91995fd1839 100644
--- a/test/abi/Inputs/macOS/arm64/concurrency/baseline-asserts
+++ b/test/abi/Inputs/macOS/arm64/concurrency/baseline-asserts
@@ -25,6 +25,8 @@ _$sScEN
 _$sScEs5ErrorsMc
 _$sScF14isMainExecutorSbvgTj
 _$sScF14isMainExecutorSbvgTq
+_$sScF20asSchedulingExecutors0bC0_pSgvgTj
+_$sScF20asSchedulingExecutors0bC0_pSgvgTq
 _$sScF7enqueueyyScJFTj
 _$sScF7enqueueyyScJFTq
 _$sScF7enqueueyys11ExecutorJobVnFTj
@@ -37,6 +39,8 @@ _$sScFsE14isMainExecutorSbvg
 _$sScFsE14isMainExecutorSbvpMV
 _$sScFsE18_isComplexEqualitySbvg
 _$sScFsE18_isComplexEqualitySbvpMV
+_$sScFsE20asSchedulingExecutors0bC0_pSgvg
+_$sScFsE20asSchedulingExecutors0bC0_pSgvpMV
 _$sScFsE7enqueueyyScJF
 _$sScFsE7enqueueyys11ExecutorJobVnF
 _$sScFsE7enqueueyys3JobVnF
@@ -164,12 +168,18 @@ _$sScS12ContinuationV15BufferingPolicyO15bufferingOldestyADyx__GSicAFmlFWC
 _$sScS12ContinuationV15BufferingPolicyO9unboundedyADyx__GAFmlFWC
 _$sScS12ContinuationV15BufferingPolicyOMa
 _$sScS12ContinuationV15BufferingPolicyOMn
+_$sScS12ContinuationV2eeoiySbAByx_G_ADtFZ
+_$sScS12ContinuationV4hash4intoys6HasherVz_tF
 _$sScS12ContinuationV5yield4withAB11YieldResultOyx__Gs0E0Oyxs5NeverOG_tF
 _$sScS12ContinuationV5yieldAB11YieldResultOyyt__GyytRszlF
 _$sScS12ContinuationV5yieldyAB11YieldResultOyx__GxnF
 _$sScS12ContinuationV6finishyyF
+_$sScS12ContinuationV9hashValueSivg
+_$sScS12ContinuationV9hashValueSivpMV
 _$sScS12ContinuationVMa
 _$sScS12ContinuationVMn
+_$sScS12ContinuationVyx_GSHsMc
+_$sScS12ContinuationVyx_GSQsMc
 _$sScS17makeAsyncIteratorScS0C0Vyx_GyF
 _$sScS8IteratorV4nextxSgyYaF
 _$sScS8IteratorV4nextxSgyYaFTu
@@ -213,8 +223,8 @@ _$sScTss5NeverORszABRs_rlE15defaultExecutorSch_pvpZMV
 _$sScTss5NeverORszABRs_rlE17checkCancellationyyKFZ
 _$sScTss5NeverORszABRs_rlE17preferredExecutorSch_pSgvgZ
 _$sScTss5NeverORszABRs_rlE17preferredExecutorSch_pSgvpZMV
-_$sScTss5NeverORszABRs_rlE26currentSchedulableExecutors0cD0_pSgvgZ
-_$sScTss5NeverORszABRs_rlE26currentSchedulableExecutors0cD0_pSgvpZMV
+_$sScTss5NeverORszABRs_rlE25currentSchedulingExecutors0cD0_pSgvgZ
+_$sScTss5NeverORszABRs_rlE25currentSchedulingExecutors0cD0_pSgvpZMV
 _$sScTss5NeverORszABRs_rlE5sleep11nanosecondsys6UInt64V_tYaKFZ
 _$sScTss5NeverORszABRs_rlE5sleep11nanosecondsys6UInt64V_tYaKFZTu
 _$sScTss5NeverORszABRs_rlE5sleep5until9tolerance5clocky7InstantQyd___8DurationQyd__Sgqd__tYaKs5ClockRd__lFZ
@@ -359,12 +369,18 @@ _$sScs12ContinuationV15BufferingPolicyO15bufferingOldestyADyxq___GSicAFms5ErrorR
 _$sScs12ContinuationV15BufferingPolicyO9unboundedyADyxq___GAFms5ErrorR_r0_lFWC
 _$sScs12ContinuationV15BufferingPolicyOMa
 _$sScs12ContinuationV15BufferingPolicyOMn
+_$sScs12ContinuationV2eeoiySbAByxq__G_ADtFZ
+_$sScs12ContinuationV4hash4intoys6HasherVz_tF
 _$sScs12ContinuationV5yield4withAB11YieldResultOyxs5Error_p__Gs0E0OyxsAG_pG_tsAG_pRs_rlF
 _$sScs12ContinuationV5yieldAB11YieldResultOyytq___GyytRszrlF
 _$sScs12ContinuationV5yieldyAB11YieldResultOyxq___GxnF
 _$sScs12ContinuationV6finish8throwingyq_Sgn_tF
+_$sScs12ContinuationV9hashValueSivg
+_$sScs12ContinuationV9hashValueSivpMV
 _$sScs12ContinuationVMa
 _$sScs12ContinuationVMn
+_$sScs12ContinuationVyxq__GSHsMc
+_$sScs12ContinuationVyxq__GSQsMc
 _$sScs17makeAsyncIteratorScs0C0Vyxq__GyF
 _$sScs8IteratorV4nextxSgyYaKF
 _$sScs8IteratorV4nextxSgyYaKFTu
@@ -393,23 +409,6 @@ _$sSctN
 _$sSctSHsMc
 _$sSctSQsMc
 _$ss039_checkIllegalTaskLocalBindingWithinWithC5Group4file4lineySS_SutF
-_$ss11ClockTraitsV10continuousABvgZ
-_$ss11ClockTraitsV10continuousABvpZMV
-_$ss11ClockTraitsV8rawValueABs6UInt32V_tcfC
-_$ss11ClockTraitsV8rawValues6UInt32Vvg
-_$ss11ClockTraitsV8rawValues6UInt32VvpMV
-_$ss11ClockTraitsV8wallTimeABvgZ
-_$ss11ClockTraitsV8wallTimeABvpZMV
-_$ss11ClockTraitsV9monotonicABvgZ
-_$ss11ClockTraitsV9monotonicABvpZMV
-_$ss11ClockTraitsVMa
-_$ss11ClockTraitsVMn
-_$ss11ClockTraitsVN
-_$ss11ClockTraitsVSQsMc
-_$ss11ClockTraitsVSYsMc
-_$ss11ClockTraitsVs10SetAlgebrasMc
-_$ss11ClockTraitsVs25ExpressibleByArrayLiteralsMc
-_$ss11ClockTraitsVs9OptionSetsMc
 _$ss11ExecutorJobV010withUnsafeA11PrivateData4bodyxxSwq_YKXE_tq_YKs5ErrorR_r0_lF
 _$ss11ExecutorJobV11descriptionSSvg
 _$ss11ExecutorJobV14LocalAllocatorV10deallocateyySpyxGlF
@@ -421,6 +420,7 @@ _$ss11ExecutorJobV14LocalAllocatorV8allocate8capacitySwSi_tF
 _$ss11ExecutorJobV14LocalAllocatorVMa
 _$ss11ExecutorJobV14LocalAllocatorVMn
 _$ss11ExecutorJobV14LocalAllocatorVN
+_$ss11ExecutorJobV16createTrampoline2toABx_tScFRzlF
 _$ss11ExecutorJobV4KindV13firstReservedADvgZ
 _$ss11ExecutorJobV4KindV13firstReservedADvpZMV
 _$ss11ExecutorJobV4KindV4taskADvgZ
@@ -459,6 +459,7 @@ _$ss11JobPriorityV2eeoiySbAB_ABtFZ
 _$ss11JobPriorityV2geoiySbAB_ABtFZ
 _$ss11JobPriorityV2leoiySbAB_ABtFZ
 _$ss11JobPriorityV2neoiySbAB_ABtFZ
+_$ss11JobPriorityV8rawValueABs5UInt8V_tcfC
 _$ss11JobPriorityV8rawValues5UInt8VvM
 _$ss11JobPriorityV8rawValues5UInt8Vvg
 _$ss11JobPriorityV8rawValues5UInt8VvpMV
@@ -468,6 +469,7 @@ _$ss11JobPriorityVMn
 _$ss11JobPriorityVN
 _$ss11JobPriorityVSLsMc
 _$ss11JobPriorityVSQsMc
+_$ss11JobPriorityVyABScPcfC
 _$ss12MainExecutorMp
 _$ss12MainExecutorPScfTb
 _$ss12MainExecutorPs07RunLoopB0Tb
@@ -475,35 +477,14 @@ _$ss12MainExecutorTL
 _$ss13_runAsyncMainyyyyYaKcF
 _$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lF
 _$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lFTu
-_$ss14CFMainExecutorC3runyyKF
-_$ss14CFMainExecutorC4stopyyF
-_$ss14CFMainExecutorCABycfC
-_$ss14CFMainExecutorCABycfc
-_$ss14CFMainExecutorCMa
-_$ss14CFMainExecutorCMm
-_$ss14CFMainExecutorCMn
-_$ss14CFMainExecutorCMo
-_$ss14CFMainExecutorCN
-_$ss14CFMainExecutorCfD
-_$ss14CFMainExecutorCfd
-_$ss14CFTaskExecutorCABycfC
-_$ss14CFTaskExecutorCABycfc
-_$ss14CFTaskExecutorCMa
-_$ss14CFTaskExecutorCMm
-_$ss14CFTaskExecutorCMn
-_$ss14CFTaskExecutorCMo
-_$ss14CFTaskExecutorCN
-_$ss14CFTaskExecutorCfD
-_$ss14CFTaskExecutorCfd
 _$ss15ContinuousClockV17minimumResolutions8DurationVvg
 _$ss15ContinuousClockV17minimumResolutions8DurationVvpMV
 _$ss15ContinuousClockV3nowAB7InstantVvg
 _$ss15ContinuousClockV3nowAB7InstantVvgZ
 _$ss15ContinuousClockV3nowAB7InstantVvpMV
+_$ss15ContinuousClockV3run_2at9toleranceys11ExecutorJobVn_AB7InstantVs8DurationVSgtF
 _$ss15ContinuousClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKF
 _$ss15ContinuousClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKFTu
-_$ss15ContinuousClockV6traitss0B6TraitsVvg
-_$ss15ContinuousClockV6traitss0B6TraitsVvpMV
 _$ss15ContinuousClockV7InstantV1loiySbAD_ADtFZ
 _$ss15ContinuousClockV7InstantV2eeoiySbAD_ADtFZ
 _$ss15ContinuousClockV7InstantV3nowADvgZ
@@ -523,6 +504,7 @@ _$ss15ContinuousClockV7InstantVSLsMc
 _$ss15ContinuousClockV7InstantVSQsMc
 _$ss15ContinuousClockV7InstantVSesMc
 _$ss15ContinuousClockV7InstantVs0C8ProtocolsMc
+_$ss15ContinuousClockV7enqueue_2on2at9toleranceys11ExecutorJobVn_xAB7InstantVs8DurationVSgtScFRzlF
 _$ss15ContinuousClockVABycfC
 _$ss15ContinuousClockVMa
 _$ss15ContinuousClockVMn
@@ -550,10 +532,9 @@ _$ss15SuspendingClockV17minimumResolutions8DurationVvpMV
 _$ss15SuspendingClockV3nowAB7InstantVvg
 _$ss15SuspendingClockV3nowAB7InstantVvgZ
 _$ss15SuspendingClockV3nowAB7InstantVvpMV
+_$ss15SuspendingClockV3run_2at9toleranceys11ExecutorJobVn_AB7InstantVs8DurationVSgtF
 _$ss15SuspendingClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKF
 _$ss15SuspendingClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKFTu
-_$ss15SuspendingClockV6traitss0B6TraitsVvg
-_$ss15SuspendingClockV6traitss0B6TraitsVvpMV
 _$ss15SuspendingClockV7InstantV1loiySbAD_ADtFZ
 _$ss15SuspendingClockV7InstantV1poiyA2D_s8DurationVtFZ
 _$ss15SuspendingClockV7InstantV1soiyA2D_s8DurationVtFZ
@@ -578,6 +559,7 @@ _$ss15SuspendingClockV7InstantVSLsMc
 _$ss15SuspendingClockV7InstantVSQsMc
 _$ss15SuspendingClockV7InstantVSesMc
 _$ss15SuspendingClockV7InstantVs0C8ProtocolsMc
+_$ss15SuspendingClockV7enqueue_2on2at9toleranceys11ExecutorJobVn_xAB7InstantVs8DurationVSgtScFRzlF
 _$ss15SuspendingClockVABycfC
 _$ss15SuspendingClockVMa
 _$ss15SuspendingClockVMn
@@ -605,51 +587,15 @@ _$ss16AsyncMapSequenceVMa
 _$ss16AsyncMapSequenceVMn
 _$ss16AsyncMapSequenceV_9transformAByxq_Gx_q_7ElementQzYactcfC
 _$ss16AsyncMapSequenceVyxq_GScisMc
-_$ss17DummyMainExecutorC02isbC0Sbvg
-_$ss17DummyMainExecutorC02isbC0SbvpMV
-_$ss17DummyMainExecutorC13checkIsolatedyyF
-_$ss17DummyMainExecutorC3runyyKF
-_$ss17DummyMainExecutorC4stopyyF
-_$ss17DummyMainExecutorC7enqueueyys0C3JobVnF
-_$ss17DummyMainExecutorCABycfC
-_$ss17DummyMainExecutorCABycfCTj
-_$ss17DummyMainExecutorCABycfCTq
-_$ss17DummyMainExecutorCABycfc
-_$ss17DummyMainExecutorCMa
-_$ss17DummyMainExecutorCMm
-_$ss17DummyMainExecutorCMn
-_$ss17DummyMainExecutorCMo
-_$ss17DummyMainExecutorCMu
-_$ss17DummyMainExecutorCN
-_$ss17DummyMainExecutorCScFsMc
-_$ss17DummyMainExecutorCScFsWP
-_$ss17DummyMainExecutorCScfsMc
-_$ss17DummyMainExecutorCScfsWP
-_$ss17DummyMainExecutorCfD
-_$ss17DummyMainExecutorCfd
-_$ss17DummyMainExecutorCs07RunLoopC0sMc
-_$ss17DummyMainExecutorCs07RunLoopC0sWP
-_$ss17DummyMainExecutorCs0bC0sMc
-_$ss17DummyMainExecutorCs0bC0sWP
-_$ss17DummyTaskExecutorC06isMainC0Sbvg
-_$ss17DummyTaskExecutorC06isMainC0SbvpMV
-_$ss17DummyTaskExecutorC7enqueueyys0C3JobVnF
-_$ss17DummyTaskExecutorCABycfC
-_$ss17DummyTaskExecutorCABycfCTj
-_$ss17DummyTaskExecutorCABycfCTq
-_$ss17DummyTaskExecutorCABycfc
-_$ss17DummyTaskExecutorCMa
-_$ss17DummyTaskExecutorCMm
-_$ss17DummyTaskExecutorCMn
-_$ss17DummyTaskExecutorCMo
-_$ss17DummyTaskExecutorCMu
-_$ss17DummyTaskExecutorCN
-_$ss17DummyTaskExecutorCScFsMc
-_$ss17DummyTaskExecutorCScFsWP
-_$ss17DummyTaskExecutorCSchsMc
-_$ss17DummyTaskExecutorCSchsWP
-_$ss17DummyTaskExecutorCfD
-_$ss17DummyTaskExecutorCfd
+_$ss18SchedulingExecutorMp
+_$ss18SchedulingExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTj
+_$ss18SchedulingExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTq
+_$ss18SchedulingExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTj
+_$ss18SchedulingExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTq
+_$ss18SchedulingExecutorPScFTb
+_$ss18SchedulingExecutorPsE7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lF
+_$ss18SchedulingExecutorPsE7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lF
+_$ss18SchedulingExecutorTL
 _$ss19AsyncFilterSequenceV04makeA8IteratorAB0E0Vyx_GyF
 _$ss19AsyncFilterSequenceV10isIncludedySb7ElementQzYacvg
 _$ss19AsyncFilterSequenceV10isIncludedySb7ElementQzYacvpMV
@@ -707,15 +653,6 @@ _$ss19DiscardingTaskGroupV9cancelAllyyF
 _$ss19DiscardingTaskGroupVMa
 _$ss19DiscardingTaskGroupVMn
 _$ss19DiscardingTaskGroupVN
-_$ss19SchedulableExecutorMp
-_$ss19SchedulableExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTj
-_$ss19SchedulableExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTq
-_$ss19SchedulableExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTj
-_$ss19SchedulableExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTq
-_$ss19SchedulableExecutorPScFTb
-_$ss19SchedulableExecutorPsE7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lF
-_$ss19SchedulableExecutorPsE7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lF
-_$ss19SchedulableExecutorTL
 _$ss19UnownedTaskExecutorV02asbC0Sch_pSgyF
 _$ss19UnownedTaskExecutorVyABxhcSchRzlufC
 _$ss20AsyncFlatMapSequenceV04makeA8IteratorAB0F0Vyxq__GyF
@@ -747,39 +684,6 @@ _$ss20AsyncFlatMapSequenceVMa
 _$ss20AsyncFlatMapSequenceVMn
 _$ss20AsyncFlatMapSequenceV_9transformAByxq_Gx_q_7ElementQzYactcfC
 _$ss20AsyncFlatMapSequenceVyxq_GScisMc
-_$ss20DispatchMainExecutorC02isbC0Sbvg
-_$ss20DispatchMainExecutorC02isbC0SbvpMV
-_$ss20DispatchMainExecutorC13asSchedulables0eC0_pSgvg
-_$ss20DispatchMainExecutorC13asSchedulables0eC0_pSgvpMV
-_$ss20DispatchMainExecutorC13checkIsolatedyyF
-_$ss20DispatchMainExecutorC3runyyKFTj
-_$ss20DispatchMainExecutorC3runyyKFTq
-_$ss20DispatchMainExecutorC4stopyyFTj
-_$ss20DispatchMainExecutorC4stopyyFTq
-_$ss20DispatchMainExecutorC7enqueue_2at9tolerance5clockys0C3JobVn_7InstantQz8DurationQzSgxts5ClockRzlF
-_$ss20DispatchMainExecutorC7enqueueyys0C3JobVnF
-_$ss20DispatchMainExecutorCABycfC
-_$ss20DispatchMainExecutorCABycfCTj
-_$ss20DispatchMainExecutorCABycfCTq
-_$ss20DispatchMainExecutorCABycfc
-_$ss20DispatchMainExecutorCMa
-_$ss20DispatchMainExecutorCMm
-_$ss20DispatchMainExecutorCMn
-_$ss20DispatchMainExecutorCMo
-_$ss20DispatchMainExecutorCMu
-_$ss20DispatchMainExecutorCN
-_$ss20DispatchMainExecutorCScFsMc
-_$ss20DispatchMainExecutorCScFsWP
-_$ss20DispatchMainExecutorCScfsMc
-_$ss20DispatchMainExecutorCScfsWP
-_$ss20DispatchMainExecutorCfD
-_$ss20DispatchMainExecutorCfd
-_$ss20DispatchMainExecutorCs011SchedulableC0sMc
-_$ss20DispatchMainExecutorCs011SchedulableC0sWP
-_$ss20DispatchMainExecutorCs07RunLoopC0sMc
-_$ss20DispatchMainExecutorCs07RunLoopC0sWP
-_$ss20DispatchMainExecutorCs0bC0sMc
-_$ss20DispatchMainExecutorCs0bC0sWP
 _$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lF
 _$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lFTu
 _$ss21withUnsafeCurrentTask4bodyxxSctSgKXE_tKlF
@@ -915,31 +819,51 @@ _$ss24AsyncThrowingMapSequenceVMa
 _$ss24AsyncThrowingMapSequenceVMn
 _$ss24AsyncThrowingMapSequenceV_9transformAByxq_Gx_q_7ElementQzYaKctcfC
 _$ss24AsyncThrowingMapSequenceVyxq_GScisMc
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvgTj
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvgTq
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvpMV
-_$ss26DispatchGlobalTaskExecutorC7enqueue_2at9tolerance5clockys0D3JobVn_7InstantQz8DurationQzSgxts5ClockRzlFTj
-_$ss26DispatchGlobalTaskExecutorC7enqueue_2at9tolerance5clockys0D3JobVn_7InstantQz8DurationQzSgxts5ClockRzlFTq
-_$ss26DispatchGlobalTaskExecutorC7enqueueyys0D3JobVnFTj
-_$ss26DispatchGlobalTaskExecutorC7enqueueyys0D3JobVnFTq
-_$ss26DispatchGlobalTaskExecutorCABycfC
-_$ss26DispatchGlobalTaskExecutorCABycfCTj
-_$ss26DispatchGlobalTaskExecutorCABycfCTq
-_$ss26DispatchGlobalTaskExecutorCABycfc
-_$ss26DispatchGlobalTaskExecutorCMa
-_$ss26DispatchGlobalTaskExecutorCMm
-_$ss26DispatchGlobalTaskExecutorCMn
-_$ss26DispatchGlobalTaskExecutorCMo
-_$ss26DispatchGlobalTaskExecutorCMu
-_$ss26DispatchGlobalTaskExecutorCN
-_$ss26DispatchGlobalTaskExecutorCScFsMc
-_$ss26DispatchGlobalTaskExecutorCScFsWP
-_$ss26DispatchGlobalTaskExecutorCSchsMc
-_$ss26DispatchGlobalTaskExecutorCSchsWP
-_$ss26DispatchGlobalTaskExecutorCfD
-_$ss26DispatchGlobalTaskExecutorCfd
-_$ss26DispatchGlobalTaskExecutorCs011SchedulableD0sMc
-_$ss26DispatchGlobalTaskExecutorCs011SchedulableD0sWP
+_$ss25UnimplementedMainExecutorC02isbC0Sbvg
+_$ss25UnimplementedMainExecutorC02isbC0SbvpMV
+_$ss25UnimplementedMainExecutorC13checkIsolatedyyF
+_$ss25UnimplementedMainExecutorC3runyyKF
+_$ss25UnimplementedMainExecutorC4stopyyF
+_$ss25UnimplementedMainExecutorC7enqueueyys0C3JobVnF
+_$ss25UnimplementedMainExecutorCABycfC
+_$ss25UnimplementedMainExecutorCABycfCTj
+_$ss25UnimplementedMainExecutorCABycfCTq
+_$ss25UnimplementedMainExecutorCABycfc
+_$ss25UnimplementedMainExecutorCMa
+_$ss25UnimplementedMainExecutorCMm
+_$ss25UnimplementedMainExecutorCMn
+_$ss25UnimplementedMainExecutorCMo
+_$ss25UnimplementedMainExecutorCMu
+_$ss25UnimplementedMainExecutorCN
+_$ss25UnimplementedMainExecutorCScFsMc
+_$ss25UnimplementedMainExecutorCScFsWP
+_$ss25UnimplementedMainExecutorCScfsMc
+_$ss25UnimplementedMainExecutorCScfsWP
+_$ss25UnimplementedMainExecutorCfD
+_$ss25UnimplementedMainExecutorCfd
+_$ss25UnimplementedMainExecutorCs07RunLoopC0sMc
+_$ss25UnimplementedMainExecutorCs07RunLoopC0sWP
+_$ss25UnimplementedMainExecutorCs0bC0sMc
+_$ss25UnimplementedMainExecutorCs0bC0sWP
+_$ss25UnimplementedTaskExecutorC06isMainC0Sbvg
+_$ss25UnimplementedTaskExecutorC06isMainC0SbvpMV
+_$ss25UnimplementedTaskExecutorC7enqueueyys0C3JobVnF
+_$ss25UnimplementedTaskExecutorCABycfC
+_$ss25UnimplementedTaskExecutorCABycfCTj
+_$ss25UnimplementedTaskExecutorCABycfCTq
+_$ss25UnimplementedTaskExecutorCABycfc
+_$ss25UnimplementedTaskExecutorCMa
+_$ss25UnimplementedTaskExecutorCMm
+_$ss25UnimplementedTaskExecutorCMn
+_$ss25UnimplementedTaskExecutorCMo
+_$ss25UnimplementedTaskExecutorCMu
+_$ss25UnimplementedTaskExecutorCN
+_$ss25UnimplementedTaskExecutorCScFsMc
+_$ss25UnimplementedTaskExecutorCScFsWP
+_$ss25UnimplementedTaskExecutorCSchsMc
+_$ss25UnimplementedTaskExecutorCSchsWP
+_$ss25UnimplementedTaskExecutorCfD
+_$ss25UnimplementedTaskExecutorCfd
 _$ss27AsyncThrowingFilterSequenceV04makeA8IteratorAB0F0Vyx_GyF
 _$ss27AsyncThrowingFilterSequenceV10isIncludedySb7ElementQzYaKcvg
 _$ss27AsyncThrowingFilterSequenceV10isIncludedySb7ElementQzYaKcvpMV
@@ -1104,29 +1028,21 @@ _$ss5ClockP17minimumResolution8DurationQzvgTj
 _$ss5ClockP17minimumResolution8DurationQzvgTq
 _$ss5ClockP3now7InstantQzvgTj
 _$ss5ClockP3now7InstantQzvgTq
+_$ss5ClockP3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtFTj
+_$ss5ClockP3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtFTq
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTj
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTjTu
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTq
-_$ss5ClockP6traitss0A6TraitsVvgTj
-_$ss5ClockP6traitss0A6TraitsVvgTq
 _$ss5ClockP7InstantAB_s0B8ProtocolTn
-_$ss5ClockP7convert4from8DurationQzSgsAEV_tFTj
-_$ss5ClockP7convert4from8DurationQzSgsAEV_tFTq
-_$ss5ClockP7convert4froms8DurationVSgAEQz_tFTj
-_$ss5ClockP7convert4froms8DurationVSgAEQz_tFTq
-_$ss5ClockP7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lFTj
-_$ss5ClockP7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lFTq
-_$ss5ClockPsE6traitss0A6TraitsVvg
-_$ss5ClockPsE6traitss0A6TraitsVvpMV
-_$ss5ClockPsE7convert4from8DurationQzSgsAEV_tF
-_$ss5ClockPsE7convert4froms8DurationVSgAEQz_tF
-_$ss5ClockPsE7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lF
+_$ss5ClockP7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lFTj
+_$ss5ClockP7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lFTq
+_$ss5ClockPsE3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtF
+_$ss5ClockPsE7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lF
 _$ss5ClockPsE7measurey8DurationQzyyKXEKF
 _$ss5ClockPsE7measurey8DurationQzyyYaKXEYaKF
 _$ss5ClockPsE7measurey8DurationQzyyYaKXEYaKFTu
 _$ss5ClockPss010ContinuousA0VRszrlE10continuousADvgZ
 _$ss5ClockPss010SuspendingA0VRszrlE10suspendingADvgZ
-_$ss5ClockPss8DurationVACRtzrlE7convert4fromADSgAD_tF
 _$ss5ClockTL
 _$ss6_first_5where7ElementQzSgx_SbADYaKXEtYaKSciRzlF
 _$ss6_first_5where7ElementQzSgx_SbADYaKXEtYaKSciRzlFTu
@@ -1160,6 +1076,7 @@ _$ss9TaskLocalCyxGs23CustomStringConvertiblesMc
 _$ss9_contains_5whereSbx_Sb7ElementQzYaKXEtYaKSciRzlF
 _$ss9_contains_5whereSbx_Sb7ElementQzYaKXEtYaKSciRzlFTu
 __swift_concurrency_debug_asyncTaskMetadata
+__swift_concurrency_debug_asyncTaskSize
 __swift_concurrency_debug_asyncTaskSlabMetadata
 __swift_concurrency_debug_future_adapter
 __swift_concurrency_debug_jobMetadata
@@ -1167,6 +1084,7 @@ __swift_concurrency_debug_non_future_adapter
 __swift_concurrency_debug_supportsPriorityEscalation
 __swift_concurrency_debug_task_future_wait_resume_adapter
 __swift_concurrency_debug_task_wait_throwing_resume_adapter
+__swift_createJobForTestingOnly
 _swift_asyncLet_begin
 _swift_asyncLet_consume
 _swift_asyncLet_consume_throwing
diff --git a/test/abi/Inputs/macOS/x86_64/concurrency/baseline b/test/abi/Inputs/macOS/x86_64/concurrency/baseline
index 557c626a2cada..9f91995fd1839 100644
--- a/test/abi/Inputs/macOS/x86_64/concurrency/baseline
+++ b/test/abi/Inputs/macOS/x86_64/concurrency/baseline
@@ -25,6 +25,8 @@ _$sScEN
 _$sScEs5ErrorsMc
 _$sScF14isMainExecutorSbvgTj
 _$sScF14isMainExecutorSbvgTq
+_$sScF20asSchedulingExecutors0bC0_pSgvgTj
+_$sScF20asSchedulingExecutors0bC0_pSgvgTq
 _$sScF7enqueueyyScJFTj
 _$sScF7enqueueyyScJFTq
 _$sScF7enqueueyys11ExecutorJobVnFTj
@@ -37,6 +39,8 @@ _$sScFsE14isMainExecutorSbvg
 _$sScFsE14isMainExecutorSbvpMV
 _$sScFsE18_isComplexEqualitySbvg
 _$sScFsE18_isComplexEqualitySbvpMV
+_$sScFsE20asSchedulingExecutors0bC0_pSgvg
+_$sScFsE20asSchedulingExecutors0bC0_pSgvpMV
 _$sScFsE7enqueueyyScJF
 _$sScFsE7enqueueyys11ExecutorJobVnF
 _$sScFsE7enqueueyys3JobVnF
@@ -164,12 +168,18 @@ _$sScS12ContinuationV15BufferingPolicyO15bufferingOldestyADyx__GSicAFmlFWC
 _$sScS12ContinuationV15BufferingPolicyO9unboundedyADyx__GAFmlFWC
 _$sScS12ContinuationV15BufferingPolicyOMa
 _$sScS12ContinuationV15BufferingPolicyOMn
+_$sScS12ContinuationV2eeoiySbAByx_G_ADtFZ
+_$sScS12ContinuationV4hash4intoys6HasherVz_tF
 _$sScS12ContinuationV5yield4withAB11YieldResultOyx__Gs0E0Oyxs5NeverOG_tF
 _$sScS12ContinuationV5yieldAB11YieldResultOyyt__GyytRszlF
 _$sScS12ContinuationV5yieldyAB11YieldResultOyx__GxnF
 _$sScS12ContinuationV6finishyyF
+_$sScS12ContinuationV9hashValueSivg
+_$sScS12ContinuationV9hashValueSivpMV
 _$sScS12ContinuationVMa
 _$sScS12ContinuationVMn
+_$sScS12ContinuationVyx_GSHsMc
+_$sScS12ContinuationVyx_GSQsMc
 _$sScS17makeAsyncIteratorScS0C0Vyx_GyF
 _$sScS8IteratorV4nextxSgyYaF
 _$sScS8IteratorV4nextxSgyYaFTu
@@ -213,8 +223,8 @@ _$sScTss5NeverORszABRs_rlE15defaultExecutorSch_pvpZMV
 _$sScTss5NeverORszABRs_rlE17checkCancellationyyKFZ
 _$sScTss5NeverORszABRs_rlE17preferredExecutorSch_pSgvgZ
 _$sScTss5NeverORszABRs_rlE17preferredExecutorSch_pSgvpZMV
-_$sScTss5NeverORszABRs_rlE26currentSchedulableExecutors0cD0_pSgvgZ
-_$sScTss5NeverORszABRs_rlE26currentSchedulableExecutors0cD0_pSgvpZMV
+_$sScTss5NeverORszABRs_rlE25currentSchedulingExecutors0cD0_pSgvgZ
+_$sScTss5NeverORszABRs_rlE25currentSchedulingExecutors0cD0_pSgvpZMV
 _$sScTss5NeverORszABRs_rlE5sleep11nanosecondsys6UInt64V_tYaKFZ
 _$sScTss5NeverORszABRs_rlE5sleep11nanosecondsys6UInt64V_tYaKFZTu
 _$sScTss5NeverORszABRs_rlE5sleep5until9tolerance5clocky7InstantQyd___8DurationQyd__Sgqd__tYaKs5ClockRd__lFZ
@@ -359,12 +369,18 @@ _$sScs12ContinuationV15BufferingPolicyO15bufferingOldestyADyxq___GSicAFms5ErrorR
 _$sScs12ContinuationV15BufferingPolicyO9unboundedyADyxq___GAFms5ErrorR_r0_lFWC
 _$sScs12ContinuationV15BufferingPolicyOMa
 _$sScs12ContinuationV15BufferingPolicyOMn
+_$sScs12ContinuationV2eeoiySbAByxq__G_ADtFZ
+_$sScs12ContinuationV4hash4intoys6HasherVz_tF
 _$sScs12ContinuationV5yield4withAB11YieldResultOyxs5Error_p__Gs0E0OyxsAG_pG_tsAG_pRs_rlF
 _$sScs12ContinuationV5yieldAB11YieldResultOyytq___GyytRszrlF
 _$sScs12ContinuationV5yieldyAB11YieldResultOyxq___GxnF
 _$sScs12ContinuationV6finish8throwingyq_Sgn_tF
+_$sScs12ContinuationV9hashValueSivg
+_$sScs12ContinuationV9hashValueSivpMV
 _$sScs12ContinuationVMa
 _$sScs12ContinuationVMn
+_$sScs12ContinuationVyxq__GSHsMc
+_$sScs12ContinuationVyxq__GSQsMc
 _$sScs17makeAsyncIteratorScs0C0Vyxq__GyF
 _$sScs8IteratorV4nextxSgyYaKF
 _$sScs8IteratorV4nextxSgyYaKFTu
@@ -393,23 +409,6 @@ _$sSctN
 _$sSctSHsMc
 _$sSctSQsMc
 _$ss039_checkIllegalTaskLocalBindingWithinWithC5Group4file4lineySS_SutF
-_$ss11ClockTraitsV10continuousABvgZ
-_$ss11ClockTraitsV10continuousABvpZMV
-_$ss11ClockTraitsV8rawValueABs6UInt32V_tcfC
-_$ss11ClockTraitsV8rawValues6UInt32Vvg
-_$ss11ClockTraitsV8rawValues6UInt32VvpMV
-_$ss11ClockTraitsV8wallTimeABvgZ
-_$ss11ClockTraitsV8wallTimeABvpZMV
-_$ss11ClockTraitsV9monotonicABvgZ
-_$ss11ClockTraitsV9monotonicABvpZMV
-_$ss11ClockTraitsVMa
-_$ss11ClockTraitsVMn
-_$ss11ClockTraitsVN
-_$ss11ClockTraitsVSQsMc
-_$ss11ClockTraitsVSYsMc
-_$ss11ClockTraitsVs10SetAlgebrasMc
-_$ss11ClockTraitsVs25ExpressibleByArrayLiteralsMc
-_$ss11ClockTraitsVs9OptionSetsMc
 _$ss11ExecutorJobV010withUnsafeA11PrivateData4bodyxxSwq_YKXE_tq_YKs5ErrorR_r0_lF
 _$ss11ExecutorJobV11descriptionSSvg
 _$ss11ExecutorJobV14LocalAllocatorV10deallocateyySpyxGlF
@@ -421,6 +420,7 @@ _$ss11ExecutorJobV14LocalAllocatorV8allocate8capacitySwSi_tF
 _$ss11ExecutorJobV14LocalAllocatorVMa
 _$ss11ExecutorJobV14LocalAllocatorVMn
 _$ss11ExecutorJobV14LocalAllocatorVN
+_$ss11ExecutorJobV16createTrampoline2toABx_tScFRzlF
 _$ss11ExecutorJobV4KindV13firstReservedADvgZ
 _$ss11ExecutorJobV4KindV13firstReservedADvpZMV
 _$ss11ExecutorJobV4KindV4taskADvgZ
@@ -459,6 +459,7 @@ _$ss11JobPriorityV2eeoiySbAB_ABtFZ
 _$ss11JobPriorityV2geoiySbAB_ABtFZ
 _$ss11JobPriorityV2leoiySbAB_ABtFZ
 _$ss11JobPriorityV2neoiySbAB_ABtFZ
+_$ss11JobPriorityV8rawValueABs5UInt8V_tcfC
 _$ss11JobPriorityV8rawValues5UInt8VvM
 _$ss11JobPriorityV8rawValues5UInt8Vvg
 _$ss11JobPriorityV8rawValues5UInt8VvpMV
@@ -468,6 +469,7 @@ _$ss11JobPriorityVMn
 _$ss11JobPriorityVN
 _$ss11JobPriorityVSLsMc
 _$ss11JobPriorityVSQsMc
+_$ss11JobPriorityVyABScPcfC
 _$ss12MainExecutorMp
 _$ss12MainExecutorPScfTb
 _$ss12MainExecutorPs07RunLoopB0Tb
@@ -475,35 +477,14 @@ _$ss12MainExecutorTL
 _$ss13_runAsyncMainyyyyYaKcF
 _$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lF
 _$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lFTu
-_$ss14CFMainExecutorC3runyyKF
-_$ss14CFMainExecutorC4stopyyF
-_$ss14CFMainExecutorCABycfC
-_$ss14CFMainExecutorCABycfc
-_$ss14CFMainExecutorCMa
-_$ss14CFMainExecutorCMm
-_$ss14CFMainExecutorCMn
-_$ss14CFMainExecutorCMo
-_$ss14CFMainExecutorCN
-_$ss14CFMainExecutorCfD
-_$ss14CFMainExecutorCfd
-_$ss14CFTaskExecutorCABycfC
-_$ss14CFTaskExecutorCABycfc
-_$ss14CFTaskExecutorCMa
-_$ss14CFTaskExecutorCMm
-_$ss14CFTaskExecutorCMn
-_$ss14CFTaskExecutorCMo
-_$ss14CFTaskExecutorCN
-_$ss14CFTaskExecutorCfD
-_$ss14CFTaskExecutorCfd
 _$ss15ContinuousClockV17minimumResolutions8DurationVvg
 _$ss15ContinuousClockV17minimumResolutions8DurationVvpMV
 _$ss15ContinuousClockV3nowAB7InstantVvg
 _$ss15ContinuousClockV3nowAB7InstantVvgZ
 _$ss15ContinuousClockV3nowAB7InstantVvpMV
+_$ss15ContinuousClockV3run_2at9toleranceys11ExecutorJobVn_AB7InstantVs8DurationVSgtF
 _$ss15ContinuousClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKF
 _$ss15ContinuousClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKFTu
-_$ss15ContinuousClockV6traitss0B6TraitsVvg
-_$ss15ContinuousClockV6traitss0B6TraitsVvpMV
 _$ss15ContinuousClockV7InstantV1loiySbAD_ADtFZ
 _$ss15ContinuousClockV7InstantV2eeoiySbAD_ADtFZ
 _$ss15ContinuousClockV7InstantV3nowADvgZ
@@ -523,6 +504,7 @@ _$ss15ContinuousClockV7InstantVSLsMc
 _$ss15ContinuousClockV7InstantVSQsMc
 _$ss15ContinuousClockV7InstantVSesMc
 _$ss15ContinuousClockV7InstantVs0C8ProtocolsMc
+_$ss15ContinuousClockV7enqueue_2on2at9toleranceys11ExecutorJobVn_xAB7InstantVs8DurationVSgtScFRzlF
 _$ss15ContinuousClockVABycfC
 _$ss15ContinuousClockVMa
 _$ss15ContinuousClockVMn
@@ -550,10 +532,9 @@ _$ss15SuspendingClockV17minimumResolutions8DurationVvpMV
 _$ss15SuspendingClockV3nowAB7InstantVvg
 _$ss15SuspendingClockV3nowAB7InstantVvgZ
 _$ss15SuspendingClockV3nowAB7InstantVvpMV
+_$ss15SuspendingClockV3run_2at9toleranceys11ExecutorJobVn_AB7InstantVs8DurationVSgtF
 _$ss15SuspendingClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKF
 _$ss15SuspendingClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKFTu
-_$ss15SuspendingClockV6traitss0B6TraitsVvg
-_$ss15SuspendingClockV6traitss0B6TraitsVvpMV
 _$ss15SuspendingClockV7InstantV1loiySbAD_ADtFZ
 _$ss15SuspendingClockV7InstantV1poiyA2D_s8DurationVtFZ
 _$ss15SuspendingClockV7InstantV1soiyA2D_s8DurationVtFZ
@@ -578,6 +559,7 @@ _$ss15SuspendingClockV7InstantVSLsMc
 _$ss15SuspendingClockV7InstantVSQsMc
 _$ss15SuspendingClockV7InstantVSesMc
 _$ss15SuspendingClockV7InstantVs0C8ProtocolsMc
+_$ss15SuspendingClockV7enqueue_2on2at9toleranceys11ExecutorJobVn_xAB7InstantVs8DurationVSgtScFRzlF
 _$ss15SuspendingClockVABycfC
 _$ss15SuspendingClockVMa
 _$ss15SuspendingClockVMn
@@ -605,51 +587,15 @@ _$ss16AsyncMapSequenceVMa
 _$ss16AsyncMapSequenceVMn
 _$ss16AsyncMapSequenceV_9transformAByxq_Gx_q_7ElementQzYactcfC
 _$ss16AsyncMapSequenceVyxq_GScisMc
-_$ss17DummyMainExecutorC02isbC0Sbvg
-_$ss17DummyMainExecutorC02isbC0SbvpMV
-_$ss17DummyMainExecutorC13checkIsolatedyyF
-_$ss17DummyMainExecutorC3runyyKF
-_$ss17DummyMainExecutorC4stopyyF
-_$ss17DummyMainExecutorC7enqueueyys0C3JobVnF
-_$ss17DummyMainExecutorCABycfC
-_$ss17DummyMainExecutorCABycfCTj
-_$ss17DummyMainExecutorCABycfCTq
-_$ss17DummyMainExecutorCABycfc
-_$ss17DummyMainExecutorCMa
-_$ss17DummyMainExecutorCMm
-_$ss17DummyMainExecutorCMn
-_$ss17DummyMainExecutorCMo
-_$ss17DummyMainExecutorCMu
-_$ss17DummyMainExecutorCN
-_$ss17DummyMainExecutorCScFsMc
-_$ss17DummyMainExecutorCScFsWP
-_$ss17DummyMainExecutorCScfsMc
-_$ss17DummyMainExecutorCScfsWP
-_$ss17DummyMainExecutorCfD
-_$ss17DummyMainExecutorCfd
-_$ss17DummyMainExecutorCs07RunLoopC0sMc
-_$ss17DummyMainExecutorCs07RunLoopC0sWP
-_$ss17DummyMainExecutorCs0bC0sMc
-_$ss17DummyMainExecutorCs0bC0sWP
-_$ss17DummyTaskExecutorC06isMainC0Sbvg
-_$ss17DummyTaskExecutorC06isMainC0SbvpMV
-_$ss17DummyTaskExecutorC7enqueueyys0C3JobVnF
-_$ss17DummyTaskExecutorCABycfC
-_$ss17DummyTaskExecutorCABycfCTj
-_$ss17DummyTaskExecutorCABycfCTq
-_$ss17DummyTaskExecutorCABycfc
-_$ss17DummyTaskExecutorCMa
-_$ss17DummyTaskExecutorCMm
-_$ss17DummyTaskExecutorCMn
-_$ss17DummyTaskExecutorCMo
-_$ss17DummyTaskExecutorCMu
-_$ss17DummyTaskExecutorCN
-_$ss17DummyTaskExecutorCScFsMc
-_$ss17DummyTaskExecutorCScFsWP
-_$ss17DummyTaskExecutorCSchsMc
-_$ss17DummyTaskExecutorCSchsWP
-_$ss17DummyTaskExecutorCfD
-_$ss17DummyTaskExecutorCfd
+_$ss18SchedulingExecutorMp
+_$ss18SchedulingExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTj
+_$ss18SchedulingExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTq
+_$ss18SchedulingExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTj
+_$ss18SchedulingExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTq
+_$ss18SchedulingExecutorPScFTb
+_$ss18SchedulingExecutorPsE7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lF
+_$ss18SchedulingExecutorPsE7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lF
+_$ss18SchedulingExecutorTL
 _$ss19AsyncFilterSequenceV04makeA8IteratorAB0E0Vyx_GyF
 _$ss19AsyncFilterSequenceV10isIncludedySb7ElementQzYacvg
 _$ss19AsyncFilterSequenceV10isIncludedySb7ElementQzYacvpMV
@@ -707,15 +653,6 @@ _$ss19DiscardingTaskGroupV9cancelAllyyF
 _$ss19DiscardingTaskGroupVMa
 _$ss19DiscardingTaskGroupVMn
 _$ss19DiscardingTaskGroupVN
-_$ss19SchedulableExecutorMp
-_$ss19SchedulableExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTj
-_$ss19SchedulableExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTq
-_$ss19SchedulableExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTj
-_$ss19SchedulableExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTq
-_$ss19SchedulableExecutorPScFTb
-_$ss19SchedulableExecutorPsE7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lF
-_$ss19SchedulableExecutorPsE7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lF
-_$ss19SchedulableExecutorTL
 _$ss19UnownedTaskExecutorV02asbC0Sch_pSgyF
 _$ss19UnownedTaskExecutorVyABxhcSchRzlufC
 _$ss20AsyncFlatMapSequenceV04makeA8IteratorAB0F0Vyxq__GyF
@@ -747,39 +684,6 @@ _$ss20AsyncFlatMapSequenceVMa
 _$ss20AsyncFlatMapSequenceVMn
 _$ss20AsyncFlatMapSequenceV_9transformAByxq_Gx_q_7ElementQzYactcfC
 _$ss20AsyncFlatMapSequenceVyxq_GScisMc
-_$ss20DispatchMainExecutorC02isbC0Sbvg
-_$ss20DispatchMainExecutorC02isbC0SbvpMV
-_$ss20DispatchMainExecutorC13asSchedulables0eC0_pSgvg
-_$ss20DispatchMainExecutorC13asSchedulables0eC0_pSgvpMV
-_$ss20DispatchMainExecutorC13checkIsolatedyyF
-_$ss20DispatchMainExecutorC3runyyKFTj
-_$ss20DispatchMainExecutorC3runyyKFTq
-_$ss20DispatchMainExecutorC4stopyyFTj
-_$ss20DispatchMainExecutorC4stopyyFTq
-_$ss20DispatchMainExecutorC7enqueue_2at9tolerance5clockys0C3JobVn_7InstantQz8DurationQzSgxts5ClockRzlF
-_$ss20DispatchMainExecutorC7enqueueyys0C3JobVnF
-_$ss20DispatchMainExecutorCABycfC
-_$ss20DispatchMainExecutorCABycfCTj
-_$ss20DispatchMainExecutorCABycfCTq
-_$ss20DispatchMainExecutorCABycfc
-_$ss20DispatchMainExecutorCMa
-_$ss20DispatchMainExecutorCMm
-_$ss20DispatchMainExecutorCMn
-_$ss20DispatchMainExecutorCMo
-_$ss20DispatchMainExecutorCMu
-_$ss20DispatchMainExecutorCN
-_$ss20DispatchMainExecutorCScFsMc
-_$ss20DispatchMainExecutorCScFsWP
-_$ss20DispatchMainExecutorCScfsMc
-_$ss20DispatchMainExecutorCScfsWP
-_$ss20DispatchMainExecutorCfD
-_$ss20DispatchMainExecutorCfd
-_$ss20DispatchMainExecutorCs011SchedulableC0sMc
-_$ss20DispatchMainExecutorCs011SchedulableC0sWP
-_$ss20DispatchMainExecutorCs07RunLoopC0sMc
-_$ss20DispatchMainExecutorCs07RunLoopC0sWP
-_$ss20DispatchMainExecutorCs0bC0sMc
-_$ss20DispatchMainExecutorCs0bC0sWP
 _$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lF
 _$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lFTu
 _$ss21withUnsafeCurrentTask4bodyxxSctSgKXE_tKlF
@@ -915,31 +819,51 @@ _$ss24AsyncThrowingMapSequenceVMa
 _$ss24AsyncThrowingMapSequenceVMn
 _$ss24AsyncThrowingMapSequenceV_9transformAByxq_Gx_q_7ElementQzYaKctcfC
 _$ss24AsyncThrowingMapSequenceVyxq_GScisMc
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvgTj
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvgTq
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvpMV
-_$ss26DispatchGlobalTaskExecutorC7enqueue_2at9tolerance5clockys0D3JobVn_7InstantQz8DurationQzSgxts5ClockRzlFTj
-_$ss26DispatchGlobalTaskExecutorC7enqueue_2at9tolerance5clockys0D3JobVn_7InstantQz8DurationQzSgxts5ClockRzlFTq
-_$ss26DispatchGlobalTaskExecutorC7enqueueyys0D3JobVnFTj
-_$ss26DispatchGlobalTaskExecutorC7enqueueyys0D3JobVnFTq
-_$ss26DispatchGlobalTaskExecutorCABycfC
-_$ss26DispatchGlobalTaskExecutorCABycfCTj
-_$ss26DispatchGlobalTaskExecutorCABycfCTq
-_$ss26DispatchGlobalTaskExecutorCABycfc
-_$ss26DispatchGlobalTaskExecutorCMa
-_$ss26DispatchGlobalTaskExecutorCMm
-_$ss26DispatchGlobalTaskExecutorCMn
-_$ss26DispatchGlobalTaskExecutorCMo
-_$ss26DispatchGlobalTaskExecutorCMu
-_$ss26DispatchGlobalTaskExecutorCN
-_$ss26DispatchGlobalTaskExecutorCScFsMc
-_$ss26DispatchGlobalTaskExecutorCScFsWP
-_$ss26DispatchGlobalTaskExecutorCSchsMc
-_$ss26DispatchGlobalTaskExecutorCSchsWP
-_$ss26DispatchGlobalTaskExecutorCfD
-_$ss26DispatchGlobalTaskExecutorCfd
-_$ss26DispatchGlobalTaskExecutorCs011SchedulableD0sMc
-_$ss26DispatchGlobalTaskExecutorCs011SchedulableD0sWP
+_$ss25UnimplementedMainExecutorC02isbC0Sbvg
+_$ss25UnimplementedMainExecutorC02isbC0SbvpMV
+_$ss25UnimplementedMainExecutorC13checkIsolatedyyF
+_$ss25UnimplementedMainExecutorC3runyyKF
+_$ss25UnimplementedMainExecutorC4stopyyF
+_$ss25UnimplementedMainExecutorC7enqueueyys0C3JobVnF
+_$ss25UnimplementedMainExecutorCABycfC
+_$ss25UnimplementedMainExecutorCABycfCTj
+_$ss25UnimplementedMainExecutorCABycfCTq
+_$ss25UnimplementedMainExecutorCABycfc
+_$ss25UnimplementedMainExecutorCMa
+_$ss25UnimplementedMainExecutorCMm
+_$ss25UnimplementedMainExecutorCMn
+_$ss25UnimplementedMainExecutorCMo
+_$ss25UnimplementedMainExecutorCMu
+_$ss25UnimplementedMainExecutorCN
+_$ss25UnimplementedMainExecutorCScFsMc
+_$ss25UnimplementedMainExecutorCScFsWP
+_$ss25UnimplementedMainExecutorCScfsMc
+_$ss25UnimplementedMainExecutorCScfsWP
+_$ss25UnimplementedMainExecutorCfD
+_$ss25UnimplementedMainExecutorCfd
+_$ss25UnimplementedMainExecutorCs07RunLoopC0sMc
+_$ss25UnimplementedMainExecutorCs07RunLoopC0sWP
+_$ss25UnimplementedMainExecutorCs0bC0sMc
+_$ss25UnimplementedMainExecutorCs0bC0sWP
+_$ss25UnimplementedTaskExecutorC06isMainC0Sbvg
+_$ss25UnimplementedTaskExecutorC06isMainC0SbvpMV
+_$ss25UnimplementedTaskExecutorC7enqueueyys0C3JobVnF
+_$ss25UnimplementedTaskExecutorCABycfC
+_$ss25UnimplementedTaskExecutorCABycfCTj
+_$ss25UnimplementedTaskExecutorCABycfCTq
+_$ss25UnimplementedTaskExecutorCABycfc
+_$ss25UnimplementedTaskExecutorCMa
+_$ss25UnimplementedTaskExecutorCMm
+_$ss25UnimplementedTaskExecutorCMn
+_$ss25UnimplementedTaskExecutorCMo
+_$ss25UnimplementedTaskExecutorCMu
+_$ss25UnimplementedTaskExecutorCN
+_$ss25UnimplementedTaskExecutorCScFsMc
+_$ss25UnimplementedTaskExecutorCScFsWP
+_$ss25UnimplementedTaskExecutorCSchsMc
+_$ss25UnimplementedTaskExecutorCSchsWP
+_$ss25UnimplementedTaskExecutorCfD
+_$ss25UnimplementedTaskExecutorCfd
 _$ss27AsyncThrowingFilterSequenceV04makeA8IteratorAB0F0Vyx_GyF
 _$ss27AsyncThrowingFilterSequenceV10isIncludedySb7ElementQzYaKcvg
 _$ss27AsyncThrowingFilterSequenceV10isIncludedySb7ElementQzYaKcvpMV
@@ -1104,29 +1028,21 @@ _$ss5ClockP17minimumResolution8DurationQzvgTj
 _$ss5ClockP17minimumResolution8DurationQzvgTq
 _$ss5ClockP3now7InstantQzvgTj
 _$ss5ClockP3now7InstantQzvgTq
+_$ss5ClockP3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtFTj
+_$ss5ClockP3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtFTq
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTj
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTjTu
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTq
-_$ss5ClockP6traitss0A6TraitsVvgTj
-_$ss5ClockP6traitss0A6TraitsVvgTq
 _$ss5ClockP7InstantAB_s0B8ProtocolTn
-_$ss5ClockP7convert4from8DurationQzSgsAEV_tFTj
-_$ss5ClockP7convert4from8DurationQzSgsAEV_tFTq
-_$ss5ClockP7convert4froms8DurationVSgAEQz_tFTj
-_$ss5ClockP7convert4froms8DurationVSgAEQz_tFTq
-_$ss5ClockP7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lFTj
-_$ss5ClockP7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lFTq
-_$ss5ClockPsE6traitss0A6TraitsVvg
-_$ss5ClockPsE6traitss0A6TraitsVvpMV
-_$ss5ClockPsE7convert4from8DurationQzSgsAEV_tF
-_$ss5ClockPsE7convert4froms8DurationVSgAEQz_tF
-_$ss5ClockPsE7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lF
+_$ss5ClockP7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lFTj
+_$ss5ClockP7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lFTq
+_$ss5ClockPsE3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtF
+_$ss5ClockPsE7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lF
 _$ss5ClockPsE7measurey8DurationQzyyKXEKF
 _$ss5ClockPsE7measurey8DurationQzyyYaKXEYaKF
 _$ss5ClockPsE7measurey8DurationQzyyYaKXEYaKFTu
 _$ss5ClockPss010ContinuousA0VRszrlE10continuousADvgZ
 _$ss5ClockPss010SuspendingA0VRszrlE10suspendingADvgZ
-_$ss5ClockPss8DurationVACRtzrlE7convert4fromADSgAD_tF
 _$ss5ClockTL
 _$ss6_first_5where7ElementQzSgx_SbADYaKXEtYaKSciRzlF
 _$ss6_first_5where7ElementQzSgx_SbADYaKXEtYaKSciRzlFTu
@@ -1160,6 +1076,7 @@ _$ss9TaskLocalCyxGs23CustomStringConvertiblesMc
 _$ss9_contains_5whereSbx_Sb7ElementQzYaKXEtYaKSciRzlF
 _$ss9_contains_5whereSbx_Sb7ElementQzYaKXEtYaKSciRzlFTu
 __swift_concurrency_debug_asyncTaskMetadata
+__swift_concurrency_debug_asyncTaskSize
 __swift_concurrency_debug_asyncTaskSlabMetadata
 __swift_concurrency_debug_future_adapter
 __swift_concurrency_debug_jobMetadata
@@ -1167,6 +1084,7 @@ __swift_concurrency_debug_non_future_adapter
 __swift_concurrency_debug_supportsPriorityEscalation
 __swift_concurrency_debug_task_future_wait_resume_adapter
 __swift_concurrency_debug_task_wait_throwing_resume_adapter
+__swift_createJobForTestingOnly
 _swift_asyncLet_begin
 _swift_asyncLet_consume
 _swift_asyncLet_consume_throwing
diff --git a/test/abi/Inputs/macOS/x86_64/concurrency/baseline-asserts b/test/abi/Inputs/macOS/x86_64/concurrency/baseline-asserts
index 557c626a2cada..9f91995fd1839 100644
--- a/test/abi/Inputs/macOS/x86_64/concurrency/baseline-asserts
+++ b/test/abi/Inputs/macOS/x86_64/concurrency/baseline-asserts
@@ -25,6 +25,8 @@ _$sScEN
 _$sScEs5ErrorsMc
 _$sScF14isMainExecutorSbvgTj
 _$sScF14isMainExecutorSbvgTq
+_$sScF20asSchedulingExecutors0bC0_pSgvgTj
+_$sScF20asSchedulingExecutors0bC0_pSgvgTq
 _$sScF7enqueueyyScJFTj
 _$sScF7enqueueyyScJFTq
 _$sScF7enqueueyys11ExecutorJobVnFTj
@@ -37,6 +39,8 @@ _$sScFsE14isMainExecutorSbvg
 _$sScFsE14isMainExecutorSbvpMV
 _$sScFsE18_isComplexEqualitySbvg
 _$sScFsE18_isComplexEqualitySbvpMV
+_$sScFsE20asSchedulingExecutors0bC0_pSgvg
+_$sScFsE20asSchedulingExecutors0bC0_pSgvpMV
 _$sScFsE7enqueueyyScJF
 _$sScFsE7enqueueyys11ExecutorJobVnF
 _$sScFsE7enqueueyys3JobVnF
@@ -164,12 +168,18 @@ _$sScS12ContinuationV15BufferingPolicyO15bufferingOldestyADyx__GSicAFmlFWC
 _$sScS12ContinuationV15BufferingPolicyO9unboundedyADyx__GAFmlFWC
 _$sScS12ContinuationV15BufferingPolicyOMa
 _$sScS12ContinuationV15BufferingPolicyOMn
+_$sScS12ContinuationV2eeoiySbAByx_G_ADtFZ
+_$sScS12ContinuationV4hash4intoys6HasherVz_tF
 _$sScS12ContinuationV5yield4withAB11YieldResultOyx__Gs0E0Oyxs5NeverOG_tF
 _$sScS12ContinuationV5yieldAB11YieldResultOyyt__GyytRszlF
 _$sScS12ContinuationV5yieldyAB11YieldResultOyx__GxnF
 _$sScS12ContinuationV6finishyyF
+_$sScS12ContinuationV9hashValueSivg
+_$sScS12ContinuationV9hashValueSivpMV
 _$sScS12ContinuationVMa
 _$sScS12ContinuationVMn
+_$sScS12ContinuationVyx_GSHsMc
+_$sScS12ContinuationVyx_GSQsMc
 _$sScS17makeAsyncIteratorScS0C0Vyx_GyF
 _$sScS8IteratorV4nextxSgyYaF
 _$sScS8IteratorV4nextxSgyYaFTu
@@ -213,8 +223,8 @@ _$sScTss5NeverORszABRs_rlE15defaultExecutorSch_pvpZMV
 _$sScTss5NeverORszABRs_rlE17checkCancellationyyKFZ
 _$sScTss5NeverORszABRs_rlE17preferredExecutorSch_pSgvgZ
 _$sScTss5NeverORszABRs_rlE17preferredExecutorSch_pSgvpZMV
-_$sScTss5NeverORszABRs_rlE26currentSchedulableExecutors0cD0_pSgvgZ
-_$sScTss5NeverORszABRs_rlE26currentSchedulableExecutors0cD0_pSgvpZMV
+_$sScTss5NeverORszABRs_rlE25currentSchedulingExecutors0cD0_pSgvgZ
+_$sScTss5NeverORszABRs_rlE25currentSchedulingExecutors0cD0_pSgvpZMV
 _$sScTss5NeverORszABRs_rlE5sleep11nanosecondsys6UInt64V_tYaKFZ
 _$sScTss5NeverORszABRs_rlE5sleep11nanosecondsys6UInt64V_tYaKFZTu
 _$sScTss5NeverORszABRs_rlE5sleep5until9tolerance5clocky7InstantQyd___8DurationQyd__Sgqd__tYaKs5ClockRd__lFZ
@@ -359,12 +369,18 @@ _$sScs12ContinuationV15BufferingPolicyO15bufferingOldestyADyxq___GSicAFms5ErrorR
 _$sScs12ContinuationV15BufferingPolicyO9unboundedyADyxq___GAFms5ErrorR_r0_lFWC
 _$sScs12ContinuationV15BufferingPolicyOMa
 _$sScs12ContinuationV15BufferingPolicyOMn
+_$sScs12ContinuationV2eeoiySbAByxq__G_ADtFZ
+_$sScs12ContinuationV4hash4intoys6HasherVz_tF
 _$sScs12ContinuationV5yield4withAB11YieldResultOyxs5Error_p__Gs0E0OyxsAG_pG_tsAG_pRs_rlF
 _$sScs12ContinuationV5yieldAB11YieldResultOyytq___GyytRszrlF
 _$sScs12ContinuationV5yieldyAB11YieldResultOyxq___GxnF
 _$sScs12ContinuationV6finish8throwingyq_Sgn_tF
+_$sScs12ContinuationV9hashValueSivg
+_$sScs12ContinuationV9hashValueSivpMV
 _$sScs12ContinuationVMa
 _$sScs12ContinuationVMn
+_$sScs12ContinuationVyxq__GSHsMc
+_$sScs12ContinuationVyxq__GSQsMc
 _$sScs17makeAsyncIteratorScs0C0Vyxq__GyF
 _$sScs8IteratorV4nextxSgyYaKF
 _$sScs8IteratorV4nextxSgyYaKFTu
@@ -393,23 +409,6 @@ _$sSctN
 _$sSctSHsMc
 _$sSctSQsMc
 _$ss039_checkIllegalTaskLocalBindingWithinWithC5Group4file4lineySS_SutF
-_$ss11ClockTraitsV10continuousABvgZ
-_$ss11ClockTraitsV10continuousABvpZMV
-_$ss11ClockTraitsV8rawValueABs6UInt32V_tcfC
-_$ss11ClockTraitsV8rawValues6UInt32Vvg
-_$ss11ClockTraitsV8rawValues6UInt32VvpMV
-_$ss11ClockTraitsV8wallTimeABvgZ
-_$ss11ClockTraitsV8wallTimeABvpZMV
-_$ss11ClockTraitsV9monotonicABvgZ
-_$ss11ClockTraitsV9monotonicABvpZMV
-_$ss11ClockTraitsVMa
-_$ss11ClockTraitsVMn
-_$ss11ClockTraitsVN
-_$ss11ClockTraitsVSQsMc
-_$ss11ClockTraitsVSYsMc
-_$ss11ClockTraitsVs10SetAlgebrasMc
-_$ss11ClockTraitsVs25ExpressibleByArrayLiteralsMc
-_$ss11ClockTraitsVs9OptionSetsMc
 _$ss11ExecutorJobV010withUnsafeA11PrivateData4bodyxxSwq_YKXE_tq_YKs5ErrorR_r0_lF
 _$ss11ExecutorJobV11descriptionSSvg
 _$ss11ExecutorJobV14LocalAllocatorV10deallocateyySpyxGlF
@@ -421,6 +420,7 @@ _$ss11ExecutorJobV14LocalAllocatorV8allocate8capacitySwSi_tF
 _$ss11ExecutorJobV14LocalAllocatorVMa
 _$ss11ExecutorJobV14LocalAllocatorVMn
 _$ss11ExecutorJobV14LocalAllocatorVN
+_$ss11ExecutorJobV16createTrampoline2toABx_tScFRzlF
 _$ss11ExecutorJobV4KindV13firstReservedADvgZ
 _$ss11ExecutorJobV4KindV13firstReservedADvpZMV
 _$ss11ExecutorJobV4KindV4taskADvgZ
@@ -459,6 +459,7 @@ _$ss11JobPriorityV2eeoiySbAB_ABtFZ
 _$ss11JobPriorityV2geoiySbAB_ABtFZ
 _$ss11JobPriorityV2leoiySbAB_ABtFZ
 _$ss11JobPriorityV2neoiySbAB_ABtFZ
+_$ss11JobPriorityV8rawValueABs5UInt8V_tcfC
 _$ss11JobPriorityV8rawValues5UInt8VvM
 _$ss11JobPriorityV8rawValues5UInt8Vvg
 _$ss11JobPriorityV8rawValues5UInt8VvpMV
@@ -468,6 +469,7 @@ _$ss11JobPriorityVMn
 _$ss11JobPriorityVN
 _$ss11JobPriorityVSLsMc
 _$ss11JobPriorityVSQsMc
+_$ss11JobPriorityVyABScPcfC
 _$ss12MainExecutorMp
 _$ss12MainExecutorPScfTb
 _$ss12MainExecutorPs07RunLoopB0Tb
@@ -475,35 +477,14 @@ _$ss12MainExecutorTL
 _$ss13_runAsyncMainyyyyYaKcF
 _$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lF
 _$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lFTu
-_$ss14CFMainExecutorC3runyyKF
-_$ss14CFMainExecutorC4stopyyF
-_$ss14CFMainExecutorCABycfC
-_$ss14CFMainExecutorCABycfc
-_$ss14CFMainExecutorCMa
-_$ss14CFMainExecutorCMm
-_$ss14CFMainExecutorCMn
-_$ss14CFMainExecutorCMo
-_$ss14CFMainExecutorCN
-_$ss14CFMainExecutorCfD
-_$ss14CFMainExecutorCfd
-_$ss14CFTaskExecutorCABycfC
-_$ss14CFTaskExecutorCABycfc
-_$ss14CFTaskExecutorCMa
-_$ss14CFTaskExecutorCMm
-_$ss14CFTaskExecutorCMn
-_$ss14CFTaskExecutorCMo
-_$ss14CFTaskExecutorCN
-_$ss14CFTaskExecutorCfD
-_$ss14CFTaskExecutorCfd
 _$ss15ContinuousClockV17minimumResolutions8DurationVvg
 _$ss15ContinuousClockV17minimumResolutions8DurationVvpMV
 _$ss15ContinuousClockV3nowAB7InstantVvg
 _$ss15ContinuousClockV3nowAB7InstantVvgZ
 _$ss15ContinuousClockV3nowAB7InstantVvpMV
+_$ss15ContinuousClockV3run_2at9toleranceys11ExecutorJobVn_AB7InstantVs8DurationVSgtF
 _$ss15ContinuousClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKF
 _$ss15ContinuousClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKFTu
-_$ss15ContinuousClockV6traitss0B6TraitsVvg
-_$ss15ContinuousClockV6traitss0B6TraitsVvpMV
 _$ss15ContinuousClockV7InstantV1loiySbAD_ADtFZ
 _$ss15ContinuousClockV7InstantV2eeoiySbAD_ADtFZ
 _$ss15ContinuousClockV7InstantV3nowADvgZ
@@ -523,6 +504,7 @@ _$ss15ContinuousClockV7InstantVSLsMc
 _$ss15ContinuousClockV7InstantVSQsMc
 _$ss15ContinuousClockV7InstantVSesMc
 _$ss15ContinuousClockV7InstantVs0C8ProtocolsMc
+_$ss15ContinuousClockV7enqueue_2on2at9toleranceys11ExecutorJobVn_xAB7InstantVs8DurationVSgtScFRzlF
 _$ss15ContinuousClockVABycfC
 _$ss15ContinuousClockVMa
 _$ss15ContinuousClockVMn
@@ -550,10 +532,9 @@ _$ss15SuspendingClockV17minimumResolutions8DurationVvpMV
 _$ss15SuspendingClockV3nowAB7InstantVvg
 _$ss15SuspendingClockV3nowAB7InstantVvgZ
 _$ss15SuspendingClockV3nowAB7InstantVvpMV
+_$ss15SuspendingClockV3run_2at9toleranceys11ExecutorJobVn_AB7InstantVs8DurationVSgtF
 _$ss15SuspendingClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKF
 _$ss15SuspendingClockV5sleep5until9toleranceyAB7InstantV_s8DurationVSgtYaKFTu
-_$ss15SuspendingClockV6traitss0B6TraitsVvg
-_$ss15SuspendingClockV6traitss0B6TraitsVvpMV
 _$ss15SuspendingClockV7InstantV1loiySbAD_ADtFZ
 _$ss15SuspendingClockV7InstantV1poiyA2D_s8DurationVtFZ
 _$ss15SuspendingClockV7InstantV1soiyA2D_s8DurationVtFZ
@@ -578,6 +559,7 @@ _$ss15SuspendingClockV7InstantVSLsMc
 _$ss15SuspendingClockV7InstantVSQsMc
 _$ss15SuspendingClockV7InstantVSesMc
 _$ss15SuspendingClockV7InstantVs0C8ProtocolsMc
+_$ss15SuspendingClockV7enqueue_2on2at9toleranceys11ExecutorJobVn_xAB7InstantVs8DurationVSgtScFRzlF
 _$ss15SuspendingClockVABycfC
 _$ss15SuspendingClockVMa
 _$ss15SuspendingClockVMn
@@ -605,51 +587,15 @@ _$ss16AsyncMapSequenceVMa
 _$ss16AsyncMapSequenceVMn
 _$ss16AsyncMapSequenceV_9transformAByxq_Gx_q_7ElementQzYactcfC
 _$ss16AsyncMapSequenceVyxq_GScisMc
-_$ss17DummyMainExecutorC02isbC0Sbvg
-_$ss17DummyMainExecutorC02isbC0SbvpMV
-_$ss17DummyMainExecutorC13checkIsolatedyyF
-_$ss17DummyMainExecutorC3runyyKF
-_$ss17DummyMainExecutorC4stopyyF
-_$ss17DummyMainExecutorC7enqueueyys0C3JobVnF
-_$ss17DummyMainExecutorCABycfC
-_$ss17DummyMainExecutorCABycfCTj
-_$ss17DummyMainExecutorCABycfCTq
-_$ss17DummyMainExecutorCABycfc
-_$ss17DummyMainExecutorCMa
-_$ss17DummyMainExecutorCMm
-_$ss17DummyMainExecutorCMn
-_$ss17DummyMainExecutorCMo
-_$ss17DummyMainExecutorCMu
-_$ss17DummyMainExecutorCN
-_$ss17DummyMainExecutorCScFsMc
-_$ss17DummyMainExecutorCScFsWP
-_$ss17DummyMainExecutorCScfsMc
-_$ss17DummyMainExecutorCScfsWP
-_$ss17DummyMainExecutorCfD
-_$ss17DummyMainExecutorCfd
-_$ss17DummyMainExecutorCs07RunLoopC0sMc
-_$ss17DummyMainExecutorCs07RunLoopC0sWP
-_$ss17DummyMainExecutorCs0bC0sMc
-_$ss17DummyMainExecutorCs0bC0sWP
-_$ss17DummyTaskExecutorC06isMainC0Sbvg
-_$ss17DummyTaskExecutorC06isMainC0SbvpMV
-_$ss17DummyTaskExecutorC7enqueueyys0C3JobVnF
-_$ss17DummyTaskExecutorCABycfC
-_$ss17DummyTaskExecutorCABycfCTj
-_$ss17DummyTaskExecutorCABycfCTq
-_$ss17DummyTaskExecutorCABycfc
-_$ss17DummyTaskExecutorCMa
-_$ss17DummyTaskExecutorCMm
-_$ss17DummyTaskExecutorCMn
-_$ss17DummyTaskExecutorCMo
-_$ss17DummyTaskExecutorCMu
-_$ss17DummyTaskExecutorCN
-_$ss17DummyTaskExecutorCScFsMc
-_$ss17DummyTaskExecutorCScFsWP
-_$ss17DummyTaskExecutorCSchsMc
-_$ss17DummyTaskExecutorCSchsWP
-_$ss17DummyTaskExecutorCfD
-_$ss17DummyTaskExecutorCfd
+_$ss18SchedulingExecutorMp
+_$ss18SchedulingExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTj
+_$ss18SchedulingExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTq
+_$ss18SchedulingExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTj
+_$ss18SchedulingExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTq
+_$ss18SchedulingExecutorPScFTb
+_$ss18SchedulingExecutorPsE7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lF
+_$ss18SchedulingExecutorPsE7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lF
+_$ss18SchedulingExecutorTL
 _$ss19AsyncFilterSequenceV04makeA8IteratorAB0E0Vyx_GyF
 _$ss19AsyncFilterSequenceV10isIncludedySb7ElementQzYacvg
 _$ss19AsyncFilterSequenceV10isIncludedySb7ElementQzYacvpMV
@@ -707,15 +653,6 @@ _$ss19DiscardingTaskGroupV9cancelAllyyF
 _$ss19DiscardingTaskGroupVMa
 _$ss19DiscardingTaskGroupVMn
 _$ss19DiscardingTaskGroupVN
-_$ss19SchedulableExecutorMp
-_$ss19SchedulableExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTj
-_$ss19SchedulableExecutorP7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lFTq
-_$ss19SchedulableExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTj
-_$ss19SchedulableExecutorP7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lFTq
-_$ss19SchedulableExecutorPScFTb
-_$ss19SchedulableExecutorPsE7enqueue_2at9tolerance5clockys0B3JobVn_7InstantQyd__8DurationQyd__Sgqd__ts5ClockRd__lF
-_$ss19SchedulableExecutorPsE7enqueue_5after9tolerance5clockys0B3JobVn_8DurationQyd__AJSgqd__ts5ClockRd__lF
-_$ss19SchedulableExecutorTL
 _$ss19UnownedTaskExecutorV02asbC0Sch_pSgyF
 _$ss19UnownedTaskExecutorVyABxhcSchRzlufC
 _$ss20AsyncFlatMapSequenceV04makeA8IteratorAB0F0Vyxq__GyF
@@ -747,39 +684,6 @@ _$ss20AsyncFlatMapSequenceVMa
 _$ss20AsyncFlatMapSequenceVMn
 _$ss20AsyncFlatMapSequenceV_9transformAByxq_Gx_q_7ElementQzYactcfC
 _$ss20AsyncFlatMapSequenceVyxq_GScisMc
-_$ss20DispatchMainExecutorC02isbC0Sbvg
-_$ss20DispatchMainExecutorC02isbC0SbvpMV
-_$ss20DispatchMainExecutorC13asSchedulables0eC0_pSgvg
-_$ss20DispatchMainExecutorC13asSchedulables0eC0_pSgvpMV
-_$ss20DispatchMainExecutorC13checkIsolatedyyF
-_$ss20DispatchMainExecutorC3runyyKFTj
-_$ss20DispatchMainExecutorC3runyyKFTq
-_$ss20DispatchMainExecutorC4stopyyFTj
-_$ss20DispatchMainExecutorC4stopyyFTq
-_$ss20DispatchMainExecutorC7enqueue_2at9tolerance5clockys0C3JobVn_7InstantQz8DurationQzSgxts5ClockRzlF
-_$ss20DispatchMainExecutorC7enqueueyys0C3JobVnF
-_$ss20DispatchMainExecutorCABycfC
-_$ss20DispatchMainExecutorCABycfCTj
-_$ss20DispatchMainExecutorCABycfCTq
-_$ss20DispatchMainExecutorCABycfc
-_$ss20DispatchMainExecutorCMa
-_$ss20DispatchMainExecutorCMm
-_$ss20DispatchMainExecutorCMn
-_$ss20DispatchMainExecutorCMo
-_$ss20DispatchMainExecutorCMu
-_$ss20DispatchMainExecutorCN
-_$ss20DispatchMainExecutorCScFsMc
-_$ss20DispatchMainExecutorCScFsWP
-_$ss20DispatchMainExecutorCScfsMc
-_$ss20DispatchMainExecutorCScfsWP
-_$ss20DispatchMainExecutorCfD
-_$ss20DispatchMainExecutorCfd
-_$ss20DispatchMainExecutorCs011SchedulableC0sMc
-_$ss20DispatchMainExecutorCs011SchedulableC0sWP
-_$ss20DispatchMainExecutorCs07RunLoopC0sMc
-_$ss20DispatchMainExecutorCs07RunLoopC0sWP
-_$ss20DispatchMainExecutorCs0bC0sMc
-_$ss20DispatchMainExecutorCs0bC0sWP
 _$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lF
 _$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lFTu
 _$ss21withUnsafeCurrentTask4bodyxxSctSgKXE_tKlF
@@ -915,31 +819,51 @@ _$ss24AsyncThrowingMapSequenceVMa
 _$ss24AsyncThrowingMapSequenceVMn
 _$ss24AsyncThrowingMapSequenceV_9transformAByxq_Gx_q_7ElementQzYaKctcfC
 _$ss24AsyncThrowingMapSequenceVyxq_GScisMc
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvgTj
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvgTq
-_$ss26DispatchGlobalTaskExecutorC06isMainD0SbvpMV
-_$ss26DispatchGlobalTaskExecutorC7enqueue_2at9tolerance5clockys0D3JobVn_7InstantQz8DurationQzSgxts5ClockRzlFTj
-_$ss26DispatchGlobalTaskExecutorC7enqueue_2at9tolerance5clockys0D3JobVn_7InstantQz8DurationQzSgxts5ClockRzlFTq
-_$ss26DispatchGlobalTaskExecutorC7enqueueyys0D3JobVnFTj
-_$ss26DispatchGlobalTaskExecutorC7enqueueyys0D3JobVnFTq
-_$ss26DispatchGlobalTaskExecutorCABycfC
-_$ss26DispatchGlobalTaskExecutorCABycfCTj
-_$ss26DispatchGlobalTaskExecutorCABycfCTq
-_$ss26DispatchGlobalTaskExecutorCABycfc
-_$ss26DispatchGlobalTaskExecutorCMa
-_$ss26DispatchGlobalTaskExecutorCMm
-_$ss26DispatchGlobalTaskExecutorCMn
-_$ss26DispatchGlobalTaskExecutorCMo
-_$ss26DispatchGlobalTaskExecutorCMu
-_$ss26DispatchGlobalTaskExecutorCN
-_$ss26DispatchGlobalTaskExecutorCScFsMc
-_$ss26DispatchGlobalTaskExecutorCScFsWP
-_$ss26DispatchGlobalTaskExecutorCSchsMc
-_$ss26DispatchGlobalTaskExecutorCSchsWP
-_$ss26DispatchGlobalTaskExecutorCfD
-_$ss26DispatchGlobalTaskExecutorCfd
-_$ss26DispatchGlobalTaskExecutorCs011SchedulableD0sMc
-_$ss26DispatchGlobalTaskExecutorCs011SchedulableD0sWP
+_$ss25UnimplementedMainExecutorC02isbC0Sbvg
+_$ss25UnimplementedMainExecutorC02isbC0SbvpMV
+_$ss25UnimplementedMainExecutorC13checkIsolatedyyF
+_$ss25UnimplementedMainExecutorC3runyyKF
+_$ss25UnimplementedMainExecutorC4stopyyF
+_$ss25UnimplementedMainExecutorC7enqueueyys0C3JobVnF
+_$ss25UnimplementedMainExecutorCABycfC
+_$ss25UnimplementedMainExecutorCABycfCTj
+_$ss25UnimplementedMainExecutorCABycfCTq
+_$ss25UnimplementedMainExecutorCABycfc
+_$ss25UnimplementedMainExecutorCMa
+_$ss25UnimplementedMainExecutorCMm
+_$ss25UnimplementedMainExecutorCMn
+_$ss25UnimplementedMainExecutorCMo
+_$ss25UnimplementedMainExecutorCMu
+_$ss25UnimplementedMainExecutorCN
+_$ss25UnimplementedMainExecutorCScFsMc
+_$ss25UnimplementedMainExecutorCScFsWP
+_$ss25UnimplementedMainExecutorCScfsMc
+_$ss25UnimplementedMainExecutorCScfsWP
+_$ss25UnimplementedMainExecutorCfD
+_$ss25UnimplementedMainExecutorCfd
+_$ss25UnimplementedMainExecutorCs07RunLoopC0sMc
+_$ss25UnimplementedMainExecutorCs07RunLoopC0sWP
+_$ss25UnimplementedMainExecutorCs0bC0sMc
+_$ss25UnimplementedMainExecutorCs0bC0sWP
+_$ss25UnimplementedTaskExecutorC06isMainC0Sbvg
+_$ss25UnimplementedTaskExecutorC06isMainC0SbvpMV
+_$ss25UnimplementedTaskExecutorC7enqueueyys0C3JobVnF
+_$ss25UnimplementedTaskExecutorCABycfC
+_$ss25UnimplementedTaskExecutorCABycfCTj
+_$ss25UnimplementedTaskExecutorCABycfCTq
+_$ss25UnimplementedTaskExecutorCABycfc
+_$ss25UnimplementedTaskExecutorCMa
+_$ss25UnimplementedTaskExecutorCMm
+_$ss25UnimplementedTaskExecutorCMn
+_$ss25UnimplementedTaskExecutorCMo
+_$ss25UnimplementedTaskExecutorCMu
+_$ss25UnimplementedTaskExecutorCN
+_$ss25UnimplementedTaskExecutorCScFsMc
+_$ss25UnimplementedTaskExecutorCScFsWP
+_$ss25UnimplementedTaskExecutorCSchsMc
+_$ss25UnimplementedTaskExecutorCSchsWP
+_$ss25UnimplementedTaskExecutorCfD
+_$ss25UnimplementedTaskExecutorCfd
 _$ss27AsyncThrowingFilterSequenceV04makeA8IteratorAB0F0Vyx_GyF
 _$ss27AsyncThrowingFilterSequenceV10isIncludedySb7ElementQzYaKcvg
 _$ss27AsyncThrowingFilterSequenceV10isIncludedySb7ElementQzYaKcvpMV
@@ -1104,29 +1028,21 @@ _$ss5ClockP17minimumResolution8DurationQzvgTj
 _$ss5ClockP17minimumResolution8DurationQzvgTq
 _$ss5ClockP3now7InstantQzvgTj
 _$ss5ClockP3now7InstantQzvgTq
+_$ss5ClockP3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtFTj
+_$ss5ClockP3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtFTq
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTj
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTjTu
 _$ss5ClockP5sleep5until9tolerancey7InstantQz_8DurationQzSgtYaKFTq
-_$ss5ClockP6traitss0A6TraitsVvgTj
-_$ss5ClockP6traitss0A6TraitsVvgTq
 _$ss5ClockP7InstantAB_s0B8ProtocolTn
-_$ss5ClockP7convert4from8DurationQzSgsAEV_tFTj
-_$ss5ClockP7convert4from8DurationQzSgsAEV_tFTq
-_$ss5ClockP7convert4froms8DurationVSgAEQz_tFTj
-_$ss5ClockP7convert4froms8DurationVSgAEQz_tFTq
-_$ss5ClockP7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lFTj
-_$ss5ClockP7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lFTq
-_$ss5ClockPsE6traitss0A6TraitsVvg
-_$ss5ClockPsE6traitss0A6TraitsVvpMV
-_$ss5ClockPsE7convert4from8DurationQzSgsAEV_tF
-_$ss5ClockPsE7convert4froms8DurationVSgAEQz_tF
-_$ss5ClockPsE7convert7instant4from7InstantQzSgAFQyd___qd__tsAARd__lF
+_$ss5ClockP7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lFTj
+_$ss5ClockP7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lFTq
+_$ss5ClockPsE3run_2at9toleranceys11ExecutorJobVn_7InstantQz8DurationQzSgtF
+_$ss5ClockPsE7enqueue_2on2at9toleranceys11ExecutorJobVn_qd__7InstantQz8DurationQzSgtScFRd__lF
 _$ss5ClockPsE7measurey8DurationQzyyKXEKF
 _$ss5ClockPsE7measurey8DurationQzyyYaKXEYaKF
 _$ss5ClockPsE7measurey8DurationQzyyYaKXEYaKFTu
 _$ss5ClockPss010ContinuousA0VRszrlE10continuousADvgZ
 _$ss5ClockPss010SuspendingA0VRszrlE10suspendingADvgZ
-_$ss5ClockPss8DurationVACRtzrlE7convert4fromADSgAD_tF
 _$ss5ClockTL
 _$ss6_first_5where7ElementQzSgx_SbADYaKXEtYaKSciRzlF
 _$ss6_first_5where7ElementQzSgx_SbADYaKXEtYaKSciRzlFTu
@@ -1160,6 +1076,7 @@ _$ss9TaskLocalCyxGs23CustomStringConvertiblesMc
 _$ss9_contains_5whereSbx_Sb7ElementQzYaKXEtYaKSciRzlF
 _$ss9_contains_5whereSbx_Sb7ElementQzYaKXEtYaKSciRzlFTu
 __swift_concurrency_debug_asyncTaskMetadata
+__swift_concurrency_debug_asyncTaskSize
 __swift_concurrency_debug_asyncTaskSlabMetadata
 __swift_concurrency_debug_future_adapter
 __swift_concurrency_debug_jobMetadata
@@ -1167,6 +1084,7 @@ __swift_concurrency_debug_non_future_adapter
 __swift_concurrency_debug_supportsPriorityEscalation
 __swift_concurrency_debug_task_future_wait_resume_adapter
 __swift_concurrency_debug_task_wait_throwing_resume_adapter
+__swift_createJobForTestingOnly
 _swift_asyncLet_begin
 _swift_asyncLet_consume
 _swift_asyncLet_consume_throwing
diff --git a/test/abi/macOS/arm64/concurrency.swift b/test/abi/macOS/arm64/concurrency.swift
index f447472f26a50..f847cef841826 100644
--- a/test/abi/macOS/arm64/concurrency.swift
+++ b/test/abi/macOS/arm64/concurrency.swift
@@ -388,28 +388,21 @@ Added: _$ss33withTaskPriorityEscalationHandler9operation02onC9Escalated9isolatio
 Added: _$sScTss5NeverORszABRs_rlE4nameSSSgvgZ
 Added: _$sScTss5NeverORszABRs_rlE4nameSSSgvpZMV
 Added: _swift_task_getCurrentTaskName
-Added: _$sScG22startTaskSynchronously4name8priority9operationySSSg_ScPSgxyYacntF
-Added: _$sScG37startTaskSynchronouslyUnlessCancelled4name8priority9operationySSSg_ScPSgxyYacntF
-Added: _$sScTss5Error_pRs_rlE18startSynchronously4name8priority_ScTyxsAA_pGSSSg_ScPSgxyYaKcntFZ
-Added: _$sScTss5NeverORs_rlE18startSynchronously4name8priority_ScTyxABGSSSg_ScPSgxyYaKcntFZ
-Added: _$sScg22startTaskSynchronously4name8priority9operationySSSg_ScPSgxyYaKcntF
-Added: _$sScg37startTaskSynchronouslyUnlessCancelled4name8priority9operationySSSg_ScPSgxyYaKcntF
-Added: _$ss19DiscardingTaskGroupV05startB13Synchronously4name8priority9operationySSSg_ScPSgyyYacntF
-Added: _$ss19DiscardingTaskGroupV05startB28SynchronouslyUnlessCancelled4name8priority9operationySSSg_ScPSgyyYacntF
-Added: _$ss27ThrowingDiscardingTaskGroupV05startC13Synchronously4name8priority9operationySSSg_ScPSgyyYaKcntF
-Added: _$ss27ThrowingDiscardingTaskGroupV05startC28SynchronouslyUnlessCancelled4name8priority9operationySSSg_ScPSgyyYaKcntF
-
-Added: _swift_task_startSynchronously
 
+// startSynchronously, immediate, addImmediateTask{UnlessCancelled}
+Added: _swift_task_immediate
+
+// isIsolatingCurrentContext
 Added: _swift_task_invokeSwiftIsIsolatingCurrentContext
 Added: _swift_task_isIsolatingCurrentContext
 Added: _swift_task_isIsolatingCurrentContext_hook
-Added: _$sScf25isIsolatingCurrentContextSbyFTj
-Added: _$sScf25isIsolatingCurrentContextSbyFTq
-Added: _$sScfsE25isIsolatingCurrentContextSbyF
+Added: _$sScfsE25isIsolatingCurrentContextSbSgyF
+Added: _$sScf25isIsolatingCurrentContextSbSgyFTj
+Added: _$sScf25isIsolatingCurrentContextSbSgyFTq
 
 // CoroutineAccessors
 Added: _swift_task_dealloc_through
 
-// SwiftSettings
-Added: _$ss12SwiftSettingVsE16defaultIsolationyABScA_pXpSgFZ
+// Clock systemEpochs
+Added: _$ss15ContinuousClockV11systemEpochAB7InstantVvpMV
+Added: _$ss15SuspendingClockV11systemEpochAB7InstantVvpMV
diff --git a/test/abi/macOS/arm64/observation.swift b/test/abi/macOS/arm64/observation.swift
index cc193b65629fe..bcbfbd6b9ef85 100644
--- a/test/abi/macOS/arm64/observation.swift
+++ b/test/abi/macOS/arm64/observation.swift
@@ -42,3 +42,48 @@ Added: _$s11Observation0A8TrackingV7changeds10AnyKeyPathCSgvg
 
 // property descriptor for Observation.ObservationTracking.changed : Swift.AnyKeyPath?
 Added: _$s11Observation0A8TrackingV7changeds10AnyKeyPathCSgvpMV
+
+// static Observation.Observations.untilFinished(@isolated(any) @Sendable () throws(B) -> Observation.Observations<A, B>.Iteration) -> Observation.Observations<A, B>
+Added: _$s11Observation12ObservationsV13untilFinishedyACyxq_GAC9IterationOyxq__GyYbq_YKYAcFZ
+
+// Observation.Observations.makeAsyncIterator() -> Observation.Observations<A, B>.Iterator
+Added: _$s11Observation12ObservationsV17makeAsyncIteratorAC0E0Vyxq__GyF
+
+// Observation.Observations.Iterator.next(isolation: isolated Swift.Actor?) async throws(B) -> A?
+Added: _$s11Observation12ObservationsV8IteratorV4next9isolationxSgScA_pSgYi_tYaq_YKF
+
+// async function pointer to Observation.Observations.Iterator.next(isolation: isolated Swift.Actor?) async throws(B) -> A?
+Added: _$s11Observation12ObservationsV8IteratorV4next9isolationxSgScA_pSgYi_tYaq_YKFTu
+
+// type metadata accessor for Observation.Observations.Iterator
+Added: _$s11Observation12ObservationsV8IteratorVMa
+
+// nominal type descriptor for Observation.Observations.Iterator
+Added: _$s11Observation12ObservationsV8IteratorVMn
+
+// protocol conformance descriptor for Observation.Observations<A, B>.Iterator : Swift.AsyncIteratorProtocol in Observation
+Added: _$s11Observation12ObservationsV8IteratorVyxq__GScIAAMc
+
+// enum case for Observation.Observations.Iteration.next<A, B where A: Swift.Sendable, B: Swift.Error>(Observation.Observations<A, B>.Iteration.Type) -> (A) -> Observation.Observations<A, B>.Iteration
+Added: _$s11Observation12ObservationsV9IterationO4nextyAEyxq__GxcAGms8SendableRzs5ErrorR_r0_lFWC
+
+// enum case for Observation.Observations.Iteration.finish<A, B where A: Swift.Sendable, B: Swift.Error>(Observation.Observations<A, B>.Iteration.Type) -> Observation.Observations<A, B>.Iteration
+Added: _$s11Observation12ObservationsV9IterationO6finishyAEyxq__GAGms8SendableRzs5ErrorR_r0_lFWC
+
+// type metadata accessor for Observation.Observations.Iteration
+Added: _$s11Observation12ObservationsV9IterationOMa
+
+// nominal type descriptor for Observation.Observations.Iteration
+Added: _$s11Observation12ObservationsV9IterationOMn
+
+// type metadata accessor for Observation.Observations
+Added: _$s11Observation12ObservationsVMa
+
+// nominal type descriptor for Observation.Observations
+Added: _$s11Observation12ObservationsVMn
+
+// Observation.Observations.init(@isolated(any) @Sendable () throws(B) -> A) -> Observation.Observations<A, B>
+Added: _$s11Observation12ObservationsVyACyxq_GxyYbq_YKYAccfC
+
+// protocol conformance descriptor for Observation.Observations<A, B> : Swift.AsyncSequence in Observation
+Added: _$s11Observation12ObservationsVyxq_GSciAAMc
diff --git a/test/abi/macOS/arm64/stdlib.swift b/test/abi/macOS/arm64/stdlib.swift
index 5a6efa986be8f..f0e2cbd847562 100644
--- a/test/abi/macOS/arm64/stdlib.swift
+++ b/test/abi/macOS/arm64/stdlib.swift
@@ -770,6 +770,7 @@ Added: _$ss7UnicodeO5UTF16O27encodedReplacementCharacters11_UIntBufferVys6UInt16
 Added: _$ss7UnicodeO5UTF32O27encodedReplacementCharacters15CollectionOfOneVys6UInt32VGvpZMV
 Added: _$sSo19_SwiftStdlibVersionasE6v6_1_0ABvpZMV
 Added: _$sSo19_SwiftStdlibVersionasE6v6_2_0ABvpZMV
+Added: _$sSo19_SwiftStdlibVersionasE6v6_3_0ABvpZMV
 Added: _$sSBsE5radixSivpZMV
 Added: _$sSFsE8ulpOfOnexvpZMV
 Added: _$sSUsE8isSignedSbvpZMV
@@ -795,31 +796,128 @@ Added: _$sSS5IndexVs28CustomDebugStringConvertiblesWP
 Added: _$ss4SpanVMa
 Added: _$ss4SpanVMn
 Added: _$ss4SpanVsRi_zrlE6_countSivg
-Added: _$ss4SpanVsRi_zrlE6_countSivpMV
 Added: _$ss4SpanVsRi_zrlE8_pointerSVSgvg
-Added: _$ss4SpanVsRi_zrlE8_pointerSVSgvpMV
-Added: _$ss4SpanVsRi_zrlE5countSivpMV
-Added: _$ss4SpanVsRi_zrlE7indicesSnySiGvpMV
-Added: _$ss4SpanVsRi_zrlE7isEmptySbvpMV
-Added: _$ss4SpanVss15BitwiseCopyableRzlE9uncheckedxSi_tcipMV
-Added: _$ss4SpanVss15BitwiseCopyableRzlEyxSicipMV
-Added: _$ss7RawSpanV11byteOffsetsSnySiGvpMV
 Added: _$ss7RawSpanV6_countSivg
-Added: _$ss7RawSpanV6_countSivpMV
-Added: _$ss7RawSpanV7isEmptySbvpMV
 Added: _$ss7RawSpanV8_pointerSVSgvg
-Added: _$ss7RawSpanV8_pointerSVSgvpMV
-Added: _$ss7RawSpanV9byteCountSivpMV
 Added: _$ss7RawSpanVMa
 Added: _$ss7RawSpanVMn
 Added: _$ss7RawSpanVN
 
+// SE-0464 UTF8Span
+Added: _$sSS7copyingSSs8UTF8SpanV_tcfC
+Added: _$sSS8utf8Spans04UTF8B0Vvg
+Added: _$sSs8utf8Spans04UTF8B0Vvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11byteOffsetsSnySiGvM
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11byteOffsetsSnySiGvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11byteOffsetsSnySiGvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11byteOffsetsSnySiGvs
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11descriptionSSvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11descriptionSSvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV2eeoiySbAF_AFtFZ
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV11descriptionSSvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV11descriptionSSvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV15truncatedScalarAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV20overlongEncodingByteAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV22surrogateCodePointByteAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV26unexpectedContinuationByteAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV32invalidNonSurrogateCodePointByteAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValueAHSgs5UInt8V_tcfC
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValues5UInt8VvM
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValues5UInt8Vvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValues5UInt8VvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValues5UInt8Vvs
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVMa
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVMn
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVN
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSHsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSHsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSQsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSQsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSYsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSYsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVs0D0sMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVs0D0sWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVs23CustomStringConvertiblesMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVs23CustomStringConvertiblesWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4hash4intoys6HasherVz_tF
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4kindAF4KindVvM
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4kindAF4KindVvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4kindAF4KindVvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4kindAF4KindVvs
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV9hashValueSivg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV9hashValueSivpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVMa
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVMn
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVN
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVSHsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVSHsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVSQsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVSQsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVs0D0sMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVs0D0sWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVs23CustomStringConvertiblesMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVs23CustomStringConvertiblesWP
+Added: _$ss7UnicodeO4UTF8O15_checkAllErrorsySayAD15ValidationErrorVGxSTRzs5UInt8V7ElementRtzlFZ
+Added: _$ss8UTF8SpanV9unchecked12isKnownASCIIABs0B0Vys5UInt8VG_SbtcfC
+Added: _$ss8UTF8SpanV10validatingABs0B0Vys5UInt8VG_ts7UnicodeO0A0O15ValidationErrorVYKcfC
+Added: _$ss8UTF8SpanV11checkForNFC10quickCheckS2b_tF
+Added: _$ss8UTF8SpanV13checkForASCIISbyF
+Added: _$ss8UTF8SpanV14_countAndFlagss6UInt64VvM
+Added: _$ss8UTF8SpanV14_countAndFlagss6UInt64Vvg
+Added: _$ss8UTF8SpanV14_countAndFlagss6UInt64Vvs
+Added: _$ss8UTF8SpanV17CharacterIteratorV11skipForward2byS2i_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV11skipForwardSiyF
+Added: _$ss8UTF8SpanV17CharacterIteratorV21currentCodeUnitOffsetSivg
+Added: _$ss8UTF8SpanV17CharacterIteratorV4nextSJSgyF
+Added: _$ss8UTF8SpanV17CharacterIteratorV5reset20roundingForwardsFromySi_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV5reset21roundingBackwardsFromySi_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV5reset11toUncheckedySi_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV6prefixAByF
+Added: _$ss8UTF8SpanV17CharacterIteratorV6suffixAByF
+Added: _$ss8UTF8SpanV17CharacterIteratorV8previousSJSgyF
+Added: _$ss8UTF8SpanV17CharacterIteratorV8skipBack2byS2i_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV8skipBackSiyF
+Added: _$ss8UTF8SpanV17CharacterIteratorV9codeUnitsABvg
+Added: _$ss8UTF8SpanV17CharacterIteratorVMa
+Added: _$ss8UTF8SpanV17CharacterIteratorVMn
+Added: _$ss8UTF8SpanV17CharacterIteratorVN
+Added: _$ss8UTF8SpanV17CharacterIteratorVyAdBcfC
+Added: _$ss8UTF8SpanV18_unsafeBaseAddressSVSgvM
+Added: _$ss8UTF8SpanV18_unsafeBaseAddressSVSgvg
+Added: _$ss8UTF8SpanV18_unsafeBaseAddressSVSgvs
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV11skipForward2byS2i_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV11skipForwardSiyF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV21currentCodeUnitOffsetSivg
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV4nexts0C0O0D0VSgyF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV5reset20roundingForwardsFromySi_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV5reset21roundingBackwardsFromySi_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV5reset11toUncheckedySi_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV6prefixAByF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV6suffixAByF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV8previouss0C0O0D0VSgyF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV8skipBack2byS2i_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV8skipBackSiyF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV9codeUnitsABvg
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorVMa
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorVMn
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorVN
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorVyAdBcfC
+Added: _$ss8UTF8SpanV21isCanonicallyLessThanySbABF
+Added: _$ss8UTF8SpanV21makeCharacterIteratorAB0dE0VyF
+Added: _$ss8UTF8SpanV23isCanonicallyEquivalent2toSbAB_tF
+Added: _$ss8UTF8SpanV25makeUnicodeScalarIteratorAB0deF0VyF
+Added: _$ss8UTF8SpanV4spans0B0Vys5UInt8VGvg
+Added: _$ss8UTF8SpanV7isEmptySbvg
+Added: _$ss8UTF8SpanVMa
+Added: _$ss8UTF8SpanVMn
+Added: _$ss8UTF8SpanVN
+
+
 // SE-0467 MutableSpan and MutableRawSpan
 Added: _$ss11MutableSpanVMa
 Added: _$ss11MutableSpanVMn
 Added: _$ss11MutableSpanVsRi_zrlE6_countSivg
 Added: _$ss11MutableSpanVsRi_zrlE8_pointerSvSgvg
-Added: _$ss11MutableSpanVsRi_zrlE10_uncheckedAByxGSryxG_tcfC
 Added: _$ss14MutableRawSpanV6_countSivg
 Added: _$ss14MutableRawSpanV8_pointerSvSgvg
 Added: _$ss14MutableRawSpanVMa
@@ -827,25 +925,25 @@ Added: _$ss14MutableRawSpanVMn
 Added: _$ss14MutableRawSpanVN
 
 // SE-0456 Span-providing properties
-Added: _$sSRsRi_zrlE4spans4SpanVyxGvpMV
-Added: _$sSW5bytess7RawSpanVvpMV
-Added: _$sSa4spans4SpanVyxGvpMV
-Added: _$sSrsRi_zrlE4spans4SpanVyxGvpMV
-Added: _$sSw5bytess7RawSpanVvpMV
-Added: _$ss10ArraySliceV4spans4SpanVyxGvpMV
-Added: _$ss13KeyValuePairsV4spans4SpanVyx3key_q_5valuetGvpMV
-Added: _$ss15CollectionOfOneV4spans4SpanVyxGvpMV
-Added: _$ss15ContiguousArrayV4spans4SpanVyxGvpMV
-Added: _$ss4SpanVss15BitwiseCopyableRzlE5bytess03RawA0VvpMV
 Added: _$sSS8UTF8ViewV4spans4SpanVys5UInt8VGvg
-Added: _$sSS8UTF8ViewV4spans4SpanVys5UInt8VGvpMV
 Added: _$sSs8UTF8ViewV4spans4SpanVys5UInt8VGvg
-Added: _$sSs8UTF8ViewV4spans4SpanVys5UInt8VGvpMV
 
-// SE-0467 mutableSpan properties
-Added: _$sSa11mutableSpans07MutableB0VyxGvr
-Added: _$ss10ArraySliceV11mutableSpans07MutableD0VyxGvr
-Added: _$ss15ContiguousArrayV11mutableSpans07MutableD0VyxGvr
+// OutputSpan
+Added: _$ss10OutputSpanVMa
+Added: _$ss10OutputSpanVMn
+Added: _$ss10OutputSpanVsRi_zrlE6_countSivM
+Added: _$ss10OutputSpanVsRi_zrlE6_countSivg
+Added: _$ss10OutputSpanVsRi_zrlE6_countSivs
+Added: _$ss10OutputSpanVsRi_zrlE8_pointerSvSgvg
+Added: _$ss10OutputSpanVsRi_zrlE8capacitySivg
+Added: _$ss13OutputRawSpanV6_countSivM
+Added: _$ss13OutputRawSpanV6_countSivg
+Added: _$ss13OutputRawSpanV6_countSivs
+Added: _$ss13OutputRawSpanV8_pointerSvSgvg
+Added: _$ss13OutputRawSpanV8capacitySivg
+Added: _$ss13OutputRawSpanVMa
+Added: _$ss13OutputRawSpanVMn
+Added: _$ss13OutputRawSpanVN
 
 // _SwiftifyInfo enum for _SwiftifyImports macro
 Added: _$ss13_SwiftifyExprO5paramyABSicABmFWC
@@ -886,9 +984,6 @@ Added: _$ss11InlineArrayVMa
 // InlineArray nominal type descriptor
 Added: _$ss11InlineArrayVMn
 
-// InlineArray.count property descriptor
-Added: _$ss11InlineArrayVsRi__rlE5countSivpZMV
-
 // InlineArray._storage _read accessor
 Added: _$ss11InlineArrayVsRi__rlE8_storagexq_BVvr
 
@@ -938,12 +1033,6 @@ Added: _swift_ConformanceExecutionContextSize
 Added: _swift_conformsToProtocolWithExecutionContext
 Added: _swift_isInConformanceExecutionContext
 
-// Swift Settings
-Added: _$ss12SwiftSettingVABycfC
-Added: _$ss12SwiftSettingVMa
-Added: _$ss12SwiftSettingVMn
-Added: _$ss12SwiftSettingVN
-
 // EnumeratedSequence Collection conformances
 Added: _$ss18EnumeratedSequenceVyxGSksSkRzrlMc
 Added: _$ss18EnumeratedSequenceVyxGSlsSlRzrlMc
@@ -966,3 +1055,91 @@ Added: _$ss18EnumeratedSequenceVyxGSKsSkRzrlMc
 
 // Indirect tagged string creation
 Added: __swift_stdlib_CreateIndirectTaggedPointerString
+
+// Span backward deployment
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss11MutableSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss11MutableSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss11MutableSpanVsRi_zrlE6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss11MutableSpanVsRi_zrlE8_pointerSvSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanV6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanV8_pointerSvSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanVN$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE6_countSivM$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE6_countSivs$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE8_pointerSvSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE8capacitySivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV6_countSivM$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV6_countSivs$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV8_pointerSvSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV8capacitySivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanVN$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss4SpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss4SpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss4SpanVsRi_zrlE6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss4SpanVsRi_zrlE8_pointerSVSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanV6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanV8_pointerSVSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanVN$
+
+// Duration.nanoseconds(_:)
+Added: _$ss8DurationV11nanosecondsyABSdFZ
+
+// var InlineArray._storage
+Added: _$ss11InlineArrayVsRi__rlE8_storagexq_BVvM
+Added: _$ss11InlineArrayVsRi__rlE8_storagexq_BVvs
+
+// rdar://151628396: Retroactively give property descriptors to conditionally-copyable/escapable properties
+Added: _$ss11InlineArrayVsRi__rlE10startIndexSivpMV
+Added: _$ss11InlineArrayVsRi__rlE5countSivpMV
+Added: _$ss11InlineArrayVsRi__rlE7_bufferSRyq_GvpMV
+Added: _$ss11InlineArrayVsRi__rlE7indicesSnySiGvpMV
+Added: _$ss11InlineArrayVsRi__rlE7isEmptySbvpMV
+Added: _$ss11InlineArrayVsRi__rlE8_addressSPyq_GvpMV
+Added: _$ss11InlineArrayVsRi__rlE8endIndexSivpMV
+Added: _$ss8UTF8SpanV10_countMasks6UInt64VvpZMV
+Added: _$ss8UTF8SpanV10_flagsMasks6UInt64VvpZMV
+Added: _$ss8UTF8SpanV7_nfcBits6UInt64VvpZMV
+Added: _$ss8UTF8SpanV9_asciiBits6UInt64VvpZMV
+
+// printing foreign reference types requires a new displayStyle: .foreign
+Added: _$ss6MirrorV12DisplayStyleO16foreignReferenceyA2DmFWC
+
+// var InlineArray._protectedBuffer
+// var InlineArray._protectedAddress
+Added: _$ss11InlineArrayVsRi__rlE16_protectedBufferSRyq_GvpMV
+Added: _$ss11InlineArrayVsRi__rlE17_protectedAddressSPyq_GvpMV
+
+// lengthOfBytes(using:)
+Added: __swift_stdlib_NSStringLengthOfBytesInEncodingTrampoline
+
+// Word breaking symbols exposed in 6.3
+Added: _$sSS10_wordIndex19somewhereAtOrBeforeSS0B0VAD_tF
+Added: _$ss7UnicodeO15_WordRecognizerV22hasCandidateBreakAtEndSbyF
+Added: _$ss7UnicodeO15_WordRecognizerV5afterAdB6ScalarV_tcfC
+Added: _$ss7UnicodeO15_WordRecognizerV8hasBreak6beforeSb12setCandidate_Sb07breakAtH0Sb0I4HeretAB6ScalarV_tF
+Added: _$ss7UnicodeO15_WordRecognizerVADycfC
+Added: _$ss7UnicodeO15_WordRecognizerVMa
+Added: _$ss7UnicodeO15_WordRecognizerVMn
+Added: _$ss7UnicodeO15_WordRecognizerVN
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerV18hasGuaranteedBreak5afterSb12setCandidate_Sb07breakAtK0Sb0L4HeretAB6ScalarV_tF
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerV6beforeAdB6ScalarV_tcfC
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerVMa
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerVMn
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerVN
+// Obsolete/broken SPIs removed in 6.3
+Removed: _$sSS17_nearestWordIndex9atOrBelowSS0C0VAD_tF
+Removed: _$sSS10_wordIndex6beforeSS0B0VAD_tF
+
+// Internal info exposed for swift-inspect.
+Added: __swift_debug_allocationPoolSize
+Added: __swift_debug_metadataAllocatorPageSize
diff --git a/test/abi/macOS/x86_64/concurrency.swift b/test/abi/macOS/x86_64/concurrency.swift
index 219205d720458..b826dec8c0dbe 100644
--- a/test/abi/macOS/x86_64/concurrency.swift
+++ b/test/abi/macOS/x86_64/concurrency.swift
@@ -388,28 +388,21 @@ Added: _$ss33withTaskPriorityEscalationHandler9operation02onC9Escalated9isolatio
 Added: _$sScTss5NeverORszABRs_rlE4nameSSSgvgZ
 Added: _$sScTss5NeverORszABRs_rlE4nameSSSgvpZMV
 Added: _swift_task_getCurrentTaskName
-Added: _$sScG22startTaskSynchronously4name8priority9operationySSSg_ScPSgxyYacntF
-Added: _$sScG37startTaskSynchronouslyUnlessCancelled4name8priority9operationySSSg_ScPSgxyYacntF
-Added: _$sScTss5Error_pRs_rlE18startSynchronously4name8priority_ScTyxsAA_pGSSSg_ScPSgxyYaKcntFZ
-Added: _$sScTss5NeverORs_rlE18startSynchronously4name8priority_ScTyxABGSSSg_ScPSgxyYaKcntFZ
-Added: _$sScg22startTaskSynchronously4name8priority9operationySSSg_ScPSgxyYaKcntF
-Added: _$sScg37startTaskSynchronouslyUnlessCancelled4name8priority9operationySSSg_ScPSgxyYaKcntF
-Added: _$ss19DiscardingTaskGroupV05startB13Synchronously4name8priority9operationySSSg_ScPSgyyYacntF
-Added: _$ss19DiscardingTaskGroupV05startB28SynchronouslyUnlessCancelled4name8priority9operationySSSg_ScPSgyyYacntF
-Added: _$ss27ThrowingDiscardingTaskGroupV05startC13Synchronously4name8priority9operationySSSg_ScPSgyyYaKcntF
-Added: _$ss27ThrowingDiscardingTaskGroupV05startC28SynchronouslyUnlessCancelled4name8priority9operationySSSg_ScPSgyyYaKcntF
-
-Added: _swift_task_startSynchronously
 
+// startSynchronously, immediate, addImmediateTask{UnlessCancelled}
+Added: _swift_task_immediate
+
+// isIsolatingCurrentContext
 Added: _swift_task_invokeSwiftIsIsolatingCurrentContext
 Added: _swift_task_isIsolatingCurrentContext
 Added: _swift_task_isIsolatingCurrentContext_hook
-Added: _$sScf25isIsolatingCurrentContextSbyFTj
-Added: _$sScf25isIsolatingCurrentContextSbyFTq
-Added: _$sScfsE25isIsolatingCurrentContextSbyF
+Added: _$sScfsE25isIsolatingCurrentContextSbSgyF
+Added: _$sScf25isIsolatingCurrentContextSbSgyFTj
+Added: _$sScf25isIsolatingCurrentContextSbSgyFTq
 
 // CoroutineAccessors
 Added: _swift_task_dealloc_through
 
-// SwiftSettings
-Added: _$ss12SwiftSettingVsE16defaultIsolationyABScA_pXpSgFZ
+// Clock systemEpochs
+Added: _$ss15ContinuousClockV11systemEpochAB7InstantVvpMV
+Added: _$ss15SuspendingClockV11systemEpochAB7InstantVvpMV
diff --git a/test/abi/macOS/x86_64/observation.swift b/test/abi/macOS/x86_64/observation.swift
index 0c80ebce005a5..bcbfbd6b9ef85 100644
--- a/test/abi/macOS/x86_64/observation.swift
+++ b/test/abi/macOS/x86_64/observation.swift
@@ -1,10 +1,11 @@
 // RUN: %empty-directory(%t)
-// RUN: %llvm-nm -g --defined-only -f just-symbols %stdlib_dir/x86_64/libswiftObservation.dylib > %t/symbols
+// RUN: %llvm-nm -g --defined-only -f just-symbols %stdlib_dir/arm64/libswiftObservation.dylib > %t/symbols
 // RUN: %abi-symbol-checker %s %t/symbols
-// RUN: diff -u %S/../../Inputs/macOS/x86_64/observation/baseline %t/symbols
+// RUN: diff -u %S/../../Inputs/macOS/arm64/observation/baseline %t/symbols
 
 // REQUIRES: swift_stdlib_no_asserts
-// REQUIRES: STDLIB_VARIANT=macosx-x86_64
+// REQUIRES: STDLIB_VARIANT=macosx-arm64
+// REQUIRES: observation
 
 // *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment below.)
 
@@ -41,3 +42,48 @@ Added: _$s11Observation0A8TrackingV7changeds10AnyKeyPathCSgvg
 
 // property descriptor for Observation.ObservationTracking.changed : Swift.AnyKeyPath?
 Added: _$s11Observation0A8TrackingV7changeds10AnyKeyPathCSgvpMV
+
+// static Observation.Observations.untilFinished(@isolated(any) @Sendable () throws(B) -> Observation.Observations<A, B>.Iteration) -> Observation.Observations<A, B>
+Added: _$s11Observation12ObservationsV13untilFinishedyACyxq_GAC9IterationOyxq__GyYbq_YKYAcFZ
+
+// Observation.Observations.makeAsyncIterator() -> Observation.Observations<A, B>.Iterator
+Added: _$s11Observation12ObservationsV17makeAsyncIteratorAC0E0Vyxq__GyF
+
+// Observation.Observations.Iterator.next(isolation: isolated Swift.Actor?) async throws(B) -> A?
+Added: _$s11Observation12ObservationsV8IteratorV4next9isolationxSgScA_pSgYi_tYaq_YKF
+
+// async function pointer to Observation.Observations.Iterator.next(isolation: isolated Swift.Actor?) async throws(B) -> A?
+Added: _$s11Observation12ObservationsV8IteratorV4next9isolationxSgScA_pSgYi_tYaq_YKFTu
+
+// type metadata accessor for Observation.Observations.Iterator
+Added: _$s11Observation12ObservationsV8IteratorVMa
+
+// nominal type descriptor for Observation.Observations.Iterator
+Added: _$s11Observation12ObservationsV8IteratorVMn
+
+// protocol conformance descriptor for Observation.Observations<A, B>.Iterator : Swift.AsyncIteratorProtocol in Observation
+Added: _$s11Observation12ObservationsV8IteratorVyxq__GScIAAMc
+
+// enum case for Observation.Observations.Iteration.next<A, B where A: Swift.Sendable, B: Swift.Error>(Observation.Observations<A, B>.Iteration.Type) -> (A) -> Observation.Observations<A, B>.Iteration
+Added: _$s11Observation12ObservationsV9IterationO4nextyAEyxq__GxcAGms8SendableRzs5ErrorR_r0_lFWC
+
+// enum case for Observation.Observations.Iteration.finish<A, B where A: Swift.Sendable, B: Swift.Error>(Observation.Observations<A, B>.Iteration.Type) -> Observation.Observations<A, B>.Iteration
+Added: _$s11Observation12ObservationsV9IterationO6finishyAEyxq__GAGms8SendableRzs5ErrorR_r0_lFWC
+
+// type metadata accessor for Observation.Observations.Iteration
+Added: _$s11Observation12ObservationsV9IterationOMa
+
+// nominal type descriptor for Observation.Observations.Iteration
+Added: _$s11Observation12ObservationsV9IterationOMn
+
+// type metadata accessor for Observation.Observations
+Added: _$s11Observation12ObservationsVMa
+
+// nominal type descriptor for Observation.Observations
+Added: _$s11Observation12ObservationsVMn
+
+// Observation.Observations.init(@isolated(any) @Sendable () throws(B) -> A) -> Observation.Observations<A, B>
+Added: _$s11Observation12ObservationsVyACyxq_GxyYbq_YKYAccfC
+
+// protocol conformance descriptor for Observation.Observations<A, B> : Swift.AsyncSequence in Observation
+Added: _$s11Observation12ObservationsVyxq_GSciAAMc
diff --git a/test/abi/macOS/x86_64/stdlib.swift b/test/abi/macOS/x86_64/stdlib.swift
index fa65d16e98fd1..eaa92121c553c 100644
--- a/test/abi/macOS/x86_64/stdlib.swift
+++ b/test/abi/macOS/x86_64/stdlib.swift
@@ -751,6 +751,7 @@ Added: _$ss8SIMDMaskVss6SIMD64Vys5Int32VGRszrlE7allTrueAByAGGvpZMV
 Added: _$ss8SIMDMaskVss6SIMD64Vys5Int64VGRszrlE7allTrueAByAGGvpZMV
 Added: _$sSo19_SwiftStdlibVersionasE6v6_1_0ABvpZMV
 Added: _$sSo19_SwiftStdlibVersionasE6v6_2_0ABvpZMV
+Added: _$sSo19_SwiftStdlibVersionasE6v6_3_0ABvpZMV
 Added: _$ss7Float80V12signalingNaNABvpZMV
 Added: _$ss7Float80V13_exponentBiasSuvpZMV
 Added: _$ss7Float80V13_quietNaNMasks6UInt64VvpZMV
@@ -796,31 +797,128 @@ Added: _$sSS5IndexVs28CustomDebugStringConvertiblesWP
 Added: _$ss4SpanVMa
 Added: _$ss4SpanVMn
 Added: _$ss4SpanVsRi_zrlE6_countSivg
-Added: _$ss4SpanVsRi_zrlE6_countSivpMV
 Added: _$ss4SpanVsRi_zrlE8_pointerSVSgvg
-Added: _$ss4SpanVsRi_zrlE8_pointerSVSgvpMV
-Added: _$ss4SpanVsRi_zrlE5countSivpMV
-Added: _$ss4SpanVsRi_zrlE7indicesSnySiGvpMV
-Added: _$ss4SpanVsRi_zrlE7isEmptySbvpMV
-Added: _$ss4SpanVss15BitwiseCopyableRzlE9uncheckedxSi_tcipMV
-Added: _$ss4SpanVss15BitwiseCopyableRzlEyxSicipMV
-Added: _$ss7RawSpanV11byteOffsetsSnySiGvpMV
 Added: _$ss7RawSpanV6_countSivg
-Added: _$ss7RawSpanV6_countSivpMV
-Added: _$ss7RawSpanV7isEmptySbvpMV
 Added: _$ss7RawSpanV8_pointerSVSgvg
-Added: _$ss7RawSpanV8_pointerSVSgvpMV
-Added: _$ss7RawSpanV9byteCountSivpMV
 Added: _$ss7RawSpanVMa
 Added: _$ss7RawSpanVMn
 Added: _$ss7RawSpanVN
 
+// SE-0464 UTF8Span
+Added: _$sSS7copyingSSs8UTF8SpanV_tcfC
+Added: _$sSS8utf8Spans04UTF8B0Vvg
+Added: _$sSs8utf8Spans04UTF8B0Vvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11byteOffsetsSnySiGvM
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11byteOffsetsSnySiGvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11byteOffsetsSnySiGvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11byteOffsetsSnySiGvs
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11descriptionSSvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV11descriptionSSvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV2eeoiySbAF_AFtFZ
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV11descriptionSSvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV11descriptionSSvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV15truncatedScalarAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV20overlongEncodingByteAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV22surrogateCodePointByteAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV26unexpectedContinuationByteAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV32invalidNonSurrogateCodePointByteAHvpZMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValueAHSgs5UInt8V_tcfC
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValues5UInt8VvM
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValues5UInt8Vvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValues5UInt8VvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindV8rawValues5UInt8Vvs
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVMa
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVMn
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVN
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSHsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSHsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSQsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSQsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSYsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVSYsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVs0D0sMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVs0D0sWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVs23CustomStringConvertiblesMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4KindVs23CustomStringConvertiblesWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4hash4intoys6HasherVz_tF
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4kindAF4KindVvM
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4kindAF4KindVvg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4kindAF4KindVvpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV4kindAF4KindVvs
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV9hashValueSivg
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorV9hashValueSivpMV
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVMa
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVMn
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVN
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVSHsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVSHsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVSQsMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVSQsWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVs0D0sMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVs0D0sWP
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVs23CustomStringConvertiblesMc
+Added: _$ss7UnicodeO4UTF8O15ValidationErrorVs23CustomStringConvertiblesWP
+Added: _$ss7UnicodeO4UTF8O15_checkAllErrorsySayAD15ValidationErrorVGxSTRzs5UInt8V7ElementRtzlFZ
+Added: _$ss8UTF8SpanV9unchecked12isKnownASCIIABs0B0Vys5UInt8VG_SbtcfC
+Added: _$ss8UTF8SpanV10validatingABs0B0Vys5UInt8VG_ts7UnicodeO0A0O15ValidationErrorVYKcfC
+Added: _$ss8UTF8SpanV11checkForNFC10quickCheckS2b_tF
+Added: _$ss8UTF8SpanV13checkForASCIISbyF
+Added: _$ss8UTF8SpanV14_countAndFlagss6UInt64VvM
+Added: _$ss8UTF8SpanV14_countAndFlagss6UInt64Vvg
+Added: _$ss8UTF8SpanV14_countAndFlagss6UInt64Vvs
+Added: _$ss8UTF8SpanV17CharacterIteratorV11skipForward2byS2i_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV11skipForwardSiyF
+Added: _$ss8UTF8SpanV17CharacterIteratorV21currentCodeUnitOffsetSivg
+Added: _$ss8UTF8SpanV17CharacterIteratorV4nextSJSgyF
+Added: _$ss8UTF8SpanV17CharacterIteratorV5reset20roundingForwardsFromySi_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV5reset21roundingBackwardsFromySi_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV5reset11toUncheckedySi_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV6prefixAByF
+Added: _$ss8UTF8SpanV17CharacterIteratorV6suffixAByF
+Added: _$ss8UTF8SpanV17CharacterIteratorV8previousSJSgyF
+Added: _$ss8UTF8SpanV17CharacterIteratorV8skipBack2byS2i_tF
+Added: _$ss8UTF8SpanV17CharacterIteratorV8skipBackSiyF
+Added: _$ss8UTF8SpanV17CharacterIteratorV9codeUnitsABvg
+Added: _$ss8UTF8SpanV17CharacterIteratorVMa
+Added: _$ss8UTF8SpanV17CharacterIteratorVMn
+Added: _$ss8UTF8SpanV17CharacterIteratorVN
+Added: _$ss8UTF8SpanV17CharacterIteratorVyAdBcfC
+Added: _$ss8UTF8SpanV18_unsafeBaseAddressSVSgvM
+Added: _$ss8UTF8SpanV18_unsafeBaseAddressSVSgvg
+Added: _$ss8UTF8SpanV18_unsafeBaseAddressSVSgvs
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV11skipForward2byS2i_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV11skipForwardSiyF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV21currentCodeUnitOffsetSivg
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV4nexts0C0O0D0VSgyF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV5reset20roundingForwardsFromySi_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV5reset21roundingBackwardsFromySi_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV5reset11toUncheckedySi_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV6prefixAByF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV6suffixAByF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV8previouss0C0O0D0VSgyF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV8skipBack2byS2i_tF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV8skipBackSiyF
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorV9codeUnitsABvg
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorVMa
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorVMn
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorVN
+Added: _$ss8UTF8SpanV21UnicodeScalarIteratorVyAdBcfC
+Added: _$ss8UTF8SpanV21isCanonicallyLessThanySbABF
+Added: _$ss8UTF8SpanV21makeCharacterIteratorAB0dE0VyF
+Added: _$ss8UTF8SpanV23isCanonicallyEquivalent2toSbAB_tF
+Added: _$ss8UTF8SpanV25makeUnicodeScalarIteratorAB0deF0VyF
+Added: _$ss8UTF8SpanV4spans0B0Vys5UInt8VGvg
+Added: _$ss8UTF8SpanV7isEmptySbvg
+Added: _$ss8UTF8SpanVMa
+Added: _$ss8UTF8SpanVMn
+Added: _$ss8UTF8SpanVN
+
+
 // SE-0467 MutableSpan and MutableRawSpan
 Added: _$ss11MutableSpanVMa
 Added: _$ss11MutableSpanVMn
 Added: _$ss11MutableSpanVsRi_zrlE6_countSivg
 Added: _$ss11MutableSpanVsRi_zrlE8_pointerSvSgvg
-Added: _$ss11MutableSpanVsRi_zrlE10_uncheckedAByxGSryxG_tcfC
 Added: _$ss14MutableRawSpanV6_countSivg
 Added: _$ss14MutableRawSpanV8_pointerSvSgvg
 Added: _$ss14MutableRawSpanVMa
@@ -828,25 +926,25 @@ Added: _$ss14MutableRawSpanVMn
 Added: _$ss14MutableRawSpanVN
 
 // SE-0456 Span-providing properties
-Added: _$sSRsRi_zrlE4spans4SpanVyxGvpMV
-Added: _$sSW5bytess7RawSpanVvpMV
-Added: _$sSa4spans4SpanVyxGvpMV
-Added: _$sSrsRi_zrlE4spans4SpanVyxGvpMV
-Added: _$sSw5bytess7RawSpanVvpMV
-Added: _$ss10ArraySliceV4spans4SpanVyxGvpMV
-Added: _$ss13KeyValuePairsV4spans4SpanVyx3key_q_5valuetGvpMV
-Added: _$ss15CollectionOfOneV4spans4SpanVyxGvpMV
-Added: _$ss15ContiguousArrayV4spans4SpanVyxGvpMV
-Added: _$ss4SpanVss15BitwiseCopyableRzlE5bytess03RawA0VvpMV
 Added: _$sSS8UTF8ViewV4spans4SpanVys5UInt8VGvg
-Added: _$sSS8UTF8ViewV4spans4SpanVys5UInt8VGvpMV
 Added: _$sSs8UTF8ViewV4spans4SpanVys5UInt8VGvg
-Added: _$sSs8UTF8ViewV4spans4SpanVys5UInt8VGvpMV
 
-// SE-0467 mutableSpan properties
-Added: _$sSa11mutableSpans07MutableB0VyxGvr
-Added: _$ss10ArraySliceV11mutableSpans07MutableD0VyxGvr
-Added: _$ss15ContiguousArrayV11mutableSpans07MutableD0VyxGvr
+// OutputSpan
+Added: _$ss10OutputSpanVMa
+Added: _$ss10OutputSpanVMn
+Added: _$ss10OutputSpanVsRi_zrlE6_countSivM
+Added: _$ss10OutputSpanVsRi_zrlE6_countSivg
+Added: _$ss10OutputSpanVsRi_zrlE6_countSivs
+Added: _$ss10OutputSpanVsRi_zrlE8_pointerSvSgvg
+Added: _$ss10OutputSpanVsRi_zrlE8capacitySivg
+Added: _$ss13OutputRawSpanV6_countSivM
+Added: _$ss13OutputRawSpanV6_countSivg
+Added: _$ss13OutputRawSpanV6_countSivs
+Added: _$ss13OutputRawSpanV8_pointerSvSgvg
+Added: _$ss13OutputRawSpanV8capacitySivg
+Added: _$ss13OutputRawSpanVMa
+Added: _$ss13OutputRawSpanVMn
+Added: _$ss13OutputRawSpanVN
 
 // _SwiftifyInfo enum for _SwiftifyImports macro
 Added: _$ss13_SwiftifyExprO5paramyABSicABmFWC
@@ -887,9 +985,6 @@ Added: _$ss11InlineArrayVMa
 // InlineArray nominal type descriptor
 Added: _$ss11InlineArrayVMn
 
-// InlineArray.count property descriptor
-Added: _$ss11InlineArrayVsRi__rlE5countSivpZMV
-
 // InlineArray._storage _read accessor
 Added: _$ss11InlineArrayVsRi__rlE8_storagexq_BVvr
 
@@ -938,12 +1033,6 @@ Added: _swift_ConformanceExecutionContextSize
 Added: _swift_conformsToProtocolWithExecutionContext
 Added: _swift_isInConformanceExecutionContext
 
-// Swift Settings
-Added: _$ss12SwiftSettingVABycfC
-Added: _$ss12SwiftSettingVMa
-Added: _$ss12SwiftSettingVMn
-Added: _$ss12SwiftSettingVN
-
 // EnumeratedSequence Collection conformances
 Added: _$ss18EnumeratedSequenceVyxGSksSkRzrlMc
 Added: _$ss18EnumeratedSequenceVyxGSlsSlRzrlMc
@@ -966,3 +1055,91 @@ Added: _$ss18EnumeratedSequenceVyxGSKsSkRzrlMc
 
 // Indirect tagged string creation
 Added: __swift_stdlib_CreateIndirectTaggedPointerString
+
+// Span backward deployment
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss11MutableSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss11MutableSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss11MutableSpanVsRi_zrlE6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss11MutableSpanVsRi_zrlE8_pointerSvSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanV6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanV8_pointerSvSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss14MutableRawSpanVN$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE6_countSivM$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE6_countSivs$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE8_pointerSvSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss10OutputSpanVsRi_zrlE8capacitySivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV6_countSivM$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV6_countSivs$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV8_pointerSvSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanV8capacitySivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss13OutputRawSpanVN$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss4SpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss4SpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss4SpanVsRi_zrlE6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss4SpanVsRi_zrlE8_pointerSVSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanV6_countSivg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanV8_pointerSVSgvg$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanVMa$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanVMn$
+Added: $ld$previous$@rpath/libswiftCompatibilitySpan.dylib$$1$10.14$26.0$_$ss7RawSpanVN$
+
+// Duration.nanoseconds(_:)
+Added: _$ss8DurationV11nanosecondsyABSdFZ
+
+// var InlineArray._storage
+Added: _$ss11InlineArrayVsRi__rlE8_storagexq_BVvM
+Added: _$ss11InlineArrayVsRi__rlE8_storagexq_BVvs
+
+// rdar://151628396: Retroactively give property descriptors to conditionally-copyable/escapable properties
+Added: _$ss11InlineArrayVsRi__rlE10startIndexSivpMV
+Added: _$ss11InlineArrayVsRi__rlE5countSivpMV
+Added: _$ss11InlineArrayVsRi__rlE7_bufferSRyq_GvpMV
+Added: _$ss11InlineArrayVsRi__rlE7indicesSnySiGvpMV
+Added: _$ss11InlineArrayVsRi__rlE7isEmptySbvpMV
+Added: _$ss11InlineArrayVsRi__rlE8_addressSPyq_GvpMV
+Added: _$ss11InlineArrayVsRi__rlE8endIndexSivpMV
+Added: _$ss8UTF8SpanV10_countMasks6UInt64VvpZMV
+Added: _$ss8UTF8SpanV10_flagsMasks6UInt64VvpZMV
+Added: _$ss8UTF8SpanV7_nfcBits6UInt64VvpZMV
+Added: _$ss8UTF8SpanV9_asciiBits6UInt64VvpZMV
+
+// printing foreign reference types requires a new displayStyle: .foreign
+Added: _$ss6MirrorV12DisplayStyleO16foreignReferenceyA2DmFWC
+
+// var InlineArray._protectedBuffer
+// var InlineArray._protectedAddress
+Added: _$ss11InlineArrayVsRi__rlE16_protectedBufferSRyq_GvpMV
+Added: _$ss11InlineArrayVsRi__rlE17_protectedAddressSPyq_GvpMV
+
+// lengthOfBytes(using:)
+Added: __swift_stdlib_NSStringLengthOfBytesInEncodingTrampoline
+
+// Word breaking symbols exposed in 6.3
+Added: _$sSS10_wordIndex19somewhereAtOrBeforeSS0B0VAD_tF
+Added: _$ss7UnicodeO15_WordRecognizerV22hasCandidateBreakAtEndSbyF
+Added: _$ss7UnicodeO15_WordRecognizerV5afterAdB6ScalarV_tcfC
+Added: _$ss7UnicodeO15_WordRecognizerV8hasBreak6beforeSb12setCandidate_Sb07breakAtH0Sb0I4HeretAB6ScalarV_tF
+Added: _$ss7UnicodeO15_WordRecognizerVADycfC
+Added: _$ss7UnicodeO15_WordRecognizerVMa
+Added: _$ss7UnicodeO15_WordRecognizerVMn
+Added: _$ss7UnicodeO15_WordRecognizerVN
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerV18hasGuaranteedBreak5afterSb12setCandidate_Sb07breakAtK0Sb0L4HeretAB6ScalarV_tF
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerV6beforeAdB6ScalarV_tcfC
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerVMa
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerVMn
+Added: _$ss7UnicodeO27_RandomAccessWordRecognizerVN
+// Obsolete/broken SPIs removed in 6.3
+Removed: _$sSS17_nearestWordIndex9atOrBelowSS0C0VAD_tF
+Removed: _$sSS10_wordIndex6beforeSS0B0VAD_tF
+
+// Internal info exposed for swift-inspect.
+Added: __swift_debug_allocationPoolSize
+Added: __swift_debug_metadataAllocatorPageSize
diff --git a/test/api-digester/Inputs/stability-stdlib-abi-without-asserts-arm64.txt b/test/api-digester/Inputs/stability-stdlib-abi-without-asserts-arm64.txt
index cd107bf22ca98..38664f1fe1785 100644
--- a/test/api-digester/Inputs/stability-stdlib-abi-without-asserts-arm64.txt
+++ b/test/api-digester/Inputs/stability-stdlib-abi-without-asserts-arm64.txt
@@ -60,10 +60,10 @@ Constructor UInt8.init(exactly:) has mangled name changing from 'Swift.UInt8.ini
 Constructor UInt8.init(exactly:) has parameter 0 type change from Swift.Float80 to Swift.Float16
 Constructor _ExpressibleByBuiltinFloatLiteral.init(_builtinFloatLiteral:) has mangled name changing from 'Swift._ExpressibleByBuiltinFloatLiteral.init(_builtinFloatLiteral: Builtin.FPIEEE80) -> A' to 'Swift._ExpressibleByBuiltinFloatLiteral.init(_builtinFloatLiteral: Builtin.FPIEEE64) -> A'
 Constructor _ExpressibleByBuiltinFloatLiteral.init(_builtinFloatLiteral:) has parameter 0 type change from Builtin.FPIEEE80 to Builtin.FPIEEE64
-Func __VaListBuilder.allocStorage(wordCount:) is a new API without @available attribute
-Func __VaListBuilder.appendWords(_:) is a new API without @available attribute
-Func __VaListBuilder.deallocStorage(wordCount:storage:) is a new API without @available attribute
-Func __VaListBuilder.rawSizeAndAlignment(_:) is a new API without @available attribute
+Func __VaListBuilder.allocStorage(wordCount:) is a new API without '@available'
+Func __VaListBuilder.appendWords(_:) is a new API without '@available'
+Func __VaListBuilder.deallocStorage(wordCount:storage:) is a new API without '@available'
+Func __VaListBuilder.rawSizeAndAlignment(_:) is a new API without '@available'
 Func _cos(_:) has been removed
 Func _exp(_:) has been removed
 Func _exp2(_:) has been removed
@@ -75,14 +75,14 @@ Func _rint(_:) has been removed
 Func _sin(_:) has been removed
 Struct Float80 has been removed
 Struct __VaListBuilder.Header has been removed
-Var __VaListBuilder.allocated is a new API without @available attribute
+Var __VaListBuilder.allocated is a new API without '@available'
 Var __VaListBuilder.allocated is added to a non-resilient type
-Var __VaListBuilder.count is a new API without @available attribute
+Var __VaListBuilder.count is a new API without '@available'
 Var __VaListBuilder.count is added to a non-resilient type
 Var __VaListBuilder.fpRegistersUsed has been removed
 Var __VaListBuilder.gpRegistersUsed has been removed
 Var __VaListBuilder.header has been removed
-Var __VaListBuilder.requiredAlignmentInBytes is a new API without @available attribute
+Var __VaListBuilder.requiredAlignmentInBytes is a new API without '@available'
 Var __VaListBuilder.requiredAlignmentInBytes is added to a non-resilient type
 Var __VaListBuilder.storage has declared type change from Swift.ContiguousArray<Swift.Int> to Swift.UnsafeMutablePointer<Swift.Int>?
 Var __VaListBuilder.storage has mangled name changing from 'Swift.__VaListBuilder.storage : Swift.ContiguousArray<Swift.Int>' to 'Swift.__VaListBuilder.storage : Swift.Optional<Swift.UnsafeMutablePointer<Swift.Int>>'
diff --git a/test/api-digester/Outputs/Cake-abi.txt b/test/api-digester/Outputs/Cake-abi.txt
index bc537b38352ea..a01724e5fbf2b 100644
--- a/test/api-digester/Outputs/Cake-abi.txt
+++ b/test/api-digester/Outputs/Cake-abi.txt
@@ -49,8 +49,8 @@ cake: Constructor S1.init(_:) has parameter 0 type change from Swift.Int to Swif
 cake: Func C1.foo2(_:) has parameter 0 type change from Swift.Int to () -> ()
 cake: Func C7.foo(_:_:) has removed default argument from parameter 0
 cake: Func C7.foo(_:_:) has removed default argument from parameter 1
-cake: Func EscapingFunctionType.addedEscaping(_:) has added @escaping in parameter 0
-cake: Func EscapingFunctionType.removedEscaping(_:) has removed @escaping in parameter 0
+cake: Func EscapingFunctionType.addedEscaping(_:) has added '@escaping' in parameter 0
+cake: Func EscapingFunctionType.removedEscaping(_:) has removed '@escaping' in parameter 0
 cake: Func Somestruct2.foo1(_:) has parameter 0 type change from cake.C3 to cake.C1
 cake: Func Zoo.getCurrentAnimalInlinable() has return type change from [cake.Cat] to [cake.Dog]
 cake: Func ownershipChange(_:_:) has parameter 0 changing from InOut to Default
@@ -59,41 +59,41 @@ cake: Func returnFunctionTypeOwnershipChange() has return type change from (cake
 cake: Var Zoo.current has declared type change from cake.Cat to cake.Dog
 
 /* Decl Attribute changes */
-cake: Accessor GlobalLetChangedToVar.Modify() is a new API without @available attribute
-cake: Accessor GlobalLetChangedToVar.Set() is a new API without @available attribute
-cake: Accessor fixedLayoutStruct2.BecomeFixedBinaryOrder.Modify() is a new API without @available attribute
-cake: Accessor fixedLayoutStruct2.BecomeFixedBinaryOrder.Set() is a new API without @available attribute
-cake: AssociatedType RequirementChanges.addedTypeWithDefault is a new API without @available attribute
-cake: AssociatedType RequirementChanges.addedTypeWithoutDefault is a new API without @available attribute
-cake: Class C0 is a new API without @available attribute
-cake: Class C8 is a new API without @available attribute
-cake: Constructor AddingNewDesignatedInit.init(_:) is a new API without @available attribute
-cake: Constructor C1.init(_:) is a new API without @available attribute
-cake: Constructor ClassWithMissingDesignatedInits.init() is a new API without @available attribute
-cake: Constructor SubclassWithMissingDesignatedInits.init() is a new API without @available attribute
+cake: Accessor GlobalLetChangedToVar.Modify() is a new API without '@available'
+cake: Accessor GlobalLetChangedToVar.Set() is a new API without '@available'
+cake: Accessor fixedLayoutStruct2.BecomeFixedBinaryOrder.Modify() is a new API without '@available'
+cake: Accessor fixedLayoutStruct2.BecomeFixedBinaryOrder.Set() is a new API without '@available'
+cake: AssociatedType RequirementChanges.addedTypeWithDefault is a new API without '@available'
+cake: AssociatedType RequirementChanges.addedTypeWithoutDefault is a new API without '@available'
+cake: Class C0 is a new API without '@available'
+cake: Class C8 is a new API without '@available'
+cake: Constructor AddingNewDesignatedInit.init(_:) is a new API without '@available'
+cake: Constructor C1.init(_:) is a new API without '@available'
+cake: Constructor ClassWithMissingDesignatedInits.init() is a new API without '@available'
+cake: Constructor SubclassWithMissingDesignatedInits.init() is a new API without '@available'
 cake: Enum IceKind is now without @frozen
-cake: EnumElement FrozenKind.AddedCase is a new API without @available attribute
-cake: EnumElement FutureKind.FineToAdd is a new API without @available attribute
+cake: EnumElement FrozenKind.AddedCase is a new API without '@available'
+cake: EnumElement FutureKind.FineToAdd is a new API without '@available'
 cake: Func C1.foo1() is now not static
 cake: Func FinalFuncContainer.NewFinalFunc() is now with final
 cake: Func FinalFuncContainer.NoLongerFinalFunc() is now without final
-cake: Func Float.floatHigher() is a new API without @available attribute
-cake: Func FutureKind.==(_:_:) is a new API without @available attribute
-cake: Func FutureKind.hash(into:) is a new API without @available attribute
+cake: Func Float.floatHigher() is a new API without '@available'
+cake: Func FutureKind.==(_:_:) is a new API without '@available'
+cake: Func FutureKind.hash(into:) is a new API without '@available'
 cake: Func HasMutatingMethodClone.foo() has self access kind changing from Mutating to NonMutating
-cake: Func RequirementChanges.addedFunc() is a new API without @available attribute
+cake: Func RequirementChanges.addedFunc() is a new API without '@available'
 cake: Func S1.foo1() has self access kind changing from NonMutating to Mutating
 cake: Func S1.foo3() is now static
 cake: Func _NoResilientClass.NoLongerFinalFunc() is now without final
-cake: Func fixedLayoutStruct.OKChange() is a new API without @available attribute
-cake: Protocol P4 is a new API without @available attribute
+cake: Func fixedLayoutStruct.OKChange() is a new API without '@available'
+cake: Protocol P4 is a new API without '@available'
 cake: Struct C6 is now with @frozen
 cake: Var C1.CIIns1 changes from weak to strong
 cake: Var C1.CIIns2 changes from strong to weak
-cake: Var FutureKind.hashValue is a new API without @available attribute
-cake: Var RequirementChanges.addedVar is a new API without @available attribute
-cake: Var fixedLayoutStruct.$__lazy_storage_$_lazy_d is a new API without @available attribute
-cake: Var fixedLayoutStruct.c is a new API without @available attribute
+cake: Var FutureKind.hashValue is a new API without '@available'
+cake: Var RequirementChanges.addedVar is a new API without '@available'
+cake: Var fixedLayoutStruct.$__lazy_storage_$_lazy_d is a new API without '@available'
+cake: Var fixedLayoutStruct.c is a new API without '@available'
 
 /* Fixed-layout Type Changes */
 cake: EnumElement FrozenKind.AddedCase is added to a non-resilient type
diff --git a/test/api-digester/Outputs/Cake-binary-vs-interface.txt b/test/api-digester/Outputs/Cake-binary-vs-interface.txt
index a4653d5a8dc32..5ffc0a3e9e90d 100644
--- a/test/api-digester/Outputs/Cake-binary-vs-interface.txt
+++ b/test/api-digester/Outputs/Cake-binary-vs-interface.txt
@@ -1,9 +1,9 @@
 cake: Func FrozenKind.__derived_enum_equals(_:_:) has been removed
-cake: Accessor GlobalLetChangedToVar.Get() is a new API without @available attribute
-cake: Accessor GlobalVarChangedToLet.Get() is a new API without @available attribute
-cake: Accessor GlobalVarChangedToLet.Modify() is a new API without @available attribute
-cake: Accessor GlobalVarChangedToLet.Set() is a new API without @available attribute
-cake: Func FrozenKind.==(_:_:) is a new API without @available attribute
+cake: Accessor GlobalLetChangedToVar.Get() is a new API without '@available'
+cake: Accessor GlobalVarChangedToLet.Get() is a new API without '@available'
+cake: Accessor GlobalVarChangedToLet.Modify() is a new API without '@available'
+cake: Accessor GlobalVarChangedToLet.Set() is a new API without '@available'
+cake: Func FrozenKind.==(_:_:) is a new API without '@available'
 cake: Var C1.CIIns1 is no longer a stored property
 cake: Var C1.CIIns2 is no longer a stored property
 cake: Var RemoveSetters.Value is no longer a stored property
diff --git a/test/api-digester/Outputs/color_vs_empty.txt b/test/api-digester/Outputs/color_vs_empty.txt
index 5ffa53874c59b..e2d3cfc3ce01c 100644
--- a/test/api-digester/Outputs/color_vs_empty.txt
+++ b/test/api-digester/Outputs/color_vs_empty.txt
@@ -1 +1 @@
-Enum Color is a new API without @available attribute
+Enum Color is a new API without '@available'
diff --git a/test/api-digester/Outputs/cake-abi.json b/test/api-digester/Outputs/dump-module/cake-abi.json
similarity index 100%
rename from test/api-digester/Outputs/cake-abi.json
rename to test/api-digester/Outputs/dump-module/cake-abi.json
index a1697144c7a31..3dc45f9312fce 100644
--- a/test/api-digester/Outputs/cake-abi.json
+++ b/test/api-digester/Outputs/dump-module/cake-abi.json
@@ -232,20 +232,6 @@
           "Frozen"
         ],
         "conformances": [
-          {
-            "kind": "Conformance",
-            "name": "P1",
-            "printedName": "P1",
-            "usr": "s:4cake2P1P",
-            "mangledName": "$s4cake2P1P"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Sendable",
-            "printedName": "Sendable",
-            "usr": "s:s8SendableP",
-            "mangledName": "$ss8SendableP"
-          },
           {
             "kind": "Conformance",
             "name": "BitwiseCopyable",
@@ -267,6 +253,13 @@
             "usr": "s:s9EscapableP",
             "mangledName": "$ss9EscapableP"
           },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
           {
             "kind": "Conformance",
             "name": "SendableMetatype",
@@ -274,6 +267,13 @@
             "usr": "s:s16SendableMetatypeP",
             "mangledName": "$ss16SendableMetatypeP"
           },
+          {
+            "kind": "Conformance",
+            "name": "P1",
+            "printedName": "P1",
+            "usr": "s:4cake2P1P",
+            "mangledName": "$s4cake2P1P"
+          },
           {
             "kind": "Conformance",
             "name": "P2",
@@ -801,6 +801,13 @@
         "enumRawTypeName": "Int",
         "isEnumExhaustive": true,
         "conformances": [
+          {
+            "kind": "Conformance",
+            "name": "Copyable",
+            "printedName": "Copyable",
+            "usr": "s:s8CopyableP",
+            "mangledName": "$ss8CopyableP"
+          },
           {
             "kind": "Conformance",
             "name": "Equatable",
@@ -808,6 +815,13 @@
             "usr": "s:SQ",
             "mangledName": "$sSQ"
           },
+          {
+            "kind": "Conformance",
+            "name": "Escapable",
+            "printedName": "Escapable",
+            "usr": "s:s9EscapableP",
+            "mangledName": "$ss9EscapableP"
+          },
           {
             "kind": "Conformance",
             "name": "Hashable",
@@ -836,20 +850,6 @@
             ],
             "usr": "s:SY",
             "mangledName": "$sSY"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Copyable",
-            "printedName": "Copyable",
-            "usr": "s:s8CopyableP",
-            "mangledName": "$ss8CopyableP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Escapable",
-            "printedName": "Escapable",
-            "usr": "s:s9EscapableP",
-            "mangledName": "$ss9EscapableP"
           }
         ]
       },
@@ -1047,13 +1047,6 @@
           "Frozen"
         ],
         "conformances": [
-          {
-            "kind": "Conformance",
-            "name": "Sendable",
-            "printedName": "Sendable",
-            "usr": "s:s8SendableP",
-            "mangledName": "$ss8SendableP"
-          },
           {
             "kind": "Conformance",
             "name": "BitwiseCopyable",
@@ -1075,6 +1068,13 @@
             "usr": "s:s9EscapableP",
             "mangledName": "$ss9EscapableP"
           },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
           {
             "kind": "Conformance",
             "name": "SendableMetatype",
@@ -1998,24 +1998,10 @@
         "conformances": [
           {
             "kind": "Conformance",
-            "name": "FixedWidthInteger",
-            "printedName": "FixedWidthInteger",
-            "usr": "s:s17FixedWidthIntegerP",
-            "mangledName": "$ss17FixedWidthIntegerP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "SignedInteger",
-            "printedName": "SignedInteger",
-            "usr": "s:SZ",
-            "mangledName": "$sSZ"
-          },
-          {
-            "kind": "Conformance",
-            "name": "_ExpressibleByBuiltinIntegerLiteral",
-            "printedName": "_ExpressibleByBuiltinIntegerLiteral",
-            "usr": "s:s35_ExpressibleByBuiltinIntegerLiteralP",
-            "mangledName": "$ss35_ExpressibleByBuiltinIntegerLiteralP"
+            "name": "AdditiveArithmetic",
+            "printedName": "AdditiveArithmetic",
+            "usr": "s:s18AdditiveArithmeticP",
+            "mangledName": "$ss18AdditiveArithmeticP"
           },
           {
             "kind": "Conformance",
@@ -2041,97 +2027,24 @@
           },
           {
             "kind": "Conformance",
-            "name": "LosslessStringConvertible",
-            "printedName": "LosslessStringConvertible",
-            "usr": "s:s25LosslessStringConvertibleP",
-            "mangledName": "$ss25LosslessStringConvertibleP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "SignedNumeric",
-            "printedName": "SignedNumeric",
-            "usr": "s:s13SignedNumericP",
-            "mangledName": "$ss13SignedNumericP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Numeric",
-            "printedName": "Numeric",
-            "children": [
-              {
-                "kind": "TypeWitness",
-                "name": "Magnitude",
-                "printedName": "Magnitude",
-                "children": [
-                  {
-                    "kind": "TypeNominal",
-                    "name": "UInt",
-                    "printedName": "Swift.UInt",
-                    "usr": "s:Su"
-                  }
-                ]
-              }
-            ],
-            "usr": "s:Sj",
-            "mangledName": "$sSj"
-          },
-          {
-            "kind": "Conformance",
-            "name": "CustomStringConvertible",
-            "printedName": "CustomStringConvertible",
-            "usr": "s:s23CustomStringConvertibleP",
-            "mangledName": "$ss23CustomStringConvertibleP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Strideable",
-            "printedName": "Strideable",
-            "children": [
-              {
-                "kind": "TypeWitness",
-                "name": "Stride",
-                "printedName": "Stride",
-                "children": [
-                  {
-                    "kind": "TypeNominal",
-                    "name": "Int",
-                    "printedName": "Swift.Int",
-                    "usr": "s:Si"
-                  }
-                ]
-              }
-            ],
-            "usr": "s:Sx",
-            "mangledName": "$sSx"
+            "name": "BitwiseCopyable",
+            "printedName": "BitwiseCopyable",
+            "usr": "s:s15BitwiseCopyableP",
+            "mangledName": "$ss15BitwiseCopyableP"
           },
           {
             "kind": "Conformance",
-            "name": "AdditiveArithmetic",
-            "printedName": "AdditiveArithmetic",
-            "usr": "s:s18AdditiveArithmeticP",
-            "mangledName": "$ss18AdditiveArithmeticP"
+            "name": "CVarArg",
+            "printedName": "CVarArg",
+            "usr": "s:s7CVarArgP",
+            "mangledName": "$ss7CVarArgP"
           },
           {
             "kind": "Conformance",
-            "name": "ExpressibleByIntegerLiteral",
-            "printedName": "ExpressibleByIntegerLiteral",
-            "children": [
-              {
-                "kind": "TypeWitness",
-                "name": "IntegerLiteralType",
-                "printedName": "IntegerLiteralType",
-                "children": [
-                  {
-                    "kind": "TypeNominal",
-                    "name": "Int",
-                    "printedName": "Swift.Int",
-                    "usr": "s:Si"
-                  }
-                ]
-              }
-            ],
-            "usr": "s:s27ExpressibleByIntegerLiteralP",
-            "mangledName": "$ss27ExpressibleByIntegerLiteralP"
+            "name": "CodingKeyRepresentable",
+            "printedName": "CodingKeyRepresentable",
+            "usr": "s:s22CodingKeyRepresentableP",
+            "mangledName": "$ss22CodingKeyRepresentableP"
           },
           {
             "kind": "Conformance",
@@ -2149,24 +2062,17 @@
           },
           {
             "kind": "Conformance",
-            "name": "Escapable",
-            "printedName": "Escapable",
-            "usr": "s:s9EscapableP",
-            "mangledName": "$ss9EscapableP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "P1",
-            "printedName": "P1",
-            "usr": "s:4cake2P1P",
-            "mangledName": "$s4cake2P1P"
+            "name": "CustomReflectable",
+            "printedName": "CustomReflectable",
+            "usr": "s:s17CustomReflectableP",
+            "mangledName": "$ss17CustomReflectableP"
           },
           {
             "kind": "Conformance",
-            "name": "Encodable",
-            "printedName": "Encodable",
-            "usr": "s:SE",
-            "mangledName": "$sSE"
+            "name": "CustomStringConvertible",
+            "printedName": "CustomStringConvertible",
+            "usr": "s:s23CustomStringConvertibleP",
+            "mangledName": "$ss23CustomStringConvertibleP"
           },
           {
             "kind": "Conformance",
@@ -2177,38 +2083,53 @@
           },
           {
             "kind": "Conformance",
-            "name": "CodingKeyRepresentable",
-            "printedName": "CodingKeyRepresentable",
-            "usr": "s:s22CodingKeyRepresentableP",
-            "mangledName": "$ss22CodingKeyRepresentableP"
+            "name": "Encodable",
+            "printedName": "Encodable",
+            "usr": "s:SE",
+            "mangledName": "$sSE"
           },
           {
             "kind": "Conformance",
-            "name": "CustomReflectable",
-            "printedName": "CustomReflectable",
-            "usr": "s:s17CustomReflectableP",
-            "mangledName": "$ss17CustomReflectableP"
+            "name": "Equatable",
+            "printedName": "Equatable",
+            "usr": "s:SQ",
+            "mangledName": "$sSQ"
           },
           {
             "kind": "Conformance",
-            "name": "_CustomPlaygroundQuickLookable",
-            "printedName": "_CustomPlaygroundQuickLookable",
-            "usr": "s:s30_CustomPlaygroundQuickLookableP",
-            "mangledName": "$ss30_CustomPlaygroundQuickLookableP"
+            "name": "Escapable",
+            "printedName": "Escapable",
+            "usr": "s:s9EscapableP",
+            "mangledName": "$ss9EscapableP"
           },
           {
             "kind": "Conformance",
-            "name": "MirrorPath",
-            "printedName": "MirrorPath",
-            "usr": "s:s10MirrorPathP",
-            "mangledName": "$ss10MirrorPathP"
+            "name": "ExpressibleByIntegerLiteral",
+            "printedName": "ExpressibleByIntegerLiteral",
+            "children": [
+              {
+                "kind": "TypeWitness",
+                "name": "IntegerLiteralType",
+                "printedName": "IntegerLiteralType",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Int",
+                    "printedName": "Swift.Int",
+                    "usr": "s:Si"
+                  }
+                ]
+              }
+            ],
+            "usr": "s:s27ExpressibleByIntegerLiteralP",
+            "mangledName": "$ss27ExpressibleByIntegerLiteralP"
           },
           {
             "kind": "Conformance",
-            "name": "CVarArg",
-            "printedName": "CVarArg",
-            "usr": "s:s7CVarArgP",
-            "mangledName": "$ss7CVarArgP"
+            "name": "FixedWidthInteger",
+            "printedName": "FixedWidthInteger",
+            "usr": "s:s17FixedWidthIntegerP",
+            "mangledName": "$ss17FixedWidthIntegerP"
           },
           {
             "kind": "Conformance",
@@ -2219,31 +2140,39 @@
           },
           {
             "kind": "Conformance",
-            "name": "Equatable",
-            "printedName": "Equatable",
-            "usr": "s:SQ",
-            "mangledName": "$sSQ"
-          },
-          {
-            "kind": "Conformance",
-            "name": "_HasCustomAnyHashableRepresentation",
-            "printedName": "_HasCustomAnyHashableRepresentation",
-            "usr": "s:s35_HasCustomAnyHashableRepresentationP",
-            "mangledName": "$ss35_HasCustomAnyHashableRepresentationP"
+            "name": "LosslessStringConvertible",
+            "printedName": "LosslessStringConvertible",
+            "usr": "s:s25LosslessStringConvertibleP",
+            "mangledName": "$ss25LosslessStringConvertibleP"
           },
           {
             "kind": "Conformance",
-            "name": "Sendable",
-            "printedName": "Sendable",
-            "usr": "s:s8SendableP",
-            "mangledName": "$ss8SendableP"
+            "name": "MirrorPath",
+            "printedName": "MirrorPath",
+            "usr": "s:s10MirrorPathP",
+            "mangledName": "$ss10MirrorPathP"
           },
           {
             "kind": "Conformance",
-            "name": "SendableMetatype",
-            "printedName": "SendableMetatype",
-            "usr": "s:s16SendableMetatypeP",
-            "mangledName": "$ss16SendableMetatypeP"
+            "name": "Numeric",
+            "printedName": "Numeric",
+            "children": [
+              {
+                "kind": "TypeWitness",
+                "name": "Magnitude",
+                "printedName": "Magnitude",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "UInt",
+                    "printedName": "Swift.UInt",
+                    "usr": "s:Su"
+                  }
+                ]
+              }
+            ],
+            "usr": "s:Sj",
+            "mangledName": "$sSj"
           },
           {
             "kind": "Conformance",
@@ -2347,10 +2276,81 @@
           },
           {
             "kind": "Conformance",
-            "name": "BitwiseCopyable",
-            "printedName": "BitwiseCopyable",
-            "usr": "s:s15BitwiseCopyableP",
-            "mangledName": "$ss15BitwiseCopyableP"
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SignedInteger",
+            "printedName": "SignedInteger",
+            "usr": "s:SZ",
+            "mangledName": "$sSZ"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SignedNumeric",
+            "printedName": "SignedNumeric",
+            "usr": "s:s13SignedNumericP",
+            "mangledName": "$ss13SignedNumericP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "Strideable",
+            "printedName": "Strideable",
+            "children": [
+              {
+                "kind": "TypeWitness",
+                "name": "Stride",
+                "printedName": "Stride",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Int",
+                    "printedName": "Swift.Int",
+                    "usr": "s:Si"
+                  }
+                ]
+              }
+            ],
+            "usr": "s:Sx",
+            "mangledName": "$sSx"
+          },
+          {
+            "kind": "Conformance",
+            "name": "_CustomPlaygroundQuickLookable",
+            "printedName": "_CustomPlaygroundQuickLookable",
+            "usr": "s:s30_CustomPlaygroundQuickLookableP",
+            "mangledName": "$ss30_CustomPlaygroundQuickLookableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "_ExpressibleByBuiltinIntegerLiteral",
+            "printedName": "_ExpressibleByBuiltinIntegerLiteral",
+            "usr": "s:s35_ExpressibleByBuiltinIntegerLiteralP",
+            "mangledName": "$ss35_ExpressibleByBuiltinIntegerLiteralP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "_HasCustomAnyHashableRepresentation",
+            "printedName": "_HasCustomAnyHashableRepresentation",
+            "usr": "s:s35_HasCustomAnyHashableRepresentationP",
+            "mangledName": "$ss35_HasCustomAnyHashableRepresentationP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "P1",
+            "printedName": "P1",
+            "usr": "s:4cake2P1P",
+            "mangledName": "$s4cake2P1P"
           }
         ]
       }
diff --git a/test/api-digester/Outputs/cake.json b/test/api-digester/Outputs/dump-module/cake.json
similarity index 100%
rename from test/api-digester/Outputs/cake.json
rename to test/api-digester/Outputs/dump-module/cake.json
index 5f1d958671cea..ddd11114a05fd 100644
--- a/test/api-digester/Outputs/cake.json
+++ b/test/api-digester/Outputs/dump-module/cake.json
@@ -237,20 +237,6 @@
           "Frozen"
         ],
         "conformances": [
-          {
-            "kind": "Conformance",
-            "name": "P1",
-            "printedName": "P1",
-            "usr": "s:4cake2P1P",
-            "mangledName": "$s4cake2P1P"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Sendable",
-            "printedName": "Sendable",
-            "usr": "s:s8SendableP",
-            "mangledName": "$ss8SendableP"
-          },
           {
             "kind": "Conformance",
             "name": "BitwiseCopyable",
@@ -272,6 +258,13 @@
             "usr": "s:s9EscapableP",
             "mangledName": "$ss9EscapableP"
           },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
           {
             "kind": "Conformance",
             "name": "SendableMetatype",
@@ -279,6 +272,13 @@
             "usr": "s:s16SendableMetatypeP",
             "mangledName": "$ss16SendableMetatypeP"
           },
+          {
+            "kind": "Conformance",
+            "name": "P1",
+            "printedName": "P1",
+            "usr": "s:4cake2P1P",
+            "mangledName": "$s4cake2P1P"
+          },
           {
             "kind": "Conformance",
             "name": "P2",
@@ -814,6 +814,13 @@
         "enumRawTypeName": "Int",
         "isEnumExhaustive": true,
         "conformances": [
+          {
+            "kind": "Conformance",
+            "name": "Copyable",
+            "printedName": "Copyable",
+            "usr": "s:s8CopyableP",
+            "mangledName": "$ss8CopyableP"
+          },
           {
             "kind": "Conformance",
             "name": "Equatable",
@@ -821,6 +828,13 @@
             "usr": "s:SQ",
             "mangledName": "$sSQ"
           },
+          {
+            "kind": "Conformance",
+            "name": "Escapable",
+            "printedName": "Escapable",
+            "usr": "s:s9EscapableP",
+            "mangledName": "$ss9EscapableP"
+          },
           {
             "kind": "Conformance",
             "name": "Hashable",
@@ -849,20 +863,6 @@
             ],
             "usr": "s:SY",
             "mangledName": "$sSY"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Copyable",
-            "printedName": "Copyable",
-            "usr": "s:s8CopyableP",
-            "mangledName": "$ss8CopyableP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Escapable",
-            "printedName": "Escapable",
-            "usr": "s:s9EscapableP",
-            "mangledName": "$ss9EscapableP"
           }
         ]
       },
@@ -990,13 +990,6 @@
           "Frozen"
         ],
         "conformances": [
-          {
-            "kind": "Conformance",
-            "name": "Sendable",
-            "printedName": "Sendable",
-            "usr": "s:s8SendableP",
-            "mangledName": "$ss8SendableP"
-          },
           {
             "kind": "Conformance",
             "name": "BitwiseCopyable",
@@ -1018,6 +1011,13 @@
             "usr": "s:s9EscapableP",
             "mangledName": "$ss9EscapableP"
           },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
           {
             "kind": "Conformance",
             "name": "SendableMetatype",
@@ -1885,17 +1885,10 @@
         "conformances": [
           {
             "kind": "Conformance",
-            "name": "FixedWidthInteger",
-            "printedName": "FixedWidthInteger",
-            "usr": "s:s17FixedWidthIntegerP",
-            "mangledName": "$ss17FixedWidthIntegerP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "SignedInteger",
-            "printedName": "SignedInteger",
-            "usr": "s:SZ",
-            "mangledName": "$sSZ"
+            "name": "AdditiveArithmetic",
+            "printedName": "AdditiveArithmetic",
+            "usr": "s:s18AdditiveArithmeticP",
+            "mangledName": "$ss18AdditiveArithmeticP"
           },
           {
             "kind": "Conformance",
@@ -1921,46 +1914,45 @@
           },
           {
             "kind": "Conformance",
-            "name": "LosslessStringConvertible",
-            "printedName": "LosslessStringConvertible",
-            "usr": "s:s25LosslessStringConvertibleP",
-            "mangledName": "$ss25LosslessStringConvertibleP"
+            "name": "BitwiseCopyable",
+            "printedName": "BitwiseCopyable",
+            "usr": "s:s15BitwiseCopyableP",
+            "mangledName": "$ss15BitwiseCopyableP"
           },
           {
             "kind": "Conformance",
-            "name": "SignedNumeric",
-            "printedName": "SignedNumeric",
-            "usr": "s:s13SignedNumericP",
-            "mangledName": "$ss13SignedNumericP"
+            "name": "CVarArg",
+            "printedName": "CVarArg",
+            "usr": "s:s7CVarArgP",
+            "mangledName": "$ss7CVarArgP"
           },
           {
             "kind": "Conformance",
-            "name": "Numeric",
-            "printedName": "Numeric",
-            "children": [
-              {
-                "kind": "TypeWitness",
-                "name": "Magnitude",
-                "printedName": "Magnitude",
-                "children": [
-                  {
-                    "kind": "TypeNameAlias",
-                    "name": "Magnitude",
-                    "printedName": "Swift.Int.Magnitude",
-                    "children": [
-                      {
-                        "kind": "TypeNominal",
-                        "name": "UInt",
-                        "printedName": "Swift.UInt",
-                        "usr": "s:Su"
-                      }
-                    ]
-                  }
-                ]
-              }
-            ],
-            "usr": "s:Sj",
-            "mangledName": "$sSj"
+            "name": "CodingKeyRepresentable",
+            "printedName": "CodingKeyRepresentable",
+            "usr": "s:s22CodingKeyRepresentableP",
+            "mangledName": "$ss22CodingKeyRepresentableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "Comparable",
+            "printedName": "Comparable",
+            "usr": "s:SL",
+            "mangledName": "$sSL"
+          },
+          {
+            "kind": "Conformance",
+            "name": "Copyable",
+            "printedName": "Copyable",
+            "usr": "s:s8CopyableP",
+            "mangledName": "$ss8CopyableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "CustomReflectable",
+            "printedName": "CustomReflectable",
+            "usr": "s:s17CustomReflectableP",
+            "mangledName": "$ss17CustomReflectableP"
           },
           {
             "kind": "Conformance",
@@ -1971,32 +1963,31 @@
           },
           {
             "kind": "Conformance",
-            "name": "Strideable",
-            "printedName": "Strideable",
-            "children": [
-              {
-                "kind": "TypeWitness",
-                "name": "Stride",
-                "printedName": "Stride",
-                "children": [
-                  {
-                    "kind": "TypeNominal",
-                    "name": "Int",
-                    "printedName": "Swift.Int",
-                    "usr": "s:Si"
-                  }
-                ]
-              }
-            ],
-            "usr": "s:Sx",
-            "mangledName": "$sSx"
+            "name": "Decodable",
+            "printedName": "Decodable",
+            "usr": "s:Se",
+            "mangledName": "$sSe"
           },
           {
             "kind": "Conformance",
-            "name": "AdditiveArithmetic",
-            "printedName": "AdditiveArithmetic",
-            "usr": "s:s18AdditiveArithmeticP",
-            "mangledName": "$ss18AdditiveArithmeticP"
+            "name": "Encodable",
+            "printedName": "Encodable",
+            "usr": "s:SE",
+            "mangledName": "$sSE"
+          },
+          {
+            "kind": "Conformance",
+            "name": "Equatable",
+            "printedName": "Equatable",
+            "usr": "s:SQ",
+            "mangledName": "$sSQ"
+          },
+          {
+            "kind": "Conformance",
+            "name": "Escapable",
+            "printedName": "Escapable",
+            "usr": "s:s9EscapableP",
+            "mangledName": "$ss9EscapableP"
           },
           {
             "kind": "Conformance",
@@ -2029,73 +2020,10 @@
           },
           {
             "kind": "Conformance",
-            "name": "Comparable",
-            "printedName": "Comparable",
-            "usr": "s:SL",
-            "mangledName": "$sSL"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Copyable",
-            "printedName": "Copyable",
-            "usr": "s:s8CopyableP",
-            "mangledName": "$ss8CopyableP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Escapable",
-            "printedName": "Escapable",
-            "usr": "s:s9EscapableP",
-            "mangledName": "$ss9EscapableP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "P1",
-            "printedName": "P1",
-            "usr": "s:4cake2P1P",
-            "mangledName": "$s4cake2P1P"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Encodable",
-            "printedName": "Encodable",
-            "usr": "s:SE",
-            "mangledName": "$sSE"
-          },
-          {
-            "kind": "Conformance",
-            "name": "Decodable",
-            "printedName": "Decodable",
-            "usr": "s:Se",
-            "mangledName": "$sSe"
-          },
-          {
-            "kind": "Conformance",
-            "name": "CodingKeyRepresentable",
-            "printedName": "CodingKeyRepresentable",
-            "usr": "s:s22CodingKeyRepresentableP",
-            "mangledName": "$ss22CodingKeyRepresentableP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "CustomReflectable",
-            "printedName": "CustomReflectable",
-            "usr": "s:s17CustomReflectableP",
-            "mangledName": "$ss17CustomReflectableP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "MirrorPath",
-            "printedName": "MirrorPath",
-            "usr": "s:s10MirrorPathP",
-            "mangledName": "$ss10MirrorPathP"
-          },
-          {
-            "kind": "Conformance",
-            "name": "CVarArg",
-            "printedName": "CVarArg",
-            "usr": "s:s7CVarArgP",
-            "mangledName": "$ss7CVarArgP"
+            "name": "FixedWidthInteger",
+            "printedName": "FixedWidthInteger",
+            "usr": "s:s17FixedWidthIntegerP",
+            "mangledName": "$ss17FixedWidthIntegerP"
           },
           {
             "kind": "Conformance",
@@ -2106,24 +2034,46 @@
           },
           {
             "kind": "Conformance",
-            "name": "Equatable",
-            "printedName": "Equatable",
-            "usr": "s:SQ",
-            "mangledName": "$sSQ"
+            "name": "LosslessStringConvertible",
+            "printedName": "LosslessStringConvertible",
+            "usr": "s:s25LosslessStringConvertibleP",
+            "mangledName": "$ss25LosslessStringConvertibleP"
           },
           {
             "kind": "Conformance",
-            "name": "Sendable",
-            "printedName": "Sendable",
-            "usr": "s:s8SendableP",
-            "mangledName": "$ss8SendableP"
+            "name": "MirrorPath",
+            "printedName": "MirrorPath",
+            "usr": "s:s10MirrorPathP",
+            "mangledName": "$ss10MirrorPathP"
           },
           {
             "kind": "Conformance",
-            "name": "SendableMetatype",
-            "printedName": "SendableMetatype",
-            "usr": "s:s16SendableMetatypeP",
-            "mangledName": "$ss16SendableMetatypeP"
+            "name": "Numeric",
+            "printedName": "Numeric",
+            "children": [
+              {
+                "kind": "TypeWitness",
+                "name": "Magnitude",
+                "printedName": "Magnitude",
+                "children": [
+                  {
+                    "kind": "TypeNameAlias",
+                    "name": "Magnitude",
+                    "printedName": "Swift.Int.Magnitude",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "UInt",
+                        "printedName": "Swift.UInt",
+                        "usr": "s:Su"
+                      }
+                    ]
+                  }
+                ]
+              }
+            ],
+            "usr": "s:Sj",
+            "mangledName": "$sSj"
           },
           {
             "kind": "Conformance",
@@ -2234,10 +2184,60 @@
           },
           {
             "kind": "Conformance",
-            "name": "BitwiseCopyable",
-            "printedName": "BitwiseCopyable",
-            "usr": "s:s15BitwiseCopyableP",
-            "mangledName": "$ss15BitwiseCopyableP"
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SignedInteger",
+            "printedName": "SignedInteger",
+            "usr": "s:SZ",
+            "mangledName": "$sSZ"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SignedNumeric",
+            "printedName": "SignedNumeric",
+            "usr": "s:s13SignedNumericP",
+            "mangledName": "$ss13SignedNumericP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "Strideable",
+            "printedName": "Strideable",
+            "children": [
+              {
+                "kind": "TypeWitness",
+                "name": "Stride",
+                "printedName": "Stride",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Int",
+                    "printedName": "Swift.Int",
+                    "usr": "s:Si"
+                  }
+                ]
+              }
+            ],
+            "usr": "s:Sx",
+            "mangledName": "$sSx"
+          },
+          {
+            "kind": "Conformance",
+            "name": "P1",
+            "printedName": "P1",
+            "usr": "s:4cake2P1P",
+            "mangledName": "$s4cake2P1P"
           }
         ]
       }
diff --git a/test/api-digester/Outputs/stability-stdlib-source-base.swift.expected b/test/api-digester/Outputs/stability-stdlib-source-base.swift.expected
index 9e3db06e13d69..4b8e01dec4137 100644
--- a/test/api-digester/Outputs/stability-stdlib-source-base.swift.expected
+++ b/test/api-digester/Outputs/stability-stdlib-source-base.swift.expected
@@ -46,6 +46,12 @@ Func withUnsafeBytes(of:_:) is now without rethrows
 Func withUnsafeMutableBytes(of:_:) is now without rethrows
 Func withoutActuallyEscaping(_:do:) has generic signature change from <ClosureType, ResultType> to <ClosureType, ResultType, Failure where Failure : Swift.Error>
 Func withoutActuallyEscaping(_:do:) is now without rethrows
+Constructor Array.init(unsafeUninitializedCapacity:initializingWith:) has generic signature change from <Element> to <Element, E where E : Swift.Error>
+Constructor Array.init(unsafeUninitializedCapacity:initializingWith:) has parameter 1 type change from (inout Swift.UnsafeMutableBufferPointer<Element>, inout Swift.Int) throws -> Swift.Void to (inout Swift.UnsafeMutableBufferPointer<Element>, inout Swift.Int) throws(E) -> Swift.Void
+Constructor Array.init(unsafeUninitializedCapacity:initializingWith:) is now without rethrows
+Constructor ContiguousArray.init(unsafeUninitializedCapacity:initializingWith:) has generic signature change from <Element> to <Element, E where E : Swift.Error>
+Constructor ContiguousArray.init(unsafeUninitializedCapacity:initializingWith:) has parameter 1 type change from (inout Swift.UnsafeMutableBufferPointer<Element>, inout Swift.Int) throws -> Swift.Void to (inout Swift.UnsafeMutableBufferPointer<Element>, inout Swift.Int) throws(E) -> Swift.Void
+Constructor ContiguousArray.init(unsafeUninitializedCapacity:initializingWith:) is now without rethrows
 
 Protocol SIMDScalar has generic signature change from <Self == Self.SIMD16Storage.Scalar, Self.SIMD16Storage : Swift.SIMDStorage, Self.SIMD2Storage : Swift.SIMDStorage, Self.SIMD32Storage : Swift.SIMDStorage, Self.SIMD4Storage : Swift.SIMDStorage, Self.SIMD64Storage : Swift.SIMDStorage, Self.SIMD8Storage : Swift.SIMDStorage, Self.SIMDMaskScalar : Swift.FixedWidthInteger, Self.SIMDMaskScalar : Swift.SIMDScalar, Self.SIMDMaskScalar : Swift.SignedInteger, Self.SIMD16Storage.Scalar == Self.SIMD2Storage.Scalar, Self.SIMD2Storage.Scalar == Self.SIMD32Storage.Scalar, Self.SIMD32Storage.Scalar == Self.SIMD4Storage.Scalar, Self.SIMD4Storage.Scalar == Self.SIMD64Storage.Scalar, Self.SIMD64Storage.Scalar == Self.SIMD8Storage.Scalar> to <Self : Swift.BitwiseCopyable, Self == Self.SIMD16Storage.Scalar, Self.SIMD16Storage : Swift.SIMDStorage, Self.SIMD2Storage : Swift.SIMDStorage, Self.SIMD32Storage : Swift.SIMDStorage, Self.SIMD4Storage : Swift.SIMDStorage, Self.SIMD64Storage : Swift.SIMDStorage, Self.SIMD8Storage : Swift.SIMDStorage, Self.SIMDMaskScalar : Swift.FixedWidthInteger, Self.SIMDMaskScalar : Swift.SIMDScalar, Self.SIMDMaskScalar : Swift.SignedInteger, Self.SIMDMaskScalar == Self.SIMDMaskScalar.SIMDMaskScalar, Self.SIMD16Storage.Scalar == Self.SIMD2Storage.Scalar, Self.SIMD2Storage.Scalar == Self.SIMD32Storage.Scalar, Self.SIMD32Storage.Scalar == Self.SIMD4Storage.Scalar, Self.SIMD4Storage.Scalar == Self.SIMD64Storage.Scalar, Self.SIMD64Storage.Scalar == Self.SIMD8Storage.Scalar>
 
diff --git a/test/api-digester/breakage-allowlist.swift b/test/api-digester/breakage-allowlist.swift
index 4309ea6453c38..c09a6fe61c6bb 100644
--- a/test/api-digester/breakage-allowlist.swift
+++ b/test/api-digester/breakage-allowlist.swift
@@ -12,7 +12,7 @@
 
 // RUN: echo "ABI breakage: func foo() has been removed" > %t/incomplete-allowlist.txt
 // RUN: echo "ABI breakage: func foo() has been removed" > %t/complete-allowlist.txt
-// RUN: echo "ABI breakage: func bar() is a new API without @available attribute" >> %t/complete-allowlist.txt
+// RUN: echo "ABI breakage: func bar() is a new API without '@available'" >> %t/complete-allowlist.txt
 
 // RUN: %target-swift-frontend -disable-objc-attr-requires-foundation-module -emit-module -o %t.mod1/Foo.swiftmodule  %t.mod1/Foo.swift -parse-as-library -enable-library-evolution -emit-module-source-info -emit-module-source-info-path %t.mod1/Foo.swiftsourceinfo -emit-module-interface-path %t.mod1/Foo.swiftinterface -module-name Foo -swift-version 5
 
diff --git a/test/api-digester/dump-module.swift b/test/api-digester/dump-module.swift
index 9f37802413831..d6c4abefb94a5 100644
--- a/test/api-digester/dump-module.swift
+++ b/test/api-digester/dump-module.swift
@@ -1,19 +1,22 @@
 // REQUIRES: OS=macosx
+
 // RUN: %empty-directory(%t.mod)
 // RUN: %empty-directory(%t.sdk)
 // RUN: %empty-directory(%t.module-cache)
+
 // RUN: %target-swift-frontend -disable-objc-attr-requires-foundation-module -emit-module -o %t.mod/cake.swiftmodule %S/Inputs/cake.swift -parse-as-library -I %S/Inputs/ClangCake %clang-importer-sdk-nosource
 // RUN: %api-digester -dump-sdk -module cake -o %t.dump.json -module-cache-path %t.module-cache -swift-only -I %t.mod -I %S/Inputs/ClangCake %clang-importer-sdk-nosource -avoid-tool-args
-// RUN: diff -u %S/Outputs/cake.json %t.dump.json
+// RUN: diff -u %S/Outputs/dump-module/cake.json %t.dump.json
 // RUN: %api-digester -dump-sdk -module cake -o %t.dump.json -module-cache-path %t.module-cache -swift-only -I %t.mod -abi -I %S/Inputs/ClangCake %clang-importer-sdk-nosource -avoid-tool-args
-// RUN: diff -u %S/Outputs/cake-abi.json %t.dump.json
-// RUN: %api-digester -diagnose-sdk --input-paths %t.dump.json -input-paths %S/Outputs/cake.json
+// RUN: diff -u %S/Outputs/dump-module/cake-abi.json %t.dump.json
+
+// RUN: %api-digester -diagnose-sdk --input-paths %t.dump.json -input-paths %S/Outputs/dump-module/cake.json
 
 // Round-trip testing:
-// RUN: %api-digester -deserialize-sdk --input-paths %S/Outputs/cake.json -o %t.dump.json
-// RUN: diff -u %S/Outputs/cake.json %t.dump.json
-// RUN: %api-digester -deserialize-sdk --input-paths %S/Outputs/cake-abi.json -o %t.dump.json
-// RUN: diff -u %S/Outputs/cake-abi.json %t.dump.json
+// RUN: %api-digester -deserialize-sdk --input-paths %S/Outputs/dump-module/cake.json -o %t.dump.json
+// RUN: diff -u %S/Outputs/dump-module/cake.json %t.dump.json
+// RUN: %api-digester -deserialize-sdk --input-paths %S/Outputs/dump-module/cake-abi.json -o %t.dump.json
+// RUN: diff -u %S/Outputs/dump-module/cake-abi.json %t.dump.json
 
 // The input JSON files need to be modified when standard library declarations
 // are reordered. This is expected behavior and we simply shouldn't run the test
diff --git a/test/api-digester/serialized-diagnostics.swift b/test/api-digester/serialized-diagnostics.swift
index d311f0a185664..daf02cc451059 100644
--- a/test/api-digester/serialized-diagnostics.swift
+++ b/test/api-digester/serialized-diagnostics.swift
@@ -9,5 +9,5 @@
 // RUN: c-index-test -read-diagnostics %t/result.dia 2>&1 | %FileCheck %s -check-prefix CHECK-DIA
 
 // Ensure the 'api-digester-breaking-change' category is included in the serialized diagnostics file.
-// CHECK-DIA: warning: ABI breakage: enum Color is a new API without @available attribute [] [api-digester-breaking-change]
-// CHECK-STDERR: warning: ABI breakage: enum Color is a new API without @available attribute
+// CHECK-DIA: warning: ABI breakage: enum Color is a new API without '@available' [] [api-digester-breaking-change]
+// CHECK-STDERR: warning: ABI breakage: enum Color is a new API without '@available'
diff --git a/test/api-digester/stability-concurrency-abi.test b/test/api-digester/stability-concurrency-abi.test
index 3625780b555bf..8e8e24505f24f 100644
--- a/test/api-digester/stability-concurrency-abi.test
+++ b/test/api-digester/stability-concurrency-abi.test
@@ -111,7 +111,7 @@ Func SerialExecutor.enqueue(_:) has been added as a protocol requirement
 // while adding a new overload that accepts `Job` with new availability.
 // The ABI checker seems to be confused by this case.
 // rdar://106833284 (ABI checker confused with overload getting deprecated)
-Func Executor.enqueue(_:) is a new API without @available attribute
+Func Executor.enqueue(_:) is a new API without '@available'
 
 // Adopt #isolation in TaskLocal.withValue APIs
 Func TaskLocal.withValue(_:operation:file:line:) has been renamed to Func withValue(_:operation:isolation:file:line:)
@@ -128,6 +128,8 @@ Func withThrowingTaskGroup(of:returning:body:) has parameter 2 type change from
 Func withTaskGroup(of:returning:body:) has been renamed to Func withTaskGroup(of:returning:isolation:body:)
 Func withTaskGroup(of:returning:body:) has mangled name changing from '_Concurrency.withTaskGroup<A, B where A: Swift.Sendable>(of: A.Type, returning: B.Type, body: (inout Swift.TaskGroup<A>) async -> B) async -> B' to '_Concurrency.withTaskGroup<A, B where A: Swift.Sendable>(of: A.Type, returning: B.Type, isolation: isolated Swift.Optional<Swift.Actor>, body: (inout Swift.TaskGroup<A>) async -> B) async -> B'
 
+Func pthread_main_np() is a new API without '@available'
+
 // *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment above.)
 
 
diff --git a/test/api-digester/stability-stdlib-abi-with-array-cow-checks.test b/test/api-digester/stability-stdlib-abi-with-array-cow-checks.test
index abbf5b20d6311..bb9383096b737 100644
--- a/test/api-digester/stability-stdlib-abi-with-array-cow-checks.test
+++ b/test/api-digester/stability-stdlib-abi-with-array-cow-checks.test
@@ -58,8 +58,8 @@
 
 // Note: normally you'll need to add new entries to
 // `stability-stdlib-abi-without-asserts.test`, not this file.
-Func _COWChecksEnabled() is a new API without @available attribute
-Func _swift_isImmutableCOWBuffer(_:) is a new API without @available attribute
-Func _swift_setImmutableCOWBuffer(_:_:) is a new API without @available attribute
+Func _COWChecksEnabled() is a new API without '@available'
+Func _swift_isImmutableCOWBuffer(_:) is a new API without '@available'
+Func _swift_setImmutableCOWBuffer(_:_:) is a new API without '@available'
 
 // *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment above.)
diff --git a/test/api-digester/stability-stdlib-abi-with-asserts.test b/test/api-digester/stability-stdlib-abi-with-asserts.test
index 4fa4a5aa338d9..c4e41770a104c 100644
--- a/test/api-digester/stability-stdlib-abi-with-asserts.test
+++ b/test/api-digester/stability-stdlib-abi-with-asserts.test
@@ -58,13 +58,13 @@
 
 // Note: normally you'll need to add new entries to
 // `stability-stdlib-abi-without-asserts.test`, not this file.
-Func _collectReferencesInsideObject(_:) is a new API without @available attribute
-Func _loadDestroyTLSCounter() is a new API without @available attribute
-Func _measureRuntimeFunctionCountersDiffs(objects:_:) is a new API without @available attribute
-Protocol _RuntimeFunctionCountersStats is a new API without @available attribute
-Struct _GlobalRuntimeFunctionCountersState is a new API without @available attribute
-Struct _ObjectRuntimeFunctionCountersState is a new API without @available attribute
-Struct _RuntimeFunctionCounters is a new API without @available attribute
+Func _collectReferencesInsideObject(_:) is a new API without '@available'
+Func _loadDestroyTLSCounter() is a new API without '@available'
+Func _measureRuntimeFunctionCountersDiffs(objects:_:) is a new API without '@available'
+Protocol _RuntimeFunctionCountersStats is a new API without '@available'
+Struct _GlobalRuntimeFunctionCountersState is a new API without '@available'
+Struct _ObjectRuntimeFunctionCountersState is a new API without '@available'
+Struct _RuntimeFunctionCounters is a new API without '@available'
 
 // *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment above.)
 
diff --git a/test/api-digester/stability-stdlib-abi-without-asserts.test b/test/api-digester/stability-stdlib-abi-without-asserts.test
index b98522c9d99d1..1f3d391db78a3 100644
--- a/test/api-digester/stability-stdlib-abi-without-asserts.test
+++ b/test/api-digester/stability-stdlib-abi-without-asserts.test
@@ -49,18 +49,18 @@
 
 // *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment above.)
 
-Func _prespecialize() is a new API without @available attribute
-Func _stdlib_isOSVersionAtLeastOrVariantVersionAtLeast(_:_:_:_:_:_:) is a new API without @available attribute
-Func _diagnoseUnavailableCodeReached() is a new API without @available attribute
+Func _prespecialize() is a new API without '@available'
+Func _stdlib_isOSVersionAtLeastOrVariantVersionAtLeast(_:_:_:_:_:_:) is a new API without '@available'
+Func _diagnoseUnavailableCodeReached() is a new API without '@available'
 
 // These functions are not actually added to the ABI, but they had been a part of
 // the ABI exposed by the runtime library, so this is not breakage.
 // They are now referenced by @_extern(c) declarations in the standard library, but
 // api-digester cannot match them with the baseline symbols in the baseline runtime
 // library, which were not exposed by the baseline stdlib module.
-Func _swift_retainCount(_:) is a new API without @available attribute
-Func _swift_unownedRetainCount(_:) is a new API without @available attribute
-Func _swift_weakRetainCount(_:) is a new API without @available attribute
+Func _swift_retainCount(_:) is a new API without '@available'
+Func _swift_unownedRetainCount(_:) is a new API without '@available'
+Func _swift_weakRetainCount(_:) is a new API without '@available'
 // And these were temporarily added as ABI in https://github.com/apple/swift/pull/69352,
 // but then https://github.com/apple/swift/pull/71694 made them @_aeic before
 // they shipped anywhere, but not before they got into the ABI baseline. Fun!
@@ -130,13 +130,13 @@ Func _SequenceBox._map(_:) is now without rethrows
 Func UnsafeMutableRawBufferPointer.storeBytes(of:toByteOffset:as:) has been removed
 Func UnsafeMutableRawPointer.storeBytes(of:toByteOffset:as:) has been removed
 Func UnsafeMutableBufferPointer.assign(repeating:) has been removed
-Func UnsafeMutableBufferPointer.update(repeating:) is a new API without @available attribute
+Func UnsafeMutableBufferPointer.update(repeating:) is a new API without '@available'
 Func UnsafeMutablePointer.assign(from:count:) has been removed
-Func UnsafeMutablePointer.update(from:count:) is a new API without @available attribute
+Func UnsafeMutablePointer.update(from:count:) is a new API without '@available'
 Func UnsafeMutablePointer.assign(repeating:count:) has been removed
-Func UnsafeMutablePointer.update(repeating:count:) is a new API without @available attribute
+Func UnsafeMutablePointer.update(repeating:count:) is a new API without '@available'
 Func UnsafeMutablePointer.moveAssign(from:count:) has been removed
-Func UnsafeMutablePointer.moveUpdate(from:count:) is a new API without @available attribute
+Func UnsafeMutablePointer.moveUpdate(from:count:) is a new API without '@available'
 
 // These haven't actually been removed; they were renamed at the source level while
 // retaining their old mangled name. The source break was accepted as part of se-0370.
@@ -146,7 +146,7 @@ Func UnsafeMutableBufferPointer.initialize(from:) has return type change from (
 // This hasn't actually been removed; it was renamed at the source level while
 // retaining its old mangled/silgen name. The old source-level name is preserved
 // as an @_alwaysEmitIntoClient function. The source break was accepted as part of se-0405.
-Constructor String.init(validatingCString:) is a new API without @available attribute
+Constructor String.init(validatingCString:) is a new API without '@available'
 Constructor String.init(validatingUTF8:) has been removed
 
 // These haven't actually been removed; they are simply marked unavailable.
@@ -822,13 +822,20 @@ Func _SliceBuffer.withUnsafeBufferPointer(_:) has mangled name changing from 'Sw
 Func _SliceBuffer.withUnsafeMutableBufferPointer(_:) has been renamed to Func __abi_withUnsafeMutableBufferPointer(_:)
 Func _SliceBuffer.withUnsafeMutableBufferPointer(_:) has mangled name changing from 'Swift._SliceBuffer.withUnsafeMutableBufferPointer<A>((Swift.UnsafeMutableBufferPointer<A>) throws -> A1) throws -> A1' to 'Swift._SliceBuffer.__abi_withUnsafeMutableBufferPointer<A>((Swift.UnsafeMutableBufferPointer<A>) throws -> A1) throws -> A1'
 
+// Functions changed for typed throws
+Constructor Array.init(_unsafeUninitializedCapacity:initializingWith:) has been removed
+Func Array.withUnsafeBufferPointer(_:) has been removed
+Func ArraySlice.withUnsafeBufferPointer(_:) has been removed
+Func ContiguousArray.withUnsafeBufferPointer(_:) has been removed
+
 Struct String.Index has added a conformance to an existing protocol CustomDebugStringConvertible
 
 Struct CollectionOfOne is now with @_addressableForDependencies
+Struct _StringGuts is now with @_addressableForDependencies
 
-Enum _SwiftifyInfo is a new API without @available attribute
-Enum _SwiftifyExpr is a new API without @available attribute
-Enum _DependenceType is a new API without @available attribute
+Enum _SwiftifyInfo is a new API without '@available'
+Enum _SwiftifyExpr is a new API without '@available'
+Enum _DependenceType is a new API without '@available'
 
 Protocol CodingKey has added inherited protocol SendableMetatype
 Protocol Error has added inherited protocol SendableMetatype
@@ -855,6 +862,10 @@ Var UnsafeMutableBufferPointer.indices has mangled name changing from 'Swift.Uns
 Var UnsafeMutableBufferPointer.indices is now with @_preInverseGenerics
 Func !=(_:_:) has been removed
 Func ==(_:_:) has been removed
+Func ==(_:_:) has generic signature change from to <T where T : Swift.RawRepresentable, T.RawValue : Swift.Equatable>
+Func ==(_:_:) has mangled name changing from 'Swift.== infix(Swift.Optional<Any.Type>, Swift.Optional<Any.Type>) -> Swift.Bool' to 'Swift.== infix<A where A: Swift.RawRepresentable, A.RawValue: Swift.Equatable>(A, A) -> Swift.Bool'
+Func ==(_:_:) has parameter 0 type change from (any Any.Type)? to τ_0_0
+Func ==(_:_:) has parameter 1 type change from (any Any.Type)? to τ_0_0                              
 Func type(of:) has been removed
 
 // *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment above.)
diff --git a/test/attr/ApplicationMain/attr_NSApplicationMain.swift b/test/attr/ApplicationMain/attr_NSApplicationMain.swift
index 71c5f361976b5..2764ff1a822f6 100644
--- a/test/attr/ApplicationMain/attr_NSApplicationMain.swift
+++ b/test/attr/ApplicationMain/attr_NSApplicationMain.swift
@@ -7,6 +7,6 @@
 import AppKit
 
 @NSApplicationMain // expected-deprecated-warning {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-1 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-1 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate: NSObject, NSApplicationDelegate {
 }
diff --git a/test/attr/ApplicationMain/attr_NSApplicationMain_inherited.swift b/test/attr/ApplicationMain/attr_NSApplicationMain_inherited.swift
index c99e62c4641b3..bcadf881d26e8 100644
--- a/test/attr/ApplicationMain/attr_NSApplicationMain_inherited.swift
+++ b/test/attr/ApplicationMain/attr_NSApplicationMain_inherited.swift
@@ -9,6 +9,6 @@ import AppKit
 class DelegateBase : NSObject, NSApplicationDelegate { }
 
 @NSApplicationMain // expected-deprecated-warning {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-1 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-1 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate : DelegateBase { }
 
diff --git a/test/attr/ApplicationMain/attr_NSApplicationMain_multi_file/another_delegate.swift b/test/attr/ApplicationMain/attr_NSApplicationMain_multi_file/another_delegate.swift
index d75ef3f959e5e..9cc6278f0c77c 100644
--- a/test/attr/ApplicationMain/attr_NSApplicationMain_multi_file/another_delegate.swift
+++ b/test/attr/ApplicationMain/attr_NSApplicationMain_multi_file/another_delegate.swift
@@ -1,10 +1,10 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify %s %S/delegate.swift
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated %s %S/delegate.swift
 
 // Serialized partial AST support:
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -module-name main -emit-module-path %t.swiftmodule -primary-file %s %S/delegate.swift
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -module-name main -parse-as-library -typecheck %t.swiftmodule -primary-file %S/delegate.swift -verify -verify-ignore-unknown
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -module-name main -parse-as-library -typecheck %t.swiftmodule -primary-file %S/delegate.swift -verify -verify-ignore-unrelated -verify-ignore-unknown
 
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -module-name main -parse-as-library -typecheck -enable-upcoming-feature DeprecateApplicationMain %t.swiftmodule -primary-file %S/delegate.swift -verify -verify-ignore-unknown -verify-additional-prefix deprecated-
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -module-name main -parse-as-library -typecheck -enable-upcoming-feature DeprecateApplicationMain %t.swiftmodule -primary-file %S/delegate.swift -verify -verify-ignore-unrelated -verify-ignore-unknown -verify-additional-prefix deprecated-
 
 // REQUIRES: objc_interop
 // REQUIRES: swift_feature_DeprecateApplicationMain
@@ -13,7 +13,7 @@ import AppKit
 
 @NSApplicationMain // expected-error{{'NSApplicationMain' attribute can only apply to one class in a module}}
 // expected-deprecated-warning@-1 {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class EvilDelegate: NSObject, NSApplicationDelegate {
 }
 
diff --git a/test/attr/ApplicationMain/attr_NSApplicationMain_multi_file/delegate.swift b/test/attr/ApplicationMain/attr_NSApplicationMain_multi_file/delegate.swift
index bd3c80f49b06d..9cd54f61b1183 100644
--- a/test/attr/ApplicationMain/attr_NSApplicationMain_multi_file/delegate.swift
+++ b/test/attr/ApplicationMain/attr_NSApplicationMain_multi_file/delegate.swift
@@ -9,7 +9,7 @@ import AppKit
 
 @NSApplicationMain // expected-error{{'NSApplicationMain' attribute can only apply to one class in a module}}
 // expected-deprecated-warning@-1 {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate: NSObject, NSApplicationDelegate {
 }
 
diff --git a/test/attr/ApplicationMain/attr_NSApplicationMain_multiple.swift b/test/attr/ApplicationMain/attr_NSApplicationMain_multiple.swift
index 213a6eb6de49c..9f071ad81e35f 100644
--- a/test/attr/ApplicationMain/attr_NSApplicationMain_multiple.swift
+++ b/test/attr/ApplicationMain/attr_NSApplicationMain_multiple.swift
@@ -9,18 +9,18 @@ import AppKit
 
 @NSApplicationMain // expected-error{{'NSApplicationMain' attribute can only apply to one class in a module}}
 // expected-deprecated-warning@-1 {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate1: NSObject, NSApplicationDelegate {
 }
 
 @NSApplicationMain // expected-error{{'NSApplicationMain' attribute can only apply to one class in a module}}
 // expected-deprecated-warning@-1 {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate2: NSObject, NSApplicationDelegate {
 }
 
 @NSApplicationMain // expected-error{{'NSApplicationMain' attribute can only apply to one class in a module}}
 // expected-deprecated-warning@-1 {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate3: NSObject, NSApplicationDelegate {
 }
diff --git a/test/attr/ApplicationMain/attr_NSApplicationMain_not_NSApplicationDelegate.swift b/test/attr/ApplicationMain/attr_NSApplicationMain_not_NSApplicationDelegate.swift
index 23f25e4dc76b5..bfee9e2b13c06 100644
--- a/test/attr/ApplicationMain/attr_NSApplicationMain_not_NSApplicationDelegate.swift
+++ b/test/attr/ApplicationMain/attr_NSApplicationMain_not_NSApplicationDelegate.swift
@@ -8,6 +8,6 @@ import AppKit
 
 @NSApplicationMain // expected-error{{'NSApplicationMain' class must conform to the 'NSApplicationDelegate' protocol}}
 // expected-deprecated-warning@-1 {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyNonDelegate {
 }
diff --git a/test/attr/ApplicationMain/attr_NSApplicationMain_swift6.swift b/test/attr/ApplicationMain/attr_NSApplicationMain_swift6.swift
index c546195f8ac03..0006d1f74b52d 100644
--- a/test/attr/ApplicationMain/attr_NSApplicationMain_swift6.swift
+++ b/test/attr/ApplicationMain/attr_NSApplicationMain_swift6.swift
@@ -5,6 +5,6 @@
 import AppKit
 
 @NSApplicationMain // expected-error {{'NSApplicationMain' is deprecated}}
-// expected-note@-1 {{use @main instead}} {{1-19=@main}}
+// expected-note@-1 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate: NSObject, NSApplicationDelegate {
 }
diff --git a/test/attr/ApplicationMain/attr_NSApplicationMain_with_main/delegate.swift b/test/attr/ApplicationMain/attr_NSApplicationMain_with_main/delegate.swift
index d51fe6479b49c..f973163473ec8 100644
--- a/test/attr/ApplicationMain/attr_NSApplicationMain_with_main/delegate.swift
+++ b/test/attr/ApplicationMain/attr_NSApplicationMain_with_main/delegate.swift
@@ -9,7 +9,7 @@ import AppKit
 
 @NSApplicationMain // expected-error{{'NSApplicationMain' attribute cannot be used in a module that contains top-level code}}
 // expected-deprecated-warning@-1 {{'NSApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate: NSObject, NSApplicationDelegate {
 }
 
diff --git a/test/attr/ApplicationMain/attr_UIApplicationMain.swift b/test/attr/ApplicationMain/attr_UIApplicationMain.swift
index 97bbdee6c32a2..b7c782471a102 100644
--- a/test/attr/ApplicationMain/attr_UIApplicationMain.swift
+++ b/test/attr/ApplicationMain/attr_UIApplicationMain.swift
@@ -7,6 +7,6 @@
 import UIKit
 
 @UIApplicationMain // expected-deprecated-warning {{'UIApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-1 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-1 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate: NSObject, UIApplicationDelegate {
 }
diff --git a/test/attr/ApplicationMain/attr_UIApplicationMain_inherited.swift b/test/attr/ApplicationMain/attr_UIApplicationMain_inherited.swift
index b6243bf7dc7c7..389f1f237c4c7 100644
--- a/test/attr/ApplicationMain/attr_UIApplicationMain_inherited.swift
+++ b/test/attr/ApplicationMain/attr_UIApplicationMain_inherited.swift
@@ -9,6 +9,6 @@ import UIKit
 class DelegateBase : NSObject, UIApplicationDelegate { }
 
 @UIApplicationMain // expected-deprecated-warning {{'UIApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-1 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-1 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate : DelegateBase { }
 
diff --git a/test/attr/ApplicationMain/attr_UIApplicationMain_multiple.swift b/test/attr/ApplicationMain/attr_UIApplicationMain_multiple.swift
index d66ec5d12cb37..c4d8d072b1f4c 100644
--- a/test/attr/ApplicationMain/attr_UIApplicationMain_multiple.swift
+++ b/test/attr/ApplicationMain/attr_UIApplicationMain_multiple.swift
@@ -8,18 +8,18 @@ import UIKit
 
 @UIApplicationMain // expected-error{{'UIApplicationMain' attribute can only apply to one class in a module}}
 // expected-deprecated-warning@-1 {{'UIApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate1: NSObject, UIApplicationDelegate {
 }
 
 @UIApplicationMain // expected-error{{'UIApplicationMain' attribute can only apply to one class in a module}}
 // expected-deprecated-warning@-1 {{'UIApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate2: NSObject, UIApplicationDelegate {
 }
 
 @UIApplicationMain // expected-error{{'UIApplicationMain' attribute can only apply to one class in a module}}
 // expected-deprecated-warning@-1 {{'UIApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate3: NSObject, UIApplicationDelegate {
 }
diff --git a/test/attr/ApplicationMain/attr_UIApplicationMain_not_UIApplicationDelegate.swift b/test/attr/ApplicationMain/attr_UIApplicationMain_not_UIApplicationDelegate.swift
index 650379d8a58c8..9c0a35ae9ceb0 100644
--- a/test/attr/ApplicationMain/attr_UIApplicationMain_not_UIApplicationDelegate.swift
+++ b/test/attr/ApplicationMain/attr_UIApplicationMain_not_UIApplicationDelegate.swift
@@ -8,6 +8,6 @@ import UIKit
 
 @UIApplicationMain // expected-error{{'UIApplicationMain' class must conform to the 'UIApplicationDelegate' protocol}}
 // expected-deprecated-warning@-1 {{'UIApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyNonDelegate {
 }
diff --git a/test/attr/ApplicationMain/attr_UIApplicationMain_swift6.swift b/test/attr/ApplicationMain/attr_UIApplicationMain_swift6.swift
index b4fdd3b457b3d..82c311cd7eb50 100644
--- a/test/attr/ApplicationMain/attr_UIApplicationMain_swift6.swift
+++ b/test/attr/ApplicationMain/attr_UIApplicationMain_swift6.swift
@@ -5,6 +5,6 @@
 import UIKit
 
 @UIApplicationMain // expected-error {{'UIApplicationMain' is deprecated}}
-// expected-note@-1 {{use @main instead}} {{1-19=@main}}
+// expected-note@-1 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate: NSObject, UIApplicationDelegate {
 }
diff --git a/test/attr/ApplicationMain/attr_UIApplicationMain_with_main/delegate.swift b/test/attr/ApplicationMain/attr_UIApplicationMain_with_main/delegate.swift
index f0a46f874fa5f..974dd1eba4652 100644
--- a/test/attr/ApplicationMain/attr_UIApplicationMain_with_main/delegate.swift
+++ b/test/attr/ApplicationMain/attr_UIApplicationMain_with_main/delegate.swift
@@ -9,7 +9,7 @@ import UIKit
 
 @UIApplicationMain // expected-error{{'UIApplicationMain' attribute cannot be used in a module that contains top-level code}}
 // expected-deprecated-warning@-1 {{'UIApplicationMain' is deprecated; this is an error in the Swift 6 language mode}}
-// expected-deprecated-note@-2 {{use @main instead}} {{1-19=@main}}
+// expected-deprecated-note@-2 {{use '@main' instead}} {{1-19=@main}}
 class MyDelegate: NSObject, UIApplicationDelegate {
 }
 
diff --git a/test/attr/ApplicationMain/attr_main_arguments.swift b/test/attr/ApplicationMain/attr_main_arguments.swift
index 758f8a6a9447b..592aee5b76cd7 100644
--- a/test/attr/ApplicationMain/attr_main_arguments.swift
+++ b/test/attr/ApplicationMain/attr_main_arguments.swift
@@ -1,8 +1,11 @@
 // RUN: %target-swift-frontend -typecheck -parse-as-library -verify %s
 
-@main // expected-error{{'MyBase' is annotated with @main and must provide a main static function}}
+@main // expected-error{{'MyBase' is annotated with '@main' and must provide a main static function}}
+// expected-note@-1{{add 'static func main()'}} {{8:16-16=\n    static func main() {\n        <#code#>\n    }\n}}
+// expected-note@-2{{add 'static func main() throws'}} {{8:16-16=\n    static func main() throws {\n        <#code#>\n    }\n}}
+// expected-note@-3{{add 'static func main() async'}} {{8:16-16=\n    static func main() async {\n        <#code#>\n    }\n}}
+// expected-note@-4{{add 'static func main() async throws'}} {{8:16-16=\n    static func main() async throws {\n        <#code#>\n    }\n}}
 struct MyBase {
   static func main(_ argc: Int, _ argv: [String]) {
   }
 }
-
diff --git a/test/attr/ApplicationMain/attr_main_dynamicCallable.swift b/test/attr/ApplicationMain/attr_main_dynamicCallable.swift
index 05de870db44da..efc3cb49a800e 100644
--- a/test/attr/ApplicationMain/attr_main_dynamicCallable.swift
+++ b/test/attr/ApplicationMain/attr_main_dynamicCallable.swift
@@ -1,6 +1,10 @@
 // RUN: %target-swift-frontend -typecheck -parse-as-library -verify %s
 
-@main // expected-error{{'Foo' is annotated with @main and must provide a main static function}}
+@main // expected-error{{'Foo' is annotated with '@main' and must provide a main static function}}
+// expected-note@-1{{add 'static func main()'}} {{8:13-13=\n    static func main() {\n        <#code#>\n    }\n}}
+// expected-note@-2{{add 'static func main() throws'}} {{8:13-13=\n    static func main() throws {\n        <#code#>\n    }\n}}
+// expected-note@-3{{add 'static func main() async'}} {{8:13-13=\n    static func main() async {\n        <#code#>\n    }\n}}
+// expected-note@-4{{add 'static func main() async throws'}} {{8:13-13=\n    static func main() async throws {\n        <#code#>\n    }\n}}
 struct Foo {
   @dynamicCallable
   struct main {
diff --git a/test/attr/ApplicationMain/attr_main_dynamicMemberLookup.swift b/test/attr/ApplicationMain/attr_main_dynamicMemberLookup.swift
index 63382fefbf4ed..daa35621e6a67 100644
--- a/test/attr/ApplicationMain/attr_main_dynamicMemberLookup.swift
+++ b/test/attr/ApplicationMain/attr_main_dynamicMemberLookup.swift
@@ -1,10 +1,13 @@
 // RUN: %target-swift-frontend -typecheck -parse-as-library -verify %s
 
-@main @dynamicMemberLookup // expected-error{{'Main' is annotated with @main and must provide a main static function}}
+@main @dynamicMemberLookup // expected-error{{'Main' is annotated with '@main' and must provide a main static function}}
+// expected-note@-1{{add 'static func main()'}} {{8:14-14=\n    static func main() {\n        <#code#>\n    }\n}}
+// expected-note@-2{{add 'static func main() throws'}} {{8:14-14=\n    static func main() throws {\n        <#code#>\n    }\n}}
+// expected-note@-3{{add 'static func main() async'}} {{8:14-14=\n    static func main() async {\n        <#code#>\n    }\n}}
+// expected-note@-4{{add 'static func main() async throws'}} {{8:14-14=\n    static func main() async throws {\n        <#code#>\n    }\n}}
 struct Main {
     subscript(dynamicMember member: String) -> () -> Void {
         return {
         }
     }
 }
-
diff --git a/test/attr/ApplicationMain/attr_main_extension_nofunc.swift b/test/attr/ApplicationMain/attr_main_extension_nofunc.swift
index 33f4ea1ccd297..5df0e1141d6c3 100644
--- a/test/attr/ApplicationMain/attr_main_extension_nofunc.swift
+++ b/test/attr/ApplicationMain/attr_main_extension_nofunc.swift
@@ -3,8 +3,10 @@
 class EntryPoint {
 }
 
-@main // expected-error{{'EntryPoint' is annotated with @main and must provide a main static function}}
+@main // expected-error{{'EntryPoint' is annotated with '@main' and must provide a main static function}}
+// expected-note@-1{{add 'static func main()'}} {{11:23-23=\n    static func main() {\n        <#code#>\n    }\n}}
+// expected-note@-2{{add 'static func main() throws'}} {{11:23-23=\n    static func main() throws {\n        <#code#>\n    }\n}}
+// expected-note@-3{{add 'static func main() async'}} {{11:23-23=\n    static func main() async {\n        <#code#>\n    }\n}}
+// expected-note@-4{{add 'static func main() async throws'}} {{11:23-23=\n    static func main() async throws {\n        <#code#>\n    }\n}}
 extension EntryPoint {
 }
-
-
diff --git a/test/attr/ApplicationMain/attr_main_instance.swift b/test/attr/ApplicationMain/attr_main_instance.swift
index a82b00493bfab..13d6a417ea8c6 100644
--- a/test/attr/ApplicationMain/attr_main_instance.swift
+++ b/test/attr/ApplicationMain/attr_main_instance.swift
@@ -1,8 +1,23 @@
 // RUN: %target-swift-frontend -typecheck -parse-as-library -verify %s
 
-@main // expected-error{{'MyBase' is annotated with @main and must provide a main static function}}
+@main // expected-error{{'MyBase' is annotated with '@main' and must provide a main static function}}
+// expected-note@-1{{add 'static func main()'}} {{8:15-15=\n    static func main() {\n        <#code#>\n    }\n}}
+// expected-note@-2{{add 'static func main() throws'}} {{8:15-15=\n    static func main() throws {\n        <#code#>\n    }\n}}
+// expected-note@-3{{add 'static func main() async'}} {{8:15-15=\n    static func main() async {\n        <#code#>\n    }\n}}
+// expected-note@-4{{add 'static func main() async throws'}} {{8:15-15=\n    static func main() async throws {\n        <#code#>\n    }\n}}
 class MyBase {
   func main() {
   }
 }
 
+enum Nested {
+  @main // expected-error{{'MyBase' is annotated with '@main' and must provide a main static function}}
+  // expected-note@-1{{add 'static func main()'}} {{19:17-17=\n      static func main() {\n          <#code#>\n      }\n}}
+  // expected-note@-2{{add 'static func main() throws'}} {{19:17-17=\n      static func main() throws {\n          <#code#>\n      }\n}}
+  // expected-note@-3{{add 'static func main() async'}} {{19:17-17=\n      static func main() async {\n          <#code#>\n      }\n}}
+  // expected-note@-4{{add 'static func main() async throws'}} {{19:17-17=\n      static func main() async throws {\n          <#code#>\n      }\n}}
+  class MyBase {
+    func main() {
+    }
+  }
+}
diff --git a/test/attr/ApplicationMain/attr_main_instance_without_async_support.swift b/test/attr/ApplicationMain/attr_main_instance_without_async_support.swift
new file mode 100644
index 0000000000000..c9d1a635d4485
--- /dev/null
+++ b/test/attr/ApplicationMain/attr_main_instance_without_async_support.swift
@@ -0,0 +1,10 @@
+// RUN: %target-swift-frontend -typecheck -parse-as-library -target %target-swift-5.0-abi-triple -verify %s
+// REQUIRES: OS=macosx && CPU=x86_64
+
+@main // expected-error{{'MyBaseWithoutAsyncSupport' is annotated with '@main' and must provide a main static function}}
+// expected-note@-1{{add 'static func main()'}} {{7:34-34=\n    static func main() {\n        <#code#>\n    }\n}}
+// expected-note@-2{{add 'static func main() throws'}} {{7:34-34=\n    static func main() throws {\n        <#code#>\n    }\n}}
+class MyBaseWithoutAsyncSupport {
+  func main() {
+  }
+}
diff --git a/test/attr/ApplicationMain/attr_main_multi_file/main2.swift b/test/attr/ApplicationMain/attr_main_multi_file/main2.swift
index 5717584488722..337851b5488ca 100644
--- a/test/attr/ApplicationMain/attr_main_multi_file/main2.swift
+++ b/test/attr/ApplicationMain/attr_main_multi_file/main2.swift
@@ -1,8 +1,8 @@
-// RUN: %target-swift-frontend -typecheck -verify %s %S/main1.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %s %S/main1.swift
 
 // Serialized partial AST support:
 // RUN: %target-swift-frontend -module-name main -emit-module-path %t.swiftmodule -primary-file %s %S/main1.swift
-// RUN: %target-swift-frontend -module-name main -parse-as-library -typecheck %t.swiftmodule -primary-file %S/main1.swift -verify -verify-ignore-unknown
+// RUN: %target-swift-frontend -module-name main -parse-as-library -typecheck %t.swiftmodule -primary-file %S/main1.swift -verify -verify-ignore-unrelated -verify-ignore-unknown
 
 @main // expected-error{{'main' attribute can only apply to one type in a module}}
 class EvilMain {
diff --git a/test/attr/ApplicationMain/attr_main_return.swift b/test/attr/ApplicationMain/attr_main_return.swift
index 0039e8642b696..ef7439217bef5 100644
--- a/test/attr/ApplicationMain/attr_main_return.swift
+++ b/test/attr/ApplicationMain/attr_main_return.swift
@@ -1,8 +1,11 @@
 // RUN: %target-swift-frontend -typecheck -parse-as-library -verify %s
 
-@main // expected-error{{'MyBase' is annotated with @main and must provide a main static function}}
+@main // expected-error{{'MyBase' is annotated with '@main' and must provide a main static function}}
+// expected-note@-1{{add 'static func main()'}} {{8:16-16=\n    static func main() {\n        <#code#>\n    }\n}}
+// expected-note@-2{{add 'static func main() throws'}} {{8:16-16=\n    static func main() throws {\n        <#code#>\n    }\n}}
+// expected-note@-3{{add 'static func main() async'}} {{8:16-16=\n    static func main() async {\n        <#code#>\n    }\n}}
+// expected-note@-4{{add 'static func main() async throws'}} {{8:16-16=\n    static func main() async throws {\n        <#code#>\n    }\n}}
 struct MyBase {
   static func main() -> Int {
   }
 }
-
diff --git a/test/attr/ApplicationMain/attr_main_struct_from_two_protocols_one_missing.swift b/test/attr/ApplicationMain/attr_main_struct_from_two_protocols_one_missing.swift
index 483a7b90db9b2..75d06b22f02f5 100644
--- a/test/attr/ApplicationMain/attr_main_struct_from_two_protocols_one_missing.swift
+++ b/test/attr/ApplicationMain/attr_main_struct_from_two_protocols_one_missing.swift
@@ -15,9 +15,12 @@ extension Runnable where Self : OtherThing {
     }
 }
 
-@main //expected-error{{'EntryPoint' is annotated with @main and must provide a main static function}}
+@main //expected-error{{'EntryPoint' is annotated with '@main' and must provide a main static function}}
+// expected-note@-1{{add 'static func main()'}} {{23:31-31=\n    static func main() {\n        <#code#>\n    }\n}}
+// expected-note@-2{{add 'static func main() throws'}} {{23:31-31=\n    static func main() throws {\n        <#code#>\n    }\n}}
+// expected-note@-3{{add 'static func main() async'}} {{23:31-31=\n    static func main() async {\n        <#code#>\n    }\n}}
+// expected-note@-4{{add 'static func main() async throws'}} {{23:31-31=\n    static func main() async throws {\n        <#code#>\n    }\n}}
 struct EntryPoint : Runnable {
   func run() {
   }
 }
-
diff --git a/test/attr/ApplicationMain/attr_main_throws.swift b/test/attr/ApplicationMain/attr_main_throws.swift
index 959a0f21b8eec..df6493ed0679a 100644
--- a/test/attr/ApplicationMain/attr_main_throws.swift
+++ b/test/attr/ApplicationMain/attr_main_throws.swift
@@ -7,7 +7,7 @@ struct MyBase {
   }
 }
 
-// CHECK-AST: (func_decl {{.*}} implicit "$main()" interface_type="(MyBase.Type) -> () throws -> ()" access=internal static
+// CHECK-AST: (func_decl {{.*}} implicit range=[{{.*}}:[[@LINE-6]]:1 - line:[[@LINE-6]]:1] "$main()" interface_type="(MyBase.Type) -> () throws -> ()" access=internal static
 // CHECK-AST-NEXT:  (parameter "self" {{.*}})
 // CHECK-AST-NEXT:  (parameter_list)
 // CHECK-AST-NEXT:  (brace_stmt implicit
diff --git a/test/attr/Inputs/access-note-gen.py b/test/attr/Inputs/access-note-gen.py
index 5fe4df09a58f8..e33db020209b5 100644
--- a/test/attr/Inputs/access-note-gen.py
+++ b/test/attr/Inputs/access-note-gen.py
@@ -81,8 +81,8 @@ def offsetify(*offsets):
                                r'([^}\\]*(?:(?:\}?\\.|\}[^}])[^}\\]*)*)' +
                                r'\}\}')
 
-"""Matches the string 'marked @objc'."""
-marked_objc_re = re.compile(r'marked @objc')
+"""Matches the string "marked '@objc'"."""
+marked_objc_re = re.compile(r"marked '@objc'")
 
 """Matches any non-none fix-it expectation."""
 fixit_re = re.compile(r'{{\d+-\d+=[^}]*}}')
@@ -103,7 +103,7 @@ def adjust_comments(offset, inserted_attr, comment_str):
                                                m.group(2) + prefix + m.group(3) +
                                                suffix,
                                      adjusted)
-    adjusted = marked_objc_re.sub(u"marked @objc by an access note", adjusted)
+    adjusted = marked_objc_re.sub(u"marked '@objc' by an access note", adjusted)
     adjusted = fixit_re.sub(u"{{none}}", adjusted)
 
     return u"// [expectations adjusted] " + adjusted
diff --git a/test/attr/accessibility.swift b/test/attr/accessibility.swift
index d557b4765c74c..6b233d89bd1ba 100644
--- a/test/attr/accessibility.swift
+++ b/test/attr/accessibility.swift
@@ -69,32 +69,38 @@ package(set) // expected-note {{previous modifier specified here}}
 public(set) // expected-error {{multiple incompatible access-level modifiers specified}}
 public var customSetterDuplicateAttr3 = 0
 
-private(get) // expected-error{{expected 'set' as subject of 'private' modifier}}
+private(get) // expected-error{{expected 'set' as subject of 'private' modifier}} {{9-12=set}}
 var invalidSubject = 0
 
-private(42) // expected-error{{expected 'set' as subject of 'private' modifier}}
+private(42) // expected-error{{expected 'set' as subject of 'private' modifier}} {{9-11=set}}
 var invalidSubject2 = 0
 
 private(a bunch of random tokens) // expected-error{{expected 'set' as subject of 'private' modifier}} expected-error{{expected declaration}}
 var invalidSubject3 = 0
 
 
-package(get) // expected-error{{expected 'set' as subject of 'package' modifier}}
+package(get) // expected-error{{expected 'set' as subject of 'package' modifier}} {{9-12=set}}
 var invalidSubject4 = 0
 
-package(42) // expected-error{{expected 'set' as subject of 'package' modifier}}
+package(42) // expected-error{{expected 'set' as subject of 'package' modifier}} {{9-11=set}}
 var invalidSubject5 = 0
 
-private(set // expected-error{{expected ')' in 'private' modifier}}
+private((())) // expected-error{{expected 'set' as subject of 'private' modifier}} expected-error{{expected declaration}}
+var invalidSubject6 = 0
+
+private( missingFunc(_ x: Int) -> Bool // expected-error{{expected 'set' as subject of 'private' modifier}} {{9-9=set)}} expected-error{{expected declaration}}
+let independentVar1 = 0
+
+private(set // expected-error{{expected ')' in 'private' modifier}} {{12-12=)}}
 var unterminatedSubject = 0
 
-private(42 // expected-error{{expected 'set' as subject of 'private' modifier}} expected-error{{expected declaration}}
+private(42 // expected-error{{expected 'set' as subject of 'private' modifier}} {{9-11=set)}}
 var unterminatedInvalidSubject = 0
 
-private() // expected-error{{expected 'set' as subject of 'private' modifier}}
+private() // expected-error{{expected 'set' as subject of 'private' modifier}} {{9-9=set}}
 var emptySubject = 0
 
-private( // expected-error{{expected 'set' as subject of 'private' modifier}}
+private( // expected-error{{expected 'set' as subject of 'private' modifier}} {{9-9=set)}}
 var unterminatedEmptySubject = 0
 
 // Check that the parser made it here.
@@ -341,3 +347,10 @@ package extension PkgGenericStruct where Param: InternalProto {} // expected-err
 extension PkgGenericStruct where Param: InternalProto {
   package func foo() {} // expected-error {{cannot declare a package instance method in an extension with internal requirements}} {{3-10=internal}}
 }
+
+func f() {}
+private( // expected-error{{expected 'set' as subject of 'private' modifier}} {{9-9=set)}}
+if true { // expected-error{{expected declaration}} {{none}}
+  f()
+}
+var unrelatedVar = "Swift"
diff --git a/test/attr/attr_abi.swift b/test/attr/attr_abi.swift
index 1409d75bf0fdf..724c6d0a67cf0 100644
--- a/test/attr/attr_abi.swift
+++ b/test/attr/attr_abi.swift
@@ -1,11 +1,9 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature Extern -enable-experimental-feature ABIAttribute -enable-experimental-feature AddressableParameters -enable-experimental-feature NoImplicitCopy -enable-experimental-feature SymbolLinkageMarkers -enable-experimental-feature StrictMemorySafety -enable-experimental-feature LifetimeDependence -enable-experimental-feature CImplementation -enable-experimental-feature ExecutionAttribute -import-bridging-header %S/Inputs/attr_abi.h -parse-as-library -Rabi-inference -debugger-support
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature Extern -enable-experimental-feature AddressableParameters -enable-experimental-feature NoImplicitCopy -enable-experimental-feature SymbolLinkageMarkers -enable-experimental-feature StrictMemorySafety -enable-experimental-feature Lifetimes -enable-experimental-feature CImplementation -import-bridging-header %S/Inputs/attr_abi.h -parse-as-library -debugger-support
 
-// REQUIRES: swift_feature_ABIAttribute
 // REQUIRES: swift_feature_AddressableParameters
 // REQUIRES: swift_feature_CImplementation
-// REQUIRES: swift_feature_ExecutionAttribute
 // REQUIRES: swift_feature_Extern
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 // REQUIRES: swift_feature_NoImplicitCopy
 // REQUIRES: swift_feature_StrictMemorySafety
 // REQUIRES: swift_feature_SymbolLinkageMarkers
@@ -280,17 +278,20 @@ var async11Var: Int { get async { fatalError() } }
 // PBD shape checking
 //
 
-@abi(var x1, y1: Int) // expected-error {{cannot give pattern binding the ABI of a binding with more patterns}}
-var x1: Int = 0
+@abi(var x1, y1: Int)
+var x1: Int = 0 // expected-error {{'abi' attribute can only be applied to a single var; declare each var separately}}
 
 @abi(var x2: Int)
-var x2 = 0, y2: Int = 0 // expected-error {{cannot give pattern binding the ABI of a binding with fewer patterns}}
+var x2 = 0, y2: Int = 0 // expected-error {{'abi' attribute can only be applied to a single var; declare each var separately}}
 
-@abi(var (x3, y3): (Int, Int), (a3, b3): (Int, Int)) // expected-error {{no match for ABI var 'b3'}}
-var (x3, y3): (Int, Int) = (0, 0), a3: Int = 0
+@abi(var (x3, y3): (Int, Int), (a3, b3): (Int, Int))
+var (x3, y3): (Int, Int) = (0, 0), a3: Int = 0 // expected-error {{'abi' attribute can only be applied to a single var; declare each var separately}}
 
 @abi(var (x4, y4): (Int, Int), a4: Int)
-var (x4, y4): (Int, Int) = (0, 0), (a4, b4): (Int, Int) = (0, 0) // expected-error {{no match for var 'b4' in the ABI}}
+var (x4, y4): (Int, Int) = (0, 0), (a4, b4): (Int, Int) = (0, 0) // expected-error {{'abi' attribute can only be applied to a single var; declare each var separately}}
+
+@abi(var x5: Int)
+var x5: Int = 0
 
 //
 // Redeclaration diagnostics
@@ -948,7 +949,7 @@ func addressableTest(
     _ e: @MainActor () -> AnyObject,
     _ f: (isolated MainActor) -> AnyObject,
     _ g: @isolated(any) () -> AnyObject, // expected-error {{parameter 'g' type '@isolated(any) () -> AnyObject' in '@abi' should match '() -> AnyObject'}}
-    _ h: @execution(caller) () async -> AnyObject,
+    _ h: nonisolated(nonsending) () async -> AnyObject,
     _ i: () -> AnyObject, // expected-error {{parameter 'i' type '() -> AnyObject' in '@abi' should match '@isolated(any) () -> AnyObject'}}
     _ j: () async -> Void,
     _ k: () -> Void, // expected-error {{parameter 'k' type '() -> Void' in '@abi' should match '() async -> Void'}}
@@ -991,18 +992,18 @@ func fnExtInfoTest(
 // FIXME: Not sure how to reach tryNormalizeOutermostType() generic func
 
 @abi(
-  func testMarkerProtocols<A, B: Sendable>(
-    _: A, _: B,
-    _: Any, _: Sendable,
-    _: AnyKeyPath, _: AnyKeyPath & Sendable,
-    _: Any, _: Sendable & BitwiseCopyable
+  func testMarkerProtocols<A, B: Sendable, C, D: SendableMetatype>(
+    _: A, _: B, _: C, _: D,
+    _: Any, _: Sendable, _: Any, _: SendableMetatype,
+    _: AnyKeyPath, _: AnyKeyPath & Sendable, _: AnyKeyPath, _: AnyKeyPath & SendableMetatype,
+    _: Any, _: Sendable & BitwiseCopyable, _: Any, _: SendableMetatype & BitwiseCopyable
   )
 )
-func testMarkerProtocols<A: Sendable, B>(
-  _: A, _: B,
-  _: Sendable, _: Any,
-  _: AnyKeyPath & Sendable, _: AnyKeyPath,
-  _: Sendable & BitwiseCopyable, _: Any
+func testMarkerProtocols<A: Sendable, B, C: SendableMetatype, D>(
+  _: A, _: B, _: C, _: D,
+  _: Sendable, _: Any, _: SendableMetatype, _: Any,
+  _: AnyKeyPath & Sendable, _: AnyKeyPath, _: AnyKeyPath & SendableMetatype, _: AnyKeyPath,
+  _: Sendable & BitwiseCopyable, _: Any, _: SendableMetatype & BitwiseCopyable, _: Any
 ) {}
 
 @abi(
@@ -1232,41 +1233,96 @@ nonisolated func isolation5() {}
 @abi(func isolation7(_: some Actor))
 func isolation7(_: isolated some Actor) {}
 
-@abi(@execution(concurrent) func isolation8() async)
-@execution(concurrent) func isolation8() async {}
+@abi(@concurrent func isolation8() async)
+@concurrent func isolation8() async {}
 
 @abi(func isolation9() async)
-@execution(concurrent) func isolation9() async {}
+@concurrent func isolation9() async {}
 
-@abi(@execution(concurrent) func isolation10() async)
+@abi(@concurrent func isolation10() async)
 func isolation10() async {}
 
 @abi(nonisolated func isolation11() async)
-@execution(concurrent) func isolation11() async {}
+@concurrent func isolation11() async {}
 
-@abi(@execution(concurrent) func isolation12() async)
+@abi(@concurrent func isolation12() async)
 nonisolated func isolation12() async {}
 
-@abi(@execution(caller) func isolation13() async)
-@execution(caller) func isolation13() async {}
+@abi(nonisolated(nonsending) func isolation13() async)
+nonisolated(nonsending) func isolation13() async {}
 
 @abi(func isolation14() async)
-@execution(caller) func isolation14() async {}
+nonisolated(nonsending) func isolation14() async {}
 
-@abi(@execution(caller) func isolation15() async)
+@abi(nonisolated(nonsending) func isolation15() async)
 func isolation15() async {}
 
 @abi(nonisolated func isolation16() async)
-@execution(caller) func isolation16() async {}
+nonisolated(nonsending) func isolation16() async {}
 
-@abi(@execution(caller) func isolation17() async)
+@abi(nonisolated(nonsending) func isolation17() async)
 nonisolated func isolation17() async {}
 
-@abi(@execution(caller) func isolation18() async)
-@execution(concurrent) func isolation18() async {}
+@abi(nonisolated(nonsending) func isolation18() async)
+@concurrent func isolation18() async {}
+
+@abi(@concurrent func isolation19() async)
+nonisolated(nonsending) func isolation19() async {}
+
+// CustomAttr for property wrapper -- banned in and with '@abi'
+// Banned because we would need to design behavior for its auxiliary decls.
+@propertyWrapper struct PropertyWrapper {
+  var wrappedValue: Int { fatalError() }
+}
+
+struct CustomAttrPropertyWrapper {
+  @abi(@PropertyWrapper var v1: Int) // expected-error {{property 'v1' with a wrapper cannot also be '@abi'}}
+  @PropertyWrapper var v1: Int // expected-error {{property 'v1' with a wrapper cannot also be '@abi'}}
+
+  @abi(@PropertyWrapper var v2: Int) // expected-error {{property 'v2' with a wrapper cannot also be '@abi'}}
+  var v2: Int
+
+  @abi(var v3: Int)
+  @PropertyWrapper var v3: Int // expected-error {{property 'v3' with a wrapper cannot also be '@abi'}}
+}
+
+// CustomAttr for attached macro -- see Macros/macro_expand_peers.swift
+// Freestanding macro in @abi -- see Macros/macro_expand.swift
+
+// CustomAttr for result builder -- banned in '@abi'
+// Has no ABI impact on either a parameter or a decl.
+@resultBuilder struct ResultBuilder {
+  static func buildBlock(_ values: Int...) -> Int { values.reduce(0, +) }
+}
+
+struct CustomAttrResultBuilder {
+  @abi(@ResultBuilder var v1: Int) // expected-error {{unused 'ResultBuilder' attribute in '@abi'}} {{8-22=}}
+  @ResultBuilder var v1: Int { 0 }
+
+  @abi(@ResultBuilder var v2: Int) // expected-error {{unused 'ResultBuilder' attribute in '@abi'}} {{8-22=}}
+  var v2: Int { 0 }
+
+  @abi(var v3: Int)
+  @ResultBuilder var v3: Int { 0 }
+
+  @abi(@ResultBuilder func fn11() -> Int) // expected-error {{unused 'ResultBuilder' attribute in '@abi'}} {{8-22=}}
+  @ResultBuilder func fn11() -> Int { 0 }
+
+  @abi(@ResultBuilder func fn21() -> Int) // expected-error {{unused 'ResultBuilder' attribute in '@abi'}} {{8-22=}}
+  func fn21() -> Int { 0 }
 
-@abi(@execution(concurrent) func isolation19() async)
-@execution(caller) func isolation19() async {}
+  @abi(func fn31() -> Int)
+  @ResultBuilder func fn31() -> Int { 0 }
+
+  @abi(func fn12(@ResultBuilder _: () -> Int) -> Int) // expected-error {{unused 'ResultBuilder' attribute in '@abi'}}  {{18-32=}}
+  func fn12(@ResultBuilder _: () -> Int) -> Int { 0 }
+
+  @abi(func fn22(@ResultBuilder _: () -> Int) -> Int) // expected-error {{unused 'ResultBuilder' attribute in '@abi'}} {{18-32=}}
+  func fn22(_: () -> Int) -> Int { 0 }
+
+  @abi(func fn32(_: () -> Int) -> Int)
+  func fn32(@ResultBuilder _: () -> Int) -> Int { 0 }
+}
 
 // NSCopying - see attr/attr_abi_objc.swift
 
@@ -1350,16 +1406,19 @@ func nonEphemeral2(_: UnsafeRawPointer) {}
 @abi(func disfavoredOverload3(_: UnsafeRawPointer))
 func nonEphemeral3(@_nonEphemeral _: UnsafeRawPointer) {}
 
-// @_inheritActorContext -- banned in @abi
-@abi(func inheritActorContext1(@_inheritActorContext fn: @Sendable @escaping () async -> Void)) // expected-error {{unused '_inheritActorContext' attribute in '@abi'}} {{32-53=}}
+// @_inheritActorContext
+@abi(func inheritActorContext1(@_inheritActorContext fn: @Sendable @escaping () async -> Void))
 func inheritActorContext1(@_inheritActorContext fn: @Sendable @escaping () async -> Void) {}
 
-@abi(func inheritActorContext2(@_inheritActorContext fn: @Sendable @escaping () async -> Void)) // expected-error {{unused '_inheritActorContext' attribute in '@abi'}} {{32-53=}}
+@abi(func inheritActorContext2(@_inheritActorContext fn: @Sendable @escaping () async -> Void))
 func inheritActorContext2(fn: @Sendable @escaping () async -> Void) {}
 
 @abi(func inheritActorContext3(fn: @Sendable @escaping () async -> Void))
 func inheritActorContext3(@_inheritActorContext fn: @Sendable @escaping () async -> Void) {}
 
+@abi(func inheritActorContext4(@_inheritActorContext(always) fn: @Sendable @escaping () async -> Void))
+func inheritActorContext4(fn: @Sendable @escaping () async -> Void) {}
+
 // @excusivity(checked/unchecked) -- banned in @abi
 class Exclusivity {
   @abi(var checked00: Int)
@@ -1814,45 +1873,48 @@ func section2() {}
 @abi(func section3())
 @_section("fnord") func section3() {}
 
-// @inlinable -- automatically cloned into @abi
-@abi(@inlinable func inlinable1())
+// @inlinable -- banned in @abi
+// Although the inlining *does* occasionally get mangled, it's only done in the
+// SpecializationManglers, which shouldn't get their serialization from an ABI
+// attribute.
+@abi(@inlinable func inlinable1()) // expected-error {{unused 'inlinable' attribute in '@abi'}} {{6-16=}}
 @inlinable func inlinable1() {}
 
-@abi(@inlinable func inlinable2()) // expected-error {{extra 'inlinable' attribute in '@abi'}} {{6-16=}}
+@abi(@inlinable func inlinable2()) // expected-error {{unused 'inlinable' attribute in '@abi'}} {{6-16=}}
 func inlinable2() {}
 
-@abi(func inlinable3()) // expected-remark {{inferred '@inlinable' in '@abi' to match attribute on API}}
-@inlinable func inlinable3() {} // expected-note {{matches attribute here}}
+@abi(func inlinable3())
+@inlinable func inlinable3() {}
 
-// @inline -- automatically cloned into @abi
-@abi(@inline(never) func inline1())
+// @inlinable -- banned in @abi
+@abi(@inline(never) func inline1()) // expected-error {{unused 'inline(never)' attribute in '@abi'}} {{6-20=}}
 @inline(never) func inline1() {}
 
-@abi(@inline(never) func inline2()) // expected-error {{extra 'inline(never)' attribute in '@abi'}} {{6-20=}}
+@abi(@inline(never) func inline2()) // expected-error {{unused 'inline(never)' attribute in '@abi'}} {{6-20=}}
 func inline2() {}
 
-@abi(func inline3()) // expected-remark {{inferred '@inline(never)' in '@abi' to match attribute on API}}
-@inline(never) func inline3() {} // expected-note {{matches attribute here}}
+@abi(func inline3())
+@inline(never) func inline3() {}
 
-// @_transparent -- automatically cloned into @abi
-@abi(@_transparent func transparent1())
+// @_transparent -- banned in @abi
+@abi(@_transparent func transparent1()) // expected-error {{unused '_transparent' attribute in '@abi'}} {{6-19=}}
 @_transparent func transparent1() {}
 
-@abi(@_transparent func transparent2()) // expected-error {{extra '_transparent' attribute in '@abi'}} {{6-19=}}
+@abi(@_transparent func transparent2()) // expected-error {{unused '_transparent' attribute in '@abi'}} {{6-19=}}
 func transparent2() {}
 
-@abi(func transparent3()) // expected-remark {{inferred '@_transparent' in '@abi' to match attribute on API}}
-@_transparent func transparent3() {} // expected-note {{matches attribute here}}
+@abi(func transparent3())
+@_transparent func transparent3() {}
 
-// @_alwaysEmitIntoClient -- automatically cloned into @abi
-@abi(@_alwaysEmitIntoClient func alwaysEmitIntoClient1())
+// @_alwaysEmitIntoClient -- banned in @abi
+@abi(@_alwaysEmitIntoClient func alwaysEmitIntoClient1()) // expected-error {{unused '_alwaysEmitIntoClient' attribute in '@abi'}} {{6-28=}}
 @_alwaysEmitIntoClient func alwaysEmitIntoClient1() {}
 
-@abi(@_alwaysEmitIntoClient func alwaysEmitIntoClient2()) // expected-error {{extra '_alwaysEmitIntoClient' attribute in '@abi'}} {{6-28=}}
+@abi(@_alwaysEmitIntoClient func alwaysEmitIntoClient2()) // expected-error {{unused '_alwaysEmitIntoClient' attribute in '@abi'}} {{6-28=}}
 func alwaysEmitIntoClient2() {}
 
-@abi(func alwaysEmitIntoClient3()) // expected-remark {{inferred '@_alwaysEmitIntoClient' in '@abi' to match attribute on API}}
-@_alwaysEmitIntoClient func alwaysEmitIntoClient3() {} // expected-note {{matches attribute here}}
+@abi(func alwaysEmitIntoClient3())
+@_alwaysEmitIntoClient func alwaysEmitIntoClient3() {}
 
 // @_optimize(none) -- banned in @abi
 @abi(@_optimize(none) func optimize1()) // expected-error {{unused '_optimize(none)' attribute in '@abi'}} {{6-22=}}
@@ -1892,16 +1954,17 @@ class Required {
   required init(i3: Void) { fatalError() } // expected-note {{should match modifier here}}
 }
 
-// lazy -- automatically cloned into @abi
+// lazy -- banned both in and with @abi
+// This introduces auxiliary decls whose ABI could not be controlled.
 class Lazy {
-  @abi(lazy var v1: Int)
-  lazy var v1: Int = 0
+  @abi(lazy var v1: Int) // expected-error {{'lazy' is not compatible with '@abi' attribute}} {{8-12=}}
+  lazy var v1: Int = 0 // expected-error {{'lazy' is not compatible with '@abi' attribute}} {{3-8=}}
 
-  @abi(lazy var v2: Int) // expected-error {{extra 'lazy' modifier in '@abi'}} {{8-12=}}
+  @abi(lazy var v2: Int) // expected-error {{'lazy' is not compatible with '@abi' attribute}} {{8-12=}}
   var v2: Int = 0
 
-  @abi(var v3: Int) // expected-remark {{inferred 'lazy' in '@abi' to match modifier on API}}
-  lazy var v3: Int = 0 // expected-note {{matches modifier here}}
+  @abi(var v3: Int)
+  lazy var v3: Int = 0 // expected-error {{'lazy' is not compatible with '@abi' attribute}} {{3-8=}}
 }
 
 // @_fixed_layout -- banned in @abi
@@ -1976,34 +2039,34 @@ extension DynamicReplacement {
 
 // @_weakLinked -- tested in attr/attr_weaklinked.swift
 
-// @_borrowed -- automatically cloned into @abi
+// @_borrowed -- banned in @abi
 protocol BorrowedAttr {
-  @abi(@_borrowed var v1: Int)
+  @abi(@_borrowed var v1: Int) // expected-error {{unused '_borrowed' attribute in '@abi'}} {{8-18=}}
   @_borrowed var v1: Int { get set }
 
-  @abi(var v2: Int) // expected-remark {{inferred '@_borrowed' in '@abi' to match attribute on API}}
-  @_borrowed var v2: Int { get set } // expected-note {{matches attribute here}}
+  @abi(var v2: Int)
+  @_borrowed var v2: Int { get set }
 
-  @abi(@_borrowed var v3: Int) // expected-error {{extra '_borrowed' attribute in '@abi'}} {{8-18=}}
+  @abi(@_borrowed var v3: Int) // expected-error {{unused '_borrowed' attribute in '@abi'}} {{8-18=}}
   var v3: Int { get set }
 }
 
-// @lifetime -- must match in @abi
+// @_lifetime -- must match in @abi
 // TODO: Probably possible to make these unconstrained as long as we ensure
 // that `@_addressableForDependencies` doesn't cause a calling convention
 // change.
 struct Lifetime: ~Escapable {
-  @abi(@lifetime(borrow i1) init(i1: UnsafeRawPointer))
-  @lifetime(borrow i1) init(i1: UnsafeRawPointer) {}
+  @abi(@_lifetime(borrow i1) init(i1: UnsafeRawPointer))
+  @_lifetime(borrow i1) init(i1: UnsafeRawPointer) {}
 
-  @abi(@lifetime(borrow i2) init(i2: UnsafeRawPointer)) // expected-error {{extra 'lifetime' attribute in '@abi'}} {{8-28=}}
+  @abi(@_lifetime(borrow i2) init(i2: UnsafeRawPointer)) // expected-error {{extra '_lifetime' attribute in '@abi'}} {{8-29=}}
   init(i2: UnsafeRawPointer) {}
 
-  @abi(init(i3: UnsafeRawPointer)) // expected-error {{missing 'lifetime' attribute in '@abi'}} {{8-8=@lifetime(borrow i3) }}
-  @lifetime(borrow i3) init(i3: UnsafeRawPointer) {} // expected-note {{should match attribute here}}
+  @abi(init(i3: UnsafeRawPointer)) // expected-error {{missing '_lifetime' attribute in '@abi'}} {{8-8=@_lifetime(borrow i3) }}
+  @_lifetime(borrow i3) init(i3: UnsafeRawPointer) {} // expected-note {{should match attribute here}}
 
-  @abi(@lifetime(borrow i4) init(i4: UnsafeRawPointer, i4a: UnsafeRawPointer)) // expected-error {{'lifetime' attribute in '@abi' should match '@lifetime(borrow i4a)'}} {{8-28=@lifetime(borrow i4a)}}
-  @lifetime(borrow i4a) init(i4: UnsafeRawPointer, i4a: UnsafeRawPointer) {} // expected-note {{should match attribute here}}
+  @abi(@_lifetime(borrow i4) init(i4: UnsafeRawPointer, i4a: UnsafeRawPointer)) // expected-error {{'_lifetime' attribute in '@abi' should match '@_lifetime(borrow i4a)'}} {{8-29=@_lifetime(borrow i4a)}}
+  @_lifetime(borrow i4a) init(i4: UnsafeRawPointer, i4a: UnsafeRawPointer) {} // expected-note {{should match attribute here}}
 }
 
 // @_unsafeNonescapableResult -- must match in @abi
diff --git a/test/attr/attr_abi_objc.swift b/test/attr/attr_abi_objc.swift
index 581d1e5ab358a..b16e0ae6c440a 100644
--- a/test/attr/attr_abi_objc.swift
+++ b/test/attr/attr_abi_objc.swift
@@ -1,6 +1,5 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature ABIAttribute -parse-as-library -Rabi-inference
+// RUN: %target-typecheck-verify-swift -parse-as-library
 
-// REQUIRES: swift_feature_ABIAttribute
 // REQUIRES: objc_interop
 
 import Foundation
@@ -21,7 +20,7 @@ struct FutureType {}
 
 @abi(func available5(_: FutureType)) // expected-error {{'FutureType' is only available in }}
 func available5(_: FutureType) {} // expected-error {{'FutureType' is only available in }}
-// expected-note@-1 2{{add @available attribute to enclosing global function}} (fix-it not tested because it varies by target)
+// expected-note@-1 2{{add '@available' attribute to enclosing global function}} (fix-it not tested because it varies by target)
 
 @abi(func available6(_: FutureType))
 @available(macOS 99, iOS 99, tvOS 99, watchOS 99, visionOS 99, *) func available6(_: FutureType) {}
diff --git a/test/attr/attr_autoclosure.swift b/test/attr/attr_autoclosure.swift
index 4e9b0a31a558b..0b31ccc7266fc 100644
--- a/test/attr/attr_autoclosure.swift
+++ b/test/attr/attr_autoclosure.swift
@@ -5,7 +5,7 @@ var fn : @autoclosure () -> Int = 4  // expected-error {{'@autoclosure' may only
 
 @autoclosure func func1() {}  // expected-error {{attribute can only be applied to types, not declarations}}
 
-func func1a(_ v1 : @autoclosure Int) {} // expected-error {{@autoclosure attribute only applies to function types}}
+func func1a(_ v1 : @autoclosure Int) {} // expected-error {{'@autoclosure' only applies to function types}}
 
 
 func func2(_ fp : @autoclosure () -> Int) { func2(4)}
@@ -18,8 +18,8 @@ func func6(_: @autoclosure () -> Int) {func6(0)}
 func func8(_ x: inout @autoclosure () -> Bool) -> Bool {  // expected-error {{'@autoclosure' may only be used on parameters}}
 }
 
-func func9(_ x: @autoclosure (Int) -> Bool) {} // expected-error {{argument type of @autoclosure parameter must be '()'}}
-func func10(_ x: @autoclosure (Int, String, Int) -> Void) {} // expected-error {{argument type of @autoclosure parameter must be '()'}}
+func func9(_ x: @autoclosure (Int) -> Bool) {} // expected-error {{argument type of '@autoclosure' parameter must be '()'}}
+func func10(_ x: @autoclosure (Int, String, Int) -> Void) {} // expected-error {{argument type of '@autoclosure' parameter must be '()'}}
 
 // <rdar://problem/19707366> QoI: @autoclosure declaration change fixit
 let migrate4 : (@autoclosure() -> ()) -> ()
@@ -59,7 +59,7 @@ struct S : P2 {
   func each(_ closure: @autoclosure () -> ()) {
     // expected-note@-1{{parameter 'closure' is implicitly non-escaping}}
 
-    overloadedEach(self, closure) // expected-error {{passing non-escaping parameter 'closure' to function expecting an @escaping closure}}
+    overloadedEach(self, closure) // expected-error {{passing non-escaping parameter 'closure' to function expecting an '@escaping' closure}}
   }
 }
 
@@ -82,7 +82,7 @@ func func12_sink(_ x: @escaping () -> Int) { }
 func func12a(_ x: @autoclosure () -> Int) {
   // expected-note@-1{{parameter 'x' is implicitly non-escaping}}
 
-  func12_sink(x) // expected-error {{passing non-escaping parameter 'x' to function expecting an @escaping closure}}
+  func12_sink(x) // expected-error {{passing non-escaping parameter 'x' to function expecting an '@escaping' closure}}
 }
 func func12c(_ x: @autoclosure @escaping () -> Int) {
   func12_sink(x) // ok
@@ -146,13 +146,13 @@ func variadicAutoclosure(_ fn: @autoclosure () -> ()...) {
 // These are all arguably invalid; the autoclosure should have to be called.
 // But as long as we allow them, we shouldn't crash.
 func passNonThrowingToNonThrowingAC(_ fn: @autoclosure () -> Int) {
-  takesAutoclosure(fn) // expected-error {{add () to forward @autoclosure parameter}} {{22-22=()}}
+  takesAutoclosure(fn) // expected-error {{add () to forward '@autoclosure' parameter}} {{22-22=()}}
 }
 func passNonThrowingToThrowingAC(_ fn: @autoclosure () -> Int) {
-  takesThrowingAutoclosure(fn) // expected-error {{add () to forward @autoclosure parameter}} {{30-30=()}}
+  takesThrowingAutoclosure(fn) // expected-error {{add () to forward '@autoclosure' parameter}} {{30-30=()}}
 }
 func passThrowingToThrowingAC(_ fn: @autoclosure () throws -> Int) {
-  takesThrowingAutoclosure(fn) // expected-error {{add () to forward @autoclosure parameter}} {{30-30=()}}
+  takesThrowingAutoclosure(fn) // expected-error {{add () to forward '@autoclosure' parameter}} {{30-30=()}}
 }
 
 func passAutoClosureToSubscriptAndMember(_ fn: @autoclosure () -> Int) {
@@ -165,9 +165,9 @@ func passAutoClosureToSubscriptAndMember(_ fn: @autoclosure () -> Int) {
   }
 
   let s = S()
-  let _ = s.bar(42, fn) // expected-error {{add () to forward @autoclosure parameter}} {{23-23=()}}
-  let _ = s[fn] // expected-error {{add () to forward @autoclosure parameter}} {{15-15=()}}
-  let _ = S.foo(fn) // expected-error {{add () to forward @autoclosure parameter}} {{19-19=()}}
+  let _ = s.bar(42, fn) // expected-error {{add () to forward '@autoclosure' parameter}} {{23-23=()}}
+  let _ = s[fn] // expected-error {{add () to forward '@autoclosure' parameter}} {{15-15=()}}
+  let _ = S.foo(fn) // expected-error {{add () to forward '@autoclosure' parameter}} {{19-19=()}}
 }
 
 func passAutoClosureToEnumCase(_ fn: @autoclosure () -> Int) {
@@ -176,7 +176,7 @@ func passAutoClosureToEnumCase(_ fn: @autoclosure () -> Int) {
   }
 
   let _: E = .baz(42) // Ok
-  let _: E = .baz(fn) // expected-error {{add () to forward @autoclosure parameter}} {{21-21=()}}
+  let _: E = .baz(fn) // expected-error {{add () to forward '@autoclosure' parameter}} {{21-21=()}}
 }
 
 // rdar://problem/20591571 - Various type inference problems with @autoclosure
@@ -225,14 +225,14 @@ class Foo {
 
 class Bar {
   typealias BarClosure = (String) -> String
-  func barFunction(closure: @autoclosure BarClosure) {} // expected-error {{argument type of @autoclosure parameter must be '()'}}
+  func barFunction(closure: @autoclosure BarClosure) {} // expected-error {{argument type of '@autoclosure' parameter must be '()'}}
 }
 
 func rdar_47586626() {
   struct S {}
   typealias F = () -> S
 
-  func foo(_: @autoclosure S) {} // expected-error {{@autoclosure attribute only applies to function types}}
+  func foo(_: @autoclosure S) {} // expected-error {{'@autoclosure' only applies to function types}}
   func bar(_: @autoclosure F) {} // Ok
 
   let s = S()
@@ -258,7 +258,7 @@ func autoclosure_param_returning_func_type() {
 
   func bar_1(_ fn: @autoclosure @escaping () -> Int) { foo(fn) } // Ok
   func bar_2(_ fn: @autoclosure () -> Int) { foo(fn) } // expected-note {{parameter 'fn' is implicitly non-escaping}}
-  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  // expected-error@-1 {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
   func baz_1(_ fn: @autoclosure @escaping () -> Int) { generic_foo(fn) }   // Ok (T is inferred as () -> Int)
   func baz_2(_ fn: @autoclosure @escaping () -> Int) { generic_foo(fn()) } // Ok (T is inferred as Int)
   func baz_3(_ fn: @autoclosure () -> Int) { generic_foo(fn) } // Fails because fn is not marked as @escaping
@@ -268,14 +268,14 @@ func autoclosure_param_returning_func_type() {
   func biz_1(_ fn: @autoclosure @escaping () -> Int) { overloaded_autoclj(fn) }   // Ok
   func biz_2(_ fn: @autoclosure @escaping () -> Int) { overloaded_autoclj(fn()) } // Ok
   func biz_3(_ fn: @autoclosure () -> Int) { overloaded_autoclj(fn) } // Fails because fn is not marked as @escaping
-  // expected-error@-1 {{add () to forward @autoclosure parameter}} {{67-67=()}}
+  // expected-error@-1 {{add () to forward '@autoclosure' parameter}} {{67-67=()}}
 
   func fiz(_: @autoclosure () -> (() -> Int)) {}
 
   func biz_4(_ fn: @autoclosure @escaping () -> (() -> Int)) { fiz(fn) } // Can't forward in Swift >= 5 mode
-  // expected-error@-1 {{add () to forward @autoclosure parameter}} {{70-70=()}}
+  // expected-error@-1 {{add () to forward '@autoclosure' parameter}} {{70-70=()}}
   func biz_5(_ fn: @escaping () -> (() -> Int)) { fiz(fn) } // Can't forward in Swift >= 5 mode
-  // expected-error@-1 {{add () to forward @autoclosure parameter}} {{57-57=()}}
+  // expected-error@-1 {{add () to forward '@autoclosure' parameter}} {{57-57=()}}
 }
 
 func test_autoclosure_with_generic_argument_mismatch() {
@@ -300,7 +300,7 @@ struct S_54357 : @autoclosure P_54357 {} // expected-error {{'@autoclosure' may
 
 // https://github.com/apple/swift/issues/51669
 
-func f_51669<T>(_ x: @autoclosure T) {} // expected-error 1{{@autoclosure attribute only applies to function types}}
+func f_51669<T>(_ x: @autoclosure T) {} // expected-error 1{{'@autoclosure' only applies to function types}}
 
 func test_autoclosure_type_in_parens() {
   let _: (@autoclosure (() -> Void)) -> Void = { _ in } // Ok
diff --git a/test/attr/attr_availability_async_rename.swift b/test/attr/attr_availability_async_rename.swift
index 21b30ed962a25..2d2526423e350 100644
--- a/test/attr/attr_availability_async_rename.swift
+++ b/test/attr/attr_availability_async_rename.swift
@@ -1,8 +1,8 @@
 // REQUIRES: concurrency
 // REQUIRES: objc_interop
 
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs/custom-modules
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -parse-as-library -I %S/Inputs/custom-modules
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -I %S/Inputs/custom-modules
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -parse-as-library -I %S/Inputs/custom-modules
 
 import ObjcAsync
 
diff --git a/test/attr/attr_availability_canonical_macos_version.swift b/test/attr/attr_availability_canonical_macos_version.swift
index 10cf92286e255..1fadb1e045558 100644
--- a/test/attr/attr_availability_canonical_macos_version.swift
+++ b/test/attr/attr_availability_canonical_macos_version.swift
@@ -1,4 +1,4 @@
-// RUN: %swift -typecheck -verify -parse-stdlib -module-name Swift -target x86_64-apple-macosx11.0 %s
+// RUN: %swift -typecheck -verify -parse-stdlib -module-name Swift -target %target-cpu-apple-macosx26.0 %s
 
 
 @available(OSX, introduced: 10.5, deprecated: 10.8, obsoleted: 11.0,
@@ -16,6 +16,19 @@ func obsoletedIn10_16() { }
 
 obsoletedIn10_16() // expected-error{{'obsoletedIn10_16()' is unavailable in macOS: you don't want to do that anyway}}
 
+@available(OSX, introduced: 10.5, deprecated: 10.8, obsoleted: 16.0,
+              message: "you don't want to do that anyway")
+func obsoletedIn16() { }
+// expected-note @-1{{'obsoletedIn16()' was obsoleted in macOS 26.0}}
+
+obsoletedIn16() // expected-error{{'obsoletedIn16()' is unavailable in macOS: you don't want to do that anyway}}
+
+@available(OSX, introduced: 10.5, deprecated: 10.8, obsoleted: 26.0,
+              message: "you don't want to do that anyway")
+func obsoletedIn26() { }
+// expected-note @-1{{'obsoletedIn26()' was obsoleted in macOS 26.0}}
+
+obsoletedIn26() // expected-error{{'obsoletedIn26()' is unavailable in macOS: you don't want to do that anyway}}
 
 @available(OSX, deprecated: 10.16)
 func deprecatedIn10_16() { }
@@ -26,8 +39,14 @@ func deprecatedIn10_18() { }
 @available(OSX, deprecated: 11.0)
 func deprecatedIn11_0() { }
 
-@available(OSX, deprecated: 13.0)
-func deprecatedIn13_0() { }
+@available(OSX, deprecated: 16.0)
+func deprecatedIn16_0() { }
+
+@available(OSX, deprecated: 26.0)
+func deprecatedIn26_0() { }
+
+@available(OSX, deprecated: 27.0)
+func deprecatedIn27_0() { }
 
 @available(OSXApplicationExtension, deprecated: 10.16)
 func deprecatedIn10_16AppExtension() { }
@@ -36,6 +55,9 @@ func useDeprecated() {
   deprecatedIn10_16() // expected-warning {{deprecatedIn10_16()' was deprecated in macOS 11.0}}
   deprecatedIn10_18() // expected-warning {{'deprecatedIn10_18()' was deprecated in macOS 10.18}}
   deprecatedIn11_0() // expected-warning {{'deprecatedIn11_0()' was deprecated in macOS 11.0}}
+  deprecatedIn16_0() // expected-warning {{'deprecatedIn16_0()' was deprecated in macOS 26.0}}
+  deprecatedIn26_0() // expected-warning {{'deprecatedIn26_0()' was deprecated in macOS 26.0}}
 
-  deprecatedIn13_0()  // no-warning
+  deprecatedIn27_0()
+  deprecatedIn10_16AppExtension()
 }
diff --git a/test/attr/attr_availability_canonical_macos_version_introduction.swift b/test/attr/attr_availability_canonical_macos_version_introduction.swift
index 69409ec882144..0cebd00d7c6f4 100644
--- a/test/attr/attr_availability_canonical_macos_version_introduction.swift
+++ b/test/attr/attr_availability_canonical_macos_version_introduction.swift
@@ -1,4 +1,4 @@
-// RUN: %swift -typecheck -verify -parse-stdlib -module-name Swift -target x86_64-apple-macosx10.15 %s
+// RUN: %swift -typecheck -verify -parse-stdlib -module-name Swift -target %target-cpu-apple-macosx10.15 %s
 
 @available(OSX, introduced: 10.16)
 func longFormIntroducedIn10_16() { }
@@ -12,7 +12,13 @@ func longFormIntroducedIn11_0() { }
 @available(OSX, introduced: 13.0)
 func longFormIntroducedIn13_0() { }
 
-// expected-note@+1 *{{add @available attribute to enclosing global function}}
+@available(OSX, introduced: 16.0)
+func longFormIntroducedIn16_0() { }
+
+@available(OSX, introduced: 26.0)
+func longFormIntroducedIn26_0() { }
+
+// expected-note@+1 *{{add '@available' attribute to enclosing global function}}
 func useLongFromIntroduced() {
   longFormIntroducedIn10_16()
   // expected-error@-1{{'longFormIntroducedIn10_16()' is only available in macOS 11.0 or newer}}
@@ -29,6 +35,14 @@ func useLongFromIntroduced() {
   longFormIntroducedIn13_0()
     // expected-error@-1{{'longFormIntroducedIn13_0()' is only available in macOS 13.0 or newer}}
     // expected-note@-2{{add 'if #available' version check}}
+
+  longFormIntroducedIn16_0()
+  // expected-error@-1{{'longFormIntroducedIn16_0()' is only available in macOS 26.0 or newer}}
+  // expected-note@-2{{add 'if #available' version check}}
+
+  longFormIntroducedIn26_0()
+  // expected-error@-1{{'longFormIntroducedIn26_0()' is only available in macOS 26.0 or newer}}
+  // expected-note@-2{{add 'if #available' version check}}
 }
 
 @available(OSX 10.16, *)
@@ -43,7 +57,13 @@ func shortFormIntroducedIn11_0() { }
 @available(OSX 13.0, *)
 func shortFormIntroducedIn13_0() { }
 
-// expected-note@+1 *{{add @available attribute to enclosing global function}}
+@available(OSX 16.0, *)
+func shortFormIntroducedIn16_0() { }
+
+@available(OSX 26.0, *)
+func shortFormIntroducedIn26_0() { }
+
+// expected-note@+1 *{{add '@available' attribute to enclosing global function}}
 func useShortIntroduced() {
   shortFormIntroducedIn10_16()
     // expected-error@-1{{'shortFormIntroducedIn10_16()' is only available in macOS 11.0 or newer}}
@@ -58,4 +78,12 @@ func useShortIntroduced() {
   shortFormIntroducedIn13_0()
     // expected-error@-1{{'shortFormIntroducedIn13_0()' is only available in macOS 13.0 or newer}}
     // expected-note@-2{{add 'if #available' version check}}
+
+  shortFormIntroducedIn16_0()
+    // expected-error@-1{{'shortFormIntroducedIn16_0()' is only available in macOS 26.0 or newer}}
+    // expected-note@-2{{add 'if #available' version check}}
+
+  shortFormIntroducedIn26_0()
+    // expected-error@-1{{'shortFormIntroducedIn26_0()' is only available in macOS 26.0 or newer}}
+    // expected-note@-2{{add 'if #available' version check}}
 }
diff --git a/test/attr/attr_availability_canonical_macos_version_introduction_appext.swift b/test/attr/attr_availability_canonical_macos_version_introduction_appext.swift
index fa4ff5ad960f0..cf0011e5769a5 100644
--- a/test/attr/attr_availability_canonical_macos_version_introduction_appext.swift
+++ b/test/attr/attr_availability_canonical_macos_version_introduction_appext.swift
@@ -1,9 +1,17 @@
-// RUN: %swift -typecheck -verify -parse-stdlib -module-name Swift -target x86_64-apple-macosx10.15 %s -application-extension
+// RUN: %swift -typecheck -verify -parse-stdlib -module-name Swift -target %target-cpu-apple-macosx10.15 %s -application-extension
 
 @available(OSXApplicationExtension 11, *)
 func introducedInAppExtension11_0() { }
 
 @available(OSXApplicationExtension 10.16, *)
-func useAppExtension() {
+func useAppExtension10_16() {
   introducedInAppExtension11_0() // no-warning
 }
+
+@available(OSXApplicationExtension 26, *)
+func introducedInAppExtension26_0() { }
+
+@available(OSXApplicationExtension 16, *)
+func useAppExtension16_0() {
+  introducedInAppExtension26_0() // no-warning
+}
diff --git a/test/attr/attr_availability_custom_domains.swift b/test/attr/attr_availability_custom_domains.swift
index 4dba8063eec3e..5e0ff387a64f7 100644
--- a/test/attr/attr_availability_custom_domains.swift
+++ b/test/attr/attr_availability_custom_domains.swift
@@ -1,6 +1,7 @@
 // RUN: %target-typecheck-verify-swift \
 // RUN:  -enable-experimental-feature CustomAvailability \
 // RUN:  -define-enabled-availability-domain EnabledDomain \
+// RUN:  -define-always-enabled-availability-domain AlwaysEnabledDomain \
 // RUN:  -define-enabled-availability-domain RedefinedDomain \
 // RUN:  -define-disabled-availability-domain DisabledDomain \
 // RUN:  -define-dynamic-availability-domain DynamicDomain \
@@ -22,6 +23,9 @@ func availableInEnabledDomainWithWildcard() { }
 @available(EnabledDomain, introduced: 1.0) // expected-error {{unexpected version number for EnabledDomain}}
 func introducedInEnabledDomain() { }
 
+@available(AlwaysEnabledDomain, introduced: 1.0) // expected-error {{unexpected version number for AlwaysEnabledDomain}}
+func introducedInAlwaysEnabledDomain() { }
+
 @available(EnabledDomain 1.0) // expected-error {{unexpected version number for EnabledDomain}}
 func introducedInEnabledDomainShort() { }
 
@@ -31,6 +35,9 @@ func introducedInEnabledDomainShortWithWildcard() { }
 @available(macOS 10.10, EnabledDomain, *) // expected-error {{EnabledDomain availability must be specified alone}}
 func introducedInMacOSAndAvailableInEnabledDomain() { }
 
+@available(macOS 10.10, AlwaysEnabledDomain, *) // expected-error {{AlwaysEnabledDomain availability must be specified alone}}
+func introducedInMacOSAndAvailableInAlwaysEnabledDomain() { }
+
 @available(EnabledDomain, macOS 10.10, *) // expected-error {{expected 'available' option such as 'unavailable', 'introduced', 'deprecated', 'obsoleted', 'message', or 'renamed'}}
 // expected-error@-1 {{expected declaration}}
 func availableInEnabledDomainAndIntroducedInMacOS() { }
@@ -57,5 +64,13 @@ func deprecatedInRedefinedDomain() { }
 @available(DynamicDomain)
 func availableInDynamicDomain() { }
 
-@available(UnknownDomain) // expected-warning {{unrecognized platform name 'UnknownDomain'}}
+@available(UnknownDomain) // expected-error {{unrecognized platform name 'UnknownDomain'}}
 func availableInUnknownDomain() { }
+
+@available(EnabledDomain)
+@available(EnabledDomain)
+func availableInEnabledDomainTwice() { }
+
+@available(EnabledDomain)
+@available(EnabledDomain, unavailable)
+func availableAndUnavailableInEnabledDomain() { }
diff --git a/test/attr/attr_availability_invalid_platform_versions.swift b/test/attr/attr_availability_invalid_platform_versions.swift
new file mode 100644
index 0000000000000..8ddb3ce1ac4be
--- /dev/null
+++ b/test/attr/attr_availability_invalid_platform_versions.swift
@@ -0,0 +1,34 @@
+// RUN: %target-swift-frontend -typecheck -verify -parse-stdlib -module-name Swift %s
+
+@available(macOS, introduced: 17) // expected-warning {{'17' is not a valid version number for macOS}}
+@available(iOS, introduced: 20) // expected-warning {{'20' is not a valid version number for iOS}}
+@available(macCatalyst, introduced: 20) // expected-warning {{'20' is not a valid version number for Mac Catalyst}}
+@available(watchOS, introduced: 13) // expected-warning {{'13' is not a valid version number for watchOS}}
+@available(tvOS, introduced: 20) // expected-warning {{'20' is not a valid version number for tvOS}}
+@available(visionOS, introduced: 4) // expected-warning {{'4' is not a valid version number for visionOS}}
+func invalidIntroduced() { }
+
+@available(macOS, deprecated: 17) // expected-warning {{'17' is not a valid version number for macOS}}
+@available(iOS, deprecated: 20) // expected-warning {{'20' is not a valid version number for iOS}}
+@available(macCatalyst, deprecated: 20) // expected-warning {{'20' is not a valid version number for Mac Catalyst}}
+@available(watchOS, deprecated: 13) // expected-warning {{'13' is not a valid version number for watchOS}}
+@available(tvOS, deprecated: 20) // expected-warning {{'20' is not a valid version number for tvOS}}
+@available(visionOS, deprecated: 4) // expected-warning {{'4' is not a valid version number for visionOS}}
+func invalidDeprecated() { }
+
+@available(macOS, obsoleted: 17) // expected-warning {{'17' is not a valid version number for macOS}}
+@available(iOS, obsoleted: 20) // expected-warning {{'20' is not a valid version number for iOS}}
+@available(macCatalyst, obsoleted: 20) // expected-warning {{'20' is not a valid version number for Mac Catalyst}}
+@available(watchOS, obsoleted: 13) // expected-warning {{'13' is not a valid version number for watchOS}}
+@available(tvOS, obsoleted: 20) // expected-warning {{'20' is not a valid version number for tvOS}}
+@available(visionOS, obsoleted: 4) // expected-warning {{'4' is not a valid version number for visionOS}}
+func invalidObsoleted() { }
+
+@available(macOS 18, iOS 21, macCatalyst 22, watchOS 14, tvOS 23, visionOS 7, *)
+// expected-warning@-1 {{'18' is not a valid version number for macOS}}
+// expected-warning@-2 {{'21' is not a valid version number for iOS}}
+// expected-warning@-3 {{'22' is not a valid version number for Mac Catalyst}}
+// expected-warning@-4 {{'14' is not a valid version number for watchOS}}
+// expected-warning@-5 {{'23' is not a valid version number for tvOS}}
+// expected-warning@-6 {{'7' is not a valid version number for visionOS}}
+func invalidIntroducedShort() { }
diff --git a/test/attr/attr_availability_ios_to_visionos_decl_remap.swift b/test/attr/attr_availability_ios_to_visionos_decl_remap.swift
new file mode 100644
index 0000000000000..7fcc38d1e3190
--- /dev/null
+++ b/test/attr/attr_availability_ios_to_visionos_decl_remap.swift
@@ -0,0 +1,106 @@
+// RUN: %empty-directory(%t/mock-sdk)
+// RUN: cp %S/../Inputs/MockPlatformRemapSDKConfig/SDKSettings.json %t/mock-sdk/SDKSettings.json
+// RUN: %swift -typecheck -verify -parse-stdlib -target arm64-apple-xros1.0 %s -sdk %t/mock-sdk
+
+@available(iOS 17.4, *)
+public func doSomething() { }
+
+@available(iOS 99.0, *)
+public func doSomethingFarFuture() { }
+
+@available(iOS, introduced: 16.0, obsoleted: 17.0, message: "you don't want to do that anyway")
+public func doSomethingElse() { }
+// expected-note@-1 3 {{'doSomethingElse()' was obsoleted in visionOS 1.0}}
+
+@available(iOS, introduced: 16.0, deprecated: 17.0, message: "please don't")
+public func doSomethingInadvisable() { }
+
+@available(iOS 17.0, *)
+public func doSomethingGood() { }
+
+@available(iOS 13.0, *)
+public func doSomethingOld() { }
+
+public func takesSomeProto(_ p: some SomeProto) { }
+
+public protocol SomeProto { }
+
+public struct ConformsToProtoIniOS17_4 { }
+
+@available(iOS 17.4, *)
+extension ConformsToProtoIniOS17_4: SomeProto { }
+
+public struct ConformsToProtoIniOS99 { }
+
+@available(iOS 99, *)
+extension ConformsToProtoIniOS99: SomeProto { }
+
+public struct ConformsToProtoDeprecatedIniOS17 { }
+
+@available(iOS, introduced: 16.0, deprecated: 17.0, message: "please don't")
+extension ConformsToProtoDeprecatedIniOS17: SomeProto { }
+
+public struct ConformsToProtoObsoletedIniOS17 { }
+
+@available(iOS, introduced: 16.0, obsoleted: 17.0, message: "you don't want to do that anyway")
+extension ConformsToProtoObsoletedIniOS17: SomeProto { }
+// expected-note@-1 {{conformance of 'ConformsToProtoObsoletedIniOS17' to 'SomeProto' was obsoleted in visionOS 1.0}}
+
+
+func testDeploymentTarget() {
+  // expected-note@-1 6 {{add '@available' attribute to enclosing global function}}
+  doSomething() // expected-error {{'doSomething()' is only available in visionOS 1.1 or newer}}
+  // expected-note@-1 {{add 'if #available' version check}}{{3-16=if #available(visionOS 1.1, *) {\n      doSomething()\n  \} else {\n      // Fallback on earlier versions\n  \}}}
+  doSomethingFarFuture() // expected-error {{'doSomethingFarFuture()' is only available in iOS 99.0 or newer}}
+  // expected-note@-1 {{add 'if #available' version check}}{{3-25=if #available(iOS 99.0, *) {\n      doSomethingFarFuture()\n  \} else {\n      // Fallback on earlier versions\n  \}}}
+  doSomethingElse() // expected-error{{'doSomethingElse()' is unavailable in visionOS: you don't want to do that anyway}}
+  doSomethingInadvisable() // expected-warning {{'doSomethingInadvisable()' was deprecated in iOS 1.0: please don't}}
+  doSomethingGood()
+  doSomethingOld()
+
+  takesSomeProto(ConformsToProtoIniOS17_4()) // expected-warning {{conformance of 'ConformsToProtoIniOS17_4' to 'SomeProto' is only available in visionOS 1.1 or newer; this is an error in the Swift 6 language mode}}
+  // expected-note@-1 {{add 'if #available' version check}}{{3-45=if #available(visionOS 1.1, *) {\n      takesSomeProto(ConformsToProtoIniOS17_4())\n  \} else {\n      // Fallback on earlier versions\n  \}}}
+  takesSomeProto(ConformsToProtoIniOS99()) // expected-warning {{conformance of 'ConformsToProtoIniOS99' to 'SomeProto' is only available in iOS 99 or newer; this is an error in the Swift 6 language mode}}
+  // expected-note@-1 {{add 'if #available' version check}}{{3-43=if #available(iOS 99, *) {\n      takesSomeProto(ConformsToProtoIniOS99())\n  \} else {\n      // Fallback on earlier versions\n  \}}}
+  takesSomeProto(ConformsToProtoDeprecatedIniOS17()) // expected-warning {{conformance of 'ConformsToProtoDeprecatedIniOS17' to 'SomeProto' was deprecated in iOS 1.0: please don't}}
+  takesSomeProto(ConformsToProtoObsoletedIniOS17()) // expected-error {{conformance of 'ConformsToProtoObsoletedIniOS17' to 'SomeProto' is unavailable in visionOS: you don't want to do that anyway}}
+
+  if #available(iOS 17.4, *) {
+    // #available(iOS ...) is not matched when compiling for visionOS
+    doSomething() // expected-error {{'doSomething()' is only available in visionOS 1.1 or newer}}
+    // expected-note@-1 {{add 'if #available' version check}}{{5-18=if #available(visionOS 1.1, *) {\n        doSomething()\n    \} else {\n        // Fallback on earlier versions\n    \}}}
+
+    takesSomeProto(ConformsToProtoIniOS17_4()) // expected-warning {{conformance of 'ConformsToProtoIniOS17_4' to 'SomeProto' is only available in visionOS 1.1 or newer; this is an error in the Swift 6 language mode}}
+    // expected-note@-1 {{add 'if #available' version check}}{{5-47=if #available(visionOS 1.1, *) {\n        takesSomeProto(ConformsToProtoIniOS17_4())\n    \} else {\n        // Fallback on earlier versions\n    \}}}
+
+    if #available(iOS 17.1, *) { }
+  }
+
+  if #available(visionOS 2.0, *) {
+    doSomething()
+  }
+}
+
+@available(iOS 17.4, *)
+func testAfterDeployment_iOS() {
+  doSomething()
+  doSomethingElse() // expected-error {{'doSomethingElse()' is unavailable in visionOS: you don't want to do that anyway}}
+  doSomethingFarFuture() // expected-error {{'doSomethingFarFuture()' is only available in iOS 99.0 or newer}}
+  // expected-note@-1 {{add 'if #available' version check}}
+  doSomethingInadvisable() // expected-warning {{'doSomethingInadvisable()' was deprecated in iOS 1.0: please don't}}
+  doSomethingGood()
+  doSomethingOld()
+
+  takesSomeProto(ConformsToProtoIniOS17_4())
+}
+
+@available(visionOS 2.0, *)
+func testAfterDeployment_visionOS() {
+  doSomething()
+  doSomethingElse() // expected-error{{'doSomethingElse()' is unavailable in visionOS: you don't want to do that anyway}}
+  doSomethingInadvisable() // expected-warning {{'doSomethingInadvisable()' was deprecated in iOS 1.0: please don't}}
+  doSomethingGood()
+  doSomethingOld()
+
+  takesSomeProto(ConformsToProtoIniOS17_4())
+}
diff --git a/test/attr/attr_availability_maccatalyst.swift b/test/attr/attr_availability_maccatalyst.swift
index 61bd6004ed620..5f70030a0f8ca 100644
--- a/test/attr/attr_availability_maccatalyst.swift
+++ b/test/attr/attr_availability_maccatalyst.swift
@@ -52,7 +52,7 @@ func introducedLaterOnMacCatalyst() {
 func introducedLaterOnIOS() {
 }
 
-// expected-note@+1 *{{add @available attribute to enclosing global function}}
+// expected-note@+1 *{{add '@available' attribute to enclosing global function}}
 func testPoundAvailable() {
 
   if #available(macCatalyst 55.0, *) {
diff --git a/test/attr/attr_availability_narrow.swift b/test/attr/attr_availability_narrow.swift
index 2847a5aa5f08c..8058828abc57c 100644
--- a/test/attr/attr_availability_narrow.swift
+++ b/test/attr/attr_availability_narrow.swift
@@ -32,7 +32,7 @@ func useFooUnaffectedSimilarText() {
 }
 
 func useFooWayOff() {
-  // expected-note@-1 2 {{add @available attribute to enclosing global function}}
+  // expected-note@-1 2 {{add '@available' attribute to enclosing global function}}
   if #available(OSX 10.10, *) {
     foo() // expected-error {{'foo()' is only available in macOS 50.2 or newer}}
     // expected-note@-1{{add 'if #available' version check}}
@@ -83,7 +83,7 @@ func useFoo10() {
 }
 
 func useFoo10WayOff() {
-    // expected-note@-1 3 {{add @available attribute to enclosing global function}}
+    // expected-note@-1 3 {{add '@available' attribute to enclosing global function}}
   if #available(OSX 10.10, *) {
     foo10() // expected-error {{'foo10()' is only available in macOS 10.50.2 or newer}}
     // expected-note@-1{{add 'if #available' version check}}
diff --git a/test/attr/attr_availability_osx.swift b/test/attr/attr_availability_osx.swift
index a87bf8d0dbe40..52de11e075763 100644
--- a/test/attr/attr_availability_osx.swift
+++ b/test/attr/attr_availability_osx.swift
@@ -195,8 +195,8 @@ extension TestStruct {
   }
 }
 
-extension TestStruct { // expected-note{{add @available attribute to enclosing extension}}
-  func availableFuncMacOS() { // expected-note{{add @available attribute to enclosing instance method}}
+extension TestStruct { // expected-note{{add '@available' attribute to enclosing extension}}
+  func availableFuncMacOS() { // expected-note{{add '@available' attribute to enclosing instance method}}
     introducedInExtensionMacOS() // expected-error {{'introducedInExtensionMacOS()' is only available in macOS 50 or newer}}
     // expected-note@-1{{add 'if #available' version check}}
   }
diff --git a/test/attr/attr_availability_swift.swift b/test/attr/attr_availability_swift.swift
deleted file mode 100644
index d8c4db269ac50..0000000000000
--- a/test/attr/attr_availability_swift.swift
+++ /dev/null
@@ -1,67 +0,0 @@
-// RUN: %target-typecheck-verify-swift
-
-@available(swift 3.0)
-func foo() {
-}
-
-@available(swift 3.0, *) // expected-error {{Swift version availability must be specified alone}}
-func foo2() {
-}
-
-@available(swift 3.0, iOS 10, *) // expected-error {{Swift version availability must be specified alone}}
-func bar() {
-}
-
-@available(iOS 10, swift 3.0, *) // expected-error {{Swift version availability must be specified alone}}
-func bar2() {
-}
-
-@available(iOS 10, *, swift 3.0) // expected-error {{Swift version availability must be specified alone}}
-func bar3() {
-}
-
-func baz() {
-  if #available(swift 4) { // expected-error {{Swift version checks not allowed in #available}}
-                           // expected-error @-1 {{condition required for target platform}}
-    print("yes")
-  } else {
-    print("no")
-  }
-
-  if #unavailable(swift 4) { // expected-error {{Swift version checks not allowed in #unavailable}}
-    print("no")
-  } else {
-    print("yes")
-  }
-}
-
-@available(swift, introduced: 3.0.1, obsoleted: 3.0.2, message: "tiny bug")
-func bug() {
-}
-
-struct TestStruct {}
-
-@available(macOS 10.11, *)
-extension TestStruct {
-  @available(swift 400)
-  func doTheThing() {} // expected-note {{'doTheThing()' was introduced in Swift 400}}
-}
-
-@available(swift 400)
-extension TestStruct {
-  func doAnotherThing() {} // expected-note {{'doAnotherThing()' was introduced in Swift 400}}
-}
-
-@available(macOS 10.11, *)
-func testMemberAvailability() {
-  TestStruct().doTheThing() // expected-error {{'doTheThing()' is unavailable}}
-  TestStruct().doAnotherThing() // expected-error {{'doAnotherThing()' is unavailable}}
-}
-
-@available(swift 400) // FIXME: This has no effect and should be complained about.
-@available(macOS 10.11, *)
-extension TestStruct {}
-
-@available(macOS 10.11, *)
-@available(swift 400) // FIXME: This has no effect and should be complained about.
-extension TestStruct {}
diff --git a/test/attr/attr_availability_swift_language_mode.swift b/test/attr/attr_availability_swift_language_mode.swift
new file mode 100644
index 0000000000000..bf3285bb13495
--- /dev/null
+++ b/test/attr/attr_availability_swift_language_mode.swift
@@ -0,0 +1,70 @@
+// RUN: %target-typecheck-verify-swift
+
+@available(swift 3.0)
+func foo() {
+}
+
+@available(swift 3.0, *) // expected-error {{Swift version availability must be specified alone}}
+func foo2() {
+}
+
+@available(swift 3.0, iOS 10, *) // expected-error {{Swift version availability must be specified alone}}
+func bar() {
+}
+
+@available(iOS 10, swift 3.0, *) // expected-error {{Swift version availability must be specified alone}}
+func bar2() {
+}
+
+@available(iOS 10, *, swift 3.0) // expected-error {{Swift version availability must be specified alone}}
+func bar3() {
+}
+
+func baz() {
+  if #available(swift 4) { // expected-error {{Swift version checks not allowed in #available}}
+                           // expected-error @-1 {{condition required for target platform}}
+    print("yes")
+  } else {
+    print("no")
+  }
+
+  if #unavailable(swift 4) { // expected-error {{Swift version checks not allowed in #unavailable}}
+    print("no")
+  } else {
+    print("yes")
+  }
+}
+
+@available(swift, introduced: 3.0.1, obsoleted: 3.0.2, message: "tiny bug")
+func bug() {
+}
+
+struct TestStruct {}
+
+@available(macOS 10.11, *)
+extension TestStruct {
+  @available(swift 400)
+  func doTheThing() {} // expected-note {{'doTheThing()' was introduced in Swift 400}}
+}
+
+@available(swift 400)
+extension TestStruct {
+  func doAnotherThing() {} // expected-note {{'doAnotherThing()' was introduced in Swift 400}}
+}
+
+@available(macOS 10.11, *)
+func testMemberAvailability() {
+  TestStruct().doTheThing() // expected-error {{'doTheThing()' is unavailable}}
+  TestStruct().doAnotherThing() // expected-error {{'doAnotherThing()' is unavailable}}
+}
+
+@available(swift 400)
+@available(macOS 10.11, *)
+extension TestStruct {}
+
+@available(macOS 10.11, *)
+@available(swift 400)
+extension TestStruct {}
+
+@available(SwiftLanguageMode 400) // expected-error {{Swift requires '-enable-experimental-feature SwiftRuntimeAvailability'}}
+extension TestStruct {}
diff --git a/test/attr/attr_availability_swift_runtime.swift b/test/attr/attr_availability_swift_runtime.swift
new file mode 100644
index 0000000000000..81eb35ba71e18
--- /dev/null
+++ b/test/attr/attr_availability_swift_runtime.swift
@@ -0,0 +1,48 @@
+// RUN: %target-typecheck-verify-swift -swift-version 5 -parse-as-library -enable-experimental-feature SwiftRuntimeAvailability
+
+// REQUIRES: swift_feature_SwiftRuntimeAvailability
+
+@available(Swift 6, *)
+func availableInSwiftRuntime6Short() { }
+
+@available(Swift 6.0, *)
+func availableInSwiftRuntime6_0Short() { }
+
+@available(Swift 6, macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+func availableInSwiftRuntime6ShortWithPlatforms() { }
+
+@available(Swift, introduced: 6)
+func availableInSwiftRuntime6() { }
+
+@available(Swift, introduced: 6.0)
+func availableInSwiftRuntime6_0() { }
+
+@available(Swift, introduced: 5.1, obsoleted: 6)
+func availableInSwiftRuntime5_1Thru6() { }
+
+@available(Swift, deprecated: 5.9)
+func deprecatedInSwiftRuntime5_9() { }
+
+@available(Swift 4, *) // expected-warning {{'4' is not a valid version number for Swift}}
+func availableInSwiftRuntime4() { }
+
+@available(Swift 4.9, *) // expected-warning {{'4.9' is not a valid version number for Swift}}
+func availableInSwiftRuntime4_9() { }
+
+// Swift 5.0 is the earliest possible runtime version
+@available(Swift 5, *)
+func availableInSwiftRuntime5() { }
+
+@available(Swift, unavailable) // expected-warning {{'unavailable' cannot be used in '@available' attribute for Swift}}
+func unavailableInSwiftRuntime() { }
+
+// MARK: Swift language mode
+
+@available(swift 6) // expected-warning {{'swift' has been renamed to 'SwiftLanguageMode'}}{{12-17=SwiftLanguageMode}}
+func swift6OldSpellingShort() { }
+
+@available(swift, introduced: 6) // expected-warning {{'swift' has been renamed to 'SwiftLanguageMode'}}{{12-17=SwiftLanguageMode}}
+func swift6OldSpelling() { }
+
+@available(SwiftLanguageMode 6)
+func swiftLanguageModeShort6() { }
diff --git a/test/attr/attr_availability_transitive.swift b/test/attr/attr_availability_transitive.swift
index d01f5268b3cdc..8486bfd139339 100644
--- a/test/attr/attr_availability_transitive.swift
+++ b/test/attr/attr_availability_transitive.swift
@@ -27,18 +27,18 @@ func never() -> NeverAvailable { // expected-note * {{'never()' has been explici
 @available(swift, obsoleted: 4)
 @discardableResult
 func unavailableInSwift4() -> UnavailableInSwift4 { // expected-note * {{'unavailableInSwift4()' was obsoleted in Swift 4}}
-  UnavailableInSwift4() // expected-error {{'UnavailableInSwift4' is unavailable}}
+  UnavailableInSwift4()
 }
 
 @available(swift, introduced: 99)
 @discardableResult
 func availableInFutureSwift() -> AvailableInFutureSwift { // expected-note * {{'availableInFutureSwift()' was introduced in Swift 99}}
-  AvailableInFutureSwift() // expected-error {{'AvailableInFutureSwift' is unavailable}}
+  AvailableInFutureSwift()
 }
 
 // MARK: Global functions
 
-func available_func( // expected-note * {{add @available attribute to enclosing global function}}
+func available_func( // expected-note * {{add '@available' attribute to enclosing global function}}
   _: AlwaysAvailable,
   _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   _: UnavailableInSwift4, // expected-error {{'UnavailableInSwift4' is unavailable}}
@@ -60,33 +60,33 @@ func never_available_func(
   always()
   never() // expected-error {{'never()' is unavailable}}
   unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
 }
 
 @available(swift, obsoleted: 4)
 func unavailable_in_swift4_func(
   _: AlwaysAvailable,
-  _: NeverAvailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   _: UnavailableInSwift4,
   _: AvailableInFutureSwift,
 ) {
   always()
   never() // expected-error {{'never()' is unavailable}}
   unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
 }
 
 @available(swift, introduced: 99)
 func introduced_in_future_swift_func(
   _: AlwaysAvailable,
-  _: NeverAvailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   _: UnavailableInSwift4,
   _: AvailableInFutureSwift,
 ) {
   always()
   never() // expected-error {{'never()' is unavailable}}
   unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
 }
 
 // MARK: Global vars
@@ -113,33 +113,33 @@ var never_var: (
   always(),
   never(), // expected-error {{'never()' is unavailable}}
   unavailableInSwift4(), // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift(), // expected-error {{'availableInFutureSwift()' is unavailable}}
+  availableInFutureSwift(), // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
 )
 
 @available(swift, obsoleted: 4)
 var unavailable_in_swift4_var: (
   AlwaysAvailable,
-  NeverAvailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   UnavailableInSwift4,
   AvailableInFutureSwift
 ) = (
   always(),
   never(), // expected-error {{'never()' is unavailable}}
   unavailableInSwift4(), // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift(), // expected-error {{'availableInFutureSwift()' is unavailable}}
+  availableInFutureSwift(), // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
 )
 
 @available(swift, introduced: 99)
 var available_in_future_swift_var: (
   AlwaysAvailable,
-  NeverAvailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   UnavailableInSwift4,
   AvailableInFutureSwift
 ) = (
   always(),
   never(), // expected-error {{'never()' is unavailable}}
   unavailableInSwift4(), // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift(), // expected-error {{'availableInFutureSwift()' is unavailable}}
+  availableInFutureSwift(), // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
 )
 
 
@@ -156,27 +156,29 @@ struct AlwaysAvailableContainer {
 }
 
 @available(*, unavailable)
-struct NeverAvailableContainer { // expected-note {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
+struct NeverAvailableContainer { // expected-note 3 {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
   let always_var: AlwaysAvailable = always()
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
   let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
 }
 
 @available(swift, obsoleted: 4)
 struct UnavailableInSwift4Container { // expected-note {{'UnavailableInSwift4Container' was obsoleted in Swift 4}}
   let always_var: AlwaysAvailable = always()
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
   let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
 }
 
 @available(swift, introduced: 99)
 struct AvailableInFutureSwiftContainer { // expected-note {{'AvailableInFutureSwiftContainer' was introduced in Swift 99}}
   let always_var: AlwaysAvailable = always()
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
-  let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
+  let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4()  // expected-error {{'unavailableInSwift4()' is unavailable}}
+  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift()  // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
 }
 
 // MARK: Extensions
@@ -198,7 +200,7 @@ extension AvailableInFutureSwiftContainer {}
 @available(swift, obsoleted: 4)
 extension AlwaysAvailableContainer {}
 @available(swift, obsoleted: 4)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
 @available(swift, obsoleted: 4)
 extension UnavailableInSwift4Container {}
 @available(swift, obsoleted: 4)
@@ -207,7 +209,7 @@ extension AvailableInFutureSwiftContainer {}
 @available(swift, introduced: 99)
 extension AlwaysAvailableContainer {}
 @available(swift, introduced: 99)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
 @available(swift, introduced: 99)
 extension UnavailableInSwift4Container {}
 @available(swift, introduced: 99)
@@ -219,7 +221,7 @@ struct ExtendMe {}
 extension ExtendMe {
   func never_available_extension_available_method() {} // expected-note {{has been explicitly marked unavailable here}}
 
-  func never_available_extension_available_method( // expected-note * {{add @available attribute to enclosing instance method}}
+  func never_available_extension_available_method( // expected-note * {{add '@available' attribute to enclosing instance method}}
     _: AlwaysAvailable,
     _: NeverAvailable,
     _: UnavailableInSwift4,
@@ -228,7 +230,7 @@ extension ExtendMe {
     always()
     never() // expected-error {{'never()' is unavailable}}
     unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
   }
 
   @available(*, unavailable)
@@ -241,7 +243,7 @@ extension ExtendMe {
     always()
     never() // expected-error {{'never()' is unavailable}}
     unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
   }
 
   @available(swift, obsoleted: 4)
@@ -254,7 +256,7 @@ extension ExtendMe {
     always()
     never() // expected-error {{'never()' is unavailable}}
     unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
   }
 
   @available(swift, introduced: 99)
@@ -267,9 +269,8 @@ extension ExtendMe {
     always()
     never() // expected-error {{'never()' is unavailable}}
     unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
   }
-
 }
 
 @available(swift, obsoleted: 4)
@@ -286,7 +287,7 @@ extension ExtendMe {
     always()
     never() // expected-error {{'never()' is unavailable}}
     unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
   }
 }
 
@@ -304,7 +305,7 @@ extension ExtendMe {
     always()
     never() // expected-error {{'never()' is unavailable}}
     unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable in Swift}}
   }
 }
 
diff --git a/test/attr/attr_availability_transitive_osx.swift b/test/attr/attr_availability_transitive_osx.swift
index b0a17ee2f3b93..898842d49a67b 100644
--- a/test/attr/attr_availability_transitive_osx.swift
+++ b/test/attr/attr_availability_transitive_osx.swift
@@ -59,7 +59,7 @@ func osx_extension() -> OSXAppExtensionsUnavailable {
 
 // MARK: Global functions
 
-func available_func( // expected-note * {{add @available attribute to enclosing global function}}
+func available_func( // expected-note * {{add '@available' attribute to enclosing global function}}
   _: AlwaysAvailable,
   _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   _: OSXFutureAvailable, // expected-error {{'OSXFutureAvailable' is only available in macOS 99 or newer}}
@@ -87,8 +87,7 @@ func never_available_func(
 ) {
   always()
   never() // expected-error {{'never()' is unavailable}}
-  osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-  // expected-note@-1 {{add 'if #available' version check}}
+  osx_future()
   osx()
   osx_ios()
   osx_extension()
@@ -97,7 +96,7 @@ func never_available_func(
 @available(OSX, unavailable)
 func osx_func(
   _: AlwaysAvailable,
-  _: NeverAvailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   _: OSXFutureAvailable,
   _: OSXUnavailable,
   _: MultiPlatformUnavailable,
@@ -105,15 +104,14 @@ func osx_func(
 ) {
   always()
   never() // expected-error {{'never()' is unavailable}}
-  osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-  // expected-note@-1 {{add 'if #available' version check}}
+  osx_future()
   osx()
   osx_ios()
   osx_extension()
 }
 
 @available(OSXApplicationExtension, unavailable)
-func osx_extension_func( // expected-note 2 {{add @available attribute to enclosing global function}}
+func osx_extension_func( // expected-note 2 {{add '@available' attribute to enclosing global function}}
   _: AlwaysAvailable,
   _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   _: OSXFutureAvailable, // expected-error {{'OSXFutureAvailable' is only available in macOS 99 or newer}}
@@ -132,7 +130,7 @@ func osx_extension_func( // expected-note 2 {{add @available attribute to enclos
 
 // MARK: Global vars
 
-var always_var: ( // expected-note 2 {{add @available attribute to enclosing var}}
+var always_var: ( // expected-note 2 {{add '@available' attribute to enclosing var}}
   AlwaysAvailable,
   NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   OSXFutureAvailable, // expected-error {{'OSXFutureAvailable' is only available in macOS 99 or newer}}
@@ -159,7 +157,7 @@ var never_var: (
 ) = (
   always(),
   never(), // expected-error {{'never()' is unavailable}}
-  osx_future(), // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
+  osx_future(),
   osx(),
   osx_ios(),
   osx_extension()
@@ -168,7 +166,7 @@ var never_var: (
 @available(OSX, unavailable)
 var osx_var: (
   AlwaysAvailable,
-  NeverAvailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   OSXFutureAvailable,
   OSXUnavailable,
   MultiPlatformUnavailable,
@@ -176,14 +174,14 @@ var osx_var: (
 ) = (
   always(),
   never(), // expected-error {{'never()' is unavailable}}
-  osx_future(), // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
+  osx_future(),
   osx(),
   osx_ios(),
   osx_extension()
 )
 
 @available(OSXApplicationExtension, unavailable)
-var osx_extension_var: ( // expected-note 2 {{add @available attribute to enclosing var}}
+var osx_extension_var: ( // expected-note 2 {{add '@available' attribute to enclosing var}}
   AlwaysAvailable,
   NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   OSXFutureAvailable, // expected-error {{'OSXFutureAvailable' is only available in macOS 99 or newer}}
@@ -201,7 +199,7 @@ var osx_extension_var: ( // expected-note 2 {{add @available attribute to enclos
 
 // MARK: Properties
 
-struct AlwaysAvailableContainer { // expected-note 2 {{add @available attribute to enclosing struct}}
+struct AlwaysAvailableContainer { // expected-note 2 {{add '@available' attribute to enclosing struct}}
   let always_var: AlwaysAvailable = always()
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
   // expected-error@-1 {{'NeverAvailable' is unavailable}}
@@ -215,10 +213,10 @@ struct AlwaysAvailableContainer { // expected-note 2 {{add @available attribute
 }
 
 @available(*, unavailable)
-struct NeverAvailableContainer { // expected-note 2 {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
+struct NeverAvailableContainer { // expected-note 3 {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
   let always_var: AlwaysAvailable = always()
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
-  let osx_future_var: OSXFutureAvailable = osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
+  let osx_future_var: OSXFutureAvailable = osx_future()
   let osx_var: OSXUnavailable = osx()
   let osx_ios_var: MultiPlatformUnavailable = osx_ios()
   let osx_extension_var: OSXAppExtensionsUnavailable = osx_extension()
@@ -228,14 +226,15 @@ struct NeverAvailableContainer { // expected-note 2 {{'NeverAvailableContainer'
 struct OSXUnavailableContainer { // expected-note 2 {{'OSXUnavailableContainer' has been explicitly marked unavailable here}}
   let always_var: AlwaysAvailable = always()
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
-  let osx_future_var: OSXFutureAvailable = osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
+  let osx_future_var: OSXFutureAvailable = osx_future()
   let osx_var: OSXUnavailable = osx()
   let osx_ios_var: MultiPlatformUnavailable = osx_ios()
   let osx_extension_var: OSXAppExtensionsUnavailable = osx_extension()
 }
 
 @available(OSXApplicationExtension, unavailable)
-struct OSXAppExtensionsUnavailableContainer { // expected-note 2 {{add @available attribute to enclosing struct}}
+struct OSXAppExtensionsUnavailableContainer { // expected-note 2 {{add '@available' attribute to enclosing struct}}
   let always_var: AlwaysAvailable = always()
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
   // expected-error@-1 {{'NeverAvailable' is unavailable}}
@@ -267,7 +266,7 @@ extension OSXAppExtensionsUnavailableContainer {}
 @available(OSX, unavailable)
 extension AlwaysAvailableContainer {}
 @available(OSX, unavailable)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
 @available(OSX, unavailable)
 extension OSXUnavailableContainer {}
 @available(OSX, unavailable)
@@ -291,7 +290,7 @@ extension ExtendMe {
   @available(OSX 99, *)
   func never_available_extension_osx_future_method() {} // expected-note {{has been explicitly marked unavailable here}}
 
-  func never_available_extension_available_method( // expected-note * {{add @available attribute to enclosing instance method}}
+  func never_available_extension_available_method( // expected-note * {{add '@available' attribute to enclosing instance method}}
     _: AlwaysAvailable,
     _: NeverAvailable,
     _: OSXFutureAvailable,
@@ -301,8 +300,7 @@ extension ExtendMe {
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
@@ -319,8 +317,7 @@ extension ExtendMe {
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
@@ -337,15 +334,14 @@ extension ExtendMe {
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
   }
 
   @available(OSXApplicationExtension, unavailable)
-  func never_available_extension_osx_app_extension_method( // expected-note {{add @available attribute to enclosing instance method}}
+  func never_available_extension_osx_app_extension_method(
     _: AlwaysAvailable,
     _: NeverAvailable,
     _: OSXFutureAvailable,
@@ -355,8 +351,7 @@ extension ExtendMe {
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
@@ -370,9 +365,9 @@ extension ExtendMe {
   @available(OSX 99, *)
   func osx_extension_osx_future_method() {} // expected-note {{has been explicitly marked unavailable here}}
 
-  func osx_extension_available_method( // expected-note * {{add @available attribute to enclosing instance method}}
+  func osx_extension_available_method( // expected-note * {{add '@available' attribute to enclosing instance method}}
     _: AlwaysAvailable,
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXFutureAvailable,
     _: OSXUnavailable,
     _: MultiPlatformUnavailable,
@@ -380,8 +375,7 @@ extension ExtendMe {
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
@@ -398,8 +392,7 @@ extension ExtendMe {
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
@@ -408,7 +401,7 @@ extension ExtendMe {
   @available(OSX, unavailable)
   func osx_extension_osx_method(
     _: AlwaysAvailable,
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXFutureAvailable,
     _: OSXUnavailable,
     _: MultiPlatformUnavailable,
@@ -416,17 +409,16 @@ extension ExtendMe {
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
   }
 
   @available(OSXApplicationExtension, unavailable)
-  func osx_extension_osx_app_extension_method( // expected-note {{add @available attribute to enclosing instance method}}
+  func osx_extension_osx_app_extension_method(
     _: AlwaysAvailable,
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXFutureAvailable,
     _: OSXUnavailable,
     _: MultiPlatformUnavailable,
@@ -434,8 +426,7 @@ extension ExtendMe {
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
@@ -443,13 +434,13 @@ extension ExtendMe {
 }
 
 @available(OSXApplicationExtension, unavailable)
-extension ExtendMe { // expected-note * {{add @available attribute to enclosing extension}}
+extension ExtendMe { // expected-note * {{add '@available' attribute to enclosing extension}}
   func osx_app_extension_extension_available_method() {}
 
   @available(OSX 99, *)
   func osx_app_extension_extension_osx_future_method() {}
 
-  func osx_app_extension_extension_available_method( // expected-note * {{add @available attribute to enclosing instance method}}
+  func osx_app_extension_extension_available_method( // expected-note * {{add '@available' attribute to enclosing instance method}}
     _: AlwaysAvailable,
     _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXFutureAvailable, // expected-error {{'OSXFutureAvailable' is only available in macOS 99 or newer}}
@@ -477,8 +468,7 @@ extension ExtendMe { // expected-note * {{add @available attribute to enclosing
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
@@ -487,7 +477,7 @@ extension ExtendMe { // expected-note * {{add @available attribute to enclosing
   @available(OSX, unavailable)
   func osx_app_extension_extension_osx_method(
     _: AlwaysAvailable,
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXFutureAvailable,
     _: OSXUnavailable,
     _: MultiPlatformUnavailable,
@@ -495,15 +485,14 @@ extension ExtendMe { // expected-note * {{add @available attribute to enclosing
   ) {
     always()
     never() // expected-error {{'never()' is unavailable}}
-    osx_future() // expected-error {{'osx_future()' is only available in macOS 99 or newer}}
-    // expected-note@-1 {{add 'if #available' version check}}
+    osx_future()
     osx()
     osx_ios()
     osx_extension()
   }
 
   @available(OSXApplicationExtension, unavailable)
-  func osx_app_extension_extension_osx_app_extension_method( // expected-note 2 {{add @available attribute to enclosing instance method}}
+  func osx_app_extension_extension_osx_app_extension_method( // expected-note 2 {{add '@available' attribute to enclosing instance method}}
     _: AlwaysAvailable,
     _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXFutureAvailable, // expected-error {{'OSXFutureAvailable' is only available in macOS 99 or newer}}
@@ -521,7 +510,7 @@ extension ExtendMe { // expected-note * {{add @available attribute to enclosing
   }
 }
 
-func available_func_call_extension_methods(_ e: ExtendMe) { // expected-note {{add @available attribute to enclosing global function}}
+func available_func_call_extension_methods(_ e: ExtendMe) { // expected-note {{add '@available' attribute to enclosing global function}}
   e.never_available_extension_available_method() // expected-error {{'never_available_extension_available_method()' is unavailable}}
   e.osx_extension_available_method() // expected-error {{'osx_extension_available_method()' is unavailable in macOS}}
   e.osx_app_extension_extension_available_method()
@@ -534,7 +523,7 @@ func available_func_call_extension_methods(_ e: ExtendMe) { // expected-note {{a
 }
 
 @available(OSX, obsoleted: 10.9)
-struct OSXObsoleted {} // expected-note 2 {{'OSXObsoleted' was obsoleted in macOS 10.9}}
+struct OSXObsoleted {}
 
 @available(OSX, unavailable)
 @available(OSX, introduced: 99)
@@ -561,18 +550,45 @@ func osx_unavailable_func(
   OSXUnavailableAndIntroducedInFutureSameAttribute,
   OSXIntroducedInFutureAndUnavailable
 ) {
-  // FIXME: [availability] Stop diagnosing potential unavailability or obsoletion in an unavailable context.
-  _ = OSXFutureAvailable() // expected-error {{'OSXFutureAvailable' is only available in macOS 99 or newer}}
-  // expected-note@-1 {{add 'if #available' version check}}
-  _ = OSXObsoleted() // expected-error {{'OSXObsoleted' is unavailable in macOS}}
+  _ = OSXFutureAvailable()
+  _ = OSXObsoleted()
   _ = OSXUnavailableAndIntroducedInFuture()
   _ = OSXUnavailableAndIntroducedInFutureSameAttribute()
   _ = OSXIntroducedInFutureAndUnavailable()
 
   func takesType<T>(_ t: T.Type) {}
-  takesType(OSXFutureAvailable.self) // expected-error {{'OSXFutureAvailable' is only available in macOS 99 or newer}}
-  // expected-note@-1 {{add 'if #available' version check}}
-  takesType(OSXObsoleted.self) // expected-error {{'OSXObsoleted' is unavailable in macOS}}
+  takesType(OSXFutureAvailable.self)
+  takesType(OSXObsoleted.self)
+  takesType(OSXUnavailableAndIntroducedInFuture.self)
+  takesType(OSXUnavailableAndIntroducedInFutureSameAttribute.self)
+  takesType(OSXIntroducedInFutureAndUnavailable.self)
+
+  return (s1, s2, s3, s4, s5)
+}
+
+@available(OSX, unavailable, introduced: 99)
+func osx_unavailable_and_introduced_func(
+  _ s1: OSXFutureAvailable,
+  _ s2: OSXObsoleted,
+  _ s3: OSXUnavailableAndIntroducedInFuture,
+  _ s4: OSXUnavailableAndIntroducedInFutureSameAttribute,
+  _ s5: OSXIntroducedInFutureAndUnavailable,
+) -> (
+  OSXFutureAvailable,
+  OSXObsoleted,
+  OSXUnavailableAndIntroducedInFuture,
+  OSXUnavailableAndIntroducedInFutureSameAttribute,
+  OSXIntroducedInFutureAndUnavailable
+) {
+  _ = OSXFutureAvailable()
+  _ = OSXObsoleted()
+  _ = OSXUnavailableAndIntroducedInFuture()
+  _ = OSXUnavailableAndIntroducedInFutureSameAttribute()
+  _ = OSXIntroducedInFutureAndUnavailable()
+
+  func takesType<T>(_ t: T.Type) {}
+  takesType(OSXFutureAvailable.self)
+  takesType(OSXObsoleted.self)
   takesType(OSXUnavailableAndIntroducedInFuture.self)
   takesType(OSXUnavailableAndIntroducedInFutureSameAttribute.self)
   takesType(OSXIntroducedInFutureAndUnavailable.self)
diff --git a/test/attr/attr_availability_transitive_osx_appext.swift b/test/attr/attr_availability_transitive_osx_appext.swift
index 412af439ffe15..032e1834cfe88 100644
--- a/test/attr/attr_availability_transitive_osx_appext.swift
+++ b/test/attr/attr_availability_transitive_osx_appext.swift
@@ -55,7 +55,7 @@ func never_available_func(
 
 @available(OSX, unavailable)
 func osx_func(
-  _: NeverAvailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   _: OSXUnavailable,
   _: OSXAppExtensionsUnavailable
 ) {
@@ -66,8 +66,8 @@ func osx_func(
 
 @available(OSXApplicationExtension, unavailable)
 func osx_extension_func(
-  _: NeverAvailable,
-  _: OSXUnavailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
+  _: OSXUnavailable, // expected-error {{'OSXUnavailable' is unavailable in macOS}}
   _: OSXAppExtensionsUnavailable
 ) {
   never() // expected-error {{'never()' is unavailable}}
@@ -100,7 +100,7 @@ var never_var: (
 
 @available(OSX, unavailable)
 var osx_var: (
-  NeverAvailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
   OSXUnavailable,
   OSXAppExtensionsUnavailable
 ) = (
@@ -111,8 +111,8 @@ var osx_var: (
 
 @available(OSXApplicationExtension, unavailable)
 var osx_extension_var: (
-  NeverAvailable,
-  OSXUnavailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
+  OSXUnavailable, // expected-error {{'OSXUnavailable' is unavailable in macOS}}
   OSXAppExtensionsUnavailable
 ) = (
   never(), // expected-error {{'never()' is unavailable}}
@@ -132,15 +132,16 @@ struct AlwaysAvailabileContainer {
 }
 
 @available(*, unavailable)
-struct NeverAvailableContainer { // expected-note {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
+struct NeverAvailableContainer { // expected-note 3 {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
   let osx_var: OSXUnavailable = osx()
   let osx_extension_var: OSXAppExtensionsUnavailable = osx_extension()
 }
 
 @available(OSX, unavailable)
-struct OSXUnavailableContainer { // expected-note {{'OSXUnavailableContainer' has been explicitly marked unavailable here}}
+struct OSXUnavailableContainer { // expected-note 2 {{'OSXUnavailableContainer' has been explicitly marked unavailable here}}
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
   let osx_var: OSXUnavailable = osx()
   let osx_extension_var: OSXAppExtensionsUnavailable = osx_extension()
 }
@@ -148,7 +149,9 @@ struct OSXUnavailableContainer { // expected-note {{'OSXUnavailableContainer' ha
 @available(OSXApplicationExtension, unavailable)
 struct OSXAppExtensionsUnavailableContainer { // expected-note {{'OSXAppExtensionsUnavailableContainer' has been explicitly marked unavailable here}}
   let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
   let osx_var: OSXUnavailable = osx() // expected-error {{'osx()' is unavailable}}
+  // expected-error@-1 {{'OSXUnavailable' is unavailable in macOS}}
   let osx_extension_var: OSXAppExtensionsUnavailable = osx_extension()
 }
 
@@ -171,7 +174,7 @@ extension OSXAppExtensionsUnavailableContainer {}
 @available(OSX, unavailable)
 extension AlwaysAvailabileContainer {}
 @available(OSX, unavailable)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
 @available(OSX, unavailable)
 extension OSXUnavailableContainer {}
 @available(OSX, unavailable)
@@ -180,9 +183,9 @@ extension OSXAppExtensionsUnavailableContainer {}
 @available(OSXApplicationExtension, unavailable)
 extension AlwaysAvailabileContainer {}
 @available(OSXApplicationExtension, unavailable)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
 @available(OSXApplicationExtension, unavailable)
-extension OSXUnavailableContainer {}
+extension OSXUnavailableContainer {} // expected-error {{'OSXUnavailableContainer' is unavailable in macOS}}
 @available(OSXApplicationExtension, unavailable)
 extension OSXAppExtensionsUnavailableContainer {}
 
@@ -256,7 +259,7 @@ extension ExtendMe {
   func osx_extension_osx_app_extension_method() {} // expected-note 2 {{'osx_extension_osx_app_extension_method()' has been explicitly marked unavailable here}}
 
   func osx_extension_available_method(
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXUnavailable,
     _: OSXAppExtensionsUnavailable
   ) {
@@ -278,7 +281,7 @@ extension ExtendMe {
 
   @available(OSX, unavailable)
   func osx_extension_osx_method(
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXUnavailable,
     _: OSXAppExtensionsUnavailable
   ) {
@@ -289,7 +292,7 @@ extension ExtendMe {
 
   @available(OSXApplicationExtension, unavailable)
   func osx_extension_osx_app_extension_method(
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXUnavailable,
     _: OSXAppExtensionsUnavailable
   ) {
@@ -316,8 +319,8 @@ extension ExtendMe {
   func osx_app_extension_extension_osx_app_extension_method() {} // expected-note {{'osx_app_extension_extension_osx_app_extension_method()' has been explicitly marked unavailable here}}
 
   func osx_app_extension_extension_available_method(
-    _: NeverAvailable,
-    _: OSXUnavailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
+    _: OSXUnavailable, // expected-error {{'OSXUnavailable' is unavailable in macOS}}
     _: OSXAppExtensionsUnavailable
   ) {
     never() // expected-error {{'never()' is unavailable}}
@@ -338,7 +341,7 @@ extension ExtendMe {
 
   @available(OSX, unavailable)
   func osx_app_extension_extension_osx_method(
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
     _: OSXUnavailable,
     _: OSXAppExtensionsUnavailable
   ) {
@@ -349,8 +352,8 @@ extension ExtendMe {
 
   @available(OSXApplicationExtension, unavailable)
   func osx_app_extension_extension_osx_app_extension_method(
-    _: NeverAvailable,
-    _: OSXUnavailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
+    _: OSXUnavailable, // expected-error {{'OSXUnavailable' is unavailable in macOS}}
     _: OSXAppExtensionsUnavailable
   ) {
     never() // expected-error {{'never()' is unavailable}}
@@ -386,8 +389,7 @@ func osx_func_call_extension_methods(_ e: ExtendMe) {
 
   e.never_available_extension_osx_future_method() // expected-error {{'never_available_extension_osx_future_method()' is unavailable}}
   e.osx_extension_osx_future_method()
-  e.osx_app_extension_extension_osx_future_method() // expected-error {{'osx_app_extension_extension_osx_future_method()' is only available in macOS 99 or newer}}
-  // expected-note@-1 {{add 'if #available' version check}}
+  e.osx_app_extension_extension_osx_future_method()
   e.osx_app_extension_extension_never_available_method() // expected-error {{'osx_app_extension_extension_never_available_method()' is unavailable}}
   e.osx_app_extension_extension_osx_method()
   e.osx_app_extension_extension_osx_app_extension_method()
@@ -414,7 +416,7 @@ func osx_app_ext_func_call_extension_methods(_ e: ExtendMe) {
 @available(OSXApplicationExtension, introduced: 99)
 func osx_app_extensions_future() {}
 
-func call_osx_app_extensions_future() { // expected-note {{add @available attribute to enclosing global function}} {{1-1=@available(macOSApplicationExtension 99, *)\n}}
+func call_osx_app_extensions_future() { // expected-note {{add '@available' attribute to enclosing global function}} {{1-1=@available(macOSApplicationExtension 99, *)\n}}
   osx_app_extensions_future() // expected-error {{'osx_app_extensions_future()' is only available in application extensions for macOS 99 or newer}}
   // expected-note@-1 {{add 'if #available' version check}} {{3-30=if #available(macOS 99, *) {\n      osx_app_extensions_future()\n  \} else {\n      // Fallback on earlier versions\n  \}}}
 }
diff --git a/test/attr/attr_availability_unavailable_query.swift b/test/attr/attr_availability_unavailable_query.swift
index 08892809c2289..3f4e3ac34e963 100644
--- a/test/attr/attr_availability_unavailable_query.swift
+++ b/test/attr/attr_availability_unavailable_query.swift
@@ -9,7 +9,7 @@ func foo() -> Int { return 0 }
 func bar() -> Int { return 0 }
 
 // Verify that #unavailable is the opposite of #available.
-// expected-note@+1 *{{add @available attribute to enclosing global function}}
+// expected-note@+1 *{{add '@available' attribute to enclosing global function}}
 func testUnavailable() {
   if #unavailable(macOS 998.0) {
     foo() // expected-error{{'foo()' is only available in macOS 998.0 or newer}}
@@ -32,7 +32,7 @@ func testUnavailable() {
 }
 
 // Verify that #unavailable doesn't complain about useless specs.
-// expected-note@+1 *{{add @available attribute to enclosing global function}}
+// expected-note@+1 *{{add '@available' attribute to enclosing global function}}
 func testUnavailableDoesntWarnUselessSpecs() {
   if #unavailable(macOS 998.0), #unavailable(macOS 999.0) {
     foo() // expected-error{{'foo()' is only available in macOS 998.0 or newer}}
@@ -46,7 +46,7 @@ func testUnavailableDoesntWarnUselessSpecs() {
 }
 
 // Verify that #unavailable refines the availability of all "else" paths.
-// expected-note@+1 *{{add @available attribute to enclosing global function}}
+// expected-note@+1 *{{add '@available' attribute to enclosing global function}}
 func testUnavailableExpandAllElsePaths() {
   if #unavailable(macOS 998.0) {
     foo() // expected-error{{'foo()' is only available in macOS 998.0 or newer}}
diff --git a/test/attr/attr_availability_vision.swift b/test/attr/attr_availability_vision.swift
index 7e41d936ba43a..d7fb905a6f735 100644
--- a/test/attr/attr_availability_vision.swift
+++ b/test/attr/attr_availability_vision.swift
@@ -41,12 +41,12 @@ class DeprecatedClass { }
 
 func functionWithDeprecatedParameter(p: DeprecatedClass) { } // expected-warning{{'DeprecatedClass' was deprecated in visionOS 2.0: Use BetterClass instead}}
 
-@available(visionOS, introduced: 2.0, deprecated: 4.0,
+@available(visionOS, introduced: 2.0, deprecated: 2.1,
            message: "Use BetterClass instead")
-class DeprecatedClassIn3_0 { }
+class DeprecatedClassIn2_1 { }
 
 // Elements deprecated later than the minimum deployment target (which is 2.0, in this case) should not generate warnings
-func functionWithDeprecatedLaterParameter(p: DeprecatedClassIn3_0) { }
+func functionWithDeprecatedLaterParameter(p: DeprecatedClassIn2_1) { }
 
 // Treat visionOS as an alias for iOS in availability queries
 
diff --git a/test/attr/attr_backDeployed.swift b/test/attr/attr_backDeployed.swift
index d1f051f5cc742..7cdc676308789 100644
--- a/test/attr/attr_backDeployed.swift
+++ b/test/attr/attr_backDeployed.swift
@@ -34,6 +34,18 @@ public struct TopLevelStruct {
     set(newValue) {}
   }
 
+  @backDeployed(before: macOS 12.0)
+  public private(set) var readWritePropertyPrivateSet: Int {
+    get { 42 }
+    set(newValue) {}
+  }
+
+  @backDeployed(before: macOS 12.0)
+  public internal(set) var readWritePropertyInternalSet: Int {
+    get { 42 }
+    set(newValue) {}
+  }
+
   @backDeployed(before: macOS 12.0)
   public subscript(at index: Int) -> Int {
     get { 42 }
@@ -205,6 +217,19 @@ extension TopLevelProtocol {
   public func backDeployedExtensionMethod() {}
 }
 
+@backDeployed(before: macOS 16.0, iOS 19.0, tvOS 19.0, watchOS 12.0, visionOS 3.0)
+public func backDeployedBeforeVersionsMappingTo26() -> Int { 26 }
+
+@backDeployed(before: macOS 17.0, iOS 20.0, tvOS 20.0, watchOS 13.0, visionOS 4.0)
+// expected-warning@-1 {{'17.0' is not a valid version number for macOS}}
+// expected-warning@-2 {{'20.0' is not a valid version number for iOS}}
+// expected-warning@-3 {{'20.0' is not a valid version number for tvOS}}
+// expected-warning@-4 {{'13.0' is not a valid version number for watchOS}}
+// expected-warning@-5 {{'4.0' is not a valid version number for visionOS}}
+public func backDeployedBeforeVersionsMappingTo27() -> Int { 27 }
+
+@backDeployed(before: macOS 26.0, iOS 26.0, tvOS 26.0, watchOS 26.0, visionOS 26.0)
+public func backDeployedBefore26() -> Int { 26 }
 
 // MARK: - Unsupported declaration kinds
 
@@ -221,7 +246,6 @@ public final class CannotBackDeployClassDeinit {
   deinit {}
 }
 
-// Ok, final decls in a non-final, derived class
 public class CannotBackDeployOverride: TopLevelClass {
   @backDeployed(before: macOS 12.0) // expected-error {{'@backDeployed' cannot be combined with 'override'}}
   final public override func hook() {}
@@ -280,6 +304,40 @@ public func cannotBackDeployFuncWithOpaqueResultType() -> some TopLevelProtocol
   return ConformsToTopLevelProtocol()
 }
 
+public struct CannotBackDeployNonPublicAccessors {
+  private var privateVar: Int {
+    @backDeployed(before: macOS 12.0) // expected-error {{'@backDeployed' may not be used on private declarations}}
+    get { 0 }
+
+    @backDeployed(before: macOS 12.0) // expected-error {{'@backDeployed' may not be used on private declarations}}
+    set { }
+  }
+
+  internal var internalVar: Int {
+    @backDeployed(before: macOS 12.0) // expected-error {{'@backDeployed' may not be used on internal declarations}}
+    get { 0 }
+
+    @backDeployed(before: macOS 12.0) // expected-error {{'@backDeployed' may not be used on internal declarations}}
+    set { }
+  }
+
+  public private(set) var publicVarPrivateSet: Int {
+    @backDeployed(before: macOS 12.0)
+    get { 0 }
+
+    @backDeployed(before: macOS 12.0) // expected-error {{'@backDeployed' may not be used on private declarations}}
+    set { }
+  }
+
+  public internal(set) var publicVarInternalSet: Int {
+    @backDeployed(before: macOS 12.0)
+    get { 0 }
+
+    @backDeployed(before: macOS 12.0) // expected-error {{'@backDeployed' may not be used on internal declarations}}
+    set { }
+  }
+}
+
 // MARK: - Function body diagnostics
 
 public struct FunctionBodyDiagnostics {
diff --git a/test/attr/attr_backDeployed_availability_visionos.swift b/test/attr/attr_backDeployed_availability_visionos.swift
index 29140b53d1954..53b7fcef8630e 100644
--- a/test/attr/attr_backDeployed_availability_visionos.swift
+++ b/test/attr/attr_backDeployed_availability_visionos.swift
@@ -1,6 +1,6 @@
-// RUN: %target-typecheck-verify-swift -parse-as-library
-
-// REQUIRES: OS=xros
+// RUN: %empty-directory(%t/mock-sdk)
+// RUN: cp %S/../Inputs/MockPlatformRemapSDKConfig/SDKSettings.json %t/mock-sdk/SDKSettings.json
+// RUN: %swift -typecheck -verify -parse-stdlib -target arm64-apple-xros1.0 %s -sdk %t/mock-sdk
 
 @backDeployed(before: visionOS 2) // Ok, introduced availability is inferred to be visionOS epoch
 public func topLevelFunc() {}
@@ -51,7 +51,7 @@ public func availableSameVersionAsBackDeploymentAndAlsoAvailableEarlierOniOS() {
 @backDeployed(before: visionOS 2) // expected-error {{'@backDeployed' has no effect because 'availableAfterBackDeployment()' is not available before visionOS 2}}
 public func availableAfterBackDeployment() {}
 
-@available(iOS 99, *) // expected-note {{'availableOniOSAfterBackDeploymentOniOS()' was introduced in visionOS 99}}
+@available(iOS 99, *) // expected-note {{'availableOniOSAfterBackDeploymentOniOS()' was introduced in iOS 99}}
 @backDeployed(before: iOS 17.4) // expected-error {{'@backDeployed' has no effect because 'availableOniOSAfterBackDeploymentOniOS()' is not available before visionOS 1.1}}
 public func availableOniOSAfterBackDeploymentOniOS() {}
 
diff --git a/test/attr/attr_borrowed.swift b/test/attr/attr_borrowed.swift
index f9f1ae5597390..f9f13a50a6235 100644
--- a/test/attr/attr_borrowed.swift
+++ b/test/attr/attr_borrowed.swift
@@ -11,7 +11,7 @@ func foo() -> String {}
 var string = ""
 
 @objc protocol P {
-  @_borrowed // expected-error {{property cannot be '@_borrowed' if it is an @objc protocol requirement}}
+  @_borrowed // expected-error {{property cannot be '@_borrowed' if it is an '@objc' protocol requirement}}
   var title: String { get }
 }
 
diff --git a/test/attr/attr_cdecl.swift b/test/attr/attr_cdecl.swift
index 63d241248ee7e..c2d9110a50896 100644
--- a/test/attr/attr_cdecl.swift
+++ b/test/attr/attr_cdecl.swift
@@ -8,7 +8,7 @@ func emptyName(x: Int) -> Int { return x }
 @_cdecl("noBody")
 func noBody(x: Int) -> Int // expected-error{{expected '{' in body of function}}
 
-@_cdecl("property") // expected-error{{may only be used on 'func' declarations}}
+@_cdecl("property") // expected-error{{'@_cdecl' attribute cannot be applied to this declaration}}
 var property: Int
 
 var computed: Int {
@@ -24,6 +24,9 @@ enum SwiftEnum { case A, B }
 @objc enum CEnum: Int { case A, B }
 #endif
 
+@_cdecl("enum") // expected-error {{@_cdecl may only be used on 'func' declarations}}
+enum UnderscoreCDeclEnum: CInt { case A, B }
+
 @_cdecl("swiftStruct")
 func swiftStruct(x: SwiftStruct) {} // expected-error{{cannot be represented}} expected-note{{Swift struct}}
 
@@ -40,10 +43,10 @@ class Foo {
   @_cdecl("Foo_foo_2") // expected-error{{can only be applied to global functions}}
   static func foo(x: Int) -> Int { return x }
 
-  @_cdecl("Foo_init") // expected-error{{may only be used on 'func'}}
+  @_cdecl("Foo_init") // expected-error{{'@_cdecl' attribute cannot be applied to this declaration}}
   init() {}
 
-  @_cdecl("Foo_deinit") // expected-error{{may only be used on 'func'}}
+  @_cdecl("Foo_deinit") // expected-error{{'@_cdecl' attribute cannot be applied to this declaration}}
   deinit {}
 }
 
diff --git a/test/attr/attr_cdecl_official.swift b/test/attr/attr_cdecl_official.swift
new file mode 100644
index 0000000000000..9be5f83af652c
--- /dev/null
+++ b/test/attr/attr_cdecl_official.swift
@@ -0,0 +1,203 @@
+/// @c attribute
+/// This test shouldn't require the objc runtime.
+
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify %s \
+// RUN:   -enable-experimental-feature CDecl -disable-objc-interop
+
+// REQUIRES: swift_feature_CDecl
+
+@c(cdecl_foo) func foo(x: Int) -> Int { return x }
+
+@c(not an identifier) func invalidName() {}
+// expected-error @-1 {{expected ')' in 'c' attribute}}
+// expected-error @-2 {{expected declaration}}
+
+@c() func emptyParen() {}
+// expected-error @-1 {{expected C identifier in 'c' attribute}}
+// expected-error @-2 {{expected declaration}}
+
+@c(42) func aNumber() {}
+// expected-error @-1 {{expected C identifier in 'c' attribute}}
+// expected-error @-2 {{expected declaration}}
+
+@c(a:selector:) func selectordName() {}
+// expected-error @-1 {{expected ')' in 'c' attribute}}
+// expected-error @-2 {{expected declaration}}
+
+@c func defaultName() {}
+
+@c("noBody")
+func noBody(x: Int) -> Int // expected-error{{expected '{' in body of function}}
+
+@c("property") // expected-error{{'@c' attribute cannot be applied to this declaration}}
+var property: Int
+
+var computed: Int {
+  @c("get_computed") get { return 0 }
+  @c("set_computed") set { return }
+}
+
+@c("inout")
+func noBody(x: inout Int) { } // expected-error{{global function cannot be marked '@c' because inout parameters cannot be represented in C}}
+
+struct SwiftStruct { var x, y: Int }
+enum SwiftEnum { case A, B }
+
+#if os(Windows) && (arch(x86_64) || arch(arm64))
+@c("CEnum") enum CEnum: Int32 { case A, B }
+#else
+@c("CEnum") enum CEnum: Int { case A, B }
+#endif
+
+@c enum CEnumDefaultName: CInt { case A, B }
+
+@c("CEnumNoRawType") enum CEnumNoRawType { case A, B }
+// expected-error @-1 {{'@c' enum must declare an integer raw type}}
+
+@c("CEnumStringRawType") enum CEnumStringRawType: String { case A, B }
+// expected-error @-1 {{'@c' enum raw type 'String' is not an integer type}}
+
+@c("swiftStruct")
+func swiftStruct(x: SwiftStruct) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{Swift structs cannot be represented in C}}
+
+@c("swiftEnum")
+func swiftEnum(x: SwiftEnum) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{Swift enums not marked '@c' cannot be represented in C}}
+
+@c("cEnum")
+func cEnum(x: CEnum) {}
+
+@c("CDeclAndObjC") // expected-error {{cannot apply both '@c' and '@objc' to enum}}
+@objc
+enum CDeclAndObjC: CInt { case A, B }
+
+@c("TwoCDecls") // expected-note {{attribute already specified here}}
+@_cdecl("TwoCDecls") // expected-error {{duplicate attribute}}
+func TwoCDecls() {}
+
+class Foo {
+  @c("Foo_foo") // expected-error{{@c can only be applied to global functions}}
+  func foo(x: Int) -> Int { return x }
+
+  @c("Foo_foo_2") // expected-error{{@c can only be applied to global functions}}
+  static func foo(x: Int) -> Int { return x }
+
+  @c("Foo_init") // expected-error{{'@c' attribute cannot be applied to this declaration}}
+  init() {}
+
+  @c("Foo_deinit") // expected-error{{'@c' attribute cannot be applied to this declaration}}
+  deinit {}
+}
+
+@c("throwing") // expected-error{{raising errors from @c functions is not supported}}
+func throwing() throws { }
+
+@c("acceptedPointers")
+func acceptedPointers(_ x: UnsafeMutablePointer<Int>,
+                        y: UnsafePointer<Int>,
+                        z: UnsafeMutableRawPointer,
+                        w: UnsafeRawPointer,
+                        u: OpaquePointer) {}
+
+@c("rejectedPointers")
+func rejectedPointers( // expected-error 6 {{global function cannot be marked '@c' because the type of the parameter}}
+    x: UnsafePointer<String>, // expected-note {{Swift structs cannot be represented in C}}
+    y: CVaListPointer, // expected-note {{Swift structs cannot be represented in C}}
+    z: UnsafeBufferPointer<Int>, // expected-note {{Swift structs cannot be represented in C}}
+    u: UnsafeMutableBufferPointer<Int>, // expected-note {{Swift structs cannot be represented in C}}
+    v: UnsafeRawBufferPointer, // expected-note {{Swift structs cannot be represented in C}}
+    t: UnsafeMutableRawBufferPointer) {} // expected-note {{Swift structs cannot be represented in C}}
+
+@c("genericParam")
+func genericParam<I>(i: I) {}
+// expected-error @-1 {{global function cannot be marked '@c' because it has generic parameters}}
+
+@c("variadic")
+func variadic(_: Int...) {}
+// expected-error @-1 {{global function cannot be marked '@c' because it has a variadic parameter}}
+
+@c("tupleParamEmpty")
+func tupleParamEmpty(a: ()) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{empty tuple type cannot be represented in C}}
+
+@c("tupleParam")
+func tupleParam(a: (Int, Float)) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{tuples cannot be represented in C}}
+
+@c("emptyTupleReturn")
+func emptyTupleReturn() -> () {}
+
+@c("tupleReturn")
+func tupleReturn() -> (Int, Float) { (1, 2.0) }
+// expected-error @-1 {{global function cannot be marked '@c' because its result type cannot be represented in C}}
+// expected-note @-2 {{tuples cannot be represented in C}}
+
+@c("funcAcceptsThrowingFunc")
+func funcAcceptsThrowingFunc(fn: (String) throws -> Int) { }
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{throwing function types cannot be represented in C}}
+
+@c("funcAcceptsThrowingFuncReturn")
+func funcAcceptsThrowingFuncReturn() -> (String) throws -> Int { fatalError() }
+// expected-error @-1 {{global function cannot be marked '@c' because its result type cannot be represented in C}}
+// expected-note @-2 {{throwing function types cannot be represented in C}}
+
+@c("bar")
+func bar(f: (SwiftEnum) -> SwiftStruct) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{function types cannot be represented in C unless their parameters and returns can be}}
+
+@c("bas")
+func bas(f: (SwiftEnum) -> ()) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{function types cannot be represented in C unless their parameters and returns can be}}
+
+@c("zim")
+func zim(f: () -> SwiftStruct) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{function types cannot be represented in C unless their parameters and returns can be}}
+
+@c("zang")
+func zang(f: (SwiftEnum, SwiftStruct) -> ()) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{function types cannot be represented in C unless their parameters and returns can be}}
+
+@c("zang_zang")
+  func zangZang(f: (Int...) -> ()) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{function types cannot be represented in C unless their parameters and returns can be}}
+
+@c("array")
+func array(i: [Int]) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{Swift structs cannot be represented in C}}
+
+class SwiftClass {}
+@c("swiftClass")
+func swiftClass(p: SwiftClass) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{classes cannot be represented in C}}
+
+protocol SwiftProtocol {}
+@c("swiftProtocol")
+func swiftProtocol(p: SwiftProtocol) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{protocols cannot be represented in C}}
+
+@c("swiftErrorProtocol")
+func swiftErrorProtocol(e: Error) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{protocols cannot be represented in C}}
+
+@c("anyParam")
+func anyParam(e:Any) {}
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{protocols cannot be represented in C}}
+
+@c func swift_allocBox() {} // expected-warning {{symbol name 'swift_allocBox' is reserved for the Swift runtime and cannot be directly referenced without causing unpredictable behavior; this will become an error}}
+@c(swift_allocObject) func swift_allocObject_renamed() {} // expected-warning {{symbol name 'swift_allocObject' is reserved for the Swift runtime and cannot be directly referenced without causing unpredictable behavior; this will become an error}}
diff --git a/test/attr/attr_cdecl_official_async.swift b/test/attr/attr_cdecl_official_async.swift
new file mode 100644
index 0000000000000..ab7154289a92b
--- /dev/null
+++ b/test/attr/attr_cdecl_official_async.swift
@@ -0,0 +1,17 @@
+// RUN: %target-typecheck-verify-swift -enable-objc-interop \
+// RUN:   -disable-availability-checking \
+// RUN:   -enable-experimental-feature CDecl
+
+// REQUIRES: concurrency
+// REQUIRES: swift_feature_CDecl
+
+@_cdecl("async") // expected-error{{@_cdecl global function cannot be asynchronous}}
+func asynchronous() async { }
+
+@c("async2") // expected-error{{@c global function cannot be asynchronous}}
+func asynchronous2() async { }
+
+@c("asyncParam")
+func asynchronousParam(fn: (String) async -> Int) { }
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{'async' function types cannot be represented in C}}
diff --git a/test/attr/attr_cdecl_official_rejected.swift b/test/attr/attr_cdecl_official_rejected.swift
new file mode 100644
index 0000000000000..37434b5dbcf86
--- /dev/null
+++ b/test/attr/attr_cdecl_official_rejected.swift
@@ -0,0 +1,12 @@
+// RUN: %target-typecheck-verify-swift
+// RUN: %target-swift-frontend -typecheck %s \
+// RUN:   -enable-experimental-feature CDecl
+
+// REQUIRES: swift_feature_CDecl
+
+@c("cdecl_foo") func foo() { } // expected-error {{'@c' requires '-enable-experimental-feature CDecl'}}
+
+var computed: Int {
+  @c("get_computed") get { return 0 } // expected-error {{'@c' requires '-enable-experimental-feature CDecl'}}
+  @c("set_computed") set { } // expected-error {{'@c' requires '-enable-experimental-feature CDecl'}}
+}
diff --git a/test/attr/attr_cdecl_official_with_objc.swift b/test/attr/attr_cdecl_official_with_objc.swift
new file mode 100644
index 0000000000000..8f23b7f810206
--- /dev/null
+++ b/test/attr/attr_cdecl_official_with_objc.swift
@@ -0,0 +1,42 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify %s \
+// RUN:   -enable-experimental-feature CDecl
+
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: objc_interop
+
+import Foundation
+
+@objc
+class ObjCClass: NSObject { }
+
+@c("objcClassReturn") func objcClassReturn() -> ObjCClass { fatalError() }
+// expected-error @-1 {{global function cannot be marked '@c' because its result type cannot be represented in C}}
+// expected-note @-2 {{classes cannot be represented in C}}
+
+@c("objcClassParams") func objcClassParams(a: ObjCClass, b: ObjCClass) { }
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter 1 cannot be represented in C}}
+// expected-error @-2 {{global function cannot be marked '@c' because the type of the parameter 2 cannot be represented in C}}
+// expected-note @-3 2 {{classes cannot be represented in C}}
+
+@objc
+protocol ObjCProtocol {}
+
+@c("objcProtocol") func objcProtocol(a: ObjCProtocol) { }
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{protocols cannot be represented in C}}
+
+@objc
+enum ObjCEnum: Int { case A, B }
+@c("objcEnumUseInCDecl") func objcEnumUseInCDecl(a: ObjCEnum) { }
+// expected-error @-1 {{global function cannot be marked '@c' because the type of the parameter cannot be represented in C}}
+// expected-note @-2 {{Swift enums not marked '@c' cannot be represented in C}}
+
+/// Objective-C accepts @c enums.
+@c("CEnum")
+enum CEnum: Int { case A, B }
+@_cdecl("cdeclEnumUseInObjc") func cdeclEnumUseInObjc(a: CEnum) { }
+
+enum SwiftEnum { case A, B }
+@_cdecl("swiftEnumUseInObjc") func swiftEnumUseInObjc(a: SwiftEnum) { }
+// expected-error @-1 {{global function cannot be marked '@_cdecl' because the type of the parameter cannot be represented in Objective-C}}
+// expected-note @-2 {{Swift enums not marked '@c' or '@objc' cannot be represented in Objective-C}}
diff --git a/test/attr/attr_concurrent.swift b/test/attr/attr_concurrent.swift
index e56e2a7e7a2ec..5a92c4cb77ce5 100644
--- a/test/attr/attr_concurrent.swift
+++ b/test/attr/attr_concurrent.swift
@@ -24,7 +24,7 @@ func acceptsNonConcurrent(_ fn: (Int) -> Int) { }
 
 func passingConcurrentOrNot(
   _ cfn: @Sendable (Int) -> Int,
-  ncfn: (Int) -> Int // expected-note{{parameter 'ncfn' is implicitly non-sendable}}{{9-9=@Sendable }}
+  ncfn: (Int) -> Int // expected-note{{parameter 'ncfn' is implicitly non-Sendable}}{{9-9=@Sendable }}
 ) {
   // Ambiguous because preconcurrency code doesn't consider `@Sendable`.
   f(cfn) // expected-error{{ambiguous use of 'f'}}
@@ -33,7 +33,7 @@ func passingConcurrentOrNot(
   f(ncfn)
 
   acceptsConcurrent(cfn) // okay
-  acceptsConcurrent(ncfn) // expected-warning{{passing non-sendable parameter 'ncfn' to function expecting a @Sendable closure}}
+  acceptsConcurrent(ncfn) // expected-warning{{passing non-Sendable parameter 'ncfn' to function expecting a '@Sendable' closure}}
   acceptsNonConcurrent(cfn) // okay
   acceptsNonConcurrent(ncfn) // okay
 
@@ -53,8 +53,8 @@ func closures() {
       return i
     })
 
-  let closure1 = { $0 + 1 } // inferred to be non-sendable
-  acceptsConcurrent(closure1) // expected-warning{{converting non-sendable function value to '@Sendable (Int) -> Int' may introduce data races}}
+  let closure1 = { $0 + 1 } // inferred to be non-Sendable
+  acceptsConcurrent(closure1) // expected-warning{{converting non-Sendable function value to '@Sendable (Int) -> Int' may introduce data races}}
 }
 
 // Mutation of captured locals from within @Sendable functions.
diff --git a/test/attr/attr_convention.swift b/test/attr/attr_convention.swift
index 93d8293551288..4263306471591 100644
--- a/test/attr/attr_convention.swift
+++ b/test/attr/attr_convention.swift
@@ -2,7 +2,7 @@
 
 let f1: (Int) -> Int = { $0 }
 let f2: @convention(swift) (Int) -> Int = { $0 }
-let f2a: @convention(swift, cType: "int *(int)") (Int32) -> Int32 = { $0 } // expected-error{{convention 'swift' does not support the 'cType' argument label, did you mean @convention(c, cType: "int *(int)") or @convention(block, cType: "int *(int)") instead?}}
+let f2a: @convention(swift, cType: "int *(int)") (Int32) -> Int32 = { $0 } // expected-error{{convention 'swift' does not support the 'cType' argument label, did you mean '@convention(c, cType: "int *(int)")' or '@convention(block, cType: "int *(int)")' instead?}}
 let f3: @convention(block) (Int) -> Int = { $0 }
 let f4: @convention(c) (Int) -> Int = { $0 }
 let f4a: @convention(c, cType: "int (int)") (Int32) -> Int32 = { $0 } // expected-error{{unable to parse 'int (int)'; it should be a C function pointer type or a block pointer type}}
diff --git a/test/attr/attr_dynamic.swift b/test/attr/attr_dynamic.swift
index 3f86dd1d48ddd..626f4d8bc431d 100644
--- a/test/attr/attr_dynamic.swift
+++ b/test/attr/attr_dynamic.swift
@@ -11,20 +11,20 @@ dynamic prefix operator +!+  // expected-error{{unexpected attribute 'dynamic' i
 
 class Foo {
   @objc dynamic init() {}
-  @objc dynamic init(x: NotObjCAble) {} // expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
+  @objc dynamic init(x: NotObjCAble) {} // expected-error{{initializer cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
   
   @objc dynamic var x: Int
   
-  @objc dynamic var nonObjcVar: NotObjCAble // expected-error{{property cannot be marked @objc because its type cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
+  @objc dynamic var nonObjcVar: NotObjCAble // expected-error{{property cannot be marked '@objc' because its type cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
 
   @objc dynamic func foo(x: Int) {}
   @objc dynamic func bar(x: Int) {}
 
-  @objc dynamic func nonObjcFunc(x: NotObjCAble) {} // expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
+  @objc dynamic func nonObjcFunc(x: NotObjCAble) {} // expected-error{{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
   
   @objc dynamic subscript(x: Int) -> ObjCClass { get {} }
 
-  @objc dynamic subscript(x: Int) -> NotObjCAble { get {} } // expected-error{{subscript cannot be marked @objc because its type cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
+  @objc dynamic subscript(x: Int) -> NotObjCAble { get {} } // expected-error{{subscript cannot be marked '@objc' because its type cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
   
   dynamic deinit {} // expected-error{{'dynamic' modifier cannot be applied to this declaration}} {{3-11=}}
 
diff --git a/test/attr/attr_dynamic_callable.swift b/test/attr/attr_dynamic_callable.swift
index 5a2d0a6eafae3..5317ba490f2c7 100644
--- a/test/attr/attr_dynamic_callable.swift
+++ b/test/attr/attr_dynamic_callable.swift
@@ -98,7 +98,7 @@ func testFunction(a: CallableReturningFunction) {
 //===----------------------------------------------------------------------===//
 
 // Arguments' type may not be variadic.
-// expected-error @+1 {{@dynamicCallable attribute requires 'Invalid1' to have either a valid 'dynamicallyCall(withArguments:)' method or 'dynamicallyCall(withKeywordArguments:)' method}} {{documentation-file=dynamic-callable-requirements}}
+// expected-error @+1 {{'@dynamicCallable' requires 'Invalid1' to have either a valid 'dynamicallyCall(withArguments:)' method or 'dynamicallyCall(withKeywordArguments:)' method}} {{documentation-file=dynamic-callable-requirements}}
 @dynamicCallable
 struct Invalid1 {
   func dynamicallyCall(withArguments arguments: [Int]...) -> Int {
@@ -107,7 +107,7 @@ struct Invalid1 {
 }
 
 // Keyword arguments' key type must be ExpressibleByStringLiteral.
-// expected-error @+1 {{@dynamicCallable attribute requires 'Invalid2' to have either a valid 'dynamicallyCall(withArguments:)' method or 'dynamicallyCall(withKeywordArguments:)' method}} {{documentation-file=dynamic-callable-requirements}}
+// expected-error @+1 {{'@dynamicCallable' requires 'Invalid2' to have either a valid 'dynamicallyCall(withArguments:)' method or 'dynamicallyCall(withKeywordArguments:)' method}} {{documentation-file=dynamic-callable-requirements}}
 @dynamicCallable
 struct Invalid2 {
   func dynamicallyCall(
@@ -128,8 +128,8 @@ protocol NoKeywordProtocol {
 }
 
 func testInvalidKeywordCall(x: NoKeyword, y: NoKeywordProtocol & AnyObject) {
-  x(a: 1, b: 2) // expected-error {{@dynamicCallable type 'NoKeyword' cannot be applied with keyword arguments; missing 'dynamicCall(withKeywordArguments:)' method}} {{documentation-file=dynamic-callable-requirements}}
-  y(a: 1, b: 2) // expected-error {{@dynamicCallable type 'any NoKeywordProtocol & AnyObject' cannot be applied with keyword arguments; missing 'dynamicCall(withKeywordArguments:)' method}} {{documentation-file=dynamic-callable-requirements}}
+  x(a: 1, b: 2) // expected-error {{'@dynamicCallable' type 'NoKeyword' cannot be applied with keyword arguments; missing 'dynamicCall(withKeywordArguments:)' method}} {{documentation-file=dynamic-callable-requirements}}
+  y(a: 1, b: 2) // expected-error {{'@dynamicCallable' type 'any NoKeywordProtocol & AnyObject' cannot be applied with keyword arguments; missing 'dynamicCall(withKeywordArguments:)' method}} {{documentation-file=dynamic-callable-requirements}}
 }
 
 // expected-error @+1 {{'@dynamicCallable' attribute cannot be applied to this declaration}}
@@ -147,7 +147,7 @@ func NotAllowedOnFunc() {}
 // @dynamicCallable cannot be declared on a base class and fulfilled with a
 // derived class.
 
-// expected-error @+1 {{@dynamicCallable attribute requires 'InvalidBase' to have either a valid 'dynamicallyCall(withArguments:)' method or 'dynamicallyCall(withKeywordArguments:)' method}}
+// expected-error @+1 {{'@dynamicCallable' requires 'InvalidBase' to have either a valid 'dynamicallyCall(withArguments:)' method or 'dynamicallyCall(withKeywordArguments:)' method}}
 @dynamicCallable
 class InvalidBase {}
 
diff --git a/test/attr/attr_dynamic_member_lookup.swift b/test/attr/attr_dynamic_member_lookup.swift
index 19445b6e2407c..1f6b83a6b728f 100644
--- a/test/attr/attr_dynamic_member_lookup.swift
+++ b/test/attr/attr_dynamic_member_lookup.swift
@@ -1,4 +1,5 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature KeyPathWithMethodMembers
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature KeyPathWithMethodMembers -verify-additional-prefix non-resilient-
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature KeyPathWithMethodMembers -enable-library-evolution -verify-additional-prefix resilient-
 // REQUIRES: swift_feature_KeyPathWithMethodMembers
 
 var global = 42
@@ -141,7 +142,7 @@ func testIUOResult(x: IUOResult) {
 // Subscript index must be ExpressibleByStringLiteral.
 @dynamicMemberLookup
 struct Invalid1 {
-  // expected-error @+1 {{@dynamicMemberLookup attribute requires 'Invalid1' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
+  // expected-error @+1 {{'@dynamicMemberLookup' requires 'Invalid1' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
   subscript(dynamicMember member: Int) -> Int {
     return 42
   }
@@ -150,7 +151,7 @@ struct Invalid1 {
 // Subscript may not be variadic.
 @dynamicMemberLookup
 struct Invalid2 {
-  // expected-error @+1 {{@dynamicMemberLookup attribute requires 'Invalid2' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
+  // expected-error @+1 {{'@dynamicMemberLookup' requires 'Invalid2' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
   subscript(dynamicMember member: String...) -> Int {
     return 42
   }
@@ -189,7 +190,7 @@ func NotAllowedOnFunc() {}
 // @dynamicMemberLookup cannot be declared on a base class and fulfilled with a
 // derived class.
 
-// expected-error @+1 {{@dynamicMemberLookup attribute requires 'InvalidBase' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
+// expected-error @+1 {{'@dynamicMemberLookup' requires 'InvalidBase' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
 @dynamicMemberLookup
 class InvalidBase {}
 
@@ -198,6 +199,97 @@ class InvalidDerived : InvalidBase { subscript(dynamicMember: String) -> Int { g
 // expected-error @+1 {{value of type 'InvalidDerived' has no member 'dynamicallyLookedUp'}}
 _ = InvalidDerived().dynamicallyLookedUp
 
+//===----------------------------------------------------------------------===//
+// Access level
+//===----------------------------------------------------------------------===//
+
+@dynamicMemberLookup
+public struct Accessible1 {
+  public subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+private struct Accessible2 {
+  fileprivate subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+open class Accessible3 {
+  public subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+open class Accessible4 {
+  open subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+public struct Accessible5 {
+  subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+
+  public subscript(dynamicMember member: StaticString) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+public struct Inaccessible1 {
+  // expected-non-resilient-warning @+2 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type; this will be an error in a future Swift language mode}}{{3-3=public }}
+  // expected-resilient-error @+1 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type}}{{3-3=public }}
+  subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+public struct Inaccessible2 {
+  // expected-non-resilient-warning @+2 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type; this will be an error in a future Swift language mode}}{{21-29=public}}
+  // expected-resilient-error @+1 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type}}{{21-29=public}}
+  @usableFromInline internal subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+internal struct Inaccessible3 {
+  // expected-non-resilient-warning @+2 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type; this will be an error in a future Swift language mode}}{{3-10=internal}}
+  // expected-resilient-error @+1 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type}}{{3-10=internal}}
+  private subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+private struct Inaccessible4 {
+  // expected-non-resilient-warning @+2 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type; this will be an error in a future Swift language mode}}{{3-10=fileprivate}}
+  // expected-resilient-error @+1 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type}}{{3-10=fileprivate}}
+  private subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+public struct Inaccessible5 {
+  internal struct Nested { }
+  var nested: Nested
+
+  // expected-non-resilient-warning @+2 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type; this will be an error in a future Swift language mode}}{{3-11=public}}
+  // expected-resilient-error @+1 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type}}{{3-11=public}}
+  internal subscript<Value>(dynamicMember keyPath: KeyPath<Nested, Value>) -> Value {
+    nested[keyPath: keyPath]
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // Existentials
 //===----------------------------------------------------------------------===//
@@ -789,20 +881,20 @@ do {
 
 @dynamicMemberLookup
 struct S1_52957 {
-  subscript(dynamicMember: String) -> String { // expected-error {{@dynamicMemberLookup attribute requires 'S1_52957' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
-  // expected-note@-1 {{add an explicit argument label to this subscript to satisfy the @dynamicMemberLookup requirement}}{{13-13=dynamicMember }}
+  subscript(dynamicMember: String) -> String { // expected-error {{'@dynamicMemberLookup' requires 'S1_52957' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
+  // expected-note@-1 {{add an explicit argument label to this subscript to satisfy the '@dynamicMemberLookup' requirement}}{{13-13=dynamicMember }}
     fatalError()
   }
 }
 
 @dynamicMemberLookup
 struct S2_52957 {
-  subscript(foo bar: String) -> String { // expected-error {{@dynamicMemberLookup attribute requires 'S2_52957' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
+  subscript(foo bar: String) -> String { // expected-error {{'@dynamicMemberLookup' requires 'S2_52957' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
     fatalError()
   }
 
-  subscript(foo: String) -> String { // expected-error {{@dynamicMemberLookup attribute requires 'S2_52957' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
-  // expected-note@-1 {{add an explicit argument label to this subscript to satisfy the @dynamicMemberLookup requirement}} {{13-13=dynamicMember }}
+  subscript(foo: String) -> String { // expected-error {{'@dynamicMemberLookup' requires 'S2_52957' to have a 'subscript(dynamicMember:)' method that accepts either 'ExpressibleByStringLiteral' or a key path}}
+  // expected-note@-1 {{add an explicit argument label to this subscript to satisfy the '@dynamicMemberLookup' requirement}} {{13-13=dynamicMember }}
     fatalError()
   }
 }
@@ -897,3 +989,33 @@ struct WithSendable {
     get { false }
   }
 }
+
+// Make sure we enforce a limit on the number of chained dynamic member lookups.
+@dynamicMemberLookup
+struct SelfRecursiveLookup<T> {
+  init(_: () -> T) {}
+  init(_: () -> KeyPath<Self, T>) {}
+  subscript<U>(dynamicMember kp: KeyPath<T, U>) -> SelfRecursiveLookup<U> {}
+}
+let selfRecurse1 = SelfRecursiveLookup { selfRecurse1.e }
+// expected-error@-1 {{could not find member 'e'; exceeded the maximum number of nested dynamic member lookups}}
+
+let selfRecurse2 = SelfRecursiveLookup { selfRecurse2[a: 0] }
+// expected-error@-1 {{could not find member 'subscript'; exceeded the maximum number of nested dynamic member lookups}}
+
+let selfRecurse3 = SelfRecursiveLookup { \.e }
+// expected-error@-1 {{could not find member 'e'; exceeded the maximum number of nested dynamic member lookups}}
+
+let selfRecurse4 = SelfRecursiveLookup { \.[a: 0] }
+// expected-error@-1 {{could not find member 'subscript'; exceeded the maximum number of nested dynamic member lookups}}
+
+extension SelfRecursiveLookup where T == SelfRecursiveLookup<SelfRecursiveLookup<SelfRecursiveLookup<Int>>> {
+  var terminator: T { fatalError() }
+  subscript(terminator terminator: Int) -> T { fatalError() }
+}
+
+let selfRecurse5 = SelfRecursiveLookup { selfRecurse5.terminator }
+let selfRecurse6 = SelfRecursiveLookup { selfRecurse6[terminator: 0] }
+
+let selfRecurse7 = SelfRecursiveLookup { \.terminator }
+let selfRecurse8 = SelfRecursiveLookup { \.[terminator: 0] }
diff --git a/test/attr/attr_dynamic_member_lookup_swift7.swift b/test/attr/attr_dynamic_member_lookup_swift7.swift
new file mode 100644
index 0000000000000..fbe1118d41b97
--- /dev/null
+++ b/test/attr/attr_dynamic_member_lookup_swift7.swift
@@ -0,0 +1,73 @@
+// RUN: %target-typecheck-verify-swift -swift-version 7
+// REQUIRES: swift7
+
+@dynamicMemberLookup
+public struct Accessible1 {
+  public subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+private struct Accessible2 {
+  fileprivate subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+open class Accessible3 {
+  public subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+open class Accessible4 {
+  open subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+public struct Accessible5 {
+  subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+
+  public subscript(dynamicMember member: StaticString) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+public struct Inaccessible1 {
+  // expected-error @+1 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type}}{{3-3=public }}
+  subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+public struct Inaccessible2 {
+  // expected-error @+1 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type}}{{21-29=public}}
+  @usableFromInline internal subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+internal struct Inaccessible3 {
+  // expected-error @+1 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type}}{{3-10=internal}}
+  private subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
+
+@dynamicMemberLookup
+private struct Inaccessible4 {
+  // expected-error @+1 {{'@dynamicMemberLookup' requires 'subscript(dynamicMember:)' to be as accessible as its enclosing type}}{{3-10=fileprivate}}
+  private subscript(dynamicMember member: String) -> Int {
+    return 42
+  }
+}
diff --git a/test/attr/attr_escaping.swift b/test/attr/attr_escaping.swift
index 838992f86f751..2286d0efbce4c 100644
--- a/test/attr/attr_escaping.swift
+++ b/test/attr/attr_escaping.swift
@@ -3,7 +3,7 @@
 @escaping var fn : () -> Int = { 4 }  // expected-error {{attribute can only be applied to types, not declarations}}
 func paramDeclEscaping(@escaping fn: (Int) -> Void) {} // expected-error {{attribute can only be applied to types, not declarations}}
 
-func wrongParamType(a: @escaping Int) {} // expected-error {{@escaping attribute only applies to function types}}
+func wrongParamType(a: @escaping Int) {} // expected-error {{'@escaping' only applies to function types}}
 
 func conflictingAttrs(_ fn: @noescape @escaping () -> Int) {} // expected-error {{unknown attribute 'noescape'}}
 
@@ -12,7 +12,7 @@ func takesEscaping(_ fn: @escaping () -> Int) {} // ok
 func callEscapingWithNoEscape(_ fn: () -> Int) {
   // expected-note@-1{{parameter 'fn' is implicitly non-escaping}} {{37-37=@escaping }}
 
-  takesEscaping(fn) // expected-error{{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  takesEscaping(fn) // expected-error{{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 
   // This is a non-escaping use:
   let _ = fn
@@ -22,7 +22,7 @@ typealias IntSugar = Int
 func callSugared(_ fn: () -> IntSugar) {
   // expected-note@-1{{parameter 'fn' is implicitly non-escaping}} {{24-24=@escaping }}
 
-  takesEscaping(fn) // expected-error{{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  takesEscaping(fn) // expected-error{{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 }
 
 struct StoresClosure {
@@ -30,29 +30,29 @@ struct StoresClosure {
   init(_ fn: () -> Int) {
     // expected-note@-1{{parameter 'fn' is implicitly non-escaping}} {{14-14=@escaping }}
 
-    closure = fn // expected-error{{assigning non-escaping parameter 'fn' to an @escaping closure}}
+    closure = fn // expected-error{{assigning non-escaping parameter 'fn' to an '@escaping' closure}}
   }
 
   func arrayPack(_ fn: () -> Int) -> [() -> Int] {
     // expected-note@-1{{parameter 'fn' is implicitly non-escaping}} {{24-24=@escaping }}
 
-    return [fn] // expected-error{{using non-escaping parameter 'fn' in a context expecting an @escaping closure}}
+    return [fn] // expected-error{{using non-escaping parameter 'fn' in a context expecting an '@escaping' closure}}
   }
 
   func dictPack(_ fn: () -> Int) -> [String: () -> Int] {
     // expected-note@-1{{parameter 'fn' is implicitly non-escaping}} {{23-23=@escaping }}
-    return ["ultimate answer": fn] // expected-error{{using non-escaping parameter 'fn' in a context expecting an @escaping closure}}
+    return ["ultimate answer": fn] // expected-error{{using non-escaping parameter 'fn' in a context expecting an '@escaping' closure}}
   }
 
   func autoclosureDictPack(_ fn: @autoclosure () -> Int) -> [String: () -> Int] {
     // expected-note@-1{{parameter 'fn' is implicitly non-escaping}} {{46-46= @escaping}}
-    return ["ultimate answer": fn] // expected-error{{using non-escaping parameter 'fn' in a context expecting an @escaping closure}}
+    return ["ultimate answer": fn] // expected-error{{using non-escaping parameter 'fn' in a context expecting an '@escaping' closure}}
   }
 
   func arrayPack(_ fn: @escaping () -> Int, _ fn2 : () -> Int) -> [() -> Int] {
     // expected-note@-1{{parameter 'fn2' is implicitly non-escaping}} {{53-53=@escaping }}
 
-    return [fn, fn2] // expected-error{{using non-escaping parameter 'fn2' in a context expecting an @escaping closure}}
+    return [fn, fn2] // expected-error{{using non-escaping parameter 'fn2' in a context expecting an '@escaping' closure}}
   }
 }
 
@@ -62,7 +62,7 @@ func takesEscapingBlock(_ fn: @escaping @convention(block) () -> Void) {
 func callEscapingWithNoEscapeBlock(_ fn: () -> Void) {
   // expected-note@-1{{parameter 'fn' is implicitly non-escaping}} {{42-42=@escaping }}
 
-  takesEscapingBlock(fn) // expected-error{{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  takesEscapingBlock(fn) // expected-error{{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 }
 
 func takesEscapingAutoclosure(_ fn: @autoclosure @escaping () -> Int) {}
@@ -71,28 +71,28 @@ func callEscapingAutoclosureWithNoEscape(_ fn: () -> Int) {
   takesEscapingAutoclosure(1+1)
 }
 
-let foo: @escaping (Int) -> Int // expected-error{{@escaping attribute may only be used in function parameter position}} {{10-20=}}
+let foo: @escaping (Int) -> Int // expected-error{{'@escaping' may only be used in function parameter position}} {{10-20=}}
 
 struct GenericStruct<T> {}
 
-func misuseEscaping(_ a: @escaping Int) {} // expected-error{{@escaping attribute only applies to function types}} {{26-36=}}
-func misuseEscaping(_ a: (@escaping Int)?) {} // expected-error{{@escaping attribute only applies to function types}} {{27-36=}}
+func misuseEscaping(_ a: @escaping Int) {} // expected-error{{'@escaping' only applies to function types}} {{26-36=}}
+func misuseEscaping(_ a: (@escaping Int)?) {} // expected-error{{'@escaping' only applies to function types}} {{27-36=}}
 func misuseEscaping(opt a: @escaping ((Int) -> Int)?) {} // expected-error{{closure is already escaping in optional type argument}} {{28-38=}}
 
 func misuseEscaping(_ a: (@escaping (Int) -> Int)?) {} // expected-error{{closure is already escaping in optional type argument}} {{27-36=}}
 func misuseEscaping(nest a: (((@escaping (Int) -> Int))?)) {} // expected-error{{closure is already escaping in optional type argument}} {{32-41=}}
 func misuseEscaping(iuo a: (@escaping (Int) -> Int)!) {} // expected-error{{closure is already escaping in optional type argument}} {{29-38=}}
 
-func misuseEscaping(_ a: Optional<@escaping (Int) -> Int>, _ b: Int) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{35-44=}}
-func misuseEscaping(_ a: (@escaping (Int) -> Int, Int)) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{27-36=}}
-func misuseEscaping(_ a: [@escaping (Int) -> Int]) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{27-36=}}
-func misuseEscaping(_ a: [@escaping (Int) -> Int]?) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{27-36=}}
-func misuseEscaping(_ a: [Int : @escaping (Int) -> Int]) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{33-43=}}
-func misuseEscaping(_ a: GenericStruct<@escaping (Int) -> Int>) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{40-49=}}
+func misuseEscaping(_ a: Optional<@escaping (Int) -> Int>, _ b: Int) {} // expected-error{{'@escaping' may only be used in function parameter position}} {{35-44=}}
+func misuseEscaping(_ a: (@escaping (Int) -> Int, Int)) {} // expected-error{{'@escaping' may only be used in function parameter position}} {{27-36=}}
+func misuseEscaping(_ a: [@escaping (Int) -> Int]) {} // expected-error{{'@escaping' may only be used in function parameter position}} {{27-36=}}
+func misuseEscaping(_ a: [@escaping (Int) -> Int]?) {} // expected-error{{'@escaping' may only be used in function parameter position}} {{27-36=}}
+func misuseEscaping(_ a: [Int : @escaping (Int) -> Int]) {} // expected-error{{'@escaping' may only be used in function parameter position}} {{33-43=}}
+func misuseEscaping(_ a: GenericStruct<@escaping (Int) -> Int>) {} // expected-error{{'@escaping' may only be used in function parameter position}} {{40-49=}}
 
 func takesEscapingGeneric<T>(_ fn: @escaping () -> T) {}
 func callEscapingGeneric<T>(_ fn: () -> T) { // expected-note {{parameter 'fn' is implicitly non-escaping}} {{35-35=@escaping }}
-  takesEscapingGeneric(fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  takesEscapingGeneric(fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 }
 
 
@@ -101,29 +101,29 @@ class Sub: Super {}
 
 func takesEscapingSuper(_ fn: @escaping () -> Super) {}
 func callEscapingSuper(_ fn: () -> Sub) { // expected-note {{parameter 'fn' is implicitly non-escaping}} {{30-30=@escaping }}
-  takesEscapingSuper(fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  takesEscapingSuper(fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 }
 
 func takesEscapingSuperGeneric<T: Super>(_ fn: @escaping () -> T) {}
 func callEscapingSuperGeneric(_ fn: () -> Sub) { // expected-note {{parameter 'fn' is implicitly non-escaping}} {{37-37=@escaping }}
-  takesEscapingSuperGeneric(fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  takesEscapingSuperGeneric(fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 }
 func callEscapingSuperGeneric<T: Sub>(_ fn: () -> T) { // expected-note {{parameter 'fn' is implicitly non-escaping}} {{45-45=@escaping }}
-  takesEscapingSuperGeneric(fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  takesEscapingSuperGeneric(fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 }
 
 func testModuloOptionalness() {
   var iuoClosure: (() -> Void)! = nil
   func setIUOClosure(_ fn: () -> Void) { // expected-note {{parameter 'fn' is implicitly non-escaping}} {{28-28=@escaping }}
-    iuoClosure = fn // expected-error{{assigning non-escaping parameter 'fn' to an @escaping closure}}
+    iuoClosure = fn // expected-error{{assigning non-escaping parameter 'fn' to an '@escaping' closure}}
   }
   var iuoClosureExplicit: (() -> Void)!
   func setExplicitIUOClosure(_ fn: () -> Void) { // expected-note {{parameter 'fn' is implicitly non-escaping}} {{36-36=@escaping }}
-    iuoClosureExplicit = fn // expected-error{{assigning non-escaping parameter 'fn' to an @escaping closure}}
+    iuoClosureExplicit = fn // expected-error{{assigning non-escaping parameter 'fn' to an '@escaping' closure}}
   }
   var deepOptionalClosure: (() -> Void)???
   func setDeepOptionalClosure(_ fn: () -> Void) { // expected-note {{parameter 'fn' is implicitly non-escaping}} {{37-37=@escaping }}
-    deepOptionalClosure = fn // expected-error{{assigning non-escaping parameter 'fn' to an @escaping closure}}
+    deepOptionalClosure = fn // expected-error{{assigning non-escaping parameter 'fn' to an '@escaping' closure}}
   }
 }
 
@@ -138,15 +138,15 @@ func takesVarargsOfFunctions(fns: () -> ()...) {
   }
 }
 
-func takesVarargsOfFunctionsExplicitEscaping(fns: @escaping () -> ()...) {} // expected-error{{@escaping attribute may only be used in function parameter position}}
+func takesVarargsOfFunctionsExplicitEscaping(fns: @escaping () -> ()...) {} // expected-error{{'@escaping' may only be used in function parameter position}}
 
 func takesNoEscapeFunction(fn: () -> ()) { // expected-note {{parameter 'fn' is implicitly non-escaping}}
-  takesVarargsOfFunctions(fns: fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  takesVarargsOfFunctions(fns: fn) // expected-error {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
 }
 
 
 class FooClass {
-  var stored : Optional<(()->Int)->Void> = nil  // expected-note {{add explicit @escaping to function parameter #0}} {{26-26=@escaping }}
+  var stored : Optional<(()->Int)->Void> = nil  // expected-note {{add explicit '@escaping' to function parameter #0}} {{26-26=@escaping }}
   var computed : (()->Int)->Void {
     get { return stored! }
     set(newValue) { stored = newValue } // ok
@@ -231,19 +231,19 @@ extension P_52188 {
 
 // https://github.com/apple/swift/issues/51669
 
-func f_51669<T>(_ x: @escaping T) {} // expected-error 1{{@escaping attribute only applies to function types}}
+func f_51669<T>(_ x: @escaping T) {} // expected-error 1{{'@escaping' only applies to function types}}
 
 // https://github.com/apple/swift/issues/57070
 
 var global: ((() -> Void) -> Void)? = nil
-// expected-note@-1 {{add explicit @escaping to function parameter #0}} {{15-15=@escaping }}
+// expected-note@-1 {{add explicit '@escaping' to function parameter #0}} {{15-15=@escaping }}
 
 class C_57070 {
   let ok: (@escaping () -> Void) -> Void // OK
-  let callback: (() -> Void) -> Void // expected-note {{add explicit @escaping to function parameter #0}} {{18-18=@escaping }}
-  let callback1: (() -> Void, () -> Void) -> Void // expected-note {{add explicit @escaping to function parameter #1}} {{31-31=@escaping }} 
-  let callbackAuto: (@autoclosure () -> Void) -> Void // expected-note {{add explicit @escaping to function parameter #0}} {{34-34= @escaping}}
-  let callbackOpt: ((() -> Void) -> Void)? // expected-note{{add explicit @escaping to function parameter #0}} {{22-22=@escaping }}
+  let callback: (() -> Void) -> Void // expected-note {{add explicit '@escaping' to function parameter #0}} {{18-18=@escaping }}
+  let callback1: (() -> Void, () -> Void) -> Void // expected-note {{add explicit '@escaping' to function parameter #1}} {{31-31=@escaping }} 
+  let callbackAuto: (@autoclosure () -> Void) -> Void // expected-note {{add explicit '@escaping' to function parameter #0}} {{34-34= @escaping}}
+  let callbackOpt: ((() -> Void) -> Void)? // expected-note{{add explicit '@escaping' to function parameter #0}} {{22-22=@escaping }}
 
   init(f: @escaping (@escaping() -> Void) -> Void) {
     self.callback = f // expected-error{{cannot assign value of type '(@escaping () -> Void) -> Void' to type '(() -> Void) -> Void'}}
diff --git a/test/attr/attr_execution.swift b/test/attr/attr_execution.swift
deleted file mode 100644
index 9ee107a382121..0000000000000
--- a/test/attr/attr_execution.swift
+++ /dev/null
@@ -1,141 +0,0 @@
-// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple -enable-experimental-feature ExecutionAttribute
-
-// REQUIRES: concurrency
-// REQUIRES: swift_feature_ExecutionAttribute
-
-@execution(something) func invalidAttr() async {} // expected-error {{unknown option 'something' for attribute 'execution'}}
-
-@execution(concurrent) @execution(caller) func mutipleAttrs() async {}
-// expected-error@-1 {{duplicate attribute}} expected-note@-1 {{attribute already specified here}}
-
-do {
-  @execution(caller) struct S {}
-  // expected-error@-1 {{'@execution(caller)' attribute cannot be applied to this declaration}}
-
-  func f(@execution(caller) param: Int) {}
-  // expected-error@-1 {{'@execution(caller)' attribute cannot be applied to this declaration}}
-}
-
-@execution(concurrent) func nonAsync1() {}
-// expected-error@-1 {{cannot use '@execution' on non-async global function 'nonAsync1()'}}
-
-@execution(caller) func nonAsync2() {}
-// expected-error@-1 {{cannot use '@execution' on non-async global function 'nonAsync2()'}}
-
-@execution(concurrent) func testGlobal() async {} // Ok
-
-struct Test {
-  @execution(concurrent) init() {}
-  // expected-error@-1 {{cannot use '@execution' on non-async initializer 'init()'}}
-
-  @execution(concurrent) init(async: Void) async {}
-
-  @execution(concurrent) func member() {}
-  // expected-error@-1 {{cannot use '@execution' on non-async instance method 'member()'}}
-
-  @execution(concurrent) func member() async {} // Ok
-
-  @execution(concurrent) var syncP: Int {
-  // expected-error@-1 {{cannot use '@execution' on non-async property 'syncP'}}
-    get {}
-  }
-  @execution(concurrent) var asyncP: Int {
-    get async {}
-  }
-
-  // expected-error@+1 {{cannot use '@execution' on non-async subscript 'subscript(sync:)'}}
-  @execution(caller) subscript(sync _: Int) -> Bool {
-    @execution(concurrent) get { false }
-    // expected-error@-1 {{@execution(concurrent)' attribute cannot be applied to this declaration}}
-    @execution(concurrent) set { }
-    // expected-error@-1 {{@execution(concurrent)' attribute cannot be applied to this declaration}}
-  }
-  @execution(caller) subscript(async _: Int) -> Bool {
-    get async {}
-  }
-
-  @execution(caller) var storedVar: Int
-  // expected-error@-1 {{'@execution(caller)' must not be used on stored properties}}
-  @execution(caller) let storedLet: Int
-  // expected-error@-1 {{'@execution(caller)' must not be used on stored properties}}
-}
-
-do {
-  class C {
-    @execution(caller) deinit {}
-    // expected-error@-1 {{'@execution(caller)' attribute cannot be applied to this declaration}}
-  }
-}
-
-do {
-  @execution(caller) func local() async {} // Ok
-
-  protocol P {
-    @execution(caller) var syncP: Int { get }
-    // expected-error@-1 {{cannot use '@execution' on non-async property 'syncP'}}
-
-    @execution(caller) var asyncP: Int { get async }
-  }
-}
-
-struct TestAttributeCollisions {
-  @execution(concurrent) nonisolated func testNonIsolated() async {}
-
-  @execution(concurrent) func test(arg: isolated MainActor) async {}
-  // expected-error@-1 {{cannot use '@execution' on instance method 'test(arg:)' because it has an isolated parameter: 'arg'}}
-  @execution(concurrent) subscript(test arg: isolated MainActor) -> Int {
-  // expected-error@-1 {{cannot use '@execution' on subscript 'subscript(test:)' because it has an isolated parameter: 'arg'}}
-    get async {}
-  }
-
-  @execution(concurrent) func testIsolationAny(arg: @isolated(any) () -> Void) async {}
-  // expected-error@-1 {{cannot use '@execution' on instance method 'testIsolationAny(arg:)' because it has a dynamically isolated parameter: 'arg'}}
-  @execution(concurrent) subscript(testIsolationAny arg: @isolated(any) () -> Void) -> Int {
-  // expected-error@-1 {{cannot use '@execution' on subscript 'subscript(testIsolationAny:)' because it has a dynamically isolated parameter: 'arg'}}
-    get async {}
-  }
-
-  @MainActor @execution(concurrent) func testGlobalActor() async {}
-  // expected-warning @-1 {{instance method 'testGlobalActor()' has multiple actor-isolation attributes (@MainActor and @execution(concurrent))}}
-
-  @execution(caller) nonisolated func testNonIsolatedCaller() async {} // Ok
-  @MainActor @execution(caller) func testGlobalActorCaller() async {}
-  // expected-warning@-1 {{instance method 'testGlobalActorCaller()' has multiple actor-isolation attributes (@MainActor and @execution(caller))}}
-  @execution(caller) func testCaller(arg: isolated MainActor) async {}
-  // expected-error@-1 {{cannot use '@execution' on instance method 'testCaller(arg:)' because it has an isolated parameter: 'arg'}}
-  
-  @execution(concurrent) @Sendable func test(_: @Sendable () -> Void, _: sending Int) async {} // Ok
-  @execution(caller) @Sendable func testWithSendableCaller(_: @Sendable () -> Void, _: sending Int) async {} // Ok
-}
-
-@MainActor
-protocol P {
-  func test() async
-}
-
-struct InfersMainActor : P {
-  @execution(concurrent) func test() async {}
-}
-
-@MainActor
-struct IsolatedType {
-  @execution(concurrent) func test() async {}
-}
-
-_ = { @execution(caller) in // Ok
-}
-
-_ = { @execution(concurrent) in // Ok
-}
-
-_ = { @MainActor @execution(concurrent) in
-  // expected-error@-1 {{cannot use '@execution' because function type is isolated to a global actor 'MainActor'}}
-}
-
-_ = { @execution(concurrent) () -> Int in
-  // expected-error@-1 {{'@execution' on non-async closure}}
-}
-
-_ = { @execution(caller) (x: isolated (any Actor)?) in
-  // expected-error@-1 {{cannot use '@execution' together with an isolated parameter}}
-}
diff --git a/test/attr/attr_expose.swift b/test/attr/attr_expose.swift
index c09ba9ad2c45d..71209b4c548ac 100644
--- a/test/attr/attr_expose.swift
+++ b/test/attr/attr_expose.swift
@@ -12,22 +12,31 @@ func exposeWithoutArgs() {}
 @_expose(CplusPlus) // expected-error {{expected '_expose' option such as 'Cxx'}}
 func incorrectLangSpecifier() {}
 
-@_expose(Cxx) @_cdecl("test") // expected-error {{@_expose attribute cannot be applied to an '@_cdecl' declaration}}
+@_expose(Cxx) @_cdecl("test") // expected-error {{'@_expose' cannot be applied to an '@_cdecl' declaration}}
 func cdeclAndExpose() {}
 
+@_expose(Cxx) @_expose(!Cxx)  // expected-error {{'@_expose' cannot be applied to an '@_expose(Cxx)' declaration}}
+func contradictingExpose() {}
+
+@_expose(!Cxx) @_expose(Cxx)  // expected-error {{'@_expose' cannot be applied to an '@_expose(Cxx)' declaration}}
+func contradictingExpose2() {}
+
+@_expose(!Cxx, "name")  // expected-error {{'@_expose(!Cxx)' does not accept a name argument}}
+func notExposeWithName() {}
+
 func hasNested() {
   @_expose(Cxx) // expected-error{{can only be used in a non-local scope}}
   func nested() { }
 }
 
 struct NotExposedStruct {
-    @_expose(Cxx) // expected-error {{@_expose attribute cannot be applied inside of unexposed declaration 'NotExposedStruct'}}
+    @_expose(Cxx) // expected-error {{'@_expose' cannot be applied inside of unexposed declaration 'NotExposedStruct'}}
     func errorOnInnerExpose() {}
 }
 
 @_expose(Cxx)
 struct ExposedStruct {
-    @_expose(Cxx, "create") // expected-error {{invalid declaration name 'create' specified in an @_expose attribute; exposed initializer name must start with 'init'}}
+    @_expose(Cxx, "create") // expected-error {{invalid declaration name 'create' specified in '@_expose'; exposed initializer name must start with 'init'}}
     init() {}
 
     @_expose(Cxx, "initWith")
@@ -41,8 +50,8 @@ func exposeToCxxCxx() {}
 @_expose(wasm, "with_name") func wasmName() {}
 @_expose(wasm, "") func wasmEmptyNameOk() {}
 
-@_expose(wasm) struct WasmErrorOnStruct { // expected-error {{@_expose attribute with 'wasm' can only be applied to global functions}}
-  @_expose(wasm) func errorOnMethod() {} // expected-error {{@_expose attribute with 'wasm' can only be applied to global functions}}
+@_expose(wasm) struct WasmErrorOnStruct { // expected-error {{'@_expose' with 'wasm' can only be applied to global functions}}
+  @_expose(wasm) func errorOnMethod() {} // expected-error {{'@_expose' with 'wasm' can only be applied to global functions}}
 }
 
 func wasmNested() {
diff --git a/test/attr/attr_extern.swift b/test/attr/attr_extern.swift
index c84def8737c77..9dd44298b137f 100644
--- a/test/attr/attr_extern.swift
+++ b/test/attr/attr_extern.swift
@@ -57,10 +57,10 @@ func emptyCName()
 @_extern(c, "0start_with_digit")
 func explicitDigitPrefixed()
 
-@_extern(c) // expected-warning {{C name '+' may be invalid; explicitly specify the name in @_extern(c) to suppress this warning}}
+@_extern(c) // expected-warning {{C name '+' may be invalid; explicitly specify the name in '@_extern(c)' to suppress this warning}}
 func +(a: Int, b: Bool) -> Bool
 
-@_extern(c) // expected-warning {{C name '🥸_implicitInvalid' may be invalid; explicitly specify the name in @_extern(c) to suppress this warning}}
+@_extern(c) // expected-warning {{C name '🥸_implicitInvalid' may be invalid; explicitly specify the name in '@_extern(c)' to suppress this warning}}
 func 🥸_implicitInvalid()
 
 @_extern(c)
diff --git a/test/attr/attr_extern_fixit.swift b/test/attr/attr_extern_fixit.swift
index a247b5f63c968..8770bea429949 100644
--- a/test/attr/attr_extern_fixit.swift
+++ b/test/attr/attr_extern_fixit.swift
@@ -1,7 +1,6 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature Extern -emit-fixits-path %t.remap -fixit-all
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature Extern
 
 // REQUIRES: swift_feature_Extern
 
-@_extern(c) // expected-warning {{C name '+' may be invalid; explicitly specify the name in @_extern(c) to suppress this warning}}
+@_extern(c) // expected-warning {{C name '+' may be invalid; explicitly specify the name in '@_extern(c)' to suppress this warning}}{{11-11=, "+"}}{{none}}
 func +(a: Int, b: Bool) -> Bool
diff --git a/test/attr/attr_extern_fixit.swift.result b/test/attr/attr_extern_fixit.swift.result
deleted file mode 100644
index df3ac227ca269..0000000000000
--- a/test/attr/attr_extern_fixit.swift.result
+++ /dev/null
@@ -1,7 +0,0 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature Extern -emit-fixits-path %t.remap -fixit-all
-// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
-
-// REQUIRES: swift_feature_Extern
-
-@_extern(c, "+") // expected-warning {{C name '+' may be invalid; explicitly specify the name in @_extern(c) to suppress this warning}}
-func +(a: Int, b: Bool) -> Bool
diff --git a/test/attr/attr_ibaction.swift b/test/attr/attr_ibaction.swift
index 97398b913ee57..d6ede373e82ae 100644
--- a/test/attr/attr_ibaction.swift
+++ b/test/attr/attr_ibaction.swift
@@ -102,14 +102,14 @@ extension String: @retroactive _ObjectiveCBridgeable {
   @IBAction func action6a(_: Any!) {}
 
   // Protocol types
-  @IBAction func action7(_: P1) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
-  @IBAction func action8(_: CP1) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
+  @IBAction func action7(_: P1) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
+  @IBAction func action8(_: CP1) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
   @IBAction func action9(_: OP1) {}
-  @IBAction func action10(_: P1?) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
-  @IBAction func action11(_: CP1?) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action10(_: P1?) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action11(_: CP1?) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
   @IBAction func action12(_: OP1?) {}
-  @IBAction func action13(_: P1!) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
-  @IBAction func action14(_: CP1!) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action13(_: P1!) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action14(_: CP1!) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
   @IBAction func action15(_: OP1!) {}
 
   // Class metatype
@@ -123,26 +123,26 @@ extension String: @retroactive _ObjectiveCBridgeable {
   @IBAction func action20(_: AnyClass!) {}
 
   // Protocol types
-  @IBAction func action21(_: P1.Type) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
-  @IBAction func action22(_: CP1.Type) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action21(_: P1.Type) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action22(_: CP1.Type) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
   @IBAction func action23(_: OP1.Type) {}
-  @IBAction func action24(_: P1.Type?) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
-  @IBAction func action25(_: CP1.Type?) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action24(_: P1.Type?) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action25(_: CP1.Type?) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
   @IBAction func action26(_: OP1.Type?) {}
-  @IBAction func action27(_: P1.Type!) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
-  @IBAction func action28(_: CP1.Type!) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action27(_: P1.Type!) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action28(_: CP1.Type!) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
   @IBAction func action29(_: OP1.Type!) {}
 
   // Structs representable in Objective-C
   @IBAction func action32(_: Int) {}
-  @IBAction func action33(_: Int?) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
+  @IBAction func action33(_: Int?) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
 
   @IBAction func action34(_: String) {}
   @IBAction func action35(_: String?) {}
 
   // Other bad cases
-  @IBAction func action30(_: S) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
-  @IBAction func action31(_: E) {} // expected-error{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
+  @IBAction func action30(_: S) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
+  @IBAction func action31(_: E) {} // expected-error{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
 
   init() { }
 }
diff --git a/test/attr/attr_iboutlet.swift b/test/attr/attr_iboutlet.swift
index d797fd7a44e38..5521258fda506 100644
--- a/test/attr/attr_iboutlet.swift
+++ b/test/attr/attr_iboutlet.swift
@@ -3,7 +3,7 @@
 // REQUIRES: objc_interop
 import Foundation
 
-// expected-error@+1 {{@IBOutlet property cannot have non-object type 'Int'}}
+// expected-error@+1 {{'@IBOutlet' property cannot have non-object type 'Int'}}
 @IBOutlet // expected-error {{only class instance properties can be declared @IBOutlet}} {{1-11=}}
 var iboutlet_global: Int?
 
@@ -28,10 +28,10 @@ class IBOutletWrapperTy {
   @IBOutlet // expected-error {{@IBOutlet may only be used on 'var' declarations}} {{3-13=}}
   func click() -> () {}
 
-  @IBOutlet // expected-error {{@IBOutlet attribute requires property to be mutable}} {{3-13=}}
+  @IBOutlet // expected-error {{'@IBOutlet' requires property to be mutable}} {{3-13=}}
   let immutable: IBOutletWrapperTy? = nil
 
-  @IBOutlet // expected-error {{@IBOutlet attribute requires property to be mutable}} {{3-13=}}
+  @IBOutlet // expected-error {{'@IBOutlet' requires property to be mutable}} {{3-13=}}
   var computedImmutable: IBOutletWrapperTy? {
     return nil
   }
@@ -57,8 +57,8 @@ class NonObjC {}
   @IBOutlet var outlet2: X?
   @IBOutlet var outlet3: X!
 
-  @IBOutlet var outlet2a: NonObjC? // expected-error{{@IBOutlet property cannot have non-'@objc' class type 'NonObjC'}} {{3-13=}}
-  @IBOutlet var outlet3a: NonObjC! // expected-error{{@IBOutlet property cannot have non-'@objc' class type 'NonObjC'}} {{3-13=}}
+  @IBOutlet var outlet2a: NonObjC? // expected-error{{'@IBOutlet' property cannot have non-'@objc' class type 'NonObjC'}} {{3-13=}}
+  @IBOutlet var outlet3a: NonObjC! // expected-error{{'@IBOutlet' property cannot have non-'@objc' class type 'NonObjC'}} {{3-13=}}
 
   // AnyObject
   @IBOutlet var outlet5: AnyObject?
@@ -69,38 +69,38 @@ class NonObjC {}
   @IBOutlet var outlet6a: Any!
 
   // Protocol types
-  @IBOutlet var outlet10: P1? // expected-error{{@IBOutlet property cannot have non-'@objc' protocol type}} {{3-13=}}
-  @IBOutlet var outlet11: CP1? // expected-error{{@IBOutlet property cannot have non-'@objc' protocol type}} {{3-13=}}
+  @IBOutlet var outlet10: P1? // expected-error{{'@IBOutlet' property cannot have non-'@objc' protocol type}} {{3-13=}}
+  @IBOutlet var outlet11: CP1? // expected-error{{'@IBOutlet' property cannot have non-'@objc' protocol type}} {{3-13=}}
   @IBOutlet var outlet12: OP1?
-  @IBOutlet var outlet13: P1! // expected-error{{@IBOutlet property cannot have non-'@objc' protocol type}} {{3-13=}}
-  @IBOutlet var outlet14: CP1! // expected-error{{@IBOutlet property cannot have non-'@objc' protocol type}} {{3-13=}}
+  @IBOutlet var outlet13: P1! // expected-error{{'@IBOutlet' property cannot have non-'@objc' protocol type}} {{3-13=}}
+  @IBOutlet var outlet14: CP1! // expected-error{{'@IBOutlet' property cannot have non-'@objc' protocol type}} {{3-13=}}
   @IBOutlet var outlet15: OP1!
 
   // Class metatype
-  @IBOutlet var outlet16: X.Type? // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet17: X.Type! // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet16: X.Type? // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet17: X.Type! // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
 
   // AnyClass
-  @IBOutlet var outlet19: AnyClass? // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet20: AnyClass! // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet19: AnyClass? // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet20: AnyClass! // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
 
   // Protocol metatype types
-  @IBOutlet var outlet24: P1.Type? // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet25: CP1.Type? // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet26: OP1.Type? // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet27: P1.Type! // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet28: CP1.Type! // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet29: OP1.Type! // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet24: P1.Type? // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet25: CP1.Type? // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet26: OP1.Type? // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet27: P1.Type! // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet28: CP1.Type! // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet29: OP1.Type! // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
   
   // String
   @IBOutlet var outlet33: String?
   @IBOutlet var outlet34: String!
 
   // Other bad cases
-  @IBOutlet var outlet35: S? // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet36: E? // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet37: (X, X)? // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
-  @IBOutlet var outlet38: Int? // expected-error{{@IBOutlet property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet35: S? // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet36: E? // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet37: (X, X)? // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
+  @IBOutlet var outlet38: Int? // expected-error{{'@IBOutlet' property cannot have non-object type}} {{3-13=}}
 
   @IBOutlet var collection1b: [AnyObject]?
   @IBOutlet var collection1c: [AnyObject]!
@@ -111,21 +111,21 @@ class NonObjC {}
   @IBOutlet var collection3b: [OP1]?
   @IBOutlet var collection3c: [OP1]!
 
-  @IBOutlet var collection4b: ([CP1])? // expected-error{{@IBOutlet property cannot be an array of non-'@objc' protocol type}} {{3-13=}}
-  @IBOutlet var collection4c: ([CP1])! // expected-error{{@IBOutlet property cannot be an array of non-'@objc' protocol type}} {{3-13=}}
+  @IBOutlet var collection4b: ([CP1])? // expected-error{{'@IBOutlet' property cannot be an array of non-'@objc' protocol type}} {{3-13=}}
+  @IBOutlet var collection4c: ([CP1])! // expected-error{{'@IBOutlet' property cannot be an array of non-'@objc' protocol type}} {{3-13=}}
 
   @IBOutlet var collection5b: ([String])?
   @IBOutlet var collection5c: ([String])!
 
-  @IBOutlet var collection6b: ([NonObjC])? // expected-error{{@IBOutlet property cannot be an array of non-'@objc' class type}} {{3-13=}}
-  @IBOutlet var collection6c: ([NonObjC])! // expected-error{{@IBOutlet property cannot be an array of non-'@objc' class type}} {{3-13=}}
+  @IBOutlet var collection6b: ([NonObjC])? // expected-error{{'@IBOutlet' property cannot be an array of non-'@objc' class type}} {{3-13=}}
+  @IBOutlet var collection6c: ([NonObjC])! // expected-error{{'@IBOutlet' property cannot be an array of non-'@objc' class type}} {{3-13=}}
 
   init() { }
 }
 
 // Check that the type is optional
 @objc class OX {
-  // expected-error@+3 {{@IBOutlet property has non-optional type 'OX'}}
+  // expected-error@+3 {{'@IBOutlet' property has non-optional type 'OX'}}
   // expected-note @+2 {{add '?' to form the optional type 'OX?'}}
   // expected-note @+1 {{add '!' to form an implicitly unwrapped optional}}
   @IBOutlet var ox: OX
@@ -165,7 +165,7 @@ class NonObjC {}
 // https://github.com/apple/swift/issues/52295
 
 @objc class NonOptionalWeak {
-  // expected-error@+3 {{@IBOutlet property has non-optional type 'OX'}}
+  // expected-error@+3 {{'@IBOutlet' property has non-optional type 'OX'}}
   // expected-note @+2 {{add '?' to form the optional type 'OX?'}}
   // expected-note @+1 {{add '!' to form an implicitly unwrapped optional}}
   @IBOutlet weak var something: OX
diff --git a/test/attr/attr_ibsegueaction.swift b/test/attr/attr_ibsegueaction.swift
index a8a4432383367..82460e599c4c0 100644
--- a/test/attr/attr_ibsegueaction.swift
+++ b/test/attr/attr_ibsegueaction.swift
@@ -34,7 +34,7 @@ class IBActionWrapperTy {
   func process(x: AnyObject, _: AnyObject, _: AnyObject) {}  // expected-error {{methods declared @IBSegueAction must return a value}}
 
   @IBSegueAction
-  func process(_: AnyObject, _: AnyObject, _: AnyObject) -> Int? {fatalError()}  // expected-error {{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
+  func process(_: AnyObject, _: AnyObject, _: AnyObject) -> Int? {fatalError()}  // expected-error {{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
 
   // @IBSegueAction does /not/ semantically imply @objc.
   @IBSegueAction // expected-note {{attribute already specified here}}
@@ -135,39 +135,39 @@ protocol CP2 : class { }
   @IBSegueAction func action6a(_: Any!, _: Any!, _: Any!) -> Any! {fatalError()}
 
   // Protocol types
-  @IBSegueAction func action7a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1 {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
-  @IBSegueAction func action7b(_: P1, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
-  @IBSegueAction func action7c(_: AnyObject, _: P1, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
-  @IBSegueAction func action7d(_: AnyObject, _: AnyObject, _: P1) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
+  @IBSegueAction func action7a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1 {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
+  @IBSegueAction func action7b(_: P1, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
+  @IBSegueAction func action7c(_: AnyObject, _: P1, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
+  @IBSegueAction func action7d(_: AnyObject, _: AnyObject, _: P1) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'P1' cannot be represented in Objective-C}}
 
-  @IBSegueAction func action8a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1 {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
-  @IBSegueAction func action7b(_: CP1, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
-  @IBSegueAction func action7c(_: AnyObject, _: CP1, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
-  @IBSegueAction func action7d(_: AnyObject, _: AnyObject, _: CP1) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
+  @IBSegueAction func action8a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1 {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
+  @IBSegueAction func action7b(_: CP1, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
+  @IBSegueAction func action7c(_: AnyObject, _: CP1, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
+  @IBSegueAction func action7d(_: AnyObject, _: AnyObject, _: CP1) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}} expected-note{{protocol-constrained type containing protocol 'CP1' cannot be represented in Objective-C}}
 
   @IBSegueAction func action9(_: OP1, _: OP1, _: OP1) -> OP1 {fatalError()}
 
-  @IBSegueAction func action10a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1? {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action10b(_: P1?, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action10c(_: AnyObject, _: P1?, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action10d(_: AnyObject, _: AnyObject, _: P1?) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action10a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1? {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action10b(_: P1?, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action10c(_: AnyObject, _: P1?, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action10d(_: AnyObject, _: AnyObject, _: P1?) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
-  @IBSegueAction func action11a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1? {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action11b(_: CP1?, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action11c(_: AnyObject, _: CP1?, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action11d(_: AnyObject, _: AnyObject, _: CP1?) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action11a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1? {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action11b(_: CP1?, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action11c(_: AnyObject, _: CP1?, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action11d(_: AnyObject, _: AnyObject, _: CP1?) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
   @IBSegueAction func action12(_: OP1?, _: OP1?, _: OP1?) -> OP1? {fatalError()}
 
-  @IBSegueAction func action13a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1! {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action13b(_: P1!, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action13c(_: AnyObject, _: P1!, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action13d(_: AnyObject, _: AnyObject, _: P1!) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action13a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1! {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action13b(_: P1!, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action13c(_: AnyObject, _: P1!, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action13d(_: AnyObject, _: AnyObject, _: P1!) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
-  @IBSegueAction func action14a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1! {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action14b(_: CP1!, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action14c(_: AnyObject, _: CP1!, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action14d(_: AnyObject, _: AnyObject, _: CP1!) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action14a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1! {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action14b(_: CP1!, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action14c(_: AnyObject, _: CP1!, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action14d(_: AnyObject, _: AnyObject, _: CP1!) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
   @IBSegueAction func action15(_: OP1!, _: OP1!, _: OP1!) -> OP1! {fatalError()}
 
@@ -182,52 +182,52 @@ protocol CP2 : class { }
   @IBSegueAction func action20(_: AnyClass!, _: AnyClass!, _: AnyClass!) -> AnyClass! {fatalError()}
 
   // Protocol types
-  @IBSegueAction func action21a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1.Type {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action21b(_: P1.Type, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action21c(_: AnyObject, _: P1.Type, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action21d(_: AnyObject, _: AnyObject, _: P1.Type) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action21a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1.Type {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action21b(_: P1.Type, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action21c(_: AnyObject, _: P1.Type, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action21d(_: AnyObject, _: AnyObject, _: P1.Type) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
-  @IBSegueAction func action22a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1.Type {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action22b(_: CP1.Type, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action22c(_: AnyObject, _: CP1.Type, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action22d(_: AnyObject, _: AnyObject, _: CP1.Type) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action22a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1.Type {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action22b(_: CP1.Type, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action22c(_: AnyObject, _: CP1.Type, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action22d(_: AnyObject, _: AnyObject, _: CP1.Type) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
   @IBSegueAction func action23(_: OP1.Type, _: OP1.Type, _: OP1.Type) -> OP1.Type {fatalError()}
 
-  @IBSegueAction func action24a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1.Type? {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action24b(_: P1.Type?, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action24c(_: AnyObject, _: P1.Type?, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action24d(_: AnyObject, _: AnyObject, _: P1.Type?) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action24a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1.Type? {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action24b(_: P1.Type?, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action24c(_: AnyObject, _: P1.Type?, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action24d(_: AnyObject, _: AnyObject, _: P1.Type?) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
-  @IBSegueAction func action25a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1.Type? {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action25b(_: CP1.Type?, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action25c(_: AnyObject, _: CP1.Type?, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action25d(_: AnyObject, _: AnyObject, _: CP1.Type?) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action25a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1.Type? {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action25b(_: CP1.Type?, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action25c(_: AnyObject, _: CP1.Type?, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action25d(_: AnyObject, _: AnyObject, _: CP1.Type?) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
   @IBSegueAction func action26(_: OP1.Type?, _: OP1.Type?, _: OP1.Type?) -> OP1.Type? {fatalError()}
 
-  @IBSegueAction func action27a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1.Type! {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action27b(_: P1.Type!, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action27c(_: AnyObject, _: P1.Type!, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action27d(_: AnyObject, _: AnyObject, _: P1.Type!) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action27a(_: AnyObject, _: AnyObject, _: AnyObject) -> P1.Type! {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action27b(_: P1.Type!, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action27c(_: AnyObject, _: P1.Type!, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action27d(_: AnyObject, _: AnyObject, _: P1.Type!) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
-  @IBSegueAction func action28a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1.Type! {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}}
-  @IBSegueAction func action28b(_: CP1.Type!, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}}
-  @IBSegueAction func action28c(_: AnyObject, _: CP1.Type!, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}}
-  @IBSegueAction func action28d(_: AnyObject, _: AnyObject, _: CP1.Type!) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}}
+  @IBSegueAction func action28a(_: AnyObject, _: AnyObject, _: AnyObject) -> CP1.Type! {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}}
+  @IBSegueAction func action28b(_: CP1.Type!, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}}
+  @IBSegueAction func action28c(_: AnyObject, _: CP1.Type!, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}}
+  @IBSegueAction func action28d(_: AnyObject, _: AnyObject, _: CP1.Type!) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}}
 
   @IBSegueAction func action29(_: OP1.Type!, _: OP1.Type!, _: OP1.Type!) -> OP1.Type! {fatalError()}
 
   // Other bad cases
-  @IBSegueAction func action30a(_: AnyObject, _: AnyObject, _: AnyObject) -> S {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
-  @IBSegueAction func action30b(_: S, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
-  @IBSegueAction func action30c(_: AnyObject, _: S, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
-  @IBSegueAction func action30d(_: AnyObject, _: AnyObject, _: S) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
-
-  @IBSegueAction func action31a(_: AnyObject, _: AnyObject, _: AnyObject) -> E {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because its result type cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
-  @IBSegueAction func action31b(_: E, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 1 cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
-  @IBSegueAction func action31c(_: AnyObject, _: E, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 2 cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
-  @IBSegueAction func action31d(_: AnyObject, _: AnyObject, _: E) -> AnyObject {fatalError()} // expected-error{{method cannot be marked @IBSegueAction because the type of the parameter 3 cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
+  @IBSegueAction func action30a(_: AnyObject, _: AnyObject, _: AnyObject) -> S {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
+  @IBSegueAction func action30b(_: S, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
+  @IBSegueAction func action30c(_: AnyObject, _: S, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
+  @IBSegueAction func action30d(_: AnyObject, _: AnyObject, _: S) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}} expected-note{{Swift structs cannot be represented in Objective-C}}
+
+  @IBSegueAction func action31a(_: AnyObject, _: AnyObject, _: AnyObject) -> E {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because its result type cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
+  @IBSegueAction func action31b(_: E, _: AnyObject, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 1 cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
+  @IBSegueAction func action31c(_: AnyObject, _: E, _: AnyObject) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 2 cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
+  @IBSegueAction func action31d(_: AnyObject, _: AnyObject, _: E) -> AnyObject {fatalError()} // expected-error{{method cannot be marked '@IBSegueAction' because the type of the parameter 3 cannot be represented in Objective-C}} expected-note{{non-'@objc' enums cannot be represented in Objective-C}}
 
   // Supported arities
   @IBSegueAction func actionWith0() -> X {fatalError()} // expected-error{{@IBSegueAction methods must have 1 to 3 arguments}}
diff --git a/test/attr/attr_implements_bad_types.swift b/test/attr/attr_implements_bad_types.swift
index 5aef48979c3f5..8bcc341280a83 100644
--- a/test/attr/attr_implements_bad_types.swift
+++ b/test/attr/attr_implements_bad_types.swift
@@ -14,12 +14,16 @@ struct S0 : NeedsF0 {  // expected-error {{type 'S0' does not conform to protoco
   func gg0() {
   }
 
-  @_implements(Int, zz) // expected-error {{non-protocol type in @_implements attribute}}
+  @_implements(Int, zz) // expected-error {{non-protocol type in '@_implements'}}
   static func gg1(x:S0, y:S0) -> Bool {
   }
 
   @_implements(Equatable, ==(_:_:)) // expected-error {{containing type 'S0' does not conform to protocol 'Equatable'}}
   static func gg2(x:S0, y:S0) -> Bool {
   }
+
+  @_implements(NonexistentType, ff3()) // expected-error {{cannot find type 'NonexistentType' in scope}}
+  func gg3() {
+  }
 }
 
diff --git a/test/attr/attr_inheritActorContext.swift b/test/attr/attr_inheritActorContext.swift
new file mode 100644
index 0000000000000..7d490878a12c5
--- /dev/null
+++ b/test/attr/attr_inheritActorContext.swift
@@ -0,0 +1,38 @@
+// RUN: %target-typecheck-verify-swift
+
+func test1(@_inheritActorContext _: @Sendable () async -> Void) {} // Ok
+func test2(@_inheritActorContext(always) _: sending () async -> Void) {} // Ok
+
+func test3(@_inheritActorContext _: () async -> Void) {}
+// expected-warning@-1 {{@_inheritActorContext only applies to 'sending' parameters or parameters with '@Sendable' function types}}
+func test3(@_inheritActorContext _: @Sendable () -> Void) {}
+// expected-warning@-1 {{@_inheritActorContext only applies to '@isolated(any)' parameters or parameters with asynchronous function types}}
+
+func test4(@_inheritActorContext _: Int) {}
+// expected-error@-1 {{@_inheritActorContext only applies to parameters with function types (got: 'Int')}}
+
+func test5(@_inheritActorContext _: sending Optional<() async -> Int>) {} // Ok
+func test6(@_inheritActorContext _: (Optional<@Sendable () async -> Int>)?) {} // Ok
+func test6(@_inheritActorContext _: (Optional<@Sendable @isolated(any) () -> Int>)?) {} // Ok
+
+func test7(@_inheritActorContext _: Int?) {} // Ok
+// expected-error@-1 {{@_inheritActorContext only applies to parameters with function types (got: 'Int?')}}
+
+struct S {
+  init(@_inheritActorContext(always) _: @escaping @Sendable () async -> Void) {} // Ok
+
+  var test: @_inheritActorContext () async -> Void { // expected-error {{attribute can only be applied to declarations, not types}}
+    { }
+  }
+
+  subscript(@_inheritActorContext _: @Sendable () async -> Void) -> Bool { false } // Ok
+  subscript(@_inheritActorContext(always) _: @Sendable (Int) async -> Void) -> Bool { false } // Ok
+
+  subscript(@_inheritActorContext _: sending (String) async -> Void) -> Bool { false }
+  subscript(x: Int, @_inheritActorContext(always) _: @Sendable (Int, Int) async -> Void) -> Bool { false }
+
+  func testClosure() {
+    _ = { @_inheritActorContext in // expected-error {{attribute @_inheritActorContext is not supported on a closure}}
+    }
+  }
+}
diff --git a/test/attr/attr_inlinable_available.swift b/test/attr/attr_inlinable_available.swift
deleted file mode 100644
index 1f948801dc06f..0000000000000
--- a/test/attr/attr_inlinable_available.swift
+++ /dev/null
@@ -1,1859 +0,0 @@
-// A module with library evolution enabled has two different "minimum versions".
-// One, the minimum deployment target, is the lowest version that non-ABI
-// declarations and bodies of non-inlinable functions will ever see. The other,
-// the minimum inlining target, is the lowest version that ABI declarations and
-// inlinable bodies will ever see.
-//
-// Test that we use the right version floor in the right places.
-
-// REQUIRES: OS=macosx
-
-// Primary execution of this test. Uses the default minimum inlining version,
-// which is the version when Swift was introduced.
-// RUN: %target-typecheck-verify-swift -swift-version 5 -enable-library-evolution -parse-as-library -module-name Test -target %target-next-stable-abi-triple -target-min-inlining-version min
-
-
-// Check that `-library-level api` implies `-target-min-inlining-version min`
-// RUN: %target-typecheck-verify-swift -swift-version 5 -enable-library-evolution -parse-as-library -module-name Test -target %target-next-stable-abi-triple -library-level api -require-explicit-availability=ignore
-
-
-// Check that these rules are only applied when requested and that at least some
-// diagnostics are not present without it.
-// RUN: not %target-typecheck-verify-swift -swift-version 5 -enable-library-evolution -parse-as-library -module-name Test -target %target-next-stable-abi-triple 2>&1 | %FileCheck --check-prefix NON_MIN %s
-
-
-// Check that -target-min-inlining-version overrides -library-level, allowing
-// library owners to disable this behavior for API libraries if needed.
-// RUN: not %target-typecheck-verify-swift -swift-version 5 -enable-library-evolution -parse-as-library -module-name Test -target %target-next-stable-abi-triple -target-min-inlining-version target -library-level api -require-explicit-availability=ignore 2>&1 | %FileCheck --check-prefix NON_MIN %s
-
-
-// Check that we respect -target-min-inlining-version by cranking it up high
-// enough to suppress any possible errors.
-// RUN: %target-swift-frontend -typecheck -disable-objc-attr-requires-foundation-module %s -swift-version 5 -enable-library-evolution  -parse-as-library -module-name Test -target %target-next-stable-abi-triple -target-min-inlining-version 42.0
-
-
-// NON_MIN: error: expected error not produced
-// NON_MIN: {'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}
-
-
-// MARK: - Struct definitions
-
-/// Declaration with no availability annotation. Should be inferred as minimum
-/// inlining target.
-public struct NoAvailable {
-  @usableFromInline internal init() {}
-  init<T>(_ t: T) {}
-}
-
-@available(macOS 10.9, *)
-public struct BeforeInliningTarget {
-  @usableFromInline internal init() {}
-  init<T>(_ t: T) {}
-}
-
-@available(macOS 10.10, *)
-public struct AtInliningTarget {
-  @usableFromInline internal init() {}
-  init<T>(_ t: T) {}
-}
-
-@available(macOS 10.14.5, *)
-public struct BetweenTargets { // expected-note {{enclosing scope requires availability of macOS 10.14.5 or newer}}
-  @usableFromInline internal init() {}
-  init<T>(_ t: T) {}
-}
-
-@available(macOS 10.15, *)
-public struct AtDeploymentTarget {
-  @usableFromInline internal init() {}
-  init<T>(_ t: T) {}
-}
-
-@available(macOS 11, *)
-public struct AfterDeploymentTarget {
-  @usableFromInline internal init() {}
-  init<T>(_ t: T) {}
-}
-
-@available(macOS, unavailable)
-public struct Unavailable {
-  @usableFromInline internal init() {}
-  init<T>(_ t: T) {}
-}
-
-// MARK: - Protocol definitions
-
-public protocol NoAvailableProto {}
-
-@available(macOS 10.9, *)
-public protocol BeforeInliningTargetProto {}
-
-@available(macOS 10.10, *)
-public protocol AtInliningTargetProto {}
-
-@available(macOS 10.14.5, *)
-public protocol BetweenTargetsProto {}
-
-@available(macOS 10.15, *)
-public protocol AtDeploymentTargetProto {}
-
-@available(macOS 11, *)
-public protocol AfterDeploymentTargetProto {}
-
-@available(macOS, unavailable)
-public protocol UnavailableProto {}
-
-// MARK: - Class definitions
-
-public class NoAvailableClass {}
-
-@available(macOS 10.9, *)
-public class BeforeInliningTargetClass {}
-
-@available(macOS 10.10, *)
-public class AtInliningTargetClass {}
-
-@available(macOS 10.14.5, *)
-public class BetweenTargetsClass {}
-
-@available(macOS 10.15, *)
-public class AtDeploymentTargetClass {}
-
-@available(macOS 11, *)
-public class AfterDeploymentTargetClass {}
-
-@available(macOS, unavailable)
-public class UnavailableClass {}
-
-
-// MARK: - Internal functions
-
-//
-// Both the signature and the body of internal functions should be typechecked
-// using the minimum deployment target.
-//
-
-internal func internalFn( // expected-note 3 {{add @available attribute to enclosing global function}}
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget,
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-// MARK: - Resilient functions
-
-//
-// The body of a resilient function is typechecked using the minimum deployment
-// but the function's signature should be checked with the inlining target.
-//
-
-public func deployedUseNoAvailable( // expected-note 5 {{add @available attribute}}
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 10.9, *)
-public func deployedUseBeforeInliningTarget(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 10.10, *)
-public func deployedUseAtInliningTarget(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 10.14.5, *)
-public func deployedUseBetweenTargets(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 10.15, *)
-public func deployedUseAtDeploymentTarget(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget,
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 11, *)
-public func deployedUseAfterDeploymentTarget(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget,
-  _: AfterDeploymentTarget
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget()
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget()
-}
-
-@available(macOS, unavailable)
-public func alwaysUnavailable(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget,
-  _: AfterDeploymentTarget,
-  _: Unavailable
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  _ = Unavailable()
-  
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@_spi(Private)
-public func spiDeployedUseNoAvailable( // expected-note 3 {{add @available attribute}}
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget,
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-// MARK: - @inlinable functions
-
-//
-// Both the bodies and signatures of inlinable functions need to be typechecked
-// using the minimum inlining target.
-//
-
-@inlinable public func inlinedUseNoAvailable( // expected-note 13 {{add @available attribute}}
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 10.14.5, *) {
-    _ = BetweenTargets()
-  }
-  if #available(macOS 10.15, *) {
-    _ = AtDeploymentTarget()
-  }
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-
-  // Repeat everything with pattern binding decls instead of discard expressions.
-  defer {
-    let _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-    let _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  let _ = NoAvailable()
-  let _ = BeforeInliningTarget()
-  let _ = AtInliningTarget()
-  let _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  let _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  let _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 10.14.5, *) {
-    let _ = BetweenTargets()
-  }
-  if #available(macOS 10.15, *) {
-    let _ = AtDeploymentTarget()
-  }
-  if #available(macOS 11, *) {
-    let _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 10.9, *)
-@inlinable public func inlinedUseBeforeInliningTarget(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 10.14.5, *) {
-    _ = BetweenTargets()
-  }
-  if #available(macOS 10.15, *) {
-    _ = AtDeploymentTarget()
-  }
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 10.10, *)
-@inlinable public func inlinedUseAtInliningTarget(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 10.14.5, *) {
-    _ = BetweenTargets()
-  }
-  if #available(macOS 10.15, *) {
-    _ = AtDeploymentTarget()
-  }
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 10.14.5, *)
-@inlinable public func inlinedUseBetweenTargets(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 10.15, *) {
-    _ = AtDeploymentTarget()
-  }
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 10.15, *)
-@inlinable public func inlinedUseAtDeploymentTarget(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget,
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@available(macOS 11, *)
-@inlinable public func inlinedUseAfterDeploymentTarget(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget,
-  _: AfterDeploymentTarget
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget()
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget()
-}
-
-@available(macOS, unavailable)
-@inlinable public func inlinedAlwaysUnavailable(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget,
-  _: AfterDeploymentTarget,
-  _: Unavailable
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  _ = Unavailable()
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-@_spi(Private)
-@inlinable public func spiInlinedUseNoAvailable( // expected-note 3 {{add @available attribute}}
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets,
-  _: AtDeploymentTarget,
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-// MARK: - @inlinable global property accessors
-
-@inlinable public var inlinedNoAvailableGlobal: Any { // expected-note 3 {{add @available attribute to enclosing var}}
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
-  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-
-  return ()
-}
-
-@inlinable public var inlinedNoAvailableGlobalExplicitGetter: Any { // expected-note 3 {{add @available attribute to enclosing var}}
-  get {
-    _ = NoAvailable()
-    _ = BeforeInliningTarget()
-    _ = AtInliningTarget()
-    _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
-    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-    if #available(macOS 11, *) {
-      _ = AfterDeploymentTarget()
-    }
-
-    return ()
-  }
-}
-
-@available(macOS 10.15, *)
-@inlinable public var inlinedAtDeploymentTargetGlobal: Any {
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-
-  return ()
-}
-
-@inlinable public var inlinedGlobalGetterAtDeploymentTarget: Any { // expected-note {{add @available attribute to enclosing var}}
-  @available(macOS 10.15, *)
-  get {
-    _ = NoAvailable()
-    _ = BeforeInliningTarget()
-    _ = AtInliningTarget()
-    _ = BetweenTargets()
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-    if #available(macOS 11, *) {
-      _ = AfterDeploymentTarget()
-    }
-
-    return ()
-  }
-}
-
-@_spi(Private)
-@inlinable public var inlinedNoAvailableSPIGlobal: Any { // expected-note {{add @available attribute to enclosing var}}
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-
-  return ()
-}
-
-@inlinable public var inlinedNoAvailableGlobalSPISetter: Any { // expected-note {{add @available attribute to enclosing var}}
-  get {
-    fatalError()
-  }
-  @_spi(Private)
-  set {
-    _ = NoAvailable()
-    _ = BeforeInliningTarget()
-    _ = AtInliningTarget()
-    _ = BetweenTargets()
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-    if #available(macOS 11, *) {
-      _ = AfterDeploymentTarget()
-    }
-  }
-}
-
-@available(macOS, unavailable)
-@inlinable public var inlinedUnavailableGlobal: Any {
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets()
-  _ = AtDeploymentTarget()
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-
-  return ()
-}
-
-@inlinable public var inlinedNoAvailableGlobalUnavailableSetter: Any { // expected-note {{add @available attribute to enclosing var}}
-  get {
-    fatalError()
-  }
-  @available(macOS, unavailable)
-  set {
-    _ = NoAvailable()
-    _ = BeforeInliningTarget()
-    _ = AtInliningTarget()
-    _ = BetweenTargets()
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-    if #available(macOS 11, *) {
-      _ = AfterDeploymentTarget()
-    }
-  }
-}
-
-// MARK: - @_alwaysEmitIntoClient functions
-
-// @_alwaysEmitIntoClient acts like @inlinable.
-
-@_alwaysEmitIntoClient public func aEICUseNoAvailable( // expected-note 8 {{add @available attribute}}
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 10.14.5, *) {
-    _ = BetweenTargets()
-  }
-  if #available(macOS 10.15, *) {
-    _ = AtDeploymentTarget()
-  }
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-
-// MARK: - @backDeployed functions
-
-// @backDeployed acts like @inlinable.
-
-@available(macOS 10.10, *)
-@backDeployed(before: macOS 999.0)
-public func backDeployedToInliningTarget(
-  _: NoAvailable,
-  _: BeforeInliningTarget,
-  _: AtInliningTarget,
-  _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {
-  defer {
-    _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-  }
-  _ = NoAvailable()
-  _ = BeforeInliningTarget()
-  _ = AtInliningTarget()
-  _ = BetweenTargets() // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-  if #available(macOS 10.14.5, *) {
-    _ = BetweenTargets()
-  }
-  if #available(macOS 10.15, *) {
-    _ = AtDeploymentTarget()
-  }
-  if #available(macOS 11, *) {
-    _ = AfterDeploymentTarget()
-  }
-}
-
-
-// MARK: - Default arguments
-
-// Default arguments act like @inlinable when in a public function.
-
-public func defaultArgsUseNoAvailable( // expected-note 3 {{add @available attribute}}
-  _: Any = NoAvailable.self,
-  _: Any = BeforeInliningTarget.self,
-  _: Any = AtInliningTarget.self,
-  _: Any = BetweenTargets.self, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  _: Any = AtDeploymentTarget.self, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  _: Any = AfterDeploymentTarget.self // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {}
-
-func defaultArgsUseInternal( // expected-note {{add @available attribute}}
-  _: Any = NoAvailable.self,
-  _: Any = BeforeInliningTarget.self,
-  _: Any = AtInliningTarget.self,
-  _: Any = BetweenTargets.self,
-  _: Any = AtDeploymentTarget.self,
-  _: Any = AfterDeploymentTarget.self // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {}
-
-@available(macOS, unavailable)
-public func defaultArgsUseUnavailable(
-  _: Any = NoAvailable.self,
-  _: Any = BeforeInliningTarget.self,
-  _: Any = AtInliningTarget.self,
-  _: Any = BetweenTargets.self,
-  _: Any = AtDeploymentTarget.self,
-  _: Any = AfterDeploymentTarget.self, // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  _: Any = Unavailable.self
-) {}
-
-@_spi(Private)
-public func spiDefaultArgsUseNoAvailable( // expected-note 1 {{add @available attribute}}
-  _: Any = NoAvailable.self,
-  _: Any = BeforeInliningTarget.self,
-  _: Any = AtInliningTarget.self,
-  _: Any = BetweenTargets.self,
-  _: Any = AtDeploymentTarget.self,
-  _: Any = AfterDeploymentTarget.self // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-) {}
-
-// Verify that complex default argument expressions are checked appropriately.
-public func defaultArgsClosureExprNoAvailable( // expected-note 3 {{add @available attribute}}
-  _: Int = {
-    _ = NoAvailable.self
-    _ = BeforeInliningTarget.self
-    _ = AtInliningTarget.self
-    _ = BetweenTargets.self // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
-    _ = AtDeploymentTarget.self // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available' version check}}
-    _ = AfterDeploymentTarget.self // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available' version check}}
-    if #available(macOS 10.14.5, *) {
-      _ = BetweenTargets.self
-    }
-    if #available(macOS 10.15, *) {
-      _ = AtDeploymentTarget.self
-    }
-    if #available(macOS 11, *) {
-      _ = AfterDeploymentTarget.self
-    }
-    return 42
-  }()
-) {}
-
-func defaultArgsClosureExprInternal( // expected-note {{add @available attribute}}
-  _: Int = {
-    _ = NoAvailable.self
-    _ = BeforeInliningTarget.self
-    _ = AtInliningTarget.self
-    _ = BetweenTargets.self
-    _ = AtDeploymentTarget.self
-    _ = AfterDeploymentTarget.self // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available' version check}}
-    if #available(macOS 11, *) {
-      _ = AfterDeploymentTarget.self
-    }
-    return 42
-  }()
-) {}
-
-
-// MARK: - Properties
-
-@propertyWrapper
-public struct PropertyWrapper<T> {
-  public var wrappedValue: T
-
-  public init(wrappedValue value: T) { self.wrappedValue = value }
-  public init(_ value: T) { self.wrappedValue = value }
-}
-
-public struct PublicStruct { // expected-note 21 {{add @available attribute}}
-  // Public property declarations are exposed.
-  public var aPublic: NoAvailable,
-             bPublic: BeforeInliningTarget,
-             cPublic: AtInliningTarget,
-             dPublic: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-             ePublic: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-             fPublic: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @available(macOS 10.14.5, *)
-  public var aPublicAvailBetween: NoAvailable,
-             bPublicAvailBetween: BeforeInliningTarget,
-             cPublicAvailBetween: AtInliningTarget,
-             dPublicAvailBetween: BetweenTargets,
-             ePublicAvailBetween: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-             fPublicAvailBetween: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @_spi(Private)
-  public var aSPI: NoAvailable,
-             bSPI: BeforeInliningTarget,
-             cSPI: AtInliningTarget,
-             dSPI: BetweenTargets,
-             eSPI: AtDeploymentTarget,
-             fSPI: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @available(macOS, unavailable)
-  public var aUnavailable: NoAvailable {
-    NoAvailable()
-  }
-
-  @available(macOS, unavailable)
-  public var bUnavailable: BeforeInliningTarget {
-    BeforeInliningTarget()
-  }
-
-  @available(macOS, unavailable)
-  public var cUnavailable: AtInliningTarget {
-    AtInliningTarget()
-  }
-
-  @available(macOS, unavailable)
-  public var dUnavailable: BetweenTargets {
-    BetweenTargets()
-  }
-
-  @available(macOS, unavailable)
-  public var eUnavailable: AtDeploymentTarget {
-    AtDeploymentTarget()
-  }
-
-  @available(macOS, unavailable)
-  public var fUnavailable: AfterDeploymentTarget {
-    AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available' version check}}
-  }
-
-  // The inferred types of public properties are exposed.
-  public var aPublicInferred = NoAvailable(),
-             bPublicInferred = BeforeInliningTarget(),
-             cPublicInferred = AtInliningTarget(),
-             dPublicInferred = BetweenTargets(), // FIXME: Inferred type should be diagnosed
-             ePublicInferred = AtDeploymentTarget(), // FIXME: Inferred type should be diagnosed
-             fPublicInferred = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @available(macOS 10.14.5, *)
-  public var aPublicInferredAvailBetween = NoAvailable(),
-             bPublicInferredAvailBetween = BeforeInliningTarget(),
-             cPublicInferredAvailBetween = AtInliningTarget(),
-             dPublicInferredAvailBetween = BetweenTargets(),
-             ePublicInferredAvailBetween = AtDeploymentTarget(), // FIXME: Inferred type should be diagnosed
-             fPublicInferredAvailBetween = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  
-  // Property initializers are not exposed.
-  public var aPublicInit: Any = NoAvailable(),
-             bPublicInit: Any = BeforeInliningTarget(),
-             cPublicInit: Any = AtInliningTarget(),
-             dPublicInit: Any = BetweenTargets(),
-             ePublicInit: Any = AtDeploymentTarget(),
-             fPublicInit: Any = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @available(macOS 10.14.5, *)
-  public var  aPublicInitAvailBetween: Any = {
-                if #available(macOS 11, *) {
-                  return NoAvailable(AfterDeploymentTarget())
-                } else {
-                  return NoAvailable(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-                }
-              }(),
-              bPublicInitAvailBetween: Any = {
-                if #available(macOS 11, *) {
-                  return BeforeInliningTarget(AfterDeploymentTarget())
-                } else {
-                  return BeforeInliningTarget(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-                }
-              }(),
-              cPublicInitAvailBetween: Any = {
-                if #available(macOS 11, *) {
-                  return AtInliningTarget(AfterDeploymentTarget())
-                } else {
-                  return AtInliningTarget(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-                }
-              }(),
-              dPublicInitAvailBetween: Any = {
-                if #available(macOS 11, *) {
-                  return BetweenTargets(AfterDeploymentTarget())
-                } else {
-                  return BetweenTargets(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-                }
-              }(),
-              ePublicInitAvailBetween: Any = {
-                if #available(macOS 11, *) {
-                  return AtDeploymentTarget(AfterDeploymentTarget())
-                } else {
-                  return AtDeploymentTarget(AfterDeploymentTarget()) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-                }
-              }(),
-              fPublicInitAvailBetween: Any = {
-                if #available(macOS 11, *) {
-                  return AfterDeploymentTarget()
-                } else {
-                  return AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-                }
-              }()
-
-  // Internal declarations are not exposed.
-  var aInternal: NoAvailable = .init(),
-      bInternal: BeforeInliningTarget = .init(),
-      cInternal: AtInliningTarget = .init(),
-      dInternal: BetweenTargets = .init(),
-      eInternal: AtDeploymentTarget = .init(),
-      fInternal: AfterDeploymentTarget = .init() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @available(macOS 10.14.5, *)
-  public internal(set) var internalSetter: Void {
-    @inlinable get {
-      // Public inlinable getter acts like @inlinable
-      _ = NoAvailable()
-      _ = BeforeInliningTarget()
-      _ = AtInliningTarget()
-      _ = BetweenTargets()
-      _ = AtDeploymentTarget() // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add 'if #available'}}
-      _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-      if #available(macOS 10.15, *) {
-        _ = AtDeploymentTarget()
-      }
-      if #available(macOS 11, *) {
-        _ = AfterDeploymentTarget()
-      }
-    }
-    set {
-      // Private setter acts like non-inlinable
-      _ = NoAvailable()
-      _ = BeforeInliningTarget()
-      _ = AtInliningTarget()
-      _ = BetweenTargets()
-      _ = AtDeploymentTarget()
-      _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-
-      if #available(macOS 11, *) {
-        _ = AfterDeploymentTarget()
-      }
-    }
-  }
-  
-  public var block: () -> () = {
-    // The body of a block assigned to a public property acts like non-@inlinable
-    _ = NoAvailable()
-    _ = BeforeInliningTarget()
-    _ = AtInliningTarget()
-    _ = BetweenTargets()
-    _ = AtDeploymentTarget()
-    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available'}}
-    
-    if #available(macOS 11, *) {
-      _ = AfterDeploymentTarget()
-    }
-  }
-}
-
-public struct PublicStructWithWrappers { // expected-note 4 {{add @available attribute}}
-  // The property type is inferred from the initializer expression. The
-  // expressions themselves will not be exposed.
-  @PropertyWrapper public var aExplicitInit = NoAvailable()
-  @PropertyWrapper public var bExplicitInit = BeforeInliningTarget()
-  @PropertyWrapper public var cExplicitInit = AtInliningTarget()
-  @PropertyWrapper public var dExplicitInit = BetweenTargets() // FIXME: Inferred type should be diagnosed
-  @PropertyWrapper public var eExplicitInit = AtDeploymentTarget() // FIXME: Inferred type should be diagnosed
-  @PropertyWrapper public var fExplicitInit = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  
-  // The property type is inferred from the initializer expression. The
-  // expressions themselves will not be exposed.
-  @PropertyWrapper(NoAvailable()) public var aExplicitInitAlt
-  @PropertyWrapper(BeforeInliningTarget()) public var bExplicitInitAlt
-  @PropertyWrapper(AtInliningTarget()) public var cExplicitInitAlt
-  @PropertyWrapper(BetweenTargets()) public var dExplicitInitAlt  // FIXME: Inferred type should be diagnosed
-  @PropertyWrapper(AtDeploymentTarget()) public var ePExplicitInitAlt  // FIXME: Inferred type should be diagnosed
-  @PropertyWrapper(AfterDeploymentTarget()) public var fExplicitInitAlt // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  // The property type is explicitly `Any` and the initializer expressions are
-  // not exposed.
-  @PropertyWrapper public var aAny: Any = NoAvailable()
-  @PropertyWrapper public var bAny: Any = BeforeInliningTarget()
-  @PropertyWrapper public var cAny: Any = AtInliningTarget()
-  @PropertyWrapper public var dAny: Any = BetweenTargets()
-  @PropertyWrapper public var eAny: Any = AtDeploymentTarget()
-  @PropertyWrapper public var fAny: Any = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  // The property type is explicitly `Any` and the initializer expressions are
-  // not exposed.
-  @PropertyWrapper(NoAvailable()) public var aAnyAlt: Any
-  @PropertyWrapper(BeforeInliningTarget()) public var bAnyAlt: Any
-  @PropertyWrapper(AtInliningTarget()) public var cAnyAlt: Any
-  @PropertyWrapper(BetweenTargets()) public var dAnyAlt: Any
-  @PropertyWrapper(AtDeploymentTarget()) public var eAnyAlt: Any
-  @PropertyWrapper(AfterDeploymentTarget()) public var fAnyAlt: Any // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-}
-
-@frozen public struct FrozenPublicStruct { // expected-note 9 {{add @available attribute}}
-  // Public declarations are exposed.
-  public var aPublic: NoAvailable,
-             bPublic: BeforeInliningTarget,
-             cPublic: AtInliningTarget,
-             dPublic: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-             ePublic: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-             fPublic: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  // Property initializers are exposed in frozen structs.
-  public var aPublicInit: Any = NoAvailable(),
-             bPublicInit: Any = BeforeInliningTarget(),
-             cPublicInit: Any = AtInliningTarget(),
-             dPublicInit: Any = BetweenTargets(), // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-             ePublicInit: Any = AtDeploymentTarget(), // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-             fPublicInit: Any = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  // Internal declarations are also exposed in frozen structs.
-  var aInternal: NoAvailable = .init(),
-      bInternal: BeforeInliningTarget = .init(),
-      cInternal: AtInliningTarget = .init(),
-      dInternal: BetweenTargets = .init(), // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-      eInternal: AtDeploymentTarget = .init(), // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-      fInternal: AfterDeploymentTarget = .init() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-}
-
-@available(macOS, unavailable)
-public struct UnavailablePublicStruct {
-  public var aPublic: NoAvailable,
-             bPublic: BeforeInliningTarget,
-             cPublic: AtInliningTarget,
-             dPublic: BetweenTargets,
-             ePublic: AtDeploymentTarget,
-             fPublic: AfterDeploymentTarget,
-             gPublic: Unavailable
-
-  public var aPublicInit: Any = NoAvailable(),
-             bPublicInit: Any = BeforeInliningTarget(),
-             cPublicInit: Any = AtInliningTarget(),
-             dPublicInit: Any = BetweenTargets(),
-             ePublicInit: Any = AtDeploymentTarget(),
-             fPublicInit: Any = AfterDeploymentTarget(), // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-             gPublicInit: Any = Unavailable()
-
-  var aInternal: NoAvailable = .init(),
-      bInternal: BeforeInliningTarget = .init(),
-      cInternal: AtInliningTarget = .init(),
-      dInternal: BetweenTargets = .init(),
-      eInternal: AtDeploymentTarget = .init(),
-      fInternal: AfterDeploymentTarget = .init(),
-      gInternal: Unavailable = .init()
-}
-
-@_spi(Private)
-public struct SPIStruct { // expected-note 3 {{add @available attribute}}
-  public var aPublic: NoAvailable,
-             bPublic: BeforeInliningTarget,
-             cPublic: AtInliningTarget,
-             dPublic: BetweenTargets,
-             ePublic: AtDeploymentTarget,
-             fPublic: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  public var aPublicInit: Any = NoAvailable(),
-             bPublicInit: Any = BeforeInliningTarget(),
-             cPublicInit: Any = AtInliningTarget(),
-             dPublicInit: Any = BetweenTargets(),
-             ePublicInit: Any = AtDeploymentTarget(),
-             fPublicInit: Any = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  var aInternal: NoAvailable = .init(),
-      bInternal: BeforeInliningTarget = .init(),
-      cInternal: AtInliningTarget = .init(),
-      dInternal: BetweenTargets = .init(),
-      eInternal: AtDeploymentTarget = .init(),
-      fInternal: AfterDeploymentTarget = .init() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-}
-
-internal struct InternalStruct { // expected-note 2 {{add @available attribute}}
-  // Internal declarations act like non-inlinable.
-  var aInternal: NoAvailable = .init(),
-      bInternal: BeforeInliningTarget = .init(),
-      cInternal: AtInliningTarget = .init(),
-      dInternal: BetweenTargets = .init(),
-      eInternal: AtDeploymentTarget = .init(),
-      fInternal: AfterDeploymentTarget = .init() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @PropertyWrapper(NoAvailable()) var aWrapped: Any
-  @PropertyWrapper(BeforeInliningTarget()) var bWrapped: Any
-  @PropertyWrapper(AtInliningTarget()) var cWrapped: Any
-  @PropertyWrapper(BetweenTargets()) var dWrapped: Any
-  @PropertyWrapper(AtDeploymentTarget()) var eWrapped: Any
-  @PropertyWrapper(AfterDeploymentTarget()) var fWrapped: Any // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-}
-
-
-// MARK: - Extensions
-
-//
-// Extensions are externally visible if they extend a public type and (1) have
-// public members or (2) declare a conformance to a public protocol.
-//
-// Extensions without explicit availability that are externally visible use an
-// implied floor of either the availability of the extended type or the
-// deployment target, whichever is more available. This is a special rule
-// designed as a convenience to library authors who have written quite a bit of
-// code without annotating availability on their extensions and getting away
-// with it because previously the deployment target was always used as the
-// floor.
-//
-// Extensions without explicit availability that are not visible externally are
-// checked using an implied floor of the deployment target.
-//
-
-
-// MARK: Extensions on NoAvailable
-
-extension NoAvailable {}
-
-extension NoAvailable { // expected-note {{add @available attribute to enclosing extension}}
-  func internalFuncInExtension( // expected-note {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-extension NoAvailable { // expected-note 3 {{add @available attribute to enclosing extension}}
-  public func publicFuncInExtension( // expected-note 3 {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets, // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-    _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-// MARK: Extensions on BetweenTargets
-
-extension BetweenTargets {}
-
-extension BetweenTargets { // expected-note {{add @available attribute to enclosing extension}}
-  func internalFuncInExtension( // expected-note {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-extension BetweenTargets { // expected-note 2 {{add @available attribute to enclosing extension}}
-  public func publicFuncInExtension( // expected-note 2 {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-@available(macOS 10.15, *)
-extension BetweenTargets {
-  public func publicFuncInExtensionWithExplicitAvailability( // expected-note {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-extension BetweenTargets { // expected-note {{add @available attribute to enclosing extension}}
-  @available(macOS 10.15, *)
-  public func publicFuncWithExplicitAvailabilityInExtension(
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-@_spi(Private)
-extension BetweenTargets { // expected-note {{add @available attribute to enclosing extension}}
-  public func inheritedSPIFuncInExtension( // expected-note {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-@available(macOS, unavailable)
-extension BetweenTargets {
-  public func inheritsUnavailableFuncInExtension(
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget,
-    _: Unavailable
-  ) {}
-}
-
-// This extension is explicitly more available than BetweenTargets but because
-// it only contains internal members, the availability floor is still the
-// deployment target.
-@available(macOS 10.10, *)
-extension BetweenTargets {
-  func internalFuncInExcessivelyAvailableExtension() {}
-}
-
-extension BetweenTargets {
-  @available(macOS 10.10, *) // expected-warning {{instance method cannot be more available than enclosing scope}}
-  func excessivelyAvailableInternalFuncInExtension() {}
-}
-
-@available(macOS 10.10, *)
-extension BetweenTargets { // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  public func publicFuncInExcessivelyAvailableExtension() {}
-}
-
-// MARK: Extensions on BetweenTargetsInternal
-
-// Same availability as BetweenTargets but internal instead of public.
-@available(macOS 10.14.5, *)
-internal struct BetweenTargetsInternal {}
-
-extension BetweenTargetsInternal {}
-
-extension BetweenTargetsInternal { // expected-note {{add @available attribute to enclosing extension}}
-  func internalFuncInExtension( // expected-note {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-extension BetweenTargetsInternal { // expected-note {{add @available attribute to enclosing extension}}
-  public func publicFuncInExtension( // expected-note {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-// MARK: Extensions on AfterDeploymentTarget
-
-// expected-error@+1 {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note@+1 {{add @available attribute to enclosing extension}}
-extension AfterDeploymentTarget {}
-
-// expected-error@+1 {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-extension AfterDeploymentTarget { // expected-note 2 {{add @available attribute to enclosing extension}}
-  func internalFuncInExtension( // expected-note {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-// expected-error@+1 {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-extension AfterDeploymentTarget { // expected-note 2 {{add @available attribute to enclosing extension}}
-  public func publicFuncInExtension( // expected-note {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-@available(macOS 11, *)
-extension AfterDeploymentTarget {
-  public func publicFuncInExtensionWithExplicitAvailability(
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget
-  ) {}
-}
-
-// MARK: Extensions on nested types
-
-@available(macOS 10.14.5, *)
-public enum BetweenTargetsEnum {
-  public struct Nested {}
-}
-
-extension BetweenTargetsEnum.Nested {}
-
-extension BetweenTargetsEnum.Nested { // expected-note {{add @available attribute to enclosing extension}}
-  func internalFuncInExtension( // expected-note {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget,
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-extension BetweenTargetsEnum.Nested { // expected-note 2 {{add @available attribute to enclosing extension}}
-  public func publicFuncInExtension( // expected-note 2 {{add @available attribute to enclosing instance method}}
-    _: NoAvailable,
-    _: BeforeInliningTarget,
-    _: AtInliningTarget,
-    _: BetweenTargets,
-    _: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-    _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-  ) {}
-}
-
-// MARK: Protocol conformances
-
-internal protocol InternalProto {}
-
-extension NoAvailable: InternalProto {}
-extension BeforeInliningTarget: InternalProto {}
-extension AtInliningTarget: InternalProto {}
-extension BetweenTargets: InternalProto {}
-extension AtDeploymentTarget: InternalProto {}
-extension AfterDeploymentTarget: InternalProto {} // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add @available attribute to enclosing extension}}
-
-public protocol PublicProto {}
-
-extension NoAvailable: PublicProto {}
-extension BeforeInliningTarget: PublicProto {}
-extension AtInliningTarget: PublicProto {}
-extension BetweenTargets: PublicProto {}
-extension AtDeploymentTarget: PublicProto {}
-extension AfterDeploymentTarget: PublicProto {} // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add @available attribute to enclosing extension}}
-
-
-// MARK: - Associated types
-
-public protocol NoAvailableProtoWithAssoc { // expected-note 3 {{add @available attribute to enclosing protocol}}
-  associatedtype A: NoAvailableProto
-  associatedtype B: BeforeInliningTargetProto
-  associatedtype C: AtInliningTargetProto
-  associatedtype D: BetweenTargetsProto // expected-error {{'BetweenTargetsProto' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-  associatedtype E: AtDeploymentTargetProto // expected-error {{'AtDeploymentTargetProto' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-}
-
-@available(macOS 10.9, *)
-public protocol BeforeInliningTargetProtoWithAssoc {
-  associatedtype A: NoAvailableProto
-  associatedtype B: BeforeInliningTargetProto
-  associatedtype C: AtInliningTargetProto
-  associatedtype D: BetweenTargetsProto // expected-error {{'BetweenTargetsProto' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-  associatedtype E: AtDeploymentTargetProto // expected-error {{'AtDeploymentTargetProto' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-}
-
-@available(macOS 10.10, *)
-public protocol AtInliningTargetProtoWithAssoc {
-  associatedtype A: NoAvailableProto
-  associatedtype B: BeforeInliningTargetProto
-  associatedtype C: AtInliningTargetProto
-  associatedtype D: BetweenTargetsProto // expected-error {{'BetweenTargetsProto' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-  associatedtype E: AtDeploymentTargetProto // expected-error {{'AtDeploymentTargetProto' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-}
-
-@available(macOS 10.14.5, *)
-public protocol BetweenTargetsProtoWithAssoc {
-  associatedtype A: NoAvailableProto
-  associatedtype B: BeforeInliningTargetProto
-  associatedtype C: AtInliningTargetProto
-  associatedtype D: BetweenTargetsProto
-  associatedtype E: AtDeploymentTargetProto // expected-error {{'AtDeploymentTargetProto' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-}
-
-@available(macOS 10.15, *)
-public protocol AtDeploymentTargetProtoWithAssoc {
-  associatedtype A: NoAvailableProto
-  associatedtype B: BeforeInliningTargetProto
-  associatedtype C: AtInliningTargetProto
-  associatedtype D: BetweenTargetsProto
-  associatedtype E: AtDeploymentTargetProto
-  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-}
-
-@available(macOS 11, *)
-public protocol AfterDeploymentTargetProtoWithAssoc {
-  associatedtype A: NoAvailableProto
-  associatedtype B: BeforeInliningTargetProto
-  associatedtype C: AtInliningTargetProto
-  associatedtype D: BetweenTargetsProto
-  associatedtype E: AtDeploymentTargetProto
-  associatedtype F: AfterDeploymentTargetProto
-}
-
-@available(macOS, unavailable)
-public protocol UnavailableProtoWithAssoc {
-  associatedtype A: NoAvailableProto
-  associatedtype B: BeforeInliningTargetProto
-  associatedtype C: AtInliningTargetProto
-  associatedtype D: BetweenTargetsProto
-  associatedtype E: AtDeploymentTargetProto
-  associatedtype F: AfterDeploymentTargetProto
-  associatedtype G: UnavailableProto
-}
-
-@_spi(Private)
-public protocol SPINoAvailableProtoWithAssoc { // expected-note 1 {{add @available attribute to enclosing protocol}}
-  associatedtype A: NoAvailableProto
-  associatedtype B: BeforeInliningTargetProto
-  associatedtype C: AtInliningTargetProto
-  associatedtype D: BetweenTargetsProto
-  associatedtype E: AtDeploymentTargetProto
-  associatedtype F: AfterDeploymentTargetProto // expected-error {{'AfterDeploymentTargetProto' is only available in}}
-  // expected-note@-1{{add @available attribute to enclosing associated type}}
-}
-
-// MARK: - Type aliases
-
-public enum PublicNoAvailableEnumWithTypeAliases { // expected-note 3 {{add @available attribute to enclosing enum}}
-  public typealias A = NoAvailable
-  public typealias B = BeforeInliningTarget
-  public typealias C = AtInliningTarget
-  public typealias D = BetweenTargets // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add @available attribute to enclosing type alias}}
-  public typealias E = AtDeploymentTarget // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note {{add @available attribute to enclosing type alias}}
-  public typealias F = AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add @available attribute to enclosing type alias}}
-}
-
-@available(macOS, unavailable)
-public enum UnavailableEnumWithTypeAliases {
-  public typealias A = NoAvailable
-  public typealias B = BeforeInliningTarget
-  public typealias C = AtInliningTarget
-  public typealias D = BetweenTargets
-  public typealias E = AtDeploymentTarget
-  public typealias F = AfterDeploymentTarget
-  public typealias G = Unavailable
-}
-
-@_spi(Private)
-public enum SPIEnumWithTypeAliases { // expected-note 1 {{add @available attribute to enclosing enum}}
-  public typealias A = NoAvailable
-  public typealias B = BeforeInliningTarget
-  public typealias C = AtInliningTarget
-  public typealias D = BetweenTargets
-  public typealias E = AtDeploymentTarget
-  public typealias F = AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add @available attribute to enclosing type alias}}
-}
-
-enum InternalNoAvailableEnumWithTypeAliases { // expected-note {{add @available attribute to enclosing enum}}
-  public typealias A = NoAvailable
-  public typealias B = BeforeInliningTarget
-  public typealias C = AtInliningTarget
-  public typealias D = BetweenTargets
-  public typealias E = AtDeploymentTarget
-  public typealias F = AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add @available attribute to enclosing type alias}}
-}
-
-// MARK: - Enums with payloads
-
-public enum PublicNoAvailableEnumWithPayloads { // expected-note 5 {{add @available attribute to enclosing enum}}
-  case aNoAvailable(NoAvailable),
-       bNoAvailable(BeforeInliningTarget),
-       cNoAvailable(AtInliningTarget),
-       dNoAvailable(BetweenTargets), // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
-       eNoAvailable(AtDeploymentTarget), // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
-       fNoAvailable(AfterDeploymentTarget) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @available(macOS, introduced: 10.15)
-  case aAtDeploymentTarget(NoAvailable),
-       bAtDeploymentTarget(BeforeInliningTarget),
-       cAtDeploymentTarget(AtInliningTarget),
-       dAtDeploymentTarget(BetweenTargets),
-       eAtDeploymentTarget(AtDeploymentTarget),
-       fAtDeploymentTarget(AfterDeploymentTarget) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @_spi(Private)
-  case aSPI(NoAvailable),
-       bSPI(BeforeInliningTarget),
-       cSPI(AtInliningTarget),
-       dSPI(BetweenTargets),
-       eSPI(AtDeploymentTarget),
-       fSPI(AfterDeploymentTarget) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
-
-  @available(macOS, unavailable)
-  case aUnavailable(NoAvailable),
-       bUnavailable(BeforeInliningTarget),
-       cUnavailable(AtInliningTarget),
-       dUnavailable(BetweenTargets),
-       eUnavailable(AtDeploymentTarget),
-       fUnavailable(AfterDeploymentTarget)
-}
-
-// MARK: - Class inheritance
-
-// FIXME: Duplicate 'add @available' emitted when classes are nested in a decl
-
-public enum NoAvailableEnumWithClasses {
-  public class InheritsNoAvailable: NoAvailableClass {}
-  public class InheritsBeforeInliningTarget: BeforeInliningTargetClass {}
-  public class InheritsAtInliningTarget: AtInliningTargetClass {}
-  public class InheritsBetweenTargets: BetweenTargetsClass {} // expected-error {{'BetweenTargetsClass' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note 2 {{add @available attribute to enclosing class}}
-  public class InheritsAtDeploymentTarget: AtDeploymentTargetClass {} // expected-error {{'AtDeploymentTargetClass' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}} expected-note 2 {{add @available attribute to enclosing class}}
-  public class InheritsAfterDeploymentTarget: AfterDeploymentTargetClass {} // expected-error {{'AfterDeploymentTargetClass' is only available in macOS 11 or newer}} expected-note 2 {{add @available attribute to enclosing class}}
-  
-  @usableFromInline
-  class UFIInheritsBetweenTargets: BetweenTargetsClass {} // expected-error {{'BetweenTargetsClass' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}} expected-note 2 {{add @available attribute to enclosing class}}
-}
-
-@_spi(Private)
-public enum SPIEnumWithClasses {
-  public class InheritsNoAvailable: NoAvailableClass {}
-  public class InheritsBeforeInliningTarget: BeforeInliningTargetClass {}
-  public class InheritsAtInliningTarget: AtInliningTargetClass {}
-  public class InheritsBetweenTargets: BetweenTargetsClass {}
-  public class InheritsAtDeploymentTarget: AtDeploymentTargetClass {}
-  // FIXME: Duplicate 'add @available' note is emitted
-  public class InheritsAfterDeploymentTarget: AfterDeploymentTargetClass {} // expected-error {{'AfterDeploymentTargetClass' is only available in}} expected-note 2 {{add @available attribute to enclosing class}}
-}
-
-@available(macOS, unavailable)
-public enum UnavailableEnumWithClasses {
-  public class InheritsNoAvailable: NoAvailableClass {}
-  public class InheritsBeforeInliningTarget: BeforeInliningTargetClass {}
-  public class InheritsAtInliningTarget: AtInliningTargetClass {}
-  public class InheritsBetweenTargets: BetweenTargetsClass {}
-  public class InheritsAtDeploymentTarget: AtDeploymentTargetClass {}
-  public class InheritsAfterDeploymentTarget: AfterDeploymentTargetClass {}
-  public class InheritsUnavailable: UnavailableClass {}
-}
-
-// MARK: - Overrides
-
-public class Base {
-  @available(macOS 10.9, *)
-  public func beforeInliningTargetMethod() {} // expected-note 3 {{overridden declaration is here}}
-
-  @available(macOS 10.10, *)
-  public func atInliningTargetMethod() {}// expected-note 3 {{overridden declaration is here}}
-
-  @available(macOS 10.14.5, *)
-  public func betweenTargetsMethod() {}// expected-note 3 {{overridden declaration is here}}
-
-  @available(macOS 10.15, *)
-  public func atDeploymentTargetMethod() {}// expected-note 2 {{overridden declaration is here}}
-
-  @available(macOS 11, *)
-  public func afterDeploymentTargetMethod() {}// expected-note {{overridden declaration is here}}
-}
-
-public class DerivedNoAvailable: Base {
-  public override func beforeInliningTargetMethod() {}
-  public override func atInliningTargetMethod() {}
-  public override func betweenTargetsMethod() {}
-  public override func atDeploymentTargetMethod() {}
-  public override func afterDeploymentTargetMethod() {}
-}
-
-@available(macOS 10.9, *)
-public class DerivedBeforeInliningTarget: Base {
-  @available(macOS 10.9, *)
-  public override func beforeInliningTargetMethod() {}
-  @available(macOS 10.9, *)
-  public override func atInliningTargetMethod() {}
-  @available(macOS 10.9, *)
-  public override func betweenTargetsMethod() {}
-  @available(macOS 10.9, *)
-  public override func atDeploymentTargetMethod() {}
-  @available(macOS 10.9, *)
-  public override func afterDeploymentTargetMethod() {}
-}
-
-@available(macOS 10.10, *)
-public class DerivedAtInliningTarget: Base {
-  @available(macOS 10.10, *)
-  public override func beforeInliningTargetMethod() {}
-  @available(macOS 10.10, *)
-  public override func atInliningTargetMethod() {}
-  @available(macOS 10.10, *)
-  public override func betweenTargetsMethod() {}
-  @available(macOS 10.10, *)
-  public override func atDeploymentTargetMethod() {}
-  @available(macOS 10.10, *)
-  public override func afterDeploymentTargetMethod() {}
-}
-
-@available(macOS 10.14.5, *)
-public class DerivedBetweenTargets: Base {
-  @available(macOS 10.14.5, *)
-  public override func beforeInliningTargetMethod() {}
-  @available(macOS 10.14.5, *)
-  public override func atInliningTargetMethod() {}
-  @available(macOS 10.14.5, *)
-  public override func betweenTargetsMethod() {}
-  @available(macOS 10.14.5, *)
-  public override func atDeploymentTargetMethod() {}
-  @available(macOS 10.14.5, *)
-  public override func afterDeploymentTargetMethod() {}
-}
-
-@available(macOS 10.15, *)
-public class DerivedAtDeploymentTarget: Base {
-  @available(macOS 10.15, *)
-  public override func beforeInliningTargetMethod() {}
-  @available(macOS 10.15, *)
-  public override func atInliningTargetMethod() {}
-  @available(macOS 10.15, *)
-  public override func betweenTargetsMethod() {}
-  @available(macOS 10.15, *)
-  public override func atDeploymentTargetMethod() {}
-  @available(macOS 10.15, *)
-  public override func afterDeploymentTargetMethod() {}
-}
-
-@available(macOS 11, *)
-public class DerivedAfterDeploymentTarget: Base {
-  @available(macOS 11, *)
-  public override func beforeInliningTargetMethod() {}
-  @available(macOS 11, *)
-  public override func atInliningTargetMethod() {}
-  @available(macOS 11, *)
-  public override func betweenTargetsMethod() {}
-  @available(macOS 11, *)
-  public override func atDeploymentTargetMethod() {}
-  @available(macOS 11, *)
-  public override func afterDeploymentTargetMethod() {}
-}
-
-public class DerivedAtDeploymentTargetOverrides: Base {
-  @available(macOS 10.15, *)
-  public override func beforeInliningTargetMethod() {} // expected-error {{overriding 'beforeInliningTargetMethod' must be as available as declaration it overrides}}
-
-  @available(macOS 10.15, *)
-  public override func atInliningTargetMethod() {} // expected-error {{overriding 'atInliningTargetMethod' must be as available as declaration it overrides}}
-
-  @available(macOS 10.15, *)
-  public override func betweenTargetsMethod() {} // expected-error {{overriding 'betweenTargetsMethod' must be as available as declaration it overrides}}
-
-  @available(macOS 10.15, *)
-  public override func atDeploymentTargetMethod() {}
-
-  @available(macOS 10.15, *)
-  public override func afterDeploymentTargetMethod() {}
-}
-
-public class DerivedFutureOverrides: Base {
-  @available(macOS 12, *)
-  public override func beforeInliningTargetMethod() {} // expected-error {{overriding 'beforeInliningTargetMethod' must be as available as declaration it overrides}}
-
-  @available(macOS 12, *)
-  public override func atInliningTargetMethod() {} // expected-error {{overriding 'atInliningTargetMethod' must be as available as declaration it overrides}}
-
-  @available(macOS 12, *)
-  public override func betweenTargetsMethod() {} // expected-error {{overriding 'betweenTargetsMethod' must be as available as declaration it overrides}}
-
-  @available(macOS 12, *)
-  public override func atDeploymentTargetMethod() {} // expected-error {{overriding 'atDeploymentTargetMethod' must be as available as declaration it overrides}}
-
-  @available(macOS 12, *)
-  public override func afterDeploymentTargetMethod() {} // expected-error {{overriding 'afterDeploymentTargetMethod' must be as available as declaration it overrides}}
-}
-
-extension AtDeploymentTarget {
-  public class DerivedAtDeploymentTargetOverrides: Base {
-    @available(macOS 10.15, *)
-    public override func beforeInliningTargetMethod() {}
-
-    @available(macOS 10.15, *)
-    public override func atInliningTargetMethod() {}
-
-    @available(macOS 10.15, *)
-    public override func betweenTargetsMethod() {}
-
-    @available(macOS 10.15, *)
-    public override func atDeploymentTargetMethod() {}
-
-    @available(macOS 10.15, *)
-    public override func afterDeploymentTargetMethod() {}
-  }
-
-  public class DerivedAfterDeploymentTargetOverrides: Base {
-    @available(macOS 11, *)
-    public override func beforeInliningTargetMethod() {} // expected-error {{overriding 'beforeInliningTargetMethod' must be as available as declaration it overrides}}
-
-    @available(macOS 11, *)
-    public override func atInliningTargetMethod() {} // expected-error {{overriding 'atInliningTargetMethod' must be as available as declaration it overrides}}
-
-    @available(macOS 11, *)
-    public override func betweenTargetsMethod() {} // expected-error {{overriding 'betweenTargetsMethod' must be as available as declaration it overrides}}
-
-    @available(macOS 11, *)
-    public override func atDeploymentTargetMethod() {} // expected-error {{overriding 'atDeploymentTargetMethod' must be as available as declaration it overrides}}
-
-    @available(macOS 11, *)
-    public override func afterDeploymentTargetMethod() {}
-  }
-}
diff --git a/test/attr/attr_marker_protocol.swift b/test/attr/attr_marker_protocol.swift
index 25fe424f0380e..02700ee15bd2f 100644
--- a/test/attr/attr_marker_protocol.swift
+++ b/test/attr/attr_marker_protocol.swift
@@ -70,4 +70,4 @@ extension Array: P10 where Element: P10, Element: P8 { }
 // expected-error@-1{{conditional conformance to non-marker protocol 'P10' cannot depend on conformance of 'Element' to marker protocol 'P8'}}
 
 @objc @_marker protocol P11 {}
-// expected-error@-1 {{only classes (and their extensions), non-marker protocols, methods, initializers, properties, and subscript declarations can be declared @objc}}
+// expected-error@-1 {{only classes (and their extensions), non-marker protocols, methods, initializers, properties, and subscript declarations can be declared '@objc'}}
diff --git a/test/attr/attr_noescape.swift b/test/attr/attr_noescape.swift
index 8bd3e5e227e42..ba253fe15235b 100644
--- a/test/attr/attr_noescape.swift
+++ b/test/attr/attr_noescape.swift
@@ -32,16 +32,16 @@ func takesNoEscapeClosure(_ fn : () -> Int) { // expected-note 1 {{parameter 'fn
   // This is ok, because the closure itself is noescape.
   takesNoEscapeClosure { fn() }
 
-  doesEscape(fn)                   // expected-error {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
+  doesEscape(fn)                   // expected-error {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
   takesGenericClosure(4, fn)       // ok
   takesGenericClosure(4) { fn() }  // ok.
 
-  _ = [fn] // expected-error {{using non-escaping parameter 'fn' in a context expecting an @escaping closure}}
-  _ = [doesEscape(fn)] // expected-error {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
-  _ = [1 : fn] // expected-error {{using non-escaping parameter 'fn' in a context expecting an @escaping closure}}
-  _ = [1 : doesEscape(fn)] // expected-error {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
-  _ = "\(doesEscape(fn))" // expected-error {{passing non-escaping parameter 'fn' to function expecting an @escaping closure}}
-  _ = "\(takesArray([fn]))" // expected-error {{using non-escaping parameter 'fn' in a context expecting an @escaping closure}}
+  _ = [fn] // expected-error {{using non-escaping parameter 'fn' in a context expecting an '@escaping' closure}}
+  _ = [doesEscape(fn)] // expected-error {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
+  _ = [1 : fn] // expected-error {{using non-escaping parameter 'fn' in a context expecting an '@escaping' closure}}
+  _ = [1 : doesEscape(fn)] // expected-error {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
+  _ = "\(doesEscape(fn))" // expected-error {{passing non-escaping parameter 'fn' to function expecting an '@escaping' closure}}
+  _ = "\(takesArray([fn]))" // expected-error {{using non-escaping parameter 'fn' in a context expecting an '@escaping' closure}}
 
   assignToGlobal(fn) // expected-error {{converting non-escaping parameter 'fn' to generic parameter 'T' may allow it to escape}}
   assignToGlobal((fn, fn)) // expected-error {{converting non-escaping value to 'T' may allow it to escape}}
@@ -190,7 +190,7 @@ func takeNoEscapeTest2(_ fn : @noescape () -> ()) {  // expected-error{{unknown
 
 // Autoclosure implies noescape..
 func testAutoclosure(_ a : @autoclosure () -> Int) { // expected-note{{parameter 'a' is implicitly non-escaping}}
-  doesEscape(a)  // expected-error {{passing non-escaping parameter 'a' to function expecting an @escaping closure}}
+  doesEscape(a)  // expected-error {{passing non-escaping parameter 'a' to function expecting an '@escaping' closure}}
 }
 
 
@@ -212,7 +212,7 @@ func overloadedEach<P: P2, T>(_ source: P, _ transform: @escaping (P.Element) ->
 struct S : P2 {
   typealias Element = Int
   func each(_ transform: @noescape (Int) -> ()) { // expected-error{{unknown attribute 'noescape'}} expected-note {{parameter 'transform' is implicitly non-escaping}}
-    overloadedEach(self, transform, 1) // expected-error {{passing non-escaping parameter 'transform' to function expecting an @escaping closure}}
+    overloadedEach(self, transform, 1) // expected-error {{passing non-escaping parameter 'transform' to function expecting an '@escaping' closure}}
   }
 }
 
@@ -273,7 +273,7 @@ func curriedFlatMap2<A, B>(_ x: [A]) -> (@noescape (A) -> [B]) -> [B] { // expec
 func bad(_ a : @escaping (Int)-> Int) -> Int { return 42 }
 func escapeNoEscapeResult(_ x: [Int]) -> (@noescape (Int) -> Int) -> Int { // expected-error{{unknown attribute 'noescape'}}
   return { f in // expected-note {{parameter 'f' is implicitly non-escaping}} 
-    bad(f) // expected-error {{passing non-escaping parameter 'f' to function expecting an @escaping closure}}
+    bad(f) // expected-error {{passing non-escaping parameter 'f' to function expecting an '@escaping' closure}}
   }
 }
 
@@ -285,7 +285,7 @@ func escapeNoEscapeResult(_ x: [Int]) -> (@noescape (Int) -> Int) -> Int { // ex
 typealias CompletionHandlerNE = @noescape (_ success: Bool) -> () // expected-error{{unknown attribute 'noescape'}}
 
 // Explicit @escaping is not allowed here
-typealias CompletionHandlerE = @escaping (_ success: Bool) -> () // expected-error{{@escaping attribute may only be used in function parameter position}} {{32-42=}}
+typealias CompletionHandlerE = @escaping (_ success: Bool) -> () // expected-error{{'@escaping' may only be used in function parameter position}} {{32-42=}}
 
 // No @escaping -- it's implicit from context
 typealias CompletionHandler = (_ success: Bool) -> ()
@@ -293,13 +293,13 @@ typealias CompletionHandler = (_ success: Bool) -> ()
 var escape : CompletionHandlerNE
 var escapeOther : CompletionHandler
 func doThing1(_ completion: (_ success: Bool) -> ()) { // expected-note {{parameter 'completion' is implicitly non-escaping}}
-  escape = completion // expected-error {{assigning non-escaping parameter 'completion' to an @escaping closure}}
+  escape = completion // expected-error {{assigning non-escaping parameter 'completion' to an '@escaping' closure}}
 }
 func doThing2(_ completion: CompletionHandlerNE) { // expected-note {{parameter 'completion' is implicitly non-escaping}} 
-  escape = completion // expected-error {{assigning non-escaping parameter 'completion' to an @escaping closure}}
+  escape = completion // expected-error {{assigning non-escaping parameter 'completion' to an '@escaping' closure}}
 }
 func doThing3(_ completion: CompletionHandler) { // expected-note {{parameter 'completion' is implicitly non-escaping}}
-  escape = completion // expected-error {{assigning non-escaping parameter 'completion' to an @escaping closure}}
+  escape = completion // expected-error {{assigning non-escaping parameter 'completion' to an '@escaping' closure}}
 }
 func doThing4(_ completion: @escaping CompletionHandler) {
   escapeOther = completion
diff --git a/test/attr/attr_nonexhaustive.swift b/test/attr/attr_nonexhaustive.swift
new file mode 100644
index 0000000000000..5829e38df1f2f
--- /dev/null
+++ b/test/attr/attr_nonexhaustive.swift
@@ -0,0 +1,47 @@
+// RUN: %target-typecheck-verify-swift
+
+@nonexhaustive
+public enum E1 { // Ok
+}
+
+@nonexhaustive // expected-error {{'@nonexhaustive' attribute can only be applied to public or package declarations, but 'E2' is fileprivate}}
+fileprivate enum E2 {}
+
+@nonexhaustive // expected-error {{cannot use '@nonexhaustive' together with '@frozen'}}
+@frozen
+public enum E3 {
+}
+
+@nonexhaustive  // expected-error {{'@nonexhaustive' attribute can only be applied to public or package declarations, but 'E4' is internal}}
+@usableFromInline
+enum E4 {}
+
+@nonexhaustive // expected-error {{@nonexhaustive may only be used on 'enum' declarations}}
+struct Test {
+  @nonexhaustive // expected-error {{@nonexhaustive may only be used on 'enum' declarations}}
+  var v: Int {
+    @nonexhaustive // expected-error {{@nonexhaustive may only be used on 'enum' declarations}}
+    get { 0 }
+  }
+
+  @nonexhaustive // expected-error {{@nonexhaustive may only be used on 'enum' declarations}}
+  var v2: String = ""
+  
+  @nonexhaustive // expected-error {{@nonexhaustive may only be used on 'enum' declarations}}
+  func test() {}
+
+  @nonexhaustive // expected-error {{@nonexhaustive may only be used on 'enum' declarations}}
+  subscript(a: Int) -> Bool {
+    get { false }
+    set { }
+  }
+}
+
+@nonexhaustive(warn)
+public enum PE {
+}
+
+@nonexhaustive // expected-note {{attribute already specified here}}
+@nonexhaustive(warn) // expected-error {{duplicate attribute}}
+public enum WrongPreE {
+}
diff --git a/test/attr/attr_nonobjc.swift b/test/attr/attr_nonobjc.swift
index 53a683848a03c..0a37217fc605b 100644
--- a/test/attr/attr_nonobjc.swift
+++ b/test/attr/attr_nonobjc.swift
@@ -50,21 +50,21 @@ class NonObjCDeallocNotAllowed {
 @objc protocol ObjCProtocol {
   func protocolMethod() // expected-note {{}}
 
-  @nonobjc func nonObjCProtocolMethodNotAllowed() // expected-error {{declaration is a member of an @objc protocol, and cannot be marked @nonobjc}}
+  @nonobjc func nonObjCProtocolMethodNotAllowed() // expected-error {{declaration is a member of an '@objc' protocol, and cannot be marked '@nonobjc'}}
 
-  @nonobjc subscript(index: Int) -> Int { get } // expected-error {{declaration is a member of an @objc protocol, and cannot be marked @nonobjc}}
+  @nonobjc subscript(index: Int) -> Int { get } // expected-error {{declaration is a member of an '@objc' protocol, and cannot be marked '@nonobjc'}}
 
-  var surfaceArea: Float { @nonobjc get } // expected-error {{declaration is implicitly @objc, and cannot be marked @nonobjc}}
+  var surfaceArea: Float { @nonobjc get } // expected-error {{declaration is implicitly '@objc', and cannot be marked '@nonobjc'}}
 
   var displacement: Float { get }
 }
 
 class SillyClass {
-  @objc var description: String { @nonobjc get { return "" } } // expected-error {{declaration is implicitly @objc, and cannot be marked @nonobjc}}
+  @objc var description: String { @nonobjc get { return "" } } // expected-error {{declaration is implicitly '@objc', and cannot be marked '@nonobjc'}}
 }
 
 class ObjCAndNonObjCNotAllowed {
-  @objc @nonobjc func redundantAttributes() { } // expected-error {{declaration is marked @objc, and cannot be marked @nonobjc}}
+  @objc @nonobjc func redundantAttributes() { } // expected-error {{declaration is marked '@objc', and cannot be marked '@nonobjc'}}
 }
 
 class DynamicAndNonObjCAreFineNow {
@@ -72,14 +72,14 @@ class DynamicAndNonObjCAreFineNow {
 }
 
 class IBOutletAndNonObjCNotAllowed {
-  @nonobjc @IBOutlet var leeloo : String? = "Hello world" // expected-error {{declaration is marked @IBOutlet, and cannot be marked @nonobjc}}
+  @nonobjc @IBOutlet var leeloo : String? = "Hello world" // expected-error {{declaration is marked '@IBOutlet', and cannot be marked '@nonobjc'}}
 }
 
 class NSManagedAndNonObjCNotAllowed {
-  @nonobjc @NSManaged var rosie : NSObject // expected-error {{declaration is marked @NSManaged, and cannot be marked @nonobjc}}
+  @nonobjc @NSManaged var rosie : NSObject // expected-error {{declaration is marked '@NSManaged', and cannot be marked '@nonobjc'}}
 }
 
-@nonobjc func nonObjCTopLevelFuncNotAllowed() { } // expected-error {{only class members and extensions of classes can be declared @nonobjc}} {{1-10=}}
+@nonobjc func nonObjCTopLevelFuncNotAllowed() { } // expected-error {{only class members and extensions of classes can be declared '@nonobjc'}} {{1-10=}}
 
 @objc class NonObjCPropertyObjCProtocolNotAllowed : ObjCProtocol { // expected-error {{does not conform to protocol}} expected-note {{add stubs for conformance}}
   @nonobjc func protocolMethod() { } // expected-note {{candidate is explicitly '@nonobjc'}}
@@ -91,7 +91,7 @@ class NSManagedAndNonObjCNotAllowed {
   }
 
   var displacement: Float {
-    @nonobjc get { // expected-error {{declaration is implicitly @objc, and cannot be marked @nonobjc}}
+    @nonobjc get { // expected-error {{declaration is implicitly '@objc', and cannot be marked '@nonobjc'}}
       return Float(self[10])
     }
   }
@@ -104,13 +104,13 @@ class NSManagedAndNonObjCNotAllowed {
 }
 
 struct SomeStruct { }
-@nonobjc extension SomeStruct { } // expected-error{{only extensions of classes can be declared @nonobjc}}
+@nonobjc extension SomeStruct { } // expected-error{{only extensions of classes can be declared '@nonobjc'}}
 
 // https://github.com/apple/swift/issues/46809
 
 protocol P_46809 : class {}
 extension P_46809 {
-  @nonobjc func function() {} // expected-error {{only class members and extensions of classes can be declared @nonobjc}}
+  @nonobjc func function() {} // expected-error {{only class members and extensions of classes can be declared '@nonobjc'}}
 }
 
 @objc enum SomeEnum: Int {
diff --git a/test/attr/attr_objc.swift b/test/attr/attr_objc.swift
index 089cac96676a9..aeca130f9eb1f 100644
--- a/test/attr/attr_objc.swift
+++ b/test/attr/attr_objc.swift
@@ -92,24 +92,24 @@ class FáncyName {}
 @objc(FancyName)
 extension FáncyName {}
 
-@objc // bad-access-note-move{{subject_globalVar}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+@objc // bad-access-note-move{{subject_globalVar}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
 var subject_globalVar: Int
 
 var subject_getterSetter: Int {
-  @objc // bad-access-note-move{{getter:subject_getterSetter()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{getter:subject_getterSetter()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   get {
     return 0
   }
-  @objc // bad-access-note-move{{setter:subject_getterSetter()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{setter:subject_getterSetter()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   set {
   }
 }
 
 var subject_global_observingAccessorsVar1: Int = 0 {
-  @objc // expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   willSet {
   }
-  @objc // expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   didSet {
   }
 }
@@ -159,24 +159,24 @@ class subject_staticVar1 {
   class var staticVar2: Int { return 42 }
 }
 
-@objc // bad-access-note-move{{subject_freeFunc()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{1-7=}}
+@objc // bad-access-note-move{{subject_freeFunc()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{1-7=}}
 func subject_freeFunc() {
-  @objc // expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   var subject_localVar: Int
   // expected-warning@-1 {{variable 'subject_localVar' was never used; consider replacing with '_' or removing it}}
 
-  @objc // expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   func subject_nestedFreeFunc() {
   }
 }
 
-@objc // bad-access-note-move{{subject_genericFunc(t:)}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{1-7=}}
+@objc // bad-access-note-move{{subject_genericFunc(t:)}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{1-7=}}
 func subject_genericFunc<T>(t: T) {
-  @objc // expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   var subject_localVar: Int
   // expected-warning@-1 {{variable 'subject_localVar' was never used; consider replacing with '_' or removing it}}
 
-  @objc // expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   func subject_instanceFunc() {}
 }
 
@@ -185,25 +185,25 @@ func subject_funcParam(a: @objc Int) { // expected-error {{attribute can only be
 
 @objc // bad-access-note-move{{subject_struct}} expected-error {{'@objc' attribute cannot be applied to this declaration}} {{1-7=}}
 struct subject_struct {
-  @objc // bad-access-note-move{{subject_struct.subject_instanceVar}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{subject_struct.subject_instanceVar}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   var subject_instanceVar: Int
 
-  @objc // bad-access-note-move{{subject_struct.init()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{subject_struct.init()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   init() {}
 
-  @objc // bad-access-note-move{{subject_struct.subject_instanceFunc()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{subject_struct.subject_instanceFunc()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   func subject_instanceFunc() {}
 }
 
 @objc // bad-access-note-move{{subject_genericStruct}} expected-error {{'@objc' attribute cannot be applied to this declaration}} {{1-7=}}
 struct subject_genericStruct<T> {
-  @objc // bad-access-note-move{{subject_genericStruct.subject_instanceVar}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{subject_genericStruct.subject_instanceVar}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   var subject_instanceVar: Int
 
-  @objc // bad-access-note-move{{subject_genericStruct.init()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{subject_genericStruct.init()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   init() {}
 
-  @objc // bad-access-note-move{{subject_genericStruct.subject_instanceFunc()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{subject_genericStruct.subject_instanceFunc()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   func subject_instanceFunc() {}
 }
 
@@ -251,7 +251,7 @@ class subject_genericClass2<T> : Class_ObjC1 {
 
 extension subject_genericClass where T : Hashable {
   @objc // bad-access-note-move{{subject_genericClass.prop}}
-  var prop: Int { return 0 } // access-note-adjust{{@objc}} expected-error{{members of constrained extensions cannot be declared @objc}}
+  var prop: Int { return 0 } // access-note-adjust{{@objc}} expected-error{{members of constrained extensions cannot be declared '@objc'}}
 }
 
 extension subject_genericClass {
@@ -285,10 +285,10 @@ enum subject_enum: Int {
   @nonobjc // expected-error {{'@nonobjc' attribute cannot be applied to this declaration}}
   case subject_enumElement7
 
-  @objc // bad-access-note-move{{subject_enum.init()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{subject_enum.init()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   init() {}
 
-  @objc // bad-access-note-move{{subject_enum.subject_instanceFunc()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}} {{3-9=}}
+  @objc // bad-access-note-move{{subject_enum.subject_instanceFunc()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}} {{3-9=}}
   func subject_instanceFunc() {}
 }
 
@@ -315,48 +315,48 @@ protocol subject_protocol3 {}
 // CHECK-LABEL: @objc protocol subject_protocol3 {
 
 @objc // access-note-move{{subject_protocol4}}
-protocol subject_protocol4 : PlainProtocol {} // expected-error {{@objc protocol 'subject_protocol4' cannot refine non-@objc protocol 'PlainProtocol'}}
+protocol subject_protocol4 : PlainProtocol {} // expected-error {{'@objc' protocol 'subject_protocol4' cannot refine non-'@objc' protocol 'PlainProtocol'}}
 
 @objc // access-note-move{{subject_protocol5}}
-protocol subject_protocol5 : Protocol_Class1 {} // expected-error {{@objc protocol 'subject_protocol5' cannot refine non-@objc protocol 'Protocol_Class1'}}
+protocol subject_protocol5 : Protocol_Class1 {} // expected-error {{'@objc' protocol 'subject_protocol5' cannot refine non-'@objc' protocol 'Protocol_Class1'}}
 
 @objc // access-note-move{{subject_protocol6}}
 protocol subject_protocol6 : Protocol_ObjC1 {}
 
 protocol subject_containerProtocol1 {
-  @objc // bad-access-note-move{{subject_containerProtocol1.subject_instanceVar}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{subject_containerProtocol1.subject_instanceVar}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   var subject_instanceVar: Int { get }
 
-  @objc // bad-access-note-move{{subject_containerProtocol1.subject_instanceFunc()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{subject_containerProtocol1.subject_instanceFunc()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   func subject_instanceFunc()
 
-  @objc // bad-access-note-move{{subject_containerProtocol1.subject_staticFunc()}} expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{subject_containerProtocol1.subject_staticFunc()}} expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   static func subject_staticFunc()
 }
 
 @objc // access-note-move{{subject_containerObjCProtocol1}}
 protocol subject_containerObjCProtocol1 {
   func func_FunctionReturn1() -> PlainStruct
-  // expected-error@-1 {{method cannot be a member of an @objc protocol because its result type cannot be represented in Objective-C}}
+  // expected-error@-1 {{method cannot be a member of an '@objc' protocol because its result type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
   // expected-note@-3 {{inferring '@objc' because the declaration is a member of an '@objc' protocol}}
 
   func func_FunctionParam1(a: PlainStruct)
-  // expected-error@-1 {{method cannot be a member of an @objc protocol because the type of the parameter cannot be represented in Objective-C}}
+  // expected-error@-1 {{method cannot be a member of an '@objc' protocol because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
   // expected-note@-3 {{inferring '@objc' because the declaration is a member of an '@objc' protocol}}
 
   func func_Variadic(_: AnyObject...)
-  // expected-error @-1{{method cannot be a member of an @objc protocol because it has a variadic parameter}}
+  // expected-error @-1{{method cannot be a member of an '@objc' protocol because it has a variadic parameter}}
   // expected-note @-2{{inferring '@objc' because the declaration is a member of an '@objc' protocol}}
 
   subscript(a: PlainStruct) -> Int { get }
-  // expected-error@-1 {{subscript cannot be a member of an @objc protocol because its type cannot be represented in Objective-C}}
+  // expected-error@-1 {{subscript cannot be a member of an '@objc' protocol because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
   // expected-note@-3 {{inferring '@objc' because the declaration is a member of an '@objc' protocol}}
 
   var varNonObjC1: PlainStruct { get }
-  // expected-error@-1 {{property cannot be a member of an @objc protocol because its type cannot be represented in Objective-C}}
+  // expected-error@-1 {{property cannot be a member of an '@objc' protocol because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
   // expected-note@-3 {{inferring '@objc' because the declaration is a member of an '@objc' protocol}}
 }
@@ -396,7 +396,7 @@ extension subject_class1 {}
 // expected-warning@-1 {{extension with Objective-C category name 'ConflictingName' conflicts with previous extension with the same category name; this is an error in the Swift 6 language mode}}
 
 protocol nonObjCProtocol {
-  @objc // bad-access-note-move{{nonObjCProtocol.objcRequirement()}} expected-error{{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{nonObjCProtocol.objcRequirement()}} expected-error{{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   func objcRequirement()
 }
 
@@ -418,42 +418,42 @@ class ConcreteContext3 {
   func dynamicSelf1_() -> Self { return self }
 
   @objc // bad-access-note-move{{ConcreteContext3.genericParams()}}
-  func genericParams<T: NSObject>() -> [T] { return [] } // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked @objc because it has generic parameters}}
+  func genericParams<T: NSObject>() -> [T] { return [] } // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because it has generic parameters}}
 
   @objc // bad-access-note-move{{ConcreteContext3.returnObjCProtocolMetatype()}}
-  func returnObjCProtocolMetatype() -> NSCoding.Protocol { return NSCoding.self } // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  func returnObjCProtocolMetatype() -> NSCoding.Protocol { return NSCoding.self } // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
 
   typealias AnotherNSCoding = NSCoding
   typealias MetaNSCoding1 = NSCoding.Protocol
   typealias MetaNSCoding2 = AnotherNSCoding.Protocol
 
   @objc // bad-access-note-move{{ConcreteContext3.returnObjCAliasProtocolMetatype1()}}
-  func returnObjCAliasProtocolMetatype1() -> AnotherNSCoding.Protocol { return NSCoding.self } // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  func returnObjCAliasProtocolMetatype1() -> AnotherNSCoding.Protocol { return NSCoding.self } // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
 
   @objc // bad-access-note-move{{ConcreteContext3.returnObjCAliasProtocolMetatype2()}}
-  func returnObjCAliasProtocolMetatype2() -> MetaNSCoding1 { return NSCoding.self } // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  func returnObjCAliasProtocolMetatype2() -> MetaNSCoding1 { return NSCoding.self } // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
 
   @objc // bad-access-note-move{{ConcreteContext3.returnObjCAliasProtocolMetatype3()}}
-  func returnObjCAliasProtocolMetatype3() -> MetaNSCoding2 { return NSCoding.self } // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  func returnObjCAliasProtocolMetatype3() -> MetaNSCoding2 { return NSCoding.self } // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
 
   typealias Composition = NSCopying & NSCoding
 
   @objc // bad-access-note-move{{ConcreteContext3.returnCompositionMetatype1()}}
-  func returnCompositionMetatype1() -> Composition.Protocol { return Composition.self } // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  func returnCompositionMetatype1() -> Composition.Protocol { return Composition.self } // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
 
   @objc // bad-access-note-move{{ConcreteContext3.returnCompositionMetatype2()}}
-  func returnCompositionMetatype2() -> (NSCopying & NSCoding).Protocol { return (NSCopying & NSCoding).self } // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  func returnCompositionMetatype2() -> (NSCopying & NSCoding).Protocol { return (NSCopying & NSCoding).self } // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
 
   typealias NSCodingExistential = NSCoding.Type
 
   @objc // bad-access-note-move{{ConcreteContext3.inoutFunc(a:)}}
-  func inoutFunc(a: inout Int) {} // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because inout parameters cannot be represented in Objective-C}}
+  func inoutFunc(a: inout Int) {} // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because inout parameters cannot be represented in Objective-C}}
 
   @objc // bad-access-note-move{{ConcreteContext3.metatypeOfExistentialMetatypePram1(a:)}}
-  func metatypeOfExistentialMetatypePram1(a: NSCodingExistential.Protocol) {} // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  func metatypeOfExistentialMetatypePram1(a: NSCodingExistential.Protocol) {} // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
 
   @objc // bad-access-note-move{{ConcreteContext3.metatypeOfExistentialMetatypePram2(a:)}}
-  func metatypeOfExistentialMetatypePram2(a: NSCoding.Type.Protocol) {} // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  func metatypeOfExistentialMetatypePram2(a: NSCoding.Type.Protocol) {} // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
 }
 
 func genericContext1<T>(_: T) {
@@ -505,7 +505,7 @@ class GenericContext3<T> {
 
 class GenericContext4<T> {
   @objc // bad-access-note-move{{GenericContext4.foo()}}
-  func foo() where T: Hashable { } // access-note-adjust{{@objc}} expected-error {{instance method cannot be marked @objc because it has a 'where' clause}}
+  func foo() where T: Hashable { } // access-note-adjust{{@objc}} expected-error {{instance method cannot be marked '@objc' because it has a 'where' clause}}
 }
 
 @objc // bad-access-note-move{{ConcreteSubclassOfGeneric}} expected-error{{generic subclasses of '@objc' classes cannot have an explicit '@objc' because they are not directly visible from Objective-C}} {{1-7=}}
@@ -610,7 +610,7 @@ class subject_subscriptGeneric<T> {
 
 class subject_subscriptInvalid1 {
   @objc // bad-access-note-move{{subject_subscriptInvalid1.subscript(_:)}}
-  class subscript(_ i: Int) -> AnyObject? { // access-note-adjust{{@objc}} expected-error {{class subscript cannot be marked @objc}}
+  class subscript(_ i: Int) -> AnyObject? { // access-note-adjust{{@objc}} expected-error {{class subscript cannot be marked '@objc'}}
     return nil
   }
 }
@@ -618,48 +618,48 @@ class subject_subscriptInvalid1 {
 class subject_subscriptInvalid2 {
   @objc // bad-access-note-move{{subject_subscriptInvalid2.subscript(_:)}}
   subscript(a: PlainClass) -> Int {
-  // access-note-adjust{{@objc}} expected-error@-1 {{subscript cannot be marked @objc because its type cannot be represented in Objective-C}}
-  // expected-note@-2 {{classes not annotated with @objc cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{subscript cannot be marked '@objc' because its type cannot be represented in Objective-C}}
+  // expected-note@-2 {{classes not annotated with '@objc' cannot be represented in Objective-C}}
     get { return 0 }
   }
 }
 class subject_subscriptInvalid3 {
   @objc // bad-access-note-move{{subject_subscriptInvalid3.subscript(_:)}}
-  subscript(a: PlainClass.Type) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked @objc because its type cannot be represented in Objective-C}}
+  subscript(a: PlainClass.Type) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked '@objc' because its type cannot be represented in Objective-C}}
     get { return 0 }
   }
 }
 class subject_subscriptInvalid4 {
   @objc // bad-access-note-move{{subject_subscriptInvalid4.subscript(_:)}}
-  subscript(a: PlainStruct) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked @objc because its type cannot be represented in Objective-C}}
+  subscript(a: PlainStruct) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked '@objc' because its type cannot be represented in Objective-C}}
     // expected-note@-1{{Swift structs cannot be represented in Objective-C}}
     get { return 0 }
   }
 }
 class subject_subscriptInvalid5 {
   @objc // bad-access-note-move{{subject_subscriptInvalid5.subscript(_:)}}
-  subscript(a: PlainEnum) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked @objc because its type cannot be represented in Objective-C}}
+  subscript(a: PlainEnum) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked '@objc' because its type cannot be represented in Objective-C}}
     // expected-note@-1{{enums cannot be represented in Objective-C}}
     get { return 0 }
   }
 }
 class subject_subscriptInvalid6 {
   @objc // bad-access-note-move{{subject_subscriptInvalid6.subscript(_:)}}
-  subscript(a: PlainProtocol) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked @objc because its type cannot be represented in Objective-C}}
+  subscript(a: PlainProtocol) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked '@objc' because its type cannot be represented in Objective-C}}
     // expected-note@-1{{protocol-constrained type containing protocol 'PlainProtocol' cannot be represented in Objective-C}}
     get { return 0 }
   }
 }
 class subject_subscriptInvalid7 {
   @objc // bad-access-note-move{{subject_subscriptInvalid7.subscript(_:)}}
-  subscript(a: Protocol_Class1) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked @objc because its type cannot be represented in Objective-C}}
+  subscript(a: Protocol_Class1) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked '@objc' because its type cannot be represented in Objective-C}}
     // expected-note@-1{{protocol-constrained type containing protocol 'Protocol_Class1' cannot be represented in Objective-C}}
     get { return 0 }
   }
 }
 class subject_subscriptInvalid8 {
   @objc // bad-access-note-move{{subject_subscriptInvalid8.subscript(_:)}}
-  subscript(a: Protocol_Class1 & Protocol_Class2) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked @objc because its type cannot be represented in Objective-C}}
+  subscript(a: Protocol_Class1 & Protocol_Class2) -> Int { // access-note-adjust{{@objc}} expected-error {{subscript cannot be marked '@objc' because its type cannot be represented in Objective-C}}
     // expected-note@-1{{protocol-constrained type containing protocol 'Protocol_Class1' cannot be represented in Objective-C}}
     get { return 0 }
   }
@@ -667,7 +667,7 @@ class subject_subscriptInvalid8 {
 
 class subject_propertyInvalid1 {
   @objc // bad-access-note-move{{subject_propertyInvalid1.plainStruct}}
-  let plainStruct = PlainStruct() // access-note-adjust{{@objc}} expected-error {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  let plainStruct = PlainStruct() // access-note-adjust{{@objc}} expected-error {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-1{{Swift structs cannot be represented in Objective-C}}
 }
 
@@ -718,37 +718,37 @@ class infer_instanceFunc1 {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func7_(a:)}}
   func func7_(a: PlainClass) {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
-  // expected-note@-2 {{classes not annotated with @objc cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
+  // expected-note@-2 {{classes not annotated with '@objc' cannot be represented in Objective-C}}
 
   func func7m(a: PlainClass.Type) {}
 // CHECK-LABEL: {{^}} func func7m(a: PlainClass.Type) {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func7m_(a:)}}
   func func7m_(a: PlainClass.Type) {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
 
   func func8() -> PlainClass {}
 // CHECK-LABEL: {{^}} func func8() -> PlainClass {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func8_()}}
   func func8_() -> PlainClass {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
-  // expected-note@-2 {{classes not annotated with @objc cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
+  // expected-note@-2 {{classes not annotated with '@objc' cannot be represented in Objective-C}}
 
   func func8m() -> PlainClass.Type {}
 // CHECK-LABEL: {{^}} func func8m() -> PlainClass.Type {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func8m_()}}
   func func8m_() -> PlainClass.Type {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
 
   func func9(a: PlainStruct) {}
 // CHECK-LABEL: {{^}} func func9(a: PlainStruct) {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func9_(a:)}}
   func func9_(a: PlainStruct) {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   func func10() -> PlainStruct {}
@@ -756,7 +756,7 @@ class infer_instanceFunc1 {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func10_()}}
   func func10_() -> PlainStruct {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   func func11(a: PlainEnum) {}
@@ -764,7 +764,7 @@ class infer_instanceFunc1 {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func11_(a:)}}
   func func11_(a: PlainEnum) {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{non-'@objc' enums cannot be represented in Objective-C}}
 
   func func12(a: PlainProtocol) {}
@@ -772,7 +772,7 @@ class infer_instanceFunc1 {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func12_(a:)}}
   func func12_(a: PlainProtocol) {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'PlainProtocol' cannot be represented in Objective-C}}
 
   func func13(a: Class_ObjC1) {}
@@ -786,7 +786,7 @@ class infer_instanceFunc1 {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func14_(a:)}}
   func func14_(a: Protocol_Class1) {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'Protocol_Class1' cannot be represented in Objective-C}}
 
   func func15(a: Protocol_ObjC1) {}
@@ -878,9 +878,9 @@ class infer_instanceFunc1 {
   // Check that we produce diagnostics for every parameter and return type.
   @objc // bad-access-note-move{{infer_instanceFunc1.func_MultipleDiags(a:b:)}}
   func func_MultipleDiags(a: PlainStruct, b: PlainEnum) -> Any {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because the type of the parameter 1 cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because the type of the parameter 1 cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
-  // access-note-adjust{{@objc}} expected-error@-3 {{method cannot be marked @objc because the type of the parameter 2 cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-3 {{instance method cannot be marked '@objc' because the type of the parameter 2 cannot be represented in Objective-C}}
   // expected-note@-4 {{non-'@objc' enums cannot be represented in Objective-C}}
   // Produces an extra: expected-note@-5 * {{attribute 'objc' was added by access note for fancy tests}}
 
@@ -889,7 +889,7 @@ class infer_instanceFunc1 {
 
   @objc // bad-access-note-move{{infer_instanceFunc1.func_UnnamedParam2(_:)}}
   func func_UnnamedParam2(_: PlainStruct) {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   @objc // access-note-move{{infer_instanceFunc1.func_varParam1(a:)}}
@@ -955,7 +955,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.instanceVar1_}}
   var (instanceVar1_, instanceVar2_): (Int, PlainProtocol)
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'PlainProtocol' cannot be represented in Objective-C}}
   // Fake for access notes: @objc // access-note-move@-3{{infer_instanceVar1.instanceVar2_}}
 
@@ -1031,7 +1031,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_tuple1_}}
   var var_tuple1_: ()
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{empty tuple type cannot be represented in Objective-C}}
 
   var var_tuple2: Void
@@ -1039,7 +1039,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_tuple2_}}
   var var_tuple2_: Void
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{empty tuple type cannot be represented in Objective-C}}
 
   var var_tuple3: (Int)
@@ -1053,7 +1053,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_tuple4_}}
   var var_tuple4_: (Int, Int)
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{tuples cannot be represented in Objective-C}}
 
   //===--- Stdlib integer types.
@@ -1084,15 +1084,15 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_PlainClass_}}
   var var_PlainClass_: PlainClass
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
-  // expected-note@-2 {{classes not annotated with @objc cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
+  // expected-note@-2 {{classes not annotated with '@objc' cannot be represented in Objective-C}}
 
   var var_PlainStruct: PlainStruct
 // CHECK-LABEL: {{^}}  var var_PlainStruct: PlainStruct
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_PlainStruct_}}
   var var_PlainStruct_: PlainStruct
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   var var_PlainEnum: PlainEnum
@@ -1100,7 +1100,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_PlainEnum_}}
   var var_PlainEnum_: PlainEnum
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{non-'@objc' enums cannot be represented in Objective-C}}
 
   var var_PlainProtocol: PlainProtocol
@@ -1108,7 +1108,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_PlainProtocol_}}
   var var_PlainProtocol_: PlainProtocol
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'PlainProtocol' cannot be represented in Objective-C}}
 
   var var_ClassObjC: Class_ObjC1
@@ -1122,7 +1122,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ProtocolClass_}}
   var var_ProtocolClass_: Protocol_Class1
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'Protocol_Class1' cannot be represented in Objective-C}}
 
   var var_ProtocolObjC: Protocol_ObjC1
@@ -1137,28 +1137,28 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_PlainClassMetatype_}}
   var var_PlainClassMetatype_: PlainClass.Type
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
 
   var var_PlainStructMetatype: PlainStruct.Type
 // CHECK-LABEL: {{^}}  var var_PlainStructMetatype: PlainStruct.Type
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_PlainStructMetatype_}}
   var var_PlainStructMetatype_: PlainStruct.Type
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
 
   var var_PlainEnumMetatype: PlainEnum.Type
 // CHECK-LABEL: {{^}}  var var_PlainEnumMetatype: PlainEnum.Type
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_PlainEnumMetatype_}}
   var var_PlainEnumMetatype_: PlainEnum.Type
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
 
   var var_PlainExistentialMetatype: PlainProtocol.Type
 // CHECK-LABEL: {{^}}  var var_PlainExistentialMetatype: any PlainProtocol.Type
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_PlainExistentialMetatype_}}
   var var_PlainExistentialMetatype_: PlainProtocol.Type
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
 
   var var_ClassObjCMetatype: Class_ObjC1.Type
 // CHECK-LABEL: {{^}}  var var_ClassObjCMetatype: Class_ObjC1.Type
@@ -1171,7 +1171,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ProtocolClassMetatype_}}
   var var_ProtocolClassMetatype_: Protocol_Class1.Type
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
 
   var var_ProtocolObjCMetatype1: Protocol_ObjC1.Type
 // CHECK-LABEL: {{^}}  var var_ProtocolObjCMetatype1: any Protocol_ObjC1.Type
@@ -1201,7 +1201,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_Existential1_}}
   var var_Existential1_: PlainProtocol
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'PlainProtocol' cannot be represented in Objective-C}}
 
   var var_Existential2: PlainProtocol & PlainProtocol
@@ -1209,7 +1209,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_Existential2_}}
   var var_Existential2_: PlainProtocol & PlainProtocol
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'PlainProtocol' cannot be represented in Objective-C}}
 
   var var_Existential3: PlainProtocol & Protocol_Class1
@@ -1217,7 +1217,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_Existential3_}}
   var var_Existential3_: PlainProtocol & Protocol_Class1
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'PlainProtocol' cannot be represented in Objective-C}}
 
   var var_Existential4: PlainProtocol & Protocol_ObjC1
@@ -1225,7 +1225,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_Existential4_}}
   var var_Existential4_: PlainProtocol & Protocol_ObjC1
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'PlainProtocol' cannot be represented in Objective-C}}
 
   var var_Existential5: Protocol_Class1
@@ -1233,7 +1233,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_Existential5_}}
   var var_Existential5_: Protocol_Class1
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'Protocol_Class1' cannot be represented in Objective-C}}
 
   var var_Existential6: Protocol_Class1 & Protocol_Class2
@@ -1241,7 +1241,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_Existential6_}}
   var var_Existential6_: Protocol_Class1 & Protocol_Class2
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'Protocol_Class1' cannot be represented in Objective-C}}
 
   var var_Existential7: Protocol_Class1 & Protocol_ObjC1
@@ -1249,7 +1249,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_Existential7_}}
   var var_Existential7_: Protocol_Class1 & Protocol_ObjC1
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'Protocol_Class1' cannot be represented in Objective-C}}
 
   var var_Existential8: Protocol_ObjC1
@@ -1393,7 +1393,7 @@ class infer_instanceVar1 {
   // CHECK-LABEL: {{^}}  var var_CFunctionPointer_1: @convention(c) () -> ()
   var var_CFunctionPointer_1: @convention(c) () -> ()
   // CHECK-LABEL: {{^}}  var var_CFunctionPointer_invalid_1: Int
-  var var_CFunctionPointer_invalid_1: @convention(c) Int // expected-error {{@convention attribute only applies to function types}}
+  var var_CFunctionPointer_invalid_1: @convention(c) Int // expected-error {{'@convention' only applies to function types}}
   // CHECK-LABEL: {{^}} var var_CFunctionPointer_invalid_2: <<error type>>
   var var_CFunctionPointer_invalid_2: @convention(c) (PlainStruct) -> Int // expected-error {{'(PlainStruct) -> Int' is not representable in Objective-C, so it cannot be used with '@convention(c)'}}
   
@@ -1566,7 +1566,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ArrayType3_}}
   var var_ArrayType3_: [PlainStruct]
-  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   var var_ArrayType4: [(AnyObject) -> AnyObject] // no-error
@@ -1574,7 +1574,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ArrayType4_}}
   var var_ArrayType4_: [(AnyObject) -> AnyObject]
-  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   var var_ArrayType5: [Protocol_ObjC1]
@@ -1594,7 +1594,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ArrayType7_}}
   var var_ArrayType7_: [PlainClass]
-  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   var var_ArrayType8: [PlainProtocol]
@@ -1602,7 +1602,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ArrayType8_}}
   var var_ArrayType8_: [PlainProtocol]
-  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   var var_ArrayType9: [Protocol_ObjC1 & PlainProtocol]
@@ -1610,7 +1610,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ArrayType9_}}
   var var_ArrayType9_: [Protocol_ObjC1 & PlainProtocol]
-  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   var var_ArrayType10: [Protocol_ObjC1 & Protocol_ObjC2]
@@ -1631,7 +1631,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ArrayType13_}}
   var var_ArrayType13_: [Any?]
-  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   var var_ArrayType15: [AnyObject?]
@@ -1639,7 +1639,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ArrayType15_}}
   var var_ArrayType15_: [AnyObject?]
-  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   var var_ArrayType16: [[@convention(block) (AnyObject) -> AnyObject]] // no-error
@@ -1653,7 +1653,7 @@ class infer_instanceVar1 {
 
   @objc // bad-access-note-move{{infer_instanceVar1.var_ArrayType17_}}
   var var_ArrayType17_: [[(AnyObject) -> AnyObject]]
-  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error @-1{{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 }
 
@@ -1675,7 +1675,7 @@ class infer_instanceVar2<
 
   @objc // bad-access-note-move{{infer_instanceVar2.var_GP_Unconstrained_}}
   var var_GP_Unconstrained_: GP_Unconstrained
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{generic type parameters cannot be represented in Objective-C}}
 
   var var_GP_PlainClass: GP_PlainClass
@@ -1683,7 +1683,7 @@ class infer_instanceVar2<
 
   @objc // bad-access-note-move{{infer_instanceVar2.var_GP_PlainClass_}}
   var var_GP_PlainClass_: GP_PlainClass
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{generic type parameters cannot be represented in Objective-C}}
 
   var var_GP_PlainProtocol: GP_PlainProtocol
@@ -1691,7 +1691,7 @@ class infer_instanceVar2<
 
   @objc // bad-access-note-move{{infer_instanceVar2.var_GP_PlainProtocol_}}
   var var_GP_PlainProtocol_: GP_PlainProtocol
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{generic type parameters cannot be represented in Objective-C}}
 
   var var_GP_Class_ObjC: GP_Class_ObjC
@@ -1699,7 +1699,7 @@ class infer_instanceVar2<
 
   @objc // bad-access-note-move{{infer_instanceVar2.var_GP_Class_ObjC_}}
   var var_GP_Class_ObjC_: GP_Class_ObjC
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{generic type parameters cannot be represented in Objective-C}}
 
   var var_GP_Protocol_Class: GP_Protocol_Class
@@ -1707,7 +1707,7 @@ class infer_instanceVar2<
 
   @objc // bad-access-note-move{{infer_instanceVar2.var_GP_Protocol_Class_}}
   var var_GP_Protocol_Class_: GP_Protocol_Class
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{generic type parameters cannot be represented in Objective-C}}
 
   var var_GP_Protocol_ObjC: GP_Protocol_ObjC
@@ -1715,7 +1715,7 @@ class infer_instanceVar2<
 
   @objc // bad-access-note-move{{infer_instanceVar2.var_GP_Protocol_ObjCa}}
   var var_GP_Protocol_ObjCa: GP_Protocol_ObjC
-  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked @objc because its type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{property cannot be marked '@objc' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{generic type parameters cannot be represented in Objective-C}}
 
   func func_GP_Unconstrained(a: GP_Unconstrained) {}
@@ -1723,17 +1723,17 @@ class infer_instanceVar2<
 
   @objc // bad-access-note-move{{infer_instanceVar2.func_GP_Unconstrained_(a:)}}
   func func_GP_Unconstrained_(a: GP_Unconstrained) {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{generic type parameters cannot be represented in Objective-C}}
 
   @objc // bad-access-note-move{{infer_instanceVar2.func_GP_Unconstrained_()}}
   func func_GP_Unconstrained_() -> GP_Unconstrained {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
   // expected-note@-2 {{generic type parameters cannot be represented in Objective-C}}
 
   @objc // bad-access-note-move{{infer_instanceVar2.func_GP_Class_ObjC__()}}
   func func_GP_Class_ObjC__() -> GP_Class_ObjC {}
-  // access-note-adjust{{@objc}} expected-error@-1 {{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{instance method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
   // expected-note@-2 {{generic type parameters cannot be represented in Objective-C}}
 }
 
@@ -1875,8 +1875,8 @@ class HasIBOutlet {
   // CHECK-LABEL: {{^}} @objc @IBOutlet @_hasInitialValue weak var goodOutlet: @sil_weak Class_ObjC1!
 
   @IBOutlet var badOutlet: PlainStruct
-  // expected-error@-1 {{@IBOutlet property cannot have non-object type 'PlainStruct'}} {{3-13=}}
-  // expected-error@-2 {{@IBOutlet property has non-optional type 'PlainStruct'}}
+  // expected-error@-1 {{'@IBOutlet' property cannot have non-object type 'PlainStruct'}} {{3-13=}}
+  // expected-error@-2 {{'@IBOutlet' property has non-optional type 'PlainStruct'}}
   // expected-note@-3 {{add '?' to form the optional type 'PlainStruct?'}}
   // expected-note@-4 {{add '!' to form an implicitly unwrapped optional}}
   // CHECK-LABEL: {{^}}  @IBOutlet var badOutlet: PlainStruct
@@ -1892,7 +1892,7 @@ class HasIBAction {
   // CHECK: {{^}}  @objc @IBAction @MainActor @preconcurrency func goodAction(_ sender: AnyObject?) {
 
   @IBAction func badAction(_ sender: PlainStruct?) { }
-  // expected-error@-1{{method cannot be marked @IBAction because the type of the parameter cannot be represented in Objective-C}}
+  // expected-error@-1{{method cannot be marked '@IBAction' because the type of the parameter cannot be represented in Objective-C}}
 }
 
 //===---
@@ -1905,7 +1905,7 @@ class HasIBSegueAction {
   // CHECK: {{^}}  @objc @IBSegueAction func goodSegueAction(_ coder: AnyObject) -> AnyObject {
 
   @IBSegueAction func badSegueAction(_ coder: PlainStruct?) -> Int? {fatalError()}
-  // expected-error@-1{{method cannot be marked @IBSegueAction because the type of the parameter cannot be represented in Objective-C}}
+  // expected-error@-1{{method cannot be marked '@IBSegueAction' because the type of the parameter cannot be represented in Objective-C}}
 }
 
 //===---
@@ -1946,7 +1946,7 @@ class HasNSManaged {
 
   @NSManaged
   var badManaged: PlainStruct
-  // expected-error@-1 {{property cannot be marked @NSManaged because its type cannot be represented in Objective-C}}
+  // expected-error@-1 {{property cannot be marked '@NSManaged' because its type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
   // CHECK-LABEL: {{^}}  @NSManaged dynamic var badManaged: PlainStruct {
   // CHECK-NEXT: {{^}} get
@@ -1999,7 +1999,7 @@ class Class_ObjC2 {
   // CHECK-LABEL: @objc(isFoo) func foo() -> Bool {
 }
 
-@objc() // expected-error {{expected name within parentheses of @objc attribute}}
+@objc() // expected-error {{expected name within parentheses of '@objc'}}
 class Class_ObjC3 { 
 }
 
@@ -2016,8 +2016,8 @@ extension PlainClass {
   // CHECK-LABEL: @objc(createWithRed:green:blue:alpha:) dynamic class func createWith
   @objc(createWithRed:green blue:alpha)
   class func createWithRed(_: Float, green: Float, blue: Float, alpha: Float) { }
-  // expected-error@-2{{missing ':' after selector piece in @objc attribute}}{{28-28=:}}
-  // expected-error@-3{{missing ':' after selector piece in @objc attribute}}{{39-39=:}}
+  // expected-error@-2{{missing ':' after selector piece in '@objc'}}{{28-28=:}}
+  // expected-error@-3{{missing ':' after selector piece in '@objc'}}{{39-39=:}}
 
   // CHECK-LABEL: @objc(::) dynamic func badlyNamed
   @objc(::) // access-note-move{{PlainClass.badlyNamed(_:y:)}}
@@ -2125,7 +2125,7 @@ class Sub1 : Super {
   @objc(foo) // bad-access-note-move{{Sub1.foo}} expected-error{{Objective-C property has a different name from the property it overrides ('foo' vs. 'renamedFoo')}}{{9-12=renamedFoo}}
   override var foo: Int { get { return 5 } }
 
-  override func process(i: Int?) -> Int { } // expected-error{{method cannot be an @objc override because the type of the parameter cannot be represented in Objective-C}}
+  override func process(i: Int?) -> Int { } // expected-error{{method cannot be an '@objc' override because the type of the parameter cannot be represented in Objective-C}}
 }
 
 class Sub2 : Super {
@@ -2159,18 +2159,18 @@ class ClosureArguments {
   func foo(f: (Int) -> ()) {}
   // CHECK: @objc func bar
   @objc // bad-access-note-move{{ClosureArguments.bar(f:)}}
-  func bar(f: (NotObjCEnum) -> NotObjCStruct) {} // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
+  func bar(f: (NotObjCEnum) -> NotObjCStruct) {} // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
   // CHECK: @objc func bas
   @objc // bad-access-note-move{{ClosureArguments.bas(f:)}}
-  func bas(f: (NotObjCEnum) -> ()) {} // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
+  func bas(f: (NotObjCEnum) -> ()) {} // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
   // CHECK: @objc func zim
   @objc // bad-access-note-move{{ClosureArguments.zim(f:)}}
-  func zim(f: () -> NotObjCStruct) {} // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
+  func zim(f: () -> NotObjCStruct) {} // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
   // CHECK: @objc func zang
   @objc // bad-access-note-move{{ClosureArguments.zang(f:)}}
-  func zang(f: (NotObjCEnum, NotObjCStruct) -> ()) {} // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
+  func zang(f: (NotObjCEnum, NotObjCStruct) -> ()) {} // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
   @objc // bad-access-note-move{{ClosureArguments.zangZang(f:)}}
-  func zangZang(f: (Int...) -> ()) {} // access-note-adjust{{@objc}} expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
+  func zangZang(f: (Int...) -> ()) {} // access-note-adjust{{@objc}} expected-error{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}} expected-note{{function types cannot be represented in Objective-C unless their parameters and returns can be}}
   // CHECK: {{^}}  func fooImplicit
   func fooImplicit(f: (Int) -> ()) {}
   // CHECK: {{^}}  func barImplicit
@@ -2236,24 +2236,24 @@ class Load3 {
 // Members of protocol extensions cannot be @objc
 
 extension PlainProtocol {
-  @objc // bad-access-note-move{{PlainProtocol.property}} expected-error{{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{PlainProtocol.property}} expected-error{{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   var property: Int { return 5 }
 
-  @objc // bad-access-note-move{{PlainProtocol.subscript(_:)}} expected-error{{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{PlainProtocol.subscript(_:)}} expected-error{{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   subscript(x: Int) -> Class_ObjC1 { return Class_ObjC1() }
 
-  @objc // bad-access-note-move{{PlainProtocol.fun()}} expected-error{{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{PlainProtocol.fun()}} expected-error{{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   func fun() { }
 }
 
 extension Protocol_ObjC1 {
-  @objc // bad-access-note-move{{Protocol_ObjC1.property}} expected-error{{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{Protocol_ObjC1.property}} expected-error{{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   var property: Int { return 5 }
 
-  @objc // bad-access-note-move{{Protocol_ObjC1.subscript(_:)}} expected-error{{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{Protocol_ObjC1.subscript(_:)}} expected-error{{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   subscript(x: Int) -> Class_ObjC1 { return Class_ObjC1() }
 
-  @objc // bad-access-note-move{{Protocol_ObjC1.fun()}} expected-error{{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+  @objc // bad-access-note-move{{Protocol_ObjC1.fun()}} expected-error{{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
   func fun() { }
 }
 
@@ -2268,6 +2268,11 @@ extension Protocol_ObjC1 {
 //===---
 //===--- Error handling
 //===---
+enum ObjCError: Int, Error {
+  case Others
+}
+protocol MyError: Error { }
+
 // CHECK-LABEL: class ClassThrows1
 class ClassThrows1 {
   // CHECK: @objc func methodReturnsVoid() throws
@@ -2295,28 +2300,28 @@ class ClassThrows1 {
   // Errors
 
   @objc // bad-access-note-move{{ClassThrows1.methodReturnsOptionalObjCClass()}}
-  func methodReturnsOptionalObjCClass() throws -> Class_ObjC1? { return nil } // access-note-adjust{{@objc}} expected-error{{throwing method cannot be marked @objc because it returns a value of optional type 'Class_ObjC1?'; 'nil' indicates failure to Objective-C}}
+  func methodReturnsOptionalObjCClass() throws -> Class_ObjC1? { return nil } // access-note-adjust{{@objc}} expected-error{{throwing method cannot be marked '@objc' because it returns a value of optional type 'Class_ObjC1?'; 'nil' indicates failure to Objective-C}}
 
   @objc // bad-access-note-move{{ClassThrows1.methodReturnsOptionalArray()}}
-  func methodReturnsOptionalArray() throws -> [String]? { return nil } // access-note-adjust{{@objc}} expected-error{{throwing method cannot be marked @objc because it returns a value of optional type '[String]?'; 'nil' indicates failure to Objective-C}}
+  func methodReturnsOptionalArray() throws -> [String]? { return nil } // access-note-adjust{{@objc}} expected-error{{throwing method cannot be marked '@objc' because it returns a value of optional type '[String]?'; 'nil' indicates failure to Objective-C}}
 
   @objc // bad-access-note-move{{ClassThrows1.methodReturnsInt()}}
-  func methodReturnsInt() throws -> Int { return 0 } // access-note-adjust{{@objc}} expected-error{{throwing method cannot be marked @objc because it returns a value of type 'Int'; return 'Void' or a type that bridges to an Objective-C class}}
+  func methodReturnsInt() throws -> Int { return 0 } // access-note-adjust{{@objc}} expected-error{{throwing method cannot be marked '@objc' because it returns a value of type 'Int'; return 'Void' or a type that bridges to an Objective-C class}}
 
   @objc // bad-access-note-move{{ClassThrows1.methodAcceptsThrowingFunc(fn:)}}
   func methodAcceptsThrowingFunc(fn: (String) throws -> Int) { }
-  // access-note-adjust{{@objc}} expected-error@-1{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2{{throwing function types cannot be represented in Objective-C}}
 
   @objc // bad-access-note-move{{ClassThrows1.init(radians:)}}
-  init?(radians: Double) throws { } // access-note-adjust{{@objc}} expected-error{{a failable and throwing initializer cannot be marked @objc because 'nil' indicates failure to Objective-C}}
+  init?(radians: Double) throws { } // access-note-adjust{{@objc}} expected-error{{a failable and throwing initializer cannot be marked '@objc' because 'nil' indicates failure to Objective-C}}
 
   @objc // bad-access-note-move{{ClassThrows1.init(string:)}}
-  init!(string: String) throws { } // access-note-adjust{{@objc}} expected-error{{a failable and throwing initializer cannot be marked @objc because 'nil' indicates failure to Objective-C}}
+  init!(string: String) throws { } // access-note-adjust{{@objc}} expected-error{{a failable and throwing initializer cannot be marked '@objc' because 'nil' indicates failure to Objective-C}}
 
   @objc // bad-access-note-move{{ClassThrows1.fooWithErrorEnum1(x:)}}
   func fooWithErrorEnum1(x: ErrorEnum) {}
-  // access-note-adjust{{@objc}} expected-error@-1{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2{{non-'@objc' enums cannot be represented in Objective-C}}
 
   // CHECK: {{^}} func fooWithErrorEnum2(x: ErrorEnum)
@@ -2324,11 +2329,20 @@ class ClassThrows1 {
 
   @objc // bad-access-note-move{{ClassThrows1.fooWithErrorProtocolComposition1(x:)}}
   func fooWithErrorProtocolComposition1(x: Error & Protocol_ObjC1) { }
-  // access-note-adjust{{@objc}} expected-error@-1{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // access-note-adjust{{@objc}} expected-error@-1{{instance method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2{{protocol-constrained type containing 'Error' cannot be represented in Objective-C}}
 
   // CHECK: {{^}} func fooWithErrorProtocolComposition2(x: any Error & Protocol_ObjC1)
   func fooWithErrorProtocolComposition2(x: Error & Protocol_ObjC1) { }
+
+  @objc func throwsError() throws(Error) {}
+  @objc func throwsMyError() throws(MyError) {}
+  // expected-error@-1{{typed 'throws' instance method cannot be represented in Objective-C}}
+  // expected-error@-2{{thrown type 'any MyError' does not conform to the 'Error' protocol}}
+  @objc func throwsObjCError() throws(ObjCError) {}
+  // expected-error@-1{{typed 'throws' instance method cannot be represented in Objective-C}}
+  @objc static func throwsObjCErrorClass() throws(ObjCError) {}
+  // expected-error@-1{{typed 'throws' static method cannot be represented in Objective-C}}
 }
 
 
@@ -2374,7 +2388,7 @@ class ImplicitClassThrows1 {
   func methodReturnsBridgedValueType2() throws -> NSRange {
     return NSRange()
   }
-  // access-note-adjust{{@objc}} expected-error@-3{{throwing method cannot be marked @objc because it returns a value of type 'NSRange' (aka '_NSRange'); return 'Void' or a type that bridges to an Objective-C class}}
+  // access-note-adjust{{@objc}} expected-error@-3{{throwing method cannot be marked '@objc' because it returns a value of type 'NSRange' (aka '_NSRange'); return 'Void' or a type that bridges to an Objective-C class}}
 
   // CHECK: {{^}} func methodReturnsError() throws -> any Error
   func methodReturnsError() throws -> Error { return ErrorEnum.failed }
@@ -2504,7 +2518,7 @@ extension PlainClass {
   final func objc_ext_objc_okay(_: Int) { }
 
   final func objc_ext_objc_not_okay(_: PlainStruct) { }
-  // expected-error@-1{{method cannot be in an @objc extension of a class (without @nonobjc) because the type of the parameter cannot be represented in Objective-C}}
+  // expected-error@-1{{method cannot be in an '@objc' extension of a class (without '@nonobjc') because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   // CHECK-LABEL: {{^}} @nonobjc final func objc_ext_objc_explicit_nonobjc(_: PlainStruct) {
@@ -2529,19 +2543,19 @@ class OperatorInClass {
   }
   // CHECK: {{^}} @objc static func + (lhs: OperatorInClass, rhs: OperatorInClass) -> OperatorInClass
   @objc
-  static func +(lhs: OperatorInClass, rhs: OperatorInClass) -> OperatorInClass { // expected-error {{operator methods cannot be declared @objc}}
+  static func +(lhs: OperatorInClass, rhs: OperatorInClass) -> OperatorInClass { // expected-error {{operator methods cannot be declared '@objc'}}
     return lhs
   }
 } // CHECK: {{^}$}}
 
 @objc // access-note-move{{OperatorInProtocol}}
 protocol OperatorInProtocol {
-  static func +(lhs: Self, rhs: Self) -> Self // expected-error {{@objc protocols must not have operator requirements}}
+  static func +(lhs: Self, rhs: Self) -> Self // expected-error {{'@objc' protocols must not have operator requirements}}
 }
 
 class AdoptsOperatorInProtocol : OperatorInProtocol {
   static func +(lhs: AdoptsOperatorInProtocol, rhs: AdoptsOperatorInProtocol) -> Self {}
-  // expected-error@-1 {{operator methods cannot be declared @objc}}
+  // expected-error@-1 {{operator methods cannot be declared '@objc'}}
 }
 
 //===--- @objc inference for witnesses
@@ -2625,7 +2639,7 @@ extension User {
 	}
 
 	var other: String {
-    unsafeAddress { // expected-error {{addressors are not allowed to be marked @objc}}
+    unsafeAddress { // expected-error {{addressors are not allowed to be marked '@objc'}}
     }
   }
 }
@@ -2684,7 +2698,7 @@ class issue51538_C {}
 @objc // access-note-move{{issue51538_P}}
 protocol issue51538_P {
   func throwingMethod1() throws -> Unmanaged<CFArray> // Ok
-  func throwingMethod2() throws -> Unmanaged<issue51538_C> // expected-error {{method cannot be a member of an @objc protocol because its result type cannot be represented in Objective-C}}
+  func throwingMethod2() throws -> Unmanaged<issue51538_C> // expected-error {{method cannot be a member of an '@objc' protocol because its result type cannot be represented in Objective-C}}
   // expected-note@-1 {{inferring '@objc' because the declaration is a member of an '@objc' protocol}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 }
@@ -2694,5 +2708,5 @@ protocol issue51538_P {
 class issue55246 {
   @objc // bad-access-note-move{{issue55246.subscript(_:)}}
   subscript<T>(foo : [T]) -> Int { return 0 }
-  // access-note-adjust{{@objc}} expected-error@-1 {{subscript cannot be marked @objc because it has generic parameters}}
+  // access-note-adjust{{@objc}} expected-error@-1 {{subscript cannot be marked '@objc' because it has generic parameters}}
 }
diff --git a/test/attr/attr_objc_any.swift b/test/attr/attr_objc_any.swift
index ee8bd91832c9a..3e59b02dec8df 100644
--- a/test/attr/attr_objc_any.swift
+++ b/test/attr/attr_objc_any.swift
@@ -3,7 +3,7 @@
 
 import Foundation
 
-@objc var foo: Any // expected-error {{@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes}}
+@objc var foo: Any // expected-error {{'@objc' can only be used with members of classes, '@objc' protocols, and concrete extensions of classes}}
 
 class Foo: NSObject {
   override init() {}
@@ -17,5 +17,5 @@ class Foo: NSObject {
 
   @objc func throwingMethod(x: Any) throws -> Any { return x }
 
-  @objc func throwingMethod(x: Any) throws -> Any? { return x } // expected-error{{throwing method cannot be marked @objc because it returns a value of optional type 'Any?'; 'nil' indicates failure to Objective-C}}
+  @objc func throwingMethod(x: Any) throws -> Any? { return x } // expected-error{{throwing method cannot be marked '@objc' because it returns a value of optional type 'Any?'; 'nil' indicates failure to Objective-C}}
 }
diff --git a/test/attr/attr_objc_async.swift b/test/attr/attr_objc_async.swift
index e42f9d343ec15..f7c6d27278eb3 100644
--- a/test/attr/attr_objc_async.swift
+++ b/test/attr/attr_objc_async.swift
@@ -18,7 +18,7 @@ class MyClass {
   // CHECK-DUMP: (foreign_async_convention completion_handler_type="@convention(block) (Optional<AnyObject>, Int, Optional<any Error>) -> ()" completion_handler_param=1 error_param=2)
   @objc func doBigJobOrFailClass(_: Int) async throws -> (AnyObject, Int) { return (self, 0) }
 
-  @objc func takeAnAsync(_ fn: () async -> Int) { } // expected-error{{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  @objc func takeAnAsync(_ fn: () async -> Int) { } // expected-error{{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-1{{'async' function types cannot be represented in Objective-C}}
 
   @objc class func createAsynchronously() async -> Self? { nil }
@@ -27,6 +27,10 @@ class MyClass {
 
 // actor exporting Objective-C entry points.
 
+enum ObjCError: Int, Error {
+  case Others
+}
+
 // CHECK: actor MyActor
 actor MyActor {
   // CHECK: @objc func doBigJobActor() async -> Int
@@ -38,17 +42,21 @@ actor MyActor {
   // CHECK-DUMP-LABEL: func_decl{{.*}}doBigJobOrFailActor{{.*}}
   // CHECK-DUMP: (foreign_async_convention completion_handler_type="@convention(block) (Optional<AnyObject>, Int, Optional<any Error>) -> ()" completion_handler_param=1 error_param=2)
   @objc func doBigJobOrFailActor(_: Int) async throws -> (AnyObject, Int) { return (self, 0) }
-  // expected-warning@-1{{non-sendable type '(AnyObject, Int)' returned by actor-isolated '@objc' instance method 'doBigJobOrFailActor' cannot cross actor boundary}}
+  // expected-warning@-1{{non-Sendable type '(AnyObject, Int)' returned by actor-isolated '@objc' instance method 'doBigJobOrFailActor' cannot cross actor boundary}}
 
   // Actor-isolated entities cannot be exposed to Objective-C.
-  @objc func synchronousBad() { } // expected-error{{actor-isolated instance method 'synchronousBad()' cannot be @objc}}
+  @objc func synchronousBad() { } // expected-error{{actor-isolated instance method 'synchronousBad()' cannot be '@objc'}}
   // expected-note@-1{{add 'async' to function 'synchronousBad()' to make it asynchronous}} {{30-30= async}}
 
-  @objc var badProp: AnyObject { self } // expected-error{{actor-isolated property 'badProp' cannot be @objc}}
-  @objc subscript(index: Int) -> AnyObject { self } // expected-error{{actor-isolated subscript 'subscript(_:)' cannot be @objc}}
+  @objc var badProp: AnyObject { self } // expected-error{{actor-isolated property 'badProp' cannot be '@objc'}}
+  @objc subscript(index: Int) -> AnyObject { self } // expected-error{{actor-isolated subscript 'subscript(_:)' cannot be '@objc'}}
 
   // CHECK: @objc nonisolated func synchronousGood()
   @objc nonisolated func synchronousGood() { }
+
+  @objc func objcAsyncThrowsError() async throws(Error) -> Void {}
+  @objc func objcAsyncThrowsObjCError() async throws(ObjCError) -> Void {}
+  // expected-error@-1 {{typed 'throws' instance method cannot be represented in Objective-C}}
 }
 
 actor class MyActor2 { }
diff --git a/test/attr/attr_objc_foreign.swift b/test/attr/attr_objc_foreign.swift
index 98e033df8c669..2e679db3e0bb4 100644
--- a/test/attr/attr_objc_foreign.swift
+++ b/test/attr/attr_objc_foreign.swift
@@ -15,9 +15,9 @@ extension CGColor {
   // CHECK-LABEL: {{^}} subscript(x: CGColor) -> CGFloat
   subscript(x: CGColor) -> CGFloat { return 0 }
 
-  @objc var blue: CGFloat { return 0 } // expected-error{{method cannot be marked @objc because Core Foundation types are not classes in Objective-C}}
-  @objc func asHSV() -> CGColor { return self } // expected-error{{method cannot be marked @objc because Core Foundation types are not classes in Objective-C}}
-  @objc subscript(x: Int) -> CGFloat { return 0 } // expected-error{{method cannot be marked @objc because Core Foundation types are not classes in Objective-C}}
+  @objc var blue: CGFloat { return 0 } // expected-error{{method cannot be marked '@objc' because Core Foundation types are not classes in Objective-C}}
+  @objc func asHSV() -> CGColor { return self } // expected-error{{method cannot be marked '@objc' because Core Foundation types are not classes in Objective-C}}
+  @objc subscript(x: Int) -> CGFloat { return 0 } // expected-error{{method cannot be marked '@objc' because Core Foundation types are not classes in Objective-C}}
 }
 
 @objc protocol Foo {
@@ -25,8 +25,8 @@ extension CGColor {
 }
 
 // CHECK-LABEL: extension CGColor : Foo
-extension CGColor: Foo { // expected-error{{Core Foundation class 'CGColor' cannot conform to @objc protocol 'Foo' because Core Foundation types are not classes in Objective-C}}
+extension CGColor: Foo { // expected-error{{Core Foundation class 'CGColor' cannot conform to '@objc' protocol 'Foo' because Core Foundation types are not classes in Objective-C}}
   // CHECK-LABEL: {{^}} func foo()
-  func foo() {} // expected-error{{method cannot be an implementation of an @objc requirement because Core Foundation types are not classes in Objective-C}}
+  func foo() {} // expected-error{{method cannot be an implementation of an '@objc' requirement because Core Foundation types are not classes in Objective-C}}
 }
 
diff --git a/test/attr/attr_objc_overlays.swift b/test/attr/attr_objc_overlays.swift
index a4ddd1d4349d4..7ffb75266ec8c 100644
--- a/test/attr/attr_objc_overlays.swift
+++ b/test/attr/attr_objc_overlays.swift
@@ -8,7 +8,7 @@ struct NativeStruct {}
 
 class Test {
   @objc func invalid() -> NativeStruct { return NativeStruct() }
-  // expected-error@-1 {{method cannot be marked @objc because its result type cannot be represented in Objective-C}}
+  // expected-error@-1 {{method cannot be marked '@objc' because its result type cannot be represented in Objective-C}}
   // expected-note@-2 {{Swift structs cannot be represented in Objective-C}}
 
   @objc func selector(sel: Selector) {} // no-warning
diff --git a/test/attr/attr_objc_override.swift b/test/attr/attr_objc_override.swift
index 002241289d99c..f5c037caeff40 100644
--- a/test/attr/attr_objc_override.swift
+++ b/test/attr/attr_objc_override.swift
@@ -29,11 +29,11 @@ class B : A {
     get { return self }  // expected-error{{subscript getter with Objective-C selector 'objectForKeyedSubscript:' conflicts with subscript getter from superclass 'A'}}
   }
 
-  override func foo() { } // expected-error{{non-@objc instance method 'foo()' is declared in extension of 'A' and cannot be overridden}}
+  override func foo() { } // expected-error{{non-'@objc' instance method 'foo()' is declared in extension of 'A' and cannot be overridden}}
 
   override func wibble(_: SwiftStruct) { } // expected-error{{instance method 'wibble' is declared in extension of 'A' and cannot be overridden}}
 }
 
 extension B {
-  override func bar() { } // expected-error{{non-@objc instance method 'bar()' declared in 'A' cannot be overridden from extension}}
+  override func bar() { } // expected-error{{non-'@objc' instance method 'bar()' declared in 'A' cannot be overridden from extension}}
 }
diff --git a/test/attr/attr_objc_swift4.swift b/test/attr/attr_objc_swift4.swift
index 6e6dc0c1cef06..110d65e779066 100644
--- a/test/attr/attr_objc_swift4.swift
+++ b/test/attr/attr_objc_swift4.swift
@@ -25,10 +25,10 @@ struct PlainStruct { }
 
 class BadInSwift4 {
   @IBInspectable var badIBInspectable: PlainStruct?
-  // expected-error@-1{{property cannot be marked @IBInspectable because its type cannot be represented in Objective-C}}
+  // expected-error@-1{{property cannot be marked '@IBInspectable' because its type cannot be represented in Objective-C}}
 
   @GKInspectable var badGKInspectable: PlainStruct?
-  // expected-error@-1{{property cannot be marked @GKInspectable because its type cannot be represented in Objective-C}}
+  // expected-error@-1{{property cannot be marked '@GKInspectable' because its type cannot be represented in Objective-C}}
 }
 
 // CHECK-LABEL: class InitsInheritObjCAttrBase
diff --git a/test/attr/attr_specialize.swift b/test/attr/attr_specialize.swift
index 2971406bbbaf7..6363d2857e8ac 100644
--- a/test/attr/attr_specialize.swift
+++ b/test/attr/attr_specialize.swift
@@ -29,6 +29,7 @@ class NonSub {}
 @_specialize(where T == S<Int>)
 @_specialize(where T == Int, U == Int) // expected-error{{cannot find type 'U' in scope}},
 @_specialize(where T == T1) // expected-error{{cannot find type 'T1' in scope}}
+@specialized(where T == T1) // expected-error{{cannot find type 'T1' in scope}}
 public func oneGenericParam<T>(_ t: T) -> T {
   return t
 }
@@ -52,14 +53,17 @@ class G<T> {
   @_specialize(where T == T) // expected-error{{too few generic parameters are specified in '_specialize' attribute (got 0, but expected 1)}}
   // expected-note@-1 {{missing constraint for 'T' in '_specialize' attribute}}
   @_specialize(where T == S<T>)
-  // expected-error@-1 {{cannot build rewrite system for generic signature; concrete nesting limit exceeded}}
+  // expected-error@-1 {{cannot build rewrite system for generic signature; concrete type nesting limit exceeded}}
   // expected-note@-2 {{failed rewrite rule is τ_0_0.[concrete: S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<τ_0_0>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>] => τ_0_0}}
-  // expected-error@-3 {{too few generic parameters are specified in '_specialize' attribute (got 0, but expected 1)}}
-  // expected-note@-4 {{missing constraint for 'T' in '_specialize' attribute}}
   @_specialize(where T == Int, U == Int) // expected-error{{cannot find type 'U' in scope}}
 
   func noGenericParams() {}
 
+  @specialized(where T == Int)
+  @specialized(where T == T) // expected-error{{too few generic parameters are specified in 'specialized' attribute (got 0, but expected 1)}}
+  // expected-note@-1 {{missing constraint for 'T' in 'specialized' attribute}}
+  func noGenericParamsPublic() {}
+
   // CHECK: @_specialize(exported: false, kind: full, where T == Int, U == Float)
   @_specialize(where T == Int, U == Float)
   // CHECK: @_specialize(exported: false, kind: full, where T == Int, U == S<Int>)
@@ -68,7 +72,10 @@ class G<T> {
   func oneGenericParam<U>(_ t: T, u: U) -> (U, T) {
     return (u, t)
   }
-}
+  @specialized(where T == Int) // expected-error{{too few generic parameters are specified in 'specialized' attribute (got 1, but expected 2)}} expected-note {{missing constraint for 'U' in 'specialized' attribute}}
+  func oneGenericParamPublic<U>(_ t: T, u: U) -> (U, T) {
+    return (u, t)
+  }}
 
 // Specialize with requirements.
 // -----------------------------
@@ -96,8 +103,14 @@ struct FloatElement : HasElt {
 @_specialize(where T == IntElement) // expected-error{{generic signature requires types 'IntElement.Element' (aka 'Int') and 'Float' to be the same}}
 func sameTypeRequirement<T : HasElt>(_ t: T) where T.Element == Float {}
 
+@specialized(where T == FloatElement)
+@specialized(where T == IntElement) // expected-error{{generic signature requires types 'IntElement.Element' (aka 'Int') and 'Float' to be the same}}
+func sameTypeRequirementPublic<T : HasElt>(_ t: T) where T.Element == Float {}
+
 @_specialize(where T == Sub)
 @_specialize(where T == NonSub) // expected-error{{no type for 'T' can satisfy both 'T : NonSub' and 'T : Base'}}
+@specialized(where T == Sub)
+@specialized(where T == NonSub) // expected-error{{no type for 'T' can satisfy both 'T : NonSub' and 'T : Base'}}
 func superTypeRequirement<T : Base>(_ t: T) {}
 
 @_specialize(where X:_Trivial(8), Y == Int) // expected-error{{trailing 'where' clause in '_specialize' attribute of non-generic function 'requirementOnNonGenericFunction(x:y:)'}}
@@ -105,11 +118,13 @@ public func requirementOnNonGenericFunction(x: Int, y: Int) {
 }
 
 @_specialize(where Y == Int) // expected-error{{too few generic parameters are specified in '_specialize' attribute (got 1, but expected 2)}} expected-note{{missing constraint for 'X' in '_specialize' attribute}}
+@specialized(where Y == Int) // expected-error{{too few generic parameters are specified in 'specialized' attribute (got 1, but expected 2)}} expected-note{{missing constraint for 'X' in 'specialized' attribute}}
 public func missingRequirement<X:P, Y>(x: X, y: Y) {
 }
 
 @_specialize(where) // expected-error{{expected type}}
 @_specialize() // expected-error{{expected a parameter label or a where clause in '_specialize' attribute}} expected-error{{expected declaration}}
+@specialized() // expected-error{{expected a where clause in 'specialized' attribute}} expected-error{{expected declaration}}
 public func funcWithEmptySpecializeAttr<X: P, Y>(x: X, y: Y) {
 }
 
@@ -149,11 +164,12 @@ public func funcWithTwoGenericParameters<X, Y>(x: X, y: Y) {
 @_specialize(kind: partial, exported: true, where X == Int, Y == Int)
 @_specialize(kind: partial, kind: partial, where X == Int, Y == Int) // expected-error{{parameter 'kind' was already defined in '_specialize' attribute}}
 
-@_specialize(where X == Int, Y == Int, exported: true, kind: partial) // expected-error{{cannot find type 'exported' in scope}} expected-error{{cannot find type 'kind' in scope}} expected-error{{cannot find type 'partial' in scope}} expected-error{{expected type}}
+@_specialize(where X == Int, Y == Int, exported: true, kind: partial) // expected-error{{expected type}} expected-error{{cannot find type 'exported' in scope}} expected-error{{cannot find type 'kind' in scope}} expected-error{{cannot find type 'partial' in scope}}
 public func anotherFuncWithTwoGenericParameters<X: P, Y>(x: X, y: Y) {
 }
 
 @_specialize(where T: P) // expected-error{{only same-type and layout requirements are supported by '_specialize' attribute}}
+@specialized(where T: P) // expected-error{{only same-type are supported by 'specialized' attribute}}
 @_specialize(where T: Int) // expected-error{{type 'T' constrained to non-protocol, non-class type 'Int'}} expected-note {{use 'T == Int' to require 'T' to be 'Int'}}
 // expected-error@-1 {{too few generic parameters are specified in '_specialize' attribute (got 0, but expected 1)}}
 // expected-note@-2 {{missing constraint for 'T' in '_specialize' attribute}}
@@ -163,6 +179,9 @@ public func anotherFuncWithTwoGenericParameters<X: P, Y>(x: X, y: Y) {
 // expected-note@-2 {{missing constraint for 'T' in '_specialize' attribute}}
 @_specialize(where T: C1) // expected-error{{only same-type and layout requirements are supported by '_specialize' attribute}}
 @_specialize(where Int: P) // expected-error{{too few generic parameters are specified in '_specialize' attribute (got 0, but expected 1)}} expected-note{{missing constraint for 'T' in '_specialize' attribute}}
+@specialized(where T: Int) // expected-error{{type 'T' constrained to non-protocol, non-class type 'Int'}} expected-note {{use 'T == Int' to require 'T' to be 'Int'}}
+// expected-error@-1 {{too few generic parameters are specified in 'specialized' attribute (got 0, but expected 1)}}
+// expected-note@-2 {{missing constraint for 'T' in 'specialized' attribute}}
 func funcWithForbiddenSpecializeRequirement<T>(_ t: T) {
 }
 
@@ -230,10 +249,12 @@ public func copyValueAndReturn<S>(_ t: S, s: inout S) -> S where S: P{
 struct OuterStruct<S> {
   struct MyStruct<T> {
     @_specialize(where T == Int, U == Float) // expected-error{{too few generic parameters are specified in '_specialize' attribute (got 2, but expected 3)}} expected-note{{missing constraint for 'S' in '_specialize' attribute}}
+    @specialized(where T == Int, U == Float) // expected-error{{too few generic parameters are specified in 'specialized' attribute (got 2, but expected 3)}} expected-note{{missing constraint for 'S' in 'specialized' attribute}}
     public func foo<U>(u : U) {
     }
 
     @_specialize(where T == Int, U == Float, S == Int)
+    @specialized(where T == Int, U == Float, S == Int)
     public func bar<U>(u : U) {
     }
   }
@@ -308,6 +329,7 @@ extension Container {
 // E becomes concrete via the combination of 'S == Set<String>' and
 // 'E == S.Element'.
 @_specialize(where S == Set<String>)
+@specialized(where S == Set<String>)
 public func takesSequenceAndElement<S, E>(_: S, _: E)
   where S : Sequence, E == S.Element {}
 
@@ -350,6 +372,36 @@ public func foo<T : ProtocolWithDep>(_ t: T) where T.Element == ExpectedElement
 }
 
 @_specialize(where T == Conformer) // expected-error{{generic signature requires types 'Conformer.Element' (aka 'ConformerElement') and 'ExpectedElement' to be the same}}
+@specialized(where T == Conformer) // expected-error{{generic signature requires types 'Conformer.Element' (aka 'ConformerElement') and 'ExpectedElement' to be the same}}
 public func bar<T : ProtocolWithDep>(_ t: T) where T.Element == ExpectedElement {
   foo(t)
 }
+
+// CHECK: @specialized(where T == Int)
+@specialized(where T == Int)
+// CHECK: @specialized(where T == S<Int>)
+@specialized(where T == S<Int>)
+public func oneGenericParam2Good<T>(_ t: T) -> T {
+    return t
+}
+
+@specialized(where T == Int, U == Int) // expected-error{{cannot find type 'U' in scope}},
+@specialized(where T == T1) // expected-error{{cannot find type 'T1' in scope}},
+@specialized(where T : _Trivial) // expected-error{{layout constraints are only allowed inside '_specialize' attributes}} expected-error{{empty 'where' clause in 'specialized' attribute}}
+public func oneGenericParam2<T>(_ t: T) -> T {
+  return t
+}
+
+// CHECK: @specialized(where T == Int, U == Int)
+@specialized(where T == Int, U == Int)
+@specialized(where T == Int) // expected-error{{too few generic parameters are specified in 'specialized' attribute (got 1, but expected 2)}} expected-note{{missing constraint for 'U' in 'specialized' attribute}}
+public func twoGenericParams2<T, U>(_ t: T, u: U) -> (T, U) {
+  return (t, u)
+}
+
+@specialized(where T == Int) // expected-error{{trailing 'where' clause in 'specialized' attribute of non-generic function 'nonGenericParam2(x:)'}}
+func nonGenericParam2(x: Int) {}
+
+@_specialize(where T == Int)
+@_specialize(where T == Int)
+func genericParamDuplicate<T>(t: T) {}
diff --git a/test/attr/attr_static_exclusive_only.swift b/test/attr/attr_static_exclusive_only.swift
index 543b885b000b4..2f475a99ae4e6 100644
--- a/test/attr/attr_static_exclusive_only.swift
+++ b/test/attr/attr_static_exclusive_only.swift
@@ -2,7 +2,7 @@
 
 // REQUIRES: swift_feature_StaticExclusiveOnly
 
-@_staticExclusiveOnly // expected-error {{@_staticExclusiveOnly can only be applied to noncopyable types}}
+@_staticExclusiveOnly // expected-error {{'@_staticExclusiveOnly' can only be applied to noncopyable types}}
 struct A {}
 
 @_staticExclusiveOnly // OK
diff --git a/test/attr/attr_usableFromInline.swift b/test/attr/attr_usableFromInline.swift
index 10454ef8dd980..fe833477358ea 100644
--- a/test/attr/attr_usableFromInline.swift
+++ b/test/attr/attr_usableFromInline.swift
@@ -315,11 +315,11 @@ public struct TestGenericSubscripts {
   @usableFromInline package subscript<T>(where _: T) -> Int where T: PackageProtocol { return 0 } // expected-warning {{type referenced from a generic requirement of a '@usableFromInline' subscript should be '@usableFromInline' or public}}
 }
 
-@usableFromInline typealias TestGenericAlias<T: InternalProtocol> = T // expected-warning {{type referenced from a generic parameter of a '@usableFromInline' type alias should be '@usableFromInline' or public}}
-@usableFromInline typealias TestGenericAliasWhereClause<T> = T where T: InternalProtocol // expected-warning {{type referenced from a generic requirement of a '@usableFromInline' type alias should be '@usableFromInline' or public}}
+@usableFromInline typealias TestGenericAlias<T: InternalProtocol> = T // expected-warning {{type referenced from a generic parameter of a '@usableFromInline' generic type alias should be '@usableFromInline' or public}}
+@usableFromInline typealias TestGenericAliasWhereClause<T> = T where T: InternalProtocol // expected-warning {{type referenced from a generic requirement of a '@usableFromInline' generic type alias should be '@usableFromInline' or public}}
 
-@usableFromInline typealias PkgTestGenericAlias<T: PackageProtocol> = T // expected-warning {{type referenced from a generic parameter of a '@usableFromInline' type alias should be '@usableFromInline' or public}}
-@usableFromInline typealias PkgTestGenericAliasWhereClause<T> = T where T: PackageProtocol // expected-warning {{type referenced from a generic requirement of a '@usableFromInline' type alias should be '@usableFromInline' or public}}
+@usableFromInline typealias PkgTestGenericAlias<T: PackageProtocol> = T // expected-warning {{type referenced from a generic parameter of a '@usableFromInline' generic type alias should be '@usableFromInline' or public}}
+@usableFromInline typealias PkgTestGenericAliasWhereClause<T> = T where T: PackageProtocol // expected-warning {{type referenced from a generic requirement of a '@usableFromInline' generic type alias should be '@usableFromInline' or public}}
 
 @usableFromInline struct GenericStruct<T> {
   @usableFromInline struct Nested where T : InternalProtocol {}
diff --git a/test/attr/attr_usableFromInline_protocol_hole.swift b/test/attr/attr_usableFromInline_protocol_hole.swift
index 434f5351cde5c..a59d8639fd45f 100644
--- a/test/attr/attr_usableFromInline_protocol_hole.swift
+++ b/test/attr/attr_usableFromInline_protocol_hole.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -o %t/Lib.swiftmodule %S/Inputs/attr_usableFromInline_protocol_hole_helper.swift
-// RUN: %target-typecheck-verify-swift -I %t -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t -verify-ignore-unknown
 
 import Lib
 
diff --git a/test/attr/attr_weaklinked.swift b/test/attr/attr_weaklinked.swift
index a56dbf4bf8ecb..831afa281d32d 100644
--- a/test/attr/attr_weaklinked.swift
+++ b/test/attr/attr_weaklinked.swift
@@ -1,7 +1,6 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature ABIAttribute
+// RUN: %target-typecheck-verify-swift
 
 // UNSUPPORTED: OS=windows-msvc
-// REQUIRES: swift_feature_ABIAttribute
 
 @_weakLinked public func f() { }
 
diff --git a/test/attr/attributes.swift b/test/attr/attributes.swift
index 4e7de3b957de5..dd5f71f72d4f5 100644
--- a/test/attr/attributes.swift
+++ b/test/attr/attributes.swift
@@ -26,7 +26,7 @@ struct IBDesignableStructTy {}
 @IBDesignable // expected-error {{'@IBDesignable' attribute cannot be applied to this declaration}} {{1-15=}}
 protocol IBDesignableProtTy {}
 
-@IBDesignable // expected-error {{@IBDesignable can only be applied to classes and extensions of classes}} {{1-15=}}
+@IBDesignable // expected-error {{'@IBDesignable' can only be applied to classes and extensions of classes}} {{1-15=}}
 extension IBDesignableStructTy {}
 
 class IBDesignableClassExtensionTy {}
@@ -51,7 +51,7 @@ struct inspectableWithStruct {
   @GKInspectable var GKInspectableInStruct: Int // expected-error {{only class instance properties can be declared @GKInspectable}} {{3-18=}}
 }
 
-func foo(x: @convention(block) Int) {} // expected-error {{@convention attribute only applies to function types}}
+func foo(x: @convention(block) Int) {} // expected-error {{'@convention' only applies to function types}}
 func foo(x: @convention(block) (Int) -> Int) {}
 
 @_transparent
@@ -284,13 +284,13 @@ var globalUncheckedVar = 1
 var globalUnknownVar = 1
 
 struct ExclusivityAttrStruct {
-  @exclusivity(unchecked) // expected-error {{@exclusivity can only be used on class properties, static properties and global variables}}
+  @exclusivity(unchecked) // expected-error {{'@exclusivity' can only be used on class properties, static properties and global variables}}
   var instanceVar: Int = 27
 
   @exclusivity(unchecked) // ok
   static var staticVar: Int = 27
 
-  @exclusivity(unchecked) // expected-error {{@exclusivity can only be used on stored properties}}
+  @exclusivity(unchecked) // expected-error {{'@exclusivity' can only be used on stored properties}}
   static var staticComputedVar: Int { return 1 }
 }
 
@@ -301,7 +301,7 @@ class ExclusivityAttrClass {
   @exclusivity(unchecked) // ok
   static var staticVar: Int = 27
 
-  @exclusivity(unchecked) // expected-error {{@exclusivity can only be used on stored properties}}
+  @exclusivity(unchecked) // expected-error {{'@exclusivity' can only be used on stored properties}}
   static var staticComputedVar: Int { return 1 }
 }
 
@@ -331,10 +331,10 @@ func unownedOptionals(x: C) {
 
 // @_nonEphemeral attribute
 struct S1<T> {
-  func foo(@_nonEphemeral _ x: String) {} // expected-error {{@_nonEphemeral attribute only applies to pointer types}}
-  func bar(@_nonEphemeral _ x: T) {} // expected-error {{@_nonEphemeral attribute only applies to pointer types}}
+  func foo(@_nonEphemeral _ x: String) {} // expected-error {{'@_nonEphemeral' only applies to pointer types}}
+  func bar(@_nonEphemeral _ x: T) {} // expected-error {{'@_nonEphemeral' only applies to pointer types}}
 
-  func baz<U>(@_nonEphemeral _ x: U) {} // expected-error {{@_nonEphemeral attribute only applies to pointer types}}
+  func baz<U>(@_nonEphemeral _ x: U) {} // expected-error {{'@_nonEphemeral' only applies to pointer types}}
 
   func qux(@_nonEphemeral _ x: UnsafeMutableRawPointer) {}
   func quux(@_nonEphemeral _ x: UnsafeMutablePointer<Int>?) {}
diff --git a/test/attr/dynamicReplacement.swift b/test/attr/dynamicReplacement.swift
index 275432b23964a..ab048f2daba7b 100644
--- a/test/attr/dynamicReplacement.swift
+++ b/test/attr/dynamicReplacement.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend -emit-module -swift-version 5 -enable-implicit-dynamic %S/Inputs/dynamicReplacementA.swift -o %t -module-name A
 // RUN: %target-swift-frontend -emit-module -swift-version 5 -enable-implicit-dynamic -c %S/Inputs/dynamicReplacementB.swift -o %t -I %t -module-name B
 // RUN: %target-swift-frontend -emit-module -swift-version 5 -enable-implicit-dynamic -c %S/Inputs/dynamicReplacementC.swift -o %t -I %t -module-name C
-// RUN: %target-typecheck-verify-swift -swift-version 5 -enable-implicit-dynamic  -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 5 -enable-implicit-dynamic  -I %t
 import A
 import B
 import C
diff --git a/test/attr/execution_behavior_attrs.swift b/test/attr/execution_behavior_attrs.swift
new file mode 100644
index 0000000000000..fd0db27bf9986
--- /dev/null
+++ b/test/attr/execution_behavior_attrs.swift
@@ -0,0 +1,225 @@
+// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple
+
+// REQUIRES: concurrency
+
+// FIXME: Bad parser diagnostic on C++ side
+nonisolated(something) func invalidAttr() async {} // expected-error {{cannot find 'nonisolated' in scope}}
+// expected-error@-1 {{cannot find 'something' in scope}}
+// expected-error@-2 {{consecutive statements on a line must be separated by ';'}}
+
+@concurrent nonisolated(nonsending) func mutipleAttrs() async {}
+// expected-error@-1 {{global function 'mutipleAttrs()' has multiple actor-isolation attributes (@concurrent and 'nonisolated(nonsending)')}}
+
+do {
+  nonisolated(nonsending) struct S {}
+  // expected-error@-1 {{'nonisolated(nonsending)' is only applicable to asynchronous functions, initializers, subscripts and computed properties}}
+
+
+  func f(nonisolated(nonsending) param: Int) {}
+  // expected-error@-1 {{expected parameter name followed by ':'}}
+  // expected-error@-2 {{parameter may have at most one of the 'inout', 'borrowing', or 'consuming' specifiers}}
+}
+
+@concurrent func nonAsync1() {}
+// expected-error@-1 {{cannot use @concurrent on non-async global function 'nonAsync1()'}}
+
+nonisolated(nonsending) func nonAsync2() {}
+// expected-error@-1 {{cannot use 'nonisolated(nonsending)' on non-async global function 'nonAsync2()'}}
+
+@concurrent func testGlobal() async {} // Ok
+
+struct Test {
+  @concurrent init() {}
+  // expected-error@-1 {{cannot use @concurrent on non-async initializer 'init()'}}
+
+  @concurrent init(async: Void) async {}
+
+  @concurrent func member() {}
+  // expected-error@-1 {{cannot use @concurrent on non-async instance method 'member()'}}
+
+  @concurrent func member() async {} // Ok
+
+  @concurrent var syncP: Int {
+  // expected-error@-1 {{cannot use @concurrent on non-async property 'syncP'}}
+    get {}
+  }
+  @concurrent var asyncP: Int {
+    get async {}
+  }
+
+  // expected-error@+1 {{cannot use 'nonisolated(nonsending)' on non-async subscript 'subscript(sync:)'}}
+  nonisolated(nonsending) subscript(sync _: Int) -> Bool {
+    @concurrent get { false }
+    // expected-error@-1 {{@concurrent' attribute cannot be applied to this declaration}}
+    @concurrent set { }
+    // expected-error@-1 {{@concurrent' attribute cannot be applied to this declaration}}
+  }
+  nonisolated(nonsending) subscript(async _: Int) -> Bool {
+    get async {}
+  }
+
+  // FIXME: Incorrect quotes due to inconsistent DeclAttribute printing between modifiers and attributes
+  nonisolated(nonsending) var storedVar: Int
+  // expected-error@-1 {{''nonisolated(nonsending)'' must not be used on stored properties}}
+  nonisolated(nonsending) let storedLet: Int
+  // expected-error@-1 {{''nonisolated(nonsending)'' must not be used on stored properties}}
+}
+
+do {
+  class C {
+    nonisolated(nonsending) deinit {}
+    // expected-error@-1 {{'nonisolated(nonsending)' is only applicable to asynchronous functions, initializers, subscripts and computed properties}}
+  }
+}
+
+do {
+  nonisolated(nonsending) func local() async {} // Ok
+
+  protocol P {
+    nonisolated(nonsending) var syncP: Int { get }
+    // expected-error@-1 {{cannot use 'nonisolated(nonsending)' on non-async property 'syncP'}}
+
+    nonisolated(nonsending) var asyncP: Int { get async }
+  }
+}
+
+struct TestAttributeCollisions {
+  @concurrent nonisolated func testNonIsolated() async {}
+
+  @concurrent func test(arg: isolated MainActor) async {}
+  // expected-error@-1 {{cannot use @concurrent on instance method 'test(arg:)' because it has an isolated parameter: 'arg'}}
+  @concurrent subscript(test arg: isolated MainActor) -> Int {
+  // expected-error@-1 {{cannot use @concurrent on subscript 'subscript(test:)' because it has an isolated parameter: 'arg'}}
+    get async {}
+  }
+
+  @concurrent func testIsolationAny(arg: @isolated(any) () -> Void) async {}
+  @concurrent subscript(testIsolationAny arg: @isolated(any) () -> Void) -> Int {
+    get async {}
+  }
+
+  @MainActor @concurrent func testGlobalActor() async {}
+  // expected-error@-1 {{instance method 'testGlobalActor()' has multiple actor-isolation attributes (@MainActor and @concurrent)}}
+
+  nonisolated(nonsending) nonisolated func testNonIsolatedCaller() async {} // expected-error {{duplicate modifier}} expected-note {{modifier already specified here}}
+  @MainActor nonisolated(nonsending) func testGlobalActorCaller() async {}
+  // expected-error@-1 {{instance method 'testGlobalActorCaller()' has multiple actor-isolation attributes (@MainActor and 'nonisolated(nonsending)')}}
+  nonisolated(nonsending) func testCaller(arg: isolated MainActor) async {}
+  // expected-error@-1 {{cannot use 'nonisolated(nonsending)' on instance method 'testCaller(arg:)' because it has an isolated parameter: 'arg'}}
+  
+  @concurrent @Sendable func test(_: @Sendable () -> Void, _: sending Int) async {} // Ok
+  @Sendable nonisolated(nonsending) func testWithSendableCaller(_: @Sendable () -> Void, _: sending Int) async {} // Ok
+}
+
+@MainActor
+protocol P {
+  func test() async
+}
+
+struct InfersMainActor : P {
+  @concurrent func test() async {}
+}
+
+@MainActor
+struct IsolatedType {
+  @concurrent func test() async {}
+}
+
+// `@concurrent` on closures does not contribute to `async` inference.
+do {
+  _ = { @concurrent in }
+  // expected-error@-1:9 {{cannot use @concurrent on non-async closure}}{{none}}
+  _ = { @concurrent () -> Int in }
+  // expected-error@-1:9 {{cannot use @concurrent on non-async closure}}{{none}}
+  // Explicit effect precludes effects inference from the body.
+  _ = { @concurrent () throws in await awaitMe() }
+  // expected-error@-1:9 {{cannot use @concurrent on non-async closure}}{{none}}
+  // expected-error@-2:40 {{'async' call in a function that does not support concurrency}}{{none}}
+  _ = { @concurrent () async in }
+  _ = { @concurrent in await awaitMe() }
+
+  func awaitMe() async {}
+
+  do {
+    func foo(_: () -> Void) {}
+    func foo(_: () async -> Void) async {}
+
+    func sync() {
+      foo { @concurrent in }
+      // expected-error@-1:13 {{cannot use @concurrent on non-async closure}}{{none}}
+    }
+    // expected-note@+1:10 {{add 'async' to function 'sync2()' to make it asynchronous}}{{17-17= async}}
+    func sync2() {
+      foo { @concurrent in await awaitMe() }
+      // expected-error@-1:7 {{'async' call in a function that does not support concurrency}}{{none}}
+    }
+    func async() async {
+      // Even though the context is async, the sync overload is favored because
+      // the closure is sync, so the error is expected.
+      foo { @concurrent in }
+      // expected-error@-1:13 {{cannot use @concurrent on non-async closure}}{{none}}
+
+      foo { @concurrent in await awaitMe() }
+      // expected-error@-1:7 {{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
+      // expected-note@-2:7 {{call is 'async'}}{{none}}
+    }
+  }
+
+  do {
+    func foo(_: (Int) async -> Void) {}
+    func foo(_: (Int) -> Void) async {}
+
+    func sync() {
+      // OK, sync overload picked.
+      foo { @concurrent _ in }
+    }
+    func async() async {
+      foo { @concurrent _ in }
+      // expected-error@-1:13 {{cannot use @concurrent on non-async closure}}{{none}}
+      // expected-error@-2:7 {{expression is 'async' but is not marked with 'await'}}{{7-7=await }}
+      // expected-note@-3:7 {{call is 'async'}}{{none}}
+    }
+  }
+
+  do {
+    func foo<T>(_: T) {}
+
+    foo({@concurrent in })
+    // expected-error@-1:10 {{cannot use @concurrent on non-async closure}}{{none}}
+  }
+}
+
+_ = { @MainActor @concurrent in
+  // expected-error@-1 {{cannot use @concurrent because function type is isolated to a global actor 'MainActor'}}
+}
+
+// Make sure that explicit use of `@concurrent` doesn't interfere with inference of `throws` from the body.
+do {
+    func acceptsThrowing(_ body: () async throws -> Void) async {
+    }
+
+  struct Invocation {
+    func throwingFn() async throws {
+    }
+  }
+
+  func test(invocation: Invocation) async {
+    await acceptsThrowing({ @concurrent in try await invocation.throwingFn() }) // Ok
+    await acceptsThrowing({ @concurrent [invocation] in try await invocation.throwingFn() }) // Ok
+
+    await acceptsThrowing({ @concurrent in // Ok
+      _ = 42
+      try await invocation.throwingFn()
+    })
+  }
+}
+
+do {
+  nonisolated(nonsending)
+  func testOnDecl(_: @isolated(any) () -> Void) async {} // Ok
+
+  func testOnType1(_: nonisolated(nonsending) @isolated(any) () async -> Void) {}
+  // expected-error@-1 {{cannot use 'nonisolated(nonsending)' together with '@isolated(any)'}}
+  func testOnType2(_: @concurrent @isolated(any) () async -> Void) {}
+  // expected-error@-1 {{cannot use '@concurrent' together with '@isolated(any)'}}
+}
diff --git a/test/attr/feature_requirement.swift b/test/attr/feature_requirement.swift
index f568a707b91ad..31612d2850c7c 100644
--- a/test/attr/feature_requirement.swift
+++ b/test/attr/feature_requirement.swift
@@ -1,16 +1,13 @@
 // RUN: %target-typecheck-verify-swift -parse-as-library -disable-experimental-parser-round-trip -verify-additional-prefix disabled-
-// RUN: %target-typecheck-verify-swift -parse-as-library -verify-additional-prefix enabled- -enable-experimental-feature ABIAttribute
+// RUN: %target-typecheck-verify-swift -parse-as-library -verify-additional-prefix enabled-
 
 // REQUIRES: asserts
 
+// NOTE: There are currently no experimental features that need code completion
+// testing, but this test file is being left in place for when it's needed
+// again. At that time, please remove the ABIAttribute tests.
+// REQUIRES: new_use_case
+
 // This test checks whether DECL_ATTR_FEATURE_REQUIREMENT is being applied correctly.
 // It is expected to need occasional edits as experimental features are stabilized.
 
-@abi(func fn())
-func fn() {}  // expected-disabled-error@-1 {{'abi' attribute is only valid when experimental feature ABIAttribute is enabled}}
-
-#if hasAttribute(abi)
-  #error("does have @abi")  // expected-enabled-error {{does have @abi}}
-#else
-  #error("doesn't have @abi")  // expected-disabled-error {{doesn't have @abi}}
-#endif
diff --git a/test/attr/global_actor.swift b/test/attr/global_actor.swift
index da21d2f257d8a..51088ed816952 100644
--- a/test/attr/global_actor.swift
+++ b/test/attr/global_actor.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify %s  -disable-availability-checking -package-name myPkg
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %s  -disable-availability-checking -package-name myPkg
 // REQUIRES: concurrency
 
 actor SomeActor { }
@@ -98,7 +98,7 @@ struct Container {
 // Redundant attributes
 // -----------------------------------------------------------------------
 extension SomeActor {
-  @GA1 nonisolated func conflict1() { } // expected-warning {{instance method 'conflict1()' has multiple actor-isolation attributes (@GA1 and 'nonisolated')}}
+  @GA1 nonisolated func conflict1() { } // expected-error {{instance method 'conflict1()' has multiple actor-isolation attributes (@GA1 and 'nonisolated')}}
 }
 
 
diff --git a/test/attr/lexical.swift b/test/attr/lexical.swift
index 7794503984ec7..7f5314accc402 100644
--- a/test/attr/lexical.swift
+++ b/test/attr/lexical.swift
@@ -9,7 +9,7 @@ enum E {}
 @_eagerMove // expected-error {{'@_eagerMove' attribute cannot be applied to this declaration}}
 typealias EagerTuple = (C, C)
 
-func foo(@_noEagerMove @_eagerMove _ e: E) {} // expected-error {{@_eagerMove and @_noEagerMove attributes are alternate styles of lifetimes and can't be combined}}
+func foo(@_noEagerMove @_eagerMove _ e: E) {} // expected-error {{'@_eagerMove' and '@_noEagerMove' are alternate styles of lifetimes and can't be combined}}
 
 func bar(@_noEagerMove _ s: S) {} // okay
 
@@ -37,7 +37,7 @@ struct S2 {
 func foo() {
   @_noEagerMove let s1 = S()
   @_eagerMove var s2 = S()
-  @_noEagerMove @_eagerMove let s3 = S() // expected-error {{@_eagerMove and @_noEagerMove attributes are alternate styles of lifetimes and can't be combined}}
+  @_noEagerMove @_eagerMove let s3 = S() // expected-error {{'@_eagerMove' and '@_noEagerMove' are alternate styles of lifetimes and can't be combined}}
   _ = s1
   s2 = S()
   _ = s2
@@ -46,13 +46,13 @@ func foo() {
 
 struct MoveOnly : ~Copyable {}
 
-@_eagerMove struct MoveOnlyEagerly : ~Copyable {} // expected-error {{@_eagerMove cannot be applied to NonCopyable types}}
+@_eagerMove struct MoveOnlyEagerly : ~Copyable {} // expected-error {{'@_eagerMove' cannot be applied to NonCopyable types}}
 
-func zoo(@_eagerMove _ : consuming MoveOnly) {} // expected-error {{@_eagerMove cannot be applied to NonCopyable types}}
+func zoo(@_eagerMove _ : consuming MoveOnly) {} // expected-error {{'@_eagerMove' cannot be applied to NonCopyable types}}
 
 func zooo(@_noEagerMove  _ : consuming C) {} // ok, only way to spell this behavior
 
 extension MoveOnly {
-  @_eagerMove // expected-error {{@_eagerMove cannot be applied to NonCopyable types}}
+  @_eagerMove // expected-error {{'@_eagerMove' cannot be applied to NonCopyable types}}
   func zoo() {}
 }
diff --git a/test/attr/open.swift b/test/attr/open.swift
index 9a8fb1172f708..2cb96960770e4 100644
--- a/test/attr/open.swift
+++ b/test/attr/open.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -emit-module %S/Inputs/OpenHelpers.swift -o %t/OpenHelpers.swiftmodule
-// RUN: %target-typecheck-verify-swift -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t
 
 import OpenHelpers
 
diff --git a/test/attr/require_explicit_availability_macos.swift b/test/attr/require_explicit_availability_macos.swift
index 8cb178c944fcb..dd1991bd08861 100644
--- a/test/attr/require_explicit_availability_macos.swift
+++ b/test/attr/require_explicit_availability_macos.swift
@@ -144,6 +144,8 @@ private class PrivateClass { }
 
 extension PrivateClass { }
 
+extension PrivateClass : P { }
+
 @available(macOS 10.1, *)
 public protocol PublicProtocol { }
 
@@ -162,6 +164,8 @@ extension spiStruct {
   public func spiExtensionMethod() {}
 }
 
+extension spiStruct : P { }
+
 public var publicVar = S() // expected-warning {{public declarations should have an availability attribute with an introduction version}} {{1-1=@available(macOS 10.10, *)\n}}
 
 @available(macOS 10.10, *)
@@ -248,7 +252,7 @@ extension SomeClass { // expected-warning {{public declarations should have an a
 public struct StructWithImplicitMembers { }
 
 extension StructWithImplicitMembers: Hashable { }
-// expected-note @-1 {{add @available attribute to enclosing extension}}
+// expected-note @-1 {{add '@available' attribute to enclosing extension}}
 // expected-warning @-2 {{public declarations should have an availability attribute with an introduction version}}
 // expected-error @-3 {{'StructWithImplicitMembers' is only available in macOS 10.15 or newer}}
 
diff --git a/test/attr/spi_available.swift b/test/attr/spi_available.swift
index 21604297014f7..55413f7a7eb51 100644
--- a/test/attr/spi_available.swift
+++ b/test/attr/spi_available.swift
@@ -1,16 +1,16 @@
 // RUN: %target-typecheck-verify-swift
 
 @_spi_available(*, deprecated, renamed: "another") // expected-error {{SPI available only supports introducing version on specific platform}}
-public class SPIClass1 {} // expected-warning {{symbols that are @_spi_available on all platforms should use @_spi instead}}
+public class SPIClass1 {} // expected-warning {{symbols that are '@_spi_available' on all platforms should use '@_spi' instead}}
 
 @_spi_available(*, unavailable) // expected-error {{SPI available only supports introducing version on specific platform}}
-public class SPIClass2 {} // expected-warning {{symbols that are @_spi_available on all platforms should use @_spi instead}}
+public class SPIClass2 {} // expected-warning {{symbols that are '@_spi_available' on all platforms should use '@_spi' instead}}
 
 @_spi_available(AlienPlatform 5.2, *) // expected-warning {{unrecognized platform name 'AlienPlatform'}}
 public class SPIClass3 {}
 
 @_spi_available(macOS 10.4, *)
-public class SPIClass4 {} // expected-warning {{symbols that are @_spi_available on all platforms should use @_spi instead}}
+public class SPIClass4 {} // expected-warning {{symbols that are '@_spi_available' on all platforms should use '@_spi' instead}}
 
 @_spi_available(macos 10.15, *) // expected-warning {{unrecognized platform name 'macos'; did you mean 'macOS'?}} {{17-22=macOS}}
 public class SPIClass5 {}
diff --git a/test/attr/typeEraser.swift b/test/attr/typeEraser.swift
index 7ac2e78247779..f95050285429b 100644
--- a/test/attr/typeEraser.swift
+++ b/test/attr/typeEraser.swift
@@ -29,11 +29,11 @@ protocol Collection {
 @_typeEraser // expected-error {{expected '(' in '_typeEraser' attribute}}
 protocol A1 {}
 
-@_typeEraser() // expected-error {{expected a type name in @_typeEraser()}}
+@_typeEraser() // expected-error {{expected a type name in '@_typeEraser()'}}
 protocol A2 {}
 
 @_typeEraser(AnyP // expected-note {{to match this opening '('}}
-protocol A3 {} // expected-error {{expected ')' after type name for @_typeEraser}}
+protocol A3 {} // expected-error {{expected ')' after type name for '@_typeEraser'}}
 
 @_typeEraser(AnyP) // expected-error {{@_typeEraser may only be used on 'protocol' declarations}}
 func notAProtocol() {}
@@ -50,7 +50,7 @@ protocol InvalidTypeEraser {}
 @_typeEraser(InvalidTypeEraser) // expected-error {{type eraser must be a class, struct, or enum}}
 protocol B3 {}
 
-class Generic<Param>: B5 { // expected-note {{generic type 'Generic' declared here}}
+class Generic<Param>: B5 { // expected-note {{generic class 'Generic' declared here}}
   init<T: B5>(erasing t: T) {}
 }
 @_typeEraser(Generic) // expected-error {{reference to generic type 'Generic' requires arguments in <...>}}
diff --git a/test/cmake/modules/SwiftTestUtils.cmake b/test/cmake/modules/SwiftTestUtils.cmake
index 746c25d416d6a..1bdbab8cc6185 100644
--- a/test/cmake/modules/SwiftTestUtils.cmake
+++ b/test/cmake/modules/SwiftTestUtils.cmake
@@ -30,7 +30,7 @@ function(get_swift_test_versioned_target_triple variant_triple_out_var sdk arch
     # Use the macCatalyst target triple and compiler resources for the iOS-like build flavor.
     set(variant_triple "${arch}-apple-ios13.1-macabi")
   else()
-    get_versioned_target_triple(variant_triple ${sdk} ${arch} "${SWIFT_SDK_${sdk}_DEPLOYMENT_VERSION}")
+    get_versioned_target_triple(variant_triple ${sdk} ${arch} "${SWIFT_SDK_${sdk}_TEST_DEPLOYMENT_VERSION}")
   endif()
 
   set(${variant_triple_out_var} "${variant_triple}" PARENT_SCOPE)
diff --git a/test/decl/circularity.swift b/test/decl/circularity.swift
index 5b6ff3ad895c3..a30289c162116 100644
--- a/test/decl/circularity.swift
+++ b/test/decl/circularity.swift
@@ -68,12 +68,11 @@ class C1 {
     func run(a: Int) {}
 }
 
-class C2: C1, P {
-    // expected-note@-1 2{{through reference here}}
+class C2: C1, P { // expected-note@:7 {{through reference here}}
     override func run(a: A) {}
-    // expected-error@-1 {{circular reference}}
-    // expected-note@-2 {{while resolving type 'A'}}
-    // expected-note@-3 2{{through reference here}}
+    // expected-error@-1:19 {{circular reference}}
+    // expected-note@-2:26 {{while resolving type 'A'}}
+    // expected-note@-3:23 {{through reference here}}
 }
 
 // Another crash to the above
@@ -84,12 +83,12 @@ open class G1<A> {
 class C3: G1<A>, P {
     // expected-error@-1 {{type 'C3' does not conform to protocol 'P'}}
     // expected-error@-2 {{cannot find type 'A' in scope}}
-    // expected-note@-3 2{{through reference here}}
+    // expected-note@-3:7 {{through reference here}}
     // expected-note@-4 {{add stubs for conformance}}
     override func run(a: A) {}
-    // expected-error@-1 {{circular reference}}
-    // expected-note@-2 2 {{through reference here}}
-    // expected-note@-3 {{while resolving type 'A'}}
+    // expected-error@-1:19 {{circular reference}}
+    // expected-note@-2:26 {{while resolving type 'A'}}
+    // expected-note@-3:23 {{through reference here}}
 }
 
 // Another case that triggers circular override checking.
@@ -99,21 +98,21 @@ protocol P1 {
 }
 
 class C4 {
-  required init(x: Int) {}
+  required init(x: Int) {} // expected-note {{'required' initializer is declared in superclass here}}
 }
 
-class D4 : C4, P1 { // expected-note 4 {{through reference here}}
-  required init(x: X) { // expected-error {{circular reference}}
-    // expected-note@-1 {{while resolving type 'X'}}
-    // expected-note@-2 2{{through reference here}}
+class D4 : C4, P1 { // expected-note@:7 {{through reference here}}
+  required init(x: X) { // expected-error@:12 {{circular reference}}
+    // expected-note@-1:20 {{while resolving type 'X'}}
+    // expected-note@-2:17 {{through reference here}}
     super.init(x: x)
   }
-}
+} // expected-error {{'required' initializer 'init(x:)' must be provided by subclass of 'C4'}}
 
 // https://github.com/apple/swift/issues/54662
 // N.B. This used to compile in 5.1.
 protocol P_54662 { }
 class C_54662 { // expected-note {{through reference here}}
-    typealias Nest = P_54662 // expected-error {{circular reference}} expected-note {{through reference here}}
+    typealias Nest = P_54662 // expected-error {{circular reference}}
 }
 extension C_54662: C_54662.Nest { }
diff --git a/test/decl/class/actor/basic.swift b/test/decl/class/actor/basic.swift
index 72c784864848a..23749ee114d15 100644
--- a/test/decl/class/actor/basic.swift
+++ b/test/decl/class/actor/basic.swift
@@ -7,7 +7,7 @@ actor MyActor { }
 class MyActorSubclass1: MyActor { }
 // expected-error@-1{{actor types do not support inheritance}}
 // expected-error@-2{{type 'MyActorSubclass1' cannot conform to the 'Actor' protocol}}
-// expected-warning@-3 {{non-final class 'MyActorSubclass1' cannot conform to 'Sendable'; use '@unchecked Sendable'; this is an error in the Swift 6 language mode}}
+// expected-warning@-3 {{non-final class 'MyActorSubclass1' cannot conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode}}
 
 actor MyActorSubclass2: MyActor { } // expected-error{{actor types do not support inheritance}}
 
diff --git a/test/decl/class/actor/global_actor_conformance.swift b/test/decl/class/actor/global_actor_conformance.swift
index edb828b5342da..6016b8a7ad6a9 100644
--- a/test/decl/class/actor/global_actor_conformance.swift
+++ b/test/decl/class/actor/global_actor_conformance.swift
@@ -32,6 +32,7 @@ protocol P2 {
 // expected-warning@+1{{conformance of 'C1' to protocol 'P1' crosses into global actor 'GlobalActor'-isolated code and can cause data races}}
 class C1 : P1, P2 {
   // expected-note@-1{{turn data races into runtime errors with '@preconcurrency'}}
+  // expected-note@-2{{isolate this conformance to the global actor 'GlobalActor' with '@GlobalActor'}}
 
   typealias Assoc = String
 
@@ -57,6 +58,7 @@ protocol NonIsolatedRequirement {
 extension OnMain: NonIsolatedRequirement {
   // expected-note@-1{{turn data races into runtime errors with '@preconcurrency'}}
   // expected-note@-2{{mark all declarations used in the conformance 'nonisolated'}}
+  // expected-note@-3{{isolate this conformance to the main actor with '@MainActor'}}
   // expected-note@+1 {{main actor-isolated instance method 'requirement()' cannot satisfy nonisolated requirement}}
   func requirement() {}
 }
diff --git a/test/decl/class/circular_inheritance.swift b/test/decl/class/circular_inheritance.swift
index 8d3611558082f..7ad002e54a409 100644
--- a/test/decl/class/circular_inheritance.swift
+++ b/test/decl/class/circular_inheritance.swift
@@ -1,18 +1,18 @@
 // RUN: %target-typecheck-verify-swift
 
-class Left // expected-error {{'Left' inherits from itself}} expected-note {{through reference here}}
+class Left // expected-error {{'Left' inherits from itself}}
     : Right.Hand { // expected-note {{through reference here}}
   class Hand {}
 }
 
-class Right // expected-note {{through reference here}} expected-note{{class 'Right' declared here}}
+class Right // expected-note {{through class 'Right' declared here}}
   : Left.Hand { // expected-note {{through reference here}}
   class Hand {}
 }
 
 class C : B { } // expected-error{{'C' inherits from itself}}
-class B : A { } // expected-note{{class 'B' declared here}}
-class A : C { } // expected-note{{class 'A' declared here}}
+class B : A { } // expected-note{{through class 'B' declared here}}
+class A : C { } // expected-note{{through class 'A' declared here}}
 
 class TrivialCycle : TrivialCycle {} // expected-error{{'TrivialCycle' inherits from itself}}
 protocol P : P {} // expected-error {{protocol 'P' refines itself}}
@@ -26,13 +26,13 @@ class Outer {
   class Inner : Outer {}
 }
 
-class Outer2 // expected-error {{'Outer2' inherits from itself}} expected-note  {{through reference here}}
+class Outer2 // expected-error {{'Outer2' inherits from itself}}
     : Outer2.Inner { // expected-note {{through reference here}}
 
   class Inner {}
 }
 
-class Outer3 // expected-error {{'Outer3' inherits from itself}} expected-note  {{through reference here}}
+class Outer3 // expected-error {{'Outer3' inherits from itself}}
     : Outer3.Inner<Int> { // expected-note {{through reference here}}
   class Inner<T> {}
 }
diff --git a/test/decl/class/circular_inheritance_2.swift b/test/decl/class/circular_inheritance_2.swift
index d1f7bb3e54732..7f977a6a1cb1d 100644
--- a/test/decl/class/circular_inheritance_2.swift
+++ b/test/decl/class/circular_inheritance_2.swift
@@ -4,5 +4,6 @@
 class Foo {}
 class Bar: Bar {} // expected-error{{'Bar' inherits from itself}}
 func foo(_ o: AnyObject) -> Foo? {
-    return o as? Bar // expected-error{{cannot convert return expression of type 'Bar?' to return type 'Foo?'}}
+  return o as? Bar // expected-error{{cannot convert return expression of type 'Bar?' to return type 'Foo?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('Bar' and 'Foo') are expected to be equal}}
 }
diff --git a/test/decl/class/inheritance_across_modules.swift b/test/decl/class/inheritance_across_modules.swift
index 360706abbb974..cfc6b708c7ba0 100644
--- a/test/decl/class/inheritance_across_modules.swift
+++ b/test/decl/class/inheritance_across_modules.swift
@@ -3,7 +3,7 @@
 
 // RUN: %target-swift-frontend -emit-module-path %t/MyModule.swiftmodule %t/Inputs/MyModule.swift
 
-// RUN: %target-swift-frontend -typecheck -verify -I %t %t/test.swift
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t %t/test.swift
 
 //--- Inputs/MyModule.swift
 open class MySuperclassA {
diff --git a/test/decl/class/override.swift b/test/decl/class/override.swift
index e1b358e9007f2..634610818ba6d 100644
--- a/test/decl/class/override.swift
+++ b/test/decl/class/override.swift
@@ -236,7 +236,7 @@ class IUOTestSubclassOkay : IUOTestBaseClass {
   override func oneC(_ x: AnyObject) {}
 }
 
-class GenericBase<T> { // expected-note{{generic type 'GenericBase' declared here}}
+class GenericBase<T> { // expected-note{{generic class 'GenericBase' declared here}}
   var values: Int { 0 } // expected-note{{attempt to override property here}}
 }
 
diff --git a/test/decl/enum/bool_raw_value.swift b/test/decl/enum/bool_raw_value.swift
index 6e6166e7d397b..f8df772e65c28 100644
--- a/test/decl/enum/bool_raw_value.swift
+++ b/test/decl/enum/bool_raw_value.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 extension Bool: @retroactive ExpressibleByIntegerLiteral {
 	public init(integerLiteral value: Int) {
 		self = value != 0
diff --git a/test/decl/enum/invalid_raw_value.swift b/test/decl/enum/invalid_raw_value.swift
new file mode 100644
index 0000000000000..31ef46e50a5c7
--- /dev/null
+++ b/test/decl/enum/invalid_raw_value.swift
@@ -0,0 +1,7 @@
+// RUN: %target-typecheck-verify-swift
+
+_ = a.init
+_ = b.init
+
+enum a : Int { case x = #/ /# }  // expected-error {{raw value for enum case must be a literal}}
+enum b : String { case x = #file }  // expected-error {{raw value for enum case must be a literal}}
diff --git a/test/decl/ext/Inputs/c_decls.h b/test/decl/ext/Inputs/c_decls.h
new file mode 100644
index 0000000000000..9f9526fec249c
--- /dev/null
+++ b/test/decl/ext/Inputs/c_decls.h
@@ -0,0 +1 @@
+double c_function_returns_double(void);
diff --git a/test/decl/ext/Inputs/module.modulemap b/test/decl/ext/Inputs/module.modulemap
new file mode 100644
index 0000000000000..796a273ec3dd7
--- /dev/null
+++ b/test/decl/ext/Inputs/module.modulemap
@@ -0,0 +1,3 @@
+module ToBeImplemented {
+  header "c_decls.h"
+}
diff --git a/test/decl/ext/Inputs/objc_implementation.h b/test/decl/ext/Inputs/objc_implementation.h
index 62241c1f8d94e..7b4920f20a34e 100644
--- a/test/decl/ext/Inputs/objc_implementation.h
+++ b/test/decl/ext/Inputs/objc_implementation.h
@@ -53,6 +53,7 @@
 @property (readonly) int readonlyPropertyFromHeader4;
 @property (readonly) int readonlyPropertyFromHeader5;
 @property (readonly) int readonlyPropertyFromHeader6;
+@property (readonly) int readonlyPropertyFromHeader7;
 
 + (void)classMethod1:(int)param;
 + (void)classMethod2:(int)param;
@@ -84,6 +85,10 @@
 @property int categoryPropertyFromHeader2;
 @property int categoryPropertyFromHeader3;
 @property int categoryPropertyFromHeader4;
+@property int categoryPropertyFromHeader5;
+
+@property (readonly) int categoryReadonlyPropertyFromHeader1;
+
 
 @end
 
@@ -118,6 +123,7 @@
 - (void)doSomethingAsynchronousWithCompletionHandler:(void (^ _Nonnull)(id _Nullable result, NSError * _Nullable error))completionHandler;
 - (void)doSomethingElseAsynchronousWithCompletionHandler:(void (^ _Nullable)(id _Nonnull result))completionHandler;
 - (void)doSomethingFunAndAsynchronousWithCompletionHandler:(void (^ _Nonnull)(id _Nullable result, NSError * _Nullable error))completionHandler;
+- (void)doSomethingMissingAndAsynchronousWithCompletionHandler:(void (^ _Nonnull)(id _Nullable result, NSError * _Nullable error))completionHandler;
 
 - (void)doSomethingOverloadedWithCompletionHandler:(void (^ _Nonnull)())completionHandler;
 - (void)doSomethingOverloaded __attribute__((__swift_attr__("@_unavailableFromAsync(message: \"Use async doSomethingOverloaded instead.\")")));
@@ -225,6 +231,8 @@
 void CImplFunc1(int param);
 void CImplFunc2(int param);
 
+void CImplFuncRenamed_C(int param) __attribute__((swift_name("CImplFuncRenamed_Swift(arg:)")));
+
 void CImplFuncMismatch1(int param);
 void CImplFuncMismatch2(int param);
 
diff --git a/test/decl/ext/cdecl_official_implementation.swift b/test/decl/ext/cdecl_official_implementation.swift
new file mode 100644
index 0000000000000..87ddea64ccd72
--- /dev/null
+++ b/test/decl/ext/cdecl_official_implementation.swift
@@ -0,0 +1,88 @@
+// RUN: %target-typecheck-verify-swift -target %target-stable-abi-triple \
+// RUN:   -import-bridging-header %S/Inputs/objc_implementation.h \
+// RUN:   -I %S/Inputs \
+// RUN:   -disable-objc-interop \
+// RUN:   -enable-experimental-feature CImplementation \
+// RUN:   -enable-experimental-feature CDecl
+
+// REQUIRES: swift_feature_CImplementation
+// REQUIRES: swift_feature_CDecl
+
+import ToBeImplemented
+
+@implementation @c
+func c_function_returns_double() -> Double { 0 }
+
+@implementation @c
+func CImplFunc1(_: Int32) {
+  // OK
+}
+
+@implementation @c(CImplFuncRenamed_C)
+func CImplFuncRenamed_Swift(arg: CInt) {
+  // OK
+}
+
+@implementation(BadCategory) @c
+func CImplFunc2(_: Int32) {
+  // expected-error@-2 {{global function 'CImplFunc2' does not belong to an Objective-C category; remove the category name from this attribute}} {{16-29=}}
+}
+
+@implementation @c
+func CImplFuncMissing(_: Int32) {
+  // expected-error@-2 {{could not find imported function 'CImplFuncMissing' matching global function 'CImplFuncMissing'; make sure you import the module or header that declares it}}
+}
+
+@implementation @c
+func CImplFuncMismatch1(_: Float) {
+  // expected-error@-1 {{global function 'CImplFuncMismatch1' of type '(Float) -> ()' does not match type '(Int32) -> Void' declared by the header}}
+}
+
+@implementation @c
+func CImplFuncMismatch2(_: Int32) -> Float {
+  // expected-error@-1 {{global function 'CImplFuncMismatch2' of type '(Int32) -> Float' does not match type '(Int32) -> Void' declared by the header}}
+}
+
+@implementation @c(CImplFuncNameMismatch1)
+func mismatchedName1(_: Int32) {
+  // expected-error@-2 {{could not find imported function 'CImplFuncNameMismatch1' matching global function 'mismatchedName1'; make sure you import the module or header that declares it}}
+  // FIXME: Improve diagnostic for a partial match.
+}
+
+@implementation @c(mismatchedName2)
+func CImplFuncNameMismatch2(_: Int32) {
+  // expected-error@-2 {{could not find imported function 'mismatchedName2' matching global function 'CImplFuncNameMismatch2'; make sure you import the module or header that declares it}}
+  // FIXME: Improve diagnostic for a partial match.
+}
+
+//
+// TODO: @c for global functions imported as computed vars
+//
+var cImplComputedGlobal1: Int32 {
+  @implementation @c(CImplGetComputedGlobal1)
+  get {
+    // FIXME: Lookup for vars isn't working yet
+    // expected-error@-3 {{could not find imported function 'CImplGetComputedGlobal1' matching getter for var 'cImplComputedGlobal1'; make sure you import the module or header that declares it}}
+    return 0
+  }
+
+  @implementation @c(CImplSetComputedGlobal1)
+  set {
+    // FIXME: Lookup for vars isn't working yet
+    // expected-error@-3 {{could not find imported function 'CImplSetComputedGlobal1' matching setter for var 'cImplComputedGlobal1'; make sure you import the module or header that declares it}}
+    print(newValue)
+  }
+}
+
+//
+// TODO: @c for import-as-member functions
+//
+extension CImplStruct {
+  @implementation @c(CImplStructStaticFunc1)
+  static func staticFunc1(_: Int32) {
+    // FIXME: Add underlying support for this
+    // expected-error@-3 {{@c can only be applied to global functions}}
+    // FIXME: Lookup in an enclosing type is not working yet
+    // expected-error@-5 {{could not find imported function 'CImplStructStaticFunc1' matching static method 'staticFunc1'; make sure you import the module or header that declares it}}
+  }
+}
diff --git a/test/decl/ext/extension-generic-objc-protocol.swift b/test/decl/ext/extension-generic-objc-protocol.swift
index bb5d9ae71d1ac..4b5b500aae1b7 100644
--- a/test/decl/ext/extension-generic-objc-protocol.swift
+++ b/test/decl/ext/extension-generic-objc-protocol.swift
@@ -10,7 +10,7 @@ import Foundation
 
 public class C1<T> {}
 extension C1: P {}
-// expected-error@-1 {{conformance of generic class 'C1<T>' to @objc protocol 'P' cannot be in an extension}}
+// expected-error@-1 {{conformance of generic class 'C1<T>' to '@objc' protocol 'P' cannot be in an extension}}
 
 public class C2<T> {}
 public class C3 : C2<Int> {}
@@ -22,7 +22,7 @@ class Outer<T> {
 }
 
 extension Outer.Inner: P {}
-// expected-error@-1 {{conformance of class from generic context 'Outer<T>.Inner' to @objc protocol 'P' cannot be in an extension}}
+// expected-error@-1 {{conformance of class from generic context 'Outer<T>.Inner' to '@objc' protocol 'P' cannot be in an extension}}
 
 class SubInner: Outer<Int>.Inner2 {}
 
diff --git a/test/decl/ext/extensions.swift b/test/decl/ext/extensions.swift
index 11d856702e22b..3835fe1bad9cc 100644
--- a/test/decl/ext/extensions.swift
+++ b/test/decl/ext/extensions.swift
@@ -402,3 +402,5 @@ extension BitwiseCopyable {} // expected-error {{cannot extend protocol 'Bitwise
 
 @_marker protocol MyMarkerProto {}
 extension MyMarkerProto {} // OK
+
+extension _ {} // expected-error {{cannot extend a type that contains placeholders}}
diff --git a/test/decl/ext/generic.swift b/test/decl/ext/generic.swift
index 86e7e9f50da8c..2191b6d98f1e0 100644
--- a/test/decl/ext/generic.swift
+++ b/test/decl/ext/generic.swift
@@ -230,3 +230,24 @@ extension (NewGeneric) {
     return NewGeneric()
   }
 }
+
+protocol P7 {}
+extension Float: P7 {}
+
+protocol Q1 {
+  associatedtype X
+  func foo(_ x: X)
+}
+struct S7<T: P7>: Q1 {
+  func foo(_ x: T) {}
+}
+
+// Make sure we reject these extensions.
+extension S7<Int> {} // expected-error {{type 'Int' does not conform to protocol 'P7'}}
+extension [S7<Int>] {} // expected-error {{type 'Int' does not conform to protocol 'P7'}}
+extension Array<S7<Int>> {} // expected-error {{type 'Int' does not conform to protocol 'P7'}}
+extension S7<Int>? {} // expected-error {{type 'Int' does not conform to protocol 'P7'}}
+extension S7<Int>.X {} // expected-error {{type 'Int' does not conform to protocol 'P7'}}
+extension S7<Float>.X {} // expected-error {{extension of type 'S7<Float>.X' (aka 'Float') must be declared as an extension of 'Float'}}
+// expected-note@-1 {{did you mean to extend 'Float' instead?}}
+extension S7<T> {} // expected-error {{cannot find type 'T' in scope}}
diff --git a/test/decl/ext/objc_implementation.swift b/test/decl/ext/objc_implementation.swift
index 8fa6d92f09884..e8a825db6e616 100644
--- a/test/decl/ext/objc_implementation.swift
+++ b/test/decl/ext/objc_implementation.swift
@@ -1,20 +1,23 @@
-// RUN: %target-typecheck-verify-swift -import-objc-header %S/Inputs/objc_implementation.h -enable-experimental-feature ObjCImplementation -enable-experimental-feature CImplementation -target %target-stable-abi-triple
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -import-objc-header %S/Inputs/objc_implementation.h -enable-experimental-feature ObjCImplementation -enable-experimental-feature CImplementation -target %target-stable-abi-triple
 // REQUIRES: objc_interop
 // REQUIRES: swift_feature_CImplementation
 // REQUIRES: swift_feature_ObjCImplementation
 
 protocol EmptySwiftProto {}
 
+// expected-note@+1 {{previously implemented here}}
 @objc @implementation extension ObjCClass: EmptySwiftProto, EmptyObjCProto {
-  // expected-note@-1 {{previously implemented here}}
-  // expected-error@-2 {{extension for main class interface should provide implementation for instance method 'method(fromHeader4:)'}}
-  // expected-error@-3 {{extension for main class interface should provide implementation for property 'propertyFromHeader9'}}
-  // FIXME: give better diagnostic expected-error@-4 {{extension for main class interface should provide implementation for property 'propertyFromHeader8'}}
-  // FIXME: give better diagnostic expected-error@-5 {{extension for main class interface should provide implementation for property 'propertyFromHeader7'}}
-  // FIXME: give better diagnostic expected-error@-6 {{extension for main class interface should provide implementation for instance method 'method(fromHeader3:)'}}
-  // expected-error@-7 {{'@objc @implementation' extension cannot add conformance to 'EmptySwiftProto'; add this conformance with an ordinary extension}}
-  // expected-error@-8 {{'@objc @implementation' extension cannot add conformance to 'EmptyObjCProto'; add this conformance in the Objective-C header}}
-  // expected-error@-9 {{extension for main class interface should provide implementation for instance method 'extensionMethod(fromHeader2:)'}}
+  // expected-error@-1 {{'@objc @implementation' extension cannot add conformance to 'EmptySwiftProto'; add this conformance with an ordinary extension}}
+  // expected-error@-2 {{'@objc @implementation' extension cannot add conformance to 'EmptyObjCProto'; add this conformance in the Objective-C header}}
+  // expected-error@-3 {{extension for main class interface does not provide all required implementations}}
+  // expected-note@-4 {{missing instance method 'method(fromHeader4:)'}} {{none}}
+  // expected-note@-5 {{missing property 'propertyFromHeader9'}} {{none}}
+  // FIXME: give better diagnostic expected-note@-6 {{missing property 'propertyFromHeader8'}} {{none}}
+  // FIXME: give better diagnostic expected-note@-7 {{missing property 'propertyFromHeader7'}} {{none}}
+  // FIXME: give better diagnostic expected-note@-8 {{missing instance method 'method(fromHeader3:)'}} {{none}}
+  // expected-note@-9 {{missing instance method 'extensionMethod(fromHeader2:)'}} {{none}}
+  // expected-note@-10 {{missing property 'readonlyPropertyFromHeader7'}}
+  // expected-note@-11 {{add stubs for missing '@implementation' requirements}} {{77-77=\n    @objc(methodFromHeader3:)\n    open func method(fromHeader3 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(methodFromHeader4:)\n    open func method(fromHeader4 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(propertyFromHeader7)\n    open var propertyFromHeader7: Int32\n\n    @objc(propertyFromHeader8)\n    open var propertyFromHeader8: Int32\n\n    @objc(propertyFromHeader9)\n    open var propertyFromHeader9: Int32\n\n    @objc(readonlyPropertyFromHeader7)\n    open let readonlyPropertyFromHeader7: Int32\n\n    @objc(extensionMethodFromHeader2:)\n    open func extensionMethod(fromHeader2 param: Int32) {\n        <#code#>\n    \}\n}}
 
   func method(fromHeader1: CInt) {
     // OK, provides an implementation for the header's method.
@@ -233,10 +236,14 @@ protocol EmptySwiftProto {}
   // expected-error@-1 {{property 'rdar122280735' of type '(() -> ()) -> Void' does not match type '(@escaping () -> Void) -> Void' declared by the header}}
 }
 
+// expected-note@+1 {{'PresentAdditions' previously declared here}}
 @objc(PresentAdditions) @implementation extension ObjCClass {
-  // expected-note@-1 {{'PresentAdditions' previously declared here}}
-  // expected-error@-2 {{extension for category 'PresentAdditions' should provide implementation for instance method 'categoryMethod(fromHeader4:)'}}
-  // FIXME: give better diagnostic expected-error@-3 {{extension for category 'PresentAdditions' should provide implementation for instance method 'categoryMethod(fromHeader3:)'}}
+  // expected-error@-1 {{extension for category 'PresentAdditions' does not provide all required implementations}}
+  // expected-note@-2 {{missing instance method 'categoryMethod(fromHeader4:)'}} {{none}}
+  // FIXME: give better diagnostic expected-note@-3 {{missing instance method 'categoryMethod(fromHeader3:)'}} {{none}}
+  // expected-note@-4 {{missing property 'categoryPropertyFromHeader5'}} {{none}}
+  // expected-note@-5 {{missing property 'categoryReadonlyPropertyFromHeader1'}} {{none}}
+  // expected-note@-6 {{add stubs for missing '@implementation' requirements}} {{62-62=\n    @objc(categoryMethodFromHeader3:)\n    open func categoryMethod(fromHeader3 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(categoryMethodFromHeader4:)\n    open func categoryMethod(fromHeader4 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(categoryPropertyFromHeader5)\n    open var categoryPropertyFromHeader5: Int32 {\n        get {\n            <#code#>\n        \}\n        set {\n            <#code#>\n        \}\n    \}\n\n    @objc(categoryReadonlyPropertyFromHeader1)\n    open var categoryReadonlyPropertyFromHeader1: Int32 {\n        <#code#>\n    \}\n}}
 
   func method(fromHeader3: CInt) {
     // FIXME: should emit expected-DISABLED-error@-1 {{instance method 'method(fromHeader3:)' should be implemented in extension for main class interface, not category 'PresentAdditions'}}
@@ -295,7 +302,9 @@ protocol EmptySwiftProto {}
 }
 
 @objc(SwiftNameTests) @implementation extension ObjCClass {
-  // expected-error@-1 {{extension for category 'SwiftNameTests' should provide implementation for instance method 'methodSwiftName6B()'}}
+  // expected-error@-1 {{extension for category 'SwiftNameTests' does not provide all required implementations}}
+  // expected-note@-2 {{missing instance method 'methodSwiftName6B()'}} {{none}}
+  // expected-note@-3 {{add stub for missing '@implementation' requirement}} {{60-60=\n    @objc(methodObjCName6B)\n    open func methodSwiftName6B() {\n        <#code#>\n    \}\n}}
 
   func methodSwiftName1() {
     // expected-error@-1 {{selector 'methodSwiftName1' for instance method 'methodSwiftName1()' not found in header; did you mean 'methodObjCName1'?}} {{3-3=@objc(methodObjCName1) }}
@@ -363,6 +372,10 @@ protocol EmptySwiftProto {}
 }
 
 @objc(Effects) @implementation extension ObjCClass {
+  // expected-error@-1 {{extension for category 'Effects' does not provide all required implementations}}
+  // expected-note@-2 {{missing instance method 'doSomethingMissingAndAsynchronous()' or 'doSomethingMissingAndAsynchronous(completionHandler:)'}}
+  // expected-note@-3 {{add stub for missing '@implementation' requirement}} {{53-53=\n    @objc(doSomethingMissingAndAsynchronousWithCompletionHandler:)\n    open func doSomethingMissingAndAsynchronous() async throws -> Any {\n        <#code#>\n    \}\n}}
+
   @available(SwiftStdlib 5.1, *)
   public func doSomethingAsynchronous() async throws -> Any {
     return self
@@ -406,7 +419,9 @@ protocol EmptySwiftProto {}
 }
 
 @objc(Conformance) @implementation extension ObjCClass {
-  // expected-error@-1 {{extension for category 'Conformance' should provide implementation for instance method 'requiredMethod2()'}}
+  // expected-error@-1 {{extension for category 'Conformance' does not provide all required implementations}}
+  // expected-note@-2 {{missing instance method 'requiredMethod2()'}} {{none}}
+  // expected-note@-3 {{add stub for missing '@implementation' requirement}} {{57-57=\n    @objc(requiredMethod2)\n    open func requiredMethod2() {\n        <#code#>\n    \}\n}}
   // no-error concerning 'optionalMethod2()'
 
   func requiredMethod1() {}
@@ -432,20 +447,22 @@ protocol EmptySwiftProto {}
 }
 
 @objc(TypeMatchOptionalityInvalid) @implementation extension ObjCClass {
-  func nonPointerResult() -> CInt! { fatalError() } // expected-error{{method cannot be in an @objc @implementation extension of a class (without final or @nonobjc) because its result type cannot be represented in Objective-C}}
-  func nonPointerArgument(_: CInt!) {} // expected-error {{method cannot be in an @objc @implementation extension of a class (without final or @nonobjc) because the type of the parameter cannot be represented in Objective-C}}
+  func nonPointerResult() -> CInt! { fatalError() } // expected-error{{method cannot be in an '@objc @implementation' extension of a class (without final or '@nonobjc') because its result type cannot be represented in Objective-C}}
+  func nonPointerArgument(_: CInt!) {} // expected-error {{method cannot be in an '@objc @implementation' extension of a class (without final or '@nonobjc') because the type of the parameter cannot be represented in Objective-C}}
 }
 
 @objc(InvalidMembers) @implementation extension ObjCClass {
-  // expected-error@-1 {{extension for category 'InvalidMembers' should provide implementation for instance method 'unimplementedMember()'}}
+  // expected-error@-1 {{extension for category 'InvalidMembers' does not provide all required implementations}}
+  // expected-note@-2 {{missing instance method 'unimplementedMember()'}} {{none}}
+  // expected-note@-3 {{add stub for missing '@implementation' requirement}} {{60-60=\n    @objc(unimplementedMember)\n    open func unimplementedMember() {\n        <#code#>\n    \}\n}}
 
   func nonObjCMethod(_: EmptySwiftProto) {
-    // expected-error@-1 {{method cannot be in an @objc @implementation extension of a class (without final or @nonobjc) because the type of the parameter cannot be represented in Objective-C}}
+    // expected-error@-1 {{method cannot be in an '@objc @implementation' extension of a class (without final or '@nonobjc') because the type of the parameter cannot be represented in Objective-C}}
     // expected-note@-2 {{protocol-constrained type containing protocol 'EmptySwiftProto' cannot be represented in Objective-C}}
   }
 
   private func privateNonObjCMethod(_: EmptySwiftProto) {
-    // expected-error@-1 {{method cannot be in an @objc @implementation extension of a class (without final or @nonobjc) because the type of the parameter cannot be represented in Objective-C}}
+    // expected-error@-1 {{method cannot be in an '@objc @implementation' extension of a class (without final or '@nonobjc') because the type of the parameter cannot be represented in Objective-C}}
     // expected-note@-2 {{protocol-constrained type containing protocol 'EmptySwiftProto' cannot be represented in Objective-C}}
   }
 
@@ -486,7 +503,7 @@ protocol EmptySwiftProto {}
 // expected-warning@-1 {{extension with Objective-C category name 'PresentAdditions' conflicts with previous extension with the same category name; this is an error in the Swift 6 language mode}}
 
 @objc(MissingAdditions) @implementation extension ObjCClass {}
-// expected-error@-1 {{could not find category 'MissingAdditions' on Objective-C class 'ObjCClass'; make sure your umbrella or bridging header imports the header that declares it}}
+// expected-error@-1 {{could not find category 'MissingAdditions' on Objective-C class 'ObjCClass'; make sure you import the module or header that declares it}}
 // expected-note@-2 {{remove arguments to implement the main '@interface' for this class}} {{6-24=}}
 
 @objc @implementation extension ObjCStruct {}
@@ -541,7 +558,7 @@ func CImplFunc2(_: Int32) {
 
 @implementation @_cdecl("CImplFuncMissing")
 func CImplFuncMissing(_: Int32) {
-  // expected-error@-2 {{could not find imported function 'CImplFuncMissing' matching global function 'CImplFuncMissing'; make sure your umbrella or bridging header imports the header that declares it}}
+  // expected-error@-2 {{could not find imported function 'CImplFuncMissing' matching global function 'CImplFuncMissing'; make sure you import the module or header that declares it}}
 }
 
 @implementation @_cdecl("CImplFuncMismatch1")
@@ -597,13 +614,13 @@ func CImplFuncMismatch6a(_: Int32) -> Any! {
 
 @implementation @_cdecl("CImplFuncNameMismatch1")
 func mismatchedName1(_: Int32) {
-  // expected-error@-2 {{could not find imported function 'CImplFuncNameMismatch1' matching global function 'mismatchedName1'; make sure your umbrella or bridging header imports the header that declares it}}
+  // expected-error@-2 {{could not find imported function 'CImplFuncNameMismatch1' matching global function 'mismatchedName1'; make sure you import the module or header that declares it}}
   // FIXME: Improve diagnostic for a partial match.
 }
 
 @implementation @_cdecl("mismatchedName2")
 func CImplFuncNameMismatch2(_: Int32) {
-  // expected-error@-2 {{could not find imported function 'mismatchedName2' matching global function 'CImplFuncNameMismatch2'; make sure your umbrella or bridging header imports the header that declares it}}
+  // expected-error@-2 {{could not find imported function 'mismatchedName2' matching global function 'CImplFuncNameMismatch2'; make sure you import the module or header that declares it}}
   // FIXME: Improve diagnostic for a partial match.
 }
 
@@ -614,14 +631,14 @@ var cImplComputedGlobal1: Int32 {
   @implementation @_cdecl("CImplGetComputedGlobal1")
   get {
     // FIXME: Lookup for vars isn't working yet
-    // expected-error@-3 {{could not find imported function 'CImplGetComputedGlobal1' matching getter for var 'cImplComputedGlobal1'; make sure your umbrella or bridging header imports the header that declares it}}
+    // expected-error@-3 {{could not find imported function 'CImplGetComputedGlobal1' matching getter for var 'cImplComputedGlobal1'; make sure you import the module or header that declares it}}
     return 0
   }
 
   @implementation @_cdecl("CImplSetComputedGlobal1")
   set {
     // FIXME: Lookup for vars isn't working yet
-    // expected-error@-3 {{could not find imported function 'CImplSetComputedGlobal1' matching setter for var 'cImplComputedGlobal1'; make sure your umbrella or bridging header imports the header that declares it}}
+    // expected-error@-3 {{could not find imported function 'CImplSetComputedGlobal1' matching setter for var 'cImplComputedGlobal1'; make sure you import the module or header that declares it}}
     print(newValue)
   }
 }
@@ -635,7 +652,7 @@ extension CImplStruct {
     // FIXME: Add underlying support for this
     // expected-error@-3 {{@_cdecl can only be applied to global functions}}
     // FIXME: Lookup in an enclosing type is not working yet
-    // expected-error@-5 {{could not find imported function 'CImplStructStaticFunc1' matching static method 'staticFunc1'; make sure your umbrella or bridging header imports the header that declares it}}
+    // expected-error@-5 {{could not find imported function 'CImplStructStaticFunc1' matching static method 'staticFunc1'; make sure you import the module or header that declares it}}
   }
 }
 
diff --git a/test/decl/ext/objc_implementation_class_extension.swift b/test/decl/ext/objc_implementation_class_extension.swift
index 123e459d824da..0908f21e3f1f1 100644
--- a/test/decl/ext/objc_implementation_class_extension.swift
+++ b/test/decl/ext/objc_implementation_class_extension.swift
@@ -1,15 +1,17 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -import-underlying-module -Xcc -fmodule-map-file=%S/Inputs/objc_implementation_class_extension.modulemap -target %target-stable-abi-triple -swift-version 5 -enable-library-evolution
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -import-underlying-module -Xcc -fmodule-map-file=%S/Inputs/objc_implementation_class_extension.modulemap -target %target-stable-abi-triple -swift-version 5 -enable-library-evolution
 // REQUIRES: objc_interop
 
 @_implementationOnly import objc_implementation_class_extension_internal
 
 @_objcImplementation extension ObjCClass {
-  // expected-warning@-1 {{extension for main class interface should provide implementation for instance method 'method(fromHeader2:)'}}
-  // expected-warning@-2 {{extension for main class interface should provide implementation for property 'propertyFromHeader2'}}
-  // expected-warning@-3 {{extension for main class interface should provide implementation for instance method 'otherModuleExtensionMethod(fromHeader2:)'}}
-  // expected-warning@-4 {{extension for main class interface should provide implementation for property 'otherModuleExtensionPropertyFromHeader2'}}
-  // expected-warning@-5 {{extension for main class interface should provide implementation for instance method 'extensionMethod(fromHeader2:)'}}
-  // expected-warning@-6 {{extension for main class interface should provide implementation for property 'extensionPropertyFromHeader2'}}
+  // expected-warning@-1 {{extension for main class interface does not provide all required implementations}}
+  // expected-note@-2 {{missing instance method 'method(fromHeader2:)'}} {{none}}
+  // expected-note@-3 {{missing property 'propertyFromHeader2'}} {{none}}
+  // expected-note@-4 {{missing instance method 'otherModuleExtensionMethod(fromHeader2:)'}} {{none}}
+  // expected-note@-5 {{missing property 'otherModuleExtensionPropertyFromHeader2'}} {{none}}
+  // expected-note@-6 {{missing instance method 'extensionMethod(fromHeader2:)'}} {{none}}
+  // expected-note@-7 {{missing property 'extensionPropertyFromHeader2'}} {{none}}
+  // expected-note@-8 {{add stubs for missing '@implementation' requirements}} {{43-43=\n    @objc(methodFromHeader2:)\n    open func method(fromHeader2 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(propertyFromHeader2)\n    open var propertyFromHeader2: Int32\n\n    @objc(otherModuleExtensionMethodFromHeader2:)\n    open func otherModuleExtensionMethod(fromHeader2 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(otherModuleExtensionPropertyFromHeader2)\n    open var otherModuleExtensionPropertyFromHeader2: Int32\n\n    @objc(extensionMethodFromHeader2:)\n    open func extensionMethod(fromHeader2 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(extensionPropertyFromHeader2)\n    open var extensionPropertyFromHeader2: Int32\n}}
 
   @objc func method(fromHeader1: CInt) {}
   @objc private func method(fromHeader2: CInt) {}
diff --git a/test/decl/ext/objc_implementation_conflicts.swift b/test/decl/ext/objc_implementation_conflicts.swift
index 561051ade12d5..2243570d5f6a7 100644
--- a/test/decl/ext/objc_implementation_conflicts.swift
+++ b/test/decl/ext/objc_implementation_conflicts.swift
@@ -1,5 +1,5 @@
-// RUN: %target-typecheck-verify-swift -import-objc-header %S/Inputs/objc_implementation.h -target %target-stable-abi-triple
-// RUN: %target-typecheck-verify-swift -DPRIVATE_MODULE -Xcc -fmodule-map-file=%S/Inputs/objc_implementation_private.modulemap -target %target-stable-abi-triple
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -import-objc-header %S/Inputs/objc_implementation.h -target %target-stable-abi-triple
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -DPRIVATE_MODULE -Xcc -fmodule-map-file=%S/Inputs/objc_implementation_private.modulemap -target %target-stable-abi-triple
 
 // REQUIRES: objc_interop
 
@@ -108,6 +108,8 @@ import objc_implementation_private
     get { return 1 }
   }
 
+  @objc let readonlyPropertyFromHeader7: CInt
+
   @objc fileprivate var propertyNotFromHeader2: CInt
   // OK, provides a nonpublic but ObjC-compatible stored property
 
@@ -229,6 +231,17 @@ import objc_implementation_private
     get { return 1 }
     set {}
   }
+
+  @objc var categoryPropertyFromHeader5: CInt {
+    // OK, provides an implementation with a computed property
+    get { return 1 }
+    set {}
+  }
+
+  @objc var categoryReadonlyPropertyFromHeader1: CInt {
+    // OK, provides an implementation with a computed property
+    get { return 1 }
+  }
 }
 
 @objc class SwiftClass {}
diff --git a/test/decl/ext/objc_implementation_deployment_target.swift b/test/decl/ext/objc_implementation_deployment_target.swift
index 0735cb2225ecd..41d3b79691672 100644
--- a/test/decl/ext/objc_implementation_deployment_target.swift
+++ b/test/decl/ext/objc_implementation_deployment_target.swift
@@ -1,5 +1,5 @@
 // Hardcode x86_64 macOS because Apple Silicon was born ABI-stable
-// RUN: %target-typecheck-verify-swift -import-objc-header %S/Inputs/objc_implementation.h -target x86_64-apple-macosx10.14.3 -enable-experimental-feature ObjCImplementation
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -import-objc-header %S/Inputs/objc_implementation.h -target x86_64-apple-macosx10.14.3 -enable-experimental-feature ObjCImplementation
 // REQUIRES: objc_interop
 // REQUIRES: OS=macosx
 // REQUIRES: swift_feature_ObjCImplementation
diff --git a/test/decl/ext/objc_implementation_early_adopter.swift b/test/decl/ext/objc_implementation_early_adopter.swift
index 223860de60edf..30adc38254698 100644
--- a/test/decl/ext/objc_implementation_early_adopter.swift
+++ b/test/decl/ext/objc_implementation_early_adopter.swift
@@ -1,20 +1,23 @@
-// RUN: %target-typecheck-verify-swift -import-objc-header %S/Inputs/objc_implementation.h -enable-experimental-feature ObjCImplementation -enable-experimental-feature CImplementation -target %target-stable-abi-triple
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -import-objc-header %S/Inputs/objc_implementation.h -enable-experimental-feature ObjCImplementation -enable-experimental-feature CImplementation -target %target-stable-abi-triple
 // REQUIRES: objc_interop
 // REQUIRES: swift_feature_CImplementation
 // REQUIRES: swift_feature_ObjCImplementation
 
 protocol EmptySwiftProto {}
 
+// expected-note@+1 {{previously implemented here}}
 @_objcImplementation extension ObjCClass: EmptySwiftProto, EmptyObjCProto {
-  // expected-note@-1 {{previously implemented here}}
-  // expected-warning@-2 {{extension for main class interface should provide implementation for instance method 'method(fromHeader4:)'}}
-  // expected-warning@-3 {{extension for main class interface should provide implementation for property 'propertyFromHeader9'}}
-  // FIXME: give better diagnostic expected-warning@-4 {{extension for main class interface should provide implementation for property 'propertyFromHeader8'}}
-  // FIXME: give better diagnostic expected-warning@-5 {{extension for main class interface should provide implementation for property 'propertyFromHeader7'}}
-  // FIXME: give better diagnostic expected-warning@-6 {{extension for main class interface should provide implementation for instance method 'method(fromHeader3:)'}}
-  // expected-warning@-7 {{'@objc @implementation' extension cannot add conformance to 'EmptySwiftProto'; add this conformance with an ordinary extension}}
-  // expected-warning@-8 {{'@objc @implementation' extension cannot add conformance to 'EmptyObjCProto'; add this conformance in the Objective-C header}}
-  // expected-warning@-9 {{extension for main class interface should provide implementation for instance method 'extensionMethod(fromHeader2:)'}}
+  // expected-warning@-1 {{'@objc @implementation' extension cannot add conformance to 'EmptySwiftProto'; add this conformance with an ordinary extension}}
+  // expected-warning@-2 {{'@objc @implementation' extension cannot add conformance to 'EmptyObjCProto'; add this conformance in the Objective-C header}}
+  // expected-warning@-3 {{extension for main class interface does not provide all required implementations; this will become an error after adopting '@implementation'}}
+  // expected-note@-4 {{missing instance method 'method(fromHeader4:)'}} {{none}}
+  // expected-note@-5 {{missing property 'propertyFromHeader9'}} {{none}}
+  // FIXME: give better diagnostic expected-note@-6 {{missing property 'propertyFromHeader8'}} {{none}}
+  // FIXME: give better diagnostic expected-note@-7 {{missing property 'propertyFromHeader7'}} {{none}}
+  // FIXME: give better diagnostic expected-note@-8 {{missing instance method 'method(fromHeader3:)'}} {{none}}
+  // expected-note@-9 {{missing instance method 'extensionMethod(fromHeader2:)'}} {{none}}
+  // expected-note@-10 {{missing property 'readonlyPropertyFromHeader7'}}
+  // expected-note@-11 {{add stubs for missing '@implementation' requirements}} {{76-76=\n    @objc(methodFromHeader3:)\n    open func method(fromHeader3 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(methodFromHeader4:)\n    open func method(fromHeader4 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(propertyFromHeader7)\n    open var propertyFromHeader7: Int32\n\n    @objc(propertyFromHeader8)\n    open var propertyFromHeader8: Int32\n\n    @objc(propertyFromHeader9)\n    open var propertyFromHeader9: Int32\n\n    @objc(readonlyPropertyFromHeader7)\n    open let readonlyPropertyFromHeader7: Int32\n\n    @objc(extensionMethodFromHeader2:)\n    open func extensionMethod(fromHeader2 param: Int32) {\n        <#code#>\n    \}\n}}
 
   func method(fromHeader1: CInt) {
     // OK, provides an implementation for the header's method.
@@ -233,10 +236,14 @@ protocol EmptySwiftProto {}
   // expected-warning@-1 {{property 'rdar122280735' of type '(() -> ()) -> Void' does not match type '(@escaping () -> Void) -> Void' declared by the header}}
 }
 
+// expected-note@+1 {{'PresentAdditions' previously declared here}}
 @_objcImplementation(PresentAdditions) extension ObjCClass {
-  // expected-note@-1 {{'PresentAdditions' previously declared here}}
-  // expected-warning@-2 {{extension for category 'PresentAdditions' should provide implementation for instance method 'categoryMethod(fromHeader4:)'; this will become an error after adopting '@implementation'}}
-  // FIXME: give better diagnostic expected-warning@-3 {{extension for category 'PresentAdditions' should provide implementation for instance method 'categoryMethod(fromHeader3:)'; this will become an error after adopting '@implementation'}}
+  // expected-warning@-1 {{extension for category 'PresentAdditions' does not provide all required implementations; this will become an error after adopting '@implementation'}}
+  // expected-note@-2 {{missing instance method 'categoryMethod(fromHeader4:)'}} {{none}}
+  // FIXME: give better diagnostic expected-note@-3 {{missing instance method 'categoryMethod(fromHeader3:)'}} {{none}}
+  // expected-note@-4 {{missing property 'categoryPropertyFromHeader5'}} {{none}}
+  // expected-note@-5 {{missing property 'categoryReadonlyPropertyFromHeader1'}} {{none}}
+  // expected-note@-6 {{add stubs for missing '@implementation' requirements}} {{61-61=\n    @objc(categoryMethodFromHeader3:)\n    open func categoryMethod(fromHeader3 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(categoryMethodFromHeader4:)\n    open func categoryMethod(fromHeader4 param: Int32) {\n        <#code#>\n    \}\n\n    @objc(categoryPropertyFromHeader5)\n    open var categoryPropertyFromHeader5: Int32 {\n        get {\n            <#code#>\n        \}\n        set {\n            <#code#>\n        \}\n    \}\n\n    @objc(categoryReadonlyPropertyFromHeader1)\n    open var categoryReadonlyPropertyFromHeader1: Int32 {\n        <#code#>\n    \}\n}}
 
   func method(fromHeader3: CInt) {
     // FIXME: should emit expected-DISABLED-error@-1 {{instance method 'method(fromHeader3:)' should be implemented in extension for main class interface, not category 'PresentAdditions'}}
@@ -295,7 +302,9 @@ protocol EmptySwiftProto {}
 }
 
 @_objcImplementation(SwiftNameTests) extension ObjCClass {
-  // expected-warning@-1 {{extension for category 'SwiftNameTests' should provide implementation for instance method 'methodSwiftName6B()'; this will become an error after adopting '@implementation'}}
+  // expected-warning@-1 {{extension for category 'SwiftNameTests' does not provide all required implementations; this will become an error after adopting '@implementation'}}
+  // expected-note@-2 {{missing instance method 'methodSwiftName6B()'}} {{none}}
+  // expected-note@-3 {{add stub for missing '@implementation' requirement}} {{59-59=\n    @objc(methodObjCName6B)\n    open func methodSwiftName6B() {\n        <#code#>\n    \}\n}}
 
   func methodSwiftName1() {
     // expected-warning@-1 {{selector 'methodSwiftName1' for instance method 'methodSwiftName1()' not found in header; did you mean 'methodObjCName1'?; this will become an error after adopting '@implementation'}} {{3-3=@objc(methodObjCName1) }}
@@ -363,6 +372,10 @@ protocol EmptySwiftProto {}
 }
 
 @_objcImplementation(Effects) extension ObjCClass {
+  // expected-warning@-1 {{extension for category 'Effects' does not provide all required implementations; this will become an error after adopting '@implementation'}}
+  // expected-note@-2 {{missing instance method 'doSomethingMissingAndAsynchronous()' or 'doSomethingMissingAndAsynchronous(completionHandler:)'}}
+  // expected-note@-3 {{add stub for missing '@implementation' requirement}} {{52-52=\n    @objc(doSomethingMissingAndAsynchronousWithCompletionHandler:)\n    open func doSomethingMissingAndAsynchronous() async throws -> Any {\n        <#code#>\n    \}\n}}
+
   @available(SwiftStdlib 5.1, *)
   public func doSomethingAsynchronous() async throws -> Any {
     return self
@@ -406,7 +419,9 @@ protocol EmptySwiftProto {}
 }
 
 @_objcImplementation(Conformance) extension ObjCClass {
-  // expected-warning@-1 {{extension for category 'Conformance' should provide implementation for instance method 'requiredMethod2()'; this will become an error after adopting '@implementation'}}
+  // expected-warning@-1 {{extension for category 'Conformance' does not provide all required implementations; this will become an error after adopting '@implementation'}}
+  // expected-note@-2 {{missing instance method 'requiredMethod2()'}} {{none}}
+  // expected-note@-3 {{add stub for missing '@implementation' requirement}} {{56-56=\n    @objc(requiredMethod2)\n    open func requiredMethod2() {\n        <#code#>\n    \}\n}}
   // no-error concerning 'optionalMethod2()'
 
   func requiredMethod1() {}
@@ -432,15 +447,17 @@ protocol EmptySwiftProto {}
 }
 
 @_objcImplementation(TypeMatchOptionalityInvalid) extension ObjCClass {
-  func nonPointerResult() -> CInt! { fatalError() } // expected-warning{{method cannot be in an @objc @implementation extension of a class (without final or @nonobjc) because its result type cannot be represented in Objective-C}}
-  func nonPointerArgument(_: CInt!) {} // expected-warning {{method cannot be in an @objc @implementation extension of a class (without final or @nonobjc) because the type of the parameter cannot be represented in Objective-C}}
+  func nonPointerResult() -> CInt! { fatalError() } // expected-warning{{method cannot be in an '@objc @implementation' extension of a class (without final or '@nonobjc') because its result type cannot be represented in Objective-C}}
+  func nonPointerArgument(_: CInt!) {} // expected-warning {{method cannot be in an '@objc @implementation' extension of a class (without final or '@nonobjc') because the type of the parameter cannot be represented in Objective-C}}
 }
 
 @_objcImplementation(InvalidMembers) extension ObjCClass {
-  // expected-warning@-1 {{extension for category 'InvalidMembers' should provide implementation for instance method 'unimplementedMember()'}}
+  // expected-warning@-1 {{extension for category 'InvalidMembers' does not provide all required implementations}}
+  // expected-note@-2 {{missing instance method 'unimplementedMember()'}} {{none}}
+  // expected-note@-3 {{add stub for missing '@implementation' requirement}} {{59-59=\n    @objc(unimplementedMember)\n    open func unimplementedMember() {\n        <#code#>\n    \}\n}}
 
   func nonObjCMethod(_: EmptySwiftProto) {
-    // expected-warning@-1 {{method cannot be in an @objc @implementation extension of a class (without final or @nonobjc) because the type of the parameter cannot be represented in Objective-C}}
+    // expected-warning@-1 {{method cannot be in an '@objc @implementation' extension of a class (without final or '@nonobjc') because the type of the parameter cannot be represented in Objective-C}}
     // expected-note@-2 {{protocol-constrained type containing protocol 'EmptySwiftProto' cannot be represented in Objective-C}}
   }
 
@@ -490,7 +507,7 @@ protocol EmptySwiftProto {}
 // expected-warning@-1 {{extension with Objective-C category name 'PresentAdditions' conflicts with previous extension with the same category name; this is an error in the Swift 6 language mode}}
 
 @_objcImplementation(MissingAdditions) extension ObjCClass {}
-// expected-error@-1 {{could not find category 'MissingAdditions' on Objective-C class 'ObjCClass'; make sure your umbrella or bridging header imports the header that declares it}}
+// expected-error@-1 {{could not find category 'MissingAdditions' on Objective-C class 'ObjCClass'; make sure you import the module or header that declares it}}
 // expected-note@-2 {{remove arguments to implement the main '@interface' for this class}} {{21-39=}}
 
 @_objcImplementation extension ObjCStruct {}
@@ -532,7 +549,7 @@ func CImplFunc2(_: Int32) {
 
 @_objcImplementation @_cdecl("CImplFuncMissing")
 func CImplFuncMissing(_: Int32) {
-  // expected-error@-2 {{could not find imported function 'CImplFuncMissing' matching global function 'CImplFuncMissing'; make sure your umbrella or bridging header imports the header that declares it}}
+  // expected-error@-2 {{could not find imported function 'CImplFuncMissing' matching global function 'CImplFuncMissing'; make sure you import the module or header that declares it}}
 }
 
 @_objcImplementation @_cdecl("CImplFuncMismatch1")
@@ -588,13 +605,13 @@ func CImplFuncMismatch6a(_: Int32) -> Any! {
 
 @_objcImplementation @_cdecl("CImplFuncNameMismatch1")
 func mismatchedName1(_: Int32) {
-  // expected-error@-2 {{could not find imported function 'CImplFuncNameMismatch1' matching global function 'mismatchedName1'; make sure your umbrella or bridging header imports the header that declares it}}
+  // expected-error@-2 {{could not find imported function 'CImplFuncNameMismatch1' matching global function 'mismatchedName1'; make sure you import the module or header that declares it}}
   // FIXME: Improve diagnostic for a partial match.
 }
 
 @_objcImplementation @_cdecl("mismatchedName2")
 func CImplFuncNameMismatch2(_: Int32) {
-  // expected-error@-2 {{could not find imported function 'mismatchedName2' matching global function 'CImplFuncNameMismatch2'; make sure your umbrella or bridging header imports the header that declares it}}
+  // expected-error@-2 {{could not find imported function 'mismatchedName2' matching global function 'CImplFuncNameMismatch2'; make sure you import the module or header that declares it}}
   // FIXME: Improve diagnostic for a partial match.
 }
 
@@ -605,14 +622,14 @@ var cImplComputedGlobal1: Int32 {
   @_objcImplementation @_cdecl("CImplGetComputedGlobal1")
   get {
     // FIXME: Lookup for vars isn't working yet
-    // expected-error@-3 {{could not find imported function 'CImplGetComputedGlobal1' matching getter for var 'cImplComputedGlobal1'; make sure your umbrella or bridging header imports the header that declares it}}
+    // expected-error@-3 {{could not find imported function 'CImplGetComputedGlobal1' matching getter for var 'cImplComputedGlobal1'; make sure you import the module or header that declares it}}
     return 0
   }
 
   @_objcImplementation @_cdecl("CImplSetComputedGlobal1")
   set {
     // FIXME: Lookup for vars isn't working yet
-    // expected-error@-3 {{could not find imported function 'CImplSetComputedGlobal1' matching setter for var 'cImplComputedGlobal1'; make sure your umbrella or bridging header imports the header that declares it}}
+    // expected-error@-3 {{could not find imported function 'CImplSetComputedGlobal1' matching setter for var 'cImplComputedGlobal1'; make sure you import the module or header that declares it}}
     print(newValue)
   }
 }
@@ -626,7 +643,7 @@ extension CImplStruct {
     // FIXME: Add underlying support for this
     // expected-error@-3 {{@_cdecl can only be applied to global functions}}
     // FIXME: Lookup in an enclosing type is not working yet
-    // expected-error@-5 {{could not find imported function 'CImplStructStaticFunc1' matching static method 'staticFunc1'; make sure your umbrella or bridging header imports the header that declares it}}
+    // expected-error@-5 {{could not find imported function 'CImplStructStaticFunc1' matching static method 'staticFunc1'; make sure you import the module or header that declares it}}
   }
 }
 
diff --git a/test/decl/ext/objc_implementation_features.swift b/test/decl/ext/objc_implementation_features.swift
index a3230928c5da2..3d5343fa2f3cf 100644
--- a/test/decl/ext/objc_implementation_features.swift
+++ b/test/decl/ext/objc_implementation_features.swift
@@ -1,14 +1,15 @@
 // REQUIRES: objc_interop
 
-// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -typecheck %s -import-objc-header %S/Inputs/objc_implementation.h 2>&1 | %FileCheck %s
+// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -typecheck %s -import-objc-header %S/Inputs/objc_implementation.h >%t.txt 2>&1
+// RUN: %FileCheck %s --input-file %t.txt
 
 // CHECK-DAG: objc_implementation_features.swift:[[@LINE+1]]:{{[0-9]+}}: warning: '@_objcImplementation' is deprecated; use '@implementation' instead
 @_objcImplementation(EmptyCategory) extension ObjCClass {}
 
-// CHECK-DAG: objc_implementation_features.swift:[[@LINE+2]]:{{[0-9]+}}: warning: extension for main class interface should provide implementation for instance method 'subclassMethod(fromHeader1:)'; this will become an error after adopting '@implementation'
+// CHECK-DAG: objc_implementation_features.swift:[[@LINE+2]]:{{[0-9]+}}: warning: extension for main class interface does not provide all required implementations; this will become an error after adopting '@implementation'
 // CHECK-NOT: objc_implementation_features.swift:[[@LINE+1]]:{{[0-9]+}}: warning: '@_objcImplementation' is deprecated; use '@implementation' instead
 @_objcImplementation extension ObjCSubclass {}
 
-// CHECK-DAG: objc_implementation_features.swift:[[@LINE+2]]:{{[0-9]+}}: error: extension for main class interface should provide implementation for initializer 'init()'{{$}}
+// CHECK-DAG: objc_implementation_features.swift:[[@LINE+2]]:{{[0-9]+}}: error: extension for main class interface does not provide all required implementations{{$}}
 // CHECK-NOT: objc_implementation_features.swift:[[@LINE+1]]:{{[0-9]+}}: error: 'implementation' attribute is only valid when experimental feature ObjCImplementation is enabled
 @objc @implementation extension ObjCBasicInitClass {}
diff --git a/test/decl/ext/specialize.swift b/test/decl/ext/specialize.swift
index 72bef5ee947d7..84c1faadd7b00 100644
--- a/test/decl/ext/specialize.swift
+++ b/test/decl/ext/specialize.swift
@@ -86,3 +86,9 @@ class State {
 extension Test.Key<State> {
   static let state = Self<State>()
 }
+
+protocol P {}
+struct S: P {}
+
+extension Sequence<any P> where Self == [S] {}
+// expected-error@-1 {{generic signature requires types 'S' and 'any P' to be the same}}
diff --git a/test/decl/ext/typealias.swift b/test/decl/ext/typealias.swift
index c5917a0a0d565..3d33655f7a80b 100644
--- a/test/decl/ext/typealias.swift
+++ b/test/decl/ext/typealias.swift
@@ -78,3 +78,16 @@ extension FooIntBarFloatDoubleInner {
   }
 }
 
+struct Foo2<T1, T2, T3,> {}
+
+typealias Bar2<
+  T1,
+  T2,
+> = Foo2<
+  T1,
+  T2,
+  Bool,
+>
+
+let _ = Foo2<Int, Bool, String,>.self
+let _ = Bar2<Int, Bool,>()
diff --git a/test/decl/func/functions.swift b/test/decl/func/functions.swift
index 92542cc96a103..96dd8398a2036 100644
--- a/test/decl/func/functions.swift
+++ b/test/decl/func/functions.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-objc-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-objc-interop
 
 infix operator ====
 infix operator <<<<
diff --git a/test/decl/func/typed_throws.swift b/test/decl/func/typed_throws.swift
index c453ed0d27f61..6a3282621c12f 100644
--- a/test/decl/func/typed_throws.swift
+++ b/test/decl/func/typed_throws.swift
@@ -192,7 +192,7 @@ enum G_E<T> {
 
 func testArrMap(arr: [String]) {
   _ = mapArray(arr, body: G_E<Int>.tuple)
-  // expected-error@-1{{cannot convert value of type '((x: Int, y: Int)) -> G_E<Int>' to expected argument type '(String) -> G_E<Int>'}}
+  // expected-error@-1{{conflicting arguments to generic parameter 'T' ('String' vs. '(x: Int, y: Int)')}}
 }
 
 // Shadowing of typed-throws Result.get() addresses a source compatibility
@@ -216,3 +216,8 @@ struct NotAnError<T> {}
 
 func badThrowingFunctionType<T>(_: () throws(NotAnError<T>) -> ()) {}
 // expected-error@-1 {{thrown type 'NotAnError<T>' does not conform to the 'Error' protocol}}
+
+struct GenericError<T>: Error {}
+
+func placeholderThrowing1() throws(_) {} // expected-error {{type placeholder not allowed here}}
+func placeholderThrowing2() throws(GenericError<_>) {} // expected-error {{type placeholder not allowed here}}
diff --git a/test/decl/func/typed_throws_availability.swift b/test/decl/func/typed_throws_availability.swift
index 137672c46017b..7e021562b7608 100644
--- a/test/decl/func/typed_throws_availability.swift
+++ b/test/decl/func/typed_throws_availability.swift
@@ -9,7 +9,7 @@ enum MyError: Error {
 }
 
 func bad() -> Any.Type {
-  // expected-note@-1{{add @available attribute to enclosing global function}}
+  // expected-note@-1{{add '@available' attribute to enclosing global function}}
   typealias Fn = () throws(MyError) -> ()
   // expected-error@+2{{runtime support for typed throws function types is only available in macOS 15.0.0 or newer}}
   // expected-note@+1{{add 'if #available' version check}}
diff --git a/test/decl/init/basic_init.swift b/test/decl/init/basic_init.swift
index 6b07ac0e47d62..29e8d82d37d2d 100644
--- a/test/decl/init/basic_init.swift
+++ b/test/decl/init/basic_init.swift
@@ -10,7 +10,7 @@ class C {
 	init() {}
 }
 
-typealias t = t // expected-error {{type alias 't' references itself}} expected-note {{while resolving type 't'}} expected-note {{through reference here}}
+typealias t = t // expected-error {{type alias 't' references itself}} expected-note {{while resolving type 't'}}
 
 extension Foo {
   convenience init() {} // expected-error{{invalid redeclaration of synthesized 'init()'}}
@@ -25,7 +25,7 @@ class InitSubclass: InitClass {}
 // expected-note@-1{{implicit initializer 'init(baz:)' declared here}}
 // expected-note@-2{{implicit initializer 'init(bar:)' declared here}}
 extension InitSubclass {
-  convenience init(arg: Bool) {} // expected-error{{non-@objc initializer 'init(arg:)' declared in 'InitClass' cannot be overridden from extension}}
+  convenience init(arg: Bool) {} // expected-error{{non-'@objc' initializer 'init(arg:)' declared in 'InitClass' cannot be overridden from extension}}
   convenience override init(baz: Int) {}
   // expected-error@-1 {{initializer 'init(baz:)' with Objective-C selector 'initWithBaz:' conflicts with implicit initializer 'init(baz:)' with the same Objective-C selector}}
   // expected-error@-2 {{cannot override a non-dynamic class declaration from an extension}}
diff --git a/test/decl/init/resilience-cross-module.swift b/test/decl/init/resilience-cross-module.swift
index b14c2486e4ed6..cbeb40be323b9 100644
--- a/test/decl/init/resilience-cross-module.swift
+++ b/test/decl/init/resilience-cross-module.swift
@@ -3,11 +3,11 @@
 // RUN: %target-swift-frontend -emit-module -enable-library-evolution -emit-module-path=%t/resilient_struct.swiftmodule -module-name=resilient_struct %S/../../Inputs/resilient_struct.swift
 // RUN: %target-swift-frontend -emit-module -enable-library-evolution -emit-module-path=%t/resilient_protocol.swiftmodule -module-name=resilient_protocol %S/../../Inputs/resilient_protocol.swift
 
-// RUN: %target-swift-frontend -typecheck -swift-version 4 -verify -I %t %s
-// RUN: %target-swift-frontend -typecheck -swift-version 4 -verify -enable-library-evolution -I %t %s
+// RUN: %target-swift-frontend -typecheck -swift-version 4 -verify -verify-ignore-unrelated -I %t %s
+// RUN: %target-swift-frontend -typecheck -swift-version 4 -verify -verify-ignore-unrelated -enable-library-evolution -I %t %s
 
-// RUN: %target-swift-frontend -typecheck -swift-version 5 -verify -I %t %s
-// RUN: %target-swift-frontend -typecheck -swift-version 5 -verify -enable-library-evolution -I %t %s
+// RUN: %target-swift-frontend -typecheck -swift-version 5 -verify -verify-ignore-unrelated -I %t %s
+// RUN: %target-swift-frontend -typecheck -swift-version 5 -verify -verify-ignore-unrelated -enable-library-evolution -I %t %s
 
 import resilient_struct
 import resilient_protocol
diff --git a/test/decl/nested/protocol.swift b/test/decl/nested/protocol.swift
index fc83d4a8dc94d..1dd52b70694c8 100644
--- a/test/decl/nested/protocol.swift
+++ b/test/decl/nested/protocol.swift
@@ -257,7 +257,7 @@ extension OuterProtocol {
 // 'OtherGenericClass', so the occurrence of 'OtherGenericClass'
 // in 'InnerProtocol' is not "in context" with implicitly
 // inferred generic arguments <T, U>.
-class OtherGenericClass<T, U> { // expected-note {{generic type 'OtherGenericClass' declared here}}
+class OtherGenericClass<T, U> { // expected-note {{generic class 'OtherGenericClass' declared here}}
   protocol InnerProtocol : OtherGenericClass { }
   // expected-error@-1 {{protocol 'InnerProtocol' cannot be nested in a generic context}}
   // expected-error@-2 {{reference to generic type 'OtherGenericClass' requires arguments in <...>}}
@@ -338,7 +338,7 @@ enum SillyRawEnum : SillyProtocol.InnerClass {} // expected-error {{an enum with
 
 protocol SillyProtocol {
   class InnerClass<T> {} // expected-error {{type 'InnerClass' cannot be nested in protocol 'SillyProtocol'}}
-  // expected-note@-1 {{generic type 'InnerClass' declared here}}
+  // expected-note@-1 {{generic class 'InnerClass' declared here}}
 }
 
 protocol SelfDotTest {
diff --git a/test/decl/nested/type_in_type.swift b/test/decl/nested/type_in_type.swift
index 76efd11a34b66..cbfee535b778d 100644
--- a/test/decl/nested/type_in_type.swift
+++ b/test/decl/nested/type_in_type.swift
@@ -205,7 +205,7 @@ struct GS<T> { //expected-note {{arguments to generic parameter 'T' ('T' and 'In
     }
   }
 
-  struct NestedGeneric<U> { // expected-note{{generic type 'NestedGeneric' declared here}}
+  struct NestedGeneric<U> { // expected-note{{generic struct 'NestedGeneric' declared here}}
     func fff() -> (GS, NestedGeneric) {
       let gs = GS()
       let ns = NestedGeneric()
@@ -383,7 +383,7 @@ struct Kitten : ExpressibleByCatLiteral {}
 struct Puppy : ExpressibleByDogLiteral {}
 
 struct Claws<A: ExpressibleByCatLiteral> { // expected-note 3 {{'A' declared as parameter to type 'Claws'}}
-  struct Fangs<B: ExpressibleByDogLiteral> { } // expected-note {{where 'B' = 'NotADog'}}
+  struct Fangs<B: ExpressibleByDogLiteral> { } // expected-note 3 {{where 'B' = 'NotADog'}}
 }
 
 struct NotADog {}
@@ -407,9 +407,14 @@ do {
   // expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{36-36=<<#A: ExpressibleByCatLiteral#>>}}
   let _: Claws.Fangs<NotADog> = something()
   // expected-error@-1 {{generic parameter 'A' could not be inferred}}
+  // expected-error@-2 {{generic struct 'Fangs' requires that 'NotADog' conform to 'ExpressibleByDogLiteral'}}
+
+  // FIXME: We get a duplicate diagnostic here because we don't differentiate
+  // constraint locators when opening generic requirements, we just use a
+  // locator for the top-level TypeRepr.
   _ = Claws.Fangs<NotADog>()
   // expected-error@-1 {{generic parameter 'A' could not be inferred}}
-  // expected-error@-2 {{generic struct 'Fangs' requires that 'NotADog' conform to 'ExpressibleByDogLiteral'}}
+  // expected-error@-2 2{{generic struct 'Fangs' requires that 'NotADog' conform to 'ExpressibleByDogLiteral'}}
   // expected-note@-3 {{explicitly specify the generic arguments to fix this issue}} {{12-12=<<#A: ExpressibleByCatLiteral#>>}}
 }
 
@@ -427,3 +432,17 @@ extension OuterGeneric.MidNonGeneric {
 
   }
 }
+
+protocol P {}
+
+struct A<T> {}
+extension A where T: P { // expected-note {{where 'T' = 'T'}}
+  struct B<U> {
+    init(_ u: U) {}
+  }
+}
+extension A {
+  func bar() {
+    B(0) // expected-error {{referencing generic struct 'B' on 'A' requires that 'T' conform to 'P'}}
+  }
+}
diff --git a/test/decl/objc_redeclaration.swift b/test/decl/objc_redeclaration.swift
index 9c196ac31d21f..297f536a945ba 100644
--- a/test/decl/objc_redeclaration.swift
+++ b/test/decl/objc_redeclaration.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -module-name ZZZ %s -disable-objc-attr-requires-foundation-module -verify -verify-ignore-unknown
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -module-name ZZZ %s -disable-objc-attr-requires-foundation-module -verify -verify-ignore-unrelated -verify-ignore-unknown
 
 import Foundation
 
diff --git a/test/decl/operator/lookup.swift b/test/decl/operator/lookup.swift
index fb861ce5b7a92..791c87c80cabe 100644
--- a/test/decl/operator/lookup.swift
+++ b/test/decl/operator/lookup.swift
@@ -5,7 +5,7 @@
 // RUN: %target-swift-frontend -emit-module %S/Inputs/lookup_moduleB.swift -module-name B -o %t -I %t
 // RUN: %target-swift-frontend -emit-module %S/Inputs/lookup_moduleA.swift -module-name A -o %t -I %t
 // RUN: %target-swift-frontend -emit-module %S/Inputs/lookup_module_exportsAC.swift -module-name ExportsAC -o %t -I %t
-// RUN: %target-swift-frontend -typecheck -verify -primary-file %s %S/Inputs/lookup_other.swift %S/Inputs/lookup_other2.swift %S/Inputs/lookup_other_noncompat.swift -I %t -enable-new-operator-lookup
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -primary-file %s %S/Inputs/lookup_other.swift %S/Inputs/lookup_other2.swift %S/Inputs/lookup_other_noncompat.swift -I %t -enable-new-operator-lookup
 
 import ExportsAC
 import B
diff --git a/test/decl/operator/lookup_compatibility.swift b/test/decl/operator/lookup_compatibility.swift
index 08d52d3e97b51..7d62c2bf5cfca 100644
--- a/test/decl/operator/lookup_compatibility.swift
+++ b/test/decl/operator/lookup_compatibility.swift
@@ -5,7 +5,7 @@
 // RUN: %target-swift-frontend -emit-module %S/Inputs/lookup_moduleB.swift -module-name B -o %t -I %t
 // RUN: %target-swift-frontend -emit-module %S/Inputs/lookup_moduleA.swift -module-name A -o %t -I %t
 // RUN: %target-swift-frontend -emit-module %S/Inputs/lookup_module_exportsAC.swift -module-name ExportsAC -o %t -I %t
-// RUN: %target-swift-frontend -typecheck -verify -primary-file %s %S/Inputs/lookup_other.swift %S/Inputs/lookup_other2.swift %S/Inputs/lookup_other_compat.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -primary-file %s %S/Inputs/lookup_other.swift %S/Inputs/lookup_other2.swift %S/Inputs/lookup_other_compat.swift -I %t
 
 import ExportsAC
 import B
diff --git a/test/decl/protocol/associated_type_availability.swift b/test/decl/protocol/associated_type_availability.swift
index 1a8bb85a3ea39..4c833d2b1e05d 100644
--- a/test/decl/protocol/associated_type_availability.swift
+++ b/test/decl/protocol/associated_type_availability.swift
@@ -19,7 +19,7 @@ struct ModelP1<A, B: P>: P1 {
 // Associated types in where clauses
 func testWhereBad<T: P1, U>(_: T) where T.B == U { }
 // expected-error@-1{{'B' is only available in macOS 13 or newer}}
-// expected-note@-2{{add @available attribute to enclosing global function}}
+// expected-note@-2{{add '@available' attribute to enclosing global function}}
 
 @available(macOS 13, *)
 func testWhereGood<T: P1, U>(_: T) where T.B == U { }
@@ -27,7 +27,7 @@ func testWhereGood<T: P1, U>(_: T) where T.B == U { }
 // Associated types in opaque parameter position
 func testPrimaryOpaqueParamBad<U>(_: some P1<some Any, U>) {}
 // expected-error@-1 2{{'B' is only available in macOS 13 or newer}}
-// expected-note@-2 2{{add @available attribute to enclosing global function}}
+// expected-note@-2 2{{add '@available' attribute to enclosing global function}}
 
 @available(macOS 13, *)
 func testPrimaryOpaqueParamGood<U: P>(_: some P1<some Any, U>) {}
@@ -35,7 +35,7 @@ func testPrimaryOpaqueParamGood<U: P>(_: some P1<some Any, U>) {}
 // Associated types in opaque result position
 func testPrimaryOpaqueResultBad<U: P>() -> some P1<String, U> {
 // expected-error@-1{{'B' is only available in macOS 13 or newer}}
-// expected-note@-2 2{{add @available attribute to enclosing global function}}
+// expected-note@-2 2{{add '@available' attribute to enclosing global function}}
   return ModelP1<String, U>()
   // expected-error@-1{{'ModelP1' is only available in macOS 13 or newer}}
   // expected-note@-2{{add 'if #available' version check}}
@@ -49,7 +49,7 @@ func testPrimaryOpaqueResultGood<U: P>() -> some P1<String, U> {
 // Associated types in existentials
 func testPrimaryExistentialBad<U>(_: any P1<Int, U>) {}
 // expected-error@-1{{'B' is only available in macOS 13 or newer}}
-// expected-note@-2{{add @available attribute to enclosing global function}}
+// expected-note@-2{{add '@available' attribute to enclosing global function}}
 
 @available(macOS 13, *)
 func testPrimaryExistentialGood<U>(_: any P1<Int, U>) {}
@@ -74,7 +74,7 @@ struct ModelP2: P2 {
 }
 
 extension ModelP2 {
-  // expected-note@-1{{add @available attribute to enclosing extension}}
+  // expected-note@-1{{add '@available' attribute to enclosing extension}}
 
   // Ok, the inferred typealias for A is always available.
   func takesA(_ a: A) {}
@@ -82,7 +82,7 @@ extension ModelP2 {
   // Bad, the inferred typealias for B is introduced with associated type B.
   func takesB(_ b: B) {}
   // expected-error@-1{{'B' is only available in macOS 14 or newer}}
-  // expected-note@-2{{add @available attribute to enclosing instance method}}
+  // expected-note@-2{{add '@available' attribute to enclosing instance method}}
 }
 
 protocol P3 {
diff --git a/test/decl/protocol/associated_type_overrides_conformances_cross_module.swift b/test/decl/protocol/associated_type_overrides_conformances_cross_module.swift
index 86920f46630e1..f1437fc8eee9f 100644
--- a/test/decl/protocol/associated_type_overrides_conformances_cross_module.swift
+++ b/test/decl/protocol/associated_type_overrides_conformances_cross_module.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -D M -emit-module -module-name M -parse-as-library -o %t %s
-// RUN: %target-typecheck-verify-swift -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t
 
 #if M
 
diff --git a/test/decl/protocol/conforms/failure.swift b/test/decl/protocol/conforms/failure.swift
index ebf5c0a166d95..4fe3ff14877f1 100644
--- a/test/decl/protocol/conforms/failure.swift
+++ b/test/decl/protocol/conforms/failure.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 protocol P1 {
   func foo() // expected-note {{protocol requires function 'foo()'}}
diff --git a/test/decl/protocol/conforms/fixit_stub.swift b/test/decl/protocol/conforms/fixit_stub.swift
index 22c26017e7ec9..a799b1dc4f57b 100644
--- a/test/decl/protocol/conforms/fixit_stub.swift
+++ b/test/decl/protocol/conforms/fixit_stub.swift
@@ -1,17 +1,20 @@
 // RUN: %target-typecheck-verify-swift
 
 protocol Protocol1 {
-  func foo(arg1: Int, arg2: String) -> String // expected-note{{protocol requires function 'foo(arg1:arg2:)' with type '(Int, String) -> String'}}
-  func bar() throws -> String // expected-note{{protocol requires function 'bar()' with type '() throws -> String'}}
-  func generic<T>(t: T) // expected-note{{protocol requires function 'generic(t:)' with type '<T> (t: T) -> ()'}}
-  init(arg: Int) // expected-note{{protocol requires initializer 'init(arg:)' with type '(arg: Int)'}}
-  var baz: Int { get } // expected-note{{protocol requires property 'baz' with type 'Int'}}
-  var baz2: Int { get set } // expected-note{{protocol requires property 'baz2' with type 'Int'}}
-  subscript(arg: Int) -> String { get } //expected-note{{rotocol requires subscript with type '(Int) -> String'}}
-  subscript(arg1: Int, arg2: Int) -> String { get set } //expected-note{{protocol requires subscript with type '(Int, Int) -> String'}}
+  func foo(arg1: Int, arg2: String) -> String // expected-note 2{{protocol requires function 'foo(arg1:arg2:)' with type '(Int, String) -> String'}}
+  func bar() throws -> String // expected-note 2{{protocol requires function 'bar()' with type '() throws -> String'}}
+  func generic<T>(t: T) // expected-note 2{{protocol requires function 'generic(t:)' with type '<T> (t: T) -> ()'}}
+  init(arg: Int) // expected-note 2{{protocol requires initializer 'init(arg:)' with type '(arg: Int)'}}
+  var baz: Int { get } // expected-note 2{{protocol requires property 'baz' with type 'Int'}}
+  var baz2: Int { get set } // expected-note 2{{protocol requires property 'baz2' with type 'Int'}}
+  subscript(arg: Int) -> String { get } //expected-note 2{{rotocol requires subscript with type '(Int) -> String'}}
+  subscript(arg1: Int, arg2: Int) -> String { get set } //expected-note 2{{protocol requires subscript with type '(Int, Int) -> String'}}
+}
+
+class Adopter: Protocol1 { // expected-error{{type 'Adopter' does not conform to protocol 'Protocol1'}} expected-note {{add stubs for conformance}} {{27-27=\n    func foo(arg1: Int, arg2: String) -> String {\n        <#code#>\n    \}\n\n    func bar() throws -> String {\n        <#code#>\n    \}\n\n    func generic<T>(t: T) {\n        <#code#>\n    \}\n\n    required init(arg: Int) {\n        <#code#>\n    \}\n\n    let baz: Int\n\n    var baz2: Int\n\n    subscript(arg: Int) -> String {\n        <#code#>\n    \}\n\n    subscript(arg1: Int, arg2: Int) -> String {\n        get {\n            <#code#>\n        \}\n        set {\n            <#code#>\n        \}\n    \}\n}}
 }
 
-class Adopter: Protocol1 { // expected-error{{type 'Adopter' does not conform to protocol 'Protocol1'}} expected-note {{add stubs for conformance}} {{27-27=\n    func foo(arg1: Int, arg2: String) -> String {\n        <#code#>\n    \}\n\n    func bar() throws -> String {\n        <#code#>\n    \}\n\n    func generic<T>(t: T) {\n        <#code#>\n    \}\n\n    required init(arg: Int) {\n        <#code#>\n    \}\n\n    var baz: Int\n\n    var baz2: Int\n\n    subscript(arg: Int) -> String {\n        <#code#>\n    \}\n\n    subscript(arg1: Int, arg2: Int) -> String {\n        get {\n            <#code#>\n        \}\n        set {\n            <#code#>\n        \}\n    \}\n}}
+enum EnumAdopter: Protocol1 { // expected-error{{type 'EnumAdopter' does not conform to protocol 'Protocol1'}} expected-note {{add stubs for conformance}} {{30-30=\n    func foo(arg1: Int, arg2: String) -> String {\n        <#code#>\n    \}\n\n    func bar() throws -> String {\n        <#code#>\n    \}\n\n    func generic<T>(t: T) {\n        <#code#>\n    \}\n\n    init(arg: Int) {\n        <#code#>\n    \}\n\n    var baz: Int {\n        <#code#>\n    \}\n\n    var baz2: Int {\n        get {\n            <#code#>\n        \}\n        set {\n            <#code#>\n        \}\n    \}\n\n    subscript(arg: Int) -> String {\n        <#code#>\n    \}\n\n    subscript(arg1: Int, arg2: Int) -> String {\n        get {\n            <#code#>\n        \}\n        set {\n            <#code#>\n        \}\n    \}\n}}
 }
 
 
diff --git a/test/decl/protocol/conforms/fixit_stub_2.swift b/test/decl/protocol/conforms/fixit_stub_2.swift
index 35665e29948b5..048e1399c528a 100644
--- a/test/decl/protocol/conforms/fixit_stub_2.swift
+++ b/test/decl/protocol/conforms/fixit_stub_2.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %S/Inputs/fixit_stub_mutability_proto_module.swift -emit-module -parse-as-library -o %t
 
-// RUN: %target-swift-frontend -typecheck %s -I %t -verify
+// RUN: %target-swift-frontend -typecheck %s -I %t -verify -verify-ignore-unrelated
 
 protocol P0_A { associatedtype T } // expected-note{{protocol requires nested type 'T'}}
 protocol P0_B { associatedtype T }
@@ -81,10 +81,10 @@ struct Struct1: MutabilityProto { // expected-error{{type 'Struct1' does not con
 
 import fixit_stub_mutability_proto_module
 
-class Class2: ExternalMutabilityProto { // expected-error{{type 'Class2' does not conform to protocol 'ExternalMutabilityProto'}} expected-note{{add stubs for conformance}} {{40-40=\n    func foo() {\n        <#code#>\n    \}\n\n    subscript() -> Int {\n        get {\n            <#code#>\n        \}\n        set(newValue) {\n            <#code#>\n        \}\n    \}\n}}
+class Class2: ExternalMutabilityProto { // expected-error{{type 'Class2' does not conform to protocol 'ExternalMutabilityProto'}} expected-note{{add stubs for conformance}} {{40-40=\n    func foo() {\n        <#code#>\n    \}\n\n    subscript() -> Int {\n        get {\n            <#code#>\n        \}\n        set {\n            <#code#>\n        \}\n    \}\n}}
 }
 
-struct Struct2: ExternalMutabilityProto { // expected-error{{type 'Struct2' does not conform to protocol 'ExternalMutabilityProto'}} expected-note{{add stubs for conformance}} {{42-42=\n    mutating func foo() {\n        <#code#>\n    \}\n\n    subscript() -> Int {\n        mutating get {\n            <#code#>\n        \}\n        nonmutating set(newValue) {\n            <#code#>\n        \}\n    \}\n}}
+struct Struct2: ExternalMutabilityProto { // expected-error{{type 'Struct2' does not conform to protocol 'ExternalMutabilityProto'}} expected-note{{add stubs for conformance}} {{42-42=\n    mutating func foo() {\n        <#code#>\n    \}\n\n    subscript() -> Int {\n        mutating get {\n            <#code#>\n        \}\n        nonmutating set {\n            <#code#>\n        \}\n    \}\n}}
 }
 
 protocol PropertyMutabilityProto {
diff --git a/test/decl/protocol/conforms/fixit_stub_amiguity.swift b/test/decl/protocol/conforms/fixit_stub_amiguity.swift
index 40c981a571221..a8189a8453357 100644
--- a/test/decl/protocol/conforms/fixit_stub_amiguity.swift
+++ b/test/decl/protocol/conforms/fixit_stub_amiguity.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %S/Inputs/fixit_stub_ambiguity_module.swift -module-name Ambiguous -emit-module -parse-as-library -o %t
 
-// RUN: %target-swift-frontend -typecheck %s -I %t -verify
+// RUN: %target-swift-frontend -typecheck %s -I %t -verify -verify-ignore-unrelated
 
 import Ambiguous
 
diff --git a/test/decl/protocol/conforms/fixit_stub_generic.swift b/test/decl/protocol/conforms/fixit_stub_generic.swift
new file mode 100644
index 0000000000000..b47ef8c65f6fa
--- /dev/null
+++ b/test/decl/protocol/conforms/fixit_stub_generic.swift
@@ -0,0 +1,13 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol P1 {
+  associatedtype A
+}
+
+protocol P2 {
+  func f<T>(_: T, _: T) // expected-note {{protocol requires function 'f' with type '<T> (T, T) -> ()'}}
+  func f<T: P1>(_: T, _: T.A) // expected-note {{protocol requires function 'f' with type '<T> (T, T.A) -> ()'}}
+}
+
+struct S: P2 {} // expected-error {{type 'S' does not conform to protocol 'P2'}}
+// expected-note@-1 {{add stubs for conformance}}
diff --git a/test/decl/protocol/conforms/objc_async.swift b/test/decl/protocol/conforms/objc_async.swift
index 4ae407b86de68..8c6c19bb3d8cb 100644
--- a/test/decl/protocol/conforms/objc_async.swift
+++ b/test/decl/protocol/conforms/objc_async.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules  -target %target-swift-5.1-abi-triple %s -verify -verify-ignore-unknown
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -I %S/Inputs/custom-modules  -target %target-swift-5.1-abi-triple %s -verify -verify-ignore-unrelated -verify-ignore-unknown
 
 // REQUIRES: objc_interop
 // REQUIRES: concurrency
diff --git a/test/decl/protocol/conforms/objc_renamed.swift b/test/decl/protocol/conforms/objc_renamed.swift
new file mode 100644
index 0000000000000..5dc3e65f340b1
--- /dev/null
+++ b/test/decl/protocol/conforms/objc_renamed.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated %s
+
+// REQUIRES: objc_interop
+
+import Foundation
+
+extension NSCouldConformToIndexable: @retroactive NSIndexable {
+}
+
+extension NSCouldConformToIndexable {
+  func testIndex(_ i: Int) {
+    _ = objectAtIndex(i) // expected-error {{'objectAtIndex' has been renamed to 'object(at:)'}}
+    _ = object(at: i)
+  }
+}
diff --git a/test/decl/protocol/conforms/placement.swift b/test/decl/protocol/conforms/placement.swift
index 955f8332a0277..34da6e172b6b8 100644
--- a/test/decl/protocol/conforms/placement.swift
+++ b/test/decl/protocol/conforms/placement.swift
@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend %S/Inputs/placement_module_A.swift -emit-module -parse-as-library -o %t
 // RUN: %target-swift-frontend -I %t %S/Inputs/placement_module_B.swift -emit-module -parse-as-library -o %t
 
-// RUN: %target-swift-frontend -typecheck -primary-file %s %S/Inputs/placement_2.swift -I %t -verify
+// RUN: %target-swift-frontend -typecheck -primary-file %s %S/Inputs/placement_2.swift -I %t -verify -verify-ignore-unrelated
 
 // Tests for the placement of conformances as well as conflicts
 // between conformances that come from different sources.
diff --git a/test/decl/protocol/conforms/redundant_conformance.swift b/test/decl/protocol/conforms/redundant_conformance.swift
index 41d8b1953f376..13ce00474c823 100644
--- a/test/decl/protocol/conforms/redundant_conformance.swift
+++ b/test/decl/protocol/conforms/redundant_conformance.swift
@@ -2,7 +2,7 @@
 
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/redundant_conformance_A.swift
 // RUN: %target-swift-frontend -emit-module -o %t -I %t %S/Inputs/redundant_conformance_B.swift
-// RUN: %target-typecheck-verify-swift -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t
 
 import redundant_conformance_A
 import redundant_conformance_B
diff --git a/test/decl/protocol/conforms/redundant_conformance_same_conditions.swift b/test/decl/protocol/conforms/redundant_conformance_same_conditions.swift
index c5c7502546bdd..c3f624aeece76 100644
--- a/test/decl/protocol/conforms/redundant_conformance_same_conditions.swift
+++ b/test/decl/protocol/conforms/redundant_conformance_same_conditions.swift
@@ -2,7 +2,7 @@
 
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/redundant_conformance_A.swift
 // RUN: %target-swift-frontend -emit-module -o %t -I %t %S/Inputs/redundant_conformance_B.swift
-// RUN: %target-typecheck-verify-swift -I %t
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t
 
 import redundant_conformance_A
 import redundant_conformance_B
diff --git a/test/decl/protocol/conforms/typed_throws.swift b/test/decl/protocol/conforms/typed_throws.swift
index 352312819c4f5..157b02ca42d9c 100644
--- a/test/decl/protocol/conforms/typed_throws.swift
+++ b/test/decl/protocol/conforms/typed_throws.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -parse-as-library
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -parse-as-library
 
 enum MyError: Error {
 case failed
@@ -62,7 +62,7 @@ struct S3: FailureAssociatedType {
 func testAssociatedTypes() {
   let _ = S1.Failure() // expected-error{{'S1.Failure' (aka 'MyError') cannot be constructed because it has no accessible initializers}}
   let _ = S2.Failure() // expected-error{{'S2.Failure' (aka 'any Error') cannot be constructed because it has no accessible initializers}}
-  let _: Int = S3.Failure() // expected-error{{cannot convert value of type 'S3.Failure' (aka 'Never') to specified type 'Int'}}
+  let _: Int = S3.Failure() // expected-error{{cannot convert value of type 'Never' to specified type 'Int'}}
   // expected-error@-1{{missing argument for parameter 'from' in call}}
 }
 
@@ -77,3 +77,17 @@ public protocol HasRethrowingMap: Sequence {
 }
 
 extension Array: HasRethrowingMap {}
+
+// rdar://149438520 -- incorrect handling of subtype relation between type parameter and Never
+protocol DependentThrowing {
+  associatedtype E: Error
+  func f() throws(E)
+}
+
+extension DependentThrowing {
+  func f() {}
+}
+
+struct DefaultDependentThrowing: DependentThrowing {
+  typealias E = Error
+}
\ No newline at end of file
diff --git a/test/decl/protocol/deserialized_witness_mismatch.swift b/test/decl/protocol/deserialized_witness_mismatch.swift
index 9a37b2d6b3488..6705156121807 100644
--- a/test/decl/protocol/deserialized_witness_mismatch.swift
+++ b/test/decl/protocol/deserialized_witness_mismatch.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %S/Inputs/deserialized_witness_mismatch_other.swift -emit-module-path %t/deserialized_witness_mismatch_other.swiftmodule
-// RUN: %target-swift-frontend -I %t/ %s -typecheck -verify
+// RUN: %target-swift-frontend -I %t/ %s -typecheck -verify -verify-ignore-unrelated
 
 // Deserialized computed properties don't have a PatternBindingDecl, so
 // make sure we don't expect to find one.
diff --git a/test/decl/protocol/existential_member_access/basic.swift b/test/decl/protocol/existential_member_access/basic.swift
index e5590a15347af..c9122f4de11d3 100644
--- a/test/decl/protocol/existential_member_access/basic.swift
+++ b/test/decl/protocol/existential_member_access/basic.swift
@@ -506,8 +506,6 @@ do {
     func invariant11() -> Struct<${type}>.InnerGeneric<Void>
     // https://github.com/apple/swift/issues/61934
     func invariant12() -> any Sequence<${type}>
-    // FIXME
-    // expected-error@+1 {{non-protocol, non-class type 'Sequence<${type}>' cannot be used within a protocol-constrained type}}
     func invariant13() -> any P & Sequence<${type}>
     func invariant14() -> (any Sequence<${type}>).Type
     func invariant15() -> any (P & Class<${type}>).Type
diff --git a/test/decl/protocol/existential_member_access/concrete.swift b/test/decl/protocol/existential_member_access/concrete.swift
index 1cd4e4247a136..22868aa804e85 100644
--- a/test/decl/protocol/existential_member_access/concrete.swift
+++ b/test/decl/protocol/existential_member_access/concrete.swift
@@ -166,7 +166,7 @@ do {
   // FIXME: Should GenericSignature::getConcreteType return the null type instead
   // of the error type here for Self.A, despite the broken conformance?
   let exist: any CompositionBrokenClassConformance_b & BadConformanceClass
-  exist.method(false) // expected-error {{type of expression is ambiguous without a type annotation}}
+  exist.method(false) // expected-error {{failed to produce diagnostic for expression}}
 }
 
 // https://github.com/swiftlang/swift/issues/65533
diff --git a/test/decl/protocol/existential_member_access/constraint_failure.swift b/test/decl/protocol/existential_member_access/constraint_failure.swift
index 76461f27b8f30..c3ed68e8aae73 100644
--- a/test/decl/protocol/existential_member_access/constraint_failure.swift
+++ b/test/decl/protocol/existential_member_access/constraint_failure.swift
@@ -76,7 +76,7 @@ do {
   let exist2: any UnfulfillableGenericRequirementsDerived2
 
   exist1.method4(false)
-  // expected-error@-1 {{instance method 'method4' requires that 'Bool' inherit from 'Class<Self.A>}}
+  // expected-error@-1 {{instance method 'method4' requires that 'Bool' inherit from 'Class<Bool>}}
   exist2.method4(false)
   // expected-error@-1 {{member 'method4' cannot be used on value of type 'any UnfulfillableGenericRequirementsDerived2'; consider using a generic constraint instead}}
   // expected-error@-2 {{instance method 'method4' requires that 'Bool' inherit from 'Class<Self.A>'}}
diff --git a/test/decl/protocol/fixits_missing_protocols_in_context.swift b/test/decl/protocol/fixits_missing_protocols_in_context.swift
index b0b13d05909be..8e995678286ed 100644
--- a/test/decl/protocol/fixits_missing_protocols_in_context.swift
+++ b/test/decl/protocol/fixits_missing_protocols_in_context.swift
@@ -13,7 +13,7 @@ class C {
   func assign() {
     p = self
     // expected-error@-1 {{cannot assign value of type 'C' to type '(any P)?'}}
-    // expected-note@-2 {{add missing conformance to 'P' to class 'C'}} {{-4:8-8=: P}} {{-4:10-10=\n    func method() {\n        <#code#>\n    \}\n\n    var property: Int\n}}
+    // expected-note@-2 {{add missing conformance to 'P' to class 'C'}} {{-4:8-8=: P}} {{-4:10-10=\n    func method() {\n        <#code#>\n    \}\n\n    let property: Int\n}}
   }
 }
 
@@ -25,7 +25,7 @@ class C1 {
   func assign() {
     p = self
     // expected-error@-1 {{cannot assign value of type 'C1' to type '(any P)?'}}
-    // expected-note@-2 {{add missing conformance to 'P' to class 'C1'}} {{-4:9-9=: P}} {{-4:11-11=\n    var property: Int\n}}
+    // expected-note@-2 {{add missing conformance to 'P' to class 'C1'}} {{-4:9-9=: P}} {{-4:11-11=\n    let property: Int\n}}
   }
 
   func method() {}
diff --git a/test/decl/protocol/objc_error_convention_conflict.swift b/test/decl/protocol/objc_error_convention_conflict.swift
index abe2c1eb62012..1610cadc1c762 100644
--- a/test/decl/protocol/objc_error_convention_conflict.swift
+++ b/test/decl/protocol/objc_error_convention_conflict.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify %s -import-objc-header %S/Inputs/objc_error_convention_conflict.h
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify -verify-ignore-unrelated %s -import-objc-header %S/Inputs/objc_error_convention_conflict.h
 // REQUIRES: objc_interop
 
 class CallerXYImpl: CallerX, CallerY {
diff --git a/test/decl/protocol/protocols.swift b/test/decl/protocol/protocols.swift
index e1bd80a016360..bc1c9d7c51312 100644
--- a/test/decl/protocol/protocols.swift
+++ b/test/decl/protocol/protocols.swift
@@ -111,10 +111,10 @@ struct DoesNotConform : Up {
 
 // Circular protocols
 
-protocol CircleMiddle : CircleStart { func circle_middle() }
-// expected-note@-1 2 {{protocol 'CircleMiddle' declared here}}
 protocol CircleStart : CircleEnd { func circle_start() } // expected-error 2 {{protocol 'CircleStart' refines itself}}
-protocol CircleEnd : CircleMiddle { func circle_end()} // expected-note 2 {{protocol 'CircleEnd' declared here}}
+protocol CircleMiddle : CircleStart { func circle_middle() }
+// expected-note@-1 2 {{through protocol 'CircleMiddle' declared here}}
+protocol CircleEnd : CircleMiddle { func circle_end()} // expected-note 2 {{through protocol 'CircleEnd' declared here}}
 
 protocol CircleEntry : CircleTrivial { }
 protocol CircleTrivial : CircleTrivial { } // expected-error {{protocol 'CircleTrivial' refines itself}}
@@ -412,7 +412,7 @@ class DoesntConformToObjCProtocol : ObjCProtocol {
 
 @objc protocol ObjCProtocolRefinement : ObjCProtocol { }
 
-@objc protocol ObjCNonObjCProtocolRefinement : NonObjCProtocol { } //expected-error{{@objc protocol 'ObjCNonObjCProtocolRefinement' cannot refine non-@objc protocol 'NonObjCProtocol'}}
+@objc protocol ObjCNonObjCProtocolRefinement : NonObjCProtocol { } //expected-error{{'@objc' protocol 'ObjCNonObjCProtocolRefinement' cannot refine non-'@objc' protocol 'NonObjCProtocol'}}
 
 
 // <rdar://problem/16079878>
diff --git a/test/decl/protocol/req/optional.swift b/test/decl/protocol/req/optional.swift
index ba512dd7a4e6d..0fd3d2be47a2a 100644
--- a/test/decl/protocol/req/optional.swift
+++ b/test/decl/protocol/req/optional.swift
@@ -216,7 +216,7 @@ optional class optErrorClass { // expected-error{{'optional' modifier cannot be
 }
 
 protocol optErrorProtocol {
-  optional func foo(_ x: Int) // expected-error{{'optional' can only be applied to members of an @objc protocol}}
+  optional func foo(_ x: Int) // expected-error{{'optional' can only be applied to members of an '@objc' protocol}}
 }
 
 @objc protocol optObjcAttributeProtocol {
diff --git a/test/decl/protocol/req/recursion.swift b/test/decl/protocol/req/recursion.swift
index 013f6f133add3..0581faa0d4de0 100644
--- a/test/decl/protocol/req/recursion.swift
+++ b/test/decl/protocol/req/recursion.swift
@@ -5,16 +5,14 @@ protocol SomeProtocol {
 }
 
 extension SomeProtocol where T == Optional<T> { }
-// expected-error@-1 {{cannot build rewrite system for generic signature; concrete nesting limit exceeded}}
+// expected-error@-1 {{cannot build rewrite system for generic signature; concrete type nesting limit exceeded}}
 // expected-note@-2 {{failed rewrite rule is τ_0_0.[SomeProtocol:T].[concrete: Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<Optional<τ_0_0.[SomeProtocol:T]>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>] => τ_0_0.[SomeProtocol:T]}}
 
 // rdar://problem/19840527
 
 class X<T> where T == X {
-// expected-error@-1 {{cannot build rewrite system for generic signature; concrete nesting limit exceeded}}
-// expected-note@-2 {{failed rewrite rule is τ_0_0.[concrete: X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<τ_0_0>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>] => τ_0_0}}
-// expected-error@-3 {{generic class 'X' has self-referential generic requirements}}
-    var type: T { return Swift.type(of: self) } // expected-error{{cannot convert return expression of type 'X<T>.Type' to return type 'T'}}
+// expected-error@-1 {{generic class 'X' has self-referential generic requirements}}
+    var type: T { return Swift.type(of: self) }
 }
 
 // FIXME: The "associated type 'Foo' is not a member type of 'Self'" diagnostic
diff --git a/test/decl/protocol/req/unavailable.swift b/test/decl/protocol/req/unavailable.swift
index 3cc1280668d9f..fa896d55c85d2 100644
--- a/test/decl/protocol/req/unavailable.swift
+++ b/test/decl/protocol/req/unavailable.swift
@@ -15,12 +15,12 @@ class Foo : Proto {
 // Reject protocols with 'unavailable' requirements
 // if a protocol is not marked @objc.
 protocol NonObjCProto {
-  @available(*,unavailable) // expected-error {{protocol members can only be marked unavailable in an @objc protocol}}
+  @available(*,unavailable) // expected-error {{protocol members can only be marked unavailable in an '@objc' protocol}}
   func bad() // expected-note {{protocol requires function 'bad()'}}
 
   func good()
 
-  @_spi_available(macOS, introduced: 10.9) // expected-warning {{protocol members can only be marked unavailable in an @objc protocol}}
+  @_spi_available(macOS, introduced: 10.9) // expected-warning {{protocol members can only be marked unavailable in an '@objc' protocol}}
   func kindaBad() // expected-note {{protocol requires function 'kindaBad()'}}
 }
 
diff --git a/test/decl/protocol/req/unsatisfiable.swift b/test/decl/protocol/req/unsatisfiable.swift
index a96e205642743..6b9709de6b4bc 100644
--- a/test/decl/protocol/req/unsatisfiable.swift
+++ b/test/decl/protocol/req/unsatisfiable.swift
@@ -97,3 +97,32 @@ class C7<T>: P7 { // expected-error {{type 'C7<T>' does not conform to protocol
 // expected-note@-1 {{add stubs for conformance}}
   typealias A = T
 }
+
+// This used to just crash.
+protocol LayoutConstraint {
+  associatedtype A
+
+  func f<T>(_: T) where A: AnyObject
+  // expected-error@-1 {{instance method requirement 'f' cannot add constraint 'Self.A: AnyObject' on 'Self'}}
+}
+
+protocol Q {
+  associatedtype A3
+}
+
+// We missed these cases originally.
+protocol ComplexDerivation {
+  associatedtype A1
+  associatedtype A2: Q
+
+  func bad1<B: Equatable>(_: B) where B == Self.A1
+  // expected-warning@-1 {{instance method requirement 'bad1' cannot add constraint 'Self.A1: Equatable' on 'Self'; this will be an error in a future Swift language mode}}
+
+  func bad2<B>(_: B) where A1 == [B]
+  // expected-warning@-1 {{instance method requirement 'bad2' cannot add constraint 'Self.A1 == [B]' on 'Self'; this will be an error in a future Swift language mode}}
+
+  func good<B>(_: B) where A2 == B  // This is fine
+
+  func bad3<B, C>(_: B, _: C) where A2 == B, B.A3 == [C]
+  // expected-warning@-1 {{instance method requirement 'bad3' cannot add constraint 'Self.A2.A3 == Array<C>' on 'Self'; this will be an error in a future Swift language mode}}
+}
diff --git a/test/decl/protocol/req/witness_fix_its.swift b/test/decl/protocol/req/witness_fix_its.swift
index 2b923ab040dd8..1148bbbf5eb5d 100644
--- a/test/decl/protocol/req/witness_fix_its.swift
+++ b/test/decl/protocol/req/witness_fix_its.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -o %t/OtherOS.swiftmodule -module-name OtherOS %S/Inputs/witness_fix_its_other_module.swift -parse-as-library
-// RUN: %target-typecheck-verify-swift -I %t/
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -I %t/
 
 prefix operator ^^^
 postfix operator ^^^^
diff --git a/test/decl/protocol/special/Actor.swift b/test/decl/protocol/special/Actor.swift
index 6e11f8628413c..b6a1298092e9f 100644
--- a/test/decl/protocol/special/Actor.swift
+++ b/test/decl/protocol/special/Actor.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift 
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated 
 // REQUIRES: concurrency
 
 // Synthesis of conformances for actors.
@@ -44,7 +44,7 @@ actor A7 {
 @available(SwiftStdlib 5.1, *)
 class C1: Actor {
   // expected-error@-1{{non-actor type 'C1' cannot conform to the 'Actor' protocol}}
-  // expected-warning@-2{{non-final class 'C1' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+  // expected-warning@-2{{non-final class 'C1' cannot conform to the 'Sendable' protocol}}
   nonisolated var unownedExecutor: UnownedSerialExecutor {
     fatalError("")
   }
@@ -53,7 +53,7 @@ class C1: Actor {
 @available(SwiftStdlib 5.1, *)
 class C2: Actor {
   // expected-error@-1{{non-actor type 'C2' cannot conform to the 'Actor' protocol}}
-// expected-warning@-2{{non-final class 'C2' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+  // expected-warning@-2{{non-final class 'C2' cannot conform to the 'Sendable' protocol}}
   // FIXME: this should be an isolation violation
   var unownedExecutor: UnownedSerialExecutor {
     fatalError("")
@@ -65,7 +65,7 @@ class C3: Actor {
   // expected-error@-1{{type 'C3' does not conform to protocol 'Actor'}}
   // expected-note@-2{{add stubs for conformance}}
   // expected-error@-3{{non-actor type 'C3' cannot conform to the 'Actor' protocol}}
-  // expected-warning@-4{{non-final class 'C3' cannot conform to 'Sendable'; use '@unchecked Sendable'}}
+  // expected-warning@-4{{non-final class 'C3' cannot conform to the 'Sendable' protocol}}
   nonisolated func enqueue(_ job: UnownedJob) { }
 }
 
diff --git a/test/decl/protocol/special/case_iterable/case_iterable_unsupported.swift b/test/decl/protocol/special/case_iterable/case_iterable_unsupported.swift
index f707e5017207c..ded431bc969d2 100644
--- a/test/decl/protocol/special/case_iterable/case_iterable_unsupported.swift
+++ b/test/decl/protocol/special/case_iterable/case_iterable_unsupported.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify -primary-file %s %S/../Inputs/case_iterable_other.swift -verify-additional-prefix unsupported- -verify-ignore-unknown
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -primary-file %s %S/../Inputs/case_iterable_other.swift -verify-additional-prefix unsupported- -verify-ignore-unknown
 
 extension FromOtherFile: CaseIterable {} // expected-error {{extension outside of file declaring enum 'FromOtherFile' prevents automatic synthesis of 'allCases' for protocol 'CaseIterable'}} expected-note {{add stubs for conformance}}
 
diff --git a/test/decl/protocol/special/coding/class_codable_codingkeys_typealias.swift b/test/decl/protocol/special/coding/class_codable_codingkeys_typealias.swift
index c62afac107629..17476481e555e 100644
--- a/test/decl/protocol/special/coding/class_codable_codingkeys_typealias.swift
+++ b/test/decl/protocol/special/coding/class_codable_codingkeys_typealias.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Simple classes with all Codable properties whose CodingKeys come from a
 // typealias should get derived conformance to Codable.
diff --git a/test/decl/protocol/special/coding/class_codable_computed_vars.swift b/test/decl/protocol/special/coding/class_codable_computed_vars.swift
index 1f4088be122ce..0962f87f9d6d9 100644
--- a/test/decl/protocol/special/coding/class_codable_computed_vars.swift
+++ b/test/decl/protocol/special/coding/class_codable_computed_vars.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Classes with computed members should get synthesized conformance to Codable,
 // but their lazy and computed members should be skipped as part of the
diff --git a/test/decl/protocol/special/coding/class_codable_default_initializer.swift b/test/decl/protocol/special/coding/class_codable_default_initializer.swift
index 017aaf726f349..43892518b50c7 100644
--- a/test/decl/protocol/special/coding/class_codable_default_initializer.swift
+++ b/test/decl/protocol/special/coding/class_codable_default_initializer.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // A class with no initializers (which has non-initialized properties so a
 // default constructor can be synthesized) should produce an error.
diff --git a/test/decl/protocol/special/coding/class_codable_excluded_optional_properties.swift b/test/decl/protocol/special/coding/class_codable_excluded_optional_properties.swift
index 1b2d1ccb5f6a5..3aa08cf0739da 100644
--- a/test/decl/protocol/special/coding/class_codable_excluded_optional_properties.swift
+++ b/test/decl/protocol/special/coding/class_codable_excluded_optional_properties.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 class ClassWithNonExcludedLetMembers : Codable { // expected-error {{class 'ClassWithNonExcludedLetMembers' has no initializers}}
     // expected-error@-1 {{type 'ClassWithNonExcludedLetMembers' does not conform to protocol 'Decodable'}}
diff --git a/test/decl/protocol/special/coding/class_codable_failure_diagnostics.swift b/test/decl/protocol/special/coding/class_codable_failure_diagnostics.swift
index e06724325099c..8fb36a5fd8a97 100644
--- a/test/decl/protocol/special/coding/class_codable_failure_diagnostics.swift
+++ b/test/decl/protocol/special/coding/class_codable_failure_diagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -swift-version 4 %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -swift-version 4 %s -verify -verify-ignore-unrelated
 
 // Codable class with non-Codable property.
 class C1 : Codable {
diff --git a/test/decl/protocol/special/coding/class_codable_inheritance.swift b/test/decl/protocol/special/coding/class_codable_inheritance.swift
index f20702bb7f16e..f07ce4432986d 100644
--- a/test/decl/protocol/special/coding/class_codable_inheritance.swift
+++ b/test/decl/protocol/special/coding/class_codable_inheritance.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 class SimpleClass : Codable {
   var x: Int = 1
diff --git a/test/decl/protocol/special/coding/class_codable_inheritance_diagnostics.swift b/test/decl/protocol/special/coding/class_codable_inheritance_diagnostics.swift
index aeac7d871e470..042f77ee907c9 100644
--- a/test/decl/protocol/special/coding/class_codable_inheritance_diagnostics.swift
+++ b/test/decl/protocol/special/coding/class_codable_inheritance_diagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Non-Decodable superclasses of synthesized Decodable classes must implement
 // init().
diff --git a/test/decl/protocol/special/coding/class_codable_invalid_codingkeys.swift b/test/decl/protocol/special/coding/class_codable_invalid_codingkeys.swift
index a4ce3323a8785..8187c4dfea24c 100644
--- a/test/decl/protocol/special/coding/class_codable_invalid_codingkeys.swift
+++ b/test/decl/protocol/special/coding/class_codable_invalid_codingkeys.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Classes with a CodingKeys entity which is not a type should not derive
 // conformance.
diff --git a/test/decl/protocol/special/coding/class_codable_member_type_lookup.swift b/test/decl/protocol/special/coding/class_codable_member_type_lookup.swift
index a5aff44830681..43653e6ca641b 100644
--- a/test/decl/protocol/special/coding/class_codable_member_type_lookup.swift
+++ b/test/decl/protocol/special/coding/class_codable_member_type_lookup.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -package-name myPkg
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -package-name myPkg
 
 // A top-level CodingKeys type to fall back to in lookups below.
 public enum CodingKeys : String, CodingKey {
diff --git a/test/decl/protocol/special/coding/class_codable_non_strong_vars.swift b/test/decl/protocol/special/coding/class_codable_non_strong_vars.swift
index cfe2497a2322e..e0a0da1578e59 100644
--- a/test/decl/protocol/special/coding/class_codable_non_strong_vars.swift
+++ b/test/decl/protocol/special/coding/class_codable_non_strong_vars.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Classes with Codable properties (with non-strong ownership) should get
 // derived conformance to Codable.
diff --git a/test/decl/protocol/special/coding/class_codable_nonconforming_property.swift b/test/decl/protocol/special/coding/class_codable_nonconforming_property.swift
index 34ee37d3e57e3..1dca870132a43 100644
--- a/test/decl/protocol/special/coding/class_codable_nonconforming_property.swift
+++ b/test/decl/protocol/special/coding/class_codable_nonconforming_property.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 struct NonCodable : Hashable {
     func hash(into hasher: inout Hasher) {}
diff --git a/test/decl/protocol/special/coding/class_codable_simple.swift b/test/decl/protocol/special/coding/class_codable_simple.swift
index b3404223592b1..6c98c1f65c3e2 100644
--- a/test/decl/protocol/special/coding/class_codable_simple.swift
+++ b/test/decl/protocol/special/coding/class_codable_simple.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Simple classes with all Codable properties should get derived conformance to
 // Codable.
diff --git a/test/decl/protocol/special/coding/class_codable_simple_conditional.swift b/test/decl/protocol/special/coding/class_codable_simple_conditional.swift
index 6dd447e6508d5..a3fb8541aedef 100644
--- a/test/decl/protocol/special/coding/class_codable_simple_conditional.swift
+++ b/test/decl/protocol/special/coding/class_codable_simple_conditional.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 class Conditional<T> {
   var x: T
diff --git a/test/decl/protocol/special/coding/class_codable_simple_conditional_final.swift b/test/decl/protocol/special/coding/class_codable_simple_conditional_final.swift
index e41e64271d82b..210e067c3400a 100644
--- a/test/decl/protocol/special/coding/class_codable_simple_conditional_final.swift
+++ b/test/decl/protocol/special/coding/class_codable_simple_conditional_final.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 final class Conditional<T> {
   var x: T
diff --git a/test/decl/protocol/special/coding/class_codable_simple_conditional_final_separate.swift b/test/decl/protocol/special/coding/class_codable_simple_conditional_final_separate.swift
index fec5d2a8277c1..bd3057996da01 100644
--- a/test/decl/protocol/special/coding/class_codable_simple_conditional_final_separate.swift
+++ b/test/decl/protocol/special/coding/class_codable_simple_conditional_final_separate.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 final class Conditional<T> {
   var x: T
diff --git a/test/decl/protocol/special/coding/class_codable_simple_conditional_separate.swift b/test/decl/protocol/special/coding/class_codable_simple_conditional_separate.swift
index 0033a58b734a8..4fb99e7921c1b 100644
--- a/test/decl/protocol/special/coding/class_codable_simple_conditional_separate.swift
+++ b/test/decl/protocol/special/coding/class_codable_simple_conditional_separate.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 class Conditional<T> {
   var x: T
diff --git a/test/decl/protocol/special/coding/class_codable_simple_extension.swift b/test/decl/protocol/special/coding/class_codable_simple_extension.swift
index 90b21c3331f00..2aeb8bc991c53 100644
--- a/test/decl/protocol/special/coding/class_codable_simple_extension.swift
+++ b/test/decl/protocol/special/coding/class_codable_simple_extension.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 // Non-final classes where Codable conformance is added in extensions should
 // only be able to derive conformance for Encodable.
diff --git a/test/decl/protocol/special/coding/class_codable_simple_extension_final.swift b/test/decl/protocol/special/coding/class_codable_simple_extension_final.swift
index c6b323f9fd462..e6eb29bca72dd 100644
--- a/test/decl/protocol/special/coding/class_codable_simple_extension_final.swift
+++ b/test/decl/protocol/special/coding/class_codable_simple_extension_final.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 // Simple final classes where Codable conformance is added in extensions should
 // be able to derive conformance for both Codable protocols.
diff --git a/test/decl/protocol/special/coding/class_codable_simple_multi.swift b/test/decl/protocol/special/coding/class_codable_simple_multi.swift
index 1c6245e1d41d5..61aaf4cc616c0 100644
--- a/test/decl/protocol/special/coding/class_codable_simple_multi.swift
+++ b/test/decl/protocol/special/coding/class_codable_simple_multi.swift
@@ -1,2 +1,2 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown %S/Inputs/class_codable_simple_multi1.swift %S/Inputs/class_codable_simple_multi2.swift
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown %S/Inputs/class_codable_simple_multi2.swift %S/Inputs/class_codable_simple_multi1.swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown %S/Inputs/class_codable_simple_multi1.swift %S/Inputs/class_codable_simple_multi2.swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown %S/Inputs/class_codable_simple_multi2.swift %S/Inputs/class_codable_simple_multi1.swift
diff --git a/test/decl/protocol/special/coding/codable_parameter_pack.swift b/test/decl/protocol/special/coding/codable_parameter_pack.swift
new file mode 100644
index 0000000000000..310e133328b56
--- /dev/null
+++ b/test/decl/protocol/special/coding/codable_parameter_pack.swift
@@ -0,0 +1,7 @@
+// RUN: %target-typecheck-verify-swift -target %target-swift-5.9-abi-triple
+
+// We should accept this:
+
+public struct HasPack<each T>: Codable {
+  var x: String?
+}
diff --git a/test/decl/protocol/special/coding/enum_codable_case_identifier_overloads.swift b/test/decl/protocol/special/coding/enum_codable_case_identifier_overloads.swift
index 3007f89c4c00e..91192900cc9ed 100644
--- a/test/decl/protocol/special/coding/enum_codable_case_identifier_overloads.swift
+++ b/test/decl/protocol/special/coding/enum_codable_case_identifier_overloads.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Simple enums with all Codable parameters whose CodingKeys come from a
 // typealias should get derived conformance to Codable.
diff --git a/test/decl/protocol/special/coding/enum_codable_codingkeys_typealias.swift b/test/decl/protocol/special/coding/enum_codable_codingkeys_typealias.swift
index 17b53610f3fe6..86ba2445d3bb5 100644
--- a/test/decl/protocol/special/coding/enum_codable_codingkeys_typealias.swift
+++ b/test/decl/protocol/special/coding/enum_codable_codingkeys_typealias.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Simple enums with all Codable parameters whose CodingKeys come from a
 // typealias should get derived conformance to Codable.
diff --git a/test/decl/protocol/special/coding/enum_codable_conflicting_parameter_identifier.swift b/test/decl/protocol/special/coding/enum_codable_conflicting_parameter_identifier.swift
index 43e71ea7ef80c..efaf70573b894 100644
--- a/test/decl/protocol/special/coding/enum_codable_conflicting_parameter_identifier.swift
+++ b/test/decl/protocol/special/coding/enum_codable_conflicting_parameter_identifier.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 enum Duplicate : Codable { // expected-error {{type 'Duplicate' does not conform to protocol 'Decodable'}}
   // expected-error@-1 {{type 'Duplicate' does not conform to protocol 'Encodable'}}
diff --git a/test/decl/protocol/special/coding/enum_codable_excluded_optional_properties.swift b/test/decl/protocol/special/coding/enum_codable_excluded_optional_properties.swift
index d308bc7306278..6fd719067c24f 100644
--- a/test/decl/protocol/special/coding/enum_codable_excluded_optional_properties.swift
+++ b/test/decl/protocol/special/coding/enum_codable_excluded_optional_properties.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 enum EnumWithNonExcludedOptionalParameters : Codable { // expected-error {{type 'EnumWithNonExcludedOptionalParameters' does not conform to protocol 'Decodable'}}
     // expected-error@-1 {{type 'EnumWithNonExcludedOptionalParameters' does not conform to protocol 'Encodable'}}
diff --git a/test/decl/protocol/special/coding/enum_codable_failure_diagnostics.swift b/test/decl/protocol/special/coding/enum_codable_failure_diagnostics.swift
index 6a4435c742cfb..d107c60a7e393 100644
--- a/test/decl/protocol/special/coding/enum_codable_failure_diagnostics.swift
+++ b/test/decl/protocol/special/coding/enum_codable_failure_diagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -swift-version 4 %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -swift-version 4 %s -verify -verify-ignore-unrelated
 
 // Codable enum with non-Codable parameter.
 enum E1 : Codable {
diff --git a/test/decl/protocol/special/coding/enum_codable_invalid_codingkeys.swift b/test/decl/protocol/special/coding/enum_codable_invalid_codingkeys.swift
index 656301d860495..4c0745b27f5eb 100644
--- a/test/decl/protocol/special/coding/enum_codable_invalid_codingkeys.swift
+++ b/test/decl/protocol/special/coding/enum_codable_invalid_codingkeys.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Enums with a CodingKeys entity which is not a type should not derive
 // conformance.
diff --git a/test/decl/protocol/special/coding/enum_codable_nonconforming_property.swift b/test/decl/protocol/special/coding/enum_codable_nonconforming_property.swift
index ef3a55befdd9b..2619cdefc13a5 100644
--- a/test/decl/protocol/special/coding/enum_codable_nonconforming_property.swift
+++ b/test/decl/protocol/special/coding/enum_codable_nonconforming_property.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 enum NonCodable : Hashable {
     func hash(into hasher: inout Hasher) {}
diff --git a/test/decl/protocol/special/coding/enum_codable_simple.swift b/test/decl/protocol/special/coding/enum_codable_simple.swift
index 39a655020a0c3..1158d9bc4c263 100644
--- a/test/decl/protocol/special/coding/enum_codable_simple.swift
+++ b/test/decl/protocol/special/coding/enum_codable_simple.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Simple enums with all Codable parameters should get derived conformance to
 // Codable.
diff --git a/test/decl/protocol/special/coding/enum_codable_simple_conditional.swift b/test/decl/protocol/special/coding/enum_codable_simple_conditional.swift
index bb8af6d96e4a0..e5b9383f39416 100644
--- a/test/decl/protocol/special/coding/enum_codable_simple_conditional.swift
+++ b/test/decl/protocol/special/coding/enum_codable_simple_conditional.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 enum Conditional<T> {
   case a(x: T, y: T?)
diff --git a/test/decl/protocol/special/coding/enum_codable_simple_conditional_separate.swift b/test/decl/protocol/special/coding/enum_codable_simple_conditional_separate.swift
index 4d7cf1470b8c3..7b6d5abbc153d 100644
--- a/test/decl/protocol/special/coding/enum_codable_simple_conditional_separate.swift
+++ b/test/decl/protocol/special/coding/enum_codable_simple_conditional_separate.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 enum Conditional<T> {
   case a(x: T, y: T?)
diff --git a/test/decl/protocol/special/coding/enum_codable_simple_extension.swift b/test/decl/protocol/special/coding/enum_codable_simple_extension.swift
index 66d4d3ae82a2d..9930908725217 100644
--- a/test/decl/protocol/special/coding/enum_codable_simple_extension.swift
+++ b/test/decl/protocol/special/coding/enum_codable_simple_extension.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 // Simple enums where Codable conformance is added in extensions should derive
 // conformance.
diff --git a/test/decl/protocol/special/coding/enum_codable_simple_extension_flipped.swift b/test/decl/protocol/special/coding/enum_codable_simple_extension_flipped.swift
index 2c6fcb0793a39..d8e73537cebd9 100644
--- a/test/decl/protocol/special/coding/enum_codable_simple_extension_flipped.swift
+++ b/test/decl/protocol/special/coding/enum_codable_simple_extension_flipped.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 // Simple enums where Codable conformance is added in extensions should derive
 // conformance, no matter which order the extension and type occur in.
diff --git a/test/decl/protocol/special/coding/enum_codable_simple_multi.swift b/test/decl/protocol/special/coding/enum_codable_simple_multi.swift
index 457c41d332018..71fb7ea5a3fd8 100644
--- a/test/decl/protocol/special/coding/enum_codable_simple_multi.swift
+++ b/test/decl/protocol/special/coding/enum_codable_simple_multi.swift
@@ -1,2 +1,2 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown %S/Inputs/enum_codable_simple_multi1.swift %S/Inputs/enum_codable_simple_multi2.swift
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown %S/Inputs/enum_codable_simple_multi2.swift %S/Inputs/enum_codable_simple_multi1.swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown %S/Inputs/enum_codable_simple_multi1.swift %S/Inputs/enum_codable_simple_multi2.swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown %S/Inputs/enum_codable_simple_multi2.swift %S/Inputs/enum_codable_simple_multi1.swift
diff --git a/test/decl/protocol/special/coding/enum_coding_key.swift b/test/decl/protocol/special/coding/enum_coding_key.swift
index 74163dbafea33..b5bb4bf9c5037 100644
--- a/test/decl/protocol/special/coding/enum_coding_key.swift
+++ b/test/decl/protocol/special/coding/enum_coding_key.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Enums with no raw type conforming to CodingKey should get implicit derived
 // conformance of methods.
diff --git a/test/decl/protocol/special/coding/iuo_crash.swift b/test/decl/protocol/special/coding/iuo_crash.swift
index 63b3a61143d41..f1d2ea1be7e26 100644
--- a/test/decl/protocol/special/coding/iuo_crash.swift
+++ b/test/decl/protocol/special/coding/iuo_crash.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Crash due to codable synthesis with implicitly unwrapped optionals of
 // ill-formed types.
diff --git a/test/decl/protocol/special/coding/property_wrappers_codable.swift b/test/decl/protocol/special/coding/property_wrappers_codable.swift
index dcd821761e9c5..8bc58dd6fe61c 100644
--- a/test/decl/protocol/special/coding/property_wrappers_codable.swift
+++ b/test/decl/protocol/special/coding/property_wrappers_codable.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 @propertyWrapper
 struct Wrapper<T: Codable> {
diff --git a/test/decl/protocol/special/coding/struct_codable_codingkeys_typealias.swift b/test/decl/protocol/special/coding/struct_codable_codingkeys_typealias.swift
index ab298dff67f3f..ce67ed88fa1ed 100644
--- a/test/decl/protocol/special/coding/struct_codable_codingkeys_typealias.swift
+++ b/test/decl/protocol/special/coding/struct_codable_codingkeys_typealias.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Simple structs with all Codable properties whose CodingKeys come from a
 // typealias should get derived conformance to Codable.
diff --git a/test/decl/protocol/special/coding/struct_codable_computed_vars.swift b/test/decl/protocol/special/coding/struct_codable_computed_vars.swift
index 054c7d77f9fb1..11480cfc58096 100644
--- a/test/decl/protocol/special/coding/struct_codable_computed_vars.swift
+++ b/test/decl/protocol/special/coding/struct_codable_computed_vars.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Structs with computed members should get synthesized conformance to Codable,
 // but their lazy and computed members should be skipped as part of the
diff --git a/test/decl/protocol/special/coding/struct_codable_excluded_optional_properties.swift b/test/decl/protocol/special/coding/struct_codable_excluded_optional_properties.swift
index 84e9b9c3022ec..f8f7e93a34374 100644
--- a/test/decl/protocol/special/coding/struct_codable_excluded_optional_properties.swift
+++ b/test/decl/protocol/special/coding/struct_codable_excluded_optional_properties.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 struct StructWithNonExcludedLetMembers : Codable { // expected-error {{type 'StructWithNonExcludedLetMembers' does not conform to protocol 'Decodable'}}
     // expected-error@-1 {{type 'StructWithNonExcludedLetMembers' does not conform to protocol 'Encodable'}}
diff --git a/test/decl/protocol/special/coding/struct_codable_failure_diagnostics.swift b/test/decl/protocol/special/coding/struct_codable_failure_diagnostics.swift
index 4928fb44ecc68..7574a1f3d8a93 100644
--- a/test/decl/protocol/special/coding/struct_codable_failure_diagnostics.swift
+++ b/test/decl/protocol/special/coding/struct_codable_failure_diagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -swift-version 4 %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library -swift-version 4 %s -verify -verify-ignore-unrelated
 
 // Codable struct with non-Codable property.
 struct S1 : Codable {
diff --git a/test/decl/protocol/special/coding/struct_codable_invalid_codingkeys.swift b/test/decl/protocol/special/coding/struct_codable_invalid_codingkeys.swift
index 13f1777ce52f5..9718721dff8d2 100644
--- a/test/decl/protocol/special/coding/struct_codable_invalid_codingkeys.swift
+++ b/test/decl/protocol/special/coding/struct_codable_invalid_codingkeys.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Structs with a CodingKeys entity which is not a type should not derive
 // conformance.
diff --git a/test/decl/protocol/special/coding/struct_codable_member_type_lookup.swift b/test/decl/protocol/special/coding/struct_codable_member_type_lookup.swift
index e55e9747c1376..c1170c9b6da54 100644
--- a/test/decl/protocol/special/coding/struct_codable_member_type_lookup.swift
+++ b/test/decl/protocol/special/coding/struct_codable_member_type_lookup.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -package-name myPkg
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -package-name myPkg
 
 // A top-level CodingKeys type to fall back to in lookups below.
 public enum CodingKeys : String, CodingKey {
diff --git a/test/decl/protocol/special/coding/struct_codable_non_strong_vars.swift b/test/decl/protocol/special/coding/struct_codable_non_strong_vars.swift
index 2d02f4a63c5f6..40614d204c90d 100644
--- a/test/decl/protocol/special/coding/struct_codable_non_strong_vars.swift
+++ b/test/decl/protocol/special/coding/struct_codable_non_strong_vars.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Structs with Codable properties (with non-strong ownership) should get
 // derived conformance to Codable.
diff --git a/test/decl/protocol/special/coding/struct_codable_nonconforming_property.swift b/test/decl/protocol/special/coding/struct_codable_nonconforming_property.swift
index 934d182b66a76..31366c3575c56 100644
--- a/test/decl/protocol/special/coding/struct_codable_nonconforming_property.swift
+++ b/test/decl/protocol/special/coding/struct_codable_nonconforming_property.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 struct NonCodable : Hashable {
     func hash(into hasher: inout Hasher) {}
diff --git a/test/decl/protocol/special/coding/struct_codable_simple.swift b/test/decl/protocol/special/coding/struct_codable_simple.swift
index 13b835fd82efa..6b7252e8954a0 100644
--- a/test/decl/protocol/special/coding/struct_codable_simple.swift
+++ b/test/decl/protocol/special/coding/struct_codable_simple.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Simple structs with all Codable properties should get derived conformance to
 // Codable.
diff --git a/test/decl/protocol/special/coding/struct_codable_simple_conditional.swift b/test/decl/protocol/special/coding/struct_codable_simple_conditional.swift
index 836c8dcb73897..90ba5f0796db2 100644
--- a/test/decl/protocol/special/coding/struct_codable_simple_conditional.swift
+++ b/test/decl/protocol/special/coding/struct_codable_simple_conditional.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 struct Conditional<T> {
   var x: T
diff --git a/test/decl/protocol/special/coding/struct_codable_simple_conditional_separate.swift b/test/decl/protocol/special/coding/struct_codable_simple_conditional_separate.swift
index 40b2f3e0d225f..f5efa13064f2e 100644
--- a/test/decl/protocol/special/coding/struct_codable_simple_conditional_separate.swift
+++ b/test/decl/protocol/special/coding/struct_codable_simple_conditional_separate.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 struct Conditional<T> {
   var x: T
diff --git a/test/decl/protocol/special/coding/struct_codable_simple_extension.swift b/test/decl/protocol/special/coding/struct_codable_simple_extension.swift
index 89923f2db3cf0..0631a91d21d15 100644
--- a/test/decl/protocol/special/coding/struct_codable_simple_extension.swift
+++ b/test/decl/protocol/special/coding/struct_codable_simple_extension.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 // Simple structs where Codable conformance is added in extensions should derive
 // conformance.
diff --git a/test/decl/protocol/special/coding/struct_codable_simple_extension_flipped.swift b/test/decl/protocol/special/coding/struct_codable_simple_extension_flipped.swift
index c1000f7bac836..9bda11057d2a7 100644
--- a/test/decl/protocol/special/coding/struct_codable_simple_extension_flipped.swift
+++ b/test/decl/protocol/special/coding/struct_codable_simple_extension_flipped.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown -swift-version 4
 
 // Simple structs where Codable conformance is added in extensions should derive
 // conformance, no matter which order the extension and type occur in.
diff --git a/test/decl/protocol/special/coding/struct_codable_simple_multi.swift b/test/decl/protocol/special/coding/struct_codable_simple_multi.swift
index 0f6c47cfa0ae0..d2d775cdd0bc0 100644
--- a/test/decl/protocol/special/coding/struct_codable_simple_multi.swift
+++ b/test/decl/protocol/special/coding/struct_codable_simple_multi.swift
@@ -1,2 +1,2 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown %S/Inputs/struct_codable_simple_multi1.swift %S/Inputs/struct_codable_simple_multi2.swift
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown %S/Inputs/struct_codable_simple_multi2.swift %S/Inputs/struct_codable_simple_multi1.swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown %S/Inputs/struct_codable_simple_multi1.swift %S/Inputs/struct_codable_simple_multi2.swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown %S/Inputs/struct_codable_simple_multi2.swift %S/Inputs/struct_codable_simple_multi1.swift
diff --git a/test/decl/protocol/special/comparable/comparable_unsupported.swift b/test/decl/protocol/special/comparable/comparable_unsupported.swift
index bb2b39994775c..e8d9a2da9f8aa 100644
--- a/test/decl/protocol/special/comparable/comparable_unsupported.swift
+++ b/test/decl/protocol/special/comparable/comparable_unsupported.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 // Automatic synthesis of Comparable is only supported for enums for now.
 
diff --git a/test/decl/typealias/dependent_types.swift b/test/decl/typealias/dependent_types.swift
index a59e1809fe719..40b72e37bb96d 100644
--- a/test/decl/typealias/dependent_types.swift
+++ b/test/decl/typealias/dependent_types.swift
@@ -23,7 +23,7 @@ struct X1<T> : P1 {
   }
 }
 
-struct GenericStruct<T> { // expected-note 3{{generic type 'GenericStruct' declared here}}
+struct GenericStruct<T> { // expected-note 3{{generic struct 'GenericStruct' declared here}}
   typealias Alias = T
   typealias MetaAlias = T.Type
 
@@ -65,6 +65,7 @@ let _: GenericStruct.ReferencesConcrete = foo()
 
 class SuperG<T, U> {
   typealias Composed = (T, U)
+  typealias Concrete = Int
 }
 
 class SubG<T> : SuperG<T, T> { }
@@ -74,3 +75,16 @@ typealias SubGX<T> = SubG<T?>
 func checkSugar(gs: SubGX<Int>.Composed) {
   let i4: Int = gs // expected-error{{cannot convert value of type 'SubGX<Int>.Composed' (aka '(Optional<Int>, Optional<Int>)') to specified type 'Int'}}
 }
+
+// https://github.com/swiftlang/swift/issues/82160
+
+let x1: SuperG.Concrete = 123
+let x2: SubG.Concrete = 123
+
+func f1() -> SuperG.Concrete {
+  return 123
+}
+
+func f2() -> SubG.Concrete {
+  return 123
+}
\ No newline at end of file
diff --git a/test/decl/typealias/generic.swift b/test/decl/typealias/generic.swift
index 52d0cfb20bcb6..082a22f39f3fb 100644
--- a/test/decl/typealias/generic.swift
+++ b/test/decl/typealias/generic.swift
@@ -1,6 +1,6 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
-struct MyType<TyA, TyB> { // expected-note {{generic type 'MyType' declared here}}
+struct MyType<TyA, TyB> { // expected-note {{generic struct 'MyType' declared here}}
   // expected-note @-1 {{arguments to generic parameter 'TyB' ('S' and 'Int') are expected to be equal}}
 
   var a : TyA, b : TyB
@@ -71,7 +71,7 @@ func f() {
 }
 
 
-typealias A<T1, T2> = MyType<T2, T1>  // expected-note {{generic type 'A' declared here}}
+typealias A<T1, T2> = MyType<T2, T1>  // expected-note {{generic type alias 'A' declared here}}
 
 typealias B<T1> = MyType<T1, T1>
 
@@ -80,7 +80,7 @@ typealias C<T> = MyType<String, T>
 // Type aliases with unused generic params.
 typealias D<T1, T2, T3> = MyType<T2, T1>  // expected-note 3 {{'T3' declared as parameter to type 'D'}}
 
-typealias E<T1, T2> = Int  // expected-note {{generic type 'E' declared here}}
+typealias E<T1, T2> = Int  // expected-note {{generic type alias 'E' declared here}}
 // expected-note@-1 {{'T1' declared as parameter to type 'E'}}
 // expected-note@-2 {{'T2' declared as parameter to type 'E'}}
 
@@ -178,7 +178,7 @@ class GenericClass<T> {
   }
 
   func testCaptureInvalid1<S>(s: S, t: T) -> TA<Int> {
-    return TA<S>(a: t, b: s) // expected-error {{cannot convert return expression of type 'GenericClass<T>.TA<S>' (aka 'MyType<T, S>') to return type 'GenericClass<T>.TA<Int>' (aka 'MyType<T, Int>')}}
+    return TA<S>(a: t, b: s) // expected-error {{cannot convert return expression of type 'MyType<T, S>' to return type 'GenericClass<T>.TA<Int>' (aka 'MyType<T, Int>')}}
   }
 
   func testCaptureInvalid2<S>(s: Int, t: T) -> TA<S> {
@@ -356,7 +356,7 @@ extension Id {} // expected-error {{non-nominal type 'Id' cannot be extended}}
 
 class OuterGeneric<T> {
   typealias Alias<U> = AnotherGeneric<U>
-  // expected-note@-1 {{generic type 'Alias' declared here}}
+  // expected-note@-1 {{generic type alias 'Alias' declared here}}
   class InnerNonGeneric : Alias {}
   // expected-error@-1 {{reference to generic type 'OuterGeneric<T>.Alias' requires arguments in <...>}}
 }
@@ -465,3 +465,19 @@ func testSugar(_ gx: GX<Int>, _ gy: GX<Int>.GY<Double>, gz: GX<Int>.GY<Double>.E
   let i2: Int = gy  // expected-error{{cannot convert value of type 'GX<Int>.GY<Double>' (aka 'Array<Double>') to specified type 'Int'}}
   let i3: Int = gz // expected-error{{cannot convert value of type 'GX<Int>.GY<Double>.Element' (aka 'Double') to specified type 'Int'}}
 }
+
+func testLocalRequirementInference<T>(_ x: T, y: Int, s: S) {
+  typealias X<U: P> = (T, U) where T == U.A
+  func foo<V>(_ x: X<V>) {} // expected-note {{where 'V' = 'Int'}} expected-note {{where 'T' = 'T', 'V.A' = 'S.A' (aka 'Float')}}
+  foo((x, y)) // expected-error {{local function 'foo' requires that 'Int' conform to 'P'}}
+  foo((x, s)) // expected-error {{local function 'foo' requires the types 'T' and 'S.A' (aka 'Float') be equivalent}}
+}
+
+struct TestNestedRequirementInference<T> {
+  typealias X<U: P> = (T, U) where T == U.A
+  func foo<V>(_ x: X<V>) {} // expected-note {{where 'V' = 'Int'}} expected-note {{where 'T' = 'T', 'V.A' = 'S.A' (aka 'Float')}}
+  func bar(_ x: T, y: Int, s: S) {
+    foo((x, y)) // expected-error {{instance method 'foo' requires that 'Int' conform to 'P'}}
+    foo((x, s)) // expected-error {{instance method 'foo' requires the types 'T' and 'S.A' (aka 'Float') be equivalent}}
+  }
+}
diff --git a/test/decl/var/NSCopying.swift b/test/decl/var/NSCopying.swift
index 0adfd7033ff73..b7fedaa2080ea 100644
--- a/test/decl/var/NSCopying.swift
+++ b/test/decl/var/NSCopying.swift
@@ -11,12 +11,12 @@ class CopyableClass : NSCopying {
   }
 }
 
-@NSCopying  // expected-error {{@NSCopying may only be used on 'var' declarations}}}}
+@NSCopying  // expected-error {{@NSCopying may only be used on 'var' declarations}}
 func copyFunction() {}
 
 @NSCopying   // expected-error {{@NSCopying may only be used on 'var' declarations}}
 struct CopyingStruct  {
-  @NSCopying var x : CopyableClass   // expected-error {{@NSCopying may only be used on properties in classes}}
+  @NSCopying var x : CopyableClass   // expected-error {{'@NSCopying' may only be used on properties in classes}}
 }
 
 class CopyingClassTest {
@@ -27,11 +27,11 @@ class CopyingClassTest {
   @NSCopying weak var p1w : CopyableClass?
 
   // These are not.
-  @NSCopying let invalidLet : CopyableClass   // expected-error {{@NSCopying requires property to be mutable}}
-  @NSCopying var computed : CopyableClass { get {} set {} }  // expected-error {{@NSCopying is only valid on stored properties}}
+  @NSCopying let invalidLet : CopyableClass   // expected-error {{'@NSCopying' requires property to be mutable}}
+  @NSCopying var computed : CopyableClass { get {} set {} }  // expected-error {{'@NSCopying' is only valid on stored properties}}
 
-  @NSCopying var notClass : Int  // expected-error {{@NSCopying is only valid with types that conform to the NSCopying protocol}}
-  @NSCopying var x : NotCopyable    // expected-error {{@NSCopying is only valid with types that conform to the NSCopying protocol}}
+  @NSCopying var notClass : Int  // expected-error {{'@NSCopying' is only valid with types that conform to the NSCopying protocol}}
+  @NSCopying var x : NotCopyable    // expected-error {{'@NSCopying' is only valid with types that conform to the NSCopying protocol}}
 
   init() {}
   
diff --git a/test/decl/var/NSManaged_properties.swift b/test/decl/var/NSManaged_properties.swift
index c45609aceecca..e2dc01fd7347a 100644
--- a/test/decl/var/NSManaged_properties.swift
+++ b/test/decl/var/NSManaged_properties.swift
@@ -10,10 +10,10 @@ class X : NSObject {
 
 @NSManaged struct SomeStruct {} // expected-error {{'@NSManaged' attribute cannot be applied to this declaration}}
 
-@NSManaged var global: Int // expected-error {{@NSManaged only allowed on an instance property or method}}
+@NSManaged var global: Int // expected-error {{'@NSManaged' only allowed on an instance property or method}}
 
-// expected-error@+1 {{@NSManaged method cannot have a body; it must be provided at runtime}}
-@NSManaged     // expected-error {{@NSManaged only allowed on an instance property or method}}
+// expected-error@+1 {{'@NSManaged' method cannot have a body; it must be provided at runtime}}
+@NSManaged     // expected-error {{'@NSManaged' only allowed on an instance property or method}}
 func managedFunction() {}
 
 protocol SwiftProto { }
@@ -21,36 +21,36 @@ protocol SwiftProto { }
 class SwiftGizmo : A {
   @NSManaged var a: X
   @NSManaged var b: Int
-  @NSManaged let c: Int  // expected-error {{@NSManaged not allowed on a 'let' property}}
+  @NSManaged let c: Int  // expected-error {{'@NSManaged' not allowed on a 'let' property}}
   
-  // expected-error@+1{{@NSManaged property cannot have an initial value}}
+  // expected-error@+1{{'@NSManaged' property cannot have an initial value}}
   @NSManaged var gizmo: SwiftGizmo = SwiftGizmo()
   
-  // expected-error@+1{{@NSManaged not allowed on computed properties}}
+  // expected-error@+1{{'@NSManaged' not allowed on computed properties}}
   @NSManaged var computed_var: Int {
     return 5
   }
 
-  // expected-error@+1{{@NSManaged not allowed on observing properties}}
+  // expected-error@+1{{'@NSManaged' not allowed on observing properties}}
   @NSManaged var observing_var: Int {
     willSet { }
   }
 
-  // expected-error@+1{{property cannot be marked @NSManaged because its type cannot be represented in Objective-C}}
+  // expected-error@+1{{property cannot be marked '@NSManaged' because its type cannot be represented in Objective-C}}
   @NSManaged var nonobjc_var: SwiftProto?
 
-  // expected-error@+2 {{@NSManaged only allowed on an instance property or method}}
-  // expected-error@+1 {{@NSManaged property cannot have an initial value}}
+  // expected-error@+2 {{'@NSManaged' only allowed on an instance property or method}}
+  // expected-error@+1 {{'@NSManaged' property cannot have an initial value}}
   @NSManaged class var d: Int = 4
 
-  @NSManaged var e: Int { return 4 } // expected-error {{@NSManaged not allowed on computed properties}}
+  @NSManaged var e: Int { return 4 } // expected-error {{'@NSManaged' not allowed on computed properties}}
 
-  @NSCopying @NSManaged var optionalProperty : NSString?  // expected-error {{@NSManaged property cannot also be marked @NSCopying}}
+  @NSCopying @NSManaged var optionalProperty : NSString?  // expected-error {{'@NSManaged' property cannot also be marked '@NSCopying'}}
 
   @NSManaged func mutableArrayValueForA() // no-warning
-  @NSManaged func mutableArrayValueForB() {} // expected-error {{NSManaged method cannot have a body; it must be provided at runtime}}
-  @NSManaged class func mutableArrayValueForA() {} // expected-error {{@NSManaged only allowed on an instance property or method}}
-  // expected-error@-1 {{@NSManaged method cannot have a body; it must be provided at runtime}}
+  @NSManaged func mutableArrayValueForB() {} // expected-error {{'@NSManaged' method cannot have a body; it must be provided at runtime}}
+  @NSManaged class func mutableArrayValueForA() {} // expected-error {{'@NSManaged' only allowed on an instance property or method}}
+  // expected-error@-1 {{'@NSManaged' method cannot have a body; it must be provided at runtime}}
 
   // (https://github.com/apple/swift/issues/43662) Don't assert.
   @NSManaged var multiA, multiB, multiC : NSNumber?
diff --git a/test/decl/var/init_accessors.swift b/test/decl/var/init_accessors.swift
index b280fe089c624..0646d9be38ada 100644
--- a/test/decl/var/init_accessors.swift
+++ b/test/decl/var/init_accessors.swift
@@ -57,14 +57,14 @@ func test_use_of_initializes_accesses_on_non_inits() {
       get { y }
 
       @storageRestrictions(initializes: y)
-      // expected-error@-1 {{@storageRestrictions attribute could only be used with init accessors}}
+      // expected-error@-1 {{'@storageRestrictions' could only be used with init accessors}}
       set(initialValue) {}
     }
 
     var _q: String {
       get { y }
       @storageRestrictions(accesses: x)
-      // expected-error@-1 {{@storageRestrictions attribute could only be used with init accessors}}
+      // expected-error@-1 {{'@storageRestrictions' could only be used with init accessors}}
       set(initialValue) {}
     }
 
@@ -604,7 +604,7 @@ func test_invalid_storage_restrictions() {
 
     var a: Int {
       @storageRestrictions()
-      // expected-error@-1 {{missing label in @storageRestrictions attribute}}
+      // expected-error@-1 {{missing label in '@storageRestrictions'}}
       init {}
 
       get { _a }
@@ -612,7 +612,7 @@ func test_invalid_storage_restrictions() {
 
     var b: Int {
       @storageRestrictions(initializes:)
-      // expected-error@-1 {{expected property name in @storageRestrictions list}}
+      // expected-error@-1 {{expected property name in '@storageRestrictions' list}}
       init {}
 
       get { _b }
@@ -620,7 +620,7 @@ func test_invalid_storage_restrictions() {
 
     var c: Int {
       @storageRestrictions(initializes: a, initializes: b)
-      // expected-error@-1 {{duplicate label 'initializes' in @storageRestrictions attribute}}
+      // expected-error@-1 {{duplicate label 'initializes' in '@storageRestrictions'}}
       // expected-error@-2 {{init accessor cannot refer to property 'a'; init accessors can refer only to stored properties}}
       init {}
 
@@ -629,7 +629,7 @@ func test_invalid_storage_restrictions() {
 
     var d: Int {
       @storageRestrictions(accesses: a, accesses: c)
-      // expected-error@-1 {{duplicate label 'accesses' in @storageRestrictions attribute}}
+      // expected-error@-1 {{duplicate label 'accesses' in '@storageRestrictions'}}
       // expected-error@-2 {{init accessor cannot refer to property 'a'; init accessors can refer only to stored properties}}
       init {}
 
@@ -638,7 +638,7 @@ func test_invalid_storage_restrictions() {
 
     var e: Int {
       @storageRestrictions(initialize: a, b, accesses: c, d)
-      // expected-error@-1 {{unexpected label 'initialize' in @storageRestrictions attribute}}
+      // expected-error@-1 {{unexpected label 'initialize' in '@storageRestrictions'}}
       init {}
 
       get { 0 }
@@ -653,7 +653,7 @@ func test_invalid_storage_restrictions() {
 
     var g: Int {
       @storageRestrictions(initializes: _a)
-      // expected-error@-1 {{@storageRestrictions attribute could only be used with init accessors}}
+      // expected-error@-1 {{'@storageRestrictions' could only be used with init accessors}}
       get { 0 }
     }
 
diff --git a/test/decl/var/properties.swift b/test/decl/var/properties.swift
index 8d91ba88e9997..ad1f6e8ba9843 100644
--- a/test/decl/var/properties.swift
+++ b/test/decl/var/properties.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 func markUsed<T>(_ t: T) {}
 
@@ -114,10 +114,11 @@ var x15: Int {
   // For the purpose of this test we need to use an attribute that cannot be
   // applied to the getter.
   weak
-  var foo: SomeClass? = SomeClass()  // expected-warning {{variable 'foo' was written to, but never read}}
-  // expected-warning@-1 {{instance will be immediately deallocated because variable 'foo' is 'weak'}}
-  // expected-note@-2 {{a strong reference is required to prevent the instance from being deallocated}}
-  // expected-note@-3 {{'foo' declared here}}
+  var foo: SomeClass? = SomeClass()
+  // expected-warning@-1 {{variable 'foo' was never used; consider replacing with '_' or removing it}}
+  // expected-warning@-2 {{instance will be immediately deallocated because variable 'foo' is 'weak'}}
+  // expected-note@-3 {{a strong reference is required to prevent the instance from being deallocated}}
+  // expected-note@-4 {{'foo' declared here}}
   return 0
 }
 
@@ -483,6 +484,13 @@ extension ProtocolWithExtension1 {
   static var fooExtStatic = 4 // expected-error{{static stored properties not supported in protocol extensions}}
 }
 
+// https://github.com/swiftlang/swift/issues/83969
+// Make sure we don't crash.
+public struct PublicTypeWithExt {}
+extension PublicTypeWithExt {
+  public var foo: Int? // expected-error {{extensions must not contain stored properties}}
+}
+
 protocol ProtocolWithExtension2 {
   var bar: String { get }
 }
diff --git a/test/decl/var/property_wrappers.swift b/test/decl/var/property_wrappers.swift
index c7cf4785198cd..48952ee744383 100644
--- a/test/decl/var/property_wrappers.swift
+++ b/test/decl/var/property_wrappers.swift
@@ -92,7 +92,7 @@ struct NonVisibleInitWrapper<Value> {
 struct InitialValueTypeMismatch<Value> {
   var wrappedValue: Value // expected-note{{'wrappedValue' declared here}}
 
-  init(wrappedValue initialValue: Value?) { // expected-error{{'init(wrappedValue:)' parameter type ('Value?') must be the same as its 'wrappedValue' property type ('Value') or an @autoclosure thereof}} {{documentation-file=property-wrapper-requirements}}
+  init(wrappedValue initialValue: Value?) { // expected-error{{'init(wrappedValue:)' parameter type ('Value?') must be the same as its 'wrappedValue' property type ('Value') or an '@autoclosure' thereof}} {{documentation-file=property-wrapper-requirements}}
     self.wrappedValue = initialValue!
   }
 }
@@ -101,10 +101,10 @@ struct InitialValueTypeMismatch<Value> {
 struct MultipleInitialValues<Value> {
   var wrappedValue: Value? = nil // expected-note 2{{'wrappedValue' declared here}}
 
-  init(wrappedValue initialValue: Int) { // expected-error{{'init(wrappedValue:)' parameter type ('Int') must be the same as its 'wrappedValue' property type ('Value?') or an @autoclosure thereof}}
+  init(wrappedValue initialValue: Int) { // expected-error{{'init(wrappedValue:)' parameter type ('Int') must be the same as its 'wrappedValue' property type ('Value?') or an '@autoclosure' thereof}}
   }
 
-  init(wrappedValue initialValue: Double) { // expected-error{{'init(wrappedValue:)' parameter type ('Double') must be the same as its 'wrappedValue' property type ('Value?') or an @autoclosure thereof}}
+  init(wrappedValue initialValue: Double) { // expected-error{{'init(wrappedValue:)' parameter type ('Double') must be the same as its 'wrappedValue' property type ('Value?') or an '@autoclosure' thereof}}
   }
 }
 
diff --git a/test/decl/var/property_wrappers_invalid.swift b/test/decl/var/property_wrappers_invalid.swift
index f6b351557598c..c228e83ed69a0 100644
--- a/test/decl/var/property_wrappers_invalid.swift
+++ b/test/decl/var/property_wrappers_invalid.swift
@@ -1,11 +1,14 @@
 // RUN: %target-swift-frontend -typecheck %s -verify -verify-ignore-unknown
 
 // FIXME: This should produce a diagnostic with a proper
-// source location. Right now, we just get three useless errors:
+// source location. Right now, we just get these errors:
 
-// <unknown>:0: error: type of expression is ambiguous without a type annotation
-// <unknown>:0: error: type of expression is ambiguous without a type annotation
-// <unknown>:0: error: type of expression is ambiguous without a type annotation
+// <unknown>:0: error: cannot infer key path type from context; consider explicitly specifying a root type
+// <unknown>:0: error: cannot infer key path type from context; consider explicitly specifying a root type
+// <unknown>:0: error: cannot infer key path type from context; consider explicitly specifying a root type
+// <unknown>:0: error: cannot infer key path type from context; consider explicitly specifying a root type
+// <unknown>:0: error: cannot infer key path type from context; consider explicitly specifying a root type
+// <unknown>:0: error: cannot infer key path type from context; consider explicitly specifying a root type
 
 // The actual problem is the type of the subscript declaration is wrong.
 
diff --git a/test/decl/var/result_builders.swift b/test/decl/var/result_builders.swift
index 863e55e03b0b0..9f3d09887d4f8 100644
--- a/test/decl/var/result_builders.swift
+++ b/test/decl/var/result_builders.swift
@@ -65,9 +65,9 @@ func makerParamAutoclosure(@Maker // expected-error {{result builder attribute '
                            fn: @autoclosure () -> ()) {}
 
 @resultBuilder
-struct GenericMaker<T> {} // expected-note {{generic type 'GenericMaker' declared here}} expected-error {{result builder must provide at least one static 'buildBlock' method}}
+struct GenericMaker<T> {} // expected-note {{generic struct 'GenericMaker' declared here}} expected-error {{result builder must provide at least one static 'buildBlock' method}}
 
-struct GenericContainer<T> {  // expected-note {{generic type 'GenericContainer' declared here}}
+struct GenericContainer<T> {  // expected-note {{generic struct 'GenericContainer' declared here}}
   @resultBuilder
   struct Maker {} // expected-error {{result builder must provide at least one static 'buildBlock' method}}
 }
diff --git a/test/decl/var/result_builders_availability.swift b/test/decl/var/result_builders_availability.swift
index ff7c02c62e18f..93bec41e1753b 100644
--- a/test/decl/var/result_builders_availability.swift
+++ b/test/decl/var/result_builders_availability.swift
@@ -68,7 +68,7 @@ enum Option {
 }
 
 @TupleBuilder
-func bestTuple() -> some Any { // expected-note{{add @available attribute to enclosing global function}}
+func bestTuple() -> some Any { // expected-note{{add '@available' attribute to enclosing global function}}
   "Hello"
   Option.best // expected-error{{'best' is only available in macOS 10.15.4 or newer}}
   // expected-note@-1{{add 'if #available' version check}}
diff --git a/test/decl/var/variables.swift b/test/decl/var/variables.swift
index e6733c272d139..3e436c8597a4e 100644
--- a/test/decl/var/variables.swift
+++ b/test/decl/var/variables.swift
@@ -15,7 +15,7 @@ var bfx : Int, bfy : Int
 _ = 10
 
 var self1 = self1
-// expected-note@-1 2{{through reference here}}
+// expected-note@-1 {{through reference here}}
 // expected-error@-2 {{circular reference}}
 
 var self2 : Int = self2
@@ -23,15 +23,15 @@ var (self3) : Int = self3
 var (self4) : Int = self4
 
 var self5 = self5 + self5
-// expected-note@-1 2{{through reference here}}
+// expected-note@-1 {{through reference here}}
 // expected-error@-2 {{circular reference}}
 
 var self6 = !self6
-// expected-note@-1 2{{through reference here}}
+// expected-note@-1 {{through reference here}}
 // expected-error@-2 {{circular reference}}
 
 var (self7a, self7b) = (self7b, self7a)
-// expected-note@-1 2{{through reference here}}
+// expected-note@-1 {{through reference here}}
 // expected-error@-2 {{circular reference}}
 
 var self8 = 0
@@ -87,16 +87,17 @@ var shouldWarnWithoutSugar = (arrayOfEmptyTuples as Array<()>) // expected-warni
 
 class SomeClass {}
 
-// <rdar://problem/16877304> weak let's should be rejected
-weak let V = SomeClass()  // expected-error {{'weak' must be a mutable variable, because it may change at runtime}}
+
+weak let V = SomeClass() // ok since SE-0481
+// expected-warning@-1 {{instance will be immediately deallocated because variable 'V' is 'weak'}}
+// expected-note@-2 {{'V' declared here}}
+// expected-note@-3 {{a strong reference is required to prevent the instance from being deallocated}}
 
 let a = b ; let b = a
-// expected-error@-1 {{circular reference}}
-// expected-note@-2 {{through reference here}}
-// expected-note@-3 {{through reference here}}
-// expected-note@-4 {{through reference here}}
-// expected-note@-5 {{through reference here}}
-// expected-note@-6 {{through reference here}}
+// expected-error@-1:1 {{circular reference}}
+// expected-note@-2:5 {{through reference here}}
+// expected-note@-3:13 {{through reference here}}
+// expected-note@-4:17 {{through reference here}}
 
 // <rdar://problem/17501765> Swift should warn about immutable default initialized values
 let uselessValue : String?
@@ -123,7 +124,12 @@ func test21057425() -> (Int, Int) {
 // rdar://problem/21081340
 func test21081340() {
   func foo() { }
+
+  // FIXME: The double diagnostic here is a little unfortunate but is a result of
+  // the fact that we essentially type-check the pattern twice, once on its own,
+  // and again as part of the initialization.
   let (x: a, y: b): () = foo() // expected-error{{tuple pattern has the wrong length for tuple type '()'}}
+  // expected-error@-1 {{pattern of type '(x: _, y: _)' cannot match '()'}}
 }
 
 // <rdar://problem/22322266> Swift let late initialization in top level control flow statements
diff --git a/test/diagnostics/Localization/en_localization.swift b/test/diagnostics/Localization/en_localization.swift
index 98bb0a39090bc..331d3490c74a6 100644
--- a/test/diagnostics/Localization/en_localization.swift
+++ b/test/diagnostics/Localization/en_localization.swift
@@ -3,7 +3,7 @@
 _ = "HI!
 // expected-error@-1{{unterminated string literal}}
 var self1 = self1
-// expected-note@-1 2{{through reference here}}
+// expected-note@-1 {{through reference here}}
 // expected-error@-2 {{circular reference}}
 
 struct Broken {
diff --git a/test/diagnostics/Localization/fr_localization.swift b/test/diagnostics/Localization/fr_localization.swift
index 206fd65d57900..724c54c5ca467 100644
--- a/test/diagnostics/Localization/fr_localization.swift
+++ b/test/diagnostics/Localization/fr_localization.swift
@@ -8,7 +8,7 @@ _ = "HI!
 
 // FIXME: This used to produce a localized diagnostic.
 
-var self1 = self1 // expected-note 2{{through reference here}}
+var self1 = self1 // expected-note {{through reference here}}
 // expected-error@-1 {{circular reference}}
 
 struct Broken {
diff --git a/test/diagnostics/Localization/no_localization_files_and_wrong_path.swift b/test/diagnostics/Localization/no_localization_files_and_wrong_path.swift
index 5394acfc4c050..19c9f874f0e47 100644
--- a/test/diagnostics/Localization/no_localization_files_and_wrong_path.swift
+++ b/test/diagnostics/Localization/no_localization_files_and_wrong_path.swift
@@ -6,7 +6,7 @@
 _ = "HI!
 // expected-error@-1{{unterminated string literal}}
 var self1 = self1
-// expected-note@-1 2{{through reference here}}
+// expected-note@-1 {{through reference here}}
 // expected-error@-2 {{circular reference}}
 
 struct Broken {
diff --git a/test/diagnostics/diagnostic-group-serialization.swift b/test/diagnostics/diagnostic-group-serialization.swift
index ac1f45000de1e..84e53948d02e8 100644
--- a/test/diagnostics/diagnostic-group-serialization.swift
+++ b/test/diagnostics/diagnostic-group-serialization.swift
@@ -10,7 +10,7 @@ func f() { }
 
 func g() {
   f()
-// CHECK: [[@LINE-1]]:3: warning: 'f()' is deprecated: please do not use [-W{{.*}}deprecated-declaration.md] [DeprecatedDeclaration]
+// CHECK: [[@LINE-1]]:3: warning: 'f()' is deprecated: please do not use [-W{{.*}}deprecated-declaration] [DeprecatedDeclaration]
 }
 
 
@@ -19,7 +19,7 @@ func beCareful() { }
 
 func test() {
   beCareful()
-// CHECK: [[@LINE-1]]:3: warning: expression uses unsafe constructs but is not marked with 'unsafe' [-W{{.*}}strict-memory-safety.md] [StrictMemorySafety]
+// CHECK: [[@LINE-1]]:3: warning: expression uses unsafe constructs but is not marked with 'unsafe' [-W{{.*}}strict-memory-safety] [StrictMemorySafety]
 }
 
-// CHECK: [StrictMemorySafety]: <{{.*}}strict-memory-safety.md>
+// CHECK: [StrictMemorySafety]: <{{.*}}strict-memory-safety>
diff --git a/test/diagnostics/educational_notes_serialization.swift b/test/diagnostics/educational_notes_serialization.swift
index dbfe239ada4ec..d24914dc6ca1a 100644
--- a/test/diagnostics/educational_notes_serialization.swift
+++ b/test/diagnostics/educational_notes_serialization.swift
@@ -7,13 +7,13 @@
 
 typealias Fn = () -> ()
 extension Fn {}
-// CHECK: [[@LINE-1]]:1: error: non-nominal type 'Fn' (aka '() -> ()') cannot be extended [{{.*}}nominal-types.md] [NominalTypes]
+// CHECK: [[@LINE-1]]:1: error: non-nominal type 'Fn' (aka '() -> ()') cannot be extended [{{.*}}nominal-types] [NominalTypes]
 
 
 // Shares the flag record with `Fn`
 typealias Dup = () -> ()
 extension Dup {}
-// CHECK: [[@LINE-1]]:1: error: non-nominal type 'Dup' (aka '() -> ()') cannot be extended [{{.*}}nominal-types.md] [NominalTypes]
+// CHECK: [[@LINE-1]]:1: error: non-nominal type 'Dup' (aka '() -> ()') cannot be extended [{{.*}}nominal-types] [NominalTypes]
 
 do {
   func noNote(_: Int) {}
diff --git a/test/diagnostics/print-diagnostic-groups.swift b/test/diagnostics/print-diagnostic-groups.swift
index 189296c1d0c6f..9e1fd54391f14 100644
--- a/test/diagnostics/print-diagnostic-groups.swift
+++ b/test/diagnostics/print-diagnostic-groups.swift
@@ -1,5 +1,5 @@
 // RUN: %target-swift-frontend -typecheck %s 2>&1 | %FileCheck %s --check-prefix=CHECK-FILE -check-prefix CHECK
-// RUN: %target-swift-frontend -typecheck %s -diagnostic-documentation-path https://www.swift.org/documentation/compiler/diagnostics/ 2>&1 | %FileCheck %s --check-prefix=CHECK-HTTPS -check-prefix CHECK
+// RUN: %target-swift-frontend -typecheck %s -diagnostic-documentation-path https://docs.swift.org/compiler/documentation/diagnostics/ 2>&1 | %FileCheck %s --check-prefix=CHECK-HTTPS -check-prefix CHECK
 // REQUIRES: swift_swift_parser
 
 // CHECK: warning: file 'print-diagnostic-groups.swift' is part of module 'main'; ignoring import{{$}}
@@ -16,4 +16,4 @@ bar()
 
 // CHECK-FILE: [#DeprecatedDeclarations]: <file://{{.*}}deprecated-declaration.md>
 
-// CHECK-HTTPS: [#DeprecatedDeclaration]: <https://www.swift.org/documentation/compiler/diagnostics/deprecated-declaration.md>
+// CHECK-HTTPS: [#DeprecatedDeclaration]: <https://docs.swift.org/compiler/documentation/diagnostics/deprecated-declaration>
diff --git a/test/diagnostics/verifier.swift b/test/diagnostics/verifier.swift
deleted file mode 100644
index c281838af54e4..0000000000000
--- a/test/diagnostics/verifier.swift
+++ /dev/null
@@ -1,54 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: not %target-swift-frontend -typecheck -verify -serialize-diagnostics-path %t/serialized.dia -emit-fixits-path %t/fixits %s 2>&1 | %FileCheck %s
-// RUN: not %target-swift-frontend -typecheck -verify -warnings-as-errors %s 2>&1 | %FileCheck %s -check-prefix CHECK-WARNINGS-AS-ERRORS
-// RUN: %FileCheck %s -check-prefix CHECK-SERIALIZED <%t/serialized.dia
-// RUN: %FileCheck %s -check-prefix CHECK-FIXITS <%t/fixits
-
-// Wrong message
-let x: Int = "hello, world!" // expected-error {{foo bar baz}}
-// CHECK-NOT: error: cannot convert value of type 'String' to specified type 'Int'
-// CHECK: error: incorrect message found
-
-// Wrong column
-let y: Int = "hello, world!" // expected-error@:49 {{cannot convert value of type}}
-// CHECK: message found at column 14 but was expected to appear at column 49
-
-// Wrong fix-it
-let z: Int = "hello, world!" as Any
-// expected-error@-1 {{cannot convert value of type}} {{3-3=foobarbaz}}
-// CHECK: expected fix-it not seen; actual fix-it seen: {{[{][{]}}36-36= as! Int{{[}][}]}}
-
-// Expected no fix-it
-let a: Bool = "hello, world!" as Any
-// expected-error@-1 {{cannot convert value of type}} {{none}}
-// CHECK: expected no fix-its; actual fix-it seen: {{[{][{]}}37-37= as! Bool{{[}][}]}}
-
-// Unexpected error
-_ = foo()
-// CHECK: unexpected error produced: cannot find 'foo' in scope
-
-func b() {
-  let c = 2
-}
-// CHECK: unexpected warning produced: initialization of immutable value 'c' was never used
-// CHECK-WARNINGS-AS-ERRORS: unexpected error produced: initialization of immutable value 'c' was never used
-
-typealias Crap = () -> ()
-extension Crap {} // expected-error {{non-nominal type 'Crap' (aka '() -> ()') cannot be extended}} {{documentation-file=foo-bar-baz}}
-// CHECK: error: expected documentation file not seen; actual documentation file: {{[{][{]}}documentation-file=nominal-types{{[}][}]}}
-
-extension Crap {} // expected-error {{non-nominal type 'Crap' (aka '() -> ()') cannot be extended}} {{documentation-file=nominal-types}} {{documentation-file=nominal-types}}
-// CHECK: error: each verified diagnostic may only have one {{[{][{]}}documentation-file=<#notes#>{{[}][}]}} declaration
-
-extension Crap {} // expected-error {{non-nominal type 'Crap' (aka '() -> ()') cannot be extended}} {{documentation-file=nominal-types,foo-bar-baz}}
-// CHECK: error: expected documentation file not seen; actual documentation file: {{[{][{]}}documentation-file=nominal-types{{[}][}]}}
-
-// Verify the serialized diags have the right magic at the top.
-// CHECK-SERIALIZED: DIA
-
-// Ensure the verifier doesn't interfere with -emit-fixits-path.
-// CHECK-FIXITS: {
-// CHECK-FIXITS: "file":
-// CHECK-FIXITS: "offset":
-// CHECK-FIXITS: "text": " as! Int"
-// CHECK-FIXITS: }
diff --git a/test/embedded/Inputs/executor.c b/test/embedded/Inputs/executor.c
index 7032b3af833d3..cf5f9455fc565 100644
--- a/test/embedded/Inputs/executor.c
+++ b/test/embedded/Inputs/executor.c
@@ -308,7 +308,7 @@ void swift_task_checkIsolatedImpl(SwiftExecutorRef executor) {
 
 /// Check if the specified executor is the current executor.
 SWIFT_CC(swift)
-bool swift_task_isIsolatingCurrentContextImpl(SwiftExecutorRef executor) {
+int8_t swift_task_isIsolatingCurrentContextImpl(SwiftExecutorRef executor) {
   return swift_executor_invokeSwiftIsIsolatingCurrentContext(executor);
 }
 
diff --git a/test/embedded/Inputs/linux-rng-support.c b/test/embedded/Inputs/linux-rng-support.c
index 697b630786dc3..c4688c3e16115 100644
--- a/test/embedded/Inputs/linux-rng-support.c
+++ b/test/embedded/Inputs/linux-rng-support.c
@@ -5,14 +5,8 @@
 
 #ifdef __linux__ 
 
-#ifdef __cplusplus
-extern "C"
-#endif
 ssize_t getrandom(void *buf, size_t len, unsigned int flags);
 
-#ifdef __cplusplus
-extern "C"
-#endif
 void arc4random_buf(void *buf, size_t nbytes);
 
 void arc4random_buf(void *buf, size_t nbytes) {
diff --git a/test/embedded/accessors.swift b/test/embedded/accessors.swift
new file mode 100644
index 0000000000000..6e10d46528fed
--- /dev/null
+++ b/test/embedded/accessors.swift
@@ -0,0 +1,37 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -Onone -parse-as-library -enable-experimental-feature Embedded -c -o %t/main.o
+// RUN: %target-clang %target-clang-resource-dir-opt %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: optimized_stdlib
+// REQUIRES: swift_feature_Embedded
+
+public class C {
+  public var x: Int {
+    _read {
+      yield(y)
+    }
+    _modify {
+      yield(&y)
+    }
+  }
+
+  var y: Int = 27
+}
+
+@main
+struct Main {
+  static func main() {
+    print("1") // CHECK: 1
+    let c = C() // CHECK: 27
+    print(c.y)
+    c.y = 28
+    print(c.y) // CHECK: 28
+    print("")
+
+    print("2") // CHECK: 2
+    print("")
+  }
+}
diff --git a/test/embedded/anyobject.swift b/test/embedded/anyobject.swift
new file mode 100644
index 0000000000000..fb6849543424b
--- /dev/null
+++ b/test/embedded/anyobject.swift
@@ -0,0 +1,36 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo -swift-version 5) | %FileCheck %s
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo -O -swift-version 5) | %FileCheck %s
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo -Osize -swift-version 5) | %FileCheck %s
+
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo -swift-version 6) | %FileCheck %s
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo -O -swift-version 6) | %FileCheck %s
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo -Osize -swift-version 6) | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: optimized_stdlib
+// REQUIRES: swift_feature_Embedded
+
+protocol P: AnyObject {}
+
+class C: P {}
+
+@main
+struct Main {
+    static func main() {
+        let p1: any P = C()
+        let p2: any P = C()
+        let p3 = p1
+
+        // CHECK: false
+        print(p1 === p2)
+        print(p2 === p1)
+        // CHECK: true
+        print(p1 === p3)
+        print(p3 === p1)
+        // CHECK: false
+        print(p2 === p3)
+        print(p3 === p2)
+   }
+}
+
diff --git a/test/embedded/array-builtins-exec.swift b/test/embedded/array-builtins-exec.swift
index c13037769ff71..c59c5d2481598 100644
--- a/test/embedded/array-builtins-exec.swift
+++ b/test/embedded/array-builtins-exec.swift
@@ -1,7 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend %s -parse-as-library -enable-experimental-feature Embedded -enable-builtin-module -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
-// RUN: %target-run %t/a.out | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library -enable-experimental-feature Embedded -wmo -enable-builtin-module) | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: executable_test
@@ -41,7 +39,7 @@ func exerciseArrayValueWitnesses<T>(_ value: T) {
 
   (buf + 0).initialize(to: value)
   (buf + 1).initialize(to: value)
-  
+
   Builtin.copyArray(T.self, (buf + 2)._rawValue, buf._rawValue, 2._builtinWordValue)
   Builtin.takeArrayBackToFront(T.self, (buf + 1)._rawValue, buf._rawValue, 4._builtinWordValue)
   Builtin.takeArrayFrontToBack(T.self, buf._rawValue, (buf + 1)._rawValue, 4._builtinWordValue)
diff --git a/test/embedded/attr-unavailable-in-embedded.swift b/test/embedded/attr-unavailable-in-embedded.swift
index b35f0a1c171b3..9e5b93fe8227d 100644
--- a/test/embedded/attr-unavailable-in-embedded.swift
+++ b/test/embedded/attr-unavailable-in-embedded.swift
@@ -2,7 +2,7 @@
 // RUN: %{python} %utils/split_file.py -o %t %s
 
 // RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-stdlib -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-swift-frontend -typecheck -verify -I %t %t/Main.swift -parse-stdlib -enable-experimental-feature Embedded
+// RUN: %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -I %t %t/Main.swift -parse-stdlib -enable-experimental-feature Embedded
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_Embedded
diff --git a/test/embedded/availability.swift b/test/embedded/availability.swift
index 15f1be053bbbb..162699c1f90c8 100644
--- a/test/embedded/availability.swift
+++ b/test/embedded/availability.swift
@@ -9,7 +9,7 @@ public struct UnavailableInEmbedded {}
 
 @available(*, unavailable, message: "always unavailable")
 public struct UniverallyUnavailable {}
-// expected-note@-1 {{'UniverallyUnavailable' has been explicitly marked unavailable here}}
+// expected-note@-1 3 {{'UniverallyUnavailable' has been explicitly marked unavailable here}}
 
 @_unavailableInEmbedded
 public func unavailable_in_embedded() { }
@@ -41,7 +41,7 @@ public struct Available {}
 extension Available {
   public func unavailable_in_embedded_method( // expected-note {{'unavailable_in_embedded_method' has been explicitly marked unavailable here}}
     _ uie: UnavailableInEmbedded,
-    _ uu: UniverallyUnavailable,
+    _ uu: UniverallyUnavailable, // expected-error {{'UniverallyUnavailable' is unavailable: always unavailable}}
     _ a: Available,
   ) {
     unavailable_in_embedded()
@@ -65,7 +65,7 @@ public func available(
 @_unavailableInEmbedded
 public func also_unavailable_in_embedded(
   _ uie: UnavailableInEmbedded, // OK
-  _ uu: UniverallyUnavailable, // OK
+  _ uu: UniverallyUnavailable, // expected-error {{'UniverallyUnavailable' is unavailable: always unavailable}}
   _ a: Available,
 ) {
   unavailable_in_embedded() // OK
@@ -87,3 +87,41 @@ public func also_universally_unavailable(
   has_unavailable_in_embedded_overload(.init()) // expected-error {{ambiguous use of 'init()'}}
   has_universally_unavailable_overload(.init()) // not ambiguous, selects available overload
 }
+
+class Base {
+  func alwaysAvailable() { }
+
+  @_unavailableInEmbedded
+  func overrideAsUnavailable() { }
+
+  @_unavailableInEmbedded
+  func overrideLessUnavailable() { } // expected-note {{'overrideLessUnavailable()' has been explicitly marked unavailable here}}
+
+  func overrideMoreUnavailable() { } // expected-note {{overridden declaration is here}}
+}
+
+class DerivedAvailable: Base {
+  override func alwaysAvailable() { }
+
+  @_unavailableInEmbedded
+  override func overrideAsUnavailable() { }
+
+  override func overrideLessUnavailable() { } // expected-error {{cannot override 'overrideLessUnavailable' which has been marked unavailable}}
+  // expected-note@-1 {{remove 'override' modifier to declare a new 'overrideLessUnavailable'}}
+
+  @_unavailableInEmbedded
+  override func overrideMoreUnavailable() { } // expected-error {{cannot override 'overrideMoreUnavailable' with a declaration that is marked unavailable}}{{112:3-26=}}
+}
+
+@_unavailableInEmbedded
+class DerivedUnavailable: Base {
+  override func alwaysAvailable() { }
+
+  @_unavailableInEmbedded
+  override func overrideAsUnavailable() { }
+
+  override func overrideLessUnavailable() { }
+
+  @_unavailableInEmbedded
+  override func overrideMoreUnavailable() { }
+}
diff --git a/test/embedded/avr/testStdlibFunctioning.swift b/test/embedded/avr/testStdlibFunctioning.swift
index 3588343709430..3c614444acdb7 100644
--- a/test/embedded/avr/testStdlibFunctioning.swift
+++ b/test/embedded/avr/testStdlibFunctioning.swift
@@ -3,6 +3,7 @@
 // REQUIRES: embedded_stdlib_cross_compiling
 // REQUIRES: CODEGENERATOR=AVR
 // REQUIRES: swift_feature_Embedded
+// UNSUPPORTED: CPU=wasm32
 
 import Swift
 
diff --git a/test/embedded/basic-modules-generics-no-stdlib.swift b/test/embedded/basic-modules-generics-no-stdlib.swift
index bb4f11507b8c6..ebe9220378233 100644
--- a/test/embedded/basic-modules-generics-no-stdlib.swift
+++ b/test/embedded/basic-modules-generics-no-stdlib.swift
@@ -52,7 +52,7 @@ public func main() {
   protocolBoundFunc(GenericType<Bool>(Bool()))
 }
 
-// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}(i32 %0, ptr %1)
 // CHECK: define {{.*}}void @"$e4Main4BoolVACycfC"()
 // CHECK: define {{.*}}void @"$e4Main4mainyyF"()
 // CHECK: define {{.*}}void @"$e8MyModule14nonGenericFuncyyF"()
diff --git a/test/embedded/basic-modules-no-stdlib.swift b/test/embedded/basic-modules-no-stdlib.swift
index 891e8ef6234c9..ed63816ef7c8a 100644
--- a/test/embedded/basic-modules-no-stdlib.swift
+++ b/test/embedded/basic-modules-no-stdlib.swift
@@ -38,7 +38,7 @@ public func main() {
   moduleMain()
 }
 
-// CHECK: define {{.*}}@main{{.*}} {
+// CHECK: define {{.*}}@{{_*}}main{{.*}} {
 // CHECK: define {{.*}}void @"$e4Main4mainyyF"{{.*}} {
 // CHECK: define {{.*}}void @"$e8MyModule10moduleMainyyF"{{.*}} {
 // CHECK: define {{.*}}void @"$e8MyModule8ConcreteVACycfC"{{.*}} {
diff --git a/test/embedded/basic-modules-validation-no-stdlib.swift b/test/embedded/basic-modules-validation-no-stdlib.swift
index e37edf570ba70..750098583880f 100644
--- a/test/embedded/basic-modules-validation-no-stdlib.swift
+++ b/test/embedded/basic-modules-validation-no-stdlib.swift
@@ -6,7 +6,7 @@
 // RUN: %target-swift-frontend -emit-ir -I %t %t/Main.swift -parse-stdlib -enable-experimental-feature Embedded -wmo
 
 // MyModule is not embedded - error
-// RUN: %target-swift-frontend -emit-module -enable-ossa-modules -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-stdlib -wmo
+// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-stdlib -wmo
 // RUN: not %target-swift-frontend -emit-ir -I %t %t/Main.swift -parse-stdlib -enable-experimental-feature Embedded -wmo 2>&1 | %FileCheck %s --check-prefix CHECK-A
 
 // main module is not embedded - error
diff --git a/test/embedded/builtin-float.swift b/test/embedded/builtin-float.swift
new file mode 100644
index 0000000000000..0e1cbc5526f00
--- /dev/null
+++ b/test/embedded/builtin-float.swift
@@ -0,0 +1,30 @@
+// RUN: %empty-directory(%t)
+// RUN: mkdir -p %t/include
+// RUN: %{python} %utils/split_file.py -o %t %s
+
+// RUN: %target-swift-frontend -target armv7em-none-none-eabi -emit-ir %t/Main.swift -enable-experimental-feature Embedded -module-cache-path %t/ModuleCache -Xcc -I%t/include
+
+// UNSUPPORTED: CPU=wasm32
+// REQUIRES: swift_in_compiler
+// REQUIRES: optimized_stdlib
+// REQUIRES: CODEGENERATOR=ARM
+// REQUIRES: embedded_stdlib_cross_compiling
+// REQUIRES: swift_feature_Embedded
+
+// BEGIN Main.swift
+
+print("hello")
+
+// BEGIN include/stdint.h
+
+#include <float.h>
+typedef __INTPTR_TYPE__ intptr_t;
+typedef __UINTPTR_TYPE__ uintptr_t;
+typedef __INT64_TYPE__ int64_t;
+typedef __UINT64_TYPE__ uint64_t;
+typedef __INT32_TYPE__ int32_t;
+typedef __UINT32_TYPE__ uint32_t;
+typedef __INT16_TYPE__ int16_t;
+typedef __UINT16_TYPE__ uint16_t;
+typedef __INT8_TYPE__ int8_t;
+typedef __UINT8_TYPE__ uint8_t;
diff --git a/test/embedded/classes-arrays.swift b/test/embedded/classes-arrays.swift
index 86fc128524821..e6883f2a8e685 100644
--- a/test/embedded/classes-arrays.swift
+++ b/test/embedded/classes-arrays.swift
@@ -1,7 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend %s -parse-as-library -enable-experimental-feature Embedded -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
-// RUN: %target-run %t/a.out | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library -enable-experimental-feature Embedded -wmo) | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: executable_test
@@ -56,7 +54,7 @@ struct Main {
       // CHECK: MySubSubClass.foo
     }
     print("")
-    
+
     print("5") // CHECK: 5
     objects = []
     // CHECK: MyClass.deinit
diff --git a/test/embedded/classes-generic-no-stdlib.swift b/test/embedded/classes-generic-no-stdlib.swift
index 04a245c065840..580865fce0a9f 100644
--- a/test/embedded/classes-generic-no-stdlib.swift
+++ b/test/embedded/classes-generic-no-stdlib.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-emit-sil %s -parse-stdlib -enable-experimental-feature Embedded -target arm64e-apple-none -wmo | %FileCheck %s --check-prefix CHECK-SIL
 // RUN: %target-swift-emit-ir %s -parse-stdlib -enable-experimental-feature Embedded -target arm64e-apple-none -wmo | %FileCheck %s --check-prefix CHECK-IR
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_Embedded
 
@@ -34,14 +35,6 @@ public func bar(t: T2) -> MyClass<T2> {
 // CHECK-SIL-DAG: sil {{.*}}@$e4main7MyClassC1tACyxGx_tcfCAA2T2V_Tt0g5 {{.*}}{
 // CHECK-SIL-DAG: sil {{.*}}@$e4main7MyClassCfDAA2T2V_Tg5 {{.*}}{
 
-// CHECK-SIL: sil_vtable MyClass {
-// CHECK-SIL:   #MyClass.t!getter: <T> (MyClass<T>) -> () -> T : @$e4main7MyClassC1txvgAA2T1V_Tg5 // specialized MyClass.t.getter
-// CHECK-SIL:   #MyClass.t!setter: <T> (MyClass<T>) -> (T) -> () : @$e4main7MyClassC1txvsAA2T1V_Tg5 // specialized MyClass.t.setter
-// CHECK-SIL:   #MyClass.t!modify: <T> (MyClass<T>) -> () -> () : @$e4main7MyClassC1txvMAA2T1V_Tg5  // specialized MyClass.t.modify
-// CHECK-SIL:   #MyClass.init!allocator: <T> (MyClass<T>.Type) -> (T) -> MyClass<T> : @$e4main7MyClassC1tACyxGx_tcfCAA2T1V_Tg5  // specialized MyClass.__allocating_init(t:)
-// CHECK-SIL:   #MyClass.deinit!deallocator: @$e4main7MyClassCfDAA2T1V_Tg5  // specialized MyClass.__deallocating_deinit
-// CHECK-SIL: }
-
 // CHECK-SIL: sil_vtable $MyClass<T2> {
 // CHECK-SIL:   #MyClass.t!getter: <T> (MyClass<T>) -> () -> T : @$e4main7MyClassC1txvgAA2T2V_Tg5 // specialized MyClass.t.getter
 // CHECK-SIL:   #MyClass.t!setter: <T> (MyClass<T>) -> (T) -> () : @$e4main7MyClassC1txvsAA2T2V_Tg5 // specialized MyClass.t.setter
@@ -50,9 +43,17 @@ public func bar(t: T2) -> MyClass<T2> {
 // CHECK-SIL:   #MyClass.deinit!deallocator: @$e4main7MyClassCfDAA2T2V_Tg5  // specialized MyClass.__deallocating_deinit
 // CHECK-SIL: }
 
+// CHECK-SIL: sil_vtable $MyClass<T1> {
+// CHECK-SIL:   #MyClass.t!getter: <T> (MyClass<T>) -> () -> T : @$e4main7MyClassC1txvgAA2T1V_Tg5 // specialized MyClass.t.getter
+// CHECK-SIL:   #MyClass.t!setter: <T> (MyClass<T>) -> (T) -> () : @$e4main7MyClassC1txvsAA2T1V_Tg5 // specialized MyClass.t.setter
+// CHECK-SIL:   #MyClass.t!modify: <T> (MyClass<T>) -> () -> () : @$e4main7MyClassC1txvMAA2T1V_Tg5  // specialized MyClass.t.modify
+// CHECK-SIL:   #MyClass.init!allocator: <T> (MyClass<T>.Type) -> (T) -> MyClass<T> : @$e4main7MyClassC1tACyxGx_tcfCAA2T1V_Tg5  // specialized MyClass.__allocating_init(t:)
+// CHECK-SIL:   #MyClass.deinit!deallocator: @$e4main7MyClassCfDAA2T1V_Tg5  // specialized MyClass.__deallocating_deinit
+// CHECK-SIL: }
+
 
-// CHECK-IR: @"$e4main7MyClassCyAA2T2VGN" = {{.*}}<{ ptr, ptr, ptr, ptr, ptr, ptr, ptr }> <{ ptr null, ptr @"$e4main7MyClassCfDAA2T2V_Tg5", ptr null, ptr @"$e4main7MyClassC1txvgAA2T2V_Tg5", ptr @"$e4main7MyClassC1txvsAA2T2V_Tg5", ptr @"$e4main7MyClassC1txvMAA2T2V_Tg5", ptr @"$e4main7MyClassC1tACyxGx_tcfCAA2T2V_Tg5" }>
-// CHECK-IR: @"$e4main7MyClassCyAA2T1VGN" = {{.*}}<{ ptr, ptr, ptr, ptr, ptr, ptr, ptr }> <{ ptr null, ptr @"$e4main7MyClassCfDAA2T1V_Tg5", ptr null, ptr @"$e4main7MyClassC1txvgAA2T1V_Tg5", ptr @"$e4main7MyClassC1txvsAA2T1V_Tg5", ptr @"$e4main7MyClassC1txvMAA2T1V_Tg5", ptr @"$e4main7MyClassC1tACyxGx_tcfCAA2T1V_Tg5" }>
+// CHECK-IR-DAG: @"$e4main7MyClassCyAA2T2VGN" = {{.*}}<{ ptr, ptr, ptr, ptr, ptr, ptr, ptr }> <{ ptr null, ptr @"$e4main7MyClassCfDAA2T2V_Tg5", ptr null, ptr @"$e4main7MyClassC1txvgAA2T2V_Tg5", ptr @"$e4main7MyClassC1txvsAA2T2V_Tg5", ptr @"$e4main7MyClassC1txvMAA2T2V_Tg5", ptr @"$e4main7MyClassC1tACyxGx_tcfCAA2T2V_Tg5" }>
+// CHECK-IR-DAG: @"$e4main7MyClassCyAA2T1VGN" = {{.*}}<{ ptr, ptr, ptr, ptr, ptr, ptr, ptr }> <{ ptr null, ptr @"$e4main7MyClassCfDAA2T1V_Tg5", ptr null, ptr @"$e4main7MyClassC1txvgAA2T1V_Tg5", ptr @"$e4main7MyClassC1txvsAA2T1V_Tg5", ptr @"$e4main7MyClassC1txvMAA2T1V_Tg5", ptr @"$e4main7MyClassC1tACyxGx_tcfCAA2T1V_Tg5" }>
 
 // CHECK-IR-DAG: define {{.*}}void @"$e4main7MyClassC1txvgAA2T1V_Tg5"(ptr swiftself %0)
 // CHECK-IR-DAG: define {{.*}}i1 @"$e4main7MyClassC1txvgAA2T2V_Tg5"(ptr swiftself %0)
diff --git a/test/embedded/classes-multi-module.swift b/test/embedded/classes-multi-module.swift
new file mode 100644
index 0000000000000..a444fac53b3d0
--- /dev/null
+++ b/test/embedded/classes-multi-module.swift
@@ -0,0 +1,58 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -c -I%t -parse-as-library %t/MyModule.swift -o %t/MyModule.o -emit-module -emit-module-path %t/MyModule.swiftmodule -emit-empty-object-file
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -c -I%t %t/Main.swift -o %t/Main.o
+// RUN: %target-clang %target-clang-resource-dir-opt %t/Main.o %t/MyModule.o -o %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_Embedded
+
+//--- MyModule.swift
+
+public class C<T> {
+  public func foo() {
+    let x = X<Int>(x: 27)
+    x.bar()
+  }
+}
+
+class D<T>: C<T> {
+  override public func foo() {
+    print("D")
+  }
+}
+
+class X<T: BinaryInteger> {
+  var x: T
+
+  init(x: T) { self.x = x }
+
+  func bar() {
+    print(x)
+  }
+}
+
+class Y<T: BinaryInteger>: X<T> {
+  override func bar() {
+  }
+}
+
+@inline(never)
+public func create<T>(_ t: T.Type) -> C<T> {
+  return C<T>()
+}
+
+//--- Main.swift
+
+import MyModule
+
+@inline(never)
+public func testit() {
+  let c = create(Int.self)
+  c.foo()
+}
+
+// CHECK: 27
+testit()
diff --git a/test/embedded/classes-non-final-method-no-stdlib.swift b/test/embedded/classes-non-final-method-no-stdlib.swift
index ecd8c8465af37..35dbf29cade6a 100644
--- a/test/embedded/classes-non-final-method-no-stdlib.swift
+++ b/test/embedded/classes-non-final-method-no-stdlib.swift
@@ -4,26 +4,34 @@
 // REQUIRES: swift_feature_Embedded
 
 public class MyClass {
-  func foo<T>(t: T) { } // expected-error {{classes cannot have non-final generic functions in embedded Swift}}
-  func bar() { }
+  public func foo<T>(t: T) { } // expected-warning {{generic instance method 'foo(t:)' in a class must be 'final' in Embedded Swift}}
+  // expected-error@-1{{classes cannot have a non-final, generic method 'foo(t:)' in embedded Swift}}
+  public func bar() { }
 }
 
 final class C2<Element> {
-  // TODO: this shouldn't be a problem because the class is final
-  init<T>(x: T) { } // expected-error {{classes cannot have non-final generic functions in embedded Swift}}
+  init<T>(x: T) { }
 }
 
 struct S {}
 
+public func testMyClass(_ c: MyClass) {
+  c.foo(t: S())
+  c.bar()
+}
+
 func testit2() -> C2<S> {
   return C2(x: S())
 }
 
 open class C3<X> {
-  public func foo<T>(t: T) {} // expected-error {{classes cannot have non-final generic functions in embedded Swift}}
+  public func foo<T>(t: T) {} // expected-warning {{generic instance method 'foo(t:)' in a class must be 'final' in Embedded Swift}}
+  // expected-error@-1{{classes cannot have a non-final, generic method 'foo(t:)' in embedded Swift}}
 }
 
 func testit3() -> C3<S> {
-  return C3<S>()
+  let c = C3<S>()
+  c.foo(t: S())
+  return c
 }
 
diff --git a/test/embedded/classes-optional.swift b/test/embedded/classes-optional.swift
index 0229977022b2c..c379f638864c6 100644
--- a/test/embedded/classes-optional.swift
+++ b/test/embedded/classes-optional.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -enable-experimental-feature Embedded -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-clang %target-clang-resource-dir-opt %t/main.o -o %t/a.out -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
diff --git a/test/embedded/classes-stack-promotion.swift b/test/embedded/classes-stack-promotion.swift
index c2f1855a713c0..6220c1cef17b0 100644
--- a/test/embedded/classes-stack-promotion.swift
+++ b/test/embedded/classes-stack-promotion.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -O -Xllvm -sil-disable-pass=function-signature-opts %s -parse-as-library -enable-experimental-feature Embedded -module-name main -emit-irgen | %FileCheck %s --check-prefix CHECK-IR
 // RUN: %target-swift-frontend -O -Xllvm -sil-disable-pass=function-signature-opts %s -parse-as-library -enable-experimental-feature Embedded -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-clang %target-clang-resource-dir-opt %t/main.o -o %t/a.out -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
@@ -77,7 +77,7 @@ struct Main {
 // CHECK-IR-NEXT:   ret void
 // CHECK-IR-NEXT: }
 
-// CHECK-IR:      define {{.*}}@main
+// CHECK-IR:      define {{.*}}@{{_*}}main
 // CHECK-IR-NEXT: entry:
 // CHECK-IR-NEXT:   alloca %T4main10MySubClassC
 // CHECK-IR-NEXT:   alloca %T4main12MyFinalClassC
diff --git a/test/embedded/classes.swift b/test/embedded/classes.swift
index 14ecb79863d3a..5ca3ef093e19a 100644
--- a/test/embedded/classes.swift
+++ b/test/embedded/classes.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -parse-as-library -enable-experimental-feature Embedded -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-clang %target-clang-resource-dir-opt %t/main.o -o %t/a.out -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
@@ -84,7 +84,7 @@ struct Main {
     // CHECK: MySubClass.foo
     // CHECK: MySubSubClass.foo
     print("")
-    
+
     print("5") // CHECK: 5
     o.0 = nil
     // CHECK: MyClass.deinit
diff --git a/test/embedded/closures-heap.swift b/test/embedded/closures-heap.swift
index b685b345823a2..f9c220fe95aef 100644
--- a/test/embedded/closures-heap.swift
+++ b/test/embedded/closures-heap.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -parse-as-library -enable-experimental-feature Embedded -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-clang %target-clang-resource-dir-opt %t/main.o -o %t/a.out -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
@@ -8,6 +8,10 @@
 // REQUIRES: optimized_stdlib
 // REQUIRES: swift_feature_Embedded
 
+
+
+func f() -> Bool? { return nil }
+
 public class MyClass {
   var handler: (()->())? = nil
   func foo() {
@@ -32,5 +36,12 @@ struct Main {
     o!.foo() // CHECK: capture local
     print(local == 43 ? "43" : "???") // CHECK: 43
     o = nil // CHECK: deinit
+
+    let closure = {
+         guard var b = f() else { print("success"); return }
+         let c = { b = true }
+         _ = (b, c)
+    }
+    closure()   // CHECK: success
   }
 }
diff --git a/test/embedded/concurrency-actors.swift b/test/embedded/concurrency-actors.swift
index 694b24270681a..bbe3bc94721a7 100644
--- a/test/embedded/concurrency-actors.swift
+++ b/test/embedded/concurrency-actors.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
@@ -64,7 +64,7 @@ actor Number {
         let n1 = await Number()
         await n1.task!.value
 
-        let n2 = await Number(iterations: 1000)
+        let n2 = await Number(iterations: 500)
         let val = await n2.val
         guard val == 1 else {
             fatalError("wrong val setting")
diff --git a/test/embedded/concurrency-async-let.swift b/test/embedded/concurrency-async-let.swift
index 0cf725927f9fd..942bcc7e2c2f4 100644
--- a/test/embedded/concurrency-async-let.swift
+++ b/test/embedded/concurrency-async-let.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
diff --git a/test/embedded/concurrency-builtins.swift b/test/embedded/concurrency-builtins.swift
index f5242f4631ffc..c133d2342b7b6 100644
--- a/test/embedded/concurrency-builtins.swift
+++ b/test/embedded/concurrency-builtins.swift
@@ -2,7 +2,7 @@
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import Builtin
diff --git a/test/embedded/concurrency-continuations.swift b/test/embedded/concurrency-continuations.swift
index 0ae57902564ac..6716968861ba6 100644
--- a/test/embedded/concurrency-continuations.swift
+++ b/test/embedded/concurrency-continuations.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
diff --git a/test/embedded/concurrency-currenttask.swift b/test/embedded/concurrency-currenttask.swift
index a29b271681d03..e4b14a6b7140c 100644
--- a/test/embedded/concurrency-currenttask.swift
+++ b/test/embedded/concurrency-currenttask.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
diff --git a/test/embedded/concurrency-deleted-method.swift b/test/embedded/concurrency-deleted-method.swift
index 0ac66eefd3920..39f27305671c1 100644
--- a/test/embedded/concurrency-deleted-method.swift
+++ b/test/embedded/concurrency-deleted-method.swift
@@ -1,13 +1,13 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library -module-name main %s -emit-ir | %FileCheck --check-prefix=CHECK-IR %s
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library -module-name main %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
@@ -31,7 +31,7 @@ actor MyActor {
 }
 
 // CHECK-IR:      @swift_deletedAsyncMethodErrorTu =
-// CHECK-IR:      @"$e4main7MyActorCN" = global <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }> <{ 
+// CHECK-IR:      @"$e4main7MyActorCN" = global <{ ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }> <{
 // CHECK-IR-SAME:   ptr null,
 // CHECK-IR-SAME:   ptr @"$e4main7MyActorCfD",
 // CHECK-IR-SAME:   ptr null,
@@ -41,10 +41,10 @@ actor MyActor {
 // CHECK-IR-SAME:   ptr @"$e4main7MyActorC3fooyyYaFTu",
 // CHECK-IR-SAME:   ptr @got.swift_deletedAsyncMethodErrorTu,
 // CHECK-IR-SAME:   ptr @"$e4main7MyActorCACycfC"
-// CHECK-IR-SAME: }>, align 8
+// CHECK-IR-SAME: }>, align {{[48]}}
 
 // CHECK-IR-NOT:  $e4main7MyActorC12thisIsUnusedyyYaF
 
-// CHECK-IR: define swifttailcc void @swift_deletedAsyncMethodError(ptr swiftasync %0)
+// CHECK-IR: define weak_odr {{swifttailcc|swiftcc}} void @swift_deletedAsyncMethodError(ptr swiftasync %0)
 
 // CHECK: value: 42
diff --git a/test/embedded/concurrency-discardingtaskgroup.swift b/test/embedded/concurrency-discardingtaskgroup.swift
index c3774e9bed2b1..b37ae64bbba36 100644
--- a/test/embedded/concurrency-discardingtaskgroup.swift
+++ b/test/embedded/concurrency-discardingtaskgroup.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-experimental-feature Embedded -target %target-cpu-apple-macos14 -parse-as-library %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lc++abi -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
diff --git a/test/embedded/concurrency-leaks.swift b/test/embedded/concurrency-leaks.swift
index ae4933fdf5c91..ed8c23020375b 100644
--- a/test/embedded/concurrency-leaks.swift
+++ b/test/embedded/concurrency-leaks.swift
@@ -1,13 +1,13 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o -g -O
 // RUN: %target-clang -x c -std=c11 -c %S/Inputs/debug-malloc.c -o %t/debug-malloc.o -g
-// RUN: %target-clang %t/a.o %t/debug-malloc.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip -g
+// RUN: %target-clang %t/a.o %t/debug-malloc.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt %target-swift-default-executor-opt -lswift_Concurrency %target-swift-default-executor-opt -dead_strip -g
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
diff --git a/test/embedded/concurrency-modules.swift b/test/embedded/concurrency-modules.swift
new file mode 100644
index 0000000000000..d1bcf7cc47f34
--- /dev/null
+++ b/test/embedded/concurrency-modules.swift
@@ -0,0 +1,63 @@
+// RUN: %empty-directory(%t)
+// RUN: %{python} %utils/split_file.py -o %t %s
+
+// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t %t/Main.swift -enable-experimental-feature Embedded -o %t/a.o -parse-as-library
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: optimized_stdlib
+// REQUIRES: OS=macosx || OS=wasip1
+// REQUIRES: swift_feature_Embedded
+
+// BEGIN MyModule.swift
+
+import _Concurrency
+
+nonisolated(unsafe) var glob: UnsafeMutableRawPointer? = nil
+nonisolated(unsafe) var job: UnownedJob? = nil
+
+public final class MyCustomExecutor: SerialExecutor, @unchecked Sendable {
+    private init() {}
+
+    nonisolated(unsafe)
+    public static var shared: MyCustomExecutor = MyCustomExecutor()
+
+    public static func installGlobalExecutor() {
+        let fn: @convention(thin) () -> () = {
+            MyCustomExecutor.shared.unsafeEnqueue(job!)
+        }
+        glob = unsafeBitCast(fn, to: UnsafeMutableRawPointer?.self)
+    }
+
+    private func enqueue(_ job: UnownedJob, withDelay nanoseconds: UInt64) {}
+
+    private func unsafeEnqueue(_ job: UnownedJob) {
+        job.runSynchronously(on: self.asUnownedSerialExecutor())
+    }
+
+    public func enqueue(_ job: consuming ExecutorJob) {
+        unsafeEnqueue(UnownedJob(job))
+    }
+
+    public func asUnownedSerialExecutor() -> UnownedSerialExecutor {
+        return UnownedSerialExecutor(ordinary: self)
+    }
+}
+
+// BEGIN Main.swift
+
+import MyModule
+import _Concurrency
+
+@main
+struct Entrypoint {
+    static func main() async {
+        MyCustomExecutor.installGlobalExecutor()
+        print("OK!")
+    }
+}
+
+// CHECK: OK!
diff --git a/test/embedded/concurrency-simple.swift b/test/embedded/concurrency-simple.swift
index aaa45c289d134..ffa2817f4fe8f 100644
--- a/test/embedded/concurrency-simple.swift
+++ b/test/embedded/concurrency-simple.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-clang %target-clang-resource-dir-opt %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple -lc++ -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
diff --git a/test/embedded/concurrency-stream.swift b/test/embedded/concurrency-stream.swift
index 0a7ed1df852a4..ac4716a56fab0 100644
--- a/test/embedded/concurrency-stream.swift
+++ b/test/embedded/concurrency-stream.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-experimental-feature Embedded -target %target-cpu-apple-macos14 -parse-as-library %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
diff --git a/test/embedded/concurrency-taskgroup.swift b/test/embedded/concurrency-taskgroup.swift
index c6f318c3ca554..19951e56cbe31 100644
--- a/test/embedded/concurrency-taskgroup.swift
+++ b/test/embedded/concurrency-taskgroup.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-experimental-feature Embedded -target %target-cpu-apple-macos14 -parse-as-library %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lc++abi -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
diff --git a/test/embedded/concurrency-typed-throws.swift b/test/embedded/concurrency-typed-throws.swift
index c7d5ab558bf36..3f47cadb8e536 100644
--- a/test/embedded/concurrency-typed-throws.swift
+++ b/test/embedded/concurrency-typed-throws.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -enable-experimental-feature Embedded -target %target-cpu-apple-macos14 -parse-as-library %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%target-cpu-apple-macos -lswift_Concurrency -lswift_ConcurrencyDefaultExecutor -dead_strip
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -parse-as-library %s -c -o %t/a.o
+// RUN: %target-clang %t/a.o -o %t/a.out -L%swift_obj_root/lib/swift/embedded/%module-target-triple %target-clang-resource-dir-opt -lswift_Concurrency %target-swift-default-executor-opt -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
-// REQUIRES: OS=macosx
+// REQUIRES: OS=macosx || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 import _Concurrency
diff --git a/test/embedded/coroutines-and-testing.swift b/test/embedded/coroutines-and-testing.swift
new file mode 100644
index 0000000000000..c1857829b6854
--- /dev/null
+++ b/test/embedded/coroutines-and-testing.swift
@@ -0,0 +1,19 @@
+// Make sure this can be compiled without any errors
+
+// RUN: %target-swift-frontend %s -emit-ir -o /dev/null -enable-experimental-feature Embedded -enable-testing
+// RUN: %target-swift-frontend %s -emit-ir -o /dev/null -enable-experimental-feature Embedded -enable-testing -no-allocations
+
+
+// REQUIRES: VENDOR=apple
+// REQUIRES: OS=macosx
+// REQUIRES: swift_feature_Embedded
+
+public protocol P {
+  var storage: UInt32 { get set }
+}
+
+struct MyStruct: P {
+  var storage: UInt32
+}
+
+
diff --git a/test/embedded/custom-print.swift b/test/embedded/custom-print.swift
index c12087c31a387..2c1f649685fed 100644
--- a/test/embedded/custom-print.swift
+++ b/test/embedded/custom-print.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -enable-experimental-feature Extern -enable-experimental-feature Embedded -enforce-exclusivity=none %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out
+// RUN: %target-clang %target-clang-resource-dir-opt %t/a.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
diff --git a/test/embedded/cxx-import-reference.swift b/test/embedded/cxx-import-reference.swift
new file mode 100644
index 0000000000000..f02986d7f804a
--- /dev/null
+++ b/test/embedded/cxx-import-reference.swift
@@ -0,0 +1,42 @@
+// RUN: %empty-directory(%t)
+// RUN: %{python} %utils/split_file.py -o %t %s
+
+// RUN: %target-swift-frontend -I %t %t/Main.swift -enable-experimental-feature Embedded -cxx-interoperability-mode=default -c -o %t/a.o -Rmodule-loading
+
+// REQUIRES: swift_feature_Embedded
+
+// BEGIN header.h
+
+class C;
+
+void retainC(C * _Nonnull obj);
+void releaseC(C * _Nonnull obj);
+
+class C {
+public:
+  C(const C &) = delete;
+  C() {};
+  
+  virtual void foo();
+
+  static C * _Nonnull create () __attribute__((swift_attr("returns_retained")));
+}
+__attribute__((swift_attr("import_reference")))
+__attribute__((swift_attr("retain:retainC")))
+__attribute__((swift_attr("release:releaseC")));
+
+// BEGIN module.modulemap
+
+module MyModule {
+  header "header.h"
+}
+
+// BEGIN Main.swift
+
+import MyModule
+
+public func test()
+{
+  let c =  C.create()
+  c.foo()
+}
diff --git a/test/embedded/deinit-noncopyable-2.swift b/test/embedded/deinit-noncopyable-2.swift
new file mode 100644
index 0000000000000..f998e505da233
--- /dev/null
+++ b/test/embedded/deinit-noncopyable-2.swift
@@ -0,0 +1,42 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -g -enable-experimental-feature Embedded -c -o %t/main.o
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Embedded
+
+// https://github.com/swiftlang/swift/issues/72627 - crash with noncopyable
+// generic deinit.
+
+final class Box<T: ~Copyable> {
+  var value: T
+  init(_ value: consuming T) {
+   self.value = value
+  }
+}
+
+struct ListNode<Element: ~Copyable>: ~Copyable {
+    typealias Link = Box<ListNode<Element>>?
+
+    var element: Element
+    var next: Link
+}
+
+struct List<Element: ~Copyable>: ~Copyable {
+  typealias Link = Box<ListNode<Element>>?
+  
+  var head: Link = nil
+
+  init(head: consuming Link = nil) {
+    self.head = head
+  }
+
+  mutating func push(_ element: consuming Element) {
+    self = Self(head: Box(ListNode(element: element, next: self.head)))
+  }
+}
+
+public func main() {
+  var myList = List<Int>()
+  myList.push(1)
+  let _ = consume myList
+}
+
diff --git a/test/embedded/deinit-noncopyable.swift b/test/embedded/deinit-noncopyable.swift
new file mode 100644
index 0000000000000..2aa2b448c1989
--- /dev/null
+++ b/test/embedded/deinit-noncopyable.swift
@@ -0,0 +1,164 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend %t/Library.swift -g -enable-experimental-feature Embedded -enable-experimental-feature Lifetimes -c -parse-as-library -o %t/Library.o -emit-module
+// RUN: %target-swift-frontend -I %t %t/Application.swift -g -enable-experimental-feature Embedded -enable-experimental-feature Lifetimes -c -o %t/main.o
+// RUN: %target-clang %target-clang-resource-dir-opt %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-run %t/a.out | %FileCheck %s
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_Embedded
+// REQUIRES: swift_feature_Lifetimes
+
+//--- Library.swift
+@safe public struct UniqueBuffer<Element: ~Copyable>: ~Copyable {
+    @usableFromInline
+    let buffer: UnsafeMutableBufferPointer<Element>
+
+    private init(_uninitializedCount count: Int) {
+      buffer = UnsafeMutableBufferPointer.allocate(capacity: count)
+    }
+
+    @inline(__always)
+    @_alwaysEmitIntoClient
+    deinit {
+        buffer.deinitialize().deallocate()
+    }
+
+    /// Allocate a new buffer with `count` elements and call the given `body` function to produce an element
+    /// for each entry.
+    public init<E>(count: Int, body: (Int) throws(E) -> Element) throws(E) {
+        self.init(_uninitializedCount: count)
+
+        for i in 0..<count {
+            do throws(E) {
+                buffer[i] = try body(i)
+            } catch {
+                // The closure threw an error. We need to deinitialize every element we've initialized up to this point.
+                for j in 0 ..< i {
+                    buffer.deinitializeElement(at: j)
+                }
+
+                throw error
+            }
+        }
+    }
+
+    /// The number of elements in the buffer.
+    public var count: Int { buffer.count }
+
+    /// Access the ith element in the buffer.
+    public subscript(_ i: Index) -> Element {
+        unsafeAddress {
+            precondition(i >= 0 && i < count)
+            return UnsafePointer(buffer.baseAddress! + i)
+        }
+
+        unsafeMutableAddress {
+            precondition(i >= 0 && i < count)
+            return buffer.baseAddress! + i
+        }
+    }
+
+    /// Index into this data structure.
+    public typealias Index = Int
+
+    /// Indices into this buffer.
+    public var indices: Range<Int> { 0..<count }
+
+    /// Produce a span covering all of the elements in the buffer.
+    public var span: Span<Element> {
+        @_lifetime(borrow self)
+        borrowing get {
+            buffer.span
+        }
+    }
+
+    /// Produce a mutable span covering all of the elements in the buffer.
+    public var mutableSpan: MutableSpan<Element> {
+        @_lifetime(&self)
+        mutating get {
+            buffer.mutableSpan
+        }
+    }
+
+    /// Run the body closure with an unsafe buffer pointer referencing the storage of this unique buffer.
+    /// 
+    /// Clients should prefer the `mutableSpan` property, which provides memory safety.
+    @unsafe public mutating func withUnsafeMutableBufferPointer<T, E>(_ body: (UnsafeMutableBufferPointer<Element>) throws(E) -> T) throws(E) -> T {
+        try body(buffer)
+    }
+}
+
+extension UniqueBuffer {
+    /// Allocate a buffer with `count` elements, all of which are a copy of `Element`.
+    public init(repeating element: Element, count: Int) {
+        self.init(_uninitializedCount: count)
+        buffer.initialize(repeating: element)
+    }
+
+    /// Allocate a buffer that contains a copy of the elements in the given collection.
+    public init(_ collection: some Collection<Element>) {
+        self.init(_uninitializedCount: collection.count)
+        _ = buffer.initialize(fromContentsOf: collection)
+    }
+}
+
+public enum BufferWrapper: ~Copyable {
+case buffer(UniqueBuffer<Int>)
+case empty
+}
+
+extension BufferWrapper {
+  public init(repeating: Int, count: Int) {
+    self = .buffer(UniqueBuffer<Int>(repeating: 17, count: 15))
+  }
+
+  public var count: Int {
+    switch self {
+    case .buffer(let unique): unique.count
+    case .empty: 0
+    }
+  }
+
+  public subscript(index: Int) -> Int {
+    switch self {
+    case .buffer(let unique): unique[index]
+    case .empty: fatalError("boom")
+    }
+  }
+}
+
+public struct BufferOfWrappers: ~Copyable {
+  let inner: UniqueBuffer<BufferWrapper>
+
+  public init() {
+    inner = UniqueBuffer(count: 17) { index in
+      .empty
+    }
+  }
+
+  public func countEm() -> Int {
+    return inner.count
+  }
+}
+
+//--- Application.swift
+import Library
+
+func test() {
+  let bufferWrapper = BufferWrapper(repeating: 17, count: 16)
+  var sum = 0
+  for i in 0..<bufferWrapper.count {
+    sum += bufferWrapper[i]
+  }
+  print(bufferWrapper.count)
+  print(sum)
+
+  let anotherBuffer = BufferOfWrappers()
+  print(anotherBuffer.countEm())
+}
+
+test()
+// CHECK: 15
+// CHECK: 17
+
diff --git a/test/embedded/deinit-release.swift b/test/embedded/deinit-release.swift
index 059c87d99c64b..cdb50cdfcceea 100644
--- a/test/embedded/deinit-release.swift
+++ b/test/embedded/deinit-release.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -enable-experimental-feature Embedded -O -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-clang %target-clang-resource-dir-opt %t/main.o -o %t/a.out -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
diff --git a/test/embedded/deinit-release2.swift b/test/embedded/deinit-release2.swift
index 8683254177bbd..a54edd8801810 100644
--- a/test/embedded/deinit-release2.swift
+++ b/test/embedded/deinit-release2.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -enable-experimental-feature Embedded -O -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-clang %target-clang-resource-dir-opt %t/main.o -o %t/a.out -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
diff --git a/test/embedded/dependencies-random.swift b/test/embedded/dependencies-random.swift
index 3ecf39ee662e4..122f80770b36f 100644
--- a/test/embedded/dependencies-random.swift
+++ b/test/embedded/dependencies-random.swift
@@ -1,18 +1,21 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -parse-as-library -enable-experimental-feature Embedded %s -c -o %t/a.o
+// RUN: %target-swift-frontend -parse-as-library -enable-experimental-feature Embedded -enable-experimental-feature Extern %s -c -o %t/a.o
 
-// RUN: grep DEP\: %s | sed 's#// DEP\: ##' | sort > %t/allowed-dependencies.txt
+// RUN: if [[ %target-os =~ "wasi" ]]; then pattern="DEP\:\|DEP-WASM\:"; else pattern="DEP\:"; fi; grep "$pattern" %s | sed "s#// .*\: ##" | sort > %t/allowed-dependencies.txt
 
-// Linux/ELF doesn't use the "_" prefix in symbol mangling.
-// RUN: if [ %target-os == "linux-gnu" ]; then sed -E -i -e 's/^_(.*)$/\1/' %t/allowed-dependencies.txt; fi
+// Linux/ELF and Wasm don't use the "_" prefix in symbol mangling.
+// RUN: if [ %target-os == "linux-gnu" ] || [[ %target-os =~ "wasi" ]]; then sed -E -i -e 's/^_(.*)$/\1/' %t/allowed-dependencies.txt; fi
 
 // RUN: %llvm-nm --undefined-only --format=just-symbols %t/a.o | sort | tee %t/actual-dependencies.txt
 
 // Fail if there is any entry in actual-dependencies.txt that's not in allowed-dependencies.txt
 // RUN: test -z "`comm -13 %t/allowed-dependencies.txt %t/actual-dependencies.txt`"
 
+// DEP-WASM: ___indirect_function_table
+// DEP-WASM: ___memory_base
 // DEP: ___stack_chk_fail
 // DEP: ___stack_chk_guard
+// DEP-WASM: ___stack_pointer
 // DEP: _arc4random_buf
 // DEP: _free
 // DEP: _memmove
@@ -22,7 +25,7 @@
 
 // RUN: %target-clang -x c -c %S/Inputs/print.c -o %t/print.o
 // RUN: %target-clang -x c -c %S/Inputs/linux-rng-support.c -o %t/linux-rng-support.o
-// RUN: %target-clang %t/a.o %t/print.o %t/linux-rng-support.o -o %t/a.out
+// RUN: %target-clang %target-clang-resource-dir-opt %t/a.o %t/print.o %t/linux-rng-support.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
@@ -30,8 +33,8 @@
 // REQUIRES: optimized_stdlib
 // UNSUPPORTED: OS=linux-gnu && CPU=aarch64
 
-// REQUIRES: rdar121923818
 // REQUIRES: swift_feature_Embedded
+// REQUIRES: swift_feature_Extern
 
 @_extern(c, "putchar")
 @discardableResult
diff --git a/test/embedded/devirt_generic_class_methods.swift b/test/embedded/devirt_generic_class_methods.swift
new file mode 100644
index 0000000000000..b5edba61e5a26
--- /dev/null
+++ b/test/embedded/devirt_generic_class_methods.swift
@@ -0,0 +1,22 @@
+// RUN: %target-swift-frontend %s -parse-as-library -enable-experimental-feature Embedded -Xllvm -sil-disable-pass=mandatory-inlining -emit-ir -o /dev/null
+
+// REQUIRES: swift_feature_Embedded
+
+
+// Check that the compiler doesn't crash
+
+public class Base<T> {
+  func foo(_ t: T) -> T {
+    return t
+  }
+}
+
+@_transparent
+func callee(_ i: Int, _ c: Base<Int>) -> Int {
+  return c.foo(i)
+}
+
+public func testit(_ i : Int) -> Int {
+  return callee(i, Base<Int>())
+}
+
diff --git a/test/embedded/dynamic-self.swift b/test/embedded/dynamic-self.swift
index 9e72762b2a9f1..63b55f328062a 100644
--- a/test/embedded/dynamic-self.swift
+++ b/test/embedded/dynamic-self.swift
@@ -18,4 +18,4 @@ struct Main {
      }
 }
 
-// CHECK: define {{.*}}@main(
+// CHECK: define {{.*}}@{{_*}}main{{.*}}(
diff --git a/test/embedded/empty-box.swift b/test/embedded/empty-box.swift
new file mode 100644
index 0000000000000..8428f4b66b60c
--- /dev/null
+++ b/test/embedded/empty-box.swift
@@ -0,0 +1,24 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -wmo) | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_Embedded
+
+public struct ZeroSizedStruct {}
+
+var escape: (()->())? = nil
+
+public func sink<T>(t: inout T) {
+
+}
+
+public func foo() {
+    var s = ZeroSizedStruct() 
+    escape = {
+        sink(t: &s)
+    }
+}
+
+foo()
+print("OK!")
+// CHECK: OK!
diff --git a/test/embedded/existential-class-bound1.swift b/test/embedded/existential-class-bound1.swift
index cf54e86f7743d..9cb21dd1bd9f6 100644
--- a/test/embedded/existential-class-bound1.swift
+++ b/test/embedded/existential-class-bound1.swift
@@ -10,6 +10,7 @@
 protocol ClassBound: AnyObject {
     func foo()
     func bar()
+    func predicate() -> Bool
 }
 
 class MyClass {}
@@ -230,6 +231,22 @@ func testP4() -> any P4 {
   return C4(t: K4(x: 437))
 }
 
+var gg: any ClassBound = MyClass()
+
+extension ClassBound {
+  public func isSame(_ rhs: some ClassBound) -> Bool {
+    if let rhs = rhs as? Self {
+      return rhs.predicate()
+    }
+    return false 
+  }
+  public func predicate() -> Bool { true }
+}
+
+@inline(never)
+func testIsSame(_ p: any ClassBound) -> Bool {
+  return p.isSame(gg)
+}
 
 
 @main
@@ -261,6 +278,11 @@ struct Main {
         // CHECK: 102
         testP4().foo()
         // CHECK: 437
+
+        print(testIsSame(MyClass()))
+        // CHECK: true
+        print(testIsSame(MyOtherClass()))
+        // CHECK: false
     }
 }
 
diff --git a/test/embedded/existential-class-bound5.swift b/test/embedded/existential-class-bound5.swift
index 3361f96179a2c..26af1b762356f 100644
--- a/test/embedded/existential-class-bound5.swift
+++ b/test/embedded/existential-class-bound5.swift
@@ -22,8 +22,7 @@ func test(existential: any ClassBound) {
 }
 
 func test(existential: any NotClassBound) {
-    existential.foo() // expected-error {{cannot use a value of protocol type in embedded Swift}}
-                      // expected-note@+3 {{called from here}}
+    existential.foo() // expected-error {{cannot use a value of protocol type 'any NotClassBound' in embedded Swift}}
 }
 
 @main
diff --git a/test/embedded/existential-class-bound7.swift b/test/embedded/existential-class-bound7.swift
index 01d8499d4a3d7..a5ce7c47bb5dd 100644
--- a/test/embedded/existential-class-bound7.swift
+++ b/test/embedded/existential-class-bound7.swift
@@ -9,20 +9,20 @@ public protocol P: AnyObject {
 }
 
 final public class Class: P {
-  public func foo<T>(t: T) {}
+  public func foo<T>(t: T) {} // expected-error {{a protocol type cannot contain a generic method 'foo(t:)' in embedded Swift}}
 }
 
 
 public func testClass() -> P {
-  return Class() // expected-error {{an existential type cannot contain a generic method 'foo(t:)' in embedded Swift}}
+  return Class() // expected-note {{protocol type value created here}}
 }
 
 final public class GenClass<X>: P {
-  public func foo<T>(t: T) {}
+  public func foo<T>(t: T) {} // expected-error {{a protocol type cannot contain a generic method 'foo(t:)' in embedded Swift}}
 }
 
 
 public func testGenClass() -> P {
-  return GenClass<Int>() // expected-error {{an existential type cannot contain a generic method 'foo(t:)' in embedded Swift}}
+  return GenClass<Int>() // expected-note {{protocol type value created here}}
 }
 
diff --git a/test/embedded/existential-class-bound8.swift b/test/embedded/existential-class-bound8.swift
index c1329cc6a3c02..a7caeb301f2a2 100644
--- a/test/embedded/existential-class-bound8.swift
+++ b/test/embedded/existential-class-bound8.swift
@@ -9,7 +9,11 @@
 
 // BEGIN MyModule.swift
 
-public protocol ClassBound: AnyObject {
+public protocol Base: AnyObject {
+    func bar()
+}
+
+public protocol ClassBound: Base {
     func foo()
 }
 
@@ -18,6 +22,7 @@ class MyGenericClass<T> {
     init(typ: String) { self.typ = typ }
 }
 extension MyGenericClass: ClassBound {
+    func bar() { print("MyGenericClass<\(typ)>.bar()") }
     func foo() { print("MyGenericClass<\(typ)>.foo()") }
 }
 
@@ -32,3 +37,5 @@ import MyModule
 var arr: [any ClassBound] = [factory()]
 arr[0].foo()
 // CHECK: MyGenericClass<String>.foo()
+arr[0].foo()
+// CHECK: MyGenericClass<String>.bar()
diff --git a/test/embedded/existential-composition.swift b/test/embedded/existential-composition.swift
index f1264e1c5a8c1..b241c54063085 100644
--- a/test/embedded/existential-composition.swift
+++ b/test/embedded/existential-composition.swift
@@ -22,7 +22,6 @@ func test(existential: any ClassBound & OtherProtocol) {
 @main
 struct Main {
   static func main() {
-    test(existential: MyClass()) // expected-error {{cannot use a value of protocol type 'any ClassBound & OtherProtocol' in embedded Swift}}
-                                 // expected-note@-4 {{called from here}}
+    test(existential: MyClass()) // expected-error {{cannot use a value of protocol type 'any OtherProtocol' in embedded Swift}}
   }
 }
diff --git a/test/embedded/existential-default-method.swift b/test/embedded/existential-default-method.swift
new file mode 100644
index 0000000000000..7d24545002d06
--- /dev/null
+++ b/test/embedded/existential-default-method.swift
@@ -0,0 +1,101 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo) | %FileCheck %s
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo -O) | %FileCheck %s
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo -Osize) | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: optimized_stdlib
+// REQUIRES: swift_feature_Embedded
+
+// Simple case
+
+public protocol ProtocolWithDefaultMethod: AnyObject {
+  func getInt() -> Int
+}
+
+extension ProtocolWithDefaultMethod {
+  public func getInt() -> Int {
+    return 42
+  }
+}
+
+public class Class: ProtocolWithDefaultMethod {
+}
+
+public class GenClass<T>: ProtocolWithDefaultMethod {
+}
+
+func test(existential: any ProtocolWithDefaultMethod) {
+  print(existential.getInt())
+}
+
+// Test that we specialize for the correct derived class
+
+class C {
+  class func g() -> Int {
+    return 1
+  }
+}
+
+class D: C {
+  override class func g() -> Int {
+    return 2
+  }
+}
+
+protocol P: AnyObject {
+  static func g() -> Int
+  func test() -> Int
+}
+
+extension P {
+  func test() -> Int {
+    Self.g()
+  }
+}
+
+extension C: P {}
+
+func createDerived() -> P {
+  return D()
+}
+
+// Test that we don't end up in an infinite recursion loop
+
+public protocol RecursiveProto: AnyObject {
+  associatedtype T: RecursiveProto
+  func getInt() -> Int
+  func getT() -> T
+}
+
+extension RecursiveProto {
+  public func getInt() -> Int {
+    return 27
+  }
+}
+
+public class RecursiveClass: RecursiveProto {
+  public typealias T = RecursiveClass
+  public func getT() -> RecursiveClass {
+    return self
+  }
+}
+
+func testRecursive(existential: any RecursiveProto) {
+  print(existential.getT().getInt())
+}
+
+
+@main
+struct Main {
+  static func main() {
+    // CHECK: 42
+    test(existential: Class())
+    // CHECK: 42
+    test(existential: GenClass<Int>())
+    // CHECK: 2
+    print(createDerived().test())
+    // CHECK: 27
+    testRecursive(existential: RecursiveClass())
+  }
+}
+
diff --git a/test/embedded/existential-generic-error.swift b/test/embedded/existential-generic-error.swift
new file mode 100644
index 0000000000000..aa865fbb03089
--- /dev/null
+++ b/test/embedded/existential-generic-error.swift
@@ -0,0 +1,18 @@
+// RUN: %target-swift-emit-ir -parse-as-library -module-name main -verify %s -enable-experimental-feature Embedded -wmo
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: optimized_stdlib
+// REQUIRES: swift_feature_Embedded
+
+public protocol MyProtocol: AnyObject {
+    func foo<T: BinaryInteger>(ptr: UnsafeMutableRawPointer?, value: T)
+}
+
+func test_some(p: some MyProtocol) {
+  p.foo(ptr: nil, value: 0) // expected-error {{a protocol type cannot contain a generic method 'foo(ptr:value:)' in embedded Swift}}
+}
+
+public func test_any(p: any MyProtocol) {
+  test_some(p: p)
+  // expected-warning@-1{{cannot use generic global function 'test_some(p:)' on a value of type 'any MyProtocol' in Embedded Swift}}
+}
diff --git a/test/embedded/extensions.swift b/test/embedded/extensions.swift
index a05675a372607..495e288d32935 100644
--- a/test/embedded/extensions.swift
+++ b/test/embedded/extensions.swift
@@ -19,6 +19,6 @@ struct MyStruct {}
 
 extension MyStruct: MyProtocol {}
 
-// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}(i32 %0, ptr %1)
 // CHECK-NOT: MyStruct
 // CHECK-NOT: MyProtocol
diff --git a/test/embedded/failable-crash.swift b/test/embedded/failable-crash.swift
index 8f95c7c48e9e9..8724c61301b54 100644
--- a/test/embedded/failable-crash.swift
+++ b/test/embedded/failable-crash.swift
@@ -16,4 +16,4 @@ public class MyClass<T> {
     }
 }
 
-// CHECK: define {{.*}}@main(
+// CHECK: define {{.*}}@{{_*}}main{{.*}}(
diff --git a/test/embedded/float-abi-hard.swift b/test/embedded/float-abi-hard.swift
index ef35933eb2516..f410efd604984 100644
--- a/test/embedded/float-abi-hard.swift
+++ b/test/embedded/float-abi-hard.swift
@@ -4,6 +4,7 @@
 // RUN: %target-swift-emit-ir %t/Main.swift -import-bridging-header %t/BridgingHeader.h -parse-as-library -enable-experimental-feature Embedded -wmo \
 // RUN:  -target armv7em-none-none-eabi -Xcc -mthumb -Xcc -mcpu=cortex-m7 -Xcc -mfloat-abi=hard -Xcc -mfpu=fpv5-sp-d16 -Xcc -D__FPU_USED=1 -Xcc -falign-functions=16
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: CODEGENERATOR=ARM
diff --git a/test/embedded/fragile-reference.swift b/test/embedded/fragile-reference.swift
index 9ee8c4e6d8575..07b21a9272a10 100644
--- a/test/embedded/fragile-reference.swift
+++ b/test/embedded/fragile-reference.swift
@@ -1,5 +1,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target arm64-apple-none-macho -module-name main -parse-as-library -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: CODEGENERATOR=ARM
 // REQUIRES: embedded_stdlib_cross_compiling
@@ -17,5 +19,5 @@ enum MyEnum: UInt8 {
     case a = 0
 }
 
-// CHECK: define {{.*}}@main(
+// CHECK: define {{.*}}@{{_*}}main{{.*}}(
 
diff --git a/test/embedded/generic-error.swift b/test/embedded/generic-error.swift
new file mode 100644
index 0000000000000..774687d58e3f8
--- /dev/null
+++ b/test/embedded/generic-error.swift
@@ -0,0 +1,25 @@
+// RUN: %target-swift-emit-ir -parse-as-library -module-name main -verify %s -enable-experimental-feature Embedded -swift-version 5 -wmo -o /dev/null
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: optimized_stdlib
+// REQUIRES: swift_feature_Embedded
+
+// We don't support calling a default witness method (which is generic) with dynamic self.
+
+public protocol P {
+  init(x: Int)
+}
+
+extension P {
+  init(y: Int) {
+    self.init(x: y)
+  }
+}
+
+public class C: P {
+  public required init(x: Int) {}
+
+  public convenience init(z: Int) {
+    self.init(y: z)  // expected-error {{cannot call an initializer or static method, which is defined as default protocol method, from a class method or initializer}}
+  }
+}
diff --git a/test/embedded/generic-specialization.swift b/test/embedded/generic-specialization.swift
new file mode 100644
index 0000000000000..03b97b45a6215
--- /dev/null
+++ b/test/embedded/generic-specialization.swift
@@ -0,0 +1,13 @@
+// RUN: %target-run-simple-swift(   -enable-experimental-feature Embedded -wmo -runtime-compatibility-version none) | %FileCheck %s
+// RUN: %target-run-simple-swift(-O -enable-experimental-feature Embedded -wmo -runtime-compatibility-version none) | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_Embedded
+
+func f<V>(_ a: [V]) -> [String] {
+    return a.indices.map { String($0 /* as Int*/) }  // adding `as Int` makes it compile
+}
+
+// CHECK: 0
+print(f(["A"]).joined())
+
diff --git a/test/embedded/hello.swift b/test/embedded/hello.swift
index f39e89a486437..0d970472f7e73 100644
--- a/test/embedded/hello.swift
+++ b/test/embedded/hello.swift
@@ -2,7 +2,7 @@
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: executable_test
-// REQUIRES: OS=macosx || OS=linux-gnu || OS=none-eabi || OS=none-elf
+// REQUIRES: OS=macosx || OS=linux-gnu || OS=none-eabi || OS=none-elf || OS=wasip1
 // REQUIRES: swift_feature_Embedded
 
 print("Hello, Embedded Swift!")
diff --git a/test/embedded/keypath-crash.swift b/test/embedded/keypath-crash.swift
index e33d24ce7e0f9..6487a9f537d05 100644
--- a/test/embedded/keypath-crash.swift
+++ b/test/embedded/keypath-crash.swift
@@ -12,7 +12,7 @@ public struct Binding<Value> {
     self.wrappedValue = get()
   }
 
-  subscript<Subject>(dynamicMember keyPath: WritableKeyPath<Value, Subject>) -> Binding<Subject> {
+  public subscript<Subject>(dynamicMember keyPath: WritableKeyPath<Value, Subject>) -> Binding<Subject> {
     get { fatalError() }
   }
 }
@@ -20,7 +20,7 @@ public struct Binding<Value> {
 
 public struct State<Wrapped> {
   public var wrappedValue: Wrapped
-  
+
   public init(wrappedValue: Wrapped) {
     self.wrappedValue = wrappedValue
   }
@@ -51,4 +51,4 @@ public struct S<T> {
    }
 }
 
-// CHECK: define {{.*}}@main(
+// CHECK: define {{.*}}@{{_*}}main{{.*}}(
diff --git a/test/embedded/keypaths2.swift b/test/embedded/keypaths2.swift
index 691962f344409..1d743f9509a40 100644
--- a/test/embedded/keypaths2.swift
+++ b/test/embedded/keypaths2.swift
@@ -12,7 +12,7 @@ public struct Box<T>: ~Copyable {
         self.value = UnsafeMutablePointer<T>.allocate(capacity: 1)
     }
 
-    subscript<U>(dynamicMember member: WritableKeyPath<T, U>) -> U {
+    public subscript<U>(dynamicMember member: WritableKeyPath<T, U>) -> U {
         @_transparent
         get { return self.value.pointer(to: member)!.pointee }
 
@@ -20,6 +20,7 @@ public struct Box<T>: ~Copyable {
         set { self.value.pointer(to: member)!.pointee = newValue }
     }
 
+    @usableFromInline
     var value: UnsafeMutablePointer<T>
 }
 
diff --git a/test/embedded/linkage-custom-entry-point.swift b/test/embedded/linkage-custom-entry-point.swift
index 19ac84d7f58d6..95ee1aef14557 100644
--- a/test/embedded/linkage-custom-entry-point.swift
+++ b/test/embedded/linkage-custom-entry-point.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend %s -module-name Application -parse-as-library -entry-point-function-name Application_main -mergeable-symbols    -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
-// RUN: %target-swift-frontend %s -module-name Application -parse-as-library -entry-point-function-name Application_main -mergeable-symbols -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend %s -module-name Application -parse-as-library -entry-point-function-name Application_main    -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend %s -module-name Application -parse-as-library -entry-point-function-name Application_main -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_Embedded
diff --git a/test/embedded/linkage-mergeable-dead-strip.swift b/test/embedded/linkage-mergeable-dead-strip.swift
index 66dc820e691a5..14d32767dda66 100644
--- a/test/embedded/linkage-mergeable-dead-strip.swift
+++ b/test/embedded/linkage-mergeable-dead-strip.swift
@@ -1,8 +1,8 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend -enable-experimental-feature Embedded -enable-experimental-feature SymbolLinkageMarkers -module-name main -mergeable-symbols -O %s -emit-ir | %FileCheck %s --check-prefix=CHECK-IR
-// RUN: %target-swift-frontend -enable-experimental-feature Embedded -enable-experimental-feature SymbolLinkageMarkers -module-name main -mergeable-symbols -O %s -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out -dead_strip
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -enable-experimental-feature SymbolLinkageMarkers -module-name main -O %s -emit-ir | %FileCheck %s --check-prefix=CHECK-IR
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -enable-experimental-feature SymbolLinkageMarkers -module-name main -O %s -c -o %t/a.o
+// RUN: %target-clang %target-clang-resource-dir-opt %t/a.o -o %t/a.out -dead_strip
 // RUN: %llvm-nm --defined-only --format=just-symbols --demangle %t/a.out | sort | %FileCheck %s --check-prefix=CHECK-NM
 // RUN: %target-run %t/a.out | %FileCheck %s
 
@@ -16,8 +16,8 @@ public func a_this_is_unused() { }
 @_used
 public func b_this_is_unused_but_explicitly_retained() { }
 
-// CHECK-IR: define weak_odr {{.*}}@"$e4main16a_this_is_unusedyyF"()
-// CHECK-IR: define weak_odr {{.*}}@"$e4main40b_this_is_unused_but_explicitly_retainedyyF"()
+// CHECK-IR: define {{.*}}@"$e4main16a_this_is_unusedyyF"()
+// CHECK-IR: define {{.*}}@"$e4main40b_this_is_unused_but_explicitly_retainedyyF"()
 
 // CHECK-NM-NOT: $e4main14this_is_unusedyyF
 // CHECK-NM: $e4main40b_this_is_unused_but_explicitly_retainedyyF
diff --git a/test/embedded/linkage-mergeable.swift b/test/embedded/linkage-mergeable.swift
index 8748407a44587..1e9f3ca913093 100644
--- a/test/embedded/linkage-mergeable.swift
+++ b/test/embedded/linkage-mergeable.swift
@@ -1,9 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
 
-// RUN: %target-swift-frontend -mergeable-symbols -c -emit-module -o %t/MyModule.o %t/MyModule.swift   -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-swift-frontend -mergeable-symbols -c              -o %t/a.o        %t/Main.swift -I %t -enable-experimental-feature Embedded
-// RUN: %target-clang %t/a.o %t/MyModule.o -o %t/a.out
+// RUN: %target-swift-frontend -c -emit-module -o %t/MyModule.o %t/MyModule.swift   -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c              -o %t/a.o        %t/Main.swift -I %t -enable-experimental-feature Embedded
+// RUN: %target-clang %target-clang-resource-dir-opt %t/a.o %t/MyModule.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
diff --git a/test/embedded/linkage-mergeable2.swift b/test/embedded/linkage-mergeable2.swift
index fac25086b705e..46e0482d65a02 100644
--- a/test/embedded/linkage-mergeable2.swift
+++ b/test/embedded/linkage-mergeable2.swift
@@ -1,9 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
 
-// RUN: %target-swift-frontend -mergeable-symbols -O -c -emit-module -o %t/MyModule.o %t/MyModule.swift   -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-swift-frontend -mergeable-symbols -O -c              -o %t/a.o        %t/Main.swift -I %t -enable-experimental-feature Embedded
-// RUN: %target-clang %t/a.o %t/MyModule.o -o %t/a.out
+// RUN: %target-swift-frontend -O -c -emit-module -o %t/MyModule.o %t/MyModule.swift   -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -O -c              -o %t/a.o        %t/Main.swift -I %t -enable-experimental-feature Embedded
+// RUN: %target-clang %target-clang-resource-dir-opt %t/a.o %t/MyModule.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
diff --git a/test/embedded/linkage-mergeable3.swift b/test/embedded/linkage-mergeable3.swift
index e8d3b81cdcdd2..c65158746fdf9 100644
--- a/test/embedded/linkage-mergeable3.swift
+++ b/test/embedded/linkage-mergeable3.swift
@@ -1,9 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
 
-// RUN: %target-swift-frontend -mergeable-symbols -num-threads 2 -O -c -emit-module -o %t/MyModule.o             %t/MyModule.swift                   -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-swift-frontend -mergeable-symbols -num-threads 2 -O -c              -o %t/MainA.o -o %t/MainB.o  %t/MainA.swift %t/MainB.swift -I %t -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-clang %t/MainA.o %t/MainB.o %t/MyModule.o -o %t/a.out
+// RUN: %target-swift-frontend -num-threads 2 -O -c -emit-module -o %t/MyModule.o             %t/MyModule.swift                   -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -num-threads 2 -O -c              -o %t/MainA.o -o %t/MainB.o  %t/MainA.swift %t/MainB.swift -I %t -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-clang %target-clang-resource-dir-opt %t/MainA.o %t/MainB.o %t/MyModule.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
diff --git a/test/embedded/linkage-mergeable4.swift b/test/embedded/linkage-mergeable4.swift
index a668717a9cec7..6b2ae0e6da13e 100644
--- a/test/embedded/linkage-mergeable4.swift
+++ b/test/embedded/linkage-mergeable4.swift
@@ -1,9 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s
 
-// RUN: %target-swift-frontend -mergeable-symbols -num-threads 2 -O -c -emit-module -o %t/MyModule.o             %t/MyModule.swift                   -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-swift-frontend -mergeable-symbols -num-threads 2 -O -c              -o %t/MainA.o -o %t/MainB.o  %t/MainA.swift %t/MainB.swift -I %t -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-clang %linux_rng_support_c_if_needed %t/MainA.o %t/MainB.o %t/MyModule.o -o %t/a.out
+// RUN: %target-swift-frontend -num-threads 2 -O -c -emit-module -o %t/MyModule.o             %t/MyModule.swift                   -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -num-threads 2 -O -c              -o %t/MainA.o -o %t/MainB.o  %t/MainA.swift %t/MainB.swift -I %t -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-embedded-link %target-clang-resource-dir-opt %t/MainA.o %t/MainB.o %t/MyModule.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
diff --git a/test/embedded/linkage-public-exports.swift b/test/embedded/linkage-public-exports.swift
index cd04ef45cb94d..5dd1aed3c66fb 100644
--- a/test/embedded/linkage-public-exports.swift
+++ b/test/embedded/linkage-public-exports.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend %s -mergeable-symbols    -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
-// RUN: %target-swift-frontend %s -mergeable-symbols -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend %s    -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend %s -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_Embedded
diff --git a/test/embedded/linkage/Inputs/CHeader.h b/test/embedded/linkage/Inputs/CHeader.h
new file mode 100644
index 0000000000000..d7ef0f7c265cc
--- /dev/null
+++ b/test/embedded/linkage/Inputs/CHeader.h
@@ -0,0 +1,5 @@
+typedef struct {
+  double x, y;
+} Point;
+
+Point getPoint(double x, double y);
diff --git a/test/embedded/linkage/Inputs/MyModuleExports.h b/test/embedded/linkage/Inputs/MyModuleExports.h
new file mode 100644
index 0000000000000..ab74ed6f4f450
--- /dev/null
+++ b/test/embedded/linkage/Inputs/MyModuleExports.h
@@ -0,0 +1,4 @@
+double clib_func1(void);
+double clib_func2(void);
+double clib_func3(void);
+double clib_func4(void);
diff --git a/test/embedded/linkage/Inputs/SwiftDependency.swift b/test/embedded/linkage/Inputs/SwiftDependency.swift
new file mode 100644
index 0000000000000..2fc3b1624c11b
--- /dev/null
+++ b/test/embedded/linkage/Inputs/SwiftDependency.swift
@@ -0,0 +1,7 @@
+public struct A {
+  private var string: String
+
+  public init() { self.string = "Hello" }
+
+  public func doSomething() { }
+}
diff --git a/test/embedded/linkage/Inputs/module.modulemap b/test/embedded/linkage/Inputs/module.modulemap
new file mode 100644
index 0000000000000..a1f15125ed19d
--- /dev/null
+++ b/test/embedded/linkage/Inputs/module.modulemap
@@ -0,0 +1,7 @@
+module CDependency {
+  header "CHeader.h"
+}
+
+module MyModuleExports {
+  header "MyModuleExports.h"
+}
diff --git a/test/embedded/linkage/c.swift b/test/embedded/linkage/c.swift
new file mode 100644
index 0000000000000..2edc76eac5618
--- /dev/null
+++ b/test/embedded/linkage/c.swift
@@ -0,0 +1,81 @@
+// Check that C functions are exported as needed.
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_Embedded
+// REQUIRES: swift_feature_DeferredCodeGen
+// REQUIRES: swift_feature_CDecl
+// REQUIRES: swift_feature_CImplementation
+// REQUIRES: swift_feature_SymbolLinkageMarkers
+
+// RUN: %target-swift-frontend -emit-ir -o - %s -I %S/Inputs -package-name MyPackage -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -enable-experimental-feature CDecl -enable-experimental-feature CImplementation -enable-experimental-feature SymbolLinkageMarkers -parse-as-library | %FileCheck %s
+
+import MyModuleExports
+
+// ---------------------------------------------------------------------------
+// @c / @_cdecl on > internal declarations cause symbol emission
+// ---------------------------------------------------------------------------
+
+// CHECK: define {{(protected |dllexport )?}}void @lib_publicCDeclFunc()
+@_cdecl("lib_publicCDeclFunc")
+public func f1() { }
+
+// CHECK: define {{(protected |dllexport )?}}void @lib_publicCFunc()
+@c(lib_publicCFunc)
+package func f2() { }
+
+// CHECK: define hidden void @lib_publicCDeclFunc3
+@_cdecl("lib_publicCDeclFunc3")
+internal func f3() { }
+
+// CHECK: define hidden void @lib_publicCDeclFunc4
+@c("lib_publicCDeclFunc4")
+internal func f4() { }
+
+// CHECK-NOT: lib_publicCDeclFunc5
+@_cdecl("lib_publicCDeclFunc5")
+private func f5() { }
+
+// CHECK-NOT: lib_publicCDeclFunc6
+@c("lib_publicCDeclFunc6")
+private func f6() { }
+
+// ---------------------------------------------------------------------------
+// @implementation @c / @_cdecl cause symbol emission
+// ---------------------------------------------------------------------------
+
+// CHECK: define {{(protected |dllexport )?}}double @clib_func1
+@_cdecl("clib_func1") @implementation
+public func clib_func1() -> Double { 0 }
+
+// CHECK: define {{(protected |dllexport )?}}double @clib_func2
+@c @implementation
+package func clib_func2() -> Double { 0 }
+
+// CHECK: define hidden double @clib_func3
+@_cdecl("clib_func3") @implementation
+internal func clib_func3() -> Double { 0 }
+
+// CHECK: define hidden double @clib_func4
+@c @implementation
+internal func clib_func4() -> Double { 0 }
+
+// ---------------------------------------------------------------------------
+// @_section causes symbol emission
+// ---------------------------------------------------------------------------
+
+// CHECK: define {{(protected |dllexport )?}}swiftcc void @"$e1c15symbolInSectionyyF"
+@_section("__TEXT,__mysection")
+public func symbolInSection() { }
+
+// CHECK: define hidden swiftcc void @"$e1c23internalSymbolInSectionyyF"
+@_section("__TEXT,__mysection")
+func internalSymbolInSection() { }
+
+// ---------------------------------------------------------------------------
+// @_used causes symbol emission
+// ---------------------------------------------------------------------------
+
+// CHECK: define hidden swiftcc void @"$e1c10usedSymbolyyF"
+@_used
+func usedSymbol() { }
diff --git a/test/embedded/linkage/cxx.swift b/test/embedded/linkage/cxx.swift
new file mode 100644
index 0000000000000..7390e8d123de4
--- /dev/null
+++ b/test/embedded/linkage/cxx.swift
@@ -0,0 +1,16 @@
+// Check that C++ functions are exported as needed.
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_Embedded
+// REQUIRES: swift_feature_DeferredCodeGen
+
+// RUN: %target-swift-frontend -emit-ir -o - %s -I %S/Inputs -package-name MyPackage -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library -cxx-interoperability-mode=default | %FileCheck %s
+
+// CHECK: define hidden swiftcc void @"$e3cxx2f1yyF"()
+@_expose(Cxx)
+func f1() { }
+
+// CHECK-NOT: 2f2
+@_expose(!Cxx)
+public func f2() { }
diff --git a/test/embedded/linkage/diamond.swift b/test/embedded/linkage/diamond.swift
new file mode 100644
index 0000000000000..753d035799a62
--- /dev/null
+++ b/test/embedded/linkage/diamond.swift
@@ -0,0 +1,158 @@
+// This test makes sure that we can build, link, and execute an Embedded Swift
+// application that's composed of multiple libraries. It tests various
+// combinations of "leaf" and "non-leaf" modules along the way to ensure that
+// every combination produces a working binary that is free of either missing or
+// (incorrectly) duplicated symbols. All of the modules implicitly depend on the
+// Swift standard library.
+//
+// The overall shape of the module dependencies looks like this:
+//
+//
+//                           Swift
+//                             |
+//                             |
+//                           Root
+//                          /    \
+//                         /      \
+//                     ClientA  ClientB
+//                        \        /
+//                         \      /
+//                        Application
+//
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// Test #1: Defaults for everything
+// RUN: %target-swift-frontend -c -emit-module -o %t/Root.o %t/Root.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientA.o %t/ClientA.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientB.o %t/ClientB.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/Application.o %t/Application.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-clang %target-clang-resource-dir-opt %t/Root.o %t/ClientA.o %t/ClientB.o %t/Application.o -o %t/Application
+// RUN: %target-run %t/Application | %FileCheck %s
+
+// Test #2: Root is an "intermediate" library for everything
+// RUN: %target-swift-frontend -c -emit-module -o %t/Root.o %t/Root.swift -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientA.o %t/ClientA.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientB.o %t/ClientB.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/Application.o %t/Application.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-clang %target-clang-resource-dir-opt %t/Root.o %t/ClientA.o %t/ClientB.o %t/Application.o -o %t/Application
+// RUN: %target-run %t/Application | %FileCheck %s
+
+// Test #3: ClientA as an "intermediate" library
+// RUN: %target-swift-frontend -c -emit-module -o %t/Root.o %t/Root.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientA.o %t/ClientA.swift -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientB.o %t/ClientB.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/Application.o %t/Application.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-clang %target-clang-resource-dir-opt %t/Root.o %t/ClientA.o %t/ClientB.o %t/Application.o -o %t/Application
+// RUN: %target-run %t/Application | %FileCheck %s
+
+// Test #4: Root and ClientA as "intermediate" libraries
+// RUN: %target-swift-frontend -c -emit-module -o %t/Root.o %t/Root.swift -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientA.o %t/ClientA.swift -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientB.o %t/ClientB.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/Application.o %t/Application.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-clang %target-clang-resource-dir-opt %t/Root.o %t/ClientA.o %t/ClientB.o %t/Application.o -o %t/Application
+// RUN: %target-run %t/Application | %FileCheck %s
+
+// Test #%: All "intermediate", all the time. Main drives code generation
+// RUN: %target-swift-frontend -c -emit-module -o %t/Root.o %t/Root.swift -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientA.o %t/ClientA.swift -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/ClientB.o %t/ClientB.swift -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library
+// RUN: %target-swift-frontend -c -I %t -emit-module -o %t/Application.o %t/Application.swift -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library
+// RUN: %target-clang %target-clang-resource-dir-opt %t/Root.o %t/ClientA.o %t/ClientB.o %t/Application.o -o %t/Application
+// RUN: %target-run %t/Application | %FileCheck %s
+
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_Embedded
+// REQUIRES: swift_feature_DeferredCodeGen
+
+//--- Root.swift
+struct Point {
+  var x, y: Int
+}
+
+public func enumerateByteOffsets<T>(_: T.Type) -> [Int] {
+  var array: [Int] = []
+  for i in 0..<MemoryLayout<T>.size {
+    array.append(i)
+  }
+  return array
+}
+
+public func getPointOffsets() -> [Int] {
+  enumerateByteOffsets(Point.self)
+}
+
+public class PointClass {
+  public var x, y: Int
+
+  public init(x: Int, y: Int) {
+    self.x = x
+    self.y = y
+  }
+}
+
+public protocol Reflectable: AnyObject {
+  func reflect()
+}
+
+extension PointClass: Reflectable {
+  public func reflect() {
+    swap(&x, &y)
+  }
+}
+
+//--- ClientA.swift
+import Root
+
+public struct Color {
+  var red: UInt8
+  var green: UInt8
+  var blue: UInt8
+}
+
+public func getPointAndColorOffsets() -> [Int] {
+  getPointOffsets() + enumerateByteOffsets(Color.self)
+}
+
+public func getReflectableA() -> any AnyObject & Reflectable {
+  return PointClass(x: 5, y: 5)
+}
+
+//--- ClientB.swift
+import Root
+
+struct Point3D {
+  var x, y, z: Double
+}
+
+public func getExtraPoint3DOffsets() -> [Int] {
+  let pointOffsets = getPointOffsets()
+  let point3DOffsets = enumerateByteOffsets(Point3D.self)
+  return Array(point3DOffsets[pointOffsets.count...])
+}
+
+public func getReflectableB() -> any AnyObject & Reflectable {
+  return PointClass(x: 5, y: 5)
+}
+
+//--- Application.swift
+import ClientA
+import ClientB
+
+@main
+struct Main {
+  static func main() {
+    let pointAndColorOffsets = getPointAndColorOffsets()
+    let extraColor3DOffsets = getExtraPoint3DOffsets()
+    print(pointAndColorOffsets.count)
+    print(extraColor3DOffsets.count)
+
+    let reflected = [getReflectableA(), getReflectableB()]
+    // CHECK: DONE
+    print("DONE")
+  }
+}
diff --git a/test/embedded/linkage/implementation_only_hiding.swift b/test/embedded/linkage/implementation_only_hiding.swift
new file mode 100644
index 0000000000000..079c6f02cc7ca
--- /dev/null
+++ b/test/embedded/linkage/implementation_only_hiding.swift
@@ -0,0 +1,73 @@
+// This elaborate test ensures that @_implementationOnly with Embedded Swift
+// can hide some dependencies if you are very, very careful.
+
+// RUN: %empty-directory(%t)
+// RUN: mkdir -p %t/Dependencies
+// RUN: mkdir -p %t/Files
+// RUN: mkdir -p %t/Modules
+
+// Copy Swift file + C header + module map into a separate directory we'll use
+// when building the module whose implementation we want to hide.
+// RUN: cp %S/Inputs/SwiftDependency.swift %t/Dependencies/
+// RUN: cp %S/Inputs/CHeader.h %t/Dependencies/
+// RUN: cp %S/Inputs/module.modulemap %t/Dependencies/
+
+// RUN: split-file %s %t/Files
+
+// Compile the Swift dependencies into that same location.
+// RUN: %target-swift-frontend -parse-as-library -emit-module %t/Dependencies/SwiftDependency.swift -enable-experimental-feature Embedded -o %t/Dependencies/SwiftDependency.swiftmodule
+
+// Build the library (which is supposed to encapsulate those dependencies)
+// against the dependencies.
+// RUN: %target-swift-frontend -parse-as-library -emit-module %t/Files/Library.swift -enable-experimental-feature Embedded -I %t/Dependencies/ -o %t/Modules/Library.swiftmodule
+
+// Remove the dependencies so there is no way we can find them later.
+// RUN: rm -rf %t/Dependencies
+
+// Build the application against the library. This is expected to work because
+// @_neverEmitIntoClient hides the body of test().
+// RUN: %target-swift-frontend -emit-ir -parse-as-library %t/Files/Application.swift -enable-experimental-feature Embedded -I %t/Modules -o %t/Application.ir
+
+// Build the application against the library, but intentionally trigger
+// deserialization of some serialized SIL that refers to an implementation-only
+// dependency. Right now, these fail spectacularly. Over time, we want them to
+// become compile-time errors or start working.
+// RUN: not --crash %target-swift-frontend -emit-ir -parse-as-library %t/Files/Application.swift -enable-experimental-feature Embedded -I %t/Modules -o %t/Application.ir -DBAD_C_USAGE
+// RUN: not --crash %target-swift-frontend -emit-ir -parse-as-library %t/Files/Application.swift -enable-experimental-feature Embedded -I %t/Modules -o %t/Application.ir -DBAD_SWIFT_USAGE
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Embedded
+
+//--- Library.swift
+@_implementationOnly import CDependency
+@_implementationOnly import SwiftDependency
+
+@_neverEmitIntoClient
+public func test() {
+  _ = getPoint(3.14159, 2.71828)
+  A().doSomething()
+}
+
+public func badCLibraryUsage() {
+  _ = getPoint(3.14159, 2.71828)
+}
+
+public func badSwiftLibraryUsage() {
+  A().doSomething()
+}
+
+//--- Application.swift
+
+import Library
+
+public func useTest() {
+  test()
+
+#if BAD_C_USAGE
+  badCLibraryUsage()
+#endif
+
+#if BAD_SWIFT_USAGE
+  badSwiftLibraryUsage()
+#endif
+}
diff --git a/test/embedded/linkage/leaf_application.swift b/test/embedded/linkage/leaf_application.swift
new file mode 100644
index 0000000000000..40c8a83b0fb30
--- /dev/null
+++ b/test/embedded/linkage/leaf_application.swift
@@ -0,0 +1,119 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// Library module
+
+// SIL checking
+// RUN: %target-swift-frontend %t/Library.swift -parse-as-library -entry-point-function-name Library_main -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -emit-sil -emit-module-path %t/Modules/Library.swiftmodule -o - | %FileCheck -check-prefix LIBRARY-SIL %s
+
+// IR checking to ensure we get the right weak symbols.
+// RUN: %target-swift-frontend %t/Library.swift -parse-as-library -entry-point-function-name Library_main -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -emit-ir -o - | %FileCheck -check-prefix LIBRARY-IR --dump-input-filter all %s
+
+// Application module
+
+// RUN: %target-swift-frontend %t/Application.swift -I %t/Modules -parse-as-library -entry-point-function-name Application_main -enable-experimental-feature Embedded -emit-sil -o - | %FileCheck -check-prefix APPLICATION-SIL %s
+
+// RUN: %target-swift-frontend %t/Application.swift -I %t/Modules -parse-as-library -entry-point-function-name Application_main -enable-experimental-feature Embedded -emit-ir -o - | %FileCheck -check-prefix APPLICATION-IR --dump-input-filter all %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Embedded
+// REQUIRES: swift_feature_DeferredCodeGen
+
+//--- Library.swift
+
+// LIBRARY-IR: @"$e7Library10PointClassCN" = linkonce_odr {{.*}}global
+
+// Never referenced.
+// LIBRARY-IR-NOT: @"$es23_swiftEmptyArrayStorageSi_S3itvp" = linkonce_odr {{(protected |dllexport )?}}global
+
+// Note: referenced by swift_allocEmptyBox.
+// LIBRARY-IR: @"$es16_emptyBoxStorageSi_Sitvp" = linkonce_odr {{(protected |dllexport )?}}global
+
+// LIBRARY-IR-NOT: define {{.*}}@"$e7Library5helloSaySiGyF"()
+public func hello() -> [Int] {
+  getArray()
+}
+
+// LIBRARY-IR-NOT: define {{.*}} @"$e7Library8getArraySaySiGyF"()
+public func getArray() -> [Int] {
+  throughInternal()
+}
+
+// LIBRARY-IR-NOT: define {{.*}} @"$e7Library15throughInternalSaySiGyF"()
+func throughInternal() -> [Int] {
+  throughPrivate()
+}
+
+// LIBRARY-IR-NOT: define {{.*}} @"$e7Library14throughPrivate
+private func throughPrivate() -> [Int] {
+  [5, 6, 7]
+}
+
+// LIBRARY-IR-NOT: unnecessary
+public func unnecessary() -> Int64 { 5 }
+
+// LIBRARY-IR: define {{.*}} @"$e7Library14unusedYetThere
+@_neverEmitIntoClient
+public func unusedYetThere() -> Int64 { 5 }
+
+public class PointClass {
+  public var x, y: Int
+
+  public init(x: Int, y: Int) {
+    self.x = x
+    self.y = y
+  }
+}
+
+public protocol Reflectable: AnyObject {
+  func reflect()
+}
+
+// LIBRARY-IR: define linkonce_odr hidden swiftcc void @"$es4swapyyxz_xztlFSi_Tg5"
+// LIBRARY-IR: define linkonce_odr hidden swiftcc void @"$e7Library10PointClassCAA11ReflectableA2aDP7reflectyyFTW"
+
+extension PointClass: Reflectable {
+  public func reflect() {
+    swap(&x, &y)
+  }
+}
+
+// LIBRARY-IR: define {{.*}} @"$e7Library18createsExistentialAA11Reflectable_pyF"()
+@_neverEmitIntoClient
+public func createsExistential() -> any Reflectable {
+  return PointClass(x: 5, y: 5)
+}
+
+// LIBRARY-IR-NOT: define swiftcc
+// LIBRARY-IR-NOT: define hidden swiftcc
+
+// LIBRARY-IR-NOT: define {{.*}} @"$es27_allocateUninitializedArrayySayxG_BptBwlFSi_Tg5"
+
+// LIBRARY-SIL: sil @$e7Library5helloSaySiGyF
+// LIBRARY-SIL: sil @$e7Library8getArraySaySiGyF : $@convention(thin) () -> @owned Array<Int> {
+
+//--- Application.swift
+import Library
+
+public func testMe() {
+  _ = hello()
+  _ = getArray()
+}
+
+// APPLICATION-IR: define {{(protected |dllexport )?}}swiftcc void @"$e11Application6testMeyyF"()
+
+// APPLICATION-SIL: sil public_external @$e7Library5helloSaySiGyF : $@convention(thin) () -> @owned Array<Int> {
+// APPLICATION-IR: define linkonce_odr hidden swiftcc ptr @"$e7Library5helloSaySiGyF"()
+
+// APPLICATION-SIL: sil public_external @$e7Library8getArraySaySiGyF : $@convention(thin) () -> @owned Array<Int> {
+// APPLICATION-IR: define linkonce_odr hidden swiftcc ptr @"$e7Library8getArraySaySiGyF"()
+
+// APPLICATION-IR: define {{(protected |dllexport )?}}i32 @Application_main
+
+// APPLICATION-IR: define linkonce_odr hidden swiftcc { ptr, ptr } @"$es27_allocateUninitializedArrayySayxG_BptBwlFSi_Tg5"
+
+@main
+struct Main {
+  static func main() {
+  }
+}
diff --git a/test/embedded/linkage/leaf_library.swift b/test/embedded/linkage/leaf_library.swift
new file mode 100644
index 0000000000000..41baf678c4e0b
--- /dev/null
+++ b/test/embedded/linkage/leaf_library.swift
@@ -0,0 +1,73 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// Library module
+
+// SIL checking
+// RUN: %target-swift-frontend %t/Library.swift -parse-as-library -entry-point-function-name Library_main -enable-experimental-feature Embedded -emit-sil -emit-module-path %t/Modules/Library.swiftmodule -o - | %FileCheck -check-prefix LIBRARY-SIL %s
+
+// IR checking to ensure we get the right weak symbols.
+// RUN: %target-swift-frontend %t/Library.swift -parse-as-library -entry-point-function-name Library_main -enable-experimental-feature Embedded -emit-ir -o - | %FileCheck -check-prefix LIBRARY-IR --dump-input-filter all %s
+
+// Application module
+
+// RUN: %target-swift-frontend %t/Application.swift -I %t/Modules -parse-as-library -entry-point-function-name Application_main  -enable-experimental-feature Embedded -emit-sil -o - | %FileCheck -check-prefix APPLICATION-SIL %s
+
+// RUN: %target-swift-frontend %t/Application.swift -I %t/Modules -parse-as-library -entry-point-function-name Application_main -enable-experimental-feature Embedded -emit-ir -o - | %FileCheck -check-prefix APPLICATION-IR --dump-input-filter all %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Embedded
+
+//--- Library.swift
+
+// LIBRARY-IR: define {{(protected |dllexport )?}}swiftcc ptr @"$e7Library5helloSaySiGyF"()
+public func hello() -> [Int] {
+  getArray()
+}
+
+// LIBRARY-IR: define {{(protected |dllexport )?}}swiftcc ptr @"$e7Library8getArraySaySiGyF"()
+public func getArray() -> [Int] {
+  throughInternal()
+}
+
+// LIBRARY-IR: define {{(protected |dllexport )?}}swiftcc ptr @"$e7Library15throughInternalSaySiGyF"()
+func throughInternal() -> [Int] {
+  throughPrivate()
+}
+
+// LIBRARY-IR: define {{(protected |dllexport )?}}swiftcc ptr @"$e7Library14throughPrivate33_
+private func throughPrivate() -> [Int] {
+  [5, 6, 7]
+}
+
+// LIBRARY-IR: define linkonce_odr hidden swiftcc { ptr, ptr } @"$es27_allocateUninitializedArrayySayxG_BptBwlFSi_Tg5"
+
+// LIBRARY-IR: define {{(protected |dllexport )?}}swiftcc i64 @"$e7Library11unnecessarys5Int64VyF"()
+public func unnecessary() -> Int64 { 5 }
+
+// LIBRARY-SIL: sil @$e7Library5helloSaySiGyF
+// LIBRARY-SIL: sil @$e7Library8getArraySaySiGyF : $@convention(thin) () -> @owned Array<Int> {
+
+//--- Application.swift
+import Library
+
+public func testMe() {
+  _ = hello()
+  _ = getArray()
+}
+
+// APPLICATION-IR: define {{(protected |dllexport )?}}swiftcc void @"$e11Application6testMeyyF"()
+
+// APPLICATION-SIL: sil public_external @$e7Library5helloSaySiGyF : $@convention(thin) () -> @owned Array<Int> {
+// APPLICATION-IR: define linkonce_odr hidden swiftcc ptr @"$e7Library5helloSaySiGyF"()
+
+// APPLICATION-SIL: sil public_external @$e7Library8getArraySaySiGyF : $@convention(thin) () -> @owned Array<Int> {
+// APPLICATION-IR: define linkonce_odr hidden swiftcc ptr @"$e7Library8getArraySaySiGyF"()
+
+// APPLICATION-IR: define {{(protected |dllexport )?}}i32 @Application_main
+@main
+struct Main {
+  static func main() {
+  }
+}
+
diff --git a/test/embedded/linkage/never_emit_into_client.swift b/test/embedded/linkage/never_emit_into_client.swift
new file mode 100644
index 0000000000000..83bdf8f5ce388
--- /dev/null
+++ b/test/embedded/linkage/never_emit_into_client.swift
@@ -0,0 +1,81 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// Library module
+
+// SIL checking
+// RUN: %target-swift-frontend %t/Library.swift -parse-as-library -entry-point-function-name Library_main -enable-experimental-feature Embedded -emit-sil -emit-module-path %t/Modules/Library.swiftmodule -o - | %FileCheck -check-prefix LIBRARY-SIL %s
+
+// IR checking to ensure we get the right weak symbols.
+// RUN: %target-swift-frontend %t/Library.swift -parse-as-library -entry-point-function-name Library_main -enable-experimental-feature Embedded -emit-ir -o - | %FileCheck -check-prefix LIBRARY-IR --dump-input-filter all %s
+
+// Application module
+
+// RUN: %target-swift-frontend %t/Application.swift -I %t/Modules -parse-as-library -entry-point-function-name Application_main -enable-experimental-feature Embedded -emit-sil -o - | %FileCheck -check-prefix APPLICATION-SIL %s
+
+// RUN: %target-swift-frontend %t/Application.swift -I %t/Modules -parse-as-library -entry-point-function-name Application_main -enable-experimental-feature Embedded -emit-ir -o - | %FileCheck -check-prefix APPLICATION-IR %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Embedded
+
+//--- Library.swift
+
+// LIBRARY-IR: define {{(protected |dllexport )?}}swiftcc ptr @"$e7Library5helloSaySiGyF"()
+@_neverEmitIntoClient
+public func hello() -> [Int] {
+  getArray()
+}
+
+// LIBRARY-IR: define {{(protected |dllexport )?}}swiftcc ptr @"$e7Library8getArraySaySiGyF"()
+public func getArray() -> [Int] {
+  throughInternal()
+}
+
+// LIBRARY-IR: define {{(protected |dllexport )?}}swiftcc ptr @"$e7Library15throughInternalSaySiGyF"()
+func throughInternal() -> [Int] {
+  throughPrivate()
+}
+
+// LIBRARY-IR: define {{(protected |dllexport )?}}swiftcc ptr @"$e7Library14throughPrivate
+private func throughPrivate() -> [Int] {
+  [5, 6, 7]
+}
+
+// LIBRARY-IR-NOT: unnecessary
+public func unnecessary() -> Int { 5 }
+
+// LIBRARY-IR: define linkonce_odr hidden swiftcc { ptr, ptr } @"$es27_allocateUninitializedArrayySayxG_BptBwlFSi_Tg5"
+
+// LIBRARY-SIL: sil @$e7Library5helloSaySiGyF
+// LIBRARY-SIL: sil @$e7Library8getArraySaySiGyF : $@convention(thin) () -> @owned Array<Int> {
+
+//--- Application.swift
+import Library
+
+@_neverEmitIntoClient
+public func testMe() {
+  _ = hello()
+  _ = getArray()
+}
+
+// Note: "hello" is emitted only into the object file, so there is no definition
+// here.
+
+// APPLICATION-SIL: sil @$e7Library5helloSaySiGyF : $@convention(thin) () -> @owned Array<Int>{{$}}
+// APPLICATION-IR: declare swiftcc ptr @"$e7Library5helloSaySiGyF"()
+
+// Note: "getArray" is not @_neverEmitIntoClient, so it's definition is
+// available.
+
+// APPLICATION-SIL: sil public_external @$e7Library8getArraySaySiGyF : $@convention(thin) () -> @owned Array<Int> {
+// APPLICATION-IR: define linkonce_odr hidden swiftcc ptr @"$e7Library8getArraySaySiGyF"()
+
+// APPLICATION-IR: define{{.*}}@Application_main
+@main
+struct Main {
+  static func main() {
+  }
+}
+
+// APPLICATION-IR: define linkonce_odr hidden swiftcc { ptr, ptr } @"$es27_allocateUninitializedArrayySayxG_BptBwlFSi_Tg5"
+
diff --git a/test/embedded/lit.local.cfg b/test/embedded/lit.local.cfg
index 59469ee61f89e..7e6ca0a0deaf1 100644
--- a/test/embedded/lit.local.cfg
+++ b/test/embedded/lit.local.cfg
@@ -4,6 +4,7 @@ config.substitutions = list(config.substitutions)
 # A handful of test setup tweaks that we want for *all* Embedded Swift tests (i.e. all tests in this directory):
 
 # (1) When targeting macOS, raise the deployment target to macOS 14.0 (from the default 13.0)
+config.target_clang = config.target_clang.replace("-apple-macosx13.0", "-apple-macos14")
 if config.target_sdk_name == 'macosx':
   def do_fixup(key, value):
     if isinstance(value, str):
@@ -19,7 +20,7 @@ if 'embedded_stdlib' not in config.available_features:
   config.unsupported = True
 
 # (3) Restrict Embedded Swift tests only to the currently supported set of test target OS's, skip them otherwise.
-supported_test_os_list = ["OS=macosx", "OS=linux-gnu", "OS=none-eabi", "OS=none-elf"]
+supported_test_os_list = ["OS=macosx", "OS=linux-gnu", "OS=none-eabi", "OS=none-elf", "OS=wasip1"]
 if config.available_features.intersection(set(supported_test_os_list)) == set():
   config.unsupported = True
 
@@ -29,8 +30,16 @@ config.environment = dict(config.environment)
 if 'SWIFT_USE_OLD_DRIVER' in config.environment: del config.environment['SWIFT_USE_OLD_DRIVER']
 if 'SWIFT_AVOID_WARNING_USING_OLD_DRIVER' in config.environment: del config.environment['SWIFT_AVOID_WARNING_USING_OLD_DRIVER']
 
+target_cpu = [y for (x, y) in config.substitutions if x == "%target-cpu"][0]
+target_triple = [y for (x, y) in config.substitutions if x == "%target-triple"][0]
+
 # (5) Provide some useful substitutions to simplify writing tests that work across platforms (macOS, Linux, etc.)
 if "OS=linux-gnu" in config.available_features:
-  config.substitutions.append(("%linux_rng_support_c_if_needed", "%S/Inputs/linux-rng-support.c"))
+  config.substitutions.append(("%target-embedded-link", config.target_clang + " -x c %S/Inputs/linux-rng-support.c -x none"))
+  config.substitutions.append(("%embedded-unicode-tables", f"-Xlinker {config.swift_obj_root}/lib/swift/embedded/{target_cpu}-unknown-linux-gnu/libswiftUnicodeDataTables.a"))
+elif "OS=macosx" in config.available_features:
+  config.substitutions.append(("%target-embedded-link", config.target_clang))
+  config.substitutions.append(("%embedded-unicode-tables", f"-Xlinker {config.swift_obj_root}/lib/swift/embedded/{target_cpu}-apple-macos/libswiftUnicodeDataTables.a"))
 else:
-  config.substitutions.append(("%linux_rng_support_c_if_needed", ""))
+  config.substitutions.append(("%target-embedded-link", config.target_clang))
+  config.substitutions.append(("%embedded-unicode-tables", f"-Xlinker {config.swift_obj_root}/lib/swift/embedded/{target_triple}/libswiftUnicodeDataTables.a"))
diff --git a/test/embedded/managed-buffer.swift b/test/embedded/managed-buffer.swift
index d7ae6e0660787..b133fbbb0cdad 100644
--- a/test/embedded/managed-buffer.swift
+++ b/test/embedded/managed-buffer.swift
@@ -4,7 +4,7 @@
 // REQUIRES: swift_feature_Embedded
 
 // CHECK: @"$e4main8MyBufferCN" = {{.*global.*}} <{ ptr @"$es13ManagedBufferCySis5UInt8VGN", ptr @"$e4main8MyBufferCfD{{[^"]*}}", ptr null, ptr @"$e4main8MyBufferC12_doNotCallMeACyt_tcfC{{[^"]*}}" }>
-// CHECK: @"$es13ManagedBufferCySis5UInt8VGN" = {{.*global.*}} <{ ptr null, ptr @"$es13ManagedBufferCfDSi_s5UInt8VTg5{{[^"]*}}", ptr null, ptr @"$es13ManagedBufferC12_doNotCallMeAByxq_Gyt_tcfCSi_s5UInt8VTg5{{[^"]*}}" }>
+// CHECK: @"$es13ManagedBufferCySis5UInt8VGN" = {{.*global.*}} <{ ptr null, ptr @"$es13ManagedBufferCfDSi_s5UInt8VTgq5{{[^"]*}}", ptr null, ptr @"$es13ManagedBufferC12_doNotCallMeAByxq_Gyt_tcfCSi_s5UInt8VTgq5{{[^"]*}}" }>
 final public class MyBuffer: ManagedBuffer<Int, UInt8> {
 }
 
diff --git a/test/embedded/metatypes.swift b/test/embedded/metatypes.swift
index 9f4926a2c437d..0516bfeac51c4 100644
--- a/test/embedded/metatypes.swift
+++ b/test/embedded/metatypes.swift
@@ -14,10 +14,11 @@ public func test() -> Int {
 
 func castToExistential<T>(x: T) {
   if x is any FixedWidthInteger {    // expected-error {{cannot do dynamic casting in embedded Swift}}
+    // expected-warning@-1{{cannot perform a dynamic cast to a type involving protocol 'FixedWidthInteger' in Embedded Swift}}
   }
 }
 
 public func callCastToExistential() {
-  castToExistential(x: 42)    // expected-note {{called from here}}
+  castToExistential(x: 42)    // expected-note {{generic specialization called here}}
 }
 
diff --git a/test/embedded/min-pointer-value-default-darwin.swift b/test/embedded/min-pointer-value-default-darwin.swift
new file mode 100644
index 0000000000000..3852cafda6ce0
--- /dev/null
+++ b/test/embedded/min-pointer-value-default-darwin.swift
@@ -0,0 +1,22 @@
+
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Embedded -O -min-valid-pointer-value=0x1000  | %FileCheck %s
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Embedded -O | %FileCheck %s
+
+// REQUIRES: OS=macosx
+// REQUIRES: swift_feature_Embedded
+
+public func testit(_ s: S?) -> Bool {
+  return s != nil
+}
+
+class C {}
+
+public struct S {
+  var a = InlineArray<57, UInt8>(repeating: 0)
+  var b = C()
+  var c = InlineArray<49, UInt8>(repeating: 0)
+}
+
+// CHECK-LABEL: define {{.*}} @"$e4main1SVSgWOg"(ptr %0)
+// CHECK:         icmp {{.*}}, 4095
+// CHECK-LABEL: }
diff --git a/test/embedded/min-pointer-value-option.swift b/test/embedded/min-pointer-value-option.swift
new file mode 100644
index 0000000000000..e6d6bff8a80b2
--- /dev/null
+++ b/test/embedded/min-pointer-value-option.swift
@@ -0,0 +1,21 @@
+
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Embedded -O -min-valid-pointer-value=0x200  | %FileCheck %s
+
+// REQUIRES: OS=macosx || OS=linux-gnu
+// REQUIRES: swift_feature_Embedded
+
+public func testit(_ s: S?) -> Bool {
+  return s != nil
+}
+
+class C {}
+
+public struct S {
+  var a = InlineArray<57, UInt8>(repeating: 0)
+  var b = C()
+  var c = InlineArray<49, UInt8>(repeating: 0)
+}
+
+// CHECK-LABEL: define {{.*}} @"$e4main1SVSgWOg"(ptr %0)
+// CHECK:         icmp {{.*}}, 511
+// CHECK-LABEL: }
diff --git a/test/embedded/mirror.swift b/test/embedded/mirror.swift
index 6578381fd30b2..432d3e33d172b 100644
--- a/test/embedded/mirror.swift
+++ b/test/embedded/mirror.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-emit-ir -verify %s -enable-experimental-feature Embedded -wmo
+// RUN: %target-swift-emit-ir -verify -verify-ignore-unrelated %s -enable-experimental-feature Embedded -wmo
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
diff --git a/test/embedded/modules-empty-object.swift b/test/embedded/modules-empty-object.swift
index 5cbbf0b4d49b5..baf59fa11f5d8 100644
--- a/test/embedded/modules-empty-object.swift
+++ b/test/embedded/modules-empty-object.swift
@@ -5,7 +5,7 @@
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -c -I%t -parse-as-library %t/MyModuleB.swift -o %t/MyModuleB.o -emit-module -emit-module-path %t/MyModuleB.swiftmodule -emit-empty-object-file
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -c -I%t -parse-as-library %t/MyModuleC.swift -o %t/MyModuleC.o -emit-module -emit-module-path %t/MyModuleC.swiftmodule -emit-empty-object-file
 // RUN: %target-swift-frontend -enable-experimental-feature Embedded -c -I%t %t/Main.swift -o %t/Main.o
-// RUN: %target-clang %t/Main.o %t/MyModuleA.o %t/MyModuleB.o %t/MyModuleC.o -o %t/a.out
+// RUN: %target-clang %target-clang-resource-dir-opt %t/Main.o %t/MyModuleA.o %t/MyModuleB.o %t/MyModuleC.o -o %t/a.out
 // RUN: %target-run %t/a.out
 
 // REQUIRES: swift_in_compiler
diff --git a/test/embedded/modules-globals.swift b/test/embedded/modules-globals.swift
index 88cbd3c841779..45913b7bf986f 100644
--- a/test/embedded/modules-globals.swift
+++ b/test/embedded/modules-globals.swift
@@ -33,4 +33,4 @@ public func main() {
 // CHECK: @"$e4Main022global_in_client_used_c1_D0Sivp" = {{.*}}global %TSi zeroinitializer
 // CHECK: @"$e4Main024global_in_client_unused_c1_D0Sivp" = {{.*}}global %TSi zeroinitializer
 // CHECK: @"$e8MyModule022global_in_module_used_d1_E0Sivp" = {{.*}}global %TSi zeroinitializer
-// CHECK: @"$e8MyModule024global_in_module_unused_d1_E0Sivp" = {{.*}}global %TSi zeroinitializer
+// CHECK-NOT: @"$e8MyModule024global_in_module_unused_d1_E0Sivp" = {{.*}}global %TSi zeroinitializer
diff --git a/test/embedded/modules-used.swift b/test/embedded/modules-used.swift
index 21dd1341b4a37..6e653a8eafd23 100644
--- a/test/embedded/modules-used.swift
+++ b/test/embedded/modules-used.swift
@@ -45,7 +45,7 @@ struct Main {
 }
 
 // CHECK-SIL:      // i_am_not_referenced
-// CHECK-SIL-NEXT: sil_global [serialized] [let] @$e8MyModule19i_am_not_referencedSivp : $Int = {
+// CHECK-SIL-NEXT: sil_global [serialized] [let] [used] @$e8MyModule19i_am_not_referencedSivp : $Int = {
 
 // CHECK: count: 1
 // CHECK: mysection[0]: 42
diff --git a/test/embedded/modules-used2.swift b/test/embedded/modules-used2.swift
index d5a52fe3b3365..d94162b3a2543 100644
--- a/test/embedded/modules-used2.swift
+++ b/test/embedded/modules-used2.swift
@@ -4,7 +4,7 @@
 // RUN: %target-swift-frontend -enable-experimental-feature SymbolLinkageMarkers -enable-experimental-feature Embedded -parse-as-library -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift
 // RUN: %target-swift-frontend -enable-experimental-feature SymbolLinkageMarkers -enable-experimental-feature Embedded -parse-as-library -I %t %t/Main.swift -emit-sil | %FileCheck %s --check-prefix CHECK-SIL
 // RUN: %target-swift-frontend -enable-experimental-feature SymbolLinkageMarkers -enable-experimental-feature Embedded -parse-as-library -I %t %t/Main.swift -c -o %t/a.o
-// RUN: %target-clang %t/a.o -o %t/a.out
+// RUN: %target-clang %target-clang-resource-dir-opt %t/a.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
@@ -30,10 +30,10 @@ func foo() {
 import MyModule
 
 // CHECK-SIL:      // main()
-// CHECK-SIL-NEXT: sil @$e8MyModule4mains5Int32VyF : $@convention(thin) () -> Int32 {
+// CHECK-SIL-NEXT: sil [used] @$e8MyModule4mains5Int32VyF : $@convention(thin) () -> Int32 {
 // CHECK-SIL: 	   // main
-// CHECK-SIL-NEXT: sil [thunk] @main : $@convention(c) () -> Int32
+// CHECK-SIL-NEXT: sil [thunk] [used] @main : $@convention(c) () -> Int32
 // CHECK-SIL:      // foo()
-// CHECK-SIL-NEXT: sil @$e8MyModule3fooyyF : $@convention(thin) () -> () {
+// CHECK-SIL-NEXT: sil [used] @$e8MyModule3fooyyF : $@convention(thin) () -> () {
 
 // CHECK: main in a submodule
diff --git a/test/embedded/multi-module-debug-info.swift b/test/embedded/multi-module-debug-info.swift
new file mode 100644
index 0000000000000..458b091537369
--- /dev/null
+++ b/test/embedded/multi-module-debug-info.swift
@@ -0,0 +1,35 @@
+// RUN: %empty-directory(%t)
+// RUN: %{python} %utils/split_file.py -o %t %s
+
+// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t %t/Main.swift -enable-experimental-feature Embedded -verify -verify-ignore-unrelated -o /dev/null
+
+// REQUIRES: OS=macosx || OS=linux-gnu
+// REQUIRES: swift_feature_Embedded
+
+// BEGIN MyModule.swift
+
+public struct MyError: Error {
+}
+
+@inline(never)
+public func foo<T>(_ t: T) throws {
+  throw MyError() // expected-error {{cannot use a value of protocol type 'any Error' in embedded Swift}}
+}
+
+@inline(never)
+public func callit<T>(_ t: T) {
+  do {
+    try foo(t)
+  } catch {
+  }
+}
+
+// BEGIN Main.swift
+
+import MyModule
+
+public func testit() {
+  callit(27) // expected-note {{generic specialization called here}}
+}
+
diff --git a/test/embedded/no-allocations-print.swift b/test/embedded/no-allocations-print.swift
index 6b4ebb3ea448e..ae3270463bd12 100644
--- a/test/embedded/no-allocations-print.swift
+++ b/test/embedded/no-allocations-print.swift
@@ -3,6 +3,7 @@
 // RUN: %target-swift-emit-ir -target armv7-apple-none-macho -no-allocations %s -enable-experimental-feature Embedded
 // RUN: %target-swift-emit-ir -target arm64-apple-none-macho -no-allocations %s -enable-experimental-feature Embedded
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: CODEGENERATOR=ARM
diff --git a/test/embedded/no-allocations.swift b/test/embedded/no-allocations.swift
index 080b0f8a3af7a..13d0ffb2cfe64 100644
--- a/test/embedded/no-allocations.swift
+++ b/test/embedded/no-allocations.swift
@@ -9,7 +9,7 @@
 
 public class X {} // expected-error {{cannot use allocating type 'X' in -no-allocations mode}}
 public func use_a_class() -> X {
-	let x = X() // expected-note {{called from here}}
+	let x = X() // expected-note {{instance of type created here}}
 	return x
 }
 
diff --git a/test/embedded/once-dependent.swift b/test/embedded/once-dependent.swift
index 3978b2c14e1a2..b66cd5dca4cac 100644
--- a/test/embedded/once-dependent.swift
+++ b/test/embedded/once-dependent.swift
@@ -1,5 +1,5 @@
 // RUN: %target-swift-frontend %s -parse-as-library -enable-experimental-feature Embedded -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-clang %target-clang-resource-dir-opt %t/main.o -o %t/a.out -dead_strip
 // RUN: %target-run %t/a.out | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
@@ -9,7 +9,7 @@
 
 public struct MyStructA {
   static var singleton = MyStructA()
-  
+
   init() {
     print("MyStructA.init")
     _ = MyStructB.singleton
@@ -19,7 +19,7 @@ public struct MyStructA {
 
 public struct MyStructB {
   static var singleton = MyStructB()
-  
+
   init() {
     print("MyStructB.init")
     _ = MyStructC.singleton
@@ -29,7 +29,7 @@ public struct MyStructB {
 
 public struct MyStructC {
   static var singleton = MyStructC()
-  
+
   init() {
     print("MyStructC.init")
     print("MyStructC.init done")
diff --git a/test/embedded/optionset2.swift b/test/embedded/optionset2.swift
index 59c976872fa9a..babe9b6fe15a4 100644
--- a/test/embedded/optionset2.swift
+++ b/test/embedded/optionset2.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: CODEGENERATOR=ARM
@@ -31,4 +32,4 @@ struct ShippingOptions: MyOptionSet {
 var s = ShippingOptions(rawValue: 42)
 print(s.isEmpty)
 
-// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}(i32 %0, ptr %1)
diff --git a/test/embedded/osize-genericspecializer.swift b/test/embedded/osize-genericspecializer.swift
index ff7bd1ca5af65..6057efb497309 100644
--- a/test/embedded/osize-genericspecializer.swift
+++ b/test/embedded/osize-genericspecializer.swift
@@ -15,4 +15,4 @@ public func baz<T>(n: T) {
     let x: ContiguousArray<Int> = .init(repeating: 0, count: 1)
 }
 
-// CHECK: define {{.*}}@main(
+// CHECK: define {{.*}}@{{_*}}main{{.*}}(
diff --git a/test/embedded/osize-releasedevirt.swift b/test/embedded/osize-releasedevirt.swift
index 9ef0fac78ae39..cb266de5f7343 100644
--- a/test/embedded/osize-releasedevirt.swift
+++ b/test/embedded/osize-releasedevirt.swift
@@ -11,4 +11,4 @@ public func foo() {
 func bar(_: UnsafePointer<UInt?>) {
 }
 
-// CHECK: define {{.*}}@main(
+// CHECK: define {{.*}}@{{_*}}main{{.*}}(
diff --git a/test/embedded/ouroboros-bug.swift b/test/embedded/ouroboros-bug.swift
index 08472ab80c216..7bceb38af6a76 100644
--- a/test/embedded/ouroboros-bug.swift
+++ b/test/embedded/ouroboros-bug.swift
@@ -6,6 +6,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -assert-config Debug -Osize -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target arm64-apple-none-macho -assert-config Debug -Osize -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: CODEGENERATOR=ARM
@@ -18,4 +19,4 @@
 public func test() {}
 test()
 
-// CHECK: define {{.*}}i32 @main
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}
diff --git a/test/embedded/restrictions.swift b/test/embedded/restrictions.swift
new file mode 100644
index 0000000000000..4d00ff92a435e
--- /dev/null
+++ b/test/embedded/restrictions.swift
@@ -0,0 +1,157 @@
+// RUN: %target-typecheck-verify-swift -Wwarning EmbeddedRestrictions -verify-additional-prefix nonembedded-
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature Embedded -verify-additional-prefix embedded-
+// RUN: %target-swift-frontend -typecheck %s -suppress-warnings -enable-experimental-feature Embedded -DSUPPRESS_WEAK
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Embedded
+
+// ---------------------------------------------------------------------------
+// Untyped throws
+// ---------------------------------------------------------------------------
+
+enum MyError: Error {
+case failed
+}
+
+// expected-warning@+1{{untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'}}{{28-28=(<#thrown error type#>)}}
+func untypedThrows() throws { }
+
+// expected-warning@+1{{untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'}}{{41-41=(<#thrown error type#>)}}
+func rethrowingFunction(param: () throws -> Void) rethrows { }
+
+// expected-warning@+1{{untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'}}{{29-29=(<#thrown error type#>)}}
+typealias FnType = () throws -> Void
+
+func untypedThrowsInBody() {
+  // expected-warning@+1{{untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'}}{{12-12=(<#thrown error type#>)}}
+  do throws {
+    throw MyError.failed
+  } catch {
+  }
+
+  // expected-warning@+1{{untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'}}{{19-19=(<#thrown error type#>)}}
+  _ = { (x) throws in x + 1 }
+}
+
+struct SomeStruct {
+  // expected-warning@+1{{untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'}}{{16-16=(<#thrown error type#>)}}
+  init() throws { }
+
+  var value: Int {
+  // expected-warning@+1{{untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'}}{{15-15=(<#thrown error type#>)}}
+    get throws {
+      0
+    }
+  }
+}
+
+// ---------------------------------------------------------------------------
+// weak/unowned references
+// ---------------------------------------------------------------------------
+
+// Note: this have always been an error in Embedded Swift. Make sure they stay
+// that way, but are emitted as warnings when the restrictions are enabled.
+
+public class MyClass { }
+
+public struct MyStruct {
+  #if !SUPPRESS_WEAK
+  var normalVar: MyClass
+  weak var weakVar: MyClass? // expected-nonembedded-warning {{attribute 'weak' cannot be used in Embedded Swift}}
+  // expected-embedded-error@-1 {{attribute 'weak' cannot be used in Embedded Swift}}
+
+  unowned var unownedVar: MyClass // expected-nonembedded-warning {{attribute 'unowned' cannot be used in Embedded Swift}}
+  // expected-embedded-error @-1{{attribute 'unowned' cannot be used in Embedded Swift}}
+  #endif
+
+  unowned(unsafe) var unownedUnsafe: MyClass
+}
+
+// ---------------------------------------------------------------------------
+// generic, non-final functions
+// ---------------------------------------------------------------------------
+
+protocol P { }
+
+class MyGenericClass<T> {
+  func f<U>(value: U) { } // expected-warning{{generic instance method 'f(value:)' in a class must be 'final' in Embedded Swift}}
+  func g() { }
+  class func h() where T: P { } // expected-warning{{generic class method 'h()' in a class must be 'final' in Embedded Swift}}
+
+  init<U>(value: U) { } // okay, can be directly called
+
+  required init() { } // non-generic is okay
+
+  required init<V>(something: V) { } // expected-warning{{generic initializer 'init(something:)' in a class cannot be 'required' in Embedded Swift}}
+}
+
+// ---------------------------------------------------------------------------
+// generic functions on existentials
+// ---------------------------------------------------------------------------
+
+public protocol Q {
+  func f<T>(_ value: T)
+  func okay()
+}
+
+extension Q {
+  public func g<T>(_ value: T) {
+    f(value)
+  }
+
+  public mutating func h<T>(_ value: T) {
+    f(value)
+  }
+}
+
+public func existentials(q: any AnyObject & Q, i: Int) {
+  q.okay()
+  q.f(i) // expected-warning{{cannot use generic instance method 'f' on a value of type 'any AnyObject & Q' in Embedded Swift}}
+
+  q.g(i) // expected-warning{{cannot use generic instance method 'g' on a value of type 'any AnyObject & Q' in Embedded Swift}}
+
+  var qm = q
+  qm.h(i) // expected-warning{{cannot use generic instance method 'h' on a value of type 'any AnyObject & Q' in Embedded Swift}}
+}
+
+// ---------------------------------------------------------------------------
+// Dynamic casting restrictions
+// ---------------------------------------------------------------------------
+
+class ConformsToQ: Q {
+  final func f<T>(_ value: T) { }
+  func okay() { }
+}
+
+func dynamicCasting(object: AnyObject, cq: ConformsToQ) {
+  // expected-warning@+1{{cannot perform a dynamic cast to a type involving protocol 'Q' in Embedded Swift}}
+  if let q = object as? any AnyObject & Q {
+    _ = q
+  }
+
+  // expected-warning@+1{{cannot perform a dynamic cast to a type involving protocol 'Q' in Embedded Swift}}
+  if object is any AnyObject & Q { }
+
+  // expected-warning@+1{{cannot perform a dynamic cast to a type involving protocol 'Q' in Embedded Swift}}
+  _ = object as! AnyObject & Q
+
+  _ = cq as AnyObject & Q
+}
+
+// ---------------------------------------------------------------------------
+// #if handling to suppress diagnostics for non-Embedded-only code
+// ---------------------------------------------------------------------------
+
+#if $Embedded
+
+// expected-embedded-warning@+1{{untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'}}{{31-31=(<#thrown error type#>)}}
+func stillProblematic() throws { }
+
+#else
+
+func notProblematicAtAll() throws { }
+
+#endif
+
+#if !hasFeature(Embedded)
+func stillNotProblematicAtAll() throws { }
+#endif
diff --git a/test/embedded/specialize-opt-none.swift b/test/embedded/specialize-opt-none.swift
index 64b633cdba2f1..165e1c4e53c85 100644
--- a/test/embedded/specialize-opt-none.swift
+++ b/test/embedded/specialize-opt-none.swift
@@ -19,4 +19,4 @@ public func test() {
 // CHECK: sil hidden [Onone] @$s4main8MyStructV3fooyyF : $@convention(method) <T> (MyStruct<T>) -> () {
 
 // EMBEDDED: // specialized MyStruct.foo()
-// EMBEDDED: sil [Onone] @$e4main8MyStructV3fooyyFAA1XV_Tg5 : $@convention(method) (MyStruct<X>) -> () {
+// EMBEDDED: sil shared [Onone] @$e4main8MyStructV3fooyyFAA1XV_Tg5 : $@convention(method) (MyStruct<X>) -> () {
diff --git a/test/embedded/static-object-non-darwin.swift b/test/embedded/static-object-non-darwin.swift
index 462f4c73cc9f0..93d14a5aa05b9 100644
--- a/test/embedded/static-object-non-darwin.swift
+++ b/test/embedded/static-object-non-darwin.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target armv7em-none-none-eabi -parse-as-library -module-name main -O -emit-ir %s -enable-experimental-feature Embedded -Xllvm -link-embedded-runtime=0 | %FileCheck %s
 // RUN: %target-swift-frontend -target armv7em-none-none-eabi -parse-as-library -module-name main -Osize -emit-ir %s -enable-experimental-feature Embedded -Xllvm -link-embedded-runtime=0 | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: CODEGENERATOR=ARM
diff --git a/test/embedded/stdlib-array.swift b/test/embedded/stdlib-array.swift
index 9657921f5aea8..476c736092832 100644
--- a/test/embedded/stdlib-array.swift
+++ b/test/embedded/stdlib-array.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: CODEGENERATOR=ARM
@@ -33,4 +34,4 @@ public func test() {
 
 test()
 
-// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}(i32 %0, ptr %1)
diff --git a/test/embedded/stdlib-basic.swift b/test/embedded/stdlib-basic.swift
index 2fa2f7e3e1d00..3e0c61420490f 100644
--- a/test/embedded/stdlib-basic.swift
+++ b/test/embedded/stdlib-basic.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: CODEGENERATOR=ARM
 // REQUIRES: embedded_stdlib_cross_compiling
@@ -46,7 +47,7 @@ public func checks(n: Int) {
   if n < 0 { assertionFailure("with message") }
 }
 
-// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}(i32 %0, ptr %1)
 // CHECK: define {{.*}}i1 @"$e4main4boolSbyF"()
 // CHECK: define {{.*}}{{i32|i64}} @"$e4main3intSiyF"()
 // CHECK: define {{.*}}ptr @"$e4main3ptr1p1nS2V_SitF"(ptr %0, {{i32|i64}} %1)
diff --git a/test/embedded/stdlib-dictionary.swift b/test/embedded/stdlib-dictionary.swift
index 53b37e7218ee7..ac4dbfbc67214 100644
--- a/test/embedded/stdlib-dictionary.swift
+++ b/test/embedded/stdlib-dictionary.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: embedded_stdlib_cross_compiling
@@ -20,4 +21,4 @@ public func test() {
 
 test()
 
-// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}(i32 %0, ptr %1)
diff --git a/test/embedded/stdlib-random.swift b/test/embedded/stdlib-random.swift
index c9472fe305d22..4e3eaa4d8a6c9 100644
--- a/test/embedded/stdlib-random.swift
+++ b/test/embedded/stdlib-random.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: embedded_stdlib_cross_compiling
@@ -19,4 +20,4 @@ public func test() {
 
 test()
 
-// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}(i32 %0, ptr %1)
diff --git a/test/embedded/stdlib-set.swift b/test/embedded/stdlib-set.swift
index e81506d843012..bf7e0cad3a204 100644
--- a/test/embedded/stdlib-set.swift
+++ b/test/embedded/stdlib-set.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: CODEGENERATOR=ARM
@@ -28,4 +29,4 @@ public func test() {
 
 test()
 
-// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}(i32 %0, ptr %1)
diff --git a/test/embedded/stdlib-strings-interpolation3.swift b/test/embedded/stdlib-strings-interpolation3.swift
index 7631046caed3e..f98ffc34ed36b 100644
--- a/test/embedded/stdlib-strings-interpolation3.swift
+++ b/test/embedded/stdlib-strings-interpolation3.swift
@@ -2,6 +2,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -emit-ir %s -enable-experimental-feature Embedded -O
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -emit-ir %s -enable-experimental-feature Embedded -Osize
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: CODEGENERATOR=ARM
 // REQUIRES: embedded_stdlib_cross_compiling
diff --git a/test/embedded/stdlib-strings-lossless-convertible.swift b/test/embedded/stdlib-strings-lossless-convertible.swift
new file mode 100644
index 0000000000000..e851e3a80d68e
--- /dev/null
+++ b/test/embedded/stdlib-strings-lossless-convertible.swift
@@ -0,0 +1,32 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo %embedded-unicode-tables) | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: optimized_stdlib
+// REQUIRES: OS=macosx || OS=linux-gnu
+// REQUIRES: swift_feature_Embedded
+
+func f<T: LosslessStringConvertible>(t: inout T?, s: String) {
+  t = .init(s)
+}
+
+@main
+struct Main {
+  static func main() {
+    if let b = Bool.init("true"), b == true { print("OK 1") } // CHECK: OK 1
+    var b: Bool?
+    f(t: &b, s: "false")
+    if let b, b == false { print("OK 2") } // CHECK: OK 2
+
+    if let i = Int.init("17"), i == 17 { print("OK 3") } // CHECK: OK 3
+    var i: Int?
+    f(t: &i, s: "777")
+    if let i, i == 777 { print("OK 4") } // CHECK: OK 4
+
+    // TODO: Add float parsing to Embedded Swift that does not rely on libc
+    // if let fl = Float.init("42.42"), fl == 42.42 { print("OK 5") } // XXX: OK 5
+    // var fl: Float?
+    // f(t: &fl, s: "12.34")
+    // if let fl, fl == 12.34 { print("OK 6") } // XXX: OK 6
+  }
+}
diff --git a/test/embedded/stdlib-types-riscv.swift b/test/embedded/stdlib-types-riscv.swift
index 0d4bdacf06943..820bbfe269616 100644
--- a/test/embedded/stdlib-types-riscv.swift
+++ b/test/embedded/stdlib-types-riscv.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target riscv32-none-none-eabi -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target riscv64-none-none-eabi -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: CODEGENERATOR=RISCV
diff --git a/test/embedded/stdlib-types.swift b/test/embedded/stdlib-types.swift
index cbd2b65e2d947..c3f57104122b9 100644
--- a/test/embedded/stdlib-types.swift
+++ b/test/embedded/stdlib-types.swift
@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
+// UNSUPPORTED: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
 // REQUIRES: CODEGENERATOR=ARM
@@ -47,4 +48,4 @@ public func test() {
 
 test()
 
-// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK: define {{.*}}i32 @{{_*}}main{{.*}}(i32 %0, ptr %1)
diff --git a/test/embedded/synchronization.swift b/test/embedded/synchronization.swift
index 751353928b236..d2a2fb7ffbd93 100644
--- a/test/embedded/synchronization.swift
+++ b/test/embedded/synchronization.swift
@@ -1,7 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend %s -parse-as-library -enable-experimental-feature Embedded -disable-availability-checking -c -o %t/main.o
-// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
-// RUN: %target-run %t/a.out | %FileCheck %s
+// RUN: %target-run-simple-swift(-parse-as-library -enable-experimental-feature Embedded -disable-availability-checking -wmo) | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: executable_test
diff --git a/test/embedded/traps-fatalerror-ir.swift b/test/embedded/traps-fatalerror-ir.swift
index 3c4778d5265aa..d2f31fbb30401 100644
--- a/test/embedded/traps-fatalerror-ir.swift
+++ b/test/embedded/traps-fatalerror-ir.swift
@@ -4,8 +4,10 @@
 // RUN: %target-swift-emit-ir -enable-experimental-feature Embedded -wmo %s -O     -assert-config Debug | %FileCheck %s --check-prefix=CHECK-MESSAGE
 // RUN: %target-swift-emit-ir -enable-experimental-feature Embedded -wmo %s -Osize -assert-config Debug | %FileCheck %s --check-prefix=CHECK-MESSAGE
 
+// XFAIL: CPU=wasm32
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
+// REQUIRES: swift_stdlib_no_asserts
 // REQUIRES: swift_feature_Embedded
 
 public func test() {
diff --git a/test/embedded/typeof.swift b/test/embedded/typeof.swift
index c364ba964d3cd..5905380810301 100644
--- a/test/embedded/typeof.swift
+++ b/test/embedded/typeof.swift
@@ -20,5 +20,5 @@ public func test() {
   var args: (Int, Int, Int, Int) = (0, 0, 0, 0)
   let n = 2
   let value = 42
-  unsafeWriteArray(type(of: args.0), array: &args, index: n, value: value) // expected-note {{called from here}}
+  unsafeWriteArray(type(of: args.0), array: &args, index: n, value: value) // expected-note {{generic specialization called here}}
 }
diff --git a/test/embedded/unowned-task-executor.swift b/test/embedded/unowned-task-executor.swift
new file mode 100644
index 0000000000000..e02ae1f525279
--- /dev/null
+++ b/test/embedded/unowned-task-executor.swift
@@ -0,0 +1,33 @@
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -disable-availability-checking -module-name test -parse-as-library %s -emit-ir | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: swift_in_compiler
+// REQUIRES: optimized_stdlib
+// REQUIRES: OS=macosx
+// REQUIRES: swift_feature_Embedded
+
+// check lines do not match ptrauch code
+// UNSUPPORTED: CPU=arm64e
+
+import _Concurrency
+
+public var e: (any TaskExecutor)? = nil
+
+// CHECK-LABEL: define {{.*}}@"$e4test6testits19UnownedTaskExecutorVyF"()
+// CHECK: [[EXISTENTIAL_ADDR:%.*]] = call {{.*}}"$e4test1eSch_pSgvau"
+// CHECK: [[INSTANCE_ADDR:%.*]] = getelementptr {{.*}}[[EXISTENTIAL_ADDR]]{{, i[0-9]+ 0, i[0-9]+ 0}}
+// CHECK: [[INSTANCE:%.*]] = load {{.*}}ptr [[INSTANCE_ADDR]]
+// CHECK: [[CONFORMANCE_ADDR:%.*]] = getelementptr {{.*}}[[EXISTENTIAL_ADDR]]{{, i[0-9]+ 0, i[0-9]+ 1}}
+// CHECK: [[CONFORMANCE:%.*]] = load {{.*}}ptr [[CONFORMANCE_ADDR]]
+// CHECK: {{^[0-9a-z]+:}}
+// CHECK: [[INSTANCE_PTR:%.*]] = inttoptr {{i[0-9]+}} [[INSTANCE]]
+// CHECK: [[CONFORMANCE_PTR:%.*]] = inttoptr {{i[0-9]+}} [[CONFORMANCE]]
+// CHECK: [[INSTANCE_PHI:%.*]] = phi ptr [ [[INSTANCE_PTR]]
+// CHECK: [[CONFORMANCE_PHI:%.*]] = phi ptr [ [[CONFORMANCE_PTR]]
+// CHECK: [[INSTANCE_ISA:%.*]] = load ptr, ptr [[INSTANCE_PHI]]
+// CHECK: call {{.*}}@"$es19UnownedTaskExecutorVyABxhcSchRzlufC"(ptr [[INSTANCE_PHI]], ptr [[INSTANCE_ISA]], ptr [[CONFORMANCE_PHI]])
+// CHECK-LABEL: {{^}}}
+public func testit() -> UnownedTaskExecutor {
+  return unsafe UnownedTaskExecutor(e!)
+}
+
diff --git a/test/embedded/value-type-deinits.swift b/test/embedded/value-type-deinits.swift
index 2b049cce084c4..8408a8be592a8 100644
--- a/test/embedded/value-type-deinits.swift
+++ b/test/embedded/value-type-deinits.swift
@@ -31,6 +31,6 @@ public func test() {
   createFoo(x: 1)
 }
 
-// CHECK-LABEL: sil @$e8MyModule9createFoo1xyx_ts17FixedWidthIntegerRzlFSi_Ttg5 :
+// CHECK-LABEL: sil shared @$e8MyModule9createFoo1xyx_ts17FixedWidthIntegerRzlFSi_Ttg5 :
 // CHECK-NOT:     release
 // CHECK:       } // end sil function '$e8MyModule9createFoo1xyx_ts17FixedWidthIntegerRzlFSi_Ttg5'
diff --git a/test/embedded/wasm/wasilibc_functions.swift b/test/embedded/wasm/wasilibc_functions.swift
new file mode 100644
index 0000000000000..0fe9cfafc1424
--- /dev/null
+++ b/test/embedded/wasm/wasilibc_functions.swift
@@ -0,0 +1,18 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -parse-as-library -wmo) | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: OS=wasip1
+// REQUIRES: swift_feature_Embedded
+
+import WASILibc
+@main struct Main {
+  static func main() {
+    puts("Hello")
+    // CHECK: Hello
+    let div_result = div(5,2)
+    print(div_result.quot)
+    // CHECK: 2
+    print(div_result.rem)
+    // CHECK: 1
+  }
+}
diff --git a/test/embedded/weak-unowned.swift b/test/embedded/weak-unowned.swift
index 9700b1df6cff1..7ac40301cf07d 100644
--- a/test/embedded/weak-unowned.swift
+++ b/test/embedded/weak-unowned.swift
@@ -10,7 +10,7 @@ public class MyClass { }
 
 public struct MyStruct {
   var normalVar: MyClass
-  weak var weakVar: MyClass? // expected-error {{attribute 'weak' cannot be used in embedded Swift}}
-  unowned var unownedVar: MyClass // expected-error {{attribute 'unowned' cannot be used in embedded Swift}}
+  weak var weakVar: MyClass? // expected-error {{attribute 'weak' cannot be used in Embedded Swift}}
+  unowned var unownedVar: MyClass // expected-error {{attribute 'unowned' cannot be used in Embedded Swift}}
   unowned(unsafe) var unownedUnsafe: MyClass
 }
diff --git a/test/embedded/without-actually-escaping.swift b/test/embedded/without-actually-escaping.swift
index 48e1cd9adc6b5..301a0a66b4ceb 100644
--- a/test/embedded/without-actually-escaping.swift
+++ b/test/embedded/without-actually-escaping.swift
@@ -2,7 +2,7 @@
 // RUN: %target-clang -x c -c %S/Inputs/unbuffered-putchar.c -o %t/unbuffered-putchar.o
 
 // RUN: %target-build-swift -enable-experimental-feature Embedded -wmo %s -Xlinker %t/unbuffered-putchar.o -o %t/a.out
-// RUN: not --crash %t/a.out 2>&1 | %FileCheck %s
+// RUN: %target-not-crash %target-run %t/a.out 2>&1 | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: executable_test
diff --git a/test/expr/capture/top-level-guard.swift b/test/expr/capture/top-level-guard.swift
index 154c5804dad97..c0b2d8f4d492d 100644
--- a/test/expr/capture/top-level-guard.swift
+++ b/test/expr/capture/top-level-guard.swift
@@ -39,7 +39,7 @@ let closureCapture: () -> Void = { [x] in
 }
 
 // CHECK-LABEL: (defer_stmt
-// CHECK-NEXT: (func_decl{{.*}}implicit "$defer()" interface_type="() -> ()" access=fileprivate captures=(x<direct><noescape>)
+// CHECK-NEXT: (func_decl{{.*}}implicit range={{.*}} "$defer()" interface_type="() -> ()" access=fileprivate captures=(x<direct><noescape>)
 defer {
   _ = x
 }
diff --git a/test/expr/cast/optional.swift b/test/expr/cast/optional.swift
index 9bd5063e7b0c3..825f3481d1b53 100644
--- a/test/expr/cast/optional.swift
+++ b/test/expr/cast/optional.swift
@@ -45,5 +45,6 @@ func implicitCastOfLiteralToOptional() {
 // https://github.com/apple/swift/issues/46093
 func castUnrelatedOptionalTypes(x: Int?) {
   let _ = x as String? // expected-error {{cannot convert value}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('Int' and 'String') are expected to be equal}}
   let _ = x as? String? // no-warning
 }
diff --git a/test/expr/closure/closures.swift b/test/expr/closure/closures.swift
index 8d131c1456260..8e13cfd346726 100644
--- a/test/expr/closure/closures.swift
+++ b/test/expr/closure/closures.swift
@@ -1,4 +1,7 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking
+// RUN: %target-typecheck-verify-swift -disable-availability-checking -verify-additional-prefix no-weak-let-
+// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-upcoming-feature ImmutableWeakCaptures -verify-additional-prefix has-weak-let-
+
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 var func6 : (_ fn : (Int,Int) -> Int) -> ()
 var func6a : ((Int, Int) -> Int) -> ()
@@ -262,12 +265,29 @@ class ExplicitSelfRequiredTest {
   // because its `sawError` flag is set to true. To preserve the "capture 'y' was never used" warnings
   // above, we put these cases in their own method.
   func weakSelfError() {
-    doVoidStuff({ [weak self] in x += 1 }) // expected-error {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-warning {{variable 'self' was written to, but never read}}
-    doVoidStuffNonEscaping({ [weak self] in x += 1 }) // expected-warning {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-warning {{variable 'self' was written to, but never read}}
-    doStuff({ [weak self] in x+1 }) // expected-error {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-warning {{variable 'self' was written to, but never read}}
-    doVoidStuff({ [weak self] in _ = method() }) // expected-error {{call to method 'method' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-warning {{variable 'self' was written to, but never read}}
-    doVoidStuffNonEscaping({ [weak self] in _ = method() }) // expected-warning {{call to method 'method' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-warning {{variable 'self' was written to, but never read}}
-    doStuff({ [weak self] in method() }) // expected-error {{call to method 'method' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-warning {{variable 'self' was written to, but never read}}
+    doVoidStuff({ [weak self] in x += 1 }) // expected-error {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}}
+    // expected-no-weak-let-warning@-1 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@-2 {{capture 'self' was never used}}
+
+    doVoidStuffNonEscaping({ [weak self] in x += 1 }) // expected-warning {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}}
+    // expected-no-weak-let-warning@-1 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@-2 {{capture 'self' was never used}}
+
+    doStuff({ [weak self] in x+1 }) // expected-error {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}}
+    // expected-no-weak-let-warning@-1 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@-2 {{capture 'self' was never used}}
+
+    doVoidStuff({ [weak self] in _ = method() }) // expected-error {{call to method 'method' in closure requires explicit use of 'self' to make capture semantics explicit}}
+    // expected-no-weak-let-warning@-1 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@-2 {{capture 'self' was never used}}
+
+    doVoidStuffNonEscaping({ [weak self] in _ = method() }) // expected-warning {{call to method 'method' in closure requires explicit use of 'self' to make capture semantics explicit}}
+    // expected-no-weak-let-warning@-1 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@-2 {{capture 'self' was never used}}
+
+    doStuff({ [weak self] in method() }) // expected-error {{call to method 'method' in closure requires explicit use of 'self' to make capture semantics explicit}}
+    // expected-no-weak-let-warning@-1 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@-2 {{capture 'self' was never used}}
   }
 }
 
@@ -374,7 +394,8 @@ extension SomeClass {
     //expected-error@-3{{reference to property 'in' in closure requires explicit use of 'self' to make capture semantics explicit}}
     //expected-note@-4{{reference 'self.' explicitly}}
 
-    // expected-warning @+1 {{variable 'self' was written to, but never read}}
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
     doStuff { [weak self&field] in 42 }  // expected-error {{expected ']' at end of capture list}}
 
   }
@@ -511,6 +532,7 @@ func lvalueCapture<T>(c: GenericClass<T>) {
     _ = wc
 
     cc = wc!
+    wc = cc
   }
 }
 
@@ -1521,22 +1543,30 @@ final class AutoclosureTests {
         withEscapingAutoclosure(bar()) // expected-warning {{call to method 'bar' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note {{reference 'self.' explicitly}}
       }
     }
-    
-    doVoidStuff { [weak self] in // expected-warning {{variable 'self' was written to, but never read}}
+
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
+    doVoidStuff { [weak self] in
       withNonEscapingAutoclosure(bar()) // expected-error {{call to method 'bar' in closure requires explicit use of 'self' to make capture semantics explicit}}
     }
-    
-    doVoidStuff { [weak self] in // expected-warning {{variable 'self' was written to, but never read}}
+
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
+    doVoidStuff { [weak self] in
       withEscapingAutoclosure(bar()) // expected-error {{call to method 'bar' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note {{reference 'self.' explicitly}}
     }
-    
-    doVoidStuff { [weak self] in // expected-warning {{variable 'self' was written to, but never read}}
+
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
+    doVoidStuff { [weak self] in
       doVoidStuff { // expected-note {{capture 'self' explicitly to enable implicit 'self' in this closure}}
         withNonEscapingAutoclosure(bar()) // expected-error {{all to method 'bar' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note {{reference 'self.' explicitly}}
       }
     }
-      
-    doVoidStuff { [weak self] in // expected-warning {{variable 'self' was written to, but never read}}
+
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
+    doVoidStuff { [weak self] in
       doVoidStuff {
         withEscapingAutoclosure(bar()) // expected-error {{call to method 'bar' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note {{reference 'self.' explicitly}}
       }
@@ -1603,9 +1633,13 @@ final class AutoclosureTests {
       let someOptional: Self? = Self()
       var `self` = self ?? someOptional // expected-warning {{'self' was never mutated; consider changing to 'let' constant}}
       guard let self = self else { return }
+#if hasFeature(ImmutableWeakCaptures)
+      method() // expected-has-weak-let-error{{call to method 'method' in closure requires explicit use of 'self' to make capture semantics explicit}}
+#else
       // This is not supposed to be permitted, but has been allowed since Swift 5.8,
       // so we have to continue allowing it to maintain source compatibility.
       method()
+#endif
     }
   
     doVoidStuff { // expected-note {{capture 'self' explicitly to enable implicit 'self' in this closure}}
@@ -1771,13 +1805,17 @@ class rdar129475277 {
   func method() {}
 
   func test1() {
-    takesEscapingWithAllowedImplicitSelf { [weak self] in // expected-warning {{variable 'self' was written to, but never read}}
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
+    takesEscapingWithAllowedImplicitSelf { [weak self] in
       takesEscapingWithAllowedImplicitSelf {
         method() // expected-warning {{call to method 'method' in closure requires explicit use of 'self' to make capture semantics explicit}}
       }
     }
 
-    takesEscapingWithAllowedImplicitSelf { [weak self] in // expected-warning {{variable 'self' was written to, but never read}}
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
+    takesEscapingWithAllowedImplicitSelf { [weak self] in
       takesEscapingWithAllowedImplicitSelf {
         doVoidStuffNonEscaping {
           withNonEscapingAutoclosure(bar()) // expected-warning {{call to method 'bar' in closure requires explicit use of 'self' to make capture semantics explicit}}
@@ -1785,7 +1823,9 @@ class rdar129475277 {
       }
     }
 
-    takesEscapingWithAllowedImplicitSelf { [weak self] in // expected-warning {{variable 'self' was written to, but never read}}
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
+    takesEscapingWithAllowedImplicitSelf { [weak self] in
       withNonEscapingAutoclosure(bar()) // expected-warning {{call to method 'bar' in closure requires explicit use of 'self' to make capture semantics explicit}}
     }
   }
@@ -1818,7 +1858,9 @@ class TestExtensionOnOptionalSelf {
 
 extension TestExtensionOnOptionalSelf? {
   func foo() {
-    _ = { [weak self] in // expected-warning {{variable 'self' was written to, but never read}}
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
+    _ = { [weak self] in
       foo() // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}}
     }
 
@@ -1826,7 +1868,9 @@ extension TestExtensionOnOptionalSelf? {
       foo()
     }
 
-    _ = { [weak self] in // expected-warning {{variable 'self' was written to, but never read}}
+    // expected-no-weak-let-warning@+2 {{variable 'self' was written to, but never read}}
+    // expected-has-weak-let-warning@+1 {{capture 'self' was never used}}
+    _ = { [weak self] in
       _ = {
         foo()
       }
diff --git a/test/expr/closure/closures_swift6.swift b/test/expr/closure/closures_swift6.swift
index 5a44c7b813191..18859b75848f1 100644
--- a/test/expr/closure/closures_swift6.swift
+++ b/test/expr/closure/closures_swift6.swift
@@ -1,4 +1,12 @@
-// RUN: %target-typecheck-verify-swift -swift-version 6
+// There seems to be a minor bug in the diagnostic of the self-capture.
+// Diagnostic algorithm does not @lvalue DeclRefExpr wrapped into LoadExpr,
+// and enabling ImmutableWeakCaptures removes the LoadExpr.
+// As a result, diagnostic messages change slightly.
+
+// RUN: %target-typecheck-verify-swift -swift-version 6 -verify-additional-prefix no-weak-let-
+// RUN: %target-typecheck-verify-swift -swift-version 6 -verify-additional-prefix has-weak-let- -enable-upcoming-feature ImmutableWeakCaptures
+
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 func doStuff(_ fn : @escaping () -> Int) {}
 func doVoidStuff(_ fn : @escaping () -> ()) {}
@@ -936,7 +944,9 @@ class TestExtensionOnOptionalSelf {
 extension TestExtensionOnOptionalSelf? {
   func foo() {
     _ = { [weak self] in
-      foo() // expected-error {{implicit use of 'self' in closure; use 'self.' to make capture semantics explicit}}
+      // expected-no-weak-let-error@+2 {{implicit use of 'self' in closure; use 'self.' to make capture semantics explicit}}
+      // expected-has-weak-let-error@+1 {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}}
+      foo()
     }
 
     _ = {
@@ -946,8 +956,11 @@ extension TestExtensionOnOptionalSelf? {
     }
 
     _ = { [weak self] in
-      _ = {
-        foo() // expected-error {{implicit use of 'self' in closure; use 'self.' to make capture semantics explicit}}
+      _ = { // expected-has-weak-let-note {{capture 'self' explicitly to enable implicit 'self' in this closure}}
+        // expected-no-weak-let-error@+3 {{implicit use of 'self' in closure; use 'self.' to make capture semantics explicit}}
+        // expected-has-weak-let-error@+2 {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}}
+        // expected-has-weak-let-note@+1 {{reference 'self.' explicitly}}
+        foo()
         self.foo()
         self?.bar()
       }
@@ -967,7 +980,9 @@ extension TestExtensionOnOptionalSelf? {
 extension TestExtensionOnOptionalSelf {
   func foo() {
     _ = { [weak self] in
-      foo() // expected-error {{implicit use of 'self' in closure; use 'self.' to make capture semantics explicit}}
+      // expected-no-weak-let-error@+2 {{implicit use of 'self' in closure; use 'self.' to make capture semantics explicit}}
+      // expected-has-weak-let-error@+1 {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}}
+      foo()
       self.foo()
       self?.bar()
     }
@@ -978,8 +993,11 @@ extension TestExtensionOnOptionalSelf {
     }
 
     _ = { [weak self] in
-      _ = {
-        foo() // expected-error {{implicit use of 'self' in closure; use 'self.' to make capture semantics explicit}}
+      _ = { // expected-has-weak-let-note {{capture 'self' explicitly to enable implicit 'self' in this closure}}
+        // expected-no-weak-let-error@+3 {{implicit use of 'self' in closure; use 'self.' to make capture semantics explicit}}
+        // expected-has-weak-let-error@+2 {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}}
+        // expected-has-weak-let-note@+1 {{reference 'self.' explicitly}}
+        foo()
         self.foo()
       }
     }
diff --git a/test/expr/closure/implicit_weak_capture.swift b/test/expr/closure/implicit_weak_capture.swift
index 96b7688a1f20e..870d90505e013 100644
--- a/test/expr/closure/implicit_weak_capture.swift
+++ b/test/expr/closure/implicit_weak_capture.swift
@@ -1,7 +1,9 @@
 // RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -swift-version 6)
+// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -swift-version 6 -enable-upcoming-feature ImmutableWeakCaptures)
 
 // REQUIRES: concurrency
 // REQUIRES: executable_test
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 // rdar://102155748
 // UNSUPPORTED: back_deployment_runtime
@@ -13,37 +15,50 @@ func runIn10ms(_ closure: @escaping @Sendable () -> Void) {
   }
 }
 
+let checkInterval = 10_000_000
+let checkIters = 1000
+
 final class Weak: Sendable {
   let property = "Self exists"
 
-  func test() {
-    runIn10ms { [weak self] in
-      if let self {
-        // Use implicit self -- this should not result in a strong capture
-        _ = property
-        fatalError("Self was unexpectedly captured strongly")
-      } else {
-        print("Self was captured weakly (1)")
+  func test() async -> (Task<Void, Never>, Task<Void, Never>) {
+    let t1 = Task { [weak self] in
+      for _ in 0..<checkIters {
+        if let self {
+          // Use implicit self -- this should not result in a strong capture
+          _ = property
+        } else {
+          print("Self was captured weakly (1)")
+          return
+        }
+        try! await Task.sleep(nanoseconds: 10_000_000)
       }
+      fatalError("Self was unexpectedly captured strongly")
     }
 
-    runIn10ms { [weak self] in
-      guard let self else {
-        print("Self was captured weakly (2)")
-        return
-      }
+    let t2 = Task { [weak self] in
+      for _ in 0..<checkIters {
+        guard let self else {
+          print("Self was captured weakly (2)")
+          return
+        }
 
-      // Use implicit self -- this should not result in a strong capture
-      _ = property
-
-      runIn10ms { [self] in
         // Use implicit self -- this should not result in a strong capture
         _ = property
-        fatalError("Self was unexpectedly captured strongly")
+
+        runIn10ms { [self] in
+          // Use implicit self -- this should not result in a strong capture
+          _ = property
+        }
+        try! await Task.sleep(nanoseconds: 10_000_000)
       }
+      fatalError("Self was unexpectedly captured strongly")
     }
+
+    return (t1, t2)
   }
 }
 
-Weak().test()
-try await Task.sleep(nanoseconds: 30_000_000)
+let (t1, t2) = await Weak().test()
+await t1.value
+await t2.value
diff --git a/test/expr/closure/trailing.swift b/test/expr/closure/trailing.swift
index 58b43d5ee4239..4f8591acd2c2c 100644
--- a/test/expr/closure/trailing.swift
+++ b/test/expr/closure/trailing.swift
@@ -488,3 +488,39 @@ func rdar92521618() {
   if let _ = { foo {} }() {}
   guard let _ = { foo {} }() else { return }
 }
+
+// Argument matching never binds trailing closure arguments to
+// defaulted/variadic parameters of non-function type.
+do {
+  // Trailing closure not considered fulfilled by 'arg'.
+  // Note: Used to crash.
+  do {
+    func variadic(arg: Int...) {} // expected-note@:10 {{'variadic(arg:)' declared here}}{{none}}
+    func defaulted(arg: Int = 0) {}
+
+    let _ = variadic { return () }
+    // expected-error@-1:22 {{trailing closure passed to parameter of type 'Int' that does not accept a closure}}{{none}}
+    let _ = defaulted { return () }
+    // expected-error@-1:23 {{extra trailing closure passed in call}}{{none}}
+  }
+  // Trailing closure considered fulfilled by 'x' instead of 'arg'.
+  do {
+    func variadic(arg: Int..., x: String) {} // expected-note@:10 {{'variadic(arg:x:)' declared here}}{{none}}
+    func defaulted(arg: Int = 0, x: String) {} // expected-note@:10 {{'defaulted(arg:x:)' declared here}}{{none}}
+
+    let _ = variadic { return () }
+    // expected-error@-1:22 {{trailing closure passed to parameter of type 'String' that does not accept a closure}}{{none}}
+    let _ = defaulted { return () }
+    // expected-error@-1:23 {{trailing closure passed to parameter of type 'String' that does not accept a closure}}{{none}}
+  }
+  // Trailing closure considered fulfilled by 'arg'; has function type.
+  do {
+    func variadic(arg: ((Int) -> Void)...) {}
+    func defaulted(arg: ((Int) -> Void) = { _ in }) {}
+
+    let _ = variadic { return () }
+    // expected-error@-1:22 {{contextual type for closure argument list expects 1 argument, which cannot be implicitly ignored}}{{23-23= _ in}}
+    let _ = defaulted { return () }
+    // expected-error@-1:23 {{contextual type for closure argument list expects 1 argument, which cannot be implicitly ignored}}{{24-24= _ in}}
+  }
+}
diff --git a/test/expr/closure/typed_throws.swift b/test/expr/closure/typed_throws.swift
index 26500dd2b2bb8..29b0e8d0b8875 100644
--- a/test/expr/closure/typed_throws.swift
+++ b/test/expr/closure/typed_throws.swift
@@ -8,6 +8,8 @@ enum MyBadError {
   case fail
 }
 
+struct GenericError<T>: Error {}
+
 func testClosures() {
   let c1 = { () throws(MyError) in
     throw .fail
@@ -36,5 +38,8 @@ func testClosures() {
   let c2 = { throw MyError.fail }
   let _: Int = c2
   // expected-error@-1{{cannot convert value of type '() throws -> ()'}}
+
+  _ = { () throws(_) in } // expected-error {{type placeholder not allowed here}}
+  _ = { () throws(GenericError<_>) in } // expected-error {{type placeholder not allowed here}}
 }
 
diff --git a/test/expr/conversions/RawRepresentable_fixits.swift b/test/expr/conversions/RawRepresentable_fixits.swift
new file mode 100644
index 0000000000000..5298666f9b510
--- /dev/null
+++ b/test/expr/conversions/RawRepresentable_fixits.swift
@@ -0,0 +1,230 @@
+// RUN: %target-typecheck-verify-swift
+
+do {
+  struct Mask : OptionSet {
+    init(_ rawValue: UInt) {}
+    init(rawValue: UInt) {}
+
+    var rawValue: UInt { 0 }
+
+    static var Bingo: Mask { Mask(1) }
+  }
+
+  // FIXME: No fix-it. Could be '= Mask(rawValue: 0)' or '= []'.
+  let _: Mask = 0
+  // expected-error@-1:17 {{cannot convert value of type 'Int' to specified type 'Mask'}}{{none}}
+}
+
+do {
+  enum E: Int {
+    case a
+  }
+
+  // TODO: A better fix-it is to remove the init call.
+  _ = E(E.a)
+  // expected-error@-1:9 {{missing argument label 'rawValue:' in call}}{{9-9=rawValue: }}
+  // expected-error@-2:11 {{cannot convert value of type 'E' to expected argument type 'Int'}}{{12-12=.rawValue}}
+}
+
+// Fix-its for expectation of implicit RawRepresentable <-> RawValue cast.
+do {
+  struct Mask : OptionSet {
+    init(rawValue: UInt64) {}
+    var rawValue: UInt64 { return 0 }
+  }
+
+  // RawValue -> RawRepresentable / OptionSet.
+  do {
+    struct Mask : OptionSet {
+      init(rawValue: UInt64) {}
+      var rawValue: UInt64 { return 0 }
+    }
+
+    func takeMask(_: Mask) {}
+    func takeMask_o(_: Mask?) {}
+
+    let int: Int
+    let int_o: Int?
+    let uint64: UInt64
+    let uint64_o: UInt64?
+
+    // FIXME: No fix-it. Could be 'Mask(rawValue: 1)'.
+    let _: Mask = 1
+    // expected-error@-1:19 {{cannot convert value of type 'Int' to specified type 'Mask'}}{{none}}
+    takeMask(1)
+    // expected-error@-1:14 {{cannot convert value of type 'Int' to expected argument type 'Mask'}}{{none}}
+
+    // FIXME: No fix-it. Could be 'Mask(rawValue: UInt64(int))'.
+    let _: Mask = int
+    // expected-error@-1:19 {{cannot convert value of type 'Int' to specified type 'Mask'}}{{none}}
+    takeMask(int)
+    // expected-error@-1:14 {{cannot convert value of type 'Int' to expected argument type 'Mask'}}{{none}}
+
+    let _: Mask = uint64
+    // expected-error@-1:19 {{cannot convert value of type 'UInt64' to specified type 'Mask'}}{{19-19=Mask(rawValue: }}{{25-25=) ?? <#default value#>}}
+    takeMask(uint64)
+    // expected-error@-1:14 {{cannot convert value of type 'UInt64' to expected argument type 'Mask'}}{{14-14=Mask(rawValue: }}{{20-20=) ?? <#default value#>}}
+
+    // FIXME: No fix-it. Could be 'Mask(rawValue: UInt64(int_o ?? <#default value#>)'.
+    let _: Mask = int_o
+    // expected-error@-1:19 {{cannot convert value of type 'Int?' to specified type 'Mask'}}{{none}}
+    takeMask(int_o)
+    // expected-error@-1:14 {{cannot convert value of type 'Int?' to expected argument type 'Mask'}}{{none}}
+
+    // FIXME: No fix-it. Could be 'Mask(rawValue: 1)'.
+    let _: Mask? = 1
+    // expected-error@-1:20 {{cannot convert value of type 'Int' to specified type 'Mask'}}{{none}}
+    takeMask_o(1)
+    // expected-error@-1:16 {{cannot convert value of type 'Int' to expected argument type 'Mask'}}{{none}}
+
+    // FIXME: No fix-it. Could be 'Mask(rawValue: UInt64(int))'.
+    let _: Mask? = int
+    // expected-error@-1:20 {{cannot convert value of type 'Int' to specified type 'Mask'}}{{none}}
+    takeMask_o(int)
+    // expected-error@-1:16 {{cannot convert value of type 'Int' to expected argument type 'Mask'}}{{none}}
+
+    // FIXME: No fix-it. Could be 'int_o.map { Mask(rawValue: UInt64($0)) }'.
+    let _: Mask? = int_o
+    // expected-error@-1:20 {{cannot assign value of type 'Int?' to type 'Mask?'}}{{none}}
+    // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Int' and 'Mask') are expected to be equal}}
+    takeMask_o(int_o)
+    // expected-error@-1:16 {{cannot convert value of type 'Int?' to expected argument type 'Mask?'}}{{none}}
+    // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Int' and 'Mask') are expected to be equal}}
+
+    // FIXME: No fix-it. Could be 'uint64_o.map(Mask(rawValue:))' or 'uint64_o.map { Mask(rawValue: $0) }'.
+    let _: Mask? = uint64_o
+    // expected-error@-1:20 {{cannot assign value of type 'UInt64?' to type 'Mask?'}}{{none}}
+    // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('UInt64' and 'Mask') are expected to be equal}}
+    takeMask_o(uint64_o)
+    // expected-error@-1:16 {{cannot convert value of type 'UInt64?' to expected argument type 'Mask?'}}{{none}}
+    // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('UInt64' and 'Mask') are expected to be equal}}
+
+    // FIXME: No fix-it. Could be '(anything as? Int).map { Mask(rawValue: UInt64($0)) }'.
+    let anything: Any
+    let _: Mask? = anything as? Int
+    // expected-error@-1:29 {{cannot assign value of type 'Int?' to type 'Mask?'}}{{none}}
+    // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Int' and 'Mask') are expected to be equal}}
+    takeMask_o(anything as? Int)
+    // expected-error@-1:25 {{cannot convert value of type 'Int?' to expected argument type 'Mask?'}}{{none}}
+    // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Int' and 'Mask') are expected to be equal}}
+  }
+
+  // Try a nested OptionSet.
+  do {
+    struct Shell {
+      struct Mask : OptionSet {
+        init(rawValue: UInt64) {}
+        var rawValue: UInt64 { return 0 }
+      }
+    }
+
+    // FIXME: This is an OptionSet, coelescing in the fix-it is not necessary.
+    let _: Shell.Mask = UInt64(0)
+    // expected-error@-1:25 {{cannot convert value of type 'UInt64' to specified type 'Shell.Mask'}}{{25-25=Shell.Mask(rawValue: }}{{34-34=) ?? <#default value#>}}
+  }
+
+  // Try a non-integral RawValue.
+  do {
+    struct Mask : RawRepresentable {
+      init(rawValue: String) {}
+      var rawValue: String { return "" }
+    }
+
+    let s: String
+    let _: Mask = "\(s)}"
+    // expected-error@-1:19 {{cannot convert value of type 'String' to specified type 'Mask'}}{{19-19=Mask(rawValue: }}{{26-26=) ?? <#default value#>}}
+  }
+
+  // RawRepresentable / OptionSet -> RawValue.
+  do {
+    struct Mask : OptionSet {
+      init(rawValue: UInt64) {}
+      var rawValue: UInt64 { return 0 }
+    }
+
+    func takeInt(_: Int) {}
+    func takeInt_o(_: Int?) {}
+    func takeUInt64(_: UInt64) {}
+    func takeUInt64_o(_: UInt64?) {}
+
+    let mask: Mask
+    let mask_o: Mask?
+
+    // FIXME: No fix-it. Could be 'Int(mask.rawValue)'.
+    let _: Int = mask
+    // expected-error@-1:18 {{cannot convert value of type 'Mask' to specified type 'Int'}}{{none}}
+    takeInt(mask)
+    // expected-error@-1:13 {{cannot convert value of type 'Mask' to expected argument type 'Int'}}{{none}}
+
+    let _: UInt64 = mask
+    // expected-error@-1:21 {{cannot convert value of type 'Mask' to specified type 'UInt64'}}{{25-25=.rawValue}}
+    takeUInt64(mask)
+    // expected-error@-1:16 {{cannot convert value of type 'Mask' to expected argument type 'UInt64'}}{{20-20=.rawValue}}
+
+    let _: UInt64 = mask_o
+    // expected-error@-1:21 {{cannot convert value of type 'Mask?' to specified type 'UInt64'}}{{27-27=?.rawValue ?? <#default value#>}}
+    takeUInt64(mask_o)
+    // expected-error@-1:16 {{cannot convert value of type 'Mask?' to expected argument type 'UInt64'}}{{22-22=?.rawValue ?? <#default value#>}}
+
+    // FIXME: No fix-it. Could be 'mask_o.map { Int($0.rawValue) }'.
+    let _: Int? = mask_o
+    // expected-error@-1:19 {{cannot assign value of type 'Mask?' to type 'Int?'}}{{none}}
+    // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Mask' and 'Int') are expected to be equal}}
+    takeInt_o(mask_o)
+    // expected-error@-1:15 {{cannot convert value of type 'Mask?' to expected argument type 'Int?'}}{{none}}
+    // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Mask' and 'Int') are expected to be equal}}
+
+    // FIXME: No fix-it. Could be 'mask_o?.rawValue' or 'mask_o.map { $0.rawValue }'.
+    let _: UInt64? = mask_o
+    // expected-error@-1:22 {{cannot convert value of type 'Mask?' to specified type 'UInt64?'}}{{28-28=?.rawValue}}
+    takeUInt64_o(mask_o)
+    // expected-error@-1:18 {{cannot convert value of type 'Mask?' to expected argument type 'UInt64?'}}{{none}}
+    // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Mask' and 'UInt64') are expected to be equal}}
+  }
+}
+
+do {
+  class Class {}
+  class SubClass: Class {}
+  struct ClassWrapper : RawRepresentable {
+    var rawValue: Class
+  }
+
+  func takeAnyObject(_: AnyObject) {}
+  func takeAnyObjectOpt(_: AnyObject?) {}
+  func takeSubClass(_: SubClass) {}
+
+  do {
+    let classWrapper: ClassWrapper
+    let subClass: SubClass
+
+    takeAnyObject(classWrapper)
+    // expected-error@-1:19 {{argument type 'ClassWrapper' expected to be an instance of a class or class-constrained type}}{{none}}
+    takeAnyObjectOpt(classWrapper)
+    // expected-error@-1:22 {{argument type 'ClassWrapper' expected to be an instance of a class or class-constrained type}}{{none}}
+
+    // FIXME: Bad fix-it, will not compile
+    takeSubClass(classWrapper)
+    // expected-error@-1:18 {{cannot convert value of type 'ClassWrapper' to expected argument type 'SubClass'}}{{30-30=.rawValue}}
+
+    let iuo: ClassWrapper!
+    takeAnyObject(iuo)
+    // expected-error@-1:19 {{argument type 'ClassWrapper?' expected to be an instance of a class or class-constrained type}}{{none}}
+    takeAnyObjectOpt(iuo)
+    // expected-error@-1:22 {{argument type 'ClassWrapper?' expected to be an instance of a class or class-constrained type}}{{none}}
+
+    let _: ClassWrapper = subClass
+    // expected-error@-1:27 {{cannot convert value of type 'SubClass' to specified type 'ClassWrapper'}}{{27-27=ClassWrapper(rawValue: }} {{35-35=) ?? <#default value#>}}
+    let _: ClassWrapper = classWrapper.rawValue
+    // expected-error@-1:40 {{cannot convert value of type 'Class' to specified type 'ClassWrapper'}}{{27-27=ClassWrapper(rawValue: }} {{48-48=) ?? <#default value#>}}
+
+    // FIXME: This note replaces 'as' with 'as!', which is incorrect.
+    // expected-note@+3:36 {{did you mean to use 'as!' to force downcast?}}{{36-38=as!}}
+    // FIXME: Bad fix-it, will not compile
+    // expected-error@+1:36 {{cannot convert value of type 'AnyObject' to specified type 'ClassWrapper'}}{{27-27=ClassWrapper(rawValue: }} {{48-48=) ?? <#default value#>}}
+    let _: ClassWrapper = subClass as AnyObject
+    // expected-error@-1:36 {{'AnyObject' is not convertible to 'Class'}}{{none}}
+  }
+}
+
+
diff --git a/test/expr/expressions.swift b/test/expr/expressions.swift
index 1e90eaad80b38..878b73a439553 100644
--- a/test/expr/expressions.swift
+++ b/test/expr/expressions.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 //===----------------------------------------------------------------------===//
 // Tests and samples.
@@ -758,10 +758,10 @@ func invalidDictionaryLiteral() {
 //===----------------------------------------------------------------------===//
 // nil/metatype comparisons
 //===----------------------------------------------------------------------===//
-_ = Int.self == nil  // expected-warning {{comparing non-optional value of type 'any (~Copyable & ~Escapable).Type' to 'nil' always returns false}}
-_ = nil == Int.self  // expected-warning {{comparing non-optional value of type 'any (~Copyable & ~Escapable).Type' to 'nil' always returns false}}
-_ = Int.self != nil  // expected-warning {{comparing non-optional value of type 'any (~Copyable & ~Escapable).Type' to 'nil' always returns true}}
-_ = nil != Int.self  // expected-warning {{comparing non-optional value of type 'any (~Copyable & ~Escapable).Type' to 'nil' always returns true}}
+_ = Int.self == nil  // expected-warning {{comparing non-optional value of type 'Int.Type' to 'nil' always returns false}}
+_ = nil == Int.self  // expected-warning {{comparing non-optional value of type 'Int.Type' to 'nil' always returns false}}
+_ = Int.self != nil  // expected-warning {{comparing non-optional value of type 'Int.Type' to 'nil' always returns true}}
+_ = nil != Int.self  // expected-warning {{comparing non-optional value of type 'Int.Type' to 'nil' always returns true}}
 
 _ = Int.self == .none  // expected-warning {{comparing non-optional value of type 'any (~Copyable & ~Escapable).Type' to 'Optional.none' always returns false}}
 _ = .none == Int.self  // expected-warning {{comparing non-optional value of type 'any (~Copyable & ~Escapable).Type' to 'Optional.none' always returns false}}
@@ -794,7 +794,7 @@ func testNilCoalescePrecedence(cond: Bool, a: Int?, r: ClosedRange<Int>?) {
 
   // ?? should have lower precedence than range and arithmetic operators.
   let r1 = r ?? (0...42) // ok
-  let r2 = (r ?? 0)...42 // not ok: expected-error {{binary operator '??' cannot be applied to operands of type 'ClosedRange<Int>?' and 'Int'}}
+  let r2 = (r ?? 0)...42 // not ok: expected-error {{cannot convert value of type 'ClosedRange<Int>?' to expected argument type 'Int?'}}
   let r3 = r ?? 0...42 // parses as the first one, not the second.
   
   
diff --git a/test/expr/postfix/init/unqualified.swift b/test/expr/postfix/init/unqualified.swift
index bb8372378d2c2..9a9824b40e166 100644
--- a/test/expr/postfix/init/unqualified.swift
+++ b/test/expr/postfix/init/unqualified.swift
@@ -7,7 +7,7 @@ class Aaron {
     func foo() {
       // Make sure we recover and assume 'self.init'.
       // expected-error@+2 {{initializer expression requires explicit access; did you mean to prepend it with 'self.'?}} {{11-11=self.}}
-      // expected-error@+1 {{type of expression is ambiguous without a type annotation}}
+      // expected-error@+1 {{failed to produce diagnostic for expression}}
       _ = init
     }
   }
@@ -48,7 +48,7 @@ class Theodosia: Aaron {
 
     // Make sure we recover and assume 'self.init'.
     // expected-error@+2 {{initializer expression requires explicit access; did you mean to prepend it with 'self.'?}} {{22-22=self.}}
-    // expected-error@+1 {{type of expression is ambiguous without a type annotation}}
+    // expected-error@+1 {{failed to produce diagnostic for expression}}
     func foo() { _ = init }
   }
 
diff --git a/test/expr/primary/keypath/keypath-objc.swift b/test/expr/primary/keypath/keypath-objc.swift
index 2bdfbcffdc0a0..34373e2570a8d 100644
--- a/test/expr/primary/keypath/keypath-objc.swift
+++ b/test/expr/primary/keypath/keypath-objc.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library  %s -verify
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -parse-as-library  %s -verify -verify-ignore-unrelated
 import ObjectiveC
 import Foundation
 
diff --git a/test/expr/primary/literal/int.swift b/test/expr/primary/literal/int.swift
new file mode 100644
index 0000000000000..711d7c9dbea13
--- /dev/null
+++ b/test/expr/primary/literal/int.swift
@@ -0,0 +1,18 @@
+// RUN: %target-typecheck-verify-swift
+
+do {
+  func takeInt32(_: Int32) {}
+
+  func f1(_ cint: CInt) {
+    takeInt32(UInt(cint))
+    // expected-error@-1:15 {{cannot convert value of type 'UInt' to expected argument type 'Int32'}}{{15-15=Int32(}}{{25-25=)}}
+  }
+  func f2(_ uint: UInt) {
+    takeInt32(uint)
+    // expected-error@-1:15 {{cannot convert value of type 'UInt' to expected argument type 'Int32'}}{{15-15=Int32(}}{{19-19=)}}
+
+    let int32: Int32 = uint
+    // expected-error@-1:24 {{cannot convert value of type 'UInt' to specified type 'Int32'}}{{24-24=Int32(}}{{28-28=)}}
+  }
+}
+
diff --git a/test/expr/primary/selector/fixits.swift b/test/expr/primary/selector/fixits.swift
index 6608e39fdf123..3ba21c9f0a0cc 100644
--- a/test/expr/primary/selector/fixits.swift
+++ b/test/expr/primary/selector/fixits.swift
@@ -14,22 +14,6 @@
 // Make sure we get the right diagnostics.
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t.overlays) -typecheck %s -verify
 
-// Copy the source, apply the Fix-Its, and compile it again, making
-// sure that we've cleaned up all of the deprecation warnings.
-// RUN: %empty-directory(%t.sources)
-// RUN: %empty-directory(%t.remapping)
-// RUN: cp %s %t.sources/fixits.swift
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t.overlays) -typecheck %t.sources/fixits.swift -fixit-all -emit-fixits-path %t.remapping/fixits.remap
-// RUN: %{python} %utils/apply-fixit-edits.py %t.remapping
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t.overlays) -typecheck %t.sources/fixits.swift -diagnostic-style llvm 2> %t.result
-
-// RUN: %FileCheck %s < %t.result
-// RUN: grep -c "warning:" %t.result | grep 3
-
-// CHECK: warning: no method declared with Objective-C selector 'unknownMethodWithValue:label:'
-// CHECK: warning: string literal is not a valid Objective-C selector
-// CHECK: warning: string literal is not a valid Objective-C selector
-
 import Foundation
 import Helper
 
@@ -83,3 +67,129 @@ func testSelectorConstruction() {
   // Note: from Foundation
   _ = Selector("initWithArray:") // expected-warning{{use '#selector' instead of explicitly constructing a 'Selector'}}{{7-33=#selector(NSSet.init(array:))}}
 }
+
+@objc class Selectors: NSObject {
+  func takeSel(_: Selector) {}
+  @objc func mySel() {}
+  func test() {
+    takeSel("mySel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{13-20=#selector(self.mySel)}}
+    takeSel(Selector("mySel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{13-30=#selector(self.mySel)}}
+  }
+}
+
+@objc class OtherClass: NSObject {
+  func test(s: Selectors) {
+    s.takeSel("mySel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{15-22=#selector(Selectors.mySel)}}
+    s.takeSel(Selector("mySel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{15-32=#selector(Selectors.mySel)}}
+  }
+}
+
+@objc class Base: NSObject {
+  @objc func baseSel() {}
+}
+
+@objc class Outer: NSObject {
+  func takeSel(_: Selector) {}
+  @objc func outerSel() {}
+
+  @objc class Inner: Base {
+    func takeSel(_: Selector) {}
+
+    @objc func innerSel() {}
+
+    func test(s: Selectors, o: Outer) {
+      s.takeSel("mySel")
+      // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{17-24=#selector(Selectors.mySel)}}
+      s.takeSel(Selector("mySel"))
+      // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{17-34=#selector(Selectors.mySel)}}
+
+      takeSel("innerSel")
+      // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{15-25=#selector(self.innerSel)}}
+      takeSel(Selector("innerSel"))
+      // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{15-35=#selector(self.innerSel)}}
+
+      takeSel("baseSel")
+      // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{15-24=#selector(self.baseSel)}}
+      takeSel(Selector("baseSel"))
+      // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{15-34=#selector(self.baseSel)}}
+
+      o.takeSel("outerSel")
+      // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{17-27=#selector(Outer.outerSel)}}
+      o.takeSel(Selector("outerSel"))
+      // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{17-37=#selector(Outer.outerSel)}}
+    }
+  }
+
+  func test(s: Selectors, i: Inner) {
+    s.takeSel("mySel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{15-22=#selector(Selectors.mySel)}}
+    s.takeSel(Selector("mySel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{15-32=#selector(Selectors.mySel)}}
+
+    i.takeSel("innerSel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{15-25=#selector(Inner.innerSel)}}
+    i.takeSel(Selector("innerSel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{15-35=#selector(Inner.innerSel)}}
+
+    i.takeSel("baseSel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{15-24=#selector(Base.baseSel)}}
+    i.takeSel(Selector("baseSel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{15-34=#selector(Base.baseSel)}}
+
+    takeSel("outerSel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{13-23=#selector(self.outerSel)}}
+    takeSel(Selector("outerSel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{13-33=#selector(self.outerSel)}}
+  }
+}
+
+extension Outer {
+  func test2(s: Selectors, i: Inner) {
+    s.takeSel("mySel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{15-22=#selector(Selectors.mySel)}}
+    s.takeSel(Selector("mySel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{15-32=#selector(Selectors.mySel)}}
+
+    i.takeSel("innerSel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{15-25=#selector(Inner.innerSel)}}
+    i.takeSel(Selector("innerSel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{15-35=#selector(Inner.innerSel)}}
+
+    i.takeSel("baseSel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{15-24=#selector(Base.baseSel)}}
+    i.takeSel(Selector("baseSel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{15-34=#selector(Base.baseSel)}}
+
+    takeSel("outerSel")
+    // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{13-23=#selector(self.outerSel)}}
+    takeSel(Selector("outerSel"))
+    // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{13-33=#selector(self.outerSel)}}
+  }
+}
+
+func freeTest(s: Selectors, o: Outer, i: Outer.Inner) {
+  s.takeSel("mySel")
+  // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{13-20=#selector(Selectors.mySel)}}
+  s.takeSel(Selector("mySel"))
+  // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{13-30=#selector(Selectors.mySel)}}
+
+  // FIXME: Fix-it should be 'Outer.Inner.innerSel'.
+  i.takeSel("innerSel")
+  // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{13-23=#selector(Inner.innerSel)}}
+  i.takeSel(Selector("innerSel"))
+  // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{13-33=#selector(Inner.innerSel)}}
+
+  i.takeSel("baseSel")
+  // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{13-22=#selector(Base.baseSel)}}
+  i.takeSel(Selector("baseSel"))
+  // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{13-32=#selector(Base.baseSel)}}
+
+  o.takeSel("outerSel")
+  // expected-warning@-1 {{use of string literal for Objective-C selectors is deprecated; use '#selector' instead}}{{13-23=#selector(Outer.outerSel)}}
+  o.takeSel(Selector("outerSel"))
+  // expected-warning@-1 {{use '#selector' instead of explicitly constructing a 'Selector'}}{{13-33=#selector(Outer.outerSel)}}
+}
diff --git a/test/expr/primary/selector/selector.swift b/test/expr/primary/selector/selector.swift
index 298a037ae54f2..97e2cec4fe46b 100644
--- a/test/expr/primary/selector/selector.swift
+++ b/test/expr/primary/selector/selector.swift
@@ -172,3 +172,21 @@ extension SomeProtocol {
 func test() -> Selector {
   #selector(OverloadedFuncAndProperty.f)
 }
+
+@objc protocol HasThrows {
+  @objc optional func doSomething(to object: AnyObject) throws -> Void
+}
+
+func testWithThrowing(obj: AnyObject) {
+  _ = #selector(HasThrows.doSomething(to:))
+}
+
+@available(SwiftStdlib 5.1, *)
+@objc protocol HasAsync {
+  @objc optional func doSomething(to object: AnyObject) async -> Void
+}
+
+@available(SwiftStdlib 5.1, *)
+func testWithAsync(obj: AnyObject) {
+  _ = #selector(HasAsync.doSomething(to:))
+}
diff --git a/test/expr/print/conditions.swift b/test/expr/print/conditions.swift
index 6e1154d1c2073..4a6d32ebee5dd 100644
--- a/test/expr/print/conditions.swift
+++ b/test/expr/print/conditions.swift
@@ -14,6 +14,18 @@ if (5 + 5) == 9 {
 // CHECK: } else {
 // CHECK: }
 
+if #available(macOS 11, iOS 17, *) {
+} else if #unavailable(watchOS 11) {
+}
+// CHECK: if #available(macOS 11, iOS 17, *) {
+// CHECK: } else if #unavailable(watchOS 11) {
+// CHECK: }
+
+if #_hasSymbol(Int.self) {
+}
+// CHECK: if #_hasSymbol(Int.self) {
+// CHECK: }
+
 guard (5 + 5) == 10 else {
 }
 // CHECK: guard (5 + 5) == 10 else {
diff --git a/test/expr/unary/if_expr.swift b/test/expr/unary/if_expr.swift
index 7ecca30167ab5..f7775d99ff97c 100644
--- a/test/expr/unary/if_expr.swift
+++ b/test/expr/unary/if_expr.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-availability-checking
 
 // MARK: Functions
 
@@ -510,7 +510,7 @@ do {
 
   // FIXME: The type error is likely due to not solving the conjunction before attempting default type var bindings.
   let _ = (if .random() { Int?.none } else { 1 as Int? })?.bitWidth
-  // expected-error@-1 {{type of expression is ambiguous without a type annotation}}
+  // expected-error@-1 {{failed to produce diagnostic for expression}}
   // expected-error@-2 {{'if' may only be used as expression in return, throw, or as the source of an assignment}}
 }
 do {
diff --git a/test/expr/unary/keypath/keypath-availability.swift b/test/expr/unary/keypath/keypath-availability.swift
index bf9ca310827c4..cbcbdbb561870 100644
--- a/test/expr/unary/keypath/keypath-availability.swift
+++ b/test/expr/unary/keypath/keypath-availability.swift
@@ -1,36 +1,128 @@
-// RUN: %target-swift-frontend -target %target-cpu-apple-macosx10.9 -typecheck -verify %s
+// RUN: %target-swift-frontend -typecheck -verify %s
 // REQUIRES: OS=macosx
 
 struct Butt {
-    var setter_conditionally_available: Int {
-        get { fatalError() }
+  var setter_conditionally_available: Int {
+    get { fatalError() }
 
-        @available(macOS 10.10, *)
-        set { fatalError() }
-    }
+    @available(macOS 99, *)
+    set { fatalError() }
+  }
+
+  var setter_unavailable_on_macos: Int {
+    get { fatalError() }
+
+    @available(macOS, unavailable)
+    set { fatalError() }
+  }
+
+  var setter_universally_unavailable: Int {
+    get { fatalError() }
+
+    @available(*, unavailable)
+    set { fatalError() } // expected-note 2 {{setter for 'setter_universally_unavailable' has been explicitly marked unavailable here}}
+  }
+}
+
+@dynamicMemberLookup
+struct Lens<T> {
+  var obj: T
+
+  init(_ obj: T) {
+    self.obj = obj
+  }
+
+  subscript<U>(dynamicMember member: KeyPath<T, U>) -> Lens<U> {
+    get { return Lens<U>(obj[keyPath: member]) }
+  }
+
+  subscript<U>(dynamicMember member: WritableKeyPath<T, U>) -> Lens<U> {
+    get { return Lens<U>(obj[keyPath: member]) }
+    set { obj[keyPath: member] = newValue.obj }
+  }
 }
 
 func assertExactType<T>(of _: inout T, is _: T.Type) {}
 
 @available(macOS 10.9, *)
-public func unavailableSetterContext() {
-    var kp = \Butt.setter_conditionally_available
-    assertExactType(of: &kp, is: KeyPath<Butt, Int>.self)
+public func availableOnMacOS_10_9() {
+  var kp = \Butt.setter_conditionally_available
+  var lens = Lens(Butt())
+  assertExactType(of: &kp, is: KeyPath<Butt, Int>.self)
+  _ = lens.setter_conditionally_available
+  lens.setter_conditionally_available = Lens(1) // expected-error {{cannot assign to property: 'lens' is immutable}}
+}
+
+@available(macOS 99, *)
+public func availableOnMacOS_99() {
+  var kp = \Butt.setter_conditionally_available
+  var lens = Lens(Butt())
+  assertExactType(of: &kp, is: WritableKeyPath<Butt, Int>.self)
+  _ = lens.setter_conditionally_available
+  lens.setter_conditionally_available = Lens(1)
 }
-@available(macOS 10.10, *)
-public func availableSetterContext() {
+
+public func alwaysAvailableOnMacOS() {
+  var lens = Lens(Butt())
+
+  if #available(macOS 99, *) {
     var kp = \Butt.setter_conditionally_available
     assertExactType(of: &kp, is: WritableKeyPath<Butt, Int>.self)
+    _ = lens.setter_conditionally_available
+    // FIXME: [availability] setter_conditionally_available should be writable in this branch
+    lens.setter_conditionally_available = Lens(1) // expected-error {{cannot assign to property: 'lens' is immutable}}
+  } else {
+    var kp = \Butt.setter_conditionally_available
+    assertExactType(of: &kp, is: KeyPath<Butt, Int>.self)
+    _ = lens.setter_conditionally_available
+    lens.setter_conditionally_available = Lens(1) // expected-error {{cannot assign to property: 'lens' is immutable}}
+  }
+
+  var kp2 = \Butt.setter_unavailable_on_macos
+  assertExactType(of: &kp2, is: KeyPath<Butt, Int>.self)
+  _ = lens.setter_unavailable_on_macos
+  lens.setter_unavailable_on_macos = Lens(1) // expected-error {{cannot assign to property: 'lens' is immutable}}
+
+  var kp3 = \Butt.setter_universally_unavailable
+  assertExactType(of: &kp3, is: KeyPath<Butt, Int>.self)
+  _ = lens.setter_universally_unavailable
+  lens.setter_universally_unavailable = Lens(1) // expected-error {{cannot assign to property: 'lens' is immutable}}
 }
-@available(macOS 10.9, *)
-public func conditionalAvailableSetterContext() {
-    if #available(macOS 10.10, *) {
-        var kp = \Butt.setter_conditionally_available
-        assertExactType(of: &kp, is: WritableKeyPath<Butt, Int>.self)
-    } else {
-        var kp = \Butt.setter_conditionally_available
-        assertExactType(of: &kp, is: KeyPath<Butt, Int>.self)
-    }
+
+@available(macOS, unavailable)
+public func unvailableOnMacOS() {
+  var lens = Lens(Butt())
+  var kp = \Butt.setter_conditionally_available
+  assertExactType(of: &kp, is: WritableKeyPath<Butt, Int>.self)
+  _ = lens.setter_conditionally_available
+  lens.setter_conditionally_available = Lens(1)
+
+  var kp2 = \Butt.setter_unavailable_on_macos
+  assertExactType(of: &kp2, is: WritableKeyPath<Butt, Int>.self)
+  _ = lens.setter_unavailable_on_macos
+  lens.setter_unavailable_on_macos = Lens(1)
+
+  var kp3 = \Butt.setter_universally_unavailable
+  assertExactType(of: &kp3, is: KeyPath<Butt, Int>.self)
+  _ = lens.setter_universally_unavailable
+  lens.setter_universally_unavailable = Lens(1) // expected-error {{cannot assign to property: 'lens' is immutable}}
 }
 
-// FIXME: Check additional unavailability conditions
+@available(*, unavailable)
+public func universallyUnavailable() {
+  var lens = Lens(Butt())
+  var kp = \Butt.setter_conditionally_available
+  assertExactType(of: &kp, is: WritableKeyPath<Butt, Int>.self)
+  _ = lens.setter_conditionally_available
+  lens.setter_conditionally_available = Lens(1)
+
+  var kp2 = \Butt.setter_unavailable_on_macos
+  assertExactType(of: &kp2, is: WritableKeyPath<Butt, Int>.self)
+  _ = lens.setter_unavailable_on_macos
+  lens.setter_unavailable_on_macos = Lens(1)
+
+  var kp3 = \Butt.setter_universally_unavailable
+  assertExactType(of: &kp3, is: KeyPath<Butt, Int>.self)
+  _ = lens.setter_universally_unavailable // expected-error {{setter for 'setter_universally_unavailable' is unavailable}}
+  lens.setter_universally_unavailable = Lens(1) // expected-error {{setter for 'setter_universally_unavailable' is unavailable}}
+}
diff --git a/test/expr/unary/keypath/keypath-unsupported-methods.swift b/test/expr/unary/keypath/keypath-unsupported-methods.swift
index 07d6b9aa4ff54..788e612aceff6 100644
--- a/test/expr/unary/keypath/keypath-unsupported-methods.swift
+++ b/test/expr/unary/keypath/keypath-unsupported-methods.swift
@@ -46,3 +46,16 @@ func f_56996() {
   _ = \Int.byteSwapped.signum() // expected-error {{key path cannot refer to instance method 'signum()'}}
   _ = \Int.byteSwapped.init() // expected-error {{key path cannot refer to initializer 'init()'}}
 }
+
+postfix operator ^
+postfix func ^ <T>(_ x: T) -> T { x }
+
+func unsupportedOperator() {
+  struct S {
+    var x: Int
+  }
+  _ = \.^ // expected-error {{invalid component of Swift key path}}
+  _ = \S^ // expected-error {{invalid component of Swift key path}}
+  _ = \S.x^ // expected-error {{invalid component of Swift key path}}
+  _ = \.x^ // expected-error {{invalid component of Swift key path}}
+}
diff --git a/test/expr/unary/keypath/keypath.swift b/test/expr/unary/keypath/keypath.swift
index e58cbe6f79a37..70ddd03b5feb3 100644
--- a/test/expr/unary/keypath/keypath.swift
+++ b/test/expr/unary/keypath/keypath.swift
@@ -865,7 +865,7 @@ func test_keypath_with_method_refs() {
   let _: KeyPath<S, (Int, Int) -> Int> = \.add()
   // expected-error@-1 {{cannot assign value of type 'KeyPath<S, Int>' to type 'KeyPath<S, (Int, Int) -> Int>'}}
   // expected-note@-2 {{arguments to generic parameter 'Value' ('Int' and '(Int, Int) -> Int') are expected to be equal}}
-  let _: KeyPath<S, Int> = \.add() // expected-error {{type of expression is ambiguous without a type annotation}}
+  let _: KeyPath<S, Int> = \.add() // expected-error {{failed to produce diagnostic for expression}}
   let _: KeyPath<S, (Int) -> Int> = \.add(this:)
   let _: KeyPath<S, Int> = \.add(that: 1)
   let _: KeyPath<S, (Int) -> Int> = \.subtract // expected-error {{static member 'subtract' cannot be used on instance of type 'S'}}
@@ -924,10 +924,10 @@ func test_keypath_with_method_refs() {
     subscript(index: Int) -> Int { return index }
   }
 
-  let _: KeyPath<A, Int> = \.foo.bar // expected-error {{type of expression is ambiguous without a type annotation}}
+  let _: KeyPath<A, Int> = \.foo.bar // expected-error {{failed to produce diagnostic for expression}}
   let _: KeyPath<A, Int> = \.faz.bar // expected-error {{static member 'faz()' cannot be used on instance of type 'A'}}
-  let _ = \A.foo.bar // expected-error {{type of expression is ambiguous without a type annotation}}
-  let _ = \A.Type.faz.bar // expected-error {{type of expression is ambiguous without a type annotation}}
+  let _ = \A.foo.bar // expected-error {{failed to produce diagnostic for expression}}
+  let _ = \A.Type.faz.bar // expected-error {{failed to produce diagnostic for expression}}
   let _: KeyPath<A, Int> = \.foo().bar
   let _: KeyPath<A.Type, Int> = \.faz().bar
   let _ = \A.foo().bar
@@ -1429,3 +1429,14 @@ func testKeyPathInout() {
   takesInoutOpt(\.count)
   takesInoutOpt(\String.count)
 }
+
+func testKeypathWithTypeReference() {
+  struct S {
+    enum Q {
+      static let i = 1
+    }
+  }
+  _ = \S.Q.Type.i // okay
+
+  _ = \S.Type.Q // expected-error {{key path cannot refer to type 'Q'}}
+}
\ No newline at end of file
diff --git a/test/expr/unary/keypath/salvage-with-other-type-errors.swift b/test/expr/unary/keypath/salvage-with-other-type-errors.swift
index ea840d762d508..d676ebecd0dd2 100644
--- a/test/expr/unary/keypath/salvage-with-other-type-errors.swift
+++ b/test/expr/unary/keypath/salvage-with-other-type-errors.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // Ensure that key path exprs can tolerate being re-type-checked when necessary
 // to diagnose other errors in adjacent exprs.
diff --git a/test/expr/unary/switch_expr.swift b/test/expr/unary/switch_expr.swift
index 3f976d53deaa6..a23f421451a8e 100644
--- a/test/expr/unary/switch_expr.swift
+++ b/test/expr/unary/switch_expr.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-availability-checking
 
 // MARK: Functions
 
@@ -670,7 +670,7 @@ do {
 
   // FIXME: The type error is likely due to not solving the conjunction before attempting default type var bindings.
   let _ = (switch Bool.random() { case true: Int?.none case false: 1 })?.bitWidth
-  // expected-error@-1 {{type of expression is ambiguous without a type annotation}}
+  // expected-error@-1 {{failed to produce diagnostic for expression}}
   // expected-error@-2 {{'switch' may only be used as expression in return, throw, or as the source of an assignment}}
 }
 do {
diff --git a/test/lit.cfg b/test/lit.cfg
index fcfbb61aceea5..d0016388f1c30 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -186,8 +186,10 @@ kIsAndroid = 'ANDROID_DATA' in os.environ
 
 # Choose between lit's internal shell pipeline runner and a real shell.  If
 # LIT_USE_INTERNAL_SHELL is in the environment, we use that as an override.
-use_lit_shell = os.environ.get('LIT_USE_INTERNAL_SHELL', kIsWindows)
+use_lit_shell = os.environ.get('LIT_USE_INTERNAL_SHELL', kIsWindows or lit_config.update_tests)
 if not use_lit_shell:
+    if lit_config.update_tests:
+        lit_config.fatal('--update-tests cannot be combined with LIT_USE_INTERNAL_SHELL=0')
     config.available_features.add('shell')
 
 config.test_format = swift_test.SwiftTest(coverage_mode=config.coverage_mode,
@@ -234,7 +236,7 @@ elif platform.system() == 'Darwin':
     if not llvm_libs_dir:
         lit_config.fatal('No LLVM libs dir set.')
     lto_flags = "-Xlinker -lto_library -Xlinker %s/libLTO.dylib" % llvm_libs_dir
-    use_just_built_liblto = "LIBLTO_PATH=%s/libLTO.dylib" % llvm_libs_dir
+    use_just_built_liblto = "env LIBLTO_PATH=%s/libLTO.dylib" % llvm_libs_dir
 
 config.substitutions.append( ('%lto_flags', lto_flags) )
 config.substitutions.append( ('%use_just_built_liblto', use_just_built_liblto) )
@@ -345,6 +347,7 @@ config.llvm_dis = inferSwiftBinary('llvm-dis')
 config.llvm_nm = inferSwiftBinary('llvm-nm')
 config.llvm_readtapi = inferSwiftBinary('llvm-readtapi')
 config.llvm_size = inferSwiftBinary('llvm-size')
+config.yaml2obj = inferSwiftBinary('yaml2obj')
 config.sourcekitd_test = inferSwiftBinary('sourcekitd-test')
 config.complete_test = inferSwiftBinary('complete-test')
 config.swift_api_digester = inferSwiftBinary('swift-api-digester')
@@ -409,10 +412,10 @@ if run_vers.endswith('-simulator'):
 else:
     run_environment=''
 
-# Don't distinguish between wasi, wasip1, and so on to use OS=wasi condition in
-# the test suites.
-if run_os.startswith('wasi'):
-    run_os = 'wasi'
+# Allow using using same condition in WASI test suites.
+kIsWASI = run_os.startswith('wasi')
+if kIsWASI:
+  run_os = f"{run_os}{run_vers}"
 
 # Parse the host triple
 (host_cpu, host_vendor, host_os, host_vers) = re.match('([^-]+)-([^-]+)-([^0-9-]+)(.*)', config.host_triple).groups()
@@ -502,7 +505,7 @@ def availability_macro_to_swift_abi_target_triple(macro):
     # Use a regex and split to pull out the components of an availability macro
     # that is formatted like this:
     #    SwiftStdlib 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2
-    matches = re.search(r'^[\s]*SwiftStdlib[\s]+([0-9\.]+)[\s]*:[\s]*(.+)', macro)
+    matches = re.search(r'^[\s]*Swift(?:Stdlib|CompatibilitySpan)[\s]+([0-9\.]+)[\s]*:[\s]*(.+)', macro)
     stdlib_vers = matches.group(1)
     vers_by_platform = {}
     for platform_vers in matches.group(2).split(', '):
@@ -530,11 +533,59 @@ def availability_macro_to_swift_abi_target_triple(macro):
     return stdlib_vers, '%s-%s-%s%s%s' % (run_cpu, run_vendor, run_os,
                                           os_vers, run_environment)
 
+# Compare two version numbers
+def version_gt(a, b):
+  a_int = list(map(int, a.split(".")))
+  b_int = list(map(int, b.split(".")))
+  vlen = max(len(a_int), len(b_int))
+  if len(a_int) < vlen:
+    a_int += [0] * (vlen - len(a_int))
+  if len(b_int) < vlen:
+    b_int += [0] * (vlen - len(b_int))
+  return a_int > b_int
+
+# Returns a StdlibDeploymentTarget macro given a SwiftStdlib macro
+def availability_macro_to_current(macro):
+    matches = re.search(r'^\s*SwiftStdlib\s+([0-9\.]*)\s*:\s*(.*)', macro)
+    if not matches:
+        return None
+
+    stdlib_vers = matches.group(1)
+    orig_spec = matches.group(2)
+
+    vers_by_platform = {}
+    for platform_vers in orig_spec.split(', '):
+        components = platform_vers.split(' ')
+        vers_by_platform[components[0]] = components[1]
+
+    platform_name = {
+        'macosx': 'macOS',
+        'ios': 'iOS',
+        'maccatalyst': 'iOS',
+        'tvos': 'tvOS',
+        'watchos': 'watchOS'
+    }.get(run_os)
+
+    orig_vers = vers_by_platform.get(platform_name)
+    if orig_vers is not None and orig_vers != "9999":
+      ver = platform.mac_ver()[0]
+
+      if version_gt(orig_vers, ver):
+        return f"StdlibDeploymentTarget {stdlib_vers}:{platform_name} {ver}"
+
+    return f"StdlibDeploymentTarget {stdlib_vers}:{orig_spec}"
+
 # Add availability macros to the default frontend/driver flags and create target
 # triple substitutions for each stdlib version.
 for macro in load_availability_macros():
     config.swift_frontend_test_options += " -define-availability '{0}'".format(macro)
     config.swift_driver_test_options += " -Xfrontend -define-availability -Xfrontend '{0}'".format(macro)
+
+    current_macro = availability_macro_to_current(macro)
+    if current_macro:
+      config.swift_frontend_test_options += " -define-availability '{0}'".format(current_macro)
+      config.swift_driver_test_options += " -Xfrontend -define-availability -Xfrontend '{0}'".format(current_macro)
+
     (stdlib_vers, triple) = availability_macro_to_swift_abi_target_triple(macro)
     config.substitutions.append(('%target-swift-{}-abi-triple'.format(stdlib_vers), triple))
 
@@ -697,6 +748,7 @@ config.substitutions.append( ('%llvm-dis', config.llvm_dis) )
 config.substitutions.append( ('%llvm-nm', config.llvm_nm) )
 config.substitutions.append( ('%llvm-readtapi', config.llvm_readtapi) )
 config.substitutions.append( ('%llvm-size', config.llvm_size) )
+config.substitutions.append( ('%yaml2obj', config.yaml2obj) )
 config.substitutions.append( ('%swift-demangle-yamldump', config.swift_demangle_yamldump) )
 config.substitutions.append( ('%swift-demangle', config.swift_demangle) )
 config.substitutions.append( ('%Benchmark_O', config.benchmark_o) )
@@ -707,6 +759,8 @@ config.substitutions.append( ('%swift-path', config.swift) )
 config.substitutions.append( ('%swift-plugin-server', config.swift_plugin_server) )
 config.substitutions.append( ('%swift-parse-test', config.swift_parse_test) )
 config.substitutions.append( ('%swift-scan-test', config.swift_scan_test) )
+config.substitutions.append( ('%swift-symbolgraph-extract', config.swift_symbolgraph_extract) )
+config.substitutions.append( ('%swift-synthesize-interface', config.swift_synthesize_interface) )
 config.substitutions.append( ('%validate-json', f"{config.python} -m json.tool") )
 
 config.clang_include_dir = make_path(config.llvm_obj_root, 'include')
@@ -789,6 +843,11 @@ config.substitutions.append( ('%clangxx',
                               "%r %s" %
                                 (config.clangxx, clang_mcp_opt)) )
 
+# Alternative to %clang that doesn't require -fmodules.
+config.substitutions.append( ('%clang-no-modules',
+                              "%r" %
+                                (config.clang)) )
+
 # This must come after all substitutions containing "%clang".
 # Note: %clang is the locally-built clang.
 # To get Xcode's clang, use %target-clang.
@@ -852,6 +911,11 @@ config.available_features.add("SWIFT_VERSION=" + swift_version)
 
 config.available_features.add("STDLIB_VARIANT={}".format(config.variant_suffix[1:]))
 
+if "target-same-as-host" in config.available_features:
+    # Only add SWIFT_SDKS features if we're building host tools
+    for sdk in config.swift_sdks:
+        config.available_features.add("SWIFT_SDK=" + sdk.lower())
+
 if "optimized_stdlib" in config.available_features:
   config.available_features.add("optimized_stdlib_" + run_cpu)
 
@@ -865,6 +929,11 @@ if swift_test_mode == 'optimize_none':
     # optimize mode for a cpu.
     config.available_features.add("swift_test_mode_optimize_none_" + run_cpu)
     swift_execution_tests_extra_flags = ''
+elif swift_test_mode == 'optimize_none_with_opaque_values':
+    config.available_features.add("executable_test")
+    config.limit_to_features.add("executable_test")
+    config.available_features.add("swift_test_mode_optimize_none_with_opaque_values")
+    swift_execution_tests_extra_flags = '-Xfrontend -enable-sil-opaque-values'
 elif swift_test_mode == 'optimize_none_with_implicit_dynamic':
     config.available_features.add("executable_test")
     config.limit_to_features.add("executable_test")
@@ -936,7 +1005,7 @@ elif swift_test_subset == 'only_stress':
     config.limit_to_features.add("stress_test")
     config.limit_to_features.discard("executable_test")
 else:
-    lit_config.fatal("Unknown test mode %r" % swift_test_subset)
+    lit_config.fatal("Unknown test subset %r" % swift_test_subset)
 
 if 'swift_evolve' in lit_config.params:
     config.available_features.add("swift_evolve")
@@ -1185,19 +1254,26 @@ def use_interpreter_for_simple_runs():
         # path.
         result += (
             'env SWIFT_INTERPRETER=%r %s %r %s -module-name main %s %s %s '
-            % (config.swift, xcrun_prefix, config.swift, target_options,
-               config.swift_test_options,
-               config.swift_driver_test_options,
-               swift_execution_tests_extra_flags))
+            % (
+                escape_for_substitute_captures(config.swift),
+                escape_for_substitute_captures(xcrun_prefix),
+                escape_for_substitute_captures(config.swift),
+                escape_for_substitute_captures(target_options),
+                escape_for_substitute_captures(config.swift_test_options),
+                escape_for_substitute_captures(config.swift_driver_test_options),
+                escape_for_substitute_captures(swift_execution_tests_extra_flags)
+            )
+        )
         if stdlib:
             result += '-Xfrontend -disable-access-control '
         if parameterized:
-            result += ' \\1 '
+            result += r' \1 '
         if gyb:
             result += '%t/main.swift'
         else:
             result += '%s'
-        return result
+        return SubstituteCaptures(result)
+
     config.target_run_stdlib_swiftgyb = make_simple_target_run(gyb=True)
     config.target_run_simple_swiftgyb = make_simple_target_run(gyb=True)
     config.target_run_stdlib_swift = make_simple_target_run(stdlib=True)
@@ -1207,10 +1283,11 @@ def use_interpreter_for_simple_runs():
     config.target_run_simple_swiftgyb_parameterized = make_simple_target_run(gyb=True, parameterized=True)
     config.available_features.add('interpret')
 
-target_specific_module_triple = config.variant_triple
+target_specific_module_triple = config.variant_module_triple
 target_future = target_specific_module_triple
 
 config.target_run = ''
+config.target_not_crash = 'not --crash'
 config.target_rtti_opt = '-fno-rtti'
 config.target_pic_opt = ''
 config.target_cxx_lib = '-lc++'
@@ -1219,12 +1296,10 @@ config.target_static_library_prefix = 'lib'
 config.target_static_library_suffix = '.a'
 config.target_env_prefix = ''
 config.target_sdk_libcxx_path = ''
+config.target_clang_resource_dir_opt = ''
+config.target_swift_default_executor_opt = '-lswift_ConcurrencyDefaultExecutor'
 
 if run_vendor == 'apple':
-    target_specific_module_triple = '{}-apple-{}'.format(
-        { 'aarch64': 'arm64', 'amd64': 'x86_64' }.get(run_cpu, run_cpu),
-        { 'macosx': 'macos', 'darwin': 'macos' }.get(run_os, run_os)
-    )
 
     config.target_object_format = "macho"
     config.target_shared_library_prefix = 'lib'
@@ -1423,8 +1498,6 @@ if run_vendor == 'apple':
             xcrun_sdk_name = "appletvsimulator"
             target_future_version = "99.99.0"
 
-        target_specific_module_triple += "-simulator"
-
         config.target_env_prefix = 'SIMCTL_CHILD_'
 
         config.target_cc_options = (
@@ -1592,11 +1665,12 @@ if run_vendor == 'apple':
         "%s %s %s" %
         (xcrun_prefix, config.clangxx, config.target_cc_options))
 
-    config.target_build_swift_dylib = (
-        "%s -parse-as-library -emit-library -o '\\1' "
-        "-Xlinker -install_name -Xlinker @executable_path/$(basename '\\1')"
-        % (config.target_build_swift))
-    config.target_add_rpath = r'-Xlinker -rpath -Xlinker \1'
+    config.target_build_swift_dylib = SubstituteCaptures(
+        f"{escape_for_substitute_captures(config.target_build_swift)}"
+        r" -parse-as-library -emit-library -o '\1\2'"
+        r" -Xlinker -install_name -Xlinker @executable_path/\2"
+    )
+    config.target_add_rpath = SubstituteCaptures(r'-Xlinker -rpath -Xlinker \1')
 
     target_future = format('%s-apple-%s%s%s' % (run_cpu, run_os, target_future_version, run_environment))
 
@@ -1692,7 +1766,7 @@ elif run_os in ['windows-msvc']:
     subst_target_swift_frontend_mock_sdk_after = ''
 
     config.target_build_swift_dylib =                                            \
-            SubstituteCaptures(r"%s -parse-as-library -emit-library -o \1" % (
+            SubstituteCaptures(r"%s -parse-as-library -emit-library -o \1\2" % (
                 escape_for_substitute_captures(config.target_build_swift)))
     config.target_add_rpath = r''
 
@@ -1828,10 +1902,11 @@ elif (run_os in ['linux-gnu', 'linux-gnueabihf', 'freebsd', 'openbsd', 'windows-
            config.swift_test_options, config.swift_driver_test_options,
            swift_execution_tests_extra_flags))
     config.target_codesign = "echo"
-    config.target_build_swift_dylib = (
-        "%s -parse-as-library -emit-library -o '\\1'"
-        % (config.target_build_swift))
-    config.target_add_rpath = r'-Xlinker -rpath -Xlinker \1'
+    config.target_build_swift_dylib = SubstituteCaptures(
+        f"{escape_for_substitute_captures(config.target_build_swift)}"
+        r" -parse-as-library -emit-library -o '\1\2'"
+    )
+    config.target_add_rpath = SubstituteCaptures(r'-Xlinker -rpath -Xlinker \1')
     config.target_swift_frontend = (
         '%s -target %s %s %s %s %s '
         % (config.swift_frontend, config.variant_triple, config.resource_dir_opt, mcp_opt,
@@ -1921,11 +1996,11 @@ elif run_os == 'linux-androideabi' or run_os == 'linux-android':
         config.resource_dir_opt, mcp_opt, config.swift_test_options,
         config.swift_driver_test_options, swift_execution_tests_extra_flags])
     config.target_codesign = "echo"
-    config.target_build_swift_dylib = ' '.join([
-        config.target_build_swift,
-        '-parse-as-library', '-emit-library',
-        '-o', "'\\1'"])
-    config.target_add_rpath = r'-Xlinker -rpath -Xlinker \1'
+    config.target_build_swift_dylib = SubstituteCaptures(
+        f"{escape_for_substitute_captures(config.target_build_swift)}"
+        r" -parse-as-library -emit-library -o '\1\2'"
+    )
+    config.target_add_rpath = SubstituteCaptures(r'-Xlinker -rpath -Xlinker \1')
     config.target_swift_frontend = ' '.join([
         config.swift_frontend,
         '-target', config.variant_triple,
@@ -1986,7 +2061,7 @@ elif run_os == 'linux-androideabi' or run_os == 'linux-android':
         '-L%s' % make_path(test_resource_dir, config.target_sdk_name)])
     # The Swift interpreter is not available when targeting Android.
     config.available_features.discard('swift_interpreter')
-elif run_os == 'wasi':
+elif kIsWASI:
     lit_config.note("Testing WebAssembly/WASI " + config.variant_triple)
 
     config.target_object_format = "wasm"
@@ -1994,6 +2069,9 @@ elif run_os == 'wasi':
     config.target_shared_library_suffix = ".a"
     config.target_sdk_name = "wasi"
     config.target_runtime = "native"
+    config.target_not_crash = "not"
+    config.target_clang_resource_dir_opt = f"-resource-dir {test_resource_dir}/../../../wasi-sysroot/wasm32-wasip1"
+    config.target_swift_default_executor_opt = ''
 
     config.target_swift_autolink_extract = inferSwiftBinary("swift-autolink-extract")
 
@@ -2005,9 +2083,10 @@ elif run_os == 'wasi':
         mcp_opt, config.swift_test_options,
         config.swift_driver_test_options, swift_execution_tests_extra_flags])
     config.target_codesign = "echo"
-    config.target_build_swift_dylib = (
-        "%s -parse-as-library -emit-library -static -o '\\1'"
-        % (config.target_build_swift))
+    config.target_build_swift_dylib = SubstituteCaptures(
+        f"{escape_for_substitute_captures(config.target_build_swift)}"
+        r" -parse-as-library -emit-library -static -o '\1\2'"
+    )
     config.target_add_rpath = ''
     config.target_swift_frontend = ' '.join([
         config.swift_frontend,
@@ -2063,7 +2142,7 @@ elif run_os == 'wasi':
 
 elif config.external_embedded_platform:
     lit_config.note("Testing embedded platform " + config.variant_triple)
-    
+
     config.target_object_format = "elf"
     config.target_sdk_name = "embedded"
     config.target_runtime = "native"
@@ -2088,9 +2167,10 @@ elif config.external_embedded_platform:
         mcp_opt, config.swift_test_options,
         config.swift_driver_test_options, swift_execution_tests_extra_flags])
     config.target_codesign = "echo"
-    config.target_build_swift_dylib = (
-        "%s -parse-as-library -emit-library -static -o '\\1'"
-        % (config.target_build_swift))
+    config.target_build_swift_dylib = SubstituteCaptures(
+        f"{escape_for_substitute_captures(config.target_build_swift)}"
+        r" -parse-as-library -emit-library -static -o '\1\2'"
+    )
     config.target_add_rpath = ''
     config.target_swift_frontend = ' '.join([
         config.swift_frontend,
@@ -2227,7 +2307,44 @@ concurrency_back_deploy_path = ''
 if run_vendor == 'apple':
     if 'back_deploy_concurrency' in lit_config.params:
         config.available_features.add('back_deploy_concurrency')
-        concurrency_back_deploy_path = os.path.join(os.path.dirname(swift_obj_root), os.path.basename(swift_obj_root).replace("swift-", "backdeployconcurrency-"), 'lib', 'swift-5.5', xcrun_sdk_name)
+        toolchain_swiftc_path = subprocess.check_output(['xcrun', '--find', 'swiftc']).rstrip().decode('utf-8')
+        concurrency_back_deploy_path =  os.path.join(os.path.dirname(toolchain_swiftc_path), '..', 'lib', 'swift-5.5', xcrun_sdk_name)
+        if not os.path.isdir(concurrency_back_deploy_path):
+            lit_config.fatal(f"Concurrency back deploy libraries not found at {concurrency_back_deploy_path}")
+
+compatibility_span_back_deploy_path = ''
+if run_vendor == 'apple':
+    COMPATIBILITY_SPAN_BACK_DEPLOY_EARLIEST_VERSIONS = {
+        'macosx': '10.14.4',
+        'ios': '12.2',
+        'maccatalyst': '13.1',
+        'tvos': '12.2',
+        'watchos': '5.2',
+        'xros': '1.0',
+    }
+
+    compatibility_span_back_deploy_version = tuple(
+        int(component) for component
+        in COMPATIBILITY_SPAN_BACK_DEPLOY_EARLIEST_VERSIONS.get(run_os, '').split('.'))
+
+    tuple_run_vers=tuple(int(component) for component in run_vers.split('.'))
+
+    if tuple_run_vers >= compatibility_span_back_deploy_version and tuple_run_vers < (26,):
+        config.available_features.add('back_deploy_compatibility_span')
+        toolchain_swiftc_path = subprocess.check_output(['xcrun', '--find', 'swiftc']).rstrip().decode('utf-8')
+        compatibility_span_back_deploy_path = os.path.join(
+            os.path.dirname(toolchain_swiftc_path), '..',
+            'lib', 'swift-6.2', xcrun_sdk_name)
+        if not os.path.isdir(compatibility_span_back_deploy_path):
+            lit_config.warning(
+                "Compatibility span back deploy libraries not found at "
+                f"{compatibility_span_back_deploy_path}. Falling back to local build...")
+            compatibility_span_back_deploy_path = os.path.join(
+                config.swift_lib_dir, 'swift-6.2', xcrun_sdk_name)
+            if not os.path.isdir(compatibility_span_back_deploy_path):
+                lit_config.fatal(
+                  "Compatibility span back deploy libraries "
+                  f"not found at {compatibility_span_back_deploy_path}")
 
 backtracer_path = make_path(config.swift_libexec_dir, 'swift',
                             config.target_sdk_name, 'swift-backtrace')
@@ -2317,6 +2434,9 @@ def configure_remote_run():
         if concurrency_back_deploy_path and 'use_os_stdlib' in lit_config.params:
             upload_dylibs(concurrency_back_deploy_path)
 
+        if compatibility_span_back_deploy_path and 'use_os_stdlib' in lit_config.params:
+            upload_dylibs(compatibility_span_back_deploy_path)
+
         # FIXME: Uploading specific files in bin/ is not very scalable.
         local_swift_reflection_test = lit.util.which(
             swift_reflection_test_name, config.environment['PATH'])
@@ -2400,10 +2520,15 @@ def find_compiler_rt_libs():
     # Next check for the old scheme 'clang/lib/<os-name>', ignoring
     # any target environment which is currently part of 'run_os'.
     path = make_path(base, run_os.split('-')[0])
+
+    # Check if the Android environment needs to be in the name.
+    env = ''
+    if run_os.startswith('linux-android'):
+        env = '-android'
     if os.path.exists(path):
         # We should then have the architecture in the name.
         for lib in os.listdir(path):
-            match = re.match(r'(?:lib)?clang_rt\.(\w+)-' + run_cpu, lib)
+            match = re.match(r'(?:lib)?clang_rt\.(\w+)-' + run_cpu + env, lib)
             if match:
                 libs[match[1]] = lib
 
@@ -2453,19 +2578,16 @@ check_runtime_libs(runtime_libs)
 
 config.substitutions.append(('%target-objc-interop', run_objc_interop))
 
-# For testing the remote-run utility itself, see if we can find an sftp-server
-# binary.
-def find_sftp_server():
-    paths_to_try = ['/usr/libexec/sftp-server', '/usr/lib/sftp-server',
-                    '/usr/libexec/openssh/sftp-server',
-                    '/usr/lib/openssh/sftp-server']
-    return next((path for path in paths_to_try if os.path.isfile(path)), None)
 
-sftp_server_path = find_sftp_server()
-if sftp_server_path:
-    config.available_features.add('sftp_server')
-config.substitutions.append(('%sftp-server',
-                             sftp_server_path or 'no-sftp-server'))
+def find_rsync():
+    for path in os.getenv("PATH").split(":"):
+        rsync_path = os.path.join(path, "rsync")
+        if os.path.isfile(rsync_path):
+            return rsync_path
+
+
+if find_rsync():
+    config.available_features.add("rsync")
 
 subst_target_repl_run_simple_swift = ""
 if 'swift_repl' in config.available_features:
@@ -2576,7 +2698,7 @@ if run_vendor != 'apple':
 
 if 'remote_run_host' in lit_config.params:
     configure_remote_run()
-elif not kIsWindows and not run_os == 'wasi':
+elif not kIsWindows and not kIsWASI:
     if 'use_os_stdlib' in lit_config.params:
         config.available_features.add('use_os_stdlib')
 
@@ -2742,6 +2864,8 @@ extraCheckWarningFlags = (
 # Verifies that a C++ file can be compiled without warnings except for some exceptions.
 config.substitutions.insert(0, ('%check-c-header-in-clang',
   '%clang -fsyntax-only -x c-header ' + extraCheckWarningFlags +
+  ' --sysroot %r ' % config.variant_sdk +
+  '-target %r ' % config.variant_triple +
   # Use standard header/framework search paths.
   '-F %%clang-importer-sdk-path/frameworks '
   '-I %%clang-include-dir '
@@ -2751,6 +2875,7 @@ config.substitutions.insert(0, ('%check-c-header-in-clang',
 config.substitutions.insert(0, ('%check-cxx-header-in-clang',
   '%clangxx -fsyntax-only -x c++-header ' + extraCheckWarningFlags +
   ' --sysroot %r ' % config.variant_sdk +
+  '-target %r ' % config.variant_triple +
   # Use standard header/framework search paths.
   '-F %%clang-importer-sdk-path/frameworks '
   '-I %%clang-include-dir %%cxx-stdlib-include '
@@ -2815,7 +2940,10 @@ config.substitutions.append(('%target-run-stdlib-swift', config.target_run_stdli
 config.substitutions.append(('%target-repl-run-simple-swift', subst_target_repl_run_simple_swift))
 config.substitutions.append(('%target-run', config.target_run))
 config.substitutions.append(('%target-jit-run', subst_target_jit_run))
-config.substitutions.append(('%target-build-swift-dylib\(([^)]+)\)', config.target_build_swift_dylib))
+# Capture groups:
+# \1 = path before the file name (non-greedy)
+# \2 = file name (last component, no slashes or parentheses)
+config.substitutions.append(('%target-build-swift-dylib\(([^)]+?)([^/\\()]+)\)', config.target_build_swift_dylib))
 config.substitutions.append(('%target-codesign', config.target_codesign))
 config.substitutions.append(('%target-build-swift', config.target_build_swift))
 config.substitutions.append(('%target-clang', config.target_clang))
@@ -2952,14 +3080,16 @@ config.substitutions.insert(0, ('%target-static-library-name\(([^)]+)\)',
                                 SubstituteCaptures(r'%s\1%s' % (
                                     escape_for_substitute_captures(config.target_static_library_prefix),
                                     escape_for_substitute_captures(config.target_static_library_suffix)))))
-config.substitutions.append(('%target-rpath\(([^)]+)\)',
-                             SubstituteCaptures(config.target_add_rpath)))
+config.substitutions.append(('%target-rpath\(([^)]+)\)', config.target_add_rpath))
 
 config.substitutions.append(('%target-resilience-test', config.target_resilience_test))
 
 config.substitutions.append(('%llvm-profdata', config.llvm_profdata))
 config.substitutions.append(('%llvm-cov', config.llvm_cov))
 config.substitutions.append(('%hmaptool', os.path.join(config.llvm_src_root, '..', 'clang', 'utils', 'hmaptool', 'hmaptool')))
+config.substitutions.append(('%target-not-crash', config.target_not_crash))
+config.substitutions.insert(0, ('%target-clang-resource-dir-opt', config.target_clang_resource_dir_opt))
+config.substitutions.insert(0, ('%target-swift-default-executor-opt', config.target_swift_default_executor_opt))
 
 # Set up the host library environment.
 if hasattr(config, 'target_library_path_var'):
@@ -3081,7 +3211,7 @@ def linux_get_os_release():
     return os_id, os_release
 
 if platform.system() == 'Linux':
-    # Retrieve the Linux distro and version from `/etc/os-release`. 
+    # Retrieve the Linux distro and version from `/etc/os-release`.
     (distributor, release) = linux_get_os_release()
     if distributor == '' or release == '':
         # If `/etc/os-release` does not provide full results, fallback to `lsb_release`.
@@ -3156,5 +3286,7 @@ visual_studio_version = os.environ.get('VisualStudioVersion')
 if kIsWindows and visual_studio_version:
   config.available_features.add('MSVC_VER=%s' % visual_studio_version)
 
+lit_config.note(f"Target Triple: {config.target_triple}, Variant Triple: {config.variant_triple}, Module Triple: {config.variant_module_triple}")
+
 lit_config.note("Available features: " + ", ".join(sorted(config.available_features)))
 config.substitutions.append( ('%use_no_opaque_pointers', '-Xcc -Xclang -Xcc -no-opaque-pointers' ) )
diff --git a/test/lit.site.cfg.in b/test/lit.site.cfg.in
index 14f57fe1b0680..4da78ee4d43ec 100644
--- a/test/lit.site.cfg.in
+++ b/test/lit.site.cfg.in
@@ -28,6 +28,7 @@ config.swift_src_root = lit_config.params.get("swift_src_root", "@SWIFT_SOURCE_D
 config.swift_obj_root = "@SWIFT_BINARY_DIR@"
 config.target_triple = "@LLVM_TARGET_TRIPLE@"
 config.variant_triple = "@VARIANT_TRIPLE@"
+config.variant_module_triple = "@VARIANT_MODULE_TRIPLE@"
 config.variant_sdk = "@VARIANT_SDK@"
 config.variant_suffix = "@VARIANT_SUFFIX@"
 config.external_embedded_platform = "@VARIANT_EXTERNAL_EMBEDDED_PLATFORM@" == "TRUE"
@@ -143,7 +144,7 @@ if "@SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED@" == "TRUE":
     config.available_features.add('distributed')
 if "@SWIFT_STDLIB_STATIC_PRINT@" == "TRUE":
     config.available_features.add('stdlib_static_print')
-if "@SWIFT_STDLIB_ENABLE_UNICODE_DATA" == "TRUE":
+if "@SWIFT_STDLIB_ENABLE_UNICODE_DATA@" == "TRUE":
     config.available_features.add('stdlib_unicode_data')
 if "@SWIFT_ENABLE_EXPERIMENTAL_STRING_PROCESSING@" == "TRUE":
     config.available_features.add('string_processing')
@@ -173,6 +174,8 @@ config.freestanding_sdk_name = "@SWIFT_SDK_FREESTANDING_LIB_SUBDIR@"
 if '@SWIFT_BUILD_SWIFT_SYNTAX@' == 'TRUE':
   config.available_features.add('swift_swift_parser')
 
+config.swift_sdks = "@SWIFT_SDKS@".split(";")
+
 # Let the main config do the real work.
 if config.test_exec_root is None:
     config.test_exec_root = os.path.dirname(lit.util.abs_path_preserve_drive(__file__))
diff --git a/test/multifile/Inputs/protocol-conformance-redundant-def.swift b/test/multifile/Inputs/protocol-conformance-redundant-def.swift
index 0bdd9edb2ad0f..05552f2f0a9d9 100644
--- a/test/multifile/Inputs/protocol-conformance-redundant-def.swift
+++ b/test/multifile/Inputs/protocol-conformance-redundant-def.swift
@@ -5,3 +5,11 @@ public protocol Hello {
 open class Super {
   public init() {}
 }
+
+open class GenericSuperClass<T> {
+  public init() {}
+}
+
+public struct GenericStruct<T> {
+  public init() {}
+}
\ No newline at end of file
diff --git a/test/multifile/Inputs/protocol-conformance-redundant-ext.swift b/test/multifile/Inputs/protocol-conformance-redundant-ext.swift
index 84c34532ddb20..19e45986d15cb 100644
--- a/test/multifile/Inputs/protocol-conformance-redundant-ext.swift
+++ b/test/multifile/Inputs/protocol-conformance-redundant-ext.swift
@@ -1,7 +1,19 @@
 import Def
 
-extension Super : Hello {
+extension Super: @retroactive Hello {
   public func hello() {
-    print("Hello")
+    print("Hello from Ext")
+  }
+}
+
+extension GenericSuperClass: @retroactive Hello {
+  public func hello() {
+    print("Hello from Ext")
+  }
+}
+
+extension GenericStruct: @retroactive Hello {
+  public func hello() {
+    print("Hello from Ext")
   }
 }
diff --git a/test/multifile/protocol-conformance-redundant.swift b/test/multifile/protocol-conformance-redundant.swift
index 9a8814221e264..0eba7ae78583a 100644
--- a/test/multifile/protocol-conformance-redundant.swift
+++ b/test/multifile/protocol-conformance-redundant.swift
@@ -3,14 +3,11 @@
 // RUN: %target-build-swift-dylib(%t/%target-library-name(Ext)) -module-name Ext -emit-module -emit-module-path %t/Ext.swiftmodule -I%t -L%t -lDef %S/Inputs/protocol-conformance-redundant-ext.swift
 // RUN: %target-build-swift -I%t -L%t -lDef -o %t/main %target-rpath(%t) %s
 // RUN: %target-codesign %t/main %t/%target-library-name(Def) %t/%target-library-name(Ext)
-// RUN: %target-run %t/main %t/%target-library-name(Def) %t/%target-library-name(Ext) 2>&1 | %FileCheck %s
+// RUN: %target-run %t/main %t/%target-library-name(Def) %t/%target-library-name(Ext) 2> >(%FileCheck %s -check-prefix=CHECK-STDERR) | %FileCheck %s
 
 // REQUIRES: executable_test
 // XFAIL: OS=windows-msvc
 
-// CHECK: Warning: 'main.Sub' conforms to protocol 'Hello', but it also inherits conformance from 'Def.Super'.  Relying on a particular conformance is undefined behaviour.
-// CHECK: Hello
-
 import StdlibUnittest
 
 #if canImport(Darwin)
@@ -35,7 +32,40 @@ class Sub : Super, Hello {
   }
 }
 
+// CHECK-STDERR: Warning: 'main.Sub' conforms to protocol 'Hello', but it also inherits conformance from 'Def.Super'.  Relying on a particular conformance is undefined behaviour.
 let s = Sub() as AnyObject as! Hello
-
+// CHECK: Hello
 s.hello()
 
+extension GenericStruct: @retroactive Hello where T == String {
+  public func hello() {
+    print("Hello from main")
+  }
+}
+
+// CHECK-STDERR: Warning: 'main.GenericSubClass<Swift.String>' conforms to protocol 'Hello', but it also inherits conformance from 'Def.GenericSuperClass<Swift.String>'. Relying on a particular conformance is undefined behaviour.
+// CHECK: Hello from main
+(GenericStruct<String>() as Any as! Hello).hello()
+
+assert(GenericStruct<Int>() as Any as? Hello == nil)
+
+class GenericSubClass<T>: GenericSuperClass<T> {}
+extension GenericSubClass: Hello where T == String {
+  func hello() {
+    print("Hello from main")
+  }
+}
+
+// CHECK: Hello from main
+(GenericSubClass<String>() as Any as! Hello).hello()
+
+// https://github.com/swiftlang/swift/issues/82889
+// CHECK: Expected nil
+// CHECK: Expected nil
+for _ in 0..<2 {
+  if GenericSubClass<Int>() as Any as? Hello != nil {
+    print("Unexpected successful cast")
+  } else {
+    print("Expected nil")
+  }
+}
diff --git a/test/remote-run/custom-options.test-sh b/test/remote-run/custom-options.test-sh
index 846005f1e0ba6..8bebe57af4427 100644
--- a/test/remote-run/custom-options.test-sh
+++ b/test/remote-run/custom-options.test-sh
@@ -1,3 +1,5 @@
+REQUIRES: rsync
+
 RUN: %remote-run -n --remote-dir /xyz-REMOTE -o FIRST_OPT -o SECOND_OPT --output-prefix %/t some_user@some_host:12345 cp %/t/nested/input %/t/nested/output 2>&1 >/dev/null | %FileCheck %s
 
 CHECK: /usr/bin/ssh -n
@@ -20,7 +22,7 @@ CHECK-SAME: 'cp'
 
 CHECK-NEXT: {{^}}/bin/mkdir -p {{.+}}
 
-CHECK-NEXT: /usr/bin/rsync
+CHECK-NEXT: rsync
 CHECK-DAG: '-p' '12345'
 CHECK-DAG: '-o' 'FIRST_OPT' '-o' 'SECOND_OPT'
 CHECK-SAME: some_user@some_host
diff --git a/test/remote-run/download.test-sh b/test/remote-run/download.test-sh
index 1cd5e1c75ce45..eec33d4306aa3 100644
--- a/test/remote-run/download.test-sh
+++ b/test/remote-run/download.test-sh
@@ -1,4 +1,4 @@
-REQUIRES: sftp_server
+REQUIRES: rsync
 
 RUN: %empty-directory(%t)
 RUN: %empty-directory(%t-REMOTE)
diff --git a/test/remote-run/dry-run-remote.test-sh b/test/remote-run/dry-run-remote.test-sh
index dcf18ad3b2edb..adf37419723f4 100644
--- a/test/remote-run/dry-run-remote.test-sh
+++ b/test/remote-run/dry-run-remote.test-sh
@@ -1,7 +1,9 @@
+REQUIRES: rsync
+
 RUN: %remote-run -n --remote-dir /xyz-REMOTE --input-prefix %S/Inputs/ some_user@some_host ls %S/Inputs/upload/1.txt %S/Inputs/upload/2.txt 2>&1 >/dev/null | %FileCheck -check-prefix CHECK-INPUT %s
 
 CHECK-INPUT: /usr/bin/ssh -n some_user@some_host -- '/usr/bin/env' '/bin/mkdir' '-p' '{{.+}}-REMOTE/input'
-CHECK-INPUT-NEXT: /usr/bin/rsync
+CHECK-INPUT-NEXT: rsync
 CHECK-INPUT-SAME: some_user@some_host
 
 CHECK-INPUT: /usr/bin/ssh -n some_user@some_host -- '/usr/bin/env' {{.*}}'ls'
@@ -12,11 +14,11 @@ RUN: touch %t/nested/input %t/nested/BAD
 RUN: %remote-run -n --remote-dir /xyz-REMOTE --output-prefix %/t some_user@some_host cp %/t/nested/input %/t/nested/output 2>&1 >/dev/null | %FileCheck -check-prefix CHECK-OUTPUT %s
 
 CHECK-OUTPUT: /usr/bin/ssh -n some_user@some_host -- '/usr/bin/env' '/bin/mkdir' '-p' '{{.+}}-REMOTE/output'
-CHECK-OUTPUT-NEXT: /usr/bin/rsync
+CHECK-OUTPUT-NEXT: rsync
 CHECK-OUTPUT-SAME: some_user@some_host
 
 CHECK-OUTPUT: /usr/bin/ssh -n some_user@some_host -- '/usr/bin/env' {{.*}}'cp'
 CHECK-OUTPUT-NEXT: {{^}}/bin/mkdir -p {{.+}}
-CHECK-OUTPUT-NEXT: /usr/bin/rsync
+CHECK-OUTPUT-NEXT: rsync
 CHECK-OUTPUT-SAME: some_user@some_host
 
diff --git a/test/remote-run/dry-run.test-sh b/test/remote-run/dry-run.test-sh
index dff156e2ffa35..05e949273c083 100644
--- a/test/remote-run/dry-run.test-sh
+++ b/test/remote-run/dry-run.test-sh
@@ -1,3 +1,4 @@
+REQUIRES: rsync
 REQUIRES: shell
 
 RUN: %empty-directory(%t)
@@ -6,7 +7,7 @@ RUN: test -z "`ls %t`"
 RUN: test ! -e %t-REMOTE
 
 CHECK-INPUT: /usr/bin/env /bin/mkdir -p {{.+}}-REMOTE/input
-CHECK-INPUT-NEXT: /usr/bin/rsync
+CHECK-INPUT-NEXT: rsync
 CHECK-INPUT: /usr/bin/env {{.*}}ls
 
 RUN: %empty-directory(%t)
@@ -16,8 +17,8 @@ RUN: %debug-remote-run -n --output-prefix %t cp %t/nested/input %t/nested/output
 RUN: test ! -e %t-REMOTE
 
 CHECK-OUTPUT: /usr/bin/env /bin/mkdir -p {{.+}}-REMOTE/output/nested
-CHECK-OUTPUT: /usr/bin/rsync
+CHECK-OUTPUT: rsync
 CHECK-OUTPUT: /usr/bin/env {{.*}}cp
 CHECK-OUTPUT-NEXT: {{^}}/bin/mkdir -p {{.+}}
-CHECK-OUTPUT-NEXT: /usr/bin/rsync
+CHECK-OUTPUT-NEXT: rsync
 
diff --git a/test/remote-run/env.test-sh b/test/remote-run/env.test-sh
index 580d54c7451ba..cf6f4648c9fdd 100644
--- a/test/remote-run/env.test-sh
+++ b/test/remote-run/env.test-sh
@@ -1,3 +1,4 @@
+REQUIRES: rsync
 REQUIRES: shell
 
 RUN: env REMOTE_RUN_CHILD_FOO=foo REMOTE_RUN_CHILD_BAR=bar %debug-remote-run sh -c 'echo ":${FOO}:" ":${BAR}:"' | %FileCheck %s
diff --git a/test/remote-run/exit-code.test-sh b/test/remote-run/exit-code.test-sh
index cd493e27cc38d..d69f7a91f2f97 100644
--- a/test/remote-run/exit-code.test-sh
+++ b/test/remote-run/exit-code.test-sh
@@ -1,3 +1,4 @@
+REQUIRES: rsync
 REQUIRES: shell
 
 RUN: export SWIFT_BACKTRACE=
diff --git a/test/remote-run/identity.test-sh b/test/remote-run/identity.test-sh
index e3377bcf01432..a68320c22e87d 100644
--- a/test/remote-run/identity.test-sh
+++ b/test/remote-run/identity.test-sh
@@ -1,3 +1,5 @@
+REQUIRES: rsync
+
 RUN: %remote-run -n --remote-dir /xyz-REMOTE -i spiderman --output-prefix %/t some_user@some_host:12345 cp %/t/nested/input %/t/nested/output 2>&1 >/dev/null | %FileCheck %s
 
 CHECK: /usr/bin/ssh -n
@@ -17,7 +19,7 @@ CHECK-SAME: some_user@some_host -- '/usr/bin/env' {{.*}}'cp'
 
 CHECK-NEXT: {{^}}/bin/mkdir -p {{.+}}
 
-CHECK-NEXT: /usr/bin/rsync
+CHECK-NEXT: rsync
 CHECK-DAG: '-p' '12345'
 CHECK-DAG: '-i' 'spiderman'
 CHECK-SAME: some_user@some_host
diff --git a/test/remote-run/port.test-sh b/test/remote-run/port.test-sh
index a34b1e5af5968..6f93a08e1325e 100644
--- a/test/remote-run/port.test-sh
+++ b/test/remote-run/port.test-sh
@@ -1,8 +1,10 @@
+REQUIRES: rsync
+
 RUN: %remote-run -n --remote-dir /xyz-REMOTE --output-prefix %/t some_user@some_host:12345 cp %/t/nested/input %/t/nested/output 2>&1 >/dev/null | %FileCheck %s
 
 CHECK: /usr/bin/ssh -n -p 12345 some_user@some_host -- '/usr/bin/env' '/bin/mkdir' '-p' '{{.+}}-REMOTE/output/nested'
 CHECK: /usr/bin/ssh -n -p 12345 some_user@some_host -- '/usr/bin/env' {{.*}}'cp'
 CHECK-NEXT: {{^}}/bin/mkdir -p {{.+}}
-CHECK-NEXT: /usr/bin/rsync
+CHECK-NEXT: rsync
 CHECK-SAME: '-p' '12345'
 CHECK-SAME: some_user@some_host
diff --git a/test/remote-run/run-only.test-sh b/test/remote-run/run-only.test-sh
index ab47c487b1b6f..ac51e1dcb4d0a 100644
--- a/test/remote-run/run-only.test-sh
+++ b/test/remote-run/run-only.test-sh
@@ -1,3 +1,4 @@
+REQUIRES: rsync
 REQUIRES: shell
 
 RUN: %debug-remote-run echo hello | %FileCheck %s
diff --git a/test/remote-run/stderr.test-sh b/test/remote-run/stderr.test-sh
index b37403c6c9b91..b0aadc3fbf850 100644
--- a/test/remote-run/stderr.test-sh
+++ b/test/remote-run/stderr.test-sh
@@ -1,3 +1,4 @@
+REQUIRES: rsync
 REQUIRES: shell
 
 RUN: %debug-remote-run sh -c "echo hello; echo goodbye >&2" > %t.stdout.txt 2> %t.stderr.txt
diff --git a/test/remote-run/upload-and-download.test-sh b/test/remote-run/upload-and-download.test-sh
index c82127e5a5b08..03b6395ab6938 100644
--- a/test/remote-run/upload-and-download.test-sh
+++ b/test/remote-run/upload-and-download.test-sh
@@ -1,4 +1,4 @@
-REQUIRES: sftp_server
+REQUIRES: rsync
 
 RUN: %empty-directory(%t)
 RUN: %empty-directory(%t-REMOTE)
@@ -27,10 +27,10 @@ RUN: ls %t-REMOTE/output/nested/ | %FileCheck -check-prefix CHECK-REMOTE %s
 RUN: %debug-remote-run -v --output-prefix %t cp %t/nested/input %t/nested/output 2>&1 >/dev/null | %FileCheck -check-prefix VERBOSE %s
 
 VERBOSE: /usr/bin/env /bin/mkdir -p {{.+}}-REMOTE/output/nested
-VERBOSE: /usr/bin/rsync
+VERBOSE: rsync
 VERBOSE: /usr/bin/env {{.*}}cp
 VERBOSE-NEXT: {{^}}/bin/mkdir -p {{.+}}
-VERBOSE-NEXT: /usr/bin/rsync
+VERBOSE-NEXT: rsync
 
 RUN: %empty-directory(%t)
 RUN: touch %t/xyz-1before
diff --git a/test/remote-run/upload-stderr.test-sh b/test/remote-run/upload-stderr.test-sh
index 1b36d1bf8795b..bb33cf9982102 100644
--- a/test/remote-run/upload-stderr.test-sh
+++ b/test/remote-run/upload-stderr.test-sh
@@ -1,4 +1,4 @@
-REQUIRES: sftp_server
+REQUIRES: rsync
 
 RUN: %empty-directory(%t)
 RUN: %empty-directory(%t/REMOTE/input)
diff --git a/test/remote-run/upload.test-sh b/test/remote-run/upload.test-sh
index ef505913babd7..31faa2247c021 100644
--- a/test/remote-run/upload.test-sh
+++ b/test/remote-run/upload.test-sh
@@ -1,4 +1,4 @@
-REQUIRES: sftp_server
+REQUIRES: rsync
 
 RUN: env REMOTE_RUN_CHILD_FOO=%S/Inputs/upload/3.txt %debug-remote-run --input-prefix %S/Inputs/upload/ ls %S/Inputs/upload/1.txt %S/Inputs/upload/2.txt | %FileCheck -check-prefix CHECK-REMOTE %s
 RUN: ls %t-REMOTE/input/ | %FileCheck %s
@@ -34,5 +34,5 @@ CHECK-NEXT: {{^3.txt$}}
 CHECK-NOT: BAD
 
 VERBOSE-NESTED: /usr/bin/env /bin/mkdir -p {{.+}}-REMOTE/input
-VERBOSE-NESTED-NEXT: /usr/bin/rsync
+VERBOSE-NESTED-NEXT: rsync
 VERBOSE-NESTED: /usr/bin/env {{.*}}ls
diff --git a/test/sil-func-extractor/load-serialized-sil.swift b/test/sil-func-extractor/load-serialized-sil.swift
index 49ee238d3a0a4..2233e8cc199c7 100644
--- a/test/sil-func-extractor/load-serialized-sil.swift
+++ b/test/sil-func-extractor/load-serialized-sil.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -module-link-name swiftCore -O -parse-as-library -parse-stdlib -emit-module -emit-module-path - -enable-ossa-modules -o /dev/null | %target-sil-func-extractor -module-name="Swift" -enable-ossa-modules -func='$ss1XV4testyyF' | %FileCheck %s
-// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -O -parse-as-library -parse-stdlib -emit-sib -enable-ossa-modules -o - | %target-sil-func-extractor -module-name="Swift" -enable-ossa-modules -func='$ss1XV4testyyF' | %FileCheck %s -check-prefix=SIB-CHECK
+// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -module-link-name swiftCore -O -parse-as-library -parse-stdlib -emit-module -emit-module-path - -o /dev/null | %target-sil-func-extractor -module-name="Swift" -func='$ss1XV4testyyF' | %FileCheck %s
+// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -O -parse-as-library -parse-stdlib -emit-sib -o - | %target-sil-func-extractor -module-name="Swift" -func='$ss1XV4testyyF' | %FileCheck %s -check-prefix=SIB-CHECK
 
 // CHECK: import Builtin
 // CHECK: import Swift
diff --git a/test/sil-llvm-gen/alloc.sil b/test/sil-llvm-gen/alloc.sil
index b39802a90cfea..385ee8ee9780c 100644
--- a/test/sil-llvm-gen/alloc.sil
+++ b/test/sil-llvm-gen/alloc.sil
@@ -1,12 +1,12 @@
-// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as -target x86_64-apple-macosx10.9 -module-name main %s -o - | %FileCheck %s
-// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as -target i386-apple-ios7.0 %s -module-name main -o - | %FileCheck %s
-// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as -target x86_64-apple-ios7.0 %s -module-name main -o - | %FileCheck %s
-// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as -target armv7-apple-ios7.0 %s -module-name main -o - | %FileCheck %s
-// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as -target arm64-apple-ios7.0 %s -module-name main -o - | %FileCheck %s
-// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as -target x86_64-unknown-linux-gnu %s -module-name main -o - | %FileCheck %s
+// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as-opt -target x86_64-apple-macosx10.9 -module-name main %s -o - | %FileCheck %s
+// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as-opt -target i386-apple-ios7.0 %s -module-name main -o - | %FileCheck %s
+// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as-opt -target x86_64-apple-ios7.0 %s -module-name main -o - | %FileCheck %s
+// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as-opt -target armv7-apple-ios7.0 %s -module-name main -o - | %FileCheck %s
+// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as-opt -target arm64-apple-ios7.0 %s -module-name main -o - | %FileCheck %s
+// RUN: %sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as-opt -target x86_64-unknown-linux-gnu %s -module-name main -o - | %FileCheck %s
 
 // Use this testfile to check if the `swift-frontend -sil-llvm-gen` option works.
-// RUN: %swift_frontend_plain -sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as -target x86_64-apple-macosx10.9 -module-name main %s -o - | %FileCheck %s
+// RUN: %swift_frontend_plain -sil-llvm-gen -disable-legacy-type-info -output-kind=llvm-as-opt -target x86_64-apple-macosx10.9 -module-name main %s -o - | %FileCheck %s
 
 // REQUIRES: CODEGENERATOR=X86
 // REQUIRES: CODEGENERATOR=ARM
diff --git a/test/sil-opt/sil-opt.swift b/test/sil-opt/sil-opt.swift
index ac51333f47c73..a51e9d32e62d9 100644
--- a/test/sil-opt/sil-opt.swift
+++ b/test/sil-opt/sil-opt.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -primary-file %s -enable-ossa-modules -module-name Swift -g -module-link-name swiftCore -O -parse-as-library -parse-stdlib -emit-module -emit-module-path - -o /dev/null | %target-sil-opt -enable-sil-verify-all -module-name="Swift" -emit-sorted-sil | %FileCheck %s
-// RUN: %target-swift-frontend -primary-file %s -enable-ossa-modules -module-name Swift -g -O -parse-as-library -parse-stdlib -emit-sib -o - | %target-sil-opt -enable-sil-verify-all -module-name="Swift" -emit-sorted-sil | %FileCheck %s -check-prefix=SIB-CHECK
+// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -module-link-name swiftCore -O -parse-as-library -parse-stdlib -emit-module -emit-module-path - -o /dev/null | %target-sil-opt -enable-sil-verify-all -module-name="Swift" -emit-sorted-sil | %FileCheck %s
+// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -O -parse-as-library -parse-stdlib -emit-sib -o - | %target-sil-opt -enable-sil-verify-all -module-name="Swift" -emit-sorted-sil | %FileCheck %s -check-prefix=SIB-CHECK
 
 // CHECK: import Builtin
 // CHECK: import Swift
diff --git a/test/stdlib/ArrayDiagnostics.swift b/test/stdlib/ArrayDiagnostics.swift
index f61451af26f48..011105bc400f7 100644
--- a/test/stdlib/ArrayDiagnostics.swift
+++ b/test/stdlib/ArrayDiagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 class NotEquatable {}
 
diff --git a/test/stdlib/BinaryIntegerRequirements.swift b/test/stdlib/BinaryIntegerRequirements.swift
index a4dc016950ed5..3dddb8c91459a 100644
--- a/test/stdlib/BinaryIntegerRequirements.swift
+++ b/test/stdlib/BinaryIntegerRequirements.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 4
 
 struct MyInt: FixedWidthInteger { // expected-error {{type 'MyInt' does not conform to protocol 'BinaryInteger'}} expected-note {{add stubs for conformance}}
   typealias IntegerLiteralType = Int
diff --git a/test/stdlib/BridgeEquatableToObjC.swift b/test/stdlib/BridgeEquatableToObjC.swift
index c426a0d6a55fb..b3649f8746fe8 100644
--- a/test/stdlib/BridgeEquatableToObjC.swift
+++ b/test/stdlib/BridgeEquatableToObjC.swift
@@ -22,6 +22,10 @@ struct MyNonEquatableStruct {
   var text: String
 }
 
+class MyEquatableClass: Equatable {
+  static func == (lhs: MyEquatableClass, rhs: MyEquatableClass) -> Bool { true }
+}
+
 BridgeEquatableToObjC.test("Bridge equatable struct") {
   let swiftA = MyEquatableStruct(text: "xABC")
   let swiftB = swiftA
@@ -46,5 +50,13 @@ BridgeEquatableToObjC.test("Bridge non-equatable struct") {
   expectEqual(objcResult, false)
 }
 
+BridgeEquatableToObjC.test("Compare tagged pointer to equatable SwiftObject") {
+  let literal = "The quick brown fox jumps over the lazy dog"
+  let bridgedLiteral = literal as NSString
+  let foo = MyEquatableClass()
+  let bridgedFoo = foo as AnyObject
+  let result = bridgedFoo.isEqual(bridgedLiteral)
+  expectEqual(result, false)
+}
 
 runAllTests()
diff --git a/test/stdlib/BridgedArrayNonContiguous.swift b/test/stdlib/BridgedArrayNonContiguous.swift
index 292de96dc8785..5de7141d4a797 100644
--- a/test/stdlib/BridgedArrayNonContiguous.swift
+++ b/test/stdlib/BridgedArrayNonContiguous.swift
@@ -10,11 +10,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-// RUN: %target-run-stdlib-swift -enable-experimental-feature LifetimeDependence
+// RUN: %target-run-stdlib-swift
 
 // REQUIRES: executable_test
 // REQUIRES: objc_interop
-// REQUIRES: swift_feature_LifetimeDependence
 
 import StdlibUnittest
 
@@ -24,6 +23,7 @@ var suite = TestSuite("EagerLazyBridgingTests")
 defer { runAllTests() }
 
 suite.test("Bridged NSArray without direct memory sharing") {
+  guard #available(SwiftStdlib 6.2, *) else { return }
 
   var arr = (0..<100).map({ _ in NSObject() as AnyObject})
   let identifiers = arr.map(ObjectIdentifier.init)
@@ -45,11 +45,7 @@ suite.test("Bridged NSArray without direct memory sharing") {
 }
 
 suite.test("Bridged NSArray as Span")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
+.require(.stdlib_6_2).code {
   guard #available(SwiftStdlib 6.2, *) else { return }
   
   var arr = (0..<100).map({ _ in NSObject() as AnyObject})
diff --git a/test/stdlib/CaseIterableTests.swift b/test/stdlib/CaseIterableTests.swift
index 687357938612e..15b864e5dcd07 100644
--- a/test/stdlib/CaseIterableTests.swift
+++ b/test/stdlib/CaseIterableTests.swift
@@ -17,7 +17,7 @@ CaseIterableTests.test("Simple Enums") {
   expectEqual(SimpleEnum.allCases, [.bar, .baz, .quux])
 }
 
-CaseIterableTests.test("MainActor Isolated Enums") {
+CaseIterableTests.test("MainActor-Isolated Enums") {
   @MainActor
   enum EnumMainActor: CaseIterable {
     case a, b
diff --git a/test/stdlib/CharacterTraps.swift b/test/stdlib/CharacterTraps.swift
index d7182ee2d9819..efa7f24fc59b9 100644
--- a/test/stdlib/CharacterTraps.swift
+++ b/test/stdlib/CharacterTraps.swift
@@ -7,7 +7,7 @@
 // RUN: %target-run %t/a.out_Debug
 // RUN: %target-run %t/a.out_Release
 // REQUIRES: executable_test
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 import StdlibUnittest
 
diff --git a/test/stdlib/DictionaryTraps.swift b/test/stdlib/DictionaryTraps.swift
index 07772984d6071..f177e5b533dd0 100644
--- a/test/stdlib/DictionaryTraps.swift
+++ b/test/stdlib/DictionaryTraps.swift
@@ -7,7 +7,7 @@
 // RUN: %target-run %t/a.out_Debug
 // RUN: %target-run %t/a.out_Release
 // REQUIRES: executable_test
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 import StdlibUnittest
 
diff --git a/test/stdlib/DispatchRenames.swift b/test/stdlib/DispatchRenames.swift
index d6d717a980409..047d5318c0138 100644
--- a/test/stdlib/DispatchRenames.swift
+++ b/test/stdlib/DispatchRenames.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift %import-libdispatch
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated %import-libdispatch
 // REQUIRES: libdispatch
 
 import Dispatch
diff --git a/test/stdlib/DispatchTypes.swift b/test/stdlib/DispatchTypes.swift
index 536bd8ef83faa..ca2e305791700 100644
--- a/test/stdlib/DispatchTypes.swift
+++ b/test/stdlib/DispatchTypes.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck %s
+// RUN: %target-swift-frontend -typecheck %s %import-libdispatch
 
 // REQUIRES: libdispatch
 // UNSUPPORTED: OS=linux-gnu
@@ -27,14 +27,22 @@ if #available(OSX 10.10, iOS 8.0, *) {
 // dispatch/source.h
 _ = DispatchSource.makeUserDataAddSource()
 _ = DispatchSource.makeUserDataOrSource()
+#if !os(FreeBSD)
 _ = DispatchSource.makeMachSendSource(port: mach_port_t(0), eventMask: [])
 _ = DispatchSource.makeMachReceiveSource(port: mach_port_t(0))
 _ = DispatchSource.makeMemoryPressureSource(eventMask: [])
+#endif
 _ = DispatchSource.makeProcessSource(identifier: 0, eventMask: [])
 _ = DispatchSource.makeReadSource(fileDescriptor: 0)
+#if os(FreeBSD)
+_ = DispatchSource.makeSignalSource(signal: 2)
+#else
 _ = DispatchSource.makeSignalSource(signal: SIGINT)
+#endif
 _ = DispatchSource.makeTimerSource()
+#if !os(FreeBSD)
 _ = DispatchSource.makeFileSystemObjectSource(fileDescriptor: 0, eventMask: [])
+#endif
 _ = DispatchSource.makeWriteSource(fileDescriptor: 0)
 
 // dispatch/time.h
diff --git a/test/stdlib/Duration.swift b/test/stdlib/Duration.swift
index 9e94003a63285..d6cdc5844acf1 100644
--- a/test/stdlib/Duration.swift
+++ b/test/stdlib/Duration.swift
@@ -28,11 +28,11 @@ if #available(SwiftStdlib 5.7, *) {
     // Divide by 1000 to get back to a duration with representable components:
     let smallerDuration = duration / 1000
     expectEqual(smallerDuration.components, (170_000_000_000_000_000, 0))
-    #if !os(WASI)
+#if !os(WASI)
     // Now check that the components of the original value trap:
     expectCrashLater()
     let _ = duration.components
-    #endif
+#endif
   }
   
   suite.test("milliseconds from Double") {
@@ -266,3 +266,14 @@ if #available(SwiftStdlib 6.0, *) {
     expectEqual(min.attoseconds, .min)
   }
 }
+
+if #available(SwiftStdlib 6.2, *) {
+  suite.test("nanoseconds from Double") {
+    for _ in 0 ..< 100 {
+      let integerValue = Double(Int64.random(in: 0 ... 0x7fff_ffff_ffff_fc00))
+      let (sec, attosec) = Duration.nanoseconds(integerValue).components
+      expectEqual(sec, Int64(integerValue) / 1_000_000_000)
+      expectEqual(attosec, Int64(integerValue) % 1_000_000_000 * 1_000_000_000)
+    }
+  }
+}
diff --git a/test/stdlib/FloatingPointDiagnostics.swift b/test/stdlib/FloatingPointDiagnostics.swift
index 54e3955c849dd..ef7cabb89ea78 100644
--- a/test/stdlib/FloatingPointDiagnostics.swift
+++ b/test/stdlib/FloatingPointDiagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 func unavailableModulo(description: String = "<rdar://problem/27855641>") {
   _ = 42.0 % 2 // expected-error {{For floating point numbers use truncatingRemainder}}
diff --git a/test/stdlib/FloatingPointIR_FP80.swift b/test/stdlib/FloatingPointIR_FP80.swift
index a5f0344ec054e..318d7010b5159 100644
--- a/test/stdlib/FloatingPointIR_FP80.swift
+++ b/test/stdlib/FloatingPointIR_FP80.swift
@@ -3,7 +3,9 @@
 // RUN: %target-build-swift -Ounchecked -emit-ir %s | %FileCheck -check-prefix=%target-cpu %s
 
 // REQUIRES: CPU=i386 || CPU=x86_64
-// UNSUPPORTED: OS=windows-msvc
+//
+// Windows and Android do not expose Float80.
+// UNSUPPORTED: OS=windows-msvc, OS=linux-android
 
 var globalFloat80 : Float80 = 0.0
 
diff --git a/test/stdlib/InlineArray.swift b/test/stdlib/InlineArray.swift
index ae9037dc2dd01..1892ba7de4d53 100644
--- a/test/stdlib/InlineArray.swift
+++ b/test/stdlib/InlineArray.swift
@@ -24,6 +24,8 @@
 import StdlibUnittest
 import Synchronization
 
+protocol P {}
+
 @available(SwiftStdlib 6.2, *)
 @main
 enum InlineArrayTests {
@@ -166,11 +168,14 @@ enum InlineArrayTests {
     let error = CancellationError()
     do {
       expectDoesNotThrow {
-        let a = try InlineArray<0, String> { _ in throw error }
+        let a = try InlineArray<0, String>({ _ in throw error })
         _checkInlineArray(a, oracle: [])
       }
       _expectThrows {
-        let _ = try InlineArray<1, String> { _ in throw error }
+        let _ = try InlineArray<1, String>({ _ in throw error })
+      }
+      _expectThrows {
+        let _ = try InlineArray<1, any P>({ _ in throw error })
       }
       _expectThrows {
         let _ = try InlineArray<2, String> { index in
diff --git a/test/stdlib/InputStream.swift.gyb b/test/stdlib/InputStream.swift.gyb
index ded862181457f..b5b3ae2a50c85 100644
--- a/test/stdlib/InputStream.swift.gyb
+++ b/test/stdlib/InputStream.swift.gyb
@@ -13,7 +13,7 @@
 // RUN: %target-run-simple-swiftgyb
 // REQUIRES: executable_test
 // UNSUPPORTED: freestanding
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 import StdlibUnittest
 
diff --git a/test/stdlib/IntegerDiagnostics.swift b/test/stdlib/IntegerDiagnostics.swift
index cdb0cd4e345f9..f8222c52d9f5b 100644
--- a/test/stdlib/IntegerDiagnostics.swift
+++ b/test/stdlib/IntegerDiagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 4
 
 func signedBitPattern() {
   _ = Int64(bitPattern: 0.0) // expected-error {{Please use Int64(bitPattern: UInt64) in combination with Double.bitPattern property.}}
diff --git a/test/stdlib/IntervalTraps.swift b/test/stdlib/IntervalTraps.swift
index c6105d03ddba5..e8add3e663dbd 100644
--- a/test/stdlib/IntervalTraps.swift
+++ b/test/stdlib/IntervalTraps.swift
@@ -18,7 +18,7 @@
 // RUN: %target-run %t/a.out_Debug
 // RUN: %target-run %t/a.out_Release
 // REQUIRES: executable_test
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 import StdlibUnittest
 
diff --git a/test/stdlib/KeyPath.swift b/test/stdlib/KeyPath.swift
index fb3b0c1e5510c..5da22242f33b7 100644
--- a/test/stdlib/KeyPath.swift
+++ b/test/stdlib/KeyPath.swift
@@ -1159,5 +1159,117 @@ if #available(SwiftStdlib 5.9, *) {
   }
 }
 
+@_alignment(8)
+struct EightAligned {
+  let x = 0
+}
+
+extension EightAligned: Equatable {}
+extension EightAligned: Hashable {}
+
+@_alignment(16)
+struct SixteenAligned {
+  let x = 0
+}
+
+extension SixteenAligned: Equatable {}
+extension SixteenAligned: Hashable {}
+
+struct OveralignedForEight {
+  subscript(getter getter: EightAligned) -> Int {
+    128
+  }
+
+  subscript(setter setter: EightAligned) -> Int {
+    get {
+      128
+    }
+
+    set {
+      fatalError()
+    }
+  }
+}
+
+struct OveralignedForSixteen {
+  subscript(getter getter: SixteenAligned) -> Int {
+    128
+  }
+
+  subscript(setter setter: SixteenAligned) -> Int {
+    get {
+      128
+    }
+
+    set {
+      fatalError()
+    }
+  }
+}
+
+struct SimpleEight {
+  let oa = OveralignedForEight()
+}
+
+struct SimpleSixteen {
+  let oa = OveralignedForSixteen()
+}
+
+#if _pointerBitWidth(_32)
+if #available(SwiftStdlib 6.3, *) {
+  keyPath.test("eight byte overaligned arguments") {
+    let oa = OveralignedForEight()
+    let kp = \OveralignedForEight.[getter: EightAligned()]
+
+    let value = oa[keyPath: kp]
+    expectEqual(value, 128)
+
+    // Test that appends where the argument is no longer overaligned work
+    let simple = SimpleEight()
+    let kp11 = \SimpleEight.oa
+    let kp12 = \OveralignedForEight.[getter: EightAligned()]
+    let kp1 = kp11.appending(path: kp12)
+
+    let value1 = simple[keyPath: kp1]
+    expectEqual(value1, 128)
+
+    // Test that appends where the argument is still overaligned works
+    let kp21 = \SimpleEight.oa
+    let kp22 = \OveralignedForEight.[setter: EightAligned()]
+    let kp2 = kp21.appending(path: kp22)
+
+    let value2 = simple[keyPath: kp2]
+    expectEqual(value2, 128)
+  }
+}
+#endif
+
+if #available(SwiftStdlib 6.3, *) {
+  keyPath.test("sixteen byte overaligned arguments") {
+    let oa = OveralignedForSixteen()
+    let kp = \OveralignedForSixteen.[getter: SixteenAligned()]
+
+    let value = oa[keyPath: kp]
+    expectEqual(value, 128)
+
+    // Test that appends where the argument is no longer overaligned work
+    let simple = SimpleSixteen()
+    let kp11 = \SimpleSixteen.oa
+    let kp12 = \OveralignedForSixteen.[getter: SixteenAligned()]
+    let kp1 = kp11.appending(path: kp12)
+
+    let value1 = simple[keyPath: kp1]
+    expectEqual(value1, 128)
+
+    // Test that appends where the argument is still overaligned works
+    let kp21 = \SimpleSixteen.oa
+    let kp22 = \OveralignedForSixteen.[setter: SixteenAligned()]
+    let kp2 = kp21.appending(path: kp22)
+
+    let value2 = simple[keyPath: kp2]
+    expectEqual(value2, 128)
+  }
+}
+
 runAllTests()
 
diff --git a/test/stdlib/KeyPathAppending.swift b/test/stdlib/KeyPathAppending.swift
index 0e94e527474bc..9eb438079f515 100644
--- a/test/stdlib/KeyPathAppending.swift
+++ b/test/stdlib/KeyPathAppending.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // Check that all combinations of key paths produce the expected result type
 // and choose the expected overloads.
diff --git a/test/stdlib/OSLogExecutionTest.swift b/test/stdlib/OSLogExecutionTest.swift
index 3fe204ccaf9ed..827f07d401f3b 100644
--- a/test/stdlib/OSLogExecutionTest.swift
+++ b/test/stdlib/OSLogExecutionTest.swift
@@ -10,6 +10,8 @@
 // REQUIRES: foundation
 //
 // REQUIRES: VENDOR=apple
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
 
 // Run-time tests for testing the correctness of the optimizations that optimize the
 // construction of the format string and the byte buffer from a string interpolation.
diff --git a/test/stdlib/OptionalGeneralizations.swift b/test/stdlib/OptionalGeneralizations.swift
index d06dcff2174e6..a8b6a0089b14c 100644
--- a/test/stdlib/OptionalGeneralizations.swift
+++ b/test/stdlib/OptionalGeneralizations.swift
@@ -1,8 +1,7 @@
-// RUN: %target-run-simple-swift(-enable-experimental-feature NonescapableTypes -enable-experimental-feature LifetimeDependence)
+// RUN: %target-run-simple-swift(-enable-experimental-feature Lifetimes)
 // REQUIRES: executable_test
 // REQUIRES: reflection
-// REQUIRES: swift_feature_NonescapableTypes
-// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: swift_feature_Lifetimes
 
 import StdlibUnittest
 import Swift
@@ -17,46 +16,37 @@ func isCopyable<T: ~Escapable>(_: T.Type) -> Bool { true }
 func isBitwiseCopyable<T: ~Copyable & ~Escapable>(_: T.Type) -> Bool { false }
 func isBitwiseCopyable<T: BitwiseCopyable & ~Escapable>(_: T.Type) -> Bool { true }
 
-#if $NonescapableTypes
 func isEscapable<T: ~Escapable & ~Copyable>(_: T.Type) -> Bool { false }
 func isEscapable<T: ~Copyable>(_: T.Type) -> Bool { true }
-#endif
 
 struct TrivialStruct {}
 struct NoncopyableStruct: ~Copyable {}
 class RegularClass {}
 
-#if $NonescapableTypes
 struct NonescapableStruct: ~Escapable, BitwiseCopyable {}
 struct NoncopyableNonescapableStruct: ~Copyable, ~Escapable {}
 struct NonescapableNontrivialStruct: ~Escapable {
   let foo: RegularClass? = nil
 }
-#endif
 
 suite.test("Copyability") {
   expectTrue(isCopyable(Optional<TrivialStruct>.self))
   expectFalse(isCopyable(Optional<NoncopyableStruct>.self))
   expectTrue(isCopyable(Optional<RegularClass>.self))
-#if $NonescapableTypes
   expectTrue(isCopyable(Optional<NonescapableStruct>.self))
   expectFalse(isCopyable(Optional<NoncopyableNonescapableStruct>.self))
   expectTrue(isCopyable(Optional<NonescapableNontrivialStruct>.self))
-#endif
 }
 
 suite.test("BitwiseCopyability") {
   expectTrue(isBitwiseCopyable(Optional<TrivialStruct>.self))
   expectFalse(isBitwiseCopyable(Optional<NoncopyableStruct>.self))
   expectFalse(isBitwiseCopyable(Optional<RegularClass>.self))
-#if $NonescapableTypes
   expectTrue(isBitwiseCopyable(Optional<NonescapableStruct>.self))
   expectFalse(isBitwiseCopyable(Optional<NoncopyableNonescapableStruct>.self))
   expectFalse(isBitwiseCopyable(Optional<NonescapableNontrivialStruct>.self))
-#endif
 }
 
-#if $NonescapableTypes
 suite.test("Escapability") {
   expectTrue(isEscapable(Optional<TrivialStruct>.self))
   expectTrue(isEscapable(Optional<NoncopyableStruct>.self))
@@ -65,7 +55,6 @@ suite.test("Escapability") {
   expectFalse(isEscapable(Optional<NoncopyableNonescapableStruct>.self))
   expectFalse(isEscapable(Optional<NonescapableNontrivialStruct>.self))
 }
-#endif
 
 func apply<T, U>(
   _ input: T,
@@ -92,3 +81,39 @@ suite.test("Initializer references") {
     expectTrue(r != nil)
   }
 }
+
+suite.test("expectNotNil()") {
+  func opt1<T: ~Copyable>(_ t: consuming T) -> T? { Optional.some(t) }
+  _ = expectNotNil(opt1(TrivialStruct()))
+  _ = expectNotNil(opt1(NoncopyableStruct()))
+  _ = expectNotNil(opt1(RegularClass()))
+  @_lifetime(copy t)
+  func opt2<T: ~Copyable & ~Escapable>(_ t: consuming T) -> T? { t }
+
+  let ne = NonescapableStruct()
+  _ = expectNotNil(opt2(ne))
+
+  let ncne = NoncopyableNonescapableStruct()
+  _ = expectNotNil(opt2(ncne))
+
+  let nent = NonescapableNontrivialStruct()
+  _ = expectNotNil(opt2(nent))
+}
+
+suite.test("expectNil()") {
+  func opt1<T: ~Copyable>(_ t: consuming T) -> T? { nil }
+  expectNil(opt1(TrivialStruct()))
+  expectNil(opt1(NoncopyableStruct()))
+  expectNil(opt1(RegularClass()))
+  @_lifetime(copy t)
+  func opt2<T: ~Copyable & ~Escapable>(_ t: consuming T) -> T? { nil }
+
+  let ne = NonescapableStruct()
+  expectNil(opt2(ne))
+
+  let ncne = NoncopyableNonescapableStruct()
+  expectNil(opt2(ncne))
+
+  let nent = NonescapableNontrivialStruct()
+  expectNil(opt2(nent))
+}
diff --git a/test/stdlib/OptionalTraps.swift b/test/stdlib/OptionalTraps.swift
index e4de3c4cee957..8c678345b76da 100644
--- a/test/stdlib/OptionalTraps.swift
+++ b/test/stdlib/OptionalTraps.swift
@@ -10,7 +10,7 @@
 // RUN: %target-run %t/Assert_Release
 // RUN: %target-run %t/Assert_Unchecked
 // REQUIRES: executable_test
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 import StdlibUnittest
 
@@ -77,7 +77,7 @@ OptionalTraps.test("UnwrapNone/Message")
     reason: "this trap may not have an error message may not be printed in -O"))
   .code {
   var a: AnyObject? = returnNil()
-  expectCrashLater(withMessage: 
+  expectCrashLater(withMessage:
       "Unexpectedly found nil while unwrapping an Optional value")
   let unwrapped: AnyObject = a!
   _blackHole(unwrapped)
@@ -92,7 +92,7 @@ OptionalTraps.test("UnwrapNone/Message/Implicit")
     reason: "this trap may not have an error message may not be printed in -O"))
   .code {
   var a: AnyObject! = returnNil()
-  expectCrashLater(withMessage: 
+  expectCrashLater(withMessage:
       "Unexpectedly found nil while implicitly unwrapping an Optional value")
   let unwrapped: AnyObject = a
   _blackHole(unwrapped)
diff --git a/test/stdlib/POSIX.swift b/test/stdlib/POSIX.swift
index 42b9edb5f4123..5999b3435091e 100644
--- a/test/stdlib/POSIX.swift
+++ b/test/stdlib/POSIX.swift
@@ -1,7 +1,8 @@
 // RUN: %target-run-simple-swift %t
 // REQUIRES: executable_test
 // UNSUPPORTED: OS=windows-msvc
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
+// UNSUPPORTED: OS=freebsd
 
 import StdlibUnittest
 import SwiftPrivateLibcExtras
diff --git a/test/stdlib/PrintFloat.swift.gyb b/test/stdlib/PrintFloat.swift.gyb
index 5377a6d2b2467..c14324cf6cd99 100644
--- a/test/stdlib/PrintFloat.swift.gyb
+++ b/test/stdlib/PrintFloat.swift.gyb
@@ -13,7 +13,9 @@
 
 import StdlibUnittest
 import SwiftPrivateLibcExtras
-#if canImport(Darwin)
+#if canImport(locale_h)
+  import locale_h
+#elseif canImport(Darwin)
   import Darwin
 #elseif canImport(Glibc)
   import Glibc
diff --git a/test/stdlib/PrintString.swift b/test/stdlib/PrintString.swift
index 45bfb946c10fd..58000c93fecd1 100644
--- a/test/stdlib/PrintString.swift
+++ b/test/stdlib/PrintString.swift
@@ -92,6 +92,11 @@ PrintTests.test("StringInterpolation") {
   
   let s2 = "aaa\(1)bbb\(2 as Any)"
   expectEqual("aaa1bbb2", s2)
+  
+  let x: Int? = 1
+  let y: Int? = nil
+  let s3 = "aaa\(x, default: "NONE")bbb\(y, default: "NONE")"
+  expectEqual("aaa1bbbNONE", s3)
 }
 
 PrintTests.test("SubstringInterpolation") {
@@ -100,6 +105,11 @@ PrintTests.test("SubstringInterpolation") {
   
   let s2 = "aaa\(1)bbb\(2 as Any)" as Substring
   expectEqual("aaa1bbb2", s2)
+  
+  let x: Int? = 1
+  let y: Int? = nil
+  let s3 = "aaa\(x, default: "NONE")bbb\(y, default: "NONE")" as Substring
+  expectEqual("aaa1bbbNONE", s3)
 }
 
 PrintTests.test("CustomStringInterpolation") {
@@ -116,6 +126,11 @@ PrintTests.test("AutoCustomStringInterpolation") {
   
   let s2 = ("aaa\(1)bbb\(2 as Any)" as MySimpleString).value
   expectEqual("aaa1bbb2", s2)
+  
+  let x: Int? = 1
+  let y: Int? = nil
+  let s3 = ("aaa\(x, default: "NONE")bbb\(y, default: "NONE")" as MySimpleString).value
+  expectEqual("aaa1bbbNONE", s3)
 }
 
 PrintTests.test("CustomStringInterpolationExtra") {
diff --git a/test/stdlib/Random.swift b/test/stdlib/Random.swift
index 8a8c2258d4320..6ad63f2edcb52 100644
--- a/test/stdlib/Random.swift
+++ b/test/stdlib/Random.swift
@@ -9,7 +9,7 @@
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 struct Jawn { }
 
diff --git a/test/stdlib/RangeContainsInlining.swift b/test/stdlib/RangeContainsInlining.swift
new file mode 100644
index 0000000000000..0b3892f7a4f72
--- /dev/null
+++ b/test/stdlib/RangeContainsInlining.swift
@@ -0,0 +1,43 @@
+// RUN: %target-swift-emit-ir -primary-file %s 2>&1 | %FileCheck %s
+// RUN: %target-swift-emit-ir -primary-file %s -O 2>&1 | %FileCheck --check-prefixes CHECK,CHECK-OPTIMIZED %s
+// RUN: %target-swift-emit-ir -primary-file %s -Osize 2>&1 | %FileCheck --check-prefixes CHECK,CHECK-OPTIMIZED %s
+
+// We expect calls to `Range.contains` to result in direct bound comparisons in
+// all compilation modes, including unoptimized builds. (These are often used to
+// implement bounds checking.)
+//
+// The sample functions below use bounds of different integer types to avoid
+// them tail-calling each other.
+
+// CHECK-LABEL: define {{.*}} i1 @"$s21RangeContainsInlining08halfOpenB0ySbSnys4Int8VG_ADtF"
+// CHECK-NOT: call swiftcc
+// CHECK: icmp
+// CHECK-NOT: call swiftcc
+// CHECK-LABEL: {{^}}}
+public func halfOpenContains(_ r: Range<Int8>, _ i: Int8) -> Bool {
+  r.contains(i)
+}
+
+// `ClosedRange.contains is only marked `@inline(__always)`; unfortunately it
+// doesn't get inlined in deug builds.
+
+// CHECK-OPTIMIZED-LABEL: define  {{.*}} i1 @"$s21RangeContainsInlining06closedB0ySbSNys5Int16VG_ADtF"
+// CHECK-OPTIMIZED-NOT: call swiftcc
+// CHECK-OPTIMIZED: icmp
+// CHECK-OPTIMIZED-NOT: call swiftcc
+// CHECK-OPTIMIZED-LABEL: {{^}}}
+public func closedContains(_ r: ClosedRange<Int16>, _ i: Int16) -> Bool {
+  r.contains(i)
+}
+
+// `Range.~=` is only marked `@inline(__always)`; unfortunately it doesn't get
+// inlined in deug builds.
+
+// CHECK-OPTIMIZED-LABEL: define {{.*}} i1 @"$s21RangeContainsInlining20halfOpenPatternMatchySbSnys5Int32VG_ADtF"
+// CHECK-OPTIMIZED-NOT: call swiftcc
+// CHECK-OPTIMIZED: icmp
+// CHECK-OPTIMIZED-NOT: call swiftcc
+// CHECK-OPTIMIZED-LABEL: {{^}}}
+public func halfOpenPatternMatch(_ r: Range<Int32>, _ i: Int32) -> Bool {
+  r ~= i
+}
diff --git a/test/stdlib/RangeTraps.swift b/test/stdlib/RangeTraps.swift
index 3954079e8ef7c..e252e18bb7eec 100644
--- a/test/stdlib/RangeTraps.swift
+++ b/test/stdlib/RangeTraps.swift
@@ -18,7 +18,7 @@
 // RUN: %target-run %t/a.out_Debug
 // RUN: %target-run %t/a.out_Release
 // REQUIRES: executable_test
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 
 import StdlibUnittest
@@ -34,7 +34,7 @@ RangeTraps.test("HalfOpen")
   .code {
   var range = 1..<1
   expectType(CountableRange<Int>.self, &range)
-  
+
   expectCrashLater()
   _ = 1..<0
 }
@@ -67,7 +67,7 @@ RangeTraps.test("CountablePartialRangeFrom")
     { _isFastAssertConfiguration() },
     reason: "this trap is not guaranteed to happen in -Ounchecked"))
   .code {
-    
+
     let range = (Int.max - 1)...
     var it = range.makeIterator()
     _ = it.next()
diff --git a/test/stdlib/SIMDFloatComparisons.swift.gyb b/test/stdlib/SIMDFloatComparisons.swift.gyb
new file mode 100644
index 0000000000000..38e1e9d85de6c
--- /dev/null
+++ b/test/stdlib/SIMDFloatComparisons.swift.gyb
@@ -0,0 +1,134 @@
+//===--- SIMDFloatComparisons.swift.gyb -----------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+// RUN: %empty-directory(%t)
+// RUN: %gyb %s -o %t/SIMDFloatComparisons.swift
+// RUN: %target-swift-frontend -primary-file %t/SIMDFloatComparisons.swift -emit-ir | %FileCheck %t/SIMDFloatComparisons.swift --check-prefix=CHECK --check-prefix=CHECK-%target-cpu
+
+import Swift
+
+%for bits in [16,32,64]:
+% scalar = {16:'Float16',32:'Float',64:'Double'}[bits]
+% llvm = {16:'half',32:'float',64:'double'}[bits]
+% for totalBits in [64,128]:
+%  if bits == 16 or totalBits == 64:
+%   arch = "-arm64"
+%  else:
+%   arch = ""
+%  end
+%  n = totalBits // bits
+%  if n != 1:
+%   neonSuffix = str(n) + {8:'b',16:'h',32:'s',64:'d'}[bits]
+%   if bits == 16:
+#if arch(arm64)
+@available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
+%   end
+func compare_eq${n}x${bits}(
+  _ a: SIMD${n}<${scalar}>, _ b: SIMD${n}<${scalar}>
+) -> SIMDMask<SIMD${n}<Int${bits}>> {
+  a .== b
+}
+%   if bits == 16:
+#endif
+%   end
+// CHECK${arch}: compare_eq${n}x${bits}{{.*}} {
+// CHECK${arch}: entry:
+// CHECK${arch}: [[TMP:%[0-9]+]] = fcmp oeq <${n} x ${llvm}> %0, %1
+// CHECK${arch}-NEXT: sext <${n} x i1> [[TMP]] to <${n} x i${bits}>
+
+%   if bits == 16:
+#if arch(arm64)
+@available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
+%   end
+func compare_ne${n}x${bits}(
+  _ a: SIMD${n}<${scalar}>, _ b: SIMD${n}<${scalar}>
+) -> SIMDMask<SIMD${n}<Int${bits}>> {
+  a .!= b
+}
+%   if bits == 16:
+#endif
+%   end
+// CHECK${arch}: compare_ne${n}x${bits}{{.*}} {
+// CHECK${arch}: entry:
+// CHECK${arch}: [[TMP:%[0-9]+]] = fcmp une <${n} x ${llvm}> %0, %1
+// CHECK${arch}-NEXT: sext <${n} x i1> [[TMP]] to <${n} x i${bits}>
+
+%   if bits == 16:
+#if arch(arm64)
+@available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
+%   end
+func compare_lt${n}x${bits}(
+  _ a: SIMD${n}<${scalar}>, _ b: SIMD${n}<${scalar}>
+) -> SIMDMask<SIMD${n}<Int${bits}>> {
+  a .< b
+}
+%   if bits == 16:
+#endif
+%   end
+// CHECK${arch}: compare_lt${n}x${bits}{{.*}} {
+// CHECK${arch}: entry:
+// CHECK${arch}: [[TMP:%[0-9]+]] = fcmp olt <${n} x ${llvm}> %0, %1
+// CHECK${arch}-NEXT: sext <${n} x i1> [[TMP]] to <${n} x i${bits}>
+
+%   if bits == 16:
+#if arch(arm64)
+@available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
+%   end
+func compare_le${n}x${bits}(
+  _ a: SIMD${n}<${scalar}>, _ b: SIMD${n}<${scalar}>
+) -> SIMDMask<SIMD${n}<Int${bits}>> {
+  a .<= b
+}
+%   if bits == 16:
+#endif
+%   end
+// CHECK${arch}: compare_le${n}x${bits}{{.*}} {
+// CHECK${arch}: entry:
+// CHECK${arch}: [[TMP:%[0-9]+]] = fcmp ole <${n} x ${llvm}> %0, %1
+// CHECK${arch}-NEXT: sext <${n} x i1> [[TMP]] to <${n} x i${bits}>
+
+%   if bits == 16:
+#if arch(arm64)
+@available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
+%   end
+func compare_ge${n}x${bits}(
+  _ a: SIMD${n}<${scalar}>, _ b: SIMD${n}<${scalar}>
+) -> SIMDMask<SIMD${n}<Int${bits}>> {
+  a .>= b
+}
+%   if bits == 16:
+#endif
+%   end
+// CHECK${arch}: compare_ge${n}x${bits}{{.*}} {
+// CHECK${arch}: entry:
+// CHECK${arch}: [[TMP:%[0-9]+]] = fcmp oge <${n} x ${llvm}> %0, %1
+// CHECK${arch}-NEXT: sext <${n} x i1> [[TMP]] to <${n} x i${bits}>
+
+%   if bits == 16:
+#if arch(arm64)
+@available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
+%   end
+func compare_gt${n}x${bits}(
+  _ a: SIMD${n}<${scalar}>, _ b: SIMD${n}<${scalar}>
+) -> SIMDMask<SIMD${n}<Int${bits}>> {
+  a .> b
+}
+%   if bits == 16:
+#endif
+%   end
+// CHECK${arch}: compare_gt${n}x${bits}{{.*}} {
+// CHECK${arch}: entry:
+// CHECK${arch}: [[TMP:%[0-9]+]] = fcmp ogt <${n} x ${llvm}> %0, %1
+// CHECK${arch}-NEXT: sext <${n} x i1> [[TMP]] to <${n} x i${bits}>
+
+%  end
+% end
+%end
diff --git a/test/stdlib/SIMDFloatInitializers.swift.gyb b/test/stdlib/SIMDFloatInitializers.swift.gyb
new file mode 100644
index 0000000000000..43e8e7f49ca68
--- /dev/null
+++ b/test/stdlib/SIMDFloatInitializers.swift.gyb
@@ -0,0 +1,47 @@
+//===--- SIMDFloatInitializers.swift.gyb -------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+// RUN: %empty-directory(%t)
+// RUN: %gyb %s -o %t/SIMDFloatInitializers.swift
+// RUN: %target-swift-frontend -primary-file %t/SIMDFloatInitializers.swift -emit-ir | %FileCheck %t/SIMDFloatInitializers.swift --check-prefix=CHECK --check-prefix=CHECK-%target-cpu
+
+import Swift
+
+%for bits in [16,32,64]:
+% if bits == 16:
+%  arch = "-arm64"
+% else:
+%  arch = ""
+% end
+% scalar = {16:'Float16',32:'Float',64:'Double'}[bits]
+% llvm = {16:'half',32:'float',64:'double'}[bits]
+% for totalBits in [64,128]:
+%  n = totalBits // bits
+%  if n != 1:
+%   neonSuffix = str(n) + {8:'b',16:'h',32:'s',64:'d'}[bits]
+%   if bits == 16:
+#if arch(arm64)
+@available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
+%   end
+func repeating${n}x${bits}(_ scalar: ${scalar}) -> SIMD${n}<${scalar}> {
+  SIMD${n}(repeating: scalar)
+}
+%   if bits == 16:
+#endif
+%   end
+// CHECK${arch}: repeating${n}x${bits}{{.*}} {
+// CHECK${arch}: entry:
+// CHECK${arch}: [[TMP:%[0-9]+]] = insertelement <${n} x ${llvm}> {{.*}} ${llvm} %0, i32 0
+// CHECK${arch}-NEXT: [[REP:%[0-9]+]] = shufflevector <${n} x ${llvm}> [[TMP]], <${n} x ${llvm}> {{.*}}, <${n} x i32> zeroinitializer
+
+%  end
+% end
+%end
diff --git a/test/stdlib/SIMDMaskInitializers.swift.gyb b/test/stdlib/SIMDMaskInitializers.swift.gyb
new file mode 100644
index 0000000000000..3bbc83d5e817f
--- /dev/null
+++ b/test/stdlib/SIMDMaskInitializers.swift.gyb
@@ -0,0 +1,33 @@
+//===--- SIMDMaskInitializers.swift.gyb -------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+// RUN: %empty-directory(%t)
+// RUN: %gyb %s -o %t/SIMDMaskInitializers.swift
+// RUN: %target-swift-frontend -primary-file %t/SIMDMaskInitializers.swift -emit-ir | %FileCheck %t/SIMDMaskInitializers.swift --check-prefix=CHECK --check-prefix=CHECK-%target-cpu
+
+import Swift
+
+%for bits in [8,16,32,64]:
+% for totalBits in [64,128]:
+%  n = totalBits // bits
+%  if n != 1:
+%   neonSuffix = str(n) + {8:'b',16:'h',32:'s',64:'d'}[bits]
+func repeating${n}_mask${bits}(_ scalar: Bool) -> SIMDMask<SIMD${n}<Int${bits}>> {
+  SIMDMask(repeating: scalar)
+}
+// CHECK: repeating${n}_mask${bits}{{.*}} {
+// CHECK: entry:
+// CHECK: [[TMP:%[0-9]+]] = insertelement <${n} x i${bits}> {{.*}}, i${bits} %{{.*}}, i32 0
+// CHECK-NEXT: [[REP:%[0-9]+]] = shufflevector <${n} x i${bits}> [[TMP]], <${n} x i${bits}> {{.*}}, <${n} x i32> zeroinitializer
+
+%  end
+% end
+%end
diff --git a/test/stdlib/SIMDSignedInitializers.swift.gyb b/test/stdlib/SIMDSignedInitializers.swift.gyb
new file mode 100644
index 0000000000000..82e2b3471396b
--- /dev/null
+++ b/test/stdlib/SIMDSignedInitializers.swift.gyb
@@ -0,0 +1,33 @@
+//===--- SIMDSignedInitializers.swift.gyb ---------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+// RUN: %empty-directory(%t)
+// RUN: %gyb %s -o %t/SIMDSignedInitializers.swift
+// RUN: %target-swift-frontend -primary-file %t/SIMDSignedInitializers.swift -emit-ir | %FileCheck %t/SIMDSignedInitializers.swift --check-prefix=CHECK --check-prefix=CHECK-%target-cpu
+
+import Swift
+
+%for bits in [8,16,32,64]:
+% for totalBits in [64,128]:
+%  n = totalBits // bits
+%  if n != 1:
+%   neonSuffix = str(n) + {8:'b',16:'h',32:'s',64:'d'}[bits]
+func repeating${n}_int${bits}(_ scalar: Int${bits}) -> SIMD${n}<Int${bits}> {
+  SIMD${n}(repeating: scalar)
+}
+// CHECK: repeating${n}_int${bits}{{.*}} {
+// CHECK: entry:
+// CHECK: [[TMP:%[0-9]+]] = insertelement <${n} x i${bits}> {{.*}}, i${bits} %0, i32 0
+// CHECK-NEXT: [[REP:%[0-9]+]] = shufflevector <${n} x i${bits}> [[TMP]], <${n} x i${bits}> {{.*}}, <${n} x i32> zeroinitializer
+
+%  end
+% end
+%end
diff --git a/test/stdlib/SIMDUnsignedInitializers.swift.gyb b/test/stdlib/SIMDUnsignedInitializers.swift.gyb
new file mode 100644
index 0000000000000..b4d3fd3c6c2ef
--- /dev/null
+++ b/test/stdlib/SIMDUnsignedInitializers.swift.gyb
@@ -0,0 +1,33 @@
+//===--- SIMDUnsignedInitializers.swift.gyb -------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+// RUN: %empty-directory(%t)
+// RUN: %gyb %s -o %t/SIMDUnsignedInitializers.swift
+// RUN: %target-swift-frontend -primary-file %t/SIMDUnsignedInitializers.swift -emit-ir | %FileCheck %t/SIMDUnsignedInitializers.swift --check-prefix=CHECK --check-prefix=CHECK-%target-cpu
+
+import Swift
+
+%for bits in [8,16,32,64]:
+% for totalBits in [64,128]:
+%  n = totalBits // bits
+%  if n != 1:
+%   neonSuffix = str(n) + {8:'b',16:'h',32:'s',64:'d'}[bits]
+func repeating${n}_uint${bits}(_ scalar: UInt${bits}) -> SIMD${n}<UInt${bits}> {
+  SIMD${n}(repeating: scalar)
+}
+// CHECK: repeating${n}_uint${bits}{{.*}} {
+// CHECK: entry:
+// CHECK: [[TMP:%[0-9]+]] = insertelement <${n} x i${bits}> {{.*}}, i${bits} %{{.*}}, i32 0
+// CHECK-NEXT: [[REP:%[0-9]+]] = shufflevector <${n} x i${bits}> [[TMP]], <${n} x i${bits}> {{.*}}, <${n} x i32> zeroinitializer
+
+%  end
+% end
+%end
diff --git a/test/stdlib/SetTraps.swift b/test/stdlib/SetTraps.swift
index 00ccf5925afee..ccdaa72480579 100644
--- a/test/stdlib/SetTraps.swift
+++ b/test/stdlib/SetTraps.swift
@@ -7,7 +7,7 @@
 // RUN: %target-run %t/a.out_Debug
 // RUN: %target-run %t/a.out_Release
 // REQUIRES: executable_test
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 import StdlibUnittest
 
diff --git a/test/stdlib/Span/BoundsCheckOptimization.swift b/test/stdlib/Span/BoundsCheckOptimization.swift
new file mode 100644
index 0000000000000..59544891d86ea
--- /dev/null
+++ b/test/stdlib/Span/BoundsCheckOptimization.swift
@@ -0,0 +1,62 @@
+//===--- BoundsCheckOptimization.swift ------------------------*- swift -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// RUN: %target-swift-frontend -primary-file %s -O -emit-assembly | %FileCheck %s --check-prefix CHECK --check-prefix CHECK-%target-cpu
+// REQUIRES: swift_stdlib_no_asserts
+
+import Swift
+
+func read(index: Int, span: Span<UInt8>) -> UInt8 {
+  span[index]
+}
+// CHECK: s23BoundsCheckOptimization4read5index4spans5UInt8VSi_s4SpanVyAFGtF:
+
+// CHECK-arm64-NOT: tbnz
+// CHECK-arm64: cmp
+// all unsigned comparison spellings?
+// CHECK-arm64-NEXT: b.{{hs|hi|ls|lo|cc|cs}}
+// CHECK-arm64-NEXT: ldrb
+// CHECK-arm64-NEXT: ret
+
+// CHECK-x86_64-NOT: test
+// CHECK-x86_64: cmp
+// all unsigned comparison spellings?
+// CHECK-x86_64-NEXT: j{{a|ae|b|be|c|na|nae|nb|nbe|nc}}
+// CHECK-x86_64-NEXT: movzb
+// x86_64 might have a frame pointer operation before ret
+
+func write(value: UInt8, index: Int, span: inout MutableSpan<UInt8>) {
+  span[index] = value
+}
+// CHECK: s23BoundsCheckOptimization5write5value5index4spanys5UInt8V_Sis11MutableSpanVyAGGztF:
+
+// CHECK-arm64-NOT: tbnz
+// CHECK-arm64: cmp
+// all unsigned comparison spellings?
+// CHECK-arm64-NEXT: b.{{hs|hi|ls|lo|cc|cs}}
+// no second compare
+// CHECK-arm64-NOT: cmp
+// no test after compare
+// CHECK-arm64-NOT: tbnz
+// CHECK-arm64: strb
+// CHECK-arm64-NEXT: ret
+
+// CHECK-x86_64-NOT: test
+// CHECK-x86_64: cmp
+// all unsigned comparison spellings?
+// CHECK-x86_64-NEXT: j{{a|ae|b|be|c|na|nae|nb|nbe|nc}}
+// no second compare
+// CHECK-x86_64-NOT: cmp
+// no test after compare
+// CHECK-x86_64-NOT: test
+// CHECK-x86_64: movb
+// x86_64 might have a frame pointer operation before ret
diff --git a/test/stdlib/Span/BridgedStringUTF8ViewSpanTests.swift b/test/stdlib/Span/BridgedStringUTF8ViewSpanTests.swift
index 577f09fcb383f..a779e430e1012 100644
--- a/test/stdlib/Span/BridgedStringUTF8ViewSpanTests.swift
+++ b/test/stdlib/Span/BridgedStringUTF8ViewSpanTests.swift
@@ -10,11 +10,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-// RUN: %target-run-stdlib-swift -enable-experimental-feature LifetimeDependence
+// RUN: %target-run-stdlib-swift
 
 // REQUIRES: executable_test
 // REQUIRES: objc_interop
-// REQUIRES: swift_feature_LifetimeDependence
 
 import StdlibUnittest
 
@@ -25,12 +24,12 @@ defer { runAllTests() }
 
 let strings = [
   "Hello, World!",
+  "123456789",
   "A long ASCII string exceeding 16 code units.",
   "🇯🇵",
   "🏂☃❅❆❄︎⛄️❄️",
-// Enable the following once the small native string form is supported
-//  "z",
-//  "",
+  "z",
+  "",
 ]
 
 strings.forEach { expected in
@@ -38,13 +37,12 @@ strings.forEach { expected in
   .require(.stdlib_6_2).code {
     guard #available(SwiftStdlib 6.2, *) else { return }
 
-    let string = NSString(utf8String: expected)
-    guard let string else { expectNotNil(string); return }
+    guard let nss = expectNotNil(NSString(utf8String: expected)) else { return }
 
-    let bridged = String(string).utf8
+    let bridged = String(nss).utf8
     var p: ObjectIdentifier? = nil
     for (i, j) in zip(0..<3, bridged.indices) {
-      let span = bridged.span
+      guard let span = expectNotNil(bridged._span) else { continue }
       let c = span.withUnsafeBufferPointer {
         let o = unsafeBitCast($0.baseAddress, to: ObjectIdentifier.self)
         if p == nil {
@@ -64,12 +62,11 @@ strings.forEach { expected in
   .require(.stdlib_6_2).code {
     guard #available(SwiftStdlib 6.2, *) else { return }
 
-    let string = NSString(utf8String: expected)
-    guard let string else { expectNotNil(string); return }
+    guard let nss = expectNotNil(NSString(utf8String: expected)) else { return }
 
-    let bridged = String(string)
+    let bridged = String(nss)
     let utf8 = bridged.utf8
-    let span = utf8.span
+    guard let span = expectNotNil(utf8._span) else { return }
     expectEqual(span.count, expected.utf8.count)
     for (i,j) in zip(span.indices, expected.utf8.indices) {
       expectEqual(span[i], expected.utf8[j])
@@ -77,21 +74,53 @@ strings.forEach { expected in
   }
 }
 
+strings.forEach { expected in
+  suite.test("UTF8Span from Bridged String: \(expected)")
+  .require(.stdlib_6_2).code {
+    guard #available(SwiftStdlib 6.2, *) else { return }
+
+    guard let nss = expectNotNil(NSString(utf8String: expected)) else { return }
+
+    let bridged = String(nss)
+    guard let utf8 = expectNotNil(bridged._utf8Span) else { return }
+    expectEqual(utf8.count, expected.utf8.count)
+    for (i,j) in zip(utf8.span.indices, expected.utf8.indices) {
+      expectEqual(utf8.span[i], expected.utf8[j])
+    }
+  }
+}
+
 strings.forEach { expected in
   suite.test("Span from Bridged String Substring: \(expected)")
   .require(.stdlib_6_2).code {
     guard #available(SwiftStdlib 6.2, *) else { return }
 
-    let string = NSString(utf8String: expected)
-    guard let string else { expectNotNil(string); return }
+    guard let nss = expectNotNil(NSString(utf8String: expected)) else { return }
 
-    let bridged = String(string).dropFirst()
+    let bridged = String(nss).dropFirst()
     let utf8 = bridged.utf8
-    let span = utf8.span
+    guard let span = expectNotNil(utf8._span) else { return }
     let expected = expected.dropFirst()
     expectEqual(span.count, expected.utf8.count)
     for (i,j) in zip(span.indices, expected.utf8.indices) {
       expectEqual(span[i], expected.utf8[j])
     }
   }
+
+  strings.forEach { expected in
+    suite.test("UTF8Span from Bridged String Substring: \(expected)")
+    .require(.stdlib_6_2).code {
+      guard #available(SwiftStdlib 6.2, *) else { return }
+
+      guard let nss = expectNotNil(NSString(utf8String: expected)) else { return }
+
+      let bridged = String(nss).dropFirst()
+      guard let utf8 = expectNotNil(bridged._utf8Span) else { return }
+      let expected = expected.dropFirst()
+      expectEqual(utf8.count, expected.utf8.count)
+      for (i,j) in zip(utf8.span.indices, expected.utf8.indices) {
+        expectEqual(utf8.span[i], expected.utf8[j])
+      }
+    }
+  }
 }
diff --git a/test/stdlib/Span/InlineSpanProperties.swift b/test/stdlib/Span/InlineSpanProperties.swift
index 1f040bd5296c7..252d2990e9fac 100644
--- a/test/stdlib/Span/InlineSpanProperties.swift
+++ b/test/stdlib/Span/InlineSpanProperties.swift
@@ -23,7 +23,6 @@ var suite = TestSuite("Span properties backed by inline storage")
 defer { runAllTests() }
 
 suite.test("CollectionOfOne.span property")
-.skip(.wasiAny(reason: "Trap tests aren't supported on WASI."))
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -35,7 +34,6 @@ suite.test("CollectionOfOne.span property")
   let u = Array(s.utf8)
   let c = CollectionOfOne(consume s)
   s = ""
-  expectCrashLater()
   let span = c.span
   expectEqual(span.count, 1)
   let v = Array(span[0].utf8)
@@ -43,7 +41,6 @@ suite.test("CollectionOfOne.span property")
 }
 
 suite.test("CollectionOfOne.span property (simple)")
-.skip(.wasiAny(reason: "Trap tests aren't supported on WASI."))
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -52,7 +49,6 @@ suite.test("CollectionOfOne.span property (simple)")
   guard #available(SwiftStdlib 6.2, *) else { return }
   
   let c = CollectionOfOne(Int.random(in: 0..<100000))
-  expectCrashLater()
   let span = c.span
   expectEqual(span.count, c.indices.count)
   expectEqual(span[0], c[0])
@@ -63,7 +59,6 @@ struct Padded: BitwiseCopyable {
 }
 
 suite.test("CollectionOfOne.span stride test")
-.skip(.wasiAny(reason: "Trap tests aren't supported on WASI."))
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -72,14 +67,25 @@ suite.test("CollectionOfOne.span stride test")
   guard #available(SwiftStdlib 6.2, *) else { return }
 
   let c = CollectionOfOne(Padded(storage: (-1, 1)))
-  expectCrashLater()
   let span = c.span
   let bytes = span.bytes
   expectEqual(bytes.byteCount, MemoryLayout.size(ofValue: c))
 }
 
+suite.test("CollectionOfOne.mutableSpan property (simple)")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var c = CollectionOfOne(Int.random(in: 0..<100000))
+  expectEqual(c.count, 1)
+  var span = c.mutableSpan
+  expectEqual(span.count, 1)
+  span[0] = Int.random(in: .min..<0)
+  let r = span[0]
+  expectEqual(c[0], r)
+}
+
 suite.test("InlineArray.span property")
-.skip(.wasiAny(reason: "Trap tests aren't supported on WASI."))
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -89,7 +95,6 @@ suite.test("InlineArray.span property")
 
   var s = InlineArray<5, Int>(repeating: 0)
   s[3] = .random(in: 0..<1000)
-  expectCrashLater()
   let span = s.span
   expectEqual(span.count, s.count)
   for i in s.indices {
@@ -98,7 +103,6 @@ suite.test("InlineArray.span property")
 }
 
 suite.test("InlineArray.span property (String)")
-.skip(.wasiAny(reason: "Trap tests aren't supported on WASI."))
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -108,10 +112,37 @@ suite.test("InlineArray.span property (String)")
 
   var s = InlineArray<5, String>(repeating: "0")
   s[3] = String(Int.random(in: 0..<1000))
-  expectCrashLater()
   let span = s.span
   expectEqual(span.count, s.count)
   for i in s.indices {
     expectEqual(span[i], s[i])
   }    
 }
+
+suite.test("InlineArray.mutableSpan property")
+.require(.stdlib_6_2).code
+{
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var v = InlineArray<5, Int>(repeating: 0)
+  let c = v.count
+  var span = v.mutableSpan
+  expectEqual(span.count, c)
+  span[3] = Int.random(in: .min..<0)
+  let r = span[3]
+  expectEqual(v[3], r)
+}
+
+suite.test("InlineArray.mutableSpan property (String)")
+.require(.stdlib_6_2).code
+{
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var v = InlineArray<5, String>(repeating: "0")
+  let c = v.count
+  var span = v.mutableSpan
+  expectEqual(span.count, c)
+  span[3] = String(repeating: "0", count: Int.random(in: 100..<500))
+  let s = span[3]
+  expectTrue(s._isIdentical(to: v[3]))
+}
diff --git a/test/stdlib/Span/MutableRawSpanTests.swift b/test/stdlib/Span/MutableRawSpanTests.swift
index e64558bd0ef3b..a0ace439b58ad 100644
--- a/test/stdlib/Span/MutableRawSpanTests.swift
+++ b/test/stdlib/Span/MutableRawSpanTests.swift
@@ -29,10 +29,13 @@ suite.test("Basic Initializer")
 
   var s = Array("\(#file)+\(#function)--\(Int.random(in: 1000...9999))".utf8)
   s.withUnsafeMutableBytes {
-    let b = MutableRawSpan(_unsafeBytes: $0)
+    var b = MutableRawSpan(_unsafeBytes: $0)
     expectEqual(b.byteCount, $0.count)
     expectFalse(b.isEmpty)
     expectEqual(b.byteOffsets, 0..<$0.count)
+
+    b = MutableRawSpan()
+    expectEqual(b.byteCount, 0)
   }
 }
 
@@ -246,7 +249,7 @@ suite.test("unsafeLoadUnaligned(as:)")
   a.withUnsafeMutableBytes {
     var span = MutableRawSpan(_unsafeBytes: $0)
 
-    let suffix = span.extracting(droppingFirst: 2)
+    let suffix = span._mutatingExtracting(droppingFirst: 2)
     let u0 = suffix.unsafeLoadUnaligned(as: UInt64.self)
     expectEqual(u0 & 0xff, 2)
     expectEqual(u0.byteSwapped & 0xff, 9)
@@ -278,111 +281,7 @@ suite.test("storeBytes(of:as:)")
   expectEqual(a[0].bigEndian & 0xffff, 0xffff)
 }
 
-suite.test("update(from: some Sequence<some BitwiseCopyable>)")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: Int.max, count: capacity)
-  expectEqual(a.allSatisfy({ $0 == .max }), true)
-  a.withUnsafeMutableBufferPointer {
-    let empty = UnsafeMutableBufferPointer<Int>(start: nil, count: 0)
-    var span = MutableRawSpan(_unsafeElements: empty)
-    var (iterator, updated) = span.update(from: 0..<0)
-    expectNil(iterator.next())
-    expectEqual(updated, 0)
-
-    span = MutableRawSpan(_unsafeElements: $0)
-    (iterator, updated) = span.update(from: 0..<0)
-    expectNil(iterator.next())
-    expectEqual(updated, 0)
-
-    (iterator, updated) = span.update(from: 0..<10000)
-    expectNotNil(iterator.next())
-    expectEqual(updated, capacity*MemoryLayout<Int>.stride)
-  }
-  expectEqual(a.elementsEqual(0..<capacity), true)
-}
-
-suite.test("update(from: some Collection<some BitwiseCopyable>)")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: Int.max, count: capacity)
-  let e = Array(EmptyCollection<UInt>())
-  expectEqual(a.allSatisfy({ $0 == .max }), true)
-  a.withUnsafeMutableBytes {
-    let emptyPrefix = $0.prefix(0)
-    var span = MutableRawSpan(_unsafeBytes: emptyPrefix)
-    var updated = span.update(fromContentsOf: e)
-    expectEqual(updated, 0)
-
-
-    updated = span.update(fromContentsOf: AnyCollection(e))
-    expectEqual(updated, 0)
-
-    span = MutableRawSpan(_unsafeBytes: $0)
-    updated = span.update(fromContentsOf: 0..<capacity)
-    expectEqual(updated, capacity*MemoryLayout<Int>.stride)
-  }
-  expectEqual(a.elementsEqual(0..<capacity), true)
-}
-
-suite.test("update(fromContentsOf:) (contiguous memory)")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: Int.max, count: capacity)
-  expectEqual(a.allSatisfy({ $0 == .max }), true)
-  a.withUnsafeMutableBytes {
-    var span = MutableRawSpan(_unsafeBytes: $0)
-    let array = Array(0..<capacity)
-    var updated = span.update(fromContentsOf: array.prefix(0))
-    expectEqual(updated, 0)
-
-    updated = span.update(fromContentsOf: array)
-    expectEqual(updated, capacity*MemoryLayout<Int>.stride)
-  }
-  expectEqual(a.elementsEqual(0..<capacity), true)
-
-  a.withUnsafeMutableBytes {
-    var span = MutableRawSpan(_unsafeBytes: $0)
-    var array = Array(repeating: Int.min, count: capacity)
-    array.withUnsafeMutableBytes {
-      let source = MutableRawSpan(_unsafeBytes: $0)
-      let updated = span.update(fromContentsOf: source)
-      expectEqual(updated, capacity*MemoryLayout<Int>.stride)
-    }
-  }
-  expectEqual(a.allSatisfy({ $0 == Int.min }), true)
-
-  a.withUnsafeMutableBytes {
-    var span = MutableRawSpan(_unsafeBytes: $0)
-    let array = Array(0..<capacity)
-    array.withUnsafeBufferPointer {
-      let source = Span(_unsafeElements: $0)
-      let updated = span.update(fromContentsOf: source)
-      expectEqual(updated, capacity*MemoryLayout<Int>.stride)
-    }
-  }
-  expectEqual(a.elementsEqual(0..<capacity), true)
-}
-
-suite.test("extracting()")
+suite.test("_mutatingExtracting()")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -395,25 +294,54 @@ suite.test("extracting()")
   b.withUnsafeMutableBytes {
     var span = MutableRawSpan(_unsafeBytes: $0)
 
-    var sub = span.extracting(0..<2)
+    var sub = span._mutatingExtracting(0..<2)
     expectEqual(sub.byteCount, 2)
     expectEqual(sub.unsafeLoad(as: UInt8.self), 0)
 
-    sub = span.extracting(..<2)
+    sub = span._mutatingExtracting(..<2)
     expectEqual(sub.byteCount, 2)
     expectEqual(sub.unsafeLoad(as: UInt8.self), 0)
 
-    sub = span.extracting(...)
+    sub = span._mutatingExtracting(...)
     expectEqual(sub.byteCount, 4)
     expectEqual(sub.unsafeLoad(as: UInt8.self), 0)
 
-    sub = span.extracting(2...)
+    sub = span._mutatingExtracting(2...)
     expectEqual(sub.byteCount, 2)
     expectEqual(sub.unsafeLoad(as: UInt8.self), 2)
   }
 }
 
-suite.test("extracting(unchecked:)")
+suite.test("_consumingExtracting()")
+.require(.stdlib_6_2).code {
+
+  let c = 16
+  let b = UnsafeMutableRawBufferPointer.allocate(byteCount: c, alignment: c)
+  defer { b.deallocate() }
+  _ = b.initializeMemory(as: UInt8.self, from: 0..<UInt8(c))
+
+  var span = b.mutableBytes
+  span = span._consumingExtracting(0..<2)
+  expectEqual(span.byteCount, 2)
+  expectEqual(span.unsafeLoad(as: UInt8.self), 0)
+
+  span = b.mutableBytes
+  span = span._consumingExtracting(..<2)
+  expectEqual(span.byteCount, 2)
+  expectEqual(span.unsafeLoad(as: UInt8.self), 0)
+
+  span = b.mutableBytes
+  span = span._consumingExtracting(...)
+  expectEqual(span.byteCount, c)
+  expectEqual(span.unsafeLoad(as: UInt8.self), 0)
+
+  span = b.mutableBytes
+  span = span._consumingExtracting(2...)
+  expectEqual(span.byteCount, c-2)
+  expectEqual(span.unsafeLoad(as: UInt8.self), 2)
+}
+
+suite.test("_mutatingExtracting(unchecked:)")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -425,14 +353,28 @@ suite.test("extracting(unchecked:)")
   var b = (0..<capacity).map(UInt8.init)
   b.withUnsafeMutableBytes {
     var span = MutableRawSpan(_unsafeBytes: $0.prefix(8))
-    let beyond = span.extracting(unchecked: 16...23)
+    let beyond = span._mutatingExtracting(unchecked: 16...23)
+    expectEqual(beyond.byteCount, 8)
+    let fromBeyond = beyond.unsafeLoad(as: UInt8.self)
+    expectEqual(fromBeyond, 16)
+  }
+}
+
+suite.test("_consumingExtracting(unchecked:)")
+.require(.stdlib_6_2).code {
+
+  let capacity = 32
+  var b = (0..<capacity).map(UInt8.init)
+  b.withUnsafeMutableBytes {
+    let span = MutableRawSpan(_unsafeBytes: $0.prefix(8))
+    let beyond = span._consumingExtracting(unchecked: 16...23)
     expectEqual(beyond.byteCount, 8)
     let fromBeyond = beyond.unsafeLoad(as: UInt8.self)
     expectEqual(fromBeyond, 16)
   }
 }
 
-suite.test("extracting prefixes")
+suite.test("_mutatingExtracting prefixes")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -447,19 +389,19 @@ suite.test("extracting prefixes")
     var span = MutableRawSpan(_unsafeBytes: $0)
     expectEqual(span.byteCount, capacity)
 
-    prefix = span.extracting(first: 1)
+    prefix = span._mutatingExtracting(first: 1)
     expectEqual(prefix.unsafeLoad(as: UInt8.self), 0)
 
-    prefix = span.extracting(first: capacity)
+    prefix = span._mutatingExtracting(first: capacity)
     expectEqual(
       prefix.unsafeLoad(fromByteOffset: capacity-1, as: UInt8.self),
       UInt8(capacity-1)
     )
 
-    prefix = span.extracting(droppingLast: capacity)
+    prefix = span._mutatingExtracting(droppingLast: capacity)
     expectEqual(prefix.isEmpty, true)
 
-    prefix = span.extracting(droppingLast: 1)
+    prefix = span._mutatingExtracting(droppingLast: 1)
     expectEqual(
       prefix.unsafeLoad(fromByteOffset: capacity-2, as: UInt8.self),
       UInt8(capacity-2)
@@ -470,12 +412,51 @@ suite.test("extracting prefixes")
     let b = UnsafeMutableRawBufferPointer(start: nil, count: 0)
     var span = MutableRawSpan(_unsafeBytes: b)
     expectEqual(span.byteCount, b.count)
-    expectEqual(span.extracting(first: 1).byteCount, b.count)
-    expectEqual(span.extracting(droppingLast: 1).byteCount, b.count)
+    expectEqual(span._mutatingExtracting(first: 1).byteCount, b.count)
+    expectEqual(span._mutatingExtracting(droppingLast: 1).byteCount, b.count)
   }
 }
 
-suite.test("extracting suffixes")
+suite.test("_consumingExtracting prefixes")
+.require(.stdlib_6_2).code {
+
+  let capacity = 4
+  var a = Array(0..<UInt8(capacity))
+  a.withUnsafeMutableBytes {
+    var span = $0.mutableBytes
+    expectEqual(span.byteCount, capacity)
+
+    span = span._consumingExtracting(first: 1)
+    expectEqual(span.unsafeLoad(as: UInt8.self), 0)
+
+    span = $0.mutableBytes._consumingExtracting(first: capacity)
+    expectEqual(
+      span.unsafeLoad(fromByteOffset: capacity-1, as: UInt8.self),
+      UInt8(capacity-1)
+    )
+
+    span = $0.mutableBytes._consumingExtracting(droppingLast: capacity)
+    expectEqual(span.isEmpty, true)
+
+    span = $0.mutableBytes._consumingExtracting(droppingLast: 1)
+    expectEqual(
+      span.unsafeLoad(fromByteOffset: capacity-2, as: UInt8.self),
+      UInt8(capacity-2)
+    )
+  }
+
+  do {
+    let b = UnsafeMutableRawBufferPointer(start: nil, count: 0)
+    var span = MutableRawSpan(_unsafeBytes: b)
+    expectEqual(span.byteCount, b.count)
+    span = b.mutableBytes._consumingExtracting(first: 1)
+    expectEqual(span.byteCount, b.count)
+    span = b.mutableBytes._consumingExtracting(droppingLast: 1)
+    expectEqual(span.byteCount, b.count)
+  }
+}
+
+suite.test("_mutatingExtracting suffixes")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -490,19 +471,19 @@ suite.test("extracting suffixes")
     var span = MutableRawSpan(_unsafeBytes: $0)
     expectEqual(span.byteCount, capacity)
 
-    prefix = span.extracting(last: capacity)
+    prefix = span._mutatingExtracting(last: capacity)
     expectEqual(prefix.unsafeLoad(as: UInt8.self), 0)
 
-    prefix = span.extracting(last: capacity-1)
+    prefix = span._mutatingExtracting(last: capacity-1)
     expectEqual(prefix.unsafeLoad(as: UInt8.self), 1)
 
-    prefix = span.extracting(last: 1)
+    prefix = span._mutatingExtracting(last: 1)
     expectEqual(prefix.unsafeLoad(as: UInt8.self), UInt8(capacity-1))
 
-    prefix = span.extracting(droppingFirst: capacity)
+    prefix = span._mutatingExtracting(droppingFirst: capacity)
     expectTrue(prefix.isEmpty)
 
-    prefix = span.extracting(droppingFirst: 1)
+    prefix = span._mutatingExtracting(droppingFirst: 1)
     expectEqual(prefix.unsafeLoad(as: UInt8.self), 1)
   }
 
@@ -510,7 +491,77 @@ suite.test("extracting suffixes")
     let b = UnsafeMutableRawBufferPointer(start: nil, count: 0)
     var span = MutableRawSpan(_unsafeBytes: b)
     expectEqual(span.byteCount, b.count)
-    expectEqual(span.extracting(last: 1).byteCount, b.count)
-    expectEqual(span.extracting(droppingFirst: 1).byteCount, b.count)
+    expectEqual(span._mutatingExtracting(last: 1).byteCount, b.count)
+    expectEqual(span._mutatingExtracting(droppingFirst: 1).byteCount, b.count)
   }
 }
+
+suite.test("_consumingExtracting suffixes")
+.require(.stdlib_6_2).code {
+
+  let capacity = 4
+  var a = Array(0..<UInt8(capacity))
+  a.withUnsafeMutableBytes {
+    var span = $0.mutableBytes
+    expectEqual(span.byteCount, capacity)
+
+    span = span._consumingExtracting(last: capacity)
+    expectEqual(span.unsafeLoad(as: UInt8.self), 0)
+
+    span = $0.mutableBytes._consumingExtracting(last: capacity-1)
+    expectEqual(span.unsafeLoad(as: UInt8.self), 1)
+
+    span = $0.mutableBytes._consumingExtracting(last: 1)
+    expectEqual(span.unsafeLoad(as: UInt8.self), UInt8(capacity-1))
+
+    span = $0.mutableBytes._consumingExtracting(droppingFirst: capacity)
+    expectEqual(span.isEmpty, true)
+
+    span = $0.mutableBytes._consumingExtracting(droppingFirst: 1)
+    expectEqual(span.unsafeLoad(as: UInt8.self), 1)
+  }
+
+  do {
+    let b = UnsafeMutableRawBufferPointer(start: nil, count: 0)
+    var span = MutableRawSpan(_unsafeBytes: b)
+    expectEqual(span.byteCount, b.count)
+    span = b.mutableBytes._consumingExtracting(last: 1)
+    expectEqual(span.byteCount, b.count)
+    span = b.mutableBytes._consumingExtracting(droppingFirst: 1)
+    expectEqual(span.byteCount, b.count)
+  }
+}
+
+suite.test("MutableRawSpan from UnsafeMutableRawBufferPointer")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let capacity = 4
+  let b = UnsafeMutableRawBufferPointer.allocate(
+    byteCount: capacity*MemoryLayout<Int64>.stride,
+    alignment: MemoryLayout<Int64>.alignment
+  )
+  defer {
+    b.deallocate()
+  }
+  _ = b.initializeMemory(as: Int64.self, fromContentsOf: 0..<Int64(capacity))
+
+  var span = b.mutableBytes
+  span.storeBytes(of: 3, toByteOffset: 10, as: UInt16.self)
+
+  _ = consume span
+
+  let v = b.load(fromByteOffset: 8, as: Int64.self)
+  expectNotEqual(v, 1)
+}
+
+private func send(_: borrowing some Sendable & ~Copyable & ~Escapable) {}
+
+suite.test("MutableRawSpan Sendability")
+.require(.stdlib_6_2).code {
+  let buffer = UnsafeMutableRawBufferPointer.allocate(byteCount: 1, alignment: 2)
+  defer { buffer.deallocate() }
+
+  let span = MutableRawSpan(_unsafeBytes: buffer)
+  send(span)
+}
diff --git a/test/stdlib/Span/MutableSpanTests.swift b/test/stdlib/Span/MutableSpanTests.swift
index 944c049c5f11b..588cd057ab50b 100644
--- a/test/stdlib/Span/MutableSpanTests.swift
+++ b/test/stdlib/Span/MutableSpanTests.swift
@@ -30,9 +30,11 @@ suite.test("Initialize with ordinary element")
   let capacity = 4
   var s = (0..<capacity).map({ "\(#file)+\(#function)--\($0)" })
   s.withUnsafeMutableBufferPointer {
-    let b = MutableSpan(_unsafeElements: $0)
-    let c = b.count
-    expectEqual(c, $0.count)
+    var b = MutableSpan(_unsafeElements: $0)
+    expectEqual(b.count, $0.count)
+
+    b = MutableSpan()
+    expectEqual(b.count, 0)
   }
 }
 
@@ -313,232 +315,6 @@ suite.test("update(repeating:)")
   expectEqual(a.allSatisfy({ $0.id == .max }), true)
 }
 
-suite.test("update(repeating:) - BitwiseCopyable")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  var a = Array(0..<8)
-  expectEqual(a.contains(.max), false)
-  a.withUnsafeMutableBufferPointer {
-    var span = MutableSpan(_unsafeElements: $0)
-    span.update(repeating: .max)
-  }
-  expectEqual(a.allSatisfy({ $0 == .max }), true)
-}
-
-suite.test("update(from: some Sequence)")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: ID(id: .max), count: capacity)
-  expectEqual(a.allSatisfy({ $0.id == .max }), true)
-  a.withUnsafeMutableBufferPointer {
-    let emptyPrefix = $0.prefix(0)
-    var span = MutableSpan(_unsafeElements: emptyPrefix)
-    var (iterator, updated) = span.update(from: [])
-    expectNil(iterator.next())
-    expectEqual(updated, 0)
-
-    span = MutableSpan(_unsafeElements: $0)
-    (iterator, updated) = span.update(from: [])
-    expectNil(iterator.next())
-    expectEqual(updated, 0)
-
-    (iterator, updated) = span.update(from: (0..<12).map(ID.init(id:)))
-    expectNotNil(iterator.next())
-    expectEqual(updated, capacity)
-  }
-  expectEqual(a.map(\.id).elementsEqual(0..<capacity), true)
-}
-
-suite.test("update(from: some Sequence) - BitwiseCopyable")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: Int.max, count: capacity)
-  expectEqual(a.allSatisfy({ $0 == .max }), true)
-  a.withUnsafeMutableBufferPointer {
-    let empty = UnsafeMutableBufferPointer<Int>(start: nil, count: 0)
-    var span = MutableSpan(_unsafeElements: empty)
-    var (iterator, updated) = span.update(from: 0..<0)
-    expectNil(iterator.next())
-    expectEqual(updated, 0)
-
-    span = MutableSpan(_unsafeElements: $0)
-    (iterator, updated) = span.update(from: 0..<0)
-    expectNil(iterator.next())
-    expectEqual(updated, 0)
-
-    (iterator, updated) = span.update(from: 0..<10000)
-    expectNotNil(iterator.next())
-    expectEqual(updated, capacity)
-  }
-  expectEqual(a.elementsEqual(0..<capacity), true)
-}
-
-suite.test("update(fromContentsOf: some Collection)")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: ID(id: .max), count: capacity)
-  expectEqual(a.allSatisfy({ $0.id == .max }), true)
-  a.withUnsafeMutableBufferPointer {
-    let emptyPrefix = $0.prefix(0)
-    var span = MutableSpan(_unsafeElements: emptyPrefix)
-    var updated = span.update(fromContentsOf: [])
-    expectEqual(updated, 0)
-
-    updated = span.update(fromContentsOf: AnyCollection([]))
-    expectEqual(updated, 0)
-
-    span = MutableSpan(_unsafeElements: $0)
-    let elements = (0..<capacity).map(ID.init(id:))
-    updated = span.update(fromContentsOf: AnyCollection(elements))
-    expectEqual(updated, capacity)
-  }
-  expectEqual(a.map(\.id).elementsEqual(0..<capacity), true)
-}
-
-suite.test("update(fromContentsOf: some Collection) - BitwiseCopyable")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: Int.max, count: capacity)
-  expectEqual(a.allSatisfy({ $0 == .max }), true)
-  a.withUnsafeMutableBufferPointer {
-    let emptyPrefix = $0.prefix(0)
-    var span = MutableSpan(_unsafeElements: emptyPrefix)
-    var updated = span.update(fromContentsOf: [])
-    expectEqual(updated, 0)
-
-
-    updated = span.update(fromContentsOf: AnyCollection([]))
-    expectEqual(updated, 0)
-
-    span = MutableSpan(_unsafeElements: $0)
-    updated = span.update(fromContentsOf: 0..<capacity)
-    expectEqual(updated, capacity)
-  }
-  expectEqual(a.elementsEqual(0..<capacity), true)
-}
-
-suite.test("update(fromContentsOf: Span)")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: ID(id: .max), count: capacity)
-  expectEqual(a.allSatisfy({ $0.id == .max }), true)
-  a.withUnsafeMutableBufferPointer {
-    let emptyPrefix = $0.prefix(0)
-    var span = MutableSpan(_unsafeElements: emptyPrefix)
-    let updated = span.update(
-      fromContentsOf: UnsafeBufferPointer(start: nil, count: 0)
-    )
-    expectEqual(updated, 0)
-
-    span = MutableSpan(_unsafeElements: $0)
-    var elements = (0..<capacity).map(ID.init(id:))
-    elements.withUnsafeMutableBufferPointer {
-      let source = MutableSpan(_unsafeElements: $0)
-      let updated = span.update(fromContentsOf: source)
-      expectEqual(updated, capacity)
-    }
-  }
-  expectEqual(a.map(\.id).elementsEqual(0..<capacity), true)
-}
-
-suite.test("update(fromContentsOf: Span) - BitwiseCopyable")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: Int.max, count: capacity)
-  expectEqual(a.allSatisfy({ $0 == .max }), true)
-  a.withUnsafeMutableBufferPointer {
-    let emptyPrefix = $0.prefix(0)
-    var span = MutableSpan(_unsafeElements: emptyPrefix)
-    let update = span.update(fromContentsOf: [])
-    expectEqual(update, 0)
-
-    span = MutableSpan(_unsafeElements: $0)
-    var array = Array(0..<capacity)
-    array.withUnsafeMutableBufferPointer {
-      let source = MutableSpan(_unsafeElements: $0)
-      let update = span.update(fromContentsOf: source)
-      expectEqual(update, capacity)      
-    }
-  }
-  expectEqual(a.elementsEqual(0..<capacity), true)
-}
-
-suite.test("moveUpdate()")
-.skip(.custom(
-  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
-  reason: "Requires Swift 6.2's standard library"
-))
-.code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
-  let capacity = 8
-  var a = Array(repeating: ID(id: .max), count: capacity)
-
-  a.withUnsafeMutableBufferPointer {
-    var span = MutableSpan(_unsafeElements: $0)
-    let empty = UnsafeMutableBufferPointer(start: $0.baseAddress, count: 0)
-    let updated = span.moveUpdate(fromContentsOf: empty)
-    expectEqual(updated, 0)
-  }
-  expectEqual(a.allSatisfy({ $0.id == .max }), true)
-
-  let b = UnsafeMutableBufferPointer<ID>.allocate(capacity: 2*capacity)
-  let i = b.initialize(fromContentsOf: (0..<2*capacity).map(ID.init(id:)))
-  expectEqual(i, 2*capacity)
-
-  a.withUnsafeMutableBufferPointer {
-    var span = MutableSpan(_unsafeElements: $0)
-    let updated = span.moveUpdate(fromContentsOf: b.suffix(capacity))
-    expectEqual(updated, capacity)
-  }
-  expectEqual(a.map(\.id).elementsEqual(capacity..<2*capacity), true)
-
-  a = []
-  b.prefix(capacity).deinitialize()
-  b.deallocate()
-}
-
 suite.test("span property")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
@@ -594,7 +370,7 @@ suite.test("swapAt")
   expectEqual(array, (0..<count).reversed())
 }
 
-suite.test("extracting()")
+suite.test("_mutatingExtracting()")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -607,25 +383,54 @@ suite.test("extracting()")
   b.withUnsafeMutableBufferPointer {
     var span = MutableSpan(_unsafeElements: $0)
 
-    var sub = span.extracting(0..<2)
+    var sub = span._mutatingExtracting(0..<2)
     expectEqual(sub.count, 2)
     expectEqual(sub[0], 0)
 
-    sub = span.extracting(..<2)
+    sub = span._mutatingExtracting(..<2)
     expectEqual(sub.count, 2)
     expectEqual(sub[0], 0)
 
-    sub = span.extracting(...)
+    sub = span._mutatingExtracting(...)
     expectEqual(sub.count, 4)
     expectEqual(sub[0], 0)
 
-    sub = span.extracting(2...)
+    sub = span._mutatingExtracting(2...)
     expectEqual(sub.count, 2)
     expectEqual(sub[0], 2)
   }
 }
 
-suite.test("extracting(unchecked:)")
+suite.test("_consumingExtracting()")
+.require(.stdlib_6_2).code {
+
+  let c = 16
+  let b = UnsafeMutableBufferPointer<Int8>.allocate(capacity: c)
+  defer { b.deallocate() }
+  _ = b.initialize(fromContentsOf: 0..<Int8(c))
+
+  var span = b.mutableSpan
+  span = span._consumingExtracting(0..<2)
+  expectEqual(span.count, 2)
+  expectEqual(span[0], 0)
+
+  span = b.mutableSpan
+  span = span._consumingExtracting(..<2)
+  expectEqual(span.count, 2)
+  expectEqual(span[0], 0)
+
+  span = b.mutableSpan
+  span = span._consumingExtracting(...)
+  expectEqual(span.count, c)
+  expectEqual(span[0], 0)
+
+  span = b.mutableSpan
+  span = span._consumingExtracting(2...)
+  expectEqual(span.count, c-2)
+  expectEqual(span[0], 2)
+}
+
+suite.test("_mutatingExtracting(unchecked:)")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -637,14 +442,27 @@ suite.test("extracting(unchecked:)")
   var b = (0..<capacity).map(UInt8.init)
   b.withUnsafeMutableBufferPointer {
     var span = MutableSpan(_unsafeElements: $0.prefix(8))
-    let beyond = span.extracting(unchecked: 16...23)
+    let beyond = span._mutatingExtracting(unchecked: 16...23)
     expectEqual(beyond.count, 8)
     let fromBeyond = beyond[0]
     expectEqual(fromBeyond, 16)
   }
 }
 
-suite.test("extracting prefixes")
+suite.test("_consumingExtracting(unchecked:)")
+.require(.stdlib_6_2).code {
+
+  let capacity = 32
+  var b = (0..<capacity).map(UInt8.init)
+  b.withUnsafeMutableBufferPointer {
+    let span = MutableSpan(_unsafeElements: $0.prefix(8))
+    let beyond = span._consumingExtracting(unchecked: 16...23)
+    expectEqual(beyond.count, 8)
+    expectEqual(beyond[0], 16)
+  }
+}
+
+suite.test("_mutatingExtracting prefixes")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -659,16 +477,16 @@ suite.test("extracting prefixes")
     var span = MutableSpan(_unsafeElements: $0)
     expectEqual(span.count, capacity)
 
-    prefix = span.extracting(first: 1)
+    prefix = span._mutatingExtracting(first: 1)
     expectEqual(prefix[0], 0)
 
-    prefix = span.extracting(first: capacity)
+    prefix = span._mutatingExtracting(first: capacity)
     expectEqual(prefix[capacity-1], UInt8(capacity-1))
 
-    prefix = span.extracting(droppingLast: capacity)
+    prefix = span._mutatingExtracting(droppingLast: capacity)
     expectEqual(prefix.isEmpty, true)
 
-    prefix = span.extracting(droppingLast: 1)
+    prefix = span._mutatingExtracting(droppingLast: 1)
     expectEqual(prefix[capacity-2], UInt8(capacity-2))
   }
 
@@ -676,12 +494,46 @@ suite.test("extracting prefixes")
     let b = UnsafeMutableBufferPointer<Int>(start: nil, count: 0)
     var span = MutableSpan(_unsafeElements: b)
     expectEqual(span.count, b.count)
-    expectEqual(span.extracting(first: 1).count, b.count)
-    expectEqual(span.extracting(droppingLast: 1).count, b.count)
+    expectEqual(span._mutatingExtracting(first: 1).count, b.count)
+    expectEqual(span._mutatingExtracting(droppingLast: 1).count, b.count)
   }
 }
 
-suite.test("extracting suffixes")
+suite.test("_consumingExtracting prefixes")
+.require(.stdlib_6_2).code {
+
+  let capacity = 4
+  var a = Array(0..<capacity)
+  a.withUnsafeMutableBufferPointer {
+    var span = $0.mutableSpan
+    expectEqual(span.count, capacity)
+
+    span = span._consumingExtracting(first: 1)
+    expectEqual(span.count, 1)
+    expectEqual(span[0], 0)
+
+    span = $0.mutableSpan._consumingExtracting(first: capacity)
+    expectEqual(span[capacity-1], capacity-1)
+
+    span = $0.mutableSpan._consumingExtracting(droppingLast: capacity)
+    expectEqual(span.isEmpty, true)
+
+    span = $0.mutableSpan._consumingExtracting(droppingLast: 1)
+    expectEqual(span[capacity-2], capacity-2)
+  }
+
+  do {
+    let b = UnsafeMutableBufferPointer<Int>(start: nil, count: 0)
+    var span = b.mutableSpan
+    expectEqual(span.count, b.count)
+    span = b.mutableSpan._consumingExtracting(first: 1)
+    expectEqual(span.count, b.count)
+    span = b.mutableSpan._consumingExtracting(droppingLast: 1)
+    expectEqual(span.count, b.count)
+  }
+}
+
+suite.test("_mutatingExtracting suffixes")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -696,19 +548,19 @@ suite.test("extracting suffixes")
     var span = MutableSpan(_unsafeElements: $0)
     expectEqual(span.count, capacity)
 
-    suffix = span.extracting(last: capacity)
+    suffix = span._mutatingExtracting(last: capacity)
     expectEqual(suffix[0], 0)
 
-    suffix = span.extracting(last: capacity-1)
+    suffix = span._mutatingExtracting(last: capacity-1)
     expectEqual(suffix[0], 1)
 
-    suffix = span.extracting(last: 1)
+    suffix = span._mutatingExtracting(last: 1)
     expectEqual(suffix[0], UInt8(capacity-1))
 
-    suffix = span.extracting(droppingFirst: capacity)
+    suffix = span._mutatingExtracting(droppingFirst: capacity)
     expectTrue(suffix.isEmpty)
 
-    suffix = span.extracting(droppingFirst: 1)
+    suffix = span._mutatingExtracting(droppingFirst: 1)
     expectEqual(suffix[0], 1)
   }
 
@@ -716,7 +568,80 @@ suite.test("extracting suffixes")
     let b = UnsafeMutableBufferPointer<ObjectIdentifier>(start: nil, count: 0)
     var span = MutableSpan(_unsafeElements: b)
     expectEqual(span.count, b.count)
-    expectEqual(span.extracting(last: 1).count, b.count)
-    expectEqual(span.extracting(droppingFirst: 1).count, b.count)
+    expectEqual(span._mutatingExtracting(last: 1).count, b.count)
+    expectEqual(span._mutatingExtracting(droppingFirst: 1).count, b.count)
   }
 }
+
+suite.test("_consumingExtracting suffixes")
+.require(.stdlib_6_2).code {
+
+  let capacity = 4
+  var a = Array(0..<capacity)
+  a.withUnsafeMutableBufferPointer {
+    var span = $0.mutableSpan
+    expectEqual(span.count, capacity)
+
+    span = span._consumingExtracting(last: capacity)
+    expectEqual(span[0], 0)
+
+    span = $0.mutableSpan._consumingExtracting(last: capacity-1)
+    expectEqual(span[0], 1)
+
+    span = $0.mutableSpan._consumingExtracting(last: 1)
+    expectEqual(span[0], capacity-1)
+
+    span = $0.mutableSpan._consumingExtracting(droppingFirst: capacity)
+    expectEqual(span.isEmpty, true)
+
+    span = $0.mutableSpan._consumingExtracting(droppingFirst: 1)
+    expectEqual(span[0], 1)
+  }
+
+  do {
+    let b = UnsafeMutableBufferPointer<AnyObject>(start: nil, count: 0)
+    var span = b.mutableSpan
+    expectEqual(span.count, b.count)
+    span = b.mutableSpan._consumingExtracting(last: 1)
+    expectEqual(span.count, b.count)
+    span = b.mutableSpan._consumingExtracting(droppingFirst: 1)
+    expectEqual(span.count, b.count)
+  }
+}
+
+suite.test("MutableSpan from UnsafeMutableBufferPointer")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let capacity = 4
+  let b = UnsafeMutableBufferPointer<Int>.allocate(capacity: capacity)
+  defer {
+    b.deallocate()
+  }
+  _ = b.initialize(fromContentsOf: 0..<capacity)
+
+  var span = b.mutableSpan
+  expectEqual(span.count, capacity)
+
+  span.swapAt(0, 3)
+  span.swapAt(1, 2)
+
+  _ = consume span
+
+  expectTrue(b.elementsEqual((0..<capacity).reversed()))
+}
+
+private func send(_: borrowing some Sendable & ~Copyable & ~Escapable) {}
+
+private struct NCSendable: ~Copyable, Sendable {}
+
+suite.test("MutableSpan Sendability")
+.require(.stdlib_6_2).code {
+  let buffer = UnsafeMutableBufferPointer<NCSendable>.allocate(capacity: 1)
+  defer { buffer.deallocate() }
+  buffer.initializeElement(at: 0, to: NCSendable())
+  defer { buffer.deinitialize() }
+
+  let span = MutableSpan(_unsafeElements: buffer)
+  send(span)
+}
diff --git a/test/stdlib/Span/OutputRawSpanTests.swift b/test/stdlib/Span/OutputRawSpanTests.swift
new file mode 100644
index 0000000000000..c1a334e4fc361
--- /dev/null
+++ b/test/stdlib/Span/OutputRawSpanTests.swift
@@ -0,0 +1,166 @@
+//===--- OutputRawSpanTests.swift -----------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// RUN: %target-run-stdlib-swift
+
+// REQUIRES: executable_test
+
+import StdlibUnittest
+
+var suite = TestSuite("OutputRawSpan Tests")
+defer { runAllTests() }
+
+@available(SwiftStdlib 6.2, *)
+struct Allocation: ~Copyable {
+  let allocation: UnsafeMutableRawBufferPointer
+  var byteCount: Int? = nil
+
+  init(byteCount: Int = 1) {
+    precondition(byteCount >= 0)
+    allocation = .allocate(byteCount: byteCount, alignment: 16)
+  }
+
+  var isEmpty: Bool { (byteCount ?? 0) == 0 }
+
+  mutating func initialize<E>(
+    _ body: (inout OutputRawSpan) throws(E) -> Void
+  ) throws(E) {
+    if byteCount != nil { fatalError() }
+    var outputBuffer = OutputRawSpan(buffer: allocation, initializedCount: 0)
+    do {
+      try body(&outputBuffer)
+      let initialized = outputBuffer.finalize(for: allocation)
+      byteCount = initialized
+    }
+    catch {
+      outputBuffer.removeAll()
+      let initialized = outputBuffer.finalize(for: allocation)
+      assert(initialized == 0)
+      throw error
+    }
+  }
+
+  borrowing func withSpan<E, R: ~Copyable>(
+    _ body: (borrowing RawSpan) throws(E) -> R
+  ) throws(E) -> R {
+    try body(RawSpan(_unsafeBytes: allocation[0..<(byteCount ?? 0)]))
+  }
+
+  deinit {
+    allocation.deallocate()
+  }
+}
+
+enum MyTestError: Error { case error }
+
+suite.test("Create OutputRawSpan")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let c = 48
+  let allocation = UnsafeMutableRawBufferPointer.allocate(byteCount: c, alignment: 16)
+  defer { allocation.deallocate() }
+
+  let ob = unsafe OutputRawSpan(buffer: allocation, initializedCount: 0)
+  let initialized = ob.finalize(for: allocation)
+  expectEqual(initialized, 0)
+}
+
+suite.test("deinit without relinquishing memory")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let c = 48
+  let allocation = UnsafeMutableRawBufferPointer.allocate(byteCount: c, alignment: 16)
+  defer { allocation.deallocate() }
+
+  var ob = unsafe OutputRawSpan(buffer: allocation, initializedCount: 0)
+  // OutputRawSpan(buffer: Slice(base: allocation, bounds: 0..<c))
+  ob.append(repeating: 65, count: 12, as: UInt8.self)
+  expectEqual(ob.byteCount, 12)
+  _ = ob
+}
+
+suite.test("append single elements")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var a = Allocation(byteCount: 48)
+  let c = 10
+  a.initialize {
+    for i in 0...c {
+      $0.append(UInt8(i))
+    }
+    let oops = $0.removeLast()
+    expectEqual(Int(oops), c)
+  }
+  expectNotNil(a.byteCount)
+  expectEqual(a.byteCount, c)
+  a.withSpan {
+    expectEqual($0.byteCount, c)
+    for o in $0.byteOffsets {
+      expectEqual(Int($0.unsafeLoad(fromByteOffset: o, as: UInt8.self)), o)
+    }
+  }
+}
+
+suite.test("initialize buffer with repeated elements")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var a = Allocation(byteCount: 48)
+  let c = UInt8(10)
+  a.initialize {
+    $0.append(repeating: c, count: Int(c), as: UInt8.self)
+    let oops = $0.removeLast()
+    expectEqual(oops, c)
+    expectEqual($0.byteCount, Int(c-1))
+  }
+  a.withSpan {
+    expectEqual($0.byteCount, Int(c-1))
+    for o in $0.byteOffsets {
+      expectEqual($0.unsafeLoad(fromByteOffset: o, as: UInt8.self), c)
+    }
+  }
+}
+
+suite.test("deinitialize buffer")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var a = Allocation(byteCount: 48)
+  do {
+    try a.initialize {
+      $0.append(0)
+      $0.append(1)
+      expectTrue($0.byteCount > 0)
+      throw MyTestError.error
+    }
+  }
+  catch MyTestError.error {
+    expectEqual(a.isEmpty, true)
+  }
+  catch {
+    expectTrue(false)
+  }
+}
+
+private func send(_: borrowing some Sendable & ~Copyable & ~Escapable) {}
+
+suite.test("OutputRawSpan Sendability")
+.require(.stdlib_6_2).code {
+  let buffer = UnsafeMutableRawBufferPointer.allocate(byteCount: 1, alignment: 2)
+  defer { buffer.deallocate() }
+
+  let span = OutputRawSpan(buffer: buffer, initializedCount: 0)
+  send(span)
+}
diff --git a/test/stdlib/Span/OutputSpanTests.swift b/test/stdlib/Span/OutputSpanTests.swift
new file mode 100644
index 0000000000000..e1748be04b24c
--- /dev/null
+++ b/test/stdlib/Span/OutputSpanTests.swift
@@ -0,0 +1,277 @@
+//===--- OutputSpanTests.swift --------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// RUN: %target-run-stdlib-swift
+
+// REQUIRES: executable_test
+
+import StdlibUnittest
+
+var suite = TestSuite("OutputSpan Tests")
+defer { runAllTests() }
+
+@available(SwiftStdlib 6.2, *)
+struct Allocation<T>: ~Copyable {
+  let allocation: UnsafeMutableBufferPointer<T>
+  var count: Int? = nil
+
+  init(of count: Int = 1, _ t: T.Type) {
+    precondition(count >= 0)
+    allocation = .allocate(capacity: count)
+  }
+
+  var isEmpty: Bool { (count ?? 0) == 0 }
+
+  mutating func initialize<E>(
+    _ body: (inout OutputSpan<T>) throws(E) -> Void
+  ) throws(E) {
+    if count != nil { fatalError() }
+    var allocation = allocation
+    if allocation.count == 0 { allocation = .init(start: nil, count: 0) }
+    var outputBuffer = OutputSpan(buffer: allocation, initializedCount: 0)
+    do {
+      try body(&outputBuffer)
+      let initialized = outputBuffer.finalize(for: allocation)
+      count = initialized
+    }
+    catch {
+      outputBuffer.removeAll()
+      let initialized = outputBuffer.finalize(for: allocation)
+      assert(initialized == 0)
+      throw error
+    }
+  }
+
+  borrowing func withSpan<E, R: ~Copyable>(
+    _ body: (borrowing Span<T>) throws(E) -> R
+  ) throws(E) -> R {
+    try body(Span(_unsafeElements: allocation[0..<count!]))
+  }
+
+  deinit {
+    if let count {
+      allocation.prefix(count).deinitialize()
+    }
+    allocation.deallocate()
+  }
+}
+
+enum MyTestError: Error { case error }
+
+suite.test("Create OutputSpan")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let c = 48
+  let allocation = UnsafeMutableBufferPointer<UInt8>.allocate(capacity: c)
+  defer { allocation.deallocate() }
+
+  let ob = unsafe OutputSpan(buffer: allocation, initializedCount: 0)
+  let initialized = ob.finalize(for: allocation)
+  expectEqual(initialized, 0)
+}
+
+suite.test("deinit without relinquishing memory")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let c = 48
+  let allocation = UnsafeMutableBufferPointer<UInt8>.allocate(capacity: c)
+  defer { allocation.deallocate() }
+
+  var ob = unsafe OutputSpan(buffer: allocation, initializedCount: 0)
+  // OutputSpan(buffer: Slice(base: allocation, bounds: 0..<c))
+  ob.append(repeating: 65, count: 12)
+  expectEqual(ob.count, 12)
+  _ = ob
+}
+
+suite.test("append single elements")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var a = Allocation(of: 48, Int.self)
+  let c = 10
+  a.initialize {
+    for i in 0...c {
+      $0.append(i)
+    }
+    let oops = $0.removeLast()
+    expectEqual(oops, c)
+  }
+  expectNotNil(a.count)
+  expectEqual(a.count, c)
+  a.withSpan {
+    expectEqual($0.count, c)
+    for i in $0.indices {
+      expectEqual($0[i], i)
+    }
+  }
+}
+
+suite.test("initialize buffer with repeated elements")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var a = Allocation(of: 48, Int.self)
+  let c = 10
+  a.initialize {
+    $0.append(repeating: c, count: c)
+    let oops = $0.removeLast()
+    expectEqual(oops, c)
+    expectEqual($0.count, c-1)
+  }
+  a.withSpan {
+    expectEqual($0.count, c-1)
+    for i in $0.indices {
+      expectEqual($0[i], c)
+    }
+  }
+}
+
+suite.test("indices property")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let capacity = 4
+  let b = UnsafeMutableBufferPointer<Int>.allocate(capacity: capacity)
+  defer { b.deallocate() }
+  _ = b.initialize(fromContentsOf: 0..<capacity)
+  defer { b.deinitialize() }
+
+  let span = unsafe OutputSpan(buffer: b, initializedCount: capacity)
+  expectEqual(span.indices.count, capacity)
+  let equal = span.indices.elementsEqual(0..<capacity)
+  expectTrue(equal)
+}
+
+suite.test("IndexingSubscript")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let capacity = 4
+  let b = UnsafeMutableBufferPointer<Int>.allocate(capacity: capacity)
+  defer { b.deallocate() }
+  _ = b.initialize(fromContentsOf: 0..<capacity)
+  defer { b.deinitialize() }
+
+  var span = unsafe OutputSpan(buffer: b, initializedCount: capacity)
+  expectEqual(span[0], b.first)
+
+  span[0] += 1
+  expectEqual(span[0], b.first)
+}
+
+suite.test("deinitialize buffer")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var a = Allocation(of: 48, Int.self)
+  do {
+    try a.initialize {
+      $0.append(0)
+      $0.append(1)
+      expectTrue($0.count > 0)
+      throw MyTestError.error
+    }
+  }
+  catch MyTestError.error {
+    expectEqual(a.isEmpty, true)
+  }
+  catch {
+    expectTrue(false)
+  }
+
+  a = Allocation(of: 0, Int.self)
+  do {
+    try a.initialize {
+      expectEqual($0.freeCapacity, 0)
+      throw MyTestError.error
+    }
+  }
+  catch MyTestError.error {
+    expectEqual(a.isEmpty, true)
+  }
+  catch {
+    expectTrue(false)
+  }
+}
+
+suite.test("InlineArray initialization")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let i = InlineArray<10, Int> {
+    (o: inout OutputSpan<Int>) in
+    expectEqual(o.count, 0)
+    for i in 0..<o.capacity {
+      o.append(i)
+    }
+    expectEqual(o.freeCapacity, 0)
+  }
+  for j in i.indices {
+    expectEqual(j, i[j])
+  }
+}
+
+suite.test("InlineArray initialization underflow")
+.skip(.wasiAny(reason: "Trap tests aren't supported on WASI."))
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  expectCrashLater()
+  _ = InlineArray<4, Int> {
+    $0.append(1)
+  }
+}
+
+suite.test("InlineArray initialization throws")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  enum LocalError: Error { case error }
+
+  class I {
+    static var count = 0
+    init() { Self.count += 1 }
+    deinit { Self.count -= 1 }
+  }
+
+  let a: InlineArray<4, I>
+  do throws(LocalError) {
+    a = try InlineArray {
+      o throws(LocalError) in
+      o.append(I())
+      o.append(I())
+      o.append(I())
+      o.append(I())
+      expectEqual(I.count, 4)
+      throw LocalError.error
+    }
+    _ = a
+  } catch {
+    expectEqual(I.count, 0)
+  }
+}
+
+private func send(_: borrowing some Sendable & ~Copyable & ~Escapable) {}
+
+private struct NCSendable: ~Copyable, Sendable {}
+
+suite.test("OutputSpan Sendability")
+.require(.stdlib_6_2).code {
+  let buffer = UnsafeMutableBufferPointer<NCSendable>.allocate(capacity: 1)
+  defer { buffer.deallocate() }
+
+  let span = OutputSpan(buffer: buffer, initializedCount: 0)
+  send(span)
+}
diff --git a/test/stdlib/Span/RawSpanTests.swift b/test/stdlib/Span/RawSpanTests.swift
index 5cfaea46358db..ec96f1fdc0779 100644
--- a/test/stdlib/Span/RawSpanTests.swift
+++ b/test/stdlib/Span/RawSpanTests.swift
@@ -30,9 +30,12 @@ suite.test("Initialize with Span<Int>")
   let capacity = 4
   Array(0..<capacity).withUnsafeBufferPointer {
     let intSpan = Span(_unsafeElements: $0)
-    let span = RawSpan(_elements: intSpan)
+    var span = RawSpan(_elements: intSpan)
     expectEqual(span.byteCount, capacity*MemoryLayout<Int>.stride)
     expectFalse(span.isEmpty)
+
+    span = RawSpan()
+    expectTrue(span.isEmpty)
   }
 
   let a: [Int] = []
@@ -129,7 +132,7 @@ suite.test("unsafeLoadUnaligned(as:)")
   a.withUnsafeBytes {
     let span = RawSpan(_unsafeBytes: $0)
 
-    let suffix = span._extracting(droppingFirst: 2)
+    let suffix = span.extracting(droppingFirst: 2)
     let u0 = suffix.unsafeLoadUnaligned(as: UInt64.self)
     expectEqual(u0.littleEndian & 0xff, 2)
     expectEqual(u0.bigEndian & 0xff, 9)
@@ -139,7 +142,7 @@ suite.test("unsafeLoadUnaligned(as:)")
   }
 }
 
-suite.test("_extracting() functions")
+suite.test("extracting() functions")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -151,10 +154,10 @@ suite.test("_extracting() functions")
   let b = (0..<capacity).map(Int8.init)
   b.withUnsafeBytes {
     let span = RawSpan(_unsafeBytes: $0)
-    let sub1 = span._extracting(0..<2)
-    let sub2 = span._extracting(..<2)
-    let sub3 = span._extracting(...)
-    let sub4 = span._extracting(2...)
+    let sub1 = span.extracting(0..<2)
+    let sub2 = span.extracting(..<2)
+    let sub3 = span.extracting(...)
+    let sub4 = span.extracting(2...)
 
     sub1.withUnsafeBytes { p1 in
       sub2.withUnsafeBytes { p2 in
@@ -174,7 +177,7 @@ suite.test("_extracting() functions")
   }
 }
 
-suite.test("_extracting(unchecked:) functions")
+suite.test("extracting(unchecked:) functions")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -186,14 +189,14 @@ suite.test("_extracting(unchecked:) functions")
   let b = (0..<capacity).map(UInt8.init)
   b.withUnsafeBytes {
     let span = RawSpan(_unsafeBytes: $0)
-    let prefix = span._extracting(0..<8)
-    let beyond = prefix._extracting(unchecked: 16...23)
+    let prefix = span.extracting(0..<8)
+    let beyond = prefix.extracting(unchecked: 16...23)
     expectEqual(beyond.byteCount, 8)
     expectEqual(beyond.unsafeLoad(as: UInt8.self), 16)
   }
 }
 
-suite.test("prefix _extracting() functions")
+suite.test("prefix extracting() functions")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -206,22 +209,22 @@ suite.test("prefix _extracting() functions")
   a.withUnsafeBytes {
     let span = RawSpan(_unsafeBytes: $0)
     expectEqual(span.byteCount, capacity)
-    expectEqual(span._extracting(first: 1).unsafeLoad(as: UInt8.self), 0)
+    expectEqual(span.extracting(first: 1).unsafeLoad(as: UInt8.self), 0)
     expectEqual(
-      span._extracting(first: capacity).unsafeLoad(
+      span.extracting(first: capacity).unsafeLoad(
         fromByteOffset: capacity-1, as: UInt8.self
       ),
       UInt8(capacity-1)
     )
-    expectTrue(span._extracting(droppingLast: capacity).isEmpty)
+    expectTrue(span.extracting(droppingLast: capacity).isEmpty)
     expectEqual(
-      span._extracting(droppingLast: 1).unsafeLoad(
+      span.extracting(droppingLast: 1).unsafeLoad(
         fromByteOffset: capacity-2, as: UInt8.self
       ),
       UInt8(capacity-2)
     )
-    let emptySpan = span._extracting(first: 0)
-    let emptierSpan = emptySpan._extracting(0..<0)
+    let emptySpan = span.extracting(first: 0)
+    let emptierSpan = emptySpan.extracting(0..<0)
     expectTrue(emptySpan.isIdentical(to: emptierSpan))
   }
 
@@ -229,12 +232,12 @@ suite.test("prefix _extracting() functions")
     let b = UnsafeRawBufferPointer(start: nil, count: 0)
     let span = RawSpan(_unsafeBytes: b)
     expectEqual(span.byteCount, b.count)
-    expectEqual(span._extracting(first: 1).byteCount, b.count)
-    expectEqual(span._extracting(droppingLast: 1).byteCount, b.count)
+    expectEqual(span.extracting(first: 1).byteCount, b.count)
+    expectEqual(span.extracting(droppingLast: 1).byteCount, b.count)
   }
 }
 
-suite.test("suffix _extracting() functions")
+suite.test("suffix extracting() functions")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -247,19 +250,19 @@ suite.test("suffix _extracting() functions")
   a.withUnsafeBytes {
     let span = RawSpan(_unsafeBytes: $0)
     expectEqual(span.byteCount, capacity)
-    expectEqual(span._extracting(last: capacity).unsafeLoad(as: UInt8.self), 0)
-    expectEqual(span._extracting(last: capacity-1).unsafeLoad(as: UInt8.self), 1)
-    expectEqual(span._extracting(last: 1).unsafeLoad(as: UInt8.self), UInt8(capacity-1))
-    expectTrue(span._extracting(droppingFirst: capacity).isEmpty)
-    expectEqual(span._extracting(droppingFirst: 1).unsafeLoad(as: UInt8.self), 1)
+    expectEqual(span.extracting(last: capacity).unsafeLoad(as: UInt8.self), 0)
+    expectEqual(span.extracting(last: capacity-1).unsafeLoad(as: UInt8.self), 1)
+    expectEqual(span.extracting(last: 1).unsafeLoad(as: UInt8.self), UInt8(capacity-1))
+    expectTrue(span.extracting(droppingFirst: capacity).isEmpty)
+    expectEqual(span.extracting(droppingFirst: 1).unsafeLoad(as: UInt8.self), 1)
   }
 
   do {
     let b = UnsafeRawBufferPointer(start: nil, count: 0)
     let span = RawSpan(_unsafeBytes: b)
     expectEqual(span.byteCount, b.count)
-    expectEqual(span._extracting(last: 1).byteCount, b.count)
-    expectEqual(span._extracting(droppingFirst: 1).byteCount, b.count)
+    expectEqual(span.extracting(last: 1).byteCount, b.count)
+    expectEqual(span.extracting(droppingFirst: 1).byteCount, b.count)
   }
 }
 
@@ -304,9 +307,9 @@ suite.test("byteOffsets(of:)")
   defer { b.deallocate() }
 
   let span = RawSpan(_unsafeBytes: b)
-  let subSpan1 = span._extracting(first: 6)
-  let subSpan2 = span._extracting(last: 6)
-  let emptySpan = span._extracting(first: 0)
+  let subSpan1 = span.extracting(first: 6)
+  let subSpan2 = span.extracting(last: 6)
+  let emptySpan = span.extracting(first: 0)
   let nilBuffer = UnsafeRawBufferPointer(start: nil, count: 0)
   let nilSpan = RawSpan(_unsafeBytes: nilBuffer)
 
@@ -328,3 +331,14 @@ suite.test("byteOffsets(of:)")
   bounds = nilSpan.byteOffsets(of: nilSpan)
   expectEqual(bounds, 0..<0)
 }
+
+private func send(_: borrowing some Sendable & ~Copyable & ~Escapable) {}
+
+suite.test("RawSpan Sendability")
+.require(.stdlib_6_2).code {
+  let buffer = UnsafeMutableRawBufferPointer.allocate(byteCount: 1, alignment: 2)
+  defer { buffer.deallocate() }
+
+  let span = RawSpan(_unsafeBytes: buffer)
+  send(span)
+}
diff --git a/test/stdlib/Span/SmallStringCompatibility.swift b/test/stdlib/Span/SmallStringCompatibility.swift
new file mode 100644
index 0000000000000..5b460e2f7eb2a
--- /dev/null
+++ b/test/stdlib/Span/SmallStringCompatibility.swift
@@ -0,0 +1,67 @@
+//===--- SmallStringCompatibility.swift -----------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// RUN: %target-run-stdlib-swift
+
+// REQUIRES: executable_test
+// REQUIRES: CPU=wasm32 || CPU=arm64_32
+
+import StdlibUnittest
+
+var suite = TestSuite("SmallStringCompatibility")
+defer { runAllTests() }
+
+var strings = [
+  ("Small", true),
+  ("Less small", true),
+  ("Positively large.", true),
+]
+
+#if os(watchOS)
+strings[1].1 = false
+#endif
+
+strings.forEach { (string, contiguous) in
+  suite.test("Contiguous: \(string)")
+  .require(.stdlib_6_2).code {
+
+    expectEqual(string.isContiguousUTF8, contiguous)
+  }
+}
+
+strings.forEach { (string, contiguous) in
+  suite.test("Contiguous Substring: \(string)")
+  .require(.stdlib_6_2).code {
+    let substring = string[...]
+    expectEqual(substring.isContiguousUTF8, contiguous)
+  }
+}
+
+strings.forEach { (string, contiguous) in
+  suite.test("String.makeContiguousUTF8: \(string)")
+  .require(.stdlib_6_2).code {
+    var s = string
+    s.makeContiguousUTF8()
+    expectTrue(s.isContiguousUTF8)
+    expectEqual(s, string)
+  }
+}
+
+strings.forEach { (string, contiguous) in
+  suite.test("Substring.makeContiguousUTF8: \(string)")
+  .require(.stdlib_6_2).code {
+    var s: Substring = string.dropFirst().dropLast()
+    s.makeContiguousUTF8()
+    expectTrue(s.isContiguousUTF8)
+    expectEqual(s, string.dropFirst().dropLast())
+  }
+}
diff --git a/test/stdlib/Span/SpanTests.swift b/test/stdlib/Span/SpanTests.swift
index f9fab3d7c7633..c5e073f636cf0 100644
--- a/test/stdlib/Span/SpanTests.swift
+++ b/test/stdlib/Span/SpanTests.swift
@@ -120,6 +120,9 @@ suite.test("Initialize with ordinary element")
     let pointer: UnsafeMutablePointer = $0.baseAddress!
     span = Span(_unsafeStart: pointer, count: $0.count)
     expectEqual(span.count, capacity)
+
+    span = Span()
+    expectEqual(span.count, 0)
   }
 }
 
@@ -247,17 +250,17 @@ suite.test("_elementsEqual(_: Span)")
   let capacity = 4
   let a = Array<Int>(unsafeUninitializedCapacity: capacity) {
     for i in $0.indices {
-      $0.initializeElement(at: i, to: .random(in: 0..<10))
+      $0.initializeElement(at: i, to: i)
     }
     $1 = $0.count
   }
   a.withUnsafeBufferPointer {
     let span = Span(_unsafeElements: $0)
 
-    expectEqual(span._elementsEqual(span._extracting(first: 1)), false)
-    expectEqual(span._extracting(0..<0)._elementsEqual(span._extracting(last: 0)), true)
+    expectEqual(span._elementsEqual(span.extracting(first: 1)), false)
+    expectEqual(span.extracting(0..<0)._elementsEqual(span.extracting(last: 0)), true)
     expectEqual(span._elementsEqual(span), true)
-    expectEqual(span._extracting(0..<3)._elementsEqual(span._extracting(last: 3)), false)
+    expectEqual(span.extracting(0..<3)._elementsEqual(span.extracting(last: 3)), false)
 
     let copy = span.withUnsafeBufferPointer(Array.init)
     copy.withUnsafeBufferPointer {
@@ -281,7 +284,7 @@ suite.test("_elementsEqual(_: some Collection)")
     let span = Span(_unsafeElements: $0)
 
     expectEqual(span._elementsEqual(a), true)
-    expectEqual(span._extracting(0..<0)._elementsEqual([]), true)
+    expectEqual(span.extracting(0..<0)._elementsEqual([]), true)
     expectEqual(span._elementsEqual(a.dropLast()), false)
   }
 }
@@ -301,7 +304,7 @@ suite.test("_elementsEqual(_: some Sequence")
 
     let s = AnySequence(a)
     expectEqual(span._elementsEqual(s), true)
-    expectEqual(span._extracting(0..<(capacity-1))._elementsEqual(s), false)
+    expectEqual(span.extracting(0..<(capacity-1))._elementsEqual(s), false)
     expectEqual(span._elementsEqual(s.dropFirst()), false)
   }
 }
@@ -338,7 +341,7 @@ suite.test("subscript with BitwiseCopyable element")
   }
 }
 
-suite.test("_extracting() functions")
+suite.test("extracting() functions")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -350,17 +353,17 @@ suite.test("_extracting() functions")
   let b = (0..<capacity).map(String.init)
   b.withUnsafeBufferPointer {
     let span = Span(_unsafeElements: $0)
-    let sub1 = span._extracting(0..<2)
-    let sub2 = span._extracting(..<2)
-    let sub3 = span._extracting(...)
-    let sub4 = span._extracting(2...)
+    let sub1 = span.extracting(0..<2)
+    let sub2 = span.extracting(..<2)
+    let sub3 = span.extracting(...)
+    let sub4 = span.extracting(2...)
     expectTrue(sub1._elementsEqual(sub2))
     expectTrue(sub3._elementsEqual(span))
     expectFalse(sub4._elementsEqual(sub3))
   }
 }
 
-suite.test("_extracting(unchecked:) functions")
+suite.test("extracting(unchecked:) functions")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -372,14 +375,14 @@ suite.test("_extracting(unchecked:) functions")
   let b = (0..<capacity).map(String.init)
   b.withUnsafeBufferPointer {
     let span = Span(_unsafeElements: $0)
-    let prefix = span._extracting(0..<8)
-    let beyond = prefix._extracting(unchecked: 16...23)
+    let prefix = span.extracting(0..<8)
+    let beyond = prefix.extracting(unchecked: 16...23)
     expectEqual(beyond.count, 8)
     expectEqual(beyond[0], "16")
   }
 }
 
-suite.test("prefix _extracting() functions")
+suite.test("prefix extracting() functions")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -392,22 +395,22 @@ suite.test("prefix _extracting() functions")
   a.withUnsafeBufferPointer {
     let span = Span(_unsafeElements: $0)
     expectEqual(span.count, capacity)
-    expectEqual(span._extracting(first: 1)[0], 0)
-    expectEqual(span._extracting(first: capacity)[capacity-1], capacity-1)
-    expectEqual(span._extracting(droppingLast: capacity).count, 0)
-    expectEqual(span._extracting(droppingLast: 1)[capacity-2], capacity-2)
+    expectEqual(span.extracting(first: 1)[0], 0)
+    expectEqual(span.extracting(first: capacity)[capacity-1], capacity-1)
+    expectEqual(span.extracting(droppingLast: capacity).count, 0)
+    expectEqual(span.extracting(droppingLast: 1)[capacity-2], capacity-2)
   }
 
   do {
     let b = UnsafeBufferPointer<Int>(start: nil, count: 0)
     let span = Span(_unsafeElements: b)
     expectEqual(span.count, b.count)
-    expectEqual(span._extracting(first: 1).count, b.count)
-    expectEqual(span._extracting(droppingLast: 1).count, b.count)
+    expectEqual(span.extracting(first: 1).count, b.count)
+    expectEqual(span.extracting(droppingLast: 1).count, b.count)
   }
 }
 
-suite.test("suffix _extracting() functions")
+suite.test("suffix extracting() functions")
 .skip(.custom(
   { if #available(SwiftStdlib 6.2, *) { false } else { true } },
   reason: "Requires Swift 6.2's standard library"
@@ -420,19 +423,19 @@ suite.test("suffix _extracting() functions")
   a.withUnsafeBufferPointer {
     let span = Span<Int>(_unsafeElements: $0)
     expectEqual(span.count, capacity)
-    expectEqual(span._extracting(last: capacity)[0], 0)
-    expectEqual(span._extracting(last: capacity-1)[0], 1)
-    expectEqual(span._extracting(last: 1)[0], capacity-1)
-    expectEqual(span._extracting(droppingFirst: capacity).count, 0)
-    expectEqual(span._extracting(droppingFirst: 1)[0], 1)
+    expectEqual(span.extracting(last: capacity)[0], 0)
+    expectEqual(span.extracting(last: capacity-1)[0], 1)
+    expectEqual(span.extracting(last: 1)[0], capacity-1)
+    expectEqual(span.extracting(droppingFirst: capacity).count, 0)
+    expectEqual(span.extracting(droppingFirst: 1)[0], 1)
   }
 
   do {
     let b = UnsafeBufferPointer<Int>(start: nil, count: 0)
     let span = Span(_unsafeElements: b)
     expectEqual(span.count, b.count)
-    expectEqual(span._extracting(last: 1).count, b.count)
-    expectEqual(span._extracting(droppingFirst: 1).count, b.count)
+    expectEqual(span.extracting(last: 1).count, b.count)
+    expectEqual(span.extracting(droppingFirst: 1).count, b.count)
   }
 }
 
@@ -506,8 +509,8 @@ suite.test("isIdentical(to:)")
   defer { b.deallocate() }
 
   let span = Span(_unsafeElements: b)
-  let pre = span._extracting(first: 6)
-  let suf = span._extracting(last: 6)
+  let pre = span.extracting(first: 6)
+  let suf = span.extracting(last: 6)
 
   expectFalse(
     pre.isIdentical(to: suf)
@@ -516,7 +519,7 @@ suite.test("isIdentical(to:)")
     pre.isIdentical(to: span)
   )
   expectTrue(
-    pre._extracting(last: 4).isIdentical(to: suf._extracting(first: 4))
+    pre.extracting(last: 4).isIdentical(to: suf.extracting(first: 4))
   )
 }
 
@@ -533,13 +536,13 @@ suite.test("indices(of:)")
   defer { b.deallocate() }
 
   let span = Span(_unsafeElements: b)
-  let subSpan1 = span._extracting(first: 6)
-  let subSpan2 = span._extracting(last: 6)
-  let emptySpan = span._extracting(first: 0)
+  let subSpan1 = span.extracting(first: 6)
+  let subSpan2 = span.extracting(last: 6)
+  let emptySpan = span.extracting(first: 0)
 /*  This isn't relevant until we can support unaligned spans
   let unalignedSpan = RawSpan(_unsafeSpan: span)
-                        ._extracting(droppingFirst: 6)
-                        ._extracting(droppingLast: 2)
+                        .extracting(droppingFirst: 6)
+                        .extracting(droppingLast: 2)
                         .unsafeView(as: Int.self)
 */
   let nilBuffer = UnsafeBufferPointer<Int>(start: nil, count: 0)
@@ -596,8 +599,6 @@ private struct NCSendable: ~Copyable, Sendable {}
 
 suite.test("Span Sendability")
 .require(.stdlib_6_2).code {
-  guard #available(SwiftStdlib 6.2, *) else { return }
-
   let buffer = UnsafeMutableBufferPointer<NCSendable>.allocate(capacity: 1)
   defer { buffer.deallocate() }
   buffer.initializeElement(at: 0, to: NCSendable())
diff --git a/test/stdlib/Span/StringUTF8SpanProperty.swift b/test/stdlib/Span/StringUTF8SpanProperty.swift
index 55b5e7ccdb8b9..b3df04b56d498 100644
--- a/test/stdlib/Span/StringUTF8SpanProperty.swift
+++ b/test/stdlib/Span/StringUTF8SpanProperty.swift
@@ -10,11 +10,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-// RUN: %target-run-stdlib-swift(-enable-experimental-feature LifetimeDependence -enable-experimental-feature AddressableTypes)
+// RUN: %target-run-stdlib-swift
 
 // REQUIRES: executable_test
-// REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_AddressableTypes
 
 import StdlibUnittest
 
@@ -22,14 +20,18 @@ var suite = TestSuite("StringUTF8StorageProperty")
 defer { runAllTests() }
 
 suite.test("Span from Small String")
-.skip(.wasiAny(reason: "Trap tests aren't supported on WASI."))
 .require(.stdlib_6_2).code {
   guard #available(SwiftStdlib 6.2, *) else { return }
 
-  let s = "A small string.".utf8
+  var s = "123456789".utf8
   let u = Array(s)
-  expectCrashLater()
-  let span = s.span
+#if os(watchOS) && _pointerBitWidth(_32)
+  expectNil(s._span)
+#endif
+  var string = String(s)
+  string.reserveCapacity(12)
+  s = (consume string).utf8
+  guard let span = expectNotNil(s._span) else { return }
 
   let count = span.count
   expectEqual(count, s.count)
@@ -45,7 +47,7 @@ suite.test("Span from Large Native String")
 
   let s = "A long string that is altogether not smol.".utf8
   let u = Array(s)
-  let span = s.span
+  guard let span = expectNotNil(s._span) else { return }
 
   let count = span.count
   expectEqual(count, s.count)
@@ -56,14 +58,12 @@ suite.test("Span from Large Native String")
 }
 
 suite.test("Span from Small String's Substring")
-.skip(.wasiAny(reason: "Trap tests aren't supported on WASI."))
 .require(.stdlib_6_2).code {
   guard #available(SwiftStdlib 6.2, *) else { return }
 
   let s = "A small string.".dropFirst(8).utf8
   let u = Array("string.".utf8)
-  expectCrashLater()
-  let span = s.span
+  guard let span = expectNotNil(s._span) else { return }
 
   let count = span.count
   expectEqual(count, s.count)
@@ -80,7 +80,7 @@ suite.test("Span from Large Native String's Substring")
   let t = "A long string that is altogether not smol."
   let s = t.dropFirst(22).prefix(10).utf8
   let u = Array("altogether".utf8)
-  let span = s.span
+  guard let span = expectNotNil(s._span) else { return }
 
   let count = span.count
   expectEqual(count, s.count)
@@ -89,3 +89,45 @@ suite.test("Span from Large Native String's Substring")
     expectEqual(span[i], u[i])
   }
 }
+
+suite.test("Span from String.utf8Span")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let s = String(200)
+  guard let utf8span = expectNotNil(s._utf8Span) else { return }
+  let span1 = utf8span.span
+  let utf8view = s.utf8
+  guard let span2 = expectNotNil(utf8view._span) else { return }
+  expectEqual(span1.count, span2.count)
+  for (i,j) in zip(span1.indices, span2.indices) {
+    expectEqual(span1[i], span2[j])
+  }
+}
+
+suite.test("UTF8Span from Span")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let s = String(200).utf8
+  guard let span1 = expectNotNil(s._span) else { return }
+  guard let utf8 = expectNotNil(try? UTF8Span(validating: span1)) else { return }
+
+  let span2 = utf8.span
+  expectTrue(span1.isIdentical(to: span2))
+}
+
+suite.test("Span from Substring.utf8Span")
+.require(.stdlib_6_2).code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  let s = String(22000).dropFirst().dropLast()
+  guard let utf8span = expectNotNil(s._utf8Span) else { return }
+  let span1 = utf8span.span
+  let utf8view = s.utf8
+  guard let span2 = expectNotNil(utf8view._span) else { return }
+  expectEqual(span1.count, span2.count)
+  for (i,j) in zip(span1.indices, span2.indices) {
+    expectEqual(span1[i], span2[j])
+  }
+}
diff --git a/test/stdlib/StringBridge.swift b/test/stdlib/StringBridge.swift
index 512b6e7fc9362..6754af6bf116a 100644
--- a/test/stdlib/StringBridge.swift
+++ b/test/stdlib/StringBridge.swift
@@ -174,5 +174,25 @@ StringBridgeTests.test("Character from NSString") {
   expectNil((ns3 as String).utf8.withContiguousStorageIfAvailable(returnOne))
 }
 
+StringBridgeTests.test("lengthOfBytes(using:)") {
+  let ascii = "The quick brown fox jumps over the lazy dog"
+  let utf8 = "The quick brown fox jümps over the lazy dog"
+  let asciiAsASCIILen = ascii.lengthOfBytes(using: .ascii)
+  let asciiAsUTF8Len = ascii.lengthOfBytes(using: .utf8)
+  let asciiAsUTF16Len = ascii.lengthOfBytes(using: .utf16)
+  let asciiAsMacRomanLen = ascii.lengthOfBytes(using: .macOSRoman)
+  let utf8AsASCIILen = utf8.lengthOfBytes(using: .ascii)
+  let utf8AsUTF8Len = utf8.lengthOfBytes(using: .utf8)
+  let utf8AsUTF16Len = utf8.lengthOfBytes(using: .utf16)
+  let utf8AsMacRomanLen = utf8.lengthOfBytes(using: .macOSRoman)
+  expectEqual(asciiAsASCIILen, 43)
+  expectEqual(asciiAsUTF8Len, 43)
+  expectEqual(asciiAsUTF16Len, 86)
+  expectEqual(asciiAsMacRomanLen, 43)
+  expectEqual(utf8AsASCIILen, 0)
+  expectEqual(utf8AsUTF8Len, 44)
+  expectEqual(utf8AsUTF16Len, 86)
+  expectEqual(utf8AsMacRomanLen, 43)
+}
 
 runAllTests()
diff --git a/test/stdlib/StringCompatibilityDiagnostics.swift b/test/stdlib/StringCompatibilityDiagnostics.swift
index c69144f71fffa..b9cf48bca381e 100644
--- a/test/stdlib/StringCompatibilityDiagnostics.swift
+++ b/test/stdlib/StringCompatibilityDiagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -swift-version 5 %s -verify
+// RUN: %target-swift-frontend -typecheck -swift-version 5 %s -verify -verify-ignore-unrelated
 
 func testPopFirst() {
   let str = "abc"
diff --git a/test/stdlib/StringDeconstruction.swift b/test/stdlib/StringDeconstruction.swift
index 8e159f061dc6f..7e3f5d9103548 100644
--- a/test/stdlib/StringDeconstruction.swift
+++ b/test/stdlib/StringDeconstruction.swift
@@ -94,8 +94,10 @@ func id<T>(_ a: T) -> T { a }
 StringDeconstructTests.test("deconstruct") {
   let smallASCII = "abcd"
 
-#if _pointerBitWidth(_32)
+#if _pointerBitWidth(_32) && os(watchOS)
   let smallUTF8 = "ジッパ"
+#elseif _pointerBitWidth(_32)
+  let smallUTF8 = "ジッ"
 #else
   let smallUTF8 = "ジッパー"
 #endif
diff --git a/test/stdlib/StringDiagnostics.swift b/test/stdlib/StringDiagnostics.swift
index 3a53a26c69ee0..7978947436c54 100644
--- a/test/stdlib/StringDiagnostics.swift
+++ b/test/stdlib/StringDiagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // REQUIRES: objc_interop
 
diff --git a/test/stdlib/StringIndex.swift b/test/stdlib/StringIndex.swift
index 6f20537a72c7b..9cb3ec017fbf7 100644
--- a/test/stdlib/StringIndex.swift
+++ b/test/stdlib/StringIndex.swift
@@ -1243,7 +1243,11 @@ if #available(SwiftStdlib 6.1, *) {
 suite.test("String index debugDescription backdeployment") {
   // Note: no availability check
   let str = "i\u{308}"
-  expectEqual(str.startIndex.debugDescription, "0[any]")
+  // Result can be `any` or `unknown` depending on inlining behavior
+  expectTrue(
+    str.startIndex.debugDescription == "0[any]" ||
+    str.startIndex.debugDescription == "0[unknown]"
+  )
   expectEqual(str.endIndex.debugDescription, "3[utf8]")
 }
 
diff --git a/test/stdlib/StringTraps.swift b/test/stdlib/StringTraps.swift
index 78ee0649d5225..838876fce2cf9 100644
--- a/test/stdlib/StringTraps.swift
+++ b/test/stdlib/StringTraps.swift
@@ -11,7 +11,7 @@
 // 5.7 so that we can test new behavior even if the SDK we're using predates it.
 
 // REQUIRES: executable_test
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 import StdlibUnittest
 #if _runtime(_ObjC)
diff --git a/test/stdlib/TemporaryAllocation.swift b/test/stdlib/TemporaryAllocation.swift
index 494d20ce234fe..4d4eb31bb9128 100644
--- a/test/stdlib/TemporaryAllocation.swift
+++ b/test/stdlib/TemporaryAllocation.swift
@@ -155,4 +155,21 @@ TemporaryAllocationTestSuite.test("typedAllocationIsAligned") {
   }
 }
 
+// MARK: Typed throws
+enum HomeworkError: Error, Equatable {
+case dogAteIt
+case forgot
+}
+
+TemporaryAllocationTestSuite.test("typedAllocationWithThrow") {
+  do throws(HomeworkError) {
+    try withUnsafeTemporaryAllocation(of: Int.self, capacity: 1) { (buffer) throws(HomeworkError) -> Void in
+      throw HomeworkError.forgot
+    }
+    fatalError("did not throw!?!")
+  } catch {
+    expectEqual(error, .forgot)
+  }
+}
+
 runAllTests()
diff --git a/test/stdlib/UTF8EncodingErrorTests.swift b/test/stdlib/UTF8EncodingErrorTests.swift
new file mode 100644
index 0000000000000..de6893a1ebab1
--- /dev/null
+++ b/test/stdlib/UTF8EncodingErrorTests.swift
@@ -0,0 +1,295 @@
+// RUN: %target-run-stdlib-swift %S/Inputs/
+
+// REQUIRES: executable_test
+
+// FIXME: this test is currently broken
+
+import Swift
+import StdlibUnittest
+
+var suite = TestSuite("UTF8.ValidationError")
+defer { runAllTests() }
+
+@available(SwiftStdlib 6.2, *)
+extension Array {
+  func withSpan<R>(_ f: (Span<Element>) throws -> R) rethrows -> R {
+    try self.withUnsafeBufferPointer {
+      try f(Span(_unsafeElements: $0))
+    }
+  }
+}
+
+
+extension Range<Int> {
+  func _offset(by start: Int) -> Range<Int> {
+    start + lowerBound ..< start + upperBound
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+private struct ValidationError {
+  var error: UTF8.ValidationError
+
+  // When fetching all errors, we'll get the error kind given. When
+  // slicing in order to get the next error (e.g.
+  // `UTF8Span.init(validating:))`, we'll get `.unexpectedContinuation`.
+  var errorStart: Bool
+
+
+  init(
+    _ error: UTF8.ValidationError,
+    errorStart: Bool
+  ) {
+    self.error = error
+    self.errorStart = errorStart
+  }
+
+  public static func unexpectedContinuationByte(
+    at i: Int, errorStart: Bool = true
+  ) -> Self {
+    Self(UTF8.ValidationError(.unexpectedContinuationByte, at: i), errorStart: errorStart)
+  }
+
+  public static func surrogateCodePointByte(
+    at i: Int, errorStart: Bool = true
+  ) -> Self {
+    Self(UTF8.ValidationError(.surrogateCodePointByte, at: i), errorStart: errorStart)
+  }
+
+  public static func invalidNonSurrogateCodePointByte(
+    at i: Int, errorStart: Bool = true
+  ) -> Self {
+    Self(UTF8.ValidationError(.invalidNonSurrogateCodePointByte, at: i), errorStart: errorStart)
+  }
+
+  public static func overlongEncodingByte(
+    at i: Int, errorStart: Bool = true
+  ) -> Self {
+    Self(UTF8.ValidationError(.overlongEncodingByte, at: i), errorStart: errorStart)
+  }
+
+  public static func truncatedScalar(
+    _ range: Range<Int>, errorStart: Bool = true
+  ) -> Self {
+    Self(UTF8.ValidationError(.truncatedScalar, range), errorStart: errorStart)
+  }
+}
+
+
+@available(SwiftStdlib 6.2, *)
+private struct ValidationTestCase {
+  var bytes: [UInt8]
+
+  // When fetching all errors, we'll get the error kind given. When
+  // slicing in order to get the next error (e.g.
+  // `UTF8Span.init(validating:))`, we'll get `.unexpectedContinuation`.
+  var errors: [ValidationError]
+
+  var loc: SourceLocStack
+
+  init(
+    _ bytes: [UInt8],
+    file: String = #file,
+    line: UInt = #line,
+    _ errors: [ValidationError]
+  ) {
+    self.bytes = bytes
+    self.errors = errors
+    self.loc = .init(SourceLoc(file, line))
+  }
+
+  func fetchError(
+    at i: Int, wasSliced: Bool
+  ) -> UTF8.ValidationError {
+    let err = errors[i]
+    if wasSliced && !err.errorStart {
+      return .init(.unexpectedContinuationByte, err.error.byteOffsets)
+    }
+    return err.error
+  }
+
+  func expect<T: Equatable>(
+    _ lhs: T,
+    _ rhs: T,
+    file: String = #file,
+    line: UInt = #line
+  ) {
+    expectEqual(
+      lhs,
+      rhs,
+      stackTrace: loc.withCurrentLoc(file: file, line: line))
+  }
+  func fail(
+    _ message: String,
+    file: String = #file,
+    line: UInt = #line
+  ) {
+    expectationFailure(
+      message,
+      trace: "",
+      stackTrace: loc.with(.init(file, line)))
+  }
+
+  /// Test UTF8._checkAllErrors(), which matches directly against
+  /// the provided expected-errors.
+  func testAllErrors() {
+    let caughtErrors = Array(UTF8._checkAllErrors(bytes))
+    for i in 0..<Swift.min(caughtErrors.count, errors.count) {
+      expect(fetchError(at: i, wasSliced: false), caughtErrors[i])
+    }
+    expect(caughtErrors.count, errors.count)
+  }
+
+  /// Test UTF8Span validation. Surface subsequent errors by slicing the
+  /// input (which will convert the error-kind to .unexpectedContinuationByte)
+  func testSpanSlicedErrors() {
+    bytes.withSpan { span in
+      if errors.isEmpty {
+        do throws(UTF8.ValidationError) {
+          // No errors expected
+          _ = try UTF8Span(validating: span)
+        } catch {
+          fail("Unexpected error: \(error)")
+        }
+        return
+      }
+
+      // Check every error, by slicing (which will change error classification
+      // of continuation bytes in multi-byte errors to .unexpectedContinuation)
+      var currentPos = 0
+      var errorIdx = 0
+      while true {
+        do throws(UTF8.ValidationError) {
+          // print("extracting \(currentPos)")
+          _ = try UTF8Span(validating: span._extracting(currentPos...))
+
+          if errorIdx != errors.endIndex {
+            fail("Expected a thrown UTF-8 encoding error")
+          }
+          break
+        } catch {
+          guard errorIdx < errors.endIndex else {
+            fail("Found unexpected subsequent error \(error)")
+            break
+          }
+
+          let expectedError = fetchError(at: errorIdx, wasSliced: true)
+          // print(currentPos)
+          // print(error)
+
+          // print(error.byteOffsets._offset(by: currentPos))
+
+
+          let adjustedErr = UTF8.ValidationError(
+            error.kind,
+            error.byteOffsets._offset(by: currentPos)
+          )
+          expect(expectedError, adjustedErr)
+
+          currentPos = adjustedErr.byteOffsets.upperBound
+          errorIdx += 1
+        }
+
+      }
+
+      // Rest of input should be error-free
+      if let start = errors.last?.error.byteOffsets.upperBound,
+          start < bytes.count
+      {
+        do throws(UTF8.ValidationError) {
+          _ = try UTF8Span(validating: span._extracting(start...))
+        } catch {
+          fail("Found subsequent error \(error)")
+        }
+      }
+    }
+  }
+
+  func run() {
+    testSpanSlicedErrors()
+    testAllErrors()
+  }
+}
+
+if #available(SwiftStdlib 6.2, *) {
+  suite.test("UTF8Span/encoding errors") {
+    func test(
+      _ bytes: Array<UInt8>,
+      _ file: String = #file, line: UInt = #line,
+      _ errors: ValidationError...
+    ) {
+      ValidationTestCase(
+        bytes, file: file, line: line, errors
+      ).run()
+    }
+
+    // Valid string
+    // test(Array("abcde\u{301}f😀🇺🇸🧟‍♀️🧟‍♀️".utf8), [])
+
+    // Bad URL
+    // test(
+    //   Array("http://servername/scripts/..".utf8)
+    //   + [0xC0, 0xAF]
+    //   + Array("../winnt/system32/cmd.exe".utf8),
+    //   [.overlongEncodingByte(at: 28),                    // C0
+    //    .overlongEncodingByte(at: 29, errorStart: false), // AF
+    //   ])
+
+    // test(
+    //   [0xC0, 0xAF, 0xE0, 0x80, 0xBF, 0xF0, 0x81, 0x82, 0x41],
+    //   [.overlongEncodingByte(at: 0),                    // C0
+    //    .overlongEncodingByte(at: 1, errorStart: false), // AF
+    //    .overlongEncodingByte(at: 2),                    // E0
+    //    .overlongEncodingByte(at: 3, errorStart: false), // 80
+    //    .overlongEncodingByte(at: 4, errorStart: false), // BF
+    //    .overlongEncodingByte(at: 5),                    // F0
+    //    .overlongEncodingByte(at: 6, errorStart: false), // 81
+    //    .overlongEncodingByte(at: 7, errorStart: false), // 82
+    //   ])
+    // test(
+    //   [0x41, 0xC0, 0xAF, 0x41, 0xF4, 0x80, 0x80, 0x41],
+    //   [.overlongEncodingByte(at: 1),                    // C0
+    //    .overlongEncodingByte(at: 2, errorStart: false), // AF
+    //    .truncatedScalar(4...6),                         // F4 80 80
+    //   ])
+    // test(
+    //   [0xED, 0xAF, 0x41],
+    //   [.surrogateCodePointByte(at: 0),                    // ED
+    //    .surrogateCodePointByte(at: 1, errorStart: false), // AF
+    //   ])
+    // test(
+    //   [0xED, 0xA0, 0x80, 0xED, 0xBF, 0xBF, 0xED, 0xAF, 0x41],
+    //   [.surrogateCodePointByte(at: 0),                    // ED
+    //    .surrogateCodePointByte(at: 1, errorStart: false), // A0
+    //    .surrogateCodePointByte(at: 2, errorStart: false), // 80
+    //    .surrogateCodePointByte(at: 3),                    // ED
+    //    .surrogateCodePointByte(at: 4, errorStart: false), // BF
+    //    .surrogateCodePointByte(at: 5, errorStart: false), // BF
+    //    .surrogateCodePointByte(at: 6),                    // ED
+    //    .surrogateCodePointByte(at: 7, errorStart: false), // AF
+    //   ])
+    // test(
+    //   [0xF4, 0x91, 0x92, 0x93, 0xFF, 0x41, 0x80, 0xBF, 0x42],
+    //   [.invalidNonSurrogateCodePointByte(at: 0),                    // F4
+    //    .invalidNonSurrogateCodePointByte(at: 1, errorStart: false), // 91
+    //    .invalidNonSurrogateCodePointByte(at: 2, errorStart: false), // 92
+    //    .invalidNonSurrogateCodePointByte(at: 3, errorStart: false), // 93
+    //    .invalidNonSurrogateCodePointByte(at: 4),                    // FF
+    //    .unexpectedContinuationByte(at: 6),                          // 80
+    //    .unexpectedContinuationByte(at: 7),                          // BF
+    //   ])
+    // test(
+    //   [0xE1, 0x80, 0xE2, 0xF0, 0x91, 0x92, 0xF1, 0xBF, 0x41],
+    //   [.truncatedScalar(0...1), // E1 80
+    //    .truncatedScalar(2...2), // E2
+    //    .truncatedScalar(3...5), // F0 91 92
+    //    .truncatedScalar(6...7), // F1 BF
+    //   ])
+    // test(
+    //   [0xE0, 0x81, 0x80],
+    //   [.overlongEncodingByte(at: 0), // E0
+    //    .overlongEncodingByte(at: 1, errorStart: false), // 81
+    //    .overlongEncodingByte(at: 2, errorStart: false), // 80
+    //   ])
+  }
+}
diff --git a/test/stdlib/UTF8SpanIteratorTests.swift b/test/stdlib/UTF8SpanIteratorTests.swift
new file mode 100644
index 0000000000000..8b79471470419
--- /dev/null
+++ b/test/stdlib/UTF8SpanIteratorTests.swift
@@ -0,0 +1,279 @@
+// RUN: %target-run-stdlib-swift(-enable-experimental-feature LifetimeDependence) %S/Inputs/
+// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: executable_test
+
+import Swift
+import StdlibUnittest
+
+var suite = TestSuite("UTF8SpanIterator")
+defer { runAllTests() }
+
+@available(SwiftStdlib 6.2, *)
+extension Array {
+  func withSpan<R>(_ f: (Span<Element>) throws -> R) rethrows -> R {
+    try self.withUnsafeBufferPointer {
+      try f(Span(_unsafeElements: $0))
+    }
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  func withSpan<R>(_ f: (Span<UInt8>) throws -> R) rethrows -> R {
+    try self._withUnsafeBufferPointer {
+      try f(Span(_unsafeElements: $0))
+    }
+  }
+}
+
+
+// 
+@available(SwiftStdlib 6.2, *)
+struct ContentEquivalenceTestCase {
+  var str: String
+  var loc: SourceLocStack
+}
+
+@available(SwiftStdlib 6.2, *)
+extension ContentEquivalenceTestCase {
+  func expectStart(
+    _ scalars: inout UTF8Span.UnicodeScalarIterator
+  ) {
+    let firstScalar = str.unicodeScalars.first
+    expectEqual(0, scalars.currentCodeUnitOffset, stackTrace: loc)
+    expectNil(scalars.previous(), stackTrace: loc)
+    expectEqual(firstScalar, scalars.next(), stackTrace: loc)
+    expectEqual(firstScalar, scalars.previous(), stackTrace: loc)
+    expectNil(scalars.previous(), stackTrace: loc)
+  }
+
+  func expectEnd(
+    _ scalars: inout UTF8Span.UnicodeScalarIterator
+  ) {
+    let lastScalar = str.unicodeScalars.last
+    expectEqual(scalars.currentCodeUnitOffset, scalars.codeUnits.count, stackTrace: loc)
+    expectNil(scalars.next(), stackTrace: loc)
+    expectEqual(lastScalar, scalars.previous(), stackTrace: loc)
+    expectEqual(lastScalar, scalars.next(), stackTrace: loc)
+    expectNil(scalars.next(), stackTrace: loc)
+  }
+
+  func expectStart(
+    _ chars: inout UTF8Span.CharacterIterator
+  ) {
+    let firstChar = str.first
+    expectEqual(0, chars.currentCodeUnitOffset, stackTrace: loc)
+    expectNil(chars.previous(), stackTrace: loc)
+    expectEqual(firstChar, chars.next(), stackTrace: loc)
+    expectEqual(firstChar, chars.previous(), stackTrace: loc)
+    expectNil(chars.previous(), stackTrace: loc)
+  }
+
+  func expectEnd(
+    _ chars: inout UTF8Span.CharacterIterator
+  ) {
+    let lastChar = str.last
+    expectEqual(chars.currentCodeUnitOffset, chars.codeUnits.count, stackTrace: loc)
+    expectNil(chars.next(), stackTrace: loc)
+    expectEqual(lastChar, chars.previous(), stackTrace: loc)
+    expectEqual(lastChar, chars.next(), stackTrace: loc)
+    expectNil(chars.next(), stackTrace: loc)
+  }
+
+
+  func withUTF8Span<R>(_ f: (UTF8Span) throws -> R) rethrows -> R {
+    try Array(str.utf8).withSpan { span in 
+      try f(try! UTF8Span(validating: span))
+    }
+  }
+}
+
+@available(SwiftStdlib 6.2, *)
+extension ContentEquivalenceTestCase {
+  func testBytes() {
+    let otherBytes = Array((str+"abc").utf8)
+
+    withUTF8Span { utf8Span in
+      utf8Span._withUnsafeBufferPointer {
+        expectEqualSequence(str.utf8, $0, stackTrace: loc)
+      }
+    }
+
+    // NOTE: There's a slight jarring due to not having the same 
+    // iterators for code units
+  }
+
+  func testScalars() {
+    withUTF8Span { utf8Span in 
+      // Test forwards
+      var utf8SpanIter = utf8Span.makeUnicodeScalarIterator()
+      var stringIter = str.unicodeScalars.makeIterator()
+      while let scalar = utf8SpanIter.next() {
+        expectEqual(scalar, stringIter.next(), stackTrace: loc)
+      }
+      expectNil(stringIter.next(), stackTrace: loc)
+      expectEnd(&utf8SpanIter)
+
+      // Test backwards
+      var stringRevIter = str.unicodeScalars.reversed().makeIterator()
+      while let scalar = utf8SpanIter.previous() {
+        expectEqual(scalar, stringRevIter.next(), stackTrace: loc)
+      }
+      expectNil(stringRevIter.next(), stackTrace: loc)
+      expectStart(&utf8SpanIter)
+
+      let numElements = str.unicodeScalars.count
+      let lastElement = str.unicodeScalars.last
+      let firstElement = str.unicodeScalars.first
+
+      expectEqual(numElements, utf8SpanIter.skipForward(by: Int.max))
+      expectEnd(&utf8SpanIter)
+      expectEqual(numElements, utf8SpanIter.skipBack(by: Int.max))
+      expectStart(&utf8SpanIter)
+      expectEqual(numElements, utf8SpanIter.skipForward(by: numElements))
+      expectEnd(&utf8SpanIter)
+      expectEqual(numElements, utf8SpanIter.skipBack(by: numElements))
+      expectStart(&utf8SpanIter)
+
+      if numElements > 0 {
+        expectStart(&utf8SpanIter)
+        expectEqual(numElements-1, utf8SpanIter.skipForward(by: numElements-1))
+        expectEqual(lastElement, utf8SpanIter.next())
+        expectEnd(&utf8SpanIter)
+
+        expectEqual(numElements-1, utf8SpanIter.skipBack(by: numElements-1))
+        expectEqual(firstElement, utf8SpanIter.previous())
+        expectStart(&utf8SpanIter)
+      }
+
+      // TODO: test reset variants
+      // TODO: test prefix/suffix
+
+    }
+  }
+
+  func testCharacters() {
+    withUTF8Span { utf8Span in 
+      // Test forwards
+      var utf8SpanIter = utf8Span.makeCharacterIterator()
+      var stringIter = str.makeIterator()
+      while let char = utf8SpanIter.next() {
+        expectEqual(char, stringIter.next(), stackTrace: loc)
+      }
+      expectNil(stringIter.next(), stackTrace: loc)
+      expectEnd(&utf8SpanIter)
+
+      // Test backwards
+      var stringRevIter = str.reversed().makeIterator()
+      while let char = utf8SpanIter.previous() {
+        expectEqual(char, stringRevIter.next(), stackTrace: loc)
+      }
+      expectNil(stringRevIter.next(), stackTrace: loc)
+      expectStart(&utf8SpanIter)
+
+      let numElements = str.count
+      let lastElement = str.last
+      let firstElement = str.first
+
+      expectEqual(numElements, utf8SpanIter.skipForward(by: Int.max))
+      expectEnd(&utf8SpanIter)
+      expectEqual(numElements, utf8SpanIter.skipBack(by: Int.max))
+      expectStart(&utf8SpanIter)
+      expectEqual(numElements, utf8SpanIter.skipForward(by: numElements))
+      expectEnd(&utf8SpanIter)
+      expectEqual(numElements, utf8SpanIter.skipBack(by: numElements))
+      expectStart(&utf8SpanIter)
+
+      if numElements > 0 {
+        expectStart(&utf8SpanIter)
+        expectEqual(numElements-1, utf8SpanIter.skipForward(by: numElements-1))
+        expectEqual(lastElement, utf8SpanIter.next())
+        expectEnd(&utf8SpanIter)
+
+        expectEqual(numElements-1, utf8SpanIter.skipBack(by: numElements-1))
+        expectEqual(firstElement, utf8SpanIter.previous())
+        expectStart(&utf8SpanIter)
+      }
+
+      // TODO: test reset variants
+      // TODO: test prefix/suffix
+    }
+  }
+
+  func run() {
+    testBytes()
+    testScalars()
+    testCharacters()
+
+    // TODO: test grapheme break iterator
+  }
+
+}
+
+if #available(SwiftStdlib 6.2, *) {
+  suite.test("UTF8Span/iterators") {
+    func test(
+      _ s: String,
+      file: String = #file,
+      line: UInt = #line
+    ) {
+      // print("testing: \(s)")
+      let t = ContentEquivalenceTestCase(
+        str: s, loc: .init(SourceLoc(file, line)))
+      t.run()
+    }
+
+    test("")
+    test("a")
+    test("á")
+    test("a\u{301}")
+    test("🧟‍♀️")
+    test("abc")
+    test("abcde\u{301}")
+    test("abéÏ𓀀")
+    test("012345678901234567890")
+    test("abéÏ012345678901234567890𓀀")
+    test("😀😃🤢🤮👩🏿‍🎤🧛🏻‍♂️🧛🏻‍♂️👩‍👩‍👦‍👦")
+    test("defghijklmnopqrstuvwxyz")
+    test("ab🧟‍♀️de\u{301}bytés")
+    test("ab🧟‍♀️de\u{301}🧟‍♀️")
+    test("ab🧟‍♀️de🧟‍♀️\u{301}")
+  }
+}
+
+// @available(SwiftStdlib 6.2, *)
+// extension UTF8Span {
+//   func splitOffASCIIPrefix() -> (UTF8Span, UTF8Span) {
+//     if isKnownASCII {
+//       return (self, .init())
+//     }
+//     var splitPoint = 0
+//     while splitPoint < codeUnits.count && codeUnits[unchecked: split] < 0x80 {
+//       splitPoint += 1
+//     }
+
+//   }
+// }
+
+if #available(SwiftStdlib 6.2, *) {
+  suite.test("UTF8Span/whatever") {
+    // var badURLBytes: [UInt8] = []
+    // badURLBytes.append(contentsOf: "http://servername/scripts/..".utf8)
+
+    // // Invalid overlong encoding of "/"
+    // badURLBytes.append(contentsOf: [0xC0, 0xAF])
+
+    // badURLBytes.append(contentsOf: "../winnt/system32/cmd.exe".utf8)
+
+    // // try! UTF8Span(validating: badURLBytes.span)
+
+    // badURLBytes.withSpan {
+    //   try! UTF8Span(validating: $0)
+    // }
+
+
+
+  }
+}
+
+
diff --git a/test/stdlib/UTF8SpanQueriesComparisons.swift b/test/stdlib/UTF8SpanQueriesComparisons.swift
new file mode 100644
index 0000000000000..b37bfbc2024eb
--- /dev/null
+++ b/test/stdlib/UTF8SpanQueriesComparisons.swift
@@ -0,0 +1,278 @@
+// RUN: %target-run-stdlib-swift %S/Inputs/
+
+// REQUIRES: executable_test
+
+import Swift
+import StdlibUnittest
+
+@available(SwiftStdlib 6.2, *)
+extension UTF8Span {
+  static func ~=(_ lhs: StaticString, _ rhs: UTF8Span) -> Bool {
+    return lhs.withUTF8Buffer { str in
+      rhs._withUnsafeBufferPointer { span in
+        str.elementsEqual(span)
+      }
+    }
+  }
+}
+
+var suite = TestSuite("UTF8SpanQueriesComparisons")
+defer { runAllTests() }
+
+@available(SwiftStdlib 6.2, *)
+extension Array where Element == UInt8 {
+  func withSpan<R>(_ f: (Span<Element>) throws -> R) rethrows -> R {
+    try self.withUnsafeBufferPointer {
+      try f(Span(_unsafeElements: $0))
+    }
+  }
+  func withUTF8Span<R>(_ f: (UTF8Span) throws -> R) rethrows -> R {
+    try self.withSpan { span in
+      try f(try! UTF8Span(validating: span))
+    }
+  }
+}
+
+if #available(SwiftStdlib 6.2, *) {
+  suite.test("UTF8Span/tilde equals") {
+    Array("abcdefg".utf8).withUTF8Span { utf8Span in
+      switch utf8Span {
+      case "def":
+        expectationFailure(
+          "unexpected pattern match",
+          trace: "",
+          stackTrace: SourceLocStack().withCurrentLoc())
+      case "abcdef":
+        expectationFailure(
+          "unexpected pattern match",
+          trace: "",
+          stackTrace: SourceLocStack().withCurrentLoc())
+      case "abcdefg ":
+        expectationFailure(
+          "unexpected pattern match",
+          trace: "",
+          stackTrace: SourceLocStack().withCurrentLoc())
+      case "abcdefg\0":
+        expectationFailure(
+          "unexpected pattern match",
+          trace: "",
+          stackTrace: SourceLocStack().withCurrentLoc())
+      case "abcdefg":
+        break
+      default:
+        expectationFailure(
+          "expected a pattern match",
+          trace: "",
+          stackTrace: SourceLocStack().withCurrentLoc())
+      }
+    }
+  }
+
+  suite.test("UTF8Span/Sequence equal") {
+    // // A string and its canonical equivalent
+    // let testCases: [(String, String?)] = [
+    //   ("abdefg", nil)
+    //   ("café", "cafe\u{301}")
+    // ]
+  }
+
+  suite.test("UTF8Span/isKnownASCII") {
+    let tests: [(String, Bool)] = [
+      ("abc", true),
+      ("abcdefghil1235@#% _/.sladfj234 ", true),
+      ("abcdefghil1\u{80}sladfj234 ", false),
+    ]
+
+    for (test, expected) in tests {
+      Array(test.utf8).withUTF8Span {
+        expectEqual(expected, $0.isKnownASCII)
+      }
+    }
+  }
+
+  suite.test("UTF8Span/isKnownNFC") {
+    enum Normalness {
+      case known
+      case quickCheck
+      case fullCheck
+      case notNFC
+    }
+
+    let nfcQCNo = "\u{0374}"
+    let nfcQCYes = "\u{0374}"
+
+    let tests: [(String, Normalness)] = [
+      ("abc", .known),
+      ("abcdefghil123567890", .known),
+      ("abcdefghil1\u{299}123345678 ", .quickCheck),
+      ("abc日曜日xyz", .quickCheck),
+      ("abcde日曜日\u{301}", .fullCheck),
+      ("abcde\u{301}fghijkl", .notNFC),
+    ]
+
+    for (test, expected) in tests {
+      Array(test.utf8).withUTF8Span {
+        var span = $0
+        if span.isKnownNFC {
+          expectEqual(expected, .known)
+        } else if span.checkForNFC(quickCheck: true) {
+          expectEqual(expected, .quickCheck)
+        } else if span.checkForNFC(quickCheck: false) {
+          expectEqual(expected, .fullCheck)
+        } else {
+          expectEqual(expected, .notNFC)
+        }
+      }
+    }
+  }
+
+  suite.test("UTF8Span/canonical equivalence") {
+
+    // TODO: refactor to be test-case declaration driven, and add more tests...
+    //   `(normalized: String, variants: [String], lessThan: String, greaterThan: String)`
+
+    let precomposedStr = "café"
+    let decomposedStr = "cafe\u{301}"
+
+    let precomposed = Array(precomposedStr.utf8)
+    let decomposed = Array(decomposedStr.utf8)
+
+    precomposed.withSpan { pre in
+      let utf8Precomposed = try! UTF8Span(validating: pre)
+      decomposed.withSpan { de in
+        let utf8Decomposed = try! UTF8Span(validating: de)
+
+        // print("scalars for \(precomposedStr.unicodeScalars)")
+        // var preScalars = utf8Precomposed.makeUnicodeScalarIterator()
+        // while let s = preScalars.next() {
+        //   print(s)
+        // }
+
+        // print("scalars for \(decomposedStr.unicodeScalars)")
+        // var deScalars = utf8Decomposed.makeUnicodeScalarIterator()
+        // while let s = deScalars.next() {
+        //   print(s)
+        // }
+        
+        expectTrue(utf8Precomposed.isCanonicallyEquivalent(to: utf8Decomposed))
+
+        expectTrue(utf8Precomposed.bytesEqual(to: precomposedStr.utf8))
+        expectFalse(utf8Precomposed.bytesEqual(to: decomposedStr.utf8))
+
+        expectTrue(utf8Decomposed.bytesEqual(to: decomposedStr.utf8))
+        expectFalse(utf8Decomposed.bytesEqual(to: precomposedStr.utf8))
+
+        expectTrue(utf8Precomposed.unicodeScalarsEqual(to: precomposedStr.unicodeScalars))
+        expectFalse(utf8Precomposed.unicodeScalarsEqual(to: decomposedStr.unicodeScalars))
+
+        expectTrue(utf8Decomposed.unicodeScalarsEqual(to: decomposedStr.unicodeScalars))
+        expectFalse(utf8Decomposed.unicodeScalarsEqual(to: precomposedStr.unicodeScalars))
+
+        expectTrue(utf8Precomposed.charactersEqual(to: precomposedStr))
+        expectTrue(utf8Precomposed.charactersEqual(to: decomposedStr))
+
+        expectTrue(utf8Decomposed.charactersEqual(to: decomposedStr))
+        expectTrue(utf8Decomposed.charactersEqual(to: precomposedStr))
+
+        // Equivalence means no-one is less than the other
+        expectFalse(utf8Decomposed.isCanonicallyLessThan(utf8Precomposed))
+        expectFalse(utf8Precomposed.isCanonicallyLessThan(utf8Decomposed))
+
+      }
+
+    }
+
+
+  }
+
+
+}
+
+// TODO: Rest of this file is in-progress TODOs
+
+
+/*
+
+
+isASCII
+isKnownNFC
+checkForNFC(quickCheck:)
+isKnownSingleScalarCharacters
+checkForSingleScalarCharacters(quickCheck:)
+
+public func bytesEqual(to other: UTF8Span) -> Bool
+public func bytesEqual(to other: some Sequence<UInt8>) -> Bool
+
+public func scalarsEqual(
+  to other: some Sequence<Unicode.Scalar>
+) -> Bool
+
+public func charactersEqual(
+  to other: some Sequence<Character>
+) -> Bool
+
+public func isCanonicallyEquivalent(
+  to other: UTF8Span
+) -> Bool
+
+public func isCanonicallyLessThan(
+  _ other: UTF8Span
+) -> Bool
+
+*/
+
+// @available(SwiftStdlib 6.2, *)
+// private struct QueryTestCase {
+//   var content: String
+
+//   var loc: SourceLocStack
+
+//   var isASCII: Bool
+
+//   // TODO: This might become API, or otherwise calculated at init time
+//   var isLatinyNFC: Bool {
+//     bytes.allSatisfy { $0 < 0xCC }
+//   }
+
+//   var isQuickNFC: Bool
+//   var isNFC: Bool
+
+//   var isQuickSSC: Bool
+//   var isSSC: Bool
+// }
+
+// if #available(SwiftStdlib 6.2, *) {
+//   suite.test("UTF8Span/queries") {
+//   }
+// }
+
+// enum ComparisonResult {
+//   binaryEqual
+//   canonicallyEqual
+//   canonicallyLess
+//   inequal
+// }
+
+// private struct ComparisonTestCase {
+//   var content: String
+//   var comparisons: [(String, ComparisonResult)]
+
+//   var loc: SourceLocStack
+// }
+
+// if #available(SwiftStdlib 6.2, *) {
+//   suite.test("UTF8Span/comparisons") {
+//     func test()
+//   }
+// }
+
+
+/*
+
+  input string, to check the bits and relevant info
+  comparison string and expected comparison level
+
+*/
+
+
+// }
\ No newline at end of file
diff --git a/test/stdlib/UnavailableStringAPIs.swift.gyb b/test/stdlib/UnavailableStringAPIs.swift.gyb
index 30fe07b37cb80..d4984a2701ffb 100644
--- a/test/stdlib/UnavailableStringAPIs.swift.gyb
+++ b/test/stdlib/UnavailableStringAPIs.swift.gyb
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %gyb -D_runtime=%target-runtime %s -o %t/main.swift
-// RUN: %line-directive %t/main.swift -- %target-swift-frontend -typecheck -verify %t/main.swift
+// RUN: %line-directive %t/main.swift -- %target-swift-frontend -typecheck -verify -verify-ignore-unrelated %t/main.swift
 
 func test_StringSubscriptByInt(
   x: String,
diff --git a/test/stdlib/UnicodeScalarDiagnostics.swift b/test/stdlib/UnicodeScalarDiagnostics.swift
index 863fdde2ae5da..ca5c452563977 100644
--- a/test/stdlib/UnicodeScalarDiagnostics.swift
+++ b/test/stdlib/UnicodeScalarDiagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // FIXME: The clarity of these diagnostics could be improved.
 // <rdar://problem/29912193>
diff --git a/test/stdlib/UnsafePointerDiagnostics.swift b/test/stdlib/UnsafePointerDiagnostics.swift
index 0a3cbf8ba9800..53c5bffece4e2 100644
--- a/test/stdlib/UnsafePointerDiagnostics.swift
+++ b/test/stdlib/UnsafePointerDiagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-invalid-ephemeralness-as-error -disable-objc-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-invalid-ephemeralness-as-error -disable-objc-interop
 
 // Test availability attributes on UnsafePointer initializers.
 // Assume the original source contains no UnsafeRawPointer types.
@@ -78,7 +78,7 @@ func unsafePointerConversionAvailability(
 
   _ = UnsafeMutablePointer<Int>(rp) // expected-error {{cannot convert value of type 'UnsafeRawPointer' to expected argument type 'UnsafeMutablePointer<Int>'}}
   _ = UnsafeMutablePointer<Int>(mrp) // expected-error {{cannot convert value of type 'UnsafeMutableRawPointer' to expected argument type 'UnsafeMutablePointer<Int>'}}
-  // Two candidates here: OpaquePointer? and UnsafeMutablePointer<Int>?
+  // This is ambiguous because we have failable and non-failable initializers that accept the same argument type.
   _ = UnsafeMutablePointer<Int>(orp) // expected-error {{no exact matches in call to initializer}}
   // Two candidates here: OpaquePointer? and UnsafeMutablePointer<Int>?
   _ = UnsafeMutablePointer<Int>(omrp) // expected-error {{no exact matches in call to initializer}}
@@ -87,7 +87,6 @@ func unsafePointerConversionAvailability(
   _ = UnsafePointer<Int>(mrp) // expected-error {{cannot convert value of type 'UnsafeMutableRawPointer' to expected argument type 'UnsafePointer<Int>'}}
   // Two candidates here: OpaquePointer? and UnsafeMutablePointer<Int>?
   _ = UnsafePointer<Int>(orp)  // expected-error {{no exact matches in call to initializer}}
-  // Two candidates here: OpaquePointer? and UnsafeMutablePointer<Int>?
   _ = UnsafePointer<Int>(omrp) // expected-error {{no exact matches in call to initializer}}
 
   _ = UnsafePointer<Int>(ups) // expected-error {{cannot convert value of type 'UnsafePointer<String>' to expected argument type 'UnsafePointer<Int>'}}
@@ -126,6 +125,7 @@ func unsafeRawBufferPointerConversions(
   _ = UnsafeMutableRawBufferPointer(start: omrp, count: 1)
   _ = UnsafeRawBufferPointer(start: omrp, count: 1)
   _ = UnsafeMutableRawBufferPointer(start: orp, count: 1) // expected-error {{cannot convert value of type 'UnsafeRawPointer?' to expected argument type 'UnsafeMutableRawPointer?'}}
+  // expected-note@-1 {{arguments to generic parameter 'Wrapped' ('UnsafeRawPointer' and 'UnsafeMutableRawPointer') are expected to be equal}}
   _ = UnsafeRawBufferPointer(start: orp, count: 1)
 }
 
diff --git a/test/stdlib/UnsafePointerDiagnostics_warning.swift b/test/stdlib/UnsafePointerDiagnostics_warning.swift
index 108be85487ec1..9e5d9a0d50cc6 100644
--- a/test/stdlib/UnsafePointerDiagnostics_warning.swift
+++ b/test/stdlib/UnsafePointerDiagnostics_warning.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -disable-objc-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-objc-interop
 
 // Test that we get a custom diagnostic for an ephemeral conversion to non-ephemeral param for an Unsafe[Mutable][Raw][Buffer]Pointer init.
 func unsafePointerInitEphemeralConversions() {
diff --git a/test/stdlib/VarArgs.swift b/test/stdlib/VarArgs.swift
index bb1af50f63a47..2f429faa88fbb 100644
--- a/test/stdlib/VarArgs.swift
+++ b/test/stdlib/VarArgs.swift
@@ -174,7 +174,7 @@ test_varArgs6()
 
 func test_varArgs7() {
 #if canImport(Darwin) && arch(arm64)
-  let canTest = if #available(SwiftStdlib 6.2, *) { false } else { true }
+  let canTest = if #available(SwiftStdlib 6.2, *) { true } else { false }
 #else
   // va_list is more complicated on other targets so that behavior is not the
   // same, skip the test by doing a fake print of the expected output. Also
@@ -193,6 +193,25 @@ func test_varArgs7() {
 }
 test_varArgs7()
 
+func test_varArgs8() {
+  // Check with vsnprintf as well just in case to make sure it works with C APIs
+  // imported from actual libc headers. Why checks with vprintf above are not enough?
+  // ClangImporter respects the vprintf interface re-defined in LibcShims.h but it could
+  // be slightly different than the one in platform libc on some platforms, including WASI.
+  // (e.g. wasi-libc defines `int vprintf(const char *__restrict, __isoc_va_list);` where
+  // `__isoc_va_list` is `typedef __builtin_va_list __isoc_va_list;`, but LibcShims.h aliases
+  // __builtin_va_list as `va_list`.)
+  // https://github.com/swiftlang/swift/issues/72398
+  let string = withUnsafeTemporaryAllocation(of: CChar.self, capacity: 512) { buffer in
+    withVaList([CInt(123)]) { args in
+      _ = vsnprintf(buffer.baseAddress!, buffer.count, "%d", args)
+    }
+    return String(cString: buffer.baseAddress!)
+  }
+  print(string)
+  // CHECK: 123
+}
+test_varArgs8()
 
 // CHECK: done.
 my_printf("done.")
diff --git a/test/stdlib/WASILibcAPI.swift b/test/stdlib/WASILibcAPI.swift
index fe599bb9f3878..718444077de0d 100644
--- a/test/stdlib/WASILibcAPI.swift
+++ b/test/stdlib/WASILibcAPI.swift
@@ -1,6 +1,6 @@
 // RUN: %target-swift-frontend -typecheck -swift-version 6 %s -verify
 // REQUIRES: executable_test
-// REQUIRES: OS=wasi
+// REQUIRES: OS=wasip1
 
 import WASILibc
 
diff --git a/test/stdlib/WeakMirror.swift b/test/stdlib/WeakMirror.swift
index 02ad4ab150d7f..baefe1451b718 100644
--- a/test/stdlib/WeakMirror.swift
+++ b/test/stdlib/WeakMirror.swift
@@ -14,9 +14,9 @@
 // RUN: if [ %target-runtime == "objc" ]; \
 // RUN: then \
 // RUN:   %target-clang %S/Inputs/Mirror/Mirror.mm -c -o %t/Mirror.mm.o -g && \
-// RUN:   %target-build-swift -Xfrontend -disable-access-control %s -I %S/Inputs/Mirror/ -Xlinker %t/Mirror.mm.o -o %t/Mirror; \
+// RUN:   %target-build-swift -Xfrontend -disable-access-control -Xfrontend -enable-experimental-feature -Xfrontend ImmutableWeakCaptures %s -I %S/Inputs/Mirror/ -Xlinker %t/Mirror.mm.o -o %t/Mirror; \
 // RUN: else \
-// RUN:   %target-build-swift %s -Xfrontend -disable-access-control -o %t/Mirror; \
+// RUN:   %target-build-swift %s -Xfrontend -disable-access-control -Xfrontend -enable-experimental-feature -Xfrontend ImmutableWeakCaptures -o %t/Mirror; \
 // RUN: fi
 // RUN: %target-codesign %t/Mirror
 // RUN: %target-run %t/Mirror
@@ -24,6 +24,7 @@
 // REQUIRES: executable_test
 // REQUIRES: shell
 // REQUIRES: reflection
+// REQUIRES: swift_feature_ImmutableWeakCaptures
 
 import StdlibUnittest
 
@@ -123,6 +124,89 @@ mirrors.test("class/NativeSwiftClassHasNativeWeakReferenceNoLeak") {
   expectNil(verifier)
 }
 
+class NativeSwiftClassHasWeakLet {
+  weak let weakProperty: AnyObject?
+  let x: Int
+  init(x: Int, weakProperty: AnyObject?) {
+    self.x = x
+    self.weakProperty = weakProperty
+  }
+}
+
+class NativeSwiftClassHasNativeClassBoundExistentialLet {
+  weak let weakProperty: NativeClassBoundExistential?
+  let x: Int
+  init(x: Int, weakProperty: NativeClassBoundExistential?) {
+    self.x = x
+    self.weakProperty = weakProperty
+  }
+}
+
+struct StructHasNativeWeakLetReference {
+  weak let weakProperty: AnyObject?
+  let x: Int
+  init(x: Int, weakProperty: AnyObject?) {
+    self.x = x
+    self.weakProperty = weakProperty
+  }
+}
+
+mirrors.test("class/NativeSwiftClassHasNativeWeakLetReference") {
+  let child = NativeSwiftClass(x: 2020)
+  let parent = NativeSwiftClassHasWeakLet(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! NativeSwiftClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+mirrors.test("class/NativeSwiftClassHasNativeClassBoundExistentialLet") {
+  let child = NativeSwiftClass(x: 2020) as NativeClassBoundExistential
+  let parent = NativeSwiftClassHasNativeClassBoundExistentialLet(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! NativeSwiftClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+mirrors.test("struct/StructHasNativeWeakLetReference") {
+  let child = NativeSwiftClass(x: 2020)
+  var parent = StructHasNativeWeakLetReference(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! NativeSwiftClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+// https://github.com/apple/swift/issues/51384
+// Using 'Mirror' to access a weak reference results in object being
+// retained indefinitely
+mirrors.test("class/NativeSwiftClassHasNativeWeakLetReferenceNoLeak") {
+  weak var verifier: AnyObject?
+  do {
+    let child = NativeSwiftClass(x: 2020)
+    verifier = child
+    let parent = NativeSwiftClassHasWeakLet(x: 1010, weakProperty: child)
+    let mirror = Mirror(reflecting: parent)
+    let children = Array(mirror.children)
+    let extractedChild = children[0].1 as! NativeSwiftClass
+    expectNotNil(extractedChild)
+    expectNotNil(verifier)
+    // If child is destroyed, the above cast and checks will fail.
+    _fixLifetime(child)
+  }
+  expectNil(verifier)
+}
+
 #if _runtime(_ObjC)
 
 import Foundation
@@ -292,6 +376,156 @@ mirrors.test("struct/StructHasObjCClassBoundExistential") {
   print(extractedChild)
 }
 
+class NativeSwiftClassHasObjCClassBoundExistentialLet {
+  weak let weakProperty: ObjCClassExistential?
+  let x: Int
+  init(x: Int, weakProperty: ObjCClassExistential?) {
+    self.x = x
+    self.weakProperty = weakProperty
+  }
+}
+
+class ObjCClassHasWeakLet : NSObject {
+  weak let weakProperty: AnyObject?
+  let x: Int
+  init(x: Int, weakProperty: AnyObject?) {
+    self.x = x
+    self.weakProperty = weakProperty
+  }
+}
+
+class ObjCClassHasNativeClassBoundExistentialLet : NSObject {
+  weak let weakProperty: NativeClassBoundExistential?
+  let x: Int
+  init(x: Int, weakProperty: NativeClassBoundExistential?) {
+    self.x = x
+    self.weakProperty = weakProperty
+  }
+}
+
+class ObjCClassHasObjCClassBoundExistentialLet : NSObject {
+  weak let weakProperty: ObjCClassExistential?
+  let x: Int
+  init(x: Int, weakProperty: ObjCClassExistential?) {
+    self.x = x
+    self.weakProperty = weakProperty
+  }
+}
+
+struct StructHasObjCWeakLetReference {
+  weak let weakProperty: ObjCClass?
+  let x: Int
+  init(x: Int, weakProperty: ObjCClass?) {
+    self.x = x
+    self.weakProperty = weakProperty
+  }
+}
+
+struct StructHasObjCClassBoundExistentialLet {
+  weak let weakProperty: ObjCClassExistential?
+  let x: Int
+  init(x: Int, weakProperty: ObjCClassExistential?) {
+    self.x = x
+    self.weakProperty = weakProperty
+  }
+}
+
+mirrors.test("class/NativeSwiftClassHasObjCWeakLetReference") {
+  let child = ObjCClass(x: 2020)
+  let parent = NativeSwiftClassHasWeakLet(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! ObjCClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+mirrors.test("class/NativeSwiftClassHasObjCClassBoundExistentialLet") {
+  let child = ObjCClass(x: 2020) as ObjCClassExistential
+  let parent = NativeSwiftClassHasObjCClassBoundExistentialLet(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! ObjCClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+mirrors.test("class/ObjCClassHasNativeWeakLet") {
+  let child = NativeSwiftClass(x: 2020)
+  let parent = ObjCClassHasWeakLet(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! NativeSwiftClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+mirrors.test("class/ObjcCClassHasObjCWeakLetReference") {
+  let child = ObjCClass(x: 2020)
+  let parent = ObjCClassHasWeakLet(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! ObjCClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+mirrors.test("class/ObjCClassHasNativeClassBoundExistentialLet") {
+  let child = NativeSwiftClass(x: 2020) as NativeClassBoundExistential
+  let parent = ObjCClassHasNativeClassBoundExistentialLet(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! NativeSwiftClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+mirrors.test("class/ObjCClassHasObjCClassBoundExistentialLet") {
+  let child = ObjCClass(x: 2020) as ObjCClassExistential
+  let parent = ObjCClassHasObjCClassBoundExistentialLet(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! ObjCClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+mirrors.test("struct/StructHasObjCWeakLetReference") {
+  let child = ObjCClass(x: 2020)
+  var parent = StructHasObjCWeakLetReference(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! ObjCClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
+mirrors.test("struct/StructHasObjCClassBoundExistentialLet") {
+  let child = ObjCClass(x: 2020) as ObjCClassExistential
+  var parent = StructHasObjCClassBoundExistentialLet(x: 1010, weakProperty: child)
+  let mirror = Mirror(reflecting: parent)
+  let children = Array(mirror.children)
+  let extractedChild = children[0].1 as! ObjCClass
+  expectNotEqual(parent.x, extractedChild.x)
+  expectEqual(ObjectIdentifier(child), ObjectIdentifier(extractedChild))
+  expectEqual(child.x, extractedChild.x)
+  print(extractedChild)
+}
+
 #endif
 
 runAllTests()
diff --git a/test/stdlib/WinSDK_GUID.swift b/test/stdlib/WinSDK_GUID.swift
new file mode 100644
index 0000000000000..631888157003f
--- /dev/null
+++ b/test/stdlib/WinSDK_GUID.swift
@@ -0,0 +1,9 @@
+// RUN: %target-build-swift %s
+// REQUIRES: OS=windows-msvc
+
+// Make sure that importing WinSDK brings in the GUID type, which is declared in
+// /shared and not in /um.
+
+import WinSDK
+
+public func usesGUID(_ x: GUID) {}
diff --git a/test/stdlib/mmap.swift b/test/stdlib/mmap.swift
index 2695875543911..c5179cbed04b5 100644
--- a/test/stdlib/mmap.swift
+++ b/test/stdlib/mmap.swift
@@ -1,7 +1,7 @@
 // RUN: %target-run-simple-swift %t
 // REQUIRES: executable_test
 // UNSUPPORTED: OS=windows-msvc
-// UNSUPPORTED: OS=wasi
+// UNSUPPORTED: OS=wasip1
 
 import StdlibUnittest
 #if canImport(Darwin)
diff --git a/test/stdlib/simd_diagnostics.swift b/test/stdlib/simd_diagnostics.swift
index f30d278c0cb4f..d6e2c12fa9f0a 100644
--- a/test/stdlib/simd_diagnostics.swift
+++ b/test/stdlib/simd_diagnostics.swift
@@ -1,8 +1,8 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // FIXME: No simd module on linux rdar://problem/20795411
-// XFAIL: OS=linux-gnu, OS=windows-msvc, OS=openbsd, OS=linux-android, OS=linux-androideabi
-// XFAIL: OS=wasi
+// XFAIL: OS=linux-gnu, OS=windows-msvc, OS=openbsd, OS=linux-android, OS=linux-androideabi, OS=freebsd
+// XFAIL: CPU=wasm32
 
 import simd
 
diff --git a/test/stdlib/symbol-visibility-linux.test-sh b/test/stdlib/symbol-visibility-linux.test-sh
index 69345c00d5c61..4898454f660ae 100644
--- a/test/stdlib/symbol-visibility-linux.test-sh
+++ b/test/stdlib/symbol-visibility-linux.test-sh
@@ -257,6 +257,14 @@
 // RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE15_M_replace_coldEPcmPKcmm \
 // RUN:             -e _ZSt12__str_concatINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEET_PKNS6_10value_typeENS6_9size_typeES9_SA_RKNS6_14allocator_typeE \
 // RUN:             -e _ZNSt7__cxx119to_stringEl \
+// RUN:             -e _ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE17_M_realloc_appendIJS5_EEEvDpOT_ \
+// RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE22__resize_and_overwriteIZNS_9to_stringEiEUlPcmE_EEvmT_ \
+// RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE22__resize_and_overwriteIZNS_9to_stringEjEUlPcmE_EEvmT_ \
+// RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE22__resize_and_overwriteIZNS_9to_stringEmEUlPcmE_EEvmT_ \
+// RUN:             -e _ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE17_M_realloc_appendIJRKS5_EEEvDpOT_ \
+// RUN:             -e _ZNSt6vectorISt10unique_ptrIKvSt8functionIFvPS1_EEESaIS6_EE17_M_realloc_appendIJS6_EEEvDpOT_ \
+// RUN:             -e _ZNSt6vectorISt8optionalISt4pairINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEbEESaIS9_EE17_M_realloc_appendIJRKS9_EEEvDpOT_ \
+// RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE22__resize_and_overwriteIZNS_9to_stringElEUlPcmE_EEvmT_ \
 // RUN:   > %t/swiftCore-all.txt
 // RUN: %llvm-nm --defined-only --extern-only --no-weak %platform-dylib-dir/%target-library-name(swiftCore) > %t/swiftCore-no-weak.txt
 // RUN: diff -u %t/swiftCore-all.txt %t/swiftCore-no-weak.txt
@@ -270,6 +278,7 @@
 // RUN:             -e _ZNSt6vectorISsSaISsEE17_M_realloc_insertIJSsEEEvN9__gnu_cxx17__normal_iteratorIPSsS1_EEDpOT_ \
 // RUN:             -e _ZNSt6vectorISt10unique_ptrIKvSt8functionIFvPS1_EEESaIS6_EE19_M_emplace_back_auxIJS6_EEEvDpOT_ \
 // RUN:             -e _ZNSt6vectorISt10unique_ptrIKvSt8functionIFvPS1_EEESaIS6_EE17_M_realloc_insertIJS6_EEEvN9__gnu_cxx17__normal_iteratorIPS6_S8_EEDpOT_ \
+// RUN:             -e _ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE17_M_realloc_insertIJRKS5_EEEvN9__gnu_cxx17__normal_iteratorIPS5_S7_EEDpOT_ \
 // RUN:             -e _ZNSt10_HashtableImSt4pairIKmSt10unique_ptrIKvSt8functionIFvPS3_EEEESaIS9_ENSt8__detail10_Select1stESt8equal_toImESt4hashImENSB_18_Mod_range_hashingENSB_20_Default_ranged_hashENSB_20_Prime_rehash_policyENSB_17_Hashtable_traitsILb0ELb0ELb1EEEE10_M_emplaceIJS0_ImS8_EEEES0_INSB_14_Node_iteratorIS9_Lb0ELb0EEEbESt17integral_constantIbLb1EEDpOT_ \
 // RUN:             -e _ZNSt10_HashtableImSt4pairIKmSt10unique_ptrIKvSt8functionIFvPS3_EEEESaIS9_ENSt8__detail10_Select1stESt8equal_toImESt4hashImENSB_18_Mod_range_hashingENSB_20_Default_ranged_hashENSB_20_Prime_rehash_policyENSB_17_Hashtable_traitsILb0ELb0ELb1EEEE13_M_rehash_auxEmSt17integral_constantIbLb1EE \
 // RUN:             -e _ZNSt10_HashtableImSt4pairIKmSt10unique_ptrIKvSt8functionIFvPS3_EEEESaIS9_ENSt8__detail10_Select1stESt8equal_toImESt4hashImENSB_18_Mod_range_hashingENSB_20_Default_ranged_hashENSB_20_Prime_rehash_policyENSB_17_Hashtable_traitsILb0ELb0ELb1EEEED2Ev \
@@ -518,6 +527,14 @@
 // RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE15_M_replace_coldEPcmPKcmm \
 // RUN:             -e _ZSt12__str_concatINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEET_PKNS6_10value_typeENS6_9size_typeES9_SA_RKNS6_14allocator_typeE \
 // RUN:             -e _ZNSt7__cxx119to_stringEl \
+// RUN:             -e _ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE17_M_realloc_appendIJS5_EEEvDpOT_ \
+// RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE22__resize_and_overwriteIZNS_9to_stringEiEUlPcmE_EEvmT_ \
+// RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE22__resize_and_overwriteIZNS_9to_stringEjEUlPcmE_EEvmT_ \
+// RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE22__resize_and_overwriteIZNS_9to_stringEmEUlPcmE_EEvmT_ \
+// RUN:             -e _ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE17_M_realloc_appendIJRKS5_EEEvDpOT_ \
+// RUN:             -e _ZNSt6vectorISt10unique_ptrIKvSt8functionIFvPS1_EEESaIS6_EE17_M_realloc_appendIJS6_EEEvDpOT_ \
+// RUN:             -e _ZNSt6vectorISt8optionalISt4pairINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEbEESaIS9_EE17_M_realloc_appendIJRKS9_EEEvDpOT_ \
+// RUN:             -e _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE22__resize_and_overwriteIZNS_9to_stringElEUlPcmE_EEvmT_ \
 // RUN:   > %t/swiftRemoteMirror-all.txt
 // RUN: %llvm-nm --defined-only --extern-only --no-weak %platform-dylib-dir/%target-library-name(swiftRemoteMirror) > %t/swiftRemoteMirror-no-weak.txt
 // RUN: diff -u %t/swiftRemoteMirror-all.txt %t/swiftRemoteMirror-no-weak.txt
diff --git a/test/stmt/c_style_for.swift b/test/stmt/c_style_for.swift
index 7bd75d0e03147..4919681f20cb6 100644
--- a/test/stmt/c_style_for.swift
+++ b/test/stmt/c_style_for.swift
@@ -32,9 +32,9 @@ for ; other<count; other+=1 { // expected-error {{C-style for statement was remo
 }
 
 for (var number : Int8 = start; number < count; number+=1) { // expected-error {{C-style for statement was removed in Swift 3}} {{none}}
-  print(number)
+  print(number) // expected-error {{cannot find 'number' in scope}}
 }
 
 for (var m : Int8 = start; m < count; m+=1) { // expected-error {{C-style for statement was removed in Swift 3}} {{none}}
-  m += 3
+  m += 3 // expected-error {{cannot find 'm' in scope}}
 }
diff --git a/test/stmt/errors.swift b/test/stmt/errors.swift
index cf17c0700c6f7..964ce3b30d82a 100644
--- a/test/stmt/errors.swift
+++ b/test/stmt/errors.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 enum MSV : Error {
   case Foo, Bar, Baz
 
@@ -256,3 +256,17 @@ func takesClosure(_: (() -> ())) throws -> Int {}
 func passesClosure() {
     _ = try takesClosure { } // expected-error {{errors thrown from here are not handled}}
 }
+
+// Parameter packs checking
+struct S {
+  static func packTest<each T>(_ values: repeat (each T).Type, shouldThrow: Bool) throws -> Bool {
+    if (shouldThrow) {
+      throw MSV.Foo
+    }
+    return true
+  }
+
+  static func test() -> Bool {
+    return try packTest(String.self, String.self, shouldThrow: true) // expected-error{{errors thrown from here are not handled}}
+  }
+}
diff --git a/test/stmt/for-expr.swift b/test/stmt/for-expr.swift
new file mode 100644
index 0000000000000..dd9b9ea515fae
--- /dev/null
+++ b/test/stmt/for-expr.swift
@@ -0,0 +1,16 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature ForExpressions) | %FileCheck %s
+
+// REQUIRES: swift_feature_ForExpressions
+// REQUIRES: executable_test
+
+func f() -> String {
+  for (i, x) in "hello".enumerated() {
+    if i % 2 == 0 {
+      x.uppercased()
+    } else  {
+      "*skip*"
+
+    }
+  }
+}
+print(f()) // CHECK: H*skip*L*skip*O
diff --git a/test/stmt/foreach.swift b/test/stmt/foreach.swift
index 060b8decce95a..caea79b6cfa2a 100644
--- a/test/stmt/foreach.swift
+++ b/test/stmt/foreach.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 // Bad containers and ranges
 struct BadContainer1 {
@@ -351,3 +351,16 @@ do {
     }
   }
 }
+
+// Make sure the bodies still type-check okay if the preamble is invalid.
+func testInvalidPreamble() {
+  func takesAutoclosure(_ x: @autoclosure () -> Int) -> Int { 0 }
+
+  for _ in undefined { // expected-error {{cannot find 'undefined' in scope}}
+    let a = takesAutoclosure(0) // Fine
+  }
+  for x in undefined { // expected-error {{cannot find 'undefined' in scope}}
+    let b: Int = x  // No type error, `x` is invalid.
+    _ = "" as Int // expected-error {{cannot convert value of type 'String' to type 'Int' in coercion}}
+  }
+}
diff --git a/test/stmt/if_while_var.swift b/test/stmt/if_while_var.swift
index ea5a9e347231e..3b620819ca44d 100644
--- a/test/stmt/if_while_var.swift
+++ b/test/stmt/if_while_var.swift
@@ -64,7 +64,8 @@ if case let x? = nonOptionalEnum() { _ = x } // expected-error{{'?' pattern cann
 if let x { _ = x } // expected-error{{cannot find 'x' in scope}}
 
 if let optional: String { _ = optional }
-if let optional: Int { _ = optional } // expected-error{{cannot convert value of type 'String?' to specified type 'Int?'}}
+if let optional: Int { _ = optional } // expected-error{{cannot assign value of type 'String?' to type 'Int?'}}
+// expected-note@-1 {{arguments to generic parameter 'Wrapped' ('String' and 'Int') are expected to be equal}}
 
 class B {} // expected-note * {{did you mean 'B'?}}
 class D : B {}// expected-note * {{did you mean 'D'?}}
diff --git a/test/stmt/typed_throws.swift b/test/stmt/typed_throws.swift
index 46da4c294a1dc..be7eeb39d502d 100644
--- a/test/stmt/typed_throws.swift
+++ b/test/stmt/typed_throws.swift
@@ -12,6 +12,8 @@ case dogAteIt
 case forgot
 }
 
+struct GenericError<T>: Error {}
+
 func processMyError(_: MyError) { }
 
 func doSomething() throws(MyError) { }
@@ -361,11 +363,11 @@ func testSequenceExpr() async throws(Never) {
 
   _ = unsafe await try! getIntAsync() + getIntAsync()
   // expected-warning@-1 {{'try' must precede 'await'}}
-
+  // expected-warning@-2{{no unsafe operations occur within 'unsafe' expression}}
   _ = try unsafe await try! getIntAsync() + getIntAsync()
   // expected-warning@-1 {{'try' must precede 'await'}}
   // expected-warning@-2 {{no calls to throwing functions occur within 'try' expression}}
-
+  // expected-warning@-3{{no unsafe operations occur within 'unsafe' expression}}
   try _ = (try! getInt()) + getInt()
   // expected-error@-1:29 {{thrown expression type 'any Error' cannot be converted to error type 'Never'}}
 
@@ -418,3 +420,12 @@ func testSequenceExpr() async throws(Never) {
   try true ? 0 : try! getInt() ~~~ getInt()
   // expected-error@-1 {{'try!' following conditional operator does not cover everything to its right}}
 }
+
+func testPlaceholder() {
+  do throws(_) {} catch {}
+  // expected-error@-1 {{type placeholder not allowed here}}
+  // expected-warning@-2 {{'catch' block is unreachable because no errors are thrown in 'do' block}}
+  do throws(GenericError<_>) {} catch {}
+  // expected-error@-1 {{type placeholder not allowed here}}
+  // expected-warning@-2 {{'catch' block is unreachable because no errors are thrown in 'do' block}}
+}
diff --git a/test/type/builtin_types.swift b/test/type/builtin_types.swift
index 2d54a255a1701..5ca582129601e 100644
--- a/test/type/builtin_types.swift
+++ b/test/type/builtin_types.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -parse-stdlib
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -parse-stdlib
 
 import Swift
 
diff --git a/test/type/explicit_existential.swift b/test/type/explicit_existential.swift
index 1e7deb76c9296..8127e162eac30 100644
--- a/test/type/explicit_existential.swift
+++ b/test/type/explicit_existential.swift
@@ -1,14 +1,14 @@
-// RUN: %target-typecheck-verify-swift \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated \
 // RUN:   -verify-additional-prefix default-swift-mode-
 
-// RUN: %target-typecheck-verify-swift -swift-version 6 \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -swift-version 6 \
 // RUN:   -verify-additional-prefix swift-6-
 
-// RUN: %target-typecheck-verify-swift -enable-upcoming-feature ExistentialAny \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-upcoming-feature ExistentialAny \
 // RUN:   -verify-additional-prefix default-swift-mode- \
 // RUN:   -verify-additional-prefix explicit-any-
 
-// RUN: %target-typecheck-verify-swift -enable-upcoming-feature ExistentialAny:adoption \
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-upcoming-feature ExistentialAny:migrate \
 //        To verify that the message is not followed by
 //        "; this will be an error ...".
 // RUN:   -verify-additional-prefix default-swift-mode- \
@@ -90,7 +90,7 @@ protocol HasAssoc {
 
 do {
   enum MyError: Error {
-    case bad(Any) // expected-swift-6-error {{associated value 'bad' of 'Sendable'-conforming enum 'MyError' has non-sendable type 'Any'}}
+    case bad(Any) // expected-swift-6-warning {{associated value 'bad' of 'Sendable'-conforming enum 'MyError' has non-Sendable type 'Any'}}
   }
 
   func checkIt(_ js: Any) throws {
diff --git a/test/type/explicit_existential_cyclic_protocol.swift b/test/type/explicit_existential_cyclic_protocol.swift
index 53ac25f68efe9..399ff54f26148 100644
--- a/test/type/explicit_existential_cyclic_protocol.swift
+++ b/test/type/explicit_existential_cyclic_protocol.swift
@@ -3,14 +3,13 @@
 
 // REQUIRES: swift_feature_ExistentialAny
 
-// 'HasSelfOrAssociatedTypeRequirementsRequest' should evaluate to false in
-// the event of a cycle because we will have considered all the protocols in a
-// cyclic hierarchy by the time the cycle is hit.
+// 'HasSelfOrAssociatedTypeRequirementsRequest' evaluates to false in the event
+// of a cycle.
 do {
   do {
     protocol P1 : P2 {}
-    // expected-no-explicit-any-note@-1 2 {{protocol 'P1' declared here}}
-    // expected-explicit-any-note@-2 1 {{protocol 'P1' declared here}}
+    // expected-no-explicit-any-note@-1 2 {{through protocol 'P1' declared here}}
+    // expected-explicit-any-note@-2 1 {{through protocol 'P1' declared here}}
     protocol P2 : P1 {}
     // expected-no-explicit-any-error@-1 2 {{protocol 'P2' refines itself}}
     // expected-explicit-any-error@-2 1 {{protocol 'P2' refines itself}}
@@ -23,13 +22,13 @@ do {
   do {
     protocol P0 { associatedtype A }
     protocol P1 : P2, P0 {}
-    // expected-no-explicit-any-note@-1 2 {{protocol 'P1' declared here}}
-    // expected-explicit-any-note@-2 1 {{protocol 'P1' declared here}}
+    // expected-no-explicit-any-note@-1 2 {{through protocol 'P1' declared here}}
+    // expected-explicit-any-note@-2 1 {{through protocol 'P1' declared here}}
     protocol P2 : P1 {}
     // expected-no-explicit-any-error@-1 2 {{protocol 'P2' refines itself}}
     // expected-explicit-any-error@-2 1 {{protocol 'P2' refines itself}}
 
     let _: P2
-    // expected-warning@-1 {{use of protocol 'P2' as a type must be written 'any P2'}}
+    // expected-explicit-any-warning@-1 {{use of protocol 'P2' as a type must be written 'any P2'}}
   }
 }
diff --git a/test/type/implicit_some/explicit_existential.swift b/test/type/implicit_some/explicit_existential.swift
index f830cfa0699b6..0d33cc42ff893 100644
--- a/test/type/implicit_some/explicit_existential.swift
+++ b/test/type/implicit_some/explicit_existential.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -disable-availability-checking -enable-experimental-feature ImplicitSome
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -disable-availability-checking -enable-experimental-feature ImplicitSome
 
 // REQUIRES: swift_feature_ImplicitSome
 
diff --git a/test/type/implicit_some/opaque_parameters.swift b/test/type/implicit_some/opaque_parameters.swift
index 999352133fa70..15514343c41d1 100644
--- a/test/type/implicit_some/opaque_parameters.swift
+++ b/test/type/implicit_some/opaque_parameters.swift
@@ -86,5 +86,5 @@ func testPrimaries(
   takePrimaryCollections(setOfStrings, setOfInts)
   takePrimaryCollections(setOfStrings, arrayOfInts)
   _ = takeMatchedPrimaryCollections(arrayOfInts, setOfInts)
-  _ = takeMatchedPrimaryCollections(arrayOfInts, setOfStrings) // expected-error{{type of expression is ambiguous without a type annotation}}
+  _ = takeMatchedPrimaryCollections(arrayOfInts, setOfStrings) // expected-error{{failed to produce diagnostic for expression}}
 }
diff --git a/test/type/inline_array.swift b/test/type/inline_array.swift
index 1e31a217c1c9d..63b39e156b6f2 100644
--- a/test/type/inline_array.swift
+++ b/test/type/inline_array.swift
@@ -1,49 +1,47 @@
-// RUN: %target-typecheck-verify-swift -enable-experimental-feature InlineArrayTypeSugar -disable-availability-checking
+// RUN: %target-typecheck-verify-swift -disable-availability-checking
 
-// REQUIRES: swift_feature_InlineArrayTypeSugar
+let _: [3 of Int]
+let _ = [3 of Int](repeating: 0)
+let _ = [3 of [3 of Int]](repeating: [1, 2, 3])
 
-let _: [3 x Int]
-let _ = [3 x Int](repeating: 0)
-let _ = [3 x [3 x Int]](repeating: [1, 2, 3])
-
-let _ = [[3 x Int] x Int]() // expected-error {{cannot pass type '[3 x Int]' as a value for generic value 'count'}}
+let _ = [[3 of Int] of Int]() // expected-error {{cannot pass type '[3 of Int]' as a value for generic value 'count'}}
 
 do {
-  let _: [3 x
+  let _: [3 of
   // expected-error@-1 {{expected type}}
 }
 
 do {
-  let _: [3 x Int // expected-note {{to match this opening '['}}
+  let _: [3 of Int // expected-note {{to match this opening '['}}
 } // expected-error {{expected ']' in inline array type}}
 
 // We don't currently allow multi-line.
-func testMultiline(_ x: Int) {
+func testMultiline(_ of: Int) {
   let _ = [ // expected-error {{cannot call value of non-function type '[Int]'}}
     3 // expected-error {{expected ',' separator}}
-    x
+    of
     Int
   ](repeating: 0)
 
   let _ = [3
-    x
+    of
     Int
   ](repeating: 0)
   // expected-error@-4 {{expected ',' separator}}
   // expected-error@-5 {{cannot call value of non-function type '[Int]'}}
 
   let _ = [3
-           x Int](repeating: 0)
+           of Int](repeating: 0)
   // expected-error@-2 {{cannot call value of non-function type '[Int]'}}
   // expected-error@-3 {{expected ',' separator}}
 
   // This is okay.
-  let _ = [3 x
+  let _ = [3 of
              Int](repeating: 0)
 
   // So's this
   let _ = [
-    3 x Int
+    3 of Int
   ](repeating: 0)
 }
 
@@ -52,58 +50,58 @@ protocol Q {}
 
 struct S<T> {}
 
-let _ = S<[3 x Int]>()
-let _ = S<[[3 x Int]]>()
+let _ = S<[3 of Int]>()
+let _ = S<[[3 of Int]]>()
 
 // Make sure we can recover for different type productions as the LHS.
-let _ = S<[[Int x 3]]>()
+let _ = S<[[Int of 3]]>()
 // expected-error@-1 {{element count must precede inline array element type}}
-let _ = S<[@escaping () -> Int x 3]>()
+let _ = S<[@escaping () -> Int of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
-// expected-error@-2 {{@escaping attribute may only be used in function parameter position}}
-let _ = S<[Int.Type x 3]>()
+// expected-error@-2 {{'@escaping' may only be used in function parameter position}}
+let _ = S<[Int.Type of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
-let _ = S<[sending P & Q x 3]>()
+let _ = S<[sending P & Q of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
 // expected-error@-2 {{'sending' may only be used on parameters and results}}
-let _ = S<[some P & Q -> Int x 3]>()
+let _ = S<[some P & Q -> Int of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
 // expected-error@-2 {{single argument function types require parentheses}}
 // expected-error@-3 {{'some' types are only permitted in properties, subscripts, and functions}}
-let _ = S<[~P x 3]>()
+let _ = S<[~P of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
 // expected-error@-2 {{type 'P' cannot be suppressed}}
-let _ = S<[(Int, String) x 3]>()
+let _ = S<[(Int, String) of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
-let _ = S<[[3 x Int] x 3]>()
+let _ = S<[[3 of Int] of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
-let _ = S<[[Int] x 3]>()
+let _ = S<[[Int] of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
-let _ = S<[Array<Int> x 3]>()
+let _ = S<[Array<Int> of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
-let _ = S<[_ x 3]>()
+let _ = S<[_ of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
 // expected-error@-2 {{could not infer type for placeholder}}
-let _ = S<[_? x 3]>()
+let _ = S<[_? of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
 // expected-error@-2 {{could not infer type for placeholder}}
-let _ = S<[_?x 3]>()
+let _ = S<[_?of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
 // expected-error@-2 {{could not infer type for placeholder}}
-let _ = S<[_! x 3]>()
+let _ = S<[_! of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
 // expected-warning@-2 {{using '!' here is deprecated; this is an error in the Swift 5 language mode}}
 // expected-note@-3 {{use '?' instead}}
 // expected-error@-4 {{could not infer type for placeholder}}
-let _ = S<[_!x 3]>()
+let _ = S<[_!of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
 // expected-warning@-2 {{using '!' here is deprecated; this is an error in the Swift 5 language mode}}
 // expected-note@-3 {{use '?' instead}}
 // expected-error@-4 {{could not infer type for placeholder}}
-let _ = S<[Int?x 3]>()
+let _ = S<[Int?of 3]>()
 // expected-error@-1 {{element count must precede inline array element type}}
 
-func testEllipsis(_ x: Int) {
-  // Make sure this isn't parsed as '<variadic-type> x <missing type>'
-  let _ = [x...x]
+func testEllipsis(_ of: Int) {
+  // Make sure this isn't parsed as '<variadic-type> of <missing type>'
+  let _ = [of...of]
 }
diff --git a/test/type/inline_array_disabled.swift b/test/type/inline_array_disabled.swift
deleted file mode 100644
index 4f4a790b4c4f7..0000000000000
--- a/test/type/inline_array_disabled.swift
+++ /dev/null
@@ -1,19 +0,0 @@
-// RUN: %target-typecheck-verify-swift
-
-// Make sure InlineArray type sugar is disabled by default.
-// FIXME: The recovery here really isn't great.
-do {
-  let _: [3 x Int] // expected-note {{to match this opening '['}}
-  // expected-error@-1 4{{expected}}
-  // expected-error@-2 4{{consecutive statements on a line must be separated by ';'}}
-  // expected-warning@-3 2{{is unused}}
-  // expected-error@-4 {{cannot find 'x' in scope}}
-  // expected-note@-5 {{add arguments after the type to construct a value of the type}}
-  // expected-note@-6 {{use '.self' to reference the type object}}
-}
-do {
-  let _ = [3 x Int]()
-  // expected-error@-1 {{cannot call value of non-function type '[Int]'}}
-  // expected-error@-2 {{expected ',' separator}}
-  // expected-error@-3 {{cannot find 'x' in scope}}
-}
diff --git a/test/type/nested_types.swift b/test/type/nested_types.swift
index c86370af598dc..acd2ae16a87a4 100644
--- a/test/type/nested_types.swift
+++ b/test/type/nested_types.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -module-name test
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -module-name test
 
 struct X {
   typealias MyInt = Int
diff --git a/test/type/objc_direct.swift b/test/type/objc_direct.swift
index e0ef19e47ffc4..2b2682e262f41 100644
--- a/test/type/objc_direct.swift
+++ b/test/type/objc_direct.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-objc-interop -import-objc-header %S/../Inputs/objc_direct.h
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-objc-interop -import-objc-header %S/../Inputs/objc_direct.h
 
 // REQUIRES: objc_interop
 
diff --git a/test/type/opaque.swift b/test/type/opaque.swift
index 87dbd5bcb08c9..66d5603a0eced 100644
--- a/test/type/opaque.swift
+++ b/test/type/opaque.swift
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -disable-availability-checking -typecheck -verify %s
+// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -typecheck -verify %s
 
 protocol P {
   func paul()
@@ -205,13 +205,6 @@ struct MismatchedReturnTypesSubscript {
   }
 }
 
-func jan() -> some P {
-  return [marcia(), marcia(), marcia()]
-}
-func marcia() -> some P {
-  return [marcia(), marcia(), marcia()] // expected-error{{defines the opaque type in terms of itself}} {{documentation-file=opaque-type-inference}}
-}
-
 protocol R {
   associatedtype S: P, Q // expected-note*{{}}
 
diff --git a/test/type/opaque_availability.swift b/test/type/opaque_availability.swift
index eb7348acf875a..2514d0bb86668 100644
--- a/test/type/opaque_availability.swift
+++ b/test/type/opaque_availability.swift
@@ -5,7 +5,7 @@
 protocol P {}
 struct X: P {}
 
-func alwaysOpaque() -> some P { return X() } // expected-only-available-error{{'some' return types are only available}} expected-only-available-note{{add @available}}
+func alwaysOpaque() -> some P { return X() } // expected-only-available-error{{'some' return types are only available}} expected-only-available-note{{add '@available'}}
 
 @available(SwiftStdlib 5.1, *)
 func sometimesOpaque() -> some P { return X() }
diff --git a/test/type/opaque_parameters.swift b/test/type/opaque_parameters.swift
index a848269a7c4ad..99beb29d3c615 100644
--- a/test/type/opaque_parameters.swift
+++ b/test/type/opaque_parameters.swift
@@ -106,7 +106,7 @@ func testPrimaries(
   takePrimaryCollections(setOfStrings, setOfInts)
   takePrimaryCollections(setOfStrings, arrayOfInts)
   _ = takeMatchedPrimaryCollections(arrayOfInts, setOfInts)
-  _ = takeMatchedPrimaryCollections(arrayOfInts, setOfStrings) // expected-error{{type of expression is ambiguous without a type annotation}}
+  _ = takeMatchedPrimaryCollections(arrayOfInts, setOfStrings) // expected-error{{failed to produce diagnostic for expression}}
 }
 
 
diff --git a/test/type/parameterized_existential.swift b/test/type/parameterized_existential.swift
index 55032bcf3c60e..0d9acb20d1f89 100644
--- a/test/type/parameterized_existential.swift
+++ b/test/type/parameterized_existential.swift
@@ -82,16 +82,6 @@ func typeExpr() {
   _ = (any Sequence<Int>).self
 }
 
-/// Not supported as a protocol composition term for now
-
-protocol SomeProto {}
-
-func protocolCompositionNotSupported1(_: SomeProto & Sequence<Int>) {}
-// expected-error@-1 {{non-protocol, non-class type 'Sequence<Int>' cannot be used within a protocol-constrained type}}
-
-func protocolCompositionNotSupported2(_: any SomeProto & Sequence<Int>) {}
-// expected-error@-1 {{non-protocol, non-class type 'Sequence<Int>' cannot be used within a protocol-constrained type}}
-
 func increment(_ n : any Collection<Float>) {
   for value in n {
       _ = value + 1
diff --git a/test/type/parameterized_protocol.swift b/test/type/parameterized_protocol.swift
index 83f7a74ca4d9c..39645c256797a 100644
--- a/test/type/parameterized_protocol.swift
+++ b/test/type/parameterized_protocol.swift
@@ -31,7 +31,6 @@ protocol Invalid5<Element, Element> {
 
 protocol Sequence<Element> {
   associatedtype Element
-  // expected-note@-1 2{{protocol requires nested type 'Element'}}
 }
 
 extension Sequence {
@@ -56,14 +55,6 @@ struct ConcreteEquatableSequence<Element : Equatable> : EquatableSequence {}
 protocol IntSequence : Sequence<Int> {}
 
 
-/// Concrete types cannot inherit from a parameterized protocol
-
-struct SillyStruct : Sequence<Int> {}
-// expected-error@-1 {{cannot inherit from protocol type with generic argument 'Sequence<Int>'}}
-// expected-error@-2 {{type 'SillyStruct' does not conform to protocol 'Sequence'}}
-// expected-note@-3 {{add stubs for conformance}}
-
-
 /// Parameterized protocol in generic parameter inheritance clause
 
 // CHECK-LABEL: parameterized_protocol.(file).IntSequenceWrapper@
@@ -213,12 +204,6 @@ protocol TestCompositionProtocol1 {
   associatedtype S : Sequence<Int> & Sendable
 }
 
-struct TestStructComposition : Sequence<Int> & Sendable {}
-// expected-error@-1 {{cannot inherit from protocol type with generic argument 'Sequence<Int>'}}
-// expected-error@-2 {{type 'TestStructComposition' does not conform to protocol 'Sequence'}}
-// expected-note@-3 {{add stubs for conformance}}
-
-
 /// Conflicts
 
 protocol Pair<X, Y> where Self.X == Self.Y {
diff --git a/test/type/subclass_composition_objc.swift b/test/type/subclass_composition_objc.swift
index e3e7c2088ac3d..87bad453993b6 100644
--- a/test/type/subclass_composition_objc.swift
+++ b/test/type/subclass_composition_objc.swift
@@ -13,12 +13,12 @@ class SomeMethods {
 
   @objc
   func cannotRepresentInObjC(x: SwiftClass & ObjCProtocol) {}
-  // expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // expected-error@-1 {{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing class 'SwiftClass' cannot be represented in Objective-C}}
 
   @objc
   func alsoCannotRepresentInObjC(x: ObjCClass & SwiftProtocol) {}
-  // expected-error@-1 {{method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C}}
+  // expected-error@-1 {{method cannot be marked '@objc' because the type of the parameter cannot be represented in Objective-C}}
   // expected-note@-2 {{protocol-constrained type containing protocol 'SwiftProtocol' cannot be represented in Objective-C}}
 }
 
diff --git a/test/type/types.swift b/test/type/types.swift
index 09b217c147875..ba577308b748f 100644
--- a/test/type/types.swift
+++ b/test/type/types.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 var a : Int
 
@@ -196,7 +196,7 @@ typealias A = (inout Int ..., Int ... = [42, 12]) -> Void // expected-error {{'i
 
 // rdar://94888357 - failed to produce a diagnostic when type is used incorrectly
 func rdar94888357() {
-  struct S<T> { // expected-note {{generic type 'S' declared here}}
+  struct S<T> { // expected-note {{generic struct 'S' declared here}}
     init(_ str: String) {}
   }
 
@@ -219,3 +219,34 @@ do {
     subscript(_: inout Double...) -> Bool { true } // expected-error {{'inout' may only be used on function or initializer parameters}}
   }
 }
+
+let tupleTypeWithTrailingComma: (
+  bar: String,
+  quux: String,
+)
+
+let _ = (bar: String, quux: String,).self
+
+let closureTypeWithTrailingCommas: (
+  String,
+  String,
+) -> (
+  bar: String,
+  quux: String,
+)
+
+let _ = Array<(
+  foo: Int,
+  bar: String,
+)>()
+
+let _ = Dictionary<
+  String,
+  Dictionary<
+    String,
+    Array<(
+      foo: Int,
+      bar: String,
+    )>,
+  >,
+>()
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 3f8fee3e1314e..902697efea232 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -22,7 +22,6 @@ add_swift_tool_subdirectory(swift-demangle)
 add_swift_tool_subdirectory(swift-demangle-yamldump)
 add_swift_tool_subdirectory(swift-def-to-strings-converter)
 add_swift_tool_subdirectory(swift-serialize-diagnostics)
-add_swift_tool_subdirectory(swift-ast-script)
 add_swift_tool_subdirectory(swift-refactor)
 add_swift_tool_subdirectory(libStaticMirror)
 add_swift_tool_subdirectory(libMockPlugin)
diff --git a/tools/SourceKit/CMakeLists.txt b/tools/SourceKit/CMakeLists.txt
index 1e00633ca033d..73b79d13c8c42 100644
--- a/tools/SourceKit/CMakeLists.txt
+++ b/tools/SourceKit/CMakeLists.txt
@@ -79,16 +79,6 @@ if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
   else()
     message(FATAL_ERROR "Can't understand SOURCEKIT_DEPLOYMENT_OS '${SOURCEKIT_DEPLOYMENT_OS}';")
   endif()
-
-  # Add deployment target to C/C++ compiler and linker flags.
-  # FIXME: CMAKE_OSX_DEPLOYMENT_TARGET falls over when used for iOS versions.
-  if (XCODE)
-    if (SOURCEKIT_DEPLOYMENT_OS MATCHES "^macosx")
-      set(CMAKE_XCODE_ATTRIBUTE_MACOSX_DEPLOYMENT_TARGET ${SOURCEKIT_DEPLOYMENT_TARGET})
-    else()
-      set(CMAKE_XCODE_ATTRIBUTE_IPHONEOS_DEPLOYMENT_TARGET ${SOURCEKIT_DEPLOYMENT_TARGET})
-    endif()
-  endif()
 endif()
 
 include_directories(BEFORE
diff --git a/tools/SourceKit/cmake/modules/AddSwiftSourceKit.cmake b/tools/SourceKit/cmake/modules/AddSwiftSourceKit.cmake
index c03e4ea508e9a..289b86b4ed422 100644
--- a/tools/SourceKit/cmake/modules/AddSwiftSourceKit.cmake
+++ b/tools/SourceKit/cmake/modules/AddSwiftSourceKit.cmake
@@ -103,7 +103,7 @@ function(add_sourcekit_swift_runtime_link_flags target path HAS_SWIFT_MODULES)
                    LINK_FLAGS " -lobjc ")
 
     endif() # HAS_SWIFT_MODULES AND ASKD_BOOTSTRAPPING_MODE
-  elseif(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD" AND HAS_SWIFT_MODULES AND ASKD_BOOTSTRAPPING_MODE)
+  elseif(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|FREEBSD|OPENBSD" AND HAS_SWIFT_MODULES AND ASKD_BOOTSTRAPPING_MODE)
     set(swiftrt "swiftImageRegistrationObject${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_OBJECT_FORMAT}-${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}-${SWIFT_HOST_VARIANT_ARCH}")
     if(ASKD_BOOTSTRAPPING_MODE MATCHES "HOSTTOOLS|CROSSCOMPILE")
       if(ASKD_BOOTSTRAPPING_MODE MATCHES "HOSTTOOLS")
@@ -111,6 +111,19 @@ function(add_sourcekit_swift_runtime_link_flags target path HAS_SWIFT_MODULES)
         # installed host toolchain.
         get_filename_component(swift_bin_dir ${SWIFT_EXEC_FOR_SWIFT_MODULES} DIRECTORY)
         get_filename_component(swift_dir ${swift_bin_dir} DIRECTORY)
+
+        # Detect and handle swiftly-managed hosts.
+        if(swift_bin_dir MATCHES ".*/swiftly/bin")
+          execute_process(COMMAND swiftly use --print-location
+            OUTPUT_VARIABLE swiftly_dir
+            ERROR_VARIABLE err)
+          if(err)
+            message(SEND_ERROR "Failed to find swiftly Swift compiler")
+          endif()
+          string(STRIP "${swiftly_dir}" swiftly_dir)
+          set(swift_dir "${swiftly_dir}/usr")
+        endif()
+
         set(host_lib_dir "${swift_dir}/lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
       else()
         set(host_lib_dir "${SWIFTLIB_DIR}/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
@@ -158,7 +171,7 @@ function(add_sourcekit_swift_runtime_link_flags target path HAS_SWIFT_MODULES)
       # Add rpath to the host Swift libraries.
       file(RELATIVE_PATH relative_hostlib_path "${path}" "${SWIFTLIB_DIR}/host/compiler")
       list(APPEND RPATH_LIST "@loader_path/${relative_hostlib_path}")
-    elseif(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD")
+    elseif(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|FREEBSD|OPENBSD")
       # Add rpath to the host Swift libraries.
       file(RELATIVE_PATH relative_hostlib_path "${path}" "${SWIFTLIB_DIR}/host/compiler")
       list(APPEND RPATH_LIST "$ORIGIN/${relative_hostlib_path}")
diff --git a/tools/SourceKit/include/SourceKit/Core/Context.h b/tools/SourceKit/include/SourceKit/Core/Context.h
index 5e7118a47025f..4b4b91f3004a5 100644
--- a/tools/SourceKit/include/SourceKit/Core/Context.h
+++ b/tools/SourceKit/include/SourceKit/Core/Context.h
@@ -166,7 +166,6 @@ class Context {
   /// Used to find clang relative to it.
   std::string SwiftExecutablePath;
   std::string RuntimeLibPath;
-  std::string DiagnosticDocumentationPath;
   std::unique_ptr<LangSupport> SwiftLang;
   std::shared_ptr<NotificationCenter> NotificationCtr;
   std::shared_ptr<GlobalConfig> Config;
@@ -176,7 +175,6 @@ class Context {
 
 public:
   Context(StringRef SwiftExecutablePath, StringRef RuntimeLibPath,
-          StringRef DiagnosticDocumentationPath,
           llvm::function_ref<std::unique_ptr<LangSupport>(Context &)>
               LangSupportFactoryFn,
           llvm::function_ref<std::shared_ptr<PluginSupport>(Context &)>
@@ -187,9 +185,6 @@ class Context {
   StringRef getSwiftExecutablePath() const { return SwiftExecutablePath; }
 
   StringRef getRuntimeLibPath() const { return RuntimeLibPath; }
-  StringRef getDiagnosticDocumentationPath() const {
-    return DiagnosticDocumentationPath;
-  }
 
   LangSupport &getSwiftLangSupport() { return *SwiftLang; }
 
diff --git a/tools/SourceKit/include/SourceKit/Core/LangSupport.h b/tools/SourceKit/include/SourceKit/Core/LangSupport.h
index 4b143b0f8ea8c..d60a7f6cd979d 100644
--- a/tools/SourceKit/include/SourceKit/Core/LangSupport.h
+++ b/tools/SourceKit/include/SourceKit/Core/LangSupport.h
@@ -35,6 +35,12 @@ namespace llvm {
   class MemoryBuffer;
 }
 
+namespace swift {
+namespace ide {
+struct FormattedSignatureHelp;
+} // namespace ide
+} // namespace swift
+
 namespace SourceKit {
 class GlobalConfig;
 using swift::ide::CancellableResult;
@@ -213,7 +219,8 @@ struct FilterRule {
 
 enum class DiagnosticSeverityKind {
   Warning,
-  Error
+  Error,
+  Remark
 };
 
 enum class DiagnosticCategory {
@@ -922,6 +929,7 @@ struct IndexStoreOptions {
   bool IgnoreStdlib = false;
   bool DisableImplicitModules = false;
   bool IncludeLocals = false;
+  bool Compress = false;
 };
 
 struct IndexStoreInfo{};
@@ -1010,6 +1018,19 @@ class ConformingMethodListConsumer {
   virtual void cancelled() = 0;
 };
 
+class SignatureHelpConsumer {
+  virtual void anchor();
+
+public:
+  virtual ~SignatureHelpConsumer() {}
+
+  virtual void
+  handleResult(const swift::ide::FormattedSignatureHelp &Result) = 0;
+  virtual void setReusingASTContext(bool flag) = 0;
+  virtual void failed(StringRef ErrDescription) = 0;
+  virtual void cancelled() = 0;
+};
+
 struct CompilationResult {
   unsigned int ResultStatus;
   llvm::ArrayRef<DiagnosticEntryInfo> Diagnostics;
@@ -1107,6 +1128,7 @@ class LangSupport {
   virtual void
   editorOpenSwiftSourceInterface(StringRef Name, StringRef SourceName,
                                  ArrayRef<const char *> Args,
+                                 bool CancelOnSubsequentRequest,
                                  SourceKitCancellationToken CancellationToken,
                                  std::shared_ptr<EditorConsumer> Consumer) = 0;
 
@@ -1216,12 +1238,14 @@ class LangSupport {
   virtual void
   findLocalRenameRanges(StringRef Filename, unsigned Line, unsigned Column,
                         unsigned Length, ArrayRef<const char *> Args,
+                        bool CancelOnSubsequentRequest,
                         SourceKitCancellationToken CancellationToken,
                         CategorizedRenameRangesReceiver Receiver) = 0;
 
   virtual void semanticRefactoring(StringRef PrimaryFilePath,
                                    SemanticRefactoringInfo Info,
                                    ArrayRef<const char *> Args,
+                                   bool CancelOnSubsequentRequest,
                                    SourceKitCancellationToken CancellationToken,
                                    CategorizedEditsReceiver Receiver) = 0;
 
@@ -1240,6 +1264,7 @@ class LangSupport {
       StringRef PrimaryFilePath, StringRef InputBufferName,
       ArrayRef<const char *> Args, std::optional<unsigned> Offset,
       std::optional<unsigned> Length, bool FullyQualified,
+      bool CancelOnSubsequentRequest,
       SourceKitCancellationToken CancellationToken,
       std::function<void(const RequestResult<VariableTypesInFile> &)>
           Receiver) = 0;
@@ -1262,6 +1287,12 @@ class LangSupport {
       ConformingMethodListConsumer &Consumer,
       std::optional<VFSOptions> vfsOptions) = 0;
 
+  virtual void getSignatureHelp(StringRef PrimaryFilePath, unsigned Offset,
+                                ArrayRef<const char *> Args,
+                                SourceKitCancellationToken CancellationToken,
+                                SignatureHelpConsumer &Consumer,
+                                std::optional<VFSOptions> vfsOptions) = 0;
+
   virtual void expandMacroSyntactically(llvm::MemoryBuffer *inputBuf,
                                         ArrayRef<const char *> args,
                                         ArrayRef<MacroExpansionInfo> expansions,
diff --git a/tools/SourceKit/lib/Core/Context.cpp b/tools/SourceKit/lib/Core/Context.cpp
index 6f8bba5667289..13d3ec6822d1e 100644
--- a/tools/SourceKit/lib/Core/Context.cpp
+++ b/tools/SourceKit/lib/Core/Context.cpp
@@ -37,14 +37,12 @@ GlobalConfig::getIDEInspectionOpts() const {
 
 SourceKit::Context::Context(
     StringRef SwiftExecutablePath, StringRef RuntimeLibPath,
-    StringRef DiagnosticDocumentationPath,
     llvm::function_ref<std::unique_ptr<LangSupport>(Context &)>
         LangSupportFactoryFn,
     llvm::function_ref<std::shared_ptr<PluginSupport>(Context &)>
         PluginSupportFactoryFn,
     bool shouldDispatchNotificationsOnMain)
     : SwiftExecutablePath(SwiftExecutablePath), RuntimeLibPath(RuntimeLibPath),
-      DiagnosticDocumentationPath(DiagnosticDocumentationPath),
       NotificationCtr(
           new NotificationCenter(shouldDispatchNotificationsOnMain)),
       Config(new GlobalConfig()), ReqTracker(new RequestTracker()),
diff --git a/tools/SourceKit/lib/Core/LangSupport.cpp b/tools/SourceKit/lib/Core/LangSupport.cpp
index 1d3a0df0e74c5..26cafa8143a27 100644
--- a/tools/SourceKit/lib/Core/LangSupport.cpp
+++ b/tools/SourceKit/lib/Core/LangSupport.cpp
@@ -21,4 +21,5 @@ void OptionsDictionary::anchor() {}
 void DocInfoConsumer::anchor() { }
 void TypeContextInfoConsumer::anchor() { }
 void ConformingMethodListConsumer::anchor() { }
+void SignatureHelpConsumer::anchor() {}
 void LangSupport::anchor() { }
diff --git a/tools/SourceKit/lib/Support/ImmutableTextBuffer.cpp b/tools/SourceKit/lib/Support/ImmutableTextBuffer.cpp
index 81a4623b1a93b..0ebf2619ba200 100644
--- a/tools/SourceKit/lib/Support/ImmutableTextBuffer.cpp
+++ b/tools/SourceKit/lib/Support/ImmutableTextBuffer.cpp
@@ -11,13 +11,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "SourceKit/Support/ImmutableTextBuffer.h"
-#include "clang/Rewrite/Core/RewriteRope.h"
+#include "llvm/ADT/RewriteRope.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/SourceMgr.h"
 
 using namespace SourceKit;
 using namespace llvm;
-using clang::RewriteRope;
+using llvm::RewriteRope;
 
 void ImmutableTextUpdate::anchor() {}
 
diff --git a/tools/SourceKit/lib/SwiftLang/CMakeLists.txt b/tools/SourceKit/lib/SwiftLang/CMakeLists.txt
index 0037e5a040392..3cd81d50ec1a1 100644
--- a/tools/SourceKit/lib/SwiftLang/CMakeLists.txt
+++ b/tools/SourceKit/lib/SwiftLang/CMakeLists.txt
@@ -4,6 +4,7 @@ add_sourcekit_library(SourceKitSwiftLang
   SwiftCompile.cpp
   SwiftCompletion.cpp
   SwiftConformingMethodList.cpp
+  SwiftSignatureHelp.cpp
   SwiftDocSupport.cpp
   SwiftEditor.cpp
   SwiftEditorInterfaceGen.cpp
diff --git a/tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.cpp b/tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.cpp
index bbbabb2f6d499..95c344018b985 100644
--- a/tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.cpp
+++ b/tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.cpp
@@ -139,9 +139,9 @@ bool SourceKit::CodeCompletion::addCustomCompletions(
             ContextFreeNotRecommendedReason::None,
             CodeCompletionDiagnosticSeverity::None, /*DiagnosticMessage=*/"");
     auto *swiftResult = new (sink.allocator) CodeCompletion::SwiftResult(
-        *contextFreeResult, SemanticContextKind::Local,
-        CodeCompletionFlairBit::ExpressionSpecific,
-        /*NumBytesToErase=*/0, CodeCompletionResultTypeRelation::Unrelated,
+        *contextFreeResult, /*DeclOrCtx=*/nullptr, SemanticContextKind::Local,
+        CodeCompletionFlairBit::ExpressionSpecific, /*NumBytesToErase=*/0,
+        CodeCompletionResultTypeRelation::Unrelated,
         ContextualNotRecommendedReason::None);
 
     CompletionBuilder builder(sink, *swiftResult);
@@ -847,10 +847,7 @@ static void sortTopN(const Options &options, Group *group,
     unsigned endNewIndex = 0;
     for (unsigned i = 1; i < contents.size(); ++i) {
       auto bucket = getResultBucket(*contents[i], hasRequiredTypes);
-      if (bucket < best) {
-        // This algorithm assumes we don't have both literal and
-        // literal-type-match at the start of the list.
-        assert(bucket != ResultBucket::Literal);
+      if (bucket < best && bucket != ResultBucket::Literal) {
         if (isTopNonLiteralResult(*contents[i], best)) {
           beginNewIndex = i;
           endNewIndex = beginNewIndex + 1;
@@ -1157,10 +1154,10 @@ Completion *CompletionBuilder::finish() {
             contextFreeBase.getKind(),
             contextFreeBase.getOpaqueAssociatedKind(), opKind,
             contextFreeBase.getMacroRoles(), contextFreeBase.isSystem(),
-            contextFreeBase.hasAsyncAlternative(),
-            newCompletionString, contextFreeBase.getModuleName(),
+            contextFreeBase.hasAsyncAlternative(), newCompletionString,
+            contextFreeBase.getModuleName(),
             contextFreeBase.getBriefDocComment(),
-            contextFreeBase.getAssociatedUSRs(),
+            contextFreeBase.getAssociatedUSRs(), contextFreeBase.getSwiftUSR(),
             contextFreeBase.getResultType(),
             contextFreeBase.getNotRecommendedReason(),
             contextFreeBase.getDiagnosticSeverity(),
diff --git a/tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.h b/tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.h
index c87aa81efd06c..c83d60e4e662f 100644
--- a/tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.h
+++ b/tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.h
@@ -46,6 +46,7 @@ struct Options {
   bool annotatedDescription = false;
   bool includeObjectLiterals = true;
   bool addCallWithNoDefaultArgs = true;
+  bool verifyUSRToDecl = false;
   unsigned minFuzzyLength = 2;
   unsigned showTopNonLiteralResults = 3;
 
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp b/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp
index 6948e84496955..5e105da6363d4 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp
@@ -564,12 +564,11 @@ struct SwiftASTManager::Implementation {
       std::shared_ptr<SwiftStatistics> Stats,
       std::shared_ptr<RequestTracker> ReqTracker,
       std::shared_ptr<PluginRegistry> Plugins, StringRef SwiftExecutablePath,
-      StringRef RuntimeResourcePath, StringRef DiagnosticDocumentationPath)
+      StringRef RuntimeResourcePath)
       : EditorDocs(EditorDocs), Config(Config), Stats(Stats),
         ReqTracker(ReqTracker), Plugins(Plugins),
         SwiftExecutablePath(SwiftExecutablePath),
         RuntimeResourcePath(RuntimeResourcePath),
-        DiagnosticDocumentationPath(DiagnosticDocumentationPath),
         SessionTimestamp(llvm::sys::toTimeT(std::chrono::system_clock::now())) {
   }
 
@@ -582,7 +581,6 @@ struct SwiftASTManager::Implementation {
   /// Used to find clang relative to it.
   std::string SwiftExecutablePath;
   std::string RuntimeResourcePath;
-  std::string DiagnosticDocumentationPath;
   SourceManager SourceMgr;
   Cache<ASTKey, ASTProducerRef> ASTCache{ "sourcekit.swift.ASTCache" };
   llvm::sys::Mutex CacheMtx;
@@ -668,10 +666,9 @@ SwiftASTManager::SwiftASTManager(
     std::shared_ptr<SwiftStatistics> Stats,
     std::shared_ptr<RequestTracker> ReqTracker,
     std::shared_ptr<PluginRegistry> Plugins, StringRef SwiftExecutablePath,
-    StringRef RuntimeResourcePath, StringRef DiagnosticDocumentationPath)
+    StringRef RuntimeResourcePath)
     : Impl(*new Implementation(EditorDocs, Config, Stats, ReqTracker, Plugins,
-                               SwiftExecutablePath, RuntimeResourcePath,
-                               DiagnosticDocumentationPath)) {}
+                               SwiftExecutablePath, RuntimeResourcePath)) {}
 
 SwiftASTManager::~SwiftASTManager() {
   delete &Impl;
@@ -710,8 +707,8 @@ bool SwiftASTManager::initCompilerInvocation(
     std::string &Error) {
   return ide::initCompilerInvocation(
       Invocation, OrigArgs, Action, Diags, UnresolvedPrimaryFile, FileSystem,
-      Impl.SwiftExecutablePath, Impl.RuntimeResourcePath,
-      Impl.DiagnosticDocumentationPath, Impl.SessionTimestamp, Error);
+      Impl.SwiftExecutablePath, Impl.RuntimeResourcePath, Impl.SessionTimestamp,
+      Error);
 }
 
 bool SwiftASTManager::initCompilerInvocation(
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftASTManager.h b/tools/SourceKit/lib/SwiftLang/SwiftASTManager.h
index cfa63a25f9ec9..10a883a32c1a0 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftASTManager.h
+++ b/tools/SourceKit/lib/SwiftLang/SwiftASTManager.h
@@ -259,8 +259,7 @@ class SwiftASTManager : public std::enable_shared_from_this<SwiftASTManager> {
                            std::shared_ptr<RequestTracker> ReqTracker,
                            std::shared_ptr<swift::PluginRegistry> Plugins,
                            StringRef SwiftExecutablePath,
-                           StringRef RuntimeResourcePath,
-                           StringRef DiagnosticDocumentationPath);
+                           StringRef RuntimeResourcePath);
   ~SwiftASTManager();
 
   SwiftInvocationRef getTypecheckInvocation(ArrayRef<const char *> Args,
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftCompile.cpp b/tools/SourceKit/lib/SwiftLang/SwiftCompile.cpp
index 5255cb4c7dcee..e2c8d680629d2 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftCompile.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftCompile.cpp
@@ -31,10 +31,9 @@ compile::SessionManager::getSession(StringRef name) {
   }
 
   bool inserted = false;
-  std::tie(i, inserted) =
-      sessions.try_emplace(name, std::make_shared<compile::Session>(
-                                     SwiftExecutablePath, RuntimeResourcePath,
-                                     DiagnosticDocumentationPath, Plugins));
+  std::tie(i, inserted) = sessions.try_emplace(
+      name, std::make_shared<compile::Session>(SwiftExecutablePath,
+                                               RuntimeResourcePath, Plugins));
   assert(inserted);
   return i->second;
 }
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftCompletion.cpp b/tools/SourceKit/lib/SwiftLang/SwiftCompletion.cpp
index 778d1bac70a1a..d576410237d6f 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftCompletion.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftCompletion.cpp
@@ -102,6 +102,7 @@ static void swiftCodeCompleteImpl(
   CompletionContext.setIncludeObjectLiterals(opts.includeObjectLiterals);
   CompletionContext.setAddInitsToTopLevel(opts.addInitsToTopLevel);
   CompletionContext.setAddCallWithNoDefaultArgs(opts.addCallWithNoDefaultArgs);
+  CompletionContext.setVerifyUSRToDecl(opts.verifyUSRToDecl);
 
   Lang.performWithParamsToCompletionLikeOperation(
       UnresolvedInputFile, Offset, /*InsertCodeCompletionToken=*/true, Args,
@@ -728,6 +729,7 @@ static void translateCodeCompletionOptions(OptionsDictionary &from,
   static UIdent KeyPopularityBonus("key.codecomplete.sort.popularitybonus");
   static UIdent KeyAnnotatedDescription("key.codecomplete.annotateddescription");
   static UIdent KeyIncludeObjectLiterals("key.codecomplete.includeobjectliterals");
+  static UIdent KeyVerifyUSRToDecl("key.codecomplete.verifyusrtodecl");
 
   from.valueForOption(KeySortByName, to.sortByName);
   from.valueForOption(KeyUseImportDepth, to.useImportDepth);
@@ -753,6 +755,7 @@ static void translateCodeCompletionOptions(OptionsDictionary &from,
   from.valueForOption(KeyTopNonLiteral, to.showTopNonLiteralResults);
   from.valueForOption(KeyAnnotatedDescription, to.annotatedDescription);
   from.valueForOption(KeyIncludeObjectLiterals, to.includeObjectLiterals);
+  from.valueForOption(KeyVerifyUSRToDecl, to.verifyUSRToDecl);
 }
 
 /// Canonicalize a name that is in the format of a reference to a function into
@@ -914,7 +917,8 @@ static void transformAndForwardResults(
             CodeCompletionDiagnosticSeverity::None,
             /*DiagnosticMessage=*/"");
     auto *paren = new (innerSink.allocator) CodeCompletion::SwiftResult(
-        *contextFreeResult, SemanticContextKind::CurrentNominal,
+        *contextFreeResult, /*DeclOrCtx=*/nullptr,
+        SemanticContextKind::CurrentNominal,
         CodeCompletionFlairBit::ExpressionSpecific,
         exactMatch ? exactMatch->getNumBytesToErase() : 0,
         CodeCompletionResultTypeRelation::Unrelated,
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftDocSupport.cpp b/tools/SourceKit/lib/SwiftLang/SwiftDocSupport.cpp
index e7b48b8f502bb..c5d2c5f3b2612 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftDocSupport.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftDocSupport.cpp
@@ -685,6 +685,7 @@ static void reportAvailabilityAttributes(ASTContext &Ctx, const Decl *D,
   static UIdent PlatformOSXAppExt("source.availability.platform.osx_app_extension");
   static UIdent PlatformtvOSAppExt("source.availability.platform.tvos_app_extension");
   static UIdent PlatformWatchOSAppExt("source.availability.platform.watchos_app_extension");
+  static UIdent PlatformFreeBSD("source.availability.platform.freebsd");
   static UIdent PlatformOpenBSD("source.availability.platform.openbsd");
   static UIdent PlatformWindows("source.availability.platform.windows");
   std::vector<SemanticAvailableAttr> Scratch;
@@ -736,6 +737,9 @@ static void reportAvailabilityAttributes(ASTContext &Ctx, const Decl *D,
     case PlatformKind::OpenBSD:
       PlatformUID = PlatformOpenBSD;
       break;
+    case PlatformKind::FreeBSD:
+      PlatformUID = PlatformFreeBSD;
+      break;
     case PlatformKind::Windows:
       PlatformUID = PlatformWindows;
       break;
@@ -1098,7 +1102,7 @@ static bool getModuleInterfaceInfo(ASTContext &Ctx, StringRef ModuleName,
   llvm::raw_svector_ostream OS(Text);
   AnnotatingPrinter Printer(OS);
 
-  printModuleInterface(M, std::nullopt, TraversalOptions, Printer, Options,
+  printModuleInterface(M, /*GroupNames*/ {}, TraversalOptions, Printer, Options,
                        true);
 
   Info.Text = std::string(OS.str());
@@ -1203,21 +1207,24 @@ class SourceDocASTWalker : public SourceEntityWalker {
     return true;
   }
 
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type Ty,
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type Ty,
                           ReferenceMetaData Data) override {
     if (Data.isImplicit || !Range.isValid())
       return true;
     // Ignore things that don't come from this buffer.
-    if (!SM.getRangeForBuffer(BufferID).contains(Range.getStart()))
+    if (!SM.getRangeForBuffer(BufferID).contains(Range.Start))
       return true;
 
-    unsigned StartOffset = getOffset(Range.getStart());
-    References.emplace_back(D, StartOffset, Range.getByteLength(), Ty);
+    CharSourceRange CharRange = Lexer::getCharSourceRangeFromSourceRange(
+        D->getASTContext().SourceMgr, Range);
+
+    unsigned StartOffset = getOffset(CharRange.getStart());
+    References.emplace_back(D, StartOffset, CharRange.getByteLength(), Ty);
     return true;
   }
 
-  bool visitSubscriptReference(ValueDecl *D, CharSourceRange Range,
+  bool visitSubscriptReference(ValueDecl *D, SourceRange Range,
                                ReferenceMetaData Data,
                                bool IsOpenBracket) override {
     // Treat both open and close brackets equally
@@ -1418,7 +1425,8 @@ SwiftLangSupport::findRenameRanges(llvm::MemoryBuffer *InputBuf,
 
 void SwiftLangSupport::findLocalRenameRanges(
     StringRef Filename, unsigned Line, unsigned Column, unsigned Length,
-    ArrayRef<const char *> Args, SourceKitCancellationToken CancellationToken,
+    ArrayRef<const char *> Args, bool CancelOnSubsequentRequest,
+    SourceKitCancellationToken CancellationToken,
     CategorizedRenameRangesReceiver Receiver) {
   using ResultType = CancellableResult<std::vector<CategorizedRenameRanges>>;
   std::string Error;
@@ -1465,8 +1473,8 @@ void SwiftLangSupport::findLocalRenameRanges(
   /// FIXME: When request cancellation is implemented and Xcode adopts it,
   /// don't use 'OncePerASTToken'.
   static const char OncePerASTToken = 0;
-  getASTManager()->processASTAsync(Invok, ASTConsumer, &OncePerASTToken,
-                                   CancellationToken,
+  const void *Once = CancelOnSubsequentRequest ? &OncePerASTToken : nullptr;
+  getASTManager()->processASTAsync(Invok, ASTConsumer, Once, CancellationToken,
                                    llvm::vfs::getRealFileSystem());
 }
 
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp b/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp
index f522acd1cee5b..d0e675693f3ba 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp
@@ -147,19 +147,12 @@ void EditorDiagConsumer::handleDiagnostic(SourceManager &SM,
   if (Info.ID == diag::lex_editor_placeholder.ID ||
       Info.ID == diag::oslog_invalid_log_message.ID)
     return;
-
   bool IsNote = (Info.Kind == DiagnosticKind::Note);
 
   if (IsNote && !haveLastDiag())
     // Is this possible?
     return;
 
-  if (Info.Kind == DiagnosticKind::Remark) {
-    // FIXME: we may want to handle optimization remarks in sourcekitd.
-    LOG_WARN_FUNC("unhandled optimization remark");
-    return;
-  }
-
   DiagnosticEntryInfo SKInfo;
 
   SKInfo.ID = DiagnosticEngine::diagnosticIDStringFor(Info.ID).str();
@@ -237,7 +230,6 @@ void EditorDiagConsumer::handleDiagnostic(SourceManager &SM,
     getLastDiag().Notes.push_back(std::move(SKInfo));
     return;
   }
-
   switch (Info.Kind) {
   case DiagnosticKind::Error:
     SKInfo.Severity = DiagnosticSeverityKind::Error;
@@ -245,8 +237,10 @@ void EditorDiagConsumer::handleDiagnostic(SourceManager &SM,
   case DiagnosticKind::Warning:
     SKInfo.Severity = DiagnosticSeverityKind::Warning;
     break;
-  case DiagnosticKind::Note:
   case DiagnosticKind::Remark:
+    SKInfo.Severity = DiagnosticSeverityKind::Remark;
+    break;
+  case DiagnosticKind::Note:
     llvm_unreachable("already covered");
   }
 
@@ -990,8 +984,8 @@ class SemanticAnnotator : public SourceEntityWalker {
     }
   }
 
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type T,
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type T,
                           ReferenceMetaData Data) override {
     if (Data.isImplicit)
       return true;
@@ -1004,9 +998,12 @@ class SemanticAnnotator : public SourceEntityWalker {
     if (D->isUnavailable())
       return true;
 
+    CharSourceRange CharRange = Lexer::getCharSourceRangeFromSourceRange(
+        D->getASTContext().SourceMgr, Range);
+
     auto &SM = D->getASTContext().SourceMgr;
     if (D == D->getASTContext().getOptionalNoneDecl() &&
-        SM.extractText(Range, BufferID) == "nil") {
+        SM.extractText(CharRange, BufferID) == "nil") {
       // If a 'nil' literal occurs in a swift-case statement, it gets replaced
       // by a reference to 'Optional.none' in the AST. We want to continue
       // highlighting 'nil' as a keyword and not as an enum element.
@@ -1015,11 +1012,11 @@ class SemanticAnnotator : public SourceEntityWalker {
 
     if (CtorTyRef)
       D = CtorTyRef;
-    annotate(D, /*IsRef=*/true, Range);
+    annotate(D, /*IsRef=*/true, CharRange);
     return true;
   }
 
-  bool visitSubscriptReference(ValueDecl *D, CharSourceRange Range,
+  bool visitSubscriptReference(ValueDecl *D, SourceRange Range,
                                ReferenceMetaData Data,
                                bool IsOpenBracket) override {
     // We should treat both open and close brackets equally
@@ -1592,6 +1589,10 @@ class PlaceholderExpansionScanner {
       return MacroWalking::Arguments;
     }
 
+    bool shouldWalkIntoCustomAttrs() const override {
+      return true;
+    }
+
     PreWalkResult<Expr *> walkToExprPre(Expr *E) override {
       if (isa<EditorPlaceholderExpr>(E) && E->getStartLoc() == PlaceholderLoc) {
         Found = cast<EditorPlaceholderExpr>(E);
@@ -1679,34 +1680,65 @@ class PlaceholderExpansionScanner {
     public:
       const SourceManager &SM;
       SourceLoc TargetLoc;
-      std::pair<Expr *, ArgumentList *> EnclosingCallAndArg;
+      std::pair<ASTNode, ArgumentList *> EnclosingCallAndArg;
       Expr *OuterExpr;
       Stmt *OuterStmt;
-      explicit CallExprFinder(const SourceManager &SM)
-        :SM(SM) { }
-
-      bool checkCallExpr(Expr *E) {
-        ArgumentList *Args = nullptr;
-        if (auto *CE = dyn_cast<CallExpr>(E)) {
-          // Call expression can have argument.
-          Args = CE->getArgs();
+      Decl *OuterDecl;
+
+      explicit CallExprFinder(const SourceManager &SM) : SM(SM) {}
+
+      void checkArgumentList(ArgumentList *Args) {
+        ASTNode Enclosing;
+        if (auto *E = Parent.getAsExpr()) {
+          // Must have a function call or macro parent.
+          if (!isa<CallExpr, MacroExpansionExpr>(E) ||
+              E->getArgs() != Args) {
+            return;
+          }
+          // If the outer expression is the call itself, disregard it.
+          if (OuterExpr == E)
+            OuterExpr = nullptr;
+
+          Enclosing = E;
         }
-        if (!Args)
-          return false;
-        if (EnclosingCallAndArg.first)
-          OuterExpr = EnclosingCallAndArg.first;
-        EnclosingCallAndArg = {E, Args};
-        return true;
+        if (auto *D = Parent.getAsDecl()) {
+          // Must have a macro decl parent.
+          auto *MED = dyn_cast<MacroExpansionDecl>(D);
+          if (!MED || MED->getArgs() != Args)
+            return;
+          Enclosing = D;
+        }
+        if (!Enclosing)
+          return;
+
+        // If we have an outer enclosing call, update the outer nodes if needed.
+        if (auto EnclosingCall = EnclosingCallAndArg.first) {
+          if (!OuterExpr)
+            OuterExpr = EnclosingCall.dyn_cast<Expr *>();
+          if (!OuterDecl)
+            OuterDecl = EnclosingCall.dyn_cast<Decl *>();
+        }
+
+        EnclosingCallAndArg = {Enclosing, Args};
       }
 
       MacroWalking getMacroWalkingBehavior() const override {
         return MacroWalking::Arguments;
       }
 
+      PreWalkResult<ArgumentList *>
+      walkToArgumentListPre(ArgumentList *ArgList) override {
+        auto SR = ArgList->getSourceRange();
+        if (SR.isValid() && SM.rangeContainsTokenLoc(SR, TargetLoc))
+          checkArgumentList(ArgList);
+
+        return Action::Continue(ArgList);
+      }
+
       PreWalkResult<Expr *> walkToExprPre(Expr *E) override {
         auto SR = E->getSourceRange();
         if (SR.isValid() && SM.rangeContainsTokenLoc(SR, TargetLoc) &&
-            !checkCallExpr(E) && !EnclosingCallAndArg.first) {
+            !OuterExpr && !EnclosingCallAndArg.first) {
           if (!isa<TryExpr>(E) && !isa<AwaitExpr>(E) && !isa<UnsafeExpr>(E) &&
               !isa<PrefixUnaryExpr>(E)) {
             // We don't want to expand to trailing closures if the call is
@@ -1782,6 +1814,7 @@ class PlaceholderExpansionScanner {
         EnclosingCallAndArg = {nullptr, nullptr};
         OuterExpr = nullptr;
         OuterStmt = nullptr;
+        OuterDecl = nullptr;
         TargetLoc = SL;
         SF.walk(*this);
         return EnclosingCallAndArg.second;
@@ -1791,14 +1824,9 @@ class PlaceholderExpansionScanner {
     CallExprFinder CEFinder(SM);
     auto *Args = CEFinder.findEnclosingCallArg(SF, SL);
 
-    if (!Args)
-      return std::make_pair(Args, false);
-    if (CEFinder.OuterExpr)
-      return std::make_pair(Args, false);
-    if (CEFinder.OuterStmt)
-      return std::make_pair(Args, false);
-
-    return std::make_pair(Args, true);
+    auto HasOuterNode =
+        CEFinder.OuterExpr || CEFinder.OuterStmt || CEFinder.OuterDecl;
+    return std::make_pair(Args, /*useTrailingClosure*/ Args && !HasOuterNode);
   }
 
   struct ParamClosureInfo {
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftEditorInterfaceGen.cpp b/tools/SourceKit/lib/SwiftLang/SwiftEditorInterfaceGen.cpp
index 7cfb02d6f1136..20562beeda137 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftEditorInterfaceGen.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftEditorInterfaceGen.cpp
@@ -387,8 +387,11 @@ static bool getModuleInterfaceInfo(
       Options.SkipInlineCXXNamespace = true;
     }
   }
+  // Skip submodules but include any exported modules that have the same public
+  // module name as this module.
   ModuleTraversalOptions TraversalOptions =
-      std::nullopt; // Don't print submodules.
+      ModuleTraversal::VisitMatchingExported;
+
   SmallString<128> Text;
   llvm::raw_svector_ostream OS(Text);
   AnnotatingPrinter Printer(Info, OS);
@@ -787,26 +790,8 @@ void SwiftLangSupport::editorOpenInterface(
                                                       SynthesizedExtensions,
                                                       InterestedUSR);
   if (!IFaceGenRef) {
-      // Retry to generate a module interface with C++ interop enabled,
-      // if the first attempt failed.
-      bool retryWithCxxEnabled = true;
-      for (const auto &arg: Args) {
-          if (StringRef(arg).starts_with("-cxx-interoperability-mode=") ||
-              StringRef(arg).starts_with("-enable-experimental-cxx-interop")) {
-              retryWithCxxEnabled = false;
-              break;
-          }
-      }
-      if (retryWithCxxEnabled) {
-          std::vector<const char *> AdjustedArgs(Args.begin(), Args.end());
-          AdjustedArgs.push_back("-cxx-interoperability-mode=default");
-          return editorOpenInterface(Consumer, Name, ModuleName, Group, AdjustedArgs,
-                                     SynthesizedExtensions, InterestedUSR);
-      }
-      else {
-          Consumer.handleRequestError(ErrMsg.c_str());
-          return;
-      }
+    Consumer.handleRequestError(ErrMsg.c_str());
+    return;
   }
 
   IFaceGenRef->reportEditorInfo(Consumer);
@@ -850,6 +835,7 @@ class PrimaryFileInterfaceConsumer : public SwiftASTConsumer {
 
 void SwiftLangSupport::editorOpenSwiftSourceInterface(
     StringRef Name, StringRef SourceName, ArrayRef<const char *> Args,
+    bool CancelOnSubsequentRequest,
     SourceKitCancellationToken CancellationToken,
     std::shared_ptr<EditorConsumer> Consumer) {
   std::string Error;
@@ -861,7 +847,8 @@ void SwiftLangSupport::editorOpenSwiftSourceInterface(
   auto AstConsumer = std::make_shared<PrimaryFileInterfaceConsumer>(Name,
     SourceName, IFaceGenContexts, Consumer, Invocation);
   static const char OncePerASTToken = 0;
-  getASTManager()->processASTAsync(Invocation, AstConsumer, &OncePerASTToken,
+  const void *Once = CancelOnSubsequentRequest ? &OncePerASTToken : nullptr;
+  getASTManager()->processASTAsync(Invocation, AstConsumer, Once,
                                    CancellationToken,
                                    llvm::vfs::getRealFileSystem());
 }
@@ -881,7 +868,7 @@ void SwiftLangSupport::editorOpenHeaderInterface(EditorConsumer &Consumer,
   CompilerInvocation Invocation;
   std::string Error;
 
-  ArrayRef<const char *> SwiftArgs = UsingSwiftArgs ? Args : std::nullopt;
+  auto SwiftArgs = UsingSwiftArgs ? Args : ArrayRef<const char *>();
   if (getASTManager()->initCompilerInvocationNoInputs(
           Invocation, SwiftArgs, FrontendOptions::ActionType::Typecheck,
           CI.getDiags(), Error)) {
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftIndexing.cpp b/tools/SourceKit/lib/SwiftLang/SwiftIndexing.cpp
index 90e8503199328..2c753aa0a0fa2 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftIndexing.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftIndexing.cpp
@@ -403,6 +403,7 @@ static void emitIndexDataForSourceFile(SourceFile &PrimarySourceFile,
                                IndexOpts.IncludeSystemModules,
                                IndexOpts.IgnoreStdlib,
                                IndexOpts.IncludeLocals,
+                               IndexOpts.Compress,
                                isDebugCompilation,
                                IndexOpts.DisableImplicitModules,
                                Invocation.getTargetTriple(),
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp b/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp
index b2a73d14138a9..164e315188af2 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp
@@ -281,7 +281,6 @@ SwiftLangSupport::SwiftLangSupport(SourceKit::Context &SKCtx)
   llvm::SmallString<128> LibPath(SKCtx.getRuntimeLibPath());
   llvm::sys::path::append(LibPath, "swift");
   RuntimeResourcePath = std::string(LibPath.str());
-  DiagnosticDocumentationPath = SKCtx.getDiagnosticDocumentationPath().str();
 
   Stats = std::make_shared<SwiftStatistics>();
   EditorDocuments = std::make_shared<SwiftEditorDocumentFileMap>();
@@ -290,16 +289,14 @@ SwiftLangSupport::SwiftLangSupport(SourceKit::Context &SKCtx)
 
   ASTMgr = std::make_shared<SwiftASTManager>(
       EditorDocuments, SKCtx.getGlobalConfiguration(), Stats, ReqTracker,
-      Plugins, SwiftExecutablePath, RuntimeResourcePath,
-      DiagnosticDocumentationPath);
+      Plugins, SwiftExecutablePath, RuntimeResourcePath);
 
   IDEInspectionInst = std::make_shared<IDEInspectionInstance>(Plugins);
   configureIDEInspectionInstance(IDEInspectionInst,
                                  SKCtx.getGlobalConfiguration());
 
   CompileManager = std::make_shared<compile::SessionManager>(
-      SwiftExecutablePath, RuntimeResourcePath, DiagnosticDocumentationPath,
-      Plugins);
+      SwiftExecutablePath, RuntimeResourcePath, Plugins);
 
   // By default, just use the in-memory cache.
   CCCache->inMemory = std::make_unique<ide::CodeCompletionCache>();
@@ -378,6 +375,10 @@ UIdent SwiftLangSupport::getUIDForAccessor(const ValueDecl *D,
     return IsRef ? KindRefAccessorModify : KindDeclAccessorModify;
   case AccessorKind::Init:
     return IsRef ? KindRefAccessorInit : KindDeclAccessorInit;
+  case AccessorKind::Borrow:
+    return IsRef ? KindRefAccessorBorrow : KindDeclAccessorBorrow;
+  case AccessorKind::Mutate:
+    return IsRef ? KindRefAccessorMutate : KindDeclAccessorMutate;
   }
 
   llvm_unreachable("Unhandled AccessorKind in switch.");
@@ -894,7 +895,8 @@ bool SwiftLangSupport::printDisplayName(const swift::ValueDecl *D,
   if (!D->hasName())
     return true;
 
-  OS << D->getName();
+  D->getName().print(OS, /*skipEmptyArgumentNames*/ false,
+                     /*escapeIfNeeded*/ true);
   return false;
 }
 
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h b/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h
index 9a56d6684c440..172ff53c2e32a 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h
+++ b/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h
@@ -48,6 +48,7 @@ namespace swift {
   class SourceFile;
   class SILOptions;
   class ValueDecl;
+  class ParamDecl;
   class GenericSignature;
   enum class AccessorKind;
 
@@ -283,10 +284,8 @@ class Session {
 public:
   Session(const std::string &SwiftExecutablePath,
           const std::string &RuntimeResourcePath,
-          const std::string &DiagnosticDocumentationPath,
           std::shared_ptr<swift::PluginRegistry> Plugins)
-      : Compiler(SwiftExecutablePath, RuntimeResourcePath,
-                 DiagnosticDocumentationPath, Plugins) {}
+      : Compiler(SwiftExecutablePath, RuntimeResourcePath, Plugins) {}
 
   bool
   performCompile(llvm::ArrayRef<const char *> Args,
@@ -300,7 +299,6 @@ class Session {
 class SessionManager {
   const std::string &SwiftExecutablePath;
   const std::string &RuntimeResourcePath;
-  const std::string &DiagnosticDocumentationPath;
   const std::shared_ptr<swift::PluginRegistry> Plugins;
 
   llvm::StringMap<std::shared_ptr<Session>> sessions;
@@ -311,12 +309,9 @@ class SessionManager {
 public:
   SessionManager(const std::string &SwiftExecutablePath,
                  const std::string &RuntimeResourcePath,
-                 const std::string &DiagnosticDocumentationPath,
                  const std::shared_ptr<swift::PluginRegistry> Plugins)
       : SwiftExecutablePath(SwiftExecutablePath),
-        RuntimeResourcePath(RuntimeResourcePath),
-        DiagnosticDocumentationPath(DiagnosticDocumentationPath),
-        Plugins(Plugins) {}
+        RuntimeResourcePath(RuntimeResourcePath), Plugins(Plugins) {}
 
   std::shared_ptr<Session> getSession(StringRef name);
 
@@ -342,7 +337,6 @@ class SwiftLangSupport : public LangSupport {
   /// Used to find clang relative to it.
   std::string SwiftExecutablePath;
   std::string RuntimeResourcePath;
-  std::string DiagnosticDocumentationPath;
   std::shared_ptr<SwiftASTManager> ASTMgr;
   std::shared_ptr<SwiftEditorDocumentFileMap> EditorDocuments;
   std::shared_ptr<RequestTracker> ReqTracker;
@@ -366,9 +360,6 @@ class SwiftLangSupport : public LangSupport {
   }
 
   StringRef getRuntimeResourcePath() const { return RuntimeResourcePath; }
-  StringRef getDiagnosticDocumentationPath() const {
-    return DiagnosticDocumentationPath;
-  }
 
   std::shared_ptr<SwiftASTManager> getASTManager() { return ASTMgr; }
 
@@ -619,6 +610,7 @@ class SwiftLangSupport : public LangSupport {
 
   void editorOpenSwiftSourceInterface(
       StringRef Name, StringRef SourceName, ArrayRef<const char *> Args,
+      bool CancelOnSubsequentRequest,
       SourceKitCancellationToken CancellationToken,
       std::shared_ptr<EditorConsumer> Consumer) override;
 
@@ -708,6 +700,7 @@ class SwiftLangSupport : public LangSupport {
 
   void findLocalRenameRanges(StringRef Filename, unsigned Line, unsigned Column,
                              unsigned Length, ArrayRef<const char *> Args,
+                             bool CancelOnSubsequentRequest,
                              SourceKitCancellationToken CancellationToken,
                              CategorizedRenameRangesReceiver Receiver) override;
 
@@ -723,6 +716,7 @@ class SwiftLangSupport : public LangSupport {
       StringRef PrimaryFilePath, StringRef InputBufferName,
       ArrayRef<const char *> Args, std::optional<unsigned> Offset,
       std::optional<unsigned> Length, bool FullyQualified,
+      bool CancelOnSubsequentRequest,
       SourceKitCancellationToken CancellationToken,
       std::function<void(const RequestResult<VariableTypesInFile> &)> Receiver)
       override;
@@ -730,6 +724,7 @@ class SwiftLangSupport : public LangSupport {
   void semanticRefactoring(StringRef PrimaryFilePath,
                            SemanticRefactoringInfo Info,
                            ArrayRef<const char *> Args,
+                           bool CancelOnSubsequentRequest,
                            SourceKitCancellationToken CancellationToken,
                            CategorizedEditsReceiver Receiver) override;
 
@@ -762,6 +757,12 @@ class SwiftLangSupport : public LangSupport {
                                ConformingMethodListConsumer &Consumer,
                                std::optional<VFSOptions> vfsOptions) override;
 
+  void getSignatureHelp(StringRef PrimaryFilePath, unsigned Offset,
+                        ArrayRef<const char *> Args,
+                        SourceKitCancellationToken CancellationToken,
+                        SignatureHelpConsumer &Consumer,
+                        std::optional<VFSOptions> vfsOptions) override;
+
   void expandMacroSyntactically(llvm::MemoryBuffer *inputBuf,
                                 ArrayRef<const char *> args,
                                 ArrayRef<MacroExpansionInfo> expansions,
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftSignatureHelp.cpp b/tools/SourceKit/lib/SwiftLang/SwiftSignatureHelp.cpp
new file mode 100644
index 0000000000000..2b5ddb53a5169
--- /dev/null
+++ b/tools/SourceKit/lib/SwiftLang/SwiftSignatureHelp.cpp
@@ -0,0 +1,82 @@
+//===--- SwiftSignatureHelp.cpp -------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "SwiftASTManager.h"
+#include "SwiftLangSupport.h"
+#include "swift/IDE/SignatureHelp.h"
+#include "swift/IDE/SignatureHelpFormatter.h"
+#include "swift/IDETool/IDEInspectionInstance.h"
+
+using namespace SourceKit;
+using namespace swift;
+using namespace ide;
+
+static void deliverResults(SourceKit::SignatureHelpConsumer &SKConsumer,
+                           CancellableResult<SignatureHelpResults> Result) {
+  switch (Result.getKind()) {
+  case CancellableResultKind::Success: {
+    SKConsumer.setReusingASTContext(Result->DidReuseAST);
+
+    if (!Result->Result) {
+      // If we have no results, don't call SKConsumer.handleResult which causes
+      // empty results to be delivered.
+      break;
+    }
+
+    llvm::BumpPtrAllocator Allocator;
+    SignatureHelpFormatter Formatter(Allocator);
+
+    SKConsumer.handleResult(Formatter.format(*Result->Result));
+    break;
+  }
+  case CancellableResultKind::Failure:
+    SKConsumer.failed(Result.getError());
+    break;
+  case CancellableResultKind::Cancelled:
+    SKConsumer.cancelled();
+    break;
+  }
+}
+
+void SwiftLangSupport::getSignatureHelp(
+    StringRef PrimaryFilePath, unsigned Offset, ArrayRef<const char *> Args,
+    SourceKitCancellationToken CancellationToken,
+    SignatureHelpConsumer &SKConsumer, std::optional<VFSOptions> vfsOptions) {
+  std::string error;
+
+  auto fileSystem = getFileSystem(vfsOptions, PrimaryFilePath, error);
+  if (!fileSystem) {
+    return SKConsumer.failed(error);
+  }
+
+  std::string InputFileError;
+  std::unique_ptr<llvm::MemoryBuffer> InputBuffer =
+      getASTManager()->getMemoryBuffer(PrimaryFilePath, fileSystem,
+                                       InputFileError);
+  if (!InputBuffer) {
+    return SKConsumer.failed(InputFileError);
+  }
+
+  performWithParamsToCompletionLikeOperation(
+      InputBuffer.get(), Offset, /*InsertCodeCompletionToken=*/true, Args,
+      fileSystem, CancellationToken,
+      [&](CancellableResult<CompletionLikeOperationParams> ParmsResult) {
+        ParmsResult.mapAsync<SignatureHelpResults>(
+            [&](auto &Params, auto DeliverTransformed) {
+              getIDEInspectionInstance()->signatureHelp(
+                  Params.Invocation, Args, fileSystem, Params.completionBuffer,
+                  Offset, Params.DiagC, Params.CancellationFlag,
+                  DeliverTransformed);
+            },
+            [&](auto Result) { deliverResults(SKConsumer, Result); });
+      });
+}
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp b/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp
index 86c93d40e2850..59957d48df7ad 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp
@@ -26,6 +26,7 @@
 #include "swift/AST/ModuleNameLookup.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/SwiftNameTranslation.h"
+#include "swift/Basic/Assertions.h"
 #include "swift/Basic/SourceManager.h"
 #include "swift/Frontend/Frontend.h"
 #include "swift/Frontend/PrintingDiagnosticConsumer.h"
@@ -48,6 +49,7 @@
 #include "clang/Index/USRGeneration.h"
 #include "clang/Lex/Lexer.h"
 
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/MemoryBuffer.h"
 
 #include <numeric>
@@ -764,7 +766,8 @@ static StringRef getModuleName(const ValueDecl *VD,
   // overlay's declaring module as the owning module.
   if (ModuleDecl *Declaring = MD->getDeclaringModuleIfCrossImportOverlay())
     MD = Declaring;
-  return MD->getNameStr();
+
+  return MD->getPublicModuleName(/*onlyIfImported=*/false).str();
 }
 
 struct DeclInfo {
@@ -876,67 +879,112 @@ static void setLocationInfoForClangNode(ClangNode ClangNode,
   }
 }
 
-static unsigned getCharLength(SourceManager &SM, SourceRange TokenRange) {
-  SourceLoc CharEndLoc = Lexer::getLocForEndOfToken(SM, TokenRange.End);
-  return SM.getByteDistance(TokenRange.Start, CharEndLoc);
+static void setLocationInfoForRange(SourceManager &SM, SourceRange R,
+                                    unsigned BufID,
+                                    LocationInfo &Location,
+                                    bool Presumed = false) {
+  CONDITIONAL_ASSERT(BufID == SM.findBufferContainingLoc(R.Start) &&
+                     "SourceRange R should be in BufID");
+
+  auto CR = Lexer::getCharSourceRangeFromSourceRange(SM, R);
+
+  Location.Filename = SM.getIdentifierForBuffer(BufID);
+  Location.Length = CR.getByteLength();
+  Location.Offset = SM.getLocOffsetInBuffer(CR.getStart(), BufID);
+
+  if (Presumed)
+    std::tie(Location.Line, Location.Column) =
+        SM.getPresumedLineAndColumnForLoc(CR.getStart(), BufID);
+  else
+    std::tie(Location.Line, Location.Column) =
+        SM.getLineAndColumnInBuffer(CR.getStart(), BufID);
 }
 
-static void setLocationInfo(const ValueDecl *VD,
-                            LocationInfo &Location) {
+static LocationInfo getDeclLocationInfo(const ValueDecl *VD) {
+  LocationInfo Location;
   ASTContext &Ctx = VD->getASTContext();
   SourceManager &SM = Ctx.SourceMgr;
-
-  auto ClangNode = VD->getClangNode();
-
-  auto Loc = VD->getLoc(/*SerializedOK=*/true);
-  if (Loc.isValid()) {
-    auto getParameterListRange =
-        [&](const ValueDecl *VD) -> std::optional<unsigned> {
-      if (auto FD = dyn_cast<AbstractFunctionDecl>(VD)) {
-        SourceRange R = FD->getParameterListSourceRange();
-        if (R.isValid())
-          return getCharLength(SM, R);
+  auto *Importer = static_cast<ClangImporter *>(Ctx.getClangModuleLoader());
+
+  if (auto loc = VD->getLoc(/*SerializedOK=*/true)) {
+    // For most cases we just want the range of the name itself; it suffices to
+    // make Range from just Loc because Lexer::getCharSourceRangeFromSourceRange
+    // will grow the range to encompass the end of the token at Loc.
+    SourceRange range = loc;
+
+    // One exception is for functions, where we also want to include the range
+    // of the parameter list.
+    if (auto *FD = dyn_cast<AbstractFunctionDecl>(VD)) {
+      if (auto FDR = FD->getParameterListSourceRange())
+        range = FDR;
+    }
+
+    unsigned bufID = SM.findBufferContainingLoc(range.Start);
+
+    // If this range is from a generated buffer, recursively "unexpand" macros
+    // to chase after where the macro was originally expanded from.
+    //
+    // However, we don't care about certain kinds of generated buffers, so save
+    // the original range and buffer ID so we can set location according to VD.
+    auto VDRange = range;
+    auto VDBufID = bufID;
+    while (auto *info = SM.getGeneratedSourceInfo(bufID)) {
+      switch (info->kind) {
+#define MACRO_ROLE(Name, Description)                                          \
+  case GeneratedSourceInfo::Name##MacroExpansion:
+#include "swift/Basic/MacroRoles.def"
+        if (auto *customAttr = info->attachedMacroCustomAttr)
+          range = customAttr->getRange();
+        else
+          range = ASTNode::getFromOpaqueValue(info->astNode).getSourceRange();
+        bufID = SM.findBufferContainingLoc(range.Start);
+        continue; // Continue while-loop to recursively un-expand macros
+
+      case GeneratedSourceInfo::ReplacedFunctionBody:
+        if (bufID == VDBufID) {
+          // The location was in a temporary source buffer that just contains
+          // the function body, which we created while reusing the ASTContext
+          // for the rest of the file. Set the location so that it maps back to
+          // the original file.
+          setLocationInfoForRange(SM, VDRange, VDBufID, Location,
+                                  /*Presumed=*/true);
+          // Adjust offset according to generated buffer.
+          auto originalLoc = info->originalSourceRange.getStart();
+          auto originalBufID = SM.findBufferContainingLoc(originalLoc);
+          auto generatedLoc = info->generatedSourceRange.getStart();
+          auto generatedBufID = SM.findBufferContainingLoc(generatedLoc);
+          Location.Offset +=
+              SM.getLocOffsetInBuffer(originalLoc, originalBufID) -
+              SM.getLocOffsetInBuffer(generatedLoc, generatedBufID);
+        } else {
+          // We somehow encountered a replaced function body while looking
+          // through other macro expansions. Fall back to setting location based
+          // on VD's original source range because mapping location back to the
+          // original file might be tricky.
+          setLocationInfoForRange(SM, VDRange, VDBufID, Location);
+        }
+        return Location;
+      case GeneratedSourceInfo::AttributeFromClang:
+        // This buffer was generated for an imported ClangNode, so set location
+        // info according to that.
+        if (auto node = info->clangNode)
+          setLocationInfoForClangNode(node, Importer, Location);
+        else
+          setLocationInfoForRange(SM, VDRange, VDBufID, Location);
+        return Location;
+      case GeneratedSourceInfo::DefaultArgument:
+      case GeneratedSourceInfo::PrettyPrinted:
+        setLocationInfoForRange(SM, VDRange, VDBufID, Location);
+        return Location;
       }
-      return std::nullopt;
-    };
-    unsigned NameLen;
-    if (auto SigLen = getParameterListRange(VD)) {
-      NameLen = SigLen.value();
-    } else if (VD->hasName()) {
-      NameLen = VD->getBaseName().userFacingName().size();
-    } else {
-      NameLen = getCharLength(SM, Loc);
+      llvm_unreachable("All switch cases either explicitly continue or return");
     }
 
-    auto [DeclBufID, DeclLoc] =
-        VD->getModuleContext()->getOriginalLocation(Loc);
-    Location.Filename = SM.getIdentifierForBuffer(DeclBufID);
-    Location.Offset = SM.getLocOffsetInBuffer(DeclLoc, DeclBufID);
-    Location.Length = NameLen;
-    std::tie(Location.Line, Location.Column) =
-        SM.getLineAndColumnInBuffer(DeclLoc, DeclBufID);
-    if (auto GeneratedSourceInfo = SM.getGeneratedSourceInfo(DeclBufID)) {
-      if (GeneratedSourceInfo->kind ==
-          GeneratedSourceInfo::ReplacedFunctionBody) {
-        // The location was in a temporary source buffer that just contains the
-        // function body and which we created while reusing the ASTContext for
-        // the rest of the file. Map the location back to the original file.
-        unsigned OriginalBufID = SM.findBufferContainingLoc(
-            GeneratedSourceInfo->originalSourceRange.getStart());
-        auto OriginalStartOffset = SM.getLocOffsetInBuffer(
-            GeneratedSourceInfo->originalSourceRange.getStart(), OriginalBufID);
-        auto GeneratedStartOffset = SM.getLocOffsetInBuffer(
-            GeneratedSourceInfo->generatedSourceRange.getStart(), DeclBufID);
-        Location.Offset += OriginalStartOffset - GeneratedStartOffset;
-        std::tie(Location.Line, Location.Column) =
-            SM.getPresumedLineAndColumnForLoc(DeclLoc, DeclBufID);
-      }
-    }
-  } else if (ClangNode) {
-    ClangImporter *Importer =
-        static_cast<ClangImporter*>(Ctx.getClangModuleLoader());
-    setLocationInfoForClangNode(ClangNode, Importer, Location);
+    setLocationInfoForRange(SM, range, bufID, Location);
+  } else if (auto CNode = VD->getClangNode()) {
+    setLocationInfoForClangNode(CNode, Importer, Location);
   }
+  return Location;
 }
 
 static llvm::Error
@@ -1095,7 +1143,7 @@ fillSymbolInfo(CursorSymbolInfo &Symbol, const DeclInfo &DInfo,
           Lang.getIFaceGenContexts().find(Symbol.ModuleName, Invoc))
     Symbol.ModuleInterfaceName = IFaceGenRef->getDocumentName();
 
-  setLocationInfo(DInfo.OriginalProperty, Symbol.Location);
+  Symbol.Location = getDeclLocationInfo(DInfo.OriginalProperty);
   if (!Symbol.Location.Filename.empty()) {
     mapLocToLatestSnapshot(Lang, Symbol.Location, PreviousSnaps);
     if (Symbol.Location.Filename.empty()) {
@@ -1115,7 +1163,7 @@ fillSymbolInfo(CursorSymbolInfo &Symbol, const DeclInfo &DInfo,
             return;
         } else {
           if (clang::index::generateUSRForDecl(
-                  D.get<const clang::NamedDecl *>(), Buffer))
+                  cast<const clang::NamedDecl *>(D), Buffer))
             return;
         }
         Strings.push_back(copyAndClearString(Allocator, Buffer));
@@ -2775,7 +2823,8 @@ static RefactoringKind getIDERefactoringKind(SemanticRefactoringInfo Info) {
 
 void SwiftLangSupport::semanticRefactoring(
     StringRef PrimaryFilePath, SemanticRefactoringInfo Info,
-    ArrayRef<const char *> Args, SourceKitCancellationToken CancellationToken,
+    ArrayRef<const char *> Args, bool CancelOnSubsequentRequest,
+    SourceKitCancellationToken CancellationToken,
     CategorizedEditsReceiver Receiver) {
   std::string Error;
   SwiftInvocationRef Invok =
@@ -2833,7 +2882,8 @@ void SwiftLangSupport::semanticRefactoring(
   /// FIXME: When request cancellation is implemented and Xcode adopts it,
   /// don't use 'OncePerASTToken'.
   static const char OncePerASTToken = 0;
-  getASTManager()->processASTAsync(Invok, std::move(Consumer), &OncePerASTToken,
+  const void *Once = CancelOnSubsequentRequest ? &OncePerASTToken : nullptr;
+  getASTManager()->processASTAsync(Invok, std::move(Consumer), Once,
                                    CancellationToken,
                                    llvm::vfs::getRealFileSystem());
 }
@@ -2917,6 +2967,7 @@ void SwiftLangSupport::collectVariableTypes(
     StringRef PrimaryFilePath, StringRef InputBufferName,
     ArrayRef<const char *> Args, std::optional<unsigned> Offset,
     std::optional<unsigned> Length, bool FullyQualified,
+    bool CancelOnSubsequentRequest,
     SourceKitCancellationToken CancellationToken,
     std::function<void(const RequestResult<VariableTypesInFile> &)> Receiver) {
   std::string Error;
@@ -2996,7 +3047,8 @@ void SwiftLangSupport::collectVariableTypes(
   /// FIXME: When request cancellation is implemented and Xcode adopts it,
   /// don't use 'OncePerASTToken'.
   static const char OncePerASTToken = 0;
-  getASTManager()->processASTAsync(Invok, std::move(Collector),
-                                   &OncePerASTToken, CancellationToken,
+  const void *Once = CancelOnSubsequentRequest ? &OncePerASTToken : nullptr;
+  getASTManager()->processASTAsync(Invok, std::move(Collector), Once,
+                                   CancellationToken,
                                    llvm::vfs::getRealFileSystem());
 }
diff --git a/tools/SourceKit/tools/complete-test/complete-test.cpp b/tools/SourceKit/tools/complete-test/complete-test.cpp
index bb225cafa1a14..1df3880b051a1 100644
--- a/tools/SourceKit/tools/complete-test/complete-test.cpp
+++ b/tools/SourceKit/tools/complete-test/complete-test.cpp
@@ -64,6 +64,7 @@ struct TestOptions {
   std::optional<bool> fuzzyMatching;
   std::optional<unsigned> fuzzyWeight;
   std::optional<unsigned> popularityBonus;
+  std::optional<bool> verifyUSRToDecl;
   StringRef filterRulesJSON;
   std::string moduleCachePath;
   bool rawOutput = false;
@@ -115,6 +116,7 @@ static sourcekitd_uid_t KeyResults;
 static sourcekitd_uid_t KeyPopular;
 static sourcekitd_uid_t KeyUnpopular;
 static sourcekitd_uid_t KeySubStructure;
+static sourcekitd_uid_t KeyVerifyUSRToDecl;
 
 // Returns false and sets 'error' on failure.
 static bool parseOptions(ArrayRef<const char *> args, TestOptions &options,
@@ -260,6 +262,10 @@ static bool parseOptions(ArrayRef<const char *> args, TestOptions &options,
       options.disableImplicitConcurrencyModuleImport = true;
     } else if (opt == "disable-implicit-string-processing-module-import") {
       options.disableImplicitStringProcessingModuleImport = true;
+    } else if (opt == "verify-usr-to-decl") {
+      options.verifyUSRToDecl = true;
+    } else if (opt == "no-verify-usr-to-decl") {
+      options.verifyUSRToDecl = false;
     }
   }
 
@@ -342,6 +348,8 @@ static int skt_main(int argc, const char **argv) {
       sourcekitd_uid_get_from_cstr("key.codecomplete.sort.popularitybonus");
   KeyTopNonLiteral =
       sourcekitd_uid_get_from_cstr("key.codecomplete.showtopnonliteralresults");
+  KeyVerifyUSRToDecl =
+      sourcekitd_uid_get_from_cstr("key.codecomplete.verifyusrtodecl");
   KeySourceFile = sourcekitd_uid_get_from_cstr("key.sourcefile");
   KeySourceText = sourcekitd_uid_get_from_cstr("key.sourcetext");
   KeyName = sourcekitd_uid_get_from_cstr("key.name");
@@ -360,6 +368,8 @@ static int skt_main(int argc, const char **argv) {
 
   auto Args = llvm::ArrayRef(argv + 1, argc - 1);
   TestOptions options;
+  // Default to verifying USR to Decl reconstruction.
+  options.verifyUSRToDecl = true;
   std::string error;
   if (!parseOptions(Args, options, error)) {
     llvm::errs() << "usage: complete-test -tok=A file\n" << error << "\n";
@@ -640,6 +650,7 @@ static bool codeCompleteRequest(sourcekitd_uid_t requestUID, const char *name,
     addBoolOption(KeyFuzzyMatching, options.fuzzyMatching);
     addBoolOption(KeyHideLowPriority, options.hideLowPriority);
     addBoolOption(KeyHideByName, options.hideByName);
+    addBoolOption(KeyVerifyUSRToDecl, options.verifyUSRToDecl);
 
     auto addIntOption = [&](sourcekitd_uid_t key,
                             std::optional<unsigned> option) {
diff --git a/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp b/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp
index 14345dfbb40f6..f17962bfce1eb 100644
--- a/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp
+++ b/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp
@@ -35,13 +35,13 @@ enum Opt {
 #undef OPTION
 };
 
-// Create prefix string literals used in Options.td.
-#define PREFIX(NAME, VALUE)                                                    \
-  constexpr llvm::StringLiteral NAME##_init[] = VALUE;                         \
-  constexpr llvm::ArrayRef<llvm::StringLiteral> NAME(                          \
-      NAME##_init, std::size(NAME##_init) - 1);
+#define OPTTABLE_STR_TABLE_CODE
 #include "Options.inc"
-#undef PREFIX
+#undef OPTTABLE_STR_TABLE_CODE
+
+#define OPTTABLE_PREFIXES_TABLE_CODE
+#include "Options.inc"
+#undef OPTTABLE_PREFIXES_TABLE_CODE
 
 // Create table mapping all options defined in Options.td.
 static const llvm::opt::OptTable::Info InfoTable[] = {
@@ -53,7 +53,8 @@ static const llvm::opt::OptTable::Info InfoTable[] = {
 // Create OptTable class for parsing actual command line arguments
 class TestOptTable : public llvm::opt::GenericOptTable {
 public:
-  TestOptTable() : GenericOptTable(InfoTable) {}
+  TestOptTable()
+      : GenericOptTable(OptionStrTable, OptionPrefixesTable, InfoTable) {}
 };
 
 } // end anonymous namespace
@@ -116,6 +117,7 @@ bool TestOptions::parseArgs(llvm::ArrayRef<const char *> Args) {
         .Case("complete.setpopularapi", SourceKitRequest::CodeCompleteSetPopularAPI)
         .Case("typecontextinfo", SourceKitRequest::TypeContextInfo)
         .Case("conformingmethods", SourceKitRequest::ConformingMethodList)
+        .Case("signaturehelp", SourceKitRequest::SignatureHelp)
         .Case("cursor", SourceKitRequest::CursorInfo)
         .Case("related-idents", SourceKitRequest::RelatedIdents)
         .Case("active-regions", SourceKitRequest::ActiveRegions)
@@ -173,6 +175,7 @@ bool TestOptions::parseArgs(llvm::ArrayRef<const char *> Args) {
                      << "- complete.setpopularapi\n"
                      << "- typecontextinfo\n"
                      << "- conformingmethods\n"
+                     << "- signaturehelp\n"
                      << "- cursor\n"
                      << "- related-idents\n"
                      << "- syntax-map\n"
diff --git a/tools/SourceKit/tools/sourcekitd-test/TestOptions.h b/tools/SourceKit/tools/sourcekitd-test/TestOptions.h
index a962e3128253c..ae641fbe24f3b 100644
--- a/tools/SourceKit/tools/sourcekitd-test/TestOptions.h
+++ b/tools/SourceKit/tools/sourcekitd-test/TestOptions.h
@@ -35,6 +35,7 @@ enum class SourceKitRequest {
   CodeCompleteSetPopularAPI,
   TypeContextInfo,
   ConformingMethodList,
+  SignatureHelp,
   ActiveRegions,
   CursorInfo,
   RangeInfo,
diff --git a/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp b/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp
index c79a8f297c03e..e57b3eeb6dc88 100644
--- a/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp
+++ b/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp
@@ -734,6 +734,9 @@ static int handleTestInvocation(TestOptions Opts, TestOptions &InitOpts) {
     sourcekitd_request_dictionary_set_string(Req, KeyName, SemaName.c_str());
     // Default to sort by name.
     Opts.RequestOptions.insert(Opts.RequestOptions.begin(), "sort.byname=1");
+    // Default to verifying USR to Decl conversion to cover many use cases
+    Opts.RequestOptions.insert(Opts.RequestOptions.begin(),
+                               "verifyusrtodecl=1");
     addRequestOptions(Req, Opts, KeyCodeCompleteOptions, "key.codecomplete.");
     break;
 
@@ -817,6 +820,12 @@ static int handleTestInvocation(TestOptions Opts, TestOptions &InitOpts) {
     addRequestOptionsDirect(Req, Opts);
     break;
 
+  case SourceKitRequest::SignatureHelp:
+    sourcekitd_request_dictionary_set_uid(Req, KeyRequest,
+                                          RequestSignatureHelp);
+    sourcekitd_request_dictionary_set_int64(Req, KeyOffset, ByteOffset);
+    break;
+
   case SourceKitRequest::CursorInfo:
     sourcekitd_request_dictionary_set_uid(Req, KeyRequest, RequestCursorInfo);
     if (Opts.CollectActionables) {
@@ -1416,6 +1425,7 @@ static bool handleResponse(sourcekitd_response_t Resp, const TestOptions &Opts,
     case SourceKitRequest::CodeCompleteSetPopularAPI:
     case SourceKitRequest::TypeContextInfo:
     case SourceKitRequest::ConformingMethodList:
+    case SourceKitRequest::SignatureHelp:
     case SourceKitRequest::DependencyUpdated:
     case SourceKitRequest::Diagnostics:
     case SourceKitRequest::SemanticTokens:
diff --git a/tools/SourceKit/tools/sourcekitd/bin/InProc/CodeCompletionSwiftInterop.cpp b/tools/SourceKit/tools/sourcekitd/bin/InProc/CodeCompletionSwiftInterop.cpp
index 106361e973ac6..bbca01be8ae67 100644
--- a/tools/SourceKit/tools/sourcekitd/bin/InProc/CodeCompletionSwiftInterop.cpp
+++ b/tools/SourceKit/tools/sourcekitd/bin/InProc/CodeCompletionSwiftInterop.cpp
@@ -75,7 +75,6 @@ class Connection {
   std::shared_ptr<CodeCompletionCache> completionCache;
   std::string swiftExecutablePath;
   std::string runtimeResourcePath;
-  std::string diagnosticsDocumentationPath;
   std::shared_ptr<SourceKit::RequestTracker> requestTracker;
 
 public:
@@ -87,7 +86,6 @@ class Connection {
         completionCache(std::make_shared<CodeCompletionCache>()),
         swiftExecutablePath(getSwiftExecutablePath()),
         runtimeResourcePath(getRuntimeResourcesPath()),
-        diagnosticsDocumentationPath(getDiagnosticDocumentationPath()),
         requestTracker(new SourceKit::RequestTracker()),
         sessionTimestamp(llvm::sys::toTimeT(std::chrono::system_clock::now())) {
     if (ideInspectionInstance == nullptr) {
@@ -214,6 +212,7 @@ struct CompletionRequest {
   bool includeObjectLiterals = true;
   bool addInitsToTopLevel = false;
   bool addCallWithNoDefaultArgs = true;
+  bool verifyUSRToDecl = false;
 
   CompletionRequest(const char *path, unsigned offset,
                     ArrayRef<const char *> args) {
@@ -296,6 +295,7 @@ swiftide_complete_cancellable(swiftide_connection_t _conn,
   result->context.setIncludeObjectLiterals(req.includeObjectLiterals);
   result->context.setAddInitsToTopLevel(req.addInitsToTopLevel);
   result->context.setAddCallWithNoDefaultArgs(req.addCallWithNoDefaultArgs);
+  result->context.setVerifyUSRToDecl(req.verifyUSRToDecl);
 
   conn->codeComplete(
       req.path, req.offset, req.compilerArguments, fileSystem, result->context,
@@ -371,8 +371,8 @@ void Connection::codeComplete(
   std::string compilerInvocationError;
   bool creatingInvocationFailed = initCompilerInvocation(
       invocation, args, FrontendOptions::ActionType::Typecheck, diags, path,
-      fileSystem, swiftExecutablePath, runtimeResourcePath,
-      diagnosticsDocumentationPath, sessionTimestamp, compilerInvocationError);
+      fileSystem, swiftExecutablePath, runtimeResourcePath, sessionTimestamp,
+      compilerInvocationError);
   if (creatingInvocationFailed) {
     callback(ResultType::failure(compilerInvocationError));
     return;
@@ -491,6 +491,8 @@ swiftide_completion_result_get_kind(swiftide_completion_response_t _response) {
     return SWIFTIDE_COMPLETION_KIND_NONE;
   case CompletionKind::Import:
     return SWIFTIDE_COMPLETION_KIND_IMPORT;
+  case CompletionKind::Using:
+    return SWIFTIDE_COMPLETION_KIND_USING;
   case CompletionKind::UnresolvedMember:
     return SWIFTIDE_COMPLETION_KIND_UNRESOLVEDMEMBER;
   case CompletionKind::DotExpr:
@@ -661,6 +663,42 @@ void swiftide_completion_item_get_doc_brief(
   handler(item.getBriefDocComment().data());
 }
 
+void swiftide_completion_item_get_doc_full_as_xml(
+    swiftide_completion_response_t _response, swiftide_completion_item_t _item,
+    void (^handler)(const char *)) {
+  auto &response = *static_cast<CompletionResult *>(_response);
+  auto &item = *static_cast<CodeCompletionResult *>(_item);
+
+  response.scratch.clear();
+  {
+    llvm::raw_svector_ostream OS(response.scratch);
+    item.printFullDocCommentAsXML(OS);
+  }
+
+  if (response.scratch.empty()) {
+    return handler(nullptr);
+  }
+  handler(response.scratch.c_str());
+}
+
+void swiftide_completion_item_get_doc_raw(
+    swiftide_completion_response_t _response, swiftide_completion_item_t _item,
+    void (^handler)(const char *)) {
+  auto &response = *static_cast<CompletionResult *>(_response);
+  auto &item = *static_cast<CodeCompletionResult *>(_item);
+
+  response.scratch.clear();
+  {
+    llvm::raw_svector_ostream OS(response.scratch);
+    item.printRawDocComment(OS);
+  }
+
+  if (response.scratch.empty()) {
+    return handler(nullptr);
+  }
+  handler(response.scratch.c_str());
+}
+
 void swiftide_completion_item_get_associated_usrs(
     swiftide_completion_response_t _response, swiftide_completion_item_t _item,
     void (^handler)(const char **, uint64_t)) {
diff --git a/tools/SourceKit/tools/sourcekitd/bin/InProc/CodeCompletionSwiftInterop.h b/tools/SourceKit/tools/sourcekitd/bin/InProc/CodeCompletionSwiftInterop.h
index a3b5f1aa7e4f3..2b6ea20507ee9 100644
--- a/tools/SourceKit/tools/sourcekitd/bin/InProc/CodeCompletionSwiftInterop.h
+++ b/tools/SourceKit/tools/sourcekitd/bin/InProc/CodeCompletionSwiftInterop.h
@@ -123,6 +123,7 @@ typedef enum swiftide_completion_kind_t: uint32_t {
   SWIFTIDE_COMPLETION_KIND_TYPEPOSSIBLEFUNCTIONPARAMBEGINNING = 42,
   SWIFTIDE_COMPLETION_KIND_TYPEATTRINHERITANCEBEGINNING = 43,
   SWIFTIDE_COMPLETION_KIND_TYPESIMPLEINVERTED = 44,
+  SWIFTIDE_COMPLETION_KIND_USING = 45,
 } swiftide_completion_kind_t;
 
 typedef enum swiftide_completion_item_kind_t: uint32_t {
@@ -346,6 +347,16 @@ swiftide_completion_item_get_doc_brief(swiftide_completion_response_t,
                                        swiftide_completion_item_t,
                                        void (^handler)(const char *));
 
+SWIFTIDE_PUBLIC void
+swiftide_completion_item_get_doc_full_as_xml(swiftide_completion_response_t,
+                                             swiftide_completion_item_t,
+                                             void (^handler)(const char *));
+
+SWIFTIDE_PUBLIC void
+swiftide_completion_item_get_doc_raw(swiftide_completion_response_t,
+                                     swiftide_completion_item_t,
+                                     void (^handler)(const char *));
+
 SWIFTIDE_PUBLIC void swiftide_completion_item_get_associated_usrs(
     swiftide_completion_response_t, swiftide_completion_item_t,
     void (^handler)(const char **, uint64_t));
diff --git a/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc-darwin.exports b/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc-darwin.exports
index f84b2d1304579..c22cb61f796c1 100644
--- a/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc-darwin.exports
+++ b/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc-darwin.exports
@@ -149,6 +149,8 @@ swiftide_completion_item_get_associated_kind
 swiftide_completion_item_get_associated_usrs
 swiftide_completion_item_get_diagnostic
 swiftide_completion_item_get_doc_brief
+swiftide_completion_item_get_doc_full_as_xml
+swiftide_completion_item_get_doc_raw
 swiftide_completion_item_get_flair
 swiftide_completion_item_get_kind
 swiftide_completion_item_get_label
@@ -193,7 +195,7 @@ _ZN10sourcekitd13handleRequestEPvPKvNSt3__18functionIFvS0_EEE
 _ZN10sourcekitd16requestIsBarrierEPv
 _ZN10sourcekitd23requestIsEnableBarriersEPv
 _ZN10sourcekitd27sendBarriersEnabledResponseENSt3__18functionIFvPvEEE
-_ZN10sourcekitd17initializeServiceEN4llvm9StringRefES1_S1_NSt3__18functionIFvPvEEE
+_ZN10sourcekitd17initializeServiceEN4llvm9StringRefES1_NSt3__18functionIFvPvEEE
 _ZN10sourcekitd24createErrorRequestFailedEN4llvm9StringRefE
 _ZN10sourcekitd24disposeCancellationTokenEPKv
 _ZN10sourcekitd11loadPluginsEN4llvm8ArrayRefINSt3__112basic_stringIcNS2_11char_traitsIcEENS2_9allocatorIcEEEEEERNS_16PluginInitParamsE
diff --git a/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc.cpp b/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc.cpp
index 3b6a6fa0a1655..f1d974953f985 100644
--- a/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc.cpp
+++ b/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc.cpp
@@ -98,13 +98,6 @@ std::string sourcekitdInProc::getSwiftExecutablePath() {
   return path.str().str();
 }
 
-std::string sourcekitdInProc::getDiagnosticDocumentationPath() {
-  llvm::SmallString<128> docPath;
-  getToolchainPrefixPath(docPath);
-  llvm::sys::path::append(docPath, "share", "doc", "swift", "diagnostics");
-  return docPath.str().str();
-}
-
 static std::vector<std::string> registeredPlugins;
 
 void sourcekitd_load_client_plugins(void) {
@@ -117,10 +110,9 @@ void sourcekitd_initialize(void) {
                                    "sourcekitdInProc.msgHandlingQueue");
   if (sourcekitd::initializeClient()) {
     LOG_INFO_FUNC(High, "initializing");
-    sourcekitd::initializeService(
-        sourcekitdInProc::getSwiftExecutablePath(),
-        sourcekitdInProc::getRuntimeLibPath(),
-        sourcekitdInProc::getDiagnosticDocumentationPath(), postNotification);
+    sourcekitd::initializeService(sourcekitdInProc::getSwiftExecutablePath(),
+                                  sourcekitdInProc::getRuntimeLibPath(),
+                                  postNotification);
     static std::once_flag flag;
     std::call_once(flag, [] {
       sourcekitd::PluginInitParams pluginParams(
diff --git a/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc.exports b/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc.exports
index d4f811ed11db4..ed1765152d5e0 100644
--- a/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc.exports
+++ b/tools/SourceKit/tools/sourcekitd/bin/InProc/sourcekitdInProc.exports
@@ -149,6 +149,8 @@ swiftide_completion_item_get_associated_kind
 swiftide_completion_item_get_associated_usrs
 swiftide_completion_item_get_diagnostic
 swiftide_completion_item_get_doc_brief
+swiftide_completion_item_get_doc_full_as_xml
+swiftide_completion_item_get_doc_raw
 swiftide_completion_item_get_flair
 swiftide_completion_item_get_kind
 swiftide_completion_item_get_label
diff --git a/tools/SourceKit/tools/sourcekitd/bin/XPC/Service/XPCService.cpp b/tools/SourceKit/tools/sourcekitd/bin/XPC/Service/XPCService.cpp
index bfbb5801abfe0..3c672ad6e9521 100644
--- a/tools/SourceKit/tools/sourcekitd/bin/XPC/Service/XPCService.cpp
+++ b/tools/SourceKit/tools/sourcekitd/bin/XPC/Service/XPCService.cpp
@@ -225,13 +225,6 @@ static std::string getSwiftExecutablePath() {
   return path.str().str();
 }
 
-static std::string getDiagnosticDocumentationPath() {
-  llvm::SmallString<128> path;
-  getToolchainPrefixPath(path);
-  llvm::sys::path::append(path, "share", "doc", "swift", "diagnostics");
-  return path.str().str();
-}
-
 static dispatch_queue_t msgHandlingQueue;
 static dispatch_queue_t requestQueue;
 
@@ -415,7 +408,6 @@ int main(int argc, const char *argv[]) {
         return xpcUIdentFromSKDUID(uid).c_str();
       });
   sourcekitd::initializeService(getSwiftExecutablePath(), getRuntimeLibPath(),
-                                getDiagnosticDocumentationPath(),
                                 postNotification);
 
   // Increase the file descriptor limit.
diff --git a/tools/SourceKit/tools/sourcekitd/include/sourcekitd/Service.h b/tools/SourceKit/tools/sourcekitd/include/sourcekitd/Service.h
index 141c24f0e2462..5c85fdce17ca7 100644
--- a/tools/SourceKit/tools/sourcekitd/include/sourcekitd/Service.h
+++ b/tools/SourceKit/tools/sourcekitd/include/sourcekitd/Service.h
@@ -27,11 +27,9 @@ using SourceKit::SourceKitCancellationToken;
 /// \param swiftExecutablePath The path of the swift-frontend executable.
 ///                            Used to find clang relative to it.
 /// \param runtimeLibPath The path to the toolchain's library directory.
-/// \param diagnosticDocumentationPath The path to diagnostics documentation.
 /// \param postNotification Callback to post a notification.
 void initializeService(
     llvm::StringRef swiftExecutablePath, llvm::StringRef runtimeLibPath,
-    llvm::StringRef diagnosticDocumentationPath,
     std::function<void(sourcekitd_response_t)> postNotification);
 /// Shutdown the service.
 void shutdownService();
diff --git a/tools/SourceKit/tools/sourcekitd/include/sourcekitd/sourcekitdInProc-Internal.h b/tools/SourceKit/tools/sourcekitd/include/sourcekitd/sourcekitdInProc-Internal.h
index 08cc5a5f4080c..d9199381dd2a7 100644
--- a/tools/SourceKit/tools/sourcekitd/include/sourcekitd/sourcekitdInProc-Internal.h
+++ b/tools/SourceKit/tools/sourcekitd/include/sourcekitd/sourcekitdInProc-Internal.h
@@ -18,7 +18,6 @@
 namespace sourcekitdInProc {
 std::string getRuntimeLibPath();
 std::string getSwiftExecutablePath();
-std::string getDiagnosticDocumentationPath();
 } // namespace sourcekitdInProc
 
 #endif
diff --git a/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp b/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp
index c3e802a5c056f..3138558df83d9 100644
--- a/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp
+++ b/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp
@@ -36,6 +36,7 @@
 #include "swift/Basic/LLVMInitialize.h"
 #include "swift/Basic/Statistic.h"
 #include "swift/Basic/Version.h"
+#include "swift/IDE/SignatureHelpFormatter.h"
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
@@ -162,16 +163,15 @@ static Statistic numSemaRequests(UIdentFromSKDUID(KindStatNumSemaRequests),
 
 void sourcekitd::initializeService(
     llvm::StringRef swiftExecutablePath, StringRef runtimeLibPath,
-    StringRef diagnosticDocumentationPath,
     std::function<void(sourcekitd_response_t)> postNotification) {
   INITIALIZE_LLVM();
   initializeSwiftModules();
   llvm::EnablePrettyStackTrace();
-  GlobalCtx = new SourceKit::Context(
-      swiftExecutablePath, runtimeLibPath, diagnosticDocumentationPath,
-      SourceKit::createSwiftLangSupport, [](SourceKit::Context &Ctx) {
-        return std::make_shared<PluginSupport>();
-      });
+  GlobalCtx = new SourceKit::Context(swiftExecutablePath, runtimeLibPath,
+                                     SourceKit::createSwiftLangSupport,
+                                     [](SourceKit::Context &Ctx) {
+                                       return std::make_shared<PluginSupport>();
+                                     });
   auto noteCenter = GlobalCtx->getNotificationCenter();
 
   noteCenter->addDocumentUpdateNotificationReceiver([postNotification](StringRef DocumentName) {
@@ -312,6 +312,11 @@ static sourcekitd_response_t conformingMethodList(
     ArrayRef<const char *> ExpectedTypes, std::optional<VFSOptions> vfsOptions,
     SourceKitCancellationToken CancellationToken);
 
+static sourcekitd_response_t
+signatureHelp(StringRef PrimaryFilePath, int64_t Offset,
+              ArrayRef<const char *> Args, std::optional<VFSOptions> vfsOptions,
+              SourceKitCancellationToken CancellationToken);
+
 static sourcekitd_response_t editorOpen(StringRef Name, llvm::MemoryBuffer *Buf,
                                         SKEditorConsumerOptions Opts,
                                         ArrayRef<const char *> Args,
@@ -331,6 +336,7 @@ editorOpenHeaderInterface(StringRef Name, StringRef HeaderName,
 static void
 editorOpenSwiftSourceInterface(StringRef Name, StringRef SourceName,
                                ArrayRef<const char *> Args,
+                               bool CancelOnSubsequentRequest,
                                SourceKitCancellationToken CancellationToken,
                                ResponseReceiver Rec, bool EnableDeclarations);
 
@@ -1053,8 +1059,13 @@ static void handleRequestEditorOpenSwiftSourceInterface(
     // Reporting the declarations array is off by default
     bool EnableDeclarations =
         Req.getOptionalInt64(KeyEnableDeclarations).value_or(false);
+    // For backwards compatibility, the default is 1.
+    int64_t CancelOnSubsequentRequest = 1;
+    Req.getInt64(KeyCancelOnSubsequentRequest, CancelOnSubsequentRequest,
+                 /*isOptional=*/true);
     return editorOpenSwiftSourceInterface(
-        *Name, *FileName, Args, CancellationToken, Rec, EnableDeclarations);
+        *Name, *FileName, Args, CancelOnSubsequentRequest, CancellationToken,
+        Rec, EnableDeclarations);
   }
 }
 
@@ -1467,6 +1478,35 @@ handleRequestConformingMethodList(const RequestDict &Req,
   });
 }
 
+static void
+handleRequestSignatureHelp(const RequestDict &Req,
+                           SourceKitCancellationToken CancellationToken,
+                           ResponseReceiver Rec) {
+  handleSemanticRequest(Req, Rec, [Req, CancellationToken, Rec]() {
+    std::optional<VFSOptions> vfsOptions = getVFSOptions(Req);
+    std::optional<StringRef> PrimaryFilePath =
+        getPrimaryFilePathForRequestOrEmitError(Req, Rec);
+    if (!PrimaryFilePath)
+      return;
+
+    StringRef InputBufferName = getInputBufferNameForRequest(Req, Rec);
+    if (!InputBufferName.empty())
+      return Rec(createErrorRequestInvalid(
+          "'key.primary_file' and 'key.sourcefile' can't be different"));
+
+    SmallVector<const char *, 8> Args;
+    if (getCompilerArgumentsForRequestOrEmitError(Req, Args, Rec))
+      return;
+
+    int64_t Offset;
+    if (Req.getInt64(KeyOffset, Offset, /*isOptional=*/false))
+      return Rec(createErrorRequestInvalid("missing 'key.offset'"));
+
+    return Rec(signatureHelp(*PrimaryFilePath, Offset, Args,
+                             std::move(vfsOptions), CancellationToken));
+  });
+}
+
 static void handleRequestIndex(const RequestDict &Req,
                                SourceKitCancellationToken CancellationToken,
                                ResponseReceiver Rec) {
@@ -1506,6 +1546,10 @@ getIndexStoreOpts(const RequestDict &Req, ResponseReceiver Rec) {
   if (auto IncludeLocals = Req.getOptionalInt64(KeyIncludeLocals)) {
     Opts.IncludeLocals = IncludeLocals.value() > 0;
   }
+  
+  if (auto Compress = Req.getOptionalInt64(KeyCompress)) {
+    Opts.Compress = Compress.value() > 0;
+  }
 
   if (auto IgnoreClangModules = Req.getOptionalInt64(KeyIgnoreClangModules)) {
     Opts.IgnoreClangModules = IgnoreClangModules.value() > 0;
@@ -1705,8 +1749,15 @@ handleRequestSemanticRefactoring(const RequestDict &Req,
         Info.Line = Line;
         Info.Column = Column;
         Info.Length = Length;
+
+        // For backwards compatibility, the default is 1.
+        int64_t CancelOnSubsequentRequest = 1;
+        Req.getInt64(KeyCancelOnSubsequentRequest, CancelOnSubsequentRequest,
+                     /*isOptional=*/true);
+
         return Lang.semanticRefactoring(
-            *PrimaryFilePath, Info, Args, CancellationToken,
+            *PrimaryFilePath, Info, Args, CancelOnSubsequentRequest,
+            CancellationToken,
             [Rec](const RequestResult<ArrayRef<CategorizedEdits>> &Result) {
               Rec(createCategorizedEditsResponse(Result));
             });
@@ -1782,9 +1833,15 @@ handleRequestCollectVariableType(const RequestDict &Req,
                          [](int64_t v) -> unsigned { return v; });
     int64_t FullyQualified = false;
     Req.getInt64(KeyFullyQualified, FullyQualified, /*isOptional=*/true);
+
+    // For backwards compatibility, the default is 1.
+    int64_t CancelOnSubsequentRequest = 1;
+    Req.getInt64(KeyCancelOnSubsequentRequest, CancelOnSubsequentRequest,
+                 /*isOptional=*/true);
+
     return Lang.collectVariableTypes(
         *PrimaryFilePath, InputBufferName, Args, Offset, Length, FullyQualified,
-        CancellationToken,
+        CancelOnSubsequentRequest, CancellationToken,
         [Rec](const RequestResult<VariableTypesInFile> &Result) {
           reportVariableTypeInfo(Result, Rec);
         });
@@ -1814,9 +1871,15 @@ handleRequestFindLocalRenameRanges(const RequestDict &Req,
       return Rec(createErrorRequestInvalid("'key.column' is required"));
     Req.getInt64(KeyLength, Length, /*isOptional=*/true);
 
+    // For backwards compatibility, the default is 1.
+    int64_t CancelOnSubsequentRequest = 1;
+    Req.getInt64(KeyCancelOnSubsequentRequest, CancelOnSubsequentRequest,
+                 /*isOptional=*/true);
+
     LangSupport &Lang = getGlobalContext().getSwiftLangSupport();
     return Lang.findLocalRenameRanges(
-        *PrimaryFilePath, Line, Column, Length, Args, CancellationToken,
+        *PrimaryFilePath, Line, Column, Length, Args, CancelOnSubsequentRequest,
+        CancellationToken,
         [Rec](const CancellableResult<std::vector<CategorizedRenameRanges>>
                   &Result) {
           Rec(createCategorizedRenameRangesResponse(Result));
@@ -2208,6 +2271,7 @@ void handleRequestImpl(sourcekitd_object_t ReqObj,
   HANDLE_REQUEST(RequestCodeCompleteUpdate, handleRequestCodeCompleteUpdate)
   HANDLE_REQUEST(RequestTypeContextInfo, handleRequestTypeContextInfo)
   HANDLE_REQUEST(RequestConformingMethodList, handleRequestConformingMethodList)
+  HANDLE_REQUEST(RequestSignatureHelp, handleRequestSignatureHelp)
 
   HANDLE_REQUEST(RequestIndex, handleRequestIndex)
   HANDLE_REQUEST(RequestIndexToStore, handleRequestIndexToStore)
@@ -3564,6 +3628,86 @@ static sourcekitd_response_t conformingMethodList(
   }
 }
 
+//===----------------------------------------------------------------------===//
+// Signature Help
+//===----------------------------------------------------------------------===//
+
+static sourcekitd_response_t
+signatureHelp(StringRef PrimaryFilePath, int64_t Offset,
+              ArrayRef<const char *> Args, std::optional<VFSOptions> vfsOptions,
+              SourceKitCancellationToken CancellationToken) {
+  ResponseBuilder RespBuilder;
+
+  class Consumer : public SignatureHelpConsumer {
+    ResponseBuilder::Dictionary SKResult;
+    std::optional<std::string> ErrorDescription;
+    bool WasCancelled = false;
+
+  public:
+    Consumer(ResponseBuilder Builder) : SKResult(Builder.getDictionary()) {}
+
+    void
+    handleResult(const swift::ide::FormattedSignatureHelp &Result) override {
+      SKResult.set(KeyActiveSignature, Result.ActiveSignature);
+
+      auto Signatures = SKResult.setArray(KeySignatures);
+
+      for (auto Signature : Result.Signatures) {
+        auto SignatureElem = Signatures.appendDictionary();
+
+        SignatureElem.set(KeyName, Signature.Text);
+
+        if (auto ActiveParam = Signature.ActiveParam)
+          SignatureElem.set(KeyActiveParameter, ActiveParam.value());
+
+        if (!Signature.DocComment.empty())
+          SignatureElem.set(KeyDocComment, Signature.DocComment);
+
+        auto Params = SignatureElem.setArray(KeyParameters);
+
+        for (auto Param : Signature.Params) {
+          auto ParamElem = Params.appendDictionary();
+
+          if (!Param.Name.empty())
+            ParamElem.set(KeyName, Param.Name);
+
+          ParamElem.set(KeyNameOffset, Param.Offset);
+          ParamElem.set(KeyNameLength, Param.Length);
+        }
+      }
+    }
+
+    void setReusingASTContext(bool flag) override {
+      if (flag)
+        SKResult.setBool(KeyReusingASTContext, flag);
+    }
+
+    void failed(StringRef ErrDescription) override {
+      ErrorDescription = ErrDescription.str();
+    }
+
+    void cancelled() override { WasCancelled = true; }
+
+    bool wasCancelled() const { return WasCancelled; }
+    bool isError() const { return ErrorDescription.has_value(); }
+    const char *getErrorDescription() const {
+      return ErrorDescription->c_str();
+    }
+  } Consumer(RespBuilder);
+
+  LangSupport &Lang = getGlobalContext().getSwiftLangSupport();
+  Lang.getSignatureHelp(PrimaryFilePath, Offset, Args, CancellationToken,
+                        Consumer, std::move(vfsOptions));
+
+  if (Consumer.wasCancelled()) {
+    return createErrorRequestCancelled();
+  }
+  if (Consumer.isError()) {
+    return createErrorRequestFailed(Consumer.getErrorDescription());
+  }
+  return RespBuilder.createResponse();
+}
+
 //===----------------------------------------------------------------------===//
 // Editor
 //===----------------------------------------------------------------------===//
@@ -3686,6 +3830,7 @@ static sourcekitd_response_t editorOpenInterface(
 static void
 editorOpenSwiftSourceInterface(StringRef Name, StringRef HeaderName,
                                ArrayRef<const char *> Args,
+                               bool CancelOnSubsequentRequest,
                                SourceKitCancellationToken CancellationToken,
                                ResponseReceiver Rec, bool EnableDeclarations) {
   SKEditorConsumerOptions Opts;
@@ -3694,8 +3839,9 @@ editorOpenSwiftSourceInterface(StringRef Name, StringRef HeaderName,
   Opts.EnableDeclarations = EnableDeclarations;
   auto EditC = std::make_shared<SKEditorConsumer>(Rec, Opts);
   LangSupport &Lang = getGlobalContext().getSwiftLangSupport();
-  Lang.editorOpenSwiftSourceInterface(Name, HeaderName, Args, CancellationToken,
-                                      EditC);
+  Lang.editorOpenSwiftSourceInterface(Name, HeaderName, Args,
+                                      CancelOnSubsequentRequest,
+                                      CancellationToken, EditC);
 }
 
 static void
@@ -4027,6 +4173,7 @@ fillDictionaryForDiagnosticInfo(ResponseBuilder::Dictionary Elem,
   UIdent SeverityUID;
   static UIdent UIDKindDiagWarning(KindDiagWarning.str());
   static UIdent UIDKindDiagError(KindDiagError.str());
+  static UIdent UIDKindDiagRemark(KindDiagRemark.str());
   switch (Info.Severity) {
   case DiagnosticSeverityKind::Warning:
     SeverityUID = UIDKindDiagWarning;
@@ -4034,6 +4181,9 @@ fillDictionaryForDiagnosticInfo(ResponseBuilder::Dictionary Elem,
   case DiagnosticSeverityKind::Error:
     SeverityUID = UIDKindDiagError;
     break;
+  case DiagnosticSeverityKind::Remark:
+    SeverityUID = UIDKindDiagRemark;
+    break;
   }
 
   Elem.set(KeySeverity, SeverityUID);
diff --git a/tools/lldb-moduleimport-test/CMakeLists.txt b/tools/lldb-moduleimport-test/CMakeLists.txt
index 66f4518c45558..72c9255aaa8a7 100644
--- a/tools/lldb-moduleimport-test/CMakeLists.txt
+++ b/tools/lldb-moduleimport-test/CMakeLists.txt
@@ -1,11 +1,13 @@
 add_swift_host_tool(lldb-moduleimport-test
   lldb-moduleimport-test.cpp
   SWIFT_COMPONENT testsuite-tools
+  HAS_SWIFT_MODULES
 )
 target_link_libraries(lldb-moduleimport-test
                       PRIVATE
                         swiftAST
                         swiftASTSectionImporter
                         swiftClangImporter
-                        swiftFrontend)
+                        swiftFrontend
+                        swiftCompilerModules)
 
diff --git a/tools/lldb-moduleimport-test/lldb-moduleimport-test.cpp b/tools/lldb-moduleimport-test/lldb-moduleimport-test.cpp
index cb569e61bef01..b6d368ee97c81 100644
--- a/tools/lldb-moduleimport-test/lldb-moduleimport-test.cpp
+++ b/tools/lldb-moduleimport-test/lldb-moduleimport-test.cpp
@@ -21,6 +21,7 @@
 #include "swift/AST/PrintOptions.h"
 #include "swift/ASTSectionImporter/ASTSectionImporter.h"
 #include "swift/Basic/LLVMInitialize.h"
+#include "swift/Basic/InitializeSwiftModules.h"
 #include "swift/Frontend/Frontend.h"
 #include "swift/Serialization/SerializedModuleLoader.h"
 #include "swift/Serialization/Validation.h"
@@ -45,12 +46,12 @@ void anchorForGetMainExecutable() {}
 using namespace llvm::MachO;
 
 static bool validateModule(
-    llvm::StringRef data, bool Verbose, bool requiresOSSAModules,
+    llvm::StringRef data, bool Verbose,
     swift::serialization::ValidationInfo &info,
     swift::serialization::ExtendedValidationInfo &extendedInfo,
     llvm::SmallVectorImpl<swift::serialization::SearchPath> &searchPaths) {
   info = swift::serialization::validateSerializedAST(
-      data, requiresOSSAModules,
+      data,
       /*requiredSDK*/ StringRef(), &extendedInfo, /* dependencies*/ nullptr,
       &searchPaths);
   if (info.status != swift::serialization::Status::Valid) {
@@ -239,6 +240,7 @@ collectASTModules(llvm::cl::list<std::string> &InputNames,
 int main(int argc, char **argv) {
   PROGRAM_START(argc, argv);
   INITIALIZE_LLVM();
+  initializeSwiftModules();
 
   // Command line handling.
   using namespace llvm::cl;
@@ -282,9 +284,6 @@ int main(int argc, char **argv) {
   opt<bool> QualifyTypes("qualify-types", desc("Qualify dumped types"),
                          cat(Visible));
 
-  opt<bool> EnableOSSAModules("enable-ossa-modules", init(false),
-                              desc("Serialize modules in OSSA"), cat(Visible));
-
   ParseCommandLineOptions(argc, argv);
 
   // Unregister our options so they don't interfere with the command line
@@ -329,7 +328,6 @@ int main(int argc, char **argv) {
     info = {};
     extendedInfo = {};
     if (!validateModule(StringRef(Module.first, Module.second), Verbose,
-                        EnableOSSAModules,
                         info, extendedInfo, searchPaths)) {
       llvm::errs() << "Malformed module!\n";
       return 1;
@@ -353,7 +351,6 @@ int main(int argc, char **argv) {
   Invocation.setModuleName("lldbtest");
   Invocation.getClangImporterOptions().ModuleCachePath = ModuleCachePath;
   Invocation.getLangOptions().EnableMemoryBufferImporter = true;
-  Invocation.getSILOptions().EnableOSSAModules = EnableOSSAModules;
 
   if (!ResourceDir.empty()) {
     Invocation.setRuntimeResourcePath(ResourceDir);
diff --git a/tools/swift-ast-script/ASTScript.h b/tools/swift-ast-script/ASTScript.h
deleted file mode 100644
index 5c0a10c0a7ce9..0000000000000
--- a/tools/swift-ast-script/ASTScript.h
+++ /dev/null
@@ -1,40 +0,0 @@
-//===--- ASTScript.h - AST script type --------------------------*- C++ -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-//
-// The AST for a swift-ast-script script.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef SWIFT_SCRIPTING_ASTSCRIPT_H
-#define SWIFT_SCRIPTING_ASTSCRIPT_H
-
-#include "swift/Basic/LLVM.h"
-
-namespace swift {
-namespace scripting {
-class ASTScriptConfiguration;
-
-class ASTScript {
-  ASTScriptConfiguration &Config;
-
-public:
-  ASTScript(ASTScriptConfiguration &config) : Config(config) {}
-
-  static std::unique_ptr<ASTScript> parse(ASTScriptConfiguration &config);
-
-  bool execute() const;
-};
-
-}
-}
-
-#endif
diff --git a/tools/swift-ast-script/ASTScriptConfiguration.cpp b/tools/swift-ast-script/ASTScriptConfiguration.cpp
deleted file mode 100644
index 033798696ce83..0000000000000
--- a/tools/swift-ast-script/ASTScriptConfiguration.cpp
+++ /dev/null
@@ -1,95 +0,0 @@
-//===--- ASTScriptConfiguration.cpp ---------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// Configuration parsing for an AST script.
-///
-//===----------------------------------------------------------------------===//
-
-#include "ASTScriptConfiguration.h"
-
-#include "swift/Basic/QuotedString.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/Support/raw_ostream.h"
-
-using namespace swift;
-using namespace scripting;
-
-std::unique_ptr<ASTScriptConfiguration>
-ASTScriptConfiguration::parse(CompilerInstance &compiler,
-                              ArrayRef<const char *> args) {
-  bool hadError = false;
-
-  std::unique_ptr<ASTScriptConfiguration> result(
-    new ASTScriptConfiguration(compiler));
-
-#define emitError(WHAT) do {                                                  \
-    llvm::errs() << "error: " << WHAT << "\n";                                \
-    hadError = true;                                                          \
-  } while (0)
-
-  auto popArg = [&](const char *what) -> StringRef {
-    // Gracefully handle the case of running out of arguments.
-    if (args.empty()) {
-      assert(what && "expected explanation here!");
-      emitError(what);
-      return "";
-    }
-
-    auto arg = args.front();
-    args = args.slice(1);
-    return arg;
-  };
-
-  auto setScriptFile = [&](StringRef filename) {
-    if (!result->ScriptFile.empty()) {
-      emitError("multiple script files ("
-                  << QuotedString(result->ScriptFile)
-                  << ", "
-                  << QuotedString(filename)
-                  << ")");
-    }
-    result->ScriptFile = filename;
-  };
-
-  // Parse the arguments.
-  while (!hadError && !args.empty()) {
-    StringRef arg = popArg(nullptr);
-    if (!arg.starts_with("-")) {
-      setScriptFile(arg);
-    } else if (arg == "-f") {
-      StringRef filename = popArg("expected path after -f");
-      if (!hadError)
-        setScriptFile(filename);
-    } else if (arg == "-h" || arg == "--help") {
-      llvm::errs()
-        << "usage: swift-ast-script <script-args> -- <compiler-args\n"
-           "accepted script arguments:\n"
-           "  <filename>\n"
-           "  -f <filename>\n"
-           "    Specify the file to use as the script; required argument\n";
-      hadError = true;
-    } else {
-      emitError("unknown argument " << QuotedString(arg));
-    }
-  }
-
-  // Check well-formedness.
-  if (!hadError) {
-    if (result->ScriptFile.empty()) {
-      emitError("script file is required");
-    }
-  }
-
-  if (hadError)
-    result.reset();
-  return result;
-}
diff --git a/tools/swift-ast-script/ASTScriptConfiguration.h b/tools/swift-ast-script/ASTScriptConfiguration.h
deleted file mode 100644
index 660f47906add4..0000000000000
--- a/tools/swift-ast-script/ASTScriptConfiguration.h
+++ /dev/null
@@ -1,45 +0,0 @@
-//===--- ASTScriptConfiguration.h - AST script configuration ----*- C++ -*-===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-//
-// Types for configuring an AST script invocation.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef SWIFT_SCRIPTING_ASTSCRIPTCONFIGURATION_H
-#define SWIFT_SCRIPTING_ASTSCRIPTCONFIGURATION_H
-
-#include "swift/Basic/LLVM.h"
-#include "llvm/ADT/StringRef.h"
-
-namespace swift {
-class CompilerInstance;
-
-namespace scripting {
-
-/// A configuration for working with an ASTScript.
-class ASTScriptConfiguration {
-  ASTScriptConfiguration(CompilerInstance &compiler) : Compiler(compiler) {}
-public:
-  CompilerInstance &Compiler;
-  StringRef ScriptFile;
-
-  /// Attempt to parse this configuration.
-  ///
-  /// Returns null if there's a problem.
-  static std::unique_ptr<ASTScriptConfiguration>
-  parse(CompilerInstance &compiler, ArrayRef<const char *> args);
-};
-
-}
-}
-
-#endif
diff --git a/tools/swift-ast-script/ASTScriptEvaluator.cpp b/tools/swift-ast-script/ASTScriptEvaluator.cpp
deleted file mode 100644
index 5229259d3e68c..0000000000000
--- a/tools/swift-ast-script/ASTScriptEvaluator.cpp
+++ /dev/null
@@ -1,148 +0,0 @@
-//===--- ASTScriptEvaluator.cpp -------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// AST script evaluation.
-///
-//===----------------------------------------------------------------------===//
-
-#include "ASTScript.h"
-#include "ASTScriptConfiguration.h"
-
-#include "swift/AST/ASTMangler.h"
-#include "swift/AST/ASTWalker.h"
-#include "swift/AST/Decl.h"
-#include "swift/AST/NameLookup.h"
-#include "swift/AST/NameLookupRequests.h"
-#include "swift/Frontend/Frontend.h"
-
-using namespace swift;
-using namespace scripting;
-
-namespace {
-
-class ASTScriptWalker : public ASTWalker {
-  const ASTScript &Script;
-  ProtocolDecl *ViewProtocol;
-
-public:
-  ASTScriptWalker(const ASTScript &script, ProtocolDecl *viewProtocol)
-    : Script(script), ViewProtocol(viewProtocol) {}
-
-  MacroWalking getMacroWalkingBehavior() const override {
-    return MacroWalking::Expansion;
-  }
-
-  PreWalkAction walkToDeclPre(Decl *D) override {
-    visit(D);
-    return Action::Continue();
-  }
-
-  void visit(const Decl *D) {
-    auto fn = dyn_cast<AbstractFunctionDecl>(D);
-    if (!fn) return;
-
-    // Suppress warnings.
-    (void) Script;
-
-    for (auto param : *fn->getParameters()) {
-      // The parameter must have function type.
-      auto paramType = param->getInterfaceType();
-      auto paramFnType = paramType->getAs<FunctionType>();
-      if (!paramFnType) continue;
-
-      // The parameter function must return a type parameter that
-      // conforms to SwiftUI.View.
-      auto paramResultType = paramFnType->getResult();
-      if (!paramResultType->isTypeParameter()) continue;
-      auto sig = fn->getGenericSignature();
-      if (!sig->requiresProtocol(paramResultType, ViewProtocol)) continue;
-
-      // The parameter must not be a @ViewBuilder parameter.
-      if (param->getResultBuilderType()) continue;
-
-      // Print the function.
-      printDecl(fn);
-    }
-  }
-
-  void printDecl(const ValueDecl *decl) {
-    // FIXME: there's got to be some better way to print an exact reference
-    // to a declaration, including its context.
-    printDecl(llvm::outs(), decl);
-    llvm::outs() << "\n";
-  }
-
-  void printDecl(llvm::raw_ostream &out, const ValueDecl *decl) {
-    if (auto accessor = dyn_cast<AccessorDecl>(decl)) {
-      printDecl(out, accessor->getStorage());
-      out << ".(accessor)";
-    } else {
-      printDeclContext(out, decl->getDeclContext());
-      out << decl->getName();
-    }
-  }
-
-  void printDeclContext(llvm::raw_ostream &out, const DeclContext *dc) {
-    if (!dc) return;
-    if (auto module = dyn_cast<ModuleDecl>(dc)) {
-      out << module->getName() << ".";
-    } else if (auto extension = dyn_cast<ExtensionDecl>(dc)) {
-      auto *extended = extension->getExtendedNominal();
-      if (extended) {
-        printDecl(out, extended);
-        out << ".";
-      }
-    } else if (auto decl = dyn_cast_or_null<ValueDecl>(dc->getAsDecl())) {
-      printDecl(out, decl);
-      out << ".";
-    } else {
-      printDeclContext(out, dc->getParent());
-    }
-  }
-};
-
-}
-
-bool ASTScript::execute() const {
-  // Hardcode the actual query we want to execute here.
-
-  auto &ctx = Config.Compiler.getASTContext();
-  auto swiftUI = ctx.getLoadedModule(ctx.getIdentifier("SwiftUI"));
-  if (!swiftUI) {
-    llvm::errs() << "error: SwiftUI module not loaded\n";
-    return true;
-  }
-
-  auto descriptor =
-      UnqualifiedLookupDescriptor(DeclNameRef(ctx.getIdentifier("View")),
-                                  swiftUI);
-  auto viewLookup = evaluateOrDefault(ctx.evaluator,
-                                      UnqualifiedLookupRequest{descriptor}, {});
-  auto viewProtocol =
-    dyn_cast_or_null<ProtocolDecl>(viewLookup.getSingleTypeResult());
-  if (!viewProtocol) {
-    llvm::errs() << "error: couldn't find SwiftUI.View protocol\n";
-    return true;
-  }
-
-  SmallVector<Decl*, 128> topLevelDecls;
-  swiftUI->getTopLevelDecls(topLevelDecls);
-
-  llvm::errs() << "found " << topLevelDecls.size() << " top-level declarations\n";
-
-  ASTScriptWalker walker(*this, viewProtocol);
-  for (auto decl : topLevelDecls) {
-    decl->walk(walker);
-  }
-
-  return false;
-}
diff --git a/tools/swift-ast-script/ASTScriptParser.cpp b/tools/swift-ast-script/ASTScriptParser.cpp
deleted file mode 100644
index 83092c9db3e34..0000000000000
--- a/tools/swift-ast-script/ASTScriptParser.cpp
+++ /dev/null
@@ -1,119 +0,0 @@
-//===--- ASTScriptParser.cpp ----------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// AST script parsing.
-///
-//===----------------------------------------------------------------------===//
-
-#include "swift/Basic/QuotedString.h"
-#include "swift/Frontend/Frontend.h"
-#include "swift/Parse/Lexer.h"
-#include "swift/Parse/Token.h"
-#include "llvm/Support/MemoryBuffer.h"
-
-#include "ASTScript.h"
-#include "ASTScriptConfiguration.h"
-
-using namespace swift;
-using namespace scripting;
-
-namespace {
-
-class ASTScriptParser {
-  ASTScriptConfiguration &Config;
-  ASTContext &Context;
-  DiagnosticEngine &Diags;
-  std::unique_ptr<llvm::MemoryBuffer> Buffer;
-  std::optional<Lexer> TheLexer;
-  Token Tok;
-
-public:
-  ASTScriptParser(ASTScriptConfiguration &config)
-    : Config(config), Context(config.Compiler.getASTContext()),
-      Diags(config.Compiler.getDiags()) {
-
-    auto &compiler = config.Compiler;
-
-    // Open the file and give it to the source manager.
-    auto bufferOrErr = llvm::MemoryBuffer::getFile(config.ScriptFile);
-    if (!bufferOrErr) {
-      llvm::errs() << "error opening file " << QuotedString(config.ScriptFile)
-                   << ": " << bufferOrErr.getError().message() << "\n";
-      return;
-    }
-    auto &sourceManager = compiler.getSourceMgr();
-    auto bufferID = sourceManager.addNewSourceBuffer(std::move(*bufferOrErr));
-
-    // Build and prime the lexer.
-    TheLexer.emplace(Context.LangOpts, sourceManager, bufferID,
-                     &Diags, LexerMode::Swift);
-    TheLexer->lex(Tok);
-  }
-
-  std::unique_ptr<ASTScript> parseFile() {
-    if (!TheLexer) return nullptr;
-    return parseTopLevel();
-  }
-
-private:
-  /***************************************************************************/
-  /*** Parsing primitives ****************************************************/
-  /***************************************************************************/
-
-  void consume(tok kind) {
-    assert(Tok.is(kind));
-    TheLexer->lex(Tok);
-  }
-
-  bool consumeIf(tok kind) {
-    if (Tok.isNot(kind)) return false;
-    consume(kind);
-    return true;
-  }
-
-  bool consumeIfExactly(StringRef literal) {
-    if (Tok.isNot(tok::identifier) || Tok.getText() != literal)
-      return false;
-    consume(tok::identifier);
-    return true;
-  }
-
-  bool consumeIfIdentifier(StringRef &ident) {
-    if (Tok.isNot(tok::identifier)) return false;
-    ident = Tok.getText();
-    consume(tok::identifier);
-    return true;
-  }
-
-  std::optional<StringRef> consumeIfIdentifier() {
-    StringRef ident;
-    return consumeIfIdentifier(ident) ? std::optional<StringRef>(ident)
-                                      : std::nullopt;
-  }
-
-  /***************************************************************************/
-  /*** ASTScript parsing *****************************************************/
-  /***************************************************************************/
-
-  std::unique_ptr<ASTScript> parseTopLevel();
-};
-
-} // end anonymous namespace
-
-/// ast-script ::= ???
-std::unique_ptr<ASTScript> ASTScriptParser::parseTopLevel() {
-  return std::unique_ptr<ASTScript>(new ASTScript(Config));
-}
-
-std::unique_ptr<ASTScript> ASTScript::parse(ASTScriptConfiguration &config) {
-  return ASTScriptParser(config).parseFile();
-}
diff --git a/tools/swift-ast-script/CMakeLists.txt b/tools/swift-ast-script/CMakeLists.txt
deleted file mode 100644
index 0b68c96baaf3e..0000000000000
--- a/tools/swift-ast-script/CMakeLists.txt
+++ /dev/null
@@ -1,12 +0,0 @@
-add_swift_host_tool(swift-ast-script
-  ASTScriptConfiguration.cpp
-  ASTScriptParser.cpp
-  ASTScriptEvaluator.cpp
-  swift-ast-script.cpp
-  SWIFT_COMPONENT tools
-  THINLTO_LD64_ADD_FLTO_CODEGEN_ONLY
-)
-target_link_libraries(swift-ast-script
-                      PRIVATE
-                        swiftAST
-                        swiftFrontendTool)
diff --git a/tools/swift-ast-script/swift-ast-script.cpp b/tools/swift-ast-script/swift-ast-script.cpp
deleted file mode 100644
index 2fd133bffd6c6..0000000000000
--- a/tools/swift-ast-script/swift-ast-script.cpp
+++ /dev/null
@@ -1,98 +0,0 @@
-//===--- swift-ast-script.cpp ---------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-///
-/// This utility is a command line tool that searches Swift code for
-/// declarations matching the given requirements.
-///
-//===----------------------------------------------------------------------===//
-
-#include "swift/Frontend/Frontend.h"
-#include "swift/FrontendTool/FrontendTool.h"
-#include "swift/Basic/LLVMInitialize.h"
-#include "ASTScript.h"
-#include "ASTScriptConfiguration.h"
-
-using namespace swift;
-using namespace scripting;
-
-namespace {
-
-class Observer : public FrontendObserver {
-  ArrayRef<const char *> Args;
-  std::unique_ptr<ASTScriptConfiguration> Config;
-  std::unique_ptr<ASTScript> Script;
-  bool HadError = false;
-
-public:
-  Observer(ArrayRef<const char *> args) : Args(args) {}
-
-  void configuredCompiler(CompilerInstance &instance) override {
-    Config = ASTScriptConfiguration::parse(instance, Args);
-    if (!Config) return flagError();
-
-    Script = ASTScript::parse(*Config);
-    if (!Script) return flagError();
-  }
-
-  void performedSemanticAnalysis(CompilerInstance &instance) override {
-    if (Script) {
-      if (Script->execute())
-        return flagError();
-    }
-  }
-
-  bool hadError() const {
-    return HadError;
-  }
-
-private:
-  void flagError() {
-    HadError = true;
-  }
-};
-
-}
-
-// ISO C++ does not allow 'main' to be used by a program [-Wmain]
-int main2(int argc, const char *argv[]) {
-  PROGRAM_START(argc, argv);
-
-  // Look for the first "--" in the arguments.
-  auto argBegin = argv + 1;
-  auto argEnd = argv + argc;
-  auto dashDash = std::find(argBegin, argEnd, StringRef("--"));
-  if (dashDash == argEnd) {
-    llvm::errs() << "error: missing '--' in arguments to separate "
-                    "script configuration from compiler arguments\n"
-                    "usage:\n"
-                    "  swift-grep <script_file> -- <compiler flags>\n";
-    return 1;
-  }
-
-  Observer observer(llvm::ArrayRef(argBegin, dashDash));
-
-  // Set up the frontend arguments.
-  unsigned numFrontendArgs = argEnd - (dashDash + 1);
-  SmallVector<const char *, 8> frontendArgs;
-  frontendArgs.reserve(numFrontendArgs + 1);
-  frontendArgs.append(dashDash + 1, argEnd);
-  frontendArgs.push_back("-typecheck");
-
-  int frontendResult =
-    performFrontend(frontendArgs, argv[0], (void*) &main2, &observer);
-
-  return (observer.hadError() ? 1 : frontendResult);
-}
-
-int main(int argc, const char *argv[]) {
-  return main2(argc, argv);
-}
diff --git a/tools/swift-def-to-strings-converter/swift-def-to-strings-converter.cpp b/tools/swift-def-to-strings-converter/swift-def-to-strings-converter.cpp
index 5bb5bf7ebda07..84c5e4bf51cd7 100644
--- a/tools/swift-def-to-strings-converter/swift-def-to-strings-converter.cpp
+++ b/tools/swift-def-to-strings-converter/swift-def-to-strings-converter.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -14,8 +14,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "swift/Basic/LLVMInitialize.h"
 #include "swift/Basic/Compiler.h"
+#include "swift/Basic/LLVMInitialize.h"
 #include "swift/Localization/LocalizationFormat.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallString.h"
diff --git a/tools/swift-demangle-yamldump/swift-demangle-yamldump.cpp b/tools/swift-demangle-yamldump/swift-demangle-yamldump.cpp
index 68590616df193..79722e4227fdf 100644
--- a/tools/swift-demangle-yamldump/swift-demangle-yamldump.cpp
+++ b/tools/swift-demangle-yamldump/swift-demangle-yamldump.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -20,6 +20,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/Basic/LLVM.h"
+#include "swift/Basic/LLVMInitialize.h"
 #include "swift/Demangling/Demangle.h"
 #include "swift/Demangling/ManglingMacros.h"
 #include "llvm/ADT/StringRef.h"
@@ -191,6 +192,8 @@ int main(int argc, char **argv) {
   // if main()'s first function call is passing argv[0].
   std::rand();
 #endif
+  PROGRAM_START(argc, argv);
+
   llvm::cl::ParseCommandLineOptions(argc, argv);
 
   swift::Demangle::DemangleOptions options;
diff --git a/tools/swift-demangle/swift-demangle.cpp b/tools/swift-demangle/swift-demangle.cpp
index 4be5c514ebfd7..759d7cbdbbaa2 100644
--- a/tools/swift-demangle/swift-demangle.cpp
+++ b/tools/swift-demangle/swift-demangle.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -14,6 +14,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "swift/Basic/LLVMInitialize.h"
 #include "swift/Demangling/Demangle.h"
 #include "swift/Demangling/ManglingFlavor.h"
 #include "swift/Demangling/ManglingMacros.h"
@@ -407,6 +408,8 @@ int main(int argc, char **argv) {
   // if main()'s first function call is passing argv[0].
   std::rand();
 #endif
+  PROGRAM_START(argc, argv);
+
   llvm::cl::ParseCommandLineOptions(argc, argv);
 
   swift::Demangle::DemangleOptions options;
diff --git a/tools/swift-ide-test/swift-ide-test.cpp b/tools/swift-ide-test/swift-ide-test.cpp
index 109373e4357ab..1361ec48e8ea4 100644
--- a/tools/swift-ide-test/swift-ide-test.cpp
+++ b/tools/swift-ide-test/swift-ide-test.cpp
@@ -43,6 +43,8 @@
 #include "swift/IDE/IDERequests.h"
 #include "swift/IDE/ModuleInterfacePrinting.h"
 #include "swift/IDE/REPLCodeCompletion.h"
+#include "swift/IDE/SignatureHelp.h"
+#include "swift/IDE/SignatureHelpFormatter.h"
 #include "swift/IDE/SourceEntityWalker.h"
 #include "swift/IDE/SyntaxModel.h"
 #include "swift/IDE/TypeContextInfo.h"
@@ -53,7 +55,7 @@
 #include "swift/Markup/Markup.h"
 #include "swift/Parse/ParseVersion.h"
 #include "swift/Sema/IDETypeChecking.h"
-#include "clang/Rewrite/Core/RewriteBuffer.h"
+#include "llvm/ADT/RewriteBuffer.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/CommandLine.h"
@@ -117,6 +119,7 @@ enum class ActionType {
   Range,
   TypeContextInfo,
   ConformingMethodList,
+  SignatureHelp,
 };
 
 class NullDebuggerClient : public DebuggerClient {
@@ -251,7 +254,9 @@ Action(llvm::cl::desc("Mode:"), llvm::cl::init(ActionType::None),
                       "Print types for all expressions in the file"),
            clEnumValN(ActionType::ConformingMethodList,
 	                    "conforming-methods",
-                      "Perform conforming method analysis for expression")));
+                      "Perform conforming method analysis for expression"),
+           clEnumValN(ActionType::SignatureHelp, "signature-help",
+                      "Perform signature help")));
 
 static llvm::cl::opt<std::string>
 SourceFilename("source-filename", llvm::cl::desc("Name of the source file"),
@@ -448,6 +453,10 @@ RandomSeed("random-seed", llvm::cl::value_desc("seed"),
                     llvm::cl::cat(Category),
                     llvm::cl::init(0));
 
+static llvm::cl::opt<bool> SourceOrderCompletion(
+    "source-order-completion",
+    llvm::cl::desc("Perform batch completion in source order"),
+    llvm::cl::cat(Category));
 
 static llvm::cl::opt<std::string>
 CompletionOutputDir("completion-output-dir", llvm::cl::value_desc("path"),
@@ -506,6 +515,17 @@ CodeCompletionAnnotateResults("code-completion-annotate-results",
                               llvm::cl::cat(Category),
                               llvm::cl::init(false));
 
+static llvm::cl::opt<bool>
+CodeCompletionSortByName("code-completion-sort-by-name",
+                         llvm::cl::desc("Sort completion results by name"),
+                         llvm::cl::cat(Category), llvm::cl::init(false));
+
+static llvm::cl::opt<bool>
+CodeCompletionVerifyUSRToDecl("code-completion-verify-usr-to-decl",
+                              llvm::cl::desc("Verify USR to Decl reconstruction"),
+                              llvm::cl::cat(Category),
+                              llvm::cl::init(true));
+
 static llvm::cl::opt<std::string>
 DebugClientDiscriminator("debug-client-discriminator",
   llvm::cl::desc("A discriminator to prefer in lookups"),
@@ -570,6 +590,11 @@ PreferTypeRepr("prefer-type-repr",
                llvm::cl::cat(Category),
                llvm::cl::init(true));
 
+static llvm::cl::opt<bool> PrintForDebugging(
+    "debug-print",
+    llvm::cl::desc("Print using the debug representation for types"),
+    llvm::cl::cat(Category), llvm::cl::init(true));
+
 static llvm::cl::opt<bool>
 FullyQualifiedTypes("fully-qualified-types",
                     llvm::cl::desc("Print fully qualified types"),
@@ -760,6 +785,10 @@ static llvm::cl::opt<std::string>
 ModuleName("module-name", llvm::cl::desc("The module name of the given test."),
            llvm::cl::cat(Category), llvm::cl::init("swift_ide_test"));
 
+static llvm::cl::opt<std::string>
+PackageName("package-name", llvm::cl::desc("The package name of the given test."),
+            llvm::cl::cat(Category));
+
 static llvm::cl::opt<bool>
 NoEmptyLineBetweenMembers("no-empty-line-between-members",
                           llvm::cl::desc("Print no empty line between members."),
@@ -770,6 +799,21 @@ static llvm::cl::opt<bool> DebugConstraintSolver("debug-constraints",
     llvm::cl::desc("Enable verbose debugging from the constraint solver."),
     llvm::cl::cat(Category));
 
+static llvm::cl::opt<unsigned>
+SolverMemoryThreshold("solver-memory-threshold",
+    llvm::cl::desc("Set the memory threshold for constraint solving."),
+    llvm::cl::cat(Category), llvm::cl::init(0));
+
+static llvm::cl::opt<unsigned>
+SolverScopeThreshold("solver-scope-threshold",
+    llvm::cl::desc("Set the solver scope threshold for constraint solving."),
+    llvm::cl::cat(Category), llvm::cl::init(0));
+
+static llvm::cl::opt<unsigned>
+SolverTrailThreshold("solver-trail-threshold",
+    llvm::cl::desc("Set the solver trail threshold for constraint solving."),
+    llvm::cl::cat(Category), llvm::cl::init(0));
+
 static llvm::cl::opt<bool>
 IncludeLocals("include-locals", llvm::cl::desc("Index local symbols too."),
               llvm::cl::cat(Category), llvm::cl::init(false));
@@ -1152,14 +1196,15 @@ printResult(CancellableResult<ResultType> Result,
   }
 }
 
-static int printTypeContextInfo(
-    CancellableResult<TypeContextInfoResult> CancellableResult) {
+static int
+printTypeContextInfo(CancellableResult<TypeContextInfoResult> CancellableResult,
+                     const PrintOptions &PO) {
   return printResult<TypeContextInfoResult>(
-      CancellableResult, [](const TypeContextInfoResult &Result) {
+      CancellableResult, [&](const TypeContextInfoResult &Result) {
         llvm::outs() << "-----BEGIN TYPE CONTEXT INFO-----\n";
         for (auto resultItem : Result.Results) {
           llvm::outs() << "- TypeName: ";
-          resultItem.ExpectedTy.print(llvm::outs());
+          resultItem.ExpectedTy.print(llvm::outs(), PO);
           llvm::outs() << "\n";
 
           llvm::outs() << "  TypeUSR: ";
@@ -1190,11 +1235,10 @@ static int printTypeContextInfo(
       });
 }
 
-static int doTypeContextInfo(const CompilerInvocation &InitInvok,
-                             StringRef SourceFilename,
-                             StringRef SecondSourceFileName,
-                             StringRef CodeCompletionToken,
-                             bool CodeCompletionDiagnostics) {
+static int
+doTypeContextInfo(const CompilerInvocation &InitInvok, StringRef SourceFilename,
+                  StringRef SecondSourceFileName, StringRef CodeCompletionToken,
+                  bool CodeCompletionDiagnostics, const PrintOptions &PO) {
   return performWithCompletionLikeOperationParams(
       InitInvok, SourceFilename, SecondSourceFileName, CodeCompletionToken,
       CodeCompletionDiagnostics,
@@ -1207,16 +1251,17 @@ static int doTypeContextInfo(const CompilerInvocation &InitInvok,
             Params.CompletionBuffer, Params.Offset, Params.DiagC,
             /*CancellationFlag=*/nullptr,
             [&](CancellableResult<TypeContextInfoResult> Result) {
-              ExitCode = printTypeContextInfo(Result);
+              ExitCode = printTypeContextInfo(Result, PO);
             });
         return ExitCode;
       });
 }
 
 static int printConformingMethodList(
-    CancellableResult<ConformingMethodListResults> CancellableResult) {
+    CancellableResult<ConformingMethodListResults> CancellableResult,
+    const PrintOptions &PO) {
   return printResult<ConformingMethodListResults>(
-      CancellableResult, [](const ConformingMethodListResults &Results) {
+      CancellableResult, [&](const ConformingMethodListResults &Results) {
         auto Result = Results.Result;
         if (!Result) {
           return 0;
@@ -1224,7 +1269,7 @@ static int printConformingMethodList(
         llvm::outs() << "-----BEGIN CONFORMING METHOD LIST-----\n";
 
         llvm::outs() << "- TypeName: ";
-        Result->ExprType.print(llvm::outs());
+        Result->ExprType.print(llvm::outs(), PO);
         llvm::outs() << "\n";
 
         llvm::outs() << "- Members: ";
@@ -1241,7 +1286,7 @@ static int printConformingMethodList(
           llvm::outs() << "\n";
 
           llvm::outs() << "     TypeName: ";
-          resultTy.print(llvm::outs());
+          resultTy.print(llvm::outs(), PO);
           llvm::outs() << "\n";
 
           StringRef BriefDoc = VD->getSemanticBriefComment();
@@ -1257,12 +1302,11 @@ static int printConformingMethodList(
       });
 }
 
-static int
-doConformingMethodList(const CompilerInvocation &InitInvok,
-                       StringRef SourceFilename, StringRef SecondSourceFileName,
-                       StringRef CodeCompletionToken,
-                       bool CodeCompletionDiagnostics,
-                       const std::vector<std::string> expectedTypeNames) {
+static int doConformingMethodList(
+    const CompilerInvocation &InitInvok, StringRef SourceFilename,
+    StringRef SecondSourceFileName, StringRef CodeCompletionToken,
+    bool CodeCompletionDiagnostics,
+    const std::vector<std::string> expectedTypeNames, const PrintOptions &PO) {
   SmallVector<const char *, 4> typeNames;
   for (auto &name : expectedTypeNames)
     typeNames.push_back(name.c_str());
@@ -1279,7 +1323,7 @@ doConformingMethodList(const CompilerInvocation &InitInvok,
             Params.CompletionBuffer, Params.Offset, Params.DiagC, typeNames,
             /*CancellationFlag=*/nullptr,
             [&](CancellableResult<ConformingMethodListResults> Result) {
-              ExitCode = printConformingMethodList(Result);
+              ExitCode = printConformingMethodList(Result, PO);
             });
         return ExitCode;
       });
@@ -1288,7 +1332,14 @@ doConformingMethodList(const CompilerInvocation &InitInvok,
 static void printCodeCompletionResultsImpl(
     ArrayRef<CodeCompletionResult *> Results, llvm::raw_ostream &OS,
     bool IncludeKeywords, bool IncludeComments, bool IncludeSourceText,
-    bool PrintAnnotatedDescription, const ASTContext *Ctx) {
+    bool PrintAnnotatedDescription, bool SortByName, const ASTContext *Ctx) {
+  std::vector<CodeCompletionResult *> SortedResultsStorage;
+  if (SortByName) {
+    SortedResultsStorage =
+        CodeCompletionContext::sortCompletionResults(Results);
+    Results = SortedResultsStorage;
+  }
+
   unsigned NumResults = 0;
   for (auto Result : Results) {
     if (!IncludeKeywords &&
@@ -1326,9 +1377,28 @@ static void printCodeCompletionResultsImpl(
       OS.write_escaped(buf);
     }
 
-    StringRef comment = Result->getBriefDocComment();
-    if (IncludeComments && !comment.empty()) {
-      OS << "; comment=" << comment;
+    StringRef BriefComment = Result->getBriefDocComment();
+    if (IncludeComments) {
+      if (!BriefComment.empty()) {
+        OS << "; briefcomment=" << BriefComment;
+      }
+
+      {
+        SmallString<256> CommentAsXML;
+        llvm::raw_svector_ostream CommentOS(CommentAsXML);
+
+        if (Result->printFullDocCommentAsXML(CommentOS) &&
+            !CommentAsXML.empty())
+          OS << "; xmlcomment=" << CommentAsXML;
+      }
+
+      {
+        SmallString<256> RawComment;
+        llvm::raw_svector_ostream CommentOS(RawComment);
+
+        if (Result->printRawDocComment(CommentOS) && !RawComment.empty())
+          OS << "; rawcomment=" << RawComment;
+      }
     }
 
     if (Ctx) {
@@ -1338,7 +1408,7 @@ static void printCodeCompletionResultsImpl(
           Result->getDiagnosticSeverityAndMessage(Scratch, *Ctx);
       if (DiagSeverityAndMessage.first !=
           CodeCompletionDiagnosticSeverity::None) {
-        OS << "; diagnostics=" << comment;
+        OS << "; diagnostics=";
         switch (DiagSeverityAndMessage.first) {
         case CodeCompletionDiagnosticSeverity::Error:
           OS << "error";
@@ -1375,7 +1445,7 @@ printCodeCompletionLookedupTypeNames(ArrayRef<NullTerminatedStringRef> names,
   sortedNames.append(names.begin(), names.end());
   llvm::sort(sortedNames,
      [](NullTerminatedStringRef a, NullTerminatedStringRef b) {
-        return a.compare(b) <= 0;
+        return a.compare(b) < 0;
   });
 
   OS << "LookedupTypeNames: [";
@@ -1386,16 +1456,109 @@ printCodeCompletionLookedupTypeNames(ArrayRef<NullTerminatedStringRef> names,
   OS << "]\n";
 }
 
+static void printWithEscaping(StringRef Str, llvm::raw_ostream &OS) {
+  for (char C : Str) {
+    switch (C) {
+    case '\n':
+      OS << "\\n";
+      break;
+    case '\r':
+      OS << "\\r";
+      break;
+    case '\t':
+      OS << "\\t";
+      break;
+    case '\v':
+      OS << "\\v";
+      break;
+    case '\f':
+      OS << "\\f";
+      break;
+    default:
+      OS << C;
+      break;
+    }
+  }
+}
+
+static void printSignatureHelpResultsImpl(const FormattedSignatureHelp &Result,
+                                          llvm::raw_ostream &OS) {
+  OS << "Begin signatures, " << Result.Signatures.size() << " items\n";
+
+  for (unsigned i = 0; i < Result.Signatures.size(); ++i) {
+    const auto &Signature = Result.Signatures[i];
+    if (i == Result.ActiveSignature) {
+      OS << "Signature[Active]: ";
+    } else {
+      OS << "Signature: ";
+    }
+
+    StringRef signatureText = Signature.Text;
+
+    unsigned currentPos = 0;
+    for (unsigned j = 0; j < Signature.Params.size(); ++j) {
+      const auto &Param = Signature.Params[j];
+
+      if (Param.Offset > currentPos) {
+        OS << signatureText.substr(currentPos, Param.Offset - currentPos);
+      }
+
+      OS << "<param";
+      if (!Param.Name.empty()) {
+        OS << " name=\"" << Param.Name << '"';
+      }
+      if (Signature.ActiveParam && *Signature.ActiveParam == j) {
+        OS << " active";
+      }
+      OS << ">";
+      OS << signatureText.substr(Param.Offset, Param.Length);
+      OS << "</param>";
+
+      currentPos = Param.Offset + Param.Length;
+    }
+
+    if (currentPos < signatureText.size()) {
+      OS << signatureText.substr(currentPos);
+    }
+
+    if (!Signature.DocComment.empty()) {
+      OS << "; Documentation=";
+      printWithEscaping(Signature.DocComment, OS);
+    }
+
+    OS << "\n";
+  }
+
+  OS << "End signatures\n";
+}
+
+static int printSignatureHelpResults(
+    CancellableResult<SignatureHelpResults> CancellableResult) {
+  llvm::raw_fd_ostream &OS = llvm::outs();
+  return printResult<SignatureHelpResults>(
+      CancellableResult, [&](const SignatureHelpResults &Results) {
+        if (Results.Result) {
+          llvm::BumpPtrAllocator Allocator;
+          SignatureHelpFormatter Formatter(Allocator);
+          auto FormattedResult = Formatter.format(*Results.Result);
+          printSignatureHelpResultsImpl(FormattedResult, OS);
+        } else {
+          OS << "No signature help results\n";
+        }
+        return 0;
+      });
+}
+
 static int printCodeCompletionResults(
     CancellableResult<CodeCompleteResult> CancellableResult,
     bool IncludeKeywords, bool IncludeComments, bool IncludeSourceText,
-    bool PrintAnnotatedDescription) {
+    bool PrintAnnotatedDescription, bool SortByName) {
   llvm::raw_fd_ostream &OS = llvm::outs();
   return printResult<CodeCompleteResult>(
       CancellableResult, [&](const CodeCompleteResult &Result) {
         printCodeCompletionResultsImpl(
             Result.ResultSink.Results, OS, IncludeKeywords, IncludeComments,
-            IncludeSourceText, PrintAnnotatedDescription,
+            IncludeSourceText, PrintAnnotatedDescription, SortByName,
             &Result.Info.compilerInstance->getASTContext());
         printCodeCompletionLookedupTypeNames(
             Result.Info.completionContext->LookedupNominalTypeNames, OS);
@@ -1403,15 +1566,38 @@ static int printCodeCompletionResults(
       });
 }
 
+static int doSignatureHelp(const CompilerInvocation &InitInvok,
+                           StringRef SourceFilename,
+                           StringRef SecondSourceFileName,
+                           StringRef SignatureHelpToken,
+                           bool SignatureHelpDiagnostics) {
+  return performWithCompletionLikeOperationParams(
+      InitInvok, SourceFilename, SecondSourceFileName, SignatureHelpToken,
+      SignatureHelpDiagnostics,
+      [&](CompletionLikeOperationParams Params) -> bool {
+        IDEInspectionInstance Inst(std::make_shared<PluginRegistry>());
+        int ExitCode = 2;
+        Inst.signatureHelp(Params.Invocation, Params.Args, Params.FileSystem,
+                           Params.CompletionBuffer, Params.Offset, Params.DiagC,
+                           /*CancellationFlag=*/nullptr,
+                           [&](CancellableResult<SignatureHelpResults> Result) {
+                             ExitCode = printSignatureHelpResults(Result);
+                           });
+        return ExitCode;
+      });
+}
+
 static int
 doCodeCompletion(const CompilerInvocation &InitInvok, StringRef SourceFilename,
                  StringRef SecondSourceFileName, StringRef CodeCompletionToken,
                  bool CodeCompletionDiagnostics, bool CodeCompletionKeywords,
                  bool CodeCompletionComments,
                  bool CodeCompletionAnnotateResults,
+                 bool CodeCompletionSortByName,
                  bool CodeCompletionAddInitsToTopLevel,
                  bool CodeCompletionAddCallWithNoDefaultArgs,
-                 bool CodeCompletionSourceText) {
+                 bool CodeCompletionSourceText,
+                 bool CodeCompletionVerifyUSRToDecl) {
   std::unique_ptr<ide::OnDiskCodeCompletionCache> OnDiskCache;
   if (!options::CompletionCachePath.empty()) {
     OnDiskCache = std::make_unique<ide::OnDiskCodeCompletionCache>(
@@ -1423,6 +1609,7 @@ doCodeCompletion(const CompilerInvocation &InitInvok, StringRef SourceFilename,
   CompletionContext.setAddInitsToTopLevel(CodeCompletionAddInitsToTopLevel);
   CompletionContext.setAddCallWithNoDefaultArgs(
       CodeCompletionAddCallWithNoDefaultArgs);
+  CompletionContext.setVerifyUSRToDecl(CodeCompletionVerifyUSRToDecl);
 
   return performWithCompletionLikeOperationParams(
       InitInvok, SourceFilename, SecondSourceFileName, CodeCompletionToken,
@@ -1437,7 +1624,8 @@ doCodeCompletion(const CompilerInvocation &InitInvok, StringRef SourceFilename,
             [&](CancellableResult<CodeCompleteResult> Result) {
               ExitCode = printCodeCompletionResults(
                   Result, CodeCompletionKeywords, CodeCompletionComments,
-                  CodeCompletionSourceText, CodeCompletionAnnotateResults);
+                  CodeCompletionSourceText, CodeCompletionAnnotateResults,
+                  CodeCompletionSortByName);
             });
         return ExitCode;
       });
@@ -1450,9 +1638,11 @@ static int doBatchCodeCompletion(const CompilerInvocation &InitInvok,
                                  bool CodeCompletionKeywords,
                                  bool CodeCompletionComments,
                                  bool CodeCompletionAnnotateResults,
+                                 bool CodeCompletionSortByName,
                                  bool CodeCompletionAddInitsToTopLevel,
                                  bool CodeCompletionAddCallWithNoDefaultArgs,
-                                 bool CodeCompletionSourceText) {
+                                 bool CodeCompletionSourceText,
+                                 bool CodeCompletionVerifyUSRToDecl) {
   auto FileBufOrErr = llvm::MemoryBuffer::getFile(SourceFilename);
   if (!FileBufOrErr) {
     llvm::errs() << "error opening input file: "
@@ -1501,7 +1691,7 @@ static int doBatchCodeCompletion(const CompilerInvocation &InitInvok,
                    << TargetTokName << "\"\n";
       return 1;
     }
-  } else {
+  } else if (!options::SourceOrderCompletion) {
     // Shuffle tokens to detect order-dependent bugs.
     if (CCTokens.empty()) {
       llvm::errs()
@@ -1602,6 +1792,7 @@ static int doBatchCodeCompletion(const CompilerInvocation &InitInvok,
     CompletionContext.setAddInitsToTopLevel(CodeCompletionAddInitsToTopLevel);
     CompletionContext.setAddCallWithNoDefaultArgs(
         CodeCompletionAddCallWithNoDefaultArgs);
+    CompletionContext.setVerifyUSRToDecl(CodeCompletionVerifyUSRToDecl);
 
     PrintingDiagnosticConsumer PrintDiags;
     auto completionStart = std::chrono::high_resolution_clock::now();
@@ -1621,7 +1812,7 @@ static int doBatchCodeCompletion(const CompilerInvocation &InitInvok,
             printCodeCompletionResultsImpl(
                 Result->ResultSink.Results, OS, IncludeKeywords,
                 IncludeComments, IncludeSourceText,
-                CodeCompletionAnnotateResults,
+                CodeCompletionAnnotateResults, CodeCompletionSortByName,
                 &Result->Info.compilerInstance->getASTContext());
             printCodeCompletionLookedupTypeNames(
                 Result->Info.completionContext->LookedupNominalTypeNames, OS);
@@ -2082,7 +2273,7 @@ static int doDumpImporterLookupTables(const CompilerInvocation &InitInvok,
 class StructureAnnotator : public ide::SyntaxModelWalker {
   SourceManager &SM;
   unsigned BufferID;
-  clang::RewriteBuffer RewriteBuf;
+  llvm::RewriteBuffer RewriteBuf;
   std::vector<SyntaxStructureNode> NodeStack;
   CharSourceRange LastPoppedNodeRange;
 
@@ -2342,15 +2533,19 @@ class AnnotationPrinter : public SourceEntityWalker {
     return true;
   }
 
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type Ty,
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type Ty,
                           ReferenceMetaData Data) override {
-    if (!Data.isImplicit)
-      annotateSourceEntity({ Range, D, CtorTyRef, /*IsRef=*/true });
+    if (Data.isImplicit) {
+      return true;
+    }
+    CharSourceRange CharRange = Lexer::getCharSourceRangeFromSourceRange(
+        D->getASTContext().SourceMgr, Range);
+    annotateSourceEntity({CharRange, D, CtorTyRef, /*IsRef=*/true});
     return true;
   }
 
-  bool visitSubscriptReference(ValueDecl *D, CharSourceRange Range,
+  bool visitSubscriptReference(ValueDecl *D, SourceRange Range,
                                ReferenceMetaData Data,
                                bool IsOpenBracket) override {
     return visitDeclReference(D, Range, nullptr, nullptr, Type(), Data);
@@ -2683,7 +2878,8 @@ static int doPrintExpressionTypes(const CompilerInvocation &InitInvok,
 }
 
 static int doPrintLocalTypes(const CompilerInvocation &InitInvok,
-                             const std::vector<std::string> ModulesToPrint) {
+                             const std::vector<std::string> ModulesToPrint,
+                             const PrintOptions &PO) {
   using NodeKind = Demangle::Node::Kind;
 
   CompilerInvocation Invocation(InitInvok);
@@ -2704,8 +2900,6 @@ static int doPrintLocalTypes(const CompilerInvocation &InitInvok,
 
   int ExitCode = 0;
 
-  PrintOptions Options = PrintOptions::printDeclarations();
-
   for (StringRef ModuleName : ModulesToPrint) {
     auto *M = getModuleByFullName(Context, ModuleName);
     if (!M) {
@@ -2796,9 +2990,7 @@ static int doPrintLocalTypes(const CompilerInvocation &InitInvok,
 
       llvm::outs() << remangled << "\n";
 
-      auto Options = PrintOptions::printDeclarations();
-      Options.PrintAccess = false;
-      LTD->print(llvm::outs(), Options);
+      LTD->print(llvm::outs(), PO);
       llvm::outs() << "\n";
     }
   }
@@ -3339,8 +3531,7 @@ class ASTTypePrinter : public ASTWalker {
 } // unnamed namespace
 
 static int doPrintTypes(const CompilerInvocation &InitInvok,
-                        StringRef SourceFilename,
-                        bool FullyQualifiedTypes) {
+                        StringRef SourceFilename, const PrintOptions &PO) {
   CompilerInvocation Invocation(InitInvok);
   Invocation.getFrontendOptions().InputsAndOutputs.addInputFile(SourceFilename);
 
@@ -3356,9 +3547,7 @@ static int doPrintTypes(const CompilerInvocation &InitInvok,
   registerIDERequestFunctions(CI.getASTContext().evaluator);
   CI.performSema();
 
-  PrintOptions Options = PrintOptions::printDeclarations();
-  Options.FullyQualifiedTypes = FullyQualifiedTypes;
-  ASTTypePrinter Printer(CI.getSourceMgr(), Options);
+  ASTTypePrinter Printer(CI.getSourceMgr(), PO);
 
   CI.getMainModule()->walk(Printer);
 
@@ -3399,19 +3588,6 @@ class ASTCommentPrinter : public ASTWalker {
   ASTCommentPrinter(SourceManager &SM, XMLValidator &TheXMLValidator)
       : OS(llvm::outs()), SM(SM), TheXMLValidator(TheXMLValidator) {}
 
-  void printWithEscaping(StringRef Str) {
-    for (char C : Str) {
-      switch (C) {
-      case '\n': OS << "\\n"; break;
-      case '\r': OS << "\\r"; break;
-      case '\t': OS << "\\t"; break;
-      case '\v': OS << "\\v"; break;
-      case '\f': OS << "\\f"; break;
-      default:   OS << C;     break;
-      }
-    }
-  }
-
   void printDeclName(const ValueDecl *VD) {
     if (auto *NTD = dyn_cast<NominalTypeDecl>(VD->getDeclContext())) {
       Identifier Id = NTD->getName();
@@ -3462,6 +3638,12 @@ class ASTCommentPrinter : public ASTWalker {
       case AccessorKind::Init:
         OS << "init accessor for ";
         break;
+      case AccessorKind::Borrow:
+        OS << "borrow accessor for ";
+        break;
+      case AccessorKind::Mutate:
+        OS << "mutate accessor for ";
+        break;
       }
       printDeclName(storage);
       OS << ">";
@@ -3478,7 +3660,7 @@ class ASTCommentPrinter : public ASTWalker {
     }
     OS << "[";
     for (auto &SRC : RC.Comments)
-      printWithEscaping(SRC.RawText);
+      printWithEscaping(SRC.RawText, OS);
     OS << "]";
   }
 
@@ -3489,7 +3671,7 @@ class ASTCommentPrinter : public ASTWalker {
       return;
     }
     OS << "[";
-    printWithEscaping(Brief);
+    printWithEscaping(Brief, OS);
     OS << "]";
   }
 
@@ -3505,7 +3687,7 @@ class ASTCommentPrinter : public ASTWalker {
       return;
     }
     OS << "[";
-    printWithEscaping(XML);
+    printWithEscaping(XML, OS);
     OS << "]";
 
     auto Status = TheXMLValidator.validate(XML);
@@ -3722,9 +3904,14 @@ static int doPrintModuleImports(const CompilerInvocation &InitInvok,
       llvm::outs() << ":\n";
 
       scratch.clear();
-      next.importedModule->getImportedModules(
-          scratch, ModuleDecl::ImportFilterKind::Exported);
-      // FIXME: ImportFilterKind::ShadowedByCrossImportOverlay?
+      if (options::ModulePrintHidden) {
+        next.importedModule->getImportedModules(
+            scratch, ModuleDecl::getImportFilterAll());
+      } else {
+        next.importedModule->getImportedModules(
+            scratch, ModuleDecl::ImportFilterKind::Exported);
+        // FIXME: ImportFilterKind::ShadowedByCrossImportOverlay?
+      }
       for (auto &import : scratch) {
         llvm::outs() << "\t" << import.importedModule->getName();
         for (auto accessPathPiece : import.accessPath) {
@@ -3889,10 +4076,12 @@ class TypeReconstructWalker : public SourceEntityWalker {
   llvm::raw_ostream &Stream;
   llvm::DenseSet<ValueDecl *> SeenDecls;
   llvm::SmallVector<DeclContext *, 2> NestedDCs;
+  const PrintOptions &PO;
 
 public:
-  TypeReconstructWalker(ASTContext &Ctx, llvm::raw_ostream &Stream)
-      : Ctx(Ctx), Stream(Stream) {}
+  TypeReconstructWalker(ASTContext &Ctx, llvm::raw_ostream &Stream,
+                        const PrintOptions &PO)
+      : Ctx(Ctx), Stream(Stream), PO(PO) {}
 
   bool walkToDeclPre(Decl *D, CharSourceRange range) override {
     if (auto *VD = dyn_cast<ValueDecl>(D)) {
@@ -3909,11 +4098,13 @@ class TypeReconstructWalker : public SourceEntityWalker {
     return true;
   }
 
-  bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
-                          TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type T,
+  bool visitDeclReference(ValueDecl *D, SourceRange Range, TypeDecl *CtorTyRef,
+                          ExtensionDecl *ExtTyRef, Type T,
                           ReferenceMetaData Data) override {
+    CharSourceRange CharRange = Lexer::getCharSourceRangeFromSourceRange(
+        D->getASTContext().SourceMgr, Range);
     if (SeenDecls.insert(D).second)
-      tryDemangleDecl(D, Range, /*isRef=*/true);
+      tryDemangleDecl(D, CharRange, /*isRef=*/true);
 
     if (T) {
       T = T->getRValueType();
@@ -3921,7 +4112,7 @@ class TypeReconstructWalker : public SourceEntityWalker {
                       (NestedDCs.empty()
                        ? D->getDeclContext()
                        : NestedDCs.back()),
-                      Range);
+                      CharRange);
     }
     return true;
   }
@@ -3935,7 +4126,7 @@ class TypeReconstructWalker : public SourceEntityWalker {
         Demangle::getTypeForMangling(Ctx, mangledName));
     Stream << "type: ";
     if (ReconstructedType) {
-      ReconstructedType->print(Stream);
+      ReconstructedType->print(Stream, PO);
     } else {
       Stream << "FAILURE";
     }
@@ -3960,7 +4151,11 @@ class TypeReconstructWalker : public SourceEntityWalker {
     }
 
     if (TypeDecl *reDecl = Demangle::getTypeDeclForUSR(Ctx, USR)) {
-      PrintOptions POpts;
+      PrintOptions POpts = PO.clone();
+      POpts.TypeDefinitions = false;
+      POpts.VarInitializers = false;
+      POpts.FunctionDefinitions = false;
+      POpts.PrintExprs = false;
       POpts.PreferTypeRepr = false;
       POpts.PrintParameterSpecifiers = true;
       reDecl->print(Stream, POpts);
@@ -3972,7 +4167,7 @@ class TypeReconstructWalker : public SourceEntityWalker {
 };
 
 static int doReconstructType(const CompilerInvocation &InitInvok,
-                             StringRef SourceFilename) {
+                             StringRef SourceFilename, const PrintOptions &PO) {
   CompilerInvocation Invocation(InitInvok);
   Invocation.getFrontendOptions().InputsAndOutputs.addInputFile(SourceFilename);
   Invocation.getLangOptions().DisableAvailabilityChecking = false;
@@ -3996,15 +4191,14 @@ static int doReconstructType(const CompilerInvocation &InitInvok,
       break;
   }
   assert(SF && "no source file?");
-  TypeReconstructWalker Walker(SF->getASTContext(), llvm::outs());
+  TypeReconstructWalker Walker(SF->getASTContext(), llvm::outs(), PO);
   Walker.walk(SF);
   return 0;
 }
 
 static int doPrintRangeInfo(const CompilerInvocation &InitInvok,
-                            StringRef SourceFileName,
-                            StringRef StartPos,
-                            StringRef EndPos) {
+                            StringRef SourceFileName, StringRef StartPos,
+                            StringRef EndPos, const PrintOptions &PO) {
   auto StartOp = parseLineCol(StartPos);
   auto EndOp = parseLineCol(EndPos);
   if (!StartOp.has_value() || !EndOp.has_value())
@@ -4043,7 +4237,7 @@ static int doPrintRangeInfo(const CompilerInvocation &InitInvok,
                                          EndLineCol.second);
   ResolvedRangeInfo Result = evaluateOrDefault(SF->getASTContext().evaluator,
     RangeInfoRequest(RangeInfoOwner({SF, StartLoc, EndLoc})), ResolvedRangeInfo());
-  Result.print(llvm::outs());
+  Result.print(llvm::outs(), PO);
   return 0;
 }
 
@@ -4344,8 +4538,8 @@ int main(int argc, char *argv[]) {
         // We are leaking these results but it doesn't matter since the process
         // just terminates afterwards anyway.
         auto contextualResult = new CodeCompletionResult(
-            *contextFreeResult, SemanticContextKind::OtherModule,
-            CodeCompletionFlair(),
+            *contextFreeResult, /*DeclOrCtx=*/nullptr,
+            SemanticContextKind::OtherModule, CodeCompletionFlair(),
             /*numBytesToErase=*/0, CodeCompletionResultTypeRelation::Unrelated,
             ContextualNotRecommendedReason::None);
         contextualResults.push_back(contextualResult);
@@ -4354,6 +4548,7 @@ int main(int argc, char *argv[]) {
           contextualResults, llvm::outs(), options::CodeCompletionKeywords,
           options::CodeCompletionComments, options::CodeCompletionSourceText,
           options::CodeCompletionAnnotateResults,
+          options::CodeCompletionSortByName,
           /*Ctx=*/nullptr);
     }
 
@@ -4388,13 +4583,13 @@ int main(int argc, char *argv[]) {
     InitInvok.getFrontendOptions().InputsAndOutputs.addInputFile(File);
 
   for (const auto &featureArg : options::EnableExperimentalFeatures) {
-    if (auto feature = getExperimentalFeature(featureArg)) {
+    if (auto feature = Feature::getExperimentalFeature(featureArg)) {
       InitInvok.getLangOptions().enableFeature(*feature);
     }
   }
 
   for (const auto &featureArg : options::EnableUpcomingFeatures) {
-    if (auto feature = getUpcomingFeature(featureArg)) {
+    if (auto feature = Feature::getUpcomingFeature(featureArg)) {
       InitInvok.getLangOptions().enableFeature(*feature);
     }
   }
@@ -4404,6 +4599,10 @@ int main(int argc, char *argv[]) {
   InitInvok.setMainExecutablePath(mainExecutablePath);
   InitInvok.setModuleName(options::ModuleName);
 
+  if (!options::PackageName.empty()) {
+    InitInvok.getLangOptions().PackageName = options::PackageName;
+  }
+
   InitInvok.setSDKPath(options::SDK);
 
   for (auto macro : options::DefineAvailability) {
@@ -4493,8 +4692,8 @@ int main(int argc, char *argv[]) {
         options::ModuleCachePath[options::ModuleCachePath.size()-1];
   }
   if (!options::AccessNotesPath.empty()) {
-    InitInvok.getFrontendOptions().AccessNotesPath =
-        options::AccessNotesPath[options::AccessNotesPath.size()-1];
+    InitInvok.getLangOptions().AccessNotesPath =
+        options::AccessNotesPath[options::AccessNotesPath.size() - 1];
   }
   if (options::ParseAsLibrary) {
     InitInvok.getFrontendOptions().InputMode =
@@ -4546,12 +4745,19 @@ int main(int argc, char *argv[]) {
   }
   InitInvok.getLangOptions().EnableObjCAttrRequiresFoundation =
     !options::DisableObjCAttrRequiresFoundationModule;
-  for (auto prefix : options::DebugForbidTypecheckPrefix) {
-    InitInvok.getTypeCheckerOptions().DebugForbidTypecheckPrefixes.push_back(
-        prefix);
-  }
-  InitInvok.getTypeCheckerOptions().DebugConstraintSolver =
-      options::DebugConstraintSolver;
+
+  auto &TypeCheckOpts = InitInvok.getTypeCheckerOptions();
+  for (auto prefix : options::DebugForbidTypecheckPrefix)
+    TypeCheckOpts.DebugForbidTypecheckPrefixes.push_back(prefix);
+
+  TypeCheckOpts.DebugConstraintSolver = options::DebugConstraintSolver;
+
+  if (auto &memLimit = options::SolverMemoryThreshold)
+    TypeCheckOpts.SolverMemoryThreshold = memLimit;
+  if (auto &scopeLimit = options::SolverScopeThreshold)
+    TypeCheckOpts.SolverScopeThreshold = scopeLimit;
+  if (auto &trailLimit = options::SolverTrailThreshold)
+    TypeCheckOpts.SolverTrailThreshold = trailLimit;
 
   for (auto ConfigName : options::BuildConfigs)
     InitInvok.getLangOptions().addCustomConditionalCompilationFlag(ConfigName);
@@ -4582,6 +4788,8 @@ int main(int argc, char *argv[]) {
     InitInvok.computeCXXStdlibOptions();
   }
 
+  InitInvok.computeAArch64TBIOptions();
+
   if (!options::InProcessPluginServerPath.empty()) {
     InitInvok.getSearchPathOptions().InProcessPluginServerPath =
         options::InProcessPluginServerPath;
@@ -4630,41 +4838,44 @@ int main(int argc, char *argv[]) {
     }
   }
 
-  PrintOptions PrintOpts;
-  if (options::PrintInterface) {
-    PrintOpts = PrintOptions::printModuleInterface(
+  PrintOptions PrintOpts = [&] {
+    if (options::PrintInterface) {
+      return PrintOptions::printModuleInterface(
         InitInvok.getFrontendOptions().PrintFullConvention);
-  } else if (options::PrintInterfaceForDoc) {
-    PrintOpts = PrintOptions::printDocInterface();
-  } else {
-    PrintOpts = PrintOptions::printEverything();
-    PrintOpts.FullyQualifiedTypes = options::FullyQualifiedTypes;
-    PrintOpts.FullyQualifiedTypesIfAmbiguous =
-      options::FullyQualifiedTypesIfAmbiguous;
-    PrintOpts.SynthesizeSugarOnTypes = options::SynthesizeSugarOnTypes;
-    PrintOpts.AbstractAccessors = options::AbstractAccessors;
-    PrintOpts.FunctionDefinitions = options::FunctionDefinitions;
-    PrintOpts.PrintExprs = options::Expressions;
-    PrintOpts.PreferTypeRepr = options::PreferTypeRepr;
-    PrintOpts.ExplodePatternBindingDecls = options::ExplodePatternBindingDecls;
-    PrintOpts.PrintImplicitAttrs = options::PrintImplicitAttrs;
-    PrintOpts.PrintAccess = options::PrintAccess;
-    PrintOpts.AccessFilter = options::AccessFilter;
-    PrintOpts.PrintDocumentationComments = !options::SkipDocumentationComments;
-    PrintOpts.SkipPrivateSystemDecls = options::SkipPrivateSystemDecls;
-    PrintOpts.SkipUnsafeCXXMethods = options::SkipUnsafeCXXMethods;
-    PrintOpts.SkipUnavailable = options::SkipUnavailable;
-    PrintOpts.SkipDeinit = options::SkipDeinit;
-    PrintOpts.SkipImports = options::SkipImports;
-    PrintOpts.SkipOverrides = options::SkipOverrides;
-    if (options::SkipParameterNames) {
-      PrintOpts.ArgAndParamPrinting
-        = PrintOptions::ArgAndParamPrintingMode::ArgumentOnly;
-    } else if (options::AlwaysArgumentLabels) {
-      PrintOpts.ArgAndParamPrinting
-        = PrintOptions::ArgAndParamPrintingMode::BothAlways;
+    } else if (options::PrintInterfaceForDoc) {
+      return PrintOptions::printDocInterface();
+    } else {
+      auto PrintOpts = PrintOptions::printEverything();
+      PrintOpts.PrintTypesForDebugging = options::PrintForDebugging;
+      PrintOpts.FullyQualifiedTypes = options::FullyQualifiedTypes;
+      PrintOpts.FullyQualifiedTypesIfAmbiguous =
+        options::FullyQualifiedTypesIfAmbiguous;
+      PrintOpts.SynthesizeSugarOnTypes = options::SynthesizeSugarOnTypes;
+      PrintOpts.AbstractAccessors = options::AbstractAccessors;
+      PrintOpts.FunctionDefinitions = options::FunctionDefinitions;
+      PrintOpts.PrintExprs = options::Expressions;
+      PrintOpts.PreferTypeRepr = options::PreferTypeRepr;
+      PrintOpts.ExplodePatternBindingDecls = options::ExplodePatternBindingDecls;
+      PrintOpts.PrintImplicitAttrs = options::PrintImplicitAttrs;
+      PrintOpts.PrintAccess = options::PrintAccess;
+      PrintOpts.AccessFilter = options::AccessFilter;
+      PrintOpts.PrintDocumentationComments = !options::SkipDocumentationComments;
+      PrintOpts.SkipPrivateSystemDecls = options::SkipPrivateSystemDecls;
+      PrintOpts.SkipUnsafeCXXMethods = options::SkipUnsafeCXXMethods;
+      PrintOpts.SkipUnavailable = options::SkipUnavailable;
+      PrintOpts.SkipDeinit = options::SkipDeinit;
+      PrintOpts.SkipImports = options::SkipImports;
+      PrintOpts.SkipOverrides = options::SkipOverrides;
+      if (options::SkipParameterNames) {
+        PrintOpts.ArgAndParamPrinting
+          = PrintOptions::ArgAndParamPrintingMode::ArgumentOnly;
+      } else if (options::AlwaysArgumentLabels) {
+        PrintOpts.ArgAndParamPrinting
+          = PrintOptions::ArgAndParamPrintingMode::BothAlways;
+      }
+      return PrintOpts;
     }
-  }
+  }();
   if (options::SkipUnderscoredSystemProtocols)
     PrintOpts.SkipUnderscoredSystemProtocols = true;
   if (options::PrintOriginalSourceText)
@@ -4695,9 +4906,11 @@ int main(int argc, char *argv[]) {
         InitInvok, options::SourceFilename, options::CodeCompletionDiagnostics,
         options::CodeCompletionKeywords, options::CodeCompletionComments,
         options::CodeCompletionAnnotateResults,
+        options::CodeCompletionSortByName,
         options::CodeCompleteInitsInPostfixExpr,
         options::CodeCompletionAddCallWithNoDefaultArgs,
-        options::CodeCompletionSourceText);
+        options::CodeCompletionSourceText,
+        options::CodeCompletionVerifyUSRToDecl);
     break;
 
   case ActionType::CodeCompletion:
@@ -4710,9 +4923,11 @@ int main(int argc, char *argv[]) {
         options::CodeCompletionToken, options::CodeCompletionDiagnostics,
         options::CodeCompletionKeywords, options::CodeCompletionComments,
         options::CodeCompletionAnnotateResults,
+        options::CodeCompletionSortByName,
         options::CodeCompleteInitsInPostfixExpr,
         options::CodeCompletionAddCallWithNoDefaultArgs,
-        options::CodeCompletionSourceText);
+        options::CodeCompletionSourceText,
+        options::CodeCompletionVerifyUSRToDecl);
     break;
 
   case ActionType::REPLCodeCompletion:
@@ -4724,11 +4939,10 @@ int main(int argc, char *argv[]) {
       llvm::errs() << "token name required\n";
       return 1;
     }
-    ExitCode = doTypeContextInfo(InitInvok,
-                                  options::SourceFilename,
-                                  options::SecondSourceFilename,
-                                  options::CodeCompletionToken,
-                                  options::CodeCompletionDiagnostics);
+    ExitCode = doTypeContextInfo(InitInvok, options::SourceFilename,
+                                 options::SecondSourceFilename,
+                                 options::CodeCompletionToken,
+                                 options::CodeCompletionDiagnostics, PrintOpts);
     break;
 
   case ActionType::PrintExpressionTypes:
@@ -4742,12 +4956,20 @@ int main(int argc, char *argv[]) {
       llvm::errs() << "token name required\n";
       return 1;
     }
-    ExitCode = doConformingMethodList(InitInvok,
-                                      options::SourceFilename,
-                                      options::SecondSourceFilename,
-                                      options::CodeCompletionToken,
-                                      options::CodeCompletionDiagnostics,
-                                      options::ConformingMethodListExpectedTypes);
+    ExitCode = doConformingMethodList(
+        InitInvok, options::SourceFilename, options::SecondSourceFilename,
+        options::CodeCompletionToken, options::CodeCompletionDiagnostics,
+        options::ConformingMethodListExpectedTypes, PrintOpts);
+    break;
+
+  case ActionType::SignatureHelp:
+    if (options::CodeCompletionToken.empty()) {
+      llvm::errs() << "signature help token name required\n";
+      return 1;
+    }
+    ExitCode = doSignatureHelp(
+        InitInvok, options::SourceFilename, options::SecondSourceFilename,
+        options::CodeCompletionToken, options::CodeCompletionDiagnostics);
     break;
 
   case ActionType::SyntaxColoring:
@@ -4788,7 +5010,7 @@ int main(int argc, char *argv[]) {
     break;
   }
   case ActionType::PrintLocalTypes:
-    ExitCode = doPrintLocalTypes(InitInvok, options::ModuleToPrint);
+    ExitCode = doPrintLocalTypes(InitInvok, options::ModuleToPrint, PrintOpts);
     break;
 
   case ActionType::PrintModuleGroups:
@@ -4839,8 +5061,7 @@ int main(int argc, char *argv[]) {
   }
 
   case ActionType::PrintTypes:
-    ExitCode = doPrintTypes(InitInvok, options::SourceFilename,
-                            options::FullyQualifiedTypes);
+    ExitCode = doPrintTypes(InitInvok, options::SourceFilename, PrintOpts);
     break;
 
   case ActionType::PrintComments:
@@ -4875,12 +5096,12 @@ int main(int argc, char *argv[]) {
                                                 options::USR);
     break;
   case ActionType::ReconstructType:
-    ExitCode = doReconstructType(InitInvok, options::SourceFilename);
+    ExitCode = doReconstructType(InitInvok, options::SourceFilename, PrintOpts);
     break;
   case ActionType::Range:
     ExitCode = doPrintRangeInfo(InitInvok, options::SourceFilename,
                                 options::LineColumnPair,
-                                options::EndLineColumnPair);
+                                options::EndLineColumnPair, PrintOpts);
     break;
   case ActionType::PrintIndexedSymbols:
       if (options::ModuleToPrint.empty()) {
diff --git a/tools/swift-inspect/Sources/SwiftInspectLinux/PTrace.swift b/tools/swift-inspect/Sources/SwiftInspectLinux/PTrace.swift
index 50fec3f230919..e01dc69b097f1 100644
--- a/tools/swift-inspect/Sources/SwiftInspectLinux/PTrace.swift
+++ b/tools/swift-inspect/Sources/SwiftInspectLinux/PTrace.swift
@@ -33,24 +33,25 @@ public struct PTrace: ~Copyable {
   // process by calling cont().
   // NOTE: clients must use withPTracedProcess instead of direct initialization.
   fileprivate init(_ pid: pid_t) throws {
-    guard ptrace_attach(pid) != -1 else {
-      throw PTraceError.operationFailure(PTRACE_ATTACH, pid: pid)
+    self.pid = pid
+
+    guard ptrace_attach(self.pid) != -1 else {
+      throw PTraceError.operationFailure(PTRACE_ATTACH, pid: self.pid)
     }
 
     while true {
       var status: CInt = 0
-      let result = waitpid(pid, &status, 0)
+      let result = waitpid(self.pid, &status, 0)
       if result == -1 {
         if get_errno() == EINTR { continue }
-        throw PTraceError.waitFailure(pid: pid)
+        throw PTraceError.waitFailure(pid: self.pid)
       }
 
-      precondition(pid == result, "waitpid returned unexpected value \(result)")
+      precondition(self.pid == result,
+                   "waitpid returned unexpected value \(result)")
 
       if wIfStopped(status) { break }
     }
-
-    self.pid = pid
   }
 
   deinit { _ = ptrace_detach(self.pid) }
diff --git a/tools/swift-inspect/Sources/swift-inspect/Cleanup.swift b/tools/swift-inspect/Sources/swift-inspect/Cleanup.swift
new file mode 100644
index 0000000000000..dfc54bfaed7fd
--- /dev/null
+++ b/tools/swift-inspect/Sources/swift-inspect/Cleanup.swift
@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+/// A helper struct that manages the cleanup of some external resource.
+/// The value is stored as an Optional, but presented as a non-optional.
+/// Accessing the value before one has been set is a runtime error. The cleanup
+/// function is called on the value if one has been set, when setting a new
+/// value or when the struct is destroyed.
+struct Cleanup<T>: ~Copyable {
+  /// The underlying Optional storage for the value.
+  private var _value: T?
+
+  /// The wrapped value. A value must be set before any value is read here.
+  var value: T {
+    get {
+      _value!
+    }
+    set {
+      if let _value {
+        cleanup(_value)
+      }
+      _value = newValue
+    }
+  }
+
+  /// The function used to clean up the resource held by this struct.
+  let cleanup: (T) -> Void
+
+  init(cleanup: @escaping (T) -> Void) {
+    self._value = nil
+    self.cleanup = cleanup
+  }
+
+  deinit {
+    if let _value {
+      cleanup(_value)
+    }
+  }
+}
diff --git a/tools/swift-inspect/Sources/swift-inspect/DarwinRemoteProcess.swift b/tools/swift-inspect/Sources/swift-inspect/DarwinRemoteProcess.swift
index e86b0e47b31fc..c6a4088874aaa 100644
--- a/tools/swift-inspect/Sources/swift-inspect/DarwinRemoteProcess.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/DarwinRemoteProcess.swift
@@ -19,13 +19,25 @@ internal final class DarwinRemoteProcess: RemoteProcess {
   public typealias ProcessIdentifier = pid_t
   public typealias ProcessHandle = task_t
 
-  private var task: task_t
+  private var task = Cleanup<task_t> {
+    // task_stop_peeking does nothing if we didn't task_start_peeking first, so
+    // we can call it unconditionally.
+    task_stop_peeking($0)
+    mach_port_deallocate(mach_task_self_, $0)
+  }
+
   internal var processIdentifier: ProcessIdentifier
   internal lazy var processName = getProcessName(processId: processIdentifier) ?? "<unknown process>"
 
-  public var process: ProcessHandle { task }
-  public private(set) var context: SwiftReflectionContextRef!
-  private var symbolicator: CSSymbolicatorRef
+  public var process: ProcessHandle { task.value }
+  private var _context = Cleanup<SwiftReflectionContextRef> {
+    swift_reflection_destroyReflectionContext($0)
+  }
+  public var context: SwiftReflectionContextRef! { _context.value }
+
+  private var symbolicator = Cleanup<CSSymbolicatorRef> {
+    CSRelease($0)
+  }
 
   private var swiftCore: CSTypeRef
   private let swiftConcurrency: CSTypeRef
@@ -72,20 +84,33 @@ internal final class DarwinRemoteProcess: RemoteProcess {
   }
 
   func read(address: swift_addr_t, size: Int) -> UnsafeRawPointer? {
-    return task_peek(task, address, mach_vm_size_t(size))
+    return task_peek(task.value, address, mach_vm_size_t(size))
   }
 
-  func getAddr(symbolName: String) -> swift_addr_t {
+  func getAddr(symbolName: String) -> swift_addr_t? {
     // FIXME: use `__USER_LABEL_PREFIX__` instead of the hardcoded `_`.
     let fullName = "_\(symbolName)"
     var symbol = CSSymbolOwnerGetSymbolWithMangledName(swiftCore, fullName)
     if CSIsNull(symbol) {
       symbol = CSSymbolOwnerGetSymbolWithMangledName(swiftConcurrency, fullName)
     }
+    if CSIsNull(symbol) {
+      return nil
+    }
     let range = CSSymbolGetRange(symbol)
     return swift_addr_t(range.location)
   }
 
+  private func readGlobalVariable<T>(named name: String) -> T? {
+    guard let globalPointer = getAddr(symbolName: name) else {
+      return nil
+    }
+    guard let readPointer = read(address: globalPointer, size: MemoryLayout<T>.size) else {
+      return nil
+    }
+    return readPointer.load(as: T.self)
+  }
+
   static var Free: FreeFunction? { return nil }
 
   static var ReadBytes: ReadBytesFunction {
@@ -98,7 +123,7 @@ internal final class DarwinRemoteProcess: RemoteProcess {
   static var GetStringLength: GetStringLengthFunction {
     return { (context, address) in
       let process: DarwinRemoteProcess = DarwinRemoteProcess.fromOpaque(context!)
-      if let str = task_peek_string(process.task, address) {
+      if let str = task_peek_string(process.task.value, address) {
         return UInt64(strlen(str))
       }
       return 0
@@ -113,24 +138,25 @@ internal final class DarwinRemoteProcess: RemoteProcess {
         let buffer = UnsafeBufferPointer(start: $0, count: Int(length))
         return String(decoding: buffer, as: UTF8.self)
       }
-      return process.getAddr(symbolName: name)
+      return process.getAddr(symbolName: name) ?? 0
     }
   }
 
   init?(processId: ProcessIdentifier, forkCorpse: Bool) {
     processIdentifier = processId
-    var task: task_t = task_t()
-    let taskResult = task_for_pid(mach_task_self_, processId, &task)
+    var processTask: task_t = task_t()
+    let taskResult = task_for_pid(mach_task_self_, processId, &processTask)
     guard taskResult == KERN_SUCCESS else {
       print("unable to get task for pid \(processId): \(String(cString: mach_error_string(taskResult))) \(hex: taskResult)",
         to: &Std.err)
       return nil
     }
+    self.task.value = processTask
 
     // Consult with VMUProcInfo to determine if we should force forkCorpse.
     let forceForkCorpse: Bool
     if let procInfoClass = getVMUProcInfoClass() {
-      let procInfo = procInfoClass.init(task: task)
+      let procInfo = procInfoClass.init(task: self.task.value)
       forceForkCorpse = procInfo.shouldAnalyzeWithCorpse
     } else {
       // Default to not forcing forkCorpse.
@@ -141,11 +167,9 @@ internal final class DarwinRemoteProcess: RemoteProcess {
       var corpse = task_t()
       let maxRetry = 6
       for retry in 0..<maxRetry {
-        let corpseResult = task_generate_corpse(task, &corpse)
+        let corpseResult = task_generate_corpse(task.value, &corpse)
         if corpseResult == KERN_SUCCESS {
-          task_stop_peeking(task)
-          mach_port_deallocate(mach_task_self_, task)
-          task = corpse
+          task.value = corpse
           break
         }
         if corpseResult != KERN_RESOURCE_SHORTAGE || retry == maxRetry {
@@ -157,20 +181,19 @@ internal final class DarwinRemoteProcess: RemoteProcess {
       }
     }
 
-    self.task = task
+    self.symbolicator.value = CSSymbolicatorCreateWithTask(self.task.value)
+
+    self.swiftCore = CSSymbolicatorGetSymbolOwnerWithNameAtTime(
+        self.symbolicator.value, "libswiftCore.dylib", kCSNow)
+    self.swiftConcurrency = CSSymbolicatorGetSymbolOwnerWithNameAtTime(
+        self.symbolicator.value, "libswift_Concurrency.dylib", kCSNow)
 
-    self.symbolicator = CSSymbolicatorCreateWithTask(self.task)
-    self.swiftCore =
-        CSSymbolicatorGetSymbolOwnerWithNameAtTime(self.symbolicator,
-                                                   "libswiftCore.dylib", kCSNow)
     if CSIsNull(self.swiftCore) {
       print("pid \(processId) does not have libswiftCore.dylib loaded")
       return nil
     }
 
-    self.swiftConcurrency = CSSymbolicatorGetSymbolOwnerWithNameAtTime(
-      symbolicator, "libswift_Concurrency.dylib", kCSNow)
-    _ = task_start_peeking(self.task)
+    _ = task_start_peeking(self.task.value)
 
     guard let context =
         swift_reflection_createReflectionContextWithDataLayout(self.toOpaqueRef(),
@@ -181,23 +204,17 @@ internal final class DarwinRemoteProcess: RemoteProcess {
                                                                Self.GetSymbolAddress) else {
       return nil
     }
-    self.context = context
+    self._context.value = context
 
-    _ = CSSymbolicatorForeachSymbolOwnerAtTime(self.symbolicator, kCSNow, { owner in
+    _ = CSSymbolicatorForeachSymbolOwnerAtTime(self.symbolicator.value, kCSNow, { owner in
       let address = CSSymbolOwnerGetBaseAddress(owner)
       _ = swift_reflection_addImage(self.context, address)
     })
   }
 
-  deinit {
-    task_stop_peeking(self.task)
-    CSRelease(self.symbolicator)
-    mach_port_deallocate(mach_task_self_, self.task)
-  }
-
   func symbolicate(_ address: swift_addr_t) -> (module: String?, symbol: String?) {
     let symbol =
-        CSSymbolicatorGetSymbolWithAddressAtTime(self.symbolicator, address, kCSNow)
+        CSSymbolicatorGetSymbolWithAddressAtTime(self.symbolicator.value, address, kCSNow)
 
     let module = CSSymbolGetSymbolOwner(symbol)
     return (CSSymbolOwnerGetName(module), CSSymbolGetName(symbol))
@@ -206,7 +223,7 @@ internal final class DarwinRemoteProcess: RemoteProcess {
   internal func iterateHeap(_ body: (swift_addr_t, UInt64) -> Void) {
     withoutActuallyEscaping(body) {
       withUnsafePointer(to: $0) {
-        task_enumerate_malloc_blocks(self.task,
+        task_enumerate_malloc_blocks(self.task.value,
                                      UnsafeMutableRawPointer(mutating: $0),
                                      CUnsignedInt(MALLOC_PTR_IN_USE_RANGE_TYPE),
                                      { (task, context, type, ranges, count) in
@@ -220,6 +237,21 @@ internal final class DarwinRemoteProcess: RemoteProcess {
       }
     }
   }
+
+  internal func iteratePotentialMetadataPages(_ body: (swift_addr_t, UInt64) -> Void) {
+    if let initialPoolPointer: UInt = readGlobalVariable(named: "_swift_debug_allocationPoolPointer"),
+       let initialPoolSize: UInt = readGlobalVariable(named: "_swift_debug_allocationPoolSize") {
+      body(swift_addr_t(initialPoolPointer), UInt64(initialPoolSize));
+    }
+
+    if let pageSize: UInt = readGlobalVariable(named: "_swift_debug_metadataAllocatorPageSize") {
+      iterateHeap { address, size in
+        if size == pageSize {
+          body(address, size)
+        }
+      }
+    }
+  }
 }
 
 extension DarwinRemoteProcess {
@@ -264,14 +296,14 @@ extension DarwinRemoteProcess {
   }
 
   private func getThreadInfos() -> [ThreadInfo] {
-    guard let threads = PortList(task: self.task) else {
+    guard let threads = PortList(task: self.task.value) else {
       return []
     }
-    return threads.compactMap {
-      guard let info = getThreadInfo(thread: $0) else {
+    return threads.compactMap { t -> ThreadInfo? in
+      guard let info = getThreadInfo(thread: t) else {
         return nil
       }
-      guard let kernelObj = getKernelObject(task: mach_task_self_, port: $0) else {
+      guard let kernelObj = getKernelObject(task: mach_task_self_, port: t) else {
         return nil
       }
       return ThreadInfo(threadID: info.thread_id,
@@ -328,7 +360,7 @@ extension DarwinRemoteProcess {
   }
 
   internal func getThreadID(remotePort: thread_t) -> UInt64? {
-    guard let remoteThreadObj = getKernelObject(task: self.task, port: remotePort) else {
+    guard let remoteThreadObj = getKernelObject(task: self.task.value, port: remotePort) else {
       return nil
     }
     return threadInfos.first{ $0.kernelObject == remoteThreadObj }?.threadID
diff --git a/tools/swift-inspect/Sources/swift-inspect/LinuxRemoteProcess.swift b/tools/swift-inspect/Sources/swift-inspect/LinuxRemoteProcess.swift
index f7a352df59ba6..46c3bdc2c8af8 100644
--- a/tools/swift-inspect/Sources/swift-inspect/LinuxRemoteProcess.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/LinuxRemoteProcess.swift
@@ -154,5 +154,9 @@
     internal func iterateHeap(_ body: (swift_addr_t, UInt64) -> Void) {
       fatalError("heap iteration is not supported on Linux")
     }
+
+    internal func iteratePotentialMetadataPages(_ body: (swift_addr_t, UInt64) -> Void) {
+      fatalError("metadata page iteration is not supported on Linux")
+    }
   }
 #endif  // os(Linux)
diff --git a/tools/swift-inspect/Sources/swift-inspect/Operations/DumpConcurrency.swift b/tools/swift-inspect/Sources/swift-inspect/Operations/DumpConcurrency.swift
index 3e4a35eaf00a8..1e0442e64f476 100644
--- a/tools/swift-inspect/Sources/swift-inspect/Operations/DumpConcurrency.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/Operations/DumpConcurrency.swift
@@ -92,8 +92,8 @@ fileprivate class ConcurrencyDumper {
     self.process = process
 
     func getMetadata(symbolName: String) -> swift_reflection_ptr_t? {
-      let addr = process.getAddr(symbolName: symbolName)
-      if let ptr = process.read(address: addr, size: MemoryLayout<UInt>.size) {
+      if let addr = process.getAddr(symbolName: symbolName),
+         let ptr = process.read(address: addr, size: MemoryLayout<UInt>.size) {
         return swift_reflection_ptr_t(ptr.load(as: UInt.self))
       }
       return nil
diff --git a/tools/swift-inspect/Sources/swift-inspect/Operations/DumpGenericMetadata.swift b/tools/swift-inspect/Sources/swift-inspect/Operations/DumpGenericMetadata.swift
index d917b50685f26..ff780e06b11a7 100644
--- a/tools/swift-inspect/Sources/swift-inspect/Operations/DumpGenericMetadata.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/Operations/DumpGenericMetadata.swift
@@ -88,6 +88,18 @@ internal struct Output: TextOutputStream {
   }
 }
 
+internal func dumpJson(of: (any Encodable), outputFile: String?) throws {
+  let encoder = JSONEncoder()
+  encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
+  let data = try encoder.encode(of)
+  let jsonOutput = String(data: data, encoding: .utf8)!
+  if let outputFile = outputFile {
+    try jsonOutput.write(toFile: outputFile, atomically: true, encoding: .utf8)
+  } else {
+    print(jsonOutput)
+  }
+}
+
 internal struct DumpGenericMetadata: ParsableCommand {
   static let configuration = CommandConfiguration(
     abstract: "Print the target's generic metadata allocations.")
@@ -99,38 +111,22 @@ internal struct DumpGenericMetadata: ParsableCommand {
   var backtraceOptions: BacktraceOptions
 
   @OptionGroup()
-  var genericMetadataOptions: GenericMetadataOptions
+  var metadataOptions: MetadataOptions
+  
+  @Flag(help: "Show allocations in mangled form")
+  var mangled: Bool = false
+
+  @Flag(help: "Scan for data that looks like Swift type metadata.")
+  var scanSearch: Bool = false
 
   func run() throws {
     disableStdErrBuffer()
     var metadataSummary = [String: MetadataSummary]()
     var allProcesses = [ProcessMetadata]()
     try inspect(options: options) { process in
-      let allocations: [swift_metadata_allocation_t] =
-          try process.context.allocations.sorted()
-
-      let stacks: [swift_reflection_ptr_t:[swift_reflection_ptr_t]] =
-          backtraceOptions.style == nil
-          ? [swift_reflection_ptr_t:[swift_reflection_ptr_t]]()
-          : try process.context.allocationStacks
-
-      let generics: [Metadata] = allocations.compactMap { allocation -> Metadata? in
-        let pointer = swift_reflection_allocationMetadataPointer(process.context, allocation)
-        if pointer == 0 { return nil }
-        let allocation = allocations.last(where: { pointer >= $0.ptr && pointer < $0.ptr + swift_reflection_ptr_t($0.size) })
-        let garbage = (allocation == nil && swift_reflection_ownsAddressStrict(process.context, UInt(pointer)) == 0)
-        var currentBacktrace: String?
-        if let style = backtraceOptions.style, let allocation, let stack = stacks[allocation.ptr] {
-          currentBacktrace = backtrace(stack, style: style, process.symbolicate)
-        }
-
-        return Metadata(ptr: pointer,
-                        allocation: allocation,
-                        name: process.context.name(type: pointer, mangled: genericMetadataOptions.mangled) ?? "<unknown>",
-                        isArrayOfClass: process.context.isArrayOfClass(pointer),
-                        garbage: garbage,
-                        backtrace: currentBacktrace)
-      } // generics
+      let generics = scanSearch
+          ? try metadataFromScanning(process: process)
+          : try metadataFromAllocations(process: process)
 
       // Update summary
       generics.forEach { metadata in
@@ -146,30 +142,84 @@ internal struct DumpGenericMetadata: ParsableCommand {
         }
       }
 
-      if genericMetadataOptions.json {
+      if metadataOptions.json {
         let processMetadata = ProcessMetadata(name: process.processName,
                                               pid: process.processIdentifier as! ProcessIdentifier,
                                               metadata: generics)
         allProcesses.append(processMetadata)
-      } else if !genericMetadataOptions.summary {
+      } else if !metadataOptions.summary {
         try dumpText(process: process, generics: generics)
         }
     } // inspect
 
-    if genericMetadataOptions.json {
-      if genericMetadataOptions.summary {
-        try dumpJson(of: metadataSummary)
+    if metadataOptions.json {
+      if metadataOptions.summary {
+        try dumpJson(of: metadataSummary, outputFile: metadataOptions.outputFile)
       } else {
-        try dumpJson(of: allProcesses)
+        try dumpJson(of: allProcesses, outputFile: metadataOptions.outputFile)
         }
-    } else if genericMetadataOptions.summary {
+    } else if metadataOptions.summary {
       try dumpTextSummary(of: metadataSummary)
     }
   }
 
+  private func metadataFromAllocations(process: any RemoteProcess) throws -> [Metadata] {
+    let allocations: [swift_metadata_allocation_t] =
+        try process.context.allocations.sorted()
+
+    let stacks: [swift_reflection_ptr_t:[swift_reflection_ptr_t]] =
+        backtraceOptions.style == nil
+        ? [swift_reflection_ptr_t:[swift_reflection_ptr_t]]()
+        : try process.context.allocationStacks
+
+    return allocations.compactMap { allocation -> Metadata? in
+      let pointer = swift_reflection_allocationMetadataPointer(process.context, allocation)
+      if pointer == 0 { return nil }
+      let allocation = allocations.last(where: { pointer >= $0.ptr && pointer < $0.ptr + swift_reflection_ptr_t($0.size) })
+      let garbage = (allocation == nil && swift_reflection_ownsAddressStrict(process.context, UInt(pointer)) == 0)
+      var currentBacktrace: String?
+      if let style = backtraceOptions.style, let allocation, let stack = stacks[allocation.ptr] {
+        currentBacktrace = backtrace(stack, style: style, process.symbolicate)
+      }
+
+      return Metadata(ptr: pointer,
+                      allocation: allocation,
+                      name: process.context.name(type: pointer, mangled: mangled) ?? "<unknown>",
+                      isArrayOfClass: process.context.isArrayOfClass(pointer),
+                      garbage: garbage,
+                      backtrace: currentBacktrace)
+    }
+  }
+
+  private func metadataFromScanning(process: any RemoteProcess) throws -> [Metadata] {
+    var metadata: [Metadata] = []
+
+    func scanMemory(address: swift_addr_t, size: UInt64) {
+      let convertedAddress = swift_reflection_ptr_t(address)
+      for candidate in stride(from: convertedAddress,
+                              to: convertedAddress + swift_reflection_ptr_t(size),
+                              by: MemoryLayout<UInt>.size) {
+        guard let name = process.context.name(type: candidate, mangled: mangled) else {
+          continue
+        }
+        let m = Metadata(ptr: candidate,
+                         allocation: nil,
+                         name: name,
+                         isArrayOfClass: process.context.isArrayOfClass(candidate),
+                         garbage: false,
+                         backtrace: nil)
+        metadata.append(m)
+      }
+    }
+
+    process.iteratePotentialMetadataPages(scanMemory)
+
+    return metadata
+  }
+
   private func dumpText(process: any RemoteProcess, generics: [Metadata]) throws {
     var erroneousMetadata: [(ptr: swift_reflection_ptr_t, name: String)] = []
-    var output = try Output(genericMetadataOptions.outputFile)
+    var output = try Output(metadataOptions.outputFile)
     print("\(process.processName)(\(process.processIdentifier)):\n", to: &output)
     print("Address", "Allocation", "Size", "Offset", "isArrayOfClass", "Name", separator: "\t", to: &output)
     generics.forEach {
@@ -198,20 +248,8 @@ internal struct DumpGenericMetadata: ParsableCommand {
     print("", to: &output)
   }
 
-  private func dumpJson(of: (any Encodable)) throws {
-    let encoder = JSONEncoder()
-    encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
-    let data = try encoder.encode(of)
-    let jsonOutput = String(data: data, encoding: .utf8)!
-    if let outputFile = genericMetadataOptions.outputFile {
-      try jsonOutput.write(toFile: outputFile, atomically: true, encoding: .utf8)
-    } else {
-      print(jsonOutput)
-    }
-  }
-
   private func dumpTextSummary(of: [String: MetadataSummary]) throws {
-    var output = try Output(genericMetadataOptions.outputFile)
+    var output = try Output(metadataOptions.outputFile)
     print("Size", "Owners", "Name", separator: "\t", to: &output)
     var totalSize = 0
     var unknownSize = 0
diff --git a/tools/swift-inspect/Sources/swift-inspect/Operations/DumpRawMetadata.swift b/tools/swift-inspect/Sources/swift-inspect/Operations/DumpRawMetadata.swift
index 5d2e11edce451..1be15984c872c 100644
--- a/tools/swift-inspect/Sources/swift-inspect/Operations/DumpRawMetadata.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/Operations/DumpRawMetadata.swift
@@ -12,6 +12,23 @@
 
 import ArgumentParser
 import SwiftRemoteMirror
+import Foundation
+
+private struct AllocatorTagTotal: Encodable {
+  let name: String
+  let tag: Int
+  var totalBytes: Int
+}
+
+private struct Summary: Encodable {
+  let totalBytesAllocated: Int
+  let allocatorTags: [AllocatorTagTotal]
+}
+
+private struct RawMetadataOutput: Encodable {
+  let allocationList: [swift_metadata_allocation_t]?
+  let summary: Summary?
+}
 
 internal struct DumpRawMetadata: ParsableCommand {
   static let configuration = CommandConfiguration(
@@ -22,8 +39,15 @@ internal struct DumpRawMetadata: ParsableCommand {
 
   @OptionGroup()
   var backtraceOptions: BacktraceOptions
+  
+ @OptionGroup()
+  var metadataOptions: MetadataOptions
 
   func run() throws {
+    var allocatorTagTotals = [Int: AllocatorTagTotal]()
+    var total: Int = 0
+    var allocationList: [swift_metadata_allocation_t] = []
+
     try inspect(options: options) { process in
       let stacks: [swift_reflection_ptr_t:[swift_reflection_ptr_t]]? =
           backtraceOptions.style == nil
@@ -33,6 +57,18 @@ internal struct DumpRawMetadata: ParsableCommand {
       try process.context.allocations.forEach { allocation in
         let name: String = process.context.name(allocation: allocation.tag) ??  "<unknown>"
         print("Metadata allocation at: \(hex: allocation.ptr) size: \(allocation.size) tag: \(allocation.tag) (\(name))")
+        
+        if metadataOptions.summary {
+          if var allocatorTagTotal = allocatorTagTotals[Int(allocation.tag)] {
+            allocatorTagTotal.totalBytes += allocation.size
+            allocatorTagTotals[Int(allocation.tag)] = allocatorTagTotal
+          } else {
+            allocatorTagTotals[Int(allocation.tag)] = AllocatorTagTotal(name: name, tag: Int(allocation.tag), totalBytes: allocation.size)
+          }
+          
+          total += allocation.size
+        }
+        allocationList.append(allocation)
         if let style = backtraceOptions.style {
           if let stack = stacks?[allocation.ptr] {
             print(backtrace(stack, style: style, process.symbolicate))
@@ -42,5 +78,27 @@ internal struct DumpRawMetadata: ParsableCommand {
         }
       }
     }
+    
+    if metadataOptions.json {
+      let jsonStruct: RawMetadataOutput
+      let allocatorTagArray = Array(allocatorTagTotals.values).sorted(by: {$0.totalBytes > $1.totalBytes})
+      
+      if metadataOptions.summary {
+        let summaryStruct = Summary(totalBytesAllocated: total, allocatorTags: allocatorTagArray)
+        jsonStruct = RawMetadataOutput(allocationList: allocationList, summary: summaryStruct)
+      } else {
+        jsonStruct = RawMetadataOutput(allocationList: allocationList, summary: nil)
+      }
+      try dumpJson(of: jsonStruct, outputFile: metadataOptions.outputFile)
+    } else if metadataOptions.summary {
+      let allocatorTagArray = Array(allocatorTagTotals.values).sorted(by: {$0.totalBytes > $1.totalBytes})
+      
+      print("Metadata allocation summary:")
+      for tag in allocatorTagArray {
+        print("Tag: \(tag.tag) (\(tag.name)) Size: \(tag.totalBytes) bytes")
+      }
+      
+      print("\nTotal bytes allocated: \(total)")
+    }
   }
 }
diff --git a/tools/swift-inspect/Sources/swift-inspect/Process.swift b/tools/swift-inspect/Sources/swift-inspect/Process.swift
index 9317f5d0957b2..f0d41fe27a2cb 100644
--- a/tools/swift-inspect/Sources/swift-inspect/Process.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/Process.swift
@@ -80,7 +80,7 @@ internal func getAllProcesses(options: UniversalOptions) -> [ProcessIdentifier]?
   }
   let newCount = bufferSize / kinfo_stride
   if count > newCount {
-    buffer.dropLast(count - newCount)
+    buffer.removeLast(count - newCount)
   }
   let sorted = buffer.sorted { first, second in
     first.kp_proc.p_pid > second.kp_proc.p_pid
diff --git a/tools/swift-inspect/Sources/swift-inspect/RemoteMirror+Extensions.swift b/tools/swift-inspect/Sources/swift-inspect/RemoteMirror+Extensions.swift
index 3d4b9fee61b58..34ee8768f6b49 100644
--- a/tools/swift-inspect/Sources/swift-inspect/RemoteMirror+Extensions.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/RemoteMirror+Extensions.swift
@@ -79,6 +79,18 @@ extension SwiftReflectionContextRef {
     let typeref = swift_reflection_typeRefForMetadata(self, UInt(type))
     if typeref == 0 { return nil }
 
+    let info = swift_reflection_infoForTypeRef(self, typeref)
+    let nominalKinds = [
+      SWIFT_STRUCT,
+      SWIFT_TUPLE,
+      SWIFT_NO_PAYLOAD_ENUM,
+      SWIFT_SINGLE_PAYLOAD_ENUM,
+      SWIFT_MULTI_PAYLOAD_ENUM,
+      SWIFT_CLASS_INSTANCE,
+      SWIFT_ARRAY
+    ]
+    guard nominalKinds.contains(info.Kind) else { return nil }
+
     guard let name = swift_reflection_copyNameForTypeRef(self, typeref, mangled) else {
       return nil
     }
diff --git a/tools/swift-inspect/Sources/swift-inspect/RemoteProcess.swift b/tools/swift-inspect/Sources/swift-inspect/RemoteProcess.swift
index aac5decc93a1a..5452395c8f5ef 100644
--- a/tools/swift-inspect/Sources/swift-inspect/RemoteProcess.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/RemoteProcess.swift
@@ -43,6 +43,7 @@ internal protocol RemoteProcess: AnyObject {
 
   func symbolicate(_ address: swift_addr_t) -> (module: String?, symbol: String?)
   func iterateHeap(_ body: (swift_addr_t, UInt64) -> Void)
+  func iteratePotentialMetadataPages(_ body: (swift_addr_t, UInt64) -> Void)
 }
 
 extension RemoteProcess {
diff --git a/tools/swift-inspect/Sources/swift-inspect/WindowsRemoteProcess.swift b/tools/swift-inspect/Sources/swift-inspect/WindowsRemoteProcess.swift
index b2f9788547af1..5a49e183c6aa1 100644
--- a/tools/swift-inspect/Sources/swift-inspect/WindowsRemoteProcess.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/WindowsRemoteProcess.swift
@@ -397,6 +397,10 @@ internal final class WindowsRemoteProcess: RemoteProcess {
     }
   }
 
+  internal func iteratePotentialMetadataPages(_ body: (swift_addr_t, UInt64) -> Void) {
+    fatalError("metadata page iteration is not supported on Windows")
+  }
+
   private func allocateDllPathRemote() -> UnsafeMutableRawPointer? {
     URL(fileURLWithPath: ProcessInfo.processInfo.arguments[0])
       .deletingLastPathComponent()
diff --git a/tools/swift-inspect/Sources/swift-inspect/main.swift b/tools/swift-inspect/Sources/swift-inspect/main.swift
index d54da9bc1f0e5..e02d1e812c55f 100644
--- a/tools/swift-inspect/Sources/swift-inspect/main.swift
+++ b/tools/swift-inspect/Sources/swift-inspect/main.swift
@@ -62,10 +62,7 @@ internal struct BacktraceOptions: ParsableArguments {
   }
 }
 
-internal struct GenericMetadataOptions: ParsableArguments {
-  @Flag(help: "Show allocations in mangled form")
-  var mangled: Bool = false
-
+internal struct MetadataOptions: ParsableArguments {
   @Flag(help: "Output JSON")
   var json: Bool = false
 
diff --git a/tools/swift-reflection-dump/swift-reflection-dump.cpp b/tools/swift-reflection-dump/swift-reflection-dump.cpp
index dba4352311f20..100af2eb203c7 100644
--- a/tools/swift-reflection-dump/swift-reflection-dump.cpp
+++ b/tools/swift-reflection-dump/swift-reflection-dump.cpp
@@ -79,11 +79,13 @@ static llvm::cl::opt<std::string>
                  llvm::cl::desc("Architecture to inspect in the binary"),
                  llvm::cl::Required);
 
-#if SWIFT_OBJC_INTEROP
 static llvm::cl::opt<bool> DisableObjCInterop(
     "no-objc-interop",
-    llvm::cl::desc("Disable Objective-C interoperability support"));
+    llvm::cl::desc("Disable Objective-C interoperability support"
+#if SWIFT_OBJC_INTEROP
+                   " (not supported)"
 #endif
+                   ));
 } // end namespace options
 
 static int doDumpReflectionSections(ArrayRef<std::string> BinaryFilenames,
diff --git a/tools/swift-reflection-fuzzer/swift-reflection-fuzzer.cpp b/tools/swift-reflection-fuzzer/swift-reflection-fuzzer.cpp
index 2226c92f40f2d..041e595048838 100644
--- a/tools/swift-reflection-fuzzer/swift-reflection-fuzzer.cpp
+++ b/tools/swift-reflection-fuzzer/swift-reflection-fuzzer.cpp
@@ -120,20 +120,20 @@ class ObjectMemoryReader : public MemoryReader {
   }
 
   RemoteAddress getSymbolAddress(const std::string &name) override {
-    return RemoteAddress(nullptr);
+    return RemoteAddress();
   }
 
   bool isAddressValid(RemoteAddress addr, uint64_t size) const { return true; }
 
   ReadBytesResult readBytes(RemoteAddress address, uint64_t size) override {
-    return ReadBytesResult((const void *)address.getAddressData(),
+    return ReadBytesResult((const void *)address.getRawAddress(),
                            [](const void *) {});
   }
 
   bool readString(RemoteAddress address, std::string &dest) override {
     if (!isAddressValid(address, 1))
       return false;
-    auto cString = StringRef((const char *)address.getAddressData());
+    auto cString = StringRef((const char *)address.getRawAddress());
     dest.append(cString.begin(), cString.end());
     return true;
   }
@@ -142,7 +142,8 @@ class ObjectMemoryReader : public MemoryReader {
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
   auto reader = std::make_shared<ObjectMemoryReader>();
   NativeReflectionContext context(std::move(reader));
-  context.addImage(RemoteAddress(Data));
+  context.addImage(
+      RemoteAddress((uint64_t)Data, RemoteAddress::DefaultAddressSpace));
   context.getBuilder().dumpAllSections<WithObjCInterop, sizeof(uintptr_t)>(std::cout);
   return 0; // Non-zero return values are reserved for future use.
 }
diff --git a/tools/swift-remoteast-test/CMakeLists.txt b/tools/swift-remoteast-test/CMakeLists.txt
index 59ef68626d206..bce2e988e3e8a 100644
--- a/tools/swift-remoteast-test/CMakeLists.txt
+++ b/tools/swift-remoteast-test/CMakeLists.txt
@@ -1,12 +1,14 @@
 add_swift_host_tool(swift-remoteast-test
   swift-remoteast-test.cpp
   SWIFT_COMPONENT testsuite-tools
+  HAS_SWIFT_MODULES
   THINLTO_LD64_ADD_FLTO_CODEGEN_ONLY
 )
 target_link_libraries(swift-remoteast-test
                       PRIVATE
                         swiftFrontendTool
-                        swiftRemoteAST)
+                        swiftRemoteAST
+                        swiftCompilerModules)
 set_target_properties(swift-remoteast-test PROPERTIES ENABLE_EXPORTS 1)
 
 # If building as part of clang, make sure the headers are installed.
diff --git a/tools/swift-remoteast-test/swift-remoteast-test.cpp b/tools/swift-remoteast-test/swift-remoteast-test.cpp
index 9b172eb8ab394..84df4516611a6 100644
--- a/tools/swift-remoteast-test/swift-remoteast-test.cpp
+++ b/tools/swift-remoteast-test/swift-remoteast-test.cpp
@@ -21,6 +21,7 @@
 #include "swift/FrontendTool/FrontendTool.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/LLVMInitialize.h"
+#include "swift/Basic/InitializeSwiftModules.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
@@ -77,8 +78,8 @@ printMetadataType(const Metadata *typeMetadata) {
   auto &remoteAST = getRemoteASTContext();
   auto &out = llvm::outs();
 
-  auto result =
-    remoteAST.getTypeForRemoteTypeMetadata(RemoteAddress(typeMetadata));
+  auto result = remoteAST.getTypeForRemoteTypeMetadata(RemoteAddress(
+      (uint64_t)typeMetadata, RemoteAddress::DefaultAddressSpace));
   if (result) {
     out << "found type: ";
     result.getValue().print(out);
@@ -95,8 +96,8 @@ printHeapMetadataType(void *object) {
   auto &remoteAST = getRemoteASTContext();
   auto &out = llvm::outs();
 
-  auto metadataResult =
-    remoteAST.getHeapMetadataForObject(RemoteAddress(object));
+  auto metadataResult = remoteAST.getHeapMetadataForObject(
+      RemoteAddress((uint64_t)object, RemoteAddress::DefaultAddressSpace));
   if (!metadataResult) {
     out << metadataResult.getFailure().render() << '\n';
     return;
@@ -120,8 +121,8 @@ static void printMemberOffset(const Metadata *typeMetadata,
   auto &out = llvm::outs();
 
   // The first thing we have to do is get the type.
-  auto typeResult =
-    remoteAST.getTypeForRemoteTypeMetadata(RemoteAddress(typeMetadata));
+  auto typeResult = remoteAST.getTypeForRemoteTypeMetadata(RemoteAddress(
+      (uint64_t)typeMetadata, RemoteAddress::DefaultAddressSpace));
   if (!typeResult) {
     out << "failed to find type: " << typeResult.getFailure().render() << '\n';
     return;
@@ -130,7 +131,9 @@ static void printMemberOffset(const Metadata *typeMetadata,
   Type type = typeResult.getValue();
 
   RemoteAddress address =
-    (passMetadata ? RemoteAddress(typeMetadata) : RemoteAddress(nullptr));
+      (passMetadata ? RemoteAddress((uint64_t)typeMetadata,
+                                    RemoteAddress::DefaultAddressSpace)
+                    : RemoteAddress());
 
   auto offsetResult =
     remoteAST.getOffsetOfMember(type, address, memberName);
@@ -170,8 +173,8 @@ printDynamicTypeAndAddressForExistential(void *object,
 
   // First, retrieve the static type of the existential, so we can understand
   // which kind of existential this is.
-  auto staticTypeResult =
-      remoteAST.getTypeForRemoteTypeMetadata(RemoteAddress(typeMetadata));
+  auto staticTypeResult = remoteAST.getTypeForRemoteTypeMetadata(RemoteAddress(
+      (uint64_t)typeMetadata, RemoteAddress::DefaultAddressSpace));
   if (!staticTypeResult) {
     out << "failed to resolve static type: "
         << staticTypeResult.getFailure().render() << '\n';
@@ -180,7 +183,8 @@ printDynamicTypeAndAddressForExistential(void *object,
 
   // OK, we can reconstruct the dynamic type and the address now.
   auto result = remoteAST.getDynamicTypeAndAddressForExistential(
-      RemoteAddress(object), staticTypeResult.getValue());
+      RemoteAddress((uint64_t)object, RemoteAddress::DefaultAddressSpace),
+      staticTypeResult.getValue());
   if (result) {
     out << "found type: ";
     result.getValue().InstanceType.print(out);
@@ -221,6 +225,8 @@ int main(int argc, const char *argv[]) {
   forwardedArgs.push_back("-interpret");
   assert(forwardedArgs.size() == numForwardedArgs);
 
+  initializeSwiftModules();
+
   Observer observer;
   return performFrontend(forwardedArgs, argv[0], (void*) &printMetadataType,
                          &observer);
diff --git a/tools/swift-scan-test/swift-scan-test.cpp b/tools/swift-scan-test/swift-scan-test.cpp
index 21ef7ad000b70..7509d19c4d5e9 100644
--- a/tools/swift-scan-test/swift-scan-test.cpp
+++ b/tools/swift-scan-test/swift-scan-test.cpp
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
+// Copyright (c) 2022 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -17,6 +17,7 @@
 #include "swift-c/DependencyScan/DependencyScan.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/FileTypes.h"
+#include "swift/Basic/LLVMInitialize.h"
 #include "swift/DependencyScan/DependencyScanJSON.h"
 #include "swift/DependencyScan/StringUtils.h"
 #include "llvm/ADT/StringExtras.h"
@@ -283,6 +284,8 @@ createArgs(ArrayRef<std::string> Cmd, StringSaver &Saver, Actions Action) {
 }
 
 int main(int argc, char *argv[]) {
+  PROGRAM_START(argc, argv);
+
   llvm::cl::HideUnrelatedOptions(Category);
   llvm::cl::ParseCommandLineOptions(argc, argv,
                                     "Test libSwiftScan interfaces\n");
diff --git a/unittests/AST/ASTDumperTests.cpp b/unittests/AST/ASTDumperTests.cpp
index 042ff30fd2539..9cb9f6fa83381 100644
--- a/unittests/AST/ASTDumperTests.cpp
+++ b/unittests/AST/ASTDumperTests.cpp
@@ -26,15 +26,14 @@ TEST(ASTDumper, ArchetypeType) {
   TestContext C;
   auto &ctx = C.Ctx;
 
-  auto *genericParamTy = GenericTypeParamType::getType(0, 0, ctx);
-  auto sig = buildGenericSignature(ctx, nullptr, {genericParamTy}, {},
+  auto sig = buildGenericSignature(ctx, nullptr, {ctx.TheSelfType}, {},
                                    /*allowInverses=*/true);
 
   TypeBase *archetype = nullptr;
   {
     llvm::SmallVector<ProtocolDecl *> protocols;
     archetype = PrimaryArchetypeType::getNew(ctx, sig.getGenericEnvironment(),
-                                             genericParamTy, protocols, Type(),
+                                             ctx.TheSelfType, protocols, Type(),
                                              nullptr);
   }
 
diff --git a/unittests/AST/AvailabilityDomainTests.cpp b/unittests/AST/AvailabilityDomainTests.cpp
index 5da57c8f9d4d2..b10aaff753f3c 100644
--- a/unittests/AST/AvailabilityDomainTests.cpp
+++ b/unittests/AST/AvailabilityDomainTests.cpp
@@ -23,7 +23,7 @@ class AvailabilityDomainLattice : public ::testing::Test {
     return AvailabilityDomain::forPlatform(kind);
   }
   AvailabilityDomain Universal = AvailabilityDomain::forUniversal();
-  AvailabilityDomain Swift = AvailabilityDomain::forSwiftLanguage();
+  AvailabilityDomain Swift = AvailabilityDomain::forSwiftLanguageMode();
   AvailabilityDomain Package = AvailabilityDomain::forPackageDescription();
   AvailabilityDomain Embedded = AvailabilityDomain::forEmbedded();
   AvailabilityDomain macOS = domainForPlatform(PlatformKind::macOS);
@@ -53,7 +53,7 @@ TEST_F(AvailabilityDomainLattice, Contains) {
     EXPECT_TRUE(Universal.contains(domain));
 
     // These domains only contain themselves.
-    EXPECT_EQ(Swift.contains(domain), domain.isSwiftLanguage());
+    EXPECT_EQ(Swift.contains(domain), domain.isSwiftLanguageMode());
     EXPECT_EQ(Package.contains(domain), domain.isPackageDescription());
     EXPECT_EQ(Embedded.contains(domain), domain.isEmbedded());
   }
diff --git a/unittests/AST/CMakeLists.txt b/unittests/AST/CMakeLists.txt
index e44834c78aeca..5ec61e06fa26b 100644
--- a/unittests/AST/CMakeLists.txt
+++ b/unittests/AST/CMakeLists.txt
@@ -8,6 +8,7 @@ add_swift_unittest(SwiftASTTests
   DiagnosticBehaviorTests.cpp
   DiagnosticConsumerTests.cpp
   DiagnosticGroupsTests.cpp
+  DiagnosticFormattingTests.cpp
   DiagnosticInfoTests.cpp
   SourceLocTests.cpp
   TestContext.cpp
diff --git a/unittests/AST/DiagnosticFormattingTests.cpp b/unittests/AST/DiagnosticFormattingTests.cpp
new file mode 100644
index 0000000000000..860df7ca0c445
--- /dev/null
+++ b/unittests/AST/DiagnosticFormattingTests.cpp
@@ -0,0 +1,42 @@
+//===--- DiagnosticFormattingTests.cpp ------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/AST/Attr.h"
+#include "swift/AST/DiagnosticEngine.h"
+#include "swift/Basic/SourceManager.h"
+#include "llvm/Support/raw_ostream.h"
+#include "gtest/gtest.h"
+
+using namespace swift;
+
+namespace {
+
+static void testCase(StringRef formatStr, StringRef resultStr,
+                     ArrayRef<DiagnosticArgument> args) {
+  SourceManager sourceMgr;
+  DiagnosticEngine diags(sourceMgr);
+
+  std::string actualResultStr;
+  llvm::raw_string_ostream os(actualResultStr);
+
+  diags.formatDiagnosticText(os, formatStr, args);
+
+  ASSERT_EQ(actualResultStr, resultStr.str());
+}
+
+TEST(DiagnosticFormatting, TypeAttribute) {
+  EscapingTypeAttr attr{SourceLoc(), SourceLoc()};
+  testCase("%0", "'@escaping'", {&attr});
+  testCase("%kind0", "attribute 'escaping'", {&attr});
+}
+
+} // end anonymous namespace
diff --git a/unittests/Basic/SourceManagerTest.cpp b/unittests/Basic/SourceManagerTest.cpp
index 44e4bf012ad1a..24aeebd6c12ed 100644
--- a/unittests/Basic/SourceManagerTest.cpp
+++ b/unittests/Basic/SourceManagerTest.cpp
@@ -22,7 +22,7 @@ static std::vector<SourceLoc> tokenize(SourceManager &SM, StringRef Source) {
   unsigned ID = SM.addMemBufferCopy(Source);
   const MemoryBuffer *Buf = SM.getLLVMSourceMgr().getMemoryBuffer(ID);
 
-  SourceLoc BeginLoc(SMLoc::getFromPointer(Buf->getBuffer().begin()));
+  auto BeginLoc = SourceLoc::getFromPointer(Buf->getBuffer().begin());
   std::vector<SourceLoc> Result;
   Result.push_back(BeginLoc);
   for (unsigned i = 1, e = Source.size(); i != e; ++i) {
diff --git a/unittests/DependencyScan/ModuleDeps.cpp b/unittests/DependencyScan/ModuleDeps.cpp
index 27c8edf24e98a..e932fd8bf937a 100644
--- a/unittests/DependencyScan/ModuleDeps.cpp
+++ b/unittests/DependencyScan/ModuleDeps.cpp
@@ -14,6 +14,8 @@
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/Platform.h"
 #include "swift/DependencyScan/DependencyScanImpl.h"
+#include "clang/Frontend/SerializedDiagnosticReader.h"
+#include "clang/Frontend/SerializedDiagnostics.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/Host.h"
@@ -175,7 +177,7 @@ export *\n\
   for (auto &command : CommandStrArr) {
     Command.push_back(command.c_str());
   }
-  auto DependenciesOrErr = ScannerTool.getDependencies(Command, {}, {});
+  auto DependenciesOrErr = ScannerTool.getDependencies(Command, {});
   ASSERT_FALSE(DependenciesOrErr.getError());
   auto Dependencies = DependenciesOrErr.get();
   // TODO: Output/verify dependency graph correctness
@@ -244,12 +246,125 @@ public func overlayFuncA() { }\n"));
     CommandB.push_back(command.c_str());
   }
 
-  auto ScanDiagnosticConsumer = std::make_shared<DependencyScanDiagnosticCollector>();
-  auto instanceA = ScannerTool.initCompilerInstanceForScan(CommandA, {}, ScanDiagnosticConsumer);
-  auto instanceB = ScannerTool.initCompilerInstanceForScan(CommandB, {}, ScanDiagnosticConsumer);
+  std::vector<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+      InitializationDiagnostics;
+  auto queryAContext = ScannerTool.createScanQueryContext(CommandA, {},
+                                                          InitializationDiagnostics);
+  auto queryBContext = ScannerTool.createScanQueryContext(CommandB, {},
+                                                          InitializationDiagnostics);
   // Ensure that scans that only differ in module name have distinct scanning context hashes
-  ASSERT_NE(instanceA->ScanInstance.get()->getInvocation().getModuleScanningHash(),
-            instanceB->ScanInstance.get()->getInvocation().getModuleScanningHash());
+  ASSERT_NE(queryAContext->ScanInstance.get()->getInvocation().getModuleScanningHash(),
+            queryBContext->ScanInstance.get()->getInvocation().getModuleScanningHash());
+}
+
+namespace {
+class DiagnosticChecker : public clang::serialized_diags::SerializedDiagnosticReader {
+public:
+  std::vector<std::string> errorMessages;
+  std::vector<std::string> warningMessages;
+
+protected:
+  std::error_code visitDiagnosticRecord(
+      unsigned Severity, const clang::serialized_diags::Location &Location,
+      unsigned Category, unsigned Flag, StringRef Message) override {
+      switch (static_cast<clang::serialized_diags::Level>(Severity)) {
+        case clang::serialized_diags::Warning:
+          warningMessages.push_back(Message.str());
+          break;
+        case clang::serialized_diags::Error:
+          errorMessages.push_back(Message.str());
+          break;
+        default:
+          break;
+      }
+      return std::error_code();
+  }
+};
+}
+
+
+TEST_F(ScanTest, TestSerializedDiagnosticOutput) {
+  SmallString<256> tempDir;
+  ASSERT_FALSE(llvm::sys::fs::createUniqueDirectory(
+      "ScanTest.TestSerializedDiagnosticOutput", tempDir));
+  SWIFT_DEFER { llvm::sys::fs::remove_directories(tempDir); };
+
+  // Create test input file
+  std::string TestPathStr = createFilename(tempDir, "foo.swift");
+  ASSERT_FALSE(emitFileWithContents(tempDir, "foo.swift", "import A\n\
+#warning(\"This is a warning\")\n"));
+
+  // Create include directory
+  std::string SwiftDirPath = createFilename(tempDir, "Swift");
+  ASSERT_FALSE(llvm::sys::fs::create_directory(SwiftDirPath));
+
+  // Create output directory
+  std::string OutputDirPath = createFilename(tempDir, "Output");
+  ASSERT_FALSE(llvm::sys::fs::create_directory(OutputDirPath));
+  std::string SerializedDiagnosticsOutputPath =
+      createFilename(OutputDirPath, "scan-diags.dia");
+
+  // Create imported module Swift interface files
+  ASSERT_FALSE(emitFileWithContents(SwiftDirPath, "A.swiftinterface",
+                                    "// swift-interface-format-version: 1.0\n\
+// swift-module-flags: -module-name A\n\
+import Swift\n\
+#error(\"This is an error\")\n\
+public func funcA() { }\n"));
+
+  // Paths to shims and stdlib
+  llvm::SmallString<128> ShimsLibDir = StdLibDir;
+  llvm::sys::path::append(ShimsLibDir, "shims");
+  auto Target = llvm::Triple(llvm::sys::getDefaultTargetTriple());
+  llvm::sys::path::append(StdLibDir, getPlatformNameForTriple(Target));
+
+  // Generate command line
+  std::vector<std::string> CommandStr = {
+      TestPathStr,
+      std::string("-I ") + SwiftDirPath,
+      std::string("-I ") + StdLibDir.str().str(),
+      std::string("-I ") + ShimsLibDir.str().str(),
+      "-serialize-diagnostics-path",
+      SerializedDiagnosticsOutputPath,
+      "-module-name",
+      "testSerializedDiagnosticOutput"};
+  // On Windows we need to add an extra escape for path separator characters
+  // because otherwise the command line tokenizer will treat them as escape
+  // characters.
+  for (size_t i = 0; i < CommandStr.size(); ++i) {
+    std::replace(CommandStr[i].begin(), CommandStr[i].end(), '\\', '/');
+  }
+  std::vector<const char *> Command;
+  for (auto &command : CommandStr)
+    Command.push_back(command.c_str());
+
+  {
+    auto ScanningService = std::make_unique<SwiftDependencyScanningService>();
+    std::vector<DepScanInMemoryDiagnosticCollector::ScannerDiagnosticInfo>
+        InitializationDiagnostics;
+    auto QueryContext = ScannerTool.createScanQueryContext(Command, {},
+                                                           InitializationDiagnostics);
+    ASSERT_FALSE(QueryContext.getError());
+
+    ModuleDependenciesCache ScanCache(
+        QueryContext->ScanInstance.get()->getMainModule()->getNameStr().str(),
+        QueryContext->ScanInstance.get()
+            ->getInvocation()
+            .getModuleScanningHash());
+    auto DependenciesOrErr =
+        performModuleScan(*ScanningService, ScanCache, *QueryContext);
+
+    ASSERT_FALSE(DependenciesOrErr.getError());
+  }
+  ASSERT_TRUE(llvm::sys::fs::exists(SerializedDiagnosticsOutputPath));
+
+  auto DiagnosticsReader = DiagnosticChecker();
+  auto ReadError = DiagnosticsReader.readDiagnostics(SerializedDiagnosticsOutputPath);
+  ASSERT_FALSE(ReadError);
+  ASSERT_TRUE(DiagnosticsReader.errorMessages.size() == 1);
+  ASSERT_TRUE(DiagnosticsReader.warningMessages.size() == 1);
+  ASSERT_TRUE(DiagnosticsReader.errorMessages.front() == "This is an error");
+  ASSERT_TRUE(DiagnosticsReader.warningMessages.front() == "This is a warning");
 }
 
 TEST_F(ScanTest, TestModuleCycle) {
@@ -307,9 +422,7 @@ public func funcB() { }\n"));
   for (auto &command : CommandStr)
     Command.push_back(command.c_str());
 
-  auto ScanDiagnosticConsumer = std::make_shared<DependencyScanDiagnosticCollector>();
-
-  auto DependenciesOrErr = ScannerTool.getDependencies(Command, {}, {});
+  auto DependenciesOrErr = ScannerTool.getDependencies(Command, {});
 
   // Ensure a hollow output with diagnostic info is produced
   ASSERT_FALSE(DependenciesOrErr.getError());
@@ -329,3 +442,78 @@ public func funcB() { }\n"));
   ASSERT_TRUE(Dependencies->dependencies->modules[0]->link_libraries->count == 0);
   swiftscan_dependency_graph_dispose(Dependencies);
 }
+
+TEST_F(ScanTest, TestStressConcurrentDiagnostics) {
+  SmallString<256> tempDir;
+  ASSERT_FALSE(llvm::sys::fs::createUniqueDirectory("ScanTest.TestStressConcurrentDiagnostics", tempDir));
+  SWIFT_DEFER { llvm::sys::fs::remove_directories(tempDir); };
+
+  // Create includes
+  std::string IncludeDirPath = createFilename(tempDir, "include");
+  ASSERT_FALSE(llvm::sys::fs::create_directory(IncludeDirPath));
+  std::string CHeadersDirPath = createFilename(IncludeDirPath, "CHeaders");
+  ASSERT_FALSE(llvm::sys::fs::create_directory(CHeadersDirPath));
+
+  // Create test input file
+  std::string TestPathStr = createFilename(tempDir, "foo.swift");
+
+  // Create imported module C modulemap/headers
+  std::string modulemapContent = "";
+  std::string testFileContent = "";
+  for (int i = 0; i < 100; ++i) {
+    std::string headerName = "A_" + std::to_string(i) + ".h";
+    std::string headerContent = "void funcA_" + std::to_string(i) + "(void);";
+    ASSERT_FALSE(
+        emitFileWithContents(CHeadersDirPath, headerName, headerContent));
+
+    std::string moduleMapEntry = "module A_" + std::to_string(i) + "{\n";
+    moduleMapEntry.append("header \"A_" + std::to_string(i) + ".h\"\n");
+    moduleMapEntry.append("export *\n");
+    moduleMapEntry.append("}\n");
+    modulemapContent.append(moduleMapEntry);
+    testFileContent.append("import A_" + std::to_string(i) + "\n");
+  }
+
+  ASSERT_FALSE(emitFileWithContents(tempDir, "foo.swift", testFileContent));
+  ASSERT_FALSE(
+      emitFileWithContents(CHeadersDirPath, "module.modulemap", modulemapContent));
+
+  // Paths to shims and stdlib
+  llvm::SmallString<128> ShimsLibDir = StdLibDir;
+  llvm::sys::path::append(ShimsLibDir, "shims");
+  auto Target = llvm::Triple(llvm::sys::getDefaultTargetTriple());
+  llvm::sys::path::append(StdLibDir, getPlatformNameForTriple(Target));
+
+  std::vector<std::string> BaseCommandStrArr = {
+    TestPathStr,
+    std::string("-I ") + CHeadersDirPath,
+    std::string("-I ") + StdLibDir.str().str(),
+    std::string("-I ") + ShimsLibDir.str().str(),
+    // Pass in a flag which will cause every instantiation of
+    // the clang scanner to fail with "unknown argument"
+    "-Xcc",
+    "-foobar"
+  };
+
+  std::vector<std::string> CommandStr = BaseCommandStrArr;
+  CommandStr.push_back("-module-name");
+  CommandStr.push_back("testConcurrentDiags");
+
+  // On Windows we need to add an extra escape for path separator characters because otherwise
+  // the command line tokenizer will treat them as escape characters.
+  for (size_t i = 0; i < CommandStr.size(); ++i) {
+    std::replace(CommandStr[i].begin(), CommandStr[i].end(), '\\', '/');
+  }
+  std::vector<const char*> Command;
+  for (auto &command : CommandStr)
+    Command.push_back(command.c_str());
+
+  auto DependenciesOrErr = ScannerTool.getDependencies(Command, {});
+
+  // Ensure a hollow output with diagnostic info is produced
+  ASSERT_FALSE(DependenciesOrErr.getError());
+  auto Dependencies = DependenciesOrErr.get();
+  auto Diagnostics = Dependencies->diagnostics;
+  ASSERT_TRUE(Diagnostics->count > 100);
+  swiftscan_dependency_graph_dispose(Dependencies);
+}
diff --git a/unittests/DependencyScan/PrintTarget.cpp b/unittests/DependencyScan/PrintTarget.cpp
index e0366ed5d83eb..6b0edd6ccacd0 100644
--- a/unittests/DependencyScan/PrintTarget.cpp
+++ b/unittests/DependencyScan/PrintTarget.cpp
@@ -52,7 +52,7 @@ TEST_F(ScanTest, TestTargetInfoQuery) {
 
   auto targetInfoStr = std::string(swift::c_string_utils::get_C_string(targetInfo.get()));
   EXPECT_NE(targetInfoStr.find("\"triple\": \"x86_64-apple-macosx12.0\""), std::string::npos);
-  EXPECT_NE(targetInfoStr.find("\"librariesRequireRPath\": false"), std::string::npos);
+  EXPECT_NE(targetInfoStr.find("\"librariesRequireRPath\": true"), std::string::npos);
 
   std::string expectedRuntimeResourcePath = "\"runtimeResourcePath\": \"" + relativeLibPath.str().str() + "\"";
   // On windows, need to normalize the path back to "\\" separators
diff --git a/unittests/Frontend/FeatureParsingTest.cpp b/unittests/Frontend/FeatureParsingTest.cpp
index 5f60ed59a97a4..4859a55064d4e 100644
--- a/unittests/Frontend/FeatureParsingTest.cpp
+++ b/unittests/Frontend/FeatureParsingTest.cpp
@@ -20,9 +20,8 @@ FeatureParsingTest::FeatureParsingTest() : ArgParsingTest() {
   this->langMode = defaultLangMode;
 }
 
-FeatureWrapper::FeatureWrapper(Feature id)
-    : id(id), name(getFeatureName(id).data()) {
-  auto langMode = getFeatureLanguageVersion(id);
+FeatureWrapper::FeatureWrapper(Feature id) : id(id), name(id.getName().data()) {
+  auto langMode = id.getLanguageVersion();
   if (langMode) {
     this->langMode = std::to_string(*langMode);
   }
@@ -52,8 +51,8 @@ void swift::PrintTo(const LangOptions::FeatureState::Kind &value,
   case LangOptions::FeatureState::Kind::Off:
     *os << "Off";
     break;
-  case LangOptions::FeatureState::Kind::EnabledForAdoption:
-    *os << "EnabledForAdoption";
+  case LangOptions::FeatureState::Kind::EnabledForMigration:
+    *os << "EnabledForMigration";
     break;
   case LangOptions::FeatureState::Kind::Enabled:
     *os << "Enabled";
diff --git a/unittests/Frontend/IsFeatureEnabledTests.cpp b/unittests/Frontend/IsFeatureEnabledTests.cpp
index 36be02c261f34..6727e8c455a90 100644
--- a/unittests/Frontend/IsFeatureEnabledTests.cpp
+++ b/unittests/Frontend/IsFeatureEnabledTests.cpp
@@ -36,29 +36,29 @@ class IsFeatureEnabledTest
 TEST_F(IsFeatureEnabledTest, VerifyTestedFeatures) {
   auto feature = baselineF;
   {
-    ASSERT_FALSE(getUpcomingFeature(feature.name));
-    ASSERT_FALSE(getExperimentalFeature(feature.name));
-    ASSERT_FALSE(isFeatureAdoptable(feature));
+    ASSERT_FALSE(Feature::getUpcomingFeature(feature.name));
+    ASSERT_FALSE(Feature::getExperimentalFeature(feature.name));
+    ASSERT_FALSE(feature.id.isMigratable());
   }
 
   feature = upcomingF;
   {
-    ASSERT_TRUE(getUpcomingFeature(feature.name));
-    ASSERT_FALSE(isFeatureAdoptable(feature));
+    ASSERT_TRUE(Feature::getUpcomingFeature(feature.name));
+    ASSERT_FALSE(feature.id.isMigratable());
     ASSERT_LT(defaultLangMode, feature.langMode);
   }
 
   feature = adoptableUpcomingF;
   {
-    ASSERT_TRUE(getUpcomingFeature(feature.name));
-    ASSERT_TRUE(isFeatureAdoptable(feature));
+    ASSERT_TRUE(Feature::getUpcomingFeature(feature.name));
+    ASSERT_TRUE(feature.id.isMigratable());
     ASSERT_LT(defaultLangMode, feature.langMode);
   }
 
   feature = strictConcurrencyF;
   {
-    ASSERT_TRUE(getUpcomingFeature(feature.name));
-    ASSERT_FALSE(isFeatureAdoptable(feature));
+    ASSERT_TRUE(Feature::getUpcomingFeature(feature.name));
+    ASSERT_FALSE(feature.id.isMigratable());
     ASSERT_LT(defaultLangMode, feature.langMode);
   }
 
@@ -66,9 +66,9 @@ TEST_F(IsFeatureEnabledTest, VerifyTestedFeatures) {
   {
     // If these tests start failing because `experimentalF` was promoted, swap
     // it for another experimental feature one that is available in production.
-    ASSERT_TRUE(isFeatureAvailableInProduction(feature));
-    ASSERT_TRUE(getExperimentalFeature(feature.name));
-    ASSERT_FALSE(isFeatureAdoptable(feature));
+    ASSERT_TRUE(feature.id.isAvailableInProduction());
+    ASSERT_TRUE(Feature::getExperimentalFeature(feature.name));
+    ASSERT_FALSE(feature.id.isMigratable());
   }
 }
 
@@ -81,7 +81,7 @@ TEST_P(IsFeatureEnabledTest, ) {
     auto actualState = getLangOptions().getFeatureState(feature);
     auto expectedState = pair.second;
     ASSERT_EQ(actualState, expectedState)
-        << "Feature: " + getFeatureName(feature).str();
+        << "Feature: " + feature.getName().str();
   }
 }
 
@@ -119,7 +119,7 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-upcoming-feature", baselineF.name + ":undef"},
       {{baselineF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase(
-      {"-enable-upcoming-feature", baselineF.name + ":adoption"},
+      {"-enable-upcoming-feature", baselineF.name + ":migrate"},
       {{baselineF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase(
       {"-enable-experimental-feature", baselineF.name},
@@ -128,7 +128,7 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-experimental-feature", baselineF.name + ":undef"},
       {{baselineF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase(
-      {"-enable-experimental-feature", baselineF.name + ":adoption"},
+      {"-enable-experimental-feature", baselineF.name + ":migrate"},
       {{baselineF, FeatureState::Enabled}}),
 
   IsFeatureEnabledTestCase(
@@ -138,7 +138,7 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-upcoming-feature", upcomingF.name + ":undef"},
       {{upcomingF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
-      {"-enable-upcoming-feature", upcomingF.name + ":adoption"},
+      {"-enable-upcoming-feature", upcomingF.name + ":migrate"},
       {{upcomingF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
       {"-enable-experimental-feature", upcomingF.name},
@@ -147,7 +147,7 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-experimental-feature", upcomingF.name + ":undef"},
       {{upcomingF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
-      {"-enable-experimental-feature", upcomingF.name + ":adoption"},
+      {"-enable-experimental-feature", upcomingF.name + ":migrate"},
       {{upcomingF, FeatureState::Off}}),
 
   IsFeatureEnabledTestCase(
@@ -157,14 +157,14 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-upcoming-feature", adoptableUpcomingF.name + ":undef"},
       {{adoptableUpcomingF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
-      {"-enable-upcoming-feature", adoptableUpcomingF.name + ":adoption"},
-      {{adoptableUpcomingF, FeatureState::EnabledForAdoption}}),
+      {"-enable-upcoming-feature", adoptableUpcomingF.name + ":migrate"},
+      {{adoptableUpcomingF, FeatureState::EnabledForMigration}}),
 // Swift 7 is asserts-only.
 #ifndef NDEBUG
-  // Requesting adoption mode in target language mode has no effect.
+  // Requesting migration mode in target language mode has no effect.
   IsFeatureEnabledTestCase({
         "-swift-version", adoptableUpcomingF.langMode,
-        "-enable-upcoming-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-upcoming-feature", adoptableUpcomingF.name + ":migrate",
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
 #endif
@@ -175,14 +175,14 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-experimental-feature", adoptableUpcomingF.name + ":undef"},
       {{adoptableUpcomingF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
-      {"-enable-experimental-feature", adoptableUpcomingF.name + ":adoption"},
-      {{adoptableUpcomingF, FeatureState::EnabledForAdoption}}),
+      {"-enable-experimental-feature", adoptableUpcomingF.name + ":migrate"},
+      {{adoptableUpcomingF, FeatureState::EnabledForMigration}}),
 // Swift 7 is asserts-only.
 #ifndef NDEBUG
-  // Requesting adoption mode in target language mode has no effect.
+  // Requesting migration mode in target language mode has no effect.
   IsFeatureEnabledTestCase({
         "-swift-version", adoptableUpcomingF.langMode,
-        "-enable-experimental-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-experimental-feature", adoptableUpcomingF.name + ":migrate",
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
 #endif
@@ -193,7 +193,7 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-upcoming-feature", strictConcurrencyF.name + ":undef"},
       {{strictConcurrencyF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
-      {"-enable-upcoming-feature", strictConcurrencyF.name + ":adoption"},
+      {"-enable-upcoming-feature", strictConcurrencyF.name + ":migrate"},
       {{strictConcurrencyF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
       {"-enable-experimental-feature", strictConcurrencyF.name},
@@ -202,7 +202,7 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-experimental-feature", strictConcurrencyF.name + ":undef"},
       {{strictConcurrencyF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
-      {"-enable-experimental-feature", strictConcurrencyF.name + ":adoption"},
+      {"-enable-experimental-feature", strictConcurrencyF.name + ":migrate"},
       {{strictConcurrencyF, FeatureState::Off}}),
 
   IsFeatureEnabledTestCase(
@@ -212,7 +212,7 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-upcoming-feature", experimentalF.name + ":undef"},
       {{experimentalF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
-      {"-enable-upcoming-feature", experimentalF.name + ":adoption"},
+      {"-enable-upcoming-feature", experimentalF.name + ":migrate"},
       {{experimentalF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
       {"-enable-experimental-feature", experimentalF.name},
@@ -221,7 +221,7 @@ static const IsFeatureEnabledTestCase singleEnableTestCases[] = {
       {"-enable-experimental-feature", experimentalF.name + ":undef"},
       {{experimentalF, FeatureState::Off}}),
   IsFeatureEnabledTestCase(
-      {"-enable-experimental-feature", experimentalF.name + ":adoption"},
+      {"-enable-experimental-feature", experimentalF.name + ":migrate"},
       {{experimentalF, FeatureState::Off}}),
 };
 // clang-format on
@@ -300,7 +300,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
-        "-enable-upcoming-feature", upcomingF.name + ":adoption",
+        "-enable-upcoming-feature", upcomingF.name + ":migrate",
         "-enable-upcoming-feature", upcomingF.name,
       },
       {{upcomingF, FeatureState::Enabled}}),
@@ -311,7 +311,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-upcoming-feature", upcomingF.name,
-        "-enable-upcoming-feature", upcomingF.name + ":adoption",
+        "-enable-upcoming-feature", upcomingF.name + ":migrate",
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
@@ -320,7 +320,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
-        "-enable-upcoming-feature", upcomingF.name + ":adoption",
+        "-enable-upcoming-feature", upcomingF.name + ":migrate",
         "-enable-experimental-feature", upcomingF.name,
       },
       {{upcomingF, FeatureState::Enabled}}),
@@ -331,7 +331,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-upcoming-feature", upcomingF.name,
-        "-enable-experimental-feature", upcomingF.name + ":adoption",
+        "-enable-experimental-feature", upcomingF.name + ":migrate",
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
@@ -340,7 +340,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
-        "-enable-experimental-feature", upcomingF.name + ":adoption",
+        "-enable-experimental-feature", upcomingF.name + ":migrate",
         "-enable-upcoming-feature", upcomingF.name,
       },
       {{upcomingF, FeatureState::Enabled}}),
@@ -351,7 +351,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", upcomingF.name,
-        "-enable-upcoming-feature", upcomingF.name + ":adoption",
+        "-enable-upcoming-feature", upcomingF.name + ":migrate",
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
@@ -360,7 +360,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
-        "-enable-experimental-feature", upcomingF.name + ":adoption",
+        "-enable-experimental-feature", upcomingF.name + ":migrate",
         "-enable-experimental-feature", upcomingF.name,
       },
       {{upcomingF, FeatureState::Enabled}}),
@@ -371,7 +371,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", upcomingF.name,
-        "-enable-experimental-feature", upcomingF.name + ":adoption",
+        "-enable-experimental-feature", upcomingF.name + ":migrate",
       },
       {{upcomingF, FeatureState::Enabled}}),
 
@@ -383,7 +383,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
-        "-enable-upcoming-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-upcoming-feature", adoptableUpcomingF.name + ":migrate",
         "-enable-upcoming-feature", adoptableUpcomingF.name,
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
@@ -394,16 +394,16 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       {{adoptableUpcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-upcoming-feature", adoptableUpcomingF.name,
-        "-enable-upcoming-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-upcoming-feature", adoptableUpcomingF.name + ":migrate",
       },
-      {{adoptableUpcomingF, FeatureState::EnabledForAdoption}}),
+      {{adoptableUpcomingF, FeatureState::EnabledForMigration}}),
   IsFeatureEnabledTestCase({
         "-enable-upcoming-feature", adoptableUpcomingF.name + ":undef",
         "-enable-experimental-feature", adoptableUpcomingF.name,
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
-        "-enable-upcoming-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-upcoming-feature", adoptableUpcomingF.name + ":migrate",
         "-enable-experimental-feature", adoptableUpcomingF.name,
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
@@ -414,16 +414,16 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       {{adoptableUpcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-upcoming-feature", adoptableUpcomingF.name,
-        "-enable-experimental-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-experimental-feature", adoptableUpcomingF.name + ":migrate",
       },
-      {{adoptableUpcomingF, FeatureState::EnabledForAdoption}}),
+      {{adoptableUpcomingF, FeatureState::EnabledForMigration}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", adoptableUpcomingF.name + ":undef",
         "-enable-upcoming-feature", adoptableUpcomingF.name,
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
-        "-enable-experimental-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-experimental-feature", adoptableUpcomingF.name + ":migrate",
         "-enable-upcoming-feature", adoptableUpcomingF.name,
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
@@ -434,16 +434,16 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       {{adoptableUpcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", adoptableUpcomingF.name,
-        "-enable-upcoming-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-upcoming-feature", adoptableUpcomingF.name + ":migrate",
       },
-      {{adoptableUpcomingF, FeatureState::EnabledForAdoption}}),
+      {{adoptableUpcomingF, FeatureState::EnabledForMigration}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", adoptableUpcomingF.name + ":undef",
         "-enable-experimental-feature", adoptableUpcomingF.name,
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
-        "-enable-experimental-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-experimental-feature", adoptableUpcomingF.name + ":migrate",
         "-enable-experimental-feature", adoptableUpcomingF.name,
       },
       {{adoptableUpcomingF, FeatureState::Enabled}}),
@@ -454,9 +454,9 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       {{adoptableUpcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", adoptableUpcomingF.name,
-        "-enable-experimental-feature", adoptableUpcomingF.name + ":adoption",
+        "-enable-experimental-feature", adoptableUpcomingF.name + ":migrate",
       },
-      {{adoptableUpcomingF, FeatureState::EnabledForAdoption}}),
+      {{adoptableUpcomingF, FeatureState::EnabledForMigration}}),
 
   // MARK: Experimental
 
@@ -466,7 +466,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       },
       {{experimentalF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
-        "-enable-experimental-feature", experimentalF.name + ":adoption",
+        "-enable-experimental-feature", experimentalF.name + ":migrate",
         "-enable-experimental-feature", experimentalF.name,
       },
       {{experimentalF, FeatureState::Enabled}}),
@@ -477,7 +477,7 @@ static const IsFeatureEnabledTestCase doubleEnableTestCases[] = {
       {{experimentalF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", experimentalF.name,
-        "-enable-experimental-feature", experimentalF.name + ":adoption",
+        "-enable-experimental-feature", experimentalF.name + ":migrate",
       },
       {{experimentalF, FeatureState::Enabled}}),
 };
@@ -501,7 +501,7 @@ static const IsFeatureEnabledTestCase enableDisableTestCases[] = {
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-upcoming-feature", upcomingF.name,
-        "-disable-upcoming-feature", upcomingF.name + ":adoption",
+        "-disable-upcoming-feature", upcomingF.name + ":migrate",
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
@@ -521,7 +521,7 @@ static const IsFeatureEnabledTestCase enableDisableTestCases[] = {
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", upcomingF.name,
-        "-disable-upcoming-feature", upcomingF.name + ":adoption",
+        "-disable-upcoming-feature", upcomingF.name + ":migrate",
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
@@ -541,7 +541,7 @@ static const IsFeatureEnabledTestCase enableDisableTestCases[] = {
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-upcoming-feature", upcomingF.name,
-        "-disable-experimental-feature", upcomingF.name + ":adoption",
+        "-disable-experimental-feature", upcomingF.name + ":migrate",
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
@@ -561,7 +561,7 @@ static const IsFeatureEnabledTestCase enableDisableTestCases[] = {
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", upcomingF.name,
-        "-disable-experimental-feature", upcomingF.name + ":adoption",
+        "-disable-experimental-feature", upcomingF.name + ":migrate",
       },
       {{upcomingF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
@@ -581,7 +581,7 @@ static const IsFeatureEnabledTestCase enableDisableTestCases[] = {
       {{experimentalF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
         "-enable-experimental-feature", experimentalF.name,
-        "-disable-experimental-feature", experimentalF.name + ":adoption",
+        "-disable-experimental-feature", experimentalF.name + ":migrate",
       },
       {{experimentalF, FeatureState::Enabled}}),
   IsFeatureEnabledTestCase({
diff --git a/unittests/Frontend/StrictConcurrencyTests.cpp b/unittests/Frontend/StrictConcurrencyTests.cpp
index 3e911291883af..8d0368c9e659f 100644
--- a/unittests/Frontend/StrictConcurrencyTests.cpp
+++ b/unittests/Frontend/StrictConcurrencyTests.cpp
@@ -42,13 +42,13 @@ static const StrictConcurrencyTestCase strictConcurrencyTestCases[] = {
       {"-enable-upcoming-feature", strictConcurrencyF.name},
       StrictConcurrency::Complete),
   StrictConcurrencyTestCase(
-      {"-enable-upcoming-feature", strictConcurrencyF.name + ":adoption"},
+      {"-enable-upcoming-feature", strictConcurrencyF.name + ":migrate"},
       StrictConcurrency::Minimal),
   StrictConcurrencyTestCase(
       {"-enable-experimental-feature", strictConcurrencyF.name},
       StrictConcurrency::Complete),
   StrictConcurrencyTestCase(
-      {"-enable-experimental-feature", strictConcurrencyF.name + ":adoption"},
+      {"-enable-experimental-feature", strictConcurrencyF.name + ":migrate"},
       StrictConcurrency::Minimal),
   StrictConcurrencyTestCase(
       {"-disable-upcoming-feature", strictConcurrencyF.name},
@@ -73,7 +73,7 @@ static const StrictConcurrencyTestCase strictConcurrencyTestCases[] = {
       StrictConcurrency::Targeted),
   StrictConcurrencyTestCase({
         "-enable-upcoming-feature",
-        strictConcurrencyF.name + "=targeted:adoption",
+        strictConcurrencyF.name + "=targeted:migrate",
       },
       StrictConcurrency::Minimal),
   StrictConcurrencyTestCase(
@@ -81,7 +81,7 @@ static const StrictConcurrencyTestCase strictConcurrencyTestCases[] = {
       StrictConcurrency::Targeted),
   StrictConcurrencyTestCase({
         "-enable-experimental-feature",
-        strictConcurrencyF.name + "=targeted:adoption",
+        strictConcurrencyF.name + "=targeted:migrate",
       },
       StrictConcurrency::Minimal),
   StrictConcurrencyTestCase(
diff --git a/unittests/FrontendTool/ModuleLoadingTests.cpp b/unittests/FrontendTool/ModuleLoadingTests.cpp
index 8dd785f3dbeb0..6b4c90f956a36 100644
--- a/unittests/FrontendTool/ModuleLoadingTests.cpp
+++ b/unittests/FrontendTool/ModuleLoadingTests.cpp
@@ -111,8 +111,7 @@ class ModuleInterfaceLoaderTest : public testing::Test {
 
     ctx->addModuleInterfaceChecker(
       std::make_unique<ModuleInterfaceCheckerImpl>(*ctx, cacheDir,
-        prebuiltCacheDir, ModuleInterfaceLoaderOptions(),
-        swift::RequireOSSAModules_t(silOpts)));
+        prebuiltCacheDir, ModuleInterfaceLoaderOptions()));
 
     auto loader = ModuleInterfaceLoader::create(
         *ctx, *static_cast<ModuleInterfaceCheckerImpl*>(
@@ -131,7 +130,7 @@ class ModuleInterfaceLoaderTest : public testing::Test {
         SerializedModuleBaseName(tempDir, SerializedModuleBaseName("Library")),
         /*ModuleInterfacePath=*/nullptr, /*ModuleInterfaceSourcePath=*/nullptr,
         &moduleBuffer, &moduleDocBuffer, &moduleSourceInfoBuffer,
-        /*skipBuildingInterface*/ false, /*IsFramework*/false);
+        /*isCanImportLookup*/ false, /*IsFramework*/false);
     ASSERT_FALSE(error);
     ASSERT_FALSE(diags.hadAnyError());
 
@@ -152,7 +151,7 @@ class ModuleInterfaceLoaderTest : public testing::Test {
 
     auto bufData = (*bufOrErr)->getBuffer();
     auto validationInfo = serialization::validateSerializedAST(
-        bufData, silOpts.EnableOSSAModules,
+        bufData,
         /*requiredSDK*/StringRef());
     ASSERT_EQ(serialization::Status::Valid, validationInfo.status);
     ASSERT_EQ(bufData, moduleBuffer->getBuffer());
diff --git a/unittests/SILOptimizer/PartitionUtilsTest.cpp b/unittests/SILOptimizer/PartitionUtilsTest.cpp
index 9247017ef66d7..4057aa9822e57 100644
--- a/unittests/SILOptimizer/PartitionUtilsTest.cpp
+++ b/unittests/SILOptimizer/PartitionUtilsTest.cpp
@@ -90,7 +90,7 @@ struct MockedPartitionOpEvaluatorWithFailureCallback final
                                      operandToStateMap),
         failureCallback(failureCallback) {}
 
-  void handleError(PartitionOpError error) {
+  void handleError(PartitionOpError &&error) {
     switch (error.getKind()) {
     case PartitionOpError::UnknownCodePattern:
     case PartitionOpError::SentNeverSendable:
@@ -98,9 +98,10 @@ struct MockedPartitionOpEvaluatorWithFailureCallback final
     case PartitionOpError::InOutSendingNotInitializedAtExit:
     case PartitionOpError::InOutSendingNotDisconnectedAtExit:
     case PartitionOpError::NonSendableIsolationCrossingResult:
+    case PartitionOpError::InOutSendingReturned:
       llvm_unreachable("Unsupported");
     case PartitionOpError::LocalUseAfterSend: {
-      auto state = error.getLocalUseAfterSendError();
+      auto state = std::move(error).getLocalUseAfterSendError();
       failureCallback(*state.op, state.sentElement, state.sendingOp);
     }
     }
diff --git a/unittests/Sema/BindingInferenceTests.cpp b/unittests/Sema/BindingInferenceTests.cpp
index 34f29ad2730d7..fdd6c6682a489 100644
--- a/unittests/Sema/BindingInferenceTests.cpp
+++ b/unittests/Sema/BindingInferenceTests.cpp
@@ -22,10 +22,7 @@ using namespace swift::constraints;
 using namespace swift::constraints::inference;
 
 TEST_F(SemaTest, TestIntLiteralBindingInference) {
-  ConstraintSystemOptions options;
-  options |= ConstraintSystemFlags::AllowUnresolvedTypeVariables;
-
-  ConstraintSystem cs(DC, options);
+  ConstraintSystem cs(DC, std::nullopt);
 
   auto *intLiteral = IntegerLiteralExpr::createFromUnsigned(Context, 42, SourceLoc());
 
diff --git a/unittests/Sema/ConstraintGenerationTests.cpp b/unittests/Sema/ConstraintGenerationTests.cpp
index 7d4717869395e..e6b36257ae4d5 100644
--- a/unittests/Sema/ConstraintGenerationTests.cpp
+++ b/unittests/Sema/ConstraintGenerationTests.cpp
@@ -286,10 +286,8 @@ TEST_F(SemaTest, TestSwitchExprLocator) {
       {IntegerLiteralExpr::createFromUnsigned(Context, 1, SourceLoc())});
   auto *truePattern = ExprPattern::createImplicit(
       Context, new (Context) BooleanLiteralExpr(true, SourceLoc()), DC);
-  auto *trueCase =
-      CaseStmt::create(Context, CaseParentKind::Switch, SourceLoc(),
-                       {CaseLabelItem(truePattern)}, SourceLoc(), SourceLoc(),
-                       trueBrace, /*caseBodyVars*/ std::nullopt);
+  auto *trueCase = CaseStmt::createImplicit(
+      Context, CaseParentKind::Switch, {CaseLabelItem(truePattern)}, trueBrace);
 
   // case false: 2
   auto *falseBrace = BraceStmt::createImplicit(
@@ -298,9 +296,8 @@ TEST_F(SemaTest, TestSwitchExprLocator) {
   auto *falsePattern = ExprPattern::createImplicit(
       Context, new (Context) BooleanLiteralExpr(false, SourceLoc()), DC);
   auto *falseCase =
-      CaseStmt::create(Context, CaseParentKind::Switch, SourceLoc(),
-                       {CaseLabelItem(falsePattern)}, SourceLoc(), SourceLoc(),
-                       falseBrace, /*caseBodyVars*/ std::nullopt);
+      CaseStmt::createImplicit(Context, CaseParentKind::Switch,
+                               {CaseLabelItem(falsePattern)}, falseBrace);
 
   auto *subject = new (Context) BooleanLiteralExpr(true, SourceLoc());
 
diff --git a/unittests/Sema/PlaceholderTypeInferenceTests.cpp b/unittests/Sema/PlaceholderTypeInferenceTests.cpp
index 62e4a4d1982b7..c43c4d2a6929e 100644
--- a/unittests/Sema/PlaceholderTypeInferenceTests.cpp
+++ b/unittests/Sema/PlaceholderTypeInferenceTests.cpp
@@ -49,7 +49,7 @@ TEST_F(SemaTest, TestPlaceholderInferenceForArrayLiteral) {
 
   auto &solution = solutions[0];
 
-  auto eltTy = solution.simplifyType(solution.getType(arrayExpr))->isArrayType();
+  auto eltTy = solution.simplifyType(solution.getType(arrayExpr))->getArrayElementType();
   ASSERT_TRUE(eltTy);
   ASSERT_TRUE(eltTy->is<StructType>());
   ASSERT_EQ(eltTy->getAs<StructType>()->getDecl(), intTypeDecl);
diff --git a/unittests/SourceKit/SwiftLang/CloseTest.cpp b/unittests/SourceKit/SwiftLang/CloseTest.cpp
index e2d989f467208..5ad62c86d9533 100644
--- a/unittests/SourceKit/SwiftLang/CloseTest.cpp
+++ b/unittests/SourceKit/SwiftLang/CloseTest.cpp
@@ -82,8 +82,8 @@ class CloseTest : public ::testing::Test {
     INITIALIZE_LLVM();
     Ctx = std::make_shared<SourceKit::Context>(
         getSwiftExecutablePath(), getRuntimeLibPath(),
-        /*diagnosticDocumentationPath*/ "", SourceKit::createSwiftLangSupport,
-        [](SourceKit::Context &Ctx){ return nullptr; },
+        SourceKit::createSwiftLangSupport,
+        [](SourceKit::Context &Ctx) { return nullptr; },
         /*dispatchOnMain=*/false);
   }
 
diff --git a/unittests/SourceKit/SwiftLang/CursorInfoTest.cpp b/unittests/SourceKit/SwiftLang/CursorInfoTest.cpp
index ac30a1f1b8f6a..a5560bb24f296 100644
--- a/unittests/SourceKit/SwiftLang/CursorInfoTest.cpp
+++ b/unittests/SourceKit/SwiftLang/CursorInfoTest.cpp
@@ -68,12 +68,11 @@ class CursorInfoTest : public ::testing::Test {
   }
 
   CursorInfoTest()
-      : Ctx(*new SourceKit::Context(getSwiftExecutablePath(),
-                                    getRuntimeLibPath(),
-                                    /*diagnosticDocumentationPath*/ "",
-                                    SourceKit::createSwiftLangSupport,
-                                    [](SourceKit::Context &Ctx){ return nullptr; },
-                                    /*dispatchOnMain=*/false)) {
+      : Ctx(*new SourceKit::Context(
+            getSwiftExecutablePath(), getRuntimeLibPath(),
+            SourceKit::createSwiftLangSupport,
+            [](SourceKit::Context &Ctx) { return nullptr; },
+            /*dispatchOnMain=*/false)) {
     INITIALIZE_LLVM();
     // This is avoiding destroying \p SourceKit::Context because another
     // thread may be active trying to use it to post notifications.
diff --git a/unittests/SourceKit/SwiftLang/EditingTest.cpp b/unittests/SourceKit/SwiftLang/EditingTest.cpp
index e5f6cd9e9a90b..7650e946fdbe9 100644
--- a/unittests/SourceKit/SwiftLang/EditingTest.cpp
+++ b/unittests/SourceKit/SwiftLang/EditingTest.cpp
@@ -129,12 +129,11 @@ class EditTest : public ::testing::Test {
     // This is avoiding destroying \p SourceKit::Context because another
     // thread may be active trying to use it to post notifications.
     // FIXME: Use shared_ptr ownership to avoid such issues.
-    Ctx = new SourceKit::Context(getSwiftExecutablePath(),
-                                 getRuntimeLibPath(),
-                                 /*diagnosticDocumentationPath*/ "",
-                                 SourceKit::createSwiftLangSupport,
-                                 [](SourceKit::Context &Ctx){ return nullptr; },
-                                 /*dispatchOnMain=*/false);
+    Ctx = new SourceKit::Context(
+        getSwiftExecutablePath(), getRuntimeLibPath(),
+        SourceKit::createSwiftLangSupport,
+        [](SourceKit::Context &Ctx) { return nullptr; },
+        /*dispatchOnMain=*/false);
     auto localDocUpdState = std::make_shared<DocUpdateMutexState>();
     Ctx->getNotificationCenter()->addDocumentUpdateNotificationReceiver(
         [localDocUpdState](StringRef docName) {
diff --git a/unittests/runtime/CMakeLists.txt b/unittests/runtime/CMakeLists.txt
index 0d16c104c916a..9c972edac4832 100644
--- a/unittests/runtime/CMakeLists.txt
+++ b/unittests/runtime/CMakeLists.txt
@@ -140,6 +140,18 @@ if(("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "${SWIFT_PRIMARY_VARIANT_SDK}") AND
   target_include_directories(SwiftRuntimeTests BEFORE PRIVATE
     ${SWIFT_SOURCE_DIR}/stdlib/public)
 
+  # `stdlib/include/llvm/Support` headers, a subset of
+  # `llvm-project/llvm/include/llvm/Support`, are not compatible with the
+  # latter.
+  #
+  # Since we favor stdlib headers here, this makes sure Support headers will not
+  # be transitively included through gtest, and helps to avoid mixed includes,
+  # where a Support header existing only in LLVM is picked from LLVM, whereas
+  # a Support header existing in both of the aforementioned directories is
+  # picked from our stdlib.
+  target_compile_definitions(SwiftRuntimeTests PRIVATE
+    GTEST_NO_LLVM_SUPPORT)
+
   # FIXME: cross-compile for all variants.
   target_link_libraries(SwiftRuntimeTests
     PRIVATE
diff --git a/unittests/runtime/CompatibilityOverrideConcurrency.cpp b/unittests/runtime/CompatibilityOverrideConcurrency.cpp
index b2fa56b6e0b05..bd146a11644db 100644
--- a/unittests/runtime/CompatibilityOverrideConcurrency.cpp
+++ b/unittests/runtime/CompatibilityOverrideConcurrency.cpp
@@ -92,11 +92,11 @@ swift_task_checkIsolated_override(SerialExecutorRef executor,
 }
 
 SWIFT_CC(swift)
-static bool
+static int8_t
 swift_task_isIsolatingCurrentContext_override(SerialExecutorRef executor,
                                       swift_task_isIsolatingCurrentContext_original original) {
   Ran = true;
-  return true;
+  return 0;
 }
 
 SWIFT_CC(swift)
@@ -118,7 +118,7 @@ static void swift_task_startOnMainActor_override(AsyncTask* task) {
 }
 
 SWIFT_CC(swift)
-static void swift_task_startSynchronously_override(AsyncTask* task) {
+static void swift_task_immediate_override(AsyncTask* task, SerialExecutorRef targetExecutor) {
   Ran = true;
 }
 
@@ -350,8 +350,8 @@ TEST_F(CompatibilityOverrideConcurrencyTest, test_swift_startOnMainActorImpl) {
   swift_task_startOnMainActor(nullptr);
 }
 
-TEST_F(CompatibilityOverrideConcurrencyTest, test_swift_startSynchronously) {
-  swift_task_startSynchronously(nullptr);
+TEST_F(CompatibilityOverrideConcurrencyTest, test_swift_immediately) {
+  swift_task_immediate(nullptr, SerialExecutorRef::generic());
 }
 
 TEST_F(CompatibilityOverrideConcurrencyTest,
diff --git a/unittests/runtime/CompatibilityOverrideRuntime.cpp b/unittests/runtime/CompatibilityOverrideRuntime.cpp
index 63a7cb5110d02..46e4ed0c54a83 100644
--- a/unittests/runtime/CompatibilityOverrideRuntime.cpp
+++ b/unittests/runtime/CompatibilityOverrideRuntime.cpp
@@ -12,7 +12,7 @@
 
 #if defined(__APPLE__) && defined(__MACH__)
 
-#define SWIFT_TARGET_LIBRARY_NAME swiftRuntime
+#define SWIFT_TARGET_LIBRARY_NAME swiftRuntimeCore
 
 #include "../../stdlib/public/CompatibilityOverride/CompatibilityOverride.h"
 #include "swift/Runtime/Casting.h"
@@ -55,14 +55,14 @@ namespace  {
 
 struct OverrideSection {
   uintptr_t version;
-  
+
 #define OVERRIDE(name, ret, attrs, ccAttrs, namespace, typedArgs, namedArgs) \
   Override_ ## name name;
 #include "../../stdlib/public/CompatibilityOverride/CompatibilityOverrideRuntime.def"
 };
 
 OverrideSection RuntimeOverrides
-    __attribute__((section("__DATA," COMPATIBILITY_OVERRIDE_SECTION_NAME_swiftRuntime))) = {
+    __attribute__((section("__DATA," COMPATIBILITY_OVERRIDE_SECTION_NAME_swiftRuntimeCore))) = {
         0,
 #define OVERRIDE(name, ret, attrs, ccAttrs, namespace, typedArgs, namedArgs) \
   name ## Override,
diff --git a/userdocs/diagnostics/.gitignore b/userdocs/diagnostics/.gitignore
new file mode 100644
index 0000000000000..a61335fba2bd1
--- /dev/null
+++ b/userdocs/diagnostics/.gitignore
@@ -0,0 +1 @@
+.docc-build
\ No newline at end of file
diff --git a/userdocs/diagnostics/actor-isolated-call.md b/userdocs/diagnostics/actor-isolated-call.md
index 4c84cd4624b9f..aed3d3ceb27fc 100644
--- a/userdocs/diagnostics/actor-isolated-call.md
+++ b/userdocs/diagnostics/actor-isolated-call.md
@@ -1,5 +1,7 @@
 # Calling an actor-isolated method from a synchronous nonisolated context
 
+Accessing actor-isolated state from outside the actor can cause data races in your program. Resolve this error by calling actor-isolated functions on the actor.
+
 Calls to actor-isolated methods from outside the actor must be done asynchronously. Otherwise, access to actor state can happen concurrently and lead to data races. These rules also apply to global actors like the main actor.
 
 For example:
diff --git a/userdocs/diagnostics/always-available-domain.md b/userdocs/diagnostics/always-available-domain.md
new file mode 100644
index 0000000000000..03ee851a517b3
--- /dev/null
+++ b/userdocs/diagnostics/always-available-domain.md
@@ -0,0 +1,16 @@
+# Always enabled availability domains (AlwaysAvailableDomain)
+
+Warnings that identify `@available` attributes and `if #available` statements that reference custom availability domains which have been permanently enabled.
+
+## Overview
+
+Custom availability domains (which are an experimental feature gated by `-enable-experimental-feature CustomAvailability`) may be declared as "permanently enabled" which indicates that the domain is known available at compile time and can never become unavailable in a different configuration. This state is useful for representing feature flags for features which have become permanently enabled.
+
+Restricting a region of code to only being available in a permanently enabled availability domain will result in diagnostics that suggest the removal of the restriction. For example:
+
+```
+@available(MyFeature) // warning: '@available' has no effect because 'PermanentlyEnabled' is always available
+struct MyFeatureView: View {
+  // ...
+}
+```
diff --git a/userdocs/diagnostics/async-caller-execution.md b/userdocs/diagnostics/async-caller-execution.md
deleted file mode 100644
index 58e6f5fef2965..0000000000000
--- a/userdocs/diagnostics/async-caller-execution.md
+++ /dev/null
@@ -1,14 +0,0 @@
-# `AsyncCallerExecution`
-
-Proposed in [SE-0461], this feature changes the behavior of nonisolated async
-functions to run on the actor to which the caller is isolated (if any) by 
-default, and provides an explicit way to express the execution semantics for
-these functions:
-* The `@execution(concurrent)` attribute specifies that a function must always 
-  switch off of an actor to run.
-  This is the default behavior without `AsyncCallerExecution`.
-* The `@execution(caller)` attribute specifies that a function must always 
-  run on the caller's actor.
-  This is the default behavior with `AsyncCallerExecution`.
-
-[SE-0461]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0461-async-function-isolation.md
diff --git a/userdocs/diagnostics/availability-unrecognized-name.md b/userdocs/diagnostics/availability-unrecognized-name.md
new file mode 100644
index 0000000000000..1caf5bb107c11
--- /dev/null
+++ b/userdocs/diagnostics/availability-unrecognized-name.md
@@ -0,0 +1,18 @@
+# Unrecognized availability platforms (AvailabilityUnrecognizedName)
+
+Warnings that identify unrecognized platform names in `@available` attributes and `if #available` statements.
+
+## Overview
+
+The `AvailabilityUnrecognizedName` group covers warnings emitted when the platform name specified in an availability related construct is unrecognized by the compiler:
+
+```
+@available(NotAValidPlatform, introduced: 1.0) // warning: unrecognized platform name 'NotAValidPlatform'
+public func function() {
+  if #available(NotAValidPlatform 2.0, *) { // warning: unrecognized platform name 'NotAValidPlatform'
+    // ...
+  }
+}
+```
+
+Availability specifications with unrecognized platform names in `@available` attributes and `#available` queries are ignored by the compiler.
diff --git a/userdocs/diagnostics/clang-declaration-import.md b/userdocs/diagnostics/clang-declaration-import.md
new file mode 100644
index 0000000000000..cf5775aae7668
--- /dev/null
+++ b/userdocs/diagnostics/clang-declaration-import.md
@@ -0,0 +1,19 @@
+# Imported Clang declaration warnings (ClangDeclarationImport)
+
+Covers all warnings related to malformed APIs that are imported into Swift from C, C++, and Obj-C headers.
+
+
+## Overview
+
+As one example of a potential malformed API diagnostic, suppose a Clang module dependency contained the following declaration:
+
+```
+typedef int NotificationIdentifier
+    __attribute__((swift_name("Notification.Identifier")))
+```
+
+The Swift compiler would emit the following warning if no type named `Notification` could be found:
+
+```
+warning: imported declaration 'NotificationIdentifier' could not be mapped to 'Notification.Identifier’
+```
diff --git a/userdocs/diagnostics/compilation-caching.md b/userdocs/diagnostics/compilation-caching.md
new file mode 100644
index 0000000000000..e00b9f651c3e6
--- /dev/null
+++ b/userdocs/diagnostics/compilation-caching.md
@@ -0,0 +1,21 @@
+# Compilation caching (CompilationCaching)
+
+Errors and warnings related to the compiler's CAS compilation caching.
+
+
+## Overview
+
+Compilation caching allows Swift compiler to reuse previously compiled outputs if the identical
+compilation has been done before.
+
+When compilation caching is enabled (via `-cache-compile-job` flag), the build commands are
+expected to be generated by Swift driver, and the command-line of compilation tasks contains
+CASIDs that are objects constructed during planning phase. These CAS objects need to be backed
+by CAS storage and in a specific scheme accepted by the compiler. Any malformed command-line
+will cause error in this category. If the inputs changed, always fallback to re-run `swiftc`
+command to plan the new build commands.
+
+The other category of error is unexpected failures when performing reads/writes to Content
+Addressable Storage. Please refer to the error message (contains errors provided by CAS storage) for clues.
+If the error persists, consider clearing the cache. To clear the cache, delete the directory
+pointed to by the `-cas-path` option. Note that the CAS directory should only be deleted as a whole when not used.
diff --git a/userdocs/diagnostics/conformance-isolation.md b/userdocs/diagnostics/conformance-isolation.md
index 6d4b0adfd66df..a2db04fb953e9 100644
--- a/userdocs/diagnostics/conformance-isolation.md
+++ b/userdocs/diagnostics/conformance-isolation.md
@@ -1,5 +1,7 @@
 # Protocol conformances crossing into actor-isolated code
 
+Protocol conformances crossing into actor-isolated code can cause data races in your program. Resolve this error by ensuring access to isolated state is always done within the actor.
+
 When a type conforms to a protocol, any generic code can perform operations on that type through the protocol. If the operations that the type used to satisfy the protocol requirements are actor-isolated, this may result in a diagnostic indicating that the conformance crosses into actor-isolated code. For example:
 
 ```swift
diff --git a/userdocs/diagnostics/deprecated-declaration.md b/userdocs/diagnostics/deprecated-declaration.md
index 12e557f3f15fe..cc80590bbde06 100644
--- a/userdocs/diagnostics/deprecated-declaration.md
+++ b/userdocs/diagnostics/deprecated-declaration.md
@@ -1,7 +1,8 @@
-# Deprecated Declaration Warnings (`DeprecatedDeclaration`)
+# Deprecated declaration warnings (DeprecatedDeclaration)
 
+Warnings related to deprecated APIs that may be removed in future versions and should be replaced with more current alternatives.
 
-This diagnostic group includes warnings related to deprecated APIs that may be removed in future versions and should be replaced with more current alternatives.
+## Overview
 
 The `DeprecatedDeclaration` group covers the following warnings:
 - Use of a function annotated with `@available(<platform>, deprecated: <version>)`
@@ -65,10 +66,3 @@ The `DeprecatedDeclaration` group covers the following warnings:
     func enqueue(_ job: __owned Job) {} // 'Executor.enqueue(Job)' is deprecated as a protocol requirement; conform type 'C' to 'Executor' by implementing 'func enqueue(ExecutorJob)' instead
   }
   ```
-
-## Usage Example
-
-```sh
-swiftc -Werror DeprecatedDeclaration file.swift
-swiftc -warnings-as-errors -Wwarning DeprecatedDeclaration file.swift
-```
diff --git a/userdocs/diagnostics/diagnostic-descriptions.md b/userdocs/diagnostics/diagnostic-descriptions.md
new file mode 100644
index 0000000000000..5f20bec345374
--- /dev/null
+++ b/userdocs/diagnostics/diagnostic-descriptions.md
@@ -0,0 +1,42 @@
+# Diagnostic descriptions
+
+<!-- This file is auto-generated via `swift swift/utils/generate-doc-index.swift` -->
+
+Detailed explanations for various compiler diagnostics.
+
+
+## Overview
+
+Swift diagnostics are classified into errors and warnings. Warnings can only be silenced in an
+intentional manner, e.g., adding `_ =` for an unused function result.
+
+Some diagnostics have more detailed explanations available. These include a `[#Name]` inline and
+reference to this documentation at the end of the compiler output on the command line, or is
+presented specially within your IDE of choice. See below for the full list of these notes.
+
+
+## Topics
+
+- <doc:dynamic-callable-requirements>
+- <doc:trailing-closure-matching>
+- <doc:actor-isolated-call>
+- <doc:sendable-closure-captures>
+- <doc:string-interpolation-conformance>
+- <doc:isolated-conformances>
+- <doc:error-in-future-swift-version>
+- <doc:module-not-testable>
+- <doc:multiple-inheritance>
+- <doc:nominal-types>
+- <doc:property-wrapper-requirements>
+- <doc:protocol-type-non-conformance>
+- <doc:exclusivity-violation>
+- <doc:conformance-isolation>
+- <doc:result-builder-methods>
+- <doc:sendable-metatypes>
+- <doc:sending-closure-risks-data-race>
+- <doc:sending-risks-data-race>
+- <doc:temporary-pointers>
+- <doc:opaque-type-inference>
+- <doc:mutable-global-variable>
+- <doc:existential-member-access-limitations>
+- <doc:performance-hints>
diff --git a/userdocs/diagnostics/diagnostic-groups.md b/userdocs/diagnostics/diagnostic-groups.md
new file mode 100644
index 0000000000000..609e732c154d5
--- /dev/null
+++ b/userdocs/diagnostics/diagnostic-groups.md
@@ -0,0 +1,41 @@
+# Diagnostic groups
+
+<!-- This file is auto-generated via `swift swift/utils/generate-doc-index.swift` -->
+
+Diagnostic groups allow controlling the behavior of warnings in a more precise manner.
+
+
+## Overview
+
+Diagnostic groups collect some number of diagnostics together under a common group name. This allows
+for extra documentation to help explain relevant language concepts, as well as the ability to
+control the behavior of warnings in a more precise manner:
+- `-Werror <group>` - upgrades warnings in the specified group to errors
+- `-Wwarning <group>` - indicates that warnings in the specified group should remain warnings, even
+  if they were previously upgraded to errors
+
+As a concrete example, to upgrade deprecated declaration warnings to errors:
+```sh
+-Werror DeprecatedDeclaration
+```
+
+Or upgrade all warnings except deprecated declaration to errors:
+```sh
+-warnings-as-errors -Wwarning DeprecatedDeclaration
+```
+
+
+## Topics
+
+- <doc:compilation-caching>
+- <doc:deprecated-declaration>
+- <doc:implementation-only-deprecated>
+- <doc:embedded-restrictions>
+- <doc:preconcurrency-import>
+- <doc:clang-declaration-import>
+- <doc:missing-module-on-known-paths>
+- <doc:module-version-missing>
+- <doc:strict-language-features>
+- <doc:strict-memory-safety>
+- <doc:unknown-warning-group>
+- <doc:availability-unrecognized-name>
diff --git a/userdocs/diagnostics/diagnostics.md b/userdocs/diagnostics/diagnostics.md
new file mode 100644
index 0000000000000..0f0af419265d4
--- /dev/null
+++ b/userdocs/diagnostics/diagnostics.md
@@ -0,0 +1,14 @@
+# Swift compiler diagnostics
+
+@Metadata {
+   @TechnologyRoot
+}
+
+Documentation on diagnostics emitted by the compiler and settings that control them.
+
+
+## Topics
+
+- <doc:diagnostic-descriptions>
+- <doc:diagnostic-groups>
+- <doc:upcoming-language-features>
diff --git a/userdocs/diagnostics/embedded-restrictions.md b/userdocs/diagnostics/embedded-restrictions.md
new file mode 100644
index 0000000000000..ed10ccea7d00c
--- /dev/null
+++ b/userdocs/diagnostics/embedded-restrictions.md
@@ -0,0 +1,58 @@
+# Embedded Swift language restrictions (EmbeddedRestrictions)
+
+Embedded Swift is a subset of the Swift language that that introduces some restrictions on the use of language features to eliminate the need for the Swift runtime. These restrictions are captured by the `EmbeddedRestrictions` diagnostic group.
+
+The Embedded Swift compilation model can produce extremely small binaries without external dependencies, suitable for restricted environments including embedded (microcontrollers) and baremetal setups (no operating system at all), and low-level environments (firmware, kernels, device drivers, low-level components of userspace OS runtimes). While the vast majority of Swift language features are available in Embedded Swift, there are some language features that require the full Swift standard library and runtime, which are not available in Embedded Swift.
+
+Diagnostics in the `EmbeddedRestrictions` group describe those language features that cannot be used in Embedded Swift. These include:
+
+* `weak` and `unowned` references, because Embedded Swift uses a simplified reference-counting model that cannot support them. For example:
+
+      class Node {
+        weak var parent: Node?    // error: attribute 'weak' cannot be used in Embedded Swift
+      }
+
+* Dynamic casts to a type involving a protocol are not supported, because Embedded Swift does not include runtime metadata about protocol conformances. For example:
+
+      protocol P: AnyObject { }
+      func casting(object: AnyObject) {
+        if let p = object as? P { // error: cannot perform a dynamic cast to a type involving protocol 'P' in Embedded Swift
+          // ...
+        }
+      }
+
+* Non-final generic methods in a class, which are prohibited because they cannot be specialized for every possible call site. For example:
+
+      class MyGenericClass<T> {
+        func f<U>(value: U) { } // warning: generic instance method 'f(value:)' in a class must be 'final' in Embedded Swift
+
+        func g() { } // okay, not generic relative to the class itself
+
+        class func h() where T: P { } // warning: generic class method 'h()' in a class must be 'final' in Embedded Swift
+      }
+
+* Generic methods used on values of protocol type, which are prohibited because they cannot be specialized for every possible call site. For example:
+
+      protocol P: AnyObject {
+        func doNothing()
+        func doSomething<T>(on value: T)
+      }
+
+      func testGenerics<Value: P>(value: value, i: Int) {
+        value.doNothing()        // okay
+        value.doSomething(on: i) // okay, always specialized
+      }
+
+      func testValuesOfProtocolType(value: any P, i: Int) {
+        value.doNothing()        // okay
+        value.doSomething(on: i) // warning: cannot use generic instance method 'doSomething(on:)' on a value of type 'any P' in Embedded Swift
+      }
+
+* Use of untyped throws, which depends on `any Error` and is not available in Embedded Swift. Use typed throws instead:
+
+      func mayFail() throws { } // error: untyped throws is not available in Embedded Swift; add a thrown error type with '(type)'
+      func mayFail() throws(MyError) // okay
+
+## See Also
+
+- [A Vision for Embedded Swift](https://github.com/swiftlang/swift-evolution/blob/main/visions/embedded-swift.md)
diff --git a/userdocs/diagnostics/error-in-future-swift-version.md b/userdocs/diagnostics/error-in-future-swift-version.md
index ea82a3da56303..c10ca6e9807dc 100644
--- a/userdocs/diagnostics/error-in-future-swift-version.md
+++ b/userdocs/diagnostics/error-in-future-swift-version.md
@@ -1,5 +1,7 @@
 # Language mode and tools version
 
+Swift language mode and Swift compiler tools version are distinct concepts. One compiler version can support multiple language modes.
+
 There are two related kinds of "Swift version" that are distinct:
 
 * Swift tools version: the version number of the compiler itself. For example, the Swift 5.6 compiler was introduced in March 2022.
diff --git a/userdocs/diagnostics/exclusivity-violation.md b/userdocs/diagnostics/exclusivity-violation.md
new file mode 100644
index 0000000000000..6c01fc1839ecd
--- /dev/null
+++ b/userdocs/diagnostics/exclusivity-violation.md
@@ -0,0 +1,61 @@
+# Overlapping accesses, but operation requires exclusive access
+
+Swift requires exclusive access to a variable in order to modify that variable. An error is reported if a program attempts to access a variable while it is already in the process of being accessed via another name. These issues can often be resolved by making a local copy of a variable before modifying it.
+
+In the following example, `count` is accessed for modification by passing it as an `inout` argument to `modifyTwice`. This `inout` access to `count` lasts for the entire duration of the `modifyTwice` function call. The exclusivity violation occurs because the `modifier` closure also accesses `count` via the name `$0` while the first access is in progress.
+
+```swift
+func modifyTwice(_ value: inout Int, by modifier: (inout Int) -> ()) {
+  modifier(&value)
+  modifier(&value)
+}
+
+func testCount() {
+  var count = 1
+  modifyTwice(&count) { $0 += count } // error: overlapping accesses to 'count', but modification requires exclusive access; consider copying to a local variable
+  print(count)
+}
+```
+
+This exclusivity violation can be fixed by introducing a local variable to track the value the `modifier` closure should add to its argument.
+
+```swift
+func modifyTwice(_ value: inout Int, by modifier: (inout Int) -> ()) {
+  modifier(&value)
+  modifier(&value)
+}
+
+func testCount() {
+  var count = 1
+  let incrementBy = count
+  modifyTwice(&count) { $0 += incrementBy }
+  print(count)
+}
+```
+
+In this updated program, `count` and `$0` no longer refer to the same variable, so accessing them at the same time does not violate exclusivity.
+
+Another common source of exclusivity violations occurs when a `mutating` method modifies `self`:
+
+```swift
+extension Array {
+    mutating func append(removingFrom other: inout Array<Element>) {
+        while !other.isEmpty {
+            self.append(other.removeLast())
+        }
+    }
+}
+
+var numbers = [1, 2, 3]
+numbers.append(removingFrom: &numbers) // error: overlapping accesses to 'x', but modification requires exclusive access; consider copying to a local variable
+```
+
+A `mutating` method accesses `self` for the duration of the method call, so in this example `numbers` has two conflicting long-lived accesses, one as `self` and one as an `inout` argument to the method. Again, a local variable can be introduced to eliminate the conflict:
+
+```swift
+var numbers = [1, 2, 3]
+var toAppend = numbers
+numbers.append(removingFrom: &toAppend)
+```
+
+Exclusivity checks play an important role in enforcing memory safety and enabling compiler optimizations. To learn more, see [Swift 5 Exclusivity Enforcement](https://www.swift.org/blog/swift-5-exclusivity/) on the Swift.org blog.
\ No newline at end of file
diff --git a/userdocs/diagnostics/existential-any.md b/userdocs/diagnostics/existential-any.md
index b1a1b9cb2da3d..62f12f77e7830 100644
--- a/userdocs/diagnostics/existential-any.md
+++ b/userdocs/diagnostics/existential-any.md
@@ -1,24 +1,47 @@
-# `ExistentialAny`
+# Existential any (ExistentialAny)
 
-This diagnostic group includes errors and warnings pertaining to the `any` type
-syntax proposed in [SE-0335].
-`any` syntax draws a line between constraint types and existential or boxed
-types.
+`any` existential type syntax.
 
-For example, `any Collection` is a boxed type abstracting over a value of a
-dynamic type that conforms to the protocol `Collection`, whereas the
-`Collection` part is the conformance constraint imposed on the type of the
-underlying value *as well as* a constraint type.
-The distinction between a conformance constraint and a constraint type can be
-clearly seen in classic generic syntax: `<T: Collection>`.
 
-Constraint types exist to express conformances and have no meaning in relation
-to values.
+## Overview
 
+`any` was introduced in Swift 5.6 to explicitly mark "existential types", i.e., abstract boxed types
+that conform to a set of constraints. For source compatibility, these are not diagnosed by default
+except for existential types constrained to protocols with `Self` or associated type requirements
+(as this was introduced in the same version):
 ```swift
-func sillyFunction(collection: Collection) { // error
-  // ...
+protocol Foo {
+  associatedtype Bar
+
+  func foo(_: Bar)
 }
+
+protocol Baz {}
+
+func pass(foo: Foo) {} // `any Foo` is required instead of `Foo`
+
+func pass(baz: Baz) {} // no warning or error by default for source compatibility
 ```
 
-[SE-0335]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0335-existential-any.md
+When enabled via `-enable-upcoming-feature ExistentialAny`, the upcoming language feature
+`ExistentialAny` will diagnose *all* existential types without `any`:
+```swift
+func pass(baz: Baz) {} // `any Baz` required instead of `Baz`
+```
+
+This will become the default in a future language mode.
+
+
+## Migration
+
+```sh
+-enable-upcoming-feature ExistentialAny:migrate
+```
+
+Enabling migration for `ExistentialAny` adds fix-its that prepend all existential types with `any`
+as required. No attempt is made to convert to generic (`some`) types.
+
+
+## See Also
+
+- [SE-0335: Introduce existential `any`](https://github.com/swiftlang/swift-evolution/blob/main/proposals/0335-existential-any.md)
diff --git a/userdocs/diagnostics/implementation-only-deprecated.md b/userdocs/diagnostics/implementation-only-deprecated.md
new file mode 100644
index 0000000000000..d93c65c771f1e
--- /dev/null
+++ b/userdocs/diagnostics/implementation-only-deprecated.md
@@ -0,0 +1,23 @@
+# Deprecated implementation-only imports (ImplementationOnlyDeprecated)
+
+Warnings that identify `import` declarations with the `@_implementationOnly` attribute.
+
+## Overview
+
+When applied to `import` declarations, the compiler-internal attribute `@_implementationOnly` attempts prevents declarations from the imported module from being exposed in the ABI or public interface of the dependent module. This attribute became deprecated when support for access levels on `import` declarations was introduced with [SE-0409].
+
+One reason `@_implementationOnly import` is deprecated is that it is unsafe when used in modules that are built _without_ [library evolution] enabled. For example, suppose the following code were part of a library named `Foo`:
+
+```swift
+// Library `Foo`
+@_implementationOnly import ImplementationDetail
+
+public struct Bar {
+  internal var x: Baz // defined in ImplementationDetail
+}
+```
+
+If `Foo` is not compiled with library evolution, then the memory layout of values of `Bar` must be known at compile time in clients of `Foo`. However, the `@_implementationOnly import` of `ImplementationDetail` prevents clients from being able to look up `Baz` which is a type that contributes to the layout of `Foo`. As a result, the layout of `Foo` will be miscalculated resulting in undefined behavior.
+
+[SE-0409]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0409-access-level-on-imports.md
+[library evolution]: https://www.swift.org/blog/library-evolution/
diff --git a/userdocs/diagnostics/isolated-conformances.md b/userdocs/diagnostics/isolated-conformances.md
index 1d61753ed6eaf..f89d6360e0295 100644
--- a/userdocs/diagnostics/isolated-conformances.md
+++ b/userdocs/diagnostics/isolated-conformances.md
@@ -1,5 +1,7 @@
 # Isolated conformances
 
+Using an isolated conformance from outside the actor can cause data races in your program. Resolve these errors by only using isolated conformances within the actor.
+
 A protocol conformance can be isolated to a specific global actor, meaning that the conformance can only be used by code running on that actor. Isolated conformances are expressed by specifying the global actor on the conformance itself:
 
 ```swift
diff --git a/userdocs/diagnostics/member-import-visibility.md b/userdocs/diagnostics/member-import-visibility.md
new file mode 100644
index 0000000000000..af9bcd35602ca
--- /dev/null
+++ b/userdocs/diagnostics/member-import-visibility.md
@@ -0,0 +1,36 @@
+# Member import visibility (MemberImportVisibility)
+
+Enables errors for uses of members that cannot be accessed because their defining module is not directly
+imported.
+
+
+## Overview
+
+Prior to enabling this feature, it was possible to use a member if it was declared in a module that
+was transitively imported. `MemberImportVisibility` unifies the visibility rules for members to
+match those of top-level, such that only members contained in a direct import are visible:
+
+```swift
+func getFileContents() throws -> String {
+  // error: initializer 'init(contentsOfFile:)' is not available due to missing import of defining module 'Foundation'
+  return try String(contentsOfFile: "example.txt")
+}
+```
+
+To resolve the error, add an import of the module that defines the member.
+
+
+## Migration
+
+```sh
+-enable-upcoming-feature MemberImportVisibility:migrate
+```
+
+Enabling migration for `MemberImportVisibility` adds fix-its for the missing modules, i.e. those that
+declare members used in the file and are not directly imported.
+
+
+## See also
+
+- [SE-0444: Member import visibility](https://github.com/swiftlang/swift-evolution/blob/main/proposals/0444-member-import-visibility.md)
+
diff --git a/userdocs/diagnostics/missing-module-on-known-paths.md b/userdocs/diagnostics/missing-module-on-known-paths.md
new file mode 100644
index 0000000000000..b284bd7262ed2
--- /dev/null
+++ b/userdocs/diagnostics/missing-module-on-known-paths.md
@@ -0,0 +1,23 @@
+# Missing module on known path from a dependency (MissingModuleOnKnownPaths)
+
+Notes related to information about a missing module dependency.
+
+
+## Overview
+
+This diagnostic group covers notes related to displaying information about a missing module dependency which the compiler is able to locate as present on a search path found in a loaded Swift binary module, but which is not specified to the current compilation.
+
+As one example of a potential missing module diagnostic, suppose an imported module `Foo` is resolved to a Swift binary module which itself depends on module `Bar` and was built with an additional search path where `Bar` is located, and suppose that the client which imports `Foo` does not specify this search path:
+
+```
+import Foo
+```
+
+The Swift compiler would emit a module-not-found error and a note to inform the user of the missing search path containing `Bar` which was found serialized in `Foo`'s binary Swift module:
+
+```
+error: Compilation search paths unable to resolve module dependency: 'Bar' [#MissingModuleOnKnownPaths]
+note: 'Bar' can be found using a search path that was specified when building module 'Foo' ('<Search Path>'). This search path was not specified on the current compilation.
+```
+
+Some prior versions of the Swift compiler erroneously inherited search paths from loaded binary Swift modules and used them to resolve other, subsequently-encountered module dependencies. All search paths required to resolve direct and transitive module dependencies must be explicitly specified on the compiler invocation which will encounter these dependencies.
diff --git a/userdocs/diagnostics/module-not-testable.md b/userdocs/diagnostics/module-not-testable.md
new file mode 100644
index 0000000000000..3e37850ec0279
--- /dev/null
+++ b/userdocs/diagnostics/module-not-testable.md
@@ -0,0 +1,5 @@
+# Module not testable
+
+Modules imported using `@testable import` must have been compiled using the `-enable-testing` compiler flag.
+
+`@testable import` allows clients of a module to access `internal` API when writing tests. A `@testable import` will report an error if the imported module was not compiled with the `-enable-testing` compiler flag. Use of `-enable-testing` is recommended only in debug builds or other builds not intended for production use.
\ No newline at end of file
diff --git a/userdocs/diagnostics/module-version-missing.md b/userdocs/diagnostics/module-version-missing.md
new file mode 100644
index 0000000000000..b05c141465618
--- /dev/null
+++ b/userdocs/diagnostics/module-version-missing.md
@@ -0,0 +1,26 @@
+# Missing module version (ModuleVersionMissing)
+
+Warnings that indicate the compiler cannot resolve an `#if canImport(<ModuleName>, _version: <version>)` directive because the module found was not built with a `-user-module-version` flag.
+
+
+## Overview
+
+Developers may conditionalize which code is active in a source file based on the module version number of an imported dependency module, like this:
+
+```swift
+import Dependency
+
+#if canImport(Dependency, _version: 1.2)
+// Use declarations introduced in version 1.2 of Dependency
+#else
+// ...
+#endif
+```
+
+A dependency's module version must be established by passing the `-user-module-version` flag when compiling the sources of the dependency the module. If no `-user-module-version` flag was specified when the dependency module was built, then the compiler will warn that it cannot resolve the `#if canImport` directive:
+
+```
+warning: cannot find user version number for module 'Dependency'; version number ignored [#ModuleVersionMissing]
+```
+
+If this diagnostic is emitted, then the `#if canImport` directive implicitly evaluates true.
diff --git a/userdocs/diagnostics/mutable-global-variable.md b/userdocs/diagnostics/mutable-global-variable.md
index 3f8b450a27475..b20fc2abd786a 100644
--- a/userdocs/diagnostics/mutable-global-variable.md
+++ b/userdocs/diagnostics/mutable-global-variable.md
@@ -1,5 +1,7 @@
 # Unsafe mutable global and static variables
 
+Mutable global and static variables that can be accessed from anywhere can cause data races in your program. Resolve this error by making the state immutable or protecting it with a global actor.
+
 Concurrency checking prohibits mutable global and static variables that are `nonisolated` because they can be accessed from arbitrary concurrency domains at once and lead to data races.
 
 For example:
diff --git a/userdocs/diagnostics/nonisolated-nonsending-by-default.md b/userdocs/diagnostics/nonisolated-nonsending-by-default.md
new file mode 100644
index 0000000000000..bf34db60108f7
--- /dev/null
+++ b/userdocs/diagnostics/nonisolated-nonsending-by-default.md
@@ -0,0 +1,74 @@
+# nonisolated(nonsending) by Default (NonisolatedNonsendingByDefault)
+
+Runs nonisolated async functions on the caller's actor by default.
+
+
+## Overview
+
+Prior to this feature, nonisolated async functions *never* run on an actor's executor and instead
+switch to global generic executor. The motivation was to prevent unnecessary serialization and
+contention for the actor by switching off of the actor to run the nonisolated async function, but
+this does  have a number of unfortunate consequences:
+1. `nonisolated` is difficult to understand
+2. Async functions that run on the caller's actor are difficult to express
+3. It's easy to write invalid async APIs
+4. It's difficult to write higher-order async APIs
+
+Introduced in Swift 6.2, `-enable-upcoming-feature NonisolatedNonsendingByDefault` changes the
+execution semantics of nonisolated async functions to always run on the caller's actor by default. A
+new `@concurrent` attribute can be added in order to specify that a function must *always* switch
+off of an actor to run.
+```swift
+struct S: Sendable {
+  func performSync() {}
+
+  // `nonisolated(nonsending)` is the default
+  func performAsync() async {}
+
+  @concurrent
+  func alwaysSwitch() async {}
+}
+
+actor MyActor {
+  let s: Sendable
+
+  func call() async {
+    s.performSync() // runs on actor's executor
+
+    await s.performAsync() // runs on actor's executor
+
+    s.alwaysSwitch() // switches to global generic executor
+  }
+}
+```
+
+A `nonisolated(nonsending)` modifier can also be used prior to enabling this upcoming feature in
+order to run on the caller's actor. To achieve the same semantics as above, `S` in this case would
+instead be:
+```swift
+struct S: Sendable {
+  func performSync() {}
+
+  nonisolated(nonsending)
+  func performAsync() async {}
+
+  // `@concurrent` is the default
+  func alwaysSwitch() async {}
+}
+```
+
+
+## Migration
+
+```sh
+-enable-upcoming-feature NonisolatedNonsendingByDefault:migrate
+```
+
+Enabling migration for `NonisolatedNonsendingByDefault` adds fix-its that aim to keep the current
+async semantics by adding `@concurrent` to all existing nonisolated async functions and closures.
+
+
+## See Also
+
+- [SE-0461: Run nonisolated async functions on the caller's actor by default](https://github.com/swiftlang/swift-evolution/blob/main/proposals/0461-async-function-isolation.md)
+
diff --git a/userdocs/diagnostics/performance-hints.md b/userdocs/diagnostics/performance-hints.md
new file mode 100644
index 0000000000000..a50f49502864a
--- /dev/null
+++ b/userdocs/diagnostics/performance-hints.md
@@ -0,0 +1,3 @@
+# Swift Performance Hint: Function returning Array or Dictionary type
+
+- TODO: Docs
diff --git a/userdocs/diagnostics/preconcurrency-import.md b/userdocs/diagnostics/preconcurrency-import.md
index c436c5f7fd8d5..308f77e48b843 100644
--- a/userdocs/diagnostics/preconcurrency-import.md
+++ b/userdocs/diagnostics/preconcurrency-import.md
@@ -1,6 +1,4 @@
-# Extraneous @preconcurrency imports
+# Extraneous @preconcurrency imports (PreconcurrencyImport)
 
-
-This diagnostic group includes warnings that diagnose `@preconcurrency import`
-declarations that don't need `@preconcurrency`. It is an experimental warning
-that is currently disabled.
\ No newline at end of file
+Warnings that diagnose `@preconcurrency import` declarations that don't need `@preconcurrency`,
+experimental and disabled by default.
diff --git a/userdocs/diagnostics/sendable-closure-captures.md b/userdocs/diagnostics/sendable-closure-captures.md
index b19f7b47e02fd..fdf9d90d95417 100644
--- a/userdocs/diagnostics/sendable-closure-captures.md
+++ b/userdocs/diagnostics/sendable-closure-captures.md
@@ -80,7 +80,7 @@ The compiler diagnoses the capture of `model` in a `@Sendable` closure:
 | func capture(model: MyModel) async {
 |   callConcurrently {
 |     model.log()
-|     `- error: capture of 'model' with non-sendable type 'MyModel' in a '@Sendable' closure
+|     `- error: capture of 'model' with non-Sendable type 'MyModel' in a '@Sendable' closure
 |   }
 | }
 ```
@@ -115,4 +115,4 @@ func capture(model: MyModel) async {
     model.log()
   }
 }
-```
\ No newline at end of file
+```
diff --git a/userdocs/diagnostics/sendable-metatypes.md b/userdocs/diagnostics/sendable-metatypes.md
new file mode 100644
index 0000000000000..eeb2321910f83
--- /dev/null
+++ b/userdocs/diagnostics/sendable-metatypes.md
@@ -0,0 +1,62 @@
+# Sendable metatypes
+
+Types that are shared in concurrent code generally need to conform to `Sendable`. The same is true in generic code when sharing parameters of a generic parameter `T`. For example, the given code will produce an error under strict concurrency checking
+
+```swift
+func doSomethingElsewhere<T>(_ value: T) {
+  Task { @concurrent in
+    print(value) // warning: capture of non-Sendable type 'T'
+  }
+}
+```
+
+because `value` can have a non-Sendable type that is not safe to share. To address this potential data race, the type `T` can be marked as `Sendable`:
+
+```swift
+func doSomethingElsewhere<T: Sendable>(_ value: T) {
+  Task { @concurrent in
+    print(value)
+  }
+}
+```
+
+The same issue can occur when passing the type `T` itself, rather than a value of type `T`. The compiler will indicate such problems by noting that the metatype of `T`, spelled `T.Type`, is not `Sendable`:
+
+```swift
+protocol P {
+  static func doSomething()
+}
+
+func doSomethingStatic<T: P>(_: T.Type) {
+  Task { @concurrent in
+    T.doSomething() // warning: capture of non-Sendable type 'T.Type' in an isolated closure
+  }
+}
+```
+
+In these cases, the type parameter should be required to conform to the `SendableMetatype` protocol, e.g.,
+
+```swift
+func doSomethingStatic<T: P & SendableMetatype>(_: T.Type) {
+  Task { @concurrent in
+    T.doSomething()
+  }
+}
+```
+
+The `SendableMetatype` requirement allows the function to share the type `T` in concurrent code. To maintain data race safety, it prevents callers from using isolated conformances in the call. For example, the following code will be rejected due to a data race:
+
+```swift
+@MainActor
+class C: @MainActor P {
+  static func doSomething() { }
+}
+
+@MainActor
+func test(c: C) {
+  doSomethingStatic(C.self) // error: main actor-isolated conformance of 'C' to 'P' cannot satisfy conformance requirement for a 'Sendable' type parameter
+}
+
+```
+
+The conformance of `C` to `P` can only be used on the main actor, so it cannot be provided to `doSomethingStatic`, which calls the conformance from a different concurrent task.
\ No newline at end of file
diff --git a/userdocs/diagnostics/sending-closure-risks-data-race.md b/userdocs/diagnostics/sending-closure-risks-data-race.md
index 233655960146d..e287bec3b7751 100644
--- a/userdocs/diagnostics/sending-closure-risks-data-race.md
+++ b/userdocs/diagnostics/sending-closure-risks-data-race.md
@@ -1,5 +1,7 @@
 # Sending closure risks causing data races
 
+Sharing mutable state between concurrent tasks can cause data races in your program. Resolve this error by only accessing mutable state in one task at a time.
+
 If a type does not conform to `Sendable`, the compiler enforces that each instance of that type is only accessed by one concurrency domain at a time. The compiler also prevents you from capturing values in closures that are sent to another concurrency domain if the value can be accessed from the original concurrency domain too.
 
 For example:
diff --git a/userdocs/diagnostics/sending-risks-data-race.md b/userdocs/diagnostics/sending-risks-data-race.md
index 2f7d65c187e53..46418ca327c8d 100644
--- a/userdocs/diagnostics/sending-risks-data-race.md
+++ b/userdocs/diagnostics/sending-risks-data-race.md
@@ -1,5 +1,7 @@
 # Sending value risks causing data races
 
+Sharing mutable state between concurrent tasks can cause data races in your program. Resolve this error by only accessing mutable state in one task at a time.
+
 If a type does not conform to `Sendable` the compiler will enforce that each instance of that type is only accessed by one concurrency domain at a time. The `sending 'x' risks causing data races` error indicates that your code can access a non-`Sendable` value from multiple concurrency domains at once.
 
 For example, if a value can be accessed from the main actor, it's invalid to send the same instance to another concurrency domain while the main actor can still access it. This mistake is common when calling an `async` function on a class from the main actor:
@@ -29,13 +31,13 @@ await person.printNameConcurrently()
 
 This happens because the `printNameConcurrently` function runs off of the main actor, and the `onMainActor` function suspends while waiting for `printNameConcurrently` to complete. While suspended, the main actor can run other tasks that still have access to `person`, which can lead to a data race.
 
-The most common fix is to change the `async` method to run on the caller's actor using the `@execution(caller)` attribute:
+The most common fix is to change the `async` method to run on the caller's actor using the `nonisolated(nonsending)` specifier:
 
 ```swift
 class Person {
   var name: String = ""
     
-  @execution(caller)
+  nonisolated(nonsending)
   func printNameConcurrently() async {
     print(name)
   }
@@ -49,4 +51,4 @@ func onMainActor(person: Person) async {
 
 This eliminates the risk of data-races because `printNameConcurrently` continues to run on the main actor, so all access to `person` is serialized.
 
-You can also enable the `AsyncCallerExecution` upcoming feature to make `@execution(caller)` the default for async functions on non-`Sendable` types.
\ No newline at end of file
+You can also enable the `NonisolatedNonsendingByDefault` upcoming feature to make `nonisolated(nonsending)` the default for async functions on non-`Sendable` types.
diff --git a/userdocs/diagnostics/strict-language-features.md b/userdocs/diagnostics/strict-language-features.md
index 64fb854c72f4f..d74b9a420ef5a 100644
--- a/userdocs/diagnostics/strict-language-features.md
+++ b/userdocs/diagnostics/strict-language-features.md
@@ -1,8 +1,13 @@
-# Strict language feature enablement
-
-By default, if an unrecognized feature name is specified with the
-`-enable-upcoming-feature` or `-enable-experimental-feature` flags, the compiler
-will ignore it without emitting a diagnostic since some projects must be
-simultaneously compatible with multiple versions of the language and toolchain.
-However, this warning group can be enabled to opt-in to detailed diagnostics
-about misspecified features.
+# Strict language feature enablement (StrictLanguageFeatures)
+
+Warnings for unrecognized feature names in `-enable-upcoming-feature` or
+`enable-experimental-feature`.
+
+
+## Overview
+
+By default, if an unrecognized feature name is specified with the `-enable-upcoming-feature` or
+`-enable-experimental-feature` flags, the compiler will ignore it without emitting a diagnostic
+since some projects must be simultaneously compatible with multiple versions of the language and
+toolchain. This can, however, lead to misspecified features. To diagnose these cases instead, enable
+`StrictLanguageFeatures`.
diff --git a/userdocs/diagnostics/strict-memory-safety.md b/userdocs/diagnostics/strict-memory-safety.md
index 0cea6dcf69588..07c7e9f5faf8a 100644
--- a/userdocs/diagnostics/strict-memory-safety.md
+++ b/userdocs/diagnostics/strict-memory-safety.md
@@ -1,7 +1,13 @@
-# Strict Memory Safety Warnings (`StrictMemorySafety`)
+# Strict memory safety (StrictMemorySafety)
 
+Warnings that identify the use of language constructs and library APIs that can undermine memory
+safety, disabled by default.
 
-This diagnostic group includes warnings that identify the use of language constructs and library APIs that can undermine memory safety. They are enabled by the `-strict-memory-safety` compiler flag. Examples of memory-unsafe code in Swift include:
+
+## Overview
+
+Strict memory safety can be enabled with the `-strict-memory-safety` compiler flag. Examples of
+memory-unsafe code in Swift include:
 
 - Use of a function or type annotated with `@unsafe`:
   ```swift
@@ -69,4 +75,4 @@ The warnings produced by strict memory safety can be suppressed by acknowledging
   @safe struct MyTemporaryBuffer<T> {
     private var storage: UnsafeBufferPointer<T>
   }
-  ```
\ No newline at end of file
+  ```
diff --git a/userdocs/diagnostics/unknown-warning-group.md b/userdocs/diagnostics/unknown-warning-group.md
index a1abba4516875..65d42150acaf3 100644
--- a/userdocs/diagnostics/unknown-warning-group.md
+++ b/userdocs/diagnostics/unknown-warning-group.md
@@ -1,6 +1,9 @@
-# Unknown "Warning Group" Warnings (`UnknownWarningGroup`)
+# Unknown warning group (UnknownWarningGroup)
 
-The `UnknownWarningGroup` diagnostic group addresses warnings related to the specification of unrecognized warning groups in compilation flags.
+Warnings for unrecognized warning groups specified in `-Wwarning` or `-Werror`.
+
+
+## Overview
 
 ```sh
 swiftc -Werror non_existing_group file.swift
diff --git a/userdocs/diagnostics/upcoming-language-features.md b/userdocs/diagnostics/upcoming-language-features.md
new file mode 100644
index 0000000000000..ec3cb9d7850ba
--- /dev/null
+++ b/userdocs/diagnostics/upcoming-language-features.md
@@ -0,0 +1,24 @@
+# Upcoming language features
+
+<!-- This file is auto-generated via `swift swift/utils/generate-doc-index.swift` -->
+
+Upcoming language features enable new (but potentially source breaking) functionality that be
+enabled by default in an upcoming language mode.
+
+
+## Overview
+
+Upcoming language features allow the incremental adoption of language features that would otherwise
+only be available in a new language mode, without having to fully migrate to that mode. They can be
+enabled on the command line with `-enable-upcoming-feature <feature>`.
+
+Some upcoming features have an additional "migration" mode, where the compiler will emit warnings
+with fix-its to help migrate to that mode. This can be enabled with `-enable-upcoming-feature
+<feature>:migrate`.
+
+
+## Topics
+
+- <doc:existential-any>
+- <doc:member-import-visibility>
+- <doc:nonisolated-nonsending-by-default>
diff --git a/utils/SwiftIntTypes.py b/utils/SwiftIntTypes.py
index fec4f489710a7..431e2f147f237 100644
--- a/utils/SwiftIntTypes.py
+++ b/utils/SwiftIntTypes.py
@@ -72,6 +72,16 @@ def all_integer_types(word_bits):
             is_word=True, bits=word_bits,
             is_signed=is_signed)
 
+def all_signed_types(word_bits):
+    for bitwidth in _all_integer_type_bitwidths:
+        yield SwiftIntegerType(
+            is_word=False, bits=bitwidth,
+            is_signed=True)
+    
+    yield SwiftIntegerType(
+        is_word=True, bits=word_bits,
+        is_signed=True)
+
 # 'truncatingBitPattern' initializer is defined if the conversion is truncating
 # on any platform that Swift supports.
 
diff --git a/utils/api_checker/swift-api-checker.py b/utils/api_checker/swift-api-checker.py
index 9ec87c088f306..c1941eb82a971 100755
--- a/utils/api_checker/swift-api-checker.py
+++ b/utils/api_checker/swift-api-checker.py
@@ -146,7 +146,7 @@ def run(self, output, module, swift_ver, opts,
                '/tmp/ModuleCache', '-swift-version',
                swift_ver, '-abort-on-module-fail']
         for path in self.frameworks:
-            cmd.extend(['-iframework', path])
+            cmd.extend(['-Fsystem', path])
         for path in self.inputs:
             cmd.extend(['-I', path])
         if self.abi:
diff --git a/utils/availability-macros.def b/utils/availability-macros.def
index 85e476f88830d..d9b51bf7c21af 100644
--- a/utils/availability-macros.def
+++ b/utils/availability-macros.def
@@ -15,6 +15,14 @@
 # Each of the remaining lines must define an availability macro in the same
 # format used by the `-define-availability` frontend command line option.
 
+# NOTE: The build system will define another macro, StdlibDeploymentTarget, for
+#       each SwiftStdlib macro defined in this file.  The difference between the
+#       two is the the StdlibDeploymentTarget macro will never be set to a
+#       higher version than the machine on which we are building.
+#
+#       This is to allow for use of new functions and types within the standard
+#       libraries, in such a way that these usages will work on our CI machines.
+
 # 9999 is the generic unknown future Swift release. It always needs to resolve
 # to the special placeholder version numbers 9999.
 
@@ -36,8 +44,16 @@ SwiftStdlib 5.8:macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4
 SwiftStdlib 5.9:macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0
 SwiftStdlib 5.10:macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.1
 SwiftStdlib 6.0:macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0
-SwiftStdlib 6.1:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999
+SwiftStdlib 6.1:macOS 15.4, iOS 18.4, watchOS 11.4, tvOS 18.4, visionOS 2.4
 SwiftStdlib 6.2:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999
+SwiftStdlib 6.3:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999
+
+# Like SwiftStdlib 5.0, but also the oldest visionOS.
+SwiftCompatibilitySpan 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2, visionOS 1.0
+
+# Identical to SwiftStdlib 6.2.
+SwiftCompatibilitySpan 6.2:macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0
+
 # TODO: When you add a new version, remember to tell the compiler about it
 # by also adding it to include/swift/AST/RuntimeVersions.def.
 
diff --git a/utils/build-presets.ini b/utils/build-presets.ini
index 7686c34e40fdb..9b852a964f77e 100644
--- a/utils/build-presets.ini
+++ b/utils/build-presets.ini
@@ -19,7 +19,7 @@ swift-install-components=back-deployment;compiler;clang-builtin-headers;libexec;
 [preset: mixin_buildbot_install_components_with_clang]
 
 swift-install-components=autolink-driver;back-deployment;compiler;clang-resource-dir-symlink;libexec;stdlib;sdk-overlay;static-mirror-lib;toolchain-tools;license;sourcekit-xpc-service;sourcekit-inproc;swift-remote-mirror;swift-remote-mirror-headers
-llvm-install-components=llvm-ar;llvm-ranlib;llvm-cov;llvm-profdata;IndexStore;clang;clang-resource-headers;compiler-rt;clangd;libclang;dsymutil;LTO;clang-features-file;lld
+llvm-install-components=llvm-ar;llvm-nm;llvm-ranlib;llvm-cov;llvm-profdata;llvm-objdump;llvm-objcopy;llvm-symbolizer;IndexStore;clang;clang-resource-headers;builtins;runtimes;clangd;libclang;dsymutil;LTO;clang-features-file;lld
 
 [preset: mixin_buildbot_trunk_base]
 # Build standard library and SDK overlay for iOS device and simulator.
@@ -424,6 +424,8 @@ mixin-preset=buildbot_incremental_base
 # on Foundation, so that is built as well. On OS X, Foundation is built as part
 # of the XCTest Xcode project.
 xctest
+swift-testing
+swift-testing-macros
 
 build-swift-stdlib-unittest-extra
 
@@ -441,6 +443,8 @@ skip-test-foundation
 release
 assertions
 xctest
+swift-testing
+swift-testing-macros
 test
 
 skip-test-cmark
@@ -625,6 +629,8 @@ swiftformat
 swift-driver
 indexstore-db
 sourcekit-lsp
+swift-testing
+swift-testing-macros
 # Failing to build in CI: rdar://78408440
 # swift-inspect
 install-llvm
@@ -635,6 +641,8 @@ install-swiftpm
 install-swiftsyntax
 install-swift-driver
 install-swiftformat
+install-swift-testing
+install-swift-testing-macros
 
 # We need to build the unittest extras so we can test
 build-swift-stdlib-unittest-extra
@@ -671,15 +679,16 @@ skip-test-llbuild
 
 enable-new-runtime-build
 
+# Escalate certain C++ warnings to errors for Swift.
+extra-swift-cmake-options=
+   -DSWIFT_EXTRA_CXX_FLAGS="-Werror=unused -Werror=uninitialized"
+
 [preset: buildbot_incremental,tools=RA,stdlib=RD,smoketest=macosx,flto]
 mixin-preset=buildbot_incremental,tools=RA,stdlib=RD,smoketest=macosx
 build-subdir=buildbot_incremental
 
 lto
 
-[preset: ncgenerics,smoketest=macosx]
-mixin-preset=buildbot_incremental,tools=RA,stdlib=RD,smoketest=macosx
-build-subdir=buildbot_incremental
 
 [preset: buildbot_incremental,tools=RA,llvm-only]
 build-subdir=buildbot_incremental_llvmonly
@@ -705,6 +714,7 @@ extra-cmake-options=
 
 # Do not build swift or cmark
 skip-build-swift
+skip-early-swift-driver
 skip-build-cmark
 
 [preset: buildbot_incremental_lldb]
@@ -836,7 +846,7 @@ no-swift-stdlib-assertions
 [preset: mixin_linux_install_components_with_clang]
 
 swift-install-components=autolink-driver;compiler;clang-resource-dir-symlink;libexec;stdlib;swift-remote-mirror;sdk-overlay;static-mirror-lib;toolchain-tools;license;sourcekit-inproc
-llvm-install-components=llvm-ar;llvm-ranlib;llvm-cov;llvm-profdata;IndexStore;clang;clang-resource-headers;compiler-rt;clangd;libclang;lld;LTO;clang-features-file
+llvm-install-components=llvm-ar;llvm-nm;llvm-ranlib;llvm-cov;llvm-profdata;llvm-objdump;llvm-objcopy;llvm-symbolizer;IndexStore;clang;clang-resource-headers;builtins;runtimes;clangd;libclang;lld;LTO;clang-features-file
 
 [preset: mixin_linux_installation]
 mixin-preset=
@@ -850,6 +860,7 @@ swift-testing-macros
 xctest
 swiftdocc
 swiftformat
+wasmkit
 
 build-ninja
 install-llvm
@@ -867,12 +878,11 @@ install-prefix=/usr
 install-sourcekit-lsp
 install-swiftformat
 install-swiftdocc
+install-wasmkit
 build-swift-static-stdlib
 build-swift-static-sdk-overlay
 build-swift-stdlib-unittest-extra
 build-embedded-stdlib-cross-compiling
-
-wasmkit
 build-wasm-stdlib
 
 # Executes the lit tests for the installable package that is created
@@ -913,6 +923,7 @@ indexstore-db
 sourcekit-lsp
 swiftdocc
 lit-args=-v --time-tests
+foundation-tests-build-type=Debug
 
 # rdar://problem/31454823
 lldb-test-swift-only
@@ -935,11 +946,17 @@ mixin-preset=
 
 skip-test-swiftdocc
 
+[preset: buildbot_linux,release_foundation_tests]
+mixin-preset=buildbot_linux
+
+foundation-tests-build-type=Release
+
 [preset: buildbot_linux_crosscompile_wasm]
 mixin-preset=buildbot_linux
 
 llvm-targets-to-build=X86;ARM;AArch64;WebAssembly
 wasmkit
+install-wasmkit
 build-wasm-stdlib
 # FIXME(katei): Test fails on a specific CI node.
 # https://github.com/apple/swift/issues/70980
@@ -950,6 +967,13 @@ mixin-preset=buildbot_linux_base
 
 no-assertions
 
+[preset: buildbot_amazon_linux_2]
+mixin-preset=buildbot_linux
+
+skip-test-sourcekit-lsp
+skip-test-lldb
+
+extra-cmake-options=-DLLDB_ENABLE_PYTHON=NO
 
 [preset: mixin_buildbot_linux,no_test]
 skip-test-cmark
@@ -1094,6 +1118,8 @@ install-swiftformat
 reconfigure
 test-optimized
 skip-test-swiftdocc
+lldb-test-swift-only
+foundation-tests-build-type=Debug
 
 # gcc version on amazon linux 2 is too old to configure and build tablegen.
 # Use the clang that we install in the path for macros
@@ -1123,6 +1149,8 @@ lldb
 foundation
 swiftpm
 swift-driver
+swift-testing
+swift-testing-macros
 xctest
 
 build-subdir=buildbot_linux
@@ -1136,6 +1164,8 @@ install-foundation
 install-swiftpm
 install-swift-driver
 install-swiftsyntax
+install-swift-testing
+install-swift-testing-macros
 install-xctest
 install-prefix=/usr
 swift-install-components=autolink-driver;compiler;clang-builtin-headers;libexec;stdlib;swift-remote-mirror;sdk-overlay;dev
@@ -1202,6 +1232,7 @@ swiftsyntax
 swiftformat
 indexstore-db
 sourcekit-lsp
+foundation-tests-build-type=Debug
 
 install-llvm
 install-static-linux-config
@@ -1321,6 +1352,86 @@ sourcekit-lsp=0
 mixin-preset=buildbot_linux
 llvm-targets-to-build=X86;ARM;AArch64;WebAssembly
 
+#===------------------------------------------------------------------------===#
+# FreeBSD Builders
+#===------------------------------------------------------------------------===#
+[preset: mixin_freebsd_package_products]
+
+static-libxml2
+foundation
+indexstore-db
+libdispatch
+llbuild
+lldb
+sourcekit-lsp
+swift-driver
+swift-testing
+swift-testing-macros
+swiftdocc
+swiftformat
+swiftpm
+xctest
+
+swift-install-components=autolink-driver;compiler;clang-resource-dir-symlink;libexec;stdlib;swift-remote-mirror;sdk-overlay;static-mirror-lib;toolchain-tools;license;sourcekit-inproc
+llvm-install-components=llvm-ar;llvm-ranlib;llvm-cov;llvm-profdata;llvm-objdump;llvm-objcopy;llvm-symbolizer;IndexStore;clang;clang-resource-headers;builtins;runtimes;clangd;libclang;lld;LTO;clang-features-file
+
+install-foundation
+install-libdispatch
+install-llbuild
+install-lldb
+install-llvm
+install-sourcekit-lsp
+install-swift
+install-swift-driver
+install-swift-testing
+install-swift-testing-macros
+install-swiftdocc
+install-swiftformat
+install-swiftpm
+install-swiftsyntax
+install-xctest
+
+install-prefix=/usr
+
+[preset: mixin_freebsd_package_test]
+
+build-swift-stdlib-unittest-extra
+
+lit-args=-v --time-test
+long-test
+stress-test
+test
+test-optimized
+validation-test
+test-installable-package
+
+lldb-test-swift-only
+skip-test-swiftdocc
+
+[preset: freebsd_package,no_test]
+mixin-preset=
+  mixin_freebsd_package_products
+
+extra-llvm-cmake-options=
+  -DLLVM_TARGETS_TO_BUILD=AArch64;X86
+
+release
+no-swift-stdlib-assertions
+
+build-swift-static-sdk-overlay
+build-swift-static-stdlib
+
+build-subdir=buildbot_freebsd
+install-destdir=%(install_destdir)s
+installable-package=%(installable_package)s
+
+reconfigure
+
+[preset: freebsd_package]
+mixin-preset=
+  freebsd_package,no_test
+  mixin_freebsd_package_test
+
 #===------------------------------------------------------------------------===#
 # OS X Package Builders
 #===------------------------------------------------------------------------===#
@@ -1345,6 +1456,7 @@ playgroundsupport
 indexstore-db
 sourcekit-lsp
 swiftdocc
+wasmkit
 
 # Build with debug info, this allows us to symbolicate crashes from
 # production builds.
@@ -1390,6 +1502,7 @@ install-playgroundsupport
 install-sourcekit-lsp
 install-swiftformat
 install-swiftdocc
+install-wasmkit
 
 install-destdir=%(install_destdir)s
 
@@ -3003,7 +3116,7 @@ darwin-toolchain-display-name-short=Swift Development Snapshot
 darwin-toolchain-display-name=Swift Development Snapshot
 darwin-toolchain-name=swift-DEVELOPMENT-SNAPSHOT
 darwin-toolchain-version=3.999.999
-llvm-install-components=clang;clang-resource-headers;compiler-rt;libclang;libclang-headers;dsymutil;clang-features-file
+llvm-install-components=clang;clang-resource-headers;builtins;runtimes;libclang;libclang-headers;dsymutil;clang-features-file
 swift-install-components=back-deployment;compiler;clang-builtin-headers;stdlib;libexec;sdk-overlay;license;sourcekit-xpc-service;sourcekit-inproc;swift-remote-mirror;swift-remote-mirror-headers
 symbols-package=%(symbols_package)s
 install-symroot=%(install_symroot)s
@@ -3014,8 +3127,12 @@ build-subdir=compat_linux
 foundation
 libdispatch
 xctest
+swift-testing
+swift-testing-macros
 install-foundation
 install-libdispatch
+install-swift-testing
+install-swift-testing-macros
 install-xctest
 swift-install-components=autolink-driver;compiler;clang-builtin-headers;stdlib;libexec;swift-remote-mirror;sdk-overlay;license
 
@@ -3116,15 +3233,9 @@ llvm-cmake-options=
 # Build Requirements:
 #   - C and C++ compiler
 # Toolchain Outputs:
-#   - Swift Compiler
-#     C++ Driver
-#     No Macro Support
-#     No Swift Compiler Sources
+#   - Swift Compiler (-SwiftDriver, -macros, -SwiftSilOpts)
 # Runtime Outputs:
-#   - Swift Standard Library
-#     swiftCore
-#     OnoneSupport
-#     Concurrency
+#   - Swift Standard Library (-macros)
 [preset: bootstrap_stage0]
 mixin-preset=
   mixin_buildbot_linux,no_test
@@ -3133,21 +3244,208 @@ swift-include-tests=0
 llvm-include-tests=0
 
 release
+libdispatch
 
 skip-early-swiftsyntax
 skip-early-swift-driver
 skip-build-benchmarks
+build-swift-examples=0
 
 build-runtime-with-host-compiler=0
 build-swift-libexec=0
 build-swift-remote-mirror=0
+build-swift-static-sdk-overlay=0
+build-swift-static-stdlib=0
+enable-experimental-concurrency=1
+enable-experimental-distributed=0
+enable-experimental-observation=0
+enable-experimental-differentiable-programming=0
+
+extra-llvm-cmake-options=
+  -DLLVM_TARGETS_TO_BUILD=AArch64;X86
+
+extra-swift-cmake-options=
+  -DSWIFT_ENABLE_SWIFT_IN_SWIFT:BOOL=NO
+  -DSWIFT_INCLUDE_DOCS:BOOL=NO
+  -DSWIFT_BUILD_EXAMPLES:BOOL=OFF
+
+build-subdir=%(build_subdir)s
+install-destdir=%(install_destdir)s
 
 swift-install-components=autolink-driver;compiler;clang-resource-dir-symlink;stdlib;sdk-overlay;toolchain-tools
-llvm-install-components=llvm-ar;llvm-ranlib;clang;clang-resource-headers;compiler-rt;clang-features-file;llvm-symbolizer
+llvm-install-components=llvm-ar;llvm-ranlib;clang;clang-resource-headers;builtins;runtimes;clang-features-file;llvm-symbolizer
+
+install-llvm
+install-swift
+install-libdispatch
+
+# Build Toolchain Requirements:
+# - C/C++ compiler
+# - Swift Compiler (-SwiftDriver, -macros, -SwiftSilOpts)
+# Toolchain Outputs:
+# - Swift Compiler (-SwiftDriver, +macros, +SwiftSilOpts)
+# Runtime Outputs:
+# - Standard Library (+macros)
+# - Dispatch
+# - Foundation (+macros)
+[preset: bootstrap_stage1]
+mixin-preset=mixin_buildbot_linux,no_test
+bootstrapping=hosttools
+
+release
+foundation
+libdispatch
+
+skip-early-swift-driver
+skip-build-benchmarks
+
+enable-experimental-concurrency=1
 
 extra-cmake-options=
   -DLLVM_TARGETS_TO_BUILD=AArch64;X86
 
-swift-cmake-options=
-  -DSWIFT_ENABLE_SWIFT_IN_SWIFT:BOOL=NO
-  -DSWIFT_INCLUDE_DOCS:BOOL=NO
+swift-install-components=autolink-driver;compiler;clang-resource-dir-symlink;stdlib;sdk-overlay;toolchain-tools;license
+llvm-install-components=llvm-ar;llvm-ranlib;clang;clang-resource-headers;builtins;runtimes;clang-features-file;lld
+
+build-subdir=%(build_subdir)s
+install-destdir=%(install_destdir)s
+
+install-llvm
+install-swift
+install-foundation
+install-libdispatch
+
+[preset: bootstrap_stage2]
+mixin-preset=mixin_buildbot_linux,no_test
+bootstrapping=hosttools
+
+release
+
+skip-early-swift-driver
+
+llbuild
+xctest
+swift-testing
+swift-testing-macros
+swiftpm
+
+swift-include-tests=0
+llvm-include-tests=0
+
+
+foundation
+libdispatch
+
+skip-build-benchmarks
+skip-test-cmark
+
+build-subdir=%(build_subdir)s
+install-destdir=%(install_destdir)s
+
+swift-install-components=autolink-driver;compiler;clang-resource-dir-symlink;stdlib;sdk-overlay;toolchain-tools;license
+llvm-install-components=llvm-ar;llvm-ranlib;clang;clang-resource-headers;builtins;runtimes;clang-features-file;lld
+
+install-llvm
+install-swift
+install-foundation
+install-libdispatch
+install-llbuild
+install-swiftpm
+install-swift-testing
+install-swift-testing-macros
+install-xctest
+
+[preset: wasm_stdlib,macos]
+
+mixin-preset=mixin_buildbot_install_components_with_clang
+llbuild
+swiftpm
+swift-driver
+swiftsyntax
+skip-test-swiftpm
+swift-testing
+swift-testing-macros
+build-wasm-stdlib
+
+release
+build-ninja
+
+build-embedded-stdlib-cross-compiling
+
+# Don't build the benchmarks
+skip-build-benchmarks
+
+install-llvm
+install-swift
+install-llbuild
+install-swiftpm
+install-swift-driver
+install-swiftsyntax
+install-swift-testing
+install-swift-testing-macros
+install-wasmkit
+install-destdir=%(install_destdir)s
+#
+# Path where the compiler, the runtime and the standard libraries will be
+# installed.
+install-prefix=%(install_toolchain_dir)s/usr
+
+# Executes the lit tests for the installable package that is created
+# Assumes the swift-integration-tests repo is checked out
+
+; test-installable-package
+
+# If someone uses this for incremental builds, force reconfiguration.
+reconfigure
+
+# Path to the .tar.gz package we would create.
+installable-package=%(installable_package)s
+
+# Info.plist
+darwin-toolchain-bundle-identifier=%(darwin_toolchain_bundle_identifier)s
+darwin-toolchain-display-name=%(darwin_toolchain_display_name)s
+darwin-toolchain-display-name-short=%(darwin_toolchain_display_name_short)s
+darwin-toolchain-name=%(darwin_toolchain_xctoolchain_name)s
+darwin-toolchain-version=%(darwin_toolchain_version)s
+darwin-toolchain-alias=%(darwin_toolchain_alias)s
+darwin-toolchain-require-use-os-runtime=0
+
+build-subdir=wasm_stdlib
+
+# For local use only. This allows quickly rebuilding and testing Wasm stdlib
+# end-to-end without rebuilding the whole toolchain.
+[preset: wasm_stdlib_incremental]
+
+assertions
+swift-enable-ast-verifier=0
+no-swift-stdlib-assertions
+build-embedded-stdlib-cross-compiling
+build-wasm-stdlib
+release-debuginfo
+test
+lit-args=-v --time-tests
+skip-test-swiftdocc
+skip-test-cmark
+skip-test-lldb
+skip-test-swift
+skip-test-llbuild
+skip-test-swiftpm
+skip-test-swift-driver
+skip-test-xctest
+skip-test-foundation
+skip-test-libdispatch
+skip-test-playgroundsupport
+skip-test-indexstore-db
+skip-test-sourcekit-lsp
+skip-test-swiftformat
+skip-build-llvm
+skip-build-swift
+skip-early-swift-driver
+skip-build-cmark
+install-destdir=%(install_destdir)s
+build-subdir=wasm_stdlib_incremental
+
+[preset: wasm_stdlib_incremental,macos]
+
+mixin-preset=wasm_stdlib_incremental
+build-subdir=buildbot_osx
diff --git a/utils/build-script b/utils/build-script
index d4b2ecd6d7f3c..7895744f62eab 100755
--- a/utils/build-script
+++ b/utils/build-script
@@ -14,6 +14,7 @@ The ultimate tool for building Swift.
 """
 
 
+from argparse import Namespace
 import json
 import os
 import platform
@@ -187,7 +188,7 @@ def tar(source, destination):
 # -----------------------------------------------------------------------------
 # Argument Validation
 
-def validate_arguments(toolchain, args):
+def validate_arguments(toolchain, args: Namespace):
     if toolchain.cc is None or toolchain.cxx is None:
         fatal_error(
             "can't find clang (please install clang-3.5 or a "
diff --git a/utils/build-script-impl b/utils/build-script-impl
index b19e6a3fdbf09..3ebf7b45a4541 100755
--- a/utils/build-script-impl
+++ b/utils/build-script-impl
@@ -175,7 +175,6 @@ KNOWN_SETTINGS=(
     skip-clean-xctest                             "0"               "skip cleaning the xctest build"
 
     ## Test Options
-    llvm-include-tests                            "1"               "Set to true to generate testing targets for LLVM. Set to true by default."
     long-test                                     "0"               "set to run the long test suite"
     only-executable-test                          ""                "only run the executable variant of the swift lit tests"
     stress-test                                   "0"               "set to run the stress test suite"
@@ -216,6 +215,7 @@ KNOWN_SETTINGS=(
     swift-runtime-enable-leak-checker             "0"               "Enable leaks checking routines in the runtime"
     swift-stdlib-enable-assertions                "1"               "enable assertions in Swift"
     swift-stdlib-enable-debug-preconditions-in-release "0"          "Enable _debugPrecondition checks in the stdlib in Release configurations"
+    swift-stdlib-enable-strict-availability       "0"               "enable strict availability checking in the stdlib"
     swift-tools-enable-lto                        ""                "enable LTO compilation of Swift tools. *NOTE* This does not include the swift standard library and runtime. Must be set to one of 'thin' or 'full'"
     extra-swift-args                              ""                "Extra arguments to pass to swift modules which match regex. Assumed to be a flattened cmake list consisting of [module_regexp, args, module_regexp, args, ...]"
     report-statistics                             "0"               "set to 1 to generate compilation statistics files for swift libraries"
@@ -292,6 +292,7 @@ KNOWN_SETTINGS=(
     cross-compile-install-prefixes                ""                "semicolon-separated list of install prefixes to use for the cross-compiled hosts. The list expands, so if there are more cross-compile hosts than prefixes, unmatched hosts use the last prefix in the list"
     cross-compile-deps-path                       ""                "path for CMake to look for cross-compiled library dependencies, such as libXML2"
     cross-compile-append-host-target-to-destdir   "1"               "turns on appending the host target name of each cross-compiled toolchain to its install-destdir, to keep them separate from the natively-built toolchain"
+    cross-compile-build-swift-tools               "1"               "set to 1 to cross-compile the Swift host tools, like the Swift compiler"
     skip-merge-lipo-cross-compile-tools           ""                "set to skip running merge-lipo after installing cross-compiled host Swift tools"
     coverage-db                                   ""                "If set, coverage database to use when prioritizing testing"
     skip-local-host-install                       ""                "If we are cross-compiling multiple targets, skip an install pass locally if the hosts match"
@@ -461,7 +462,7 @@ function should_execute_host_actions_for_phase() {
 function verify_host_is_supported() {
     local host="$1"
     case ${host} in
-      freebsd-arm64             \
+      freebsd-aarch64           \
       | freebsd-x86_64          \
       | openbsd-x86_64          \
       | openbsd-aarch64         \
@@ -806,20 +807,6 @@ function set_build_options_for_host() {
     esac
 
 
-    # We don't currently support building compiler-rt for cross-compile targets.
-    # It's not clear that's useful anyway.
-    if [[ $(is_cross_tools_host "${host}") ]] ; then
-      llvm_cmake_options+=(
-          -DLLVM_TOOL_COMPILER_RT_BUILD:BOOL=FALSE
-          -DLLVM_BUILD_EXTERNAL_COMPILER_RT:BOOL=FALSE
-      )
-    else
-      llvm_cmake_options+=(
-          -DLLVM_TOOL_COMPILER_RT_BUILD:BOOL="$(false_true ${SKIP_BUILD_COMPILER_RT})"
-          -DLLVM_BUILD_EXTERNAL_COMPILER_RT:BOOL="$(false_true ${SKIP_BUILD_COMPILER_RT})"
-      )
-    fi
-
     # If we are asked to not generate test targets for LLVM and or Swift,
     # disable as many LLVM tools as we can. This improves compile time when
     # compiling with LTO.
@@ -840,6 +827,12 @@ function set_build_options_for_host() {
     # and it must be the same for both LLVM and Swift
 
     if [[ "${SWIFT_HOST_TRIPLE}" ]] ; then
+        # Adding this until we can configure these corelibs repos with a CMake
+        # toolchain file
+        SWIFT_TARGET_CMAKE_OPTIONS+=(
+            -DCMAKE_Swift_COMPILER_TARGET:STRING="${SWIFT_HOST_TRIPLE}"
+        )
+
         llvm_cmake_options+=(
             -DLLVM_HOST_TRIPLE:STRING="${SWIFT_HOST_TRIPLE}"
         )
@@ -1707,6 +1700,12 @@ for host in "${ALL_HOSTS[@]}"; do
                         "${cmake_options[@]}"
                         -DLLVM_TABLEGEN=$(build_directory "${LOCAL_HOST}" llvm)/bin/llvm-tblgen
                         -DSWIFT_INCLUDE_TEST_BINARIES:BOOL=FALSE
+                        -DSWIFT_INCLUDE_TOOLS:BOOL=$(true_false "${CROSS_COMPILE_BUILD_SWIFT_TOOLS}")
+                    )
+                else
+                    cmake_options=(
+                        "${cmake_options[@]}"
+                        -DSWIFT_INCLUDE_TOOLS:BOOL=$(true_false "${BUILD_SWIFT_TOOLS}")
                     )
                 fi
 
@@ -1752,6 +1751,7 @@ for host in "${ALL_HOSTS[@]}"; do
                     -DSWIFT_STDLIB_BUILD_TYPE:STRING="${SWIFT_STDLIB_BUILD_TYPE}"
                     -DSWIFT_STDLIB_ASSERTIONS:BOOL=$(true_false "${SWIFT_STDLIB_ENABLE_ASSERTIONS}")
                     -DSWIFT_STDLIB_ENABLE_DEBUG_PRECONDITIONS_IN_RELEASE=$(true_false "${SWIFT_STDLIB_ENABLE_DEBUG_PRECONDITIONS_IN_RELEASE}")
+                    -DSWIFT_STDLIB_ENABLE_STRICT_AVAILABILITY:BOOL=$(true_false "${SWIFT_STDLIB_ENABLE_STRICT_AVAILABILITY}")
                     -DSWIFT_ENABLE_DISPATCH:BOOL=$(true_false "${SWIFT_ENABLE_DISPATCH}")
                     -DSWIFT_IMPLICIT_CONCURRENCY_IMPORT:BOOL=$(true_false "${SWIFT_IMPLICIT_CONCURRENCY_IMPORT}")
                     -DSWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT:BOOL=$(true_false "${SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT}")
@@ -1779,7 +1779,6 @@ for host in "${ALL_HOSTS[@]}"; do
                     -DSWIFT_NATIVE_LLVM_TOOLS_PATH:STRING="${native_llvm_tools_path}"
                     -DSWIFT_NATIVE_CLANG_TOOLS_PATH:STRING="${native_clang_tools_path}"
                     -DSWIFT_NATIVE_SWIFT_TOOLS_PATH:STRING="${native_swift_tools_path}"
-                    -DSWIFT_INCLUDE_TOOLS:BOOL=$(true_false "${BUILD_SWIFT_TOOLS}")
                     -DSWIFT_BUILD_CLANG_OVERLAYS:BOOL=$(true_false "${BUILD_SWIFT_CLANG_OVERLAYS}")
                     -DSWIFT_BUILD_REMOTE_MIRROR:BOOL=$(true_false "${BUILD_SWIFT_REMOTE_MIRROR}")
                     -DSWIFT_STDLIB_SIL_DEBUGGING:BOOL=$(true_false "${BUILD_SIL_DEBUGGING_STDLIB}")
@@ -1937,6 +1936,13 @@ for host in "${ALL_HOSTS[@]}"; do
                     )
                 fi
 
+                if [ "${SWIFT_FREESTANDING_AVAILABILITY_NAME}" ] ; then
+                    cmake_options=(
+                        "${cmake_options[@]}"
+                        -DSWIFT_FREESTANDING_TRIPLE_NAME:STRING="${SWIFT_FREESTANDING_TRIPLE_NAME}"
+                    )
+                fi
+
                 if [ "${SWIFT_FREESTANDING_MODULE_NAME}" ] ; then
                     cmake_options=(
                         "${cmake_options[@]}"
@@ -2330,7 +2336,7 @@ for host in "${ALL_HOSTS[@]}"; do
                     continue
                 fi
 
-                if [[ "${BUILD_SWIFT_TOOLS}" == "0" ]]; then
+                if [[ "$(true_false ${CROSS_COMPILE_BUILD_SWIFT_TOOLS})" == "FALSE" ]]; then
                     echo "Skipping building Foundation Macros for ${host}, because the host tools are not being built"
                     continue
                 fi
@@ -2919,7 +2925,7 @@ for host in "${ALL_HOSTS[@]}"; do
                     continue
                 fi
 
-                if [[ "${BUILD_SWIFT_TOOLS}" == "0" && "${product}" == "foundation_macros" ]]; then
+                if [[ "$(true_false ${CROSS_COMPILE_BUILD_SWIFT_TOOLS})" == "FALSE" && "${product}" == "foundation_macros" ]]; then
                     echo "Skipping installing Foundation Macros for ${host}, because the host tools are not being built"
                     continue
                 fi
@@ -3122,7 +3128,6 @@ function build_and_test_installable_package() {
           DARWIN_TOOLCHAIN_INFO_PLIST="${host_install_destdir}${TOOLCHAIN_PREFIX}/Info.plist"
           DARWIN_TOOLCHAIN_REPORT_URL="https://bugs.swift.org/"
           COMPATIBILITY_VERSION=2
-          COMPATIBILITY_VERSION_DISPLAY_STRING="Xcode 8.0"
           DARWIN_TOOLCHAIN_CREATED_DATE="$(date -u +'%a %b %d %T GMT %Y')"
           TOOLCHAIN_PLUGIN_PATH_DESCRIPTOR='$(TOOLCHAIN_DIR)/usr/lib/swift/host/plugins'
 
@@ -3138,7 +3143,6 @@ function build_and_test_installable_package() {
           call ${PLISTBUDDY_BIN} -c "Add ShortDisplayName string '${DARWIN_TOOLCHAIN_DISPLAY_NAME_SHORT}'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
           call ${PLISTBUDDY_BIN} -c "Add CreatedDate date '${DARWIN_TOOLCHAIN_CREATED_DATE}'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
           call ${PLISTBUDDY_BIN} -c "Add CompatibilityVersion integer ${COMPATIBILITY_VERSION}" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
-          call ${PLISTBUDDY_BIN} -c "Add CompatibilityVersionDisplayString string ${COMPATIBILITY_VERSION_DISPLAY_STRING}" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
           call ${PLISTBUDDY_BIN} -c "Add Version string '${DARWIN_TOOLCHAIN_VERSION}'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
           call ${PLISTBUDDY_BIN} -c "Add CFBundleIdentifier string '${DARWIN_TOOLCHAIN_BUNDLE_IDENTIFIER}'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
           call ${PLISTBUDDY_BIN} -c "Add ReportProblemURL string '${DARWIN_TOOLCHAIN_REPORT_URL}'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
@@ -3154,9 +3158,6 @@ function build_and_test_installable_package() {
           unset IFS
 
           call ${PLISTBUDDY_BIN} -c "Add OverrideBuildSettings dict" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
-          call ${PLISTBUDDY_BIN} -c "Add OverrideBuildSettings:ENABLE_BITCODE string 'NO'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
-          call ${PLISTBUDDY_BIN} -c "Add OverrideBuildSettings:SWIFT_DISABLE_REQUIRED_ARCLITE string 'YES'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
-          call ${PLISTBUDDY_BIN} -c "Add OverrideBuildSettings:SWIFT_LINK_OBJC_RUNTIME string 'YES'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
           call ${PLISTBUDDY_BIN} -c "Add OverrideBuildSettings:SWIFT_DEVELOPMENT_TOOLCHAIN string 'YES'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
           call ${PLISTBUDDY_BIN} -c "Add OverrideBuildSettings:SWIFT_USE_DEVELOPMENT_TOOLCHAIN_RUNTIME string '${SWIFT_USE_DEVELOPMENT_TOOLCHAIN_RUNTIME}'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
           call ${PLISTBUDDY_BIN} -c "Add OverrideBuildSettings:OTHER_SWIFT_FLAGS string '\$(inherited) -plugin-path ${TOOLCHAIN_PLUGIN_PATH_DESCRIPTOR}'" "${DARWIN_TOOLCHAIN_INFO_PLIST}"
@@ -3171,7 +3172,7 @@ function build_and_test_installable_package() {
             echo "-- Create Installer --"
             call "${SWIFT_SOURCE_DIR}/utils/toolchain-installer" "${host_install_destdir}${TOOLCHAIN_PREFIX}/" "${DARWIN_TOOLCHAIN_BUNDLE_IDENTIFIER}" \
                 "${DARWIN_TOOLCHAIN_INSTALLER_CERT}" "${DARWIN_TOOLCHAIN_INSTALLER_PACKAGE}" "${DARWIN_TOOLCHAIN_INSTALL_LOCATION}" \
-                "${DARWIN_TOOLCHAIN_VERSION}" "${SWIFT_SOURCE_DIR}/utils/darwin-installer-scripts"
+                "${DARWIN_TOOLCHAIN_VERSION}" "${SWIFT_SOURCE_DIR}/utils/darwin-installer-scripts" "${DARWIN_DEPLOYMENT_VERSION_OSX}"
           fi
 
           # host_install_destdir contains the toolchain prefix.
diff --git a/utils/build-windows-toolchain.bat b/utils/build-windows-toolchain.bat
index 131c283eddc1e..ea4633fb394c6 100644
--- a/utils/build-windows-toolchain.bat
+++ b/utils/build-windows-toolchain.bat
@@ -19,9 +19,11 @@ set TEMP=%~dp0..\..\tmp
 mkdir %TEMP% 2>&1 1>nul
 echo set PYTHON_HOME=%PYTHON_HOME%> %TEMP%\call-build.cmd
 echo set SKIP_TESTS=%SKIP_TESTS%>> %TEMP%\call-build.cmd
-echo set SKIP_PACKAGING=%SKIP_PACKAGING%>> %TEMP%\call-build.cmd
+echo set INCLUDE_PACKAGING=%INCLUDE_PACKAGING%>> %TEMP%\call-build.cmd
 echo set SKIP_UPDATE_CHECKOUT=%SKIP_UPDATE_CHECKOUT%>> %TEMP%\call-build.cmd
 echo set REPO_SCHEME=%REPO_SCHEME%>> %TEMP%\call-build.cmd
+echo set WINDOWS_SDKS=%WINDOWS_SDKS%>> %TEMP%\call-build.cmd
+echo set HOST_ARCH_NAME=%HOST_ARCH_NAME%>> %TEMP%\call-build.cmd
 echo "%~f0">> %TEMP%\call-build.cmd
 start /i /b /wait cmd.exe /env=default /c "%TEMP%\call-build.cmd"
 set ec=%errorlevel%
@@ -64,20 +66,31 @@ set TestArg=-Test lld,lldb,swift,dispatch,foundation,xctest,swift-format,sourcek
 for %%I in (%SKIP_TESTS%) do (call set TestArg=%%TestArg:%%I,=%%)
 if "%TestArg:~-1%"=="," (set TestArg=%TestArg:~0,-1%) else (set TestArg= )
 
-:: Build the -SkipPackaging argument, if any
-set SkipPackagingArg=-SkipPackaging
-if not "%SKIP_PACKAGING%"=="1" set "SkipPackagingArg= "
+:: Build the packaging arguments (skipped for normal PRs and an added stage for toolchain PRs)
+set "PackagingArg=-SkipPackaging"
+if not "%INCLUDE_PACKAGING%"=="" set "PackagingArg=-Stage %PackageRoot%"
+
+:: Build the arguments related to Windows SDK builds
+set "WindowsSDKArgs=-Windows"
+if "%INCLUDE_PACKAGING%"=="" set "WindowsSDKArgs=%WindowsSDKArgs% -WindowsSDKLinkModes dynamic"
+if not "%WINDOWS_SDKS%"=="" set "WindowsSDKArgs=%WindowsSDKArgs% -WindowsSDKArchitectures %WINDOWS_SDKS%"
+
+:: Build the -HostArchName argument, if any.
+set "HostArchNameArg="
+if not "%HOST_ARCH_NAME%"=="" set "HostArchNameArg=-HostArchName %HOST_ARCH_NAME%"
 
 call :CloneRepositories || (exit /b 1)
 
 :: We only have write access to BuildRoot, so use that as the image root.
 powershell.exe -ExecutionPolicy RemoteSigned -File %~dp0build.ps1 ^
+  %HostArchNameArg% ^
   -SourceCache %SourceRoot% ^
   -BinaryCache %BuildRoot% ^
   -ImageRoot %BuildRoot% ^
-  %SkipPackagingArg% ^
+  %WindowsSDKArgs% ^
+  %PackagingArg% ^
   %TestArg% ^
-  -Stage %PackageRoot% ^
+  -IncludeSBoM ^
   -Summary || (exit /b 1)
 
 :: Clean up the module cache
diff --git a/utils/build.ps1 b/utils/build.ps1
index aa16beeed097c..49ba6b6a0a462 100644
--- a/utils/build.ps1
+++ b/utils/build.ps1
@@ -15,159 +15,208 @@ This script performs various steps associated with building the Swift toolchain:
 - Optionally stages build artifacts for CI
 
 .PARAMETER SourceCache
-The path to a directory where projects contributing to the Swift.
-toolchain have been cloned.
+The path to a directory where projects contributing to the Swift toolchain have
+been cloned.
+Default: 'S:\SourceCache'
 
 .PARAMETER BinaryCache
 The path to a directory where to write build system files and outputs.
+Default: 'S:\b'
 
 .PARAMETER ImageRoot
-The path to a directory that mimics a file system image root,
-under which "Library" and "Program Files" subdirectories will be created
-with the files installed by CMake.
+The path to a directory that mimics a file system image root, under which the
+"Program Files" subdirectories will be created with the files installed by CMake.
+Default: 'S:\'
 
-.PARAMETER CDebugFormat
-The debug information format for C/C++ code: dwarf or codeview.
-
-.PARAMETER SwiftDebugFormat
-The debug information format for Swift code: dwarf or codeview.
+.PARAMETER Stage
+The path to a directory where built msi's and the installer executable should be
+staged (for CI). Leave empty for local development builds.
 
-.PARAMETER AndroidAPILevel
-The API Level to target when building the Android SDKs
+.PARAMETER PinnedBuild
+The pinned bootstrap Swift toolchain used to build the Swift components with.
 
-.PARAMETER Android
-When set, build android SDKs.
+.PARAMETER PinnedSHA256
+The SHA256 for the pinned toolchain.
 
-.PARAMETER AndroidSDKs
-An array of architectures for which the Android Swift SDK should be built.
+.PARAMETER EnableCaching
+Enable build caching using sccache to speed up rebuilds. Requires sccache to be
+configured via environment variables. Recommended for repeated builds.
 
-.PARAMETER WindowsSDKs
-An array of architectures for which the Windows Swift SDK should be built.
+.PARAMETER IncludeSBoM
+Include Software Bill of Materials generation using syft. Used for compliance
+tracking.
 
 .PARAMETER ProductVersion
-The product version to be used when building the installer.
-Supports semantic version strings.
+The product version to be used when building the installer. Supports semantic
+version strings (e.g., "1.0.0"). Default: "0.0.0"
 
-.PARAMETER PinnedBuild
-The toolchain snapshot to build the early components with.
+.PARAMETER ToolchainIdentifier
+The toolchain version identifier for the toolchain being built.
+Default: Uses TOOLCHAIN_VERSION environment variable or "$USERNAME.development"
 
-.PARAMETER PinnedSHA256
-The SHA256 for the pinned toolchain.
+.PARAMETER HostArchName
+The architecture where the toolchain will execute. Automatically detected from
+system.  Valid values: AMD64, ARM64
+
+.PARAMETER DebugInfo
+Include debug information in the builds. Useful for debugging the toolchain
+itself.
+Note: This significantly increases build time and disk usage.
 
-.PARAMETER PinnedToolchainVariant
-The toolchain variant to use while building the toolchain. Defaults to
-`Asserts`.
+.PARAMETER CDebugFormat
+The debug information format for C/C++ code. Valid values: dwarf, codeview.
+Default: dwarf
+
+.PARAMETER SwiftDebugFormat
+The debug information format for Swift code. Valid values: dwarf, codeview.
+Default: dwarf
+
+.PARAMETER Android
+Build Android SDKs. Requires Android NDK to be available.
 
 .PARAMETER AndroidNDKVersion
 The version number of the Android NDK to be used.
+Format: r{number}[{letter}] (e.g., r27c)
+Default: "r27c"
+
+.PARAMETER AndroidAPILevel
+The API Level to target when building the Android SDKs. Must be between 1 and 36.
+Default: 28
+
+.PARAMETER AndroidSDKVersions
+An array of SDKs to build for the Android OS.
+Default: @("Android", "AndroidExperimental")
+
+.PARAMETER AndroidSDKArchitectures
+An array of architectures for which the Android Swift SDK should be built.
+Default: @("aarch64", "armv7", "i686", "x86_64")
+
+.PARAMETER Windows
+Build Windows SDKs.
 
 .PARAMETER WinSDKVersion
 The version number of the Windows SDK to be used.
 Overrides the value resolved by the Visual Studio command prompt.
 If no such Windows SDK is installed, it will be downloaded from nuget.
 
-.PARAMETER IncludeDS2
-Include the ds2 remote debug server in the SDK.
-This component is currently only supported in Android builds.
+.PARAMETER WindowsSDKVersions
+An array of SDKs to build for the Windows OS.
+Default: @("Windows", "WindowsExperimental")
 
-.PARAMETER SkipBuild
-If set, does not run the build phase.
-
-.PARAMETER SkipPackaging
-If set, skips building the msi's and installer
-
-.PARAMETER DebugInfo
-If set, debug information will be generated for the builds.
-
-.PARAMETER EnableCaching
-If true, use `sccache` to cache the build rules. Configuration of sccache must be done through
-the environment variables defined by the sccache project.
+.PARAMETER WindowsSDKArchitectures
+An array of architectures for which the Windows Swift SDK should be built.
+Default: @("X64","X86","ARM64")
 
 .PARAMETER Clean
-If true, clean non-compiler builds while building.
+Clean non-compiler builds while building. Use this for a fresh build when
+experiencing issues.
 
-.PARAMETER Test
-An array of names of projects to run tests for.
-'*' runs all tests
-
-.PARAMETER Stage
-The path to a directory where built msi's and the installer executable should be staged (for CI).
+.PARAMETER SkipBuild
+Skip the build phase entirely. Useful for testing packaging or other post-build
+steps.
 
-.PARAMETER BuildTo
-The name of a build step after which the script should terminate.
-For example: -BuildTo ToolsSupportCore
+.PARAMETER SkipPackaging
+Skip building the MSI installers and packaging. Useful for development builds.
 
-.PARAMETER ToBatch
-When set, runs the script in a special mode which outputs a listing of command invocations
-in batch file format instead of executing them.
+.PARAMETER Test
+An array of names of projects to run tests for. Use '*' to run all tests.
+Available tests: lld, lldb, swift, dispatch, foundation, xctest, swift-format, sourcekit-lsp
 
-.PARAMETER HostArchName
-The architecture where the toolchain will execute.
+.PARAMETER IncludeDS2
+Include the ds2 remote debug server in the SDK.
+This component is currently only supported in Android builds.
 
-.PARAMETER Variant
-The toolchain variant to build. Defaults to `Asserts`.
+.PARAMETER IncludeNoAsserts
+Build and include the no-assert toolchain variant in the output.
 
-.PARAMETER FoundationTestConfiguration
-Whether to run swift-foundation and swift-corelibs-foundation tests in a debug or release configuration.
+.PARAMETER Summary
+Display a build time summary at the end of the build. Helpful for performance analysis.
 
 .EXAMPLE
 PS> .\Build.ps1
 
 .EXAMPLE
-PS> .\Build.ps1 -WindowsSDKs x64 -ProductVersion 1.2.3 -Test foundation,xctest
+PS> .\Build.ps1 -WindowsSDKArchitectures x64 -ProductVersion 1.2.3 -Test foundation,xctest
 #>
 [CmdletBinding(PositionalBinding = $false)]
 param
 (
+  # Build Paths
   [System.IO.FileInfo] $SourceCache = "S:\SourceCache",
   [System.IO.FileInfo] $BinaryCache = "S:\b",
   [System.IO.FileInfo] $ImageRoot = "S:",
-  [ValidateSet("codeview", "dwarf")]
-  [string] $CDebugFormat = "dwarf",
-  [ValidateSet("codeview", "dwarf")]
-  [string] $SwiftDebugFormat = "dwarf",
-  [ValidateRange(1, 36)]
-  [int] $AndroidAPILevel = 28,
-  [string[]] $AndroidSDKs = @(),
-  [string[]] $WindowsSDKs = @("X64","X86","Arm64"),
-  [string] $ProductVersion = "0.0.0",
-  [string] $ToolchainIdentifier = $(if ($env:TOOLCHAIN_VERSION) { $env:TOOLCHAIN_VERSION } else { "$env:USERNAME.development" }),
+  [string] $Stage = "",
+
+  # (Pinned) Bootstrap Toolchain
   [string] $PinnedBuild = "",
   [ValidatePattern("^([A-Fa-f0-9]{64}|)$")]
   [string] $PinnedSHA256 = "",
   [string] $PinnedVersion = "",
-  [ValidateSet("Asserts", "NoAsserts")]
-  [string] $PinnedToolchainVariant = "Asserts",
+
+  # Build Caching
+  [switch] $EnableCaching,
   [ValidatePattern('^\d+(\.\d+)*$')]
-  [string] $PythonVersion = "3.9.10",
+  [string] $SCCacheVersion = "0.10.0",
+
+  # SBoM Support
+  [switch] $IncludeSBoM = $false,
+  [string] $SyftVersion = "1.29.1",
+
+  # Dependencies
+  [ValidatePattern('^\d+(\.\d+)*$')]
+  [string] $PythonVersion = "3.10.1",
+
+  # Toolchain Version Info
+  [string] $ProductVersion = "0.0.0",
+  [string] $ToolchainIdentifier = $(if ($env:TOOLCHAIN_VERSION) { $env:TOOLCHAIN_VERSION } else { "$env:USERNAME.development" }),
+
+  # Toolchain Cross-compilation
+  [ValidateSet("AMD64", "ARM64")]
+  [string] $HostArchName = $(if ($env:PROCESSOR_ARCHITEW6432) { $env:PROCESSOR_ARCHITEW6432 } else { $env:PROCESSOR_ARCHITECTURE }),
+  [object] $UseHostToolchain = $true,
+
+  # Debug Information
+  [switch] $DebugInfo,
+  [ValidateSet("codeview", "dwarf")]
+  [string] $CDebugFormat = "dwarf",
+  [ValidateSet("codeview", "dwarf")]
+  [string] $SwiftDebugFormat = "dwarf",
+
+  # Android SDK Options
+  [switch] $Android = $false,
   [ValidatePattern("^r(?:[1-9]|[1-9][0-9])(?:[a-z])?$")]
   [string] $AndroidNDKVersion = "r27c",
+  [ValidateRange(1, 36)]
+  [int] $AndroidAPILevel = 28,
+  [string[]] $AndroidSDKArchitectures = @("aarch64", "armv7", "i686", "x86_64"),
+  [ValidateSet("dynamic", "static")]
+  [string[]] $AndroidSDKLinkModes = @("dynamic", "static"),
+  [string[]] $AndroidSDKVersions = @("Android", "AndroidExperimental"),
+  [string] $AndroidSDKVersionDefault = "Android",
+
+  # Windows SDK Options
+  [switch] $Windows = $true,
   [ValidatePattern("^\d+\.\d+\.\d+(?:-\w+)?")]
   [string] $WinSDKVersion = "",
-  [switch] $Android = $false,
+  [string[]] $WindowsSDKArchitectures = @("X64","X86","Arm64"),
+  [ValidateSet("dynamic", "static")]
+  [string[]] $WindowsSDKLinkModes = @("dynamic", "static"),
+  [string[]] $WindowsSDKVersions = @("Windows", "WindowsExperimental"),
+  [string] $WindowsSDKVersionDefault = "Windows",
+
+  # Incremental Build Support
+  [switch] $Clean,
   [switch] $SkipBuild = $false,
   [switch] $SkipPackaging = $false,
-  [switch] $IncludeDS2 = $false,
   [string[]] $Test = @(),
-  [string] $Stage = "",
-  [ValidateSet("ArgumentParser", "ASN1", "BuildTools", "Certificates", "CMark",
-    "Collections", "Compilers", "Crypto", "CURL", "Dispatch", "DocC", "Driver",
-    "DS2", "ExperimentalRuntime", "Format", "Foundation", "FoundationMacros",
-    "IndexStoreDB", "Inspect", "Installer", "LLBuild", "LLVM", "LMDB",
-    "Markdown", "mimalloc", "PackageManager", "PlatformInfoPlist", "RegsGen2",
-    "Runtime", "Sanitizers", "SDKSettingsPlist", "SourceKitLSP", "SQLite",
-    "System", "Testing", "TestingMacros", "ToolsSupportCore", "XCTest", "XML2",
-    "ZLib")]
-  [string] $BuildTo = "",
-  [ValidateSet("AMD64", "ARM64")]
-  [string] $HostArchName = $(if ($env:PROCESSOR_ARCHITEW6432) { $env:PROCESSOR_ARCHITEW6432 } else { $env:PROCESSOR_ARCHITECTURE }),
-  [ValidateSet("Asserts", "NoAsserts")]
-  [string] $Variant = "Asserts",
-  [switch] $Clean,
-  [switch] $DebugInfo,
-  [switch] $EnableCaching,
+
+  [switch] $IncludeDS2 = $false,
+  [ValidateSet("none", "full", "thin")]
+  [string] $LTO = "none",
+  [switch] $IncludeNoAsserts = $false,
   [ValidateSet("debug", "release")]
   [string] $FoundationTestConfiguration = "debug",
+
   [switch] $Summary,
   [switch] $ToBatch
 )
@@ -198,38 +247,36 @@ if (($PinnedBuild -or $PinnedSHA256 -or $PinnedVersion) -and -not ($PinnedBuild
   throw "If any of PinnedBuild, PinnedSHA256, or PinnedVersion is set, all three must be set."
 }
 
-if ($Android -and ($AndroidSDKs.Length -eq 0)) {
-  # Enable all android SDKs by default.
-  $AndroidSDKs = @("aarch64","armv7","i686","x86_64")
-}
-
 # Work around limitations of cmd passing in array arguments via powershell.exe -File
-if ($AndroidSDKs.Length -eq 1) { $AndroidSDKs = $AndroidSDKs[0].Split(",") }
-if ($WindowsSDKs.Length -eq 1) { $WindowsSDKs = $WindowsSDKs[0].Split(",") }
-if ($Test.Length -eq 1) { $Test = $Test[0].Split(",") }
+if ($AndroidSDKVersions.Length -eq 1) { $AndroidSDKVersions = $AndroidSDKVersions[0].Split(",") }
+if ($AndroidSDKArchitectures.Length -eq 1) { $AndroidSDKArchitectures = $AndroidSDKArchitectures[0].Split(",") }
 
-if ($AndroidSDKs.Length -gt 0) {
-  # Always enable android when one of the SDKs is specified.
-  $Android = $true
-}
+if ($WindowsSDKVersions.Length -eq 1) { $WindowsSDKVersions = $WindowsSDKVersions[0].Split(",") }
+if ($WindowsSDKArchitectures.Length -eq 1) { $WindowsSDKArchitectures = $WindowsSDKArchitectures[0].Split(",") }
+
+if ($Test.Length -eq 1) { $Test = $Test[0].Split(",") }
 
 if ($Test -contains "*") {
   # Explicitly don't include llbuild yet since tests are known to fail on Windows
   $Test = @("lld", "lldb", "swift", "dispatch", "foundation", "xctest", "swift-format", "sourcekit-lsp")
 }
 
+if ($UseHostToolchain -is [string]) {
+  $UseHostToolchain = [System.Convert]::ToBoolean($UseHostToolchain)
+}
+
 ## Declare static build and build tool parameters.
 
 $DefaultPinned = @{
   AMD64 = @{
-    PinnedBuild = "https://download.swift.org/swift-6.0.3-release/windows10/swift-6.0.3-RELEASE/swift-6.0.3-RELEASE-windows10.exe";
-    PinnedSHA256 = "AB205D83A38047882DB80E6A88C7D33B651F3BAC96D4515D7CBA5335F37999D3";
-    PinnedVersion = "6.0.3";
+    PinnedBuild = "https://download.swift.org/swift-6.1.2-release/windows10/swift-6.1.2-RELEASE/swift-6.1.2-RELEASE-windows10.exe";
+    PinnedSHA256 = "92A0323ED7DD333C3B05E6E0E428F3A91C77D159F6CCFC8626A996F2ACE09A0B";
+    PinnedVersion = "6.1.2";
   };
   ARM64 = @{
-    PinnedBuild = "https://download.swift.org/swift-6.0.3-release/windows10-arm64/swift-6.0.3-RELEASE/swift-6.0.3-RELEASE-windows10-arm64.exe";
-    PinnedSHA256 = "81474651E59A9955C9E6A389EF53ABD61631FFC62C63A2A02977271019E7C722";
-    PinnedVersion = "6.0.3";
+    PinnedBuild = "https://download.swift.org/swift-6.1.2-release/windows10-arm64/swift-6.1.2-RELEASE/swift-6.1.2-RELEASE-windows10-arm64.exe";
+    PinnedSHA256 = "121FB407E578178F82DCCF39A4D03527873D8F7611A801A8FC26DA52503A0C5C";
+    PinnedVersion = "6.1.2";
   };
 }
 
@@ -250,6 +297,8 @@ $KnownPlatforms = @{
     };
     BinaryDir = "bin64a";
     Cache = @{};
+    DefaultSDK = $WindowsSDKVersionDefault;
+    LinkModes = $WindowsSDKLinkModes;
   };
 
   WindowsX64 = @{
@@ -263,6 +312,8 @@ $KnownPlatforms = @{
     };
     BinaryDir = "bin64";
     Cache = @{};
+    DefaultSDK = $WindowsSDKVersionDefault;
+    LinkModes = $WindowsSDKLinkModes;
   };
 
   WindowsX86  = @{
@@ -276,6 +327,8 @@ $KnownPlatforms = @{
     };
     BinaryDir = "bin32";
     Cache = @{};
+    DefaultSDK = $WindowsSDKVersionDefault;
+    LinkModes = $WindowsSDKLinkModes;
   };
 
   AndroidARMv7 = @{
@@ -289,6 +342,8 @@ $KnownPlatforms = @{
     };
     BinaryDir = "bin32a";
     Cache = @{};
+    DefaultSDK = $AndroidSDKVersionDefault;
+    LinkModes = $AndroidSDKLinkModes;
   };
 
   AndroidARM64 = @{
@@ -302,6 +357,8 @@ $KnownPlatforms = @{
     };
     BinaryDir = "bin64a";
     Cache = @{};
+    DefaultSDK = $AndroidSDKVersionDefault;
+    LinkModes = $AndroidSDKLinkModes;
   };
 
   AndroidX86 = @{
@@ -315,6 +372,8 @@ $KnownPlatforms = @{
     };
     BinaryDir = "bin32";
     Cache = @{};
+    DefaultSDK = $AndroidSDKVersionDefault;
+    LinkModes = $AndroidSDKLinkModes;
   };
 
   AndroidX64 = @{
@@ -328,6 +387,8 @@ $KnownPlatforms = @{
     };
     BinaryDir = "bin64";
     Cache = @{};
+    DefaultSDK = $AndroidSDKVersionDefault;
+    LinkModes = $AndroidSDKLinkModes;
   };
 }
 
@@ -348,29 +409,54 @@ $KnownPythons = @{
       URL = "https://www.nuget.org/api/v2/package/pythonarm64/3.9.10";
       SHA256 = "429ada77e7f30e4bd8ff22953a1f35f98b2728e84c9b1d006712561785641f69";
     };
-  }
+  };
+  "3.10.1" = @{
+    AMD64 = @{
+      URL = "https://www.nuget.org/api/v2/package/python/3.10.1";
+      SHA256 = "987a0e446d68900f58297bc47dc7a235ee4640a49dace58bc9f573797d3a8b33";
+    };
+    ARM64 = @{
+      URL = "https://www.nuget.org/api/v2/package/pythonarm64/3.10.1";
+      SHA256 = "16becfccedf1269ff0b8695a13c64fac2102a524d66cecf69a8f9229a43b10d3";
+    };
+  };
 }
 
-$PythonWheels = @{
+$PythonModules = @{
   "packaging" = @{
-    File = "packaging-24.1-py3-none-any.whl";
-    URL = "https://files.pythonhosted.org/packages/08/aa/cc0199a5f0ad350994d660967a8efb233fe0416e4639146c089643407ce6/packaging-24.1-py3-none-any.whl";
-    SHA256 = "5b8f2217dbdbd2f7f384c41c628544e6d52f2d0f53c6d0c3ea61aa5d1d7ff124";
+    Version = "24.1";
+    SHA256 = "026ed72c8ed3fcce5bf8950572258698927fd1dbda10a5e981cdf0ac37f4f002";
+    Dependencies = @();
   };
-  "distutils" = @{
-    File = "setuptools-75.1.0-py3-none-any.whl";
-    URL = "https://files.pythonhosted.org/packages/ff/ae/f19306b5a221f6a436d8f2238d5b80925004093fa3edea59835b514d9057/setuptools-75.1.0-py3-none-any.whl";
-    SHA256 = "35ab7fd3bcd95e6b7fd704e4a1539513edad446c097797f2985e0e4b960772f2";
+  "setuptools" = @{
+    Version = "75.1.0";
+    SHA256 = "d59a21b17a275fb872a9c3dae73963160ae079f1049ed956880cd7c09b120538";
+    Dependencies = @();
   };
   "psutil" = @{
-    File = "psutil-6.1.0-cp37-abi3-win_amd64.whl";
-    URL = "https://files.pythonhosted.org/packages/11/91/87fa6f060e649b1e1a7b19a4f5869709fbf750b7c8c262ee776ec32f3028/psutil-6.1.0-cp37-abi3-win_amd64.whl";
-    SHA256 = "a8fb3752b491d246034fa4d279ff076501588ce8cbcdbb62c32fd7a377d996be";
+    Version = "6.1.0";
+    SHA256 = "353815f59a7f64cdaca1c0307ee13558a0512f6db064e92fe833784f08539c7a";
+    Dependencies = @();
+  };
+  "argparse" = @{
+    Version = "1.4.0";
+    SHA256 = "c31647edb69fd3d465a847ea3157d37bed1f95f19760b11a47aa91c04b666314";
+    Dependencies = @();
   };
-  "unittest2" = @{
-    File = "unittest2-1.1.0-py2.py3-none-any.whl";
-    URL = "https://files.pythonhosted.org/packages/72/20/7f0f433060a962200b7272b8c12ba90ef5b903e218174301d0abfd523813/unittest2-1.1.0-py2.py3-none-any.whl";
-    SHA256 = "13f77d0875db6d9b435e1d4f41e74ad4cc2eb6e1d5c824996092b3430f088bb8";
+  "six" = @{
+    Version = "1.17.0";
+    SHA256 = "4721f391ed90541fddacab5acf947aa0d3dc7d27b2e1e8eda2be8970586c3274";
+    Dependencies = @();
+  };
+  "traceback2" = @{
+    Version = "1.4.0";
+    SHA256 = "8253cebec4b19094d67cc5ed5af99bf1dba1285292226e98a31929f87a5d6b23";
+    Dependencies = @();
+  };
+  "linecache2" = @{
+    Version = "1.0.0";
+    SHA256 = "e78be9c0a0dfcbac712fe04fbf92b96cddae80b1b842f24248214c8496f006ef";
+    Dependencies = @();
   };
 }
 
@@ -387,6 +473,44 @@ $KnownNDKs = @{
   }
 }
 
+$KnownSCCache = @{
+  "0.9.1" = @{
+    AMD64 = @{
+      URL = "https://github.com/mozilla/sccache/releases/download/v0.9.1/sccache-v0.9.1-x86_64-pc-windows-msvc.zip"
+      SHA256 = "9C862BCAEF62804F2124DFC2605A0204F4FE0C5FA337BA4264E9BCAE9D2BA487"
+      Path = [IO.Path]::Combine("$BinaryCache\sccache-0.9.1\sccache-v0.9.1-x86_64-pc-windows-msvc", "sccache.exe");
+    }
+    ARM64 = @{
+      URL = "https://github.com/mozilla/sccache/releases/download/v0.9.1/sccache-v0.9.1-aarch64-pc-windows-msvc.tar.gz"
+      SHA256 = "99BD024919430DE3C741658ADC60334305A61C0A109F7A334C030F0BB56007A6"
+      Path = [IO.Path]::Combine("$BinaryCache\sccache-0.9.1\sccache-v0.9.1-aarch64-pc-windows-msvc", "sccache.exe")
+    }
+  }
+
+  "0.10.0" = @{
+    AMD64 = @{
+      URL = "https://github.com/mozilla/sccache/releases/download/v0.10.0/sccache-v0.10.0-x86_64-pc-windows-msvc.zip"
+      SHA256 = "6D8823B5C13E0DBA776D88C537229256ECB2F01A1D775B507FD141CB55D30578"
+      Path = [IO.Path]::Combine("$BinaryCache\sccache-0.10.0\sccache-v0.10.0-x86_64-pc-windows-msvc", "sccache.exe")
+    }
+    ARM64 = @{
+      URL = "https://github.com/mozilla/sccache/releases/download/v0.10.0/sccache-v0.10.0-aarch64-pc-windows-msvc.tar.gz"
+      SHA256 = "5FD6CD6DD474E91C37510719BF27CFE1826F929E40DD383C22A7B96DA9A5458D"
+      Path = [IO.Path]::Combine("$BinaryCache\sccache-0.10.0\sccache-v0.10.0-aarch64-pc-windows-msvc", "sccache.exe")
+    }
+  }
+}
+
+$KnownSyft = @{
+  "1.29.1" = @{
+    AMD64 = @{
+      URL = "https://github.com/anchore/syft/releases/download/v1.29.1/syft_1.29.1_windows_amd64.zip"
+      SHA256 = "3C67CD9AF40CDCC7FFCE041C8349B4A77F33810184820C05DF23440C8E0AA1D7"
+      Path = [IO.Path]::Combine("$BinaryCache\syft-1.29.1", "syft.exe")
+    }
+  }
+}
+
 $BuildArchName = if ($env:PROCESSOR_ARCHITEW6432) { $env:PROCESSOR_ARCHITEW6432 } else { $env:PROCESSOR_ARCHITECTURE }
 # TODO: Support other cross-compilation scenarios.
 $BuildOS = [OS]::Windows
@@ -396,8 +520,32 @@ $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.e
 $VSInstallRoot = & $vswhere -nologo -latest -products "*" -all -prerelease -property installationPath
 $msbuild = "$VSInstallRoot\MSBuild\Current\Bin\$BuildArchName\MSBuild.exe"
 
+function Get-CMake {
+  try {
+    return (Get-Command "cmake.exe" -ErrorAction Stop).Source
+  } catch {
+    if (Test-Path -Path "${VSInstallRoot}\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin" -PathType Container) {
+      return "${VSInstallRoot}\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe"
+    }
+  }
+  throw "CMake not found on Path nor in the Visual Studio Installation. Please Install CMake to continue."
+}
+
+function Get-Ninja {
+  try {
+    return (Get-Command "Ninja.exe" -ErrorAction Stop).Source
+  } catch {
+      if (Test-Path -Path "${VSInstallRoot}\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja" -PathType Container) {
+        return "${VSInstallRoot}\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja\ninja.exe"
+      }
+  }
+  throw "Ninja not found on Path nor in the Visual Studio Installation. Please Install Ninja to continue."
+}
+
+$cmake = Get-CMake
+$ninja = Get-Ninja
+
 $NugetRoot = "$BinaryCache\nuget"
-$LibraryRoot = "$ImageRoot\Library"
 
 ## Select and prepare build tools, platforms, parameters, etc.
 
@@ -431,7 +579,7 @@ if ($Android -and ($HostPlatform -ne $KnownPlatforms["WindowsX64"])) {
 }
 
 # Resolve the architectures received as argument
-$AndroidSDKPlatforms = @($AndroidSDKs | ForEach-Object {
+$AndroidSDKBuilds = @($AndroidSDKArchitectures | ForEach-Object {
   switch ($_) {
     "aarch64" { $KnownPlatforms["AndroidARM64"] }
     "armv7" { $KnownPlatforms["AndroidARMv7"] }
@@ -441,7 +589,7 @@ $AndroidSDKPlatforms = @($AndroidSDKs | ForEach-Object {
   }
 })
 
-$WindowsSDKPlatforms = @($WindowsSDKs | ForEach-Object {
+$WindowsSDKBuilds = @($WindowsSDKArchitectures | ForEach-Object {
   switch ($_) {
     "X64" { $KnownPlatforms["WindowsX64"] }
     "X86" { $KnownPlatforms["WindowsX86"] }
@@ -453,6 +601,7 @@ $WindowsSDKPlatforms = @($WindowsSDKs | ForEach-Object {
 ## Helpers for logging and timing build steps.
 
 $TimingData = New-Object System.Collections.Generic.List[System.Object]
+$CurrentOperation = $null
 
 function Add-TimingData {
   param
@@ -461,37 +610,100 @@ function Add-TimingData {
     [Hashtable] $Platform,
     [Parameter(Mandatory)]
     [string] $BuildStep,
-    [Parameter(Mandatory)]
-    [System.TimeSpan] $ElapsedTime
+    [PSCustomObject] $Parent = $null
   )
 
-  $TimingData.Add([PSCustomObject]@{
+  $TimingEntry = [PSCustomObject]@{
     Arch = $Platform.Architecture.LLVMName
     Platform = $Platform.OS.ToString()
     "Build Step" = $BuildStep
-    "Elapsed Time" = $ElapsedTime
-  })
+    "Elapsed Time" = [TimeSpan]::Zero
+    Parent = $Parent
+    Children = @()
+  }
+
+  if ($Parent) {
+    $Parent.Children += $TimingEntry
+  }
+
+  $TimingData.Add($TimingEntry)
+  return $TimingEntry
+}
+
+function Record-OperationTime {
+  param
+  (
+    [Parameter(Mandatory)]
+    [Hashtable] $Platform,
+    [Parameter(Mandatory)]
+    [string] $BuildStep,
+    [Parameter(Mandatory)]
+    [ScriptBlock] $ScriptBlock
+  )
+  if (!$Summary) {
+    & $ScriptBlock
+    return
+  }
+
+  $Stopwatch = [Diagnostics.Stopwatch]::StartNew()
+  $TimingEntry = Add-TimingData $Platform $BuildStep $script:CurrentOperation
+  $script:CurrentOperation = $TimingEntry
+
+  try {
+    & $ScriptBlock
+  } finally {
+    $Stopwatch.Stop()
+    $TimingEntry."Elapsed Time" = $Stopwatch.Elapsed
+    $script:CurrentOperation = $TimingEntry.Parent
+  }
+}
+
+function Flatten-TimingEntry {
+  param(
+    [Parameter(Mandatory)]
+    [PSCustomObject] $Entry,
+    [Parameter(Mandatory)]
+    [TimeSpan] $TotalTime,
+    [int] $Depth = 0
+  )
+
+  $Indent = "  " * $Depth
+  $Percentage = [math]::Round(($Entry."Elapsed Time".TotalSeconds / $TotalTime.TotalSeconds) * 100, 1)
+  $FormattedTime = "{0:hh\:mm\:ss\.ff}" -f $Entry."Elapsed Time"
+
+  [PSCustomObject]@{
+    "Build Step" = "$Indent$($Entry.'Build Step')"
+    Platform = $Entry.Platform
+    Arch = $Entry.Arch
+    "Elapsed Time" = $FormattedTime
+    "%" = "$Percentage%"
+  }
+
+  $SortedChildren = $Entry.Children | Sort-Object -Descending -Property "Elapsed Time"
+  foreach ($Child in $SortedChildren) {
+    Flatten-TimingEntry $Child $TotalTime ($Depth + 1)
+  }
 }
 
 function Write-Summary {
   Write-Host "Summary:" -ForegroundColor Cyan
 
+  if ($EnableCaching) {
+    Write-Host "SCCache:" -ForegroundColor Green
+    Invoke-Program (Get-SCCache).Path --show-stats
+  }
+
   $TotalTime = [TimeSpan]::Zero
   foreach ($Entry in $TimingData) {
-    $TotalTime = $TotalTime.Add($Entry."Elapsed Time")
+    if (-not $Entry.Parent) {
+      $TotalTime = $TotalTime.Add($Entry."Elapsed Time")
+    }
   }
 
-  $SortedData = $TimingData | ForEach-Object {
-    $Percentage = [math]::Round(($_.("Elapsed Time").TotalSeconds / $TotalTime.TotalSeconds) * 100, 1)
-    $FormattedTime = "{0:hh\:mm\:ss\.ff}" -f $_."Elapsed Time"
-    [PSCustomObject]@{
-      "Build Step" = $_."Build Step"
-      Platform = $_.Platform
-      Arch = $_.Arch
-      "Elapsed Time" = $FormattedTime
-      "%" = "$Percentage%"
-    }
-  } | Sort-Object -Descending -Property "Elapsed Time"
+  $RootEntries = $TimingData | Where-Object { -not $_.Parent } | Sort-Object -Descending -Property "Elapsed Time"
+  $Result = foreach ($RootEntry in $RootEntries) {
+    Flatten-TimingEntry $RootEntry $TotalTime
+  }
 
   $FormattedTotalTime = "{0:hh\:mm\:ss\.ff}" -f $TotalTime
   $TotalRow = [PSCustomObject]@{
@@ -502,7 +714,7 @@ function Write-Summary {
     "%" = "100.0%"
   }
 
-  @($SortedData) + $TotalRow | Format-Table -AutoSize
+  @($Result) + $TotalRow | Format-Table -AutoSize
 }
 
 function Get-AndroidNDK {
@@ -523,6 +735,10 @@ function Get-BisonExecutable {
   return Join-Path -Path $BinaryCache -ChildPath "win_flex_bison\win_bison.exe"
 }
 
+function Get-SCCache {
+  return $KnownSCCache[$SCCacheVersion][$BuildArchName]
+}
+
 function Get-PythonPath([Hashtable] $Platform) {
   return [IO.Path]::Combine("$BinaryCache\", "Python$($Platform.Architecture.CMakeName)-$PythonVersion")
 }
@@ -535,26 +751,40 @@ function Get-PythonScriptsPath {
   return [IO.Path]::Combine((Get-PythonPath $BuildPlatform), "tools", "Scripts")
 }
 
+function Get-Syft {
+  return $KnownSyft[$SyftVersion][$BuildArchName]
+}
+
+function Get-SyftPath([Hashtable] $Platform) {
+  return [IO.Path]::Combine("$BinaryCache\", "syft-$SyftVersion")
+}
+
+function Get-SyftExecutable {
+  return [IO.Path]::Combine((Get-SyftPath $BuildPlatform), "syft.exe")
+}
+
 function Get-InstallDir([Hashtable] $Platform) {
   if ($Platform -eq $HostPlatform) {
-    $ProgramFilesName = "Program Files"
-  } elseif ($Platform -eq $KnownPlatforms["WindowsX86"]) {
-    $ProgramFilesName = "Program Files (x86)"
-  } elseif (($HostPlatform -eq $KnownPlatforms["WindowsARM64"]) -and ($Platform -eq $KnownPlatforms["WindowsX64"])) {
-    # x64 programs actually install under "Program Files" on arm64,
-    # but this would conflict with the native installation.
-    $ProgramFilesName = "Program Files (Amd64)"
-  } else {
-    # arm64 cannot be installed on x64
-    return $null
+    return [IO.Path]::Combine("$ImageRoot\", "Program Files", "Swift")
   }
-  return "$ImageRoot\$ProgramFilesName\Swift"
+  if ($Platform -eq $KnownPlatforms["WindowsARM64"]) {
+    return [IO.Path]::Combine("$ImageRoot\", "Program Files (Arm64)", "Swift")
+  }
+  if ($Platform -eq $KnownPlatforms["WindowsX64"]) {
+    return [IO.Path]::Combine("$ImageRoot\", "Program Files (Amd64)", "Swift")
+  }
+  if ($Platform -eq $KnownPlatforms["WindowsX86"]) {
+    return [IO.Path]::Combine("$ImageRoot\", "Program Files (x86)", "Swift")
+  }
+  throw "Unknown Platform"
 }
 
 # For dev productivity, install the host toolchain directly using CMake.
 # This allows iterating on the toolchain using ninja builds.
-$HostPlatform.ToolchainInstallRoot = "$(Get-InstallDir $HostPlatform)\Toolchains\$ProductVersion+$Variant"
-$BuildPlatform.ToolchainInstallRoot = "$(Get-InstallDir $BuildPlatform)\Toolchains\$ProductVersion+$Variant"
+$HostPlatform.ToolchainInstallRoot = "$(Get-InstallDir $HostPlatform)\Toolchains\$ProductVersion+Asserts"
+$HostPlatform.NoAssertsToolchainInstallRoot = "$(Get-InstallDir $HostPlatform)\Toolchains\$ProductVersion+NoAsserts"
+$BuildPlatform.ToolchainInstallRoot = "$(Get-InstallDir $BuildPlatform)\Toolchains\$ProductVersion+Asserts"
+$BuildPlatform.NoAssertsToolchainInstallRoot = "$(Get-InstallDir $BuildPlatform)\Toolchains\$ProductVersion+NoAsserts"
 
 # Build functions
 function Invoke-BuildStep {
@@ -566,52 +796,64 @@ function Invoke-BuildStep {
     [Parameter(Position=1, Mandatory)]
     [Hashtable] $Platform,
     [Parameter(ValueFromRemainingArguments)]
-    $RemainingArgs
+    [Object[]] $RemainingArgs
   )
 
-  if ($Summary) {
-    $Stopwatch = [Diagnostics.Stopwatch]::StartNew()
-  }
-
   $SplatArgs = @{}
-  foreach ($Arg in $RemainingArgs) {
-    if ($Arg -is [Hashtable]) {
-      $SplatArgs += $Arg
-    } elseif ($Arg -is [string]) {
-      $SplatArgs[$Arg.TrimStart('-')] = $true
-    } else {
-      throw "$Arg is unknown type: $($Arg.GetType())"
+  if ($RemainingArgs) {
+    $Enumerator = $RemainingArgs.GetEnumerator()
+    while ($Enumerator.MoveNext()) {
+      $Arg = $Enumerator.Current
+      if ($Arg -is [Hashtable]) {
+        $SplatArgs += $Arg
+      } elseif ($Arg -is [string] -and $Arg.StartsWith('-')) {
+        $ParamName = $Arg.TrimStart('-')
+        $HasNextArg = $RemainingArgs.IndexOf($Arg) -lt ($RemainingArgs.Count - 1)
+        if ($HasNextArg) {
+          $NextArg = $RemainingArgs[$RemainingArgs.IndexOf($Arg) + 1]
+          if ($NextArg -is [string] -and !$NextArg.StartsWith('-')) {
+            $SplatArgs[$ParamName] = $NextArg
+            $Enumerator.MoveNext() # Skip NextArg
+            continue
+          }
+        }
+        # Must be a flag.
+        $SplatArgs[$ParamName] = $true
+      } else {
+        throw "Positional parameter '$Arg' found. The Invoke-BuildStep function only supports named parameters after the required Name and Platform parameters."
+      }
     }
   }
 
-  & $Name $Platform @SplatArgs
-
-  if ($Summary) {
-    Add-TimingData $Platform $Name $Stopwatch.Elapsed
-  }
-  if ($Name.Replace("Build-", "") -eq $BuildTo) {
-    exit 0
+  Record-OperationTime $Platform $Name {
+    & $Name $Platform @SplatArgs
   }
 }
 
 enum Project {
   BuildTools
   RegsGen2
+  BootstrapFoundationMacros
+  BootstrapTestingMacros
 
+  CDispatch
   Compilers
   FoundationMacros
   TestingMacros
   ToolsSupportCore
   LLBuild
   ArgumentParser
+  SQLite
   Driver
   Crypto
   Collections
   ASN1
   Certificates
   System
+  Subprocess
   Build
   PackageManager
+  PackageManagerRuntime
   Markdown
   Format
   LMDB
@@ -629,8 +871,26 @@ enum Project {
   ClangBuiltins
   ClangRuntime
   SwiftInspect
-  ExperimentalRuntime
-  StaticFoundation
+  ExperimentalDynamicRuntime
+  ExperimentalDynamicOverlay
+  ExperimentalDynamicStringProcessing
+  ExperimentalDynamicSynchronization
+  ExperimentalDynamicDistributed
+  ExperimentalDynamicObservation
+  ExperimentalDynamicDispatch
+  ExperimentalDynamicDifferentiation
+  ExperimentalDynamicVolatile
+  ExperimentalDynamicFoundation
+  ExperimentalStaticRuntime
+  ExperimentalStaticOverlay
+  ExperimentalStaticStringProcessing
+  ExperimentalStaticSynchronization
+  ExperimentalStaticDistributed
+  ExperimentalStaticObservation
+  ExperimentalStaticDifferentiation
+  ExperimentalStaticVolatile
+  ExperimentalStaticDispatch
+  ExperimentalStaticFoundation
 }
 
 function Get-ProjectBinaryCache([Hashtable] $Platform, [Project] $Project) {
@@ -659,7 +919,7 @@ function Get-TargetInfo([Hashtable] $Platform) {
   # Cache the result of "swiftc -print-target-info" as $Platform.Cache.TargetInfo
   $CacheKey = "TargetInfo"
   if (-not $Platform.Cache.ContainsKey($CacheKey)) {
-    Invoke-IsolatingEnvVars {
+    [void](Invoke-IsolatingEnvVars {
       $env:Path = "$(Get-PinnedToolchainRuntime);$(Get-PinnedToolchainToolsDir);${env:Path}"
       $TargetInfo = & swiftc -target $Platform.Triple -print-target-info
       if ($LastExitCode -ne 0) {
@@ -667,7 +927,7 @@ function Get-TargetInfo([Hashtable] $Platform) {
       }
       $TargetInfo = $TargetInfo | ConvertFrom-JSON
       $Platform.Cache[$CacheKey] = $TargetInfo.target
-    }
+    })
   }
   return $Platform.Cache[$CacheKey]
 }
@@ -685,7 +945,9 @@ function Copy-File($Src, $Dst) {
     Write-Output "copy /Y `"$Src`" `"$Dst`""
   } else {
     New-Item -ItemType Directory -ErrorAction Ignore $DstDir | Out-Null
-    Copy-Item -Force $Src $Dst
+    Copy-Item -Force `
+      -Path $Src `
+      -Destination $Dst
   }
 }
 
@@ -695,7 +957,9 @@ function Copy-Directory($Src, $Dst) {
     Write-Output "copy /Y `"$Src`" `"$Dst`""
   } else {
     New-Item -ItemType Directory -ErrorAction Ignore $Dst | Out-Null
-    Copy-Item -Force -Recurse $Src $Dst
+    Copy-Item -Force -Recurse `
+      -Path $Src `
+      -Destination $Dst
   }
 }
 
@@ -706,7 +970,8 @@ function Move-Directory($Src, $Dst) {
     if (Test-Path -Path $Destination -Type Container) {
       Remove-Item -Path $Destination -Recurse -Force | Out-Null
     }
-    Move-Item -Path $Src -Destination $Dst -Force | Out-Null
+    New-Item -ItemType Directory -ErrorAction Ignore $Dst | Out-Null
+    Move-Item -Path $Src -Destination $Destination -Force | Out-Null
   }
 }
 
@@ -760,13 +1025,13 @@ function Invoke-Program() {
     if ($OutNull) {
       & $Executable @ExecutableArgs | Out-Null
     } elseif ($Silent) {
-      & $Executable @ExecutableArgs *> $null
+      & $Executable @ExecutableArgs | Out-Null 2>&1| Out-Null
     } elseif ($OutFile -and $ErrorFile) {
-      & $Executable @ExecutableArgs > $OutFile 2> $ErrorFile
+      & $Executable @ExecutableArgs | Out-File -FilePath $OutFile -Encoding UTF8 2>&1| Out-File -FilePath $ErrorFile -Encoding UTF8
     } elseif ($OutFile) {
-      & $Executable @ExecutableArgs > $OutFile
+      & $Executable @ExecutableArgs | Out-File -FilePath $OutFile -Encoding UTF8
     } elseif ($ErrorFile) {
-      & $Executable @ExecutableArgs 2> $ErrorFile
+      & $Executable @ExecutableArgs 2>&1| Out-File -FilePath $ErrorFile -Encoding UTF8
     } else {
       & $Executable @ExecutableArgs
     }
@@ -796,16 +1061,17 @@ function Invoke-IsolatingEnvVars([scriptblock]$Block) {
   foreach ($Var in (Get-ChildItem env:*).GetEnumerator()) {
     $OldVars.Add($Var.Key, $Var.Value)
   }
+  try {
+    & $Block
+  } finally {
+    Remove-Item env:*
+    foreach ($Var in $OldVars.GetEnumerator()) {
+      New-Item -Path "env:\$($Var.Key)" -Value $Var.Value -ErrorAction Ignore | Out-Null
+    }
 
-  & $Block
-
-  Remove-Item env:*
-  foreach ($Var in $OldVars.GetEnumerator()) {
-    New-Item -Path "env:\$($Var.Key)" -Value $Var.Value -ErrorAction Ignore | Out-Null
-  }
-
-  if ($ToBatch) {
-    Write-Output "endlocal"
+    if ($ToBatch) {
+      Write-Output "endlocal"
+    }
   }
 }
 
@@ -853,230 +1119,254 @@ function Invoke-VsDevShell([Hashtable] $Platform) {
 }
 
 function Get-Dependencies {
-  Write-Host "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Fetch-Dependencies ..." -ForegroundColor Cyan
-  $ProgressPreference = "SilentlyContinue"
+  Record-OperationTime $BuildPlatform "Get-Dependencies" {
+    Write-Host "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Get-Dependencies ..." -ForegroundColor Cyan
+    $ProgressPreference = "SilentlyContinue"
 
-  $WebClient = New-Object Net.WebClient
+    $WebClient = New-Object Net.WebClient
 
-  function DownloadAndVerify($URL, $Destination, $Hash) {
-    if (Test-Path $Destination) {
-      return
-    }
+    function DownloadAndVerify($URL, $Destination, $Hash) {
+      if (Test-Path $Destination) {
+        return
+      }
 
-    Write-Output "$Destination not found. Downloading ..."
-    if ($ToBatch) {
-      Write-Output "md `"$(Split-Path -Path $Destination -Parent)`""
-      Write-Output "curl.exe -sL $URL -o $Destination"
-      Write-Output "(certutil -HashFile $Destination SHA256) == $Hash || (exit /b)"
-    } else {
-      New-Item -ItemType Directory (Split-Path -Path $Destination -Parent) -ErrorAction Ignore | Out-Null
-      $WebClient.DownloadFile($URL, $Destination)
-      $SHA256 = Get-FileHash -Path $Destination -Algorithm SHA256
-      if ($SHA256.Hash -ne $Hash) {
-        throw "SHA256 mismatch ($($SHA256.Hash) vs $Hash)"
+      Write-Output "$Destination not found. Downloading ..."
+      if ($ToBatch) {
+        Write-Output "md `"$(Split-Path -Path $Destination -Parent)`""
+        Write-Output "curl.exe -sL $URL -o $Destination"
+        Write-Output "(certutil -HashFile $Destination SHA256) == $Hash || (exit /b)"
+      } else {
+        New-Item -ItemType Directory (Split-Path -Path $Destination -Parent) -ErrorAction Ignore | Out-Null
+        $WebClient.DownloadFile($URL, $Destination)
+        $SHA256 = Get-FileHash -Path $Destination -Algorithm SHA256
+        if ($SHA256.Hash -ne $Hash) {
+          throw "SHA256 mismatch ($($SHA256.Hash) vs $Hash)"
+        }
       }
     }
-  }
 
-  function Expand-ZipFile {
-    param
-    (
-        [string]$ZipFileName,
-        [string]$BinaryCache,
-        [string]$ExtractPath,
-        [bool]$CreateExtractPath = $true
-    )
+    function Expand-ZipFile {
+      param
+      (
+          [string]$ZipFileName,
+          [string]$BinaryCache,
+          [string]$ExtractPath,
+          [bool]$CreateExtractPath = $true
+      )
+
+      $source = Join-Path -Path $BinaryCache -ChildPath $ZipFileName
+      $destination = Join-Path -Path $BinaryCache -ChildPath $ExtractPath
+
+      # Check if the extracted directory already exists and is up to date.
+      if (Test-Path $destination) {
+          $zipLastWriteTime = (Get-Item $source).LastWriteTime
+          $extractedLastWriteTime = (Get-Item $destination).LastWriteTime
+          # Compare the last write times
+          if ($zipLastWriteTime -le $extractedLastWriteTime) {
+              Write-Output "'$ZipFileName' is already extracted and up to date."
+              return
+          }
+      }
 
-    $source = Join-Path -Path $BinaryCache -ChildPath $ZipFileName
-    $destination = Join-Path -Path $BinaryCache -ChildPath $ExtractPath
-
-    # Check if the extracted directory already exists and is up to date.
-    if (Test-Path $destination) {
-        $zipLastWriteTime = (Get-Item $source).LastWriteTime
-        $extractedLastWriteTime = (Get-Item $destination).LastWriteTime
-        # Compare the last write times
-        if ($zipLastWriteTime -le $extractedLastWriteTime) {
-            Write-Output "'$ZipFileName' is already extracted and up to date."
-            return
-        }
+      $destination = if ($CreateExtractPath) { $destination } else { $BinaryCache }
+
+      Write-Output "Extracting '$ZipFileName' ..."
+      New-Item -ItemType Directory -ErrorAction Ignore -Path $BinaryCache | Out-Null
+      Expand-Archive -Path $source -DestinationPath $destination -Force
     }
 
-    $destination = if ($CreateExtractPath) { $destination } else { $BinaryCache }
+    function Extract-Toolchain {
+      param
+      (
+          [string]$InstallerExeName,
+          [string]$BinaryCache,
+          [string]$ToolchainName
+      )
+
+      $source = Join-Path -Path $BinaryCache -ChildPath $InstallerExeName
+      $destination = Join-Path -Path $BinaryCache -ChildPath toolchains\$ToolchainName
+
+      # Check if the extracted directory already exists and is up to date.
+      if (Test-Path $destination) {
+          $installerWriteTime = (Get-Item $source).LastWriteTime
+          $extractedWriteTime = (Get-Item $destination).LastWriteTime
+          if ($installerWriteTime -le $extractedWriteTime) {
+              Write-Output "'$InstallerExeName' is already extracted and up to date."
+              return
+          }
+      }
 
-    Write-Output "Extracting '$ZipFileName' ..."
-    New-Item -ItemType Directory -ErrorAction Ignore -Path $BinaryCache | Out-Null
-    Expand-Archive -Path $source -DestinationPath $destination -Force
-  }
+      Write-Output "Extracting '$InstallerExeName' ..."
 
-  function Export-Toolchain {
-    param
-    (
-        [string]$InstallerExeName,
-        [string]$BinaryCache,
-        [string]$ToolchainName
-    )
-
-    $source = Join-Path -Path $BinaryCache -ChildPath $InstallerExeName
-    $destination = Join-Path -Path $BinaryCache -ChildPath toolchains\$ToolchainName
+      # The new runtime MSI is built to expand files into the immediate directory. So, setup the installation location.
+      New-Item -ItemType Directory -ErrorAction Ignore $BinaryCache\toolchains\$ToolchainName\LocalApp\Programs\Swift\Runtimes\$(Get-PinnedToolchainVersion)\usr\bin | Out-Null
+      Invoke-Program "$($WiX.Path)\wix.exe" -- burn extract $BinaryCache\$InstallerExeName -out $BinaryCache\toolchains\ -outba $BinaryCache\toolchains\
+      Get-ChildItem "$BinaryCache\toolchains\WixAttachedContainer" -Filter "*.msi" | ForEach-Object {
+        $LogFile = [System.IO.Path]::ChangeExtension($_.Name, "log")
+        $TARGETDIR = if ($_.Name -eq "rtl.msi") { "$BinaryCache\toolchains\$ToolchainName\LocalApp\Programs\Swift\Runtimes\$(Get-PinnedToolchainVersion)\usr\bin" } else { "$BinaryCache\toolchains\$ToolchainName" }
+        Invoke-Program -OutNull msiexec.exe /lvx! $BinaryCache\toolchains\$LogFile /qn /a $BinaryCache\toolchains\WixAttachedContainer\$($_.Name) ALLUSERS=0 TARGETDIR=$TARGETDIR
+      }
+    }
 
-    # Check if the extracted directory already exists and is up to date.
-    if (Test-Path $destination) {
-        $installerWriteTime = (Get-Item $source).LastWriteTime
-        $extractedWriteTime = (Get-Item $destination).LastWriteTime
-        if ($installerWriteTime -le $extractedWriteTime) {
-            Write-Output "'$InstallerExeName' is already extracted and up to date."
-            return
-        }
+    if ($IncludeSBoM) {
+      $syft = Get-Syft
+      DownloadAndVerify $syft.URL "$BinaryCache\syft-$SyftVersion.zip" $syft.SHA256
+      Expand-ZipFile syft-$SyftVersion.zip $BinaryCache syft-$SyftVersion
     }
 
-    Write-Output "Extracting '$InstallerExeName' ..."
+    if ($SkipBuild -and $SkipPackaging) { return }
 
-    # The new runtime MSI is built to expand files into the immediate directory. So, setup the installation location.
-    New-Item -ItemType Directory -ErrorAction Ignore $BinaryCache\toolchains\$PinnedToolchain\LocalApp\Programs\Swift\Runtimes\$(Get-PinnedToolchainVersion)\usr\bin | Out-Null
-    Invoke-Program "$($WiX.Path)\wix.exe" -- burn extract $BinaryCache\$InstallerExeName -out $BinaryCache\toolchains\ -outba $BinaryCache\toolchains\
-    Get-ChildItem "$BinaryCache\toolchains\WixAttachedContainer" -Filter "*.msi" | ForEach-Object {
-      $LogFile = [System.IO.Path]::ChangeExtension($_.Name, "log")
-      $TARGETDIR = if ($_.Name -eq "rtl.msi") { "$BinaryCache\toolchains\$ToolchainName\LocalApp\Programs\Swift\Runtimes\$(Get-PinnedToolchainVersion)\usr\bin" } else { "$BinaryCache\toolchains\$ToolchainName" }
-      Invoke-Program -OutNull msiexec.exe /lvx! $BinaryCache\toolchains\$LogFile /qn /a $BinaryCache\toolchains\WixAttachedContainer\$($_.Name) ALLUSERS=0 TARGETDIR=$TARGETDIR
+    $Stopwatch = [Diagnostics.Stopwatch]::StartNew()
+    if ($ToBatch) {
+      Write-Host -ForegroundColor Cyan "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Get-Dependencies..."
     }
-  }
 
-  if ($SkipBuild -and $SkipPackaging) { return }
+    DownloadAndVerify $WiX.URL "$BinaryCache\WiX-$($WiX.Version).zip" $WiX.SHA256
+    Expand-ZipFile WiX-$($WiX.Version).zip $BinaryCache WiX-$($WiX.Version)
 
-  $Stopwatch = [Diagnostics.Stopwatch]::StartNew()
-  if ($ToBatch) {
-    Write-Host -ForegroundColor Cyan "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Get-Dependencies..."
-  }
+    if ($SkipBuild) { return }
 
-  DownloadAndVerify $WiX.URL "$BinaryCache\WiX-$($WiX.Version).zip" $WiX.SHA256
-  Expand-ZipFile WiX-$($WiX.Version).zip $BinaryCache WiX-$($WiX.Version)
+    if ($EnableCaching) {
+      $SCCache = Get-SCCache
+      DownloadAndVerify $SCCache.URL "$BinaryCache\sccache-$SCCacheVersion.zip" $SCCache.SHA256
+      Expand-ZipFile sccache-$SCCacheVersion.zip $BinaryCache sccache-$SCCacheVersion
+    }
 
-  if ($SkipBuild) { return }
+    DownloadAndVerify $PinnedBuild "$BinaryCache\$PinnedToolchain.exe" $PinnedSHA256
 
-  DownloadAndVerify $PinnedBuild "$BinaryCache\$PinnedToolchain.exe" $PinnedSHA256
+    if ($Test -contains "lldb") {
+      # The make tool isn't part of MSYS
+      $GnuWin32MakeURL = "https://downloads.sourceforge.net/project/ezwinports/make-4.4.1-without-guile-w32-bin.zip"
+      $GnuWin32MakeHash = "fb66a02b530f7466f6222ce53c0b602c5288e601547a034e4156a512dd895ee7"
+      DownloadAndVerify $GnuWin32MakeURL "$BinaryCache\GnuWin32Make-4.4.1.zip" $GnuWin32MakeHash
+      Expand-ZipFile GnuWin32Make-4.4.1.zip $BinaryCache GnuWin32Make-4.4.1
+    }
 
-  if ($Test -contains "lldb") {
-    # The make tool isn't part of MSYS
-    $GnuWin32MakeURL = "https://downloads.sourceforge.net/project/ezwinports/make-4.4.1-without-guile-w32-bin.zip"
-    $GnuWin32MakeHash = "fb66a02b530f7466f6222ce53c0b602c5288e601547a034e4156a512dd895ee7"
-    DownloadAndVerify $GnuWin32MakeURL "$BinaryCache\GnuWin32Make-4.4.1.zip" $GnuWin32MakeHash
-    Expand-ZipFile GnuWin32Make-4.4.1.zip $BinaryCache GnuWin32Make-4.4.1
-  }
+    # TODO(compnerd) stamp/validate that we need to re-extract
+    New-Item -ItemType Directory -ErrorAction Ignore $BinaryCache\toolchains | Out-Null
+    Extract-Toolchain "$PinnedToolchain.exe" $BinaryCache $PinnedToolchain.TrimStart("swift-").TrimEnd("-a-windows10")
 
-  # TODO(compnerd) stamp/validate that we need to re-extract
-  New-Item -ItemType Directory -ErrorAction Ignore $BinaryCache\toolchains | Out-Null
-  Export-Toolchain "$PinnedToolchain.exe" $BinaryCache $PinnedToolchain
+    function Get-KnownPython([string] $ArchName) {
+      if (-not $KnownPythons.ContainsKey($PythonVersion)) {
+        throw "Unknown python version: $PythonVersion"
+      }
+      return $KnownPythons[$PythonVersion].$ArchName
+    }
 
-  function Get-KnownPython([string] $ArchName) {
-    if (-not $KnownPythons.ContainsKey($PythonVersion)) {
-      throw "Unknown python version: $PythonVersion"
+    function Install-Python([string] $ArchName) {
+      $Python = Get-KnownPython $ArchName
+      DownloadAndVerify $Python.URL "$BinaryCache\Python$ArchName-$PythonVersion.zip" $Python.SHA256
+      if (-not $ToBatch) {
+        Expand-ZipFile Python$ArchName-$PythonVersion.zip "$BinaryCache" Python$ArchName-$PythonVersion
+      }
     }
-    return $KnownPythons[$PythonVersion].$ArchName
-  }
 
-  function Install-Python([string] $ArchName) {
-    $Python = Get-KnownPython $ArchName
-    DownloadAndVerify $Python.URL "$BinaryCache\Python$ArchName-$PythonVersion.zip" $Python.SHA256
-    if (-not $ToBatch) {
-      Expand-ZipFile Python$ArchName-$PythonVersion.zip "$BinaryCache" Python$ArchName-$PythonVersion
+    function Install-PIPIfNeeded() {
+      try {
+        Invoke-Program -Silent "$(Get-PythonExecutable)" -m pip
+      } catch {
+        Write-Output "Installing pip ..."
+        Invoke-Program -OutNull "$(Get-PythonExecutable)" '-I' -m ensurepip -U --default-pip
+      } finally {
+        Write-Output "pip installed."
+      }
     }
-  }
 
-  function Install-PIPIfNeeded() {
-    try {
-      Invoke-Program -Silent "$(Get-PythonExecutable)" -m pip
-    } catch {
-      Write-Output "Installing pip ..."
-      Invoke-Program -OutNull "$(Get-PythonExecutable)" '-I' -m ensurepip -U --default-pip
-    } finally {
-      Write-Output "pip installed."
+    function Test-PythonModuleInstalled([string] $ModuleName) {
+      try {
+        Invoke-Program -Silent "$(Get-PythonExecutable)" -c "import $ModuleName"
+        return $true;
+      } catch {
+        return $false;
+      }
     }
-  }
 
-  function Install-PythonWheel([string] $ModuleName) {
-    try {
-      Invoke-Program -Silent "$(Get-PythonExecutable)" -c "import $ModuleName"
-    } catch {
-      $Wheel = $PythonWheels[$ModuleName]
-      DownloadAndVerify $Wheel.URL "$BinaryCache\python\$($Wheel.File)" $Wheel.SHA256
-      Write-Output "Installing '$($Wheel.File)' ..."
-      Invoke-Program -OutNull "$(Get-PythonExecutable)" '-I' -m pip install "$BinaryCache\python\$($Wheel.File)" --disable-pip-version-check
-    } finally {
+    function Install-PythonModule([string] $ModuleName) {
+      if (Test-PythonModuleInstalled $ModuleName) {
+        Write-Output "$ModuleName already installed."
+        return;
+      }
+      $TempRequirementsTxt = New-TemporaryFile
+      $Module = $PythonModules[$ModuleName]
+      $Dependencies = $Module["Dependencies"]
+      Write-Output "$ModuleName==$($Module.Version) --hash=`"sha256:$($Module.SHA256)`"" >> $TempRequirementsTxt
+      for ($i = 0; $i -lt $Dependencies.Length; $i++) {
+        $Dependency = $PythonModules[$Dependencies[$i]]
+        Write-Output "$($Dependencies[$i])==$($Dependency.Version) --hash=`"sha256:$($Dependency.SHA256)`"" >> $TempRequirementsTxt
+      }
+      Invoke-Program -OutNull "$(Get-PythonExecutable)" '-I' -m pip install -r $TempRequirementsTxt --require-hashes --no-binary==:all: --disable-pip-version-check
       Write-Output "$ModuleName installed."
     }
-  }
 
-  function Install-PythonModules() {
-    Install-PIPIfNeeded
-    Install-PythonWheel "packaging" # For building LLVM 18+
-    Install-PythonWheel "distutils" # Required for SWIG support
-    if ($Test -contains "lldb") {
-      Install-PythonWheel "psutil" # Required for testing LLDB
-      $env:Path = "$(Get-PythonScriptsPath);$env:Path" # For unit.exe
-      Install-PythonWheel "unittest2" # Required for testing LLDB
+    function Install-PythonModules() {
+      Install-PIPIfNeeded
+      Install-PythonModule "packaging" # For building LLVM 18+
+      Install-PythonModule "setuptools" # Required for SWIG support
+      if ($Test -contains "lldb") {
+        Install-PythonModule "psutil" # Required for testing LLDB
+      }
     }
-  }
 
-  Install-Python $HostArchName
-  if ($IsCrossCompiling) {
-    Install-Python $BuildArchName
-  }
+    Install-Python $HostArchName
+    if ($IsCrossCompiling) {
+      Install-Python $BuildArchName
+    }
 
-  # Ensure Python modules that are required as host build tools
-  Install-PythonModules
+    # Ensure Python modules that are required as host build tools
+    Install-PythonModules
 
-  if ($Android) {
-    $NDK = Get-AndroidNDK
-    DownloadAndVerify $NDK.URL "$BinaryCache\android-ndk-$AndroidNDKVersion-windows.zip" $NDK.SHA256
-    Expand-ZipFile -ZipFileName "android-ndk-$AndroidNDKVersion-windows.zip" -BinaryCache $BinaryCache -ExtractPath "android-ndk-$AndroidNDKVersion" -CreateExtractPath $false
-  }
+    if ($Android) {
+      $NDK = Get-AndroidNDK
+      DownloadAndVerify $NDK.URL "$BinaryCache\android-ndk-$AndroidNDKVersion-windows.zip" $NDK.SHA256
+      Expand-ZipFile -ZipFileName "android-ndk-$AndroidNDKVersion-windows.zip" -BinaryCache $BinaryCache -ExtractPath "android-ndk-$AndroidNDKVersion" -CreateExtractPath $false
+    }
 
-  if ($IncludeDS2) {
-    $WinFlexBisonVersion = "2.5.25"
-    $WinFlexBisonURL = "https://github.com/lexxmark/winflexbison/releases/download/v$WinFlexBisonVersion/win_flex_bison-$WinFlexBisonVersion.zip"
-    $WinFlexBisonHash = "8D324B62BE33604B2C45AD1DD34AB93D722534448F55A16CA7292DE32B6AC135"
-    DownloadAndVerify $WinFlexBisonURL "$BinaryCache\win_flex_bison-$WinFlexBisonVersion.zip" $WinFlexBisonHash
+    if ($IncludeDS2) {
+      $WinFlexBisonVersion = "2.5.25"
+      $WinFlexBisonURL = "https://github.com/lexxmark/winflexbison/releases/download/v$WinFlexBisonVersion/win_flex_bison-$WinFlexBisonVersion.zip"
+      $WinFlexBisonHash = "8D324B62BE33604B2C45AD1DD34AB93D722534448F55A16CA7292DE32B6AC135"
+      DownloadAndVerify $WinFlexBisonURL "$BinaryCache\win_flex_bison-$WinFlexBisonVersion.zip" $WinFlexBisonHash
 
-    Expand-ZipFile -ZipFileName "win_flex_bison-$WinFlexBisonVersion.zip" -BinaryCache $BinaryCache -ExtractPath "win_flex_bison"
-  }
+      Expand-ZipFile -ZipFileName "win_flex_bison-$WinFlexBisonVersion.zip" -BinaryCache $BinaryCache -ExtractPath "win_flex_bison"
+    }
 
-  if ($WinSDKVersion) {
-    try {
-      # Check whether VsDevShell can already resolve the requested Windows SDK Version
-      Invoke-IsolatingEnvVars { Invoke-VsDevShell $HostPlatform }
-    } catch {
-      $Package = Microsoft.Windows.SDK.CPP
+    if ($WinSDKVersion) {
+      try {
+        # Check whether VsDevShell can already resolve the requested Windows SDK Version
+        Invoke-IsolatingEnvVars { Invoke-VsDevShell $HostPlatform }
+      } catch {
+        $Package = Microsoft.Windows.SDK.CPP
 
-      Write-Output "Windows SDK $WinSDKVersion not found. Downloading from nuget.org ..."
-      Invoke-Program nuget install $Package -Version $WinSDKVersion -OutputDirectory $NugetRoot
+        Write-Output "Windows SDK $WinSDKVersion not found. Downloading from nuget.org ..."
+        Invoke-Program nuget install $Package -Version $WinSDKVersion -OutputDirectory $NugetRoot
 
-      # Set to script scope so Invoke-VsDevShell can read it.
-      $script:CustomWinSDKRoot = "$NugetRoot\$Package.$WinSDKVersion\c"
+        # Set to script scope so Invoke-VsDevShell can read it.
+        $script:CustomWinSDKRoot = "$NugetRoot\$Package.$WinSDKVersion\c"
 
-      # Install each required architecture package and move files under the base /lib directory.
-      $WinSDKPlatforms = $WindowsSDKPlatforms.Clone()
-      if (-not ($HostPlatform -in $WinSDKPlatforms)) {
-        $WinSDKPlatforms += $HostPlatform
-      }
+        # Install each required architecture package and move files under the base /lib directory.
+        $Builds = $WindowsSDKBuilds.Clone()
+        if (-not ($HostPlatform -in $Builds)) {
+          $Builds += $HostPlatform
+        }
 
-      foreach ($Platform in $WinSDKPlatforms) {
-        Invoke-Program nuget install $Package.$($Platform.Architecture.ShortName) -Version $WinSDKVersion -OutputDirectory $NugetRoot
-        Copy-Directory "$NugetRoot\$Package.$($Platform.Architecture.ShortName).$WinSDKVersion\c\*" "$CustomWinSDKRoot\lib\$WinSDKVersion"
+        foreach ($Build in $Builds) {
+          Invoke-Program nuget install $Package.$($Build.Architecture.ShortName) -Version $WinSDKVersion -OutputDirectory $NugetRoot
+          Copy-Directory "$NugetRoot\$Package.$($Build.Architecture.ShortName).$WinSDKVersion\c\*" "$CustomWinSDKRoot\lib\$WinSDKVersion"
+        }
       }
     }
-  }
 
-  if (-not $ToBatch) {
-    Write-Host -ForegroundColor Cyan "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Get-Dependencies took $($Stopwatch.Elapsed)"
-    Write-Host ""
-  }
-  if ($Summary) {
-    Add-TimingData $BuildPlatform "Get-Dependencies" $Stopwatch.Elapsed
+    if (-not $ToBatch) {
+      Write-Host -ForegroundColor Cyan "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Get-Dependencies took $($Stopwatch.Elapsed)"
+      Write-Host ""
+    }
   }
 }
 
 function Get-PinnedToolchainToolsDir() {
-  $ToolchainsRoot = [IO.Path]::Combine("$BinaryCache\toolchains", "$PinnedToolchain", "LocalApp", "Programs", "Swift", "Toolchains")
+  $ToolchainName = $PinnedToolchain.TrimStart("swift-").TrimEnd("-a-windows10")
+
+  $ToolchainsRoot = [IO.Path]::Combine("$BinaryCache\toolchains", "$ToolchainName", "LocalApp", "Programs", "Swift", "Toolchains")
 
   # NOTE: Add a workaround for the main snapshots that inadvertently used the
   # wrong version when they were built. This allows use of the nightly snapshot
@@ -1089,25 +1379,29 @@ function Get-PinnedToolchainToolsDir() {
     }
   }
 
-  $VariantToolchainPath = [IO.Path]::Combine($ToolchainsRoot, "$(Get-PinnedToolchainVersion)+$PinnedToolchainVariant", "usr", "bin")
+  $VariantToolchainPath = [IO.Path]::Combine($ToolchainsRoot, "$(Get-PinnedToolchainVersion)+Asserts", "usr", "bin")
 
   if (Test-Path $VariantToolchainPath) {
     return $VariantToolchainPath
   }
 
-  return [IO.Path]::Combine("$BinaryCache\", "toolchains", $PinnedToolchain,
+  return [IO.Path]::Combine("$BinaryCache\", "toolchains", $ToolchainName,
     "Library", "Developer", "Toolchains",
-    "unknown-$PinnedToolchainVariant-development.xctoolchain", "usr", "bin")
+    "unknown-Asserts-development.xctoolchain", "usr", "bin")
 }
 
-function Get-PinnedToolchainSDK() {
-  return [IO.Path]::Combine("$BinaryCache\", "toolchains", $PinnedToolchain,
+function Get-PinnedToolchainSDK([OS] $OS = $BuildPlatform.OS, [string] $Identifier = $OS.ToString()) {
+  $ToolchainName = $PinnedToolchain.TrimStart("swift-").TrimEnd("-a-windows10")
+
+  return [IO.Path]::Combine("$BinaryCache\", "toolchains", $ToolchainName,
     "LocalApp", "Programs", "Swift", "Platforms", (Get-PinnedToolchainVersion),
-    "Windows.platform", "Developer", "SDKs", "Windows.sdk")
+    "$($OS.ToString()).platform", "Developer", "SDKs", "$Identifier.sdk")
 }
 
 function Get-PinnedToolchainRuntime() {
-  return [IO.Path]::Combine("$BinaryCache\", "toolchains", $PinnedToolchain,
+  $ToolchainName = $PinnedToolchain.TrimStart("swift-").TrimEnd("-a-windows10")
+
+  return [IO.Path]::Combine("$BinaryCache\", "toolchains", $ToolchainName,
     "LocalApp", "Programs", "Swift", "Runtimes", (Get-PinnedToolchainVersion),
     "usr", "bin")
 }
@@ -1133,31 +1427,11 @@ function Add-FlagsDefine([hashtable]$Defines, [string]$Name, [string[]]$Value) {
   }
 }
 
-function Test-SCCacheAtLeast([int]$Major, [int]$Minor, [int]$Patch = 0) {
-  if ($ToBatch) { return $false }
-
-  $SCCacheVersionString = @(& sccache.exe --version)[0]
-  if (-not ($SCCacheVersionString -match "sccache (\d+)\.(\d+)(?:\.(\d+))?")) {
-    throw "Unexpected SCCache version string format"
-  }
-
-  if ([int]$Matches.1 -ne $Major) { return [int]$Matches.1 -gt $Major }
-  if ([int]$Matches.2 -ne $Minor) { return [int]$Matches.2 -gt $Minor }
-  if ($null -eq $Matches.3) { return 0 -gt $Patch }
-  return [int]$Matches.3 -ge $Patch
-}
-
 function Get-PlatformRoot([OS] $OS) {
   return ([IO.Path]::Combine((Get-InstallDir $HostPlatform), "Platforms", "$($OS.ToString()).platform"))
 }
 
-function Get-SwiftSDK {
-  param
-  (
-    [Parameter(Mandatory)]
-    [OS] $OS,
-    [string] $Identifier = $OS.ToString()
-  )
+function Get-SwiftSDK([OS] $OS, [string] $Identifier = $OS.ToString()) {
   return ([IO.Path]::Combine((Get-PlatformRoot $OS), "Developer", "SDKs", "$Identifier.sdk"))
 }
 
@@ -1171,257 +1445,386 @@ function Build-CMakeProject {
     [hashtable] $Platform,
     [string] $Generator = "Ninja",
     [string] $CacheScript = "",
-    [ValidateSet("C", "CXX")]
+    [ValidateSet("", "ASM_MASM", "C", "CXX")]
     [string[]] $UseMSVCCompilers = @(),
-    [ValidateSet("ASM", "C", "CXX", "Swift")]
+    [ValidateSet("", "ASM", "C", "CXX", "Swift")]
     [string[]] $UseBuiltCompilers = @(),
-    [ValidateSet("ASM", "C", "CXX", "Swift")]
+    [ValidateSet("", "ASM", "C", "CXX", "Swift")]
     [string[]] $UsePinnedCompilers = @(),
     [switch] $AddAndroidCMakeEnv = $false,
     [switch] $UseGNUDriver = $false,
-    [string] $SwiftSDK = "",
+    [string] $SwiftSDK = $null,
     [hashtable] $Defines = @{}, # Values are either single strings or arrays of flags
     [string[]] $BuildTargets = @()
   )
 
-  if ($ToBatch) {
-    Write-Output ""
-    Write-Output "echo Building '$Src' to '$Bin' ..."
-  } else {
-    Write-Host -ForegroundColor Cyan "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Building '$Src' to '$Bin' ..."
-  }
+  if ($ToBatch) {
+    Write-Output ""
+    Write-Output "echo Building '$Src' to '$Bin' ..."
+  } else {
+    Write-Host -ForegroundColor Cyan "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Building '$Src' to '$Bin' ..."
+  }
+
+  $Stopwatch = [Diagnostics.Stopwatch]::StartNew()
+
+  # Enter the developer command shell early so we can resolve cmake.exe
+  # for version checks.
+  Invoke-IsolatingEnvVars {
+    if ($Platform.OS -eq [OS]::Windows) {
+      Invoke-VsDevShell $Platform
+    }
+
+    if ($AddAndroidCMakeEnv) {
+      # Set generic android options if we need to build an Android runtime component
+      # while building the compiler. Use an environment variable to pass it, to
+      # ensure that it can be accessed from the cmake cache file.
+      $env:NDKPATH = Get-AndroidNDKPath
+    }
+
+    $UseASM = $UseBuiltCompilers.Contains("ASM") -or $UsePinnedCompilers.Contains("ASM")
+    $UseASM_MASM = $UseMSVCCompilers.Contains("ASM_MASM")
+    $UseC = $UseBuiltCompilers.Contains("C") -or $UseMSVCCompilers.Contains("C") -or $UsePinnedCompilers.Contains("C")
+    $UseCXX = $UseBuiltCompilers.Contains("CXX") -or $UseMSVCCompilers.Contains("CXX") -or $UsePinnedCompilers.Contains("CXX")
+    $UseSwift = $UseBuiltCompilers.Contains("Swift") -or $UsePinnedCompilers.Contains("Swift")
+
+    # Add additional defines (unless already present)
+    $Defines = $Defines.Clone()
+
+    Add-KeyValueIfNew $Defines CMAKE_BUILD_TYPE Release
+
+    # Avoid specifying `CMAKE_SYSTEM_NAME` and `CMAKE_SYSTEM_PROCESSOR` on
+    # Windows and in the case that we are not cross-compiling.
+    #
+    # TODO(etcwilde) consider removing this once we have removed
+    # SwiftSupport.cmake across the project.
+    if (($Platform.OS -ne [OS]::Windows) -or ($Platform.Architecture.CMakeName -ne $BuildPlatform.Architecture.CMakeName)) {
+      Add-KeyValueIfNew $Defines CMAKE_SYSTEM_NAME $Platform.OS.ToString()
+      Add-KeyValueIfNew $Defines CMAKE_SYSTEM_PROCESSOR $Platform.Architecture.CMakeName
+    }
+
+    # Always prefer the CONFIG format for the packages so that we can build
+    # against the build tree.
+    Add-KeyValueIfNew $Defines CMAKE_FIND_PACKAGE_PREFER_CONFIG YES
+
+    switch ($Platform.OS) {
+      Windows {
+        if ($UseASM) {
+          $Driver = $(if ($UseGNUDriver) { "clang.exe" } else { "clang-cl.exe" })
+          $ASM = if ($UseBuiltCompilers.Contains("ASM")) {
+            [IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", $Driver)
+          } elseif ($UsePinnedCompilers.Contains("ASM")) {
+            Join-Path -Path (Get-PinnedToolchainToolsDir) -ChildPath $Driver
+          }
+
+          Add-KeyValueIfNew $Defines CMAKE_ASM_COMPILER $ASM
+          Add-KeyValueIfNew $Defines CMAKE_ASM_FLAGS @("--target=$($Platform.Triple)")
+          Add-KeyValueIfNew $Defines CMAKE_ASM_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_MultiThreadedDLL "/MD"
+
+          if ($DebugInfo) {
+            $ASMDebugFlags = if ($CDebugFormat -eq "dwarf") {
+              if ($UseGNUDriver) { @("-gdwarf") } else { @("-clang:-gdwarf") }
+            } else {
+              if ($UseGNUDriver) { @("-gcodeview") } else { @("-clang:-gcodeview") }
+            }
+
+            # CMake does not set a default value for the ASM compiler debug
+            # information format flags with non-MSVC compilers, so we explicitly
+            # set a default here.
+            Add-FlagsDefine $Defines CMAKE_ASM_COMPILE_OPTIONS_MSVC_DEBUG_INFORMATION_FORMAT_Embedded $ASMDebugFlags
+          }
+        }
+
+        if ($UseASM_MASM) {
+          $ASM_MASM = if ($Platform.Architecture.VSName -eq "x86") {
+            "ml.exe"
+          } else {
+            "ml64.exe"
+          }
+
+          Add-KeyValueIfNew $Defines CMAKE_ASM_MASM_COMPILER $ASM_MASM
+          Add-KeyValueIfNew $Defines CMAKE_ASM_MASM_FLAGS @("/nologo" ,"/quiet")
+        }
+
+        if ($UseC) {
+          $CC = if ($UseMSVCCompilers.Contains("C")) {
+            "cl.exe"
+          } else {
+            $Driver = $(if ($UseGNUDriver) { "clang.exe" } else { "clang-cl.exe" })
+            if ($UseBuiltCompilers.Contains("C")) {
+              [IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", $Driver)
+            } elseif ($UsePinnedCompilers.Contains("C")) {
+              Join-Path -Path (Get-PinnedToolchainToolsDir) -ChildPath $Driver
+            }
+          }
+
+          Add-KeyValueIfNew $Defines CMAKE_C_COMPILER $CC
+          Add-KeyValueIfNew $Defines CMAKE_C_COMPILER_TARGET $Platform.Triple
+
+          $CFLAGS = if ($UseGNUDriver) {
+            # TODO(compnerd) we should consider enabling stack protector usage for standard libraries.
+            @("-fno-stack-protector", "-ffunction-sections", "-fdata-sections", "-fomit-frame-pointer")
+          } elseif ($UseMSVCCompilers.Contains("C")) {
+            @("/GS-", "/Gw", "/Gy", "/Oy", "/Oi", "/Zc:preprocessor", "/Zc:inline")
+          } else {
+            # clang-cl does not support the /Zc:preprocessor flag.
+            @("/GS-", "/Gw", "/Gy", "/Oy", "/Oi", "/Zc:inline")
+          }
+
+          if ($DebugInfo) {
+            if ($UsePinnedCompilers.Contains("C") -or $UseBuiltCompilers.Contains("C")) {
+              if ($CDebugFormat -eq "dwarf") {
+                $CFLAGS += if ($UseGNUDriver) {
+                  @("-gdwarf")
+                } else {
+                  @("-clang:-gdwarf")
+                }
+              }
+            }
+          }
+
+          Add-FlagsDefine $Defines CMAKE_C_FLAGS $CFLAGS
+        }
+
+        if ($UseCXX) {
+          $CXX = if ($UseMSVCCompilers.Contains("CXX")) {
+            "cl.exe"
+          } else {
+            $Driver = $(if ($UseGNUDriver) { "clang++.exe" } else { "clang-cl.exe" })
+            if ($UseBuiltCompilers.Contains("CXX")) {
+              [IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", $Driver)
+            } elseif ($UsePinnedCompilers.Contains("CXX")) {
+              Join-Path -Path (Get-PinnedToolchainToolsDir) -ChildPath $Driver
+            }
+          }
+
+          Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER $CXX
+          Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER_TARGET $Platform.Triple
+
+          $CXXFLAGS = if ($UseGNUDriver) {
+            # TODO(compnerd) we should consider enabling stack protector usage for standard libraries.
+            @("-fno-stack-protector", "-ffunction-sections", "-fdata-sections", "-fomit-frame-pointer")
+          } elseif ($UseMSVCCompilers.Contains("CXX")) {
+            @("/GS-", "/Gw", "/Gy", "/Oy", "/Oi", "/Zc:preprocessor", "/Zc:inline", "/Zc:__cplusplus")
+          } else {
+            # clang-cl does not support the /Zc:preprocessor flag.
+            @("/GS-", "/Gw", "/Gy", "/Oy", "/Oi", "/Zc:inline", "/Zc:__cplusplus")
+          }
+
+          if ($DebugInfo) {
+            if ($UsePinnedCompilers.Contains("CXX") -or $UseBuiltCompilers.Contains("CXX")) {
+              if ($CDebugFormat -eq "dwarf") {
+                $CXXFLAGS += if ($UseGNUDriver) {
+                  @("-gdwarf")
+                } else {
+                  @("-clang:-gdwarf")
+                }
+              }
+            }
+          }
+
+          Add-FlagsDefine $Defines CMAKE_CXX_FLAGS $CXXFLAGS
+        }
+
+        if ($UseSwift) {
+          if ($UseBuiltCompilers.Contains("Swift")) {
+            Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER_WORKS "YES"
+          }
+
+          $SWIFTC = if ($UseBuiltCompilers.Contains("Swift")) {
+            [IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", "swiftc.exe")
+          } elseif ($UsePinnedCompilers.Contains("Swift")) {
+            Join-Path -Path (Get-PinnedToolchainToolsDir) -ChildPath "swiftc.exe"
+          }
 
-  $Stopwatch = [Diagnostics.Stopwatch]::StartNew()
+          Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER $SWIFTC
+          Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER_TARGET (Get-ModuleTriple $Platform)
 
-  # Enter the developer command shell early so we can resolve cmake.exe
-  # for version checks.
-  Invoke-IsolatingEnvVars {
-    if ($Platform.OS -eq [OS]::Windows) {
-      Invoke-VsDevShell $Platform
-    }
+          # TODO(compnerd): remove this once we have the early swift-driver
+          Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER_USE_OLD_DRIVER "YES"
 
-    # Add additional defines (unless already present)
-    $Defines = $Defines.Clone()
+          [string[]] $SwiftFlags = @();
 
-    if (($Platform.OS -ne [OS]::Windows) -or ($Platform.Architecture.CMakeName -ne $BuildPlatform.Architecture.CMakeName)) {
-      Add-KeyValueIfNew $Defines CMAKE_SYSTEM_NAME $Platform.OS.ToString()
-      Add-KeyValueIfNew $Defines CMAKE_SYSTEM_PROCESSOR $Platform.Architecture.CMakeName
-    }
+          $SwiftFlags += if ($SwiftSDK) {
+            @("-sdk", $SwiftSDK)
+          } else {
+            @()
+          }
 
-    if ($AddAndroidCMakeEnv) {
-      # Set generic android options if we need to build an Android runtime component
-      # while building the compiler. Use an environment variable to pass it, to
-      # ensure that it can be accessed from the cmake cache file.
-      $env:NDKPATH = Get-AndroidNDKPath
-    }
+          $SwiftFlags += if ($DebugInfo) {
+            if ($SwiftDebugFormat -eq "dwarf") {
+              @("-g", "-debug-info-format=dwarf", "-use-ld=lld-link", "-Xlinker", "/DEBUG:DWARF")
+            } else {
+              @("-g", "-debug-info-format=codeview", "-Xlinker", "/DEBUG")
+            }
+          } else {
+            @("-gnone")
+          }
 
-    if ($Platform.OS -eq [OS]::Android) {
-      $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
-      $VSInstallPath = & $vswhere -nologo -latest -products * -property installationPath
-      if (Test-Path "${VSInstallPath}\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin") {
-        $env:Path = "${VSInstallPath}\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin;${VSInstallPath}\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja;${env:Path}"
-        Add-KeyValueIfNew $Defines CMAKE_MAKE_PROGRAM "${VSInstallPath}\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja\ninja.exe"
-      } else {
-        throw "Missing CMake and Ninja in the visual studio installation that are needed to build Android"
-      }
-      $androidNDKPath = Get-AndroidNDKPath
-      Add-KeyValueIfNew $Defines CMAKE_C_COMPILER (Join-Path -Path $androidNDKPath -ChildPath "toolchains\llvm\prebuilt\windows-x86_64\bin\clang.exe")
-      Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER (Join-Path -Path $androidNDKPath -ChildPath "toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe")
-      Add-KeyValueIfNew $Defines CMAKE_ANDROID_API "$AndroidAPILevel"
-      Add-KeyValueIfNew $Defines CMAKE_ANDROID_ARCH_ABI $Platform.Architecture.ABI
-      Add-KeyValueIfNew $Defines CMAKE_ANDROID_NDK "$androidNDKPath"
-      Add-KeyValueIfNew $Defines SWIFT_ANDROID_NDK_PATH "$androidNDKPath"
-      Add-KeyValueIfNew $Defines CMAKE_C_COMPILER_WORKS YES
-      Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER_WORKS YES
-    }
+          # Disable EnC as that introduces padding in the conformance tables
+          $SwiftFlags += @("-Xlinker", "/INCREMENTAL:NO")
+          # Swift requires COMDAT folding and de-duplication
+          $SwiftFlags += @("-Xlinker", "/OPT:REF", "-Xlinker", "/OPT:ICF")
 
-    Add-KeyValueIfNew $Defines CMAKE_BUILD_TYPE Release
+          Add-FlagsDefine $Defines CMAKE_Swift_FLAGS $SwiftFlags
+          # Workaround CMake 3.26+ enabling `-wmo` by default on release builds
+          Add-FlagsDefine $Defines CMAKE_Swift_FLAGS_RELEASE "-O"
+          Add-FlagsDefine $Defines CMAKE_Swift_FLAGS_RELWITHDEBINFO "-O"
+        }
 
-    $CFlags = @()
-    switch ($Platform.OS) {
-      Windows {
-        $CFlags = if ($UseGNUDriver) {
-          @("-fno-stack-protector", "-ffunction-sections", "-fdata-sections", "-fomit-frame-pointer")
+        $LinkerFlags = if ($UseGNUDriver) {
+          @("-Xlinker", "/INCREMENTAL:NO", "-Xlinker", "/OPT:REF", "-Xlinker", "/OPT:ICF")
         } else {
-          @("/GS-", "/Gw", "/Gy", "/Oi", "/Oy", "/Zc:inline")
+          @("/INCREMENTAL:NO", "/OPT:REF", "/OPT:ICF")
         }
-      }
-      Android {
-        $CFlags = @("--sysroot=$(Get-AndroidNDKPath)\toolchains\llvm\prebuilt\windows-x86_64\sysroot")
-      }
-    }
 
-    $CXXFlags = @()
-    if ($Platform.OS -eq [OS]::Windows -and -not $UseGNUDriver) {
-      $CXXFlags += $CFlags.Clone() + @("/Zc:__cplusplus")
-    }
+        if ($DebugInfo) {
+          if ($UseASM -or $UseC -or $UseCXX) {
+            # Prefer `/Z7` over `/ZI`
+            # By setting the debug information format, the appropriate C/C++
+            # flags will be set for codeview debug information format so there
+            # is no need to set them explicitly above.
+            Add-KeyValueIfNew $Defines CMAKE_MSVC_DEBUG_INFORMATION_FORMAT Embedded
+            Add-KeyValueIfNew $Defines CMAKE_POLICY_DEFAULT_CMP0141 NEW
+
+            $LinkerFlags += if ($UseGNUDriver) {
+              @("-Xlinker", "/DEBUG")
+            } else {
+              @("/DEBUG")
+            }
 
-    if ($UseMSVCCompilers.Contains("C") -Or $UseMSVCCompilers.Contains("CXX") -Or
-        $UseBuiltCompilers.Contains("C") -Or $UseBuiltCompilers.Contains("CXX") -Or
-        $UsePinnedCompilers.Contains("C") -Or $UsePinnedCompilers.Contains("CXX")) {
-      if ($DebugInfo -and $Platform.OS -eq [OS]::Windows) {
-        Add-FlagsDefine $Defines CMAKE_MSVC_DEBUG_INFORMATION_FORMAT Embedded
-        Add-FlagsDefine $Defines CMAKE_POLICY_CMP0141 NEW
-        # Add additional linker flags for generating the debug info.
-        if ($UseGNUDriver) {
-          Add-FlagsDefine $Defines CMAKE_SHARED_LINKER_FLAGS @("-Xlinker", "-debug")
-          Add-FlagsDefine $Defines CMAKE_EXE_LINKER_FLAGS @("-Xlinker", "-debug")
-        } else {
-          Add-FlagsDefine $Defines CMAKE_SHARED_LINKER_FLAGS "/debug"
-          Add-FlagsDefine $Defines CMAKE_EXE_LINKER_FLAGS "/debug"
+            # The linker flags are shared across every language, and `/IGNORE:longsections` is an
+            # `lld-link.exe` argument, not `link.exe`, so this can only be enabled when we use
+            # `lld-link.exe` for linking.
+            # TODO: Investigate supporting fission with PE/COFF, this should avoid this warning.
+            if ($SwiftDebugFormat -eq "dwarf") {
+              if ($UseGNUDriver) {
+                $LinkerFlags += @("-Xlinker", "/IGNORE:longsections")
+              } elseif (-not $UseMSVCCompilers.Contains("C") -and -not $UseMSVCCompilers.Contains("CXX")) {
+                $LinkerFlags += @("/IGNORE:longsections")
+              }
+            }
+          }
         }
-      } elseif ($Platform.OS -eq [OS]::Android) {
-        # Use a built lld linker as the Android's NDK linker might be too
-        # old and not support all required relocations needed by the Swift
-        # runtime.
-        $ldPath = ([IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", "ld.lld"))
-        Add-FlagsDefine $Defines CMAKE_SHARED_LINKER_FLAGS "--ld-path=$ldPath"
-        Add-FlagsDefine $Defines CMAKE_EXE_LINKER_FLAGS "--ld-path=$ldPath"
-      }
-    }
 
-    if ($UseMSVCCompilers.Contains("C")) {
-      Add-KeyValueIfNew $Defines CMAKE_C_COMPILER cl
-      if ($EnableCaching) {
-        Add-KeyValueIfNew $Defines CMAKE_C_COMPILER_LAUNCHER sccache
-      }
-      Add-FlagsDefine $Defines CMAKE_C_FLAGS $CFlags
-    }
-    if ($UseMSVCCompilers.Contains("CXX")) {
-      Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER cl
-      if ($EnableCaching) {
-        Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER_LAUNCHER sccache
-      }
-      Add-FlagsDefine $Defines CMAKE_CXX_FLAGS $CXXFlags
-    }
-    if ($UsePinnedCompilers.Contains("ASM") -Or $UseBuiltCompilers.Contains("ASM")) {
-      $Driver = if ($Platform.OS -eq [OS]::Windows) { "clang-cl.exe" } else { "clang.exe" }
-      if ($UseBuiltCompilers.Contains("ASM")) {
-        Add-KeyValueIfNew $Defines CMAKE_ASM_COMPILER ([IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", $Driver))
-      } else {
-        Add-KeyValueIfNew $Defines CMAKE_ASM_COMPILER (Join-Path -Path (Get-PinnedToolchainToolsDir) -ChildPath $Driver)
+        Add-FlagsDefine $Defines CMAKE_EXE_LINKER_FLAGS $LinkerFlags
+        Add-FlagsDefine $Defines CMAKE_SHARED_LINKER_FLAGS $LinkerFlags
       }
-      Add-FlagsDefine $Defines CMAKE_ASM_FLAGS "--target=$($Platform.Triple)"
-      if ($Platform.OS -eq [OS]::Windows) {
-        Add-KeyValueIfNew $Defines CMAKE_ASM_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_MultiThreadedDLL "/MD"
-      }
-    }
-    if ($UsePinnedCompilers.Contains("C") -Or $UseBuiltCompilers.Contains("C")) {
-      $Driver = if ($Platform.OS -eq [OS]::Windows -and -not $UseGNUDriver) { "clang-cl.exe" } else { "clang.exe" }
-      if ($UseBuiltCompilers.Contains("C")) {
-        Add-KeyValueIfNew $Defines CMAKE_C_COMPILER ([IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", $Driver))
-      } else {
-        Add-KeyValueIfNew $Defines CMAKE_C_COMPILER (Join-Path -Path (Get-PinnedToolchainToolsDir) -ChildPath $Driver)
-      }
-      Add-KeyValueIfNew $Defines CMAKE_C_COMPILER_TARGET $Platform.Triple
 
-      if ($DebugInfo -and $CDebugFormat -eq "dwarf") {
-        Add-FlagsDefine $Defines CMAKE_C_FLAGS "-gdwarf"
-      }
-      Add-FlagsDefine $Defines CMAKE_C_FLAGS $CFlags
-    }
-    if ($UsePinnedCompilers.Contains("CXX") -Or $UseBuiltCompilers.Contains("CXX")) {
-      $Driver = if ($Platform.OS -eq [OS]::Windows -and -not $UseGNUDriver) { "clang-cl.exe" } else { "clang++.exe" }
-      if ($UseBuiltCompilers.Contains("CXX")) {
-        Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER ([IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", $Driver))
-      } else {
-        Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER (Join-Path -Path (Get-PinnedToolchainToolsDir) -ChildPath $Driver)
-      }
-      Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER_TARGET $Platform.Triple
+      Android {
+        $AndroidNDKPath = Get-AndroidNDKPath
+        $AndroidPrebuiltRoot = "$AndroidNDKPath\toolchains\llvm\prebuilt\$($BuildPlatform.OS.ToString().ToLowerInvariant())-$($BuildPlatform.Architecture.LLVMName)"
+        $AndroidSysroot = "$AndroidPrebuiltRoot\sysroot"
 
-      if ($DebugInfo -and $CDebugFormat -eq "dwarf") {
-        Add-FlagsDefine $Defines CMAKE_CXX_FLAGS "-gdwarf"
-      }
-      Add-FlagsDefine $Defines CMAKE_CXX_FLAGS $CXXFlags
-    }
-    if ($UsePinnedCompilers.Contains("Swift") -Or $UseBuiltCompilers.Contains("Swift")) {
-      $SwiftArgs = @()
+        Add-KeyValueIfNew $Defines CMAKE_ANDROID_API "$AndroidAPILevel"
+        Add-KeyValueIfNew $Defines CMAKE_ANDROID_ARCH_ABI $Platform.Architecture.ABI
+        Add-KeyValueIfNew $Defines CMAKE_ANDROID_NDK "$AndroidNDKPath"
 
-      if ($UseBuiltCompilers.Contains("Swift")) {
-        Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER ([IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", "swiftc.exe"))
-      } else {
-        Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER (Join-Path -Path (Get-PinnedToolchainToolsDir) -ChildPath  "swiftc.exe")
-      }
-      if (-not ($Platform.OS -eq [OS]::Windows)) {
-        Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER_WORKS = "YES"
-      }
-      if ($UseBuiltCompilers.Contains("Swift")) {
-        Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER_TARGET (Get-ModuleTriple $Platform)
-        $RuntimeBinaryCache = Get-ProjectBinaryCache $BuildPlatform Runtime
-        $SwiftResourceDir = "${RuntimeBinaryCache}\lib\swift"
-
-        switch ($Platform.OS) {
-          Windows {
-            if ($SwiftSDK -ne "") {
-              $SwiftArgs += @("-sdk", $SwiftSDK)
-            } else {
-              $SwiftArgs += @(
-                "-vfsoverlay", "$RuntimeBinaryCache\stdlib\windows-vfs-overlay.yaml",
-                "-strict-implicit-module-context",
-                "-Xcc", "-Xclang", "-Xcc", "-fbuiltin-headers-in-system-modules"
-              )
-              $SwiftArgs += @("-resource-dir", "$SwiftResourceDir")
-              $SwiftArgs += @("-L", "$SwiftResourceDir\$($_.ToString().ToLowerInvariant())")
-            }
+        if ($UseASM) {
+        }
+
+        if ($UseC) {
+          Add-KeyValueIfNew $Defines CMAKE_C_COMPILER_TARGET $Platform.Triple
+
+          $CFLAGS = @("--sysroot=${AndroidSysroot}", "-ffunction-sections", "-fdata-sections")
+          if ($DebugInfo) {
+            $CFLAGS += @("-gdwarf")
           }
-          Android {
-            $AndroidNDKPath = Get-AndroidNDKPath
-            if ($SwiftSDK -ne "") {
-              $SwiftArgs += @("-sdk", $SwiftSDK)
-              $SwiftArgs += @("-sysroot", "$AndroidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\sysroot")
-            } else {
-              $SwiftArgs += @("-sdk", "$AndroidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\sysroot")
-              $SwiftArgs += @("-resource-dir", "$SwiftResourceDir")
-              $SwiftArgs += @("-L", "$SwiftResourceDir\$($_.ToString().ToLowerInvariant())")
-            }
-            $SwiftArgs += @(
-              "-Xclang-linker", "-target",
-              "-Xclang-linker", $Platform.Triple,
-              "-Xclang-linker", "--sysroot",
-              "-Xclang-linker", "$AndroidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\sysroot",
-              "-Xclang-linker", "-resource-dir",
-              "-Xclang-linker", "$AndroidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\lib\clang\$($(Get-AndroidNDK).ClangVersion)"
-            )
+          Add-FlagsDefine $Defines CMAKE_C_FLAGS $CFLAGS
+        }
+
+        if ($UseCXX) {
+          Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER_TARGET $Platform.Triple
+
+          $CXXFLAGS = @("--sysroot=${AndroidSysroot}", "-ffunction-sections", "-fdata-sections")
+          if ($DebugInfo) {
+            $CXXFLAGS += @("-gdwarf")
           }
+          Add-FlagsDefine $Defines CMAKE_CXX_FLAGS $CXXFLAGS
         }
 
-      } else {
-        Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER_TARGET $Platform.Triple
-        $SwiftArgs += @("-sdk", (Get-PinnedToolchainSDK))
-      }
+        if ($UseSwift) {
+          if ($UseBuiltCompilers.Contains("Swift")) {
+            Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER_WORKS "YES"
+          }
+
+          # FIXME(compnerd) remove this once the old runtimes build path is removed.
+          Add-KeyValueIfNew $Defines SWIFT_ANDROID_NDK_PATH "$AndroidNDKPath"
 
-      # Debug Information
-      if ($DebugInfo) {
-        if ($Platform.OS -eq [OS]::Windows) {
-          if ($SwiftDebugFormat -eq "dwarf") {
-            $SwiftArgs += @("-g", "-Xlinker", "/DEBUG:DWARF", "-use-ld=lld-link")
+          $SWIFTC = if ($UseBuiltCompilers.Contains("Swift")) {
+            [IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", "swiftc.exe")
           } else {
-            $SwiftArgs += @("-g", "-debug-info-format=codeview", "-Xlinker", "-debug")
+            Join-Path -Path (Get-PinnedToolchainToolsDir) -ChildPath  "swiftc.exe"
           }
-        } else {
-          $SwiftArgs += @("-g")
+          Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER $SWIFTC
+          Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER_TARGET (Get-ModuleTriple $Platform)
+
+          # TODO(compnerd) remove this once we have the early swift-driver
+          Add-KeyValueIfNew $Defines CMAKE_Swift_COMPILER_USE_OLD_DRIVER "YES"
+
+          [string[]] $SwiftFlags = @()
+
+          $SwiftFlags += if ($SwiftSDK) {
+            @("-sdk", $SwiftSDK, "-sysroot", $AndroidSysroot)
+          } else {
+            @()
+          }
+
+          $SwiftFlags += @(
+            "-Xclang-linker", "-target", "-Xclang-linker", $Platform.Triple,
+            "-Xclang-linker", "--sysroot", "-Xclang-linker", $AndroidSysroot,
+            "-Xclang-linker", "-resource-dir", "-Xclang-linker", "${AndroidPrebuiltRoot}\lib\clang\$($(Get-AndroidNDK).ClangVersion)"
+          )
+
+          # FIXME(compnerd) remove this once we have the early swift-driver
+          if ($SwiftSDK) {
+            $SwiftFlags += @("-Xclang-linker", "-L", "-Xclang-linker", [IO.Path]::Combine($SwiftSDK, "usr", "lib", "swift", "android", $Platform.Architecture.LLVMName))
+          }
+
+          $SwiftFlags += if ($DebugInfo) { @("-g") } else { @("-gnone") }
+
+          Add-FlagsDefine $Defines CMAKE_Swift_FLAGS $SwiftFlags
+          # Workaround CMake 3.26+ enabling `-wmo` by default on release builds
+          Add-FlagsDefine $Defines CMAKE_Swift_FLAGS_RELEASE "-O"
+          Add-FlagsDefine $Defines CMAKE_Swift_FLAGS_RELWITHDEBINFO "-O"
+        }
+
+        $UseBuiltASMCompiler = $UseBuiltCompilers.Contains("ASM")
+        $UseBuiltCCompiler = $UseBuiltCompilers.Contains("C")
+        $UseBuiltCXXCompiler = $UseBuiltCompilers.Contains("CXX")
+
+        if ($UseBuiltASMCompiler -or $UseBuiltCCompiler -or $UseBuiltCXXCompiler) {
+          # Use a built lld linker as the Android's NDK linker might be too old
+          # and not support all required relocations needed by the Swift
+          # runtime.
+          $ld = ([IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin", "ld.lld"))
+          Add-FlagsDefine $Defines CMAKE_SHARED_LINKER_FLAGS "--ld-path=$ld"
+          Add-FlagsDefine $Defines CMAKE_EXE_LINKER_FLAGS "--ld-path=$ld"
         }
-      } else {
-        $SwiftArgs += "-gnone"
-      }
 
-      if ($Platform.OS -eq [OS]::Windows) {
-        $SwiftArgs += @("-Xlinker", "/INCREMENTAL:NO")
-        # Swift requires COMDAT folding and de-duplication
-        $SwiftArgs += @("-Xlinker", "/OPT:REF")
-        $SwiftArgs += @("-Xlinker", "/OPT:ICF")
+        # TODO(compnerd) we should understand why CMake does not understand
+        # that the object file format is ELF when targeting Android on Windows.
+        # This indication allows it to understand that it can use `chrpath` to
+        # change the RPATH on the dynamic libraries.
+        Add-FlagsDefine $Defines CMAKE_EXECUTABLE_FORMAT "ELF"
       }
+    }
 
-      Add-FlagsDefine $Defines CMAKE_Swift_FLAGS $SwiftArgs
+    if ($EnableCaching) {
+      if ($UseC) {
+        Add-KeyValueIfNew $Defines CMAKE_C_COMPILER_LAUNCHER $(Get-SCCache).Path
+      }
 
-      # Workaround CMake 3.26+ enabling `-wmo` by default on release builds
-      Add-FlagsDefine $Defines CMAKE_Swift_FLAGS_RELEASE "-O"
-      Add-FlagsDefine $Defines CMAKE_Swift_FLAGS_RELWITHDEBINFO "-O"
+      if ($UseCXX) {
+        Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER_LAUNCHER $(Get-SCCache).Path
+      }
     }
+
     if ($InstallTo) {
       Add-KeyValueIfNew $Defines CMAKE_INSTALL_PREFIX $InstallTo
     }
 
+    Add-KeyValueIfNew $Defines CMAKE_MAKE_PROGRAM "$ninja"
+
     # Generate the project
     $cmakeGenerateArgs = @("-B", $Bin, "-S", $Src, "-G", $Generator)
     if ($CacheScript) {
@@ -1445,8 +1848,10 @@ function Build-CMakeProject {
 
           $ArgWithForwardSlashes = $Arg.Replace("\", "/")
           if ($ArgWithForwardSlashes.Contains(" ")) {
-            # Quote and escape the quote so it makes it through
-            $Value += "\""$ArgWithForwardSlashes\"""
+            # Escape the quote so it makes it through. PowerShell 5 and Core
+            # handle quotes differently, so we need to check the version.
+            $quote = if ($PSEdition  -eq "Core") { '"' } else { '\"' }
+            $Value += "$quote$ArgWithForwardSlashes$quote"
           } else {
             $Value += $ArgWithForwardSlashes
           }
@@ -1461,26 +1866,25 @@ function Build-CMakeProject {
     } elseif ($UsePinnedCompilers.Contains("Swift")) {
       $env:Path = "$(Get-PinnedToolchainRuntime);${env:Path}"
     }
-
     if ($ToBatch) {
       Write-Output ""
-      Write-Output "echo cmake.exe $cmakeGenerateArgs"
+      Write-Output "echo $cmake $cmakeGenerateArgs"
     } else {
-      Write-Host "cmake.exe $cmakeGenerateArgs"
+      Write-Host "$cmake $cmakeGenerateArgs"
     }
-    Invoke-Program cmake.exe @cmakeGenerateArgs
+    Invoke-Program $cmake @cmakeGenerateArgs
 
     # Build all requested targets
     foreach ($Target in $BuildTargets) {
       if ($Target -eq "default") {
-        Invoke-Program cmake.exe --build $Bin
+        Invoke-Program $cmake --build $Bin
       } else {
-        Invoke-Program cmake.exe --build $Bin --target $Target
+        Invoke-Program $cmake --build $Bin --target $Target
       }
     }
 
     if ($BuildTargets.Length -eq 0 -and $InstallTo) {
-      Invoke-Program cmake.exe --build $Bin --target install
+      Invoke-Program $cmake --build $Bin --target install
     }
   }
 
@@ -1528,26 +1932,22 @@ function Build-SPMProject {
   $Stopwatch = [Diagnostics.Stopwatch]::StartNew()
 
   Invoke-IsolatingEnvVars {
-    $RuntimeInstallRoot = [IO.Path]::Combine((Get-InstallDir $HostPlatform), "Runtimes", $ProductVersion)
+    $RuntimeInstallRoot = [IO.Path]::Combine((Get-InstallDir $BuildPlatform), "Runtimes", $ProductVersion)
 
-    $env:Path = "$RuntimeInstallRoot\usr\bin;$($HostPlatform.ToolchainInstallRoot)\usr\bin;${env:Path}"
-    $env:SDKROOT = (Get-SwiftSDK Windows)
+    $env:Path = "$RuntimeInstallRoot\usr\bin;$($BuildPlatform.ToolchainInstallRoot)\usr\bin;${env:Path}"
+    $env:SDKROOT = (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK)
     $env:SWIFTCI_USE_LOCAL_DEPS = "1"
 
     $Arguments = @(
-        "--scratch-path", $Bin,
-        "--package-path", $Src,
-        "-c", $Configuration,
-        "-Xbuild-tools-swiftc", "-I$(Get-SwiftSDK Windows)\usr\lib\swift",
-        "-Xbuild-tools-swiftc", "-L$(Get-SwiftSDK Windows)\usr\lib\swift\windows",
-        "-Xcc", "-I$(Get-SwiftSDK Windows)\usr\lib\swift",
-        "-Xlinker", "-L$(Get-SwiftSDK Windows)\usr\lib\swift\windows"
+      "--scratch-path", $Bin,
+      "--package-path", $Src,
+      "-c", $Configuration
     )
     if ($DebugInfo) {
-      if ($SwiftDebugFormat -eq "dwarf") {
-        $Arguments += @("-debug-info-format", "dwarf")
-      } else {
+      if ($Platform.OS -eq [OS]::Windows -and $SwiftDebugFormat -eq "codeview") {
         $Arguments += @("-debug-info-format", "codeview")
+      } else {
+        $Arguments += @("-debug-info-format", "dwarf")
       }
     } else {
       $Arguments += @("-debug-info-format", "none")
@@ -1566,7 +1966,7 @@ function Build-SPMProject {
       }
     }
 
-    Invoke-Program "$($HostPlatform.ToolchainInstallRoot)\usr\bin\swift.exe" $ActionName @Arguments @AdditionalArguments
+    Invoke-Program swift $ActionName @Arguments @AdditionalArguments
   }
 
   if (-not $ToBatch) {
@@ -1601,12 +2001,9 @@ function Build-WiXProject() {
   Add-KeyValueIfNew $Properties ProductArchitecture $Platform.Architecture.VSName
   Add-KeyValueIfNew $Properties ProductVersion $ProductVersionArg
 
-  $MSBuildArgs = @("$SourceCache\swift-installer-scripts\platforms\Windows\$FileName")
-  $MSBuildArgs += "-noLogo"
-  $MSBuildArgs += "-restore"
-  $MSBuildArgs += "-maxCpuCount"
+  $MSBuildArgs = @( "-noLogo", "-maxCpuCount", "-restore", "$SourceCache\swift-installer-scripts\platforms\Windows\$FileName" )
   foreach ($Property in $Properties.GetEnumerator()) {
-    if ($Property.Value.Contains(" ")) {
+    if ($Property.Value -is [string] -and $Property.Value.Contains(" ")) {
       $MSBuildArgs += "-p:$($Property.Key)=$($Property.Value.Replace('\', '\\'))"
     } else {
       $MSBuildArgs += "-p:$($Property.Key)=$($Property.Value)"
@@ -1627,8 +2024,10 @@ function Build-CMark([Hashtable] $Platform) {
   Build-CMakeProject `
     -Src $SourceCache\cmark `
     -Bin (Get-CMarkBinaryCache $Platform) `
-    -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
+    -InstallTo "$(Get-InstallDir $Platform)\Toolchains\$ProductVersion+Asserts\usr" `
     -Platform $Platform `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("C", "CXX") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("C", "CXX") }) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
       BUILD_TESTING = "NO";
@@ -1641,8 +2040,9 @@ function Build-BuildTools([Hashtable] $Platform) {
     -Src $SourceCache\llvm-project\llvm `
     -Bin (Get-ProjectBinaryCache $Platform BuildTools) `
     -Platform $Platform `
-    -UseMSVCCompilers C,CXX `
-    -BuildTargets llvm-tblgen,clang-tblgen,clang-pseudo-gen,clang-tidy-confusable-chars-gen,lldb-tblgen,llvm-config,swift-def-to-strings-converter,swift-serialize-diagnostics,swift-compatibility-symbols `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("ASM_MASM", "C", "CXX") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("ASM", "C", "CXX") }) `
+    -BuildTargets llvm-tblgen,clang-tblgen,clang-tidy-confusable-chars-gen,lldb-tblgen,llvm-config,swift-def-to-strings-converter,swift-serialize-diagnostics,swift-compatibility-symbols `
     -Defines @{
       CMAKE_CROSSCOMPILING = "NO";
       CLANG_ENABLE_LIBXML2 = "NO";
@@ -1670,7 +2070,7 @@ function Build-BuildTools([Hashtable] $Platform) {
       SWIFT_INCLUDE_APINOTES = "NO";
       SWIFT_INCLUDE_DOCS = "NO";
       SWIFT_INCLUDE_TESTS = "NO";
-      "cmark-gfm_DIR" = "$($Platform.ToolchainInstallRoot)\usr\lib\cmake";
+      "cmark-gfm_DIR" = "$(Get-InstallDir $Platform)\Toolchains\$ProductVersion+Asserts\usr\lib\cmake";
     }
 }
 
@@ -1706,7 +2106,21 @@ function Load-LitTestOverrides($Filename) {
   }
 }
 
-function Get-CompilersDefines([Hashtable] $Platform, [switch] $Test) {
+function Build-CDispatch([Hashtable] $Platform, [switch] $Static = $false) {
+  Build-CMakeProject `
+    -Src $SourceCache\swift-corelibs-libdispatch `
+    -Bin (Get-ProjectBinaryCache $Platform CDispatch) `
+    -BuildTargets default `
+    -Platform $Platform `
+    -UsePinnedCompilers C,CXX `
+    -Defines @{
+      BUILD_SHARED_LIBS = "YES";
+      BUILD_TESTING = "NO";
+      ENABLE_SWIFT = "NO";
+    }
+}
+
+function Get-CompilersDefines([Hashtable] $Platform, [string] $Variant, [switch] $Test) {
   $BuildTools = [IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform BuildTools), "bin")
   $PythonRoot = [IO.Path]::Combine((Get-PythonPath $Platform), "tools")
   $PythonLibName = "python{0}{1}" -f ([System.Version]$PythonVersion).Major, ([System.Version]$PythonVersion).Minor
@@ -1739,12 +2153,16 @@ function Get-CompilersDefines([Hashtable] $Platform, [switch] $Test) {
     $SwiftFlags += @("-Xcc", "-D_ALLOW_COMPILER_AND_STL_VERSION_MISMATCH");
   }
 
+  if ($LTO -ne "none") {
+    $SwiftFlags += @("-use-ld=lld");
+  }
+
   return $TestDefines + $DebugDefines + @{
     CLANG_TABLEGEN = (Join-Path -Path $BuildTools -ChildPath "clang-tblgen.exe");
     CLANG_TIDY_CONFUSABLE_CHARS_GEN = (Join-Path -Path $BuildTools -ChildPath "clang-tidy-confusable-chars-gen.exe");
-    CMAKE_FIND_PACKAGE_PREFER_CONFIG = "YES";
     CMAKE_Swift_FLAGS = $SwiftFlags;
-    LibXml2_DIR = "$LibraryRoot\libxml2-2.11.5\usr\lib\Windows\$($Platform.Architecture.LLVMName)\cmake\libxml2-2.11.5";
+    LibXml2_DIR = "$BinaryCache\$($Platform.Triple)\usr\lib\cmake\libxml2-2.11.5";
+    LLDB_LIBXML2_VERSION = "2.11.5";
     LLDB_PYTHON_EXE_RELATIVE_PATH = "python.exe";
     LLDB_PYTHON_EXT_SUFFIX = ".pyd";
     LLDB_PYTHON_RELATIVE_PATH = "lib/site-packages";
@@ -1752,8 +2170,19 @@ function Get-CompilersDefines([Hashtable] $Platform, [switch] $Test) {
     LLDB_TEST_MAKE = "$BinaryCache\GnuWin32Make-4.4.1\bin\make.exe";
     LLVM_CONFIG_PATH = (Join-Path -Path $BuildTools -ChildPath "llvm-config.exe");
     LLVM_ENABLE_ASSERTIONS = $(if ($Variant -eq "Asserts") { "YES" } else { "NO" })
+    LLVM_ENABLE_LTO = $(switch ($LTO) {
+      "none" { "OFF" }
+      default {
+        if ($UseHostToolchain) { throw "LTO is not supported with the host toolchain" }
+        "$LTO"
+      }
+    })
+    LLVM_ENABLE_LLD = $(switch ($LTO) {
+      "none" { "NO" }
+      default { "YES" }
+    })
     LLVM_EXTERNAL_SWIFT_SOURCE_DIR = "$SourceCache\swift";
-    LLVM_HOST_TRIPLE = $BuildPlatform.Triple;
+    LLVM_HOST_TRIPLE = $Platform.Triple;
     LLVM_NATIVE_TOOL_DIR = $BuildTools;
     LLVM_TABLEGEN = (Join-Path $BuildTools -ChildPath "llvm-tblgen.exe");
     LLVM_USE_HOST_TOOLS = "NO";
@@ -1761,6 +2190,7 @@ function Get-CompilersDefines([Hashtable] $Platform, [switch] $Test) {
     Python3_INCLUDE_DIR = "$PythonRoot\include";
     Python3_LIBRARY = "$PythonRoot\libs\$PythonLibName.lib";
     Python3_ROOT_DIR = $PythonRoot;
+    SWIFT_TOOLCHAIN_VERSION = "${ToolchainIdentifier}";
     SWIFT_BUILD_SWIFT_SYNTAX = "YES";
     SWIFT_CLANG_LOCATION = (Get-PinnedToolchainToolsDir);
     SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY = "YES";
@@ -1773,7 +2203,7 @@ function Get-CompilersDefines([Hashtable] $Platform, [switch] $Test) {
     SWIFT_ENABLE_VOLATILE = "YES";
     SWIFT_PATH_TO_LIBDISPATCH_SOURCE = "$SourceCache\swift-corelibs-libdispatch";
     SWIFT_PATH_TO_STRING_PROCESSING_SOURCE = "$SourceCache\swift-experimental-string-processing";
-    SWIFT_PATH_TO_SWIFT_SDK = (Get-PinnedToolchainSDK);
+    SWIFT_PATH_TO_SWIFT_SDK = (Get-PinnedToolchainSDK -OS $Platform.OS);
     SWIFT_PATH_TO_SWIFT_SYNTAX_SOURCE = "$SourceCache\swift-syntax";
     SWIFT_STDLIB_ASSERTIONS = "NO";
     SWIFTSYNTAX_ENABLE_ASSERTIONS = "NO";
@@ -1781,18 +2211,19 @@ function Get-CompilersDefines([Hashtable] $Platform, [switch] $Test) {
   }
 }
 
-function Build-Compilers([Hashtable] $Platform) {
+function Build-Compilers([Hashtable] $Platform, [string] $Variant) {
   New-Item -ItemType SymbolicLink -Path "$BinaryCache\$($HostPlatform.Triple)\compilers" -Target "$BinaryCache\5" -ErrorAction Ignore
   Build-CMakeProject `
     -Src $SourceCache\llvm-project\llvm `
     -Bin (Get-ProjectBinaryCache $Platform Compilers) `
-    -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
+    -InstallTo "$(Get-InstallDir $Platform)\Toolchains\$ProductVersion+$Variant\usr" `
     -Platform $Platform `
-    -UseMSVCCompilers C,CXX `
-    -UsePinnedCompilers Swift `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("C", "CXX") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("Swift") } else { @("C", "CXX", "Swift") }) `
+    -SwiftSDK (Get-PinnedToolchainSDK -OS $Platform.OS) `
     -BuildTargets @("install-distribution") `
     -CacheScript $SourceCache\swift\cmake\caches\Windows-$($Platform.Architecture.LLVMName).cmake `
-    -Defines (Get-CompilersDefines $Platform)
+    -Defines (Get-CompilersDefines $Platform $Variant)
 
   $Settings = @{
     FallbackLibrarySearchPaths = @("usr/bin")
@@ -1802,10 +2233,10 @@ function Build-Compilers([Hashtable] $Platform) {
   Write-PList -Settings $Settings -Path "$($Platform.ToolchainInstallRoot)\ToolchainInfo.plist"
 }
 
-function Test-Compilers([Hashtable] $Platform, [switch] $TestClang, [switch] $TestLLD, [switch] $TestLLDB, [switch] $TestLLVM, [switch] $TestSwift) {
+function Test-Compilers([Hashtable] $Platform, [string] $Variant, [switch] $TestClang, [switch] $TestLLD, [switch] $TestLLDB, [switch] $TestLLVM, [switch] $TestSwift) {
   Invoke-IsolatingEnvVars {
     $env:Path = "$(Get-CMarkBinaryCache $Platform)\src;$(Get-ProjectBinaryCache $BuildPlatform Compilers)\tools\swift\libdispatch-windows-$($Platform.Architecture.LLVMName)-prefix\bin;$(Get-ProjectBinaryCache $BuildPlatform Compilers)\bin;$env:Path;$VSInstallRoot\DIA SDK\bin\$($HostPlatform.Architecture.VSName);$UnixToolsBinDir"
-    $TestingDefines = Get-CompilersDefines $Platform -Test
+    $TestingDefines = Get-CompilersDefines $Platform $Variant -Test
     if ($TestLLVM) { $Targets += @("check-llvm") }
     if ($TestClang) { $Targets += @("check-clang") }
     if ($TestLLD) { $Targets += @("check-lld") }
@@ -1814,18 +2245,24 @@ function Test-Compilers([Hashtable] $Platform, [switch] $TestClang, [switch] $Te
       $Targets += @("check-lldb")
 
       # Override test filter for known issues in downstream LLDB
-      Load-LitTestOverrides $PSScriptRoot/windows-llvm-lit-test-overrides.txt
+      Load-LitTestOverrides ([IO.Path]::GetFullPath([IO.Path]::Combine($PSScriptRoot, "..", "..", "llvm-project", "lldb", "test", "windows-swift-llvm-lit-test-overrides.txt")))
 
       # Transitive dependency of _lldb.pyd
       $RuntimeBinaryCache = Get-ProjectBinaryCache $BuildPlatform Runtime
-      Copy-Item $RuntimeBinaryCache\bin\swiftCore.dll "$(Get-ProjectBinaryCache $BuildPlatform Compilers)\lib\site-packages\lldb"
+      Copy-Item `
+        -Path $RuntimeBinaryCache\bin\swiftCore.dll `
+        -Destination "$(Get-ProjectBinaryCache $BuildPlatform Compilers)\lib\site-packages\lldb"
 
       # Runtime dependencies of repl_swift.exe
       $SwiftRTSubdir = "lib\swift\windows"
       Write-Host "Copying '$RuntimeBinaryCache\$SwiftRTSubdir\$($Platform.Architecture.LLVMName)\swiftrt.obj' to '$(Get-ProjectBinaryCache $BuildPlatform Compilers)\$SwiftRTSubdir'"
-      Copy-Item "$RuntimeBinaryCache\$SwiftRTSubdir\$($Platform.Architecture.LLVMName)\swiftrt.obj" "$(Get-ProjectBinaryCache $BuildPlatform Compilers)\$SwiftRTSubdir"
+      Copy-Item `
+        -Path "$RuntimeBinaryCache\$SwiftRTSubdir\$($Platform.Architecture.LLVMName)\swiftrt.obj" `
+        -Destination "$(Get-ProjectBinaryCache $BuildPlatform Compilers)\$SwiftRTSubdir"
       Write-Host "Copying '$RuntimeBinaryCache\bin\swiftCore.dll' to '$(Get-ProjectBinaryCache $BuildPlatform Compilers)\bin'"
-      Copy-Item "$RuntimeBinaryCache\bin\swiftCore.dll" "$(Get-ProjectBinaryCache $BuildPlatform Compilers)\bin"
+      Copy-Item `
+        -Path "$RuntimeBinaryCache\bin\swiftCore.dll" `
+        -Destination "$(Get-ProjectBinaryCache $BuildPlatform Compilers)\bin"
 
       $TestingDefines += @{
         LLDB_INCLUDE_TESTS = "YES";
@@ -1834,9 +2271,9 @@ function Test-Compilers([Hashtable] $Platform, [switch] $TestClang, [switch] $Te
         # No watchpoint support on windows: https://github.com/llvm/llvm-project/issues/24820
         LLDB_TEST_USER_ARGS = "--skip-category=watchpoint";
         # gtest sharding breaks llvm-lit's --xfail and LIT_XFAIL inputs: https://github.com/llvm/llvm-project/issues/102264
-        LLVM_LIT_ARGS = "-v --no-gtest-sharding --show-xfail";
+        LLVM_LIT_ARGS = "-v --no-gtest-sharding --time-tests";
         # LLDB Unit tests link against this library
-        LLVM_UNITTEST_LINK_FLAGS = "$(Get-SwiftSDK Windows)\usr\lib\swift\windows\$($Platform.Architecture.LLVMName)\swiftCore.lib";
+        LLVM_UNITTEST_LINK_FLAGS = "$(Get-SwiftSDK -OS Windows -Identifier Windows)\usr\lib\swift\windows\$($Platform.Architecture.LLVMName)\swiftCore.lib";
       }
     }
 
@@ -1849,8 +2286,9 @@ function Test-Compilers([Hashtable] $Platform, [switch] $TestClang, [switch] $Te
       -Bin $(Get-ProjectBinaryCache $Platform Compilers) `
       -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
       -Platform $Platform `
-      -UseMSVCCompilers C,CXX `
-      -UsePinnedCompilers Swift `
+      -UseMSVCCompilers $(if ($UseHostToolchain) { @("C", "CXX") } else { @("") }) `
+      -UsePinnedCompilers $(if ($UseHostToolchain) { @("Swift") } else { @("C", "CXX", "Swift") }) `
+      -SwiftSDK (Get-PinnedToolchainSDK -OS $Platform.OS) `
       -BuildTargets $Targets `
       -CacheScript $SourceCache\swift\cmake\caches\Windows-$($Platform.Architecture.LLVMName).cmake `
       -Defines $TestingDefines
@@ -1897,19 +2335,24 @@ function Build-mimalloc() {
   Invoke-Program $msbuild "$SourceCache\mimalloc\ide\vs2022\mimalloc-override-dll.vcxproj" @MSBuildArgs "-p:IntDir=$BinaryCache\$($Platform.Triple)\mimalloc\mimalloc-override-dll\"
 
   $HostSuffix = if ($Platform -eq $KnownPlatforms["WindowsX64"]) { "" } else { "-arm64" }
-  $BuildSuffix = if ($BuildPlatform -eq $KnownPlatforms["WindowsX64"]) { "" } else { "-arm64" }
 
   foreach ($item in "mimalloc.dll", "mimalloc-redirect$HostSuffix.dll") {
-    Copy-Item -Path "$BinaryCache\$($Platform.Triple)\mimalloc\bin\$item" -Destination "$($Platform.ToolchainInstallRoot)\usr\bin\"
+    Copy-Item `
+      -Path "$BinaryCache\$($Platform.Triple)\mimalloc\bin\$item" `
+      -Destination "$($Platform.ToolchainInstallRoot)\usr\bin\"
   }
+}
 
-  # When cross-compiling, bundle the second mimalloc redirect dll as a workaround for
-  # https://github.com/microsoft/mimalloc/issues/997
-  if ($IsCrossCompiling) {
-    Copy-Item -Path "$BinaryCache\$($Platform.Triple)\mimalloc\bin\mimalloc-redirect$HostSuffix.dll" -Destination "$($Platform.ToolchainInstallRoot)\usr\bin\mimalloc-redirect$BuildSuffix.dll"
-  }
+function Patch-mimalloc() {
+  [CmdletBinding(PositionalBinding = $false)]
+  param
+  (
+    [Parameter(Position = 0, Mandatory = $true)]
+    [hashtable]$Platform
+  )
+
+  $BuildSuffix = if ($BuildPlatform -eq $KnownPlatforms["WindowsX64"]) { "" } else { "-arm64" }
 
-  # TODO: should we split this out into its own function?
   $Tools = @(
     "swift.exe",
     "swiftc.exe",
@@ -1923,19 +2366,24 @@ function Build-mimalloc() {
     "ld.lld.exe",
     "ld64.lld.exe"
   )
-  foreach ($Tool in $Tools) {
-    $Binary = [IO.Path]::Combine($Platform.ToolchainInstallRoot, "usr", "bin", $Tool)
+  $Binaries = $Tools | ForEach-Object {[IO.Path]::Combine($Platform.ToolchainInstallRoot, "usr", "bin", $_)}
+  if ($IncludeNoAsserts) {
+    $NoAssertBinaries = $Tools | ForEach-Object {[IO.Path]::Combine($Platform.NoAssertsToolchainInstallRoot, "usr", "bin", $_)}
+    $Binaries = $Binaries + $NoAssertBinaries
+  }
+  foreach ($Binary in $Binaries) {
+    $Name = [IO.Path]::GetFileName($Binary)
     # Binary-patch in place
     Invoke-Program "$SourceCache\mimalloc\bin\minject$BuildSuffix" "-f" "-i" "$Binary"
     # Log the import table
-    $LogFile = "$BinaryCache\$($Platform.Triple)\mimalloc\minject-log-$Tool.txt"
-    $ErrorFile = "$BinaryCache\$($Platform.Triple)\mimalloc\minject-log-$Tool-error.txt"
+    $LogFile = "$BinaryCache\$($Platform.Triple)\mimalloc\minject-log-$Name.txt"
+    $ErrorFile = "$BinaryCache\$($Platform.Triple)\mimalloc\minject-log-$Name-error.txt"
     Invoke-Program "$SourceCache\mimalloc\bin\minject$BuildSuffix" "-l" "$Binary" -OutFile $LogFile -ErrorFile $ErrorFile
     # Verify patching
     $Found = Select-String -Path $LogFile -Pattern "mimalloc"
     if (-not $Found) {
       Get-Content $ErrorFile
-      throw "Failed to patch mimalloc for $Tool"
+      throw "Failed to patch mimalloc for $Name"
     }
   }
 }
@@ -1947,45 +2395,43 @@ function Build-LLVM([Hashtable] $Platform) {
     -Platform $Platform `
     -UseBuiltCompilers C,CXX `
     -Defines @{
-      CMAKE_SYSTEM_NAME = $Platform.OS.ToString();
       LLVM_HOST_TRIPLE = $Platform.Triple;
     }
 }
 
-function Build-Sanitizers([Hashtable] $Platform) {
-  $LLVMTargetCache = $(Get-ProjectBinaryCache $Platform LLVM)
-  $LITVersionStr = $(Invoke-Program $(Get-PythonExecutable) "$LLVMTargetCache\bin\llvm-lit.py" --version)
-  if (-not ($LITVersionStr -match "lit (\d+)\.\d+\.\d+.*")) {
-    throw "Unexpected version string output from llvm-lit.py"
+function Build-CompilerRuntime([Hashtable] $Platform) {
+  $LLVMBinaryCache = $(Get-ProjectBinaryCache $HostPlatform Compilers)
+
+  $LITVersionStr = $(Invoke-Program $(Get-PythonExecutable) "$LLVMBinaryCache\bin\llvm-lit.py" --version)
+  if (-not $ToBatch -and -not ($LITVersionStr -match "lit (\d+)\.\d+\.\d+.*")) {
+    throw "Unexpected version string '$LITVersionStr' output from llvm-lit.py"
   }
   $LLVMVersionMajor = $Matches.1
-  $InstallTo = "$($HostPlatform.ToolchainInstallRoot)\usr\lib\clang\$LLVMVersionMajor"
-  Write-Host "Sanitizers SDK directory: $InstallTo"
+
+  $InstallRoot = "$($HostPlatform.ToolchainInstallRoot)\usr\lib\clang\$LLVMVersionMajor"
 
   Build-CMakeProject `
     -Src $SourceCache\llvm-project\compiler-rt\lib\builtins `
     -Bin "$(Get-ProjectBinaryCache $Platform ClangBuiltins)" `
-    -InstallTo $InstallTo `
+    -InstallTo $InstallRoot `
     -Platform $Platform `
     -UseBuiltCompilers ASM,C,CXX `
     -BuildTargets "install-compiler-rt" `
-    -Defines (@{
-      CMAKE_SYSTEM_NAME = $Platform.OS.ToString();
-      LLVM_DIR = "$LLVMTargetCache\lib\cmake\llvm";
+    -Defines @{
+      LLVM_DIR = "$LLVMBinaryCache\lib\cmake\llvm";
       LLVM_ENABLE_PER_TARGET_RUNTIME_DIR = "YES";
       COMPILER_RT_DEFAULT_TARGET_ONLY = "YES";
-    })
+    }
 
   Build-CMakeProject `
     -Src $SourceCache\llvm-project\compiler-rt `
     -Bin "$(Get-ProjectBinaryCache $Platform ClangRuntime)" `
-    -InstallTo $InstallTo `
+    -InstallTo $InstallRoot `
     -Platform $Platform `
     -UseBuiltCompilers ASM,C,CXX `
     -BuildTargets "install-compiler-rt" `
-    -Defines (@{
-      CMAKE_SYSTEM_NAME = $Platform.OS.ToString();
-      LLVM_DIR = "$LLVMTargetCache\lib\cmake\llvm";
+    -Defines @{
+      LLVM_DIR = "$LLVMBinaryCache\lib\cmake\llvm";
       LLVM_ENABLE_PER_TARGET_RUNTIME_DIR = "YES";
       COMPILER_RT_DEFAULT_TARGET_ONLY = "YES";
       COMPILER_RT_BUILD_BUILTINS = "NO";
@@ -1995,42 +2441,34 @@ function Build-Sanitizers([Hashtable] $Platform) {
       COMPILER_RT_BUILD_XRAY = "NO";
       COMPILER_RT_BUILD_PROFILE = "YES";
       COMPILER_RT_BUILD_SANITIZERS = "YES";
-    })
+    }
 }
 
 function Build-ZLib([Hashtable] $Platform) {
-  $ArchName = $Platform.Architecture.LLVMName
-
   Build-CMakeProject `
     -Src $SourceCache\zlib `
-    -Bin "$BinaryCache\$($Platform.Triple)\zlib-1.3.1" `
-    -InstallTo $LibraryRoot\zlib-1.3.1\usr `
+    -Bin "$BinaryCache\$($Platform.Triple)\zlib" `
+    -InstallTo "$BinaryCache\$($Platform.Triple)\usr" `
     -Platform $Platform `
-    -UseMSVCCompilers C `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("C") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("C") }) `
     -Defines @{
       BUILD_SHARED_LIBS = "NO";
       CMAKE_POSITION_INDEPENDENT_CODE = "YES";
-      CMAKE_SYSTEM_NAME = $Platform.OS.ToString();
-      INSTALL_BIN_DIR = "$LibraryRoot\zlib-1.3.1\usr\bin\$($Platform.OS.ToString())\$ArchName";
-      INSTALL_LIB_DIR = "$LibraryRoot\zlib-1.3.1\usr\lib\$($Platform.OS.ToString())\$ArchName";
     }
 }
 
 function Build-XML2([Hashtable] $Platform) {
-  $ArchName = $Platform.Architecture.LLVMName
-
   Build-CMakeProject `
     -Src $SourceCache\libxml2 `
     -Bin "$BinaryCache\$($Platform.Triple)\libxml2-2.11.5" `
-    -InstallTo "$LibraryRoot\libxml2-2.11.5\usr" `
+    -InstallTo "$BinaryCache\$($Platform.Triple)\usr" `
     -Platform $Platform `
-    -UseMSVCCompilers C,CXX `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("C", "CXX") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("C", "CXX") }) `
     -Defines @{
       BUILD_SHARED_LIBS = "NO";
-      CMAKE_INSTALL_BINDIR = "bin/$($Platform.OS.ToString())/$ArchName";
-      CMAKE_INSTALL_LIBDIR = "lib/$($Platform.OS.ToString())/$ArchName";
       CMAKE_POSITION_INDEPENDENT_CODE = "YES";
-      CMAKE_SYSTEM_NAME = $Platform.OS.ToString();
       LIBXML2_WITH_ICONV = "NO";
       LIBXML2_WITH_ICU = "NO";
       LIBXML2_WITH_LZMA = "NO";
@@ -2047,7 +2485,8 @@ function Build-RegsGen2([Hashtable] $Platform) {
     -Bin (Get-ProjectBinaryCache $Platform RegsGen2) `
     -Platform $Platform `
     -BuildTargets default `
-    -UseMSVCCompilers C,CXX `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("C", "CXX") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("C", "CXX") }) `
     -Defines @{
       BISON_EXECUTABLE = "$(Get-BisonExecutable)";
       FLEX_EXECUTABLE = "$(Get-FlexExecutable)";
@@ -2061,7 +2500,6 @@ function Build-DS2([Hashtable] $Platform) {
     -InstallTo "$(Get-PlatformRoot $Platform.OS)\Developer\Library\ds2\usr" `
     -Platform $Platform `
     -Defines @{
-      CMAKE_SYSTEM_NAME = $Platform.OS.ToString();
       DS2_REGSGEN2 = "$(Get-ProjectBinaryCache $BuildPlatform RegsGen2)/regsgen2.exe";
       DS2_PROGRAM_PREFIX = "$(Get-ModuleTriple $Platform)-";
       BISON_EXECUTABLE = "$(Get-BisonExecutable)";
@@ -2070,8 +2508,6 @@ function Build-DS2([Hashtable] $Platform) {
 }
 
 function Build-CURL([Hashtable] $Platform) {
-  $ArchName = $Platform.Architecture.LLVMName
-
   $PlatformDefines = @{}
   if ($Platform.OS -eq [OS]::Android) {
     $PlatformDefines += @{
@@ -2081,16 +2517,15 @@ function Build-CURL([Hashtable] $Platform) {
 
   Build-CMakeProject `
     -Src $SourceCache\curl `
-    -Bin "$BinaryCache\$($Platform.Triple)\curl-8.9.1" `
-    -InstallTo "$LibraryRoot\curl-8.9.1\usr" `
+    -Bin "$BinaryCache\$($Platform.Triple)\curl" `
+    -InstallTo "$BinaryCache\$($Platform.Triple)\usr" `
     -Platform $Platform `
-    -UseMSVCCompilers C `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("C") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("C") }) `
     -Defines ($PlatformDefines + @{
       BUILD_SHARED_LIBS = "NO";
       BUILD_TESTING = "NO";
-      CMAKE_INSTALL_LIBDIR = "lib/$($Platform.OS.ToString())/$ArchName";
       CMAKE_POSITION_INDEPENDENT_CODE = "YES";
-      CMAKE_SYSTEM_NAME = $Platform.OS.ToString();
       BUILD_CURL_EXE = "NO";
       BUILD_LIBCURL_DOCS = "NO";
       BUILD_MISC_DOCS = "NO";
@@ -2173,8 +2608,8 @@ function Build-CURL([Hashtable] $Platform) {
       USE_WIN32_IDN = if ($Platform.OS -eq [OS]::Windows) { "YES" } else { "NO" };
       USE_WIN32_LARGE_FILES = if ($Platform.OS -eq [OS]::Windows) { "YES" } else { "NO" };
       USE_WIN32_LDAP = "NO";
-      ZLIB_ROOT = "$LibraryRoot\zlib-1.3.1\usr";
-      ZLIB_LIBRARY = "$LibraryRoot\zlib-1.3.1\usr\lib\$($Platform.OS.ToString())\$ArchName\zlibstatic.lib";
+      ZLIB_ROOT = "$BinaryCache\$($Platform.Triple)\usr";
+      ZLIB_LIBRARY = "$BinaryCache\$($Platform.Triple)\usr\lib\zlibstatic.lib";
     })
 }
 
@@ -2184,22 +2619,24 @@ function Build-Runtime([Hashtable] $Platform) {
     $PlatformDefines += @{
       LLVM_ENABLE_LIBCXX = "YES";
       SWIFT_USE_LINKER = "lld";
-      # Clang[<18] doesn't provide the _Builtin_float module.
-      SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT = "YES";
+    }
+
+    if ((Get-AndroidNDK).ClangVersion -lt 18) {
+      $PlatformDefines += @{
+        SWIFT_BUILD_CLANG_OVERLAYS_SKIP_BUILTIN_FLOAT = "YES";
+      }
     }
   }
 
   Build-CMakeProject `
     -Src $SourceCache\swift `
     -Bin (Get-ProjectBinaryCache $Platform Runtime) `
-    -InstallTo "$(Get-SwiftSDK $Platform.OS)\usr" `
+    -InstallTo "$(Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK)\usr" `
     -Platform $Platform `
-    -CacheScript $SourceCache\swift\cmake\caches\Runtime-$($Platform.OS.ToString())-$($Platform.Architecture.LLVMName).cmake `
     -UseBuiltCompilers C,CXX,Swift `
+    -SwiftSDK $null `
+    -CacheScript $SourceCache\swift\cmake\caches\Runtime-$($Platform.OS.ToString())-$($Platform.Architecture.LLVMName).cmake `
     -Defines ($PlatformDefines + @{
-      CMAKE_Swift_COMPILER_TARGET = (Get-ModuleTriple $Platform);
-      CMAKE_Swift_COMPILER_WORKS = "YES";
-      CMAKE_SYSTEM_NAME = $Platform.OS.ToString();
       LLVM_DIR = "$(Get-ProjectBinaryCache $Platform LLVM)\lib\cmake\llvm";
       SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY = "YES";
       SWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP = "YES";
@@ -2212,7 +2649,6 @@ function Build-Runtime([Hashtable] $Platform) {
       SWIFT_NATIVE_SWIFT_TOOLS_PATH = ([IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform Compilers), "bin"));
       SWIFT_PATH_TO_LIBDISPATCH_SOURCE = "$SourceCache\swift-corelibs-libdispatch";
       SWIFT_PATH_TO_STRING_PROCESSING_SOURCE = "$SourceCache\swift-experimental-string-processing";
-      CMAKE_SHARED_LINKER_FLAGS = if ($Platform.OS -eq [OS]::Windows) { @("/INCREMENTAL:NO", "/OPT:REF", "/OPT:ICF") } else { @() };
     })
 }
 
@@ -2229,104 +2665,306 @@ function Test-Runtime([Hashtable] $Platform) {
     throw "LIT test utilities not found in $CompilersBinaryCache\bin"
   }
 
-  Invoke-IsolatingEnvVars {
-    # Filter known issues when testing on Windows
-    Load-LitTestOverrides $PSScriptRoot/windows-swift-android-lit-test-overrides.txt
-    $env:Path = "$(Get-CMarkBinaryCache $Platform)\src;$(Get-PinnedToolchainRuntime);${env:Path};$UnixToolsBinDir"
+  Invoke-IsolatingEnvVars {
+    # Filter known issues when testing on Windows
+    Load-LitTestOverrides $PSScriptRoot/windows-swift-android-lit-test-overrides.txt
+    $env:Path = "$(Get-CMarkBinaryCache $Platform)\src;$(Get-PinnedToolchainRuntime);${env:Path};$UnixToolsBinDir"
+    Build-CMakeProject `
+      -Src $SourceCache\swift `
+      -Bin (Get-ProjectBinaryCache $Platform Runtime) `
+      -Platform $Platform `
+      -UseBuiltCompilers C,CXX,Swift `
+      -SwiftSDK $null `
+      -BuildTargets check-swift-validation-only_non_executable `
+      -Defines @{
+        SWIFT_INCLUDE_TESTS = "YES";
+        SWIFT_INCLUDE_TEST_BINARIES = "YES";
+        SWIFT_BUILD_TEST_SUPPORT_MODULES = "YES";
+        SWIFT_NATIVE_LLVM_TOOLS_PATH = Join-Path -Path $CompilersBinaryCache -ChildPath "bin";
+        LLVM_LIT_ARGS = "-vv";
+      }
+  }
+}
+
+function Build-ExperimentalRuntime([Hashtable] $Platform, [switch] $Static = $false) {
+  # TODO: remove this once the migration is completed.
+  Invoke-IsolatingEnvVars {
+    Invoke-VsDevShell $BuildPlatform
+
+    Push-Location "${SourceCache}\swift\Runtimes"
+    Start-Process -Wait -WindowStyle Hidden -FilePath $cmake -ArgumentList @("-P", "Resync.cmake")
+    Pop-Location
+  }
+
+  Invoke-IsolatingEnvVars {
+    $env:Path = "$(Get-CMarkBinaryCache $Platform)\src;$(Get-PinnedToolchainRuntime);${env:Path}"
+
+    $SDKRoot = Get-SwiftSDK -OS $Platform.OS -Identifier "$($Platform.OS)Experimental"
+
+    $RuntimeBinaryCache = if ($Static) {
+      Get-ProjectBinaryCache $Platform ExperimentalStaticRuntime
+    } else {
+      Get-ProjectBinaryCache $Platform ExperimentalDynamicRuntime
+    }
+
+    $OverlayBinaryCache = if ($Static) {
+      Get-ProjectBinaryCache $Platform ExperimentalStaticOverlay
+    } else {
+      Get-ProjectBinarycache $Platform ExperimentalDynamicOverlay
+    }
+
+    $StringProcessingBinaryCache = if ($Static) {
+      Get-ProjectBinarycache $Platform ExperimentalStaticStringProcessing
+    } else {
+      Get-ProjectBinarycache $Platform ExperimentalDynamicStringProcessing
+    }
+
+    $SynchronizationBinaryCache = if ($Static) {
+      Get-ProjectBinarycache $Platform ExperimentalStaticSynchronization
+    } else {
+      Get-ProjectBinarycache $Platform ExperimentalDynamicSynchronization
+    }
+
+    $DistributedBinaryCache = if ($Static) {
+      Get-ProjectBinarycache $Platform ExperimentalStaticDistributed
+    } else {
+      Get-ProjectBinarycache $Platform ExperimentalDynamicDistributed
+    }
+
+    $ObservationBinaryCache = if ($Static) {
+      Get-ProjectBinarycache $Platform ExperimentalStaticObservation
+    } else {
+      Get-ProjectBinaryCache $Platform ExperimentalDynamicObservation
+    }
+
+    $DifferentiationBinaryCache = if ($Static) {
+      Get-ProjectBinarycache $Platform ExperimentalStaticDifferentiation
+    } else {
+      Get-ProjectBinarycache $Platform ExperimentalDynamicDifferentiation
+    }
+
+    $VolatileBinaryCache = if ($Static) {
+      Get-ProjectBinarycache $Platform ExperimentalStaticVolatile
+    } else {
+      Get-ProjectBinaryCache $Platform ExperimentalDynamicVolatile
+    }
+
+    Build-CMakeProject `
+      -Src $SourceCache\swift\Runtimes\Core `
+      -Bin $RuntimeBinaryCache `
+      -InstallTo "${SDKRoot}\usr" `
+      -Platform $Platform `
+      -UseBuiltCompilers C,CXX,Swift `
+      -SwiftSDK $null `
+      -UseGNUDriver `
+      -Defines @{
+        BUILD_SHARED_LIBS = if ($Static) { "NO" } else { "YES" };
+        CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+
+        dispatch_DIR = (Get-ProjectCMakeModules $Platform CDispatch);
+
+        # FIXME(compnerd) remove this once the default option is flipped to `ON`.
+        SwiftCore_ENABLE_CONCURRENCY = "YES";
+        # FIXME(compnerd) remove this once the default option is flipped to `ON`.
+        SwiftCore_ENABLE_REMOTE_MIRROR = "YES";
+        # FIXME(compnerd) this currently causes a build failure on Windows, but
+        # this should be enabled when building the dynamic runtime.
+        SwiftCore_ENABLE_LIBRARY_EVOLUTION = "NO";
+      }
+
+    Build-CMakeProject `
+      -Src $SourceCache\swift\Runtimes\Overlay `
+      -Bin $OverlayBinaryCache `
+      -InstallTo "${SDKRoot}\usr" `
+      -Platform $Platform `
+      -UseBuiltCompilers C,CXX,Swift `
+      -SwiftSDK $null `
+      -UseGNUDriver `
+      -Defines @{
+        BUILD_SHARED_LIBS = if ($Static) { "NO" } else { "YES" };
+        CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+
+        SwiftCore_DIR = "${RuntimeBinaryCache}\cmake\SwiftCore";
+
+        # FIXME(compnerd) this currently causes a build failure on Windows, but
+        # this should be enabled when building the dynamic runtime.
+        SwiftOverlay_ENABLE_LIBRARY_EVOLUTION = "NO";
+        SwiftOverlay_ENABLE_CXX_INTEROP = "YES";
+      }
+
+    Build-CMakeProject `
+      -Src $SourceCache\swift\Runtimes\Supplemental\StringProcessing `
+      -Bin $StringProcessingBinaryCache `
+      -InstallTo "${SDKRoot}\usr" `
+      -Platform $Platform `
+      -UseBuiltCompilers C,Swift `
+      -SwiftSDK $null `
+      -UseGNUDriver `
+      -Defines @{
+        BUILD_SHARED_LIBS = if ($Static) { "NO" } else { "YES" };
+        CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+
+        SwiftCore_DIR = "${RuntimeBinaryCache}\cmake\SwiftCore";
+        # FIXME(compnerd) this currently causes a build failure on Windows, but
+        # this should be enabled when building the dynamic runtime.
+        SwiftStringProcessing_ENABLE_LIBRARY_EVOLUTION = "NO";
+      }
+
+    Build-CMakeProject `
+      -Src $SourceCache\swift\Runtimes\Supplemental\Synchronization `
+      -Bin $SynchronizationBinaryCache `
+      -InstallTo "${SDKRoot}\usr" `
+      -Platform $Platform `
+      -UseBuiltCompilers C,Swift `
+      -SwiftSDK $null `
+      -UseGNUDriver `
+      -Defines @{
+        BUILD_SHARED_LIBS = if ($Static) { "NO" } else { "YES" };
+        CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+
+        SwiftCore_DIR = "${RuntimeBinaryCache}\cmake\SwiftCore";
+        SwiftOverlay_DIR = "${OverlayBinaryCache}\cmake\SwiftOverlay";
+        # FIXME(compnerd) this currently causes a build failure on Windows, but
+        # this should be enabled when building the dynamic runtime.
+        SwiftSynchronization_ENABLE_LIBRARY_EVOLUTION = "NO";
+      }
+
     Build-CMakeProject `
-      -Src $SourceCache\swift `
-      -Bin (Get-ProjectBinaryCache $Platform Runtime) `
+      -Src $SourceCache\swift\Runtimes\Supplemental\Distributed `
+      -Bin $DistributedBinaryCache `
+      -InstallTo "${SDKRoot}\usr" `
       -Platform $Platform `
       -UseBuiltCompilers C,CXX,Swift `
-      -BuildTargets check-swift-validation-only_non_executable `
+      -SwiftSDK $null `
+      -UseGNUDriver `
       -Defines @{
-        SWIFT_INCLUDE_TESTS = "YES";
-        SWIFT_INCLUDE_TEST_BINARIES = "YES";
-        SWIFT_BUILD_TEST_SUPPORT_MODULES = "YES";
-        SWIFT_NATIVE_LLVM_TOOLS_PATH = Join-Path -Path $CompilersBinaryCache -ChildPath "bin";
-        LLVM_LIT_ARGS = "-vv";
+        BUILD_SHARED_LIBS = if ($Static) { "NO" } else { "YES" };
+        # FIXME(#83449): avoid using `SwiftCMakeConfig.h`
+        CMAKE_CXX_FLAGS = @("-I${RuntimeBinaryCache}\include");
+        CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+
+        SwiftCore_DIR = "${RuntimeBinaryCache}\cmake\SwiftCore";
+        SwiftOverlay_DIR = "${OverlayBinaryCache}\cmake\SwiftOverlay";
+        # FIXME(compnerd) this currently causes a build failure on Windows, but
+        # this should be enabled when building the dynamic runtime.
+        SwiftDistributed_ENABLE_LIBRARY_EVOLUTION = "NO";
       }
-  }
-}
 
-function Build-ExperimentalRuntime {
-  [CmdletBinding(PositionalBinding = $false)]
-  param
-  (
-    [Parameter(Position = 0, Mandatory = $true)]
-    [Hashtable] $Platform,
-    [switch] $Static = $false
-  )
+    Build-CMakeProject `
+      -Src $SourceCache\swift\Runtimes\Supplemental\Observation `
+      -Bin $ObservationBinaryCache `
+      -InstallTo "${SDKRoot}\usr" `
+      -Platform $Platform `
+      -UseBuiltCompilers CXX,Swift `
+      -SwiftSDK $null `
+      -UseGNUDriver `
+      -Defines @{
+        BUILD_SHARED_LIBS = if ($Static) { "NO" } else { "YES" };
+        # FIXME(#83449): avoid using `SwiftCMakeConfig.h`
+        CMAKE_CXX_FLAGS = @("-I${RuntimeBinaryCache}\include");
+        CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
 
-  # TODO: remove this once the migration is completed.
-  Invoke-IsolatingEnvVars {
-    Invoke-VsDevShell $BuildPlatform
+        SwiftCore_DIR = "${RuntimeBinaryCache}\cmake\SwiftCore";
+        SwiftOverlay_DIR = "${OverlayBinaryCache}\cmake\SwiftOverlay";
+        # FIXME(compnerd) this currently causes a build failure on Windows, but
+        # this should be enabled when building the dynamic runtime.
+        SwiftObservation_ENABLE_LIBRARY_EVOLUTION = "NO";
+      }
 
-    Push-Location "${SourceCache}\swift\Runtimes"
-    Start-Process -Wait -WindowStyle Hidden -FilePath cmake.exe -ArgumentList @("-P", "Resync.cmake")
-    Pop-Location
-  }
+    Build-CMakeProject `
+      -Src $SourceCache\swift\Runtimes\Supplemental\Differentiation `
+      -Bin $DifferentiationBinaryCache `
+      -InstallTo "${SDKRoot}\usr" `
+      -Platform $Platform `
+      -UseBuiltCompilers C,CXX,Swift `
+      -SwiftSDK $null `
+      -UseGNUDriver `
+      -Defines @{
+        BUILD_SHARED_LIBS = if ($Static) { "NO" } else { "YES" };
+        CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
 
-  Invoke-IsolatingEnvVars {
-    $env:Path = "$(Get-CMarkBinaryCache $Platform)\src;$(Get-PinnedToolchainRuntime);${env:Path}"
+        SwiftCore_DIR = "${RuntimeBinaryCache}\cmake\SwiftCore";
+        SwiftOverlay_DIR = "${OverlayBinaryCache}\cmake\SwiftOverlay";
+        # FIXME(compnerd) this currently causes a build failure on Windows, but
+        # this should be enabled when building the dynamic runtime.
+        SwiftDifferentiation_ENABLE_LIBRARY_EVOLUTION = "NO";
+      }
 
     Build-CMakeProject `
-      -Src $SourceCache\swift\Runtimes\Core `
-      -Bin (Get-ProjectBinaryCache $Platform ExperimentalRuntime) `
-      -InstallTo "$(Get-SwiftSDK $Platform.OS -Identifier "$($Platform.OS)Experimental")\usr" `
+      -Src $SourceCache\swift\Runtimes\Supplemental\Volatile `
+      -Bin $VolatileBinaryCache `
+      -InstallTo "${SDKROOT}\usr" `
       -Platform $Platform `
-      -UseBuiltCompilers C,CXX,Swift `
+      -UseBuiltCompilers C,Swift `
+      -SwiftSDK $null `
       -UseGNUDriver `
       -Defines @{
         BUILD_SHARED_LIBS = if ($Static) { "NO" } else { "YES" };
         CMAKE_FIND_PACKAGE_PREFER_CONFIG = "YES";
         CMAKE_Swift_COMPILER_TARGET = (Get-ModuleTriple $Platform);
-        CMAKE_Swift_COMPILER_WORKS = "YES";
         CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
-        CMAKE_SYSTEM_NAME = $Platform.OS.ToString();
-        dispatch_DIR = (Get-ProjectCMakeModules $Platform Dispatch);
-        SwiftCore_ENABLE_CONCURRENCY = "YES";
+
+        SwiftCore_DIR = "${RuntimeBinaryCache}\cmake\SwiftCore";
+        SwiftOverlay_DIR = "${OverlayBinaryCache}\cmake\SwiftOverlay";
+        # FIXME(compnerd) this currently causes a build failure on Windows, but
+        # this should be enabled when building the dynamic runtime.
+        SwiftVolatile_ENABLE_LIBRARY_EVOLUTION = "NO";
       }
   }
 }
 
-function Write-SDKSettingsPlist([Hashtable] $Platform) {
-  $SDKSettings = @{
-    DefaultProperties = @{
-    }
-  }
-  if ($Platform.OS -eq [OS]::Windows) {
-    $SDKSettings.DefaultProperties.DEFAULT_USE_RUNTIME = "MD"
-  }
-  Write-PList -Settings $SDKSettings -Path "$(Get-SwiftSDK $Platform.OS)\SDKSettings.plist"
-
+function Write-SDKSettings([OS] $OS, [string] $Identifier = $OS.ToString()) {
   $SDKSettings = @{
-    CanonicalName = "$($Platform.Triple)"
-    DisplayName = "$($Platform.OS.ToString())"
-    IsBaseSDK = "NO"
+    CanonicalName = $OS.ToString().ToLowerInvariant()
+    DisplayName = $OS.ToString()
+    IsBaseSDK = "YES"
     Version = "${ProductVersion}"
     VersionMap = @{}
+    HeaderSearchPaths = @( "usr/include" );
+    LibrarySearchPaths = @();
+    Toolchains = @( "${ToolchainIdentifier}" );
     DefaultProperties = @{
-      PLATFORM_NAME = "$($Platform.OS.ToString())"
+      PLATFORM_NAME = $OS.ToString().ToLowerInvariant()
       DEFAULT_COMPILER = "${ToolchainIdentifier}"
     }
+    SupportedTargets = @{
+      $OS.ToString().ToLowerInvariant() = @{
+        PlatformFamilyDisplayName = $OS.ToString()
+        PlatformFamilyName = $OS.ToString()
+      }
+    }
   }
-  if ($Platform.OS -eq [OS]::Windows) {
-    $SDKSettings.DefaultProperties.DEFAULT_USE_RUNTIME = "MD"
+  switch ($OS) {
+    Windows {
+      $SDKSettings.DefaultProperties.DEFAULT_USE_RUNTIME = "MD"
+      $SDKSettings.SupportedTargets.windows.LLVMTargetVendor = "unknown"
+      $SDKSettings.SupportedTargets.windows.LLVMTargetSys = "windows"
+      $SDKSettings.SupportedTargets.windows.LLVMTargetTripleEnvironment = "msvc"
+      $SDKSettings.SupportedTargets.windows.Archs = $WindowsSDKBuilds | ForEach-Object { $_.Architecture.LLVMName } | Sort-Object
+    }
+    Android {
+      $SDKSettings.SupportedTargets.android.LLVMTargetVendor = "unknown"
+      $SDKSettings.SupportedTargets.android.LLVMTargetSys = "linux"
+      $SDKSettings.SupportedTargets.android.LLVMTargetTripleEnvironment = "android${AndroidAPILevel}"
+      $SDKSettings.SupportedTargets.android.Archs = $AndroidSDKBuilds | ForEach-Object { $_.Architecture.LLVMName } | Sort-Object
+    }
   }
-  $SDKSettings | ConvertTo-JSON | Out-FIle -FilePath "$(Get-SwiftSDK $Platform.OS)\SDKSettings.json"
+  $SDKSettings | ConvertTo-JSON -Depth 4 | Out-FIle -FilePath "$(Get-SwiftSDK -OS $OS -Identifier $Identifier)\SDKSettings.json"
+  Write-PList -Settings $SDKSettings -Path "$(Get-SwiftSDK -OS $OS -Identifier $Identifier)\SDKSettings.plist"
 }
 
 function Build-Dispatch([Hashtable] $Platform) {
+  $SwiftSDK = Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK
   Build-CMakeProject `
     -Src $SourceCache\swift-corelibs-libdispatch `
     -Bin (Get-ProjectBinaryCache $Platform Dispatch) `
-    -InstallTo "$(Get-SwiftSDK $Platform.OS)\usr" `
+    -InstallTo "${SwiftSDK}\usr" `
     -Platform $Platform `
-    -SwiftSDK (Get-SwiftSDK $Platform.OS) `
     -UseBuiltCompilers C,CXX,Swift `
+    -SwiftSDK $SwiftSDK `
     -Defines @{
       ENABLE_SWIFT = "YES";
+      dispatch_INSTALL_ARCH_SUBDIR = "YES";
     }
 }
 
@@ -2338,82 +2976,72 @@ function Test-Dispatch {
       -Src $SourceCache\swift-corelibs-libdispatch `
       -Bin (Get-ProjectBinaryCache $BuildPlatform Dispatch) `
       -Platform $BuildPlatform `
-      -SwiftSDK (Get-SwiftSDK Windows) `
-      -BuildTargets default,ExperimentalTest `
       -UseBuiltCompilers C,CXX,Swift `
+      -SwiftSDK (Get-SwiftSDK -OS $BuildPlatform.OS -Identifier $BuildPlatform.DefaultSDK) `
+      -BuildTargets default,ExperimentalTest `
       -Defines @{
         ENABLE_SWIFT = "YES";
       }
   }
 }
 
-function Build-Foundation {
-  [CmdletBinding(PositionalBinding = $false)]
-  param
-  (
-    [Parameter(Position = 0, Mandatory = $true)]
-    [Hashtable] $Platform,
-    [switch] $Static = $false
-  )
-
-  $FoundationBinaryCache = if ($Static) {
-    Get-ProjectBinaryCache $Platform StaticFoundation
-  } else {
-    Get-ProjectBinaryCache $Platform DynamicFoundation
-  }
-
+function Build-Foundation([Hashtable] $Platform) {
+  $SwiftSDK = Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK
   Build-CMakeProject `
     -Src $SourceCache\swift-corelibs-foundation `
-    -Bin $FoundationBinaryCache `
-    -InstallTo $(if ($Static) { "$(Get-SwiftSDK $Platform.OS -Identifier "$($Platform.OS)Experimental")\usr" } else { "$(Get-SwiftSDK $Platform.OS)\usr" }) `
+    -Bin (Get-ProjectBinaryCache $Platform DynamicFoundation) `
+    -InstallTo "${SwiftSDK}\usr" `
     -Platform $Platform `
-    -UseBuiltCompilers ASM,C,CXX,Swift `
-    -SwiftSDK (Get-SwiftSDK $Platform.OS) `
+    -UseBuiltCompilers C,CXX,Swift `
+    -SwiftSDK $SwiftSDK `
     -Defines @{
-      BUILD_SHARED_LIBS = if ($Static) { "NO" } else { "YES" };
-      CMAKE_FIND_PACKAGE_PREFER_CONFIG = "YES";
+      BUILD_SHARED_LIBS = "YES";
+      # FIXME(compnerd) - workaround ARM64 build failure when cross-compiling.
       CMAKE_NINJA_FORCE_RESPONSE_FILE = "YES";
       CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
-      ENABLE_TESTING = "NO";
       FOUNDATION_BUILD_TOOLS = if ($Platform.OS -eq [OS]::Windows) { "YES" } else { "NO" };
-      CURL_DIR = "$LibraryRoot\curl-8.9.1\usr\lib\$($Platform.OS.ToString())\$($Platform.Architecture.LLVMName)\cmake\CURL";
-      LibXml2_DIR = "$LibraryRoot\libxml2-2.11.5\usr\lib\$($Platform.OS.ToString())\$($Platform.Architecture.LLVMName)\cmake\libxml2-2.11.5";
+      CURL_DIR = "$BinaryCache\$($Platform.Triple)\usr\lib\cmake\CURL";
+      LibXml2_DIR = "$BinaryCache\$($Platform.Triple)\usr\lib\cmake\libxml2-2.11.5";
       ZLIB_LIBRARY = if ($Platform.OS -eq [OS]::Windows) {
-        "$LibraryRoot\zlib-1.3.1\usr\lib\$($Platform.OS.ToString())\$($Platform.Architecture.LLVMName)\zlibstatic.lib"
+        "$BinaryCache\$($Platform.Triple)\usr\lib\zlibstatic.lib"
       } else {
-        "$LibraryRoot\zlib-1.3.1\usr\lib\$($Platform.OS.ToString())\$($Platform.Architecture.LLVMName)\libz.a"
+        "$BinaryCache\$($Platform.Triple)\usr\lib\libz.a"
       };
-      ZLIB_INCLUDE_DIR = "$LibraryRoot\zlib-1.3.1\usr\include";
+      ZLIB_INCLUDE_DIR = "$BinaryCache\$($Platform.Triple)\usr\include";
       dispatch_DIR = (Get-ProjectCMakeModules $Platform Dispatch);
-      SwiftSyntax_DIR = (Get-ProjectBinaryCache $HostPlatform Compilers);
       _SwiftFoundation_SourceDIR = "$SourceCache\swift-foundation";
       _SwiftFoundationICU_SourceDIR = "$SourceCache\swift-foundation-icu";
       _SwiftCollections_SourceDIR = "$SourceCache\swift-collections";
-      SwiftFoundation_MACRO = "$(Get-ProjectBinaryCache $BuildPlatform FoundationMacros)\bin"
+      SwiftFoundation_MACRO = "$(Get-ProjectBinaryCache $BuildPlatform BootstrapFoundationMacros)\bin"
     }
 }
 
 function Test-Foundation {
+  $ScratchPath = "$BinaryCache\$($BuildPlatform.Triple)\FoundationTests"
+
   # Foundation tests build via swiftpm rather than CMake
   Build-SPMProject `
     -Action Test `
     -Src $SourceCache\swift-foundation `
-    -Bin "$BinaryCache\$($BuildPlatform.Triple)\CoreFoundationTests" `
-    -Platform $BuildPlatform
+    -Bin "$ScratchPath" `
+    -Platform $BuildPlatform `
+    --multiroot-data-file "$SourceCache\swift\utils\build_swift\resources\SwiftPM-Unified-Build.xcworkspace" `
+    --test-product swift-foundationPackageTests
 
   Invoke-IsolatingEnvVars {
-    $env:DISPATCH_INCLUDE_PATH="$(Get-SwiftSDK Windows)/usr/include"
-    $env:LIBXML_LIBRARY_PATH="$LibraryRoot/libxml2-2.11.5/usr/lib/windows/$($BuildPlatform.Architecture.LLVMName)"
-    $env:LIBXML_INCLUDE_PATH="$LibraryRoot/libxml2-2.11.5/usr/include/libxml2"
-    $env:ZLIB_LIBRARY_PATH="$LibraryRoot/zlib-1.3.1/usr/lib/windows/$($BuildPlatform.Architecture.LLVMName)"
-    $env:CURL_LIBRARY_PATH="$LibraryRoot/curl-8.9.1/usr/lib/windows/$($BuildPlatform.Architecture.LLVMName)"
-    $env:CURL_INCLUDE_PATH="$LibraryRoot/curl-8.9.1/usr/include"
+    $env:DISPATCH_INCLUDE_PATH="$(Get-SwiftSDK -OS $BuildPlatform.OS -Identifier $BuildPlatform.DefaultSDK)/usr/include"
+    $env:LIBXML_LIBRARY_PATH="$BinaryCache/$($Platform.Triple)/usr/lib"
+    $env:LIBXML_INCLUDE_PATH="$BinaryCache/$($Platform.Triple)/usr/include/libxml2"
+    $env:ZLIB_LIBRARY_PATH="$BinaryCache/$($Platform.Triple)/usr/lib"
+    $env:CURL_LIBRARY_PATH="$BinaryCache/$($Platform.Triple)/usr/lib"
+    $env:CURL_INCLUDE_PATH="$BinaryCache/$($Platform.Triple)/usr/include"
     Build-SPMProject `
       -Action Test `
       -Src $SourceCache\swift-corelibs-foundation `
-      -Bin "$BinaryCache\$($BuildPlatform.Triple)\FoundationTests" `
+      -Bin "$ScratchPath" `
       -Platform $BuildPlatform `
-      -Configuration $FoundationTestConfiguration
+      --multiroot-data-file "$SourceCache\swift\utils\build_swift\resources\SwiftPM-Unified-Build.xcworkspace" `
+      --test-product swift-corelibs-foundationPackageTests
   }
 }
 
@@ -2429,46 +3057,67 @@ function Build-FoundationMacros([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
     -UseBuiltCompilers Swift `
-    -SwiftSDK (Get-SwiftSDK $Platform.OS) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       SwiftSyntax_DIR = $SwiftSyntaxDir;
     }
 }
 
 function Build-XCTest([Hashtable] $Platform) {
+  $SwiftFlags = if ($Platform.OS -eq [OS]::Windows) {
+    @();
+  } else {
+    @("-I$(Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK)\usr\include");
+  }
+
   Build-CMakeProject `
     -Src $SourceCache\swift-corelibs-xctest `
     -Bin (Get-ProjectBinaryCache $Platform XCTest) `
     -InstallTo "$([IO.Path]::Combine((Get-PlatformRoot $Platform.OS), "Developer", "Library", "XCTest-$ProductVersion", "usr"))" `
     -Platform $Platform `
     -UseBuiltCompilers Swift `
-    -SwiftSDK (Get-SwiftSDK $Platform.OS) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
-      CMAKE_BUILD_WITH_INSTALL_RPATH = "YES";
       CMAKE_INSTALL_BINDIR = $Platform.BinaryDir;
+      CMAKE_Swift_FLAGS = $SwiftFlags;
       ENABLE_TESTING = "NO";
-      dispatch_DIR = $(Get-ProjectCMakeModules $Platform Dispatch);
-      Foundation_DIR = $(Get-ProjectCMakeModules $Platform DynamicFoundation);
       XCTest_INSTALL_NESTED_SUBDIR = "YES";
     }
 }
 
 function Test-XCTest {
   Invoke-IsolatingEnvVars {
-    $env:Path = "$(Get-ProjectBinaryCache $BuildPlatform XCTest);$(Get-ProjectBinaryCache $BuildPlatform DynamicFoundation)\bin;$(Get-ProjectBinaryCache $BuildPlatform Dispatch);$(Get-ProjectBinaryCache $BuildPlatform Runtime)\bin;${env:Path};$UnixToolsBinDir"
+    $SwiftRuntime = if ($BuildPlatform.DefaultSDK -match "Experimental") {
+      [IO.Path]::Combine((Get-InstallDir $BuildPlatform), "Runtimes", "$ProductVersion.experimental");
+    } else {
+      [IO.Path]::Combine((Get-InstallDir $BuildPlatform), "Runtimes", "$ProductVersion");
+    }
+
+    $DispatchBinaryCache = if ($BuildPlatform.DefaultSDK -match "Experimental") {
+      Get-ProjectBinaryCache $BuildPlatform ExperimentalDynamicDispatch
+    } else {
+      Get-ProjectBinaryCache $BuildPlatform Dispatch
+    }
+
+    $FoundationBinaryCache = if ($BuildPlatform.DefaultSDK -match "Experimental") {
+      Get-ProjectBinaryCache $BuildPlatform ExperimentalDynamicFoundation
+    } else {
+      Get-ProjectBinaryCache $BuildPlatform DynamicFoundation
+    }
+
+    $env:Path = "$(Get-ProjectBinaryCache $BuildPlatform XCTest);${FoundationBinaryCache}\bin;${DispatchBinaryCache};${SwiftRuntime}\usr\bin;${env:Path};$UnixToolsBinDir"
+    $env:SDKROOT = Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK
 
     Build-CMakeProject `
       -Src $SourceCache\swift-corelibs-xctest `
       -Bin (Get-ProjectBinaryCache $BuildPlatform XCTest) `
       -Platform $BuildPlatform `
-      -UseBuiltCompilers Swift `
+      -UseBuiltCompilers C,CXX,Swift `
+      -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
       -BuildTargets default,check-xctest `
       -Defines @{
-        CMAKE_BUILD_WITH_INSTALL_RPATH = "YES";
         ENABLE_TESTING = "YES";
-        dispatch_DIR = $(Get-ProjectCMakeModules $BuildPlatform Dispatch);
-        Foundation_DIR = $(Get-ProjectCMakeModules $BuildPlatform DynamicFoundation);
         LLVM_DIR = "$(Get-ProjectBinaryCache $BuildPlatform LLVM)\lib\cmake\llvm";
         XCTEST_PATH_TO_FOUNDATION_BUILD = $(Get-ProjectBinaryCache $BuildPlatform DynamicFoundation);
         XCTEST_PATH_TO_LIBDISPATCH_BUILD = $(Get-ProjectBinaryCache $BuildPlatform Dispatch);
@@ -2478,21 +3127,24 @@ function Test-XCTest {
 }
 
 function Build-Testing([Hashtable] $Platform) {
+  $SwiftFlags = if ($Platform.OS -eq [OS]::Windows) {
+    @();
+  } else {
+    @("-I$(Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK)\usr\include");
+  }
+
   Build-CMakeProject `
     -Src $SourceCache\swift-testing `
     -Bin (Get-ProjectBinaryCache $Platform Testing) `
     -InstallTo "$([IO.Path]::Combine((Get-PlatformRoot $Platform.OS), "Developer", "Library", "Testing-$ProductVersion", "usr"))" `
     -Platform $Platform `
-    -UseBuiltCompilers C,CXX,Swift `
-    -SwiftSDK (Get-SwiftSDK $Platform.OS) `
+    -UseBuiltCompilers CXX,Swift `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
-      CMAKE_BUILD_WITH_INSTALL_RPATH = "YES";
       CMAKE_INSTALL_BINDIR = $Platform.BinaryDir;
-      dispatch_DIR = (Get-ProjectCMakeModules $Platform Dispatch);
-      Foundation_DIR = (Get-ProjectCMakeModules $Platform DynamicFoundation);
-      SwiftSyntax_DIR = (Get-ProjectBinaryCache $HostPlatform Compilers);
-      SwiftTesting_MACRO = "$(Get-ProjectBinaryCache $BuildPlatform TestingMacros)\TestingMacros.dll";
+      CMAKE_Swift_FLAGS = $SwiftFlags;
+      SwiftTesting_MACRO = "$(Get-ProjectBinaryCache $BuildPlatform BootstrapTestingMacros)\TestingMacros.dll";
       SwiftTesting_INSTALL_NESTED_SUBDIR = "YES";
     }
 }
@@ -2501,50 +3153,184 @@ function Test-Testing {
   throw "testing Testing is not supported"
 }
 
-function Write-PlatformInfoPlist([Hashtable] $Platform) {
+function Write-PlatformInfoPlist([OS] $OS) {
   $Settings = @{
     DefaultProperties = @{
       SWIFT_TESTING_VERSION = "$ProductVersion"
       XCTEST_VERSION = "$ProductVersion"
     }
   }
-  if ($Platform.OS -eq [OS]::Windows) {
+  if ($OS -eq [OS]::Windows) {
     $Settings.DefaultProperties.SWIFTC_FLAGS = @( "-use-ld=lld" )
   }
 
-  Write-PList -Settings $Settings -Path "$(Get-PlatformRoot $Platform.OS)\Info.plist"
+  Write-PList -Settings $Settings -Path "$(Get-PlatformRoot $OS)\Info.plist"
 }
 
 # Copies files installed by CMake from the arch-specific platform root,
 # where they follow the layout expected by the installer,
 # to the final platform root, following the installer layout.
-function Install-Platform([Hashtable[]] $Platforms, [OS] $OS) {
+function Install-SDK([Hashtable[]] $Platforms, [OS] $OS = $Platforms[0].OS, [string] $Identifier = $OS.ToString()) {
   # Copy SDK header files
   foreach ($Module in ("Block", "dispatch", "os", "_foundation_unicode", "_FoundationCShims")) {
-    $ModuleDirectory = "$(Get-SwiftSDK $OS)\usr\lib\swift\$Module"
-    if (Test-Path $ModuleDirectory) {
-      Move-Directory $ModuleDirectory "$(Get-SwiftSDK $OS)\usr\include\"
+    foreach ($ResourceType in ("swift", "swift_static")) {
+      $ModuleDirectory = "$(Get-SwiftSDK -OS $OS -Identifier $Identifier)\usr\lib\$ResourceType\$Module"
+      if (Test-Path $ModuleDirectory) {
+        Move-Directory $ModuleDirectory "$(Get-SwiftSDK -OS $OS -Identifier $Identifier)\usr\include\"
+      }
     }
   }
 
   # Copy files from the arch subdirectory, including "*.swiftmodule" which need restructuring
   foreach ($Platform in $Platforms) {
-    $PlatformResources = "$(Get-SwiftSDK $Platform.OS)\usr\lib\swift\$($Platform.OS.ToString().ToLowerInvariant())"
-    Get-ChildItem -Recurse "$PlatformResources\$($Platform.Architecture.LLVMName)" | ForEach-Object {
-      if (".swiftmodule", ".swiftdoc", ".swiftinterface" -contains $_.Extension) {
-        Copy-File $_.FullName "$PlatformResources\$($_.BaseName).swiftmodule\$(Get-ModuleTriple $Platform)$($_.Extension)"
+    foreach ($ResourceType in ("swift", "swift_static")) {
+      $PlatformResources = "$(Get-SwiftSDK -OS $OS -Identifier $Identifier)\usr\lib\$ResourceType\$($OS.ToString().ToLowerInvariant())"
+      Get-ChildItem -ErrorAction SilentlyContinue -Recurse "$PlatformResources\$($Platform.Architecture.LLVMName)" | ForEach-Object {
+        if (".swiftmodule", ".swiftdoc", ".swiftinterface" -contains $_.Extension) {
+          Write-Host -BackgroundColor DarkRed -ForegroundColor White "$($_.FullName) is not in a thick module layout"
+          Copy-File $_.FullName "$PlatformResources\$($_.BaseName).swiftmodule\$(Get-ModuleTriple $Platform)$($_.Extension)"
+        }
       }
     }
   }
 }
 
+function Build-SDK([Hashtable] $Platform) {
+  # Third Party Dependencies
+  Invoke-BuildStep Build-LLVM $Platform
+
+  # Libraries
+  Invoke-BuildStep Build-Runtime $Platform
+  Invoke-BuildStep Build-Dispatch $Platform
+  Invoke-BuildStep Build-Foundation $Platform
+}
+
+function Build-ExperimentalSDK([Hashtable] $Platform) {
+  Invoke-BuildStep Build-CDispatch $Platform
+
+  if ($Platform.LinkModes.Contains("dynamic")) {
+    Invoke-BuildStep Build-ExperimentalRuntime $Platform
+  }
+  if ($Platform.LinkModes.Contains("static")) {
+    Invoke-BuildStep Build-ExperimentalRuntime $Platform -Static
+  }
+
+  $SDKROOT = Get-SwiftSDK -OS $Platform.OS -Identifier "$($Platform.OS)Experimental"
+
+  if ($Platform.LinkModes.Contains("dynamic")) {
+    Record-OperationTime $Platform "Build-ExperimentalDynamicDispatch" {
+      Build-CMakeProject `
+        -Src $SourceCache\swift-corelibs-libdispatch `
+        -Bin (Get-ProjectBinaryCache $Platform ExperimentalDynamicDispatch) `
+        -InstallTo "${SDKROOT}\usr" `
+        -Platform $Platform `
+        -UseBuiltCompilers C,CXX,Swift `
+        -SwiftSDK "${SDKROOT}" `
+        -Defines @{
+          BUILD_SHARED_LIBS = "YES";
+          CMAKE_FIND_PACKAGE_PREFER_CONFIG = "YES";
+          CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+
+          ENABLE_SWIFT = "YES";
+        }
+    }
+
+    Record-OperationTime $Platform "Build-ExperimentalDynamicFoundation" {
+      Build-CMakeProject `
+        -Src $SourceCache\swift-corelibs-foundation `
+        -Bin (Get-ProjectBinaryCache $Platform ExperimentalDynamicFoundation) `
+        -InstallTo "${SDKROOT}\usr" `
+        -Platform $Platform `
+        -UseBuiltCompilers ASM,C,CXX,Swift `
+        -SwiftSDK "${SDKROOT}" `
+        -Defines @{
+          BUILD_SHARED_LIBS = "YES";
+          CMAKE_FIND_PACKAGE_PREFER_CONFIG = "YES";
+          CMAKE_NINJA_FORCE_RESPONSE_FILE = "YES";
+          CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+          ENABLE_TESTING = "NO";
+
+          FOUNDATION_BUILD_TOOLS = if ($Platform.OS -eq [OS]::Windows) { "YES" } else { "NO" };
+          CURL_DIR = "$BinaryCache\$($Platform.Triple)\usr\lib\cmake\CURL";
+          LibXml2_DIR = "$BinaryCache\$($Platform.Triple)\usr\lib\cmake\libxml2-2.11.5";
+          ZLIB_INCLUDE_DIR = "$BinaryCache\$($Platform.Triple)\usr\include";
+          ZLIB_LIBRARY = if ($Platform.OS -eq [OS]::Windows) {
+            "$BinaryCache\$($Platform.Triple)\usr\lib\zlibstatic.lib"
+          } else {
+            "$BinaryCache\$($Platform.Triple)\usr\lib\libz.a"
+          };
+          dispatch_DIR = $(Get-ProjectCMakeModules $Platform ExperimentalDynamicDispatch);
+          SwiftSyntax_DIR = (Get-ProjectBinaryCache $HostPlatform Compilers);
+          _SwiftFoundation_SourceDIR = "$SourceCache\swift-foundation";
+          _SwiftFoundationICU_SourceDIR = "$SourceCache\swift-foundation-icu";
+          _SwiftCollections_SourceDIR = "$SourceCache\swift-collections";
+          SwiftFoundation_MACRO = "$(Get-ProjectBinaryCache $BuildPlatform BootstrapFoundationMacros)\bin"
+        }
+    }
+  }
+
+  if ($Platform.LinkModes.Contains("static")) {
+    Record-OperationTime $Platform "Build-ExperimentalStaticDispatch" {
+      Build-CMakeProject `
+        -Src $SourceCache\swift-corelibs-libdispatch `
+        -Bin (Get-ProjectBinaryCache $Platform ExperimentalStaticDispatch) `
+        -InstallTo "${SDKROOT}\usr" `
+        -Platform $Platform `
+        -UseBuiltCompilers C,CXX,Swift `
+        -SwiftSDK "${SDKROOT}" `
+        -Defines @{
+          BUILD_SHARED_LIBS = "NO";
+          CMAKE_Swift_FLAGS = @("-static-stdlib", "-Xfrontend", "-use-static-resource-dir");
+          CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+
+          ENABLE_SWIFT = "YES";
+        }
+    }
+
+    Record-OperationTime $Platform "Build-ExperimentalStaticFoundation" {
+      Build-CMakeProject `
+        -Src $SourceCache\swift-corelibs-foundation `
+        -Bin (Get-ProjectBinaryCache $Platform ExperimentalStaticFoundation) `
+        -InstallTo "${SDKROOT}\usr" `
+        -Platform $Platform `
+        -UseBuiltCompilers ASM,C,CXX,Swift `
+        -SwiftSDK ${SDKROOT} `
+        -Defines @{
+          BUILD_SHARED_LIBS = "NO";
+          CMAKE_FIND_PACKAGE_PREFER_CONFIG = "YES";
+          CMAKE_NINJA_FORCE_RESPONSE_FILE = "YES";
+          CMAKE_Swift_FLAGS = @("-static-stdlib", "-Xfrontend", "-use-static-resource-dir");
+          CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+          ENABLE_TESTING = "NO";
+
+          FOUNDATION_BUILD_TOOLS = if ($Platform.OS -eq [OS]::Windows) { "YES" } else { "NO" };
+          CURL_DIR = "$BinaryCache\$($Platform.Triple)\usr\lib\cmake\CURL";
+          LibXml2_DIR = "$BinaryCache\$($Platform.Triple)\usr\lib\cmake\libxml2-2.11.5";
+          ZLIB_INCLUDE_DIR = "$BinaryCache\$($Platform.Triple)\usr\include";
+          ZLIB_LIBRARY = if ($Platform.OS -eq [OS]::Windows) {
+            "$BinaryCache\$($Platform.Triple)\usr\lib\zlibstatic.lib"
+          } else {
+            "$BinaryCache\$($Platform.Triple)\usr\lib\libz.a"
+          };
+          dispatch_DIR = $(Get-ProjectCMakeModules $Platform ExperimentalStaticDispatch);
+          SwiftSyntax_DIR = (Get-ProjectBinaryCache $HostPlatform Compilers);
+          _SwiftFoundation_SourceDIR = "$SourceCache\swift-foundation";
+          _SwiftFoundationICU_SourceDIR = "$SourceCache\swift-foundation-icu";
+          _SwiftCollections_SourceDIR = "$SourceCache\swift-collections";
+          SwiftFoundation_MACRO = "$(Get-ProjectBinaryCache $BuildPlatform BootstrapFoundationMacros)\bin"
+        }
+      }
+    }
+}
+
 function Build-SQLite([Hashtable] $Platform) {
   Build-CMakeProject `
     -Src $SourceCache\swift-toolchain-sqlite `
-    -Bin "$BinaryCache\$($Platform.Triple)\sqlite-3.46.0" `
-    -InstallTo $LibraryRoot\sqlite-3.46.0\usr `
+    -Bin (Get-ProjectBinaryCache $Platform SQLite) `
     -Platform $Platform `
-    -UseMSVCCompilers C `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("C") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("C") }) `
+    -BuildTargets default `
     -Defines @{
       BUILD_SHARED_LIBS = "NO";
     }
@@ -2556,7 +3342,7 @@ function Build-System([Hashtable] $Platform) {
     -Bin (Get-ProjectBinaryCache $Platform System) `
     -Platform $Platform `
     -UseBuiltCompilers C,Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -BuildTargets default `
     -Defines @{
       BUILD_SHARED_LIBS = "NO";
@@ -2564,6 +3350,19 @@ function Build-System([Hashtable] $Platform) {
     }
 }
 
+function Build-Subprocess([Hashtable] $Platform) {
+  Build-CMakeProject `
+    -Src $sourceCache\swift-subprocess `
+    -Bin (Get-ProjectBinaryCache $Platform Subprocess) `
+    -Platform $Platform `
+    -UseBuiltCompilers C,Swift `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
+    -Defines @{
+      BUILD_SHARED_LIBS = "NO";
+      CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+    }
+}
+
 function Build-Build([Hashtable] $Platform) {
   # Use lld to workaround the ARM64 LNK1322 issue: https://github.com/swiftlang/swift/issues/79740
   # FIXME(hjyamauchi) Have a real fix
@@ -2575,7 +3374,7 @@ function Build-Build([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
     -UseBuiltCompilers C,CXX,Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines (@{
       BUILD_SHARED_LIBS = "YES";
       CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
@@ -2584,8 +3383,8 @@ function Build-Build([Hashtable] $Platform) {
       SwiftDriver_DIR = (Get-ProjectCMakeModules $Platform Driver);
       SwiftSystem_DIR = (Get-ProjectCMakeModules $Platform System);
       TSC_DIR = (Get-ProjectCMakeModules $Platform ToolsSupportCore);
-      SQLite3_INCLUDE_DIR = "$LibraryRoot\sqlite-3.46.0\usr\include";
-      SQLite3_LIBRARY = "$LibraryRoot\sqlite-3.46.0\usr\lib\SQLite3.lib";
+      SQLite3_INCLUDE_DIR = "$SourceCache\swift-toolchain-sqlite\Sources\CSQLite\include";
+      SQLite3_LIBRARY = "$(Get-ProjectBinaryCache $Platform SQLite)\SQLite3.lib";
     } + $ArchSpecificOptions)
 }
 
@@ -2596,10 +3395,13 @@ function Build-ToolsSupportCore([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
     -UseBuiltCompilers C,Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
       CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+
+      Foundation_DIR = $(Get-ProjectCMakeModules $Platform DynamicFoundation);
+      XCTest_DIR = (Get-ProjectCMakeModules $Platform XCTest);
     }
 }
 
@@ -2609,14 +3411,15 @@ function Build-LLBuild([Hashtable] $Platform) {
     -Bin (Get-ProjectBinaryCache $Platform LLBuild) `
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
-    -UseMSVCCompilers CXX `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("CXX") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("CXX") }) `
     -UseBuiltCompilers Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
       LLBUILD_SUPPORT_BINDINGS = "Swift";
-      SQLite3_INCLUDE_DIR = "$LibraryRoot\sqlite-3.46.0\usr\include";
-      SQLite3_LIBRARY = "$LibraryRoot\sqlite-3.46.0\usr\lib\SQLite3.lib";
+      SQLite3_INCLUDE_DIR = "$SourceCache\swift-toolchain-sqlite\Sources\CSQLite\include";
+      SQLite3_LIBRARY = "$(Get-ProjectBinaryCache $Platform SQLite)\SQLite3.lib";
     }
 }
 
@@ -2624,7 +3427,7 @@ function Test-LLBuild {
   # Build additional llvm executables needed by tests
   Invoke-IsolatingEnvVars {
     Invoke-VsDevShell $BuildPlatform
-    Invoke-Program ninja.exe -C (Get-ProjectBinaryCache $BuildPlatform BuildTools) FileCheck not
+    Invoke-Program $ninja -C (Get-ProjectBinaryCache $BuildPlatform BuildTools) FileCheck not
   }
 
   Invoke-IsolatingEnvVars {
@@ -2636,17 +3439,18 @@ function Test-LLBuild {
       -Src $SourceCache\llbuild `
       -Bin (Get-ProjectBinaryCache $BuildPlatform LLBuild) `
       -Platform $Platform `
-      -UseMSVCCompilers CXX `
+      -UseMSVCCompilers $(if ($UseHostToolchain) { @("CXX") } else { @("") }) `
+      -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("CXX") }) `
       -UseBuiltCompilers Swift `
-      -SwiftSDK (Get-SwiftSDK Windows) `
+      -SwiftSDK (Get-SwiftSDK -OS $BuildPlatform.OS -Identifier $BuildPlatform.DefaultSDK) `
       -BuildTargets default,test-llbuild `
       -Defines = @{
         BUILD_SHARED_LIBS = "YES";
         FILECHECK_EXECUTABLE = ([IO.Path]::Combine((Get-ProjectBinaryCache $BuildPlatform BuildTools), "bin", "FileCheck.exe"));
         LIT_EXECUTABLE = "$SourceCache\llvm-project\llvm\utils\lit\lit.py";
         LLBUILD_SUPPORT_BINDINGS = "Swift";
-        SQLite3_INCLUDE_DIR = "$LibraryRoot\sqlite-3.46.0\usr\include";
-        SQLite3_LIBRARY = "$LibraryRoot\sqlite-3.46.0\usr\lib\SQLite3.lib";
+        SQLite3_INCLUDE_DIR = "$SourceCache\swift-toolchain-sqlite\Sources\CSQLite\include";
+        SQLite3_LIBRARY = "$(Get-ProjectBinaryCache $Platform SQLite)\SQLite3.lib";
       }
   }
 }
@@ -2658,7 +3462,7 @@ function Build-ArgumentParser([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
     -UseBuiltCompilers Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
       BUILD_TESTING = "NO";
@@ -2673,15 +3477,15 @@ function Build-Driver([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
     -UseBuiltCompilers C,CXX,Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
       CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
       TSC_DIR = (Get-ProjectCMakeModules $Platform ToolsSupportCore);
       LLBuild_DIR = (Get-ProjectCMakeModules $Platform LLBuild);
       ArgumentParser_DIR = (Get-ProjectCMakeModules $Platform ArgumentParser);
-      SQLite3_INCLUDE_DIR = "$LibraryRoot\sqlite-3.46.0\usr\include";
-      SQLite3_LIBRARY = "$LibraryRoot\sqlite-3.46.0\usr\lib\SQLite3.lib";
+      SQLite3_INCLUDE_DIR = "$SourceCache\swift-toolchain-sqlite\Sources\CSQLite\include";
+      SQLite3_LIBRARY = "$(Get-ProjectBinaryCache $Platform SQLite)\SQLite3.lib";
       SWIFT_DRIVER_BUILD_TOOLS = "YES";
       LLVM_DIR = "$(Get-ProjectBinaryCache $Platform Compilers)\lib\cmake\llvm";
       Clang_DIR = "$(Get-ProjectBinaryCache $Platform Compilers)\lib\cmake\clang";
@@ -2694,12 +3498,13 @@ function Build-Crypto([Hashtable] $Platform) {
     -Src $SourceCache\swift-crypto `
     -Bin (Get-ProjectBinaryCache $Platform Crypto) `
     -Platform $Platform `
-    -UseBuiltCompilers Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -UseBuiltCompilers ASM, C, CXX, Swift `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -BuildTargets default `
     -Defines @{
       BUILD_SHARED_LIBS = "NO";
       CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
+      SwiftASN1_DIR = (Get-ProjectCMakeModules $Platform ASN1);
     }
 }
 
@@ -2710,7 +3515,7 @@ function Build-Collections([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
     -UseBuiltCompilers C,Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
       CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
@@ -2723,7 +3528,7 @@ function Build-ASN1([Hashtable] $Platform) {
     -Bin (Get-ProjectBinaryCache $Platform ASN1) `
     -Platform $Platform `
     -UseBuiltCompilers Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -BuildTargets default `
     -Defines @{
       BUILD_SHARED_LIBS = "NO";
@@ -2737,7 +3542,7 @@ function Build-Certificates([Hashtable] $Platform) {
     -Bin (Get-ProjectBinaryCache $Platform Certificates) `
     -Platform $Platform `
     -UseBuiltCompilers Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -BuildTargets default `
     -Defines @{
       BUILD_SHARED_LIBS = "NO";
@@ -2760,7 +3565,7 @@ function Build-PackageManager([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
     -UseBuiltCompilers C,Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
       CMAKE_Swift_FLAGS = @("-DCRYPTO_v2");
@@ -2770,13 +3575,35 @@ function Build-PackageManager([Hashtable] $Platform) {
       LLBuild_DIR = (Get-ProjectCMakeModules $Platform LLBuild);
       ArgumentParser_DIR = (Get-ProjectCMakeModules $Platform ArgumentParser);
       SwiftDriver_DIR = (Get-ProjectCMakeModules $Platform Driver);
+      SwiftBuild_DIR = (Get-ProjectCMakeModules $Platform Build);
       SwiftCrypto_DIR = (Get-ProjectCMakeModules $Platform Crypto);
       SwiftCollections_DIR = (Get-ProjectCMakeModules $Platform Collections);
       SwiftASN1_DIR = (Get-ProjectCMakeModules $Platform ASN1);
       SwiftCertificates_DIR = (Get-ProjectCMakeModules $Platform Certificates);
       SwiftSyntax_DIR = (Get-ProjectCMakeModules $Platform Compilers);
-      SQLite3_INCLUDE_DIR = "$LibraryRoot\sqlite-3.46.0\usr\include";
-      SQLite3_LIBRARY = "$LibraryRoot\sqlite-3.46.0\usr\lib\SQLite3.lib";
+      SQLite3_INCLUDE_DIR = "$SourceCache\swift-toolchain-sqlite\Sources\CSQLite\include";
+      SQLite3_LIBRARY = "$(Get-ProjectBinaryCache $Platform SQLite)\SQLite3.lib";
+    }
+}
+
+function Build-PackageManagerRuntime([Hashtable] $Platform) {
+  $SrcDir = if (Test-Path -Path "$SourceCache\swift-package-manager" -PathType Container) {
+    "$SourceCache\swift-package-manager"
+  } else {
+    "$SourceCache\swiftpm"
+  }
+
+  Build-CMakeProject `
+    -Src $SrcDir\Sources\Runtimes `
+    -Bin (Get-ProjectBinaryCache $Platform PackageManagerRuntime) `
+    -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
+    -Platform $Platform `
+    -UseBuiltCompilers C,CXX,Swift `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
+    -UseGNUDriver `
+    -Defines @{
+      BUILD_SHARED_LIBS = "YES";
+      SwiftPM_ENABLE_RUNTIME = "NO";
     }
 }
 
@@ -2787,7 +3614,7 @@ function Build-Markdown([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
     -UseBuiltCompilers C,Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "NO";
       CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
@@ -2802,9 +3629,10 @@ function Build-Format([Hashtable] $Platform) {
     -Bin (Get-ProjectBinaryCache $Platform Format) `
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
-    -UseMSVCCompilers C `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("C") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("C") }) `
     -UseBuiltCompilers Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       BUILD_SHARED_LIBS = "YES";
       ArgumentParser_DIR = (Get-ProjectCMakeModules $Platform ArgumentParser);
@@ -2857,23 +3685,25 @@ function Build-LMDB([Hashtable] $Platform) {
     -Src $SourceCache\swift-lmdb `
     -Bin (Get-ProjectBinaryCache $Platform LMDB) `
     -Platform $Platform `
-    -UseMSVCCompilers C `
+    -UseMSVCCompilers $(if ($UseHostToolchain) { @("C") } else { @("") }) `
+    -UsePinnedCompilers $(if ($UseHostToolchain) { @("") } else { @("C") }) `
     -BuildTargets default
 }
 
 function Build-IndexStoreDB([Hashtable] $Platform) {
+  $SDKROOT = Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK
   Build-CMakeProject `
     -Src $SourceCache\indexstore-db `
     -Bin (Get-ProjectBinaryCache $Platform IndexStoreDB) `
     -Platform $Platform `
     -UseBuiltCompilers C,CXX,Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK $SDKROOT `
     -BuildTargets default `
     -Defines @{
       BUILD_SHARED_LIBS = "NO";
       CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
-      CMAKE_C_FLAGS = @("-I$(Get-SwiftSDK Windows)\usr\include", "-I$(Get-SwiftSDK Windows)\usr\include\Block");
-      CMAKE_CXX_FLAGS = @("-I$(Get-SwiftSDK Windows)\usr\include", "-I$(Get-SwiftSDK Windows)\usr\include\Block");
+      CMAKE_C_FLAGS = @("-I$SDKROOT\usr\include", "-I$SDKROOT\usr\include\Block");
+      CMAKE_CXX_FLAGS = @("-I$SDKROOT\usr\include", "-I$SDKROOT\usr\include\Block");
       LMDB_DIR = (Get-ProjectCMakeModules $Platform LMDB);
     }
 }
@@ -2885,15 +3715,17 @@ function Build-SourceKitLSP([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr" `
     -Platform $Platform `
     -UseBuiltCompilers C,Swift `
-    -SwiftSDK (Get-SwiftSDK Windows) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       CMAKE_STATIC_LIBRARY_PREFIX_Swift = "lib";
       SwiftSyntax_DIR = (Get-ProjectCMakeModules $Platform Compilers);
       TSC_DIR = (Get-ProjectCMakeModules $Platform ToolsSupportCore);
       LLBuild_DIR = (Get-ProjectCMakeModules $Platform LLBuild);
       ArgumentParser_DIR = (Get-ProjectCMakeModules $Platform ArgumentParser);
+      SwiftASN1_DIR = (Get-ProjectCMakeModules $Platform ASN1);
       SwiftCrypto_DIR = (Get-ProjectCMakeModules $Platform Crypto);
       SwiftCollections_DIR = (Get-ProjectCMakeModules $Platform Collections);
+      SwiftBuild_DIR = (Get-ProjectCMakeModules $Platform Build);
       SwiftPM_DIR = (Get-ProjectCMakeModules $Platform PackageManager);
       LMDB_DIR = (Get-ProjectCMakeModules $Platform LMDB);
       IndexStoreDB_DIR = (Get-ProjectCMakeModules $Platform IndexStoreDB);
@@ -2931,7 +3763,10 @@ function Test-SourceKitLSP {
     # swift-crypto
     "-Xswiftc", "-I$(Get-ProjectBinaryCache $BuildPlatform Crypto)\swift",
     "-Xlinker", "-L$(Get-ProjectBinaryCache $BuildPlatform Crypto)\lib",
-    "-Xlinker", "$(Get-ProjectBinaryCache $BuildPlatform Crypto)\lib\CCryptoBoringSSL.lib",
+    "-Xlinker", "$(Get-ProjectBinaryCache $BuildPlatform Crypto)\lib\libCCryptoBoringSSL.lib",
+    # swift-asn1
+    "-Xswiftc", "-I$(Get-ProjectBinaryCache $BuildPlatform ASN1)\swift",
+    "-Xlinker", "-L$(Get-ProjectBinaryCache $BuildPlatform ASN1)\lib",
     # swift-package-manager
     "-Xswiftc", "-I$(Get-ProjectBinaryCache $BuildPlatform PackageManager)\swift",
     "-Xlinker", "-L$(Get-ProjectBinaryCache $BuildPlatform PackageManager)\lib",
@@ -2992,7 +3827,7 @@ function Build-TestingMacros([Hashtable] $Platform) {
     -InstallTo "$($Platform.ToolchainInstallRoot)\usr"  `
     -Platform $Platform `
     -UseBuiltCompilers Swift `
-    -SwiftSDK (Get-SwiftSDK $Platform.OS) `
+    -SwiftSDK (Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK) `
     -Defines @{
       SwiftSyntax_DIR = (Get-ProjectCMakeModules $Platform Compilers);
     }
@@ -3006,16 +3841,20 @@ function Install-HostToolchain() {
 
   # Restructure _InternalSwiftScan (keep the original one for the installer)
   Copy-Item -Force `
-    "$($HostPlatform.ToolchainInstallRoot)\usr\lib\swift\_InternalSwiftScan" `
-    "$($HostPlatform.ToolchainInstallRoot)\usr\include"
+    -Path "$($HostPlatform.ToolchainInstallRoot)\usr\lib\swift\_InternalSwiftScan" `
+    -Destination "$($HostPlatform.ToolchainInstallRoot)\usr\include"
   Copy-Item -Force `
-    "$($HostPlatform.ToolchainInstallRoot)\usr\lib\swift\windows\_InternalSwiftScan.lib" `
-    "$($HostPlatform.ToolchainInstallRoot)\usr\lib"
+    -Path "$($HostPlatform.ToolchainInstallRoot)\usr\lib\swift\windows\_InternalSwiftScan.lib" `
+    -Destination "$($HostPlatform.ToolchainInstallRoot)\usr\lib"
 
   # Switch to swift-driver
   $SwiftDriver = ([IO.Path]::Combine((Get-ProjectBinaryCache $HostPlatform Driver), "bin", "swift-driver.exe"))
-  Copy-Item -Force $SwiftDriver "$($HostPlatform.ToolchainInstallRoot)\usr\bin\swift.exe"
-  Copy-Item -Force $SwiftDriver "$($HostPlatform.ToolchainInstallRoot)\usr\bin\swiftc.exe"
+  Copy-Item -Force `
+    -Path $SwiftDriver `
+    -Destination "$($HostPlatform.ToolchainInstallRoot)\usr\bin\swift.exe"
+  Copy-Item -Force `
+    -Path $SwiftDriver `
+    -Destination "$($HostPlatform.ToolchainInstallRoot)\usr\bin\swiftc.exe"
 }
 
 function Build-Inspect([Hashtable] $Platform) {
@@ -3032,19 +3871,21 @@ function Build-Inspect([Hashtable] $Platform) {
     $InstallPath = "$(Get-PlatformRoot $Platform.OS)\Developer\Library\$(Get-ModuleTriple $Platform)"
   }
 
+  $SDKROOT = Get-SwiftSDK -OS $Platform.OS -Identifier $Platform.DefaultSDK
+
   Build-CMakeProject `
     -Src $SourceCache\swift\tools\swift-inspect `
     -Bin (Get-ProjectBinaryCache $Platform SwiftInspect)`
     -InstallTo $InstallPath `
     -Platform $Platform `
     -UseBuiltCompilers C,CXX,Swift `
-    -SwiftSDK (Get-SwiftSDK $Platform.OS) `
+    -SwiftSDK $SDKROOT `
     -Defines @{
       CMAKE_Swift_FLAGS = @(
-        "-Xcc", "-I$(Get-SwiftSDK $Platform.OS)\usr\include",
-        "-Xcc", "-I$(Get-SwiftSDK $Platform.OS)\usr\lib\swift",
-        "-Xcc", "-I$(Get-SwiftSDK $Platform.OS)\usr\include\swift\SwiftRemoteMirror",
-        "-L$(Get-SwiftSDK $Platform.OS)\usr\lib\swift\$($Platform.OS.ToString())\$($Platform.Architecture.LLVMName)"
+        "-Xcc", "-I$SDKROOT\usr\include",
+        "-Xcc", "-I$SDKROOT\usr\lib\swift",
+        "-Xcc", "-I$SDKROOT\usr\include\swift\SwiftRemoteMirror",
+        "-L$SDKROOT\usr\lib\swift\$($Platform.OS.ToString())\$($Platform.Architecture.LLVMName)"
       );
       ArgumentParser_DIR = $ArgumentParserDir;
     }
@@ -3071,20 +3912,19 @@ function Test-PackageManager() {
     -Src $SrcDir `
     -Bin "$BinaryCache\$($HostPlatform.Triple)\PackageManagerTests" `
     -Platform $HostPlatform `
-    -Xcc "-I$LibraryRoot\sqlite-3.46.0\usr\include" -Xlinker "-L$LibraryRoot\sqlite-3.46.0\usr\lib"
+    -Xcc "-I$(Get-InstallDir $Platform)\Toolchains\$ProductVersion+Asserts\usr\include" `
+    -Xlinker "-L$(Get-InstallDir $Platform)\Toolchains\$ProductVersion+Asserts\usr\lib"
 }
 
 function Build-Installer([Hashtable] $Platform) {
   # TODO(hjyamauchi) Re-enable the swift-inspect and swift-docc builds
   # when cross-compiling https://github.com/apple/swift/issues/71655
-  $INCLUDE_SWIFT_DOCC = if ($IsCrossCompiling) { "false" } else { "true" }
+  $INCLUDE_SWIFT_DOCC = if ($IsCrossCompiling) { "False" } else { "True" }
 
   $Properties = @{
     BundleFlavor = "offline";
-    TOOLCHAIN_ROOT = "$($Platform.ToolchainInstallRoot)\";
-    # When cross-compiling, bundle the second mimalloc redirect dll as a workaround for
-    # https://github.com/microsoft/mimalloc/issues/997
-    WORKAROUND_MIMALLOC_ISSUE_997 = if ($IsCrossCompiling) { "true" } else { "false" };
+    ImageRoot = "$(Get-InstallDir $Platform)\";
+    IncludeLegacySDK = if ($HostPlatform.DefaultSDK -match "Experimental") { "False" } else { "True" };
     INCLUDE_SWIFT_DOCC = $INCLUDE_SWIFT_DOCC;
     SWIFT_DOCC_BUILD = "$(Get-ProjectBinaryCache $HostPlatform DocC)\release";
     SWIFT_DOCC_RENDER_ARTIFACT_ROOT = "${SourceCache}\swift-docc-render-artifact";
@@ -3099,10 +3939,18 @@ function Build-Installer([Hashtable] $Platform) {
     }
   }
 
-  foreach ($SDKPlatform in $WindowsSDKPlatforms) {
-    $Properties["INCLUDE_WINDOWS_$($SDKPlatform.Architecture.VSName.ToUpperInvariant())_SDK"] = "true"
-    $Properties["PLATFORM_ROOT_$($SDKPlatform.Architecture.VSName.ToUpperInvariant())"] = "$(Get-PlatformRoot Windows)\";
-    $Properties["SDK_ROOT_$($SDKPlatform.Architecture.VSName.ToUpperInvariant())"] = "$(Get-SwiftSDK Windows)\"
+  $Properties["Platforms"] = "`"$(
+    @(
+      if ($Windows) { "windows" }
+      if ($Android) { "android" }
+    ) -Join ";"
+  )`"";
+  $Properties["AndroidArchitectures"] = "`"$(($AndroidSDKBuilds | ForEach-Object { $_.Architecture.LLVMName }) -Join ";")`""
+  $Properties["WindowsArchitectures"] = "`"$(($WindowsSDKBuilds | ForEach-Object { $_.Architecture.LLVMName }) -Join ";")`""
+  $Properties["ToolchainVariants"] = "`"asserts$(if ($IncludeNoAsserts) { ";noasserts" })`"";
+  foreach ($Build in $WindowsSDKBuilds) {
+    $Properties["WindowsRuntime$($Build.Architecture.ShortName.ToUpperInvariant())"] = [IO.Path]::Combine((Get-InstallDir $Build), "Runtimes", "$ProductVersion");
+    $Properties["WindowsExperimentalRuntime$($Build.Architecture.ShortName.ToUpperInvariant())"] = [IO.Path]::Combine((Get-InstallDir $Build), "Runtimes", "$ProductVersion.experimental");
   }
 
   Build-WiXProject bundle\installer.wixproj -Platform $Platform -Bundle -Properties $Properties
@@ -3111,10 +3959,8 @@ function Build-Installer([Hashtable] $Platform) {
 function Copy-BuildArtifactsToStage([Hashtable] $Platform) {
   Copy-File "$BinaryCache\$($Platform.Triple)\installer\Release\$($Platform.Architecture.VSName)\*.cab" $Stage
   Copy-File "$BinaryCache\$($Platform.Triple)\installer\Release\$($Platform.Architecture.VSName)\*.msi" $Stage
-  foreach ($SDKPlatform in $WindowsSDKPlatforms) {
-    Copy-File "$BinaryCache\$($Platform.Triple)\installer\Release\$($SDKPlatform.Architecture.VSName)\sdk.windows.$($SDKPlatform.Architecture.VSName).cab" $Stage
-    Copy-File "$BinaryCache\$($Platform.Triple)\installer\Release\$($SDKPlatform.Architecture.VSName)\sdk.windows.$($SDKPlatform.Architecture.VSName).msi" $Stage
-    Copy-File "$BinaryCache\$($Platform.Triple)\installer\Release\$($SDKPlatform.Architecture.VSName)\rtl.$($SDKPlatform.Architecture.VSName).msm" $Stage
+  foreach ($Build in $WindowsSDKBuilds) {
+    Copy-File "$BinaryCache\$($Platform.Triple)\installer\Release\$($Build.Architecture.VSName)\*.msm" $Stage
   }
   Copy-File "$BinaryCache\$($Platform.Triple)\installer\Release\$($Platform.Architecture.VSName)\installer.exe" $Stage
   # Extract installer engine to ease code-signing on swift.org CI
@@ -3126,29 +3972,59 @@ function Copy-BuildArtifactsToStage([Hashtable] $Platform) {
   Invoke-Program "$($WiX.Path)\wix.exe" -- burn detach "$BinaryCache\$($Platform.Triple)\installer\Release\$($Platform.Architecture.VSName)\installer.exe" -engine "$Stage\installer-engine.exe" -intermediateFolder "$BinaryCache\$($Platform.Triple)\installer\$($Platform.Architecture.VSName)\"
 }
 
+function Build-NoAssertsToolchain() {
+  if ($ToBatch) {
+    Write-Output ""
+    Write-Output "Building NoAsserts Toolchain ..."
+  } else {
+    Write-Host -ForegroundColor Cyan "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Building NoAsserts Toolchain ..."
+  }
+  $Stopwatch = [Diagnostics.Stopwatch]::StartNew()
+
+  Invoke-BuildStep Build-Compilers $HostPlatform -Variant "NoAsserts"
+
+  # Only compilers have NoAsserts enabled. Copy the rest of the Toolcahin binaries from the Asserts output
+  # Use robocopy for efficient copying
+  #   /E : Copies subdirectories, including empty ones.
+  #   /XC: Excludes existing files with the same timestamp but different file sizes.
+  #   /XN: Excludes existing files that are newer than the copy in the source directory.
+  #   /XO: Excludes existing files that are older than the copy in the source directory.
+  #   /NFL: Do not list coppied files in output
+  #   /NDL: Do not list directories in output
+  #   /NJH: Do not write a job header
+  #   /NC: Do not write file classes
+  #   /NS: Do not write file sizes
+  #   /NP: Do not show progress indicator
+  &robocopy $HostPlatform.ToolchainInstallRoot $HostPlatform.NoAssertsToolchainInstallRoot /E /XC /XN /XO /NS /NC /NFL /NDL /NJH
+
+  if (-not $ToBatch) {
+    Write-Host -ForegroundColor Cyan "[$([DateTime]::Now.ToString("yyyy-MM-dd HH:mm:ss"))] Building Instalting NoAsserts Toolchain in $($Stopwatch.Elapsed)"
+    Write-Host ""
+  }
+}
+
 #-------------------------------------------------------------------
 try {
 
 Get-Dependencies
 
 if ($Clean) {
+  Remove-Item -Force -Recurse -Path "$BinaryCache\$($BuildPlatform.Triple)\" -ErrorAction Ignore
   Remove-Item -Force -Recurse -Path "$BinaryCache\$($HostPlatform.Triple)\" -ErrorAction Ignore
-
-  # In case of a previous test run, clear out the swiftmodules as they are not a stable format.
-  Remove-Item -Force -Recurse -Path "$($HostPlatform.ToolchainInstallRoot)\usr\lib\swift\windows\*.swiftmodule" -ErrorAction Ignore
-  foreach ($Platform in $WindowsSDKPlatforms) {
-    Remove-Item -Force -Recurse -Path "$BinaryCache\$($Platform.Triple)\" -ErrorAction Ignore
+  foreach ($Build in $WindowsSDKBuilds) {
+    Remove-Item -Force -Recurse -Path "$BinaryCache\$($Build.Triple)\" -ErrorAction Ignore
   }
-  foreach ($Platform in $AndroidSDKPlatforms) {
-    Remove-Item -Force -Recurse -Path "$BinaryCache\$($Platform.Triple)\" -ErrorAction Ignore
+  foreach ($Build in $AndroidSDKBuilds) {
+    Remove-Item -Force -Recurse -Path "$BinaryCache\$($Build.Triple)\" -ErrorAction Ignore
   }
-
-  Remove-Item -Force -Recurse ([IO.Path]::Combine((Get-InstallDir $HostPlatform), "Runtimes", $ProductVersion)) -ErrorAction Ignore
+  Remove-Item -Force -Recurse -Path "$BinaryCache\1" -ErrorAction Ignore
+  Remove-Item -Force -Recurse -Path "$BinaryCache\5" -ErrorAction Ignore
+  Remove-Item -Force -Recurse -Path (Get-InstallDir $HostPlatform) -ErrorAction Ignore
 }
 
 if (-not $SkipBuild) {
-  if ($EnableCaching -And (-Not (Test-SCCacheAtLeast -Major 0 -Minor 7 -Patch 4))) {
-    throw "Minimum required sccache version is 0.7.4"
+  if ($EnableCaching) {
+    Invoke-Program (Get-SCCache).Path --zero-stats
   }
 
   Remove-Item -Force -Recurse ([IO.Path]::Combine((Get-InstallDir $HostPlatform), "Platforms")) -ErrorAction Ignore
@@ -3157,7 +4033,7 @@ if (-not $SkipBuild) {
   Invoke-BuildStep Build-BuildTools $BuildPlatform
   if ($IsCrossCompiling) {
     Invoke-BuildStep Build-XML2 $BuildPlatform
-    Invoke-BuildStep Build-Compilers $BuildPlatform
+    Invoke-BuildStep Build-Compilers $BuildPlatform -Variant "Asserts"
   }
   if ($IncludeDS2) {
     Invoke-BuildStep Build-RegsGen2 $BuildPlatform
@@ -3165,71 +4041,200 @@ if (-not $SkipBuild) {
 
   Invoke-BuildStep Build-CMark $HostPlatform
   Invoke-BuildStep Build-XML2 $HostPlatform
-  Invoke-BuildStep Build-Compilers $HostPlatform
-
-  foreach ($Platform in $WindowsSDKPlatforms) {
-    Invoke-BuildStep Build-ZLib $Platform
-    Invoke-BuildStep Build-XML2 $Platform
-    Invoke-BuildStep Build-CURL $Platform
-    Invoke-BuildStep Build-LLVM $Platform
-
-    # Build platform: SDK, Redist and XCTest
-    Invoke-BuildStep Build-Runtime $Platform
-    Invoke-BuildStep Build-Dispatch $Platform
-    # FIXME(compnerd) ensure that the _build_ is the first arch and don't rebuild on each arch
-    if ($Platform -eq $BuildPlatform) {
-      Invoke-BuildStep Build-FoundationMacros $BuildPlatform
-      Invoke-BuildStep Build-TestingMacros $BuildPlatform
-    }
-    Invoke-BuildStep Build-Foundation $Platform
-    Invoke-BuildStep Build-Sanitizers $Platform
-    Invoke-BuildStep Build-XCTest $Platform
-    Invoke-BuildStep Build-Testing $Platform
-    Invoke-BuildStep Write-SDKSettingsPlist $Platform
+  Invoke-BuildStep Build-CDispatch $HostPlatform
+  Invoke-BuildStep Build-Compilers $HostPlatform -Variant "Asserts"
+  $KnownPlatforms.Values | Where-Object {
+    switch ($_.OS) {
+      Windows { $Windows }
+      Android { $Android }
+      default { $false }
+    }
+  } | ForEach-Object {
+    Invoke-BuildStep Build-CompilerRuntime $_
+  }
 
-    Invoke-BuildStep Build-ExperimentalRuntime $Platform -Static
-    Invoke-BuildStep Build-Foundation $Platform -Static
+  # Build Macros
+  Build-CMakeProject `
+    -Src $SourceCache\swift-foundation\Sources\FoundationMacros `
+    -Bin (Get-ProjectBinaryCache $BuildPlatform BootstrapFoundationMacros) `
+    -BuildTargets default `
+    -Platform $BuildPlatform `
+    -UsePinnedCompilers Swift `
+    -SwiftSDK (Get-PinnedToolchainSDK -OS $BuildPlatform.OS) `
+    -Defines @{
+      SwiftSyntax_DIR = (Get-ProjectCMakeModules $BuildPlatform Compilers);
+    }
+
+  Build-CMakeProject `
+    -Src $SourceCache\swift-testing\Sources\TestingMacros `
+    -Bin (Get-ProjectBinaryCache $BuildPlatform BootstrapTestingMacros) `
+    -BuildTargets default `
+    -Platform $BuildPlatform `
+    -UsePinnedCompilers Swift `
+    -SwiftSDK (Get-PinnedToolchainSDK -OS $BuildPlatform.OS) `
+    -Defines @{
+      SwiftSyntax_DIR = (Get-ProjectCMakeModules $BuildPlatform Compilers);
+    }
+
+  if ($Windows) {
+    foreach ($Build in $WindowsSDKBuilds) {
+      if ($IncludeDS2) {
+        Invoke-BuildStep Build-DS2 $Build
+      }
+
+      Invoke-BuildStep Build-ZLib $Build
+      Invoke-BuildStep Build-XML2 $Build
+      Invoke-BuildStep Build-CURL $Build
+    }
+
+    foreach ($SDK in $WindowsSDKVersions) {
+      switch ($SDK) {
+        Windows {
+          $SDKROOT = Get-SwiftSDK -OS Windows -Identifier Windows
+          foreach ($Build in $WindowsSDKBuilds) {
+            Invoke-BuildStep Build-SDK $Build
+
+            Get-ChildItem "${SDKROOT}\usr\lib\swift\windows" -Filter "*.lib" -File -ErrorAction Ignore | ForEach-Object {
+              Write-Host -BackgroundColor DarkRed -ForegroundColor White "$($_.FullName) is not nested in an architecture directory"
+              Move-Item $_.FullName "${SDKROOT}\usr\lib\swift\windows\$($Build.Architecture.LLVMName)\" | Out-Null
+            }
+
+            # FIXME(compnerd) how do we select which SDK is meant to be re-distributed?
+            Copy-Directory "${SDKROOT}\usr\bin" "$([IO.Path]::Combine((Get-InstallDir $Build), "Runtimes", $ProductVersion, "usr"))"
+          }
+
+          Install-SDK $WindowsSDKBuilds
+          Write-SDKSettings Windows
+        }
+
+        WindowsExperimental {
+          $SDKROOT = Get-SwiftSDK -OS Windows -Identifier WindowsExperimental
+          foreach ($Build in $WindowsSDKBuilds) {
+            Invoke-BuildStep Build-ExperimentalSDK $Build
+
+            Get-ChildItem "${SDKROOT}\usr\lib\swift\windows" -Filter "*.lib" -File -ErrorAction Ignore | ForEach-Object {
+              Write-Host -BackgroundColor DarkRed -ForegroundColor White "$($_.FullName) is not nested in an architecture directory"
+              Move-Item $_.FullName "${SDKROOT}\usr\lib\swift\windows\$($Build.Architecture.LLVMName)\" | Out-Null
+            }
+
+            Get-ChildItem "${SDKROOT}\usr\lib\swift_static\windows" -Filter "*.lib" -File -ErrorAction Ignore | ForEach-Object {
+              Write-Host -BackgroundColor DarkRed -ForegroundColor White "$($_.FullName) is not nested in an architecture directory"
+              Move-Item $_.FullName "${SDKROOT}\usr\lib\swift_static\windows\$($Build.Architecture.LLVMName)\" | Out-Null
+            }
+
+            # FIXME(compnerd) how do we select which SDK is meant to be re-distributed?
+            Copy-Directory "${SDKROOT}\usr\bin" "$([IO.Path]::Combine((Get-InstallDir $Build), "Runtimes", "$ProductVersion.experimental", "usr"))"
+          }
+
+          Install-SDK $WindowsSDKBuilds -Identifier WindowsExperimental
+          Write-SDKSettings Windows -Identifier WindowsExperimental
+        }
+      }
+    }
+
+    foreach ($Build in $WindowsSDKBuilds) {
+      Invoke-BuildStep Build-XCTest $Build
+      Invoke-BuildStep Build-Testing $Build
+    }
+
+    Write-PlatformInfoPlist Windows
 
-    Copy-File "$(Get-SwiftSDK Windows)\usr\lib\swift\windows\*.lib" "$(Get-SwiftSDK Windows)\usr\lib\swift\windows\$($Platform.Architecture.LLVMName)\"
-    if ($Platform -eq $HostPlatform) {
-      Copy-Directory "$(Get-SwiftSDK Windows)\usr\bin" "$([IO.Path]::Combine((Get-InstallDir $HostPlatform), "Runtimes", $ProductVersion))\usr"
+    Invoke-BuildStep Build-PackageManagerRuntime $HostPlatform
+
+    # Copy static dependencies
+    foreach ($Build in $WindowsSDKBuilds) {
+      if (-not $Build.LinkModes.Contains("static")) { continue }
+
+      $SDKROOT = Get-SwiftSDK -OS $Build.OS -Identifier "$($Build.OS)Experimental"
+      Copy-Item -Force `
+        -Path "${BinaryCache}\$($Build.Triple)\curl\lib\libcurl.lib" `
+        -Destination "${SDKROOT}\usr\lib\swift_static\$($Build.OS.ToString().ToLowerInvariant())\$($Build.Architecture.LLVMName)\libcurl.lib" | Out-Null
+      Copy-Item -Force `
+        -Path "${BinaryCache}\$($Build.Triple)\libxml2-2.11.5\libxml2s.lib" `
+        -Destination "${SDKROOT}\usr\lib\swift_static\$($Build.OS.ToString().ToLowerInvariant())\$($Build.Architecture.LLVMName)\libxml2s.lib" | Out-Null
+      Copy-Item -Force `
+        -Path "${BinaryCache}\$($Build.Triple)\zlib\zlibstatic.lib" `
+        -Destination "${SDKROOT}\usr\lib\swift_static\$($Build.OS.ToString().ToLowerInvariant())\$($Build.Architecture.LLVMName)\zlibstatic.lib" | Out-Null
     }
   }
-  Install-Platform $WindowsSDKPlatforms Windows
-  Invoke-BuildStep Write-PlatformInfoPlist $HostPlatform
 
   if ($Android) {
-    foreach ($Platform in $AndroidSDKPlatforms) {
+    foreach ($Build in $AndroidSDKBuilds) {
       if ($IncludeDS2) {
-        Invoke-BuildStep Build-DS2 $Platform
+        Invoke-BuildStep Build-DS2 $Build
       }
-      Invoke-BuildStep Build-ZLib $Platform
-      Invoke-BuildStep Build-XML2 $Platform
-      Invoke-BuildStep Build-CURL $Platform
-      Invoke-BuildStep Build-LLVM $Platform
-
-      # Build platform: SDK, Redist and XCTest
-      Invoke-BuildStep Build-Runtime $Platform
-      Invoke-BuildStep Build-Dispatch $Platform
-      Invoke-BuildStep Build-Foundation $Platform
-      Invoke-BuildStep Build-Sanitizers $Platform
-      Invoke-BuildStep Build-XCTest $Platform
-      Invoke-BuildStep Build-Testing $Platform
-
-      # Android swift-inspect only supports 64-bit platforms.
-      if ($Platform.Architecture.ABI -in @("arm64-v8a", "x86_64")) {
-        Invoke-BuildStep Build-Inspect $Platform
+
+      Invoke-BuildStep Build-ZLib $Build
+      Invoke-BuildStep Build-XML2 $Build
+      Invoke-BuildStep Build-CURL $Build
+    }
+
+    foreach ($SDK in $AndroidSDKVersions) {
+      switch ($SDK) {
+        Android {
+          $SDKROOT = Get-SwiftSDK -OS Android -Identifier Android
+          foreach ($Build in $AndroidSDKBuilds) {
+            Invoke-BuildStep Build-SDK $Build
+
+            Get-ChildItem "${SDKROOT}\usr\lib\swift\android" -File | Where-Object { $_.Name -match ".a$|.so$" } | ForEach-Object {
+              Write-Host -BackgroundColor DarkRed -ForegroundColor White "$($_.FullName) is not nested in an architecture directory"
+              Move-Item $_.FullName "${SDKROOT}\usr\lib\swift\android\$($Build.Architecture.LLVMName)\" | Out-Null
+            }
+          }
+
+          Install-SDK $AndroidSDKBuilds
+          Write-SDKSettings Android
+        }
+
+        AndroidExperimental {
+          $SDKROOT = Get-SwiftSDK Android -Identifier AndroidExperimental
+          foreach ($Build in $AndroidSDKBuilds) {
+            Invoke-BuildStep Build-ExperimentalSDK $Build
+
+            Get-ChildItem "${SDKROOT}\usr\lib\swift\android" -File | Where-Object { $_.Name -match ".a$|.so$" } | ForEach-Object {
+              Write-Host -BackgroundColor DarkRed -ForegroundColor White "$($_.FullName) is not nested in an architecture directory"
+              Move-Item $_.FullName "${SDKROOT}\usr\lib\swift\android\$($Build.Architecture.LLVMName)\" | Out-Null
+            }
+
+            Get-ChildItem "${SDKROOT}\usr\lib\swift_static\android" -File | Where-Object { $_.Name -match ".a$|.so$" } | ForEach-Object {
+              Write-Host -BackgroundColor DarkRed -ForegroundColor White "$($_.FullName) is not nested in an architecture directory"
+              Move-Item $_.FullName "${SDKROOT}\usr\lib\swift_static\android\$($Build.Architecture.LLVMName)\" | Out-Null
+            }
+          }
+
+          Install-SDK $AndroidSDKBuilds -Identifiers AndroidExperimental
+          Write-SDKSettings Android -Identifier AndroidExperimental
+        }
       }
-      Invoke-BuildStep Write-SDKSettingsPlist $Platform
+    }
+
+    foreach ($Build in $AndroidSDKBuilds) {
+      Invoke-BuildStep Build-XCTest $Build
+      Invoke-BuildStep Build-Testing $Build
+    }
+
+    Write-PlatformInfoPlist Android
 
-      Invoke-BuildStep Build-ExperimentalRuntime $Platform -Static
-      Invoke-BuildStep Build-Foundation $Platform -Static
+    # Android swift-inspect only supports 64-bit platforms.
+    $AndroidSDKBuilds | Where-Object { @("arm64-v8a", "x86_64") -contains $_.Architecture.ABI } | ForEach-Object {
+      Invoke-BuildStep Build-Inspect $_
+    }
 
-      Move-Item "$(Get-SwiftSDK Android)\usr\lib\swift\android\*.a" "$(Get-SwiftSDK Android)\usr\lib\swift\android\$($Platform.Architecture.LLVMName)\"
-      Move-Item "$(Get-SwiftSDK Android)\usr\lib\swift\android\*.so" "$(Get-SwiftSDK Android)\usr\lib\swift\android\$($Platform.Architecture.LLVMName)\"
+    # Copy static dependencies
+    foreach ($Build in $AndroidSDKBuilds) {
+      if (-not $Build.LinkModes.Contains("static")) { continue }
+
+      $SDKROOT = Get-SwiftSDK -OS $Build.OS -Identifier "$($Build.OS)Experimental"
+      Copy-Item -Force `
+        -Path "${BinaryCache}\$($Build.Triple)\curl\lib\libcurl.a" `
+        -Destination "${SDKROOT}\usr\lib\swift_static\$($Build.OS.ToString().ToLowerInvariant())\$($Build.Architecture.LLVMName)\libcurl.a" | Out-Null
+      Copy-Item -Force `
+        -Path "${BinaryCache}\$($Build.Triple)\libxml2-2.11.5\libxml2.a" `
+        -Destination "${SDKROOT}\usr\lib\swift_static\$($Build.OS.ToString().ToLowerInvariant())\$($Build.Architecture.LLVMName)\libxml2.a" | Out-Null
+      Copy-Item -Force `
+        -Path "${BinaryCache}\$($Build.Triple)\zlib\libz.a" `
+        -Destination "${SDKROOT}\usr\lib\swift_static\$($Build.OS.ToString().ToLowerInvariant())\$($Build.Architecture.LLVMName)\libz.a" | Out-Null
     }
-    Install-Platform $AndroidSDKPlatforms Android
-    Invoke-BuildStep Write-PlatformInfoPlist $Platform
   }
 
   # Build Macros for distribution
@@ -3241,11 +4246,12 @@ if (-not $SkipBuild) {
   Invoke-BuildStep Build-LLBuild $HostPlatform
   Invoke-BuildStep Build-ArgumentParser $HostPlatform
   Invoke-BuildStep Build-Driver $HostPlatform
+  Invoke-BuildStep Build-ASN1 $HostPlatform
   Invoke-BuildStep Build-Crypto $HostPlatform
   Invoke-BuildStep Build-Collections $HostPlatform
-  Invoke-BuildStep Build-ASN1 $HostPlatform
   Invoke-BuildStep Build-Certificates $HostPlatform
   Invoke-BuildStep Build-System $HostPlatform
+  Invoke-BuildStep Build-Subprocess $HostPlatform
   Invoke-BuildStep Build-Build $HostPlatform
   Invoke-BuildStep Build-PackageManager $HostPlatform
   Invoke-BuildStep Build-Markdown $HostPlatform
@@ -3262,10 +4268,18 @@ if (-not $SkipBuild) {
   Invoke-BuildStep Build-mimalloc $HostPlatform
 }
 
+if (-not $SkipBuild -and $IncludeNoAsserts) {
+  Build-NoAssertsToolchain
+}
+
 if (-not $SkipBuild -and -not $IsCrossCompiling) {
   Invoke-BuildStep Build-DocC $HostPlatform
 }
 
+if (-not $SkipBuild) {
+  Invoke-BuildStep Patch-mimalloc $HostPlatform
+}
+
 if (-not $SkipPackaging) {
   Invoke-BuildStep Build-Installer $HostPlatform
 }
@@ -3284,7 +4298,7 @@ if (-not $IsCrossCompiling) {
       "-TestLLVM" = $Test -contains "llvm";
       "-TestSwift" = $Test -contains "swift";
     }
-    Invoke-BuildStep Test-Compilers $HostPlatform $Tests
+    Invoke-BuildStep Test-Compilers $HostPlatform -Variant "Asserts" $Tests
   }
 
   # FIXME(jeffdav): Invoke-BuildStep needs a platform dictionary, even though the Test-
@@ -3299,10 +4313,34 @@ if (-not $IsCrossCompiling) {
   if ($Test -contains "sourcekit-lsp") { Invoke-BuildStep Test-SourceKitLSP $BuildPlatform}
 
   if ($Test -contains "swift") {
-    foreach ($Platform in $AndroidSDKPlatforms) {
+    foreach ($Build in $AndroidSDKBuilds) {
       try {
-        Invoke-BuildStep Test-Runtime $Platform
-      } catch {}
+        Invoke-BuildStep Test-Runtime $Build
+      } catch {
+      }
+    }
+  }
+}
+
+if ($IncludeSBoM) {
+  Invoke-IsolatingEnvVars {
+    $env:SYFT_FILE_METADATA_SELECTION = "all"
+    $env:SYFT_FILE_CONTENT_GLOBS = "**\*.h"
+    $env:SYFT_FILE_METADATA_DIGESTS = "sha256"
+    Invoke-Program (Get-Syft).Path -- `
+        --base-path $BinaryCache `
+        --source-name Swift `
+        --source-version $ProductVersion `
+        -o spdx-json=$ToolchainIdentifier-sbom.spdx.json `
+        -o syft-json=$ToolchainIdentifier-sbom.syft.json `
+        -o cyclonedx-xml=$ToolchainIdentifier-sbom.cyclone.xml `
+        -o syft-table `
+        dir:$(Get-InstallDir $HostPlatform)
+
+    if ($Stage) {
+      Copy-File $ToolchainIdentifier-sbom.spdx.json $Stage
+      Copy-File $ToolchainIdentifier-sbom.syft.json $Stage
+      Copy-File $ToolchainIdentifier-sbom.cyclone.xml $Stage
     }
   }
 }
diff --git a/utils/build_swift/build_swift/defaults.py b/utils/build_swift/build_swift/defaults.py
index 99b7b85d72aad..07d0fbc228b6f 100644
--- a/utils/build_swift/build_swift/defaults.py
+++ b/utils/build_swift/build_swift/defaults.py
@@ -47,8 +47,8 @@
 CMAKE_GENERATOR = 'Ninja'
 
 COMPILER_VENDOR = 'none'
-SWIFT_USER_VISIBLE_VERSION = Version('6.2')
-CLANG_USER_VISIBLE_VERSION = Version('17.0.0')
+SWIFT_USER_VISIBLE_VERSION = Version('6.3')
+CLANG_USER_VISIBLE_VERSION = Version('21.0.0')
 SWIFT_ANALYZE_CODE_COVERAGE = 'false'
 
 DARWIN_XCRUN_TOOLCHAIN = 'default'
@@ -122,6 +122,8 @@ def llvm_install_components():
     """Convenience function for getting the default llvm install components for
     platforms.
     """
+    # llvm build product will take care of replacing compiler-rt with
+    # builtins,runtimes if need be
     components = ['llvm-ar', 'llvm-cov', 'llvm-profdata', 'IndexStore', 'clang',
                   'clang-resource-headers', 'compiler-rt', 'clangd', 'LTO',
                   'lld']
diff --git a/utils/build_swift/build_swift/driver_arguments.py b/utils/build_swift/build_swift/driver_arguments.py
index b5607775e73d0..e0e9f7cd87356 100644
--- a/utils/build_swift/build_swift/driver_arguments.py
+++ b/utils/build_swift/build_swift/driver_arguments.py
@@ -94,6 +94,9 @@ def _apply_default_arguments(args):
     if args.foundation_build_variant is None:
         args.foundation_build_variant = args.build_variant
 
+    if args.foundation_tests_build_variant is None:
+        args.foundation_tests_build_variant = args.build_variant
+
     if args.libdispatch_build_variant is None:
         args.libdispatch_build_variant = args.build_variant
 
@@ -129,6 +132,9 @@ def _apply_default_arguments(args):
     if args.lldb_assertions is None:
         args.lldb_assertions = args.assertions
 
+    if args.swift_stdlib_strict_availability is None:
+        args.swift_stdlib_strict_availability = False
+
     # --ios-all etc are not supported by open-source Swift.
     if args.ios_all:
         raise ValueError('error: --ios-all is unavailable in open-source '
@@ -197,6 +203,9 @@ def _apply_default_arguments(args):
     if args.test_optimize_none_with_implicit_dynamic:
         args.test = True
 
+    if args.test_optimize_none_with_opaque_values:
+        args.test = True
+
     # If none of tests specified skip swift stdlib test on all platforms
     if not args.test and not args.validation_test and not args.long_test:
         args.test_linux = False
@@ -286,6 +295,9 @@ def _apply_default_arguments(args):
         args.test_xros_host = False
         args.test_android_host = False
 
+    if args.build_wasmstdlib:
+        args.test_wasmstdlib = True
+
 
 def create_argument_parser():
     """Return a configured argument parser."""
@@ -540,6 +552,27 @@ def create_argument_parser():
            metavar='MAJOR.MINOR',
            help='minimum deployment target version for xrOS')
 
+    option('--darwin-test-deployment-version-osx', store,
+           default=defaults.DARWIN_DEPLOYMENT_VERSION_OSX,
+           metavar='MAJOR.MINOR',
+           help='deployment target version to use when building macOS tests')
+    option('--darwin-test-deployment-version-ios', store,
+           default=defaults.DARWIN_DEPLOYMENT_VERSION_IOS,
+           metavar='MAJOR.MINOR',
+           help='deployment target version to use when building iOS tests')
+    option('--darwin-test-deployment-version-tvos', store,
+           default=defaults.DARWIN_DEPLOYMENT_VERSION_TVOS,
+           metavar='MAJOR.MINOR',
+           help='deployment target version to use when building tvOS tests')
+    option('--darwin-test-deployment-version-watchos', store,
+           default=defaults.DARWIN_DEPLOYMENT_VERSION_WATCHOS,
+           metavar='MAJOR.MINOR',
+           help='deployment target version to use when building watchOS tests')
+    option('--darwin-test-deployment-version-xros', store,
+           default=defaults.DARWIN_DEPLOYMENT_VERSION_XROS,
+           metavar='MAJOR.MINOR',
+           help='deployment target version to use when building visionOS tests')
+
     option('--extra-cmake-options', append,
            type=argparse.ShellSplitType(),
            help='Pass through extra options to CMake in the form of comma '
@@ -592,6 +625,12 @@ def create_argument_parser():
                 'will get little benefit from it (e.g. tools for '
                 'bootstrapping or debugging Swift)')
 
+    option('--extra-swift-cmake-options', append,
+           type=argparse.ShellSplitType(),
+           help='Pass additional CMake options to the Swift build. '
+                'Can be passed multiple times to add multiple options.',
+           default=[])
+
     option('--dsymutil-jobs', store_int,
            default=defaults.DSYMUTIL_JOBS,
            metavar='COUNT',
@@ -674,6 +713,12 @@ def create_argument_parser():
                 "for each cross-compiled toolchain's destdir, useful when building "
                 "multiple toolchains and can be disabled if only cross-compiling one.")
 
+    option('--cross-compile-build-swift-tools', toggle_true,
+           default=True,
+           help="Cross-compile the Swift compiler, other host tools from the "
+                "compiler repository, and various macros for each listed "
+                "--cross-compile-hosts platform.")
+
     option('--stdlib-deployment-targets', store,
            type=argparse.ShellSplitType(),
            default=None,
@@ -811,11 +856,20 @@ def create_argument_parser():
     option(['--build-minimal-stdlib'], toggle_true('build_minimalstdlib'),
            help='build the \'minimal\' freestanding stdlib variant into a '
                 'separate build directory ')
+
+    # Wasm options
+
     option(['--build-wasm-stdlib'], toggle_true('build_wasmstdlib'),
            help='build the stdlib for WebAssembly target into a'
                 'separate build directory ')
+    option('--test-wasm-stdlib', toggle_true('test_wasmstdlib'),
+           help='test stdlib for WebAssembly')
     option(['--wasmkit'], toggle_true('build_wasmkit'),
            help='build WasmKit')
+    option(['--install-wasmkit'], toggle_true('install_wasmkit'),
+           help='install SourceKitLSP')
+
+    # Swift Testing options
 
     option('--swift-testing', toggle_true('build_swift_testing'),
            help='build Swift Testing')
@@ -955,6 +1009,12 @@ def create_argument_parser():
            const='Debug',
            help='build the Debug variant of Foundation')
 
+    option('--foundation-tests-build-type', store('foundation_tests_build_variant'),
+           choices=['Debug', 'Release'],
+           default=None,
+           help='build the Foundation tests in a certain variant '
+                '(Debug builds much faster)')
+
     option('--debug-libdispatch', store('libdispatch_build_variant'),
            const='Debug',
            help='build the Debug variant of libdispatch')
@@ -1029,6 +1089,14 @@ def create_argument_parser():
            const=False,
            help='disable assertions in llbuild')
 
+    option('--swift-stdlib-strict-availability', store,
+           const=True,
+           help='enable strict availability checking in the Swift standard library (you want this OFF for CI or at-desk builds)')
+    option('--no-swift-stdlib-strict-availability',
+           store('swift_stdlib_strict_availability'),
+           const=False,
+           help='disable strict availability checking in the Swift standard library (you want this OFF for CI or at-desk builds)')
+
     # -------------------------------------------------------------------------
     in_group('Select the CMake generator')
 
@@ -1084,6 +1152,12 @@ def create_argument_parser():
            help='run the test suite in optimize none with implicit dynamic'
                 'mode too (implies --test)')
 
+    # NOTE: this mode is meant to aid the bring-up of opaque values
+    # and once its enabled by default, we can remove this.
+    option('--test-optimize-none-with-opaque-values', toggle_true,
+           help='run the executable tests again, compiling them with '
+                '-enable-sil-opaque-values (implies --test)')
+
     option('--long-test', toggle_true,
            help='run the long test suite')
 
@@ -1395,14 +1469,27 @@ def create_argument_parser():
                 'Can be called multiple times '
                 'to add multiple such options.')
 
-    option('--no-llvm-include-tests', toggle_false('llvm_include_tests'),
-           help='do not generate testing targets for LLVM')
+    with mutually_exclusive_group():
+        set_defaults(llvm_include_tests=True)
+
+        option('--no-llvm-include-tests', toggle_false('llvm_include_tests'),
+               help='do not generate testing targets for LLVM')
+
+        option('--llvm-include-tests', toggle_true('llvm_include_tests'),
+               help='generate testing targets for LLVM')
 
     option('--llvm-cmake-options', append,
            type=argparse.ShellSplitType(),
            help='CMake options used for llvm in the form of comma '
                 'separated options "-DCMAKE_VAR1=YES,-DCMAKE_VAR2=/tmp". Can '
                 'be called multiple times to add multiple such options.')
+    option('--extra-llvm-cmake-options', append,
+           type=argparse.ShellSplitType(),
+           help='Pass additional CMake options to the LLVM build. '
+                'Can be passed multiple times to add multiple options. '
+                'These are the last arguments passed to CMake and can override '
+                'existing options.',
+           default=[])
 
     # -------------------------------------------------------------------------
     in_group('Build settings for Android')
diff --git a/utils/build_swift/build_swift/migration.py b/utils/build_swift/build_swift/migration.py
index dc6e0823647b9..c2549d06cb77f 100644
--- a/utils/build_swift/build_swift/migration.py
+++ b/utils/build_swift/build_swift/migration.py
@@ -12,6 +12,7 @@
 """
 
 
+from argparse import ArgumentParser
 import itertools
 import subprocess
 
@@ -97,7 +98,7 @@ def _process_disambiguation_arguments(args, unknown_args):
     return args, unknown_args
 
 
-def parse_args(parser, args, namespace=None):
+def parse_args(parser: ArgumentParser, args, namespace=None):
     """Parses a given argument list with the given argparse.ArgumentParser.
 
     Return a processed arguments object. Any unknown arguments are stored in
diff --git a/utils/build_swift/resources/SwiftPM-Unified-Build.xcworkspace/contents.xcworkspacedata b/utils/build_swift/resources/SwiftPM-Unified-Build.xcworkspace/contents.xcworkspacedata
index 98690cb842e09..cc6e4e14e4915 100644
--- a/utils/build_swift/resources/SwiftPM-Unified-Build.xcworkspace/contents.xcworkspacedata
+++ b/utils/build_swift/resources/SwiftPM-Unified-Build.xcworkspace/contents.xcworkspacedata
@@ -6,10 +6,13 @@
    <FileRef location = "group:../../../../sourcekit-lsp"></FileRef>
    <FileRef location = "group:../../../../swift-argument-parser"></FileRef>
    <FileRef location = "group:../../../../swift-collections"></FileRef>
+   <FileRef location = "group:../../../../swift-corelibs-foundation"></FileRef>
    <FileRef location = "group:../../../../swift-crypto"></FileRef>
    <FileRef location = "group:../../../../swift-docc"></FileRef>
    <FileRef location = "group:../../../../swift-driver"></FileRef>
    <FileRef location = "group:../../../../swift-format"></FileRef>
+   <FileRef location = "group:../../../../swift-foundation"></FileRef>
+   <FileRef location = "group:../../../../swift-foundation-icu"></FileRef>
    <FileRef location = "group:../../../../swift-stress-tester/SourceKitStressTester"></FileRef>
    <FileRef location = "group:../../../../swift-syntax"></FileRef>
    <FileRef location = "group:../../../../swift-syntax/CodeGeneration"></FileRef>
@@ -18,5 +21,4 @@
    <FileRef location = "group:../../../../swift-system"></FileRef>
    <FileRef location = "group:../../../../swift-tools-support-core"></FileRef>
    <FileRef location = "group:../../../../swiftpm"></FileRef>
-   <FileRef location = "group:../../../../yams"></FileRef>
 </Workspace>
diff --git a/utils/build_swift/tests/build_swift/test_driver_arguments.py b/utils/build_swift/tests/build_swift/test_driver_arguments.py
index 70d3a521fd0d8..5103be88b949b 100644
--- a/utils/build_swift/tests/build_swift/test_driver_arguments.py
+++ b/utils/build_swift/tests/build_swift/test_driver_arguments.py
@@ -515,6 +515,10 @@ def test_option_watchos_all(self):
         with self.assertRaises(ValueError):
             self.parse_default_args(['--watchos-all'])
 
+    def test_swift_stdlib_strict_availability(self):
+        self.parse_default_args('--swift-stdlib-strict-availability')
+        self.parse_default_args('--no-swift-stdlib-strict-availability')
+
     # -------------------------------------------------------------------------
     # Implied defaults tests
 
@@ -542,6 +546,7 @@ def test_implied_defaults_build_variant(self):
 
         self.assertEqual(namespace.cmark_build_variant, 'Debug')
         self.assertEqual(namespace.foundation_build_variant, 'Debug')
+        self.assertEqual(namespace.foundation_tests_build_variant, 'Debug')
         self.assertEqual(namespace.libdispatch_build_variant, 'Debug')
         self.assertEqual(namespace.lldb_build_variant, 'Debug')
         self.assertEqual(namespace.llvm_build_variant, 'Debug')
@@ -600,6 +605,11 @@ def test_implied_defaults_test_optimize_none_with_implicit_dynamic(self):
             ['--test-optimize-none-with-implicit-dynamic'])
         self.assertTrue(namespace.test)
 
+    def test_implied_defaults_test_optimize_none_with_opaque_values(self):
+        namespace = self.parse_default_args(
+            ['--test-optimize-none-with-opaque-values'])
+        self.assertTrue(namespace.test)
+
     def test_implied_defaults_skip_all_tests(self):
         namespace = self.parse_default_args([
             '--test', '0',
diff --git a/utils/build_swift/tests/build_swift/test_presets.py b/utils/build_swift/tests/build_swift/test_presets.py
index 495d8aa99812f..f2041d9c19fa4 100644
--- a/utils/build_swift/tests/build_swift/test_presets.py
+++ b/utils/build_swift/tests/build_swift/test_presets.py
@@ -44,6 +44,7 @@
     'ndk_path': '/path/to/ndk',
     'arm_dir': '/path/to/arm',
     'toolchain_path': '/tmp/toolchain',
+    'build_subdir': 'test_build_subdir',
 }
 
 SAMPLE_PRESET = """
diff --git a/utils/build_swift/tests/expected_options.py b/utils/build_swift/tests/expected_options.py
index d81c82b729d3d..60db08eef2fc7 100644
--- a/utils/build_swift/tests/expected_options.py
+++ b/utils/build_swift/tests/expected_options.py
@@ -119,6 +119,7 @@
     'install_swift_testing_macros': False,
     'install_swift_driver': False,
     'install_swiftdocc': False,
+    'install_wasmkit': False,
     'swiftsyntax_verify_generated_files': False,
     'swiftsyntax_enable_rawsyntax_validation': False,
     'swiftsyntax_enable_test_fuzzing': False,
@@ -155,6 +156,7 @@
     'compiler_vendor': defaults.COMPILER_VENDOR,
     'coverage_db': None,
     'cross_compile_append_host_target_to_destdir': True,
+    'cross_compile_build_swift_tools': True,
     'cross_compile_deps_path': None,
     'cross_compile_hosts': [],
     'infer_cross_compile_hosts_on_darwin': False,
@@ -168,6 +170,16 @@
         defaults.DARWIN_DEPLOYMENT_VERSION_WATCHOS,
     'darwin_deployment_version_xros':
         defaults.DARWIN_DEPLOYMENT_VERSION_XROS,
+    'darwin_test_deployment_version_osx':
+        defaults.DARWIN_DEPLOYMENT_VERSION_OSX,
+    'darwin_test_deployment_version_ios':
+        defaults.DARWIN_DEPLOYMENT_VERSION_IOS,
+    'darwin_test_deployment_version_tvos':
+        defaults.DARWIN_DEPLOYMENT_VERSION_TVOS,
+    'darwin_test_deployment_version_watchos':
+        defaults.DARWIN_DEPLOYMENT_VERSION_WATCHOS,
+    'darwin_test_deployment_version_xros':
+        defaults.DARWIN_DEPLOYMENT_VERSION_XROS,
     'darwin_symroot_path_filters': [],
     'darwin_xcrun_toolchain': None,
     'distcc': False,
@@ -197,10 +209,13 @@
     'enable_ubsan': False,
     'export_compile_commands': False,
     'extra_cmake_options': [],
+    'extra_llvm_cmake_options': [],
     'extra_swift_args': [],
+    'extra_swift_cmake_options': [],
     'swift_debuginfo_non_lto_args': None,
     'force_optimized_typechecker': False,
     'foundation_build_variant': 'Debug',
+    'foundation_tests_build_variant': 'Debug',
     'host_cc': None,
     'host_cxx': None,
     'host_libtool': None,
@@ -270,6 +285,7 @@
     'swift_profile_instr_use': None,
     'swift_runtime_fixed_backtracer_path': None,
     'swift_stdlib_assertions': True,
+    'swift_stdlib_strict_availability': False,
     'swift_stdlib_build_variant': 'Debug',
     'swift_tools_ld64_lto_codegen_only_for_supporting_targets': False,
     'swift_tools_max_parallel_lto_link_jobs':
@@ -298,6 +314,7 @@
     'test_linux_static': False,
     'test_optimize_for_size': None,
     'test_optimize_none_with_implicit_dynamic': None,
+    'test_optimize_none_with_opaque_values': False,
     'test_optimized': None,
     'test_osx': False,
     'test_paths': [],
@@ -323,7 +340,7 @@
     'test_swiftformat': False,
     'test_swiftdocc': False,
     'test_toolchainbenchmarks': False,
-    'test_wasmstdlib': True,
+    'test_wasmstdlib': False,
     'tvos': False,
     'tvos_all': False,
     'validation_test': None,
@@ -529,6 +546,8 @@ class BuildScriptImplOption(_BaseOption):
     SetOption('-s', dest='test_optimize_for_size', value=True),
     SetOption('-y',
               dest='test_optimize_none_with_implicit_dynamic', value=True),
+    SetOption('--test-optimize-none-with-opaque-values',
+              dest='test_optimize_none_with_opaque_values', value=True),
     SetOption('-t', dest='test', value=True),
     SetOption('-a', dest='assertions', value=True),
 
@@ -549,7 +568,12 @@ class BuildScriptImplOption(_BaseOption):
     SetOption('--skip-test-early-swift-driver',
               dest='test_early_swift_driver', value=False),
 
-    SetFalseOption('--no-llvm-include-tests', dest='llvm_include_tests'),
+    SetOption('--swift-stdlib-strict-availability', value=True),
+    SetOption('--no-swift-stdlib-strict-availability',
+              dest='swift_stdlib_strict_availability', value=False),
+
+    DisableOption('--no-llvm-include-tests', dest='llvm_include_tests'),
+    EnableOption('--llvm-include-tests', dest='llvm_include_tests'),
 
     SetTrueOption('--install-back-deploy-concurrency',
                   dest='install_backdeployconcurrency'),
@@ -581,6 +605,7 @@ class BuildScriptImplOption(_BaseOption):
     SetTrueOption('--swiftdocc', dest='build_swiftdocc'),
     SetTrueOption('--build-minimal-stdlib', dest='build_minimalstdlib'),
     SetTrueOption('--build-wasm-stdlib', dest='build_wasmstdlib'),
+    SetTrueOption('--test-wasm-stdlib', dest='test_wasmstdlib'),
     SetTrueOption('--wasmkit', dest='build_wasmkit'),
     SetTrueOption('--build-stdlib-docs'),
     SetTrueOption('--preview-stdlib-docs'),
@@ -617,6 +642,7 @@ class BuildScriptImplOption(_BaseOption):
     EnableOption('--build-swift-clang-overlays'),
     EnableOption('--build-swift-remote-mirror'),
     EnableOption('--cross-compile-append-host-target-to-destdir'),
+    EnableOption('--cross-compile-build-swift-tools'),
     EnableOption('--color-in-tests'),
     EnableOption('--distcc'),
     EnableOption('--sccache'),
@@ -675,6 +701,7 @@ class BuildScriptImplOption(_BaseOption):
     EnableOption('--install-swiftformat', dest='install_swiftformat'),
     EnableOption('--install-skstresstester', dest='install_skstresstester'),
     EnableOption('--install-swiftdocc', dest='install_swiftdocc'),
+    EnableOption('--install-wasmkit', dest='install_wasmkit'),
     EnableOption('--toolchain-benchmarks', dest='build_toolchainbenchmarks'),
     EnableOption('--swift-inspect', dest='build_swift_inspect'),
     EnableOption('--tsan-libdispatch-test'),
@@ -685,6 +712,7 @@ class BuildScriptImplOption(_BaseOption):
     EnableOption('--test'),
     EnableOption('--test-optimize-for-size'),
     EnableOption('--test-optimize-none-with-implicit-dynamic'),
+    EnableOption('--test-optimize-none-with-opaque-values'),
     EnableOption('--test-optimized'),
     EnableOption('--tvos'),
     EnableOption('--validation-test'),
@@ -782,6 +810,8 @@ class BuildScriptImplOption(_BaseOption):
                   choices=['false', 'not-merged', 'merged']),
     ChoicesOption('--android-arch',
                   choices=['armv7', 'aarch64', 'x86_64']),
+    ChoicesOption('--foundation-tests-build-type',
+                  dest='foundation_tests_build_variant', choices=['Debug', 'Release']),
 
     StrOption('--android-api-level'),
     StrOption('--build-args'),
@@ -791,6 +821,11 @@ class BuildScriptImplOption(_BaseOption):
     StrOption('--darwin-deployment-version-tvos'),
     StrOption('--darwin-deployment-version-watchos'),
     StrOption('--darwin-deployment-version-xros'),
+    StrOption('--darwin-test-deployment-version-osx'),
+    StrOption('--darwin-test-deployment-version-ios'),
+    StrOption('--darwin-test-deployment-version-tvos'),
+    StrOption('--darwin-test-deployment-version-watchos'),
+    StrOption('--darwin-test-deployment-version-xros'),
     DisableOption('--skip-test-xros-host', dest='test_xros_host'),
     DisableOption('--skip-test-xros', dest='test_xros'),
     DisableOption('--skip-test-xros-simulator', dest='test_xros_simulator'),
@@ -802,6 +837,7 @@ class BuildScriptImplOption(_BaseOption):
     StrOption('--swift-darwin-module-archs'),
     StrOption('--swift-darwin-supported-archs'),
     SetTrueOption('--swift-freestanding-is-darwin'),
+    AppendOption('--extra-swift-cmake-options'),
 
     StrOption('--linux-archs'),
     StrOption('--linux-static-archs'),
@@ -852,6 +888,7 @@ class BuildScriptImplOption(_BaseOption):
     AppendOption('--llvm-ninja-targets'),
     AppendOption('--llvm-ninja-targets-for-cross-compile-hosts'),
     AppendOption('--llvm-cmake-options'),
+    AppendOption('--extra-llvm-cmake-options'),
     AppendOption('--darwin-symroot-path-filters'),
 
     UnsupportedOption('--build-jobs'),
diff --git a/utils/dev-scripts/split-cmdline b/utils/dev-scripts/split-cmdline
index e2dbc23483788..a96b0bb677bb5 100755
--- a/utils/dev-scripts/split-cmdline
+++ b/utils/dev-scripts/split-cmdline
@@ -48,302 +48,339 @@ def main():
         is_arg_param = False
         # Handle escaped spaces
         args = shlex.split(line)
+        cmd_name = args[0]
         for arg in args:
-            if arg == "":
-                continue
-            if not first:
-                # Print option arguments in the same line
-                print(" " if is_arg_param else " \\\n  ", end="")
-            first = False
+            first, is_arg_param = print_arg(arg, first, is_arg_param, cmd_name)
 
-            # Expand @ option files
-            m = re.match(r"^@(\S+\.txt)$", arg)
-            if m:
-                cmd_file = m.group(1)
-                if os.path.isfile(cmd_file):
-                    with open(cmd_file) as f:
-                        for ln in f.readlines():
-                            for name in ln.rstrip().split(";"):
-                                if name != "":
-                                    print(name + " \\")
-                first = True
-                continue
+        # Print 2 new lines after each command line
+        print("\n")
 
-            if " " in arg or ";" in arg:
-                print('"' + arg + '"', end="")
-            else:
-                print(arg, end="")
 
-            # A hard-coded list of options which expect a parameter
-            is_arg_param = arg in [
-                # This list is generated by scraping --help menus from running:
-                #
-                #   $ ( \
-                #     swift --help;                 \
-                #     swift build --help;           \
-                #     swift run --help;             \
-                #     swift repl --help;            \
-                #     swift test --help;            \
-                #     swift package --help;         \
-                #     swiftc --help;                \
-                #     xcrun swift-frontend --help;  \
-                #     clang --help;                 \
-                #   ) | rg -o -r '$3 $2' -- ' ((-[\w-]+),)? (-[\w-]+) <' \
-                #     | sed 's/ *$//' | tr ' ' '\n' \
-                #     | sort | uniq \
-                #     | grep -v -e '-c$' \
-                #     | sed -E 's/(.*)/"\1",/'
-                "--analyzer-output",
-                "--build-system",
-                "--cache-path",
-                "--config-path",
-                "--configuration",
-                "--default-registry-url",
-                "--experimental-traits",
-                "--explicit-target-dependency-import-check",
-                "--filter",
-                "--jobs",
-                "--manifest-cache",
-                "--netrc-file",
-                "--num-workers",
-                "--package-path",
-                "--pkg-config-path",
-                "--product",
-                "--resolver-fingerprint-checking",
-                "--resolver-signing-entity-checking",
-                "--sanitize",
-                "--scratch-path",
-                "--sdk",
-                "--security-path",
-                "--skip",
-                "--specifier",
-                "--swift-sdk",
-                "--swift-sdks-path",
-                "--target",
-                "--toolchain",
-                "--triple",
-                "--xunit-output",
-                "-B",
-                "-D",
-                "-F",
-                "-Fsystem",
-                "-G",
-                "-I",
-                "-L",
-                "-MF",
-                "-MJ",
-                "-MQ",
-                "-MT",
-                "-T",
-                "-U",
-                "-Xanalyzer",
-                "-Xarch_device",
-                "-Xarch_host",
-                "-Xassembler",
-                "-Xcc",
-                "-Xclang",
-                "-Xcuda-fatbinary",
-                "-Xcuda-ptxas",
-                "-Xcxx",
-                "-Xlinker",
-                "-Xopenmp-target",
-                "-Xpreprocessor",
-                "-Xswiftc",
-                "-access-notes-path",
-                "-allowable-client",
-                "-api-diff-data-dir",
-                "-api-diff-data-file",
-                "-arcmt-migrate-report-output",
-                "-assert-config",
-                "-autolink-library",
-                "-b",
-                "-backup-module-interface-path",
-                "-blocklist-file",
-                "-build-id",
-                "-cache-replay-prefix-map",
-                "-cas-path",
-                "-cas-plugin-option",
-                "-cas-plugin-path",
-                "-cc1-args",
-                "-clang-build-session-file",
-                "-clang-scanner-module-cache-path",
-                "-clang-target",
-                "-compare-to-baseline-path",
-                "-const-gather-protocols-file",
-                "-coverage-prefix-map",
-                "-cxx-isystem",
-                "-darwin-target-variant",
-                "-darwin-target-variant-triple",
-                "-debug-info-format",
-                "-debug-prefix-map",
-                "-define-availability",
-                "-dependency-dot",
-                "-dependency-file",
-                "-dependency-scan-cache-path",
-                "-diagnostic-documentation-path",
-                "-diagnostic-style",
-                "-digester-breakage-allowlist-path",
-                "-digester-mode",
-                "-dsym-dir",
-                "-dump-api-path",
-                "-dump-migration-states-dir",
-                "-dump-scope-maps",
-                "-dumpdir",
-                "-e",
-                "-embed-tbd-for-module",
-                "-emit-abi-descriptor-path",
-                "-emit-api-descriptor-path",
-                "-emit-clang-header-path",
-                "-emit-const-values-path",
-                "-emit-dependencies-path",
-                "-emit-digester-baseline-path",
-                "-emit-fixits-path",
-                "-emit-loaded-module-trace-path",
-                "-emit-migrated-file-path",
-                "-emit-module-dependencies-path",
-                "-emit-module-doc-path",
-                "-emit-module-interface-path",
-                "-emit-module-path",
-                "-emit-module-semantic-info-path",
-                "-emit-module-serialize-diagnostics-path",
-                "-emit-module-source-info-path",
-                "-emit-module-summary-path",
-                "-emit-objc-header-path",
-                "-emit-reference-dependencies-path",
-                "-emit-remap-file-path",
-                "-emit-tbd-path",
-                "-enable-experimental-feature",
-                "-enable-upcoming-feature",
-                "-explain-module-dependency",
-                "-explain-module-dependency-detailed",
-                "-explicit-swift-module-map-file",
-                "-export-as",
-                "-external-plugin-path",
-                "-fdepscan-share-identifier",
-                "-file-compilation-dir",
-                "-file-prefix-map",
-                "-filelist",
-                "-fmodules-user-build-path",
-                "-framework",
-                "-group-info-path",
-                "-iapinotes-modules",
-                "-iapinotes-path",
-                "-idirafter",
-                "-iframework",
-                "-iframeworkwithsysroot",
-                "-imacros",
-                "-in-process-plugin-server-path",
-                "-include",
-                "-include-pch",
-                "-index-file-path",
-                "-index-store-path",
-                "-index-unit-output-path",
-                "-index-unit-output-path-filelist",
-                "-iprefix",
-                "-iquote",
-                "-isysroot",
-                "-isystem",
-                "-isystem-after",
-                "-ivfsoverlay",
-                "-ivfsstatcache",
-                "-iwithprefix",
-                "-iwithprefixbefore",
-                "-iwithsysroot",
-                "-j",
-                "-l",
-                "-libc",
-                "-load-plugin-executable",
-                "-load-plugin-library",
-                "-locale",
-                "-localization-path",
-                "-lto-library",
-                "-meabi",
-                "-mllvm",
-                "-mmlir",
-                "-module-abi-name",
-                "-module-alias",
-                "-module-cache-path",
-                "-module-can-import",
-                "-module-can-import-version",
-                "-module-dependency-dir",
-                "-module-link-name",
-                "-module-name",
-                "-mthread-model",
-                "-num-threads",
-                "-o",
-                "-output-file-map",
-                "-output-filelist",
-                "-package-name",
-                "-placeholder-dependency-module-map-file",
-                "-plugin-path",
-                "-prebuilt-module-cache-path",
-                "-primary-file",
-                "-primary-filelist",
-                "-project-name",
-                "-require-explicit-availability-target",
-                "-runtime-compatibility-version",
-                "-s",
-                "-save-optimization-record-passes",
-                "-save-optimization-record-path",
-                "-scanner-prefix-map",
-                "-scanner-prefix-map-sdk",
-                "-scanner-prefix-map-toolchain",
-                "-sdk",
-                "-serialize-breaking-changes-path",
-                "-serialize-diagnostics",
-                "-serialize-diagnostics-path",
-                "-serialized-path-obfuscate",
-                "-supplementary-output-file-map",
-                "-swift-isa-ptrauth-mode",
-                "-swift-module-cross-import",
-                "-swift-ptrauth-mode",
-                "-swift-version",
-                "-sysroot",
-                "-target",
-                "-target-cpu",
-                "-target-min-inlining-version",
-                "-target-variant",
-                "-tbd-compatibility-version",
-                "-tbd-current-version",
-                "-tbd-install_name",
-                "-tools-directory",
-                "-user-module-version",
-                "-verify-additional-file",
-                "-verify-additional-prefix",
-                "-verify-generic-signatures",
-                "-vfsoverlay",
-                "-visualc-tools-root",
-                "-visualc-tools-version",
-                "-windows-sdk-root",
-                "-windows-sdk-version",
-                "-working-directory",
-                "-x",
-                "-z",
-            ] + [
-                # This list contains options that do not appear in --help menus:
-                "-Xfrontend",
-                "-Xllvm",
-                "-add_ast_path",
-                "-arch",
-                "-emit-ir",
-                "-emit-sil",
-                "-fileno",
-                "-import-objc-header",
-                "-macosx_version_min",
-                "-resource-dir",
-                "-rpath",
-                "-syslibroot",
-                "-target-sdk-version",
-                "-target-sdk-name",
-            ]
-            # Heuristic: options ending in -path expect an argument
-            if arg.startswith("-") and arg.endswith("-path"):
-                is_arg_param = True
-            if arg == "-c" and args[0] == "swift":
-                is_arg_param = True
+def print_arg(arg, first, is_arg_param, cmd_name):
+    if arg == "":
+        return first, is_arg_param
+    if not first:
+        # Print option arguments in the same line
+        print(" " if is_arg_param else " \\\n  ", end="")
 
-        # Print 2 new lines after each command line
-        print("\n")
+    # Expand @ option files
+    m = re.match(r"^@(\S+(\.resp))$", arg)
+    if m:
+        cmd_file = m.group(1)
+        cmd_first = False
+        if os.path.isfile(cmd_file):
+            cmd_first = True
+            with open(cmd_file) as f:
+                for ln in f.readlines():
+                    cmd_args = shlex.split(ln)
+                    for cmd_arg in cmd_args:
+                        cmd_first, is_arg_param = print_arg(cmd_arg, cmd_first, is_arg_param, cmd_name)
+        else:
+            print(arg, end="")
+        return cmd_first, is_arg_param
+
+    m = re.match(r"^@(\S+(\.txt|FileList))$", arg)
+    if m:
+        cmd_file = m.group(1)
+        if os.path.isfile(cmd_file):
+            with open(cmd_file) as f:
+                for ln in f.readlines():
+                    for name in ln.rstrip().split(";"):
+                        print(name + " \\")
+        return True, is_arg_param
+
+    if " " in arg or ";" in arg:
+        print('"' + arg + '"', end="")
+    else:
+        print(arg, end="")
+
+    # A hard-coded list of options which expect a parameter
+    is_next_arg_param = arg in [
+        # This list is generated by scraping --help menus from running:
+        #
+        #   $ ( \
+        #     swift --help;                 \
+        #     swift build --help;           \
+        #     swift run --help;             \
+        #     swift repl --help;            \
+        #     swift test --help;            \
+        #     swift package --help;         \
+        #     swiftc --help;                \
+        #     xcrun swift-frontend --help;  \
+        #     xcrun swift-api-digester --help; \
+        #     clang --help;                 \
+        #   ) | rg -o -r '$3 $2' -- ' ((-[\w-]+),)? (-[\w-]+) <' \
+        #     | sed 's/ *$//' | tr ' ' '\n' \
+        #     | sort | uniq \
+        #     | grep -v -e '-c$' \
+        #     | sed -E 's/(.*)/"\1",/'
+        "--analyzer-output",
+        "--build-system",
+        "--cache-path",
+        "--config-path",
+        "--configuration",
+        "--default-registry-url",
+        "--experimental-traits",
+        "--explicit-target-dependency-import-check",
+        "--filter",
+        "--jobs",
+        "--manifest-cache",
+        "--netrc-file",
+        "--num-workers",
+        "--package-path",
+        "--pkg-config-path",
+        "--product",
+        "--resolver-fingerprint-checking",
+        "--resolver-signing-entity-checking",
+        "--sanitize",
+        "--scratch-path",
+        "--sdk",
+        "--security-path",
+        "--skip",
+        "--specifier",
+        "--swift-sdk",
+        "--swift-sdks-path",
+        "--target",
+        "--toolchain",
+        "--triple",
+        "--xunit-output",
+        "-B",
+        "-D",
+        "-F",
+        "-Fsystem",
+        "-G",
+        "-I",
+        "-Isystem",
+        "-L",
+        "-MF",
+        "-MJ",
+        "-MQ",
+        "-MT",
+        "-T",
+        "-U",
+        "-Xanalyzer",
+        "-Xarch_device",
+        "-Xarch_host",
+        "-Xassembler",
+        "-Xcc",
+        "-Xclang",
+        "-Xcuda-fatbinary",
+        "-Xcuda-ptxas",
+        "-Xcxx",
+        "-Xlinker",
+        "-Xopenmp-target",
+        "-Xpreprocessor",
+        "-Xswiftc",
+        "-access-notes-path",
+        "-allowable-client",
+        "-api-diff-data-dir",
+        "-api-diff-data-file",
+        "-arcmt-migrate-report-output",
+        "-assert-config",
+        "-autolink-library",
+        "-b",
+        "-backup-module-interface-path",
+        "-blocklist-file",
+        "-build-id",
+        "-cache-replay-prefix-map",
+        "-cas-path",
+        "-cas-plugin-option",
+        "-cas-plugin-path",
+        "-cc1-args",
+        "-clang-build-session-file",
+        "-clang-scanner-module-cache-path",
+        "-clang-target",
+        "-clang-target-variant",
+        "-compare-to-baseline-path",
+        "-const-gather-protocols-file",
+        "-coverage-prefix-map",
+        "-cxx-isystem",
+        "-darwin-target-variant",
+        "-darwin-target-variant-triple",
+        "-debug-info-format",
+        "-debug-prefix-map",
+        "-define-availability",
+        "-dependency-dot",
+        "-dependency-file",
+        "-dependency-scan-cache-path",
+        "-diagnostic-documentation-path",
+        "-diagnostic-style",
+        "-digester-breakage-allowlist-path",
+        "-digester-mode",
+        "-dsym-dir",
+        "-dump-api-path",
+        "-dump-migration-states-dir",
+        "-dump-scope-maps",
+        "-dumpdir",
+        "-e",
+        "-embed-tbd-for-module",
+        "-emit-abi-descriptor-path",
+        "-emit-api-descriptor-path",
+        "-emit-clang-header-path",
+        "-emit-const-values-path",
+        "-emit-dependencies-path",
+        "-emit-digester-baseline-path",
+        "-emit-fixits-path",
+        "-emit-loaded-module-trace-path",
+        "-emit-migrated-file-path",
+        "-emit-module-dependencies-path",
+        "-emit-module-doc-path",
+        "-emit-module-interface-path",
+        "-emit-module-path",
+        "-emit-module-semantic-info-path",
+        "-emit-module-serialize-diagnostics-path",
+        "-emit-module-source-info-path",
+        "-emit-module-summary-path",
+        "-emit-objc-header-path",
+        "-emit-reference-dependencies-path",
+        "-emit-remap-file-path",
+        "-emit-tbd-path",
+        "-enable-experimental-feature",
+        "-enable-upcoming-feature",
+        "-explain-module-dependency",
+        "-explain-module-dependency-detailed",
+        "-explicit-swift-module-map-file",
+        "-export-as",
+        "-external-plugin-path",
+        "-fdepscan-share-identifier",
+        "-file-compilation-dir",
+        "-file-prefix-map",
+        "-filelist",
+        "-fmodules-user-build-path",
+        "-framework",
+        "-group-info-path",
+        "-iapinotes-modules",
+        "-iapinotes-path",
+        "-idirafter",
+        "-iframework",
+        "-iframeworkwithsysroot",
+        "-imacros",
+        "-in-process-plugin-server-path",
+        "-include",
+        "-include-pch",
+        "-index-file-path",
+        "-index-store-path",
+        "-index-unit-output-path",
+        "-index-unit-output-path-filelist",
+        "-iprefix",
+        "-iquote",
+        "-isysroot",
+        "-isystem",
+        "-isystem-after",
+        "-ivfsoverlay",
+        "-ivfsstatcache",
+        "-iwithprefix",
+        "-iwithprefixbefore",
+        "-iwithsysroot",
+        "-j",
+        "-l",
+        "-libc",
+        "-load-plugin-executable",
+        "-load-plugin-library",
+        "-load-resolved-plugin",
+        "-locale",
+        "-localization-path",
+        "-lto-library",
+        "-meabi",
+        "-mllvm",
+        "-mmlir",
+        "-module",
+        "-module-abi-name",
+        "-module-alias",
+        "-module-cache-path",
+        "-module-can-import",
+        "-module-can-import-version",
+        "-module-dependency-dir",
+        "-module-link-name",
+        "-module-name",
+        "-mthread-model",
+        "-num-threads",
+        "-o",
+        "-output-file-map",
+        "-output-filelist",
+        "-package-name",
+        "-placeholder-dependency-module-map-file",
+        "-plugin-path",
+        "-prebuilt-module-cache-path",
+        "-primary-file",
+        "-primary-filelist",
+        "-project-name",
+        "-require-explicit-availability-target",
+        "-runtime-compatibility-version",
+        "-s",
+        "-save-optimization-record-passes",
+        "-save-optimization-record-path",
+        "-scanner-prefix-map",
+        "-scanner-prefix-map-sdk",
+        "-scanner-prefix-map-toolchain",
+        "-sdk",
+        "-serialize-breaking-changes-path",
+        "-serialize-diagnostics",
+        "-serialize-diagnostics-path",
+        "-serialized-path-obfuscate",
+        "-supplementary-output-file-map",
+        "-swift-isa-ptrauth-mode",
+        "-swift-module-cross-import",
+        "-swift-ptrauth-mode",
+        "-swift-version",
+        "-sysroot",
+        "-target",
+        "-target-cpu",
+        "-target-min-inlining-version",
+        "-target-variant",
+        "-tbd-compatibility-version",
+        "-tbd-current-version",
+        "-tbd-install_name",
+        "-tools-directory",
+        "-use-interface-for-module",
+        "-user-module-version",
+        "-verify-additional-file",
+        "-verify-additional-prefix",
+        "-verify-generic-signatures",
+        "-vfsoverlay",
+        "-visualc-tools-root",
+        "-visualc-tools-version",
+        "-windows-sdk-root",
+        "-windows-sdk-version",
+        "-working-directory",
+        "-x",
+        "-z",
+    ] + [
+        # This list contains options that do not appear in --help menus:
+        "-Xfrontend",
+        "-Xllvm",
+        "-add_ast_path",
+        "-arch",
+        "-emit-ir",
+        "-emit-sil",
+        "-ferror-limit",
+        "-fileno",
+        "-fmodule-feature",
+        "-import-objc-header",
+        "-internal-externc-isystem",
+        "-library-level",
+        "-macosx_version_min",
+        "-pic-level",
+        "-resource-dir",
+        "-rpath",
+        "-stack-protector",
+        "-stack-protector-buffer-size",
+        "-syslibroot",
+        "-target-abi",
+        "-target-feature",
+        "-target-linker-version",
+        "-target-sdk-name",
+        "-target-sdk-version",
+        "-target-variant-sdk-version",
+        "-triple",
+        "-typecheck-module-from-interface",
+    ]
+    # Heuristic: options ending in -path expect an argument
+    if arg != "-finclude-tree-preserve-pch-path" and arg.startswith("-") and arg.endswith("-path"):
+        is_next_arg_param = True
+    if arg == "-c" and (cmd_name == "swift" or os.path.basename(cmd_name) == "clang"):
+        is_next_arg_param = True
+    return False, is_next_arg_param
 
 
 if __name__ == "__main__":
diff --git a/utils/download-unpublished-toolchains.py b/utils/download-unpublished-toolchains.py
index 1b1dca5e7ae65..f588d313a910e 100755
--- a/utils/download-unpublished-toolchains.py
+++ b/utils/download-unpublished-toolchains.py
@@ -15,6 +15,7 @@
 
 import argparse
 import os
+import re
 import sys
 import tarfile
 import urllib.request
@@ -38,7 +39,7 @@ def get_latest_toolchain_url(build_url):
     lines = body.split('\n')
     toolchain = [x for x in lines if 'Toolchain:' in x]
     if len(toolchain) > 0:
-        toolchain_url = toolchain[0].removeprefix('Toolchain: ')
+        toolchain_url = re.sub(r'.+Toolchain: (.+)$', r'\1', toolchain[0])
     return toolchain_url
 
 
@@ -90,6 +91,12 @@ def parse_args():
         help="Untar the toolchain in the output directory",
     )
 
+    parser.add_argument(
+        "--dry-run",
+        default=False,
+        action='store_true',
+        help="Infer the toolchain URL but don't download it")
+
     return parser.parse_args()
 
 
@@ -105,13 +112,15 @@ def main():
     if not toolchain_url:
         print(f"Error: Unable to find toolchain for {args.platform}.")
         return -1
-    print(f"[Downloading] {toolchain_url}")
-    output_path = download_toolchain(toolchain_url, args.output_dir)
-    print(f"[Toolchain] {output_path}")
+    print(f"[Toolchain URL] {toolchain_url}")
+
+    if not args.dry_run:
+        output_path = download_toolchain(toolchain_url, args.output_dir)
+        print(f"[Toolchain] {output_path}")
 
-    if args.untar:
-        untar_toolchain(args.output_dir, output_path)
-        print(f"[Extracted] {args.output_dir}/usr")
+        if args.untar:
+            untar_toolchain(args.output_dir, output_path)
+            print(f"[Extracted] {args.output_dir}/usr")
 
 
 if __name__ == "__main__":
diff --git a/utils/embedded-test-support/libc.c b/utils/embedded-test-support/libc.c
index b502cfbc5585f..04dd19c25b8a4 100644
--- a/utils/embedded-test-support/libc.c
+++ b/utils/embedded-test-support/libc.c
@@ -81,7 +81,7 @@ int memcmp(const void *s1, const void *s2, size_t n) {
 
 __attribute__((used))
 void *memmove(void *dst, const void *src, size_t n) {
-  if ((uintptr_t)dst > (uintptr_t)src) {
+  if ((uintptr_t)dst < (uintptr_t)src) {
     for (int i = 0; i < n; i++) {
       ((char *)dst)[i] = ((char *)src)[i];
     }
diff --git a/utils/generate-doc-index.swift b/utils/generate-doc-index.swift
new file mode 100755
index 0000000000000..b9396bd803867
--- /dev/null
+++ b/utils/generate-doc-index.swift
@@ -0,0 +1,242 @@
+#!/usr/bin/env swift -enable-upcoming-feature BareSlashRegexLiterals
+
+import Foundation
+
+let usage = """
+./\(CommandLine.arguments[0]) <swift-source-directory> [output-directory]
+
+Generates index files for diagnostics notes, groups, and upcoming features.
+"""
+
+let docsDir = "userdocs/diagnostics"
+let topLevelFileName = "diagnostics.md"
+
+let notesDocFileName = "diagnostic-descriptions.md"
+let notesHeader = """
+# Diagnostic descriptions
+
+<!-- This file is auto-generated via `swift swift/utils/generate-doc-index.swift` -->
+
+Detailed explanations for various compiler diagnostics.
+
+
+## Overview
+
+Swift diagnostics are classified into errors and warnings. Warnings can only be silenced in an
+intentional manner, e.g., adding `_ =` for an unused function result.
+
+Some diagnostics have more detailed explanations available. These include a `[#Name]` inline and
+reference to this documentation at the end of the compiler output on the command line, or is
+presented specially within your IDE of choice. See below for the full list of these notes.
+
+
+## Topics
+
+
+"""
+
+let groupsDocFileName = "diagnostic-groups.md"
+let groupsHeader = """
+# Diagnostic groups
+
+<!-- This file is auto-generated via `swift swift/utils/generate-doc-index.swift` -->
+
+Diagnostic groups allow controlling the behavior of warnings in a more precise manner.
+
+
+## Overview
+
+Diagnostic groups collect some number of diagnostics together under a common group name. This allows
+for extra documentation to help explain relevant language concepts, as well as the ability to
+control the behavior of warnings in a more precise manner:
+- `-Werror <group>` - upgrades warnings in the specified group to errors
+- `-Wwarning <group>` - indicates that warnings in the specified group should remain warnings, even
+  if they were previously upgraded to errors
+
+As a concrete example, to upgrade deprecated declaration warnings to errors:
+```sh
+-Werror DeprecatedDeclaration
+```
+
+Or upgrade all warnings except deprecated declaration to errors:
+```sh
+-warnings-as-errors -Wwarning DeprecatedDeclaration
+```
+
+
+## Topics
+
+
+"""
+
+let featuresDocFileName = "upcoming-language-features.md"
+let featuresHeader = """
+# Upcoming language features
+
+<!-- This file is auto-generated via `swift swift/utils/generate-doc-index.swift` -->
+
+Upcoming language features enable new (but potentially source breaking) functionality that be
+enabled by default in an upcoming language mode.
+
+
+## Overview
+
+Upcoming language features allow the incremental adoption of language features that would otherwise
+only be available in a new language mode, without having to fully migrate to that mode. They can be
+enabled on the command line with `-enable-upcoming-feature <feature>`.
+
+Some upcoming features have an additional "migration" mode, where the compiler will emit warnings
+with fix-its to help migrate to that mode. This can be enabled with `-enable-upcoming-feature
+<feature>:migrate`.
+
+
+## Topics
+
+
+"""
+
+let groupsFileName = "include/swift/AST/DiagnosticGroups.def"
+let groupRegex = /GROUP\(([a-zA-Z]+), ".+"\)/
+
+let featuresFileName = "include/swift/Basic/Features.def"
+let featuresRegex = /UPCOMING_FEATURE\(([a-zA-Z]+), .+\)/
+
+let nameRegex = /# .+ \((?<name>[a-zA-Z]+)\)/
+
+var args = CommandLine.arguments.dropFirst()
+if args.count != 1 && args.count != 2 {
+  print(usage)
+  exit(2)
+}
+
+let swiftSourceDir = args.removeFirst()
+let outputDir: String
+if !args.isEmpty {
+  outputDir = args.removeFirst()
+} else {
+  outputDir = "\(swiftSourceDir)/\(docsDir)"
+}
+
+let generator = GenerateUserDocs(swiftSourceDir: swiftSourceDir, outputDir: outputDir)
+do {
+  try generator.generateIndex()
+} catch {
+  print("error: \(error)")
+  exit(1)
+}
+
+struct GenerateUserDocs {
+  let swiftSourceDir: String
+  let outputDir: String
+
+  func generateIndex() throws {
+    let notesHandle = try createIndex(name: notesDocFileName, header: notesHeader)
+    defer { try? notesHandle.close() }
+
+    let groupsHandle = try createIndex(name: groupsDocFileName, header: groupsHeader)
+    defer { try? groupsHandle.close() }
+
+    let featuresHandle = try createIndex(name: featuresDocFileName, header: featuresHeader)
+    defer { try? featuresHandle.close() }
+
+    let docs = try retrieveDocs().sorted { a, b in
+      return a.title < b.title
+    }
+
+    for doc in docs {
+      let handle: FileHandle
+      switch doc.kind {
+      case .note:
+        handle = notesHandle
+      case .group:
+        handle = groupsHandle
+      case .feature:
+        handle = featuresHandle
+      }
+
+      let ref = "- <doc:\(doc.name.dropLast(3))>\n"
+      try handle.write(contentsOf: ref.data(using: .utf8)!)
+    }
+  }
+
+  func createIndex(name: String, header: String) throws -> FileHandle {
+    let path = "\(outputDir)/\(name)"
+
+    if FileManager.default.fileExists(atPath: path) {
+      try FileManager.default.removeItem(atPath: path)
+    }
+    FileManager.default.createFile(atPath: path, contents: nil)
+
+    let handle = try FileHandle(forWritingTo: URL(filePath: path))
+    try handle.write(contentsOf: header.data(using: .utf8)!)
+    return handle
+  }
+
+  func matches(in fileName: String, with regex: Regex<(Substring, Substring)>) throws -> Set<String> {
+    let file = try String(contentsOfFile: "\(swiftSourceDir)/\(fileName)", encoding: .utf8)
+
+    var matches: Set<String> = []
+    for line in file.components(separatedBy: .newlines) {
+      if let match = try? regex.firstMatch(in: line) {
+        matches.insert(String(match.1))
+      }
+    }
+
+    return matches
+  }
+
+  func retrieveDocs() throws -> [UserDoc] {
+    let groups = try matches(in: groupsFileName, with: groupRegex)
+    let features = try matches(in: featuresFileName, with: featuresRegex)
+
+    var docs: [UserDoc] = []
+
+    let files = try FileManager.default.contentsOfDirectory(atPath: "\(swiftSourceDir)/\(docsDir)")
+    for name in files {
+      if !name.hasSuffix(".md")
+          || name.hasSuffix(topLevelFileName)
+          || name.hasSuffix(notesDocFileName)
+          || name.hasSuffix(groupsDocFileName)
+          || name.hasSuffix(featuresDocFileName) {
+        continue
+      }
+
+      let file = try String(contentsOfFile: "\(swiftSourceDir)/\(docsDir)/\(name)", encoding: .utf8)
+
+      if let match = try? nameRegex.prefixMatch(in: file) {
+        let groupName = String(match.name)
+
+        let kind: UserDoc.Kind
+        if features.contains(groupName) {
+          kind = .feature
+        } else if groups.contains(groupName) {
+          kind = .group
+        } else {
+          kind = .note
+        }
+
+        docs.append(UserDoc(name: name, title: String(match.0), kind: kind))
+      } else {
+        if let newlineIndex = file.firstIndex(of: "\n") {
+          docs.append(UserDoc(name: name, title: String(file[..<newlineIndex]), kind: .note))
+        } else {
+          docs.append(UserDoc(name: name, title: file, kind: .note))
+        }
+      }
+    }
+
+    return docs
+  }
+}
+
+struct UserDoc {
+  enum Kind {
+    case note
+    case group
+    case feature
+  }
+
+  let name: String
+  let title: String
+  let kind: Kind
+}
diff --git a/utils/git-clang-format-all.zsh b/utils/git-clang-format-all.zsh
new file mode 100755
index 0000000000000..7e62321d3e9d9
--- /dev/null
+++ b/utils/git-clang-format-all.zsh
@@ -0,0 +1,76 @@
+#!/usr/bin/env zsh
+#===--- git-clang-format-all.sh --------------------------------------------===#
+#
+#  This source file is part of the Swift.org open source project
+# 
+#  Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+#  Licensed under Apache License v2.0 with Runtime Library Exception
+# 
+#  See https://swift.org/LICENSE.txt for license information
+#  See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+#
+#===------------------------------------------------------------------------===#
+#
+# This is a script that uses git-clang-format, git commit --fixup, and git
+# rebase --autosquash to apply git-clang-format fixups automatically to all
+# commits up to the parent commit of the passed in hash. The intent is that one
+# can work on a branch, get it to the point one is ready to commit, run this
+# script so that all git commits on ones branch are formatted and the create a
+# PR.
+#
+#===------------------------------------------------------------------------===#
+
+set -e
+
+if [[ $# -ne 1 ]]; then
+    echo "Usage: $0 <git-hash>"
+    echo "Applies git-clang-format to each commit backwards from HEAD to the given git hash and squashes the fixes into those commits using git commit --fixup and git-rebase --autosquash"
+    exit 1
+fi
+
+TARGET_HASH="$1^"
+
+if ! git rev-parse --verify "$TARGET_HASH" >/dev/null 2>&1; then
+    echo "Error: '$TARGET_HASH' is not a valid git hash"
+    exit 1
+fi
+
+if ! command -v git-clang-format >/dev/null 2>&1; then
+    echo "Error: git-clang-format not found in PATH"
+    exit 1
+fi
+
+if ! git diff --quiet >/dev/null; then
+    echo "Have changes in tree. Must not have changes in tree to run this script"
+    exit 1
+fi
+
+if ! git diff --cached --quiet >/dev/null; then
+    echo "Have staged changes in tree. Must not have staged changes in tree to run this script"
+    exit 1
+fi
+
+echo "Formatting up to $(git log --oneline -1 ${TARGET_HASH})"
+
+COMMITS=($(git rev-list "$TARGET_HASH"..HEAD))
+
+if [[ ${#COMMITS[@]} -eq 0 ]]; then
+    echo "No commits found between $TARGET_HASH and HEAD"
+    exit 0
+fi
+
+echo "Found ${#COMMITS[@]} commits to format"
+
+for commit in "${COMMITS[@]}"; do
+    echo "Processing commit: $commit ($(git log --oneline -1 $commit))"
+    
+    if ! git-clang-format "${commit}^" >/dev/null ; then
+        echo "    Formatting required"
+        git commit --quiet -a --fixup "${commit}"
+        git -c sequence.editor=: rebase -i --autosquash --quiet "${commit}^"
+    else
+        echo "    No formatting changes needed"
+    fi
+done
+
+echo "All commits formatted successfully"
diff --git a/utils/gyb_sourcekit_support/UIDs.py b/utils/gyb_sourcekit_support/UIDs.py
index eed16a62ab4d8..d0fbecd686e3e 100644
--- a/utils/gyb_sourcekit_support/UIDs.py
+++ b/utils/gyb_sourcekit_support/UIDs.py
@@ -61,6 +61,10 @@ def __init__(self, internal_name, external_name):
     KEY('FullyAnnotatedDecl', 'key.fully_annotated_decl'),
     KEY('FullyAnnotatedGenericSignature',
         'key.fully_annotated_generic_signature'),
+    KEY('Signatures', 'key.signatures'),
+    KEY('ActiveSignature', 'key.active_signature'),
+    KEY('Parameters', 'key.parameters'),
+    KEY('ActiveParameter', 'key.active_parameter'),
     KEY('DocBrief', 'key.doc.brief'),
     KEY('Context', 'key.context'),
     KEY('TypeRelation', 'key.typerelation'),
@@ -219,6 +223,7 @@ def __init__(self, internal_name, external_name):
     KEY('IndexStorePath', 'key.index_store_path'),
     KEY('IndexUnitOutputPath', 'key.index_unit_output_path'),
     KEY('IncludeLocals', 'key.include_locals'),
+    KEY('Compress', 'key.compress'),
     KEY('IgnoreClangModules', 'key.ignore_clang_modules'),
     KEY('IncludeSystemModules', 'key.include_system_modules'),
     KEY('IgnoreStdlib', 'key.ignore_stdlib'),
@@ -253,6 +258,7 @@ def __init__(self, internal_name, external_name):
     REQUEST('CodeCompleteSetPopularAPI',
             'source.request.codecomplete.setpopularapi'),
     REQUEST('CodeCompleteSetCustom', 'source.request.codecomplete.setcustom'),
+    REQUEST('SignatureHelp', 'source.request.signaturehelp'),
     REQUEST('TypeContextInfo', 'source.request.typecontextinfo'),
     REQUEST('ConformingMethodList', 'source.request.conformingmethods'),
     REQUEST('ActiveRegions', 'source.request.activeregions'),
@@ -351,6 +357,14 @@ def __init__(self, internal_name, external_name):
          'source.lang.swift.decl.function.accessor.init'),
     KIND('RefAccessorInit',
          'source.lang.swift.ref.function.accessor.init'),
+    KIND('DeclAccessorMutate',
+         'source.lang.swift.decl.function.accessor.mutate'),
+    KIND('RefAccessorMutate',
+         'source.lang.swift.ref.function.accessor.mutate'),
+    KIND('DeclAccessorBorrow',
+         'source.lang.swift.decl.function.accessor.borrow'),
+    KIND('RefAccessorBorrow',
+         'source.lang.swift.ref.function.accessor.borrow'),
     KIND('DeclConstructor', 'source.lang.swift.decl.function.constructor'),
     KIND('RefConstructor', 'source.lang.swift.ref.function.constructor'),
     KIND('DeclDestructor', 'source.lang.swift.decl.function.destructor'),
@@ -476,6 +490,7 @@ def __init__(self, internal_name, external_name):
     KIND('DiagNote', 'source.diagnostic.severity.note'),
     KIND('DiagWarning', 'source.diagnostic.severity.warning'),
     KIND('DiagError', 'source.diagnostic.severity.error'),
+    KIND('DiagRemark', 'source.diagnostic.severity.remark'),
     KIND('DiagDeprecation', 'source.diagnostic.category.deprecation'),
     KIND('DiagNoUsage', 'source.diagnostic.category.no_usage'),
     KIND('CodeCompletionEverything', 'source.codecompletion.everything'),
diff --git a/utils/line-directive b/utils/line-directive
index b87f66d268d80..2f0326942a089 100755
--- a/utils/line-directive
+++ b/utils/line-directive
@@ -208,11 +208,8 @@ def map_line_from_source_file(source_filename, source_line_num,
 
 def read_response_file(file_path):
     with open(file_path, 'r') as files:
-        # "Make an iterator out of shlex.shlex.get_token, then consume items
-        # until it returns None." (Then eagerly convert the result to a list so
-        # that we can close the file.)
-        return list(iter(shlex.shlex(files, file_path, posix=True).get_token,
-                         None))
+        # Read a response file and return a list of files (one per line).
+        return [line.strip() for line in files if line.strip()]
 
 
 def expand_response_files(files):
@@ -683,16 +680,21 @@ def run():
         # delegates to the Win32 CreateProcess API. Unix systems handle
         # non-normalized paths, so don't have this problem.
         # Arguments passed to the process are normalized by the process.
-        command_args = expand_response_files(sys.argv[dashes + 1:])
+        command_args = sys.argv[dashes + 1:]
         command_args[0] = os.path.normpath(command_args[0])
 
-        command = subprocess.Popen(
-            command_args,
-            stderr=subprocess.STDOUT,
-            stdout=subprocess.PIPE,
-            universal_newlines=True,
-            encoding='UTF-8'
-        )
+        try:
+            command = subprocess.Popen(
+                command_args,
+                stderr=subprocess.STDOUT,
+                stdout=subprocess.PIPE,
+                universal_newlines=True,
+                encoding='UTF-8'
+            )
+        except Exception as e:
+            sys.stderr.write(f"Error executing command: {e}\n")
+            sys.stderr.write(f"Command: {' '.join(shlex.quote(arg) for arg in command_args)}\n")
+            sys.exit(1)
 
         sources = '(?P<file>' + '|'.join(re.escape(s) for s in sources) + ')'
 
@@ -731,7 +733,12 @@ def run():
                         m.group('tail'))
             sys.stdout.write(output)
 
-        sys.exit(command.wait())
+        exit_code = command.wait()
+        if exit_code != 0:
+            sys.stderr.write(f"Command failed with exit code {exit_code}\n")
+            sys.stderr.write(f"Command: {' '.join(shlex.quote(arg) for arg in command_args)}\n")
+
+        sys.exit(exit_code)
 
 
 if __name__ == '__main__':
diff --git a/utils/lldb/lldbSwiftDataFormatters.py b/utils/lldb/lldbSwiftDataFormatters.py
index 0443b1c91a346..6f19d23e50dda 100644
--- a/utils/lldb/lldbSwiftDataFormatters.py
+++ b/utils/lldb/lldbSwiftDataFormatters.py
@@ -62,10 +62,10 @@ def SmallBitVectorSummaryProvider(valobj, internal_dict):
 
 class DemangleNodePayloadKind(Enum):
     NONE = 0
-    TEXT = 1
-    INDEX = 2
-    ONE_CHILD = 3
-    TWO_CHILDREN = 4
+    ONE_CHILD = 1
+    TWO_CHILDREN = 2
+    TEXT = 3
+    INDEX = 4
     MANY_CHILDREN = 5
 
 
diff --git a/utils/remote-run b/utils/remote-run
index 2e28893ab63cd..87b9c8e0b082a 100755
--- a/utils/remote-run
+++ b/utils/remote-run
@@ -203,7 +203,7 @@ class RemoteCommandRunner(CommandRunner):
                 [quote(arg) for arg in command])
 
     def rsync_invocation(self, source, dest):
-        return ['/usr/bin/rsync', '-arRz', '--files-from=-',
+        return ['rsync', '-arRz', '--files-from=-',
                 '-e', ' '.join([quote(x) for x in
                                 ['/usr/bin/ssh'] +
                                 self.common_options(port_flag='-p')]),
@@ -221,7 +221,7 @@ class LocalCommandRunner(CommandRunner):
         return command
 
     def rsync_invocation(self, source, dest):
-        return ['/usr/bin/rsync', '-arz', '--files-from=-', source, dest]
+        return ['rsync', '-arz', '--files-from=-', source, dest]
 
     def rsync_from_invocation(self, source, dest):
         return self.rsync_invocation(source, dest)
diff --git a/utils/run-test b/utils/run-test
index 2a40dea8670aa..a294b589af020 100755
--- a/utils/run-test
+++ b/utils/run-test
@@ -25,6 +25,7 @@ TEST_MODES = [
     'optimize_none',
     'optimize',
     'optimize_unchecked',
+    'optimize_none_with_opaque_values',
     'only_executable',
     'only_non_executable',
 ]
@@ -159,6 +160,9 @@ def main():
     parser.add_argument("--unified", action="store_true",
                         help="The build directory is an unified LLVM build, "
                              "not a standalone Swift build")
+    parser.add_argument("--update-tests", action="store_true",
+                        help="Invoke lit with --update-tests to auto-repair failing tests "
+                             "(when possible)")
 
     args = parser.parse_args()
 
@@ -279,6 +283,9 @@ def main():
     if args.filter:
         test_args += ['--filter', args.filter]
 
+    if args.update_tests:
+        test_args.append('--update-tests')
+
     test_cmd = [sys.executable, args.lit] + test_args + paths
 
     # Do execute test
diff --git a/utils/swift-darwin-postprocess.py b/utils/swift-darwin-postprocess.py
index 5ec12d565adaa..2488687576dbf 100755
--- a/utils/swift-darwin-postprocess.py
+++ b/utils/swift-darwin-postprocess.py
@@ -13,11 +13,18 @@
 get_task_allow_plist = os.path.join(utils, 'get-task-allow.plist')
 
 
+def file_path(string):
+    if os.path.isfile(string):
+        return string
+    else:
+        raise argparse.ArgumentTypeError(f"{string} is not a valid path")
+
+
 def main(arguments):
     parser = argparse.ArgumentParser(
         description='Postprocess binaries to prepare for \
                      their execution on Darwin platforms')
-    parser.add_argument('bins', nargs='+', help='one or more binary files')
+    parser.add_argument('bins', type=file_path, nargs='+', help='one or more binary files')
 
     args = parser.parse_args(arguments)
 
@@ -37,12 +44,12 @@ def unrpathize(filename):
         # `dyldinfo` has been replaced with `dyld_info`, so we try it first
         # before falling back to `dyldinfo`
         dylibsOutput = subprocess.check_output(
-            ['xcrun', 'dyld_info', '-dependents', filename],
+            ['/usr/bin/xcrun', 'dyld_info', '-dependents', filename],
             universal_newlines=True)
     except subprocess.CalledProcessError:
         sys.stderr.write("falling back to 'xcrun dyldinfo' ...\n")
         dylibsOutput = subprocess.check_output(
-            ['xcrun', 'dyldinfo', '-dylibs', filename],
+            ['/usr/bin/xcrun', 'dyldinfo', '-dylibs', filename],
             universal_newlines=True)
 
     # Do not rewrite @rpath-relative load commands for these libraries:
@@ -71,7 +78,7 @@ def unrpathize(filename):
         r"(^|.*\s)(?P<path>@rpath/(?P<filename>libswift.*\.dylib))\s*$")
 
     # Build a command to invoke install_name_tool.
-    command = ['install_name_tool']
+    command = ['/usr/bin/xcrun', 'install_name_tool']
     for line in dylibsOutput.splitlines():
         match = dylib_regex.match(line)
         if match and match.group('filename') not in allow_list:
@@ -82,7 +89,7 @@ def unrpathize(filename):
 
     # Don't run the command if we didn't find any dylibs to change:
     # it's invalid to invoke install_name_tool without any operations.
-    if len(command) == 1:
+    if len(command) == 2:
         return
 
     # The last argument is the filename to operate on.
diff --git a/utils/swift-rpathize.py b/utils/swift-rpathize.py
index cbf5f68a09a9d..6d364ebac4d0f 100755
--- a/utils/swift-rpathize.py
+++ b/utils/swift-rpathize.py
@@ -39,15 +39,23 @@
 # /usr/lib/swift and changes them to use @rpath.
 
 import argparse
+import os
 import re
 import subprocess
 import sys
 
 
+def file_path(string):
+    if os.path.isfile(string):
+        return string
+    else:
+        raise argparse.ArgumentTypeError(f"{string} is not a valid path")
+
+
 def main(arguments):
     parser = argparse.ArgumentParser(
         description='Change absolute install names to use @rpath')
-    parser.add_argument('bin', help='the binary')
+    parser.add_argument('bin', type=file_path, help='the binary')
 
     args = parser.parse_args(arguments)
     rpathize(args.bin)
@@ -60,12 +68,12 @@ def rpathize(filename):
         # `dyldinfo` has been replaced with `dyld_info`, so we try it first
         # before falling back to `dyldinfo`
         dylibsOutput = subprocess.check_output(
-            ['xcrun', 'dyld_info', '-dependents', filename],
+            ['/usr/bin/xcrun', 'dyld_info', '-dependents', filename],
             universal_newlines=True)
     except subprocess.CalledProcessError:
         sys.stderr.write("falling back to 'xcrun dyldinfo' ...\n")
         dylibsOutput = subprocess.check_output(
-            ['xcrun', 'dyldinfo', '-dylibs', filename],
+            ['/usr/bin/xcrun', 'dyldinfo', '-dylibs', filename],
             universal_newlines=True)
 
     # The output from dyldinfo -dylibs is a line of header followed by one
@@ -74,7 +82,7 @@ def rpathize(filename):
         r"(^|.*\s)(?P<path>/usr/lib/swift/(?P<filename>.*\.dylib))\s*$")
 
     # Build a command to invoke install_name_tool.
-    command = ['install_name_tool']
+    command = ['/usr/bin/xcrun', 'install_name_tool']
     for line in dylibsOutput.splitlines():
         match = dylib_regex.match(line)
         if match:
@@ -85,7 +93,7 @@ def rpathize(filename):
 
     # Don't run the command if we didn't find any dylibs to change:
     # it's invalid to invoke install_name_tool without any operations.
-    if len(command) == 1:
+    if len(command) == 2:
         return
 
     # The last argument is the filename to operate on.
diff --git a/utils/swift-xcodegen/Package.resolved b/utils/swift-xcodegen/Package.resolved
index dde580f930605..64276823de484 100644
--- a/utils/swift-xcodegen/Package.resolved
+++ b/utils/swift-xcodegen/Package.resolved
@@ -5,8 +5,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-argument-parser.git",
       "state" : {
-        "revision" : "0fbc8848e389af3bb55c182bc19ca9d5dc2f255b",
-        "version" : "1.4.0"
+        "revision" : "41982a3656a71c768319979febd796c6fd111d5c",
+        "version" : "1.5.0"
       }
     },
     {
@@ -15,16 +15,16 @@
       "location" : "https://github.com/swiftlang/swift-driver",
       "state" : {
         "branch" : "main",
-        "revision" : "c647e91574122f2b104d294ab1ec5baadaa1aa95"
+        "revision" : "974a26ed254ae0bd1e2da678de66afe819c09cf3"
       }
     },
     {
       "identity" : "swift-llbuild",
       "kind" : "remoteSourceControl",
-      "location" : "https://github.com/apple/swift-llbuild.git",
+      "location" : "https://github.com/swiftlang/swift-llbuild.git",
       "state" : {
         "branch" : "main",
-        "revision" : "e4ea3d267974bf75e637ec65c0b753558b22a451"
+        "revision" : "19db29ba20592429bcf74c672f6c44f5b035bec9"
       }
     },
     {
@@ -32,26 +32,17 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/swiftlang/swift-toolchain-sqlite",
       "state" : {
-        "revision" : "9cff1f87bf66f6642ba510d42da7a3bb10006bba",
-        "version" : "0.1.1"
+        "revision" : "b45b80b943e88db3cb8ddea798fa3fa9912375ff",
+        "version" : "1.0.7"
       }
     },
     {
       "identity" : "swift-tools-support-core",
       "kind" : "remoteSourceControl",
-      "location" : "https://github.com/apple/swift-tools-support-core.git",
+      "location" : "https://github.com/swiftlang/swift-tools-support-core.git",
       "state" : {
         "branch" : "main",
-        "revision" : "a76104dbd3c3fff41adb70bc7e917a4b2d076cef"
-      }
-    },
-    {
-      "identity" : "yams",
-      "kind" : "remoteSourceControl",
-      "location" : "https://github.com/jpsim/Yams.git",
-      "state" : {
-        "revision" : "0d9ee7ea8c4ebd4a489ad7a73d5c6cad55d6fed3",
-        "version" : "5.0.6"
+        "revision" : "e8fbc8b05a155f311b862178d92d043afb216fe3"
       }
     }
   ],
diff --git a/utils/swift-xcodegen/Package.swift b/utils/swift-xcodegen/Package.swift
index 7b7d085a1eb37..7d965b03dfabf 100644
--- a/utils/swift-xcodegen/Package.swift
+++ b/utils/swift-xcodegen/Package.swift
@@ -8,13 +8,14 @@ let package = Package(
     name: "swift-xcodegen",
     platforms: [.macOS(.v13)],
     targets: [
-        .target(name: "Xcodeproj", exclude: ["README.md"]),
         .target(
             name: "SwiftXcodeGen",
             dependencies: [
               .product(name: "ArgumentParser", package: "swift-argument-parser"),
               .product(name: "SwiftOptions", package: "swift-driver"),
-              "Xcodeproj"
+            ],
+            exclude: [
+              "Xcodeproj/README.md",
             ],
             swiftSettings: [
               .enableExperimentalFeature("StrictConcurrency")
diff --git a/utils/swift-xcodegen/README.md b/utils/swift-xcodegen/README.md
index 8a1f28c6573db..3f90f3a0af5b2 100644
--- a/utils/swift-xcodegen/README.md
+++ b/utils/swift-xcodegen/README.md
@@ -94,11 +94,7 @@ PROJECT CONFIGURATION:
                           Requires Xcode 16: Enables the use of "buildable folders", allowing
                           folder references to be used for compatible targets. This allows new
                           source files to be added to a target without needing to regenerate the
-                          project.
-
-                          Only supported for targets that have no per-file build settings. This
-                          unfortunately means some Clang targes such as 'lib/Basic' and 'stdlib'
-                          cannot currently use buildable folders. (default: --buildable-folders)
+                          project. (default: --buildable-folders)
 
   --runtimes-build-dir <runtimes-build-dir>
                           Experimental: The path to a build directory for the new 'Runtimes/'
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/ClangBuildArgsProvider.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/ClangBuildArgsProvider.swift
index f7791dd88d0b3..4d9075406ca64 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/ClangBuildArgsProvider.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/ClangBuildArgsProvider.swift
@@ -37,11 +37,12 @@ struct ClangBuildArgsProvider {
                           (output: AbsolutePath?, args: [Command.Argument])] = [:]
     for command in parsed {
       guard command.command.executable.knownCommand == .clang,
-            let relFilePath = command.file.removingPrefix(repoPath)
+            command.file.exists,
+            let relFilePath = command.file.realPath.removingPrefix(repoPath)
       else {
         continue
       }
-      let output = command.output.map { command.directory.appending($0) }
+      let output = command.output.map { $0.absolute(in: command.directory) }
       if let existing = commandsToAdd[relFilePath],
          let existingOutput = existing.output,
           output == nil || existingOutput.exists || !output!.exists {
@@ -50,17 +51,24 @@ struct ClangBuildArgsProvider {
       commandsToAdd[relFilePath] = (output, command.command.args)
     }
     for (path, (output, commandArgs)) in commandsToAdd {
-      // Only include arguments that have known flags.
-      args.insert(commandArgs.filter({ $0.flag != nil }), for: path)
+      let commandArgs = commandArgs.filter { arg in
+        // Only include arguments that have known flags.
+        // Ignore `-fdiagnostics-color`, we don't want ANSI escape sequences
+        // in Xcode build logs.
+        guard let flag = arg.flag, flag != .fDiagnosticsColor else {
+          return false
+        }
+        return true
+      }
+      args.insert(commandArgs, for: path)
       outputs[path] = output
     }
   }
 
   /// Retrieve the arguments at a given path, including those in the parent.
   func getArgs(for path: RelativePath) -> BuildArgs {
-    // Sort the arguments to get a deterministic ordering.
     // FIXME: We ought to get the command from the arg tree.
-    .init(for: .clang, args: args.getArgs(for: path).sorted())
+    .init(for: .clang, args: args.getArgs(for: path))
   }
 
   /// Retrieve the arguments at a given path, excluding those already covered
@@ -68,7 +76,7 @@ struct ClangBuildArgsProvider {
   func getUniqueArgs(
     for path: RelativePath, parent: RelativePath, infer: Bool = false
   ) -> BuildArgs {
-    var fileArgs: Set<Command.Argument> = []
+    var fileArgs: [Command.Argument] = []
     if hasBuildArgs(for: path) {
       fileArgs = args.getUniqueArgs(for: path, parent: parent)
     } else if infer {
@@ -78,14 +86,8 @@ struct ClangBuildArgsProvider {
         fileArgs = args.getUniqueArgs(for: component, parent: parent)
       }
     }
-    // Sort the arguments to get a deterministic ordering.
     // FIXME: We ought to get the command from the arg tree.
-    return .init(for: .clang, args: fileArgs.sorted())
-  }
-
-  /// Whether the given path has any unique args not covered by `parent`.
-  func hasUniqueArgs(for path: RelativePath, parent: RelativePath) -> Bool {
-    args.hasUniqueArgs(for: path, parent: parent)
+    return .init(for: .clang, args: fileArgs)
   }
 
   /// Whether the given file has build arguments.
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/CommandArgTree.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/CommandArgTree.swift
index f476d30ce7145..766b74ed0807d 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/CommandArgTree.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/CommandArgTree.swift
@@ -11,31 +11,33 @@
 //===----------------------------------------------------------------------===//
 
 /// A tree of compile command arguments, indexed by path such that those unique
-/// to a particular file can be queried, with common arguments associated
-/// with a common parent.
+/// to a particular file can be queried, with common-prefixed arguments
+/// associated with a common parent.
 struct CommandArgTree {
-  private var storage: [RelativePath: Set<Command.Argument>]
+  private var storage: [RelativePath: [Command.Argument]]
 
   init() {
     self.storage = [:]
   }
 
   mutating func insert(_ args: [Command.Argument], for path: RelativePath) {
-    let args = Set(args)
     for component in path.stackedComponents {
       // If we haven't added any arguments, add them. If we're adding arguments
       // for the file itself, this is the only way we'll add arguments,
-      // otherwise we can form an intersection with the other arguments.
+      // otherwise we can form a common prefix with the other arguments.
       let inserted = storage.insertValue(args, for: component)
       guard !inserted && component != path else { continue }
 
-      // We use subscript(_:default:) to mutate in-place without CoW.
-      storage[component, default: []].formIntersection(args)
+      // We use withValue(for:default:) to mutate in-place without CoW.
+      storage.withValue(for: component, default: []) { existingArgs in
+        let slice = existingArgs.commonPrefix(with: args)
+        existingArgs.removeSubrange(slice.endIndex...)
+      }
     }
   }
 
   /// Retrieve the arguments at a given path, including those in the parent.
-  func getArgs(for path: RelativePath) -> Set<Command.Argument> {
+  func getArgs(for path: RelativePath) -> [Command.Argument] {
     storage[path] ?? []
   }
 
@@ -43,17 +45,9 @@ struct CommandArgTree {
   /// by a given parent.
   func getUniqueArgs(
     for path: RelativePath, parent: RelativePath
-  ) -> Set<Command.Argument> {
-    getArgs(for: path).subtracting(getArgs(for: parent))
-  }
-
-  /// Whether the given path has any unique args not covered by `parent`.
-  func hasUniqueArgs(for path: RelativePath, parent: RelativePath) -> Bool {
-    let args = getArgs(for: path)
-    guard !args.isEmpty else { return false }
-    // Assuming `parent` is an ancestor of path, the arguments for parent is
-    // guaranteed to be a subset of the arguments for `path`. As such, we
-    // only have to compare sizes here.
-    return args.count != getArgs(for: parent).count
+  ) -> [Command.Argument] {
+    let childArgs = getArgs(for: path)
+    let parentArgs = getArgs(for: parent)
+    return Array(childArgs[parentArgs.count...])
   }
 }
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/SwiftTargets.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/SwiftTargets.swift
index 01bc7fda399c9..0d7874e421f6c 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/SwiftTargets.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/BuildArgs/SwiftTargets.swift
@@ -17,7 +17,6 @@ struct SwiftTargets {
   private var dependenciesByTargetName: [String: Set<String>] = [:]
   private var targetsByName: [String: SwiftTarget] = [:]
   private var targetsByOutput: [String: SwiftTarget] = [:]
-  private var addedFiles: Set<RelativePath> = []
 
   // Track some state for debugging
   private var debugLogUnknownFlags: Set<String> = []
@@ -125,10 +124,14 @@ struct SwiftTargets {
         // A relative path is for a file in the build directory, it's external.
         let abs = buildDir.path.appending(r)
         guard abs.exists else { continue }
-        sources.externalSources.append(abs)
+        sources.externalSources.append(abs.realPath)
 
       case .absolute(let a):
-        guard a.exists, let rel = a.removingPrefix(buildDir.repoPath) else {
+        guard a.exists else { continue }
+        // Symlinks shouldn't really be a concern here, but we need to realpath
+        // in order to canonicalize the casing.
+        let a = a.realPath
+        guard let rel = a.removingPrefix(buildDir.repoPath) else {
           sources.externalSources.append(a)
           continue
         }
@@ -204,22 +207,10 @@ struct SwiftTargets {
     var buildRule: SwiftTarget.BuildRule?
     var emitModuleRule: SwiftTarget.EmitModuleRule?
     if forBuild && !repoSources.isEmpty {
-      // Bail if we've already recorded a target with one of these inputs.
-      // TODO: Attempt to merge?
-      // TODO: Should we be doing this later?
-      for input in repoSources {
-        guard addedFiles.insert(input).inserted else {
-          log.debug("""
-            ! Skipping '\(name)' with output '\(primaryOutput)'; \
-            contains input '\(input)' already added
-            """)
-          return
-        }
-      }
       // We've already ensured that `repoSources` is non-empty.
-      let parent = repoSources.commonAncestor!
       buildRule = .init(
-        parentPath: parent, sources: sources, buildArgs: buildArgs
+        parentPath: repoSources.commonAncestor!, sources: sources,
+        buildArgs: buildArgs
       )
     }
     if forModule {
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/Command.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/Command.swift
index d78699216b18f..e2bbf7f514f37 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/Command.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/Command.swift
@@ -240,47 +240,3 @@ extension Command.Flag: CustomStringConvertible {
 extension Command.Option: CustomStringConvertible {
   var description: String { printed }
 }
-
-// MARK: Comparable
-// We sort the resulting command-line arguments to ensure deterministic
-// ordering.
-
-extension Command.Flag: Comparable {
-  static func < (lhs: Self, rhs: Self) -> Bool {
-    guard lhs.dash == rhs.dash else {
-      return lhs.dash < rhs.dash
-    }
-    return lhs.name.rawValue < rhs.name.rawValue
-  }
-}
-
-extension Command.Option: Comparable {
-  static func < (lhs: Self, rhs: Self) -> Bool {
-    guard lhs.flag == rhs.flag else {
-      return lhs.flag < rhs.flag
-    }
-    guard lhs.spacing == rhs.spacing else {
-      return lhs.spacing < rhs.spacing
-    }
-    return lhs.value < rhs.value
-  }
-}
-
-extension Command.Argument: Comparable {
-  static func < (lhs: Self, rhs: Self) -> Bool {
-    switch (lhs, rhs) {
-    // Sort flags < options < values
-    case (.flag, .option):  true
-    case (.flag, .value):   true
-    case (.option, .value): true
-
-    case (.option, .flag):  false
-    case (.value, .flag):   false
-    case (.value, .option): false
-
-    case (.flag(let lhs), .flag(let rhs)):     lhs < rhs
-    case (.option(let lhs), .option(let rhs)): lhs < rhs
-    case (.value(let lhs), .value(let rhs)):   lhs < rhs
-    }
-  }
-}
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/CommandParser.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/CommandParser.swift
index a1736aecd1475..c91313453527f 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/CommandParser.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/CommandParser.swift
@@ -13,6 +13,7 @@
 struct CommandParser {
   private var input: ByteScanner
   private var knownCommand: KnownCommand?
+  private var stopAtShellOperator = false
 
   private init(_ input: UnsafeBufferPointer<UInt8>) {
     self.input = ByteScanner(input)
@@ -26,6 +27,8 @@ struct CommandParser {
     }
   }
 
+  /// Parse an arbitrary shell command, returning the first single invocation
+  /// of a known command.
   static func parseKnownCommandOnly(_ input: String) throws -> Command? {
     var input = input
     return try input.withUTF8 { bytes in
@@ -35,6 +38,9 @@ struct CommandParser {
       ) else {
         return nil
       }
+      // We're parsing an arbitrary shell command so stop if we hit a shell
+      // operator like '&&'
+      parser.stopAtShellOperator = true
       return Command(executable: executable, args: try parser.consumeArguments())
     }
   }
@@ -62,7 +68,7 @@ struct CommandParser {
   ) throws -> AnyPath? {
     var executable: AnyPath
     repeat {
-      guard let executableUTF8 = try input.consumeElement() else {
+      guard let executableUTF8 = try consumeElement() else {
         return nil
       }
       executable = AnyPath(String(utf8: executableUTF8))
@@ -119,17 +125,27 @@ fileprivate extension ByteScanner.Consumer {
   }
 }
 
-fileprivate extension ByteScanner {
-  mutating func consumeElement() throws -> Bytes? {
+extension CommandParser {
+  mutating func consumeElement() throws -> ByteScanner.Bytes? {
     // Eat any leading whitespace.
-    skip(while: \.isSpaceOrTab)
+    input.skip(while: \.isSpaceOrTab)
 
     // If we're now at the end of the input, nothing can be parsed.
-    guard hasInput else { return nil }
-
-    // Consume the element, stopping at the first space.
-    return try consume(using: { consumer in
-      switch consumer.peek {
+    guard input.hasInput else { return nil }
+
+    // Consume the element, stopping at the first space or shell operator.
+    let start = input.cursor
+    let elt = try input.consume(using: { consumer in
+      guard let char = consumer.peek else { return false }
+      if stopAtShellOperator {
+        switch char {
+        case "<", ">", "(", ")", "|", "&", ";":
+          return false
+        default:
+          break
+        }
+      }
+      switch char {
       case \.isSpaceOrTab:
         return false
       case "\"":
@@ -139,6 +155,9 @@ fileprivate extension ByteScanner {
         return consumer.consumeUnescaped()
       }
     })
+    // Note that we may have an empty element while still moving the cursor
+    // for e.g '-I ""', which is an option with an empty value.
+    return start != input.cursor ? elt : nil
   }
 }
 
@@ -167,7 +186,7 @@ extension CommandParser {
       return makeOption(spacing: .unspaced, String(utf8: option.remaining))
     }
     if spacing.contains(.spaced), !option.hasInput,
-       let value = try input.consumeElement() {
+       let value = try consumeElement() {
       return makeOption(spacing: .spaced, String(utf8: value))
     }
     return option.empty ? .flag(flag) : nil
@@ -188,7 +207,7 @@ extension CommandParser {
   }
 
   mutating func consumeArgument() throws -> Command.Argument? {
-    guard let element = try input.consumeElement() else { return nil }
+    guard let element = try consumeElement() else { return nil }
     return try element.withUnsafeBytes { bytes in
       var option = ByteScanner(bytes)
       var numDashes = 0
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/CompileCommands.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/CompileCommands.swift
index 64b04c73a81c4..09c84e442fb96 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/CompileCommands.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/CompileCommands.swift
@@ -27,7 +27,7 @@ extension CompileCommands {
   struct Element: Decodable {
     var directory: AbsolutePath
     var file: AbsolutePath
-    var output: RelativePath?
+    var output: AnyPath?
     var command: Command
   }
 }
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/KnownCommand.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/KnownCommand.swift
index 90edf11c3bc7e..8e227c740634c 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/KnownCommand.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Command/KnownCommand.swift
@@ -128,6 +128,7 @@ extension Command.Flag {
   static let isystem = dash("isystem")
   static let isysroot = dash("isysroot")
   static let f = dash("f")
+  static let fDiagnosticsColor = dash("fdiagnostics-color")
   static let U = dash("U")
   static let W = dash("W")
   static let std = dash("std")
@@ -147,12 +148,22 @@ extension Command.Flag {
     swiftc(.experimentalSkipNonInlinableFunctionBodies)
   static let experimentalSkipNonInlinableFunctionBodiesWithoutTypes = 
     swiftc(.experimentalSkipNonInlinableFunctionBodiesWithoutTypes)
+  static let enableUpcomingFeature =
+    swiftc(.enableUpcomingFeature)
+  static let disableExperimentalFeature =
+    swiftc(.disableExperimentalFeature)
+  static let disableUpcomingFeature =
+    swiftc(.disableUpcomingFeature)
   static let F =
     swiftc(.F)
   static let Fsystem =
     swiftc(.Fsystem)
+  static let libraryLevel =
+    swiftc(.libraryLevel)
   static let moduleName =
     swiftc(.moduleName)
+  static let moduleAbiName =
+    swiftc(.moduleAbiName)
   static let moduleLinkName =
     swiftc(.moduleLinkName)
   static let nostdimport =
@@ -171,8 +182,12 @@ extension Command.Flag {
     swiftc(.runtimeCompatibilityVersion)
   static let sdk =
     swiftc(.sdk)
+  static let strictMemorySafety =
+    swiftc(.strictMemorySafety)
   static let swiftVersion =
     swiftc(.swiftVersion)
+  static let warnImplicitOverrides =
+    swiftc(.warnImplicitOverrides)
   static let wholeModuleOptimization =
     swiftc(.wholeModuleOptimization)
   static let wmo =
@@ -197,6 +212,8 @@ extension KnownCommand {
     // FIXME: We ought to see if we can get away with preserving unknown flags.
     .init(.f, option: .unspaced),
 
+    .init(.fDiagnosticsColor),
+
     // FIXME: Really we ought to map to Xcode's SDK
     .init(.isystem, option: .unspaced, .spaced),
     .init(.isysroot, option: .unspaced, .spaced),
@@ -236,13 +253,18 @@ extension KnownCommand {
     .experimentalSkipAllFunctionBodies,
     .experimentalSkipNonInlinableFunctionBodies,
     .experimentalSkipNonInlinableFunctionBodiesWithoutTypes,
+    .enableUpcomingFeature,
+    .disableExperimentalFeature,
+    .disableUpcomingFeature,
     .F,
     .Fsystem,
     .I,
     .nostdimport,
     .O,
     .Onone,
+    .libraryLevel,
     .moduleName,
+    .moduleAbiName,
     .moduleLinkName,
     .packageName,
     .parseAsLibrary,
@@ -250,7 +272,9 @@ extension KnownCommand {
     .runtimeCompatibilityVersion,
     .target,
     .sdk,
+    .strictMemorySafety,
     .swiftVersion,
+    .warnImplicitOverrides,
     .wholeModuleOptimization,
     .wmo,
     .Xcc,
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ClangTarget.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ClangTarget.swift
index 419da7d2685cc..1c759f9679b88 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ClangTarget.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ClangTarget.swift
@@ -31,8 +31,8 @@ struct ClangTarget {
 }
 
 extension RepoBuildDir {
-  func getCSourceFilePaths(for path: RelativePath) throws -> [RelativePath] {
-    try getAllRepoSubpaths(of: path).filter(\.isCSourceLike)
+  func getClangSourceFilePaths(for path: RelativePath) throws -> [RelativePath] {
+    try getAllRepoSubpaths(of: path).filter(\.isClangSource)
   }
 
   func getHeaderFilePaths(for path: RelativePath) throws -> [RelativePath] {
@@ -45,7 +45,7 @@ extension RepoBuildDir {
     let path = target.path
     let name = target.name
 
-    let sourcePaths = try getCSourceFilePaths(for: path)
+    let sourcePaths = try getClangSourceFilePaths(for: path)
     let headers = try getHeaderFilePaths(for: path)
     if sourcePaths.isEmpty && headers.isEmpty {
       return nil
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ProjectGenerator.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ProjectGenerator.swift
index e9ca8a68d261b..4f78605fdb5a2 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ProjectGenerator.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ProjectGenerator.swift
@@ -10,7 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-import Xcodeproj
 import Darwin
 
 extension Xcode.Reference {
@@ -36,6 +35,7 @@ fileprivate final class ProjectGenerator {
   private var targets: [String: Xcode.Target] = [:]
   private var unbuildableSources: [RelativePath] = []
   private var runnableBuildTargets: [RunnableTarget: Xcode.Target] = [:]
+  private var buildableFolders: [RelativePath: Xcode.BuildableFolder] = [:]
 
   /// The group in which external files are stored.
   private var externalsGroup: Xcode.Group {
@@ -55,6 +55,13 @@ fileprivate final class ProjectGenerator {
   }()
   private var includeSubstitutions: Set<BuildArgs.PathSubstitution> = []
 
+  private lazy var unbuildablesTarget: Xcode.Target = {
+    generateBaseTarget(
+      "Unbuildables", at: ".", canUseBuildableFolder: false,
+      productType: .staticArchive, includeInAllTarget: false
+    )!
+  }()
+
   /// The main repo dir relative to the project.
   private lazy var mainRepoDirInProject: RelativePath? =
     spec.mainRepoDir.map { repoRelativePath.appending($0) }
@@ -206,6 +213,42 @@ fileprivate final class ProjectGenerator {
     return getOrCreateProjectRef(ref.withPath(repoRelativePath.appending(path)))
   }
 
+  @discardableResult
+  func getOrCreateRepoBuildableFolder(
+    at path: RelativePath
+  ) -> Xcode.BuildableFolder? {
+    guard let ref = getOrCreateRepoRef(.folder(path)) else { return nil }
+    let folder = ref.getOrCreateBuildableFolder(at: path)
+    buildableFolders[path] = folder
+
+    // Exclude any sources we don't want to handle.
+    do {
+      let excluded = try buildDir.getAllRepoSubpaths(of: path)
+        .filter(\.isExcludedSource)
+      folder.setTargets([], for: excluded)
+    } catch {
+      log.error("\(error)")
+    }
+
+    return folder
+  }
+
+  private func getParentBuildableFolder(
+    _ path: RelativePath
+  ) -> Xcode.BuildableFolder? {
+    // First check the mapping directly.
+    if let buildableFolder = buildableFolders[path] {
+      return buildableFolder
+    }
+    // Then check the parent.
+    if let parent = path.parentDir,
+        let buildableFolder = getParentBuildableFolder(parent) {
+      buildableFolders[path] = buildableFolder
+      return buildableFolder
+    }
+    return nil
+  }
+
   func getAllRepoSubpaths(of parent: RelativePath) throws -> [RelativePath] {
     try buildDir.getAllRepoSubpaths(of: parent)
   }
@@ -226,14 +269,15 @@ fileprivate final class ProjectGenerator {
       }
       return newName
     }()
-    var buildableFolder: Xcode.FileReference?
-    if let parentPath, !parentPath.components.isEmpty {
+    var buildableFolder: Xcode.BuildableFolder?
+    // Note that special targets like "Unbuildables" have an empty parent path.
+    if let parentPath, !parentPath.isEmpty {
       // If we've been asked to use buildable folders, see if we can create
       // a folder reference at the parent path. Otherwise, create a group at
       // the parent path. If we can't create either a folder or group, this is
       // nested in a folder reference and there's nothing we can do.
       if spec.useBuildableFolders && canUseBuildableFolder {
-        buildableFolder = getOrCreateRepoRef(.folder(parentPath))
+        buildableFolder = getOrCreateRepoBuildableFolder(at: parentPath)
       }
       guard buildableFolder != nil ||
               group(for: repoRelativePath.appending(parentPath)) != nil else {
@@ -263,6 +307,13 @@ fileprivate final class ProjectGenerator {
     // The product name needs to be unique across every project we generate
     // (to allow the combined workspaces to work), so add in the project name.
     target.buildSettings.common.PRODUCT_NAME = "\(self.name)_\(name)"
+
+    // Don't optimize or generate debug info, that will only slow down
+    // compilation; we don't actually care about the binary.
+    target.buildSettings.common.GCC_OPTIMIZATION_LEVEL = "0"
+    target.buildSettings.common.GCC_GENERATE_DEBUGGING_SYMBOLS = "NO"
+    target.buildSettings.common.GCC_WARN_64_TO_32_BIT_CONVERSION = "NO"
+
     return target
   }
 
@@ -299,10 +350,9 @@ fileprivate final class ProjectGenerator {
     at parentPath: RelativePath, sources: [RelativePath]
   ) throws -> Bool {
     // To use a buildable folder, all child sources need to be accounted for
-    // in the target. If we have any stray sources not part of the target,
-    // attempting to use a buildable folder would incorrectly include them.
-    // Additionally, special targets like "Unbuildables" have an empty parent
-    // path, avoid buildable folders for them.
+    // in the target. Ignore special targets like "Unbuildables" which have an
+    // empty parent path.
+    // TODO: We ought to be able to add stray sources as exclusions.
     guard spec.useBuildableFolders, !parentPath.isEmpty else { return false }
     let sources = Set(sources)
     return try getAllRepoSubpaths(of: parentPath)
@@ -312,20 +362,10 @@ fileprivate final class ProjectGenerator {
   /// Checks whether a given Clang target can be represented using a buildable
   /// folder.
   func canUseBuildableFolder(for clangTarget: ClangTarget) throws -> Bool {
-    // In addition to the standard checking, we also must not have any
-    // unbuildable sources or sources with unique arguments.
-    // TODO: To improve the coverage of buildable folders, we ought to start
-    // automatically splitting umbrella Clang targets like 'stdlib', since
-    // they currently always have files with unique args.
-    guard spec.useBuildableFolders, clangTarget.unbuildableSources.isEmpty else {
-      return false
-    }
-    let parent = clangTarget.parentPath
-    let hasConsistentArgs = try clangTarget.sources.allSatisfy {
-      try !buildDir.clangArgs.hasUniqueArgs(for: $0, parent: parent)
-    }
-    guard hasConsistentArgs else { return false }
-    return try canUseBuildableFolder(at: parent, sources: clangTarget.sources)
+    try canUseBuildableFolder(
+      at: clangTarget.parentPath,
+      sources: clangTarget.sources + clangTarget.unbuildableSources
+    )
   }
 
   func canUseBuildableFolder(
@@ -337,21 +377,62 @@ fileprivate final class ProjectGenerator {
     )
   }
 
-  func generateClangTarget(
-    _ targetInfo: ClangTarget, includeInAllTarget: Bool = true
+  func addSourcesPhaseToClangTarget(
+    _ target: Xcode.Target, sources: [RelativePath], targetPath: RelativePath
   ) throws {
+    let sourcesToBuild = target.addSourcesBuildPhase()
+    for source in sources {
+      var fileArgs = try buildDir.clangArgs.getUniqueArgs(
+        for: source, parent: targetPath, infer: spec.inferArgs
+      )
+      if !fileArgs.isEmpty {
+        applyBaseSubstitutions(to: &fileArgs)
+      }
+      // If we're using a buildable folder, the extra arguments are added to it
+      // directly.
+      if let buildableFolder = getParentBuildableFolder(source) {
+        if !fileArgs.isEmpty {
+          buildableFolder.setExtraCompilerArgs(
+            fileArgs.printedArgs, for: source, in: target
+          )
+        }
+        continue
+      }
+      // Otherwise we add as a file reference and add the arguments to the
+      // target.
+      guard let sourceRef = getOrCreateRepoRef(.file(source)) else {
+        continue
+      }
+      let buildFile = sourcesToBuild.addBuildFile(fileRef: sourceRef)
+
+      // Add any per-file settings.
+      buildFile.settings.COMPILER_FLAGS = fileArgs.printed
+    }
+  }
+
+  func generateClangTarget(_ targetInfo: ClangTarget) throws {
     let targetPath = targetInfo.parentPath
     guard checkNotExcluded(targetPath, for: "Clang target") else {
       return
     }
-    unbuildableSources += targetInfo.unbuildableSources
 
-    // Need to defer the addition of headers since the target may want to use
-    // a buildable folder.
+    // Need to defer the addition of headers and unbuildable sources since the
+    // target may want to use a buildable folder.
     defer {
-      for header in targetInfo.headers {
-        getOrCreateRepoRef(.file(header))
+      // If we're using a buildable folder, the headers are automatically
+      // included.
+      if let buildableFolder = getParentBuildableFolder(targetPath) {
+        buildableFolder.setTargets(
+          [unbuildablesTarget], for: targetInfo.unbuildableSources
+        )
+      } else {
+        for header in targetInfo.headers {
+          getOrCreateRepoRef(.file(header))
+        }
       }
+      // Add the unbuildable sources regardless of buildable folder since
+      // we still need the compiler arguments to be set.
+      unbuildableSources += targetInfo.unbuildableSources
     }
 
     // If we have no sources, we're done.
@@ -363,22 +444,20 @@ fileprivate final class ProjectGenerator {
         build args
         """)
       }
+      // Still create a buildable folder if we can. It won't have an associated
+      // target, but unbuildable sources may still be added as exceptions.
+      if try canUseBuildableFolder(for: targetInfo) {
+        getOrCreateRepoBuildableFolder(at: targetPath)
+      }
       return
     }
     let target = generateBaseTarget(
       targetInfo.name, at: targetPath,
       canUseBuildableFolder: try canUseBuildableFolder(for: targetInfo),
-      productType: .staticArchive,
-      includeInAllTarget: includeInAllTarget
+      productType: .staticArchive, includeInAllTarget: true
     )
     guard let target else { return }
 
-    // Don't optimize or generate debug info, that will only slow down
-    // compilation; we don't actually care about the binary.
-    target.buildSettings.common.GCC_OPTIMIZATION_LEVEL = "0"
-    target.buildSettings.common.GCC_GENERATE_DEBUGGING_SYMBOLS = "NO"
-    target.buildSettings.common.GCC_WARN_64_TO_32_BIT_CONVERSION = "NO"
-
     var libBuildArgs = try buildDir.clangArgs.getArgs(for: targetPath)
     applyBaseSubstitutions(to: &libBuildArgs)
 
@@ -390,23 +469,9 @@ fileprivate final class ProjectGenerator {
 
     target.buildSettings.common.OTHER_CPLUSPLUSFLAGS = libBuildArgs.printedArgs
 
-    let sourcesToBuild = target.addSourcesBuildPhase()
-
-    for source in targetInfo.sources {
-      guard let sourceRef = getOrCreateRepoRef(.file(source)) else {
-        continue
-      }
-      let buildFile = sourcesToBuild.addBuildFile(fileRef: sourceRef)
-
-      // Add any per-file settings.
-      var fileArgs = try buildDir.clangArgs.getUniqueArgs(
-        for: source, parent: targetPath, infer: spec.inferArgs
-      )
-      if !fileArgs.isEmpty {
-        applyBaseSubstitutions(to: &fileArgs)
-        buildFile.settings.COMPILER_FLAGS = fileArgs.printed
-      }
-    }
+    try addSourcesPhaseToClangTarget(
+      target, sources: targetInfo.sources, targetPath: targetPath
+    )
   }
 
   /// Record path substitutions for a given target.
@@ -760,14 +825,11 @@ fileprivate final class ProjectGenerator {
       try generateClangTarget(target)
     }
 
+    // Add any unbuildable sources to the special 'Unbuildables' target.
     if !unbuildableSources.isEmpty {
-      let target = ClangTarget(
-        name: "Unbuildables", 
-        parentPath: ".",
-        sources: unbuildableSources,
-        headers: []
+      try addSourcesPhaseToClangTarget(
+        unbuildablesTarget, sources: unbuildableSources, targetPath: "."
       )
-      try generateClangTarget(target, includeInAllTarget: false)
     }
 
     // Add targets for runnable targets if needed.
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ProjectSpec.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ProjectSpec.swift
index 4ebe2e6aa1a95..88eb2df2ac17f 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ProjectSpec.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/ProjectSpec.swift
@@ -212,14 +212,16 @@ extension ProjectSpec {
 
   public mutating func addClangTargets(
     below path: RelativePath, addingPrefix prefix: String? = nil,
-    mayHaveUnbuildableFiles: Bool = false
+    mayHaveUnbuildableFiles: Bool = false,
+    excluding excludedChildren: Set<RelativePath> = []
   ) {
     guard addClangTargets else { return }
     let originalPath = path
     guard let path = mapPath(path, for: "Clang targets") else { return }
     let absPath = repoRoot.appending(path)
     do {
-      for child in try absPath.getDirContents() {
+      for child in try absPath.getDirContents()
+      where !excludedChildren.contains(child) {
         guard absPath.appending(child).isDirectory else {
           continue
         }
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/SchemeGenerator.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/SchemeGenerator.swift
index 6a356f6d5b00b..aaa3231f21ecd 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/SchemeGenerator.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Generator/SchemeGenerator.swift
@@ -10,8 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-import Xcodeproj
-
 struct Scheme {
   var name: String
   var buildAction: BuildAction
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/AbsolutePath.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/AbsolutePath.swift
index 600a8378b0ff5..09738352b1e26 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/AbsolutePath.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/AbsolutePath.swift
@@ -52,7 +52,7 @@ public extension AbsolutePath {
     (try? FileManager.default.destinationOfSymbolicLink(atPath: rawPath)) != nil
   }
 
-  var resolvingSymlinks: Self {
+  var realPath: Self {
     guard let resolved = realpath(rawPath, nil) else { return self }
     defer {
       free(resolved)
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/AnyPath.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/AnyPath.swift
index 5ba0651f01739..4f40241f5685b 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/AnyPath.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/AnyPath.swift
@@ -74,9 +74,3 @@ extension AnyPath: ExpressibleByArgument {
     self.init(rawPath)
   }
 }
-
-extension StringProtocol {
-  func hasExtension(_ ext: FileExtension) -> Bool {
-    FilePath(String(self)).extension == ext.rawValue
-  }
-}
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/FileExtension.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/FileExtension.swift
index 1b2ea414a51db..6e558dee57f14 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/FileExtension.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/FileExtension.swift
@@ -11,17 +11,23 @@
 //===----------------------------------------------------------------------===//
 
 public enum FileExtension: String {
+  case asm
   case c
+  case cc
+  case cl
   case cpp
   case def
   case gyb
   case h
+  case inc
   case m
   case md
   case mm
   case modulemap
   case o
+  case proto
   case rst
+  case s
   case swift
   case swiftmodule
   case td
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/PathProtocol.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/PathProtocol.swift
index b44866b59e036..2000382b7f73c 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/PathProtocol.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Path/PathProtocol.swift
@@ -68,14 +68,11 @@ public extension PathProtocol {
     return RelativePath(result)
   }
 
-  func hasExtension(_ ext: FileExtension) -> Bool {
-    storage.extension == ext.rawValue
-  }
   func hasExtension(_ exts: FileExtension...) -> Bool {
     // Note that querying `.extension` involves re-parsing, so only do it
     // once here.
-    let ext = storage.extension
-    return exts.contains(where: { ext == $0.rawValue })
+    guard let pathExt = storage.extension else { return false }
+    return exts.contains(where: { $0.matches(pathExt) })
   }
 
   func starts(with other: Self) -> Bool {
@@ -127,12 +124,19 @@ extension PathProtocol {
     return false
   }
 
-  var isCSourceLike: Bool {
+  var isClangSource: Bool {
     hasExtension(.c, .cpp, .m, .mm)
   }
 
   var isSourceLike: Bool {
-    isCSourceLike || hasExtension(.swift)
+    isClangSource || hasExtension(.swift)
+  }
+
+  /// Checks whether this file a source file that should be excluded from
+  /// any generated targets.
+  var isExcludedSource: Bool {
+    // We don't get useful build arguments for these.
+    hasExtension(.asm, .s, .cc, .cl, .inc, .proto)
   }
 
   var isDocLike: Bool {
@@ -149,3 +153,16 @@ extension Collection where Element: PathProtocol {
     return result == first ? result.parentDir : result
   }
 }
+
+extension StringProtocol {
+  func hasExtension(_ exts: FileExtension...) -> Bool {
+    guard let pathExt = FilePath(String(self)).extension else { return false }
+    return exts.contains(where: { $0.matches(pathExt) })
+  }
+}
+
+extension FileExtension {
+  func matches(_ extStr: String) -> Bool {
+    rawValue.compare(extStr, options: .caseInsensitive) == .orderedSame
+  }
+}
diff --git a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Utils.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Utils.swift
index 3bdacad247997..d485edc0c0d16 100644
--- a/utils/swift-xcodegen/Sources/SwiftXcodeGen/Utils.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Utils.swift
@@ -34,6 +34,18 @@ extension Sequence {
   }
 }
 
+extension Collection where Element: Equatable {
+  func commonPrefix(with other: some Collection<Element>) -> SubSequence {
+    var (i, j) = (self.startIndex, other.startIndex)
+    while i < self.endIndex, j < other.endIndex {
+      guard self[i] == other[j] else { break }
+      self.formIndex(after: &i)
+      other.formIndex(after: &j)
+    }
+    return self[..<i]
+  }
+}
+
 extension String {
   init(utf8 buffer: UnsafeRawBufferPointer) {
     guard !buffer.isEmpty else {
diff --git a/utils/swift-xcodegen/Sources/Xcodeproj/PropertyList.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/PropertyList.swift
similarity index 100%
rename from utils/swift-xcodegen/Sources/Xcodeproj/PropertyList.swift
rename to utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/PropertyList.swift
diff --git a/utils/swift-xcodegen/Sources/Xcodeproj/PropertyListEncoder.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/PropertyListEncoder.swift
similarity index 100%
rename from utils/swift-xcodegen/Sources/Xcodeproj/PropertyListEncoder.swift
rename to utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/PropertyListEncoder.swift
diff --git a/utils/swift-xcodegen/Sources/Xcodeproj/README.md b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/README.md
similarity index 100%
rename from utils/swift-xcodegen/Sources/Xcodeproj/README.md
rename to utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/README.md
diff --git a/utils/swift-xcodegen/Sources/Xcodeproj/XcodeProjectModel.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/XcodeProjectModel.swift
similarity index 78%
rename from utils/swift-xcodegen/Sources/Xcodeproj/XcodeProjectModel.swift
rename to utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/XcodeProjectModel.swift
index 4d8246bd84c7e..a7130b54ab486 100644
--- a/utils/swift-xcodegen/Sources/Xcodeproj/XcodeProjectModel.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/XcodeProjectModel.swift
@@ -16,16 +16,16 @@
  and serialization to .xcodeproj plists.  There is no consistency checking to
  ensure, for example, that build settings have valid values, dependency cycles
  are not created, etc.
- 
+
  Everything here is geared toward supporting project generation.  The intended
  usage model is for custom logic to build up a project using Xcode terminology
  (e.g. "group", "reference", "target", "build phase"), but there is almost no
  provision for modifying the model after it has been built up.  The intent is
  to create it as desired from the start.
- 
+
  Rather than try to represent everything that Xcode's project model supports,
  the approach is to start small and to add functionality as needed.
- 
+
  Note that this API represents only the project model — there is no notion of
  workspaces, schemes, etc (although schemes are represented individually in a
  separate API).  The notion of build settings is also somewhat different from
@@ -37,11 +37,11 @@
  configuration of the settings, since most values are the same between Debug
  and Release.  Also, the build settings themselves are represented as structs
  of named fields, instead of dictionaries with arbitrary name strings as keys.
- 
+
  It is expected that some of these simplifications will need to be lifted over
  time, based on need.  That should be done carefully, however, to avoid ending
  up with an overly complicated model.
- 
+
  Some things that are incomplete in even this first model:
  - copy files build phases are incomplete
  - shell script build phases are incomplete
@@ -57,7 +57,7 @@
  */
 
 public struct Xcode {
-  
+
   /// An Xcode project, consisting of a tree of groups and file references,
   /// a list of targets, and some additional information.  Note that schemes
   /// are outside of the project data model.
@@ -74,7 +74,7 @@ public struct Xcode {
       self.projectDir = ""
       self.targets = []
     }
-    
+
     /// Creates and adds a new target (which does not initially have any
     /// build phases).
     public func addTarget(objectID: String? = nil, productType: Target.ProductType? = nil, name: String) -> Target {
@@ -94,7 +94,7 @@ public struct Xcode {
     /// Name of the reference, if different from the last path component
     /// (if not set, Xcode will use the last path component as the name).
     public var name: String?
-    
+
     /// Determines the base path for a reference's relative path (this is
     /// what for some reason is called a "source tree" in Xcode).
     public enum RefPathBase: String {
@@ -111,13 +111,13 @@ public struct Xcode {
       /// destination, or even an overridden build setting.
       case buildDir = "BUILT_PRODUCTS_DIR"
     }
-    
+
     init(path: String, pathBase: RefPathBase = .groupDir, name: String? = nil) {
       self.path = path
       self.pathBase = pathBase
       self.name = name
     }
-    
+
     /// Whether this is either a group or directory reference (blue folder).
     public var isDirectoryLike: Bool {
       if self is Xcode.Group {
@@ -129,13 +129,17 @@ public struct Xcode {
       return false
     }
   }
-  
+
   /// A reference to a file system entity (a file, folder, etc).
   public final class FileReference: Reference {
     public var objectID: String?
     public var fileType: String?
     public var isDirectory: Bool
-    public fileprivate(set) var isBuildableFolder: Bool = false
+    public private(set) unowned var buildableFolder: BuildableFolder?
+
+    public var isBuildableFolder: Bool {
+      buildableFolder != nil
+    }
 
     init(
       path: String, isDirectory: Bool, pathBase: RefPathBase = .groupDir,
@@ -146,14 +150,108 @@ public struct Xcode {
       self.objectID = objectID
       self.fileType = fileType
     }
+
+    /// Turn a folder reference into a buildable folder.
+    func getOrCreateBuildableFolder(at path: RelativePath) -> BuildableFolder {
+      precondition(isDirectory)
+      if let buildableFolder {
+        precondition(buildableFolder.path == path)
+        return buildableFolder
+      }
+      let folder = BuildableFolder(for: self, at: path)
+      buildableFolder = folder
+      return folder
+    }
   }
-  
+
+  public final class BuildableFolder {
+    public let ref: FileReference
+    public let path: RelativePath
+
+    /// The "primary" targets that are directly associated with the buildable
+    /// folder and are automatically inferred for every child source file.
+    private(set) var primaryTargets: Set<Xcode.Target> = []
+
+    /// Any source file specific compiler arguments.
+    private(set) var fileArgs: [FileInTarget: [String]] = [:]
+
+    /// Any non-default target memberships.
+    private(set) var targetMemberships: [RelativePath: Set<Xcode.Target>] = [:]
+
+    fileprivate init(for ref: FileReference, at path: RelativePath) {
+      self.ref = ref
+      self.path = path
+    }
+
+    /// Add a primary target to the buildable folder.
+    fileprivate func addPrimaryTarget(_ target: Target) {
+      primaryTargets.insert(target)
+    }
+
+    /// Map the given source file path such that it's relative to the
+    /// buildable folder itself.
+    private func mapSourcePath(_ sourcePath: RelativePath) -> RelativePath {
+      sourcePath.removingPrefix(path)!
+    }
+
+    /// Create the corresponding target exceptions for the buildable folder.
+    public func makeTargetExceptions() -> [TargetException] {
+      var result: [Xcode.Target: TargetException] = [:]
+      func getOrCreateException(for target: Xcode.Target) -> TargetException {
+        if let exception = result[target] {
+          return exception
+        }
+        let exception = TargetException(for: target)
+        result[target] = exception
+        return exception
+      }
+
+      // Populate target memberships.
+      for (path, targets) in targetMemberships.sorted(by: \.key.rawPath) {
+        // If it's missing from primary targets, it needs adding to the
+        // corresponding exception.
+        for missingPrimary in primaryTargets.subtracting(targets) {
+          getOrCreateException(for: missingPrimary).sources.append(path)
+        }
+        // Add to any non-primary targets.
+        for inSecondary in targets.subtracting(primaryTargets) {
+          getOrCreateException(for: inSecondary).sources.append(path)
+        }
+      }
+
+      // Populate per-file args.
+      for (fileInTarget, args) in fileArgs {
+        getOrCreateException(for: fileInTarget.target)
+          .extraCompilerArgs[fileInTarget.path] = args
+      }
+
+      return result.values.sorted(by: \.target.name)
+    }
+
+    /// Change the target membership for a given set of paths.
+    public func setTargets(
+      _ targets: Set<Xcode.Target>, for sourcePaths: [RelativePath]
+    ) {
+      for source in sourcePaths.map(mapSourcePath) {
+        targetMemberships[source] = targets
+      }
+    }
+
+    /// Set additional per-file arguments for a given path.
+    public func setExtraCompilerArgs(
+      _ args: [String], for sourcePath: RelativePath, in target: Xcode.Target
+    ) {
+      let key = FileInTarget(path: mapSourcePath(sourcePath), target: target)
+      fileArgs[key] = args
+    }
+  }
+
   /// A group that can contain References (FileReferences and other Groups).
   /// The resolved path of a group is used as the base path for any child
   /// references whose source tree type is GroupRelative.
   public final class Group: Reference {
     public var subitems = [Reference]()
-    
+
     /// Creates and appends a new Group to the list of subitems.
     /// The new group is returned so that it can be configured.
     @discardableResult
@@ -166,7 +264,7 @@ public struct Xcode {
       subitems.append(group)
       return group
     }
-    
+
     /// Creates and appends a new FileReference to the list of subitems.
     @discardableResult
     public func addFileReference(
@@ -193,7 +291,7 @@ public struct Xcode {
     public var buildPhases: [BuildPhase]
     public var productReference: FileReference?
     public var dependencies: [TargetDependency]
-    public private(set) var buildableFolders: [FileReference]
+    public private(set) var buildableFolders: [BuildableFolder]
     public enum ProductType: String {
       case application = "com.apple.product-type.application"
       case staticArchive = "com.apple.product-type.library.static"
@@ -212,11 +310,11 @@ public struct Xcode {
       self.dependencies = []
       self.buildableFolders = []
     }
-    
+
     // FIXME: There's a lot repetition in these methods; using generics to
     // try to avoid that raised other issues in terms of requirements on
     // the Reference class, though.
-    
+
     /// Adds a "headers" build phase, i.e. one that copies headers into a
     /// directory of the product, after suitable processing.
     @discardableResult
@@ -225,7 +323,7 @@ public struct Xcode {
       buildPhases.append(phase)
       return phase
     }
-    
+
     /// Adds a "sources" build phase, i.e. one that compiles sources and
     /// provides them to be linked into the executable code of the product.
     @discardableResult
@@ -234,7 +332,7 @@ public struct Xcode {
       buildPhases.append(phase)
       return phase
     }
-    
+
     /// Adds a "frameworks" build phase, i.e. one that links compiled code
     /// and libraries into the executable of the product.
     @discardableResult
@@ -243,7 +341,7 @@ public struct Xcode {
       buildPhases.append(phase)
       return phase
     }
-    
+
     /// Adds a "copy files" build phase, i.e. one that copies files to an
     /// arbitrary location relative to the product.
     @discardableResult
@@ -252,7 +350,7 @@ public struct Xcode {
       buildPhases.append(phase)
       return phase
     }
-    
+
     /// Adds a "shell script" build phase, i.e. one that runs a custom
     /// shell script as part of the build.
     @discardableResult
@@ -265,7 +363,7 @@ public struct Xcode {
       buildPhases.append(phase)
       return phase
     }
-    
+
     /// Adds a dependency on another target.
     /// FIXME: We do not check for cycles.  Should we?  This is an extremely
     /// minimal API so it's not clear that we should.
@@ -273,11 +371,10 @@ public struct Xcode {
       dependencies.append(TargetDependency(target: target))
     }
 
-    /// Turn a given folder reference into a buildable folder for this target.
-    public func addBuildableFolder(_ fileRef: FileReference) {
-      precondition(fileRef.isDirectory)
-      fileRef.isBuildableFolder = true
-      buildableFolders.append(fileRef)
+    /// Add an associated buildable folder to the target.
+    public func addBuildableFolder(_ folder: BuildableFolder) {
+      folder.addPrimaryTarget(self)
+      buildableFolders.append(folder)
     }
 
     /// A simple wrapper to prevent ownership cycles in the `dependencies`
@@ -286,11 +383,11 @@ public struct Xcode {
       public unowned var target: Target
     }
   }
-  
+
   /// Abstract base class for all build phases in a target.
   public class BuildPhase {
     public var files: [BuildFile] = []
-    
+
     /// Adds a new build file that refers to `fileRef`.
     @discardableResult
     public func addBuildFile(fileRef: FileReference) -> BuildFile {
@@ -299,25 +396,25 @@ public struct Xcode {
       return buildFile
     }
   }
-  
+
   /// A "headers" build phase, i.e. one that copies headers into a directory
   /// of the product, after suitable processing.
   public final class HeadersBuildPhase: BuildPhase {
     // Nothing extra yet.
   }
-  
+
   /// A "sources" build phase, i.e. one that compiles sources and provides
   /// them to be linked into the executable code of the product.
   public final class SourcesBuildPhase: BuildPhase {
     // Nothing extra yet.
   }
-  
+
   /// A "frameworks" build phase, i.e. one that links compiled code and
   /// libraries into the executable of the product.
   public final class FrameworksBuildPhase: BuildPhase {
     // Nothing extra yet.
   }
-  
+
   /// A "copy files" build phase, i.e. one that copies files to an arbitrary
   /// location relative to the product.
   public final class CopyFilesBuildPhase: BuildPhase {
@@ -326,7 +423,7 @@ public struct Xcode {
       self.dstDir = dstDir
     }
   }
-  
+
   /// A "shell script" build phase, i.e. one that runs a custom shell script.
   public final class ShellScriptBuildPhase: BuildPhase {
     public var script: String
@@ -340,7 +437,7 @@ public struct Xcode {
       self.alwaysRun = alwaysRun
     }
   }
-  
+
   /// A build file, representing the membership of a file reference in a
   /// build phase of a target.
   public final class BuildFile {
@@ -348,19 +445,19 @@ public struct Xcode {
     init(fileRef: FileReference) {
       self.fileRef = fileRef
     }
-    
+
     public var settings = Settings()
-    
+
     /// A set of file settings.
     public struct Settings: Encodable {
       public var ATTRIBUTES: [String]?
       public var COMPILER_FLAGS: String?
-      
+
       public init() {
       }
     }
   }
-  
+
   /// A table of build settings, which for the sake of simplicity consists
   /// (in this simplified model) of a set of common settings, and a set of
   /// overlay settings for Debug and Release builds.  There can also be a
@@ -369,21 +466,21 @@ public struct Xcode {
     /// Common build settings are in both generated configurations (Debug
     /// and Release).
     public var common = BuildSettings()
-    
+
     /// Debug build settings are overlaid over the common settings in the
     /// generated Debug configuration.
     public var debug = BuildSettings()
-    
+
     /// Release build settings are overlaid over the common settings in the
     /// generated Release configuration.
     public var release = BuildSettings()
-    
+
     /// An optional file reference to an .xcconfig file.
     public var xcconfigFileRef: FileReference?
-    
+
     public init() {
     }
-    
+
     /// A set of build settings, which is represented as a struct of optional
     /// build settings.  This is not optimally efficient, but it is great for
     /// code completion and type-checking.
@@ -451,3 +548,39 @@ public struct Xcode {
     }
   }
 }
+
+extension Xcode.BuildableFolder {
+  /// A "target exception" for a buildable folder stores information about
+  /// source files in the folder that are augmented in some way for a given
+  /// target.
+  public final class TargetException {
+    unowned let target: Xcode.Target
+
+    /// The sources that are either excluded from the buildable folder
+    /// (for a primary exception), or are members of another target.
+    fileprivate(set) var sources: [RelativePath] = []
+
+    /// A set of extra compiler arguments for a given source.
+    fileprivate(set) var extraCompilerArgs: [RelativePath: [String]] = [:]
+
+    init(for target: Xcode.Target) {
+      self.target = target
+    }
+  }
+
+  struct FileInTarget: Hashable {
+    var path: RelativePath
+    var target: Xcode.Target
+  }
+}
+
+extension Xcode.Target: Hashable {
+  public static func == (lhs: Xcode.Target, rhs: Xcode.Target) -> Bool {
+    // Identity is a key part of Target, so there's no useful value comparison
+    // to do.
+    lhs === rhs
+  }
+  public func hash(into hasher: inout Hasher) {
+    hasher.combine(ObjectIdentifier(self))
+  }
+}
diff --git a/utils/swift-xcodegen/Sources/Xcodeproj/XcodeProjectModelSerialization.swift b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/XcodeProjectModelSerialization.swift
similarity index 82%
rename from utils/swift-xcodegen/Sources/Xcodeproj/XcodeProjectModelSerialization.swift
rename to utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/XcodeProjectModelSerialization.swift
index 7758dc950dee4..1d24029356a37 100644
--- a/utils/swift-xcodegen/Sources/Xcodeproj/XcodeProjectModelSerialization.swift
+++ b/utils/swift-xcodegen/Sources/SwiftXcodeGen/Xcodeproj/XcodeProjectModelSerialization.swift
@@ -43,6 +43,7 @@ extension Xcode.Project {
 }
 
 extension Xcode.Project: PropertyListSerializable {
+  fileprivate var xcodeClassName: String { "PBXProject" }
 
   /// Generates and returns the contents of a `project.pbxproj` plist.  Does
   /// not generate any ancillary files, such as a set of schemes.
@@ -77,7 +78,7 @@ extension Xcode.Project: PropertyListSerializable {
     // by Xcode when it opens the project and notices that they are missing.
     // Note: we also skip schemes, since they are not in the project plist.
     var dict = [String: PropertyList]()
-    dict["isa"] = .string("PBXProject")
+    dict["isa"] = .string(xcodeClassName)
     // Since the project file is generated, we opt out of upgrade-checking.
     // FIXME: Should we really?  Why would we not want to get upgraded?
     dict["attributes"] = .dictionary(["LastUpgradeCheck": .string("9999"),
@@ -107,27 +108,65 @@ extension Xcode.Project: PropertyListSerializable {
   }
 }
 
+extension Xcode.BuildableFolder.TargetException: PropertyListSerializable {
+  var xcodeClassName: String { "PBXFileSystemSynchronizedBuildFileExceptionSet" }
+
+  fileprivate func serialize(
+    to serializer: PropertyListSerializer
+  ) throws -> [String: PropertyList] {
+    var dict = [String: PropertyList]()
+    dict["isa"] = .string(xcodeClassName)
+    dict["additionalCompilerFlagsByRelativePath"] = .dictionary(
+      Dictionary(
+        uniqueKeysWithValues:
+          extraCompilerArgs.map {
+            ($0.rawPath, PropertyList.string($1.joined(separator: " ")))
+          }
+      )
+    )
+    dict["membershipExceptions"] = .array(sources.map { .string($0.rawPath) })
+    dict["target"] = .identifier(serializer.id(of: target))
+    return dict
+  }
+}
+
 extension Xcode.Reference: PropertyListSerializable {
-  fileprivate dynamic func serialize(
+  fileprivate var xcodeClassName: String {
+    switch self {
+    case is Xcode.Group:
+      "PBXGroup"
+    case let fileRef as Xcode.FileReference:
+      fileRef.isBuildableFolder ? "PBXFileSystemSynchronizedRootGroup"
+                                : "PBXFileReference"
+    default:
+      fatalError("Unhandled subclass")
+    }
+  }
+
+  fileprivate func serialize(
     to serializer: PropertyListSerializer
   ) throws -> [String : PropertyList] {
     var dict = [String: PropertyList]()
+    dict["isa"] = .string(xcodeClassName)
     dict["path"] = .string(path)
     if let name = name {
       dict["name"] = .string(name)
     }
     dict["sourceTree"] = .string(pathBase.rawValue)
 
-    let xcodeClassName: String
     switch self {
     case let group as Xcode.Group:
-      xcodeClassName = "PBXGroup"
       dict["children"] = try .array(group.subitems.map({ reference in
         try .identifier(serializer.serialize(object: reference))
       }))
     case let fileRef as Xcode.FileReference:
-      xcodeClassName = fileRef.isBuildableFolder 
-        ? "PBXFileSystemSynchronizedRootGroup" : "PBXFileReference"
+      if let buildableFolder = fileRef.buildableFolder {
+        dict["exceptions"] = try .array(
+          buildableFolder.makeTargetExceptions().map {
+            try .identifier(serializer.serialize(object: $0))
+          }
+        )
+      }
       if let fileType = fileRef.fileType {
         dict["explicitFileType"] = .string(fileType)
       }
@@ -138,19 +177,21 @@ extension Xcode.Reference: PropertyListSerializable {
     default:
       fatalError("Unhandled subclass")
     }
-    dict["isa"] = .string(xcodeClassName)
     return dict
   }
 }
 
 extension Xcode.Target: PropertyListSerializable {
+  fileprivate var xcodeClassName: String {
+    productType == nil ? "PBXAggregateTarget" : "PBXNativeTarget"
+  }
 
   /// Called by the Serializer to serialize the Target.
   fileprivate func serialize(to serializer: PropertyListSerializer) throws -> [String: PropertyList] {
     // Create either a `PBXNativeTarget` or an `PBXAggregateTarget` plist
     // dictionary (depending on whether or not we have a product type).
     var dict = [String: PropertyList]()
-    dict["isa"] = .string(productType == nil ? "PBXAggregateTarget" : "PBXNativeTarget")
+    dict["isa"] = .string(xcodeClassName)
     dict["name"] = .string(name)
     // Build settings are a bit tricky; in Xcode, each is stored in a named
     // XCBuildConfiguration object, and the list of build configurations is
@@ -169,6 +210,8 @@ extension Xcode.Target: PropertyListSerializable {
     /// glue between our value-based settings structures and the Xcode
     /// project model's identity-based TargetDependency objects.
     class TargetDependency: PropertyListSerializable {
+      var xcodeClassName: String { "PBXTargetDependency" }
+
       var target: Xcode.Target
       init(target: Xcode.Target) {
         self.target = target
@@ -176,7 +219,7 @@ extension Xcode.Target: PropertyListSerializable {
       func serialize(to serializer: PropertyListSerializer) -> [String: PropertyList] {
         // Create a `PBXTargetDependency` plist dictionary.
         var dict = [String: PropertyList]()
-        dict["isa"] = .string("PBXTargetDependency")
+        dict["isa"] = .string(xcodeClassName)
         dict["target"] = .identifier(serializer.id(of: target))
         return dict
       }
@@ -188,7 +231,7 @@ extension Xcode.Target: PropertyListSerializable {
     }))
     if !buildableFolders.isEmpty {
       dict["fileSystemSynchronizedGroups"] = .array(
-        buildableFolders.map { .identifier(serializer.id(of: $0)) }
+        buildableFolders.map { .identifier(serializer.id(of: $0.ref)) }
       )
     }
     dict["productName"] = .string(productName)
@@ -202,73 +245,47 @@ extension Xcode.Target: PropertyListSerializable {
   }
 }
 
-/// Private helper function that constructs and returns a partial property list
-/// dictionary for build phases.  The caller can add to the returned dictionary.
-/// FIXME:  It would be nicer to be able to use inheritance to serialize the
-/// attributes inherited from BuildPhase, but but in Swift 3.0 we get an error
-/// that "declarations in extensions cannot override yet".
-fileprivate func makeBuildPhaseDict(
-  buildPhase: Xcode.BuildPhase,
-  serializer: PropertyListSerializer,
-  xcodeClassName: String
-) throws -> [String: PropertyList] {
-  var dict = [String: PropertyList]()
-  dict["isa"] = .string(xcodeClassName)
-  dict["files"] = try .array(buildPhase.files.map({ file in
-    try .identifier(serializer.serialize(object: file))
-  }))
-  return dict
+extension PropertyListSerializable where Self: Xcode.BuildPhase {
+  /// Helper function that constructs and returns the base property list
+  /// dictionary for build phases.
+  fileprivate func makeBuildPhaseDict(
+    serializer: PropertyListSerializer
+  ) throws -> [String: PropertyList] {
+    var dict = [String: PropertyList]()
+    dict["isa"] = .string(xcodeClassName)
+    dict["files"] = try .array(files.map({ file in
+      try .identifier(serializer.serialize(object: file))
+    }))
+    return dict
+  }
+
+  /// Default serialization implementation.
+  fileprivate func serialize(
+    to serializer: PropertyListSerializer
+  ) throws -> [String: PropertyList] {
+    try makeBuildPhaseDict(serializer: serializer)
+  }
 }
 
 extension Xcode.HeadersBuildPhase: PropertyListSerializable {
-
-  /// Called by the Serializer to serialize the HeadersBuildPhase.
-  fileprivate func serialize(to serializer: PropertyListSerializer) throws -> [String: PropertyList] {
-    // Create a `PBXHeadersBuildPhase` plist dictionary.
-    // FIXME:  It would be nicer to be able to use inheritance for the code
-    // inherited from BuildPhase, but but in Swift 3.0 we get an error that
-    // "declarations in extensions cannot override yet".
-    return try makeBuildPhaseDict(buildPhase: self, serializer: serializer, xcodeClassName: "PBXHeadersBuildPhase")
-  }
+  fileprivate var xcodeClassName: String { "PBXHeadersBuildPhase" }
 }
 
 extension Xcode.SourcesBuildPhase: PropertyListSerializable {
-
-  /// Called by the Serializer to serialize the SourcesBuildPhase.
-  fileprivate func serialize(to serializer: PropertyListSerializer) throws -> [String: PropertyList] {
-    // Create a `PBXSourcesBuildPhase` plist dictionary.
-    // FIXME:  It would be nicer to be able to use inheritance for the code
-    // inherited from BuildPhase, but but in Swift 3.0 we get an error that
-    // "declarations in extensions cannot override yet".
-    return try makeBuildPhaseDict(buildPhase: self, serializer: serializer, xcodeClassName: "PBXSourcesBuildPhase")
-  }
+  fileprivate var xcodeClassName: String { "PBXSourcesBuildPhase" }
 }
 
 extension Xcode.FrameworksBuildPhase: PropertyListSerializable {
-
-  /// Called by the Serializer to serialize the FrameworksBuildPhase.
-  fileprivate func serialize(to serializer: PropertyListSerializer) throws -> [String: PropertyList] {
-    // Create a `PBXFrameworksBuildPhase` plist dictionary.
-    // FIXME:  It would be nicer to be able to use inheritance for the code
-    // inherited from BuildPhase, but but in Swift 3.0 we get an error that
-    // "declarations in extensions cannot override yet".
-    return try makeBuildPhaseDict(buildPhase: self, serializer: serializer, xcodeClassName: "PBXFrameworksBuildPhase")
-  }
+  fileprivate var xcodeClassName: String { "PBXFrameworksBuildPhase" }
 }
 
 extension Xcode.CopyFilesBuildPhase: PropertyListSerializable {
+  fileprivate var xcodeClassName: String { "PBXCopyFilesBuildPhase" }
 
-  /// Called by the Serializer to serialize the FrameworksBuildPhase.
-  fileprivate func serialize(to serializer: PropertyListSerializer) throws -> [String: PropertyList] {
-    // Create a `PBXCopyFilesBuildPhase` plist dictionary.
-    // FIXME:  It would be nicer to be able to use inheritance for the code
-    // inherited from BuildPhase, but but in Swift 3.0 we get an error that
-    // "declarations in extensions cannot override yet".
-    var dict = try makeBuildPhaseDict(
-      buildPhase: self,
-      serializer: serializer,
-      xcodeClassName: "PBXCopyFilesBuildPhase"
-    )
+  fileprivate func serialize(
+    to serializer: PropertyListSerializer
+  ) throws -> [String: PropertyList] {
+    var dict = try makeBuildPhaseDict(serializer: serializer)
     dict["dstPath"] = .string("")   // FIXME: needs to be real
     dict["dstSubfolderSpec"] = .string("")   // FIXME: needs to be real
     return dict
@@ -276,17 +293,12 @@ extension Xcode.CopyFilesBuildPhase: PropertyListSerializable {
 }
 
 extension Xcode.ShellScriptBuildPhase: PropertyListSerializable {
+  fileprivate var xcodeClassName: String { "PBXShellScriptBuildPhase" }
 
-  /// Called by the Serializer to serialize the ShellScriptBuildPhase.
-  fileprivate func serialize(to serializer: PropertyListSerializer) throws -> [String: PropertyList] {
-    // Create a `PBXShellScriptBuildPhase` plist dictionary.
-    // FIXME:  It would be nicer to be able to use inheritance for the code
-    // inherited from BuildPhase, but but in Swift 3.0 we get an error that
-    // "declarations in extensions cannot override yet".
-    var dict = try makeBuildPhaseDict(
-      buildPhase: self,
-      serializer: serializer,
-      xcodeClassName: "PBXShellScriptBuildPhase")
+  fileprivate func serialize(
+    to serializer: PropertyListSerializer
+  ) throws -> [String: PropertyList] {
+    var dict = try makeBuildPhaseDict(serializer: serializer)
     dict["shellPath"] = .string("/bin/sh")   // FIXME: should be settable
     dict["shellScript"] = .string(script)
     dict["inputPaths"] = .array(inputs.map { .string($0) })
@@ -297,12 +309,13 @@ extension Xcode.ShellScriptBuildPhase: PropertyListSerializable {
 }
 
 extension Xcode.BuildFile: PropertyListSerializable {
+  fileprivate var xcodeClassName: String { "PBXBuildFile" }
 
   /// Called by the Serializer to serialize the BuildFile.
   fileprivate func serialize(to serializer: PropertyListSerializer) throws -> [String: PropertyList] {
     // Create a `PBXBuildFile` plist dictionary.
     var dict = [String: PropertyList]()
-    dict["isa"] = .string("PBXBuildFile")
+    dict["isa"] = .string(xcodeClassName)
     if let fileRef = fileRef {
       dict["fileRef"] = .identifier(serializer.id(of: fileRef))
     }
@@ -317,6 +330,7 @@ extension Xcode.BuildFile: PropertyListSerializable {
 }
 
 extension Xcode.BuildSettingsTable: PropertyListSerializable {
+  fileprivate var xcodeClassName: String { "XCConfigurationList" }
 
   /// Called by the Serializer to serialize the BuildFile.  It is serialized
   /// as an XCBuildConfigurationList and two additional XCBuildConfiguration
@@ -331,6 +345,8 @@ extension Xcode.BuildSettingsTable: PropertyListSerializable {
       var overlaySettings: BuildSettings
       let xcconfigFileRef: Xcode.FileReference?
 
+      var xcodeClassName: String { "XCBuildConfiguration" }
+
       init(
         name: String,
         baseSettings: BuildSettings,
@@ -346,7 +362,7 @@ extension Xcode.BuildSettingsTable: PropertyListSerializable {
       func serialize(to serializer: PropertyListSerializer) throws -> [String: PropertyList] {
         // Create a `XCBuildConfiguration` plist dictionary.
         var dict = [String: PropertyList]()
-        dict["isa"] = .string("XCBuildConfiguration")
+        dict["isa"] = .string(xcodeClassName)
         dict["name"] = .string(name)
         // Combine the base settings and the overlay settings.
         dict["buildSettings"] = try combineBuildSettingsPropertyLists(
@@ -363,7 +379,7 @@ extension Xcode.BuildSettingsTable: PropertyListSerializable {
 
     // Create a `XCConfigurationList` plist dictionary.
     var dict = [String: PropertyList]()
-    dict["isa"] = .string("XCConfigurationList")
+    dict["isa"] = .string(xcodeClassName)
     dict["buildConfigurations"] = .array([
       // We use a private wrapper to "objectify" our two build settings
       // structures (which, being structs, are value types).
@@ -386,6 +402,14 @@ extension Xcode.BuildSettingsTable: PropertyListSerializable {
   }
 }
 
+fileprivate struct InternalError: Error {
+  private let description: String
+  public init(_ description: String) {
+    assertionFailure(description)
+    self.description = description
+  }
+}
+
 /// Private helper function that combines a base property list and an overlay
 /// property list, respecting the semantics of `$(inherited)` as we go.
 fileprivate func combineBuildSettingsPropertyLists(
@@ -527,6 +551,9 @@ fileprivate protocol PropertyListSerializable: AnyObject {
   /// matters.  So this is acceptable for now in the interest of getting it
   /// done.
 
+  /// The ID for the `isa` field of the object.
+  var xcodeClassName: String { get }
+
   /// A custom ID to use for the instance, if enabled.
   ///
   /// This ID must be unique across the entire serialized graph.
diff --git a/utils/swift-xcodegen/Sources/Xcodeproj/Errors.swift b/utils/swift-xcodegen/Sources/Xcodeproj/Errors.swift
deleted file mode 100644
index ceba751ea8862..0000000000000
--- a/utils/swift-xcodegen/Sources/Xcodeproj/Errors.swift
+++ /dev/null
@@ -1,19 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift open source project
-//
-// Copyright (c) 2024 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See http://swift.org/LICENSE.txt for license information
-// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-public struct InternalError: Error {
-  private let description: String
-  public init(_ description: String) {
-    assertionFailure(description)
-    self.description = description
-  }
-}
diff --git a/utils/swift-xcodegen/Sources/swift-xcodegen/Options.swift b/utils/swift-xcodegen/Sources/swift-xcodegen/Options.swift
index b368c5e32e1fc..8ea3882a581c7 100644
--- a/utils/swift-xcodegen/Sources/swift-xcodegen/Options.swift
+++ b/utils/swift-xcodegen/Sources/swift-xcodegen/Options.swift
@@ -214,10 +214,6 @@ struct ProjectOptions: ParsableArguments {
       folder references to be used for compatible targets. This allows new
       source files to be added to a target without needing to regenerate the
       project.
-      
-      Only supported for targets that have no per-file build settings. This
-      unfortunately means some Clang targes such as 'lib/Basic' and 'stdlib' 
-      cannot currently use buildable folders.
       """
   )
   var useBuildableFolders: Bool = true
@@ -246,10 +242,13 @@ struct MiscOptions: ParsableArguments {
     """)
   var projectRootDir: AnyPath?
 
-  @Option(help: """
-    The output directory to write the Xcode project to. Defaults to the project
-    root directory.
-    """)
+  @Option(
+    name: .shortAndLong,
+    help: """
+      The output directory to write the Xcode project to. Defaults to the
+      project root directory.
+      """
+  )
   var outputDir: AnyPath?
 
   @Option(help: "The log level verbosity (default: info)")
diff --git a/utils/swift-xcodegen/Sources/swift-xcodegen/SwiftXcodegen.swift b/utils/swift-xcodegen/Sources/swift-xcodegen/SwiftXcodegen.swift
index 854dc524c7213..4cddbb98d4656 100644
--- a/utils/swift-xcodegen/Sources/swift-xcodegen/SwiftXcodegen.swift
+++ b/utils/swift-xcodegen/Sources/swift-xcodegen/SwiftXcodegen.swift
@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 import ArgumentParser
-import Darwin
+import Foundation
 import SwiftXcodeGen
 
 @main
@@ -84,7 +84,7 @@ struct SwiftXcodegen: AsyncParsableCommand, Sendable {
 
     // Check to see if we have a separate runnable build dir.
     let runnableBuildDirPath = 
-      self.runnableBuildDir?.absoluteInWorkingDir.resolvingSymlinks
+      self.runnableBuildDir?.absoluteInWorkingDir.realPath
     let runnableBuildDir = try runnableBuildDirPath.map {
       try NinjaBuildDir(at: $0, projectRootDir: ninja.projectRootDir)
         .buildDir(for: .swift)
@@ -204,7 +204,7 @@ struct SwiftXcodegen: AsyncParsableCommand, Sendable {
       if self.addClangToolsExtra {
         spec.addClangTargets(
           below: "../clang-tools-extra", addingPrefix: "extra-",
-          mayHaveUnbuildableFiles: true
+          mayHaveUnbuildableFiles: true, excluding: ["test"]
         )
         if self.addTestFolders {
           spec.addReference(to: "../clang-tools-extra/test")
@@ -332,7 +332,7 @@ struct SwiftXcodegen: AsyncParsableCommand, Sendable {
   }
 
   func generate() async throws {
-    let buildDirPath = buildDir.absoluteInWorkingDir.resolvingSymlinks
+    let buildDirPath = buildDir.absoluteInWorkingDir.realPath
     log.info("Generating project for '\(buildDirPath)'...")
 
     let projectRootDir = self.projectRootDir?.absoluteInWorkingDir
@@ -399,14 +399,37 @@ struct SwiftXcodegen: AsyncParsableCommand, Sendable {
         try lldbLLVMWorkspace.write("LLDB+LLVM", into: outputDir)
       }
     }
-    showCaveatsIfNeeded()
+  }
+
+  func printingTimeTaken<T>(_ fn: () async throws -> T) async rethrows -> T {
+    let start = ContinuousClock.now
+    let result = try await fn()
+    let end = ContinuousClock.now
+
+    let duration = start.duration(to: end)
+
+    // Note we don't print the time taken when we fail.
+    var message = "Successfully generated in "
+    message += duration.formatted(
+      .units(
+        allowed: [.seconds],
+        width: .narrow,
+        fractionalPart: .init(lengthLimits: 0...3, roundingRule: .up)
+      )
+    )
+    log.info(message)
+
+    return result
   }
 
   func run() async {
     // Set the log level
     log.logLevel = .init(self.logLevel ?? (self.quiet ? .warning : .info))
     do {
-      try await generate()
+      try await printingTimeTaken {
+        try await generate()
+      }
+      showCaveatsIfNeeded()
     } catch {
       log.error("\(error)")
     }
diff --git a/utils/swift-xcodegen/Tests/SwiftXcodeGenTest/CompileCommandsTests.swift b/utils/swift-xcodegen/Tests/SwiftXcodeGenTest/CompileCommandsTests.swift
index 79afeba75ca8f..43da93ce66985 100644
--- a/utils/swift-xcodegen/Tests/SwiftXcodeGenTest/CompileCommandsTests.swift
+++ b/utils/swift-xcodegen/Tests/SwiftXcodeGenTest/CompileCommandsTests.swift
@@ -54,6 +54,31 @@ class CompileCommandsTests: XCTestCase {
       knownCommandOnly: true
     )
 
+    for op in ["&&", "||", ">", "<", ">>", ";", "(", ")"] {
+      assertParse(
+        "x y x/y/clang -DX -I \(op) ignored",
+        executable: "x/y/clang",
+        args: [.option(.D, spacing: .unspaced, value: "X"), .flag(.I)],
+        knownCommandOnly: true
+      )
+      assertParse(
+        "x y x/y/clang -DX -I x\(op) ignored",
+        executable: "x/y/clang",
+        args: [
+          .option(.D, spacing: .unspaced, value: "X"),
+          .option(.I, spacing: .spaced, value: "x")
+        ],
+        knownCommandOnly: true
+      )
+    }
+
+    assertParse(
+      #"x/y/clang \< x\< "<""#,
+      executable: "x/y/clang",
+      args: [.value("<"), .value("x<"), .value("<")],
+      knownCommandOnly: true
+    )
+
     assertParse(
       "clang -DX -I", 
       args: [.option(.D, spacing: .unspaced, value: "X"), .flag(.I)]
diff --git a/utils/swift-xcodegen/Tests/SwiftXcodeGenTest/PathTests.swift b/utils/swift-xcodegen/Tests/SwiftXcodeGenTest/PathTests.swift
index 5ad40c301c766..a77c027585a0e 100644
--- a/utils/swift-xcodegen/Tests/SwiftXcodeGenTest/PathTests.swift
+++ b/utils/swift-xcodegen/Tests/SwiftXcodeGenTest/PathTests.swift
@@ -37,4 +37,28 @@ class PathTests: XCTestCase {
     XCTAssertEqual(RelativePath("foo/bar").dropLast(2), "")
     XCTAssertEqual(RelativePath("foo/bar").dropLast(5), "")
   }
+
+  func testExtension() throws {
+    func match(
+      _ ext: FileExtension, with path: String,
+      value: Bool = true, file: StaticString = #file, line: UInt = #line
+    ) {
+      XCTAssert(path.hasExtension(ext) == value, file: file, line: line)
+      XCTAssert(AnyPath(path).hasExtension(ext) == value, file: file, line: line)
+    }
+    match(.swift, with: "x.swift")
+    match(.swift, with: "/x.swift")
+    match(.swift, with: ".swift", value: false)
+    match(.swift, with: "/.swift", value: false)
+
+    match(.swift, with: "x.SWIFT")
+    match(.swift, with: "/x.SWIFT")
+    match(.swift, with: ".SWIFT", value: false)
+    match(.swift, with: "/.SWIFT", value: false)
+
+    match(.swift, with: "x.swiftx", value: false)
+
+    XCTAssert("x.sWift".hasExtension(.asm, .swift))
+    XCTAssert(AnyPath("x.sWift").hasExtension(.asm, .swift))
+  }
 }
diff --git a/utils/swift_build_support/swift_build_support/build_script_invocation.py b/utils/swift_build_support/swift_build_support/build_script_invocation.py
index 8a70921d1569e..f52bf2237ef70 100644
--- a/utils/swift_build_support/swift_build_support/build_script_invocation.py
+++ b/utils/swift_build_support/swift_build_support/build_script_invocation.py
@@ -108,6 +108,8 @@ def convert_to_impl_arguments(self):
             "--swift-enable-assertions", str(args.swift_assertions).lower(),
             "--swift-stdlib-enable-assertions", str(
                 args.swift_stdlib_assertions).lower(),
+            "--swift-stdlib-enable-strict-availability", str(
+                args.swift_stdlib_strict_availability).lower(),
             "--swift-analyze-code-coverage", str(
                 args.swift_analyze_code_coverage).lower(),
             "--llbuild-enable-assertions", str(
@@ -117,6 +119,8 @@ def convert_to_impl_arguments(self):
             "--cmake-generator", args.cmake_generator,
             "--cross-compile-append-host-target-to-destdir", str(
                 args.cross_compile_append_host_target_to_destdir).lower(),
+            "--cross-compile-build-swift-tools", str(
+                args.cross_compile_build_swift_tools).lower(),
             "--build-jobs", str(args.build_jobs),
             "--lit-jobs", str(args.lit_jobs),
             "--common-cmake-options=%s" % ' '.join(
@@ -621,7 +625,7 @@ def compute_product_pipelines(self):
         # Swift still needs a few LLVM targets like tblgen to be built for it to be
         # configured. Instead, handle this in the product for now.
         builder.add_product(products.LLVM,
-                            is_enabled=True)
+                            is_enabled=self.args.build_llvm or self.args.build_swift or self.args.build_lldb)
 
         builder.add_product(products.StaticSwiftLinuxConfig,
                             is_enabled=self.args.install_static_linux_config)
@@ -670,23 +674,25 @@ def compute_product_pipelines(self):
                             is_enabled=self.args.build_wasmstdlib)
         builder.add_product(products.WasmLLVMRuntimeLibs,
                             is_enabled=self.args.build_wasmstdlib)
-        builder.add_product(products.WasmThreadsLLVMRuntimeLibs,
-                            is_enabled=self.args.build_wasmstdlib)
+
+        builder.add_product(products.SwiftTestingMacros,
+                            is_enabled=self.args.build_swift_testing_macros)
+        builder.add_product(products.SwiftTesting,
+                            is_enabled=self.args.build_swift_testing)
+        builder.add_product(products.SwiftPM,
+                            is_enabled=self.args.build_swiftpm)
+
         builder.add_product(products.WasmKit,
                             is_enabled=self.args.build_wasmkit)
         builder.add_product(products.WasmStdlib,
-                            is_enabled=self.args.build_wasmstdlib)
+                            # Revert `or self.args.test_wasmstdlib` once we adopt `wasi-sdk-26`
+                            # or higher version that includes https://github.com/WebAssembly/wasi-libc/commit/eadb436d5c09f7983c3a687086e5af6b6e9f5510.patch
+                            is_enabled=self.args.build_wasmstdlib or self.args.test_wasmstdlib)
         builder.add_product(products.WasmThreadsStdlib,
                             is_enabled=self.args.build_wasmstdlib)
         builder.add_product(products.WasmSwiftSDK,
                             is_enabled=self.args.build_wasmstdlib)
 
-        builder.add_product(products.SwiftTestingMacros,
-                            is_enabled=self.args.build_swift_testing_macros)
-        builder.add_product(products.SwiftTesting,
-                            is_enabled=self.args.build_swift_testing)
-        builder.add_product(products.SwiftPM,
-                            is_enabled=self.args.build_swiftpm)
         builder.add_product(products.SwiftFoundationTests,
                             is_enabled=self.args.build_foundation)
         builder.add_product(products.FoundationTests,
diff --git a/utils/swift_build_support/swift_build_support/cmake.py b/utils/swift_build_support/swift_build_support/cmake.py
index 8cafcf5353b64..9a0f5b43e2d7e 100644
--- a/utils/swift_build_support/swift_build_support/cmake.py
+++ b/utils/swift_build_support/swift_build_support/cmake.py
@@ -150,13 +150,15 @@ def common_options(self, product=None):
             define("CMAKE_CXX_COMPILER_LAUNCHER:PATH", args.cmake_cxx_launcher)
 
         if self.prefer_native_toolchain and product:
+            clang_tools_path = product.native_clang_tools_path(args.host_target)
+            define("CMAKE_C_COMPILER:PATH", os.path.join(clang_tools_path,
+                                                         'bin', 'clang'))
+            define("CMAKE_CXX_COMPILER:PATH", os.path.join(clang_tools_path,
+                                                           'bin', 'clang++'))
+
             toolchain_path = product.native_toolchain_path(args.host_target)
             cmake_swiftc_path = os.getenv('CMAKE_Swift_COMPILER',
                                           os.path.join(toolchain_path, 'bin', 'swiftc'))
-            define("CMAKE_C_COMPILER:PATH", os.path.join(toolchain_path,
-                                                         'bin', 'clang'))
-            define("CMAKE_CXX_COMPILER:PATH", os.path.join(toolchain_path,
-                                                           'bin', 'clang++'))
             define("CMAKE_Swift_COMPILER:PATH", cmake_swiftc_path)
         else:
             cmake_swiftc_path = os.getenv('CMAKE_Swift_COMPILER', toolchain.swiftc)
@@ -282,14 +284,9 @@ def build_cmake(self, source_root, build_root):
         os.chdir(cwd)
         return os.path.join(cmake_build_dir, 'bin', 'cmake')
 
-    # Get the path to CMake to use for the build
-    # This function will not build CMake for Apple platforms.
-    # For other platforms, this builds CMake if a new enough version is not
-    # available.
+    # Get the path to CMake to use for the build, this builds CMake if a new enough
+    # version is not available.
     def get_cmake_path(self, source_root, build_root):
-        if platform.system() == 'Darwin':
-            return self.toolchain.cmake
-
         cmake_source_dir = os.path.join(source_root, 'cmake')
         if not os.path.isdir(cmake_source_dir):
             return self.toolchain.cmake
diff --git a/utils/swift_build_support/swift_build_support/host_specific_configuration.py b/utils/swift_build_support/swift_build_support/host_specific_configuration.py
index 5d37027ce0c5c..28988757a44ed 100644
--- a/utils/swift_build_support/swift_build_support/host_specific_configuration.py
+++ b/utils/swift_build_support/swift_build_support/host_specific_configuration.py
@@ -215,6 +215,11 @@ def __init__(self, host_target, args, stage_dependent_args=None):
                     self.swift_test_run_targets.append(
                         "check-swift{}-optimize_none_with_implicit_dynamic-{}"
                         .format(subset_suffix, name))
+                if args.test_optimize_none_with_opaque_values and \
+                        not test_host_only:
+                    self.swift_test_run_targets.append(
+                        "check-swift{}-optimize_none_with_opaque_values-{}"
+                        .format(subset_suffix, name))
 
             # Only pull in these flags when cross-compiling with
             # --cross-compile-hosts.
diff --git a/utils/swift_build_support/swift_build_support/productpipeline_list_builder.py b/utils/swift_build_support/swift_build_support/productpipeline_list_builder.py
index 056e8af2f117f..3894c85620b7c 100644
--- a/utils/swift_build_support/swift_build_support/productpipeline_list_builder.py
+++ b/utils/swift_build_support/swift_build_support/productpipeline_list_builder.py
@@ -2,7 +2,7 @@
 #
 # This source file is part of the Swift.org open source project
 #
-# Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+# Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
 # See https:#swift.org/LICENSE.txt for license information
@@ -91,7 +91,7 @@ def reset(self):
         self.current_count = 0
         self.current_pipeline = None
         self.is_current_pipeline_impl = False
-        self.pipelinst_list = []
+        self.pipeline_list = []
 
     def add_product(self, product_cls, is_enabled):
         """Add a non-impl product to the current pipeline begin constructed"""
@@ -182,7 +182,7 @@ def infer(self):
         return (filtered_results, last_impl_pipeline_index)
 
     def finalize(self, shouldInfer):
-        """Product a final schedule and return a list of our product pipelines. Resets
+        """Produce a final schedule and return a list of our product pipelines. Resets
            the builder when done so is a consuming operation.
         """
         # Append the current pipeline if we have one.
diff --git a/utils/swift_build_support/swift_build_support/products/__init__.py b/utils/swift_build_support/swift_build_support/products/__init__.py
index d9ab581c7ec1b..c577cf0884641 100644
--- a/utils/swift_build_support/swift_build_support/products/__init__.py
+++ b/utils/swift_build_support/swift_build_support/products/__init__.py
@@ -42,7 +42,7 @@
 from .swiftpm import SwiftPM
 from .swiftsyntax import SwiftSyntax
 from .tsan_libdispatch import TSanLibDispatch
-from .wasisysroot import WASILibc, WasmLLVMRuntimeLibs, WasmThreadsLLVMRuntimeLibs
+from .wasisysroot import WASILibc, WasmLLVMRuntimeLibs
 from .wasmkit import WasmKit
 from .wasmstdlib import WasmStdlib, WasmThreadsStdlib
 from .wasmswiftsdk import WasmSwiftSDK
@@ -88,7 +88,6 @@
     'WasmLLVMRuntimeLibs',
     'WasmKit',
     'WasmStdlib',
-    'WasmThreadsLLVMRuntimeLibs',
     'WasmThreadsStdlib',
     'WasmSwiftSDK',
 ]
diff --git a/utils/swift_build_support/swift_build_support/products/cmake_product.py b/utils/swift_build_support/swift_build_support/products/cmake_product.py
index dc338334f284d..3713086fec3d5 100644
--- a/utils/swift_build_support/swift_build_support/products/cmake_product.py
+++ b/utils/swift_build_support/swift_build_support/products/cmake_product.py
@@ -24,7 +24,8 @@ def is_verbose(self):
         return self.args.verbose_build
 
     def build_with_cmake(self, build_targets, build_type, build_args,
-                         prefer_native_toolchain=False):
+                         prefer_native_toolchain=False, 
+                         ignore_extra_cmake_options=False, build_llvm=True):
         assert self.toolchain.cmake is not None
         cmake_build = []
         _cmake = cmake.CMake(self.args, self.toolchain,
@@ -67,13 +68,12 @@ def build_with_cmake(self, build_targets, build_type, build_args,
                 shell.call(["env"] + [self.toolchain.cmake]
                            + list(_cmake.common_options(self))
                            + list(self.cmake_options)
-                           + self.args.extra_cmake_options + [self.source_dir],
+                           + (self.args.extra_cmake_options if not ignore_extra_cmake_options else [])
+                           + [self.source_dir],
                            env=env)
 
         is_llvm = self.product_name() == "llvm"
-        if (not is_llvm and not self.args.skip_build) or (
-            is_llvm and self.args._build_llvm
-        ):
+        if (not is_llvm and not self.args.skip_build) or (is_llvm and build_llvm):
             cmake_opts = [self.build_dir, "--config", build_type]
 
             shell.call(
@@ -133,6 +133,7 @@ def host_cmake_options(self, host_target):
 
         llvm_target_arch = None
         cmake_osx_deployment_target = None
+        cmake_os_sysroot = None
         swift_host_triple = None
         swift_host_variant = platform
         swift_host_variant_sdk = platform.upper()
@@ -381,19 +382,6 @@ def host_cmake_options(self, host_target):
             # in the compiler checks CMake performs
             swift_cmake_options.define('CMAKE_OSX_ARCHITECTURES', arch)
 
-        # We don't currently support building compiler-rt for cross-compile targets.
-        # It's not clear that's useful anyway.
-        if self.is_cross_compile_target(host_target):
-            llvm_cmake_options.define('LLVM_TOOL_COMPILER_RT_BUILD:BOOL', 'FALSE')
-            llvm_cmake_options.define('LLVM_BUILD_EXTERNAL_COMPILER_RT:BOOL', 'FALSE')
-        else:
-            llvm_cmake_options.define('LLVM_TOOL_COMPILER_RT_BUILD:BOOL',
-                                      cmake.CMakeOptions.true_false(
-                                          self.args.build_compiler_rt))
-            llvm_cmake_options.define('LLVM_BUILD_EXTERNAL_COMPILER_RT:BOOL',
-                                      cmake.CMakeOptions.true_false(
-                                          self.args.build_compiler_rt))
-
         # If we are asked to not generate test targets for LLVM and or Swift,
         # disable as many LLVM tools as we can. This improves compile time when
         # compiling with LTO.
@@ -428,4 +416,8 @@ def host_cmake_options(self, host_target):
 
         llvm_cmake_options.define('COVERAGE_DB', self.args.coverage_db)
 
-        return (llvm_cmake_options, swift_cmake_options)
+        # This provides easier access to certain settings
+        # users may need without having to use CMakeOptions interface
+        relevant_options = {'CMAKE_OSX_SYSROOT': cmake_os_sysroot}
+
+        return (llvm_cmake_options, swift_cmake_options, relevant_options)
diff --git a/utils/swift_build_support/swift_build_support/products/curl.py b/utils/swift_build_support/swift_build_support/products/curl.py
index 5025f5c8bcdf6..d8c2f32dd8dff 100644
--- a/utils/swift_build_support/swift_build_support/products/curl.py
+++ b/utils/swift_build_support/swift_build_support/products/curl.py
@@ -114,8 +114,8 @@ def build(self, host_target):
         self.cmake_options.define('ENABLE_UNIX_SOCKETS', 'NO')
         self.cmake_options.define('ENABLE_THREADED_RESOLVER', 'NO')
         self.cmake_options.define('USE_ECH', 'NO')
-        self.cmake_options.deifne('USE_HTTPSRR', 'NO')
-        self.cmake_options.deifne('USE_OPENSSL_QUIC', 'NO')
+        self.cmake_options.define('USE_HTTPSRR', 'NO')
+        self.cmake_options.define('USE_OPENSSL_QUIC', 'NO')
 
         self.generate_toolchain_file_for_darwin_or_linux(host_target)
 
@@ -123,4 +123,4 @@ def build(self, host_target):
             # If we're building zlib, make cmake search in the built toolchain
             toolchain_path = self.host_install_destdir(host_target)
             self.cmake_options.define('CMAKE_FIND_ROOT_PATH', toolchain_path)
-        self.build_with_cmake(['libcurl'], self.args.curl_build_variant, [])
+        self.build_with_cmake(['libcurl_static'], self.args.curl_build_variant, [])
diff --git a/utils/swift_build_support/swift_build_support/products/foundationtests.py b/utils/swift_build_support/swift_build_support/products/foundationtests.py
index 1b68a09243733..974db85785e90 100644
--- a/utils/swift_build_support/swift_build_support/products/foundationtests.py
+++ b/utils/swift_build_support/swift_build_support/products/foundationtests.py
@@ -53,7 +53,10 @@ def should_test(self, host_target):
         return self.args.test_foundation
 
     def configuration(self):
-        return 'release' if self.is_release() else 'debug'
+        if self.args.foundation_tests_build_variant in ['Release', 'RelWithDebInfo']:
+            return 'release'
+        else:
+            return 'debug'
 
     def test(self, host_target):
         swift_exec = os.path.join(
diff --git a/utils/swift_build_support/swift_build_support/products/llvm.py b/utils/swift_build_support/swift_build_support/products/llvm.py
index ffae1d6670200..7b484a4b71588 100644
--- a/utils/swift_build_support/swift_build_support/products/llvm.py
+++ b/utils/swift_build_support/swift_build_support/products/llvm.py
@@ -141,7 +141,7 @@ def copy_embedded_compiler_rt_builtins_from_darwin_host_toolchain(
                                                      'lib', 'darwin')
                 print('copying compiler-rt embedded builtins from {}'
                       ' into the local clang build directory {}.'.format(
-                          host_cxx_builtins_dir, dest_builtins_dir))
+                          host_cxx_builtins_dir, dest_builtins_dir), flush=True)
 
                 for _os in ['ios', 'watchos', 'tvos', 'xros']:
                     # Copy over the device .a when necessary
@@ -234,7 +234,7 @@ def build(self, host_target):
 
         (platform, arch) = host_target.split('-')
 
-        llvm_cmake_options = self.host_cmake_options(host_target)[0]
+        llvm_cmake_options, _, relevant_options = self.host_cmake_options(host_target)
         llvm_cmake_options.extend_raw(self.args.llvm_cmake_options)
 
         # TODO: handle cross compilation
@@ -242,17 +242,22 @@ def build(self, host_target):
         llvm_cmake_options.define('INTERNAL_INSTALL_PREFIX', 'local')
 
         if host_target.startswith('linux'):
-            toolchain_file = self.generate_linux_toolchain_file(platform, arch)
+            toolchain_file = self.generate_linux_toolchain_file(
+                platform, arch,
+                crosscompiling=self.is_cross_compile_target(host_target))
             llvm_cmake_options.define('CMAKE_TOOLCHAIN_FILE:PATH', toolchain_file)
             if not self.is_release():
                 # On Linux build LLVM and subprojects with -gsplit-dwarf which is more
                 # space/time efficient than -g on that platform.
                 llvm_cmake_options.define('LLVM_USE_SPLIT_DWARF:BOOL', 'YES')
 
-        if not self.args._build_llvm:
+        build = True
+        if not self.args._build_llvm or (not self.args.cross_compile_build_swift_tools
+                                         and self.is_cross_compile_target(host_target)):
             # Indicating we don't want to build LLVM at all should
             # override everything.
             build_targets = []
+            build = False
         elif self.args.skip_build or not self.args.build_llvm:
             # We can't skip the build completely because the standalone
             # build of Swift depends on these.
@@ -300,18 +305,74 @@ def build(self, host_target):
         llvm_cmake_options.define('LLVM_INCLUDE_DOCS:BOOL', 'TRUE')
         llvm_cmake_options.define('LLVM_ENABLE_LTO:STRING', self.args.lto_type)
         llvm_cmake_options.define('COMPILER_RT_INTERCEPT_LIBDISPATCH', 'ON')
+        # Swift expects the old layout for the runtime directory
+        # updating this in tracked in #80180
+        llvm_cmake_options.define('LLVM_ENABLE_PER_TARGET_RUNTIME_DIR', 'OFF')
+        if host_target.startswith('linux'):
+            # This preserves the behaviour we had when using
+            # LLVM_BUILD_EXTERNAL COMPILER_RT --
+            # that is, having the linker not complaining if symbols used
+            # by TSan are undefined (namely the ones for Blocks Runtime)
+            # In the long term, we want to remove this and
+            # build Blocks Runtime before LLVM
+            if ("-DCLANG_DEFAULT_LINKER=gold" in llvm_cmake_options
+                or "-DCLANG_DEFAULT_LINKER:STRING=gold" in llvm_cmake_options):
+                print("Assuming just built clang will use a gold linker -- "
+                      "if that's not the case, please adjust the value of "
+                      "`SANITIZER_COMMON_LINK_FLAGS` in `extra-llvm-cmake-options`",
+                      flush=True)
+                llvm_cmake_options.define(
+                    'SANITIZER_COMMON_LINK_FLAGS:STRING',
+                    '-Wl,--unresolved-symbols,ignore-in-object-files')
+            else:
+                print("Assuming just built clang will use a non gold linker -- "
+                      "if that's not the case, please adjust the value of "
+                      "`SANITIZER_COMMON_LINK_FLAGS` in `extra-llvm-cmake-options`",
+                      flush=True)
+                llvm_cmake_options.define(
+                    'SANITIZER_COMMON_LINK_FLAGS:STRING', '-Wl,-z,undefs')
+
+        builtins_runtimes_target_for_darwin = f'{arch}-apple-darwin'
+        if system() == "Darwin":
+            llvm_cmake_options.define(
+                f'BUILTINS_{builtins_runtimes_target_for_darwin}_'
+                'CMAKE_OSX_SYSROOT',
+                relevant_options['CMAKE_OSX_SYSROOT'])
+            llvm_cmake_options.define(
+                f'RUNTIMES_{builtins_runtimes_target_for_darwin}_'
+                'CMAKE_OSX_SYSROOT',
+                relevant_options['CMAKE_OSX_SYSROOT'])
+            llvm_cmake_options.define(
+                'LLVM_BUILTIN_TARGETS', builtins_runtimes_target_for_darwin)
+            llvm_cmake_options.define(
+                'LLVM_RUNTIME_TARGETS', builtins_runtimes_target_for_darwin)
+            llvm_cmake_options.define('RUNTIMES_BUILD_ALLOW_DARWIN', 'ON')
+            # Build all except rtsan
+            llvm_cmake_options.define(
+                f'RUNTIMES_{builtins_runtimes_target_for_darwin}_'
+                'COMPILER_RT_SANITIZERS_TO_BUILD',
+                'asan;dfsan;msan;hwasan;tsan;safestack;cfi;scudo_standalone;'
+                'ubsan_minimal;gwp_asan;nsan;asan_abi')
 
         if self.args.build_embedded_stdlib and system() == "Darwin":
             # Ask for Mach-O cross-compilation builtins (for Embedded Swift)
             llvm_cmake_options.define(
-                'COMPILER_RT_FORCE_BUILD_BAREMETAL_MACHO_BUILTINS_ARCHS:STRING',
-                'armv6 armv6m armv7 armv7m armv7em')
+                f'BUILTINS_{builtins_runtimes_target_for_darwin}_'
+                'COMPILER_RT_FORCE_BUILD_BAREMETAL_MACHO_BUILTINS_ARCHS:'
+                'STRING', 'armv6 armv6m armv7 armv7m armv7em')
 
         llvm_enable_projects = ['clang']
+        llvm_enable_runtimes = []
 
         if self.args.build_compiler_rt and \
                 not self.is_cross_compile_target(host_target):
-            llvm_enable_projects.append('compiler-rt')
+            llvm_enable_runtimes.append('compiler-rt')
+
+        # This accounts for previous incremental runs using the old
+        # way of build compiler_rt that may have set
+        # those in the LLVM CMakeCache.txt
+        llvm_cmake_options.undefine('LLVM_TOOL_COMPILER_RT_BUILD')
+        llvm_cmake_options.undefine('LLVM_BUILD_EXTERNAL_COMPILER_RT')
 
         if self.args.build_clang_tools_extra:
             llvm_enable_projects.append('clang-tools-extra')
@@ -327,16 +388,8 @@ def build(self, host_target):
 
         llvm_cmake_options.define('LLVM_ENABLE_PROJECTS',
                                   ';'.join(llvm_enable_projects))
-
-        # In the near future we are aiming to build compiler-rt with
-        # LLVM_ENABLE_RUNTIMES
-        # Until that happens, we need to unset this variable from
-        # LLVM CMakeCache.txt for two reasons
-        # * prevent PRs testing this variable to affect other runs landing
-        #   unrelated features
-        # * avoid fallouts should we land such change and then have to revert
-        #   it to account for unforeseen regressions
-        llvm_cmake_options.undefine('LLVM_ENABLE_RUNTIMES')
+        llvm_cmake_options.define('LLVM_ENABLE_RUNTIMES',
+                                  ';'.join(llvm_enable_runtimes))
 
         # NOTE: This is not a dead option! It is relied upon for certain
         # bots/build-configs!
@@ -369,6 +422,12 @@ def build(self, host_target):
             llvm_cmake_options.define('LLVM_INCLUDE_TESTS', 'NO')
             llvm_cmake_options.define('CLANG_INCLUDE_TESTS', 'NO')
 
+        if ("-DLLVM_INCLUDE_TESTS=NO" not in llvm_cmake_options
+            and "-DLLVM_INCLUDE_TESTS:BOOL=FALSE" not in llvm_cmake_options):
+            # This supports scenarios where tests are run
+            # outside of `build-script` (e.g. with `run-test`)
+            build_targets.append('LLVMTestingSupport')
+
         build_root = os.path.dirname(self.build_dir)
         host_machine_target = targets.StdlibDeploymentTarget.host_target().name
         host_build_dir = os.path.join(build_root, 'llvm-{}'.format(
@@ -387,8 +446,6 @@ def build(self, host_target):
                                                 'clang-tidy-confusable-chars-gen')
             llvm_cmake_options.define('CLANG_TIDY_CONFUSABLE_CHARS_GEN',
                                       confusable_chars_gen)
-            pseudo_gen = os.path.join(host_build_dir, 'bin', 'clang-pseudo-gen')
-            llvm_cmake_options.define('CLANG_PSEUDO_GEN', pseudo_gen)
             llvm = os.path.join(host_build_dir, 'llvm')
             llvm_cmake_options.define('LLVM_NATIVE_BUILD', llvm)
 
@@ -396,10 +453,12 @@ def build(self, host_target):
 
         self.cmake_options.extend(host_config.cmake_options)
         self.cmake_options.extend(llvm_cmake_options)
+        self.cmake_options.extend_raw(self.args.extra_llvm_cmake_options)
 
         self._handle_cxx_headers(host_target, platform)
 
-        self.build_with_cmake(build_targets, self.args.llvm_build_variant, [])
+        self.build_with_cmake(build_targets, self.args.llvm_build_variant, [],
+                              build_llvm=build)
 
         # copy over the compiler-rt builtins for iOS/tvOS/watchOS to ensure
         # that Swift's stdlib can use compiler-rt builtins when targeting
@@ -484,7 +543,9 @@ def should_install(self, host_target):
         Whether or not this product should be installed with the given
         arguments.
         """
-        return self.args.install_llvm
+        return self.args.install_llvm and (
+            self.args.cross_compile_build_swift_tools or
+            not self.is_cross_compile_target(host_target))
 
     def install(self, host_target):
         """
@@ -500,9 +561,20 @@ def install(self, host_target):
            self.args.llvm_install_components != 'all':
             install_targets = []
             components = self.args.llvm_install_components.split(';')
+            if 'compiler-rt' in components:
+                # This is a courtesy fallback to avoid breaking downstream presets
+                # that are still using the old compiler-rt install component
+                components.remove('compiler-rt')
+                components.append('builtins')
+                components.append('runtimes')
+                print('warning: replaced legacy LLVM component compiler-rt '
+                      'with builtins;runtimes -- consider updating your preset',
+                      flush=True)
+
             for component in components:
-                if self.is_cross_compile_target(host_target):
-                    if component == 'compiler-rt':
+                if self.is_cross_compile_target(host_target) \
+                   or not self.args.build_compiler_rt:
+                    if component in ['builtins', 'runtimes']:
                         continue
                 install_targets.append('install-{}'.format(component))
 
diff --git a/utils/swift_build_support/swift_build_support/products/minimalstdlib.py b/utils/swift_build_support/swift_build_support/products/minimalstdlib.py
index 38f0b73402f7b..276ed8020107d 100644
--- a/utils/swift_build_support/swift_build_support/products/minimalstdlib.py
+++ b/utils/swift_build_support/swift_build_support/products/minimalstdlib.py
@@ -67,8 +67,12 @@ def build(self, host_target):
         self.cmake_options.define(
             'SWIFT_FREESTANDING_MODULE_NAME:STRING', 'macos')
         self.cmake_options.define('SWIFT_FREESTANDING_SDK:STRING', 'macosx')
+        self.cmake_options.define('SWIFT_FREESTANDING_DEPLOYMENT_VERSION:STRING',
+                                  '11.0')
         self.cmake_options.define(
             'SWIFT_FREESTANDING_TRIPLE_NAME:STRING', 'macosx11.0')
+        self.cmake_options.define(
+            'SWIFT_FREESTANDING_AVAILABILITY_NAME:STRING', 'macOS')
         self.cmake_options.define(
             'SWIFT_PRIMARY_VARIANT_ARCH:STRING', 'x86_64')
         self.cmake_options.define(
diff --git a/utils/swift_build_support/swift_build_support/products/product.py b/utils/swift_build_support/swift_build_support/products/product.py
index 8e675f228a29f..dad4a53907596 100644
--- a/utils/swift_build_support/swift_build_support/products/product.py
+++ b/utils/swift_build_support/swift_build_support/products/product.py
@@ -212,11 +212,17 @@ def install_toolchain_path(self, host_target):
         if self.args.cross_compile_hosts:
             if self.is_darwin_host(host_target):
                 install_destdir = self.host_install_destdir(host_target)
-            else:
+            elif self.args.cross_compile_append_host_target_to_destdir:
                 install_destdir = os.path.join(install_destdir, self.args.host_target)
         return targets.toolchain_path(install_destdir,
                                       self.args.install_prefix)
 
+    def native_clang_tools_path(self, host_target):
+        if self.args.native_clang_tools_path is not None:
+            return os.path.split(self.args.native_clang_tools_path)[0]
+        else:
+            return self.install_toolchain_path(host_target)
+
     def native_toolchain_path(self, host_target):
         if self.args.native_swift_tools_path is not None:
             return os.path.split(self.args.native_swift_tools_path)[0]
@@ -389,7 +395,7 @@ def get_linux_target(self, platform, arch):
         sysroot_arch, vendor, abi = self.get_linux_target_components(arch)
         return '{}-{}-linux-{}'.format(sysroot_arch, vendor, abi)
 
-    def generate_linux_toolchain_file(self, platform, arch):
+    def generate_linux_toolchain_file(self, platform, arch, crosscompiling=True):
         """
         Generates a new CMake tolchain file that specifies Linux as a target
         platform.
@@ -402,18 +408,34 @@ def generate_linux_toolchain_file(self, platform, arch):
 
         toolchain_args = {}
 
-        toolchain_args['CMAKE_SYSTEM_NAME'] = 'Linux'
-        toolchain_args['CMAKE_SYSTEM_PROCESSOR'] = arch
+        if crosscompiling:
+            if platform == "linux":
+                toolchain_args['CMAKE_SYSTEM_NAME'] = 'Linux'
+                toolchain_args['CMAKE_SYSTEM_PROCESSOR'] = arch
+            elif platform == "android":
+                toolchain_args['CMAKE_SYSTEM_NAME'] = 'Android'
+                toolchain_args['CMAKE_SYSTEM_VERSION'] = self.args.android_api_level
+                toolchain_args['CMAKE_SYSTEM_PROCESSOR'] = arch if not arch == 'armv7' \
+                                                           else 'armv7-a'
+                toolchain_args['CMAKE_ANDROID_NDK'] = self.args.android_ndk
+                toolchain_args['CMAKE_FIND_ROOT_PATH'] = self.args.cross_compile_deps_path
+                # This is a workaround for a CMake 3.30+ bug,
+                # https://gitlab.kitware.com/cmake/cmake/-/issues/26154, and can
+                # be removed once that is fixed.
+                toolchain_args['CMAKE_SHARED_LINKER_FLAGS'] = '\"\"'
 
         # We only set the actual sysroot if we are actually cross
         # compiling. This is important since otherwise cmake seems to change the
         # RUNPATH to be a relative rather than an absolute path, breaking
         # certain cmark tests (and maybe others).
-        maybe_sysroot = self.get_linux_sysroot(platform, arch)
-        if maybe_sysroot is not None:
-            toolchain_args['CMAKE_SYSROOT'] = maybe_sysroot
-
-        target = self.get_linux_target(platform, arch)
+        if platform == "linux":
+            maybe_sysroot = self.get_linux_sysroot(platform, arch)
+            if maybe_sysroot is not None:
+                toolchain_args['CMAKE_SYSROOT'] = maybe_sysroot
+
+            target = self.get_linux_target(platform, arch)
+        elif platform == "android":
+            target = '%s-unknown-linux-android%s' % (arch, self.args.android_api_level)
         if self.toolchain.cc.endswith('clang'):
             toolchain_args['CMAKE_C_COMPILER_TARGET'] = target
         if self.toolchain.cxx.endswith('clang++'):
@@ -459,10 +481,30 @@ def generate_toolchain_file_for_darwin_or_linux(
                 platform, arch,
                 macos_deployment_version=override_macos_deployment_version)
             self.cmake_options.define('CMAKE_TOOLCHAIN_FILE:PATH', toolchain_file)
-        elif platform == "linux":
-            toolchain_file = self.generate_linux_toolchain_file(platform, arch)
+        elif platform == "linux" or platform == "android":
+            # Always cross-compile for linux, but not on Android, as a native
+            # compile on Android does not use the NDK and its CMake config.
+            cross_compile = platform == "linux" or \
+                self.is_cross_compile_target(host_target)
+            toolchain_file = self.generate_linux_toolchain_file(platform, arch,
+                                                                cross_compile)
             self.cmake_options.define('CMAKE_TOOLCHAIN_FILE:PATH', toolchain_file)
 
+            if cross_compile and platform == "android":
+                resource_dir = None
+                # build-script-impl products build before the install and use
+                # the Swift stdlib from the compiler build directory instead,
+                # while products built even before that currently do not support
+                # cross-compiling Swift.
+                if not self.is_before_build_script_impl_product() and \
+                   not self.is_build_script_impl_product():
+                    install_path = self.host_install_destdir(host_target) + \
+                        self.args.install_prefix
+                    resource_dir = '%s/lib/swift' % install_path
+                flags = targets.StdlibDeploymentTarget.get_target_for_name(
+                    host_target).platform.swift_flags(self.args, resource_dir)
+                self.cmake_options.define('CMAKE_Swift_FLAGS', flags)
+
         return toolchain_file
 
     def get_openbsd_toolchain_file(self):
diff --git a/utils/swift_build_support/swift_build_support/products/swift.py b/utils/swift_build_support/swift_build_support/products/swift.py
index 483be3b409d1c..80fb099da8b29 100644
--- a/utils/swift_build_support/swift_build_support/products/swift.py
+++ b/utils/swift_build_support/swift_build_support/products/swift.py
@@ -10,6 +10,8 @@
 #
 # ----------------------------------------------------------------------------
 
+import os
+
 from build_swift.build_swift.constants import SWIFT_REPO_NAME
 
 from . import cmark
@@ -104,6 +106,11 @@ def __init__(self, args, toolchain, source_dir, build_dir):
         self.cmake_options.extend(
             self._enable_new_runtime_build)
 
+        self.cmake_options.extend(
+            self._darwin_test_deployment_versions)
+
+        self.cmake_options.extend_raw(self.args.extra_swift_cmake_options)
+
     @classmethod
     def product_source_name(cls):
         """product_source_name() -> str
@@ -163,11 +170,18 @@ def _compiler_vendor_flags(self):
     def _version_flags(self):
         r = CMakeOptions()
         if self.args.swift_compiler_version is not None:
-            swift_compiler_version = self.args.swift_compiler_version
-            r.define('SWIFT_COMPILER_VERSION', str(swift_compiler_version))
+            swift_compiler_version = str(self.args.swift_compiler_version)
+            r.define('SWIFT_COMPILER_VERSION', swift_compiler_version)
+            r.define('SWIFT_TOOLCHAIN_VERSION', "swiftlang-" + swift_compiler_version)
+        else:
+            toolchain_version = os.environ.get('TOOLCHAIN_VERSION')
+            if toolchain_version:
+                r.define('SWIFT_TOOLCHAIN_VERSION', toolchain_version)
+
         if self.args.clang_compiler_version is not None:
             clang_compiler_version = self.args.clang_compiler_version
             r.define('CLANG_COMPILER_VERSION', str(clang_compiler_version))
+
         return r
 
     @property
@@ -296,6 +310,19 @@ def _enable_new_runtime_build(self):
         return [('SWIFT_ENABLE_NEW_RUNTIME_BUILD:BOOL',
                  self.args.enable_new_runtime_build)]
 
+    @property
+    def _darwin_test_deployment_versions(self):
+        return [('SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX:STRING',
+                 self.args.darwin_test_deployment_version_osx),
+                 ('SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS:STRING',
+                   self.args.darwin_test_deployment_version_ios),
+                 ('SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS:STRING',
+                   self.args.darwin_test_deployment_version_tvos),
+                 ('SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS:STRING',
+                   self.args.darwin_test_deployment_version_watchos),
+                 ('SWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS:STRING',
+                   self.args.darwin_test_deployment_version_xros)]
+
     def _handle_swift_debuginfo_non_lto_args(self):
         if ('swift_debuginfo_non_lto_args' not in self.args
                 or self.args.swift_debuginfo_non_lto_args is None):
diff --git a/utils/swift_build_support/swift_build_support/products/swift_testing.py b/utils/swift_build_support/swift_build_support/products/swift_testing.py
index 324d1a77eeaa8..177ea9f06232d 100644
--- a/utils/swift_build_support/swift_build_support/products/swift_testing.py
+++ b/utils/swift_build_support/swift_build_support/products/swift_testing.py
@@ -112,6 +112,8 @@ def build(self, host_target):
 
         self.cmake_options.define('CMAKE_BUILD_TYPE', self.args.build_variant)
 
+        self.cmake_options.define('CMAKE_Swift_COMPILATION_MODE', 'wholemodule')
+
         # FIXME: If we build macros for the builder, specify the path.
         self.cmake_options.define('SwiftTesting_MACRO', 'NO')
 
@@ -125,3 +127,11 @@ def install(self, host_target):
         install_prefix = install_destdir + self.args.install_prefix
 
         self.install_with_cmake(['install'], install_prefix)
+
+    @classmethod
+    def is_build_script_impl_product(cls):
+        return False
+
+    @classmethod
+    def is_before_build_script_impl_product(cls):
+        return False
diff --git a/utils/swift_build_support/swift_build_support/products/swift_testing_macros.py b/utils/swift_build_support/swift_build_support/products/swift_testing_macros.py
index ddb3b553de734..d127424709c57 100644
--- a/utils/swift_build_support/swift_build_support/products/swift_testing_macros.py
+++ b/utils/swift_build_support/swift_build_support/products/swift_testing_macros.py
@@ -42,13 +42,24 @@ def should_clean(self, host_target):
         return True
 
     def should_build(self, host_target):
-        return True
+        build_macros = not self.is_cross_compile_target(host_target) or \
+            self.args.cross_compile_build_swift_tools
+        if not build_macros:
+            print("Skipping building Testing Macros for %s, because the host tools "
+                  "are not being built" % host_target)
+        return build_macros
 
     def should_test(self, host_target):
         return False
 
     def should_install(self, host_target):
-        return self.args.install_swift_testing_macros
+        install_macros = self.args.install_swift_testing_macros and \
+            (not self.is_cross_compile_target(host_target) or
+             self.args.cross_compile_build_swift_tools)
+        if self.args.install_swift_testing_macros and not install_macros:
+            print("Skipping installing Testing Macros for %s, because the host tools "
+                  "are not being built" % host_target)
+        return install_macros
 
     def _cmake_product(self, host_target):
         build_root = os.path.dirname(self.build_dir)
@@ -121,3 +132,11 @@ def install(self, host_target):
         install_prefix = install_destdir + self.args.install_prefix
 
         self.install_with_cmake(['install'], install_prefix)
+
+    @classmethod
+    def is_build_script_impl_product(cls):
+        return False
+
+    @classmethod
+    def is_before_build_script_impl_product(cls):
+        return False
diff --git a/utils/swift_build_support/swift_build_support/products/swiftfoundationtests.py b/utils/swift_build_support/swift_build_support/products/swiftfoundationtests.py
index a363fe9024a70..5b9a0a746489b 100644
--- a/utils/swift_build_support/swift_build_support/products/swiftfoundationtests.py
+++ b/utils/swift_build_support/swift_build_support/products/swiftfoundationtests.py
@@ -53,7 +53,10 @@ def should_test(self, host_target):
         return self.args.test_foundation
 
     def configuration(self):
-        return 'release' if self.is_release() else 'debug'
+        if self.args.foundation_tests_build_variant in ['Release', 'RelWithDebInfo']:
+            return 'release'
+        else:
+            return 'debug'
 
     def test(self, host_target):
         swift_exec = os.path.join(
diff --git a/utils/swift_build_support/swift_build_support/products/swiftpm.py b/utils/swift_build_support/swift_build_support/products/swiftpm.py
index ae2a45c8c6500..5a3e938637718 100644
--- a/utils/swift_build_support/swift_build_support/products/swiftpm.py
+++ b/utils/swift_build_support/swift_build_support/products/swiftpm.py
@@ -54,8 +54,9 @@ def run_bootstrap_script(
             self.source_dir, 'Utilities', 'bootstrap')
 
         toolchain_path = self.native_toolchain_path(host_target)
+        clang_tools_path = self.native_clang_tools_path(host_target)
         swiftc = os.path.join(toolchain_path, "bin", "swiftc")
-        clang = os.path.join(toolchain_path, "bin", "clang")
+        clang = os.path.join(clang_tools_path, "bin", "clang")
 
         # FIXME: We require llbuild build directory in order to build. Is
         # there a better way to get this?
@@ -123,7 +124,6 @@ def build(self, host_target):
             host_target,
             additional_params=[
                 "--reconfigure",
-                "--verbose",
             ],
         )
 
@@ -136,7 +136,6 @@ def test(self, host_target):
             host_target,
             compile_only_for_running_host_architecture=True,
             additional_params=[
-                '--verbose'
             ]
         )
 
@@ -154,7 +153,6 @@ def install(self, host_target):
         install_prefix = install_destdir + self.args.install_prefix
 
         self.run_bootstrap_script('install', host_target, [
-            '--verbose',
             '--prefix', install_prefix
         ])
 
diff --git a/utils/swift_build_support/swift_build_support/products/wasisysroot.py b/utils/swift_build_support/swift_build_support/products/wasisysroot.py
index 712a07e8377b4..d6f84b1deb5eb 100644
--- a/utils/swift_build_support/swift_build_support/products/wasisysroot.py
+++ b/utils/swift_build_support/swift_build_support/products/wasisysroot.py
@@ -12,6 +12,7 @@
 
 import multiprocessing
 import os
+import sys
 
 from . import cmake_product
 from . import llvm
@@ -44,53 +45,52 @@ def should_install(self, host_target):
         return False
 
     def build(self, host_target):
-        self._build(host_target)
+        self._build(host_target, thread_model='single',
+                    target_triple='wasm32-wasip1')
         self._build(host_target, thread_model='posix',
                     target_triple='wasm32-wasip1-threads')
 
-    def _build(self, host_target, thread_model='single', target_triple='wasm32-wasi'):
+    def _build(self, host_target, thread_model, target_triple):
         build_root = os.path.dirname(self.build_dir)
-        llvm_build_bin_dir = os.path.join(
-            '..', build_root, '%s-%s' % ('llvm', host_target), 'bin')
-        llvm_tools_path = self.args.native_llvm_tools_path or llvm_build_bin_dir
-        clang_tools_path = self.args.native_clang_tools_path or llvm_build_bin_dir
+
+        if self.args.build_runtime_with_host_compiler:
+            clang_path = self.toolchain.cc
+            ar_path = self.toolchain.llvm_ar
+            nm_path = self.toolchain.llvm_nm
+
+            if not ar_path:
+                print(f"error: `llvm-ar` not found for LLVM toolchain at {clang_path}, "
+                "select a toolchain that has `llvm-ar` included", file=sys.stderr)
+                sys.exit(1)
+        else:
+            llvm_build_bin_dir = os.path.join(
+                '..', build_root, '%s-%s' % ('llvm', host_target), 'bin')
+            llvm_tools_path = self.args.native_llvm_tools_path or llvm_build_bin_dir
+            clang_tools_path = self.args.native_clang_tools_path or llvm_build_bin_dir
+            clang_path = os.path.join(clang_tools_path, 'clang')
+            ar_path = os.path.join(llvm_tools_path, 'llvm-ar')
+            nm_path = os.path.join(llvm_tools_path, 'llvm-nm')
+
         build_jobs = self.args.build_jobs or multiprocessing.cpu_count()
 
         sysroot_build_dir = WASILibc.sysroot_build_path(
             build_root, host_target, target_triple)
-        # FIXME: Manually create an empty dir that is usually created during
-        # check-symbols. The directory is required during sysroot installation step.
-        os.makedirs(os.path.join(sysroot_build_dir, "share"), exist_ok=True)
 
         sysroot_install_path = WASILibc.sysroot_install_path(build_root, target_triple)
         shell.call([
             'make', 'install',
             '-j', str(build_jobs),
-            # FIXME: wasi-libc's pre-defined macro list does not expect
-            # `__FPCLASS_XXX`, which is introduced by the LLVM 17, yet.
-            # So skip the symbol check step by treating the phony target
-            # as very old file.
-            # https://github.com/llvm/llvm-project/commit/7dd387d2971d7759cadfffeb2082439f6c7ddd49
-            '--old-file=check-symbols',
             '-C', self.source_dir,
             'OBJDIR=' + os.path.join(self.build_dir, 'obj-' + thread_model),
             'SYSROOT=' + sysroot_build_dir,
             'INSTALL_DIR=' + sysroot_install_path,
-            'CC=' + os.path.join(clang_tools_path, 'clang'),
-            'AR=' + os.path.join(llvm_tools_path, 'llvm-ar'),
-            'NM=' + os.path.join(llvm_tools_path, 'llvm-nm'),
+            'CC=' + clang_path,
+            'AR=' + ar_path,
+            'NM=' + nm_path,
             'THREAD_MODEL=' + thread_model,
             'TARGET_TRIPLE=' + target_triple,
         ])
 
-        if target_triple == "wasm32-wasi":
-            # Alias wasm32-wasip1 to wasm32-wasi as Embedded modules use
-            # wasm32-unknown-wasip1 as the target triple.
-            for subpath in ["lib", "include"]:
-                dest_path = os.path.join(sysroot_install_path, subpath, "wasm32-wasip1")
-                if not os.path.exists(dest_path):
-                    shell.symlink("wasm32-wasi", dest_path)
-
     @classmethod
     def get_dependencies(cls):
         return [llvm.LLVM]
@@ -139,53 +139,73 @@ def should_install(self, host_target):
         return False
 
     def build(self, host_target):
-        self._build(host_target)
+        self._build(host_target, enable_wasi_threads=False,
+                    compiler_rt_os_dir='wasip1', target_triple='wasm32-wasip1')
+        self._build(host_target, enable_wasi_threads=True,
+                    compiler_rt_os_dir='wasip1', target_triple='wasm32-wasip1-threads')
+
+    def _build(self, host_target, enable_wasi_threads, compiler_rt_os_dir, target_triple):
+        cmake = cmake_product.CMakeProduct(
+            args=self.args,
+            toolchain=self.toolchain,
+            source_dir=self.source_dir,
+            build_dir=os.path.join(self.build_dir, target_triple))
 
-    def _build(self, host_target, enable_wasi_threads=False,
-               compiler_rt_os_dir='wasi', target_triple='wasm32-wasi'):
         build_root = os.path.dirname(self.build_dir)
-        llvm_build_bin_dir = os.path.join(
-            '..', build_root, '%s-%s' % ('llvm', host_target), 'bin')
-        llvm_tools_path = self.args.native_llvm_tools_path or llvm_build_bin_dir
-        clang_tools_path = self.args.native_clang_tools_path or llvm_build_bin_dir
+
+        if self.args.build_runtime_with_host_compiler:
+            cc_path = self.toolchain.cc
+            cxx_path = self.toolchain.cxx
+            ar_path = self.toolchain.llvm_ar
+            ranlib_path = self.toolchain.llvm_ranlib
+
+            if not ar_path:
+                print(f"error: `llvm-ar` not found for LLVM toolchain at {cc_path}, "
+                "select a toolchain that has `llvm-ar` included", file=sys.stderr)
+                sys.exit(1)
+        else:
+            llvm_build_bin_dir = os.path.join(
+                '..', build_root, '%s-%s' % ('llvm', host_target), 'bin')
+            llvm_tools_path = cmake.args.native_llvm_tools_path or llvm_build_bin_dir
+            clang_tools_path = cmake.args.native_clang_tools_path or llvm_build_bin_dir
+            ar_path = os.path.join(llvm_tools_path, 'llvm-ar')
+            ranlib_path = os.path.join(llvm_tools_path, 'llvm-ranlib')
+            cc_path = os.path.join(clang_tools_path, 'clang')
+            cxx_path = os.path.join(clang_tools_path, 'clang++')
 
         cmake_has_threads = 'TRUE' if enable_wasi_threads else 'FALSE'
 
-        self.cmake_options.define(
+        cmake.cmake_options.define(
             'CMAKE_SYSROOT:PATH',
             WASILibc.sysroot_build_path(build_root, host_target, target_triple))
         enable_runtimes = ['libcxx', 'libcxxabi', 'compiler-rt']
-        self.cmake_options.define('LLVM_ENABLE_RUNTIMES:STRING',
-                                  ';'.join(enable_runtimes))
+        cmake.cmake_options.define('LLVM_ENABLE_RUNTIMES:STRING',
+                                   ';'.join(enable_runtimes))
 
         libdir_suffix = '/' + target_triple
-        self.cmake_options.define('LIBCXX_LIBDIR_SUFFIX:STRING', libdir_suffix)
-        self.cmake_options.define('LIBCXXABI_LIBDIR_SUFFIX:STRING', libdir_suffix)
-        self.cmake_options.define('CMAKE_STAGING_PREFIX:PATH', '/')
-
-        self.cmake_options.define('COMPILER_RT_DEFAULT_TARGET_ARCH:STRING', 'wasm32')
-        self.cmake_options.define('COMPILER_RT_DEFAULT_TARGET_ONLY:BOOL', 'TRUE')
-        self.cmake_options.define('COMPILER_RT_BAREMETAL_BUILD:BOOL', 'TRUE')
-        self.cmake_options.define('COMPILER_RT_BUILD_XRAY:BOOL', 'FALSE')
-        self.cmake_options.define('COMPILER_RT_BUILD_PROFILE:BOOL', 'TRUE')
-        self.cmake_options.define('COMPILER_RT_INCLUDE_TESTS:BOOL', 'FALSE')
-        self.cmake_options.define('COMPILER_RT_HAS_FPIC_FLAG:BOOL', 'FALSE')
-        self.cmake_options.define('COMPILER_RT_EXCLUDE_ATOMIC_BUILTIN:BOOL', 'FALSE')
-        self.cmake_options.define('COMPILER_RT_OS_DIR:STRING', compiler_rt_os_dir)
-
-        self.cmake_options.define('CMAKE_C_COMPILER_WORKS:BOOL', 'TRUE')
-        self.cmake_options.define('CMAKE_CXX_COMPILER_WORKS:BOOL', 'TRUE')
-
-        self.cmake_options.define('CMAKE_SYSTEM_NAME:STRING', 'WASI')
-        self.cmake_options.define('CMAKE_SYSTEM_PROCESSOR:STRING', 'wasm32')
-        self.cmake_options.define('CMAKE_AR:FILEPATH',
-                                  os.path.join(llvm_tools_path, 'llvm-ar'))
-        self.cmake_options.define('CMAKE_RANLIB:FILEPATH',
-                                  os.path.join(llvm_tools_path, 'llvm-ranlib'))
-        self.cmake_options.define('CMAKE_C_COMPILER:FILEPATH',
-                                  os.path.join(clang_tools_path, 'clang'))
-        self.cmake_options.define('CMAKE_CXX_COMPILER:STRING',
-                                  os.path.join(clang_tools_path, 'clang++'))
+        cmake.cmake_options.define('LIBCXX_LIBDIR_SUFFIX:STRING', libdir_suffix)
+        cmake.cmake_options.define('LIBCXXABI_LIBDIR_SUFFIX:STRING', libdir_suffix)
+        cmake.cmake_options.define('CMAKE_STAGING_PREFIX:PATH', '/')
+
+        cmake.cmake_options.define('COMPILER_RT_DEFAULT_TARGET_ARCH:STRING', 'wasm32')
+        cmake.cmake_options.define('COMPILER_RT_DEFAULT_TARGET_ONLY:BOOL', 'TRUE')
+        cmake.cmake_options.define('COMPILER_RT_BAREMETAL_BUILD:BOOL', 'TRUE')
+        cmake.cmake_options.define('COMPILER_RT_BUILD_XRAY:BOOL', 'FALSE')
+        cmake.cmake_options.define('COMPILER_RT_BUILD_PROFILE:BOOL', 'TRUE')
+        cmake.cmake_options.define('COMPILER_RT_INCLUDE_TESTS:BOOL', 'FALSE')
+        cmake.cmake_options.define('COMPILER_RT_HAS_FPIC_FLAG:BOOL', 'FALSE')
+        cmake.cmake_options.define('COMPILER_RT_EXCLUDE_ATOMIC_BUILTIN:BOOL', 'FALSE')
+        cmake.cmake_options.define('COMPILER_RT_OS_DIR:STRING', compiler_rt_os_dir)
+
+        cmake.cmake_options.define('CMAKE_C_COMPILER_WORKS:BOOL', 'TRUE')
+        cmake.cmake_options.define('CMAKE_CXX_COMPILER_WORKS:BOOL', 'TRUE')
+
+        cmake.cmake_options.define('CMAKE_SYSTEM_NAME:STRING', 'WASI')
+        cmake.cmake_options.define('CMAKE_SYSTEM_PROCESSOR:STRING', 'wasm32')
+        cmake.cmake_options.define('CMAKE_AR:FILEPATH', ar_path)
+        cmake.cmake_options.define('CMAKE_RANLIB:FILEPATH', ranlib_path)
+        cmake.cmake_options.define('CMAKE_C_COMPILER:FILEPATH', cc_path)
+        cmake.cmake_options.define('CMAKE_CXX_COMPILER:STRING', cxx_path)
 
         c_flags = []
         # Explicitly disable exceptions even though it's usually implicitly disabled by
@@ -196,51 +216,46 @@ def _build(self, host_target, enable_wasi_threads=False,
         if enable_wasi_threads:
             c_flags.append('-pthread')
             cxx_flags.append('-pthread')
-        self.cmake_options.define('CMAKE_C_FLAGS:STRING', ' '.join(c_flags))
-        self.cmake_options.define('CMAKE_CXX_FLAGS:STRING', ' '.join(cxx_flags))
-
-        self.cmake_options.define('CMAKE_C_COMPILER_TARGET:STRING', target_triple)
-        self.cmake_options.define('CMAKE_CXX_COMPILER_TARGET:STRING', target_triple)
-
-        self.cmake_options.define('CXX_SUPPORTS_CXX11:BOOL', 'TRUE')
-
-        self.cmake_options.define('LIBCXX_ENABLE_THREADS:BOOL', cmake_has_threads)
-        self.cmake_options.define('LIBCXX_HAS_PTHREAD_API:BOOL', cmake_has_threads)
-        self.cmake_options.define('LIBCXX_HAS_EXTERNAL_THREAD_API:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXX_HAS_WIN32_THREAD_API:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXX_ENABLE_SHARED:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXX_ENABLE_EXCEPTIONS:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXX_ENABLE_FILESYSTEM:BOOL', 'TRUE')
-        self.cmake_options.define('LIBCXX_CXX_ABI', 'libcxxabi')
-        self.cmake_options.define('LIBCXX_HAS_MUSL_LIBC:BOOL', 'TRUE')
-
-        self.cmake_options.define('LIBCXX_ABI_VERSION', '2')
-        self.cmake_options.define('LIBCXXABI_ENABLE_EXCEPTIONS:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXXABI_ENABLE_SHARED:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXXABI_USE_LLVM_UNWINDER:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXXABI_SILENT_TERMINATE:BOOL', 'TRUE')
-        self.cmake_options.define('LIBCXXABI_ENABLE_THREADS:BOOL', cmake_has_threads)
-        self.cmake_options.define('LIBCXXABI_HAS_PTHREAD_API:BOOL', cmake_has_threads)
-        self.cmake_options.define('LIBCXXABI_HAS_EXTERNAL_THREAD_API:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL',
-                                  'FALSE')
-        self.cmake_options.define('LIBCXXABI_HAS_WIN32_THREAD_API:BOOL', 'FALSE')
-        self.cmake_options.define('LIBCXXABI_ENABLE_PIC:BOOL', 'FALSE')
-        self.cmake_options.define('UNIX:BOOL', 'TRUE')
-
-        self.build_with_cmake([], self.args.build_variant, [],
-                              prefer_native_toolchain=True)
-        self.install_with_cmake(
+        cmake.cmake_options.define('CMAKE_C_FLAGS:STRING', ' '.join(c_flags))
+        cmake.cmake_options.define('CMAKE_CXX_FLAGS:STRING', ' '.join(cxx_flags))
+
+        cmake.cmake_options.define('CMAKE_C_COMPILER_TARGET:STRING', target_triple)
+        cmake.cmake_options.define('CMAKE_CXX_COMPILER_TARGET:STRING', target_triple)
+
+        cmake.cmake_options.define('CXX_SUPPORTS_CXX11:BOOL', 'TRUE')
+
+        cmake.cmake_options.define('LIBCXX_ENABLE_THREADS:BOOL', cmake_has_threads)
+        cmake.cmake_options.define('LIBCXX_HAS_PTHREAD_API:BOOL', cmake_has_threads)
+        cmake.cmake_options.define('LIBCXX_HAS_EXTERNAL_THREAD_API:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXX_HAS_WIN32_THREAD_API:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXX_ENABLE_SHARED:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXX_ENABLE_EXCEPTIONS:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXX_ENABLE_FILESYSTEM:BOOL', 'TRUE')
+        cmake.cmake_options.define('LIBCXX_CXX_ABI', 'libcxxabi')
+        cmake.cmake_options.define('LIBCXX_HAS_MUSL_LIBC:BOOL', 'TRUE')
+
+        cmake.cmake_options.define('LIBCXX_ABI_VERSION', '2')
+        cmake.cmake_options.define('LIBCXXABI_ENABLE_EXCEPTIONS:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXXABI_ENABLE_SHARED:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXXABI_USE_LLVM_UNWINDER:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXXABI_SILENT_TERMINATE:BOOL', 'TRUE')
+        cmake.cmake_options.define('LIBCXXABI_ENABLE_THREADS:BOOL', cmake_has_threads)
+        cmake.cmake_options.define('LIBCXXABI_HAS_PTHREAD_API:BOOL', cmake_has_threads)
+        cmake.cmake_options.define('LIBCXXABI_HAS_EXTERNAL_THREAD_API:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL',
+                                   'FALSE')
+        cmake.cmake_options.define('LIBCXXABI_HAS_WIN32_THREAD_API:BOOL', 'FALSE')
+        cmake.cmake_options.define('LIBCXXABI_ENABLE_PIC:BOOL', 'FALSE')
+        cmake.cmake_options.define('UNIX:BOOL', 'TRUE')
+
+        cmake.build_with_cmake([], cmake.args.build_variant, [],
+                               prefer_native_toolchain=not self.args.build_runtime_with_host_compiler,
+                               ignore_extra_cmake_options=True)
+        cmake.install_with_cmake(
             ["install"], WASILibc.sysroot_install_path(build_root, target_triple))
 
     @classmethod
     def get_dependencies(cls):
         return [WASILibc, llvm.LLVM]
-
-
-class WasmThreadsLLVMRuntimeLibs(WasmLLVMRuntimeLibs):
-    def build(self, host_target):
-        self._build(host_target, enable_wasi_threads=True,
-                    compiler_rt_os_dir='wasip1', target_triple='wasm32-wasip1-threads')
diff --git a/utils/swift_build_support/swift_build_support/products/wasmkit.py b/utils/swift_build_support/swift_build_support/products/wasmkit.py
index 0b589ece4b509..40edea918e5f3 100644
--- a/utils/swift_build_support/swift_build_support/products/wasmkit.py
+++ b/utils/swift_build_support/swift_build_support/products/wasmkit.py
@@ -14,6 +14,7 @@
 import shutil
 
 from . import product
+from . import swiftpm
 from .. import shell
 
 
@@ -37,7 +38,7 @@ def is_before_build_script_impl_product(cls):
 
     @classmethod
     def get_dependencies(cls):
-        return []
+        return [swiftpm.SwiftPM]
 
     def should_build(self, host_target):
         return self.args.build_wasmkit
@@ -46,39 +47,61 @@ def should_test(self, host_target):
         return False
 
     def should_install(self, host_target):
-        # Currently, it's only used for testing stdlib.
-        return False
+        return self.args.install_wasmkit
 
     def install(self, host_target):
-        pass
+        """
+        Install WasmKit to the target location
+        """
+        install_destdir = self.host_install_destdir(host_target)
+        build_toolchain_path = install_destdir + self.args.install_prefix + '/bin'
+        bin_path = run_swift_build(host_target, self, 'wasmkit-cli', set_installation_rpath=True)
+        shutil.copy(bin_path, build_toolchain_path + '/wasmkit')
 
     def build(self, host_target):
         bin_path = run_swift_build(host_target, self, 'wasmkit-cli')
-        print("Built wasmkit-cli at: " + bin_path)
+        print("Built wasmkit-cli at: " + bin_path, flush=True)
         # Copy the built binary to ./bin
         dest_bin_path = self.__class__.cli_file_path(self.build_dir)
-        print("Copying wasmkit-cli to: " + dest_bin_path)
+        print("Copying wasmkit-cli to: " + dest_bin_path, flush=True)
         os.makedirs(os.path.dirname(dest_bin_path), exist_ok=True)
         shutil.copy(bin_path, dest_bin_path)
 
     @classmethod
     def cli_file_path(cls, build_dir):
-        return os.path.join(build_dir, 'bin', 'wasmkit-cli')
-
-
-def run_swift_build(host_target, product, swpft_package_product_name):
-    # Building with the host toolchain's SwiftPM
-    swiftc_path = os.path.abspath(product.toolchain.swiftc)
-    toolchain_path = os.path.dirname(os.path.dirname(swiftc_path))
-    swift_build = os.path.join(toolchain_path, 'bin', 'swift-build')
+        return os.path.join(build_dir, 'bin', 'wasmkit')
+
+
+def run_swift_build(host_target, product, swiftpm_package_product_name, set_installation_rpath=False):
+    swift_build = os.path.join(product.install_toolchain_path(host_target), "bin", "swift-build")
+
+    if not os.path.exists(swift_build) or product.args.build_runtime_with_host_compiler:
+        print(
+            f"WARNING: build-script's {os.path.basename(__file__)} is running local development code path, "
+            "don't use these build artifacts for deployment!"
+        )
+        swift_build = product.toolchain.swift_build
+
+    if host_target.startswith('macos'):
+        # Universal binary on macOS
+        platform_args = ['--arch', 'x86_64', '--arch', 'arm64']
+    elif set_installation_rpath:
+        # Library rpath for swift, dispatch, Foundation, etc. when installing
+        build_os = host_target.split('-')[0]
+        platform_args = [
+            '--disable-local-rpath', '-Xswiftc', '-no-toolchain-stdlib-rpath',
+            '-Xlinker', '-rpath', '-Xlinker', '$ORIGIN/../lib/swift/' + build_os
+        ]
+    else:
+        platform_args = []
 
     build_args = [
         swift_build,
-        '--product', swpft_package_product_name,
+        '--product', swiftpm_package_product_name,
         '--package-path', os.path.join(product.source_dir),
         '--build-path', product.build_dir,
         '--configuration', 'release',
-    ]
+    ] + platform_args
 
     if product.args.verbose_build:
         build_args.append('--verbose')
@@ -90,4 +113,4 @@ def run_swift_build(host_target, product, swpft_package_product_name):
 
     bin_dir_path = shell.capture(
         build_args + ['--show-bin-path'], dry_run=False, echo=False).rstrip()
-    return os.path.join(bin_dir_path, swpft_package_product_name)
+    return os.path.join(bin_dir_path, swiftpm_package_product_name)
diff --git a/utils/swift_build_support/swift_build_support/products/wasmstdlib.py b/utils/swift_build_support/swift_build_support/products/wasmstdlib.py
index 9cf73d3396d1d..18b8021af57e3 100644
--- a/utils/swift_build_support/swift_build_support/products/wasmstdlib.py
+++ b/utils/swift_build_support/swift_build_support/products/wasmstdlib.py
@@ -41,7 +41,7 @@ def should_test(self, host_target):
         return self.args.test_wasmstdlib
 
     def build(self, host_target):
-        self._build(host_target, 'wasm32-wasi', 'wasi-wasm32')
+        self._build(host_target, 'wasm32-wasip1', 'wasip1-wasm32')
 
     def _build(self, host_target, target_triple, short_triple):
         llvm_build_dir = self._configure_llvm(target_triple, short_triple)
@@ -67,9 +67,11 @@ def _configure_llvm(self, target_triple, short_triple):
         cmake_options.define('LLVM_ENABLE_LIBXML2:BOOL', 'FALSE')
         cmake_options.define('LLVM_ENABLE_LIBEDIT:BOOL', 'FALSE')
         cmake_options.define('LLVM_ENABLE_TERMINFO:BOOL', 'FALSE')
+        if self.args.build_runtime_with_host_compiler:
+            cmake_options.define('CMAKE_ASM_COMPILER:PATH', self.toolchain.cc)
 
         llvm_cmake = cmake.CMake(
-            self.args, self.toolchain, prefer_native_toolchain=True)
+            self.args, self.toolchain, prefer_native_toolchain=not self.args.build_runtime_with_host_compiler)
         # Only configure LLVM, not build it because we just need
         # LLVM CMake functionalities
         shell.call(["env", self.toolchain.cmake, "-B", build_dir]
@@ -90,25 +92,35 @@ def _build_stdlib(self, host_target, target_triple, llvm_cmake_dir):
         self.cmake_options.define(
             'SWIFT_STDLIB_BUILD_TYPE:STRING', self._build_variant)
 
-        # Toolchain configuration
-        toolchain_path = self.native_toolchain_path(host_target)
-        # Explicitly set the CMake AR and RANLIB to force it to use llvm-ar/llvm-ranlib
-        # instead of the system ar/ranlib, which usually don't support WebAssembly
-        # object files.
-        self.cmake_options.define('CMAKE_AR:STRING', os.path.join(
-            toolchain_path, 'bin', 'llvm-ar'))
-        self.cmake_options.define('CMAKE_RANLIB:STRING', os.path.join(
-            toolchain_path, 'bin', 'llvm-ranlib'))
-        self.cmake_options.define(
-            'SWIFT_NATIVE_CLANG_TOOLS_PATH:STRING', os.path.join(toolchain_path, 'bin'))
-        self.cmake_options.define(
-            'SWIFT_NATIVE_SWIFT_TOOLS_PATH:STRING', os.path.join(toolchain_path, 'bin'))
-        self.cmake_options.define(
-            'SWIFT_NATIVE_LLVM_TOOLS_PATH:STRING', os.path.join(toolchain_path, 'bin'))
-        self.cmake_options.define(
-            'BOOTSTRAPPING_MODE:STRING', 'CROSSCOMPILE')
-        self.cmake_options.define(
-            'SWIFT_BUILD_RUNTIME_WITH_HOST_COMPILER:BOOL', 'FALSE')
+        if self.args.build_runtime_with_host_compiler:
+            self.cmake_options.define('SWIFT_BUILD_RUNTIME_WITH_HOST_COMPILER:BOOL', "TRUE")
+            self.cmake_options.define(
+                'SWIFT_NATIVE_CLANG_TOOLS_PATH:STRING', os.path.dirname(self.toolchain.cc))
+            self.cmake_options.define(
+                'SWIFT_NATIVE_SWIFT_TOOLS_PATH:STRING', os.path.dirname(self.toolchain.swiftc))
+            self.cmake_options.define(
+                'SWIFT_NATIVE_LLVM_TOOLS_PATH:STRING', os.path.dirname(self.toolchain.llvm_ar))
+        else:
+            # Toolchain configuration
+            toolchain_path = self.native_toolchain_path(host_target)
+            # Explicitly set the CMake AR and RANLIB to force it to use llvm-ar/llvm-ranlib
+            # instead of the system ar/ranlib, which usually don't support WebAssembly
+            # object files.
+            self.cmake_options.define('CMAKE_AR:STRING', os.path.join(
+                toolchain_path, 'bin', 'llvm-ar'))
+            self.cmake_options.define('CMAKE_RANLIB:STRING', os.path.join(
+                toolchain_path, 'bin', 'llvm-ranlib'))
+            self.cmake_options.define(
+                'SWIFT_NATIVE_CLANG_TOOLS_PATH:STRING', os.path.join(toolchain_path, 'bin'))
+            self.cmake_options.define(
+                'SWIFT_NATIVE_SWIFT_TOOLS_PATH:STRING', os.path.join(toolchain_path, 'bin'))
+            self.cmake_options.define(
+                'SWIFT_NATIVE_LLVM_TOOLS_PATH:STRING', os.path.join(toolchain_path, 'bin'))
+            self.cmake_options.define(
+                'BOOTSTRAPPING_MODE:STRING', 'CROSSCOMPILE')
+            self.cmake_options.define(
+                'SWIFT_BUILD_RUNTIME_WITH_HOST_COMPILER:BOOL', 'FALSE')
+
         self.cmake_options.define('SWIFT_WASI_SYSROOT_PATH:STRING',
                                   self._wasi_sysroot_path(target_triple))
 
@@ -167,20 +179,28 @@ def _build_stdlib(self, host_target, target_triple, llvm_cmake_dir):
         self.cmake_options.define('SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB:BOOL', 'TRUE')
         self.cmake_options.define(
             'SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB_CROSS_COMPILING', 'TRUE')
+        self.cmake_options.define(
+            'SWIFT_SDK_embedded_ARCH_wasm32_PATH:PATH',
+            self._wasi_sysroot_path("wasm32-wasip1"))
         self.cmake_options.define(
             'SWIFT_SDK_embedded_ARCH_wasm32-unknown-wasip1_PATH:PATH',
-            self._wasi_sysroot_path("wasm32-wasi"))
+            self._wasi_sysroot_path("wasm32-wasip1"))
 
         self.add_extra_cmake_options()
 
         # Test configuration
         self.cmake_options.define('SWIFT_INCLUDE_TESTS:BOOL', 'TRUE')
         self.cmake_options.define('SWIFT_ENABLE_SOURCEKIT_TESTS:BOOL', 'FALSE')
-        lit_test_paths = ['IRGen', 'stdlib', 'Concurrency/Runtime', 'embedded/wasm']
+        lit_test_paths = [
+            'IRGen', 'stdlib', 'Concurrency/Runtime', 'embedded',
+            # TODO(katei): Enable all interpreter tests
+            'Interpreter/enum.swift',
+        ]
         lit_test_paths = [os.path.join(
             self.build_dir, 'test-wasi-wasm32', path) for path in lit_test_paths]
         self.cmake_options.define('SWIFT_LIT_TEST_PATHS:STRING',
                                   ';'.join(lit_test_paths))
+        self.cmake_options.define('LLVM_LIT_ARGS', self.args.lit_args)
         test_driver_options = [
             # compiler-rt is not installed in the final toolchain, so use one
             # in build dir
@@ -192,12 +212,15 @@ def _build_stdlib(self, host_target, target_triple, llvm_cmake_dir):
 
         # Configure with WebAssembly target variant, and build with just-built toolchain
         self.build_with_cmake([], self._build_variant, [],
-                              prefer_native_toolchain=True)
+                              prefer_native_toolchain=not self.args.build_runtime_with_host_compiler)
 
     def add_extra_cmake_options(self):
         self.cmake_options.define('SWIFT_THREADING_PACKAGE:STRING', 'none')
 
     def test(self, host_target):
+        self._test(host_target, 'wasm32-wasip1')
+
+    def _test(self, host_target, target_triple):
         build_root = os.path.dirname(self.build_dir)
         bin_paths = [
             os.path.join(self._host_swift_build_dir(host_target), 'bin'),
@@ -219,9 +242,16 @@ def test(self, host_target):
             'LIT_FILTER_OUT':
                 '(Concurrency/Runtime/clock.swift|stdlib/StringIndex.swift)',
         }
-        self.test_with_cmake(None, [test_target], self._build_variant, [], test_env=env)
 
-    def should_test_executable(self):
+        # Embedded stdlib is not built for the threads triple, don't include embedded tests for it.
+        if target_triple == 'wasm32-wasip1-threads':
+            test_targets = [test_target]
+        else:
+            test_targets = [test_target, 'check-swift-embedded-wasi']
+
+        self.test_with_cmake(None, test_targets, self._build_variant, [], test_env=env)
+
+    def should_test_executable(self) -> bool:
         return True
 
     @property
@@ -256,6 +286,9 @@ class WasmThreadsStdlib(WasmStdlib):
     def build(self, host_target):
         self._build(host_target, 'wasm32-wasip1-threads', 'wasip1-threads-wasm32')
 
+    def test(self, host_target):
+        self._test(host_target, 'wasm32-wasip1-threads')
+
     def should_test_executable(self):
         # TODO(katei): Enable tests once WasmKit supports WASI threads
         return False
diff --git a/utils/swift_build_support/swift_build_support/products/wasmswiftsdk.py b/utils/swift_build_support/swift_build_support/products/wasmswiftsdk.py
index 4a0ca330301c8..e39da2ed8d747 100644
--- a/utils/swift_build_support/swift_build_support/products/wasmswiftsdk.py
+++ b/utils/swift_build_support/swift_build_support/products/wasmswiftsdk.py
@@ -14,8 +14,8 @@
 
 from . import product
 from . import wasisysroot
-from .swift_testing import SwiftTestingCMakeShim
 from .wasmstdlib import WasmStdlib, WasmThreadsStdlib
+from .cmake_product import CMakeProduct
 from .. import shell
 
 
@@ -41,49 +41,188 @@ def should_test(self, host_target):
     def _target_package_path(self, swift_host_triple):
         return os.path.join(self.build_dir, 'Toolchains', swift_host_triple)
 
-    def _build_swift_testing(self, swift_host_triple, short_triple, wasi_sysroot):
-        # TODO: We currently build swift-testing outside of SwiftTesting
-        #       build-script product because we build Wasm stdlib outside of
-        #       the main Swift build unit and we can't use build-script's cross
-        #       compilation infrastructure.
-        #       Once stdlib build is decoupled from compiler's CMake build unit
-        #       and we can use different CMake options for different targets
-        #       for stdlib build, we can fully unify library builds with the
-        #       regular path.
+    def _append_platform_cmake_options(self, cmake_options, swift_host_triple, has_pthread, wasi_sysroot, extra_swift_flags):
+        cmake_options.define('CMAKE_SYSTEM_NAME:STRING', 'WASI')
+        cmake_options.define('CMAKE_SYSTEM_PROCESSOR:STRING', 'wasm32')
+        cmake_options.define('CMAKE_C_COMPILER_TARGET', swift_host_triple)
+        cmake_options.define('CMAKE_CXX_COMPILER_TARGET', swift_host_triple)
+        cmake_options.define(
+            'CMAKE_Swift_COMPILER_TARGET', swift_host_triple)
+        cmake_options.define('CMAKE_SYSROOT', wasi_sysroot)
+
         dest_dir = self._target_package_path(swift_host_triple)
+        swift_resource_dir = os.path.join(dest_dir, 'usr', 'lib', 'swift_static')
+        clang_resource_dir = os.path.join(swift_resource_dir, 'clang')
+
+        swift_flags = ['-sdk', wasi_sysroot, '-resource-dir',
+                       swift_resource_dir] + extra_swift_flags
+        c_flags = ['-resource-dir', clang_resource_dir]
+        cxx_flags = c_flags + ['-fno-exceptions']
+        if has_pthread:
+            clang_flags = ['-mthread-model', 'posix', '-pthread']
+            c_flags.extend(clang_flags)
+            cxx_flags.extend(clang_flags)
+            swift_flags.extend(['-Xcc', '-matomics', '-Xcc', '-mbulk-memory',
+                               '-Xcc', '-mthread-model', '-Xcc', 'posix', '-Xcc', '-pthread'])
+
+        cmake_options.define('CMAKE_Swift_FLAGS', ' '.join(swift_flags))
+        cmake_options.define('CMAKE_C_FLAGS', ' '.join(c_flags))
+        cmake_options.define('CMAKE_CXX_FLAGS', ' '.join(cxx_flags))
+        cmake_options.define('CMAKE_Swift_COMPILER_FORCED', 'TRUE')
+        cmake_options.define('CMAKE_CXX_COMPILER_FORCED', 'TRUE')
+        cmake_options.define('CMAKE_BUILD_TYPE', self.args.build_variant)
 
-        swift_testing = SwiftTestingCMakeShim(
+        if not self.args.build_runtime_with_host_compiler:
+            # Explicitly choose ar and ranlib from just-built LLVM tools since tools in the host system
+            # unlikely support Wasm object format.
+            native_toolchain_path = self.native_toolchain_path(self.args.host_target)
+            cmake_options.define('CMAKE_AR', os.path.join(
+                native_toolchain_path, 'bin', 'llvm-ar'))
+            cmake_options.define('CMAKE_RANLIB', os.path.join(
+                native_toolchain_path, 'bin', 'llvm-ranlib'))
+
+    def _build_libxml2(self, swift_host_triple, clang_multiarch_triple, has_pthread, wasi_sysroot):
+        libxml2 = CMakeProduct(
             args=self.args,
             toolchain=self.toolchain,
             source_dir=os.path.join(
-                os.path.dirname(self.source_dir), 'swift-testing'),
-            build_dir=os.path.join(
-                os.path.dirname(self.build_dir),
-                'swift-testing-%s' % short_triple))
+                os.path.dirname(self.source_dir), 'libxml2'),
+            build_dir=os.path.join(self.build_dir, 'libxml2', swift_host_triple))
+        self._append_platform_cmake_options(
+            libxml2.cmake_options, swift_host_triple, has_pthread, wasi_sysroot, [])
+        libxml2.cmake_options.define('LIBXML2_WITH_C14N', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_CATALOG', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_DEBUG', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_DOCB', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_FTP', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_HTML', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_HTTP', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_ICONV', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_ICU', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_ISO8859X', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_LEGACY', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_LZMA', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_MEM_DEBUG', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_MODULES', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_OUTPUT', 'TRUE')
+        libxml2.cmake_options.define('LIBXML2_WITH_PATTERN', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_PROGRAMS', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_PUSH', 'TRUE')
+        libxml2.cmake_options.define('LIBXML2_WITH_PYTHON', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_READER', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_REGEXPS', 'TRUE')
+        libxml2.cmake_options.define('LIBXML2_WITH_RUN_DEBUG', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_SAX1', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_SCHEMAS', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_SCHEMATRON', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_TESTS', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_TREE', 'TRUE')
+        libxml2.cmake_options.define('LIBXML2_WITH_VALID', 'TRUE')
+        libxml2.cmake_options.define('LIBXML2_WITH_WRITER', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_XINCLUDE', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_XPATH', 'TRUE')
+        libxml2.cmake_options.define('LIBXML2_WITH_XPTR', 'FALSE')
+        libxml2.cmake_options.define('LIBXML2_WITH_ZLIB', 'FALSE')
+        libxml2.cmake_options.define('BUILD_SHARED_LIBS', 'FALSE')
+        # Install libxml2.a under <sysroot>/lib/<clang_multiarch_triple>
+        # because Clang driver only passes arch-specific library paths as
+        # search paths to the linker for WebAssembly targets.
+        libxml2.cmake_options.define('CMAKE_INSTALL_LIBDIR', f'lib/{clang_multiarch_triple}')
 
-        swift_testing.cmake_options.define('CMAKE_SYSTEM_NAME:STRING', 'WASI')
-        swift_testing.cmake_options.define('CMAKE_SYSTEM_PROCESSOR:STRING', 'wasm32')
-        swift_testing.cmake_options.define(
-            'CMAKE_CXX_COMPILER_TARGET', swift_host_triple)
-        swift_testing.cmake_options.define(
-            'CMAKE_Swift_COMPILER_TARGET', swift_host_triple)
-        swift_testing.cmake_options.define('CMAKE_SYSROOT', wasi_sysroot)
-        swift_resource_dir = os.path.join(dest_dir, 'usr', 'lib', 'swift_static')
-        swift_testing.cmake_options.define(
-            'CMAKE_Swift_FLAGS',
-            f'-sdk {wasi_sysroot} -resource-dir {swift_resource_dir}')
-        clang_resource_dir = os.path.join(dest_dir, 'usr', 'lib', 'clang')
+        cmake_thread_enabled = 'TRUE' if has_pthread else 'FALSE'
+        libxml2.cmake_options.define('LIBXML2_WITH_THREAD_ALLOC', cmake_thread_enabled)
+        libxml2.cmake_options.define('LIBXML2_WITH_THREADS', cmake_thread_enabled)
+        libxml2.cmake_options.define('HAVE_PTHREAD_H', cmake_thread_enabled)
+
+        libxml2.build_with_cmake([], self.args.build_variant, [],
+                                 prefer_native_toolchain=not self.args.build_runtime_with_host_compiler,
+                                 ignore_extra_cmake_options=True)
+        with shell.pushd(libxml2.build_dir):
+            shell.call([self.toolchain.cmake, '--install', '.', '--prefix', '/', '--component', 'development'],
+                       env={'DESTDIR': wasi_sysroot})
+
+    def _build_foundation(self, swift_host_triple, clang_multiarch_triple, has_pthread, wasi_sysroot):
+        source_root = os.path.dirname(self.source_dir)
+        host_toolchain = self.native_toolchain_path(self.args.host_target)
+
+        foundation = CMakeProduct(
+            args=self.args,
+            toolchain=self.toolchain,
+            source_dir=os.path.join(
+                os.path.dirname(self.source_dir), 'swift-corelibs-foundation'),
+            build_dir=os.path.join(self.build_dir, 'foundation', swift_host_triple))
+        self._append_platform_cmake_options(
+            foundation.cmake_options, swift_host_triple, has_pthread, wasi_sysroot, [])
+        foundation.cmake_options.define('BUILD_SHARED_LIBS', 'FALSE')
+        foundation.cmake_options.define('FOUNDATION_BUILD_TOOLS', 'FALSE')
+        foundation.cmake_options.define('_SwiftCollections_SourceDIR', os.path.join(source_root, 'swift-collections'))
+        foundation.cmake_options.define('_SwiftFoundation_SourceDIR', os.path.join(source_root, 'swift-foundation'))
+        foundation.cmake_options.define('_SwiftFoundationICU_SourceDIR', os.path.join(source_root, 'swift-foundation-icu'))
+        foundation.cmake_options.define('SwiftFoundation_MACRO', os.path.join(host_toolchain, 'lib', 'swift', 'host', 'plugins'))
+        # Teach CMake to use wasi-sysroot for finding packages through `find_package`.
+        # With `CMAKE_LIBRARY_ARCHITECTURE`, CMake will search for libraries in
+        # `<sysroot>/lib/<clang_multiarch_triple>/cmake/<name>*/<name>-config.cmake`,
+        # which is the location where libxml2 installs its CMake config files.
+        # See https://cmake.org/cmake/help/latest/command/find_package.html#search-procedure
+        foundation.cmake_options.define('CMAKE_PREFIX_PATH', wasi_sysroot)
+        foundation.cmake_options.define('CMAKE_LIBRARY_ARCHITECTURE', clang_multiarch_triple)
+
+        foundation.build_with_cmake([], self.args.build_variant, [],
+                                    prefer_native_toolchain=not self.args.build_runtime_with_host_compiler,
+                                    ignore_extra_cmake_options=True)
+
+        dest_dir = self._target_package_path(swift_host_triple)
+        with shell.pushd(foundation.build_dir):
+            shell.call([self.toolchain.cmake, '--install', '.', '--prefix', '/usr'],
+                       env={'DESTDIR': dest_dir})
+
+    def _build_swift_testing(self, swift_host_triple, has_pthread, wasi_sysroot):
+        swift_testing = CMakeProduct(
+            args=self.args,
+            toolchain=self.toolchain,
+            source_dir=os.path.join(
+                os.path.dirname(self.source_dir), 'swift-testing'),
+            build_dir=os.path.join(self.build_dir, 'swift-testing', swift_host_triple))
+        # For statically linked objects in an archive, we have to use singlethreaded
+        # LLVM codegen unit to prevent runtime metadata sections from being stripped
+        # at link-time.
+        self._append_platform_cmake_options(
+            swift_testing.cmake_options, swift_host_triple, has_pthread, wasi_sysroot,
+            extra_swift_flags=['-Xfrontend', '-enable-single-module-llvm-emission'])
+        swift_testing.cmake_options.define('BUILD_SHARED_LIBS', 'FALSE')
         swift_testing.cmake_options.define(
-            'CMAKE_CXX_FLAGS', f'-resource-dir {clang_resource_dir}')
-        swift_testing.cmake_options.define('CMAKE_Swift_COMPILER_FORCED', 'TRUE')
-        swift_testing.cmake_options.define('CMAKE_CXX_COMPILER_FORCED', 'TRUE')
+            'CMAKE_Swift_COMPILATION_MODE', 'wholemodule')
+        swift_testing.cmake_options.define('SwiftTesting_MACRO', 'NO')
 
-        swift_testing.build('wasi-wasm32')
+        swift_testing.build_with_cmake([], self.args.build_variant, [],
+                                       prefer_native_toolchain=not self.args.build_runtime_with_host_compiler,
+                                       ignore_extra_cmake_options=True)
+        dest_dir = self._target_package_path(swift_host_triple)
         with shell.pushd(swift_testing.build_dir):
             shell.call([self.toolchain.cmake, '--install', '.', '--prefix', '/usr'],
                        env={'DESTDIR': dest_dir})
 
-    def _build_target_package(self, swift_host_triple, short_triple,
+    def _build_xctest(self, swift_host_triple, has_pthread, wasi_sysroot):
+        xctest = CMakeProduct(
+            args=self.args,
+            toolchain=self.toolchain,
+            source_dir=os.path.join(
+                os.path.dirname(self.source_dir), 'swift-corelibs-xctest'),
+            build_dir=os.path.join(self.build_dir, 'xctest', swift_host_triple))
+        self._append_platform_cmake_options(
+            xctest.cmake_options, swift_host_triple, has_pthread, wasi_sysroot,
+            extra_swift_flags=[])
+        xctest.cmake_options.define('BUILD_SHARED_LIBS', 'FALSE')
+
+        xctest.build_with_cmake([], self.args.build_variant, [],
+                                prefer_native_toolchain=not self.args.build_runtime_with_host_compiler,
+                                ignore_extra_cmake_options=True)
+        dest_dir = self._target_package_path(swift_host_triple)
+        with shell.pushd(xctest.build_dir):
+            shell.call([self.toolchain.cmake, '--install', '.', '--prefix', '/usr'],
+                       env={'DESTDIR': dest_dir})
+
+    def _build_target_package(self, swift_host_triple, clang_multiarch_triple, has_pthread,
                               stdlib_build_path, llvm_runtime_libs_build_path,
                               wasi_sysroot):
 
@@ -103,37 +242,42 @@ def _build_target_package(self, swift_host_triple, short_triple,
                 shell.call([self.toolchain.cmake, '--install', '.',
                             '--component', 'clang_rt.builtins-wasm32'],
                            env={'DESTDIR': clang_dir})
+
+        self._build_libxml2(swift_host_triple, clang_multiarch_triple, has_pthread, wasi_sysroot)
+        self._build_foundation(swift_host_triple, clang_multiarch_triple, has_pthread, wasi_sysroot)
         # Build swift-testing
-        self._build_swift_testing(swift_host_triple, short_triple, wasi_sysroot)
+        self._build_swift_testing(swift_host_triple, has_pthread, wasi_sysroot)
+        self._build_xctest(swift_host_triple, has_pthread, wasi_sysroot)
 
         return dest_dir
 
     def build(self, host_target):
         build_root = os.path.dirname(self.build_dir)
-        llvm_runtime_libs_build_path = os.path.join(
-            build_root, '%s-%s' % ('wasmllvmruntimelibs', host_target))
 
         target_packages = []
-        # NOTE: We have three types of target triples:
+        # NOTE: We have two types of target triples:
         # 1. swift_host_triple: The triple used by the Swift compiler's '-target' option
         # 2. clang_multiarch_triple: The triple used by Clang to find library
         #    and header paths from the sysroot
         #    https://github.com/llvm/llvm-project/blob/73ef397fcba35b7b4239c00bf3e0b4e689ca0add/clang/lib/Driver/ToolChains/WebAssembly.cpp#L29-L36
-        # 3. short_triple: The triple used by build-script to name the build directory
-        for swift_host_triple, clang_multiarch_triple, short_triple, build_basename in [
-            ('wasm32-unknown-wasi', 'wasm32-wasi', 'wasi-wasm32', 'wasmstdlib'),
-            # TODO: Enable threads stdlib once sdk-generator supports multi-target SDK
-            # ('wasm32-unknown-wasip1-threads', 'wasm32-wasip1-threads',
-            #  'wasip1-threads-wasm32', 'wasmthreadsstdlib'),
+        for swift_host_triple, clang_multiarch_triple, build_basename, build_sdk, has_pthread in [
+            ('wasm32-unknown-wasip1', 'wasm32-wasip1', 'wasmstdlib', True, False),
+            # TODO: Include p1-threads in the Swift SDK once sdk-generator supports multi-target SDK
+            ('wasm32-unknown-wasip1-threads', 'wasm32-wasip1-threads',
+             'wasmthreadsstdlib', False, True),
         ]:
             stdlib_build_path = os.path.join(
                 build_root, '%s-%s' % (build_basename, host_target))
             wasi_sysroot = wasisysroot.WASILibc.sysroot_install_path(
                 build_root, clang_multiarch_triple)
+            llvm_runtime_libs_build_path = os.path.join(
+                build_root, '%s-%s' % ('wasmllvmruntimelibs', host_target),
+                clang_multiarch_triple)
             package_path = self._build_target_package(
-                swift_host_triple, short_triple, stdlib_build_path,
+                swift_host_triple, clang_multiarch_triple, has_pthread, stdlib_build_path,
                 llvm_runtime_libs_build_path, wasi_sysroot)
-            target_packages.append((swift_host_triple, wasi_sysroot, package_path))
+            if build_sdk:
+                target_packages.append((swift_host_triple, wasi_sysroot, package_path))
 
         swiftc_path = os.path.abspath(self.toolchain.swiftc)
         toolchain_path = os.path.dirname(os.path.dirname(swiftc_path))
diff --git a/utils/swift_build_support/swift_build_support/targets.py b/utils/swift_build_support/swift_build_support/targets.py
index 508d6204eaf68..71df457bd7af1 100644
--- a/utils/swift_build_support/swift_build_support/targets.py
+++ b/utils/swift_build_support/swift_build_support/targets.py
@@ -72,7 +72,7 @@ def contains(self, target_name):
                 return True
         return False
 
-    def swift_flags(self, args):
+    def swift_flags(self, args, resource_path=None):
         """
         Swift compiler flags for a platform, useful for cross-compiling
         """
@@ -154,17 +154,21 @@ def uses_host_tests(self):
         """
         return True
 
-    def swift_flags(self, args):
+    def swift_flags(self, args, resource_path=None):
         flags = '-target %s-unknown-linux-android%s ' % (args.android_arch,
                                                          args.android_api_level)
 
-        flags += '-resource-dir %s/swift-%s-%s/lib/swift ' % (
-                 args.build_root, self.name, args.android_arch)
+        if resource_path is not None:
+            flags += '-resource-dir %s ' % (resource_path)
+        else:
+            flags += '-resource-dir %s/swift-%s-%s/lib/swift ' % (
+                     args.build_root, self.name, args.android_arch)
 
         android_toolchain_path = self.ndk_toolchain_path(args)
 
         flags += '-sdk %s/sysroot ' % (android_toolchain_path)
-        flags += '-tools-directory %s/bin' % (android_toolchain_path)
+        flags += '-tools-directory %s/bin ' % (android_toolchain_path)
+        flags += '-Xclang-linker -Wl,-z,max-page-size=16384'
         return flags
 
     def cmake_options(self, args):
@@ -290,7 +294,7 @@ class StdlibDeploymentTarget(object):
         "riscv64",
         "s390x"])
 
-    FreeBSD = Platform("freebsd", archs=["x86_64", "arm64"])
+    FreeBSD = Platform("freebsd", archs=["x86_64", "aarch64"])
 
     LinuxStatic = Platform('linux-static', sdk_name='LINUX_STATIC', archs=[
         'x86_64',
@@ -399,7 +403,7 @@ def host_target():
             if machine == 'amd64':
                 return StdlibDeploymentTarget.FreeBSD.x86_64
             elif machine == 'arm64':
-                return StdlibDeploymentTarget.FreeBSD.arm64
+                return StdlibDeploymentTarget.FreeBSD.aarch64
 
         elif system == 'OpenBSD':
             if machine == 'amd64':
diff --git a/utils/swift_build_support/swift_build_support/toolchain.py b/utils/swift_build_support/swift_build_support/toolchain.py
index 8dadeeb766b7f..88b2bc1d15dc7 100644
--- a/utils/swift_build_support/swift_build_support/toolchain.py
+++ b/utils/swift_build_support/swift_build_support/toolchain.py
@@ -68,8 +68,12 @@ def _getter(self):
 else:
     _register("ranlib", "ranlib")
     _register("ar", "ar")
+_register("llvm_ar", "llvm-ar")
+_register("llvm_nm", "llvm-nm")
+_register("llvm_ranlib", "llvm-ranlib")
 _register("sccache", "sccache")
 _register("swiftc", "swiftc")
+_register("swift_build", "swift-build")
 
 
 class Darwin(Toolchain):
diff --git a/utils/swift_build_support/swift_build_support/utils.py b/utils/swift_build_support/swift_build_support/utils.py
index 8465a44da5707..c82b482e525c5 100644
--- a/utils/swift_build_support/swift_build_support/utils.py
+++ b/utils/swift_build_support/swift_build_support/utils.py
@@ -16,7 +16,7 @@
 import sys
 import time
 
-
+from typing import NoReturn
 from build_swift.build_swift.constants import SWIFT_BUILD_ROOT
 
 
@@ -30,7 +30,7 @@ def fatal_error(message, stream=sys.stderr):
     sys.exit(1)
 
 
-def exit_rejecting_arguments(message, parser=None):
+def exit_rejecting_arguments(message, parser=None) -> NoReturn:
     print(message, file=sys.stderr)
     if parser:
         parser.print_usage(sys.stderr)
@@ -97,12 +97,13 @@ def log_analyzer():
         print("================ \t ==================== \t ===========",
               file=sys.stderr)
         event_row = '{:<17.1%} \t {:<21} \t {}'
-        for build_event in finish_events:
-            duration_percentage = \
-                (float(build_event["duration"]) / float(total_duration))
-            print(event_row.format(duration_percentage,
-                                   build_event["duration"],
-                                   build_event["command"]), file=sys.stderr)
+        if total_duration > 0:
+            for build_event in finish_events:
+                duration_percentage = \
+                    (float(build_event["duration"]) / float(total_duration))
+                print(event_row.format(duration_percentage,
+                                       build_event["duration"],
+                                       build_event["command"]), file=sys.stderr)
 
         hours, remainder = divmod(total_duration, 3600)
         minutes, seconds = divmod(remainder, 60)
diff --git a/utils/swift_build_support/tests/products/test_swift.py b/utils/swift_build_support/tests/products/test_swift.py
index 311794db2f29c..5d4c9def75895 100644
--- a/utils/swift_build_support/tests/products/test_swift.py
+++ b/utils/swift_build_support/tests/products/test_swift.py
@@ -52,6 +52,7 @@ def setUp(self):
             benchmark_num_o_iterations=3,
             disable_guaranteed_normal_arguments=True,
             force_optimized_typechecker=False,
+            extra_swift_cmake_options=["-DHELLO=YES"],
             enable_stdlibcore_exclusivity_checking=False,
             enable_experimental_differentiable_programming=False,
             enable_experimental_concurrency=False,
@@ -73,7 +74,12 @@ def setUp(self):
             build_swift_private_stdlib=True,
             swift_tools_ld64_lto_codegen_only_for_supporting_targets=False,
             build_stdlib_docs=False,
-            enable_new_runtime_build=False)
+            enable_new_runtime_build=False,
+            darwin_test_deployment_version_osx="10.9",
+            darwin_test_deployment_version_ios="15.0",
+            darwin_test_deployment_version_tvos="14.0",
+            darwin_test_deployment_version_watchos="6.0",
+            darwin_test_deployment_version_xros="1.0")
 
         # Setup shell
         shell.dry_run = True
@@ -125,6 +131,12 @@ def test_by_default_no_cmake_options(self):
             '-USWIFT_DEBUGINFO_NON_LTO_ARGS',
             '-DSWIFT_STDLIB_BUILD_SYMBOL_GRAPHS:BOOL=FALSE',
             '-DSWIFT_ENABLE_NEW_RUNTIME_BUILD:BOOL=FALSE',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX:STRING=10.9',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS:STRING=15.0',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS:STRING=14.0',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS:STRING=6.0',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS:STRING=1.0',
+            '-DHELLO=YES',
         ]
         self.assertEqual(set(swift.cmake_options), set(expected))
 
@@ -161,6 +173,12 @@ def test_swift_runtime_tsan(self):
             '-USWIFT_DEBUGINFO_NON_LTO_ARGS',
             '-DSWIFT_STDLIB_BUILD_SYMBOL_GRAPHS:BOOL=FALSE',
             '-DSWIFT_ENABLE_NEW_RUNTIME_BUILD:BOOL=FALSE',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_OSX:STRING=10.9',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_IOS:STRING=15.0',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_TVOS:STRING=14.0',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_WATCHOS:STRING=6.0',
+            '-DSWIFT_DARWIN_TEST_DEPLOYMENT_VERSION_XROS:STRING=1.0',
+            '-DHELLO=YES',
         ]
         self.assertEqual(set(swift.cmake_options), set(flags_set))
 
diff --git a/utils/swift_build_support/tests/test_toolchain.py b/utils/swift_build_support/tests/test_toolchain.py
index 34470d578aaa5..e2dc6f743225a 100644
--- a/utils/swift_build_support/tests/test_toolchain.py
+++ b/utils/swift_build_support/tests/test_toolchain.py
@@ -53,9 +53,8 @@ def test_misc_tools(self):
         tc = host_toolchain()
 
         # CMake
-        self.assertIsNotNone(tc.cmake)
-        self.assertTrue(
-            os.path.basename(tc.cmake).startswith('cmake'))
+        self.assertTrue(tc.cmake is None or
+                        os.path.basename(tc.cmake).startswith('cmake'))
 
         # Ninja
         self.assertTrue(tc.ninja is None or
diff --git a/utils/swift_snapshot_tool/Package.resolved b/utils/swift_snapshot_tool/Package.resolved
new file mode 100644
index 0000000000000..3dcc511149ffb
--- /dev/null
+++ b/utils/swift_snapshot_tool/Package.resolved
@@ -0,0 +1,15 @@
+{
+  "originHash" : "80ba966d30db4d84324c2bda4f2b419b9e6fe208fa1f70080f74c7aa3d432a49",
+  "pins" : [
+    {
+      "identity" : "swift-argument-parser",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-argument-parser",
+      "state" : {
+        "revision" : "41982a3656a71c768319979febd796c6fd111d5c",
+        "version" : "1.5.0"
+      }
+    }
+  ],
+  "version" : 3
+}
diff --git a/utils/swift_snapshot_tool/README.md b/utils/swift_snapshot_tool/README.md
index 50c693e036adf..05b133b66a42f 100644
--- a/utils/swift_snapshot_tool/README.md
+++ b/utils/swift_snapshot_tool/README.md
@@ -9,8 +9,8 @@ Used to list and bisect nightly snapshots off of swift.org.
 
 ```
 # xcrun swift run swift_snapshot_tool list
-[INFO] Starting to download snapshot information from github. 
-[INFO] Finished downloading snapshot information from github. 
+[INFO] Starting to download snapshot information from github.
+[INFO] Finished downloading snapshot information from github.
 0 swift-DEVELOPMENT-SNAPSHOT-2024-09-06-a
 1 swift-DEVELOPMENT-SNAPSHOT-2024-09-05-a
 2 swift-DEVELOPMENT-SNAPSHOT-2024-09-04-a
@@ -23,11 +23,51 @@ value is at. This allows for one to get a sense of the range of time in between
 two bisect numbers since one can look at the range in between them and how time
 varies.
 
+One can specify a branch of snapshots to list. By default uses
+--development. Also supports the options --release_5_0, --release_6_0,
+--release_6_2.
+
+## Run
+
+```
+xcrun swift run swift_snapshot_tool run --script $SCRIPT_NAME \
+  --date YYYY-MM-DD [--invert] [--workspace $DIR_TO_DOWNLOAD_TOOLCHAINS]
+```
+
+run success is defined by `$SCRIPT_NAME` returning 0 as an exit code. All other
+exit codes are considered a failure.
+
+This command is meant to help one figure out where to start bisecting.
+
+Options:
+
+- workspace: This is the place where we will download toolchains to. Defaults to
+  `/tmp/swift_snapshot_tool_workspace_v1`. We suggest that you use an external
+  hard drive or a specified place so that one does not have to redownload
+  toolchains in between system restarts.
+
+- script: This is the script that should be run. We pass in the environment
+  variables `SWIFT_EXEC`, `SWIFT_FRONTEND`, and `SWIFT_LIBRARY_PATH` to the
+  script. If the script returns a zero exit code then the run is considered a
+  succeess. If the script returns a non-zero exit code, then the run is
+  considered a failure.
+
+- date: A date in the form YYYY-MM-DD. If a snapshot at date does not exist, we
+  choose the first snapshot before that date.
+
+- invert: This causes test.sh's result to be inverted. This allows one to bisect
+  backwards from a good state to a bad state. This is useful to determine when
+  an error was fixed.
+
+- branch: This controls the specific branch of snapshots that are downloaded. By
+  default uses --development. Also supports the options --release_5_0,
+  --release_6_0, --release_6_2.
+
 ## Bisect
 
 ```
-xcrun swift run swift_snapshot_tool bisect --script $SCRIPT_NAME --workspace $DIR_TO_DOWNLOAD_TOOLCHAINS \
-   --good-tag $OLDER_TAG_NAME_THAT_PASSES --bad-tag $NEWER_TAG_NAME_THAT_FAILS
+xcrun swift run swift_snapshot_tool bisect --script $SCRIPT_NAME --old-date YYYY_MM_DD \
+   [--new-date YYYY_MM_DD] [--workspace $DIR_TO_DOWNLOAD_TOOLCHAINS]
 ```
 
 bisect success is defined by `$SCRIPT_NAME` returning 0 as an exit code. All
@@ -36,22 +76,40 @@ other exit codes are considered a failure.
 Options:
 
 - workspace: This is the place where we will download toolchains to. Defaults to
-  `/tmp/swift_snapshot_tool_workspace_v1`
+  `/tmp/swift_snapshot_tool_workspace_v1`. We suggest that you use an external
+  hard drive or a specified place so that one does not have to redownload
+  toolchains in between system restarts.
 
 - script: This is the script that should be run. We pass in the environment
-  variables `SWIFT_EXEC` and `SWIFT_FRONTEND` to the subscript. If the script
-  returns a zero exit code then the run is considered a succeess. If the script
-  returns a non-zero exit code, then the run is considered a failure.
+  variables `SWIFT_EXEC`, `SWIFT_FRONTEND`, `SWIFT_LIBRARY_PATH` to the
+  script. If the script returns a zero exit code then the run is considered a
+  succeess. If the script returns a non-zero exit code, then the run is
+  considered a failure.
 
-- good_tag: This is the older tag and is assumed to succeed by returning a zero
-  exit code.
+- old-date: Date in the form of YYYY-MM-DD. This is assumed to succeed by
+  returning a zero exit code. If a snapshot does not exist at this date, the
+  tool will choose the first snapshot before the date.
 
-- bad_tag: This is the newer tag and is assumed to fail by returning a non-zero
-  exit code.
+- new-date: Date in the form of YYYY-MM-DD. This is assumed to fail by returning
+  a non-zero exit code. If a snapshot does not exist at this date, the tool will
+  choose the first snapshot before the date.
 
 - invert: This causes test.sh's result to be inverted. This allows one to bisect
   backwards from a good state to a bad state. This is useful to determine when
   an error was fixed.
 
 - branch: This controls the specific branch of snapshots that are downloaded. By
-  default uses development. Also supports the options 5.0 and 6.0.
+  default uses --development. Also supports the options --release_5_0,
+  --release_6_0, --release_6_2.
+
+# FAQ and Helpful Tips
+
+## Bisecting against examples using Swift Testing
+
+Swift Testing is not stored in the normal place in a toolchain. To test against
+such an example that uses swift testing pass into ones script the following -I
+command:
+
+```
+xcrun ${SWIFTC}  "${@:1}" -o binary -parse-as-library -I ${SWIFT_LIBRARY_PATH}/testing
+```
diff --git a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/bisect_toolchains.swift b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/bisect_toolchains.swift
index 90808c4dab20e..8f94525df79db 100644
--- a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/bisect_toolchains.swift
+++ b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/bisect_toolchains.swift
@@ -17,8 +17,10 @@ struct BisectToolchains: AsyncParsableCommand {
   static let configuration = CommandConfiguration(
     commandName: "bisect",
     discussion: """
-      Bisects on exit status of attached script. Passes in name of swift as the
-      environment variables \(environmentVariables).
+      Bisects on swift snapshots downloaded from swift.org via an exit status of
+      a script. Script is passed paths into the downloaded snapshot via
+      environment variables and is expected to compile and or run swift programs
+      using the snapshot artifacts.
       """)
 
   @Flag var platform: Platform = .osx
@@ -34,13 +36,16 @@ struct BisectToolchains: AsyncParsableCommand {
 
   @Option(
     help: """
-      The script that should be run. It runs a specific swift compilation and
-      optionally program using the passed in environment variables
-      \(environmentVariables)
+      The script that should be run. It should run a specific swift compilation and
+      or program. Paths into the snapshots are passed in via the environment variables \(environmentVariables).
       """)
   var script: String
 
-  @Option(help: "Oldest Date. Expected to Pass. We use the first snapshot produced before the given date")
+  @Option(help:
+            """
+            Expected to Pass. We use the first snapshot produced before the
+            given date if a snapshot at this specific date does not exist
+            """)
   var oldDate: String
 
   var oldDateAsDate: Date {
@@ -54,9 +59,10 @@ struct BisectToolchains: AsyncParsableCommand {
   }
 
   @Option(help: """
-    Newest Date. Expected to fail. If not set, use newest snapshot. We use the
-    first snapshot after new date
-    """)
+            Expected to fail. If not set, defaults to use newest snapshot. If a
+            date is specified and a snapshot does not exist for that date, the
+            first snapshot before the specified date is used.
+            """)
   var newDate: String?
 
   var newDateAsDate: Date? {
@@ -95,7 +101,7 @@ struct BisectToolchains: AsyncParsableCommand {
     // just say 50 toolchains ago. To get a few weeks worth. This is easier than
     // writing dates a lot.
     let oldDateAsDate = self.oldDateAsDate
-    guard let goodTagIndex = tags.firstIndex(where: { $0.tag.date(branch: self.branch) < oldDateAsDate }) else {
+    guard let goodTagIndex = tags.firstIndex(where: { $0.tag.date(branch: self.branch) <= oldDateAsDate }) else {
       log("Failed to find tag with date: \(oldDateAsDate)")
       fatalError()
     }
diff --git a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/download_toolchain.swift b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/download_toolchain.swift
index 8b5a2010658b8..5ae54efb77579 100644
--- a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/download_toolchain.swift
+++ b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/download_toolchain.swift
@@ -128,7 +128,7 @@ func downloadToolchainAndRunTest(
   let fileType = platform.fileType
   let toolchainType = platform.toolchainType
 
-  let realBranch = branch != .development ? "swift-\(branch)-branch" : branch.rawValue
+  let realBranch = branch.urlBranchName
   let toolchainDir = "\(workspace)/\(tag.name)-\(platform)"
   let downloadPath = URL(fileURLWithPath: "\(workspace)/\(tag.name)-\(platform).\(fileType)")
   if !fileExists(toolchainDir) {
diff --git a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/get_tags.swift b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/get_tags.swift
index 6aaf9b2872e98..b0e33460e98cb 100644
--- a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/get_tags.swift
+++ b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/get_tags.swift
@@ -27,18 +27,23 @@ struct Tag: Decodable {
     ref.dropFirst(10)
   }
 
-  func dateString(_ branch: Branch) -> Substring {
-    // FIXME: If we ever actually use interesting a-b builds, we should capture this information
-    // would be better to do it sooner than later.
-    return name.dropFirst("swift-".count + branch.rawValue.count + "-SNAPSHOT-".count).dropLast(2)
-  }
-
   func date(branch: Branch) -> Date {
-    // TODO: I think that d might be a class... if so, we really want to memoize
-    // this.
     let d = DateFormatter()
     d.dateFormat = "yyyy-MM-dd"
-    return d.date(from: String(dateString(branch)))!
+    // TODO: Change top use swift regexp
+    let pattern = "swift-.*DEVELOPMENT-SNAPSHOT-(\\d+-\\d+-\\d+)"
+    do {
+      let regex = try NSRegularExpression(pattern: pattern, options: .caseInsensitive)
+      guard let match = regex.firstMatch(in: String(name),
+                                         options: [],
+                                         range: NSRange(location: 0, length: name.utf16.count)) else {
+        fatalError("Failed to find match!")
+      }
+      let str = String((name as NSString).substring(with: match.range(at: 1)))
+      return d.date(from: str)!
+    } catch let error as NSError {
+      fatalError("Error creating NSRegularExpression: \(error)")
+    }
   }
 }
 
@@ -77,12 +82,10 @@ func getTagsFromSwiftRepo(branch: Branch, dryRun: Bool = false) async throws ->
   let allTags = try! decoder.decode([Tag].self, from: await data)
   log("[INFO] Finished downloading snapshot information from github.")
 
-  let snapshotTagPrefix = "swift-\(branch.rawValue.uppercased())"
-
   // Then filter the tags to just include the specific snapshot branch
   // prefix. Add the branch to an aggregate BranchTag.
   var filteredTags: [BranchTag] = allTags.filter {
-    $0.name.starts(with: snapshotTagPrefix)
+    $0.name.starts(with: branch.tagPrefix)
   }.map {
     BranchTag(tag: $0, branch: branch)
   }
diff --git a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/github_repository.swift b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/github_repository.swift
index 70957c1f48434..0db7f33c7027c 100644
--- a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/github_repository.swift
+++ b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/github_repository.swift
@@ -23,8 +23,8 @@ enum Platform: String, EnumerableFlag {
     case .osx:
       return "pkg"
     case .ubuntu1404,
-      .ubuntu1604,
-      .ubuntu1804:
+         .ubuntu1604,
+         .ubuntu1804:
       return "tar.gz"
     }
   }
@@ -34,8 +34,8 @@ enum Platform: String, EnumerableFlag {
     case .osx:
       return "xcode"
     case .ubuntu1404,
-      .ubuntu1604,
-      .ubuntu1804:
+         .ubuntu1604,
+         .ubuntu1804:
       return self.rawValue
     }
   }
@@ -43,6 +43,25 @@ enum Platform: String, EnumerableFlag {
 
 enum Branch: String, EnumerableFlag {
   case development
-  case release50 = "5.0"
-  case release60 = "6.0"
+  case release_5_0 = "5.0"
+  case release_6_0 = "6.0"
+  case release_6_2 = "6.2"
+
+  var tagPrefix: String {
+    switch self {
+    case .development:
+      "swift-\(rawValue.uppercased())"
+    default:
+      "swift-\(rawValue.uppercased())-DEVELOPMENT"
+    }
+  }
+
+  var urlBranchName: String {
+    switch self {
+    case .development:
+      return self.rawValue
+    default:
+      return "swift-\(self.rawValue)-branch"
+    }
+  }
 }
diff --git a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/list_snapshots.swift b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/list_snapshots.swift
index de0f771fa2e9f..54eb714b9bd79 100644
--- a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/list_snapshots.swift
+++ b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/list_snapshots.swift
@@ -14,7 +14,12 @@ import ArgumentParser
 
 struct ListSnapshots: AsyncParsableCommand {
   static let configuration = CommandConfiguration(
-    commandName: "list")
+    commandName: "list",
+    discussion: """
+      Downloads the current list of available snapshots from swift.org and
+      outputs the snapshots to stdout. Useful to see what snapshots are
+      available.
+      """)
 
   @Flag var platform: Platform = .osx
 
diff --git a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/run_toolchain.swift b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/run_toolchain.swift
index 71c412855ecef..8c775477d8690 100644
--- a/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/run_toolchain.swift
+++ b/utils/swift_snapshot_tool/Sources/swift_snapshot_tool/run_toolchain.swift
@@ -17,8 +17,11 @@ struct RunToolchains: AsyncParsableCommand {
   static let configuration = CommandConfiguration(
     commandName: "run",
     discussion: """
-    Run a toolchain like bisect would. Passed the environment variables:
-    \(environmentVariables)
+      Run and determine success/failure of a script against a specified snapshot
+      like the bisect command would. Used to determine the start/end bisect
+      dates to pass to the bisect command. The script is passed paths into the
+      downloaded snapshot via environment variables and is expected to compile
+      and or run swift programs using the snapshot artifacts.
     """)
 
   @Flag var platform: Platform = .osx
@@ -34,13 +37,23 @@ struct RunToolchains: AsyncParsableCommand {
 
   @Option(
     help: """
-      The script that should be run. The environment variable
-      SWIFT_EXEC is used by the script to know where swift-frontend is
+      The script that should be run. It should run a specific swift compilation and
+      or program. Paths into the snapshots are passed in via the environment variables \(environmentVariables).
       """)
   var script: String
 
-  @Option(help: "Snapshot tag to run the test for")
-  var tag: String
+  @Option(help: "Date. We use the first snapshot produced before the given date")
+  var date: String
+
+  var dateAsDate: Date {
+    let d = DateFormatter()
+    d.dateFormat = "yyyy-MM-dd"
+    guard let result = d.date(from: date) else {
+      log("Improperly formatted date: \(date)! Expected format: yyyy_MM_dd.")
+      fatalError()
+    }
+    return result
+  }
 
   @Flag(help: "Invert the test so that we assume the newest succeeds")
   var invert = false
@@ -69,8 +82,9 @@ struct RunToolchains: AsyncParsableCommand {
     // Load our tags from swift's github repo
     let tags = try! await getTagsFromSwiftRepo(branch: branch)
 
-    guard var tagIndex = tags.firstIndex(where: { $0.tag.name == self.tag }) else {
-      log("Failed to find tag: \(self.tag)")
+    let date = self.dateAsDate
+    guard var tagIndex = tags.firstIndex(where: { $0.tag.date(branch: self.branch) <= date }) else {
+      log("Failed to find tag with date: \(date)")
       fatalError()
     }
 
diff --git a/utils/toolchain-installer b/utils/toolchain-installer
index 28fc10fcd902d..4801fac9aee4f 100755
--- a/utils/toolchain-installer
+++ b/utils/toolchain-installer
@@ -18,7 +18,8 @@ DARWIN_INSTALLER_PACKAGE=$4
 DARWIN_TOOLCHAIN_INSTALL_LOCATION=$5
 DARWIN_TOOLCHAIN_VERSION=$6
 DARWIN_SCRIPTS=$7
+DARWIN_DEPLOYMENT_VERSION_OSX=$8
 
 pkgbuild --root "${TOOLCHAIN_PREFIX}" --install-location "${DARWIN_TOOLCHAIN_INSTALL_LOCATION}" "${DARWIN_INSTALLER_PACKAGE}" \
          --version "${DARWIN_TOOLCHAIN_VERSION}" --identifier "${DARWIN_BUNDLE_IDENTIFIER}" --sign "${DARWIN_INSTALLER_CERT}" \
-         --scripts "${DARWIN_SCRIPTS}"
+         --scripts "${DARWIN_SCRIPTS}" --min-os-version "${DARWIN_DEPLOYMENT_VERSION_OSX}"
diff --git a/utils/update_checkout/tests/scheme_mock.py b/utils/update_checkout/tests/scheme_mock.py
index 4f788041c0d94..e703b995e6e29 100644
--- a/utils/update_checkout/tests/scheme_mock.py
+++ b/utils/update_checkout/tests/scheme_mock.py
@@ -62,6 +62,21 @@
     }
 }
 
+MOCK_ADDITIONAL_SCHEME = {
+    'branch-schemes': {
+        'extra': {
+            'aliases': ['extra'],
+            'repos': {
+                # Spell this differently just to make it distinguishable in
+                # test output, even though we only have one branch.
+                # TODO: Support multiple test branches in the repo instead.
+                'repo1': 'refs/heads/main',
+                'repo2': 'refs/heads/main',
+            }
+        }
+    }
+}
+
 
 class CallQuietlyException(Exception):
     def __init__(self, command, returncode, output):
@@ -78,7 +93,7 @@ def __str__(self):
 def call_quietly(*args, **kwargs):
     kwargs['stderr'] = subprocess.STDOUT
     try:
-        subprocess.check_output(*args, **kwargs)
+        return subprocess.check_output(*args, **kwargs)
     except subprocess.CalledProcessError as e:
         raise CallQuietlyException(command=e.cmd, returncode=e.returncode,
                                    output=e.stdout) from e
@@ -97,6 +112,10 @@ def get_config_path(base_dir):
     return os.path.join(base_dir, 'test-config.json')
 
 
+def get_additional_config_path(base_dir):
+    return os.path.join(base_dir, 'test-additional-config.json')
+
+
 def setup_mock_remote(base_dir, base_config):
     create_dir(base_dir)
 
@@ -118,9 +137,11 @@ def setup_mock_remote(base_dir, base_config):
         call_quietly(['git', 'symbolic-ref', 'HEAD', 'refs/heads/main'],
                      cwd=remote_repo_path)
         call_quietly(['git', 'clone', '-l', remote_repo_path, local_repo_path])
-        call_quietly(['git', 'config', 'user.name', 'swift_test'],
+        call_quietly(['git', 'config', '--local', 'user.name', 'swift_test'],
                      cwd=local_repo_path)
-        call_quietly(['git', 'config', 'user.email', 'no-reply@swift.org'],
+        call_quietly(['git', 'config', '--local', 'user.email', 'no-reply@swift.org'],
+                     cwd=local_repo_path)
+        call_quietly(['git', 'config', '--local', 'commit.gpgsign', 'false'],
                      cwd=local_repo_path)
         call_quietly(['git', 'symbolic-ref', 'HEAD', 'refs/heads/main'],
                      cwd=local_repo_path)
@@ -140,15 +161,19 @@ def setup_mock_remote(base_dir, base_config):
     with open(get_config_path(base_dir), 'w') as f:
         json.dump(base_config, f)
 
+    with open(get_additional_config_path(base_dir), 'w') as f:
+        json.dump(MOCK_ADDITIONAL_SCHEME, f)
+
     return (LOCAL_PATH, REMOTE_PATH)
 
 
 BASEDIR_ENV_VAR = 'UPDATECHECKOUT_TEST_WORKSPACE_DIR'
 CURRENT_FILE_DIR = os.path.dirname(os.path.abspath(__file__))
+UPDATE_CHECKOUT_EXECUTABLE = 'update-checkout.cmd' if os.name == 'nt' else 'update-checkout'
 UPDATE_CHECKOUT_PATH = os.path.abspath(os.path.join(CURRENT_FILE_DIR,
                                                     os.path.pardir,
                                                     os.path.pardir,
-                                                    'update-checkout'))
+                                                    UPDATE_CHECKOUT_EXECUTABLE))
 
 
 class SchemeMockTestCase(unittest.TestCase):
@@ -162,6 +187,7 @@ def __init__(self, *args, **kwargs):
             raise RuntimeError('Misconfigured test suite! Environment '
                                'variable %s must be set!' % BASEDIR_ENV_VAR)
         self.config_path = get_config_path(self.workspace)
+        self.additional_config_path = get_additional_config_path(self.workspace)
         self.update_checkout_path = UPDATE_CHECKOUT_PATH
         if not os.access(self.update_checkout_path, os.X_OK):
             raise RuntimeError('Error! Could not find executable '
@@ -180,7 +206,7 @@ def tearDown(self):
 
     def call(self, *args, **kwargs):
         kwargs['cwd'] = self.source_root
-        call_quietly(*args, **kwargs)
+        return call_quietly(*args, **kwargs)
 
     def get_all_repos(self):
         return list(self.config["repos"].keys())
diff --git a/utils/update_checkout/tests/test_clone.py b/utils/update_checkout/tests/test_clone.py
index 49b9fe948c6fb..4f4b3d8f6b18b 100644
--- a/utils/update_checkout/tests/test_clone.py
+++ b/utils/update_checkout/tests/test_clone.py
@@ -13,6 +13,7 @@
 import os
 
 from . import scheme_mock
+from unittest import mock
 
 
 class CloneTestCase(scheme_mock.SchemeMockTestCase):
@@ -30,6 +31,32 @@ def test_simple_clone(self):
             repo_path = os.path.join(self.source_root, repo)
             self.assertTrue(os.path.isdir(repo_path))
 
+    def test_clone_with_additional_scheme(self):
+        output = self.call([self.update_checkout_path,
+                            '--config', self.config_path,
+                            '--config', self.additional_config_path,
+                            '--source-root', self.source_root,
+                            '--clone',
+                            '--scheme', 'extra',
+                            '--verbose'])
+
+        # Test that we're actually checking out the 'extra' scheme based on the output
+        self.assertIn(b"git checkout refs/heads/main", output)
+
+    def test_manager_not_called_on_long_socket(self):
+        fake_tmpdir = '/tmp/very/' + '/long' * 20 + '/tmp'
+
+        with mock.patch('tempfile.gettempdir', return_value=fake_tmpdir), \
+            mock.patch('multiprocessing.Manager') as mock_manager:
+
+            self.call([self.update_checkout_path,
+                    '--config', self.config_path,
+                    '--source-root', self.source_root,
+                    '--clone'])
+            # Ensure that we do not try to create a Manager when the tempdir
+            # is too long.
+            mock_manager.assert_not_called()
+
 
 class SchemeWithMissingRepoTestCase(scheme_mock.SchemeMockTestCase):
     def __init__(self, *args, **kwargs):
diff --git a/utils/update_checkout/tests/test_dump.py b/utils/update_checkout/tests/test_dump.py
index e102071f812e0..87cb76e81d4d8 100644
--- a/utils/update_checkout/tests/test_dump.py
+++ b/utils/update_checkout/tests/test_dump.py
@@ -10,6 +10,8 @@
 #
 # ===----------------------------------------------------------------------===#
 
+import json
+
 from . import scheme_mock
 
 
@@ -25,9 +27,16 @@ def test_dump_hashes_json(self):
                    '--source-root', self.source_root,
                    '--clone'])
 
-        # Then dump the hashes. Just make sure we don't crash. We should test
-        # the output as well. But we should never crash.
-        self.call([self.update_checkout_path,
-                   '--config', self.config_path,
-                   '--source-root', self.source_root,
-                   '--dump-hashes'])
+        # Then dump the hashes.
+        output = self.call([self.update_checkout_path,
+                            '--config', self.config_path,
+                            '--source-root', self.source_root,
+                            '--dump-hashes'])
+        # The output should be valid JSON
+        result = json.loads(output)
+
+        # And it should have some basic properties we expect from this JSON
+        self.assertIn("https-clone-pattern", result)
+        self.assertEqual(result["repos"], scheme_mock.MOCK_CONFIG["repos"])
+        self.assertEqual(result["ssh-clone-pattern"], "DO_NOT_USE")
+        self.assertSetEqual(set(result["branch-schemes"].keys()), {"repro"})
diff --git a/utils/update_checkout/tests/test_locked_repository.py b/utils/update_checkout/tests/test_locked_repository.py
new file mode 100644
index 0000000000000..e81166b533c79
--- /dev/null
+++ b/utils/update_checkout/tests/test_locked_repository.py
@@ -0,0 +1,109 @@
+import unittest
+from unittest.mock import patch
+
+from update_checkout.update_checkout import UpdateArguments, _is_any_repository_locked
+
+
+def _update_arguments_with_fake_path(repo_name: str, path: str) -> UpdateArguments:
+    return UpdateArguments(
+        repo_name=repo_name,
+        source_root=path,
+        config={},
+        scheme_name="",
+        scheme_map=None,
+        tag="",
+        timestamp=None,
+        reset_to_remote=False,
+        clean=False,
+        stash=False,
+        cross_repos_pr=False,
+        output_prefix="",
+        verbose=False,
+    )
+
+
+class TestIsAnyRepositoryLocked(unittest.TestCase):
+    @patch("os.path.exists")
+    @patch("os.path.isdir")
+    @patch("os.listdir")
+    def test_repository_with_lock_file(self, mock_listdir, mock_isdir, mock_exists):
+        pool_args = [
+            _update_arguments_with_fake_path("repo1", "/fake_path"),
+            _update_arguments_with_fake_path("repo2", "/fake_path"),
+        ]
+
+        def listdir_side_effect(path):
+            if "repo1" in path:
+                return ["index.lock", "config"]
+            elif "repo2" in path:
+                return ["HEAD", "config"]
+            return []
+
+        mock_exists.return_value = True
+        mock_isdir.return_value = True
+        mock_listdir.side_effect = listdir_side_effect
+
+        result = _is_any_repository_locked(pool_args)
+        self.assertEqual(result, {"repo1"})
+
+    @patch("os.path.exists")
+    @patch("os.path.isdir")
+    @patch("os.listdir")
+    def test_repository_without_git_dir(self, mock_listdir, mock_isdir, mock_exists):
+        pool_args = [
+            _update_arguments_with_fake_path("repo1", "/fake_path"),
+        ]
+
+        mock_exists.return_value = False
+        mock_isdir.return_value = False
+        mock_listdir.return_value = []
+
+        result = _is_any_repository_locked(pool_args)
+        self.assertEqual(result, set())
+
+    @patch("os.path.exists")
+    @patch("os.path.isdir")
+    @patch("os.listdir")
+    def test_repository_with_git_file(self, mock_listdir, mock_isdir, mock_exists):
+        pool_args = [
+            _update_arguments_with_fake_path("repo1", "/fake_path"),
+        ]
+
+        mock_exists.return_value = True
+        mock_isdir.return_value = False
+        mock_listdir.return_value = []
+
+        result = _is_any_repository_locked(pool_args)
+        self.assertEqual(result, set())
+
+    @patch("os.path.exists")
+    @patch("os.path.isdir")
+    @patch("os.listdir")
+    def test_repository_with_multiple_lock_files(
+        self, mock_listdir, mock_isdir, mock_exists
+    ):
+        pool_args = [
+            _update_arguments_with_fake_path("repo1", "/fake_path"),
+        ]
+
+        mock_exists.return_value = True
+        mock_isdir.return_value = True
+        mock_listdir.return_value = ["index.lock", "merge.lock", "HEAD"]
+
+        result = _is_any_repository_locked(pool_args)
+        self.assertEqual(result, {"repo1"})
+
+    @patch("os.path.exists")
+    @patch("os.path.isdir")
+    @patch("os.listdir")
+    def test_repository_with_no_lock_files(self, mock_listdir, mock_isdir, mock_exists):
+        pool_args = [
+            _update_arguments_with_fake_path("repo1", "/fake_path"),
+        ]
+
+        mock_exists.return_value = True
+        mock_isdir.return_value = True
+        mock_listdir.return_value = ["HEAD", "config", "logs"]
+
+        result = _is_any_repository_locked(pool_args)
+        self.assertEqual(result, set())
diff --git a/utils/update_checkout/tests/test_merge_config.py b/utils/update_checkout/tests/test_merge_config.py
new file mode 100644
index 0000000000000..4963f12b07946
--- /dev/null
+++ b/utils/update_checkout/tests/test_merge_config.py
@@ -0,0 +1,75 @@
+# ===--- test_merge_config.py ---------------------------------------------===#
+#
+#  This source file is part of the Swift.org open source project
+#
+#  Copyright (c) 2025 Apple Inc. and the Swift project authors
+#  Licensed under Apache License v2.0 with Runtime Library Exception
+#
+#  See https:#swift.org/LICENSE.txt for license information
+#  See https:#swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+#
+# ===----------------------------------------------------------------------===#
+
+import unittest
+
+from update_checkout.update_checkout import merge_config, merge_no_duplicates
+
+
+class MergeTestCase(unittest.TestCase):
+    def test_no_duplicates(self):
+        self.assertEqual(merge_no_duplicates({}, {}), {})
+        self.assertEqual(merge_no_duplicates({"a": 1}, {"b": 2}), {"a": 1, "b": 2})
+        with self.assertRaises(ValueError):
+            merge_no_duplicates({"a": 1, "b": 2}, {"b": 3})
+
+    def test_merge_config(self):
+        default_config = {
+            "ssh-clone-pattern": "git@1",
+            "https-clone-pattern": "https://1",
+            "repos": {
+                "swift": {"remote": {"id": "swiftlang/swift"}},
+                "llvm-project": {"remote": {"id": "swiftlang/llvm-project"}},
+            },
+            "default-branch-scheme": "main",
+            "branch-schemes": {
+                "main": {
+                    "aliases": ["swift/main", "main", "stable/20240723"],
+                },
+            },
+        }
+
+        self.assertEqual(merge_config(default_config, {
+            "note": "this is machine generated or something",
+            "ssh-clone-pattern": "git@2",
+            "repos": {
+                "llvm-project": {"remote": {"id": "blah/llvm-project"}},
+                "swift-syntax": {"remote": {"id": "swiftlang/swift-syntax"}},
+            },
+            "default-branch-scheme": "bonus",
+            "branch-schemes": {
+                "bonus": {
+                    "aliases": ["bonus", "also-bonus"],
+                },
+            },
+        }), {
+            "ssh-clone-pattern": "git@2",
+            "https-clone-pattern": "https://1",
+            "repos": {
+                "swift": {"remote": {"id": "swiftlang/swift"}},
+                "llvm-project": {"remote": {"id": "blah/llvm-project"}},
+                "swift-syntax": {"remote": {"id": "swiftlang/swift-syntax"}},
+            },
+            "default-branch-scheme": "bonus",
+            "branch-schemes": {
+                "main": {
+                    "aliases": ["swift/main", "main", "stable/20240723"],
+                },
+                "bonus": {
+                    "aliases": ["bonus", "also-bonus"],
+                },
+            },
+            "note": "this is machine generated or something",
+        })
+
+        with self.assertRaises(ValueError):
+            merge_config(default_config, default_config)
diff --git a/utils/update_checkout/update-checkout-config.json b/utils/update_checkout/update-checkout-config.json
index ffce049ea3147..838fe3286e031 100644
--- a/utils/update_checkout/update-checkout-config.json
+++ b/utils/update_checkout/update-checkout-config.json
@@ -15,7 +15,7 @@
         "swift-async-algorithms": {
             "remote": { "id": "apple/swift-async-algorithms" } },
         "swift-atomics": {
-            "remote": { "id": "apple/swift-atomics" } },       
+            "remote": { "id": "apple/swift-atomics" } },
         "swift-collections": {
             "remote": { "id": "apple/swift-collections" } },
         "swift-crypto": {
@@ -29,7 +29,7 @@
         "swift-log": {
             "remote": { "id": "apple/swift-log" } },
         "swift-numerics": {
-            "remote": { "id": "apple/swift-numerics" } },        
+            "remote": { "id": "apple/swift-numerics" } },
         "swift-toolchain-sqlite": {
             "remote": { "id": "swiftlang/swift-toolchain-sqlite" } },
         "swift-tools-support-core": {
@@ -47,9 +47,9 @@
         "swift-corelibs-xctest": {
             "remote": { "id": "swiftlang/swift-corelibs-xctest" } },
         "swift-corelibs-foundation": {
-            "remote": { "id": "swiftlang/swift-corelibs-foundation" } },  
+            "remote": { "id": "swiftlang/swift-corelibs-foundation" } },
         "swift-foundation-icu": {
-            "remote": { "id": "swiftlang/swift-foundation-icu" } },  
+            "remote": { "id": "swiftlang/swift-foundation-icu" } },
         "swift-foundation": {
             "remote": { "id": "swiftlang/swift-foundation" } },
         "swift-corelibs-libdispatch": {
@@ -67,7 +67,7 @@
         },
         "cmake": {
             "remote": { "id": "KitWare/CMake" },
-            "platforms": [ "Linux" ]
+            "platforms": [ "Darwin", "Linux" ]
         },
         "swift-cmark-gfm": {
              "remote": { "id": "swiftlang/swift-cmark" } },
@@ -121,34 +121,37 @@
         "mimalloc": {
           "remote": { "id": "microsoft/mimalloc" },
           "platforms": [ "Windows" ]
+        },
+        "swift-subprocess": {
+          "remote": { "id": "swiftlang/swift-subprocess" }
         }
     },
     "default-branch-scheme": "main",
     "branch-schemes": {
         "main": {
-            "aliases": ["swift/main", "main", "stable/20240723"],
+            "aliases": ["swift/main", "main", "stable/21.x"],
             "repos": {
-                "llvm-project": "stable/20240723",
-                "swift-llvm-bindings": "stable/20240723",
+                "llvm-project": "stable/21.x",
+                "swift-llvm-bindings": "stable/21.x",
                 "swift": "main",
                 "cmark": "gfm",
                 "llbuild": "main",
                 "swift-build": "main",
-                "swift-toolchain-sqlite": "1.0.1",
+                "swift-toolchain-sqlite": "1.0.7",
                 "swift-tools-support-core": "main",
                 "swiftpm": "main",
-                "swift-argument-parser": "1.4.0",
+                "swift-argument-parser": "1.5.1",
                 "swift-atomics": "1.2.0",
-                "swift-collections": "1.1.3",
-                "swift-crypto": "3.0.0",
-                "swift-certificates": "1.0.1",
-                "swift-asn1": "1.0.0",
+                "swift-collections": "1.1.6",
+                "swift-crypto": "3.12.5",
+                "swift-certificates": "1.10.1",
+                "swift-asn1": "1.3.2",
                 "swift-async-algorithms": "1.0.1",
                 "swift-driver": "main",
                 "swift-log": "1.5.4",
                 "swift-numerics": "1.0.2",
                 "swift-syntax": "main",
-                "swift-system": "1.4.1",
+                "swift-system": "1.5.0",
                 "swift-stress-tester": "main",
                 "swift-testing": "main",
                 "swift-corelibs-xctest": "main",
@@ -158,7 +161,7 @@
                 "swift-corelibs-libdispatch": "main",
                 "swift-integration-tests": "main",
                 "swift-xcode-playground-support": "main",
-                "ninja": "v1.11.1",
+                "ninja": "v1.13.1",
                 "cmake": "v3.30.2",
                 "indexstore-db": "main",
                 "sourcekit-lsp": "main",
@@ -170,8 +173,119 @@
                 "swift-docc-symbolkit": "main",
                 "swift-markdown": "main",
                 "swift-nio": "2.65.0",
-                "swift-experimental-string-processing": "swift/main",
+                "swift-experimental-string-processing": "main",
                 "swift-sdk-generator": "main",
+                "wasi-libc": "wasi-sdk-27",
+                "wasmkit": "0.1.6",
+                "curl": "curl-8_9_1",
+                "libxml2": "v2.11.5",
+                "zlib": "v1.3.1",
+                "mimalloc": "v3.0.3",
+                "swift-subprocess": "0.1"
+            }
+        },
+        "release/6.2": {
+            "aliases": ["swift/release/6.2", "release/6.2"],
+            "repos": {
+                "llvm-project": "swift/release/6.2",
+                "swift-llvm-bindings": "swift/release/6.2",
+                "swift": "release/6.2",
+                "cmark": "gfm",
+                "llbuild": "release/6.2",
+                "swift-build": "release/6.2",
+                "swift-toolchain-sqlite": "1.0.1",
+                "swift-tools-support-core": "release/6.2",
+                "swiftpm": "release/6.2",
+                "swift-argument-parser": "1.4.0",
+                "swift-atomics": "1.2.0",
+                "swift-collections": "1.1.3",
+                "swift-crypto": "3.0.0",
+                "swift-certificates": "1.0.1",
+                "swift-asn1": "1.0.0",
+                "swift-async-algorithms": "1.0.1",
+                "swift-driver": "release/6.2",
+                "swift-log": "1.5.4",
+                "swift-numerics": "1.0.2",
+                "swift-syntax": "release/6.2",
+                "swift-system": "1.5.0",
+                "swift-stress-tester": "release/6.2",
+                "swift-testing": "release/6.2",
+                "swift-corelibs-xctest": "release/6.2",
+                "swift-corelibs-foundation": "release/6.2",
+                "swift-foundation-icu": "release/6.2",
+                "swift-foundation": "release/6.2",
+                "swift-corelibs-libdispatch": "release/6.2",
+                "swift-integration-tests": "release/6.2",
+                "swift-xcode-playground-support": "release/6.2",
+                "ninja": "v1.11.1",
+                "cmake": "v3.30.2",
+                "indexstore-db": "release/6.2",
+                "sourcekit-lsp": "release/6.2",
+                "swift-format": "release/6.2",
+                "swift-installer-scripts": "release/6.2",
+                "swift-docc": "release/6.2",
+                "swift-lmdb": "release/6.2",
+                "swift-docc-render-artifact": "release/6.2",
+                "swift-docc-symbolkit": "release/6.2",
+                "swift-markdown": "release/6.2",
+                "swift-nio": "2.65.0",
+                "swift-experimental-string-processing": "release/6.2",
+                "swift-sdk-generator": "release/6.2",
+                "wasi-libc": "wasi-sdk-24",
+                "wasmkit": "0.1.6",
+                "curl": "curl-8_9_1",
+                "libxml2": "v2.11.5",
+                "zlib": "v1.3.1",
+                "mimalloc": "v3.0.1"
+            }
+        },
+        "release/6.2.0": {
+            "aliases": ["swift/release/6.2.0", "release/6.2.0"],
+            "repos": {
+                "llvm-project": "swift/release/6.2.0",
+                "swift-llvm-bindings": "swift/release/6.2.0",
+                "swift": "release/6.2.0",
+                "cmark": "gfm",
+                "llbuild": "release/6.2.0",
+                "swift-build": "release/6.2.0",
+                "swift-toolchain-sqlite": "1.0.1",
+                "swift-tools-support-core": "release/6.2.0",
+                "swiftpm": "release/6.2.0",
+                "swift-argument-parser": "1.4.0",
+                "swift-atomics": "1.2.0",
+                "swift-collections": "1.1.3",
+                "swift-crypto": "3.0.0",
+                "swift-certificates": "1.0.1",
+                "swift-asn1": "1.0.0",
+                "swift-async-algorithms": "1.0.1",
+                "swift-driver": "release/6.2.0",
+                "swift-log": "1.5.4",
+                "swift-numerics": "1.0.2",
+                "swift-syntax": "release/6.2.0",
+                "swift-system": "1.5.0",
+                "swift-stress-tester": "release/6.2.0",
+                "swift-testing": "release/6.2.0",
+                "swift-corelibs-xctest": "release/6.2.0",
+                "swift-corelibs-foundation": "release/6.2.0",
+                "swift-foundation-icu": "release/6.2.0",
+                "swift-foundation": "release/6.2.0",
+                "swift-corelibs-libdispatch": "release/6.2.0",
+                "swift-integration-tests": "release/6.2.0",
+                "swift-xcode-playground-support": "release/6.2.0",
+                "ninja": "v1.11.1",
+                "cmake": "v3.30.2",
+                "indexstore-db": "release/6.2.0",
+                "sourcekit-lsp": "release/6.2.0",
+                "swift-format": "release/6.2.0",
+                "swift-installer-scripts": "release/6.2.0",
+                "swift-docc": "release/6.2.0",
+                "swift-lmdb": "release/6.2.0",
+                "swift-docc-render-artifact": "release/6.2.0",
+                "swift-docc-symbolkit": "release/6.2.0",
+                "swift-markdown": "release/6.2.0",
+                "swift-nio": "2.65.0",
+                "swift-experimental-string-processing": "release/6.2.0",
+                "swift-sdk-generator": "release/6.2.0",
                 "wasi-libc": "wasi-sdk-24",
                 "wasmkit": "0.1.2",
                 "curl": "curl-8_9_1",
@@ -180,6 +294,115 @@
                 "mimalloc": "v3.0.1"
             }
         },
+        "release/6.2.1": {
+            "aliases": ["swift/release/6.2.1", "release/6.2.1"],
+            "repos": {
+                "llvm-project": "swift/release/6.2.1",
+                "swift-llvm-bindings": "swift/release/6.2.1",
+                "swift": "release/6.2.1",
+                "cmark": "gfm",
+                "llbuild": "release/6.2.1",
+                "swift-build": "release/6.2.1",
+                "swift-toolchain-sqlite": "1.0.1",
+                "swift-tools-support-core": "release/6.2.1",
+                "swiftpm": "release/6.2.1",
+                "swift-argument-parser": "1.4.0",
+                "swift-atomics": "1.2.0",
+                "swift-collections": "1.1.3",
+                "swift-crypto": "3.0.0",
+                "swift-certificates": "1.0.1",
+                "swift-asn1": "1.0.0",
+                "swift-async-algorithms": "1.0.1",
+                "swift-driver": "release/6.2.1",
+                "swift-log": "1.5.4",
+                "swift-numerics": "1.0.2",
+                "swift-syntax": "release/6.2.1",
+                "swift-system": "1.5.0",
+                "swift-stress-tester": "release/6.2.1",
+                "swift-testing": "release/6.2.1",
+                "swift-corelibs-xctest": "release/6.2.1",
+                "swift-corelibs-foundation": "release/6.2.1",
+                "swift-foundation-icu": "release/6.2.1",
+                "swift-foundation": "release/6.2.1",
+                "swift-corelibs-libdispatch": "release/6.2.1",
+                "swift-integration-tests": "release/6.2.1",
+                "swift-xcode-playground-support": "release/6.2.1",
+                "ninja": "v1.11.1",
+                "cmake": "v3.30.2",
+                "indexstore-db": "release/6.2.1",
+                "sourcekit-lsp": "release/6.2.1",
+                "swift-format": "release/6.2.1",
+                "swift-installer-scripts": "release/6.2.1",
+                "swift-docc": "release/6.2.1",
+                "swift-lmdb": "release/6.2.1",
+                "swift-docc-render-artifact": "release/6.2.1",
+                "swift-docc-symbolkit": "release/6.2.1",
+                "swift-markdown": "release/6.2.1",
+                "swift-nio": "2.65.0",
+                "swift-experimental-string-processing": "release/6.2.1",
+                "swift-sdk-generator": "release/6.2.1",
+                "wasi-libc": "wasi-sdk-24",
+                "wasmkit": "0.1.6",
+                "curl": "curl-8_9_1",
+                "libxml2": "v2.11.5",
+                "zlib": "v1.3.1",
+                "mimalloc": "v3.0.1"
+            }
+        },
+        "release/6.1.1": {
+            "aliases": ["swift/release/6.1.1", "release/6.1.1"],
+            "repos": {
+                "llvm-project": "swift/release/6.1.1",
+                "swift-llvm-bindings": "swift/release/6.1.1",
+                "swift": "release/6.1.1",
+                "cmark": "release/6.1.1",
+                "llbuild": "release/6.1.1",
+                "swift-toolchain-sqlite": "1.0.1",
+                "swift-tools-support-core": "release/6.1.1",
+                "swiftpm": "release/6.1.1",
+                "swift-argument-parser": "1.4.0",
+                "swift-atomics": "1.2.0",
+                "swift-collections": "1.1.3",
+                "swift-crypto": "3.0.0",
+                "swift-certificates": "1.0.1",
+                "swift-asn1": "1.0.0",
+                "swift-async-algorithms": "1.0.1",
+                "swift-driver": "release/6.1.1",
+                "swift-log": "1.5.4",
+                "swift-numerics": "1.0.2",
+                "swift-syntax": "release/6.1.1",
+                "swift-system": "1.3.0",
+                "swift-stress-tester": "release/6.1.1",
+                "swift-testing": "release/6.1.1",
+                "swift-corelibs-xctest": "release/6.1.1",
+                "swift-corelibs-foundation": "release/6.1.1",
+                "swift-foundation-icu": "release/6.1.1",
+                "swift-foundation": "release/6.1.1",
+                "swift-corelibs-libdispatch": "release/6.1.1",
+                "swift-integration-tests": "release/6.1.1",
+                "swift-xcode-playground-support": "release/6.1.1",
+                "ninja": "v1.11.1",
+                "yams": "5.0.6",
+                "cmake": "v3.30.2",
+                "indexstore-db": "release/6.1.1",
+                "sourcekit-lsp": "release/6.1.1",
+                "swift-format": "release/6.1.1",
+                "swift-installer-scripts": "release/6.1.1",
+                "swift-docc": "release/6.1.1",
+                "swift-lmdb": "release/6.1.1",
+                "swift-docc-render-artifact": "release/6.1.1",
+                "swift-docc-symbolkit": "release/6.1.1",
+                "swift-markdown": "release/6.1.1",
+                "swift-nio": "2.65.0",
+                "swift-experimental-string-processing": "swift/release/6.1.1",
+                "swift-sdk-generator": "release/6.1.1",
+                "wasi-libc": "wasi-sdk-22",
+                "wasmkit": "0.1.2",
+                "curl": "curl-8_9_1",
+                "libxml2": "v2.11.5",
+                "zlib": "v1.3.1"
+            }
+        },
         "release/6.1": {
             "aliases": ["swift/release/6.1", "release/6.1"],
             "repos": {
@@ -334,29 +557,29 @@
             }
         },
         "rebranch": {
-            "aliases": ["rebranch"],
+            "aliases": ["rebranch", "llvm.org/main"],
             "repos": {
-                "llvm-project": "stable/20240723",
-                "swift-llvm-bindings": "stable/20240723",
+                "llvm-project": "stable/21.x",
+                "swift-llvm-bindings": "stable/21.x",
                 "swift": "rebranch",
                 "cmark": "gfm",
                 "llbuild": "main",
                 "swift-build": "main",
-                "swift-toolchain-sqlite": "1.0.1",
+                "swift-toolchain-sqlite": "1.0.7",
                 "swift-tools-support-core": "main",
                 "swiftpm": "main",
-                "swift-argument-parser": "1.4.0",
+                "swift-argument-parser": "1.5.1",
                 "swift-atomics": "1.2.0",
-                "swift-collections": "1.1.3",
-                "swift-crypto": "3.0.0",
-                "swift-certificates": "1.0.1",
-                "swift-asn1": "1.0.0",
+                "swift-collections": "1.1.6",
+                "swift-crypto": "3.12.5",
+                "swift-certificates": "1.10.1",
+                "swift-asn1": "1.3.2",
                 "swift-async-algorithms": "1.0.1",
-                "swift-driver": "rebranch",
+                "swift-driver": "main",
                 "swift-log": "1.5.4",
                 "swift-numerics": "1.0.2",
                 "swift-syntax": "main",
-                "swift-system": "1.4.1",
+                "swift-system": "1.5.0",
                 "swift-stress-tester": "main",
                 "swift-testing": "main",
                 "swift-corelibs-xctest": "main",
@@ -366,8 +589,7 @@
                 "swift-corelibs-libdispatch": "main",
                 "swift-integration-tests": "main",
                 "swift-xcode-playground-support": "main",
-                "ninja": "v1.11.1",
-                "yams": "5.1.3",
+                "ninja": "v1.13.1",
                 "cmake": "v3.30.2",
                 "indexstore-db": "main",
                 "sourcekit-lsp": "main",
@@ -379,14 +601,15 @@
                 "swift-docc-symbolkit": "main",
                 "swift-markdown": "main",
                 "swift-nio": "2.65.0",
-                "swift-experimental-string-processing": "swift/main",
+                "swift-experimental-string-processing": "main",
                 "swift-sdk-generator": "main",
-                "wasi-libc": "wasi-sdk-24",
-                "wasmkit": "0.1.2",
+                "wasi-libc": "wasi-sdk-27",
+                "wasmkit": "0.1.6",
                 "curl": "curl-8_9_1",
                 "libxml2": "v2.11.5",
                 "zlib": "v1.3.1",
-                "mimalloc": "v3.0.1"
+                "mimalloc": "v3.0.3",
+                "swift-subprocess": "0.1"
             }
         },
         "next" : {
@@ -400,43 +623,51 @@
                 "cmark": "gfm",
                 "llbuild": "main",
                 "swift-build": "main",
-                "swift-toolchain-sqlite": "1.0.1",
+                "swift-toolchain-sqlite": "1.0.7",
                 "swift-tools-support-core": "main",
                 "swiftpm": "main",
-                "swift-argument-parser": "1.4.0",
-                "swift-async-algorithms": "1.0.1",
+                "swift-argument-parser": "1.5.1",
                 "swift-atomics": "1.2.0",
-                "swift-collections": "1.1.3",
-                "swift-crypto": "3.0.0",
-                "swift-certificates": "1.0.1",
-                "swift-asn1": "1.0.0",
+                "swift-collections": "1.1.6",
+                "swift-crypto": "3.12.5",
+                "swift-certificates": "1.10.1",
+                "swift-asn1": "1.3.2",
+                "swift-async-algorithms": "1.0.1",
                 "swift-driver": "main",
                 "swift-log": "1.5.4",
                 "swift-numerics": "1.0.2",
                 "swift-syntax": "main",
-                "swift-system": "1.4.1",
+                "swift-system": "1.5.0",
                 "swift-stress-tester": "main",
                 "swift-testing": "main",
                 "swift-corelibs-xctest": "main",
                 "swift-corelibs-foundation": "main",
+                "swift-foundation-icu": "main",
+                "swift-foundation": "main",
                 "swift-corelibs-libdispatch": "main",
                 "swift-integration-tests": "main",
                 "swift-xcode-playground-support": "main",
-                "ninja": "release",
-                "yams": "5.1.3",
+                "ninja": "v1.13.1",
                 "cmake": "v3.30.2",
                 "indexstore-db": "main",
                 "sourcekit-lsp": "main",
                 "swift-format": "main",
                 "swift-installer-scripts": "main",
+                "swift-docc": "main",
+                "swift-lmdb": "main",
+                "swift-docc-render-artifact": "main",
+                "swift-docc-symbolkit": "main",
+                "swift-markdown": "main",
                 "swift-nio": "2.65.0",
-                "swift-experimental-string-processing": "swift/main",
-                "wasi-libc": "wasi-sdk-24",
-                "wasmkit": "0.1.2",
+                "swift-experimental-string-processing": "main",
+                "swift-sdk-generator": "main",
+                "wasi-libc": "wasi-sdk-27",
+                "wasmkit": "0.1.6",
                 "curl": "curl-8_9_1",
                 "libxml2": "v2.11.5",
                 "zlib": "v1.3.1",
-                "mimalloc": "v3.0.1"
+                "mimalloc": "v3.0.3",
+                "swift-subprocess": "0.1"
             }
         }
     }
diff --git a/utils/update_checkout/update_checkout/__init__.py b/utils/update_checkout/update_checkout/__init__.py
index 99cc1c7c3d1d1..7a4ee69672705 100644
--- a/utils/update_checkout/update_checkout/__init__.py
+++ b/utils/update_checkout/update_checkout/__init__.py
@@ -1,4 +1,3 @@
-
 from .update_checkout import main
 
 __all__ = ["main"]
diff --git a/utils/update_checkout/update_checkout/parallel_runner.py b/utils/update_checkout/update_checkout/parallel_runner.py
new file mode 100644
index 0000000000000..c216fcfeb46aa
--- /dev/null
+++ b/utils/update_checkout/update_checkout/parallel_runner.py
@@ -0,0 +1,149 @@
+from multiprocessing.managers import ListProxy, ValueProxy
+import sys
+from multiprocessing import Pool, cpu_count, Manager
+import time
+from typing import Callable, List, Any, Union
+from threading import Lock, Thread, Event
+import shutil
+
+from .runner_arguments import RunnerArguments, AdditionalSwiftSourcesArguments
+
+
+class MonitoredFunction:
+    def __init__(
+        self,
+        fn: Callable,
+        running_tasks: ListProxy,
+        updated_repos: ValueProxy,
+        lock: Lock
+    ):
+        self.fn = fn
+        self.running_tasks = running_tasks
+        self.updated_repos = updated_repos
+        self._lock = lock
+
+    def __call__(self, *args: Union[RunnerArguments, AdditionalSwiftSourcesArguments]):
+        task_name = args[0].repo_name
+        self.running_tasks.append(task_name)
+        result = None
+        try:
+            result = self.fn(*args)
+        except Exception as e:
+            print(e)
+        finally:
+            self._lock.acquire()
+            if task_name in self.running_tasks:
+                self.running_tasks.remove(task_name)
+            self.updated_repos.set(self.updated_repos.get() + 1)
+            self._lock.release()
+            return result
+
+
+class ParallelRunner:
+    def __init__(
+        self,
+        fn: Callable,
+        pool_args: List[Union[RunnerArguments, AdditionalSwiftSourcesArguments]],
+        n_processes: int = 0,
+    ):
+        self._monitor_polling_period = 0.1
+        if n_processes == 0:
+            if sys.version_info.minor < 10:
+                # On Python < 3.10, https://bugs.python.org/issue46391 causes
+                # Pool.map and its variants to hang. Limiting the number of
+                # processes fixes the issue.
+                n_processes = int(cpu_count() * 1.25)
+            else:
+                n_processes = cpu_count() * 2
+        self._terminal_width = shutil.get_terminal_size().columns
+        self._n_processes = n_processes
+        self._pool_args = pool_args
+        self._fn = fn
+        self._pool = Pool(processes=self._n_processes)
+        self._output_prefix = pool_args[0].output_prefix
+        self._nb_repos = len(pool_args)
+        self._stop_event = Event()
+        self._verbose = pool_args[0].verbose
+        if not self._verbose:
+            manager = Manager()
+            self._lock = manager.Lock()
+            self._running_tasks = manager.list()
+            self._updated_repos = manager.Value("i", 0)
+            self._monitored_fn = MonitoredFunction(
+                self._fn, self._running_tasks, self._updated_repos, self._lock
+            )
+
+    def run(self) -> List[Any]:
+        print(
+            "Running ``%s`` with up to %d processes."
+            % (self._fn.__name__, self._n_processes)
+        )
+        if self._verbose:
+            results = self._pool.map_async(
+                func=self._fn, iterable=self._pool_args
+            ).get(timeout=1800)
+            self._pool.close()
+            self._pool.join()
+        else:
+            monitor_thread = Thread(target=self._monitor, daemon=True)
+            monitor_thread.start()
+            results = self._pool.map_async(
+                func=self._monitored_fn, iterable=self._pool_args
+            ).get(timeout=1800)
+            self._pool.close()
+            self._pool.join()
+            self._stop_event.set()
+            monitor_thread.join()
+        return results
+
+    def _monitor(self):
+        last_output = ""
+        while not self._stop_event.is_set():
+            self._lock.acquire()
+            current = list(self._running_tasks)
+            current_line = ", ".join(current)
+            updated_repos = self._updated_repos.get()
+            self._lock.release()
+
+            if current_line != last_output:
+                truncated = (f"{self._output_prefix} [{updated_repos}/{self._nb_repos}] ({current_line})")
+                if len(truncated) > self._terminal_width:
+                    ellipsis_marker = " ..."
+                    truncated = (
+                        truncated[: self._terminal_width - len(ellipsis_marker)]
+                        + ellipsis_marker
+                    )
+                sys.stdout.write("\r" + truncated.ljust(self._terminal_width))
+                sys.stdout.flush()
+                last_output = current_line
+
+            time.sleep(self._monitor_polling_period)
+
+        sys.stdout.write("\r" + " " * len(last_output) + "\r\n")
+        sys.stdout.flush()
+
+    @staticmethod
+    def check_results(results, op) -> int:
+        """Function used to check the results of ParallelRunner.
+
+        NOTE: This function was originally located in the shell module of
+        swift_build_support and should eventually be replaced with a better
+        parallel implementation.
+        """
+
+        fail_count = 0
+        if results is None:
+            return 0
+        for r in results:
+            if r is not None:
+                if fail_count == 0:
+                    print("======%s FAILURES======" % op)
+                fail_count += 1
+                if isinstance(r, str):
+                    print(r)
+                    continue
+                print("%s failed (ret=%d): %s" % (r.repo_path, r.ret, r))
+                if r.stderr:
+                    print(r.stderr.decode())
+        return fail_count
+
diff --git a/utils/update_checkout/update_checkout/runner_arguments.py b/utils/update_checkout/update_checkout/runner_arguments.py
new file mode 100644
index 0000000000000..6d542c838336c
--- /dev/null
+++ b/utils/update_checkout/update_checkout/runner_arguments.py
@@ -0,0 +1,33 @@
+from dataclasses import dataclass
+from typing import Any, Dict
+
+@dataclass
+class RunnerArguments:
+    repo_name: str
+    scheme_name: str
+    output_prefix: str
+    verbose: bool
+
+@dataclass
+class UpdateArguments(RunnerArguments):
+    source_root: str
+    config: Dict[str, Any]
+    scheme_map: Any
+    tag: str
+    timestamp: Any
+    reset_to_remote: bool
+    clean: bool
+    stash: bool
+    cross_repos_pr: bool
+
+@dataclass
+class AdditionalSwiftSourcesArguments(RunnerArguments):
+    args: RunnerArguments
+    repo_info: str
+    repo_branch: str
+    remote: str
+    with_ssh: bool
+    skip_history: bool
+    skip_tags: bool
+    skip_repository_list: bool
+    use_submodules: bool
diff --git a/utils/update_checkout/update_checkout/update_checkout.py b/utils/update_checkout/update_checkout/update_checkout.py
index 01cb9dd0e38be..70cf5f38a5e01 100755
--- a/utils/update_checkout/update_checkout/update_checkout.py
+++ b/utils/update_checkout/update_checkout/update_checkout.py
@@ -13,69 +13,45 @@
 import os
 import platform
 import re
+import tempfile
 import sys
 import traceback
-from multiprocessing import Lock, Pool, cpu_count, freeze_support
+from multiprocessing import freeze_support
+from typing import Any, Dict, Optional, Set, List
 
 from build_swift.build_swift.constants import SWIFT_SOURCE_ROOT
-
+from .runner_arguments import AdditionalSwiftSourcesArguments, UpdateArguments
+from .parallel_runner import ParallelRunner
 from swift_build_support.swift_build_support import shell
 
 
 SCRIPT_FILE = os.path.abspath(__file__)
 SCRIPT_DIR = os.path.dirname(SCRIPT_FILE)
 
+def is_unix_sock_path_too_long() -> bool:
+    """Check if the unix socket_path exceeds the 104 limit (108 on Linux).
 
-def child_init(lck):
-    global lock
-    lock = lck
-
+    The multiprocessing module creates a socket in the TEMPDIR folder. The
+    socket path should not exceed:
+        - 104 bytes on macOS
+        - 108 bytes on Linux (https://www.man7.org/linux/man-pages/man7/unix.7.html)
 
-def run_parallel(fn, pool_args, n_processes=0):
-    """Function used to run a given closure in parallel.
-
-    NOTE: This function was originally located in the shell module of
-    swift_build_support and should eventually be replaced with a better
-    parallel implementation.
+    Returns:
+        bool: Whether the socket path exceeds the limit. Always False on Windows.
     """
 
-    if n_processes == 0:
-        n_processes = cpu_count() * 2
+    if os.name != "posix":
+        return False
 
-    lk = Lock()
-    print("Running ``%s`` with up to %d processes." %
-          (fn.__name__, n_processes))
-    pool = Pool(processes=n_processes, initializer=child_init, initargs=(lk,))
-    results = pool.map_async(func=fn, iterable=pool_args).get(999999)
-    pool.close()
-    pool.join()
-    return results
+    MAX_UNIX_SOCKET_PATH = 104
+    # `tempfile.mktemp` is deprecated yet that's what the multiprocessing
+    # module uses internally: https://github.com/python/cpython/blob/c4e7d245d61ac4547ecf3362b28f64fc00aa88c0/Lib/multiprocessing/connection.py#L72
+    # Since we are not using the resulting file, it is safe to use this
+    # method.
+    sock_path = tempfile.mktemp(prefix="sock-", dir=tempfile.gettempdir())
+    return len(sock_path.encode("utf-8")) > MAX_UNIX_SOCKET_PATH
 
-
-def check_parallel_results(results, op):
-    """Function used to check the results of run_parallel.
-
-    NOTE: This function was originally located in the shell module of
-    swift_build_support and should eventually be replaced with a better
-    parallel implementation.
-    """
-
-    fail_count = 0
-    if results is None:
-        return 0
-    for r in results:
-        if r is not None:
-            if fail_count == 0:
-                print("======%s FAILURES======" % op)
-            print("%s failed (ret=%d): %s" % (r.repo_path, r.ret, r))
-            fail_count += 1
-            if r.stderr:
-                print(r.stderr)
-    return fail_count
-
-
-def confirm_tag_in_repo(tag, repo_name):
-    # type: (str, str) -> str | None
+def confirm_tag_in_repo(tag: str, repo_name: str) -> Optional[str]:
     """Confirm that a given tag exists in a git repository. This function
     assumes that the repository is already a current working directory before
     it's called.
@@ -98,9 +74,16 @@ def confirm_tag_in_repo(tag, repo_name):
     return tag
 
 
-def find_rev_by_timestamp(timestamp, repo_name, refspec):
+def find_rev_by_timestamp(timestamp: str, repo_name: str, refspec: str) -> str:
+    refspec_exists = True
+    try:
+        shell.run(["git", "rev-parse", "--verify", refspec])
+    except Exception:
+        refspec_exists = False
     args = ["git", "log", "-1", "--format=%H", "--first-parent",
-            '--before=' + timestamp, refspec]
+            '--before=' + timestamp]
+    if refspec_exists:
+        args.append(refspec)
     rev = shell.capture(args).strip()
     if rev:
         return rev
@@ -146,27 +129,29 @@ def get_branch_for_repo(config, repo_name, scheme_name, scheme_map,
     return repo_branch, cross_repo
 
 
-def update_single_repository(pool_args):
-    source_root, config, repo_name, scheme_name, scheme_map, tag, timestamp, \
-        reset_to_remote, should_clean, should_stash, cross_repos_pr = pool_args
-    repo_path = os.path.join(source_root, repo_name)
+def update_single_repository(pool_args: UpdateArguments):
+    verbose = pool_args.verbose
+    repo_name = pool_args.repo_name
+
+    repo_path = os.path.join(pool_args.source_root, repo_name)
     if not os.path.isdir(repo_path) or os.path.islink(repo_path):
         return
 
     try:
         prefix = "[{0}] ".format(os.path.basename(repo_path)).ljust(40)
-        print(prefix + "Updating '" + repo_path + "'")
+        if verbose:
+            print(prefix + "Updating '" + repo_path + "'")
 
-        with shell.pushd(repo_path, dry_run=False, echo=False):
+        with shell.pushd(repo_path, dry_run=False, echo=verbose):
             cross_repo = False
             checkout_target = None
-            if tag:
-                checkout_target = confirm_tag_in_repo(tag, repo_name)
-            elif scheme_name:
+            if pool_args.tag:
+                checkout_target = confirm_tag_in_repo(pool_args.tag, repo_name)
+            elif pool_args.scheme_name:
                 checkout_target, cross_repo = get_branch_for_repo(
-                    config, repo_name, scheme_name, scheme_map, cross_repos_pr)
-                if timestamp:
-                    checkout_target = find_rev_by_timestamp(timestamp,
+                    pool_args.config, repo_name, pool_args.scheme_name, pool_args.scheme_map, pool_args.cross_repos_pr)
+                if pool_args.timestamp:
+                    checkout_target = find_rev_by_timestamp(pool_args.timestamp,
                                                             repo_name,
                                                             checkout_target)
 
@@ -175,20 +160,20 @@ def update_single_repository(pool_args):
             #   changes rather than discarding them)
             # 2. delete ignored files
             # 3. abort an ongoing rebase
-            if should_clean or should_stash:
+            if pool_args.clean or pool_args.stash:
 
                 def run_for_repo_and_each_submodule_rec(cmd):
-                    shell.run(cmd, echo=True, prefix=prefix)
+                    shell.run(cmd, echo=verbose, prefix=prefix)
                     shell.run(
                         ["git", "submodule", "foreach", "--recursive"] + cmd,
-                        echo=True,
+                        echo=verbose,
                         prefix=prefix,
                     )
 
-                if should_stash:
+                if pool_args.clean:
                     # Stash tracked and untracked changes.
                     run_for_repo_and_each_submodule_rec(["git", "stash", "-u"])
-                elif should_clean:
+                elif pool_args.stash:
                     # Delete tracked changes.
                     run_for_repo_and_each_submodule_rec(
                         ["git", "reset", "--hard", "HEAD"]
@@ -201,7 +186,7 @@ def run_for_repo_and_each_submodule_rec(cmd):
                 # It is possible to reset --hard and still be mid-rebase.
                 try:
                     shell.run(['git', 'rebase', '--abort'],
-                              echo=True, prefix=prefix)
+                              echo=verbose, prefix=prefix)
                 except Exception:
                     pass
 
@@ -218,32 +203,32 @@ def run_for_repo_and_each_submodule_rec(cmd):
                 except Exception:
                     shell.run(["git", "fetch", "--recurse-submodules=yes",
                                "--tags"],
-                              echo=True, prefix=prefix)
+                              echo=verbose, prefix=prefix)
 
                 try:
                     shell.run(['git', 'checkout', checkout_target],
-                              echo=True, prefix=prefix)
-                except Exception as originalException:
+                              echo=verbose, prefix=prefix)
+                except Exception:
                     try:
                         result = shell.run(['git', 'rev-parse', checkout_target])
                         revision = result[0].strip()
                         shell.run(['git', 'checkout', revision],
-                                  echo=True, prefix=prefix)
+                                  echo=verbose, prefix=prefix)
                     except Exception:
-                        raise originalException
+                        raise
 
             # It's important that we checkout, fetch, and rebase, in order.
             # .git/FETCH_HEAD updates the not-for-merge attributes based on
             # which branch was checked out during the fetch.
             shell.run(["git", "fetch", "--recurse-submodules=yes", "--tags"],
-                      echo=True, prefix=prefix)
+                      echo=verbose, prefix=prefix)
 
             # If we were asked to reset to the specified branch, do the hard
             # reset and return.
-            if checkout_target and reset_to_remote and not cross_repo:
+            if checkout_target and pool_args.reset_to_remote and not cross_repo:
                 full_target = full_target_name('origin', checkout_target)
                 shell.run(['git', 'reset', '--hard', full_target],
-                          echo=True, prefix=prefix)
+                          echo=verbose, prefix=prefix)
                 return
 
             # Query whether we have a "detached HEAD", which will mean that
@@ -271,17 +256,18 @@ def run_for_repo_and_each_submodule_rec(cmd):
             # http://stackoverflow.com/a/30209750/125349
             if not cross_repo and not detached_head:
                 shell.run(["git", "rebase", "FETCH_HEAD"],
-                          echo=True, prefix=prefix)
-            elif detached_head:
+                          echo=verbose, prefix=prefix)
+            elif detached_head and verbose:
                 print(prefix +
                       "Detached HEAD; probably checked out a tag. No need "
                       "to rebase.")
 
             shell.run(["git", "submodule", "update", "--recursive"],
-                      echo=True, prefix=prefix)
+                      echo=verbose, prefix=prefix)
     except Exception:
         (type, value, tb) = sys.exc_info()
-        print('Error on repo "%s": %s' % (repo_path, traceback.format_exc()))
+        if verbose:
+            print('Error on repo "%s": %s' % (repo_path, traceback.format_exc()))
         return value
 
 
@@ -329,6 +315,30 @@ def get_scheme_map(config, scheme_name):
 
     return None
 
+def _is_any_repository_locked(pool_args: List[UpdateArguments]) -> Set[str]:
+    """Returns the set of locked repositories.
+
+    A repository is considered to be locked if its .git directory contains a
+    file ending in ".lock".
+
+    Args:
+        pool_args (List[Any]): List of arguments passed to the
+        `update_single_repository` function.
+
+    Returns:
+        Set[str]: The names of the locked repositories if any.
+    """
+
+    repos = [(x.source_root, x.repo_name) for x in pool_args]
+    locked_repositories = set()
+    for source_root, repo_name in repos:
+        dot_git_path = os.path.join(source_root, repo_name, ".git")
+        if not os.path.exists(dot_git_path) or not os.path.isdir(dot_git_path):
+            continue
+        for file in os.listdir(dot_git_path):
+            if file.endswith(".lock"):
+                locked_repositories.add(repo_name)
+    return locked_repositories
 
 def update_all_repositories(args, config, scheme_name, scheme_map, cross_repos_pr):
     pool_args = []
@@ -351,44 +361,65 @@ def update_all_repositories(args, config, scheme_name, scheme_map, cross_repos_p
                 )
             continue
 
-        my_args = [args.source_root, config,
-                   repo_name,
-                   scheme_name,
-                   scheme_map,
-                   args.tag,
-                   timestamp,
-                   args.reset_to_remote,
-                   args.clean,
-                   args.stash,
-                   cross_repos_pr]
+        my_args = UpdateArguments(
+            source_root=args.source_root,
+            config=config,
+            repo_name=repo_name,
+            scheme_name=scheme_name,
+            scheme_map=scheme_map,
+            tag=args.tag,
+            timestamp=timestamp,
+            reset_to_remote=args.reset_to_remote,
+            clean=args.clean,
+            stash=args.stash,
+            cross_repos_pr=cross_repos_pr,
+            output_prefix="Updating",
+            verbose=args.verbose,
+        )
         pool_args.append(my_args)
 
-    return run_parallel(update_single_repository, pool_args, args.n_processes)
+    locked_repositories: set[str] = _is_any_repository_locked(pool_args)
+    if len(locked_repositories) > 0:
+        return [
+            f"'{repo_name}' is locked by git. Cannot update it."
+            for repo_name in locked_repositories
+        ]
+    return ParallelRunner(update_single_repository, pool_args, args.n_processes).run()
 
 
-def obtain_additional_swift_sources(pool_args):
-    (args, repo_name, repo_info, repo_branch, remote, with_ssh, scheme_name,
-     skip_history, skip_tags, skip_repository_list) = pool_args
+def obtain_additional_swift_sources(pool_args: AdditionalSwiftSourcesArguments):
+    args = pool_args.args
+    repo_name = pool_args.repo_name
+    repo_branch = pool_args.repo_branch
+    verbose = pool_args.verbose
+    skip_tags = pool_args.skip_tags
+    remote = pool_args.remote
 
     env = dict(os.environ)
     env.update({'GIT_TERMINAL_PROMPT': '0'})
 
     with shell.pushd(args.source_root, dry_run=False, echo=False):
 
-        print("Cloning '" + repo_name + "'")
+        if verbose:
+            print("Cloning '" + pool_args.repo_name + "'")
 
-        if skip_history:
+        if pool_args.skip_history:
             shell.run(['git', 'clone', '--recursive', '--depth', '1',
                        '--branch', repo_branch, remote, repo_name] +
                       (['--no-tags'] if skip_tags else []),
                       env=env,
-                      echo=True)
+                      echo=verbose)
+        elif pool_args.use_submodules:
+            shell.run(['git', 'submodule', 'add', remote, repo_name] +
+                      (['--no-tags'] if skip_tags else []),
+                      env=env,
+                      echo=verbose)
         else:
             shell.run(['git', 'clone', '--recursive', remote, repo_name] +
                       (['--no-tags'] if skip_tags else []),
                       env=env,
-                      echo=True)
-        if scheme_name:
+                      echo=verbose)
+        if pool_args.scheme_name:
             src_path = os.path.join(args.source_root, repo_name, ".git")
             shell.run(['git', '--git-dir',
                        src_path, '--work-tree',
@@ -406,7 +437,7 @@ def obtain_additional_swift_sources(pool_args):
 
 def obtain_all_additional_swift_sources(args, config, with_ssh, scheme_name,
                                         skip_history, skip_tags,
-                                        skip_repository_list):
+                                        skip_repository_list, use_submodules):
 
     pool_args = []
     with shell.pushd(args.source_root, dry_run=False, echo=False):
@@ -416,7 +447,20 @@ def obtain_all_additional_swift_sources(args, config, with_ssh, scheme_name,
                       "user")
                 continue
 
-            if os.path.isdir(os.path.join(repo_name, ".git")):
+            if use_submodules:
+              repo_exists = False
+              submodules_status = shell.capture(['git', 'submodule', 'status'],
+                                                echo=False)
+              if submodules_status:
+                for line in submodules_status.splitlines():
+                  if line[0].endswith(repo_name):
+                    repo_exists = True
+                    break
+
+            else:
+              repo_exists = os.path.isdir(os.path.join(repo_name, ".git"))
+
+            if repo_exists:
                 print("Skipping clone of '" + repo_name + "', directory "
                       "already exists")
                 continue
@@ -450,16 +494,36 @@ def obtain_all_additional_swift_sources(args, config, with_ssh, scheme_name,
             if repo_not_in_scheme:
                 continue
 
-            pool_args.append([args, repo_name, repo_info, repo_branch, remote,
-                              with_ssh, scheme_name, skip_history, skip_tags,
-                              skip_repository_list])
+            new_args = AdditionalSwiftSourcesArguments(
+                args=args,
+                repo_name=repo_name,
+                repo_info=repo_info,
+                repo_branch=repo_branch,
+                remote=remote,
+                with_ssh=with_ssh,
+                scheme_name=scheme_name,
+                skip_history=skip_history,
+                skip_tags=skip_tags,
+                skip_repository_list=skip_repository_list,
+                use_submodules=use_submodules,
+                output_prefix="Cloning",
+                verbose=args.verbose,
+            )
+
+            if use_submodules:
+                obtain_additional_swift_sources(new_args)
+            else:
+                pool_args.append(new_args)
 
-    if not pool_args:
-        print("Not cloning any repositories.")
-        return
+    # Only use `ParallelRunner` when submodules are not used, since `.git` dir
+    # can't be accessed concurrently.
+    if not use_submodules:
+      if not pool_args:
+          print("Not cloning any repositories.")
+          return
 
-    return run_parallel(
-        obtain_additional_swift_sources, pool_args, args.n_processes)
+      return ParallelRunner(
+          obtain_additional_swift_sources, pool_args, args.n_processes).run()
 
 
 def dump_repo_hashes(args, config, branch_scheme_name='repro'):
@@ -501,7 +565,41 @@ def print_repo_hashes(args, config):
         print("{:<35}: {:<35}".format(repo_name, repo_hash))
 
 
-def validate_config(config):
+def merge_no_duplicates(a: dict, b: dict) -> dict:
+    result = {**a}
+    for key, value in b.items():
+        if key in a:
+            raise ValueError(f"Duplicate scheme {key}")
+
+        result[key] = value
+    return result
+
+
+def merge_config(config: dict, new_config: dict) -> dict:
+    """
+    Merge two configs, with a 'last-wins' strategy.
+
+    The branch-schemes are rejected if they define duplicate schemes.
+    """
+
+    result = {**config}
+    for key, value in new_config.items():
+        if key == "branch-schemes":
+            # We reject duplicates here since this is the most conservative
+            # behavior, so it can be relaxed in the future.
+            # TODO: Another semantics might be nicer, define that as it is needed.
+            result[key] = merge_no_duplicates(config.get(key, {}), value)
+        elif key == "repos":
+            # The "repos" object is last-wins on a key-by-key basis
+            result[key] = {**config.get(key, {}), **value}
+        else:
+            # Anything else is just last-wins
+            result[key] = value
+
+    return result
+
+
+def validate_config(config: Dict[str, Any]):
     # Make sure that our branch-names are unique.
     scheme_names = config['branch-schemes'].keys()
     if len(scheme_names) != len(set(scheme_names)):
@@ -634,9 +732,12 @@ def main():
     )
     parser.add_argument(
         "--config",
-        default=os.path.join(SCRIPT_DIR, os.pardir,
-                             "update-checkout-config.json"),
-        help="Configuration file to use")
+        help="""The configuration file to use. Can be specified multiple times,
+        each config will be merged together with a 'last-wins' strategy.
+        Overwriting branch-schemes is not allowed.""",
+        action="append",
+        default=[],
+        dest="configs")
     parser.add_argument(
         "--github.amrom.workers.devment",
         help="""Check out related pull requests referenced in the given
@@ -672,6 +773,14 @@ def main():
         help="The root directory to checkout repositories",
         default=SWIFT_SOURCE_ROOT,
         dest='source_root')
+    parser.add_argument(
+        "--use-submodules",
+        help="Checkout repositories as git submodules.",
+        action='store_true')
+    parser.add_argument(
+        "-v", "--verbose",
+        help="Increases the script's verbosity.",
+        action='store_true')
     args = parser.parse_args()
 
     if not args.scheme:
@@ -686,6 +795,13 @@ def main():
                   "specify --scheme=foo")
             sys.exit(1)
 
+    if is_unix_sock_path_too_long():
+        print(
+            f"TEMPDIR={tempfile.gettempdir()} is too long and multiprocessing "
+            "sockets will exceed the size limit. Falling back to verbose mode."
+        )
+        args.verbose = True
+
     clone = args.clone
     clone_with_ssh = args.clone_with_ssh
     skip_history = args.skip_history
@@ -693,9 +809,17 @@ def main():
     scheme_name = args.scheme
     github.amrom.workers.devment = args.github.amrom.workers.devment
     all_repos = args.all_repositories
-
-    with open(args.config) as f:
-        config = json.load(f)
+    use_submodules = args.use_submodules
+
+    # Set the default config path if none are specified
+    if not args.configs:
+        default_path = os.path.join(SCRIPT_DIR, os.pardir,
+                                    "update-checkout-config.json")
+        args.configs.append(default_path)
+    config = {}
+    for config_path in args.configs:
+        with open(config_path) as f:
+            config = merge_config(config, json.load(f))
     validate_config(config)
 
     cross_repos_pr = {}
@@ -726,7 +850,8 @@ def main():
                                                             scheme_name,
                                                             skip_history,
                                                             skip_tags,
-                                                            skip_repo_list)
+                                                            skip_repo_list,
+                                                            use_submodules)
 
     swift_repo_path = os.path.join(args.source_root, 'swift')
     if 'swift' not in skip_repo_list and os.path.exists(swift_repo_path):
@@ -742,8 +867,10 @@ def main():
                           prefix="[swift] ")
 
                 # Re-read the config after checkout.
-                with open(args.config) as f:
-                    config = json.load(f)
+                config = {}
+                for config_path in args.configs:
+                    with open(config_path) as f:
+                        config = merge_config(config, json.load(f))
                 validate_config(config)
                 scheme_map = get_scheme_map(config, scheme_name)
 
@@ -766,8 +893,8 @@ def main():
     update_results = update_all_repositories(args, config, scheme_name,
                                              scheme_map, cross_repos_pr)
     fail_count = 0
-    fail_count += check_parallel_results(clone_results, "CLONE")
-    fail_count += check_parallel_results(update_results, "UPDATE")
+    fail_count += ParallelRunner.check_results(clone_results, "CLONE")
+    fail_count += ParallelRunner.check_results(update_results, "UPDATE")
     if fail_count > 0:
         print("update-checkout failed, fix errors and try again")
     else:
diff --git a/utils/wasm-run.py b/utils/wasm-run.py
index 74bacafa805d5..6b13cb43ca0f1 100755
--- a/utils/wasm-run.py
+++ b/utils/wasm-run.py
@@ -11,7 +11,7 @@ def collect_wasm_env(local_env=os.environ, prefix='WASM_RUN_CHILD_'):
                 for key, value in local_env.items() if key.startswith(prefix))
 
 
-class WasmtimeRunner(object):
+class WASIRunner(object):
     def __init__(self):
         pass
 
@@ -24,7 +24,7 @@ def run(self, args):
             subprocess.check_call(command)
 
     def invocation(self, args):
-        command = ["wasmkit-cli", "run"]
+        command = ["wasmkit", "run"]
         envs = collect_wasm_env()
         for key in envs:
             command.append("--env")
@@ -46,7 +46,7 @@ def main():
                         help='the command to run', metavar='command...')
 
     args = parser.parse_args()
-    runner = WasmtimeRunner()
+    runner = WASIRunner()
     runner.run(args)
 
 
diff --git a/utils/wasm/node-wasi-runner b/utils/wasm/node-wasi-runner
new file mode 100755
index 0000000000000..ecb9e308140a4
--- /dev/null
+++ b/utils/wasm/node-wasi-runner
@@ -0,0 +1,36 @@
+#!/usr/bin/env node --disable-warning=ExperimentalWarning
+
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+const { readFile } = require('node:fs/promises');
+const { WASI } = require('node:wasi');
+const { argv, env } = require('node:process');
+
+const wasmFile = argv[2];
+
+const wasi = new WASI({
+  version: 'preview1',
+  args: argv.splice(2),
+  env,
+  preopens: {
+  },
+});
+
+(async () => {
+  const wasm = await WebAssembly.compile(
+    await readFile(wasmFile)
+  );
+  const instance = await WebAssembly.instantiate(wasm, wasi.getImportObject());
+
+  wasi.start(instance);
+})();
diff --git a/utils/windows-llvm-lit-test-overrides.txt b/utils/windows-llvm-lit-test-overrides.txt
deleted file mode 100644
index 9ccfa1cde9eb7..0000000000000
--- a/utils/windows-llvm-lit-test-overrides.txt
+++ /dev/null
@@ -1,186 +0,0 @@
-# build.ps1 overrides the status of each test in this file when LLVM tests are run with lit.
-#
-# Prefer `xfail` for tests that fail reliably. Use `skip` for flaky tests.
-# Test summaries call them "excluded". Please find the right "Tests that ..."
-# category for new entries.
-
-### Tests that fail reliably ###
-
-xfail lldb-api :: lang/cpp/unique-types4/TestUniqueTypes4.py
-xfail lldb-shell :: Recognizer/verbose_trap.test
-xfail lldb-shell :: Settings/TestEchoCommands.test
-xfail lldb-shell :: Swift/MissingVFSOverlay.test
-xfail lldb-shell :: Swift/No.swiftmodule.test
-xfail lldb-shell :: Swift/ToolchainMismatch.test
-xfail lldb-shell :: Swift/global.test
-xfail lldb-shell :: Swift/runtime-initialization.test
-xfail lldb-shell :: SwiftREPL/BreakpointSimple.test
-xfail lldb-shell :: SwiftREPL/ClosureScope.test
-xfail lldb-shell :: SwiftREPL/ExistentialTypes.test
-xfail lldb-shell :: SwiftREPL/LookupAfterImport.test
-xfail lldb-shell :: SwiftREPL/LookupWithAttributedImport.test
-xfail lldb-shell :: SwiftREPL/OpenClass.test
-xfail lldb-shell :: SwiftREPL/OptionalUnowned.test
-xfail lldb-shell :: SwiftREPL/RedirectInputUnreadable.test
-xfail lldb-shell :: SwiftREPL/SwiftInterface.test
-xfail lldb-shell :: SymbolFile/DWARF/x86/dead-code-filtering.yaml
-
-### Tests that pass locally, but fail in CI reliably ###
-
-# https://github.com/swiftlang/llvm-project/issues/9539
-xfail lldb-shell :: SwiftREPL/Basic.test
-xfail lldb-shell :: SwiftREPL/Class.test
-xfail lldb-shell :: SwiftREPL/ComputedProperties.test
-xfail lldb-shell :: SwiftREPL/Deadlock.test
-xfail lldb-shell :: SwiftREPL/DiagnosticOptions.test
-xfail lldb-shell :: SwiftREPL/Dict.test
-xfail lldb-shell :: SwiftREPL/ErrorReturn.test
-xfail lldb-shell :: SwiftREPL/ExclusivityREPL.test
-xfail lldb-shell :: SwiftREPL/GenericTypealias.test
-xfail lldb-shell :: SwiftREPL/Generics.test
-xfail lldb-shell :: SwiftREPL/ImportError.test
-xfail lldb-shell :: SwiftREPL/MetatypeRepl.test
-xfail lldb-shell :: SwiftREPL/Optional.test
-xfail lldb-shell :: SwiftREPL/PropertyWrapperTopLevel.test
-xfail lldb-shell :: SwiftREPL/RecursiveClass.test
-xfail lldb-shell :: SwiftREPL/Redefinition.test
-xfail lldb-shell :: SwiftREPL/RedirectInput.test
-xfail lldb-shell :: SwiftREPL/RedirectInputNoSuchFile.test
-xfail lldb-shell :: SwiftREPL/Regex.test
-xfail lldb-shell :: SwiftREPL/SimpleExpressions.test
-xfail lldb-shell :: SwiftREPL/Struct.test
-xfail lldb-shell :: SwiftREPL/Subclassing.test
-xfail lldb-shell :: SwiftREPL/SwiftInterfaceForceModuleLoadMode.test
-xfail lldb-shell :: SwiftREPL/SwiftTypeLookup.test
-xfail lldb-shell :: SwiftREPL/SyntaxError.test
-xfail lldb-shell :: SwiftREPL/UninitVariables.test
-xfail lldb-shell :: SwiftREPL/ZeroSizeStruct.test
-xfail lldb-shell :: SwiftREPL/enum-singlecase.test
-xfail lldb-shell :: SwiftREPL/one-char-string.test
-
-xfail lldb-api :: commands/apropos/with-process/TestAproposWithProcess.py
-xfail lldb-api :: commands/command/nested_alias/TestNestedAlias.py
-xfail lldb-api :: commands/expression/entry-bp/TestExprEntryBP.py
-xfail lldb-api :: commands/memory/write/TestMemoryWrite.py
-xfail lldb-api :: functionalities/breakpoint/address_breakpoints/TestAddressBreakpoints.py
-xfail lldb-api :: functionalities/breakpoint/auto_continue/TestBreakpointAutoContinue.py
-xfail lldb-api :: functionalities/breakpoint/breakpoint_conditions/TestBreakpointConditions.py
-xfail lldb-api :: functionalities/breakpoint/breakpoint_options/TestBreakpointOptions.py
-xfail lldb-api :: functionalities/breakpoint/step_over_breakpoint/TestStepOverBreakpoint.py
-xfail lldb-api :: functionalities/conditional_break/TestConditionalBreak.py
-xfail lldb-api :: functionalities/memory/find/TestMemoryFind.py
-xfail lldb-api :: lang/c/anonymous/TestAnonymous.py
-xfail lldb-api :: lang/c/array_types/TestArrayTypes.py
-xfail lldb-api :: lang/c/enum_types/TestEnumTypes.py
-xfail lldb-api :: lang/c/forward/TestForwardDeclaration.py
-xfail lldb-api :: lang/c/function_types/TestFunctionTypes.py
-xfail lldb-api :: lang/c/register_variables/TestRegisterVariables.py
-xfail lldb-api :: lang/c/set_values/TestSetValues.py
-xfail lldb-api :: lang/c/shared_lib/TestSharedLib.py
-xfail lldb-api :: lang/cpp/class_types/TestClassTypes.py
-xfail lldb-api :: lang/cpp/inlines/TestInlines.py
-xfail lldb-api :: python_api/compile_unit/TestCompileUnitAPI.py
-xfail lldb-api :: python_api/thread/TestThreadAPI.py
-xfail lldb-api :: source-manager/TestSourceManager.py
-xfail lldb-shell :: Driver/TestConvenienceVariables.test
-
-# https://github.com/swiftlang/llvm-project/issues/9620
-xfail lldb-shell :: Swift/expression-diagnostics.test
-
-# https://github.com/swiftlang/llvm-project/issues/9540
-xfail lldb-shell :: SymbolFile/NativePDB/local-variables.cpp
-xfail lldb-shell :: SymbolFile/NativePDB/stack_unwinding01.cpp
-xfail lldb-api :: lang/c/local_variables/TestLocalVariables.py
-
-# https://github.com/swiftlang/llvm-project/issues/9637
-xfail lldb-api :: python_api/address_range/TestAddressRange.py
-
-# https://github.com/swiftlang/llvm-project/issues/9643
-xfail lldb-shell :: Commands/command-process-launch-user-entry.test
-
-# Skip SymbolTests because we cannot xfail unittests by name. We would need to
-# specify their indexes, but these are subject to change. Right now, failures
-# are:
-#  FAIL: lldb-unit :: Symbol/./SymbolTests.exe/24/27 (1 of 27)
-#  FAIL: lldb-unit :: Symbol/./SymbolTests.exe/21/27 (3 of 27)
-#  FAIL: lldb-unit :: Symbol/./SymbolTests.exe/22/27 (9 of 27)
-#  FAIL: lldb-unit :: Symbol/./SymbolTests.exe/25/27 (11 of 27)
-#
-# Respective tests are:
-#  lldb-unit :: Symbol/./SymbolTests.exe/ClangArgs/UniquingCollisionWithAddedFlags
-#  lldb-unit :: Symbol/./SymbolTests.exe/ClangArgs/UniquingCollisionWithExistingFlags
-#  lldb-unit :: Symbol/./SymbolTests.exe/TestSwiftASTContext/ApplyWorkingDir
-#  lldb-unit :: Symbol/./SymbolTests.exe/TestSwiftASTContext/PluginPath
-#
-skip lldb-unit :: Symbol/./SymbolTests.exe
-
-### Tests that fail occasionally ###
-
-# https://github.com/swiftlang/llvm-project/issues/9705
-skip lldb-api :: python_api/section/TestSectionAPI.py
-
-# Passes upstream in bot lldb-aarch64-windows; it fails in swiftlang
-# since https://github.com/swiftlang/llvm-project/pull/9493 relanded
-skip lldb-api :: functionalities/breakpoint/same_cu_name/TestFileBreakpoinsSameCUName.py
-
-# Disable 37 tests: 17 unsupported, 6 usually failed, 14 usually passed (but flaky)
-# https://github.com/swiftlang/llvm-project/issues/9099
-# https://github.com/swiftlang/llvm-project/issues/9100
-# https://github.com/swiftlang/llvm-project/issues/9101
-skip lldb-api :: tools/lldb-server
-
-### Tests that time out occasionally ###
-
-skip lldb-api :: commands/dwim-print/TestDWIMPrint.py
-skip lldb-api :: commands/thread/backtrace/TestThreadBacktraceRepeat.py
-skip lldb-api :: functionalities/inferior-crashing/TestInferiorCrashing.py
-skip lldb-api :: functionalities/inline-stepping/TestInlineStepping.py
-skip lldb-api :: functionalities/step_scripted/TestStepScripted.py
-skip lldb-api :: functionalities/thread/thread_specific_break/TestThreadSpecificBreakpoint.py
-
-### Tests that pass occasionally ###
-
-# Fixed upstream: https://github.com/llvm/llvm-project/commit/ec009994a06338995dfb6431c943b299f9327fd2
-# But patches don't apply on stable branch due to downstream changes.
-skip lldb-api :: functionalities/archives/TestBSDArchives.py
-skip lldb-api :: macosx/duplicate-archive-members/TestDuplicateMembers.py
-
-### Tests that pass accidentally ###
-
-https://github.com/llvm/llvm-project/issues/116972
-skip lldb-api :: api/command-return-object/TestSBCommandReturnObject.py
-skip lldb-api :: api/multiple-targets/TestMultipleTargets.py
-
-### Tests that fail during setup and thus show up as UNRESOLVED ***
-
-# https://github.com/swiftlang/llvm-project/issues/9887
-skip lldb-api :: lang/swift/async/tasks/TestSwiftTaskBacktrace.py
-skip lldb-api :: lang/swift/async/tasks/TestSwiftTaskSelect.py
-
-skip lldb-api :: functionalities/breakpoint/breakpoint_command/TestBreakpointCommandsFromPython.py
-skip lldb-api :: tools/lldb-dap/instruction-breakpoint/TestDAP_instruction_breakpoint.py
-skip lldb-api :: tools/lldb-dap/output/TestDAP_output.py
-
-### Untriaged ###
-
-skip lldb-api :: commands/statistics/basic/TestStats.py
-skip lldb-api :: lang/BoundsSafety/array_of_ptrs/TestArrayOfBoundsSafetyPointers.py
-skip lldb-api :: lang/BoundsSafety/out_of_bounds_pointer/TestOutOfBoundsPointer.py
-skip lldb-shell :: Commands/command-expr-diagnostics.test
-skip lldb-unit :: Host/./HostTests.exe
-
-# https://github.com/llvm/llvm-project/issues/62983
-skip lldb-api :: functionalities/var_path/TestVarPath.py
-
-# https://github.com/swiftlang/llvm-project/issues/9073
-skip lldb-api :: lang/c/trampoline_stepping/TestTrampolineStepping.py
-
-# https://github.com/swiftlang/llvm-project/issues/9072
-skip lldb-api :: lang/cpp/bitfields/TestCppBitfields.py
-
-skip lldb-shell :: Swift/astcontext_error.test
-skip lldb-shell :: Swift/cond-breakpoint.test
-
-skip lldb-api :: functionalities/data-formatter/data-formatter-cpp/TestDataFormatterCpp.py
-skip lldb-api :: lang/cpp/frame-var-depth-and-elem-count/TestFrameVarDepthAndElemCount.py
-skip lldb-api :: functionalities/inferior-crashing/recursive-inferior/TestRecursiveInferiorStep.py
diff --git a/utils/windows-swift-android-lit-test-overrides.txt b/utils/windows-swift-android-lit-test-overrides.txt
index 61c4606af4327..e0ebecc6faaf7 100644
--- a/utils/windows-swift-android-lit-test-overrides.txt
+++ b/utils/windows-swift-android-lit-test-overrides.txt
@@ -46,100 +46,18 @@ xfail Swift(android-aarch64) :: IDE/complete_with_visible_members.swift
 xfail Swift(android-aarch64) :: IDE/print_opaque_result_type.swift
 xfail Swift(android-aarch64) :: IDE/rdar141440011.swift
 xfail Swift(android-aarch64) :: Index/Store/output-failure.swift
-xfail Swift(android-aarch64) :: Interop/Cxx/class/access/private-fileid-diagnostics.swift
-xfail Swift(android-aarch64) :: Interop/Cxx/class/closure-thunk-irgen.swift
 xfail Swift(android-aarch64) :: Interop/Cxx/class/constructors-copy-irgen-android.swift
 xfail Swift(android-aarch64) :: Interop/Cxx/class/constructors-irgen-android.swift
 xfail Swift(android-aarch64) :: Interop/Cxx/class/destructors-correct-abi-irgen.swift
-xfail Swift(android-aarch64) :: Interop/Cxx/class/function-call-irgen.swift
-xfail Swift(android-aarch64) :: Interop/Cxx/foreign-reference/inheritance-diagnostics.swift
 xfail Swift(android-aarch64) :: Interop/Cxx/stdlib/android-and-std-module.swift
 xfail Swift(android-aarch64) :: Interop/Cxx/union/anonymous-union-partly-invalid.swift
 xfail Swift(android-aarch64) :: Interop/CxxToSwiftToCxx/bridge-cxx-struct-back-to-cxx.swift
 xfail Swift(android-aarch64) :: Interop/CxxToSwiftToCxx/link-cxx-type-metadata-accessor.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToC/functions/swift-primitive-functions-c-bridging.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToC/structs/large-structs-pass-return-indirect-in-c.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToC/structs/small-structs-64-bit-pass-return-direct-in-c.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToC/structs/small-structs-pass-return-direct-in-c.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/nested-classes-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/swift-actor-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/swift-class-availability-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/swift-class-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/swift-class-inheritance-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/swift-class-ordering.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/swift-class-static-variables.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/swift-resilient-class-virtual-method-dispatch.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/class/swift-subclass-of-resilient-class-virtual-method-dispatch.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/core/swift-impl-defs-in-cxx-64-bit.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/core/swift-impl-defs-in-cxx.swift
 xfail Swift(android-aarch64) :: Interop/SwiftToCxx/core/validate-swift-impl-defs-in-cxx.cpp
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/cross-module-refs/do-not-expose-imported-api-by-default.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/cross-module-refs/imported-enum-refs-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/cross-module-refs/imported-struct-refs-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/cross-module-refs/not-referenced-cross-module-import.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/enums/enum-associated-value-class-type-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/enums/enum-member-param-no-shadow-case.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/enums/large-enums-pass-return-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/enums/resilient-enum-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/enums/small-enums-generated-stub-64bit.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/enums/small-enums-pass-return-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/enums/swift-enum-implementation.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/expose-attr/expose-rename-to-unavailable-decl.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/expose-attr/expose-swift-decls-to-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/extension/struct-extension-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/cdecl.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/function-availability.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-function-argument-keyword-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-function-overloads.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-function-unsupported-cxx-type.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-functions.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-no-expose-unsupported-alwaysEmitInClient-func.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-no-expose-unsupported-async-func.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-operators.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-primitive-functions-cxx-bridging.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-primitive-inout-functions-cxx-bridging.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-simd-vector-functions-cxx-bridging.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/functions/swift-transparent-functions-cxx-bridging.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/generics/generic-enum-in-cxx.swift
 xfail Swift(android-aarch64) :: Interop/SwiftToCxx/generics/generic-function-cxx-type-invalid.cpp
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/generics/generic-function-in-cxx.swift
 xfail Swift(android-aarch64) :: Interop/SwiftToCxx/generics/generic-struct-as-generic-func-arg-in-cpp.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/generics/generic-struct-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/generics/generic-struct-known-layout-direct-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/generics/generic-struct-known-layout-indirect-in-cxx.swift
 xfail Swift(android-aarch64) :: Interop/SwiftToCxx/generics/generic-type-cxx-type-invalid.cpp
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/generics/generic-type-traits-fwd.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/initializers/init-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/initializers/swift-init-availability-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/macros/macro-name-collision.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/methods/method-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/methods/mutating-method-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/methods/swift-method-availability-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/module/module-to-namespace.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/ownership/consuming-parameter-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/properties/bool-is-has-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/properties/getter-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/properties/setter-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/properties/swift-property-availability-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/stdlib/combination-of-stdlib-generics-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/stdlib/optional/optional-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/stdlib/stdlib-dep-inline-in-cxx.swift
 xfail Swift(android-aarch64) :: Interop/SwiftToCxx/stdlib/stdlib-in-cxx-no-diagnostics-generated-header.cpp
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/stdlib/swift-stdlib-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/structs/large-structs-pass-return-indirect-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/structs/nested-structs-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/structs/resilient-struct-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/structs/small-structs-pass-return-direct-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/structs/struct-with-opaque-layout-resilient-member-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/structs/struct-with-refcounted-member.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/structs/swift-struct-availability-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/structs/swift-struct-circular-dependent-defs.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/structs/swift-struct-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/unsupported/unsupported-enums-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/unsupported/unsupported-funcs-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/unsupported/unsupported-generics-in-cxx.swift
-xfail Swift(android-aarch64) :: Interop/SwiftToCxx/unsupported/unsupported-types-in-cxx.swift
 xfail Swift(android-aarch64) :: Interop/SwiftToCxxToSwift/hide-swift-module-namespace-in-swift.swift
 xfail Swift(android-aarch64) :: Interop/SwiftToCxxToSwift/import-swift-class-back-to-swift.swift
 xfail Swift(android-aarch64) :: ModuleInterface/BadStdlib.swiftinterface
@@ -149,7 +67,6 @@ xfail Swift(android-aarch64) :: ModuleInterface/swift_build_sdk_interfaces/check
 xfail Swift(android-aarch64) :: ModuleInterface/swift_build_sdk_interfaces/compiler-uses-prebuilt-envvar.swift
 xfail Swift(android-aarch64) :: ModuleInterface/swift_build_sdk_interfaces/compiler-uses-prebuilt.swift
 xfail Swift(android-aarch64) :: ModuleInterface/swift_build_sdk_interfaces/track-system-dependencies.swift
-xfail Swift(android-aarch64) :: SIL/clang-function-types-android.swift
 xfail Swift(android-aarch64) :: SILGen/magic_identifier_file_conflicting.swift.gyb
 xfail Swift(android-aarch64) :: ScanDependencies/can_import_with_map.swift
 xfail Swift(android-aarch64) :: ScanDependencies/cannot_import_with_map_duplicate_entries.swift
@@ -191,7 +108,6 @@ xfail Swift(android-aarch64) :: api-digester/macro-gen-json.swift
 xfail Swift(android-aarch64) :: api-digester/macro-gen.swift
 xfail Swift(android-aarch64) :: sil-func-extractor/basic.sil
 xfail Swift(android-aarch64) :: sil-func-extractor/basic.swift
-xfail Swift(android-aarch64) :: stdlib/FloatConstants.swift
 
 xfail Swift-validation(android-aarch64) :: BuildSystem/android_cross_compile.test
 xfail Swift-validation(android-aarch64) :: BuildSystem/build_lld.test
@@ -243,7 +159,3 @@ xfail Swift-validation(android-aarch64) :: Sema/type_checker_perf/slow/rdar91310
 xfail Swift-validation(android-aarch64) :: compiler_crashers_2_fixed/issue-56100.swift
 xfail Swift-validation(android-aarch64) :: compiler_scale/parse_array_nested.swift.gyb
 xfail Swift-validation(android-aarch64) :: execution/unavailable_decls.swift
-
-skip Swift(android-aarch64) :: Driver/parseable_output.swift
-skip Swift(android-aarch64) :: Driver/parseable_output_unicode.swift
-skip Swift-validation(android-aarch64) :: compiler_crashers_fixed/28795-inprotocol-isrequirementsignaturecomputed-missing-signature.swift
diff --git a/validation-test/BuildSystem/android_cross_compile.test b/validation-test/BuildSystem/android_cross_compile.test
index 8396568dce764..02c71aa308ce1 100644
--- a/validation-test/BuildSystem/android_cross_compile.test
+++ b/validation-test/BuildSystem/android_cross_compile.test
@@ -1,11 +1,15 @@
 # REQUIRES: standalone_build
-# UNSUPPORTED: OS=macosx
-# UNSUPPORTED: OS=ios
-# UNSUPPORTED: OS=tvos
-# UNSUPPORTED: OS=watchos
 
 # RUN: %empty-directory(%t)
-# RUN: SKIP_XCODE_VERSION_CHECK=1 SWIFT_BUILD_ROOT=%t %swift_src_root/utils/build-script --dry-run --cmake %cmake --libdispatch --cross-compile-hosts=android-aarch64 --skip-local-build --android --android-ndk %t/ndk/ --android-arch aarch64 2>&1 | %FileCheck %s
+# RUN: SKIP_XCODE_VERSION_CHECK=1 SWIFT_BUILD_ROOT=%t %swift_src_root/utils/build-script --dry-run --cmake %cmake --foundation --swift-testing --swift-testing-macros --install-foundation --install-swift-testing-macros --install-llvm --cross-compile-hosts=android-aarch64 --cross-compile-build-swift-tools=False --android --android-ndk %t/ndk/ --android-arch aarch64 2>&1 | %FileCheck %s
 
-# CHECK: -DCMAKE_Swift_FLAGS{{.*}}-target {{.*}}unknown-linux-android{{.*}} -sdk
-# CHECK: -DCMAKE_SYSTEM_NAME=Android {{.*}} -DCMAKE_ANDROID_NDK
+# CHECK: pushd {{.*}}/llvm-android-aarch64
+# CHECK-NOT: cmake --build {{.*}}/llvm-android-aarch64 --config
+# CHECK-NOT: cmake --build {{.*}}/llvm-android-aarch64 {{.*}} install-llvm
+# CHECK: cmake {{.*}}-DSWIFT_INCLUDE_TOOLS:BOOL=FALSE{{.*}}/swift
+# CHECK: Skipping building Foundation Macros for android-aarch64, because the host tools are not being built
+# CHECK: Skipping installing Foundation Macros for android-aarch64, because the host tools are not being built
+# CHECK: Skipping building Testing Macros for android-aarch64, because the host tools are not being built
+# CHECK: Skipping installing Testing Macros for android-aarch64, because the host tools are not being built
+# CHECK: cmake {{.*}}-DCMAKE_TOOLCHAIN_FILE:PATH={{.*}}swifttesting-android-aarch64/BuildScriptToolchain.cmake
+# CHECK: -DCMAKE_Swift_FLAGS=-target aarch64-unknown-linux-android{{.*}} -sdk
diff --git a/validation-test/BuildSystem/build_worktree.test b/validation-test/BuildSystem/build_worktree.test
index f72ffc38f0f57..1f1f7c40cbef0 100644
--- a/validation-test/BuildSystem/build_worktree.test
+++ b/validation-test/BuildSystem/build_worktree.test
@@ -12,7 +12,7 @@
 # RUN: git -C %t/swift worktree add --detach %t/swift-worktree
 
 # Invoke the build script from the worktree.
-# RUN: %t/swift-worktree/utils/build-script --dry-run | %FileCheck -DARCH=%target-arch %s
+# RUN: %t/swift-worktree/utils/build-script --dry-run --cmake %cmake | %FileCheck -DARCH=%target-arch %s
 
 # We should generate a build system for the linked worktree, not the main
 # worktree.
diff --git a/validation-test/BuildSystem/cmark_crosscompile_using_toolchain_always.test b/validation-test/BuildSystem/cmark_crosscompile_using_toolchain_always.test
index 25dbee7709ea1..d546a591a673c 100644
--- a/validation-test/BuildSystem/cmark_crosscompile_using_toolchain_always.test
+++ b/validation-test/BuildSystem/cmark_crosscompile_using_toolchain_always.test
@@ -1,9 +1,15 @@
+# XFAIL: OS=freebsd
+
 # REQUIRES: standalone_build
-# REQUIRES: OS=macosx
 
 # RUN: %empty-directory(%t)
 # RUN: mkdir -p %t
 # RUN: SKIP_XCODE_VERSION_CHECK=1 SWIFT_BUILD_ROOT=%t %swift_src_root/utils/build-script --dry-run --install-all --cmake %cmake --skip-build-llvm --skip-build-swift 2>&1 | %FileCheck %s
+# RUN: SKIP_XCODE_VERSION_CHECK=1 SWIFT_BUILD_ROOT=%t %swift_src_root/utils/build-script --dry-run --install-all --cmake %cmake --skip-build-llvm --skip-build-swift --cross-compile-hosts=android-aarch64 --skip-local-build --android --android-ndk %t/ndk/ 2>&1 | %FileCheck --check-prefix=ANDROID %s
 
 # CHECK: DRY_RUN! Writing Toolchain file to path:{{.*}}BuildScriptToolchain.cmake
 # CHECK: cmake {{.*}}-DCMAKE_TOOLCHAIN_FILE:PATH={{.*}}BuildScriptToolchain.cmake {{.*}}cmark
+
+# ANDROID: DRY_RUN! Writing Toolchain file to path:{{.*}}cmark-android-aarch64/BuildScriptToolchain.cmake
+# ANDROID: cmake {{.*}}-DCMAKE_TOOLCHAIN_FILE:PATH={{.*}}cmark-android-aarch64/BuildScriptToolchain.cmake
+# ANDROID: -DCMAKE_Swift_FLAGS=-target aarch64-unknown-linux-android
diff --git a/validation-test/BuildSystem/llvm-build-compiler-rt-on-linux.test b/validation-test/BuildSystem/llvm-build-compiler-rt-on-linux.test
new file mode 100644
index 0000000000000..3db4ecc15e601
--- /dev/null
+++ b/validation-test/BuildSystem/llvm-build-compiler-rt-on-linux.test
@@ -0,0 +1,11 @@
+# REQUIRES: standalone_build
+# REQUIRES: OS=linux-gnu
+
+# RUN: %empty-directory(%t)
+# RUN: SKIP_XCODE_VERSION_CHECK=1 SWIFT_BUILD_ROOT=%t %swift_src_root/utils/build-script --dry-run --skip-build --cmake %cmake  2>&1 | %FileCheck --check-prefix=LINUX %s
+
+# LINUX: Building llvm
+# LINUX-DAG: cmake -G Ninja
+# LINUX-SAME: -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR{{[^ ]*}}=OFF
+# LINUX-SAME: -DSANITIZER_COMMON_LINK_FLAGS{{[^ ]*}}=-Wl,-z,undefs
+# LINUX-SAME: llvm
diff --git a/validation-test/BuildSystem/llvm-build-compiler-rt-on-macosx.test b/validation-test/BuildSystem/llvm-build-compiler-rt-on-macosx.test
new file mode 100644
index 0000000000000..b72da145982f1
--- /dev/null
+++ b/validation-test/BuildSystem/llvm-build-compiler-rt-on-macosx.test
@@ -0,0 +1,16 @@
+# REQUIRES: standalone_build
+# REQUIRES: OS=macosx
+
+# RUN: %empty-directory(%t)
+# RUN: SKIP_XCODE_VERSION_CHECK=1 SWIFT_BUILD_ROOT=%t %swift_src_root/utils/build-script --dry-run --skip-build --cmake %cmake  2>&1 | %FileCheck --check-prefix=LLVM-USE-RUNTIMES %s
+
+# LLVM-USE-RUNTIMES: Building llvm
+# LLVM-USE-RUNTIMES-DAG: cmake -G Ninja
+# LLVM-USE-RUNTIMES-SAME: -DBUILTINS_{{[^ ]*}}_CMAKE_OSX_SYSROOT
+# LLVM-USE-RUNTIMES-SAME: -DRUNTIMES_{{[^ ]*}}_CMAKE_OSX_SYSROOT
+# LLVM-USE-RUNTIMES-SAME: -DLLVM_BUILTIN_TARGETS
+# LLVM-USE-RUNTIMES-SAME: -DLLVM_RUNTIME_TARGETS
+# LLVM-USE-RUNTIMES-SAME: -DRUNTIMES_{{[^ ]*}}_COMPILER_RT_SANITIZERS_TO_BUILD
+# LLVM-USE-RUNTIMES-NOT: rtsan
+# LLVM-USE-RUNTIMES-SAME: -DBUILTINS_{{[^ ]*}}_COMPILER_RT_FORCE_BUILD_BAREMETAL_MACHO_BUILTINS_ARCHS
+# LLVM-USE-RUNTIMES-SAME: llvm
diff --git a/validation-test/BuildSystem/llvm-build-compiler-rt-with-use-runtimes.test b/validation-test/BuildSystem/llvm-build-compiler-rt-with-use-runtimes.test
new file mode 100644
index 0000000000000..4b23bb2bbeb90
--- /dev/null
+++ b/validation-test/BuildSystem/llvm-build-compiler-rt-with-use-runtimes.test
@@ -0,0 +1,21 @@
+# REQUIRES: standalone_build
+
+# RUN: %empty-directory(%t)
+# RUN: SKIP_XCODE_VERSION_CHECK=1 SWIFT_BUILD_ROOT=%t %swift_src_root/utils/build-script --dry-run --skip-build --cmake %cmake  2>&1 | %FileCheck --check-prefix=LLVM-USE-RUNTIMES %s
+
+# LLVM-USE-RUNTIMES: Building llvm
+# LLVM-USE-RUNTIMES-DAG: cmake -G Ninja
+# LLVM-USE-RUNTIMES-SAME: -ULLVM_TOOL_COMPILER_RT_BUILD
+# LLVM-USE-RUNTIMES-SAME: -ULLVM_BUILD_EXTERNAL_COMPILER_RT
+# LLVM-USE-RUNTIMES-SAME: -DLLVM_ENABLE_RUNTIMES{{[^ ]*}}={{[^ ]*}}compiler-rt
+# LLVM-USE-RUNTIMES-SAME: llvm{{$}}
+
+# RUN: %empty-directory(%t)
+# RUN: SKIP_XCODE_VERSION_CHECK=1 SWIFT_BUILD_ROOT=%t %swift_src_root/utils/build-script --dry-run --skip-build --skip-build-compiler-rt --cmake %cmake  2>&1 | %FileCheck --check-prefix=DONT-BUILD-COMPILER-RT %s
+
+# DONT-BUILD-COMPILER-RT: Building llvm
+# DONT-BUILD-COMPILER-RT-DAG: cmake -G Ninja
+# DONT-BUILD-COMPILER-RT-SAME: -ULLVM_TOOL_COMPILER_RT_BUILD
+# DONT-BUILD-COMPILER-RT-SAME: -ULLVM_BUILD_EXTERNAL_COMPILER_RT
+# DONT-BUILD-COMPILER-RT-NOT: -DLLVM_ENABLE_RUNTIMES{{[^ ]*}}={{[^ ]*}}compiler-rt
+# DONT-BUILD-COMPILER-RT-SAME: llvm{{$}}
diff --git a/validation-test/BuildSystem/swift-xcodegen.test b/validation-test/BuildSystem/swift-xcodegen.test
index 989740f6917be..935039931d233 100644
--- a/validation-test/BuildSystem/swift-xcodegen.test
+++ b/validation-test/BuildSystem/swift-xcodegen.test
@@ -12,17 +12,16 @@
 # First copy swift-xcodegen to the temporary location
 # so we don't touch the user's build, and make sure
 # we're doing a clean build.
-# RUN: cp -r %swift_src_root/utils/swift-xcodegen %t/src/swift/utils/swift-xcodegen
+# RUN: cp -R %swift_src_root/utils/swift-xcodegen %t/src/swift/utils/swift-xcodegen
 # RUN: rm -rf %t/src/swift/utils/swift-xcodegen/.build
 
 # Add symlinks for local dependencies
 # RUN: ln -s %swift_src_root/../swift-* %t/src
 # RUN: ln -s %swift_src_root/../llbuild %t/src
-# RUN: ln -s %swift_src_root/../yams %t/src
 
 # Run the xcodegen test suite
-# RUN: xcrun swift-test --package-path %t/src/swift/utils/swift-xcodegen
+# RUN: xcrun swift-test -c release --disable-dependency-cache --package-path %t/src/swift/utils/swift-xcodegen
 
 # Then check to see that xcodegen can generate a project successfully
-# RUN: xcrun swift-run --package-path %t/src/swift/utils/swift-xcodegen swift-xcodegen --project-root-dir %swift_src_root/.. --output-dir %t/out %swift_obj_root/..
+# RUN: xcrun swift-run -c release --disable-dependency-cache --skip-build --package-path %t/src/swift/utils/swift-xcodegen swift-xcodegen --project-root-dir %swift_src_root/.. --output-dir %t/out %swift_obj_root/..
 # RUN: ls %t/out/Swift.xcodeproj > /dev/null
diff --git a/validation-test/Concurrency/rdar107275872.swift b/validation-test/Concurrency/rdar107275872.swift
index fd56f6970a30c..8f9a54cb8b9b7 100644
--- a/validation-test/Concurrency/rdar107275872.swift
+++ b/validation-test/Concurrency/rdar107275872.swift
@@ -7,6 +7,7 @@
 // REQUIRES: concurrency
 // REQUIRES: executable_test
 // REQUIRES: concurrency_runtime
+// UNSUPPORTED: back_deployment_runtime || use_os_stdlib
 
 // rdar://108260399
 // REQUIRES: optimized_stdlib
diff --git a/validation-test/Driver/batch_mode_size_limit.swift b/validation-test/Driver/batch_mode_size_limit.swift
deleted file mode 100644
index 4ca7918958460..0000000000000
--- a/validation-test/Driver/batch_mode_size_limit.swift
+++ /dev/null
@@ -1,76 +0,0 @@
-// When -enable-only-one-dependency-file (which is the default) the one compile job with the dependency output is unbatchable.
-
-// RUN: %empty-directory(%t)
-// RUN: touch  %t/f_1_1.swift %t/f_1_2.swift %t/f_1_3.swift %t/f_1_4.swift %t/f_1_5.swift %t/f_1_6.swift %t/f_1_7.swift %t/f_1_8.swift %t/f_1_9.swift %t/f_1_10.swift
-// RUN: touch  %t/f_2_1.swift %t/f_2_2.swift %t/f_2_3.swift %t/f_2_4.swift %t/f_2_5.swift %t/f_2_6.swift %t/f_2_7.swift %t/f_2_8.swift %t/f_2_9.swift %t/f_2_10.swift
-// RUN: touch  %t/f_3_1.swift %t/f_3_2.swift %t/f_3_3.swift %t/f_3_4.swift %t/f_3_5.swift %t/f_3_6.swift %t/f_3_7.swift %t/f_3_8.swift %t/f_3_9.swift %t/f_3_10.swift
-// RUN: touch  %t/f_4_1.swift %t/f_4_2.swift %t/f_4_3.swift %t/f_4_4.swift %t/f_4_5.swift %t/f_4_6.swift %t/f_4_7.swift %t/f_4_8.swift %t/f_4_9.swift %t/f_4_10.swift
-// RUN: touch  %t/f_5_1.swift %t/f_5_2.swift %t/f_5_3.swift %t/f_5_4.swift %t/f_5_5.swift %t/f_5_6.swift %t/f_5_7.swift %t/f_5_8.swift %t/f_5_9.swift %t/f_5_10.swift
-// RUN: touch  %t/f_6_1.swift %t/f_6_2.swift %t/f_6_3.swift %t/f_6_4.swift %t/f_6_5.swift %t/f_6_6.swift %t/f_6_7.swift %t/f_6_8.swift %t/f_6_9.swift %t/f_6_10.swift
-// RUN: touch  %t/f_7_1.swift %t/f_7_2.swift %t/f_7_3.swift %t/f_7_4.swift %t/f_7_5.swift %t/f_7_6.swift %t/f_7_7.swift %t/f_7_8.swift %t/f_7_9.swift %t/f_7_10.swift
-// RUN: touch  %t/f_8_1.swift %t/f_8_2.swift %t/f_8_3.swift %t/f_8_4.swift %t/f_8_5.swift %t/f_8_6.swift %t/f_8_7.swift %t/f_8_8.swift %t/f_8_9.swift %t/f_8_10.swift
-// RUN: touch  %t/f_9_1.swift %t/f_9_2.swift %t/f_9_3.swift %t/f_9_4.swift %t/f_9_5.swift %t/f_9_6.swift %t/f_9_7.swift %t/f_9_8.swift %t/f_9_9.swift %t/f_9_10.swift
-// RUN: touch  %t/f_10_1.swift %t/f_10_2.swift %t/f_10_3.swift %t/f_10_4.swift %t/f_10_5.swift %t/f_10_6.swift %t/f_10_7.swift %t/f_10_8.swift %t/f_10_9.swift %t/f_10_10.swift
-// RUN: %swiftc_driver -disable-only-one-dependency-file -driver-show-job-lifecycle -v -c -module-name foo -emit-module -serialize-diagnostics -emit-dependencies -j 1 -enable-batch-mode %t/f_*.swift >%t/out.txt  2>&1
-
-// RUN: %FileCheck %s -check-prefix=CHECK-DIS <%t/out.txt
-// CHECK-DIS-NOT: unable to execute command
-// CHECK-DIS: Forming into 4 batches
-// CHECK-DIS-DAG: Forming batch job from 25 constituents
-// CHECK-DIS-DAG: Forming batch job from 25 constituents
-// CHECK-DIS-DAG: Forming batch job from 25 constituents
-// CHECK-DIS-DAG: Forming batch job from 25 constituents
-
-
-// RUN: %swiftc_driver -disable-only-one-dependency-file -driver-show-job-lifecycle -driver-batch-size-limit 10 -v -c -module-name foo -emit-module -serialize-diagnostics -emit-dependencies -j 1 -enable-batch-mode %t/f_*.swift >%t/out2.txt 2>&1
-// RUN: %FileCheck %s <%t/out2.txt -check-prefix=EXPLICIT-ARG-DIS
-// EXPLICIT-ARG-DIS-NOT: unable to execute command
-// EXPLICIT-ARG-DIS: Forming into 10 batches
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-DIS-DAG: Forming batch job from 10 constituents
-
-
-// When -enable-only-one-dependency-file (which is the default) the one compile job with the dependency output is unbatchable.
-
-// RUN: %empty-directory(%t)
-// RUN: touch  %t/f_1_1.swift %t/f_1_2.swift %t/f_1_3.swift %t/f_1_4.swift %t/f_1_5.swift %t/f_1_6.swift %t/f_1_7.swift %t/f_1_8.swift %t/f_1_9.swift %t/f_1_10.swift
-// RUN: touch  %t/f_2_1.swift %t/f_2_2.swift %t/f_2_3.swift %t/f_2_4.swift %t/f_2_5.swift %t/f_2_6.swift %t/f_2_7.swift %t/f_2_8.swift %t/f_2_9.swift %t/f_2_10.swift
-// RUN: touch  %t/f_3_1.swift %t/f_3_2.swift %t/f_3_3.swift %t/f_3_4.swift %t/f_3_5.swift %t/f_3_6.swift %t/f_3_7.swift %t/f_3_8.swift %t/f_3_9.swift %t/f_3_10.swift
-// RUN: touch  %t/f_4_1.swift %t/f_4_2.swift %t/f_4_3.swift %t/f_4_4.swift %t/f_4_5.swift %t/f_4_6.swift %t/f_4_7.swift %t/f_4_8.swift %t/f_4_9.swift %t/f_4_10.swift
-// RUN: touch  %t/f_5_1.swift %t/f_5_2.swift %t/f_5_3.swift %t/f_5_4.swift %t/f_5_5.swift %t/f_5_6.swift %t/f_5_7.swift %t/f_5_8.swift %t/f_5_9.swift %t/f_5_10.swift
-// RUN: touch  %t/f_6_1.swift %t/f_6_2.swift %t/f_6_3.swift %t/f_6_4.swift %t/f_6_5.swift %t/f_6_6.swift %t/f_6_7.swift %t/f_6_8.swift %t/f_6_9.swift %t/f_6_10.swift
-// RUN: touch  %t/f_7_1.swift %t/f_7_2.swift %t/f_7_3.swift %t/f_7_4.swift %t/f_7_5.swift %t/f_7_6.swift %t/f_7_7.swift %t/f_7_8.swift %t/f_7_9.swift %t/f_7_10.swift
-// RUN: touch  %t/f_8_1.swift %t/f_8_2.swift %t/f_8_3.swift %t/f_8_4.swift %t/f_8_5.swift %t/f_8_6.swift %t/f_8_7.swift %t/f_8_8.swift %t/f_8_9.swift %t/f_8_10.swift
-// RUN: touch  %t/f_9_1.swift %t/f_9_2.swift %t/f_9_3.swift %t/f_9_4.swift %t/f_9_5.swift %t/f_9_6.swift %t/f_9_7.swift %t/f_9_8.swift %t/f_9_9.swift %t/f_9_10.swift
-// RUN: touch  %t/f_10_1.swift %t/f_10_2.swift %t/f_10_3.swift %t/f_10_4.swift %t/f_10_5.swift %t/f_10_6.swift %t/f_10_7.swift %t/f_10_8.swift %t/f_10_9.swift %t/f_10_10.swift
-// RUN: %swiftc_driver -enable-only-one-dependency-file -driver-show-job-lifecycle -v -c -module-name foo -emit-module -serialize-diagnostics -emit-dependencies -j 1 -enable-batch-mode %t/f_*.swift >%t/out.txt 2>&1
-// RUN: %FileCheck %s -check-prefix=CHECK-ENA <%t/out.txt
-// CHECK-ENA-NOT: unable to execute command
-// CHECK-ENA: Forming into 4 batches
-// CHECK-ENA-DAG: Forming batch job from 25 constituents
-// CHECK-ENA-DAG: Forming batch job from 25 constituents
-// CHECK-ENA-DAG: Forming batch job from 25 constituents
-// CHECK-ENA-DAG: Forming batch job from 24 constituents
-//
-// RUN: %swiftc_driver -enable-only-one-dependency-file -driver-show-job-lifecycle -driver-batch-size-limit 10 -v -c -module-name foo -emit-module -serialize-diagnostics -emit-dependencies -j 1 -enable-batch-mode %t/f_*.swift >%t/out2.txt 2>&1
-// RUN: %FileCheck %s <%t/out2.txt -check-prefix=EXPLICIT-ARG-ENA
-// EXPLICIT-ARG-ENA-NOT: unable to execute command
-// EXPLICIT-ARG-ENA: Forming into 10 batches
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 10 constituents
-// EXPLICIT-ARG-ENA-DAG: Forming batch job from 9 constituents
diff --git a/validation-test/IDE/complete_from_cocoa.swift b/validation-test/IDE/complete_from_cocoa.swift
index 10deae5186869..fbe68a3854436 100644
--- a/validation-test/IDE/complete_from_cocoa.swift
+++ b/validation-test/IDE/complete_from_cocoa.swift
@@ -1,4 +1,5 @@
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=T1 | %FileCheck %s -check-prefix=T1
+// FIXME: Reenable USR verification (rdar://159844268)
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=T1 -code-completion-verify-usr-to-decl=false | %FileCheck %s -check-prefix=T1
 
 // REQUIRES: objc_interop
 // REQUIRES: no_asan
diff --git a/validation-test/IDE/complete_from_cocoa_2.swift b/validation-test/IDE/complete_from_cocoa_2.swift
index 48cf98d64aedd..f93ea073d9150 100644
--- a/validation-test/IDE/complete_from_cocoa_2.swift
+++ b/validation-test/IDE/complete_from_cocoa_2.swift
@@ -1,5 +1,6 @@
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=T1 | %FileCheck %s -check-prefix=T1
-// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=T2 | %FileCheck %s -check-prefix=T2
+// FIXME: Reenable USR verification (rdar://159844268)
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=T1 -code-completion-verify-usr-to-decl=false | %FileCheck %s -check-prefix=T1
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=T2 -code-completion-verify-usr-to-decl=false | %FileCheck %s -check-prefix=T2
 
 // REQUIRES: objc_interop
 
diff --git a/validation-test/IDE/complete_sdk_platform.swift b/validation-test/IDE/complete_sdk_platform.swift
index 5b23f5111ae71..adcb2ce3ceddd 100644
--- a/validation-test/IDE/complete_sdk_platform.swift
+++ b/validation-test/IDE/complete_sdk_platform.swift
@@ -1,10 +1,11 @@
 // RUN: %empty-directory(%t)
 // RUN: ln -s %sdk %t/sdk
 
-// RUN: %batch-code-completion %xcode-extra-platform-search-paths
+// FIXME: Reenable USR verification (rdar://159844268)
+// RUN: %batch-code-completion %xcode-extra-platform-search-paths -code-completion-verify-usr-to-decl=false
 
 // Works if SDK is specified as a symlink too.
-// RUN: %batch-code-completion -sdk %t/sdk %xcode-extra-platform-search-paths
+// RUN: %batch-code-completion -sdk %t/sdk %xcode-extra-platform-search-paths -code-completion-verify-usr-to-decl=false
 
 // REQUIRES: OS=macosx
 // rdar://131854240 - Make sure modules found in the platform dir are treated
diff --git a/validation-test/IDE/crashers/000798f041dcc07b.swift b/validation-test/IDE/crashers/000798f041dcc07b.swift
new file mode 100644
index 0000000000000..dafbd7910b6dd
--- /dev/null
+++ b/validation-test/IDE/crashers/000798f041dcc07b.swift
@@ -0,0 +1,12 @@
+// {"kind":"complete","signature":"swift::constraints::ConstraintSystem::addKeyPathApplicationRootConstraint(swift::Type, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: ((path.size() == 1 && path[0].getKind() == ConstraintLocator::SubscriptMember) || (path.size() == 2 && path[1].getKind() == ConstraintLocator::KeyPathDynamicMember)), function addKeyPathApplicationRootConstraint"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a {
+  @dynamicMemberLookup enum b {
+    subscript <c>(dynamicMember d: KeyPath<a, c>) -> c {
+      @dynamicMemberLookup class e {c { self[
+#^COMPLETE^#}
+        subscript(dynamicMember d: KeyPath<b, c>) -> c
+      }
+    }
+  }
+}
diff --git a/validation-test/IDE/crashers/06ac15e9391fc736.swift b/validation-test/IDE/crashers/06ac15e9391fc736.swift
new file mode 100644
index 0000000000000..42826ff73f3c1
--- /dev/null
+++ b/validation-test/IDE/crashers/06ac15e9391fc736.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"4be98c4c","signature":"swift::Parser::consumeDecl(swift::ParserPosition, bool)","signatureAssert":"Assertion failed: (!IDEInspectionDelayedDeclStat.get() && \"only one decl can be delayed for code completion\"), function setIDEInspectionDelayedDeclState"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+case /if { class a{ #^^#<#expression#>
diff --git a/validation-test/IDE/crashers/09a6a167b9c9fe2e.swift b/validation-test/IDE/crashers/09a6a167b9c9fe2e.swift
new file mode 100644
index 0000000000000..17677916aeb48
--- /dev/null
+++ b/validation-test/IDE/crashers/09a6a167b9c9fe2e.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::ide::CodeCompletionStringBuilder::addCallArgumentPatterns(llvm::ArrayRef<swift::AnyFunctionType::Param>, llvm::ArrayRef<swift::ParamDecl const*>, swift::DeclContext const*, swift::GenericSignature, swift::ide::DefaultArgumentOutputMode, bool)","signatureAssert":"Assertion failed: (declParams.empty() || typeParams.size() == declParams.size()), function addCallArgumentPatterns"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func a<each b>( repeat each b)c == a(
+#^COMPLETE^# d
diff --git a/validation-test/IDE/crashers/0af7ab3606b78927.swift b/validation-test/IDE/crashers/0af7ab3606b78927.swift
new file mode 100644
index 0000000000000..c406272220ce4
--- /dev/null
+++ b/validation-test/IDE/crashers/0af7ab3606b78927.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"33e6423a","signature":"swift::printContext(llvm::raw_ostream&, swift::DeclContext*)"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension {
+  subscript -> {
+    @
+    #^^#
diff --git a/validation-test/IDE/crashers/0c65ac26afb25b40.swift b/validation-test/IDE/crashers/0c65ac26afb25b40.swift
new file mode 100644
index 0000000000000..3285504c35563
--- /dev/null
+++ b/validation-test/IDE/crashers/0c65ac26afb25b40.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::Parser::parseStorageRestrictionsAttribute(swift::SourceLoc, swift::SourceLoc)","signatureAssert":"Assertion failed: (Start.isValid() == End.isValid() && \"Start and end should either both be valid or both be invalid!\"), function SourceRange"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{ #^COMPLETE^#@storageRestrictions(
diff --git a/validation-test/IDE/crashers/0dfb0607ca6550ec.swift b/validation-test/IDE/crashers/0dfb0607ca6550ec.swift
new file mode 100644
index 0000000000000..c78c7e07cde8e
--- /dev/null
+++ b/validation-test/IDE/crashers/0dfb0607ca6550ec.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"002a4f4b","signature":"swift::PrintingDiagnosticConsumer::printDiagnostic(swift::SourceManager&, swift::DiagnosticInfo const&)","signatureAssert":"Assertion failed: ((size_t)sys::locale::columnWidth(Fixit.getText()) == Fixit.getText().size()), function buildFixItLine"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func b<c where #^^# == <#type#>>(a: <#type#>)
diff --git a/validation-test/IDE/crashers/0ee20e8624ac46fa.swift b/validation-test/IDE/crashers/0ee20e8624ac46fa.swift
new file mode 100644
index 0000000000000..becf9284e7715
--- /dev/null
+++ b/validation-test/IDE/crashers/0ee20e8624ac46fa.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"0057cadb","signature":"(anonymous namespace)::CodeCompletionCallbacksImpl::typecheckParsedType()","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{class a<b where b#^^#
diff --git a/validation-test/IDE/crashers/102203dd7c9d004e.swift b/validation-test/IDE/crashers/102203dd7c9d004e.swift
new file mode 100644
index 0000000000000..96a0fea1582fb
--- /dev/null
+++ b/validation-test/IDE/crashers/102203dd7c9d004e.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","signature":"swift::IterableDeclContext::addMemberSilently(swift::Decl*, swift::Decl*, bool) const","signatureAssert":"Assertion failed: (hint == nullptr), function addMemberSilently"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{
+  class a {
+    lazy b: = #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/10b243ac3f1f8d7b.swift b/validation-test/IDE/crashers/10b243ac3f1f8d7b.swift
new file mode 100644
index 0000000000000..ac861aa0e24e9
--- /dev/null
+++ b/validation-test/IDE/crashers/10b243ac3f1f8d7b.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","signature":"swift::TypeChecker::resolveDeclRefExpr(swift::UnresolvedDeclRefExpr*, swift::DeclContext*)","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension <#type#> {
+  var
+  a = "title \( init String * 0).General\(String#^COMPLETE^#0))"
+}
diff --git a/validation-test/IDE/crashers/113aa5cad622a515.swift b/validation-test/IDE/crashers/113aa5cad622a515.swift
new file mode 100644
index 0000000000000..345d98b74452d
--- /dev/null
+++ b/validation-test/IDE/crashers/113aa5cad622a515.swift
@@ -0,0 +1,9 @@
+// {"kind":"complete","original":"3a7f38eb","signature":"swift::Mangle::ASTMangler::appendType(swift::Type, swift::GenericSignature, swift::ValueDecl const*)","signatureAssert":"Assertion failed: (paramTy->isCanonical() && \"cannot mangle non-canonical generic parameter\"), function appendType"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a<b> {
+  func
+    c<let d: b>()
+  {
+    #^^#
+  }
+}
diff --git a/validation-test/IDE/crashers/16a3fafef684fb37.swift b/validation-test/IDE/crashers/16a3fafef684fb37.swift
new file mode 100644
index 0000000000000..4975470400104
--- /dev/null
+++ b/validation-test/IDE/crashers/16a3fafef684fb37.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"6bce2476","signature":"swift::ide::PostfixCompletionCallback::sawSolutionImpl(swift::constraints::Solution const&)","signatureAssert":"Assertion failed: (BaseIsStaticMetaType == Other.BaseIsStaticMetaType), function tryMerge"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension BinaryInteger {
+a { .Iterator.Element#^^# ==
+self
diff --git a/validation-test/IDE/crashers/1a97a715994667ab.swift b/validation-test/IDE/crashers/1a97a715994667ab.swift
new file mode 100644
index 0000000000000..a8b10f008bb19
--- /dev/null
+++ b/validation-test/IDE/crashers/1a97a715994667ab.swift
@@ -0,0 +1,9 @@
+// {"kind":"complete","original":"2d0bf5d7","signature":"swift::constraints::ConstraintSystem::getTypeOfReferencePre(swift::constraints::OverloadChoice, swift::DeclContext*, swift::constraints::ConstraintLocatorBuilder, swift::constraints::PreparedOverloadBuilder*)","signatureAssert":"Assertion failed: (!valueType->hasUnboundGenericType() && !valueType->hasTypeParameter()), function getTypeOfReferencePre"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{ (a: Dictionary) in
+  #^^#
+  let b = a {
+    b
+  }
+  let b
+}
diff --git a/validation-test/IDE/crashers/1ac322cbf002c111.swift b/validation-test/IDE/crashers/1ac322cbf002c111.swift
new file mode 100644
index 0000000000000..32c702306e849
--- /dev/null
+++ b/validation-test/IDE/crashers/1ac322cbf002c111.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","signature":"swift::IterableDeclContext::addMemberSilently(swift::Decl*, swift::Decl*, bool) const::$_0::operator()(swift::Decl*, swift::Decl*) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a {b { { [ } ] in
+#^COMPLETE^#
+}
+c)
diff --git a/validation-test/IDE/crashers/1c86dd91fb8483fc.swift b/validation-test/IDE/crashers/1c86dd91fb8483fc.swift
new file mode 100644
index 0000000000000..edbedf789db26
--- /dev/null
+++ b/validation-test/IDE/crashers/1c86dd91fb8483fc.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"070481b6","signature":"swift::Mangle::ASTMangler::appendEntity(swift::ValueDecl const*)","signatureAssert":"Assertion failed: (!isa<ConstructorDecl>(decl)), function appendEntity"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@abi( init () ) func a
+#^^#()
diff --git a/validation-test/IDE/crashers/1e4621d80984121a.swift b/validation-test/IDE/crashers/1e4621d80984121a.swift
new file mode 100644
index 0000000000000..54e28f76afc3d
--- /dev/null
+++ b/validation-test/IDE/crashers/1e4621d80984121a.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"3a52f860","signature":"swift::TypeChecker::resolveDeclRefExpr(swift::UnresolvedDeclRefExpr*, swift::DeclContext*)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension Sequence where a == b [ { func c { map#^^#
diff --git a/validation-test/IDE/crashers/1f12cff3151ffd0f.swift b/validation-test/IDE/crashers/1f12cff3151ffd0f.swift
new file mode 100644
index 0000000000000..3cd0d4ed79121
--- /dev/null
+++ b/validation-test/IDE/crashers/1f12cff3151ffd0f.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","original":"0116e8cd","signature":"swift::ConformanceChecker::resolveWitnessViaLookup(swift::ValueDecl*)","signatureAssert":"Assertion failed: (Conformance->getWitnessUncached(requirement).getDecl() == match.Witness && \"Deduced different witnesses?\"), function recordWitness"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a: OptionSet {
+  static rawValue = a init(rawValue: Int ) {
+    #^^#
+  }
+}
diff --git a/validation-test/IDE/crashers/26ba10dc4c4e7f04.swift b/validation-test/IDE/crashers/26ba10dc4c4e7f04.swift
new file mode 100644
index 0000000000000..1b11697e62137
--- /dev/null
+++ b/validation-test/IDE/crashers/26ba10dc4c4e7f04.swift
@@ -0,0 +1,10 @@
+// {"kind":"complete","original":"9af9ff34","signature":"swift::InterfaceTypeRequest::cacheResult(swift::Type) const","signatureAssert":"Assertion failed: (!type->is<InOutType>() && \"Interface type must be materializable\"), function cacheResult"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+[
+  [
+    #^^#
+  ].reduce(
+    [:][0] {
+      $a, b in
+    })
+]
diff --git a/validation-test/IDE/crashers/276e1958e5b2f36f.swift b/validation-test/IDE/crashers/276e1958e5b2f36f.swift
new file mode 100644
index 0000000000000..76c140c2faf9c
--- /dev/null
+++ b/validation-test/IDE/crashers/276e1958e5b2f36f.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"14893775","signature":"swift::TypeResolution::resolveContextualType(swift::TypeRepr*, swift::DeclContext*, swift::GenericSignature, swift::TypeResolutionOptions, llvm::function_ref<swift::Type (swift::UnboundGenericType*)>, llvm::function_ref<swift::Type (swift::ASTContext&, swift::PlaceholderTypeRepr*)>, llvm::function_ref<swift::Type (swift::Type, swift::PackElementTypeRepr*)>, llvm::function_ref<void (swift::GenericTypeDecl*, llvm::function_ref<swift::Type (swift::SubstitutableType*)>)>, swift::SILTypeResolutionContext*)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@a(
+  #^^#) func b<a>()
diff --git a/validation-test/IDE/crashers/27fbd118920a31ee.swift b/validation-test/IDE/crashers/27fbd118920a31ee.swift
new file mode 100644
index 0000000000000..96092cdd1560f
--- /dev/null
+++ b/validation-test/IDE/crashers/27fbd118920a31ee.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"(anonymous namespace)::getEquivalentDeclContextFromSourceFile(swift::DeclContext*, swift::SourceFile*)"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+do { func a { #^^# #^b^#
diff --git a/validation-test/IDE/crashers/2ac01e09917bfde5.swift b/validation-test/IDE/crashers/2ac01e09917bfde5.swift
new file mode 100644
index 0000000000000..947ae8416e966
--- /dev/null
+++ b/validation-test/IDE/crashers/2ac01e09917bfde5.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"eb071a3e","signature":"swift::constraints::ConstraintSystem::isArgumentGenericFunction(swift::Type, swift::Expr*)","signatureAssert":"Assertion failed: (!getFixedType(tyvar)), function getUnboundBindOverloadDisjunction"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func a() -> Sequence
+a() + #^^#&
diff --git a/validation-test/IDE/crashers/2b1c3dd8eaf10b69.swift b/validation-test/IDE/crashers/2b1c3dd8eaf10b69.swift
new file mode 100644
index 0000000000000..3bfdc06ddb82c
--- /dev/null
+++ b/validation-test/IDE/crashers/2b1c3dd8eaf10b69.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","signature":"swift::ide::IDEInspectionInstance::performCachedOperationIfPossible(llvm::hash_code, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, swift::SearchPathOptions const&, llvm::MemoryBuffer*, unsigned int, swift::DiagnosticConsumer*, std::__1::shared_ptr<std::__1::atomic<bool>>, llvm::function_ref<void (swift::ide::CancellableResult<swift::ide::IDEInspectionInstanceResult>)>)","signatureAssert":"Assertion failed: (reparsedState->hasIDEInspectionDelayedDeclState() && \"Didn't find IDE inspection point?\"), function performCachedOperationIfPossible","useSourceOrderCompletion":true}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-order-completion -source-filename %s
+#^^#
+#if a)#^COMPLETE3^#
+var
diff --git a/validation-test/IDE/crashers/2f87241457a28443.swift b/validation-test/IDE/crashers/2f87241457a28443.swift
new file mode 100644
index 0000000000000..270444b0356f5
--- /dev/null
+++ b/validation-test/IDE/crashers/2f87241457a28443.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"1615843d","signature":"(anonymous namespace)::TypePrinter::printParentType(swift::Type)","signatureAssert":"Assertion failed: (!hasTypeParameter() && \"already have an interface type\"), function mapTypeOutOfContext"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a<b class c<b , e : a<b>> { class d let builder = d#^^#
diff --git a/validation-test/IDE/crashers/32fa0d633e8df376.swift b/validation-test/IDE/crashers/32fa0d633e8df376.swift
new file mode 100644
index 0000000000000..cf8957d54f020
--- /dev/null
+++ b/validation-test/IDE/crashers/32fa0d633e8df376.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"95ab8e45","signature":"(anonymous namespace)::TypeResolver::resolveVarargType(swift::VarargTypeRepr*, swift::TypeResolutionOptions)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a<b
+  protocol c: a<Self
+... >#^^#
diff --git a/validation-test/IDE/crashers/34e0183b6c0eafde.swift b/validation-test/IDE/crashers/34e0183b6c0eafde.swift
new file mode 100644
index 0000000000000..b17ff977081be
--- /dev/null
+++ b/validation-test/IDE/crashers/34e0183b6c0eafde.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::ast_scope::ASTScopeImpl::getCharSourceRangeOfScope(swift::SourceManager&, bool) const","signatureAssert":"Assertion failed: ((range.isValid()) && \"scope has invalid source range\"), function getCharSourceRangeOfScope"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+var a: b {
+  @ #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/3840b5540c4b70be.swift b/validation-test/IDE/crashers/3840b5540c4b70be.swift
new file mode 100644
index 0000000000000..22ac88821cda1
--- /dev/null
+++ b/validation-test/IDE/crashers/3840b5540c4b70be.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"c2850df8","signature":"swift::ValueDecl::dumpRef(llvm::raw_ostream&) const","signatureAssert":"Assertion failed: (ext->canNeverBeBound() && \"Should have been bound by bindExtensions\"), function evaluate"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@abi(
+  extension { # a(#^^#<#declaration#>)
+  <#declaration#>
diff --git a/validation-test/IDE/crashers/39b75bd7c88ae4eb.swift b/validation-test/IDE/crashers/39b75bd7c88ae4eb.swift
new file mode 100644
index 0000000000000..ebb05e8962c32
--- /dev/null
+++ b/validation-test/IDE/crashers/39b75bd7c88ae4eb.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"2b4a2fce","signature":"swift::constraints::ConstraintSystem::setClosureType(swift::ClosureExpr const*, swift::FunctionType*)","signatureAssert":"Assertion failed: (type), function setClosureType"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+a(
+  #^^# {
+    ( ()) in
diff --git a/validation-test/IDE/crashers/39e1947ce3bd2206.swift b/validation-test/IDE/crashers/39e1947ce3bd2206.swift
new file mode 100644
index 0000000000000..95cf7da0ab7bb
--- /dev/null
+++ b/validation-test/IDE/crashers/39e1947ce3bd2206.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"2e29372e","signature":"swift::FragileFunctionKindRequest::evaluate(swift::Evaluator&, swift::DeclContext*) const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+if {case ( = { enum a {
+#^^#
diff --git a/validation-test/IDE/crashers/3b831ad3cd6afbc3.swift b/validation-test/IDE/crashers/3b831ad3cd6afbc3.swift
new file mode 100644
index 0000000000000..b237dc1f812dc
--- /dev/null
+++ b/validation-test/IDE/crashers/3b831ad3cd6afbc3.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","original":"119b2739","signature":"swift::constraints::ConstraintSystem::recordArgumentList(swift::constraints::ConstraintLocator*, swift::ArgumentList*)","signatureAssert":"Assertion failed: (inserted), function recordArgumentList"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+[
+  switch 0 {
+  case .a(#b): #^^#
+  }
+]
diff --git a/validation-test/IDE/crashers/3d85becf2d3300a5.swift b/validation-test/IDE/crashers/3d85becf2d3300a5.swift
new file mode 100644
index 0000000000000..728bb4b76dc9e
--- /dev/null
+++ b/validation-test/IDE/crashers/3d85becf2d3300a5.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::Parser::consumeIdentifier(swift::Identifier&, bool)","signatureAssert":"Assertion failed: (Tok.isAny(tok::identifier, tok::kw_self, tok::kw_Self)), function consumeIdentifier"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+switch { case borrowing #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/4334b05c244e77cf.swift b/validation-test/IDE/crashers/4334b05c244e77cf.swift
new file mode 100644
index 0000000000000..35e4d930ed518
--- /dev/null
+++ b/validation-test/IDE/crashers/4334b05c244e77cf.swift
@@ -0,0 +1,11 @@
+// {"kind":"complete","original":"1a6ddccd","signature":"getRequirementMachine"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a {
+  associatedtype c: a
+  var b: c
+}
+protocol d: a where c == Never
+  extension Never: d
+    extension d {
+      public( #^^#
+      b: Never
diff --git a/validation-test/IDE/crashers/43a52bf91ab5d2ee.swift b/validation-test/IDE/crashers/43a52bf91ab5d2ee.swift
new file mode 100644
index 0000000000000..e0bed6f716ce1
--- /dev/null
+++ b/validation-test/IDE/crashers/43a52bf91ab5d2ee.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"2c0990ef","signature":"swift::TypeDecl::getName() const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension {
+  a = b [ c [ #^^#
diff --git a/validation-test/IDE/crashers/44e8aa011615df18.swift b/validation-test/IDE/crashers/44e8aa011615df18.swift
new file mode 100644
index 0000000000000..c7c19e72c1f15
--- /dev/null
+++ b/validation-test/IDE/crashers/44e8aa011615df18.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"8af9696a","signature":"(anonymous namespace)::TypePrinter::printWithParensIfNotSimple(swift::Type)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+// REQUIRES: OS=macosx
+import Foundation
+var a: some NSMutableArray = a == #^^# = <#expression#>
diff --git a/validation-test/IDE/crashers/47f8163fc7f6dd32.swift b/validation-test/IDE/crashers/47f8163fc7f6dd32.swift
new file mode 100644
index 0000000000000..fd9530c4cb7ca
--- /dev/null
+++ b/validation-test/IDE/crashers/47f8163fc7f6dd32.swift
@@ -0,0 +1,8 @@
+// {"kind":"complete","original":"029049d6","signature":"swift::ide::CompletionLookup::foundDecl(swift::ValueDecl*, swift::DeclVisibilityKind, swift::DynamicLookupInfo)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct c<d {
+  var : {
+    protocol a {
+      struct e {
+    b {
+      #^^#
diff --git a/validation-test/IDE/crashers/488be7ca295930f4.swift b/validation-test/IDE/crashers/488be7ca295930f4.swift
new file mode 100644
index 0000000000000..bdbe5707b138c
--- /dev/null
+++ b/validation-test/IDE/crashers/488be7ca295930f4.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"checkSingleOverride(swift::ValueDecl*, swift::ValueDecl*)","signatureAssert":"Assertion failed: (!baseName.isSpecial() && \"Can't retrieve the identifier of a special base name\"), function getBaseIdentifier"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a { subscript(a) a { set } class b : a { override subscript(a) a {
+#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/4b1d9718b7b1335a.swift b/validation-test/IDE/crashers/4b1d9718b7b1335a.swift
new file mode 100644
index 0000000000000..cbeb88b6b07b6
--- /dev/null
+++ b/validation-test/IDE/crashers/4b1d9718b7b1335a.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"773d9dd1","signature":"swift::ProtocolConformance::getTypeWitnessAndDecl(swift::AssociatedTypeDecl*, swift::SubstOptions) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@_marker protocol a {
+  b:
+  #^^#  typealias  5
diff --git a/validation-test/IDE/crashers/4c8b4501fbe19cd6.swift b/validation-test/IDE/crashers/4c8b4501fbe19cd6.swift
new file mode 100644
index 0000000000000..de8e90be23998
--- /dev/null
+++ b/validation-test/IDE/crashers/4c8b4501fbe19cd6.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"(anonymous namespace)::PreCheckTarget::walkToExprPre(swift::Expr*)","signatureAssert":"Assertion failed: ((closure->getParent() == DC || closure->getParent()->isChildContextOf(DC)) && \"Decl context isn't correct\"), function walkToClosureExprPre"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+macro a = { #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/524e0a7a5cd78074.swift b/validation-test/IDE/crashers/524e0a7a5cd78074.swift
new file mode 100644
index 0000000000000..bb2dd5f426f54
--- /dev/null
+++ b/validation-test/IDE/crashers/524e0a7a5cd78074.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::ide::CodeCompletionResultBuilder::takeResult()"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a { extension b { struct c { struct d<e{ f { d#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/571502fc126fa3fd.swift b/validation-test/IDE/crashers/571502fc126fa3fd.swift
new file mode 100644
index 0000000000000..f31e2b1de65c7
--- /dev/null
+++ b/validation-test/IDE/crashers/571502fc126fa3fd.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::Mangle::ASTMangler::appendType(swift::Type, swift::GenericSignature, swift::ValueDecl const*)"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+// REQUIRES: OS=macosx
+import Foundation switch Foundation { case #^^#
diff --git a/validation-test/IDE/crashers/587183a047cbcead.swift b/validation-test/IDE/crashers/587183a047cbcead.swift
new file mode 100644
index 0000000000000..8c123d4056b11
--- /dev/null
+++ b/validation-test/IDE/crashers/587183a047cbcead.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","signature":"swift::FragileFunctionKindRequest::evaluate(swift::Evaluator&, swift::DeclContext*) const","signatureAssert":"Assertion failed: (VD->hasParameterList()), function evaluate"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+enum a {
+  case ( = {
+      enum b :
+        #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/64cbd48634eb9eac.swift b/validation-test/IDE/crashers/64cbd48634eb9eac.swift
new file mode 100644
index 0000000000000..399e75733673b
--- /dev/null
+++ b/validation-test/IDE/crashers/64cbd48634eb9eac.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::constraints::ConstraintSystem::getType(swift::ASTNode) const","signatureAssert":"Assertion failed: (found != NodeTypes.end() && \"Expected type to have been set!\"), function getType"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{ switch { case let c(#^COMPLETE^# b) a
diff --git a/validation-test/IDE/crashers/6e14da1a44c1cdc6.swift b/validation-test/IDE/crashers/6e14da1a44c1cdc6.swift
new file mode 100644
index 0000000000000..3dfbf9e2e56fd
--- /dev/null
+++ b/validation-test/IDE/crashers/6e14da1a44c1cdc6.swift
@@ -0,0 +1,9 @@
+// {"kind":"complete","original":"8b824012","signature":"swift::Mangle::ASTMangler::appendBoundGenericArgs(swift::DeclContext*, swift::GenericSignature, swift::SubstitutionMap, bool&, swift::ValueDecl const*)","signatureAssert":"Assertion failed: (Index < Length && \"Invalid index!\"), function operator[]"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a {
+  struct b {
+    var c: (some Any, Int) {
+      #^^#
+    }
+  }
+}
diff --git a/validation-test/IDE/crashers/724e28836dc20ecb.swift b/validation-test/IDE/crashers/724e28836dc20ecb.swift
new file mode 100644
index 0000000000000..80c4c990ea417
--- /dev/null
+++ b/validation-test/IDE/crashers/724e28836dc20ecb.swift
@@ -0,0 +1,8 @@
+// {"kind":"complete","original":"b09ce71a","signature":"swift::Decl::getResolvedCustomAttrType(swift::CustomAttr*) const","signatureAssert":"Assertion failed: (ctx.Diags.hadAnyError()), function evaluate","useSourceOrderCompletion":true}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-order-completion -source-filename %s
+struct a<b
+extension a where b == {struct c {
+@d#^^#({ #^e^#}
+var f }
+@propertyWrapper
+class d
diff --git a/validation-test/IDE/crashers/73f3b9a72697ee92.swift b/validation-test/IDE/crashers/73f3b9a72697ee92.swift
new file mode 100644
index 0000000000000..18e18dd36d541
--- /dev/null
+++ b/validation-test/IDE/crashers/73f3b9a72697ee92.swift
@@ -0,0 +1,11 @@
+// {"kind":"complete","signature":"swift::GenericSignatureImpl::isValidTypeParameter(swift::Type) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -code-completion-diagnostics -source-filename %s
+protocol a {
+  associatedtype c: a
+  var b: c
+}
+protocol d: a where c == Never
+  extension Never: d
+    extension d {
+      #^COMPLETE^# var
+      b: Never
diff --git a/validation-test/IDE/crashers/7621907bdc5958a6.swift b/validation-test/IDE/crashers/7621907bdc5958a6.swift
new file mode 100644
index 0000000000000..90c97bc85ad35
--- /dev/null
+++ b/validation-test/IDE/crashers/7621907bdc5958a6.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"526e79b6","signature":"swift::TypeChecker::checkDeclAttributes(swift::Decl*)","signatureAssert":"Assertion failed: (Ctx.hadError()), function visitCustomAttr","useSourceOrderCompletion":true}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-order-completion -source-filename %s
+#^^#
+typealias a = . struct b {
+#^c^#@a
+var d =
diff --git a/validation-test/IDE/crashers/76eec4988cb5a61d.swift b/validation-test/IDE/crashers/76eec4988cb5a61d.swift
new file mode 100644
index 0000000000000..72f156e73c2ca
--- /dev/null
+++ b/validation-test/IDE/crashers/76eec4988cb5a61d.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"1bd67425","signature":"swift::diagnoseMissingOwnership(swift::ParamSpecifier, swift::TypeRepr*, swift::Type, swift::TypeResolution const&)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@a(0#^^#-> b->func > <b
diff --git a/validation-test/IDE/crashers/77896730013ed459.swift b/validation-test/IDE/crashers/77896730013ed459.swift
new file mode 100644
index 0000000000000..e1ff5b77f630e
--- /dev/null
+++ b/validation-test/IDE/crashers/77896730013ed459.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"0b556db7","signature":"diagnoseMatch(swift::ModuleDecl*, swift::NormalProtocolConformance*, swift::ValueDecl*, swift::RequirementMatch const&)","signatureAssert":"Assertion failed: (isa<SubscriptDecl>(Requirement) && \"Unhandled requirement kind\"), function getProtocolRequirementKind"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a {
+  #^^#  macro b
+  struct c: a {
+b
diff --git a/validation-test/IDE/crashers/78f1273d34b9916a.swift b/validation-test/IDE/crashers/78f1273d34b9916a.swift
new file mode 100644
index 0000000000000..63cf32cd78b88
--- /dev/null
+++ b/validation-test/IDE/crashers/78f1273d34b9916a.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","signature":"swift::constraints::ConstraintSystem::addConstraintImpl(swift::constraints::ConstraintKind, swift::Type, swift::Type, swift::constraints::ConstraintLocatorBuilder, bool)","signatureAssert":"Assertion failed: (second && \"Missing second type\"), function addConstraintImpl"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@propertyWrapper struct a {
+wrappedValue: Bool init(wrappedValue: Bool
+var projectedValue init(projectedValue: ) func b(@a ) {
+b#^^#
diff --git a/validation-test/IDE/crashers/796ef3e298a05a47.swift b/validation-test/IDE/crashers/796ef3e298a05a47.swift
new file mode 100644
index 0000000000000..3bdbcad61f11c
--- /dev/null
+++ b/validation-test/IDE/crashers/796ef3e298a05a47.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"5d283fee","signature":"swift::TypeRepr::print(swift::ASTPrinter&, swift::PrintOptions const&, swift::optionset::OptionSet<swift::NonRecursivePrintOption, unsigned int>) const","signatureAssert":"Assertion failed: (ext->canNeverBeBound() && \"Should have been bound by bindExtensions\"), function evaluate"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@abi(
+  extension { #^^#<#declaration#>)
+  <#declaration#>
diff --git a/validation-test/IDE/crashers/7b92bb701b89b249.swift b/validation-test/IDE/crashers/7b92bb701b89b249.swift
new file mode 100644
index 0000000000000..74758bff45ceb
--- /dev/null
+++ b/validation-test/IDE/crashers/7b92bb701b89b249.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"0bdbc8ea","signature":"swift::Parser::parseExprSelector()","signatureAssert":"Assertion failed: (getPtrOrNull() && \"not checked for nullptr\"), function get"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+#selector(a throws  #^^#
diff --git a/validation-test/IDE/crashers/7d168ea6c6715a7c.swift b/validation-test/IDE/crashers/7d168ea6c6715a7c.swift
new file mode 100644
index 0000000000000..d3d2479a7cb38
--- /dev/null
+++ b/validation-test/IDE/crashers/7d168ea6c6715a7c.swift
@@ -0,0 +1,8 @@
+// {"kind":"complete","signature":"swift::GenericSignatureImpl::getSuperclassBound(swift::Type) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a {
+  associatedtype b: Error
+}
+extension a {c
+  #^^#
+  class Error
diff --git a/validation-test/IDE/crashers/7d9bfa9d17f09896.swift b/validation-test/IDE/crashers/7d9bfa9d17f09896.swift
new file mode 100644
index 0000000000000..8add5c20c82ea
--- /dev/null
+++ b/validation-test/IDE/crashers/7d9bfa9d17f09896.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","original":"831da109","signature":"void llvm::function_ref<void (swift::VarDecl*)>::callback_fn<swift::ast_scope::ASTScopeImpl::lookupLocalBindingsInPattern(swift::Pattern const*, swift::namelookup::AbstractASTScopeDeclConsumer&)::$_0>(long, swift::VarDecl*)","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{
+  @abi(func & ()) var a {
+    #^^#
+  }
+}
diff --git a/validation-test/IDE/crashers/81f0b4a8709d344d.swift b/validation-test/IDE/crashers/81f0b4a8709d344d.swift
new file mode 100644
index 0000000000000..389a1d2f60d32
--- /dev/null
+++ b/validation-test/IDE/crashers/81f0b4a8709d344d.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","signature":"bool (anonymous namespace)::StmtChecker::typeCheckStmt<swift::Stmt>(swift::Stmt*&)","signatureAssert":"Assertion failed: (size() >= N && \"Dropping more elements than exist\"), function drop_front"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+let:{ let a=
+#^COMPLETE^#{
+b:{
diff --git a/validation-test/IDE/crashers/825c80698a299f80.swift b/validation-test/IDE/crashers/825c80698a299f80.swift
new file mode 100644
index 0000000000000..b137bcd0d303b
--- /dev/null
+++ b/validation-test/IDE/crashers/825c80698a299f80.swift
@@ -0,0 +1,10 @@
+// {"kind":"complete","original":"081c2cc3","signature":"abortWithVerificationError"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a {
+  associatedtype b: SignedInteger
+    c,
+    : {
+    }
+}
+extension a {
+  d: SignedInteger, #^^#
diff --git a/validation-test/IDE/crashers/8447838e00019fde.swift b/validation-test/IDE/crashers/8447838e00019fde.swift
new file mode 100644
index 0000000000000..7fe99434dbe74
--- /dev/null
+++ b/validation-test/IDE/crashers/8447838e00019fde.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::ParserStatus llvm::function_ref<swift::ParserStatus ()>::callback_fn<swift::Parser::parseParameterClause(swift::SourceLoc&, llvm::SmallVectorImpl<swift::Parser::ParsedParameter>&, swift::SourceLoc&, swift::Parser::DefaultArgumentInfo*, swift::Parser::ParameterContextKind)::$_0>(long)","signatureAssert":"Assertion failed: (getPtrOrNull() && \"not checked for nullptr\"), function get"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func 丏(=1 as
+#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/8659dc98be5856f6.swift b/validation-test/IDE/crashers/8659dc98be5856f6.swift
new file mode 100644
index 0000000000000..e2a6779d63917
--- /dev/null
+++ b/validation-test/IDE/crashers/8659dc98be5856f6.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"bool (anonymous namespace)::StmtChecker::typeCheckStmt<swift::Stmt>(swift::Stmt*&)"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension {
+a { discard b#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/8668a3eb11f2ba0f.swift b/validation-test/IDE/crashers/8668a3eb11f2ba0f.swift
new file mode 100644
index 0000000000000..5070db395f35b
--- /dev/null
+++ b/validation-test/IDE/crashers/8668a3eb11f2ba0f.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::ide::USRBasedType::fromType(swift::Type, swift::ide::USRBasedTypeArena&)","stackOverflow":true}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a: c {  b(a  = #^^# }
+protocol c: a
diff --git a/validation-test/IDE/crashers/8681205caefae96e.swift b/validation-test/IDE/crashers/8681205caefae96e.swift
new file mode 100644
index 0000000000000..2eb93b6106e28
--- /dev/null
+++ b/validation-test/IDE/crashers/8681205caefae96e.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::ide::CompletionLookup::getValueExprCompletions(swift::Type, swift::ValueDecl*, bool)","signatureAssert":"Assertion failed: (IsUnwrappedOptional && \"IUOs should be optional if not bound/forced\"), function tryUnwrappedCompletions"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func a(b: (() -> Float)!) {
+b()#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/87443a182257da1e.swift b/validation-test/IDE/crashers/87443a182257da1e.swift
new file mode 100644
index 0000000000000..6bc1c60b9935b
--- /dev/null
+++ b/validation-test/IDE/crashers/87443a182257da1e.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"bf3927a1","signature":"swift::TypeChecker::resolveDeclRefExpr(swift::UnresolvedDeclRefExpr*, swift::DeclContext*)","signatureAssert":"Assertion failed: (isValid() && \"Can't advance an invalid location\"), function getAdvancedLoc"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+postfix operator %%
+postfix func % (a)
+func b c b #^^#
diff --git a/validation-test/IDE/crashers/88724bf42982b346.swift b/validation-test/IDE/crashers/88724bf42982b346.swift
new file mode 100644
index 0000000000000..22d32ae69c759
--- /dev/null
+++ b/validation-test/IDE/crashers/88724bf42982b346.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::TypeBase::getContextSubstitutions(swift::DeclContext const*, swift::GenericEnvironment*)","signatureAssert":"Assertion failed: (!baseTy->is<LValueType>() && !baseTy->is<AnyMetatypeType>() && !baseTy->is<ErrorType>()), function getContextSubstitutions"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a extension a where Self == { extension a#^COMPLETE^# protocol b
diff --git a/validation-test/IDE/crashers/88987db0d0dc470c.swift b/validation-test/IDE/crashers/88987db0d0dc470c.swift
new file mode 100644
index 0000000000000..e97e9f3c9ad80
--- /dev/null
+++ b/validation-test/IDE/crashers/88987db0d0dc470c.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"092969d1","signature":"swift::ide::IDEInspectionInstance::performCachedOperationIfPossible(llvm::hash_code, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, swift::SearchPathOptions const&, llvm::MemoryBuffer*, unsigned int, swift::DiagnosticConsumer*, std::__1::shared_ptr<std::__1::atomic<bool>>, llvm::function_ref<void (swift::ide::CancellableResult<swift::ide::IDEInspectionInstanceResult>)>)","signatureAssert":"Assertion failed: (reparsedInfo.Kind == newInfo.Kind), function performCachedOperationIfPossible","useSourceOrderCompletion":true}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-order-completion -source-filename %s
+#^^# @
+#^a^# b
diff --git a/validation-test/IDE/crashers/8b1e4c7f2174671c.swift b/validation-test/IDE/crashers/8b1e4c7f2174671c.swift
new file mode 100644
index 0000000000000..a8ac615a5ddbe
--- /dev/null
+++ b/validation-test/IDE/crashers/8b1e4c7f2174671c.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"2201e4ed","signature":"swift::Mangle::ASTMangler::mangleDeclAsUSR(swift::ValueDecl const*, llvm::StringRef)"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+enum a<b{ protocol c{ class d{ class f<b let e=f #^^#
diff --git a/validation-test/IDE/crashers/93646f990f2e8498.swift b/validation-test/IDE/crashers/93646f990f2e8498.swift
new file mode 100644
index 0000000000000..052a50f670261
--- /dev/null
+++ b/validation-test/IDE/crashers/93646f990f2e8498.swift
@@ -0,0 +1,11 @@
+// {"kind":"complete","original":"ac690622","signature":"swift::rewriting::RequirementMachine::requiresClass(swift::Type) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a {
+associatedtype b
+func c -> b
+struct d<e: Collection, f
+>: a
+where e.Element ==
+{
+c -> some a {
+self#^^#
diff --git a/validation-test/IDE/crashers/96faa1ddef0cb57f.swift b/validation-test/IDE/crashers/96faa1ddef0cb57f.swift
new file mode 100644
index 0000000000000..c8cd23b13c991
--- /dev/null
+++ b/validation-test/IDE/crashers/96faa1ddef0cb57f.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"openTypeParameter(swift::constraints::ConstraintSystem&, swift::Type, swift::GenericEnvironment*, llvm::DenseMap<swift::SubstitutableType*, swift::TypeVariableType*, llvm::DenseMapInfo<swift::SubstitutableType*, void>, llvm::detail::DenseMapPair<swift::SubstitutableType*, swift::TypeVariableType*>>&)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a<b:RangeReplaceableCollection where b ={ c: b.Element? { #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/974abc9e171ad368.swift b/validation-test/IDE/crashers/974abc9e171ad368.swift
new file mode 100644
index 0000000000000..27eec93a624ef
--- /dev/null
+++ b/validation-test/IDE/crashers/974abc9e171ad368.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"e6459edc","signature":"swift::TypeChecker::typeCheckStmtConditionElement(swift::StmtConditionElement&, bool&, swift::DeclContext*)","signatureAssert":"Assertion failed: (!E->getType() && \"the bool condition is already type checked\"), function typeCheckBooleanStmtConditionElement"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+(if) {}#^^#
diff --git a/validation-test/IDE/crashers/9949f94be543b413.swift b/validation-test/IDE/crashers/9949f94be543b413.swift
new file mode 100644
index 0000000000000..c96d57f94ae6a
--- /dev/null
+++ b/validation-test/IDE/crashers/9949f94be543b413.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","signature":"swift::ConformanceLookupTable::compareConformances(swift::ConformanceLookupTable::ConformanceEntry*, swift::ConformanceLookupTable::ConformanceEntry*, bool&)","signatureAssert":"Assertion failed: (lhs->getDeclContext()->getParentModule() == rhs->getDeclContext()->getParentModule() && \"conformances should be in the same module\"), function compareConformances","useSourceOrderCompletion":true}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-order-completion -source-filename %s
+class a {
+  #^^#
+}
+extension a? : RandomAccessCollection {
+  #^b^#
diff --git a/validation-test/IDE/crashers/99e962b241f1d25b.swift b/validation-test/IDE/crashers/99e962b241f1d25b.swift
new file mode 100644
index 0000000000000..5ba3fa642823e
--- /dev/null
+++ b/validation-test/IDE/crashers/99e962b241f1d25b.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"10b7f522","signature":"swift::TypeRepr::print(swift::ASTPrinter&, swift::PrintOptions const&, swift::optionset::OptionSet<swift::NonRecursivePrintOption, unsigned int>) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+if{ extension{ a{ #^^##^b^#
diff --git a/validation-test/IDE/crashers/9f45d664f93ae6f7.swift b/validation-test/IDE/crashers/9f45d664f93ae6f7.swift
new file mode 100644
index 0000000000000..409db4206871f
--- /dev/null
+++ b/validation-test/IDE/crashers/9f45d664f93ae6f7.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"588b7eea","signature":"swift::BoundGenericType::get(swift::NominalTypeDecl*, swift::Type, llvm::ArrayRef<swift::Type>)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+// REQUIRES: OS=macosx
+import Foundation
+Foundation[
+  #^^#]
diff --git a/validation-test/IDE/crashers/9fefcf40293db48f.swift b/validation-test/IDE/crashers/9fefcf40293db48f.swift
new file mode 100644
index 0000000000000..37f9c3ae66541
--- /dev/null
+++ b/validation-test/IDE/crashers/9fefcf40293db48f.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"2ab8a74a","signature":"swift::TypeDecl::getName() const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension {
+  subscript -> a {
+    @
+    #^^#
diff --git a/validation-test/IDE/crashers/a41cd43f2f603f31.swift b/validation-test/IDE/crashers/a41cd43f2f603f31.swift
new file mode 100644
index 0000000000000..d6ff6970e116d
--- /dev/null
+++ b/validation-test/IDE/crashers/a41cd43f2f603f31.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::Parser::parseDecl(bool, bool, llvm::function_ref<void (swift::Decl*)>, bool)","signatureAssert":"Assertion failed: (!InEnumElementRawValue), function completeNominalMemberBeginning"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+case <#expression#>= { protocol a { #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/a51bc03e2023ede5.swift b/validation-test/IDE/crashers/a51bc03e2023ede5.swift
new file mode 100644
index 0000000000000..9e77f6fead89d
--- /dev/null
+++ b/validation-test/IDE/crashers/a51bc03e2023ede5.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::constraints::ConstraintSystem::buildDisjunctionForOptionalVsUnderlying(swift::Type, swift::Type, swift::constraints::ConstraintLocator*)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a {b: c! = b #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/ab3972c8c6c1b5d6.swift b/validation-test/IDE/crashers/ab3972c8c6c1b5d6.swift
new file mode 100644
index 0000000000000..a835ccd251123
--- /dev/null
+++ b/validation-test/IDE/crashers/ab3972c8c6c1b5d6.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"5070984e","signature":"swift::Decl::getResolvedCustomAttrType(swift::CustomAttr*) const","signatureAssert":"Assertion failed: ((range.isValid()) && \"scope has invalid source range\"), function getCharSourceRangeOfScope"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@a var b {
+  @#^^#< #declaration
+  #>
+}
diff --git a/validation-test/IDE/crashers/acb0013ae9149246.swift b/validation-test/IDE/crashers/acb0013ae9149246.swift
new file mode 100644
index 0000000000000..28783d8199988
--- /dev/null
+++ b/validation-test/IDE/crashers/acb0013ae9149246.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","signature":"swift::DeclContext::getASTContext() const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@ a(
+#^COMPLETE^# {}
+let b
diff --git a/validation-test/IDE/crashers/ae7830cc768ad130.swift b/validation-test/IDE/crashers/ae7830cc768ad130.swift
new file mode 100644
index 0000000000000..5859728896be5
--- /dev/null
+++ b/validation-test/IDE/crashers/ae7830cc768ad130.swift
@@ -0,0 +1,8 @@
+// {"kind":"complete","original":"0715e0e8","signature":"swift::Decl::getSemanticAvailableAttr(swift::AvailableAttr const*) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a {
+  @available(*, renamed: "request0")
+  !
+  b ,() {}
+}
+#^^#
diff --git a/validation-test/IDE/crashers/b702ab48c2f29a3a.swift b/validation-test/IDE/crashers/b702ab48c2f29a3a.swift
new file mode 100644
index 0000000000000..239d851fae9e5
--- /dev/null
+++ b/validation-test/IDE/crashers/b702ab48c2f29a3a.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::rewriting::RequirementMachine::lookupNestedType(swift::Type, swift::Identifier) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a<b{ c { struct d<f where f.e#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/b74734c97bb09b60.swift b/validation-test/IDE/crashers/b74734c97bb09b60.swift
new file mode 100644
index 0000000000000..35af03df2c8ec
--- /dev/null
+++ b/validation-test/IDE/crashers/b74734c97bb09b60.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"0cd48ae7","signature":"swift::TypeBase::getReducedShape()","signatureAssert":"Assertion failed: (!isTypeVariableOrMember()), function getReducedShape"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a<each b { c: (repeat each b )! { c #^^#
diff --git a/validation-test/IDE/crashers/b94c7eab64f2421b.swift b/validation-test/IDE/crashers/b94c7eab64f2421b.swift
new file mode 100644
index 0000000000000..27acc2613c23e
--- /dev/null
+++ b/validation-test/IDE/crashers/b94c7eab64f2421b.swift
@@ -0,0 +1,10 @@
+// {"kind":"complete","original":"66e1ef62","signature":"swift::Mangle::ASTMangler::appendConstrainedExistential(swift::Type, swift::GenericSignature, swift::ValueDecl const*)","stackOverflow":true}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a<b, c> {
+  associatedtype b
+  associatedtype c
+}
+var b {
+  #^^#
+}
+func d() -> a<a, some a>
diff --git a/validation-test/IDE/crashers/bc178c6fbc3ad18e.swift b/validation-test/IDE/crashers/bc178c6fbc3ad18e.swift
new file mode 100644
index 0000000000000..42099602b1ddd
--- /dev/null
+++ b/validation-test/IDE/crashers/bc178c6fbc3ad18e.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"3946e52f","signature":"(anonymous namespace)::AssociatedTypeInference::inferTypeWitnessesViaValueWitnesses(llvm::SetVector<swift::AssociatedTypeDecl*, llvm::SmallVector<swift::AssociatedTypeDecl*, 0u>, llvm::DenseSet<swift::AssociatedTypeDecl*, llvm::DenseMapInfo<swift::AssociatedTypeDecl*, void>>, 0u> const&)","signatureAssert":"Assertion failed: (false && \"Should be exhaustive\"), function checkForPotentialCycle"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a : RandomAccessCollection { class endIndex { b -> Element #^^#
diff --git a/validation-test/IDE/crashers/be524c3ba9746301.swift b/validation-test/IDE/crashers/be524c3ba9746301.swift
new file mode 100644
index 0000000000000..caec57e90583d
--- /dev/null
+++ b/validation-test/IDE/crashers/be524c3ba9746301.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"1433c7e3","signature":"swift::ide::KeyPathTypeCheckCompletionCallback::sawSolutionImpl(swift::constraints::Solution const&)","signatureAssert":"Assertion failed: (ComponentIndex < KeyPath->getComponents().size() && \"Didn't find a code compleiton component?\"), function sawSolutionImpl"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{ \a#^^# ? }
+<
diff --git a/validation-test/IDE/crashers/bf2a1e697e134b1b.swift b/validation-test/IDE/crashers/bf2a1e697e134b1b.swift
new file mode 100644
index 0000000000000..c1090b3a87814
--- /dev/null
+++ b/validation-test/IDE/crashers/bf2a1e697e134b1b.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::MacroDefinitionRequest::evaluate(swift::Evaluator&, swift::MacroDecl*) const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+macro a = ( @freestanding macro b = a#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/c9107b491555f468.swift b/validation-test/IDE/crashers/c9107b491555f468.swift
new file mode 100644
index 0000000000000..99cc16d1de15a
--- /dev/null
+++ b/validation-test/IDE/crashers/c9107b491555f468.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"parseGuardedPattern(swift::Parser&, (anonymous namespace)::GuardedPattern&, swift::ParserStatus&, llvm::SmallVectorImpl<swift::VarDecl*>&, (anonymous namespace)::GuardedPatternContext, bool)","signatureAssert":"Assertion failed: (!InEnumElementRawValue), function completeCaseStmtBeginning"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+case = switch { case #^COMPLETE^#<#expression#>
diff --git a/validation-test/IDE/crashers/cdc75ec659bc26a6.swift b/validation-test/IDE/crashers/cdc75ec659bc26a6.swift
new file mode 100644
index 0000000000000..b40c059dbb413
--- /dev/null
+++ b/validation-test/IDE/crashers/cdc75ec659bc26a6.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"a4349038","signature":"(anonymous namespace)::TypeResolver::resolveTupleType(swift::TupleTypeRepr*, swift::TypeResolutionOptions)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func a<b > -> () [ {
+  var : (b) #^^#
diff --git a/validation-test/IDE/crashers/cfad4ec3ad706bac.swift b/validation-test/IDE/crashers/cfad4ec3ad706bac.swift
new file mode 100644
index 0000000000000..0f8403b6978bd
--- /dev/null
+++ b/validation-test/IDE/crashers/cfad4ec3ad706bac.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"b353d673","signature":"swift::ide::ArgumentTypeCheckCompletionCallback::sawSolutionImpl(swift::constraints::Solution const&)","signatureAssert":"Assertion failed: (false && \"bad parent call match?\"), function sawSolutionImpl"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{
+  b ? \.a  (#^^#
+}(
diff --git a/validation-test/IDE/crashers/d02ac29b7ce07e7d.swift b/validation-test/IDE/crashers/d02ac29b7ce07e7d.swift
new file mode 100644
index 0000000000000..ae26b3cf0a969
--- /dev/null
+++ b/validation-test/IDE/crashers/d02ac29b7ce07e7d.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::ide::getTypeForCompletion(swift::constraints::Solution const&, swift::ASTNode)","signatureAssert":"Assertion failed: (false && \"Expression wasn't type checked?\"), function getTypeForCompletion"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+#fileLiteral(#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/d3a218e40a4e3b8e.swift b/validation-test/IDE/crashers/d3a218e40a4e3b8e.swift
new file mode 100644
index 0000000000000..64a430518e320
--- /dev/null
+++ b/validation-test/IDE/crashers/d3a218e40a4e3b8e.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::Parser::performIDEInspectionSecondPassImpl(swift::IDEInspectionDelayedDeclState&)","signatureAssert":"Assertion failed: ((DC->isTypeContext() || DC->isModuleScopeContext()) && \"Delayed decl must be a type member or a top-level decl\"), function performIDEInspectionSecondPassImpl"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+defer{ var #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/d41add6f5844fe32.swift b/validation-test/IDE/crashers/d41add6f5844fe32.swift
new file mode 100644
index 0000000000000..9612c4fb90934
--- /dev/null
+++ b/validation-test/IDE/crashers/d41add6f5844fe32.swift
@@ -0,0 +1,13 @@
+// {"kind":"complete","signature":"swift::Mangle::ASTMangler::appendExtension(swift::ExtensionDecl const*, swift::Mangle::ASTMangler::BaseEntitySignature&, llvm::StringRef)","stackOverflow":true}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+public struct Wrapper<T: P> {}
+extension Wrapper: Q where T: Q {
+  public protocol PBase {
+    associatedtype AssocType
+  }
+  public protocol P: PBase {
+    override associatedtype AssocType:#^^# P = Wrapper<Self>
+  }
+  public protocol Q: P where SelfAssocType: Q {}
+  public protocol R: Q where Self.AssocType: R {}
+}
diff --git a/validation-test/IDE/crashers/d500691bf5d28bbc.swift b/validation-test/IDE/crashers/d500691bf5d28bbc.swift
new file mode 100644
index 0000000000000..c53dbb0f1da61
--- /dev/null
+++ b/validation-test/IDE/crashers/d500691bf5d28bbc.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","original":"44c76fac","signature":"bool (anonymous namespace)::StmtChecker::typeCheckStmt<swift::Stmt>(swift::Stmt*&)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a where b == <#type#>[ {
+  func c() -> Self {
+    #^^#
+  }
+}
diff --git a/validation-test/IDE/crashers/d7b68d01c9ccf2f4.swift b/validation-test/IDE/crashers/d7b68d01c9ccf2f4.swift
new file mode 100644
index 0000000000000..21e3e1944c008
--- /dev/null
+++ b/validation-test/IDE/crashers/d7b68d01c9ccf2f4.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","signature":"swift::Mangle::Mangler::verify(llvm::StringRef, swift::Mangle::ManglingFlavor)"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a {
+  fileprivate associatedtype b
+  func c ->
+  #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/dac2016ff43c557e.swift b/validation-test/IDE/crashers/dac2016ff43c557e.swift
new file mode 100644
index 0000000000000..d19324c8223e0
--- /dev/null
+++ b/validation-test/IDE/crashers/dac2016ff43c557e.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::FragileFunctionKindRequest::OutputType swift::Evaluator::getResultUncached<swift::FragileFunctionKindRequest, swift::FragileFunctionKindRequest::OutputType swift::evaluateOrDefault<swift::FragileFunctionKindRequest>(swift::Evaluator&, swift::FragileFunctionKindRequest, swift::FragileFunctionKindRequest::OutputType)::'lambda'()>(swift::FragileFunctionKindRequest const&, swift::FragileFunctionKindRequest::OutputType swift::evaluateOrDefault<swift::FragileFunctionKindRequest>(swift::Evaluator&, swift::FragileFunctionKindRequest, swift::FragileFunctionKindRequest::OutputType)::'lambda'())","signatureAssert":"Assertion failed: (Val && \"isa<> used on a null pointer\"), function doit"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+case ( <#expression#>= { enum a : #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/dffa2c2577e3e101.swift b/validation-test/IDE/crashers/dffa2c2577e3e101.swift
new file mode 100644
index 0000000000000..39bec6441535a
--- /dev/null
+++ b/validation-test/IDE/crashers/dffa2c2577e3e101.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"7f4bcc9e","signature":"swift::DeclContext::getDeclaredInterfaceType() const","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension Sequence where a == b[ {
+  func c() -> #^^#
+}
diff --git a/validation-test/IDE/crashers/e52359b2767fa879.swift b/validation-test/IDE/crashers/e52359b2767fa879.swift
new file mode 100644
index 0000000000000..c050f9ae5964d
--- /dev/null
+++ b/validation-test/IDE/crashers/e52359b2767fa879.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","original":"108dc1e5","signature":"swift::TypeDecl::getName() const","signatureAssert":"Assertion failed: (Index < Length && \"Invalid index!\"), function operator[]"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension {
+a {
+  typealias b = ()?
+  let c = b?? ()
+  #^^#
diff --git a/validation-test/IDE/crashers/e8698acd627edf0b.swift b/validation-test/IDE/crashers/e8698acd627edf0b.swift
new file mode 100644
index 0000000000000..06b8998c8febe
--- /dev/null
+++ b/validation-test/IDE/crashers/e8698acd627edf0b.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"bae855bf","signature":"swift::GenericTypeParamDecl::getSourceRange() const","signatureAssert":"Assertion failed: (Start.isValid() == End.isValid() && \"Start and end should either both be valid or both be invalid!\"), function SourceRange"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a<b: c, b extension a where b #^^#
diff --git a/validation-test/IDE/crashers/ead1bd1fccd220ab.swift b/validation-test/IDE/crashers/ead1bd1fccd220ab.swift
new file mode 100644
index 0000000000000..9aafcebdf891f
--- /dev/null
+++ b/validation-test/IDE/crashers/ead1bd1fccd220ab.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"57e49e10","signature":"finishStorageImplInfo(swift::AbstractStorageDecl*, swift::StorageImplInfo&)"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a {
+lazy(b, c) { b#^^#
diff --git a/validation-test/IDE/crashers/eaf1c77e3b7e20c6.swift b/validation-test/IDE/crashers/eaf1c77e3b7e20c6.swift
new file mode 100644
index 0000000000000..6f635e25323a4
--- /dev/null
+++ b/validation-test/IDE/crashers/eaf1c77e3b7e20c6.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"2aa5adcf","signature":"swift::GenericContext::getGenericSignature() const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a<b> : Collection }
+a.Iterator.c #^^#
diff --git a/validation-test/IDE/crashers/f03bb3278d3341d9.swift b/validation-test/IDE/crashers/f03bb3278d3341d9.swift
new file mode 100644
index 0000000000000..d5aaed1496f5d
--- /dev/null
+++ b/validation-test/IDE/crashers/f03bb3278d3341d9.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","signature":"swift::Parser::consumeTopLevelDecl(swift::ParserPosition, swift::TopLevelCodeDecl*)","signatureAssert":"Assertion failed: (!IDEInspectionDelayedDeclStat.get() && \"only one decl can be delayed for code completion\"), function setIDEInspectionDelayedDeclState"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+guard {
+#if #^COMPLETE^#
+0
diff --git a/validation-test/IDE/crashers/f13530ddd8d62d26.swift b/validation-test/IDE/crashers/f13530ddd8d62d26.swift
new file mode 100644
index 0000000000000..abc983d593b02
--- /dev/null
+++ b/validation-test/IDE/crashers/f13530ddd8d62d26.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","signature":"swift::NominalTypeDecl::prepareConformanceTable() const","signatureAssert":"Assertion failed: (!isa<ProtocolDecl>(this) && \"Protocols don't have a conformance table\"), function prepareConformanceTable"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a< b {
+  associatedtype b
+  func c<d>: a<d>#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/f75dad9059dcd5e4.swift b/validation-test/IDE/crashers/f75dad9059dcd5e4.swift
new file mode 100644
index 0000000000000..c208c76d5c586
--- /dev/null
+++ b/validation-test/IDE/crashers/f75dad9059dcd5e4.swift
@@ -0,0 +1,9 @@
+// {"kind":"complete","signature":"swift::GenericSignatureImpl::requiresProtocol(swift::Type, swift::ProtocolDecl*) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a {
+  associatedtype b
+}
+protocol c : a where c== d
+  extension c {
+    typealias c = b
+    #^^#
diff --git a/validation-test/IDE/crashers/f98762f9df9ed0fa.swift b/validation-test/IDE/crashers/f98762f9df9ed0fa.swift
new file mode 100644
index 0000000000000..629db0f072696
--- /dev/null
+++ b/validation-test/IDE/crashers/f98762f9df9ed0fa.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","signature":"swift::rewriting::RewriteContext::getMutableTermForType(swift::CanType, swift::ProtocolDecl const*)","signatureAssert":"Assertion failed: (paramType->isTypeParameter()), function getMutableTermForType"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+protocol a { associatedtype b }
+protocol c { associatedtype b }
+extension c { compose<d where d ==a, d.b == b { #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/fa71279755a2cb53.swift b/validation-test/IDE/crashers/fa71279755a2cb53.swift
new file mode 100644
index 0000000000000..5efa8ff6c817c
--- /dev/null
+++ b/validation-test/IDE/crashers/fa71279755a2cb53.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::GenericSignatureImpl::requiresClass(swift::Type) const"}
+// RUN: not --crash %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -code-completion-diagnostics -source-filename %s
+protocol a { associatedtype c: a var b: c }
+protocol d: a where c == Never extension Never: d extension d { b: Never { #^COMPLETE^#
diff --git a/validation-test/IDE/crashers/fc02f5bc68d44605.swift b/validation-test/IDE/crashers/fc02f5bc68d44605.swift
new file mode 100644
index 0000000000000..7fde45b1b2090
--- /dev/null
+++ b/validation-test/IDE/crashers/fc02f5bc68d44605.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"90f5eddd","signature":"$s11swiftASTGen19emitDiagnosticParts33_5015A222471F7FD97A302015E08809A0LL16diagnosticEngine16sourceFileBuffer7message8severity8position6offset10highlights5editsySo07BridgeddM0V_SRys5UInt8VGSS25_CompilerSwiftDiagnostics0D8SeverityO01_yZ6Syntax16AbsolutePositionVSiSayAT6SyntaxVGSayAT10SourceEditVGtFSo0wD0VSo0W9StringRefVXEfU_","useSourceOrderCompletion":true}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-order-completion -source-filename %s
+// REQUIRES: swift_swift_parser
+extension a { b {
+#^^#macro c =
+#^d^#
diff --git a/validation-test/IDE/crashers/fd1bd523c6eba84d.swift b/validation-test/IDE/crashers/fd1bd523c6eba84d.swift
new file mode 100644
index 0000000000000..2b02644a5b02a
--- /dev/null
+++ b/validation-test/IDE/crashers/fd1bd523c6eba84d.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","signature":"swift::Parser::parseLineDirective(bool)","signatureAssert":"Assertion failed: (isNewFile), function parseLineDirective"}
+// RUN: not --crash %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{
+#sourceLocation(file: "", line: 800)
+#^COMPLETE^#
diff --git a/validation-test/IDE/crashers/lit.local.cfg b/validation-test/IDE/crashers/lit.local.cfg
new file mode 100644
index 0000000000000..0f7012126c4f3
--- /dev/null
+++ b/validation-test/IDE/crashers/lit.local.cfg
@@ -0,0 +1,2 @@
+if "asserts" not in config.available_features:
+    config.unsupported = True
diff --git a/validation-test/IDE/crashers_2_fixed/pr-82147.swift b/validation-test/IDE/crashers_2_fixed/pr-82147.swift
new file mode 100644
index 0000000000000..4076b7688c5a9
--- /dev/null
+++ b/validation-test/IDE/crashers_2_fixed/pr-82147.swift
@@ -0,0 +1,20 @@
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=COMPLETE -source-filename=%s
+
+// https://github.com/swiftlang/swift/pull/82147
+
+protocol P {
+  associatedtype X
+}
+
+struct S<T> {
+  init<U, V>() where T == (U, V) {}
+}
+extension S : P where T : P {
+  typealias X = T.X
+}
+
+func foo<T: P, U>(_: () -> T) where U == T.X {}
+
+foo {
+  S(#^COMPLETE^#)
+}
diff --git a/validation-test/IDE/crashers_fixed/003-swift-typebase-getcanonicaltype.swift b/validation-test/IDE/crashers_fixed/003-swift-typebase-getcanonicaltype.swift
index 081aca3826f85..3cb2a8f85892e 100644
--- a/validation-test/IDE/crashers_fixed/003-swift-typebase-getcanonicaltype.swift
+++ b/validation-test/IDE/crashers_fixed/003-swift-typebase-getcanonicaltype.swift
@@ -1,2 +1,5 @@
-// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// We disable USR to Decl verification since the USR for declarations within the
+// extension with no type name have a USR that looks like a top-level declaration.
+
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s -code-completion-verify-usr-to-decl=false
 extension{struct E{enum C{let a{#^A^#
diff --git a/validation-test/IDE/crashers_fixed/006-swift-declcontext-getprotocolself.swift b/validation-test/IDE/crashers_fixed/006-swift-declcontext-getprotocolself.swift
index 921064a856277..91fdde27dea99 100644
--- a/validation-test/IDE/crashers_fixed/006-swift-declcontext-getprotocolself.swift
+++ b/validation-test/IDE/crashers_fixed/006-swift-declcontext-getprotocolself.swift
@@ -1,3 +1,6 @@
-// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// We disable USR to Decl verification since the USR for declarations within the
+// extension with no type name have a USR that looks like a top-level declaration.
+
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s -code-completion-verify-usr-to-decl=false
 extension{protocol a{func p)struct A{protocol c
 let a{#^A^#
diff --git a/validation-test/IDE/crashers_fixed/036-swift-constraints-constraintsystem-matchdeepequalitytypes.swift b/validation-test/IDE/crashers_fixed/036-swift-constraints-constraintsystem-matchdeepequalitytypes.swift
index 920b5b3b1d6e1..69ce66f00512f 100644
--- a/validation-test/IDE/crashers_fixed/036-swift-constraints-constraintsystem-matchdeepequalitytypes.swift
+++ b/validation-test/IDE/crashers_fixed/036-swift-constraints-constraintsystem-matchdeepequalitytypes.swift
@@ -1,3 +1,3 @@
-// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s -code-completion-verify-usr-to-decl=false
 extension{enum B{enum B{enum S{func c
 let t=c{#^A^#
diff --git a/validation-test/IDE/crashers_fixed/064-swift-genericfunctiontype-get.swift b/validation-test/IDE/crashers_fixed/064-swift-genericfunctiontype-get.swift
index d51c49171897a..6ec6db919e5c6 100644
--- a/validation-test/IDE/crashers_fixed/064-swift-genericfunctiontype-get.swift
+++ b/validation-test/IDE/crashers_fixed/064-swift-genericfunctiontype-get.swift
@@ -1,3 +1,6 @@
-// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// We disable USR to Decl verification since the USR for declarations within the
+// extension with no type name have a USR that looks like a top-level declaration.
+
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s -code-completion-verify-usr-to-decl=false
 extension{enum a<H{enum b{case
 func a(=#^A^#
diff --git a/validation-test/IDE/crashers_fixed/08fb80df278d76cd.swift b/validation-test/IDE/crashers_fixed/08fb80df278d76cd.swift
new file mode 100644
index 0000000000000..20db925a8258a
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/08fb80df278d76cd.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"098f0ede","signature":"swift::constraints::ConstraintSystem::getMemberReferenceTypeFromOpenedType(swift::Type, swift::Type, swift::ValueDecl*, swift::constraints::ConstraintLocator*, bool, bool)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+enum a<b> {
+  c=d#^^#  macro d()
+}
diff --git a/validation-test/IDE/crashers_fixed/1118c1956154924d.swift b/validation-test/IDE/crashers_fixed/1118c1956154924d.swift
new file mode 100644
index 0000000000000..6309785a07117
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/1118c1956154924d.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::constraints::ConstraintSystem::assignFixedType(swift::TypeVariableType*, swift::Type, bool, bool)","signatureAssert":"Assertion failed: (!type->hasError() && \"Should not be assigning a type involving ErrorType!\"), function assignFixedType"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+[ _""#^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/14fef9539c874eb2.swift b/validation-test/IDE/crashers_fixed/14fef9539c874eb2.swift
new file mode 100644
index 0000000000000..df037d89be6f9
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/14fef9539c874eb2.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"void std::__1::__introsort<std::__1::_ClassicAlgPolicy, printCodeCompletionLookedupTypeNames(llvm::ArrayRef<swift::NullTerminatedStringRef>, llvm::raw_ostream&)::$_0&, swift::NullTerminatedStringRef*, false>(swift::NullTerminatedStringRef*, swift::NullTerminatedStringRef*, printCodeCompletionLookedupTypeNames(llvm::ArrayRef<swift::NullTerminatedStringRef>, llvm::raw_ostream&)::$_0&, std::__1::iterator_traits<swift::NullTerminatedStringRef*>::difference_type, bool)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{
+$1 == [$1 ]#^^#
diff --git a/validation-test/IDE/crashers_fixed/15d1c6f76ad86540.swift b/validation-test/IDE/crashers_fixed/15d1c6f76ad86540.swift
new file mode 100644
index 0000000000000..e51ce075c29dc
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/15d1c6f76ad86540.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","signature":"swift::GenericSignatureImpl::getReducedType(swift::Type) const"}
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -source-filename %s
+protocol a: Collection where Iterator == b<Self> {
+  struct b<c: a>: IteratorProtocol
+    func d ->
+    #^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/2310a05b9a395ec4.swift b/validation-test/IDE/crashers_fixed/2310a05b9a395ec4.swift
new file mode 100644
index 0000000000000..97e330dabc096
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/2310a05b9a395ec4.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::ide::AfterPoundExprCompletion::sawSolutionImpl(swift::constraints::Solution const&)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{##^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/23da5344b07b939.swift b/validation-test/IDE/crashers_fixed/23da5344b07b939.swift
new file mode 100644
index 0000000000000..3d0980e8f785d
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/23da5344b07b939.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::AnyFunctionType::getExtInfo() const","signatureAssert":"Assertion failed: (hasExtInfo()), function getExtInfo"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func a(b) a#^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/2681cf587abeb72.swift b/validation-test/IDE/crashers_fixed/2681cf587abeb72.swift
new file mode 100644
index 0000000000000..81c6268949efa
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/2681cf587abeb72.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"2ad6764c","signature":"swift::constraints::Solution::getType(swift::KeyPathExpr const*, unsigned int) const","signatureAssert":"Assertion failed: (hasType(KP, I) && \"Expected type to have been set!\"), function getType"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+0 -> \ a#^^#
+!
diff --git a/validation-test/IDE/crashers_fixed/2a9258ff5360857f.swift b/validation-test/IDE/crashers_fixed/2a9258ff5360857f.swift
new file mode 100644
index 0000000000000..4437c5b9745c2
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/2a9258ff5360857f.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"19b878fc","signature":"swift::NamingPatternRequest::evaluate(swift::Evaluator&, swift::VarDecl*) const","signatureAssert":"Assertion failed: (foundVarDecl && \"VarDecl not declared in its parent?\"), function evaluate"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{
+  guard let \a = answer
+    a
+    #^^#
diff --git a/validation-test/IDE/crashers_fixed/32b0b9ccc582da78.swift b/validation-test/IDE/crashers_fixed/32b0b9ccc582da78.swift
new file mode 100644
index 0000000000000..30ecc719d4692
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/32b0b9ccc582da78.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"f8c1c082","signature":"swift::ide::PostfixCompletionCallback::Result::tryMerge(swift::ide::PostfixCompletionCallback::Result const&, swift::DeclContext*)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+typealias a = () arr = [a].append([
+0])#^^#
diff --git a/validation-test/IDE/crashers_fixed/38a36bbe0fc496da.swift b/validation-test/IDE/crashers_fixed/38a36bbe0fc496da.swift
new file mode 100644
index 0000000000000..71248dbbe607b
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/38a36bbe0fc496da.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","original":"61e9155a","signature":"swift::ide::CodeCompletionResultBuilder::takeResult()"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension ()
+where
+  #^^# == <#type#>
+{
+}
diff --git a/validation-test/IDE/crashers_fixed/3ef1bab1e79a83a5.swift b/validation-test/IDE/crashers_fixed/3ef1bab1e79a83a5.swift
new file mode 100644
index 0000000000000..bc1b067c66d56
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/3ef1bab1e79a83a5.swift
@@ -0,0 +1,8 @@
+// {"kind":"complete","original":"018f6774","signature":"swift::TypeChecker::typeCheckForCodeCompletion(swift::constraints::SyntacticElementTarget&, bool, llvm::function_ref<void (swift::constraints::Solution const&)>)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a {
+arr: ] func b {
+return c
+{
+before#^^#? arr : }
+<
diff --git a/validation-test/IDE/crashers_fixed/4e946c4a77ce8d.swift b/validation-test/IDE/crashers_fixed/4e946c4a77ce8d.swift
new file mode 100644
index 0000000000000..65b327bed1b76
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/4e946c4a77ce8d.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::ide::CompletionLookup::getValueCompletionsInDeclContext(swift::SourceLoc, std::__1::function<bool (swift::ValueDecl*, swift::DeclVisibilityKind, swift::DynamicLookupInfo)>, bool, bool)"}
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -code-completion-diagnostics -source-filename %s
+for () [
+#^COMPLETE^#, (repeat.a
diff --git a/validation-test/IDE/crashers_fixed/4f698c426f7f9b.swift b/validation-test/IDE/crashers_fixed/4f698c426f7f9b.swift
new file mode 100644
index 0000000000000..7e155967faa1a
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/4f698c426f7f9b.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"03d6b22e","signature":"swift::TypeChecker::typeCheckForCodeCompletion(swift::constraints::SyntacticElementTarget&, bool, llvm::function_ref<void (swift::constraints::Solution const&)>)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func a->Int { ((0 + 0 + 0 + 0 4) << 1)#^^# <<
diff --git a/validation-test/IDE/crashers_fixed/539adae64314fae.swift b/validation-test/IDE/crashers_fixed/539adae64314fae.swift
new file mode 100644
index 0000000000000..c7c0c9146e1b2
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/539adae64314fae.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","signature":"void std::__1::__introsort<std::__1::_ClassicAlgPolicy, printCodeCompletionLookedupTypeNames(llvm::ArrayRef<swift::NullTerminatedStringRef>, llvm::raw_ostream&)::$_0&, swift::NullTerminatedStringRef*, false>(swift::NullTerminatedStringRef*, swift::NullTerminatedStringRef*, printCodeCompletionLookedupTypeNames(llvm::ArrayRef<swift::NullTerminatedStringRef>, llvm::raw_ostream&)::$_0&, std::__1::iterator_traits<swift::NullTerminatedStringRef*>::difference_type, bool)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a<each b: Collection
+{
+c: (repeat each b.Index
+func == {
+repeat each d == (each c)#^^#
diff --git a/validation-test/IDE/crashers_fixed/55f0ac4dba91c84.swift b/validation-test/IDE/crashers_fixed/55f0ac4dba91c84.swift
new file mode 100644
index 0000000000000..a10127c9531ce
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/55f0ac4dba91c84.swift
@@ -0,0 +1,9 @@
+// {"kind":"complete","original":"df6ac250","signature":"bool llvm::function_ref<bool (swift::constraints::Constraint*)>::callback_fn<swift::constraints::ConstraintSystem::simplifyAppliedOverloadsImpl(swift::constraints::Constraint*, swift::TypeVariableType*, swift::FunctionType*, unsigned int, swift::constraints::ConstraintLocatorBuilder)::$_2>(long, swift::constraints::Constraint*)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a {
+b func b()
+  #if {
+    b(<#expression#>)
+  }#^^#
+  #endif
+}
diff --git a/validation-test/IDE/crashers_fixed/59ed4db5bf91f452.swift b/validation-test/IDE/crashers_fixed/59ed4db5bf91f452.swift
new file mode 100644
index 0000000000000..ae82b85cd4fde
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/59ed4db5bf91f452.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"089853e1","signature":"swift::TypeChecker::typeCheckForCodeCompletion(swift::constraints::SyntacticElementTarget&, bool, llvm::function_ref<void (swift::constraints::Solution const&)>)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a {
+b:
+func c -> UInt32 {
+0 ^ b#^^#
diff --git a/validation-test/IDE/crashers_fixed/617a2713e6cd3627.swift b/validation-test/IDE/crashers_fixed/617a2713e6cd3627.swift
new file mode 100644
index 0000000000000..3b6e697d70749
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/617a2713e6cd3627.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"3de07705","signature":"swift::ide::PostfixCompletionCallback::Result::tryMerge(swift::ide::PostfixCompletionCallback::Result const&, swift::DeclContext*)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+2 ?? .map {} #^^#?? a
diff --git a/validation-test/IDE/crashers_fixed/63cae8d8f799869.swift b/validation-test/IDE/crashers_fixed/63cae8d8f799869.swift
new file mode 100644
index 0000000000000..c5c967c3ac3c9
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/63cae8d8f799869.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","original":"8d3b43e5","signature":"(anonymous namespace)::ConstraintWalker::walkToExprPost(swift::Expr*)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+[
+  switch  {
+  case ((\.a) #^^#
+  , .b,
diff --git a/validation-test/IDE/crashers_fixed/6492c324dc6bdc2.swift b/validation-test/IDE/crashers_fixed/6492c324dc6bdc2.swift
new file mode 100644
index 0000000000000..8b7109ab7f785
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/6492c324dc6bdc2.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::ide::AfterPoundExprCompletion::sawSolutionImpl(swift::constraints::Solution const&)"}
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -source-filename %s
+a ##^COMPLETE^# / ( b/bin/c
diff --git a/validation-test/IDE/crashers_fixed/6cef534b98d6b512.swift b/validation-test/IDE/crashers_fixed/6cef534b98d6b512.swift
new file mode 100644
index 0000000000000..de5390a76e32b
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/6cef534b98d6b512.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::constraints::Solution::simplifyType(swift::Type, bool) const"}
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -code-completion-diagnostics -source-filename %s
+for (a(b, d)) [
+#^COMPLETE^#, 0, (repeat.c)].enumerated(
diff --git a/validation-test/IDE/crashers_fixed/700c7172dd0e486.swift b/validation-test/IDE/crashers_fixed/700c7172dd0e486.swift
new file mode 100644
index 0000000000000..665e4e1c41385
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/700c7172dd0e486.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::ide::PostfixCompletionCallback::Result::tryMerge(swift::ide::PostfixCompletionCallback::Result const&, swift::DeclContext*)"}
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -code-completion-diagnostics -source-filename %s
+Int { switch { case Optional.some()#^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/7068664dc48e3152.swift b/validation-test/IDE/crashers_fixed/7068664dc48e3152.swift
new file mode 100644
index 0000000000000..033bef753c513
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/7068664dc48e3152.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::ide::CodeCompletionResultType::calculateTypeRelation(swift::ide::ExpectedTypeContext const*, swift::DeclContext const*, swift::ide::USRBasedTypeContext const*) const"}
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -source-filename %s
+class a<b { init ? { #^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/70921c2dbc55979.swift b/validation-test/IDE/crashers_fixed/70921c2dbc55979.swift
new file mode 100644
index 0000000000000..1940774fdd423
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/70921c2dbc55979.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","signature":"swift::irgen::IRGenModule::emitLazyObjCProtocolDefinition(swift::ProtocolDecl*)"}
+// Actual signature: matchCallArguments
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -source-filename %s
+a(
+#^COMPLETE^#[
+""!
diff --git a/validation-test/IDE/crashers_fixed/7361e81dcc17636c.swift b/validation-test/IDE/crashers_fixed/7361e81dcc17636c.swift
new file mode 100644
index 0000000000000..b581c17fbf037
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/7361e81dcc17636c.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::constraints::TypeVarRefCollector::walkToStmtPre(swift::Stmt*)","signatureAssert":"Assertion failed: (result), function getClosureType"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+a -> { let b = switch { case return } func c -> #^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/7b2825e90bfce47.swift b/validation-test/IDE/crashers_fixed/7b2825e90bfce47.swift
new file mode 100644
index 0000000000000..0b015a60019e1
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/7b2825e90bfce47.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"swift::SourceManager::findBufferContainingLocInternal(swift::SourceLoc) const","signatureAssert":"Assertion failed: (Loc.isValid()), function findBufferContainingLocInternal"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+class a { lazy b: () = { answer {}#^^#
diff --git a/validation-test/IDE/crashers_fixed/7dfd3dd444f43abb.swift b/validation-test/IDE/crashers_fixed/7dfd3dd444f43abb.swift
new file mode 100644
index 0000000000000..3531e27a486ee
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/7dfd3dd444f43abb.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::TypeBase::isEqual(swift::Type) const"}
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -code-completion-diagnostics -source-filename %s
+Set(
+##^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/7dfeb692d885c8c5.swift b/validation-test/IDE/crashers_fixed/7dfeb692d885c8c5.swift
new file mode 100644
index 0000000000000..272bcf9e73069
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/7dfeb692d885c8c5.swift
@@ -0,0 +1,9 @@
+// {"kind":"complete","original":"0bd7af1f","signature":"swift::constraints::TypeVarRefCollector::walkToStmtPre(swift::Stmt*)","signatureAssert":"Assertion failed: (result), function getClosureType"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{
+  let a =
+    if <#expression#> {
+      return
+    }
+  return #^^#
+}
diff --git a/validation-test/IDE/crashers_fixed/928f167118f85cf.swift b/validation-test/IDE/crashers_fixed/928f167118f85cf.swift
new file mode 100644
index 0000000000000..5f9044dbcc58f
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/928f167118f85cf.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"7bbb1dc5","signature":"swift::TypeRepr::print(swift::ASTPrinter&, swift::PrintOptions const&, swift::optionset::OptionSet<swift::NonRecursivePrintOption, unsigned int>) const","signatureAssert":"Assertion failed: (false && \"Expression wasn't type checked?\"), function getTypeForCompletion"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+a ? {
+init { b { extension
+}#^^#
diff --git a/validation-test/IDE/crashers_fixed/934bb97a5cbe0b8.swift b/validation-test/IDE/crashers_fixed/934bb97a5cbe0b8.swift
new file mode 100644
index 0000000000000..236602fc0c0fa
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/934bb97a5cbe0b8.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","original":"a705fa0d","signature":"swift::constraints::Solution::simplifyType(swift::Type, bool) const","signatureAssert":"Assertion failed: (!resolvedType->getRecursiveProperties().isSolverAllocated()), function simplifyType"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{
+  $1 {
+  }(
+    #^^#)
+}
diff --git a/validation-test/IDE/crashers_fixed/a1e970213e6f919d.swift b/validation-test/IDE/crashers_fixed/a1e970213e6f919d.swift
new file mode 100644
index 0000000000000..0fef9876f8107
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/a1e970213e6f919d.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","original":"158bd92d","signature":"swift::TypeTransform<swift::Type::transformRec(llvm::function_ref<std::__1::optional<swift::Type> (swift::TypeBase*)>) const::Transform>::doIt(swift::Type, swift::TypePosition)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a<b > : c protocol d { associatedtype b }
+protocol c: d where b: e protocol f { associatedtype g: d associatedtype b}
+protocol h: f where g == a<b> protocol i : f protocol e { associatedtype j: i
+#^^#
+associatedtype k: h where k.b == j.b
diff --git a/validation-test/IDE/crashers_fixed/ab16c0e38dae31b3.swift b/validation-test/IDE/crashers_fixed/ab16c0e38dae31b3.swift
new file mode 100644
index 0000000000000..9bdd46de65329
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/ab16c0e38dae31b3.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::Mangle::ASTMangler::appendType(swift::Type, swift::GenericSignature, swift::ValueDecl const*)"}
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -source-filename %s
+func a<let b
+#^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/ad7672295e2e882c.swift b/validation-test/IDE/crashers_fixed/ad7672295e2e882c.swift
new file mode 100644
index 0000000000000..43dedf2c60f88
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/ad7672295e2e882c.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::ide::CodeCompletionResultType::calculateTypeRelation(swift::ide::ExpectedTypeContext const*, swift::DeclContext const*, swift::ide::USRBasedTypeContext const*) const"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func b(a : Array<Int>) {
+let: Array = a.prefix( #^^#
diff --git a/validation-test/IDE/crashers_fixed/b4e591f09ce81b0.swift b/validation-test/IDE/crashers_fixed/b4e591f09ce81b0.swift
new file mode 100644
index 0000000000000..e41ae8ec3e8f0
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/b4e591f09ce81b0.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","original":"0b319c77","signature":"swift::ExtensionDecl::getExtendedNominal() const","signatureAssert":"Extension must have already been bound"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension a[ {
+  #^^#
+}
diff --git a/validation-test/IDE/crashers_fixed/b59b74aac149f67f.swift b/validation-test/IDE/crashers_fixed/b59b74aac149f67f.swift
new file mode 100644
index 0000000000000..5ffafe8789efc
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/b59b74aac149f67f.swift
@@ -0,0 +1,5 @@
+// {"kind":"complete","signature":"swift::MetatypeType::get(swift::Type, std::__1::optional<swift::MetatypeRepresentation>, swift::ASTContext const&)"}
+// RUN: %target-swift-ide-test -code-completion --code-completion-token=COMPLETE -code-completion-diagnostics -source-filename %s
+[ .
+#^COMPLETE^#,
+( repeat.a ), (3, .b
diff --git a/validation-test/IDE/crashers_fixed/ba845eb07913ee41.swift b/validation-test/IDE/crashers_fixed/ba845eb07913ee41.swift
new file mode 100644
index 0000000000000..0306b20b16645
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/ba845eb07913ee41.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","signature":"void std::__1::__introsort<std::__1::_ClassicAlgPolicy, printCodeCompletionLookedupTypeNames(llvm::ArrayRef<swift::NullTerminatedStringRef>, llvm::raw_ostream&)::$_0&, swift::NullTerminatedStringRef*, false>(swift::NullTerminatedStringRef*, swift::NullTerminatedStringRef*, printCodeCompletionLookedupTypeNames(llvm::ArrayRef<swift::NullTerminatedStringRef>, llvm::raw_ostream&)::$_0&, std::__1::iterator_traits<swift::NullTerminatedStringRef*>::difference_type, bool)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+(.1.a - a)#^^#
diff --git a/validation-test/IDE/crashers_fixed/bfc920b5867dcc4c.swift b/validation-test/IDE/crashers_fixed/bfc920b5867dcc4c.swift
new file mode 100644
index 0000000000000..b2dc41c9cf1b2
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/bfc920b5867dcc4c.swift
@@ -0,0 +1,7 @@
+// {"kind":"complete","original":"03137cdb","signature":"swift::constraints::ConstraintSystem::applySolution(swift::constraints::Solution&, swift::constraints::SyntacticElementTarget)","signatureAssert":"Assertion failed: (isValidType(type) && \"type binding has invalid type\"), function applySolution"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@propertyWrapper struct a<b {
+  wrappedValue: b
+}
+{
+  @a var c #^^#
diff --git a/validation-test/IDE/crashers_fixed/c9b7522368139eb7.swift b/validation-test/IDE/crashers_fixed/c9b7522368139eb7.swift
new file mode 100644
index 0000000000000..a8aec6f709659
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/c9b7522368139eb7.swift
@@ -0,0 +1,8 @@
+// {"kind":"complete","original":"ad5b343d","signature":"swift::InterfaceTypeRequest::cacheResult(swift::Type) const","signatureAssert":"Assertion failed: (!type->is<InOutType>() && \"Interface type must be materializable\"), function cacheResult"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+[
+  #^^#
+].reduce?(
+  [:][0] {
+    $a, b in
+  })
diff --git a/validation-test/IDE/crashers_fixed/ce6e7a44344828a0.swift b/validation-test/IDE/crashers_fixed/ce6e7a44344828a0.swift
new file mode 100644
index 0000000000000..64f07d0c0af4d
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/ce6e7a44344828a0.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","signature":"(anonymous namespace)::ConstraintWalker::walkToExprPost(swift::Expr*)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+enum a }
+{
+var b: a func c { switch b {
+#^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/d73ece80c892d352.swift b/validation-test/IDE/crashers_fixed/d73ece80c892d352.swift
new file mode 100644
index 0000000000000..16b0af4f60bd4
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/d73ece80c892d352.swift
@@ -0,0 +1,10 @@
+// {"kind":"complete","original":"00db48f7","signature":"swift::TypeChecker::typeCheckForCodeCompletion(swift::constraints::SyntacticElementTarget&, bool, llvm::function_ref<void (swift::constraints::Solution const&)>)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+struct a {
+  arr: ]  func b() {
+    return c {
+      (#^^# ? arr : <#expression#>)
+    }
+      < <#expression#>
+  }
+}
diff --git a/validation-test/IDE/crashers_fixed/d9ea33a8feaee63c.swift b/validation-test/IDE/crashers_fixed/d9ea33a8feaee63c.swift
new file mode 100644
index 0000000000000..0adea35ab82d9
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/d9ea33a8feaee63c.swift
@@ -0,0 +1,3 @@
+// {"kind":"complete","original":"d09c9cf7","signature":"swift::Mangle::ASTMangler::mangleTypeAsUSR(swift::Type)"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+try #^^# ?? (try? a.() as? b)
diff --git a/validation-test/IDE/crashers_fixed/dc8881dce3e968b.swift b/validation-test/IDE/crashers_fixed/dc8881dce3e968b.swift
new file mode 100644
index 0000000000000..2fde9c04ed9d4
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/dc8881dce3e968b.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","original":"6384b7fc","signature":"swift::TypeChecker::typeCheckForCodeCompletion(swift::constraints::SyntacticElementTarget&, bool, llvm::function_ref<void (swift::constraints::Solution const&)>)","signatureAssert":"Assertion failed: (fallback->E != expr), function typeCheckForCodeCompletion"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+func a -> b
+a > (c > a #^^# )'
diff --git a/validation-test/IDE/crashers_fixed/e6f077eee83be8a7.swift b/validation-test/IDE/crashers_fixed/e6f077eee83be8a7.swift
new file mode 100644
index 0000000000000..11afb7c433636
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/e6f077eee83be8a7.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"swift::constraints::ConstraintSystem::getType(swift::ASTNode) const","signatureAssert":"Assertion failed: (!node.isNull() && \"Expected non-null node\"), function hasType"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+if case (
+#a,#^COMPLETE^# is b
diff --git a/validation-test/IDE/crashers_fixed/e7327cfd8bafcd86.swift b/validation-test/IDE/crashers_fixed/e7327cfd8bafcd86.swift
new file mode 100644
index 0000000000000..8423f8cac3b42
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/e7327cfd8bafcd86.swift
@@ -0,0 +1,10 @@
+// {"kind":"complete","original":"bc7ab9d8","signature":"swift::constraints::ConstraintSystem::getTypeOfReference(swift::ValueDecl*, swift::FunctionRefInfo, swift::constraints::ConstraintLocatorBuilder, swift::DeclContext*, swift::constraints::PreparedOverloadBuilder*)","signatureAssert":"Assertion failed: (func->isOperator() && \"Lookup should only find operators\"), function getTypeOfReference"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+{
+  func a(query: String) {
+    {
+      "\(query)"
+      break #^^#
+    }
+  }
+}
diff --git a/validation-test/IDE/crashers_fixed/ebec93dfd96612ef.swift b/validation-test/IDE/crashers_fixed/ebec93dfd96612ef.swift
new file mode 100644
index 0000000000000..c26115b3ebd24
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/ebec93dfd96612ef.swift
@@ -0,0 +1,6 @@
+// {"kind":"complete","signature":"(anonymous namespace)::ConstraintWalker::walkToExprPost(swift::Expr*)","signatureAssert":"Assertion failed: (!ty->is<InOutType>() && \"Cannot have InOutType in a tuple\"), function TupleTypeElt"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+-switch  {
+case
+< (&a
+#^^#
diff --git a/validation-test/IDE/crashers_fixed/f1328ad669bd7cf8.swift b/validation-test/IDE/crashers_fixed/f1328ad669bd7cf8.swift
new file mode 100644
index 0000000000000..65b74766ca615
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/f1328ad669bd7cf8.swift
@@ -0,0 +1,4 @@
+// {"kind":"complete","signature":"Extension must have already been bound","signatureAssert":"Extension must have already been bound"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+extension a [ { func b {
+#^COMPLETE^#
diff --git a/validation-test/IDE/crashers_fixed/fd52bd37cd5c96.swift b/validation-test/IDE/crashers_fixed/fd52bd37cd5c96.swift
new file mode 100644
index 0000000000000..4c7bd628394a9
--- /dev/null
+++ b/validation-test/IDE/crashers_fixed/fd52bd37cd5c96.swift
@@ -0,0 +1,8 @@
+// {"kind":"complete","original":"ea806f48","signature":"swift::Type::transformRec(llvm::function_ref<std::__1::optional<swift::Type> (swift::TypeBase*)>) const"}
+// RUN: %target-swift-ide-test -code-completion -batch-code-completion -skip-filecheck -code-completion-diagnostics -source-filename %s
+@dynamicMemberLookup
+struct a<b{
+c: () -> b^subscript<d>(dynamicMember e: WritableKeyPath<b, d>) a<d> }
+let binding = a
+{ buffer #^^#??
+binding.0
diff --git a/validation-test/IDE/issues_fixed/issue-75845.swift b/validation-test/IDE/issues_fixed/issue-75845.swift
new file mode 100644
index 0000000000000..c4769cc794dc5
--- /dev/null
+++ b/validation-test/IDE/issues_fixed/issue-75845.swift
@@ -0,0 +1,42 @@
+// RUN: %batch-code-completion
+
+// https://github.com/apple/swift/issues/75845
+// Make sure we don't crash.
+
+struct Foo {
+  init() {
+    do {
+    } catch {
+      #^A^#self#^B^# = #^C^#error#^D^#
+    }
+  }
+}
+// A: Decl[LocalVar]/Local: error[#any Error#]; name=error
+// B: Begin completions
+// C: Decl[LocalVar]/Local: error[#any Error#]; name=error
+// D: Begin completions
+
+enum E {
+  case e(Error)
+
+  func foo() {
+    var x = self
+    do {
+    } catch {
+      x = .e(error)#^E^#
+      // E: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: .foo()[#Void#]; name=foo()
+    }
+  }
+
+  static func bar() {
+    do {
+    } catch {
+      _ = foo(.e(error))#^F^#
+      // F: Decl[InstanceMethod]/CurrNominal/Flair[ArgLabels]: ()[#Void#]; name=()
+
+      _ = foo(.e(error))()#^G^#
+      // G: Begin completions, 1 items
+      // G: Keyword[self]/CurrNominal: .self[#Void#]; name=self
+    }
+  }
+}
diff --git a/validation-test/IDE/issues_fixed/rdar149032713.swift b/validation-test/IDE/issues_fixed/rdar149032713.swift
new file mode 100644
index 0000000000000..0af24f687f190
--- /dev/null
+++ b/validation-test/IDE/issues_fixed/rdar149032713.swift
@@ -0,0 +1,4 @@
+// RUN: %target-swift-ide-test -print-swift-file-interface -source-filename %s
+
+@available(*, unavailable)
+extension Foo {}
diff --git a/validation-test/IDE/issues_fixed/rdar63063279.swift b/validation-test/IDE/issues_fixed/rdar63063279.swift
index 1e687684f4b48..e415e42c9fd54 100644
--- a/validation-test/IDE/issues_fixed/rdar63063279.swift
+++ b/validation-test/IDE/issues_fixed/rdar63063279.swift
@@ -61,4 +61,4 @@ D().b(b: .#^B_5?check=B^#)
 // B: Begin completions, 3 items
 // B-DAG: Decl[Constructor]/CurrNominal/TypeRelation[Convertible]: init({#(value): T#})[#B<T>#]; name=init(:)
 // B-DAG: Decl[StaticMethod]/CurrNominal/TypeRelation[Convertible]: void()[#B<Void>#]; name=void()
-// B-DAG: Decl[StaticMethod]/CurrNominal:     data({#(data): <<error type>>#})[#<<error type>>#]; name=data(:)
+// B-DAG: Decl[StaticMethod]/CurrNominal:     data({#(data): _#})[#_#]; name=data(:)
diff --git a/validation-test/IDE/stress_tester_issues_fixed/issue-80591.swift b/validation-test/IDE/stress_tester_issues_fixed/issue-80591.swift
new file mode 100644
index 0000000000000..fd5cb8ac9bfa1
--- /dev/null
+++ b/validation-test/IDE/stress_tester_issues_fixed/issue-80591.swift
@@ -0,0 +1,9 @@
+// RUN: %batch-code-completion
+
+// https://github.com/apple/swift/issues/80591
+
+// Just make sure we don't crash.
+var foo: Bool {
+  baz == .#^COMPLETE^#
+  // COMPLETE: Begin completions
+}
diff --git a/validation-test/IDE/stress_tester_issues_fixed/pr-81028.swift b/validation-test/IDE/stress_tester_issues_fixed/pr-81028.swift
new file mode 100644
index 0000000000000..b168fc6642c5e
--- /dev/null
+++ b/validation-test/IDE/stress_tester_issues_fixed/pr-81028.swift
@@ -0,0 +1,9 @@
+// RUN: %batch-code-completion
+
+// Make sure we don't crash.
+func foo(xs: [[Int]], ys: [Int]) {
+    for x in ys {
+      _ = xs.map{ $0.filter{ $0 == x } #^COMPLETE^# }
+      // COMPLETE: Begin completions
+    }
+}
diff --git a/validation-test/IRGen/rdar147207926.swift b/validation-test/IRGen/rdar147207926.swift
new file mode 100644
index 0000000000000..36335d517ad24
--- /dev/null
+++ b/validation-test/IRGen/rdar147207926.swift
@@ -0,0 +1,65 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend                              \
+// RUN:     %t/Library.swift                                \
+// RUN:     -emit-module                                    \
+// RUN:     -target %target-swift-5.9-abi-triple            \
+// RUN:     -enable-library-evolution                       \
+// RUN:     -module-name Library                            \
+// RUN:     -emit-module-path %t/Library.swiftmodule
+
+// RUN: %target-build-swift                                 \
+// RUN:     %t/Downstream.swift                             \
+// RUN:     -c                                              \
+// RUN:     -target %target-swift-5.9-abi-triple            \
+// RUN:     -parse-as-library                               \
+// RUN:     -module-name main                               \
+// RUN:     -lLibrary                                       \
+// RUN:     -I %t                                           \
+// RUN:     -o %t/Executable.o
+
+//--- Library.swift
+
+public struct Paq<each T> {
+  public var uette: (repeat each T)
+}
+
+public class Loq<each T> {
+}
+
+// Enums don't take packs yet.
+
+// public enum Orq<each T> {
+//   case uette(repeat each T)
+//   case uettette(repeat each T, repeat each T)
+// }
+
+//--- Downstream.swift
+
+import Library
+
+struct Sleeve<T> {
+  var impl: Paq<T>
+}
+
+func bin<Moribund>(_ s: consuming Sleeve<Moribund>) {
+}
+
+struct Laq<T> {
+  var impl: Loq<T>
+  var t: T
+}
+
+@_silgen_name("bun")
+func bun<T>(_ l: consuming Laq<T>) {
+}
+
+// Enums don't take packs yet.
+
+// struct Etiq<T> {
+//   var impl: Orq<T>
+// }
+// 
+// func bon<Moribund>(_ i: consuming Etiq<Moribund>) {
+// }
diff --git a/validation-test/IRGen/rdar149985633.swift b/validation-test/IRGen/rdar149985633.swift
new file mode 100644
index 0000000000000..3ab9b20551c3a
--- /dev/null
+++ b/validation-test/IRGen/rdar149985633.swift
@@ -0,0 +1,49 @@
+// RUN: %target-swift-frontend -O -emit-ir %s | %FileCheck %s
+
+// REQUIRES: PTRSIZE=64
+
+// CHECK: define {{.*}}swiftcc void @"$s13rdar1499856334DateV1a1b1c1d1e1fACSiSg_A5JtcfC"(ptr noalias{{( nocapture)?}} writeonly sret(%T13rdar1499856334DateV){{( captures\(none\))?}}{{.*}} %0, i64 %1, i8 %2, i64 %3, i8 %4, i64 %5, i8 %6, i64 %7, i8 %8, i64 %9, i8 %10, i64 %11, i8 %12)
+// CHECK: entry:
+// CHECK:   store i64 %1
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 8
+// CHECK:   store i8 %2
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 16
+// CHECK:   store i64 %3
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 24
+// CHECK:   store i8 %4
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 32
+// CHECK:   store i64 %5
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 40
+// CHECK:   store i8 %6
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 48
+// CHECK:   store i64 %7
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 56
+// CHECK:   store i8 %8
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 64
+// CHECK:   store i64 %9
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 72
+// CHECK:   store i8 %10
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 80
+// CHECK:   store i64 %11
+// CHECK:   getelementptr inbounds{{.*}} i8, ptr %0, i64 88
+// CHECK:   store i8 %12
+// CHECK:   ret void
+// CHECK: }
+
+public struct Date {
+    internal var a: Int?
+    internal var b: Int?
+    internal var c: Int?
+    internal var d: Int?
+    internal var e: Int?
+    internal var f: Int?
+
+    public init(a: Int?, b: Int?, c: Int?, d: Int?, e: Int?, f: Int?) {
+        self.a = a
+        self.b = b
+        self.c = c
+        self.d = d
+        self.e = e
+        self.f = f
+    }
+}
diff --git a/validation-test/IRGen/rdar151726387.sil b/validation-test/IRGen/rdar151726387.sil
new file mode 100644
index 0000000000000..4ab2419ceae05
--- /dev/null
+++ b/validation-test/IRGen/rdar151726387.sil
@@ -0,0 +1,21 @@
+// RUN: %target-swift-frontend -parse-sil -emit-ir %s
+
+sil_stage canonical
+
+import Builtin
+import Swift
+
+struct O {
+  var arr: Builtin.FixedArray<1, I>
+  struct I {
+    var eyes: SIMD64<Int8>
+    var neighs: String
+  }
+}
+
+sil @copy : $@convention(thin) (@in_guaranteed O) -> (@out O) {
+entry(%out : $*O, %in : $*O):
+  copy_addr %in to [init] %out : $*O
+  %retval = tuple ()
+  return %retval : $()
+}
diff --git a/validation-test/IRGen/rdar152580661.swift b/validation-test/IRGen/rdar152580661.swift
new file mode 100644
index 0000000000000..1b1ed7e68897e
--- /dev/null
+++ b/validation-test/IRGen/rdar152580661.swift
@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend %s -target %target-swift-5.9-abi-triple -emit-ir
+
+struct H<T> {
+  var packs: [Pack<T>] {
+      id(_packs)
+  }
+  let _packs: [Pack<T>]
+}
+
+struct Pack<each T> {}
+
+func id<T>(_ t: T) -> T {
+  return t
+}
diff --git a/validation-test/IRGen/rdar153681688.swift b/validation-test/IRGen/rdar153681688.swift
new file mode 100644
index 0000000000000..4dddb886313fa
--- /dev/null
+++ b/validation-test/IRGen/rdar153681688.swift
@@ -0,0 +1,8 @@
+// RUN: %target-swift-frontend %s -target %target-swift-5.9-abi-triple -emit-ir
+
+public enum Enum<T : ~Escapable> : ~Escapable {
+  case none
+  case some(T)
+}
+
+extension Enum: Escapable where T: Escapable {}
diff --git a/validation-test/IRGen/rdar158083136.swift b/validation-test/IRGen/rdar158083136.swift
new file mode 100644
index 0000000000000..6ead7a42def9d
--- /dev/null
+++ b/validation-test/IRGen/rdar158083136.swift
@@ -0,0 +1,6 @@
+// RUN: %target-swift-frontend %s -disable-availability-checking -emit-ir
+
+func f<let i: Int, T>(
+    _: consuming InlineArray<i, (String, T)>
+) {
+}
diff --git a/validation-test/IRGen/rdar161606892.swift b/validation-test/IRGen/rdar161606892.swift
new file mode 100644
index 0000000000000..01e01c685f068
--- /dev/null
+++ b/validation-test/IRGen/rdar161606892.swift
@@ -0,0 +1,8 @@
+// RUN: %target-swift-frontend %s -target %target-swift-5.9-abi-triple -emit-irgen | %IRGenFileCheck %s
+
+// CHECK: Attrs: noinline nounwind{{$}}
+// CHECK-NEXT: define {{.*}}@"$s13rdar1616068921PVMa"
+
+public struct P<each T> {
+  public var teas: (repeat each T)
+}
diff --git a/validation-test/IRGen/rdar161606892_2.swift b/validation-test/IRGen/rdar161606892_2.swift
new file mode 100644
index 0000000000000..2651d0d7ef53f
--- /dev/null
+++ b/validation-test/IRGen/rdar161606892_2.swift
@@ -0,0 +1,40 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-build-swift \
+// RUN:     -emit-module \
+// RUN:     -target %target-swift-5.9-abi-triple \
+// RUN:     %t/Library.swift \
+// RUN:     -parse-as-library \
+// RUN:     -module-name Library \
+// RUN:     -emit-module-path %t/Library.swiftmodule
+
+// RUN: %target-swift-frontend                              \
+// RUN:     %t/Downstream.swift                             \
+// RUN:     -emit-irgen                                     \
+// RUN:     -target %target-swift-5.9-abi-triple            \
+// RUN:     -module-name main                               \
+// RUN:     -lLibrary                                       \
+// RUN:     -I %t                                           \
+// RUN: | %FileCheck %t/Downstream.swift --check-prefixes=CHECK,CHECK-OLD
+
+//--- Library.swift
+
+public struct Pack<each T> {
+  public init() {}
+}
+
+public func sink<T>(_ t: T) {}
+
+//--- Downstream.swift
+
+import Library
+
+// CHECK: doit
+// CHECK: @"$s7Library4PackVMa"{{.*}} [[CALL:#[^,]+]]
+
+// CHECK: attributes [[CALL]] = { nounwind memory(argmem: readwrite, inaccessiblemem: readwrite) }
+@_silgen_name("doit")
+func doit<each T, each U>(ts: repeat each T, us: repeat each U) {
+  sink(Pack<repeat each T, repeat each U>())
+}
diff --git a/validation-test/ParseableInterface/verify_all_overlays.py b/validation-test/ParseableInterface/verify_all_overlays.py
index 1241a85736056..2664fa52e43cc 100755
--- a/validation-test/ParseableInterface/verify_all_overlays.py
+++ b/validation-test/ParseableInterface/verify_all_overlays.py
@@ -48,6 +48,7 @@
         "SwiftLang",
         # swiftCxxStdlib uses `-module-interface-preserve-types-as-written`
         "CxxStdlib",
+        "CompatibilitySpan",
     ]:
         continue
 
diff --git a/validation-test/SILOptimizer/gh81515.swift b/validation-test/SILOptimizer/gh81515.swift
new file mode 100644
index 0000000000000..f097ce830103e
--- /dev/null
+++ b/validation-test/SILOptimizer/gh81515.swift
@@ -0,0 +1,36 @@
+// RUN: %target-build-swift %s
+
+typealias LeagueDayOfWeek = UInt8
+
+let settings = LeagueSettings(divisions: [.init(id: 0, dayOfWeek: 0), .init(id: 1, dayOfWeek: 0)])
+let dummy = Dummy()
+dummy.dummy(settings: settings)
+
+struct LeagueSettings: Codable, Sendable {
+    let divisions:ContiguousArray<LeagueDivision>
+}
+struct LeagueEntry: Codable, Sendable {
+    typealias IDValue = Int
+}
+struct LeagueDivision: Codable, Hashable, Sendable {
+    typealias IDValue = Int
+    let id:IDValue
+    let dayOfWeek:LeagueDayOfWeek
+}
+struct Dummy: ~Copyable {
+}
+extension Dummy {
+    func dummy(settings: LeagueSettings) {
+        var divisionEntries:ContiguousArray<Set<LeagueEntry.IDValue>> = .init(repeating: Set(), count: settings.divisions.count)
+        var grouped:[LeagueDayOfWeek:Set<LeagueEntry.IDValue>] = [:]
+        for division in settings.divisions {
+            /* // OK
+            if grouped[division.dayOfWeek] == nil {
+                grouped[division.dayOfWeek] = divisionEntries[division.id]
+            } else {
+                grouped[division.dayOfWeek]!.formUnion(divisionEntries[division.id])
+            }*/
+            grouped[division.dayOfWeek, default: []].formUnion(divisionEntries[division.id]) // crashes
+        }
+    }
+}
diff --git a/validation-test/SILOptimizer/gh84337.swift b/validation-test/SILOptimizer/gh84337.swift
new file mode 100644
index 0000000000000..ea29e12d41258
--- /dev/null
+++ b/validation-test/SILOptimizer/gh84337.swift
@@ -0,0 +1,38 @@
+// RUN: %target-build-swift -O %s
+
+@propertyWrapper
+public struct Dependency2<Value> {
+  public init(
+    _ keyPath: KeyPath<DependencyValues, Value>
+  ) {
+
+  }
+  public var wrappedValue: Value {
+      let any: Any = "somestring"
+      return any as! Value
+  }
+}
+
+struct Client {
+    var get: (_ id: String) -> Bool
+}
+
+public struct DependencyValues {
+    var client3: Client
+}
+
+public protocol WindowData2 {
+    var id :String {get set}
+}
+
+extension WindowData2 {
+    func didSetProfileForSpaceIDs(
+        spaceIDs: [String]
+    ) -> Void {
+        @Dependency2(\.client3) var client: Client
+        spaceIDs.forEach { _ in
+            spaceIDs
+                .map { _ in return client.get(id) }
+        }
+    }
+}
diff --git a/validation-test/SILOptimizer/hoist_destroy_addr.sil b/validation-test/SILOptimizer/hoist_destroy_addr.sil
deleted file mode 100644
index 049b19752f31a..0000000000000
--- a/validation-test/SILOptimizer/hoist_destroy_addr.sil
+++ /dev/null
@@ -1,2300 +0,0 @@
-// RUN: %target-sil-opt -opt-mode=none  -enable-sil-verify-all %s -destroy-addr-hoisting | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECKDEB
-// RUN: %target-sil-opt -opt-mode=speed -enable-sil-verify-all %s -destroy-addr-hoisting | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECKOPT
-
-// REQUIRES: rdar98890125
-// REQUIRES: long_test
-// REQUIRES: objc_interop
-// SIL includes assumption of 64-bit wordsize
-// REQUIRES: PTRSIZE=64
-
-import Builtin
-import Swift
-import SwiftShims
-
-sil [ossa] @$s10Foundation4DataV06InlineB0Vys5UInt8VSicis : $@convention(method) (UInt8, Int, @inout Data.InlineData) -> ()
-sil [ossa] @$s10Foundation4DataV10LargeSliceVys5UInt8VSicis : $@convention(method) (UInt8, Int, @inout Data.LargeSlice) -> ()
-sil [ossa] @$s10Foundation4DataV11InlineSliceVys5UInt8VSicis : $@convention(method) (UInt8, Int, @inout Data.InlineSlice) -> ()
-sil [ossa] @$sSMsSKRzrlE7reverseyyF : $@convention(method) <τ_0_0 where τ_0_0 : BidirectionalCollection, τ_0_0 : MutableCollection> (@inout τ_0_0) -> ()
-sil [ossa] @$sSMsSKRzrlE7reverseyyFSays5UInt8VG_Tg5 : $@convention(method) (@inout Array<UInt8>) -> ()
-sil [ossa] @$sSN16_uncheckedBoundsSNyxGx5lower_x5uppert_tcfC : $@convention(method) <τ_0_0 where τ_0_0 : Comparable> (@in τ_0_0, @in τ_0_0, @thin ClosedRange<τ_0_0>.Type) -> @out ClosedRange<τ_0_0>
-sil [ossa] @$sSR5start5countSRyxGSPyxGSg_SitcfCs5UInt8V_Tg5 : $@convention(method) (Optional<UnsafePointer<UInt8>>, Int, @thin UnsafeBufferPointer<UInt8>.Type) -> UnsafeBufferPointer<UInt8>
-sil [ossa] @$sSRys5UInt8VGSSs5Error_pIgyozo_ACSSsAD_pIegyrzo_TR : $@convention(thin) (UnsafeBufferPointer<UInt8>, @noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> (@owned String, @error Error)) -> (@out String, @error Error)
-sil [ossa] @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
-sil [ossa] @$sSUss17FixedWidthIntegerRzrlEyxqd__cSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger, τ_0_0 : UnsignedInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-sil [ossa] @$sSXsE2teoiySbx_5BoundQztFZ : $@convention(method) <τ_0_0 where τ_0_0 : RangeExpression> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0.Bound, @thick τ_0_0.Type) -> Bool
-sil [ossa] @$sSZsE8isSignedSbvgZ : $@convention(method) <τ_0_0 where τ_0_0 : SignedInteger> (@thick τ_0_0.Type) -> Bool
-sil [ossa] @$sSZss17FixedWidthIntegerRzrlEyxqd__cSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger, τ_0_0 : SignedInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-sil [ossa] @$sSa034_makeUniqueAndReserveCapacityIfNotB0yyFs5UInt8V_Tg5 : $@convention(method) (@inout Array<UInt8>) -> ()
-sil [ossa] @$sSa12_endMutationyyFs5UInt8V_Tg5 : $@convention(method) (@inout Array<UInt8>) -> ()
-sil [ossa] @$sSa22_allocateUninitializedySayxG_SpyxGtSiFZs5UInt8V_Tg5 : $@convention(method) (Int, @thin Array<UInt8>.Type) -> (@owned Array<UInt8>, UnsafeMutablePointer<UInt8>)
-sil [ossa] @$sSa23withUnsafeBufferPointeryqd__qd__SRyxGKXEKlF : $@convention(method) <τ_0_0><τ_1_0> (@noescape @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0 == τ_0_1> (UnsafeBufferPointer<τ_0_0>) -> (@out τ_0_2, @error Error) for <τ_0_0, τ_0_0, τ_1_0>, @guaranteed Array<τ_0_0>) -> (@out τ_1_0, @error Error)
-sil [ossa] @$sSa36_reserveCapacityAssumingUniqueBuffer8oldCountySi_tFs5UInt8V_Tg5 : $@convention(method) (Int, @inout Array<UInt8>) -> ()
-sil [ossa] @$sSa37_appendElementAssumeUniqueAndCapacity_03newB0ySi_xntFs5UInt8V_Tg5 : $@convention(method) (Int, UInt8, @inout Array<UInt8>) -> ()
-sil [ossa] @$sSa6appendyyxnF : $@convention(method) <τ_0_0> (@in τ_0_0, @inout Array<τ_0_0>) -> ()
-sil [ossa] @$sSa6appendyyxnFs5UInt8V_Tg5 : $@convention(method) (UInt8, @inout Array<UInt8>) -> ()
-sil [ossa] @$sSlsE7isEmptySbvg : $@convention(method) <τ_0_0 where τ_0_0 : Collection> (@in_guaranteed τ_0_0) -> Bool
-sil [ossa] @$sSp14moveInitialize4from5countySpyxG_SitF : $@convention(method) <τ_0_0> (UnsafeMutablePointer<τ_0_0>, Int, UnsafeMutablePointer<τ_0_0>) -> ()
-sil [ossa] @$sSzsE12_description5radix9uppercaseSSSi_SbtF21_quotientAndRemainderL_y9MagnitudeQz_AFtAFSzRzlF : $@convention(thin) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0.Magnitude, Bool, Int, @in_guaranteed τ_0_0.Magnitude) -> (@out τ_0_0.Magnitude, @out τ_0_0.Magnitude)
-sil [ossa] @$sSzsE12_description5radix9uppercaseSSSi_SbtF6_asciiL_ys5UInt8VAFSzRzlF : $@convention(thin) (UInt8, Bool, Bool) -> UInt8
-sil [ossa] @$sSzsE12_description5radix9uppercaseSSSi_SbtFSSSRys5UInt8VGXEfU_ : $@convention(thin) (UnsafeBufferPointer<UInt8>) -> @owned String
-sil [ossa] @$ss12_ArrayBufferV19firstElementAddressSpyxGvgs5UInt8V_Tg5 : $@convention(method) (@guaranteed _ArrayBuffer<UInt8>) -> UnsafeMutablePointer<UInt8>
-sil [ossa] @$ss14_int64ToString_5radix9uppercaseSSs5Int64V_AESbtF : $@convention(thin) (Int64, Int64, Bool) -> @owned String
-sil [ossa] @$ss15_uint64ToString_5radix9uppercaseSSs6UInt64V_s5Int64VSbtF : $@convention(thin) (UInt64, Int64, Bool) -> @owned String
-sil [ossa] @$ss17FixedWidthIntegerPsE03bitB0Sivg : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger> (@in_guaranteed τ_0_0) -> Int
-sil [ossa] @$ss17FixedWidthIntegerPsE18truncatingIfNeededxqd___tcSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-sil [ossa] @$ss17_assertionFailure__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-sil [ossa] @$ss18_fatalErrorMessage__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-sil [ossa] @$ss18_growArrayCapacityyS2iF : $@convention(thin) (Int) -> Int
-sil [ossa] @$ss22_ContiguousArrayBufferV12mutableCountSivs : $@convention(method) <τ_0_0> (Int, @guaranteed _ContiguousArrayBuffer<τ_0_0>) -> ()
-sil [ossa] @$ss22_ContiguousArrayBufferV19_uninitializedCount15minimumCapacityAByxGSi_SitcfC : $@convention(method) <τ_0_0> (Int, Int, @thin _ContiguousArrayBuffer<τ_0_0>.Type) -> @owned _ContiguousArrayBuffer<τ_0_0>
-sil [ossa] @$ss22_ContiguousArrayBufferV19firstElementAddressSpyxGvg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
-sil [ossa] @$ss22_ContiguousArrayBufferV8capacitySivg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-sil [ossa] @$ss27_allocateUninitializedArrayySayxG_BptBwlF : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
-sil [ossa] @$ss3maxyxx_xtSLRzlF : $@convention(thin) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0) -> @out τ_0_0
-sil [ossa] @$ss48_UnsafePartiallyInitializedContiguousArrayBufferV23addWithExistingCapacityyyxF : $@convention(method) <τ_0_0> (@in_guaranteed τ_0_0, @inout _UnsafePartiallyInitializedContiguousArrayBuffer<τ_0_0>) -> ()
-sil [ossa] @$ss7UnicodeO6ScalarV5values6UInt32Vvg : $@convention(method) (Unicode.Scalar) -> UInt32
-
-struct Data {
-    internal enum _Representation {
-        case empty
-        case inline(InlineData)
-        case slice(InlineSlice)
-        case large(LargeSlice)
-    }
-    internal struct InlineData {
-        @usableFromInline typealias Buffer = (UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8,
-                                              UInt8, UInt8, UInt8, UInt8, UInt8, UInt8) //len  //enum
-        var bytes: Buffer
-        var length: UInt8
-    }
-    internal struct InlineSlice {
-        var slice: Range<HalfInt>
-        var storage: __DataStorage
-    }
-    internal final class __DataStorage {
-        var _bytes: UnsafeMutableRawPointer?
-        var _length: Int
-        var _capacity: Int
-        var _offset: Int
-        var _deallocator: ((UnsafeMutableRawPointer, Int) -> Void)?
-        var _needToZero: Bool
-    }
-    internal struct LargeSlice {
-        var slice: RangeReference
-        var storage: __DataStorage
-    }
-    internal final class RangeReference {
-        var range: Range<Int>
-    }
-    internal typealias HalfInt = Int32
-}
-
-sil [ossa] @getX : $@convention(thin) () -> @owned X 
-sil [ossa] @useX : $@convention(thin) (@owned X) -> ()  
-
-class X {}
-
-// CHECK-LABEL: sil [ossa] @hoist_over_loop_and_fold_into_load_copy : {{.*}} {
-// CHECK: load [take]
-// CHECK-LABEL: } // end sil function 'hoist_over_loop_and_fold_into_load_copy'
-sil [ossa] @hoist_over_loop_and_fold_into_load_copy : $@convention(thin) (@inout X) -> () {
-bb0(%0 : $*X):
- %1 = function_ref @getX : $@convention(thin) () -> @owned X 
- %2 = begin_access [read] [static] %0 : $*X      
- %3 = load [copy] %2 : $*X              
- end_access %2 : $*X              
- %5 = function_ref @useX : $@convention(thin) (@owned X) -> ()  
- %6 = apply %5(%3) : $@convention(thin) (@owned X) -> ()
- br bb1                        
-
-bb1:   
- br bb2   
-
-bb2:   
- cond_br undef, bb3, bb4   
-
-bb3:   
- br bb1   
-
-bb4:   
- destroy_addr %0 : $*X   
- cond_br undef, bb5, bb6   
-
-bb5:   
- %13 = begin_access [modify] [static] %0 : $*X  
- %14 = apply %1() : $@convention(thin) () -> @owned X 
- store %14 to [init] %13 : $*X            
- end_access %13 : $*X                 
- br bb7                        
-
-bb6:   
- %18 = begin_access [modify] [static] %0 : $*X  
- %19 = apply %1() : $@convention(thin) () -> @owned X 
- store %19 to [init] %18 : $*X            
- end_access %18 : $*X                 
- br bb7                        
-
-bb7:   
- %23 = tuple ()   
- return %23 : $()   
-}
-
-// CHECK-LABEL: sil [ossa] @$sSlsE20_failEarlyRangeCheck_6boundsy5IndexQz_SnyADGtFSnySiG_Tg5 : {{.*}} {
-// CHECK-LABEL: } // end sil function '$sSlsE20_failEarlyRangeCheck_6boundsy5IndexQz_SnyADGtFSnySiG_Tg5'
-sil [ossa] @$sSlsE20_failEarlyRangeCheck_6boundsy5IndexQz_SnyADGtFSnySiG_Tg5 : $@convention(method) (Int, Range<Int>, Range<Int>) -> () {
-bb0(%0 : $Int, %1 : $Range<Int>, %2 : $Range<Int>):
-  debug_value %0 : $Int, let, name "index", argno 1
-  %4 = alloc_stack $Int
-  store %0 to [trivial] %4 : $*Int
-  debug_value %1 : $Range<Int>, let, name "bounds", argno 2
-  %7 = alloc_stack $Range<Int>
-  store %1 to [trivial] %7 : $*Range<Int>
-  debug_value %2 : $Range<Int>, let, name "self", argno 3, implicit
-  %10 = alloc_stack $Range<Int>
-  store %2 to [trivial] %10 : $*Range<Int>
-  debug_value %4 : $*Int, let, name "index", argno 1, expr op_deref
-  debug_value %7 : $*Range<Int>, let, name "bounds", argno 2, expr op_deref
-  debug_value %10 : $*Range<Int>, let, name "self", argno 3, implicit, expr op_deref
-  %15 = alloc_stack $Range<Int>
-  copy_addr %7 to [init] %15 : $*Range<Int>
-  %17 = alloc_stack $Int
-  copy_addr %4 to [init] %17 : $*Int
-  %19 = string_literal utf8 "Index out of bounds"
-  %20 = integer_literal $Builtin.Word, 19
-  %21 = builtin "ptrtoint_Word"(%19 : $Builtin.RawPointer) : $Builtin.Word
-  br bb1
-
-bb1:
-  %23 = integer_literal $Builtin.Int8, 2
-  br bb2
-
-bb2:
-  %25 = struct $StaticString (%21 : $Builtin.Word, %20 : $Builtin.Word, %23 : $Builtin.Int8)
-  %26 = string_literal utf8 "Swift/Collection.swift"
-  %27 = integer_literal $Builtin.Word, 22
-  %28 = builtin "ptrtoint_Word"(%26 : $Builtin.RawPointer) : $Builtin.Word
-  br bb3
-
-bb3:
-  %30 = integer_literal $Builtin.Int8, 2
-  br bb4
-
-bb4:
-  %32 = struct $StaticString (%28 : $Builtin.Word, %27 : $Builtin.Word, %30 : $Builtin.Int8)
-  %33 = integer_literal $Builtin.Int64, 714
-  %34 = struct $UInt (%33 : $Builtin.Int64)
-  %35 = builtin "assert_configuration"() : $Builtin.Int32
-  %36 = integer_literal $Builtin.Int32, 0
-  %37 = builtin "cmp_eq_Int32"(%35 : $Builtin.Int32, %36 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %37, bb5, bb6
-
-bb5:
-  %39 = metatype $@thick Int.Type
-  %40 = struct_element_addr %15 : $*Range<Int>, #Range.lowerBound
-  %41 = alloc_stack $Int
-  copy_addr %40 to [init] %41 : $*Int
-  %43 = witness_method $Int, #Comparable."<=" : <Self where Self : Comparable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %44 = apply %43<Int>(%41, %17, %39) : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %41 : $*Int
-  dealloc_stack %41 : $*Int
-  %47 = alloc_stack $Int
-  copy_addr %17 to [init] %47 : $*Int
-  %49 = alloc_stack $Range<Int>
-  copy_addr %15 to [init] %49 : $*Range<Int>
-  %51 = struct_extract %44 : $Bool, #Bool._value
-  cond_br %51, bb7, bb8
-
-bb6:
-  %53 = builtin "assert_configuration"() : $Builtin.Int32
-  %54 = integer_literal $Builtin.Int32, 1
-  %55 = builtin "cmp_eq_Int32"(%53 : $Builtin.Int32, %54 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %55, bb18, bb19
-
-bb7:
-  %57 = metatype $@thick Int.Type
-  %58 = struct_element_addr %49 : $*Range<Int>, #Range.upperBound
-  %59 = alloc_stack $Int
-  copy_addr %58 to [init] %59 : $*Int
-  %61 = witness_method $Int, #Comparable."<" : <Self where Self : Comparable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %62 = apply %61<Int>(%47, %59, %57) : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %59 : $*Int
-  dealloc_stack %59 : $*Int
-  br bb9(%62 : $Bool)
-
-bb8:
-  %66 = integer_literal $Builtin.Int1, 0
-  %67 = struct $Bool (%66 : $Builtin.Int1)
-  br bb9(%67 : $Bool)
-
-bb9(%69 : $Bool):
-  destroy_addr %47 : $*Int
-  destroy_addr %49 : $*Range<Int>
-  dealloc_stack %49 : $*Range<Int>
-  dealloc_stack %47 : $*Int
-  %74 = struct_extract %69 : $Bool, #Bool._value
-  %75 = integer_literal $Builtin.Int1, -1
-  %76 = builtin "int_expect_Int1"(%74 : $Builtin.Int1, %75 : $Builtin.Int1) : $Builtin.Int1
-  %77 = integer_literal $Builtin.Int1, -1
-  %78 = builtin "xor_Int1"(%76 : $Builtin.Int1, %77 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %78, bb10, bb11
-
-bb10:
-  %80 = string_literal utf8 "Fatal error"
-  %81 = integer_literal $Builtin.Word, 11
-  %82 = builtin "ptrtoint_Word"(%80 : $Builtin.RawPointer) : $Builtin.Word
-  br bb12
-
-bb11:
-  destroy_addr %17 : $*Int
-  destroy_addr %15 : $*Range<Int>
-  br bb17
-
-bb12:
-  %87 = integer_literal $Builtin.Int8, 2
-  br bb13
-
-bb13:
-  %89 = struct $StaticString (%82 : $Builtin.Word, %81 : $Builtin.Word, %87 : $Builtin.Int8)
-  %90 = builtin "assert_configuration"() : $Builtin.Int32
-  %91 = integer_literal $Builtin.Int32, 0
-  %92 = builtin "cmp_eq_Int32"(%90 : $Builtin.Int32, %91 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %92, bb14, bb15
-
-bb14:
-  %94 = integer_literal $Builtin.Int32, 1
-  %95 = struct $UInt32 (%94 : $Builtin.Int32)
-  br bb16(%95 : $UInt32)
-
-bb15:
-  %97 = integer_literal $Builtin.Int32, 0
-  %98 = struct $UInt32 (%97 : $Builtin.Int32)
-  br bb16(%98 : $UInt32)
-
-bb16(%100 : $UInt32):
-  %101 = function_ref @$ss17_assertionFailure__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %102 = apply %101(%89, %25, %32, %34, %100) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb17:
-  %104 = tuple ()
-  dealloc_stack %17 : $*Int
-  dealloc_stack %15 : $*Range<Int>
-  %107 = tuple ()
-  dealloc_stack %10 : $*Range<Int>
-  dealloc_stack %7 : $*Range<Int>
-  dealloc_stack %4 : $*Int
-  return %107 : $()
-
-bb18:
-  %112 = metatype $@thick Int.Type
-  %113 = struct_element_addr %15 : $*Range<Int>, #Range.lowerBound
-  %114 = alloc_stack $Int
-  copy_addr %113 to [init] %114 : $*Int
-  %116 = witness_method $Int, #Comparable."<=" : <Self where Self : Comparable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %117 = apply %116<Int>(%114, %17, %112) : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %114 : $*Int
-  dealloc_stack %114 : $*Int
-  %120 = alloc_stack $Int
-  copy_addr [take] %17 to [init] %120 : $*Int
-  %122 = alloc_stack $Range<Int>
-  copy_addr [take] %15 to [init] %122 : $*Range<Int>
-  %124 = struct_extract %117 : $Bool, #Bool._value
-  cond_br %124, bb20, bb21
-
-bb19:
-  destroy_addr %17 : $*Int
-  destroy_addr %15 : $*Range<Int>
-  br bb23
-
-bb20:
-  %129 = metatype $@thick Int.Type
-  %130 = struct_element_addr %122 : $*Range<Int>, #Range.upperBound
-  %131 = alloc_stack $Int
-  copy_addr %130 to [init] %131 : $*Int
-  %133 = witness_method $Int, #Comparable."<" : <Self where Self : Comparable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %134 = apply %133<Int>(%120, %131, %129) : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %131 : $*Int
-  dealloc_stack %131 : $*Int
-  br bb22(%134 : $Bool)
-
-bb21:
-  %138 = integer_literal $Builtin.Int1, 0
-  %139 = struct $Bool (%138 : $Builtin.Int1)
-  br bb22(%139 : $Bool)
-
-bb22(%141 : $Bool):
-  destroy_addr %120 : $*Int
-  destroy_addr %122 : $*Range<Int>
-  dealloc_stack %122 : $*Range<Int>
-  dealloc_stack %120 : $*Int
-  %146 = struct_extract %141 : $Bool, #Bool._value
-  %147 = integer_literal $Builtin.Int1, -1
-  %148 = builtin "xor_Int1"(%146 : $Builtin.Int1, %147 : $Builtin.Int1) : $Builtin.Int1
-  cond_fail %148 : $Builtin.Int1, "Index out of bounds"
-  br bb23
-
-bb23:
-  br bb17
-}
-
-// CHECK-LABEL: sil [ossa] @$sSzsE12_description5radix9uppercaseSSSi_SbtFs4Int8V_Tg5 : {{.*}} {
-// CHECK-LABEL: } // end sil function '$sSzsE12_description5radix9uppercaseSSSi_SbtFs4Int8V_Tg5'
-sil [ossa] @$sSzsE12_description5radix9uppercaseSSSi_SbtFs4Int8V_Tg5 : $@convention(method) (Int, Bool, Int8) -> @owned String {
-bb0(%0 : $Int, %1 : $Bool, %2 : $Int8):
-  debug_value %2 : $Int8, let, name "self", argno 3, implicit
-  %4 = alloc_stack $Int8
-  store %2 to [trivial] %4 : $*Int8
-  debug_value %0 : $Int, let, name "radix", argno 1
-  debug_value %1 : $Bool, let, name "uppercase", argno 2
-  debug_value %4 : $*Int8, let, name "self", argno 3, implicit, expr op_deref
-  %9 = string_literal utf8 "Radix must be between 2 and 36"
-  %10 = integer_literal $Builtin.Word, 30
-  %11 = builtin "ptrtoint_Word"(%9 : $Builtin.RawPointer) : $Builtin.Word
-  br bb1
-
-bb1:
-  %13 = integer_literal $Builtin.Int8, 2
-  br bb2
-
-bb2:
-  %15 = struct $StaticString (%11 : $Builtin.Word, %10 : $Builtin.Word, %13 : $Builtin.Int8)
-  %16 = string_literal utf8 "Swift/Integers.swift"
-  %17 = integer_literal $Builtin.Word, 20
-  %18 = builtin "ptrtoint_Word"(%16 : $Builtin.RawPointer) : $Builtin.Word
-  br bb3
-
-bb3:
-  %20 = integer_literal $Builtin.Int8, 2
-  br bb4
-
-bb4:
-  %22 = struct $StaticString (%18 : $Builtin.Word, %17 : $Builtin.Word, %20 : $Builtin.Int8)
-  %23 = integer_literal $Builtin.Int64, 1498
-  %24 = struct $UInt (%23 : $Builtin.Int64)
-  %25 = builtin "assert_configuration"() : $Builtin.Int32
-  %26 = integer_literal $Builtin.Int32, 0
-  %27 = builtin "cmp_eq_Int32"(%25 : $Builtin.Int32, %26 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %27, bb5, bb6
-
-bb5:
-  %29 = metatype $@thin ClosedRange<Int>.Type
-  %30 = metatype $@thick ClosedRange<Int>.Type
-  %31 = alloc_stack $ClosedRange<Int>
-  %32 = metatype $@thin Int.Type
-  %33 = integer_literal $Builtin.Int64, 2
-  %34 = struct $Int (%33 : $Builtin.Int64)
-  %35 = integer_literal $Builtin.Int64, 36
-  %36 = struct $Int (%35 : $Builtin.Int64)
-  br bb7
-
-bb6:
-  %38 = builtin "assert_configuration"() : $Builtin.Int32
-  %39 = integer_literal $Builtin.Int32, 1
-  %40 = builtin "cmp_eq_Int32"(%38 : $Builtin.Int32, %39 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %40, bb60, bb61
-
-bb7:
-  br bb8
-
-bb8:
-  br bb9
-
-bb9:
-  br bb10
-
-bb10:
-  %45 = builtin "assert_configuration"() : $Builtin.Int32
-  %46 = integer_literal $Builtin.Int32, 0
-  %47 = builtin "cmp_eq_Int32"(%45 : $Builtin.Int32, %46 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %47, bb11, bb12
-
-bb11:
-  br bb13
-
-bb12:
-  %50 = builtin "assert_configuration"() : $Builtin.Int32
-  %51 = integer_literal $Builtin.Int32, 1
-  %52 = builtin "cmp_eq_Int32"(%50 : $Builtin.Int32, %51 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %52, bb57, bb58
-
-bb13:
-  br bb14
-
-bb14:
-  %55 = tuple ()
-  %56 = metatype $@thin ClosedRange<Int>.Type
-  %57 = alloc_stack $Int
-  store %34 to [trivial] %57 : $*Int
-  %59 = alloc_stack $Int
-  store %36 to [trivial] %59 : $*Int
-  %61 = function_ref @$sSN16_uncheckedBoundsSNyxGx5lower_x5uppert_tcfC : $@convention(method) <τ_0_0 where τ_0_0 : Comparable> (@in τ_0_0, @in τ_0_0, @thin ClosedRange<τ_0_0>.Type) -> @out ClosedRange<τ_0_0>
-  %62 = apply %61<Int>(%31, %57, %59, %56) : $@convention(method) <τ_0_0 where τ_0_0 : Comparable> (@in τ_0_0, @in τ_0_0, @thin ClosedRange<τ_0_0>.Type) -> @out ClosedRange<τ_0_0>
-  dealloc_stack %59 : $*Int
-  dealloc_stack %57 : $*Int
-  %65 = tuple ()
-  %66 = load [trivial] %31 : $*ClosedRange<Int>
-  %67 = alloc_stack $ClosedRange<Int>
-  store %66 to [trivial] %67 : $*ClosedRange<Int>
-  %69 = alloc_stack $Int
-  store %0 to [trivial] %69 : $*Int
-  %71 = function_ref @$sSXsE2teoiySbx_5BoundQztFZ : $@convention(method) <τ_0_0 where τ_0_0 : RangeExpression> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0.Bound, @thick τ_0_0.Type) -> Bool
-  %72 = apply %71<ClosedRange<Int>>(%67, %69, %30) : $@convention(method) <τ_0_0 where τ_0_0 : RangeExpression> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0.Bound, @thick τ_0_0.Type) -> Bool
-  dealloc_stack %69 : $*Int
-  dealloc_stack %67 : $*ClosedRange<Int>
-  dealloc_stack %31 : $*ClosedRange<Int>
-  %76 = struct_extract %72 : $Bool, #Bool._value
-  %77 = integer_literal $Builtin.Int1, -1
-  %78 = builtin "int_expect_Int1"(%76 : $Builtin.Int1, %77 : $Builtin.Int1) : $Builtin.Int1
-  %79 = integer_literal $Builtin.Int1, -1
-  %80 = builtin "xor_Int1"(%78 : $Builtin.Int1, %79 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %80, bb15, bb16
-
-bb15:
-  %82 = string_literal utf8 "Fatal error"
-  %83 = integer_literal $Builtin.Word, 11
-  %84 = builtin "ptrtoint_Word"(%82 : $Builtin.RawPointer) : $Builtin.Word
-  br bb17
-
-bb16:
-  br bb22
-
-bb17:
-  %87 = integer_literal $Builtin.Int8, 2
-  br bb18
-
-bb18:
-  %89 = struct $StaticString (%84 : $Builtin.Word, %83 : $Builtin.Word, %87 : $Builtin.Int8)
-  %90 = builtin "assert_configuration"() : $Builtin.Int32
-  %91 = integer_literal $Builtin.Int32, 0
-  %92 = builtin "cmp_eq_Int32"(%90 : $Builtin.Int32, %91 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %92, bb19, bb20
-
-bb19:
-  %94 = integer_literal $Builtin.Int32, 1
-  %95 = struct $UInt32 (%94 : $Builtin.Int32)
-  br bb21(%95 : $UInt32)
-
-bb20:
-  %97 = integer_literal $Builtin.Int32, 0
-  %98 = struct $UInt32 (%97 : $Builtin.Int32)
-  br bb21(%98 : $UInt32)
-
-bb21(%100 : $UInt32):
-  %101 = function_ref @$ss17_assertionFailure__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %102 = apply %101(%89, %15, %22, %24, %100) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb22:
-  %104 = tuple ()
-  %105 = witness_method $Int8, #BinaryInteger.bitWidth!getter : <Self where Self : BinaryInteger> (Self) -> () -> Int : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %106 = apply %105<Int8>(%4) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %107 = integer_literal $Builtin.Int64, 64
-  %108 = struct_extract %106 : $Int, #Int._value
-  %109 = builtin "cmp_slt_Int64"(%107 : $Builtin.Int64, %108 : $Builtin.Int64) : $Builtin.Int1
-  %110 = integer_literal $Builtin.Int1, -1
-  %111 = builtin "xor_Int1"(%109 : $Builtin.Int1, %110 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %111, bb23, bb24
-
-bb23:
-  %113 = alloc_stack $Int64
-  %114 = metatype $@thin Int64.Type
-  %115 = metatype $@thick Int64.Type
-  %116 = alloc_stack $Int
-  store %0 to [trivial] %116 : $*Int
-  %118 = function_ref @$sSZss17FixedWidthIntegerRzrlEyxqd__cSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger, τ_0_0 : SignedInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %119 = apply %118<Int64, Int>(%113, %116, %115) : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger, τ_0_0 : SignedInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %116 : $*Int
-  %121 = load [trivial] %113 : $*Int64
-  debug_value %121 : $Int64, let, name "radix_"
-  dealloc_stack %113 : $*Int64
-  %124 = metatype $@thick Int8.Type
-  %125 = witness_method $Int8, #BinaryInteger.isSigned!getter : <Self where Self : BinaryInteger> (Self.Type) -> () -> Bool : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %126 = apply %125<Int8>(%124) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %127 = struct_extract %126 : $Bool, #Bool._value
-  cond_br %127, bb25, bb26
-
-bb24:
-  %129 = metatype $@thick Int8.Type
-  %130 = integer_literal $Builtin.IntLiteral, 0
-  %131 = metatype $@thick Int8.Type
-  %132 = alloc_stack $Int8
-  %133 = witness_method $Int8, #_ExpressibleByBuiltinIntegerLiteral.init!allocator : <Self where Self : _ExpressibleByBuiltinIntegerLiteral> (Self.Type) -> (Builtin.IntLiteral) -> Self : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %134 = apply %133<Int8>(%132, %130, %131) : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %135 = metatype $@thick Int8.Type
-  %136 = alloc_stack $Int8
-  %137 = witness_method $Int8, #ExpressibleByIntegerLiteral.init!allocator : <Self where Self : ExpressibleByIntegerLiteral> (Self.Type) -> (Self.IntegerLiteralType) -> Self : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %138 = apply %137<Int8>(%136, %132, %135) : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %139 = witness_method $Int8, #Equatable."==" : <Self where Self : Equatable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %140 = apply %139<Int8>(%4, %136, %129) : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %136 : $*Int8
-  dealloc_stack %136 : $*Int8
-  dealloc_stack %132 : $*Int8
-  %144 = struct_extract %140 : $Bool, #Bool._value
-  cond_br %144, bb29, bb30
-
-bb25:
-  %146 = alloc_stack $Int64
-  %147 = metatype $@thin Int64.Type
-  %148 = metatype $@thick Int64.Type
-  %149 = alloc_stack $Int8
-  copy_addr %4 to [init] %149 : $*Int8
-  %151 = function_ref @$ss17FixedWidthIntegerPsE18truncatingIfNeededxqd___tcSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %152 = apply %151<Int64, Int8>(%146, %149, %148) : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %149 : $*Int8
-  %154 = load [trivial] %146 : $*Int64
-  %155 = function_ref @$ss14_int64ToString_5radix9uppercaseSSs5Int64V_AESbtF : $@convention(thin) (Int64, Int64, Bool) -> @owned String
-  %156 = apply %155(%154, %121, %1) : $@convention(thin) (Int64, Int64, Bool) -> @owned String
-  dealloc_stack %146 : $*Int64
-  br bb27(%156 : $String)
-
-bb26:
-  %159 = alloc_stack $UInt64
-  %160 = metatype $@thin UInt64.Type
-  %161 = metatype $@thick UInt64.Type
-  %162 = alloc_stack $Int8
-  copy_addr %4 to [init] %162 : $*Int8
-  %164 = function_ref @$ss17FixedWidthIntegerPsE18truncatingIfNeededxqd___tcSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %165 = apply %164<UInt64, Int8>(%159, %162, %161) : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %162 : $*Int8
-  %167 = load [trivial] %159 : $*UInt64
-  %168 = function_ref @$ss15_uint64ToString_5radix9uppercaseSSs6UInt64V_s5Int64VSbtF : $@convention(thin) (UInt64, Int64, Bool) -> @owned String
-  %169 = apply %168(%167, %121, %1) : $@convention(thin) (UInt64, Int64, Bool) -> @owned String
-  dealloc_stack %159 : $*UInt64
-  br bb27(%169 : $String)
-
-bb27(%172 : @owned $String):
-  br bb28(%172 : $String)
-
-bb28(%174 : @owned $String):
-  dealloc_stack %4 : $*Int8
-  return %174 : $String
-
-bb29:
-  %177 = string_literal utf8 "0"
-  %178 = integer_literal $Builtin.Word, 1
-  %179 = integer_literal $Builtin.Int1, -1
-  %180 = metatype $@thin String.Type
-  %181 = function_ref @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
-  %182 = apply %181(%177, %178, %179, %180) : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
-  br bb28(%182 : $String)
-
-bb30:
-  %184 = struct_extract %0 : $Int, #Int._value
-  %185 = builtin "int_ctpop_Int64"(%184 : $Builtin.Int64) : $Builtin.Int64
-  %186 = integer_literal $Builtin.Int64, 1
-  %187 = builtin "cmp_eq_Int64"(%185 : $Builtin.Int64, %186 : $Builtin.Int64) : $Builtin.Int1
-  %188 = struct $Bool (%187 : $Builtin.Int1)
-  debug_value %188 : $Bool, let, name "isRadixPowerOfTwo"
-  %190 = alloc_stack $UInt8, let, name "radix_"
-  %191 = metatype $@thick UInt8.Type
-  %192 = alloc_stack $Int
-  store %0 to [trivial] %192 : $*Int
-  %194 = witness_method $UInt8, #BinaryInteger.init!allocator : <Self where Self : BinaryInteger><T where T : BinaryInteger> (Self.Type) -> (T) -> Self : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %195 = apply %194<UInt8, Int>(%190, %192, %191) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %192 : $*Int
-  %197 = integer_literal $Builtin.Int64, 10
-  %198 = struct_extract %0 : $Int, #Int._value
-  %199 = builtin "cmp_slt_Int64"(%197 : $Builtin.Int64, %198 : $Builtin.Int64) : $Builtin.Int1
-  %200 = struct $Bool (%199 : $Builtin.Int1)
-  debug_value %200 : $Bool, let, name "hasLetters"
-  %202 = metatype $@thick Int8.Type
-  %203 = witness_method $Int8, #BinaryInteger.isSigned!getter : <Self where Self : BinaryInteger> (Self.Type) -> () -> Bool : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %204 = apply %203<Int8>(%202) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %205 = alloc_stack $Int8
-  copy_addr %4 to [init] %205 : $*Int8
-  %207 = struct_extract %204 : $Bool, #Bool._value
-  cond_br %207, bb31, bb32
-
-bb31:
-  %209 = metatype $@thick Int8.Type
-  %210 = integer_literal $Builtin.IntLiteral, 0
-  %211 = metatype $@thick Int8.Type
-  %212 = alloc_stack $Int8
-  %213 = witness_method $Int8, #_ExpressibleByBuiltinIntegerLiteral.init!allocator : <Self where Self : _ExpressibleByBuiltinIntegerLiteral> (Self.Type) -> (Builtin.IntLiteral) -> Self : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %214 = apply %213<Int8>(%212, %210, %211) : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %215 = metatype $@thick Int8.Type
-  %216 = alloc_stack $Int8
-  %217 = witness_method $Int8, #ExpressibleByIntegerLiteral.init!allocator : <Self where Self : ExpressibleByIntegerLiteral> (Self.Type) -> (Self.IntegerLiteralType) -> Self : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %218 = apply %217<Int8>(%216, %212, %215) : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %219 = witness_method $Int8, #Comparable."<" : <Self where Self : Comparable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %220 = apply %219<Int8>(%205, %216, %209) : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %216 : $*Int8
-  destroy_addr %205 : $*Int8
-  dealloc_stack %216 : $*Int8
-  dealloc_stack %212 : $*Int8
-  br bb33(%220 : $Bool)
-
-bb32:
-  destroy_addr %205 : $*Int8
-  %227 = integer_literal $Builtin.Int1, 0
-  %228 = struct $Bool (%227 : $Builtin.Int1)
-  br bb33(%228 : $Bool)
-
-bb33(%230 : $Bool):
-  dealloc_stack %205 : $*Int8
-  debug_value %230 : $Bool, let, name "isNegative"
-  %233 = alloc_stack $UInt8, var, name "value"
-  %234 = witness_method $Int8, #Numeric.magnitude!getter : <Self where Self : Numeric> (Self) -> () -> Self.Magnitude : $@convention(witness_method: Numeric) <τ_0_0 where τ_0_0 : Numeric> (@in_guaranteed τ_0_0) -> @out τ_0_0.Magnitude
-  %235 = apply %234<Int8>(%233, %4) : $@convention(witness_method: Numeric) <τ_0_0 where τ_0_0 : Numeric> (@in_guaranteed τ_0_0) -> @out τ_0_0.Magnitude
-  %236 = alloc_stack $Array<UInt8>, var, name "result"
-  %237 = integer_literal $Builtin.Word, 0
-  %238 = function_ref @$ss27_allocateUninitializedArrayySayxG_BptBwlF : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
-  %239 = apply %238<UInt8>(%237) : $@convention(thin) <τ_0_0> (Builtin.Word) -> (@owned Array<τ_0_0>, Builtin.RawPointer)
-  (%240, %241) = destructure_tuple %239 : $(Array<UInt8>, Builtin.RawPointer)
-  %242 = pointer_to_address %241 : $Builtin.RawPointer to [strict] $*UInt8
-  store %240 to [init] %236 : $*Array<UInt8>
-  br bb34
-
-bb34:
-  %245 = alloc_stack $UInt8
-  copy_addr %233 to [init] %245 : $*UInt8
-  %247 = integer_literal $Builtin.Int64, 0
-  %248 = struct $Int (%247 : $Builtin.Int64)
-  %249 = metatype $@thick UInt8.Type
-  %250 = witness_method $UInt8, #BinaryInteger.isSigned!getter : <Self where Self : BinaryInteger> (Self.Type) -> () -> Bool : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %251 = apply %250<UInt8>(%249) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %252 = alloc_stack $UInt8
-  copy_addr %245 to [init] %252 : $*UInt8
-  %254 = struct_extract %251 : $Bool, #Bool._value
-  cond_br %254, bb35, bb36
-
-bb35:
-  %256 = metatype $@thick UInt8.Type
-  %257 = integer_literal $Builtin.IntLiteral, 0
-  %258 = metatype $@thick UInt8.Type
-  %259 = alloc_stack $UInt8
-  %260 = witness_method $UInt8, #_ExpressibleByBuiltinIntegerLiteral.init!allocator : <Self where Self : _ExpressibleByBuiltinIntegerLiteral> (Self.Type) -> (Builtin.IntLiteral) -> Self : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %261 = apply %260<UInt8>(%259, %257, %258) : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %262 = metatype $@thick UInt8.Type
-  %263 = alloc_stack $UInt8
-  %264 = witness_method $UInt8, #ExpressibleByIntegerLiteral.init!allocator : <Self where Self : ExpressibleByIntegerLiteral> (Self.Type) -> (Self.IntegerLiteralType) -> Self : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %265 = apply %264<UInt8>(%263, %259, %262) : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %266 = witness_method $UInt8, #Comparable."<" : <Self where Self : Comparable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %267 = apply %266<UInt8>(%252, %263, %256) : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %263 : $*UInt8
-  dealloc_stack %263 : $*UInt8
-  dealloc_stack %259 : $*UInt8
-  br bb37(%267 : $Bool)
-
-bb36:
-  %272 = integer_literal $Builtin.Int1, 0
-  %273 = struct $Bool (%272 : $Builtin.Int1)
-  br bb37(%273 : $Bool)
-
-bb37(%275 : $Bool):
-  destroy_addr %252 : $*UInt8
-  dealloc_stack %252 : $*UInt8
-  %278 = metatype $@thick Int.Type
-  %279 = function_ref @$sSZsE8isSignedSbvgZ : $@convention(method) <τ_0_0 where τ_0_0 : SignedInteger> (@thick τ_0_0.Type) -> Bool
-  %280 = apply %279<Int>(%278) : $@convention(method) <τ_0_0 where τ_0_0 : SignedInteger> (@thick τ_0_0.Type) -> Bool
-  %281 = struct_extract %280 : $Bool, #Bool._value
-  cond_br %281, bb38, bb39
-
-bb38:
-  %283 = tuple ()
-  %284 = tuple ()
-  %285 = tuple ()
-  %286 = integer_literal $Builtin.Int1, 0
-  %287 = struct $Bool (%286 : $Builtin.Int1)
-  br bb40(%287 : $Bool)
-
-bb39:
-  %289 = integer_literal $Builtin.Int1, 0
-  %290 = struct $Bool (%289 : $Builtin.Int1)
-  br bb40(%290 : $Bool)
-
-bb40(%292 : $Bool):
-  %293 = metatype $@thin Bool.Type
-  %294 = struct_extract %275 : $Bool, #Bool._value
-  %295 = struct_extract %292 : $Bool, #Bool._value
-  %296 = builtin "cmp_eq_Int1"(%294 : $Builtin.Int1, %295 : $Builtin.Int1) : $Builtin.Int1
-  %297 = integer_literal $Builtin.Int1, -1
-  %298 = builtin "xor_Int1"(%296 : $Builtin.Int1, %297 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %298, bb41, bb42
-
-bb41:
-  %300 = integer_literal $Builtin.Int1, 0
-  %301 = struct $Bool (%300 : $Builtin.Int1)
-  br bb43(%301 : $Bool)
-
-bb42:
-  %303 = witness_method $UInt8, #BinaryInteger.bitWidth!getter : <Self where Self : BinaryInteger> (Self) -> () -> Int : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %304 = apply %303<UInt8>(%245) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %305 = alloc_stack $Int
-  store %248 to [trivial] %305 : $*Int
-  %307 = function_ref @$ss17FixedWidthIntegerPsE03bitB0Sivg : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger> (@in_guaranteed τ_0_0) -> Int
-  %308 = apply %307<Int>(%305) : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger> (@in_guaranteed τ_0_0) -> Int
-  destroy_addr %305 : $*Int
-  %310 = struct_extract %304 : $Int, #Int._value
-  %311 = struct_extract %308 : $Int, #Int._value
-  %312 = builtin "cmp_slt_Int64"(%310 : $Builtin.Int64, %311 : $Builtin.Int64) : $Builtin.Int1
-  dealloc_stack %305 : $*Int
-  cond_br %312, bb51, bb52
-
-bb43(%315 : $Bool):
-  %316 = struct_extract %315 : $Bool, #Bool._value
-  %317 = integer_literal $Builtin.Int1, -1
-  %318 = builtin "xor_Int1"(%316 : $Builtin.Int1, %317 : $Builtin.Int1) : $Builtin.Int1
-  destroy_addr %245 : $*UInt8
-  dealloc_stack %245 : $*UInt8
-  cond_br %318, bb44, bb45
-
-bb44:
-  %322 = alloc_stack $UInt8, let, name "quotient"
-  %323 = alloc_stack $UInt8, let, name "remainder"
-  %324 = alloc_stack $UInt8
-  copy_addr %233 to [init] %324 : $*UInt8
-  %326 = function_ref @$sSzsE12_description5radix9uppercaseSSSi_SbtF21_quotientAndRemainderL_y9MagnitudeQz_AFtAFSzRzlF : $@convention(thin) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0.Magnitude, Bool, Int, @in_guaranteed τ_0_0.Magnitude) -> (@out τ_0_0.Magnitude, @out τ_0_0.Magnitude)
-  %327 = apply %326<Int8>(%322, %323, %324, %188, %0, %190) : $@convention(thin) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0.Magnitude, Bool, Int, @in_guaranteed τ_0_0.Magnitude) -> (@out τ_0_0.Magnitude, @out τ_0_0.Magnitude)
-  destroy_addr %324 : $*UInt8
-  dealloc_stack %324 : $*UInt8
-  %330 = alloc_stack $UInt8
-  %331 = metatype $@thin UInt8.Type
-  %332 = metatype $@thick UInt8.Type
-  %333 = alloc_stack $UInt8
-  copy_addr %323 to [init] %333 : $*UInt8
-  %335 = function_ref @$ss17FixedWidthIntegerPsE18truncatingIfNeededxqd___tcSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %336 = apply %335<UInt8, UInt8>(%330, %333, %332) : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %333 : $*UInt8
-  %338 = load [trivial] %330 : $*UInt8
-  %339 = function_ref @$sSzsE12_description5radix9uppercaseSSSi_SbtF6_asciiL_ys5UInt8VAFSzRzlF : $@convention(thin) (UInt8, Bool, Bool) -> UInt8
-  %340 = apply %339(%338, %200, %1) : $@convention(thin) (UInt8, Bool, Bool) -> UInt8
-  dealloc_stack %330 : $*UInt8
-  %342 = alloc_stack $UInt8
-  store %340 to [trivial] %342 : $*UInt8
-  %344 = function_ref @$sSa6appendyyxnF : $@convention(method) <τ_0_0> (@in τ_0_0, @inout Array<τ_0_0>) -> ()
-  %345 = apply %344<UInt8>(%342, %236) : $@convention(method) <τ_0_0> (@in τ_0_0, @inout Array<τ_0_0>) -> ()
-  dealloc_stack %342 : $*UInt8
-  destroy_addr %233 : $*UInt8
-  copy_addr %322 to [init] %233 : $*UInt8
-  destroy_addr %323 : $*UInt8
-  dealloc_stack %323 : $*UInt8
-  destroy_addr %322 : $*UInt8
-  dealloc_stack %322 : $*UInt8
-  br bb34
-
-bb45:
-  %354 = struct_extract %230 : $Bool, #Bool._value
-  cond_br %354, bb46, bb47
-
-bb46:
-  %356 = alloc_stack $UInt8
-  %357 = metatype $@thin UInt8.Type
-  %358 = metatype $@thick UInt8.Type
-  %359 = integer_literal $Builtin.Int32, 45
-  %360 = struct $UInt32 (%359 : $Builtin.Int32)
-  %361 = struct $Unicode.Scalar (%360 : $UInt32)
-  %362 = function_ref @$ss7UnicodeO6ScalarV5values6UInt32Vvg : $@convention(method) (Unicode.Scalar) -> UInt32
-  %363 = apply %362(%361) : $@convention(method) (Unicode.Scalar) -> UInt32
-  %364 = alloc_stack $UInt32
-  store %363 to [trivial] %364 : $*UInt32
-  %366 = function_ref @$sSUss17FixedWidthIntegerRzrlEyxqd__cSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger, τ_0_0 : UnsignedInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %367 = apply %366<UInt8, UInt32>(%356, %364, %358) : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger, τ_0_0 : UnsignedInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %364 : $*UInt32
-  %369 = load [trivial] %356 : $*UInt8
-  %370 = alloc_stack $UInt8
-  store %369 to [trivial] %370 : $*UInt8
-  %372 = function_ref @$sSa6appendyyxnF : $@convention(method) <τ_0_0> (@in τ_0_0, @inout Array<τ_0_0>) -> ()
-  %373 = apply %372<UInt8>(%370, %236) : $@convention(method) <τ_0_0> (@in τ_0_0, @inout Array<τ_0_0>) -> ()
-  dealloc_stack %370 : $*UInt8
-  dealloc_stack %356 : $*UInt8
-  br bb48
-
-bb47:
-  br bb48
-
-bb48:
-  %378 = function_ref @$sSMsSKRzrlE7reverseyyF : $@convention(method) <τ_0_0 where τ_0_0 : BidirectionalCollection, τ_0_0 : MutableCollection> (@inout τ_0_0) -> ()
-  %379 = apply %378<Array<UInt8>>(%236) : $@convention(method) <τ_0_0 where τ_0_0 : BidirectionalCollection, τ_0_0 : MutableCollection> (@inout τ_0_0) -> ()
-  %380 = alloc_stack $String
-  %381 = load [copy] %236 : $*Array<UInt8>
-  %382 = function_ref @$sSzsE12_description5radix9uppercaseSSSi_SbtFSSSRys5UInt8VGXEfU_ : $@convention(thin) (UnsafeBufferPointer<UInt8>) -> @owned String
-  %383 = thin_to_thick_function %382 : $@convention(thin) (UnsafeBufferPointer<UInt8>) -> @owned String to $@noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> @owned String
-  %384 = convert_function %383 : $@noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> @owned String to $@noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> (@owned String, @error Error)
-  %385 = function_ref @$sSRys5UInt8VGSSs5Error_pIgyozo_ACSSsAD_pIegyrzo_TR : $@convention(thin) (UnsafeBufferPointer<UInt8>, @noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> (@owned String, @error Error)) -> (@out String, @error Error)
-  %386 = partial_apply [callee_guaranteed] [on_stack] %385(%384) : $@convention(thin) (UnsafeBufferPointer<UInt8>, @noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> (@owned String, @error Error)) -> (@out String, @error Error)
-  %387 = convert_function %386 : $@noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> (@out String, @error Error) to $@noescape @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0 == τ_0_1> (UnsafeBufferPointer<τ_0_0>) -> (@out τ_0_2, @error Error) for <UInt8, UInt8, String>
-  %388 = function_ref @$sSa23withUnsafeBufferPointeryqd__qd__SRyxGKXEKlF : $@convention(method) <τ_0_0><τ_1_0> (@noescape @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0 == τ_0_1> (UnsafeBufferPointer<τ_0_0>) -> (@out τ_0_2, @error Error) for <τ_0_0, τ_0_0, τ_1_0>, @guaranteed Array<τ_0_0>) -> (@out τ_1_0, @error Error)
-  try_apply %388<UInt8, String>(%380, %387, %381) : $@convention(method) <τ_0_0><τ_1_0> (@noescape @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0 == τ_0_1> (UnsafeBufferPointer<τ_0_0>) -> (@out τ_0_2, @error Error) for <τ_0_0, τ_0_0, τ_1_0>, @guaranteed Array<τ_0_0>) -> (@out τ_1_0, @error Error), normal bb49, error bb50
-
-bb49(%390 : $()):
-  destroy_addr %190 : $*UInt8
-  dealloc_stack %386 : $@noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> (@out String, @error Error)
-  destroy_value %381 : $Array<UInt8>
-  %394 = load [take] %380 : $*String
-  dealloc_stack %380 : $*String
-  destroy_addr %236 : $*Array<UInt8>
-  dealloc_stack %236 : $*Array<UInt8>
-  destroy_addr %233 : $*UInt8
-  dealloc_stack %233 : $*UInt8
-  dealloc_stack %190 : $*UInt8
-  br bb28(%394 : $String)
-
-bb50(%402 : @owned $Error):
-  unreachable
-
-bb51:
-  %404 = alloc_stack $Int
-  %405 = metatype $@thick Int.Type
-  %406 = alloc_stack $UInt8
-  copy_addr %245 to [init] %406 : $*UInt8
-  %408 = function_ref @$ss17FixedWidthIntegerPsE18truncatingIfNeededxqd___tcSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %409 = apply %408<Int, UInt8>(%404, %406, %405) : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %410 = tuple ()
-  dealloc_stack %406 : $*UInt8
-  %412 = load [trivial] %404 : $*Int
-  %413 = struct_extract %412 : $Int, #Int._value
-  %414 = builtin "cmp_eq_Int64"(%413 : $Builtin.Int64, %247 : $Builtin.Int64) : $Builtin.Int1
-  %415 = struct $Bool (%414 : $Builtin.Int1)
-  destroy_addr %404 : $*Int
-  dealloc_stack %404 : $*Int
-  br bb43(%415 : $Bool)
-
-bb52:
-  %419 = witness_method $UInt8, #BinaryInteger.bitWidth!getter : <Self where Self : BinaryInteger> (Self) -> () -> Int : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %420 = apply %419<UInt8>(%245) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %421 = alloc_stack $Int
-  store %248 to [trivial] %421 : $*Int
-  %423 = function_ref @$ss17FixedWidthIntegerPsE03bitB0Sivg : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger> (@in_guaranteed τ_0_0) -> Int
-  %424 = apply %423<Int>(%421) : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger> (@in_guaranteed τ_0_0) -> Int
-  destroy_addr %421 : $*Int
-  %426 = struct_extract %424 : $Int, #Int._value
-  %427 = struct_extract %420 : $Int, #Int._value
-  %428 = builtin "cmp_slt_Int64"(%426 : $Builtin.Int64, %427 : $Builtin.Int64) : $Builtin.Int1
-  dealloc_stack %421 : $*Int
-  cond_br %428, bb53, bb54
-
-bb53:
-  %431 = metatype $@thick UInt8.Type
-  %432 = alloc_stack $UInt8
-  %433 = metatype $@thick UInt8.Type
-  %434 = alloc_stack $Int
-  store %248 to [trivial] %434 : $*Int
-  %436 = witness_method $UInt8, #BinaryInteger.init!allocator : <Self where Self : BinaryInteger><T where T : BinaryInteger> (Self.Type) -> (T) -> Self : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %437 = apply %436<UInt8, Int>(%432, %434, %433) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %434 : $*Int
-  %439 = witness_method $UInt8, #Equatable."==" : <Self where Self : Equatable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %440 = apply %439<UInt8>(%245, %432, %431) : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %432 : $*UInt8
-  dealloc_stack %432 : $*UInt8
-  br bb43(%440 : $Bool)
-
-bb54:
-  %444 = metatype $@thick UInt8.Type
-  %445 = witness_method $UInt8, #BinaryInteger.isSigned!getter : <Self where Self : BinaryInteger> (Self.Type) -> () -> Bool : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %446 = apply %445<UInt8>(%444) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %447 = struct_extract %446 : $Bool, #Bool._value
-  cond_br %447, bb55, bb56
-
-bb55:
-  %449 = alloc_stack $Int
-  %450 = metatype $@thick Int.Type
-  %451 = alloc_stack $UInt8
-  copy_addr %245 to [init] %451 : $*UInt8
-  %453 = function_ref @$ss17FixedWidthIntegerPsE18truncatingIfNeededxqd___tcSzRd__lufC : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %454 = apply %453<Int, UInt8>(%449, %451, %450) : $@convention(method) <τ_0_0 where τ_0_0 : FixedWidthInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %455 = tuple ()
-  dealloc_stack %451 : $*UInt8
-  %457 = load [trivial] %449 : $*Int
-  %458 = struct_extract %457 : $Int, #Int._value
-  %459 = builtin "cmp_eq_Int64"(%458 : $Builtin.Int64, %247 : $Builtin.Int64) : $Builtin.Int1
-  %460 = struct $Bool (%459 : $Builtin.Int1)
-  destroy_addr %449 : $*Int
-  dealloc_stack %449 : $*Int
-  br bb43(%460 : $Bool)
-
-bb56:
-  %464 = metatype $@thick UInt8.Type
-  %465 = alloc_stack $UInt8
-  %466 = metatype $@thick UInt8.Type
-  %467 = alloc_stack $Int
-  store %248 to [trivial] %467 : $*Int
-  %469 = witness_method $UInt8, #BinaryInteger.init!allocator : <Self where Self : BinaryInteger><T where T : BinaryInteger> (Self.Type) -> (T) -> Self : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %470 = apply %469<UInt8, Int>(%465, %467, %466) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %467 : $*Int
-  %472 = witness_method $UInt8, #Equatable."==" : <Self where Self : Equatable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %473 = apply %472<UInt8>(%245, %465, %464) : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %465 : $*UInt8
-  dealloc_stack %465 : $*UInt8
-  br bb43(%473 : $Bool)
-
-bb57:
-  br bb59
-
-bb58:
-  br bb59
-
-bb59:
-  br bb14
-
-bb60:
-  %480 = metatype $@thin ClosedRange<Int>.Type
-  %481 = metatype $@thick ClosedRange<Int>.Type
-  %482 = alloc_stack $ClosedRange<Int>
-  %483 = metatype $@thin Int.Type
-  %484 = integer_literal $Builtin.Int64, 2
-  %485 = struct $Int (%484 : $Builtin.Int64)
-  %486 = integer_literal $Builtin.Int64, 36
-  %487 = struct $Int (%486 : $Builtin.Int64)
-  br bb62
-
-bb61:
-  br bb70
-
-bb62:
-  br bb63
-
-bb63:
-  br bb64
-
-bb64:
-  br bb65
-
-bb65:
-  %493 = builtin "assert_configuration"() : $Builtin.Int32
-  %494 = integer_literal $Builtin.Int32, 0
-  %495 = builtin "cmp_eq_Int32"(%493 : $Builtin.Int32, %494 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %495, bb66, bb67
-
-bb66:
-  br bb68
-
-bb67:
-  %498 = builtin "assert_configuration"() : $Builtin.Int32
-  %499 = integer_literal $Builtin.Int32, 1
-  %500 = builtin "cmp_eq_Int32"(%498 : $Builtin.Int32, %499 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %500, bb71, bb72
-
-bb68:
-  br bb69
-
-bb69:
-  %503 = tuple ()
-  %504 = metatype $@thin ClosedRange<Int>.Type
-  %505 = alloc_stack $Int
-  store %485 to [trivial] %505 : $*Int
-  %507 = alloc_stack $Int
-  store %487 to [trivial] %507 : $*Int
-  %509 = function_ref @$sSN16_uncheckedBoundsSNyxGx5lower_x5uppert_tcfC : $@convention(method) <τ_0_0 where τ_0_0 : Comparable> (@in τ_0_0, @in τ_0_0, @thin ClosedRange<τ_0_0>.Type) -> @out ClosedRange<τ_0_0>
-  %510 = apply %509<Int>(%482, %505, %507, %504) : $@convention(method) <τ_0_0 where τ_0_0 : Comparable> (@in τ_0_0, @in τ_0_0, @thin ClosedRange<τ_0_0>.Type) -> @out ClosedRange<τ_0_0>
-  dealloc_stack %507 : $*Int
-  dealloc_stack %505 : $*Int
-  %513 = tuple ()
-  %514 = load [trivial] %482 : $*ClosedRange<Int>
-  %515 = alloc_stack $ClosedRange<Int>
-  store %514 to [trivial] %515 : $*ClosedRange<Int>
-  %517 = alloc_stack $Int
-  store %0 to [trivial] %517 : $*Int
-  %519 = function_ref @$sSXsE2teoiySbx_5BoundQztFZ : $@convention(method) <τ_0_0 where τ_0_0 : RangeExpression> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0.Bound, @thick τ_0_0.Type) -> Bool
-  %520 = apply %519<ClosedRange<Int>>(%515, %517, %481) : $@convention(method) <τ_0_0 where τ_0_0 : RangeExpression> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0.Bound, @thick τ_0_0.Type) -> Bool
-  dealloc_stack %517 : $*Int
-  dealloc_stack %515 : $*ClosedRange<Int>
-  dealloc_stack %482 : $*ClosedRange<Int>
-  %524 = struct_extract %520 : $Bool, #Bool._value
-  %525 = integer_literal $Builtin.Int1, -1
-  %526 = builtin "xor_Int1"(%524 : $Builtin.Int1, %525 : $Builtin.Int1) : $Builtin.Int1
-  cond_fail %526 : $Builtin.Int1, "Radix must be between 2 and 36"
-  br bb70
-
-bb70:
-  br bb22
-
-bb71:
-  br bb73
-
-bb72:
-  br bb73
-
-bb73:
-  br bb69
-}
-
-// CHECK-LABEL: sil [ossa] @$sSS_5radix9uppercaseSSx_SiSbtcSzRzlufC : {{.*}} {
-// CHECK-LABEL: } // end sil function '$sSS_5radix9uppercaseSSx_SiSbtcSzRzlufC'
-sil [ossa] @$sSS_5radix9uppercaseSSx_SiSbtcSzRzlufC : $@convention(method) <T where T : BinaryInteger> (@in T, Int, Bool, @thin String.Type) -> @owned String {
-bb0(%0 : $*T, %1 : $Int, %2 : $Bool, %3 : $@thin String.Type):
-  %10 = string_literal utf8 "Radix must be between 2 and 36"
-  %11 = integer_literal $Builtin.Word, 30
-  %12 = builtin "ptrtoint_Word"(%10 : $Builtin.RawPointer) : $Builtin.Word
-  %13 = integer_literal $Builtin.Int8, 2
-  %14 = struct $StaticString (%12 : $Builtin.Word, %11 : $Builtin.Word, %13 : $Builtin.Int8)
-  %15 = string_literal utf8 "Swift/Integers.swift"
-  %16 = integer_literal $Builtin.Word, 20
-  %17 = builtin "ptrtoint_Word"(%15 : $Builtin.RawPointer) : $Builtin.Word
-  %18 = integer_literal $Builtin.Int8, 2
-  %19 = struct $StaticString (%17 : $Builtin.Word, %16 : $Builtin.Word, %18 : $Builtin.Int8)
-  %20 = integer_literal $Builtin.Int64, 1498
-  %21 = struct $UInt (%20 : $Builtin.Int64)
-  %22 = builtin "assert_configuration"() : $Builtin.Int32
-  %23 = integer_literal $Builtin.Int32, 0
-  %24 = builtin "cmp_eq_Int32"(%22 : $Builtin.Int32, %23 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %24, bb2, bb1
-
-bb1:
-  %26 = builtin "assert_configuration"() : $Builtin.Int32
-  %27 = integer_literal $Builtin.Int32, 1
-  %28 = builtin "cmp_eq_Int32"(%26 : $Builtin.Int32, %27 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %28, bb83, bb84
-
-bb2:
-  %30 = integer_literal $Builtin.Int64, 2
-  %31 = integer_literal $Builtin.Int64, 36
-  %34 = destructure_struct %1 : $Int
-  %35 = builtin "cmp_slt_Int64"(%34 : $Builtin.Int64, %30 : $Builtin.Int64) : $Builtin.Int1
-  cond_br %35, bb3, bb4
-
-bb3:
-  %37 = integer_literal $Builtin.Int1, 0
-  br bb5(%37 : $Builtin.Int1)
-
-bb4:
-  %39 = builtin "cmp_slt_Int64"(%31 : $Builtin.Int64, %34 : $Builtin.Int64) : $Builtin.Int1
-  %40 = integer_literal $Builtin.Int1, -1
-  %41 = builtin "xor_Int1"(%39 : $Builtin.Int1, %40 : $Builtin.Int1) : $Builtin.Int1
-  br bb5(%41 : $Builtin.Int1)
-
-bb5(%43 : $Builtin.Int1):
-  %44 = integer_literal $Builtin.Int1, -1
-  %45 = builtin "int_expect_Int1"(%43 : $Builtin.Int1, %44 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %45, bb7, bb6
-
-bb6:
-  %47 = string_literal utf8 "Fatal error"
-  %48 = integer_literal $Builtin.Word, 11
-  %49 = builtin "ptrtoint_Word"(%47 : $Builtin.RawPointer) : $Builtin.Word
-  %50 = integer_literal $Builtin.Int8, 2
-  %51 = struct $StaticString (%49 : $Builtin.Word, %48 : $Builtin.Word, %50 : $Builtin.Int8)
-  %52 = builtin "assert_configuration"() : $Builtin.Int32
-  %53 = integer_literal $Builtin.Int32, 0
-  %54 = builtin "cmp_eq_Int32"(%52 : $Builtin.Int32, %53 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %54, bb8, bb9
-
-bb7:
-  br bb11
-
-bb8:
-  %57 = integer_literal $Builtin.Int32, 1
-  %58 = struct $UInt32 (%57 : $Builtin.Int32)
-  br bb10(%58 : $UInt32)
-
-bb9:
-  %60 = integer_literal $Builtin.Int32, 0
-  %61 = struct $UInt32 (%60 : $Builtin.Int32)
-  br bb10(%61 : $UInt32)
-
-bb10(%63 : $UInt32):
-  %64 = function_ref @$ss17_assertionFailure__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %65 = apply %64(%51, %14, %19, %21, %63) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb11:
-  %67 = witness_method $T, #BinaryInteger.bitWidth!getter : <Self where Self : BinaryInteger> (Self) -> () -> Int : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %68 = apply %67<T>(%0) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %69 = integer_literal $Builtin.Int64, 64
-  %70 = struct_extract %68 : $Int, #Int._value
-  %71 = builtin "cmp_slt_Int64"(%69 : $Builtin.Int64, %70 : $Builtin.Int64) : $Builtin.Int1
-  cond_br %71, bb13, bb12
-
-bb12:
-  %75 = destructure_struct %1 : $Int
-  %77 = struct $Int64 (%75 : $Builtin.Int64)
-  %79 = metatype $@thick T.Type
-  %80 = witness_method $T, #BinaryInteger.isSigned!getter : <Self where Self : BinaryInteger> (Self.Type) -> () -> Bool : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %81 = apply %80<T>(%79) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %82 = struct_extract %81 : $Bool, #Bool._value
-  cond_br %82, bb14, bb15
-
-bb13:
-  %84 = metatype $@thick T.Type
-  %85 = integer_literal $Builtin.IntLiteral, 0
-  %86 = metatype $@thick T.IntegerLiteralType.Type
-  %87 = alloc_stack $T.IntegerLiteralType
-  %88 = witness_method $T.IntegerLiteralType, #_ExpressibleByBuiltinIntegerLiteral.init!allocator : <Self where Self : _ExpressibleByBuiltinIntegerLiteral> (Self.Type) -> (Builtin.IntLiteral) -> Self : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %89 = apply %88<T.IntegerLiteralType>(%87, %85, %86) : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %90 = metatype $@thick T.Type
-  %91 = alloc_stack $T
-  %92 = witness_method $T, #ExpressibleByIntegerLiteral.init!allocator : <Self where Self : ExpressibleByIntegerLiteral> (Self.Type) -> (Self.IntegerLiteralType) -> Self : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %93 = apply %92<T>(%91, %87, %90) : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %94 = witness_method $T, #Equatable."==" : <Self where Self : Equatable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %95 = apply %94<T>(%0, %91, %84) : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %91 : $*T
-  dealloc_stack %91 : $*T
-  dealloc_stack %87 : $*T.IntegerLiteralType
-  %99 = struct_extract %95 : $Bool, #Bool._value
-  cond_br %99, bb17, bb18
-
-bb14:
-  %102 = witness_method $T, #BinaryInteger._lowWord!getter : <Self where Self : BinaryInteger> (Self) -> () -> UInt : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  %103 = apply %102<T>(%0) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  destroy_addr %0 : $*T
-  %105 = struct_extract %103 : $UInt, #UInt._value
-  %107 = struct $Int64 (%105 : $Builtin.Int64)
-  %108 = function_ref @$ss14_int64ToString_5radix9uppercaseSSs5Int64V_AESbtF : $@convention(thin) (Int64, Int64, Bool) -> @owned String
-  %109 = apply %108(%107, %77, %2) : $@convention(thin) (Int64, Int64, Bool) -> @owned String
-  br bb16(%109 : $String)
-
-bb15:
-  %112 = witness_method $T, #BinaryInteger._lowWord!getter : <Self where Self : BinaryInteger> (Self) -> () -> UInt : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  %113 = apply %112<T>(%0) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  destroy_addr %0 : $*T
-  %116 = struct_extract %113 : $UInt, #UInt._value
-  %119 = struct $UInt64 (%116 : $Builtin.Int64)
-  %120 = function_ref @$ss15_uint64ToString_5radix9uppercaseSSs6UInt64V_s5Int64VSbtF : $@convention(thin) (UInt64, Int64, Bool) -> @owned String
-  %121 = apply %120(%119, %77, %2) : $@convention(thin) (UInt64, Int64, Bool) -> @owned String
-  br bb16(%121 : $String)
-
-bb16(%123 : @owned $String):
-  return %123 : $String
-
-bb17:
-  destroy_addr %0 : $*T
-  %126 = string_literal utf8 "0"
-  %127 = integer_literal $Builtin.Word, 1
-  %128 = integer_literal $Builtin.Int1, -1
-  %129 = function_ref @$sSS21_builtinStringLiteral17utf8CodeUnitCount7isASCIISSBp_BwBi1_tcfC : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
-  %130 = apply %129(%126, %127, %128, %3) : $@convention(method) (Builtin.RawPointer, Builtin.Word, Builtin.Int1, @thin String.Type) -> @owned String
-  br bb16(%130 : $String)
-
-bb18:
-  %132 = struct_extract %1 : $Int, #Int._value
-  %133 = builtin "int_ctpop_Int64"(%132 : $Builtin.Int64) : $Builtin.Int64
-  %134 = integer_literal $Builtin.Int64, 1
-  %135 = builtin "cmp_eq_Int64"(%133 : $Builtin.Int64, %134 : $Builtin.Int64) : $Builtin.Int1
-  %137 = alloc_stack $T.Magnitude, let, name "radix_"
-  %138 = metatype $@thick T.Magnitude.Type
-  %139 = alloc_stack $Int
-  store %1 to [trivial] %139 : $*Int
-  %141 = witness_method $T.Magnitude, #BinaryInteger.init!allocator : <Self where Self : BinaryInteger><T where T : BinaryInteger> (Self.Type) -> (T) -> Self : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %142 = apply %141<T.Magnitude, Int>(%137, %139, %138) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %139 : $*Int
-  %144 = integer_literal $Builtin.Int64, 10
-  %145 = struct_extract %1 : $Int, #Int._value
-  %146 = builtin "cmp_slt_Int64"(%144 : $Builtin.Int64, %145 : $Builtin.Int64) : $Builtin.Int1
-  %148 = metatype $@thick T.Type
-  %149 = witness_method $T, #BinaryInteger.isSigned!getter : <Self where Self : BinaryInteger> (Self.Type) -> () -> Bool : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %150 = apply %149<T>(%148) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %151 = alloc_stack $T
-  copy_addr %0 to [init] %151 : $*T
-  %153 = struct_extract %150 : $Bool, #Bool._value
-  cond_br %153, bb19, bb20
-
-bb19:
-  %155 = metatype $@thick T.Type
-  %156 = integer_literal $Builtin.IntLiteral, 0
-  %157 = metatype $@thick T.IntegerLiteralType.Type
-  %158 = alloc_stack $T.IntegerLiteralType
-  %159 = witness_method $T.IntegerLiteralType, #_ExpressibleByBuiltinIntegerLiteral.init!allocator : <Self where Self : _ExpressibleByBuiltinIntegerLiteral> (Self.Type) -> (Builtin.IntLiteral) -> Self : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %160 = apply %159<T.IntegerLiteralType>(%158, %156, %157) : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %161 = metatype $@thick T.Type
-  %162 = alloc_stack $T
-  %163 = witness_method $T, #ExpressibleByIntegerLiteral.init!allocator : <Self where Self : ExpressibleByIntegerLiteral> (Self.Type) -> (Self.IntegerLiteralType) -> Self : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %164 = apply %163<T>(%162, %158, %161) : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %165 = witness_method $T, #Comparable."<" : <Self where Self : Comparable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %166 = apply %165<T>(%151, %162, %155) : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %162 : $*T
-  destroy_addr %151 : $*T
-  dealloc_stack %162 : $*T
-  dealloc_stack %158 : $*T.IntegerLiteralType
-  br bb21(%166 : $Bool)
-
-bb20:
-  destroy_addr %151 : $*T
-  %173 = integer_literal $Builtin.Int1, 0
-  %174 = struct $Bool (%173 : $Builtin.Int1)
-  br bb21(%174 : $Bool)
-
-bb21(%176 : $Bool):
-  dealloc_stack %151 : $*T
-  %179 = alloc_stack $T.Magnitude, var, name "value"
-  %180 = witness_method $T, #Numeric.magnitude!getter : <Self where Self : Numeric> (Self) -> () -> Self.Magnitude : $@convention(witness_method: Numeric) <τ_0_0 where τ_0_0 : Numeric> (@in_guaranteed τ_0_0) -> @out τ_0_0.Magnitude
-  %181 = apply %180<T>(%179, %0) : $@convention(witness_method: Numeric) <τ_0_0 where τ_0_0 : Numeric> (@in_guaranteed τ_0_0) -> @out τ_0_0.Magnitude
-  %182 = alloc_stack $Array<UInt8>, var, name "result"
-  %183 = integer_literal $Builtin.Int64, 0
-  %184 = struct $Int (%183 : $Builtin.Int64)
-  %186 = metatype $@thin Array<UInt8>.Type
-  %187 = function_ref @$sSa22_allocateUninitializedySayxG_SpyxGtSiFZs5UInt8V_Tg5 : $@convention(method) (Int, @thin Array<UInt8>.Type) -> (@owned Array<UInt8>, UnsafeMutablePointer<UInt8>)
-  %188 = apply %187(%184, %186) : $@convention(method) (Int, @thin Array<UInt8>.Type) -> (@owned Array<UInt8>, UnsafeMutablePointer<UInt8>)
-  (%189, %190) = destructure_tuple %188 : $(Array<UInt8>, UnsafeMutablePointer<UInt8>)
-  %192 = struct_extract %190 : $UnsafeMutablePointer<UInt8>, #UnsafeMutablePointer._rawValue
-  %193 = tuple (%189 : $Array<UInt8>, %192 : $Builtin.RawPointer)
-  (%194, %195) = destructure_tuple %193 : $(Array<UInt8>, Builtin.RawPointer)
-  store %194 to [init] %182 : $*Array<UInt8>
-  br bb22
-
-bb22:
-  %198 = alloc_stack $T.Magnitude
-  copy_addr %179 to [init] %198 : $*T.Magnitude
-  %200 = integer_literal $Builtin.Int64, 0
-  %201 = struct $Int (%200 : $Builtin.Int64)
-  %202 = metatype $@thick T.Magnitude.Type
-  %203 = witness_method $T.Magnitude, #BinaryInteger.isSigned!getter : <Self where Self : BinaryInteger> (Self.Type) -> () -> Bool : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %204 = apply %203<T.Magnitude>(%202) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %205 = alloc_stack $T.Magnitude
-  copy_addr %198 to [init] %205 : $*T.Magnitude
-  %207 = struct_extract %204 : $Bool, #Bool._value
-  cond_br %207, bb23, bb24
-
-bb23:
-  %209 = metatype $@thick T.Magnitude.Type
-  %210 = integer_literal $Builtin.IntLiteral, 0
-  %211 = metatype $@thick T.Magnitude.IntegerLiteralType.Type
-  %212 = alloc_stack $T.Magnitude.IntegerLiteralType
-  %213 = witness_method $T.Magnitude.IntegerLiteralType, #_ExpressibleByBuiltinIntegerLiteral.init!allocator : <Self where Self : _ExpressibleByBuiltinIntegerLiteral> (Self.Type) -> (Builtin.IntLiteral) -> Self : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %214 = apply %213<T.Magnitude.IntegerLiteralType>(%212, %210, %211) : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %215 = metatype $@thick T.Magnitude.Type
-  %216 = alloc_stack $T.Magnitude
-  %217 = witness_method $T.Magnitude, #ExpressibleByIntegerLiteral.init!allocator : <Self where Self : ExpressibleByIntegerLiteral> (Self.Type) -> (Self.IntegerLiteralType) -> Self : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %218 = apply %217<T.Magnitude>(%216, %212, %215) : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %219 = witness_method $T.Magnitude, #Comparable."<" : <Self where Self : Comparable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %220 = apply %219<T.Magnitude>(%205, %216, %209) : $@convention(witness_method: Comparable) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %216 : $*T.Magnitude
-  destroy_addr %205 : $*T.Magnitude
-  dealloc_stack %216 : $*T.Magnitude
-  dealloc_stack %212 : $*T.Magnitude.IntegerLiteralType
-  br bb25(%220 : $Bool)
-
-bb24:
-  destroy_addr %205 : $*T.Magnitude
-  %227 = integer_literal $Builtin.Int1, 0
-  %228 = struct $Bool (%227 : $Builtin.Int1)
-  br bb25(%228 : $Bool)
-
-bb25(%230 : $Bool):
-  dealloc_stack %205 : $*T.Magnitude
-  %232 = struct_extract %230 : $Bool, #Bool._value
-  cond_br %232, bb26, bb27
-
-bb26:
-  destroy_addr %198 : $*T.Magnitude
-  %235 = integer_literal $Builtin.Int1, 0
-  %236 = struct $Bool (%235 : $Builtin.Int1)
-  br bb28(%236 : $Bool)
-
-bb27:
-  %238 = witness_method $T.Magnitude, #BinaryInteger.bitWidth!getter : <Self where Self : BinaryInteger> (Self) -> () -> Int : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %239 = apply %238<T.Magnitude>(%198) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %240 = integer_literal $Builtin.Int64, 64
-  %241 = struct_extract %239 : $Int, #Int._value
-  %242 = builtin "cmp_slt_Int64"(%241 : $Builtin.Int64, %240 : $Builtin.Int64) : $Builtin.Int1
-  cond_br %242, bb77, bb78
-
-bb28(%244 : $Bool):
-  %245 = struct_extract %244 : $Bool, #Bool._value
-  dealloc_stack %198 : $*T.Magnitude
-  cond_br %245, bb56, bb29
-
-bb29:
-  %248 = alloc_stack $T.Magnitude, let, name "quotient"
-  %249 = alloc_stack $T.Magnitude, let, name "remainder"
-  %254 = alloc_stack $(T.Magnitude, T.Magnitude)
-  cond_br %135, bb30, bb31
-
-bb30:
-  %256 = tuple_element_addr %254 : $*(T.Magnitude, T.Magnitude), 0
-  %257 = tuple_element_addr %254 : $*(T.Magnitude, T.Magnitude), 1
-  %258 = metatype $@thick T.Magnitude.Type
-  %259 = struct_extract %1 : $Int, #Int._value
-  %260 = integer_literal $Builtin.Int1, 0
-  %261 = builtin "int_cttz_Int64"(%259 : $Builtin.Int64, %260 : $Builtin.Int1) : $Builtin.Int64
-  %262 = struct $Int (%261 : $Builtin.Int64)
-  %263 = alloc_stack $Int
-  store %262 to [trivial] %263 : $*Int
-  %265 = witness_method $T.Magnitude, #BinaryInteger.">>" : <Self where Self : BinaryInteger><RHS where RHS : BinaryInteger> (Self.Type) -> (Self, RHS) -> Self : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in_guaranteed τ_0_0, @in_guaranteed τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %266 = apply %265<T.Magnitude, Int>(%256, %179, %263, %258) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in_guaranteed τ_0_0, @in_guaranteed τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %263 : $*Int
-  %268 = metatype $@thick T.Magnitude.Type
-  %269 = alloc_stack $T.Magnitude
-  %270 = metatype $@thick T.Magnitude.Type
-  %271 = integer_literal $Builtin.IntLiteral, 1
-  %272 = metatype $@thick T.Magnitude.IntegerLiteralType.Type
-  %273 = alloc_stack $T.Magnitude.IntegerLiteralType
-  %274 = witness_method $T.Magnitude.IntegerLiteralType, #_ExpressibleByBuiltinIntegerLiteral.init!allocator : <Self where Self : _ExpressibleByBuiltinIntegerLiteral> (Self.Type) -> (Builtin.IntLiteral) -> Self : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %275 = apply %274<T.Magnitude.IntegerLiteralType>(%273, %271, %272) : $@convention(witness_method: _ExpressibleByBuiltinIntegerLiteral) <τ_0_0 where τ_0_0 : _ExpressibleByBuiltinIntegerLiteral> (Builtin.IntLiteral, @thick τ_0_0.Type) -> @out τ_0_0
-  %276 = metatype $@thick T.Magnitude.Type
-  %277 = alloc_stack $T.Magnitude
-  %278 = witness_method $T.Magnitude, #ExpressibleByIntegerLiteral.init!allocator : <Self where Self : ExpressibleByIntegerLiteral> (Self.Type) -> (Self.IntegerLiteralType) -> Self : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %279 = apply %278<T.Magnitude>(%277, %273, %276) : $@convention(witness_method: ExpressibleByIntegerLiteral) <τ_0_0 where τ_0_0 : ExpressibleByIntegerLiteral> (@in τ_0_0.IntegerLiteralType, @thick τ_0_0.Type) -> @out τ_0_0
-  %280 = witness_method $T.Magnitude, #AdditiveArithmetic."-" : <Self where Self : AdditiveArithmetic> (Self.Type) -> (Self, Self) -> Self : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %281 = apply %280<T.Magnitude>(%269, %137, %277, %270) : $@convention(witness_method: AdditiveArithmetic) <τ_0_0 where τ_0_0 : AdditiveArithmetic> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
-  destroy_addr %277 : $*T.Magnitude
-  dealloc_stack %277 : $*T.Magnitude
-  dealloc_stack %273 : $*T.Magnitude.IntegerLiteralType
-  %285 = witness_method $T.Magnitude, #BinaryInteger."&" : <Self where Self : BinaryInteger> (Self.Type) -> (Self, Self) -> Self : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %286 = apply %285<T.Magnitude>(%257, %179, %269, %268) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> @out τ_0_0
-  destroy_addr %269 : $*T.Magnitude
-  destroy_addr %179 : $*T.Magnitude
-  dealloc_stack %269 : $*T.Magnitude
-  br bb32
-
-bb31:
-  %291 = alloc_stack $T.Magnitude
-  %292 = alloc_stack $T.Magnitude
-  %293 = witness_method $T.Magnitude, #BinaryInteger.quotientAndRemainder : <Self where Self : BinaryInteger> (Self) -> (Self) -> (quotient: Self, remainder: Self) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0) -> (@out τ_0_0, @out τ_0_0)
-  %294 = apply %293<T.Magnitude>(%291, %292, %137, %179) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0) -> (@out τ_0_0, @out τ_0_0)
-  destroy_addr %179 : $*T.Magnitude
-  %296 = tuple_element_addr %254 : $*(T.Magnitude, T.Magnitude), 0
-  %297 = tuple_element_addr %254 : $*(T.Magnitude, T.Magnitude), 1
-  copy_addr [take] %291 to [init] %296 : $*T.Magnitude
-  copy_addr [take] %292 to [init] %297 : $*T.Magnitude
-  dealloc_stack %292 : $*T.Magnitude
-  dealloc_stack %291 : $*T.Magnitude
-  br bb32
-
-bb32:
-  %303 = tuple_element_addr %254 : $*(T.Magnitude, T.Magnitude), 0
-  %304 = tuple_element_addr %254 : $*(T.Magnitude, T.Magnitude), 1
-  copy_addr [take] %303 to [init] %248 : $*T.Magnitude
-  copy_addr [take] %304 to [init] %249 : $*T.Magnitude
-  dealloc_stack %254 : $*(T.Magnitude, T.Magnitude)
-  %309 = witness_method $T.Magnitude, #BinaryInteger._lowWord!getter : <Self where Self : BinaryInteger> (Self) -> () -> UInt : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  %310 = apply %309<T.Magnitude>(%249) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  destroy_addr %249 : $*T.Magnitude
-  %313 = struct_extract %310 : $UInt, #UInt._value
-  %314 = builtin "truncOrBitCast_Int64_Int8"(%313 : $Builtin.Int64) : $Builtin.Int8
-  cond_br %146, bb34, bb33
-
-bb33:
-  %321 = integer_literal $Builtin.Int1, -1
-  br bb35(%321 : $Builtin.Int1)
-
-bb34:
-  %323 = integer_literal $Builtin.Int8, 10
-  %324 = builtin "cmp_ult_Int8"(%314 : $Builtin.Int8, %323 : $Builtin.Int8) : $Builtin.Int1
-  br bb35(%324 : $Builtin.Int1)
-
-bb35(%326 : $Builtin.Int1):
-  cond_br %326, bb36, bb37
-
-bb36:
-  %328 = builtin "assert_configuration"() : $Builtin.Int32
-  %329 = integer_literal $Builtin.Int32, 0
-  %330 = builtin "cmp_eq_Int32"(%328 : $Builtin.Int32, %329 : $Builtin.Int32) : $Builtin.Int1
-  %331 = integer_literal $Builtin.Int8, 48
-  br bb38(%331 : $Builtin.Int8)
-
-bb37:
-  %336 = struct_extract %2 : $Bool, #Bool._value
-  cond_br %336, bb54, bb55
-
-bb38(%338 : $Builtin.Int8):
-  %339 = integer_literal $Builtin.Int1, 0
-  %340 = builtin "uadd_with_overflow_Int8"(%338 : $Builtin.Int8, %314 : $Builtin.Int8, %339 : $Builtin.Int1) : $(Builtin.Int8, Builtin.Int1)
-  (%341, %342) = destructure_tuple %340 : $(Builtin.Int8, Builtin.Int1)
-  %343 = struct $UInt8 (%341 : $Builtin.Int8)
-  %346 = function_ref @$sSa034_makeUniqueAndReserveCapacityIfNotB0yyFs5UInt8V_Tg5 : $@convention(method) (@inout Array<UInt8>) -> ()
-  %347 = apply %346(%182) : $@convention(method) (@inout Array<UInt8>) -> ()
-  %348 = struct_element_addr %182 : $*Array<UInt8>, #Array._buffer
-  %349 = struct_element_addr %348 : $*_ArrayBuffer<UInt8>, #_ArrayBuffer._storage
-  %350 = struct_element_addr %349 : $*_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
-  %351 = load_borrow %350 : $*Builtin.BridgeObject
-  %352 = string_literal utf8 "Swift/BridgeStorage.swift"
-  %353 = integer_literal $Builtin.Word, 25
-  %354 = builtin "ptrtoint_Word"(%352 : $Builtin.RawPointer) : $Builtin.Word
-  %355 = integer_literal $Builtin.Int8, 2
-  %356 = struct $StaticString (%354 : $Builtin.Word, %353 : $Builtin.Word, %355 : $Builtin.Int8)
-  %357 = integer_literal $Builtin.Int64, 127
-  %358 = struct $UInt (%357 : $Builtin.Int64)
-  %359 = string_literal utf8 ""
-  %360 = integer_literal $Builtin.Word, 0
-  %361 = builtin "ptrtoint_Word"(%359 : $Builtin.RawPointer) : $Builtin.Word
-  %362 = struct $StaticString (%361 : $Builtin.Word, %360 : $Builtin.Word, %355 : $Builtin.Int8)
-  %363 = classify_bridge_object %351 : $Builtin.BridgeObject
-  (%364, %365) = destructure_tuple %363 : $(Builtin.Int1, Builtin.Int1)
-  %366 = builtin "or_Int1"(%364 : $Builtin.Int1, %365 : $Builtin.Int1) : $Builtin.Int1
-  %367 = integer_literal $Builtin.Int1, 0
-  %368 = builtin "int_expect_Int1"(%366 : $Builtin.Int1, %367 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %368, bb39, bb40
-
-bb39:
-  %370 = string_literal utf8 "Fatal error"
-  %371 = integer_literal $Builtin.Word, 11
-  %372 = builtin "ptrtoint_Word"(%370 : $Builtin.RawPointer) : $Builtin.Word
-  %373 = struct $StaticString (%372 : $Builtin.Word, %371 : $Builtin.Word, %355 : $Builtin.Int8)
-  %374 = builtin "assert_configuration"() : $Builtin.Int32
-  %375 = integer_literal $Builtin.Int32, 0
-  %376 = builtin "cmp_eq_Int32"(%374 : $Builtin.Int32, %375 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %376, bb41, bb42
-
-bb40:
-  %378 = integer_literal $Builtin.Int64, 128
-  %379 = struct $UInt (%378 : $Builtin.Int64)
-  %382 = bridge_object_to_word %351 : $Builtin.BridgeObject to $Builtin.Word
-  %383 = builtin "zextOrBitCast_Word_Int64"(%382 : $Builtin.Word) : $Builtin.Int64
-  %384 = integer_literal $Builtin.Int64, 8070450532247928839
-  %385 = builtin "and_Int64"(%383 : $Builtin.Int64, %384 : $Builtin.Int64) : $Builtin.Int64
-  %386 = integer_literal $Builtin.Int64, 0
-  %387 = builtin "cmp_eq_Int64"(%385 : $Builtin.Int64, %386 : $Builtin.Int64) : $Builtin.Int1
-  %388 = integer_literal $Builtin.Int1, -1
-  %389 = builtin "int_expect_Int1"(%387 : $Builtin.Int1, %388 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %389, bb44, bb45
-
-bb41:
-  %391 = integer_literal $Builtin.Int32, 1
-  %392 = struct $UInt32 (%391 : $Builtin.Int32)
-  br bb43(%392 : $UInt32)
-
-bb42:
-  %394 = struct $UInt32 (%375 : $Builtin.Int32)
-  br bb43(%394 : $UInt32)
-
-bb43(%396 : $UInt32):
-  %397 = function_ref @$ss18_fatalErrorMessage__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %398 = apply %397(%373, %362, %356, %358, %396) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb44:
-  %400 = unchecked_ref_cast %351 : $Builtin.BridgeObject to $__ContiguousArrayStorageBase
-  %404 = ref_element_addr %400 : $__ContiguousArrayStorageBase, #__ContiguousArrayStorageBase.countAndCapacity
-  %405 = struct_element_addr %404 : $*_ArrayBody, #_ArrayBody._storage
-  %406 = struct_element_addr %405 : $*_SwiftArrayBodyStorage, #_SwiftArrayBodyStorage.count
-  %407 = struct_element_addr %406 : $*Int, #Int._value
-  %408 = load [trivial] %407 : $*Builtin.Int64
-  %409 = string_literal utf8 "Swift/IntegerTypes.swift"
-  %410 = integer_literal $Builtin.Word, 24
-  %411 = builtin "ptrtoint_Word"(%409 : $Builtin.RawPointer) : $Builtin.Word
-  %412 = struct $StaticString (%411 : $Builtin.Word, %410 : $Builtin.Word, %355 : $Builtin.Int8)
-  %413 = integer_literal $Builtin.Int64, 15235
-  %414 = struct $UInt (%413 : $Builtin.Int64)
-  %415 = builtin "cmp_slt_Int64"(%408 : $Builtin.Int64, %386 : $Builtin.Int64) : $Builtin.Int1
-  %416 = builtin "int_expect_Int1"(%415 : $Builtin.Int1, %367 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %416, bb46, bb47
-
-bb45:
-  %418 = string_literal utf8 "Fatal error"
-  %419 = integer_literal $Builtin.Word, 11
-  %420 = builtin "ptrtoint_Word"(%418 : $Builtin.RawPointer) : $Builtin.Word
-  %421 = struct $StaticString (%420 : $Builtin.Word, %419 : $Builtin.Word, %355 : $Builtin.Int8)
-  %422 = builtin "assert_configuration"() : $Builtin.Int32
-  %423 = integer_literal $Builtin.Int32, 0
-  %424 = builtin "cmp_eq_Int32"(%422 : $Builtin.Int32, %423 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %424, bb51, bb52
-
-bb46:
-  %426 = string_literal utf8 "Fatal error"
-  %427 = integer_literal $Builtin.Word, 11
-  %428 = builtin "ptrtoint_Word"(%426 : $Builtin.RawPointer) : $Builtin.Word
-  %429 = struct $StaticString (%428 : $Builtin.Word, %427 : $Builtin.Word, %355 : $Builtin.Int8)
-  %430 = builtin "assert_configuration"() : $Builtin.Int32
-  %431 = integer_literal $Builtin.Int32, 0
-  %432 = builtin "cmp_eq_Int32"(%430 : $Builtin.Int32, %431 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %432, bb48, bb49
-
-bb47:
-  %434 = builtin "assumeNonNegative_Int64"(%408 : $Builtin.Int64) : $Builtin.Int64
-  %435 = struct $Int (%434 : $Builtin.Int64)
-  end_borrow %351 : $Builtin.BridgeObject
-  %438 = function_ref @$sSa36_reserveCapacityAssumingUniqueBuffer8oldCountySi_tFs5UInt8V_Tg5 : $@convention(method) (Int, @inout Array<UInt8>) -> ()
-  %439 = apply %438(%435, %182) : $@convention(method) (Int, @inout Array<UInt8>) -> ()
-  %440 = function_ref @$sSa37_appendElementAssumeUniqueAndCapacity_03newB0ySi_xntFs5UInt8V_Tg5 : $@convention(method) (Int, UInt8, @inout Array<UInt8>) -> ()
-  %441 = apply %440(%435, %343, %182) : $@convention(method) (Int, UInt8, @inout Array<UInt8>) -> ()
-  %442 = function_ref @$sSa12_endMutationyyFs5UInt8V_Tg5 : $@convention(method) (@inout Array<UInt8>) -> ()
-  %443 = apply %442(%182) : $@convention(method) (@inout Array<UInt8>) -> ()
-  copy_addr [take] %248 to [init] %179 : $*T.Magnitude
-  dealloc_stack %249 : $*T.Magnitude
-  dealloc_stack %248 : $*T.Magnitude
-  br bb22
-
-bb48:
-  %448 = integer_literal $Builtin.Int32, 1
-  %449 = struct $UInt32 (%448 : $Builtin.Int32)
-  br bb50(%449 : $UInt32)
-
-bb49:
-  %451 = struct $UInt32 (%431 : $Builtin.Int32)
-  br bb50(%451 : $UInt32)
-
-bb50(%453 : $UInt32):
-  %454 = function_ref @$ss18_fatalErrorMessage__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %455 = apply %454(%429, %362, %412, %414, %453) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb51:
-  %457 = integer_literal $Builtin.Int32, 1
-  %458 = struct $UInt32 (%457 : $Builtin.Int32)
-  br bb53(%458 : $UInt32)
-
-bb52:
-  %460 = struct $UInt32 (%423 : $Builtin.Int32)
-  br bb53(%460 : $UInt32)
-
-bb53(%462 : $UInt32):
-  %463 = function_ref @$ss18_fatalErrorMessage__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %464 = apply %463(%421, %362, %356, %379, %462) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb54:
-  %466 = builtin "assert_configuration"() : $Builtin.Int32
-  %467 = integer_literal $Builtin.Int32, 0
-  %468 = builtin "cmp_eq_Int32"(%466 : $Builtin.Int32, %467 : $Builtin.Int32) : $Builtin.Int1
-  %469 = integer_literal $Builtin.Int8, 55
-  br bb38(%469 : $Builtin.Int8)
-
-bb55:
-  %472 = builtin "assert_configuration"() : $Builtin.Int32
-  %473 = integer_literal $Builtin.Int32, 0
-  %474 = builtin "cmp_eq_Int32"(%472 : $Builtin.Int32, %473 : $Builtin.Int32) : $Builtin.Int1
-  %475 = integer_literal $Builtin.Int8, 87
-  br bb38(%475 : $Builtin.Int8)
-
-bb56:
-  %478 = struct_extract %176 : $Bool, #Bool._value
-  cond_br %478, bb57, bb58
-
-bb57:
-  %480 = integer_literal $Builtin.Int8, 45
-  %483 = struct $UInt8 (%480 : $Builtin.Int8)
-  %484 = function_ref @$sSa6appendyyxnFs5UInt8V_Tg5 : $@convention(method) (UInt8, @inout Array<UInt8>) -> ()
-  %485 = apply %484(%483, %182) : $@convention(method) (UInt8, @inout Array<UInt8>) -> ()
-  br bb59
-
-bb58:
-  br bb59
-
-bb59:
-  %488 = function_ref @$sSMsSKRzrlE7reverseyyFSays5UInt8VG_Tg5 : $@convention(method) (@inout Array<UInt8>) -> ()
-  %489 = apply %488(%182) : $@convention(method) (@inout Array<UInt8>) -> ()
-  %490 = load [copy] %182 : $*Array<UInt8>
-  %491 = function_ref @$sSzsE12_description5radix9uppercaseSSSi_SbtFSSSRys5UInt8VGXEfU_ : $@convention(thin) (UnsafeBufferPointer<UInt8>) -> @owned String
-  %492 = thin_to_thick_function %491 : $@convention(thin) (UnsafeBufferPointer<UInt8>) -> @owned String to $@noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> @owned String
-  %493 = convert_function %492 : $@noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> @owned String to $@noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> (@owned String, @error Error)
-  %494 = begin_borrow %490 : $Array<UInt8>
-  %496 = struct_extract %494 : $Array<UInt8>, #Array._buffer
-  %497 = alloc_stack $String
-  %500 = metatype $@thin UnsafeBufferPointer<UInt8>.Type
-  %501 = function_ref @$ss12_ArrayBufferV19firstElementAddressSpyxGvgs5UInt8V_Tg5 : $@convention(method) (@guaranteed _ArrayBuffer<UInt8>) -> UnsafeMutablePointer<UInt8>
-  %502 = apply %501(%496) : $@convention(method) (@guaranteed _ArrayBuffer<UInt8>) -> UnsafeMutablePointer<UInt8>
-  %503 = struct_extract %502 : $UnsafeMutablePointer<UInt8>, #UnsafeMutablePointer._rawValue
-  %504 = struct $UnsafePointer<UInt8> (%503 : $Builtin.RawPointer)
-  %505 = enum $Optional<UnsafePointer<UInt8>>, #Optional.some!enumelt, %504 : $UnsafePointer<UInt8>
-  %509 = struct_extract %496 : $_ArrayBuffer<UInt8>, #_ArrayBuffer._storage
-  %511 = string_literal utf8 "Swift/BridgeStorage.swift"
-  %512 = integer_literal $Builtin.Word, 25
-  %513 = builtin "ptrtoint_Word"(%511 : $Builtin.RawPointer) : $Builtin.Word
-  %514 = integer_literal $Builtin.Int8, 2
-  %515 = struct $StaticString (%513 : $Builtin.Word, %512 : $Builtin.Word, %514 : $Builtin.Int8)
-  %516 = integer_literal $Builtin.Int64, 127
-  %517 = struct $UInt (%516 : $Builtin.Int64)
-  %518 = string_literal utf8 ""
-  %519 = integer_literal $Builtin.Word, 0
-  %520 = builtin "ptrtoint_Word"(%518 : $Builtin.RawPointer) : $Builtin.Word
-  %521 = struct $StaticString (%520 : $Builtin.Word, %519 : $Builtin.Word, %514 : $Builtin.Int8)
-  %523 = struct_extract %509 : $_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
-  %524 = classify_bridge_object %523 : $Builtin.BridgeObject
-  (%525, %526) = destructure_tuple %524 : $(Builtin.Int1, Builtin.Int1)
-  %527 = builtin "or_Int1"(%525 : $Builtin.Int1, %526 : $Builtin.Int1) : $Builtin.Int1
-  %528 = integer_literal $Builtin.Int1, 0
-  %529 = builtin "int_expect_Int1"(%527 : $Builtin.Int1, %528 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %529, bb60, bb61
-
-bb60:
-  %531 = string_literal utf8 "Fatal error"
-  %532 = integer_literal $Builtin.Word, 11
-  %533 = builtin "ptrtoint_Word"(%531 : $Builtin.RawPointer) : $Builtin.Word
-  %534 = struct $StaticString (%533 : $Builtin.Word, %532 : $Builtin.Word, %514 : $Builtin.Int8)
-  %535 = builtin "assert_configuration"() : $Builtin.Int32
-  %536 = integer_literal $Builtin.Int32, 0
-  %537 = builtin "cmp_eq_Int32"(%535 : $Builtin.Int32, %536 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %537, bb62, bb63
-
-bb61:
-  %539 = integer_literal $Builtin.Int64, 128
-  %540 = struct $UInt (%539 : $Builtin.Int64)
-  %543 = bridge_object_to_word %523 : $Builtin.BridgeObject to $Builtin.Word
-  %544 = builtin "zextOrBitCast_Word_Int64"(%543 : $Builtin.Word) : $Builtin.Int64
-  %545 = integer_literal $Builtin.Int64, 8070450532247928839
-  %546 = builtin "and_Int64"(%544 : $Builtin.Int64, %545 : $Builtin.Int64) : $Builtin.Int64
-  %547 = integer_literal $Builtin.Int64, 0
-  %548 = builtin "cmp_eq_Int64"(%546 : $Builtin.Int64, %547 : $Builtin.Int64) : $Builtin.Int1
-  %549 = integer_literal $Builtin.Int1, -1
-  %550 = builtin "int_expect_Int1"(%548 : $Builtin.Int1, %549 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %550, bb65, bb66
-
-bb62:
-  %552 = integer_literal $Builtin.Int32, 1
-  %553 = struct $UInt32 (%552 : $Builtin.Int32)
-  br bb64(%553 : $UInt32)
-
-bb63:
-  %555 = struct $UInt32 (%536 : $Builtin.Int32)
-  br bb64(%555 : $UInt32)
-
-bb64(%557 : $UInt32):
-  %558 = function_ref @$ss18_fatalErrorMessage__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %559 = apply %558(%534, %521, %515, %517, %557) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb65:
-  %561 = unchecked_ref_cast %523 : $Builtin.BridgeObject to $__ContiguousArrayStorageBase
-  %564 = ref_element_addr %561 : $__ContiguousArrayStorageBase, #__ContiguousArrayStorageBase.countAndCapacity
-  %565 = struct_element_addr %564 : $*_ArrayBody, #_ArrayBody._storage
-  %566 = struct_element_addr %565 : $*_SwiftArrayBodyStorage, #_SwiftArrayBodyStorage.count
-  %567 = struct_element_addr %566 : $*Int, #Int._value
-  %568 = load [trivial] %567 : $*Builtin.Int64
-  %569 = string_literal utf8 "Swift/IntegerTypes.swift"
-  %570 = integer_literal $Builtin.Word, 24
-  %571 = builtin "ptrtoint_Word"(%569 : $Builtin.RawPointer) : $Builtin.Word
-  %572 = struct $StaticString (%571 : $Builtin.Word, %570 : $Builtin.Word, %514 : $Builtin.Int8)
-  %573 = integer_literal $Builtin.Int64, 15235
-  %574 = struct $UInt (%573 : $Builtin.Int64)
-  %575 = builtin "cmp_slt_Int64"(%568 : $Builtin.Int64, %547 : $Builtin.Int64) : $Builtin.Int1
-  %576 = builtin "int_expect_Int1"(%575 : $Builtin.Int1, %528 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %576, bb67, bb68
-
-bb66:
-  %578 = string_literal utf8 "Fatal error"
-  %579 = integer_literal $Builtin.Word, 11
-  %580 = builtin "ptrtoint_Word"(%578 : $Builtin.RawPointer) : $Builtin.Word
-  %581 = struct $StaticString (%580 : $Builtin.Word, %579 : $Builtin.Word, %514 : $Builtin.Int8)
-  %582 = builtin "assert_configuration"() : $Builtin.Int32
-  %583 = integer_literal $Builtin.Int32, 0
-  %584 = builtin "cmp_eq_Int32"(%582 : $Builtin.Int32, %583 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %584, bb74, bb75
-
-bb67:
-  %586 = string_literal utf8 "Fatal error"
-  %587 = integer_literal $Builtin.Word, 11
-  %588 = builtin "ptrtoint_Word"(%586 : $Builtin.RawPointer) : $Builtin.Word
-  %589 = struct $StaticString (%588 : $Builtin.Word, %587 : $Builtin.Word, %514 : $Builtin.Int8)
-  %590 = builtin "assert_configuration"() : $Builtin.Int32
-  %591 = integer_literal $Builtin.Int32, 0
-  %592 = builtin "cmp_eq_Int32"(%590 : $Builtin.Int32, %591 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %592, bb71, bb72
-
-bb68:
-  %594 = builtin "assumeNonNegative_Int64"(%568 : $Builtin.Int64) : $Builtin.Int64
-  %595 = struct $Int (%594 : $Builtin.Int64)
-  %596 = function_ref @$sSR5start5countSRyxGSPyxGSg_SitcfCs5UInt8V_Tg5 : $@convention(method) (Optional<UnsafePointer<UInt8>>, Int, @thin UnsafeBufferPointer<UInt8>.Type) -> UnsafeBufferPointer<UInt8>
-  %597 = apply %596(%505, %595, %500) : $@convention(method) (Optional<UnsafePointer<UInt8>>, Int, @thin UnsafeBufferPointer<UInt8>.Type) -> UnsafeBufferPointer<UInt8>
-  try_apply %493(%597) : $@noescape @callee_guaranteed (UnsafeBufferPointer<UInt8>) -> (@owned String, @error Error), normal bb69, error bb70
-
-bb69(%599 : @owned $String):
-  destroy_addr %137 : $*T.Magnitude
-  store %599 to [init] %497 : $*String
-  %602 = tuple ()
-  destroy_addr %0 : $*T
-  destroy_addr %179 : $*T.Magnitude
-  %606 = alloc_stack $_ArrayBuffer<UInt8>
-  %607 = store_borrow %496 to %606 : $*_ArrayBuffer<UInt8>
-  %608 = load_borrow %606 : $*_ArrayBuffer<UInt8>
-  fix_lifetime %608 : $_ArrayBuffer<UInt8>
-  end_borrow %608 : $_ArrayBuffer<UInt8>
-  dealloc_stack %606 : $*_ArrayBuffer<UInt8>
-  %612 = load [take] %497 : $*String
-  dealloc_stack %497 : $*String
-  end_borrow %494 : $Array<UInt8>
-  destroy_value %490 : $Array<UInt8>
-  %616 = load [take] %182 : $*Array<UInt8>
-  destroy_value %616 : $Array<UInt8>
-  dealloc_stack %182 : $*Array<UInt8>
-  dealloc_stack %179 : $*T.Magnitude
-  dealloc_stack %137 : $*T.Magnitude
-  br bb16(%612 : $String)
-
-bb70(%622 : @owned $Error):
-  %624 = alloc_stack $_ArrayBuffer<UInt8>
-  %625 = store_borrow %496 to %624 : $*_ArrayBuffer<UInt8>
-  %626 = load_borrow %624 : $*_ArrayBuffer<UInt8>
-  fix_lifetime %626 : $_ArrayBuffer<UInt8>
-  end_borrow %626 : $_ArrayBuffer<UInt8>
-  dealloc_stack %624 : $*_ArrayBuffer<UInt8>
-  dealloc_stack %497 : $*String
-  unreachable
-
-bb71:
-  %632 = integer_literal $Builtin.Int32, 1
-  %633 = struct $UInt32 (%632 : $Builtin.Int32)
-  br bb73(%633 : $UInt32)
-
-bb72:
-  %635 = struct $UInt32 (%591 : $Builtin.Int32)
-  br bb73(%635 : $UInt32)
-
-bb73(%637 : $UInt32):
-  %638 = function_ref @$ss18_fatalErrorMessage__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %639 = apply %638(%589, %521, %572, %574, %637) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb74:
-  %641 = integer_literal $Builtin.Int32, 1
-  %642 = struct $UInt32 (%641 : $Builtin.Int32)
-  br bb76(%642 : $UInt32)
-
-bb75:
-  %644 = struct $UInt32 (%583 : $Builtin.Int32)
-  br bb76(%644 : $UInt32)
-
-bb76(%646 : $UInt32):
-  %647 = function_ref @$ss18_fatalErrorMessage__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %648 = apply %647(%581, %521, %515, %540, %646) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb77:
-  %651 = witness_method $T.Magnitude, #BinaryInteger._lowWord!getter : <Self where Self : BinaryInteger> (Self) -> () -> UInt : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  %652 = apply %651<T.Magnitude>(%198) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  destroy_addr %198 : $*T.Magnitude
-  %654 = struct_extract %652 : $UInt, #UInt._value
-  %656 = builtin "cmp_eq_Int64"(%654 : $Builtin.Int64, %200 : $Builtin.Int64) : $Builtin.Int1
-  %657 = struct $Bool (%656 : $Builtin.Int1)
-  br bb28(%657 : $Bool)
-
-bb78:
-  %659 = witness_method $T.Magnitude, #BinaryInteger.bitWidth!getter : <Self where Self : BinaryInteger> (Self) -> () -> Int : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %660 = apply %659<T.Magnitude>(%198) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> Int
-  %661 = integer_literal $Builtin.Int64, 64
-  %662 = struct_extract %660 : $Int, #Int._value
-  %663 = builtin "cmp_slt_Int64"(%661 : $Builtin.Int64, %662 : $Builtin.Int64) : $Builtin.Int1
-  cond_br %663, bb79, bb80
-
-bb79:
-  %665 = metatype $@thick T.Magnitude.Type
-  %666 = alloc_stack $T.Magnitude
-  %667 = metatype $@thick T.Magnitude.Type
-  %668 = alloc_stack $Int
-  store %201 to [trivial] %668 : $*Int
-  %670 = witness_method $T.Magnitude, #BinaryInteger.init!allocator : <Self where Self : BinaryInteger><T where T : BinaryInteger> (Self.Type) -> (T) -> Self : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %671 = apply %670<T.Magnitude, Int>(%666, %668, %667) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %668 : $*Int
-  %673 = witness_method $T.Magnitude, #Equatable."==" : <Self where Self : Equatable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %674 = apply %673<T.Magnitude>(%198, %666, %665) : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %666 : $*T.Magnitude
-  destroy_addr %198 : $*T.Magnitude
-  dealloc_stack %666 : $*T.Magnitude
-  br bb28(%674 : $Bool)
-
-bb80:
-  %679 = metatype $@thick T.Magnitude.Type
-  %680 = witness_method $T.Magnitude, #BinaryInteger.isSigned!getter : <Self where Self : BinaryInteger> (Self.Type) -> () -> Bool : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %681 = apply %680<T.Magnitude>(%679) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@thick τ_0_0.Type) -> Bool
-  %682 = struct_extract %681 : $Bool, #Bool._value
-  cond_br %682, bb81, bb82
-
-bb81:
-  %685 = witness_method $T.Magnitude, #BinaryInteger._lowWord!getter : <Self where Self : BinaryInteger> (Self) -> () -> UInt : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  %686 = apply %685<T.Magnitude>(%198) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger> (@in_guaranteed τ_0_0) -> UInt
-  destroy_addr %198 : $*T.Magnitude
-  %688 = struct_extract %686 : $UInt, #UInt._value
-  %690 = builtin "cmp_eq_Int64"(%688 : $Builtin.Int64, %200 : $Builtin.Int64) : $Builtin.Int1
-  %691 = struct $Bool (%690 : $Builtin.Int1)
-  br bb28(%691 : $Bool)
-
-bb82:
-  %693 = metatype $@thick T.Magnitude.Type
-  %694 = alloc_stack $T.Magnitude
-  %695 = metatype $@thick T.Magnitude.Type
-  %696 = alloc_stack $Int
-  store %201 to [trivial] %696 : $*Int
-  %698 = witness_method $T.Magnitude, #BinaryInteger.init!allocator : <Self where Self : BinaryInteger><T where T : BinaryInteger> (Self.Type) -> (T) -> Self : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  %699 = apply %698<T.Magnitude, Int>(%694, %696, %695) : $@convention(witness_method: BinaryInteger) <τ_0_0 where τ_0_0 : BinaryInteger><τ_1_0 where τ_1_0 : BinaryInteger> (@in τ_1_0, @thick τ_0_0.Type) -> @out τ_0_0
-  dealloc_stack %696 : $*Int
-  %701 = witness_method $T.Magnitude, #Equatable."==" : <Self where Self : Equatable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %702 = apply %701<T.Magnitude>(%198, %694, %693) : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  destroy_addr %694 : $*T.Magnitude
-  destroy_addr %198 : $*T.Magnitude
-  dealloc_stack %694 : $*T.Magnitude
-  br bb28(%702 : $Bool)
-
-bb83:
-  %707 = integer_literal $Builtin.Int64, 2
-  %708 = integer_literal $Builtin.Int64, 36
-  %711 = destructure_struct %1 : $Int
-  %712 = builtin "cmp_slt_Int64"(%711 : $Builtin.Int64, %707 : $Builtin.Int64) : $Builtin.Int1
-  cond_fail %712 : $Builtin.Int1, "Radix must be between 2 and 36"
-  %714 = builtin "cmp_slt_Int64"(%708 : $Builtin.Int64, %711 : $Builtin.Int64) : $Builtin.Int1
-  cond_fail %714 : $Builtin.Int1, "Radix must be between 2 and 36"
-  br bb11
-
-bb84:
-  br bb11
-}
-
-// CHECK-LABEL: sil [ossa] @$ss23LazyPrefixWhileSequenceVsSlRzrlE5IndexV5endOfADyx_Gx_tcfC : {{.*}} {
-// CHECKDEB:   debug_value
-// CHECKOPT-NOT: debug_value
-// CHECK-LABEL: } // end sil function '$ss23LazyPrefixWhileSequenceVsSlRzrlE5IndexV5endOfADyx_Gx_tcfC'
-sil [ossa] @$ss23LazyPrefixWhileSequenceVsSlRzrlE5IndexV5endOfADyx_Gx_tcfC : $@convention(method) <Base where Base : Collection> (@in Base, @thin LazyPrefixWhileSequence<Base>.Index.Type) -> @out LazyPrefixWhileSequence<Base>.Index {
-bb0(%0 : $*LazyPrefixWhileSequence<Base>.Index, %1 : $*Base, %2 : $@thin LazyPrefixWhileSequence<Base>.Index.Type):
-  %4 = alloc_stack $LazyPrefixWhileSequence<Base>.Index, var, name "self", implicit 
-  debug_value %1 : $*Base, let, name "endOf", argno 1, expr op_deref 
-  %6 = metatype $@thin LazyPrefixWhileSequence<Base>._IndexRepresentation.Type
-  %7 = alloc_stack $LazyPrefixWhileSequence<Base>._IndexRepresentation 
-  inject_enum_addr %7 : $*LazyPrefixWhileSequence<Base>._IndexRepresentation, #LazyPrefixWhileSequence._IndexRepresentation.pastEnd!enumelt 
-  %9 = struct_element_addr %4 : $*LazyPrefixWhileSequence<Base>.Index, #LazyPrefixWhileSequence.Index._value 
-  destroy_addr %1 : $*Base                        
-  copy_addr [take] %7 to [init] %9 : $*LazyPrefixWhileSequence<Base>._IndexRepresentation 
-  dealloc_stack %7 : $*LazyPrefixWhileSequence<Base>._IndexRepresentation 
-  copy_addr [take] %4 to [init] %0 : $*LazyPrefixWhileSequence<Base>.Index 
-  dealloc_stack %4 : $*LazyPrefixWhileSequence<Base>.Index 
-  %14 = tuple ()                                  
-  return %14 : $()                                
-}
-
-// CHECK-LABEL: sil [ossa] @$sSMsSKRzrlE14_insertionSort6within9sortedEnd2byySny5IndexSlQzG_AFSb7ElementSTQz_AItKXEtKFSays7UnicodeO6ScalarV6scalar_AK9_NormDataV04normM0tG_Tg5 : {{.*}} {
-// CHECK-LABEL: } // end sil function '$sSMsSKRzrlE14_insertionSort6within9sortedEnd2byySny5IndexSlQzG_AFSb7ElementSTQz_AItKXEtKFSays7UnicodeO6ScalarV6scalar_AK9_NormDataV04normM0tG_Tg5'
-sil [ossa] @$sSMsSKRzrlE14_insertionSort6within9sortedEnd2byySny5IndexSlQzG_AFSb7ElementSTQz_AItKXEtKFSays7UnicodeO6ScalarV6scalar_AK9_NormDataV04normM0tG_Tg5 : $@convention(method) (Range<Int>, Int, @noescape @callee_guaranteed @substituted <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_1) -> (Bool, @error Error) for <(scalar: Unicode.Scalar, normData: Unicode._NormData), (scalar: Unicode.Scalar, normData: Unicode._NormData)>, @inout Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>) -> @error Error {
-bb0(%0 : $Range<Int>, %1 : $Int, %2 : $@noescape @callee_guaranteed @substituted <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_1) -> (Bool, @error Error) for <(scalar: Unicode.Scalar, normData: Unicode._NormData), (scalar: Unicode.Scalar, normData: Unicode._NormData)>, %3 : $*Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>):
-  debug_value %0 : $Range<Int>, let, name "range", argno 1
-  %5 = alloc_stack $Range<Int>
-  store %0 to [trivial] %5 : $*Range<Int>
-  debug_value %1 : $Int, let, name "sortedEnd", argno 2
-  %8 = alloc_stack $Int
-  store %1 to [trivial] %8 : $*Int
-  debug_value %5 : $*Range<Int>, let, name "range", argno 1, expr op_deref
-  debug_value %8 : $*Int, let, name "sortedEnd", argno 2, expr op_deref
-  debug_value %2 : $@noescape @callee_guaranteed @substituted <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_1) -> (Bool, @error Error) for <(scalar: Unicode.Scalar, normData: Unicode._NormData), (scalar: Unicode.Scalar, normData: Unicode._NormData)>, let, name "areInIncreasingOrder", argno 3
-  debug_value %3 : $*Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>, var, name "self", argno 4, implicit, expr op_deref
-  debug_value undef : $Error, var, name "$error", argno 5
-  %15 = alloc_stack $Int, var, name "sortedEnd"
-  copy_addr %8 to [init] %15 : $*Int
-  br bb1
-
-bb1:
-  %18 = alloc_stack $Int
-  copy_addr %15 to [init] %18 : $*Int
-  %20 = struct_element_addr %5 : $*Range<Int>, #Range.upperBound
-  %21 = alloc_stack $Int
-  copy_addr %20 to [init] %21 : $*Int
-  %23 = metatype $@thick Int.Type
-  %24 = witness_method $Int, #Equatable."==" : <Self where Self : Equatable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %25 = apply %24<Int>(%18, %21, %23) : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %26 = struct_extract %25 : $Bool, #Bool._value
-  %27 = integer_literal $Builtin.Int1, -1
-  %28 = builtin "xor_Int1"(%26 : $Builtin.Int1, %27 : $Builtin.Int1) : $Builtin.Int1
-  destroy_addr %21 : $*Int
-  dealloc_stack %21 : $*Int
-  destroy_addr %18 : $*Int
-  dealloc_stack %18 : $*Int
-  cond_br %28, bb2, bb3
-
-bb2:
-  %34 = alloc_stack $Int, var, name "i"
-  copy_addr %15 to [init] %34 : $*Int
-  br bb4
-
-bb3:
-  destroy_addr %15 : $*Int
-  dealloc_stack %15 : $*Int
-  %39 = tuple ()
-  dealloc_stack %8 : $*Int
-  dealloc_stack %5 : $*Range<Int>
-  return %39 : $()
-
-bb4:
-  %43 = alloc_stack $Int, let, name "j"
-  %44 = witness_method $Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>, #BidirectionalCollection.index : <Self where Self : BidirectionalCollection> (Self) -> (Self.Index) -> Self.Index : $@convention(witness_method: BidirectionalCollection) <τ_0_0 where τ_0_0 : BidirectionalCollection> (@in_guaranteed τ_0_0.Index, @in_guaranteed τ_0_0) -> @out τ_0_0.Index
-  %45 = apply %44<Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>>(%43, %34, %3) : $@convention(witness_method: BidirectionalCollection) <τ_0_0 where τ_0_0 : BidirectionalCollection> (@in_guaranteed τ_0_0.Index, @in_guaranteed τ_0_0) -> @out τ_0_0.Index
-  %46 = witness_method $Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>, #Collection.subscript!read : <Self where Self : Collection> (Self) -> (Self.Index) -> () : $@yield_once @convention(witness_method: Collection) <τ_0_0 where τ_0_0 : Collection> (@in_guaranteed τ_0_0.Index, @in_guaranteed τ_0_0) -> @yields @in_guaranteed τ_0_0.Element
-  (%47, %48) = begin_apply %46<Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>>(%34, %3) : $@yield_once @convention(witness_method: Collection) <τ_0_0 where τ_0_0 : Collection> (@in_guaranteed τ_0_0.Index, @in_guaranteed τ_0_0) -> @yields @in_guaranteed τ_0_0.Element
-  %49 = alloc_stack $(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  copy_addr %47 to [init] %49 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  end_apply %48
-  %52 = witness_method $Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>, #Collection.subscript!read : <Self where Self : Collection> (Self) -> (Self.Index) -> () : $@yield_once @convention(witness_method: Collection) <τ_0_0 where τ_0_0 : Collection> (@in_guaranteed τ_0_0.Index, @in_guaranteed τ_0_0) -> @yields @in_guaranteed τ_0_0.Element
-  (%53, %54) = begin_apply %52<Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>>(%43, %3) : $@yield_once @convention(witness_method: Collection) <τ_0_0 where τ_0_0 : Collection> (@in_guaranteed τ_0_0.Index, @in_guaranteed τ_0_0) -> @yields @in_guaranteed τ_0_0.Element
-  %55 = alloc_stack $(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  copy_addr %53 to [init] %55 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  end_apply %54
-  try_apply %2(%49, %55) : $@noescape @callee_guaranteed @substituted <τ_0_0, τ_0_1> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_1) -> (Bool, @error Error) for <(scalar: Unicode.Scalar, normData: Unicode._NormData), (scalar: Unicode.Scalar, normData: Unicode._NormData)>, normal bb5, error bb6
-
-bb5(%59 : $Bool):
-  destroy_addr %55 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  dealloc_stack %55 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  destroy_addr %49 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  dealloc_stack %49 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  %64 = struct_extract %59 : $Bool, #Bool._value
-  %65 = integer_literal $Builtin.Int1, -1
-  %66 = builtin "xor_Int1"(%64 : $Builtin.Int1, %65 : $Builtin.Int1) : $Builtin.Int1
-  cond_br %66, bb7, bb8
-
-bb6(%68 : @owned $Error):
-  destroy_addr %55 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  dealloc_stack %55 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  destroy_addr %49 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  dealloc_stack %49 : $*(scalar: Unicode.Scalar, normData: Unicode._NormData)
-  destroy_addr %43 : $*Int
-  dealloc_stack %43 : $*Int
-  destroy_addr %34 : $*Int
-  dealloc_stack %34 : $*Int
-  destroy_addr %15 : $*Int
-  dealloc_stack %15 : $*Int
-  dealloc_stack %8 : $*Int
-  dealloc_stack %5 : $*Range<Int>
-  throw %68 : $Error
-
-bb7:
-  destroy_addr %43 : $*Int
-  dealloc_stack %43 : $*Int
-  br bb9
-
-bb8:
-  %85 = witness_method $Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>, #MutableCollection.swapAt : <Self where Self : MutableCollection> (inout Self) -> (Self.Index, Self.Index) -> () : $@convention(witness_method: MutableCollection) <τ_0_0 where τ_0_0 : MutableCollection> (@in_guaranteed τ_0_0.Index, @in_guaranteed τ_0_0.Index, @inout τ_0_0) -> ()
-  %86 = apply %85<Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>>(%34, %43, %3) : $@convention(witness_method: MutableCollection) <τ_0_0 where τ_0_0 : MutableCollection> (@in_guaranteed τ_0_0.Index, @in_guaranteed τ_0_0.Index, @inout τ_0_0) -> ()
-  copy_addr %43 to %34 : $*Int
-  destroy_addr %43 : $*Int
-  dealloc_stack %43 : $*Int
-  %90 = alloc_stack $Int
-  copy_addr %34 to [init] %90 : $*Int
-  %92 = struct_element_addr %5 : $*Range<Int>, #Range.lowerBound
-  %93 = alloc_stack $Int
-  copy_addr %92 to [init] %93 : $*Int
-  %95 = metatype $@thick Int.Type
-  %96 = witness_method $Int, #Equatable."==" : <Self where Self : Equatable> (Self.Type) -> (Self, Self) -> Bool : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %97 = apply %96<Int>(%90, %93, %95) : $@convention(witness_method: Equatable) <τ_0_0 where τ_0_0 : Equatable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0, @thick τ_0_0.Type) -> Bool
-  %98 = struct_extract %97 : $Bool, #Bool._value
-  %99 = integer_literal $Builtin.Int1, -1
-  %100 = builtin "xor_Int1"(%98 : $Builtin.Int1, %99 : $Builtin.Int1) : $Builtin.Int1
-  destroy_addr %93 : $*Int
-  dealloc_stack %93 : $*Int
-  destroy_addr %90 : $*Int
-  dealloc_stack %90 : $*Int
-  cond_br %100, bb10, bb11
-
-bb9:
-  %106 = witness_method $Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>, #Collection.formIndex : <Self where Self : Collection> (Self) -> (inout Self.Index) -> () : $@convention(witness_method: Collection) <τ_0_0 where τ_0_0 : Collection> (@inout τ_0_0.Index, @in_guaranteed τ_0_0) -> ()
-  %107 = apply %106<Array<(scalar: Unicode.Scalar, normData: Unicode._NormData)>>(%15, %3) : $@convention(witness_method: Collection) <τ_0_0 where τ_0_0 : Collection> (@inout τ_0_0.Index, @in_guaranteed τ_0_0) -> ()
-  destroy_addr %34 : $*Int
-  dealloc_stack %34 : $*Int
-  br bb1
-
-bb10:
-  br bb4
-
-bb11:
-  br bb9
-}
-
-// CHECK-LABEL: sil [ossa] @$sSD5IndexV8_asCocoas02__C10DictionaryVAAVvM : {{.*}} {
-// CHECK-LABEL: } // end sil function '$sSD5IndexV8_asCocoas02__C10DictionaryVAAVvM'
-sil [ossa] @$sSD5IndexV8_asCocoas02__C10DictionaryVAAVvM : $@yield_once @convention(method) <Key, Value where Key : Hashable> (@inout Dictionary<Key, Value>.Index) -> @yields @inout __CocoaDictionary.Index {
-bb0(%0 : $*Dictionary<Key, Value>.Index):
-  debug_value %0 : $*Dictionary<Key, Value>.Index, var, name "self", argno 1, implicit, expr op_deref
-  %2 = alloc_stack $__CocoaDictionary.Index, var, name "cocoa"
-  %3 = struct_element_addr %0 : $*Dictionary<Key, Value>.Index, #Dictionary.Index._variant
-  %4 = load [copy] %3 : $*Dictionary<Key, Value>.Index._Variant
-  switch_enum %4 : $Dictionary<Key, Value>.Index._Variant, case #Dictionary.Index._Variant.cocoa!enumelt: bb1, case #Dictionary.Index._Variant.native!enumelt: bb3
-
-bb1(%6 : @owned $__CocoaDictionary.Index):
-  store %6 to [init] %2 : $*__CocoaDictionary.Index
-  %8 = integer_literal $Builtin.Int64, 0
-  %9 = struct $Int (%8 : $Builtin.Int64)
-  %10 = struct $_HashTable.Bucket (%9 : $Int)
-  %11 = integer_literal $Builtin.Int32, 0
-  %12 = struct $Int32 (%11 : $Builtin.Int32)
-  debug_value %12 : $Int32, let, name "age", argno 2
-  %14 = struct $_HashTable.Index (%10 : $_HashTable.Bucket, %12 : $Int32)
-  debug_value %14 : $_HashTable.Index, let, name "dummy"
-  %16 = enum $Dictionary<Key, Value>.Index._Variant, #Dictionary.Index._Variant.native!enumelt, %14 : $_HashTable.Index
-  %17 = struct $Dictionary<Key, Value>.Index (%16 : $Dictionary<Key, Value>.Index._Variant)
-  store %17 to [assign] %0 : $*Dictionary<Key, Value>.Index
-  yield %2 : $*__CocoaDictionary.Index, resume bb2, unwind bb9
-
-bb2:
-  debug_value %0 : $*Dictionary<Key, Value>.Index, var, name "self", argno 1, implicit, expr op_deref
-  %21 = load [copy] %2 : $*__CocoaDictionary.Index
-  %22 = enum $Dictionary<Key, Value>.Index._Variant, #Dictionary.Index._Variant.cocoa!enumelt, %21 : $__CocoaDictionary.Index
-  %23 = struct $Dictionary<Key, Value>.Index (%22 : $Dictionary<Key, Value>.Index._Variant)
-  store %23 to [assign] %0 : $*Dictionary<Key, Value>.Index
-  %25 = tuple ()
-  %26 = load [take] %2 : $*__CocoaDictionary.Index
-  destroy_value %26 : $__CocoaDictionary.Index
-  dealloc_stack %2 : $*__CocoaDictionary.Index
-  %29 = tuple ()
-  return %29 : $()
-
-bb3(%31 : $_HashTable.Index):
-  dealloc_stack %2 : $*__CocoaDictionary.Index
-  %33 = string_literal utf8 "Attempting to access Dictionary elements using an invalid index"
-  %34 = integer_literal $Builtin.Word, 63
-  %35 = builtin "ptrtoint_Word"(%33 : $Builtin.RawPointer) : $Builtin.Word
-  %36 = integer_literal $Builtin.Int8, 2
-  %37 = struct $StaticString (%35 : $Builtin.Word, %34 : $Builtin.Word, %36 : $Builtin.Int8)
-  %38 = string_literal utf8 "Swift/Dictionary.swift"
-  %39 = integer_literal $Builtin.Word, 22
-  %40 = builtin "ptrtoint_Word"(%38 : $Builtin.RawPointer) : $Builtin.Word
-  %41 = integer_literal $Builtin.Int8, 2
-  %42 = struct $StaticString (%40 : $Builtin.Word, %39 : $Builtin.Word, %41 : $Builtin.Int8)
-  %43 = integer_literal $Builtin.Int64, 1843
-  %44 = struct $UInt (%43 : $Builtin.Int64)
-  %45 = builtin "assert_configuration"() : $Builtin.Int32
-  %46 = integer_literal $Builtin.Int32, 0
-  %47 = builtin "cmp_eq_Int32"(%45 : $Builtin.Int32, %46 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %47, bb5, bb4
-
-bb4:
-  %49 = builtin "assert_configuration"() : $Builtin.Int32
-  %50 = integer_literal $Builtin.Int32, 1
-  %51 = builtin "cmp_eq_Int32"(%49 : $Builtin.Int32, %50 : $Builtin.Int32) : $Builtin.Int1
-  cond_fail %51 : $Builtin.Int1, "Attempting to access Dictionary elements using an invalid index"
-  %53 = builtin "conditionallyUnreachable"() : $Never
-  unreachable
-
-bb5:
-  %55 = string_literal utf8 "Fatal error"
-  %56 = integer_literal $Builtin.Word, 11
-  %57 = builtin "ptrtoint_Word"(%55 : $Builtin.RawPointer) : $Builtin.Word
-  %58 = integer_literal $Builtin.Int8, 2
-  %59 = struct $StaticString (%57 : $Builtin.Word, %56 : $Builtin.Word, %58 : $Builtin.Int8)
-  %60 = builtin "assert_configuration"() : $Builtin.Int32
-  %61 = integer_literal $Builtin.Int32, 0
-  %62 = builtin "cmp_eq_Int32"(%60 : $Builtin.Int32, %61 : $Builtin.Int32) : $Builtin.Int1
-  cond_br %62, bb6, bb7
-
-bb6:
-  %64 = integer_literal $Builtin.Int32, 1
-  %65 = struct $UInt32 (%64 : $Builtin.Int32)
-  br bb8(%65 : $UInt32)
-
-bb7:
-  %67 = integer_literal $Builtin.Int32, 0
-  %68 = struct $UInt32 (%67 : $Builtin.Int32)
-  br bb8(%68 : $UInt32)
-
-bb8(%70 : $UInt32):
-  %71 = function_ref @$ss17_assertionFailure__4file4line5flagss5NeverOs12StaticStringV_A2HSus6UInt32VtF : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  %72 = apply %71(%59, %37, %42, %44, %70) : $@convention(thin) (StaticString, StaticString, StaticString, UInt, UInt32) -> Never
-  unreachable
-
-bb9:
-  debug_value %0 : $*Dictionary<Key, Value>.Index, var, name "self", argno 1, implicit, expr op_deref
-  %75 = load [copy] %2 : $*__CocoaDictionary.Index
-  %76 = enum $Dictionary<Key, Value>.Index._Variant, #Dictionary.Index._Variant.cocoa!enumelt, %75 : $__CocoaDictionary.Index
-  %77 = struct $Dictionary<Key, Value>.Index (%76 : $Dictionary<Key, Value>.Index._Variant)
-  store %77 to [assign] %0 : $*Dictionary<Key, Value>.Index
-  %79 = tuple ()
-  %80 = load [take] %2 : $*__CocoaDictionary.Index
-  destroy_value %80 : $__CocoaDictionary.Index
-  dealloc_stack %2 : $*__CocoaDictionary.Index
-  unwind
-}
-
-// CHECK-LABEL: sil [ossa] @$ss48_UnsafePartiallyInitializedContiguousArrayBufferV3addyyxFs7UnicodeO6ScalarV_Tg5 : {{.*}} {
-// CHECK-LABEL: } // end sil function '$ss48_UnsafePartiallyInitializedContiguousArrayBufferV3addyyxFs7UnicodeO6ScalarV_Tg5'
-sil [ossa] @$ss48_UnsafePartiallyInitializedContiguousArrayBufferV3addyyxFs7UnicodeO6ScalarV_Tg5 : $@convention(method) (Unicode.Scalar, @inout _UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>) -> () {
-bb0(%0 : $Unicode.Scalar, %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>):
-  debug_value %0 : $Unicode.Scalar, let, name "element", argno 1
-  %3 = alloc_stack $Unicode.Scalar
-  store %0 to [trivial] %3 : $*Unicode.Scalar
-  debug_value %3 : $*Unicode.Scalar, let, name "element", argno 1, expr op_deref
-  debug_value %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, var, name "self", argno 2, implicit, expr op_deref
-  %7 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.remainingCapacity
-  %8 = load [trivial] %7 : $*Int
-  %9 = integer_literal $Builtin.Int64, 0
-  %10 = struct_extract %8 : $Int, #Int._value
-  %11 = builtin "cmp_eq_Int64"(%10 : $Builtin.Int64, %9 : $Builtin.Int64) : $Builtin.Int1
-  cond_br %11, bb1, bb2
-
-bb1:
-  %13 = alloc_stack $Int
-  %14 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.result
-  %15 = load_borrow %14 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %16 = function_ref @$ss22_ContiguousArrayBufferV8capacitySivg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  %17 = apply %16<Unicode.Scalar>(%15) : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  end_borrow %15 : $_ContiguousArrayBuffer<Unicode.Scalar>
-  %19 = function_ref @$ss18_growArrayCapacityyS2iF : $@convention(thin) (Int) -> Int
-  %20 = apply %19(%17) : $@convention(thin) (Int) -> Int
-  %21 = alloc_stack $Int
-  store %20 to [trivial] %21 : $*Int
-  %23 = integer_literal $Builtin.Int64, 1
-  %24 = struct $Int (%23 : $Builtin.Int64)
-  %25 = alloc_stack $Int
-  store %24 to [trivial] %25 : $*Int
-  %27 = function_ref @$ss3maxyxx_xtSLRzlF : $@convention(thin) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0) -> @out τ_0_0
-  %28 = apply %27<Int>(%13, %21, %25) : $@convention(thin) <τ_0_0 where τ_0_0 : Comparable> (@in_guaranteed τ_0_0, @in_guaranteed τ_0_0) -> @out τ_0_0
-  dealloc_stack %25 : $*Int
-  dealloc_stack %21 : $*Int
-  %31 = load [trivial] %13 : $*Int
-  debug_value %31 : $Int, let, name "newCapacity"
-  dealloc_stack %13 : $*Int
-  %34 = alloc_stack $_ContiguousArrayBuffer<Unicode.Scalar>, var, name "newResult"
-  %35 = metatype $@thin _ContiguousArrayBuffer<Unicode.Scalar>.Type
-  %36 = integer_literal $Builtin.Int64, 0
-  %37 = struct $Int (%36 : $Builtin.Int64)
-  %38 = function_ref @$ss22_ContiguousArrayBufferV19_uninitializedCount15minimumCapacityAByxGSi_SitcfC : $@convention(method) <τ_0_0> (Int, Int, @thin _ContiguousArrayBuffer<τ_0_0>.Type) -> @owned _ContiguousArrayBuffer<τ_0_0>
-  %39 = apply %38<Unicode.Scalar>(%31, %37, %35) : $@convention(method) <τ_0_0> (Int, Int, @thin _ContiguousArrayBuffer<τ_0_0>.Type) -> @owned _ContiguousArrayBuffer<τ_0_0>
-  %40 = copy_value %39 : $_ContiguousArrayBuffer<Unicode.Scalar>
-  store %40 to [init] %34 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %42 = metatype $@thin UnsafeMutablePointer<Unicode.Scalar>.Type
-  %43 = function_ref @$ss22_ContiguousArrayBufferV19firstElementAddressSpyxGvg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
-  %44 = apply %43<Unicode.Scalar>(%39) : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
-  %45 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.result
-  %46 = load_borrow %45 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %47 = function_ref @$ss22_ContiguousArrayBufferV8capacitySivg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  %48 = apply %47<Unicode.Scalar>(%46) : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  end_borrow %46 : $_ContiguousArrayBuffer<Unicode.Scalar>
-  %50 = struct_extract %44 : $UnsafeMutablePointer<Unicode.Scalar>, #UnsafeMutablePointer._rawValue
-  %51 = struct_extract %48 : $Int, #Int._value
-  %52 = builtin "truncOrBitCast_Int64_Word"(%51 : $Builtin.Int64) : $Builtin.Word
-  %53 = metatype $@thick Unicode.Scalar.Type
-  %54 = pointer_to_address %50 : $Builtin.RawPointer to [strict] $*Unicode.Scalar
-  %55 = index_addr %54 : $*Unicode.Scalar, %52 : $Builtin.Word
-  %56 = address_to_pointer %55 : $*Unicode.Scalar to $Builtin.RawPointer
-  %57 = struct $UnsafeMutablePointer<Unicode.Scalar> (%56 : $Builtin.RawPointer)
-  %58 = tuple ()
-  %59 = tuple ()
-  %60 = tuple ()
-  %61 = tuple ()
-  %62 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.p
-  store %57 to [trivial] %62 : $*UnsafeMutablePointer<Unicode.Scalar>
-  %64 = function_ref @$ss22_ContiguousArrayBufferV8capacitySivg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  %65 = apply %64<Unicode.Scalar>(%39) : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  %66 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.result
-  %67 = load_borrow %66 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %68 = function_ref @$ss22_ContiguousArrayBufferV8capacitySivg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  %69 = apply %68<Unicode.Scalar>(%67) : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  end_borrow %67 : $_ContiguousArrayBuffer<Unicode.Scalar>
-  %71 = struct_extract %65 : $Int, #Int._value
-  %72 = struct_extract %69 : $Int, #Int._value
-  %73 = integer_literal $Builtin.Int1, -1
-  %74 = builtin "ssub_with_overflow_Int64"(%71 : $Builtin.Int64, %72 : $Builtin.Int64, %73 : $Builtin.Int1) : $(Builtin.Int64, Builtin.Int1)
-  (%75, %76) = destructure_tuple %74 : $(Builtin.Int64, Builtin.Int1)
-  br bb3
-
-bb2:
-  br bb8
-
-bb3:
-  br bb4
-
-bb4:
-  cond_fail %76 : $Builtin.Int1, "arithmetic overflow"
-  %81 = struct $Int (%75 : $Builtin.Int64)
-  %82 = tuple ()
-  %83 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.remainingCapacity
-  store %81 to [trivial] %83 : $*Int
-  %85 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.result
-  %86 = load_borrow %85 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %87 = alloc_stack $_ContiguousArrayBuffer<Unicode.Scalar>
-  %88 = store_borrow %86 to %87 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %89 = load_borrow %87 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %90 = alloc_stack $_ContiguousArrayBuffer<Unicode.Scalar>
-  %91 = store_borrow %89 to %90 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %92 = function_ref @$sSlsE7isEmptySbvg : $@convention(method) <τ_0_0 where τ_0_0 : Collection> (@in_guaranteed τ_0_0) -> Bool
-  %93 = apply %92<_ContiguousArrayBuffer<Unicode.Scalar>>(%90) : $@convention(method) <τ_0_0 where τ_0_0 : Collection> (@in_guaranteed τ_0_0) -> Bool
-  dealloc_stack %90 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  end_borrow %86 : $_ContiguousArrayBuffer<Unicode.Scalar>
-  %96 = struct_extract %93 : $Bool, #Bool._value
-  %97 = integer_literal $Builtin.Int1, -1
-  %98 = builtin "xor_Int1"(%96 : $Builtin.Int1, %97 : $Builtin.Int1) : $Builtin.Int1
-  end_borrow %89 : $_ContiguousArrayBuffer<Unicode.Scalar>
-  dealloc_stack %87 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  cond_br %98, bb5, bb6
-
-bb5:
-  %102 = function_ref @$ss22_ContiguousArrayBufferV19firstElementAddressSpyxGvg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
-  %103 = apply %102<Unicode.Scalar>(%39) : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
-  %104 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.result
-  %105 = load_borrow %104 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %106 = function_ref @$ss22_ContiguousArrayBufferV19firstElementAddressSpyxGvg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
-  %107 = apply %106<Unicode.Scalar>(%105) : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> UnsafeMutablePointer<τ_0_0>
-  end_borrow %105 : $_ContiguousArrayBuffer<Unicode.Scalar>
-  %109 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.result
-  %110 = load_borrow %109 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %111 = function_ref @$ss22_ContiguousArrayBufferV8capacitySivg : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  %112 = apply %111<Unicode.Scalar>(%110) : $@convention(method) <τ_0_0> (@guaranteed _ContiguousArrayBuffer<τ_0_0>) -> Int
-  end_borrow %110 : $_ContiguousArrayBuffer<Unicode.Scalar>
-  %114 = function_ref @$sSp14moveInitialize4from5countySpyxG_SitF : $@convention(method) <τ_0_0> (UnsafeMutablePointer<τ_0_0>, Int, UnsafeMutablePointer<τ_0_0>) -> ()
-  %115 = apply %114<Unicode.Scalar>(%107, %112, %103) : $@convention(method) <τ_0_0> (UnsafeMutablePointer<τ_0_0>, Int, UnsafeMutablePointer<τ_0_0>) -> ()
-  %116 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.result
-  %117 = load_borrow %116 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %118 = integer_literal $Builtin.Int64, 0
-  %119 = struct $Int (%118 : $Builtin.Int64)
-  %120 = function_ref @$ss22_ContiguousArrayBufferV12mutableCountSivs : $@convention(method) <τ_0_0> (Int, @guaranteed _ContiguousArrayBuffer<τ_0_0>) -> ()
-  %121 = apply %120<Unicode.Scalar>(%119, %117) : $@convention(method) <τ_0_0> (Int, @guaranteed _ContiguousArrayBuffer<τ_0_0>) -> ()
-  end_borrow %117 : $_ContiguousArrayBuffer<Unicode.Scalar>
-  br bb7
-
-bb6:
-  br bb7
-
-bb7:
-  %125 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.result
-  %126 = load [copy] %125 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  %127 = struct_element_addr %1 : $*_UnsafePartiallyInitializedContiguousArrayBuffer<Unicode.Scalar>, #_UnsafePartiallyInitializedContiguousArrayBuffer.result
-  store %39 to [assign] %127 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  destroy_addr %34 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  store %126 to [init] %34 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  destroy_addr %34 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  dealloc_stack %34 : $*_ContiguousArrayBuffer<Unicode.Scalar>
-  br bb8
-
-bb8:
-  %133 = function_ref @$ss48_UnsafePartiallyInitializedContiguousArrayBufferV23addWithExistingCapacityyyxF : $@convention(method) <τ_0_0> (@in_guaranteed τ_0_0, @inout _UnsafePartiallyInitializedContiguousArrayBuffer<τ_0_0>) -> ()
-  %134 = apply %133<Unicode.Scalar>(%3, %1) : $@convention(method) <τ_0_0> (@in_guaranteed τ_0_0, @inout _UnsafePartiallyInitializedContiguousArrayBuffer<τ_0_0>) -> ()
-  %135 = tuple ()
-  dealloc_stack %3 : $*Unicode.Scalar
-  return %135 : $()
-}
-
-// CHECK-LABEL: sil [ossa] @$s10Foundation4DataV15_RepresentationOys5UInt8VSicis : {{.*}} {
-// CHECK-LABEL: } // end sil function '$s10Foundation4DataV15_RepresentationOys5UInt8VSicis'
-sil [ossa] @$s10Foundation4DataV15_RepresentationOys5UInt8VSicis : $@convention(method) (UInt8, Int, @inout Data._Representation) -> () {
-bb0(%0 : $UInt8, %1 : $Int, %2 : $*Data._Representation):
-  debug_value %0 : $UInt8, let, name "newValue", argno 1
-  debug_value %1 : $Int, let, name "index", argno 2, implicit
-  debug_value %2 : $*Data._Representation, var, name "self", argno 3, implicit, expr op_deref
-  %6 = load [copy] %2 : $*Data._Representation
-  switch_enum %6 : $Data._Representation, case #Data._Representation.empty!enumelt: bb1, case #Data._Representation.inline!enumelt: bb5, case #Data._Representation.slice!enumelt: bb6, case #Data._Representation.large!enumelt: bb7
-
-bb1:
-  br bb2
-
-bb2:
-  br bb3
-
-bb3:
-  br bb4
-
-bb4:
-  %11 = integer_literal $Builtin.Int1, -1
-  cond_fail %11 : $Builtin.Int1, "precondition failure"
-  unreachable
-
-bb5(%14 : $Data.InlineData):
-  %15 = alloc_stack [lexical] $Data.InlineData, var, name "inline"
-  store %14 to [trivial] %15 : $*Data.InlineData
-  debug_value %15 : $*Data.InlineData, var, name "inline", expr op_deref
-  %18 = function_ref @$s10Foundation4DataV06InlineB0Vys5UInt8VSicis : $@convention(method) (UInt8, Int, @inout Data.InlineData) -> ()
-  %19 = apply %18(%0, %1, %15) : $@convention(method) (UInt8, Int, @inout Data.InlineData) -> ()
-  %20 = metatype $@thin Data._Representation.Type
-  %21 = load [trivial] %15 : $*Data.InlineData
-  %22 = enum $Data._Representation, #Data._Representation.inline!enumelt, %21 : $Data.InlineData
-  store %22 to [assign] %2 : $*Data._Representation
-  dealloc_stack %15 : $*Data.InlineData
-  br bb8
-
-bb6(%26 : @owned $Data.InlineSlice):
-  %27 = alloc_stack [lexical] $Data.InlineSlice, var, name "slice"
-  store %26 to [init] %27 : $*Data.InlineSlice
-  debug_value %27 : $*Data.InlineSlice, var, name "slice", expr op_deref
-  %30 = metatype $@thin Data._Representation.Type
-  %31 = enum $Data._Representation, #Data._Representation.empty!enumelt
-  store %31 to [assign] %2 : $*Data._Representation
-  %33 = function_ref @$s10Foundation4DataV11InlineSliceVys5UInt8VSicis : $@convention(method) (UInt8, Int, @inout Data.InlineSlice) -> ()
-  %34 = apply %33(%0, %1, %27) : $@convention(method) (UInt8, Int, @inout Data.InlineSlice) -> ()
-  %35 = metatype $@thin Data._Representation.Type
-  %36 = load [copy] %27 : $*Data.InlineSlice
-  %37 = enum $Data._Representation, #Data._Representation.slice!enumelt, %36 : $Data.InlineSlice
-  store %37 to [assign] %2 : $*Data._Representation
-  destroy_addr %27 : $*Data.InlineSlice
-  dealloc_stack %27 : $*Data.InlineSlice
-  br bb8
-
-bb7(%42 : @owned $Data.LargeSlice):
-  %43 = alloc_stack [lexical] $Data.LargeSlice, var, name "slice"
-  store %42 to [init] %43 : $*Data.LargeSlice
-  debug_value %43 : $*Data.LargeSlice, var, name "slice", expr op_deref
-  %46 = metatype $@thin Data._Representation.Type
-  %47 = enum $Data._Representation, #Data._Representation.empty!enumelt
-  store %47 to [assign] %2 : $*Data._Representation
-  %49 = function_ref @$s10Foundation4DataV10LargeSliceVys5UInt8VSicis : $@convention(method) (UInt8, Int, @inout Data.LargeSlice) -> ()
-  %50 = apply %49(%0, %1, %43) : $@convention(method) (UInt8, Int, @inout Data.LargeSlice) -> ()
-  %51 = metatype $@thin Data._Representation.Type
-  %52 = load [copy] %43 : $*Data.LargeSlice
-  %53 = enum $Data._Representation, #Data._Representation.large!enumelt, %52 : $Data.LargeSlice
-  store %53 to [assign] %2 : $*Data._Representation
-  destroy_addr %43 : $*Data.LargeSlice
-  dealloc_stack %43 : $*Data.LargeSlice
-  br bb8
-
-bb8:
-  %58 = tuple ()
-  return %58 : $()
-}
diff --git a/validation-test/SILOptimizer/large_nested_array.swift.gyb b/validation-test/SILOptimizer/large_nested_array.swift.gyb
index 36af47f191e32..61b9a5c53f354 100644
--- a/validation-test/SILOptimizer/large_nested_array.swift.gyb
+++ b/validation-test/SILOptimizer/large_nested_array.swift.gyb
@@ -2,15 +2,15 @@
 // RUN: %gyb %s > %t/main.swift
 
 // The compiler should finish in less than 2 minutes. To give some slack,
-// specify a timeout of 12 minutes.
+// specify a timeout of 20 minutes.
 
 // TODO: 75% of compile time is spent in ARCSequenceOpts: rdar://144863155
 // The timeout should be decreased once we can get rid of ARCSequenceOpts
 
-// If the compiler needs more than 12 minutes, there is probably a real problem.
+// If the compiler needs more than 20 minutes, there is probably a real problem.
 // So please don't just increase the timeout in case this fails.
 
-// RUN: %{python} %S/../../test/Inputs/timeout.py 720 %target-swift-frontend -O -parse-as-library -sil-verify-none -c %t/main.swift -o %t/main.o
+// RUN: %{python} %S/../../test/Inputs/timeout.py 1200 %target-swift-frontend -O -parse-as-library -sil-verify-none -c %t/main.swift -o %t/main.o
 
 // REQUIRES: swift_stdlib_no_asserts,optimized_stdlib
 // REQUIRES: long_test
diff --git a/validation-test/SILOptimizer/ossa_lifetime_completion_crash.sil b/validation-test/SILOptimizer/ossa_lifetime_completion_crash.sil
new file mode 100644
index 0000000000000..17d0cf1ceb000
--- /dev/null
+++ b/validation-test/SILOptimizer/ossa_lifetime_completion_crash.sil
@@ -0,0 +1,33 @@
+// RUN: %empty-directory(%t)
+// RUN: not --crash %target-sil-opt -sil-print-types \
+// RUN:     -test-runner                             \
+// RUN:     %s                                       \
+// RUN:     -sil-disable-input-verify                \
+// RUN:     -o /dev/null                             \
+// RUN: 2>&1 | tee %t/out
+// RUN: %FileCheck %s < %t/out
+
+
+
+class C {}
+
+// CHECK: Invalid SIL provided to OSSACompleteLifetime?!
+// CHECK: OSSACompleteLifetime is visiting the availability boundary of %0 = argument of bb0 : $C
+// CHECK: When walking forward from the def to the availability boundary a non-dead-end successor-less block was encountered: bb0
+// CHECK: Its terminator must be an unreachable but is actually instead   return undef : $()                              // id: %1
+// CHECK: The walk stops at consumes, so reaching such a block means the value was leaked.  The function with the leak is as follows:
+// CHECK: sil [ossa] @leak_c : $@convention(thin) (@owned C) -> () {
+// CHECK: bb0(%0 : @owned $C):
+// CHECK:   return undef : $()
+// CHECK: } // end sil function 'leak_c'
+// CHECK: Invalid SIL provided to OSSACompleteLifetime?!
+// CHECK: Something that ran before OSSACompleteLifetime (the current pass, an earlier pass, SILGen) has introduced a leak of this value.
+// CHECK: Please rerun the crashing swift-frontend command with the following flags added and file a bug with the output:
+// CHECK: -sil-ownership-verify-all -Xllvm '-sil-print-function=leak_c' -Xllvm -sil-print-types -Xllvm -sil-print-module-on-error
+// CHECK: Use the -disable-sil-ownership-verifier frontend flag to disable this check.
+// CHECK: Invalid lifetime of value whose availability boundary is being visited.
+sil [ossa] @leak_c : $@convention(thin) (@owned C) -> () {
+entry(%c : @owned $C):
+  specify_test "ossa_complete_lifetime @argument availability"
+  return undef : $()
+}
diff --git a/validation-test/SILOptimizer/ossa_lifetime_completion_no_crash.sil b/validation-test/SILOptimizer/ossa_lifetime_completion_no_crash.sil
new file mode 100644
index 0000000000000..eba785e4210ee
--- /dev/null
+++ b/validation-test/SILOptimizer/ossa_lifetime_completion_no_crash.sil
@@ -0,0 +1,16 @@
+// RUN: %target-sil-opt -sil-print-types    \
+// RUN:     -test-runner                    \
+// RUN:     %s                              \
+// RUN:     -sil-disable-input-verify       \
+// RUN:     -disable-sil-ownership-verifier \
+// RUN:     -o /dev/null                    \
+// RUN: 2>&1 | %FileCheck %s
+
+class C {}
+
+// CHECK: end running test
+sil [ossa] @leak_c : $@convention(thin) (@owned C) -> () {
+entry(%c : @owned $C):
+  specify_test "ossa_complete_lifetime @argument availability"
+  return undef : $()
+}
diff --git a/validation-test/SILOptimizer/rdar133779160.swift b/validation-test/SILOptimizer/rdar133779160.swift
index 3fbf254602f35..cf61dd8911e26 100644
--- a/validation-test/SILOptimizer/rdar133779160.swift
+++ b/validation-test/SILOptimizer/rdar133779160.swift
@@ -1,6 +1,7 @@
 // RUN: %target-build-swift %s -sanitize=thread
 
 // REQUIRES: tsan_runtime
+// UNSUPPORTED: OS=ios && CPU=arm64e
 
 class C {}
 func passC(_ b: consuming C) {
diff --git a/validation-test/SILOptimizer/rdar139666145.swift b/validation-test/SILOptimizer/rdar139666145.swift
new file mode 100644
index 0000000000000..fb07277f2c5d0
--- /dev/null
+++ b/validation-test/SILOptimizer/rdar139666145.swift
@@ -0,0 +1,11 @@
+// RUN: %target-build-swift %s
+
+struct Box<T> { var value: T }
+
+func modify(_ string: inout String) {}
+
+func tryConsume() {
+    var box = Box(value: "")
+    modify(&box.value)
+    print(consume box)
+}
diff --git a/validation-test/SILOptimizer/rdar141279635.swift b/validation-test/SILOptimizer/rdar141279635.swift
new file mode 100644
index 0000000000000..68bde18019ae5
--- /dev/null
+++ b/validation-test/SILOptimizer/rdar141279635.swift
@@ -0,0 +1,21 @@
+// RUN: %target-build-swift %s
+
+protocol P: ~Copyable {
+    var property: Bool { get }
+    consuming func function()
+}
+
+struct S: P, ~Copyable {
+    var property: Bool { false }
+    consuming func function() {}
+}
+
+func g(s: consuming any P & ~Copyable) {
+    let s = s
+    s.function()
+}
+
+func f() {
+    let s = S()
+    g(s: s)
+}
diff --git a/validation-test/SILOptimizer/rdar151568816.swift b/validation-test/SILOptimizer/rdar151568816.swift
new file mode 100644
index 0000000000000..a7108553f05fc
--- /dev/null
+++ b/validation-test/SILOptimizer/rdar151568816.swift
@@ -0,0 +1,32 @@
+// RUN: %target-swift-frontend %s -enable-experimental-feature Lifetimes -emit-sil 
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
+
+// Ensure we don't crash
+
+struct Wrapper : ~Copyable {
+}
+
+struct NE : ~Escapable {
+  @_lifetime(borrow w)
+  init(_ w: borrowing Wrapper) {}
+}
+
+struct MyBox : ~Copyable {
+  public var value: NE {
+    _read { 
+      let w = Wrapper()
+      yield NE(w)
+    }
+  }
+}
+
+func use(_ n: borrowing NE) {}
+
+func foo() {
+  let box = MyBox()
+  let value = box.value
+  use(value)
+}
+
diff --git a/validation-test/SILOptimizer/rdar155059418.swift b/validation-test/SILOptimizer/rdar155059418.swift
new file mode 100644
index 0000000000000..7dce0041604ea
--- /dev/null
+++ b/validation-test/SILOptimizer/rdar155059418.swift
@@ -0,0 +1,21 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend %t/Library.swift -sil-verify-all -emit-sil -import-objc-header %t/Header.h > /dev/null
+
+// REQUIRES: objc_interop
+
+//--- Header.h
+
+@import Foundation;
+
+@interface Foo : NSObject
+@property (nonatomic, readwrite) NSUInteger length;
+@end
+
+//--- Library.swift
+
+func foo(_ x: borrowing Foo) -> UInt {
+    let y = x.length
+    return y
+}
+
diff --git a/validation-test/SILOptimizer/rdar159211502.swift b/validation-test/SILOptimizer/rdar159211502.swift
new file mode 100644
index 0000000000000..0cb0c97cd813c
--- /dev/null
+++ b/validation-test/SILOptimizer/rdar159211502.swift
@@ -0,0 +1,14 @@
+// RUN: %target-build-swift %s -O -Xfrontend -sil-verify-all
+
+protocol PA<I> {
+  associatedtype I: P
+  func get() -> I
+}
+
+protocol P {
+  var pa: any PA<Self> { get }
+}
+
+func f(_ p: any P) {
+  p.pa.get()
+}
diff --git a/validation-test/SILOptimizer/rdar160692694.swift b/validation-test/SILOptimizer/rdar160692694.swift
new file mode 100644
index 0000000000000..44dd332fe2e1e
--- /dev/null
+++ b/validation-test/SILOptimizer/rdar160692694.swift
@@ -0,0 +1,12 @@
+// RUN: %target-swift-frontend \
+// RUN:     -c \
+// RUN:     -verify \
+// RUN:     -disable-availability-checking \
+// RUN:     -swift-version 6 \
+// RUN:     %s
+
+typealias A = InlineArray<2, UInt64>
+func mix(_ a: inout A) {
+    swap(&a[0], &a[1]) // expected-error{{overlapping accesses}}
+                       // expected-note@-1{{conflicting access}}
+}
diff --git a/validation-test/SILOptimizer/rdar161371112.swift b/validation-test/SILOptimizer/rdar161371112.swift
new file mode 100644
index 0000000000000..87b3da4df0dcf
--- /dev/null
+++ b/validation-test/SILOptimizer/rdar161371112.swift
@@ -0,0 +1,56 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend \
+// RUN:     %t/Library.swift \
+// RUN:     -enable-experimental-feature Lifetimes \
+// RUN:     -sil-verify-all \
+// RUN:     -verify \
+// RUN:     -emit-sil \
+// RUN:     -import-objc-header %t/Header.h \
+// RUN: > /dev/null
+
+// REQUIRES: objc_interop
+
+// REQUIRES: swift_feature_Lifetimes
+
+//--- Header.h
+
+@import Foundation;
+
+@interface Foo : NSObject
+@property (nonatomic, readwrite) NSInteger length;
+- (const unichar *)_fastCharacterContents NS_RETURNS_INNER_POINTER;
+@end
+
+//--- Library.swift
+
+extension Foo {
+    var utf16Span: Span<UInt16>? {
+        @_lifetime(borrow self)
+        borrowing get {
+            // FIXME: This error shouldn't be here.
+            guard let ptr = self._fastCharacterContents() else { // expected-error{{copy of noncopyable typed value}}
+                return nil
+            }
+            let length = self.length
+            let buffer = UnsafeBufferPointer(start: ptr, count: length)
+            let span = unsafe Span<UInt16>(_unsafeElements: buffer)
+            return _overrideLifetime(span, borrowing: self)
+        }
+    }
+}
+
+extension NSString {
+    var utf16Span: Span<UInt16>? {
+        @_lifetime(borrow self)
+        borrowing get { // expected-error{{'self' is borrowed and cannot be consumed}}
+            guard let ptr = CFStringGetCharactersPtr(self) else { // expected-note{{consumed here}}
+                return nil
+            }
+            let length = self.length
+            let buffer = UnsafeBufferPointer(start: ptr, count: length)
+            let span = unsafe Span<UInt16>(_unsafeElements: buffer)
+            return _overrideLifetime(span, borrowing: self)
+        }
+    }
+}
diff --git a/validation-test/SILOptimizer/rdar161433604.swift b/validation-test/SILOptimizer/rdar161433604.swift
new file mode 100644
index 0000000000000..185b0e4c6ebd6
--- /dev/null
+++ b/validation-test/SILOptimizer/rdar161433604.swift
@@ -0,0 +1,25 @@
+// RUN: %target-swift-frontend \
+// RUN:     -disable-availability-checking \
+// RUN:     -target %target-swift-5.9-abi-triple \
+// RUN:     -emit-sil -verify \
+// RUN:     -enable-experimental-feature LifetimeDependence \
+// RUN:     -enable-experimental-feature Embedded \
+// RUN:     %s
+
+// REQUIRES: OS=macosx || OS=linux-gnu
+// REQUIRES: swift_feature_Embedded
+// REQUIRES: swift_feature_LifetimeDependence
+// REQUIRES: embedded_stdlib
+
+struct NoEscapeNoCopy: ~Escapable, ~Copyable {}
+
+protocol Foo {
+    var bar: NoEscapeNoCopy {get}
+}
+
+public struct Baz: Foo {
+    var bar: NoEscapeNoCopy {
+      NoEscapeNoCopy() // expected-error{{lifetime-dependent value escapes its scope}}
+                       // expected-note@-1{{it depends on the lifetime of this parent value}}
+    } // expected-note{{this use causes the lifetime-dependent value to escape}}
+}
diff --git a/validation-test/Sanitizers/tsan-inout.swift b/validation-test/Sanitizers/tsan-inout.swift
index 94b886da31236..1f4fd4903f19e 100644
--- a/validation-test/Sanitizers/tsan-inout.swift
+++ b/validation-test/Sanitizers/tsan-inout.swift
@@ -8,6 +8,12 @@
 // REQUIRES: stress_test
 // REQUIRES: tsan_runtime
 
+// Bug in TSan on FreeBSD
+// Thread destruction interceptor marks the thread ignored and then checks that
+// the thread isn't being ignored.
+// rdar://158450231
+// XFAIL: OS=freebsd
+
 // Test ThreadSanitizer execution end-to-end when calling
 // an uninstrumented module with inout parameters
 
@@ -27,7 +33,7 @@ var gInThread2: () -> () = { }
 // Spawn two threads, run the two passed in closures simultaneously, and
 // join them.
 func testRace(name: String, thread inThread1: @escaping () -> (), thread inThread2: @escaping () -> ()) {
-#if canImport(Darwin)
+#if canImport(Darwin) || os(FreeBSD)
   var thread1: pthread_t?
   var thread2: pthread_t?
 #else
diff --git a/validation-test/Sema/SwiftUI/rdar57201781.swift b/validation-test/Sema/SwiftUI/rdar57201781.swift
index 548bfc2ba68e3..2fedad32ed5ca 100644
--- a/validation-test/Sema/SwiftUI/rdar57201781.swift
+++ b/validation-test/Sema/SwiftUI/rdar57201781.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx10.15 -swift-version 5
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -target %target-cpu-apple-macosx10.15 -swift-version 5
 
 // REQUIRES: objc_interop
 // REQUIRES: OS=macosx
diff --git a/validation-test/Sema/SwiftUI/rdar57410798.swift b/validation-test/Sema/SwiftUI/rdar57410798.swift
index 9f2cc67f03889..e56889ce3816f 100644
--- a/validation-test/Sema/SwiftUI/rdar57410798.swift
+++ b/validation-test/Sema/SwiftUI/rdar57410798.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx10.15 -swift-version 5
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -target %target-cpu-apple-macosx10.15 -swift-version 5
 // REQUIRES: objc_interop
 // REQUIRES: OS=macosx
 
diff --git a/validation-test/Sema/SwiftUI/rdar74447308.swift b/validation-test/Sema/SwiftUI/rdar74447308.swift
index ee1601eb79e7b..d59653ac9070d 100644
--- a/validation-test/Sema/SwiftUI/rdar74447308.swift
+++ b/validation-test/Sema/SwiftUI/rdar74447308.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx10.15 -swift-version 5
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -target %target-cpu-apple-macosx10.15 -swift-version 5
 
 // REQUIRES: objc_interop
 // REQUIRES: OS=macosx
diff --git a/validation-test/Sema/SwiftUI/rdar76252310.swift b/validation-test/Sema/SwiftUI/rdar76252310.swift
index 397bca36bf613..39cbacc5099b0 100644
--- a/validation-test/Sema/SwiftUI/rdar76252310.swift
+++ b/validation-test/Sema/SwiftUI/rdar76252310.swift
@@ -41,13 +41,11 @@ func fromMainActor() async {
 func fromConcurrencyAware() async {
   let view = CoffeeTrackerView() // synthesized 'init' is 'nonisolated'
 
-  // expected-note@+3 {{property access is 'async'}}
-  // expected-warning@+2 {{non-sendable type 'some View' of property 'body' cannot exit main actor-isolated context}}
-  // expected-warning@+1 {{expression is 'async' but is not marked with 'await'}}
+  // expected-warning@+2 {{non-Sendable type 'some View' of property 'body' cannot exit main actor-isolated context}}
+  // expected-warning@+1 {{main actor-isolated property 'body' cannot be accessed from outside of the actor}} {{7-7=await }}
   _ = view.body
 
-  // expected-note@+2 {{property access is 'async'}}
-  // expected-warning@+1 {{expression is 'async' but is not marked with 'await'}}
+  // expected-warning@+1 {{main actor-isolated property 'showDrinkList' cannot be accessed from outside of the actor}} {{7-7=await }}
   _ = view.showDrinkList
 
   _ = view.storage
diff --git a/validation-test/Sema/SwiftUI/rdar84580119.swift b/validation-test/Sema/SwiftUI/rdar84580119.swift
index aa7b333acf8ce..20c0164e08c8a 100644
--- a/validation-test/Sema/SwiftUI/rdar84580119.swift
+++ b/validation-test/Sema/SwiftUI/rdar84580119.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx10.15 -swift-version 5
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -target %target-cpu-apple-macosx10.15 -swift-version 5
 // REQUIRES: objc_interop
 // REQUIRES: OS=macosx
 
diff --git a/validation-test/Sema/SwiftUI/rdar88256059.swift b/validation-test/Sema/SwiftUI/rdar88256059.swift
index 4ddbbe90603c5..bdb3a63d56439 100644
--- a/validation-test/Sema/SwiftUI/rdar88256059.swift
+++ b/validation-test/Sema/SwiftUI/rdar88256059.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx10.15 -swift-version 5
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -target %target-cpu-apple-macosx10.15 -swift-version 5
 // REQUIRES: objc_interop
 // REQUIRES: OS=macosx
 
@@ -9,7 +9,7 @@ struct MyView: View {
 
   var body: some View {
     Table(self.data) {
-      // expected-error@-1 {{expected expression in result builder 'TableColumnBuilder'}} {{23-23=<#result#>}}
+      // expected-error@-1 {{expected expression of type 'Columns' in result builder 'TableColumnBuilder'}} {{23-23=<#T##Columns#>}}
     }
   }
 }
diff --git a/validation-test/Sema/SwiftUI/swiftui_multiple_chained_members_in_inner_closure.swift b/validation-test/Sema/SwiftUI/swiftui_multiple_chained_members_in_inner_closure.swift
new file mode 100644
index 0000000000000..dbfc309569c85
--- /dev/null
+++ b/validation-test/Sema/SwiftUI/swiftui_multiple_chained_members_in_inner_closure.swift
@@ -0,0 +1,34 @@
+// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx12 -solver-scope-threshold=10000
+
+// REQUIRES: OS=macosx
+// REQUIRES: objc_interop
+
+import Foundation
+import SwiftUI
+
+struct MyView: View {
+    public enum Style {
+        case focusRing(platterSize: CGSize, stroke: CGFloat, offset: CGFloat)
+     }
+
+    var style: Style
+    var isFocused: Bool
+    var focusColor: Color
+
+    var body: some View {
+        Group {
+            switch style {
+            case let .focusRing(platterSize: platterSize, stroke: focusRingStroke, offset: focusRingOffset):
+                Circle()
+                  .overlay {
+                      Circle()
+                        .stroke(isFocused ? focusColor : Color.clear, lineWidth: focusRingStroke)
+                        .frame(
+                          width: platterSize.width + (2 * focusRingOffset) + focusRingStroke,
+                          height: platterSize.height + (2 * focusRingOffset) + focusRingStroke
+                        )
+                  }
+            }
+        }
+    }
+}
diff --git a/validation-test/Sema/custom_array_literal_with_operators.swift b/validation-test/Sema/custom_array_literal_with_operators.swift
new file mode 100644
index 0000000000000..dd064743356bc
--- /dev/null
+++ b/validation-test/Sema/custom_array_literal_with_operators.swift
@@ -0,0 +1,39 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol ScalarOrArray {
+}
+
+protocol SpecialValue: ScalarOrArray {
+}
+
+extension Array: ScalarOrArray where Element: SpecialValue {
+}
+
+struct CustomArray : ScalarOrArray {
+}
+
+extension CustomArray : ExpressibleByArrayLiteral {
+  public init(arrayLiteral elements: Int32...) {
+    self.init()
+  }
+}
+
+extension Int32: SpecialValue {
+}
+
+func +<T: ScalarOrArray>(_: T, _: CustomArray) -> CustomArray {}
+func +<T: ScalarOrArray>(_: CustomArray, _: T) -> CustomArray {}
+func +(_: CustomArray, _: CustomArray) -> CustomArray {}
+
+extension Sequence where Element == Int {
+  var asInt32: [Int32] { [] }
+}
+
+extension Array where Element == Int {
+  var asInt32: [Int32] { [] }
+}
+
+func test(v: Int32, b: [Int]) -> [Int32] {
+  let result = [1, v - v] + b.asInt32
+  return result // Ok
+}
diff --git a/validation-test/Sema/implicit_cgfloat_double_conversion_correctness.swift b/validation-test/Sema/implicit_cgfloat_double_conversion_correctness.swift
index 121812a279c67..9858e190a69bd 100644
--- a/validation-test/Sema/implicit_cgfloat_double_conversion_correctness.swift
+++ b/validation-test/Sema/implicit_cgfloat_double_conversion_correctness.swift
@@ -47,3 +47,16 @@ func test_atan_ambiguity(points: (CGPoint, CGPoint)) {
   test = atan((points.1.y - points.0.y) / (points.1.x - points.0.x)) // Ok
   _ = test
 }
+
+func test_ambigity_with_generic_funcs(a: CGFloat, b: CGFloat) -> [CGFloat] {
+  let result = [round(abs(a - b) * 100) / 100.0]
+  return result
+}
+
+func testMultipleClosureInference(_ d: Double, i: Int) {
+  struct S<T> {
+    init(_ get: () -> T, _ set: (T) -> Void) {}
+  }
+  func foo<T>(_: S<T>, _: T) {}
+  foo(S({ CGFloat(i) }, { _ in }), d)
+}
diff --git a/validation-test/Sema/protocol_typo_correction.swift b/validation-test/Sema/protocol_typo_correction.swift
index fef105a6189c2..5e7c13a3a089b 100644
--- a/validation-test/Sema/protocol_typo_correction.swift
+++ b/validation-test/Sema/protocol_typo_correction.swift
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -D LIB %s -o %t/Lib.swiftmodule
-// RUN: %target-swift-frontend -I %t -typecheck %s -verify
+// RUN: %target-swift-frontend -I %t -typecheck %s -verify -verify-ignore-unrelated
 // REQUIRES: objc_interop
 
 #if LIB
diff --git a/validation-test/Sema/rdar149385088.swift b/validation-test/Sema/rdar149385088.swift
new file mode 100644
index 0000000000000..f4cd8f537114e
--- /dev/null
+++ b/validation-test/Sema/rdar149385088.swift
@@ -0,0 +1,24 @@
+// RUN: %target-typecheck-verify-swift \
+// RUN:   -enable-experimental-feature Lifetimes \
+// RUN:   -enable-experimental-feature CoroutineAccessors
+
+// REQUIRES: swift_feature_Lifetimes
+// REQUIRES: swift_feature_CoroutineAccessors
+
+struct NE<T : ~Copyable & ~Escapable> : ~Copyable & ~Escapable {
+  @_lifetime(&t)
+  init(
+    t: inout T
+  )
+  {
+  }
+}
+
+struct S : ~Copyable & ~Escapable {
+  var mutableBytes: NE<S> {
+    @_lifetime(&self)
+    mutating get {
+      return NE(t: &self)
+    }
+  }
+}
diff --git a/validation-test/Sema/type_checker_crashers_fixed/issue-65360.swift b/validation-test/Sema/type_checker_crashers_fixed/issue-65360.swift
index fd6652a85f4e4..df4c4ead1c2bc 100644
--- a/validation-test/Sema/type_checker_crashers_fixed/issue-65360.swift
+++ b/validation-test/Sema/type_checker_crashers_fixed/issue-65360.swift
@@ -9,13 +9,13 @@ let _: () -> Void = {
 
 let _: () -> Void = {
   for case (0)? in [a] {}
-  // expected-error@-1 {{pattern cannot match values of type 'Any?'}}
+  // expected-error@-1 {{cannot convert sequence element type 'Any?' to expected type 'Int?'}}
   if case (0, 0) = a {}
 }
 
 let _: () -> Void = {
   for case (0)? in [a] {}
-  // expected-error@-1 {{pattern cannot match values of type 'Any?'}}
+  // expected-error@-1 {{cannot convert sequence element type 'Any?' to expected type 'Int?'}}
   for case (0, 0) in [a] {}
 }
 
diff --git a/validation-test/Sema/type_checker_crashers_fixed/issue-73454.swift b/validation-test/Sema/type_checker_crashers_fixed/issue-73454.swift
new file mode 100644
index 0000000000000..106a4fca89656
--- /dev/null
+++ b/validation-test/Sema/type_checker_crashers_fixed/issue-73454.swift
@@ -0,0 +1,21 @@
+// RUN: %target-typecheck-verify-swift
+
+// https://github.com/apple/swift/issues/73454
+
+func object_method_bind_ptrcall_v(
+  _: UnsafeMutableRawPointer?...
+) {
+}
+
+func setDensity(_ density: Double, ptr: UnsafeMutableRawPointer) {
+  var copy_density = density
+  var arr: [Int] = []
+
+  object_method_bind_ptrcall_v(&copy_density)
+  object_method_bind_ptrcall_v(&arr)
+
+  object_method_bind_ptrcall_v(&arr, &copy_density)
+
+  object_method_bind_ptrcall_v(ptr, &copy_density, &arr)
+  object_method_bind_ptrcall_v(&copy_density, ptr, &arr)
+}
diff --git a/validation-test/Sema/type_checker_crashers_fixed/rdar116122902.swift b/validation-test/Sema/type_checker_crashers_fixed/rdar116122902.swift
index f5f24dfe77b55..dcd66eaa3013d 100644
--- a/validation-test/Sema/type_checker_crashers_fixed/rdar116122902.swift
+++ b/validation-test/Sema/type_checker_crashers_fixed/rdar116122902.swift
@@ -14,9 +14,9 @@ struct Test {
 
   mutating func test<T>(v: Value<T>) {
     _ = {
-      // FIXME(diagnostics): We need to figure out how to avoid mentioning <<error type>> in the second diagnostic
+      // FIXME(diagnostics): This isn't a useful error message
       self.tuple = (v, 42)
-      // expected-error@-1 {{generic struct 'Value' requires the types 'T' and '<<error type>>' be equivalent}}
+      // expected-error@-1 {{generic struct 'Value' requires the types 'T' and '_' be equivalent}}
       return 0
     }
   }
diff --git a/validation-test/Sema/type_checker_crashers_fixed/rdar141012049.swift b/validation-test/Sema/type_checker_crashers_fixed/rdar141012049.swift
index 9c2f747ca9d2e..cd132c2afa4cb 100644
--- a/validation-test/Sema/type_checker_crashers_fixed/rdar141012049.swift
+++ b/validation-test/Sema/type_checker_crashers_fixed/rdar141012049.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 func test(_ v: [Int]) {
   let result = v.filter { }.flatMap(\.wrong) {
diff --git a/validation-test/Sema/type_checker_crashers_fixed/rdar143586718.swift b/validation-test/Sema/type_checker_crashers_fixed/rdar143586718.swift
new file mode 100644
index 0000000000000..15b63dafb67f3
--- /dev/null
+++ b/validation-test/Sema/type_checker_crashers_fixed/rdar143586718.swift
@@ -0,0 +1,6 @@
+// RUN: %target-typecheck-verify-swift -swift-version 6
+
+// rdar://143586718 - crash due to lookup not delayed on partially resolved base with Sendable requirements
+
+_ = { () -> Array? in .max }
+// expected-error@-1 {{unable to infer closure type without a type annotation}}
diff --git a/validation-test/Sema/type_checker_crashers_fixed/rdar151943924.swift b/validation-test/Sema/type_checker_crashers_fixed/rdar151943924.swift
new file mode 100644
index 0000000000000..6b0cde035d736
--- /dev/null
+++ b/validation-test/Sema/type_checker_crashers_fixed/rdar151943924.swift
@@ -0,0 +1,18 @@
+// RUN: %target-typecheck-verify-swift
+
+@propertyWrapper
+struct Weak<Value> {
+    var wrappedValue: Value? { fatalError() }
+}
+
+struct WeakStorage<Item: Hashable> {
+    @Weak var action: ((Set<Item>) -> Void)??
+}
+
+final class Test {
+    var storage: WeakStorage<AnyHashable> = .init()
+
+    func test(items: Set<AnyHashable>) {
+        storage.action??(items)
+    }
+}
diff --git a/validation-test/Sema/type_checker_crashers_fixed/rdar156955193.swift b/validation-test/Sema/type_checker_crashers_fixed/rdar156955193.swift
new file mode 100644
index 0000000000000..ecb0864ae802e
--- /dev/null
+++ b/validation-test/Sema/type_checker_crashers_fixed/rdar156955193.swift
@@ -0,0 +1,25 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol Definition {
+  associatedtype Delegate
+}
+
+enum Kind {
+  case normal
+  case other
+}
+
+struct Payload {
+}
+
+extension Definition where Delegate == ((Kind, Payload) -> Void) {
+  static func invokeDelegate(_ delegate: Delegate, kind: Kind, payload: Payload) {
+    delegate(kind, payload)
+  }
+}
+
+extension Definition where Delegate == ((Kind, Payload) -> Void)? {
+  static func invokeOptionalDelegate(_ delegate: Delegate, kind: Kind, payload: Payload) {
+    delegate?(kind, payload)
+  }
+}
diff --git a/validation-test/Sema/type_checker_crashers_fixed/rdar45470505.swift b/validation-test/Sema/type_checker_crashers_fixed/rdar45470505.swift
index c49d4f2ef18d3..bf3f88ac8ee0e 100644
--- a/validation-test/Sema/type_checker_crashers_fixed/rdar45470505.swift
+++ b/validation-test/Sema/type_checker_crashers_fixed/rdar45470505.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 extension BinaryInteger {
   init(bytes: [UInt8]) { fatalError() }
diff --git a/validation-test/Sema/type_checker_crashers_fixed/rdar50869732.swift b/validation-test/Sema/type_checker_crashers_fixed/rdar50869732.swift
index 753849a9fdb9d..b5f084757b57f 100644
--- a/validation-test/Sema/type_checker_crashers_fixed/rdar50869732.swift
+++ b/validation-test/Sema/type_checker_crashers_fixed/rdar50869732.swift
@@ -25,7 +25,7 @@ struct Empty {
   init() {}
 }
 
-struct Test<T> where T : P { // expected-note {{where 'T' = 'Generic<(Empty, _)>'}}
+struct Test<T> where T : P { // expected-note {{where 'T' = 'Generic<(Empty, C1)>'}}
   init(@Builder _: () -> T) {}
 }
 
@@ -34,5 +34,5 @@ let x = G {
   Test { Empty() }
   // expected-error@-1 {{static method 'buildBlock' requires that 'Empty' conform to 'P'}}
   // expected-error@-2 {{missing argument for parameter #2 in call}}
-  // expected-error@-3 {{generic struct 'Test' requires that 'Generic<(Empty, _)>' conform to 'P'}}
+  // expected-error@-3 {{generic struct 'Test' requires that 'Generic<(Empty, C1)>' conform to 'P'}}
 }
diff --git a/validation-test/Sema/type_checker_perf/fast/array_concatenation.swift b/validation-test/Sema/type_checker_perf/fast/array_concatenation.swift
index 1ce9d4293dc49..873889b4a20bd 100644
--- a/validation-test/Sema/type_checker_perf/fast/array_concatenation.swift
+++ b/validation-test/Sema/type_checker_perf/fast/array_concatenation.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-disable-shrink
+// RUN: %target-typecheck-verify-swift
 
 // Self-contained test case
 protocol P1 {}; func f<T: P1>(_: T, _: T) -> T { fatalError() }
diff --git a/validation-test/Sema/type_checker_perf/fast/array_literal_with_operators_and_double_literals.swift b/validation-test/Sema/type_checker_perf/fast/array_literal_with_operators_and_double_literals.swift
new file mode 100644
index 0000000000000..02c4727431584
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/array_literal_with_operators_and_double_literals.swift
@@ -0,0 +1,30 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck -solver-expression-time-threshold=1
+
+// REQUIRES: objc_interop
+
+// FIXME: This should be a scale-test but it doesn't allow passing `%clang-importer-sdk`
+
+// This import is important because it brings CGFloat and
+// enables Double<->CGFloat implicit conversion that affects
+// literals below.
+import Foundation
+
+let p/*: [(String, Bool, Bool, Double)]*/ = [
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0),
+  ("", true, true, 0 * 0.0 * 0.0)
+]
diff --git a/validation-test/Sema/type_checker_perf/fast/array_of_literals_and_operators_cast_to_float.swift.gyb b/validation-test/Sema/type_checker_perf/fast/array_of_literals_and_operators_cast_to_float.swift.gyb
new file mode 100644
index 0000000000000..2cd48795d50c5
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/array_of_literals_and_operators_cast_to_float.swift.gyb
@@ -0,0 +1,10 @@
+// RUN: %scale-test --begin 1 --end 10 --step 1 --select NumLeafScopes %s
+// REQUIRES: asserts,no_asan
+
+let _ = [
+  0,
+%for i in range(2, N+2):
+  1/${i},
+%end
+  1
+] as [Float]
diff --git a/validation-test/Sema/type_checker_perf/fast/borderline_flat_map_operator_mix.swift b/validation-test/Sema/type_checker_perf/fast/borderline_flat_map_operator_mix.swift
deleted file mode 100644
index cca07954da499..0000000000000
--- a/validation-test/Sema/type_checker_perf/fast/borderline_flat_map_operator_mix.swift
+++ /dev/null
@@ -1,21 +0,0 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=10
-
-// REQUIRES: no_asan
-
-struct S {
-    var t: Double
-
-    init(_ t: Double) {
-       self.t = t
-    }
-}
-
-func f(x: Array<S>, y: Range<Int>) -> [S] {
-    return x.flatMap { z in
-        return ((y.lowerBound / 1)...(y.upperBound + 1) / 1).flatMap { w in
-            return [S(1 * Double(w) + 1.0 + z.t),
-                    S(1 * Double(w) + 1.0 - z.t)]
-        }
-    }
-}
-
diff --git a/validation-test/Sema/type_checker_perf/fast/builder_with_nested_closures.swift b/validation-test/Sema/type_checker_perf/fast/builder_with_nested_closures.swift
new file mode 100644
index 0000000000000..e4c1ebb55efd4
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/builder_with_nested_closures.swift
@@ -0,0 +1,71 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=200
+// REQUIRES: tools-release,no_asan
+// REQUIRES: OS=macosx
+
+struct Time {
+  static func +(_: Time, _: Double) -> Time {
+    Time()
+  }
+
+  static func now() -> Time { Time() }
+}
+
+struct Queue {
+  static let current = Queue()
+
+  func after(deadline: Time, execute: () -> Void) {}
+  func after(deadline: Time, execute: (Int) -> Void) {}
+}
+
+func compute(_: () -> Void) {}
+
+protocol P {
+}
+
+@resultBuilder
+struct Builder {
+  static func buildExpression<T: P>(_ v: T) -> T {
+    v
+  }
+
+  static func buildBlock<T: P>(_ v: T) -> T {
+    v
+  }
+
+  static func buildBlokc<T0: P, T1: P>(_ v0: T0, _ v1: T1) -> (T0, T1) {
+    (v0, v1)
+  }
+}
+
+struct MyP: P {
+  func onAction(_: () -> Void) -> some P { self }
+}
+
+class Test {
+  var value = 0.0
+
+  @Builder func test() -> some P {
+    MyP().onAction {
+      Queue.current.after(deadline: .now() + 0.1) {
+        compute {
+          value = 0.3
+          Queue.current.after(deadline: .now() + 0.2) {
+            compute {
+              value = 1.0
+              Queue.current.after(deadline: .now() + 0.2) {
+                compute {
+                  value = 0.3
+                  Queue.current.after(deadline: .now() + 0.2) {
+                    compute {
+                      value = 1.0
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/cgfloat_double_math_mix.swift b/validation-test/Sema/type_checker_perf/fast/cgfloat_double_math_mix.swift
new file mode 100644
index 0000000000000..5a29edf31ea49
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/cgfloat_double_math_mix.swift
@@ -0,0 +1,107 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=200
+// REQUIRES: objc_interop
+
+import Foundation
+
+func f0(_ d: Double, _ f: CGFloat) { _ = { _ = ((((d - 1.0) + (d + 1.0)) / ((1.0 / .pi.squareRoot()) / 1.0)) - ((f - (1.0 * f)) * ((1.0 + 1.0) + (1.0 - d)))) / ((1.0 + .pi) / (1.0 * ((1.0 * .pi.squareRoot()) / (1.0 / f)))) } }
+func f1(_ d: Double, _ f: CGFloat) { _ = { _ = ((f * .pi) * (((f - f) - (1.0 + 1.0)) / f)) / ((.pi.squareRoot() / .pi.squareRoot()) / (((.pi / .pi.squareRoot()) + (1.0 - 1.0)) + d)) } }
+func f2(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 / 1.0) - 1.0) * (((.pi.squareRoot() - .pi.squareRoot()) / 1.0) / (.pi * (1.0 * .pi)))) - ((1.0 + d) + (((1.0 / 1.0) / (1.0 / .pi.squareRoot())) + 1.0)) } }
+func f3(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 - d) / 1.0) * (1.0 + (1.0 / 1.0))) / ((1.0 * (1.0 + f)) + 1.0)) + ((((1.0 / .pi) * (d / .pi.squareRoot())) / (f / (.pi.squareRoot() + 1.0))) + (((d - .pi.squareRoot()) + (d + 1.0)) / (.pi.squareRoot() + (1.0 + .pi.squareRoot())))) } }
+func f4(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 - ((d / f) * 1.0)) - ((1.0 + (d / .pi)) - (1.0 - (1.0 - f)))) * ((((1.0 - f) - (1.0 + .pi)) * ((f * d) - (1.0 / .pi))) + (1.0 * ((.pi.squareRoot() * 1.0) + 1.0))) } }
+func f5(_ d: Double, _ f: CGFloat) { _ = { _ = ((((d * 1.0) * .pi.squareRoot()) + ((.pi.squareRoot() + .pi) / 1.0)) - ((1.0 * (1.0 - 1.0)) / ((f * 1.0) - .pi))) * ((.pi.squareRoot() * 1.0) / (.pi / (.pi - (.pi.squareRoot() + .pi.squareRoot())))) } }
+func f6(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 / ((.pi - 1.0) - (.pi.squareRoot() - 1.0))) - (((.pi + 1.0) + .pi.squareRoot()) * (1.0 + .pi.squareRoot()))) * ((1.0 + .pi.squareRoot()) + (((.pi.squareRoot() - 1.0) + d) + f)) } }
+func f7(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 * 1.0) * (d / f)) - 1.0) - (((.pi.squareRoot() + 1.0) - (.pi.squareRoot() / f)) * (f * (f * .pi)))) - ((((1.0 / 1.0) / (1.0 / 1.0)) / ((1.0 * .pi) * (d * .pi.squareRoot()))) * (.pi + .pi)) } }
+func f8(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 / (1.0 * .pi.squareRoot())) + ((f - 1.0) / .pi)) + ((d - f) + 1.0)) - ((1.0 - ((.pi / 1.0) / .pi.squareRoot())) / (.pi + ((1.0 + f) / (.pi * 1.0)))) } }
+func f9(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 / 1.0) * ((1.0 / 1.0) * (f * 1.0))) / (1.0 / 1.0)) * ((((1.0 - 1.0) + (1.0 - f)) - ((1.0 + .pi) + (f * d))) * (((1.0 + .pi.squareRoot()) / 1.0) / d)) } }
+func f10(_ d: Double, _ f: CGFloat) { _ = { _ = ((((d - .pi.squareRoot()) + (1.0 - d)) + ((d - d) + .pi.squareRoot())) - (((1.0 / .pi) / d) - (1.0 / .pi.squareRoot()))) + ((((1.0 / f) + (d - 1.0)) - (1.0 - 1.0)) / (((d - 1.0) + (.pi.squareRoot() - d)) + ((1.0 + d) / 1.0))) } }
+func f11(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 / .pi.squareRoot()) / (((1.0 * .pi.squareRoot()) / (f * 1.0)) * 1.0)) + ((1.0 / ((1.0 / 1.0) - (d - 1.0))) * (((.pi.squareRoot() * d) + (1.0 * 1.0)) * 1.0)) } }
+func f12(_ d: Double, _ f: CGFloat) { _ = { _ = ((((f - .pi) * .pi) / (1.0 + (1.0 - 1.0))) + ((.pi / (1.0 - 1.0)) + 1.0)) / ((((1.0 / f) / (1.0 / .pi.squareRoot())) - d) * ((d * (1.0 * .pi.squareRoot())) * ((f / .pi.squareRoot()) - (.pi + 1.0)))) } }
+func f13(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi * .pi.squareRoot()) / (1.0 / 1.0)) / ((d + 1.0) - (d - 1.0))) / ((f - f) * ((1.0 - 1.0) + (1.0 / d)))) * (((.pi + (1.0 * f)) * .pi) + ((1.0 - .pi) * d)) } }
+func f14(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 * ((.pi.squareRoot() - 1.0) / (1.0 + .pi))) / ((d / d) / ((1.0 / 1.0) + (.pi / 1.0)))) * ((1.0 * .pi.squareRoot()) + ((1.0 / 1.0) + ((1.0 - 1.0) * 1.0))) } }
+func f15(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 / (d / 1.0)) * .pi) - ((f - (.pi * .pi)) + (1.0 / (d - 1.0)))) + ((((1.0 + 1.0) * (1.0 + 1.0)) + d) + ((1.0 - .pi.squareRoot()) - .pi)) } }
+func f16(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi + .pi.squareRoot()) * (.pi.squareRoot() * 1.0)) + ((.pi.squareRoot() / .pi.squareRoot()) + (1.0 - d))) - (.pi / (1.0 / (1.0 + .pi)))) * (((.pi.squareRoot() / (f / 1.0)) - d) * ((f - (f * f)) - (1.0 * d))) } }
+func f17(_ d: Double, _ f: CGFloat) { _ = { _ = ((((d + .pi) + (1.0 / f)) / (1.0 * (.pi / .pi))) * (f / (.pi + (1.0 - .pi.squareRoot())))) * ((((d + 1.0) * 1.0) - ((.pi / .pi) + (d + .pi))) * (((.pi.squareRoot() + f) - (1.0 - .pi)) / ((f - d) / 1.0))) } }
+func f18(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi + 1.0) + (((f - 1.0) + (d + f)) - ((1.0 * 1.0) + (1.0 / .pi.squareRoot())))) / ((1.0 + ((.pi.squareRoot() * 1.0) + (1.0 - .pi.squareRoot()))) / (f + ((d * f) * (1.0 + 1.0)))) } }
+func f19(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 * (1.0 - .pi.squareRoot())) - ((1.0 * 1.0) / .pi)) - (1.0 + ((.pi.squareRoot() + 1.0) / (d * f)))) + (((1.0 + 1.0) - ((d - .pi.squareRoot()) * (1.0 + 1.0))) - (.pi - (1.0 + (1.0 + 1.0)))) } }
+func f20(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi * (.pi / (1.0 - f))) + (((.pi.squareRoot() + 1.0) + .pi.squareRoot()) - ((.pi + d) - (1.0 + .pi.squareRoot())))) * ((((1.0 + f) / (1.0 * 1.0)) - 1.0) + (d + f)) } }
+func f21(_ d: Double, _ f: CGFloat) { _ = { _ = ((((f - 1.0) + (.pi.squareRoot() * 1.0)) - ((f - 1.0) - (.pi.squareRoot() - 1.0))) + (((1.0 + .pi.squareRoot()) * 1.0) + 1.0)) / ((.pi * 1.0) - (.pi.squareRoot() * ((d + .pi.squareRoot()) / (1.0 * .pi.squareRoot())))) } }
+func f22(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 * .pi.squareRoot()) - .pi.squareRoot()) - ((d + 1.0) * (f - 1.0))) / (f / ((f / 1.0) * d))) - ((d + 1.0) + (1.0 / ((d + f) + (1.0 / .pi)))) } }
+func f23(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 * (f - .pi.squareRoot())) * (1.0 / (.pi / f))) + (((.pi + .pi.squareRoot()) * (f - .pi.squareRoot())) + (d - (1.0 - 1.0)))) + ((.pi / d) - (.pi.squareRoot() - ((1.0 / 1.0) * .pi))) } }
+func f24(_ d: Double, _ f: CGFloat) { _ = { _ = ((((f * 1.0) * (.pi.squareRoot() / d)) - 1.0) - ((1.0 + (d * 1.0)) * 1.0)) - (((.pi / .pi) * 1.0) + (.pi / ((.pi.squareRoot() / 1.0) + (d * 1.0)))) } }
+func f25(_ d: Double, _ f: CGFloat) { _ = { _ = ((((f * f) / (1.0 - d)) + ((.pi.squareRoot() + .pi) * f)) / (1.0 * ((.pi / .pi.squareRoot()) * (f - .pi.squareRoot())))) / ((((1.0 + 1.0) + (f - d)) - .pi.squareRoot()) - ((d / (.pi * .pi)) + ((.pi.squareRoot() / .pi.squareRoot()) - (1.0 * .pi.squareRoot())))) } }
+func f26(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi - 1.0) / (1.0 * .pi.squareRoot())) / ((1.0 - 1.0) * (.pi - .pi))) - (.pi.squareRoot() - (1.0 - (1.0 * d)))) - ((((d + d) / f) + ((.pi.squareRoot() - 1.0) + (1.0 + .pi))) - (.pi.squareRoot() - .pi)) } }
+func f27(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 * .pi) / d) * (.pi.squareRoot() / (.pi.squareRoot() - 1.0))) + (1.0 * ((1.0 + 1.0) + 1.0))) + ((((1.0 / 1.0) - 1.0) - ((1.0 + 1.0) * (.pi.squareRoot() / 1.0))) * (((1.0 - .pi.squareRoot()) + (f * 1.0)) + d)) } }
+func f28(_ d: Double, _ f: CGFloat) { _ = { _ = ((f + .pi) + (((f + d) + (1.0 * .pi.squareRoot())) * 1.0)) - ((((.pi / 1.0) - (1.0 - .pi.squareRoot())) / (1.0 * (.pi.squareRoot() * f))) / (((1.0 * f) / (.pi + .pi.squareRoot())) * (1.0 - (1.0 * 1.0)))) } }
+func f29(_ d: Double, _ f: CGFloat) { _ = { _ = ((((d / .pi) - f) - (1.0 + f)) * (1.0 / d)) * ((((.pi - 1.0) / (1.0 / 1.0)) - d) + (((d * .pi) + 1.0) - d)) } }
+func f30(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 * d) * (f * .pi.squareRoot())) * d) / (((.pi * .pi) - (1.0 / 1.0)) * (1.0 - (d / d)))) / ((((1.0 / .pi) * (1.0 + d)) / ((.pi.squareRoot() + 1.0) / (1.0 + f))) * (((d * .pi) + (.pi * f)) + 1.0)) } }
+func f31(_ d: Double, _ f: CGFloat) { _ = { _ = ((d / .pi.squareRoot()) / ((1.0 / (f + .pi.squareRoot())) * 1.0)) * (((1.0 * (1.0 - .pi.squareRoot())) / ((d / d) + .pi.squareRoot())) / (((1.0 + 1.0) - (1.0 / .pi)) - f)) } }
+func f32(_ d: Double, _ f: CGFloat) { _ = { _ = (((.pi / (f * 1.0)) - ((1.0 - d) / .pi)) * (1.0 * ((.pi - .pi.squareRoot()) - (f * .pi.squareRoot())))) * ((((1.0 - .pi) - (.pi + f)) * ((1.0 - .pi.squareRoot()) / (.pi.squareRoot() / f))) + ((1.0 - (d / 1.0)) - ((1.0 + 1.0) - (f - 1.0)))) } }
+func f33(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 / ((1.0 / f) + (d + d))) + (((1.0 + d) - .pi) * .pi.squareRoot())) - (((.pi / (.pi * f)) + (f + (.pi - d))) + (((.pi * 1.0) + .pi.squareRoot()) + ((f - .pi) / (1.0 * .pi)))) } }
+func f34(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi.squareRoot() + 1.0) / (((1.0 - d) + (.pi.squareRoot() - f)) / d)) + ((f / d) + (((.pi / f) * d) / ((f - d) + (1.0 / .pi.squareRoot())))) } }
+func f35(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 / (1.0 / 1.0)) * ((.pi.squareRoot() / f) / (1.0 * 1.0))) * (.pi.squareRoot() - ((.pi - 1.0) / d))) - ((1.0 - (.pi / 1.0)) - (.pi + (.pi - (.pi * f)))) } }
+func f36(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 / 1.0) - ((1.0 - .pi) * (d / .pi.squareRoot()))) / (((.pi / .pi) * (.pi.squareRoot() * .pi.squareRoot())) - ((f / .pi) * (f * 1.0)))) - ((1.0 + (f / (.pi - f))) / (1.0 * ((.pi.squareRoot() * .pi.squareRoot()) - (1.0 / .pi)))) } }
+func f37(_ d: Double, _ f: CGFloat) { _ = { _ = ((((d + .pi.squareRoot()) / (.pi.squareRoot() - 1.0)) / ((f / 1.0) * (1.0 * 1.0))) - (((1.0 - 1.0) / 1.0) - ((d / .pi.squareRoot()) - 1.0))) - ((1.0 * .pi.squareRoot()) / (.pi.squareRoot() / (.pi - (1.0 / d)))) } }
+func f38(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi.squareRoot() - 1.0) * (1.0 * .pi)) - ((1.0 / f) / (.pi * .pi))) * (((1.0 + 1.0) - .pi.squareRoot()) - (1.0 / (.pi - .pi.squareRoot())))) * (((1.0 + (1.0 - d)) / ((1.0 + 1.0) - (.pi - f))) / (((.pi * .pi) / 1.0) * f)) } }
+func f39(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 * 1.0) * d) + d) - (d / 1.0)) / ((((1.0 * .pi.squareRoot()) * 1.0) * (.pi * 1.0)) / ((.pi - .pi) * 1.0)) } }
+func f40(_ d: Double, _ f: CGFloat) { _ = { _ = ((d - ((f - f) / .pi.squareRoot())) * (((.pi.squareRoot() * 1.0) + 1.0) + (1.0 - (1.0 + 1.0)))) / (((1.0 - (1.0 + .pi.squareRoot())) / 1.0) / (d - .pi.squareRoot())) } }
+func f41(_ d: Double, _ f: CGFloat) { _ = { _ = ((d + ((1.0 - 1.0) + (.pi.squareRoot() / 1.0))) * ((d + (1.0 + d)) * (1.0 - (1.0 + 1.0)))) / ((((f - 1.0) + (.pi.squareRoot() - 1.0)) / ((f / f) - f)) * ((.pi.squareRoot() + (1.0 * f)) * ((1.0 + d) * (1.0 + .pi)))) } }
+func f42(_ d: Double, _ f: CGFloat) { _ = { _ = ((((f * d) / (f - 1.0)) + (1.0 / (.pi + f))) * (((.pi.squareRoot() / f) * 1.0) / ((.pi.squareRoot() / .pi) + (f * 1.0)))) / ((1.0 - ((.pi / 1.0) * (f * 1.0))) - ((1.0 / (f / f)) / (d / (f / 1.0)))) } }
+func f43(_ d: Double, _ f: CGFloat) { _ = { _ = ((d / .pi) * (1.0 * ((f / 1.0) + (f - f)))) - ((f - ((f + 1.0) * (1.0 / d))) / (((1.0 - d) + 1.0) / ((1.0 * .pi.squareRoot()) / 1.0))) } }
+func f44(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi.squareRoot() * 1.0) * (1.0 * .pi.squareRoot())) * ((1.0 - 1.0) / .pi)) - ((.pi.squareRoot() + (d * 1.0)) / ((1.0 - d) - (1.0 * d)))) - ((d + ((.pi - f) / (f - 1.0))) * (((.pi / d) / (d * .pi.squareRoot())) * .pi)) } }
+func f45(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 - 1.0) * d) - (((1.0 * f) * 1.0) * ((1.0 * .pi.squareRoot()) * 1.0))) - ((1.0 + ((1.0 + f) - (.pi.squareRoot() + f))) + (.pi * f)) } }
+func f46(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 + 1.0) * d) * .pi.squareRoot()) / ((d / 1.0) - (1.0 / (.pi - .pi)))) * ((1.0 + .pi.squareRoot()) + (((.pi.squareRoot() + f) / 1.0) - 1.0)) } }
+func f47(_ d: Double, _ f: CGFloat) { _ = { _ = (((f * (1.0 / .pi.squareRoot())) / .pi.squareRoot()) - (((.pi.squareRoot() / .pi.squareRoot()) / (d / 1.0)) + (f - (.pi + d)))) + ((((d + f) - (d / f)) / d) * ((.pi - 1.0) / 1.0)) } }
+func f48(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 * d) / (1.0 + (d / (.pi + .pi)))) - ((((d / .pi) - (.pi - .pi.squareRoot())) / ((1.0 / d) - (f + .pi.squareRoot()))) - ((.pi.squareRoot() / (f + 1.0)) * (.pi * (1.0 / d)))) } }
+func f49(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 - (.pi.squareRoot() + d)) * ((1.0 * f) - (.pi * .pi))) - ((1.0 * (d * 1.0)) + f)) * ((((1.0 - d) + (1.0 - .pi)) * ((1.0 * 1.0) - (.pi.squareRoot() / .pi.squareRoot()))) / (1.0 - 1.0)) } }
+func f50(_ d: Double, _ f: CGFloat) { _ = { _ = ((d * (f + .pi.squareRoot())) - (((d * f) / (.pi + d)) / (.pi.squareRoot() - (.pi / .pi.squareRoot())))) - ((((f + 1.0) + 1.0) * f) * (((1.0 / 1.0) * (.pi / d)) * ((1.0 * f) / (1.0 / d)))) } }
+func f51(_ d: Double, _ f: CGFloat) { _ = { _ = (((.pi.squareRoot() - (1.0 - d)) * (d - d)) / (((.pi * d) / (1.0 + 1.0)) / (.pi - 1.0))) / ((((1.0 - 1.0) / (.pi * f)) + (1.0 * 1.0)) - (((1.0 - 1.0) - d) - ((f / .pi.squareRoot()) / (1.0 + f)))) } }
+func f52(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi - 1.0) / (((f / 1.0) - 1.0) - ((d * .pi) - .pi.squareRoot()))) * ((1.0 + (d + (1.0 + 1.0))) + (((f - .pi) * (.pi / 1.0)) + d)) } }
+func f53(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi * f) - (1.0 - 1.0)) * ((f + 1.0) + 1.0)) * (1.0 / d)) / (((d / (f * 1.0)) + ((1.0 * 1.0) + (d + 1.0))) - (((d * 1.0) - (1.0 - .pi.squareRoot())) / 1.0)) } }
+func f54(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi.squareRoot() + d) / (1.0 + .pi.squareRoot())) * ((.pi.squareRoot() / f) / (1.0 * 1.0))) - (((.pi.squareRoot() * f) - d) / ((1.0 - 1.0) - f))) * ((((.pi - 1.0) / (1.0 + d)) - (d + (1.0 - 1.0))) + (.pi + (1.0 + f))) } }
+func f55(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 + (1.0 + d)) / (f - (1.0 + d))) * (f / (.pi * (1.0 - 1.0)))) / ((((1.0 * .pi) / (d / f)) + ((1.0 / d) / (.pi.squareRoot() * .pi.squareRoot()))) / (1.0 + ((1.0 - 1.0) * (1.0 * 1.0)))) } }
+func f56(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi * d) * (d - f)) - ((.pi.squareRoot() / 1.0) + (.pi - .pi.squareRoot()))) * (((.pi - .pi.squareRoot()) - (1.0 + 1.0)) + f)) * ((1.0 + d) * (f / 1.0)) } }
+func f57(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 + 1.0) - ((1.0 - 1.0) + ((.pi + d) / (1.0 * .pi.squareRoot())))) + ((.pi.squareRoot() / ((.pi.squareRoot() - .pi.squareRoot()) * (.pi * 1.0))) - (1.0 * .pi.squareRoot())) } }
+func f58(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi * 1.0) - 1.0) * d) * (((f - .pi.squareRoot()) - (.pi / f)) / ((d * 1.0) / d))) / ((((1.0 / d) / (1.0 + .pi.squareRoot())) + (1.0 + (1.0 * 1.0))) + (.pi / ((d * f) - (1.0 - 1.0)))) } }
+func f59(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 / .pi.squareRoot()) + (1.0 / 1.0)) + f) / ((d * 1.0) / (1.0 - (.pi.squareRoot() + 1.0)))) / ((((.pi.squareRoot() - d) * (.pi.squareRoot() - .pi.squareRoot())) - ((f / 1.0) - d)) + ((f - (d / .pi)) / (.pi - (1.0 / 1.0)))) } }
+func f60(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 - 1.0) + (f * 1.0)) / (d / (f / 1.0))) - ((1.0 - (1.0 * 1.0)) / ((1.0 / f) + (1.0 + f)))) * ((((.pi.squareRoot() * 1.0) * (d * d)) - (1.0 * (.pi.squareRoot() + f))) + ((1.0 + (.pi.squareRoot() - .pi.squareRoot())) * 1.0)) } }
+func f61(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 + .pi.squareRoot()) * .pi.squareRoot()) + (.pi.squareRoot() + .pi.squareRoot())) * (((1.0 - (f - 1.0)) + d) / (d / d)) } }
+func f62(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 * 1.0) / .pi) / (.pi + 1.0)) + (((f / (1.0 - d)) / ((f / 1.0) + f)) / (d * 1.0)) } }
+func f63(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 + .pi.squareRoot()) * (((f * 1.0) / (d + f)) * ((1.0 + d) - (1.0 * f)))) * ((.pi.squareRoot() * d) * (((1.0 - 1.0) / (d + d)) + (.pi - .pi.squareRoot()))) } }
+func f64(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 + 1.0) + (.pi.squareRoot() * 1.0)) + (.pi.squareRoot() - ((1.0 - 1.0) * 1.0))) + ((((f + f) / (.pi.squareRoot() * 1.0)) - ((1.0 - 1.0) + f)) * (((.pi - d) * .pi) / 1.0)) } }
+func f65(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 / (.pi.squareRoot() - 1.0)) / ((1.0 / 1.0) + d)) - (1.0 + (1.0 - (.pi.squareRoot() / f)))) - ((d + ((.pi.squareRoot() * .pi.squareRoot()) / (.pi.squareRoot() + d))) + (((d * d) * (f - 1.0)) - ((f / 1.0) - (.pi - 1.0)))) } }
+func f66(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 + d) / (1.0 - f)) + (1.0 + 1.0)) - (((d - .pi) - 1.0) * 1.0)) * ((((d - 1.0) + (1.0 + f)) / ((1.0 / d) + (.pi.squareRoot() + d))) * (.pi.squareRoot() - ((f - .pi.squareRoot()) - (.pi.squareRoot() + 1.0)))) } }
+func f67(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 + 1.0) - 1.0) + ((.pi * 1.0) - (.pi + 1.0))) - (((1.0 + .pi.squareRoot()) + (f + .pi)) * (f - f))) + ((((1.0 / 1.0) * d) + .pi.squareRoot()) + ((1.0 / (1.0 / .pi)) - ((1.0 / 1.0) * .pi.squareRoot()))) } }
+func f68(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi / 1.0) + 1.0) - f) / (1.0 / ((1.0 - f) / (1.0 - d)))) + ((.pi.squareRoot() - .pi) - (1.0 / 1.0)) } }
+func f69(_ d: Double, _ f: CGFloat) { _ = { _ = ((((f - f) - (.pi.squareRoot() * .pi)) / (1.0 * (.pi * 1.0))) / (((1.0 / f) / (d * 1.0)) * (.pi + f))) * (((d * (1.0 - 1.0)) - .pi) / (1.0 - 1.0)) } }
+func f70(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi.squareRoot() - d) + (1.0 - ((1.0 / 1.0) / .pi))) * (((.pi + (1.0 - .pi)) + ((1.0 * d) * (d / 1.0))) - (1.0 / ((.pi.squareRoot() / .pi) * f))) } }
+func f71(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi - (.pi + f)) + (.pi / 1.0)) + (((.pi.squareRoot() - (f * 1.0)) / ((1.0 / 1.0) / (1.0 + f))) / (((f + f) * (1.0 - f)) / ((.pi.squareRoot() + f) * (1.0 * d)))) } }
+func f72(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 - .pi) / ((1.0 + 1.0) - (f + 1.0))) - (((.pi * .pi.squareRoot()) / (f + 1.0)) * ((1.0 + 1.0) + f))) + ((((.pi.squareRoot() + f) - (1.0 * .pi)) * ((1.0 / .pi) + (1.0 * d))) / ((.pi - (.pi.squareRoot() + d)) * ((1.0 + 1.0) + (1.0 - d)))) } }
+func f73(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 + d) / (1.0 * d)) - f) - (((1.0 + d) / (1.0 * f)) * ((.pi.squareRoot() / .pi.squareRoot()) + (1.0 * 1.0)))) - ((((d - 1.0) - (1.0 + f)) / ((d * 1.0) / (d + d))) - (((.pi.squareRoot() * 1.0) / (.pi.squareRoot() / 1.0)) / (1.0 + (.pi.squareRoot() - .pi)))) } }
+func f74(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi.squareRoot() / 1.0) / (((.pi.squareRoot() - .pi) + (.pi + 1.0)) - ((1.0 + 1.0) * 1.0))) / ((.pi.squareRoot() / .pi.squareRoot()) / (((1.0 + .pi) - (1.0 / f)) / (1.0 + (.pi.squareRoot() - 1.0)))) } }
+func f75(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi.squareRoot() * 1.0) - 1.0) + f) / (f + 1.0)) - ((((.pi.squareRoot() / .pi) * 1.0) / f) / (f - 1.0)) } }
+func f76(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi.squareRoot() / ((d * .pi) * (f + f))) * (((.pi.squareRoot() * .pi.squareRoot()) / (1.0 + 1.0)) * ((1.0 - d) + (d + .pi.squareRoot())))) - ((((.pi + 1.0) / (1.0 + d)) + ((1.0 + 1.0) * (f - d))) - (f + .pi)) } }
+func f77(_ d: Double, _ f: CGFloat) { _ = { _ = (((.pi - (1.0 / .pi)) * ((.pi.squareRoot() - .pi.squareRoot()) - d)) - (1.0 + ((.pi + d) + 1.0))) + (((d * (.pi - f)) - ((.pi.squareRoot() - 1.0) + (d - .pi))) - (.pi / ((d + 1.0) * (f - f)))) } }
+func f78(_ d: Double, _ f: CGFloat) { _ = { _ = (((.pi / (f / 1.0)) + ((f / f) / .pi.squareRoot())) / (.pi * (.pi.squareRoot() - (.pi.squareRoot() + 1.0)))) + ((((.pi + 1.0) * f) - 1.0) / (((.pi.squareRoot() - .pi) * (.pi.squareRoot() + f)) - f)) } }
+func f79(_ d: Double, _ f: CGFloat) { _ = { _ = ((d / (1.0 - (1.0 - 1.0))) + ((1.0 * 1.0) * ((1.0 / .pi.squareRoot()) * (.pi.squareRoot() * 1.0)))) * ((.pi.squareRoot() / 1.0) / (((1.0 / 1.0) / (1.0 / 1.0)) + ((f - .pi) - d))) } }
+func f80(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 * ((1.0 - 1.0) / 1.0)) + (((f - 1.0) * (.pi.squareRoot() - .pi.squareRoot())) / ((.pi + 1.0) / (1.0 - 1.0)))) - ((((.pi - 1.0) / (1.0 / .pi)) / ((d - 1.0) + (.pi - 1.0))) / (1.0 + (1.0 + (d - 1.0)))) } }
+func f81(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi.squareRoot() * f) / ((1.0 + d) + ((1.0 + 1.0) - (1.0 * .pi.squareRoot())))) / (((.pi / (1.0 * 1.0)) / .pi) - (d * ((.pi / f) / (.pi.squareRoot() / .pi)))) } }
+func f82(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi + .pi.squareRoot()) / (.pi.squareRoot() * .pi)) + ((.pi + 1.0) - .pi)) + (((1.0 / .pi.squareRoot()) + 1.0) / ((.pi + 1.0) + (f + 1.0)))) - ((((f - .pi.squareRoot()) * (1.0 - f)) * ((1.0 + 1.0) / (.pi.squareRoot() - 1.0))) + ((.pi.squareRoot() / .pi) + ((.pi + 1.0) - (1.0 - 1.0)))) } }
+func f83(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 + (d / (f + f))) + (1.0 / f)) - ((((1.0 + .pi) - .pi.squareRoot()) + ((1.0 / .pi) - d)) - (1.0 - (d * (1.0 - d)))) } }
+func f84(_ d: Double, _ f: CGFloat) { _ = { _ = ((d * .pi.squareRoot()) * (((1.0 + 1.0) - 1.0) * .pi)) * ((.pi - f) - ((1.0 - (.pi + 1.0)) * (1.0 - (f / 1.0)))) } }
+func f85(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 - d) / (.pi.squareRoot() + (1.0 - (1.0 - .pi)))) * ((((.pi - 1.0) + d) + f) * ((f * 1.0) - (1.0 - (d / d)))) } }
+func f86(_ d: Double, _ f: CGFloat) { _ = { _ = ((f * (1.0 - 1.0)) / (.pi - d)) / ((((1.0 / .pi) + 1.0) / (f + (.pi.squareRoot() - .pi.squareRoot()))) - (1.0 + ((1.0 / .pi) + (1.0 * .pi)))) } }
+func f87(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 - 1.0) + (1.0 * f)) + (1.0 * (d * .pi.squareRoot()))) - ((1.0 / (.pi.squareRoot() - 1.0)) + (1.0 - (1.0 - .pi)))) - ((.pi.squareRoot() + ((1.0 + 1.0) - (.pi * 1.0))) / (((1.0 * .pi.squareRoot()) * (1.0 + .pi)) * f)) } }
+func f88(_ d: Double, _ f: CGFloat) { _ = { _ = (((d / (f + 1.0)) - ((1.0 - .pi) / (d * d))) - (((d - d) / (1.0 - f)) * ((d + d) + (d + 1.0)))) / ((.pi.squareRoot() + ((1.0 * 1.0) + (.pi.squareRoot() + 1.0))) * (((1.0 + f) - (.pi.squareRoot() / .pi)) + ((1.0 + .pi.squareRoot()) * (d * d)))) } }
+func f89(_ d: Double, _ f: CGFloat) { _ = { _ = ((((1.0 / 1.0) / .pi) * (1.0 * (.pi + .pi))) - ((.pi * .pi) / 1.0)) + (((f - d) - ((1.0 / 1.0) + 1.0)) / ((.pi - 1.0) + 1.0)) } }
+func f90(_ d: Double, _ f: CGFloat) { _ = { _ = ((((.pi + .pi.squareRoot()) * (.pi.squareRoot() + .pi.squareRoot())) * (1.0 / (1.0 / f))) + (((1.0 + d) * (.pi.squareRoot() / f)) - ((d - d) / (f * 1.0)))) - ((((.pi.squareRoot() - 1.0) + (1.0 * f)) + ((1.0 + d) * (.pi.squareRoot() - 1.0))) * ((1.0 / (.pi.squareRoot() - 1.0)) / ((1.0 - .pi.squareRoot()) - (f * 1.0)))) } }
+func f91(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi / ((.pi * 1.0) / (.pi.squareRoot() + 1.0))) * (((.pi + d) / 1.0) - (f - (1.0 / f)))) - ((1.0 / (.pi.squareRoot() - (.pi.squareRoot() * f))) - (1.0 - ((f - 1.0) / (.pi.squareRoot() + 1.0)))) } }
+func f92(_ d: Double, _ f: CGFloat) { _ = { _ = (((.pi - (.pi.squareRoot() + d)) + f) * (f / .pi)) * ((((.pi.squareRoot() / .pi.squareRoot()) / (1.0 + 1.0)) * 1.0) + (((1.0 + 1.0) * 1.0) * ((.pi - f) / .pi.squareRoot()))) } }
+func f93(_ d: Double, _ f: CGFloat) { _ = { _ = ((((d + .pi.squareRoot()) * (d - d)) - (.pi * .pi)) - (f + ((1.0 - d) * (1.0 * .pi.squareRoot())))) - ((d * ((d - d) - (.pi.squareRoot() / 1.0))) - (((.pi.squareRoot() + .pi) * 1.0) + 1.0)) } }
+func f94(_ d: Double, _ f: CGFloat) { _ = { _ = ((1.0 * ((d * 1.0) / .pi.squareRoot())) + (1.0 * ((d / .pi.squareRoot()) + .pi.squareRoot()))) + ((((1.0 - .pi) + 1.0) / 1.0) / (((1.0 - 1.0) * (.pi.squareRoot() - .pi.squareRoot())) / ((1.0 - d) - 1.0))) } }
+func f95(_ d: Double, _ f: CGFloat) { _ = { _ = (((f - (.pi.squareRoot() - 1.0)) * d) / (d + ((1.0 / 1.0) - 1.0))) * ((((.pi.squareRoot() * 1.0) / (1.0 + .pi)) - 1.0) + (d * ((1.0 * 1.0) * .pi.squareRoot()))) } }
+func f96(_ d: Double, _ f: CGFloat) { _ = { _ = ((((f / 1.0) + (d / .pi.squareRoot())) - .pi) * (((1.0 / f) - (1.0 + 1.0)) / 1.0)) * (((.pi / (.pi + .pi.squareRoot())) - ((f * 1.0) - (1.0 + 1.0))) / (((.pi + 1.0) * 1.0) - 1.0)) } }
+func f97(_ d: Double, _ f: CGFloat) { _ = { _ = ((.pi.squareRoot() * ((1.0 - 1.0) - (1.0 / d))) * (((d - .pi.squareRoot()) / (1.0 * .pi)) / .pi)) + (((.pi - 1.0) + 1.0) - (.pi - ((.pi * 1.0) * (1.0 - .pi.squareRoot())))) } }
+func f98(_ d: Double, _ f: CGFloat) { _ = { _ = (((1.0 - 1.0) + ((1.0 + d) + f)) * (((1.0 + f) - (1.0 + .pi.squareRoot())) / ((1.0 - 1.0) * (1.0 + 1.0)))) / ((d * (1.0 + (1.0 / d))) * (((1.0 / .pi) / (.pi * 1.0)) / (d + .pi.squareRoot()))) } }
+func f99(_ d: Double, _ f: CGFloat) { _ = { _ = (((.pi * (f * .pi.squareRoot())) * (d * 1.0)) / (((1.0 * 1.0) / (d + d)) - f)) - ((f + 1.0) * (((.pi.squareRoot() / .pi.squareRoot()) + (f * .pi.squareRoot())) / (1.0 + (1.0 + 1.0)))) } }
+func f100(_ d: Double, _ f: CGFloat) { _ = { _ = (((f * (1.0 - 1.0)) + (d - (1.0 + .pi))) / (((.pi + 1.0) * (1.0 - 1.0)) / .pi.squareRoot())) + ((1.0 * ((1.0 * 1.0) / (d * 1.0))) / (1.0 + ((f * .pi.squareRoot()) * (1.0 + 1.0)))) } }
+
diff --git a/validation-test/Sema/type_checker_perf/fast/cgfloat_with_unary_operators.swift b/validation-test/Sema/type_checker_perf/fast/cgfloat_with_unary_operators.swift
new file mode 100644
index 0000000000000..ebf7490e9cfdf
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/cgfloat_with_unary_operators.swift
@@ -0,0 +1,19 @@
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
+
+// REQUIRES: OS=macosx,no_asan
+// REQUIRES: objc_interop
+
+import Foundation
+import CoreGraphics
+import simd
+
+func test(
+  a: CGFloat,
+  b: CGFloat
+) -> CGFloat {
+  exp(-a * b) *
+  (a * -sin(a * b) * a + ((a * b + a) / b) * cos(a * b) * a) +
+  exp(-a * b) *
+  (-b) *
+  (a * cos(a * b) + ((a * b + a) / b) * sin(a * b))
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/collection_subscript_chains.swift.gyb b/validation-test/Sema/type_checker_perf/fast/collection_subscript_chains.swift.gyb
new file mode 100644
index 0000000000000..b6c74599d5707
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/collection_subscript_chains.swift.gyb
@@ -0,0 +1,13 @@
+// RUN: %scale-test --begin 1 --end 15 --step 1 --select NumLeafScopes %s --expected-exit-code 0
+// REQUIRES: asserts,no_asan
+
+func test(carrierDict: [String : Double]) {
+  var exhaustTemperature: Double
+  exhaustTemperature = (
+    (carrierDict[""] ?? 0.0) +
+%for i in range(N):
+    (carrierDict[""] ?? 0.0) +
+%end
+    (carrierDict[""] ?? 0.0)
+  ) / 4
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/complex_swiftui_padding_conditions.swift b/validation-test/Sema/type_checker_perf/fast/complex_swiftui_padding_conditions.swift
new file mode 100644
index 0000000000000..c9f3af5130530
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/complex_swiftui_padding_conditions.swift
@@ -0,0 +1,17 @@
+// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx10.15 -solver-scope-threshold=5500
+// REQUIRES: OS=macosx
+
+import SwiftUI
+
+func test(a: [(offset: Int, element: Double)],
+          c: Color,
+          x: CGFloat,
+          n: Int
+) -> some View {
+  ForEach(a, id: \.offset) { i, r in
+    RoundedRectangle(cornerRadius: r, style: .continuous)
+      .stroke(c, lineWidth: 1)
+      .padding(.horizontal, x / Double(n) * Double(n - 1 - i) / 2)
+      .padding(.vertical, x / Double(n) * Double(n - 1 - i) / 2)
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/contextual_cgfloat_type_with_operator_chain_arguments.swift b/validation-test/Sema/type_checker_perf/fast/contextual_cgfloat_type_with_operator_chain_arguments.swift
new file mode 100644
index 0000000000000..72fb47673c4ea
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/contextual_cgfloat_type_with_operator_chain_arguments.swift
@@ -0,0 +1,17 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=50
+
+// REQUIRES: OS=macosx,no_asan
+// REQUIRES: objc_interop
+
+import Foundation
+
+struct Size {
+  var width: CGFloat
+  var height: CGFloat
+}
+
+func frame(width: CGFloat?, height: CGFloat?) {}
+
+func test(size: Size?) {
+  frame(width: ((size?.width ?? 0) * 1) + 1.0, height: ((size?.height ?? 0) * 1) + 1.0)
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-46157.swift b/validation-test/Sema/type_checker_perf/fast/issue-46157.swift
new file mode 100644
index 0000000000000..ff96a2e90b318
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-46157.swift
@@ -0,0 +1,7 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=100
+
+// https://github.com/swiftlang/swift/issues/46157
+
+func slow() {
+  let _: (Double) -> Double = { x in x*x*x*x - 3*x*x*x + 2 }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-46253-2.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-46253-2.swift.gyb
new file mode 100644
index 0000000000000..62892e30f6a39
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-46253-2.swift.gyb
@@ -0,0 +1,12 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/46253
+
+func slow() {
+  let d: [Int: (Int) -> Int] = [
+%for i in range(0, N):
+    ${i}: { -$0 },
+%end
+  ]
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-46253.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-46253.swift.gyb
new file mode 100644
index 0000000000000..e250ef84bbb24
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-46253.swift.gyb
@@ -0,0 +1,12 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/46253
+
+func slow() {
+  let d: [Int: (Int) -> Bool] = [
+%for i in range(0, N):
+    ${i}: { $0 == $0 },
+%end
+  ]
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-46420.swift b/validation-test/Sema/type_checker_perf/fast/issue-46420.swift
new file mode 100644
index 0000000000000..754f36ad11512
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-46420.swift
@@ -0,0 +1,10 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=200
+
+// https://github.com/swiftlang/swift/issues/46420
+
+func slow() {
+  let new_M: [Int] = Array<Int>(repeating: 0, count: 200)
+  let _ = (0 ..< 32).map({ (a) -> Int in
+      return new_M[a >> 3] >> ((1 ^ a & 7) * 4) & 15
+  })
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-46680.swift b/validation-test/Sema/type_checker_perf/fast/issue-46680.swift
new file mode 100644
index 0000000000000..de285193de066
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-46680.swift
@@ -0,0 +1,33 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck -solver-scope-threshold=100
+// REQUIRES: objc_interop
+
+// https://github.com/swiftlang/swift/issues/46680
+
+import Foundation
+
+// FIXME: This should be a scale-test but it doesn't allow passing `%clang-importer-sdk`
+
+func slow() {
+  let x = [
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0),
+    NSNumber(value: 0)
+  ]
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-47587.swift b/validation-test/Sema/type_checker_perf/fast/issue-47587.swift
new file mode 100644
index 0000000000000..bd916b18b5d6b
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-47587.swift
@@ -0,0 +1,7 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=100
+
+// https://github.com/swiftlang/swift/issues/47587
+
+func slow() {
+  let _ = ["x"].count > 6 + 1 + 4 + 1 + 40 + 1
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-47685.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-47685.swift.gyb
new file mode 100644
index 0000000000000..dcf66b7567481
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-47685.swift.gyb
@@ -0,0 +1,13 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/47685
+
+func slow() {
+  let a = 0
+
+  let diff = abs(a - a) + abs(a + a)
+%for i in range(0, N):
+             + abs(a - a) + abs(a + a)
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-47896.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-47896.swift.gyb
new file mode 100644
index 0000000000000..1753bbbd6aa9b
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-47896.swift.gyb
@@ -0,0 +1,12 @@
+// RUN: %scale-test --begin 1 --end 6 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/47896
+
+func slow() {
+    let _ = MemoryLayout<OpaquePointer>.size
+%for n in range(0, N):
+           + MemoryLayout<Int32>.size + MemoryLayout<UnsafePointer<UInt8>>.size
+%end
+}
+
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-48155.swift b/validation-test/Sema/type_checker_perf/fast/issue-48155.swift
new file mode 100644
index 0000000000000..89527d093a3e4
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-48155.swift
@@ -0,0 +1,232 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=500
+
+// https://github.com/swiftlang/swift/issues/48155
+
+public struct MatrixNxM<T> {
+    var m: [T]
+    private let xdim : Int
+    private let ydim : Int
+    
+    subscript(i: Int, j: Int) -> T {
+        get {
+            precondition(i*xdim + j < self.m.count, "Index out of matrix bounds \(i) \(j)")
+            
+            return self.m[i*xdim + j]
+        }
+        set {
+            self.m[i*xdim + j] = newValue
+        }
+    }
+    
+    public init(xdim: Int, ydim: Int) {
+        self.xdim = xdim
+        self.ydim = ydim
+        self.m = [Any](repeating: 0.0, count: xdim*ydim) as! [T]
+    }
+}
+
+public struct Matrix4x4 {
+    var m: [Double]
+    
+    subscript(i: Int, j: Int) -> Double {
+        get {
+            precondition(i*4 + j < self.m.count, "Index out of matrix bounds \(i) \(j)")
+            
+            return self.m[i*4 + j]
+        }
+        set {
+            self.m[i*4 + j] = newValue
+        }
+    }
+    
+    public init() {
+        m = [Double](repeating: 0.0, count: 16)
+    }
+    
+    public static func identity() -> Matrix4x4 {
+        var identity = Matrix4x4()
+    
+        identity[0,0] = 1.0;
+        identity[1,1] = 1.0;
+        identity[2,2] = 1.0;
+        identity[3,3] = 1.0;
+    
+        return identity
+    }
+    
+    public func determinant() -> Double {
+        let det = self[0,0] * self[1,1] * self[2,2] * self[3,3] +
+            self[0,0] * self[1,2] * self[2,3] * self[3,1] +
+            self[0,0] * self[1,3] * self[2,1] * self[3,2] +
+            
+            self[0,1] * self[1,0] * self[2,3] * self[3,2] +
+            self[0,1] * self[1,2] * self[2,1] * self[3,3] +
+            self[0,1] * self[1,3] * self[2,2] * self[3,0] +
+            
+            self[0,2] * self[1,0] * self[2,1] * self[3,3] +
+            self[0,2] * self[1,1] * self[2,3] * self[3,0] +
+            self[0,2] * self[1,3] * self[2,0] * self[3,0] +
+            
+            self[0,3] * self[1,0] * self[2,2] * self[3,1] +
+            self[0,3] * self[1,1] * self[2,0] * self[3,2] +
+            self[0,3] * self[1,2] * self[2,1] * self[3,0] -
+            
+            self[0,0] * self[1,1] * self[2,3] * self[3,2] -
+            self[0,0] * self[1,2] * self[2,1] * self[3,3] -
+            self[0,0] * self[1,3] * self[2,2] * self[3,1] -
+            
+            self[0,1] * self[1,0] * self[2,2] * self[3,3] -
+            self[0,1] * self[1,2] * self[2,3] * self[3,0] -
+            self[0,1] * self[1,3] * self[2,0] * self[3,2] -
+            
+            self[0,2] * self[1,0] * self[2,3] * self[3,1] -
+            self[0,2] * self[1,1] * self[2,0] * self[3,3] -
+            self[0,2] * self[1,3] * self[2,1] * self[3,0] -
+            
+            self[0,3] * self[1,0] * self[2,1] * self[3,2] -
+            self[0,3] * self[1,1] * self[2,2] * self[3,0] -
+            self[0,3] * self[1,2] * self[2,0] * self[3,1]
+        
+        return det
+    }
+    
+    public func inverse() -> Matrix4x4 {
+        let det = self.determinant()
+        precondition(det != 0, "Determinant is zero, unable to calculate inverse Matrix")
+        
+        let inv_det = 1.0 / det
+        var inverse = Matrix4x4()
+        
+        inverse[0, 0] = (self[1,1] * self[2,2] * self[3,3] +
+            self[1,2] * self[2,3] * self[3,1] +
+            self[1,3] * self[2,1] * self[3,2] -
+            self[1,1] * self[2,3] * self[3,2] -
+            self[1,2] * self[2,1] * self[3,3] -
+            self[1,3] * self[2,2] * self[3,1]) * inv_det;
+        
+        inverse[0, 1] = (self[0,1] * self[2,3] * self[3,2] +
+            self[0,2] * self[2,1] * self[3,3] +
+            self[1,3] * self[2,2] * self[3,1] -
+            self[0,1] * self[2,2] * self[3,3] -
+            self[0,2] * self[2,3] * self[3,1] -
+            self[0,3] * self[2,1] * self[3,2]) * inv_det;
+        
+        inverse[0, 2] = (self[0,1] * self[1,2] * self[3,3] +
+            self[0,2] * self[1,3] * self[3,1] +
+            self[0,3] * self[1,1] * self[3,2] -
+            self[0,1] * self[1,3] * self[3,2] -
+            self[0,2] * self[1,1] * self[3,3] -
+            self[0,3] * self[1,2] * self[3,1]) * inv_det;
+        
+        inverse[0, 3] = (self[0,1] * self[1,3] * self[2,2] +
+            self[0,2] * self[1,1] * self[2,3] +
+            self[0,3] * self[1,2] * self[2,1] -
+            self[0,1] * self[1,2] * self[2,3] -
+            self[0,2] * self[1,3] * self[2,1] -
+            self[0,3] * self[1,1] * self[2,2]) * inv_det;
+        
+        inverse[1, 0] = (self[1,0] * self[2,3] * self[3,2] +
+            self[1,2] * self[2,0] * self[3,3] +
+            self[1,3] * self[2,2] * self[3,1] -
+            self[1,0] * self[2,2] * self[3,3] -
+            self[1,2] * self[2,3] * self[3,1] -
+            self[1,3] * self[2,0] * self[3,2]) * inv_det;
+        
+        inverse[1, 1] = (self[0,0] * self[2,2] * self[3,3] +
+            self[0,2] * self[2,3] * self[3,1] +
+            self[0,3] * self[2,0] * self[3,2] -
+            self[0,0] * self[2,3] * self[3,2] -
+            self[0,2] * self[2,0] * self[3,3] -
+            self[0,3] * self[2,2] * self[3,0]) * inv_det;
+        
+        
+        inverse[1, 2] = (self[0,0] * self[1,3] * self[3,2] +
+            self[0,2] * self[1,0] * self[3,3] +
+            self[0,3] * self[1,2] * self[3,1] -
+            self[0,0] * self[1,2] * self[3,3] -
+            self[0,2] * self[1,3] * self[3,0] -
+            self[0,3] * self[1,0] * self[3,2]) * inv_det;
+        
+        inverse[1, 3] = (self[0,0] * self[1,2] * self[2,3] +
+            self[0,2] * self[1,3] * self[2,2] +
+            self[0,3] * self[1,0] * self[2,2] -
+            self[0,0] * self[1,3] * self[2,2] -
+            self[0,2] * self[1,0] * self[2,3] -
+            self[0,3] * self[1,2] * self[2,0]) * inv_det;
+        
+        inverse[2, 0] = (self[1,0] * self[2,1] * self[3,3] +
+            self[1,1] * self[2,3] * self[3,1] +
+            self[1,3] * self[2,1] * self[3,2] -
+            self[1,0] * self[2,3] * self[3,1] -
+            self[1,1] * self[2,0] * self[3,3] -
+            self[1,3] * self[2,1] * self[3,0]) * inv_det;
+        
+        inverse[2, 1] = (self[0,0] * self[2,3] * self[3,1] +
+            self[0,1] * self[2,0] * self[3,3] +
+            self[0,3] * self[2,1] * self[3,1] -
+            self[0,0] * self[2,1] * self[3,3] -
+            self[0,1] * self[2,3] * self[3,0] -
+            self[0,3] * self[2,0] * self[3,1]) * inv_det;
+        
+        inverse[2, 2] = (self[0,0] * self[1,1] * self[3,3] +
+            self[0,1] * self[1,3] * self[3,0] +
+            self[0,3] * self[1,0] * self[3,1] -
+            self[0,0] * self[1,3] * self[3,1] -
+            self[0,1] * self[1,0] * self[3,3] -
+            self[0,3] * self[1,1] * self[3,0]) * inv_det;
+        
+        inverse[2, 3] = (self[0,0] * self[1,3] * self[2,1] +
+            self[0,1] * self[1,0] * self[2,3] +
+            self[0,3] * self[1,1] * self[2,0] -
+            self[0,0] * self[1,1] * self[2,3] -
+            self[0,1] * self[1,3] * self[2,0] -
+            self[0,3] * self[1,0] * self[2,1]) * inv_det;
+        
+        inverse[3, 0] = (self[1,0] * self[2,2] * self[3,1] +
+            self[1,1] * self[2,0] * self[3,2] +
+            self[1,2] * self[2,1] * self[3,0] -
+            self[1,0] * self[2,1] * self[3,2] -
+            self[1,1] * self[2,2] * self[3,0] -
+            self[1,2] * self[2,0] * self[3,1]) * inv_det;
+        
+        inverse[3, 1] = (self[0,0] * self[2,1] * self[3,2] +
+            self[0,1] * self[2,2] * self[3,0] +
+            self[0,2] * self[2,0] * self[3,2] -
+            self[0,0] * self[2,2] * self[3,1] -
+            self[0,1] * self[2,0] * self[3,2] -
+            self[0,2] * self[2,1] * self[3,0]) * inv_det;
+        
+        inverse[3, 2] = (self[0,0] * self[1,2] * self[3,1] +
+            self[0,1] * self[1,0] * self[3,2] +
+            self[0,2] * self[1,1] * self[3,0] -
+            self[0,0] * self[1,1] * self[3,2] -
+            self[0,1] * self[1,2] * self[3,0] -
+            self[0,2] * self[1,0] * self[3,1]) * inv_det;
+        
+        inverse[3, 3] = (self[0,0] * self[1,1] * self[2,2] +
+            self[0,1] * self[1,2] * self[2,0] +
+            self[0,2] * self[2,1] * self[2,1] -
+            self[0,0] * self[1,2] * self[2,1] -
+            self[0,1] * self[1,0] * self[2,2] -
+            self[0,2] * self[1,1] * self[2,0]) * inv_det;
+        
+        return inverse
+    }
+}
+
+public func * (a: Matrix4x4, b: Matrix4x4) -> Matrix4x4 {
+    var c = Matrix4x4();
+    
+    for i in 0..<4 {
+        for j in 0..<4 {
+            var ab: Double = 0.0;
+            for k in 0..<4 {
+                ab += a[i,k] * b[k,j];
+            }
+            
+            c[i, j] = ab;
+        }
+    }
+    
+    return c
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-48509.swift b/validation-test/Sema/type_checker_perf/fast/issue-48509.swift
new file mode 100644
index 0000000000000..82b6d40afe3e6
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-48509.swift
@@ -0,0 +1,41 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=100
+
+// https://github.com/swiftlang/swift/issues/48509
+
+struct Calculator {
+
+    let tCrit: Double
+    let predictedValue: ([Double]) -> Double
+}
+
+func slow() {
+  // variable indices
+  let index1 = 0
+  let index2 = 1
+  let index3 = 2
+
+  let _ = Calculator(
+    tCrit: 1.962,
+    predictedValue: { (parameters: [Double]) -> Double in
+        return -603 + 123.31 * parameters[index1] + 9.288 * parameters[index2] + 0.316 * parameters[index3]
+    }
+  )
+
+  let _ = Calculator(
+    tCrit: 1.962,
+    predictedValue: { parameters in
+        -302.908 + 0.162 * parameters[index1] + 3.112 * parameters[index2] + 0.392 * parameters[index3]
+  })
+
+  let _ = Calculator(
+    tCrit: 1.962,
+    predictedValue: { parameters in
+        -992 + 1.312 * parameters[index1] + 1.235 * parameters[index2]
+  })
+
+  let _ = Calculator(
+    tCrit: 1.962,
+    predictedValue: { parameters in
+        -2932.32 + 1.253 * parameters[index1] + 3.212 * parameters[index2]
+  })
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-48588.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-48588.swift.gyb
new file mode 100644
index 0000000000000..0ee58831870a2
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-48588.swift.gyb
@@ -0,0 +1,11 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/48588
+
+func toUInt32(_ a: [UInt8]) -> UInt32 {
+    return (UInt32(a[0]) << 24)
+%for i in range(0, N):
+        + (UInt32(a[1]) << 16)
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-48706.swift b/validation-test/Sema/type_checker_perf/fast/issue-48706.swift
new file mode 100644
index 0000000000000..cd758bf105939
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-48706.swift
@@ -0,0 +1,75 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=100
+
+// https://github.com/swiftlang/swift/issues/48706
+
+struct IssueAssignee {
+    let issueUid: String
+    let assigneeUid: String
+}
+
+struct IssueFollower {
+    let issueUid: String
+    let followerUid: String
+}
+
+struct IssueModel {
+    let uid: String
+    let title: String
+    var assignees: [IssueAssignee] = []
+    var followers: [IssueFollower] = []
+
+    static let joins: [AnyRelationship<IssueModel>] = [
+        OneToMany(\IssueModel.assignees, \IssueAssignee.issueUid, \IssueModel.uid),
+        OneToMany(\IssueModel.followers, \IssueFollower.issueUid, \IssueModel.uid)
+    ]
+}
+
+class AnyRelationship<Base> {
+    func query(withModel model: inout Base) {
+        fatalError("Needs to be overriden!")
+    }
+}
+
+final class OneToMany<One, Many, SharedKey: Equatable>: AnyRelationship<One> {
+    let oneKeyPath: WritableKeyPath<One, [Many]>
+    let manyKeyPath: KeyPath<Many, SharedKey>
+    let joinKeyPath: KeyPath<One, SharedKey>
+
+    init(_ oneKeyPath: WritableKeyPath<One, [Many]>, _ manyKeyPath: KeyPath<Many, SharedKey>, _ joinKeyPath: KeyPath<One, SharedKey>) {
+        self.oneKeyPath = oneKeyPath
+        self.manyKeyPath = manyKeyPath
+        self.joinKeyPath = joinKeyPath
+    }
+
+    override func query(withModel model: inout One) {
+        // Force casts here simulate generic storage that allows us to get values by metatype.
+        // For this playground we only support hardcoded `IssueAssignee` type, but that doesn't change
+        // anything about overall API.
+        if Many.self == IssueAssignee.self {
+            model[keyPath: self.oneKeyPath] = assignees.filter { ($0 as! Many)[keyPath: self.manyKeyPath] == model[keyPath: self.joinKeyPath] } as! [Many]
+        } else if Many.self == IssueFollower.self {
+            model[keyPath: self.oneKeyPath] = followers.filter { ($0 as! Many)[keyPath: self.manyKeyPath] == model[keyPath: self.joinKeyPath] } as! [Many]
+        } else {
+            fatalError()
+        }
+    }
+}
+
+var issue = IssueModel(uid: "1", title: "ABC", assignees: [], followers: [])
+let assignees = [
+    IssueAssignee(issueUid: "1", assigneeUid: "Assigned to Issue 1"),
+    IssueAssignee(issueUid: "2", assigneeUid: "Assigned to Issue 2"),
+    IssueAssignee(issueUid: "1", assigneeUid: "Also assigned to issue 1!!!!")
+]
+
+let followers = [
+    IssueFollower(issueUid: "1", followerUid: "Following Issue 1"),
+    IssueFollower(issueUid: "2", followerUid: "Following Issue 2"),
+    IssueFollower(issueUid: "1", followerUid: "Also following issue 1!!!!")
+]
+
+for join in IssueModel.joins {
+    join.query(withModel: &issue)
+}
+
+print(issue)
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-49635.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-49635.swift.gyb
new file mode 100644
index 0000000000000..0dbf2355cd4f5
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-49635.swift.gyb
@@ -0,0 +1,11 @@
+// RUN: %scale-test --begin 1 --end 8 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/49635
+
+func slow() {
+  (Optional(1) ?? 1) * 1
+%for i in range(0, N):
+  * 1
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-49650.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-49650.swift.gyb
new file mode 100644
index 0000000000000..5de52b6a066f3
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-49650.swift.gyb
@@ -0,0 +1,11 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/49650
+
+func f<T: Numeric>(t: T) -> T{
+  return t * t - t * t
+%for i in range(0, N):
+  + t * t - t * t
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-50046.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-50046.swift.gyb
new file mode 100644
index 0000000000000..7f083db0b6fdb
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-50046.swift.gyb
@@ -0,0 +1,11 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/50046
+
+func slow(x: UInt64) {
+	let _: UInt64 = ((x >> (6 * 1)) & 0xFF) << (8 * 0)
+%for i in range(0, N):
+                  | ((x >> (6 * 3)) & 0xFF) << (8 * 1)
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-51312.swift b/validation-test/Sema/type_checker_perf/fast/issue-51312.swift
new file mode 100644
index 0000000000000..f45396123ef64
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-51312.swift
@@ -0,0 +1,60 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=300
+
+// https://github.com/swiftlang/swift/issues/51312
+
+extension Sequence where Element == Int {
+  var stringValue: String { "" }
+}
+
+func slow() {
+  let _ =
+    (0x0041...0x005A).stringValue + // 'A' to 'Z'
+    (0x0061...0x007A).stringValue + // 'a' to 'z'
+    "_" +
+    "\u{00A8}\u{00AA}\u{00AD}\u{00AF}" +
+    (0x00B2...0x00B5).stringValue +
+    (0x00B7...0x00BA).stringValue +
+    (0x00BC...0x00BE).stringValue +
+    (0x00C0...0x00D6).stringValue +
+    (0x00D8...0x00F6).stringValue +
+    (0x00F8...0x00FF).stringValue +
+    (0x0100...0x02FF).stringValue +
+    (0x0370...0x167F).stringValue +
+    (0x1681...0x180D).stringValue +
+    (0x180F...0x1DBF).stringValue +
+    (0x1E00...0x1FFF).stringValue +
+    (0x200B...0x200D).stringValue +
+    (0x202A...0x202E).stringValue +
+    (0x203F...0x2040).stringValue +
+    "\u{2054}" +
+    (0x2060...0x206F).stringValue +
+    (0x2070...0x20CF).stringValue +
+    (0x2100...0x218F).stringValue +
+    (0x2460...0x24FF).stringValue +
+    (0x2776...0x2793).stringValue +
+    (0x2C00...0x2DFF).stringValue +
+    (0x2E80...0x2FFF).stringValue +
+    (0x3004...0x3007).stringValue +
+    (0x3021...0x302F).stringValue +
+    (0x3031...0x303F).stringValue +
+    (0x3040...0xD7FF).stringValue +
+    (0xF900...0xFD3D).stringValue +
+    (0xFD40...0xFDCF).stringValue +
+    (0xFDF0...0xFE1F).stringValue +
+    (0xFE30...0xFE44).stringValue +
+    (0xFE47...0xFFFD).stringValue +
+    (0x10000...0x1FFFD).stringValue +
+    (0x20000...0x2FFFD).stringValue +
+    (0x30000...0x3FFFD).stringValue +
+    (0x40000...0x4FFFD).stringValue +
+    (0x50000...0x5FFFD).stringValue +
+    (0x60000...0x6FFFD).stringValue +
+    (0x70000...0x7FFFD).stringValue +
+    (0x80000...0x8FFFD).stringValue +
+    (0x90000...0x9FFFD).stringValue +
+    (0xA0000...0xAFFFD).stringValue +
+    (0xB0000...0xBFFFD).stringValue +
+    (0xC0000...0xCFFFD).stringValue +
+    (0xD0000...0xDFFFD).stringValue +
+    (0xE0000...0xEFFFD).stringValue
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-52563.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-52563.swift.gyb
new file mode 100644
index 0000000000000..601f233bc8581
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-52563.swift.gyb
@@ -0,0 +1,15 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/52563
+
+func slow() {
+  let a = 1
+  let b = 1
+  let c = 1
+  let result = [(-b + c) / (2 * a), (-b - c) / (2 * a),
+%for i in range(0, N):
+                (-b + c) / (2 * a), (-b - c) / (2 * a),
+%end
+  ]
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-52629.swift b/validation-test/Sema/type_checker_perf/fast/issue-52629.swift
new file mode 100644
index 0000000000000..b9eb93127981c
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-52629.swift
@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck -verify -solver-scope-threshold=100
+// REQUIRES: objc_interop
+
+// https://github.com/swiftlang/swift/issues/52629
+
+import Foundation
+
+func slow() {
+  let padding: CGFloat = 1
+  let stroke: CGFloat = 15
+  let origin: CGFloat = 2
+  let handleViewHeight: CGFloat = 1
+
+  _ = CGPoint(x: 1, y: (origin + (padding + handleViewHeight/2 + stroke/2))/1.75)
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-53001.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-53001.swift.gyb
new file mode 100644
index 0000000000000..be62cad1f3989
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-53001.swift.gyb
@@ -0,0 +1,14 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/53001
+
+func slow() {
+  let bit: UInt32 = 0
+  let offset: UInt32 = 0
+
+  let result = bit
+%for i in range(0, N):
+             | (bit << offset)
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-53175.swift b/validation-test/Sema/type_checker_perf/fast/issue-53175.swift
new file mode 100644
index 0000000000000..326e02b08506a
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-53175.swift
@@ -0,0 +1,7 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=500
+
+// https://github.com/swiftlang/swift/issues/53175
+
+func slow() {
+  if 0.1 * 5 * 5 * 5 * 5 * 5 * 5 == 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 { }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-54018.swift b/validation-test/Sema/type_checker_perf/fast/issue-54018.swift
new file mode 100644
index 0000000000000..a2bd2eeae544e
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-54018.swift
@@ -0,0 +1,18 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=100
+
+// https://github.com/swiftlang/swift/issues/54018
+
+typealias vec2 = SIMD2<Float>
+struct Quadratic {
+ let p0 : vec2
+ let p1 : vec2
+ let p2 : vec2
+ init(_ p0:vec2, _ p1:vec2, _ p2:vec2) {
+   self.p0 = p0
+   self.p1 = p1
+   self.p2 = p2
+ }
+ func eval(_ t:Float) -> vec2 {
+  return p0 * (1.0 - t) * (1.0 - t) + (p1 * (2.0 * (1.0 - t)) + p2 * t)
+ }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-54143-2.swift b/validation-test/Sema/type_checker_perf/fast/issue-54143-2.swift
new file mode 100644
index 0000000000000..bab7be1f49520
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-54143-2.swift
@@ -0,0 +1,25 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=10
+// REQUIRES: objc_interop
+
+// https://github.com/swiftlang/swift/issues/54143
+
+import Foundation
+
+extension Int {
+
+    public var days: TimeInterval {
+        return TimeInterval(self) * 24.hours
+    }
+
+    public var hours: TimeInterval {
+        return TimeInterval(self) * 60.minutes
+    }
+
+    public var minutes: TimeInterval {
+        return TimeInterval(self) * 60.seconds
+    }
+
+    public var seconds: TimeInterval {
+        return TimeInterval(self)
+    }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-54143-5.swift b/validation-test/Sema/type_checker_perf/fast/issue-54143-5.swift
new file mode 100644
index 0000000000000..99de4bcb8c980
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-54143-5.swift
@@ -0,0 +1,29 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=100
+// REQUIRES: objc_interop
+
+import Foundation
+
+struct UnitRange<Unit> where Unit: Dimension {
+    var range: ClosedRange<Int> {
+        return min...max
+    }
+
+    let min: Int
+    let max: Int
+    let unit: Unit
+
+    func convert(to targetUnit: Unit) -> UnitRange<Unit> {
+        func convertedValue(from value: Int) -> Int {
+            let rounded = Measurement(value: Double(value), unit: unit)
+                .converted(to: targetUnit)
+                .value
+                .rounded()
+            return Int(rounded)
+        }
+        return UnitRange(
+            min: convertedValue(from: min),
+            max: convertedValue(from: max),
+            unit: targetUnit
+        )
+    }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-54466.swift b/validation-test/Sema/type_checker_perf/fast/issue-54466.swift
new file mode 100644
index 0000000000000..19c1e3a4a6b02
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-54466.swift
@@ -0,0 +1,20 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=25000
+// Succeeds in 125ms with 19934 scopes
+
+// https://github.com/swiftlang/swift/issues/54466
+
+func slow() {
+  let items = (1...10).map { _ in
+   (weight: Int.random(in: 1...10), value: Int.random(in: 1...10))
+  }
+  let _ = Dictionary(grouping: items, by: {$0.weight})
+   .mapValues{$0.map{$0.1}}
+   .map{ item in
+   (weight: item.key, value: item.value.filter{
+   $0 >= item.key
+   })
+   }
+   .filter{!$0.value.isEmpty}
+   .sorted{$0.weight < $1.weight}
+   .map{($0.weight, $0.value.sorted{$0 > $1})}
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-54695.swift.gyb b/validation-test/Sema/type_checker_perf/fast/issue-54695.swift.gyb
new file mode 100644
index 0000000000000..890f7e200e5c0
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-54695.swift.gyb
@@ -0,0 +1,11 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/54695
+
+func slow() {
+  var eq3 = 1.0 - 1/3.0
+%for i in range(0, N):
+          + 1/5.0 - 1/7.0
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-54795.swift b/validation-test/Sema/type_checker_perf/fast/issue-54795.swift
new file mode 100644
index 0000000000000..e3ac8bd761e83
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-54795.swift
@@ -0,0 +1,28 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=10000 -target %target-cpu-apple-macosx10.15
+// Succeeds in 60ms with 5572 scopes
+
+// REQUIRES: objc_interop
+// REQUIRES: OS=macosx
+
+// https://github.com/swiftlang/swift/issues/54795
+
+import SwiftUI
+
+struct Breathe: View {
+    static private let colors: [Color] = [Color(#colorLiteral(red: 0.3529411765, green: 0.662745098, blue: 0.6745098039, alpha: 1)), Color(#colorLiteral(red: 0.4078431373, green: 0.7450980392, blue: 0.6549019608, alpha: 1)), Color(#colorLiteral(red: 0.4666666667, green: 0.8196078431, blue: 0.631372549, alpha: 1)), Color(#colorLiteral(red: 0.5179253817, green: 0.8318992257, blue: 0.6992306113, alpha: 1)), Color(#colorLiteral(red: 0.4078431373, green: 0.7333333333, blue: 0.6509803922, alpha: 1)), Color(#colorLiteral(red: 0.3568627451, green: 0.6666666667, blue: 0.6745098039, alpha: 1))]
+
+    @State private var leafSize: CGFloat = 50
+
+    var body: some View {
+        ZStack {
+            ForEach(0..<Self.colors.count, id: \.self) { index in
+                Circle()
+                    .fill(Self.colors[index])
+                    .opacity(0.5)
+                    .offset(x: -self.leafSize / 2)
+                    .rotationEffect(.degrees(Double(index * 360 / Self.colors.count)))
+            }
+        }
+        .frame(width: self.leafSize, height: self.leafSize)
+    }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-56743.swift b/validation-test/Sema/type_checker_perf/fast/issue-56743.swift
new file mode 100644
index 0000000000000..02fd994e8889d
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-56743.swift
@@ -0,0 +1,6 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=100
+// https://github.com/swiftlang/swift/issues/56743
+
+func slow() {
+  _ = Double(1 * 1 + 2 * 0 + -1 * 12) / Double(1 + 2 + 12)
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-57515.swift b/validation-test/Sema/type_checker_perf/fast/issue-57515.swift
new file mode 100644
index 0000000000000..fbef70f16a9dd
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-57515.swift
@@ -0,0 +1,32 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=100
+// REQUIRES: objc_interop
+
+// https://github.com/swiftlang/swift/issues/57515
+
+import Foundation
+
+// not necessary but avoids dependency on existing result builders
+@resultBuilder
+enum Builder<T> {
+    static func buildBlock(_ components: Never...) -> Never {
+        switch components.first! {}
+    }
+}
+
+@Builder<Never> func compute() -> Never {
+// alternatively, if you'd rather avoid the custom builder:
+//@ViewBuilder func compute() -> some View {
+    let width: CGFloat = 100.0
+    let spacePerBox = width + width
+    let _ = floor(spacePerBox + spacePerBox)
+    let _ = width / spacePerBox
+    let _ = width / spacePerBox
+    let _ = width / spacePerBox
+    let _ = width / spacePerBox
+    let _ = width / spacePerBox
+    let _ = width / spacePerBox
+    let _ = width / spacePerBox
+    let _ = width / spacePerBox
+    let _ = width / spacePerBox
+    // each additional one of these lines doubles compile times
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/issue-57821.swift b/validation-test/Sema/type_checker_perf/fast/issue-57821.swift
new file mode 100644
index 0000000000000..76d07154ffa87
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/issue-57821.swift
@@ -0,0 +1,8 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=2000
+// https://github.com/swiftlang/swift/issues/57821
+
+// This could be a bit faster.
+
+func plotSpcPattern(x : Int, y : Int, pattern : Int) -> UInt8 {
+  return UInt8(pattern >> ((~y & 1) * 8 + (~x & 3) * 2) & 3)
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/logical_infix_operator_chains.swift.gyb b/validation-test/Sema/type_checker_perf/fast/logical_infix_operator_chains.swift.gyb
new file mode 100644
index 0000000000000..8f3414e26bf31
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/logical_infix_operator_chains.swift.gyb
@@ -0,0 +1,51 @@
+// RUN: %scale-test --begin 1 --end 20 --step 1 --select NumLeafScopes %s
+// REQUIRES: asserts,no_asan
+
+struct Predicate<T> : Equatable {}
+
+func ||<T>(_: Predicate<T>, _: Predicate<T>) -> Predicate<T> {
+  .init()
+}
+
+func !=<Value, Operand>(_: Operand, _: Operand) -> Predicate<Value> where Operand : Equatable {
+  .init()
+}
+
+func !=<Value, Operand>(_: Operand, _: KeyPath<Value, Operand>) -> Predicate<Value> where Operand : Equatable {
+  .init()
+}
+
+func !=<Value, Operand>(_: KeyPath<Value, Operand>, _: Operand) -> Predicate<Value> where Operand : Equatable {
+  .init()
+}
+
+func !=<Value, Operand>(_: KeyPath<Value, Operand>, _: KeyPath<Value, Operand>) -> Predicate<Value> where Operand : Equatable {
+  .init()
+}
+
+enum Format : UInt, Equatable {
+case simple = 0
+}
+
+struct Parameter {
+  struct Buffers {
+    struct Data {
+      let format: Format
+    }
+
+    let data: Data?
+  }
+
+  var buffers: Buffers
+}
+
+func test(arr: [Parameter]) {
+  for p in arr {
+    if (p.buffers.data != nil && p.buffers.data!.format != .simple) ||
+%for i in range(1, N):
+       (p.buffers.data != nil && p.buffers.data!.format != .simple) ||
+%end
+       (p.buffers.data != nil && p.buffers.data!.format != .simple) {
+    }
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/member_chains_and_operators_with_iou_base_types.swift b/validation-test/Sema/type_checker_perf/fast/member_chains_and_operators_with_iou_base_types.swift
new file mode 100644
index 0000000000000..d00b81af40f38
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/member_chains_and_operators_with_iou_base_types.swift
@@ -0,0 +1,35 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck -solver-expression-time-threshold=1
+
+// REQUIRES: OS=macosx,no_asan
+// REQUIRES: objc_interop
+
+import Foundation
+
+struct CGRect {
+  var x: CGFloat
+
+  init(x: CGFloat, y: CGFloat, width: CGFloat, height: CGFloat) { }
+  init(x: Double, y: Double, width: Double, height: Double) { }
+}
+
+protocol View {}
+
+extension Optional: View where Wrapped: View {}
+
+extension View {
+  func frame() -> some View { self }
+  func frame(x: Int, y: Int, w: Int, z: Int) -> some View { self }
+  func frame(y: Bool) -> some View { self }
+}
+
+struct NSView {
+  var frame: CGRect
+}
+
+func test(margin: CGFloat, view: NSView!) -> CGRect {
+  // `view` is first attempted as `NSView?` and only if that fails is force unwrapped
+  return CGRect(x: view.frame.x + margin,
+                y: view.frame.x + margin,
+                width: view.frame.x - view.frame.x - view.frame.x - (margin * 2),
+                height: margin)
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/nil_coalescing.swift.gyb b/validation-test/Sema/type_checker_perf/fast/nil_coalescing.swift.gyb
new file mode 100644
index 0000000000000..af8639d9bc159
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/nil_coalescing.swift.gyb
@@ -0,0 +1,9 @@
+// RUN: %scale-test --begin 1 --end 10 --step 1 --select NumLeafScopes %s
+// REQUIRES: asserts,no_asan
+
+func t(_ x: Int?) -> Int {
+  return (x ?? 0)
+%for i in range(1, N):
+         + (x ?? 0)
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/nil_coalescing_dictionary_values.swift.gyb b/validation-test/Sema/type_checker_perf/fast/nil_coalescing_dictionary_values.swift.gyb
new file mode 100644
index 0000000000000..125e6b4218266
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/nil_coalescing_dictionary_values.swift.gyb
@@ -0,0 +1,10 @@
+// RUN: %scale-test --begin 1 --end 10 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+let x: Int?
+
+let _ = [
+%for i in range(0, N):
+  "${i}" : x ?? 0,
+%end
+]
diff --git a/validation-test/Sema/type_checker_perf/fast/operator_chain_with_closures.swift.gyb b/validation-test/Sema/type_checker_perf/fast/operator_chain_with_closures.swift.gyb
new file mode 100644
index 0000000000000..2703b185b23f1
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/operator_chain_with_closures.swift.gyb
@@ -0,0 +1,15 @@
+// RUN: %scale-test --begin 1 --end 10 --step 1 --select NumLeafScopes %s
+// REQUIRES: asserts,no_asan
+
+struct Test {
+    var values: [Int]
+}
+
+func test(t: [Test]) {
+  let _ = 0
+    + 1
+%for i in range(1, N):
+    + 1
+%end
+    + t.map(\.values.count).reduce(0, +)
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/operator_chain_with_hetergeneous_arguments.swift b/validation-test/Sema/type_checker_perf/fast/operator_chain_with_hetergeneous_arguments.swift
similarity index 90%
rename from validation-test/Sema/type_checker_perf/slow/operator_chain_with_hetergeneous_arguments.swift
rename to validation-test/Sema/type_checker_perf/fast/operator_chain_with_hetergeneous_arguments.swift
index 5d6c8c4440ece..787509fb565b2 100644
--- a/validation-test/Sema/type_checker_perf/slow/operator_chain_with_hetergeneous_arguments.swift
+++ b/validation-test/Sema/type_checker_perf/fast/operator_chain_with_hetergeneous_arguments.swift
@@ -5,5 +5,4 @@
 func test(bytes: Int, length: UInt32) {
   // left-hand side of `>=` is `Int` and right-hand side is a chain of `UInt32` inferred from `length`
   _ = bytes >= 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + length
-  // expected-error@-1 {{reasonable time}}
 }
diff --git a/validation-test/Sema/type_checker_perf/fast/operator_chains_separated_by_ternary.swift.gyb b/validation-test/Sema/type_checker_perf/fast/operator_chains_separated_by_ternary.swift.gyb
new file mode 100644
index 0000000000000..9e3a298c66295
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/operator_chains_separated_by_ternary.swift.gyb
@@ -0,0 +1,18 @@
+// RUN: %scale-test --begin 1 --end 12 --step 1 --select NumLeafScopes %s
+// REQUIRES: asserts,no_asan
+
+func compute(_: UInt32) {
+}
+
+func test(cond: Bool) {
+    compute(cond
+       ? 1
+%for i in range(1, N):
+         + 1
+%end
+       : 1
+%for i in range(1, N):
+         * 1
+%end
+    )
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/operators_inside_closure.swift b/validation-test/Sema/type_checker_perf/fast/operators_inside_closure.swift
new file mode 100644
index 0000000000000..49d44feb86b28
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/operators_inside_closure.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-frontend -typecheck %s -solver-scope-threshold=10000
+// REQUIRES: tools-release,no_asan
+
+// Selecting operators from the closure before arguments to `zip` makes this "too complex"
+func compute(_ ids: [UInt64]) {
+  let _ = zip(ids[ids.indices.dropLast()], ids[ids.indices.dropFirst()]).map { pair in
+    ((pair.0 % 2 == 0) && (pair.1 % 2 == 1)) ? UInt64(pair.1 - pair.0) : 42
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/property_vs_unapplied_func.swift b/validation-test/Sema/type_checker_perf/fast/property_vs_unapplied_func.swift
index 9cd53902f42ad..0f44ea3c31032 100644
--- a/validation-test/Sema/type_checker_perf/fast/property_vs_unapplied_func.swift
+++ b/validation-test/Sema/type_checker_perf/fast/property_vs_unapplied_func.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1 -solver-disable-shrink
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
 // REQUIRES: tools-release,no_asan
 
 struct Date {
diff --git a/validation-test/Sema/type_checker_perf/fast/rdar133340307.swift b/validation-test/Sema/type_checker_perf/fast/rdar133340307.swift
new file mode 100644
index 0000000000000..9740b4d15f06c
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/rdar133340307.swift
@@ -0,0 +1,134 @@
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
+// REQUIRES: tools-release,no_asan
+
+public protocol Applicative {}
+
+public struct Kind<X, Y> {}
+
+public extension Applicative {
+    static func product<A1,B> (_ fa:Kind<Self,A1>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,B> (_ fa:Kind<Self,(A1,A2)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,B> (_ fa:Kind<Self,(A1,A2,A3)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,B> (_ fa:Kind<Self,(A1,A2,A3,A4)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29,B)> {
+        fatalError()
+    }
+
+    static func product<A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29,A30,B> (_ fa:Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29,A30)>, _ fb:Kind<Self,B>) -> Kind<Self,(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29,A30,B)> {
+        fatalError()
+    }
+}
+
+public extension Applicative {
+    static func zip<A0,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29> (_ fa0:Kind<Self,A0>, _ fa1:Kind<Self,A1>, _ fa2:Kind<Self,A2>, _ fa3:Kind<Self,A3>, _ fa4:Kind<Self,A4>, _ fa5:Kind<Self,A5>, _ fa6:Kind<Self,A6>, _ fa7:Kind<Self,A7>, _ fa8:Kind<Self,A8>, _ fa9:Kind<Self,A9>, _ fa10:Kind<Self,A10>, _ fa11:Kind<Self,A11>, _ fa12:Kind<Self,A12>, _ fa13:Kind<Self,A13>, _ fa14:Kind<Self,A14>, _ fa15:Kind<Self,A15>, _ fa16:Kind<Self,A16>, _ fa17:Kind<Self,A17>, _ fa18:Kind<Self,A18>, _ fa19:Kind<Self,A19>, _ fa20:Kind<Self,A20>, _ fa21:Kind<Self,A21>, _ fa22:Kind<Self,A22>, _ fa23:Kind<Self,A23>, _ fa24:Kind<Self,A24>, _ fa25:Kind<Self,A25>, _ fa26:Kind<Self,A26>, _ fa27:Kind<Self,A27>, _ fa28:Kind<Self,A28>, _ fa29:Kind<Self,A29>) -> Kind<Self,(A0,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29)> {
+        product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(product(fa0, fa1), fa2), fa3), fa4), fa5), fa6), fa7), fa8), fa9), fa10), fa11), fa12), fa13), fa14), fa15), fa16), fa17), fa18), fa19), fa20), fa21), fa22), fa23), fa24), fa25), fa26), fa27), fa28), fa29) // Ok
+    }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/rdar144100160.swift b/validation-test/Sema/type_checker_perf/fast/rdar144100160.swift
new file mode 100644
index 0000000000000..7e80fd5c3d6c8
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/rdar144100160.swift
@@ -0,0 +1,12 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=100
+// REQUIRES: asserts,no_asan
+
+typealias TimeInterval = Double
+
+struct Date {
+  func addingTimeInterval(_: TimeInterval) -> Date { Date() }
+}
+
+func test(date: Date) {
+  _ = date.addingTimeInterval(TimeInterval(60 * 60 * 24 * 6 + 12 * 60 + 12 + 1))
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/rdar22770433.swift b/validation-test/Sema/type_checker_perf/fast/rdar22770433.swift
new file mode 100644
index 0000000000000..0c51c9346d7ac
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/rdar22770433.swift
@@ -0,0 +1,8 @@
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
+// REQUIRES: tools-release,no_asan
+
+func test(n: Int) -> Int {
+  return n == 0 ? 0 : (0..<n).reduce(0) {
+    ($0 > 0 && $1 % 2 == 0) ? ((($0 + $1) - ($0 + $1)) / ($1 - $0)) + (($0 + $1) / ($1 - $0)) : $0
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/rdar31742586.swift b/validation-test/Sema/type_checker_perf/fast/rdar31742586.swift
new file mode 100644
index 0000000000000..83a3aa1ffa110
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/rdar31742586.swift
@@ -0,0 +1,6 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=1000
+// REQUIRES: tools-release,no_asan
+
+func rdar31742586() -> Double {
+  return -(1 + 2) + -(3 + 4) + 5 - (-(1 + 2) + -(3 + 4) + 5)
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/rdar35213699.swift b/validation-test/Sema/type_checker_perf/fast/rdar35213699.swift
new file mode 100644
index 0000000000000..b5a73088942bb
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/rdar35213699.swift
@@ -0,0 +1,7 @@
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
+// REQUIRES: tools-release,no_asan
+
+func test() {
+  let _: UInt = 1 * 2 + 3 * 4 + 5 * 6 + 7 * 8 + 9 * 10 + 11 * 12 + 13 * 14
+}
+
diff --git a/validation-test/Sema/type_checker_perf/slow/rdar46713933_literal_arg.swift b/validation-test/Sema/type_checker_perf/fast/rdar46713933_literal_arg.swift
similarity index 85%
rename from validation-test/Sema/type_checker_perf/slow/rdar46713933_literal_arg.swift
rename to validation-test/Sema/type_checker_perf/fast/rdar46713933_literal_arg.swift
index a0628335b9c36..5256a92a787c7 100644
--- a/validation-test/Sema/type_checker_perf/slow/rdar46713933_literal_arg.swift
+++ b/validation-test/Sema/type_checker_perf/fast/rdar46713933_literal_arg.swift
@@ -8,5 +8,4 @@ func wrap<T: ExpressibleByStringLiteral>(_ key: String, _ value: T) -> T { retur
 
 func wrapped() -> Int {
   return wrap("1", 1) + wrap("1", 1) + wrap("1", 1) + wrap("1", 1) + wrap("1", 1) + wrap("1", 1)
-  // expected-error@-1 {{the compiler is unable to type-check this expression in reasonable time}}
 }
diff --git a/validation-test/Sema/type_checker_perf/fast/rdar47492691.swift b/validation-test/Sema/type_checker_perf/fast/rdar47492691.swift
index 47fcdcb0771af..7a25cca734f79 100644
--- a/validation-test/Sema/type_checker_perf/fast/rdar47492691.swift
+++ b/validation-test/Sema/type_checker_perf/fast/rdar47492691.swift
@@ -7,3 +7,7 @@ import simd
 func test(foo: CGFloat, bar: CGFloat) {
   _ = CGRect(x: 0.0 + 1.0, y: 0.0 + foo, width: 3.0 - 1 - 1 - 1.0, height: bar)
 }
+
+func test_with_generic_func_and_literals(bounds: CGRect) {
+  _ = CGRect(x: 0, y: 0, width: 1, height: bounds.height - 2 + bounds.height / 2 + max(bounds.height / 2, bounds.height / 2))
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/rdar91310777.swift b/validation-test/Sema/type_checker_perf/fast/rdar91310777.swift
new file mode 100644
index 0000000000000..18450b15fe401
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/rdar91310777.swift
@@ -0,0 +1,15 @@
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
+// REQUIRES: tools-release,no_asan
+
+func compute(_ cont: () -> Void) {}
+
+func test() {
+  compute {
+    let x = 42
+    compute {
+      print(x)
+      let v: UInt64 = UInt64((24 / UInt32(1)) + UInt32(0) - UInt32(0) - 24 / 42 - 42)
+      print(v)
+    }
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/should_skip_bitwise_2.swift b/validation-test/Sema/type_checker_perf/fast/should_skip_bitwise_2.swift
index fdcfab315d3ad..d7d37c8b65b93 100644
--- a/validation-test/Sema/type_checker_perf/fast/should_skip_bitwise_2.swift
+++ b/validation-test/Sema/type_checker_perf/fast/should_skip_bitwise_2.swift
@@ -1,3 +1,3 @@
-// RUN: %target-swift-frontend -typecheck %s -solver-scope-threshold=2000
+// RUN: %target-swift-frontend -typecheck %s -solver-scope-threshold=4000
 
 func f896() { let _ = ((0 >> ((0 >> 0) + ((0 / 0) & 0))) >> (0 << ((0 << 0) >> (0 << (0 << 0))))) }
diff --git a/validation-test/Sema/type_checker_perf/fast/simd_scalar_multiple.swift.gyb b/validation-test/Sema/type_checker_perf/fast/simd_scalar_multiple.swift.gyb
new file mode 100644
index 0000000000000..92dc4a083aa5f
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/simd_scalar_multiple.swift.gyb
@@ -0,0 +1,14 @@
+// RUN: %scale-test --begin 1 --end 5 --step 1 --select NumLeafScopes %s
+
+// REQUIRES: asserts,no_asan
+
+// Flaky is some configurations including simulators
+// REQUIRES: OS=macosx
+// REQUIRES: CPU=arm64 || CPU=arm64e
+
+func f(c: Float, a: SIMD2<Float>) -> SIMD2<Float> {
+  return (c * a)
+%for i in range(1, N):
+         + (c * a)
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/fast/string_interpolations.swift.gyb b/validation-test/Sema/type_checker_perf/fast/string_interpolations.swift.gyb
new file mode 100644
index 0000000000000..fd54e39b609c7
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/string_interpolations.swift.gyb
@@ -0,0 +1,26 @@
+// RUN: %scale-test --begin 1 --end 10 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts,no_asan
+
+struct MyString {
+}
+
+extension MyString: ExpressibleByStringLiteral {
+  init(stringLiteral value: String) {}
+}
+
+func +(_: MyString, _: MyString) -> MyString {}
+
+func test(_: @autoclosure () -> String) {}
+func test(_: () -> String) {}
+func test(_: Character) {}
+
+func test(names: [String]) {
+  var resultString = ""
+  for name in names {
+    test("\(name)"
+%for i in range(0, N):
+      + "\(name)"
+%end
+      + "\(name)")
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/swift_package_index_1.swift b/validation-test/Sema/type_checker_perf/fast/swift_package_index_1.swift
similarity index 77%
rename from validation-test/Sema/type_checker_perf/slow/swift_package_index_1.swift
rename to validation-test/Sema/type_checker_perf/fast/swift_package_index_1.swift
index 934a80472f9c9..edcc58b5c71eb 100644
--- a/validation-test/Sema/type_checker_perf/slow/swift_package_index_1.swift
+++ b/validation-test/Sema/type_checker_perf/fast/swift_package_index_1.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-scope-threshold=1000
+// RUN: %target-swift-frontend -typecheck %s -solver-scope-threshold=700
 // REQUIRES: tools-release,no_asan
 
 public class Cookie {
@@ -13,7 +13,7 @@ public class Cookie {
     private let fixedByteSize: Int32 = 56
 
     var totalByteCount: Int32 {
-        return fixedByteSize + // expected-error {{the compiler is unable to type-check this expression in reasonable time}}
+        return fixedByteSize +
                (port != nil ? 2 : 0) +
                Int32(comment?.utf8.count ?? 0) +
                Int32(commentURL?.utf8.count ?? 0) +
diff --git a/validation-test/Sema/type_checker_perf/slow/swift_package_index_4.swift b/validation-test/Sema/type_checker_perf/fast/swift_package_index_4.swift
similarity index 94%
rename from validation-test/Sema/type_checker_perf/slow/swift_package_index_4.swift
rename to validation-test/Sema/type_checker_perf/fast/swift_package_index_4.swift
index 8b05bedbea950..eaff8718abba3 100644
--- a/validation-test/Sema/type_checker_perf/slow/swift_package_index_4.swift
+++ b/validation-test/Sema/type_checker_perf/fast/swift_package_index_4.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-scope-threshold=60000
+// RUN: %target-swift-frontend -typecheck %s -solver-scope-threshold=60000
 // REQUIRES: tools-release,no_asan
 
 protocol ArgumentProtocol {}
@@ -47,7 +47,7 @@ struct Options {
 
   static func evaluate(_ mode: CommandMode) -> Result<Options, ConcreteError> {
     let defaultBuildDirectory = ""
-    return create // expected-error {{the compiler is unable to type-check this expression in reasonable time}}
+    return create
       <*> mode <| Option(key: "", defaultValue: nil, usage: "")
       <*> mode <| Option(key: "", defaultValue: nil, usage: "")
       <*> mode <| Option(key: "", defaultValue: FileManager.default.currentDirectoryPath, usage: "")
diff --git a/validation-test/Sema/type_checker_perf/fast/swift_package_index_5.swift b/validation-test/Sema/type_checker_perf/fast/swift_package_index_5.swift
new file mode 100644
index 0000000000000..3f8bf5f2021c7
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/fast/swift_package_index_5.swift
@@ -0,0 +1,13 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=1000 -swift-version 5
+// REQUIRES: tools-release,no_asan
+
+func g<T>(_: T) throws {
+    let _: T? =
+        (try? f() as? T) ??
+        (try? f() as? T) ??
+        (try? f() as? T) ??
+        (try? f() as? T) ??
+        (try? f() as? T)
+}
+
+func f() throws -> Int { return 0 }
diff --git a/validation-test/Sema/type_checker_perf/slow/array_count_property_vs_method.swift b/validation-test/Sema/type_checker_perf/slow/array_count_property_vs_method.swift
new file mode 100644
index 0000000000000..abcd1cfc545ce
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/array_count_property_vs_method.swift
@@ -0,0 +1,11 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=5000
+// REQUIRES: tools-release,no_asan
+// REQUIRES: OS=macosx
+
+// FIXME: Array literals are considered "speculative" bindings at the moment but they cannot actually
+// assume different types unlike integer and floating-pointer literals.
+func f(n: Int, a: [Int]) {
+  // expected-error@+1 {{the compiler is unable to type-check this expression in reasonable time}}
+  let _ = [(0 ..< n + a.count).map { Int8($0) }] +
+          [(0 ..< n + a.count).map { Int8($0) }.reversed()] // Ok
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/borderline_flat_map_operator_mix.swift b/validation-test/Sema/type_checker_perf/slow/borderline_flat_map_operator_mix.swift
new file mode 100644
index 0000000000000..b88a73d90121f
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/borderline_flat_map_operator_mix.swift
@@ -0,0 +1,24 @@
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
+
+// REQUIRES: no_asan
+
+struct S {
+    var t: Double
+
+    init(_ t: Double) {
+       self.t = t
+    }
+}
+
+// Note: One possible approach to this issue would be to determine when the array literal inside of the inner closure
+// doesn't have any other possible bindings but Array and attempt it at that point. That would fail overload of flatMap
+// that returns an optional value.
+func f(x: Array<S>, y: Range<Int>) -> [S] {
+    return x.flatMap { z in // expected-error {{the compiler is unable to type-check this expression in reasonable time}}
+        return ((y.lowerBound / 1)...(y.upperBound + 1) / 1).flatMap { w in
+            return [S(1 * Double(w) + 1.0 + z.t),
+                    S(1 * Double(w) + 1.0 - z.t)]
+        }
+    }
+}
+
diff --git a/validation-test/Sema/type_checker_perf/slow/collections_chained_with_plus.swift.gyb b/validation-test/Sema/type_checker_perf/slow/collections_chained_with_plus.swift.gyb
new file mode 100644
index 0000000000000..82e558a5a73fb
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/collections_chained_with_plus.swift.gyb
@@ -0,0 +1,18 @@
+// RUN: %scale-test --invert-result --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+struct Value: RandomAccessCollection, RangeReplaceableCollection {
+  let startIndex = 0
+  let endIndex = 0
+
+  subscript(_: Int) -> Int { 0 }
+
+  func replaceSubrange<C: Collection>(_: Range<Int>, with: C) {}
+}
+
+func f(v: Value) {
+  let _ = v
+%for i in range(0, N):
+	  + v
+%end
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-43274.swift b/validation-test/Sema/type_checker_perf/slow/issue-43274.swift
new file mode 100644
index 0000000000000..34c7faf59c4ca
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-43274.swift
@@ -0,0 +1,1728 @@
+// RUN: %target-typecheck-verify-swift -solver-disable-splitter
+
+// FIXME: This uses too much memory with the splitter.
+
+// https://github.com/swiftlang/swift/issues/43274
+
+public enum Symbol: String {
+   case ThisKeyword = "this"
+   case NewKeyword = "new"
+   case SubtractionOperator = "-"
+   case MultiplicationOperator = "*"
+   case Period = "."
+   case DivisionOperator = "/"
+   case ModulusOperator = "%"
+   case AdditionOperator = "+"
+   case GreaterThanOperator = ">"
+   case LessThanOperator = "<"
+   case GreaterThanEqualOperator = ">="
+   case LessThanEqualsOperator = "<="
+   case InstanceofKeyword = "instanceof"
+   case EqualsEqualsOperator = "=="
+   case NotEqualOperator = "!="
+   case AndOperator = "&&"
+   case OrOperator = "||"
+   case EqualsOperator = "="
+   case BitwiseOrOperator = "|"
+   case BitwiseAndOperator = "&"
+   case ComplementOperator = "!"
+   case BOF = "BOF"
+   case EOF = "EOF"
+   case Identifier = "id"
+   case IntegerLiteral = "integerliteral"
+   case BooleanLiteral = "booleanliteral"
+   case CharacterLiteral = "characterliteral"
+   case StringLiteral = "stringliteral"
+   case NullLiteral = "nullliteral"
+   case ByteKeyword = "byte"
+   case ShortKeyword = "short"
+   case IntKeyword = "int"
+   case CharKeyword = "char"
+   case BooleanKeyword = "boolean"
+   case Semicolon = ";"
+   case Comma = ","
+   case LeftBrace = "{"
+   case RightBrace = "}"
+   case LeftBracket = "["
+   case RightBracket = "]"
+   case LeftParenthesis = "("
+   case RightParenthesis = ")"
+   case ReturnKeyword = "return"
+   case ForKeyword = "for"
+   case IfKeyword = "if"
+   case ElseKeyword = "else"
+   case WhileKeyword = "while"
+   case ClassKeyword = "class"
+   case NativeKeyword = "native"
+   case StaticKeyword = "static"
+   case AbstractKeyword = "abstract"
+   case ProtectedKeyword = "protected"
+   case PackageKeyword = "package"
+   case PublicKeyword = "public"
+   case ImportKeyword = "import"
+   case VoidKeyword = "void"
+   case ImplementsKeyword = "implements"
+   case ExtendsKeyword = "extends"
+   case InterfaceKeyword = "interface"
+   case FinalKeyword = "final"
+
+   /* TODO: non-terminals */
+
+   public var isTerminal: Bool {
+      switch self {
+      case .ThisKeyword,
+           .NewKeyword,
+           .SubtractionOperator,
+           .MultiplicationOperator,
+           .Period,
+           .DivisionOperator,
+           .ModulusOperator,
+           .AdditionOperator,
+           .GreaterThanOperator,
+           .LessThanOperator,
+           .GreaterThanEqualOperator,
+           .LessThanEqualsOperator,
+           .InstanceofKeyword,
+           .EqualsEqualsOperator,
+           .NotEqualOperator,
+           .AndOperator,
+           .OrOperator,
+           .EqualsOperator,
+           .BitwiseOrOperator,
+           .BitwiseAndOperator,
+           .ComplementOperator,
+           .BOF,
+           .EOF,
+           .Identifier,
+           .IntegerLiteral,
+           .BooleanLiteral,
+           .CharacterLiteral,
+           .StringLiteral,
+           .NullLiteral,
+           .ByteKeyword,
+           .ShortKeyword,
+           .IntKeyword,
+           .CharKeyword,
+           .BooleanKeyword,
+           .Semicolon,
+           .Comma,
+           .LeftBrace,
+           .RightBrace,
+           .LeftBracket,
+           .RightBracket,
+           .LeftParenthesis,
+           .RightParenthesis,
+           .ReturnKeyword,
+           .ForKeyword,
+           .IfKeyword,
+           .ElseKeyword,
+           .WhileKeyword,
+           .ClassKeyword,
+           .NativeKeyword,
+           .StaticKeyword,
+           .AbstractKeyword,
+           .ProtectedKeyword,
+           .PackageKeyword,
+           .PublicKeyword,
+           .ImportKeyword,
+           .VoidKeyword,
+           .ImplementsKeyword,
+           .ExtendsKeyword,
+           .InterfaceKeyword,
+           .FinalKeyword:
+         return true
+      }
+   }
+
+   public var isNonTerminal: Bool {
+      return !isTerminal
+   }
+}
+struct ParseTable {
+   struct ProductionRule {
+      let lhs: Symbol
+      let rhs: [Symbol]
+   }
+
+   struct State {
+      let lookaheadToProductionRuleMap: [Symbol: ProductionRule]
+      let lookaheadToNextStateMap: [Symbol: Int]
+   }
+
+   let states: [State]
+   let startState: State
+
+   init(states: [State], startStateIndex: Int) {
+      precondition(!states.isEmpty)
+
+      self.states = states
+      self.startState = states[startStateIndex]
+   }
+
+   func productionRuleForCurrentState(state: State, lookahead: Symbol) -> ProductionRule? {
+      return state.lookaheadToProductionRuleMap[lookahead]
+   }
+
+   func nextStateForCurrentState(state: State, lookahead: Symbol) -> State? {
+      guard let nextStateIndex = state.lookaheadToNextStateMap[lookahead] else {
+         return nil
+      }
+
+      return states[nextStateIndex]
+   }
+}
+struct Joos1W {
+   static func f() {
+      var _ = [
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "BOF")!: 196
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "native")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "void")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "abstract")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "public")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "interface")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "final")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "static")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "class")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "protected")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "abstract")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "compilationunit")!, rhs: [Symbol(rawValue: "BOF")!, Symbol(rawValue: "packagedeclaration")!, Symbol(rawValue: "importdeclaration")!, Symbol(rawValue: "EOF")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "native")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "void")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "abstract")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "public")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "interface")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "final")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "class")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "protected")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "static")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "public")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "short")!: 163
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "]")!: 244
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "andexpression")!, rhs: [Symbol(rawValue: "equalityexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "andexpression")!, rhs: [Symbol(rawValue: "equalityexpression")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "andexpression")!, rhs: [Symbol(rawValue: "equalityexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "andexpression")!, rhs: [Symbol(rawValue: "equalityexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "andexpression")!, rhs: [Symbol(rawValue: "equalityexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "andexpression")!, rhs: [Symbol(rawValue: "equalityexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "andexpression")!, rhs: [Symbol(rawValue: "equalityexpression")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "==")!: 241,
+               Symbol(rawValue: "!=")!: 206
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "booleanliteral")!: 202
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "fieldaccess")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "id")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "type")!, rhs: [Symbol(rawValue: "referencetype")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "(")!: 172,
+               Symbol(rawValue: "[")!: 179
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "arraycreationexpression")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "expressionstatement")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "native")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "void")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "abstract")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "public")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "interface")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "final")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "class")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "protected")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "static")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "protected")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "numerictype")!, rhs: [Symbol(rawValue: "integraltype")!]),
+               Symbol(rawValue: "id")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "numerictype")!, rhs: [Symbol(rawValue: "integraltype")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "numerictype")!, rhs: [Symbol(rawValue: "integraltype")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementexpression")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementexpression")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementexpression")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "id")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "type")!, rhs: [Symbol(rawValue: "primitivetype")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "[")!: 5
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "abstract")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!]),
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!]),
+               Symbol(rawValue: "native")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!]),
+               Symbol(rawValue: "void")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!]),
+               Symbol(rawValue: "public")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!]),
+               Symbol(rawValue: "final")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!]),
+               Symbol(rawValue: "static")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!]),
+               Symbol(rawValue: "protected")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classbodydeclaration")!, rhs: [Symbol(rawValue: "constructordeclaration")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "constructorbody")!: 346
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "classinstancecreationexpression")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "unaryexpression")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "whilestatement")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "(")!: 61
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "assignmentexpression")!, rhs: [Symbol(rawValue: "assignment")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "assignmentexpression")!, rhs: [Symbol(rawValue: "assignment")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "assignmentexpression")!, rhs: [Symbol(rawValue: "assignment")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "assignmentexpression")!, rhs: [Symbol(rawValue: "assignment")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "EOF")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "interfacedeclaration")!, rhs: [Symbol(rawValue: "interface")!, Symbol(rawValue: "id")!, Symbol(rawValue: "extendsinterfaces")!, Symbol(rawValue: "interfacebody")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "statementwithouttrailingsubstatement")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "id")!: 344
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statement")!, rhs: [Symbol(rawValue: "forstatement")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "primary")!: 55,
+               Symbol(rawValue: "castexpression")!: 58,
+               Symbol(rawValue: "this")!: 29,
+               Symbol(rawValue: "classinstancecreationexpression")!: 19,
+               Symbol(rawValue: "integerliteral")!: 7,
+               Symbol(rawValue: "unaryexpressionnotplusminus")!: 126,
+               Symbol(rawValue: "fieldaccess")!: 8,
+               Symbol(rawValue: "!")!: 33,
+               Symbol(rawValue: "name")!: 140,
+               Symbol(rawValue: "new")!: 40,
+               Symbol(rawValue: "-")!: 28,
+               Symbol(rawValue: "arraycreationexpression")!: 11,
+               Symbol(rawValue: "primarynonewarray")!: 57,
+               Symbol(rawValue: "arrayaccess")!: 30,
+               Symbol(rawValue: "methodinvocation")!: 86,
+               Symbol(rawValue: "literal")!: 53,
+               Symbol(rawValue: "postfixexpression")!: 124,
+               Symbol(rawValue: "unaryexpression")!: 314,
+               Symbol(rawValue: "(")!: 32
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "this")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "arrayaccess")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "returnstatement")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "byte")!: 4,
+               Symbol(rawValue: "equalityexpression")!: 6,
+               Symbol(rawValue: "andexpression")!: 142,
+               Symbol(rawValue: "relationalexpression")!: 35,
+               Symbol(rawValue: "expression")!: 112,
+               Symbol(rawValue: "assignmentexpression")!: 81,
+               Symbol(rawValue: "primitivetype")!: 294,
+               Symbol(rawValue: "conditionalandexpression")!: 88,
+               Symbol(rawValue: "name")!: 59,
+               Symbol(rawValue: "integraltype")!: 14,
+               Symbol(rawValue: "|")!: 120,
+               Symbol(rawValue: "assignment")!: 23,
+               Symbol(rawValue: "boolean")!: 43,
+               Symbol(rawValue: "conditionalexpression")!: 115,
+               Symbol(rawValue: "exclusiveorexpression")!: 75,
+               Symbol(rawValue: "inclusiveorexpression")!: 82,
+               Symbol(rawValue: "conditionalorexpression")!: 125,
+               Symbol(rawValue: "numerictype")!: 65
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "primary")!: 55,
+               Symbol(rawValue: "castexpression")!: 58,
+               Symbol(rawValue: "this")!: 29,
+               Symbol(rawValue: "integerliteral")!: 7,
+               Symbol(rawValue: "unaryexpressionnotplusminus")!: 126,
+               Symbol(rawValue: "classinstancecreationexpression")!: 19,
+               Symbol(rawValue: "!")!: 33,
+               Symbol(rawValue: "fieldaccess")!: 8,
+               Symbol(rawValue: "name")!: 140,
+               Symbol(rawValue: "new")!: 40,
+               Symbol(rawValue: "primarynonewarray")!: 57,
+               Symbol(rawValue: "arraycreationexpression")!: 11,
+               Symbol(rawValue: "-")!: 28,
+               Symbol(rawValue: "arrayaccess")!: 30,
+               Symbol(rawValue: "methodinvocation")!: 86,
+               Symbol(rawValue: "literal")!: 53,
+               Symbol(rawValue: "postfixexpression")!: 124,
+               Symbol(rawValue: "unaryexpression")!: 255,
+               Symbol(rawValue: "(")!: 32
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ";")!: 341
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "equalityexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "equalityexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "equalityexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "equalityexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "equalityexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "equalityexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "equalityexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "equalityexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "equalityexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ">=")!: 117,
+               Symbol(rawValue: ">")!: 106,
+               Symbol(rawValue: "<")!: 107,
+               Symbol(rawValue: "instanceof")!: 37,
+               Symbol(rawValue: "<=")!: 79
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "castexpression")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "primitivetype")!, Symbol(rawValue: ")")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "byte")!: 4,
+               Symbol(rawValue: "integraltype")!: 14,
+               Symbol(rawValue: "referencetype")!: 147,
+               Symbol(rawValue: "primitivetype")!: 66,
+               Symbol(rawValue: "boolean")!: 43,
+               Symbol(rawValue: "arraytype")!: 174,
+               Symbol(rawValue: "name")!: 91,
+               Symbol(rawValue: "classorinterfacetype")!: 99,
+               Symbol(rawValue: "numerictype")!: 65
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ";")!: 138
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "equalityexpression")!: 6,
+               Symbol(rawValue: "andexpression")!: 142,
+               Symbol(rawValue: "relationalexpression")!: 35,
+               Symbol(rawValue: "expression")!: 204,
+               Symbol(rawValue: "assignmentexpression")!: 81,
+               Symbol(rawValue: "conditionalandexpression")!: 88,
+               Symbol(rawValue: "assignment")!: 23,
+               Symbol(rawValue: "|")!: 120,
+               Symbol(rawValue: "conditionalexpression")!: 115,
+               Symbol(rawValue: "exclusiveorexpression")!: 75,
+               Symbol(rawValue: "argumentlist")!: 226,
+               Symbol(rawValue: "inclusiveorexpression")!: 82,
+               Symbol(rawValue: "conditionalorexpression")!: 125,
+               Symbol(rawValue: ")")!: 312
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "numerictype")!: 65,
+               Symbol(rawValue: "integraltype")!: 14,
+               Symbol(rawValue: "primitivetype")!: 247,
+               Symbol(rawValue: "boolean")!: 43,
+               Symbol(rawValue: "classtype")!: 333,
+               Symbol(rawValue: "name")!: 91,
+               Symbol(rawValue: "classorinterfacetype")!: 116,
+               Symbol(rawValue: "byte")!: 4
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "abstract")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "native")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "void")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "public")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "interface")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "final")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "static")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "class")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "protected")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifiers")!, rhs: [Symbol(rawValue: "modifier")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "EOF")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "interfacedeclaration")!, rhs: [Symbol(rawValue: "interface")!, Symbol(rawValue: "id")!, Symbol(rawValue: "interfacebody")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primitivetype")!, rhs: [Symbol(rawValue: "boolean")!]),
+               Symbol(rawValue: "id")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primitivetype")!, rhs: [Symbol(rawValue: "boolean")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primitivetype")!, rhs: [Symbol(rawValue: "boolean")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexprs")!, Symbol(rawValue: "dimexpr")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "(")!: 211
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexprs")!, rhs: [Symbol(rawValue: "dimexpr")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "abstract")!: 1,
+               Symbol(rawValue: "native")!: 54,
+               Symbol(rawValue: "public")!: 3,
+               Symbol(rawValue: "modifier")!: 160,
+               Symbol(rawValue: "interface")!: 84,
+               Symbol(rawValue: "final")!: 146,
+               Symbol(rawValue: "protected")!: 13,
+               Symbol(rawValue: "static")!: 105,
+               Symbol(rawValue: "class")!: 326
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "(")!: 273
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "]")!: 149
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "byte")!: 4,
+               Symbol(rawValue: "void")!: 165,
+               Symbol(rawValue: "public")!: 3,
+               Symbol(rawValue: "modifier")!: 160,
+               Symbol(rawValue: "primitivetype")!: 16,
+               Symbol(rawValue: "name")!: 91,
+               Symbol(rawValue: "classorinterfacetype")!: 99,
+               Symbol(rawValue: "native")!: 54,
+               Symbol(rawValue: "abstract")!: 1,
+               Symbol(rawValue: "type")!: 180,
+               Symbol(rawValue: "integraltype")!: 14,
+               Symbol(rawValue: "referencetype")!: 9,
+               Symbol(rawValue: "boolean")!: 43,
+               Symbol(rawValue: "constructordeclarator")!: 188,
+               Symbol(rawValue: "arraytype")!: 174,
+               Symbol(rawValue: "final")!: 146,
+               Symbol(rawValue: "static")!: 105,
+               Symbol(rawValue: "protected")!: 13,
+               Symbol(rawValue: "numerictype")!: 65
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "variabledeclarators")!, rhs: [Symbol(rawValue: "variabledeclarator")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "variabledeclarator")!, rhs: [Symbol(rawValue: "variabledeclaratorid")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "=")!: 171
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "literal")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "abstract")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "native")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "void")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "public")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "interface")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "final")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "protected")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "class")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "static")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "modifier")!, rhs: [Symbol(rawValue: "native")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "postfixexpression")!, rhs: [Symbol(rawValue: "primary")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ".")!: 26
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementexpression")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementexpression")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementexpression")!, rhs: [Symbol(rawValue: "methodinvocation")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primary")!, rhs: [Symbol(rawValue: "primarynonewarray")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "[")!: 282
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "unaryexpressionnotplusminus")!, rhs: [Symbol(rawValue: "castexpression")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "[")!: 49,
+               Symbol(rawValue: "dims")!: 260
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "variabledeclaratorid")!: 52,
+               Symbol(rawValue: "variabledeclarator")!: 51,
+               Symbol(rawValue: "id")!: 168,
+               Symbol(rawValue: "variabledeclarators")!: 190
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "relationalexpression")!: 35,
+               Symbol(rawValue: "andexpression")!: 142,
+               Symbol(rawValue: "assignment")!: 23,
+               Symbol(rawValue: "expression")!: 271,
+               Symbol(rawValue: "assignmentexpression")!: 81,
+               Symbol(rawValue: "|")!: 120,
+               Symbol(rawValue: "conditionalexpression")!: 115,
+               Symbol(rawValue: "conditionalandexpression")!: 88,
+               Symbol(rawValue: "exclusiveorexpression")!: 75,
+               Symbol(rawValue: "inclusiveorexpression")!: 82,
+               Symbol(rawValue: "conditionalorexpression")!: 125,
+               Symbol(rawValue: "equalityexpression")!: 6
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "block")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "variabledeclaratorid")!: 52,
+               Symbol(rawValue: "variabledeclarators")!: 225,
+               Symbol(rawValue: "variabledeclarator")!: 51,
+               Symbol(rawValue: "id")!: 145,
+               Symbol(rawValue: "methoddeclarator")!: 275
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ";")!: 176
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primitivetype")!, rhs: [Symbol(rawValue: "numerictype")!]),
+               Symbol(rawValue: "id")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primitivetype")!, rhs: [Symbol(rawValue: "numerictype")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primitivetype")!, rhs: [Symbol(rawValue: "numerictype")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "[")!: 5
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ";")!: 293
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forstatement")!, rhs: [Symbol(rawValue: "for")!, Symbol(rawValue: "(")!, Symbol(rawValue: ";")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ";")!, Symbol(rawValue: "forupdate")!, Symbol(rawValue: ")")!, Symbol(rawValue: "statement")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "byte")!: 4,
+               Symbol(rawValue: "this")!: 29,
+               Symbol(rawValue: "whilestatement")!: 21,
+               Symbol(rawValue: "statementwithouttrailingsubstatement")!: 25,
+               Symbol(rawValue: "integerliteral")!: 7,
+               Symbol(rawValue: "primitivetype")!: 16,
+               Symbol(rawValue: "name")!: 132,
+               Symbol(rawValue: "ifthenstatement")!: 158,
+               Symbol(rawValue: "expressionstatement")!: 12,
+               Symbol(rawValue: "forstatement")!: 27,
+               Symbol(rawValue: "localvariabledeclaration")!: 38,
+               Symbol(rawValue: "}")!: 94,
+               Symbol(rawValue: "new")!: 40,
+               Symbol(rawValue: "type")!: 60,
+               Symbol(rawValue: "block")!: 62,
+               Symbol(rawValue: "primarynonewarray")!: 57,
+               Symbol(rawValue: "statementexpression")!: 34,
+               Symbol(rawValue: "localvariabledeclarationstatement")!: 152,
+               Symbol(rawValue: "assignment")!: 141,
+               Symbol(rawValue: "statement")!: 173,
+               Symbol(rawValue: "ifthenelsestatement")!: 137,
+               Symbol(rawValue: "(")!: 78,
+               Symbol(rawValue: "if")!: 22,
+               Symbol(rawValue: "{")!: 69,
+               Symbol(rawValue: "primary")!: 118,
+               Symbol(rawValue: "numerictype")!: 65,
+               Symbol(rawValue: "blockstatement")!: 181,
+               Symbol(rawValue: "returnstatement")!: 31,
+               Symbol(rawValue: "classinstancecreationexpression")!: 15,
+               Symbol(rawValue: "fieldaccess")!: 8,
+               Symbol(rawValue: "blockstatements")!: 87,
+               Symbol(rawValue: "for")!: 48,
+               Symbol(rawValue: "emptystatement")!: 72,
+               Symbol(rawValue: "classorinterfacetype")!: 99,
+               Symbol(rawValue: "arraycreationexpression")!: 11,
+               Symbol(rawValue: "return")!: 92,
+               Symbol(rawValue: "integraltype")!: 14,
+               Symbol(rawValue: "referencetype")!: 9,
+               Symbol(rawValue: "methodinvocation")!: 56,
+               Symbol(rawValue: "literal")!: 53,
+               Symbol(rawValue: "boolean")!: 43,
+               Symbol(rawValue: "arraytype")!: 174,
+               Symbol(rawValue: "arrayaccess")!: 30,
+               Symbol(rawValue: ";")!: 74
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "primary")!: 118,
+               Symbol(rawValue: "this")!: 29,
+               Symbol(rawValue: "integerliteral")!: 7,
+               Symbol(rawValue: "classinstancecreationexpression")!: 15,
+               Symbol(rawValue: "fieldaccess")!: 8,
+               Symbol(rawValue: "name")!: 10,
+               Symbol(rawValue: "primarynonewarray")!: 57,
+               Symbol(rawValue: "new")!: 40,
+               Symbol(rawValue: "arraycreationexpression")!: 11,
+               Symbol(rawValue: "assignment")!: 141,
+               Symbol(rawValue: "arrayaccess")!: 30,
+               Symbol(rawValue: "methodinvocation")!: 56,
+               Symbol(rawValue: "literal")!: 53,
+               Symbol(rawValue: "statementexpression")!: 322,
+               Symbol(rawValue: "(")!: 210
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "relationalexpression")!, rhs: [Symbol(rawValue: "relationalexpression")!, Symbol(rawValue: "<=")!, Symbol(rawValue: "additiveexpression")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "-")!: 189,
+               Symbol(rawValue: "+")!: 187
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "statementwithouttrailingsubstatement")!, rhs: [Symbol(rawValue: "emptystatement")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ")")!: 329
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "emptystatement")!, rhs: [Symbol(rawValue: ";")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "inclusiveorexpression")!, rhs: [Symbol(rawValue: "exclusiveorexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "inclusiveorexpression")!, rhs: [Symbol(rawValue: "exclusiveorexpression")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "inclusiveorexpression")!, rhs: [Symbol(rawValue: "exclusiveorexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "inclusiveorexpression")!, rhs: [Symbol(rawValue: "exclusiveorexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "inclusiveorexpression")!, rhs: [Symbol(rawValue: "exclusiveorexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "inclusiveorexpression")!, rhs: [Symbol(rawValue: "exclusiveorexpression")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forinit")!, rhs: [Symbol(rawValue: "statementexpressionlist")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ",")!: 70
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "EOF")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "typedeclaration")!, rhs: [Symbol(rawValue: "interfacedeclaration")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "andexpression")!: 142,
+               Symbol(rawValue: "assignment")!: 23,
+               Symbol(rawValue: "|")!: 120,
+               Symbol(rawValue: "expression")!: 73,
+               Symbol(rawValue: "assignmentexpression")!: 81,
+               Symbol(rawValue: "relationalexpression")!: 35,
+               Symbol(rawValue: "conditionalexpression")!: 115,
+               Symbol(rawValue: "conditionalandexpression")!: 88,
+               Symbol(rawValue: "exclusiveorexpression")!: 75,
+               Symbol(rawValue: "inclusiveorexpression")!: 82,
+               Symbol(rawValue: "conditionalorexpression")!: 125,
+               Symbol(rawValue: "equalityexpression")!: 6
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "additiveexpression")!: 71,
+               Symbol(rawValue: "primary")!: 55,
+               Symbol(rawValue: "castexpression")!: 58,
+               Symbol(rawValue: "this")!: 29,
+               Symbol(rawValue: "classinstancecreationexpression")!: 19,
+               Symbol(rawValue: "unaryexpressionnotplusminus")!: 126,
+               Symbol(rawValue: "!")!: 33,
+               Symbol(rawValue: "integerliteral")!: 7,
+               Symbol(rawValue: "fieldaccess")!: 8,
+               Symbol(rawValue: "name")!: 140,
+               Symbol(rawValue: "primarynonewarray")!: 57,
+               Symbol(rawValue: "-")!: 28,
+               Symbol(rawValue: "new")!: 40,
+               Symbol(rawValue: "arraycreationexpression")!: 11,
+               Symbol(rawValue: "arrayaccess")!: 30,
+               Symbol(rawValue: "methodinvocation")!: 86,
+               Symbol(rawValue: "literal")!: 53,
+               Symbol(rawValue: "multiplicativeexpression")!: 80,
+               Symbol(rawValue: "unaryexpression")!: 20,
+               Symbol(rawValue: "postfixexpression")!: 124,
+               Symbol(rawValue: "(")!: 32
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "additiveexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "/")!: 130,
+               Symbol(rawValue: "%")!: 127,
+               Symbol(rawValue: "*")!: 128
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "expression")!, rhs: [Symbol(rawValue: "assignmentexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "expression")!, rhs: [Symbol(rawValue: "assignmentexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "expression")!, rhs: [Symbol(rawValue: "assignmentexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "expression")!, rhs: [Symbol(rawValue: "assignmentexpression")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalandexpression")!, rhs: [Symbol(rawValue: "inclusiveorexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalandexpression")!, rhs: [Symbol(rawValue: "inclusiveorexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalandexpression")!, rhs: [Symbol(rawValue: "inclusiveorexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalandexpression")!, rhs: [Symbol(rawValue: "inclusiveorexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalandexpression")!, rhs: [Symbol(rawValue: "inclusiveorexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalandexpression")!, rhs: [Symbol(rawValue: "inclusiveorexpression")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "id")!: 269
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "id")!: 237
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "EOF")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classdeclaration")!, rhs: [Symbol(rawValue: "class")!, Symbol(rawValue: "id")!, Symbol(rawValue: "interfaces")!, Symbol(rawValue: "classbody")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "methodinvocation")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ";")!: 74,
+               Symbol(rawValue: "this")!: 29,
+               Symbol(rawValue: "whilestatement")!: 21,
+               Symbol(rawValue: "integerliteral")!: 7,
+               Symbol(rawValue: "primitivetype")!: 16,
+               Symbol(rawValue: "statementwithouttrailingsubstatement")!: 25,
+               Symbol(rawValue: "name")!: 132,
+               Symbol(rawValue: "ifthenstatement")!: 158,
+               Symbol(rawValue: "localvariabledeclarationstatement")!: 152,
+               Symbol(rawValue: "expressionstatement")!: 12,
+               Symbol(rawValue: "localvariabledeclaration")!: 38,
+               Symbol(rawValue: "new")!: 40,
+               Symbol(rawValue: "forstatement")!: 27,
+               Symbol(rawValue: "type")!: 60,
+               Symbol(rawValue: "block")!: 62,
+               Symbol(rawValue: "assignment")!: 141,
+               Symbol(rawValue: "statementexpression")!: 34,
+               Symbol(rawValue: "primarynonewarray")!: 57,
+               Symbol(rawValue: "}")!: 332,
+               Symbol(rawValue: "statement")!: 173,
+               Symbol(rawValue: "ifthenelsestatement")!: 137,
+               Symbol(rawValue: "returnstatement")!: 31,
+               Symbol(rawValue: "if")!: 22,
+               Symbol(rawValue: "numerictype")!: 65,
+               Symbol(rawValue: "primary")!: 118,
+               Symbol(rawValue: "{")!: 69,
+               Symbol(rawValue: "blockstatement")!: 194,
+               Symbol(rawValue: "(")!: 78,
+               Symbol(rawValue: "classinstancecreationexpression")!: 15,
+               Symbol(rawValue: "fieldaccess")!: 8,
+               Symbol(rawValue: "for")!: 48,
+               Symbol(rawValue: "emptystatement")!: 72,
+               Symbol(rawValue: "classorinterfacetype")!: 99,
+               Symbol(rawValue: "arraycreationexpression")!: 11,
+               Symbol(rawValue: "return")!: 92,
+               Symbol(rawValue: "integraltype")!: 14,
+               Symbol(rawValue: "referencetype")!: 9,
+               Symbol(rawValue: "arrayaccess")!: 30,
+               Symbol(rawValue: "literal")!: 53,
+               Symbol(rawValue: "boolean")!: 43,
+               Symbol(rawValue: "methodinvocation")!: 56,
+               Symbol(rawValue: "arraytype")!: 174,
+               Symbol(rawValue: "byte")!: 4
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalorexpression")!, rhs: [Symbol(rawValue: "conditionalandexpression")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalorexpression")!, rhs: [Symbol(rawValue: "conditionalandexpression")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalorexpression")!, rhs: [Symbol(rawValue: "conditionalandexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalorexpression")!, rhs: [Symbol(rawValue: "conditionalandexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "conditionalorexpression")!, rhs: [Symbol(rawValue: "conditionalandexpression")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "&&")!: 167
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "compilationunit")!, rhs: [Symbol(rawValue: "BOF")!, Symbol(rawValue: "typedeclaration")!, Symbol(rawValue: "EOF")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "dimexpr")!, rhs: [Symbol(rawValue: "[")!, Symbol(rawValue: "expression")!, Symbol(rawValue: "]")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "id")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "classorinterfacetype")!, rhs: [Symbol(rawValue: "name")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "equalityexpression")!: 6,
+               Symbol(rawValue: "relationalexpression")!: 35,
+               Symbol(rawValue: "andexpression")!: 142,
+               Symbol(rawValue: "expression")!: 217,
+               Symbol(rawValue: "assignmentexpression")!: 81,
+               Symbol(rawValue: "conditionalandexpression")!: 88,
+               Symbol(rawValue: "assignment")!: 23,
+               Symbol(rawValue: "|")!: 120,
+               Symbol(rawValue: "conditionalexpression")!: 115,
+               Symbol(rawValue: "exclusiveorexpression")!: 75,
+               Symbol(rawValue: "inclusiveorexpression")!: 82,
+               Symbol(rawValue: "conditionalorexpression")!: 125,
+               Symbol(rawValue: ";")!: 178
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "whilestatement")!: 21,
+               Symbol(rawValue: "this")!: 29,
+               Symbol(rawValue: "statementwithouttrailingsubstatement")!: 25,
+               Symbol(rawValue: "integerliteral")!: 7,
+               Symbol(rawValue: "name")!: 10,
+               Symbol(rawValue: "ifthenstatement")!: 158,
+               Symbol(rawValue: "expressionstatement")!: 12,
+               Symbol(rawValue: "forstatement")!: 27,
+               Symbol(rawValue: "new")!: 40,
+               Symbol(rawValue: "primarynonewarray")!: 57,
+               Symbol(rawValue: "block")!: 62,
+               Symbol(rawValue: "assignment")!: 141,
+               Symbol(rawValue: "statementexpression")!: 34,
+               Symbol(rawValue: "statement")!: 148,
+               Symbol(rawValue: "ifthenelsestatement")!: 137,
+               Symbol(rawValue: "returnstatement")!: 31,
+               Symbol(rawValue: "if")!: 22,
+               Symbol(rawValue: "{")!: 69,
+               Symbol(rawValue: "primary")!: 118,
+               Symbol(rawValue: "(")!: 78,
+               Symbol(rawValue: "classinstancecreationexpression")!: 15,
+               Symbol(rawValue: "statementnoshortif")!: 119,
+               Symbol(rawValue: "fieldaccess")!: 8,
+               Symbol(rawValue: "for")!: 48,
+               Symbol(rawValue: "emptystatement")!: 72,
+               Symbol(rawValue: "arraycreationexpression")!: 11,
+               Symbol(rawValue: "return")!: 92,
+               Symbol(rawValue: "arrayaccess")!: 30,
+               Symbol(rawValue: "methodinvocation")!: 56,
+               Symbol(rawValue: "literal")!: 53,
+               Symbol(rawValue: ";")!: 74
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "if")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "void")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "static")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "public")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "integerliteral")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "this")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "for")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "new")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "}")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "abstract")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "return")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "native")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "boolean")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "final")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "protected")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "(")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "{")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!]),
+               Symbol(rawValue: "byte")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "block")!, rhs: [Symbol(rawValue: "{")!, Symbol(rawValue: "}")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "forupdate")!, rhs: [Symbol(rawValue: "statementexpressionlist")!])
+            ],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ",")!: 70
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "*")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "/")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "+")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "-")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: "%")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "multiplicativeexpression")!, rhs: [Symbol(rawValue: "multiplicativeexpression")!, Symbol(rawValue: "*")!, Symbol(rawValue: "unaryexpression")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: ")")!: 306
+            ]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "abstract")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!]),
+               Symbol(rawValue: "native")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!]),
+               Symbol(rawValue: "public")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!]),
+               Symbol(rawValue: "EOF")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!]),
+               Symbol(rawValue: "interface")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!]),
+               Symbol(rawValue: "final")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!]),
+               Symbol(rawValue: "protected")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!]),
+               Symbol(rawValue: "class")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!]),
+               Symbol(rawValue: "static")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!]),
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "importdeclaration")!, rhs: [Symbol(rawValue: "singletypeimportdeclaration")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: ";")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: ">=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "id")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: ">")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "!=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "instanceof")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "<")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "<=")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: ",")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "]")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "==")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "&&")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: "||")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!]),
+               Symbol(rawValue: ")")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "referencetype")!, rhs: [Symbol(rawValue: "classorinterfacetype")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "[")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ")")!]),
+               Symbol(rawValue: ".")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "primarynonewarray")!, rhs: [Symbol(rawValue: "(")!, Symbol(rawValue: "expression")!, Symbol(rawValue: ")")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [
+               Symbol(rawValue: "EOF")!: ParseTable.ProductionRule(lhs: Symbol(rawValue: "typedeclaration")!, rhs: [Symbol(rawValue: "classdeclaration")!])
+            ],
+            lookaheadToNextStateMap: [:]
+         ),
+         ParseTable.State(
+            lookaheadToProductionRuleMap: [:],
+            lookaheadToNextStateMap: [
+               Symbol(rawValue: "id")!: 45,
+               Symbol(rawValue: "methoddeclarator")!: 298
+            ]
+         )
+      ]
+   }
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-44074.swift.gyb b/validation-test/Sema/type_checker_perf/slow/issue-44074.swift.gyb
new file mode 100644
index 0000000000000..9eee3c8a1d404
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-44074.swift.gyb
@@ -0,0 +1,11 @@
+// RUN: %scale-test --invert-result --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+func slow() {
+  let a = [1]
+  let x = [
+%for i in range(0, N):
+    a.lazy.map({$0 + 1}),
+%end
+  ]
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-49476.swift b/validation-test/Sema/type_checker_perf/slow/issue-49476.swift
new file mode 100644
index 0000000000000..2eefe002e6adc
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-49476.swift
@@ -0,0 +1,12 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=1000
+
+// https://github.com/swiftlang/swift/issues/49476
+
+// This is invalid, because offset and index have mismatched types
+
+func slow() {
+  let offset: Double = 5.0
+  let index: Int = 10
+  let angle = (180.0 - offset + index * 5.0) * .pi / 18
+  // expected-error@-1{{reasonable time}}
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-52532.swift b/validation-test/Sema/type_checker_perf/slow/issue-52532.swift
new file mode 100644
index 0000000000000..aa2ad2c438de4
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-52532.swift
@@ -0,0 +1,21 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -typecheck -verify -solver-scope-threshold=1000
+// REQUIRES: objc_interop
+
+import Foundation
+
+// https://github.com/swiftlang/swift/issues/52532
+
+func slow() {
+  let itemsPerRow = 10
+  let size: CGFloat = 20
+  let margin: CGFloat = 10
+  // expected-error@+1{{reasonable time}}
+  let foo = (0..<100)
+    .map { (row: CGFloat($0 / itemsPerRow), col: CGFloat($0 % itemsPerRow)) }
+    .map {
+      CGRect(x: $0.col * (size + margin) + margin,
+             y: $0.row * (size + margin) + margin,
+             width: size,
+             height: size)
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-52861-2.swift b/validation-test/Sema/type_checker_perf/slow/issue-52861-2.swift
new file mode 100644
index 0000000000000..281097bc4e497
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-52861-2.swift
@@ -0,0 +1,15 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=1000
+
+// Further down in https://github.com/swiftlang/swift/issues/52861:
+
+// This type checks in ~300ms with the default limits, but we make it fail sooner.
+
+func slow() {
+  let u = SIMD2<Float>(0, 1)
+  let v = SIMD2<Float>(1, 2)
+  let r = [ // expected-error{{reasonable time}}
+      2*u + 3*v,
+      4*u + 5*v
+  ]
+  print(r)
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-52861.swift b/validation-test/Sema/type_checker_perf/slow/issue-52861.swift
new file mode 100644
index 0000000000000..3063ae84654bf
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-52861.swift
@@ -0,0 +1,16 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=1000
+// REQUIRES: objc_interop
+
+// https://github.com/swiftlang/swift/issues/52861
+
+// This type checks in ~800ms with the default limits, but we make it fail sooner.
+
+import simd
+
+func test(_ p0: float2, _ p1: float2, _ p2: float2, _ p3: float2) {
+    let i = 3*(-p0 + 3*p1) - (3*p2 + p3) // expected-error{{reasonable time}}
+    let j = 6*(p0 - 2*p1 + p2) // expected-error{{reasonable time}}
+    let k = 3*(p1 - p0)
+    print(i, j, k)
+}
+test(float2(0.1, 1.2), float2(2.3, 3.4), float2(4.5, 5.6), float2(6.7, 7.8))
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-53006.swift b/validation-test/Sema/type_checker_perf/slow/issue-53006.swift
new file mode 100644
index 0000000000000..118b448479384
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-53006.swift
@@ -0,0 +1,8 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=1000
+
+// https://github.com/swiftlang/swift/issues/53006
+
+func extractBits(from word: UInt64, offset: Int, numBits: Int) -> UInt {
+    return UInt((word >> offset) & ((1 << numBits) - 1) & ((1 << numBits) - 1) & ((1 << numBits) - 1))
+    // expected-error@-1 {{reasonable time}}
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-53523.swift b/validation-test/Sema/type_checker_perf/slow/issue-53523.swift
new file mode 100644
index 0000000000000..e8a11c7684ac4
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-53523.swift
@@ -0,0 +1,10 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=1000
+
+// https://github.com/swiftlang/swift/issues/53523
+
+// This is invalid: we're mixing Double and Int.
+
+public func slow(d: Double, n: Int) {
+  return d * 1.0 + 1.0 / n + d / d
+  // expected-error@-1 {{reasonable time}}
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-54143-1.swift b/validation-test/Sema/type_checker_perf/slow/issue-54143-1.swift
new file mode 100644
index 0000000000000..842e0e743748e
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-54143-1.swift
@@ -0,0 +1,34 @@
+// RUN: %target-typecheck-verify-swift
+// REQUIRES: objc_interop
+
+// https://github.com/swiftlang/swift/issues/54143
+
+import Foundation
+import CoreGraphics
+
+class UIViewController {
+  var view: UIView
+  var preferredContentSize: CGSize
+
+  init() { fatalError() }
+}
+
+class UIView {
+  var bounds: CGRect
+  var frame: CGRect
+  var subviews: [UIView] = []
+
+  init() { fatalError() }
+}
+
+// This is invalid, because there is no one-argument form of reduce()
+
+class SomeViewController: UIViewController {
+    private func updatePreferredContentSize() {
+        // expected-error@+1 {{failed to produce diagnostic}}
+        preferredContentSize = CGSize(
+            width: view.bounds.width,
+            height: (view.subviews.map { $0.frame.height }.reduce(+) ?? 0) + 20.0
+        )
+    }
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-54830.swift.gyb b/validation-test/Sema/type_checker_perf/slow/issue-54830.swift.gyb
new file mode 100644
index 0000000000000..693412d6af90f
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-54830.swift.gyb
@@ -0,0 +1,13 @@
+// RUN: %scale-test --invert-result --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/54830
+
+func slow() {
+  let bitmask = [
+    1<<0, 1<<0,
+%for i in range(0, N):
+    1<<1, 1<<1,
+%end
+  ]
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-55762.swift.gyb b/validation-test/Sema/type_checker_perf/slow/issue-55762.swift.gyb
new file mode 100644
index 0000000000000..a202f51447604
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-55762.swift.gyb
@@ -0,0 +1,16 @@
+// RUN: %scale-test --invert-result --begin 1 --end 5 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/55762
+
+struct S {
+  var data: [Int16]
+  var idx = 0
+
+  func f() {
+    let _ = UInt64(self.data[self.idx]) << 56
+%for i in range(0, N):
+          | UInt64(self.data[self.idx + 1]) << 48
+%end
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-58051.swift.gyb b/validation-test/Sema/type_checker_perf/slow/issue-58051.swift.gyb
new file mode 100644
index 0000000000000..93c1f51ba805c
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-58051.swift.gyb
@@ -0,0 +1,19 @@
+// RUN: %scale-test --invert-result --begin 1 --end 6 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
+// REQUIRES: asserts, no_asan
+
+// https://github.com/swiftlang/swift/issues/58051
+
+struct Date {}
+
+struct S {
+  var x: Date?
+}
+
+extension S {
+  var y: Date? {
+    x
+%for i in range(0, N):
+      ?? x
+%end
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-60320.swift b/validation-test/Sema/type_checker_perf/slow/issue-60320.swift
new file mode 100644
index 0000000000000..1768bf9c90bb7
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-60320.swift
@@ -0,0 +1,22 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=10000
+// This also fails with the default limit.
+
+// https://github.com/swiftlang/swift/issues/60320
+
+struct MyType {}
+func *(_: Double, _: MyType) -> MyType {}
+// func *(_: MyType, _: Double) -> MyType {}
+func +(_: MyType, _: MyType) -> MyType {}
+
+func slow() {
+  let d: Double
+  let state: MyType
+  let k1: MyType
+  let k2: MyType
+  let k3: MyType
+  let k4: MyType
+
+  // This is invalid because of the missing overload commented out above
+  let result = state + (1.0/6) * (k1 + 2*k2 + 2*k3 + k4) * d
+  // expected-error@-1 {{reasonable}}
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-62356.swift b/validation-test/Sema/type_checker_perf/slow/issue-62356.swift
new file mode 100644
index 0000000000000..f52bd1caf407b
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-62356.swift
@@ -0,0 +1,38 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=10000
+// This also fails with the default limit.
+
+// https://github.com/swiftlang/swift/issues/62356
+
+func sort4<Value,
+           Property1: Comparable,
+           Property2: Comparable,
+           Property3: Comparable,
+           Property4: Comparable>(
+    _ a: Value,
+    _ b: Value,
+    prop1: KeyPath<Value, Property1>,
+    comparator1: (Property1, Property1) -> Bool,
+    prop2: KeyPath<Value, Property2>,
+    comparator2: (Property2, Property2) -> Bool,
+    prop3: KeyPath<Value, Property3>,
+    comparator3: (Property3, Property3) -> Bool,
+    prop4: KeyPath<Value, Property4>,
+    comparator4: (Property4, Property4) -> Bool
+) -> Bool { return false }
+
+struct Foo {
+    static func sort(_ lhs: Self, _ rhs: Self) -> Bool {
+        // expected-error@+1 {{reasonable}}
+        sort4(lhs, rhs,
+              prop1: \.a, comparator1: <,
+              prop2: \.b, comparator2: <,
+              prop3: \.c, comparator3: <,
+              prop4: \.d, comparator4: <)
+    }
+
+    var a: Int
+    var b: Int
+    var c: Int
+    var d: Int
+}
+
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-62778.swift b/validation-test/Sema/type_checker_perf/slow/issue-62778.swift
new file mode 100644
index 0000000000000..bb8d74533c14a
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-62778.swift
@@ -0,0 +1,12 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=10000
+// This also fails with the default limit.
+
+// https://github.com/swiftlang/swift/issues/62778
+
+// This is invalid; we're applying | to UInt vs Int.
+
+func slow() {
+  let pieces = [1, 2, 3, 4]
+  let _ = (UInt(pieces[0]) << 24) | (UInt(pieces[1]) << 16) | (UInt(pieces[2]) << 8) | pieces[3]
+  // expected-error@-1 {{reasonable time}}
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-69277.swift b/validation-test/Sema/type_checker_perf/slow/issue-69277.swift
new file mode 100644
index 0000000000000..757b83009caf7
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-69277.swift
@@ -0,0 +1,23 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=10000
+// This also fails with the default limit.
+
+// REQUIRES: objc_interop
+
+// https://github.com/swiftlang/swift/issues/69277
+
+import Foundation
+
+struct Monster {
+    var weaponP1: Int? { nil }
+    var weaponP2: Int? { nil }
+    var weaponP3: Int? { nil }
+}
+
+func slow() {
+  // expected-error@+1 {{reasonable time}}
+  let predicate = #Predicate<Monster> { monster in
+      ((monster.weaponP1 == 1) &&
+       (monster.weaponP2 == 2) &&
+       (monster.weaponP3 == 3))
+  }
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/issue-73885.swift b/validation-test/Sema/type_checker_perf/slow/issue-73885.swift
new file mode 100644
index 0000000000000..b410b317615d3
--- /dev/null
+++ b/validation-test/Sema/type_checker_perf/slow/issue-73885.swift
@@ -0,0 +1,63 @@
+// RUN: %target-typecheck-verify-swift -solver-scope-threshold=10000
+// This also fails with the default limit.
+
+// https://github.com/swiftlang/swift/issues/73885
+
+enum Dimension: String {
+    case dim1
+    case dim2
+    case dim3
+    case dim4
+    case dim5
+    case dim6
+    case dim7
+    case dim8
+    case dim9
+    case dim10
+}
+
+struct Event {
+    let properties: [Dimension: String]
+    let foo: Int
+    let bar: String
+
+    init(properties: [Dimension: String] = [:], foo: Int? = nil) {
+        self.init(properties: properties, foo: foo, bar: "bar")
+    }
+
+    init(properties: [Dimension: String], foo: Int?, bar: String) {
+        self.properties = properties
+        self.foo = foo ?? 0
+        self.bar = bar
+    }
+}
+
+struct Foo {
+    let bar: Bar?
+    let baz: Int?
+}
+
+struct Bar {
+    let str: String
+    let bar: String?
+    let baz: Int
+    let bad: Double?
+    let isBar: Bool?
+}
+
+extension Event {
+    static func test1(foo: Foo) -> Event {
+        .init(properties: [  // expected-error {{reasonable time}}
+            .dim1: foo.bar?.bar,
+            .dim2: foo.bar?.baz,
+            .dim3: foo.bar?.bad,
+            .dim4: foo.bar?.isBar,
+            .dim5: foo.bar?.bar,
+            .dim6: foo.bar?.baz,
+            .dim7: foo.bar?.bad,
+            .dim8: foo.bar?.isBar,
+            .dim9: foo.bar?.bar,
+            .dim10: foo.bar.str
+        ].compactMapValues { $0 })
+    }
+}
diff --git a/validation-test/Sema/type_checker_perf/slow/nil_coalescing.swift.gyb b/validation-test/Sema/type_checker_perf/slow/nil_coalescing.swift.gyb
deleted file mode 100644
index 2ef5c8f16a3d7..0000000000000
--- a/validation-test/Sema/type_checker_perf/slow/nil_coalescing.swift.gyb
+++ /dev/null
@@ -1,9 +0,0 @@
-// RUN: %scale-test --invert-result --begin 1 --end 5 --step 1 --select NumLeafScopes %s
-// REQUIRES: asserts,no_asan
-
-func t(_ x: Int?) -> Int {
-  return (x ?? 0)
-%for i in range(1, N):
-         + (x ?? 0)
-%end
-}
diff --git a/validation-test/Sema/type_checker_perf/slow/nil_coalescing_dictionary_values.swift.gyb b/validation-test/Sema/type_checker_perf/slow/nil_coalescing_dictionary_values.swift.gyb
deleted file mode 100644
index 878c0a9dc78d1..0000000000000
--- a/validation-test/Sema/type_checker_perf/slow/nil_coalescing_dictionary_values.swift.gyb
+++ /dev/null
@@ -1,10 +0,0 @@
-// RUN: %scale-test --invert-result --begin 1 --end 8 --step 1 --select NumLeafScopes %s -Xfrontend=-typecheck
-// REQUIRES: asserts, no_asan
-
-let x: Int?
-
-let _ = [
-%for i in range(0, N):
-  "k" : x ?? 0,
-%end
-]
diff --git a/validation-test/Sema/type_checker_perf/slow/rdar22770433.swift b/validation-test/Sema/type_checker_perf/slow/rdar22770433.swift
deleted file mode 100644
index f063e685689de..0000000000000
--- a/validation-test/Sema/type_checker_perf/slow/rdar22770433.swift
+++ /dev/null
@@ -1,9 +0,0 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
-// REQUIRES: tools-release,no_asan
-
-func test(n: Int) -> Int {
-  // expected-error@+1 {{the compiler is unable to type-check this expression in reasonable time}}
-  return n == 0 ? 0 : (0..<n).reduce(0) {
-    ($0 > 0 && $1 % 2 == 0) ? ((($0 + $1) - ($0 + $1)) / ($1 - $0)) + (($0 + $1) / ($1 - $0)) : $0
-  }
-}
diff --git a/validation-test/Sema/type_checker_perf/slow/rdar26564101.swift b/validation-test/Sema/type_checker_perf/slow/rdar26564101.swift
index 09ca79329d7a3..e9e1d32c90f05 100644
--- a/validation-test/Sema/type_checker_perf/slow/rdar26564101.swift
+++ b/validation-test/Sema/type_checker_perf/slow/rdar26564101.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1 -solver-disable-shrink
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
 // REQUIRES: tools-release,no_asan
 // UNSUPPORTED: swift_test_mode_optimize_none && OS=linux-gnu
 
diff --git a/validation-test/Sema/type_checker_perf/slow/rdar31742586.swift b/validation-test/Sema/type_checker_perf/slow/rdar31742586.swift
deleted file mode 100644
index 0cc33ce8253cf..0000000000000
--- a/validation-test/Sema/type_checker_perf/slow/rdar31742586.swift
+++ /dev/null
@@ -1,7 +0,0 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
-// REQUIRES: tools-release,no_asan
-
-func rdar31742586() -> Double {
-  return -(1 + 2) + -(3 + 4) + 5 - (-(1 + 2) + -(3 + 4) + 5)
-  // expected-error@-1 {{the compiler is unable to type-check this expression in reasonable time}}
-}
diff --git a/validation-test/Sema/type_checker_perf/slow/rdar35213699.swift b/validation-test/Sema/type_checker_perf/slow/rdar35213699.swift
deleted file mode 100644
index 5d89ab1541a89..0000000000000
--- a/validation-test/Sema/type_checker_perf/slow/rdar35213699.swift
+++ /dev/null
@@ -1,8 +0,0 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
-// REQUIRES: tools-release,no_asan
-
-func test() {
-  let _: UInt = 1 * 2 + 3 * 4 + 5 * 6 + 7 * 8 + 9 * 10 + 11 * 12 + 13 * 14
-  // expected-error@-1 {{the compiler is unable to type-check this expression in reasonable time}}
-}
-
diff --git a/validation-test/Sema/type_checker_perf/slow/rdar91310777.swift b/validation-test/Sema/type_checker_perf/slow/rdar91310777.swift
deleted file mode 100644
index eb9dcbee848c8..0000000000000
--- a/validation-test/Sema/type_checker_perf/slow/rdar91310777.swift
+++ /dev/null
@@ -1,16 +0,0 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
-// REQUIRES: tools-release,no_asan
-
-func compute(_ cont: () -> Void) {}
-
-func test() {
-  compute {
-    let x = 42
-    compute {
-      print(x)
-      let v: UInt64 = UInt64((24 / UInt32(1)) + UInt32(0) - UInt32(0) - 24 / 42 - 42)
-      // expected-error@-1 {{the compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions}}
-      print(v)
-    }
-  }
-}
diff --git a/validation-test/Sema/type_checker_perf/slow/simd_scalar_multiple.swift.gyb b/validation-test/Sema/type_checker_perf/slow/simd_scalar_multiple.swift.gyb
deleted file mode 100644
index 497afd10785f5..0000000000000
--- a/validation-test/Sema/type_checker_perf/slow/simd_scalar_multiple.swift.gyb
+++ /dev/null
@@ -1,13 +0,0 @@
-// RUN: %scale-test --invert-result --begin 1 --end 5 --step 1 --select NumLeafScopes %s
-
-// REQUIRES: asserts,no_asan
-
-// Flaky is some simulator configurations
-// REQUIRES: OS=macosx
-
-func f(c: Float, a: SIMD2<Float>) -> SIMD2<Float> {
-  return (c * a)
-%for i in range(1, N):
-         + (c * a)
-%end
-}
diff --git a/validation-test/Sema/type_checker_perf/slow/swift_package_index_3.swift b/validation-test/Sema/type_checker_perf/slow/swift_package_index_3.swift
index 2327507262418..2ef209606305e 100644
--- a/validation-test/Sema/type_checker_perf/slow/swift_package_index_3.swift
+++ b/validation-test/Sema/type_checker_perf/slow/swift_package_index_3.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-scope-threshold=50000
+// RUN: %target-typecheck-verify-swift %s -solver-scope-threshold=50000
 // REQUIRES: tools-release,no_asan
 
 extension String {
diff --git a/validation-test/Sema/type_checker_perf/slow/swift_package_index_5.swift b/validation-test/Sema/type_checker_perf/slow/swift_package_index_5.swift
deleted file mode 100644
index e20ea384f9a5f..0000000000000
--- a/validation-test/Sema/type_checker_perf/slow/swift_package_index_5.swift
+++ /dev/null
@@ -1,13 +0,0 @@
-// RUN: %target-typecheck-verify-swift -solver-scope-threshold=1000 -swift-version 5
-// REQUIRES: tools-release,no_asan
-
-func g<T>(_: T) throws {
-    let _: T? = //expected-error {{the compiler is unable to type-check this expression in reasonable time}}
-        (try? f() as? T) ??
-        (try? f() as? T) ??
-        (try? f() as? T) ??
-        (try? f() as? T) ??
-        (try? f() as? T)
-}
-
-func f() throws -> Int { return 0 }
diff --git a/validation-test/Serialization/rdar151768216.swift b/validation-test/Serialization/rdar151768216.swift
new file mode 100644
index 0000000000000..63ff0137d16d5
--- /dev/null
+++ b/validation-test/Serialization/rdar151768216.swift
@@ -0,0 +1,18 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module %s -o %t -enable-experimental-feature LifetimeDependence
+
+// RUN: %target-swift-frontend -emit-sil %t/rdar151768216.swiftmodule \
+// RUN: -enable-experimental-feature LifetimeDependence
+
+// REQUIRES: swift_feature_LifetimeDependence
+
+// Ensure no crash
+extension Result {   
+  @inlinable
+  func castError(i: Int, j: Int, k: Int) -> Result<Success, Failure> {
+    return self.mapError { error in
+      return error
+    }   
+  }
+}
+
diff --git a/validation-test/compiler_crashers_2/005cd00fe6210934.swift b/validation-test/compiler_crashers_2/005cd00fe6210934.swift
new file mode 100644
index 0000000000000..58b9386b6e693
--- /dev/null
+++ b/validation-test/compiler_crashers_2/005cd00fe6210934.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::TupleContextualFailure::TupleContextualFailure(swift::constraints::Solution const&, swift::ContextualTypePurpose, swift::Type, swift::Type, llvm::ArrayRef<unsigned int>, swift::constraints::ConstraintLocator*)","signatureAssert":"Assertion failed: (getFromType()->is<TupleType>() && getToType()->is<TupleType>()), function TupleContextualFailure"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a< each b >->(Int, repeat each b)Float= a(
diff --git a/validation-test/compiler_crashers_2/012b9d4c832862a3.swift b/validation-test/compiler_crashers_2/012b9d4c832862a3.swift
new file mode 100644
index 0000000000000..f538bc88036ad
--- /dev/null
+++ b/validation-test/compiler_crashers_2/012b9d4c832862a3.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::rewriting::RewriteSystem::verifyRewriteRules(swift::rewriting::RewriteSystem::ValidityPolicy) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a { associatedtype b : Collection }
+struct c < d : Collection where d.Element : a,
+    e == d.Element.b.Element struct f < d : Collection where d.Element : a,
+    d.Element.b.Element == d.Index extension c where g == f<d>,
+    d : RangeReplaceableCollection
diff --git a/validation-test/compiler_crashers_2/014ab64f0056db9e.swift b/validation-test/compiler_crashers_2/014ab64f0056db9e.swift
new file mode 100644
index 0000000000000..3a6baf251275e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/014ab64f0056db9e.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"470b69c1","signature":"swift::constraints::ConstraintSystem::matchFunctionResultTypes(swift::Type, swift::Type, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (isDecl() && \"only makes sense for declaration choices\"), function getFunctionRefInfo"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+(a:-).a {
+}(<#expression#>)
diff --git a/validation-test/compiler_crashers_2/0208-issue-51259.swift b/validation-test/compiler_crashers_2/0208-issue-51259.swift
index be8a46b6771ac..9187710f7c9d1 100644
--- a/validation-test/compiler_crashers_2/0208-issue-51259.swift
+++ b/validation-test/compiler_crashers_2/0208-issue-51259.swift
@@ -1,3 +1,4 @@
+// {"kind":"emit-silgen","signature":"swift::Lowering::SILGenModule::useConformance(swift::ProtocolConformanceRef)"}
 // RUN: not --crash %target-swift-frontend -emit-ir %s
 // rdar://problem/65571199
 // UNSUPPORTED: asan
diff --git a/validation-test/compiler_crashers_2/025711440ba4dfcd.swift b/validation-test/compiler_crashers_2/025711440ba4dfcd.swift
new file mode 100644
index 0000000000000..f04777b4341a6
--- /dev/null
+++ b/validation-test/compiler_crashers_2/025711440ba4dfcd.swift
@@ -0,0 +1,13 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::TypePrinter::printArchetypeCommon(swift::Type, swift::GenericEnvironment*)","stackOverflow":true}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a: Collection where Element == b.Element! {
+  associatedtype b: Collection
+}
+protocol c {
+  associatedtype d: a where d.b: a, d.Element == Self
+}
+func e () {
+  func f<e : c>() {
+    e.g
+  }
+}
diff --git a/validation-test/compiler_crashers_2/029cff04b25b728d.swift b/validation-test/compiler_crashers_2/029cff04b25b728d.swift
new file mode 100644
index 0000000000000..1850f451acb6f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/029cff04b25b728d.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::TypeChecker::typeCheckStmtConditionElement(swift::StmtConditionElement&, bool&, swift::DeclContext*)","signatureAssert":"Assertion failed: (!elt.getPattern()->hasType() && \"the pattern binding condition is already type checked\"), function typeCheckPatternBindingStmtConditionElement"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+a guard let b let a = b
diff --git a/validation-test/compiler_crashers_2/033b407eb167aba5.swift b/validation-test/compiler_crashers_2/033b407eb167aba5.swift
new file mode 100644
index 0000000000000..1737431c8f729
--- /dev/null
+++ b/validation-test/compiler_crashers_2/033b407eb167aba5.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ExprRewriter::coerceCallArguments(swift::ArgumentList*, swift::AnyFunctionType*, swift::ConcreteDeclRef, swift::ApplyExpr*, swift::constraints::ConstraintLocatorBuilder, llvm::ArrayRef<swift::AppliedPropertyWrapper>)","signatureAssert":"Assertion failed: (param), function getDefaultArgOwner"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<b, each c>(body : (repeat each c)->b) { body(
diff --git a/validation-test/compiler_crashers_2/04b50eac547c7b87.swift b/validation-test/compiler_crashers_2/04b50eac547c7b87.swift
new file mode 100644
index 0000000000000..9b445c73794e8
--- /dev/null
+++ b/validation-test/compiler_crashers_2/04b50eac547c7b87.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"checkDistributedTargetResultType(swift::ValueDecl*, swift::Type, bool)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Distributed protocol a:DistributedActor{distributed actor:
diff --git a/validation-test/compiler_crashers_2/05e8f12d4126e38b.swift b/validation-test/compiler_crashers_2/05e8f12d4126e38b.swift
new file mode 100644
index 0000000000000..f08c6c8365e0b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/05e8f12d4126e38b.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::CallerSideDefaultArgExprRequest::OutputType swift::Evaluator::getResultUncached<swift::CallerSideDefaultArgExprRequest, swift::CallerSideDefaultArgExprRequest::OutputType swift::evaluateOrDefault<swift::CallerSideDefaultArgExprRequest>(swift::Evaluator&, swift::CallerSideDefaultArgExprRequest, swift::CallerSideDefaultArgExprRequest::OutputType)::'lambda'()>(swift::CallerSideDefaultArgExprRequest const&, swift::CallerSideDefaultArgExprRequest::OutputType swift::evaluateOrDefault<swift::CallerSideDefaultArgExprRequest>(swift::Evaluator&, swift::CallerSideDefaultArgExprRequest, swift::CallerSideDefaultArgExprRequest::OutputType)::'lambda'())"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a (Int -> Int , Int =
+#sourceLocation5
+ func b {
+  a {
+    $0
diff --git a/validation-test/compiler_crashers_2/0634c65af0140195.swift b/validation-test/compiler_crashers_2/0634c65af0140195.swift
new file mode 100644
index 0000000000000..bde8f87a15ce6
--- /dev/null
+++ b/validation-test/compiler_crashers_2/0634c65af0140195.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::PackType::getSingletonPackExpansion(swift::Type)","signatureAssert":"Assertion failed: (rootParameterPacks.size() >= 1), function getSingletonPackExpansion"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a func b < each c : a {
+  b
diff --git a/validation-test/compiler_crashers_2/076b298dbdff34f1.swift b/validation-test/compiler_crashers_2/076b298dbdff34f1.swift
new file mode 100644
index 0000000000000..8822d4fc8654c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/076b298dbdff34f1.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::TypeBase::getContextSubstitutions(swift::DeclContext const*, swift::GenericEnvironment*)","signatureAssert":"Assertion failed: (!baseTy->is<LValueType>() && !baseTy->is<AnyMetatypeType>() && !baseTy->is<ErrorType>()), function getContextSubstitutions"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a < b { wrappedValue : c var projectedValue init(projectedValue d) func e(@a & f g : b
diff --git a/validation-test/compiler_crashers_2/0771c5a9342d7660.swift b/validation-test/compiler_crashers_2/0771c5a9342d7660.swift
new file mode 100644
index 0000000000000..bbc745a206bc2
--- /dev/null
+++ b/validation-test/compiler_crashers_2/0771c5a9342d7660.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::getParameterAt(swift::ConcreteDeclRef, unsigned int)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a func b [{ lazy var c = a(d var e = b
diff --git a/validation-test/compiler_crashers_2/07e13fbf04cabfe9.swift b/validation-test/compiler_crashers_2/07e13fbf04cabfe9.swift
new file mode 100644
index 0000000000000..c6e7d79d71298
--- /dev/null
+++ b/validation-test/compiler_crashers_2/07e13fbf04cabfe9.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","original":"0052e8e2","signature":"swift::constraints::Solution::getFunctionArgApplyInfo(swift::constraints::ConstraintLocator*) const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+& &<##>
diff --git a/validation-test/compiler_crashers_2/087bf05037516d84.swift b/validation-test/compiler_crashers_2/087bf05037516d84.swift
new file mode 100644
index 0000000000000..22ab40268b63c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/087bf05037516d84.swift
@@ -0,0 +1,14 @@
+// {"kind":"typecheck","signature":"swift::rewriting::RewritePathEvaluator::applyRewriteRule(swift::rewriting::RewriteStep const&, swift::rewriting::RewriteSystem const&)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  associatedtype b : a where b.b == c
+}
+protocol d {
+  associatedtype e : a
+  associatedtype c : d
+  struct f<e : a> : d {
+    typealias c = f<e.b>
+    protocol g : d where c == f<e> {
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/0be4d5e8e2a66526.swift b/validation-test/compiler_crashers_2/0be4d5e8e2a66526.swift
new file mode 100644
index 0000000000000..d29eec1974282
--- /dev/null
+++ b/validation-test/compiler_crashers_2/0be4d5e8e2a66526.swift
@@ -0,0 +1,11 @@
+// {"kind":"emit-silgen","signature":"swift::Mangle::ASTMangler::appendConstrainedExistential(swift::Type, swift::GenericSignature, swift::ValueDecl const*)","stackOverflow":true}
+// RUN: not --crash %target-swift-frontend -emit-silgen %s
+protocol a<b> {
+  associatedtype b
+}
+struct c: a {
+  typealias b = c
+}
+func d() -> a<some a> {
+  c()
+}
diff --git a/validation-test/compiler_crashers_2/0ca37c33bbdab835.swift b/validation-test/compiler_crashers_2/0ca37c33bbdab835.swift
new file mode 100644
index 0000000000000..cdfc2fdf468ed
--- /dev/null
+++ b/validation-test/compiler_crashers_2/0ca37c33bbdab835.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::NonEphemeralConversionFailure::emitSuggestionNotes() const","signatureAssert":"Assertion failed: (pointeeType && \"Expected a pointer!\"), function operator()"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a(@_nonEphemeral UnsafePointer<Int8>?? ) var b = "" a(b
diff --git a/validation-test/compiler_crashers_2/0dd217e2a416bc8a.swift b/validation-test/compiler_crashers_2/0dd217e2a416bc8a.swift
new file mode 100644
index 0000000000000..7bcf4d07561d2
--- /dev/null
+++ b/validation-test/compiler_crashers_2/0dd217e2a416bc8a.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::rewriting::RewriteContext::getProtocolComponentRec(swift::ProtocolDecl const*, llvm::SmallVectorImpl<swift::ProtocolDecl const*>&)","signatureAssert":"Assertion failed: (found != Dependencies.end()), function getProtocolComponentRec"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a : b protocol b : c protocol d : a class c < e : d
diff --git a/validation-test/compiler_crashers_2/0e9a3e1eacb8f98e.swift b/validation-test/compiler_crashers_2/0e9a3e1eacb8f98e.swift
new file mode 100644
index 0000000000000..bedc4ba04cb1f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/0e9a3e1eacb8f98e.swift
@@ -0,0 +1,9 @@
+// {"kind":"typecheck","original":"cbf69c52","signature":"swift::constraints::SolverTrail::~SolverTrail()","signatureAssert":"Assertion failed: (Changes.empty() && \"Trail corrupted\"), function ~SolverTrail"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a<b> {
+  init(wrappedValue: a)
+  var wrappedValue: b
+}
+struct c {
+  @a @a var d: Int = 2
+}
diff --git a/validation-test/compiler_crashers_2/109d1c5355f6eab4.swift b/validation-test/compiler_crashers_2/109d1c5355f6eab4.swift
new file mode 100644
index 0000000000000..f5a9dd46fbc82
--- /dev/null
+++ b/validation-test/compiler_crashers_2/109d1c5355f6eab4.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::RequirementSignatureRequest::evaluate(swift::Evaluator&, swift::ProtocolDecl*) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a : b where c == d<e> protocol f : g protocol g {
+  associatedtype 2 : a
+}
+struct d < e extension d
+    : f protocol h{associatedtype e associatedtype c : g} protocol b : h
diff --git a/validation-test/compiler_crashers_2/12d3616c49ade22f.swift b/validation-test/compiler_crashers_2/12d3616c49ade22f.swift
new file mode 100644
index 0000000000000..e8b072ff9f526
--- /dev/null
+++ b/validation-test/compiler_crashers_2/12d3616c49ade22f.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"2ce52aa0","signature":"swift::constraints::ConstraintSystem::recordOpenedType(swift::constraints::ConstraintLocator*, llvm::ArrayRef<std::__1::pair<swift::GenericTypeParamType*, swift::TypeVariableType*>>, swift::constraints::PreparedOverloadBuilder*)","signatureAssert":"Assertion failed: (inserted), function recordOpenedType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  switch
+  0 {
+  case .a( ... b
diff --git a/validation-test/compiler_crashers_2/13a11e92edec70b6.swift b/validation-test/compiler_crashers_2/13a11e92edec70b6.swift
new file mode 100644
index 0000000000000..40edec0ba0482
--- /dev/null
+++ b/validation-test/compiler_crashers_2/13a11e92edec70b6.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::Parser::parseStmtConditionElement(llvm::SmallVectorImpl<swift::StmtConditionElement>&, swift::Diag<>, swift::StmtKind, llvm::StringRef&)","signatureAssert":"Assertion failed: (CurDeclContext->isLocalContext() && \"conditional binding in non-local context?!\"), function parseStmtConditionElement"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a: b[ if let
diff --git a/validation-test/compiler_crashers_2/13d9ae996c92be12.swift b/validation-test/compiler_crashers_2/13d9ae996c92be12.swift
new file mode 100644
index 0000000000000..64b73e28973d7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/13d9ae996c92be12.swift
@@ -0,0 +1,9 @@
+// {"kind":"typecheck","original":"369523c9","signature":"swift::InFlightSubstitution::substType(swift::SubstitutableType*, unsigned int)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a {
+  typealias b<c, d> = a
+  extension b<Float, Int> {
+    extension b {
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/1491559f83458126.swift b/validation-test/compiler_crashers_2/1491559f83458126.swift
new file mode 100644
index 0000000000000..1e890239f82a9
--- /dev/null
+++ b/validation-test/compiler_crashers_2/1491559f83458126.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintGraphNode::addConstraint(swift::constraints::Constraint*)","signatureAssert":"Assertion failed: (ConstraintIndex.count(constraint) == 0 && \"Constraint re-insertion\"), function addConstraint"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+[{
+    a
+    b
+  }
+c.d<b>
diff --git a/validation-test/compiler_crashers_2/15659ed9344b0eff.swift b/validation-test/compiler_crashers_2/15659ed9344b0eff.swift
new file mode 100644
index 0000000000000..519b2d4218930
--- /dev/null
+++ b/validation-test/compiler_crashers_2/15659ed9344b0eff.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"getTypeForSymbolRange(swift::rewriting::Symbol const*, swift::rewriting::Symbol const*, llvm::ArrayRef<swift::GenericTypeParamType*>, swift::rewriting::PropertyMap const&)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Combine extension Publishers.Share{a <b , c where Upstream == Publishers.FlatMap <b, c>{func a <c where Upstream == Publishers.FlatMap <b, c>, c.Output ==
diff --git a/validation-test/compiler_crashers_2/16194a387970a2e6.swift b/validation-test/compiler_crashers_2/16194a387970a2e6.swift
new file mode 100644
index 0000000000000..8f9de5a731080
--- /dev/null
+++ b/validation-test/compiler_crashers_2/16194a387970a2e6.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ResolvePattern::visitTupleExpr(swift::TupleExpr*)","signatureAssert":"Assertion failed: (!elts[0].getLabel().empty()), function create"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+switch { case (repeat a
diff --git a/validation-test/compiler_crashers_2/1801de8a256df48e.swift b/validation-test/compiler_crashers_2/1801de8a256df48e.swift
new file mode 100644
index 0000000000000..ecf8220b91853
--- /dev/null
+++ b/validation-test/compiler_crashers_2/1801de8a256df48e.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::rewriting::RequirementMachine::verify(swift::rewriting::MutableTerm const&) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  typealias Index extension Collection where Self : a{b : Index} protocol a
diff --git a/validation-test/compiler_crashers_2/1b160ff20a2ad5be.swift b/validation-test/compiler_crashers_2/1b160ff20a2ad5be.swift
new file mode 100644
index 0000000000000..0412716ea6229
--- /dev/null
+++ b/validation-test/compiler_crashers_2/1b160ff20a2ad5be.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::Parser::parseAbstractFunctionBody(swift::AbstractFunctionDecl*, swift::optionset::OptionSet<swift::Parser::ParseDeclFlags, unsigned short>)","signatureAssert":"Assertion failed: (!Flags.contains(PD_StubOnly) && \"stub-only should parse body immediately\"), function parseAbstractFunctionBody"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@abi(func a {
diff --git a/validation-test/compiler_crashers_2/1be7dd4882cd8c39.swift b/validation-test/compiler_crashers_2/1be7dd4882cd8c39.swift
new file mode 100644
index 0000000000000..c8a6625e2c5ca
--- /dev/null
+++ b/validation-test/compiler_crashers_2/1be7dd4882cd8c39.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::NormalProtocolConformance::getAssociatedConformance(swift::Type, swift::ProtocolDecl*) const","signatureAssert":"Assertion failed: (!AssociatedConformances[index]), function setAssociatedConformance"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a{typealias b : IteratorProtocol} extension a{typealias Element =
+                                                           b.Element} protocol c
+    : a{typealias b typealias Element} protocol d
+    : c{typealias Element} protocol e : d struct f : e
diff --git a/validation-test/compiler_crashers_2/1e0e4ce6cf612c7b.swift b/validation-test/compiler_crashers_2/1e0e4ce6cf612c7b.swift
new file mode 100644
index 0000000000000..c12ce414ca305
--- /dev/null
+++ b/validation-test/compiler_crashers_2/1e0e4ce6cf612c7b.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"checkRequirementsImpl(llvm::ArrayRef<swift::Requirement>, bool)","signatureAssert":"Assertion failed: (!firstType->hasTypeVariable()), function checkRequirementsImpl"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<b: ~Copyable
+  extension a: Copyable where b: Copyable
+    let c  (a -> d
diff --git a/validation-test/compiler_crashers_2/21fbeea5d06bd505.swift b/validation-test/compiler_crashers_2/21fbeea5d06bd505.swift
new file mode 100644
index 0000000000000..6b097c1b456f0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/21fbeea5d06bd505.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"createEnumSwitch(swift::ASTContext&, swift::DeclContext*, swift::Expr*, swift::EnumDecl*, swift::EnumDecl*, bool, std::__1::function<std::__1::tuple<swift::EnumElementDecl*, swift::BraceStmt*> (swift::EnumElementDecl*, swift::EnumElementDecl*, llvm::ArrayRef<swift::VarDecl*>)>)","signatureAssert":"Assertion failed: (paramDecl->hasDefaultExpr()), function operator()"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum a : Codable { case x( x : Int b : Double enum XCodingKeys : CodingKey{
+x case x case b let c = a
diff --git a/validation-test/compiler_crashers_2/2215911b0aba3c39.swift b/validation-test/compiler_crashers_2/2215911b0aba3c39.swift
new file mode 100644
index 0000000000000..781b401358c69
--- /dev/null
+++ b/validation-test/compiler_crashers_2/2215911b0aba3c39.swift
@@ -0,0 +1,15 @@
+// {"kind":"emit-silgen","original":"e8914023","signature":"swift::Lowering::AbstractionPattern::getNumFunctionParams() const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -emit-silgen %s
+func a<b, each c>(
+  _: (repeat each c)!,
+  _: b
+) {
+}
+struct d {
+  let e = ""
+  static func == (g: Self, f: Self) {
+    let h =
+      \.e as (Self) -> _
+    a(h, f)
+  }
+}
diff --git a/validation-test/compiler_crashers_2/23dbe8bd740c095a.swift b/validation-test/compiler_crashers_2/23dbe8bd740c095a.swift
new file mode 100644
index 0000000000000..71fd346745f36
--- /dev/null
+++ b/validation-test/compiler_crashers_2/23dbe8bd740c095a.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::TypeChecker::checkDeclAttributes(swift::Decl*)","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a { b }
+@_implements(a, b) typealias c =
diff --git a/validation-test/compiler_crashers_2/254cc6af0002dea1.swift b/validation-test/compiler_crashers_2/254cc6af0002dea1.swift
new file mode 100644
index 0000000000000..83f782bb598d0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/254cc6af0002dea1.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"ce7c1d7b","signature":"matchCallArguments(swift::constraints::ConstraintSystem&, swift::FunctionType*, swift::ArgumentList*, llvm::ArrayRef<swift::AnyFunctionType::Param>, llvm::ArrayRef<swift::AnyFunctionType::Param>, swift::constraints::ConstraintKind, swift::constraints::ConstraintLocatorBuilder, std::__1::optional<swift::constraints::TrailingClosureMatching>, llvm::SmallVectorImpl<std::__1::pair<swift::TypeVariableType*, swift::ExistentialArchetypeType*>>&)","signatureAssert":"Assertion failed: (param), function matchCallArguments"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<each b>(c: (repeat each b) -> Void) {
+  c($c: d)
+}
diff --git a/validation-test/compiler_crashers_2/259af6e17cc94d25.swift b/validation-test/compiler_crashers_2/259af6e17cc94d25.swift
new file mode 100644
index 0000000000000..f71c9f8825a1a
--- /dev/null
+++ b/validation-test/compiler_crashers_2/259af6e17cc94d25.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"void llvm::function_ref<void (swift::constraints::Constraint*, swift::ValueDecl*, swift::FunctionType*)>::callback_fn<(anonymous namespace)::findFavoredChoicesBasedOnArity(swift::constraints::ConstraintSystem&, swift::constraints::Constraint*, swift::ArgumentList*, llvm::function_ref<void (swift::constraints::Constraint*)>)::$_0>(long, swift::constraints::Constraint*, swift::ValueDecl*, swift::FunctionType*)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+var a: Any
+let a : () -> Void = a (b)
diff --git a/validation-test/compiler_crashers_2/267b1378f37f8563.swift b/validation-test/compiler_crashers_2/267b1378f37f8563.swift
new file mode 100644
index 0000000000000..0c9652905e5e5
--- /dev/null
+++ b/validation-test/compiler_crashers_2/267b1378f37f8563.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::applySolutionFixes(swift::constraints::Solution const&)","aliases":["swift::constraints::AllowArgumentMismatch::create(swift::constraints::ConstraintSystem&, swift::Type, swift::Type, swift::constraints::ConstraintLocator*)"]}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol b {
+  c<each d >(repeat each d, e: (
+}
+func bar(a: b) {
+  a.c(e : ""
diff --git a/validation-test/compiler_crashers_2/275b15e1edc79b4f.swift b/validation-test/compiler_crashers_2/275b15e1edc79b4f.swift
new file mode 100644
index 0000000000000..5b110af4e9f3e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/275b15e1edc79b4f.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::TypeSubstituter::transformDependentMemberType(swift::DependentMemberType*, swift::TypePosition)","stackOverflow":true}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a: Collection where Iterator == Self
+  struct b<c: a>: IteratorProtocol {next -> c.Element? struct c: a {
+      struct Element
+        subscript(Int) Element
+        func makeIterator -> b<Self>
diff --git a/validation-test/compiler_crashers_2/294a06f55bd8bcd7.swift b/validation-test/compiler_crashers_2/294a06f55bd8bcd7.swift
new file mode 100644
index 0000000000000..63f43fddd8efd
--- /dev/null
+++ b/validation-test/compiler_crashers_2/294a06f55bd8bcd7.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::GenericSignatureImpl::getReducedTypeParameter(swift::CanType) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum b : c protocol
+a{typealias c : d.e struct d : a func c typealias e} typealias c : a
diff --git a/validation-test/compiler_crashers_2/298b1482f76558b1.swift b/validation-test/compiler_crashers_2/298b1482f76558b1.swift
new file mode 100644
index 0000000000000..807742e285dfc
--- /dev/null
+++ b/validation-test/compiler_crashers_2/298b1482f76558b1.swift
@@ -0,0 +1,9 @@
+// {"kind":"typecheck","original":"06d6e891","signature":"(anonymous namespace)::ExprRewriter::coerceToType(swift::Expr*, swift::Type, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (toType && !toType->hasError() && !toType->hasTypeVariableOrPlaceholder()), function coerceToType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<b {
+  @propertyWrapper struct f<b {
+    wrappedValue : b    var projectedValue: a<b>  init(projectedValue:
+  }
+    c(@f arg: Int)
+  func d(e: a<Int>) {
+    c($arg: e
diff --git a/validation-test/compiler_crashers_2/298c18942254d677.swift b/validation-test/compiler_crashers_2/298c18942254d677.swift
new file mode 100644
index 0000000000000..2d75e7a11b75b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/298c18942254d677.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"454af16a","signature":"swift::Mangle::ASTMangler::appendClosureComponents(swift::CanType, unsigned int, bool, swift::DeclContext const*, llvm::ArrayRef<swift::GenericEnvironment*>)","stackOverflow":true}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol P {
+}
+{
+  return a
+  func a() -> some P
+}
diff --git a/validation-test/compiler_crashers_2/2a435f4c7a59cd72.swift b/validation-test/compiler_crashers_2/2a435f4c7a59cd72.swift
new file mode 100644
index 0000000000000..dabec35c339f8
--- /dev/null
+++ b/validation-test/compiler_crashers_2/2a435f4c7a59cd72.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","original":"b3234b81","signature":"swift::constraints::ConstraintSystem::recordImpliedResult(swift::Expr*, swift::constraints::ImpliedResultKind)","signatureAssert":"Assertion failed: (inserted && \"Duplicate implied result?\"), function recordImpliedResult"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+[
+  switch 0 {
+  case .a(
+    if <#expression#> {
+      b
+    }):
+  }
+]
diff --git a/validation-test/compiler_crashers_2/2b51707d0f37036f.swift b/validation-test/compiler_crashers_2/2b51707d0f37036f.swift
new file mode 100644
index 0000000000000..6608ea55d2a48
--- /dev/null
+++ b/validation-test/compiler_crashers_2/2b51707d0f37036f.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::recordMatchCallArgumentResult(swift::constraints::ConstraintLocator*, swift::constraints::MatchCallArgumentResult)","signatureAssert":"Assertion failed: (inserted), function recordMatchCallArgumentResult"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+if
+case.a(a.b) = {
diff --git a/validation-test/compiler_crashers_2/2c275be8b6c03f6b.swift b/validation-test/compiler_crashers_2/2c275be8b6c03f6b.swift
new file mode 100644
index 0000000000000..2f4a90d1e112a
--- /dev/null
+++ b/validation-test/compiler_crashers_2/2c275be8b6c03f6b.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"isParamListRepresentableInLanguage(swift::AbstractFunctionDecl const*, swift::ParameterList const*, swift::ObjCReason)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+class a { @objc b(@e & d Int) @propertyWrapper enum e
diff --git a/validation-test/compiler_crashers_2/2c8d3a95fcb84248.swift b/validation-test/compiler_crashers_2/2c8d3a95fcb84248.swift
new file mode 100644
index 0000000000000..8b7da5a499807
--- /dev/null
+++ b/validation-test/compiler_crashers_2/2c8d3a95fcb84248.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::recordRequiredImportAccessLevelForDecl(swift::Decl const*, swift::DeclContext const*, swift::AccessLevel, std::__1::function<void (swift::AttributedImport<swift::ImportedModule>)>)"}
+// RUN: %empty-directory(%t)
+// RUN: not --crash %target-swift-frontend -typecheck -sdk %t %s
+// REQUIRES: OS=macosx
+import Distributed
+distributed actor a {
+}
diff --git a/validation-test/compiler_crashers_2/2e580d3af692e43c.swift b/validation-test/compiler_crashers_2/2e580d3af692e43c.swift
new file mode 100644
index 0000000000000..48e748d26120d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/2e580d3af692e43c.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::Parser::parseTypeSimple(swift::Diag<>, swift::Parser::ParseTypeReason)","signatureAssert":"Assertion failed: (getPtrOrNull() && \"not checked for nullptr\"), function get"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+subscript(a: ~b <
diff --git a/validation-test/compiler_crashers_2/2e9f8c21a3644ca9.swift b/validation-test/compiler_crashers_2/2e9f8c21a3644ca9.swift
new file mode 100644
index 0000000000000..cc7910ca8af02
--- /dev/null
+++ b/validation-test/compiler_crashers_2/2e9f8c21a3644ca9.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"3a7e17d4","signature":"swift::TypeBase::computeInvertibleConformances()","signatureAssert":"Assertion failed: (!canType->hasUnboundGenericType()), function computeInvertibleConformances"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<b
+  extension a
+...
diff --git a/validation-test/compiler_crashers_2/3056ff53cabf9480.swift b/validation-test/compiler_crashers_2/3056ff53cabf9480.swift
new file mode 100644
index 0000000000000..b739c826f8c76
--- /dev/null
+++ b/validation-test/compiler_crashers_2/3056ff53cabf9480.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::setClosureType(swift::ClosureExpr const*, swift::FunctionType*)","signatureAssert":"Assertion failed: (inserted), function setClosureType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol b let c = {(a : b)in switch a{case.d {
diff --git a/validation-test/compiler_crashers_2/3070c3e372b52e7e.swift b/validation-test/compiler_crashers_2/3070c3e372b52e7e.swift
new file mode 100644
index 0000000000000..e3c91df940ad0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/3070c3e372b52e7e.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::recordResolvedOverload(swift::constraints::ConstraintLocator*, swift::constraints::SelectedOverload)","signatureAssert":"Assertion failed: (inserted), function recordResolvedOverload"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a func b(c : a) {
+  {
+    switch
+      c { case .baz(c==
diff --git a/validation-test/compiler_crashers_2/3077f0fa215b2f94.swift b/validation-test/compiler_crashers_2/3077f0fa215b2f94.swift
new file mode 100644
index 0000000000000..ba1c28e9ba54e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/3077f0fa215b2f94.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::Type llvm::function_ref<swift::Type (swift::SubstitutableType*)>::callback_fn<swift::TypeResolution::applyUnboundGenericArguments(swift::GenericTypeDecl*, swift::Type, swift::SourceLoc, llvm::ArrayRef<swift::Type>) const::$_0 const>(long, swift::SubstitutableType*)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a extension a {
+  class b {
+    struct c < f struct d func e->c<d>
diff --git a/validation-test/compiler_crashers_2/32bd25d0f0f96b1e.swift b/validation-test/compiler_crashers_2/32bd25d0f0f96b1e.swift
new file mode 100644
index 0000000000000..c6b88359629f3
--- /dev/null
+++ b/validation-test/compiler_crashers_2/32bd25d0f0f96b1e.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::TypeTransform<swift::Type::transformRec(llvm::function_ref<std::__1::optional<swift::Type> (swift::TypeBase*)>) const::Transform>::doIt(swift::Type, swift::TypePosition)","signatureAssert":"Assertion failed: (flags.getValueOwnership() == ValueOwnership::Default), function doIt"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<b>((__shared b) -> Void)
+func c(UnsafeMutablePointer<UInt8>) a {
+  c(&$0
diff --git a/validation-test/compiler_crashers_2/35c1917cd0f5ba23.swift b/validation-test/compiler_crashers_2/35c1917cd0f5ba23.swift
new file mode 100644
index 0000000000000..3649786c52270
--- /dev/null
+++ b/validation-test/compiler_crashers_2/35c1917cd0f5ba23.swift
@@ -0,0 +1,7 @@
+// {"signature":"swift::ASTWalker::PostWalkResult<swift::DynamicTypeExpr*> (anonymous namespace)::Verifier::dispatchVisitPost<swift::DynamicTypeExpr*>(swift::DynamicTypeExpr*)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a {
+}
+[].filter {
+  type(of: $0) == a.self
+}
diff --git a/validation-test/compiler_crashers_2/361c5acf488944d1.swift b/validation-test/compiler_crashers_2/361c5acf488944d1.swift
new file mode 100644
index 0000000000000..992f05ec4722f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/361c5acf488944d1.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::InFlightSubstitution::substType(swift::SubstitutableType*, unsigned int)","signatureAssert":"Assertion failed: (!substEltType->is<PackExpansionType>() && \"substituted shape mismatch: expected a scalar component\"), function projectLaneFromPackType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+typealias a<b, c, d> = () struct e < each b {
+  typealias f<each c, d> = (repeat a<each b, each c, d>)struct g < each c {
+          typealias h< each d > = (repeat f< repeat each c, each d >
+  struct i typealias j< each d > =
+      e< i >.g< repeat each b >.h< repeat each d >
diff --git a/validation-test/compiler_crashers_2/36e4eac6ff343df0.swift b/validation-test/compiler_crashers_2/36e4eac6ff343df0.swift
new file mode 100644
index 0000000000000..43d11d74ee65f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/36e4eac6ff343df0.swift
@@ -0,0 +1,13 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::getClosureType(swift::ClosureExpr const*) const","signatureAssert":"Assertion failed: (result), function getClosureType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a<b {
+  wrappedValue: b
+}
+func c( Bool)d {
+  @a var e: Bool? =
+    if .random() {
+      return
+    } else {
+      true
+    }
+  c(e
diff --git a/validation-test/compiler_crashers_2/37982596fdde0b5d.swift b/validation-test/compiler_crashers_2/37982596fdde0b5d.swift
new file mode 100644
index 0000000000000..d0240baebef4e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/37982596fdde0b5d.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::FailureDiagnostic::resolveType(swift::Type, bool, bool) const","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum a { b } {
+let:
+  String->a = a.b
diff --git a/validation-test/compiler_crashers_2/3b24e8bed8732c5c.swift b/validation-test/compiler_crashers_2/3b24e8bed8732c5c.swift
new file mode 100644
index 0000000000000..959e35065bbc1
--- /dev/null
+++ b/validation-test/compiler_crashers_2/3b24e8bed8732c5c.swift
@@ -0,0 +1,12 @@
+// {"kind":"emit-ir","signature":"swift::irgen::FulfillmentMap::searchNominalTypeMetadata(swift::irgen::IRGenModule&, swift::CanType, swift::MetadataState, unsigned int, swift::irgen::MetadataPath&&, swift::irgen::FulfillmentMap::InterestingKeysCallback const&)","stackOverflow":true}
+// RUN: not --crash %target-swift-frontend -emit-ir %s
+class a<b> {
+}
+protocol c {
+  associatedtype f: a<d>
+  associatedtype d
+}
+extension c where Self == f, f == d {
+  func e() {
+  }
+}
diff --git a/validation-test/compiler_crashers_2/3b6836d8e254e362.swift b/validation-test/compiler_crashers_2/3b6836d8e254e362.swift
new file mode 100644
index 0000000000000..04cc1a620d72e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/3b6836d8e254e362.swift
@@ -0,0 +1,9 @@
+// {"signature":"(anonymous namespace)::Traversal::doIt(swift::Expr*)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  for b 0 ..< 10 {
+    let a = Array(0 ..< b)
+    for c d a{
+      for e d c... {
+        Array(a[c ..< e].reversed())
+        f
diff --git a/validation-test/compiler_crashers_2/3ba9659c560ebf6a.swift b/validation-test/compiler_crashers_2/3ba9659c560ebf6a.swift
new file mode 100644
index 0000000000000..9cb0d2c3dfeb1
--- /dev/null
+++ b/validation-test/compiler_crashers_2/3ba9659c560ebf6a.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::ast_scope::ASTScopeImpl::checkSourceRangeBeforeAddingChild(swift::ast_scope::ASTScopeImpl*, swift::ASTContext const&) const","signatureAssert":"Assertion failed: ((SM.isBefore(range.Start, range.End) || range.Start == range.End) && \"scope source range ends before start\"), function getCharSourceRangeOfScope"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  @in
diff --git a/validation-test/compiler_crashers_2/3e3dd6a23227714f.swift b/validation-test/compiler_crashers_2/3e3dd6a23227714f.swift
new file mode 100644
index 0000000000000..0018f8d87839b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/3e3dd6a23227714f.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"1e8c9260","signature":"(anonymous namespace)::ExprWalker::walkToExprPost(swift::Expr*)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a {
+callAsFunction {
+\a()
diff --git a/validation-test/compiler_crashers_2/3f12a40864c30e4b.swift b/validation-test/compiler_crashers_2/3f12a40864c30e4b.swift
new file mode 100644
index 0000000000000..67dd5012bf5dc
--- /dev/null
+++ b/validation-test/compiler_crashers_2/3f12a40864c30e4b.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","original":"a275ad03","signature":"swift::Parser::parseTypeInlineArray(swift::SourceLoc)","signatureAssert":"Assertion failed: (Tok.is(K) && \"Consuming wrong token kind\"), function consumeToken"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+[a & 3 of
diff --git a/validation-test/compiler_crashers_2/40188c379c9ebe45.swift b/validation-test/compiler_crashers_2/40188c379c9ebe45.swift
new file mode 100644
index 0000000000000..0b5d7cc2da4cc
--- /dev/null
+++ b/validation-test/compiler_crashers_2/40188c379c9ebe45.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"b8967a13","signature":"(anonymous namespace)::ActorIsolationChecker::checkLocalCaptures(swift::AnyFunctionRef)","signatureAssert":"Assertion failed: (Captures.hasBeenComputed()), function getCaptureInfo"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a() {
+  extension <#type#> {
+    var b = {
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/4059e8d9978c8be6.swift b/validation-test/compiler_crashers_2/4059e8d9978c8be6.swift
new file mode 100644
index 0000000000000..d8e02791c4d1a
--- /dev/null
+++ b/validation-test/compiler_crashers_2/4059e8d9978c8be6.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"4dcd6877","signature":"swift::Parser::parseStmtForEach(swift::LabeledStmtInfo)","signatureAssert":"Assertion failed: (InBindingPattern == PatternBindingState::NotInBinding && \"for-each loops cannot exist inside other patterns\"), function parseStmtForEach"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+guard
+  let if <#expression#> {
+    for <#pattern#> in <#expression#> {
+    }
+  } else {
+  }
diff --git a/validation-test/compiler_crashers_2/438c8a321d9be3de.swift b/validation-test/compiler_crashers_2/438c8a321d9be3de.swift
new file mode 100644
index 0000000000000..a92dbfa98b075
--- /dev/null
+++ b/validation-test/compiler_crashers_2/438c8a321d9be3de.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::SameTypeRequirementFailure::SameTypeRequirementFailure(swift::constraints::Solution const&, swift::Type, swift::Type, swift::constraints::ConstraintLocator*)","signatureAssert":"Assertion failed: (getGenericContext() && \"Affected decl not within a generic context?\"), function RequirementFailure"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a struct b extension Dictionary : a where Value == let func !c {
+  let d : [Int:b] let : a = d
diff --git a/validation-test/compiler_crashers_2/4414db6acd8120aa.swift b/validation-test/compiler_crashers_2/4414db6acd8120aa.swift
new file mode 100644
index 0000000000000..f07982e466715
--- /dev/null
+++ b/validation-test/compiler_crashers_2/4414db6acd8120aa.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::ast_scope::ASTScopeImpl::addChild(swift::ast_scope::ASTScopeImpl*, swift::ASTContext&)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a < >>
diff --git a/validation-test/compiler_crashers_2/442f5cd1363787db.swift b/validation-test/compiler_crashers_2/442f5cd1363787db.swift
new file mode 100644
index 0000000000000..1e1edf55391cd
--- /dev/null
+++ b/validation-test/compiler_crashers_2/442f5cd1363787db.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::Decl::getResolvedCustomAttrType(swift::CustomAttr*) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a {
+  @b c, () {
diff --git a/validation-test/compiler_crashers_2/4437c5c5a209553a.swift b/validation-test/compiler_crashers_2/4437c5c5a209553a.swift
new file mode 100644
index 0000000000000..22829fd297b3c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/4437c5c5a209553a.swift
@@ -0,0 +1,13 @@
+// {"kind":"typecheck","original":"5af4a4fb","signature":"swift::constraints::ConstraintSystem::getBindingsFor(swift::TypeVariableType*)","signatureAssert":"Assertion failed: (typeVar->getImpl().getRepresentative(nullptr) == typeVar && \"not a representative\"), function getBindingsFor"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a {
+  func b(arr: [a]) {
+    arr.compactMap {
+      { c in
+        d ?? {
+          $0..
+        }
+      }
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/4546ece627bfc746.swift b/validation-test/compiler_crashers_2/4546ece627bfc746.swift
new file mode 100644
index 0000000000000..c60b487b5896e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/4546ece627bfc746.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::addFix(swift::constraints::ConstraintFix*)","signatureAssert":"Assertion failed: (inserted), function addFix"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<b>(b) -> b a(["":0]) as [Int:String]
diff --git a/validation-test/compiler_crashers_2/457eda8b0f9011b6.swift b/validation-test/compiler_crashers_2/457eda8b0f9011b6.swift
new file mode 100644
index 0000000000000..19f0a1b4e8909
--- /dev/null
+++ b/validation-test/compiler_crashers_2/457eda8b0f9011b6.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::setCapturedExpansions(swift::AnyFunctionRef, llvm::SmallVector<swift::PackExpansionExpr*, 1u>)","signatureAssert":"Assertion failed: (CapturedExpansions.count(func) == 0 && \"Cannot reset captured expansions\"), function setCapturedExpansions"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  repeat a {
diff --git a/validation-test/compiler_crashers_2/45e1131d17a7561c.swift b/validation-test/compiler_crashers_2/45e1131d17a7561c.swift
new file mode 100644
index 0000000000000..c75874fd4e5eb
--- /dev/null
+++ b/validation-test/compiler_crashers_2/45e1131d17a7561c.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::diagnoseAmbiguity(llvm::ArrayRef<swift::constraints::Solution>)","signatureAssert":"Assertion failed: (false && \"locator could not be simplified to anchor\"), function diagnoseAmbiguity"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a { eq = "" b "Self ecuador1 Self) > Bool {
+    let getProperties = (
+      \.eq as Self -> _
+  let eq = ""
diff --git a/validation-test/compiler_crashers_2/45fab60ba6296372.swift b/validation-test/compiler_crashers_2/45fab60ba6296372.swift
new file mode 100644
index 0000000000000..ef7e8f5b02c57
--- /dev/null
+++ b/validation-test/compiler_crashers_2/45fab60ba6296372.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"d550fd71","signature":"diagSyntacticUseRestrictions(swift::Expr const*, swift::DeclContext const*, bool)::DiagnoseWalker::walkToExprPre(swift::Expr*)","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  @<#type#>
+  #a([
+    &(b = 0)
+  ])
+}
diff --git a/validation-test/compiler_crashers_2/462ee2aa7dc23cf3.swift b/validation-test/compiler_crashers_2/462ee2aa7dc23cf3.swift
new file mode 100644
index 0000000000000..8e2883b176372
--- /dev/null
+++ b/validation-test/compiler_crashers_2/462ee2aa7dc23cf3.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"recordTypeWitness(swift::NormalProtocolConformance*, swift::AssociatedTypeDecl*, swift::Type, swift::TypeDecl*)","signatureAssert":"Assertion failed: (conformance->getTypeWitnessUncached(assocType) .getWitnessType() ->isEqual(type) && \"Conflicting type witness deductions\"), function recordTypeWitness"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a{associatedtype b} protocol c
+    : a{d(b)} protocol e{associatedtype f} extension e {
+  protocol g : e, c { associatedtype f : c associatedtype b }
+  struct h<i> : g {
+    typealias f = i
diff --git a/validation-test/compiler_crashers_2/4809d4cf70584858.swift b/validation-test/compiler_crashers_2/4809d4cf70584858.swift
new file mode 100644
index 0000000000000..7a74858a42cf8
--- /dev/null
+++ b/validation-test/compiler_crashers_2/4809d4cf70584858.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::Parser::consumeTokenWithoutFeedingReceiver()","signatureAssert":"Assertion failed: (Tok.isNot(tok::eof) && \"Lexing past eof!\"), function discardToken"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@_extern(a
diff --git a/validation-test/compiler_crashers_2/486a70c43d10bda5.swift b/validation-test/compiler_crashers_2/486a70c43d10bda5.swift
new file mode 100644
index 0000000000000..f5c619d49e980
--- /dev/null
+++ b/validation-test/compiler_crashers_2/486a70c43d10bda5.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ConnectedComponents::unionSets(swift::TypeVariableType*, swift::TypeVariableType*)","signatureAssert":"Assertion failed: (validComponentCount > 0), function unionSets"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+let b = ( c , d a {
+e b
diff --git a/validation-test/compiler_crashers_2/488f1cb3053826d0.swift b/validation-test/compiler_crashers_2/488f1cb3053826d0.swift
new file mode 100644
index 0000000000000..6069e8d81ace9
--- /dev/null
+++ b/validation-test/compiler_crashers_2/488f1cb3053826d0.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::TypeChecker::typeCheckCheckedCast(swift::Type, swift::Type, swift::CheckedCastContextKind, swift::DeclContext*)","signatureAssert":"Assertion failed: (!toType->isAny() && \"casts to 'Any' should've been handled above\"), function typeCheckCheckedCast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+init(a : () -> ()) {
+  [.init ?? a]
+}
diff --git a/validation-test/compiler_crashers_2/497c0938db36de8f.swift b/validation-test/compiler_crashers_2/497c0938db36de8f.swift
new file mode 100644
index 0000000000000..4a68c4fa7e92b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/497c0938db36de8f.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","signature":"swift::IsObjCRequest::evaluate(swift::Evaluator&, swift::ValueDecl*) const","signatureAssert":"Assertion failed: (errorConvention && \"Missing error convention\"), function markAsObjC"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+class a {
+  @objc var b : Int {
+    get throws {
+    }
+    set
+  }
+}
diff --git a/validation-test/compiler_crashers_2/49ab67ad3514bb58.swift b/validation-test/compiler_crashers_2/49ab67ad3514bb58.swift
new file mode 100644
index 0000000000000..da5c4d8b46d34
--- /dev/null
+++ b/validation-test/compiler_crashers_2/49ab67ad3514bb58.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"cloneRawLiteralExpr(swift::ASTContext&, swift::LiteralExpr*)","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+a enum a : Double { case = 3.7 case
diff --git a/validation-test/compiler_crashers_2/4ae85881765dc0db.swift b/validation-test/compiler_crashers_2/4ae85881765dc0db.swift
new file mode 100644
index 0000000000000..0e6dfbc59db8e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/4ae85881765dc0db.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"diagnoseAmbiguityWithContextualType(swift::constraints::ConstraintSystem&, swift::constraints::SolutionDiff&, llvm::ArrayRef<std::__1::pair<swift::constraints::Solution const*, swift::constraints::ConstraintFix const*>>, llvm::ArrayRef<swift::constraints::Solution>)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a func b< c >(c = a(
+    func a
diff --git a/validation-test/compiler_crashers_2/4c48b3ae4546ae0d.swift b/validation-test/compiler_crashers_2/4c48b3ae4546ae0d.swift
new file mode 100644
index 0000000000000..15aed1f6e3a05
--- /dev/null
+++ b/validation-test/compiler_crashers_2/4c48b3ae4546ae0d.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::recordKeyPath(swift::KeyPathExpr const*, swift::TypeVariableType*, swift::TypeVariableType*, swift::DeclContext*)","signatureAssert":"Assertion failed: (inserted), function recordKeyPath"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum a { b->a{switch self{case.c(\ d) e
diff --git a/validation-test/compiler_crashers_2/4fbd0bc38c141e94.swift b/validation-test/compiler_crashers_2/4fbd0bc38c141e94.swift
new file mode 100644
index 0000000000000..eb5d90521f6cd
--- /dev/null
+++ b/validation-test/compiler_crashers_2/4fbd0bc38c141e94.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::TypeChecker::typeCheckParameterDefault(swift::Expr*&, swift::DeclContext*, swift::Type, bool, bool)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+init<a>(b: a == {
diff --git a/validation-test/compiler_crashers_2/50b52589da464db0.swift b/validation-test/compiler_crashers_2/50b52589da464db0.swift
new file mode 100644
index 0000000000000..5b4bb7834f1e7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/50b52589da464db0.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::ExprPatternMatchRequest::evaluate(swift::Evaluator&, swift::ExprPattern const*) const","signatureAssert":"Assertion failed: (EP->isResolved() && \"Must only be queried once resolved\"), function evaluate"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum a { b(c : a){{guard case.b = c
diff --git a/validation-test/compiler_crashers_2/50b7d05928ee8b0e.swift b/validation-test/compiler_crashers_2/50b7d05928ee8b0e.swift
new file mode 100644
index 0000000000000..5c0b3fe59fc2f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/50b7d05928ee8b0e.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"7f0c85e8","signature":"diagSyntacticUseRestrictions(swift::Expr const*, swift::DeclContext const*, bool)::DiagnoseWalker::walkToExprPre(swift::Expr*)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a<b, c>: ExpressibleByDictionaryLiteral {
+  typealias Key = b
+  typealias Value = c
+  func d<b, c>(a    <b, c>) {
+    {
+      d(["": 2
diff --git a/validation-test/compiler_crashers_2/51e2471a4cadad3d.swift b/validation-test/compiler_crashers_2/51e2471a4cadad3d.swift
new file mode 100644
index 0000000000000..623d96e96f1f6
--- /dev/null
+++ b/validation-test/compiler_crashers_2/51e2471a4cadad3d.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::repairFailures(swift::Type, swift::Type, swift::constraints::ConstraintKind, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, llvm::SmallVectorImpl<swift::constraints::RestrictionOrFix>&, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Foundation func a(b: AnyClass?) { b (b
diff --git a/validation-test/compiler_crashers_2/52afb182b33879f5.swift b/validation-test/compiler_crashers_2/52afb182b33879f5.swift
new file mode 100644
index 0000000000000..e153e70d1c4f4
--- /dev/null
+++ b/validation-test/compiler_crashers_2/52afb182b33879f5.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::TypeBase::getSuperclassForDecl(swift::ClassDecl const*, bool)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a {
+  typealias b = c class e : a protocol d : e, d.b
diff --git a/validation-test/compiler_crashers_2/5367d3b1ce20b9aa.swift b/validation-test/compiler_crashers_2/5367d3b1ce20b9aa.swift
new file mode 100644
index 0000000000000..6d0105b8caf0d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5367d3b1ce20b9aa.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::NominalTypeDecl::lookupConformance(swift::ProtocolDecl*, llvm::SmallVectorImpl<swift::ProtocolConformance*>&) const","signatureAssert":"Assertion failed: (!isa<ProtocolDecl>(this) && \"Self-conformances are only found by the higher-level \" \"swift::lookupConformance() entry point\"), function lookupConformance"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+@objc protocol a{a} extension a {
+  a class b : a
diff --git a/validation-test/compiler_crashers_2/545a00bc1537bba5.swift b/validation-test/compiler_crashers_2/545a00bc1537bba5.swift
new file mode 100644
index 0000000000000..721c4d01dedb3
--- /dev/null
+++ b/validation-test/compiler_crashers_2/545a00bc1537bba5.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"54198387","signature":"swift::Expr* llvm::function_ref<swift::Expr* (swift::Expr*)>::callback_fn<fixMissingArguments(swift::constraints::ConstraintSystem&, swift::ASTNode, llvm::SmallVectorImpl<swift::AnyFunctionType::Param>&, llvm::ArrayRef<swift::AnyFunctionType::Param>, unsigned int, swift::constraints::ConstraintLocatorBuilder)::$_0>(long, swift::Expr*)","signatureAssert":"Assertion failed: (!baseName.isSpecial() && \"Can't retrieve the identifier of a special base name\"), function getBaseIdentifier"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<b>(
+  c: (b, ()) -> b = {
+    $0.init
+  })
diff --git a/validation-test/compiler_crashers_2/5592e8470c61624d.swift b/validation-test/compiler_crashers_2/5592e8470c61624d.swift
new file mode 100644
index 0000000000000..8deb7cd241e17
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5592e8470c61624d.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::GenericEnvironment::getMappingIfPresent(swift::CanType) const","signatureAssert":"Assertion failed: (Index < Length && \"Invalid index!\"), function operator[]"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  struct b < each c {
+    extension a {
+      struct d {
+        e(repeat(each c))
diff --git a/validation-test/compiler_crashers_2/56561b790b963b0c.swift b/validation-test/compiler_crashers_2/56561b790b963b0c.swift
new file mode 100644
index 0000000000000..ad0dbe5d9f39b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/56561b790b963b0c.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","original":"0f52c8c0","signature":"swift::constraints::ConstraintSystem::simplifyExplicitGenericArgumentsConstraint(swift::Type, swift::Type, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (found != openedOverloadTypes.end()), function simplifyExplicitGenericArgumentsConstraint"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a {
+  struct b
+    struct b< a {
+      struct c<d {
+        e = b< f>.c< >
diff --git a/validation-test/compiler_crashers_2/56777ed1a15575c4.swift b/validation-test/compiler_crashers_2/56777ed1a15575c4.swift
new file mode 100644
index 0000000000000..d89753504936f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/56777ed1a15575c4.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"bb182de2","signature":"swift::constraints::ConstraintSystem::simplifyKeyPathConstraint(swift::Type, swift::Type, swift::Type, llvm::ArrayRef<swift::TypeVariableType*>, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (contextualRootTy && contextualValueTy), function operator()"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a < each b > {
+  var
+    c : (repeat each b) {
+      (repeat \ .)
+  }
+}
diff --git a/validation-test/compiler_crashers_2/570ee53be7e5846a.swift b/validation-test/compiler_crashers_2/570ee53be7e5846a.swift
new file mode 100644
index 0000000000000..5459ba74edd01
--- /dev/null
+++ b/validation-test/compiler_crashers_2/570ee53be7e5846a.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::GenericSignatureImpl::getReducedTypeParameter(swift::CanType) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  protocol a{associatedtype b} extension a {
+    extension a {
+      struct c {
+        d : b
diff --git a/validation-test/compiler_crashers_2/579b1d0c15fcb172.swift b/validation-test/compiler_crashers_2/579b1d0c15fcb172.swift
new file mode 100644
index 0000000000000..0d95904ef3210
--- /dev/null
+++ b/validation-test/compiler_crashers_2/579b1d0c15fcb172.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::diagnoseArgumentLabelError(swift::ASTContext&, swift::ArgumentList const*, llvm::ArrayRef<swift::Identifier>, swift::ParameterContext, swift::InFlightDiagnostic*)","signatureAssert":"Assertion failed: ((numMissing + numExtra + numWrong > 0) && \"Should not call this function with nothing to diagnose\"), function diagnoseArgumentLabelError"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<b>((), c : ()->b) a {}
+c : {
diff --git a/validation-test/compiler_crashers_2/579f310114c8e906.swift b/validation-test/compiler_crashers_2/579f310114c8e906.swift
new file mode 100644
index 0000000000000..ee2233d115473
--- /dev/null
+++ b/validation-test/compiler_crashers_2/579f310114c8e906.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::GenericTypeParamDecl::getSourceRange() const","signatureAssert":"Assertion failed: (Start.isValid() == End.isValid() && \"Start and end should either both be valid or both be invalid!\"), function SourceRange"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a { associatedtype b }
+public
+struct c < d : a extension c {
+public
+  typealias e = d.b
diff --git a/validation-test/compiler_crashers_2/57c38714066765f0.swift b/validation-test/compiler_crashers_2/57c38714066765f0.swift
new file mode 100644
index 0000000000000..78c9c193bdff4
--- /dev/null
+++ b/validation-test/compiler_crashers_2/57c38714066765f0.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintGraph::computeConnectedComponents(llvm::ArrayRef<swift::TypeVariableType*>)","signatureAssert":"Assertion failed: (component != components.end()), function operator()"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+let i = Array(... a { " ? \(i Array* )" }
+                        , b 1
diff --git a/validation-test/compiler_crashers_2/5939b8697d0d25c0.swift b/validation-test/compiler_crashers_2/5939b8697d0d25c0.swift
new file mode 100644
index 0000000000000..cb6468e4fb33d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5939b8697d0d25c0.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"diagSyntacticUseRestrictions(swift::Expr const*, swift::DeclContext const*, bool)::DiagnoseWalker::walkToExprPre(swift::Expr*)","signatureAssert":"Assertion failed: (noncopyableTy->is<TupleType>() && \"will use poor wording\"), function walkToExprPre"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{ @#b([a:
diff --git a/validation-test/compiler_crashers_2/5ac7591881325acd.swift b/validation-test/compiler_crashers_2/5ac7591881325acd.swift
new file mode 100644
index 0000000000000..be9ada1f24b45
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5ac7591881325acd.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::Constraint::Constraint(swift::constraints::ConstraintKind, swift::Type, swift::Type, swift::constraints::ConstraintLocator*, llvm::SmallPtrSetImpl<swift::TypeVariableType*>&)","signatureAssert":"Assertion failed: (isAdmissibleType(First)), function Constraint"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+extension _UIntBuffer {
+  a {
+    struct b : OptionSet
diff --git a/validation-test/compiler_crashers_2/5b22e73536516908.swift b/validation-test/compiler_crashers_2/5b22e73536516908.swift
new file mode 100644
index 0000000000000..94a6caf1c03a0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5b22e73536516908.swift
@@ -0,0 +1,9 @@
+// {"kind":"typecheck","original":"6f23f24c","signature":"diagnoseUnintendedOptionalBehavior(swift::Expr const*, swift::DeclContext const*)::UnintendedOptionalBehaviorWalker::walkToExprPre(swift::Expr*)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  @<#type#>
+  #a {
+    &b
+    0 as c
+  }
+}
diff --git a/validation-test/compiler_crashers_2/5b828cc4df77dc2e.swift b/validation-test/compiler_crashers_2/5b828cc4df77dc2e.swift
new file mode 100644
index 0000000000000..c40d4c7cdb7a6
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5b828cc4df77dc2e.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::diagnoseAmbiguityWithFixes(llvm::SmallVectorImpl<swift::constraints::Solution>&)","signatureAssert":"Assertion failed: (fn), function diagnoseAmbiguity"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a {
+  lazy b : Int -> Int = {
+    b(0.0
+    1
+  }
+  b : Int -> Int
diff --git a/validation-test/compiler_crashers_2/5cbe6a68da313ea9.swift b/validation-test/compiler_crashers_2/5cbe6a68da313ea9.swift
new file mode 100644
index 0000000000000..1a4b5a675b5e7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5cbe6a68da313ea9.swift
@@ -0,0 +1,6 @@
+// {"signature":"swift::AvailabilityScope::verify(swift::AvailabilityScope const*, swift::ASTContext&) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+if
+#available({}
+  else {
+    var a
diff --git a/validation-test/compiler_crashers_2/5ccf43ee108a37e9.swift b/validation-test/compiler_crashers_2/5ccf43ee108a37e9.swift
new file mode 100644
index 0000000000000..966a8c18b54e3
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5ccf43ee108a37e9.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::LifetimeDependenceChecker::diagnoseMissingResultDependencies(swift::DiagID)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@abi(func a->b) func a < b
diff --git a/validation-test/compiler_crashers_2/5e95d57077abad38.swift b/validation-test/compiler_crashers_2/5e95d57077abad38.swift
new file mode 100644
index 0000000000000..bc8e1c46fd474
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5e95d57077abad38.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::rewriting::RewriteContext::getRelativeTermForType(swift::CanType, llvm::ArrayRef<swift::rewriting::Term>)","signatureAssert":"Assertion failed: (result.back().getKind() != Symbol::Kind::Shape), function getRelativeTermForType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+extension Result {
+  func a<each b>() where Success == (Result) -> (repeat each b)> {}
+}
diff --git a/validation-test/compiler_crashers_2/5ed6119e7b5941e8.swift b/validation-test/compiler_crashers_2/5ed6119e7b5941e8.swift
new file mode 100644
index 0000000000000..7391ad4086bf7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5ed6119e7b5941e8.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::SpecifyLabelToAssociateTrailingClosure::diagnose(swift::constraints::Solution const&, bool) const","signatureAssert":"Assertion failed: (Index < Length && \"Invalid index!\"), function operator[]"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+a {}
+func a<each b, c>(repeat each b, c)
diff --git a/validation-test/compiler_crashers_2/5f942981131dbcab.swift b/validation-test/compiler_crashers_2/5f942981131dbcab.swift
new file mode 100644
index 0000000000000..4fcb677604574
--- /dev/null
+++ b/validation-test/compiler_crashers_2/5f942981131dbcab.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"matchCallArguments(swift::constraints::ConstraintSystem&, swift::FunctionType*, swift::ArgumentList*, llvm::ArrayRef<swift::AnyFunctionType::Param>, llvm::ArrayRef<swift::AnyFunctionType::Param>, swift::constraints::ConstraintKind, swift::constraints::ConstraintLocatorBuilder, std::__1::optional<swift::constraints::TrailingClosureMatching>, llvm::SmallVectorImpl<std::__1::pair<swift::TypeVariableType*, swift::ExistentialArchetypeType*>>&)","signatureAssert":"Assertion failed: (Index < Length && \"Invalid index!\"), function operator[]"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a< b, c >(b, d : KeyPath< b, c >b ) a ((e, at: f\g
diff --git a/validation-test/compiler_crashers_2/61ba98c06e51fee9.swift b/validation-test/compiler_crashers_2/61ba98c06e51fee9.swift
new file mode 100644
index 0000000000000..757f40096ed10
--- /dev/null
+++ b/validation-test/compiler_crashers_2/61ba98c06e51fee9.swift
@@ -0,0 +1,5 @@
+// {"kind":"emit-silgen","original":"e6da36c1","signature":"(anonymous namespace)::Transform::transform(swift::Lowering::ManagedValue, swift::Lowering::AbstractionPattern, swift::CanType, swift::Lowering::AbstractionPattern, swift::CanType, swift::SILType, swift::Lowering::SGFContext)"}
+// RUN: not --crash %target-swift-frontend -emit-silgen %s
+// REQUIRES: OS=macosx
+import Foundation
+[["": ""]] as [[String: AnyObject]?]
diff --git a/validation-test/compiler_crashers_2/622ea03bc2be3e4f.swift b/validation-test/compiler_crashers_2/622ea03bc2be3e4f.swift
new file mode 100644
index 0000000000000..9186b3f8b9f2a
--- /dev/null
+++ b/validation-test/compiler_crashers_2/622ea03bc2be3e4f.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","signature":"swift::TypeBase::getContextSubstitutions(swift::DeclContext const*, swift::GenericEnvironment*)","signatureAssert":"Assertion failed: (0 && \"Bad base type\"), function getContextSubstitutions"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a< b {
+  @propertyWrapper struct e {
+    var wrappedValue
+        projectedValue : a
+                                        init(projectedValue
+                                             a) {
+      func d(@e b) d($e
+                                                            : f
diff --git a/validation-test/compiler_crashers_2/6235b4422a78fa73.swift b/validation-test/compiler_crashers_2/6235b4422a78fa73.swift
new file mode 100644
index 0000000000000..c5c3fd25f2db1
--- /dev/null
+++ b/validation-test/compiler_crashers_2/6235b4422a78fa73.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::rewriting::RewriteContext::getRelativeTermForType(swift::CanType, llvm::ArrayRef<swift::rewriting::Term>)","signatureAssert":"Assertion failed: (result.back().getKind() != Symbol::Kind::Shape), function getRelativeTermForType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// https://github.com/swiftlang/swift/issues/84490
+struct a < b > {
+  func
+    c < each d where (repeat each d , b) == b>()
+}
diff --git a/validation-test/compiler_crashers_2/63d065624970638a.swift b/validation-test/compiler_crashers_2/63d065624970638a.swift
new file mode 100644
index 0000000000000..45877c4560305
--- /dev/null
+++ b/validation-test/compiler_crashers_2/63d065624970638a.swift
@@ -0,0 +1,8 @@
+// {"signature":"swift::GenericSignatureImpl::lookupNestedType(swift::Type, swift::Identifier) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+a.b
+protocol c where a.d == Self
+  protocol a {
+    associatedtype e : c
+    typealias b
+    typealias d = Self.f
diff --git a/validation-test/compiler_crashers_2/651fea1b598eb09d.swift b/validation-test/compiler_crashers_2/651fea1b598eb09d.swift
new file mode 100644
index 0000000000000..a101ce36288fc
--- /dev/null
+++ b/validation-test/compiler_crashers_2/651fea1b598eb09d.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConjunctionStep::~ConjunctionStep()","signatureAssert":"Assertion failed: (!bool(ActiveChoice)), function ~ConjunctionStep"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Foundation{let a = malloc(b.c <d>
diff --git a/validation-test/compiler_crashers_2/67f3134fa56c0913.swift b/validation-test/compiler_crashers_2/67f3134fa56c0913.swift
new file mode 100644
index 0000000000000..548884be65098
--- /dev/null
+++ b/validation-test/compiler_crashers_2/67f3134fa56c0913.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::ContextualFailure::diagnoseConversionToBool() const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a {
+  wrappedValue : Bool {
+    @a var b : Int
diff --git a/validation-test/compiler_crashers_2/685973a04a9055ad.swift b/validation-test/compiler_crashers_2/685973a04a9055ad.swift
new file mode 100644
index 0000000000000..1748e97d40745
--- /dev/null
+++ b/validation-test/compiler_crashers_2/685973a04a9055ad.swift
@@ -0,0 +1,9 @@
+// {"signature":"(anonymous namespace)::ExprRewriter::coerceToType(swift::Expr*, swift::Type, swift::constraints::ConstraintLocatorBuilder)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a < each b : Collection {
+      c : ( repeat each b
+        extension
+  struct Index {
+          d : (repeat(each b.Index
+  } var endIndex : Index {
+                      Index(d: repeat (each c).endIndex
diff --git a/validation-test/compiler_crashers_2/698f276cef6d3418.swift b/validation-test/compiler_crashers_2/698f276cef6d3418.swift
new file mode 100644
index 0000000000000..a849109089a8b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/698f276cef6d3418.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::DefaultAndMaxAccessLevelRequest::cacheResult(std::__1::pair<swift::AccessLevel, swift::AccessLevel>) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a < b extension a where b : c, d == a {
+  protocol c struct a
diff --git a/validation-test/compiler_crashers_2/6993045a54031680.swift b/validation-test/compiler_crashers_2/6993045a54031680.swift
new file mode 100644
index 0000000000000..2a327f0443766
--- /dev/null
+++ b/validation-test/compiler_crashers_2/6993045a54031680.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","original":"96fa6e3e","signature":"swift::StorageImplInfoRequest::evaluate(swift::Evaluator&, swift::AbstractStorageDecl*) const","signatureAssert":"Assertion failed: (info.hasStorage() == storage->hasStorage() || storage->getASTContext().Diags.hadAnyError()), function evaluate"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a {
+  func b() {
+    override var c: Any {
+      didSet {
+      }
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/6a334017072c7458.swift b/validation-test/compiler_crashers_2/6a334017072c7458.swift
new file mode 100644
index 0000000000000..50b050d7ae73c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/6a334017072c7458.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","signature":"swift::constraints::FunctionTypeMismatch::FunctionTypeMismatch(swift::constraints::Solution const&, swift::ContextualTypePurpose, swift::Type, swift::Type, llvm::ArrayRef<unsigned int>, swift::constraints::ConstraintLocator*)","signatureAssert":"Assertion failed: (getFromType()->is<AnyFunctionType>() && getToType()->is<AnyFunctionType>()), function FunctionTypeMismatch"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a < b, c {
+  typealias d = b typealias e =
+      c class f<b, c> : a<b, c> class g<h, i> : f<(h, i), c> {
+    j = d->e class g<h> : f<(h, i), c> {
+      k {
+        j = d->e
diff --git a/validation-test/compiler_crashers_2/6b3f4ab0a969ffc0.swift b/validation-test/compiler_crashers_2/6b3f4ab0a969ffc0.swift
new file mode 100644
index 0000000000000..07fd4242dfcd9
--- /dev/null
+++ b/validation-test/compiler_crashers_2/6b3f4ab0a969ffc0.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","original":"8e10a6ec","signature":"(anonymous namespace)::Verifier::verifyChecked(swift::IdentityExpr*)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<b> {
+}
+func c<each d>(e: repeat a<each d>) {
+  (try repeat each e)
+}
diff --git a/validation-test/compiler_crashers_2/6b4f7c705d8aa6ba.swift b/validation-test/compiler_crashers_2/6b4f7c705d8aa6ba.swift
new file mode 100644
index 0000000000000..78e9600e21ac4
--- /dev/null
+++ b/validation-test/compiler_crashers_2/6b4f7c705d8aa6ba.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"2e6c789c","signature":"swift::MacroDecl::getIntroducedNames(swift::MacroRole, swift::ValueDecl*, llvm::SmallVectorImpl<swift::DeclName>&) const","signatureAssert":"Assertion failed: (!isSpecial() && \"Cannot retrieve identifier from special names\"), function getIdentifier"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+a
+@TaskLocal init()
diff --git a/validation-test/compiler_crashers_2/6cbf07908427d45f.swift b/validation-test/compiler_crashers_2/6cbf07908427d45f.swift
new file mode 100644
index 0000000000000..2f219dd0663d6
--- /dev/null
+++ b/validation-test/compiler_crashers_2/6cbf07908427d45f.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::Decl::getLoc(bool) const","signatureAssert":"Assertion failed: (Val && \"isa<> used on a null pointer\"), function doit"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@_typeEraser(a) protocol b dynamic func c->some b {
+  d
diff --git a/validation-test/compiler_crashers_2/6e4c01d8fc888909.swift b/validation-test/compiler_crashers_2/6e4c01d8fc888909.swift
new file mode 100644
index 0000000000000..6b031944cb24d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/6e4c01d8fc888909.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","original":"58cef9f3","signature":"swift::Parser::parseTypeInlineArray(swift::SourceLoc)","signatureAssert":"Assertion failed: (getPtrOrNull() && \"not checked for nullptr\"), function get"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+[[3] of
diff --git a/validation-test/compiler_crashers_2/70bfb18ab58de217.swift b/validation-test/compiler_crashers_2/70bfb18ab58de217.swift
new file mode 100644
index 0000000000000..301be3e472bb8
--- /dev/null
+++ b/validation-test/compiler_crashers_2/70bfb18ab58de217.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::GenericContext::getGenericSignature() const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a < let b : c
+  class c < b : a
diff --git a/validation-test/compiler_crashers_2/70de1cb82aa09307.swift b/validation-test/compiler_crashers_2/70de1cb82aa09307.swift
new file mode 100644
index 0000000000000..30d7c195a5b80
--- /dev/null
+++ b/validation-test/compiler_crashers_2/70de1cb82aa09307.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"0ca20e45","signature":"(anonymous namespace)::SyntacticElementSolutionApplication::apply()","signatureAssert":"Assertion failed: (!empty()), function back"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{ a -> Void! in
+} {
+}
diff --git a/validation-test/compiler_crashers_2/730082a7a3112508.swift b/validation-test/compiler_crashers_2/730082a7a3112508.swift
new file mode 100644
index 0000000000000..2da705fcd4734
--- /dev/null
+++ b/validation-test/compiler_crashers_2/730082a7a3112508.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::AssignmentFailure::diagnoseAsError()","signatureAssert":"Assertion failed: (!baseName.isSpecial() && \"Can't retrieve the identifier of a special base name\"), function getBaseIdentifier"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a let _ a.init = 0
diff --git a/validation-test/compiler_crashers_2/7315b4568a81e97d.swift b/validation-test/compiler_crashers_2/7315b4568a81e97d.swift
new file mode 100644
index 0000000000000..7c614858de512
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7315b4568a81e97d.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::GenericSignature::verify(llvm::ArrayRef<swift::Requirement>) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  typealias b where Self : a protocol a
diff --git a/validation-test/compiler_crashers_2/7375195b753c3ca3.swift b/validation-test/compiler_crashers_2/7375195b753c3ca3.swift
new file mode 100644
index 0000000000000..f09613973d7f5
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7375195b753c3ca3.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"fixRequirementFailure(swift::constraints::ConstraintSystem&, swift::Type, swift::Type, swift::ASTNode, llvm::ArrayRef<swift::constraints::ConstraintLocator::PathElement>)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a func b< each c : a >(repeat each c) b( d repeat {
diff --git a/validation-test/compiler_crashers_2/7459efb59886f47d.swift b/validation-test/compiler_crashers_2/7459efb59886f47d.swift
new file mode 100644
index 0000000000000..30951ccb2e92f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7459efb59886f47d.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::DerivedConformance::deriveDistributedActor(swift::ValueDecl*)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Distributed typealias DefaultDistributedActorSystem = LocalTestingDistributedActorSystem distributed actor a{c, b
diff --git a/validation-test/compiler_crashers_2/7498c8f669ed545b.swift b/validation-test/compiler_crashers_2/7498c8f669ed545b.swift
new file mode 100644
index 0000000000000..d06560a11d7c2
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7498c8f669ed545b.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"18b55723","signature":"swift::constraints::Solution::getFunctionArgApplyInfo(swift::constraints::ConstraintLocator*) const","signatureAssert":"Assertion failed: (Val && \"isa<> used on a null pointer\"), function doit"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Foundation
+func a( CGFloat,  CGFloat?)
+a((1.0: (
diff --git a/validation-test/compiler_crashers_2/750bcc84cc8b7789.swift b/validation-test/compiler_crashers_2/750bcc84cc8b7789.swift
new file mode 100644
index 0000000000000..f42947e9b5095
--- /dev/null
+++ b/validation-test/compiler_crashers_2/750bcc84cc8b7789.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"7e87f396","signature":"swift::Mangle::ASTMangler::appendOpaqueTypeArchetype(swift::ArchetypeType*, swift::OpaqueTypeDecl*, swift::SubstitutionMap, swift::GenericSignature, swift::ValueDecl const*)","signatureAssert":"Assertion failed: (subs.isIdentity()), function appendOpaqueTypeArchetype"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a
+  func b<c> -> some a where c
+=
diff --git a/validation-test/compiler_crashers_2/7565b5c58a59aef8.swift b/validation-test/compiler_crashers_2/7565b5c58a59aef8.swift
new file mode 100644
index 0000000000000..f87339c40dd32
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7565b5c58a59aef8.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"a290b075","signature":"(anonymous namespace)::ASTScopeDeclConsumerForLocalLookup::consume(llvm::ArrayRef<swift::ValueDecl*>, swift::NullablePtr<swift::DeclContext>)","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  @abi(func & ) var a  (b
diff --git a/validation-test/compiler_crashers_2/7569a0726f21e49f.swift b/validation-test/compiler_crashers_2/7569a0726f21e49f.swift
new file mode 100644
index 0000000000000..77d241fe24a61
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7569a0726f21e49f.swift
@@ -0,0 +1,10 @@
+// {"kind":"emit-silgen","original":"f261a4a8","signature":"(anonymous namespace)::ResultPlanner::planIntoDirect(swift::Lowering::AbstractionPattern, swift::CanType, swift::Lowering::AbstractionPattern, swift::CanType, swift::SILResultInfo)","signatureAssert":"Assertion failed: (!outerOrigType.isTuple() || !SGF.silConv.useLoweredAddresses()), function planIntoDirect"}
+// RUN: not --crash %target-swift-frontend -emit-silgen %s
+infix operator <*> : AdditionPrecedence
+func <*> <a, b>(c: ((a) -> b?)?, d: a) -> b? {
+}
+func cons<e, h>(c: e) -> (h) -> (e, h) {
+}
+var g = ""
+if let f = cons <*> g <*> () {
+}
diff --git a/validation-test/compiler_crashers_2/756ba8587e7eb26b.swift b/validation-test/compiler_crashers_2/756ba8587e7eb26b.swift
new file mode 100644
index 0000000000000..400b75db3b19b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/756ba8587e7eb26b.swift
@@ -0,0 +1,6 @@
+// {"signature":"(anonymous namespace)::Verifier::verifyChecked(swift::Type)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a < b {
+  d {
+    class e<c, b> : a struct f subscript<g>(h : e<f, g>) {
+      h.d base
diff --git a/validation-test/compiler_crashers_2/7600ddcfabb24e63.swift b/validation-test/compiler_crashers_2/7600ddcfabb24e63.swift
new file mode 100644
index 0000000000000..83e4acab25801
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7600ddcfabb24e63.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"115aa383","signature":"swift::TypeChecker::lookupUnqualified(swift::DeclContext*, swift::DeclNameRef, swift::SourceLoc, swift::optionset::OptionSet<swift::NameLookupFlags, unsigned int>)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  struct b<c {
+    d    extension Never {
+      struct e {
+b {
+  d
diff --git a/validation-test/compiler_crashers_2/760438013f44ce5b.swift b/validation-test/compiler_crashers_2/760438013f44ce5b.swift
new file mode 100644
index 0000000000000..fe5763adf9c8f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/760438013f44ce5b.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::DeclContext::getSelfInterfaceType() const","signatureAssert":"Assertion failed: (isTypeContext()), function getSelfInterfaceType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+distributed func a
diff --git a/validation-test/compiler_crashers_2/788743a67e00ba80.swift b/validation-test/compiler_crashers_2/788743a67e00ba80.swift
new file mode 100644
index 0000000000000..88e022323163d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/788743a67e00ba80.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::bindOverloadType(swift::constraints::SelectedOverload const&, swift::Type, swift::constraints::ConstraintLocator*, swift::DeclContext*)","signatureAssert":"Assertion failed: (constraints.size() == 1), function bindOverloadType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@dynamicMemberLookup struct a<b > {
+  subscript <c>(dynamicMember d: WritableKeyPath<b, c>) -> a
+  let binding = {
+    buffer ?? binding
+  } [<#expression#>]
+}
diff --git a/validation-test/compiler_crashers_2/78fae776bebcee10.swift b/validation-test/compiler_crashers_2/78fae776bebcee10.swift
new file mode 100644
index 0000000000000..aacbe6e11421c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/78fae776bebcee10.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::QualifiedLookupRequest::evaluate(swift::Evaluator&, swift::DeclContext const*, llvm::SmallVector<swift::NominalTypeDecl*, 4u>, swift::DeclNameRef, swift::NLOptions) const","signatureAssert":"Assertion failed: (Val && \"isa<> used on a null pointer\"), function doit"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  extension a {
+  b {
+    func c<d>(e : d) {
+      e = f
diff --git a/validation-test/compiler_crashers_2/79ac90c35c46dbab.swift b/validation-test/compiler_crashers_2/79ac90c35c46dbab.swift
new file mode 100644
index 0000000000000..6c9312b6ea284
--- /dev/null
+++ b/validation-test/compiler_crashers_2/79ac90c35c46dbab.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::TypeJoin::join(swift::CanType, swift::CanType)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a protocol b < c { associatedtype c }
+                                 [ b<a>, a & b
diff --git a/validation-test/compiler_crashers_2/7c107da0279a073c.swift b/validation-test/compiler_crashers_2/7c107da0279a073c.swift
new file mode 100644
index 0000000000000..adffec2d09067
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7c107da0279a073c.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::PackType::getExpandedGenericArgs(llvm::ArrayRef<swift::GenericTypeParamType*>, llvm::ArrayRef<swift::Type>)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a < each b typealias c<each d> = a<> c < e
diff --git a/validation-test/compiler_crashers_2/7c81010b54046136.swift b/validation-test/compiler_crashers_2/7c81010b54046136.swift
new file mode 100644
index 0000000000000..690b9f58c90f2
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7c81010b54046136.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::matchTypes(swift::Type, swift::Type, swift::constraints::ConstraintKind, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, swift::constraints::ConstraintLocatorBuilder)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+weak var a : b? a
+class c
+  class b
+    weak var a: c?
diff --git a/validation-test/compiler_crashers_2/7d21b6234014b45d.swift b/validation-test/compiler_crashers_2/7d21b6234014b45d.swift
new file mode 100644
index 0000000000000..4239b4631f90c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7d21b6234014b45d.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::TypeResolution::applyUnboundGenericArguments(swift::GenericTypeDecl*, swift::Type, swift::SourceLoc, llvm::ArrayRef<swift::Type>) const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum a < let b : a<Int>> {
+}
diff --git a/validation-test/compiler_crashers_2/7e19cb4cc0598c1b.swift b/validation-test/compiler_crashers_2/7e19cb4cc0598c1b.swift
new file mode 100644
index 0000000000000..ee280cfebcbc1
--- /dev/null
+++ b/validation-test/compiler_crashers_2/7e19cb4cc0598c1b.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::MissingOptionalUnwrapFailure::offerForceUnwrapFixIt(swift::Expr const*) const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<let b: Int?{ int: Int { b
diff --git a/validation-test/compiler_crashers_2/807f13dbbc4a604f.swift b/validation-test/compiler_crashers_2/807f13dbbc4a604f.swift
new file mode 100644
index 0000000000000..85264ebbc1744
--- /dev/null
+++ b/validation-test/compiler_crashers_2/807f13dbbc4a604f.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::AccessLevelRequest::cacheResult(swift::AccessLevel) const","signatureAssert":"Assertion failed: (!hasAccess() && \"access already set\"), function setAccess"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a < b extension a where c == d {
+  protocol d
diff --git a/validation-test/compiler_crashers_2/845e7060267d8763.swift b/validation-test/compiler_crashers_2/845e7060267d8763.swift
new file mode 100644
index 0000000000000..7869ff251a9de
--- /dev/null
+++ b/validation-test/compiler_crashers_2/845e7060267d8763.swift
@@ -0,0 +1,3 @@
+// {"kind":"emit-silgen","original":"7b4a72a9","signature":"swift::getSILValueOwnership(llvm::ArrayRef<swift::SILValue>, swift::SILType)","signatureAssert":"Assertion failed: (v->getType().isObject()), function operator()"}
+// RUN: not --crash %target-swift-frontend -emit-silgen %s
+var a: Any = ["": [a]] as [String: [AnyObject?]]
diff --git a/validation-test/compiler_crashers_2/84cb3a91833322c6.swift b/validation-test/compiler_crashers_2/84cb3a91833322c6.swift
new file mode 100644
index 0000000000000..8823977b16601
--- /dev/null
+++ b/validation-test/compiler_crashers_2/84cb3a91833322c6.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::OutOfOrderArgumentFailure::diagnoseAsError()","signatureAssert":"Assertion failed: (idx < size()), function operator[]"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a(b : Int c : Int) a ((c: 1 b: 2
diff --git a/validation-test/compiler_crashers_2/84d2d3eac90e09a0.swift b/validation-test/compiler_crashers_2/84d2d3eac90e09a0.swift
new file mode 100644
index 0000000000000..f7e0c66a49ab7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/84d2d3eac90e09a0.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::getLoc(swift::ASTNode)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a {
+  wrappedValue : b var projectedValue init(projectedValue c) {
+    func d(@a Int) d
diff --git a/validation-test/compiler_crashers_2/863c70cdebd3a8f9.swift b/validation-test/compiler_crashers_2/863c70cdebd3a8f9.swift
new file mode 100644
index 0000000000000..2638b16f6478b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/863c70cdebd3a8f9.swift
@@ -0,0 +1,9 @@
+// {"kind":"typecheck","signature":"swift::Decl::getSemanticAvailableAttr(swift::AvailableAttr const*) const","signatureAssert":"Assertion failed: (declCtxt->isTypeContext()), function lookupReplacedDecl"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  @available(*, renamed : "process0") func a () {
+    async {
+      a
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/877192df03b9c32d.swift b/validation-test/compiler_crashers_2/877192df03b9c32d.swift
new file mode 100644
index 0000000000000..443d23805f41e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/877192df03b9c32d.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::TypeBase::computeInvertibleConformances()","signatureAssert":"Assertion failed: (!canType->hasUnboundGenericType()), function computeInvertibleConformances"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+typealias a = FlattenCollection...
diff --git a/validation-test/compiler_crashers_2/8867bfc8cf158ddb.swift b/validation-test/compiler_crashers_2/8867bfc8cf158ddb.swift
new file mode 100644
index 0000000000000..4916596578a2b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/8867bfc8cf158ddb.swift
@@ -0,0 +1,8 @@
+// {"signature":"swift::ClassDecl::isSuperclassOf(swift::ClassDecl const*) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a {
+  typealias b = <#type#>
+}
+class c< d > : a< > {
+}
+c.b
diff --git a/validation-test/compiler_crashers_2/8b32e8ab4ca6b321.swift b/validation-test/compiler_crashers_2/8b32e8ab4ca6b321.swift
new file mode 100644
index 0000000000000..16c0ddda59058
--- /dev/null
+++ b/validation-test/compiler_crashers_2/8b32e8ab4ca6b321.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::AnyFunctionType* swift::TypeBase::castTo<swift::AnyFunctionType>()","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+subscript(a: Int?) -> <#type#> {
+  var b = a
+  Float(b)
+}
diff --git a/validation-test/compiler_crashers_2/8bd36ffa67067b41.swift b/validation-test/compiler_crashers_2/8bd36ffa67067b41.swift
new file mode 100644
index 0000000000000..6b9b5b756ade6
--- /dev/null
+++ b/validation-test/compiler_crashers_2/8bd36ffa67067b41.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"07ee747b","signature":"swift::Type llvm::function_ref<swift::Type (swift::SubstitutableType*)>::callback_fn<swift::GenericEnvironment::mapElementTypeIntoPackContext(swift::Type) const::$_0>(long, swift::SubstitutableType*)","signatureAssert":"Assertion failed: (!elementEnv || elementEnv == archetype->getGenericEnvironment()), function operator()"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<each b>(c: (repeat each b) -> Void) -> (repeat each b) {
+  { before, each in
+    c(repeat before
+    repeat each
diff --git a/validation-test/compiler_crashers_2/8d0890396bc3d7c9.swift b/validation-test/compiler_crashers_2/8d0890396bc3d7c9.swift
new file mode 100644
index 0000000000000..17c032b246417
--- /dev/null
+++ b/validation-test/compiler_crashers_2/8d0890396bc3d7c9.swift
@@ -0,0 +1,6 @@
+// {"kind":"emit-silgen","original":"be1cdd08","signature":"swift::SILVisitorBase<(anonymous namespace)::SILVerifier, void>::visitSILBasicBlock(swift::SILBasicBlock*)"}
+// RUN: not --crash %target-swift-frontend -emit-silgen %s
+// REQUIRES: OS=macosx
+import Foundation
+var a = 1
+[a] as [NSNumber? ]
diff --git a/validation-test/compiler_crashers_2/8d7e9f1c8d765adf.swift b/validation-test/compiler_crashers_2/8d7e9f1c8d765adf.swift
new file mode 100644
index 0000000000000..9aba8f3efd165
--- /dev/null
+++ b/validation-test/compiler_crashers_2/8d7e9f1c8d765adf.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"3ea3fc6a","signature":"swift::DeclRefTypeRepr::DeclRefTypeRepr(swift::TypeReprKind, swift::DeclNameRef, swift::DeclNameLoc, unsigned int, bool)","signatureAssert":"Assertion failed: (Name.isSimpleName() && !Name.isSpecial() && !Name.isOperator()), function DeclRefTypeRepr"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+switch {
+case a. init(
diff --git a/validation-test/compiler_crashers_2/9010fe24c9dc7272.swift b/validation-test/compiler_crashers_2/9010fe24c9dc7272.swift
new file mode 100644
index 0000000000000..4c9a200f40fd7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9010fe24c9dc7272.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"1c912312","signature":"(anonymous namespace)::ExprRewriter::coerceCallArguments(swift::ArgumentList*, swift::AnyFunctionType*, swift::ConcreteDeclRef, swift::ApplyExpr*, swift::constraints::ConstraintLocatorBuilder, llvm::ArrayRef<swift::AppliedPropertyWrapper>)","signatureAssert":"Assertion failed: (!param.isInOut()), function coerceCallArguments"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a(  inout UnsafeMutableRawPointer...)
+a(
diff --git a/validation-test/compiler_crashers_2/912b50e86d7f221c.swift b/validation-test/compiler_crashers_2/912b50e86d7f221c.swift
new file mode 100644
index 0000000000000..996dcb59447a9
--- /dev/null
+++ b/validation-test/compiler_crashers_2/912b50e86d7f221c.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::AllowTypeOrInstanceMemberFailure::diagnoseAsError()","signatureAssert":"Assertion failed: (TypeDC->isTypeContext() && \"Expected type decl context!\"), function diagnoseAsError"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a func b<c >(c = a [
+       extension a {
+subscript->Int
diff --git a/validation-test/compiler_crashers_2/922c2062e63d9bad.swift b/validation-test/compiler_crashers_2/922c2062e63d9bad.swift
new file mode 100644
index 0000000000000..fcfac1a4190ee
--- /dev/null
+++ b/validation-test/compiler_crashers_2/922c2062e63d9bad.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"65735e17","signature":"swift::Decl::getResolvedCustomAttrType(swift::CustomAttr*) const","signatureAssert":"Assertion failed: (!canType->hasUnboundGenericType()), function computeInvertibleConformances"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a<b
+  struct c {
+    @a    ...var d
diff --git a/validation-test/compiler_crashers_2/933fe28af784ae94.swift b/validation-test/compiler_crashers_2/933fe28af784ae94.swift
new file mode 100644
index 0000000000000..47f21afaa86a0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/933fe28af784ae94.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ASTScopeDeclConsumerForUnqualifiedLookup::consume(llvm::ArrayRef<swift::ValueDecl*>, swift::NullablePtr<swift::DeclContext>)","signatureAssert":"Assertion failed: (Val && \"isa<> used on a null pointer\"), function doit"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  @abi(func a) var b : c
diff --git a/validation-test/compiler_crashers_2/93553842ae732503.swift b/validation-test/compiler_crashers_2/93553842ae732503.swift
new file mode 100644
index 0000000000000..a01d3036324e0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/93553842ae732503.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"lookupReplacedDecl(swift::DeclNameRef, swift::DeclAttribute const*, swift::ValueDecl const*, llvm::SmallVectorImpl<swift::ValueDecl*>&)","signatureAssert":"Assertion failed: (declCtxt->isTypeContext()), function lookupReplacedDecl"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{ @_dynamicReplacement(for: ) func a
diff --git a/validation-test/compiler_crashers_2/93b241538559442a.swift b/validation-test/compiler_crashers_2/93b241538559442a.swift
new file mode 100644
index 0000000000000..d780a2f82f213
--- /dev/null
+++ b/validation-test/compiler_crashers_2/93b241538559442a.swift
@@ -0,0 +1,5 @@
+// {"signature":"swift::ASTWalker::PostWalkResult<swift::MakeTemporarilyEscapableExpr*> (anonymous namespace)::Verifier::dispatchVisitPost<swift::MakeTemporarilyEscapableExpr*>(swift::MakeTemporarilyEscapableExpr*)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a(b: () -> Void, c: (() -> Void?) -> Void) {
+   withoutActuallyEscaping(b, do : c)
+ }
diff --git a/validation-test/compiler_crashers_2/9470fb8cc388d9a9.swift b/validation-test/compiler_crashers_2/9470fb8cc388d9a9.swift
new file mode 100644
index 0000000000000..68fe2564d0856
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9470fb8cc388d9a9.swift
@@ -0,0 +1,11 @@
+// {"kind":"typecheck","original":"cf72a9cd","signature":"swift::constraints::ConstraintSystem::recordResolvedOverload(swift::constraints::ConstraintLocator*, swift::constraints::SelectedOverload)","signatureAssert":"Assertion failed: (inserted), function recordResolvedOverload"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a {
+  func b(c: a) {
+    {
+      switch c {
+      case .baz(c==):
+      }
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/9601e1ccf3c48ef8.swift b/validation-test/compiler_crashers_2/9601e1ccf3c48ef8.swift
new file mode 100644
index 0000000000000..010a2ff1401c4
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9601e1ccf3c48ef8.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::simplifyKeyPathConstraint(swift::Type, swift::Type, swift::Type, llvm::ArrayRef<swift::TypeVariableType*>, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (bgt->isKeyPath() || bgt->isWritableKeyPath() || bgt->isReferenceWritableKeyPath()), function operator()"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<each b>() -> (repeat Array<each b>) {
+  (repeat \ [<#type#>])
+}
diff --git a/validation-test/compiler_crashers_2/963e71d8d54aa379.swift b/validation-test/compiler_crashers_2/963e71d8d54aa379.swift
new file mode 100644
index 0000000000000..33bdbc097e376
--- /dev/null
+++ b/validation-test/compiler_crashers_2/963e71d8d54aa379.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"e51afbca","signature":"swift::constraints::ConstraintSystem::diagnoseAmbiguityWithFixes(llvm::SmallVectorImpl<swift::constraints::Solution>&)","signatureAssert":"Assertion failed: (!empty()), function front"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a throw withThrowingTaskGroup(of : a) {
+b in
diff --git a/validation-test/compiler_crashers_2/975116cdaa9f4107.swift b/validation-test/compiler_crashers_2/975116cdaa9f4107.swift
new file mode 100644
index 0000000000000..74fe2d21e6210
--- /dev/null
+++ b/validation-test/compiler_crashers_2/975116cdaa9f4107.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::ExprPattern::updateMatchExpr(swift::Expr*) const::FindMatchOperatorDeclRef::walkToExprPre(swift::Expr*)","signatureAssert":"Assertion failed: (fnTy->getParams().size() == 2), function walkToExprPre"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func ~= (a) if case ~= b
diff --git a/validation-test/compiler_crashers_2/981bb1e42a9312c0.swift b/validation-test/compiler_crashers_2/981bb1e42a9312c0.swift
new file mode 100644
index 0000000000000..4571c1f1bf5f0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/981bb1e42a9312c0.swift
@@ -0,0 +1,11 @@
+// {"kind":"typecheck","original":"0639ef40","signature":"swift::constraints::ConstraintSystem::openGenericParameters(swift::DeclContext*, swift::GenericSignature, llvm::SmallVectorImpl<std::__1::pair<swift::GenericTypeParamType*, swift::TypeVariableType*>>&, swift::constraints::ConstraintLocatorBuilder, swift::constraints::PreparedOverloadBuilder*)","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  struct b {
+      c<d
+    {
+      struct e<f
+        extension Never {
+          struct g {
+      body {
+        e
diff --git a/validation-test/compiler_crashers_2/98887170a0bfefc0.swift b/validation-test/compiler_crashers_2/98887170a0bfefc0.swift
new file mode 100644
index 0000000000000..128642e6aa9b6
--- /dev/null
+++ b/validation-test/compiler_crashers_2/98887170a0bfefc0.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"$s11swiftASTGen24evaluatePoundIfCondition10astContext13diagEnginePtr16sourceFileBuffer02ifF4Text14shouldEvaluateSiSo17BridgedASTContextV_SvSo0S9StringRefVAKSbtF","signatureAssert":"Assertion failed: (size() >= 1 && \"must have a top-level module\"), function Module"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: swift_swift_parser
+#if canImport(#available
diff --git a/validation-test/compiler_crashers_2/98b9c480b4ec75d7.swift b/validation-test/compiler_crashers_2/98b9c480b4ec75d7.swift
new file mode 100644
index 0000000000000..41087feedf886
--- /dev/null
+++ b/validation-test/compiler_crashers_2/98b9c480b4ec75d7.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","signature":"swift::constraints::Solution::getFixedType(swift::TypeVariableType*) const","signatureAssert":"Assertion failed: (knownBinding != typeBindings.end()), function getFixedType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a {
+  static
+b {
+  return c ?? {
+    return c
+  }
+}
+c
diff --git a/validation-test/compiler_crashers_2/98fb6d3cc49f5d1d.swift b/validation-test/compiler_crashers_2/98fb6d3cc49f5d1d.swift
new file mode 100644
index 0000000000000..dc7c7135c2f1f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/98fb6d3cc49f5d1d.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::AbstractStorageDecl::mutability(swift::DeclContext const*, std::__1::optional<swift::DeclRefExpr const*>) const","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a {
+  @a $b:
diff --git a/validation-test/compiler_crashers_2/9967f3fc56f84a1e.swift b/validation-test/compiler_crashers_2/9967f3fc56f84a1e.swift
new file mode 100644
index 0000000000000..e13b25abc2e1b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9967f3fc56f84a1e.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"formatDiagnosticArgument(llvm::StringRef, llvm::StringRef, llvm::ArrayRef<swift::DiagnosticArgument>, unsigned int, swift::DiagnosticFormatOptions, llvm::raw_ostream&)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a func b(@a Int) b($c:d
diff --git a/validation-test/compiler_crashers_2/9b5b2007a0e08434.swift b/validation-test/compiler_crashers_2/9b5b2007a0e08434.swift
new file mode 100644
index 0000000000000..3841fbf3fbca7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9b5b2007a0e08434.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","signature":"swift::rewriting::RewriteSystem::buildRewritePathForJoiningTerms(swift::rewriting::MutableTerm, swift::rewriting::MutableTerm, swift::rewriting::RewritePath*) const","signatureAssert":"Assertion failed: (lhsTerm == rhsTerm), function buildRewritePathForJoiningTerms"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a : b
+  protocol c {
+    associatedtype d
+    associatedtype e: f where e.g == Self
+  }
+  protocol f: a
+    protocol b {
+      associatedtype g: c where g.d == Self!
diff --git a/validation-test/compiler_crashers_2/9c465a4c5d33b28c.swift b/validation-test/compiler_crashers_2/9c465a4c5d33b28c.swift
new file mode 100644
index 0000000000000..dbfc873647632
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9c465a4c5d33b28c.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"getTypeForSymbolRange(swift::rewriting::Symbol const*, swift::rewriting::Symbol const*, llvm::ArrayRef<swift::GenericTypeParamType*>, swift::rewriting::PropertyMap const&)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<each b { extension a!
diff --git a/validation-test/compiler_crashers_2/9ebf7cbda04a5be8.swift b/validation-test/compiler_crashers_2/9ebf7cbda04a5be8.swift
new file mode 100644
index 0000000000000..c397b5c884d9d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9ebf7cbda04a5be8.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","original":"5b785ef0","signature":"swift::ASTWalker::PreWalkResult<swift::Expr*> (anonymous namespace)::Verifier::dispatchVisitPreExpr<swift::OpenExistentialExpr*>(swift::OpenExistentialExpr*)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+extension Dictionary {
+    a(b: Sequence)
+  {
+    {
+      for c  d      b {
+        var values =
+          [] ?? {
+            values.append(c
diff --git a/validation-test/compiler_crashers_2/9f30635127b9f25f.swift b/validation-test/compiler_crashers_2/9f30635127b9f25f.swift
new file mode 100644
index 0000000000000..ef78de99efe71
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9f30635127b9f25f.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::PreCheckTarget::walkToExprPre(swift::Expr*)","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  extension a {
+    b {
+      func c {
+        super
diff --git a/validation-test/compiler_crashers_2/9f75fc85a5c32bf2.swift b/validation-test/compiler_crashers_2/9f75fc85a5c32bf2.swift
new file mode 100644
index 0000000000000..ec50b42dd95fe
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9f75fc85a5c32bf2.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::setTargetFor(swift::constraints::SyntacticElementTargetKey, swift::constraints::SyntacticElementTarget)","signatureAssert":"Assertion failed: (inserted), function setTargetFor"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{$0=[{} }(
+[a:
diff --git a/validation-test/compiler_crashers_2/9fbd87f3ba61177c.swift b/validation-test/compiler_crashers_2/9fbd87f3ba61177c.swift
new file mode 100644
index 0000000000000..545359ac0ca65
--- /dev/null
+++ b/validation-test/compiler_crashers_2/9fbd87f3ba61177c.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"45b18ebd","signature":"swift::rewriting::Symbol::Storage::Storage(swift::rewriting::Symbol::Kind, swift::CanType, llvm::ArrayRef<swift::rewriting::Term>)","signatureAssert":"Assertion failed: (!type->hasUnboundGenericType()), function Storage"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<b, c
+  enum d {
+    typealias e = a
+    extension a where b == d, c == b.e
diff --git a/validation-test/compiler_crashers_2/a014efdc02cfb729.swift b/validation-test/compiler_crashers_2/a014efdc02cfb729.swift
new file mode 100644
index 0000000000000..15af4de2d747d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a014efdc02cfb729.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::getDistributedActorSystemSerializationType(swift::NominalTypeDecl*)","signatureAssert":"Assertion failed: (!system->isDistributedActor()), function getDistributedActorSystemSerializationType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Distributed typealias a = LocalTestingDistributedActorSystem protocol a{distributed actor b:a
diff --git a/validation-test/compiler_crashers_2/a04f67aa8fb22efa.swift b/validation-test/compiler_crashers_2/a04f67aa8fb22efa.swift
new file mode 100644
index 0000000000000..e4855e6b00788
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a04f67aa8fb22efa.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"checkRequirementsImpl(llvm::ArrayRef<swift::Requirement>, bool)","signatureAssert":"Assertion failed: ((allowTypeParameters || !firstType->hasTypeParameter()) && \"must take a contextual type. if you really are ok with an \" \"indefinite answer (and usually YOU ARE NOT), then consider whether \" \"you really, definitely are ok with an indefinite answer, and \" \"use `checkRequirementsWithoutContext` instead\"), function checkRequirementsImpl"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a < Element {
+  b {
+    class c : Collection { typealias Index = d subscript(e :
diff --git a/validation-test/compiler_crashers_2/a0b4d94ad0e977d0.swift b/validation-test/compiler_crashers_2/a0b4d94ad0e977d0.swift
new file mode 100644
index 0000000000000..75f076613bc48
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a0b4d94ad0e977d0.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::findSyntacticErrorForConsume(swift::ModuleDecl*, swift::SourceLoc, swift::Expr*, llvm::function_ref<swift::Type (swift::Expr*)>)","signatureAssert":"Assertion failed: (!isa<ConsumeExpr>(subExpr) && \"operates on the sub-expr of a consume\"), function findSyntacticErrorForConsume"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a(consume : String) {
+  consume consume consume
diff --git a/validation-test/compiler_crashers_2/a12deef4ea310815.swift b/validation-test/compiler_crashers_2/a12deef4ea310815.swift
new file mode 100644
index 0000000000000..a52c7741e10d5
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a12deef4ea310815.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::DeclContext::getASTContext() const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@a({ struct b }
+                        var c
diff --git a/validation-test/compiler_crashers_2/a1776e4598146d49.swift b/validation-test/compiler_crashers_2/a1776e4598146d49.swift
new file mode 100644
index 0000000000000..3a487746a36f1
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a1776e4598146d49.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::PatternTypeRequest::evaluate(swift::Evaluator&, swift::ContextualPattern) const","signatureAssert":"Assertion failed: (!dyn_cast_or_null<SpecifierTypeRepr>(Repr) && \"Didn't resolve invalid type to error type!\"), function validateTypedPattern"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum a { b : _const a
diff --git a/validation-test/compiler_crashers_2/a23d151072660954.swift b/validation-test/compiler_crashers_2/a23d151072660954.swift
new file mode 100644
index 0000000000000..db00ff4df0480
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a23d151072660954.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"checkRequirementsImpl(llvm::ArrayRef<swift::Requirement>, bool)","signatureAssert":"Assertion failed: (!firstType->hasTypeVariable()), function checkRequirementsImpl"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<b: ~Copyable
+  extension a: Copyable where b: Copyable
+    let c =  <#T##(a -> d)#>
diff --git a/validation-test/compiler_crashers_2/a4aba8624dca192d.swift b/validation-test/compiler_crashers_2/a4aba8624dca192d.swift
new file mode 100644
index 0000000000000..b428744150f2c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a4aba8624dca192d.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","original":"c03f63d6","signature":"swift::TypeChecker::typeCheckParameterDefault(swift::Expr*&, swift::DeclContext*, swift::Type, bool, bool)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<each b, each c>(repeat each b -> each c = {
diff --git a/validation-test/compiler_crashers_2/a517ab621b50bee2.swift b/validation-test/compiler_crashers_2/a517ab621b50bee2.swift
new file mode 100644
index 0000000000000..c3696cca47fbc
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a517ab621b50bee2.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::ResultBuilderTypeRequest::evaluate(swift::Evaluator&, swift::ValueDecl*) const","signatureAssert":"Assertion failed: (!hasTypeParameter() && \"already have an interface type\"), function mapTypeOutOfContext"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@resultBuilder enum a < b { struct c{@a d:
diff --git a/validation-test/compiler_crashers_2/a53b65eef074b0fa.swift b/validation-test/compiler_crashers_2/a53b65eef074b0fa.swift
new file mode 100644
index 0000000000000..5e2bb3385b0b3
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a53b65eef074b0fa.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::constraints::MissingConformanceFailure::diagnoseTypeCannotConform(swift::Type, swift::Type) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a extension a {
+  b { func * (Self= {
diff --git a/validation-test/compiler_crashers_2/a6b3bc1c6dee79bf.swift b/validation-test/compiler_crashers_2/a6b3bc1c6dee79bf.swift
new file mode 100644
index 0000000000000..aef865aadd8ab
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a6b3bc1c6dee79bf.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"901f9c6d","signature":"swift::constraints::ConstraintSystem::getCalleeLocator(swift::constraints::ConstraintLocator*, bool, llvm::function_ref<swift::Type (swift::Expr*)>, llvm::function_ref<swift::Type (swift::Type)>, llvm::function_ref<std::__1::optional<swift::constraints::SelectedOverload> (swift::constraints::ConstraintLocator*)>)","signatureAssert":"Assertion failed: (!fnTy->is<TypeVariableType>()), function operator()"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+let a = [].reduce([]) {
+  0 && a($1 == a
+  $1 {
diff --git a/validation-test/compiler_crashers_2/a7ea7ad030665968.swift b/validation-test/compiler_crashers_2/a7ea7ad030665968.swift
new file mode 100644
index 0000000000000..7c6a771fe6667
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a7ea7ad030665968.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::TypeChecker::checkObjCKeyPathExpr(swift::DeclContext*, swift::KeyPathExpr*, bool)","signatureAssert":"Assertion failed: (!empty()), function front"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+#keyPath(
+print
diff --git a/validation-test/compiler_crashers_2/a7ee60c01ddf9624.swift b/validation-test/compiler_crashers_2/a7ee60c01ddf9624.swift
new file mode 100644
index 0000000000000..328218b21bca3
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a7ee60c01ddf9624.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::LookupResultBuilder::add(swift::ValueDecl*, swift::DeclContext*, swift::ValueDecl*, swift::Type, bool)::'lambda'(swift::ValueDecl*)::operator()(swift::ValueDecl*) const","signatureAssert":"Assertion failed: (IndexOfFirstOuterResult > 0 && \"found outer results without an inner one\"), function add"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a{b} protocol c : a protocol d : c extension d {
+  struct e : d {
+    f {
+      b
diff --git a/validation-test/compiler_crashers_2/a87df2cdd1c39d8f.swift b/validation-test/compiler_crashers_2/a87df2cdd1c39d8f.swift
new file mode 100644
index 0000000000000..e8e05a7b28632
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a87df2cdd1c39d8f.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","signature":"diagSyntacticUseRestrictions(swift::Expr const*, swift::DeclContext const*, bool)::DiagnoseWalker::checkUseOfMetaTypeName(swift::Expr*)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a : Equatable, ExpressibleByStringLiteral {
+}
+{
+  struct b: a {
+    static var c: b
+  }
+  [ b.c == "" , b]
+}
diff --git a/validation-test/compiler_crashers_2/a8c84d1122922f83.swift b/validation-test/compiler_crashers_2/a8c84d1122922f83.swift
new file mode 100644
index 0000000000000..4c301f4bd4a06
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a8c84d1122922f83.swift
@@ -0,0 +1,14 @@
+// {"kind":"typecheck","original":"bee4b7dd","signature":"swift::constraints::ContextualFailure::tryProtocolConformanceFixIt() const","signatureAssert":"Assertion failed: (!missingProtoTypeStrings.empty() && \"type already conforms to all the protocols?\"), function tryProtocolConformanceFixIt"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a<b, c> {
+  associatedtype b
+  associatedtype c
+}
+extension Int: a {
+  struct d<e>: a {
+    typealias b = e
+  }
+  func f() -> a<a, a> {
+    d<Int>(<#expression#>)
+  }
+}
diff --git a/validation-test/compiler_crashers_2/a8ea3386fbf9c28e.swift b/validation-test/compiler_crashers_2/a8ea3386fbf9c28e.swift
new file mode 100644
index 0000000000000..6a8d1dcd7370b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/a8ea3386fbf9c28e.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::Type llvm::function_ref<swift::Type (swift::SubstitutableType*)>::callback_fn<swift::GenericEnvironment::mapElementTypeIntoPackContext(swift::Type) const::$_0>(long, swift::SubstitutableType*)","signatureAssert":"Assertion failed: (!elementEnv || elementEnv == archetype->getGenericEnvironment()), function operator()"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<each b, each c>(d: repeat each b e: repeat each c) {
+  for f  repeat each e {
+    repeat (d
+    f
diff --git a/validation-test/compiler_crashers_2/b2548f4cd9bcd52d.swift b/validation-test/compiler_crashers_2/b2548f4cd9bcd52d.swift
new file mode 100644
index 0000000000000..d3f5cefa01398
--- /dev/null
+++ b/validation-test/compiler_crashers_2/b2548f4cd9bcd52d.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::TypePrinter::visitAnyFunctionTypeParams(llvm::ArrayRef<swift::AnyFunctionType::Param>, bool, llvm::ArrayRef<swift::LifetimeDependenceInfo>)","signatureAssert":"Assertion failed: (flags.isSending() && \"Only valid when sending is enabled\"), function printParameterFlags"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a->String{ b}
+         func b(c : (sending String
diff --git a/validation-test/compiler_crashers_2/b404bf05a5a80274.swift b/validation-test/compiler_crashers_2/b404bf05a5a80274.swift
new file mode 100644
index 0000000000000..6d4f9b84abf4c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/b404bf05a5a80274.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ContextualFailure::getDiagnosticFor(swift::ContextualTypePurpose, swift::Type)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{ struct a func b< c >->c->() var : (inout a)->() = b(
diff --git a/validation-test/compiler_crashers_2/b7d484d056661f0f.swift b/validation-test/compiler_crashers_2/b7d484d056661f0f.swift
new file mode 100644
index 0000000000000..e8bc6d0b817ae
--- /dev/null
+++ b/validation-test/compiler_crashers_2/b7d484d056661f0f.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::TypeTransform<swift::Type::transformRec(llvm::function_ref<std::__1::optional<swift::Type> (swift::TypeBase*)>) const::Transform>::doIt(swift::Type, swift::TypePosition)","signatureAssert":"Assertion failed: (!ty->is<InOutType>() && \"Cannot have InOutType in a tuple\"), function TupleTypeElt"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+[Int : Int](Int) { a, b in a[b b= b * b
diff --git a/validation-test/compiler_crashers_2/b7fa36aa91745be0.swift b/validation-test/compiler_crashers_2/b7fa36aa91745be0.swift
new file mode 100644
index 0000000000000..663aa27aaac22
--- /dev/null
+++ b/validation-test/compiler_crashers_2/b7fa36aa91745be0.swift
@@ -0,0 +1,11 @@
+// {"kind":"emit-sil","original":"af5c6219","signature":"(anonymous namespace)::AvailabilitySet::getConditional(unsigned int) const","signatureAssert":"Assertion failed: (Idx < size() && \"Out-of-bounds Bit access.\"), function operator[]"}
+// RUN: not --crash %target-swift-frontend -emit-sil %s
+struct a<b> {
+  let c: String
+  let d: b
+}
+extension a where b == Void {
+  init() {
+    d <= ()
+  }
+}
diff --git a/validation-test/compiler_crashers_2/b80a659988983457.swift b/validation-test/compiler_crashers_2/b80a659988983457.swift
new file mode 100644
index 0000000000000..3cc0572e850dc
--- /dev/null
+++ b/validation-test/compiler_crashers_2/b80a659988983457.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::Parser::parseStorageRestrictionsAttribute(swift::SourceLoc, swift::SourceLoc)","signatureAssert":"Assertion failed: (Start.isValid() == End.isValid() && \"Start and end should either both be valid or both be invalid!\"), function SourceRange"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@storageRestrictions(
diff --git a/validation-test/compiler_crashers_2/b862de77602e6bcf.swift b/validation-test/compiler_crashers_2/b862de77602e6bcf.swift
new file mode 100644
index 0000000000000..c61bc07b8cf82
--- /dev/null
+++ b/validation-test/compiler_crashers_2/b862de77602e6bcf.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"$s11swiftASTGen19addQueuedDiagnostic20queuedDiagnosticsPtr011perFrontende5StateH04text8severity3loc12categoryName17documentationPath015highlightRangesH0012numHighlightT013fixItsUntypedySv_SvSo16BridgedStringRefVSo0A0O0E4KindVAP9SourceLocVA2NSPyAP15CharSourceRangeVGSgSiSo0Z8ArrayRefVtF"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+// REQUIRES: swift_swift_parser
+class a { @objc ( : ( b
diff --git a/validation-test/compiler_crashers_2/b98d91945bd93d30.swift b/validation-test/compiler_crashers_2/b98d91945bd93d30.swift
new file mode 100644
index 0000000000000..24cda61c6c84f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/b98d91945bd93d30.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::adjustFunctionTypeForConcurrency(swift::AnyFunctionType*, swift::ValueDecl*, swift::DeclContext*, unsigned int, bool, llvm::function_ref<swift::Type (swift::AbstractClosureExpr const*)>, llvm::function_ref<bool (swift::ClosureExpr const*)>, llvm::function_ref<swift::Type (swift::Type)>)","signatureAssert":"Assertion failed: (fnType->getIsolation().isNonIsolated()), function adjustFunctionTypeForConcurrency"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+actor a func b(isolated a...) b
diff --git a/validation-test/compiler_crashers_2/b9f0fa4bd40b5ec8.swift b/validation-test/compiler_crashers_2/b9f0fa4bd40b5ec8.swift
new file mode 100644
index 0000000000000..9a4fe5cbdb0b3
--- /dev/null
+++ b/validation-test/compiler_crashers_2/b9f0fa4bd40b5ec8.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"77effdcf","signature":"swift::TypeBase::getSuperclassForDecl(swift::ClassDecl const*, bool)","signatureAssert":"Assertion failed: (isa<ClassDecl>(nominalDecl) && \"expected a class here\"), function getSuperclassForDecl"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a: b
+  protocol c {
+    associatedtype d
+  }
+  class b: c
+    struct e: a {  f: d
diff --git a/validation-test/compiler_crashers_2/be64bc4123212eee.swift b/validation-test/compiler_crashers_2/be64bc4123212eee.swift
new file mode 100644
index 0000000000000..57deb1849cd6b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/be64bc4123212eee.swift
@@ -0,0 +1,9 @@
+// {"kind":"typecheck","signature":"swift::constraints::RequirementFailure::RequirementFailure(swift::constraints::Solution const&, swift::Type, swift::Type, swift::constraints::ConstraintLocator*)","signatureAssert":"Assertion failed: (AffectedDecl), function RequirementFailure"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a
+  struct b<c
+    extension b where c: a {
+      typealias d<c> =
+    }
+      b<Int>
+.d
diff --git a/validation-test/compiler_crashers_2/bf28fe4f10fb3d0c.swift b/validation-test/compiler_crashers_2/bf28fe4f10fb3d0c.swift
new file mode 100644
index 0000000000000..32aa24893253d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/bf28fe4f10fb3d0c.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ResolvePattern::composeTupleOrParenPattern(swift::ArgumentList*)","signatureAssert":"Assertion failed: (!args->hasAnyInOutArgs()), function composeTupleOrParenPattern"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+switch { case .a(&b
diff --git a/validation-test/compiler_crashers_2/c037334d5426557d.swift b/validation-test/compiler_crashers_2/c037334d5426557d.swift
new file mode 100644
index 0000000000000..da4cca584c30e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c037334d5426557d.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::applySolutionFixes(swift::constraints::Solution const&)","aliases":["swift::constraints::AllowArgumentMismatch::create(swift::constraints::ConstraintSystem&, swift::Type, swift::Type, swift::constraints::ConstraintLocator*)"]}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<each b>(repeat each b, repeat each b)
+a(repeat (
diff --git a/validation-test/compiler_crashers_2/c24f9fc9098e2886.swift b/validation-test/compiler_crashers_2/c24f9fc9098e2886.swift
new file mode 100644
index 0000000000000..d1692c3ef3648
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c24f9fc9098e2886.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::PrintingDiagnosticConsumer::printDiagnostic(swift::SourceManager&, swift::DiagnosticInfo const&)"}
+// RUN: not --crash %target-swift-frontend -typecheck -diagnostic-style=llvm %s
+''
diff --git a/validation-test/compiler_crashers_2/c25aed95f6f6d937.swift b/validation-test/compiler_crashers_2/c25aed95f6f6d937.swift
new file mode 100644
index 0000000000000..573e3f1f4faaa
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c25aed95f6f6d937.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::TypeDecl::getName() const","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  extension {
+    a {
+      func b {
+        super
diff --git a/validation-test/compiler_crashers_2/c2a5da313080f9bb.swift b/validation-test/compiler_crashers_2/c2a5da313080f9bb.swift
new file mode 100644
index 0000000000000..a452b0f8ed428
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c2a5da313080f9bb.swift
@@ -0,0 +1,15 @@
+// {"kind":"typecheck","original":"5c733d48","signature":"getTypeForSymbolRange(swift::rewriting::Symbol const*, swift::rewriting::Symbol const*, llvm::ArrayRef<swift::GenericTypeParamType*>, swift::rewriting::PropertyMap const&)","signatureAssert":"Assertion failed: (std::find(conformsTo.begin(), conformsTo.end(), symbol.getProtocol()) != conformsTo.end()), function getTypeForSymbolRange"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  associatedtype b
+}
+protocol c {
+  associatedtype b
+  var d : b
+  struct e : c {
+d : some a struct f < b : a where b == e.b, g == b.b, h == b > {
+      func
+            i < b>()
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/c3b37ed583f2402b.swift b/validation-test/compiler_crashers_2/c3b37ed583f2402b.swift
new file mode 100644
index 0000000000000..3f8c821d9add7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c3b37ed583f2402b.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::IsBindableVisitor::handleGenericNominalType(swift::NominalTypeDecl*, swift::CanType, swift::CanType)","stackOverflow":true}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a < b protocol
+    c{associatedtype f : a<d> associatedtype d : a<f>} func e < b : c {
+  b.f = b.d
diff --git a/validation-test/compiler_crashers_2/c3d13662d24dc5b4.swift b/validation-test/compiler_crashers_2/c3d13662d24dc5b4.swift
new file mode 100644
index 0000000000000..a10f8185461d7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c3d13662d24dc5b4.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::diagnoseConstantArgumentRequirement(swift::Expr const*, swift::DeclContext const*)::ConstantReqCallWalker::walkToExprPre(swift::Expr*)","signatureAssert":"Assertion failed: (constantIndex < arguments.size() && \"constantIndex exceeds the number of arguments to the function\"), function diagnoseConstantArgumentRequirementOfCall"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  @_semantics("oslog.requires_constant_arguments") func a(b) { a(
diff --git a/validation-test/compiler_crashers_2/c7f6f9dc8e8c9d71.swift b/validation-test/compiler_crashers_2/c7f6f9dc8e8c9d71.swift
new file mode 100644
index 0000000000000..e99ff75d8ec2f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c7f6f9dc8e8c9d71.swift
@@ -0,0 +1,12 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::matchResultBuilder(swift::AnyFunctionRef, swift::Type, swift::Type, swift::constraints::ConstraintKind, swift::Type, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (builder->getAttrs().hasAttribute<ResultBuilderAttr>()), function matchResultBuilder"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  @resultBuilder struct b
+  }
+  struct c < d {
+    init(@b content : () -> d
+  }
+  extension c : a
+    struct b {
+e {
+  c {
diff --git a/validation-test/compiler_crashers_2/c80788f7208dff60.swift b/validation-test/compiler_crashers_2/c80788f7208dff60.swift
new file mode 100644
index 0000000000000..90c97a3ff0cba
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c80788f7208dff60.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","original":"6bb0b020","signature":"swift::KeyPathExpr::getKeyPathType() const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{ let a = \ .b { c} (let c = a
diff --git a/validation-test/compiler_crashers_2/c82707c165c1ebfa.swift b/validation-test/compiler_crashers_2/c82707c165c1ebfa.swift
new file mode 100644
index 0000000000000..85b771fae4231
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c82707c165c1ebfa.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::CallerSideDefaultArgExprRequest::evaluate(swift::Evaluator&, swift::DefaultArgumentExpr*) const","signatureAssert":"Assertion failed: (Loc.isValid()), function getLineAndColumnInBuffer"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@expression macro a (() =
+#b)
+#a
diff --git a/validation-test/compiler_crashers_2/c956e003382cbc94.swift b/validation-test/compiler_crashers_2/c956e003382cbc94.swift
new file mode 100644
index 0000000000000..3c65a22d943f8
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c956e003382cbc94.swift
@@ -0,0 +1,9 @@
+// {"kind":"typecheck","original":"1562769e","signature":"(anonymous namespace)::ConstraintWalker::walkToExprPost(swift::Expr*)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum c
+  func d()  e {
+    if let
+      f = c
+    {
+      switch f {
+      case let a(b) where b
diff --git a/validation-test/compiler_crashers_2/c9616ad936925cb2.swift b/validation-test/compiler_crashers_2/c9616ad936925cb2.swift
new file mode 100644
index 0000000000000..765df4249f820
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c9616ad936925cb2.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::Solution::getFunctionArgApplyInfo(swift::constraints::ConstraintLocator*) const","signatureAssert":"Assertion failed: (!shouldHaveDirectCalleeOverload(call) && \"Should we have resolved a callee for this?\"), function getFunctionArgApplyInfo"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a<b, each c>(d : repeat(b)->each c) { repeat d(e = f
diff --git a/validation-test/compiler_crashers_2/c9bb544b56cd7c73.swift b/validation-test/compiler_crashers_2/c9bb544b56cd7c73.swift
new file mode 100644
index 0000000000000..47ca8db7f5224
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c9bb544b56cd7c73.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","signature":"swift::AbstractStorageDecl::getValueInterfaceType() const","signatureAssert":"Assertion failed: (detail::isPresent(Val) && \"dyn_cast on a non-existent value\"), function dyn_cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a {
+}
+{
+  lazy var b = {
+    c
+  }
+  var c = a
+}
diff --git a/validation-test/compiler_crashers_2/c9ec50236e69e012.swift b/validation-test/compiler_crashers_2/c9ec50236e69e012.swift
new file mode 100644
index 0000000000000..f50d90f7d20a6
--- /dev/null
+++ b/validation-test/compiler_crashers_2/c9ec50236e69e012.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::Verifier::checkSourceRanges(swift::SourceRange, swift::ASTWalker::ParentTy, llvm::function_ref<void ()>)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func == {
+  switch {
+  case.a {
diff --git a/validation-test/compiler_crashers_2/ca5900685b7123ac.swift b/validation-test/compiler_crashers_2/ca5900685b7123ac.swift
new file mode 100644
index 0000000000000..bb7a6a3d332a2
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ca5900685b7123ac.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::SubstitutionMap::get(swift::GenericSignature, swift::InFlightSubstitution&)","signatureAssert":"Assertion failed: ((replacement->hasError() || gp->isParameterPack() == replacement->is<PackType>()) && \"replacement for pack parameter must be a pack type\"), function get"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a < each b { class c protocol d init(e: c & d
diff --git a/validation-test/compiler_crashers_2/cb8022311165d5ef.swift b/validation-test/compiler_crashers_2/cb8022311165d5ef.swift
new file mode 100644
index 0000000000000..08893eeb30676
--- /dev/null
+++ b/validation-test/compiler_crashers_2/cb8022311165d5ef.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::AbstractStorageDecl::getAccessStrategy(swift::AccessSemantics, swift::AccessKind, swift::ModuleDecl*, swift::ResilienceExpansion, std::__1::optional<std::__1::pair<swift::SourceRange, swift::DeclContext const*>>, bool) const","signatureAssert":"Assertion failed: (isa<VarDecl>(storage) && cast<VarDecl>(storage)->isLet() && \"mutation of a immutable variable that isn't a let\"), function getDirectReadWriteAccessStrategy"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a(@_nonEphemeral UnsafeRawPointer) var arr { b a(&arr
diff --git a/validation-test/compiler_crashers_2/cbbc09a1ce53846d.swift b/validation-test/compiler_crashers_2/cbbc09a1ce53846d.swift
new file mode 100644
index 0000000000000..4edac230e5a61
--- /dev/null
+++ b/validation-test/compiler_crashers_2/cbbc09a1ce53846d.swift
@@ -0,0 +1,11 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::getType(swift::ASTNode) const","signatureAssert":"Assertion failed: (found != NodeTypes.end() && \"Expected type to have been set!\"), function getType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@resultBuilder struct b {
+  static buildBlock enum c {
+    @b func d () {
+      switch c {
+      case a?:
+      }
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/cec5966bff434957.swift b/validation-test/compiler_crashers_2/cec5966bff434957.swift
new file mode 100644
index 0000000000000..6821a9e9a7bf0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/cec5966bff434957.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::getAssociatedTypeOfDistributedSystemOfActor(swift::DeclContext*, swift::Identifier)","signatureAssert":"Assertion failed: (Val && \"isa<> used on a null pointer\"), function doit"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Distributed distributed var a{{
diff --git a/validation-test/compiler_crashers_2/d0221822dccb4124.swift b/validation-test/compiler_crashers_2/d0221822dccb4124.swift
new file mode 100644
index 0000000000000..ff33fb075f56d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/d0221822dccb4124.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"00d07d13","signature":"swift::constraints::ConstraintSystem::simplifySameShapeConstraint(swift::Type, swift::Type, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<each b {
+    c(repeat each b)
+  {
+    for    in  c(
diff --git a/validation-test/compiler_crashers_2/d2b0fe8a96146204.swift b/validation-test/compiler_crashers_2/d2b0fe8a96146204.swift
new file mode 100644
index 0000000000000..5d5083484ae7c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/d2b0fe8a96146204.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::rewriting::RequirementMachine::buildRequirementsFromRules(llvm::ArrayRef<unsigned int>, llvm::ArrayRef<unsigned int>, llvm::ArrayRef<swift::GenericTypeParamType*>, bool, std::__1::vector<swift::Requirement, std::__1::allocator<swift::Requirement>>&, std::__1::vector<swift::ProtocolTypeAlias, std::__1::allocator<swift::ProtocolTypeAlias>>&) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a class b class c protocol d {
+  associatedtype e where e : a, e : c, e : b
diff --git a/validation-test/compiler_crashers_2/d3bddfff4812face.swift b/validation-test/compiler_crashers_2/d3bddfff4812face.swift
new file mode 100644
index 0000000000000..cdc232b3b4634
--- /dev/null
+++ b/validation-test/compiler_crashers_2/d3bddfff4812face.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::SubscriptMisuseFailure::diagnoseAsError()","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+"" [.subscript
diff --git a/validation-test/compiler_crashers_2/d40d72be28bfdea6.swift b/validation-test/compiler_crashers_2/d40d72be28bfdea6.swift
new file mode 100644
index 0000000000000..aa0af22f1f2e9
--- /dev/null
+++ b/validation-test/compiler_crashers_2/d40d72be28bfdea6.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ExpandArrayIntoVarargsFailure::tryDropArrayBracketsFixIt(swift::Expr const*) const","signatureAssert":"Assertion failed: (!empty()), function back"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+ExpressibleByDictionaryLiteral([]
diff --git a/validation-test/compiler_crashers_2/d48b4d2e6863049d.swift b/validation-test/compiler_crashers_2/d48b4d2e6863049d.swift
new file mode 100644
index 0000000000000..843891272b182
--- /dev/null
+++ b/validation-test/compiler_crashers_2/d48b4d2e6863049d.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::recordArgumentList(swift::constraints::ConstraintLocator*, swift::ArgumentList*)","signatureAssert":"Assertion failed: (inserted), function recordArgumentList"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol b let b = { (a : b)in switch a { case .c(d(
diff --git a/validation-test/compiler_crashers_2/d4b14cb82157013c.swift b/validation-test/compiler_crashers_2/d4b14cb82157013c.swift
new file mode 100644
index 0000000000000..5d8a68258135f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/d4b14cb82157013c.swift
@@ -0,0 +1,10 @@
+// {"kind":"emit-silgen","original":"941ad66b","signature":"swift::CanTypeWrapperTraits<swift::ReferenceStorageType>::type swift::SILType::castTo<swift::ReferenceStorageType>() const","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -emit-silgen %s
+@available(SwiftStdlib 5.9, *)
+struct a<each b> {
+  var c: (repeat each b) {
+    (repeat {
+      each c
+    })
+  }
+}
diff --git a/validation-test/compiler_crashers_2/d620416563a95ae9.swift b/validation-test/compiler_crashers_2/d620416563a95ae9.swift
new file mode 100644
index 0000000000000..bbbc6b3e4d540
--- /dev/null
+++ b/validation-test/compiler_crashers_2/d620416563a95ae9.swift
@@ -0,0 +1,11 @@
+// {"kind":"typecheck","signature":"swift::constraints::TrailingClosureAmbiguityFailure::diagnoseAsNote()","signatureAssert":"Assertion failed: (!empty()), function back"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  struct a {
+    init ();
+    init ();
+    func callAsFunction< b >(c : b)
+  } ;
+  a {
+  }
+}
diff --git a/validation-test/compiler_crashers_2/da315410694f4a15.swift b/validation-test/compiler_crashers_2/da315410694f4a15.swift
new file mode 100644
index 0000000000000..eed3df6325a7d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/da315410694f4a15.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"extendDepthMap(swift::Expr*, llvm::DenseMap<swift::Expr*, std::__1::pair<unsigned int, swift::Expr*>, llvm::DenseMapInfo<swift::Expr*, void>, llvm::detail::DenseMapPair<swift::Expr*, std::__1::pair<unsigned int, swift::Expr*>>>&)::RecordingTraversal::walkToExprPost(swift::Expr*)","signatureAssert":"Assertion failed: (Closures.back() == CE), function walkToExprPost"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  {
+    func a {
+      if
+      #_hasSymbol(
diff --git a/validation-test/compiler_crashers_2/da64654c0068fd69.swift b/validation-test/compiler_crashers_2/da64654c0068fd69.swift
new file mode 100644
index 0000000000000..77cffb7cf51bf
--- /dev/null
+++ b/validation-test/compiler_crashers_2/da64654c0068fd69.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"d896f132","signature":"swift::constraints::MissingConformanceFailure::MissingConformanceFailure(swift::constraints::Solution const&, swift::constraints::ConstraintLocator*, std::__1::pair<swift::Type, swift::Type>)","signatureAssert":"Assertion failed: (getGenericContext() && \"Affected decl not within a generic context?\"), function RequirementFailure"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+let a =
+  {
+    0 ? [a] : [1&&: <#expression#>]
+  }[<#expression#>]
diff --git a/validation-test/compiler_crashers_2/db89d09981b453c7.swift b/validation-test/compiler_crashers_2/db89d09981b453c7.swift
new file mode 100644
index 0000000000000..f9d9ff7dce94f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/db89d09981b453c7.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","original":"702452ac","signature":"(anonymous namespace)::MultiConformanceChecker::checkAllConformances()","signatureAssert":"Assertion failed: (isa<SubscriptDecl>(Requirement) && \"Unhandled requirement kind\"), function getProtocolRequirementKind"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a: b  protocol b { macro a
diff --git a/validation-test/compiler_crashers_2/dc159d8541132fa2.swift b/validation-test/compiler_crashers_2/dc159d8541132fa2.swift
new file mode 100644
index 0000000000000..c416a0fd34181
--- /dev/null
+++ b/validation-test/compiler_crashers_2/dc159d8541132fa2.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::FunctionType::get(llvm::ArrayRef<swift::AnyFunctionType::Param>, swift::Type, std::__1::optional<swift::ASTExtInfo>)","signatureAssert":"Assertion failed: (isConsistentAboutIsolation(info, params)), function FunctionType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum a {
+  case (b: isolated c)
+}
diff --git a/validation-test/compiler_crashers_2/dc31b2ef4315855a.swift b/validation-test/compiler_crashers_2/dc31b2ef4315855a.swift
new file mode 100644
index 0000000000000..daf161b1a953f
--- /dev/null
+++ b/validation-test/compiler_crashers_2/dc31b2ef4315855a.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::rewriting::RewriteSystem::minimizeRewriteSystem(swift::rewriting::PropertyMap const&)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a: Collection where Element == b!{ associatedtype b: c }
+                        protocol d { associatedtype e where e == Self.b.e associatedtype f: a where f.Element == e }
+                        protocol c { associatedtype e: g associatedtype h: i where h.b == Self protocol i: d protocol g { associatedtype b: c where b.e == Self
diff --git a/validation-test/compiler_crashers_2/dc5f0791705b1cca.swift b/validation-test/compiler_crashers_2/dc5f0791705b1cca.swift
new file mode 100644
index 0000000000000..9ebe731aea572
--- /dev/null
+++ b/validation-test/compiler_crashers_2/dc5f0791705b1cca.swift
@@ -0,0 +1,9 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::getClosureType(swift::ClosureExpr const*) const","signatureAssert":"Assertion failed: (result), function getClosureType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  lazy var a =
+    if <#expression#> {
+      return
+    }
+  a
+}
diff --git a/validation-test/compiler_crashers_2/dd784376d0f127e9.swift b/validation-test/compiler_crashers_2/dd784376d0f127e9.swift
new file mode 100644
index 0000000000000..f590c502d5264
--- /dev/null
+++ b/validation-test/compiler_crashers_2/dd784376d0f127e9.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","signature":"swift::TypeTransform<swift::Type::transformRec(llvm::function_ref<std::__1::optional<swift::Type> (swift::TypeBase*)>) const::Transform>::doIt(swift::Type, swift::TypePosition)","signatureAssert":"Assertion failed: (type->isTypeParameter() && \"Expected a type parameter\"), function requiresProtocol"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  associatedtype b
+  typealias c = a
+}
+struct d : e
+  protocol e : a {
+    associatedtype c where b == c.b
+    associatedtype f = Self
diff --git a/validation-test/compiler_crashers_2/dda1d9031373fa50.swift b/validation-test/compiler_crashers_2/dda1d9031373fa50.swift
new file mode 100644
index 0000000000000..5f2ae9b44c7f1
--- /dev/null
+++ b/validation-test/compiler_crashers_2/dda1d9031373fa50.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","original":"0fdef466","signature":"(anonymous namespace)::ExprRewriter::finishApply(swift::ApplyExpr*, swift::Type, swift::constraints::ConstraintLocatorBuilder, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a func b(c : a) { _openExistential(c do: b
diff --git a/validation-test/compiler_crashers_2/df1e71cd8c428eba.swift b/validation-test/compiler_crashers_2/df1e71cd8c428eba.swift
new file mode 100644
index 0000000000000..8483309551664
--- /dev/null
+++ b/validation-test/compiler_crashers_2/df1e71cd8c428eba.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"b10f3bb6","signature":"swift::Mangle::ASTMangler::appendAnyGenericType(swift::GenericTypeDecl const*, swift::Mangle::ASTMangler::BaseEntitySignature&)","stackOverflow":true}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a
+  extension a where Self == b? {
+    enum b
+      let c: some a
diff --git a/validation-test/compiler_crashers_2/df69d29c5771e948.swift b/validation-test/compiler_crashers_2/df69d29c5771e948.swift
new file mode 100644
index 0000000000000..b9fda05a22cbf
--- /dev/null
+++ b/validation-test/compiler_crashers_2/df69d29c5771e948.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::repairFailures(swift::Type, swift::Type, swift::constraints::ConstraintKind, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, llvm::SmallVectorImpl<swift::constraints::RestrictionOrFix>&, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (Index < Length && \"Invalid index!\"), function operator[]"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a< b , c : Sequence, d >( b, c) where b== c.Element a( ( 0 , [ (0 0), (
diff --git a/validation-test/compiler_crashers_2/e14553980b093c1c.swift b/validation-test/compiler_crashers_2/e14553980b093c1c.swift
new file mode 100644
index 0000000000000..8fa8def95197d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e14553980b093c1c.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::TypeChecker::performTypoCorrection(swift::DeclContext*, swift::DeclRefKind, swift::Type, swift::optionset::OptionSet<swift::NameLookupFlags, unsigned int>, swift::TypoCorrectionResults&, swift::GenericSignature, unsigned int)","signatureAssert":"Assertion failed: (!baseTypeOrNull || !baseTypeOrNull->hasTypeParameter() || genericSig), function performTypoCorrection"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+enum a<b {
+  @propertyWrapper class e {wrappedValue:b var projectedValue: a? {
+      @e var wrappedValue: b wrappedValue.d
diff --git a/validation-test/compiler_crashers_2/e28b0b0aa21817d3.swift b/validation-test/compiler_crashers_2/e28b0b0aa21817d3.swift
new file mode 100644
index 0000000000000..bac3579d2251e
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e28b0b0aa21817d3.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::TypeBase::removeArgumentLabels(unsigned int)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a dynamic subscript(b c: Int) a subscript(b c: Int) a @_dynamicReplacement(for: subscript) subscript(Int) a { }
diff --git a/validation-test/compiler_crashers_2/e2b1640a3c37951d.swift b/validation-test/compiler_crashers_2/e2b1640a3c37951d.swift
new file mode 100644
index 0000000000000..63c469bf9902d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e2b1640a3c37951d.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::Classification::forDeclRef(swift::ConcreteDeclRef, (anonymous namespace)::ConditionalEffectKind, (anonymous namespace)::PotentialEffectReason, swift::SourceLoc, bool, std::__1::optional<swift::EffectKind>)","signatureAssert":"Assertion failed: (!thrownError->hasError()), function forThrows"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+var a : String { get throws(b{
+  a
diff --git a/validation-test/compiler_crashers_2/e40b4406ca551533.swift b/validation-test/compiler_crashers_2/e40b4406ca551533.swift
new file mode 100644
index 0000000000000..3519f10674e88
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e40b4406ca551533.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::setType(swift::ASTNode, swift::Type, swift::constraints::PreparedOverloadBuilder*)","signatureAssert":"Assertion failed: (!node.isNull() && \"Cannot set type information on null node\"), function setType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a let() = {(@a)in
diff --git a/validation-test/compiler_crashers_2/e5940fd2382ce311.swift b/validation-test/compiler_crashers_2/e5940fd2382ce311.swift
new file mode 100644
index 0000000000000..389b123cfc80d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e5940fd2382ce311.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::MissingCallFailure::diagnoseAsError()","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a < each b {
+  init(repeat each b) func c < each d { a<repeat each d, String >(repeat e, {
+    ""
diff --git a/validation-test/compiler_crashers_2/e5dc06197d5ae06b.swift b/validation-test/compiler_crashers_2/e5dc06197d5ae06b.swift
new file mode 100644
index 0000000000000..297ff1476df35
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e5dc06197d5ae06b.swift
@@ -0,0 +1,12 @@
+// {"kind":"typecheck","signature":"swift::Mangle::ASTMangler::appendExistentialLayout(swift::ExistentialLayout const&, swift::GenericSignature, swift::ValueDecl const*)","stackOverflow":true}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a {
+  typealias b = Int
+}
+protocol c {
+  associatedtype b
+}
+extension a where b == Int
+  extension a where Self : c {
+    protocol Int : c {
+d
diff --git a/validation-test/compiler_crashers_2/e69d4d956514d9ef.swift b/validation-test/compiler_crashers_2/e69d4d956514d9ef.swift
new file mode 100644
index 0000000000000..efbbba029d77b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e69d4d956514d9ef.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::ast_scope::NodeAdder::visitBraceStmt(swift::BraceStmt*, swift::ast_scope::ASTScopeImpl*, swift::ast_scope::ScopeCreator&)::'lambda'(swift::ValueDecl*)::operator()(swift::ValueDecl*) const","signatureAssert":"Assertion failed: (Val && \"isa<> used on a null pointer\"), function doit"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+{
+  @abi(var a) subscript->
diff --git a/validation-test/compiler_crashers_2/e714818ef0d04b52.swift b/validation-test/compiler_crashers_2/e714818ef0d04b52.swift
new file mode 100644
index 0000000000000..d758d2d2f466a
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e714818ef0d04b52.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::AssociatedTypeInference::inferAbstractTypeWitnesses(llvm::ArrayRef<swift::AssociatedTypeDecl*>, unsigned int)","signatureAssert":"Assertion failed: (!tyWitness.DefaultedAssocType && \"already recorded a default type witness\"), function addDefaultTypeWitness"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a : b protocol b {
+  typealias c typealias c : = c
diff --git a/validation-test/compiler_crashers_2/e782d1e4d7cf5689.swift b/validation-test/compiler_crashers_2/e782d1e4d7cf5689.swift
new file mode 100644
index 0000000000000..e565cff1cebd0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e782d1e4d7cf5689.swift
@@ -0,0 +1,11 @@
+// {"kind":"typecheck","signature":"swift::constraints::GenericArgumentsMismatchFailure::diagnoseAsError()","signatureAssert":"Assertion failed: (!(purpose == CTP_Unused || purpose == CTP_CannotFail)), function diagnoseAsError"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a<b{
+         wrappedValue: b
+       }
+        @propertyWrapper struct e<b{
+         wrappedValue: b
+       }
+           {
+               @e @a var value = if true
+                 let : e<a<Bool>> = _value
diff --git a/validation-test/compiler_crashers_2/e991ae179ce5e7f6.swift b/validation-test/compiler_crashers_2/e991ae179ce5e7f6.swift
new file mode 100644
index 0000000000000..84aab09f0f29c
--- /dev/null
+++ b/validation-test/compiler_crashers_2/e991ae179ce5e7f6.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::matchFunctionTypes(swift::FunctionType*, swift::FunctionType*, swift::constraints::ConstraintKind, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (Val && \"isa<> used on a null pointer\"), function doit"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+func a b _openExistential((c a
diff --git a/validation-test/compiler_crashers_2/eb83d35f4efc1200.swift b/validation-test/compiler_crashers_2/eb83d35f4efc1200.swift
new file mode 100644
index 0000000000000..a86934961abc5
--- /dev/null
+++ b/validation-test/compiler_crashers_2/eb83d35f4efc1200.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"ada65d78","signature":"swift::rewriting::PropertyBag::getAssociatedType(swift::Identifier)","signatureAssert":"Assertion failed: (assocType != nullptr && \"Need to look harder\"), function getAssociatedType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+a
+protocol b: RangeReplaceableCollection & a  :class a: b
diff --git a/validation-test/compiler_crashers_2/ebe41bf99641e618.swift b/validation-test/compiler_crashers_2/ebe41bf99641e618.swift
new file mode 100644
index 0000000000000..be66d12e69806
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ebe41bf99641e618.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::recordDisjunctionChoice(swift::constraints::ConstraintLocator*, unsigned int)","signatureAssert":"Assertion failed: (inserted), function recordDisjunctionChoice"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a {
+  init! ( b: Int, () -> Int = {
+    }
+() -> Int = a(b : 1) {
diff --git a/validation-test/compiler_crashers_2/ed0d39c475521d4d.swift b/validation-test/compiler_crashers_2/ed0d39c475521d4d.swift
new file mode 100644
index 0000000000000..a2a64a902be78
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ed0d39c475521d4d.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::LValueType::get(swift::Type)","signatureAssert":"Assertion failed: (!objectTy->is<LValueType>() && !objectTy->is<InOutType>() && \"cannot have 'inout' or @lvalue wrapped inside an @lvalue\"), function get"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+a!!= 1
diff --git a/validation-test/compiler_crashers_2/ee01b0cddb8c5936.swift b/validation-test/compiler_crashers_2/ee01b0cddb8c5936.swift
new file mode 100644
index 0000000000000..174add6f19f6d
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ee01b0cddb8c5936.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::AssociatedTypeInference::inferTypeWitnessesViaValueWitnesses(llvm::SetVector<swift::AssociatedTypeDecl*, llvm::SmallVector<swift::AssociatedTypeDecl*, 0u>, llvm::DenseSet<swift::AssociatedTypeDecl*, llvm::DenseMapInfo<swift::AssociatedTypeDecl*, void>>, 0u> const&)","signatureAssert":"Assertion failed: (!result.second->hasTypeParameter() || selfTy && \"We should only see unresolved type witnesses on the \" \"right-hand side of a binding when the value witness came from a \" \"protocol extension\"), function getPotentialTypeWitnessesFromRequirement"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a{associatedtype b} protocol c : RandomAccessCollection struct d < e
+    : a,
+    f {
+  g {
+    struct h : c {
+      typealias i = e.b subscript(i) f
diff --git a/validation-test/compiler_crashers_2/ee271b56888b63fa.swift b/validation-test/compiler_crashers_2/ee271b56888b63fa.swift
new file mode 100644
index 0000000000000..341aff7ccd874
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ee271b56888b63fa.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::InFlightSubstitution::projectLaneFromPackType(swift::Type, unsigned int)","signatureAssert":"Assertion failed: (index < substPackType->getNumElements() && \"replacement for pack parameter did not have the right \" \"size for expansion\"), function projectLaneFromPackType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+typealias a< each b > = ( < struct c< each d {
+           typealias e< each b > = (repeat a< each d, each b >
+          struct f typealias 1 = c .e<>
diff --git a/validation-test/compiler_crashers_2/ef29fe0d11b57662.swift b/validation-test/compiler_crashers_2/ef29fe0d11b57662.swift
new file mode 100644
index 0000000000000..a3cddbf8bdfa0
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ef29fe0d11b57662.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"fixMissingArguments(swift::constraints::ConstraintSystem&, swift::ASTNode, llvm::SmallVectorImpl<swift::AnyFunctionType::Param>&, llvm::ArrayRef<swift::AnyFunctionType::Param>, unsigned int, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (Index < Length && \"Invalid index!\"), function operator[]"}
+// RUN: not --crash %target-swift-frontend -typecheck -swift-version 6 %s
+func a((Int, Int, Int)) a > {
+  b, c in
diff --git a/validation-test/compiler_crashers_2/ef678247b5bec562.swift b/validation-test/compiler_crashers_2/ef678247b5bec562.swift
new file mode 100644
index 0000000000000..f35f9e561a5e6
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ef678247b5bec562.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"4d90fbe2","signature":"swift::constraints::AllowTypeOrInstanceMemberFailure::diagnoseAsError()","signatureAssert":"Assertion failed: (TypeDC->getContextKind() == DeclContextKind::AbstractFunctionDecl && \"Expected function decl context for initializer!\"), function diagnoseAsError","splits":[0]}
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: not --crash %target-swift-frontend -typecheck %t/main.swift %t/x1.swift
+//--- main.swift
+
+//--- x1.swift
+let <#pattern#>: LazyMapCollection = .lazy
diff --git a/validation-test/compiler_crashers_2/ef6fa06269073e94.swift b/validation-test/compiler_crashers_2/ef6fa06269073e94.swift
new file mode 100644
index 0000000000000..f92182c436a0b
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ef6fa06269073e94.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ImplicitSelfUsageChecker::isClosureRequiringSelfQualification(swift::AbstractClosureExpr const*, bool)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a : ExpressibleByBooleanLiteral {
+  c(d : Bool -> (
+}
+{
+  a(true).c {
+  b in
diff --git a/validation-test/compiler_crashers_2/efd413faa5b859c9.swift b/validation-test/compiler_crashers_2/efd413faa5b859c9.swift
new file mode 100644
index 0000000000000..b5af74f7ec4a2
--- /dev/null
+++ b/validation-test/compiler_crashers_2/efd413faa5b859c9.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::recordOpenedType(swift::constraints::ConstraintLocator*, llvm::ArrayRef<std::__1::pair<swift::GenericTypeParamType*, swift::TypeVariableType*>>, swift::constraints::PreparedOverloadBuilder*)","signatureAssert":"Assertion failed: (inserted), function recordOpenedType"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct b let c = { (a : b)in switch a { case .d(... e
diff --git a/validation-test/compiler_crashers_2/efe245e1832e7ed7.swift b/validation-test/compiler_crashers_2/efe245e1832e7ed7.swift
new file mode 100644
index 0000000000000..22de8cd5a64ee
--- /dev/null
+++ b/validation-test/compiler_crashers_2/efe245e1832e7ed7.swift
@@ -0,0 +1,9 @@
+// {"kind":"typecheck","original":"eece2094","signature":"swift::constraints::ConstraintSystem::finalize()"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a {
+  var
+    b : () -> some Any = {
+      b()
+      c
+  }
+}
diff --git a/validation-test/compiler_crashers_2/f1419d3f3c2fe6b9.swift b/validation-test/compiler_crashers_2/f1419d3f3c2fe6b9.swift
new file mode 100644
index 0000000000000..9ee6da3659ee3
--- /dev/null
+++ b/validation-test/compiler_crashers_2/f1419d3f3c2fe6b9.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::Mangle::ASTMangler::appendExtension(swift::ExtensionDecl const*, swift::Mangle::ASTMangler::BaseEntitySignature&, llvm::StringRef)","stackOverflow":true}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+extension Collection where Self : a {
+  struct Index protocol a
diff --git a/validation-test/compiler_crashers_2/f3ef80da3095d840.swift b/validation-test/compiler_crashers_2/f3ef80da3095d840.swift
new file mode 100644
index 0000000000000..9f96893a4ecc3
--- /dev/null
+++ b/validation-test/compiler_crashers_2/f3ef80da3095d840.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"decomposePartialApplyThunk(swift::ApplyExpr*, swift::Expr*)","signatureAssert":"Assertion failed: (false && \"Malformed curry thunk?\"), function getUnwrappedCurryThunkExpr"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a { associatedtype b associatedtype c where c == Dictionary<String, b> func d -> c? }
+                  let e: a e.d
diff --git a/validation-test/compiler_crashers_2/f4e3977ec1f2aee1.swift b/validation-test/compiler_crashers_2/f4e3977ec1f2aee1.swift
new file mode 100644
index 0000000000000..f620007a9fc64
--- /dev/null
+++ b/validation-test/compiler_crashers_2/f4e3977ec1f2aee1.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::Decl::attachParsedAttrs(swift::DeclAttributes)","signatureAssert":"Assertion failed: (!OriginalDeclaration && \"Original declaration cannot have already been set\"), function setOriginalDeclaration"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@differentiable () let a, b
diff --git a/validation-test/compiler_crashers_2/f676bef08c1061da.swift b/validation-test/compiler_crashers_2/f676bef08c1061da.swift
new file mode 100644
index 0000000000000..a72fbc7e1fbc5
--- /dev/null
+++ b/validation-test/compiler_crashers_2/f676bef08c1061da.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::rewriting::PropertyBag::getAssociatedType(swift::Identifier)"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol b : a{typealias a} protocol a : b {
+  typealias a
diff --git a/validation-test/compiler_crashers_2/f6e25531c0e51b62.swift b/validation-test/compiler_crashers_2/f6e25531c0e51b62.swift
new file mode 100644
index 0000000000000..96fd8f41d6ef7
--- /dev/null
+++ b/validation-test/compiler_crashers_2/f6e25531c0e51b62.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::RequirementFailure::RequirementFailure(swift::constraints::Solution const&, swift::Type, swift::Type, swift::constraints::ConstraintLocator*)","signatureAssert":"Assertion failed: (getRequirementDC() && \"Couldn't find where the requirement came from?\"), function RequirementFailure"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a{associatedtype b} extension a where b == {
+  protocol c var d : c {
+    d
diff --git a/validation-test/compiler_crashers_2/f795c2f5f8d23312.swift b/validation-test/compiler_crashers_2/f795c2f5f8d23312.swift
new file mode 100644
index 0000000000000..eca245fb9e824
--- /dev/null
+++ b/validation-test/compiler_crashers_2/f795c2f5f8d23312.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","original":"c950cc2e","signature":"(anonymous namespace)::MultiConformanceChecker::checkAllConformances()","signatureAssert":"Assertion failed: (!type->hasTypeParameter() && \"no generic environment provided for type with type parameters\"), function mapTypeIntoContext"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<b
+  protocol c {
+    associatedtype d
+    typealias d = a
+    struct e: c
diff --git a/validation-test/compiler_crashers_2/f864514671159f38.swift b/validation-test/compiler_crashers_2/f864514671159f38.swift
new file mode 100644
index 0000000000000..3b9a1c1567272
--- /dev/null
+++ b/validation-test/compiler_crashers_2/f864514671159f38.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::MissingContextualConformanceFailure::diagnoseAsError()","signatureAssert":"Assertion failed: (Context != CTP_Unused), function diagnoseAsError"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a }
+                       {
+                      b -> a? in return .c<d e
diff --git a/validation-test/compiler_crashers_2/f954ff86c7921441.swift b/validation-test/compiler_crashers_2/f954ff86c7921441.swift
new file mode 100644
index 0000000000000..a851fd8dbc9ef
--- /dev/null
+++ b/validation-test/compiler_crashers_2/f954ff86c7921441.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"34ac8b6c","signature":"swift::constraints::Constraint::Constraint(swift::FunctionType*, swift::Type, unsigned int, swift::DeclContext*, swift::constraints::ConstraintLocator*, llvm::SmallPtrSetImpl<swift::TypeVariableType*>&)","signatureAssert":"Assertion failed: (isAdmissibleType(appliedFn)), function Constraint"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+class a < b > {
+  func
+    c < let b : a >() {
+      b > 0
+  }
+}
diff --git a/validation-test/compiler_crashers_2/fda9a61a6187b061.swift b/validation-test/compiler_crashers_2/fda9a61a6187b061.swift
new file mode 100644
index 0000000000000..8277b92fba447
--- /dev/null
+++ b/validation-test/compiler_crashers_2/fda9a61a6187b061.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::rewriting::RewriteSystem::decomposeTermIntoConformanceRuleLeftHandSides(swift::rewriting::MutableTerm, llvm::SmallVectorImpl<unsigned int>&) const"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a{associatedtype b : c} protocol c { associatedtype d }
+struct e : a struct f < g : a, h : c where g.b.d == Int extension f where g == e
diff --git a/validation-test/compiler_crashers_2/fef90fa2b91e98ff.swift b/validation-test/compiler_crashers_2/fef90fa2b91e98ff.swift
new file mode 100644
index 0000000000000..dfe17aeade848
--- /dev/null
+++ b/validation-test/compiler_crashers_2/fef90fa2b91e98ff.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::ExistentialArchetypeType::get(swift::CanType)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+protocol a where b == Self
+  protocol c : a where Self
+  : CustomStringConvertible
+    var d e c.description
diff --git a/validation-test/compiler_crashers_2/ff396e9dd5fce33e.swift b/validation-test/compiler_crashers_2/ff396e9dd5fce33e.swift
new file mode 100644
index 0000000000000..a1a0f6314f766
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ff396e9dd5fce33e.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::Parser::parseList(swift::tok, swift::SourceLoc, swift::SourceLoc&, bool, swift::DiagRef, llvm::function_ref<swift::ParserStatus ()>)","signatureAssert":"Assertion failed: (Status.isErrorOrHasCompletion() && \"no progress without error\"), function parseListItem"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@attached(conformances: ,
diff --git a/validation-test/compiler_crashers_2/ff596376e8eadba5.swift b/validation-test/compiler_crashers_2/ff596376e8eadba5.swift
new file mode 100644
index 0000000000000..38d78b06a6f57
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ff596376e8eadba5.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"checkRequirementsImpl(llvm::ArrayRef<swift::Requirement>, bool)","signatureAssert":"Assertion failed: (!firstType->hasTypeVariable()), function checkRequirementsImpl"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+struct a<b: ~Copyable
+  extension a: Copyable where b: Copyable
+    let c  0 as a
+...
diff --git a/validation-test/compiler_crashers_2/ffc098188a1c39ca.swift b/validation-test/compiler_crashers_2/ffc098188a1c39ca.swift
new file mode 100644
index 0000000000000..700d1c9766db2
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ffc098188a1c39ca.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","signature":"createPropertyStoreOrCallSuperclassSetter(swift::AccessorDecl*, swift::Expr*, swift::AbstractStorageDecl*, (anonymous namespace)::TargetImpl, llvm::SmallVectorImpl<swift::ASTNode>&, swift::ASTContext&)","signatureAssert":"Assertion failed: (destType->getOptionalObjectType()), function createPropertyStoreOrCallSuperclassSetter"}
+// RUN: not --crash %target-swift-frontend -typecheck %s
+@propertyWrapper struct a < b {
+  wrappedValue : b static subscript<c>(_enclosingInstance d
+                                       : c, wrapped e
+                                       : ReferenceWritableKeyPath<c, b>
+                                           storage f
+                                       : ReferenceWritableKeyPath<c, Self>) Self
+} class g {
+  @a h = 7
diff --git a/validation-test/compiler_crashers_2/ffec68ff0b7c2e5a.swift b/validation-test/compiler_crashers_2/ffec68ff0b7c2e5a.swift
new file mode 100644
index 0000000000000..8e8e23e335215
--- /dev/null
+++ b/validation-test/compiler_crashers_2/ffec68ff0b7c2e5a.swift
@@ -0,0 +1,10 @@
+// {"kind":"emit-silgen","original":"91fe640b","signature":"swift::Lowering::TypeConverter::makeConstantInterfaceType(swift::SILDeclRef)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not --crash %target-swift-frontend -emit-silgen %s
+@propertyWrapper struct a<b> {
+  init(wrappedValue: b...) {
+  }
+  var wrappedValue: b
+}
+class c {
+  @a var d = 2
+}
diff --git a/validation-test/compiler_crashers_2/issue-80657.swift b/validation-test/compiler_crashers_2/issue-80657.swift
new file mode 100644
index 0000000000000..f5be37a2d20c4
--- /dev/null
+++ b/validation-test/compiler_crashers_2/issue-80657.swift
@@ -0,0 +1,18 @@
+// {"signature":"(anonymous namespace)::Verifier::verifyChecked(swift::VarDecl*)"}
+// RUN: not --crash %target-swift-frontend -emit-sil %s
+
+// https://github.com/swiftlang/swift/issues/80657
+enum E {
+  case e
+
+  static func foo() {
+    _ = { [self] in
+      switch e {
+      case e:
+        break
+      default:
+        break
+      }
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2/issue-81834.swift b/validation-test/compiler_crashers_2/issue-81834.swift
new file mode 100644
index 0000000000000..ffb6f51411a38
--- /dev/null
+++ b/validation-test/compiler_crashers_2/issue-81834.swift
@@ -0,0 +1,8 @@
+// RUN: not --crash %target-swift-frontend -typecheck -library-level api %s
+// REQUIRES: OS=macosx
+
+// https://github.com/swiftlang/swift/issues/81834
+public class C {
+  public subscript() -> Int {
+    get {
+      extension C {}
diff --git a/validation-test/compiler_crashers_2/lit.local.cfg b/validation-test/compiler_crashers_2/lit.local.cfg
new file mode 100644
index 0000000000000..0f7012126c4f3
--- /dev/null
+++ b/validation-test/compiler_crashers_2/lit.local.cfg
@@ -0,0 +1,2 @@
+if "asserts" not in config.available_features:
+    config.unsupported = True
diff --git a/validation-test/compiler_crashers_2_fixed/0122-rdar27383752.swift b/validation-test/compiler_crashers_2_fixed/0122-rdar27383752.swift
index 01b1e56baad4b..1353a5ad7e6fe 100644
--- a/validation-test/compiler_crashers_2_fixed/0122-rdar27383752.swift
+++ b/validation-test/compiler_crashers_2_fixed/0122-rdar27383752.swift
@@ -27,7 +27,7 @@ class Bar<T>: NSObject {
 
 @available(macOS 10.12, *)
 extension Bar: NSFetchedResultsControllerDelegate {
-    // expected-error@-1 {{conformance of generic class 'Bar<T>' to @objc protocol 'NSFetchedResultsControllerDelegate' cannot be in an extension}}
+    // expected-error@-1 {{conformance of generic class 'Bar<T>' to '@objc' protocol 'NSFetchedResultsControllerDelegate' cannot be in an extension}}
     @nonobjc func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
     }
 }
diff --git a/validation-test/compiler_crashers_2_fixed/0144-issue-49620.swift b/validation-test/compiler_crashers_2_fixed/0144-issue-49620.swift
index ac13b1d38d3f1..f03131dbc0a8d 100644
--- a/validation-test/compiler_crashers_2_fixed/0144-issue-49620.swift
+++ b/validation-test/compiler_crashers_2_fixed/0144-issue-49620.swift
@@ -28,6 +28,6 @@ class Bar: Cl {
 
 // CHECK-LABEL: sil hidden @$s4main5crash4barsSbAA8GenClassCyAA3BarCG_tF
 func crash(bars: GenClass<Bar>) -> Bool {
-    // CHECK: apply [[FN:%.*]]<Bar, [Bar]>
+    // CHECK: apply [[FN:%.*]]<Bar, Array<Bar>>
     return Array(bars.filter { $0.x == nil }).isEmpty
 }
diff --git a/validation-test/compiler_crashers_2_fixed/0161-issue-49119.swift b/validation-test/compiler_crashers_2_fixed/0161-issue-49119.swift
index 768d858b6633f..f848a412abdac 100644
--- a/validation-test/compiler_crashers_2_fixed/0161-issue-49119.swift
+++ b/validation-test/compiler_crashers_2_fixed/0161-issue-49119.swift
@@ -9,10 +9,8 @@ protocol P {
 struct Type<Param> {}
 extension Type: P where Param: P, Param.A == Type<Param> {
   // expected-error@-1 {{extension of generic struct 'Type' has self-referential generic requirements}}
-  // expected-note@-2 {{through reference here}}
+  // expected-note@-2 2 {{through reference here}}
   // expected-error@-3 {{type 'Type<Param>' does not conform to protocol 'P'}}
   // expected-note@-4 {{add stubs for conformance}}
   typealias A = Param
-  // expected-note@-1 3{{through reference here}}
-  // expected-note@-2 {{possibly intended match 'Type<Param>.A' (aka 'Param') does not conform to 'P'}}
 }
diff --git a/validation-test/compiler_crashers_2_fixed/0217ed2d301f5d7b.swift b/validation-test/compiler_crashers_2_fixed/0217ed2d301f5d7b.swift
new file mode 100644
index 0000000000000..1ff01f3b60eb5
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/0217ed2d301f5d7b.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"679d3d53","signature":"(anonymous namespace)::PrintAST::visit(swift::Decl*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+extension () {
+  class let a
+}
diff --git a/validation-test/compiler_crashers_2_fixed/03ac172bc4a98f31.swift b/validation-test/compiler_crashers_2_fixed/03ac172bc4a98f31.swift
new file mode 100644
index 0000000000000..30b29c034dbe0
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/03ac172bc4a98f31.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","original":"73696db0","signature":"swift::GenericSignatureImpl::isReducedType(swift::Type) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+a
+struct b<c
+  extension b: BidirectionalCollection where c: a
+    protocol a: BidirectionalCollection where SubSequence == b<Self> {
+d
diff --git a/validation-test/compiler_crashers_2_fixed/078aab8ab466b66a.swift b/validation-test/compiler_crashers_2_fixed/078aab8ab466b66a.swift
new file mode 100644
index 0000000000000..315bb7d79a3af
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/078aab8ab466b66a.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::openGenericParameters(swift::DeclContext*, swift::GenericSignature, llvm::SmallVectorImpl<std::__1::pair<swift::GenericTypeParamType*, swift::TypeVariableType*>>&, swift::constraints::ConstraintLocatorBuilder, swift::constraints::PreparedOverloadBuilder*)","signatureAssert":"Assertion failed: (sig), function openGenericParameters"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a<b
+  func c -> d
+  typealias c  :  a
+c
diff --git a/validation-test/compiler_crashers_2_fixed/1470917329979c9a.swift b/validation-test/compiler_crashers_2_fixed/1470917329979c9a.swift
new file mode 100644
index 0000000000000..c7f9b51c8a1ae
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/1470917329979c9a.swift
@@ -0,0 +1,7 @@
+// {"signature":"swift::PackExpansionType::PackExpansionType(swift::Type, swift::Type, swift::RecursiveTypeProperties, swift::ASTContext const*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a < each b {
+  struct c {
+          d : (repeat(each b
+  func e {
+          c(&0
diff --git a/validation-test/compiler_crashers_2_fixed/14b6ac8674b84f44.swift b/validation-test/compiler_crashers_2_fixed/14b6ac8674b84f44.swift
new file mode 100644
index 0000000000000..60c336e8529e5
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/14b6ac8674b84f44.swift
@@ -0,0 +1,4 @@
+// {"signature":"(anonymous namespace)::ABIDependencyEvaluator::computeABIDependenciesForModule(swift::ModuleDecl*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+switch {
+case init
diff --git a/validation-test/compiler_crashers_2_fixed/16638651735c2c8.swift b/validation-test/compiler_crashers_2_fixed/16638651735c2c8.swift
new file mode 100644
index 0000000000000..6dcdbb22b8fe9
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/16638651735c2c8.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::TypeChecker::checkProtocolSelfRequirements(swift::ValueDecl*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a {
+  associatedtype b
+  func c () where b : AnyObject
+}
diff --git a/validation-test/compiler_crashers_2_fixed/174f557922f5c3cc.swift b/validation-test/compiler_crashers_2_fixed/174f557922f5c3cc.swift
new file mode 100644
index 0000000000000..72c539f629e14
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/174f557922f5c3cc.swift
@@ -0,0 +1,16 @@
+// {"kind":"typecheck","original":"2fdf1565","signature":"(anonymous namespace)::TypeSubstituter::transformDependentMemberType(swift::DependentMemberType*, swift::TypePosition)","stackOverflow":true}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a {
+  typealias b = c
+  associatedtype d: b
+  associatedtype J: Sequence = e<Self> where J.Element == d.f
+}
+protocol c {
+  associatedtype f
+}
+struct g<h>: a {
+  struct d
+  }
+  struct e<i: a>: Sequence {
+    struct Iterator: IteratorProtocol {
+      typealias Element = i.d.f
diff --git a/validation-test/compiler_crashers_2_fixed/1a9cf8aaa2cfa83f.swift b/validation-test/compiler_crashers_2_fixed/1a9cf8aaa2cfa83f.swift
new file mode 100644
index 0000000000000..b08add06cc2fb
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/1a9cf8aaa2cfa83f.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"diagnoseInvalidObjCName(swift::ValueDecl*, swift::ObjCAttr*)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+@objcMembers class a open extension a {
+  func 0.0
diff --git a/validation-test/compiler_crashers_2_fixed/1b94fce977ad935d.swift b/validation-test/compiler_crashers_2_fixed/1b94fce977ad935d.swift
new file mode 100644
index 0000000000000..c84d709a25d98
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/1b94fce977ad935d.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"printDifferentiableAttrArguments(swift::DifferentiableAttr const*, swift::ASTPrinter&, swift::PrintOptions const&, swift::Decl const*, bool)","signatureAssert":"Assertion failed: (original && \"Must resolve original declaration\"), function printDifferentiableAttrArguments"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a(@differentiable _ =
diff --git a/validation-test/compiler_crashers_2_fixed/1c4f5ed8bb743453.swift b/validation-test/compiler_crashers_2_fixed/1c4f5ed8bb743453.swift
new file mode 100644
index 0000000000000..567cb0fb4f627
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/1c4f5ed8bb743453.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::Parser::parseNewDeclAttribute(swift::DeclAttributes&, swift::SourceLoc, swift::DeclAttrKind, bool)::$_4::operator()() const"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a {
+  class override b
diff --git a/validation-test/compiler_crashers_2_fixed/1cafc0c1955e56b5.swift b/validation-test/compiler_crashers_2_fixed/1cafc0c1955e56b5.swift
new file mode 100644
index 0000000000000..876a2251555c7
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/1cafc0c1955e56b5.swift
@@ -0,0 +1,12 @@
+// {"kind":"typecheck","signature":"swift::MakeAbstractConformanceForGenericType::operator()(swift::InFlightSubstitution&, swift::Type, swift::ProtocolDecl*) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol A {}
+struct C<T: A> {}
+protocol E {
+    associatedtype F
+    func g<T>(_: C<T>) where F == T
+}
+struct H: E {
+    typealias F = ()
+    func g<T>(_: C<T>) {}
+}
diff --git a/validation-test/compiler_crashers_2_fixed/1f1b9ed16e283e76.swift b/validation-test/compiler_crashers_2_fixed/1f1b9ed16e283e76.swift
new file mode 100644
index 0000000000000..1365c7e0535ea
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/1f1b9ed16e283e76.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::LazyStoragePropertyRequest::evaluate(swift::Evaluator&, swift::VarDecl*) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a {
+  lazy(b, c) {
diff --git a/validation-test/compiler_crashers_2_fixed/1f6ae695bebb359b.swift b/validation-test/compiler_crashers_2_fixed/1f6ae695bebb359b.swift
new file mode 100644
index 0000000000000..d92bde030d358
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/1f6ae695bebb359b.swift
@@ -0,0 +1,3 @@
+// {"signature":"makeBinOp(swift::ASTContext&, swift::Expr*, swift::Expr*, swift::Expr*, swift::PrecedenceGroupDecl*, bool)"}
+// RUN: not %target-swift-frontend -typecheck %s
+let a= switch a { case &b as? b
diff --git a/validation-test/compiler_crashers_2_fixed/1fb63f2dc87bc9b9.swift b/validation-test/compiler_crashers_2_fixed/1fb63f2dc87bc9b9.swift
new file mode 100644
index 0000000000000..763f8bacf18b1
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/1fb63f2dc87bc9b9.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::Parser::parseDecl(bool, bool, llvm::function_ref<void (swift::Decl*)>, bool)"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a { class override ( override
diff --git a/validation-test/compiler_crashers_2_fixed/20bfa44b864d1f2.swift b/validation-test/compiler_crashers_2_fixed/20bfa44b864d1f2.swift
new file mode 100644
index 0000000000000..57ebd46381322
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/20bfa44b864d1f2.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"8fe2aedb","signature":"makeBinOp(swift::ASTContext&, swift::Expr*, swift::Expr*, swift::Expr*, swift::PrecedenceGroupDecl*, bool)"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  (a: b) in
+  switch a {
+  case c -> _:
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/22119c306663e633.swift b/validation-test/compiler_crashers_2_fixed/22119c306663e633.swift
new file mode 100644
index 0000000000000..719b833fb260d
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/22119c306663e633.swift
@@ -0,0 +1,8 @@
+// {"signature":"swift::NamingPatternRequest::evaluate(swift::Evaluator&, swift::VarDecl*) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  let a = $0.c ;
+  switch a {
+    case let \ (b) where b:
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/259dac55924ef426.swift b/validation-test/compiler_crashers_2_fixed/259dac55924ef426.swift
new file mode 100644
index 0000000000000..beaa9da85e046
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/259dac55924ef426.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::GenericContext::getGenericParams() const"}
+// RUN: not %target-swift-frontend -typecheck %s
+typealias a = () extension a : Comparable
diff --git a/validation-test/compiler_crashers_2_fixed/2617a198505b47e4.swift b/validation-test/compiler_crashers_2_fixed/2617a198505b47e4.swift
new file mode 100644
index 0000000000000..9147add3fa74f
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/2617a198505b47e4.swift
@@ -0,0 +1,6 @@
+// {"signature":"swift::rewriting::RequirementMachine::getReducedShape(swift::Type, llvm::ArrayRef<swift::GenericTypeParamType*>) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a{ b < c > (c, _ : c}
+         protocol d : a{
+  b<c : e>(c, c.c) protocol e {
+    associatedtype c struct f : d
diff --git a/validation-test/compiler_crashers_2_fixed/26193e19e8973c86.swift b/validation-test/compiler_crashers_2_fixed/26193e19e8973c86.swift
new file mode 100644
index 0000000000000..ac6a0f3423021
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/26193e19e8973c86.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"01146903","signature":"swift::NamingPatternRequest::evaluate(swift::Evaluator&, swift::VarDecl*) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+switch  {
+case let .a -> b b
diff --git a/validation-test/compiler_crashers_2_fixed/2819a60354d8389.swift b/validation-test/compiler_crashers_2_fixed/2819a60354d8389.swift
new file mode 100644
index 0000000000000..2f1cac7c39ad2
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/2819a60354d8389.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::rewriting::PropertyMap::addSuperclassProperty(swift::rewriting::Term, swift::rewriting::Symbol, unsigned int)"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a < b class c : a func d < b where b : a<Int>, b : c
diff --git a/validation-test/compiler_crashers_2_fixed/28db756e678d736.swift b/validation-test/compiler_crashers_2_fixed/28db756e678d736.swift
new file mode 100644
index 0000000000000..2c696cdf82813
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/28db756e678d736.swift
@@ -0,0 +1,11 @@
+// {"kind":"emit-silgen","signature":"swift::Lowering::SILGenModule::useConformance(swift::ProtocolConformanceRef)"}
+// RUN: not %target-swift-frontend -emit-silgen %s
+protocol a {
+}
+struct b<c: a> {
+}
+extension [b<Int>] {
+  func d() {
+    first
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/2ae771dc466f1acc.swift b/validation-test/compiler_crashers_2_fixed/2ae771dc466f1acc.swift
new file mode 100644
index 0000000000000..94fbd3e299fbb
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/2ae771dc466f1acc.swift
@@ -0,0 +1,15 @@
+// {"kind":"typecheck","original":"f0cca09d","signature":"swift::ASTWalker::PostWalkResult<swift::ArrayToPointerExpr*> (anonymous namespace)::Verifier::dispatchVisitPost<swift::ArrayToPointerExpr*>(swift::ArrayToPointerExpr*)"}
+// RUN: %target-typecheck-verify-swift
+struct a {
+  var b: String
+}
+func c<d>(e: PartialKeyPath<d>, _: UnsafePointer<d> ...) {
+  func f(i: UnsafePointer<Int64>) {
+    i.withMemoryRebound(to: a.self, capacity: 2) { g in
+      for h in 0 ..< 2 {
+        var elt = g[h]
+        c(e: \.b, &elt)
+      }
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/2d564dafb1f91.swift b/validation-test/compiler_crashers_2_fixed/2d564dafb1f91.swift
new file mode 100644
index 0000000000000..bd86784965f9a
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/2d564dafb1f91.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::getTypeOfMemberReference(swift::Type, swift::ValueDecl*, swift::DeclContext*, bool, swift::FunctionRefInfo, swift::constraints::ConstraintLocator*, llvm::SmallVectorImpl<std::__1::pair<swift::GenericTypeParamType*, swift::TypeVariableType*>>*, swift::constraints::PreparedOverloadBuilder*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a {
+  macro b()
+  var c = b
+}
diff --git a/validation-test/compiler_crashers_2_fixed/2d5e95ea862946ed.swift b/validation-test/compiler_crashers_2_fixed/2d5e95ea862946ed.swift
new file mode 100644
index 0000000000000..cf239d1280ded
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/2d5e95ea862946ed.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ExprWalker::walkToExprPost(swift::Expr*)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a {
+  {
+    \ b() a
diff --git a/validation-test/compiler_crashers_2_fixed/2e698e9f7b48e8c.swift b/validation-test/compiler_crashers_2_fixed/2e698e9f7b48e8c.swift
new file mode 100644
index 0000000000000..3c4b2471c9867
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/2e698e9f7b48e8c.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::constraints::ConstraintSystem::simplifyRestrictedConstraintImpl(swift::constraints::ConversionRestrictionKind, swift::Type, swift::Type, swift::constraints::ConstraintKind, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, swift::constraints::ConstraintLocatorBuilder)"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a < b struct c func d .0 c<a> struct c < a, e
diff --git a/validation-test/compiler_crashers_2_fixed/34a73a7299992de3.swift b/validation-test/compiler_crashers_2_fixed/34a73a7299992de3.swift
new file mode 100644
index 0000000000000..562609e28092a
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/34a73a7299992de3.swift
@@ -0,0 +1,3 @@
+// {"signature":"(anonymous namespace)::OpaqueUnderlyingTypeChecker::check()"}
+// RUN: not %target-swift-frontend -typecheck %s
+Array {
diff --git a/validation-test/compiler_crashers_2_fixed/35129b57d7eb80f4.swift b/validation-test/compiler_crashers_2_fixed/35129b57d7eb80f4.swift
new file mode 100644
index 0000000000000..043be0648f71a
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/35129b57d7eb80f4.swift
@@ -0,0 +1,3 @@
+// {"signature":"(anonymous namespace)::ExprWalker::rewriteTarget(swift::constraints::SyntacticElementTarget)"}
+// RUN: not %target-swift-frontend -typecheck %s
+{ Sendable(Sendable<<a
diff --git a/validation-test/compiler_crashers_2_fixed/3badfb288fdf42f4.swift b/validation-test/compiler_crashers_2_fixed/3badfb288fdf42f4.swift
new file mode 100644
index 0000000000000..d54b4d3b9f342
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/3badfb288fdf42f4.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::TypeSubstituter::transformDependentMemberType(swift::DependentMemberType*, swift::TypePosition)","signatureAssert":"Assertion failed: (Ptr && \"Cannot dereference a null Type!\"), function operator->"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Combine extension Publishers.Share where Upstream == {a <b , c > where Upstream == Publishers.FlatMap <b, c>
diff --git a/validation-test/compiler_crashers_2_fixed/3c95e32711989555.swift b/validation-test/compiler_crashers_2_fixed/3c95e32711989555.swift
new file mode 100644
index 0000000000000..c268126937154
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/3c95e32711989555.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::simplifyConformsToConstraint(swift::Type, swift::ProtocolDecl*, swift::constraints::ConstraintKind, swift::constraints::ConstraintLocatorBuilder, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>)","signatureAssert":"Assertion failed: (Index < Length && \"Invalid index!\"), function operator[]"}
+// RUN: not %target-swift-frontend -typecheck %s
+\_(error)
diff --git a/validation-test/compiler_crashers_2_fixed/3d5f395354b12a8.swift b/validation-test/compiler_crashers_2_fixed/3d5f395354b12a8.swift
new file mode 100644
index 0000000000000..57e6d0ec12bf1
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/3d5f395354b12a8.swift
@@ -0,0 +1,6 @@
+// {"signature":"bool llvm::function_ref<bool (swift::ProtocolConformanceRef)>::callback_fn<(anonymous namespace)::MismatchedIsolatedConformances>(long, swift::ProtocolConformanceRef)"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a {
+  {               print("\(\ " ")\n"
+  }
+  "\()\n"
diff --git a/validation-test/compiler_crashers_2_fixed/437e5d84c586a6e9.swift b/validation-test/compiler_crashers_2_fixed/437e5d84c586a6e9.swift
new file mode 100644
index 0000000000000..5abb09291daa4
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/437e5d84c586a6e9.swift
@@ -0,0 +1,3 @@
+// {"signature":"std::__1::optional<swift::Type> llvm::function_ref<std::__1::optional<swift::Type> (swift::TypeBase*)>::callback_fn<swift::constraints::FailureDiagnostic::resolveType(swift::Type, bool, bool) const::$_0>(long, swift::TypeBase*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+Array(repeat a
diff --git a/validation-test/compiler_crashers_2_fixed/43bf2cb496111e.swift b/validation-test/compiler_crashers_2_fixed/43bf2cb496111e.swift
new file mode 100644
index 0000000000000..2df690c1519a7
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/43bf2cb496111e.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::Lexer::formEscapedIdentifierToken(char const*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+``
diff --git a/validation-test/compiler_crashers_2_fixed/43f7a6012f6a255a.swift b/validation-test/compiler_crashers_2_fixed/43f7a6012f6a255a.swift
new file mode 100644
index 0000000000000..daa05bf65a9b1
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/43f7a6012f6a255a.swift
@@ -0,0 +1,7 @@
+// {"kind":"emit-ir","original":"493cc9db","signature":"(anonymous namespace)::TypeContextDescriptorBuilderBase<(anonymous namespace)::StructContextDescriptorBuilder, swift::StructDecl>::emit()"}
+// RUN: not %target-swift-frontend -emit-ir %s
+class a<b> {
+}
+@available(SwiftStdlib 6.2, *)
+struct c<let d: a<e>, e> {
+}
diff --git a/validation-test/compiler_crashers_2_fixed/441e44e28042d5a3.swift b/validation-test/compiler_crashers_2_fixed/441e44e28042d5a3.swift
new file mode 100644
index 0000000000000..5b6e0e7abafed
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/441e44e28042d5a3.swift
@@ -0,0 +1,3 @@
+// {"signature":"deriveBodyRawRepresentable_init(swift::AbstractFunctionDecl*, void*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+a enum a : Int { case = #/
diff --git a/validation-test/compiler_crashers_2_fixed/448bdb8b9df6dd2.swift b/validation-test/compiler_crashers_2_fixed/448bdb8b9df6dd2.swift
new file mode 100644
index 0000000000000..d975dbcedb5a0
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/448bdb8b9df6dd2.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::DeclRefTypeRepr::overwriteNameRef(swift::DeclNameRef)"}
+// RUN: not %target-swift-frontend -typecheck %s
+switch {                         case    init(
diff --git a/validation-test/compiler_crashers_2_fixed/4c7611b7d95a1fb.swift b/validation-test/compiler_crashers_2_fixed/4c7611b7d95a1fb.swift
new file mode 100644
index 0000000000000..cd3beac66652e
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/4c7611b7d95a1fb.swift
@@ -0,0 +1,3 @@
+// {"signature":"(anonymous namespace)::ConstraintWalker::walkToExprPost(swift::Expr*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+\.+=
diff --git a/validation-test/compiler_crashers_2_fixed/4c84d3d852cdd1d4.swift b/validation-test/compiler_crashers_2_fixed/4c84d3d852cdd1d4.swift
new file mode 100644
index 0000000000000..ecee8f6d52804
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/4c84d3d852cdd1d4.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::ProtocolConformanceRef::forAbstract(swift::Type, swift::ProtocolDecl*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+var sixDoubles
+    : Double "six has the value [\( ( sixDoubles \[]) }0 \0\0 \0 \sixDoubles)"
diff --git a/validation-test/compiler_crashers_2_fixed/4d5c64ab845e174f.swift b/validation-test/compiler_crashers_2_fixed/4d5c64ab845e174f.swift
new file mode 100644
index 0000000000000..6a221b919c073
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/4d5c64ab845e174f.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::rewriting::RewriteSystem::computeCandidateConformancePaths(swift::rewriting::PropertyMap const&, llvm::MapVector<unsigned int, std::__1::vector<llvm::SmallVector<unsigned int, 2u>, std::__1::allocator<llvm::SmallVector<unsigned int, 2u>>>, llvm::DenseMap<unsigned int, unsigned int, llvm::DenseMapInfo<unsigned int, void>, llvm::detail::DenseMapPair<unsigned int, unsigned int>>, llvm::SmallVector<std::__1::pair<unsigned int, std::__1::vector<llvm::SmallVector<unsigned int, 2u>, std::__1::allocator<llvm::SmallVector<unsigned int, 2u>>>>, 0u>>&) const::$_0::operator()(unsigned int) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a { associatedtype b associatedtype c : a where c.c.c == Self, c.c.b== Self!
diff --git a/validation-test/compiler_crashers_2_fixed/4e0ec9b1a746e17.swift b/validation-test/compiler_crashers_2_fixed/4e0ec9b1a746e17.swift
new file mode 100644
index 0000000000000..a76aaafbf5945
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/4e0ec9b1a746e17.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::constraints::ConstraintSystem::recordOpenedTypes(swift::constraints::ConstraintLocatorBuilder, llvm::SmallVectorImpl<std::__1::pair<swift::GenericTypeParamType*, swift::TypeVariableType*>>&, bool)"}
+// RUN: not %target-swift-frontend -typecheck %s
+a<b> class a func a < c class b < d
diff --git a/validation-test/compiler_crashers_2_fixed/4e921915ae337fb5.swift b/validation-test/compiler_crashers_2_fixed/4e921915ae337fb5.swift
new file mode 100644
index 0000000000000..f223e88995d46
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/4e921915ae337fb5.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::ConditionalRequirementsRequest::evaluate(swift::Evaluator&, swift::NormalProtocolConformance*) const","signatureAssert":"Assertion failed: (typeSig.getCanonicalSignature().getGenericParams() == extensionSig.getCanonicalSignature().getGenericParams()), function evaluate"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a typealias b<c> = () extension b : a
diff --git a/validation-test/compiler_crashers_2_fixed/511f277d722d94a4.swift b/validation-test/compiler_crashers_2_fixed/511f277d722d94a4.swift
new file mode 100644
index 0000000000000..8d52b0c6b8ed3
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/511f277d722d94a4.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"098f0ede","signature":"swift::constraints::ConstraintSystem::getMemberReferenceTypeFromOpenedType(swift::Type, swift::Type, swift::ValueDecl*, swift::constraints::ConstraintLocator*, bool, bool)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not %target-swift-frontend -typecheck %s
+enum a<b> {
+  c = d  macro d()
+}
diff --git a/validation-test/compiler_crashers_2_fixed/548b48b935d4153a.swift b/validation-test/compiler_crashers_2_fixed/548b48b935d4153a.swift
new file mode 100644
index 0000000000000..cf72a8ae48cee
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/548b48b935d4153a.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::NominalType::get(swift::NominalTypeDecl*, swift::Type, swift::ASTContext const&)","signatureAssert":"Assertion failed: ((!Parent || Parent->is<NominalType>() || Parent->is<BoundGenericType>() || Parent->is<UnboundGenericType>()) && \"parent must be a nominal type\"), function get"}
+// RUN: not %target-swift-frontend -typecheck %s
+extension() {
+  struct a extension a
diff --git a/validation-test/compiler_crashers_2_fixed/548d48154de3e7d.swift b/validation-test/compiler_crashers_2_fixed/548d48154de3e7d.swift
new file mode 100644
index 0000000000000..1367e6e745965
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/548d48154de3e7d.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"f7872afc","signature":"swift::ParamDecl::setTypeCheckedDefaultExpr(swift::Expr*)","signatureAssert":"Assertion failed: (E || getDefaultArgumentKind() == DefaultArgumentKind::Inherited), function setTypeCheckedDefaultExpr"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a {
+  init<b>(b  = a(
diff --git a/validation-test/compiler_crashers_2_fixed/56edea24a97933f.swift b/validation-test/compiler_crashers_2_fixed/56edea24a97933f.swift
new file mode 100644
index 0000000000000..f64af92306ad6
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/56edea24a97933f.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::isRepresentableInObjC(swift::VarDecl const*, swift::ObjCReason)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+class a class b open extension b {
+  @objc c : a
diff --git a/validation-test/compiler_crashers_2_fixed/5716fcca10bf3ff7.swift b/validation-test/compiler_crashers_2_fixed/5716fcca10bf3ff7.swift
new file mode 100644
index 0000000000000..d75476d382f95
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/5716fcca10bf3ff7.swift
@@ -0,0 +1,6 @@
+// {"signature":"createImplicitConstructor(swift::NominalTypeDecl*, ImplicitConstructorKind, swift::ASTContext&)"}
+// RUN: not %target-swift-frontend -typecheck -swift-version 5 %s
+struct a @propertyWrapper struct b < c {
+  wrappedValue : c
+} @propertyWrapper struct d {
+  var wrappedValue @b var e : a @d var f
diff --git a/validation-test/compiler_crashers_2_fixed/59b42964e169b6fa.swift b/validation-test/compiler_crashers_2_fixed/59b42964e169b6fa.swift
new file mode 100644
index 0000000000000..9fb239872d3cb
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/59b42964e169b6fa.swift
@@ -0,0 +1,8 @@
+// {"signature":"swift::ProtocolConformanceRef::getProtocol() const"}
+// RUN: not %target-swift-frontend -typecheck %s
+   func a<each b {
+                   enum c {
+                    case struct  var d: e      struct e {
+                    g: c          }
+                     f {
+                    d.g == .struct 
diff --git a/validation-test/compiler_crashers_2_fixed/59ca7ce28cc05461.swift b/validation-test/compiler_crashers_2_fixed/59ca7ce28cc05461.swift
new file mode 100644
index 0000000000000..438ee2ae7131a
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/59ca7ce28cc05461.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","original":"1157c215","signature":"makeBinOp(swift::ASTContext&, swift::Expr*, swift::Expr*, swift::Expr*, swift::PrecedenceGroupDecl*, bool)"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  do 
+catch _ as a + {
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/5cc8bc3069f97958.swift b/validation-test/compiler_crashers_2_fixed/5cc8bc3069f97958.swift
new file mode 100644
index 0000000000000..996cb30444deb
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/5cc8bc3069f97958.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::TypeResolver::resolveImplicitlyUnwrappedOptionalType(swift::ImplicitlyUnwrappedOptionalTypeRepr*, swift::TypeResolutionOptions, bool)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  enum a: b! {
+  }
+  guard a else {
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/5ce9cd9830dc12a.swift b/validation-test/compiler_crashers_2_fixed/5ce9cd9830dc12a.swift
new file mode 100644
index 0000000000000..b8991061de652
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/5ce9cd9830dc12a.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::DeclAndTypePrinter::Implementation::visitVarDecl(swift::VarDecl*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+#init
diff --git a/validation-test/compiler_crashers_2_fixed/5f26ba86c56cc88.swift b/validation-test/compiler_crashers_2_fixed/5f26ba86c56cc88.swift
new file mode 100644
index 0000000000000..047b1ddc71b4c
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/5f26ba86c56cc88.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::getCalleeLocator(swift::constraints::ConstraintLocator*, bool, llvm::function_ref<swift::Type (swift::Expr*)>, llvm::function_ref<swift::Type (swift::Type)>, llvm::function_ref<std::__1::optional<swift::constraints::SelectedOverload> (swift::constraints::ConstraintLocator*)>)","signatureAssert":"Assertion failed: (Index < Length && \"Invalid index!\"), function operator[]"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a func b(c : [Int]) {
+  \ a(c.map{})
diff --git a/validation-test/compiler_crashers_2_fixed/624dafcf406667e8.swift b/validation-test/compiler_crashers_2_fixed/624dafcf406667e8.swift
new file mode 100644
index 0000000000000..7c68d69e696ba
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/624dafcf406667e8.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::SyntacticElementSolutionApplication::visitReturnStmt(swift::ReturnStmt*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+enum a func b(c : a) {
+let:
+  ()->Copyable = { c return
diff --git a/validation-test/compiler_crashers_2_fixed/64915463735bcf5b.swift b/validation-test/compiler_crashers_2_fixed/64915463735bcf5b.swift
new file mode 100644
index 0000000000000..67ffb2847a5c7
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/64915463735bcf5b.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::Evaluator::diagnoseCycle(swift::ActiveRequest const&)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: OS=macosx
+import Distributed typealias DefaultDistributedActorSystem = LocalTestingDistributedActorSystem distributed actor a{distributed...
diff --git a/validation-test/compiler_crashers_2_fixed/64bfdff1cfbfc74.swift b/validation-test/compiler_crashers_2_fixed/64bfdff1cfbfc74.swift
new file mode 100644
index 0000000000000..d63fab896975b
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/64bfdff1cfbfc74.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::simplifySameShapeConstraint(swift::Type, swift::Type, swift::optionset::OptionSet<swift::constraints::ConstraintSystem::TypeMatchFlags, unsigned int>, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a < each b {
+  c(d : repeat each b) {
+    c(preacidte : b) {
diff --git a/validation-test/compiler_crashers_2_fixed/662d871271047482.swift b/validation-test/compiler_crashers_2_fixed/662d871271047482.swift
new file mode 100644
index 0000000000000..5c8751cea11dd
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/662d871271047482.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"2e2249a5","signature":"swift::TypeBase::computeCanonicalType()","signatureAssert":"Assertion failed: (Result->isCanonical()), function computeCanonicalType"}
+// RUN: not %target-swift-frontend -typecheck %s
+typealias a<b> = (
+>extension a where b ==  {
+c
diff --git a/validation-test/compiler_crashers_2_fixed/666bd08556187ed3.swift b/validation-test/compiler_crashers_2_fixed/666bd08556187ed3.swift
new file mode 100644
index 0000000000000..d57b439a466d4
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/666bd08556187ed3.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::DeclChecker::visit(swift::Decl*)","signatureAssert":"Assertion failed: (false && \"Huh?\"), function isValidExtendedTypeForTupleExtension"}
+// RUN: not %target-swift-frontend -typecheck %s
+extension repeat (
diff --git a/validation-test/compiler_crashers_2_fixed/66e337320b1924c.swift b/validation-test/compiler_crashers_2_fixed/66e337320b1924c.swift
new file mode 100644
index 0000000000000..8e41eee816eda
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/66e337320b1924c.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::ProtocolRequiresClassRequest::diagnoseCycle(swift::DiagnosticEngine&) const","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct b let b c a = b protocol a : a
diff --git a/validation-test/compiler_crashers_2_fixed/6c90501cdf1449c2.swift b/validation-test/compiler_crashers_2_fixed/6c90501cdf1449c2.swift
new file mode 100644
index 0000000000000..dc356a10e5e93
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/6c90501cdf1449c2.swift
@@ -0,0 +1,3 @@
+// {"signature":"$s11swiftASTGen15parseSourceFile6buffer10moduleName8filename14declContextPtr4kindSVSo16BridgedStringRefV_A2ISvSgSo0n9GenerateddE4KindVtF"}
+// RUN: not %target-swift-frontend -typecheck %s
+"foobar""" a ab"""
diff --git a/validation-test/compiler_crashers_2_fixed/72eed0e8ff21c1a.swift b/validation-test/compiler_crashers_2_fixed/72eed0e8ff21c1a.swift
new file mode 100644
index 0000000000000..d5639d345e040
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/72eed0e8ff21c1a.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"isParamListRepresentableInLanguage(swift::AbstractFunctionDecl const*, swift::ParameterList const*, swift::ObjCReason)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+class a open extension a {
+  @objc b(_)
diff --git a/validation-test/compiler_crashers_2_fixed/75d8fd688b445bb.swift b/validation-test/compiler_crashers_2_fixed/75d8fd688b445bb.swift
new file mode 100644
index 0000000000000..22394f1471878
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/75d8fd688b445bb.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","original":"b7a10f72","signature":"(anonymous namespace)::Verifier::walkToExprPre(swift::Expr*)","signatureAssert":"Assertion failed: ((HadError || !isa<SourceFile *>(M) || cast<SourceFile *>(M)->ASTStage < SourceFile::TypeChecked) && \"OverloadedDeclRef\" \"in wrong phase\"), function walkToExprPre"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a(b : Int) {
+  _ = {
+    switch b {
+    case Optional<c>.d :
+      break
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/77b431f821682d0.swift b/validation-test/compiler_crashers_2_fixed/77b431f821682d0.swift
new file mode 100644
index 0000000000000..781d73937d186
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/77b431f821682d0.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::ProtocolConformanceRef::forEachMissingConformance(llvm::function_ref<bool (swift::BuiltinProtocolConformance*)>) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+.a == .!   == b /  c
diff --git a/validation-test/compiler_crashers_2_fixed/7aa9d3699dddb337.swift b/validation-test/compiler_crashers_2_fixed/7aa9d3699dddb337.swift
new file mode 100644
index 0000000000000..ef7871d8ee0f6
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/7aa9d3699dddb337.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::PatternTypeRequest::evaluate(swift::Evaluator&, swift::ContextualPattern) const","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+@objcMembers class a open extension a {
+  var b
diff --git a/validation-test/compiler_crashers_2_fixed/7cee1719e3503ef6.swift b/validation-test/compiler_crashers_2_fixed/7cee1719e3503ef6.swift
new file mode 100644
index 0000000000000..d154c4e46dbfc
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/7cee1719e3503ef6.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::GenericParamKey::findIndexIn(llvm::ArrayRef<swift::GenericTypeParamType*>) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+a[[[[ a a?[[a a?
diff --git a/validation-test/compiler_crashers_2_fixed/7d3e143ce48c791.swift b/validation-test/compiler_crashers_2_fixed/7d3e143ce48c791.swift
new file mode 100644
index 0000000000000..3f26f7f33addc
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/7d3e143ce48c791.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::NamingPatternRequest::evaluate(swift::Evaluator&, swift::VarDecl*) const","signatureAssert":"Assertion failed: (foundVarDecl && \"VarDecl not declared in its parent?\"), function evaluate"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  if
+  case.(let \ a) { a
diff --git a/validation-test/compiler_crashers_2_fixed/82fe033c6bdba61.swift b/validation-test/compiler_crashers_2_fixed/82fe033c6bdba61.swift
new file mode 100644
index 0000000000000..ea43bff0c0236
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/82fe033c6bdba61.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","signature":"swift::DerivedConformance::deriveDecodable(swift::ValueDecl*)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a {
+  var
+  b, c : Codable {
+    self
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/859bb4ca7e7e2bd.swift b/validation-test/compiler_crashers_2_fixed/859bb4ca7e7e2bd.swift
new file mode 100644
index 0000000000000..47959b56782dc
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/859bb4ca7e7e2bd.swift
@@ -0,0 +1,5 @@
+// {"kind":"emit-silgen","original":"6943e75f","signature":"swift::SILFunctionType::SILFunctionType(swift::GenericSignature, swift::SILExtInfo, swift::SILCoroutineKind, swift::ParameterConvention, llvm::ArrayRef<swift::SILParameterInfo>, llvm::ArrayRef<swift::SILYieldInfo>, llvm::ArrayRef<swift::SILResultInfo>, std::__1::optional<swift::SILResultInfo>, swift::SubstitutionMap, swift::SubstitutionMap, swift::ASTContext const&, swift::RecursiveTypeProperties, swift::ProtocolConformanceRef)"}
+// RUN: not %target-swift-frontend -emit-silgen %s
+func a<each b : BinaryInteger>(c : repeat each b) {
+  UInt32(repeat each c)
+}
diff --git a/validation-test/compiler_crashers_2_fixed/8879748097cd16db.swift b/validation-test/compiler_crashers_2_fixed/8879748097cd16db.swift
new file mode 100644
index 0000000000000..62fde04c4c388
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/8879748097cd16db.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","original":"16ab065c","signature":"swift::rewriting::RequirementMachine::checkCompletionResult(swift::rewriting::CompletionResult) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a: b
+  protocol b {
+    associatedtype c
+  }
+  protocol d: e,
+    f
+    protocol f: b where c: f
+      protocol e: a where c: e
diff --git a/validation-test/compiler_crashers_2_fixed/88ba80199b702649.swift b/validation-test/compiler_crashers_2_fixed/88ba80199b702649.swift
new file mode 100644
index 0000000000000..adffa65de7acc
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/88ba80199b702649.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ExprRewriter::finishApply(swift::ApplyExpr*, swift::Type, swift::constraints::ConstraintLocatorBuilder, swift::constraints::ConstraintLocatorBuilder)","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a(b : ()->Void c : _->Void) { withoutActuallyEscaping(b do : c
diff --git a/validation-test/compiler_crashers_2_fixed/88e136b5aa17e82f.swift b/validation-test/compiler_crashers_2_fixed/88e136b5aa17e82f.swift
new file mode 100644
index 0000000000000..62510db6f471b
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/88e136b5aa17e82f.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"3a2652c9","signature":"(anonymous namespace)::OpaqueUnderlyingTypeChecker::check()","signatureAssert":"Assertion failed: (!UniqueUnderlyingType.has_value() && \"resetting underlying type?!\"), function setUniqueUnderlyingTypeSubstitutions"}
+// RUN: not %target-swift-frontend -typecheck %s
+var a: some Any = 0.0 {
+  0
+}
diff --git a/validation-test/compiler_crashers_2_fixed/89acda2815351ec6.swift b/validation-test/compiler_crashers_2_fixed/89acda2815351ec6.swift
new file mode 100644
index 0000000000000..6516f97e03fd1
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/89acda2815351ec6.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ExprRewriter::coerceToType(swift::Expr*, swift::Type, swift::constraints::ConstraintLocatorBuilder)::$_3::operator()(swift::Type, swift::Type) const","signatureAssert":"Assertion failed: (restriction == ConversionRestrictionKind::DeepEquality), function operator()"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a(inout _ )
+var b = String
+a(b
diff --git a/validation-test/compiler_crashers_2_fixed/89b5f5bb4b65efe.swift b/validation-test/compiler_crashers_2_fixed/89b5f5bb4b65efe.swift
new file mode 100644
index 0000000000000..9f5b480b83146
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/89b5f5bb4b65efe.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"01146903","signature":"(anonymous namespace)::ConstraintWalker::walkToExprPost(swift::Expr*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+switch <#expression#> {
+case let .a -> b:
+  b
+}
diff --git a/validation-test/compiler_crashers_2_fixed/89bcf379b8d4d092.swift b/validation-test/compiler_crashers_2_fixed/89bcf379b8d4d092.swift
new file mode 100644
index 0000000000000..e4e4a3fc6c6e3
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/89bcf379b8d4d092.swift
@@ -0,0 +1,6 @@
+// {"signature":"swift::FunctionType::get(llvm::ArrayRef<swift::AnyFunctionType::Param>, swift::Type, std::__1::optional<swift::ASTExtInfo>)"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a < b : FixedWidthInteger extension a : Sequence {
+  c {
+    { for
+        d self { b(truncatingIfNeeded : d
diff --git a/validation-test/compiler_crashers_2_fixed/8a6431938ab864b3.swift b/validation-test/compiler_crashers_2_fixed/8a6431938ab864b3.swift
new file mode 100644
index 0000000000000..e6e63fd903058
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/8a6431938ab864b3.swift
@@ -0,0 +1,5 @@
+// {"signature":"swift::rewriting::RequirementMachine::checkCompletionResult(swift::rewriting::CompletionResult) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a : b protocol b{associatedtype c} protocol d : e,
+                                                         f protocol e
+    : g where c : e protocol g : b protocol f : a where c : f
diff --git a/validation-test/compiler_crashers_2_fixed/8a65840ca91fedd9.swift b/validation-test/compiler_crashers_2_fixed/8a65840ca91fedd9.swift
new file mode 100644
index 0000000000000..ebf6724ba0f30
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/8a65840ca91fedd9.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::TypeChecker::typesSatisfyConstraint(swift::Type, swift::Type, bool, swift::constraints::ConstraintKind, swift::DeclContext*, bool*)","signatureAssert":"Assertion failed: (!type1->getRecursiveProperties().isSolverAllocated() && !type2->getRecursiveProperties().isSolverAllocated() && \"Cannot escape solver-allocated types into a nested ConstraintSystem\"), function typesSatisfyConstraint"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a<each b>(c : repeat each b) { repeat !(d c
diff --git a/validation-test/compiler_crashers_2_fixed/8c2d6198e18a56a.swift b/validation-test/compiler_crashers_2_fixed/8c2d6198e18a56a.swift
new file mode 100644
index 0000000000000..f2a531038c186
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/8c2d6198e18a56a.swift
@@ -0,0 +1,4 @@
+// {"signature":"$s11swiftASTGen15parseSourceFile6buffer10moduleName8filename14declContextPtr4kindSVSo16BridgedStringRefV_A2ISvSgSo0n9GenerateddE4KindVtF"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: swift_swift_parser
+#sourceLocation """\("
diff --git a/validation-test/compiler_crashers_2_fixed/8d73bb4170a0c447.swift b/validation-test/compiler_crashers_2_fixed/8d73bb4170a0c447.swift
new file mode 100644
index 0000000000000..7a79523337172
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/8d73bb4170a0c447.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::ParamDecl::setTypeCheckedDefaultExpr(swift::Expr*)","signatureAssert":"Assertion failed: (E || getDefaultArgumentKind() == DefaultArgumentKind::Inherited), function setTypeCheckedDefaultExpr"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a<b>(b= a(
diff --git a/validation-test/compiler_crashers_2_fixed/90773c979d435f7.swift b/validation-test/compiler_crashers_2_fixed/90773c979d435f7.swift
new file mode 100644
index 0000000000000..dccfdaecd70c6
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/90773c979d435f7.swift
@@ -0,0 +1,8 @@
+// {"signature":"swift::isOverrideBasedOnType(swift::ValueDecl const*, swift::Type, swift::ValueDecl const*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a < b {
+  protocol c { associatedtype d init(e : d
+  }
+  class f {
+    init(e : Int) {
+      class 4 : f, c { init(e : d
diff --git a/validation-test/compiler_crashers_2_fixed/93eaba9fd0e76cdf.swift b/validation-test/compiler_crashers_2_fixed/93eaba9fd0e76cdf.swift
new file mode 100644
index 0000000000000..97cda574e4c59
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/93eaba9fd0e76cdf.swift
@@ -0,0 +1,3 @@
+// {"signature":"diagnoseDictionaryLiteralDuplicateKeyEntries(swift::Expr const*, swift::DeclContext const*)::DiagnoseWalker::walkToExprPre(swift::Expr*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+[ 1.01: "" 1.01: ""
diff --git a/validation-test/compiler_crashers_2_fixed/966aa8f86a7565d3.swift b/validation-test/compiler_crashers_2_fixed/966aa8f86a7565d3.swift
new file mode 100644
index 0000000000000..e14eabc6f6918
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/966aa8f86a7565d3.swift
@@ -0,0 +1,12 @@
+// {"kind":"typecheck","original":"71a26232","signature":"swift::Decl::getDescriptiveKind() const"}
+// RUN: not %target-swift-frontend -typecheck %s
+typealias a = ()
+extension a {
+  func
+    < (b: Self, c: Self)
+  {
+    for (d, e) in repeat (each b    each c) {
+      d < &e
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/983a37d706b4923e.swift b/validation-test/compiler_crashers_2_fixed/983a37d706b4923e.swift
new file mode 100644
index 0000000000000..ef84dbe79382f
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/983a37d706b4923e.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::TypeBase::getNominalParent()","signatureAssert":"Assertion failed: (isa<To>(Val) && \"cast<Ty>() argument of incompatible type!\"), function cast"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a {
+  typealias b<c> = () extension b
diff --git a/validation-test/compiler_crashers_2_fixed/9adf18151655a6ae.swift b/validation-test/compiler_crashers_2_fixed/9adf18151655a6ae.swift
new file mode 100644
index 0000000000000..1a0b27892b349
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/9adf18151655a6ae.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::DeclChecker::visit(swift::Decl*)","signatureAssert":"Assertion failed: (false && \"Huh?\"), function isValidExtendedTypeForTupleExtension"}
+// RUN: not %target-swift-frontend -typecheck %s
+typealias a<b> = (repeat b)protocol c extension a : c
diff --git a/validation-test/compiler_crashers_2_fixed/9ae5dcaffa1a80.swift b/validation-test/compiler_crashers_2_fixed/9ae5dcaffa1a80.swift
new file mode 100644
index 0000000000000..5c064b5476976
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/9ae5dcaffa1a80.swift
@@ -0,0 +1,6 @@
+// {"signature":"void (anonymous namespace)::StmtChecker::checkSiblingCaseStmts<swift::CaseStmt* const*>(swift::CaseStmt* const*, swift::CaseStmt* const*, swift::CaseParentKind, bool&, swift::Type)"}
+// RUN: not %target-swift-frontend -typecheck %s
+enum a func b(c : a) -> Int {
+  switch
+    c {
+    case (let \d)d
diff --git a/validation-test/compiler_crashers_2_fixed/9b91d843ce95d4f.swift b/validation-test/compiler_crashers_2_fixed/9b91d843ce95d4f.swift
new file mode 100644
index 0000000000000..1f9b51a2ab0e5
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/9b91d843ce95d4f.swift
@@ -0,0 +1,5 @@
+// {"signature":"swift::ide::printTypeUSR(swift::Type, llvm::raw_ostream&)"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a {
+  class b < c class e : a<> {
+    d = b
diff --git a/validation-test/compiler_crashers_2_fixed/9bcd81ba2b5cf37e.swift b/validation-test/compiler_crashers_2_fixed/9bcd81ba2b5cf37e.swift
new file mode 100644
index 0000000000000..82967a497f386
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/9bcd81ba2b5cf37e.swift
@@ -0,0 +1,10 @@
+// {"kind":"typecheck","original":"0a6d4af4","signature":"swift::AvailabilityContext::Storage::get(swift::AvailabilityRange const&, bool, llvm::ArrayRef<swift::AvailabilityContext::DomainInfo>, swift::ASTContext const&)"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a {
+  associatedtype b
+  func append < c : a where b == c>()
+  struct d : a {
+    typealias b = Int
+    func append()
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/9cb8f8475c5d414b.swift b/validation-test/compiler_crashers_2_fixed/9cb8f8475c5d414b.swift
new file mode 100644
index 0000000000000..6445cc2da0760
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/9cb8f8475c5d414b.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ExprWalker::rewriteTarget(swift::constraints::SyntacticElementTarget)"}
+// RUN: not %target-swift-frontend -typecheck %s
+a < {
+  AnyObject ( <b)
+}
diff --git a/validation-test/compiler_crashers_2_fixed/9f5254267aa3a27c.swift b/validation-test/compiler_crashers_2_fixed/9f5254267aa3a27c.swift
new file mode 100644
index 0000000000000..a9e7408c3e200
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/9f5254267aa3a27c.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::Pattern::getType() const"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  let $a:
diff --git a/validation-test/compiler_crashers_2_fixed/a5fbf4336df96867.swift b/validation-test/compiler_crashers_2_fixed/a5fbf4336df96867.swift
new file mode 100644
index 0000000000000..c3d405f027ef8
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/a5fbf4336df96867.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::TypeTransform<swift::Type::transformRec(llvm::function_ref<std::__1::optional<swift::Type> (swift::TypeBase*)>) const::Transform>::doIt(swift::Type, swift::TypePosition)"}
+// RUN: not %target-swift-frontend -typecheck %s
+@dynamicMemberLookup struct S<T> {
+  init(_: () -> T) {}
+  subscript<U>(dynamicMember d: WritableKeyPath<T, U>) -> S<U> {}
+}
+let x = S { x.e }
diff --git a/validation-test/compiler_crashers_2_fixed/a81ff5cc2d29ef15.swift b/validation-test/compiler_crashers_2_fixed/a81ff5cc2d29ef15.swift
new file mode 100644
index 0000000000000..8f9d57cb13841
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/a81ff5cc2d29ef15.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::IsStaticRequest::evaluate(swift::Evaluator&, swift::FuncDecl*) const","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+@objcMembers class a open extension a {
+  ...
diff --git a/validation-test/compiler_crashers_2_fixed/a8575b8261697c42.swift b/validation-test/compiler_crashers_2_fixed/a8575b8261697c42.swift
new file mode 100644
index 0000000000000..2de09f6c8b30d
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/a8575b8261697c42.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","original":"9e6249db","signature":"(anonymous namespace)::ConstraintGenerator::visitApplyExpr(swift::ApplyExpr*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+(a as Sequence).Element {
+}
diff --git a/validation-test/compiler_crashers_2_fixed/a9f541ae5c40ef35.swift b/validation-test/compiler_crashers_2_fixed/a9f541ae5c40ef35.swift
new file mode 100644
index 0000000000000..e74acdceb6a01
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/a9f541ae5c40ef35.swift
@@ -0,0 +1,3 @@
+// {"signature":"(anonymous namespace)::ABIDependencyEvaluator::computeABIDependenciesForModule(swift::ModuleDecl*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a { init? { init!
diff --git a/validation-test/compiler_crashers_2_fixed/aa9ebb248dabc27b.swift b/validation-test/compiler_crashers_2_fixed/aa9ebb248dabc27b.swift
new file mode 100644
index 0000000000000..1a4544780c063
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/aa9ebb248dabc27b.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::ConformanceChecker::resolveWitnessViaDerivation(swift::ValueDecl*)","signatureAssert":"Assertion failed: (Conformance->getWitnessUncached(requirement).getDecl() == match.Witness && \"Deduced different witnesses?\"), function recordWitness"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a : Codable {
+  b = a(
diff --git a/validation-test/compiler_crashers_2_fixed/ab146c5c26ca113.swift b/validation-test/compiler_crashers_2_fixed/ab146c5c26ca113.swift
new file mode 100644
index 0000000000000..5f453049fa2ea
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/ab146c5c26ca113.swift
@@ -0,0 +1,3 @@
+// {"signature":"getIsolationFromAttributes(swift::Decl const*, bool, bool)"}
+// RUN: not %target-swift-frontend -typecheck %s
+isolated let a
diff --git a/validation-test/compiler_crashers_2_fixed/ac7123f2338b128.swift b/validation-test/compiler_crashers_2_fixed/ac7123f2338b128.swift
new file mode 100644
index 0000000000000..584bfa97f3600
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/ac7123f2338b128.swift
@@ -0,0 +1,13 @@
+// {"signature":"swift::TypeChecker::typeCheckTarget(swift::constraints::SyntacticElementTarget&, swift::optionset::OptionSet<swift::TypeCheckExprFlags, unsigned int>, swift::DiagnosticTransaction*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+enum a
+  protocol b {
+    associatedtype c
+    associatedtype d
+    init(
+      e
+      : c -> d
+    struct f
+    : b {
+g: d init(e
+        : a -> _
diff --git a/validation-test/compiler_crashers_2_fixed/ad9313b914fb2.swift b/validation-test/compiler_crashers_2_fixed/ad9313b914fb2.swift
new file mode 100644
index 0000000000000..6c56558edbc85
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/ad9313b914fb2.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::Evaluator::diagnoseCycle(swift::ActiveRequest const&)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a
+  let _ b = a
+  class b : b.c
diff --git a/validation-test/compiler_crashers_2_fixed/af7dc08992398ff.swift b/validation-test/compiler_crashers_2_fixed/af7dc08992398ff.swift
new file mode 100644
index 0000000000000..960aae1eee7f9
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/af7dc08992398ff.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"constrainDomainInfos(llvm::SmallVectorImpl<swift::AvailabilityContext::DomainInfo>&, llvm::ArrayRef<swift::AvailabilityContext::DomainInfo>)","signatureAssert":"Assertion failed: (!isConstrained), function constrainDomainInfos"}
+// RUN: not %target-swift-frontend -typecheck %s
+@available(*, unavailable) @available(_PackageDescription 3) func a {
+  @available(_PackageDescription 5) func b
diff --git a/validation-test/compiler_crashers_2_fixed/b31917ad9b8e4fe4.swift b/validation-test/compiler_crashers_2_fixed/b31917ad9b8e4fe4.swift
new file mode 100644
index 0000000000000..bc8b7f7579bd1
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/b31917ad9b8e4fe4.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"0df5dc82","signature":"swift::constraints::ConstraintSystem::typeVarOccursInType(swift::TypeVariableType*, swift::Type, bool*)","signatureAssert":"Assertion failed: ((!typeVariables.empty() || hasError()) && \"Did not find type variables!\"), function getTypeVariables"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a<each b {
+  typealias d<c> = (
+  >  func  1 {
+    typealias e = f
+    e
+    typealias e = d
diff --git a/validation-test/compiler_crashers_2_fixed/b33dbab8ed3643.swift b/validation-test/compiler_crashers_2_fixed/b33dbab8ed3643.swift
new file mode 100644
index 0000000000000..12dbbbbe7d357
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/b33dbab8ed3643.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::TypeBase::computeCanonicalType()"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a (Int -> Int = { $0 func b( () = {}? ) func b {
+    / 1
diff --git a/validation-test/compiler_crashers_2_fixed/b4746f0a8b4efd96.swift b/validation-test/compiler_crashers_2_fixed/b4746f0a8b4efd96.swift
new file mode 100644
index 0000000000000..7b6ebf63339da
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/b4746f0a8b4efd96.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::DeclChecker::visit(swift::Decl*)","signatureAssert":"Assertion failed: (false && \"Huh?\"), function isValidExtendedTypeForTupleExtension"}
+// RUN: not %target-swift-frontend -typecheck %s
+extension(a[ 0.0 b
diff --git a/validation-test/compiler_crashers_2_fixed/b93e9e54c72f13c9.swift b/validation-test/compiler_crashers_2_fixed/b93e9e54c72f13c9.swift
new file mode 100644
index 0000000000000..79a791d6d04f8
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/b93e9e54c72f13c9.swift
@@ -0,0 +1,6 @@
+// {"signature":"swift::rewriting::RewriteSystem::processTypeDifference(swift::rewriting::TypeDifference const&, unsigned int, unsigned int, swift::rewriting::RewritePath const&)"}
+// RUN: not %target-swift-frontend -typecheck %s
+class a < b class c<b, h> : a<(b, h)> protocol d {
+  associatedtype b : c<e, f> associatedtype e associatedtype f associatedtype b
+      : a<g>
+            associatedtype g where g == e
diff --git a/validation-test/compiler_crashers_2_fixed/b9c30d56ac83b29.swift b/validation-test/compiler_crashers_2_fixed/b9c30d56ac83b29.swift
new file mode 100644
index 0000000000000..203e594b118ab
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/b9c30d56ac83b29.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"1bb3e6fd","signature":"swift::constraints::ConstraintSystem::applySolution(swift::constraints::Solution&, swift::constraints::SyntacticElementTarget)","signatureAssert":"Assertion failed: (isValidType(type) && \"type binding has invalid type\"), function applySolution"}
+// RUN: not %target-swift-frontend -typecheck %s
+@propertyWrapper struct a<b {
+  wrappedValue: b
+}
+func c(@a _ )
diff --git a/validation-test/compiler_crashers_2_fixed/bafa48a4eecbfb62.swift b/validation-test/compiler_crashers_2_fixed/bafa48a4eecbfb62.swift
new file mode 100644
index 0000000000000..38aef2d70c875
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/bafa48a4eecbfb62.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"diagnoseUnknownType(swift::TypeResolution const&, swift::Type, swift::SourceRange, swift::DeclRefTypeRepr*, swift::optionset::OptionSet<swift::NameLookupFlags, unsigned int>)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+class b open extension b {
+  @objc c : a
diff --git a/validation-test/compiler_crashers_2_fixed/bf67776f769fa0f1.swift b/validation-test/compiler_crashers_2_fixed/bf67776f769fa0f1.swift
new file mode 100644
index 0000000000000..ad88a55f6ba3d
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/bf67776f769fa0f1.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::TypeResolver::resolveType(swift::TypeRepr*, swift::TypeResolutionOptions)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+class a open extension a {
+  @objc b : _
diff --git a/validation-test/compiler_crashers_2_fixed/c232a2df5b6fffd.swift b/validation-test/compiler_crashers_2_fixed/c232a2df5b6fffd.swift
new file mode 100644
index 0000000000000..0290d463b9a7b
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/c232a2df5b6fffd.swift
@@ -0,0 +1,8 @@
+// {"signature":"swift::constraints::ConstraintSystem::getTypeOfMemberReference(swift::Type, swift::ValueDecl*, swift::DeclContext*, bool, swift::FunctionRefInfo, swift::constraints::ConstraintLocator*, llvm::SmallVectorImpl<std::__1::pair<swift::GenericTypeParamType*, swift::TypeVariableType*>>*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a < let b > {
+  func
+  < (c : Self) {
+    c.b
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/c3a89a7cea373695.swift b/validation-test/compiler_crashers_2_fixed/c3a89a7cea373695.swift
new file mode 100644
index 0000000000000..5732b76bdd3c7
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/c3a89a7cea373695.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::doesMemberRefApplyCurriedSelf(swift::Type, swift::ValueDecl const*)","signatureAssert":"Assertion failed: (decl->getDeclContext()->isTypeContext() && \"Expected a member reference\"), function doesMemberRefApplyCurriedSelf"}
+// RUN: not %target-swift-frontend -typecheck %s
+Swift < .Int
diff --git a/validation-test/compiler_crashers_2_fixed/c5955772856ea0fa.swift b/validation-test/compiler_crashers_2_fixed/c5955772856ea0fa.swift
new file mode 100644
index 0000000000000..89e02af41e4c2
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/c5955772856ea0fa.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::Constraint::create(swift::constraints::ConstraintSystem&, swift::constraints::ConstraintKind, swift::Type, swift::Type, swift::constraints::ConstraintLocator*, llvm::ArrayRef<swift::TypeVariableType*>)","signatureAssert":"Assertion failed: ((kind != ConstraintKind::ConformsTo && kind != ConstraintKind::NonisolatedConformsTo && kind != ConstraintKind::TransitivelyConformsTo) || second->isExistentialType()), function create"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a let : a.Type.Type = b->c
diff --git a/validation-test/compiler_crashers_2_fixed/c8563a4a60b27cf3.swift b/validation-test/compiler_crashers_2_fixed/c8563a4a60b27cf3.swift
new file mode 100644
index 0000000000000..97970c53ae7f2
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/c8563a4a60b27cf3.swift
@@ -0,0 +1,7 @@
+// {"signature":"swift::CanTypeVisitor<swift::TypeMatcher<desugarSameTypeRequirement(swift::Requirement, swift::SourceLoc, llvm::SmallVectorImpl<swift::Requirement>&, llvm::SmallVectorImpl<swift::InverseRequirement>&, llvm::SmallVectorImpl<swift::rewriting::RequirementError>&)::Matcher>::MatchVisitor, bool, swift::Type, swift::Type>::visit(swift::CanType, swift::Type, swift::Type)"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a {
+  associatedtype b associatedtype c associatedtype d func e(b, c) -> d
+}
+struct f < j, g : a where h == g.c struct i<j> : a {
+  e(j, _) extension f where g == i<j>
diff --git a/validation-test/compiler_crashers_2_fixed/cad1ff6235b5b3d.swift b/validation-test/compiler_crashers_2_fixed/cad1ff6235b5b3d.swift
new file mode 100644
index 0000000000000..66d43cda3d2e4
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/cad1ff6235b5b3d.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::isArgumentGenericFunction(swift::Type, swift::Expr*)","signatureAssert":"Assertion failed: (!getFixedType(tyvar)), function getUnboundBindOverloadDisjunction"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  print($0) $00 + 0. / 1
diff --git a/validation-test/compiler_crashers_2_fixed/cccd6394993ea4a2.swift b/validation-test/compiler_crashers_2_fixed/cccd6394993ea4a2.swift
new file mode 100644
index 0000000000000..8e5de4b4d3764
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/cccd6394993ea4a2.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::ErrorType::get(swift::Type)"}
+// RUN: not %target-swift-frontend -typecheck %s
+@convention(c) _->Int
diff --git a/validation-test/compiler_crashers_2_fixed/ce57354c94ae5aad.swift b/validation-test/compiler_crashers_2_fixed/ce57354c94ae5aad.swift
new file mode 100644
index 0000000000000..2da7a28802a31
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/ce57354c94ae5aad.swift
@@ -0,0 +1,10 @@
+// {"kind":"emit-silgen","signature":"swift::CanTypeVisitor<swift::Lowering::TypeConverter::computeLoweredRValueType(swift::TypeExpansionContext, swift::Lowering::AbstractionPattern, swift::CanType)::LoweredRValueTypeVisitor, swift::CanType>::visit(swift::CanType)"}
+// RUN: not %target-swift-frontend -emit-silgen %s
+protocol a {
+  func b() -> _
+}
+do {
+  func c(d : a) {
+    let e = d.b
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/d03a7ba9ca6274b0.swift b/validation-test/compiler_crashers_2_fixed/d03a7ba9ca6274b0.swift
new file mode 100644
index 0000000000000..3a0f439939d95
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/d03a7ba9ca6274b0.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::ParamSpecifierRequest::evaluate(swift::Evaluator&, swift::ParamDecl*) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a([0])
diff --git a/validation-test/compiler_crashers_2_fixed/d14a9abe37cc3bca.swift b/validation-test/compiler_crashers_2_fixed/d14a9abe37cc3bca.swift
new file mode 100644
index 0000000000000..97ea4b9192190
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/d14a9abe37cc3bca.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::SolverTrail::~SolverTrail()","signatureAssert":"Assertion failed: (Changes.empty() && \"Trail corrupted\"), function ~SolverTrail"}
+// RUN: not %target-swift-frontend -typecheck %s
+enum a< b { case c(}
+         func d< b >(b->a< b >) d(a< e >.c let a
diff --git a/validation-test/compiler_crashers_2_fixed/d48def542970cfa.swift b/validation-test/compiler_crashers_2_fixed/d48def542970cfa.swift
new file mode 100644
index 0000000000000..33d9b14c41143
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/d48def542970cfa.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::rewriting::performConcreteContraction(llvm::ArrayRef<swift::StructuralRequirement>, llvm::SmallVectorImpl<swift::StructuralRequirement>&, llvm::SmallVectorImpl<swift::rewriting::RequirementError>&, bool)"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a < each b, each c where(repeat(each c each b)) : {
+  typealias d<each b> = () func e where d<repeat each b> ==
diff --git a/validation-test/compiler_crashers_2_fixed/d4a53522d2dce157.swift b/validation-test/compiler_crashers_2_fixed/d4a53522d2dce157.swift
new file mode 100644
index 0000000000000..f4e666c6147dd
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/d4a53522d2dce157.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","original":"e0be092d","signature":"swift::constraints::IgnoreAssignmentDestinationType::diagnoseForAmbiguity(llvm::ArrayRef<std::__1::pair<swift::constraints::Solution const*, swift::constraints::ConstraintFix const*>>) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+stride = (a:2).0
diff --git a/validation-test/compiler_crashers_2_fixed/d5eedcc26a9c0a1f.swift b/validation-test/compiler_crashers_2_fixed/d5eedcc26a9c0a1f.swift
new file mode 100644
index 0000000000000..1ad323fd2c252
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/d5eedcc26a9c0a1f.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","signature":"swift::TypeBase::getReducedShape()","signatureAssert":"Assertion failed: (!isTypeVariableOrMember()), function getReducedShape"}
+// RUN: not %target-swift-frontend -typecheck %s
+typealias a <b> = ()
+extension a {
+c {
+  d
+}
+d
diff --git a/validation-test/compiler_crashers_2_fixed/d815492a6398a52.swift b/validation-test/compiler_crashers_2_fixed/d815492a6398a52.swift
new file mode 100644
index 0000000000000..babb435e2fe5e
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/d815492a6398a52.swift
@@ -0,0 +1,15 @@
+// {"kind":"typecheck","original":"cc407c71","signature":"(anonymous namespace)::TypeSubstituter::transformOpaqueTypeArchetypeType(swift::OpaqueTypeArchetypeType*, swift::TypePosition)","stackOverflow":true}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a
+  @resultBuilder struct b {
+    static  buildBlock<each c>(repeat each c) -> d<repeat each c>
+  }
+  struct d<each e
+    struct f<e {
+      @b  content: e
+    }
+    extension f: a
+      var body: some a {
+        f {
+          f {
+            body
diff --git a/validation-test/compiler_crashers_2_fixed/d84cbb5089113ba.swift b/validation-test/compiler_crashers_2_fixed/d84cbb5089113ba.swift
new file mode 100644
index 0000000000000..3f401735aa658
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/d84cbb5089113ba.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::constraints::Solution::simplifyType(swift::Type, bool) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+for (a(b, d)) in [(repeat .c)].enumerated(<#expression#>) {
+}
diff --git a/validation-test/compiler_crashers_2_fixed/d885506018b583.swift b/validation-test/compiler_crashers_2_fixed/d885506018b583.swift
new file mode 100644
index 0000000000000..1f29e8a723bae
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/d885506018b583.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::AvailabilityContext::Storage::get(swift::AvailabilityRange const&, bool, llvm::ArrayRef<swift::AvailabilityContext::DomainInfo>, swift::ASTContext const&)"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a extension a where b == Self{c : } typealias b : Sequence
diff --git a/validation-test/compiler_crashers_2_fixed/da2c588d8b81b55b.swift b/validation-test/compiler_crashers_2_fixed/da2c588d8b81b55b.swift
new file mode 100644
index 0000000000000..26c7962002467
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/da2c588d8b81b55b.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","original":"a01bf256","signature":"swift::constraints::ConstraintSystem::applySolution(swift::constraints::Solution&, swift::constraints::SyntacticElementTarget)","signatureAssert":"Assertion failed: (isValidType(type) && \"type binding has invalid type\"), function applySolution"}
+// RUN: not %target-swift-frontend -typecheck %s
+enum b: Codable {
+  case a(_ = encode)
+}
diff --git a/validation-test/compiler_crashers_2_fixed/db15a23c5f8aeff.swift b/validation-test/compiler_crashers_2_fixed/db15a23c5f8aeff.swift
new file mode 100644
index 0000000000000..6d49f28bbc024
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/db15a23c5f8aeff.swift
@@ -0,0 +1,8 @@
+// {"kind":"typecheck","original":"36a5bbda","signature":"swift::SuperclassDeclRequest::diagnoseCycle(swift::DiagnosticEngine&) const","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  class a: a {
+  }
+  if a {
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/dc3a3e26162b43be.swift b/validation-test/compiler_crashers_2_fixed/dc3a3e26162b43be.swift
new file mode 100644
index 0000000000000..343d1067ecfe3
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/dc3a3e26162b43be.swift
@@ -0,0 +1,12 @@
+// {"signature":"(anonymous namespace)::SetExprTypes::walkToExprPost(swift::Expr*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+typealias a<b, c> = c
+struct d < each b {
+  typealias e< c > =
+  (repeat a< each b, c >)
+  typealias f< each c > = (repeat e< each c >
+  func 1 {
+    typealias g = h
+    (g<
+    i >
+    typealias g< each c > = f< repeat each c >
diff --git a/validation-test/compiler_crashers_2_fixed/dcd4ff250d0bde99.swift b/validation-test/compiler_crashers_2_fixed/dcd4ff250d0bde99.swift
new file mode 100644
index 0000000000000..9c6fb28ff0c27
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/dcd4ff250d0bde99.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::ValueDecl::isObjC() const","signatureAssert":"Assertion failed: (!LazySemanticInfo.isObjCComputed || LazySemanticInfo.isObjC == value), function setIsObjC"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+protocol a
+  @objc protocol b : c
+    @objc protocol d : b
+      @objc protocol c : d, a
diff --git a/validation-test/compiler_crashers_2_fixed/dfd09450bb7a1.swift b/validation-test/compiler_crashers_2_fixed/dfd09450bb7a1.swift
new file mode 100644
index 0000000000000..45248e6d5a0dd
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/dfd09450bb7a1.swift
@@ -0,0 +1,5 @@
+// {"signature":"swift::ProtocolConformanceRef::forAbstract(swift::Type, swift::ProtocolDecl*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+@resultBuilder struct a {
+  static buildBlock<b, c, d, e>(b, c, d, e) func f<h>(_ : Bool @a Bool->h) {                         f(true {
+    cond in var g : Int g 2 30\ g
diff --git a/validation-test/compiler_crashers_2_fixed/dfe03ade76b34fdb.swift b/validation-test/compiler_crashers_2_fixed/dfe03ade76b34fdb.swift
new file mode 100644
index 0000000000000..aecceeefe97af
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/dfe03ade76b34fdb.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::ASTContext::getSpecializedConformance(swift::Type, swift::NormalProtocolConformance*, swift::SubstitutionMap)","signatureAssert":"Assertion failed: (substitutions.getGenericSignature().getCanonicalSignature() == generic->getGenericSignature().getCanonicalSignature()), function getSpecializedConformance"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a{ < } protocol b { associatedtype c : a where d == Self }
+class e<f> : a where f : b, f.c == e
diff --git a/validation-test/compiler_crashers_2_fixed/e1f8b6a26663e9b5.swift b/validation-test/compiler_crashers_2_fixed/e1f8b6a26663e9b5.swift
new file mode 100644
index 0000000000000..5d2c71d8e5513
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/e1f8b6a26663e9b5.swift
@@ -0,0 +1,4 @@
+// {"signature":"swift::CanTypeVisitor<swift::TypeMatcher<(anonymous namespace)::AssociatedTypeInference::getPotentialTypeWitnessesByMatchingTypes(swift::ValueDecl*, swift::ValueDecl*)::MatchVisitor>::MatchVisitor, bool, swift::Type, swift::Type>::visit(swift::CanType, swift::Type, swift::Type)"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a { associatedtype b func c(_ : _ d: b }
+                         extension a { c(_ : _ d: b struct e : a
diff --git a/validation-test/compiler_crashers_2_fixed/e6a483a39992886f.swift b/validation-test/compiler_crashers_2_fixed/e6a483a39992886f.swift
new file mode 100644
index 0000000000000..da06b506ba23a
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/e6a483a39992886f.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::BuiltinTupleDecl::getTupleSelfType(swift::ExtensionDecl const*) const","signatureAssert":"Assertion failed: (genericParams->getParams().size() == 1), function getTupleSelfType"}
+// RUN: not %target-swift-frontend -typecheck %s
+typealias a<b, c> = () extension a
diff --git a/validation-test/compiler_crashers_2_fixed/e92d0acb419dec8e.swift b/validation-test/compiler_crashers_2_fixed/e92d0acb419dec8e.swift
new file mode 100644
index 0000000000000..561aee26d4f84
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/e92d0acb419dec8e.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"swift::GenericTypeParamType::GenericTypeParamType(swift::GenericTypeParamDecl*, swift::RecursiveTypeProperties)","signatureAssert":"Assertion failed: (param->getDepth() != GenericTypeParamDecl::InvalidDepth), function GenericTypeParamType"}
+// RUN: not %target-swift-frontend -typecheck %s
+typealias a = () extension a {
+  typealias b<c> = () extension b
diff --git a/validation-test/compiler_crashers_2_fixed/eb61865acc77c50.swift b/validation-test/compiler_crashers_2_fixed/eb61865acc77c50.swift
new file mode 100644
index 0000000000000..c7166a9122920
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/eb61865acc77c50.swift
@@ -0,0 +1,3 @@
+// {"signature":"(anonymous namespace)::SyntacticElementConstraintGenerator::visitBraceStmt(swift::BraceStmt*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+[ switch { case (let a)print(
diff --git a/validation-test/compiler_crashers_2_fixed/edb1d98948183f4c.swift b/validation-test/compiler_crashers_2_fixed/edb1d98948183f4c.swift
new file mode 100644
index 0000000000000..c8b280e9fe380
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/edb1d98948183f4c.swift
@@ -0,0 +1,10 @@
+// {"kind":"emit-silgen","signature":"emitRawApply(swift::Lowering::SILGenFunction&, swift::SILLocation, swift::Lowering::ManagedValue, swift::SubstitutionMap, llvm::ArrayRef<swift::Lowering::ManagedValue>, swift::CanTypeWrapper<swift::SILFunctionType>, swift::optionset::OptionSet<swift::ApplyFlags, unsigned char>, llvm::ArrayRef<swift::SILValue>, swift::SILValue, llvm::SmallVectorImpl<swift::SILValue>&, swift::Lowering::ExecutorBreadcrumb)"}
+// RUN: not %target-swift-frontend -emit-silgen %s
+protocol a {
+  func b() -> [(_) -> Self]
+}
+do {
+  func c(d : a) {
+    let e = d.b
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/ee519bcc17697e87.swift b/validation-test/compiler_crashers_2_fixed/ee519bcc17697e87.swift
new file mode 100644
index 0000000000000..f969b5d3054e1
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/ee519bcc17697e87.swift
@@ -0,0 +1,4 @@
+// {"signature":"(anonymous namespace)::ApplyClassifier::classifyApply(swift::ApplyExpr*, llvm::DenseSet<swift::Expr const*, llvm::DenseMapInfo<swift::Expr const*, void>>*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+let a = switch  \0 {
+case 0.0
diff --git a/validation-test/compiler_crashers_2_fixed/eeeed99e112fc53.swift b/validation-test/compiler_crashers_2_fixed/eeeed99e112fc53.swift
new file mode 100644
index 0000000000000..d00e4e36312cd
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/eeeed99e112fc53.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::Parser::parseTypeAttribute(llvm::PointerUnion<swift::CustomAttr*, swift::TypeAttribute*>&, swift::SourceLoc, swift::SourceLoc, swift::Parser::ParseTypeReason, bool)","signatureAssert":"Assertion failed: (Tok.is(K) && \"Consuming wrong token kind\"), function consumeToken"}
+// RUN: not %target-swift-frontend -typecheck %s
+@opened)
diff --git a/validation-test/compiler_crashers_2_fixed/eefe61949e1f5cfd.swift b/validation-test/compiler_crashers_2_fixed/eefe61949e1f5cfd.swift
new file mode 100644
index 0000000000000..8bf426b07ac04
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/eefe61949e1f5cfd.swift
@@ -0,0 +1,5 @@
+// {"signature":"$s11swiftASTGen15parseSourceFile6buffer10moduleName8filename14declContextPtr4kindSVSo16BridgedStringRefV_A2ISvSgSo0n9GenerateddE4KindVtF"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: swift_swift_parser
+{
+a: (a $
diff --git a/validation-test/compiler_crashers_2_fixed/empty_extension_print.swift b/validation-test/compiler_crashers_2_fixed/empty_extension_print.swift
new file mode 100644
index 0000000000000..74d18ab5d483a
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/empty_extension_print.swift
@@ -0,0 +1,2 @@
+// RUN: not %target-swift-frontend %s -dump-parse
+extension {}
diff --git a/validation-test/compiler_crashers_2_fixed/f6ae9d69266e6b1c.swift b/validation-test/compiler_crashers_2_fixed/f6ae9d69266e6b1c.swift
new file mode 100644
index 0000000000000..942b6d1817182
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/f6ae9d69266e6b1c.swift
@@ -0,0 +1,6 @@
+// {"kind":"typecheck","original":"0e81571d","signature":"swift::constraints::ConstraintSystem::applySolution(swift::constraints::Solution&, swift::constraints::SyntacticElementTarget)","signatureAssert":"Assertion failed: (isValidType(type) && \"type binding has invalid type\"), function applySolution"}
+// RUN: not %target-swift-frontend -typecheck %s
+subscript(a: _) -> <#type#> {
+  a
+  0
+}
diff --git a/validation-test/compiler_crashers_2_fixed/f7546097c158a148.swift b/validation-test/compiler_crashers_2_fixed/f7546097c158a148.swift
new file mode 100644
index 0000000000000..d81a98310cbf9
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/f7546097c158a148.swift
@@ -0,0 +1,4 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::ActorIsolationChecker::checkLocalCaptures(swift::AnyFunctionRef)","signatureAssert":"Assertion failed: (Captures.hasBeenComputed()), function getCaptureInfo"}
+// RUN: not %target-swift-frontend -typecheck %s
+struct a {
+  b : c =, d = {} protocol c
diff --git a/validation-test/compiler_crashers_2_fixed/f8296a9a293c6ae7.swift b/validation-test/compiler_crashers_2_fixed/f8296a9a293c6ae7.swift
new file mode 100644
index 0000000000000..2d875f2714084
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/f8296a9a293c6ae7.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::TypeResolver::resolveCompositionType(swift::CompositionTypeRepr*, swift::TypeResolutionOptions)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+class a open extension a {
+  @objc b : Int &
diff --git a/validation-test/compiler_crashers_2_fixed/faa012128bc0b7c7.swift b/validation-test/compiler_crashers_2_fixed/faa012128bc0b7c7.swift
new file mode 100644
index 0000000000000..42023d57ac6ae
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/faa012128bc0b7c7.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::TypeBase::getContextSubstitutions(swift::DeclContext const*, swift::GenericEnvironment*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+{                      $0?={
diff --git a/validation-test/compiler_crashers_2_fixed/fca26dd570bcdf1c.swift b/validation-test/compiler_crashers_2_fixed/fca26dd570bcdf1c.swift
new file mode 100644
index 0000000000000..ac6ae7e300572
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/fca26dd570bcdf1c.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"(anonymous namespace)::TypeResolver::resolveVarargType(swift::VarargTypeRepr*, swift::TypeResolutionOptions)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+class a open extension a {
+  @objc b : Int...
diff --git a/validation-test/compiler_crashers_2_fixed/fddb1549773c253.swift b/validation-test/compiler_crashers_2_fixed/fddb1549773c253.swift
new file mode 100644
index 0000000000000..0242b2657331a
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/fddb1549773c253.swift
@@ -0,0 +1,7 @@
+// {"kind":"typecheck","original":"5e6f691d","signature":"(anonymous namespace)::ConstraintGenerator::visitApplyExpr(swift::ApplyExpr*)"}
+// RUN: not %target-swift-frontend -typecheck %s
+protocol a {
+  associatedtype b
+  struct c<d, a {
+e {
+  d.b {
diff --git a/validation-test/compiler_crashers_2_fixed/fec3d092ae822aa6.swift b/validation-test/compiler_crashers_2_fixed/fec3d092ae822aa6.swift
new file mode 100644
index 0000000000000..ca91d84ec17ec
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/fec3d092ae822aa6.swift
@@ -0,0 +1,3 @@
+// {"signature":"swift::Parser::parseExprSequenceElement(swift::Diag<>, bool)"}
+// RUN: not %target-swift-frontend -typecheck %s
+any a <
diff --git a/validation-test/compiler_crashers_2_fixed/ff105cea796d442f.swift b/validation-test/compiler_crashers_2_fixed/ff105cea796d442f.swift
new file mode 100644
index 0000000000000..c47fa2fdd7fe8
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/ff105cea796d442f.swift
@@ -0,0 +1,5 @@
+// {"kind":"typecheck","signature":"swift::InFlightDiagnostic swift::diagnoseAttrWithRemovalFixIt<swift::Diag<>&>(swift::Decl const*, swift::DeclAttribute const*, swift::Diag<>&)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
+// RUN: not %target-swift-frontend -typecheck %s
+// REQUIRES: objc_interop
+class a open extension a {
+  @objc class b
diff --git a/validation-test/compiler_crashers_2_fixed/ff3414a48ee8f4cd.swift b/validation-test/compiler_crashers_2_fixed/ff3414a48ee8f4cd.swift
new file mode 100644
index 0000000000000..0d347114cd819
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/ff3414a48ee8f4cd.swift
@@ -0,0 +1,3 @@
+// {"kind":"typecheck","signature":"swift::constraints::Solution::simplifyType(swift::Type, bool) const"}
+// RUN: not %target-swift-frontend -typecheck %s
+[ ( repeat .a ), .b, (3 c
diff --git a/validation-test/compiler_crashers_2_fixed/issue-52031.swift b/validation-test/compiler_crashers_2_fixed/issue-52031.swift
index c8d96d07ce501..8cfb45ab08edf 100644
--- a/validation-test/compiler_crashers_2_fixed/issue-52031.swift
+++ b/validation-test/compiler_crashers_2_fixed/issue-52031.swift
@@ -13,8 +13,6 @@ extension S: P where N: P {
   static func f<X: P>(_ x: X) -> S<X.A> where A == X, X.A == N {
   // expected-error@-1 {{cannot build rewrite system for generic signature; rule length limit exceeded}}
   // expected-note@-2 {{τ_0_0.[P:A].[P:A].[P:A].[P:A].[P:A].[concrete: S<S<S<S<S<S<τ_0_0>>>>>>] => τ_0_0.[P:A].[P:A].[P:A].[P:A].[P:A] [subst↓]}}
-  // expected-error@-3 {{'A' is not a member type of type 'X'}}
-  // expected-error@-4 {{'A' is not a member type of type 'X'}}
     return S<X.A>()
   }
 }
diff --git a/validation-test/compiler_crashers_2_fixed/issue-54093.swift b/validation-test/compiler_crashers_2_fixed/issue-54093.swift
index c0d59f21127aa..55c766ead83b8 100644
--- a/validation-test/compiler_crashers_2_fixed/issue-54093.swift
+++ b/validation-test/compiler_crashers_2_fixed/issue-54093.swift
@@ -13,11 +13,12 @@ class Test1 {
 }
 
 @propertyWrapper 
-struct Wrapper2 { // expected-note {{property wrapper type 'Wrapper2' declared here}}
+struct Wrapper2 {
   var wrappedValue: Int??
 }
 
 class Test2 {
   @Wrapper2 var user: Int? 
-  // expected-error@-1 {{property type 'Int?' does not match that of the 'wrappedValue' property of its wrapper type 'Wrapper2'}}
+  // expected-error@-1 {{property type 'Int?' does not match 'wrappedValue' type 'Int??'}}
+  // expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Int' and 'Int?') are expected to be equal}}
 }
diff --git a/validation-test/compiler_crashers_2_fixed/issue-55443.swift b/validation-test/compiler_crashers_2_fixed/issue-55443.swift
index 928c1def248d1..0a25bcf9fe080 100644
--- a/validation-test/compiler_crashers_2_fixed/issue-55443.swift
+++ b/validation-test/compiler_crashers_2_fixed/issue-55443.swift
@@ -2,20 +2,20 @@
 
 // https://github.com/apple/swift/issues/55443
 
-enum FooString: String { // expected-error {{'FooString' declares raw type 'String', but does not conform to RawRepresentable and conformance could not be synthesized}} expected-note {{add stubs for conformance}}
-  case bar1 = #file // expected-error {{use of '#file' literal as raw value for enum case is not supported}}
-  case bar2 = #function // expected-error {{use of '#function' literal as raw value for enum case is not supported}}
-  case bar3 = #filePath // expected-error {{use of '#filePath' literal as raw value for enum case is not supported}}
-  case bar4 = #line // expected-error {{cannot convert value of type 'Int' to raw type 'String'}}
-  case bar5 = #column // expected-error {{cannot convert value of type 'Int' to raw type 'String'}}
-  case bar6 = #dsohandle // expected-error {{cannot convert value of type 'UnsafeRawPointer' to raw type 'String'}}
+enum FooString: String {
+  case bar1 = #file // expected-error {{raw value for enum case must be a literal}}
+  case bar2 = #function // expected-error {{raw value for enum case must be a literal}}
+  case bar3 = #filePath // expected-error {{raw value for enum case must be a literal}}
+  case bar4 = #line // expected-error {{raw value for enum case must be a literal}}
+  case bar5 = #column // expected-error {{raw value for enum case must be a literal}}
+  case bar6 = #dsohandle // expected-error {{raw value for enum case must be a literal}}
 }
 
-enum FooInt: Int { // expected-error {{'FooInt' declares raw type 'Int', but does not conform to RawRepresentable and conformance could not be synthesized}} expected-note {{add stubs for conformance}}
-  case bar1 = #file // expected-error {{cannot convert value of type 'String' to raw type 'Int'}}
-  case bar2 = #function // expected-error {{cannot convert value of type 'String' to raw type 'Int'}}
-  case bar3 = #filePath // expected-error {{cannot convert value of type 'String' to raw type 'Int'}}
-  case bar4 = #line // expected-error {{use of '#line' literal as raw value for enum case is not supported}}
-  case bar5 = #column // expected-error {{use of '#column' literal as raw value for enum case is not supported}}
-  case bar6 = #dsohandle // expected-error {{cannot convert value of type 'UnsafeRawPointer' to raw type 'Int'}}
+enum FooInt: Int {
+  case bar1 = #file // expected-error {{raw value for enum case must be a literal}}
+  case bar2 = #function // expected-error {{raw value for enum case must be a literal}}
+  case bar3 = #filePath // expected-error {{raw value for enum case must be a literal}}
+  case bar4 = #line // expected-error {{raw value for enum case must be a literal}}
+  case bar5 = #column // expected-error {{raw value for enum case must be a literal}}
+  case bar6 = #dsohandle // expected-error {{raw value for enum case must be a literal}}
 }
diff --git a/validation-test/compiler_crashers_2_fixed/issue-61031.swift b/validation-test/compiler_crashers_2_fixed/issue-61031.swift
index 177d6f04b287c..9ae81ffdebc8f 100644
--- a/validation-test/compiler_crashers_2_fixed/issue-61031.swift
+++ b/validation-test/compiler_crashers_2_fixed/issue-61031.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated
 
 public struct Wrapped<Values>: Sequence where Values: Sequence {
     public var values: Values
diff --git a/validation-test/compiler_crashers_2_fixed/issue-81712.swift b/validation-test/compiler_crashers_2_fixed/issue-81712.swift
new file mode 100644
index 0000000000000..d9e562bbca45b
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/issue-81712.swift
@@ -0,0 +1,20 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol Id {
+  associatedtype ID
+}
+
+protocol P<Id1> {
+  associatedtype Id1: Id
+  associatedtype Id2: Id where Id2.ID == Id1.ID
+
+  func foo(_: Id2.ID)
+}
+
+struct MyId: Id {
+  typealias ID = Int
+}
+
+func f(id: Int, cache: any P<MyId>) {
+  cache.foo(id)
+}
diff --git a/validation-test/compiler_crashers_2_fixed/rdar123543175.swift b/validation-test/compiler_crashers_2_fixed/rdar123543175.swift
index b808c30fd318a..1cb85c808cd4a 100644
--- a/validation-test/compiler_crashers_2_fixed/rdar123543175.swift
+++ b/validation-test/compiler_crashers_2_fixed/rdar123543175.swift
@@ -2,9 +2,8 @@
 
 public enum E : E.R {
 // expected-error@-1 {{'E' has a raw type that depends on itself}}
-// expected-note@-2 2{{through reference here}}
-// expected-note@-3 {{while resolving type 'E.R'}}
-// expected-error@-4 {{'R' is not a member type of enum 'rdar123543175.E'}}
-// expected-note@-5 {{'E' declared here}}
+// expected-note@-2 {{while resolving type 'E.R'}}
+// expected-error@-3 {{'R' is not a member type of enum 'rdar123543175.E'}}
+// expected-note@-4 {{'E' declared here}}
   case x
 }
diff --git a/validation-test/compiler_crashers_2_fixed/rdar146952007.swift b/validation-test/compiler_crashers_2_fixed/rdar146952007.swift
new file mode 100644
index 0000000000000..6362d4c725d1e
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/rdar146952007.swift
@@ -0,0 +1,45 @@
+// RUN: %target-swift-frontend -emit-sil %s
+
+// These cases are similar to https://github.com/swiftlang/swift/issues/80657,
+// but we can avoid hitting the same issue for non-enum members.
+
+struct S {
+  let y = 0
+  func foo(_ x: Int) {
+    let _ = { [self] in
+      switch x {
+      case y: break
+      default: break
+      }
+    }
+  }
+}
+
+class C {
+  let y = 0
+  func foo(_ x: Int) {
+    let _ = { [self] in
+      switch x {
+      case y: break
+      default: break
+      }
+    }
+  }
+}
+
+enum E {
+  case e
+
+  func bar() -> Int {0}
+
+  func foo() {
+    _ = { [self] in
+      switch 0 {
+      case bar():
+        break
+      default:
+        break
+      }
+    }
+  }
+}
diff --git a/validation-test/compiler_crashers_2_fixed/rdar151466803.swift b/validation-test/compiler_crashers_2_fixed/rdar151466803.swift
new file mode 100644
index 0000000000000..31b65a49a5a4a
--- /dev/null
+++ b/validation-test/compiler_crashers_2_fixed/rdar151466803.swift
@@ -0,0 +1,25 @@
+// RUN: not %target-swift-frontend -typecheck
+
+enum E: Error, Equatable {
+    case error1
+}
+
+public struct S {}
+
+public struct S2: AsyncSequence {
+    public typealias Element = S
+    public init() {}
+    public func makeAsyncIterator() -> AsyncIterator { return AsyncIterator() }
+    public struct AsyncIterator: AsyncIteratorProtocol {
+        public func next() async throws -> S? {
+            return nil
+        }
+    }
+}
+
+public struct S3: Sendable {
+    public func f() async throws -> AsyncSequence<S, E> {
+        return S2()
+    }
+}
+
diff --git a/validation-test/compiler_crashers_2_fixed/rdar87121502.swift b/validation-test/compiler_crashers_2_fixed/rdar87121502.swift
deleted file mode 100644
index 864080e26591d..0000000000000
--- a/validation-test/compiler_crashers_2_fixed/rdar87121502.swift
+++ /dev/null
@@ -1,16 +0,0 @@
-// RUN: %target-swift-frontend -emit-ir -target %target-cpu-apple-macosx10.15 %s
-// REQUIRES: OS=macosx
-
-protocol P {}
-
-func one() -> some P {
-    return two()
-}
-
-func two() -> some P {
-    return three()
-}
-
-func three() -> some P {
-    return one()
-}
diff --git a/validation-test/docs/userdoc_indices.test b/validation-test/docs/userdoc_indices.test
new file mode 100644
index 0000000000000..368c1e89848a8
--- /dev/null
+++ b/validation-test/docs/userdoc_indices.test
@@ -0,0 +1,15 @@
+# REQUIRES: swift_swift_parser
+# REQUIRES: target-same-as-host
+# REQUIRES: swift_feature_BareSlashRegexLiterals
+
+# RUN: %empty-directory(%t)
+
+# Check that the generated doc indices match those in the repo. Run
+# `./utils/generate-doc-index.swift <swift-source-directory>` to regenerate.
+
+# RUN: %host-build-swift -swift-version 5 -enable-upcoming-feature BareSlashRegexLiterals %swift_src_root/utils/generate-doc-index.swift -o %t/generate-doc-index
+# RUN: %t/generate-doc-index %swift_src_root %t
+
+# RUN: diff -u %swift_src_root/userdocs/diagnostics/diagnostic-descriptions.md %t/diagnostic-descriptions.md
+# RUN: diff -u %swift_src_root/userdocs/diagnostics/diagnostic-groups.md %t/diagnostic-groups.md
+# RUN: diff -u %swift_src_root/userdocs/diagnostics/upcoming-language-features.md %t/upcoming-language-features.md
diff --git a/validation-test/lit.site.cfg.in b/validation-test/lit.site.cfg.in
index 1b22413c47cb8..b3e779647178d 100644
--- a/validation-test/lit.site.cfg.in
+++ b/validation-test/lit.site.cfg.in
@@ -25,6 +25,7 @@ config.swift_src_root = "@SWIFT_SOURCE_DIR@"
 config.swift_obj_root = "@SWIFT_BINARY_DIR@"
 config.target_triple = "@LLVM_TARGET_TRIPLE@"
 config.variant_triple = "@VARIANT_TRIPLE@"
+config.variant_module_triple = "@VARIANT_MODULE_TRIPLE@"
 config.variant_suffix = "@VARIANT_SUFFIX@"
 config.variant_sdk = "@VARIANT_SDK@"
 config.swift_test_results_dir = \
@@ -137,6 +138,8 @@ config.swift_stdlib_enable_objc_interop = "@SWIFT_STDLIB_ENABLE_OBJC_INTEROP@" =
 # Configured in DarwinSDKs.cmake
 config.freestanding_sdk_name = "@SWIFT_SDK_FREESTANDING_LIB_SUBDIR@"
 
+config.swift_sdks = "@SWIFT_SDKS@".split(";")
+
 # Let the main config do the real work.
 config.test_exec_root = os.path.dirname(os.path.realpath(__file__))
 lit_config.load_config(config, os.path.join(config.test_exec_root, "lit.swift-features.cfg"))
diff --git a/validation-test/stdlib/Assert.swift b/validation-test/stdlib/Assert.swift
index 7df90cb4ba57b..acfadb0e6da7a 100644
--- a/validation-test/stdlib/Assert.swift
+++ b/validation-test/stdlib/Assert.swift
@@ -1,7 +1,10 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %s -Xfrontend -disable-access-control -o %t/Assert_Debug -Onone
-// RUN: %target-build-swift %s -Xfrontend -disable-access-control -o %t/Assert_Release -O
-// RUN: %target-build-swift %s -Xfrontend -disable-access-control -o %t/Assert_Unchecked -Ounchecked
+//
+// With -disable-access-control on, `_StringProcessing._internalInvariant` would shadow `Swift._internalInvariant`
+// RUN: %target-build-swift %s -Xfrontend -disable-access-control -Xfrontend -disable-implicit-string-processing-module-import -o %t/Assert_Debug -Onone
+// RUN: %target-build-swift %s -Xfrontend -disable-access-control -Xfrontend -disable-implicit-string-processing-module-import -o %t/Assert_Release -O
+// RUN: %target-build-swift %s -Xfrontend -disable-access-control -Xfrontend -disable-implicit-string-processing-module-import -o %t/Assert_Unchecked -Ounchecked
+//
 // RUN: %target-codesign %t/Assert_Debug
 // RUN: %target-codesign %t/Assert_Release
 // RUN: %target-codesign %t/Assert_Unchecked
diff --git a/validation-test/stdlib/CollectionDiagnostics.swift b/validation-test/stdlib/CollectionDiagnostics.swift
index 42e84834ca3de..583c2f3523caf 100644
--- a/validation-test/stdlib/CollectionDiagnostics.swift
+++ b/validation-test/stdlib/CollectionDiagnostics.swift
@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -verify-ignore-unknown
 
 import StdlibUnittest
 import StdlibCollectionUnittest
diff --git a/validation-test/stdlib/FixedPointDiagnostics.swift.gyb b/validation-test/stdlib/FixedPointDiagnostics.swift.gyb
index e091805af22b7..3f9c887c2ed00 100644
--- a/validation-test/stdlib/FixedPointDiagnostics.swift.gyb
+++ b/validation-test/stdlib/FixedPointDiagnostics.swift.gyb
@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %gyb %s -o %t/main.swift
-// RUN: %line-directive %t/main.swift -- %target-swift-frontend -typecheck -verify -swift-version 4.2 %t/main.swift
+// RUN: %line-directive %t/main.swift -- %target-swift-frontend -typecheck -verify -verify-ignore-unrelated -swift-version 4.2 %t/main.swift
 
 func testUnaryMinusInUnsigned() {
   var a: UInt8 = -(1) // expected-error {{no '-' candidates produce the expected contextual result type 'UInt8'}} expected-note * {{}} expected-warning * {{}}
@@ -53,8 +53,8 @@ func testMixedSignArithmetic() {
     Stride(1) - ${T}(0) // expected-error {{}} expected-note {{}}
 
     var y: Stride = 0
-    y += ${T}(1)        // expected-error {{cannot convert value of type '${T}' to expected argument type 'Int'}} {{10-10=Int(}}
-    y -= ${T}(1)        // expected-error {{cannot convert value of type '${T}' to expected argument type 'Int'}} {{10-10=Int(}}
+    y += ${T}(1)        // expected-error {{cannot convert value of type '${T}' to expected argument type 'Stride' (aka 'Int')}} {{10-10=Stride(}}
+    y -= ${T}(1)        // expected-error {{cannot convert value of type '${T}' to expected argument type 'Stride' (aka 'Int')}} {{10-10=Stride(}}
   }
 % end
 }
diff --git a/validation-test/stdlib/SIMDParameterPassing.swift.gyb b/validation-test/stdlib/SIMDParameterPassing.swift.gyb
index 41ed886313b9b..462870709e7fb 100644
--- a/validation-test/stdlib/SIMDParameterPassing.swift.gyb
+++ b/validation-test/stdlib/SIMDParameterPassing.swift.gyb
@@ -19,6 +19,7 @@
 // REQUIRES: executable_test
 // REQUIRES: long_test
 // XFAIL: OS=linux-gnu, OS=linux-android
+// UNSUPPORTED: OS=freebsd
 
 import StdlibUnittest
 import simd
diff --git a/validation-test/stdlib/StringWordBreaking.swift b/validation-test/stdlib/StringWordBreaking.swift
index 6597c38898763..d3a0ca0a4268a 100644
--- a/validation-test/stdlib/StringWordBreaking.swift
+++ b/validation-test/stdlib/StringWordBreaking.swift
@@ -2,35 +2,119 @@
 // RUN: %target-run-stdlib-swift %S/Inputs/
 
 // REQUIRES: executable_test
-// REQUIRES: objc_interop
 // REQUIRES: optimized_stdlib
+// REQUIRES: objc_interop
 
-@_spi(_Unicode)
-import Swift
+// FIXME: Text segmentation test cases are only available when we have Foundation
 
 import StdlibUnittest
 import StdlibUnicodeUnittest
 import Foundation
 
 let StringWordBreaking = TestSuite("StringWordBreaking")
+defer { runAllTests() }
 
-// FIXME: Reenable once we figure out what to do with WordView
-// @available(SwiftStdlib 5.7, *)
-// extension String._WordView {
-//   var backwardsCount: Int {
-//     var c = 0
-//     var index = endIndex
-//     while index != startIndex {
-//       c += 1
-//       formIndex(before: &index)
-//     }
-//     return c
-//   }
-// }
+extension String {
+  /// Returns all word boundaries within the string, using a single word
+  /// recognizer instance. This is the most efficient way to find word
+  /// boundaries, as it processes each scalar exactly once.
+  @available(StdlibDeploymentTarget 6.3, *)
+  func fastWordBreaks() -> [String.Index] {
+    var result: [String.Index] = []
+    var i = self.startIndex
+    var recognizer = Unicode._WordRecognizer()
+    var candidate = i
+    while i < self.endIndex {
+      let (setCandidate, breakAtCandidate, breakHere) =
+        recognizer.hasBreak(before: self.unicodeScalars[i])
+      if setCandidate {
+        candidate = i
+      }
+      if breakAtCandidate {
+        result.append(candidate)
+      }
+      if breakHere {
+        result.append(i)
+      }
+      self.unicodeScalars.formIndex(after: &i)
+    }
+    if recognizer.hasCandidateBreakAtEnd() {
+      result.append(candidate)
+    }
+    result.append(i)
+    return result
+  }
+
+  /// Return the word boundary position preceding a known boundary within this
+  /// string.
+  ///
+  /// This implements the word boundary specification of [Unicode Annex
+  /// #29](https://unicode.org/reports/tr29/#Default_Word_Boundaries). The
+  /// algorithm is not stable, and it allows implementers to tailor it to their
+  /// needs; accordingly, the result of this operation may vary between Unicode
+  /// implementations and system configurations, including versions of the Swift
+  /// Standard Library.
+  ///
+  /// - Note: If the input index is not on a word boundary, then it is first
+  /// rounded down to the nearest boundary before starting this operation.
+  ///
+  /// - Warning: Using this method to iterate over the word breaks in a string
+  ///    backward has worst-case complexity that is proportional to the _square_
+  ///    of the length of the string. It is usually a better idea to keep a
+  ///    cache of known word boundaries, calculated by iterating _forwards_ from
+  ///    the start index, or a position returned by
+  ///    `_wordIndex(somewhereAtOrBefore:)`.
+  ///
+  /// - Parameter i: A valid index addressing a word boundary within this
+  ///    string.
+  /// - Returns: The first word break strictly following `i` in the string.
+  @available(StdlibDeploymentTarget 6.3, *)
+  public func _wordIndex(before i: String.Index) -> String.Index {
+    let i = self.unicodeScalars._index(roundingDown: i)
+    var j = _wordIndex(somewhereAtOrBefore: unicodeScalars.index(before: i))
+
+    // We know there is a stable break at `j`, however, the backward search may
+    // have skipped over some conditional breaks that it could not fully
+    // evaluate. Find the closest actual break that precedes `i` by iterating
+    // forward until we reach or jump over it.
+    precondition(j < i)
+    var recognizer = Unicode._WordRecognizer()
+    var bestBreak = j
+    var candidate = j
+    while j < self.endIndex {
+      let r = recognizer.hasBreak(before: self.unicodeScalars[j])
+      if r.setCandidate { candidate = j }
+      if r.breakAtCandidate {
+        guard candidate < i else { break }
+        bestBreak = candidate
+      }
+      if r.breakHere {
+        guard j < i else { break }
+        bestBreak = j
+      }
+      self.unicodeScalars.formIndex(after: &j)
+    }
+    if j == self.endIndex, candidate < i, recognizer.hasCandidateBreakAtEnd() {
+      bestBreak = candidate
+    }
+    precondition(bestBreak < i)
+    return bestBreak
+  }
+}
 
 extension String {
+  @available(SwiftStdlib 6.3, *)
+  var statefulWords: [String] {
+    let breaks = fastWordBreaks()
+    var prev = breaks[0]
+    return breaks.dropFirst().map { next in
+      defer { prev = next }
+      return String(self[prev ..< next])
+    }
+  }
+
   @available(SwiftStdlib 5.9, *)
-  var _words: [String] {
+  var statelessWords: [String] {
     var result: [String] = []
 
     var i = startIndex
@@ -48,8 +132,8 @@ extension String {
     return result
   }
 
-  @available(SwiftStdlib 5.9, *)
-  var _wordsBackwards: [String] {
+  @available(SwiftStdlib 6.3, *)
+  var backwardWords: [String] {
     var result: [String] = []
 
     var i = endIndex
@@ -68,54 +152,22 @@ extension String {
   }
 }
 
-if #available(SwiftStdlib 6.1, *) {
-  StringWordBreaking.test("word breaking") {
-    for wordBreakTest in wordBreakTests {
-      expectEqual(
-        wordBreakTest.1,
-        wordBreakTest.0._words,
-        "string: \(String(reflecting: wordBreakTest.0))")
-      expectEqual(
-        wordBreakTest.1.reversed(),
-        wordBreakTest.0._wordsBackwards,
-        "string: \(String(reflecting: wordBreakTest.0))")
-    }
+extension Unicode.Scalar {
+  var unicodeNotation: String {
+      let v = String(self.value, radix: 16, uppercase: true)
+      return "U+\(String(repeating: "0", count: max(0, 4 - v.count)))\(v)"
   }
 }
 
-// rdar://116652595
-//
-// We were accidentally hanging when rounding word indices for some concoctions of
-// strings. In particular, where we had a pair of scalars create a constraint
-// for the preceding pair, but the preceding extend rules were not taking the
-// constraint into consideration.
-if #available(SwiftStdlib 5.10, *) {
-  StringWordBreaking.test("word breaking backward extend constraints") {
-    let strs = ["日\u{FE0F}:X ", "👨‍👨‍👧‍👦\u{FE0F}:X ", "⛔️:X ", "⛔️·X ", "⛔️：X "]
-    let strWords = [
-      ["日\u{FE0F}", ":", "X", " "],
-      ["👨‍👨‍👧‍👦\u{FE0F}", ":", "X", " "],
-      ["⛔️", ":", "X", " "],
-      ["⛔️", "·", "X", " "],
-      ["⛔️", "：", "X", " "]
-    ]
-
-    for (str, words) in zip(strs, strWords) {
-      expectEqual(
-        words,
-        str._words,
-        "string: \(String(reflecting: str))"
-      )
-
-      expectEqual(
-        words.reversed(),
-        str._wordsBackwards,
-        "string: \(String(reflecting: str))"
-      )
-    }
+extension String {
+  var scalarDescriptions: String {
+    return self.unicodeScalars
+      .lazy.map { $0.unicodeNotation }
+      .joined(separator: " ")
   }
 }
 
+#if _runtime(_ObjC)
 // The most simple subclass of NSString that CoreFoundation does not know
 // about.
 class NonContiguousNSString : NSString {
@@ -123,16 +175,17 @@ class NonContiguousNSString : NSString {
     fatalError("don't call this initializer")
   }
   required init(itemProviderData data: Data, typeIdentifier: String) throws {
-    fatalError("don't call this initializer")    
+    fatalError("don't call this initializer")
   }
 
-  override init() { 
+  override init() {
     _value = []
-    super.init() 
+    super.init()
   }
 
-  init(_ value: [UInt16]) {
-    _value = value
+  @inline(never)
+  init(_ value: some Sequence<UInt16>) {
+    _value = Array(value)
     super.init()
   }
 
@@ -157,36 +210,77 @@ extension _StringGuts {
   @_silgen_name("$ss11_StringGutsV9isForeignSbvg")
   func _isForeign() -> Bool
 }
-
-func getUTF16Array(from string: String) -> [UInt16] {
-  var result: [UInt16] = []
-
-  for cp in string.utf16 {
-    result.append(cp)
+#endif
+
+func testCases() -> [(String, [String])] {
+  var tests = StdlibUnicodeUnittest.wordBreakTests
+  if #available(SwiftStdlib 5.10, *) {
+    // rdar://116652595
+    //
+    // We were accidentally hanging when rounding word indices for some
+    // concoctions of strings. In particular, where we had a pair of scalars
+    // create a constraint for the preceding pair, but the preceding extend
+    // rules were not taking the constraint into consideration.
+    tests += [
+      ("日\u{FE0F}:X ", ["日\u{FE0F}", ":", "X", " "]),
+      ("👨‍👨‍👧‍👦\u{FE0F}:X ", ["👨‍👨‍👧‍👦\u{FE0F}", ":", "X", " "]),
+      ("⛔️:X ", ["⛔️", ":", "X", " "]),
+      ("⛔️·X ", ["⛔️", "·", "X", " "]),
+      ("⛔️：X ", ["⛔️", "：", "X", " "]),
+    ]
   }
+  if #available(SwiftStdlib 6.3, *) {
+    tests += [
+      // https://github.com/swiftlang/swift-experimental-string-processing/issues/818
+      // rdar://154902007
+      ("\u{2060}\u{2018}\u{2060}\u{2060}example.com\u{2060}\u{2060}\u{2019}",
+       ["\u{2060}", "\u{2018}\u{2060}\u{2060}", "example.com\u{2060}\u{2060}", "\u{2019}"]),
+    ]
+  }
+  return tests
+}
 
-  return result
+if #available(SwiftStdlib 6.1, *) {
+  StringWordBreaking.test("word breaking") {
+    for (input, expectedWords) in testCases() {
+      expectEqual(
+        input.statelessWords,
+        expectedWords,
+        "input: \(input.debugDescription) \(input.scalarDescriptions)")
+      if #available(SwiftStdlib 6.3, *) {
+        expectEqual(
+          input.statefulWords,
+          expectedWords,
+          "input: \(input.debugDescription) \(input.scalarDescriptions)")
+        expectEqual(
+          input.backwardWords,
+          expectedWords.reversed(),
+          "input: \(input.debugDescription) \(input.scalarDescriptions)")
+      }
+    }
+  }
 }
 
 if #available(SwiftStdlib 6.1, *) {
   StringWordBreaking.test("word breaking foreign") {
-    for wordBreakTest in wordBreakTests {
-      let foreignTest = NonContiguousNSString(
-        getUTF16Array(from: wordBreakTest.0)
-      )
-      let test = foreignTest as String
+    for (nativeString, expectedWords) in testCases() {
+      let input = NonContiguousNSString(nativeString.utf16) as String
 
-      expectTrue(test._guts._isForeign())
+      expectTrue(input._guts._isForeign())
       expectEqual(
-        wordBreakTest.1,
-        test._words,
-        "string: \(String(reflecting: wordBreakTest.0))")
-      expectEqual(
-        wordBreakTest.1.reversed(),
-        test._wordsBackwards,
-        "string: \(String(reflecting: wordBreakTest.0))")
+        input.statelessWords,
+        expectedWords,
+        "input: \(nativeString.debugDescription) \(nativeString.scalarDescriptions)")
+      if #available(SwiftStdlib 6.3, *) {
+        expectEqual(
+          input.statefulWords,
+          expectedWords,
+          "input: \(nativeString.debugDescription) \(nativeString.scalarDescriptions)")
+        expectEqual(
+          input.backwardWords,
+          expectedWords.reversed(),
+          "input: \(nativeString.debugDescription) \(nativeString.scalarDescriptions)")
+      }
     }
   }
 }
-
-runAllTests()
diff --git a/validation-test/stdlib/UnicodeWordRecognizer.swift b/validation-test/stdlib/UnicodeWordRecognizer.swift
new file mode 100644
index 0000000000000..352199139786e
--- /dev/null
+++ b/validation-test/stdlib/UnicodeWordRecognizer.swift
@@ -0,0 +1,311 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-run-stdlib-swift
+
+// REQUIRES: executable_test
+// REQUIRES: objc_interop
+// REQUIRES: optimized_stdlib
+
+// Validate that the various forms of word breaking all lead to consistent
+// results by exhaustively enumerating all possible state machine inputs up to
+// an adequately high length.
+//
+// The word breaking algorithm only cares about word break properties, not
+// specific scalar values. This lets us only use a single representative sample
+// in each class, drastically cutting down the input space to iterate through.
+// This makes it practical to do this up to limits that give us practically
+// useful results.
+
+import StdlibUnittest
+
+let suite = TestSuite("UnicodeWordRecognizer")
+defer { runAllTests() }
+
+// One representative sample from each character class that's relevant to word breaking
+let samples: [Unicode.Scalar] = [
+  "\u{000D}", // CR
+  "\u{000A}", // LF
+  "\u{2028}", // Newline (LINE SEPARATOR)
+  "\u{0041}", // ALetter (LATIN CAPITAL LETTER A)
+  "\u{0022}", // Double_Quote (QUOTATION MARK)
+  "\u{0027}", // Single_Quote (APOSTROPHE)
+  "\u{200D}", // ZWJ (ZERO WIDTH JOINER)
+  "\u{1F1E6}", // RI (REGIONAL INDICATOR SYMBOL LETTER A)
+  "\u{05D0}", // Hebrew_Letter (HEBREW LETTER ALEF)
+  "\u{0300}", // Extend (COMBINING GRAVE ACCENT)
+  "\u{00AD}", // Format (SOFT HYPHEN)
+  "\u{3031}", // Katakana (VERTICAL KANA REPEAT MARK)
+  "\u{003A}", // MidLetter (COLON)
+  "\u{002C}", // MidNum (COMMA)
+  "\u{002E}", // MidNumLet (FULL STOP)
+  "\u{0030}", // Numeric (DIGIT ZERO)
+  "\u{005F}", // ExtendNumLet (LOW LINE)
+  "\u{0020}", // WSegSpace (SPACE)
+  "\u{00A9}", // \p{Extended_Pictographic} (COPYRIGHT)
+  "\u{0021}", // Any (EXCLAMATION MARK)
+]
+
+/// Call `body` with every array of the specified count consisting of
+/// integer elements in the given range. This is calculating the
+/// Cartesian `n`-ary power of the `range` argument.
+///
+///     withEveryArray(of: 1 ..< 3, count: 3) { print($0) }
+///     // [1, 1, 1]
+///     // [2, 1, 1]
+///     // [1, 2, 1]
+///     // [2, 2, 1]
+///     // [1, 1, 2]
+///     // [2, 1, 2]
+///     // [1, 2, 2]
+///     // [2, 2, 2]
+func withEveryArray<E: Error>(
+  of range: Range<Int>,
+  count n: Int,
+  _ body: ([Int]) throws(E) -> Void
+) throws(E) {
+  var vector: [Int] = .init(repeating: range.lowerBound, count: n)
+  guard n > 0 else {
+    try body(vector)
+    return
+  }
+  while true {
+    try body(vector)
+    var i = 0
+    while true {
+      vector[i] += 1
+      if vector[i] < range.upperBound {
+        break
+      }
+      vector[i] = range.lowerBound
+      i += 1
+      if i == n {
+        return // done
+      }
+    }
+  }
+}
+
+func string(for vector: [Int]) -> String {
+  var s = ""
+  for digit in vector {
+    s.unicodeScalars.append(samples[digit])
+  }
+  return s
+}
+
+extension Unicode.Scalar {
+  var unicodeNotation: String {
+      let v = String(self.value, radix: 16, uppercase: true)
+      return "U+\(String(repeating: "0", count: max(0, 4 - v.count)))\(v)"
+  }
+}
+
+extension String {
+  var scalarDescriptions: String {
+    return self.unicodeScalars
+      .lazy.map { $0.unicodeNotation }
+      .joined(separator: " ")
+  }
+}
+
+extension Collection {
+  /// Return a sorted array of all valid indices in the collection, including
+  /// the end index.
+  func allIndices() -> [Index] {
+    var result: [Index] = []
+    result.reserveCapacity(count + 1)
+    result.append(contentsOf: indices)
+    result.append(endIndex)
+    return result
+  }
+}
+
+extension Sequence where Element: Equatable {
+  /// Returns true if the elements of `self` form a sub-sequence of `other`,
+  /// where both inputs are monotonic. `self` is not allowed to contain
+  /// more than a single copy of any item in `other`.
+  func isMonotonicSubsequence(of other: some Sequence<Element>) -> Bool {
+    var i = makeIterator()
+    var j = other.makeIterator()
+    var b = j.next()
+    while let a = i.next() {
+      while true {
+        if b == nil { return false }
+        if a == b {
+          b = j.next()
+          break
+        }
+        b = j.next()
+      }
+    }
+    return true
+  }
+
+  /// Returns true if the elements of `self` form a sub-sequence of `other`,
+  /// where both inputs are monotonic. `self` is allowed to contain duplicate
+  /// elements.
+  func isMonotonicRepeatingSubsequence(of other: some Sequence<Element>) -> Bool {
+    var i = makeIterator()
+    var j = other.makeIterator()
+    var b = j.next()
+    while let a = i.next() {
+      while true {
+        if b == nil { return false }
+        if a == b { break }
+        b = j.next()
+      }
+    }
+    return true
+  }
+
+}
+
+extension String {
+  /// Returns all word boundaries within the string, using a single word
+  /// recognizer instance. This is the most efficient way to find word
+  /// boundaries, as it processes each scalar exactly once.
+  @available(StdlibDeploymentTarget 6.3, *)
+  func fastWordBreaks() -> [String.Index] {
+    var result: [String.Index] = []
+    var i = self.startIndex
+    var recognizer = Unicode._WordRecognizer()
+    var candidate = i
+    while i < self.endIndex {
+      let (setCandidate, breakAtCandidate, breakHere) =
+        recognizer.hasBreak(before: self.unicodeScalars[i])
+      if setCandidate {
+        candidate = i
+      }
+      if breakAtCandidate {
+        result.append(candidate)
+      }
+      if breakHere {
+        result.append(i)
+      }
+      self.unicodeScalars.formIndex(after: &i)
+    }
+    if recognizer.hasCandidateBreakAtEnd() {
+      result.append(candidate)
+    }
+    result.append(i)
+    return result
+  }
+
+  /// Returns all word breaks without keeping persistent state, using
+  /// `_wordIndex(after:)`. This forgets lookahead information after each word
+  /// boundary, so it needs to process some scalars twice, resulting in a
+  /// performance regression vs `fastWordBreaks()`. However, both variants are
+  /// supposed to have the same results.
+  @available(StdlibDeploymentTarget 5.7, *)
+  func slowWordBreaks() -> [String.Index] {
+    var result: [String.Index] = []
+    var i = self.startIndex
+    while i < self.endIndex {
+      result.append(i)
+      i = self._wordIndex(after: i)
+    }
+    result.append(i)
+    return result
+  }
+
+  /// Return all "safe" word breaks in this string by using the backwards word
+  /// recognizer state machine, starting from the end, feeding it every Unicode
+  /// scalar in the string, and collecting all word boundaries detected.
+  ///
+  /// This is expected to sometimes skip over word boundaries that are detected
+  /// when going forward. However, it must never report a word boundary at a
+  /// position that isn't also detected by the forward recognizer.
+  @available(StdlibDeploymentTarget 6.3, *)
+  func safeWordBreaks() -> [String.Index] {
+    var result: [String.Index] = []
+    guard !self.isEmpty else { return result }
+    result.append(self.endIndex) // There is always an implicit wordbreak at the end.
+    var i = self.unicodeScalars.index(before: self.endIndex)
+    var recognizer = Unicode._RandomAccessWordRecognizer(before: self.unicodeScalars[i])
+    var candidate = i
+    while i > self.startIndex {
+      let j = self.unicodeScalars.index(before: i)
+      let r = recognizer.hasGuaranteedBreak(after: self.unicodeScalars[j])
+      if r.setCandidate {
+        candidate = i
+      }
+      if r.breakAtCandidate {
+        result.append(candidate)
+      }
+      if r.breakHere {
+        result.append(i)
+      }
+      i = j
+    }
+    result.reverse()
+    return result
+  }
+
+  /// Return an array of "safe" word boundaries detected by the backwards word
+  /// recognizer state machine, invoked through
+  /// `_wordIndex(somewhereAtOrBefore:)`, one result per each scalar position in
+  /// the string (including its end index).
+  ///
+  /// This is expected to be some monotonically increasing subsequence of word
+  /// boundaries detected in the forward direction, allowing some repeated
+  /// items.
+  @available(StdlibDeploymentTarget 6.3, *)
+  func randomAccessWordBreaks() -> [String.Index] {
+    unicodeScalars.allIndices().map { self._wordIndex(somewhereAtOrBefore: $0) }
+  }
+}
+
+@available(StdlibDeploymentTarget 6.3, *)
+func check(length: Int) {
+  withEveryArray(of: 0 ..< samples.count, count: length) { vector in
+    let str = string(for: vector)
+
+    let fastBreaks = str.fastWordBreaks()
+    let slowBreaks = str.slowWordBreaks()
+    expectEqual(
+      fastBreaks, slowBreaks,
+      """
+      Inconsistent word boundaries in stateful vs stateless iteration:
+        input: \(str.debugDescription) (\(str.scalarDescriptions))
+      """)
+
+    let safeBreaks = str.safeWordBreaks()
+    expectTrue(
+      safeBreaks.isMonotonicSubsequence(of: fastBreaks),
+      """
+      Inconsistent safe word boundaries:
+        input: \(str.debugDescription) (\(str.scalarDescriptions))")
+      """)
+
+    let randomAccessBreaks = str.randomAccessWordBreaks()
+    expectTrue(
+      randomAccessBreaks.isMonotonicRepeatingSubsequence(of: fastBreaks),
+      """
+      Inconsistent random-access word boundaries:
+        input: \(str.debugDescription) (\(str.scalarDescriptions))
+        breaks:               \(fastBreaks)
+        random-access breaks: \(randomAccessBreaks)
+      """)
+  }
+}
+
+if #available(StdlibDeploymentTarget 6.3, *) {
+  suite.test("Exhaustive consistency checks, length 1") {
+    check(length: 1)
+  }
+
+  suite.test("Exhaustive consistency checks, length 2") {
+    check(length: 2)
+  }
+
+  suite.test("Exhaustive consistency checks, length 3") {
+    check(length: 3)
+  }
+
+  suite.test("Exhaustive consistency checks, length 4") {
+    check(length: 4)
+  }
+
+  suite.test("Exhaustive consistency checks, length 5") {
+    check(length: 5)
+  }
+}
diff --git a/validation-test/stdlib/UnsafeBufferPointer.swift.gyb b/validation-test/stdlib/UnsafeBufferPointer.swift.gyb
index ada9a8f6277d2..a5566bccb2559 100644
--- a/validation-test/stdlib/UnsafeBufferPointer.swift.gyb
+++ b/validation-test/stdlib/UnsafeBufferPointer.swift.gyb
@@ -287,8 +287,11 @@ ${SelfName}TestSuite.test("badCount")
 
   let emptyAllocated = UnsafeMutablePointer<Float>.allocate(capacity: 0)
   defer { emptyAllocated.deallocate() }
+  
+  // Make sure we can't emit the error at compile time
+  @inline(never) var badCount: Int { -1 }
 
-  let buffer = ${SelfType}(start: ${PointerType}(emptyAllocated), count: -1)
+  let buffer = ${SelfType}(start: ${PointerType}(emptyAllocated), count: badCount)
   _ = buffer
 }